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  • Inorganic Chemistry  (809)
  • Cell & Developmental Biology  (413)
  • 1990-1994
  • 1970-1974  (1,222)
  • 1955-1959
  • 1930-1934
  • 1970  (1,222)
Collection
Publisher
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  • 1990-1994
  • 1970-1974  (1,222)
  • 1955-1959
  • 1930-1934
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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 130 (1970), S. 1-1 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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  • 2
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Electron microscope studies on Tylocephalum metacestodes embedded in the tissues of the oyster, Crassostrea virginica, have revealed that the tegument of the larval tapeworm is comprised of an external and an internal level which are partially separated by a basal lamina and two layers of muscles. The outer tegumentary level is comprised of an anucleate, cytoplasmic syncytium in which are embedded large and small vesicles and mitochondria. Surfacial hooks are also embedded therein. The internal level is comprised of relatively large discrete cells including mitochondria, rough endoplasmic reticulum, and large and small vesicles. These cells are intermittently connected with the external level by cytoplasmic bridges.Arising from the external level are unusual microvilli each of which terminates as a spherical vesicle. The stem of each microvillus is covered by a unit membrane which is continuous with that overlaying the body surface. In addition, each microvillus includes an external layer of medium electron density, a medial layer of intense electron density, and a core of heterogenous, medium electron density. These structures may be intertwined and bundles can be observed at the light microscope level as fibril-like projections from the parasite's body surface. One of their possible functions may be to prevent intimate contact between the encapsulating fibers of host origin and the parasite's body surface. In addition, the contraction and distention of the circular muscles result in microvillar movement which may keep the surrounding host fluids, including those of nutritional importance to the parasite, in a state of flux thus hypothetically permitting more uniform uptake.The abundance of vesicles in the syncytial external level of the tegument appears to be characteristic of the more primitive marine cestodes belonging to the orders Trypanorhyncha and Lecanicephala.
    Additional Material: 11 Ill.
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  • 3
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The structural changes of mitochondria that occur during oogenesis and early embryogenesis in the rabbit have been examined with the electron microscope. Mitochondria of oogonia are both elongate and oval and contain a variable number of cristae which may or may not traverse the longitudinal axis of the organelle. When oogonia differentiate into oocytes, mitochondria become spheroidal and their cristae are sparse when compared with those found in the ellipsoidal organelles of concomitantly maturing follicle cells. As differentiation proceeds, the cristae of the mitochondria display varied configurations. For example, many display an arch-like arrangement in several regions of the organelle whereas others contain a pair of concentric membranes closely associated with limiting membrane of the mitochondrion.Mitochondria of stages from the fertilized egg to the morula possess the same internal structure as those of young oocytes. As the morula differentiates into a blastocyst there is a gradual increase in the size of the mitochondria and an increase in the number of cristae. We believe that the number and modifications of cristae indicate stages of mitochondriogenesis and the level of enzymatic activity in which this organelle is engaged during oogenesis and early embryogenesis.
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 130 (1970), S. 129-135 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The reproductive tracts of several species of lizards were examined to understand the events assoclated with the transport of discharged oocytes following ovulation. At the onset of the reproductive cycle the regressed ovaries and oviducts appear as inconspicuous structures pressed against the dorsal body wall. As the reproductive cycle progresses, they undergo marked changes in position and size. The oviducts migrate ventrally and surround the growing ovarian oocytes, which move anteriorly where coelomic space is more abundant and eventually press intimately against the infundibulum. When ovulation occurs the ostium is in a remarkably strategic location for directly receiving the ovulated oocytes. The virtual isolation of the ovaries from the general coelom by the encapsulating oviducts, and the intimate association of the pre-ovulatory oocytes with the infundibular ostium do not support the current concept advocating the migration of loose ova following ovulation. An alternative explanation for the “trans-coelomic migratiion of ova” is proposed.
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  • 5
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The black carpet beetle, Attagenus megatoma (Fab.), has been reported to exhibit negative phototaxis immediately after emergence. In later adult life, after the period during which most oviposition has occurred, the beetles are found to be photopositive. The compound eyes of one-day-old (Post-emergence) and nine-day-old (Post-ovipositional) female beetles were studied by electron microscopy and a number of strong differences were found between eyes at the two ages. The corneal facets of one-day eyes had the form of convex-concave lenses, while those of nine-day beetles were double-convex lenses. The primary and secondary pigment cells of young eyes were large and contained much endoplasmic reticulum and little accessory pigment. In the older eyes the pigment cells were reduced and contained much pigment, the proportion of endoplasmic reticulum being greatly reduced by comparison with the one-day eye. The cross-sectional area of the rhabdom was greater in the older eye.The possible relationships between age-related changes in eye morphology and behavioral changes during the same period are discussed.
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  • 6
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Somites, along with adjacent neural tube and overlying ectoderm, were extirpated unilaterally from embryos of Chelydra serpentina. Mesoderm of three somites was removed from various levels. The operations included the last formed somite and were done on embryos with 12 to 22 pairs of somites. In practice it was found that ventromedial portions of the somites were not included in the extirpation. The animals were preserved before pigmentation became heavy. The cartilaginous skeleton was stained selectively.The extirpations resulted in depletions of ribs consonant with relating the second rib to the fourteenth somite. The somites behaved as mosaics; they did not reconstitute each other nor did they regenerate after partial extirpation. The rudiments for the ribs were separable from the rudiments of the vertebrae, the sclerotomes, and were found to arise from a more lateral portion of the somite.The scutes are ectodermal derivatives, which are held to be dependent upon underlying somitic mesoderm for their differentiation. The extirpations resulted in abnormalities and depletions of scutes.
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 132 (1970) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 132 (1970), S. 245-263 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The aggregation in vitro of embryonic neural retina cells was studied by electron microscopy with special emphasis on the reformation of intercellular junctions. The results show that (1) embryonic neural retina cells dissociated with trypsin retain morphological characteristics and polarity after dispersion into a suspension; (2) initial adhesions between the aggregating cells are nonspecific with respect to cell type and to the site of cell surface involved; (3) histogenetic associations in clusters of reaggregated cells appear within two hours after the start of aggregation. A hypothesis is presented that coated vesicles play a role in the formation of intercellular junctions.
    Additional Material: 11 Ill.
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  • 9
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Histological analyses of monthly collections of Sceloporus jarrovi ovaries are presented. The ovaries undergo a cycle in which yolk deposition occurs in September-October and is followed by ovulation in late November. One corpus luteum forms from each ruptured follicle and undergoes progressive cytoplasmic depletion until mid-June parturition, after which time rapid degeneration commences. Follicular atresia is common during the spring and absent during the summer and early fall. Granulosa cells play an active role in follicular atresia luteal cell formation, and may also be involved in yolk deposition.
