Emergence of influenza B viruses with reduced sensitivity to neuraminidase inhibitors

Context  Very little is known about the frequency of generation and transmissibility of influenza B viruses with reduced sensitivity to neuraminidase inhibitors. Furthermore, transmission of resistant virus, whether influenza A or B, has not been recognized to date. Objective  To assess the prevalence and transmissibility of influenza B viruses with reduced sensitivity to neuraminidase inhibitors. Design, Setting, and Patients  Investigation of the neuraminidase inhibitor sensitivity of influenza B isolates from 74 children before and after oseltamivir therapy and from 348 untreated patients with influenza (including 66 adults) seen at 4 community hospitals in Japan during the 2004-2005 influenza season. Four hundred twenty-two viruses from untreated patients and 74 samples from patients after oseltamivir therapy were analyzed. Main Outcome Measure  Sialidase inhibition assay was used to test the drug sensitivities of influenza B viruses. The neuraminidase and hemagglutinin genes of viruses showing reduced sensitivity to neuraminidase inhibitors were sequenced to identify mutations that have the potential to confer reduced sensitivity to these drugs. Results  In 1 (1.4%) of the 74 children who had received oseltamivir, we identified a variant with reduced drug sensitivity possessing a Gly402Ser neuraminidase substitution. We also identified variants with reduced sensitivity carrying an Asp198Asn, Ile222Thr, or Ser250Gly mutation in 7 (1.7%) of the 422 viruses from untreated patients. Review of the clinical and viral genetic information available on these 7 patients indicated that 4 were likely infected in a community setting, while the remaining 3 were probably infected through contact with siblings shedding the mutant viruses. Conclusions  In this population, influenza B viruses with reduced sensitivity to neuraminidase inhibitors do not arise as frequently as resistant influenza A viruses. However, they appear to be transmitted within communities and families, requiring continued close monitoring.      

The presence of midkine and its possible implication in human ovarian follicles

PROBLEM: Ovarian follicles undergo a dynamic change to provide a mature ovum, and the process involves angiogenesis, follicular cell proliferation and leukocyte recruitment. Midkine (MK) is a heparin-binding growth factor that has angiogenic, mitogenic, and chemotactic activities. In the present study, we investigated the presence of MK and its possible role in human ovarian follicles. METHOD OF STUDY: Follicular fluid (FF) and luteinized granulosa cells (LGC) were collected from women undergoing in vitro fertilization and embryo transfer. Expression of MK protein in FF was examined by Western blotting. Concentrations of MK, estradiol and oxygen in FF were measured. 5-bromo-2'-deoxyuridine (BrdU) incorporation assay was performed in LGC. Normal ovarian tissues were obtained surgically and used in in-situ hybridization of MK mRNA. RESULTS: The presence of MK protein was verified in FF. MK mRNA was expressed in both granulosa cells and theca cells of large follicles. There is a significant negative correlation between the concentrations of MK and oxygen in FF, and a significant positive correlation between the concentrations of MK and estradiol. MK promoted BrdU uptake in LGC. CONCLUSION: The present findings imply that hypoxic condition, a characteristic of growing follicles, associates with the production of MK. Given that MK is involved in granulosa cell proliferation and estradiol production in developing follicles, MK may play a role as a local regulator in the human ovary.     

Mutational analysis of CACNA1G in idiopathic generalized epilepsy. Mutation in brief #962. Online

Recent studies have strongly implicated low voltage-activated/T-type calcium channels (T-channels) in the etiology of epilepsy. Here, we report the results of a mutational analysis of the CACNA1G gene, encoding the T-channel Ca(V)3.1/(1G) subunit, using a cohort of 123 mostly Japanese and Hispanic patients with idiopathic generalized epilepsies (IGE) and 360 healthy control individuals. We found 13 variants, including five which involved amino acid substitutions. One variant, c.1709C>T (Ala570Val), is present in a sporadic case of juvenile myoclonic epilepsy (JME) with early childhood absence and astatic seizures, but was not found in control samples. Another variant, c.3265G>T (Ala1089Ser), was observed in three family members affected with JME, and also in one control individual. Two JME patients and three control individuals harbored a third variant, c.2968G>A (Asp980Asn). Although not statistically significant, slightly faster inactivation decay rates were observed in some mutant channels. Our collective findings flag CACNA1G as a potential susceptibility locus for IGE subsyndromes that warrants closer investigation.     

