Physicochemical Characterization of NPC 1161C,A Novel Antimalarial 8-Aminoquinoline,in Solution and Solid State

NPC 1161C is a novel antimalarial drug of interest because of its superior curative and prophylactic activity, and favorable toxicity profile against in vivo and in vitro models of malaria, pneumocystis carinii pneumonia, and leishmaniasis. The preformulation studies performed included determination of pK_as, aqueous and pH solubility, cosolvent solubility, log P, pH stability, thermal analysis, and preliminary hygroscopicity studies. The mean pK_a1, pK_a2, and pK_a3 were determined to be 10.12, 4.07, and 1.88, respectively. The aqueous solubility was found to be 2.4 × 10⁻⁴ M having a saturated solution pH of 4.3–5.0 and a low intrinsic solubility of 1.6 × 10⁻⁶ M. A mathematical model of the pH-solubility profile was derived from pH 2.2 to 8.0. An exponential decrease in solubility was observed with increasing pH. The excess solid phase in equilibrium with the solution in aqueous buffers was determined to be the free-base form of the drug. A significant increase in solubility was observed with all the cosolvents studied, in both unbuffered and buffered systems. Mean log P of the salt and the free base were estimated to be 2.18 and 3.70, respectively. The compound had poor stability at pH 7.0 at 37°C, with a t ₉₀ of 3.58 days. Thermal analysis of the drug using DSC and TGA revealed that the drug is present as a semi-crystalline powder, which transformed into the amorphous state after melting. The drug was also found to sublime at higher temperatures. Determination of physicochemical properties of NPC 1161C provided useful information for the development of a dosage form and preclinical evaluation.     

Genetic susceptibility to acute rheumatic fever: a systematic review and meta-analysis of twin studies

Background

Acute rheumatic fever is considered to be a heritable condition, but the magnitude of the genetic effect is unknown. The objective of this study was to conduct a systematic review and meta-analysis of twin studies of concordance of acute rheumatic fever in order to derive quantitative estimates of the size of the genetic effect.

Methods

We searched PubMed/MEDLINE, ISI Web of Science, EMBASE, and Google Scholar from their inception to 31 January 2011, and bibliographies of retrieved articles, for twin studies of the concordance for acute rheumatic fever or rheumatic heart disease in monozygotic versus dizygotic twins that used accepted diagnostic criteria for acute rheumatic fever and zygosity without age, gender or language restrictions. Twin similarity was measured by probandwise concordance rate and odds ratio (OR), and aggregate probandwise concordance risk was calculated by combining raw data from each study. ORs from separate studies were combined by random-effects meta-analysis to evaluate association between zygosity status and concordance. Heritability was estimated by fitting a variance components model to the data.

Results

435 twin pairs from six independent studies met the inclusion criteria. The pooled probandwise concordance risk for acute rheumatic fever was 44% in monozygotic twins and 12% in dizygotic twins, and the association between zygosity and concordance was strong (OR 6.39; 95% confidence interval, 3.39 to 12.06; P<0.001), with no significant study heterogeneity (P = 0.768). The estimated heritability across all the studies was 60%.

Conclusions

Acute rheumatic fever is an autoimmune disorder with a high heritability. The discovery of all genetic susceptibility loci through whole genome scanning may provide a clinically useful genetic risk prediction tool for acute rheumatic fever and its sequel, rheumatic heart disease.     

