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The csrRS two-component regulatory system is an important element in the pathogenesis of group A Streptococcus (GAS). The main goal of this study is to understand the association between csrRS polymorphisms and GAS infection. We sequenced the csrRS genes from 172 clinical isolates, including 81 invasive and 91 noninvasive isolates, and then employed phylogenetic analyses to determine the consequences of the csrRS polymorphisms. In total, 13 and 26 polymorphic loci were detected in the csrR and csrS genes, respectively. These polymorphisms constituted 14 csrR and 25 csrS alleles, producing two CsrR and seven CsrS variants, respectively. Three invasive isolates contained an indel in csrS, but no indel was identified in csrR. The frequency and distribution of polymorphisms in csrR and csrS was significantly different between the invasive and noninvasive infection isolates ( p < 0.001). For CsrR, only one noninvasive isolate was identified to have a V29I mutation. The amino acid substitutions in CsrS included S32P (0.6 %), E265G (0.6 %), E265K (0.6 %), I332V (1.7 %), and N498K (82.6 %). Isolates with an N498K single mutation were more likely to be associated with invasive infections ( p < 0.001). The dN/dS ratio indicated that both csrR and csrS were under purifying selection. The fixation index suggested a moderate evolutionary differentiation of the csrR and csrS alleles between invasive and noninvasive isolates. The identification of these genetic differences within the csrRS loci will provide a better understanding of the pathogenesis of GAS. [ABSTRACT FROM AUTHOR]

The genetic diversity and phylogenetic relationships of Sweet potato feathery mottle virus (SPFMV) and Sweet potato virus G (SPVG), two major sweet potato viruses in Sichuan, the largest sweet potato producing area of China, were analyzed. A total of 18 virus isolates, including 12 SPFMV isolates and six SPVG isolates, were obtained from different fields and characterized by RT-PCR and sequencing. Sequence alignments revealed 77.3%-99.8% and 85.4%-99.6% nucleotide identities for the coat protein gene of SPFMV and SPVG, respectively. Phylogenetic analysis divided SPFMV isolates into groups RC, O and C, and SPGV isolates into groups CH and CH2. The information presented in this study is useful for the development of engineered resistance to local virus strains in sweet potato. [ABSTRACT FROM AUTHOR]

Previously we reported significant associations of the human leukocyte antigen (HLA)-DPB1 05:01 with memory against hepatitis B (HB) vaccination. However, the effects of HLA-DPB1 on antibodies to hepatitis B surface antigen (anti-HBs) kinetics were not explored. We followed up a cohort of 1974 HB booster recipients and quantified their 1-month and 1-year post-booster anti-HBs titers. A total of 681 subjects were randomly selected and typed for HLA-DPB1. We found that male subjects, undetectable pre-booster titers, and 05:01 homozygotes led to significantly lower post-booster anti-HBs titers. The geometric means (95% confidence interval (CI)) of 1-month post-booster anti-HBs titers were 4.68 (2.69-8.12), 23.01 (14.96-35.40) and 50.06 (27.20-92.13) mIU ml−1 for subjects carrying two, one and no HLA-DPB1 05:01 allele. The corresponding figures for 1-year post-booster anti-HBs titers were 1.26 (0.73-2.18), 4.72 (3.08-7.25) and 7.32 (3.75-13.56) mIU ml−1. There were significant associations of post-booster anti-HBs titers with the number of HLA-DPB1 risk and protective alleles. Among booster responders, anti-HBs decay rates were significantly reduced in subjects who had detectable pre-booster anti-HBs titers and the HLA-DPB1 05:01 allele. Our results indicated that HLA-DPB1 influences the kinetics of anti-HBs. The long-term memory against hepatitis B surface antigen (HBsAg) and the residual serum titers of anti-HBs after HB vaccination may be influenced by different mechanisms as evidenced by their inverse trend of associations with the 05:01 allele. [ABSTRACT FROM AUTHOR]

Dehydrins are a group of plant proteins that usually accumulate in response to environmental stresses. They are proposed to play specific protective roles in plant cells. Present study showed that the accumulation of dehydrins in water-stressed barley ( Hordeum vulgare L.) seedlings was influenced by their treatment with salicylic acid (SA). The level of dehydrin proteins was increased by 0.20 mM SA, but decreased by 0.50 mM SA treatment. Both mRNA expression and protein accumulation of a typical barley dehydrin, DHN5, were enhanced by SA treatment when SA concentrations were lower than 0.25 mM. However, the higher SA concentrations significantly decreased the protein level of DHN5 despite of a stable mRNA level. Our results also showed that low SA concentrations (less than 0.25 mM) decreased the electrolyte leakage and malondialdehyde (MDA) and H2O2 contents in water-stressed barley seedlings. But high SA concentrations (more than 0.25 mM) enhanced H2O2 accumulation, tended to cause more electrolyte leakage, and increase MDA content. These data indicated that SA could up-regulate the dehydrin gene expression and protein accumulation. Since the protective role of dehydrins in plant cells, such effect could be an important reason for the SA-mediated alleviation on water stress injury. But excessive SA could suppress the accumulation of dehydrin proteins and aggravate the oxidative damage. [ABSTRACT FROM AUTHOR]

