Ultrastructural Signs of Regenerative-Degenerative Processes in Long-Term Dentate Fascia Grafts

An ultrastructural investigation of embryonic (E20) dentate fascia grafts transplanted into an acute cavity in the somatosensory neocortex of adult rats revealed a continuous dynamic state of the tissue nine months postgrafting. The grafts consisted mainly of typical granular cells with some admixture of hippocampal pyramidal neurons and polymorph hilar cells with a normal, mature ultrastructure. Many features of the transplanted tissue suggested continuing development and growth. Dendritic branches with growth tips, axonal growth cones, synaptic boutons with growth vesicles, immature myelin sheaths and myelin-producing cells were observed. In contrast, ultrastructural signs of degeneration were present in some axons, and, less often, in dendrites. These processes, as well as some of the terminal synapses, contained various amounts of lysosomes and lipofuscine granules. In many such terminals the signs of degenerative change were combined with the presence of multiple mitochondria, polymorph vesicles and tubular reticulum, indicating simultaneous reparative processes. It is suggested that continuous recycling of neuronal processes occurs in longterm dentate grafts. This morphological instability nay depend on the paucity of synaptic targets within the dentate tissue transplanted with a minimal quantity of hippocampal pyramidal cells and on the limitation of the afferent input. However, the observed features of the grafted dentate tissue are not qualitatively different from those observed in normal dentate with its protracted development and active compensatory reorganization

Stellar kinematics of X-ray bright massive elliptical galaxies

We discuss a simple and fast method for estimating masses of early-type galaxies from optical data and compare the results with X-ray derived masses. The optical method relies only on the most basic observables such as the surface brightness $I(R)$ and the line-of-sight velocity dispersion $\sigma_p(R)$ profiles and provides an anisotropy-independent estimate of the galaxy circular speed $V_c$. The mass-anisotropy degeneracy is effectively overcome by evaluating $V_c$ at a characteristic radius $R_{\rm sweet}$ defined from {\it local} properties of observed profiles. The sweet radius $R_{\rm sweet}$ is expected to lie close to $R_2$, where $I(R) \propto R^{-2}$, and not far from the effective radius $R_{\rm eff}$. We apply the method to a sample of five X-ray bright elliptical galaxies observed with the 6-m telescope BTA-6 in Russia. We then compare the optical $V_c$-estimate with the X-ray derived value, and discuss possible constraints on the non-thermal pressure in the hot gas and configuration of stellar orbits. We find that the average ratio of the optical $V_c$-estimate to the X-ray one is equal to $\approx 0.98$ with $11 \%$ scatter, i.e. there is no evidence for the large non-thermal pressure contribution in the gas at $\sim R_{\rm sweet}$. From analysis of the Lick indices H$\beta$, Mgb, Fe5270 and Fe5335, we calculate the mass of the stellar component within the sweet radius. We conclude that a typical dark matter fraction inside $R_{\rm sweet}$ in the sample galaxies is $\sim 60\%$ for the Salpeter IMF and $\sim 75 \%$ for the Kroupa IMF.Comment: accepted for publication in MNRA

Changes of some blood indices and myocardial electrolyte content during hypokinesia

Using special hypokinetic cages, the volume changes of circulating blood, its hematocrit and protein content, volume ratios between extra- and intracellular liquids in the body, as well as electrolyte content in the blood and myocardium during hypokinesia were investigated experimentally in rabbits

A Uniform Contribution of Core-Collapse and Type Ia Supernovae to the Chemical Enrichment Pattern in the Outskirts of the Virgo Cluster

