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Biomedical subjects

J Ritchie

Publications and source records attributed to J Ritchie.

At least 19 recordsLinked to original sources
PubMed1992

Association of lifestyle and personality characteristics with blood pressure and hypertension: a cross-sectional study in the elderly.

The association between certain lifestyle and personality characteristics and blood pressure in the elderly was assessed in a cross-sectional study of 843 independent living 60-87 year old volunteers. They comprised 338 women and 505 men of whom 35 and 30% respectively were being treated with antihypertensive drugs. Among untreated volunteers, 28% of women and 28% of men had systolic blood pressure greater than 160 or diastolic blood pressure greater than 95. Isolated systolic hypertension was found in 20% of untreated women and 14% of untreated men. Lifestyle factors and personality characteristics associated with blood pressure were similar to those described in younger adult populations, although there were some differences related to gender and whether subjects were being treated for hypertension. Stepwise multiple regression showed that higher blood pressure was associated with greater body mass index (BMI), alcohol intake and coffee drinking and measures of irritability. Increased physical activity, and high values for measures of suspicion and extraversion were negatively related to blood pressure. Age was positively related to systolic, but not to diastolic blood pressure. The presence of hypertension was significantly associated with self-reports of raised cholesterol, diabetes or angina, as well as past history of heart failure, heart attack or stroke. Thus, in this elderly free-living population blood pressures are still significantly associated with behavioural characteristics which could be further investigated as an alternative or adjunct to antihypertensive therapy.

Aged↗
PubMed1992

Postural fall in blood pressure in the elderly in relation to drug treatment and other lifestyle factors.

In a study of 843 independent-living men and women aged between 60 and 87 in Perth, Western Australia, stepwise multiple regression, after correction for initial levels of systolic blood pressure, showed that postural fall in systolic blood pressure was positively related to alcohol intake of more than 20 ml/day, the use of sleeping tablets and higher levels of anxiety on the Spielberger state-trait scale, and negatively related to body mass index. Postural fall in blood pressure was not significantly related to treatment for hypertension, age, sex, patterns of usual physical activity, tea or coffee drinking, or the diagnosis of diabetes mellitus. This analysis is the first to examine the relationship between lifestyle factors and the magnitude of the fall in systolic blood pressure on standing after adjustment for the association between the change in a variable and its initial level. Our analysis suggests the need for further study of the possible role of lifestyle factors such as the use of sleeping tablets and alcohol in postural hypotension in the elderly.

Aged↗
PubMed1991

Neuroendocrine effects of diazepam in panic and generalized anxiety disorders.

The adrenocorticotropic hormone (ACTH), cortisol, and growth hormone responses to four consecutive, logarithmically increasing doses of intravenous diazepam compared with placebo given at 15-min intervals were examined in patients with panic disorder (n = 13), generalized anxiety disorder (n = 8), and healthy controls (n = 13). Diazepam caused dose-dependent decreases in cortisol and increases in GH and dose-independent decreases in ACTH. There were no patient-control differences, possibly due to either the small sample size of the experimental paradigm, which tested subjects in an upright, sitting position in mildly arousing circumstances.

Adrenocorticotropic Hormone↗
PubMed1990

Determination of plasma dexamethasone by chemical oxidation and electron capture negative ionization mass spectrometry.

A quantitative assay for dexamethasone in human plasma is described as based on methodology employing electron capture negative ionization mass spectrometry (ECNI/MS). The unique feature of this assay is the sample preparation involving chemical oxidation which transforms dexamethasone to a highly electrophilic species while not significantly affecting the electrophilic character of the biochemical matrix, thereby permitting selective and sensitive detection of the analyte. Optimized chemical procedures and instrumental parameters are described for the detection of oxidized dexamethasone. Finally, the newly developed methodology, based on gas chromatography/mass spectrometry (GC/MS) with ECNI, is evaluated by comparison with a conventional GC/MS assay using electron impact of an 11,17,21-tris-trimethylsilyl ether 20-enol-trimethylsilyl ether derivative of dexamethasone and with a radioimmunoassay in the analysis of pooled samples of human plasma containing widely varying concentrations of the drug as obtained from patients at different stages of the dexamethasone suppression test.

Dexamethasone↗
PubMed1988

Eating attitudes and behaviours of a sample of university students.

A sample of 213 first year psychology students at the University of Waikato (139 women, 74 men) completed a questionnaire on eating attitudes and behaviours. The women students were significantly more likely than the men to erroneously believe themselves to be overweight, to feel dissatisfied with their present weight and to go on diets. Fourteen percent of the women, but only 1% of the men scored more than 30 on the eating attitudes test, a score believed to be indicative of potential eating disorder. The social pressures which result in women's unrealistic expectations of their body size are discussed.

Adult↗
PubMed1987

Effects of gamma-interferon on the endocrine system: results from a phase I study.

