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Biomedical subjects

M Cooper

Publications and source records attributed to M Cooper.

At least 37 records · Page 2Linked to original sources
PubMed1991

Effects of neuroleptic treatment on symptoms of schizophrenia and plasma homovanillic acid concentrations.

Measurement of plasma concentrations of the dopamine metabolite, homovanillic acid, is an indirect tool to assess changes in dopamine turnover in schizophrenic patients. Plasma homovanillic acid concentrations have been reported to decrease during neuroleptic treatment, with the decrement correlating with symptomatic improvement in symptoms of schizophrenia. The present study tested the hypothesis that neuroleptic drugs decrease plasma homovanillic acid concentrations in those schizophrenic patients who improve with administration of neuroleptic drugs but not in patients who fail to display a treatment response. Twenty schizophrenic men who remained drug free for at least 2 weeks were treated with 20 mg/d of haloperidol for 5 weeks. Symptoms and plasma homovanillic acid concentrations were assessed on the last drug-free day and weekly for 5 weeks. Mean plasma homovanillic acid concentrations decreased in the group of patients who responded to neuroleptic treatment and did not change in the group of patients who did not improve. These findings suggest that there may be a qualitative distinction between responders and nonresponders to dopamine antagonists.

Administration, Oral↗
PubMed1991

The effect of aldose reductase inhibitors on glomerular prostaglandin production and urinary albumin excretion in experimental diabetes mellitus.

The effect of two structurally unrelated aldose reductase inhibitors, sorbinil and ponalrestat, on glomerular prostaglandin production and urinary albumin excretion was investigated in rats with diabetes induced by streptozotocin. It was found that both aldose reductase inhibitors, when administered from the time of induction of the diabetes, significantly decreased the raised urinary albumin excretion in the diabetic rats, although it remained elevated compared with non-diabetic rats. Glomerular prostaglandin E and 6-keto-prostaglandin F1 alpha production was significantly increased in glomeruli obtained from the diabetic rats. Inhibition of aldose reductase caused a reduction in the raised glomerular prostaglandin production, although this remained above that observed in the non-diabetic rats. Subsequent experiments were performed to determine whether the effects of the aldose reductase inhibitors could be explained by effects on glomerular filtration rate. It was found that ponalrestat, at a dose which markedly reduced urinary albumin excretion, did not significantly affect glomerular filtration rate in non-diabetic rats, rats with untreated streptozotocin-induced diabetes and rats with diabetes partially treated with low dose insulin. Glomerular sorbitol concentrations were significantly elevated in untreated diabetic rats as early as two weeks after the induction of diabetes. It is concluded that the administration of aldose reductase inhibitors from the time of induction of diabetes significantly reduces glomerular prostaglandin production and urinary albumin excretion. The latter effect is not due to an effect on glomerular filtration rate. Increased polyol pathway activity may account in part for the increased glomerular prostaglandin production and urinary albumin excretion in early experimental diabetes.

6-Ketoprostaglandin F1 alpha↗
PubMed1991

Size and frequency characteristics of alpha beta and gamma delta T cells in the spleens of normal and cyclophosphamide-suppressed virus-infected chickens.

The characteristics of avian lymphocytes expressing surface CD8 (CT8) and T cell receptor (TCR) glycoproteins have been monitored by two-color flow microfluorimetry. Exposure of 1-month-old birds to a lethal influenza A virus, which is known to be lympholytic, significantly decreased the frequency of both the alpha beta TCR2+CT8+ and gamma delta TCR1+CT8- subsets in spleen. However, all categories of T cells showed evidence of greater mean cell size, indicating that they are responding. Inoculation of baby chicks with fowl pox virus induced a response more typical of specific immunity in the TCR2+CT8+ set, in that the lymphocytes increased in both frequency and mean cell size. Greater numbers of lymphoblasts were also found for the TCR2+CT8-, TCR1+CT8+, and TCR1+CT8- subsets, but the total cell counts for the minority TCR1+CT8- cells in spleen were consistently decreased. Immunosuppression with cyclophosphamide prior to infection eliminated 90% of the white blood cells from spleen, with the greatest effect being on the TCR1+ populations. The CT8+ alpha beta T cell response in chick spleen following exposure to a poxvirus is thus comparable to the situation observed for this subset of lymphocytes in mice infected with other viruses. However, although the gamma delta T cells increase in size, their frequency in spleen either does not change (CT8+) or is significantly decreased (CT8-).

Animals↗
PubMed1991

A population survey of cardiovascular disease in elderly people: design, methods and prevalence results.

