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991.
A World Federation of Hemophilia External Quality Assessment Scheme has been established to promote high standards of laboratory performance in haemophilia centres worldwide. Results from 21 International Haemophilia Training Centres (IHTCs) provide target values for the prothrombin time (PT), activated partial thromboplastin time (APTT), factor VIII:C, IX:C and von Willebrand factor (VWF) assays, against which the performance of Haemophilia Centres in developing countries (HCs) can be assessed. Eight surveys were distributed over a 3-year period between 1994 and 1997. A higher proportion of HCs failed to identify an abnormal PT or APTT in samples from donors with mild deficiencies of the extrinsic and intrinsic systems, respectively. For factor VIII:C and IX:C assays, agreement between HC results was consistently poorer than between IHTCs. However, improvement in between-centre agreement could be seen for two samples distributed on more than one occasion. A minority of HCs perform assays for VWF, and a questionnaire revealed equipment and reagent costs as limiting the range of assays which could be carried out in several centres. However, agreement was in some cases better between those HCs that did perform VWF assays than between IHTCs. The problems of screening test sensitivity and between-centre agreement for factor assays need to be addressed, together with the limitations which prevent HCs from performing a full range of tests in the diagnosis and treatment of bleeding disorders. 相似文献
992.
SJ Blalock M Orlando EJ Mutran RF DeVellis BM DeVellis 《Canadian Metallurgical Quarterly》1998,11(3):158-165
An improved procedure for the synthesis of 3 beta-hydroxyandrost-5-ene-7,17-dione, a natural metabolite of dehydroepiandrosterone (DHEA) is described. The synthesis and magnetic resonance spectra of several other related steroids are presented. Feeding dehydroepiandrosterone to rats induces enhanced formation of several liver enzymes among which are mitochondrial sn-glycerol 3-phosphate dehydrogenase (GPDH) and cytosolic malic enzyme. The induction of these two enzymes, that complete a thermogenic system in rat liver, was used as an assay to search for derivatives of DHEA that might be more active than the parent steroid. Activity is retained in steroids that are reduced to the corresponding 17 beta-hydroxy derivative, or hydroxylated at 7 alpha or 7 beta, and is considerably enhanced when the 17-hydroxy or 17-carbonyl steroid is converted to the 7-oxo derivative. Several derivatives of DHEA did not induce the thermogenic enzymes whereas the corresponding 7-oxo compounds did. Both short and long chain acyl esters of DHEA and of 7-oxo-DHEA are active inducers of the liver enzymes when fed to rats. 7-Oxo-DHEA-3-sulfate is as active as 7-oxo-DHEA or its 3-acetyl ester, whereas DHEA-3-sulfate is much less active than DHEA. Among many steroids tested, those possessing a carbonyl group at position 3, a methyl group at 7, a hydroxyl group at positions 1, 2, 4, 11, or 19, or a saturated B ring, with or without a 4-5 double bond, were inactive. 相似文献
993.
