Biomedical subjects

K A Matthews

Publications and source records attributed to K A Matthews.

At least 73 records · Page 4Linked to original sources

PubMed1995

Psychological stress and immunological responsiveness in normally cycling, follicular-stage women.

Nineteen women in the follicular stage of their menstrual cycles were assessed for immunological responsiveness to a 50-min series of three psychological tasks which reliably elicit cardiovascular and neuroendocrine stress responses. Ten follicular-stage women not subjected to stress served as controls. Stress decreased lymphocyte responsiveness to PHA and PWM, percent of CD4+ cells and the ratio of CD4+/CD8+ cells. Conversely, stress increased natural killer cell number and cytolytic activity, white blood cell, lymphocyte, T and B cell count. Except for natural killer cell number, none of these changes was exhibited by controls. Most of these stress responses are similar to those reported for men and form the basis for a continuing study of the effects of reproductive hormones and stress on cardiovascular and immunological function in women.

Adult↗

PubMed1995

Are job characteristics related to fibrinogen levels in middle-aged women?

This study examined whether employment status or job characteristics thought to be stressful were related to fibrinogen level in a sample of 161 healthy middle-aged women. Employed women had higher fibrinogen levels than did nonemployed women. Moreover, among employed women, those who perceived high levels of job stress or low support from their bosses had elevated fibrinogen, independent of menopausal status. Perception of low support from one's boss was related to higher fibrinogen levels only among premenopausal women or postmenopausal women who were not using hormone replacement therapy. These results are consistent with the notion that stress associated with some job characteristics influences levels of fibrinogen in women.

Adult↗

PubMed1995

Stress-induced hemoconcentration of blood cells and lipids in healthy women during acute psychological stress.

This study examined the effects of psychological stress on hemoconcentration in women. Hematologic and hemodynamic variables were assessed in 17 women before and after a 3-min speech task. Significant changes in hematocrit, hemoglobin levels, red and white blood cell (WBC) count, and calculated plasma volume occurred during psychological stress (all ps < .05). Significant increases were also observed for total cholesterol, triglycerides, high density lipoprotein cholesterol, low density lipoprotein cholesterol, and free fatty acid (FFA; all ps < .05) during stress. After statistically correcting for the hemoconcentration effects of decreased plasma volume during stress, only WBC count and FFA concentration remained significantly elevated during the stress task (p < .006 and p < .05, respectively). In sum, acute stress alters hemoconcentration in women, which in turn can account for most stress-induced changes in lipids.

Adult↗

PubMed1995

Effects of surgical menopause on psychological characteristics and lipid levels: the Healthy Women Study.

The authors examined the effects of surgical menopause, with or without hormone replacement therapy (HRT), on psychosocial functioning and lipid levels in a population-based study of initially premenopausal women. Within 5 years of study entry, 28 women underwent hysterectomy, with 9 retaining their ovaries and 19 having bilateral salpingo oophorectomy (BSO), and with 173 premenopausal women as a comparison group. Women undergoing hysterectomy reported fewer stress symptoms and a more optimistic attitude at follow-up, whereas BSO cases without HRT had lower mean total high-density lipoprotein (HDL) and HDL2, relative to premenopausal women. Subject to limited power, the authors' findings suggest that surgical menopause among middle-aged women does not lead to negative psychological outcomes but that BSO in the absence of hormone use has significant adverse effects on the HDL and HDL2.

Adaptation, Psychological↗

PubMed1995

Weight threshold and blood pressure in a lean black population.

