Time Dependency of Heat-shocking oepm134 and Its Penetrance

UROP paper, 2014, BiologyUndergraduate Research Opportunities Program, University of Minnesota Dulut

Time Dependency of Heat-shocking oepm134 and Its Penetrance

University of Minnesota Duluth 2014 UROP paperSwenson College of Science and Engineering, University of Minnesota Dulut

Auditory assessment of patients with acute uncomplicated Plasmodium falciparum malaria treated with three-day mefloquine-artesunate on the north-western border of Thailand

<p>Abstract</p> <p>Background</p> <p>The use of artemisinin derivatives has increased exponentially with the deployment of artemisinin combination therapy (ACT) in all malarious areas. They are highly effective and are considered safe, but in animal studies artemisinin derivatives produce neurotoxicity targeting mainly the auditory and vestibular pathways. The debate remains as to whether artemisinin derivatives induce similar toxicity in humans.</p> <p>Methods</p> <p>This prospective study assessed the effects on auditory function of a standard 3-day oral dose of artesunate (4 mg/kg/day) combined with mefloquine (25 mg/kg) in patients with acute uncomplicated falciparum malaria treated at the Shoklo Malaria Research Unit, on the Thai-Burmese border. A complete auditory evaluation with tympanometry, audiometry and auditory brainstem responses (ABR) was performed before the first dose and seven days after initiation of the antimalarial treatment.</p> <p>Results</p> <p>Complete auditory tests at day 0 (D0) and day 7 (D7) were obtained for 93 patients. Hearing loss (threshold > 25 dB) on admission was common (57%) and associated with age only. No patient had a threshold change exceeding 10 dB between D0 and D7 at any tested frequency. No patient showed a shift in Wave III peak latency of more than 0.30 msec between baseline and D7.</p> <p>Conclusion</p> <p>Neither audiometric or the ABR tests showed clinical evidence of auditory toxicity seven days after receiving oral artesunate and mefloquine.</p

Fluctuations in Serum magnesium and Systemic Arterial Blood Pressures during the Menstrual Cycle in young reproductive women

Introduction: The menstrual cycle involves a sequence of structural, functional, and hormonal changes in the reproductive system. This is linked and controlled by cyclical fluctuations in the levels of FSH, LH, estrogen, and progesterone. Because of these cyclical fluctuations, there might also be associated cyclical changes of magnesium and systemic arterial blood pressures during the menstrual cycle. Purpose: To assess the changes in serum magnesium level and systemic arterial blood pressures during the menstrual cycle in young reproductive women. Methodology: the sample population is 40 apparently healthy young reproductive-aged 18- 25years female students from the University of Medicine, Magway participated in this study. Systemic arterial blood pressures were measured by indirect method. The serum magnesium level was measured by spectrophotometry. These measurements were done in the early follicular phase (EF), the peri-ovulatory phase (PO), and the midluteal phase (ML) of the menstrual cycle. The serum magnesium levels were significantly (p <0.001) lower, and the systolic blood pressures were significantly higher (p <0.05) in the PO than the EF and the ML. In the EF, there was a significant negative correlation between serum magnesium level and diastolic blood pressure (r= - 0.374, p <0.05) and mean arterial pressure (r = -0.354, p < 0.05) but no significant correlation with systolic blood pressure. In the PO, there was no significant correlation between serum magnesium level and systemic arterial blood pressures. In the ML, there was significant negative correlation between serum magnesium level and systolic blood pressure (r = -0.651, p <0.001), diastolic blood pressure (r = -0.607, p <0.001), and mean arterial pressure (r = -0.661, p <0.001). Conclusion: The study concludes that serum magnesium level has a negative effect on blood pressure changes and the blood pressure-lowering effect of magnesium. These changes are related to the fluctuation of estrogen levels during the menstrual cycle. KEYWORDS: Serum magnesium, systemic arterial blood pressures, menstrual cycle reproductive syste

Methylene Homologues of Artemisone: An Unexpected Structure-Activity Relationship and a Possible Implication for the Design of C10-Substituted Artemisinins.

We sought to establish if methylene homologues of artemisone are biologically more active and more stable than artemisone. The analogy is drawn with the conversion of natural O- and N-glycosides into more stable C-glycosides that may possess enhanced biological activities and stabilities. Dihydroartemisinin was converted into 10β-cyano-10-deoxyartemisinin that was hydrolyzed to the α-primary amide. Reduction of the β-cyanide and the α-amide provided the respective methylamine epimers that upon treatment with divinyl sulfone gave the β- and α-methylene homologues, respectively, of artemisone. Surprisingly, the compounds were less active in vitro than artemisone against P. falciparum and displayed no appreciable activity against A549, HCT116, and MCF7 tumor cell lines. This loss in activity may be rationalized in terms of one model for the mechanism of action of artemisinins, namely the cofactor model, wherein the presence of a leaving group at C10 assists in driving hydride transfer from reduced flavin cofactors to the peroxide during perturbation of intracellular redox homeostasis by artemisinins. It is noted that the carba analogue of artemether is less active in vitro than the O-glycoside parent toward P. falciparum, although extrapolation of such activity differences to other artemisinins at this stage is not possible. However, literature data coupled with the leaving group rationale suggest that artemisinins bearing an amino group attached directly to C10 are optimal compounds. A brief critique is made of proteomic studies purporting to demonstrate the alkylation of intraparasitic proteins by alkyne- and azide-tagged artemisinins and synthetic peroxides in relation to mechanism of action

Validation of N-myristoyltransferase as an antimalarial drug target using an integrated chemical biology approach

Malaria is an infectious disease caused by parasites of the genus Plasmodium, which leads to approximately one million deaths per annum worldwide. Chemical validation of new antimalarial targets is urgently required in view of rising resistance to current drugs. One such putative target is the enzyme N-myristoyltransferase, which catalyses the attachment of the fatty acid myristate to protein substrates (N-myristoylation). Here, we report an integrated chemical biology approach to explore protein myristoylation in the major human parasite P. falciparum, combining chemical proteomic tools for identification of the myristoylated and glycosylphosphatidylinositol-anchored proteome with selective small-molecule N-myristoyltransferase inhibitors. We demonstrate that N-myristoyltransferase is an essential and chemically tractable target in malaria parasites both in vitro and in vivo, and show that selective inhibition of N-myristoylation leads to catastrophic and irreversible failure to assemble the inner membrane complex, a critical subcellular organelle in the parasite life cycle. Our studies provide the basis for the development of new antimalarials targeting N-myristoyltransferase