Increasing Kaposi's sarcoma-associated herpesvirus seroprevalence with age in a highly Kaposi's sarcoma endemic region, Zambia in 1985 总被引:1,自引:0,他引:1
SJ Olsen Y Chang PS Moore RJ Biggar M Melbye 《Canadian Metallurgical Quarterly》1998,12(14):1921-1925
BACKGROUND: Kaposi's sarcoma (KS)-associated herpesvirus (KSHV) is a newly discovered virus found in all forms of KS. In the United States, KSHV infection appears to be most common amongst individuals at high-risk for KS. Preliminary data from Africa suggest that KSHV infection may be much more common in the general population. OBJECTIVE: To examine the KSHV seroprevalence and age-specific patterns of infection in an African country with high rates of KS. DESIGN: Cross-sectional seroprevalence study. METHODS: Sera were taken for a hospital-based HIV seroprevalence study conducted in August 1985 in Lusaka, Zambia at a time when HIV was just becoming epidemic in this area. A total of 251 sera were randomly sampled and examined for antibodies against latent and lytic antigens to KSHV. KSHV seroprevalence was compared with demographic and clinical variables using chi2 test for linear trend and odds ratios and 95% confidence intervals. RESULTS: Overall, 58% of persons aged 14-84 years were KSHV-seropositive. KSHV seroprevalence increased linearly with age (P = 0.04) and was inversely related to years of education (P = 0.015). In contrast, HIV infection peaked in those aged 20-29 years and was positively related to years of education (P = 0.01 5). No association between KSHV and gender, marital status, or HIV serostatus was seen. CONCLUSIONS: KSHV infection was significantly more common in this region of Zambia in 1985 than it currently is in the United States. Our data are consistent with KSHV being well-established in this region prior to 1985 and that continued adult transmission of the virus was occurring. The high seroprevalence in the adolescent age-group and the relatively linear increase in prevalence with age suggest that non-sexual modes of transmission may be important for KSHV transmission in Africa. 相似文献
994.
AJ Gamboa-Pinto CL Rock MG Ferruzzi AB Schowinsky SJ Schwartz 《Canadian Metallurgical Quarterly》1998,128(11):1933-1936
Results from epidemiologic studies suggest that a carotenoid-rich diet may reduce risk for cervical cancer, possibly by inhibiting the progression of cervical intraepithelial neoplasia, a preneoplastic lesion of the cervical tissue. Laboratory studies suggest that the mechanism may be linked to the metabolism of carotenoids to retinoic acid or retinoic acid-like compounds, which has been hypothesized to occur in the cervical tissue. The purpose of this study was to demonstrate the presence of provitamin A carotenoids in biopsied samples of this peripheral tissue in human subjects and to examine the relationship between baseline concentrations of these carotenoids in plasma and normal cervical tissue in subjects who were being evaluated for possible participation in a diet intervention trial. Subjects were 13 women aged 19-41 y. With the use of HPLC methodology, plasma concentrations of alpha-carotene, beta-carotene and beta-cryptoxanthin were determined with UV/visible light detection for plasma and electrochemical detection for cervical tissue. Relationships between plasma and cervical tissue were evaluated with Pearson correlation analysis. Adjusted for plasma cholesterol concentration, plasma alpha-carotene and beta-carotene were correlated with cervical tissue concentrations (r = 0.91, P < 0.001; r = 0.90, P < 0.001; respectively). Adjusted for plasma cholesterol concentration, plasma beta-cryptoxanthin tended to be correlated with cervical tissue concentrations (r = 0.62, P = 0.058). These findings suggest that plasma concentrations of alpha-carotene and beta-carotene are good predictors of cervical tissue concentrations of these compounds in human subjects and describe a first step toward demonstrating a biological link between provitamin A carotenoids and cervical cancer in vivo. 相似文献
995.
The authors previously reported that male offspring of mothers rats given alkaline ionized water (AKW) showed a significantly higher body weight by day 14 after birth than did offspring of mother rats given tap water (TPW); furthermore, marked myocardial necrosis and fibrosis were observed particularly in the former male offspring at the age of 15 weeks. In the present experiment we looked for differences in bioparameters, namely the milk yield of mothers and suckled milk volume of the offspring, between the AKW- and the TPW-treated groups in order to reveal the factors which cause the unusual body weight gain in the offspring. Even though we were able to repeat our previous observation (the body weight of the male offspring of the AKW group increased significantly more by day 14 and 20 after birth and of the female by day 20 after birth than did that of the TPW group (p < 0.05), no significant difference was noted in any of the bioparameters, including those related to milk production and consumption. It is thus suspected that the water-hydrated cation, which was transferred either to the fetus through the placenta or to the offspring through the milk, might be the cause of the unusual body weight increase. Since calcium plays an important role in skeletal formation, it is tentatively concluded that the higher calcium concentration of AKW enriched the mother, serum calcium which was transferred to the fetus through the placenta and to the offspring through the milk. 相似文献
996.
