A physical properties based approach for the exploration of a 4-hydroxybenzothiazolone series of β2-adrenoceptor agonists as inhaled long-acting bronchodilators

The chiral synthesis of a 4-hydroxybenzothiazolone based series of β₂-adrenoceptor agonists is described. Using this methodology a library of N-substituted analogues were prepared for the rapid identification of leads with the potential to be fast onset and long-acting inhaled bronchodilators with improved therapeutic margins. The design of the library to achieve the targeted profile was based upon lipophilicity and metabolism based hypotheses. This approach identified β-phenethyl, α-substituted cyclopentyl and monoterpene N-substituents to be of particular interest for further evaluation, as exemplified by structures 19, 29 and 33, respectively.     

Duration of protection against malaria and anaemia provided by intermittent preventive treatment in infants in Navrongo, Ghana

Background

Intermittent preventive treatment for malaria in Infants (IPTi) has been shown to give effective and safe protection against malaria. It has been suggested that IPTi might have long-lasting beneficial effects but, in most settings, the protection provided by IPTi appears to be short-lived. Knowledge of the duration of protection given by IPTi would help interpret the results of existing trials and suggest optimal delivery schedules for IPTi. This study investigated how the protective efficacy of IPTi against malaria and anaemia changes over time.

Methods and Findings

A secondary analysis of data from a cluster-randomised, placebo-controlled trial of IPTi using sulfadoxine-pyrimethamine (SP) in Ghana was conducted. In this trial IPTi was given to 2485 infants at 3, 4, 9 and 12 months of age; children remained in follow-up until two years of age. Poisson regression with a random effect to adjust for the cluster-randomised design was used to determine protective efficacy of IPTi against clinical malaria and anaemia in defined time strata following administration of IPTi. Analysis of first-or-only clinical malaria episode following the individual IPTi doses showed that some protection against malaria lasted between 4 to 6 weeks. A similar pattern was seen when the incidence of all malaria episodes up to 2 years of age was analysed in relation to the most recent IPT, by pooling the incidence of malaria after the individual IPTi doses. Protective efficacy within four weeks of IPTi was 75.2% (95% CI: 66–82) against malaria, 78.9% (95% CI: 69–86) against high parasite density malaria, and 93.8% (95% CI: 73–99) against anaemia. Protection against these outcomes was short-lived, with evidence of any effect lasting for only 6, 6 and 4 weeks respectively. Protection in children who were parasitaemic when receiving IPTi appeared to be of shorter duration than in uninfected children. There was no evidence of any benefit of IPTi after the immediate period following the IPTi doses.

Conclusions

Intermittent preventive treatment provides considerable protection against malaria and anaemia for short periods, even in an area of intense seasonal transmission. Due to the relatively short duration of protection provided by each dose of IPTi, this treatment will be of most benefit when delivered at the time of peak malaria incidence.     

Insight into the mechanism of inactivation and pH sensitivity in potassium channels from molecular dynamics simulations

Potassium (K (+)) channels can regulate ionic conduction through their pore by a mechanism, involving the selectivity filter, known as C-type inactivation. This process is rapid in the hERG K (+) channel and is fundamental to its physiological role. Although mutations within hERG are known to remove this process, a structural basis for the inactivation mechanism has yet to be characterized. Using MD simulations based on homology modeling, we observe that the carbonyl of the filter aromatic, Phe627, forming the S 0 K (+) binding site, swiftly rotates away from the conduction axis in the wild-type channel. In contrast, in well-characterized non-inactivating mutant channels, this conformational change occurs less frequently. In the non-inactivating channels, interactions with a water molecule located behind the selectivity filter are critical to the enhanced stability of the conducting state. We observe comparable conformational changes in the acid sensitive TASK-1 channel and propose a common mechanism in these channels for regulating efflux of K (+) ions through the selectivity filter.     

