Rate of red blood cell destruction varies in different strains of mice infected with Plasmodium berghei-ANKA after chronic exposure

<p>Abstract</p> <p>Background</p> <p>Severe malaria anaemia in the semi-immune individuals in the holo-endemic area has been observed to occur at low parasite density with individual variation in the responses. Thus the following has been thought to be involved: auto-immune-mediated mechanisms of uninfected red blood cell destruction, and host genetic factors to explain the differences in individual responses under the same malaria transmission. In this study, the extent of red blood cell (RBC) destruction in different strains of semi-immune mice model at relatively low parasitaemia was studied.</p> <p>Methodology</p> <p>To generate semi-immunity, four strains of mice were taken through several cycles of infection and treatment. By means of immunofluorescent assay and ELISA, sera were screened for anti-erythrocyte auto-antibodies, and their relationship with haematological parameters and parasitaemia in the strains of semi-immune mice was investigated.</p> <p>Results</p> <p>Upon challenge with <it>Plasmodium berghei </it>ANKA after generating semi-immune status, different mean percentage haemoglobin (Hb) drop was observed in the mice strains (Balb/c = 47.1%; NZW = 30.05%; C57BL/6 = 28.44%; CBA = 25.1%), which occurred on different days for each strain (for Balb/c, mean period = 13.6 days; for C57BL/6, NZW, and CBA mean period = 10.6, 10.8, 10.9 days respectively). Binding of antibody to white ghost RBCs was observed in sera of the four strains of semi-immune mice by immunofluorescence. Mean percentage Hb drop per parasitaemia was highest in Balb/c (73.6), followed by C57BL/6 (8.6), CBA (6.9) and NZW (4.0), p = 0.0005. Consequently, auto-antibodies level to ghost RBC were correlated with degree of anaemia and were highest in Balb/c, when compared with the other strains, p < 0.001.</p> <p>Conclusion</p> <p>The results presented in this study seem to indicate that anti-RBC auto-antibodies may be involved in the destruction of uninfected RBC in semi-immune mice at relatively low parasite burden. Host genetic factors may also influence the outcome of auto-immune mediated destruction of RBC due to the variation in Hb loss per % parasitaemia and differences in antibody titer for each semi-immune mice strain. However, further studies at the molecular level ought to be carried out to confirm this.</p

Partial mitochondrial DNA sequences suggest the existence of a cryptic species within the Leucosphyrus group of the genus Anopheles (Diptera: Culicidae), forest malaria vectors, in northern Vietnam

<p>Abstract</p> <p>Background</p> <p>During the last decade, Southeast Asian countries have been very successful in reducing the burden of malaria. However, malaria remains endemic in these countries, especially in remote and forested areas. The Leucosphyrus group of the genus <it>Anopheles </it>harbors the most important malaria vectors in forested areas of Southeast Asia. In Vietnam, previous molecular studies have resulted in the identification of only <it>Anopheles dirus sensu stricto </it>(previously known as <it>An. dirus </it>species A) among the Leucosphyrus group members. However, Vietnamese entomologists have recognized that mosquitoes belonging to the Leucosphyrus group in northern Vietnam exhibit morphological characteristics similar to those of <it>Anopheles takasagoensis</it>, which has been reported only from Taiwan. Here, we aimed to confirm the genetic and morphological identities of the members of the Leucosphyrus group in Vietnam.</p> <p>Results</p> <p>In the molecular phylogenetic trees reconstructed using partial <it>COI </it>and <it>ND6 </it>mitochondrial gene sequences, samples collected from southern and central Vietnam clustered together with GenBank sequences of <it>An. dirus </it>that were obtained from Thailand. However, samples from northern Vietnam formed a distinct clade separated from both <it>An. dirus </it>and <it>An. takasagoensis </it>by other valid species.</p> <p>Conclusions</p> <p>The results suggest the existence of a cryptic species in northern Vietnam that is morphologically similar to, but phylogenetically distant from both <it>An. dirus </it>and <it>An. takasagoensis</it>. We have tentatively designated this possible cryptic species as <it>Anopheles </it>aff. <it>takasagoensis </it>for convenience, until a valid name is assigned. However, it is difficult to distinguish the species solely on the basis of morphological characteristics. Further studies on such as karyotypes and polytene chromosome banding patterns are necessary to confirm whether <it>An</it>. aff. <it>takasagoensis </it>is a valid species. Moreover, studies on (1) the geographic distribution, which is potentially spreading along the Vietnam, China, Laos, and Myanmar borders; (2) morphological and ecological characteristics; and (3) vectorial capacity of this newly identified cryptic species of <it>An. dirus</it>, which is one of the most important malaria vectors in the mainland of Southeast Asia, are necessary for planning efficient malaria vector control programs in this region.</p