We present the first measurements of the abundances of $\alpha$-elements (Mg, Si, and S) extending out to beyond the virial radius of a cluster of galaxies. Our results, based on Suzaku Key Project observations of the Virgo Cluster, show that the chemical composition of the intra-cluster medium is consistent with being constant on large scales, with a flat distribution of the Si/Fe, S/Fe, and Mg/Fe ratios as a function of radius and azimuth out to 1.4 Mpc (1.3 $r_{200}$). Chemical enrichment of the intergalactic medium due solely to core collapse supernovae (SNcc) is excluded with very high significance; instead, the measured metal abundance ratios are generally consistent with the Solar value. The uniform metal abundance ratios observed today are likely the result of an early phase of enrichment and mixing, with both SNcc and type Ia supernovae (SNIa) contributing to the metal budget during the period of peak star formation activity at redshifts of 2-3. We estimate the ratio between the number of SNIa and the total number of supernovae enriching the intergalactic medium to be between 12-37%, broadly consistent with the metal abundance patterns in our own Galaxy or with the SNIa contribution estimated for the cluster cores.Comment: accepted for publication in ApJ

Intracortical Dentate Fascia Grafts: Mossy Fiber Synapses in the Host Neocortex

Embryonic dentate fascia was grafted into a cavity in the area of the adult rat neocortex which represents the vibrissae (barrel field). We wished to test the possibility of development of connections between the two brain areas which do not have synaptic or tissue contacts in situ The unique characteristics of the giant synaptic boutons of the dentate mossy fibers were used for detection of the dentate synaptic contacts with neocortical neurons at the electron microscopic level. Ultrastructural analysis nine months postgrafting has shown that the bundles of mossy axons eter the host neocortex and develop multiple terminal and en passant contacts with typical characteristics. Neuronal perikarya, large dendritic trunks and fine caliber terminal dendritic branches were used by the mossy fibers as postsynaptic targets, as well as spines of various complexity and configurations. The subsynaptic dendrites seemed to be modified by synapsing giant boutons. Accumulation of cytoplasmic organelles was observed at these sites. Various bumps and protuberances were formed by the subsynaptic dendrite surface. The contents of these appendages were variable; some of them contained organeiles typical of dendroplasm, while others were more spine-like, often with inclusion of ribosomes. It is concluded that mossy fibers growing into the host neocortex can develop typical contacts with inappropriate targets with all the ultrastructural features of functional synapses

Moon as a character in the novel by M. Bulgakov “The Master and Margarita” (on metaphorization of activity)

Representation of certain natural realia in compositional-verbal structure of the novel “The Master and Margarita” by M. Bulgakov is studied. Peculiarities of representation by M. Bulgakov such natural phenomenon as the moon are analyzed, to which the author refers to the course of the novel. Predicative connections of this realia are described.Рассматривается изображение отдельных природных реалий в композиционно-речевой структуре произведения М. Булгакова «Мастер и Маргарита». Анализируются особенности изображения М. Булгаковым природной реалии «луна», к которой писатель обращается на протяжении всего романа. Рассматриваются также предикативные связи данной реалии

Morphometric Analysis of Hippocampal Pyramidal Neurons in situ and in Grafts Developing in the Anterior Eye Chambers of Young and Aged Wistar Rats

We performed a morphometric analysis of the somatic and nuclear areas in the pyramidal neurons of the hippocampal fields CA1 and CA3 in situ and in grafts developing for six weeks in the anterior eye chambers of young (3-to-9 wk.) and of aged (18-to-19.5 mos.) Wistar rats. The mean areas of the CA1 pyramidal somata and nuclei were significantly decreased in the aged animals in situ. The mean parameters of the CA3 pyramidal neurons were not changed, although their distribution was different (bimodal versus unimodal in the young animals). In both groups of recipients, the areas of CA1 neurons and of their nuclei were significantly larger in the grafted tissue than those found in situ. The areas of CA3 neurons did not show any difference in aged recipients and demonstrated only slight hypertrophy in young recipients. We concluded that the area sizes of the pyramidal cell bodies and nuclei in CA1 neurons are more sensitive than those of CA3 neurons to both aging and transplantation. The age of recipients did not significantly influence the growth and development of grafted pyramidal cells