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Biomedical subjects

L Kirby

Publications and source records attributed to L Kirby.

36 records · Page 2Linked to original sources
PubMed1991

Regulation of ketone formation and phosphoenolpyruvate carboxykinase activity in the small intestinal mucosa of infant rats.

We studied the effect of different hormones added in vivo or in vitro on ketogenesis and phosphoenolpyruvate carboxykinase (PEPCK) activity in the small intestinal mucosa of suckling rats. Injection of insulin or dexamethasone in vivo or of an antiglucagon antiserum decreased the rate of ketone formation in the mucosa whereas injection of anti-insulin antiserum led to increased mucosal ketogenesis. PEPCK activity in the mucosa was decreased by the antiglucagon serum but was not affected by insulin or anti-insulin serum injections. Both liver and brown fat PEPCK responded as expected with the activity being elevated by anti-insulin serum and depressed by both insulin and antiglucagon serum. In the in vitro experiments, no effect of any of the agents on PEPCK was found. Ketone formation was suppressed in vitro by insulin or dexamethasone addition to the medium.

Animals↗
PubMed1984

Partial deletion of the beta-globin gene: a common beta-thalassaemia allele in Asian Indians.

We have examined 11 families of Asian Indian origin, who are segregating beta-thalassaemia alleles, for coupled restriction enzyme site markers. A beta-thalassaemia deletion allele, which removes over 600 base pairs, is a common cause of thalassaemia in this population. This deletion can be conveniently detected in AvaII restriction enzyme digests. Consequently AvaII digests are particularly informative in this population because both the deletion and a coupled restriction site polymorphism may be simultaneously observed.

Alleles↗
PubMed1978

Control of phosphoenolpyruvate carboxykinase in brown adipose tissue of infant rats.

Activity of phosphoenolpyruvate carboxykinase (PEPK) in brown adipose tissue (BAT) of infant rats is high and is depressed by a single injection of corti-costeroid or insulin. Both hormones inhibit synthesis of the enzyme in BAT and increase it in liver. Fatty acid synthetase activity is enhanced by these hormones, but only in BAT. It is suggested that corticosteroids may act via insulin release, since both blood glucose and blood insulin levels rise after steroid injection. The difference in response between BAT and liver is ascribed to the difference in adenyl cyclase response in the two tissues.

Adipose Tissue, Brown↗
PubMed1978

Regulation of phosphoenolpyruvate carboxykinase and fatty acid synthetase in brown fat of suckling rats.

Infant rats were injected with prednisolone (0.5-5 mg/100 g wt). This caused phosphoenolpyruvate carboxykinase (PEPCK) activity to rise in liver and to decrease in brown fat. Fatty acid synthetase (FAS) activity remained unchanged in liver but increased in brown fat. A single injection of prednisolone caused hepatic PEPCK activity to remain elevated for at least 7 days. Brown fat FAS also remained high for that period. However, brown fat PEPK activity returned to normal on the third day after the injection. A single injection of prednisolone or cortisone to 5-day-old rats caused a transient elevation of the blood level of insulin and a prolonged decrease in that of growth hormone. No effect on the level of glucagon was noted. Injections of insulin had effects similar to those of prednisolone, i.e. a rise in hepatic and a fall in brown fat PEPCK. Using antibodies prepared to hepatic PEPCK it was shown that the observed changes were due to changes in the rate of synthesis of the enzyme. Using actinomycin D indirect evidence was obtained that changes in FAS activity of brown fat were also due to changes in the synthetic rate.

Adipose Tissue, Brown↗
PubMed1976

Changes in tyrosine transaminase and phosphoenolpyruvate kinase activities during short term incubation of fetal liver.

Incubation of fetal rat liver homogenates at 37 degrees for 2-3 hr increased PEPK activity in the 100,000 X g supernatant 5-fold and TTA activity 10-fold. At the same time, activity in the 100,000 X g pellet decreaed and no change was observed in the whole homogenate. It is concluded that during incubation of fetal liver pieces or homogenates in vitro, a redistribution of enzymes occurs between cell particles and cell sap. It is suggested that release of enzyme into the cell sap may be the first stimulus for subsequent enzyme synthesis which occurs after birth.

Animals↗
PubMed1975

High glucose concentration and phosphoenolpyruvate carboxykinase activity in human and rat fetal liver cultures.

In cultures of human and rat fetal liver, phosphoenolpyruvate carboxykinase activity increases during the first 24 hr of culturing. This increase can be suppressed by adding cycloheximide to the culture medium or by adding a high glucose concentration. This, however, applies only to human fetal liver and to fetal liver from rats obtained just before term. In younger rat fetal liver, glucose, on the contrary, increases the activity of phosphoenolpyruvate carboxykinase. A high glucose concentration in the medium also leads to higher citrate cleavage enzyme activity and to lower alpha-glycerolphosphate dehydrogenase (cytoplasmic) activity in rat fetal liver cultures.

Animals↗
PubMedDate not supplied

A glider swing intervention for people with dementia.

The soothing, repetitive movement of rocking and swinging is well known to anyone who has enjoyed a porch swing or rocking chair. Positive effects of rocking have been reported. However, investigations on its effect in people with dementia are limited. The purposes of this quasi-experimental, repeated-measures design study were to measure the effects of a glider swing on emotions, relaxation, and aggressive behaviors in a group of nursing home residents with dementia (n = 30). Data were obtained during a 5-day baseline phase, a 10-day intervention phase, and a 5-day posttreatment phase. Subjects were placed on the glider for 20 minutes each day during the intervention phase. The results of the study indicate that the glider intervention significantly improved emotions and relaxation. The most noted changes were found after 10 minutes of swinging. However, no differences were found in aggressive behaviors.

Adult↗
PubMedDate not supplied

Challenges of implementing intervention research in persons with dementia: example of a glider swing intervention.

Intervention studies for persons with dementia present many challenges. This article describes challenges encountered in conducting a glider swing intervention study for persons with dementia and the strategies used to manage the problems encountered. The overall purpose of a quasi-experimental study was to explore the effects of a glider swing intervention on emotions, relaxation, and aggressive behaviors in nursing home residents with dementia. Suggestions for investigators conducting intervention studies for persons with dementia are provided.

Adult↗
PubMedDate not supplied

Reversible ischemia determined by xenon-enhanced CT after 90 minutes of complete basilar artery occlusion.

Intraarterial thrombolytic therapy decreases mortality in the treatment of acute basilar artery occlusion. An acute decrease in cerebral blood flow (CBF) (<12 mL/100 g per minute) has been reported to invariably result in infarction. We report a case of acute basilar artery occlusion, recanalized within 90 minutes, with reversal of CBF of less than 6 mL/100 g per minute. After reperfusion, areas with persistent CBF of 6 mL/100 g per minute resulted in infarctions on subsequent CT studies. Parenchymal viability is possible after 90 minutes of posterior CBF of 6 mL/100 g per minute.

Acute Disease↗