Identification and mapping of human saphenous vein medial smooth muscle proteins by two-dimensional polyacrylamide gel electrophoresis

Changing smooth muscle phenotype and abnormal cell proliferation are important features of vascular pathology, including the failure of saphenous vein bypass grafts. We have characterised and mapped protein expression in human saphenous vein medial smooth muscle, using two-dimensional (2-D) polyacrylamide gel electrophoresis. The 2-D system comprised a nonlinear immobilised pH 3-10 gradient in the first dimension (separating proteins with isoelectric point values between pH 3-10), and 12%T total gel concentration sodium dodecyl sulphate polyacrylamide gel electrophoresis in the second dimension (separating proteins in the range 14,000-200,000 Daltons). Using a combination of peptide mass fingerprinting by matrix-assisted laser desorption/ionisation-time of flight mass spectrometry and partial amino acid sequencing by nanospray tandem mass spectrometry, a subset of 149 protein spots was analysed, with 129 protein spots being identified and mapped. The data presented here are an important addition to the limited knowledge of venous medial smooth muscle protein expression in vivo. Our protein map will facilitate the identification of proteins differentially expressed in human saphenous vein bypass grafts. In turn, this may lead to the elucidation of molecular events involved in saphenous vein bypass graft failure. The map should also provide a basis for comparative studies of protein expression in vascular smooth muscle of varying origins.     

Cutting edge: identification of a novel chemokine receptor that binds dendritic cell- and T cell-active chemokines including ELC, SLC, and TECK

Searching for new receptors of dendritic cell- and T cell-active chemokines, we used a combination of techniques to interrogate orphan chemokine receptors. We report here on human CCX CKR, previously represented only by noncontiguous expressed sequence tags homologous to bovine PPR1, a putative gustatory receptor. We employed a two-tiered process of ligand assignment, where immobilized chemokines constructed on stalks (stalkokines) were used as bait for adhesion of cells expressing CCX CKR. These cells adhered to stalkokines representing ELC, a chemokine previously thought to bind only CCR7. Adhesion was abolished in the presence of soluble ELC, SLC (CCR7 ligands), and TECK (a CCR9 ligand). Complete ligand profiles were further determined by radiolabeled ligand binding and competition with >80 chemokines. ELC, SLC, and TECK comprised high affinity ligands (IC50 <15 nM); lower affinity ligands include BLC and vMIP-II (IC50 <150 nM). With its high affinity for CC chemokines and homology to CC receptors, we provisionally designate this new receptor CCR10.     

MHC-assortative facial preferences in humans

Individuals tend to choose mates who are sufficiently genetically dissimilar to avoid inbreeding. As facial attractiveness is a key factor in human mate preference, we investigated whether facial preferences were related to genetic dissimilarity. We asked female volunteers to rate the attractiveness of men from photographs and compared these results with individual genotypes at the major histocompatibility complex (MHC). In contrast to previously reported preferences based on odour, we found a non-significant tendency for women to rate MHC-similar faces as more attractive, suggesting a preference for cues to a self-similar MHC in faces. Further analysis revealed that male faces received higher attractiveness scores when rated by women who were MHC-similar than by MHC-dissimilar women. Although unexpected, this MHC-similar facial preference is consistent with other studies documenting assortative preferences in humans, including for facial phenotype.     

Species relationships and population structure of Littorina saxatilis Olivi and L. tenebrosa Montagu in Ireland using single-strand conformational polymorphisms (SSCPs) of cytochrome b fragments