Why Don't We Ask? A Complementary Method for Assessing the Status of Great Apes

Species conservation is difficult. Threats to species are typically high and immediate. Effective solutions for counteracting these threats, however, require synthesis of high quality evidence, appropriately targeted activities, typically costly implementation, and rapid re-evaluation and adaptation. Conservation management can be ineffective if there is insufficient understanding of the complex ecological, political, socio-cultural, and economic factors that underlie conservation threats. When information about these factors is incomplete, conservation managers may be unaware of the most urgent threats or unable to envision all consequences of potential management strategies. Conservation research aims to address the gap between what is known and what knowledge is needed for effective conservation. Such research, however, generally addresses a subset of the factors that underlie conservation threats, producing a limited, simplistic, and often biased view of complex, real world situations. A combination of approaches is required to provide the complete picture necessary to engage in effective conservation. Orangutan conservation (Pongo spp.) offers an example: standard conservation assessments employ survey methods that focus on ecological variables, but do not usually address the socio-cultural factors that underlie threats. Here, we evaluate a complementary survey method based on interviews of nearly 7,000 people in 687 villages in Kalimantan, Indonesia. We address areas of potential methodological weakness in such surveys, including sampling and questionnaire design, respondent biases, statistical analyses, and sensitivity of resultant inferences. We show that interview-based surveys can provide cost-effective and statistically robust methods to better understand poorly known populations of species that are relatively easily identified by local people. Such surveys provide reasonably reliable estimates of relative presence and relative encounter rates of such species, as well as quantifying the main factors that threaten them. We recommend more extensive use of carefully designed and implemented interview surveys, in conjunction with more traditional field methods.     

Asbestos-mediated CREB phosphorylation is regulated by protein kinase A and extracellular signal-regulated kinases 1/2

Asbestos is a ubiquitous, naturally occurring fiber that has been linked to the development of malignant and fibrotic lung diseases. Asbestos exposure leads to apoptosis, followed by compensatory proliferation, yet many of the signaling cascades coupled to these outcomes are unclear. Because CREs (Ca(2+)/cAMP-response elements) are found in the promoters of many genes important for regulation of proliferation and apoptosis, CREB (CRE binding protein) is likely to play an important role in the development of asbestos-mediated lung injury. To explore this possibility, we tested the hypotheses that asbestos exposure leads to CREB phosphorylation in lung epithelial cells and that protein kinase A (PKA) and extracellular signal-regulated kinases 1/2 (ERK1/2) are central regulators of the CREB pathway. Persistent CREB phosphorylation was observed in lung sections from mice following inhalation of crocidolite asbestos. Exposure of C10 lung epithelial cells to crocidolite asbestos led to rapid CREB phosphorylation and apoptosis that was decreased by the inhibition of PKA or ERK1/2 using the specific inhibitors H89 and U0126, respectively. Furthermore, crocidolite asbestos selectively induced a sustained increase in MAP kinase phosphatase-1 mRNA and protein. Silencing CREB protein dramatically reduced asbestos-mediated ERK1/2 phosphorylation, yet significantly increased the number of cells undergoing asbestos-induced apoptosis. These data reveal a novel and selective role for CREB in asbestos-mediated signaling through pathways regulated by PKA and ERK1/2, further providing evidence that CREB is an important regulator of apoptosis in asbestos-induced responses of lung epithelial cells.     

Effect of chlorate,molybdate, and shikimic acid on Salmonella enterica serovar Typhimurium in aerobic and anaerobic cultures

Experiments were conducted to determine factors that affect sensitivity of Salmonella enterica serovar Typhimurium to sodium chlorate (5 mM). In our first experiment, cultures grown without chlorate grew more rapidly than those with chlorate. An extended lag before logarithmic growth was observed in anaerobic but not aerobic cultures containing chlorate. Chlorate inhibition of growth during aerobic culture began later than that observed in anaerobic cultures but persisted once inhibition was apparent. Conversely, anaerobic cultures appeared to adapt to chlorate after approximately 10 h of incubation, exhibiting rapid compensatory growth. In anaerobic chlorate-containing cultures, 20% of total viable counts were resistant to chlorate by 6 h and had propagated to 100% resistance (>10⁹ CFU mL^?1) by 24 h. In the aerobic chlorate-containing cultures, 12.9% of colonies had detectable resistance to chlorate by 6 h, but only 1% retained detectable resistance at 24 h, likely because these cultures had opportunity to respire on oxygen and were thus not enriched via the selective pressure of chlorate. In another study, treatment with shikimic acid (0.34 mM), molybdate (1 mM) or their combination had little effect on aerobic or anaerobic growth of Salmonella in the absence of added chlorate. As observed in our earlier study, chlorate resistance was not detected in any cultures without added chlorate. Chlorate resistant Salmonella were recovered at equivalent numbers regardless of treatment after 8 h of aerobic or anaerobic culture with added chlorate; however, by 24 h incubation chlorate sensitivity was completely restored to aerobic but not anaerobic cultures treated with shikimic acid or molybdate but not their combination. Results indicate that anaerobic adaptation of S. Typhimurium to sodium chlorate during pure culture is likely due to the selective propagation of low numbers of cells exhibiting spontaneous resistance to chlorate and this resistance is not reversible by molybdenum supplementation.     

