Effects of HLA-DPB1 genotypes on chronic hepatitis B infection in Japanese individuals.

Significant associations of HLA-DP alleles with chronic hepatitis B (CHB) infection are evident in Asian and Arabian populations, including Japanese, Han Chinese, Korean, and Saudi Arabian populations. Here, significant associations between CHB infection and five DPB1 alleles (two susceptibility alleles, DPB1(*) 05:01 and (*) 09:01, and three protective alleles, DPB1(*) 02:01, (*) 04:01, and (*) 04:02) were confirmed in a population comprising of 2582 Japanese individuals. Furthermore, odds ratios for CHB were higher for those with both DPB1 susceptibility alleles than for those with only one susceptibility allele; therefore, effects of susceptibility alleles were additive for risk of CHB infection. Similarly, protective alleles showed an additive effect on protection from CHB infection. Moreover, heterozygotes of any protective allele showed stronger association with CHB than did homozygotes, suggesting that heterozygotes may bind a greater variety of hepatitis B-derived peptides, and thus present these peptides more efficiently to T-cell receptors than homozygotes. Notably, compound heterozygote of the protective allele (any one of DPB1*02:01, *04:01, and *04:02) and the susceptible allele DPB1*05:01 was significantly associated with protection against CHB infection, which indicates that one protective HLA-DPB1 molecule can provide dominant protection. Identification of the HLA-DPB1 genotypes associated with susceptibility to and protection from CHB infection is essential for future analysis of the mechanisms responsible for immune recognition of hepatitis B virus antigens by HLA-DPB1 molecules.

A functional SNP upstream of the beta-2 adrenergic receptor gene (ADRB2) is associated with obesity in Oceanic populations.

OBJECTIVE: Obesity is a growing health concern in the Oceanic populations. To investigate the genetic factors associated with adult obesity in the Oceanic populations, the association of single nucleotide polymorphisms (SNPs) of the beta-2 adrenergic receptor (ADRB2) gene with obesity was examined in 694 adults living in Tonga and Solomon Islands. RESULTS: A screening for variation in 16 Oceanic subjects detected 17 SNPs in the entire region of ADRB2, of which nine SNPs including two non-synonymous ones, rs1042713 (Arg16Gly) and rs1042714 (Gln27Glu), were further genotyped for all subjects. The rs34623097-A allele, at a SNP located upstream of ADRB2, showed the strongest association with risk for obesity in a logistic regression analysis adjusted for age, sex, and population (P=5.6 × 10(-4), odds ratio [OR]=2.5, 95% confidence interval [CI]=1.5-4.2). The 27Glu was also significantly associated with obesity in the single-point association analysis (P=0.013, OR=2.0, 95%CI=1.2-3.4); however, this association was no longer significant after adjustment for rs34623097 since these SNPs were in linkage disequilibrium with each other. A copy of the obesity-risk allele, rs34623097-A, led to a 1.6 kg/m(2) increase in body mass index (BMI; defined as weight in kilograms divided by height in meters squared) (P=0.0019). A luciferase reporter assay indicated that rs34623097-A reduced the transcriptional activity of the luciferase reporter gene by approximately 10% compared with rs34623097-G. An electrophoretic mobility shift assay demonstrated that rs34623097 modulated the binding affinity with nuclear factors. An evolutionary analysis implies that a G>A mutation at rs34623097 occurred in the Neandertal genome and then the rs34623097-A allele flowed into the ancestors of present-day humans. CONCLUSION: The present results suggest that rs34623097-A, which would lead to lower expression of ADRB2, contributes to the onset of obesity in the Oceanic populations.

Association analysis of susceptibility candidate region on chromosome 5q31 for tuberculosis.

