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Biomedical subjects

C Wilkinson

Publications and source records attributed to C Wilkinson.

At least 127 records · Page 7Linked to original sources
PubMed1987

Beta-adrenergic blockade restores glucose's antiketogenic activity after exercise in carbohydrate-depleted athletes.

1. The development of post-exercise ketosis is not abolished by the ingestion of glucose immediately after exercise, despite inducing high insulin/glucagon ratios in the peripheral (and therefore by implication in the portal) blood. 2. To investigate the possibility of autonomic control of the liver influencing its sensitivity to the major counter-regulatory hormones, we administered 50 g glucose, either on its own, or together with 0.5 mg prazosine, 40 mg propranolol, or 15 mg propantheline, to forty-seven 48 h carbohydrate-starved athletes who had just run 25 km. 3. The blood 3-hydroxybutyrate concentration rose from 0.30 +/- 0.05 (mean +/- S.E. of mean) to 0.52 +/- 0.08 mmol/l with exercise, and then to 1.32 +/- 0.40 mmol/l at 6 h after exercise in subjects who had ingested only glucose after exercise. 4. The effects of prazosine and propantheline on the blood ketone body concentration at 2 h after exercise was not statistically significant. Propranolol, on the other hand, significantly lowered the blood 3-hydroxybutyrate concentration (compared with controls) to 0.09 +/- 0.03 mmol/l at 3 h (P less than 0.01), and 0.35 +/- 0.08 mmol/l at 6 h (P less than 0.01) after exercise. 5. The plasma insulin, glucagon, glucose and free fatty acid concentrations were unaffected by propranolol, indicating that the antiketogenesis was the result of a direct effect on ketone body metabolism. 6. Since beta-adrenergic blockade has not previously been shown to have antiketogenic activity, except in somatostatin-induced hyperketonaemia, it is concluded that its effectiveness in post-exercise ketosis can probably be ascribed to a functional hepatic insulin and glucagon deficiency.

3-Hydroxybutyric Acid↗
PubMed1987

Agreement between two measures of alcohol consumption.

Responses on the Quantity-Frequency Questionnaire (QF) were compared with those on the self-report diary. The QF was administered to 778 general practice patients prior to their consultation and the same patients completed the diary at home within 24 hours. The diary overestimated the number of nondrinkers in the population relative to the QF and classified a higher proportion of patients as heavy drinkers. The QF failed to detect 78% of heavy drinkers identified by the diary. Significantly (p less than .001) more alcohol was reported to be consumed overall on the diary (mean, 10.51 drinks/week) than on the QF (mean, 6.87 drinks/week). The relationship between responses on the two measures was nonlinear. At low consumption levels patients indicated drinking twice as much on the diary as on the QF, but the magnitude of the reported consumption difference decreased with increasing consumption levels. The results are discussed in terms of their implications for self-report measures of alcohol consumption.

Adolescent↗
PubMed1986

The locus of inhibition of NADH oxidation by benzothiadiazoles in beef heart submitochondrial particles.

6-Chloro-1,2,3-benzothiadiazole (6-Cl-BTD) is an effective inhibitor of NADH oxidase (site I) but not of succinate oxidase in beef heart submitochondrial particles. For NADH oxidase activity maximal inhibition (80-85%) was achieved at 0.75mM 6-Cl-BTD. A similar level of inhibition was also observed (half maximal inhibitory concentration 0.5mM) towards NADH-duroquinone reductase; NADH-juglone reductase was slightly inhibited (23%) at 0.5mM 6-Cl-BTD while NADH-ferricyanide reductase was unaffected. The data suggest that 6-Cl-BTD interacts with an electron transport site on the oxygen side of NADH dehydrogenase and inhibitory studies with 6-Cl-BTD and rotenone indicate that it might correspond with one of the two sites affected by rotenone. The substituted 1,2,3-benzothiadiazoles (BTDs) are perhaps best known for their activity as inhibitors of cytochrome P-450-mediated mixed-function oxidation (MFO). In vitro, the BTDs are potent inhibitors of MFO activities in microsomes from mammalian liver and insect tissues and they have been demonstrated to inhibit aminopyrine metabolism in perfused rat liver. In vivo, they reportedly prolong hexobarbital sleeping time in mice, inhibit the irreversible binding of labeled trichloro-ethylene to microsomal protein and effectively enhance the toxicity (synergize) of pyrethrin, organophosphorus-containing and carbamate insecticides to insects.

