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Biomedical subjects

S J Samuels

Publications and source records attributed to S J Samuels.

At least 73 records · Page 4Linked to original sources
PubMed1987

Antisperm antibodies bind with different patterns to sperm of different men.

Immunologic infertility is an important area of current clinical research. The immunobead test is a laboratory method that identifies the classes of antisperm antibodies and their binding sites on the sperm surface. In this study we have investigated the variability in the pattern of antibody binding to spermatozoa after passive transfer from blood serum. Serum from a single donor containing antisperm antibodies of the IgG class was used in all experiments. The spermatozoa from 27 semen donors were found to differ significantly in the degree and location of immunobead binding after exposure to this serum. There was substantial day-to-day variability in the results for individual semen donors and the overall variability in test results was significantly greater when a number of semen donors was used rather than a single donor. These data suggest that details of antisperm antibody binding after passive transfer from body fluids may depend on the sperm donor. The design of research studies involving antibody transfer must take this source of variability into account.

Adult↗
PubMed1987

Comparison of serum estradiol to urinary estrone conjugates in the rhesus macaque (Macaca mulatta).

Paired urine and serum samples were collected daily during fourteen nonconceptive (7 females) and ten conceptive (9 females) ovarian cycles from a total of 12 female rhesus monkeys (Macaca mulatta). Daily urine samples were analyzed for concentrations of estrone conjugates (Ei Conj). Serum samples were evaluated for concentrations of estradiol (E2) and progesterone (P) by radioimmunoassay (RIA), and bioactive luteinizing hormone (bLH) and monkey chorionic gonadotropin (mCG) were analyzed by a mouse Leydig cell bioassay. Linear correlation (r) between urinary E1 Conj and serum E2 (r range = -0.176-0.948) during nonconceptive cycles aligned by the preovulatory E1 Conj peak (Day 0) improved when daily hormone values were realigned to account for an approximately 24-h delay in the excretion of hormonal metabolites in urine (r range = 0.465-0.967). Similarly, correlation between urinary E1 Conj and serum E2 during conceptive cycles aligned by Day 0 (r range = 0.300-0.824) improved when values were offset by 24 h (r range = 0.408-0.876). When conceptive cycles were compared to nonconceptive cycles, serum P levels were significantly elevated over nonconceptive levels by Day +12 (p less than 0.001), and urinary E1 Conj levels by Day +13 (p less than 0.02), whereas serum E2 and bLH were both significantly elevated by Day +14 (p less than 0.0006 and p less than 0.01, respectively). In both nonconceptive and conceptive cycles, urinary E1 Conj paralleled serum E2 and demonstrated incremental increases above baseline levels, which were greater than for serum E2.

Animals↗
PubMed1985

Results of treatment in patients with end-stage renal disease: a multivariate analysis of risk factors and survival in 341 successive patients.

Factors that affect survival in patients with end-stage renal disease (ESRD) are still only partially understood. We report an analysis on a cohort of 341 successive patients who started ESRD treatment in one institution. Survival was calculated from the start of ESRD treatment, whether initial treatment was by dialysis (335 patients) or transplantation (6 patients). Analysis of factors affecting survival was done using the Cox multivariate hazard analysis. Relative risks were calculated for several demographic factors, the primary renal disease, the presence or absence of various high-risk co-morbid factors, and for a first transplant from a living-related or cadaver donor. Older patients, patients with no prior health insurance, those with diabetic nephropathy, and those with small kidneys of unknown cause had statistically significantly higher risks of dying. The risk of dying decreased by year of start of ESRD treatment. Living related donor transplantation was associated with a decreased hazard to age 45 years and older; whereas cadaver donor transplantation was associated with a hazard that increased with age and was significantly increased by age 45.

Actuarial Analysis↗
PubMed1985

Statistical methods for describing occupational exposure measurements.

