Publications

Piperaquine, new findings

No abstract is provided for this article.

Artemether in severe malaria

Twenty-year co-evolutionary arms race between meerkat MHC and Tuberculosis

<title>Abstract</title> Pathogen-mediated balancing selection shapes host ecology and evolution across the tree of life, fueling a co-evolutionary arms race based on frequency-dependent adaptations of hosts and counter-adaptations of pathogens. While rare immune genotypes are predicted to be more resistant to pathogens, evidence for this rare allele-advantage and negative frequency-dependent feedbacks has only been observed in model species or inferred from short-term field observations. Evidence from long-term data and wild populations is missing. Here, we leverage two decades of immune genetic and disease surveillance data from over 1,500 wild meerkats (<italic>Suricata suricatta</italic>) to reveal co-evolutionary dynamics between the Major Histocompatibility Complex (MHC) and <italic>Mycobacterium suricattae</italic>, causing tuberculosis (TB). We uncover fluctuating adaptive MHC allelic, functional and haplotypic diversity over time compared with stable neutral genetic diversity. Crucially, we show that meerkats carrying the MHC allele Susu-DRB*13 faced initially higher TB infection probability, with the effect reversing over the course of the study, followed again by an increase in frequency of Susu-DRB*13. Similarly, TB progression first accelerated in meerkats carrying Susu-DRB*13, but decelerated thereafter. Susu-DRB*13 (and its supertype/haplotype) also prolonged survival in individuals with clinical TB. Our results present strong evidence that the rare allele-advantage propels negative frequency-dependent selection in a wild mammal. We discuss meerkats’ social structure as possible reasons for these comparably rapid co-evolutionary dynamics.

In‐host modeling of dengue virus and non‐structural protein 1 and the effects of ivermectin in patients with acute dengue fever

The increased incidence of dengue poses a substantially global public health challenge. There are no approved antiviral drugs to treat dengue infections. Ivermectin, an old anti-parasitic drug, had no effect on dengue viremia, but reduced the dengue non-structural protein 1 (NS1) in a clinical trial. This is potentially important, as NS1 may play a causal role in the pathogenesis of severe dengue. This study established an in-host model to characterize the plasma kinetics of dengue virus and NS1 with host immunity and evaluated the effects of ivermectin, using a population pharmacokinetic-pharmacodynamic (PK-PD) modeling approach, based on two studies in acute dengue fever: a placebo-controlled ivermectin study in 250 adult patients and an ivermectin PK-PD study in 24 pediatric patients. The proposed model described adequately the observed ivermectin pharmacokinetics, viral load, and NS1 data. Bodyweight was a significant covariate on ivermectin pharmacokinetics. We found that ivermectin reduced NS1 with an EC

Supplementary material from "Intergroup aggression in meerkats"

Violent conflicts between groups have been observed among many species of group living mammals and can have important fitness consequences, with individuals being injured or killed and with losing groups surrendering territory. Here, we explore between-group conflict among meerkats (Suricata suricatta), a highly social and cooperatively breeding mongoose. We show that interactions between meerkat groups are frequently aggressive and sometimes escalate to fighting and lethal violence and that these interactions have consequences for group territories, with losing groups moving to sleeping burrows closer to the centre of their territories following an intergroup interaction and with winning groups moving further away. We find that larger groups and groups with pups are significantly more likely to win contests, but that the location of the contest, adult sex ratio, and mean within-group genetic relatedness do not predict contest outcome. Our results suggest that intergroup competition may be a major selective force among meerkats, reinforcing the success of large groups and increasing the vulnerability of small groups to extinction. The presence of both within-group cooperation and between-group hostility in meerkats make them a valuable point of comparison in attempts to understand the ecological and evolutionary roots of human warfare.

