Preindustrial 14CH4 indicates greater anthropogenic fossil CH4 emissions.

Atmospheric methane (CH4) is a potent greenhouse gas, and its mole fraction has more than doubled since the preindustrial era1. Fossil fuel extraction and use are among the largest anthropogenic sources of CH4 emissions, but the precise magnitude of these contributions is a subject of debate2,3. Carbon-14 in CH4 (14CH4) can be used to distinguish between fossil (14C-free) CH4 emissions and contemporaneous biogenic sources; however, poorly constrained direct 14CH4 emissions from nuclear reactors have complicated this approach since the middle of the 20th century4,5. Moreover, the partitioning of total fossil CH4 emissions (presently 172 to 195 teragrams CH4 per year)2,3 between anthropogenic and natural geological sources (such as seeps and mud volcanoes) is under debate; emission inventories suggest that the latter account for about 40 to 60 teragrams CH4 per year6,7. Geological emissions were less than 15.4 teragrams CH4 per year at the end of the Pleistocene, about 11,600 years ago8, but that period is an imperfect analogue for present-day emissions owing to the large terrestrial ice sheet cover, lower sea level and extensive permafrost. Here we use preindustrial-era ice core 14CH4 measurements to show that natural geological CH4 emissions to the atmosphere were about 1.6 teragrams CH4 per year, with a maximum of 5.4 teragrams CH4 per year (95 per cent confidence limit)-an order of magnitude lower than the currently used estimates. This result indicates that anthropogenic fossil CH4 emissions are underestimated by about 38 to 58 teragrams CH4 per year, or about 25 to 40 per cent of recent estimates. Our record highlights the human impact on the atmosphere and climate, provides a firm target for inventories of the global CH4 budget, and will help to inform strategies for targeted emission reductions9,10.

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]. / Aktivnost' tsitoplazmaticheskikh NADP-zavisimykh degidrogenaz v pecheni krys v protsesse induktsii fenobarbitalom tsitokhroma P-450.

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.

[A chromatographic method of determining serotonin and histamine in a single sample of biological material]. / Khromatograficheskii metod opredeleniia serotonina i gistamina v odnoi probe biologicheskogo materiala.

Serotonin and histamine are important components of neurohumoral regulation. The biologic and fluorometric methods currently used for their measurements are labor-consuming and involve the use of unavailable reagents and expensive equipment. The authors suggest a sensitive simplified technique for serotonin and histamine measurements in a small volume of the biologic material (tissue and blood). The procedure is as follows: serotonin and histamine are isolated by thin-layer chromatography, the obtained samples are treated with alloxan in dimethyl formamide medium, and the stained solutions are examined in spectrophotometer. The suggested method is highly specific and sensitive, simple, makes use of Soviet equipment and of available reagents, this recommending it for clinical biochemical, as well as for experimental studies.

[Pulmonary microcirculation after distant gamma-therapy of breast and thyroid cancer (perfusion pulmoscintigraphy data)]. / Mikrotsirkuliatsiia v legkikh posle distantsionnoi gamma-terapii raka molochnoi i shchitovidnoi zhelez (po dannym perfuzionnoi pul'mostsintigrafii).

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]. / Rol' glitserofosfatnogo shunta v reguliatsii okisleniia tsitoplazmaticheskogo NADH i sinteza ATP mitokhondriiami pecheni v ontogeneze u krys.

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.