Genetic polymorphisms of cytochrome P450 2C9 causing reduced phenprocoumon (S)-7-hydroxylation in vitro and in vivo.

The effect of cytochrome P450 (CYP) 2C9 polymorphisms on the stereoselective biotransformation of the oral anticoagulant phenprocoumon (PPC) to inactive, monohydroxylated metabolites was studied in vitro and in vivo. In human liver microsomes, the (S)-7-hydroxylation--being the major metabolic pathway--was significantly compromised in a gene-dose-dependent manner in samples expressing the CYP2C9*2 or CYP2C9*3 allele. The CYP2C9*3/*3 genotype corresponded to an almost fourfold lower (S)-7-hydroxylation rate than CYP2C9*1/*1 (wild-type). The intrinsic clearance of human recombinant CYP2C9*2 and CYP2C9*3 for the (S)-7-hydroxylation was 28.9 and 50.9% lower than of CYP2C9*1, respectively. The area under the plasma concentration-time curve (AUC) of PPC metabolites after oral intake of 12 mg racemic PPC was significantly lower in volunteers expressing the CYP2C9*2 or CYP2C9*3 allele. Increasing plasma AUC metabolic ratios (parent compound/metabolite) in CYP2C9*2 and CYP2C9*3 variant allele carriers were found for each hydroxylation reaction and the CYP2C9*3/*3 genotype corresponded to an about 10-fold higher metabolic ratio of PPC (S)-7-hydroxylation relative to CYP2C9*1/*1. CYP2C9 polymorphisms cause a markedly compromised PPC (S)-7-hydroxylation. However, PPC metabolism appears overall less influenced by CYP2C9 genotype compared with other oral anticoagulants and it may thus be a valuable alternative for therapeutic anticoagulation of patients expressing CYP2C9 variant alleles.

Organic nitrates. II. Synthesis and biological activities of 4-nitrooxymethylphenyl-1,4-dihydropyridines.

Both 2-nitrooxymethyl-4-phenyl- (2) and 4-nitrooxymethylphenyl-1,4-dihydropyridines (3) represent new combinations of two different vasodilating structures. 2 could not be isolated due to its spontaneous lactonization. Derivatives of 3 were obtained via Hantzsch synthesis using nitrooxymethylated benzaldehydes. The inotropic potency in isolated porcine trabecular muscles and the vasodilator activity in isolated porcine coronary arteries of four nitrooxyphenyl-dihydropyridines were determined. Nitrendipine (NTD) and glyceryl trinitrate (GTN) were used for reference. 3 were negative inotropic, however, less than NTD and--except for the dicyano derivative 3d--more than GTN. Vasodilator properties were less pronounced than that of both nitrendipine and GTN. Vascular selectivity was low.

[A program for prevention of pseudomonas infections and immunoprophylaxis with PSAEVA vaccine]. / Program prevence pseudomonádových infekcí a imunoprofylaxe vakcínou PSAEVA.

The authors present three main trends of prevention of Gram-negative opportunistic infections investigated at the Cardiosurgical Clinic of the Institute of Clinical and Experimental Medicine. An important part is played by active and systematic surveillance with early signalling and analysis of new infections with subsequent aimed interventions against concrete sources of infection and mechanisms of transmission. It is necessary to think more of activation of endogenous infection the specific features of which make repression difficult and motivate investigations of preventive approaches. Rational antibiotic policy has so far not appreciated the danger of selection of endogenous and exogenous agents in standard situations where antibiotic therapy lacks an aimed and restrained approach. Immunoprophylaxis with the PSAEVA vaccine in the first preliminary controlled clinical investigation was characterized by the absence of nosocomial epidemics and septicaemia and a significant (fivefold) reduction of the incidence of non-pyocyanic Gram-negative bacteriaemia. The success of vaccination seems to be related to the anti-colonization and anti-invasive mechanism of specific and unspecific nature.

[A tonsillitis epidemic caused by adenoviruses]. / Epidemie angín vyvolaná adenoviry.

