Rapid identification of chloroquine and atovaquone drug resistance in Plasmodium falciparum using high-resolution melt polymerase chain reaction

<p>Abstract</p> <p>Background</p> <p>Drug resistance determination for <it>Plasmodium falciparum </it>infections are important to determining the type of treatment to be given. Besides <it>in vivo </it>experiments, molecular methods, such as sequencing and PCR, are now increasingly being used. Here a cheaper alternative to sequencing or the use of multiplex 5'nuclease PCR assay for detection and differentiation of drug resistance haplotypes for chloroquine and atovaquone using polymerase chain reaction-high resolution melt (PCR-HRM) is reported.</p> <p>Methods</p> <p>Separate PCR-HRM assays were designed for the detection and differentiation of chloroquine and atovaquone drug resistance haplotypes in <it>P. falciparum</it>. PCR was conducted on a thermal cycler and melt curves generated using a LightScanner. These were tested against reference strains of <it>P. falciparum </it>from MR4 as well as 53 local isolates.</p> <p>Results</p> <p>The PCR-HRM assays are able to detect and differentiate between the various haplotypes consistently. These assays can also be used to detect new variants.</p> <p>Conclusions</p> <p>PCR-HRM is an inexpensive option for the determination of drug resistance profile in <it>P. falciparum </it>and will see increasing use as an alternative to sequencing and 5'nuclease PCR assays in reference laboratories or once PCR systems that are able to conduct HRM become commonplace.</p

Japanese Encephalitis, Singapore

10.3201/eid1203.051251Emerging Infectious Diseases123525-52

Effectiveness of Pandemic H1N1-2009 Vaccination in Reducing Laboratory Confirmed Influenza Infections among Military Recruits in Tropical Singapore

10.1371/journal.pone.0026572PLoS ONE610

Naturally Acquired Human Plasmodium knowlesi Infection, Singapore

Naturally Acquired Human Plasmodium knowlesi Infection, Singapor

Differing clinical characteristics between influenza strains among young healthy adults in the tropics

<p>Abstract</p> <p>Background</p> <p>Influenza infections may result in different clinical presentations. This study aims to determine the clinical differences between circulating influenza strains in a young healthy adult population in the tropics.</p> <p>Methods</p> <p>A febrile respiratory illness (FRI) (fever ≥ 37.5°C with cough and/or sore throat) surveillance program was started in 4 large military camps in Singapore on May 2009. Personnel with FRI who visited the camp clinics from 11 May 2009 to 25 June 2010 were recruited. Nasal washes and interviewer-administered questionnaires on demographic information and clinical features were obtained from consenting participants. All personnel who tested positive for influenza were included in the study. Overall symptom load was quantified by counting the symptoms or signs, and differences between strains evaluated using linear models.</p> <p>Results</p> <p>There were 434 (52.9%) pandemic H1N1-2009, 58 (7.1%) seasonal H3N2, 269 (32.8%) influenza B, and 10 (1.2%) seasonal H1N1 cases. Few seasonal influenza A (H1N1) infections were detected and were therefore excluded from analyses, together with undetermined influenza subtypes (44 (1.5%)), or more than 1 co-infecting subtype (6 (0.2%)). Pandemic H1N1-2009 cases had significantly fewer symptoms or signs (mean 7.2, 95%CI 6.9-7.4, difference 1.6, 95%CI 1.2-2.0, <it>p </it>< 0.001) than the other two subtypes (mean 8.7, 95%CI 8.5-9.0). There were no statistical differences between H3N2 and influenza B (<it>p </it>= 0.58). Those with nasal congestion, rash, eye symptoms, injected pharynx or fever were more likely to have H3N2; and those with sore throat, fever, injected pharynx or rhinorrhoea were more likely to have influenza B than H1N1-2009.</p> <p>Conclusions</p> <p>Influenza cases have different clinical presentations in the young adult population. Pandemic H1N1 influenza cases had fewer and milder clinical symptoms than seasonal influenza. As we only included febrile cases and had no information on the proportion of afebrile infections, further research is needed to confirm whether the relatively milder presentation of pandemic versus seasonal influenza infections applies to all infections or only febrile illnesses.</p