Chromosome 5q31 spans the T helper (Th) 2-related cytokine gene cluster, which is potentially important in Th1/Th2 immune responses. The chromosome 5q23.2-31.3 has been recently identified as a region with suggestive evidence of linkage to tuberculosis in the Asian population. With the aim of fine-mapping a putative tuberculosis susceptibility locus, we investigated a family-based association test between the dense single nucleotide polymorphism (SNP) markers within chromosome 5q31 and tuberculosis in 205 Thai trio families. Of these, 75 SNPs located within candidate genes covering SLC22A4, SLC22A5, IRF1, IL5, RAD50, IL13, IL4, KIF3A and SEPT8 were genotyped using the DigiTag2 assay. Association analysis revealed the most significant association with tuberculosis in haplotypes comprising SNPs rs274559, rs274554 and rs274553 of SLC22A5 gene (P(Global)=2.02 x 10(-6)), which remained significant after multiple testing correction. In addition, two haplotypes within the SLC22A4 and KIF3A region were associated with tuberculosis. Haplotypes of SLC22A5 were significantly associated with the expression levels of RAD50 and IL13. The results show that the variants carried by the haplotypes of SLC22A4, SLC22A5 and KIF3A region potentially contribute to tuberculosis susceptibility among the Thai population.

Genome-wide SNP-based linkage analysis of tuberculosis in Thais.

Tuberculosis, a potentially fatal infectious disease, affects millions of individuals annually worldwide. Human protective immunity that contains tuberculosis after infection has not been clearly defined. To gain insight into host genetic factors, nonparametric linkage analysis was performed using high-throughput microarray-based single nucleotide polymorphism (SNP) genotyping platform, a GeneChip array comprised 59 860 bi-allelic markers, in 93 Thai families with multiple siblings, 195 individuals affected with tuberculosis. Genotyping revealed a region on chromosome 5q showing suggestive evidence of linkage with tuberculosis (Z(lr) statistics=3.01, logarithm of odds (LOD) score=2.29, empirical P-value=0.0005), and two candidate regions on chromosomes 17p and 20p by an ordered subset analysis using minimum age at onset of tuberculosis as the covariate (maximum LOD score=2.57 and 3.33, permutation P-value=0.0187 and 0.0183, respectively). These results imply a new evidence of genetic risk factors for tuberculosis in the Asian population. The significance of these ordered subset results supports a clinicopathological concept that immunological impairment in the disease differs between young and old tuberculosis patients. The linkage information from a specific ethnicity may provide unique candidate regions for the identification of the susceptibility genes and further help elucidate the immunopathogenesis of tuberculosis.

A genomic analysis of adult T-cell leukemia.

Adult T-cell leukemia (ATL) is an intractable malignancy of CD4+ T cells that is etiologically associated with infection by human T-cell leukemia virus-type I. Most individuals in the chronic stage of ATL eventually undergo progression to a highly aggressive acute stage. To clarify the mechanism responsible for this stage progression, we isolated CD4+ cells from individuals in the chronic (n=19) or acute (n=22) stages of ATL and subjected them to profiling of gene expression with DNA microarrays containing >44,000 probe sets. Changes in chromosome copy number were also examined for 24 cell specimens with the use of microarrays harboring approximately 50,000 probe sets. Stage-dependent changes in gene expression profile and chromosome copy number were apparent. Furthermore, expression of the gene for MET, a receptor tyrosine kinase for hepatocyte growth factor (HGF), was shown to be specific to the acute stage of ATL, and the plasma concentration of HGF was increased in individuals in either the acute or chronic stage. HGF induced proliferation of a MET-positive ATL cell line, and this effect was blocked by antibodies to HGF. The HGF-MET signaling pathway is thus a potential therapeutic target for ATL.

Sojourn times and substitution rate at overdominant and linked neutral loci.

