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  • Articles  (62)
  • DKFZ Publication Database
  • human
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  • 1985-1989  (62)
  • 1
    ISSN: 1420-9071
    Keywords: Dopamine ; vasorelaxation ; human ; pulmonary arteries ; DA1 receptors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Dose-dependent relaxations were induced by dopamine in human pulmonary arteries that had been contracted with prostaglandin F2α without α-adrenergic blocking agents. The dopamine-induced relaxation was inhibited by haloperidol and fluphenazine, but not by domperidone, suggesting that this relaxation was mediated via DA1 receptors.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Pharmaceutical research 6 (1989), S. 1-3 
    ISSN: 1573-904X
    Keywords: benzodiazepines ; animals ; plants ; human ; natural drugs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Three research groups have provided evidence that benzodiazepines might be also of natural origin. In the brain of different species including humans and in several plant products, desmethyldiazepam and diazepam are detectable by immunological methods and gas chromatography—mass spectrometry. Thus, benzodiazepines represent natural drugs which may be incorporated into animals and humans through plant products. Whether the measured low concentrations (ranging from 0.01 up to 600 ng/g wet weight) have any biological role or clinical significance remains to be determined.
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Clinical Anatomy 2 (1989), S. 63-67 
    ISSN: 0897-3806
    Keywords: osteology ; sacrum ; ilium ; human ; Life and Medical Sciences ; Miscellaneous Medical
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: To investigate sex differences in the morphology of the auricular surfaces of the human sacroiliac joint, 153 dried bone sets of unknown ages, and of Indian origin were studied, and various measurements were made of the corresponding iliac and sacral auricular surfaces. Some significant differences. The sacral and iliac auricular surfaces was larger and longer in males. The most prominent point on the ventral border of the iliac auricular surface was situated more caudally in females. The iliac angle was larger in males. The deepest point of the dorsal border of the iliac auricular surface was more caudal in females.
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  • 4
    ISSN: 1573-7330
    Keywords: egg yolk ; human ; spermatozoa ; oocyte
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Penetration of zona-free hamster oocytes by human spermatozoa after preincubation with BWW medium (standard technique) or a buffer system containing egg yolk (TESTY) was compared by applying both treatments to aliquots of 60 ejaculates from 34 patients. The TESTY-treated spermatozoa penetrated the oocytes much more successfully than the spermatozoa treated by the standard technique. Although the penetration levels achieved by the two methods were significantly correlated, the correlation coefficient was too low to predict the penetration outcome from one technique to the other. More consistent results were obtained when different ejaculates from the same donor were treated by TESTY than by the standard technique. Spermatozoan penetrating ability was more strongly correlated with sperm concentration, motility, and morphology after treatment by the standard technique than after TESTY treatment. Much larger differences in penetration were present between normal and abnormal ejaculates when the standard technique was used than TESTY.
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  • 5
    ISSN: 1573-4919
    Keywords: triosephosphate isomerase ; cell proliferation ; isozymes ; mRNA ; primate ; human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Summary Three primary isoforms of the dimeric glycolytic enzyme, triosephosphate isomerase (TPI; EC 5.3.1.1), are detected in proliferating human cells. The electrophoretically separable isoforms result from the three possible combinations of constitutive subunits and subunits expressed only in proliferating cells. Only a single primary isoform is observed in quiescent cells. The two subunits, which differ by covalent modification (s), are products of the single structural locus for this enzyme. Expression of the proliferation specific subunit (TPI-2) is detected within 6–10 hr following mitogen stimulation of quiescent human cells, requires RNA synthesis and is inhibited by agents which inhibit interleukin 2 expression or function. Only the constitutive subunit (TPI-1) is detected in proliferating cells from nonhominoid primate species. A single class of TPI mRNA, which is increased 〉 10 fold following stimulation of quiescent cells, is detected on northern blot analysis and S1 nuclease digestion analysis of RNA from quiescent and proliferating human cells. It is similar in size to the TPI mRNA from proliferating cells of the African green monkey, a primate species not expressing TPI-2. Comparison of the structure of the TPI gene from rhesus monkey (nonexpressing species) to the gene from expressing species does not suggest a mechanism for generating TPI-2. Thus, the regulation of the expression of the hominoid restricted, proliferation specific subunit of TPI has been further defined, although the mechanism for generating TPI-2 remains elusive.
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 24 (1989), S. 67-80 
    ISSN: 0148-7280
    Keywords: mouse ; human ; abnormal hatching ; twinning ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Hatching in vitro was studied following zona drilling of 507 two-cell mouse embryos using three methods: 1) acidic Tyrode's (AT), 2) partial zona dissection (PZD) using a sharp micronecdle, and 3) zona chiseling (CH), using a large beveled needle. PZD and CH were performed while the embryos were kept in a sucrose/PBS solution. Hatching was compared to 191 umnicromanipulated controls. The incidences of cavitation and completion of hatching did not differ between groups, however more micromanipulated embryos (20-25%) hatched partially than controls (9%). The zona pellucida thinned in 59/59 (100%) control blastocysts during expansion, but in only 3/205 (2%) micromanipulated blastocysts. The hatching gap was wide in all control embryos, but smaller in 96/129 (75%) micromanipulated embryos. Partially hatched blastocysts with a ‘figure-8’ shape were found in 59/129 (46%) micromanipulated embryos and in none of the 39 hatching controls. Hatching usually occurred a day earlier in micromanipulated embryos as 214/218 (98%) had started extruding on day 5 as compared to 20/59 (27%) control blastocysts. Fifty percent of 1-day-old human oocytes were fertilized following PZD and reinsemination and 15/31 (48%) were monospermic. Thirteen monospermic embryos cleaved, six compacted and four cavitatcd - of these, three extruded through the PZD incision upon expansion. The zonae did not thin and one blastocyst twinned spontaneously as it was caught between the thick ridges of the PZD hole. Results indicate that the hatching process is abnormal following zona drilling; more embryos start hatching, extrusion occurs earlier, and many become trapped which may lead to artificial twinning or the formation of trophoblastic vesicles.
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  • 7
    ISSN: 0263-6484
    Keywords: Polyclonal antiserum ; receptor ; human ; uterus ; breast ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Polyclonal antiserum was generated in guinea pigs immunized with the 116 000 Mr rabbit uterine progesterone receptor (PR). The PR antigen was partially purified by DEAE-cellulose chromatography and preparative sodium dodecyl sulphate-polyacrylamide gel electrophoresis, transferred to nitrocellulose, and the 116 000 Mr band excised and injected into guinea pigs. The antiserum recognized on protein blots rabbit uterine PR of Mr 116 000 and 81 000. The antiserum was judged to be specific for PR from normal and malignant human tissues as determined by sedimentation shift on sucrose gradients, immunoprecipitation studies, protein blotting, and fluorographic analysis using photolabelled samples. Comparison of protein blots probed with this polyclonal antiserum or with a recently obtained monoclonal antibody to human PR indicated that similar PR structures were recognized in rabbit and human samples by both antisera. Characterization of the polyclonal antiserum has demonstrated its suitability for investigating the immunolocalization or PR in normal and malignant human tissues as well as the receptor structure detected on protein blots.
    Additional Material: 3 Ill.
