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Biomedical subjects

D R Williams

Publications and source records attributed to D R Williams.

At least 91 records · Page 5Linked to original sources
PubMed1999

Gender and the socioeconomic gradient in mortality.

Despite considerable evidence documenting a strong and persistent relationship between socioeconomic position and mortality, recent research suggests that this association may be weaker among women. In our examination of gender differences in the socioeconomic gradient in mortality, we argue that this inconsistency arises from the failure to consider the ways in which gender is a fundamental constituent of socioeconomic position. The data used are from the Panel Study of Income Dynamics. Respondents, including all household heads and their partners, aged 29 years and older in 1972 (N = 5,665; 56% female), were followed until 1991, death, or attrition. Discrete time event history analysis was used to examine the predictors of death between 1972 and 1991. Of the key socioeconomic predictors, years of education was measured at baseline, while earned income was a time-varying covariate. We find no gender differences in the effect of respondents' own socioeconomic positions on their mortality risk. However, increasing spousal income raises men's odds of dying, while the opposite is true for women. Our results raise questions about the prevailing view that the socioeconomic gradient in mortality is weaker among women. Moreover, gender differences in the effects of spousal earnings on mortality risk suggest that their labor market rewards have fundamentally different meanings for women and men.

Adult↗
PubMed1999

The prevalence, distribution, and mental health correlates of perceived discrimination in the United States.

The survey data presented here are on the national prevalences of major life-time perceived discrimination and day-to-day perceived discrimination; the associations between perceived discrimination and mental health; and the extent to which differential exposure and differential emotional reactivity to perceived discrimination account for the well-known associations between disadvantaged social status and mental health. Although more prevalent among people with disadvantaged social status, results show that perceived discrimination is common in the total population, with 33.5 percent of respondents in the total sample reporting exposure to major lifetime discrimination and 60.9 percent reporting exposure to day-to-day discrimination. The associations of perceived discrimination with mental health are comparable in magnitude to those of other more commonly studied stressors, and these associations do not vary consistently across subsamples defined on the basis of social status. Even though perceived discrimination explains only a small part of the observed associations between disadvantaged social status and mental health, given its high prevalence, wide distribution, and strong associations with mental health, perceived discrimination needs to be treated much more seriously than in the past in future studies of stress and mental health.

Adult↗
PubMed1998

Postmarketing surveillance study of a non-chlorofluorocarbon inhaler according to the safety assessment of marketed medicines guidelines.

OBJECTIVE: To evaluate the safety of a non-chlorofluorocarbon metered dose salbutamol inhaler. DESIGN: This was a postmarketing surveillance study, conducted under formal guidelines for company sponsored safety assessment of marketed medicines (SAMM). A non-randomised, non-interventional, observational design compared patients prescribed metered doses of salbutamol delivered by inhalers using either hydrofluoroalkane or chlorofluorocarbon as the propellant. Follow up was three months. SETTING: 646 general practices throughout the United Kingdom. SUBJECTS: 6614 patients with obstructive airways disease (1667 patient years of exposure). MAIN OUTCOME MEASURES: Proportions of patients who were: admitted to hospital for respiratory diseases, reported adverse side effects, or withdrew because of adverse affects. RESULTS: There were no significant differences between the hydrofluoroalkane (HFA 134a) and chlorofluorocarbon inhaler groups in relation to the proportions of patients admitted to hospital for respiratory diseases (odds ratio 0.75; 95% confidence interval 0.51 to 1.08) or the proportions who reported adverse events (1.01; 0.88 to 1.17). However, more patients using the hydrofluoroalkane inhaler than the chlorofluorocarbon inhaler withdrew because of adverse events (3.8% and 0.9% respectively). CONCLUSION: The hydrofluoroalkane inhaler was as safe as the chlorofluorocarbon inhaler when judged by hospital admissions and adverse affects. The study design successfully fulfilled the recommendations of the guidelines. Differences between postmarketing surveillance studies and randomised clinical trials in assessing safety were identified. These may lead to difficulties in the design of postmarketing surveillance studies.

