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Biomedical subjects

J R Wilkins

Publications and source records attributed to J R Wilkins.

13 recordsLinked to original sources
PubMed1991

Parental occupation and intracranial neoplasms of childhood: anecdotal evidence from a unique occupational cancer cluster.

Near the end of the data-collection phase of a case-control interview study of environmental factors and childhood brain tumors, an unusual space-time cluster was revealed. Not only had six genetically unrelated children been diagnosed with a primary intracranial tumor in a recent 2.4 year period in a rural county in Ohio, but each child had one parent employed by the same company (two mothers, four fathers). This represents an observed/expected ratio greater than 70 (p much less than 0.001). All tumors were microscopically confirmed, and all case parents worked at the facility in question for at least 1 year prior to conception, during the index pregnancy, and for at least 6 months after birth. The place of parental employment was an electronics firm (Standard Industrial Classification [SIC] group number 367, electronic components and accessories), where more than 100 chemical compounds are used by the company in a manufacturing process. Results of the cluster investigation are described, including a description of the case series. This cancer cluster is unique in that the index case series is composed of the offspring of workers, not the workers themselves.

Adolescent↗
PubMed1991

A comparison of median hearing thresholds from U.S. Navy and U.S. Army audiometric data bases.

This study examined 1984 monitoring audiometric data from U.S. Navy (military and civilian) employees whose workplace required a mandatory hearing conservation program. Median hearing thresholds were compared in U.S. Navy employees, U.S. Army employees also monitored by a hearing conservation program, and a standard population from the First National Health and Nutrition Survey. Age group and frequency-specific comparisons were included. Results at 4 kHz and 6 kHz demonstrated higher median thresholds in the Navy populations that were significantly higher by clinical and statistical criteria. Possible reasons for the differences are given.

Adult↗
PubMed1990

Paternal occupational exposure to electromagnetic fields and neuroblastoma in offspring.

Investigators in Texas have reported an association between paternal employment in jobs linked with exposure to electromagnetic fields and risk of neuroblastoma in offspring. In an attempt to replicate this finding, the authors conducted a case-control study in Ohio. A total of 101 incident cases of neuroblastoma were identified through the Columbus (Ohio) Children's Hospital Tumor Registry. All cases were born sometime during the period 1942-1967. From a statewide roster of birth certificates, four controls were selected for each case, with individual matching on the case's year of birth, race, and sex, and the mother's county of residence at the time of the (index) child's birth. Multiple definitions were employed to infer the potential for paternal occupational exposure to electromagnetic fields from the industry/occupation statements on the birth certificates. Case-control comparisons revealed adjusted odds ratios ranging in magnitude from 0.5 to 1.9. For two of the exposure definitions employed--both of which are similar to one used by the Texas investigators--the corresponding odds ratios were modestly elevated (odds ratios = 1.6 and 1.9). Notably, the magnitude of these odds ratios is not inconsistent with the Texas findings, where the exposure definition referred to yielded an odds ratio of 2.1. Because the point estimates in this study are imprecise, and because the biologic plausibility of the association is uncertain, the results reported here must be interpreted cautiously. However, the apparent consistency between two independent studies suggests that future evaluation of the association is warranted.

Adolescent↗
PubMed1990

Parental occupation and intracranial neoplasms of childhood: results of a case-control interview study.

In 1983-1984, the authors conducted a case-control study of environmental factors and childhood brain tumor risk. Cases (n = 110) were identified through the tumor registry of a pediatric hospital and matched controls (n = 193) through random digit dialing. In addition to parental occupational histories, telephone interviews elicited information about potential confounders and hypothesized risk factors for childhood brain tumors. Relying primarily on the Hoar et al. (J Occup Med 1980;22:722-6) job-exposure matrix, the authors examined parental employment characteristics in relation to the relevant developmental periods. Paternal employment in several industries (agriculture, construction, metal, and food and tobacco) and in several occupations (agriculture, benchwork, and transportation) was associated with excess risk. The range of notably elevated odds ratios was 2.0-3.3, with all confidence intervals including 1.0 except one. Elevated but unstable odds ratios were also found for both paternal and maternal employment in jobs "clustered" together because of common exposures. For both approaches to exposure classification, the greatest excess risks were consistently demonstrated for parental jobs held in the preconception period. Job-exposure matrix analyses indicated that case fathers were more likely than control fathers to have had jobs linked with aromatic amino and aromatic nitro compounds (range of notably elevated (and unstable) odds ratios, 3.4-4.4), but here the greatest excess risks were exhibited in the postnatal period. Few associations emerged for maternal employment characteristics, although this is probably explained by the relatively small number of women employed in jobs outside the home.

Adolescent↗
PubMed1985

Affinity-labeled plasma somatomedin-C/insulinlike growth factor I binding proteins. Evidence of growth hormone dependence and subunit structure.