An epidemic of lacunar angina which affected, in relatively close common life, mostly only one of nine military units living in the same area. The failure of penicillin and negative finding of streptococci resulted in a retrospective establishment of the agent, which with all probability was adenovirus type 4. It has become obvious that the typical picture of lacunar or even pseudomembranous angina is not a reliable sign indicating streptococcal etiological even in a mass infection. The authors draw attention to the importance of continuous bacteriological surveillance even if only several cases of pharnygotonsillitis occur in a community. Uncertainties of the use of penicillin are then unnecessary in the therapy and even prophylaxis of the whole group, even if the first view may suggest its use. Some epidemiological features of the mass adenovirus angina are discussed.

Complex surveillance of streptococcus pyogenes. VI. Relationship between hypersensitivity to zymosan and indicators of immunity against group A streptococci.

A prospective study involving 20 volunteers was designed to test relationships between the sensitivity to zymosan and the indicators of nonspecific immunity against streptococci (inhibitory activity of blood and production of mediators). The immunization with Mannozym produced a conversion of zymosan-induced MIF with a subsequent improvement of immunity indicators in 4 out of 7 primovaccinated and 2 revaccinated subjects. This effect was detectable in some vaccines within 2-4 days after immunization and persisted for up to 5 months. Initially detected changes, their kinetics in the vaccinated subjects as well as time-related variations in the pattern of indicators during a one-year period of observation seem to suggest that there was a relationship between the natural and induced cellular sensitivity to zymosan and the inhibitory activity of blood. The inhibitory activity of blood was effectuated through enhanced mediator-induced phagocytic activity and nonspecific opsonin mechanisms. The mediators fluctuated in their values with time and were demonstrable in immunized subjects. There were observed interlinked reactions of cellular immunity with zymosan, peptidoglycan and streptococci. The mechanisms found are believed to constitute a fundamental, relatively easy-to-stimulate means of human immunity which may explain the experimental and epidemiological inconsistencies in the strictly type-specific interpretation of the M - anti-M system. Under in vitro conditions the effect of nonspecific immunization was bacteriostatic, but the role of these nonspecific mechanisms under conditions in vivo remains unclear. It is recommended that effectiveness of nonspecific immunization be verified under conditions of natural infection in man.

Complex surveillance of Streptococcus pyogenes V. Protective features complex surveillance of streptococcus of cell-mediated immunity against group a streptococci.

Exoproducts of incubated white blood elements from persons hypersensitive to zymosan were found to promote the phagocytic activity of human microphages (and guinea pig macrophages) under conditions of a combined model of "MIF-opsonophagocytic test". The stimulation resulted in a bacteriostatic effect, was non-type-specific and improved microphage potential to inactivate streptococci opsonized with anti-M antibodies in low titre. The microphages pre-exposed to anti-M sera remained unaffected, the effect was non-species-specific and nontype-specific and the stimulation resulted from the action of albumin fraction exoproducts. This seems to suggest that human mediators (lymphokines) may promote the activity of phagocytes. The cell-mediated immunity appears thus to have protective features even in the case of streptococci which are the typical extracellular parasites. The drawbacks of the model used, which make it difficult to quantify the found mechanism under in vivo conditions, are discussed in detail.

Studies on prophylactic efficacy of N-2-hydroxyethyl palmitamide (Impulsin) in acute respiratory infections. Serologically controlled field trials.