The sojourn times until fixation of an overdominant allele were investigated based on the diffusion equation. Furthermore, the rate of accumulation of mutations, or the substitution rate, was predicted from the mean extinction time of a common overdominant allele. The substitution rate calculated theoretically agreed well with that determined by computer simulation. Overdominant selection enhances the polymorphism at linked loci, while its effect on the sojourn times and the substitution rate at linked loci has not been studied yet. To solve these problems, a model that assumed two linked loci, each with infinite alleles, was examined by computer simulation. A decrease in the recombination rate between two loci markedly changed the distribution of sojourn times of a neutral allele. Although overdominant selection obviously increased the sojourn times and the polymorphism at a linked locus, the rate of nucleotide substitution at the neutral locus was not influenced significantly even if complete linkage was assumed. These results suggest that, in regions containing overdominant genes, linked neutral loci will exhibit elevated levels of polymorphism, but their rate of molecular evolution remains that predicted by neutral theory.

DNA microarray analysis of natural killer cell-type lymphoproliferative disease of granular lymphocytes with purified CD3-CD56+ fractions.

Natural killer (NK) cell-type lymphoproliferative disease of granular lymphocytes (LDGL) is characterized by the outgrowth of CD3(-)CD16/56(+) NK cells, and can be further subdivided into two distinct categories: aggressive NK cell leukemia (ANKL) and chronic NK lymphocytosis (CNKL). To gain insights into the pathophysiology of NK cell-type LDGL, we here purified CD3(-)CD56(+) fractions from healthy individuals (n=9) and those with CNKL (n=9) or ANKL (n=1), and compared the expression profiles of >12 000 genes. A total of 15 'LDGL-associated genes' were identified, and a correspondence analysis on such genes could clearly indicate that LDGL samples share a 'molecular signature' distinct from that of normal NK cells. With a newly invented class prediction algorithm, 'weighted distance method', all 19 samples received a clinically matched diagnosis, and, furthermore, a detailed cross-validation trial for the prediction of normal or CNKL status could achieve a high accuracy (77.8%). By applying another statistical approach, we could extract other sets of genes, expression of which was specific to either normal or LDGL NK cells. Together with sophisticated statistical methods, gene expression profiling of a background-matched NK cell fraction thus provides us a wealth of information for the LDGL condition.

Serotonin-2 receptor-mediated regulation of release of acetylcholine by minaprine in cholinergic nerve terminal of hippocampus of rat.

5-Hydroxytryptamine (5-HT) inhibited the K+-induced release of [3H]acetylcholine [( 3H]ACh) from slices of the hippocampus of the rat, dose-dependently. Minaprine (3-(2-morpholinoethylamino)-4-methyl-6-phenylpyridazine, Fig. 1) had no effect on the release of [3H]ACh. However, it inhibited the (formula; see text) Fig. 1. Chemical structure of minaprine dihydrochloride. attenuation of the release of [3H]ACh by 5-HT dose-dependently. The 5-HT2 receptor antagonists, mianserine, methysergide and spiperone, prevented the inhibitory effect of the 5-HT, as well as did minaprine. The attenuating effect of 5-HT was not mimicked by the 5-HT1A receptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) and was not prevented by a 5-HT1A and 5-HT1B mixed receptor antagonist, propranolol, or by the 5-HT3 receptor antagonists, cocaine and metoclopramide. Minaprine inhibited the bindings of [3H]5-HT, [3H]8-OH-DPAT and [3H]ketanserin in the hippocampus. The inhibitory effect of minaprine on the binding of [3H]ketanserin was more marked than on the binding of [3H]5-HT and [3H]8-OH-DPAT, and was non-competitive. The Ki value of minaprine for the binding of [3H]ketanserin was 2.9 microM. The inhibitory effect of 5-HT on the release of [3H]ACh was observed in the presence of tetrodotoxin. By electrolytic lesioning of the medial septum, the K+-induced release of [3H]ACh from the slices of hippocampus was significantly reduced and the release was no longer inhibited by 5-HT. The lesioning significantly decreased the binding of [3H]ketanserin in the hippocampus, with hardly any reduction in the binding of [3H]5-HT and [3H]8-OH-DPAT.(ABSTRACT TRUNCATED AT 250 WORDS)

Genetic link between Asians and native Americans: evidence from HLA genes and haplotypes.

