Ancestral origins and worldwide distribution of the PRNP 200K mutation causing familial Creutzfeldt-Jakob disease.
Creutzfeldt-Jakob disease (CJD) belongs to a group of prion diseases that may be infectious, sporadic, or hereditary. The 200K point mutation in the PRNP gene is the most frequent cause of hereditary CJD, accounting for >70% of families with CJD worldwide. Prevalence of the 200K variant of familial CJD is especially high in Slovakia, Chile, and Italy, and among populations of Libyan and Tunisian Jews. To study ancestral origins of the 200K mutation-associated chromosomes, we selected microsatellite markers flanking the PRNP gene on chromosome 20p12-pter and an intragenic single-nucleotide polymorphism at the PRNP codon 129. Haplotypes were constructed for 62 CJD families originating from 11 world populations. The results show that Libyan, Tunisian, Italian, Chilean, and Spanish families share a major haplotype, suggesting that the 200K mutation may have originated from a single mutational event, perhaps in Spain, and spread to all these populations with Sephardic migrants expelled from Spain in the Middle Ages. Slovakian families and a family of Polish origin show another unique haplotype. The haplotypes in families from Germany, Sicily, Austria, and Japan are different from the Mediterranean or eastern European haplotypes. On the basis of this study, we conclude that founder effect and independent mutational events are responsible for the current geographic distribution of hereditary CJD associated with the 200K mutation. (+info)
Production and detailed characterization of biologically active olive pollen allergen Ole e 1 secreted by the yeast Pichia pastoris.
The glycoprotein Ole e 1 is a significant aeroallergen from the olive tree (Olea europaea) pollen, with great clinical relevance in the Mediterranean area. To produce a biologically active form of recombinant Ole e 1, heterologous expression in the methylotrophic yeast Pichia pastoris was carried out. A cDNA encoding Ole e 1, fused to a Saccharomyces cerevisiae alpha-mating factor prepropeptide using the pPIC9 vector, was inserted into the yeast genome under the control of the AOX1 promoter. After induction with methanol, the protein secreted into the extracellular medium was purified by ion-exchange and size-exclusion chromatography. The structure of the isolated recombinant Ole e 1 was determined by chemical and spectroscopic techniques, and its immunological properties analysed by blotting and ELISA inhibition with Ole e 1-specific monoclonal antibodies and IgE from sera of allergic patients. The allergen was produced at a yield of 60 mg per litre of culture as a homogeneous glycosylated protein of around 18.5 kDa. Recombinant Ole e 1 appears to be properly folded, as it displays spectroscopic properties (CD and fluorescence) and immunological reactivities (IgG binding to monoclonal antibodies sensitive to denaturation and IgE from sera of allergic patients) indistinguishable from those of the natural protein. This approach gives high-yield production of homogeneous and biologically active allergen, which should be useful for scientific and clinical purposes. (+info)
Ti plasmids from Agrobacterium characterize rootstock clones that initiated a spread of crown gall disease in Mediterranean countries.
Crown gall caused by Agrobacterium is one of the predominant diseases encountered in rose cultures. However, our current knowledge of the bacterial strains that invade rose plants and the way in which they spread is limited. Here, we describe the integrated physiological and molecular analyses of 30 Agrobacterium isolates obtained from crown gall tumors and of several reference strains. Characterization was based on the determination of the biovar, analysis of 16S ribosomal DNA restriction fragment length polymorphisms by PCR (PCR-RFLP), elucidation of the opine type, and PCR-RFLP analysis of genes involved in virulence and oncogenesis. This study led to the classification of rose isolates into seven groups with common chromosome characteristics and seven groups with common Ti plasmid characteristics. Altogether, the rose isolates formed 14 independent groups, with no specific association of plasmid- and chromosome-encoded traits. The predominant Ti plasmid characteristic was that 16 of the isolates induced the production of the uncommon opine succinamopine, while the other 14 were nopaline-producing isolates. With the exception of one, all succinamopine Ti plasmids belonged to the same plasmid group. Conversely, the nopaline Ti plasmids belonged to five groups, one of these containing seven isolates. We showed that outbreaks of disease provoked by the succinamopine-producing isolates in different countries and nurseries concurred with a common origin of specific rootstock clones. Similarly, groups of nopaline-producing isolates were associated with particular rootstock clones. These results strongly suggest that the causal agent of crown gall disease in rose plants is transmitted via rootstock material. (+info)
Mutation analysis in patients of Mediterranean descent with Wilson disease: identification of 19 novel mutations.
