In Vitro Sensitivity of Plasmodium falciparum Clinical Isolates from the China-Myanmar Border Area to Quinine and Association with Polymorphism in the Na+/H+ Exchanger

Quinine resistance (QNR) in Plasmodium falciparum has been detected in many regions of the world where malaria is endemic. Genetic polymorphisms in at least four genes are implicated in QN susceptibility, and their significance often depends on the genetic background of the parasites. In this study, we have culture-adapted 60 P. falciparum clinical isolates from the China-Myanmar border and assessed their in vitro responses to QN. Our results showed that >50% of the parasite isolates displayed reduced sensitivity to QN, with a half-maximal inhibitory concentration (IC₅₀) above 500 nM. Genotyping of pfcrt found that an overwhelming proportion of the parasite population had the chloroquine-resistant genotype, whereas pfmdr1 mutation genotypes and gene amplification were rare. Genotyping of the P. falciparum Na⁺/H⁺ exchanger gene (pfnhe1) at the minisatellite ms4760 locus identified 10 haplotypes. Haplotype 7, which harbors three copies of the DNNND repeat, was the most predominant, accounting for nearly half of the parasite isolates. Correlation studies did not reveal significant associations of the polymorphisms in pfcrt and pfmdr1 genes with QN response. However, the ms4760 haplotypes were highly associated with in vitro QN responses. In particular, parasite isolates with an increased DNNND copy number tended to have significantly reduced QN susceptibility, whereas parasite isolates with a higher NHNDNHNNDDD copy number had increased QN susceptibility. This study provided further support for the importance of pfnhe1 polymorphisms in influencing QNR in P. falciparum.According to the World Malaria Report 2009, malaria caused an estimated 243 million clinical cases, resulting in nearly 0.9 million deaths, in 2008 (43). While most of the malaria burden is in Africa, it has been estimated that Southeast Asia accounts for 30 and 8% of the global malaria morbidity and mortality, respectively. In the Greater Mekong subregion, malaria epidemiology is characterized by immense geographical heterogeneity in disease distribution with many areas of high endemicity (38). Effective chemotherapy is essential for malaria control, but the emergence and spread of drug resistance in malaria parasites have led to a sharp rise in malaria-related morbidity and mortality (20, 41). This situation is particularly grave in Southeast Asia, where multidrug-resistant (MDR) Plasmodium falciparum poses a major challenge to the control of malaria (39). Therefore, for effective and sustainable malaria management, resistance monitoring and mechanism studies are of high priority, particularly in the era of artemisinin-based combination therapy (42).Quinine (QN) has been a critical antimalarial drug because of its efficacy against chloroquine (CQ)-resistant parasites. In many regions where malaria is endemic, QN is still a primary drug of choice for the treatment of complicated malaria (45). Through its long history in malaria treatment, QN has remained largely effective, and the evolution of QN resistance (QNR) in P. falciparum appears to be slow. However, the observation of reduced sensitivity of P. falciparum to QN in Southeast Asia, South America, and Africa has raised considerable concern (14, 21, 26, 33, 51). In vitro drug assays have found complex patterns of cross-resistance with other quinoline drugs, such as CQ and mefloquine (MQ), suggesting shared resistance mechanisms. Recent genetic and molecular studies indicate that QNR is multifactorial and involves at least four genes: P. falciparum multidrug resistance 1 (pfmdr1), P. falciparum CQ resistance transporter (pfcrt), P. falciparum multidrug resistance-associated protein (pfmrp), and P. falciparum Na⁺/H⁺ exchanger 1 gene (pfnhe1). As its name implies, pfmdr1 is involved in resistance to a number of antimalarials. Global isolates of the parasite show that PfMDR1 harbors a large number of point mutations (11). Genetic studies have found that some PfMDR1 mutations, particularly those that are highly prevalent in South America (S1034C/N1042D/D1246Y), where QN has the longest history of use, are associated with increased QNR (30, 35). In addition, increased copy numbers of pfmdr1 increase resistance not only to MQ (8, 22, 24, 25, 44) but also to other arylamino alcohol drugs, such as QN, halofantrine, and lumefantrine (34). Some mutations in PfCRT, the major CQ resistance (CQR) determinant, are found to be associated with stereo-specific changes in responses to QN and quinidine (6, 10). Recently, a genetic study identified PfMRP as playing a role in the efflux of glutathione, CQ, and QN and contributing to parasite responses to multiple antimalarial drugs (27). In addition to these genes, quantitative trait loci analysis of the Dd2 × HB3 cross further mapped QNR to the pfnhe1 gene, which harbors the minisatellite ms4760 (9). Sequence analysis of laboratory-adapted parasite isolates found that increased copy numbers of the minisatellite repeat (DNNND) are associated with reduced susceptibility to QN (9, 13). Consistent with the role of pfnhe1 in QN response, the Dd2 × HB3 progeny clones with higher levels of QNR also exhibited significantly elevated PfNHE activity (4). Direct evidence of the pfnhe1 involvement in QNR came from transfection studies, where reduced pfnhe1 expression was associated with a significant decrease in QN sensitivity (19). It is noteworthy that the effect of pfnhe1 knockdown is strain specific, providing further support for the complex, multifactorial nature of QNR in P. falciparum. Yet, none of these genes studied so far has accounted for high-level QNR.Southeast Asia has been an epicenter for MDR P. falciparum. Parasites in this region are notorious for their propensity to develop resistance to multiple antimalarial drugs (29). To counter the rapid emergence and spread of drug resistance, malaria drug policies of the countries in Southeast Asia where malaria is endemic have undergone constant changes. CQ and antifolate drugs were abandoned a long time ago (46); resistance to other antimalarial drugs such as MQ has emerged soon after deployment, and QN can no longer be used for malaria monotherapy in this region (17, 26). Although four genes are implicated in reduced QN sensitivity in parasite field isolates, their validity as molecular markers for predicting QNR has been evaluated in only a small number of parasite isolates from diverse regions of the world (13). Therefore, in this study we further investigated the potential association between in vitro QN susceptibility of P. falciparum isolates collected from the China-Myanmar border with genetic polymorphisms in the pfnhe1, pfcrt, and pfmdr1 genes.     

