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Biomedical subjects

S Samuels

Publications and source records attributed to S Samuels.

At least 19 recordsLinked to original sources
PubMed1992

Seroepidemiology of viral infections among intravenous drug users in northern California.

Intravenous drug users are frequently exposed to parenterally transmitted viral infections, and these infections can spread to the general population through sexual activity. We investigated the prevalence of serologic markers for human immunodeficiency virus type 1 (HIV-1), human T-cell lymphotropic virus type I/II (HTLV-I/II), hepatitis B virus (HBV), and hepatitis C virus (HCV) in intravenous drug users and their sexual contacts. Of 585 drug users from northern California tested for these serologic markers, 72% were reactive for the antibody to HCV, 71% for the antibody to hepatitis B core antigen, 12% for HTLV-I/II antibodies, and 1% for the HIV-1 antibody. The prevalence of serologic markers for these four viruses correlated with the duration of intravenous drug use, the ethnic group, and the drug of choice. More than 85% of subjects infected with either HCV or HBV were coinfected with the other virus. All persons reactive to HTLV-I/II antibodies had antibodies for either HBV or HCV. Of 81 sexual contacts tested, 17% had evidence of HBV infection while only 6% were reactive for HTLV-I/II antibodies and 4% for the antibody to HCV. None of this group was infected with HIV-1. We conclude that HTLV-I/II and HCV are inefficiently transmitted to sexual contacts while HBV is spread more readily. Programs designed to discourage the sharing of drug paraphernalia, such as needle and syringe exchanges, should decrease the risk of parenterally spread viral infections in intravenous drug users and thus slow the spread of these infections to the general population.

Adult↗
PubMed1991

Net patient revenues lag behind increases in expenses.

Total net patient revenues for the nation's hospitals lagged behind increases in expenses during the first nine months of 1990, according to data from the American Hospital Association's National Hospital Panel Survey. And hospitals in some regions, particularly in the Northeast, saw more troubling performance than others. Meanwhile, the number of inpatient days dropped 1.1 percent during the same period.

Data Collection↗
PubMed1991

The impact of hospital closures on travel time to hospitals.

In this paper, we investigate the impact of closures on local access to hospital care. We measured the incremental travel time to alternate hospitals. The results show that even in rural markets, closures nearly always occur near open hospitals, which by itself may imply a minimal effect in terms of human welfare. These results support the view that hospital closures rarely directly limit general access to hospital care.

Health Facility Closure↗
PubMed1990

Environmental and biological monitoring for lead exposure in California workplaces.

Patterns of environmental and biological monitoring for lead exposure were surveyed in lead-using industries in California. Employer self-reporting indicates a large proportion of potentially lead-exposed workers have never participated in a monitoring program. Only 2.6 percent of facilities have done environmental monitoring for lead, and only 1.4 percent have routine biological monitoring programs. Monitoring practices vary by size of facility, with higher proportions in industries in which larger facilities predominate. Almost 80 percent of battery manufacturing employees work in job classifications which have been monitored, versus only 1 percent of radiator-repair workers. These findings suggest that laboratory-based surveillance for occupational lead poisoning may seriously underestimate the true number of lead poisoned workers and raise serious questions regarding compliance with key elements of the OSHA Lead Standard.

California↗
PubMed1989

Prevalence of hazardous exposures in veterinary practice.

All female graduates of a major U.S. veterinary school were surveyed by mailed questionnaire to obtain details of work practice and hazard exposure during the most recent year worked and during all pregnancies. Exposure questions were based on previously implicated occupational hazards which included anesthetic gases, radiation, zoonoses, prostaglandins, vaccines, physical trauma, and pesticides. The response rate was 86% (462/537). We found that practice type and pregnancy status were major determinants of hazard exposure within the veterinary profession. Small-animal practitioners reported the highest rates of exposure to anesthetic gas (94%), X-ray (90%), and pesticides (57%). Large-animal practitioners reported greater rates of trauma (64%) and potential exposure to prostaglandins (92%), Brucella abortus vaccine (23%), and carbon monoxide (18%). Potentially hazardous workplace practices or equipment were common. Forty-one percent of respondents who reported taking X-rays did not wear film badges, and 76% reported physically restraining animals for X-ray procedures. Twenty-seven percent of the respondents exposed to anesthetic gases worked at facilities which did not have waste anesthetic gas scavenging systems. Women who worked as veterinarians during a pregnancy attempted to reduce exposures to X-rays, insecticides, and other potentially hazardous exposures. Some potentially hazardous workplace exposures are common in veterinary practice, and measures to educate workers and to reduce these exposures should not await demonstration of adverse health effects.

Anesthetics↗
PubMed1989

Assessing dermatitis in epidemiologic studies: occupational skin disease among California grape and tomato harvesters.

