Interference with Hemozoin Formation Represents an Important Mechanism of Schistosomicidal Action of Antimalarial Quinoline Methanols

Heme is an essential molecule to most living organisms, but once in a free state it exerts toxic effects. Blood-feeding organisms evolved efficient ways to detoxify free heme derived from hemoglobin digestion. A key mechanism present in some hematophagous organisms consists of the crystallization of heme into a pigment named hemozoin. Schistosoma mansoni is one of the etiologic agents of human schistosomiasis, a parasitic disease that affects over 200 million people in tropical and subtropical areas. Hemozoin formation represents the main heme detoxification pathway in S. mansoni. Here, we report that the antimalarial quinoline methanols quinine and quinidine exert schistosomicidal effects notably due to their capacity to interfere with hemozoin formation. When quinine or quinidine were administered intraperitoneally during seven days to S. mansoni-infected mice (75 mg/kg/day), both worm and eggs burden were significantly reduced. Interestingly, hemozoin content in female worms was drastically affected after treatment with either compound. We also found that quinine caused important changes in the cellular organization of worm gastrodermis and increased expression of genes related to musculature, protein synthesis and repair mechanisms. Together, our results indicate that interference with hemozoin formation is a valid chemotherapeutic target for development of new schistosomicidal agents

HIV prevalence and the cascade of care in five South African correctional facilities.

BACKGROUND:South Africa is home to the world's largest HIV epidemic. Throughout the world, incarcerated individuals have a higher prevalence of HIV than the general public, and South Africa has one of the highest rates of incarceration in sub-Saharan Africa. In spite of this, little has been published about the burden of HIV and how care is delivered in South African correctional facilities. OBJECTIVE:To estimate the prevalence of people living with HIV and identify initiation and retention in the HIV cascade of care across five correctional facilities. METHODS:Cross-sectional retrospective analysis of 30,571 adult inmates who participated in a tuberculosis screening and HIV counseling and testing campaign in South African correctional facilities (January 1, 2014-January 31, 2015). Descriptive statistics were used to estimate the proportion and 95% confidence intervals of HIV. Proportions of persons retained and lost at each step in the HIV cascade of care under this intervention were calculated. Poisson regression with robust variance estimates were used, and clustering by facility was accounted for in all analyses. RESULTS:Results of the screening campaign found previously undiagnosed HIV among 13.0% of those consenting to screening, with a total estimated HIV prevalence of 17.7% (n = 3,184, 95% CI: 17.2-18.3%) in the sample. When examining the overall cascade of care, 48.3% of those with HIV initiated care, and overall 45.6% of persons who entered care qualified for ART initiated treatment. A Poisson regression accounting for clustering by facility found HIV high risk groups within the population such as women (aRR = 1.72, 95% CI: 1.57, 1.89), those over 35 years of age (aRR = 2.43, 95% CI: 1.53, 3.85), and people incarcerated less than one year (aRR = 1.41, 95% CI: 1.19, 1.67). CONCLUSION:In this setting, routine screening is recommended, and measures are needed to ensure that persons diagnosed are adequately linked to and retained in care

A series of structurally simple chloroquine chemosensitizing dibemethin derivatives that inhibit chloroquine transport by PfCRT

A series of 12 new dibemethin (N-benzyl-N-methyl-1-phenylmethanamine) derivatives bearing an N-aminomethyl group attached to the one phenyl ring and an H, Cl, OCH3 or N(CH3)2 group on the other have been synthesized. These compounds all showed strong chloroquine chemosensitizing activity, comparable to verapamil, when present at 1 μM in an in vitro culture of the chloroquine-resistant W2 strain of the human malaria parasite, Plasmodium falciparum. Their N-formylated derivatives also exhibited resistance-reversing activity, but only at substantially higher IC10 concentrations. A number of the dibemethin derivatives were shown to inhibit chloroquine transport via the parasite's 'chloroquine resistance transporter' (PfCRT) in a Xenopus laevis oocyte expression system. The reduced resistance-reversing activity of the formylated compounds relative to their free amine counterparts can probably be ascribed to two factors: decreased accumulation of the formylated dibemethins within the parasite's internal digestive vacuole (believed to be the site of action of chloroquine), and a reduced ability to inhibit PfCRT. The resistance-reversing activity of the compounds described here demonstrates that the amino group need not be attached to the two aromatic rings via a three or four carbon chain as has been suggested by previous QSAR studies. These compounds may be useful as potential side chains for attaching to a 4,7-dichloroquinoline group in order to generate new resistance-reversing chloroquine analogues with inherent antimalarial activity

Quinoline Antimalarials Containing a Dibemethin Group are Active against Chloroquinone-Resistant Plasmodium falciparum and Inhibit Chloroquine Transport via the P. falciparum Chloroquine- Resistance Transporter (PfCRT)

A series of 4-amino-7-chloroquinolines with dibenzylmethylamine (dibemethin) side chains were shown to inhibit synthetic hemozoin formation. These compounds were equally active against cultures of chloroquine-sensitive (D10) and chloroquine-resistant (K1) Plasmodium falciparum. The most active compound had an IC50 value comparable to that of chloroquine, and its potency was undiminished when tested in three additional chloroquine-resistant strains. The three most active compounds exhibited little or no cytotoxicity in a mammalian cell line. When tested in vivo against mouse malaria via oral administration, two of the dibemethin derivatives reduced parasitemia by over 99%, with mice treated at 100 mg/kg surviving the full length of the experiment. Three of the compounds were also shown to inhibit chloroquine transport via the parasite's chloroquine-resistance transporter (PfCRT) in a Xenopus oocyte expression system. This constitutes the first example of a dual-function antimalarial for which the ability to inhibit both hemozoin formation and PfCRT has been demonstrated directly

Arrhythmias in Cardiac Sarcoidosis Bench to Bedside: A Case-Based Review

Cardiac sarcoidosis is a component of an often multiorgan granulomatous disease of still uncertain cause. It is being recognized with increasing frequency, mainly as the result of heightened awareness and new diagnostic tests, specifically cardiac magnetic resonance imaging and 18F-fluorodeoxyglucose positron emission tomography scans. The purpose of this case-based review is to highlight the potentially life-saving importance of making the early diagnosis of cardiac sarcoidosis using these new tools and to provide a framework for the optimal care of patients with this disease. We will review disease mechanisms as currently understood, associated arrhythmias including conduction abnormalities, and atrial and ventricular tachyarrhythmias, guideline-directed diagnostic criteria, screening of patients with extracardiac sarcoidosis, and the use of pacemakers and defibrillators in this setting. Treatment options, including those related to heart failure, and those which may help clarify disease mechanisms are included