Hypertension is virtually absent in very lean rural African populations but is becoming more common in higher-weight urban African populations and is very common in predominantly obese Westernized black populations. This implies that there is a threshold above which weight is related to blood pressure. We studied urban Nigerian civil servants, a lean population in transition toward a more Westernized lifestyle. Blood pressure, fat-related measurements, fasting insulin, physical activity, alcohol intake, macronutrient intake, and electrolyte excretion were measured in 500 male and 299 female civil servants in Benin City, Nigeria, in 1992. Median body mass index (BMI) was 21.5 kg/m2 in men and 24.0 kg/m2 in women. Examination of age-adjusted mean blood pressure across quantiles of BMI in men and women suggested a threshold of 21.5 kg/m2 below which blood pressure was not correlated with BMI. Above this threshold blood pressure was correlated with BMI. Comparison of groups above and below the lower BMI threshold found that differences in blood pressure-BMI covariation were not explained by differences in alcohol intake, caloric or macronutrient intake, or electrolyte excretion. Physical activity was higher in men below the threshold. Fasting insulin and waist-hip ratio were strongly correlated with BMI even in this very lean population but neither was independently related to blood pressure. We conclude that there is a threshold below which little relationship between blood pressure and weight is observed. Above this threshold even at levels considered lean in US blacks, weight is a major determinant of blood pressure in this population of African blacks, which shares ancestry with US blacks.

Adult↗

PubMed1994

Influence of the perimenopause on cardiovascular risk factors and symptoms of middle-aged healthy women.

OBJECTIVE: To determine the changes in cardiovascular risk factors and psychological and physical symptoms that occur during the perimenopause. DESIGN: Cohort study of 541 healthy middle-aged premenopausal women followed up through the menopause. SETTING: General community. PARTICIPANTS: After a baseline evaluation taken at study entry, 152 women ceased menstruating for 3 months (not due to surgery) and were not using hormone replacement therapy, and were reevaluated in a similar protocol (perimenopausal examination); 105 of the 152 were evaluated a third time when they had ceased menstruating for 12 months and were not using hormone replacement therapy (postmenopausal examination). One hundred nine premenopausal women who were repeatedly tested constituted a comparison group. MAIN OUTCOME MEASURES: Levels of lipids and lipoproteins, triglycerides, fasting glucose and insulin, blood pressure, weight, height, and standardized measures of psychological symptoms. RESULTS: Women who became perimenopausal showed increased levels of cardiovascular risk factors, which were similar in magnitude to those experienced by the comparison group of premenopausal women. Perimenopausal women reported a greater number of symptoms, especially hot flashes, cold sweats, joint pain, aches in the skull and/or neck, and being forgetful; reports of hot flashes at the perimenopausal examination were associated with low concentrations of serum estrogens. Menopausal status was not associated with depressive symptoms. Perimenopausal women who became postmenopausal showed a decline in the level of high-density lipoprotein-2-cholesterol (means, 0.53 to 0.43 mmol/L [20.6 to 16.7 mg/dL]) and a gradual increase in the level of low-density lipoprotein cholesterol (means, 3.14 to 3.33 mmol/L [121.3 to 128.8 mg/dL]), whereas symptom reporting declined. CONCLUSIONS: During mid-life, women experience adverse changes in cardiovascular risk factors and a temporary increase in total number of reported symptoms, with no change in depression. Preventive efforts to reduce the menopause-induced increase in cardiovascular risk factors should begin early in the menopausal transition.

Blood Glucose↗

PubMed1994

Care and feeding of Drosophila melanogaster.

The information provided here should allow you to begin working with Drosophila. Mine your colleagues for alternative approaches, improvements, and refinements and develop your own. If you find a new and better way to do any aspect of fly work, take the time to share it with your colleagues through bionet.drosophila or DIN.

Animals↗

PubMed1994

Are cardiovascular reactors to asocial stress also reactors to social stress?

The authors tested the generalizability of measures of cardiovascular reactivity to asocial and social stress among fathers, mothers, and their adolescent sons. Results showed significant associations between reactivity to individual psychomotor tasks and to conflict resolution only for mothers, suggesting that laboratory measures of reactivity obtained during asocial tasks are of limited value in predicting reactivity during social tasks. Given that interpersonal constructs are important to risk for cardiovascular diseases, these findings point to the importance of measuring cardiovascular reactivity during social stress, not only during asocial achievement stress.

Adolescent↗

PubMed1994

Coffee consumption: relationship to blood lipids in middle-aged women.

