Search PubMed⌕ Search

Biomedical subjects

M Kim

Publications and source records attributed to M Kim.

At least 451 records · Page 25Linked to original sources
PubMed1978

Quantitative description of cell cycle kinetics under chemotherapy utilizing flow cytometry.

A discrete time cell cycle kinetics model is developed to account for the effects of cytotoxic chemotherapy, particularly including the existence of cells destined to die. A model structure is determined from related experiments, leaving key parameter values undetermined. These values are found by determining the best least squares fit of the predicted to the observed DNA distribution data at a series of time intervals. The numerical methods include separable least squares, linear inequality constrained least squares and the Gauss--Newton method. This approach is applied to an experiment in which the Ehrlich ascites tumour was given a single dose of bleomycin. The results include several different parameters, including the age response function and a time series of cell age and DNA distributions, which can be used as a basis for further treatment.

Animals↗
PubMed1977

Effect of influenza viral infection on the ingestion and killing of bacteria by alveolar macrophages.

In experimental animals, influenza prediposes the lung to superinfection by reducing the antibacterial efficiency of the alveolar macrophage system. Because such defects may represent abnormalities in ingestion or inactivation of inhaled bacteria, these subcomponents of phagocytosis were tested in mice infected 5 days previously with influenza A virus (NWS or WSN). The mice were exposed to aerosols of Staphylococcus epidermidis and then the rates of bacterial inactivation and percentages of intracellularly located staphylococci were measured. Rates of bacterial inactivation were determined for the left lung by pour-plate enumeration methods. The percentage of ingested bacteria was determined in the in situ perfused right lung by histologically determining the intra- or extracellular location of 100 or more staphylococci. Rates of inactivation of S. epidermidis at 4 hours after bacterial challenge were: control, 90.1 per cent; WSN, 73.0 per cent; NWS, 68.6 per cent, P less than 0.01. The percentage of intracellular staphylococci at 4 hours were: control, 90.9 per cent; WSN, 69.9 per cent; and NWS, 73.8 per cent, P less than 0.01. Microcolonies of proliferating staphylococci were also observed within macrophages of mice infected with each strain of influenza. These experiments demonstrated that in this experimental model, influenzal infection impairs the inactivation of inhaled bacteria by retarding the ingestion of bacteria and by allowing bacteria to proliferate within macrophages.

Animals↗
PubMed1977

[A year's practice of surgery for arteritis after the age of 70 years (author's transl)].

Surgery of the elderly arteritic raises the problem of operative risk due to pre-existing defects at an advanced stage of the arterial disease and the danger of tiring investigations, anesthetics and repeated operations. Out of 271 arteritics operated on during 1975, half (135) were aged over 70 years. 92, i.e. two thirds were operated on at the terminal stage of their arteritis. The operative indications depended on the clinical, arteriographic, psychological and sociological data. The past history in many cases of heart attacks and cerebro-vascular accidents made the utility and necessity of the operation debatable. The technical choice, sympathectomy or plastic operation, depended on which presented the less risk. Although amputation is still necessary for massive gangrene (50 p. cent survival) one should always attempt to save the leg. Lumbar sympathectomy seems less aggressive; reconstructive surgery is, with greater risk, more effective at stage IV. The final result of the year showed 72.6 p. cent survivors including 56.3 p. cent successes and 16.3 p. cent amputations and a mortality of 27.4 p. cent. But all the failures were situated at stage IV of the arteritis, and the disturbances are increased by the patients' age. We can thus say that it is possible to render survival comfortable for three quarters of our operated patients.

Age Factors↗
PubMed1976

Mathematical description of a bursting pacemaker neuron by a modification of the Hodgkin-Huxley equations.

Modifications based on experimental results reported in the literature are made to the Hodgkin-Huxley equations to describe the electrophysiological behavior of the Aplysia abdominal ganglion R15 cell. The system is then further modified to describe the effects with the application of the drug tetrodotoxin (TTX) to the cells' bathing medium. Methods of the qualitative theory of differential equations are used to determine the conditions necessary for such a system of equations to have an oscillatory solution. A model satisfying these conditions is shown to preduct many experimental observations of R15 cell behavior. Numerical solutions are obtained for differential equations satisfying the conditions of the model. These solutions are shown to have a form similar to that of the bursting which is characteristic of this cell, and to preduct many results of experiments conducted on this cell. The physiological implications of the model are discussed.

Animals↗
PubMed1976

Murine pulmonary alveolar macrophages: rates of bacterial ingestion, inactivation, and destruction.

The component processes of phagocytosis (ingestion, inactivation, and destruction of bacteria) were studied in mice by histological and microbiological techniques after aerosol infection with Staphylococcus aureus. Rates of bacterial ingestion and inactivation were (respectively): 0 hr, 37.7% and 0; 1 hr, 64.5% and 45.8%; 2 hr, 75.9% and 67.9%; 4 hr, 82.4% and 84.1%; and 8 hr, 90.7% and 94.8%. Bacterial destruction began 2-4 hr after aerosol infection and affected 80% of the bacteria by 8 hr. Comparison of these processes indicated that bacterial ingestion occurred before inactivation and was 76% complete at 2 hr. Inactivation resulted in death of 84% of the bacteria at 4 hr, and 80% of the bacteria were at least partially destroyed by 8 hr. The mechanism of X-irradiation-induced depression of pulmonary bacterial inactivation was studied in syngeneic mice protected from lethal effects of X-irradiation by chest and pelvic shields or by transplantation of 2 times 10(6) bone marrow cells. Impairments in bacterial inactivation resulted from diminished ingestion of bacteria by macrophages.

Aerosols↗