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  • 1
    ISSN: 1432-0738
    Keywords: Colorectal cancer ; Acetylator genotype ; Human colon ; Arylamine N-acetyltransferase ; Age effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Polymorphic expression of arylamine N-acetyltransferase (EC 2.3.1.5) may be a differential risk factor in metabolic activation of arylamine carcinogens and susceptibility to cancers related to arylamine exposures. Human epidemiological studies suggest that rapid acetylator phenotype may be associated with higher incidences of colorectal cancer. We used restriction fragment length polymorphism analysis to determine acetylator genotypes of 44 subjects with colorectal cancer and 28 non-cancer subjects of similar ethnic background (i.e., approximately 25% Black and 75% White). The polymorphic N-acetyltransferase gene (NAT2) was amplified by the polymerase chain reaction from DNA templates derived from human colons of colorectal and non-cancer subjects. No significant differences inNAT2 allelic frequencies (i.e., WT, M1, M2, M3 alleles) or in acetylator genotypes were found between the colorectal cancer and non-cancer groups. No significant differences inNAT2 allelic frequencies were observed between Whites and Blacks or between males and females. Cytosolic preparations from the human colons were tested for expression of arylamine N-acetyltransferase activity. Although N-acetyltransferase activity was expressed for each of the arylamines tested (i.e., p-aminobenzoic acid, 4-aminobiphenyl, 2-aminofluorene, β-naphthylamine), no correlation was observed between acetylator genotype and expression of human colon arylamine N-acetyltransferase activity. Similarly, no correlation was observed between subject age and expression of human colon arylamine N-acetyltransferase activity. These results suggest that arylamine N-acetyltransferase activity expressed in human colon is catalyzed predominantly by NAT1, an arylamine N-acetyltransferase that is not regulated byNAT2 acetylator genotype. The ability to determine acetylator genotype from DNA derived from human surgical samples should facilitate further epidemiological studies to assess the role of acetylator genotype in various cancers.
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  • 2
    ISSN: 1432-2307
    Keywords: Metallothionein ; Breast cancer ; Immunohistochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Metallothionein (MT) is a cysteine-rich, low molecular weight protein that binds zinc, copper, and cadmium. It is present in a number of normal cells including hepatocytes particularly during fetal and early postnatal life. It has been suggested that developmental profile of MT is similar to other oncofetal gene products and hence, it could be used as a marker for aggressive tumour behaviour. In order to test that hypothesis, we used a monoclonal antibody to MT and immunohistochemically evaluated formalin-fixed, paraffin-embedded tissues from 79 breast carcinomas. In non-neoplastic breast tissue, a strong nuclear and cytoplasmic staining was observed in myoepithelial cells. Positive staining for MT was present in 35 (44%) of breast carcinomas. In most positive cases, nuclear, or both nuclear and cytoplasmic staining was seen. All positive tumours were invasive ductal carcinomas, including a medullary and a metaplastic carcinoma. None of the mucinous, lobular, or intraductal papillary carcinomas reacted for MT. A statistically significant association was found between MT immunostaining and histological grade (P〈0.01) as well as with nuclear grade (P〈0.01). We also observed an inverse relationship between MT staining and oestrogen receptor content of tumours (P〈0.01). Similarly, a statistically significant association was found between moderate and strong MT immunostainig and decreased overall survival and shorter disease-free survival (P〈0.01). MT immunostaining was also predective of a worse prognosis in the subgroup of lymph node negative (P〈0.001) and oestrogen receptor negative patients (P〈0.01). No statistically significant association was found between MT staining and size of tumour or the presence of lymph node metastasis. We conclude that MT staining may be a useful marker of less differentiated and more aggressive carcinomas of the breast.
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  • 3
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: Neurostatin was originally described as an inhibitor of astroblast and astrocytoma division present in rat brain extracts and immunologically related to the sugar moiety of epidermal growth factor receptor and to blood group antigens. It was purified recently from mammalian brain extracts and characterized as a glycosphingolipid, but its precise structure remained unknown. Neurostatin has now been purified to apparent homogeneity from ganglioside extracts of rat, bovine, and porcine brain. It is cytostatic for astroblasts, C6 glioma cells, and various human astrocytomas grades III and IV, with IC50 values ranging from 250 to 450 nM, but does not affect the division of primary or transformed fibroblasts up to concentrations 〉4 μM. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry of purified pig neurostatin showed a molecular ion of 1,905 Da and ions of 1,863 and 1,934 Da, compatible with a disialoganglioside. Mono- and bidimensional NMR spectra, together with biochemical studies, suggest that neurostatin may be the 9-O-monoacetyl ester of GD1b.
