[The role of the mediator and hormonal links of the sympathetic-adrenal system in the anxiolytic effect of close to physiological doses of L-thyroxine under stress]. / Znachenie mediatornogo i gormonal'nogo zven'ev simpatiko-adrenalovoi sistemy v realizatsii anksioliticheskogo effekta blizkikh k fiziologicheskim doz L-tiroksina pri stresse.

OBJECTIVE: To study an effect of small doses of L-thyroxine on the level of anxiety in animals under stress and to analyze the role of the mediator and hormonal links of the sympathetic-adrenal system in its implementation. MATERIAL AND METHODS: The study was performed on 78 white outbread male rats. Stress was modeled using the «time deficit¼ method. Chemical sympathectomy was performed by intraperitoneal injection of guanetidine at a dose of 30 mg/kg for 28 days. Bilateral adrenalectomy was performed according to the method of Y.M. Kabak. L-thyroxine was injected intragastrically for 28 days in small doses (1.5-3 µg/kg). The level of anxiety was determined in the «open field¼ test. The content of iodine-containing thyroid hormones (ICTH) in the blood serum was evaluated by the enzyme immunoassay. RESULTS: It has been found that stress activates thyroid function (an increase in the concentration of ICTH by 23-44%, p<0.01) and increases the level of anxiety in animals (an increase in the total resting time by 21%, p<0.05 and the resting time in periphery - by 25%, p<0.01). Chemical sympathectomy does not affect the growth of anxiety in rats who have undergone stress, whereas adrenalectomy contributes to its increase (an increase in the total resting time and the resting time in periphery by 15 and 14%, p<0.05). The injection of L-thyroxine minimizes the increase in the content of ICTH in the blood (by 16-27%, p<0.05) and has an anxiolytic effect under stress (prevents an increase in the total resting time and the resting time in periphery). Both chemical sympathectomy and, especially, adrenalectomy somewhat minimize, but do not completely prevent the implementation of the anti-anxiety effect of L-thyroxine under stress. CONCLUSION: In the formation of the anti-anxiety effect of ICTH, their central stress-limiting influence is important, limiting the mobilization of both the mediator and hormonal links of the sympathetic-adrenal system. The role of the latter in the implementation of the stress-protective effect of thyroid cancer is not decisive.

Increases in Future AR Count and Size: Overview of the ARTMIP Tier 2 CMIP5/6 Experiment.

The Atmospheric River (AR) Tracking Method Intercomparison Project (ARTMIP) is a community effort to systematically assess how the uncertainties from AR detectors (ARDTs) impact our scientific understanding of ARs. This study describes the ARTMIP Tier 2 experimental design and initial results using the Coupled Model Intercomparison Project (CMIP) Phases 5 and 6 multi-model ensembles. We show that AR statistics from a given ARDT in CMIP5/6 historical simulations compare remarkably well with the MERRA-2 reanalysis. In CMIP5/6 future simulations, most ARDTs project a global increase in AR frequency, counts, and sizes, especially along the western coastlines of the Pacific and Atlantic oceans. We find that the choice of ARDT is the dominant contributor to the uncertainty in projected AR frequency when compared with model choice. These results imply that new projects investigating future changes in ARs should explicitly consider ARDT uncertainty as a core part of the experimental design.

Clouds enhance Greenland ice sheet meltwater runoff.

The Greenland ice sheet has become one of the main contributors to global sea level rise, predominantly through increased meltwater runoff. The main drivers of Greenland ice sheet runoff, however, remain poorly understood. Here we show that clouds enhance meltwater runoff by about one-third relative to clear skies, using a unique combination of active satellite observations, climate model data and snow model simulations. This impact results from a cloud radiative effect of 29.5 (±5.2) W m(-2). Contrary to conventional wisdom, however, the Greenland ice sheet responds to this energy through a new pathway by which clouds reduce meltwater refreezing as opposed to increasing surface melt directly, thereby accelerating bare-ice exposure and enhancing meltwater runoff. The high sensitivity of the Greenland ice sheet to both ice-only and liquid-bearing clouds highlights the need for accurate cloud representations in climate models, to better predict future contributions of the Greenland ice sheet to global sea level rise.

[Effect of the thyroid status on the proteinases/inhibitors system under stress].

Тhe alarm-stage of stress reaction (аn hour after the stress of swimming of rats in a cage during an hour) is characterized by the stimulation of trypsinе-like activity (TLA) in the liver, and especially in the blood. At the resistance stage (48 hours after the stress) there is normalization of TLA in the blood and limitation of its growth in the liver. At the stage of exhaustion (an hour of stress during 10 days) the most significant increase of TLA in the liver and blood develops. Experimental hypothyroidism (25 mg/kg merkazolil within 20 days) per se causes a reduction of TLA, defines more pronounced stimulation of proteolysis in the alarm-stage, prevents its normalization at the resistance-stage, and promotes its excessive activation at the stage of exhaustion. Introduction of small doses of L-thyroxine (1.5-3.0 g/kg during 28 days) does not affect the system of proteolysis, limitis the increase of TLA at the alarm- and exhaustion stages, prevents its stimulation at the resistance-stage. The dependence of the changes in the proteases/inhibitors system under stress from the level of iodine-containing thyroid hormones in the blood is due to their influence on the activity of endogenous proteinase inhibitors (a1-antitrypsin and a2-macroglobulin) and on the permeability of lysosomes membranes.

Issues in renal nutrition for persons from the former Soviet Union.

Dietary practices differ greatly among individuals by race and ethnicity. The importance of these differences is accentuated in patients with end-stage renal disease, a population for whom dietary restrictions are often prescribed. In addition to the known variation in dietary practices among US-born whites and African-Americans, persons of other ethnicities often present new and unique challenges to the dialysis-nutrition care team. The UCSF-Mt. Zion Dialysis Unit (San Francisco, CA) is a university-affiliated dialysis unit that serves an ethnically diverse population in San Francisco's Western Addition neighborhood. Ten percent to 15% of patients are recent immigrants from the former Soviet Union. This report highlights the dietary practices of this immigrant community and the need for ethnicity-specific renal nutrition recommendations in modern dialysis practice.

Role of thyroid hormones in stress-induced synthesis of heat-shock proteins in the myocardium.

Thyroxine in near-physiological doses increased the content of heat-shock proteins in the myocardium and stimulated their accumulation during immobilization stress. Blockade of thyroid functions with methimazole decreased the content of heat-shock proteins in rat myocardium during stress and heat shock and prevented their accumulation during adaptation to short-term immobilizations.

Influence of the thyroid status of the organism in the realization of the adaptational effect of cold.

The combined three- and six-hour effect of immobilization and cold on euthyroid rats induces suppression of the contractile function and functional reserve of the heart, the death, respectively, of 30 and 80% of the animals, hypothermia, changes in the weight of the adrenals and the spleen, and ulceration of the mucosa of the stomach. Stressing of the hypothyroid rats is accompanied by a substantially more pronounced decrease in the indices of cardiac dynamics and the resistance of the organism after 3 h, and the death of 100% of the animals after 6 h. The periodic effect of cold on euthyroid rats leads to an increase in the strength and speed of contraction and relaxation of the myocardium, as well as to an increase in the relative weight of the spleen. During subsequent stressing, cold adaptation substantially limits the disturbances in contractile function and prevents the decrease in the functional reserve of the heart, increases survival, and decreases the degree of hypothermia, ulcer-formation, and change in the weight of stress-sensitive organs, while the preventive effect of cold adaptation is absent in the hypothyroid animals; this attests to the significance of thyroid status for its realization.