Continuous Normobaric Hypoxia Improved Cardiac Bioenergetics after Ischemia/Reperfusion: Role of Opioid Receptors.

We analyzed the role of opioid receptors in the conditioning effect of continuous normobaric hypoxia on bioenergetics of the heart subjected to ischemia/reperfusion injury. Male Wistar rats were adapted to a 21-day continuous normobaric hypoxia (12% pO2). Then, the hearts were isolated and subjected to 45-min total ischemia followed by 30-min reperfusion. Damage to the myocardium was assessed by activity of creatine phosphokinase in the perfusate. Experiments on isolated mitochondria showed that ischemia/reperfusion injury decreased the respiration rate in state 3 (V3), the ratio of added ADP and oxygen consumption in respiration state 3 (ADP/O ratio), the mitochondrial potential across the inner membrane (Δψ), and Ca2+ binding capacity of mitochondria. In addition, ischemia/reperfusion injury decreased myocardial ATP. Preventive continuous normobaric hypoxia pronouncedly moderated these adverse effects of reperfusion. It was found that its protective effects were related to activation of cardiac µ- and δ2-opioid receptors.

Studying the General Toxicity and Cumulative Properties of a Radiopharmaceutical Nanocolloid, (99m)Tc-Al2O3.

We studied toxicity of a new Russian radiopharmaceutical Nanocolloid, (99m)Tc-Al2O3. Tests for acute toxicity showed that this agent belongs to a class of moderate-toxicity substances and does not have cumulative properties. The evaluation of subchronic toxicity after subcutaneous injection of this product to rats (0.04, 0.2, and 0.4 ml/kg) and rabbits (0.02 and 0.2 ml/kg) for 7 days did not reveal changes in the general state, temperature, body weight, indices of the peripheral blood and bone marrow, functions of the heart, liver, kidneys, and nervous system, and morphological characteristics of the internal organs in animals. The drug does not produce a local irritant effect.

[STUDYING ACUTE TOXICITY OF NEW RADIOPHARMACEUTICAL 99MTC-AL2O3 NANOCOLLOIDS FOR ONCOLOGICAL DIAGNOSTICS].

The acute toxicity of a new drug based on nanocolloidal gamma alumina labeled with technetium-99m (99mTc) has been studied on 80 rats (40 females and 40 males) and 80 mice (40 females and 40 males) with intraperitoneal and subcutaneous drug administration. A single administration of the pharmacological agent was followed by observation of the survival of animals for 14 days with determining tolerable, toxic, and lethal doses for intraperitoneal and subcutaneous administration according to the Litchfield - Wilcoxon method, establishing the causes of animal death within 14 days of observation, and studying the drug influence on the general condition and some functional and morphological indices. Based on the established boundaries of toxicity and the classification of toxicity, the 99mTc-Al2O3 nanocolloids can be classified into conditionally moderately toxic substances. The actual values of LD5 of the radiopharmaceutical fall in the range of large doses. The safety factor for the drug studied significantly exceeds the minimum permissible value of 100.