A cross-sectional survey of an age- and sex-stratified random sample of the elderly population living in Southampton was undertaken with the object of measuring the frequency of cardiovascular disease by questionnaire and examination, and assessing cardiac anatomy and physiological function by noninvasive methods. The response rate was 64% and 259 men and women aged between 65 and 95 years were interviewed and examined and had a twelve-lead ECG and chest radiograph. Forty per cent of men and 47% of women reported a diagnosis of one or more cardiovascular diseases, of which high blood pressure 33%, coronary heart disease 14% (angina pectoris 11% and myocardial infarction 8%), peripheral arterial disease of the lower limbs 7%, and cerebrovascular disease 6% occurred most frequently. With the exception of high blood pressure, which women reported more frequently than men (40% vs 27%), the prevalence of these diagnoses by sex was similar. The self-administered WHO questionnaires gave point prevalence estimates for angina pectoris of 13%, possible myocardial infarction 7% and intermittent claudication 5%, which were similar to reported prevalences of these diseases, although disagreement in the classification of individuals for each disease was common. When comparing the WHO chest pain questionnaire with the doctors' independent diagnosis of angina pectoris in this population, the sensitivity of the WHO questionnaire was 79%, with a specificity of 98% and a predictive value of 88%. For each sex the sensitivity of the WHO chest pain questionnaire was similar but specificity and predictive value were both lower for women.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1991

Changes in vitamin and mineral intakes and serum concentrations among free-living men on cholesterol-lowering diets: the Dietary Alternatives Study.

Nutritional adequacy of diets with 18-30% of calories from fat was investigated in men with elevated serum cholesterol (n = 396) at the end of diet classes and 1 and 2 y later. On 4-d food records, intakes of vitamin A, beta-carotene, folate, vitamin C, magnesium, vitamin B-6, iron, thiamin, and riboflavin increased from baseline whereas niacin, selenium, vitamin E, and zinc decreased. Median zinc intake, 80% of the recommended dietary allowance (RDA) at baseline, decreased to approximately 75% of the RDA, most markedly when intakes of meat, fish, and poultry were limited to 85 g/d. Nutrient densities generally increased. Of the serum nutrients measured, median beta-carotene and vitamin C increased, whereas vitamin B-6, iron, and zinc were unchanged. Below-normal values were fewer for vitamin C and magnesium. Diets similar to the National Cholesterol Education Program Step-Two Diet [less than 7% saturated fatty acids, less than 200 mg cholesterol/d] appeared to provide increased levels of most micronutrients both short and long term to men receiving comprehensive dietary counseling.

Ascorbic Acid↗
PubMed1991

Influence of soluble haemagglutinins on adherence of Helicobacter pylori to HEp-2 cells.

In a study of six laboratory strains of Helicobacter pylori, two different modes of bacterial adherence to HEp-2 cells were found. Electronmicroscopy revealed that strains known to possess soluble haemagglutinin adhered intimately to the cell surfaces, with cupping of the plasma membrane and coalescence of glycocalyces at sites of attachment. Strains of H. pylori without soluble haemagglutinin also attached, but did not induce membrane cupping or show glycocalyx fusion. Light microscopy did not distinguish between these patterns of adherence. Bacterial attachment was unaffected by pre-treatment of HEp-2 cells with neuraminidase. Exposure of the bacteria to trypsin or to colloidal bismuth subcitrate (CBS) before being added to HEp-2 cells markedly impaired bacterial adherence. This effect of CBS may contribute to the known efficacy of bismuth therapy in patients with H. pylori-related gastritis.

Bacterial Adhesion↗
PubMed1991

Norplant.

Explore the source record for details and available documents.

Drug Implants↗
PubMed1991

Pharmacokinetics and tissue penetration of tazobactam administered alone and with piperacillin.

The pharmacokinetics of tazobactam (500 mg) administered intravenously alone were compared with the pharmacokinetics of tazobactam coadministered with piperacillin (4 g), and the penetration into an inflammatory exudate in six healthy males was studied. Piperacillin influenced the pharmacokinetics of tazobactam. The mean levels of tazobactam in plasma at 4 h were 0.6 microgram/ml when it was given alone and 1.2 micrograms/ml when it was given with piperacillin (P = 0.0003). The mean total clearances of tazobactam were 203.5 and 134.2 ml/min (P = 0.035) when it was given alone and with piperacillin, respectively There were no significant differences in the elimination half lives, areas under the concentration-time curve from 0 h to infinity, or volumes of distribution. Inflammatory exudate penetration was rapid, and the mean maximum levels of tazobactam attained were 6.4 and 11.3 micrograms/ml when it was given alone or with piperacillin, respectively (P less than 0.06). The mean percent penetration of tazobactam and the area under the concentration-time curve from 0 h to infinity in inflammatory exudate were greater when tazobactam was given with piperacillin. The mean 24-h urinary recoveries of tazobactam were 63.7% +/- 7.9% when it was given alone and 56.8% +/- 2.7% when it was given with piperacillin. The explanation for the differences in the pharmacokinetics of tazobactam when it was administered alone compared with those when it was given with piperacillin was unclear.

