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Biomedical subjects

D Knight

Publications and source records attributed to D Knight.

86 records · Page 5Linked to original sources
PubMed1980

Red cell cholesterol enrichment and spur cell anemia in dogs fed a cholesterol-enriched atherogenic diet.

A diet supplemented with cholesterol and coconut oil is atherogenic in dogs. The purpose of the present study was to examine the effects of this diet on red cells in pure-bred beagles and greyhounds. Within 3 days after the initiation of this diet red cell cholesterol/phospholipid increased and membrane fluidity decreased, with maximum changes attained by 12 weeks. Serum lipoprotein cholesterol/phospholipid also increased, and serum from cholesterol-fed dogs transferred cholesterol to normal red cells. Significant abnormalities of liver function developed in all cholesterol-fed dogs. Hematocrit declined beginning at 6 weeks, with a parallel increase in osmotic fragility. Reticulocytes were elevated in beagles but normal in greyhounds. Red cell morphology resembled acanthocytes or spur cells. All red cell parameters returned to normal within 4 weeks after stopping the diet. These studies demonstrate that a cholestrol-enriched, atherogenic diet causes profound and reversible changes in the lipid composition, membrane fluidity, and morphology of red cells in dogs.

Anemia, Hemolytic↗
PubMed1979

A pilot study on left ventricular dimensions and wall stress before and after submaximal exercise.

Left ventricle dimensions and wall stress were measured echocardiographically before and immediately after exercise in 14 athletes and 7 control subjects. Our findings suggest that afterload is an important determinant of cardiac performance and wall hypertrophy in athletes. In spite of major changes in heart rate and blood pressure, left ventricular wall stress remains unchanged following submaximal exercise, in trained and untrained hearts. It would appear that the changes in heart size during exercise are to a large extent limited in untrained ventricles, as smaller left ventricular dimensions are required, to "normalise" wall stress. This results in a lower stroke volume for a given stroke dimensional change. Consequently cardiac output is a function of heart rate rather than stroke volume in untrained subjects. The effect of increased muscle mass in athletes, is to permit larger left ventricular dimensions for a given afterload, thus stroke volume can be augmented. The increase h/R ratio suggests that afterload is more important than preload in the development of left ventricular hypertrophy in rowers and swimmers.

Adolescent↗
PubMed1978

Lung water changes after thermal burns. An observational study.

Pulmonary extravascular water has been measured as lung thermal volume (LTV) in a group of nine burned patients. Transducer-detectable indicators were used to permit frequent repetition and quick results. Concurrent recordings were made of cardiac output, pulmonary capillary wedge pressure and the usual hemodynamic variables. Moderate elevation of LTV was seen in all, reaching a maximum value before peripheral edema formation was complete. Left heart filling pressures were low as plasma albumin concentration. Clinical pulmonary edema occurred in one patient treated mostly with crystalloid solution. In several, a secondary peak coincided with edema mobilization.

Adult↗
PubMed1977

[Not Available].

Explore the source record for details and available documents.

History, Ancient↗
PubMed1975

Significane of intravascular coagulation in canine endotoxin shock.

The contribution of disseminated fibrin clot formation to the pathogenesis of canine endotoxin shock was explored in control dogs and in those defibrinated with a purified fraction of Malayan pit viper venom. The hemodynamic and humoral responses after the administration of an intravenous challenge dose of Escherichia coli endotoxin were comparable as was mortality. It is concluded that, although the role of the coagulation sequence in canine endotoxin shock is unclear, it does not appear to be determinative.

Animals↗
PubMedDate not supplied

Development of biodegradable injectable thermoplastic oligomers.

Injectable thermoplastic oligomers represent a promising biomaterial for drug delivery provided they possess a melting point at or very near physiologic temperature, as well as a low melt viscosity. One approach would be to prepare an oligolactone. In this paper, we examine the role of different alcohol initiators used in the ring-opening polymerization of epsilon-caprolactone oligomers on the melting point and melt viscosity of the resultant thermoplastics. We found that the initiator used plays a significant role in the final properties of the final oligomer. For primary alcohols, the longer the chain length of the oligomer the lower its melt viscosity, until a chain length of 8 carbons, after which there was no noticeable effect. There was no significant effect observed of primary initiators on the melting point. The use of secondary alcohols produced oligomers with higher viscosities but with reduced overall crystallinity. The use of an unsaturated alcohol, oleyl alcohol, not only reduced the melting point and overall crystallinity but also reduced the melt viscosity of the oligomer. The oleyl alcohol initiated oligomer appears to be a promising vehicle for localized, sustained drug delivery applications.

Biocompatible Materials↗
PubMedDate not supplied

Slipped upper femoral epiphysis--a review of 12 years of experience in Glasgow (1972-1983).

We conducted a retrospective study of 97 cases of slipped capital femoral epiphysis occurring in 77 children. Gradual epiphyseal slip frequently occurred, and complications were more frequent with greater degrees of slips. Diagnostic delay should, therefore, be avoided, and a high index of suspicion is necessary when adolescents with leg pain or limp are examined. Minor epiphyseal slip should be carefully fixed in situ, and we suggest that the remainder undergo a gentle manipulation. Only those hips with a persisting deformity need undergo femoral osteotomy.

Adolescent↗