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  • Life and Medical Sciences  (5)
  • Organic Chemistry  (4)
  • Magnetic resonance imaging  (3)
  • 1
    ISSN: 0897-3806
    Keywords: myocardium ; transcoronary ablation ; anterior interventricular artery ; Life and Medical Sciences ; Miscellaneous Medical
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The aim of this study is to determine the anatomical explanation for the greater or lesser vulnerabilities of the left ventricular segments in the event of occlusion of each of the main coronary arteries. To this end, we analyzed the arterial perfusion of 1,080 left ventricular segments from 90 human hearts obtained at autopsy. Post-mortem angiography, dissection, and constriction of an arterial map using the classification of Selvester et al. (1982) were applied. By careful monitoring of the arterial perfusion of each segment we conclude that (1) obstruction of the anterior interventricular artery (AIV) especially affects the superomesial, superoapical, and anteroapical segments; (2) obstruction of the circumflex artery (CX) especially affects the posterobasal and posteromesial segments; and (3) obstruction of the right coronary artery (RC) especially affects the inferobasal and inferomesial segments. Vulnerability of the myocardially segments decreases in those segments which have collateral supply, i.e., those which are only relatively dependent upon a particular coronary artery. © 1994 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
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  • 2
    ISSN: 1432-1459
    Keywords: White matter ; Magnetic resonance imaging ; Alzheimer's disease ; Corpus callosum ; Signal hyperintensity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We have previously demonstrated with MRI that as well as marked white matter involvement in late-onset Alzheimer's disease (AD), atrophy of the corpus callosum may also be present. This finding prompted us to study possible correlations between atrophy of the corpus callosum and white matter hyperintensity (WMH) and between white matter lesions and the severity of the disease. We compared the corpus callosum and white matter lesions on MRI from 15 AD patients and 15 controls. The white matter lesions were scored according to the Scheltens' rating scale. We found a significant reduction of the area of the corpus callosum and more severe white matter lesions in AD patients than in controls. Both atrophy of the corpus callosum and the severity of lesions depended mainly on the diagnosis of senile dementia of the Alzheimer type and on age but not on the diagnosis of presenile AD. We demonstrated a negative correlation between white matter lesions scores and areas of corpus callosum in AD patients and no correlation between the white matter lesions and the severity of the disease. We demonstrated that white matter lesions including WMH and atrophy of the corpus callosum are more frequent in AD than in controls. The predominance of white matter lesions in senile AD may be explained by the combination of aging and disease processes.
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  • 3
    ISSN: 1432-1459
    Keywords: Herpes simplex virus encephalitis ; Amygdala Hippocampus ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The long-term neuropsychological and psychiatric sequelae of herpes simplex virus encephalitis (HSVE) and their relationship to the volume of temporal lesions and to amygdala and hippocampus damage remain undefined. We have conducted a prospective study of longterm sequelae in 11 patients with clinically presumed HSVE and detection of HSV DNA in the cerebrospinal fluid by polymerase chain reaction. Six months after encephalitis, patients underwent neuropsychological and language assessment. At the same stage, single photon emission computed tomography (SPECT) evaluated the occurrence of hypoperfusion with an index of asymmetry. MRI was used for the measurement of amygdala, hippocampus and cerebral lesions by two blind neurologists. The volume of the amygdala and hippocampus was compared with those of five controls, matched for age and level of education. Longterm memory disorders were seen in 6 patients, associated with the larger lesions and damage of at least two structures. Long-term behavioural changes with emotionalism, irritability, anxiety or depression were prominent in 7. Left prefrontal hypoperfusion appeared in 8 patients, associated with psychiatric disorders in 7 and left amygdala damage in 6. The reduction of amygdala and hippocampus volume was correlated with the overall volume of lesions. Different patterns of mesial temporal lobe damage occurred, involving either amygdala alone, or amygdala and hippocampus, but never hippocampus alone. MRI volumetric measurements in HSVE could be a good indicator of long-term prognosis. Persistant behavioural changes could be related to an amygdala and frontal dysfunction.
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  • 4
    ISSN: 0730-2312
    Keywords: monoclonal antibody DWP ; activated ras protein reactive antibody ; anti-ras antibodies ; anti-ras monoclonal antibody ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Activated ras transforming genes have been described in a variety of neoplasms and encode 21,000-Dalton (p21) proteins with amino acid substitutions at positions 12, 13, and 61. In this report we describe a monoclonal antibody designated DWP that reacts. Specifically with synthetic dodecapeptides containing valine at position 12, to a lesser extent with peptides containing cysteine at position 12 and not with peptides containing glycine, arginine, serine, aspartic acid, glutamic acid or alanine at the same position. Western blot and immunoperoxidase studies showed that DWP specifically reacts with activated rasH or rasK proteins in NIH cells transformed by DNA from the human carcinoma cells that encode valine at position 12. DWP did not react with normal p21s encoding glycine at position 12, nor with activated p21s encoding aspartic acid, glutamic acid, arginine, serine, or cysteine at position 12. A survey of human tumor cell lines demonstrated that DWP reacted with the human bladder carcinoma cell line T24 but not with human tumor cell lines previously shown td contain other activating mutations at positions 12 or 61. DWP and perhaps additional antibodies that specifically react with alterations at positions 12 or 61 of the ras protein may be valuable in determining the presence and frequency of activated ras proteins in human malignancy.
    Additional Material: 3 Ill.
