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Biomedical subjects

G S Wilkinson

Publications and source records attributed to G S Wilkinson.

At least 37 records · Page 2Linked to original sources
PubMed1996

Effects of prenatal care on neonates born to drug-using women.

This study examined whether prenatal care ameliorates the adverse effects of illicit drug use during pregnancy. We reviewed medical records of 336 women who delivered at the university hospital for results of urine drug screens, maternal history, infant outcome, and presence of prenatal care. Ninety-one women tested positive for illicit drugs, of whom 60 obtained prenatal care. We associated use of marijuana with increased risk of fetal distress; cocaine use with decreased birth weight, smaller head circumference, anemia, and meconium-stained amniotic fluid; and multiple drug use with decreased weight and meconium-stained fluid. Drug-using women who obtained prenatal care delivered infants of greater weight and with larger head circumferences than did those who obtained no care (p < .05). These results confirm the adverse effects of illicit drug use during pregnancy.

Adolescent↗
PubMed1996

Migration and evolution of lesser long-nosed bats Leptonycteris curasoae, inferred from mitochondrial DNA.

We used sequence variation within 297 bp of control region mitochondrial DNA (mtDNA) amplified from 53 lesser long-nosed bats, Leptonycteris curasoae (Phyllostomidae: Glossophaginae) captured at 13 locations in south-western United States and Mexico and one site in Venezuela to infer population structure and possible migration routes of this endangered nectar- and fruit-eating species. Phylogenetic analysis using maximum parsimony and UPGMA confirmed species and subspecies distinctions within Leptonycteris and revealed two clades exhibiting 3% sequence divergence within the Mexican subspecies, L. c. yerbabuenae. Even though many roots contained L. c. yerbabuenae from both clades, weak population structure was detected both by a correlation between genetic differentiation, F(st), and geographical distance and by a cladistic estimate of the number of migration events required to align bat sequences with geographical location on maximum parsimony, as compared to random, trees. Three results suggest that L. c. yerbabuenae are more likely to migrate between sites along the Pacific coast of Mexico or along the foothills of the Sierra Madre Occidental than between these regions. (1) Seventeen of 20 bats which shared an identical sequence were captured up to 1800 km apart but within the same putative migration corridor. (2) Residuals from a regression of F(st) on distance were greater between than within these regions. (3) Fewer migration events were required to align bats with these two groups than expected from random assignment. We recommend analysing independent genetic data and monitoring bat visitation to roost sites during migration to confirm these postulated movements.

Animals↗
PubMed1995

Biomarker monitoring of a population residing near uranium mining activities.

We investigated whether residents residing near uranium mining operations (target population), who are potentially exposed to toxicants from mining waste, have increased genotoxic effects compared with people residing elsewhere (reference population). Population surveys were conducted, and 24 target and 24 reference residents were selected. The selected subjects and controls were matched on age and gender and they were nonsmokers. Blood samples were collected for laboratory studies. The standard cytogenetic assay was used to determine chromosome aberration frequencies, and the challenge assay was used to investigate DNA repair responses. We found that individuals who resided near uranium mining operations had a higher mean frequency of cells with chromosome aberrations and higher deletion frequency but lower dicentric frequency than the reference group, although the difference was not statistically significant. After cells were challenged by exposure to gamma-rays, the target population had a significantly higher frequency of cells with chromosome aberrations and deletion frequency than the reference group. The latter observation is indicative of abnormal DNA repair response in the target population.

Biomarkers↗
PubMed1995

Substance use during pregnancy and peripartum complications in a triethnic population.

To study the effects of illicit drug use during pregnancy on maternal health, we reviewed the records of women who delivered at the University of Texas Medical Branch between June 1, 1989, and February 28, 1990, for peripartum history and results from drug urinalysis screens. After controlling for age at delivery, gravidity, race/ethnicity, and use of alcohol or tobacco, elevated relative risk estimates were observed among women who had positive urinalysis for syphilis, gonorrhea, pregnancy-induced hypertension, chorioamnionitis, asthma, and postpartum hemorrhage. These findings confirm that pregnant women who use illicit drugs are at increased risk for serious health complications.

Adult↗
PubMed1994

Perinatal morbidity associated with violence experienced by pregnant women.