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  • 10
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Observations on inner ear structure were made in five species of Scincidae, together with measurements of auditory sensitivity in terms of cochlear potentials. The basilar membrane and auditory papilla show a characteristic form, with considerable uniformity in dimensions except for a moderate expansion in the dorsal region and a more prominent one at the ventral end.A characteristic feature is the presence of a tectorial membrane that covers a large part of the surface of the medial limbus, but never leaves this surface and thus fails to make any contact with the auditory papilla. Hair-cell stimulation is achieved entirely through operation of the inertia principle (or equivalent principles) by means of a chain of sallets extending along most of the cochlea but giving way in the region of the ventral expansion to a single large body, the culmen papillae.The sensitivity varies in the five skinks studied from better than average to some-what below average in comparison with other lizard species. Thus an inertial (or inertia-like) system of hair-cell stimulation compares favorably with the tectorial membrane (restraint) system exhibited in the ears of most other lizards and all the higher animals.
    Additional Material: 14 Ill.
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  • 11
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Virgin mosquitoes were studied with the electron microscope. Spermathecal duct walls contain cuticle, epithelium, and a richly innervated spiral muscle; myocytes are linked by desmosome-like attachment plaques to the underlying epithelium. Periductal cells along upper portions of the ducts have a large secretory droplet within a highly irregular extracellular lacuna and are attached to a long secretory ductule through which finely granular material is delivered to the duct lumen and this enters the spermathecae. Basal gland cells of spermathecae have short ductules containing secretion in virgins. Secretory material in spermathecae of virgins does not form a complete internal membrane.
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  • 12
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 132 (1970), S. 313-333 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Spiders possess curved, blunt-tipped hairs on all legs and palps, which differ in many details from the straight, sharp-pointed, tactile hairs: (1) the blunt tip is open to the outside, which can be demonstrated by high resolution microscopy and by the penetration of dyes; (2) the hair shaft has a double lumen which consists of a circular (tube) and a crescent shaped lumen; (3) this hair is innervated by two to three bipolar neurons whose dendrites enter the small tube, where they arborize into 16-20 branches. Multiple innervation and an open tip give strong evidence for a chemoreceptive function. Concluding from their position and distribution on the distal leg parts, a contact chemoreception is tentatively proposed. This interpretation is supported by the close structural analogy to the known contact chemoreceptors in insects. Observation of behavior indicates the importance of a contact chemoreceptor on spider legs. Other possible chemoreceptors in spiders which have been described previously by other authors are discussed.
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  • 13
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Two types of coelomocytes, the mucocyte and the phagocyte, occur in Enchytraeus fragmentosus. Other free cells observed within the coelomic cavity include chloragogen cells, peritoneal cells and some anucleate granular cells. Three forms of mucocytes occur and are believed to represent developmental stages. The first stage is one in which the mucous droplets are forming in the Golgi region. The second stage is a mature form, and the third stage is one in which the mucous droplets are being released. The phagocytes generally are quite large, and inclusions vary from recognizable portions of chloragogen cells to extremely small, electron-dense cytosomes. The origin of the coelomocytes could not be determined. Probable functions of coelomocytes are discussed.
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  • 14
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 132 (1970) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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  • 15
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In a study of survival of embryonic grafts in turtles, Chelydra was used as host and Chrysemys and Amyda as donors. Somites and overlying ectoderm with or without adjacent neural tube were transplanted. The operations were unilateral and orthotopic. The involved the anterior portion of the carapace. In other experiments, bilateral neural crest and dorsal neural tube were transplanted orthotopically.In experiments with Chrysemys as donor, pigment cells formed conspicuous red areas ventrally when neural crest was included in the graft. This pigment faded gradually but persisted for three or four years.When somites and adjacent ectoderm of Chrysemys carapace were transplanted, the graft area was lightly pigmented at hatching. This pigmentation increased subsequently. The Chrysemys grafts were either accepted or partially rejected. In cases of apparent complete acceptance, the graft region took on characteristics of the host.When Amyda served as donor of carapace rudiments, the graft area retained characteristics of the donor. At hatching, dark spots on a yellow background were present and scutes were absent. A few months after hatching, the graft area became necrotic. Subsequently, scutes with host characteristics or skin covered the graft area.
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  • 16
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Large number of annuli in Hirudinea are not true segments, and in the absence of spacious bodycavity and septa in adult no decision was taken regarding limit of a somite, until Gratiolet 1862 recognised a segment by colour marking, repetition of nephridial openings, and especially by the presence of segmental receptors, distinguishing first annulus of a segment. Whitman 1884 gave precision to these determinations and analyzed morphology of leeches to logical completeness. He recognised that though Hirudinaria and Hirudo have 102 body annuli and posterior sucker, true segments are only 26 plus 7.Castle ('00) and Moore ('00) proposed a new scheme of segmentation, with segmental receptor bearing annulus, as central annulus of a complete somite, with nerve ganglion, like that of other annelids, in center of a segment. They orientated everything roundabout the ganglion without noticing distorted fate of organ system.In this paper both the views are compared. Morphological and embryological studies reveal that the annulus bearing the segmental receptors in uniformly first annulus of all segments, including incomplete segments at the two extremities, with nerve ganglion in first annulus of the segment.Clitellum occupies three natural segments, IX, X, XI; crop caeca, nephridia, testis sacs, haemocoelomic channels and “rhomboidal figures” formed by ventrolaterals, all make a complete unit, well integrated in such segment. Conclusive evidence comes from the presence of septa at the level of each nerve ganglion in embryos of Hirudinaria. These observations corroborate Gratiolet and Whitman's view.
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  • 17
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 132 (1970), S. 377-387 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Tooth development in Latimeria was studied with the use of light microscopy, polarized light microscopy and microradiography.Teeth develop from cells derived directly from the basal layer of the oral epithelium in areas where teeth have been shed or are being resorbed. The teeth are composed of true enamel, orthodentine and pulp tissues. Attachment is accom-plished by bony attachment ankylosing the teeth to the basal bone of dental plates. The histologic picture of Latimeria teeth resembles more closely the teeth of tetrapods than those of most bony fish.
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  • 18
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 132 (1970), S. 389-395 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Changing spermatozoan associations were observed in the epididymides of several mammals. These associations ranged from closely interwoven cylindrical bodies, found in the proximal part of the epididymis, to disorganized masses of spermatozoa, found in the distal part of the duct. It is suggested that changes in the cohesive properties of epididymal spermatozoa resulted in the formation and fragmentation of cylindrical bodies. These bodies, differeing in pattern and complexity according to the species, were found in all investigated mammals, including man. Cohesiveness appeared first in the upper part of the epididymidis, where it was confined to the spermatozoan tails. In general, there was a diminution of cohesive forces as the spermatozoa passed down the epididymal duct; consequently, the cylindrical bodies turned into disorganized masses of spermatozoa. There are indications that changes in the cohesive properties of spermatozoa may represent one aspect of spermatozoan maturation.
