Interaction of divalent cadmium ions with nucleotides and native DNA

In normal embryos, mRNA encoding platelet-derived growth factor A (PDGF A) and the platelet-derived growth factor receptor alpha (PDGFR alpha) are found within and adjacent to the site of vertebral development, the sclerotome. These patterns of expression are consistent with PDGF action on the developing sclerotome and dermis. Homozygous Patch (Ph) mutant mouse embryos lack the receptor gene (Pdgfra) due to an extensive deletion at that locus. Consistent with the spatial pattern of Pdgfra expression, striking deformities are found in the spine and ribcage of Ph/Ph embryos. In particular, we show that late-gestation Ph/Ph embryos have occult spina bifida involving the entire spinal column. We have analyzed the progression of the axial defects in homozygous Patch embryos in detail. By late gestation it appears that the components of the vertebrae are present, yet the neural arches of the spine are misshapen. We propose that PDGF A is required for proper positioning of the neural arch condensation at all axial levels. Furthermore, since the neural tube appears to close normally, we suggest that spina bifida in the Ph homozygote is caused primarily by a somitic mesoderm abnormality rather than a neural tube defect.     

The use of physiotherapy and antibacterial preparations in urogenital infections

335 patients with obliterative diseases of arteries of the low extremities were examined. Results of motor rehabilitation depend on the severity of post-amputation defect of the extremity and functional condition of the stump. The lower is the level of the amputation the higher is the effectiveness of the rehabilitational measures. Ischemia of femoral stump springs up rarely but its course is mare severe than ischemia of the stump of the shin, which is confirmed by the data of clinical examination, investigation of biochemical parameters of the blood and mortality rate. For prophylaxis of ischemia of the stump it is suggested simultaneously with the amputation of the extremity to perform reconstructive procedures on the arteries, aimed at restoration of blood flow through the profound femoral artery. This policy provides the possibility to form a long functional stump of the extremity and to improve results of motor rehabilitation.     

Refinement of technique for cosmonaut's body radiation loading estimation using of orbital station dosimetric monitoring system

Proposed is a technique for estimation of radiation loading of cosmonauts' body from the data of the space station radiation monitoring system by bringing the objective to a linear mathematical model. Resulted matrix ratios allow to work out the challenge; test calculations illustrating efficiency of the proposed technique are included.     

CRITICAL PLANE APPROACHES IN HIGH-CYCLE FATIGUE: ON THE DEFINITION OF THE AMPLITUDE AND MEAN VALUE OF THE SHEAR STRESS ACTING ON THE CRITICAL PLANE

Critical plane approaches are useful methods when designing against long-term fatigue of machine components made from metals. Somewhat surprisingly, the very basic problem of the evaluation of the amplitude and mean value of the shear stress acting on the critical plane is still not resolved satisfactorily for non-proportional cyclic loading conditions. In the present paper, existing proposals for solving this problem are briefly reviewed and their weaknesses highlighted. Then it is shown, through particular examples, that application of these proposals can lead to ambiguous results. Therefore, new definitions of the amplitude and mean value of the shear stress acting on the critical plane are formulated here. These new definitions are free from any ambiguity because they are based on the construction of the unique minimum-circumscribed circle to the path described by the shear stress on the critical plane. The centre of this circle defines the mean shear stress, whereas its radius provides the corresponding shear stress amplitude. The algorithm yielding this minimum-circumscribed circle is presented in some detail.     

The effect of chenotherapy on the reservoir function of the gallbladder in cholelithiasis patients]

The effect of chenodeoxycholic acid (CDCA) on the reservoir function of the gallbladder was studied in 46 patients with cholesterol cholelithiasis. There was a dependence between a clear increase of filling of the gallbladder in patients treated by this method with subsequent sharp reduction of its size and development of dyspepsia and diarrhea. In 14 patients increase of the gallbladder against the background of chemotherapy was not authentic but no dyspeptic phenomena occurred. Thus, decompensation of the reservoir function of the gallbladder in patients with cholelithiasis against the background of chemotherapy are manifested by a significant increase of the gallbladder size with subsequent emptying of bile into the duodenum and development of collagenous diarrhea.     

Mutation of the conserved Gly94 and Gly126 in elongation factor Tu from Escherichia coli. Elucidation of their structural and functional roles

All guanine-nucleotide-binding proteins cycle between an inactive, GDP-bound and an active, GTP-bound conformation whereby they function as molecular switches. Elongation factor Tu from Escherichia coli is used as a model for defining residues important in the switch mechanism. Gly94 and Gly126 were separately mutated to alanine residues to study their role in the switch mechanism. The mutant proteins are denoted [G94A]EF-Tu and [G126A]EF-Tu, respectively. Both mutations affect the affinities for guanine nucleotides considerably, resulting in a decrease in the characteristic preference for GDP over GTP. Furthermore the [G94A]EF-Tu mutant possesses an increased GTPase activity. The aminoacyl-tRNA affinity is much reduced for [G94A]EF-Tu, as reflected in an increase of the dissociation rate constant for the ternary complex by a factor of 40. Surprisingly, however, both mutants in their GDP forms have a low, but significant affinity for aminoacyl-tRNA, which is not seen for the wild-type elongation factor Tu. The mutants only exhibit minor changes compared to the wild type with respect to in vitro translation of a poly(U) messenger.