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Biomedical subjects

D Robson

Publications and source records attributed to D Robson.

At least 73 records · Page 4Linked to original sources
PubMed1984

A preliminary double-blind study of intravenous nitroglycerin in acute myocardial infarction.

A preliminary double-blind, placebo-controlled study of the effects of a 48-h intravenous infusion of nitroglycerin (NG) in 140 patients with acute myocardial infarction has been carried out. The patients were randomised to placebo or active treatment within 12 h of the onset of symptoms. Those patients treated with nitroglycerin showed a significant reduction on both days in systolic blood pressure, haemoglobin concentration, and packed cell volume. There was also a significant reduction in diamorphine usage in the first 24 h. There was a higher incidence (non-significant) of dysrhythmia in the placebo group despite an increased usage of antidysrhythmic therapy. The mortality rate in the placebo group was 13%, and 7.8% in the active treatment group, but this difference was not significant. At the 3-month follow-up, 83% of treated patients as opposed to 60% of placebo group were able to resume normal or near-normal activities. Preliminary findings suggest that intravenous NG may be useful treatment for patients with acute myocardial infarction and a larger-scale trial is warranted.

Adult↗
PubMed1983

Patterns of cancer in geographic and endogamous subdivisions of the Hutterite Brethren of Canada.

The Hutterite Brethren comprise a religious isolate and live on communal agricultural farms (colonies) in North America. In 1976 there were approximately 15,000 Canadian Brethren living in 179 colonies of the three endogamous subdivisions, the Dariusleut, Lehrerleut, and Schmiedeleut. Dariusleut and Lehrerleut colonies are located in both Alberta and Saskatchewan, and the Schmiedeleut are in Manitoba. Brethren were identified on population-based cancer registries of the three Prairie Provinces and among death registrations in the vital statistics of Alberta and Saskatchewan. The method of ascertainment was by a search for the 15 contemporary surnames and verification by address. 89 male and 91 female Brethren were identified who had cancer during the period, 1956--1975. The numbers of observed cancers were less than expected from provincial incidence rates for males and females in each province. The largest deficits were for female Brethren in Manitoba and Saskatchewan. There is a marked deficiency of cancer of the uterine cervix among female Brethren. In males there is a significant deficit of lung cancer. The Hutterite way of life contributes to a low risk for cancers of smoking-associated sites. However, there is evidence that male Brethren in Alberta may be at relatively increased risk for stomach cancer and leukemias. The site distribution patterns of cancers among the three endogamous leut are similar.

Canada↗
PubMed1982

Alcohol-induced alterations in calcium metabolism in the pregnant rat.

The effect of alcohol ingestion during pregnancy on maternal calcium metabolism was investigated by allowing pregnant rats to ingest Purina Rat Chow ad libitum along with 20% ethanol in their drinking water from day 6 to 19 of pregnancy. Ethanol constituted 50% of the caloric intake and resulted in blood levels of 98 mg/dl on day 19 of gestation. Control rats were pair-fed with rat Chow and dextrimaltose was isocalorically substituted for ethanol in the drinking water. Alcohol consumption was attended by decreased serum levels of calcium (7.3 +/- 0.5 versus 9.5 +/- 0.3 mg/dl, p less than 0.01), and phosphorus (5.7 +/- 0.5 versus 7.5 +/- 0.3 mg/dl, p less than 0.01), as well as by lowered tubular reabsorption of phosphate (88.6 +/- 4.6 versus 95.0 +/- 0.7%, p less than 0.05). The fasting urinary calcium/creatinine ratio (Ca/Cr), an index of bone resorption, was increased in the alcohol-consuming rats (0.41 +/- 0.08 versus 0.24 +/- 0.04, p less than 0.05). In contrast, alcohol administered to nonpregnant female rats for the same time period and resulting in blood levels of 129 mg/dl had no effect on serum calcium, phosphorus, tubular reabsorption of phosphate, or fasting urinary Ca/Cr. The data suggest that alcohol ingestion during pregnancy, a time of increased calcium requirement, produces biochemical changes consistent with secondary hyperparathyroidism.

Animals↗
PubMed1978

Diminishing hypotensive effect of increasing doses of pindolol in DOCA/saline hypertensive rats.

In DOCA-saline hypertensive rats, pindolol (4, 20 or 50 mg/kg orally) produced a hypotensive effect which was inversely related to dose. Following adrenal demedullation, a hypotensive response to the highest dose of pindolol was unmasked and the magnitude of the responses to lower doses was increased. The results suggest that adrenal catecholamines moderate the hypotensive effects of high doses of pindolol.

Adrenalectomy↗
PubMed1977

Studies on the cardiovascular effects of pindolol in DOCA/saline hypertensive rats.