不孕症患者子宫内膜运动功能的研究

目的：探讨不孕症患者子宫内膜运动功能的周期性变化规律。方法：应用经阴道超声对84例不孕症患者的卵泡早期、卵泡中期、卵泡晚期以及黄体早期的子宫内膜运动分别作连续3min检测并录像，再应用计算机媒体播放软件对图像进行放大、快速播放，观测并记录子宫内膜运动的类型、运动频率、运动速度等指标。结果：84例患者336次检测中，显示运动278次（82．74％），无运动51次（15．18％），图像显示不清7次（2．08％）。共检测到7种运动类型。卵泡早期及中期、晚期、黄体早期子宫内膜运动发生率逐渐增高（P〈O．05）。不同时期子宫内膜运动类型的构成比不同，4个时期子宫内膜运动均以Ⅰ型为主，且卵泡早期至黄体早期子宫内膜Ⅰ型运动比例逐渐增加fP〈0.05）。卵泡期Ⅰ型运动传播时间逐渐缩短，黄体早期则显著延长（P〈0．05）。卵泡早期、中期运动频率较卵泡晚期低，卵泡晚期运动频率较黄体早期高（P〈0．05）。结论：子宫内膜运动功能发生周期性变化。经阴道超声及计算机媒体播放软件能直观、有效的检测子宫内膜运动功能。     

Interindividual Differences in Microbial Counts and Biochemical-Associated Variables in the Feces of Healthy Spanish Adults

The aim of this study was to examine, over a period of 1 year, interindividual variations in the most prominent and representative of the cultivatable microbial populations in the feces of eight healthy Spanish persons. A number of biochemical variables (enzyme activities and ammonium and short-chain fatty acid [SCFA] concentrations) thought to be influenced by the GIT microbiota were also analyzed. Total cultivatable microbial counts ranged from 10¹⁰ to 10¹¹ cfu/g of feces. The largest populations were obligate anaerobes belonging to the Clostridiumclusters, followed by species of bifidobacteria and bacteroides. Coliforms and lactobacilli were found at a more intermediate level (10⁵–10⁹ cfu/g). The predominant anaerobe populations remained quite constant over time, but all other microbial groups showed significant interindividual differences. Enzyme profiles were individual-dependent, but within subjects, moderate to high intersample variations over time were recorded for some activities. Fecal ammonium concentration was the most unpredictable variable; this fluctuated widely between individuals and samples. Acetic acid was the most abundant SCFA in the feces, followed by butyric and propionic acids. SCFA concentrations also varied according to the individual; some subjects showed specific profiles in terms of SCFA composition or concentration. The fecal microbial and biochemical parameters studied seemed to be individual-dependent. Most variables were rather stable over time, while others (e.g., ammonium concentration) varied widely.     

NF-κB与细胞凋亡

NF-kB家族及其介导的细胞信号转导通路在细胞凋亡中的作用是国内外研究的热点.研究发现,NF-kB信号转导途径可以通过多种途径抑制细胞凋亡,与IAPs家族、Bcl-2家族、TRAF家族、JNK、FLIP、A20、Gadd45β、MnSOD等有很大关系,但其具体机制尚未完全清楚.通过抑制NF-kB信号转导途径的激活,促进细胞凋亡,可能成为治疗免疫、炎症、肿瘤等疾病的新途径.此外,近年的研究证明NF-kB尚具有促细胞凋亡的作用,并发现NF-kB亚单位的种类及数量在细胞凋亡中起着决定性的作用,为疾病的治疗提供了新的策略.本文就NF-kB与细胞凋亡关系的研究进展作一综述.     

