Disseminated intravascular coagulation phenotype is regulated by the TRPM7 channel during sepsis.

BACKGROUND: Sepsis is an uncontrolled inflammatory response against a systemic infection that results in elevated mortality, mainly induced by bacterial products known as endotoxins, producing endotoxemia. Disseminated intravascular coagulation (DIC) is frequently observed in septic patients and is associated with organ failure and death. Sepsis activates endothelial cells (ECs), promoting a prothrombotic phenotype contributing to DIC. Ion channel-mediated calcium permeability participates in coagulation. The transient reception potential melastatin 7 (TRPM7) non-selective divalent cation channel that also contains an α-kinase domain, which is permeable to divalent cations including Ca2+, regulates endotoxin-stimulated calcium permeability in ECs and is associated with increased mortality in septic patients. However, whether endothelial TRPM7 mediates endotoxemia-induced coagulation is not known. Therefore, our aim was to examine if TRPM7 mediates coagulation during endotoxemia. RESULTS: The results showed that TRPM7 regulated endotoxin-induced platelet and neutrophil adhesion to ECs, dependent on the TRPM7 ion channel activity and by the α-kinase function. Endotoxic animals showed that TRPM7 mediated neutrophil rolling on blood vessels and intravascular coagulation. TRPM7 mediated the increased expression of the adhesion proteins, von Willebrand factor (vWF), intercellular adhesion molecule 1 (ICAM-1), and P-selectin, which were also mediated by the TRPM7 α-kinase function. Notably, endotoxin-induced expression of vWF, ICAM-1 and P-selectin were required for endotoxin-induced platelet and neutrophil adhesion to ECs. Endotoxemic rats showed increased endothelial TRPM7 expression associated with a procoagulant phenotype, liver and kidney dysfunction, increased death events and an increased relative risk of death. Interestingly, circulating ECs (CECs) from septic shock patients (SSPs) showed increased TRPM7 expression associated with increased DIC scores and decreased survival times. Additionally, SSPs with a high expression of TRPM7 in CECs showed increased mortality and relative risk of death. Notably, CECs from SSPs showed significant results from the AUROC analyses for predicting mortality in SSPs that were better than the Acute Physiology and Chronic Health Evaluation II (APACHE II) and the Sequential Organ Failure Assessment (SOFA) scores. CONCLUSIONS: Our study demonstrates that sepsis-induced DIC is mediated by TRPM7 in ECs. TRPM7 ion channel activity and α-kinase function are required by DIC-mediated sepsis-induced organ dysfunction and its expression are associated with increased mortality during sepsis. TRPM7 appears as a new prognostic biomarker to predict mortality associated to DIC in SSPs, and as a novel target for drug development against DIC during infectious inflammatory diseases.

A randomized controlled trial of two dialysate sodium concentrations in hospitalized hemodialysis patients.

BACKGROUND: Several large dialysis organizations have lowered the dialysate sodium concentration (DNa) in an effort to ameliorate hypervolemia. The implications of lower DNa on intra-dialytic hypotension (IDH) during hospitalizations of hemodialysis (HD) patients is unclear. METHODS: In this double-blind, single center, randomized controlled trial (RCT), hospitalized maintenance HD patients were randomized to receive higher (142 mmol/L) or lower (138 mmol/L) DNa for up to six sessions. Blood pressure (BP) was measured in a standardized fashion pre-HD, post-HD and every 15 min during HD. The endpoints were: (i) the average decline in systolic BP (pre-HD minus lowest intra-HD, primary endpoint) and (ii) the proportion of total sessions complicated by IDH (drop of ≥20 mmHg from the pre-HD systolic BP, secondary endpoint). RESULTS: A total of 139 patients completed the trial, contributing 311 study visits. There were no significant differences in the average systolic blood pressure (SBP) decline between the higher and lower DNa groups (23 ± 16 versus 26 ± 16 mmHg; P = 0.57). The proportion of total sessions complicated by IDH was similar in the higher DNa group, compared with the lower DNa group [54% versus 59%; odds ratio 0.72; 95% confidence interval (95% CI) 0.36-1.44; P = 0.35]. In post hoc analyses adjusting for imbalances in baseline characteristics, higher DNa was associated with 8 mmHg (95% CI 2-13 mmHg) less decline in SBP, compared with lower DNa. Patient symptoms and adverse events were similar between the groups. CONCLUSIONS: In this RCT for hospitalized maintenance of HD patients, we found no difference in the absolute SBP decline between those who received higher versus lower DNa in intention-to-treat analyses. Post hoc adjusted analyses suggested a lower risk of IDH with higher DNa; thus, larger, multi-center studies to confirm these findings are warranted.

Multiple Plasmodium falciparum drug resistance polymorphisms identified in a pregnant woman with severe malaria and a concomitant spontaneous abortion in Cross River, Nigeria, West Africa.