OBJECTIVE: We investigated whether physical assault is independently associated with an adverse obstetric outcome. STUDY DESIGN: We compared the perinatal outcomes of 32 indigent women who reported being physically abused during pregnancy with those of 352 control subjects who denied ever being assaulted. Patients were classified into the appropriate category on the basis of a structured interview. Logistic regression analyses were performed to estimate the relative risk of adverse outcome while adjusting for confounders. RESULTS: Women assaulted in the current pregnancy were twice as likely to have preterm labor as compared with those who denied assault. In addition, crude odds ratios showed a twofold increased risk of chorioamnionitis in assault victims. No difference between abused and nonabused women was noted in the prevalence of preterm delivery, pregnancy-induced hypertension, cesarean section, meconium staining, infant birth weight, Apgar scores, intrauterine growth retardation, fetal distress, fetal death, neonatal seizures, sepsis, or admission to the intensive care unit. CONCLUSIONS: This study demonstrates that physical assault during pregnancy is associated with preterm labor and chorioamnionitis. Screening for ongoing assault should be incorporated into routine prenatal care to identify women at risk of complications.

Adult↗
PubMed1992

Smoking, alcohol, dentition and diet in the epidemiology of oral cancer.

This matched case-control study was conducted in Western New York. The smoking, alcohol consumption, dental hygiene and diet of 290 cases were compared with those of 290 sex-, age-, and neighbourhood-matched controls. The results confirm earlier findings that cigarette smoking and alcohol consumption impart substantial risk of oral cancer. The results also confirm that poor oral hygiene increases the risk of oral cancer, although this effect is much smaller than those of cigarette smoking and alcohol consumption. The results suggest that, of macronutrients, intake of fat is more likely than those of protein or carbohydrate to be related to risk. Of micronutrients, calcium, sodium, riboflavin and retinol are associated with risk, while thiamin, niacin, and dietary fibre are associated with decreased risk. Although patterns of dietary effects are discernable, these effects are in general much weaker than are those of smoking and alcohol consumption.

Aged↗
PubMed1992

Prevalence of physical and sexual assault in pregnant adolescents.

Few studies have addressed the prevalence of violence among pregnant adolescents. We interviewed 342 pregnant teenagers 17 years of age or younger for a history of assault; 9% reported physical assault, 8% sexual assault, and 8% both physical and sexual assault. Of those physically abused, 40% had been hit during pregnancy. The most common perpetrator of physical assault was a member of their family of origin as compared to a mate (46% versus 33%), although a boyfriend or spouse was the attacker in 80% of cases in which abuse had increased during pregnancy. The face or neck was the most common site of contact. A total of 14% reported being hit in the abdomen, one-third of them while pregnant. We conclude that a significant proportion of pregnant teenagers have experienced violence and therefore should be screened routinely for a history of abuse.

Adolescent↗
PubMed1992

Violence and its relationship to substance use in adolescent pregnancy.

We surveyed 342 pregnant adolescents 17 years old and younger for a history of physical or sexual assault and substance use to investigate whether victims of childhood violence are at increased risk of smoking and using alcohol or drugs. A total of 95% of new patients who attended the university's teen pregnancy clinic between May 8, 1989, and December 8, 1990, were interviewed. Substance use was reported seven times more often in those with a history of combined physical and sexual assault, five times more frequently by those who had been sexually assaulted, and three times more often in those who had been physically assaulted than adolescents without a history of assault. Violence was associated with substance use in all ethnic groups although this relationship was modified by ethnicity. Among Hispanics, an association was observed between physical assault and tobacco use. Sexual and combined physical and sexual assault were strongly associated with use of alcohol among blacks. All categories of violence were associated with drug use among all ethnic groups. When use of each substance was analyzed by the adolescent's relationship to the perpetrator, drug use was most strongly associated with assault by a mate, whereas tobacco or alcohol use was more often associated with assault by a member of the victim's family of origin.

Adolescent↗
PubMed1991

Drug abuse and other risk factors for physical abuse in pregnancy among white non-Hispanic, black, and Hispanic women.

