Genome-wide association study for atopy and allergic rhinitis in a Singapore Chinese population

Allergic rhinitis (AR) is an atopic disease which affects about 600 million people worldwide and results from a complex interplay between genetic and environmental factors. However genetic association studies on known candidate genes yielded variable results. The aim of this study is to identify the genetic variants that influence predisposition towards allergic rhinitis in an ethnic Chinese population in Singapore using a genome-wide association study (GWAS) approach. A total of 4461 ethnic Chinese volunteers were recruited in Singapore and classified according to their allergic disease status. The GWAS included a discovery stage comparing 515 atopic cases (including 456 AR cases) and 486 non-allergic non-rhinitis (NANR) controls. The top SNPs were then validated in a replication cohort consisting of a separate 2323 atopic cases (including 676 AR cases) and 511 NANR controls. Two SNPs showed consistent association in both discovery and replication phases; MRPL4 SNP rs8111930 on 19q13.2 (OR = 0.69, P_combined = 4.46×10⁻⁰⁵) and BCAP SNP rs505010 on chromosome 10q24.1 (OR = 0.64, P_combined = 1.10×10⁻⁰⁴). In addition, we also replicated multiple associations within known candidates regions such as HLA-DQ and NPSR1 locus in the discovery phase. Our study suggests that MRPL4 and BCAP, key components of the HIF-1α and PI3K/Akt signaling pathways respectively, are two novel candidate genes for atopy and allergic rhinitis. Further study on these molecules and their signaling pathways would help in understanding of the pathogenesis of allergic rhinitis and identification of targets for new therapeutic intervention.     

Pharmacokinetic analysis of plasma curves obtained after i.v. injection of the PET radioligand [11C] raclopride provides a likely explanation for rapid radioligand metabolism

Positron emission tomography (PET) is an imaging technique that provides direct measurements of receptor binding in neurons. The present study was performed to find reasons for the common observation of rapid metabolism of receptor radioligands during time of a brain PET scan. To this aim, the 1-h phase during which imaging-data are acquired was evaluated by using a pharmacokinetic approach. The values of half-lives, volumes of distribution, and dilution calculated for a set of metabolite corrected plasma curves of D2-receptor radioligand [(11)C]raclopride (PETc) during 50 min after radioligand injection in tracer dose were compared with the reference values obtained from a set of plasma curves (REFc) during 30 h after i.v. infusion of unlabelled raclopride in pharmacological doses. We found that the half-life of PETc correspond to the distribution half-life of REFc. Accordingly, the distribution volume during the terminal phase of PETc (13.6 ± 10.8 L) was significantly lower than that during the terminal phase (82.2 ± 30.5 L) and at steady state (59.4 ± 20 L) for REFc, and the dilution of raclopride in body for PETc at 50 min was 38 L, whereas it was 1015 L for REFc at 30 h. The [(11)C]raclopride in plasma at 50 min was higher (10% of dose) than the value for unlabelled raclopride at 30 h (4%). We concluded that the kinetic behavior of the radiolabelled drug [(11)C]raclopride during the 1 h time of a PET corresponds to the distribution phase. The high percentage of [(11)C]raclopride in plasma during this phase is a likely reason for the observed rapid radioligand metabolism.     

In vitro CMV-infection model in fresh and glycerolized skin graft

Viral infections, especially cytomegalovirus (CMV), are a cause of death in burned patients. Aim of this study was to perform an in vitro CMV-infection model comparing fresh and glycerol-treated fibroblasts and keratinocytes. Cells were plated in plates for the two conditions. Each plate was set up with CMV dilutions. Immunofluorescence and real time PCR assays were performed. The assays were negative in both fresh and glycerolized keratinocytes. For fibroblasts, CMV-DNA was positive in both conditions and immunofluorescence test only in fresh cells. Glycerol at 85% confirms its strong virucidal effect as reported also for other viruses.     

Hypoxic regulation of angiotensin-converting enzyme 2 and Mas receptor in human CD34+ cells