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  • 19
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The penis is basically a double-walled oval cone. The weak type penis (only 2 species) has a weak tongue, lacks a bridge, and is elongate. The strong type (all others) has a bridge, a strong tongue, thicker walls, and is short. An accessory gland and a common vas deferens always open into the inner cup lumen (= ejaculatory duct). The massive tongue muscles may open the penal orifice. A pair of penal retractor muscles originate on the body wall. Penal protrusion and perhaps partial extrusion of stalk substance is by hemolymph pressure. The penis is completely homologous to the ovipositor. The genital discs are cuticular cups containing glandular tissue and are retractible by muscles originating on the body wall. The minute, rod-like, immobile sperm are mixed with seminal fluid and stalk material secreted by seminal vesicle cells. This mixture is carried via the vase deferentia by peristalsis to the penis. Semen and stalk substance (protein) are somehow separated in the ejaculatory duct into separate pools, with stalk substance nearest the penal orifice. Upon penal protrusion, a bit of stalk material is extruded and fastened to the ground, and upon raising of the mite's body the stalk is “drawn out.” Finally, the ball of semen, adhering to the stalk tip, is pulled through the penal orifice.
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  • 20
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 132 (1970), S. 397-423 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Sperm from the male spermatophore in the red spotted newt are held indefinitely in convoluted, tubular outpocketings of the female cloaca called, collectively, a spermatheca. Each outpocketing, or tubule, when studied in thin section with the electron microscope showed a wall consisting of two components, a continuous inner or lining layer of epithelial cells and an outer covering layer of myoepithelial cells.The myoepithelial layer is penetrated by occasional openings or intercellular spaces through which the epithelial cells make contact with a basal lamina that bounds the tubule. The myoepithelial cells resemble smooth muscle cells displaying filaments (mean diameter = 75 Å ± 1 S.E.) that are probably constituted of actin, dense bodies and prominent caveolae. They are sparsely supplied with mitochondria, ribosomes, Golgi complexes and, sometimes, particles of glycogen. Typically the epithelial cells contain secretion granules, numerous mitochondria and ribosomes. They contain some fibers similar to those of the myoepithelial cells but with mean diameters that are significantly larger (90 Å ± 2 S.E.). Occasional profiles of Golgi complexes are evident and glycogen particles are abundant throughout the cytosomes of spermathecal tubules from adult animals bearing sperm. Secretory granules and glycogen are extremely rare or lacking in the spermathecae of efts that have not attained sexual maturity and in animals with ablated or involuted ovaries. In such animals large electron-lucid vesicles appear at or near luminal borders. Glycogen is absent and secretory granules show signs of dissolution in the spermathecal cells of gravid females induced to ovulate by the injection of chorionic gonadotropin. It is indicated that the epithelial cells provide nourishment for the sperm while they are retained within the spermathecal tubules, that the discharge of sperm from the spermatheca is facilitated by the contraction of the myoepithelial cells and that gonadal hormones act in the regulation of spermathecal function.
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  • 21
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The mitotic and labelling incidence of intestine, liver, spleen and pancreas cells of Triturus cristatus carnifex adults kept at 15°C, 20°C, 25°C and 30°C were examined. Intestine mitotic and labelling incidences were highest at 25°C and lowest at 30°C. There was no significant difference between 15°C and 20°C. No such relationship could be shown for liver, spleen or pancreas, which had very much lower mitotic and labelling incidences. In culture, intestine mitotic and labelling incidences fell significantly within the first four hours, and maintained these low levels for the next five days. In contrast, liver mitotic and labelling incidences rose for 9-11 days, and then began to fall, while pancreas mitotic and labelling incidences reached peak values at day 5, and were kept in good condition for up to 14 days.
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  • 22
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A fine structural analysis of the ovotestis in Aplysia was undertaken in order to analyze the site of action of the bag cell hormone. Five stages of oocyte development are described. Of particular interest is the fact that the yolk seems to be synthesized primarily by the granular endoplasmic reticulum. In addition, small muscle cells whose long, thin processes surround the follicle of the ovotestis have been pointed out. This paper suggests that bag cell extract has a direct action on these small muscle cells causing them to contract and thus expel oocytes from the ovotestis. The evidence for this suggestion is that (1) these muscle cells are the most obvious effector cells in the ovotestis, (2) there are no signs of neural innervation of these muscles, (3) the time course for the liberation of the oocytes is so short that any other method of oocyte release is unlikely, (4) there is no cytologic evidence for any other expulsion process except muscular contraction, and (5) the ripe oocytes are attached to other cells of the wall of the ovotestis only by very small, simple junctions, thus making them the most likely cells to be expelled by muscular contraction.
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  • 23
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The renal corpuscle of the opisthonephric kidney of the Great Lakes lamprey, Petromyzon marinus L., is described. In the larvae (ammocoetes) several renal corpuscles, each consisting of lobed glomeruli and Bowman's capsules, are placed behind one another and there is a progressive lengthening of the posterior corpuscles as the animal ages, apparently by the addition of new glomeruli posteriorly. Bowman's capsule surrounds a single loop and consists of parietal and visceral layers which are similar to those seen in higher vertebrates.The kidney of the adult has a single complex renal corpuscle which extends almost its entire length. Present evidence indicates that the adult kidney is formed during transformation and that the larval renal corpuscles do not contribute to the single elongate corpuscle of the adult. A large number of lobed glomeruli, lying one behind the other, form the elongate glomus. Interposed between each pair of lobes is the dilated end of a nephron. There are no typical Bowman's capsules in the adult although where these nephric capsules invest the blood vessels of a lobe they develop podocytes similar to those of the visceral layer of Bowman's capsule and elsewhere they consist of a simple squamous epithelium similar to that of the parietal layer.
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  • 24
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Morphogenesis of the retina of the Sprague-Dawley albino rat was studied by light microscopy from day 11 of gestation until 225 days after birth. A quantitative analysis during development of retinal volume, thickness of the entire neural retina and thickness of each of the retinal layers, both posteriorly and peripherally, was made. The results indicate that initially a single neuroblastic layer forms and continually thickens by mitosis at its outer border. The retinal layers then form in sequence, moving from the inner retinal border outward and always beginning posteriorly and then spreading peripherally. The transient layer of Chievitz does not appear. All adult layers are present by eight days after birth and each layer thins after reaching its maximal thickness. Total thickness of the retina excluding pigmented epithelium, is greatest on postnatal day 5, but retinal volume only reaches a peak on postnatal days 7 to 12. The nerve fiber, inner plexiform, outer plexiform and bacillary layers all continue to increase in thickness after the ganglion cell and inner and outer nuclear layers reach their maximal width and are beginning to become thinner.
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  • 25
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 127 (1970), S. 357-367 
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: This study deals with the postnatal growth and remodeling changes that take place in the cranial bone of Macaca mulatta. Multiple ground sections were prepared throughout each component bone from the calvaria and cranial floor of young, rapidly growing specimens having primary or mixed dentition. These sections were then analyzed for (1) the different types of inward-growing and outward-growing bone tissues present, and (2) the distribution of resorptive and depository periosteal and endosteal surfaces. Using this information, the remodeling history of each bone was reconstructed and the overall growth pattern of the craninum as a whole was determined. The growth changes that characterize the brain case of the monkey were then compared and contrasted with those in Homo. While a number of distinct similarities were observed in their respective growth and remodeling processes, several marked differences were also found. These occurred largely in certain parts of the cranial floor and they appeared to be associated with corresponding differences in the size, configuration, and disposition of the brain in the two species and also with factors related to body posture and facial prognathism.