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  • 8
    ISSN: 0197-8462
    Keywords: human ; calorimetry ; dielectric heaters ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: The heat uptake that resulted from immersing the hand and wrist into a water-filled calorimeter maintained at temperatures between 37-40 °C was measured under standard conditions in a group of eight subjects of either sex. The rate of heat transfer (W) increased exponentially with temperature and was a function of hand or body size and age, but not sex. The heat transfer rate normalized to hand mass (W.kg-1) was determined by temperature and age: best-fit mean values (and 95% confidence limits of the population) were 6.0 W.kg-1 (3.2-11.2 W.kg-1) at an immersion temperature of 37 °C and 25.4 W.kg-1 (13.7-47.0 W.kg-1) at 40 °C. The application of these results to limits on specific energy absorption rate induced in the hands and wrists by radiofrequency dielectric heat sealer welders is discussed.
    Additional Material: 1 Ill.
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  • 9
    ISSN: 1573-2568
    Keywords: vasoactive intestinal peptide ; substance P ; autoradiography ; small intestine ; colon ; binding ; smooth muscle ; lymphoid tissue ; mucosa ; human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Vasoactive intestinal polypeptide (VIP) and substance P are found in neurons in the lamina propria and submucosa and muscularis propria of human small intestine and colon. VIP receptors coupled to adenylate cyclase are present on epithelial, smooth muscle, and mononuclear cells. This study analyzes the distribution of[125I]VIP binding and [125]substance P in human colon and small intestine using autoradiographic techniques. [125I]VIP binding was present in high density in the mucosal layer of colon and small intestine. [125I]VIP binding was not significantly greater than nonspecific binding in smooth muscle layers or the lymphoid follicles. In contrast, [125I]substance P binding was present in high density over the colonic muscle but was not present over the mucosal layer. In human colon cancer, [125I]VIP grain density over the malignant tissue was only slightly higher than background. These autoradiographic studies of [125I]VIP binding indicate that the highest density of VIP receptors was found in the small intestine and superficial colonic mucosa, whereas the density of substance P receptors was highest over the smooth muscle layers. These findings suggest a mismatch between immunochemical content of the peptide and autoradiographic density of the receptor.
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  • 10
    ISSN: 1573-2568
    Keywords: human ; stomach ; duodenum ; mucosa ; prostaglandin synthesis ; antacids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Using14C-labeled arachidonic acid as precursor for in vitro prostaglandin synthesis, the effect of an antacid containing Al (OH)3, Mg(OH)2 and CaCO3 on endogenous prostaglandin synthesis was investigated in antral and duodenal mucosa of healthy volunteers. After three weeks of treatment with a high-dose antacid, there was no detectable change in the total capacity of the mucosa for prostaglandin synthesis, but the prostaglandin profile was markedly altered. The relative amounts of PGE2 and PGF2α synthesized by antral and duodenal mucosa increased at the expense of the prostaglandinsA2/B2, thromboxane A2, and prostacyclin. In a short-term study, this change was not observed following a single antacid dose within 1 hr after application. It is concluded that long-term antacid treatment may alter the prostaglandin pattern formed by gastroduodenal mucosa and this may be related to its therapeutic effect.
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  • 11
    ISSN: 1573-2622
    Keywords: electroretinogram ; human ; oscillatory potentials ; photopic ; retinopathy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Of all the electroretinogram (ERG) components (a-wave, b-wave, and oscillatory potentials) only one oscillatory potential, OP2, was found to be significantly correlated with the absolute intensity of the flash stimulus (i.e., the intensity of the stimulus irrespective of the state of retinal adaptation). Our finding was further confirmed in single cell recordings of lateral geniculate unit activity in rabbits in which peak time of OP2 was found to correlate better with the geniculate activity. For these reasons we have identified OP2 as the “intensity coding” oscillatory potential of the ERG. In order to investigate if this new feature could have some clinical significance, we examined photopic ERGs recorded from patients affected with various retinopathies. In most instances the peak time of OP2 paralleled that of the b-wave, that is, in the ERG with delayed b-wave the peak time of OP2 was also delayed, while in ERGs with normal b-wave peak time the peak time of OP2 was also normal. However, in some conditions (especially in cone-rod diseases) a delayed OP2 was found in ERGs with normal b-wave peak times.
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  • 12
    ISSN: 1573-2568
    Keywords: human ; duodenum ; bicarbonate ; indomethacin ; prostaglandin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In humans, prostaglandins of the E1 class stimulate duodenal mucosal bicarbonate secretion, whereas the cyclooxygenase inhibitor, indomethacin, decreases both mucosal PGE2 and bicarbonate production. The purpose of this study was to determine whether a synthetic prostaglandin E1, enisoprost, diminished the inhibitory effects of indomethacin on mucosal bicarbonate secretion. In seven healthy subjects the proximal 4 cm of duodenum was isolated by occluding balloons. The isolated test segment was perfused with 154 mM NaCl (2 ml/min, 37° C). Each subject participated in four separate tests in random order. Indomethacin, 50 mg, or placebo was given 13 and 1 hr before testing. After measuring basal bicarbonate secretion, either 100 μg of prostaglandin E1 or placebo (in 154 mM NaCl) was perfused into the test segment over 30 min. As anticipated, PGE1 significantly increased duodenal mucosal bicarbonate secretion, and indomethacin decreased resting bicarbonate secretion. Indomethacin pretreatment significantly enhanced (P〈0.03 the mucosa's response to PGE1 compared to PGE1 alone. These results further support the observations that endogenous prostaglandins, in part, regulate human proximal duodenal bicarbonate secretion. Furthermore, suppression of endogenous prostaglandin generation results in an increased sensitivity of the duodenal mucosa to PGE1.
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  • 13
    ISSN: 1573-2568
    Keywords: stomach ; duodenum ; bicarbonate secretion ; enprostil ; human ; amphibian ; prostaglandins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The protective and ulcer healing properties of prostaglandins are well established. We have explored the possible mode of action of enprostil, a synthetic dehydroprostaglandin E2, on amphibian gastroduodenal mucosal bicarbonate secretion in vitro and on human gastric bicarbonate secretion in vivo. Addition of enprostil (10−6 M) to the luminal solution of isolated amphibian gastric mucosa produced a 28% increase in bicarbonate secretion without a change in transmucosal potential difference. The same concentration of enprostil added to the luminal solution of isolated amphibian duodenal mucosa produced a 37% increase in bicarbonate secretion and was associated with a rise in transmucosal potential difference. The gastric output of bicarbonate from the human stomach has been calculated using a perfusion technique before, during, and after perfusion with enprostil (35 μg) in six healthy volunteers. A significant 78% increase in bicarbonate secretion occurred during the period of enprostil perfusion, falling to normal during the postenprostil period. These changes were caused mainly by an increase in gastric secretory volume with insignificant increases in bicarbonate concentration. These results suggest that stimulation of gastroduodenal bicarbonate secretion by enprostil may play a role in its protective actions.
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  • 14
    ISSN: 1573-2568
    Keywords: human ; rectosigmoid ; electrical stimulation ; cerebral evoked potentials
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We used electroencephalographic methods to evoke and record cerebral responses to electrical stimulation of the rectosigmoid colon in eight healthy male volunteers, 20–40 years old. The stimulus was applied via a probe equipped with bipolar ring electrodes which were attached by suction to the mucosa. The probe was positioned 20 cm above the anus. Cerebral responses were recorded by EEG electrodes. Evoked potentials (EPs) in response to electrical stimulation consisted of a series of successive peaks and troughs in the EEG with good reproducibility within and between subjects. The shape and latencies of the intestinal EPs were comparable to other types of EPs reported before. It is concluded that reproducible EPs can be recorded from the scalp after electrical stimulation of the rectosigmoid. The similarity in appearance of these EPs to those previously reported suggests that visceral afferents were stimulated. The technique may become a useful tool to study visceral nervous connections to the brain in health and disease.
