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2.
The effect of arabinofuranosylcytosine on the growth cycle of simian virus 40   总被引:13,自引:0,他引:13  
J S Butel  F Rapp 《Virology》1965,27(4):490-495
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3.
To compare human immunodeficiency virus (HIV) type 1 disease progression in patients infected by the predominant strain circulating recombinant form (CRF) 02_AG in western and west-central Africa and in patients infected by other strains, a prospective multicenter cohort study was conducted in Cameroon and Senegal. Among the 335 patients, a broad HIV-1 group M subtype diversity was observed in the envelope V3-V5 region, but strain CRF02_AG predominated in both Cameroon and Senegal (61.2% and 62.9%, respectively; P<.8). Multivariate analyses showed no difference between patients infected by CRF02 strains and those infected by other strains in terms of survival (adjusted hazards ratio [HR], 1.16; 95% confidence interval [CI], 0.76-1.78; P=.5), clinical disease progression (HR, 0.79; 95% CI, 0.50-1.25; P=.3), or square root CD4 cell decline (regression coefficient, -0.01; 95% CI, -0.82 to 0.81; P=.9). This study suggests that the predominance of HIV-1 CRF02_AG strain in western and west-central Africa should have no major clinical consequences.  相似文献   
4.

Objective

To evaluate content and face validity of a collaboration readiness assessment tool developed to facilitate collaborative efforts to implement policy, systems, and environment changes in Supplemental Nutrition Assistance Program–Education (SNAP-Ed).

Methods

Evaluation of the validity of the tool involved 2 steps. Step 1 was conducted with 4 subject matter experts to evaluate content validity. Step 2 used an iterative cognitive testing process with 4 rounds and 16 SNAP-Ed staff and community partners to evaluate face validity.

Results

Subject matter experts found that survey items appropriately matched the content area indicated and adequately covered collective efficacy, change efficacy, and readiness. Cognitive testing with SNAP-Ed staff and partners informed modifications and resulted in adequate face validity.