Littorina saxatilis is a ubiquitous snail of intertidal habitats in the North Atlantic. Shell type in littorinids is extremely polymorphic and defined by habitat. Taxonomy based upon shell type has been revised in the light of anatomic and genetic information, but uncertainties remain. In this study, the population structure of L. saxatilis and L. tenebrosa was studied at 11 sites in Ireland using single-strand conformational polymorphisms of a 375-bp portion of the cytochrome b gene, and the status of L. tenebrosa, the small, fragile-shelled, brackish water type, was considered. The genetic patterns among L. saxatilis and L. tenebrosa populations were examined over varying distances and L. tenebrosa was compared with adjacent L. saxatilis populations at four sites on the west coast of Ireland and one site on the east coast. Haplotype diversity was high with 32 haplotypes present among 995 individuals. Pairwise tests suggest gene flow over small scales among and between habitat types and may reflect the stochastic legacy of postglacial recolonization over larger scales. In AMOVA tests, geography explained nearly twice as much of the variance (30%) as habitat type (18%), indicating that gene flow is more restricted by distance than by habitat type, and supporting the status of L. tenebrosa as an ecotype of L. saxatilis rather than a separate species.     

Body odor similarity in noncohabiting twins

There is currently considerable interest in biometric approaches using human odor as a marker of disease or genetic individuality. Body odor is also thought to be used during mate choice to select genetically compatible mates. The idea that body odor reveals information about both genetic identity and genetic similarity is most readily tested by examining odor in twin pairs. However, although this idea can be traced back 130 years to Francis Galton in 1875, most studies using dogs fail to control for shared environmental effects associated with cohabitation. Here we show that odors of identical twins (but not dizygotic twins) can be matched by human sniffers at rates better than chance, even when the twins are living apart. In addition, matching frequencies for identical twin odors were not significantly different from those for duplicate odors from the same individual. These results indicate an important genetic influence on body odor and the potential for developing technologies for human odor printing in relation to underlying genotype.     

The organization of serotonin-, dopamine-, and FMRFamide- containing neuronal elements and their possible role in the regulation of spontaneous contraction of the gastrointestinal tract in the snail Helix pomatia

Summary The distribution of serotonin-, tyrosine hydroxylase-, and FMRFamide-immunoreactive neuronal elements, as well as the concentrations of serotonin and dopamine in the different parts of the gastrointestinal tract, were studied in the snail Helix pomatia. The sensitivity of the spontaneous contractions of the alimentary tract to serotonin, dopamine, and FMRFamide was also tested. Serotonin-, tyrosine hydroxylase-, and FMRFamide-immunoreactive elements could be demonstrated in each part of the gastrointestinal tract, but they showed different innervation patterns. Serotonin- and tyrosine hydroxylase-immunoreactive elements were dominant in the submucosal layer, whereas FMRFamide-immunoreactive elements were dominant in both the mucosal and submucosal layers. Tyrosine hydroxylase-immunoreactive elements were confined to the longitudinal muscle trabeculae of submucosa, whereas serotonin-immunoreactive elements were distributed throughout the submucosal layer. No serotonin-immunoreactive cell bodies, but only fibers, could be detected in the gastrointestinal tract, and therefore they represent extrinsic elements. Tyrosine hydroxylase- and FMRFamide-immunoreactive cell bodies represent intrinsic elements of the tract. The occurrence and density of the serotonin- and tyrosine hydroxylase-immunoreactive elements showed significant differences in the different parts of the alimentary tract, in accordance with HPLC assays, which revealed a significant frontocaudal decrease in both the serotonin (from 2.11 to 1.21 pM/mg) and dopamine (from 3.28 to 0.52 pM/mg) contents of the different parts of the alimentary tract. Dopamine at 10-5 M concentration proved to be effective only on the longitudinal muscles by increasing the tone and frequency of contractions, but was ineffective on the circular muscles. Serotonin affected both the longitudinal and circular muscles. Serotonin at 10-5 M concentration decreased the tone and increased the frequency of low-amplitude contractions of the longitudinal muscles of the esophagus and the gizzard but increased both the tone and frequency of the crop. Serotonin at 10-9 M concentration slightly decreased the tone and blocked the contractions of the circular muscles in the crop but at 10-5 M concentration induced contractions of the circular muscles in the gizzard. FMRFamide at 10-6 M concentration decreased the tone and was shown to block the contractions of both the longitudinal and circular muscles.