BACKGROUND: The development of resistance by Plasmodium falciparum to anti-malarial drugs impedes any benefits of the drug. In addition, absence or delayed availability of current anti-malarial drugs in remote areas has the potential to results to parasite escape and continuous transmission. CASE PRESENTATION: The case of a 29-year old pregnant woman from Biase Local Government Area in Cross River State Nigeria presenting with febrile illness and high body temperature of 38.7 °C was reported. She looked pale and vomited twice on arrival at the health facility. Her blood smear on the first day of hospitalization was positive for P. falciparum by RDT, microscopy (21,960 parasite/µl) and real-time PCR, with a PCV of 18%. She was treated with 600 mg intravenous quinine in 500 ml of 5% Dextrose/0.9% Saline 8-hourly for 24 h. On the second day of hospitalization, she complained of weakness, persistent high-grade fever and vaginal bleeding. A bulging amnion from an extended cervix was observed. Following venous blood collection for laboratory investigations, 600 µg of misoprostol was inserted into the posterior fornix of her vagina as part of her obstetric care. Parenteral quinine was discontinued, and she was given full therapeutic regimen of artemether-lumefantrine 80/480 mg tablets to be taken for 3 days beginning from the second day. Her blood samples on the second and third day of hospitalization remained positive for P. falciparum by all three diagnostic methods. Single nucleotide polymorphism (SNP) assay on all three P. falciparum isolates revealed the presence of variants associated with multiple drug resistant markers. DISCUSSION: Infecting P. falciparum isolates may have been resistant to initial quinine treatment resulting from parasite cross-resistance with other quinoline associated resistant markers such as 86Y and 184 F. CONCLUSIONS: Therefore, the likely transmission of similarly resistant parasites in the study area calls for reinforcement of interventions and adherence to current World Health Organization guidelines in administering only approved drugs to individuals in order to mitigate parasite escape and eventual transmission to other susceptible individuals.

Specific Electrocardiograph Intervals Predict Hospitalization with Atrial Fibrillation in Those with Chronic Kidney Disease.

INTRODUCTION: Atrial fibrillation (AF) is common in patients with chronic kidney disease (CKD) and is associated with higher rates of hospitalization compared to those without AF. Whether routine electrocardiographic parameters are predictive of future hospitalizations with AF is not clear. METHODS: The present study is an analysis of a prospective cohort of 2,759 patients without baseline AF from the Chronic Renal Insufficiency Cohort, a large prospective multicenter study of patients with nondialysis-dependent CKD. Unadjusted and adjusted Cox regression models were fit to examine the association of baseline categories of QTc, QRS, and PR intervals with time to first hospitalization with AF. Restricted cubic splines were used to display nonlinear associ-ations. RESULTS: The mean age of subjects at baseline was 58 ± 11 years, 55% were male, and 44% were Black. The mean follow-up was 6.6 years during which 224 participants experienced a hospitalization with AF. The association of baseline QTc interval with risk of AF hospitalization was nonlinear, such that the lowest and highest quartiles of QTc (<407 and >431 ms, respectively) had higher adjusted risk of AF hospitalization, compared with the second quartile (407-416 ms) (aHR Q1:Q2 1.58, 95% CI 1.03-2.41; p = 0.03; aHR Q4:Q2 1.84, 95% CI 1.22-2.78; p < 0.01). Longer QRS was associated with a higher risk of hospitalization with AF among the subgroup of patients with a history of heart failure (HF). PR interval was not associated with AF hospitalization. DISCUSSION/CONCLUSION: The association of QTc with risk for hospitalization with AF among patients with CKD is nonlinear, while the association of longer QRS with AF hospitalization is restricted to patients with baseline HF. Electrocardiography may represent a simple and widely accessible method for risk stratification of future AF in patients with CKD.

Antibody responses to a suite of novel serological markers for malaria surveillance demonstrate strong correlation with clinical and parasitological infection across seasons and transmission settings in The Gambia.

