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Biomedical subjects

G Weidner

Publications and source records attributed to G Weidner.

At least 19 recordsLinked to original sources
PubMed2006

Cross-sectional correlates of fasting hyperinsulinaemia in post-menopausal women of different ethnic origin.

AIMS: In a large ethnically diverse nationwide sample of post-menopausal women we explored the relationship between fasting insulin levels, ethnicity, and a wide range of anthropometric, socio-economic, and lifestyle factors. METHODS: Subjects were post-menopausal women aged 50-79 years without diagnosed diabetes mellitus comprising a subsample (n = 3500) of the Women's Health Initiative (WHI) Clinical Trial and Observational Study. In a cross-sectional survey at baseline, we analysed the association between ethnicity and fasting insulin using analysis of covariance procedures and identified independent correlates of hyperinsulinaemia, defined by the 75th percentile cut point for each ethnic group. RESULTS: Fasting insulin levels were higher among African-American and Hispanic women than among non-Hispanic White or Asian women. These differences persisted after adjustment for age, educational attainment, total and central body obesity, adult weight change, family history of diabetes, smoking status, alcohol consumption, use of menopausal hormone therapy and physical activity. Higher levels of body mass index, waist-hip ratio, adult weight gain, and lower levels of total and moderate or strenuous recreational activity were independent correlates of fasting hyperinsulinaemia. Habitual walking was also inversely associated with fasting insulin. CONCLUSIONS: In this cross-sectional analysis, fasting insulin levels were higher among African-American and Hispanic post-menopausal women as compared with non-Hispanic White and Asian women. In addition, obesity, adult weight gain, and low levels of moderate or strenuous physical activity were independently associated with hyperinsulinaemia.

Black or African American↗
PubMed2001

The Aspergillus nidulans homoaconitase gene lysF is negatively regulated by the multimeric CCAAT-binding complex AnCF and positively regulated by GATA sites.

In beta-lactam-antibiotic-producing fungi, such as Aspergillus (Emericella) nidulans, L-alpha-aminoadipic acid is the branching point of the lysine and penicillin biosynthesis pathways. To obtain a deeper insight into the regulation of lysine biosynthesis genes, the regulation of the A. nidulans lysF gene, which encodes homoaconitase, was studied. Band-shift assays indicated that the A. nidulans multimeric CCAAT-binding complex AnCF binds to two of four CCAAT motifs present in the lysF promoter region. AnCF consists at least of three different subunits, designated HapB, HapC, and HapE. In both a delta hapB and a delta hapC strain, the expression of a translational lysF-lacZ gene fusion integrated in single copy at the chromosomal argB gene locus was two to three-fold higher than in a wild-type strain. These data show that AnCF negatively regulates lysF expression. The results of Northern blot analysis and lysF-lacZ expression analysis did not indicate a lysine-dependent repression of lysF expression. Furthermore, mutational analysis of the lysF promoter region revealed that two GATA sites matching the GATA consensus sequence HGATAR positively affected lysF-lacZ expression. Results of Northern blot analysis also excluded that the global nitrogen regulator AreA is the responsible trans-acting GATA-binding factor.

Aspergillus nidulans↗
PubMed2000

Hostility, social support, and carotid artery atherosclerosis in the National Heart, Lung, and Blood Institute Family Heart Study.

This cross-sectional study investigates the association of hostility and social support (measured by standardized instruments) to carotid artery atherosclerosis in men and women with a high familial risk for coronary heart disease (CHD) and those with low to medium risk. The hypothesis was that high hostility and low social support would have a stronger association in subjects with a familial predisposition to CHD. There were 535 low- to medium-risk women, 491 low- to medium-risk men, 1,950 high-risk women, and 1,667 high-risk men in the study. The extent of carotid artery atherosclerosis was assessed by B-mode ultrasound imaging. A lesion was defined as an intimal-medial far wall thickness of 1 mm in the common, internal, or carotid bifurcation, or identification of plaque at any site. Odds ratios and their 95% confidence intervals were calculated using generalized estimating equations (GEE) for logistic regression. Family was specified as the clustering variable, and robust SEEs were obtained that account for dependence of the data within families. After controlling for age, education, body mass index, ever having smoked, ever drinking > 5 drinks a day, and metabolic index, hostility was significantly associated with increased odds of carotid lesions in only high-risk women. High-risk women showed a significantly reduced odds of carotid lesions with high social support, but the extent of this protection was reduced when age and education were included in the equation. A combination of high hostility and low social support was associated with higher odds than hostility alone in both high-risk men and women. These results suggest that women with a high familial predisposition for CHD may be more vulnerable to cardiovascular influences from hostility and social support than high-risk men or men and women with low to medium risk.

Adult↗
PubMed2000

Why do men get more heart disease than women? An international perspective.