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  • 4
    ISSN: 1399-3038
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Few epidemiological studies have compared the risk factors of asthma or wheezing between atopic and non-atopic children. The objective of this study was to determine if there are specific risk factors for current wheezing related to atopic status in schoolchildren. Schoolchildren 9–12 yr of age from three Spanish cities (n = 2720) were subject to a cross-sectional study of asthma risk factors (by questionnaire) and atopy (by skin prick test) according to the ISAAC phase-II protocol. Risk factors for current wheezing (in the last 12 months) as reported by parents were investigated among the atopic (positive prick test to at least one allergen) and the non-atopic (negative prick test) children. The prevalence of current wheezing was 13.1% in the whole group, 22.1% in the atopic group and 7.8% in the non-atopic group. However, only 62.4% of children with current wheezing were atopic. Male gender and asthma in the mother and/or the father were both significant and independent risk factors for current atopic wheezing, whereas maternal smoking in the first year of the child's life and mould stains on the household walls were for current non-atopic wheezing. In summary, this study shows that atopic and current non-atopic wheezing children in Spain do not share identical environmental and family risk factors.
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  • 5
    ISSN: 1399-3038
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The objective of this study was to determine the level of adherence of pediatricians in Spain to the Spanish National Guidelines for Asthma Treatment with regard to the use of a peak flow meter (PEFR) or a spirometer in the diagnosis and management of asthma in childhood and to analyze sources of variations in these practices. A prospective survey (consisting of demographic and asthma knowledge sections) was conducted over a 2-wk time interval of 3000 pediatricians throughout the country. At least one part of the questionnaire was completed and returned by 2773 individuals (92.4%), with 2347 (78.2%) answering both sections; results are for this population. Around 62% of the pediatricians reported having a peak flow meter or a spirometer in their office; however, only 33% and 48% of them used the devices for the diagnosis and treatment of asthma, respectively. There was a significant association between being older (36–55 yr old) and using PEFR or spirometry for the diagnosis (OR: 1.35, 95% CI 1.11–1.66) and the management (OR 1.47, 95% CI 1.22–1.77) of asthma. Males used a peak flow meter or a spirometer more often than females for the diagnosis (37.8% vs. 30.9%, p = 0.001) and management of asthma (52.0% vs. 45.6%, p = 0.008). Pediatricians with formal pediatric residence training used these devices more for the diagnosis (OR: 1.39, 95% CI 1.09–1.75) and management (OR: 1.58, 95% CI 1.27–1.96) than those without. Working in a hospital was also related with more peak flow meter or spirometer use than working in health centers (OR: 2.08, 95% CI 1.71–2.54 for diagnosis; OR: 1.83, 95% CI 1.50–2.22 for management). About one-third of the Spanish pediatricians surveyed use spirometers and/or peak flow meters for diagnosing asthma and about half use one of these devices occasionally for managing the disease. Independent factors favoring their use are: age 36–55 yr, male gender, working in a hospital setting, and having been trained in a formal pediatric residence program.
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  • 6
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 322 (1986), S. 811-814 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The zonal mean transport in the lower stratosphere normally takes the form of a two-cell diabatic circulation, with rising motion in the tropics and subsidence near both poles6"10. For a species such as O3, whose source is in the stratosphere, upward transport tends to reduce its column abundance, ...
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  • 7
    ISSN: 1617-4623
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The temperature sensitive rna2 mutation of Saccharomyces cerevisiae causes a rapid and dramatic decrease in the abundance of most ribosomal protein mRNAs [6, 14]. We and others have recently shown that the processing of ribosomal protein mRNAs is defective at the nonpermissive temperature, suggesting that inefficient mRNA processing might be responsible for the decline in ribosomal protein mRNA levels [2, 4, 8, 11]. Actin is the only known intron-containing non-ribosomal protein yeast nuclear gene [5, 10]. We show here that the processing of actin mRNA is also defective at the nonpermissive temperature in rna2-containing strains. The observation supports the notion that all intron-containing genes are affected in a similar fashion by the rna2 mutation.
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  • 8
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 352 (1991), S. 134-137 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Previous calculations5'7 indicated that the observed ozone trends at northern high latitudes in winter could be a result of heterogeneous chemistry occurring in arctic polar stratospheric clouds (PSCs). Ozone at lower latitudes could also be affected by processes occurring outside the polar ...
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  • 9
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Accounts of chemical research 28 (1995), S. 477-478 
    ISSN: 1520-4898
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
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