An important step in studies relating worker health to industrial exposure is the estimation of mean exposure levels. The investigator frequently has to rely on industrial hygiene measurements collected for other purposes. Samples may have been taken at several companies on different dates, and on each occasion multiple individual samplers may have been employed. Often it is not recognized that readings from such a hierarchical arrangement are correlated; for example, samples taken at the same time and location are more alike than samples taken on different days. This correlation invalidates the commonly used standard errors of sample means and the usual sample standard deviation. A component of variance analysis is suggested which quantifies within-day, between-day and between-company variation. Estimators of mean exposure are presented with correct standard errors. The techniques are illustrated by a small set of data and by a recent study of exposures to styrene in 36 companies manufacturing reinforced plastics.

Environmental Exposure↗
PubMed1985

Occupational styrene exposure for twelve product categories in the reinforced-plastics industry.

Approximately 1500 occupational styrene exposure values from 28 reinforced-plastic manufacturers were collected retrospectively from companies and state and federal agencies. This report describes the major types of manufacturing processes within the reinforced-plastics industry and reports on the availability, collection and analysis of historical exposure information. Average exposure to styrene in most open-mold companies (24-82 ppm) was generally 2-3 times the exposure in press-mold companies (11-26 ppm). Manufacturers of smaller boats had mean styrene exposures of 82 ppm as compared to 37 ppm for yacht companies. There was considerable overlap in styrene exposure among job titles classified as directly exposed within open- and press-mold processing.

Chemical Industry↗
PubMed1985

Reproductive outcomes in women exposed to solvents in 36 reinforced plastics companies. I. Menstrual dysfunction.

Recent studies have suggested that exposure to styrene monomer and other solvents is associated with menstrual disturbances. This is the first U.S. study to evaluate the effects of exposure to styrene on dysmenorrhea, intermenstrual bleeding, secondary amenorrhea, menstrual blood clots, and hypermenorrhea. A comprehensive questionnaire was administered to 1,535 blue-collar workers. Multiple logistic regression analyses did not reveal a positive association between styrene exposure and any menstrual abnormality. Risk factors associated with menstrual disturbances included chronic illness with secondary amenorrhea (p less than or equal to .005), nulliparity with both decreased blood clots (p less than or equal to .005) and hypermenorrhea (p less than or equal to .001), smoking with blood clots (p less than or equal to .005), and age with hypermenorrhea (p less than or equal to .001). The overall prevalences of menstrual disorders were 14% for dysmenorrhea, 16% for intermenstrual bleeding, 7% for secondary amenorrhea, 40% for menstrual blood clots, and 31% for hypermenorrhea.

Adult↗
PubMed1980

Intrafamilial associations of cholesterol and triglyceride among related and unrelated household members.

The purpose of this report was to assess intrafamilial associations of lipids between related and unrelated household members seen in the course of a population-based survey of lipids in schoolchildren and their parents. Fasting plasma total cholesterol and triglyceride levels were measured in 6,857 and 3,079 adults. Age effects were removed for each sex-race group using a third-degree polynomial regression of lipid on age; the residuals were then used as observations in the analyses. For both cholesterol and triglyceride, significant positive correlations existed between father and son, father and daughter, mother and son, and mother and daughter. For both cholesterol and triglyceride, although the mother-child correlations were stronger than those for father-child, they were not significantly different. There were no significant correlations between step, foster, or adoptive parents and children. For cholesterol in sibships of size two, intrasibship correlations for fully related siblings were 0.333, for half-sibs 0.164, and for unrelated sibs, 0.085. Consistently closer intrafamilial cholesterol and triglyceride associations between related than unrelated family members, and the strong parental effects on cholesterol and triglyceride indicate, in aggregate, that a considerable proportion of the variation of cholesterol and triglyceride can be explained by genetic factors.

Adult↗
PubMed1976

Comparison of nonretarded and mentally retarded children on a perceptual learning task.

The performances of 12 EMR and 12 nonretarded sixth-grade children on a perceptual learning task were compared to investigate the information processing of visually presented stimuli in individuals with different intelligence levels. A minicomputer flashed either familiar (lowercase) or unfamiliar letters (Gibson-like figures) in either a stimultaneous or successive mode on a same-different matching task. The computer automatically calculated accuracy and latency data for each subject. Results showed that accuracy was superior in the nonretarded group and that mean latencies for the EMR group was consistently higher than those of the nonretarded group. However, when latencies were corrected for differences in basic reaction time, there were no significant differences between the groups in the speed of processing the information.

Attention↗