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Biomedical subjects

D Lister

Publications and source records attributed to D Lister.

At least 55 records · Page 3Linked to original sources

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↗

Porcine malignant hyperthermia. I: Metabolic and physiological changes.

Porcine malignant hyperthermia was studied in seven Pietrain pigs under standardized experimental conditions. In five animals malignant hyperthermia was triggered with suxamethonium and halothane, but in two pigs suxamethonium alone was used. Characteristic metabolic and physiological changes were found and these are discussed with regard to a possible mechanism to explain the malignant nature of the syndrome.

Animals↗

Porcine malignant hyperthermia. II: Heat production.

The contributions of aerobic and anaerobic muscle metabolism to the heat produced in porcine malignant hyperthermia were studied in seven Pietrain pigs. Oxygen consumption measurements were used to calculate the increase in muscle temperature as a result of aerobic metabolism and this was compared with the observed muscle temperature. The results show that in the initial stage of porcine malignant hyperthermia heat production is largely aerobic in origin. Terminally, aerobic metabolism can account for about half the observed temperature increase.

Animals↗

Malignant hyperthermia in Belgian Landrace pigs rested or exercised before exposure to halothane.

Thirteen of 31 Belgian Landrace pigs developed malignant hyperthermia (MH) after breathing halothane. A short period of exercise 1 h before the administration of the triggering agent increased the incidence of the syndrome to 100% in eight similar pigs. Clinical symptoms were more marked and developed more rapidly in the exercised pigs. All the reacting pigs became typically acidotic, developed rigor and died. Serum Na+, K+, Ca2+, c.p.k., l.d.h. and protein concentrations were increased to a variable extent during the reaction and there was an increase in p.c.v. also. No hyperglycaemia was detected in pigs which were rested before receiving halothane. Four of the eight exercised pigs became markedly hyperglycaemic and plasma noradrenaline increased to higher values. Phosphocreatine and ATP decreased to low values and lactate increased in the muscles of all pigs which reacted. At the time of death, muscle glycogen had decreased significantly in the rested, but not in the exercised, MH pigs.

Animals↗

Porcine malignant hyperthermia. III: Adrenergic blockade.

The effects of the establishment of an adrenergic blockade on suxamethonium-induced porcine malignant hyperthermia (MH) were investigated in Pietrain pigs. Six animals were fed reserpine 10 mg daily for 7 days and then challenged with suxamethonium. Three survived but the remainder developed fatal MH. In a further study of 10 pigs, either phentolamine 40 mug/kg/min or propranolol 50 mug/kg/min were administered for 30 min before suxamethonium stimulation and continued for the duration of the experiment. The five year beta-blocked pigs all became hyperthermic and died whereas the phentolamine-treated group survived. However, both alpha adrenergic blockade and successful reserpinization failed to prevent the abnormal muscle response to the first dose of suxamethonium.

Adrenergic alpha-Antagonists↗

Breed differences in the position of the urethral meatus of gilts.

In a strain of Pietrain the distance between the vulva and the urethral meatus is greater than that of other breeds of pig. This difference is such that it is difficult to catheterise the bladders of Pietrain gilts since the available specula are either too short in length or too wide in diameter.

Animals↗

Treatment of porcine malignant hyperthermia. A review based on experimental studies.

The metabolic and endocrine changes in porcine malignant hyperthermia are described and the importance of the catecholamine response emphasised. The relative effectiveness of several different therapeutic agents in the treatment of this syndrome in the Pietrain pig are described and the importance of a common link with the catecholamine response discussed.

Animals↗

Correction of adverse response to suxamethonium of susceptible pigs.

The adverse response to suxamethonium in susceptible pigs has been shown to be associated with changes in serum free thyroxine index. Pyrexia and acidosis can be controlled by the cautious administration of L-triiodo-thyronine (T-3). Successful correction has been achieved in eight episodes, and in six of these, where it was intended, rapid, uneventful, and complete recovery occurred.

Acidosis↗