The frequency of astrovirus as a cause of diarrhea in Baltimore children.
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Baltimore↗
Biomedical subjects
R W Hudson
Publications and source records attributed to R W Hudson.
Immunological characterization of the Marin County strain of astrovirus.
Marin County virus (MCV) was isolated from a stool suspension and serially propagated in human embryonic kidney cell cultures. MCV particles in stool and cell-propagated virus stocks showed reactivity by immune electron microscopy (IEM) with rabbit antiserum to astrovirus type 5. MCV antigen was also detected in two MCV stool samples by enzyme immunoassay (EIA) with an astrovirus group-specific monoclonal antibody. Acute and convalescent sera from 3 of 3 MCV-infected patients showed seroconversion to cell-propagated MCV by EIA. Immunofluorescence of MCV propagated in cell culture showed positive reactivity with an astrovirus group specific monoclonal antibody and astrovirus type 5 antiserum, with some cross-reactivity with astrovirus type 1. Similar results were obtained with the prototype strain of astrovirus type 5. However, in plaque-reduction assays, both the prototype astrovirus type 5 and MCV were neutralized by type 5 antiserum only. We conclude that MCV can be serially propagated by techniques used for previously described astroviruses and is serotypically an astrovirus type 5.
Antibodies, Monoclonal↗
Comparison of the nuclear 5 alpha-reduction of testosterone and androstenedione in human prostatic carcinoma and benign prostatic hyperplasia.
The nuclear conversion of testosterone (T) to dihydrotestosterone (DHT) and androstenedione (delta 4A) to androstanedione (5 alpha-Adione) was compared in the separated stromal and epithelial fractions of hyperplastic (n = 6) and malignant (n = 3) prostatic tissues. Assay conditions were linear with respect to time and protein concentration and were optimal for NADPH concentration. The apparent Km values for the stromal enzymes were 0.2 and 0.02 microM for hyperplasia and carcinoma, respectively, using T as substrate. The apparent Km values, using delta 4A as substrate, were 0.03 and 0.02 microM, respectively. Apparent Vmax values for the stromal formation of DHT were 16.5 +/- 5.4 and 1.97 +/- 0.45 pmol/mg protein/30 min incubation, respectively, for the hyperplastic and malignant tissues. The apparent Vmax values for the formation of 5 alpha-Adione were 2.8 +/- 1.3 and 6.5 +/- 1.2 pmol/mg/protein/30 min incubation. The apparent Km values for the epithelial enzyme, for hyperplastic and malignant tissue were 0.04 and 0.04 microM, for T, and 0.05 and 0.03 microM for delta 4A. The respective apparent Vmax values were 4.6 +/- 0.93 and 0.65 +/- 0.07 for DHT and 2.0 +/- 0.86 and 6.4 +/- 0.45 pmol/mg protein/30 min incubation for 5 alpha-Adione. delta 4A was a competitive inhibitor of T 5 alpha-reduction. These results provide further evidence that different rates of 5 alpha-reduction at least partially explain the differences in androgen levels seen in the hyperplastic and the malignant prostate.
3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
Diagnosis of astrovirus gastroenteritis by antigen detection with monoclonal antibodies.
An enzyme-linked immunosorbent assay (ELISA), based on monoclonal antibodies to the astrovirus group antigen, was designed for the detection of astroviruses in stools of patients with gastroenteritis. Compared to immune electron microscopy used as the standard test, the sensitivity of the astrovirus ELISA was 91% (31/34) and the specificity was 96% (54/56). All five of the known astrovirus serotypes could be detected in 16 samples on which serotyping was done. In tests on 155 stools containing other enteric viruses, including adenoviruses, rotaviruses, caliciviruses, Hawaii virus, Snow Mountain virus, and Norwalk virus (30, 20, 70, 24, 4, and 7 samples, respectively), only 3 were positive in the astrovirus ELISA. The combined specificity for all astrovirus immune electron microscopy-negative samples was 98% (206/211). The results demonstrate that the new ELISA provides a sensitive and specific means for the diagnosis of astrovirus gastroenteritis.
Antibodies, Monoclonal↗
Accuracy of Chlamydia trachomatis antigen detection methods in a low-prevalence population in a primary care setting.
We compared a direct fluorescent-antibody stain (DFA) and an enzyme immunoassay (EIA) with a standard cell culture technique for the detection of Chlamydia trachomatis infection in women in an urban family practice setting. We also evaluated a DFA sample in a commercial laboratory to determine the interlaboratory reliability of this test. There were 268 women in the study; the EIA provided a higher sensitivity (83 versus 50%) and a higher positive predictive value (83 versus 69%) than the DFA test and comparably high specificity (99 versus 98%). Concordance between the two laboratories on the DFA test was not high when data were adjusted for chance agreement (kappa coefficient = 0.64). DFA validity was optimal with an elementary body cutoff of greater than 5, while EIA validity was optimal at the recommended cutoff of 0.1 optical density unit. None of 11 women with negative cultures after treatment had false-positive antigen tests. False-negative results with both tests were associated with low culture inclusion counts but were not strongly associated with the presence or absence of symptoms, menses, pregnancy, or recent antibiotic use. False-positive results with EIA were seen only for three women who had a chief complaint of vaginal discharge. Although the positive predictive value of DFA could be increased in high-prevalence subpopulations, EIA was still more valid in two such groups: teenagers and prenatal patients. These results indicate that EIA might be preferable for low- or moderate-prevalence populations in primary care settings and that a falloff in DFA sensitivity could be explained by lower infection burdens in low-prevalence groups.
