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Biomedical subjects

R Wolfe

Publications and source records attributed to R Wolfe.

At least 55 records · Page 3Linked to original sources
PubMed1999

Onset of adolescent eating disorders: population based cohort study over 3 years.

OBJECTIVE: To study the predictors of new eating disorders in an adolescent cohort. DESIGN: Cohort study over 3 years with six waves. SUBJECTS: Students, initially aged 14-15 years, from 44 secondary schools in the state of Victoria, Australia. OUTCOME MEASURES: Weight (kg), height (cm), dieting (adolescent dieting scale), psychiatric morbidity (revised clinical interview schedule), and eating disorder (branched eating disorders test). Eating disorder (partial syndrome) was defined when a subject met two criteria for either anorexia nervosa or bulimia nervosa according to the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV). RESULTS: At the start of the study, 3.3% (29/888) of female subjects and 0.3% (2/811) of male subjects had partial syndromes of eating disorders. The rate of development of new eating disorder per 1000 person years of observation was 21.8 in female subjects and 6.0 in male subjects. Female subjects who dieted at a severe level were 18 times more likely to develop an eating disorder than those who did not diet, and female subjects who dieted at a moderate level were five times more likely to develop an eating disorder than those who did not diet. Psychiatric morbidity predicted the onset of eating disorder independently of dieting status so that those subjects in the highest morbidity category had an almost sevenfold increased risk of developing an eating disorder. After adjustment for earlier dieting and psychiatric morbidity, body mass index, extent of exercise, and sex were not predictive of new eating disorders. CONCLUSIONS: Dieting is the most important predictor of new eating disorders. Differences in the incidence of eating disorders between sexes were largely accounted for by the high rates of earlier dieting and psychiatric morbidity in the female subjects. In adolescents, controlling weight by exercise rather than diet restriction seems to carry less risk of development of eating disorders.

Adolescent↗
PubMed1999

HIRA, a DiGeorge syndrome candidate gene, is required for cardiac outflow tract septation.

DiGeorge syndrome (DGS) is a congenital disease characterized by defects in organs and tissues that depend on contributions by cell populations derived from neural crest for proper development. A number of candidate genes that lie within the q11 region of chromosome 22 commonly deleted in DGS patients have been identified. Orthologues of the DGS candidate gene HIRA are expressed in the neural crest and in neural crest-derived tissues in both chick and mouse embryos. By exposing a portion of the premigratory chick neural crest to phosphorothioate end-protected antisense oligonucleotides, ex ovo, followed by orthotopic backtransplantation to the untreated embryos, we have shown that the functional attenuation of cHIRA in the chick cardiac neural crest results in a significantly increased incidence of persistent truncus arteriosus, a phenotypic change characteristic of DGS, but does not affect the repatterning aortic arch arteries, the ventricular function, or the alignment of the outflow tract.

Animals↗
PubMed1999

A computerised screening instrument for adolescent depression: population-based validation and application to a two-phase case-control study.

Computer-administered questionnaires have been little explored as a potentially effective and inexpensive alternative to pencil and paper screening tests. A self-administered computerised form of the revised Clinical Interview Schedule (CIS-R) was compared with the Composite International Diagnostic Interview (CIDI) in a two-phase study of 2032 Australian high school students (mean age 15.7 years) drawn from a stratified random sample of 44 schools in the state of Victoria, Australia. Prevalence, sensitivity and specificity were estimated using weighting to compensate for the two-phase sampling. Point prevalence estimates of depression using the CIS-R were 1.8% for males and 5.6% for females--an overall prevalence of 3.2%. Prevalence estimates for depression in the past 6 months using the CIDI were 5.2% for males and 16.9% for females--an overall estimate of 12.1%. The CIS-R had a positive predictive value (PPV) of 0.49 and negative predictive value (NPV) of 0.91 for CIDI depression in the past 6 months. Specificity was very high (0.97) but sensitivity low (0.18), indicating that a majority of those with a CIDI-defined depressive episode in the past 6 months were not recognised at a single screening using the CIS-R. Even so, the CIS-R has proved at least as good as any pencil and paper questionnaire in identifying cases for nested case-control studies of adolescent depression. Further exploration of strategies such as serial screening to enhance sensitivity is warranted.

