Search PubMed⌕ Search

Biomedical subjects

S Richardson

Publications and source records attributed to S Richardson.

At least 145 records · Page 8Linked to original sources
PubMed1990

Effect of anxiety on optimism.

A quasi-experimental study was designed to investigate the possibility that people's optimism is reduced if they experience a specific form of negative affect, namely, anxiety. The level of optimism held by two groups of English students toward a range of life events was examined. Students taking examinations, the experimental group, were in an anxious state. Students who had completed their examinations, the control group, were less anxious. Those in the anxious group were less optimistic about the likelihood of both negative and positive events happening to them than were those in the control group. They were also less optimistic about the likelihood of events happening to others and of events happening to them in comparison with others. It was concluded that negative affect in general, and anxiety in particular, may have a global effect upon optimism: It may reduce optimism toward a broad range of judgments.

Adolescent↗
PubMed1990

Prognostic factors determining survival in breast cancer patients presenting with metastatic disease.

Although patients with advanced breast cancer usually die of their disease, the clinical course is highly variable. Numerous investigators have examined potential prognostic factors predicting time to recurrence for primary (localized) breast cancer. Less attention has been paid to evaluating prognostic factors in patients presenting with metastatic disease. A group of 86 women with metastatic breast cancer diagnosed between 1974 and 1984 was studied to determine the effect of certain prognostic factors on survival. Univariate analysis of these factors indicates that specific sites of recurrence, estrogen receptor (ER) status, size of the primary tumor at original diagnosis, and tumor histology; i.e., tumor differentiation, were significantly associated with predicting survival in patients presenting with metastatic disease. Poor survival, i.e., less than, or equal to, 22 months from initial presentation, is associated with a primary tumor greater than five cm., ER level less than 10 fmol/mg. of protein, lung and bone marrow recurrence, and poorly differentiated histology. Menstrual status, age, bone or lymph node site of metastases, and elapsed time between patient knowledge of symptoms and subsequent initial medical evaluation were not significant predictors of survival in patients presenting with metastatic disease.

Adult↗
PubMed1989

Relationship between vitamin E and polyunsaturated fatty acids in breast cancer. Nutritional and metabolic aspects.

Intake of vitamin E, total lipids, total cholesterol, and fatty acids were analyzed with the blood levels of vitamin E, total cholesterol, triglycerides, and the serum distribution of fatty acids in a hospital-based population of 120 patients and 109 controls. In regard to nutritional intake, the only significant differences involve saturated and monounsaturated fatty acid consumption, which is more elevated in postmenopausal patients than in postmenopausal controls. Vitamin E and total cholesterol blood levels are significantly higher in patients than in controls, where the difference is that vitamin E is independent from cholesterol level in premenopausal women only. Fatty acid serum distribution is comparable in both samples, with the exception of arachidonic acid, which is significantly lower in premenopausal patients than in premenopausal controls. Two multivariate regression analyses of the plasma vitamin E levels of patients and controls were done with menopausal status and nutrients as independent variables for the first analysis, and with menopausal status and all blood analytes for the second one. The regression coefficients for total cholesterol and triglycerides are statistically significant for both samples, whereas a positive association between vitamin E plasma level and sunflower oil consumption and between vitamin E plasma level and serum linoleic acid distribution is significant for patients only. Furthermore, the multiple regression shows that, when adjusted for analyte variables, plasma vitamin E levels are higher in premenopausal than in postmenopausal patients. In addition, plasma lipid peroxidation, evaluated by malondialdehyde measurement, is shown to be significantly lower in patients than in controls. Malondialdehyde level is associated with a significant lower odds ratio (OR) after multivariate tertile analysis (OR for the highest tertile: 0.51; 95% CI: 0.29-0.89). Together, these findings are consistent with a picture of lower lipid peroxidation in patients than in controls.

Adult↗
PubMed1989

Alcohol consumption in a case-control study of breast cancer in southern France.

The effect of alcohol consumption on breast cancer risk was investigated in a hospital-based, case-control study of 808 patients (349 cases and 459 controls) in Montpellier (France). Semi-quantified diet history including beverage consumption as well as relevant medical and personal characteristics were assessed by interview. A dose-rate relationship for total alcohol consumption was found with unadjusted odds ratios ranging from 1.8 (95% CI 1.2-2.8) for 1 to 2 drinks per week to 3.5 (95% CI 2.0-6.1) for more than 17 drinks per week, in comparison with less than 1 drink per week. Confounding by known or suspected determinants of breast cancer, smoking, use of oral contraceptives, lipid and vitamin consumption was looked into. Significant interactions were found with level of education and lipid consumption, with a higher risk for alcohol in women having had less schooling or consuming less fat. Adjustment with respect to the other risk factors did not modify the relationship. There was a significant risk increase both for wine and stronger drinks. Along with several other studies, our results give support to the hypothesis that alcohol is a risk factor in breast carcinogenesis.

Alcohol Drinking↗
PubMed1989

Photoaffinity labeling of the lumenal K+ site of the gastric (H+ + K+)-ATPase.