Adult↗
11 beta-hydroxyandrostenedione: a marker of adrenal function in hirsutism.
To assess the role of the adrenal glands in the development of hirsutism, levels of 11 beta-hydroxyandrostenedione (11 beta-OHA), 17 alpha-hydroxyprogesterone (17-OHP), dehydroepiandrosterone sulphate (DHEAS), androstenedione (delta 4A), and free and total testosterone (T) were measured in 63 hirsute females and 30 control patients. Six of the hirsute patients had basal levels of 11 beta-OHA and 17-OHP and responses to adrenocorticotropic hormone that were significantly greater than these values in controls and the other hirsute women. These women were designated as having an adrenal source for their hirsutism. Women with polycystic ovarian syndrome and idiopathic hirsutism had normal values of 11 beta-OHA and 17-OHP. Levels of total and free T, DHEAS and delta 4A were significantly higher than control values in all of the hirsute women. This study demonstrates that 11 beta-OHA can be used as a marker to assess the adrenal contribution to hirsutism.
Adrenal Glands↗
Plaque quantitation and virus neutralization assays for human astroviruses.
Astroviruses, 28 nm-diameter, RNA-containing viruses which have been implicated in gastroenteritis can be cultivated in cell cultures containing trypsin, but do not show distinguishable cytopathic effects. However, with the 5 known astrovirus serotypes which we have been able to cultivate, 3 (types 1, 2, and 5) formed well-defined plaques in LLCMK2 cell cultures under an agar overlay containing trypsin. A virus neutralization assay based on plaque reduction was applied to these 3 serotypes. It was found that rabbit antisera prepared against individual serotypes neutralized virus type-specifically, and no cross-neutralization titers were obtained with any of the antisera to the 5 astrovirus serotypes. The type-specific neutralization observed agreed with the specificities seen by immunofluorescence (IF), whereas ELISA tests with the same antisera show cross-reactivity among all 5 serotypes. There was no virus neutralization detected with astrovirus monoclonal antibodies which were reactive with 5 serotypes by ELISA and IF. The results we have obtained permit quantitative techniques to be applied to epidemiological and biological studies of the human astroviruses.
Antibodies, Viral↗
Comparison of nuclear 5 alpha-reductase activities in the stromal and epithelial fractions of human prostatic tissue.
The nuclear conversion of testosterone (T) to dihydrotestosterone (DHT) was compared in the separated stromal and epithelial fractions of hyperplastic (n = 20), malignant (n = 5) and normal (n = 1) prostatic tissues. Standard assay conditions were: 1 microM testosterone, plus 4-6 X 10(5) DPM [3H]T, 1.0 mM NADPH, 2.0 mM EDTA and 0.5-1.0 mg nuclear protein in a total volume of 1.1 ml HEPES buffer, pH 7.4 (stroma) or MES buffer, pH 6.5 (epithelium). The apparent Km values for the stromal enzyme were 0.2, 0.2 and 0.3 microM, respectively, for the enzymes in hyperplastic, malignant and normal tissues. The Vmax values were 26 +/- 4.2, 2.8 +/- 0.6 and 4.1 pmol/mg protein/30 min incubation, respectively, for these same tissues. The apparent Km values for the epithelial enzymes, from the same tissues, were 0.03, 0.07 and 0.08 microM. The Vmax values for the epithelial enzymes were 4.8 +/- 1.2, 0.69 +/- 0.08 and 1.1 pmol/mg protein/30 min incubation. The pH optimum for the stromal enzyme lay between pH 6.5 and 7.5, whereas the pH optimum for the epithelial enzyme lay between 5.5 and 6.5. Enzymatic activity in both fractions revealed a biphasic response to zinc. In the absence of EDTA, microM quantities of zinc enhanced enzymatic activity while mM quantities inhibited this activity. These results would suggest that differences in the conversion of T to DHT help to explain, at least in part, the higher DHT levels seen in hyperplastic tissue and the higher T levels seen in the malignant prostate.
3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
Studies of 11beta-hydroxylation by beef adrenal mitochondria.
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Adrenal Glands↗
Testicular function in hyperthyroidism.
Testicular function was assessed in nine men aged 17 to 35 years and seven men aged 36 to 46 years with Graves' disease. Levels of total testosterone, estradiol, sex hormone binding globulin, luteinizing hormone, and follicle stimulating hormone, and gonadotropin responses to gonadotropin releasing hormone were significantly greater than these levels and responses in age-matched controls. Although the percentage of free testosterone was lower than control values in the hyperthyroid men, calculated levels of free testosterone were not different from normal. Lower than normal percentages of free estradiol values resulted in higher than normal calculated free estradiol levels. As a result, the free testosterone/free estradiol ratio in the men with Graves' disease was lower than normal. Although mean sperm densities in the hyperthyroid men were not different from control values, the percent forward progressive motility of sperm from these men was significantly lower than control values. The hormonal and seminal abnormalities corrected when the patients became euthyroid after radioiodine therapy. The results of this study indicate that hyperthyroid men may have abnormalities in their hypothalamic-pituitary-testicular axes.
Adolescent↗