BackgroundGlucose-6-phosphate dehydrogenase (G6PD) deficiency is particularly prevalent in historically malaria-endemic countries. Although most individuals with G6PD deficiency are asymptomatic, deficiency can result in acute haemolytic anaemia after exposure to oxidative agents. A reliable test is necessary for diagnosing the deficiency to prevent an acute haemolytic crisis following, for example, anti-malarial treatment. The aim of this study was to investigate which method was the best predictor of this disorder.MethodsThe present study investigated four G6PD activity detections (fluorescence spot (FS), methaemoglobin reduction (MR), biochemical and cytochemical test). These methods accompanied with mutation analysis of blood samples were taken from 295 apparently healthy individuals with unknown G6PD deficiency status.ResultsMolecular characterization of 295 Thai adults revealed an overall prevalence of 14.2%. The G6PD Viangchan (871 G>A) was the most common (83.3%), followed by G6PD Mahidol (487G>A) (11.9%), and G6PD Union (1360 C>T) (4.8%). There were two cases of G6PD deficiency carrying the double mutations of Viangchan (871G > A)-Mahidol (487G > A) and Viangchan (871G > A)-Union (1360C > T). In comparison, the prevalence of G6PD deficiency was 6.1% by FS test and 7.1% by MR test. G6PD activity was 11 ± 2.5 IU/gHb in non-deficient females (mean ± SD), and 10.9 ± 0.6 IU/gHb in non-deficient males. The upper and lower limit cut-off points for partial and severe deficiency in adults were 5.7 IU/gHb (60% of the normal mean) and 0.95 IU/gHb (10% of the normal mean), respectively. All hemizygote, homozygote and double mutations were associated with severe enzyme deficiency (the residual enzyme activity <10% of the normal mean), whereas only 14.3% of the heterozygote mutations showed severe enzyme deficiency. Based on the cut-off value <5.7 IU/gHb, the quantitative G6PD assay diagnosed 83% of cases as G6PD-deficient. Using a cut-off number of negative cell >20% in the cytochemical assay to define G6PD deficiency, the prevalence of G6PD deficiency was closest to the molecular analysis (12.9% G6PD-deficient) compared to the others methods.ConclusionThe cytochemical method is a significant predictor of this disease, while FS and MR test are recommended for the detection of severe G6PD deficiency in developing countries.

Blastocystis sp. is a common zoonotic intestinal protozoa which has been classified into 17 subtypes (STs). A cross-sectional study was conducted to determine the prevalence and subtype distribution of Blastocystis in villagers living on the Thai-Myanmar border, where the risk of parasitic infection is high. A total of 207 stool samples were collected and DNA was extracted. PCR and sequencing using primers targeting small-subunit ribosomal RNA (SSU rRNA) gene were performed. The prevalence of Blastocystis infection was 37.2% (77/207). ST3 (19.8%; 41/207) was the predominant subtype, followed by ST1 (11.6%; 24/207), ST2 (5.3%; 11/207), and ST4 (0.5%; 1/207). A phylogenetic tree was reconstructed using the maximum likelihood (ML) method based on the Hasegawa-Kishino-Yano + G + I model. The percentage of bootstrapped trees in which the associated taxa clustered together was relatively high. Some sequences of Blastocystis positive samples (TK18, 39, 46, 71, and 90) were closely related to animals (pig and cattle) indicating zoonotic risks. Therefore, proper health education in parasitic prevention for the villagers should be promoted to improve their personal hygiene. Further longitudinal studies are required to monitor the prevalence of parasitic infections after providing health education and to investigate Blastocystis ST in animals living in these villages.

In response to oxidative stress and during apoptosis, cells often shed microparticles (MPs), submicron elements carrying phosphatidylserine and protein antigens. Glucose-6-phosphate dehydrogenase (G6PD)-deficient cells are extremely sensitive to oxidative damage that may lead to the formation of MPs. To determine whether G6PD deficiency alters membrane phospholipid asymmetry and increases MPs production, we determined the concentrations and cellular origins of MPs in G6PD-deficient individuals using flow cytometry. G6PD-deficient individuals showed an increase in circulating MPs concentrations as compared with G6PD-normal individuals [1051/μL (865-2532/μL) vs. 258/μL (235-575/μL), P < 0.01]. MPs concentrations were significantly increased with the severity of G6PD deficiency. Median MPs concentrations from individuals with severe G6PD deficiency, and individuals with moderate G6PD deficiency were 2567/μL (1216-2532/μL) and 984/μL (685-2107/μL), respectively (P < 0.01). Importantly, G6PD enzymatic activity was significantly correlated with MPs concentrations with r(2) = 0.731. MPs found in G6PD deficiency individuals were largely derived from red blood cells (RBCs) (45%) and platelets (30%). Additionally, Atomic Force Microscopy was used to study the morphology and measures the diameter of MPs found in G6PD-deficient individuals. The mean (SD) width and height of RMPs were 0. 41 (0.18) and 2.04 (0.14) μm, respectively. Together, these results indicate that MP concentration is significantly correlated with G6PD enzymatic activity and is increased in G6PD-deficient as compared with G6PD-normal individuals. Our data also provide an evidence for an alteration in cell membrane associated with a decreased in G6PD activity. However, the significance of MPs in G6PD deficiency needs further clarification.

Yoga and tai chi exercises can be used as components of a strategy to promote healthy lifestyles (balanced diet and moderate intensity exercise) in vulnerable populations, such as menopausal women, in order to prevent aging induced oxidative stress-related diseases.

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