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Biomedical subjects

G E Barnes

Publications and source records attributed to G E Barnes.

At least 37 records · Page 2Linked to original sources
PubMed1981

Women in pharmacy.

The incomes, current positions, and work status of pharmacists were examined to assess whether the situation differs for males and females. Data on sex, region, age, marital status, education, and income were collected from a random sample of practicing pharmacists in six major urban centers in Canada. Women were more likely to earn less than +20,000 per year and to be employees rather than owners. Both men and women were just as likely to be managers. There is no sex difference in administrative positions for those under 30 years of age. It is at this age, when one starts moving up the professional ladder, that the sex differences emerge. It was also found that women are more likely than men to be part-time pharmacists. It is suggested that women's socialization and/or attitudinal or structural barriers at the work level account for the sex differences.

Canada↗
PubMed1979

Reliability of the maximum derivatives of left ventricular pressure and internal diameter as indices of the inotropic state of the depressed myocardium.

The effects of inotropic stimulation and increases in end-diastolic diameter, aortic pressure, left ventricular end diameter size, mean arterial pressure, and heart rate on maximum rate of change of left ventricular pressure (dP/dtmax) and diameter (dD/dtmax) were studied in eight dogs. Responses were studied in the normal conscious state, during myocardial depression due to high doses of pentobarbital or propranolol, and after bilateral cardiac sympathectomy. In all states studied, both dP/dtmax and dD/dtmax were substantially augmented by inotropic stimulation with isoprenaline and were less influenced by changes in end-diastolic diameter, mean arterial pressure and heart rate. It is concluded that both indices are highly sensitive to the contractile state of the left ventricle and relatively insensitive to haemodynamic alterations in both normal and depressed hearts.

Animals↗
PubMed1979

Autoregulation of superior mesenteric flow in fasted and fed dogs.

Pressure-flow relations in the intestinal vasculature were obtained by producing stepwise reductions of intestinal perfusion pressure with an adjustable metal clamp placed upon the descending thoracic aorta. To eliminate intervention of the baroreceptor reflex, systemic arterial pressure was maintained constant by a pressure compensation system connected to the two carotid arteries. In the fed dogs, autoregulatory vasodilatory responses to reduced perfusion pressure maintained flow within 5% of control in the 85-125 mmHg range. In 30% of the fed dogs, superior mesenteric flow actually increased as perfusion pressure was reduced in the pressure range 85-125 mmHg, indicating superregulation of flow in the intestinal vasculature. The degree of flow autoregulation in the fasted dog was less than in the fed dog. Moreover, superregulation of intestinal flow was not observed in any of the fasted animals. These data suggest an intimate link between parenchymal activity and local flow control in the small intestine.

Animals↗
PubMed1979

Regulation of cardiac output during rapid volume loading.

Interactions between heart rate (HR) and the Frank-Starling mechanism in augmenting cardiac output (CO) during acute volume loading were studied in dogs under varying conditions. In normal conscious dogs with low HRs of 70--90 beats/min, end-diastolic diameter (EDD) was maximal and CO was increased reflexly by cardioacceleration. By contrast, anesthetized open-chest dogs with high HRs ranging from 140 to 160 beats/min, responded with bradycardia and CO was adjusted solely by increasing stroke volume (SV). In anesthetized open-chest dogs with low HRs, EDD was less than maximal and increases in both HR and SV contributed to augment CO. These data show that both the cardioacceleration reflex and the Frank-Starling mechanism are important determinants of the cardiac response to elevated preload. Although the relative contribution of each control mechanism varies with initial conditions, their interplay extends the range of cardioregulation beyond that attainable by either loop operating alone.

Animals↗
PubMed1979

Solvent abuse: a review.

The literature on solvent abuse is reviewed. Methods of use, symptoms of use, and effects of long-term solvent abuse are discussed. Several surveys on solvent use are summarized. The highest prevalence of solvent abuse seems to occur in native peoples undergoing periods of cultural change. Environmental conditions which are postulated as leading to psychological vulnerability and solvent abuse include: low social assets, parental drug use, peer and sibling influence, and acculturative stress. Solvent abuse seems to provide a pharmacological way out of a stressful environment for people who feel helpless to improve their situation in other ways. Methods of intervention that have been proposed for dealing with solvent abuse are discussed. Methods of intervention thus far employed generally have not been evaluated in any systematic fashion. Suggestions for future research are provided.

Adolescent↗
PubMed1978

Effects of coronary ligation of the chromically sympathectomized dog ventricle.

The cardiac response to acute coronary occlusion was studied after chronic ventricular sympathectomy. Infarct size was measured using nitro blue tetrazolium. In 11 control dogs, 8 dogs with ventricles sympathectomized 2 wk earlier, and 5 sham-operated dogs, mean infarct size was 20.0%, 8.9%, and 20.4% of the left ventricular weight, respectively. Infarct size in sympathectomized ventricles was significantly less than in control or sham-operated hearts (P less than 0.05). Left ventricular perfusion before and after coronary occlusion was measured in 10 controls and 7 sympathectomized ventricles using tracer microspheres. Preocclusion flow values in chronically sympathectomized ventricles were approximately 30-40% less than in controls even though arterial pressure and heart rate were no different, suggesting an increased efficiency. Furthermore, after coromanary occlusion, collateral perfusions in the central and peripheral ischemic zones of the sympathectomized ventricles were 200-400% of those in nonsympathectomized ventricles. When collateral perfusion was related to the respective preocclusion flows, the difference between control and sympathectomized ventricles was even greater. Thus, chronic ventricular sympathectomy results in reduced infarct size, and this effect may be due to a reduced flow demand as well as to an increased collateral perfusion.

Animals↗
PubMed1975

Extraversion and pain.

According to Eysenck's (1957, 1960, 1967) theory of personality, extroverts are posited as having higher pain thresholds and greater pain tolerance than introverts. The evidence for these hypothesized relationships is reviewed. Findings appear inconclusive in both cases. Probability pooling (Mosteller & Bush, 1954) is therefore performed, grouping the comparable studies and carrying out overall tests of significance. Results support the hypothesized relationships between extraversion and pain threshold and between extraversion and pain tolerance. Possible reasons why certain studies failed to find these results are discussed.

Extraversion, Psychological↗
PubMed1975

Specificity of autonomic influences on cardiac responses during myocardial ischemia.

A possible role of the autonomic nervous system in the left ventricular response to acute regional myocardial ischemia was sought in conscious dogs instrumented for measurement of left ventricular pressure, internal diameter, and aortic flow. Ischemia produced by occluding the left circumflex coronary artery caused tachycardia and reduced contractility. Changes during control occlusions were compared with those during occlusion.s after beta-adrenergic blockade, parasympathetic blockade, and combined sympathetic and parasymphatetic blockade. Beta-blockade did reduce the tachycardia and slightly reduced left ventricular diameter changes in response to coronary occlusion. Results obtained in animals following surgical cardiac sympathectomy indicated reduced tachycardia and no effects on other parameters. The principal effect of parasympathetic blockade was to augment the increase in end diastolic diameter during occlusion Right atrial pacing indicated this change was due to higher initial heart rates. Combined parasympathetic and sympathetic blockade did not alter inotropic responses to coronary occlusion. Results indicated that inotropic support due to changes in activity in autonomic nerves is not increased during acute occlusion of the left circumflex coronary artery.

Animals↗