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S J Samuels

Publications and source records attributed to S J Samuels.

At least 37 records · Page 2Linked to original sources
PubMed1995

A cross-sectional survey of respiratory and general health outcomes among semiconductor industry workers.

As part of the Semiconductor Health Study, we performed a cross-sectional survey to assess prevalence of specific nonreproductive health outcomes and their association with occupational exposures. A total of 3,175 persons from eight manufacturing sites across the U.S. completed a health and work questionnaire (78% participation rate). After adjusting for confounders, responses from fabrication room (fab) workers indicated a greater risk than those of nonfab workers for upper respiratory symptoms (relative risk [RR] = 1.08; 95% confidence interval [CI] = 1.03-1.13); a dose-response effect with hours per day spent in fabs was observed. Fab workers also had greater prevalence for persistent wheezing (RR = 1.82; 95% CI = 1.15-2.87), dermatitis within the past year (RR = 1.19; 95% CI = 1.04-1.35), and alopecia (RR = 1.73; 95% CI = 1.16-2.54). Female sex, a somatization index score, and smoking were important nonoccupational covariates. Increased respiratory symptoms may result from occupational exposures in fabs; further research is needed to identify causal agents and develop prevention strategies.

Adult↗
PubMed1995

A cross-sectional study of musculoskeletal symptoms and risk factors in semiconductor workers.

As part of the cross-sectional component of the Semiconductor Health Study, we assessed prevalence of specific musculoskeletal symptoms and their association with possible ergonomic risk factors. A total of 3,175 persons (78% participation rate) from eight manufacturing sites across the U.S. completed a health and work questionnaire. Using logistic regression methods to adjust for nonoccupational factors, we compared musculoskeletal symptom (self report) prevalence among fabrication room (fab) and nonfab workers, among specific work process groups, and among workers exposed to selected ergonomic stressors. Overall, seven of 12 musculoskeletal outcomes were significantly more prevalent among fab workers. Distal upper-extremity symptoms were more common among fab than nonfab workers [relative risk (RR) = 1.44, 95% confidence interval (CI) = 1.26-1.63] and showed a dose-response effect with hours per day spent in the fab; increased risk was associated with frequency of lifting and with use of vacuum wands and projection aligners. Female sex and high somatization index score were associated with increased reporting for all musculoskeletal outcomes.

Adult↗
PubMed1995

Fertility history of currently employed male semiconductor workers.

Fertility among men working in semiconductor manufacturing during 1984-89 was assessed in a 1990-91 cross-sectional study of eight companies. Men working in wafer fabrication rooms (fabs) (n = 241, 165 births) were compared to men in nonfabrication (nonfab) jobs (n = 447, 300 births). Results showed that 17% of fab men and 14% of nonfab men reported ever trying for > or = 1 year to conceive [relative risk (RR) = 1.21, 95% confidence interval (CI) = 0.83-1.74]. Crude birth rates (births/1,000 person months) were similar [15 fab, 17 nonfab; crude fertility ratio (FR) = 1.09, 95% CI = 0.86-1.36], as were birth rates adjusted by Cox models for confounders (adjusted FR = 0.98, 95% CI = 0.80-1.19, p = 0.79). Fab men who worked in furnace, thin-film, or ion implantation areas were more likely than nonfab men to report previous difficulty conceiving (25%, RR = 1.79, 95% CI = 1.09-2.94), and their past fertility was lower (nine births/1,000 person months; crude FR = 0.66, 95% CI = 0.40-1.02; adjusted FR = 0.73, 95% CI = 0.50-1.09, p = 0.12). Problems included lack of contraception data and misclassification of fab subgroups.

Cross-Sectional Studies↗
PubMed1994

Megestrol acetate in patients with AIDS and cachexia.