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  • 26
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The structure of the guinea pig visceral yolk sac from 26 days of gestation to term was studied by transmission and scanning electron microscopy. Particular emphasis was placed on the columnar endoderm cells of the villous portion of the yolk sac. The apical cytoplasm of the endoderm cells contained numerous membrane invaginations, endocytic vesicles, dense tubules and large vacuoles which appeared to form an interrelated absorptive system. The saccular invaginations of the apical cell membrane were specialized by the development of both an amorphous extracellular coat and an internal coat. Both the endocytic vesicles and dense tubules were thought to be derived from the saccular invaginations following detachment of the latter from the cell surface  -  the endocytic vesicles forming by fusion of saccules creating progressively larger structures, and the dense apical tubules forming by a process involving fluid loss from the saccules. Large vacuoles were present deeper in the apical cytoplasm; these probably were formed by fusion of smaller vesicles. The supranuclear cytoplasm contained numerous dense droplets and a Golgi zone. The possible relationships of the droplets to the vacuoles was discussed.
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  • 27
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 127 (1970), S. 423-435 
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The avian kidney is composed of cortical and medullary lobules, with the former surrounding branches of the renal vein. Cortical lobule diameters varied intraspecifically according to level of association with the venous system, and interspecifically were greatest in nonpasserines. All cortical tissue examined contained maculae densae.Each medullary lobule receives collecting ducts and loops of Henle from several cortical lobules. Such a complex may be viewed as a lobe, and the entire kidney as multilobar. The relative diameter of a medullary lobule appears directly related to the number of cortical units with which it is associated. Distally, most lobules vary from 0.3 to 0.5 mm in diameter, and contain 20 to 30 collecting ducts. The latter fuse dendritically as they traverse a medullary unit, and eventually form ureteral branches which drain directly into the ureter.Intramedullary organization in passerines involves aggregated thin limbs bounded by collecting ducts which in turn are surrounded by uneven layers of thick limbs. While some nonpasserines approach this pattern, others lack apparent organization of intramedullary elements. The turn of Henle's loop was restricted to the thick limb in all birds examined. Avian and mammalian thick limbs are similar in diameter, but avian thin limbs are typically wider.Small kidneys have short ureteral branches with primary stems clustered in each kidney division. In larger kidneys, where medullary lobules are often remote from the ureter, ureteral branches are long and not clustered.
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  • 28
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Regeneration of the gastrocnemius muscle from minced transplanted muscle fragments was studied in 46 rats. The jumping complex of muscles (gastrocnemius, soleus and plantaris) was removed from the donor and minced into 1 mm3 fragments. In one experimental series minced muscle was orthotopically implanted into sibling animals, and in the other series minced muscle was implanted into non-sibling animals of the same strain. During the first week after implantation, regenerative activity in the homotransplanted muscle fragments was intense and did not differ histologically from that occurring in autotransplanted muscle. Staritng in the second week, areas of regenerating homotransplanted muscle fibers became infiltrated with small lymphocytes. Despite relatively massive cellular rejection in the regenerates, individual skeletal muscle fibers regenerated to maturity. Regenerates from homotransplanted muscles often attained the same gross from as regenerates from auto-transplanted material, but in no case was the amount of muscle fibers in homografted regenerates greater than 50% of that seen in regenerates arising from autografted muscle fragments. About half of the advanced regenerates were reduced to broad bands of connective tissue containing no muscle fibers.
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  • 29
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Chick embryos of graded ages, ranging from freshly laid eggs to one week incubation, were prepared for electron microscopy.Interstitial bodies are expressions of “ground substance” that resemble structureless masses of cytoplasm without enclosing plasmalemma. They measure from 0.1 to ca. 1 μ in diameter. Toward the end of the first day of incubation they are found in the tissue space near to or in contact with the ectodermal boundary (basement) membrane. They seem to contribute to its increasing amorphous component. Microfibrils first appear close to or in contact with the ectodermal boundary membrane and are similarly related to interstitial bodies. At 44 hours interstitial bodies are especially numerous where the neural tube is separating from the ectoderm. Here boundary membranes have become intermittent and interstitial bodies appear to contribute to their repair. By the fourth day interstitial bodies are less numerous. Many appear to break up. Their edges tend to become dispersed into clouds of finely granular material, especially in areas of the tissue space occupied by wisps of microfibrils. The close association of amorphous ground substance and extracellular fibrils persists indefinitely.
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  • 30
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The choroid plexus was studied in 217 necropsy specimens from human beings two months to 94 years of age. With advancing age, the height of the cuboidal epithelial cell gradually decreases, many becoming squamous. Cytoplasmic vacuoles increase in number. Focal stratification is not an artefact, and is evidence of proliferation. The proliferated cells eventually desquamate, becoming round, large and foamy as they accumulate intracytoplasmic lipid and degenerate. The findings indicate that cellular desquamation occurs during life. Filaments of mucopolysac-charides are common in the choroid plexus of old people. Stromal alterations associated with increased age consist of a gradual increase in the amount of connective tissue, in number of meningocytes and psammoma bodies, and in severity of hyalinization, fibrosis, fragmentation of connective tissue fibers and calcification. Most psammoma bodies are found in the glomus choroideum. Non-lamellar calcific foci occur mainly in the matrix of the choroidal villi and fronds. Formation of psammoma bodies is associated closely with the meningocytic whorls. Lipids, mucopolysaccharides and mucins are identified in both epithelial and stromal components of the choroid plexus. Lipids appear in the stroma later in life. It is suggested that lipid in the cytoplasm of desquamated choroidal eipthelial cells is one source of lipids in the cerebrospinal fluid.
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  • 31
    Electronic Resource
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    New York, NY [u.a.] : Wiley-Blackwell
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
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  • 32
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: This study was conducted to determine if there is a greater variation in fetal weight and/or placental weight among litters of rat fetuses than within a single litter. Three hundred and twenty-seven litters comprising 1,979 fetal and placental weights were analyzed using analysis of variance within versus among litters. There was a definite litter effect, i.e., variation in fetal and placental weight was greater (p 〈 0.05) among litters than within litters. The variation in fetal and placental weights between litters became greater with increasing litter size. Experimentally limiting the litter size early in gestation does not reduce or eliminate the litter effect. This litter effect means that individual fetuses from several rat pregnancies cannot be considered to have come from a common universe and, therefore, the number of litters and their mean growth data are much more meaningful than the number of embryos in an experiment. When designing research programs in which embryonic and placental growth in rats are to be evaluated, it is more important to establish the experimental goal on the basis of the total number of litters rather than the total number of embryos per experimental or control group.