Biological, behavioral, and psychosocial contributions to the gender gap in coronary heart disease (CHD) are discussed. Although CHD is the Number 1 cause of death for both sexes in the industrialized world, CHD mortality rates between these countries are larger than those between men and women, suggesting that biological factors are not the sole influences on the gender gap in CHD. Traditional coronary risk factors cannot explain the rapid increase in CHD mortality among middle-aged men in many of the newly independent states of eastern Europe. However, eastern European men score higher on stress-related psychosocial coronary risk factors (e.g., social isolation, vital exhaustion) than men living in the West. Comparisons between the sexes also reveal gender differences in psychosocial and behavioral coronary risk factors, including excessive alcohol consumption and smoking, favoring women. Overall, it appears that men's coping with stressful events may be less adaptive physiologically, behaviorally, and emotionally, contributing to their increased risk for CHD.

Adult↗
PubMed1998

Hostility, social support, and coronary heart disease in the National Heart, Lung, and Blood Institute Family Heart Study.

This cross-sectional study investigated the association of hostility and social support to coronary heart disease (CHD) in 2 groups of men and women: those with a familial predisposition for CHD (high-risk sample) and a randomly selected group. The hypothesis was that hostility and low social support would be associated with CHD, and would have a greater effect in the high-risk group. The random sample contained 2,447 individuals (47.1% male) from 576 families, and the high-risk sample consisted of 2,300 people (45.5% male) from 542 families. Odds ratios (OR) and their 95% confidence intervals were calculated using generalized estimating equations (GEE) for logistic regression. Family was specified as the clustering variable, and robust SEEs were obtained to account for dependence of the data within families. After controlling for age, education, body mass index, exercise, smoking history, drinking history, and drinking >5 drinks a day, hostility was associated with a history of coronary bypass surgery or coronary angioplasty in high-risk men (OR 1.21) and a history of myocardial infarction in high-risk women (OR 1.39). High-risk women with high social support had reduced odds of a previous myocardial infarction (OR 0.76), whereas women with high network adequacy in the random sample had reduced risk of myocardial infarction (OR 0.41) and angina (OR 0.49). A ratio of high hostility to low social support was associated with past myocardial infarction in high-risk women (OR 2.47) and a history of angina (OR 2.02) in the random sample men. These results suggest that high hostility and low social support are associated with some manifestations of CHD after controlling for adverse health behaviors.

Adult↗
PubMed1998

Development of a homologous transformation system for the human pathogenic fungus Aspergillus fumigatus based on the pyrG gene encoding orotidine 5'-monophosphate decarboxylase.

A homologous transformation system for the opportunistic fungal pathogen Aspergillus fumigatus was developed. It is based on the A. fumigatus pyrG gene, encoding orotidine 5'-monophosphate decarboxylase, which was cloned and sequenced. Transformation of both Aspergillus (Emericella) nidulans and A. fumigatus pyrG mutant strains by the use of protoplasts or electroporation established the functionality of the cloned gene. DNA sequencing of the A. fumigatus pyrG1 mutant allele revealed that it encodes a truncated, non-functional, PyrG protein. Transformation of an A. fumigatus pyrG1 mutant with a plasmid carrying the novel pyrG2 allele constructed by in vitro mutagenesis yielded prototrophic transformants following recombination between both mutation sites. Analysis of transformants carrying the entire plasmid showed that up to 45% of integration had occurred at the pyrG locus. This provides a tool to target defined genetic constructs at a specific locus in the A. fumigatus genome in order to study gene regulation and function.

Amino Acid Sequence↗
PubMed1997

The Aspergillus nidulans lysF gene encodes homoaconitase, an enzyme involved in the fungus-specific lysine biosynthesis pathway.

In filamentous fungi, lysine is synthesized via the alpha-aminoadipate pathway. In order to gain insight into this fungus-specific pathway (to date, no genes for enzymes of this pathway in filamentous fungi have been cloned) the lysine auxotrophic mutant LysF88 of Aspergillus nidulans was studied. HPLC and 1H-NMR analyses revealed that LysF88 accumulated homocitric acid in the culture supernatant. In addition, both the LysF88 mutant strain and LysF deletion strain (LysFKO) described here showed hardly any homoaconitase activity, indicating that lysF encodes homoaconitase. The lysF gene was cloned by complementation of the LysF88 mutant and sequenced. It has a size of 2397 bp, including a single intron of 72 bp. The two exons encode an open reading frame (ORF) of 2325 bp. The calculated M(r) of the homoaconitase protein (775 amino acids) is 83,943. A major and a minor transcript begin at positions -28 and -32, respectively. The 3' end of the lysF cDNA showed a poly(A) tail commencing at position +2647 following a 250 bp untranslated region after the lysF stop codon. A putative polyadenylation signal sequence (TATAAA) is located 49 bp upstream of the polyadenylation site. Computer analysis revealed 55% amino acid sequence identity between the products of the putative homoaconitase ORF of A. nidulans and that of the recently sequenced homologous Saccharomyces cerevisiae. The similarity was particularly obvious in a region of cysteine residues, which are characteristic of an iron-sulfur cluster, implying that homoaconitase contains such a cluster. The homoaconitases of A. nidulans and S. cerevisiae share only 20% sequence identity with S. cerevisiae aconitase. The pH optimum for the activity of A. nidulans homoaconitase in 0.1 M potassium phosphate buffer is between pH 8.1 and pH 8.6. Homoaconitase exhibited an apparent K(m) of 1.1 mM toward homoisocitric acid. The specific activity of homoaconitase was reduced by up to six-fold in mycelia grown in the presence of L-lysine, suggesting that it is regulated by lysine.