Human leukocyte antigen matching estimations in a hypothetical bank of human embryonic stem cell lines in the Japanese population for use in cell transplantation therapy

Human embryonic stem (hES) cell lines are of great potential in cell transplantation therapy. However, recipients of such allogeneic transplants probably need treatment with immunosuppressants. Recently, Taylor et al. [Lancet 2005;366:2019-2025] proposed banking of hES cell lines and estimated the required number of hES cell lines for beneficial human leukocyte antigen (HLA) matching in the U.K. population. Here, we carried out such an estimation in the Japanese population. We calculated the proportion of patients who can find at least one HLA-matched donor at three loci of HLA-A, -B, and -DR. With a bank of hES cell lines from 170 randomly selected donated embryos, 80% of patients were expected to find at least one hES cell line with a single mismatch at one HLA locus or a better match. Furthermore, 80% of patients are expected to find at least one donor with complete matching at the three HLA loci if parthenogenetic homozygous hES cell lines are established from 55 randomly selected donated oocytes. The relatively low ethnic diversity of the Japanese population may have resulted in a high success rate in beneficial matching. Moreover, parthenogenetic hES cell lines can greatly reduce the number required for a higher degree of HLA matching.     

Short-term culture and gammaH2AX flow cytometry determine differences in individual radiosensitivity in human peripheral T lymphocytes

Histone H2AX, a subfamily of histone H2A, is phosphorylated and forms proteinaceous repair foci at the sites of DNA double-strand breaks in response to genotoxic insults, such as ionizing radiation. This process is believed to play a key role in the repair of DNA damage. In this study, we established a flow cytometry (FCM) system for measuring radiation-induced phosphorylated histone H2AX (gammaH2AX) in cultured human T lymphocytes to evaluate individual radiation sensitivity in vitro. Irradiation of short-term ( approximately 7 days) cultured T lymphocytes exhibited significant interindividual, but not interexperimental, differences in the cellular content of gammaH2AX 6 hr after 4 Gy of X-irradiation in three independent experiments using peripheral blood lymphocytes from six healthy donors. However, these differences were not as marked in uncultured lymphocytes, or lymphocytes that were cultured for a prolonged period ( approximately 13 days). The variation of gammaH2AX focus formation in lymphocytes of individuals was reproducible, with differences reaching about 1.5-fold following 7 days of culture. Therefore, the FCM-based gammaH2AX measurement appeared to reflect both the temporal course and the amount of DNA damage within the irradiated lymphocytes. Further, we confirmed that the differences in residual lymphocyte subsets were not involved in individual radiosensitivity. These results suggest that the FCM-based gammaH2AX assay using cultured T lymphocytes might be useful for the rapid and reliable assessment of individual radiation sensitivity involved in DNA damage repair.     

Transplantation of embryonic stem cell-derived endodermal cells into mice with induced lethal liver damage

ESCs are a potential cell source for cell therapy. However, there is no evidence that cell transplantation using ESC-derived hepatocytes is therapeutically effective. The main objective of this study was to assess the therapeutic efficacy of the transplantation of ESC-derived endodermal cells into a liver injury model. The beta-galactosidase-labeled mouse ESCs were differentiated into alpha-fetoprotein (AFP)-producing endodermal cells. AFP-producing cells or ESCs were transplanted into transgenic mice that expressed diphtheria toxin (DT) receptors under the control of an albumin enhancer/promoter. Selective damage was induced in the recipient hepatocytes by the administration of DT. Although the transplanted AFP-producing cells had repopulated only 3.4% of the total liver mass 7 days after cell transplantation, they replaced 32.8% of the liver by day 35. However, these engrafted cells decreased (18.3% at day 40 and 7.9% at day 50) after the cessation of DT administration, and few donor cells were observed by days 60-90. The survival rate of the AFP-producing cell-transplanted group (66.7%) was significantly higher in comparison with that of the sham-operated group (17.6%). No tumors were detected by day 50 in the AFP-producing cell-transplanted group; however, splenic teratomas did form 60 days or more after transplantation. ESC transplantation had no effect on survival rates; furthermore, there was a high frequency of tumors in the ESC-transplanted group 35 days after transplantation. In conclusion, this study demonstrates, for the first time, that ESC-derived endodermal cells improve the survival rates after transplantation into mice with induced hepatocellular injury. Disclosure of potential conflicts of interest is found at the end of this article.     