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  • 33
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A comparative study of the hemopoietic tissues and blood of non-pregnant and pregnant rats of graded duration of gestation was undertaken and the results were compared with those obtained on postsplenectomized rats at similar stages of pregnancy. The number of megakaryocytes was determined in representative fields of the liver, spleen and bone marrow. Platelet counts were performed on blood collected from the venae cavae of these rats using a modified Rees-Ecker technique.The liver of normal adult animals, pregnant or non-pregnant, does not reveal megakaryocyte production. Although bone marrow is the most active site of megakaryocytopoiesis in the adult animal there is only a slight numerical increase in megakaryocytes during pregnancy. The most dramatic change occurs in the spleen of the pregnant rats and is reflected by increased splenic weight and increases in red pulp and in the number of platelets circulating in venous blood. Splenectomy of the rat produces an abrupt increase in the number of circualting platelets which is not sustained into the later postoperative period when platelet counts below those of control animals are found. When pregnancy occurs in the later postoperative period, the splenectomized rat develops a trend toward increased platelt counts but these never reach the level obtained in nonsplenectomized pregnant rats.
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  • 34
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: In analyzing the anatomy and physiology of sensory systems it is often necessary that one activate the particular system being studied with appropriate stimulation. In experiments where this is necessary, the stimulation presented should be specific to the sensory system under study. With the pain system, however, this is most difficult since most stimuli that activate pain pathways also activate other pathways such as those that mediate touch and pressure sensations. It is also helpful to have available a stimulation technique that can be used in both acute experiments and long term neurophysiological and behavioral experiments. For investigation of the anatomical substrates of pain perception, a technique has been developed for implantation of bipolar electrodes in the teeth of cats that permits one to stimulate the tooth pulp in acute or chronic preparations, and, thus, to activate a pain pathway exclusively and directly. This technique provides a stimulus that is readily quantifiable, easily controlled, entirely nociceptive in character, and which can be used in a wide variety of situations.
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  • 35
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    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 128 (1970), S. 265-281 
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: In the normal adult rat testis, type A0 spermatogonia do not appear to participate to a significant extent in the production of spermatocytes, while type A1 spermatogonia periodically initiate a series of divisions resulting in the production of spermatocytes and new type A1 spermatogonia.The behavior of type A0 and A1 spermatogonia was investigated following administration of a single dose of x-rays (300 r) to the testis. Using whole mounts of seminiferous tubules, the type A0 and A1 cells were counted at various intervals after irradiation. At 8 and 13 days after irradiation, type A1 spermatogonia reached lowest values, i.e., 6% and 3% of non-irradiated control, while type A0 reached the lowest value, i.e., 62% of control at eight days. Thereafter the numbers of type A0 and A1 progressively increased to return to normal at 39 days. It was thus concluded that the type A0 were comparatively more resistant to x-irradiation than type A1 spermatogonia.To verify if the surviving type A0 proliferated in the irradiated testis, animals were injected with 3H-thymidine three hours before they were sacrificed at various times after x-irradiation. In irradiated testes the labeling indices of the surviving type A (A0, A1-A4) were the same as in the non-irradiated testes except in stages V-VI of the cycle of the seminiferous epithelium. While in the controls only 2% of type A cells were labeled at these two stages of the cycle, after irradiation the labeling index of type A reached a maximum of 31% at 13 days to return to control values by 39 days. Since at 13 days after irradiation type A0 spermatogonia were the predominant component of the spermatogonial population, it was concluded that these cells must have incorporated 3H-thymidine and thereby contributed to the reconstruction of the spermatogonial population partially destroyed by irradiation.
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  • 36
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    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 128 (1970), S. 341-357 
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The occurrence of striated muscle in an “extralobar pulmonary sequestration,” a typical “accessory lobe,” has been described for the first time in an infant with the respiratory distress syndrome of the newborn. The few published cases of the presence of striated muscle in the lungs have been reviewed. In most instances they were associated with benign or malignant tumor formation. The simultaneous occurrence of a pulmonary sequestration and striated muscle is explained by postulating the displacement of a fragment from the lung bud early in its development. This view eliminates the necessity of invoking an additional pathological happening in the sequestrated lung in the form of a “metaplastic transformation” of either smooth muscle or embryonic connective tissue into striated muscle. While a heteroplastic transformation may occur in instances of malignant tumor formation, striated muscle in the developmental anomaly described here may well form on an entirely different basis.
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  • 37
    Electronic Resource
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    New York, NY [u.a.] : Wiley-Blackwell
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
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  • 38
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    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 128 (1970), S. 429-461 
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Hamster eggs freed from the cumulus oophorus and zona pellucida were inseminated in vitro with capacitated spermatozoa. As soon as the spermatozoon reaches the surface of the egg cytoplasm, numerous microvilli of the egg surround the spermatozoon. Those microvilli attached to the acrosomal collar region of the spermatozoon quickly spread over the inner acrosomal membrane of this region, dislodging the outer acrosomal membrane and the overlying sperm plasma membrane. At the same time, microvilli fuse with the plasma membrane of the postnuclear cap region of the spermatozoon, and the egg cytoplasm quickly flows around the nucleus of that region of the spermatozoon. The inner acrosomal membrane persisting on the sperm head never fuses with the egg (microvillar) plasma membrane. This membrane is destined to disintegrate and be absorbed into the egg cytoplasm. Incorporation of the sperm flagellum into the egg cytoplasm takes place by fusion between plasma membranes of the spermatozoon and egg.
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  • 39
    Electronic Resource
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    New York, NY [u.a.] : Wiley-Blackwell
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
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  • 40
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Serial sections of human embryos and fetuses reveal that the sacral nerves which contribute fibers to the pelvic plexus often have dorsal, ventral, and oblique communicating rami. The ventral rami resemble the white rami of upper thoracic nerves and some of their fibers pass close by or through the chain ganglia and into the pelvic plexus. The sizes of the ventral rami are often in inverse proportion to that of the pelvic splanchnic nerves. That is, when the pelvic splanchnic nerves are poorly developed, the ventral rami are large, and conversely, when the pelvic splanchnic nevers are well developed, these rami are small. The pelvic plexus was found to receive fibers from the sympathetic trunk and its ganglia in addition to those from the hypogastric plexus and the pelvic splanchnic nerves.Analysis of the observations made in this study together with a review of the literature in light of the present day classification of nerve fibers raises serious doubts concerning the limits set for the outflow of preganglionic nerve fibers from the spinal cord and the distribution of gray and white rami as described in recent textbooks in terms of their histological and physiological significance.Nerve fibers from the pelvic plexus can be traced along the walls of the bladder and the urachus and along the umbilical arteries into the umbilical cord. In embryos, only a few scattered nerve fibers were found distal to the umbilicus, but in fetuses at term, distinct nerve bundles were identified in the cord. These bundles sent branches to the walls of the umbilical arteries; other branches terminated as “end-nets” in Wharton's jelly. These nets appeared as fine fibers with nodular swellings at irregular intervals. Innervation of the umbilical arteries was richest within the first few inches of the cord. Beyond this region, the nerves rapidly decreased in number. “End-nets” were present as far as four inches from the umbilicus. Granular cells resembling Langerhans' cells were found in the cord. Often these cells were closely associated with fine nerve fibers.