Animals↗
PubMed1983

Effects of myocardial infarction on perioperative cardiac complications.

Of 1104 consecutive noncardiac operations on 981 patients using general anesthesia, 63 were performed on 53 patients who had had a previous myocardial infarction. Patients with a previous infarct were compared to those with no prior infarct to determine the influence of a previous infarct on perioperative cardiac complications. Two of the 53 patients with a previous myocardial infarction (3.8%) had perioperative myocardial infarction, compared to 0.4% (4/928) of patients with no prior history of myocardial infarction (P less than 0.05). Ventricular tachycardia (P less than 0.05) and cardiac death (P less than 0.01) were more frequent in patients with a previous myocardial infarction compared to those with no prior infarct. All patients with a previous myocardial infarction who developed cardiac complications underwent vascular procedures (P less than 0.005) and were over 77 years of age. The two patients who reinfarcted experienced intraoperative hypotension (P less than 0.05). Fourteen of the 53 patients with a history of a myocardial infarction (26.4%) had previous coronary artery bypass surgery; no perioperative cardiac complications occurred in these patients.

Adult↗
PubMed1982

Braxton-Hicks contractions and fetal breathing movements.

Fetal breathing movements were observed for periods of approximately 100 minutes in 10 women at 36-42 weeks' gestation. Simultaneous recordings of uterine activity were made using an external tocograph. Fetal breathing movements were present at the onset of 82 Braxton-Hicks' contractions. There was a significant change in the rate of fetal breathing with a trough before the acme of the contraction, followed by a peak as uterine activity decreased. It is suggested that these changes are related to pressure on the fetus during the contraction and probably are unrelated to changes in fetal oxygenation.

Female↗
PubMed1977

Characteristics of psychiatric residency programs and quality of education.

As part of the fiscal year 1975 NIMH review of all psychiatric education grants, 144 basic residency training programs were thoroughly examined. In order to generate hypotheses about factors related to quality, the authors divided these grants into those given high priority rankings, those ranked in the middle, and those disapproved. Faculty and trainee characteristics, aspects of the service system, and organizational, educational, and evaluation factors were strongly related to quality. In general, good programs had a primary theoretical orientation with a tolerance for diversity, were not administratively responsible for community mental health centers but had strong community service ties, and tended to be in university settings. The authors point out the need to determine psychiatry's role vis-à-vis primary care and to develop a clear understanding of the place psychiatry will have in the health and mental health systems.

Delivery of Health Care↗
PubMed1977

Electrical burns.

Explore the source record for details and available documents.

Burns, Electric↗
PubMedDate not supplied

The hTERTalpha splice variant is a dominant negative inhibitor of telomerase activity.

The telomerase catalytic subunit (hTERT) is an essential component of the holoenzyme complex that adds telomeric repeats to the ends of human chromosomes. Maintenance of telomeres by telomerase or another mechanism is required for cell immortalization, and loss of telomeric DNA has been proposed as a trigger for cellular senescence. Available evidence suggests that regulation of telomerase activity primarily depends on transcriptional control of hTERT. However, several human tissues as well as some normal cell strains have been shown to express low levels of hTERT mRNA even though they lack telomerase activity. We have previously identified six splice variants of hTERT, including a "deletion" variant (hTERTalpha) that is missing conserved residues from the catalytic core of the protein. Several of the deletion variants have been detected in normal and developing human tissues. We now show that hTERTalpha inhibits endogenous telomerase activity, which results in telomere shortening and chromosome end-to-end fusions. Telomerase inhibition induced a senescence-like state in HT1080 cells and apoptosis in a jejunal fibroblast cell line. These results suggest a possible role for hTERT splice variants in the regulation of telomerase activity.

Alternative Splicing↗