Recent influenza virus A infections in forensic cases of sudden unexplained death

Summary 84 forensic necropsy cases with a history of sudden unexpected death and where no acceptable cause of death was found at autopsy (= cases of sudden unexplained death, SUD) were found to have a significantly higher rate of influenza A (H 3 N 2) infection than did matched controls of the general population and a group of forensic necropsy cases with known cause of death (NON-SUD cases).By contrast, the group of SUD cases was found to have no significantly increased infection rate with influenza H 1 N 1 and B virus, parainfluenza viruses, RS virus, adenovirus, and cytomegalovirus.The influenza A associated SUD cases had a significantly higher rate of pathological and histological findings previously described for cases of primary viral pneumonia than did SUD cases without recent influenza A infection and NON-SUD cases.These findings suggest that virological examination of SUD cases could be helpful in order to determine the probable cause of death.A considerable portion of the influenza associated SUD cases occurred during interepidemic influenza periods. Therefore, such cases could be a useful source for monitoring the interepidemic spread of influenza virus.     

Antiviral immune responses modulate the nature of central nervous system (CNS) disease in a murine model of multiple sclerosis

Summary: In animals and in humans, T-cell therapy can cure advanced disseminated leukemia that would otherwise be fatal. The therapeutic effect of immune T cells is quantitative. As the dose of effector T cells is increased, survival is proportionately increased. Therefore, effective T-cell therapy is predicated on the ability to procure large numbers of immune effector T cells. By using cultured T cells, the number of immune T cells can be increased in vivo substantially above che level achievable by vaccination. The survival of cultured T ceils in vivo is dependent upon both the culture conditions used and the therapeutic regimens employed. Under appropriate conditions, cultured T ceils can proliferate in vivo in response to stimulation by antigen, distribute widely and survive long term to provide effector function and immunologic memory. Given that T cells recognize peptides. the need for immunization with tumor can be circumvented by immunization with peptide. Peptide-specific T cells and the progeny of single T-cell clones can provide the necessary cellular functions to eradicate disseminated murine leukemia. The ability of cloned T cells to similarly provide substantial measurable immunity in humans has been validated in clinical trials. By priming with peptides and by using established culture conditions, T-cell therapy can now be directed against virtually any antigen within the host T-cell repertoire. The major remaining question to be answered is which proteins and which peptides are the most suitable targets for T-cell therapy trials.     

Frictional forces when rectangular guiding arches with varying edge bevel are employed

In orthodontic treatment employing arch guided tooth movement, rectangular wires are usually used to achieve three-dimensional controlled tooth movement. In the intention to optimize sliding mechanics and to improve the comfort of patients, edge beveled rectangular orthodontic wires are offered by different manufacturers. The objective of the study presented was to investigate the influence of differing but defined wire roundings on sliding mechanics of canine retraction. Employing the 0.018″ slot system, 0.016″×0.022″ standard steel wires (Remaloy and Remanium, Dentaurum Comp.) were tested. Force loss due to friction during canine retraction was determined using the Orthodontic Measurement and Simulation System (OMSS). In the arch guided distalization of canines, the average loss of force caused by friction was determined to be approximately 50%. Comparing wires with different edge bevel, the rounded wire in contrast to the wire with sharpest edge configuration results in a reduction of friction. Even a moderate wire rounding of the 0.016″×0.022″ steel wire results in about 10% reduction in frictional losses. However, dynamic analysis of tooth movement with the OMSS shows that there is no further improvement of sliding mechanics using wires with edge bevel exceeding the standard rounding of rectangular wires. In contrast, a strong edge bevel may result in a considerable loss of leveling.     

Influence of the amino acid differences between the hemagglutinin HA1 domains of influenza virus H1N1 strains on their reaction with antibody

For influenza H1N1 strains, including some of their escape variants, the association of amino acid differences located at their hemagglutinin HA1 domains with their antigenic relationship was examined. The antigenic relationship was recorded in terms of the ratios of hemagglutination inhibition (HI) titers, the concentration of antibody molecules recognized by the virus, and the equilibrium constant of epitope-paratope interaction determined with heterologous virus compared to that found with homologous virus. The HI titers of antisera were found to depend primarily on the concentration of antibody molecules recognized by the virus and much less on the equilibrium constants. The avidity of antibody in sera raised against historically later strains with earlier strains was higher than vice versa. In contrast to the results obtained with antisera, the same concentration of monoclonal antibody directed to the Sb site of A/Brazil virus was recognized by both heterologous and homologous viruses, and the differences in HI titers observed were due to avidity changes only. Some of the amino acid differences located at each of the antigenic sites were found to be associated with a reduction in the HI titers and in the concentration of antibody molecules recognized by heterologous virus, whereas other differences in addition decreased the avidity of epitope-paratope interaction. Further amino acid differences decreased the avidity only. The strains tested differed also in their amino acids located outside the antigenic sites. However, an influence of these differences on the reaction of virus with antibody could not be evidenced. For the strains tested, the antigenic hemagglutinin drift occurred by reduction of the concentration of antibody molecules recognized by the virus and by avidity changes, which, in turn, were caused by exchanges of some key residues located at the antigenic sites.