CD34⁺ hematopoietic stem/progenitor cells (HSPCs) are vasculogenic and hypoxia is a strong stimulus for the vasoreparative functions of these cells. Angiotensin-converting enzyme 2 (ACE2)/angiotensin-(1–7)/Mas receptor (MasR) pathway stimulates vasoprotective functions of CD34⁺ cells. This study tested if ACE2 and MasR are involved in the hypoxic stimulation of CD34⁺ cells. Cells were isolated from circulating mononuclear cells derived from healthy subjects (n = 46) and were exposed to normoxia (20% O₂) or hypoxia (1% O₂). Luciferase reporter assays were carried out in cells transduced with lentivirus carrying ACE2- or MasR- or a scramble-3′-untranslated region gene with a firefly luciferase reporter. Expressions or activities of ACE, angiotensin receptor Type 1 (AT1R), ACE2, and MasR were determined. In vitro observations were verified in HSPCs derived from mice undergoing hindlimb ischemia (HLI). In vitro exposure to hypoxia-increased proliferation and migration of CD34⁺ cells in basal conditions or in response to vascular endothelial growth factor (VEGF) or stromal-derived factor 1α (SDF) compared with normoxia. Expression of ACE2 or MasR was increased relative to normoxia while ACE or AT1R expressions were unaltered. Luciferase activity was increased by hypoxia in cells transfected with the luciferase reporter plasmids coding for the ACE2- or MasR promoters relatively to the control. The effects of hypoxia were mimicked by VEGF or SDF under normoxia. Hypoxia-induced ADAM17-dependent shedding of functional ACE2 fragments. In mice undergoing HLI, increased expression/activity of ACE2 and MasR were observed in the circulating HSPCs. This study provides compelling evidence for the hypoxic upregulation of ACE2 and MasR in CD34⁺ cells, which likely contributes to vascular repair.     

Identification of potentially neurotoxic pyridinium metabolite in the urine of schizophrenic patients treated with haloperidol.

Evidence that the parkinsonian inducing agent MPTP is biotransformed to a pyridinium species that selectively destroys nigrostriatal neurons in humans and subhuman primates has prompted studies to evaluate the metabolic fate of the structurally related neuroleptic agent haloperidol. With the aid of a highly sophisticated atmospheric pressure ionspray HPLC/MS/MS assay, unambiguous evidence has been obtained for the presence of the haloperidol pyridinium species in extracts of urine obtained from haloperidol-treated patients and in extracts of NADPH-supplemented human liver microsomal incubation mixtures containing haloperidol. The potential significance of the formation of this putative neurotoxic pyridinium species is considered.     

Biofilter efficiency of <i>Eichhornia crassipes</i> in wastewater treatment of fish farming in Amazonia

Fish is a very important part of the human diet in Amazonia. Near the growing cities, fish populations and individual size have decreased over the past decades. Alternatives to traditional and industrial fishing arise, including fish farming. Strategies to minimize the impact of fish farms on the environment are needed to have a regular and healthy fish supply. This is to avoid a reduction of biodiversity, a depletion of natural resources, and/or the induction of significant changes in the structure and functioning of adjacent ecosystems. Very little research has been performed on management of effluents as to maintain the quality of water resources. The present study aimed at testing the efficiency of the Amazonian aquatic macrophyte Eichhornia crassipes as a biofilter for the treatment of effluents from fish farming. In three filtering treatments (50%, 75% and 100% plant cover) and a control (0%), physical and chemical properties of the water were measured and analyzed in a nursery with fish after passing the biofilter system, with a hydraulic retention time of 24 hours. The analyzed variables showed no significant differences (p>0.05) among the treatments with 50-100% cover, indicating that 50% cover would be enough for a good efficiency of the biofilter. All parameters were reduced after passage of the biofilter under the presence of E. crassipes: 73.7% for electrical conductivity, 15% for pH, 84.5% for turbidity, 86.8% for nitrite, 69% for total phosphorus, and 77.8% for orthophosphate. The concentrations of total nitrogen, nitrate and ammonium ions were not significantly changed (p>0.05). We conclude that E. crassipes is effective in improving the quality of effluents from fish farming, with less efficiency for nitrogen compounds. Our treatment system can be adopted by small and medium-sized farmers, aiming at a sustainable employment of the activity.     

Role of 14-3-3 proteins in the regulation of neutral trehalase in the yeast Saccharomyces cerevisiae

In higher eukaryotes, 14-3-3 proteins participate in numerous cellular processes, and carry out their function through a variety of different molecular mechanisms, including regulation of protein localization and enzyme activation. Here, it is shown that the two yeast 14-3-3 homologues, Bmh1p and Bmh2p, form a complex with neutral trehalase (Nth1p), an enzyme that is responsible for trehalose degradation and is required in a variety of stress conditions. In a purified in vitro system, either one of the two 14-3-3 yeast isoforms are necessary for complete activation of neutral trehalase (Nth1p) after phosphorylation by PKA. It is further demonstrated that Bmh1p and Bmh2p bind to the amino-terminal region of phosphorylated trehalase, thereby modulating its enzymatic activity. This work represents the first demonstration of enzyme activation mediated by 14-3-3 binding in yeast.     

