Old carbon reservoirs were not important in the deglacial methane budget

Permafrost and methane hydrates are large, climate-sensitive old carbon reservoirs that have the potential to emit large quantities of methane, a potent greenhouse gas, as the Earth continues to warm. We present ice core isotopic measurements of methane (Δ¹⁴C, δ¹³C, and δD) from the last deglaciation, which is a partial analog for modern warming. Our results show that methane emissions from old carbon reservoirs in response to deglacial warming were small (<19 teragrams of methane per year, 95% confidence interval) and argue against similar methane emissions in response to future warming. Our results also indicate that methane emissions from biomass burning in the pre-Industrial Holocene were 22 to 56 teragrams of methane per year (95% confidence interval), which is comparable to today.

[Activity of cytoplasmic NADP-dependent dehydrogenase in rat liver during induction of cytochrome P-450 by phenobarbital]

Activity of oxidation enzymes of the pentosephosphate way (glucose-6-phosphate dehydrogenase (EC 1.1.1.49) and 6-phosphogluconate dehydrogenase (EC 1.1.1.44), cytoplasmic malate dehydrogenase (decarboxylating oxaloacetate) (NADP+) (EC 1.1.1.40) and isocitrate dehydrogenase (NADP+) (EC 1.1.1.42) as well as the content of microsomal cytochromes b5 and P-450 in the rat liver have been studied 24 hours after 1, 2, 3, 4 and 5 intraperitoneal administrations of phenobarbital (4 mg per 100 g of the body weight). It is shown that the cytochrome P-450 content increases after a single administration of phenobarbital and then it gradually grows reaching its maximum after 4 administrations and falls after 5 administrations (though it remains high as compared to the control animals). The content of cytochrome b5 increases only after 4 administrations of phenobarbital and after 5th one it returns to the initial level. The content of microsomal gangliosides calculated per 1 mg of microsomal protein decreases after a single administration of phenobarbital and 5 days later it returns to the initial level. Activity of glucose-6-phosphate dehydrogenase increases after a single administration of phenobarbital, that of malate dehydrogenase--after 3 administrations, 6--phosphogluconate-dehydrogenase--after 4 administrations of the preparation. The 5 administrations of phenobarbital makes activity of all the mentioned dehydrogenases return to the initial level. Activity of isocitrate dehydrogenase under given conditions of the experiment does not change.

[Pulmonary microcirculation after distant gamma-therapy of breast and thyroid cancer (perfusion pulmoscintigraphy data)]

A study was made of an effect of irradiation on pulmonary microcirculation using perfusion pulmoscintigraphy indicators. Altogether 13 breast cancer patients (9 with left-side and 4 with right-side involvement) and 9 thyroid cancer patients were examined before and after radiation therapy. Absorbed doses in breast cancer were determined by phantom measurements, for thyroid cancer by calculation. Perfusion pulmoscintigraphy with labeled albumin macroaggregate preceded and followed radiotherapy. Accumulation of the radioactivity of the drug in different pulmonary zones was taken into account. Slight changes of the microcirculation index found after irradiation, lead to a conclusion that in radiation therapy of breast cancer one can observe improvement of the blood flow in the pulmonary arterial system whereas in thyroid cancer a similar effect in the irradiated upper pulmonary zone was not marked. Irradiation of the root of the lung produces a more powerful effect on the pulmonary blood flow. Taking into account a sharp suppression of the arterial blood flow in some lung cancer patients (decreasing chemotherapy efficacy) it is suggested that change of the blood content developing after irradiation be used in the planning of combined therapy of lung cancer.

[Role of the glycerophosphate shunt in regulating oxidation of cytoplasmic NADH and ATP synthesis by liver mitochondria during rat ontogeny]

The activity of alpha-glycerophosphate dehydrogenase rate of alpha-glycerophosphate oxidation and ATP synthesis were determined in the liver mitochondria of 1, 3, 12 and 24-month old rats in norm and two days after thyroxin daily administration in a dose of 0.25 mg per 100 g of body mass. The value of the studied parameters decreases with the age, most considerably--from one to three months and then--from 3 to 24-month age. This evidence for the fact that the role of glycerophosphate shuttle in the energy supply of cells falls with ageing; thyroxin administration evoked almost a two-fold increase of the mentioned parameters in one-month rats and more than three-fold in 12 and 24-month animals. A decrease in the alpha-glycerophosphate dehydrogenase activity with ageing is supposed to be connected with the thyroid gland function.