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  • 41
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    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 129 (1970), S. 21-39 
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Satellite cells, rarely seen on normal muscle fibers, are located between the sarcolemma and the basement membrane of a muscle fiber. Limb muscles and the extraocular muscles of adult guinea pigs were denervated and studied from two to seven days after operation. Satellite cells are now frequently seen. A nucleus surrounded by a small amount of cytoplasm separates from a denervated muscle fiber and forms a satellite cell. A series of clefts and membranes forms in the periphery of the muscle fiber to make separation channels and pinch off the muscle cell nucleus and its cytoplasm from the parent fiber. This cell, now called a satellite cell bud, can be seen in the process of splitting off from the parent muscle fiber, with portions of the same cell separated from and still part of the muscle fiber. The sacs of endoplasmic reticulum in the satellite cell bud dilate markedly. Centrioles and a cilium form in the satellite cell bud. The bud elongates, and concentrations of ribosomes and polyribosomes appear in its cytoplasm. Small points of contact, with membrane thickenings, between bud and parent fiber allow the elongating bud to be kept longitudinally oriented under the basement membrane of its parent fiber. Muscle filaments form in the elongating bud, which is now a myoblast. Hence, satellite cells arise from portions of denervated muscle fibers themselves, elongate, and become myoblasts.
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  • 42
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    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 129 (1970), S. 65-87 
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Subauricular and rump glands of pronghorns (Antilocapra americana) collected during every month of the year, were examined histologically. In early spring the apocrine and sebaceous zones of the paired subauricular glands, which are found only in males, proliferate abruptly. These zones continue to enlarge and become highly secretory during the summer; they regress during the fall and are quiescent in December. During the peak of activity large sebaceous storage vesicles are present and copious amounts of secretory material occupy the apocrine lumina. Irregular clumps of cells that are associated with the apocrine tubules are numerous in summer and appear to be associated with apocrine secretory activity. The subauricular glands of castrated bucks are small and inactive compared to normal glands. Annual proliferation and regression of the subauricular glands follows similar activities of the testes. Thus, the cycle of activity in these glands is apparently controlled by gonadal hormones. Odors from the subauricular glands may serve for sex recognition, stimulation, and marking of territories. The paired rump glands consist of lobulated sebaceous units and coiled apocrine tubules that maintain limited secretory activity throughout the year. Contraction of large arrector pili muscles associated with hairs in the glands may cause accelerated secretion. The rump glands of normal males, females, and castrated males, are similar in all respects. Apparently these glands are not sexually influenced. The rump glands may serve for olfactory warnings in conjunction with the visual warnings of the white rump patch.
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  • 43
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Locomotor capability on smooth vertical surfaces is rare in mammals. The adhesive discs on thumbs and soles of bats of the family Thyropteridae are uniquely specialized for this purpose, but their functional organization remains virtually unexplored. The face of the discs is concave, has a characteristic dermatoglyphic pattern, and is permanently moist. Each disc is supported by a biconcaval fibrocartilagenous framework; its circular “rim” is divided into 60-80 chambers, each accommodating a sudoriparous gland which discharges on the disc face. Glandular form and cytology are unique, reflecting special functional adaptations. Other significant adaptations involve the epidermis, distribution of adipose tissue, extrinsic muscle insertions, disc relations to digital joints, and distribution of certain sensory endings. The discs have no intrinsic musculature and are manipulated from without. Experiments with living Thyroptera and analysis of the internal organization of the discs verify that their functional mode is suctorial rather than some other adhesive mechanisms; special relationships within the thumb discs suggest that the adhesive force may be to some extent adjustable under normal use.
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  • 44
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    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 129 (1970), S. 177-191 
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The chromatoid body of rat spermatocytes and spermatids was studied with routine electron microscopy and the PA-silver method for detection of glycoproteins. The chromatoid body consists of a membrane-free aggregate of electron dense, finely filamentous material, in association with small vesicles. In late pachytene spermatocytes, there may be more than one chromatoid body; its dense component is diffusely reticulated. In young spermatids, there is only one chromatoid body per cell; the dense component is fairly compact, but it encloses less dense areas continuous with the cytoplasm. Within the less dense areas, as well as at the periphery of the dense component, small (400-800 Å) oval or tubular vesicular structures are observed whose contents exhibit a positive reaction for glycoprotein in PA-silver stained sections. When the spermatid nucleus begins to elongate, the chromatoid body takes the form of an arc around the axial filament proximal to the centriolar apparatus. Soon thereafter, the bulk of the chromatoid body condenses into a sphere of very dense filamentous material surrounded by a corona of enlarged glycoprotein-containing vesicles. In the later stages of spermiogenesis, the chromatoid body migrates away from the nucleus and disintegrates by fragmentation. It is noted that the chromatoid body undergoes its major morphological changes, possibly indicative of its active phase, while located in the para-centriolar region, at the time when the nucleus elongates, and the connecting piece and ring of the spermatid are formed.
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  • 45
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The fate of heterologous, isologous and homologous ferritin-I125 injected into rat footpads was compared by determination of radioactivity in sera and organs, and by radioautography and electron microscopy. The clearance of heterologous ferritin-I125 from circulation was significantly faster than that of isologous or homologous ferritin-I125. This was supported by measurement of radioactivity in various organs, and by radioautography and electron microscopy of popliteal lymph nodes which reveled structural details of macrophages undergoing antigen uptake.These observations permit the following conclusions. (1) In most reticuloendothelial cells there is some nonspecific pinocytosis of antigen which is not related to immunogenicity. (2) The induction of massive immunologically specific pinocytosis by macrophages may be due to specific antigen recognition by receptors located at the cell surface. (3) Heterologous ferritin ingested by macrophages are mostly found in vacuoles or scattered in the ground cytoplasm. However, some appear in the nucleoplasm, usually in association with loose strands of chromatin materials. (4) Ferritin molecules are conspicuously absent from mitochondria, the rough-surfaced endoplasmic reticulum and Golgi apparatus. (5) The fiber-associated reticular cells of the primary nodule and germinal centers may correspond to “dendritic reticular cells” or “dendritic macrophages,” capable of long-term retention of antigens.
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  • 46
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The cytological basis for protein transport across the guinea pig visceral yolk sac at 36-44 days of gestation was studied by means of electron microscopy following injection of horseradish peroxidase and ferritin. These results were compared with those obtained after administration of colloidal thorium dioxide. Distribution of the tracer molecules was studied at 2, 10, 20, 40, and 160 minutes after injection into the uterine lumen. All three tracer molecules were rapidly absorbed by endoderm cells. Although most of the protein appeared to be retained in droplets in endoderm cells, some protein was transmitted. Peroxidase was found to be rapidly transmitted across the yolk sac, ferritin somewhat more slowly, and colloidal thorium was not transmitted at all. Protein which had exited from the endoderm cells followed any of three pathways: (1) it crossed the visceral basement membrane and entered the vitelline capillaries; (2) it crossed the mesodermal compartment, crossed the mesothelial cells and entered the exocoelomic cavity; or (3) some of the protein was sequestered by macrophages in the splanchnic mesoderm. The pathways observed are consistent with those suggested by previous authors for the passage of maternal antibodies and serum proteins to the guinea pig fetus.