We conducted a cross-sectional investigation to determine whether table grape harvesters, who have significant cutaneous contact with crop-associated materials that may cause skin disease, are more likely to develop dermatitis than are a control group of tomato workers performing mechanical harvesting with minimal cutaneous contact with crop-associated substances. A secondary aim was to develop methods for studying skin disease in farm workers, including a standard questionnaire and physical examination. California table grape workers (n = 183) and tomato workers (n = 43) completed an interviewer-administered questionnaire and waist-up physical examination at their work site during harvest operations. On physical examination, pustular eruptions such as acne and folliculitis were present in 30% of subjects, and eczematous rashes were noted in 10% of subjects. Irritant or allergic contact dermatitis was diagnosed in 2% of subjects. No significant differences in prevalence for these skin conditions were observed between the two groups of workers. In contrast to the physical examination results, grape workers were more likely than tomato workers to report a rash occurring in the previous 3 months (52% vs. 19%, p less than 0.001). Explanations for this discrepancy are discussed. The sensitivity of the questionnaire for current skin conditions was 31%, and the specificity was 94%. Improved sensitivity was seen for eczematous skin conditions (55%). We conclude that questionnaires provide an efficient means of assessing subject characteristics, but may have limited sensitivity for some dermatologic outcomes.

Agricultural Workers' Diseases↗
PubMed1989

Herpes labialis treatment with acyclovir 5% modified aqueous cream: a double-blind randomized trial.

The efficacy of 5% acyclovir in a modified aqueous cream vehicle (ACV-MAC) in the treatment of recurrent herpes labialis was tested in a randomized, double-blind clinical trial with the modified aqueous cream vehicle as a control medication. The ACV-MAC formulation has previously been shown to offer superior cutaneous absorption relative to other topical acyclovir formulations. Treatment was initiated by patients within 1 hour of prodrome in an attempt to maximize clinical impact of this virustatic drug. While the patient group receiving active drug showed a trend toward accelerated healing, no significant differences for lesion or healing characteristics could be measured between the two treatment groups. It is suggested that optimal efficacy of ACV-MAC may be predicated on prophylactic treatment, that is, "trigger"-initiated rather than prodrome-initiated treatment.

Acyclovir↗
PubMed1987

A behavioral evaluation of pest control workers with short-term, low-level exposure to the organophosphate diazinon.

Neurobehavioral effects of short-term, low-level exposure to diazinon were investigated among 99 pest control workers tested before and after their work shift with a computer-assisted neurobehavioral test battery. Each subject completed a brief neurological screening examination, a symptom questionnaire, and tests of concentration, eye-hand coordination, pattern recognition, visual memory, and finger tapping. The diazinon metabolite diethylthiophosphate (DETP) was measured in pre- and post-shift urine samples collected from 46 diazinon applicators applying granulated diazinon onto residential properties with lawn spreaders, and 56 non-applicators. Post-shift median DETP for applicators and non-applicators was 24 and 3 ppb, respectively. Full shift, whole body exposure to diazinon was quantitated for 19 subjects using personal air monitoring and passive badges. Median diazinon exposure for applicators and non-applicators was 2.1 and 0.03 mg, respectively. Mean duration of pesticide application was 39 days (SD = 12 days) before testing. No adverse DETP-related changes in pre- or post-shift neurobehavioral function were found with multiple linear regression models after adjusting for age, sex, education, and ethanol intake, although Symbol-Digit pairing speed was slower among the applicators as a group. The prevalence of 18 symptoms possibly related to diazinon exposure was not elevated among applicators. The study failed to demonstrate diverse behavioral effects of short-term, low-level diazinon exposure in a pest control program which emphasized personal protective equipment and direct supervision.

Adult↗
PubMed1987

Amniocentesis before 15 weeks' gestation: outcome, risks, and technical problems.

Between January 1, 1979, and May 30, 1986, 4750 amniocenteses were performed by a single physician at the University of California, Davis, Medical Center. Of these procedures 541 (11.4%) were considered early amniocenteses (performed before the fifteenth week since last menstrual period). The medical records were reviewed for maternal age, amniocentesis indication, ultrasound findings, location of the placenta, location of the needle insertion (transplacental versus nontransplacental), color of the amniotic fluid, results of prenatal testing, complications of procedure, and pregnancy outcome. Complete follow-up data were possible for 308 subjects and obtained for 298 (96.8%). There were 11 miscarriages (3.6%), two stillbirths (0.7%), and one neonatal death (0.3%), resulting in a total postprocedural loss rate of 4.7% (14/298). If those patients with a preamniocentesis history of bleeding are eliminated, the total postprocedural rate of loss is 3.3% (7/211). Miscarriage within 2 weeks of amniocentesis occurred in 1.7% of procedures (5/298). No significant difference in pregnancy outcome was noted between transplacental and nontransplacental amniocentesis.