A clinical diagnostic model for predicting influenza among young adult military personnel with febrile respiratory illness in Singapore

10.1371/journal.pone.0017468PLoS ONE63

Respiratory viral pathogens among Singapore military servicemen 2009 - 2012: Epidemiology and clinical characteristics

10.1186/1471-2334-14-204BMC Infectious Diseases141-BIDM

Effects of Anacetrapib in Patients with Atherosclerotic Vascular Disease

BACKGROUND: Patients with atherosclerotic vascular disease remain at high risk for cardiovascular events despite effective statin-based treatment of low-density lipoprotein (LDL) cholesterol levels. The inhibition of cholesteryl ester transfer protein (CETP) by anacetrapib reduces LDL cholesterol levels and increases high-density lipoprotein (HDL) cholesterol levels. However, trials of other CETP inhibitors have shown neutral or adverse effects on cardiovascular outcomes. METHODS: We conducted a randomized, double-blind, placebo-controlled trial involving 30,449 adults with atherosclerotic vascular disease who were receiving intensive atorvastatin therapy and who had a mean LDL cholesterol level of 61 mg per deciliter (1.58 mmol per liter), a mean non-HDL cholesterol level of 92 mg per deciliter (2.38 mmol per liter), and a mean HDL cholesterol level of 40 mg per deciliter (1.03 mmol per liter). The patients were assigned to receive either 100 mg of anacetrapib once daily (15,225 patients) or matching placebo (15,224 patients). The primary outcome was the first major coronary event, a composite of coronary death, myocardial infarction, or coronary revascularization. RESULTS: During the median follow-up period of 4.1 years, the primary outcome occurred in significantly fewer patients in the anacetrapib group than in the placebo group (1640 of 15,225 patients [10.8%] vs. 1803 of 15,224 patients [11.8%]; rate ratio, 0.91; 95% confidence interval, 0.85 to 0.97; P=0.004). The relative difference in risk was similar across multiple prespecified subgroups. At the trial midpoint, the mean level of HDL cholesterol was higher by 43 mg per deciliter (1.12 mmol per liter) in the anacetrapib group than in the placebo group (a relative difference of 104%), and the mean level of non-HDL cholesterol was lower by 17 mg per deciliter (0.44 mmol per liter), a relative difference of -18%. There were no significant between-group differences in the risk of death, cancer, or other serious adverse events. CONCLUSIONS: Among patients with atherosclerotic vascular disease who were receiving intensive statin therapy, the use of anacetrapib resulted in a lower incidence of major coronary events than the use of placebo. (Funded by Merck and others; Current Controlled Trials number, ISRCTN48678192 ; ClinicalTrials.gov number, NCT01252953 ; and EudraCT number, 2010-023467-18 .)

Plant diversity studies and selection for transgenic production of biopolymers

Genetic engineering and biotechnology hold great potential for plant breeding as it promises to expedite the time taken to produce crop varieties with desirable characters. With the use of molecular techniques, it would now be possible to hasten the transfer of desirable genes among varieties and to introduce novel genes from related wild species. This highlights the importance of genetic diversity and the need for conserved germplasm. Assisting in selection for desirable characters as well as plant identification are the use of techniques such as molecular markers for genetic mapping and genetic diversity studies of valuable crop plants and ornamental plants. In this study, amplified fragment length polymorphism (AFLP) was used for genetic diversity studies into Caladium, Xanthosoma, cassava, bamboo and banana. Results showed that it was effective in differentiating plants down to the cultivar level. The high level of polymorphism detected using AFLP means accurate phylogenetic analyses could also be obtained. Proper identification and taxonomic classification of plant species using AFLP data was also demonstrated. In addition to genetic diversity studies, work was also done to establish the basis for the engineering of tropical plants for PHB production. This included the development of gene constructs, PCR assays, attempts to detect transient levels of PHB via epifluorescence, establishment of regeneration system for cassava, tests of antibiotics and herbicide tolerance levels as well as preliminary particle bombardment experiments in tobacco and cassava.Master of Scienc