BACKGROUND: As malaria transmission declines, sensitive diagnostics are needed to evaluate interventions and monitor transmission. Serological assays measuring malaria antibody responses offer a cost-effective detection method to supplement existing surveillance tools. METHODS: A prospective cohort study was conducted from 2013 to 2015 in 12 villages across five administrative regions in The Gambia. Serological analysis included samples from the West Coast Region at the start and end of the season (July and December 2013) and from the Upper River Region in July and December 2013 and April and December 2014. Antigen-specific antibody responses to eight Plasmodium falciparum (P. falciparum) antigens-Etramp5.Ag1, GEXP18, HSP40.Ag1, Rh2.2030, EBA175 RIII-V, PfMSP119, PfAMA1, and PfGLURP.R2-were quantified using a multiplexed bead-based assay. The association between antibody responses and clinical and parasitological endpoints was estimated at the individual, household, and population level. RESULTS: Strong associations were observed between clinical malaria and concurrent sero-positivity to Etramp5.Ag1 (aOR 4.60 95% CI 2.98-7.12), PfMSP119 (aOR 4.09 95% CI 2.60-6.44), PfAMA1 (aOR 2.32 95% CI 1.40-3.85), and PfGLURP.R2 (aOR 3.12, 95% CI 2.92-4.95), while asymptomatic infection was associated with sero-positivity to all antigens. Village-level sero-prevalence amongst children 2-10 years against Etramp5.Ag1, HSP40.Ag1, and PfMSP119 showed the highest correlations with clinical and P. falciparum infection incidence rates. For all antigens, there were increased odds of asymptomatic P. falciparum infection in subjects residing in a compound with greater than 50% sero-prevalence, with a 2- to 3-fold increase in odds of infection associated with Etramp5.Ag1, GEXP18, Rh2.2030, PfMSP119, and PfAMA1. For individuals residing in sero-positive compounds, the odds of clinical malaria were reduced, suggesting a protective effect. CONCLUSIONS: At low transmission, long-lived antibody responses could indicate foci of malaria transmission that have been ongoing for several seasons or years. In settings where sub-patent infections are prevalent and fluctuate below the detection limit of polymerase chain reaction (PCR), the presence of short-lived antibodies may indicate recent infectivity, particularly in the dry season when clinical cases are rare. Serological responses may reflect a persistent reservoir of infection, warranting community-targeted interventions if individuals are not clinically apparent but have the potential to transmit. Therefore, serological surveillance at the individual and household level may be used to target interventions where there are foci of asymptomatically infected individuals, such as by measuring the magnitude of age-stratified antibody levels or identifying areas with clustering of above-average antibody responses across a diverse range of serological markers.

Sero-epidemiological evaluation of malaria transmission in The Gambia before and after mass drug administration.

BACKGROUND: As The Gambia aims to achieve malaria elimination by 2030, serological assays are a useful surveillance tool to monitor trends in malaria incidence and evaluate community-based interventions. METHODS: Within a mass drug administration (MDA) study in The Gambia, where reduced malaria infection and clinical disease were observed after the intervention, a serological sub-study was conducted in four study villages. Spatio-temporal variation in transmission was measured with a panel of recombinant Pf antigens on a multiplexed bead-based assay. Village-level antibody levels were quantified as under-15 sero-prevalence, sero-conversion rates, and age-adjusted antibody acquisition rates. Antibody levels prior to MDA were assessed for association with persistent malaria infection after community chemoprophylaxis. RESULTS: Seasonal changes in antibodies to Etramp5.Ag1 were observed in children under 15 years in two transmission settings-the West Coast and Upper River Regions (4.32% and 31.30% Pf prevalence, respectively). At the end of the malaria season, short-lived antibody responses to Etramp5.Ag1, GEXP18, HSP40.Ag1, EBA175 RIII-V, and Rh2.2030 were lower amongst 1-15 year olds in the West Coast compared to the Upper River, reflecting known differences in transmission. Prior to MDA, individuals in the top 50th percentile of antibody levels had two-fold higher odds of clinical malaria during the transmission season, consistent with previous findings from the Malaria Transmission Dynamics Study, where individuals infected before the implementation of MDA had two-fold higher odds of re-infection post-MDA. CONCLUSIONS: Serological markers can serve dual functions as indicators of malaria exposure and incidence. By monitoring age-specific sero-prevalence, the magnitude of age-stratified antibody levels, or identifying groups of individuals with above-average antibody responses, these antigens have the potential to complement conventional malaria surveillance tools. Further studies, particularly cluster randomised trials, can help establish standardised serological protocols to reliably measure transmission across endemic settings.

Predictors of Intradialytic Symptoms: An Analysis of Data From the Hemodialysis Study.