1 A hypotensive response to orally administered pindolol in conscious normotensive and deoxycorticosterone acetate (DOCA)/saline hypertensive rats (DS-rats) is described. In DS-rats, pindolol (10-50 mug/kg) produced a dose-dependent fall in blood pressure and elevation of resting heart rate.2 The hypotensive response and tachycardia produced by oral pindolol (50 mug/kg) in DS-rats were prevented by propranolol (5 mg/kg), suggesting that pindolol's effects are mediated by beta-adrenoceptor stimulation.3 After mecamylamine (10 mg/kg), oral pindolol (50 mug/kg) produced a further fall in blood pressure in DS-rats, suggesting that its hypotensive effects are probably mediated in the peripheral vasculature.4 Pretreatment with oral pindolol (10 or 50 mug/kg) resulted in a reduction of neuronally-induced tachycardia in pithed DS-rats; neuronally-evoked pressor effects were also antagonized by pindolol (50 mug/kg, orally).5 Whereas pindolol, 50 mug/kg orally or intraperitoneally, produced a marked and progressive hypotensive response of rapid onset (20 min) in DS-rats the same dose intravenously produced a smaller response of delayed onset (80 minutes).6 In anaesthetized DS-rats, an equivalent degree of cardiac beta-adrenoceptor blockade was produced by pretreatment with pindolol, 50 mug/kg orally (2 h previously) or intravenously (1 h previously).7 After administration of pindolol, 2 mg/kg intravenously, to conscious DS-rats, the tachycardia produced by intravenous isoprenaline, 3 mug/kg, was almost abolished for the first 60 min of the study, whereas a hypotensive response to pindolol was delayed in onset (100 minutes).8 The hypotensive response and tachycardia produced by oral pindolol 50 mug/kg, in DS-rats were prevented by inhibition of metabolic enzyme activity by pretreatment with Proadifen (SKF 525-A), 80 mg/kg.9 The results suggest that pindolol's effects on blood pressure and heart rate in the conscious DS-rat are mediated by a metabolite(s) acting by stimulation of peripheral beta-adrenoceptors.

Administration, Oral↗
PubMed1976

Effect of intracerebroventricular 5,6-dihydroxytryptamine on blood pressure of spontaneously hypertensive rats.

The effects of intracerebroventricular injections of 5,6-DHT on the development and maintenance of hypertension in spontaneously hypertensive rats has been investigated. 5,6-DHT, injected into 6 week old rats, retarded the development of hypertension for at least 6 weeks; this effect was not accompanied by inhibition of the pressor response produced by stimulation of the total peripheral sympathetic outflow. 5,6-DHT, injected into 14-15 week old rats with established hypertension, produced a short-lived fall in blood pressure. These findings suggest that central 5-HT neurones are involved in the development of hypertension in spontaneously hypertensive rats.

5,6-Dihydroxytryptamine↗
PubMed1970

Positive correlation between initial pupil diameter and amplitude of miotic response to pilocarpine in rabbits and to carbachol in man.

A linear correlation between amplitude of miotic response and initial pupil diameter has been demonstrated in rabbits using various concentrations of pilocarpine HC1. The same correlation was found when published results in humans using carbachol were examined and it is likely that the correlation also applies to pilocarpine in humans. No such correlation was observed with physostigmine.

Animals↗
PubMedDate not supplied

Evidence for the involvement of alpha-adrenoceptor blockade in the antihypertensive action of diazoxide in the renal hypertensive rat.

The effects of diazoxide on the blood pressure and heart rate of conscious renal hypertensive rats have been investigated. The antihypertensive action of diazoxide has been studied in relation to the effects of diazoxide pretreatment on pressor responses to stimulation of the complete sympathetic outflow and to injections of noradrenaline, phenylephrine, angiotensin and serotonin in pithed rats. In pithed preparations, pressor responses to sympathetic nerve stimulation, and to injected noradrenaline and phenylephrine were significantly reduced by diazoxide pretreatment, at a time corresponding to maximal reduction of blood pressure in conscious animals. At this time there was no significant reduction of pressor responses to injected angiotensin or serotonin. These findings suggest a contribution of alpha-adrenoceptor blockade to the antihypertensive activity of diazoxide.

Adrenergic alpha-Antagonists↗
PubMedDate not supplied

Do any preoperative variables affect extubation time after coronary artery bypass graft surgery?

OBJECTIVE: The purpose of this study was to determine whether any preoperative variable had a significant effect on extubation time after coronary artery bypass graft surgery. DESIGN: The study design was retrospective. SETTING: The study was conducted in a cardiac center in the United Kingdom where 1700 cardiac surgical operations are performed per year. SUBJECTS: The study sample was composed of 89 patients who had coronary artery bypass graft surgery performed by the designated consultant cardiac surgeon in the first 6 months of 1998. OUTCOME MEASURES: The measures included preoperative variables (age, gender, body mass index, cardiac status, pulmonary status) and extubation time. RESULTS: Mean extubation time was found to be 4.97 hours. Left ventricular function was found to be statistically significant (P =.05) to extubation time. CONCLUSIONS: We found that cardiac status had an effect on extubation time and that this warranted further investigation. No other preoperative variable had a significant effect on extubation time, raising questions concerning the need for strict preoperative exclusion criteria.

Adult↗
PubMedDate not supplied

Long-term survival rates among patients with cancer in Saskatchewan, 1967-1986.

We calculated relative survival rates from 5 to 15 years after diagnosis for cancer cases diagnosed in Saskatchewan, Canada, between 1967 and 1986. Cancers with high 15-year relative survival (greater than 60%) included lip, melanoma among women, other male genital sites, and corpus uteri. As anticipated, relative survival rates declined with increasing length of follow-up, with the largest relative declines noted among those in the oldest age group (65+ years). Only small declines in relative survival were noted for cancers of the colon and cervix with increasing length of follow-up. Improved survival of cases diagnosed in the period 1980-1984 compared to 1970-1974 was observed for all sites combined, as well as the following sites: colon, lung, prostate, brain, ill-defined sites, non-Hodgkin's lymphoma, and lymphoid leukemia. For colorectal cancer, stage at diagnosis was a more important independent predictor of survival than age.

Adult↗