In this study, we report further results of mutation analysis of the ATP7B gene in Wilson disease (WD) patients of Mediterranean origin. A total of 136 WD chromosomes, 73 of which were of Italian, 43 of Turkish, 18 of Sardinian, and two of Spanish origin, were analysed and the mutation characterised in 84.5% of them. We found 50 different mutations of which 19 are novel, including three nonsense, one frameshift, and 15 missense mutations. The mutations detected were rare and mostly found in the compound heterozygous state together with other mutations and only rarely in homozygosity. Most of these mutations lie in the transmembrane and ATP binding loop regions. These data expand our knowledge of both the structure-function relationships of the WD protein and the molecular pathology of WD, thus improving our capability of prevention and genetic counselling. (+info)
In 1988, the Regional Committee for the Eastern Mediterranean Region* (EMR) of the World Health Organization (WHO) adopted a resolution to eliminate poliomyelitis from the region by 2000. This report summarizes progress toward this goal in EMR countries through October 1999; all EMR countries, including war-torn and other underdeveloped areas of the region, are conducting essential polio eradication strategies, and eradication activities to rapidly stop poliovirus transmission are under way in countries where polio is endemic. (+info)
Optimized PCR using patient blood samples for diagnosis and follow-up of visceral Leishmaniasis, with special reference to AIDS patients.
We developed a highly sensitive PCR method that enables the diagnosis and posttherapeutic follow-up of visceral leishmaniasis with patient blood. The PCR assay was thoroughly optimized by successive procedural refinements to increase its sensitivity and specificity. It was compared to in vitro cultivation as well as to direct examination of bone marrow and to serology. Two hundred thirty-seven patients presenting with clinical signs compatible with visceral leishmaniasis were included in the study. Thirty-six were diagnosed as having Mediterranean visceral leishmaniasis (MVL). Twenty-three of them, including 19 AIDS patients, were monitored during and after treatment over a period from 2 weeks to 3 years. Our PCR assay proved more sensitive than in vitro cultivation, direct examination, and serology for all patients. It is simple and can be adapted to routine hospital diagnostic procedures. For the primary diagnosis of MVL, the sensitivity of PCR versus that of cultivation was 97 versus 55% with peripheral blood and 100 versus 81% with bone marrow samples. Regarding posttherapeutic follow-up, overall, 48% of positive samples were detected by PCR only. Seven patients presented with a clinical relapse during the study; six relapses were detected at first by PCR only, sometimes a few weeks before the reappearance of signs or symptoms. We conclude that an optimized and well-mastered PCR assay with a peripheral blood sample is sufficient to provide a secure diagnosis for all immunocompromised patients and most immunocompetent patients. We also suggest systematic posttherapeutic monitoring by PCR with peripheral blood for immunocompromised patients. (+info)
Modelling the incidence of congenital rubella syndrome in developing countries.
BACKGROUND: As of 1997, less than one-third of developing countries included rubella vaccine in their national immunization programme. In countries that have achieved high coverage of measles vaccine, an ideal opportunity exists to include control of rubella and congenital rubella syndrome (CRS) in enhanced measles control activities. Data on the burden of congenital rubella syndrome are important to guide rubella vaccination policies. METHODS: We reviewed the literature to identify studies of rubella antibody prevalence in developing countries that were conducted on populations with no major selection bias, prior to wide-scale rubella vaccination in the country. We used a simple catalytic model to describe the age-specific prevalence of susceptibility to rubella virus infection in given populations. Estimates of the incidence of infection among pregnant women were calculated using expressions for the average prevalence of susceptibility to infection and the incidence of infection during gestation. To estimate the number of cases of CRS, we assumed an overall risk of 65% after infection in the first 16 weeks of pregnancy and zero risk thereafter. These estimates were derived for each country for which data were available, then for each World Health Organization region, excluding Europe. RESULTS: The estimated mean incidence of CRS per 100,000 live births was lowest in the Eastern Mediterranean region (77.4, range 0-212) and highest in the Americas (175, range 0-598). The mean of the estimates of the total number of cases of CRS in developing countries in 1996 was approximately 110,000. The range was, however, very wide, from as few as 14,000 to as many as 308,000 cases. CONCLUSIONS: Congenital rubella syndrome is an under-recognized public health problem in many developing countries. There is an urgent need for collection of appropriate data to estimate the cost-effectiveness of a potential global rubella control programme. (+info)
From genotype to phenotype: genetics and medical practice in the new millennium.
The completion of the human genome project will provide a vast amount of information about human genetic diversity. One of the major challenges for the medical sciences will be to relate genotype to phenotype. Over recent years considerable progress has been made in relating the molecular pathology of monogenic diseases to the associated clinical phenotypes. Studies of the inherited disorders of haemoglobin, notably the thalassaemias, have shown how even in these, the simplest of monogenic diseases, there is remarkable complexity with respect to their phenotypic expression. Although studies of other monogenic diseases are less far advanced, it is clear that the same level of complexity will exist. This information provides some indication of the difficulties that will be met when trying to define the genes that are involved in common multigenic disorders and, in particular, in trying to relate disease phenotypes to the complex interactions between many genes and multiple environmental factors. (+info)