Effects of 6‐meals‐a‐day feeding and 6‐meals‐a‐day feeding combined with adrenalectomy on daily gene expression rhythms in rat epididymal white adipose tissue

The master clock in the hypothalamic suprachiasmatic nucleus (SCN) is assumed to synchronize the tissue‐specific rhythms of the peripheral clocks with the environmental day/night changes via neural, humoral and/or behavioral connections. The feeding rhythm is considered an important Zeitgeber for peripheral clocks, as daytime feeding reverses (clock) gene rhythms in the periphery, but not in the SCN. In this study, we investigated the necessity of a daily feeding rhythm for maintaining gene expression rhythms in epididymal white adipose tissue (eWAT). We showed that 7 of 9 rhythmic metabolic/adipokine genes, but not clock genes, lost their rhythmicity upon exposure to 6‐meals‐a‐day feeding. Previously, we showed comparable effects of adrenalectomy on eWAT; therefore, subsequently we investigated the effect of simultaneous disruption of these humoral and behavioral signaling pathways, by exposing adrenalectomized animals to 6‐meals‐a‐day feeding. Interestingly, under these conditions, all the clock genes and 10 of 11 rhythmic metabolic/adipokine genes lost their rhythmicity. These data indicate that adrenal hormones and feeding rhythm are indispensable for maintaining daily rhythms in metabolic/adipokine gene, but not clock gene, expression in eWAT. In contrast, at least one of these two signals should be present in order for eWAT clock gene rhythms to be maintained.     

诱导型多能干细胞体外向胰岛素分泌细胞分化及对血糖的调控

BACKGROUND:Mouse pluripotent stem cells are induced to differentiate into insulin-secreting cells that can effectively improve blood glucose levels in diabetic mice. OBJECTIVE:To detect mRNA and protein levels of insulin-like cell clusters from induced pluripotent stem cells and to investigate the function of insulin-secreting cells in vitro and in vivo. METHODS:Mouse induced pluripotent stem cells cultured in vitro were induced to differentiate into insulin-secreting cells using combined inducers through three stages. The morphology of endodermal cells, islet-derived progenitor cells and mature islet cells in each stage was observed and relative gene expression levels were detected by PCR. Mature insulin-like cell clusters underwent dithizone staining and functions of insulin released in vitro were observed by ELISA assay. Finally, the insulin-secreting cells were transplanted into the subrenal capsule of diabetic mice, and then blood glucose levels were observed. RESULTS AND CONCLUSION:The mature spherical insulin-like cell clusters were successfully obtained in vitro, which were in iron red by dithizone staining, and expression of insulin mRNA was determined by PCR. The insulin-like cell clusters could secrete insulin in response to various blood glucose levels by ELISA assay. In addition, after the cells clusters were transplanted into the subrenal capsule of mice with type 1 diabetes, the blood glucose levels were marbedly improved.     

Stabilization of asthma prevalence among adolescents and increase among schoolchildren (ISAAC phases I and III) in Spain

BACKGROUND: Most studies show a steep increase in asthma prevalence in the last decades, although few studies had applied the same methodology. Recent reports point out the possibility that the epidemic has come to an end. We have studied the prevalence of asthma in a very large sample of children, repeating the study eight years apart. METHODS: Repeated cross-sectional studies using the International Study of Asthma and Allergies in Childhood (ISAAC) protocol in a sample of Spanish schoolchildren 6-7 (parent-reported) and 13-14 (self-reported) years old in 1994-95 (phase I) and 2002-2003 (phase III). The number of participants was 42 417 in phase I and 42 813 in phase III. The participation rate was over 87% (13-14 years) and 70% (6-7 years). RESULTS: The prevalence of wheezing in the previous year in children aged 13-14 years was 9.0 and 9.3% for boys and 9.6 and 9.2% for girls for phases I and III, respectively. Children 6-7 years of age showed a substantial increase in wheezing in the previous year (7.0 and 10.7% for boys and 5.3 and 8.2% for girls). Other symptoms and severity indexes followed the same patterns. CONCLUSIONS: In the last 8 years, the prevalence of asthma has not changed in 13-14-year-old Spanish children but has increased substantially in 6-7-year olds.     

维稳形式下新疆高校国防生心理健康与觉察压力及应对方式

目的:探讨维稳形势下新疆高校国防生心理健康状况及相关因素。方法:采用SCL-90症状自评量表、觉察压力量表(PSS-C)和简易应对方式问卷(SCSQ)进行测验。结果:1维稳形势下,国防生觉察压力、应对方式在年级、性别和灾难经历上具有显著差异(P0.01),SCL-90得分与大学生常模相比,除强迫症状和偏执外,其余各因子分和SCL-90总均分显著低于大学生常模(t=-2.14,-2.10,-2.82,-2.49,-2.30,-2.91,-2.71,-2.34;P0.01);2预测感与强迫症状、人际敏感和抑郁呈显著正相关(P0.01);控制感、超载感与躯体化、抑郁、焦虑、敌对、恐怖、精神病性和SCL-90总均分呈显著负相关(P0.01);除人际敏感外,积极应对方式与SCL-90各因子及总均分呈显著负相关(P0.01)。3预测感、超载感和积极应对方式对心理健康有直接效应(路径系数为0.20、-0.22和0.17),控制感对心理健康的间接效应为0.044。结论:觉察压力和积极应对方式是影响维稳形势下新疆高校国防生心理健康的两个重要因素;积极应对方式在控制感和心理健康状况间具有中介作用。