Genetic variability in East Asian dogs using microsatellite loci analysis.
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An analysis of eight microsatellite loci in 213 animals was performed to define the genetic structure and variability of 11 East Asian native dog populations. Allele diversity, observed heterozygosities, expected heterozygosities, F-statistics, G(ST) estimates, number of migrants per generation (Nm), and Nei's DA distance were calculated. Expected mean heterozygosities of Asian native dogs varied within a range of 0.310-0.718 with a mean value of 0.580. In a sample of 11 Asian dogs, the highest genetic diversity was exhibited in the Korean native dogs and the lowest in the Shiba, the Japanese native dog. All populations except the Kishu and Akita showed statistically significant deviation from Hardy-Weinberg equilibrium at more than one locus. After corrections for multiple significance tests, deviations over all loci were statistically significant in 7 of 11 dog populations, meaning that Asian dogs are genetically subdivided (global F(ST) = 0.154). Despite the locus-specific deviations, statistically significant departures from the Hardy-Weinberg equilibrium reflect deviations in the direction of heterozygote deficit, the global F(IS) being 0.072. In the neighbor-joining and unweighted pair group method with arithmetic mean (UPGMA) dendrograms based on Nei's DA distance, the Korean native breeds (the Sapsaree and the Jindo) were grouped together, then with the Eskimo dog. The two Japanese native dogs (the Hokkaido and the Akita) also clustered together, with moderate bootstrap support. In spite of some deviation, the three-dimensional scattergram based on principal components supported the conclusions suggested by the dendrograms based on Nei's DA distance. From these two analyses, the Korean native dogs formed the closest groups and then showed a close relationship to the Eskimo dogs, reflecting the fact that the Korean native dogs might be originated from dogs in the northern part of Far East Asia. (+info)
The cost barrier to peritoneal dialysis in the developing world--an Asian perspective.
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Countries in Asia vary significantly in culture and socioeconomic status. Dialysis costs and reimbursement structures are significant factors in decisions about the rates and modalities of renal replacement therapy. From our survey of Asian nephrologists conducted in 2001, a number of observations can be made. In many developing countries, the annual cost of continuous ambulatory peritoneal dialysis (CAPD) is greater than the per-capita gross national income (GNI). The median cost of a 2-L bag of peritoneal dialysis (PD) fluid is around US$5. The absolute cost of PD fluid among countries with significant differences in per-capita GNI actually varies very little. Thus, most renal failure patients can be expected to have problems accessing PD therapy in developing countries in Asia. In countries with unequal reimbursement policies for PD versus hemodialysis, a lack of incentive to prescribe PD also exists. Automated PD is nearly non existent in many developing countries in Asia. Some possible ways to reduce the cost barriers to PD in those countries include individual governments providing more public funding for treating dialysis patients; dialysate-producing companies reducing the cost of their products; physicians using appropriately smaller exchange volumes (3 x 2 L) in some Asian patients with smaller body sizes and with residual renal function; and reducing the complication rate for PD (for example, peritonitis) thereby reducing the costs required for treatment and hospitalization. (+info)
The molecular epidemiology of varicella-zoster virus: evidence for geographic segregation.
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Of 75 varicella-zoster virus (VZV) isolates obtained from patients in Africa, Asia, and the Far East, 74 (98.6%) were found to be positive for a BglI restriction site in gene 54. By contrast, <22% of strains from patients in the United Kingdom and in North and South America were positive for the BglI restriction site. Viruses positive for BglI were significantly more common in zoster occurring in patients of nonwhite origin (P<.05). Irrespective of the country in which the sample was obtained, 98% of strains positive for BglI clustered within a single phylogenetic group, which we termed "group A"; the exception was 1 strain that appeared to be recombinant genotype C/A. We used the BglI site to examine both the spread of type A viruses in the United Kingdom and the patterns of VZV infections within persons from different ethnic groups who grew up in the United Kingdom or abroad. (+info)
The emerging limbs and twigs of the East Asian mtDNA tree.
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We determine the phylogenetic backbone of the East Asian mtDNA tree by using published complete mtDNA sequences and assessing both coding and control region variation in 69 Han individuals from southern China. This approach assists in the interpretation of published mtDNA data on East Asians based on either control region sequencing or restriction fragment length polymorphism (RFLP) typing. Our results confirm that the East Asian mtDNA pool is locally region-specific and completely covered by the two superhaplogroups M and N. The phylogenetic partitioning based on complete mtDNA sequences corroborates existing RFLP-based classification of Asian mtDNA types and supports the distinction between northern and southern populations. We describe new haplogroups M7, M8, M9, N9, and R9 and demonstrate by way of example that hierarchically subdividing the major branches of the mtDNA tree aids in recognizing the settlement processes of any particular region in appropriate time scale. This is illustrated by the characteristically southern distribution of haplogroup M7 in East Asia, whereas its daughter-groups, M7a and M7b2, specific for Japanese and Korean populations, testify to a presumably (pre-)Jomon contribution to the modern mtDNA pool of Japan. (+info)
Biological activity of the Helicobacter pylori virulence factor CagA is determined by variation in the tyrosine phosphorylation sites.
