In Vitro Activities of Quinine and Other Antimalarials and pfnhe Polymorphisms in Plasmodium Isolates from Kenya

Resistance to the amino alcohol quinine has been associated with polymorphisms in pfnhe, a sodium hydrogen exchanger. We investigated the role of this gene in quinine resistance in vitro in isolates from Kenya. We analyzed pfnhe whole-gene polymorphisms, using capillary sequencing, and pfcrt at codon 76 (pfcrt-76) and pfmdr1 at codon 86 (pfmdr1-86), using PCR-enzyme restriction methodology, in 29 isolates from Kilifi, Kenya, for association with the in vitro activities of quinine and 2 amino alcohols, mefloquine and halofantrine. In vitro activity was assessed as the drug concentration that inhibits 50% of parasite growth (IC₅₀). The median IC₅₀s of quinine, halofantrine, and mefloquine were 92, 22, and 18 nM, respectively. The presence of 2 DNNND repeats in microsatellite ms4760 of pfnhe was associated with reduced susceptibility to quinine (60 versus 227 nM for 1 and 2 repeats, respectively; P < 0.05), while 3 repeats were associated with restoration of susceptibility. The decrease in susceptibility conferred by the 2 DNNND repeats was more pronounced in parasites harboring the pfmdr1-86 mutation. No association was found between susceptibility to quinine and the pfcrt-76 mutation or between susceptibility to mefloquine or halofantrine and the pfnhe gene and the pfcrt-76 and pfmdr1-86 mutations. Using previously published data on the in vitro activities of chloroquine, lumefantrine, piperaquine, and dihydroartemisinin, we investigated the association of their activities with pfnhe polymorphism. With the exception of a modulation of the activity of lumefantrine by a mutation at position 1437, pfnhe did not modulate their activities. Two DNNND repeats combined with the pfmdr1-86 mutation could be used as an indicator of reduced susceptibility to quinine.The amino alcohol quinine (QN) remains one of the important drugs against malaria. It is the drug of choice for the treatment of severe malaria, and in most African countries, including Kenya, where artemisinin-based combinations (lumefantrine-artemether, amodiaquine-artesunate) are now first-line treatments, 7-day quinine monotherapy has become the second-line treatment for uncomplicated malaria (44). However, there is evidence of selection and spread of QN-resistant parasites or those with reduced susceptibility to QN (1-3, 8, 30, 34). This observation led to the investigation of artesunate (an artemisinin derivative) as an alternative to QN for the treatment of severe malaria (14). However, this option could now be compromised by the emergence of artemisinin resistance (9).Several studies have been dedicated to understanding the mechanisms of quinine resistance. Polymorphisms in pfmdr, a gene associated with chloroquine (CQ) resistance, modulate QN susceptibility (27, 33, 36). A mutation of the CQ resistance gene pfcrt at codon 76 (pfcrt-76) has been associated with reduced susceptibility to QN in vitro, although transfection studies have shown conflicting results (16, 37). A seminal study on the association of polymorphisms in pfnhe, a sodium hydrogen exchanger gene, and the in vitro activity of QN indicated that an increase in the number of DNNND repeats (1-5) in an ms4760 microsatellite was associated with reduced susceptibility to QN (10), and this finding was confirmed recently (13). Variations in the copy number of this repeat in isolates from areas where QN efficacy is known to be reduced in vivo have also been reported (41).The initial discovery that the microsatellite ms4760 region was associated with modulation of QN activity was based on the sequencing of the pfnhe gene of reference strains (71 in total) from several areas where malaria is endemic, including Kenya (10). However, the number of strains from each site of malaria endemicity was relatively small; for instance, only 3 strains from Kenya were analyzed. Subsequent investigations on the role of this gene in QN resistance focused on analysis of only the ms4760 region (13, 41), and additional genetic variations of Plasmodium falciparum in local populations may have been overlooked.With this in mind, we sequenced the whole pfnhe gene of 29 isolates from Kilifi, on the Kenyan coast, and analyzed this gene polymorphism in association with QN activity in vitro, along with the activities of the amino alcohols mefloquine (MFQ) and halofantrine (HLF). Isolates we analyzed in the current study were used in a previous study to investigate polymorphisms of pfcrt at pfcrt-76 and pfmdr1 at codon 86 (pfmdr1-86) for associations with the in vitro activities of CQ, the amino alcohol lumefantrine (LM), and the drugs piperaquine (PQ) and dihydroartemisinin (DHA) (19). We included part of these data to establish the impact of pfnhe polymorphism on the in vitro activities of the aforementioned drugs and the roles of the pfcrt-76 and pfmdr1-86 genotypes on QN activity in vitro.     