Truncated KCNQ1 mutant, A178fs/105, forms hetero-multimer channel with wild-type causing a dominant-negative suppression due to trafficking defect

AbstractWe identified a novel mutation Ala178fs/105 missing S3–S6 and C-terminus portions of KCNQ1 channel. Ala178fs/105-KCNQ1 expressed in COS-7 cells demonstrated no current expression. Co-expression with wild-type (WT) revealed a dominant-negative effect, which suggests the formation of hetero-multimer by mutant and WT. Confocal laser microscopy displayed intracellular retention of Ala178fs/105-KCNQ1 protein. Co-expression of the mutant and WT also increased intracellular retention of channel protein compared to WT alone. Our findings suggest a novel mechanism for LQT1 that the truncated S1–S2 KCNQ1 mutant forms hetero-multimer and cause a dominant-negative effect due to trafficking defect

Author Correction: Exposure to paternal tobacco smoking increased child hospitalization for lower respiratory infections but not for other diseases in Vietnam.

An amendment to this paper has been published and can be accessed via a link at the top of the paper

Elevated Levels of Cell-Free Circulating DNA in Patients with Acute Dengue Virus Infection

BACKGROUND: Apoptosis is thought to play a role in the pathogenesis of severe dengue and the release of cell-free DNA into the circulatory system in several medical conditions. Therefore, we investigated circulating DNA as a potential biomarker for severe dengue. METHODS AND FINDINGS: A direct fluorometric degradation assay using PicoGreen was performed to quantify cell-free DNA from patient plasma. Circulating DNA levels were significantly higher in patients with dengue virus infection than with other febrile illnesses and healthy controls. Remarkably, the increase of DNA levels correlated with the severity of dengue. Additionally, multivariate logistic regression analysis showed that circulating DNA levels independently correlated with dengue shock syndrome. CONCLUSIONS: Circulating DNA levels were increased in dengue patients and correlated with dengue severity. Additional studies are required to show the benefits of this biomarker in early dengue diagnosis and for the prognosis of shock complication

Tcap gene mutations in hypertrophic cardiomyopathy and dilated cardiomyopathy

ObjectivesWe sought to explore the relationship between a Tcap gene (TCAP)abnormality and cardiomyopathy.BackgroundHypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM) cause severe heart failure and sudden death. Recent genetic investigations have revealed that mutations of genes encoding Z-disc components, including titin and muscle LIM protein (MLP), are the primary cause of both HCM and DCM. The Z-disc plays a role in establishing the mechanical coupling of sarcomeric contraction and stretching, with the titin/Tcap/MLP complex serving as a mechanical stretch sensor. Tcap interacts with the calsarcin, which tethers the calcineurin to the Z-disc.MethodsThe TCAPwas analyzed in 346 patients with HCM (236 familial and 110 sporadic cases) and 136 patients with DCM (34 familial and 102 sporadic cases). Two different in vitro qualitative assays—yeast two-hybrid and glutathion S-transferase pull-down competition—were performed in order to investigate functional changes in Tcap's interaction with MLP, titin, and calsarcin-1 caused by the identified mutations and a reported DCM-associated mutation, R87Q.ResultsTwo TCAPmutations, T137I and R153H, were found in patients with HCM, and another TCAPmutation, E132Q, was identified in a patient with DCM. It was demonstrated by the qualitative assays that the HCM-associated mutations augment the ability of Tcap to interact with titin and calsarcin-1, whereas the DCM-associated mutations impair the interaction of Tcap with MLP, titin, and calsarcin-1.ConclusionsThese observations suggest that the difference in clinical phenotype (HCM or DCM) may be correlated with the property of altered binding among the Z-disc components

