Classifying genotype F of hepatitis B virus into F1 and F2 subtypes

AIM: To explore the propriety of providing hepatitis B virus (HBV) genotypes F and H with two distinct genotypes. METHODS: Eleven HBV isolates of genotype F (HBV/F) were recovered from patients living in San Francisco, Japan, Panama, and Venezuela, and their full-length sequences were determined. Phylogenetic analysis was carried out among them along with HBV isolates previously reported. RESULTS: Seven of them clustered with reported HBV/F isolates in the phylogenetic tree constructed on the entire genomic sequence. The remaining four flocked on another branch along with three HBV isolates formerly reported as genotype H. These seven HBV isolates, including the four in this study and the three reported, had a sequence divergence of 7.3-9.5% from the other HBV/F isolates, and differed by > 13.7% from HBV isolates of the other six genotypes (A-E and G). Based on a marked genomic divergence, falling just short of > 8% separating the seven genotypes, these seven HBV/F isolates were classified into F2 subtype and the former seven into F1 subtype provisionally. In a pairwise comparison of the S-gene sequences among the 7 HBV/F2 isolates and against 47 HBV/F1 isolates as well as 136 representing the other six genotypes (A-E and G), two clusters separated by distinct genetic distances emerged. CONCLUSION: Based on these analyses, classifying HBV/F isolates into two subtypes (F1 and F2) would be more appropriate than providing them with two distinct genotypes (F and H).     

alpha4-Integrin(+) endothelium derived from primate embryonic stem cells generates primitive and definitive hematopoietic cells

The mechanism of commencement of hematopoiesis in blood islands of the yolk sac and the aorta-gonad-mesonephros (AGM) region during primate embryogenesis remains elusive. In this study, we demonstrated that VE-cadherin(+)CD45(-) endothelial cells derived from nonhuman primate embryonic stem cells are able to generate primitive and definitive hematopoietic cells sequentially, as revealed by immunostaining of floating erythrocytes and colony-forming assay in cultures. Single bipotential progenitors for hematopoietic and endothelial lineages are included in this endothelial cell population. Furthermore, hemogenic activity of these endothelial cells is observed exclusively in the alpha4-integrin(+) subpopulation; bipotential progenitors are 4-fold enriched in this subpopulation. The kinetics of this hemogenic subpopulation is similar to that of hemogenic endothelial cells previously reported in the yolk sac and the AGM region in vivo in that they emerge for only a limited time. We suggest that VE-cadherin(+)CD45(-)alpha4-integrin(+) endothelial cells are involved in primitive and definitive hematopoiesis during primate embryogenesis, though VE-cadherin(-)CD45(-)alpha4-integrin(+) cells are the primary sources for primitive hematopoiesis.     

Reprogramming of primordial germ cells begins before migration into the genital ridge, making these cells inadequate donors for reproductive cloning

Germ cells undergo epigenetic modifications as they develop, which suggests that they may be ideal donors for nuclear transfer (cloning). In this study, nuclei from confirmed embryonic germ cells were used as donors to determine whether they are competent for cloning and at which stage they are most competent. Embryos cloned from migrating 10.5-days-postcoitum (dpc) primordial germ cells (PGCs) showed normal morphological development to midgestation but died shortly thereafter. In contrast, embryos cloned from later-stage germ cells were developmentally delayed at midgestation. Thus, donor germ cell age inversely correlated with the developmental stage attained by cloned embryos. The methylation status of the H19- and Snrpn-imprinting control regions in germ cell clones paralleled that of the donors, and revealed that demethylation, or erasure of imprints, was already initiated in PGCs at 10.5 dpc and was complete by 13.5 dpc. Similarly, clones derived from male 15.5-dpc germ cells showed increased methylation correlating with the initiation of de novo methylation that resets imprints at this stage, and clones from neonatal germ cells showed nearly complete methylation in the H19 imprinting control region. These results indicate that the epigenetic state of the donor nucleus is retained in cloned embryos, and that germ cells are therefore inadequate nuclear donors for cloning because they are either erasing or resetting epigenetic patterns.     

Epidemiologic and virologic characteristics of hepatitis B virus genotype B having the recombination with genotype C

BACKGROUND & AIMS: Hepatitis B virus (HBV) isolates of genotype B (HBV/B) with or without the recombination with genotype C over the precore region plus core gene have been reported. METHODS: All the 41 HBV/B isolates having the recombination with genotype C (HBV/Ba) possessed the nucleotide 1838 of A in contrast to that of G in all 29 of those without the recombination (HBV/Bj). Taking advantage of this single nucleotide polymorphism, a restriction fragment length polymorphism method was developed that distinguished HBV/Ba from HBV/Bj. RESULTS: HBV/Bj was detected in 90 of the 97 (93%) carriers of HBV/B from Japan, whereas HBV/Ba occurred in all 177 carriers of HBV/B from other countries (China, 20; Hong Kong, 45; Taiwan, 32; Thailand, 30; Vietnam, 30; and the United States, 20 [all of an Asian ethnicity]). In a case-control study, hepatitis B e antigen (HBeAg) and the double mutation in the core promoter (T1762/A1764) were significantly more frequent in 80 carriers each of HBV/Ba than HBV/Bj (35% vs. 18%, P < 0.05 and 33% vs. 15%, P < 0.05, respectively). Differences in the prevalence of HBeAg were more conspicuous between the carriers of HBV/Bj and HBV/Ba older than 30 years (5 of 66 or 8% vs. 16 of 62 or 26%, P < 0.01). CONCLUSIONS: HBV/B having the recombination with genotype C is frequent in Asia, except in Japan, and HBeAg is more prevalent in carriers of HBV/Ba than HBV/Bj.     