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  • 15
    ISSN: 1573-2568
    Keywords: human ; colonic slow-wave activity ; myoelectric activity ; fast Fourier transform
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The fast Fourier transform (FFT) has been used to determine frequency components of colonic slow-wave activity. We studied the effect of (1) recorder filter characteristics, (2) number of data points and, (3) data window overlap technique and ingestion of a 1000-kcal meal on the resulting power spectrum. Human rectosigmoid slow-wave activity was recorded in nine normal subjects and stored on FM tape for computer analysis. The dynograph filter characteristics were tested using square wave signals, and derived compensation factors were applied to the FFT before viewing. The dynograph filter, when set to optimize visualization of slow waves, attenuates low frequencies nonlinearly. Failure to compensate for the dynograph filter results in inaccurate detection of slow-wave frequencies. FFT of 1-min data gives a different power spectrum than an FFT of 4 min data, indicating a rapidly changing waveform. FFT's of 1 min of data when examined over time fail to demonstrate a consistent frequency spectrum, confirming this conclusion. The lower frequencies in the normal human rectosigmoid are present at the greatest power. These studies indicate that the colon has slow waves of irregular frequencies, in contrast to the stomach or small intestine. No change in the dominant frequency was seen following the ingestion of a 1000-kcal meal.
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  • 16
    ISSN: 1573-2622
    Keywords: electroretinogram ; oscillatory potential ; diphenylhydantoin ; rabbit ; human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Acute administration of diphenylhydantoin (DPH) in rabbits produces a significant increase in the amplitude of the a-wave. A marked increase in the amplitude of the b-wave is also noted but the time course is slower than that for the a-wave. While in controls the oscillatory potential (OP) recordings essentially consist of three major types, recordings taken after DPH injection consist of one major OP (OP2), which appears to be a result of the fusion of the original OP2 with another OP produced by the DPH injection. A similar blend of OPs was also seen in ERGs recorded from three human subjects on DPH therapy.
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  • 17
    ISSN: 1572-9699
    Keywords: animal ; animal products ; antimicrobial resistance ; environment ; human ; Salmonella
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A total of 748 Salmonella strains (97 serovars) isolated from human (291), animal (119), environmental (141), food (102) and animal feed (95) sources were examined for resistance to 9 antimicrobial agents. Most of the human isolates were from hospitalized patients (282). An overall resistance rate of 98.8% was determined with 100% for human and environmental isolates. Resistance to sulfadiazine (87.7%) was most common, followed by streptomycin (61.2%), ampicillin (39%) and trimethoprim-sulphamethoxazole (37.9%). Fifty one different resistance patterns were identified with Su (164 strains), Su-Sm (122) and Su-Sm-Tc-Cm-Km-Ap-Nx-Gm-Tm (95) predominating, the latter occurring only in human isolates. Multiple resistance was most frequently found among human isolates, particularly in S. derby and S. typhimurium strains. The relationship between antibiotic resistance, serovar and source of isolation of the Salmonella strains is discussed.
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  • 18
    ISSN: 1435-1803
    Keywords: anatomy ; human ; monoclonalantibody ; myosin ; ventricle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary All fibers in three normal, four dilated, and two ischemic human ventricles were classified according to their myosin content using three sets of monoclonal antibodies each specific for one myosin heavy chain isoform (α, β and β′). Numerous fibers contained only β myosin heavy chain (denoted as β fibers), others contained either α and β, or β and β′ myosin heavy chain (denoted as αβand ββ′ fibers, respectively). The percentages of αβ fibers were systematically determined along the walls of seven homologous regions of the ventricular myocardium. In all ventricles, there was an αβ-fiber transmural gradient, with less αβ fiber in the subendocardium than in the subepicardium. More αβ fibers were found in the right than in the left ventricular wall but there was no difference between the mid-portion and the apex of the free wall of each ventricle. The diseased ventricles contained a lower αβ fiber percentage than the normal hearts. ββ′ fibers were very rare in the normal ventricles (less than 5%) and almost inexistent in pathological hearts. The correlation between the mean αβ fiber percentages of the diseased hearts and their cardiac indices (r=0.88, P〈0.05) suggests that the small amount of α myosin distributed in a large number of ventricular fibers could play a role in the contractile performance of the heart. In conclusion, this study provides evidence for 1) an αβ fiber transmural gradient, and 2) a lower α myosin ratio in discased than in normal human ventricle.
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  • 19
    ISSN: 0899-0042
    Keywords: pharmacokinetics ; terbutaline ; enantiomers ; human ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Terbutaline is a β2-agonist and administered as the racemic mixture. The pharmacokinetics of the separate enantiomers differ with respect to degree of absorption and clearance. In the present study, repeated doses of racemic terbutaline were given to six healthy volunteers. Plasma was analyzed for the concentrations of the two enantiomers. The observed plasma concentrations at steady state differed from those predicted from the values observed after single dose administration of the separate enantiomers. The difference between the observed and predicted values can be tentatively explained by a combined influence of (-)-terbutaline on the absorption of (+)-terbutaline and the influence of (+)-terbutaline on the elimination of (-)-terbutaline. The results have implications for the interpretation of effect/concentration studies with terbutaline, but do not affect the doses used in clinical practice.
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  • 20
    ISSN: 0148-7280
    Keywords: sperm ; human ; sperm motility ; kinematics ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Tracks of 30 progressively motile washed human spermatozoa were plotted manually from 200-Hz frame rate video recordings. Tracks at 100, 66.7, 50, 40, 33.3., 25, 20, 10, and 5 Hz were then constructed using every 2nd, 3rd, 4th, 5th, 6th, 8th, 10th, 20th, or 40th point. The 200-Hz tracks were analyzed by traditional manual methods, and all ten sets of tracks analyzed using a computer-assisted method (“Videomot,” developed originally to analyze 30-Hz tracks) to eliminate observer bias. Progression velocity (VSL) remained constant under all analysis conditions. Average path velocity (VAP) also remained essentially constant, although Videomot was less reliable at high frame rates due to problems in determining the average path. Curvilinear velocity (VCL) was very frame rate dependent (the 25-Hz mean value was only 56.5% of that at 200 Hz), and Videomot was more accurate than manual analysis at 200 Hz. Values of the amplitude of lateral head displacement (ALH) were acceptable at most frame rates. At 〈 66.7 Hz the inclusion of spurious curvilinear track deviations caused lower mean ALH values, and at 5 Hz ALH could not be measured since the track was essentially the average path. Beat/cross frequency (BCF) was also frame rate dependent; at high rates there was the same problem as with ALH measurements, while at ≤ 25 Hz the maximum BCF was restricted by the frame rate. We conclude that human sperm movement characteristics can be measured at frame rates ca. 30 Hz but only if the constraints affecting VCL and BCF values are understood and accepted. Finally, 〈 10 Hz can only give values for VSL and, perhaps, VAP.
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  • 21
    ISSN: 0148-7280
    Keywords: human ; spermatozoa ; egg extract ; Xenopus laevis ; pronucleus ; chromosome ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The conditions necessary for inducing pronucleus formation and chromosome condensation of human sperm nuclei were studied using Xenopus egg extracts. When lysolecithin (LC)-and dithiothreitol (DTT)-treated spermatozoa were incubated with egg extract prepared with an extraction medium containing 10 mM EGTA, sperm nuclei transformed into chromosomes, bypassing the pronuclear stage. On the contrary, LC-DTT-treated spermatozoa incubated in egg extract without EGTA mimicked LC-permeabilized Xenopus spermatozoa in that they underwent pronucleus formation accompanied by DNA synthesis and subsequent chromosome condensation in the correct chronological order. These observations suggest the importance of intracellular calcium for regulating the states of nuclear chromatin. LC-permeabilized human spermatozoa were not responsive to the egg extract without any additives, but formed pronuclei when incubated with the egg extract supplemented with 5-10 mM DTT. However, subsequent chromosome condensation of sperm nucleus did not occur in the DTT extract. This suggests that disulfide-reducing agent blocks transformation of sperm pronuclei into condensed chromosomes.