Conclusions and Implications

The ability to measure collaboration readiness will allow agencies and community partners that implement SNAP-Ed to target areas that facilitate collaboration efforts needed for policy, systems, and environment change and collective efficacy. Further cognitive testing of the tool with other populations is needed to ensure its applicability and usefulness. Evaluation of the reliability of the tool with a broad range of SNAP-Ed programs and community agencies is also recommended.  相似文献   
5.
Over several decades the incidence of allergy has been increasing dramatically in the industrialised world. Amongst other factors this increase is related to a defect in the component of maturation of the immune system which is secondary to the presence of commensal bacteria. Increased hygiene and frequent use of antibiotics are responsible for modifying the process of installation of the population of intestinal micro-organisms during the first months of life. This is the theoretical basis for the use of probiotics and prebiotics with the intention of modulating the microbial population to prevent and treat allergy, a strategy which is stimulating a great deal of interest. The present review is designed to present an update on randomised, double blind clinical studies with administration of pro- and/or prebiotics in the treatment or prevention of allergy. Some studies have yielded promising results. Even though the present state of knowledge does not enable us to recommend the use of probiotics in the treatment or prevention of allergy, this approach is, nevertheless, an attractive one and should be pursued.  相似文献   
6.
We conducted experiments to determine if p53 alterations, which are frequent in human breast cancers, were also common in murine mammary tumors. In 13 mammary tumors from 7,12-dimethylbenz[a]anthracene (DMBA)-treated BALB/c mice were immunohistochemically analyzed for overexpression of p53; p53 protein was not detectable. Three of the tumors were established as cell lines in vitro. p53 protein was rarely detected at passage 4 in these lines but was overexpressed by passage 8 in two of them. The p53 nucleotide sequence was shown to be wild type in one primary mammary tumor and in the two p53-overexpressing cell lines. One cell line that overexpressed p53 in vitro was implanted into BALB/c mice. The resulting tumors retained the wild-type p53 nucleotide sequence but no longer expressed detectable levels of p53 protein, suggesting that the overexpression of wild-type p53 was related to in vitro culture conditions. The effect of DMBA on mammary-tumor development was also tested in mice rendered hemizygous for p53. These mice and wild-type littermate controls had no differences in susceptibility to induction of mammary tumors by oral administration of DMBA. Furthermore, Southern blot hybridizations detected no gross alterations in the wild-type p53 allele in mammary tumors from the p53-deficient mice. Point mutation of the wild-type p53 allele was also infrequent in the DMBA-induced mammary tumors from hemizygous p53 mice; it occured in only one of seven tumors. Thus, the p53 gene is apparently not a primary target for genetic alterations in DMBA-induced mammary tumors. Next, we examined mammary tumors derived from D1 and D2 transplantable hyperplastic alveolar nodule (HAN) outgrowths, which rapidly form tumors containing Ha-ras mutations after DMBA treatment. As ras and p53 mutants can cooperate in transformation, we examined whether D1 and D2 HAN outgrowths have p53 mutations. Unlike in the DMBA-induced primary mammary tumors, nuclear p53 accumulation was observed frequently (10 of 14) in tumors that arose from D1 and D2 HAN outgrowths. Direct sequencing of the entire coding region of the p53 cDNA from six D1 and D2 tumors confirmed that the sequence was wild type. Although wild-type p53 was retained in both DMBA-induced mammary tumors and mammary tumors derived from D1 and D2 preneoplastic outgrowths, wild-type p53 overexpression was detected only in D1 and D2 tumors. Therefore, D1 and D2 tumors appear to arise by a pathway in which p53 expression is altered, whereas DMBA induction affects a different pathway that does not require such alteration. © 1994 Wiley-Liss, Inc.  相似文献   
7.
From 1955 through early 1963, millions of people were inadvertently exposed to simian virus 40 (SV40) as a contaminant of poliovirus vaccines; the virus had been present in the monkey kidney cultures used to prepare the vaccines and had escaped detection. SV40 was discovered in 1960 and subsequently eliminated from poliovirus vaccines. This article reviews current knowledge about SV40 and considers public responses to reports in the media. SV40 is a potent tumour virus with broad tissue tropism that induces tumours in rodents and transforms cultured cells from many species. It is also an important laboratory model for basic studies of molecular processes in eukaryotic cells and mechanisms of neoplastic transformation. SV40 neutralizing antibodies have been detected in individuals not exposed to contaminated poliovirus vaccines. There have been many reports of detection of SV40 DNA in human tumours, especially mesotheliomas, brain tumours and osteosarcomas; and DNA sequence analyses have ruled out the possibility that the viral DNA in tumours was due to laboratory contamination or that the virus had been misidentified. However, additional studies are necessary to prove that SV40 is the cause of certain human cancers. A recently published review article evaluated the status of the field and received much media attention. The public response emphasized that there is great interest in the possibility of health risks today from vaccinations received in the past.  相似文献   
8.
BACKGROUND: Excretion of fecal short-chain fatty acids (SCFAs) may indicate changes in colonic or colonocyte metabolism. The aim of this study was to detect the influence of gestational age and feeding practices on SCFA concentrations and profiles in healthy preterm infants. METHODS: A total of 198 fecal samples (28 infants) were collected from 8 to 21 days of age from 3 groups of preterm infants born at 33 to 37 weeks of gestation and fed either breast milk (group I) or Nutramigen, a lactose-free formula (group II), and extremely preterm infants born before 33 weeks of gestation and fed breast milk (group III). Total SCFA concentrations and SCFA profiles were analyzed using a gas chromographic (GC) procedure. RESULTS: Total fecal SCFA excretion did not differ significantly between group I (mean, 24.0 micromol/g; range, 1.3 to 118.8 micromol/g) and group II (mean, 23.0 micromol/g; range, 3.0 to 73.3 micromol/g). Conversely, differences occurred between SCFA profiles and became significant after day 17. The main differences were a significant increase in the butyric acid concentration (12% versus 30%) with group II. Compared with group I, fecal SCFA concentrations were 3.2-fold lower (7.4 micromol/g; range, 0.3 to 37.4 micromol/g) in group III with no significant changes in the profiles. CONCLUSIONS: Fecal SCFA excretion may vary in absence of any digestive disease. During this study, in terms of gestational age, total SCFA concentrations were significantly lower in extremely premature infants compared with infants born less premature, despite their known higher deficiency in intestinal lactase activity. In terms of diet, the absence of lactose did not lead to a decrease in colonic fermentation and induced changes in SCFA patterns. These new baseline data may offer clues to further development of milk formulas.  相似文献   
9.
Five continuous mouse mammary tumor cell lines and 12 clonal derivatives have been established from tumors arising in BALB/c or C3H mice either spontaneously or in response to viral (mammary tumor virus), hormonal (17 beta-estradiol), or chemical [7,12-dimethylbenz(alpha)anthracene] stimuli in vivo. The cell lines were examined for the following in vitro growth parameters:plating efficiency, saturation density, population-doubling times, colony formation on plastic surfaces, and anchorage-independent growth in methylcellulose. The majority of the mammary tumor cell lines were transplantable in syngeneic, immunocompetent mice and gave rise to tumors composed of epithelial cells. There was no growth parameter in vitro which invariably correlated with tumorigenicity in vivo. Most of the mammary tumor cell lines appeared to produce C-type virus. Only one, a C3H derivative, appeared to respond to stimulation by glucocorticoids with the enhanced production of B-type virus. Analysis of the growth properties exhibited in culture by transformed mammary epithelial cells revealed marked differences from those previously reported for transformed fibroblasts.  相似文献   
10.
BACKGROUND: Between 1955 and 1963, millions of individuals worldwide received vaccines contaminated with polyomavirus simian virus (SV)40. Recent data suggest that some individuals may develop renal dysfunction related to SV40 infection, including individuals too young to have received contaminated vaccines. CASE REPORT AND RESULTS: Three years after bilateral lung transplantation, a 32-year-old man with cystic fibrosis developed nephrotic syndrome and progressed to end-stage renal failure over 1.5 years. He was shown to have nephropathy caused by SV40. The diagnosis was documented by detecting and confirming sequences of SV40 (but not BK or JC virus) in his kidney biopsy and urine by polymerase chain reaction, Southern blot, and DNA sequencing. Positive immunohistochemistry for SV40 was found in his kidney, and neutralizing antibodies for SV40 were detected in his serum, before and after the onset of renal dysfunction. A source for the virus was not determined. His household contacts did not have serologic or molecular evidence of SV40 infection. No serum or tissue samples were available from his 27-year-old donor. DISCUSSION: This report shows that SV40 is circulating in the community and can cause nephropathy in transplant patients.  相似文献   
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