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Biomedical subjects

K Lee

Publications and source records attributed to K Lee.

At least 901 records · Page 50Linked to original sources

Macrophage factor that induces neutral protease secretion by normal rabbit chondrocytes. Studies of some properties and effects on metabolism of chondrocytes.

Normal rabbit-articular chondrocytes secrete very small amounts of degradative enzymes in culture. Rabbit peritoneal macrophages, when activated with lipopolysaccharides, release a factor in the medium which stimulates the chondrocytes to produce significantly high levels of collagenase and other neutral protease for 2-3 days. The soluble mediator from macrophages appears to be a polypeptide with a molecular weight of 13000-15000 and can be inactivated by short-term treatment with trypsin or pronase. The enzyme-synthesis by chondrocytes can be stimulated to the same extent by repeated addition of the macrophage-medium. The metabolism of chondrocytes is altered due to the presence of this mediator. The cellular proliferation is diminished, while the rates of degradation as well as biosynthesis of the matrix are increased. These studies suggest the possibility that in the conditions such as osteoarthritis, where the synovial cells may not play an active role in cartilage degradation, the proteases can be produced by the cartilage cells themselves after the stimulation by macrophage-derived mediators. These intrinsic enzymes may be responsible for the slow, but progressive degeneration of cartilage tissue.

Animals↗

Platelet aggregation and fibrinolytic activity in young alcoholics.

Alcoholism has been shown to predispose to cerebrovascular thrombosis in normotensive males under the age of 50. To elucidate this phenomenon platelet aggregation and fibrinolytic activity were studied in 29 alcoholic males under 50 years of age who showed no evidence of acute cerebrovascular disease. Age matched healthy nonalcoholic volunteers made up the control population. Platelet aggregation did not differ significantly (P greater than 0.05) in the two groups. Fibrinolytic activity was significantly reduced in the alcoholics as compared to the controls (P = 0.005). The data suggest that the alcoholics have an increased thrombotic tendency. This may cause alcoholics to be at a greater risk of suffering stroke at an early age.

Adult↗

Phosphorylating-dephosphorylating enzymes of avian oviductal secretions.

Avian oviductal fluids contain phosphorylating-dephosphorylating enzymes that might function in sperm-oocyte interactions. Phosphorprotein phosphatase and protein kinase have been purified 20-fold and 40-fold, respectively. The latter easily aggregates and is highly labile. Other properties are comparable to those of holoenzymes.

Animals↗

Long term effects of Marek's disease vaccination with cell-free herpesvirus of turkey and age at debeaking on performance and mortality of white leghorns.

Three-hundred-sixty, day-old Single Comb White Leghorn chicks were randomly placed in 8 treatment combinations. The combinations consisted of vaccinated or nonvaccinated chicks that were either not debeaked, or debeaked at day-old, 4 weeks old, or 8 weeks old. Vaccinated birds received 6,000 plaque forming units of cell-free herpesvirus of turkey vaccine per chick at day-old. Debeaking was performed by removing approximately two-thirds of the upper beak. Data were analyzed at the 5% level of probability. During the growing period (8 to 20 weeks of age), averag daily feed consumption per bird and feed efficiency for the vaccinated birds were not significantly different from those for the nonvaccinated. Regardless of the age at which debeaking was performed, the debeaked birds consumed significantly less feed and had superior feed efficiency than the nondebeaked birds. These traits were not significantly different among the various debeaked groups. Vaccination, or debeaking, or age at debeaking did not significantly influence mortality during the growing period. During the laying period (20 to 84 weeks), a significantly higher percentage of extra large eggs and a significantly lower percentage of medium eggs were collected from the vaccinated birds in comparison to those collected from the nonvaccinated. Also, average egg weight for the vaccinated birds was significantly heavier than that for the nonvaccinated. Debeaking at either 4 weeks or at 9 weeks of age caused a significant reduction in egg weight. Vaccination, or debeaking, or age at debeaking did not significantly influence hen-day egg production. Feed efficiency between the vaccinated and the nonvaccinated birds was not significantly different. Debeaking tended to improve feed efficiency. Vaccination as well as day-old debeaking significantly reduced laying house mortality. Debeaking the birds either at 4 weeks or at 8 weeks of age reduced laying house mortality numerically.

Animals↗

The association of kernicterus with bacterial infection in the newborn.

A total population of 29,395 neonates cared for in the six-year period from 1971 to 1976 was reviewed for evidence of autopsy-proven kernicterus. A total of 327 neonates died and 232 were autopsied. The only cases of kernicterus occurred in four near-term infants with antemortem proven sepsis. All four of these infants weighed more than 2,200 gm and were delivered after gestations of either 36 or 37 weeks. These cases of kernicterus occurred during a period when more aggressive management of hyperbilirubinemia in low-birth-weight infants had apparently eliminated immaturity as a predisposing factor in the development of kernicterus, uncovering bacterial infection as the major remaining etiologic co-factor.

Bacterial Infections↗

Alcohol-induced brain damage and liver damage in young males.

37 alcoholic males under the age of 35 were examined clinically, by psychometric tests, by computerised tomography (CT scans), and by liver biopsy. Factors other than alcoholism that might have caused brain damage were excluded. The prevalence of brain damage in this group was far greater than that of severe liver damage: 59% were intellectually impaired and 49% had cerebral atrophy on CT scan, whereas only 19% had cirrhosis. There was no significant correlations between the degree of liver damage and the degree of intellectual impairment (p greater than 0-05), nor between the degree of intellectual impairment and the presence of cerebral atrophy. The CT scan is an inadequate measure of functional brain damage, psychometric testing is preferable. Other neurological complications of alcoholism were not impressive. Disabling intellectual impairment may be the earliest complication of chronic alcoholism and may arise early in the alcoholic career.

Adult↗

Computed tomography in alcoholic cerebellar atrophy.

This is a controlled CT evaluation of the infratentorial region in 41 male alcoholics under age 35. Criteria for the presence of atrophy are outlined. Twelve patients had cerebellar atrophy. Vermian atrophy was present in all. Atrophy of the cerebellar hemispheres was demonstrated in eight patients as well. The results are statistically significant when compared to an age-matched group of 40 non-alcoholic males among whom two cases of vermian atrophy were found. There were clinical signs of alcoholic cerebellar atrophy in one patient only. The disparity between the clinical and the radiological data are discussed with reference to previous pneumoencephalographic findings.

Adult↗

The contribution of economics to health service planning.

The increased emphasis on the need consciously to plan the future development of the NHS has, in recent years, focused attention on the availability of skills and techniques which might help planners in their attempts to elucidate objectives and the best way of achieving them. This paper sets out the contribution economics can make to health service planning and reviews some of the recent developments in this field.

Cost-Benefit Analysis↗