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Biomedical subjects

G Murphy

Publications and source records attributed to G Murphy.

At least 451 records · Page 25Linked to original sources
PubMed1975

Sutureless epicardial pacemaker lead: a satisfactory preliminary experience.

The first pacemaker systems used the epicardial electrode. The transvenous endocardial electrode rapidly supplanted the epicardial electrode since it could be positioned with less morbidity and mortality and was associated with a lower incidence of wire breakage. The long term complication rate of the transvenous electrode had not been inconsequential. The sutureless epicardial electrode combines the greater reliability of the epicardial lead system with the ease of insertion and low morbidity of the endocardial lead system. We have used this electrode in 33 patients. The electrode was positioned using the subxiphoid approach and local anesthesia in most patients. There have been few complications and none that resulted in long term morbidity. There have been no deaths related either to the operative approach or to the pacing system. There has been no instance of lead failure during the follow-up period.

Aged↗
PubMed1974

Enzyme synthesis in the regulation of hepatic "malic" enzyme activity.

A homogeneous preparation of ;malic' enzyme (EC 1.1.1.40) from livers of thyroxine-treated rats was used to prepare in rabbits an antiserum to the enzyme that reacts monospecifically with the ;malic' enzyme in livers of rats in several physiological states. Changes in enzyme activity resulting from modification of the state of the animal are hence due to an altered amount of enzyme protein. The antiserum has been used to precipitate out ;malic' enzyme from heat-treated supernatant preparations of livers from both adult and neonatal rats, in a number of physiological conditions, that had been injected 30min earlier with l-[4,5-(3)H]leucine. The low incorporations of radioactivity into the immunoprecipitable enzyme have permitted the qualitative conclusion that changed enzyme activity in adult rats arises mainly from alterations in the rate of enzyme synthesis. The marked increase in ;malic' enzyme activity that occurs naturally or as a result of thyroxine treatment of the weanling rat is likewise due to a marked increase in the rate of enzyme synthesis possibly associated with a concurrent diminished rate of enzyme degradation.

Age Factors↗
PubMed1973

Progesterone and the metabolic control of the lactose biosynthetic pathway during lactogenesis in the rat.

1. Lactogenesis was initiated in pregnant rats by ovariectomy, thereby causing progesterone withdrawal, after which the mammary tissue was analysed for contents of enzymes and metabolites concerned with the biosynthesis of lactose. 2. Lactose synthesis increased about 126-fold with little or no accompanying change in the contents of most metabolic intermediates or in the adenine nucleotide energy charge. 3. Comparison of mass-action ratios with equilibrium constants showed that phosphoglucomutase (EC 2.7.5.1), UDP-glucose pyrophosphorylase (EC 2.7.7.9) and UDP-glucose epimerase (EC 5.1.3.2.) catalysed reactions close to equilibrium. Nucleoside diphosphokinase (EC 2.7.4.6.) activity was very high and probably equilibrates the UTP-UDP and ATP-ADP couples. Lactose synthetase and hexokinase (EC 2.7.1.1) appeared to catalyse rate-limiting reactions. 4. Large increases were seen of UDP-glucose pyrophosphorylase (5-fold), lactose synthetase A protein (3.8-fold) and alpha-lactalbumin (28-fold), but not of hexokinase, phosphoglucomutase, UDP-glucose epimerase, nucleoside diphosphokinase or glucose 6-phosphate dehydrogenase (EC 1.1.1.49) activities. 5. It appeared that the increased lactose synthesis was largely accounted for by the increased lactose synthetase A protein activity and alpha-lactalbumin.

Adenine Nucleotides↗