Adolescent↗
PubMed1999

Excellent long-term functional outcome after an operation for anomalous left coronary artery from the pulmonary artery.

OBJECTIVE: The aim of this study was to review the results of operations for anomalous left coronary artery from the pulmonary artery and the late outcome for exercise capacity, left ventricular function, and mitral regurgitation. METHODS: Twenty-one patients underwent operations over an 18-year period (median age, 9 months; range, 6 weeks-26 years) with a median follow-up of 6.5 years (range, 2 months-18 years). In addition to clinical and echocardiographic follow-up, patients at our institution were also investigated with radionuclide scans (n = 10) and treadmill exercise testing (n = 8). RESULTS: There were no operative or late deaths (0%; 95% confidence interval [CI], 0% and 16%). Five patients required support with a left ventricular assist device. Eighteen patients are currently in New York Heart Association class I, and 3 patients are mildly symptomatic. On nuclear gated scan at a mean of 6 years after the operation, the left ventricular ejection fraction was 64% (SD, 3%) at rest and increased to 74% (SD = 3%) on exercise (95% CI for the difference, 6%, 14%; P =.001). Treadmill endurance was normal for age (9.8-14.5 minutes) in those old enough to exercise. On echocardiography (n = 18), the current fractional shortening was 34% (SD, 4%) in the 15 patients with normal or only mildly abnormal ventricular septal motion. Three patients have undergone mitral valve operations. The left ventricular end-diastolic dimension fell from 48 mm (SD, 5.8 mm) before surgery to 35.1 mm (SD, 5.2 mm) at 1 year after the operation, and the fractional shortening increased over the first year from 19.6% (SD, 9.3%) to 32.8% (SD, 5.9%; both P <.001). CONCLUSIONS: Long-term clinical outcome and left ventricular function are good, despite severe left ventricular dysfunction at presentation.

Adolescent↗
PubMed1999

Sample-size calculation for a log-transformed outcome measure.

The outcome measure of interest in clinical trials sometimes requires transformation to the logarithmic scale for analysis. This paper examines sample-size calculation for both independent groups and matched-pairs trials for log-transformed outcomes. For both types of trial, we demonstrate how the calculation can be formulated in terms of a relative treatment effect and a statement of relative variability, both specified on the original scale of measurement. For a comparison of two independent groups, the relative treatment effect is the ratio of group geometric means (or alternatively, group arithmetic means) and the coefficient of variation is used as a summary of relative variability. For a matched-pairs comparison, the appropriate relative treatment effect is the geometric mean of the within-pair ratios, and relative variability can be specified as an upper bound on within-pair ratios under a null hypothesis of the relative effect being equal to 1 (i.e., no difference). We discuss the clinical study that motivated this work and demonstrate the application of the sample-size calculation to this study.

Algorithms↗
PubMed1999

Report of the IDECG Working Group on the modulating effect of stressors on the upper and lower limits of lipid and carbohydrate intake. International Dietary Energy Consultative Group.

The recommended caloric intake should be increased by 2870kJ (670Kcal)/d in the exclusively breast-feeding woman. Of this increase, 10% should be ingested as protein, up to 50% as lipid and no less than 40% as carbohydrate. If weight loss is desired lipid intake can be reduced but carbohydrate intake should be maintained. Of the total energy increment 3% should be supplied by essential fatty acids (linoleic and alpha-linolenic acids) and 0.5% by n-3 fatty acids. The issue of dietary supplementation with long-chain polyunsaturated fatty acids remains for future research.

Dietary Carbohydrates↗
PubMed1999

Genetic counseling and prenatal diagnosis for the mitochondrial DNA mutations at nucleotide 8993.