We investigated prevalence and risk factors associated with physical abuse among a tricultural population of 501 pregnant women who attended a public prenatal clinic. Twenty percent (98/501) reported being physically abused; 29% (28/98) stated that abuse occurred during pregnancy. More white non-Hispanic women reported previous abuse than did black or Hispanic women. Battered women more frequently were divorced or separated, were of greater parity, smoked, used alcohol, or admitted to illicit drug use than did women who were not battered. An increased risk of previous physical abuse was observed among white non-Hispanic and black women who used alcohol (odds ratios = 3.0 and 6.0) or drugs (odds ratios = 2.1 and 3.7) but not among Hispanic women. Odds ratios of 4.7 for cocaine use among white non-Hispanic women, 4.7 for marijuana use among black women, and 5.8 for tobacco use among Hispanic women were observed. This is the first study to report the effects of race on the association between physical abuse of pregnant women and substance use.

Black or African American↗
PubMed1991

Length and sequence variation in evening bat D-loop mtDNA.

Length variation in D-loop mitochondrial DNA was observed after amplification with the polymerase chain reaction (PCR) in 28% of 195 evening bats, Nycticeius humeralis, from seven colonies. Nucleotide sequences of PCR products show that this heteroplasmy is characterized by an 81-bp region which is tandemly repeated five to eight times. Southern blots using PCR products as probes on HaeIII genomic digests confirm the presence of heteroplasmy. Furthermore, densitometry of electrophoresed PCR products from 109 mother-offspring pairs indicate that heteroplasmy is stably transmitted from mother to offspring with one exception: a heteroplasmic offspring had a homoplastic mother and sib. Nucleotide sequences from this family reveal that a repeat duplication and deletion occurred. The observed mutation rate per generation, mu, for length polymorphism is comparable to an independent estimate, mu = 10(-2), based on hierarchical diversity statistics. With the exception of the repeat nearest the proline tRNA gene, sequence similarities between repeats within bats are consistent with a model of concerted evolution due to unidirectional replication slippage. Selection is inferred to act on the first repeat because in comparison to other repeats it has the least sequence divergence among bats, the fewest transversions, and the lowest minimum free energy associated with folding.

Animals↗
PubMed1991

Leukemia among nuclear workers with protracted exposure to low-dose ionizing radiation.

We conducted an analysis of leukemia mortality and protracted exposure to low-dose ionizing radiation. We used data from seven published epidemiologic studies of nuclear workers that reported individual monitoring information for radiation exposure. We found 83 leukemia deaths among white males from a combined total of more than 1.4 million person-years. We calculated an overall relative risk for leukemia of 1.5, after adjustment for age and calendar time, for workers with cumulative occupational doses of 10 mSv (1 rem) or greater, compared with those with cumulative doses of less than 10 mSv. An adjusted relative risk of 1.8 was observed when individuals with 10-50 mSv (1-5 rem) were compared with those who had cumulative occupational doses of less than 10 mSv. The adjusted relative risk for those with doses greater than 50 mSv relative to those with doses less than 10 mSv was 1.2, although the data were especially sparse in this dose range. These combined data indicate a small elevated risk of leukemia for doses of ionizing radiation under 50 mSv.

Follow-Up Studies↗
PubMed1991

Mortality among workers exposed to external ionizing radiation at a nuclear facility in Ohio.

In a cohort mortality study of white men employed by the Mound Facility (1947 through 1979), observed deaths did not exceed those expected based on US death rates for the overall cohort or for the subcohort monitored for external ionizing radiation. Among the radiation-monitored subcohort, mortality for workers with cumulative radiation doses of at least 10 mSv was not significantly increased when compared with mortality for coworkers with cumulative doses of less than 10 mSv. A significant dose-response based on a Mantel-Haenszel test of trend was observed for all leukemias. However, when a death from chronic lymphatic leukemia, a type of leukemia generally not regarded as radiogenic, was removed from the analyses, the strength of the dose-response was reduced.

Cohort Studies↗
PubMed1988

Mortality among workers at a nuclear fuels production facility.