The results of three serologically controlled double blind field trials in army units are presented. The evaluation of results according to morbidity, regardless of aetiology, showed a significant reduction in acute respiratory diseases (ARD) after administration of Impulsin. In the 1973 trial (901 volunteers), 22.7% of ARD cases were found in the Impulsin group contrary to 34.4% in the placebo group (P less than 0.0002). The relevant values in the 1974 trial (610 volunteers) were 19.7% and 40.7% (P less than 0.002) and in the 1975 trial (353 volunteers) 10.6% and 28.8% (P less than 0.004). The study of the immunological background in representative sets of volunteers allowed determination of the aetiology, the proportion of asymptomatic infections and possible deformation of results due to preexisting protective antibodies. Manifestation rate (MR) expressing the proportion of sick persons out of all sensitive subjects with serologically proved infection was found useful. This indicator is relatively independent of randomization and is more sensitive as compared to the incidence rate. In the 1973 trial, influenza A 2 England was prevalent, the MR of infection being 15.4% in the Impulsin group and 44.9% in the placebo group (P less than 0.0002). After elimination of persons with preinfection antibodies greater than or equal to 1:256 the corresponding values of MR were 17.6% and 46.6% (P less than 0.005), reflecting the "relatively clean effect" of Impulsin. In the 1974 trial, where influenza B Hong-Kong was prevalent, MR was 14.3% and 57.1%, respectively (P less than 0.001). Preinfection antibodies were negligible. The preliminary prophylactic index of the drug seemed to be 4.3 for combined adenoviral infections (trials 1973 and 1974 taken together). In the 1975 trial, the results of serological examination were unsatisfactory. Antibodies vs. influenza A Port Chalmers were found in 24.5% of ARD only. The differnce is aetiologically unclarified ARD was statistically significant. Although displaying a significant limitation of clinical infections, the administration of Impulsin did not seem to have any influence on the formation of antibodies.

Complex surveillance of Streptococcus pyogenes. IV. The phenomenon of interference of human serum under the conditions of the bactericidal test.

The phenomenon of interference of human sera under the conditions of the bactericidal test was described. In the presence of these sera, secondarily non-resistant strains of Streptococcus pyogenes were capable of vigorous growth and anti M 12 bactericidal activity was impaired. The factor was found in the albumin fraction and has probably the character of a blocking cytophilic lymphokin. It can markedly distort the interpretation of the bactericidal test.

Complex surveillance of Streptococcus pyogenes. III. Immunological characteristics of streptococcal resistance in blood and new aspects of type nonspecific protection.

The influence of nonspecific immunity factors in indifferent human blood on the resistance of M non-typable field streptococci and collection M strains in the absence of anti-M antibodies was studied. The experimental results indicate that primary resistance is conditioned on balanced equipment of the strain with M protein and the nonspecific cofactor receptor [R]. Disbalanced strains were strongly phagocytized, with participation by nonspecific opsonins (complement C3 and nonspecific cofactor), irrespective of their M protein content. M + R--disbalance (selected collection strains) and M--R + disbalance (field strains on artificial media) were observed. The M and R resistance factor equipment of the streptococci probably represents plus and minus variants in the diverse process of the asymptomatic dissemination and pathogenic activity of streptococci in the human population. The given results are manifestly related to the general manner of existence of streptococci, to questions of conditional pathogenicity and to the concept of nonspecific defence against streptococci.

Complex surveillance of Streptococcus pyogenes. I. Immunological surveys of anti-M antibodies and possibilities of long-term epidemiological prognosis.

The results of complex surveillance of Streptococcus pyogenes, based on mass infections in the Czechoslovak army over a period of 11 years, are submitted. The epidemiological method revealed an incidence of cycles, lasting several years, of predominant pairs of T types, most of which could not be typed by their M protein. Auxiliary immunological surveys allowed the biological M activity of widespread strains to be estimated and probably form a basis for considerations on a negative long-term epidemiological type prognosis. The preliminary results presented offer prospects for a realistic methodological approach to the question of the type content of a future antistreptococcal vaccine.

Complex surveillance of Streptococcus pyogenes. II. Resistance in human blood and bactericidal activity receptors of field and collection streptococci.

A comparative study of a series of 31 epidemic streptococci and 36 collection M protein producers showed no statistically significant difference in their resistance in human blood. Even highly resistant field strains did not produce M protein (as the main bactericidal activity receptor) under laboratory conditions, however, although under natural conditions they left an anti-M response in the exposed population. Streptococcal resistance is not generally associated with M protein, but is influenced by another factor.