We have been studying polymorphisms of HLA class I and II genes in East Asians including Buryat in Siberia, Mongolian, Han Chinese, Man Chinese, Korean Chinese, South Korean, and Taiwan indigenous populations in collaboration with many Asian scientists. Regional populations in Japan, Hondo-Japanese, Ryukyuan, and Ainu, were also studied. HLA-A, -B, and -DRB1 gene frequencies were subjected to the correspondence analysis and calculation of DA distances. The correspondence analysis demonstrated several major clusters of human populations in the world. "Mongoloid" populations were highly diversified, in which several clusters such as Northeast Asians, Southeast Asians, Oceanians, and Native Americans were observed. Interestingly, an indigenous population in North Japan, Ainu, was placed relatively close to Native Americans in the correspondence analysis. Distribution of particular HLA-A, -B, -DRB1 alleles and haplotypes was also analyzed in relation to migration and dispersal routes of ancestral populations. A number of alleles and haplotypes showed characteristic patterns of regional distribution. For example, B39-HR5-DQ7 (B*3901-DRB1*1406-DQB1*0301) was shared by Ainu and Native Americans. A24-Cw8-B48 was commonly observed in Taiwan indigenous populations, Maori in New Zealand, Orochon in Northeast China, Inuit, and Tlingit. These findings further support the genetic link between East Asians and Native Americans. We have proposed that various ancestral populations in East Asia, marked by different HLA haplotypes, had migrated and dispersed through multiple routes. Moreover, relatively small genetic distances and the sharing of several HLA haplotypes between Ainu and Native Americans suggest that these populations are descendants of some Upper Paleolithic populations of East Asia.

5-HT2 antagonists and minaprine block the 5-HT-induced inhibition of dopamine release from rat brain striatal slices.

5-Hydroxytryptamine (5-HT) inhibited the K+-induced [3H]dopamine [( 3H]DA) release from slices of rat striatum. Minaprine (3-(2-morpholinoethylamino)-4-methyl-6-phenylpyridazine) attenuated the inhibitory effect of 5-HT in a dose-dependent manner. 5-HT2 receptor antagonists, ketanserin and mianserin, prevented the effect of 5-HT as well as minaprine did. The inhibitory effect of 5-HT was not mimicked by a 5-HT1A receptor agonist, 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), and was not prevented by a 5-HT1A and 5-HT1B mixed receptor antagonist, propranolol. Minaprine was a potent inhibitor of the binding of [3H]ketanserin to binding sites in the striatum over the concentration range 10(-6)-10(-4) M. Lesion of the medial forebrain bundle with 6-hydroxydopamine (6-OHDA) significantly reduced the K+-induced [3H]DA release from the striatum and release was no longer inhibited by 5-HT. Lesioning, however, did not change significantly the [3H]ketanserin binding in the striatum. These results suggest that minaprine suppresses the inhibitory effect of 5-HT on DA release in the striatum via the inhibition of 5-HT binding at the 5-HT2 receptor on the nerve terminal of the DA-ergic neuron and, further, that the proportion of the 5-HT2 receptor site which is located on the nerve terminal of the DA-ergic neuron is small in the striatum.

Effect of contact-lens-induced hypoxia on lactate dehydrogenase activity and isozyme in rabbit cornea.

Lactate dehydrogenase (LDH) levels and subunit isozyme patterns in cornea were monitored in 36 albino rabbits wearing thick, rigid, gas-permeable contact lenses for periods of 24 h, 2 and 7 days, and 1 and 3 months. The oxygen transmissibility of the contact lens was 15.3 x 10(-9) (cm/s) (ml O2/ml mm Hg). The activity of LDH in corneal tissue decreased according to the duration of lens wear. The LDH isozyme patterns shifted with lens wear from LDH1,2,3 (heart type, aerobic) to LDH4,5 (skeletal muscle type, anaerobic). The cornea swelled 8.8% with overnight contact lens wear, with increased swelling (11-12%) after further continuous lens wear. After contact lens removal, however, the LDH activity and the isozyme pattern returned to normal, and the corneal thickness quickly returned to normal. Based on these observations, it is suggested that LDH in rabbit corneas was physiologically affected by lens-induced hypoxia, but these changes were reversible. These results might further suggest that tear LDH levels in the human contact lens wearer could provide an ongoing assessment of the tolerance of the lens by the ocular surface.