A syndactyly type IV locus maps to 7q36

Syndactyly occurs as an isolated abnormality or a part of a malformation syndrome. Syndactyly types I, II, III and V have been mapped to chromosomal regions 2q34–q36, 2q31–q32, 6q21–q23.2 and 2q31–q32, respectively, whereas syndactyly type IV (SD4) is extremely rare, and its gene localization has not yet been assigned. The SD4 manifests complete syndactyly of all fingers accompanied with polydactyly, and flexion of the fingers gives the hand a cup-shaped appearance. We performed a linkage and haplotype analysis of a Chinese pedigree with autosomal dominant, non-syndromic SD4 using a set of 406 microsatellite markers. The analysis gave the maximum two-point LOD score of 1.613 at recombination fraction of 0.00 and penetrance of 1.00. Thus, the SD4 locus in the family was likely assigned to a 17.39-cM region at a segment between markers D7S3070 and D7S559 at 7q36, although the LOD score obtained was not high enough to conclude the localization. Analysis of three candidate genes, LMBR1, SHH and ZRS, failed to identify any pathogenic mutations. Our gene mapping may give a clue to identify the putative SD4 gene and provide a better understanding of normal human limb development. Daisuke Sato and Desheng Liang equally contributed to this study.     

Gap junction coding genes and schizophrenia: a genetic association study

The aim of this study was to evaluate the association of genes that encode gap junction forming proteins and schizophrenia. Representative genetic candidates (Panx2 and Cx36) from two families of gap junction genes were selected for analysis. According to the present findings these genes represent both functional and positional candidates for schizophrenia. The sample was comprised of 381 schizophrenic patients, and the same number of matched controls was tested in this study in order to evaluate the possible influence of the aforementioned genes on the pathogenesis of schizophrenia. Four SNPs in the case of Panx2 and two SNPs in the case of Cx36 were selected for analysis. Allele-, genotype- and haplotype-wise association did not yield statistically significant results. These data do not suggest that Panx2 or Cx36 could increase the risk of schizophrenia in the Japanese population.     

Action profiles of statins and calcineurin inhibitors during human mixed lymphocyte reaction

The cell-to-cell interaction through binding intercellular adhesion molecule (ICAM)-1 and CD40 on monocytes and their ligands such as lymphocyte function-associated antigen (LFA)-1 and CD40 ligand (CD40L) on T-cells plays roles in cytokine production and T-cell proliferation. Interleukin (IL)-18, which is elevated in the plasma during acute rejection after organ transplantation, induces the expression of ICAM-1 and CD40 on monocytes, the production of interferon (IFN)-gamma and IL-12 and the proliferation of T-cells during the human mixed lymphocyte reaction (MLR). In addition to the cholesterol lowering effect, statins improve patient survival and decrease rejection episodes in transplant recipients. In the present study, we investigated the difference of effect of statins and calcineurin inhibitors during MLR. 3-Hydroxy-3-methylglutaryl coenzyme-A (HMG-CoA) reductase inhibitors, fluvastatin and pravastatin and statin-derived LFA-1 inhibitors, LFA703 and LFA878, which did not inhibit HMG-CoA reductase, suppressed the production of IFN-gamma and IL-12 and the lymphocyte proliferation as well as the expression of ICAM-1 and CD40 on monocytes regardless of the presence of IL-18. However, the calcineurin inhibitors, tacrolimus and cyclosporine A (CsA), inhibited the IL-18-enhanced cytokine production and lymphocyte proliferation without any effect on the adhesion molecule expression. Thus, the action mechanism of stain is different from that of calcineurin inhibitors.     

Congenital arhinia: molecular-genetic analysis of five patients

Congenital arhinia, complete absence of the nose, is an extremely rare anomaly with unknown cause. To our knowledge, a total of 36 cases have been reported, but there has been no molecular-genetic study on this anomaly. We encountered a sporadic case of congenital arhinia associated with a de novo chromosomal translocation, t(3;12)(q13.2;p11.2). This led us to analyze the patient by BAC-based FISH for translocation breakpoints and whole-genome array CGH for other possible deletions/duplications in the genome. We found in this patient an approximately 19 Mb deletion spanning from 3q11.2 to 3q13.31 but no disruption of any gene(s) at the other breakpoint, 12p11.2. As the deleted segment at 3q was a strong candidate region containing the putative arhinia gene, we also performed the array CGH in four other arhinia patients with normal karyotypes, as well as mutation analysis of two genes, COL8A1 and CPOX, selected among hundreds of genes located to the deleted region, because they are expressed during early stages of human craniofacial development. However, in the four patients, there were no copy number aberrations in the region examined or no mutations in the two genes. Although our study failed to identify the putative arhinia gene, the data may become a clue to unravel the underlying mechanism of arhinia.