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  • 22
    ISSN: 0148-7280
    Keywords: acrosome reaction ; sperm ; human ; fine structure ; follicular fluid ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: It has been suggested that the morphology of the human sperm acrosome reaction (AR) is markedly different from that of other mammalian sperm. The present study examines the fine structural events of the early stages of the human sperm AR as initiated by preovulatory human follicular fluid. Human sperm, capacitated in vitro for 6 hr at 40°C (90% motility) were diluted with equal volumes of follicular fluid before fixing in cacodylate-buffered glutaraldehyde at 5, 10, 15, 20, and 180 sec. Fixed sperm were treated with either tannic acid or thiocarbohydrazine and OsO4. Over 2,000 sperm were viewed. By 5 sec, 2% of the sperm had initiated the AR. By 15 sec, 8% of the sperm were in some stage of the reaction, and after 180 sec 40% of the sperm had completed the acrosome reaction. The initial stages of the human AR are characterized by a swelling or decondensation of the acrosomal matrix. The fusion between the plasma membrane and outer acrosomal membrane begins at the most anterior tip of the head and progresses toward the equatorial segment. Fusion and fenestration ended at the equatorial segment. With thiocarbohydrazine + OsO4 fixation the fused membranes are distinct hybrid vesicles with the outer acrosomal membrane being far more electron dense. The acrosomal matrix is retained by 20 sec, but by 180 sec the matrix is completely dispersed, even when viewed after tannic acid fixation. Also by 180 sec, vesicles were being progressively lost. It is therefore concluded that the morphology of the human sperm AR, as initiated by human follicular fluid, is not unique, but is similar to that described for other mammalian sperm.
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  • 23
    ISSN: 0148-7280
    Keywords: human ; spermatozoa ; cryopreservation ; freezing-thawing ; chromatin ; acridine orange ; Feulgen-DNA ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Cryopreservation and freezing-thawing effects on the fertilizing ability of human spermatozoa commonly are evaluated by post-thaw motility. Various studies have depicted the ultrastructural changes caused by freezing-thawing, yet the chromatin alterations have been studied very limitedly. Our aim was to determine the extent to which freezing-thawing alters the chromatin of human spermatozoa, using two analytical methods: acridine orange staining and Feulgen-DNA cytophotometric studies. Both methods revealed a dramatic effect of freezing-thawing on sperm chromatin: the native DNA content decreased as did the Feulgen-DNA content, and sperm surface area was reduced. These results indicate an effect on DNA, diminished accessibility for Feulgen, and a decrease in nuclear surface area and prompt us to hypothesize a relationship between an “overcondensation” state for sperm chromatin after freezing-thawing and a lower conception rate for human semen after cryostorage.
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  • 24
    ISSN: 1573-2568
    Keywords: pyruvate ; lactate ; human ; duodenal juice
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Pyruvate and lactate in duodenal aspirates were investigated to determine whether they are excreted from human pancreas as substrates for alkaline secretion as is bicarbonate. Secretion of these acids was compared with that of another organic acid, citrate, which is thought to be excreted in close relationship to digestive enzymes. All acids were assayed in the fluid obtained from 11 subjects without pancreatic diseases, before and after sequential intravenous injections of 1 unit/kg pancreozymin and 1 unit/kg secretin. Pyruvate concentrations were markedly increased by each stimulation, especially by secretin, and the cumulative excretions of pyruvate and bicarbonate after secretin stimulation were significantly correlated among the subjects. In contrast, lactate concentrations, although high just after administration of pancreozymin, declined to a considerable extent following each injection, rather similar to those of protein or citrate. These data suggest that pyruvate may be secreted from human pancreatic duct cells similar to bicarbonate secretion through mechanisms related to alkaline secretion.
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  • 25
    ISSN: 1573-2568
    Keywords: gastric emptying ; posture ; radionuclides ; human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The purpose of this investigation was to compare the effect of body posture on gastric emptying measurements of radiolabeled meals. Eight healthy male subjects were studied on four separate days. During each study subjects were fed a standardized meal of beef stew labeled with technetium-99m sulfur colloid, and orange juice. Measurements of solid-phase gastric emptying rates were obtained by a gamma camera. Subjects were studied in the lying, sitting, standing, or combined sitting-standing postures. The results demonstrated that the lying position significantly slowed gastric emptying compared to all other positions. Conversely, a decrease in emptying times of 51% and 35% occurred in the combined sitting-standing position compared to the lying and sitting position. These results support a marked effect of body posture on the radionuclide measurement of gastric emptying.
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  • 26
    ISSN: 1573-2630
    Keywords: drug delivery ; human ; intravitreal injection ; liposomes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Intravitreal liposome-encapsulated antibiotics and antiviral drugs were used in patients with acute toxoplasmosis retinochoroiditis, presumed propionibacterium acne endophthalmitis after cataract surgery, and presumed cytomegalovirus retinitis associated with AIDS. A single intravitreal dose was effective in the treatment of all the conditions. Intravitreal liposomes may prove to be an advantageous drug delivery system for the treatment of chronic intraocular inflammatory disorders.
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  • 27
    ISSN: 1435-1463
    Keywords: Melatonin ; Seasonal Affective Disorder ; human ; phototherapy ; winter depression ; circadian rhythm ; phase response
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary It is well-established that human nocturnal melatonin secretion is suppressed by presentation of artificial light 〉2,000 lux, a level that is also therapeutically effective in alleviating winter depression symptoms of Seasonal Affective Disorder [SAD]. Furthermore, early-morning bright light induces phase advances of the melatonin cycle in SAD patients (Lewy et al., 1987 a). The functional significance of melatonin in SAD remains unclear. With plasma melatonin sampled at 20-min intervals in a series of overnight studies, we found marked phase delays of the cycle, relative to that previously reported for normals, in 4/5 depressed SAD patients. 2,500 lux light exposure at 6–8a.m. resulted in exponentially declining melatonin levels that approached low daytime baselines within two hours (t1/2 = 45.52 min). All five patients showed clinical remissions as well as phase advances of the melatonin cycle of 0.75 to 3.27 hours (mean, 1.94± 0.84hours) after one week of daily exposure from 6–8a.m. and p.m. These results suggest that the combination of early morning and early evening light exposures induces circadian phase adjustments similar to those of morning light alone, by impacting a photosensitive interval when, in SAD, melatonin secretion overshoots its normal nocturnal phase.
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  • 28
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Clinical Anatomy 1 (1988), S. 285-294 
    ISSN: 0897-3806
    Keywords: gross anatomy ; pharynx ; human ; Life and Medical Sciences ; Miscellaneous Medical
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The pharyngeal raphe is described traditionally as a straight, continuous, median, fibrous band that provides attachment for and separates each pair of the three constrictor muscles of the pharynx. The posterior wall of the pharynx was dissected in 236 adult human cadavers of the Mongoloid, Caucasoid, and Negroid races. The arrangement of the raphe in each specimen was recorded. The various arrangements of the raphe were then organized into three types (I, II, or III) and eight subtypes (a, b, or c). The raphe was most often (47%) located between the inferior constrictor muscles only (type I) where it was either a straight or a curved line or had a fusiform to oval shape. The second most frequent pattern (40%) was a raphe located between the superior and middle constrictor muscles only (type II) with a shape similar to type I. The middle constrictor muscles were sometimes well developed and attached superiorly to the pharyngeal tubercle by way of a strong raphe. The raphe extended from the pharyngeal tubercle through all the constrictor muscles to the esophagus (type III) in only 13% of the specimens and was more often interrupted rather than a continuous line. The type usually described in anatomy textbooks (type IIIa) was found in only 5% of the specimens.