A retrospective cohort mortality study was conducted in a population of workers employed at a facility with the primary task of production of nuclear fuels and other materials. Data for hourly and salaried employees were analyzed separately by time period of first employment and length of employment. The hourly (N = 6,687 with 728 deaths) and salaried (N = 2,745 with 294 deaths) employees had a mortality experience comparable to that of the United States and, in fact, exhibited significant fewer deaths in many categories of diseases that are traditionally associated with the healthy worker effect. Specifically, fewer deaths were noted in the categories of all causes, all cancers, cancer of the digestive organs, lung cancer, brain cancer (hourly workers only), diabetes, all diseases of the circulatory system, all respiratory diseases, all digestive system diseases, all diseases of the genitourinary system (hourly only), and all external causes of death. A statistically significant, and as yet unexplained increase in leukemia mortality (6 observed vs. 2.18 expected) appeared among a subset of the hourly employees, first hired before 1955, and employed between 5-15 years.

Cohort Studies↗
PubMed1987

Mortality among plutonium and other radiation workers at a plutonium weapons facility.

Mortality among 5,413 white males who were employed for at least two years at a plutonium weapons facility was investigated to measure risks from exposures to low levels of plutonium and external radiation. When compared with US death rates, fewer deaths than expected were found for all causes of death, all cancers, and lung cancer. No bone cancer was observed. An excess of brain tumors was found for the cohort in general. Elevated rate ratios for all causes of death and all lymphopoietic neoplasms were found when employees with plutonium body burdens greater than or equal to 2 nCi were compared with those with body burdens less than 2 nCi, while accounting for age, calendar period, and induction time. Increased rate ratios were also found for esophageal, stomach, colon, and prostate cancers, and for lymphosarcomas and reticulum cell sarcomas. No elevated rate ratios were noted for bone and liver cancers. When employees with cumulative exposures greater than or equal to 1 rem were compared with those with exposures less than 1 rem, elevated rate ratios were found for myeloid leukemia, lymphosarcoma and reticulum cell sarcoma, liver neoplasms, and unspecified brain tumors. No overall dose-response relationships were found for plutonium or external radiation exposures. Standardized rate ratios increased, however, as plutonium body burden levels increased for all causes, all cancers, and digestive cancers at five years induction time. Standardized rate ratios also increased as external radiation exposure categories increased for all lymphopoietic cancers and unspecified brain tumors for a two-year induction period. With the exception of analyses of combined categories of death, and perhaps of lung cancer, confidence limits were wide, indicating limited precision. Nevertheless, these findings suggest that increased risks for several types of cancers cannot be ruled out at this time for individuals with plutonium body burdens of greater than or equal to 2 nCi. Plutonium-burdened individuals should continue to be studied in future years.

Air Pollutants, Radioactive↗
PubMed1985

Mortality among workers at the Pantex weapons facility.

We compared total and cause-specific mortality for workers at the Pantex nuclear weapons assembly facility employed between 1951 and 31 December 1978 with expected mortality based on U.S. death rates. We observed significantly fewer deaths than expected from all causes of death, all cancers, digestive cancers, lung cancer, arteriosclerotic heart disease, and digestive diseases. There were no causes of death which occurred significantly more frequently than expected. Analyses of worker mortality by duration of employment, time since first employment, and radiation exposure greater than 1.00 rem produced similar results. We found no evidence that mortality from any cause of death was increased as a result of employment at Pantex.

Adult↗
PubMed1984

Brain tumors at a nuclear facility.

In response to an observed excess risk of brain tumor deaths among workers at the Rocky Flats Nuclear Facility (Colorado), a case-control study of all (n = 16) primary brain tumor deaths occurring among white males employed during 1952 through 1977 was conducted to investigate their relationship with occupational radiation/nonradiation exposures. For each case, four controls were individually matched on year of birth and period of employment. Although limited by a small number of cases, our study showed no statistically significant association between brain tumor death and exposure to internally deposited plutonium, external radiation, or other occupational risk factors.

Adult↗
PubMed1983

An evaluation of demographic differences in the utilization of a cancer information service.

A detailed empirical evaluation of the utilization of a cancer public telephone information program was conducted. This paper reports demographic differences between utilizers and the general population. It was found that utilization varied according to socioeconomic status, area of residence, age and sex. The greatest proportion of users were females, from the higher social classes, city residents and 20-39 years of age. Attempts to look at interrelationships among these variables did not produce any consistent findings.

Adult↗