PubMed Health⌕ Search

Biomedical subjects

T E Nightingale

Publications and source records attributed to T E Nightingale.

14 recordsLinked to original sources
PubMed1992

Social stress and atherosclerosis in roosters.

1. Socially stressed roosters fed either plain mash or an atherogenic diet had a greater incidence and severity of aortic atherogenesis than similarly fed non-stressed birds. 2. Results demonstrated a significant atherogenic effect of stress in chickens even in the absence of hyperlipidaemia. 3. Lack of appreciable differences in plasma lipids between stressed and non-stressed birds suggested that the atherogenic effects of stress may be attributable to neuroendocrine responses. 4. Levels of HDLc of plain mash groups were significantly higher than in the atherogenic fed groups. 5. Haemodynamic data showed no treatment-related differences.

Animals↗
PubMed1982

Effect of valium (diazepam) on experimental atherosclerosis in roosters.

The development of aortic and coronary atherosclerotic plaques were investigated in roosters fed an atherogenic diet with and without the addition of Valium (0.2 mg/kg twice daily) over a period of 5 months, as a step toward understanding the role of emotional factors in atherogenesis. Plasma levels of cholesterol and triglycerides, hemodynamic parameters, and body weight were measured. There was a progressive, and quantitatively similar, body weight gain in all birds. In addition, there were no significant differences in values for blood pressure, cardiac output, and heart rate between the various experimental groups. Conversely, birds receiving the atherogenic diet, as well as those receiving the atherogenic diet along with Valium, exhibited a marked hypercholesterolemia which reached a peak of 600 mg/dl in 4-6 weeks, before decreasing to between 200 and 300 mg/dl by the 10th week. Plasma triglyceride levels followed a qualitatively similar pattern as plasma cholesterol. Those birds fed an atherogenic diet alone developed atherosclerotic lesions on the aortic surface which was more pronounced on the abdominal than the thoracic aorta. Aortas from birds given Valium along with the atherogenic diet were completely free of lesions despite the fact that plasma cholesterol and triglyceride levels were not significantly different in the two groups. Histological sections of coronary arteries showed severe lesions in 4 out of 7 birds which were fed the atherogenic diet alone, whereas the birds given Valium along with the atherogenic diet had only an occasional slight lipid deposit. It was concluded that Valium provides some protection against the development of atherosclerosis in roosters fed an atherogenic diet.

Animals↗
PubMed1981

Comparison of brachial venous and mixed blood gas tensions and pH values in the chicken.

Differences in blood gas tensions and pH between brachial venous blood (BVB) and mixed venous blood obtained from the pulmonary artery (PAB) were compared in anesthetized male White Leghorn chickens to determine if BVB as obtained in routine venipuncture cold be used to estimate mixed venous values of pO2, pCO2, and pH. When paired samples were compared over the range of 25 to 68 mm Hg, brachial pO2 was 5.7 mm Hg higher (P less than .001) than PAB pO2. Brachial pCO2 was 4.25 mm Hg higher (P less than .001) than PAB pCO2 over the range of 17 to 56 mm Hg. Brachial pH was .066 units lower (p less than .001) than comparable values for PAB over the range of 7.2-7.6 pH units. Regression equations are given for estimating mixed venous blood gas tensions and pH values from blood samples taken from the brachial vein.

Animals↗
PubMed1980

Long-term effects of diazepam on plasma lipids and atheroma in roosters fed in atherogenic diet.

Long-term effects of diazepam on plasma lipids and atheroma in roosters fed an atherogenic diet have been studied. Our data indicate that long-term administration (8 months) of diazepam (Valium) 0.2 mg/kg orally lowered the plasma cholesterol level when compared to the atherogenic group, but this was not statistically significant (P greater than 0.05). However, at the dose of 0.4 mg/kg of Valium the plasma cholesterol was significantly lowered when compared to the controls on an atherogenic diet (P less than 0.05). Both doses of Valium significantly decreased the incidence and severity of lesions on the endothelial surface of the aorta and coronary artery in roosters fed an atherogenic diet. No changes in plasma triglyceride values were noted. Administration of 0.4 mg/kg of Valium to birds receiving the atherogenic diet produced a small but significant increase of mean, systolic and diastolic blood pressures as compared to the birds receiving an atherogenic diet but no Valium. A similar increase in blood pressure was also noted in the control group on plain mash diet receiving 0.2 mg/kg of Valium. Microscopic examination of the coronary arteries showed that birds on an atherogenic regimen receiving Valium had less atherosclerosis than those not receiving Valium.

