Mapping the chicken genome: problems and perspectives

Various molecular methods are now used to map the chicken genome, including chromosome scraping, flow cytofluorimetry, zonal centrifugation, construction of chromosome-specific libraries, genetic analysis with polymorphic DNA markers, and in situ hybridization. Two main drawbacks are characteristic of existing maps of chicken chromosomes. First, classic genetic maps (i.e., linkage groups of genes for morphological, physiological, and biochemical characters), physical maps of chromosomes, and new genetic maps constructed on the basis of polymorphic DNA markers (RFLP, RAPD, VNTR, SSR, and CR1-PCR) do not coordinate with one another. Second, a relatively low number of genes is present in classic genetic maps and physical chromosome maps. Application of cytogenetic methods to chromosome mapping in birds is limited because of some specific features characteristic of the organization of avian genomes. For the same reason, studying the location and expression of avian genes is very important. Since mammalian and avian genomes differ in structure, revealing their possible common functional characteristics will provide for a better understanding of the general mechanisms that control biologically important characters in higher animals.     

Keratin 17 gene expression during the murine hair cycle

Treatment of rats with phenytoin (DPH), an anti-epileptic drug, results in lower tissue thyroid hormone (TH) levels and interferes with the metabolic pathway of TH. To test the hypothesis that DPH affects the enterohepatic cycle of TH and, thus, the kinetics of TH turnover, we performed a kinetic experiment (three-compartment analysis) and a steady-state, double-isotope equilibrium experiment in rats treated for 3 weeks with DPH (50 mg/kg body weight per day) and in untreated controls. This included measurements of TH and TH metabolite levels, as well as the activities of enzymes involved in the TH metabolic pathway. DPH treatment resulted in a decrease in the production of thyroxine (T4) (by 25%) and tri-iodothyronine (T3) (by 37%), a decrease in the T3 concentration in all three pools, and a redistribution of T4 from the fast to the slow pool. The amount of T4 increased in intestinal contents and feces by 66% and 71% respectively. Expressed as a fraction of daily TH disposal, fecal loss of T4 was enhanced from 10 to 23% and that of T3 from 16 to 21%. An increase in T4 and T3 UDP-glucuronyltransferase activities was observed, suggesting that the increased fecal loss of T4 and T3 is secondary to an increased biliary output of their glucuronides. The reduced secretion of TH and increased fecal clearance during DPH treatment can lead in the long run to depletion of TH stores.     

The classification of diseases of the temporomandibular joint

There were 2040 patients with temporomandibular joint (TMJ) diseases in the investigation including clinical, physiological, X-ray methods of research, contrast arthrotomography, computer arthrotomography and magnetic resonance tomography. The changes of structure in different lesions were estimated. The result of received data was elaboration of classification of TMJ internal derangements with estimation of clinical forms in according with structural changes and characteristics of syndromes.     

Tetracaine reports a conformational change in the pore of cyclic nucleotide-gated channels

Local anesthetics are a diverse group of clinically useful compounds that act as pore blockers of both voltage- and cyclic nucleotide-gated (CNG) ion channels. We used the local anesthetic tetracaine to probe the nature of the conformational change that occurs in the pore of CNG channels during the opening allosteric transition. When applied to the intracellular side of wild-type rod CNG channels expressed in Xenopus oocytes from the alpha subunit, the local anesthetic tetracaine exhibits state-dependent block, binding with much higher affinity to closed states than to open states. Here we show that neutralization of a glutamic acid in the conserved P region (E363G) eliminated this state dependence of tetracaine block. Tetracaine blocked E363G channels with the same effectiveness at high concentrations of cGMP, when the channel spent more time open, and at low concentrations of cGMP, when the channel spent more time closed. In addition, Ni2+, which promotes the opening allosteric transition, decreased the effectiveness of tetracaine block of wild-type but not E363G channels. Similar results were obtained in a chimeric CNG channel that exhibits a more favorable opening allosteric transition. These results suggest that E363 is accessible to internal tetracaine in the closed but not the open configuration of the pore and that the conformational change that accompanies channel opening includes a change in the conformation or accessibility of E363.     

The hemostatic system function of patients with severe forms of diphtheria

Hemostasis of 100 patients with severe diphtheria infection was studied throughout the disease. The patients were found to have marked procoagulant, anticoagulant and fibrinolytic disorders. Antithrombogenic activity of the vascular wall was also abnormal. The above impairments correlated with the symptoms severity and are interpreted as DIC syndrome which ran subclinically or as hemorrhagic syndrome. The majority of the patients underwent a hyperhypocoagulant phase of DIC syndrome.