Methodological bases for monitoring the health of the population

Bireplicon plasmids were constructed. The plasmids consist of DNAs of the streptomycete plasmid pIJ702, the Escherichia coli plasmid pUC19 and the phi C31 actinophage genome fragment encoding the function of the site-specific integration into the chromosome. Part of the plasmids transformed Streptomyces lividans TK64 to thiostreptone resistance. The DNA transforming activity depended on the mutual orientations of the blocks used for the construction and probably depended on the structural stability of the plasmids in S. lividans. The integrative vectors consisting of the pUC19 plasmid DNA and the phage genome fragment with the integrative function efficiently transformed S. lividans. No phage plagues were detected with the standard procedure of integrants' infection by phi C31 phage, despite the absence of the phi C31 phage repressor gene in the integrated DNA. The phi C31 phage mutants including clear and virulent ones were not capable of lytic growth on the integrants. The region determining the limitation of the phi C31 phage lytic development was localized by the deletion analysis of the bireplicon plasmids. As a result actinomycete monoreplicon plasmids were formed. The region is the 1.3 kb phage fragment whose right end maps at 0.2 kb preceding the right end of the phi C31 phage genome linear map.     

Characterization of VNFG, the delta subunit of the vnf-encoded apodinitrogenase from Azotobacter vinelandii. Implications for its role in the formation of functional dinitrogenase 2

The vnf-encoded apodinitrogenase (apodinitrogenase 2) from Azotobacter vinelandii is an alpha2beta2delta2 hexamer. The delta subunit (the VNFG protein) has been characterized in order to further delineate its function in the nitrogenase 2 enzyme system. Two species of VNFG were observed in cell-free extracts resolved on anoxic native gels; one is composed of VNFG associated with the VNFDK polypeptides, and the other is a homodimer of the VNFG protein. Both species of VNFG are observed in extracts of A. vinelandii strains that accumulate dinitrogenase 2, whereas extracts of strains impaired in the biosynthetic pathway of the iron-vanadium cofactor (FeV-co) that accumulate apodinitrogenase 2 (a catalytically inactive form of dinitrogenase 2 that lacks FeV-co) exhibit only the VNFG dimer on native gels. FeV-co and nucleotide are required for the stable association of VNFG with the VNFDK polypeptides; this stable association can be correlated with the formation of active dinitrogenase 2. The iron-molybdenum cofactor was unable to replace FeV-co in promoting the stable association of VNFG with VNFDK. FeV-co specifically associates with the VNFG dimer in vitro to form a complex of unknown stoichiometry; combination of this VNFG-FeV-co species with apodinitrogenase 2 results in its reconstitution to dinitrogenase 2. The results presented here suggest that VNFG is required for processing apodinitrogenase 2 to functional dinitrogenase 2.     

Hematologic and economic impact of aprotinin in reoperative pediatric cardiac operations

BACKGROUND: Aprotinin consistently reduces blood loss and transfusion requirements in adults during and after cardiac surgical procedures, but its effectiveness in children is debated. We evaluated the hemostatic and economic effects of aprotinin in children undergoing reoperative cardiac procedures with cardiopulmonary bypass. METHODS: Control, low-dose aprotinin, and high-dose aprotinin groups were established with 15 children per group. Platelet counts, fibrinogen levels, and thromboelastographic values at baseline and after protamine sulfate administration, number of blood product transfusions, and 6-hour and 24-hour chest tube drainage were used to evaluate the effects of aprotinin on postbypass coagulopathies. Time needed for skin closure after protamine administration and lengths of stay in the intensive care unit and the hospital were recorded prospectively to determine the economic impact of aprotinin. RESULTS: Coagulation tests performed after protamine administration rarely demonstrated fibrinolysis but did show significant decreases in platelet and fibrinogen levels and function. The thromboelastographic variables indicated a preservation of platelet function by aprotinin. Decreased blood product transfusions, shortened skin closure times, and shortened durations of intensive care unit and hospital stays were found in the aprotinin groups, most significantly in the high-dose group with a subsequent average reduction of nearly $3,000 in patient charges. CONCLUSIONS: In children undergoing reoperative cardiac surgical procedures, aprotinin is effective in attenuating postbypass coagulopathies, decreasing blood product exposure, improving clinical outcome, and reducing patient charges.     