Pillar Function in the Fiddler Crab Uca beebei (I): Effects on Male Spacing and Aggression

Males of 14 species of fiddler crabs (genus Uca) are known to build structures out of mud or sand at the entrances to burrows they court from and defend. A study of spacing, space use and aggression between courting male Uca musica (Zucker 1974, 1981) suggested that the hoods males build reduce territorial overlap and rates of aggression between neighboring males. Thus, each male may have more time to court females during limited lunar, diurnal and tidal mating periods. I studied the courtship and aggressive behavior of male Uca beebei in the field to determine if the pillars males of this species build affect male behavior as do the hoods of U. musica. U. beebei occurs sympatrically with U. musica on the Pacific coast of Panama and is broadly similar in its ecology and mating behavior. Unlike the hoods of U. musica, pillars did not focus a male's activity space away from its closest neighbor nor did they reduce either overlap with neighbors' activity spaces or rates of aggressive interaction among neighbors. Pillar builders courted more but also fought their neighbors more than did males that did not build pillars. The pillars of U. beebei and the hoods of U. musica affect male behavior differently and probably have different functions.     

Chloroplast and nuclear microsatellite analysis of Aegilops cylindrica

Aegilops cylindrica Host (2n=4x=28, genome CCDD) is an allotetraploid formed by hybridization between the diploid species Ae. tauschii Coss. (2n=2x=14, genome DD) and Ae. markgrafii (Greuter) Hammer (2n=2x=14, genome CC). Previous research has shown that Ae. tauschii contributed its cytoplasm to Ae. cylindrica. However, our analysis with chloroplast microsatellite markers showed that 1 of the 36 Ae. cylindrica accessions studied, TK 116 (PI 486249), had a plastome derived from Ae. markgrafii rather than Ae. tauschii. Thus, Ae. markgrafii has also contributed its cytoplasm to Ae. cylindrica. Our analysis of chloroplast and nuclear microsatellite markers also suggests that D-type plastome and the D genome in Ae. cylindrica were closely related to, and were probably derived from, the tauschii gene pool of Ae. tauschii. A determination of the likely source of the C genome and the C-type plastome in Ae. cylindrica was not possible.     

Multiple processing body factors and the ARE binding protein TTP activate mRNA decapping

Decapping is a key step in mRNA turnover. However, the composition and regulation of the human decapping complex is poorly understood. Here, we identify three proteins that exist in complex with the decapping enzyme subunits hDcp2 and hDcp1: hEdc3, Rck/p54, and a protein in decapping we name Hedls. Hedls is important in decapping because it enhances the activity of the catalytic hDcp2 subunit and promotes complex formation between hDcp2 and hDcp1. Specific decapping factors interact with the mRNA decay activators hUpf1 and TTP, and TTP enhances decapping of a target AU-rich element (ARE) RNA in vitro. Each decapping protein localizes in cytoplasmic processing bodies (PBs), and overexpression of Hedls produces aberrant PBs and concomitant accumulation of a deadenylated ARE-mediated mRNA decay intermediate. These observations suggest that multiple proteins involved in human decapping are important subunits of PBs and are activated on ARE-mRNAs by the protein TTP.