BACKGROUND: Most patients receiving maintenance hemodialysis (HD) experience adverse symptoms, which are associated with decreased quality of life. Despite decades of experience, our understanding of causes of HD symptoms remains limited. We aimed to identify modifiable patient- and HD-related predictors of intradialytic symptoms. STUDY DESIGN: Prospective cohort. SETTING & PARTICIPANTS: We leveraged patient-level (n=1,838) and HD session-level (n=64,797) data from the Hemodialysis Trial. EXPOSURE: Pre-HD serum urea nitrogen (SUN) level, pre-HD systolic blood pressure (SBP), intradialytic SBP decline, and ultrafiltration rate (UFR). OUTCOMES: Intra-HD symptoms, including cramps, nausea, chest pain, headache, and lightheadedness. ANALYTICAL APPROACH: Random-effects logistic regression models. RESULTS: Overall, symptoms occurred in 10.7% of HD sessions. Higher pre-HD SUN level (per 10 mg/dL) was associated with higher adjusted odds of muscle cramping and lightheadedness (adjusted ORs [aORs] of 1.20 [95% CI, 1.17-1.22] and 1.13 [95% CI, 1.08-1.18], respectively). SBP decline (from the predialysis value to the dialysis session nadir, per each 10-mm Hg decrease) was associated with greater risk for muscle cramping, headache, chest pain, vomiting, and lightheadedness (the largest aORs were for the 2 latter symptoms: 1.24 [95% CI, 1.20-1.28] and 1.37 [95% CI, 1.33-1.42], respectively). Higher UFR (per 1 mL/kg/h) was associated with greater odds of cramping (aOR, 1.03; 95% CI, 1.02-1.03). Conversely, higher pre-HD SBP (per 10 mm Hg) was associated with reduced risk for vomiting (aOR, 0.88; 95% CI, 0.85-0.92) and lightheadedness (aOR, 0.82; 95% CI, 0.80-0.85). LIMITATIONS: Measured osmolality, dialysate prescription data, and time stamps for symptom occurrence were not available. Clinical trial data may not be broadly generalizable. CONCLUSIONS: Higher pre-HD SUN level, UFR, pre-HD SBP, and SBP decline are independently associated with different patterns of adverse intradialytic symptoms. Recognition that different symptoms may have variable causes may allow tailoring of personalized treatments in future interventional studies.

Myeloperoxidase and the Risk of CKD Progression, Cardiovascular Disease, and Death in the Chronic Renal Insufficiency Cohort (CRIC) Study.

BACKGROUND: Myeloperoxidase (MPO) catalyzes the formation of reactive nitrogen species and levels are elevated in patients with chronic kidney disease (CKD). Although increased oxidative stress and inflammation are associated with progression of CKD and cardiovascular disease (CVD), relationships between MPO concentration, CKD progression, CVD, and death remain unclear. STUDY DESIGN: Prospective cohort. SETTING & PARTICIPANTS: 3,872 participants from the Chronic Renal Insufficiency Cohort (CRIC) who had MPO measured at baseline. EXPOSURE: Baseline MPO concentration. OUTCOMES: CKD progression (kidney transplantation, dialysis initiation, or 50% decline in baseline estimated glomerular filtration rate [eGFR] and eGFR≤15mL/min/1.73m2), CVD (heart failure, myocardial infarction, or stroke), and death. ANALYTICAL APPROACH: Cox proportional hazards models. RESULTS: In adjusted analyses, higher MPO level (per 1-SD increase in log-transformed MPO) was associated with 10% higher risk for CKD progression (adjusted HR, 1.10; 95% CI, 1.01-1.19; P=0.03), 12% higher risk for CVD (adjusted HR, 1.12; 95% CI, 1.03-1.22; P<0.01), and 13% increased risk for death (adjusted HR, 1.13; 95% CI, 1.04-1.22; P<0.01). There was evidence for effect modification of the association of MPO level with CKD progression by baseline eGFR (P interaction=0.02), but not for CVD (P interaction=0.2) or death (P interaction=0.1). In stratified analyses, MPO level (per 1-SD increase in log-transformed MPO) was associated with greater risk for CKD progression among participants with eGFR>45mL/min/1.73m2 (adjusted HR, 1.23; 95% CI, 1.03-1.46; P=0.02) compared with those with eGFR≤45mL/min/1.73m2 (adjusted HR, 1.10; 95% CI, 1.02-1.20; P=0.02). The association of MPO level with CVD and death was no longer significant after adjustment for cardiac biomarkers. LIMITATIONS: Potential residual confounding, lack of repeated measurements of MPO. CONCLUSIONS: Higher MPO level was associated with increased risk for CKD progression, but not with CVD and death in patients with CKD from CRIC. Whether therapies aimed at reducing MPO activity can result in improved clinical outcomes is yet to be determined.

Efficacy and safety of more potent antiplatelet therapy with vorapaxar in patients with impaired renal function.

