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Biomedical subjects

J N Lucke

Publications and source records attributed to J N Lucke.

At least 37 records · Page 2Linked to original sources
PubMed1980

Further studies on the metabolic effects of long distance riding: Golden Horseshoe Ride 1979.

Blood samples were taken before and immediately after 80 km and 40 km rides held on consecutive days and analysed for haematocrit, blood glucose and lactate, plasma sodium, potassium, calcium, albumin, free fatty acids (FFA), glycerol, bicarbonate, insulin, cortisol, glucagon, urea, creatinine, uric acid, bilirubin and alkaline phosphatase. Unusually hot weather probably contributed to haemoconcentration with a significant (P < 0.001) increase in haematocrit and plasma albumin. A fall in blood glucose, with a rise in FFA and glycerol were consistent with long distance riding and were associated with a reduction in plasma insulin and a rise in cortisol and glucagon. The results suggested that the horses were working aerobically and the small increase in blood lactate was likely to be a result of reduced tissue perfusion. Plasma urea, creatinine and bilirubin increased during the 80 km ride and were still high the next morning. Blood samples were taken from 2 horses that became exhausted and were forced to retire and the results from these animals indicate the slow rate of recovery. It is suggested that haemoconcentration with reduced tissue perfusion might contribute to exhaustion during long distance exercise and that the speed of recovery might be improved by the intravenous administration of balanced electrolyte solutions.

Animals↗
PubMed1978

Biochemical changes in horses during a 50-mile endurance ride.

Blood samples were taken from 15 horses before and after a 50-mile ride to examine the changes occurring in some biochemical constituents. There was a significant (P less than 0.05) decrease in plasma potassium, calcium and magnesium concentrations and a rise in inorganic phosphate but there was no alteration in plasma sodium, chloride or protein levels or change in haematocrit. After the ride there was a highly significant (P less than 0.01) fall in blood glucose corresponding with increased lipolysis and a rise in plasma free fatty acids (P less than 0.001) and glycerol (P less than 0.001). There was a modest increase in blood lactate and a rise in plasma creatine phosphokinase. The results of this preliminary investigation are discussed in relation to the problem of exhaustion in horses during endurance rides.

Animals↗
PubMed1978

Porcine malignant hyperthermia. VI: the effects of bilateral adrenalectomy and pretreatment with bretylium on the halothane-induced response.

The effects of bilateral adrenalectomy, together with the i.v. administration of bretylium tosylate 20 mg kg-1 on halothane-induced malignant hyperthermia (MH), were investigated in six Pietrain pigs. All six animals survived the halothane challenge, and failed to show any signs of increased muscle metabolism. Bilateral adrenalectomy alone prevented halothane-induced MH in three out of four Pietrain pigs, whereas the i.v. administration of bretylium alone protected only one pig out of an additional four animals studied. The results show that complete adrenergic blockade inhibits the susceptibility of Pietrain skeletal muscle to halothane and that the adrenal medulla makes an important contribution to this response.

Adrenalectomy↗
PubMed1978

A technique for measuring hepatic blood flow and oxygen consumption in the anaesthetised pig.

A technique for implanting a catheter in the hepatic vein of anaesthetised pigs is described. Hepatic blood flow (mean 1100 ml/min +/- 180 ml/min SEM) was estimated by the hepatic uptake of indocyanine green and the oxygen consumption by the liver (mean 62 ml/min +/- 3.4 ml/min SEM) was calculated from the difference in oxygen content between arterial and hepatic venous blood.

Anesthesia↗
PubMed1977

Anaesthesia of pigs sensitive to malignant hyperthermia.

During general anaesthesia some pigs develop a hyperthermic response which is often fatal. The syndrome is most common in pigs which are susceptible to stress and have a low proportion of body fat. On the basis of an experimental investigation in Pietrain pigs recommendations are presented for the clinical management and treatment of susceptible animals.

Anesthesia↗
PubMed1977

Porcine malignant hyperthermia. V: Fatal hyperthermia in the Pietrain pig, associated with the infusion of alpha-adrenergic agonists.

The effects of the administration of noradrenaline alone, and noradrenaline with either phentolamine or propranolol, on thermogenesis and substrate mobilization were investigated in six Pietrain (MH-susceptible) and six Large White (unsusceptible) pigs. The infusion of noradrenaline alone produced a significantly increased lipolytic response and a significantly decreased hyperglycaemic response in Pietrain pigs compared with the Large White breed. Although noradrenaline alone produced only a small increase in body temperature in both breeds, the administration of noradrenaline with propranolol in two Pietrain pigs was associated with the development of fatal hyperthermia. In a further experiment, phenylephrine or isoprenaline was infused into six Pietrain pigs. Three pigs, receiving phenylephrine, became hyperthermic and died, whereas isoprenaline had no effect on body temperature. The results demonstrate the importance of alpha-adrenergic stimulation to heat production in MH-susceptible pigs.

Adrenergic alpha-Agonists↗
PubMed1977

Anaesthetic and surgical technique for bilateral adrenalectomy in stress sensitive pigs.

A technique for anaesthesia of Pietrain pigs using thiopentone or ketamine, ventilation with nitrous oxide and oxygen and muscle relaxation with pancuronium, is described. Bilateral adrenalectomy was carried out by a mid line laparotomy and details of the surgical technique are illustrated. Four of the 10 animals died 7--13 hours after surgery with a hyperthermic response.

Adrenalectomy↗
PubMed1976

Porcine malignant hyperthemia IV: Neuromuscular blockade.

The effect of tubocurarine and pancuronium on the initiation or prevention of porcine malignant hyperthermia (MH) was investigated in Pietrain pigs. Tubocurarine 0.6 mg/kg body weight inhibited a suxamethonium-induced response in three pigs, but failed to prevent a fatal halothane-induced response in a further four pigs. Pancuronium 0.2 mg/kg body weight was given to six pigs before a halothane challenge. Three animals developed MH and died; the remainder succembed only after reversal of the neuromuscular blockade. The partial protection afforded by large doses of pancuronium is discussed in relation to the ability of previous muscle activity to influence the sensitivity to halothane.

Animals↗