OBJECTIVE: To study the effects of a megestrol acetate liquid formulation (800 mg/d) on body weight, body composition, caloric intake, and mental outlook in patients with the acquired immunodeficiency syndrome (AIDS) who had cachexia. DESIGN: Twelve-week, multicenter, randomized, double-blind, placebo-controlled trial. SETTING: Multiple clinical centers. PATIENTS: 100 patients with AIDS who had weight loss of 10% or more of ideal body weight were randomly assigned to placebo (n = 48) or megestrol acetate (n = 52). MEASUREMENTS: Caloric intake, body weight, body composition, and sense of well-being. RESULTS: Most patients receiving megestrol acetate had increased caloric intake resulting in body weight gain (mainly fat mass). From baseline to week 8, the megestrol acetate group increased their daily caloric intake by 608 calories, whereas the placebo group increased intake by 134 calories (difference, 474 calories; 95% CI, -68 to 880 calories). Body weight in the megestrol acetate group increased by 3.86 kg from baseline to week 8, although it decreased by 0.46 kg in the placebo group (difference, 4.32 kg; CI, 2.42 to 6.22 kg). At week 8 in the megestrol acetate group, patients gained 3.68 kg in fat mass and those in the placebo group lost 0.28 kg (difference, 3.96 kg; CI, 2.49 to 5.43 kg). Body water, lean mass, and patient survival were not statistically different between treatment groups. Patients treated with megestrol acetate had an increased sense of well-being when compared with patients who received placebo. CONCLUSIONS: This megestrol acetate liquid formulation is well tolerated, increases food intake, results in body weight gain, and improves the sense of well-being in cachectic patients with AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Bone sarcoma characteristics and distribution in beagles injected with radium-226.

A total of 155 primary bone sarcomas were found in 131 of the 246 beagles injected with 226Ra and 5 primary bone sarcomas were found in 4 of the 158 unexposed controls. Of these 155 bone sarcomas, 146 (94%) were osteosarcomas and 9 were non-osteosarcomas. An additional 31 primary bone sarcomas (28 osteosarcomas) developed in 44 dogs terminated from the main study because of limb amputation for bone sarcoma. Non-osteosarcomas predominated in both the controls and the second lowest of six logarithmically increasing dose levels (there were no bone sarcomas in the lowest dose group). Osteosarcomas predominated at the higher dose levels, and incidence tended to increase as dose increased. The 146 osteosarcomas were distributed quite evenly between males and females (72:74). Of the 9 non-osteosarcomas, 6 occurred in males and 3 in females. The ratio of bone sarcomas of the appendicular skeleton to those in the axial skeleton was 110:45, with osteosarcomas occurring more often in the appendicular skeleton (108:38). Cases of multiple primary bone sarcomas in dogs injected with 226Ra were found only in the four highest dose groups. Amputations were performed on 44 of the 96 dogs (94 injected and 2 unexposed) that developed appendicular bone sarcomas. A statistical study of the distribution of bone sarcomas among 16 separate bone groups showed a statistically significant correlation to cancellous skeletal surface, but the variability among bone groups was too large for this relationship to be of real predictive value. It is postulated that the distribution of bone sarcomas reflects primarily the relative cell division rates in the bone groups and secondarily the radiation dose distribution, with the highest occurrence of bone sarcoma in the humeri, pelvis, femora and tibiae/fibular tarsal, and no occurrence in the coccygeal vertebrae, sternum, forepaws or hindpaws.

Animals↗
PubMed1993

Bone sarcoma characteristics and distribution in beagles fed strontium-90.

A total of 66 primary bone sarcomas were diagnosed in 47 beagles; 43 of these dogs were part of the 403 beagles fed 90Sr and 4 were part of the 162 controls. Multiple primary bone sarcomas were found in 15 of the 47 beagles (32%). The incidence of multiple primary bone sarcoma was restricted to the two highest dose groups, except for a single control dog which developed two bone sarcomas. A threshold-like radiation dose response was observed; no sarcomas were observed in the lowest three dose groups, but the number of primary bone sarcomas increased rapidly in the higher dose groups. Of the 66 primary sarcomas, 49 were osteosarcomas (74%). As the dose increased, the proportion of osteosarcomas increased sharply, 4/10 (40%), 26/29 (90%), and 16/18 (89%), in the three highest dose groups. Thirteen of the bone sarcomas of other types occurred in males, and 4 in females, whereas 21 osteosarcomas occurred in males, and 28 in females. The ratio of bone sarcomas of the appendicular skeleton to those in the axial skeleton was 40:26, with osteosarcomas occurring more often in the appendicular than the axial skeleton (32:17), whereas nonosteogenic tumors showed no predilection (8:9). A statistical study of the distribution of bone sarcomas among 16 separate bone groups showed a correlation only with the distribution of cancellous bone volume-to-surface ratio and not with either skeletal mass distribution or dose distribution. The highest occurrence of sarcomas was in the humeri, femora, and mandible, and no occurrence in the coccygeal vertebrae, paws, or sternum. It is postulated that the distribution of bone sarcomas reflects a critical combination of the osteosarcoma precursor cell population, their cell division rate, and the radiation dose absorbed by these cells.

