Intragroup serotyping of meningococci

The method for obtaining antisera to meningococci of different serotypes are described and the scheme for the preparation of serotyping is presented, as well as the method for the preparation of the determinate fraction of serotype 2. Antisera to typing antigens 1, 2, 2-7, 2-10, 4, 5, 6, 8 (1) have been obtained, their specificity tested in parallel experiments with American and French typing sera. When typing meningococci, the use of antisera to purified protein antigen 2 is recommended.     

Epidemiological characteristics of meningococcal infection in Cuba

The results of the epidemiological analysis of the morbidity rate in meningococcal infection for 1976-1984 are presented. The maximum rise of morbidity rate, equal to 14.4 per 100000 of population, was observed in 1983. Primarily, the rise of morbidity rate in 1979 was induced by meningococci of two serogroups: C (44.6%) and B (36.4%). The vaccinal prophylaxis of the population, carried out in 1979 with the use of polysaccharide vaccine A + C, did not affect morbidity caused by group B meningococci. The isolation rate of these organisms reached 98.7% from patients and 81.0% from carriers. The characteristic feature of the epidemic process of meningococcal infection in Cuba was a considerable increase in the number of patients under 1 year of age and the absence of seasonal fluctuations in morbidity rate.     

The cytogenetic effects of 22-MeV neutrons

22-MeV neutrons affecting the culture of human peripheral blood lymphocytes have been studied for their cytogenetic peculiarities. Linear character of the dependence of chromosome aberrations yield within the dose range of 0.2-4.0 Gy is noted. Relative biological efficiency of 22-MeV neutrons reaches the highest values at low doses (18.8-2.4). Pair fragments and dicentrics prevail in spectrum of aberrations.     

Aminoglycoside-3'-phosphotransferase from Actinomyces fradiae. Its isolation, purification and properties]

Aminoglycoside phosphotransferase was isolated from the mycelium of Act. fradiae, the neomycin-producing organism, with paromomycin, neomycin and to a less extent ribostamycin being substrates of aminoglycoside-phosphotransferase. It was purified to homogenous state. The maximum activity of the enzyme preparations was observed at pH 7.7--7.8;KM for neomycin and paromomycin was about 20 micron and KM for ATP was 150 micron. Mg2+ ions were necessary for the enzyme activity. None of the divalent cations tested could replace the magnesium ions in the reaction of phosphorylation catalyzed by the enzyme. High sensitivity to the ionic strength of the buffer was characteristic of the enzyme. It lost about 80 per cent of the initial activity at a concentration of KC1 equal to 1.0 M. The molecular mass of the enzyme from the mycelium of Act. fradiae was determined by the method of gel-filtration through sefadex G-100. It was about 22,000. High stability was characteristic of the enzyme. The fingings indicate that aminoglycoside phosphotransferase from Act. fradiae differs from the described aminoglycoside-3'-phosphotransferases isolated from antibiotic resistant bacteria.     

Evaluation of the prophylactic effect of gamma globulin in meningococcal infection.

Results of two controlled epidemiological tests evaluating the prophylactic effect of gamma globulin of Monogolian and Soviet production against meningococcal infection are presented. Observations were carried out on children aged 3 months to 4 years, not attending children's establishments. The results of the observation revealed the following prophylactic effect of gamma globulin of Mongolian production in the first two months after administration: index of efficiency--5.0, coefficient of efficiency--80%, P greater than 0.01. The efficiency of the prophylactic effect of Soviet gamma globulin was limited to one month: the index of efficiency amounted to 5.3, the coefficient of efficiency to 82.2%, P greater than 0.01. The course of meningococcal infection in the children who had received gamma globulin was less severe than in the children of the control group. Lethal outcome was recorded only in the group of children who had not received gamma globulin. The duration of the prophylactic effect of gamma globulin was found to depend on the height of the titres of specific antibodies in the preparation. The preparations are recommended as prophylactic means for children aged from 3 months to 4 years in doses of 1.5 ml (one dose) in the foci of meningococcal infection.     

The hypothalamo-hypophyseal system in female rats with an anovulatory cycle

An electron-microscopic study was made of the suprachiasmatic and acurate nuclei of the hypothalamus, the intermediate and anterior lobes of the hypophysis in infertile female rats, sterilized by one injection of testosterone propionate in the critical period of their sexual development. Deformed synapses were detected on the bodies of the neurocytes of the suprachiasmatic nucleus, the accumulation of secretory granules and synaptoid vesicles in the nerve terminals of the intermediate lobe, and an intensive formation of secretion by the prolactin-producing adenocytes of the hypophysis. The mechanism of the masculinizing effect of androgens at the level of the hypothalamus and the possibility of correction of the anovulatory cycle in sterile females are discussed.     