Tear lactate dehydrogenase levels. A new method to assess effects of contact lens wear in man.

Lactate dehydrogenase (LDH) activity in tears was measured in 202 myopic rigid gas permeable (RGP) and 79 hydrogel human contact lens wearers and 48 normal controls by noninvasive microcapillary sampling. The oxygen permeabilities (Dk) of five selected RGP contact lenses ranged between 0 and 230 x 10(-11) (cm2/s) ml O2/ml mm Hg), and the water content (WC) of the hydrogel lenses was 38, 72, and 80%. When normal diurnal variation of tear LDH activity and tear sample volume (0.3-0.6 microliters) were carefully controlled, the tear LDH activity of RGP lens wearers in daily and extended wear correlated as an inverse function of Dk/L, with the highest enzyme activity observed in wearers of polymethylmethacrylate daily wear lenses (347.4 U/L). The tear LDH activity in Menicon EX (Dk 108) lens wearers was higher in the extended wear (192.7 U/L) than in the daily wear group (161.9 U/L). There was no significant difference in tear LDH activity between the Menicon SF-P (Dk 230) extended wear group (132.0 U/L) and controls (133.5 U/L). In the hydrogel lens daily wear group, tear LDH activity of Experimental 72 (WC 72%) and Experimental 80 (WC 80%) was higher than that of hydroxyethylmethacrylate (HEMA) despite having high Dk value. Experimental 80 extended wearers showed lower LDH activity in tears sampled between 0.3 and 0.6 microliters than that of HEMA wearers. These results suggest that sequential measurement of LDH levels in tears may offer a new and unique method for the assessment of the physiologic effects of contact lens wear on the ocular surface, and provide a new clinical paradigm for the interaction of the contact lens with the cornea.

Effects of increasing Dk with rigid contact lens extended wear on rabbit corneal epithelium using confocal microscopy.

The effects of 24-h wear of various Dk-rigid gas-permeable (RGP) contact lenses on the rabbit corneal epithelium were studied by in vivo tandem scanning confocal microscopy (TSCM), and confirmed by scanning electron microscopy (SEM). Lenses used were polymethylmethacrylate (PMMA) (Dk/L = 0), RGP experimental A lens (siloxanylmethacrylate-fluoromethacrylate-methylmethacrylate , 33), experimental B (siloxanylmethacrylate-fluoromethacrylate, 56), and experimental C (siloxanylstyrene-fluoromethacrylate copolymer, 64 x 10(-9)) (cm/s) (ml O2/ml mm Hg) with 0.15-mm thickness (Dk/L measured by polarograph including boundary layer effect). After 24-h PMMA lens wear, TSCM showed no superficial epithelial cells but only exposed, underlying wing cells. The cornea with experimental A showed partial superficial epithelial desquamation. With experimental B wear, slight superficial epithelial cell swelling and desquamation were observed on the surface of the cornea. No changes were observed for the eye with experimental C and control. The observed severity of desquamation of superficial epithelial cells was dependent on the oxygen transmissibility (Dk/L) of RGP lenses worn. All in vivo findings were confirmed by SEM observations. Based on the results of this study, we conclude that (a) although Dk/L = 56 lens B shows no residual overnight corneal swelling, surface damage is still produced; (b) Dk/L = 64 lens C is best for epithelium showing the same corneal images as control; and (c) TSCM is a good way to evaluate the contact lens safety and efficacy in vivo at the cellular level noninvasively.

