Some aspects of visual functions and serum retinol levels in young adults and middle aged subjects

The comparism of the dark adaptation and plasma retinol level (Vitamin A) was a potentially useful method of studying the basic nature of the aging process in vision. The purpose of this study was to determine the effect of age upon the dark adaptation time and plasma retinol level. Dark adaptation time, visual fields and plasma retinol levels were studied in two different age groups of Myanmar subjects (young adults: 18-25 years and middle-aged subjects: 40-60 years) (n=30 each). Dark adaptation time (DAT) was determined by a rapid dark adaptation test adopted from Thornton (1977). Visual field was assessed by manually setting kinetic perimetry. Plasma retinol level was determined by colorimetric method using trifluoroacetic acid (TFA). None of the subjects exhibited subnormal plasma retinol levels. Although the plasma retinol levels of middle-aged subjects were comparable to those of their younger counterparts (66.3 (5.2) µg/dl vs 61.4(8.1) µg/dl) (mean(SD)), the middle-aged subjects had significantly longer DAT (5.7 (1.4) vs 3.6 (1.3) minutes; P<0.05) and significantly greater reduction (P<0.05) in visual fields of both eyes. There was a significant negative correlation (P<0.05) between plasma retinol level and DAT in the middle-aged subjects, but not in young adults. No correlation was found between serum retinol level and visual field reduction in both groups. Even with comparable plasma retinol level, longer DAT and greater reduction of visual field in middle-aged subjects indicated that retinal function might also be affected by the age-related changes in retina. Keywords: Dark Adaptation Time (DAT), Rapid Dark Adaptation Test, Vitamin A, Visual Field, Aging

Is Plasmodium vivax a severe malaria?: a systematic review and meta-analysis

Background: Plasmodium vivax is one of the major species of malaria infecting humans. Although emphasis on P. falciparum is appropriate, the burden of vivax malaria should be given due attention. This study aimed to synthesize the evidence on severe malaria in P. vivax infection compared with that in P. falciparum infection. Methods/Principal Findings: We searched relevant studies in electronic databases. The main outcomes required for inclusion in the review were mortality, severe malaria (SM) and severe anaemia (SA). The methodological quality of the included studies was assessed using the Newcastle-Ottawa Scale. Overall, 26 studies were included. The main meta-analysis was restricted to the high quality studies. Eight studies (n = 27490) compared the incidence of SM between P. vivax infection and P. falciparum mono-infection; a comparable incidence was found in infants (OR: 0.45, 95% CI:0.04-5.68, I2:98%), under 5 year age group (OR: 2.06, 95% CI: 0.83-5.1, I2:83%), the 5-15 year-age group (OR: 0.6, 95% CI: 0.31-1.16, I2:81%) and adults (OR: 0.83, 95% CI: 0.67-1.03, I2:25%). Six studies reported the incidences of SA in P. vivax infection and P. falciparum mono-infection; a comparable incidence of SA was found among infants (OR: 3.47, 95%:0.64-18.94, I2: 92%), the 5-15 year-age group (OR:0.71, 95% CI: 0.06-8.57, I2:82%). This was significantly lower in adults (OR:0.75, 95% CI: 0.62-0.92, I2:0%). Five studies (n = 71079) compared the mortality rate between vivax malaria and falciparum malaria. A lower rate of mortality was found in infants with vivax malaria (OR:0.61, 95% CI:0.5-0.76, I2:0%), while this was comparable in the 5-15 year- age group (OR: 0.43, 95% CI:0.06-2.91, I2:84%) and the children of unspecified-age group (OR: 0.77, 95% CI:0.59-1.01, I2:0%). Conclusion: Overall, the present analysis identified that the incidence of SM in patients infected with P. vivax was considerable, indicating that P. vivax is a major cause of SM. Awareness of the clinical manifestations of vivax malaria should prompt early detection. Subsequent treatment and monitoring of complications can be life-saving

Transcriptome profiling of staphylococcus aureus associated extracellular vesicles reveals presence of small RNA-cargo

Bacterial extracellular vesicles (EVs) have a vital role in bacterial pathogenesis. However, to date, the small RNA-cargo of EVs released by the opportunistic pathogen Staphylococcus aureus has not been characterized. Here, we shed light on the association of small RNAs with EVs secreted by S. aureus MSSA476 cultured in iron-depleted bacteriologic media supplemented with a subinhibitory dosage of vancomycin to mimic infection condition. Confocal microscopy analysis on intact RNase-treated EVs indicated that RNA is associated with EV particles. Transcriptomic followed by bioinformatics analysis of EV-associated RNA revealed the presence of potential gene regulatory small RNAs and high levels of tRNAs. Among the EV-associated enriched small RNAs were SsrA, RsaC and RNAIII. Our finding invites new insights into the potential role of EV-associated RNA as a modulator of host-pathogen interaction. Introductio

Spatial distribution, work patterns, and perception towards malaria interventions among temporary mobile/migrant workers in artemisinin resistance containment zone