Mitochondrial genetics is complicated by heteroplasmy, or mutant load, which may be from 1%-99%, and thus may produce a gene dosage-type effect. Limited data are available for genotype/phenotype correlations in disorders caused by mtDNA mutations; therefore, prenatal diagnosis for mtDNA mutations has been hindered by an inability to predict accurately the clinical severity expected from a mutant load measured in fetal tissue. After reviewing 44 published and 12 unpublished pedigrees, we considered the possibility of prenatal diagnosis for two common mtDNA mutations at nucleotide 8993. We related the severity of symptoms to the mutant load and predicted the clinical outcome of a given mutant load. We also used the available data to generate empirical recurrence risks for genetic counseling, which may be used in conjunction with prenatal diagnosis.

Adenosine Triphosphatases↗
PubMed1999

Preliminary investigation of computer stress and the big five personality factors.

This study investigated correlates of personality factors, measured with the Big Five Inventory, with computer users' stress, measured with the Computer Hassles Scale. Based on an analysis of the responses of 95 college students using computers, there was a significant correlation between the computer users' stress and Openness, one of the Big Five personality factors. There was a significant correlation between the Computer Hassles Scale and the somatic complaints and anxiety reactions, typical responses to stress. Hierarchical regression analyses indicated that Neuroticism and Extraversion had a "buffering effect" between computer stressors and typical stress responses. The significant correlation between scores on the Computer Hassles Scale and on Openness was a surprising finding and suggested that additional research was needed to clarify the nature of this relationship.

Adult↗
PubMed1998

The course of early smoking: a population-based cohort study over three years.

AIMS: To examine the uptake and course of smoking in a representative adolescent cohort. DESIGN: Six-wave cohort study. PARTICIPANTS: Secondary school students initially aged 14-15 years at 44 schools in the state of Victoria, Australia. MEASUREMENTS: Computerized questionnaire including 7-day retrospective recall for tobacco use. FINDINGS: Prevalence rates for smoking in the past month rose from 25% to 31% and daily smoking 9% to 18% across the 3-year follow-up. Forty-five per cent of the sample smoked at some point but only 18% were daily smokers at the end-point. High rates of short-term cessation were observed for both experimental and daily smokers, but 70% of daily smokers relapsed within 12 months. Occasional smoking at the outset was the strongest predictor of later daily smoking and was also predictive of lower cessation and higher relapse rates. Parental divorce and parental daily smoking were associated with smoking at the outset and parental smoking was strongly predictive of the course of daily smoking. In contrast, prevalence rates of smoking in a subject's school did not significantly predict either smoking initiation or subsequent course. Female daily smokers were half as likely as males to cease smoking, a finding that accounted for gender differences in smoking prevalence in this sample. CONCLUSIONS: The strength of association between occasional and later daily smoking indicates the importance of primary prevention but the variability in the early course indicates that there should be much scope for promotion of adolescent efforts to quit. Both the diminished likelihood of smoking cessation in young women and parental influences on smoking course deserve further exploration.

Adolescent↗
PubMed1998

The effect of rectally administered steroids on bone turnover: a comparative study.

BACKGROUND: Oral glucocorticoids contribute significantly to the risk of osteoporosis in patients with inflammatory bowel disease. Less well established are the effects of rectally administered steroids on bone metabolism. AIM: To investigate the effects of two widely used rectal foam preparations (prednisolone metasulphobenzoate and hydrocortisone acetate) on biochemical markers of bone turnover. METHODS: Twenty-four patients with active inflammatory bowel disease randomly received a standard course of either prednisolone metasulphobenzoate or hydrocortisone acetate for 2 weeks. Biochemical markers of bone turnover were measured before, during and after treatment. Bone formation markers measured were serum osteocalcin (BGP) and bone-specific alkaline phosphatase (BALP). Urinary deoxypyridinoline (DPD) was measured to assess bone resorption. RESULTS: Disease activity scores improved during treatment (difference in mean Powell-Tuck score = 3.4, 95% CI: 2.0-4.8, P < 0.0001) and were similar in both hydrocortisone and prednisolone-treated groups. There was no significant reduction in BALP or BGP during treatment with either steroid preparation, and urinary DPD did not change significantly during treatment. CONCLUSIONS: During a 2-week course of rectal hydrocortisone acetate or prednisolone metasulphobenzoate, there was no significant change in biochemical markers of bone formation or resorption. These results suggest that pharmacological doses of rectal steroid foam preparations do not significantly impair bone turnover in patients with inflammatory bowel disease.