Patients with renal disease are often undertreated with antiplatelet therapy due to concerns about bleeding. Vorapaxar blocks platelet activation via the PAR-1 receptor and reduces cardiovascular events in patients with stable atherosclerosis, but with increased bleeding. We examined the efficacy and safety of vorapaxar in patients with impaired renal function. TRA2°P-TIMI 50 randomized patients with stable atherosclerosis to vorapaxar or. We analyzed patients with eGFR assessed who qualified with a history of MI or PAD (without stroke or TIA) (n = 19,932). Cox models assessed the risk of CV events and bleeding by quartile of baseline eGFR in the placebo arm and then by randomized assignment. Net clinical outcome (NCO) was predefined as CV death, MI, stroke, or GUSTO severe bleeding. Patients with lower eGFR tended to be older, female, have hypertension, hyperlipidemia or prior PAD. In the placebo arm, baseline eGFR in the lowest quartile was associated with a 26% higher risk of CV death, MI or stroke (Q1:Q4 HRadj 1.26, 1.03-1.55) and 73% higher risk of GUSTO moderate or severe bleeding (HRadj 1.73, 1.12-2.65). Vorapaxar reduced the risk of MACE to a similar extent (14-26%) across quartiles of baseline eGFR (P interaction = 0.70) and increased the relative risk of GUSTO moderate or severe bleeding (P interaction = 0.54). NCO was similar across quartiles of eGFR (P interaction = 0.65). Intensification of antiplatelet therapy with vorapaxar offers comparable net clinical benefit regardless of baseline renal function. These data support the use of more potent antiplatelet regimens in patients with renal dysfunction.

Plasmodium Infection Is Associated with Impaired Hepatic Dimethylarginine Dimethylaminohydrolase Activity and Disruption of Nitric Oxide Synthase Inhibitor/Substrate Homeostasis.

Inhibition of nitric oxide (NO) signaling may contribute to pathological activation of the vascular endothelium during severe malaria infection. Dimethylarginine dimethylaminohydrolase (DDAH) regulates endothelial NO synthesis by maintaining homeostasis between asymmetric dimethylarginine (ADMA), an endogenous NO synthase (NOS) inhibitor, and arginine, the NOS substrate. We carried out a community-based case-control study of Gambian children to determine whether ADMA and arginine homeostasis is disrupted during severe or uncomplicated malaria infections. Circulating plasma levels of ADMA and arginine were determined at initial presentation and 28 days later. Plasma ADMA/arginine ratios were elevated in children with acute severe malaria compared to 28-day follow-up values and compared to children with uncomplicated malaria or healthy children (p<0.0001 for each comparison). To test the hypothesis that DDAH1 is inactivated during Plasmodium infection, we examined DDAH1 in a mouse model of severe malaria. Plasmodium berghei ANKA infection inactivated hepatic DDAH1 via a post-transcriptional mechanism as evidenced by stable mRNA transcript number, decreased DDAH1 protein concentration, decreased enzyme activity, elevated tissue ADMA, elevated ADMA/arginine ratio in plasma, and decreased whole blood nitrite concentration. Loss of hepatic DDAH1 activity and disruption of ADMA/arginine homeostasis may contribute to severe malaria pathogenesis by inhibiting NO synthesis.

Efficacy of indoor residual spraying with dichlorodiphenyltrichloroethane against malaria in Gambian communities with high usage of long-lasting insecticidal mosquito nets: a cluster-randomised controlled trial.

BACKGROUND: Although many malaria control programmes in sub-Saharan Africa use indoor residual spraying with long-lasting insecticidal nets (LLINs), the two studies assessing the benefit of the combination of these two interventions gave conflicting results. We aimed to assess whether the addition of indoor residual spraying to LLINs provided a significantly different level of protection against clinical malaria in children or against house entry by vector mosquitoes. METHODS: In this two-arm cluster, randomised, controlled efficacy trial we randomly allocated clusters of Gambian villages using a computerised algorithm to LLINs alone (n=35) or indoor residual spraying with dichlorodiphenyltrichloroethane plus LLINs (n=35). In each cluster, 65-213 children, aged 6 months to 14 years, were surveyed at the start of the 2010 transmission season and followed in 2010 and 2011 by passive case detection for clinical malaria. Exposure to parasite transmission was assessed by collection of vector mosquitoes with both light and exit traps indoors. Primary endpoints were the incidence of clinical malaria assessed by passive case detection and number of Anopheles gambiae sensu lato mosquitoes collected per light trap per night. Intervention teams had no role in data collection and the data collection teams were not informed of the spray status of villages. The trial is registered at the ISRCTN registry, number ISRCTN01738840. FINDINGS: LLIN coverage in 2011 was 3510 (93%) of 3777 children in the indoor residual spraying plus LLIN group and 3622 (95.5%) of 3791 in the LLIN group. In 2010, 7845 children were enrolled, 7829 completed passive case detection, and 7697 (98%) had complete clinical and covariate data. In 2011, 7009 children remained in the study, 648 more were enrolled, 7657 completed passive case detection, and 7545 (98.5%) had complete data. Indoor residual spraying coverage per cluster was more than 80% for both years in the indoor residual spraying plus LLIN group. Incidence of clinical malaria was 0.047 per child-month at risk in the LLIN group and 0.044 per child-month at risk in the indoor residual spraying plus LLIN group in 2010, and 0.032 per child-month at risk in the LLIN group and 0.034 per child-month at risk in the indoor residual spraying plus LLIN group in 2011. The incident rate ratio was 1.08 (95% CI 0.80-1.46) controlling for confounders and cluster by mixed-effect negative binomial regression on all malaria attacks for both years. No significant difference was recorded in the density of vector mosquitoes caught in light traps in houses over the two transmission seasons; the mean number of A gambiae sensu lato mosquitoes per trap per night was 6.7 (4.0-10.1) in the LLIN group and 4.5 (2.4-7.4) in the indoor residual spraying plus LLIN group (p=0.281 in the random-effects linear regression model). INTERPRETATION: We identified no significant difference in clinical malaria or vector density between study groups. In this area with high LLIN coverage, moderate seasonal transmission, and susceptible vectors, indoor residual spraying did not provide additional benefit. FUNDING: UK Medical Research Council.