BACKGROUND: Mobile populations are at a high risk of malaria infection and suspected to carry and spread resistant parasites. The Myanmar National Malaria Control Programme focuses on preventive interventions and vector control measures for the temporary mobile/migrant workers in Myanmar Artemisinin Resistance Containment Zones. METHODS: A prospective cross-sectional study was conducted in 2012 in Kawthaung and Bokepyin townships of Tanintharyi Region, Myanmar, covering 192 mobile/migrant aggregates. The objectives were to identify the spatial distribution of the mobile/migrant populations, and to assess knowledge, attitudes, perceptions, and practices concerning malaria prevention and control, and their preferred methods of interventions. The structure of the192 migrant aggregates was investigated using a migrant mapping tool. Individual and household information was collected by structured interviews of 408 respondents from 39 aggregates, supplemented by 12 in-depth interviews of health care providers, authorities, volunteers, and employers. Data were analyzed by triangulating quantitative and qualitative data. RESULTS: The primary reasons for the limitation in access to formal health services for suspected malaria within 24 hours were identified to be scattered distribution of migrant aggregates, variable working hours and the lack of transportation. Only 19.6% of respondents reported working at night from dusk to dawn. Among study populations, 73% reported a perceived risk of contracting malaria and 60% reported to know how to confirm a suspected case of malaria. Moreover, only 15% was able to cite correct antimalarial drugs, and less than 10% believed that non-compliance with antimalarial treatment may be related to the risk of drug resistance. About 50% of study population reported to seeking health care from the public sector, and to sleep under ITNs/LLINs the night before the survey. There was a gap in willingness to buy ITNs/LLINs and affordability (88.5% vs. 60.2%) which may affect their sustained and consistent use. Only 32.4% across all aggregates realized the importance of community participation in effective malaria prevention and control. CONCLUSIONS: Community-based innovative approaches through strong collaboration and coordination of multi-stakeholders are desirable for relaying information on ITNs/LLINs, rapid diagnostic test, and artemisinin combination therapy and drug resistance successfully across the social and economic diversity of mobile/migrant aggregates in Myanmar

Malaria and soil-transmitted intestinal helminth co-infection and its effect on anemia: a meta-analysis

This study aimed to synthesize available evidence on the extent of malaria and soil-transmitted intestinal helminth (STH) co-infections in people living in endemic countries and to explore the effect of interactions between malaria and STHs on anemia. We searched relevant studies in electronic databases up to March 2013. Studies comparing malaria and STH co-infected patients with those not co-infected were included and the effect estimates were pooled using a random-effects model. We identified 30 studies for meta-analyses of which 17 were cross-sectional design. The majority of included studies (80%) were carried out in African countries. Among pregnant women, those infected with hookworm were found to have higher association with malaria infection compared with those without (summary OR: 1.36; 95% CI: 1.17-1.59; I2: 0%). Among non-pregnant adults, the summary OR of the association between anemia and the combined malaria and STH was 2.91 (1.38-6.14). The summary OR of the association between anemia and malaria alone was 1.53 (0.97-2.42), while the association between anemia and STH alone was 0.28 (0.04-1.95). There is no good evidence to support a different effect of malaria and STH on anemia. A subgroup analysis showed a higher risk of malaria infection in the primigravidae (summary OR: 1.61; 95% CI: 1.3-1.99; I2: 0%). In conclusion, the malaria-STH co-infection was variable with complex outcomes on anemi

Outer membrane vesicle-mediated release of cytolethal distending toxin (CDT) from Campylobacter jejuni

<p>Abstract</p> <p>Background</p> <p>Background: Cytolethal distending toxin (CDT) is one of the well-characterized virulence factors of <it>Campylobacter jejuni</it>, but it is unknown how CDT becomes surface-exposed or is released from the bacterium to the surrounding environment.</p> <p>Results</p> <p>Our data suggest that CDT is secreted to the bacterial culture supernatant via outer membrane vesicles (OMVs) released from the bacteria. All three subunits (the CdtA, CdtB, and CdtC proteins) were detected by immunogold labeling and electron microscopy of OMVs. Subcellular fractionation of the bacteria indicated that, apart from the majority of CDT detected in the cytoplasmic compartment, appreciable amounts (20-50%) of the cellular pool of CDT proteins were present in the periplasmic compartment. In the bacterial culture supernatant, we found that a majority of the extracellular CDT was tightly associated with the OMVs. Isolated OMVs could exert the cell distending effects typical of CDT on a human intestinal cell line, indicating that CDT is present there in a biologically active form.</p> <p>Conclusion</p> <p>Our results strongly suggest that the release of outer membrane vesicles is functioning as a route of <it>C. jejuni </it>to deliver all the subunits of CDT toxin (CdtA, CdtB, and CdtC) to the surrounding environment, including infected host tissue.</p

Studies on a Novel Serine Protease of a ΔhapAΔprtV Vibrio cholerae O1 Strain and Its Role in Hemorrhagic Response in the Rabbit Ileal Loop Model