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  • 29
    ISSN: 1420-9071
    Keywords: Temperature regulation ; pathology ; human ; nosography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
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  • 30
    Electronic Resource
    Electronic Resource
    Springer
    ISSN: 1420-9071
    Keywords: Circadian rhythms ; light-dark cycles ; human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
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  • 31
    ISSN: 1573-0832
    Keywords: Aspergillus stromatoides ; case report ; infection ; sino-orbital ; human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract We report a case of human infection due to Aspergillus stromatoides. To our knowledge this organism has not previously been described as causing human infections. The infection of sino-orbital tissues was of 3 1/2 years duration and the patient died following cerebral involvement despite seven months of hospitalisation and therapy including amphotericin B, 5-fluorocytosine and rifampicin.
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  • 32
    ISSN: 1573-5052
    Keywords: Classification ; Disturbance ; human ; Disturbance: natural ; Ordination ; Serengeti National Park ; Tanzania ; Tropical grassland ; Tropical savanna
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Patterns of revegetation on natural and human-caused disturbances in grasslands and savannas of the Serengeti National Park, Tanzania, were investigated by recording species compositions on all disturbances, in the undisturbed vegetation, and in unique microhabitats in 51 sites along a north-to-south transect through the park. The 487 resulting samples were ordinated by detrended correspondence analysis (DCA) and classified by two-way indicator species analysis (TWINSPAN). Natural disturbances were, in most cases, ordinated near or classified together with the climax sample from the same site but human-caused disturbances were classified separately. Human disturbances from all regions of the park were classified together in one group, while natural disturbances were divided into communities associated with different rainfall regimes. Natural disturbances were revegetated by species growing in the surrounding undisturbed communities while human-caused disturbances were revegetated by a set of ruderal species not found in the undisturbed communities nor in natural disturbances.
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  • 33
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 18 (1987), S. 97-107 
    ISSN: 0148-7280
    Keywords: protein synthesis ; oocyte ; human ; electrophoresis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: As a first step toward understanding control of gene expression in early human development, an analysis of protein synthesis and amino-acid transport in unfertilized mature oocytes was initiated. Qualitative patterns of protein synthesis were examined in individual oocytes cultured in medium containing radiolabeled methionine. No differences in synthetic pattern of proteins, resolved by one-dimensional electrophoresis and fluorography, were observed in oocytes analyzed from times varying from 12 to 52 hr following collection by laparoscopy. Contamination by follicular or corona radiata cells was readily distinguished on the basis of increased relative synthesis of a polypeptide with Mr = 44,000, a dominant product of synthesis in follicular cells. Based on the specific activity of the methionine precursor, the absolute rate of synthesis was measured to be about 50 pg/oocytc/hr, a value higher than in mouse unfertilized eggs. No difference in protein synthetic rate was observed in oocytes analyzed at 12 hr postcollection versus later times up to 50 hr postcollection. Competition of methionine uptake by leucine, efflux of radiolabeled methionine from preloaded oocytes into medium containing methionine and uptake of methionine in medium with low sodium ion concentration was observed. These findings are consistent with the presence of an L (leucine-preferring) system for neutral amino acid transport, similar to that in mouse and rabbit eggs. Total protein was measured to be about 150 ng/oocyte, a value five times that of the mouse. These studies provide basic data for further analysis of oocytes and perhaps preimplantation stage embryos in the future.
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  • 34
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 8 (1987), S. 281-293 
    ISSN: 0192-253X
    Keywords: mouse ; human ; cow ; maps ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Technological advances in the 1970s encouraged the mapping of homologous gene loci in different mammalian species, including mouse and man. One hundred eighty-five homologous loci have now been mapped in these two species. Conservation of linkage is sufficient to identify substantial segments of the two genomes that have been left intact since their divergence from a common ancestor. The recognition of these conserved segments allows experimental manipulation of mouse chromosomes or chromosomal regions to produce models of human chromosomal anomalies of medical importance.Comparative gene mapping has been extended beyond mouse and man and the genomes of some species, including domestic cattle, appear to be more highly conserved relative to humans than the mouse. Such species may be particularly useful in providing models of human chromosomal anomalies that cannot be duplicated in laboratory mice.
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  • 35
    ISSN: 1573-6822
    Keywords: cell injury ; epithelium ; human ; organ culture ; regeneration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Human esophageal, tracheal, and pancreatic ductal fragments were collected at autopsy after a postmortem interval of 12 hours or less and maintained in explant organ culture for 30 days. The viability and growth of the explants was assessed by morphology, LDH enzyme release, and cellular outgrowth. The viability and growth of the bronchial explant epithelium was directly related to the postmortem interval. Esophageal epithelial regeneration followed the desquamation of the superficial cell layers. Pancreatic epithelia appeared to grow more slowly and with less outgrowth than the other tissues. Epithelial cell growth along the explant surface and onto the culture dish appeared to proceed through the well-characterized process that follows cell injury, i.e., flattening, migration, replication, and differentiation. Thus, sufficient numbers of viable epithelial cells capable of regeneration were present in routine autopsy epithelium, but there was considerable variation from tissue to tissue and case to case. The most effective and accurate approach to follow when evaluating and predicting the growth and viability of these explants is by using a combination of morphologic, enzymatic and biologic assays. Errors in the interpretation of viability are possible when only one assay method is utilized. These tissues grown in explant organ culture are suitable for studies on the mechanism and response of epithelia to cell injury, recovery and wound healing.
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  • 36
    ISSN: 1573-2592
    Keywords: IgA ; human ; bone marrow ; B cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Although human bone marrow has been implicated in the production of serum immunoglobulins, little information is available concerning the kinetics of antibody production (primary- or secondary-type humoral response) or the cells that are responsible for antibody production in human bone marrow. In this study, the kinetics of and cells responsible for antibody production in the bone marrow were investigated. Previous studies have demonstrated that human bone marrow mononuclear cells secrete a significant amount of IgAin vitro. This finding led to the focus of the present investigation on bone marrow IgA production. The results reported here demonstrate that IgA was synthesized de novo in cultures of bone marrow mononuclear cells; its peak concentration in the culture supernatants preceded that of IgM; its production was totally inhibited by the addition of microgram quantities of anti-α-chain antiserum, while milligram quantities of anti-μ-chain antiserum were required for even partial inhibition of IgA production; and the culture of isolated IgA-bearing cells resulted in a greater than 13-fold increase in IgA concentration in the culture supernatants as compared with those from unseparated bone marrow mononuclear cells. From this study, it was concluded that bone marrow produces IgA as a secondary or anamnestic response to some undetermined stimulus and that IgA-committed B cells residing in, although probably not stimulated in, the bone marrow compartment were responsible for the IgA synthesis and secretionin vitro.