A novel high-throughput method for molecular serotyping and serotype-specific quantification of Streptococcus pneumoniae using a nanofluidic real-time PCR system

Serotype-specific quantification data are essential for elucidating the complex epidemiology of Streptococcus pneumoniae and evaluating pneumococcal vaccine efficacy. Various PCR-based assays have been developed to circumvent the drawback of labour-intensive and time-consuming culture-based procedures for serotype determination and quantification of pneumococcus. Here, we applied a nanofluidic real-time PCR system to establish a novel assay. Twenty-nine primer pairs, 13 of which were newly designed, were selected for the assay to cover 50 serotypes including all currently available conjugate and polysaccharide vaccine serotypes. All primer pairs were evaluated for their sensitivity, specificity, efficiency, repeatability, accuracy and reproducibility on the Fluidigm Biomark HD System, a nanofluidic real-time PCR system, by drawing standard curves with a serial dilution of purified DNA. We applied the assay to 52 nasopharyngeal swab samples from patients with pneumonia confirmed by chest X-ray to validate its accuracy. Minimum detection levels of this novel assay using the nanofluidic real-time PCR system were comparable to the conventional PCR-based assays (between 30 and 300 copies per reaction). They were specific to their targets with good repeatability (SD of copy number of 0.1), accuracy (within ±0.1 fold difference in log10 copy number) and reproducibility (SD of copy number of 0.1). When artificially mixed DNA samples consisting of multiple serotypes in various ratios were tested, all the serotypes were detected proportionally, including a minor serotype of one in 1000 copies. In the nasopharyngeal samples, the PCR system detected all the culturepositive samples and 22 out of 23 serotypes identified by the conventional method were matched with PCR results. We conclude that this novel assay, which is able to differentially quantify 29 pneumococcus groups for 45 test samples in a single run, is applicable to the large-scale epidemiological study of pneumococcus. We believe that this assay will facilitate our understanding of the roles of serotype-specific bacterial loads and implications of multiple serotype detections in pneumococcal diseases

Unique characteristics of new complete blood count parameters, the Immature Platelet Fraction and the Immature Platelet Fraction Count, in dengue patients

The advanced platelet parameters Immature Platelet Fraction and Immature Platelet Fraction Count have been implemented in clinical practice as measures of thrombopoietic activity, mainly in hematologic disorders that cause thrombocytopenia. The purpose of this observational study was to examine thrombopoiesis as reflected by these 2 new CBC parameters in patients infected with dengue. The study was conducted in infectious disease referral hospital in Metro Manila, the Philippines. We enrolled hospitalized patients at admission who were diagnosed with acute dengue or community acquired bacterial infection (CABI). Immature Platelet Fraction (IPF) and Immature Platelet Fraction Count were evaluated at admission and during hospitalization. A total of 606 patients were enrolled from May 1, 2017 to June 1, 2018. The participants consisted of 152 patients with dengue infection, 180 confirmed CABI, and 274 suspected CABI patients. At admission, the percent IPF (IPF%) of the patients with dengue was significantly higher than that of the confirmed CABI patients (median 3.7% versus 1.9%; p <0.001). In a time course evaluation, there was no significant difference of IPF% between the patients with dengue infection and the confirmed CABI patients in the febrile phase (median 1.9% versus 2.4%; p = 0.488), however, the IPF% of the patients with dengue infection increased to be significantly higher than that of the confirmed CABI patients in the critical phase (median 5.2% versus 2.2%; p <0.001). Our study elucidated the unique characteristics and time-course trends of IPF percent and number (IPF#) in the patients with dengue infection. IPF% and IPF# are potentially valuable parameters in dengue and further investigation is required for the optimal use in clinical practice

HLA-DRB1 and DQB1 alleles in Japanese type 1 autoimmune hepatitis: The predisposing role of the DR4/DR8 heterozygous genotype

