The importance of adrenal glands in the improved adaptation of trained animals to physical exertion.

The importance of adrenal glands in the adaptation of rats to physical exertion was studied. Exercise training, significantly increased the working ability and prevented the water accumulation in myocardial cells during acute exertion. The latter shift was characteristic of untrained animals. However, adrenalectomy abolished the benefical effect of training on working ability and myocardial adaptation to exertion. The results obtained supported the view that the effect of training is partly mediated through the improved adrenocortical function while adrenal hormones, by regulating the heart metabolism and function, significantly influenced the adaptation of rats to physical exertion.     

The metabolism of skin grafts stored with excess carbon dioxide.

In Japan, the long-term storage of cereals and foods in the presence of excess carbon dioxide is already a practical reality. The present study was conducted to assess the metabolic changes in skin grafts during storage in the presence and absence of excess carbon dioxide, with the aim of seeking a simple and effective method to prolong skin-graft viability during storage. In experiment 1, 120 male Wistar rats weighing 250 to 300 gm were used. A split-thickness skin graft 450 microns in thickness was harvested from the back of each rat with a dermatome and was divided into two pieces for separate storage. One piece was stored in normal air at 4 degrees C (control grafts), and the other was stored in a gas mixture composed of 20% O2, 20% CO2, and 60% N2 at 4 degrees C (CO2 grafts). Metabolic changes in the skin grafts during storage were investigated by ATP and glucose assays. In experiment 2, 60 male Wistar rats were used. Collection and storage of the split-thickness skin grafts were performed as in experiment 1. In both groups, skin grafts were stored for 1, 2, or 3 weeks, and the oxygen consumption rate of each graft was determined. Experiment 3 used 80 male Wistar rats and the same procedure as in experiment 1; split-thickness skin grafts were harvested, divided into two pieces, and stored for 1, 2, or 3 weeks. In both groups, the stored skin grafts were regrafted onto the backs of the same donor rats.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of carbon dioxide inhalation prior to maximal exercise on blood lactate and physical performance

In order to examine the effect of acute respiratory acidosis induced by CO2 inhalation prior to maximal exercise on blood lactate and physical performance, double determinations were carried out for each subject on separate days; one day, after CO2 inhalation and other day, after inhalation of room air. It was observed that in the untrained subjects the CO2 inhalation prior to maximal treadmill exercise does not affect endurance time and maximum aerobic power, whereas blood lactate during recovery was lower in CO2 breathing than that in room air. In addition, no significant difference of 200m sprint time in the athletes was noticed between CO2 and room air while blood lactate after 200m sprint running was significantly lower in the CO2 than that in room air. From these results, it was suggested that the effect of CO2 inhalation prior to maximal exercise as applied here appeared to be mediate through metabolic rather than oxygen transport mechanism, but not related to physical performance.     

Mechanisms of human adaptation to hypoxia

The effects of adaptation to cold-and-hypoxic exposure on the cardiovascular system, lipid peroxidation and concentrations of adaptogenesis involved hormones were studied in male students. The two weeks cold- and hypoxic training was shown to be accompanied by a significant increase of apnea duration, reduced velocity of bradycardia development and a more rapid ECG post-cold and- hypoxic exposure normalization, as well as by inhibition of activation of adrenal cortex and thyroid gland after stress of different nature. The changes of the character of influences between the indices under study, were demonstrated. The correlation analysis showed an increase of the human's adaptive potential and a decrease of its dependence on the adrenal cortex hormones.     

Coenzyme M derivatives and their effects on methane formation from carbon dioxide and methanol by cell extracts of Methanosarcina barkeri.

Extracts of Methanosarcina barkeri reduced methanol and CO2 to CH4 in the presence of H2 and converted methanol stoichiometrically into CH4 and CO2 in the absence of H2. In dialyzed cell-free extracts these reactions were stimulated by 2-mercaptoethanesulfonic acid (coenzyme M) and some derivatives (acetyl and formylcoenzyme M and the oxidized form of coenzyme M), which could be converted to coenzyme M by enzyme systems present in the extracts. Methylcoenzyme M could not be used in these systems.     

The effect of restriction of physical activity on adaptation to prolonged exercise in dogs.

Eight-week restriction of physical activity markedly reduced the capacity for prolonged running. The rate of exercise-induced Tre increases was also significantly higher in comparison with control experiments. At the point of exhaustion blood glucose concentration and muscle glycogen content were similar in the control and cage-confined animals, however the rate of decrease in blood glucose level and muscle glycogen depletion during exercise were higher in the cage-confined dogs than in the controls.     

The effect of carbon dioxide laser surgery on the recurrence of keloids

The efficacy of carbon dioxide laser excision as a primary modality for the treatment of keloids was evaluated. This retrospective study focuses on 31 patients with one or more keloids, 23 of whom were available for follow-up after carbon dioxide laser excision. The patients' ages ranged from 5 to 72 years. There were 16 females and 7 males. One patient was Caucasian, 22 patients were non-Caucasian, and there were no Asians. The keloids that were excised ranged in size from 1 to 30 cm in greatest diameter. One patient had no recurrence of her keloid after carbon dioxide laser excision, 9 patients required steroids to suppress recurrences, and 13 patients were considered failures. Reasons for the failure of this modality, as well as speculation regarding the future of this procedure, are discussed.