Interferon causes profound biological changes when given to patients with cancer and many of these could not be predicted from in vitro or animal model systems. We documented significant changes in hormonal levels for a group of 18 patients who were participants in a Phase I gamma-interferon trial. Adrenocorticotropic hormone, cortisol, and growth hormone were all significantly elevated 2 h after treatment with gamma-interferon, with cortisol and adrenocorticotropic hormone returning to base line by 24 h. A placebo group failed to show this change, suggesting a specific interferon effect. Possible mechanisms for these findings and implications for the use of interferons are discussed.

Adrenocorticotropic Hormone↗
PubMed1987

Children's knowledge of the health risks of smoking.

One thousand, two hundred and fifty-four intermediate and secondary school students ranging in age from 10 to 16 were questioned, as part of a larger study on their knowledge of the health risks of smoking. Though they were well aware of some of the specific ill effects of smoking including its relationship to lung cancer and the danger to the fetus during pregnancy, very few (12% of girls and 14% of boys) knew that smoking causes more deaths in New Zealand than road accidents. Existing health education programmes have clearly failed to teach young people about the potentially fatal effects of smoking.

Adolescent↗
PubMed1987

Estimation of myocardial infarct size by electrocardiographic and radionuclide techniques.

The Western Washington Intravenous Streptokinase in Acute Myocardial Infarction Trial was a randomized, experimental, multicenter clinical study comparing intravenous streptokinase therapy to conventional therapy of acute myocardial infarction. Myocardial infarct size was estimated by spatial vectorcardiography in 93 patients in the treatment group and 80 patients in the control group eight weeks post MI. The estimated infarct size for the treated group was smaller: 16 +/- 10% MI vs. 20 +/- 9% MI for the control group, P = 0.01. Four independent techniques to estimate infarct size were prospectively compared within the same day: Cowan's spatial VCG; the Selvestor/Wagner QRS score; 99m technetium synchronized ejection fractions and 201-Thallium Tomography. There was strong correlation between the two ECG techniques (r = 0.88) and between the two radionuclide techniques (r = 0.77). Statistically significant correlations (P = 0.0001) were described, respectively, among the four techniques, but the correlations were not clinically strong between electrocardiographic and radionuclide techniques: IAD vs. EF, r = -0.41; IAD vs. 201-Tl, r = 0.50; QRS Score vs. EF, r = -0.49; QRS Score vs. 201-Tl, r = 0.58.

Clinical Trials as Topic↗
PubMed1986

Alterations in corticotropin-releasing factor-like immunoreactivity in discrete rat brain regions after acute and chronic stress.

Corticotropin releasing factor (CRF) may regulate endocrine, autonomic, and behavioral responses to stress. Evidence indicates that CRF-like immunoreactivity (CRF-LI) is widely distributed throughout the CNS. In this study, the distribution of CRF-LI was determined in 36 rat brain regions by combined radioimmunoassay-micropunch dissection techniques and the effect of stress on CRF-LI was investigated, using a chronic stress model that induces endocrine changes in rats similar to those seen in depressed humans. A control group of rats was handled daily. An acute stress group was subjected to 3 hr of immobilization at 4 degrees C, while a chronic stress group was exposed to unpredictable stressors. Thirty-six brain regions were microdissected by the technique of Palkovits and assayed for CRF-LI, using a specific antiserum to ovine CRF. CRF-LI was detected in most regions. In controls, the highest concentrations were found in the arcuate nucleus/median eminence, the hypothalamic paraventricular (PVN) nucleus, and the periventricular nucleus. The next highest levels were found in the raphe nuclei and dorsal vagal complex. CRF-LI was well represented in the locus coeruleus (LC); in the central, cortical, and medial amygdaloid nuclei; and in the bed nucleus of the stria terminalis. Low concentrations occurred in the hippocampus and cerebrocortical regions. Appreciable concentrations were detected in midbrain and brain stem regions. Acute stress reduced CRF-LI in the arcuate nucleus/median eminence (ME) (by 52%) and in the median preoptic (MPO) nucleus (by 32%) and doubled its concentration in the locus coeruleus.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1979

Oral health of Rhodesia African first year student teachers.

A basic oral health survey was carried out on a random sample of first year African student teachers attending four teachers' colleges in Rhodesia. The number examined and interviewed was 309. Methods and criteria used are those described in the second (1977) edition of the World Health Organization manual Oral health surveys - Basic methods. Prevalences of dental caries were 31.0% for the 142 male students and 59.5% for the 167 female students. The difference is statistically significant (P less than 0.001). Mean DMFTs were 0.74 for men and 2.02 for women. The prevalences of "intense gingivitis" were 52.8% for male students and 34.7% for female students. This difference also is significant (P less than 0.005). The major treatment requirements are for one-surface fillings and prophylaxis with oral hygiene instruction. Dental service utilization is low. Less than 10% of the sample had obtained dental care in the previous 12 months. The main reason for seeking care was pain. Self-assessments of oral health needs were not valid. The stated desire for fillings is greater than for extractions. A need has been demonstrated for dental health education aimed at the prevention of disease and the encouragement, use and demand for quality care services.

Adolescent↗