Amino Acid Sequence↗
PubMed1997

Relationship of job strain to standard coronary risk factors and psychological characteristics in women and men of the Family Heart Study.

This study reports on standard coronary risk factors (plasma lipids and lipoproteins, blood pressure, heart rate, age, body mass index) and psychosocial variables (job strain, Type A behavior, hostility, illnesses, medical and psychological symptoms, health-damaging behavior) in a community sample of 324 employed men, 203 employed women, and 155 female homemakers. Employed women reported less hostility and fewer illnesses than homemakers and had lower cholesterol levels than homemakers and men. Job characteristics were unrelated to standard coronary risk factor levels in both sexes, but predicted medical symptoms and health-damaging behavior in men. These findings suggest that employment is associated with enhanced medical and physical well-being among women and point to possible behavioral and psychological pathways by which job strain may adversely influence men's health.

Blood Pressure↗
PubMed1996

Molecular characterization of the genes encoding pyruvate formate-lyase and its activating enzyme of Clostridium pasteurianum.

Formate is the major source of C1 units in many species of the genus Clostridium. In this study we have cloned and characterized the genes encoding pyruvate formate-lyase and its activating enzyme of Clostridium pasteurianum. The genetic and transcriptional organizations of the genes and the high level of homology exhibited by the respective gene products to their Escherichia coli counterparts indicate strong evolutionary conservation of these enzymes.

Acetyltransferases↗
PubMed1993

Effects of demand and decision latitude on cardiovascular reactivity among coronary-prone women and men.

According to the Job Strain Model, high demand/low decision latitude jobs may be associated with increased risk of developing coronary heart disease. In further analyses of a laboratory study, the authors hypothesized that Type A behavior and/or hostility moderate the effects of demand, decision latitude, and gender on cardiovascular reactivity, a putative mechanism for the development of coronary disease. With multiple regressions, it was found that scores on the Framingham Type A scale interacted with demand and decision latitude to affect diastolic blood pressure changes, such that Type Bs in the low demand/high decision latitude condition showed the smallest increases in diastolic blood pressure. Among men, hostility accounted significantly and positively for variance in systolic blood pressure changes in addition to that accounted for by high demand. These results suggest that coronary-prone traits may potentiate, or add to, the effects that stressful environments have on health outcomes.

Adolescent↗
PubMed1993

The effects of task demand and decision latitude on cardiovascular reactivity to stress.

This study investigated the effects of task demand (absence or presence of time pressure) and decision latitude (choice or no choice over a task) on cardiovascular and affective responses to stressful tasks among 70 college students. Subjects also rated whether they felt under pressure and the extent to which they felt in control. Time pressure was related to elevated systolic blood pressure (SBP) responses among men and increased negative affect for both sexes. Lack of choice over the task also resulted in increased negative affect in both sexes. The least stressful condition--having a choice in the absence of time pressure--resulted in reduced negative affect. In addition to the effects of manipulated decision latitude and demand, perceptions of being in control were associated with reduced SBP among women who had a choice. Perceived control also contributed to reduced negative affect among men. These results suggest that the postulated negative effects of high demand and low decision latitude (ie, job strain) on cardiovascular health may be mediated in part by increased cardiovascular reactivity and negative affect.

Adolescent↗
PubMed1992

Improvements in hostility and depression in relation to dietary change and cholesterol lowering. The Family Heart Study.

OBJECTIVE: To describe changes in negative emotions among participants of a cholesterol-lowering study. DESIGN: Cohort study. Quantitative evaluation of changes in negative emotions in relation to diet and plasma cholesterol levels before and after a 5-year dietary intervention program aimed at reducing plasma cholesterol levels. SETTING: Community-dwelling families of the Family Heart Study, Portland, Oregon. PARTICIPANTS: One hundred forty-nine men and 156 women from 233 families (mean age, 37.7 years). MEASUREMENTS: Changes in negative emotions including depression and aggressive hostility as measured by the Hopkins Symptom Checklist (SCL-90). RESULTS: Improvement in overall emotional state was noted for the entire sample. Those who consumed a low-fat, high complex-carbohydrate diet at the end of the study showed significantly greater improvements in depression (P = 0.044; difference in improvement, 2.9 points) and aggressive hostility (P = 0.035; difference in improvement, 3.3 points) as well as a reduction in their plasma cholesterol levels (P = 0.024; difference in improvement, 2.7%) compared with those who ate a high-fat "American diet." CONCLUSIONS: Participation in a cholesterol-lowering program may not be associated with a worsening in emotional state. To the contrary, improvements in diet appear to be associated with reductions in depression and aggressive hostility as well as with lowered plasma cholesterol levels.

Adult↗