Individuals with end-stage renal disease (ESRD) are 10- to 25-fold more likely than immunocompetent people to develop active tuberculosis (TB) and are candidates for being treated for latent TB infection (LTBI). However, diagnosis using the tuberculin skin test (TST) is doubly difficult due to cutaneous anergy and cross-reactions with Bacille–Calmette–Guérin (BCG) vaccination. This was a prospective, doublematched, cohort study in which 32 ESRD patients and 32 age-matched, healthy controls were enrolled. The TST and two new interferon-γ blood tests, QuantiFERON-TB Gold (QFT-G) and T-SPOT.TB (ELISPOT), were performed. The subjects were followed up 2 years for active TB disease. ELISPOT was done in ESRD patients only. Compared to the healthy controls, a high prevalence of LTBI was found in the ESRD patients by TST (62.5%, 95% confidence interval [CI] 43.7–78.9), QFT-G (40.0%, 95% CI 22.7–59.4), and ELISPOT (46.9%, 95% CI 29.1–65.3). Agreement was moderate (kappa [κ] = 0.53) for QFT-G and ELISPOT but only slight between TST and QFT-G (κ = 0.25) and fair between TST and ELISPOT (κ = 0.32). ESRD (p = 0.03) and diabetes mellitus (p = 0.04) were significant risk factors for QFT-G positivity on the multivariable analysis. The overall rate of active TB was 1.66 cases per 100 person-years (pys), with the rate higher in patients with ESRD (3.53 per 100 pys) and those with positive (3.40 per 100 pys) and indeterminate QFT results (30.16 per 100 pys), although the difference was not statistically significant. Sensitivity, specificity, and positive and negative predictive values of QFT-G for active TB was 100%, 62.1%, 8.3% and 100%. This pilot study is the first to compare QFT-G, ELISPOT, and TST in ESRD patients on hemodialysis and demonstrates a high prevalence of LTBI in this population. In our study, the QFT-G was the more accurate method for identifying those truly infected with Mycobacterium tuberculosis, even in BCG-vaccinated individuals. [ABSTRACT FROM AUTHOR]

Melioidosis is a disease prevalent in the tropics, especially in Southeast Asia. The most common clinical presentations are bacteremic pneumonia and abscess formation in various organs. Although a wide variety of disease presentations are reported for melioidosis, acute cholangitis has not been previously reported. Herein, we report a 54-year-old woman who had fever, right upper abdominal pain and jaundice 1 week after a flood caused by a typhoon in southern Taiwan. Acute cholangitis and pneumonia with septic shock caused by Burkholderia pseudomallei were subsequently diagnosed. [ABSTRACT FROM AUTHOR]

The INK4A locus encodes two tumor suppressor genes, p16INK4A and p14ARF, transcribed using alternative exons 1α or 1β spliced onto the same exons 2 and 3. Both p16INK4A and p14ARF are capable of inhibiting the cell-cycle progression, albeit in different manner; p16INK4A is phosphorylation of retinoblastoma (pRB) dependent while p14ARF is p53-dependent. In this study, we report the discovery of a novel variant of p16INK4A, termed p16γ, in a primary T-cell acute lymphoblastic leukemia (T-ALL) patient sample and a neuroblastoma cell line, which was expressed at both the transcriptional and translational levels. Cloning and sequencing of the p16γ cDNA revealed that p16γ was identical to p16INK4A, except that it contained an in-frame insertion of 197 bp between exons 2 and 3. p16γ expression was detected in the majority of p16INK4A-expressing primary T-ALL and B-ALL patient samples and other p16INK4A-expressing tumor samples, but was only barely detectable in some normal mononuclear cells and other non-tumor samples. Structural analysis by nuclear magnetic resonance and circular dichroism confirmed that p16γ, like p16INK4A, is also an ankyrin-repeat protein. Functional analysis of p16γ revealed that p16γ protein interacted with cyclin D-dependent kinase4 and inhibited its kinase activity. Using a luciferase reporter assay, the transfection of p16γ repressed the E2F response, the downstream target of pRB, with an efficacy equivalent to that of p16INK4A. Moreover p16γ, like p16INK4A, induced cell-cycle arrest at G0/G1, and inhibited cell growth in colony formation assay.Oncogene (2007) 26, 7017–7027; doi:10.1038/sj.onc.1210507; published online 7 May 2007 [ABSTRACT FROM AUTHOR]