Adult↗
PubMed1998

Socioeconomic factors, health behaviors, and mortality: results from a nationally representative prospective study of US adults.

CONTEXT: A prominent hypothesis regarding social inequalities in mortality is that the elevated risk among the socioeconomically disadvantaged is largely due to the higher prevalence of health risk behaviors among those with lower levels of education and income. OBJECTIVE: To investigate the degree to which 4 behavioral risk factors (cigarette smoking, alcohol drinking, sedentary lifestyle, and relative body weight) explain the observed association between socioeconomic characteristics and all-cause mortality. DESIGN: Longitudinal survey study investigating the impact of education, income, and health behaviors on the risk of dying within the next 7.5 years. PARTICIPANTS: A nationally representative sample of 3617 adult women and men participating in the Americans' Changing Lives survey. MAIN OUTCOME MEASURE: All-cause mortality verified through the National Death Index and death certificate reviews. RESULTS: Educational differences in mortality were explained in full by the strong association between education and income. Controlling for age, sex, race, urbanicity, and education, the hazard rate ratio of mortality was 3.22 (95% confidence interval [CI], 2.01-5.16) for those in the lowest-income group and 2.34 (95% CI, 1.49-3.67) for those in the middle-income group. When health risk behaviors were considered, the risk of dying was still significantly elevated for the lowest-income group (hazard rate ratio, 2.77; 95% CI, 1.74-4.42) and the middle-income group (hazard rate ratio, 2.14; 95% CI, 1.38-3.25). CONCLUSION: Although reducing the prevalence of health risk behaviors in low-income populations is an important public health goal, socioeconomic differences in mortality are due to a wider array of factors and, therefore, would persist even with improved health behaviors among the disadvantaged.

Adult↗
PubMed1998

Expression of autoactivated stromelysin-1 in mammary glands of transgenic mice leads to a reactive stroma during early development.

Extracellular matrix and extracellular matrix-degrading matrix metalloproteinases play a key role in interactions between the epithelium and the mesenchyme during mammary gland development and disease. In patients with breast cancer, the mammary mesenchyme undergoes a stromal reaction, the etiology of which is unknown. We previously showed that targeting of an autoactivating mutant of the matrix metalloproteinase stromelysin-1 to mammary epithelia of transgenic mice resulted in reduced mammary function during pregnancy and development of preneoplastic and neoplastic lesions. Here we examine the cascade of alterations before breast tumor formation in the mammary gland stroma once the expression of the stromelysin-1 transgene commences. Beginning in postpubertal virgin animals, low levels of transgene expression in mammary epithelia led to increased expression of endogenous stromelysin-1 in stromal fibroblasts and up-regulation of other matrix metalloproteinases, without basement membrane disruption. These changes were accompanied by the progressive development of a compensatory reactive stroma, characterized by increased collagen content and vascularization in glands from virgin mice. This remodeling of the gland affected epithelial-mesenchymal communication as indicated by inappropriate expression of tenascin-C starting by day 6 of pregnancy. This, together with increased transgene expression, led to basement membrane disruption starting by day 15 of pregnancy. We propose that the highly reactive stroma provides a prelude to breast epithelial tumors observed in these animals.

Animals↗
PubMed1998

Ventricular fibrillation following butane gas inhalation.

We report a case of out of hospital defibrillation in a 15-year-old schoolgirl who developed ventricular fibrillation (VF) in association with butane gas inhalation. Although defibrillation performed by an attending paramedic was successful in restoring a cardiac output, her clinical course was complicated by severe neurological impairment. Reports of successful resuscitation following volatile substance abuse are rare and we believe this is the first documented evidence of VF associated with butane gas. This case illustrates the tragedy of such abuse in fit young people and we briefly review the literature.

Administration, Inhalation↗
PubMed1998

The prevalence of multiple sclerosis in the Leeds Health Authority.