BACKGROUND: There is controversy about the relationship between coffee intake and blood lipids in women and many studies fail to control for potential confounding factors. METHODS: In 1983 and 1984, 541 randomly selected premenopausal women were recruited from a list of licenced drivers, aged 42-50, within selected areas in Allegheny County, Pennsylvania. They were invited to participate in a 5-year study of biological and behavioural changes associated with menopause. At baseline and the first follow-up visit, lipoprotein, lipid and apoprotein levels, physical activity, dietary intake and coffee consumption were measured. Pearson correlations between coffee consumption and the various lipid values were calculated. Multivariate analyses, which controlled for the potential confounding effects of body mass index, alcohol intake, percent of calories from carbohydrate and fat, number of cigarettes smoked per day, physical activity level, and age in months, were also employed to investigate the relationships. RESULTS: Mean coffee consumption for the group was 3.35 cups of coffee per day at baseline and 3.02 cups per day at follow-up. Results of analyses of correlation between coffee consumption and blood lipids as well as multiple regressions to control for menopausal status at follow-up were non-significant (P > 0.05) for all blood lipid values with the exception of triglycerides, which were inversely related to coffee consumption at follow-up. CONCLUSIONS: These results do not support a relationship between coffee consumption and lipoprotein, lipid or apoprotein levels with the exception of an inverse relationship between coffee consumption and triglyceride level at follow-up.

Adult↗

PubMed1994

Effects of vitamin A deficiency and repletion on rat glucagon secretion.

To determine whether vitamin A is involved in pancreatic alpha cell function, we tested for (a) effects of vitamin A deficiency on glucagon release from perifused islets and perfused pancreases, and (b) the presence of cytosolic retinol-binding proteins (CRBP) and retinoic acid-binding proteins (CRABP), in the glucagon-secreting alpha cell line, ln-R1-G9. Arginine 19 mM plus glucose 2.8 mM-stimulated glucagon secretion was markedly impaired in islets and pancreases of vitamin A-deficient rats or rats that had at some time been cycled through vitamin A deficiency (ever A-def) despite repletion with retinoids for 2-4 weeks. Insulin secretion was impaired likewise. Repletion starting early in the development of vitamin A deficiency and for a longer period of time (18 or 60 days) did not restore glucagon secretion, but did normalize insulin secretion. CRBP and CRABP were present in ln-R1-G9 cells. We conclude that (a) vitamin A deficiency is associated with a defect in glucagon secretion; (b) The defect in secretion occurs early in the course of vitamin A deficiency; (c) The defect persists despite repletion; and (d) The requirement of vitamin A for secretion and the presence of CRBP and CRABP in glucagon-secreting cells support a physiologic role for vitamin A at the alpha cell level.

Animals↗

PubMed1994

Employment status and depressive symptoms in middle-aged women: a longitudinal investigation.

OBJECTIVES: This study investigated the psychological effects of paid employment and nonemployment, cross-sectionally and longitudinally, in 541 middle-aged women. METHODS: Women were seen for an extensive baseline evaluation and were reevaluated in an identical manner 3 years later. They were divided into four "synthetic" cohorts, based upon employment status at these two assessments. RESULTS: At baseline, nonemployed women reported higher levels of depressive symptoms than employed women, with nonemployed women with less education, low support from family and friends, or low marital satisfaction the most symptomatic. Symptoms decreased in women who were nonemployed initially but employed at the later exam; in all other groups, symptoms increased. Unlike the cross-sectional findings, however, the longitudinal findings showed that women who were nonemployed at baseline and had low levels of education, social support, or marital satisfaction did not benefit more from subsequent employment than did their counterparts who had high levels of these factors. CONCLUSIONS: New paid work may have a positive effect on mood for middle-aged women. However, given the contradictions between our cross-sectional and longitudinal results, caution should be exercised in drawing conclusions from cross-sectional studies that likely confound employment status, symptoms, and moderating variables.

Adult↗

PubMed1993

Psychological predictors of hypertension in the Framingham Study. Is there tension in hypertension?