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  • 47
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    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 166 (1970), S. 541-555 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Morphologically the oviduct of the frog, Rana pipiens, consists of a lining epithelium and tubular jelly-secreting glands. The oviduct can be divided into six regions (designated R1 anteriorly - R6 posteriorly) based on the differential staining of the jelly glands. The regions measured 1, 5, 6, 3, 20 and 3 cm, respectively. These regions correspond to 6 histochemically distinct layers of jelly (designated J1 nearest the egg through J6 farthest from the egg) which are deposited around the egg during the egg's sojourn in the oviduct. A correlation between lengths of each oviducal region and thickness of individual jelly layers was observed. That is, J5 is the thickest, followed by J3, 2, 6, 4 and J1 which is thinnest.Histochemical properties of jelly glands and corresponding jelly layers were essentially the same in the tests performed. All regions and layers except R5 and J5 contain a large amount of acid mucopolysaccharide and the mucopolysaccharide in R and J1, 3 and 4 is sulfated. Neutral mucopolysaccharide is present in R2, J2, R5 and J5. Although protein is present in all layers and oviducal regions it was found in higher concentration in R and J1, 3 and 6 and in lowest concentration in R and J2.
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  • 48
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A surface planimeter was used to assess tetracycline-labelled areas of undecalcified sections of the maxillas of 16 male guinea pigs. In three different molar regions studied, highest values were found in the last-molar region, followed by the first-molar and second-molar region. In the 32-42 day old animals the values in the incisal region were higher than in the first-and-second-molar region, but lower than in the last-molar region. In the age groups of 47-57 and 62-67 days, proportions of labelled bone in the incisal regions were lower than those found in the first-molar and last-molar regions, but approached the level of those found in the second-molar region. There were statistically significant age-associated differences and varying amounts of labelled bone in different areas.
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  • 49
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    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 166 (1970), S. 605-609 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Endothelial fenestrations have been observed in the venules of the large salivary glands of mice. The structure of the fenestrations is similar to those of capillaries. The fenestrations are frequently demonstrated in the endothelium of the transitional portions from a capillary to a venule. They are also seen in overlapping thin cytoplasm located on either the blood or tissue front of the endothelial cells of the venules at cell junctions.
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  • 50
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    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 166 (1970), S. 627-633 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A C-shaped bar of hyalin cartilage was present in the fibrous tissue around the aortic orifice in the heart of all 70 male and 10 female Syrian hamsters, 103 to 843 days old. This cartilage has the same cellular and intercellular characteristics as the tracheal cartilages. Fibers from four of the six lunulae of the semilunar aortic valves, the aortic sinuses and vestibule, and cardiac muscle adjacent to the posterior semilunar valve insert onto the fibrous capsule and the protuberances of the aortic cartilage. A few fibers from the ventricular and interatrial septa and the aortic cusp of the mitral valves are also attached to the fibrous capsule. Cartilage did not occur around the pulmonary orifice or in other regions of the heart with the exception of a chondroma in the aortic valve. The C-shaped aortic cartilage in this hibernating species is discussed in relation to its possible significance in preventing collapse of the aortic orifice and the possibility of increasing coronary blood flow.
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  • 51
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 166 (1970), S. 635-657 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The formation of peribiliary dense bodies in developing rat liver was studied by electron microscopy. Dense bodies arise in close conjunction with an extensive Golgi apparatus which displays acid phosphatase, inosine diphosphatase and thiamine pyrophosphatase activity throughout development. The position of these enzymes within the Golgi apparatus appears somewhat variable. Dense bodies are present by the thirteenth day of development and gradually increase in number. They show acid phosphatase activity from their earliest appearance. These findings demonstrate that: (1) peribiliary dense bodies are lysosomal from their earliest appearance; (2) they apparently arise directly from a well-developed Golgi apparatus; and (3) the Golgi apparatus contains several enzymes simultaneously, suggesting that it becomes multifunctional at an early stage of development.
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  • 52
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 167 (1970) 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 53
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Placental villi were obtained from monkeys at the Wisconsin Primate Research Center during 50-150 days gestation. As in the human, the villi consist of a vascular mesenchymal core surrounded by inner cytotrophoblastic and outer syncytiotrophoblastic layers.The syncytiotrophoblast contains abundant rough endoplasmic reticulum and a well developed Golgi complex consisting of stacked lamellae and diffuse vesicles. An asymmetrical distribution of ribosomes occurs on RER cisternae associated with mitochondria. Branched microvilli frequently bear dilated tips and resemble stereocilia. Cytoplasmic tufts and microvilli increase the surface area, and the base of the tuft usually contains a large membrane-bound vacuole with a flocculent inclusion of low electron density. These vacuoles are lacking after 100 days. In later stages the syncytiotrophoblast bears irregular microvillous processes and specialized attachment sites at its contact with the basal lamina.Hofbauer cells in the villus core contain numerous large vacuoles, coated pinocytotic vesicles and smooth vesicles apparently derived from ER; the latter are sometimes fused to the large vacuoles. Hofbauer cells appear to be derived from undifferentiated mesenchymal cells.
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  • 54
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Cilia-bearing cells have been observed near the bottom of the crypt of the human circumvallate papilla, between the lower taste buds and the duct of von Ebner's gland. It is likely that they serve one or more of the following functions: cleansing the papillary crypt, circulation of tastants, and bathing the pores of the taste bud in the various fluid secretions of the oral cavity.The kinetosomes of these cells were observed to possess typical transitional fibers and rootlets with periodic structure. In addition, a single, lateral, satellite-like projection from the midregion of the kinetosome was connected to microtubules which coursed deeply with the mitochondria-rich cytoplasm as did fine fibrils and some rootlets.
    Additional Material: 7 Ill.
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  • 55
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Large and small laminated cytoplasmic bodies are reported in neurons and dendrites of the ventrobasal and posterior (PO) nuclear groups of the thalamus of the cat. The bodies are more frequently seen in dendritic profiles than in nerve cell bodies. They differ in size, as well as in number and complexity of orientation of the constituent tubules. Their topographic relationship to endoplasmic reticulum, synapses and adhesion plaques is noted and their possible evolution is discussed.A single collection of annulate lamellae is described in the perinuclear soma of one neuron.
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  • 56
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 167 (1970), S. 197-204 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: An extensive vascular arrangement resembling erectile tissue is described in the tongue of an anteating Monotreme, the Echidna. Its possible function as a stiffening mechanism is discussed in relation to observations on living animals.
    Additional Material: 1 Ill.
