Proliferative and Differentiation Potential of Individual Clones Derived from Bone Marrow Stromal Precursor Cells

We present the results of a study on the proliferative and differentiation potential of individual clones of stromal fibroblasts growing in monolayer cultures of bone marrow cells. Each precursor cell yielding a large colony in primary culture is capable of up to 34 doublings in vitro. The transplantation of clones or monoclonal strains of stromal fibroblasts into the open system results in the formation of microenvironment consisting of the bone and reticular tissue and is suitable for the differentiation of all three lines of hemopoiesis. Evidence has been obtained that, in a closed system, individual clones are capable of differentiation into the bone, cartilaginous, and reticular tissues. In other words, the adult organism has a common cell precursor for these tissues.     

Modulation of airway caliber by deep inhalation in children.

To elucidate whether deep inhalation (DI) modulates changes in airway caliber in childhood, we measured the effect of DI on respiratory impedance before and after inhaled methacholine or salbutamol in 4- to 7-yr-old children (n = 15) suffering from recurrent wheezing. In all children, the real part of impedance between 12 and 16 Hz (Re[Z](12-16)) increased after methacholine from 5.6 +/- 1.2 to 8.2 +/- 1.6 cmH(2)O. l(-1). s (P < 0.001) and resonance frequency from 18 +/- 3 to 25 +/- 5 Hz (P < 0.001). These changes were partially reversed by DI: Re[Z](12-16) decreased to 7.2 +/- 1.2 cmH(2)O. l(-1). s (P < 0.01) and resonance frequency to 19 +/- 5 Hz (P < 0.001). In nine children, on a separate occasion, Re[Z](12-16) decreased after salbutamol from 8.3 +/- 1.9 to 5.1 +/- 0.9 cmH(2)O. l(-1). s (P < 0.001) and resonance frequency from 21 +/- 6 to 15 +/- 3 Hz (P < 0.05). The decrease of Re[Z](12-16) was partially reversed by DI (to 6.2 +/- 1.4 cmH(2)O. l(-1). s, P < 0. 01), but resonance frequency did not change significantly (P = 0.75). We conclude that in 4- to 7-yr-old children pharmacologically induced changes in airway caliber are modulated by DI. These findings suggest that airway-to-parenchyma interdependence is operative in this age range.     

Comparative analysis of mitochondrial DNA variation in four species of Far Eastern redfins of the genus Tribolodon (Pisces, Cyprinidae)

The variability of mtDNA in four Far Eastern endemic species of the genus Tribolodon was studied in the significant part of their areas. There was no close relationship between the lifetime and the level of mtDNA variability. The relation between the population genetic structure and the level of amphidromic species was revealed. The presence of mtDNA phylogroup differed in three of the four species shows that there was a long period of independent intraspecific divergent evolution in the history of these species. This period falls on aproximately the same historical age, and, apparently, is caused by one and the same factors. The period was not enough long and ended in the integration of genetically independent units into a single species.     

Craniometric differences between karyotypic races of the common shrew Sorex araneus (Mammalia) as a result of limited hybridization

The contact points of four karyotypic races (St. Petersburg, Moscow, Seliger and West Dvina) of the common shrew Sorex araneus L. were studied at the Valdai Hills (European Russia) in an area unimpeded by geographic barriers. The populations of the races are separated by narrow hybrid zones that represent the most complex heterozygous hybrid karyotypes. At these points of contact, the morphometric differentiation of karyotype races was examined in 12 cranial measurements in 190 shrews of a known karyotype. A comparison of the mean values in studied samples of immature shrews revealed statistically significant differences and the correlation of some measurements which describe the level of musculus temporalis. It has been proposed that morphometric differences in the karyotypic races were preserved and accumulated because of a 50% reduction of the frequencies of hybrids. The deviation from the Hardy-Weinberg ration in the frequencies of the genotype and haploid sets of chromosomes in the hybrid zones can be attributed to a number of fatalities of hybrid embryos or the nonrandom mating of karyotypic races. The ethological isolation might arise in the evolution of some karyotypic races from the reduced fitness of the hybrids.     

Characterization of chlorobenzoate degraders isolated from polychlorinated biphenyl-contaminated soil and sediment in the Czech Republic

Two polychlorinated biphenyl-contaminated sites in the Czech Republic, a soil at Zamberk and a sediment sludge at Milevsko, were screened for the presence of chlorobenzoate degraders. Sixteen different chlorobenzoate degraders were isolated from the soil compared with only three strains isolated from the sediment. From these strains, only four soil degraders and one strain isolated from the sediment, respectively, were shown to possess a complete chlorobenzoate (CB) pathway. Bacteria isolated from the soil have expressed more flexibility for CB degradation, namely in the case of ortho-chlorinated benzoates. They all possessed large plasmids, the restriction patterns of which were compared. Plasmids in Pseudomonas sp. A7, A8, A18 and A19, respectively, were cured and found to encode at least part of the metabolic pathway involved in the growth on ortho-chlorinated benzoates.     

Enzymatic synthesis of ATP from RNA and adenine

Summary The title compound was prepared by a three-stage enzymatic procedure consisting of (i) RNA hydrolysis to a mixture of ribonucleosides using intact mycelium of Spicaria violacea, (ii) transribosylation of exogenous adenine employing whole cells of Escherichia coli as a biocatalyst, and (iii) conversion of formed adenosine into ATP by the enzymes of alcohol fermentation and the kinases extracted from baker's yeast.     

Topography of carpal bone - An experimental model for carpal tunnel syndrome

By preparing a new experimental model for the carpal tunnel syndrome, the authors evaluated the differences of the human and rabbit carpal tunnels using a comparative anatomical study. A nearly identical situation-regarding the osseous and connective tissue formations in the carpal channel--was found. Therefore, the carpal tunnel of the rabbit is recommended for a model of chronic nerve compression, which is now planned by the authors.