Animals↗
PubMed1992

Urinary mutagenic activity in workers exposed to diesel exhaust.

We measured postshift urinary mutagenicity (mutu; n = 306 samples) on a population of railroad workers (n = 87) with a range of diesel exhaust exposures. Postshift urinary mutagenicity was determined by a sensitive microsuspension procedure using Salmonella strain TA98 +/- S9. Number of cigarettes smoked on the study day and urinary cotinine were highly correlated with postshift urinary mutagenicity. Diesel exhaust exposure was measured over the work shift by constant-flow personal sampling pumps. Respirable particle concentrations were adjusted for the contribution of environmental tobacco smoke, as estimated from nicotine concentration on treated filters. The relative ranking of jobs by this adjusted respirable particle concentration (ARP) was correlated with relative contact the job groups have with operating diesel locomotives. After adjustment for cigarette smoking (active and passive) in multiple regressions, there was no independent association of diesel exhaust exposure, as estimated by ARP, with postshift urinary mutagenicity among smokers or nonsmokers. An important finding is the detection of "baseline" mutagenicity in most of the nonsmoking workers. Despite the use of individual measurements of diesel exhaust exposure, the absence of a significant association in this study may be due to the low levels of diesel exposure, the lack of a specific marker for diesel exhaust exposure, and/or urinary mutagenicity levels from diesel exposure below the limit of sensitivity for the mutagenicity assay.

Adult↗
PubMed1992

Epidemiology of dermatitis among California farm workers.

To estimate the prevalence of dermatitis and risk factors for skin disease in California farm workers, a cross-sectional survey was conducted among grape, citrus, and tomato workers. The prevalence of contact dermatitis was 2% and lichenified hand dermatitis was 13%. Grape workers were more likely to report rashes in the last 12 months than were tomato workers or citrus workers. Grape workers were more likely to have contact dermatitis and lichenified hand dermatitis than were citrus or tomato workers. Increasing hours per week in agriculture, male sex, and not wearing gloves were associated with more lichenified hand dermatitis. We conclude that skin disease in agricultural workers may be causally associated with crop-specific exposures and lack of protective equipment.

Adult↗
PubMed1992

Reduced FVC among California grape workers.

Pulmonary disease due to organic and inorganic dust inhalation represents a significant health problem in the agricultural community. In response to concern over the potential adverse health effects of agricultural exposures, and to address the question of whether the specific crop worked was associated with decreased lung function, we conducted a cross-sectional survey of pulmonary function in a population of 238 grape workers, 355 tomato workers, and 166 citrus workers in California's Central Valley. In addition, 92 workers (66 males and 26 females) performed spirometry before and after an 8-h work shift. Multiple regression analysis of pulmonary function in all 759 workers revealed that age, height, and smoking-adjusted mean preshift FVC was lower in grape workers than in citrus workers in each of three sex and age groups studied: decreased 314 ml for males greater than or equal to 25 yr of age p less than 0.05, 82 ml for males less than 25 yr, and 83 ml for females greater than or equal to 20 yr. Mean adjusted preshift FVC was also lower in grape workers than tomato workers (decreased 249 ml in males greater than or equal to 25 yr [p less than 0.05], 51 ml for males less than 25 yr, and 46 ml for females greater than or equal to 20 yr). Adjusted mean FEV1 was not different by crop, but FEV1/FVC and forced-expiratory flow from 25 to 75% of the FVC (FEF25-75) were significantly elevated in grape workers of the three age and sex groups compared with citrus or tomato workers.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Smoking, respiratory symptoms, and pulmonary function among a population of Hispanic farmworkers.