OBJECTIVES: To determine the prevalence of multiple sclerosis in the Leeds Health District. METHODS: Multiple sources of case ascertainment were used-namely, neurology departments, hospital episode statistics, general practitioners, the Leeds branch of the Multiple Sclerosis Society, the West Yorkshire Multiple Sclerosis Therapy Centre, community physiotherapists and occupational therapists, the Leeds Wheelchair Centre, and the Young Disabled Unit. Data collection was from retrospective analysis of hospital and primary care case records. A population based incidence register was established by prospectively registering all new patients with diagnoses of multiple sclerosis. RESULTS: On prevalence day, 30 April 1996, 712 people with multiple sclerosis were identified living in Leeds (population 732,061), giving a prevalence of 97/10(5). The prevalence for definite and probable multiple sclerosis was 84/10(5), and for suspected multiple sclerosis it was 13/10(5). The sex ratio of prevalent people with multiple sclerosis was 2.79 to 1 women to men. The mean age of prevalent cases was 51 years, the mean age at symptom onset was 34 years, and the mean duration of disease was 16 years. Forty cases were prospectively reported as incident cases from 1 November 1995 to 1 February 1996. CONCLUSIONS: The prevalence of multiple sclerosis in Leeds was found to be similar to that in the south of the United Kingdom but lower than that in Scotland. There is no evidence of a latitudinal gradient of increasing prevalence of multiple sclerosis from the south to the north of England.

Adult↗
PubMed1998

The effects of haemofiltration on cefazolin levels during cardiopulmonary bypass.

Ultrafiltration has been shown to affect cardiac drug concentrations during cardiopulmonary bypass (CPB), based on their respective pharmacological properties. In an attempt to understand the aetiology of sternal wound infections, a study was performed to eliminate the use of ultrafiltration as a possible cause. We compared cefazolin levels at three time intervals during the course of routine CPB with ultrafiltration to those levels in a control group in which ultrafiltration was not used. Our results indicate that there is little difference in the rate of decay of antibiotic levels with or without the use of a haemoconcentrator. This implies that ultrafiltration procedures do not put the patient at any increased risk for infection and that additional measures beyond that which we would normally use at our institution need not be taken.

Blood Proteins↗
PubMed1998

The African American minister as a source of help for serious personal crises: bridge or barrier to mental health care?

Using data from the National Survey of Black Americans, this article explores the role of African American ministers in the help seeking of African Americans for serious emotional problems. The authors explore which demographic characteristics and psychosocial factors are related to contacting Black clergy for help, whether certain types of personal problems increase the likelihood of clergy contact, and whether those who go to ministers are also likely to seek help from other professional help sources. Results indicate that women are more likely than men to seek help from ministers. People with economic problems are less likely to contact clergy, while those with death or bereavement problems are more likely to seek help from the clergy. Regardless of the type or severity of the problem, those who contact clergy first are less likely to seek help from other professionals. It is recommended that African American clergy and mental health professionals engage in a mutual exchange of information to increase access to professional care among African Americans with serious personal problems.

Adult↗
PubMed1998

Cell wall active antifungal compounds produced by the marine fungus Hypoxylon oceanicum LL-15G256. II. Isolation and structure determination.

Fermentations of the marine fungus Hypoxylon oceanicum (LL-15G256) were found to have potent antifungal activity. Isolation and purification of the antifungal agents provided two classes of compounds, macrocyclic polylactones and the lipodepsipeptides 15G256 gamma (1), 15G256 delta (2) and 15G256 epsilon (3). The isolation and structure elucidation of the lipodepsipeptides, all containing D-glutamate, L-serine, and the rare amino acid beta-ketotryptohan, are described in this paper.

Antifungal Agents↗
PubMed1998

Determining permeability and diffusion rates in polymer films and packaging materials.

This article describes a rapid and effective means of calculating diffusion and permeability constants for a range of polymer films and packaging materials with various vapours. The sealed diffusion-cell method, in combination with a high performance DVS-1 gravimetric analysis system, provides fundamental data for thin films and rapid screening of composite films when designing advanced packaging systems or calculating potential shelf-life of packaged devices.

Diffusion↗
PubMed1998

Core competency-based education, certification, and practice: the nurse-midwifery model.