ObjectiveAutoimmune hepatitis (AIH) is a chronic progressive liver disease. AIH is composed predominantly of type 1 in Japanese populations. The genetic and environmental factors are associated with the pathogenesis of AIH. HLA-DRB1*03:01 and *04:01 are associated with type 1 AIH in European and *04:05 in Japanese populations. Here, we conducted an HLA association study in order to find HLA alleles or haplotypes predisposing or protective for Japanese AIH.MethodsHLA-DRB1 and DQB1 genotyping of 360 type 1 AIH patients and 1026 healthy controls was performed.ResultsThe predisposing association of DRB1*04:01 (P = 0.0006, corrected P [Pc] = 0.0193, odds ratio [OR] 2.97, 95% confidence interval [CI] 1.62–5.43), DRB1*04:05 (P = 1.89×10−21, Pc = 5.86×10−20, OR 3.41, 95% CI 2.65–4.38), and DQB1*04:01 (P = 4.66×10−18, Pc = 6.99×10−17, OR 3.89, 95% CI 2.84–5.33) and the protective association of DRB1*13:02 (P = 0.0003, Pc = 0.0080, OR 0.48, 95% CI 0.32–0.72) with Japanese type 1 AIH were observed. An association of the DR4/DR8 heterozygous genotype with Japanese AIH was identified for the first time (P = 3.12×10−9, OR 3.52, 95% CI 2.34–5.29). Susceptible diplotypes were DRB1*04:05-DQB1*04:01/DRB1*08:02-DQB1*03:02 (P = 0.0004, OR 24.77, 95% CI 1.45–424.31) and DRB1*04:05-DQB1*04:01/DRB1*08:03-DQB1*06:01 (P = 1.18×10−6, OR 10.64, 95% CI 3.19–35.46). Serum levels of Immunoglobulin G and Immunoglobulin M, International Autoimmune Hepatitis Group score, positive rate of anti-smooth muscle antibodies, and the rate of definite AIH were higher in AIH patients with DRB1*04:05 than without.ConclusionsThe important roles of specific combinations of DRB1 and DQB1 alleles or haplotypes in the pathogenesis of type 1 AIH were suggested. The association of DR4/DR8 heterozygous genotype suggested the pathologic importance of trans-complementing DQα-β heterodimer molecules encoded by DQA1 allele of one haplotype and the DQB1 allele of the other haplotype, as it was proposed in the HLA association studies of Type 1 diabetes

ベトナムにおいて父親のたばこ煙の暴露は、下気道呼吸器感染症による小児入院リスクを上げるが、それ以外の疾患への影響はない

Exposure to environmental tobacco smoke (ETS) is an important modifiable risk factor for child hospitalization, although its contribution is not well documented in countries where ETS due to maternal tobacco smoking is negligible. We conducted a birth cohort study of 1999 neonates between May 2009 and May 2010 in Nha Trang, Vietnam, to evaluate paternal tobacco smoking as a risk factor for infectious and non-infectious diseases. Hospitalizations during a 24-month observation period were identified using hospital records. The effect of paternal exposure during pregnancy and infancy on infectious disease incidence was evaluated using Poisson regression models. In total, 35.6% of 1624 children who attended follow-up visits required at least one hospitalization by 2 years of age, and the most common reason for hospitalization was lower respiratory tract infection (LRTI). Paternal tobacco smoking independently increased the risk of LRTI 1.76-fold (95% CI: 1.24?2.51) after adjusting for possible confounders but was not associated with any other cause of hospitalization. The population attributable fraction indicated that effective interventions to prevent paternal smoking in the presence of children would reduce LRTI-related hospitalizations by 14.8% in this epidemiological setting.長崎大学学位論文 学位記番号:博(医歯薬)甲第995号 学位授与年月日:平成29年9月6日Author: Reiko Miyahara, Kensuke Takahashi, Nguyen Thi Hien Anh, Vu Dinh Thiem, Motoi Suzuki, Hiroshi Yoshino, Le Huu Tho, Hiroyuki Moriuchi, Sharon E. Cox, Lay Myint Yoshida, Dang Duc Anh, Koya Ariyoshi & Michio YasunamiCitation: Scientific Reports, 7, 45481; 2017Nagasaki University (長崎大学)課程博