Evaluation of the sanative action of rifampicin on the meningococcal carrier state]

The results of the epidemiological control experiment on the efficacy of rifampicin in sanation of meningococci carriers are presented. The preliminary study of rifampicin sensitivity of 41 freshly isolated nasopharyngeal meningococcal strains showed that the MIC of the drug for 63 per cent of the isolates was 0.04--0.1 gamma/ml. Sanation was performed for 2 days; 1.2 g of the drug was used during the treatment course. The results of examination of 91 meningococci carriers showed that 4 days after the sanation the specific weight of the persons isolating no meningococci was reliably higher in the experimental group than that in the control group. The coefficient of rifampicin efficiency was 70.8 per cent. 10 days after sanation the difference in the level of the carriers isolating no meningococci in the experimental and the control groups was statistically insignificant. Therefore, the carriers treated with the drug received temporary protection from the causative agent at an average for 1 week. Later on they could become carriers again. As a result of sanation no changes in the meningococcal sensitivity to rifampicin was observed.     

Molecular analysis of Gaucher disease: distribution of eight mutations and the complete gene deletion in 27 patients from Germany

Gaucher disease is the most common lysosomal storage disease with a high prevalence in the Ashkenazi Jewish population but it is also present in other populations. The presence of eight mutations (1226G, 1448C, IVS2+1, 84GG, 1504T, 1604T, 1342C and 1297T) and the complete deletion of the β-glucocerebrosidase gene was investigated in 25 unrelated non-Jewish patients with Gaucher’s disease in Germany. In the Jewish population, three of these mutations account for more than 90% of all mutated alleles. In addition, relatives of two patients were included in our study. Restriction fragment length polymorphism analysis and sequencing of PCR products obtained from DNA of peripheral blood leukocytes was performed for mutation analysis. Gene deletion was detected by comparison of radioactively labelled PCR fragments of both the functional β-glucocerebrosidase gene and the pseudogene. Among the unrelated patients, 50 alleles were investigated and the mutations identified in 35 alleles (70%), whereas 15 alleles (30%) remained unidentified. The most prevalent mutation in our group of patients was the 1226G (370^Asn→Ser) mutation, accounting for 18 alleles (36%), followed by the 1448C (444^Leu→Pro) mutation, that was found in 12 alleles (24%). A complete gene deletion was present in two alleles (4%). The IVS1+2 (splicing mutation), the 1504T (463^Arg→Cys) as well as the 1342C (409^Asp→His) mutations were each present in one allele (2%). None of the alleles carried the 84GG (frameshift), 1604A (496^Arg→His) or the 1297T (394^Val→Leu) mutation. This distribution is different from the Ashkenazi Jewish population but is similar to other Caucasian groups like the Spanish and Portuguese populations. Our results confirm the variability of mutation patterns in Gaucher patients of different ethnic origin. All patients were divided into nine groups according to their genotype and their clinical status was related to the individual genotype. Genotype/phenotype characteristics of the 1226G, 1448C, and 1342C mutations of previous studies were confirmed by our results. Received: 19 November 1996 / Revised: 29 January 1997     

Proteins of the Rpf (resuscitation promoting factor) family are peptidoglycan hydrolases

The secreted Micrococcus luteus protein, Rpf, is required for successful resuscitation of dormant "non-culturable" M. luteus cells and for growth stimulation in poor media. The biochemical mechanism of Rpf action remained unknown. Theoretical predictions of Rpf domain architecture and organization, together with a recent NMR analysis of the protein structure, indicate that the conserved Rpf domain has a lysozyme-like fold. In the present study, we found that both the secreted native protein and the recombinant protein lyse crude preparations of M. luteus cell walls. They also hydrolyze 4-methylumbelliferyl-beta-D-N,N',N'-triacetylchitotrioside, a synthetic substrate for peptidoglycan muramidases, with optimum activity at pH 6. The Rpf protein also has weak proteolytic activity against N-CBZ-Gly-Gly-Arg-beta-naphthylamide, a substrate for trypsin-like enzymes. Rpf activity towards 4-methylumbelliferyl-beta-D-N,N',N'-triacetylchitotrioside was reduced when the glutamate residue at position 54, invariant for all Rpf family proteins and presumably involved in catalysis, was altered. The same amino acid substitution resulted in impaired resuscitation activity of Rpf. The data indicate that Rpf is a peptidoglycan-hydrolyzing enzyme, and strongly suggest that this specific activity is responsible for its growth promotion and resuscitation activity. A possible mechanism of Rpf-mediated resuscitation is discussed.     

Cytogenetic effectiveness of the therapeutic beam of fast neutrons emitted by the cyclotron U-120

The data are reported on the effectiveness of the therapeutic fast neutron beam of the medicobiological complex U-120 (Institute for Nuclear Research, Academy of Sciences of Ukrainian SSR) as determined by the yield of chromosome aberrations in lymphocyte culture of human peripheral blood irradiated in the air and in the water phantom.