OBJECTIVES: We studied the clinical spectrum, histology, and malignant potential of colonic polyps in Indian children (< or =12 yr). METHODS: Two hundred thirty-six children with colonic polyps were studied from January 1991 to October 1996. They were evaluated clinically and colonoscopic polypectomy was done. Children with five or more juvenile polyps were labeled as having juvenile polyposis and serial colonoscopic polypectomies were done every 3 wk. Colectomy was performed when there were intractable symptoms or clearing of the polyps by colonoscopy was not possible. Histological examination of the polyps was done. Follow-up colonoscopy was done in children with juvenile polyposis only. RESULTS: The mean age of these children was 6.12 +/- 2.7 yr, with a male preponderance (3.5:1). Rectal bleeding of a mean duration of 14 +/- 16 months was the presenting symptom in 98.7%. Solitary polyps were seen in 76%, multiple polyps in 16.5%, and juvenile polyposis in 7% (n = 17) of the children. A majority (93%) of the polyps were juvenile and 85% were rectosigmoid in location. Adenomatous changes, seen in 11%, were more common in juvenile polyposis (59%) than in juvenile polyps (5%). Among those with juvenile polyposis, colon clearance was achieved in eight, six required colectomy for intractable symptoms, and three were still on the polypectomy program. Polyps recurred in 5% of children with juvenile polyps and 37.5% of those with juvenile polyposis. CONCLUSIONS: Juvenile polyps remain the most common colonic polyps in children. A significant number of cases of polyps are multiple and proximally located, which emphasizes the need for total colonoscopy in all. Juvenile polyps should be removed even if asymptomatic because of their neoplastic potential. Colonoscopic polypectomy is effective even in juvenile polyposis. Surveillance colonoscopy is required in juvenile polyposis only. 相似文献
997.
MC Weinrich SJ Jacobsen SP Weinrich JW Moul JE Oesterling D Jacobson R Wise 《Canadian Metallurgical Quarterly》1998,52(6):967-973
OBJECTIVES: To determine the age- and race-specific prostate-specific antigen (PSA) distributions in healthy men in central South Carolina and to compare these to data from other studies. METHODS: Two thousand ninety-two black men aged 40 to 69 years and white men aged 50 to 69 years from the general population in 11 counties of central South Carolina participated in a prostate cancer educational program. Seventy-two percent of the participants were black-about double the proportion in the general population-and 63% of the men (1319 of 2092) subsequently obtained a PSA determination from their own physician. The distribution of serum PSA was compared with distributions from the Olmsted County study and from the Walter Reed Army Medical Center/Center for Prostate Disease Research study. RESULTS: Older men without cancer had higher PSA levels. Regression analyses yielded an associated increase of about 3.3% per year. Reference ranges for normal PSA in men without cancer (based on their sample 95th percentiles) were zero to 1.9, 3.8, and 5.7 ng/mL in black men aged 40 to 49, 50 to 59, and 60 to 69 years, and zero to 2.7 and 4.9 mg/mL in white men aged 50 to 59 and 60 to 69 years, respectively. CONCLUSIONS: Reference ranges for normal serum PSA levels should take into account the population from which they are derived and to which they will be applied. Reference ranges that are useful in the general population can differ from those that are appropriate in a hospital setting. For the general population in central South Carolina, reference ranges for serum PSA levels are lower than previously published reference ranges, particularly among black men. 相似文献
998.
999.
The results of research on rank filters are presented. The relationship of rank filters with other filters is briefly discussed. The main properties of rank filters are listed and an explanation is given for these properties. Several software and hardware implementations of the filter are described. Major applications to image processing are discussed, including noise smoothing, cluster detection, skeletization, edge enhancement and edge detection. 相似文献
1000.