Phosphorylation at the N-terminal finger subdomain of a viral RNA-dependent RNA polymerase.

The RNA-dependent RNA polymerase (RdRP) of the Hepatitis C virus (HCV), named NS5B, is phosphorylated by the cellular protein kinase C-related kinase 2 (PRK2) at two serine residues (Ser29 and Ser42) of the finger subdomain (genotype 1b). Herein, using bioinformatics, we selected four potential phosphorylation residues (Ser46, Ser76, Ser96 and Ser112) of NS5B (genotype 2a) for study. Whereas the NS5B Ser46D and Ser76D substitutions seemed to improve polymerase activity, the Ser96D mutation decreased colony formation efficiency. Active WT NS5B was utilized in in vitro kinase assays, and phosphopeptides were analyzed by mass spectrometry. Interestingly, the data indicated that both the NS5B Ser29 and Ser76 residues resulted phosphorylated. Thus, as Ser76 is absolutely conserved across HCV genotypes, our results confirmed the relevance of these sites for both genotypes and suggested that Ser76 becomes phosphorylated by a cellular kinase different from PRK2. By molecular dynamic simulations, we show that new interactions between space-adjacent amino acid chains could be established by the presence of a di-anionic phosphate group on the analyzed serines to possibly modify RNA polymerase activity. Together, our data present novel evidence on the complex regulation at the finger subdomain of HCV NS5B via phosphorylation.

A comparative case control study of the determinants of clinical malaria in The Gambia.

BACKGROUND: The massive deployment of life saving malaria interventions has not only resulted in a decline in disease burden but a change in the risk of infection and disease. The study reassesses the importance of known risk factors and reviews demographic and socio-economic determinants of malaria risk in the population. METHODS: This was a case-control study involving 150 children with test-confirmed malaria infection recruited from the outpatient clinics of three health facilities (cases) in the Greater Banjul area, The Gambia. One hundred and fifty controls, negative for malaria were matched on age, residence. Information was collected from respondents on the use of long lasting insecticidal nets, occupation, housing structure, knowledge of malaria and socio-demographic factors. RESULTS: The mean age of study participants was 6.8 (SD 3.3) years with 147 (49%) being males. Significant determinants of malaria risk were parent's occupation: mother as trader (OR 0.18, 95% CI 0.04 - 0.73, p = 0.017), father as trader (OR 0.02, 95% CI 0.002- 0.193, p = 0.001), civil servants (OR 0.04, 95% CI 0.008- 0.257, p =0.001) or handyman (OR 0.03, 95% CI 0.005- 0.182, p < 0.001). Children sleeping in rooms with windowpanes had a 76% reduction in their odds of malaria (OR 0.24, 95%CI 0.07- 0.82, p = 0.022. CONCLUSION: Household socio-economic status plays an important role in management of illnesses. The ability of mothers to engage in an occupation increases household resources to access healthcare and on time. The balance between the type of mother's occupation and her time available to supervise the child is an interesting emerging issue that needs further investigation.

Prolonged neutrophil dysfunction after Plasmodium falciparum malaria is related to hemolysis and heme oxygenase-1 induction.

It is not known why people are more susceptible to bacterial infections such as nontyphoid Salmonella during and after a malaria infection, but in mice, malarial hemolysis impairs resistance to nontyphoid Salmonella by impairing the neutrophil oxidative burst. This acquired neutrophil dysfunction is a consequence of induction of the cytoprotective, heme-degrading enzyme heme oxygenase-1 (HO-1) in neutrophil progenitors in bone marrow. In this study, we assessed whether neutrophil dysfunction occurs in humans with malaria and how this relates to hemolysis. We evaluated neutrophil function in 58 Gambian children with Plasmodium falciparum malaria [55 (95%) with uncomplicated disease] and examined associations with erythrocyte count, haptoglobin, hemopexin, plasma heme, expression of receptors for heme uptake, and HO-1 induction. Malaria caused the appearance of a dominant population of neutrophils with reduced oxidative burst activity, which gradually normalized over 8 wk of follow-up. The degree of neutrophil impairment correlated significantly with markers of hemolysis and HO-1 induction. HO-1 expression was increased in blood during acute malaria, but at a cellular level HO-1 expression was modulated by changes in surface expression of the haptoglobin receptor (CD163). These findings demonstrate that neutrophil dysfunction occurs in P. falciparum malaria and support the relevance of the mechanistic studies in mice. Furthermore, they suggest the presence of a regulatory pathway to limit HO-1 induction by hemolysis in the context of infection and indicate new targets for therapeutic intervention to abrogate the susceptibility to bacterial infection in the context of hemolysis in humans.