Background: Fever of unknown origin (FUO) is a challenging problem worldwide. There was no prospective study of FUO in the past two decades in Taiwan. A prospective study was conducted. Materials and Methods: The prospective study was undertaken from March 2001 to May 2002. All patients fulfilling the modified criteria for FUO, either admitted, referred or consulted in a medical center in southern Taiwan, were enrolled for analysis. Results: A total of 94 cases met the criteria of FUO. The final diagnoses of FUO consisted of 54 infectious diseases (57.4%), 8 hematologic/neoplastic (8.5%), 7 noninfectious inflammatory (7.4%), 8 miscellaneous (8.5%) and 17 undiagnosed (18.1%) cases. The single most common cause of FUO was tuberculosis. Some infectious diseases, such as rickettsiosis and melioidosis, were rarely reported in western countries. Three patients with hemophagocytotic syndrome without ascertainable etiologies were present with FUO in this study. Between the patients with and those without a final diagnosis, the short-term survival (3 months) was compared by the Kaplan-Meier analysis, which revealed no difference. Conclusions: Mycobacteriosis is still the leading cause of FUO in Taiwan and it is important to identify this treatable disease from all causes of FUO. This study has showed geographical variation among the studies of FUO. [ABSTRACT FROM AUTHOR]

In(Ga)As/GaAs quantum-dot (QD) lasers with emission wavelength at 1295 nm at room temperature are fabricated. The laser active region contains a threefold stack of QD layers with surface dot density of 4.56 × 1010 cm-2. The laser structure is aluminum-free with InGaP as cladding layers. Threshold current density of a narrow stripe laser of 8 µm wide and 3.5 mm long is 152.5 A/cm2. The highest relaxation oscillation frequency measured at room temperature is 1.8 GHz, corresponding to a modulation bandwidth of 2.8 GHz due to the small damping factor. From the above measurement, the differential gain and gain compression factor were extracted to be 4.3 × 10-16 cm2 and 3.4 × 10-17 cm3, respectively. Using these parameters, the maximum modulation bandwidthf3 dB max is estimated as 7.9 GHz. [ABSTRACT FROM AUTHOR]

A 69-year-old man with Sweet's syndrome and myelodysplastic syndrome presented with pneumonia and respiratory distress. He had been taking corticosteroids and methotrexate. The diagnosis of Legionnaires' disease was established by the isolation of Legionella pneumophila serogroup 6 from sputum and a fourfold seroconversion of Legionella antibodies to 1:512. Legionella pneumophila serogroup 6 was isolated from faucets in two homes owned by the patient. Strains of Legionella pneumophila serogroup 6 isolated from the patient's sputum and from one home were demonstrated to be genetically identical by pulsed-field gel electrophoresis but different from strains found in the other home and in a hospital outpatient clinic that he visited. This case illustrates an emerging public health issue concerning acquisition of community-acquired Legionnaires' disease from the homes of immunocompromised hosts. This is the first such case reported in Asia. [ABSTRACT FROM AUTHOR]

Background: Taiwan is endemic for viral hepatitis infections. A field survey was performed in the isolated aborigines in Hualien, eastern Taiwan, to investigate the geographic and ethnic variations in hepatitis epidemiology. Materials and Methods: From 1996 to 1998, blood was drawn from 1,748 subjects from two southern Ami and two northern Atayal villages for serum markers of hepatitis A, B and C. Results: Hepatitis A infection approached 100% in all groups. Hepatitis B infection and carrier rates were higher in the Atayal than in the Ami (92.3% vs 49.1% and 20.8% vs 5.3%; p < 0.01). Hepatitis C infection rates were higher in three villages (27.5%, 20.1% and 25.4% vs 3.6%; p < 0.01). Hepatitis C infection in creased with age (p < 0.01) while hepatitis B infection did not. Conclusion: Hepatitis A infected most aborigines before the age of 15 years. Hepatitis B seldom infected people after the age of 15 years, while hepatitis C continued to infect people who were older. Geographic factors are important for hepatitis C infection, whereas for hepatitis B infection, in addition ethnicity is also important. [ABSTRACT FROM AUTHOR]