Evaluation of endothelial permeability in brain tumors by dynamic magnetic resonance tomography with magnevist contrast imaging on low-field MR-tomograph

In order to study the endothelial permeability to hydrophilic macromolecules in brain tumors we have developed a technique based on Gjedde-Rutland-Patlak approach to dynamic MRI study with Gd-DTPA injected intravenously, performed with low-field MRI tomograph Magnetom Open (Siemens medical). 27 patients with various brain tumors were referred for the study. The indices of Gd-DTPA transport to tumor tissue (KGd-DTPA) vary substantially, depending on the degree of malignancy and deliver essential information on microvascular permeability of tumor capillary bed.     

Littoral cells of the lymph node sinuses in venous congestion based on scanning electron microscopic data

The littoral cells of the sinuses in the popliteal lymph nodes have been studied in Wistar rats under physiological conditions of hemodynamics and 1 h after ligation of the caudal vena cava. Intercellular clefts (1-4 mcm wide) are demonstrated to exist between the littoral cells of the internal wall of the marginal sinus. Presence of fenestrae in the peripheral thinned areas of cytoplasm is specific for these cells. The diameter of the fenestrae is 60-1,000 nm however, the fenestrae with the diameter up to 100 nm predominate. Lining of the medullar sinuses is also characterized by a high content of fenestrae, the maximal diameter of the fenestrae being the same as in the marginal sinus, although most of the fenestrae have the diameter 50-500 nm. No open intercellular clefts between the littoral cells of the medullar sinuses are revealed. In some cases, penetration of lymphocytes through the lining of the sinuses is observed. Under venous congestion, the diameter and amount of the fenestrae, size and amount of open intercellular clefts in the lining of the lymphatic sinuses increase significantly. This demonstrates its increasing permiability, having an essential importance for compensation of circulatory disturbances in the zone of the venous congestion.     

Cytochrome P450 inactivation in microsomal membranes damaged by Fe2+-ascorbate-dependent lipid peroxidation

It has been established that Fe2+-ascorbate-dependent lipid peroxidation in rat liver microsome membranes is followed by the decrease of microsome cytochrome P450 content and the increase of the reduced haemoprotein inactivation rate. These changes are proportional to the amount of lipid peroxidation products (malonic dialdehyde) accumulating in the membranes.     

Cytogenetic consequences of hybridization between wild and laboratory mice

Wild mice from the aboriginal population were crossed with the laboratory C57BL/6 mice. F1 hybrids were backcrossed with both parents. Significant increase of recombination frequency in the AY-Ra region of the 2nd chromosome (from 22.0 to 33.1 cM), of the frequency of occurrence of X-Y univalents (up to 54.6%) and of autosomal univalents (up to 9.1%) was found in the F1. In backcrosses all these induces decreased gradually.     

Effect of emotional stress on the frequency of meiotic abnormalities in male mice

The effect of stress on the recombination frequencies at the 1st and 2nd chromosomes of male mice was shown earlier. The purpose of this work is the study of the stress effects on the behaviour of meiotic chromosomes. Male mice (A/He and DD/J inbred strains) were treated with acute immobilizing stress at different periods, prior to killing. It was shown that the stress significantly increases the frequency of X-Y and autosomal univalents in metaphase 1 and aneuploidy in metaphase 2. The most sensitive to the stress are the late interphase - early leptotene cells.     

A new species of the sclerorhynchid sawfish Borodinopristis from the Campanian (Upper Cretaceous) of North Carolina,USA

Elasmobranch fossils recovered from Campanian marine exposures at Elizabethtown, Bladen County, NC, include species from at least seven genera of sharks and four genera of batoids. Of particular interest is the recovery of multiple isolated rostral spines from a new sclerorhynchid sawfish, Borodinopristis shannoni, sp. nov. Species of Borodinopristis are known from oral teeth and/or rostral spines (‘rostral teeth’ for some authors). In species known from the latter, the spines differ from those of other sclerorhynchids by the presence of one or more ‘collared’ barbs on the posterior margin of the crown. Unlike the previously described B. schwimmeri, the rostral spines of the new species have well-developed hooked barbs with collars (curved, connected crests) extending asymmetrically onto the dorsal and ventral surfaces of the spine, as well as small, rudimentary barbs. Also unlike B. schwimmeri, the anterior margin of the spine is strongly convex and there is no enamelled collar at the base of the crown. The new species also occurs in the Upper Cretaceous of the Gulf Coastal Plain.     