Health profile of deaf Canadians: analysis of the Canada Community Health Survey

OBJECTIVE

To profile the health of deaf and hard-of-hearing Canadians inrelation to the population as a whole.

DESIGN

Using data from the Canada Community Health Survey 1.1, across-sectional survey conducted by Statistics Canada with a total of 131 535 respondents, a series of logistic regression models was fitted to estimate the odds, compared with the general population, of respondents classified as having hearing problems reporting the presence of various chronic health outcomes; of their utilizing the health care system; of their engaging in certain health promotion activities; and of their reporting certain perceptions about their overall health. For each odds ratio, 95% confidence intervals are provided. All analyses were adjusted for age and sex with some analyses being restricted to appropriate age ranges or having further adjustments made, depending on the outcomes.

MAIN OUTCOME MEASURES

In addition to indications of deafness or hearing loss, this study examined health care utilization, several commonly accepted health outcomes, engagement in health promotion activities, and perceptions of overall health.

RESULTS

Approximately 4% of respondents in the cross-sectional survey were considered to have hearing problems. The prevalence of hearing problems increased withage, with males having a slightly higher prevalence of hearing problems compared with females (4.52% versus 3.53%). Respondents classified as having hearing problems, whether hearing loss or deafness, were more likely to report adverse health conditions and low levels of physical activity, and to experience higher rates of depression. Respondents classified as having hearing problems were not more likely to smoke or to drink excessively.

CONCLUSION

Communication is essential to both health promotion and health care delivery. Deafness—both the disability and the culture—creates barriers to communication. Individual practitioners can and should consider the communication needs of individual patients with hearing loss or deafness to avoid barriers to optimal health.     

Patterns of apoptosis during degeneration of the pronephros and mesonephros.

PURPOSE: The adult mammalian kidney is preceded developmentally by 2 primitive kidneys. We determine whether apoptosis is involved in the regression of these primitive organs and document its temporospatial characteristics. MATERIALS AND METHODS: Timed pregnant rats were sacrificed at 11 to 16 days of gestation inclusively. The fetuses were histologically examined to determine the timing and pattern of apoptosis in the primitive kidneys, including pronephros and mesonephros. RESULTS: Apoptosis of the pronephros occurred primarily at 12 days of gestation. Apoptosis of the distal mesonephros occurred primarily at 13 days and was completed by 14, which left the proximal mesonephros a functioning kidney during the early period of development. The location and timing of apoptosis were consistent and specific. CONCLUSIONS: Apoptosis appears to be an important mechanism of the normal regression of the primitive kidney and follows a strict temporospatial pattern.     

Gender and PTSD: What can we learn from female police officers?

Studies of civilians typically find that female gender is a risk factor for posttraumatic stress disorder (PTSD). Police and military studies often find no gender differences in PTSD. We compared 157 female police officers and 124 female civilians on several variables including trauma exposure, peritraumatic emotional distress, current somatization, and cumulative PTSD symptoms. We found that despite greater exposure to assaultive violence in the officer group, female civilians reported significantly more severe PTSD symptoms. Elevated PTSD symptoms in female civilians were explained by significantly more intense peritraumatic emotional distress among female civilians. We also found that female officers showed a stronger direct relationship between peritraumatic emotional distress and current somatization. Our findings suggest that apparent gender differences in PTSD may result from differences in peritraumatic emotionality, which influence subsequent PTSD and somatization symptoms. Emotionality may be more important than biological sex in understanding gender differences in PTSD.     

Enhancing Medication Adherence Among Inner-City Children with Asthma: Results from Pilot Studies

Purpose: This study was designed to test the hypothesis that fetal exposure to corticosteroids in the antenatal period is an independent risk factor for the development of asthma in childhood. Methods: A population-based cohort study was conducted of all pregnant women who resided in Nova Scotia, Canada, and gave birth to a singleton fetus between January 1989 and December 1998 and lived to discharge. After exclusions, 79,395 infants were available for analysis. Using linked health care utilization records, incident asthma cases between 36 to 72 months of age were identified. Generalized Estimating Equations were used to estimate the odds ratio of the association between exposure to corticosteroids and asthma while controlling for confounders. Results: Over the 10 years of the study corticosteroid therapy increased by threefold. Exposure to corticosteroids during pregnancy was associated with a risk of asthma in childhood: adjusted odds ratio of 1.23 (95% confidence interval: 1.06, 1.44). Conclusions: Antenatal steroid therapy appears to be an independent risk factor for the development of asthma between 36 and 72 months of age. Further research into the smallest possible steroid dose required to achieve the desired post-natal effect is needed to reduce the risk of developing childhood asthma.