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Biomedical subjects

B Cox

Publications and source records attributed to B Cox.

At least 73 records · Page 4Linked to original sources
PubMed1998

Cessation of gonadotropin-releasing hormone agonist therapy combined with high-dose gonadotropin stimulation yields favorable pregnancy results in low responders.

OBJECTIVE: To evaluate the pregnancy results of an ovarian hyperstimulation protocol for IVF-ET that combines GnRH agonist down-regulation, cessation of GnRH agonist therapy with the onset of menstruation, and high-dose gonadotropin administration in low responders. DESIGN: Prospective analysis. SETTING: Academic IVF program. PATIENT(S): One hundred eighty-two low responders undergoing 224 IVF-ET cycles. INTERVENTION(S): Down-regulation was obtained with the administration of leuprolide acetate beginning in the midluteal phase and ending with the onset of menses. Daily administration of 6 ampules of FSH alone or in combination with hMG was initiated on cycle day 3. MAIN OUTCOME MEASURE(S): Stimulation characteristics and pregnancy rates (PRs) were compared between fresh cycles in which pure FSH alone was used and 35 cycles in which a combination of FSH and hMG was administered. RESULT(S): The clinical PR per transfer, the ongoing PR per transfer, and the implantation rate were 32%, 24%, and 9%, respectively. No differences were noted between cycles in which pure FSH alone was used in comparison with cycles in which a combination of FSH and hMG was administered. CONCLUSION(S): Short-term ovarian suppression begun in the luteal phase and discontinued with the onset of menses followed by high-dose stimulation with gonadotropins yields favorable pregnancy results in low responders.

Adult↗
PubMed1998

Role of neuropeptide Y in cold stress-induced hypertension.

Chronic cold stress (4 degrees C) produced a sustained increase in mean arterial pressure in both normotensive and borderline hypertensive rats (BHR). The high blood pressure in BHRs was significantly reversed by a neuropeptide Y (NPY) Y1 receptor antagonist suggesting that NPY is involved in mediating stress-induced hypertension. Corresponding increases in adrenal NPY messenger RNA and NPY immunoreactivity were found during the stress; furthermore, chronic cold stress also potentiated the pressor response of rats to a subsequent acute stress test in which NPY has been shown to play a role. These results suggest that chronic cold stress-induced hypertension is mediated by elevated NPY release and vascular tone as a result of increased NPY gene expression and storage.

Adrenal Glands↗
PubMed1998

The effect of a low-fat, high-carbohydrate diet on serum high density lipoprotein cholesterol and triglyceride.

OBJECTIVE: To determine whether substituting carbohydrate for saturated fat has any adverse effects on serum high density lipoprotein (HDL) cholesterol and triglycerides in free-living individuals. DESIGN: Randomised crossover trial. SETTING: General community. SUBJECTS: Volunteer sample of 38 healthy free-living men with mean (s.d.) age 37 (7) y, moderately elevated serum total cholesterol 5.51 (0.93) mmol/l and body mass index 26.0 (3.6) kg/m2. INTERVENTIONS: Participants completed two six week experimental periods during which they consumed either a traditional Western diet (36%, 18%, and 43% energy from total, saturated, and carbohydrate, respectively) or a low-saturated fat high-carbohydrate diet (22%, 6% and 59% energy from total, saturated, and carbohydrate, respectively). Dietary principles were reinforced regularly, but food choices were self-selected during each experimental period. MAIN OUTCOME MEASURES: Serum lipids, body weight and plasma fatty acids. RESULTS: Reported energy and nutrient intakes, plasma fatty acids, and a drop in weight from 79.1 (12.5) kg on the Western diet to 77.6 (12.0) kg on the high-carbohydrate diet (P < 0.001) confirmed a high level of compliance with experimental diets. Total and low density lipoprotein (LDL) cholesterol fell from 5.52 (1.04) mmol/l and 3.64 (0.88) mmol/l, respectively on the Western diet to 4.76 (1.10) mmol/l and 2.97 (0.94) mmol/l on the high-carbohydrate diet (P < 0.001). HDL cholesterol fell from 1.21 (0.27) mmol/l on the Western diet to 1.07 (0.23) mmol/l on the high-carbohydrate diet (P = 0.057), but the LDL:HDL cholesterol ratio improved from 3.17 (1.05) on the Western diet to 2.88 (0.97) on the high-carbohydrate diet (P = 0.004). Fasting triglyceride levels were unchanged throughout the study. CONCLUSIONS: Replacement of saturated fat with carbohydrate from grains, vegetables, legumes, and fruit reduces total and LDL cholesterol with only a minor effect on HDL cholesterol and triglyceride. It seems that when free living individuals change to a fibre rich high-carbohydrate diet appropriate food choices lead to a modest weight reduction. This may explain why the marked elevation of triglyceride and reduction of HDL cholesterol observed on strictly controlled high-carbohydrate diets may not occur when such diets are followed in practice.