OBJECTIVE: To test the hypothesis that heightened anxiety, heightened anger intensity, and suppressed expression of anger increase the risk of hypertension, using the Framingham Heart Study. DESIGN: A cohort of men and women without evidence of hypertension at baseline were followed up for 18 to 20 years. Baseline measures of anxiety (tension), anger symptoms, and expression of anger (anger-in and anger-out) were taken, along with biological and behavioral predictors of hypertension (initial systolic blood pressure, heart rate, relative weight, age, hematocrit, alcohol intake, smoking, education, and glucose intolerance). PARTICIPANTS: A total of 1123 initially normotensive persons (497 men, 626 women) were included. Analyses were stratified by age (45 to 59 or > or = 60 years) and gender. MAIN OUTCOME MEASURES: Hypertension was defined as either taking medication for hypertension or blood pressures higher than 160/95 mm Hg at a biennial examination. RESULTS: In univariate analyses, middle-aged men who went on to develop hypertension had greater baseline anxiety levels than men who remained normotensive (P = .04). Older hypertensive men had fewer anger symptoms at baseline (P = .04) and were less likely to hold their anger in (P = .01) than normotensives. In multivariate Cox regression analysis including biological predictors, anxiety remained an independent predictor of hypertension in middle-aged men (P = .02). Among older men, anger symptoms and anger-in did not remain significant predictors in the multivariate analysis. Further analysis showed that only middle-aged men with very high levels of anxiety were at increased risk (relative risk, 2.19; 95% confidence interval, 1.22 to 3.94). No psychological variable predicted hypertension in middle-aged or older women in either univariate or multivariate analyses. CONCLUSIONS: The results indicate that among middle-aged men, but not women, anxiety levels are predictive of later incidence of hypertension.

Aged↗

PubMed1993

Changes in and stability of hostile characteristics: results from a 4-year longitudinal study of children.

Changes in and stability of hostility characteristics and their relationship to age, sex, and family support were examined among 108 10-18-year-olds in a 4-year longitudinal study. Clinical ratings of Structured Interview potential for hostility, self-reported Minnesota Multiphasic Personality Inventory-derived hostile attitudes, and perceptions of family support were obtained at study entry and at follow-up when subjects were ages 15-21. Results showed relative stability of hostility rankings across 4 years, with males being more hostile than females. Both sexes increased in hostility over time, with the greatest increase in Ss who perceived low family support at follow-up and whose parents perceived high family support at study entry. Results are consistent with notions that early signs of hostility are risk factors for later development of coronary disease and that family environment influences development of hostility.

Adolescent↗

PubMed1993

Diet, alcohol, and physical activity as a function of smoking status in middle-aged women.

Diet, alcohol intake, and leisure-time physical activity were compared cross-sectionally in middle-aged female smokers, ex-smokers, and never smokers and were reassessed approximately 3 years later. At initial contact, there were no group differences in total caloric intake and very few differences in nutrient intake, but alcohol intake of current smokers and ex-smokers was at least 50% greater than that of never smokers, and current smokers reported less physical activity than did ex-smokers and never smokers. Prospective findings were similar: Compared with continuing smokers, ex-smokers did not change their dietary and alcohol intake but significantly increased physical activity. Thus, some adverse behaviors associated with smoking (e.g., alcohol intake) may be due to self-selection to history of smoking, whereas other behaviors (e.g., reduced physical activity) may be more directly related to smoking itself.

Age Factors↗

PubMed1993

Menopausal status influences ambulatory blood pressure levels and blood pressure changes during mental stress.