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  • 57
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The distribution of catecholamine and acetylcholinesterase containing nerve fibers in the rat lung was studied employing specific histochemical techniques. Silver impregnation and methylene blue staining was used to allow comparison with the results of previous workers. Catecholamine containing nerve fibers were found associated with the nerve plexus about bronchial arteries and were carried to the bronchial wall and the pulmonary vessel wall along branches of the artery. Acetylcholinesterase containing fibers followed along the bronchi and bronchioles and were found in the adventitia, mucosa and submucosa, Acetylcholinesterase containing nerves were not found in the perivascular plexi with the exception of a few positive nerve fibers within the larger pulmonary veins.
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  • 58
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 167 (1970), S. 225-230 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: When pseudopregnant hamsters were ovariectomized and their uteri traumatized on day 4, deciduomal growth (not significantly different from that seen in intact controls) could be maintained by daily injections of 1, 2 or 4 mg of progesterone either alone or in combination with 1, 2 or 5 μg of estrone. When ovariectomy was performed on day 1 of pseudopregnancy and uterine traumatization on day 4, induction and maintenance of a deciduomal response could be achieved with 1 or 2 mg/day of progesterone alone (or in some cases in combination with 1 μg/day of estrone) from days 1 to 3 followed by 1 or 2 mg/day of progesterone in combination with 1, 2 or 5 μg/day of estrone from days 4 to 7. The best results were obtained with progesterone alone (2 mg/day) before trauma and estrone (2 μg/day) and progesterone (2 mg/day) after trauma.
    Additional Material: 2 Tab.
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  • 59
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: In order to compare the morphologic response of white and brown fat to various hormones in vitro the technique of organ culture was used in this study. Explants of white and brown fat from young mice fasted for 48 hours were exposed to culture media supplemented with insulin, thyroxin or cortisol. Morphologic changes due to these hormones were studied by means of histologic analyses and cell width measurements. Insulin acted to increase the size of cells and intracellular lipid content of brown and white fat explants when compared to similar explants exposed to unsupplemented media. Brown fat explants reacted earlier than white fat in this case. Thyroxin or cortisol alone had no influence on cell width or intracellular lipid content of these tissues. With the combination of insulin and thyroxin only white fat cells showed a greater increase in lipid deposition than that seen with insulin alone. No significant changes were noted when the combination of insulin and cortisol, or when all three hormones were added to the culture medium compared to that seen with insulin alone. The conclusion reached confirms those of other authors that brown and white fat possess enough dissimilarities to be classified as two different types of tissue.
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  • 60
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 167 (1970) 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 61
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Cytological investigation of Hofbauer cells in various stages of gestation reveals that they are similar to normal macrophages except for unusually large cytoplasmic flanges and included vacuoles. The system of vacuoles is apparently the result of macropinocytotic activity. The individual vacuoles undergo asymmetrical collapse in regions adjacent to small juxtavacuolar tubules thought to be derived from the agranular endoplasmic reticulum. In addition, coated micropinocytotic vesicles are common. Hofbauer cells thus appear to be a type of macrophage with an unusual capacity for fluid ingestion. In younger placentas, Hofbauer cells are usually associated with extracellular compartments within the stroma. These compartments are relatively free of collagen fibrils and demonstrable ground substance and are clearly demarcated from the rest of the stroma by processes of fibroblasts. The abundance of these cells in early placentas, their location in the stroma, and evidence of their pinocytotic activity suggest that these cells may play a role in removal of proteins from interstitial fluid. Hofbauer-like cells were also studied in the guinea pig and the little brown bat. Of these two species, the Hofbauer-like cells of the bat more closely resemble human Hofbauer cells in that they show evidence of extensive macropinocytotic activity.
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  • 62
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 167 (1970), S. 253-275 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: This sequence of electron micrographs shows the progressive changes undergone by the dispersed chromosomal fibrils of the interphase nucleus as they begin to condense, in early prophase, into clumps centered on three types of small nuclear structures. These bodies do not seem to have been described previously in detail in connection with mitosis, although they were mentioned as a group in a preliminary note by Bloom (1963). In the present report they are divided into three groups indicated as F1, F2 and F3 and are labelled 1, 2 or 3 in the accompanying electron micrographs.The clumps enlarge by continued accretion of more and more fibrils concentrated about these three types of bodies until the chromosomes of metaphase are formed. The inference that the bodies depicted here form focal points for the condensation of dispersed chromosomal filaments rests solely on the repeated finding of the progressive aggregation of the fibrils about them. Further studies are in progress on factors mediating these changes and on the nature of the F bodies.
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  • 63
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 167 (1970), S. 277-289 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The alveolar macrophage of the cat shares some features with the alveolar macrophages of ordinary laboratory mammals and man, mainly a voluminous Golgi zone exhibiting evidence of secretory activity. The very numerous typical lysosomes appear to be a secretory end product. They increase in size by a fusion process. At some stage of this process dense periodic structures, crystal-like, become visible in intermediate size lysosomes, which later form heterogeneous crystal-like granules characteristic of the cat's alveolar macrophage.The crystal-like granules are bounded by a unit-membrane pattern and contain a dense periodic parallel lamellar material (crystal-like) mixed with fluffy amorphous substance and surrounded by a clear homogeneous material. Based on its structure as observed at a high magnification, and its behavior during phagocytosis, this crystal-like material appears to be composed of lipid.Intra-pulmonary injection of red blood cells was carried out in order to observe the fate of the crystal-like granules during phagocytosis as compared to that of typical lysosomes. Like typical lysosomes the crystal-like granules become reduced in number and undergo incorporation to the phagocytic vacuoles, demonstrating their lysosomal nature.
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  • 64
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    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 167 (1970), S. 291-301 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A relatively well developed prostrate is the only accessory sex gland present in the spotted skunk (Spilogale putorius). The distal end of the vas deferens is quite glandular, but there is no distinct ampullary swelling. The gross morphology of this species is compared with that of several other members of the family Mustelidae.
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  • 65
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 167 (1970), S. 303-308 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Microtubules have been described to occur frequently within the subpial fibrous astrocytes of the adult spinal cord of three species. This finding is related directly to perfusion fixation by glutaraldehyde. Immersion fixation produced no or fewer tubules in this area. It is suggested that the presence of microtubules in these cells might reflect a specific skeletal function. Astrocytes from other locations within the central nervous system displayed fewer microtubules within their cytoplasm.
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  • 66
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Light and electron microscopy of the carotid body of the Weddell seal shows two types of cells, the main and the sustentacular cells.The main cells contain dense osmiophilic granules in variable amount. Their cytoplasma shows either a high or a low electron density. On this basis light and dark main cells were distinguished.The differences in cytoplasm electron density and the great variability in the number of granules were interpreted as expressions of different stages in a process of secretory nature.A very rich innervation with outstanding nerve endings was observed in the carotid body of the Weddell seal. This picture is similar to that observed in stimulated carotid bodies. The carotid body of the Weddell seal a marine mammal that stays underwater for a long stretch of time, may be considered as subjected to frequent stimulations.
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  • 67
    Electronic Resource
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    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 167 (1970), S. 371-377