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  • 37
    ISSN: 1573-2622
    Keywords: electroretinogram ; human ; oscillatory potentials ; retinal ; retinal disease
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This paper reviews current knowledge concerning the oscillatory potentials (OPs) of the electroretinogram (ERG). The first section describes the basic characteristics of the OPs primarily studied in healthy subjects. The behavior of the OPs is different from the a- and b-waves, indicating separate mechanisms for generation of the OPs compared with the major components of the ERG. The second section deals with the present view of the origin of the OPs collected from experimental studies of the vertebrate retina, including the primate. Findings favor the conclusion that the bipolar (or interplexiform) cells are the probable generators of the OPs. The third section gives clinical examples of the sensitivity of OPs to early disturbances of retinal function in different eye diseases.
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  • 38
    ISSN: 1573-2622
    Keywords: foveal ; generators ; human ; topography ; visual evoked potential
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Scalp potentials elicited by pattern reversal, pattern onset, and flash stimulation have been studied in normal subjects by means of a 16-channel brain mapping system. In two groups of experiments the topography of the major positive component in each response was compared with 4° full- and lateral half-field stimuli and, for more detailed exploration of the pattern components by M-scaled stimuli selected to activate 1 cm2-patches of striate cortex and associated extrastriate re-projections. The 4° stimuli were found to elicit scalp distributions for the pattern reversal P100 and the pattern onset C1 consistent with striate and extrastriate visual cortical origins respectively. Data on the flash P2 component suggest that stimulation was not localized accurately; this may have been due to lateral spread of neural activity in the retina. Predictably, the M-scaled stimuli showed extensive inter- and intra-individual variations depending on stimulus type and location relative to fixation. The manner in which, in some subjects, the region of maximal activity on the map appears to migrate with change of stimulus position possibly reflects local retinotopic order in visual evoked potential generator areas. However, data are neither extensive nor detailed enough to be conclusive.
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  • 39
    ISSN: 1573-2622
    Keywords: focal electroretinogram ; human ; intensity ; macula ; optic atrophy ; retrobulbar neuritis ; pattern electroretinogram
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We studied nine cases of retrobulbar neuritis with confirmed multiple sclerosis and six cases of optic atrophy from other causes. Pattern and focal electroretinograms (macular ERGs) were recorded with high (400 cd/m2) and low (40 cd/m2) intensity stimuli. Contrast sensitivity was also measured with a simple printed test. Luminance was not markedly important. High spatial frequency contrast sensitivity was significantly correlated with pattern ERG amplitude. Pattern and focal ERG amplitude ratio was usually reduced, but the effect was not correlated with contrast sensitivity or large enough to be useful clinically. In optic atrophy the pattern ERG (PERG) was clearly more severely reduced than the focal ERG (FERG). In retrobulbar neuritis both ERGs were equally and more severely reduced even though the visual losses were less. In unilateral cases the PERG increased then decreased after the initial attack, as previously described (Arden et al., 1982). The results suggest that retinal layers beyond the ganglion cells may be affected in retrobulbar neuritis, but proximally generated, pattern-specific ERG components are selectively lost in optic atrophy.
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  • 40
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    Electronic Resource
    Springer
    Digestive diseases and sciences 32 (1987), S. 466-471 
    ISSN: 1573-2568
    Keywords: secretin ; enterogastrone ; human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We studied in humans the effect of exogenous secretin in a physiological dose on gastric acid secretion stimulated by pentagastrin and postprandial plasma gastrin concentration. Two doses of pentagastrin, 80 and 160 pmol/kg/hr were used to stimulate gastric acid secretion. Secretin in two doses, 2.8 and 5.6 pmol/kg/hr were tried to study the response on stimulated gastric acid secretion. Intravenous secretin in a dose of 5.6 pmol/kg/hr significantly inhibited the gastric acid output stimulated by intravenous pentagastrin in a dose of 160 pmol/kg/hr, from 11.25±1.5 to 5.99±1.34 meq/hr, while lower dose of intravenous secretin (2.8 pmol/kg/hr) failed to inhibit the gastric acid output stimulated by the same dose of pentagastrin. However, the lower dose of intravenous secretin (2.8 pmol/kg/hr) inhibited the gastric acid output significantly from 8.78±1.21 to 6.37±1.62 meq/hr when gastric secretion was stimulated by the lower dose of pentagastrin (80 pmol/kg/hr). The plasma concentrations of secretin during intravenous secretin in a dose of 2.8 pmol/kg/hr was similar to postprandial plasma concentrations of secretin as previously reported. Doubling the dose of intravenous secretin resulted in almost twofold higher plasma concentrations than postprandial plasma concentrations. In addition, the low dose of secretin (2.8 pmol/kg/hr) suppressed the integrated postprandial gastrin response from 13.9±3.7 to 11.2±2.8 ng/min/ml (P=0.05) when endogenous release of secretin was blocked by intravenous cimetidine. Since the dose of pentagastrin and secretin employed in this study fell in a physiologic range, the inhibitory effect of secretin on stimulated gastric acid secretion appears to be a physiologic action in humans. Contrary to the findings in dogs, the inhibitory action of secretin on gastrin release was not statistically significant but was highly suggestive.
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  • 41
    ISSN: 1420-9071
    Keywords: Pancreatic elastase II ; α2-macroglobulin ; aortic elastin ; human ; elastinolysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Human α2-macroglobulin-human pancreatic elastase II binding were investigated using a homologous substrate, human aortic elastin, in order to test the enzymatic activity. We demonstrated that two moles of α2-M are required to inhibit one mole of HPEII when the enzyme is added to a mixture of elastin and α2-M. In addition, when the elastase-α2-M complex is prepared under some circumstances, it exhibits an elastinolytic activity.
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  • 42
    ISSN: 1573-4927
    Keywords: triosephosphate isomerase ; variants ; human ; structural characteristics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Three new electrophoretic variants of human erythrocyte triosephosphate isomerase (TPI) have been partially purified and compared with the normal isozyme with respect to stability, kinetics, and immunological properties. TPI 2HR1, an anodally migrating variant, was less stable than normal in guanidine denaturation and thermodenaturation tests, although it exhibited normal kinetic properties. The level of enzyme activity in erythrocytes from the proband with the phenotype TPI 1-2HR1 was about 60% of the normal mean. The variant allozyme TPI 2NG1, an anodally migrating allozyme associated with normal activity, was very thermolabile at 55 and 57°C. It was also much more labile than normal in stability tests in buffers at pH 5 and pH 10, although it exhibited normal kinetic and immunological properties. TPI 4NG1, a cathodally migrating variant associated with normal activity and normal kinetic as well as immunological properties, was more stable than normal in pH 5 buffer. Family studies demonstrated that the unique characteristics of these variants are genetically transmitted. In two-dimensional electrophoresis of purified isozymes the variant subunits were separated from the normal in the pI axis. However, there is no difference between the variants and the normal in the molecular weight axis, suggesting that the variants result from single amino acid substitutions.
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  • 43
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    Electronic Resource
    Springer
    Human evolution 1 (1986), S. 221-231 
    ISSN: 1824-310X
    Keywords: Sexual dimorphism ; human ; innominate ; forensic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In the adult human innominate, pubis length and sciatic notch width are generally considered to offer the best prospect for reliable sex identification. Population variation in the extent of sexual dimorphism in these features was examined in two temporally distinct European skeletal collections of documented age and sex. (English and Dutch). A complex relationship was found to exist between pubis length and sciatic notch width with body size; these relationships differed both between the sexes and between the groups. Caution is therefore urged in the use of both metric and non-metric standards derived from one population and subsequently applied to other populations of differing origin.
