Genetic studies in relation to Kuru. VI. Evaluation of increased liability to Kuru in Gc Ab-Ab individuals.

The validity of the reported association between GcAb and kuru is analyzed. Phenotypes with one or more GcAb genes have an increased incidence of the disease at the expense of Gc 1-1 and Gc 2-2. Incidence ratios of kuru associated with various phenotypes examined over the linguistic groups studied indicate that only Gc Ab-Ab persons have a significantly greater chance of dying of kuru. The association X2 for the incidence ratio for those phenotypes possessing only one GcAb gene is significant, but there is significant heterogeneity between groups studied. Those of the Gc Ab-Ab phenotype are six times as likely to contract kuru as the baseline group. Criticisms of this analysis include difficulties defining an adequate control group in such heterogeneous populations, errors in determination of Gc phenotypes, inclusion of persons incubating kuru in the control groups, and questions of validity of statistical tests in isolated inbred populations.     

Haemagglutination-inhibiting antibodies to B.K. virus in Hungary.

Antibody inhibiting the haemagglutination by B.K. virus was found in 64% of the serum samples collected from 949 subjects in Hungary. The frequency of seropositivity was the lowest (17%) among infants 1 and 2 years of age and the highest (93%) in the age group 16 to 20 years. The subsequent age groups showed a slow continuous decline. The age-distribution curve drawn on the basis of the geometric means of titres has two peaks, one between 3 and 5 years of age and another between 21 and 30 years of age, reaching 6.74 and 7.05, respectively, as expressed in terms of log2 units. The prevalence of haemagglutination-inhibiting antibody to B.K. virus in Hungary and its distribution by age are similar to those reported from other European countries.     

Macrophages in resistance to candidiasis.

Candida albicans, an increasingly common opportunistic pathogenic fungus, frequently causes disease in immunodeficient but not immunocompetent hosts. Clarifying the role of the phagocytic cells that participate in resistance to candidiasis not only is basic to understanding how the host copes with this dimorphic pathogen but also will expedite the development of innovative prophylactic and therapeutic approaches for treating the multiple clinical presentations that candidiasis encompasses. In this review, we present evidence that a diverse population of mononuclear phagocytes, in different states of activation and differentiation and from a variety of host species, can phagocytize C. albicans blastoconidia via an array of opsonic and nonopsonic mechanisms and can kill C. albicans blastoconidia and hyphae by means of oxygen-dependent and -independent mechanisms. Reactive nitrogen intermediates should now be added to the well-established candidacidal reactive oxygen intermediates of macrophages. Furthermore, what were thought to be two independent pathways, i.e., nitric oxide and superoxide anion, have now been shown to combine to form a potent macrophage candidacidal molecule, peroxynitrite. In contrast to monocytes and neutrophils, which are important in resistance to early stages of C. albicans infections, more differentiated macrophages activated by cytokines such as gamma interferon participate in the acquired resistance of hosts with C. albicans-specific, cell-mediated immunity. Evidence presented in this review demonstrates that mononuclear phagocytes, in some instances in the absence of other professional phagocytes such as neutrophils, play an import role in resistance to systemic and mucosal candidiasis.     

Adaptation of protein metabolism to endurance training. Increased amino acid oxidation in response to training.

This study was conducted to investigate alterations in excretion of urea and total nitrogen after6-8 weeks of daily exercise and to establish if the capacity for amino acid oxidation in muscle is influenced by endurance training. Urea nitrogen excretion was increased in trained compared with untrained rats and nitrogen balance was less positive in trained than in untrained rats. Increased [14C]leucine oxidation with training was observed both in vivo and in vitro. The results of this study demonstrate that amino acid catabolism is increased during exercise training and that the muscle enzymes involved in leucine oxidation adapt to endurance training in a manner similar to the enzymes of carbohydrate and fat catabolism.     

Control of threonine pathway in E. coli. application to biotechnologies

Threonine is an essential amino acid for mammals and birds and an adequate supply is necessary for growth and maintenance. Its production has become the aim of metabolic bioengineering and genetic manipulations. We propose in this paper a rational approach for increasing threonine production in anE. coli strain based on metabolic control theory. We have derived a way to measure the control coefficients of threonine pathwayin vivo. The method consists in modelling the results of presteady-state experiments. Thein vivo concentrations and activities of the enzymes can then be measured and introduced into the model, so that thein vivo steady-state of the pathway can be evaluated. With such a model it is possible to calculate the theoretical values of the control coefficients of the threonine synthesis fluxin vivo.     

Reactions of fish to microorganisms in wastewater.

Fish were inoculated with various microorganisms present in wastewater. A threshold concentration was determined over which these microorganisms were recovered from the muscles. The threshold concentrations were different for bacteria, bacteriophages, and polio 1 LSc virus. The threshold values were lower when fish were inoculated than when they were immersed in water containing these organisms. Depuration experiments were efficient when the fish did not contain high concentrations of bacteria in their muscles. As the threshold concentrations are an expression of the capability of the immune system of the fish, these values can be useful for the design and management of fishponds in which treated wastewater is used.     

The sensitivity to P.T.C. in 541 Sardinians

The sensitivity of 541 Sardinians of both sexes to P.T.C. was examined using the complete Harris & Kalmus method.In the sample examined no significant differences on the basis of sex or age were noted. Even smoking did not seem to have a determinant influence on the sensitivity to P.T.C., but this was examined only indicatively.Subdividing the subjects examined on the basis of the area from which they came revealed significant differences between two of the three areas examined.     

Health in China. From Mao to market reform.

After the Liberation by Mao Ze Dong''s Communist army in 1949, China experienced massive social and economic change. The dramatic reductions in mortality and morbidity of the next two decades were brought about through improvements in socioeconomic conditions, an emphasis on prevention, and almost universal access to basic health care. The economic mismanagement of the Great Leap Forward brought about a temporary reversal in these positive trends. During the Cultural Revolution there was a sustained attack on the privileged position of the medical profession. Most city doctors were sent to work in the countryside, where they trained over a million barefoot doctors. Deng Xiao Ping''s radical economic reforms of the late 1970s replaced the socialist system with a market economy. Although average incomes have increased, the gap between rich and poor has widened.