Temporal changes in genetic diversity of msp-1, msp-2, and msp-3 in Plasmodium falciparum isolates from Grande Comore Island after introduction of ACT.

BACKGROUND: Malaria is still one of the serious public health problems in Grande Comore Island, although the number of annual cases has been greatly reduced in recent years. A better understanding of malaria parasite population diversity and transmission dynamics is critical for assessing the effectiveness of malaria control measures. The objective of this study is to investigate temporal changes in genetic diversity of Plasmodium falciparum populations and multiplicity of infection (MOI) in Grande Comore 10 years after introduction of ACT. METHODS: A total of 232 P. falciparum clinical isolates were collected from the Grande Comore Island during two sampling periods (118 for 2006‒2007 group, and 114 for 2013‒2016 group). Parasite isolates were characterized for genetic diversity and complexity of infection by genotyping polymorphic regions in merozoite surface protein gene 1 (msp-1), msp-2, and msp-3 using nested PCR and DNA sequencing. RESULTS: Three msp-1 alleles (K1, MAD20, and RO33), two msp-2 alleles (FC27 and 3D7), and two msp-3 alleles (K1 and 3D7) were detected in parasites of both sampling periods. The RO33 allele of msp-1 (84.8%), 3D7 allele of msp-2 (90.8%), and K1 allele of msp-3 (66.7%) were the predominant allelic types in isolates from 2006-2007 group. In contrast, the RO33 allele of msp-1 (63.4%), FC27 allele of msp-2 (91.1%), and 3D7 allele of msp-3 (53.5%) were the most prevalent among isolates from the 2013-2016 group. Compared with the 2006‒2007 group, polyclonal infection rates of msp-1 (from 76.7 to 29.1%, P < 0.01) and msp-2 (from 62.4 to 28.3%, P < 0.01) allelic types were significantly decreased in those from 2013‒2016 group. Similarly, the MOIs for both msp-1 and msp-2 were higher in P. falciparum isolates in the 2006-2007 group than those in 2013-2016 group (MOI = 3.11 vs 1.63 for msp-1; MOI = 2.75 vs 1.35 for msp-2). DNA sequencing analyses also revealed reduced numbers of distinct sequence variants in the three genes from 2006‒2007 to 2013‒2016: msp-1, from 32 to 23 (about 28% decline); msp-2 from 29 to 21 (about 28% decline), and msp-3 from 11 to 3 (about 72% decline). CONCLUSIONS: The present data showed dramatic reduction in genetic diversity and MOI among Grande Comore P. falciparum populations over the course of the study, suggesting a trend of decreasing malaria transmission intensity and genetic diversity in Grande Comore Island. These data provide valuable information for surveillance of P. falciparum infection and for assessing the appropriateness of the current malarial control strategies in the endemic area.

Deca-BDE emissions, validation, and environmental fate in China.

Decabromodiphenyl ether (Deca-BDE) was officially listed in Annex A of the Stockholm Convention for persistent organic pollutants (POPs). It is necessary to establish its emission inventory to help reduce Deca-BDE contamination in the environment. We established a comprehensive Deca-BDE emission inventory in China. The results reveal that, from 2015 to 2017, the Deca-BDE emissions in its production source (source I) were less altered but increased annually in flame retarded plastics processing (source II), Deca-BDE-containing products usage (source III), and electronic waste (e-waste) treatment (source IV). We show that Deca-BDE emissions declined significantly in sources I and II but grew in source III and source IV from 2017 to 2018. We set up the provincial emission inventory to a gridded map on a spatial resolution of 0.25°× 0.25° latitude/longitude. The gridded inventory was incorporated into ChnMETOP model to simulate Deca-BDE concentrations in air and soil, and the modeled concentrations were compared to field-sampling data. The results show that the Deca-BDE emission inventory developed in this study agreed well with observed data, demonstrating that the Deca-BDE inventory in China developed in the present study is reliable. The inventory provides a support for quantifying human exposure risk to Deca-BDE and developing effective mitigation measures to mitigate Deca-BDE emissions.

Air pollution and associated health impact and economic loss embodied in inter-provincial electricity transfer in China.

As the largest producer and consumer of coal in the world, China heavily relies on coal resources for thermal power generation. Owing to the unbalanced distribution of energy resources, electricity transfer among regions in China plays a key role in promoting economic growth and ensuring energy safety. However, little is known about air pollution and the related health impacts resulting from electricity transfer. This study assessed PM2.5 pollution and related health and economic losses attributable to the inter-provincial electricity transfer in mainland China in 2016. The results show that a large amount of virtual air pollutant emissions were transferred from energy-abundant northern, western and central China to well-developed and populated eastern coastal regions. Correspondingly, the inter-provincial electricity transfer dramatically reduced the atmospheric levels of PM2.5 and related health and economic losses in eastern and southern China, while increasing those in northern, western and central China. The health benefits attributable to inter-provincial electricity transfer were mainly found in Guangdong, Liaoning, Jiangsu and Shandong, whereas the extra health loss is concentrated in Hebei, Shanxi, Inner Mongolia, and Heilongjiang. Overall, the inter-provincial electricity transfer led to an extra increase of 3600 (95 % CI: 3200-4100) PM2.5-related deaths and 345 (95 % CI: 294-389) million USD of economic loss in China in 2016. The results could assist air pollution mitigation strategies for the thermal power sector in China by strengthening the cooperation between suppliers and consumers of electricity.

[Semaphorin 6D and Snail are highly expressed in gastric cancer and positively correlated with malignant clinicopathological indexes].

Objective To investigate the expression of semaphorin 6D (SEMA6D) and Snail and their clinicopathological implications in gastric cancer. Methods 54 cases of gastric cancer tissues and 26 paracancerous gastric mucosa were collected for detecting the expression of SEMA6D and Snail by immunohistochemistry and Western blot analysis. The co-localization of SEMA6D and Snail was observed by immunofluorescence double staining and laser scanning confocal microscopy. The correlation between SEMA6D and Snail and their relationships with the clinicopathological features of the patients were analyzed. Results Compared with the paracancerous gastric mucosa, the protein expression of SEMA6D and Snail in the gastric cancer significantly increased, and there was a significant co-localization of SEMA6D and Snail in gastric cancer. Further statistical analysis showed that the expression of SEMA6D and Snail in gastric cancer was positively correlated with the degree of differentiation, invasion, lymph node metastasis and TNM stage. Conclusion The high expression of SEMA6D and Snail in gastric cancer are related to the malignant clinicopathological indexes of gastric cancer.

An unexpected Griess reaction on the important anti-malarial drug primaquine and its application for drug determination.

Primaquine (PMQ), a well-known anti-malarial drug, is of increasing importance as people moving toward global malaria eradication. PMQ has serious side effects that it often causes acute hemolytic toxicity in people with glucose-6-phosphate dehydrogenase (G6PD) deficiency. The development of simple and reliable approaches for quantitative dose monitoring is thus becoming important during malarial treatment with PMQ. Herein, an unexpected Griess reaction on PMQ was systematically studied. The reaction happened between substituted aniline and a primaquine molecule in the presence of nitrite. Both experimental measurements and theoretic calculation showed that UV-vis absorption of the azo products varied because of different electron contributing effects of substituents. Based on the optimized conditions, a novel colorimetric method has been developed for PMQ determination with excellent sensitivity and selectivity. The detection limits for PMQ in water and synthetic urine samples were down to nanomolar range. More importantly, this method has been successfully used to quantify PMQ from human serum samples within clinically relevant concentration ranges.