Adult↗
PubMed1997

Comparison of the site distribution of melanoma in New Zealand and Canada.

A comparison of the site distribution of cutaneous malignant melanoma in New Zealand and Canada was performed. This series deals with 41,331 incident cases registered between 1968 and 1990 and is the largest to date to evaluate the influence of age and gender on the site distribution of melanoma. Site-specific, age-standardized rates per unit surface area and relative tumour density were assessed by gender and country and differences compared with statistical techniques adapted to this context. The age-standardized rates for all sites were higher in New Zealand than in Canada, the ratio being 3.2 for men and 3.8 for women. Occurrence of melanoma was denser for chronically than intermittently exposed sites in both New Zealand and Canada. The highest incidence rate per unit area was for the ears in men which was more than 5 times the rate for the entire body in each country. For each gender, melanomas were relatively commoner on the trunk and the face in Canada, and on the lower limbs in New Zealand. The variations in the site distribution were similar in each country and consistent with the effect of differential patterns of sun exposure between genders. Our results show that the levels of risk of melanoma between phenotypically comparable populations exposed to different amount of UV radiation vary in a site-specific manner, especially for intermittently exposed sites. This suggests that both environmental conditions and lifestyle factors influence the site distribution of melanoma in these two populations.

Canada↗
PubMed1997

A prospective study of Waddell signs in patients with chronic low back pain. When they may not be predictive.

STUDY DESIGN: Analysis of the treatment-outcome predictive power of Waddell signs by evaluating them before and after functional restoration, with assessment of 1-year socioeconomic outcomes. OBJECTIVE: To evaluate the presence of Waddell nonorganic signs in a group of patients with chronic low back pain presenting for functional restoration, and to determine whether they were predictive of treatment success of failure. SUMMARY OF BACKGROUND DATA: Waddell has described "nonorganic" physical signs in patients with chronic low back pain indicative of somatization. Other researchers have correlated high Waddell scores with psychosocial barriers that required additional consultation, and have suggested that diminution of a Waddell score during physical rehabilitation is predictive of subsequent therapeutic success. METHODS: Total positive Waddell signs score and individual sign scores were assessed at initial presentation for functional restoration treatment and at discharge in a group of 50 patients with chronic low back pain (average length of disability = 17.9 months; average age = 38.5 years). Patients were then tracked and assessed with a 1-year follow-up structured interview to evaluate outcome variables such as return to work, work retention, re-injury rate, health utilization, and subsequent surgery. RESULTS: Statistical analyses of these data revealed no significant associations between Waddell total positive score or changes in score and therapeutic success as measured by any of the behavioral outcomes such as return to work. Also, no predictive value was found for the individual positive signs of their changes and therapeutic success. CONCLUSIONS: Although positive Waddell signs have been found to be predictive in patients with short-term chronic low back pain, the current results suggest that, in patients who have longer duration of pain and who undergo a comprehensive functional restoration program, these signs are not significantly prognostic. Because functional restoration is an interdiscipilinary approach that effectively manages somatization complaints in a consistent manner by all treatment personnel, such complaints do not create any major barriers to recovery. Therefore, although Waddell signs may be predictive of treatment outcome in less intensive rehabilitation programs, they do not provide any predictive power in a comprehensive functional restoration program, which has a basic goal of managing barriers to recovery in a clinically efficacious manner.

Adult↗
PubMed1997

Health care costs of obesity in New Zealand.