Oral Artesunate in the Treatment of Uncomplicated Hyperparasitemic Falciparum Malaria

Patients with uncomplicated hyperparasitemic falciparum malaria are usually given parenteral antimalarial treatment to prevent a progression to vital organ dysfunction and death. Since the oral artemisinin derivatives are more rapidly effective than other antimalarial drugs, we compared oral artesunate (4 mg/kg/day for three days with mefloquine 25 mg/kg on the second day) with an intravenous quinine loading dose (20 mg of salt/kg initially then 10 mg/kg every 8 hr, followed by mefloquine 25 mg/kg) in an open paired randomized trial in 60 patients with acute falciparum malaria and greater than 4% parasitemia, but no evidence of vital organ dysfunction. There were no deaths and none of the patients progressed to develop severe malaria. Oral artesunate treatment resulted in shorter median [range] times to fever clearance (19 hr [4–45] versus 47 hr [4–107]) (P < 0.0001), parasite clearance (36 hr [18–61] versus 82 hr [36–140]) (P < 0.0001), and discharge from the hospital (25 hr [12–44] versus 58 hr [24–115]) (P < 0.0001). There was no toxicity attributable to artesunate. The cure rates by day 28 were 70% (19 of 27) and 39% (11 of 27) in the artesunate and quinine groups, respectively (relative risk = 1.7; 95% confidence interval = 1.0–3.0). Oral artesunate was simpler, cheaper, safer, and more effective than intravenous quinine for the treatment of uncomplicated hyperparasitemia.

Inactivation of thyrotrophin releasing hormone (TRH) by peptidase in different areas of the rabbit brain

No abstract is provided for this article.

Phenological sensitivity to climate across taxa and trophic levels

No abstract is provided for this article.

Relationship between age and microvascular filtration capacity in man.

No abstract is provided for this article.

Single Low Dose Primaquine (0.25mg/kg) Does Not Cause Clinically Significant Haemolysis in G6PD Deficient Subjects

Background Primaquine is the only drug consistently effective against mature gametocytes of Plasmodium falciparum. The transmission blocking dose of primaquine previously recommended was 0.75mg/kg (adult dose 45mg) but its deployment was limited because of concerns over haemolytic effects in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency. G6PD deficiency is an inherited X-linked enzymatic defect that affects an estimated 400 million people around the world with high frequencies (15–20%) in populations living in malarious areas. To reduce transmission in low transmission settings and facilitate elimination of P. falciparum, the World Health Organization now recommends adding a single dose of 0.25mg/kg (adult dose 15mg) to Artemisinin-based Combination Therapies (ACTs) without G6PD testing. Direct evidence of the safety of this low dose is lacking. Adverse events and haemoglobin variations after this treatment were assessed in both G6PD normal and deficient subjects in the context of targeted malaria elimination in a malaria endemic area on the North-Western Myanmar-Thailand border where prevalence of G6PD deficiency (Mahidol variant) approximates 15%. Methods and Findings The tolerability and safety of primaquine (single dose 0.25 mg base/kg) combined with dihydroartemisinin-piperaquine (DHA-PPQ) given three times at monthly intervals was assessed in 819 subjects. Haemoglobin concentrations were estimated over the six months preceding the ACT + primaquine rounds of mass drug administration. G6PD deficiency was assessed with a phenotypic test and genotyping was performed in male subjects with deficient phenotypes and in all females. Fractional haemoglobin changes in relation to G6PD phenotype and genotype and primaquine round were assessed using linear mixed-effects models. No adverse events related to primaquine were reported during the trial. Mean fractional haemoglobin changes after each primaquine treatment in G6PD deficient subjects (-5.0%, -4.2% and -4.7%) were greater than in G6PD normal subjects (0.3%, -0.8 and -1.7%) but were clinically insignificant. Fractional drops in haemoglobin concentration larger than 25% following single dose primaquine were observed in 1.8% of the population but were asymptomatic. Conclusions The single low dose (0.25mg/kg) of primaquine is clinically well tolerated and can be used safely without prior G6PD testing in populations with high prevalence of G6PD deficiency. The present evidence supports a broader use of low dose primaquine without G6PD testing for the treatment and elimination of falciparum malaria. Trial Registration ClinicalTrials.gov NCT01872702

Correction to: The use of ultrasensitive quantitative-PCR to assess the impact of primaquine on asymptomatic relapse of Plasmodium vivax infections: a randomized, controlled trial in Lao PDR

Following publication of the original article [1], it was brought to the authors’ attention that one of the names in the author list had been provided with the incorrect spelling.

