Metabolism of DHEA in postmenopausal women following percutaneous administration

The marked decline in serum dehydroepiandrosterone (DHEA) with age is believed to play a role in health problems associated with aging, these health issues being potentially preventable or reversible by the exogenous administration of DHEA. In the present study, liquid chromatography/mass spectrometry/mass spectrometry (LC/MS/MS) and gas chromatrography/mass spectrometry (GC/MS) were used to measure the serum levels of DHEA and 11 of its metabolites in seventy-five 60-65-year-old Caucasian women who received 3g of 0.1%, 0.3%, 1.0% or 2.0% DHEA cream or placebo applied twice daily on the face, upper chest, arms and legs. The serum levels of DHEA increased 574% over control at the 2.0% DHEA dose while the sum of the androgen metabolites androsterone glucuronide (ADT-G), 3alpha-androstenediol-3G (3alpha-diol-3G) and 3alpha-diol-17G increased by only 231%. On the other hand, serum testosterone and dihydrosterone were increased by 192% and 275%, respectively, above basal levels compared to 139% and 158% for estrone and estradiol. Such data show that the transformation of exogenous DHEA in postmenopausal women is preferentially into androgens rather than into estrogens. On the other hand, the present data indicate that serum DHEA measurements following DHEA supplementation in postmenopausal women are an overestimate of the formation of active androgens and estrogens and suggest a decreased efficiency of transformation of DHEA into androgens and estrogens with aging.     

1,4-Dihydroindeno[1,2-c]pyrazoles as potent checkpoint kinase 1 inhibitors: extended exploration on phenyl ring substitutions and preliminary ADME/PK studies

A study on substitutions at the four open positions on the phenyl ring of the 1,4-dihydroindeno[1,2-c]pyrazoles as potent CHK-1 inhibitors is described. Bis-substitution at both the 6- and 7-positions led to inhibitors with IC(50) values below 0.3nM. The compound with the best overall activities (36) was able to potentiate the anti-proliferative effect of doxorubicin in HeLa cells by at least 47-fold. Physicochemical, metabolic, and pharmacokinetic properties of selected inhibitors are also disclosed.     

Human TH17 lymphocytes promote blood-brain barrier disruption and central nervous system inflammation

T(H)17 lymphocytes appear to be essential in the pathogenesis of numerous inflammatory diseases. We demonstrate here the expression of IL-17 and IL-22 receptors on blood-brain barrier endothelial cells (BBB-ECs) in multiple sclerosis lesions, and show that IL-17 and IL-22 disrupt BBB tight junctions in vitro and in vivo. Furthermore, T(H)17 lymphocytes transmigrate efficiently across BBB-ECs, highly express granzyme B, kill human neurons and promote central nervous system inflammation through CD4+ lymphocyte recruitment.     

Natural and manipulated populations of the treehole mosquito, Ochlerotatus triseriatus, at its northernmost range limit in southern Ontario, Canada.

Ochlerotatus triseriatus, the eastern treehole mosquito, reaches its northernmost range limit in the extreme southeast of Canada. As a known vector of West Nile and La Crosse encephalitis viruses and a potential vector of eastern equine encephalitis, its population biology is of interest. In southern Ontario, high larval densities occur in urban woodlots within sugar maple and American beech treehole communities comprising rotifers, nematode worms, mites, other dipterans, and scirtid beetles. Treehole water was characterized by low dissolved oxygen levels and seasonally variable pH and temperature, with the latter being most influential on local populations. Densities were significantly higher (up to 503 larvae 100 ml(-1)) in tree holes close to the forest floor (<1 m) and in experimental tree holes seeded with autumn-shed maple leaves as opposed to leaves of black oak and beech. In this locality, weekly sampling showed Oc. triseriatus to be multivoltine, with mass egg hatching beginning under coldwater (<10 degrees C) conditions in March/April, and thereafter producing three successful generations with a possible, less successful fourth in late summer. Some 1st instar larvae were present in water as cold as 0.7 degree C. Compared with larval psychodids living in the same tree hole, population losses of Oc. triseriatus due to washout during major rainfall events were negligible despite high flowthrough of water derived from stemflow.     

Surprising arginine biosynthesis: a reappraisal of the enzymology and evolution of the pathway in microorganisms.