OBJECTIVE: To estimate the costs of health care that are attributable to obesity in New Zealand. METHODS: The 1991 health care costs of non-insulin dependent diabetes, coronary heart disease, hypertension, gallstone disease, post-menopausal breast cancer and colon cancer were estimated and multiplied by the population attributable factor for obesity for each condition. The relative risk estimates were taken from the literature, the obesity prevalence from a 1990 New Zealand survey, and the costs and volumes of services were taken from a variety of sources and covered hospital (inpatient and outpatient) services, general practitioner consultations, pharmaceuticals, laboratory tests and ambulance services. Calculations were conservative and net of goods and services tax. RESULTS: A conservative estimate of the health care costs attributable to obesity for the six conditions was NZ$135 million. This represents about 2.5% of total health care costs which is similar to analyses from other countries. CONCLUSIONS: The health care costs of obesity as estimated are considerable. However, the total cost of overfatness to the New Zealand population is far greater than this because lesser degrees of overfatness, the health care costs of other obesity-related conditions such as arthritis, the costs to individuals of weight-loss programs and the indirect and intangible costs were not included in the analysis. A substantial and wide-ranging public health effort is needed to turn around the increasing prevalence and costs of obesity.

Adult↗
PubMed1997

Variation in the effectiveness of breast screening by year of follow-up.

This meta-analysis assesses the effectiveness of breast screening by year from the start of screening for women aged 40-49 at study entry. Data from previous randomized controlled trials on breast cancer screening were combined, and cumulative and yearly breast cancer mortality rates and relative risks (RRs) were calculated for women offered screening compared to those not offered screening. At 7 years of follow-up, no reduction in breast cancer mortality from screening starting at ages 40-49 was found. At 10 years of follow-up, a nonsignificant reduction in breast cancer mortality was seen for women aged 40-49 at entry (RR = 0.93; 95% CI: 0.77-1.11). A nonsignificant excess of breast cancer mortality in those offered screening aged 40-49 was observed during the early years of follow-up in several trials. While the favorable effect of screening was observed within the first 5 years of study entry for women aged 50 or more, no similar effect was seen for women aged 40-49. The delayed effect for the 40-49 cohort may be attributable to 1) a biological difference in the effects of screening, which may be related to the onset of menopause, and 2) screening that occurred when women were aged 50 or more rather than before that age.

Adult↗
PubMed1997

The effect of measurement error on the determination of Helicobacter pylori prevalence.

We assessed the effect of serum-based antibody tests on the epidemiology of Helicobacter pylori infection. We took crude population prevalences of H. Pylori infection from existing publications in which antibody-based tests were used to determine prevalence. We then calculated 95% confidence intervals that included terms for study size, sensitivity, specificity, and, where possible, the sample size used to determine the validity of the antibody test. Specificity had a greater effect than sensitivity on the overestimation of most population-based estimates of H. pylori prevalence. The attributes of some antibody-based tests imply that no matter how large the study size, an accurate estimate of prevalence could not have been obtained.

Adolescent↗
PubMed1997

Prediction of suicide intent in aboriginal and non-aboriginal adolescent inpatients: a research note.

The relationship among depressive symptoms, anxiety, hopelessness, and suicidal intent was explored in a group of 77 adolescents who had been hospitalized after attempting suicide. Regression analyses indicated that hopelessness was the only significant predictor of suicide intent in Caucasian patients, and depressed mood was the only significant predictor in the Aboriginal group. Clinicians should be aware that measures of hopelessness may be of limited value in assessing suicidal risk in Aboriginal adolescents.

Adolescent↗
PubMed1996

The squalestatins: inhibitors of squalene synthase. Enzyme inhibitory activities and in vivo evaluation of C3-modified analogues.

Squalestatin analogues modified at C3 were prepared and evaluated for their ability to inhibit rat liver microsomal squalene synthase in vitro. While the 4,6-dimethyloctenoate ester group at C6 was maintained, a number of modifications to the C3 carboxylic acid were well tolerated. However, in the absence of the C6 ester group, similar modifications to the C3 carboxyl group caused loss of activity. Selected compounds were evaluated for their ability to inhibit cholesterol biosynthesis in vivo in rats 1 and 6 h postadministration. Analogues of squalestatin 1 (S1) modified at C3 were found to possess a shorter duration of effect in vivo which is reflected in their substantially reduced ability to lower serum cholesterol levels in marmosets. Significant cholesterol lowering (up to 62%) for the C3 hydroxymethyl analogue 1b was observed only when this compound was dosed three times a day for 3 days.

Animals↗