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  • 44
    ISSN: 1573-6830
    Keywords: area postrema ; ultrastructure ; function ; human ; cat ; rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary 1. The area postrema is a circumventricular organ of the fourth ventricle of the mammalian brain. Although there are distinct gross anatomical differences in the appearance of this organ between “lower” mammals such as rodents and lagomorphs and “higher” mammals such as carnivores and primates, its fine structure is remarkably similar in all species studied. 2. There are many suggestions in the literature for a specific function for this area of the brain, ranging from its being a chemoreceptive trigger zone for the emetic response to its being a regulatory nucleus for the sleep cycle. The present report describes some comparative studies on the ultrastructure of this organ. 3. This information is discussed in relation to what is known about the neurochemistry of the area postrema and its connections with other brain regions and visceral structures. A suggestion is offered that our current knowledge of the area postrema is consistent with its performing many of its proposed functions in the context of a regulatory (“fine-tuning”) center for many autonomic functions.
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  • 45
    ISSN: 1573-6822
    Keywords: aldehyde dehydrogenase ; hepatocytes ; human ; rat ; carcinogens
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Aldehyde dehydrogenase was measured in primary cultures of hepatocytes obtained with a two-step collagenase perfusion either from human hepatic tissue or from livers of Fisher rats. Basal enzyme activity declines gradually as a function of time in culture, but remains at all times higher when measured with propionaldehyde and NAD (P/NAD) than with benzaldehyde and NADP (B/NADP). Treatment of the cultures with 2 μM of 3-methylcholanthrene for four days significantly increased the B-NADP activity of human and rat hepatocytes (tenfold and eightfold respectively). In human hepatocytes 3-methylcholanthrene increases also the P/NAD activity, but to a lesser extent (twofold), compared to the B/NADP activity. Due to the significant enhancement of B/NADP activity in cultures of human and rat hepatocytes after application of 3-methylcholanthrene, the initial difference in the basal activity levels between the P/NAD and B/NADP forms diminishes or, in the case of human hepatocytes, is even inverted. These results show for the first time that aldehyde dehydrogenase activity is increased in cultured human hepatocytes. This biochemical property is preserved in human and rat hepatocyte cultures, despite the rather quick loss of the basal aldehyde dehydrogenase activity.
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  • 46
    Electronic Resource
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    Springer
    Documenta ophthalmologica 63 (1986), S. 337-348 
    ISSN: 1573-2622
    Keywords: electroretinography ; human ; oscillatory potentials ; retina
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract During light adaptation a progressive increase in the intensity of a flash stimulus yields ERGs in which the a-wave shows a gradual reduction in peak time, while the b-wave appears to do the opposite. However, close inspection of the different ERG waveforms indicates that the wave identified as the b-wave for a threshold stimulus actually decreases in peak time with progressively stronger stimulus. Furthermore, what is identified as the b-wave for a threshold stimulus delivered in light adaptation will become a part of the a-wave complex if the same stimulus is used in dark adaptation. Data presented here indicate that the identification of the a- and b-waves of the ERG must be constantly revised according to the intensity of the stimulus and/or the level of retinal adaptation. These findings seriously challenge the validity of the a-b-wave nomenclature currently used in electroretinography. An alternative nomenclature, based on the first derivative (dv/dt) of the ERG wave, is proposed.
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  • 47
    ISSN: 1573-2622
    Keywords: contrast sensitivity ; focal electroretinogram ; human ; intensity ; maculopathy ; pattern electroretinogram
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Eighteen patients with early maculopathies of various etiologies were tested with pattern and focal electroretinograms (macular ERGs), with high (400 cd/M2) and moderate (40 cd/M2) stimulus intensities and a four-alternative forced choice (4AFC) contrast sensitivity test in addition to intensive clinical examinations. High spatial frequency contrast sensitivity loss on the 4AFC test was the most striking and consistent feature of all cases. The only eyes not outside normal contrast sensitivity limits were three in which diagnosis was uncertain and the patients had not recognized any problem, including two marginal solar burns. Maculopathy also substantially reduced macular ERG amplitides. Criterion scores on these tests separated patients from normals more effectively than other noninvasive procedures and only missed one eye detected by contrast sensitivity. Latencies were affected but the delays were of no clinical significance in the individual case. Stimulus intensity was not critical. The results indicate that contrast sensitivity testing and macular ERGs are very reliable indices of central visual dysfunction at a stage when visible macular changes are too subtle for confident diagnosis. Contrast sensitivity has appeal because of its reliability, objectivity, simplicity, and noninvasive nature. It is equally applicable to children and adults. Pattern and focal ERGs can establish that the visual deficit has a retinal origin and can provide the most reliable objective confirmation.
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  • 48
    ISSN: 1573-2622
    Keywords: vitreous body ; human ; rabbit ; cisterns ; canal of Cloquet ; bursa premacularis ; ink-injection ; stereo-lightmicroscopy ; SEM
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The naked human vitreous (sclera, iris and cornea removed) suspended in water does not reveal inner structures. After ink injection into the vitreous, the presence of different compartments and the existence of cisterns becomes evident. A concept of the internal system of cisterns is given on the basis of stereoscopic-lightmicroscopic images. An attempt is made to correlate images of the complete vitreous body, obtained with a stereo-lightmicroscope, with images of segments of cisternal walls produced with a scanning electron-microscope (SEM). A comparison is made between SEM-images of the vitreous bodies of human and rabbit eyes.
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  • 49
    ISSN: 1573-2622
    Keywords: scanning electron microscopy ; endothelial cell growth ; implant cytology ; intra-ocular lens ; human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In this study we have demonstrated the formation of an acellular and a cellular membrane on the surface of an explanted intra-ocular lens by scanning electron microscopy. The acellular membrane is considered to be the result of a physiological process, whereas the cellular membrane is looked upon as a pathological endothelial membrane formed as the result of intermittent touch between the implant and the endothelium.
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  • 50
    ISSN: 1435-1463
    Keywords: Tryptophan ; amino acid ; human ; carbohydrate ; protein ; serotonin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary It is well established that the ratio of the plasma tryptophan concentration to those of the other large neutral ammo acids determines the transport of tryptophan into the brain. Brain tryptophan levels, in turn, control production of the neurotransmitter serotonin. Protein-rich meals, when consumed in the morning after an overnight fast, have been shown to decrease the plasma tryptophan ratio, while carbohydrate-rich meals have the opposite effect. We now show that these meals have similar effects when consumed for lunch, even if they are preceded by a small breakfast meal.
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  • 51
    ISSN: 1573-8744
    Keywords: animal scaleup ; rat ; human ; weakly acidic drug ; weakly basic drug
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Various pharmacokinetic parameters—disposition half-life, t 1/2,z, metabolic clearance CLm, volume of distribution V, intrinsic clearance of unbound drug CLut, and unbound volume of distribution of tissues (distributive tissue volume / fraction of drug in tissue unbound, VT/fuT—are compared in rat and human for nine weakly acidic drugs, phenytoin, hexobarbital, pentobarbital, phenylbutazone, warfarin, tolbutamide, valproate, phenobarbital, and amobarbital, and six weakly basic drugs, quinidine, chlorpromazine, propranolol, pentazocin, antipyrine, and diazepam. With regard to all parameters, statistically significant correlations are obtained when parameters are plotted on a log-log plot. Correlation coefficients between the intrinsic parameters (CLuint or VT/fuT) were higher than those between the hybrid parameters (t1/2,z, CLm, or V). In general, these drugs were metabolized ten times more rapidly in rat than in human. With regard to the tissue distribution of these drugs, there was little difference between rat and human. Predictions of CLm, V, and t1/2, in humans using rat data were successful for most drugs, with a few marked exceptions.