Structural changes in the tissues of white rats after capsaicin administration

Attitudes to health and illness may differ between rural and urban dwellers. Issues that may relate to the provision of health services to rural dwellers are raised for consideration. The response of urban dwellers to illness or disability has often been linked to discomfort caused by pain or cosmetic attractiveness, while for rural dwellers the response to illness or disability is often related to the degree to which the illness or disability affects productivity. Often the rural resident will postpone seeking medical or associated services until it is economically or socially convenient. The notion of exposing their private lives to strangers or acquaintances from the local based services or to undertake the journey to distant services where the cultural or behavioural differences could be misunderstood, may impact on rural dwellers' well-being. Health service providers in rural areas need to understand such differences and difficulties when offering services.     

Comparative modeling of substrate binding in the S1' subsite of serine carboxypeptidases from yeast, wheat, and human

Human cathepsin A ("lysosomal protective protein"; E.C.3.4.16.5) is a multifunctional lysosomal protein which forms a high-molecular-weight complex with beta-galactosidase and alpha-neuraminidase, protecting them against intralysosomal proteolysis. In addition to this protective function, cathepsin A is a serine carboxypeptidase and the understanding of its catalytic function requires a definition of its substrate specificity. For this purpose, we used a combined experimental [Pshezhetsky, A. V., Vinogradova, M. V., Elsliger, M.-A., El-Zein, F., Svedas, V.K., & Potier, M. (1995) Anal. Biochem. 230, 303-307] and theoretical approach comparing cathepsin A to two different homologous carboxypeptidases of the same family: yeast carboxypeptidase Y and wheat carboxypeptidase II. We computed the energies involved in substrate binding to the S1' subsite (C-terminal) of cathepsin A using a structural model based on the X-ray structure of the homologous wheat carboxypeptidase II. The binding energies of N-blocked Phe-Xaa dipeptide substrates to the active sites of cathepsin A, wheat carboxypeptidase II, and yeast carboxypeptidase Y were estimated using a molecular mechanics force field supplemented with a solvation energy term. This theoretical analysis showed a good correlation with the experimentally determined free energies of substrate binding. This result validates the use of this approach to analyze the energetics of substrate binding to the S1' subsite and provides a rational interpretation of serine carboxypeptidase-substrate interactions in molecular terms. We conclude that the three serine carboxypeptidases have similar affinities for substrates with hydrophobic P1' amino acid residues but that the wheat enzyme has an additional capacity for binding positively charged P1' residues. Finally, the substrate specificity of human cathepsin A is very similar to that of carboxypeptidase Y, with a high binding affinity for substrates with hydrophobic P1' residues, but the affinity of cathepsin A for P1; Phe residue is higher than for the Leu residue.     

Interaction of ribosomes with membranes in vitro

Fluorescent "fusion-reporting" probe (R18) was used to study the interaction of ribosomes with membranes in vitro. The latter was incorporated both in the membranes, and ribosomes. The interaction of R18-labeled ribosomes with non-labeled liposomes (of different size and composition) or microsomes increased the fluorescence observed, i.e., the dilution of fluorescent probe took place. The dependence of interaction process on the change of liposomes indicates that the interaction between ribosomes and negatively charged liposomes was more efficient, than that with neutral ones. It is shown that ribosomes can interact with phospholipid membranes even after degradation of protein components accessible for proteins. The interaction of R18-labeled membranes with non-labeled ribosomes results in the increase of fluorescence too. Results obtained indicate to the possibility of direct interaction between ribosomes and membranes.