Publications by authors named "Andrew Masta"

Dogs were the first domesticated species, originating at least 15,000 y ago from Eurasian gray wolves. Dogs today consist primarily of two specialized groups--a diverse set of nearly 400 pure breeds and a far more populous group of free-ranging animals adapted to a human commensal lifestyle (village dogs). Village dogs are more genetically diverse and geographically widespread than purebred dogs making them vital for unraveling dog population history.

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It has been estimated that there are more than 60 million Hepatitis C virus (HCV) carriers in the World Health Organisation's Western Pacific region (WHO-WPR), where liver cancer is among the top three causes of cancer death. WHO and the US Centres for Disease Control and Prevention report the prevalence of HCV in the South Pacific islands (countries within the WHO-WPR) to be high (5-10% and >2% respectively). However, since HCV is not tested for in many of these countries, there is sparse data available to support this assertion.

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Hepatitis B virus (HBV) genomes are small, semi-double-stranded DNA circular genomes that contain alternating overlapping reading frames and replicate through an RNA intermediary phase. This complex biology has presented a challenge to estimating an evolutionary rate for HBV, leading to difficulties resolving the evolutionary and epidemiological history of the virus. Here, we re-examine rates of HBV evolution using a novel data set of 112 within-host, transmission history (pedigree) and among-host genomes isolated over 20 years from the indigenous peoples of the South Pacific, combined with 313 previously published HBV genomes.

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Background: Sexually transmissible infections (STI) are common in female sex workers (FSW).

Aim: To determine if 3-monthly periodic presumptive treatments (PPT) would reduce the prevalence of STI in FSW.

Methods: In a cohort study conducted between November 2003 and September 2004, FSW were enrolled, counselled and interviewed.

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Background: Sexually transmissible infections (STIs) are common in female sex workers (FSWs), most of which are asymptomatic and therefore under-reported. Our aim was to determine the sensitivity and specificity of reported symptoms obtained via questionnaire augmented with leukocyte esterase (LE) urine dipstick test for the detection of Chlamydia trachomatis (Ct), Neisseria gonorrhea (Ng) and Trichomonas vaginalis (Tv) detected using polymerase chain reaction (PCR).

Methods: In November 2003, a cohort of FSWs was screened for STIs and completed a questionnaire.

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Background: The use of anti-malarial drug combinations with artemisinin or with one of its derivatives is now widely recommended to overcome drug resistance in falciparum as well as vivax malaria. The fixed oral dose artemisinin-naphthoquine combination (ANQ, ARCO) is a newer artemisinin-based combination (ACT) therapy undergoing clinical assessment. A study was undertaken to assess the safety, efficacy and tolerability of ANQ combination in areas of multi-drug resistance to generate preliminary baseline data in adult population of Papua New Guinea.

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Urinary Iodine excretion is a useful and important indicator of the iodine status of a population. This study attempts to determine the urinary iodine concentration of non-pregnant, pregnant and lactating women, resident in the National Capital District of Papua New Guinea, so as to evaluate their status of iodine nutrition. The study population was made up of 56 non-pregnant, 40 lactating and 212 pregnant women.

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Malnutrition is a contributing cause of about half of the 10 million deaths annually worldwide, and contributes to a substantial proportion of the infectious disease morbidity among children in developing countries. Recent epidemiological and clinical evidence has shown that in most developing countries deficiencies of specific micronutrients are partly responsible for the severity of infectious disease morbidity and mortality in malnourished children. Efforts to improve micronutrient status have focused on iron, vitamin A and iodine.

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The N86Y mutation in pfmdr1 is reported to play an additional role for the chloroquine resistance in Plasmodium falciparum isolates. However, not much has been done to clarify whether this mutation augments the level of chloroquine resistance in the isolates harboring pfcrt K76T mutation. We compared the in vitro chloroquine efficacy between pfcrt K76T mutant parasites with or without N86Y mutation from Papua New Guinea.

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The 27-bp deletion in the erythrocyte band 3 gene (B3Delta27) constitutes a genetic basis for Southeast Asian and Melanesian ovalocytosis. The distribution of B3Delta27 has been interpreted to reflect malaria selection or dispersal of the recent expansion of Austronesian-speaking populations. To explore these two hypotheses, we examined eight malarious populations of the East Sepik Province of Papua New Guinea (PNG) that speak both the Austronesian and Papuan languages.

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The cytochrome P450 (CYP) isozyme CYP2C19 metabolizes clinically important drugs, including the anti-malarial proguanil currently used for multi-drug resistant Plasmodium falciparum malaria. CYP2C19 activity varies among geographical regions due to high frequencies of two null alleles (CYP2C19*2/*3) in Asian and especially Pacific populations. Previously, we reported an unprecedentedly high frequency of CYP2C19 poor metabolizers (PM) within populations of Vanuatu, which suggested even higher PM frequencies in Papua New Guinea.

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The distribution of microorganisms in the subsurfaces of hydrothermal vents was investigated by using subvent rock core samples. Microbial cells and ATP were detected from cores taken at depths of less than 99.4 and 44.

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