By using disuccinimidyl suberate, we have covalently cross-linked 125I-labeled somatomedin-C (Sm-C)/insulinlike growth factor I to specific binding proteins in human plasma. In unfractionated plasma samples from normal and acromegalic donors, 125I-Sm-C binding-protein complexes with relative molecular weights (Mr) of 160,000, 135,000, 110,000, 80,000, 50,000, 43,000-35,000, and 28,000-24,000 were consistently observed. In contrast, the 43,000-35,000-mol wt species were frequently the only specific complexes observed in hypopituitary plasma and were consistently more intensely labeled in such samples. Reduction of samples with beta-mercaptoethanol did not alter the electrophoretic pattern of these 125I-Sm-C binding-protein complexes. All Sm-C binding proteins, with the exception of the 43,000-35,000-mol wt complex, were adsorbed by concanavalin A-Sepharose. When acromegalic or normal plasma was fractionated on a Sephadex G-200 column and affinity labeled, the same complexes that were adsorbed by concanavalin A were found in fractions that eluted near the gamma-globulin peak. On the other hand, the 43,000-35,000-mol wt complex consistently eluted in size-appropriate fractions near the albumin peak. These data suggest that the growth hormone (GH)-dependent Sm-C binding protein, represented by the 160,000-mol wt complex, is in some way composed of smaller species, i.e., the 135,000-, 110,000-, 80,000-, 50,000-, and 28,000-24,000-mol wt complexes. Acid incubation of plasma prior to Sephadex G-200 chromatography results in the elimination of specific 125I-Sm-C binding-protein complexes which elute near gamma-globulin and a concurrent increase in the labeling intensity of the 28,000-24,000-mol wt complexes. We speculate, therefore, that each of the GH-dependent Sm-C binding-protein complexes represents an oligomer composed of 28,000-24,000-mol wt protomers. The 43,000-35,000-mol wt species is not dependent upon GH and appears to represent a different type of Sm-C binding protein.

Affinity Labels↗
PubMed1978

Multichannel electrochemical microbial detection unit.

A compact multichannel unit for electrochemical detection of microorganisms that automatically displays detection time length is described. This unit was successfully tested with various members of the Enterobacteriaceae group.

Bacteriological Techniques↗
PubMed1978

Use of platinum electrodes for the electrochemical detection of bacteria.

Platinum electrodes with surface area ratios of four to one were used to detect and enumerate a variety of gram-positive and gram-negative organisms. Linear relationships were established between inoculum size and detection time. End points for platinum electrodes were similar to those obtained with a platinum-reference electrode combination. Shape of the overall response curves and length of detection times for gram-positive organisms were markedly different than those for the majority of gram-negative species. Platinum electrodes are better than the platinum-reference electrode combination because of cost, ease of handling, and clearer definition of the end point.

Bacteria↗
PubMed1976

Electrochemical method for the early detection of urinary-tract infections.

A method for detecting the presence of bacteria in urine based on measuring a change in potential between two electrodes was tested in a clinical microbiology laboratory. Initial tests were conducted with 13 bacteria commonly associated with urinary-tract infections; all of the test organisms were detected within 2--9 hours. A linear relationship was established between inoculum size and the time an increase in voltage was observed on a strip-chart recorder. No response was seen with sterile urine, but urine samples inoculated with Escherichia produced the expected positive response. One hundred twenty-eight urine specimens from hospitalized persons were simultaneously tested by the electrochemical detection method (ECDM) and by conventional bacteriologic procedures. Ninety-four per cent of 49 positive samples with counts of 10(5) organisms per ml. or more were detected within 4 hours and 100% at 10 hours with the ECDM. Twenty-nine specimens with counts less than 10(5) cells per ml. were detected in 3.5 to 9 hours; two samples (8%) in this group were positive within 4 hours. Fifty samples were negative for bacterial growth, and no increase in voltage was found with these samples.

Bacteria↗
PubMed1975

Bacterial aerosolization from an ultrasonic cleaner.

An ultrasonic device used for cleaning surgical instruments was found to produce a significant microbial aerosol. No correlation was found between the concentration of aerosol generated and the bacterial contamination in the cleaning solution. Table top contamination around the cleaner was due essentially to splash and dripping, and not from the settling of the aerosol. Recommendations are made for cleaning and disinfection protocols.

Aerosols↗
PubMedDate not supplied

Uterine cervical cancer risk in cigarette smokers: a meta-analytic study.

We conducted a meta-analytic study to measure the risk of uterine cervical cancer in former and current smokers. A literature search from 1966 to 1988 identified 139 MEDLINE citations. Of these, five studies reported appropriate and complete data for meta-analysis. A recent study conducted by the authors was also included. The graphical and variance-based methods of meta-analysis consistently demonstrated a significantly excessive risk of cervical cancer in current smokers, but not in former smokers. The powers of the analyses involving former smokers were between 0.72 and 0.99, depending on the degree of confounding attributed to unmeasured variables. Thus, it was unlikely that sample size accounted for the null association observed in former smokers. These findings have important medical implications for women in light of the prevalence of cigarette smoking. During regular gynecologic screening examinations, health care professionals may have considerable impact by counseling women about the risk of cervical cancer in smokers. Antismoking messages should be strongly directed toward women in the lower educational and socioeconomic levels to have the greatest impact on the incidence of cervical cancer.

Adult↗