BACKGROUND: Two well-characterized proteases secreted by Vibrio cholerae O1 strains are hemagglutinin protease (HAP) and V. cholerae protease (PrtV). The hapA and prtV knock out mutant, V. cholerae O1 strain CHA6.8ΔprtV, still retains residual protease activity. We initiated this study to characterize the protease present in CHA6.8ΔprtV strain and study its role in pathogenesis in rabbit ileal loop model (RIL). METHODOLOGY/PRINCIPAL FINDINGS: We partially purified the residual protease secreted by strain CHA6.8ΔprtV from culture supernatant by anion-exchange chromatography. The major protein band in native PAGE was identified by MS peptide mapping and sequence analysis showed homology with a 59-kDa trypsin-like serine protease encoded by VC1649. The protease activity was partially inhibited by 25 mM PMSF and 10 mM EDTA and completely inhibited by EDTA and PMSF together. RIL assay with culture supernatants of strains C6709 (FA ratio 1.1+/-0.3 n = 3), CHA6.8 (FA ratio 1.08+/-0.2 n = 3), CHA6.8ΔprtV (FA ratio 1.02+/-0.2 n = 3) and partially purified serine protease from CHA6.8ΔprtV (FA ratio 1.2+/-0.3 n = 3) induced fluid accumulation and histopathological studies on rabbit ileum showed destruction of the villus structure with hemorrhage in all layers of the mucosa. RIL assay with culture supernatant of CHA6.8ΔprtVΔVC1649 strain (FA ratio 0.11+/-0.005 n = 3) and with protease incubated with PMSF and EDTA (FA ratio 0.3+/-0.05 n = 3) induced a significantly reduced FA ratio with almost complete normal villus structure. CONCLUSION: Our results show the presence of a novel 59-kDa serine protease in a ΔhapAΔprtV V. cholerae O1 strain and its role in hemorrhagic response in RIL model

National scale-up of tuberculosis-human immunodeficiency virus collaborative activities in Myanmar from 2005 to 2016 and tuberculosis treatment outcomes for patients with human immunodeficiency virus-positive tuberculosis in the Mandalay Region in 2015.

Background: HIV-associated TB is a serious public health problem in Myanmar. Study objectives were to describe national scale-up of collaborative activities to reduce the double burden of TB and HIV from 2005 to 2016 and to describe TB treatment outcomes of individuals registered with HIV-associated TB in 2015 in the Mandalay Region. Methods: Secondary analysis of national aggregate data and, for treatment outcomes, a cohort study of patients with HIV-associated TB in the Mandalay Region. Results: The number of townships implementing collaborative activities increased from 7 to 330 by 2016. The number of registered TB patients increased from 1577 to 139 625 in 2016, with the number of individuals tested for HIV increasing from 432 to 114 180 (82%) in 2016: 10 971 (10%) were diagnosed as HIV positive. Uptake of co-trimoxazole preventive therapy (CPT) and antiretroviral therapy (ART) nationally in 2016 was 77% and 52%, respectively. In the Mandalay Region, treatment success was 77% and mortality was 18% in 815 HIV-associated TB patients. Risk factors for unfavourable outcomes and death were older age (≥45 years) and not taking CPT and/or ART. Conclusion: Myanmar is making good progress with reducing the HIV burden in TB patients, but better implementation is needed to reach 100% HIV testing and 100% CPT and ART uptake in TB-HIV co-infected patients

Trend of Human Papillomavirus Genotypes in Cervical Neoplasia Observed in a Newly Developing Township in Yangon, Myanmar

Persistent infection with oncogenic types of human papillomavirus (HPV) is the most important risk factor associated with cervical cancer. This study detected the oncogenic HPV genotypes in cervical neoplasia in relation to clinicopathological findings using a cross-sectional descriptive method in 2011 and 2012. Cervical swabs and colposcopy-directed cervical biopsy tissues were collected from 108 women (median age 45 years;range 20-78) showing cervical cytological changes at Sanpya General Hospital, Yangon, Myanmar. HPV DNA testing and genotyping were performed by polymerase chain reaction and restriction fragment length polymorphism. HPV was identified in women with cervical intraepithelial neoplasia (CIN) 1 (44.4%), CIN2 (63.2%), CIN3 (70.6%), and squamous cell carcinoma (SCC) (74.1%). The association between cervical neoplasia and HPV positivity was highly significant (p＝0.008). Most patients infected with HPV were between 40-49 years of age, and the youngest were in the 20- to 29-year-old age group. The most common genotype was HPV 16 (65.6%) with the following distribution:70% in CIN1, 41.7% in CIN2, 91.7% in CIN3, and 60% in SCC. HPV-31 was the second-most frequent (21.9%):30% in CIN1, 33.3% in CIN2, 8.3% in CIN3, and 15% in SCC. The third-most frequent-genotype was HPV-18 (7.8%):8.3% in CIN1, and 20% in SCC. Another genotype was HPV-58 (4.7%):16.7% in CIN1 and 5% in SCC. The majority of CIN/SCC cases were associated with HPV genotypes 16, 31, 18, and 58. If oncogenic HPV genotypes are positive, the possibility of cervical neoplasia can be predicted. Knowledge of the HPV genotypes distribution can predict the effectiveness of the currently used HPV vaccine