UDP-Gal: <Emphasis Type="Italic">N</Emphasis>-acetylglucosamine β 1–4 galactosyltransferase expressing live attenuated parasites as vaccine for visceral leishmaniasis

As compared to cutaneous leishmaniasis, vaccination against visceral leishmaniasis (VL) has received limited attention. In this study, we demonstrate for the first time that an UDP-Galactose: N-acetylglucosamine β 1–4 galactosyltransferase (GenBank Accession No. EF159943) expressing attenuated LD clonal population (A-LD) is able to confer protection against the experimental challenge with the virulent LD AG83 parasite. A-LD was also effective in established leishmania infection. The vaccinated animals showed both cell mediated (in vitro T-cell proliferation, and DTH response) and humoral responses (Th1 type). These results demonstrate the potential of the attenuated clones as an immunotherapeutic and immunoprophylactic agent against visceral leishmaniasis.     

Penetration and proliferation of BHK and HeLa cells into a three-dimensional collagen matrix of bone stroma type. Preliminary results

Some preliminary data regarding the test of penetration and proliferation of BHK and HeLa cells biocompatibility to a three dimensional stroma saturated with phosphorous and calcium salts (a biomaterial replacing bone) are presented. These data suggest that the analysed biomaterial might be used in surgical practices of prosthesis appliance on interfaces of fractured bone.     

Effect of pentobarbital on neuronal inhibitory response evoked in an isolated slab of cat auditory cortex by intracortical stimulation

Neuronal responses of an acutely isolated slab of auditory cortex (area AI) to intracortical electrical stimulation were studied intracellularly in cats anesthetized with pentobarbital. It was found that 77% of responses were primary IPSPs, and allowing for secondary inhibitory responses, an inhibitory response was observed in 92% of neurons. All types of neuronal responses in the slab were short-latency. The maximal response latency did not exceed 5 msec. Neurons responding to stimulation by IPSPs were found at all depths in the slab, with a maximum in layers II–III. Nearly all primary IPSPswere mono- and disynaptic. Pentobarbital increased the duration of individual neuronal inhibitory responses in the isolated slab of auditory cortex without affecting maximal duration of the IPSP. The mechanisms of the effect of pentobarbital on the amplitude and duration of IPSPs are discussed.I. I. Mechnikov Odessa State University. Translated from Neirofiziologiya, Vol. 16, No. 2, pp. 147–152, March–April, 1984.     

The production of hematopoietic growth factors by endothelial accessory cells

Monocytes are known to produce both hematopoietic growth factors and other factors, monokines, which do not directly stimulate hematopoiesis. Monokines such as interleukin-1 (IL-1) and tumor necrosis factor (TNF) may indirectly stimulate mesenchymal cells to produce hematopoietic growth factors. The identity of all the factors produced by monocytes or mesenchymal cells has not been established because of overlapping activities on biologic assay. The purpose of this study was to identify the individual growth factors produced by endothelial cells before and after stimulation with various monokines. We prepared conditioned media and extracted RNA from endothelial cells before and after stimulation with monokines. The results show that immortalized endothelial cells produce maximal detectable amounts of granulocyte-macrophage colony-stimulating factor (GM-CSF) constitutively. In contrast, GM-CSF production by primary endothelial cells requires induction with either IL-1 or TNF.     

Demographic genetic approach in anthropologic research. II. A method for calculating the coefficient of consanguinity in a complex nongraphic pedigree

A simplified method of manual calculation for inbreeding coefficient (and/or relationship) from complicated pedigree tables presented in a nongraphic mode is offered. The method is based on the use of positional dual codes of ancestors in which all genealogical links of the proband are reflected.     

Peculiarities of formation and development of initial stages of an impulse breakdown in argon

The experimental results on the formation and development of initial stages of an impulse breakdown in atmospheric-pressure argon at townsend and streamer breakdown mechanisms for different initial conditions are presented. A streamer channel is shown to be initiated by bright luminescence formed at the point of critical avalanche amplification at different distances from the cathode depending on overvoltage. Prebreakdown currents are experimentally measured for the townsend and streamer breakdown mechanisms and peculiarities of spark channel formation for these mechanisms are studied.     

Isolation, macromolecular properties, and combining site of a chito-oligosaccharide-specific lectin from the exudate of ridge gourd (Luffa acutangula)

A lectin specific for chito-oligosaccharides from the exudate of ridge gourd (Luffa acutangula) fruits has been purified to homogeneity by affinity chromatography. The lectin has a molecular weight of 48,000, an S(0)20,w of 4.06 S and a Stokes radius of 2.9 nm. Upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis, a single band corresponding to Mr of 24,000 was observed both in the presence and absence of beta-mercaptoethanol. The subunits in this dimeric lectin are, therefore, held together solely by noncovalent interactions. The lectin is not a glycoprotein, and secondary structure analysis by CD measurements showed 31% alpha-helix. The hemagglutinating activity of L. acutangula agglutinin was not inhibited by any of the monosaccharides tested. Among the disaccharides only di-N-acetylchitobiose was inhibitory. The inhibitory potency of chito-oligosaccharides increased dramatically with their size up to penta-N-acetylchitopentaose. The lectin has two binding sites for saccharides. The affinity of chito-oligosaccharides for L. acutangula lectin, as monitored by titrating the changes in the near UV-CD spectra and intrinsic fluorescence, increased strikingly with the number of GlcNAc units in them. The values of delta G, delta H, and delta S for the binding process showed a pronounced dependence on the size of the chito-oligosaccharides, indicating that the binding of higher oligomers is progressively more favored thermodynamically than di-N-acetylchitobiose. The thermodynamic data are consistent with an extended binding site in this lectin, which accommodates a tetrasaccharide.