BACKGROUND: Frequent and large cardiovascular and neuroendocrine responses to psychological stress are thought to enhance an individual's risk for cardiovascular diseases. Preliminary data suggest that levels of reproductive hormones affect the magnitude of stress responses, perhaps contributing to the protective effect of ovarian hormones on premenopausal women's rates of coronary heart disease. METHODS AND RESULTS: Healthy middle-aged men and premenopausal and postmenopausal women performed a series of standardized mental and physical challenges while blood pressure, heart rate, plasma catecholamines, lipids, and lipoproteins were measured. Subjects then wore an ambulatory blood pressure monitor during two consecutive workdays. Results showed that postmenopausal women had larger mean +/- SEM stress-induced increases in systolic blood pressure (24.7 +/- 2.2 mm Hg) and diastolic blood pressure (14.3 +/- 1.0 mm Hg) compared with either premenopausal women (16.9 +/- 1.3 and 10.2 +/- 0.9 mm Hg) or men (17.7 +/- 1.5 and 10.9 +/- 1.1 mm Hg, respectively). Postmenopausal women and men had higher mean +/- SEM ambulatory diastolic blood pressure levels (75.5 +/- 3.2 and 76.4 +/- 1.8 mm Hg) than did premenopausal women (69.9 +/- 2.2 mm Hg). Large blood pressure responses during public speaking were associated with high cholesterol levels and low educational attainment. CONCLUSIONS: Menopause is associated with enhanced stress-induced cardiovascular responses and elevated ambulatory blood pressure during the workday. These effects may contribute to the risk of cardiovascular morbidity and mortality after the menopause.

Adult↗

PubMed1993

Cardiovascular reactivity to stress predicts future blood pressure status.

Cardiovascular reactivity to stress may have a pathophysiological role in neurogenic hypertension. We studied the value of measuring blood pressure change during standardized mental and physical challenges to prediction of resting blood pressure status 6.5 years later among 206 middle-aged adults and their 164 children, with the latter group originally being tested while enrolled in elementary through high school. After adjustment for age, resting blood pressure, and body mass index at study entry, as well as length of follow-up, larger systolic and diastolic blood pressure responses to a combination of mental and physical challenges were associated with higher subsequent resting diastolic blood pressure 6.5 years later among adults. Among boys, but not among girls, larger systolic and diastolic blood pressure responses to challenge were associated with higher subsequent resting blood pressure. These data suggest that people who are at high risk for elevated blood pressure might have an exaggerated stress-induced cardiovascular response at a younger age.

Adolescent↗

PubMed1993

A functionally specialized alpha-tubulin is required for oocyte meiosis and cleavage mitoses in Drosophila.

Three alpha-tubulin proteins contribute to microtubules during oogenesis and early embryogenesis in Drosophila melanogaster: alpha TUB84B, alpha TUB84D, and alpha TUB67C. alpha TUB67C is unique in two respects. It is a structurally divergent alpha-tubulin, sharing only 67% amino acid identity with the generic isotypes alpha TUB84B and alpha TUB84D, and its expression is exclusively maternal. The genetic analysis of the alpha Tub67C gene described here demonstrates that alpha TUB67C is required for nuclear division in the oocyte and early embryo. Both meiosis and cleavage-stage mitoses are severely affected by mutations that result in a substantial decrease in the ratio of alpha TUB67C/alpha TUB84B+alpha TUB84D. A large increase in this ratio, achieved by increasing the gene dosage of alpha Tub67C, has little or no effect on meiosis, but severely disrupts mitotic spindle function. Thus, both classes of alpha-tubulin isotype present in the mature oocyte, alpha TUB67C and alpha TUB84B/84D, are essential for normal spindle function in early Drosophila development. These alpha-tubulins provide the first example of tubulin isotypes known to be coexpressed in wild-type animals whose encoded variation is required for the normal function of a microtubule array.

Animals↗

PubMed1992

Environmental and familial contributions to insulin levels and change in insulin levels in middle-aged women.

OBJECTIVE: To examine familial and environmental variables associated with elevated insulin levels and changes in insulin levels in healthy, premenopausal women. METHODS: A population-based sample of 518 women (aged 42 to 50 years) completed baseline assessments of weight, cardiovascular risk factors, exercise behaviors, and glucose and insulin levels (fasting and 2 hours after a glucose load); 495 of the women were reevaluated after 3 years. RESULTS: Plasma insulin levels were related to weight, activity level, race, body fat distribution, and weight gain since age 20 years. Parental history of either diabetes or hypertension was also related to elevated insulin levels, independent of body mass index, with the highest insulin levels occurring in those women with a parental history of both diseases. Increases in plasma insulin levels over the years of follow-up were related to weight gain. CONCLUSIONS: This study suggests that importance of using family history to identify women who may have elevated insulin levels and of intervening to prevent weight gain during middle age.

Adult↗