Association of Calcium Channel Blocker Use With Intradialytic Hypotension in Maintenance Hemodialysis.

Introduction: Calcium channel blockers (CCBs) are common antihypertensive agents among patients receiving hemodialysis (HD). Despite this, the association of CCBs with intradialytic hypotension (IDH), an important adverse outcome that is associated with cardiovascular morbidity and mortality, remains largely unexplored. Methods: Using kinetic modeling sessions data from the Hemodialysis (HEMO) Study, random effects regression models were fit to assess the association of CCB use versus nonuse with IDH (defined as systolic blood pressure [SBP] < 90 mm Hg if pre-HD SBP < 160 mm Hg or < 100 mm Hg if pre-HD SBP ≥160 mm Hg). Models were adjusted for age, biological sex (distinguishing between males and females), race, randomized Kt/V and flux assignments, heart failure, ischemic heart disease, peripheral vascular disease, diabetes mellitus, blood urea nitrogen, ultrafiltration rate, access type, pre-HD SBP, and other antihypertensives. Results: Data were available for 1838 patients and 64,538 sessions. At baseline, 49% of patients were prescribed CCBs. The overall frequency of IDH was 14% with a mean decline from pre- to nadir-SBP of 33 ± 15 mm Hg. CCB use was associated with lower adjusted risk of IDH, compared with no use (incidence rate ratio [IRR]: 0.84; 95% confidence interval [CI]: 0.78-0.89). The association was most pronounced for those in the pre-HD SBP lowest quartile (IRR: 0.77; 95% CI: 0.70-0.85); compared with the highest quartile (IRR: 0.86; 95% CI: 0.77-0.97; P-interaction < 0.001). Conclusion: Among patients receiving HD, CCB use was associated with a lower risk of developing IDH, independent of pre-HD SBP and other antihypertensives use. Mechanistic studies are needed to better understand the effects of CCB and other antihypertensives on peridialytic blood pressure (BP) parameters among patients receiving HD.

Time of hemodialysis and risk of intradialytic hypotension and intradialytic hypertension in maintenance hemodialysis.

Intradialytic hypotension and intradialytic hypertension are complications of hemodialysis (HD) associated with a higher risk of cardiovascular disease (CVD) and death. Blood pressure (BP) normally fluctuates in a circadian pattern, but whether the risk of intradialytic hypotension and intradialytic hypertension varies according to the time of the HD session is unknown. We analyzed two cohorts of thrice-weekly maintenance HD (N = 1838 patients/n = 64,503 sessions from the Hemodialysis [HEMO] Study, and N = 3302 patients/n = 33,590 sessions from Satellite Healthcare). Random effects logistic regression models examined the association of HD start time (at or before 9:00 a.m. [early AM], between 9:01 a.m. and 12:00 p.m. [late AM], and at or after 12:01 p.m. [PM]) with intradialytic hypotension (defined as nadir intra-HD systolic BP (SBP) < 90 mmHg if pre-HD SBP < 160 mmHg, or <100 mmHg if pre-HD SBP ≥ 160 mmHg) and intradialytic hypertension (SBP increase ≥ 10 mmHg from pre-HD to post-HD). Compared to early AM, late AM and PM were associated with an 8% (aOR 0.92, 95% CI 0.83-1.02) and a 16% (aOR 0.84, 95% CI 0.75-0.95) lower risk of intradialytic hypotension in HEMO, respectively. Conversely, compared to early AM, a monotonic higher risk of intradialytic hypertension was observed for late AM (aOR 1.23, 95% CI 1.12-1.35) and PM (aOR 1.41, 95% CI 1.27-1.56) in HEMO. These findings were consistent in Satellite. In two large cohorts of maintenance HD, we observed a monotonic lower risk of intradialytic hypotension and a monotonic higher risk of intradialytic hypertension with later dialysis start times. Whether HD treatment allocation to certain times of the day in hypotensive-prone or hypertensive-prone patients improves outcomes deserves further investigation.

Stepwise in vitro screening of MMV pathogen box compounds against Plasmodium falciparum to identify potent antimalarial candidates.