We conducted a cross-sectional study in the agricultural Central Valley to evaluate the prevalence of respiratory symptoms, smoking status, and pulmonary function in Hispanic California farmworkers. Of 759 farmworkers completing questionnaires and spirometry, 747 were Hispanic. The prevalences of current, former, and never smokers (29, 17, and 54 percent, respectively) were comparable to rates in other studies of Hispanics, but daily cigarette consumption (median-five for men and three for women) was lower than in comparison populations. Prevalences of chronic cough, chronic phlegm, and persistent wheeze were low (1.6, 5.1, and 2.8 percent, respectively). Current smoking, increased age, female sex, and working greater than or equal to 8 months per year in agriculture were associated with increased prevalence of respiratory symptoms. Adjusted lung function was higher than for reference populations. Hispanic California farmworkers have a similar smoking prevalence to other Hispanic populations, but lower respiratory symptom prevalences and higher pulmonary function are consistent with lower daily cigarette consumption and the "healthy worker effect."

Adolescent↗
PubMed1992

Creatine kinase and its MB isoenzyme in the third trimester and the peripartum period.

Forty-nine normal pregnant women were recruited late in the third trimester for serial determinations of creatine kinase (CK) and its MB isoenzyme fraction (CK-MB) at four different times: (1) on recruitment between 36 and 40 weeks' gestation, (2) on admission in active labor, (3) immediately after delivery, and (4) on the first postpartum day. In the patients with vaginal delivery (n = 43) total CK was significantly elevated at time 4 compared with times 1, 2 and 3 (P value < .0001). CK-MB fraction was also significantly elevated at time 4 compared with times 1, 2 and 3 (P value < .0001). In 35.7% of the patients at time 4, CK-MB was sufficiently elevated to give the laboratory interpretation of "borderline" or "consistent with a myocardial infarction," even though none of the patients had cardiac symptoms or complications. A review of the literature shows that CK-MB is found not only in myocardium but also in uterus and placenta. The implication of this study is that elevations in total CK and CK-MB should be used with caution during the peripartum period to diagnose myocardial ischemia or infarction.

Adult↗
PubMed1992

Prospective assessment of early fetal loss using an immunoenzymometric screening assay for detection of urinary human chorionic gonadotropin.

OBJECTIVE: To develop an economical, nonradiometric immunoenzymometric assay (IEMA) for the detection of urinary human chorionic gonadotropin (hCG) in studies of early fetal loss. To be effective, the IEMA must have a sensitivity equal to the standard immunoradiometric assay (IRMA) and sufficient specificity to eliminate the need for screening most nonconceptive cycles with the expensive and labor-intensive IRMA. DESIGN: Two different assays were used to measure hCG in daily early morning urine samples from potential conceptive cycles. SETTING: Women undergoing donor artificial insemination (AI) were evaluated in a prospective study. PATIENTS, PARTICIPANTS: Ninety-two women volunteers were selected on the basis of apparent normal reproductive health. INTERVENTIONS: Artificial insemination with nonfrozen donor semen was performed by cervical cup twice each menstrual cycle at 48-hour intervals, and daily urine samples were self-collected throughout the menstrual cycle. MAIN OUTCOME MEASURES: An IEMA was developed to detect urinary hCG using the same antibodies as in the standard IRMA; a study was designed to determine whether this nonradiometric assay could successfully detect the early fetal loss that was detected by the IRMA. RESULTS: Of 224 menstrual cycles analyzed by both assays, a total of six early fetal losses were detected by the IRMA. When the tentative screening rule was set to allow all six of these losses and 95% of future losses to be detected by the IEMA, an additional 34 false-positive results were detected by the IEMA. The specificity of the IEMA with this rule was calculated to be 84%. CONCLUSION: An IEMA based on the same antibodies used for the standard IRMA can serve as an efficient screening assay for the detection of early fetal loss. When the IEMA is used in this manner, nearly 80% of screened menstrual cycles can be eliminated without further testing by the IRMA.

Abortion, Spontaneous↗
PubMed1991

Power and detectable risk of seven tests for standardized mortality ratios.