Absence of association between the allele coding methionine at position 29 in the N-terminal domain of ICAM-1 (ICAM-1(Kilifi)) and severe malaria in the northwest of Thailand.

Intercellular adhesion molecule 1 (ICAM-1) is known to be the endothelial receptor for Plasmodium falciparum-infected erythrocytes. Associations of the variant allele coding methionine at position 29 in the N-terminal domain of ICAM-1, ICAM-1(Kilifi), with severe malaria have been investigated in African populations, and the results of these investigations have varied widely. In this study, we investigated a possible association between the ICAM-1(Kilifi) and severe malaria in adult malaria patients living in northwest Thailand. The frequencies of the ICAM-1(Kilifi) among patients with mild malaria, with non-cerebral severe malaria, and with cerebral malaria were 1.7%, 2.7%, and 2.3%, respectively. This variant showed neither positive nor negative association with severe malaria in Thailand.

Variation in malaria endemicity in relation to microenvironmental conditions in the Admiralty Islands, Papua New Guinea.

For 197 adults and adolescents in four villages of three small islands in the Admiralty Islands, Papua New Guinea, antimalarial antibody titers were examined using the indirect fluorescent antibody test (IFAT) and malaria parasites were detected by the microtiter plate hybridisation (MPH) method using polymerase chain reaction (PCR) technique. The parasite rate (either Plasmodium falciparum or P. vivax, or both) averaged 39.2%, varying from 31.1% to 44.8% among the four villages due to natural and artificial microenvironmental conditions related to breeding sites of mosquitoes (Anopheles farauti). The lack of flat zones owing to geomorphological formation contributed to the lowest parasite rate in the extremely small island. However, human-modified environments such as a wet-land (naturally formed but artificially reformed) and an open well played significant roles in other inter-village differences. The present findings imply significant roles of microenvironment in diversified malaria prevalence and suggest some ways of mitigation of malarial hazards.

Marketing medical devices in Japan.

The control of medical devices in Japan has recently undergone significant changes as the country brings its systems into line with those of the United States and Europe. This article discusses pre-market approval, quality system requirements and post-market surveillance. Many technical issues have been harmonized but language is likely to continue to be a barrier to trade. Details of information services that are available to foreign manufacturers and importers are supplied.

Significant association between TIM1 promoter polymorphisms and protection against cerebral malaria in Thailand.

Although cerebral malaria is a major life-threatening complication of Plasmodium falciparum infection, its pathophysiology is not well understood. Prolonged activation of the T helper type 1 (Th1) response characterized by the production of pro-inflammatory cytokines such as IFN-gamma and TNF-alpha has been suggested to be responsible for immunopathological process leading to cerebral malaria unless they are downregulated by the anti-inflamatory cytokines produced by the Th2 response. The T cell immunoglobulin and mucin domain (TIM) family of proteins are cell surface proteins involved in regulating Th1 and Th2 immune responses. In this study, the possible association between the polymorphisms of TIM1, TIM3, and TIMD4 genes and the severity of malaria was examined in 478 adult Thai patients infected with P. falciparum malaria. The TIM1 promoter haplotype comprising three derived alleles, -1637A (rs7702919), -1549C (rs41297577) and -1454A (rs41297579), which were in complete linkage disequilibrium, was significantly associated with protection against cerebral malaria (OR = 0.41; 95% CI = 0.24-0.71; P= 0.0009). Allele-specific transcription quantification analysis revealed that the level of mRNA transcribed from TIM1 was higher for the protective promoter haplotype than for the other promoter haplotype (P= 0.004). Engagement with TIM1 in combination with T cell receptor stimulation induces anti-inflammatory Th2 cytokine production, which can protect the development of cerebral malaria caused by overproduction of pro-inflammatory Th1 cytokines. The present results suggest that the higher TIM1 expression associated with the protective TIM1 promoter haplotype confers protection against cerebral malaria.