B chromosomes of Korean field mouse Apodemus peninsulae (Rodentia,Murinae) analysed by microdissection and FISH

Organization of B chromosomes in the Korean field mouse Apodemus peninsulae was analyzed. We painted its metaphase chromosomes with whole and partial chromosome paints generated by microdissection and DOP-PCR. The results of the painting indicated that all B chromosomes contained a large amount of repeated DNA sequences. The repeats could be classified in terms of their homology and predominant location. Pericentromeric repeats of B chromosomes were present in many copies in pericentromeric C-blocks of all autosomes and in non-centromeric C-blocks of the sex chromosomes. B arm specific type 1 repeats comprised the main body of the arms of almost all B chromosomes and were present in the arms of A chromosomes as interspersed sequences. B arm-specific type 2 repeats were found at the ends of some B chromosomes that did not undergo compaction at the interphase- metaphase transition and remained uncondensed. On the basis of comparative analysis of localization of B chromosome repeats in the chromosomes of two related species, A. peninsulae and A. agrarius, we suggest a hypothesis of B chromosome origin and evolution in the genus Apodemus.     

Estimation of cardiac output from dynamic contrast multispiral tomographic data

OBJECTIVE: To describe and apply a method for programmatically calculating central hemodynamic parameters from the data of dynamic contrast X-ray computed tomography (CT). MATERIAL AND METHODS: A procedure is proposed to calculate cardiac output (CO) on the basis of the tracer dilution method as a ratio of the injected dose of a contrast agent (Urografin, Shering AG, Austria) to the area under the concentration-time curve derived for one of the cardiac chambers: [see text]. The blood concentration of the agent was estimated from the blood iodine (I) concentration-X-ray density (XD) regression dependence: [XD] = 0.49+22.07 x [I]. Thirty-three patients were studied on a multispiral X-ray Somatom Sensation 4 computed tomograph (Siemens), by injecting 15-20 ml of Urografin. The calculating method was realized as a software package for processing dynamic contrast CT data. RESULTS: The proposed method could exactly determine the values of cardiac output: the correlation with the results of the reference technique (Doppler echo measurement) was highly significant (r = 0.95; p < 0.001) in the whole range of values. Moreover, the data on XD could accurately determine the blood concentration of both iodine (I): [XD] = 0.49+22.07 x [I] and gadolinium as a component of the contrast paramagnetic Gd-DTPA for which the solution concentration-XR dependence was as follows: XD 1.2+33.6 x [Gd]. CONCLUSIONS: Thus, dynamic spiral CT may be also used for the estimation of cardiac output by the tracer dilution method.     

The leading role of mitochondrial depolarization in the mechanism of glutamate-induced disorder in Ca(2+)-homeostasis]

Digital fluorescence imaging techniques were employed to monitor changes in the cytoplasmic Ca2+ concentration and mitochondrial potential in fura-2 AM or rhodamine-123 loaded individual cerebellar granule cells during and following the Glu exposure. The data obtained suggests that the MD-induced blockade of the mitochondrial Ca2+ uptake and a reversal of the mitochondrial ATP-synthase play a critical role in the mechanism of the glutamate-induced disorder of neuronal Ca2+ homeostasis.     

Dynamics of changes in cell composition in the lymphoid tissue of somatic lymph nodes during total overheating of the body

At total overheating a manifested macrophagal reaction is observed in the rat somatic lymph nodes. Concentration of autoantigens in tissues increases, that results in transformation of small lymphocytes towards lymphoblasts and plasma cells. When manifested disorders of hemo- and lymphocirculation are present, eosinophils and mast cells, being tissue regulators of microcirculation and wall permeability of blood capillaries and lymphatic sinuses++., increase in number.