Major aspects of the pathway of de novo arginine biosynthesis via acetylated intermediates in microorganisms must be revised in light of recent enzymatic and genomic investigations. The enzyme N-acetylglutamate synthase (NAGS), which used to be considered responsible for the first committed step of the pathway, is present in a limited number of bacterial phyla only and is absent from Archaea. In many Bacteria, shorter proteins related to the Gcn5-related N-acetyltransferase family appear to acetylate l-glutamate; some are clearly similar to the C-terminal, acetyl-coenzyme A (CoA) binding domain of classical NAGS, while others are more distantly related. Short NAGSs can be single gene products, as in Mycobacterium spp. and Thermus spp., or fused to the enzyme catalyzing the last step of the pathway (argininosuccinase), as in members of the Alteromonas-Vibrio group. How these proteins bind glutamate remains to be determined. In some Bacteria, a bifunctional ornithine acetyltransferase (i.e., using both acetylornithine and acetyl-CoA as donors of the acetyl group) accounts for glutamate acetylation. In many Archaea, the enzyme responsible for glutamate acetylation remains elusive, but possible connections with a novel lysine biosynthetic pathway arose recently from genomic investigations. In some Proteobacteria (notably Xanthomonadaceae) and Bacteroidetes, the carbamoylation step of the pathway appears to involve N-acetylornithine or N-succinylornithine rather than ornithine. The product N-acetylcitrulline is deacetylated by an enzyme that is also involved in the provision of ornithine from acetylornithine; this is an important metabolic function, as ornithine itself can become essential as a source of other metabolites. This review insists on the biochemical and evolutionary implications of these findings.     

The thorough screening of the MUTYH gene in a large French cohort of sporadic colorectal cancers

The MUTYH gene encodes a key glycosylase of the base-excision repair system that is involved in maintaining genomic DNA stability against oxidative damage. Biallelic germline MUTYH mutations have been proved to greatly predispose to non-familial adenomatous polyposis (FAP) and non-hereditary non-polyposis colorectal cancer (HNPCC) familial recessive forms of colorectal cancer with multiple adenomas. To date, there is still much debate over the impact of monoallelic germline MUTYH mutations on colorectal carcinogenesis. To evaluate their role in the susceptibility to sporadic colon and rectum cancers, we screened 1024 French sporadic colorectal cancer cases and 1121 French healthy controls for Caucasian MUTYH-associated polyposis mutations, including already known mutations p.Gly382Asp and p.Tyr165Cys, and new mutation p.Val479Phe. We observed a nonstatistically significant association between these MUTYH mutations at a heterozygous state and an increase in colorectal cancer risk (odds ratio [OR] 1.26, 95% confidence interval [CI] 0.70-2.27). As a result, we conclude that heterozygous MUTYH mutations do not play a major role in sporadic colorectal carcinogenesis although a modest effect on this process cannot be ruled out.     

Differential assay for high-throughput screening of antibacterial compounds

The previously described Bacillus subtilis reporter strain BAU-102 is capable of detecting cell wall synthesis inhibitors that act at all stages of the cell wall synthesis pathway. In addition, this strain is capable of detecting compounds with hydrophobic/surfactant activity and alternative mechanisms of cell wall disruption. BAU-102 sequesters preformed beta-gal in the periplasm, suggesting leakage of beta-gal as the means by which this assay detects compound activities. A model is proposed according to which beta-gal release by BAU-102 reflects activation of pathways leading to autolysis. The authors also report a simplified high-throughput assay using BAU-102 combined with the fluorogenic substrate N-methylumbelliferyl-beta-D-galactoside as a single reagent. Cell wall inhibitors release beta-gal consistently only after 60 min of incubation, whereas compounds with surfactant activity show an almost immediate release. A high-throughput screen of a 480-compound library of known bioactives yielded 8 compounds that cause beta-gal release. These results validate the BAU-102 assay as an effective tool in antimicrobial drug discovery.     

Unity in diversity: Lessons from macaque societies

The macaque radiation is as old as the hominin radiation, approximately 7 million years. After Homo, Macaca has the widest geographical range among primates, and both of these genera are present in tropical and temperate regions as well. Whereas the single extant representative of the genus Homo diverged through processes of cultural diversification, extant species of macaques emerged through processes of evolutionary diversification. Macaque societies are characterized by profound unity and great diversity, and can best be described as variations on the same theme. To understand macaque variation and adaptation, we must take into account the processes that insure the persistence of their societies across generations and environments.