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Helicobacter pylori is a causative agent of gastritis and peptic ulcer. cagA(+) H. pylori strains are more virulent than cagA(-) strains and are associated with gastric carcinoma. The cagA gene product, CagA, is injected by the bacterium into gastric epithelial cells and subsequently undergoes tyrosine phosphorylation. The phosphorylated CagA specifically binds SHP-2 phosphatase, activates the phosphatase activity, and thereby induces morphological transformation of cells. CagA proteins of most Western H. pylori isolates have a 34-amino acid sequence that variably repeats among different strains. Here, we show that the repeat sequence contains a tyrosine phosphorylation site. CagA proteins having more repeats were found to undergo greater tyrosine phosphorylation, to exhibit increased SHP-2 binding, and to induce greater morphological changes. In contrast, predominant CagA proteins specified by H. pylori strains isolated in East Asia, where gastric carcinoma is prevalent, had a distinct tyrosine phosphorylation sequence at the region corresponding to the repeat sequence of Western CagA. This East Asian-specific sequence conferred stronger SHP-2 binding and morphologically transforming activities to Western CagA. Finally, a critical amino acid residue that determines SHP-2 binding activity among different CagA proteins was identified. Our results indicate that the potential of individual CagA to perturb host-cell functions is determined by the degree of SHP-2 binding activity, which depends in turn on the number and sequences of tyrosine phosphorylation sites. The presence of distinctly structured CagA proteins in Western and East Asian H. pylori isolates may underlie the strikingly different incidences of gastric carcinoma in these two geographic areas. (+info)
Multicentre evaluation of the in vitro activity of linezolid in the Western Pacific.
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Multiresistance to antimicrobial agents is common in staphylococci and pneumococci isolates in the Western Pacific region. The activity of linezolid, a new oxazolidinone, was evaluated against a spectrum of Gram-positive species collected in the region. Eighteen laboratories from six countries in the Western Pacific examined the linezolid susceptibility of 2143 clinical isolates of Staphylococcus aureus, coagulase-negative staphylococci (CoNS) and Enterococcus spp. using broth microdilution or disc diffusion methodology. For Streptococcus pneumoniae (n = 351) and other streptococci (n = 83), Etest (AB Biodisk, Solna, Sweden) strips were used. Results were compared with other common and important antimicrobials. Linezolid-resistant strains were not detected among streptococci or staphylococci, including a significant proportion of S. aureus strains that were multiresistant. Almost all enterococci, including 14 vancomycin-resistant Enterococcus faecium, were linezolid susceptible. A small proportion of enterococci (0.8%) were intermediate to linezolid, and one strain of Enterococcus faecalis had a zone diameter of 20 mm (resistant). The linezolid MIC ranges (MIC(90)) of those strains tested by broth microdilution or Etest were: 1-4 mg/L (2 mg/L) for S. aureus, 0.5-4 mg/L (2 mg/L) for CoNS, 0.5-4 mg/L (2 mg/L) for Enterococcus spp., 0.12-2 mg/L (1 mg/L) for S. pneumoniae and 0.25-2 mg/L (1 mg/L) for Streptococcus spp. There was no difference in linezolid susceptibility between countries or between multiresistant and susceptible strains of each species monitored. (+info)
Features of evolution and expansion of modern humans, inferred from genomewide microsatellite markers.
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We study data on variation in 52 worldwide populations at 377 autosomal short tandem repeat loci, to infer a demographic history of human populations. Variation at di-, tri-, and tetranucleotide repeat loci is distributed differently, although each class of markers exhibits a decrease of within-population genetic variation in the following order: sub-Saharan Africa, Eurasia, East Asia, Oceania, and America. There is a similar decrease in the frequency of private alleles. With multidimensional scaling, populations belonging to the same major geographic region cluster together, and some regions permit a finer resolution of populations. When a stepwise mutation model is used, a population tree based on TD estimates of divergence time suggests that the branches leading to the present sub-Saharan African populations of hunter-gatherers were the first to diverge from a common ancestral population (approximately 71-142 thousand years ago). The branches corresponding to sub-Saharan African farming populations and those that left Africa diverge next, with subsequent splits of branches for Eurasia, Oceania, East Asia, and America. African hunter-gatherer populations and populations of Oceania and America exhibit no statistically significant signature of growth. The features of population subdivision and growth are discussed in the context of the ancient expansion of modern humans. (+info)
Blood pressure indices and cardiovascular disease in the Asia Pacific region: a pooled analysis.
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This article aims to compare the importance of systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), and pulse pressure (PP) as risk factors for stroke and ischemic heart disease and to assess whether the patterns are consistent by age and gender. Cox proportional-hazards regression, adjusted for cholesterol and smoking, was used to assess the associations of the 4 BP indices with stroke and ischemic heart disease by age and gender. The relative importance of individual indices was assessed with a hazard ratios for a 1-SD change in BP and by likelihood-ratio chi2 tests. The influence of >1 BP index in the Cox model was also estimated. The analyses demonstrated similar associations of SBP, DBP, and MAP with both fatal stroke and ischemic heart diseases, which were stronger than those of PP. Both SBP and MAP tended to be more important in the regression model than DBP or PP. In Cox models including DBP, addition of SBP improved the goodness of fit at all ages and for both genders. However, in Cox models including SBP, addition of DBP typically resulted in little incremental benefit over and above that of SBP alone. These data suggest that if time or resources are highly constrained, such as in much-needed epidemiologic surveys in developing countries, very little is lost from only measuring SBP. (+info)