Abortion, Spontaneous↗
PubMed1986

Pre-natal amino acid transport inhibition: long term influences on behavior and protein metabolism.

DBA/2J mice were exposed in utero, between days 15-18 of gestation, to either of two enzyme inhibitors, previously shown to decrease blood-brain, large-neutral amino acid transport in adults: L-methionine-RS-sulfoximine and 2-imidazolidone-4-carboxylic acid. The young mice demonstrated persistently altered motor behavior relative to saline controls when 40-42 days old and evidence of differences in the entry and incorporation of 14C-valine in brain at up to 80 days of age. The findings suggest that interference with blood-brain amino acid transport in utero has long term consequences. This may be related to some human conditions such as maternal phenylketonuria.

Amino Acids↗
PubMed1986

Sperm binding activity of the zona pellucida of immature mouse oocytes.

Immature oocytes taken from ovarian follicles are sometimes used in studies of sperm-zona interaction in species for which it is difficult to obtain ovulated eggs. As yet, however, there has been no quantitative comparison of the sperm binding capacities of immature and ovulated oocytes. We report here that in mice there is no significant difference in the numbers of sperm which bind to the zonae pellucidae of immature and ovulated oocytes in vitro. These results support the use of immature oocytes in studies of sperm-zona interaction. We have also analyzed the sources of variability in sperm binding assays, and we make suggestions for the most efficient design of experiments.

Animals↗
PubMed1986

Anaesthesia for heart transplantation. A retrospective study and review.

The anaesthetic records of 261 heart transplant recipients were reviewed. Data collected included demographic characteristics, physical status, results of preoperative cardiac catheterization studies, anaesthetics agents and incidences of complications which may have been related to anaesthetic management. Forty-five patients received a volatile agent (methoxyflurane 31, enflurane 10, halothane 4) and 216 patients were anaesthetized with a high-dose narcotic technique (morphine 122, fentanyl 71, hydromorphone 14, meperidine 9). Hypotension and arrhythmias were correlated with use of volatile and narcotic anaesthetics, respectively. No mortality was associated with anaesthetic management.

Adolescent↗
PubMed1986

Interventions in high-risk occupational cohorts: a cross-sectional demonstration project.

In 1980, the Workers' Institute for Safety and Health began a demonstration project designed to develop a model program of community-based intervention in three cohorts with different workplace exposures and target cancer sites. Program components included identification, notification, medical surveillance, education, social support services (eg, psychosocial, legal, financial, etc), and evaluation. The three cohorts included the Augusta cohort, a group at risk for bladder cancer due to workplace exposure to beta-naphthylamine; the Port Allegany cohort, a group at high risk of cancer associated with a workplace exposure to asbestos; and the Pattern Makers cohort, a group shown to be at increased risk of colorectal cancer. Together, these three projects give a cross-sectional view of possible approaches to educational and medical intervention strategies in diverse situations.

Asbestosis↗
PubMed1986

Seven-year follow-up of workers exposed to 1,2-dibromo-3-chloropropane.

A follow-up report was done of workers exposed to 1,2-dibromo-3-chloropropane (DBCP) 7 years after termination of exposure. A 1977 study of male pesticide workers exposed to DBCP in a California agricultural chemical plant identified many who were azoospermic or oligospermic. Sperm concentration and serum follicle-stimulating hormone (FSH) levels in 44 of these workers were reassessed 5 to 8 years after exposure was terminated in 1977. Two of the eight originally azoospermic workers produced sperm during the follow-up, although only one had normal sperm counts. No increase in sperm production could be detected in men who had low sperm counts in 1977, and elevated serum FSH levels did not drop in oligospermic or azoospermic men. These results suggest that permanent destruction of germinal epithelium occurs in most DBCP-sterile persons.

Follicle Stimulating Hormone↗
PubMed1985

Analysis of 2136 genetic amniocenteses: experience of a single physician.

Between 1979 and 1984, 2136 midtrimester genetic amniocenteses were performed by a single physician at the University of California (Davis) Medical Center. The medical records were reviewed for maternal age, amniocentesis indication, ultrasound findings, location of placenta, location of the needle insertion (transplacental versus nontransplacental), color of the amniotic fluid, results of prenatal testing, complications of procedure, and pregnancy outcome. Follow-up data were available for 88% of the pregnancies. There were 38 miscarriages (1.9%), 18 stillbirths (0.9%), and four neonatal deaths (0.2%), resulting in a total postprocedural loss rate of 3.1%. Miscarriage within 2 weeks of amniocentesis occurred in only 0.4% of procedures (seven of 1918). No significant difference in pregnancy outcome was noted between transplacental and nontransplacental amniocentesis. Greenish brown discolored amniotic fluid was found in 3.6% of procedures (76 of 2136). In this group there was a 14.5% fetal loss rate with an overall 22.4% adverse outcome.

Abortion, Spontaneous↗