A photoaffinity label for the lumenal K+ site of the gastric (H+ + K+)-ATPase has been identified. Seven azido derivatives based upon the reversible K+ site inhibitor SCH 28080 were studied, one of which, m-ATIP (8-(3-azidophenylmethoxy)-1,2,3-trimethylimidazo[1,2-a] pyridinium iodide), was subsequently synthesized in radiolabeled form. In the absence of UV irradiation, m-ATIP inhibited K+ -stimulated ATPase activity in lyophilized gastric vesicles competitively with respect to K+, with a Ki value of 2.4 microM at pH 7.0. Irradiation of lyophilized gastric vesicles at pH 7.0 with [14C]m-ATIP in the presence of 0.2 mM ATP resulted in a time-dependent inactivation of ATPase activity that was associated with an incorporation of radioactivity into a 100-kDa polypeptide representing the catalytic subunit of the (H+ + K+)-ATPase. Both inactivation and incorporation were blocked in the presence of 10 mM KCl but not with 10 mM NaCl, consistent with interaction at the K+ site. The level of incorporation required to produce complete inhibition of ATPase activity was 1.9 +/- 0.2 times the number of catalytic phosphorylation sites in the same preparation. Tryptic digestion of gastric vesicle membranes, labeled with [14C]m-ATIP, failed to release the radioactivity from the membranes suggesting that the site of interaction was close to or within the membrane-spanning sections of this ion pump.

Affinity Labels↗
PubMed1989

Short-term effects of sulphur dioxide pollution on mortality in two French cities.

To assess the short-term effects of sulphur dioxide (SO2) atmospheric pollution on mortality a study was conducted in two large French cities, using daily measures of pollution and mortality. A statistically significant association between daily SO2 pollution and respiratory deaths up to 10 days later was shown in both cities for both male and female populations together in the age group 65 years and over. No coherent results were found between SO2 pollution and cardiovascular deaths, or between suspended particulates and either respiratory or cardiovascular deaths. Particular emphasis was put on the use of correct statistical procedures using time series analysis and on the comparison of the part played by SO2 or suspended particulates on mortality.

Age Factors↗
PubMed1989

Endurance fitness and blood lactate concentration during stepping exercise in untrained subjects.

The purpose of the present study was to explore the possibility that reference blood lactate concentrations, determined during stepping exercise, could be used to derive an index of endurance fitness. The traditional measure of endurance fitness, maximal oxygen uptake (VO2max) and the individual relationships between blood lactate concentration and submaximal VO2 were determined during stepping for 10 untrained males. VO2 max values were 48.7 +/- 5.1 ml.kg-1.min-1 (mean +/- sd). The time to exhaustion during stepping at 80 per cent VO2 max (38.82 +/- 17.83 min) provided an additional measure of endurance fitness. The per cent VO2 max at a blood lactate concentration of 4 mM was correlated significantly with endurance time (rho = 0.75, P less than 0.05). These results show that a submaximal step test can be used to determine oxygen uptake and per cent VO2 max at a reference blood lactate concentration. However, for this group of subjects, per cent VO2 max at a blood lactate concentration of 4 mM showed only a modest correlation with endurance.

Adult↗
PubMed1989

Assessing the significance of the correlation between two spatial processes.

Modified tests of association based on the correlation coefficient or the covariance between two spatially autocorrelated processes are presented. These tests can be used both for lattice and nonlattice data. They are based on the evaluation of an effective sample size that takes into account the spatial structure. For positively autocorrelated processes, the effective sample size is reduced. A method for evaluating this reduction via an approximation of the variance of the correlation coefficient is developed. The performance of the tests is assessed by Monte Carlo simulations. The method is illustrated by examples from geographical epidemiology.

Adult↗
PubMed1988

Two's company.

Explore the source record for details and available documents.

Employment↗
PubMed1988

Liposoluble vitamins and lipid parameters in breast cancer. A joint study in northern Italy and southern France.

The relationship between breast cancer, liposoluble vitamins, cholesterol and triglycerides was investigated by means of a hospital-based case-control study conducted at Milan (Italy) and Montpellier (France). These parameters were measured in blood samples taken from 319 cases and 344 controls. The interview included an evaluation of dietary intake of liposoluble vitamins. No difference emerged in liposoluble vitamin consumption, whereas a statistically significantly higher serum level of cholesterol and plasma level of vitamin E existed in cases compared to controls. The difference in plasma vitamin E was confirmed after adjustment for total cholesterol and triglycerides. In contrast, vitamin A variations appear to follow triglyceride trends. A multivariate analysis of the vitamin E plasma level was performed after classification of cases and controls according to quintile distribution of controls. All known risk factors plus age, serum total cholesterol and triglycerides were used as covariates. The odds ratio value for the highest quintile of plasma vitamin E is: 4.2 (1.9-9.0).

Adult↗
PubMed1988

GHRF causes biphasic stimulation of SRIF secretion from rat hypothalamic cells.

The complex interactions of the hypothalamic releasing peptides somatostatin (SRIF) and growth hormone (GH)-releasing hormone (GHRF), which regulate GH secretion, are still incompletely understood. To further scrutinize these interactions, we have studied the effects of GHRF on SRIF secretion from dispersed adult rat hypothalamic cells. Rat GHRF caused calcium- and dose-dependent stimulation of SRIF release in static 1-h incubations. SRIF release was stimulated by GHRF in a concentration range of 1-100 nM. However, the extended dose-response curve was biphasic in nature, with a significantly lower SRIF response in the presence of 1 microM GHRF vs. 100 nM GHRF. SRIF release, stimulated by another secretagogue (10 microM veratridine), was not affected by the presence or absence of 1 microM GHRF, suggesting the lack of toxic impairment of hypothalamic cell function by GHRF at this concentration. In conclusion, a biphasic stimulatory pattern of SRIF secretion in response to GHRF was observed in experiments employing dispersed rat hypothalamic cells. The biphasic SRIF response pattern to GHRF may be relevant in the physiological regulation of GH secretion.

Animals↗