Development of resistance to deployed antimalarial drugs is inevitable and needs prompt and continuous discovery of novel candidate drugs. Therefore, the antimalarial activity of 125 compounds from the Medicine for Malaria Ventures (MMV) pathogen box was determined. Combining standard IC50 and normalised growth rate inhibition (GR50) analyses, we found 16 and 22 compounds had higher potencies than CQ respectively. Seven compounds with relatively high potencies (low GR50 and IC50) against P. falciparum 3D7 were further analysed. Three of these were tested on 10 natural P. falciparum isolates from The Gambia using our newly developed parasite survival rate assay (PSRA). According to the IC50, GR50 and PSRA analyses, compound MMV667494 was most potent and highly cytotoxic to parasites. MMV010576 was slow acting but more potent than dihydroartemisinin (DHA) 72 h after exposure. MMV634140 was potent against the laboratory-adapted 3D7 isolate, but 4 out of 10 natural Gambian isolates survived and replicated slowly despite 72 h of exposure to the compound, suggesting potential drug tolerance and risk of resistance development. These results emphasise the usefulness of in vitro testing as a starting point for drug discovery. Improved approaches to data analyses and the use of natural isolates will facilitate the prioritisation of compounds for further clinical development.

Risk of Intradialytic Hypotension by Day of the Week in Maintenance Hemodialysis.

Intradialytic hypotension (IDH) is a common complication of hemodialysis (HD) and is associated with a higher risk of cardiovascular (CV) events and mortality. CV events are more common on the days of HD, especially following the longer interdialytic interval. We investigated the risk of IDH according to day of HD in adults undergoing in-center, thrice-weekly HD in the Hemodialysis (HEMO) Study (N = 1,837 patients; n = 64,474 sessions), and the DaVita Clinical Research biorepository [BioReG]) (N = 952 patients; n = 61,197 sessions). Random effects logistic regression models assessed the risk of IDH (defined as nadir intra-HD systolic blood pressure [SBP] <90 mm Hg if pre-HD SBP <160 mm Hg, or <100 mm Hg if pre-HD SBP ≥160 mm Hg [Nadir90/100 definition]) according to HD day (Mon/Tue [HD1]; Wed/Thu [HD2]; Fri/Sat [HD3]). Alternative definitions of IDH were explored. Nadir90/100 occurred in 14% of HEMO and 18% of BioReG sessions. A monotonic increase in the risk of IDH was observed for HD2 and HD3, compared with HD1, for all IDH definitions in both cohorts. Compared with HD1, HD2 was associated with a 10% higher risk of Nadir90/100 (adjusted odds ratio, 1.10; 95% CI, 1.03-1.17) and HD3 was associated with a 31% higher risk (adjusted odds ratio, 1.31; 95% CI, 1.19-1.45) in HEMO, with consistent results in BioReG. We observed a monotonic increased risk of IDH with later days of the dialytic week in two separate cohorts. Further research to determine the underlying mechanisms is necessary to guide strategies for IDH prevention.

Predialysis serum phosphate and intradialytic hypotension.

INTRODUCTION: Intradialytic hypotension (IDH) is a common complication of hemodialysis (HD) and is associated with excess morbidity and mortality. Higher serum phosphate is associated with adverse cardiovascular outcomes in maintenance HD patients; however, its association with IDH has not previously been assessed. METHODS: This is an analysis of a prospective cohort of 969 HD patients (80,968 HD sessions) receiving HD at a large dialysis organization (LDO) and a post-hoc analysis of 1838 HD patients (10,594 HD sessions) in the Hemodialysis study (HEMO), a multicenter randomized controlled trial that examined standard or high-dose HD and low-flux or high-flux membranes. Unadjusted and adjusted mixed effects regression models were fit to determine the association of pre-HD serum phosphate with IDH, defined as a nadir intra-HD systolic blood pressure (SBP) <90 mmHg. FINDINGS: In the LDO cohort, baseline mean pre-HD serum phosphate was 5.2 ± 1.7 mg/dl. IDH occurred in 15.6% of HD sessions. In the adjusted model, higher pre-HD serum phosphate (per 1 mg/dl) was associated with a 12% increased risk of IDH (aOR 1.12, 95% CI 1.10-1.13, p <0.001). In exploratory models where pre-HD laboratory values were available, the effect estimate was attenuated but remained statistically significant (aOR 1.05; 95% CI 1.02-1.08; p <0.01). Participants in the highest (compared with the lowest) quartile of pre-HD serum phosphate had a 56% greater risk of IDH in the adjusted model (aOR Q4:Q1 1.56; 95% CI 1.44-1.68, p <0.001). The association of higher phosphate with IDH was consistent in the HEMO data. DISCUSSION: Higher pre-HD serum phosphate is independently associated with an increased risk of IDH. As HD may cause an acute decline in serum phosphate, future studies to investigate the mechanisms of this association are warranted.