Power and minimum detectable risk are calculated for seven one-sided tests of standardized mortality ratios with Poisson-distributed events. Each test contrasts the number of observed deaths (D) with the number expected (E). Three tests use exact Poisson probabilities: 1) the exact test, which computes a p value as the probability of equaling or exceeding the number of observed events; 2) the optimal randomized exact test which, although not used in practice, serves as a standard for the other statistics; and 3) the exact "mid-p" procedure, which counts only one-half the probability of the observed event. The remaining four tests use normal approximations to the Poisson ("Z statistics"): 4) Z = magnitude of D-E/square root of E; 5) the Z statistic corrected for continuity, Z = (magnitude of D-E)-0.5)/square root of E; 6) a statistic based on a square root transformation, Z = 2(square root of D-square root of E); and 7) a statistic created by Byar, which, when D is greater than E, is Z = square root of 9D[1-1/(9D)-3 square root of D/E]. Power differences among these procedures with one-sided alpha of 0.05, 0.025, and 0.01 are small as long as four or more events are expected. If fewer than four events are expected, the uncorrected Z has unacceptably high type I error. Simple approximations to the power and detectable risk of these tests are evaluated and prove satisfactory. Differences in minimum detectable risk, actual and approximated, are slight for E of 2.0 or more.

Humans↗
PubMed1991

Semen quality in varicocele patients is characterized by tapered sperm cells.

We used a retrospective case-control study design to compare sperm morphology in 50 varicocele patients and 50 patients with idiopathic infertility. Cases and controls were matched for the percentage of motile sperm and total sperm number per ejaculate. Varicocele patients had significantly more tapered sperm (36% +/- 3% versus 15% +/- 2%) and significantly fewer oval sperm (41% +/- 3% versus 47% +/- 2%). There was no significant difference between cases and controls in any other morphological type.

Case-Control Studies↗
PubMed1991

Design and methods for a survey of lead usage and exposure monitoring in California industry.

A probability sample of California workplaces in 1986 estimated the numbers of workers using lead and their coverage by biological and environmental monitoring. Study steps included (1) identifying 505 stand ard industrial classifications (SICs) with possible lead use; (2) creating an employer lis; (3) identifying for oversampling seven single SICs and a group of 165 SICs with documented high ambient air lead; (4) further stratification by workforce size; (5) prediction from National Institute for Occupational Safety and Health surveys the number of lead-using workers for each employer; (6) drawing facilities into the sample with selection probability proportional to the number of workers predicted to use lead; (7) adjusting the sample selection if an employer listing covered multiple facilities; (8) sending a first-stage telephone/mail questionnaire to identify lead users, who were sent a second questionnaire; (10)follow-up which, aided by statutory authority, resulted in completion rates over 90%; (11) ranking lead-using processes by intensity of exposure; and (12) analysis. Sources of error include random sampling error, misleadingly large standard errors because sampling was with replacement, gaps in the employer list, and inaccurate responses. As a measure for the probability proportional to size sampling, total work force count would have been superior to the predicted number of lead users. Restriction to a single hazard makes a questionnaire-based study feasible, but names of workers, rather than counts, should be requested and a subsample should be visited.

California↗
PubMed1991

Lead use in California industry: its prevalence and health implications.

An estimated 230,000 workers were reported to work in lead-using activities as a result of a 1986 statistical survey of employers in California. However, 68% of these workers worked in activities of relatively low hazard. This included 114,000 workers engaged in electronic soldering. Over 1800 workers were reported to work in battery manufacture, a relatively high-hazard activity, but with consistent monitoring and protection. In contrast, over 4300 workers were involved in radiator repair activities, a high-hazard activity with inconsistent monitoring and protection. Over 8% of construction workers were reported to work in lead-using processes. This sector is exempt from federal Occupational Safety and Health Administration (Fed/OSHA) and California Occupational Safety and Health (Cal/OSHA) lead standards, yet some of the most hazardous activities (welding, grinding, and cutting, etc.) occurred here. Comparison of projections from the National Occupational Hazard Survey of potential lead exposure in California with these survey results suggests consistent and reliable assessment of the major sources of potential occupational exposure to lead.

California↗
PubMed1991

Post-partum anovulation in nursing mothers.

An analysis of breastfeeding and ovulation data from 72 nursing mothers is presented. A proportional hazards model of the data strengthens the hypothesis that a pattern of short, frequent bouts of nursing defines a risk-set of women less susceptible to post-partum ovulation than those who choose to nurse on a schedule of relatively lengthy and infrequent bouts. In contrast, no effect of maternal weight-for-height on the month-specific rate of post-partum ovulation could be detected in the study population comprised of American mothers trained in self-observation of fertility signs.

Anovulation↗