Strict glycemic control ameliorates the increase of carotid IMT in patients with type 2 diabetes

The aim of this study was to investigate the effect of strict glycemic control on the carotid artery intima-media thickness (IMT) in type 2 diabetic patients who initially had good glycemic control (HbA1c between 5.8 and 6.4 %). The subjects were 67 patients showing deterioration of the mean HbA1c over 3 years by more than 0.2% from baseline (D group) and 33 subjects showing improvement of the mean HbA1c by more than 0.2% from baseline (A group). The clinical characteristics and annual change of IMT during the observation period were compared between the two groups in a 3-year retrospective longitudinal study. The baseline characteristics and the mean values of BMI, blood pressure, and serum lipids during the study period did not differ significantly between the two groups. However, the mean HbA1c of A group was significantly lower than that of D group (5.67 +/- 0.10 vs. 6.28 +/- 0.08, mean +/- SE, p<0.001). The adjusted annual increase rate of IMT was significantly less in A group than in D group (-0.035 +/- 0.019 vs. 0.036 +/- 0.015 mm, M +/- SEM, p<0.001). These results indicate that further improvement of glycemic control from a good HbA1c value can prevent an increase of IMT in type 2 diabetic patients.     

Assignment of gene coding human T-cell differentiation antigen,Tpl20, to chromosome 11

A pan T-cell antigen with a molecular weight of 120 kilodaltons (kd) is recognized by a monoclonal antibody, Tp120, produced in our laboratories. Two hybrid clones reactive with this Tp120 antibody were established from the fusion between concanavalin A-stimulated human peripheral blood lymphocytes and hypoxanthine-guanine phosphoribosyltransferase-deficient mouse T cell leukemia, BW5147. These two clones were also positive with two other antibodies, 12.1 and T12, both of which detect 120kd pan T-cell antigen. Karyotype analysis showed that one clone retained human chromosomes 6, 7pq^–, and 11, and the other maintained chromosomes 11 and 21. As soon as both of these clones lost the chromosome 11, the expression of Tp120 became negative. The presence of human chromosome 11 was confirmed by the isozyme analysis of lactate dehydrogenase-A. The results indicated that the presence of chromosome 11 was essential for expression of 120kd pan T-cell antigen.     

Phase I Trial of FLAGM with High Doses of Cytosine Arabinoside for Relapsed, Refractory Acute Myeloid Leukemia: Study of the Japan Adult Leukemia Study Group (JALSG)

This study was designed to determine the optimal high dose for cytosine arabinoside (ara-C) in combination with fludarabine, granulocyte colony-stimulating factor, and mitoxantrone (FLAGM) in adult patients with relapsed or refractory acute myeloid leukemia. Nine patients were enrolled at increasing dosage levels of ara-C (8, 12, and 16 g/m2 per dose level). Ara-C and fludarabine were administered once a day at level 1, once or twice a day at level 2, and twice a day at level 3. All patients had grade 4 hematologic toxicity. The most common adverse events were of grade 2 or less, with nausea and vomiting being the most common (6 events), followed by diarrhea (5 events), and rash (5 events). Of the 13 grade 3 nonhematologic toxicities reported, the 2 most common were febrile neutropenia (6 events) and disseminated intravascular coagulation (3 events). No early deaths were observed. FLAGM with high-dose ara-C was considered safe for patients, and the recommended dosage of ara-C in this study was 2 g/m2 every 12 hours for a total dose of 16 g/m2.     

急性白血病细胞SHIP基因的突变分析

目的　评价SHIP基因突变在白血病发病中的作用。方法　利用逆转录 聚合酶链反应(RT PCR)、单链构象多态性 (SSCP)及DNA序列分析技术检测了 4 1例急性白血病患者、5 0名正常人的骨髓或外周血标本、8株白血病细胞系SHIP基因表达及突变情况。结果　RT PCR显示所有标本中都有SHIP基因表达 ,发现 32例急性髓系白血病 (AML)患者中有 7例 (2 2 % )和 9例急性淋巴细胞白血病 (ALL)患者中有 1例 (12 % )存在SHIP基因的突变 ,其中 1例AML患者发病时标本同时存在 2个错义突变 ,而完全缓解后消失。发病时患者的白血病细胞在体外随着IL 3的刺激其Akt磷酸化明显增加。结论　首次发现急性白血病细胞中SHIP基因突变 ,提示SHIP基因的突变可能与白血病发病有关 ,在造血细胞中 ,很可能作为一个抑癌基因通过负性调节PI3K/Akt信号通路发挥作用     

Characteristics of Japanese subjects who progress from normal to impaired glucose tolerance. Longitudinal study excluding changes in body weight

In this retrospective longitudinal study, we focused on the clinical characteristics of Japanese individuals with recent onset impaired glucose tolerance (IGT) who have been followed up for insulin secretory function and 75-gram oral glucose tolerance test (OGTT) for more than 3 years annually before they progressed from normal glucose tolerance (NGT) to IGT. Subjects whose body weight did not show significant change for the period were selected and labeled as either NGT (no change in OGTT over 3 years) or IGT (progressors from NGT to IGT) groups (n = 24, each). We compared the basal biochemical data and response of plasma glucose and serum insulin after OGTT of the two groups. In the IGT progressors, significant increase of plasma glucose at 30 to 120 minutes during OGTT and significant decrease of HDL-cholesterol were observed since 3 years before onset of IGT. In addition to increase of serum glucose and decrease of HDL-cholesterol, serum insulin at 120 minutes during OGTT were significantly and remarkably high at onset and 3 years before onset of IGT. Plasma glucose at 30-120 minutes and serum insulin level at 120 minutes after glucose load are potentially significant predictors of progression from NGT to IGT even in subjects who do not show increase of body weight.