Production and function of activin A in human dendritic cells

Activin A, a member of the transforming growth factor-beta superfamily, has a role in tissue repair and inflammation. In our previous studies, we identified by immunohistochemistry DC-SIGN(+) dendritic cells as a source of activin A in vivo. The present study was aimed at investigating activin A production by dendritic cells (DC) in vitro and its function. Here we demonstrate that monocyte-derived DC (Mo-DC) released abundant levels of activin A during the maturation process induced by TLR agonists, bacteria (B. henselae, S. thyphimurium), TNF and CD40L. Activin A was also induced in monocyte-derived Langerhans cells (LC) and in blood myeloid DC by LPS and/or CD40L stimulation, but not in blood plasmacytoid DC following stimulation with influenza virus. Activin A production by DC was selectively down-regulated by anti-inflammatory molecules such as dexamethasone or IL-10. Neutralization of endogenous activin A using its inhibitor follistatin, or the addition of exogenous activin A during LPS maturation did not affect Mo-DC maturation marker expression, cytokine release or allostimulatory function. However, Mo-DC matured with LPS in the presence of exogenous activin A displayed a higher FITC-dextran uptake, similar to that of immature DC. Moreover, activin A promoted monocyte differentiation to DC and reversed the inhibitory effects of IL-6 on DC differentiation of monocytes. These findings demonstrate that different subsets of DC release activin A, a cytokine that promotes DC generation, and affects the ability of mature DC to take up antigens (Ags).     

Dual inhibition of monoamine oxidase B and antagonism of the adenosine A(2A) receptor by (E,E)-8-(4-phenylbutadien-1-yl)caffeine analogues

The adenosine A(2A) receptor has emerged as an attractive target for the treatment of Parkinson's disease (PD). Evidence suggests that antagonists of the A(2A) receptor (A(2A) antagonists) may be neuroprotective and may help to alleviate the symptoms of PD. We have reported recently that several members of the (E)-8-styrylcaffeine class of A(2A) antagonists also are potent inhibitors of monoamine oxidase B (MAO-B). Since MAO-B inhibitors are known to possess anti-parkinsonian properties, dual-target-directed drugs that block both MAO-B and A(2A) receptors may have enhanced value in the management of PD. In an attempt to explore this concept further we have prepared three additional classes of C-8 substituted caffeinyl analogues. The 8-phenyl- and 8-benzylcaffeinyl analogues exhibited relatively weak MAO-B inhibition potencies while selected (E,E)-8-(4-phenylbutadien-1-yl)caffeinyl analogues were found to be exceptionally potent reversible MAO-B inhibitors with enzyme-inhibitor dissociation constants (K(i) values) ranging from 17 to 149 nM. Furthermore, these (E,E)-8-(4-phenylbutadien-1-yl)caffeines acted as potent A(2A) antagonists with K(i) values ranging from 59 to 153 nM. We conclude that the (E,E)-8-(4-phenylbutadien-1-yl)caffeines are a promising candidate class of dual-acting compounds.     

Predicting prostate biopsy outcome by findings at digital rectal examination, transrectal ultrasonography, PSA, PSA density and free-to-total PSA ratio in a population-based screening setting

The study offers a retrospective analysis of the positive predictive value (PPV) of several variables, i.e. digital rectal examination (DRE), transrectal ultrasonography (TRUS), PSA value, PSA density (PSAD), and free/total PSA ratio (F/T), for the histologic outcome of 179 prostate biopsies performed within a population-based screening trial. The ratio of spared benign biopsies to missed cancers (SBB/MC) if biopsy results had been decided on the basis of single variables was also evaluated. PPV was 82.9% for DRE, 56.3% for TRUS, 26.6% for PSA (cutoff > or =4 ng/mL), 47.4% for PSA (cutoff > or =10 ng/mL), 42.0% for PSAD (cutoff 0.15), 59.2% for PSAD (cutoff 0.20), 34.9% for F/T (cutoff 0.20) and 40.0% for F/T (cutoff 0.15). SBB/MC was 121/23 for DRE, 96/12 for TRUS, 11/10 for PSA (cutoff > or =4 ng/mL), 107/34 for PSA (cutoff > or =10 ng/mL), 87/23 for PSAD (cutoff 0.15), 109/26 for PSAD (cutoff 0.20), 45/8 for F/T (cutoff 0.20) and 70/14 for F/T (cutoff 0.15). Multivariate analysis of the association with biopsy outcome showed the highest odds ratio for TRUS (13.24, 95% CI=4.4-30.7), and considerably lower values for DRE (4.17, 95% CI=2.0-8-9), PSAD (cutoff 0.20: 3.24, 95% CI=-1.8-5.7) and F/T (cutoff <0.15: 3.16, 95% CI=1.7-1.8). None of the possible variable combinations was clinically useful: the highest PPV (83.3%) was obtained with a combination of suspicious DRE/TRUS, PSAD >0.20 and F/T <0.15, which nevertheless missed 20 of 52 cancers.