The hypothalamo-hypophyseal system in female rats with an anovulatory cycle

An electron-microscopic study was made of the suprachiasmatic and acurate nuclei of the hypothalamus, the intermediate and anterior lobes of the hypophysis in infertile female rats, sterilized by one injection of testosterone propionate in the critical period of their sexual development. Deformed synapses were detected on the bodies of the neurocytes of the suprachiasmatic nucleus, the accumulation of secretory granules and synaptoid vesicles in the nerve terminals of the intermediate lobe, and an intensive formation of secretion by the prolactin-producing adenocytes of the hypophysis. The mechanism of the masculinizing effect of androgens at the level of the hypothalamus and the possibility of correction of the anovulatory cycle in sterile females are discussed.     

Endothelial dysfunction in the development of vascular complications in diabetes mellitus

Patients with type 1 diabetes, aged 18 to 42 years, were compared to those aged 11 to 22 years. Activities of endothelial vasoactive factors and endothelial and leukocyte adhesion molecules were studied at different stages of development diabetes complications: nephropathy and retinopathy. The findings reveal role of the vasoactive factors in microangiopathy course.     

The development of neurocytes of the arcuate nucleus of the hypothalamus following whole-body gamma-irradiation of newborn rats

The results of karyometric and cytometric studies show that gamma-irradiation inhibits the growth and development of arcuate nucleus neurocytes of hypothalamus. The secretory function of neurocytes is also inhibited which is particularly important with regard to the formation of adenohypophysis functions as a major regulator of the adaptation response development. A radiation-induced disturbance of the latter aggravates the radiation injury to critical organs or systems of young animals thus influencing their viability.     

A search for association between the polymorphic markers of PON1 and PON2 genes and diabetic nephropathy in patients with type I diabetes mellitus

Alleles and genotypes of polymorphic markers of paraoxonase 1 and paraoxonase 2 genes (PON1 and PON2) encoding enzymes of the body antioxidative defense were compared in type 1 diabetes mellitus patients with or without diabetic nephropathy. The patients with nonoverlapping ("polar") phenotypes constituted different groups. The first group contained patients with diabetic nephropathy (DN+, n = 62), clinical proteinuria (albuminuria above 300 mg per day), and at least 15-year disease duration. In control group, the patients had no diabetic nephropathy (DN-, n = 68), their albuminuria was below 200 mg per day, and disease duration was at least 20 years. Comparative analysis with exact Fisher's test revealed no significant differences in frequencies of alleles and genotypes of the PON1 gene polymorphic marker Gln192Arg and of PON2 gene polymorphic markers Ala148Gly and Cys311Ser. Our results suggest that the polymorphic markers studied are not associated with diabetic nephropathy among Russian patients in Moscow.     

Effect of partial root excision on transpiration, root hydraulic conductance and leaf growth in wheat seedlings.

Removal of four out of five roots did not lower transpiration and stomatal conductivity of wheat (Triticum durum Desf.) seedlings. Water content of mature expanded leaf lamina remained constant at control levels. The results suggest that the only remaining root was capable to supply the shoot with water. This was evidenced by an increase in hydraulic conductivity of the root system following partial root excision measured at low subatmospheric pressures induced by vacuum. In the absence of a hydrostatic gradient, water flow from reduced root system was initially not higher than from an intact system, but increased subsequently. ABA content was increased in roots 1 h after partial root excision, which might contribute to the increase in hydraulic conductivity.     

The Role of Hormones in Fast Growth Responses of Wheat Plants to Osmotic and Cold Shocks

The effects of nutrient-solution cooling and PEG addition to the nutrient solution on the phytohormone content, the rate of leaf growth, leaf extensibility under the influence of external mechanical action, osmotic potential, and transpiration were studied in seven-day-old wheat plants. Leaf growth rapidly ceased, and the transpiration rate was reduced in both treatments. Growth cessation induced by PEG was transient, and growth resumption was preceded by an increase in the leaf extensibility. The functional role of auxin accumulation in plant shoots in the control of extensibility as well as the relationship between the ABA accumulation and a decrease in the cytokinin content, on the one hand, and reduced transpiration, on the other hand, under stress conditions are discussed.