Administration, Rectal↗
PubMed1998

Hospitalization for gastrointestinal and liver diseases: the effect of socioeconomic and medical supply factors.

A growing body of research has documented significant variation in health care use between communities. As the health care system is transformed, providers and payers should understand the interaction between a community, its sociodemographic characteristics, and its use of health resources. We describe the association between a population's demographic, socioeconomic, and medical resources and hospital use related to gastrointestinal and liver diseases. We used an all-payer hospital discharge database for Michigan from 1986 to 1988. We identified all medical and surgical hospital admissions during this period from two of the Diagnostic Related Group, Major Diagnostic Categories: No. 6, Diseases and Disorders of the Digestive System; and No. 7, Diseases and Disorders of the Hepatobiliary System and Pancreas. We analyzed age- and sex-specific use rates. Finally, we analyzed the influence of sociodemographic variables from the Area Resource File at the county level, on hospital use, using a Poisson regression model. We noted a significant association between increased hospitalizations and increased age in a community. Hospital beds per capita did not influence admission rates overall, although more hospital beds were associated with more medical admissions. Overall, the total physician supply was associated with more admissions. Finally, the most important socioeconomic variable was education. As the level of education of a county increased, hospital admissions decreased dramatically. The transformation of the health care delivery system presents opportunities and challenges. Understanding the underlying epidemiology of disease and how it interacts with a community's socioeconomic and medical resources or medical supply characteristics will be necessary to meet the community's health needs and to ensure the financial viability of providers. This is especially true when payers use a standard payment in a region, such as Medicare's managed care payment, without adjustments for the underlying population characteristics known to influence use.

Adolescent↗
PubMed1998

Depression, anxiety, and smoking initiation: a prospective study over 3 years.

OBJECTIVES: This report considers the extent to which depression and anxiety predict smoking onset in adolescence. METHODS: A 6-wave cohort design was used to study a sample of 14- and 15-year-old students (n = 2032) drawn from 44 secondary schools in the state of Victoria, Australia. The students were surveyed between 1992 and 1995 with a computerized questionnaire that included a 7-day retrospective diary for tobacco use and a structured psychiatric interview. RESULTS: Experimental smokers were 29 times more likely than non-smokers to make a transition into daily use in the subsequent 6 months. Depression and anxiety, along with peer smoking, predicted initiation of experimental smoking. Specifically, depression and anxiety accentuated risks associated with peer smoking and predicted experimentation only in the presence of peer smoking. CONCLUSIONS: The finding that experimental smoking is an overwhelmingly strong predictor of later daily smoking focuses attention on smoking initiation. Depressive and anxiety symptoms are associated with higher risks for initiation through an increased susceptibility to peer smoking influences. Promoting the psychological well-being of adolescents and addressing perceived interpersonal benefits of smoking may play a role in the prevention of adolescent tobacco use.

Adolescent↗
PubMed1997

Social behavior and aggressive problems of cats.

Cats form social groups in which individuals recognize each other, and the cohesiveness of the group is maintained by a variety of amicable behaviors. Agonistic behavior may occur between group members and between group members and nongroup members. Within the domestic environment, agonistic behavior may become a problem when it is directed at housemates or humans. Differential diagnosis and treatment of various problems of aggressive behavior are discussed.

Aggression↗
PubMed1996

Emergency medicine journal clubs.

