[Morphological characteristic of apoptosis and its significance in neurogenesis].

On the basis of the literature data and the results obtained by the authors, modern concepts on the role of apoptosis in the regulation of a quantitative and qualitative constancy of the cells in the developing brain, is critically analyzed. The detailed description of morphological features and mechanisms of various phases of apoptotic death of neurons is given. Apoptosis affects the ordering of connections in the neural circuits and is involved in the pathogenesis of the neurodegenerative disorders - epilepsy, schizophrenia and Alzheimer's disease. The problem of the NO-ergic mechanism interaction with a cell in the apoptosis realization is examined. The data obtained support the view that NO should be considered as a cytotoxic factor inducing apoptosis. On the basis of ultrastructural features of postmitotic immature neurons, the presence of the apoptotic and necrosis-like (NO-dependent) ways of the natural cell loss during the differentiation process, is proposed.

[Role of nitric oxide in apoptosis of retinal neurons in human fetuses].

The localization of NADPH-diaphorase (NADPH-d), inducible NO-synthase (iNOS) and TUNEL-immunoreactive neurons was studied in the retina of human fetuses in the I-III trimesters of pregnancy. High NADPH-d activity was found in internal segments of photosensory cells, amacrine and ganglion cells. The population of NADPH-d-positive amacrine cells included three types of neurons. Neurons of the 1st type had large size and scarce dendritic field, occupying the inner nuclear and outer plexiform layers. Small neurons of the 2nd type were located in the inner plexiform layer. Ectopic amacrine cells of 3rd type could be found in the outer part of the ganglion cell layer. High density of the NADPH-d-positive neurons was detected in the central portion of retina surrounding fovea centralis and the optic disk area. The activity of NADPH-d was found to grow progressively in ontogenesis and to correlate with the appearance of immunoreactive iNOS in neurons. Immunoreactive iNOS marked a subpopulation of amacrine and ganglion cells which appeared in weeks 20-21 of gestation and attained maximal immunoreactivity by the end of the III trimester. TUNEL-immunoreactive nuclei of the neurons with the signs of the apoptotic destruction were found in weeks 30-31 of gestation. The highest apoptotic index was found in the population of ganglion cells. The data obtained strongly suggest that NO is a factor, mediating the neuronal apoptosis during the critical period of a differentiation of interneuronal connections in the human retina.

[Algorithms and computation methods of diagnostic coefficients in dynamic scintigraphy of skeleton and skeletal muscles]. / Algoritm i metodika rascheta nekotorykh diagnosticheskikh koéffitsientov pri dinamicheskoi stsintigrafii skeleta i skeletnykh myshts.

The paper is concerned with a program for data processing of dynamic scintigraphy of the skeleton and skeletal muscles using 99mTc-sodium 1-hydroxy-ethane-1, 1-diphosphonate. Employing gamma-chamber computer the program enables rapid and precise computation of the coefficient of RP elimination from the blood and the coefficients of RP accumulation by the bones and muscle tissue. Based on those coefficients one can make diagnosis and follow the time-course of pathological changes occurring in the skeleton during endocrine diseases.