Carbohydrate and lipid metabolism in open-heart surgery

Carbohydrate and lipid metabolism was studied in 8 patients who underwent open-heart surgery with the aid of extracorporeal circulation. Hyperglycemia was observed during perfusion. Despite the high glucose levels during perfusion, insulin responses were depressed. A rise of insulin levels was observed one hour after perfusion, and at the same time the glucose levels dropped. Suppression of insulin secretion during perfusion may be the result of increased catecholamine secretion, induced hypothermia, or heparin administration. High levels of non-esterified fatty acids (NEFA) and low levels of triglycerides were observed immediately before, during, and after perfusion while heparin was being utilized. This phenomenon was considered to be strongly affected by the use of heparin. The levels of growth hormone were depressed during perfusion but significantly elevated one hour after the end of perfusion. These phenomena may be caused by the fluctuations in glucose and NEFA levels.

Effect of serum on the growth of Balb oT3 A31 mouse fibroblasts and an SV40-transformed derivative

The effect of serum on the growth properties of non-transformed Balb 3T3 A31 and SV40-transformed Balb 3T3 A31 was studied. The concentration of serum in the growth medium of non-transformed cells had little effect on the initial population doubling time, but did regulate the cell density at which the population became quiescent in G1. The doubling time of transformed cells, however, was increased significantly as the concentration of serum was decreased below 4%. This effect on the growth of transformed cells was seen at serum concentrations so low that non-transformed cells did not complete one population doubling. Flow microfluorometric analysis of these populations indicated that the primary effect of different serum concentrations on the non-transformed cells was to modulate the average residence time in G1, whereas, all the cell cycle phases of the transformed cells were affected by serum. At saturation densities, the non-transformed cells became quiescent in G1, but the transformed cells still traversed the cell cycle and their saturation density appeared to be a balance between cell production and cell death occurring primarily in the G1 phase of the cell cycle.

Myocardial metabolism during prolonged selectived hypothermic coronary perfusion

In the study discussed below, we assessed the myocardial protection provided by our method of selective hypothermic coronary perfusion. Using arterial and coronary venous blood samples, the following biochemical aspects of myocardial metabolism were calculated: 1) coronary arteriovenous (A-V) pH difference, 2) O2 difference, 3) CO2 difference, 4) respiratory quotient, 5) coronary A-V pyruvate difference, 6) lactate difference, 7) cardiac excess lactate, and 8) redox potential difference. Results indicate that, during coronary perfusion performed according to out method, metabolic changes are minimal and easily reversible shortly after coronary perfusion is terminated.