OBJECTIVE: To ascertain the status of journal club within emergency medicine (EM) residency programs and to describe 3 currently used formats. METHODS: The directors of U.S. Residency Review Committee for Emergency Medicine (RRC-EM)-approved residency programs were surveyed to determine the features of their programs' journal clubs. Responses to 3 questions assessing the degree of satisfaction (5-item scales from very good to very poor) with the "current format," "resident participation," and "faculty participation" from the survey were grouped according to the program director's impressions of resident and faculty "enjoyment" (2 3-item scales) and whether the journal club is a "success" (3-item scale) to develop an overall satisfaction index. Three journal club formats currently in use at EM residencies are described in detail. RESULTS: Of the 101 directors surveyed, 91 (90%) responded. The respondents' overall satisfaction index was highest when the journal club was held in the evening (p < 0.008) or at a faculty member's home (p < 0.0004). The format of the journal club (e.g., by topic, with a statistical focus, with a research design, focus, or as a clinical practice update) was not associated with the overall satisfaction index. CONCLUSION: Journal clubs associated with EM residencies vary in format and perceived success. The 3 representative journal clubs illustrate different format options.

Cross-Sectional Studies↗
PubMed1995

Effect of estradiol 17 beta on pressor responses of rat mesenteric bed to norepinephrine, K+, and U-46619.

We reinvestigated the effect of estradiol 17 beta on the responses of adrenergic and nonadrenergic vasoconstrictors characterized it in terms of steroid specificity, time course, and the role of classic estrogen receptors. We evaluated the effect of estradiol 17 beta on the pressor responses of isolated perfused rat mesenteric vascular bed (McGregor's preparation). Estradiol 17 beta (7-700 nM) significantly increased the pressor response to bolus applications of norepinephrine (NE) (p < 0.05). However, estradiol 17 beta did not significantly increase the responses to endogenous NE release induced by electrical field stimulation. Other steroids, testosterone, and the 17 alpha isomer of estradiol (7 and 700 nM) were ineffective. Estradiol 17 beta (700 nM) also significantly increased the maximum pressor response of rat mesenteric preparation to both the prostaglandin endoperoxide analogue U-46619 and to K+. The potentiation by estradiol 17 beta of mesenteric vasoconstriction elicited by NE, K+, and U-46619 was rapid (2-8 min), suggesting that a nuclear receptor may not be involved. This notion received further support in that significant potentiation of the NE-induced pressor response was also observed with estradiol 17 beta conjugated to albumin (700 nM), but not when electrical field stimulation was used. The conjugate increased the effect of all NE concentrations. Its effect was also more consistent (p < 0.01) than that elicited by free estradiol 17 beta. The dose-response curve was shifted to the left, and the maximum effect was increased. These data suggest that estradiol 17 beta may possess rapid nongenomic actions unrelated to nuclear receptor binding and gene transcription.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1995

Effect of testosterone treatment on vasoconstrictor response of left anterior descending coronary artery in male and female pigs.

Androgens may be risk factors in the pathogenesis of coronary artery disease by promoting coronary vasoconstriction. We studied the effect of testosterone treatment on coronary vascular reactivity of male and female domestic pigs treated for 2 weeks with either placebo or testosterone 10 mg/kg subcutaneous (s.c.) pellets. Vascular reactivity was studied in ring segments (4-5 mm) isolated from the left anterior descending coronary artery (LAD). No significant sex difference was noted in the response of LAD segments from placebo-treated male and female animals to KCl and prostaglandin F2 alpha (PGF2 alpha). Androgen treatment increased the maximum response (Tmax) of intact vessels to KCl from 3,647 +/- 689 mg in controls to 8,939 +/- 1,284 mg in testosterone-treated males (p < 0.01) and from 3,405 +/- 669 to 10,524 +/- 1,663 mg in testosterone-treated female pigs (p < 0.01). Testosterone similarly increased the response to PGF2 alpha 10(-6) M from a mean of 2,149 +/- 1,036 to 3,163 +/- 867 mg in males (p < 0.05) and from 2,076 +/- 810 to 3,565 +/- 578 mg in female segments (p < 0.05). Endothelial denudation significantly decreased the potentiating effect of testosterone treatment in males to both KCl and PGF2 alpha (p < 0.05), but not in segments from females. Our data show that testosterone treatment potentiates contractility of porcine LAD segments to both receptor- and nonreceptor-mediated agonists. In male pigs, this effect may be mediated by an effect on endothelium.

Animals↗