Animals↗
PubMed1977

Comparison of Cardiopulmonary Parameters in awake and anesthetized chickens.

Steady state cardiovascular and respiratory parameters in adult male chickens while they were awake and after anesthetization with a mixture of chloral hydrate, magnesium sulfate, and pentobarbital were compared. Blood pressure (BP), heart rate (HR), cardiac output (CO), stroke volume (SV), peripheral resistance (TPR), tidal volume (VT), respiratory rate (RR), minute ventilation (V), end-experatory carbon dioxide partial pressure (PACO2), and arterial blood gases and pH were measured simultaneously on birds spontaneously breathing air. Anesthetization resulted in increased HR and RR and decreased BP, CO, TPR, VT, PACO2, and blood gas tension. The data indicate a depression of cardiovascular function but no change in total ventilation although the relative contributions of VT and RR were changed. Anesthetization increased variability in SV although the other parameters were maintained in a steady-state condition over a 2-h period.

Anesthesia↗
PubMed1976

Functional significance of thoracic vagal branches in the chicken.

One minute electrical stimulation was used to excite the right and left cervical vagi as well as specific points on, or branches of, the left thoracic vagus. Respiratory, heart rate and blood pressure responses were observed with the nerves intact and cut. Stimulation of either intact cervical vagus produced apnea, bradycardia and blood pressure depression. Stimulation of the cut ends after nerve section demonstrated that the heart rate and blood pressure effects were efferent and the respiratory change was afferent. No responses were observed due to stimulation of the vagus caudal to the lungs. Stimulation of cardiac branches reduced heart rate and blood pressure but did not produce significant respiratory effects. Middle and anterior pulmonary branches were found to contribute only to respiratory changes through afferent nerves. Sudden, sustained reduction of CO2 in the airways produced immediate, sustained apnea. The data suggest that CO2 sensitive thoracic receptors important in regulation of respiration are confined primarily to the lungs and that these receptors play no direct role in cardiovascular function.

Animals↗
PubMed1976

Acute isovolemic anemia in anesthetized chickens.

Acute isovolemic anemia was produced in anesthetized chickens by serial exchanges of 6% dextran 70 equal to 1% of body weight to quantitate cardiovascular and metabolic parameters. When hematocrit (Hct) and hemoglobin (Hb) levels were reduced by 50% (from 33.3 to 16.3 vol %, and from 10.3 to 5.4 g/100 g, respectively, P less than 0.001), tissue oxygen delivery was maintained by increases in cardiac output (CO), stroke volume (SV), oxygen extraction, and reduced total peripheral resistance (TPR). Heart rate, right atrial pressure, and oxygen consumption (Vo2) were unchanged. Further reductions in Hct and Hb (to 10.8 vol % and 3.7 g/100 g, respectively), were accompanied by cardiovascular failure, as evidenced by falling CO, SV, tissue oxygen delivery, and Vo2. Relative apparent viscosity determinations on the exchanged blood-dextran mixtures indicated that large viscosity changes occurred with the first exchange whereas subsequent exchanges had small incremental viscosity changes. These data indicate that in acutely anemic chickens, oxygen transport capacity was maintained by increased cardiac output and decreased peripheral resistance, unless the severity of the anemia resulted in cardiovascular failure.

Acute Disease↗
PubMedDate not supplied

Pancreatic elastase activation as a possible indicator of the relative hazard of different cigarettes.

Levels of elastase activity in homogenates of pancreas from beagle dogs exposed to cigarette smoke on a daily basis for 600 d were previously reported. Elastase activity in pancreatic homogenates from animals exposed to smoke from high-nicotine cigarettes was significantly greater than in sham-exposed controls or in animals smoking low-nicotine cigarettes. In the study described here, dogs were exposed on an acute basis to smoke from high-nicotine and from nicotine-free cigarettes. Anesthetized animals were prepared by laparotomy, duodenotomy, and pancreatic duct cannulation. Pancreatic fluid was collected and preexposure elastase levels were determined. Samples were then taken during exposure to smoke from cigarettes of both types. There was no measurable elastase activity in the baseline samples. Similarly, no activity was found in fluids collected before and during exposure to smoke from nicotine-free cigarettes. Enzyme activity was detected, however, in samples collected during exposure to smoke from high-nicotine cigarettes once blood levels of nicotine reached 50-70 ng/ml. The results suggest that cigarette smoke may provoke activation of elastase and indicate the need for further study of any association of cigarette smoking with pancreatic disease.

Animals↗