Determination of Staphylococcus species-specific antigens by using erythrocyte reagents

Species-specific (Staphylococcus aureus and S. epidermidis) antigenic and antibody erythrocyte diagnosticums have been prepared. Various tests made with the use of these diagnosticums have demonstrated that the activity of specific antigens is higher in hydrochloric acid extracts than in trichloroacetic and phenolic ones; this activity is linked with undialyzed components and depends on the peculiar features of the strain.     

Specific features of humoral immunity in cryptogenic fibrosing alveolitis patients

Cryptogenic fibrosing alveolitis (CFA) is a severe autoimmune disease of unclear etiology and prognostically unfavorable. The complexity of the diagnostics of this disease makes it necessary to search for new methods; for this reason immunity in CFA patients must be studied. The study of humoral organ-specific, organ-unspecific and antibacterial immunity of CFA patients revealed that the latter differed from the members of the groups used for comparison by a higher frequency of positive reactions in EIA determinations of IgG antibodies to cytokeratin-8 and Moraxella catarrhalis antigens. In addition, only in CFA patients a high degree of correlation (r=0.88) between these results was established. This made it possible to propose to use these reactions for confirming the diagnosis of CFA and suggested the probable role of M. catarrhalis in triggering autoimmune reactions characteristic of this disease.     

Postvaccinal immunity and immunological aspects of Haemophilus influenzae carrier state in children of different age groups after the administration of "Act-HIB" vaccine

The article deals with H. influenzae (different serotypes) carrier state and immune response before and after the administration of the vaccine "Act-HIB" to children of different age groups. Children aged up to 1 year and over 1 year have been found to differ in the dynamics of carrier state and in the concentration of antibodies of different classes to the antigens of this infective agent, which makes it necessary to carry out their early immunization with a view to ensure their protection from H. influenzae infection.     

Evolution of spore release mechanisms in the saprolegniaceae (Oomycetes): evidence from a phylogenetic analysis of internal transcribed spacer sequences

Classical studies on spore release within the Saprolegniaceae (Oomycetes) led to the proposition that different mechanisms of sporangial emptying represent steps in an evolutionary transition series. We have reevaluated this idea in a phylogenetic framework using internal transcribed spacer sequences of four genera. These data were compared with the response to osmotic stress exhibited by each taxon. Saprolegnia emerges as the most basal genus, sister to Achlya, Thraustotheca, and Dictyuchus. Achlya and Thraustotheca are most closely related, while Dictyuchus appears to have evolved along a separate evolutionary lineage. The resulting phylogenetic framework is consistent with the idea that the mechanism of sporangial emptying exhibited by Saprolegnia represents the plesiomorphic condition from which the other mechanisms were derived independently. These alternative mechanisms of spore release may have resulted from a small number of mutations that inhibited axonemal development and altered the temporal and spatial expression of lytic enzymes that degrade the sporangial wall. Copyright 1998 Academic Press.     

Comparative immunoenzyme analysis of sera for the presence of antibodies to a preparation of Staphylococcus aureus teichoic acids and DNA

The comparative analysis of the titers of antibodies to the preparations of S. aureus teichoic acids and DNA in the sera of healthy donors and patients with infectious endocarditis and rheumatic carditis was made by means of ELISA. The sera of patients with infectious endocarditis and rheumatic carditis, in contrast to the sera of healthy donors, showed the presence of antibodies to DNA in 23.5-76.2% of cases. The correlation between the presence of antibodies to S. aureus teichoic acids and DNA in the sera of the patients was weakly pronounced.     

Rapid immunoenzyme analysis

A variant of the immunoenzyme assay, reducing the duration of the assay procedure by 3 hours in comparison with the standard technique, is presented. This rapid variant is sufficiently sensitive and reproducible.     

Enantioselective metabolism of primaquine by human CYP2D6

Given the threat of resistance of human malaria parasites, including to artemisinin derivatives, new agents are needed. Chloroquine (CQ) has been the most widely used anti-malarial, and new analogs (CQAns) presenting alkynes and side chain variations with high antiplasmodial activity were evaluated. Six diaminealkyne and diaminedialkyne CQAns were evaluated against CQ-resistant (CQ-R) (W2) and CQ-sensitive (CQ-S) (3D7) Plasmodium falciparum parasites in culture. Drug cytotoxicity to a human hepatoma cell line (HepG2) evaluated, allowed to calculate the drug selectivity index (SI), a ratio of drug toxicity to activity in vitro. The CQAns were re-evaluated against CQ-resistant and -sensitive P. berghei parasites in mice using the suppressive test. Docking studies with the CQAns and the human (Hss LDH) or plasmodial lactate dehydrogenase (Pf LDH) enzymes, and, a β-haematin formation assay were performed using a lipid as a catalyst to promote crystallization in vitro. All tested CQAns were highly active against CQ-R P. falciparum parasites, exhibiting half-maximal inhibitory concentration (IC50) values below 1 μΜ. CQAn33 and CQAn37 had the highest SIs. Docking studies revealed the best conformation of CQAn33 inside the binding pocket of Pf LDH; specificity between the residues involved in H-bonds of the Pf LDH with CQAn37. CQAn33 and CQAn37 were also shown to be weak inhibitors of Pf LDH. CQAn33 and CQAn37 inhibited β-haematin formation with either a similar or a 2-fold higher IC50 value, respectively, compared with CQ. CQAn37 was active in mice with P. berghei, reducing parasitaemia by 100%. CQAn33, -39 and -45 also inhibited CQ-resistant P. berghei parasites in mice, whereas high doses of CQ were inactive. The presence of an alkyne group and the size of the side chain affected anti-P. falciparum activity in vitro. Docking studies suggested a mechanism of action other than Pf LDH inhibition. The β-haematin assay suggested the presence of an additional mechanism of action of CQAn33 and CQAn37. Tests with CQAn34, CQAn37, CQAn39 and CQAn45 confirmed previous results against P. berghei malaria in mice, and CQAn33, 39 and 45 were active against CQ-resistant parasites, but CQAn28 and CQAn34 were not. The result likely reflects structure-activity relationships related to the resistant phenotype.