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  • 52
    ISSN: 1573-7330
    Keywords: freezing ; in vitro fertilization (IVF) ; embryo survival ; human ; pregnancy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Studies on the cryopreservation of 162 four-cell and eight-cell human embryos indicate that morphological survival and pregnancies can be achieved by specific techniques of freezing and thawing. Survival rates are highest when embryos are cooled at 0.3°C/min to−80°C in the presence of 1.5 M dimethylsulfoxide (DMSO) and thawed at +8°C/min from −80 to +4°C. Morphological survival of four-cell and eight-cell human embryos after freezing and thawing is not affected by irregularites in blastomere size or the presence of small cytoplasmic fragments. Light and electron microscopic examination of fixed specimens indicates a good correlation between the appearance of frozen-thawed embryos at the dissecting microscope level and the extent of cryoinjury. Sixty-eight of 136 four-cell and eight-cell embryos (50%) survived with half or more of their blastomeres intact when cooled to low temperatures and thawed at the rates described. The transfer of these 68 embryos into 45 patients resulted in nine pregnancies.
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  • 53
    ISSN: 1573-4919
    Keywords: DNase I-sensitivity ; globin gene expression ; hematopoietic cell lines ; hemin ; human ; nuclear in vitro transcription
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Summary Northern blot analysis using probes specific for each of the human embryonic (ɛ), fetal (γ), and adult (β) globin genes indicates that the human lymphoblastoid F-265 cells express the embryonic and fetal globin genes. Unlike: the erythroid cell line K562, in which globin RNA levels increase during treatment with hemin in culture, globin RNA levels decrease in F-265 cells in the presence of hemin. This effect is reversible after passage of F-265 cells in fresh medium without hemin. Both the rates of globin RNA synthesis and the presence of DNase I-hypersensitive sites in hemin treated and untreated F-265 cells were investigated to identify the levels at which globin gene expression is controlled.
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  • 54
    ISSN: 0148-7280
    Keywords: human ; sperm ; zona pellucida ; zona-free hamster oocyte ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: In these experiments the mean number of sperm bound to the zonae pellucidae of immature human oocytes and to the vitelli of zona-free hamster oocytes were counted after centrifuging the oocytes through a discontinuous dextran gradient into a fixative. Sperm suspensions (107 sperm/ml) were preincubated in BWW medium containing 35 mg/ml of human serum albumin for 0 to 20 hr and coincubated with oocytes for 4 hr.The kinetics of sperm binding and sperm penetration were clearly different for the two types of oocytes in this system. Sperm binding to the zona pellucida appeared to be associated with zona penetration; when the zona was penetrated, many sperm were tightly bound and vice versa. A similar association between human sperm binding to the zonafree hamster oocyte and hamster oocyte penetration was not so apparent. Transmission electron microscopy revealed that all sperm which were “bound” to the hamster vitellus were acrosome reacted. On the surface of the human zona pellucida acrosome intact and acrosome reacted sperm were observed.These results suggest that tight binding of spermatozoa to the zona pellucida may be an important preliminary step in human fertilization. If this is true the activity of the sperm's “receptor for zona” may not be detected by the assay with zona-free hamster oocytes.
    Additional Material: 3 Ill.
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  • 55
    ISSN: 0148-7280
    Keywords: sperm ; human ; zona pellucida ; cervical mucus ; zona-free hamster oocyte ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The functional capacity for sperm interaction with the human zona pellucida and zona-free hamster oocyte was tested after human spermatozoa were capacitated by passage through a column of human cervical mucus. The results were compared with those obtained when spermatozoa from an aliquot of the same semen sample were capacitated by the standard laboratory methods involving sequential washing by dilution and centrifugation of the semen. Washed-capacitated sperm suspensions were more successful than mucus-capacitated sperm in attaching to the zona-free hamster oocyte and in fusing with its oolemma. However, the ability of mucus-capacitated sperm to penetrate the human zona pellucida was equal to washed capacitated sperm. These experiments demonstrate an approach that may be useful in comparative studies of human sperm capacitation in vivo and in vitro.
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  • 56
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 12 (1985), S. 85-89 
    ISSN: 0148-7280
    Keywords: spermatozoon ; cervical mucus ; human ; scanning electron microscope ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The ultrastructure of human cervical mucus was studied by scanning electron microscopy. In fertile women, naturally occurring midcycle cervical mucus showed an arrangement of parallel fibers oriented along the main axis of the mucus sample. Sperm migration through a column of cervical mucus in vitro was also studied. It was found that sperm present among the longitudinal fibers were oriented parallel to the them and to the main axis of the mucus sample.
    Additional Material: 2 Ill.
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  • 57
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 6 (1985), S. 33-40 
    ISSN: 0197-8462
    Keywords: human ; dosimetry ; safety ; radiofrequency ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Further studies of human whole-body radiofrequency (RF) absorption rates were carried out using a TEM-cell exposure system. Experiments were done at one frequency near the grounded resonance frequency ( ∼ 40 MHz), and at several below-resonance frequencies. Absorption rates are small for the K and H orientations of the body, even when grounded. For the body trunk in an E orientation, the absorption rate of a sitting person is about half of the rate for the same person standing with arms at the sides; the latter in turn is about half the rate for the same subject standing with arms over the head. Two-body interactions cause no increase in absorption rates for grounded people. They do, however, increase the absorption rates for subjects in an E orientation in free space; the largest interaction occurs when one subject is λ/2 behind the other (as seen by the incident wave). When these results are applied to practical occupational exposure situations, the whole-body specific absorption rate does not exceed the ANSI limit of 0.4 W/kg for exposures permitted by the ANSI standard (C95.1-1982) at frequencies from 7 to 40 MHz.
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  • 58
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 6 (1985), S. 13-32 
    ISSN: 0197-8462
    Keywords: dosimetry ; electric field ; ELF ; 60 Hz ; human ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: This paper gives current densities measured in homogeneous grounded human models exposed to vertical, 60-Hz electric fields. The methods used for these measurements were validated by measuring the current densities induced in a grounded hemisphere and in a grounded prolate hemispheroid; agreement between measurement and theory was good. For an unperturbed field strength of 10 kV/m, current densities measured in the human chest were in the range 125-300 nA/cm2. A strong horizontal current-density enhancement was observed in the axillae, with peak values of about 400 nA/cm2. The vertical current density in the arms, when held downward, was in the opposite direction to that in the chest. Current densities in the abdomen, pelvis, and legs were a strong function of whether the body was grounded through one or both feet. With one foot grounded, the horizontal current density in the lower pelvic region, just above the crotch, was 770 nA/cm2. This value was the largest of those measured in the head, arms, or torso of the human model. Scaling factors derived from these data and similar data for animals will provide a quantitative basis for comparing animal and human exposure to 60-Hz electric fields. In addition, current-density data given in this paper can be directly extrapolated to higher frequencies, at least to 1 MHz. These extrapolated data may be useful to individuals and groups involved in the determination of safety standards for the lower radiofrequency region.
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  • 59
    Electronic Resource
    Electronic Resource
    Springer
    Methods in cell science 9 (1985), S. 53-60 
    ISSN: 1573-0603
    Keywords: human ; prostatic ; epithelial ; subculture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Techniques for the isolation, establishment, and subculture of normal, benign hyperplastic and malignant epithelial cell cultures from adult human prostates are described. Acini are released from tissues by collagenase digestion, and primary and subcultures are grown in collagen-coated dishes containing medium PFMR-4A supplemented with 1% serum and additional factors. Growth assays can be performed in serum-free medium. Verification of the cultures as prostatic epithelial cells is accomplished by indirect immunofluorescence detection of keratin, prostate-specific antigen, and prostatic acid phosphatase.
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  • 60