Characteristics of the nitric oxide system indicators in the left ventricle myocardium in SHR

The aim was to determine the morpho-functional parameters of the left ventricular myocardium NO system in the rats with essential hypertension (SHR line). Material and methods. We used a combination of modern highly informative methods, namely: research of NOS isoform profie (nNOS, iNOS eNOS) in the myocardial slices along with an assessment of their synthesis and expression of the corresponding mRNA; NO derived nitrites level determination directly in the myocardium homogenates and concentration of nitrotyrosine in blood plasma of rats. The results of the performed studies have shown that high blood pressure in the SHR was accompanied by a signifiant increase in the concentrations of all three NOS isoforms in the myocardium and increased expression of their mRNA. Higher concentration of nitrites by 18.8 % was detected in the SHR group compared with the control animals. The concentration of nitrotyrosine in blood plasma of rats with essential hypertension was also increased by 25 %. Conclusions. The predominance of IRM to constitutive isoforms of NOS with low IRM content to iNOS was noted in the myocardium of the control group rats while in SHR rats higher IRM values were marked for all NOS isoforms. The formation of hypertension is accompanied by high content of NO end metabolites and the development of systemic nitroso-oxidative stress with the increase of nitrotyrosine concentration

The Beneficial Effects of Antifreeze Proteins in the Vitrification of Immature Mouse Oocytes

Antifreeze proteins (AFPs) are a class of polypeptides that permit organismal survival in sub-freezing environments. The purpose of this study was to investigate the effect of AFP supplementation on immature mouse oocyte vitrification. Germinal vesicle-stage oocytes were vitrified using a two-step exposure to equilibrium and vitrification solution in the presence or absence of 500 ng/mL of AFP III. After warming, oocyte survival, in vitro maturation, fertilization, and embryonic development up to the blastocyst stage were assessed. Spindle and chromosome morphology, membrane integrity, and the expression levels of several genes were assessed in in vitro matured oocytes. The rate of blastocyst formation was significantly higher and the number of caspase-positive blastomeres was significantly lower in the AFP-treated group compared with the untreated group. The proportion of oocytes with intact spindles/chromosomes and stable membranes was also significantly higher in the AFP group. The AFP group showed increased Mad2, Hook-1, Zar1, Zp1, and Bcl2 expression and lower Eg5, Zp2, Caspase6, and Rbm3 expression compared with the untreated group. Supplementation of the vitrification medium with AFP has a protective effect on immature mouse oocytes, promoting their resistance to chilling injury. AFPs may preserve spindle forming ability and membrane integrity at GV stage. The fertilization and subsequent developmental competence of oocytes may be associated with the modulation of Zar1, Zp1/Zp2, Bcl2, Caspase6, and Rbm3

DNA integrity and motility of human spermatozoa after standard slow freezing versus cryoprotectant-free vitrification

BACKGROUND: In contrast to the technique of conventional freezing, the vitrification of spermatozoa requires high cooling rates (720 000°K/min), which could be damaging for spermatozoa. The aim of our study was to compare slowly frozen and vitrified spermatozoa in terms of their post-thaw DNA integrity and motility. METHODS: Semen samples were prepared according to the routine swim-up technique and divided into aliquots for comparison of fresh, conventionally frozen and vitrified spermatozoa from the same ejaculate in the presence or absence of cryoprotectants. Spermatozoa motility and DNA integrity were determined. RESULTS: The motility of spermatozoa conventionally (slowly) frozen with a cryoprotectant was similar to that recorded for spermatozoa vitrified in the absence of cryoprotectant (47 versus 52%). The DNA integrity was unaffected by the cryopreservation method or presence of cryoprotectants. CONCLUSION: The vitrification of human spermatozoa in the absence of conventional cryoprotectants is indeed feasible. The DNA integrity of vitrified sperm is comparable with that shown by standard slow-frozen/thawed spermatozoa, yet the method is quick and simple and does not require special cryobiological equipment

The Specific Features of Oxygen Transport in the Acute Period of Ischemic Stroke

Objective: to study the oxygen transport system in the acute period of ischemic stroke (IS). Subjects and methods. Central hemodynamics and the oxygen transport system were studied, intracranial pressure was measured, cerebral perfusion pressure was calculated and neurophysiological and X-ray studies were conducted in 36 patients in the first 7 days of IS. Results. In the first 5 study days, circulatory hypoxia developed due to evolving hypodynamic circulation. Later on, the situation was deteriorated by arterial hypoxemia due to acute respiratory distress syndrome and increased pulmonary shunting. Simultaneously on days 5 and 7, there were reductions in the oxygen consumption index and oxygen extraction coefficient, which was due to vasoconstriction, higher blood flow velocity, and lower oxygen extraction. Neurophysiological evidence was used to diagnose sub- and decompensation of stem structural functions. Conclusion. Vasoconstriction leads to the development of circulatory hypoxia. Thus, the early period of ischemic stroke is marked by the decreased oxygen delivery index due to the development of hypodynamic circulation. This is further attended by pulmonary complications and microcircula-tory disorders. On day 5 of the acute period, noncardiogenic pulmonary edema developed and pulmonary shunt increased, by worsening hypoxia. Impaired function of stem structures due to their damage, as evidenced by clinical, neurophysiologi-cal, radiological, and autoptic studies, is one of the causes of hemodynamic disorders, thereby impairing the oxygen transport system. Key words: acute cerebral circulatory disorder, oxygen transport system