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  • 5
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Development of ciliated (CC) in the fetal human trachea was studied by light and electron microscopy in specimens obtained from 45 embryos or fetuses aged from 9 to 27 weeks of gestation (menstrual age). Four stages could be recognized during tracheal development. Up to 11 weeks (stage I), the trachea was covered with a columnar undifferentiated epithelium with abundant glycogen, apical microvilli, and primary cilia. From 12 to 18-19 weeks (stage II), centriolo-genesis and secondary ciliogenesis were very active, and the percentage of CC and secretory cells (SC) progressively increased. From 20 to 22-23 weeks, the density of CC was higher but, in parallel, the percentage of SC decreased (stage III). Throughout this period, the different steps of ciliogenesis could be identified in the same field, and the ciliated borders consisted of ciliary shafts with a disorderly arrangement. Megacilia were identified. Some of the preciliated cells had both cilia and secretory granules in their apical cytoplasm. After 24 weeks (stage IV), the ciliated border was apparently mature, the rootlets lengthened, and the cilia were correctly orientated. Whatever the fetal age, the density of CC was significantly higher (P 〈 .01) in the dorsal trachea compared to the ventral trachea. There are many similarities between animal and human ciliogenesis, but in human fetuses, most of the ciliary differentiation occurs early, during the first half of gestation. As demonstrated in experimental models, SC likely play a major role in genesis of CC during the fetal development of the human trachea.
    Additional Material: 12 Ill.
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  • 6
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A study of the isthmus and ligament in unionid mussels was undertaken employing methods specifically designed to preserve the in vivo relationships of these interrelated structures. Serial sections of the hard and soft tissues were used for two-dimensional analysis. From these, a tridimensional computerized reconstruction was developed. Special dissections of the undisturbed isthmus were also utilized. By using such methodologies, a new description of the ligament has been developed employing such terminology as the foliated ligament and the posterior folding laminae. Similarly, for the isthmus, an anterior lyre, a pallial crest, a pallial peduncle, and a posterior lyre are described. Such entities are both morphologically and physiologically related to the shell and ligament.
    Additional Material: 9 Ill.
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  • 7
    ISSN: 1432-1920
    Keywords: Key words Spinal cord, central canal ; Syringomyelia ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The central canal of the spinal cord is present at birth and becomes progressively obliterated. Cadaver studies have shown that it may persiste partially or completely. To our knowledge, this entity has not been described on MRI. We reviewed 794 MRI studies of the spinal cord, and found 12 patients (aged 14 to 65 years) who had an intramedullary cavity. The cavity was at the junction of the ventral 1/3 and dorsal 2/3 of the spinal cord, except at the level of the lumbar enlargement, where it was central. It was filiform in most cases, although sometimes fusiform (3 to 4 mm in diameter), and had regular contours. The cavity were thoracic in 69 % of cases. The clinical features were totally unrelated to the image, and there were no anatomical factors (Chiari malformation, dysraphism) predisposing to syringomyelia. The images were perfectly compatible with a persistent central canal, which we interpret as a variant of normal anatomy. Therefore it is important to regard these findings as normal, to avoid unnecessary treatment and follow-up.
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  • 8
    ISSN: 0749-503X
    Keywords: Heterologous gene expression ; levansucrase precursor ; Bacillus subtilis ; yeast ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Levansucrase, a Bacillus subtilis extracellular enzyme, was not secreted in the culture medium when produced in yeast. The protein accumulated inside the cell in its precursor form which represented 0·3% of total proteins. The absence of any post-translational modifications, such as signal sequence cleavage or addition of N-linked sugars, indicated that this protein did not enter the reticulum secretion pathway.Direct observation of the cells by confocal laser scanning microscopy showed that levansucrase was associated with the cytoplasmic membrane. Subcellular fractionation experiments revealed that levansucrase precursor form is associated with membranes through weak ionic interactions. The purified precursor displayed the same catalytic properties as levansucrase secreted by B. subtilis. Thus yeast could be used as a source of levansucrase precursor allowing its isolation as a pure form on a milligram scale.
    Additional Material: 8 Ill.
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  • 9
    ISSN: 0899-0042
    Keywords: solvent ; basic medium ; competitive solubilities ; optimization ; optical resolution ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Several preparative resolutions of 5,5-disubstituted hydantoins have been achieved via fractional crystallization of diastereoisomeric salts. The process can be extended by making use of the difference between the variation of solubilities of the hydantoins and their salts with α-methylbenzylamine as a function of the alkalinity of the medium. Optimization for each resolution procedure involves a refinement of the excess amount of base needed. © 1992 Wiley-Liss, Inc.
    Additional Material: 2 Ill.
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  • 10
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction of Phenyldiazomethane with 1,3-Thiazole-5(4H)-thiones: Base-Catalyzed Ring Opening of the Primary AdductReaction of 1,3-thiazole-5(4H)-thiones 1 and phenyldiazomethane (2a) in toluene at room temperature yields the thiiranes trans- and cis-1,4-dithia-6-azaspiro[2.4]hept-5-enes (trans- and cis-4; Scheme 2). With Ph3P in THF at 70°, these thiiranes are transformed stereospecifically into (E)- and (Z)-5-benzylidene-4,5-dihydro-1,3-thiazoles 5, respectively. In the presence of DBU, 1 and 2a react to give 1,3,4-thiadiazole derivatives 6 or 7 via base-catalyzed ring opening of the primary cycloadduct (Scheme 3). In the case of 2-(alkylthio)-substituted 1,3-thiazole-5(4H)-thiones 1c and 1d, this ring opening proceeds by elimination of the corresponding alkylthiolate, yielding isothiocyanate 7. The structures of (Z)-5c and 6b have been established by X-ray crystallography.
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