Adult↗
PubMed1991

Double-masked trial of topical acyclovir and steroids in the treatment of herpes zoster ocular inflammation.

Ninety seven new patients with ophthalmic zoster were randomly allocated to three topical treatment groups: acyclovir (ACV) ointment and placebo drops (AP), placebo ointment with steroid drops (PS), and acyclovir ointment with steroid drops (AS). The dosage administered was determined by the score of the ocular inflammation. Follow-up was for at least one year. The results showed that topical ACV alone is insufficient for severe ocular inflammation but is not inclined to lead to recurrences in milder cases. Topical steroid alone is effective but tends to necessitate prolonged treatment. Combined steroid and ACV is questionably better than steroid alone and causes marginally fewer rebound inflammations.

Acyclovir↗
PubMed1991

Halothane in children with chronic liver disease.

Exacerbation of pre-existing liver disease after halothane anaesthesia has been reported in adult patients. A prospective study was performed in 38 children with biopsy-proven liver disease to assess the effect of surgery and halothane anaesthesia on liver function. Plasma liver enzyme levels were measured immediately preoperatively and again four to eight days after surgery and halothane anaesthesia. Minor elevations of both AST and ALT occurred in four patients but this was not associated with a clinical deterioration in the patients' postoperative recovery. In the children studied pre-existing liver disease did not predispose to a deterioration of liver function following surgery and halothane anaesthesia.

Adolescent↗
PubMed1991

Retardation by aminoguanidine of development of albuminuria, mesangial expansion, and tissue fluorescence in streptozocin-induced diabetic rat.

This study evaluated the relationship between the development of fluorescence related to advanced glycosylation end products (AGEs) in the kidney and experimental diabetic nephropathy over a 32-wk period. Control, untreated diabetic, and aminoguanidine-treated diabetic rats were followed for 32 wk with eight weekly measurements of urinary albumin excretion. After 32 wk, collagen-related fluorescence in aorta and kidney (whole kidney, isolated glomeruli, and renal tubules) and glomerular ultrastructure were evaluated. Diabetes was associated with a significant increase in collagen-related fluorescence in the aorta and kidney. Aminoguanidine prevented the increases in collagen-related fluorescence in aorta, isolated glomeruli, and renal tubules but not in whole kidney. Diabetes was associated with increased albuminuria, fractional mesangial volume, and glomerular basement membrane (GBM) thickness. Aminoguanidine attenuated the rise in albuminuria and prevented mesangial expansion without influencing GBM thickness in diabetic rats. The concomitant changes in collagen-related fluorescence, albuminuria, and mesangial expansion with aminoguanidine therapy are consistent with the hypothesis that AGEs may play a role in the development of diabetic nephropathy.

Albuminuria↗
PubMed1991

Effects of diazepam on cerebral metabolism and mood in normal volunteers.

The effects of diazepam on regional cerebral metabolism were examined in eight healthy volunteers using positron emission tomography with 18-fluorodeoxyglucose as the tracer. Each subject was tested three times, at 1-week intervals, with placebo, a low oral dose of diazepam (0.07 mg/kg), and a moderate dose of diazepam (0.14 mg/kg). Subjects completed mood questionnaires before and at regular intervals after taking the drug, and performed a vigilance task during the 60-minute period of tracer uptake. The effects of the drug on cerebral metabolism were examined alone and in relation to the subjective and behavioral effects of the drug. Both doses of diazepam decreased global (whole brain) metabolic rate but did not affect specific regions differentially. Subjects experienced sedative like effects during all three scans (placebo as well as drug). Compared to placebo, both doses of diazepam decreased anxiety, and neither dose produced significant impairment of task performance. Neither the subjective nor behavioral drug effects were correlated with the changes in metabolic rate. Thus, diazepam decreased whole brain metabolic rate at doses that produced only modest subjective or behavioral effects. The changes in metabolic rate were not clearly related to other observable drug effects.

Adult↗