Facial paralysis secondary to acute otitis media

We describe a case of facial paralysis in a 19-month-old male recently diagnosed with acute otitis media. Results of his physical examination was remarkable for left-sided peripheral facial nerve palsy with an associated middle ear infection. Physicians should understand the etiology, pathophysiology, treatment options, and prognosis of facial palsy in association with otitis media.

Experimental peripheral administration of oxytocin elevates a suite of cooperative behaviours in a wild social mammal

The evolution and expression of different forms of cooperative behaviour (e.g. feeding, guarding, sentinel duties, etc.) are usually studied independently, with few studies considering them as a single syndrome. However, studies investigating individuals' investment across a suite of different behaviours reveal that they are correlated, suggesting a single mechanism determining the evolution and expression of cooperative behaviours. A hormonal mechanism could achieve this, and one possibility is oxytocin (OT), which affects several prosocial or alloparental behaviours independently. We show, using a double-blind experiment, that peripheral administration of OT to social, free-living meerkats Suricata suricatta elevates a suite of cooperative behaviours. Treated individuals increase their contributions to communal, cooperative activities (digging, guarding, pup-feeding and associating with pups) and decrease initiation of aggressive interactions, compared with a saline control. This suggests that different forms of cooperative behaviour form a single syndrome with a common causal basis. If our peripherally administered OT acts in the same way as the naturally released hormone, then a general tendency to prosociality may be modulated by this hormonal system. Therefore, it may be difficult for an individual to decouple expression of cooperative behaviours that provide the practitioner with benefits from those that provide the recipient with benefits. It may also explain why social species typically exhibit a suite of cooperative behaviours, without having to invoke independent evolution of each.

Detection of Pseudomonas pseudomallei Antigen in Urine for the Diagnosis of Melioidosis

An enzyme-linked immunosorbent assay using a fluorescein isothiocyanate (FITC)-anti-FITC amplification system, has been developed to detect Pseudomonas pseudomallei antigen in urine. The assay was evaluated in 135 patients with acute melioidosis, 194 hospitalized patients with other disorders, and 40 healthy controls. Antigen was detected in the urine of 123 (91%) patients with melioidosis. Urinary antigen was found in 85 (96%) of 89 patients with septicemic melioidosis, all six patients with P. pseudomallei urinary tract infection, and 32 (80%) of 40 patients with other localized infections. Antigen was not detected in the urine of 40 healthy individuals, but the urine of 16 (8%) of 194 hospitalized patients with diagnoses other than melioidosis gave a positive results. Of the false-positive results, 13 of 16 were associated with bacteriuria ≥ 104 colony-forming units/ml. At a cutoff titer of 1:10, the sensitivity and specificity of the test were 81% and 96%, respectively. Enzyme immunoassay detection of urinary antigen is a valuable and rapid laboratory test for the early diagnosis of acute melioidosis.

Managing cerebral malaria.

No abstract is provided for this article.

Increased Utilization of Fusion with Instrumentation and BMP in the Medicare Patient Population Over Time

No abstract is provided for this article.

Antimalarial Drug Toxicity

No abstract is provided for this article.

A new approach to evaluate regression models during validation of bioanalytical assays

The quality of bioanalytical data is highly dependent on using an appropriate regression model for calibration curves. Non-weighted linear regression has traditionally been used but is not necessarily the optimal model. Bioanalytical assays generally benefit from using either data transformation and/or weighting since variance normally increases with concentration. A data set with calibrators ranging from 9 to 10000ng/mL was used to compare a new approach with the traditional approach for selecting an optimal regression model. The new approach used a combination of relative residuals at each calibration level together with precision and accuracy of independent quality control samples over 4 days to select and justify the best regression model. The results showed that log–log transformation without weighting was the simplest model to fit the calibration data and ensure good predictability for this data set.