It has been more than 70 years since the first nurse-midwives came to practice in the United States, and over 20 years since the American College of Nurse-Midwives (ACNM) established nationally recognized standards and core competencies for nurse-midwifery education, certification, and practice. Certified nurse-midwives are licensed in all 50 states and in the District of Columbia (DC) and have prescribing privileges in 45 states plus DC. More recent standard-setting activities include the establishment of a national mechanism for continuing competency assessment; adoption of the bachelor's degree as the minimum academic requirement for certification; development of national standards for education and certification of direct entry midwives; and placement of an 8-year time limit on certificates.

Certification↗
PubMed1997

Induction of enzymes involved in molting hormone (ecdysteroid) inactivation by ecdysteroids and an agonist, 1,2-dibenzoyl-1-tert-butylhydrazine (RH-5849).

Molting in insects is regulated by molting hormones (ecdysteroids). The major active hormone, 20-hydroxyecdysone, is formed by ecdysone 20-monooxygenase-catalyzed hydroxylation of ecdysone. During times of decreasing hormone titers, inactivation occurs by several routes including (i) 26-hydroxylation and further oxidation to the 26-oic acid, (ii) formation of various conjugates (e.g. phosphates), and (iii) in Lepidoptera in particular, ecdysone oxidase-catalyzed formation of 3-dehydroecdysteroid, which is reduced to 3-epiecdysteroid, followed by phosphotransferase-catalyzed formation of phosphate conjugates. Administration of the nonsteroidal ecdysteroid agonist RH-5849 (1,2-dibenzoyl-1-tert-butylhydrazine), but not 20-hydroxyecdysone, to tobacco hornworm (Manduca sexta) resulted in induction of midgut cytosolic ecdysone oxidase and ecdysteroid phosphotransferase activities. In addition, both 20-hydroxyecdysone and RH-5849 caused induction of ecdysteroid 26-hydroxylase activity in midgut mitochondria and microsomes, whereas 20-hydroxylase was induced to a lesser extent by 20-hydroxyecdysone in mitochondria and by either RH-5849 or 20-hydroxyecdysone in microsomes. Commensurate with induction of the enzymes by ecdysteroid and RH-5849 is a requirement for RNA and protein synthesis, without precluding indirect mechanisms. These results indicate that molting hormone stimulates at least one universal route of its own inactivation by inducing ecdysteroid 26-hydroxylase activity and are discussed in relation to an analogous phenomenon observed for vitamin D inactivation in vertebrates.

Animals↗
PubMed1997

Antenatal risk factors for childhood diabetes mellitus; a case-control study of medical record data in Yorkshire, UK.

Environmental risk factors for childhood insulin-dependent diabetes mellitus (IDDM) have been investigated using data abstracted from the obstetric records of mothers participating in a population-based case-control study of children (0-15 years) diagnosed with IDDM during 1993-1994. A univariate analysis of 196 age and sex matched sets (129 triplets, 67 pairs) gave significantly raised odds ratios (OR) for mothers over 35 years (OR 2.13, 95%CI 1.04-4.36) and the following exposures in pregnancy: amniocentesis (3.85, 1.34-11.04), oedema, proteinuria and/or hypertensive disorders (1.62, 1.03-2.54), excessive weight gain (7.12, 1.50-33.79) and complications in labour (1.49, 1.00-2.21). The risk previously associated with caesarean deliveries was confirmed and the trend of increasing risk with age was significant. Adjusting separately for mothers with IDDM (4 cases, 0 control subjects), parity and small for gestational age failed to have any influence on the pregnancy risk factors or caesarean delivery. Case mothers undergoing amniocentesis were significantly younger compared to their control counterparts (p = 0.02) and the majority were given the test to determine fetal maturity, late in pregnancy, rather than to identify chromosomal abnormalities. Oedema, proteinuria and/or hypertension conferred an increased risk throughout pregnancy, particularly in the first two trimesters. No specific pattern of risk was present for any age group. Multivariate modelling of the significant OR, using conditional logistic regression, retained excessive weight gain as significant. The overall results present a risk profile of older mothers whose babies may be exposed to adverse intrauterine conditions and delivery by caesarean section.

Adolescent↗