Site specific integration of FLP recombinase in BHK-21 cell line

A binary system for gene activation and site specific integration based on conditional recombination of transfected sequences mediated by FLP recombinase from yeast was implemented in mammalian cells. In several cell lines, FLP rapidly and precisely recombined copies of its specific target sequences to activate an otherwise silent beta-galactosidase reporter gene. Clones of marked cells were generated by excisional recombination within a chromosomally integrated copy of the silent reporters. These clones exhibited intense blue colour with X-Gal staining solution.     

Chiral synthesis of (2S,3S)-2-(2-morpholin-2-yl-2-phenylmethoxy)phenol

Resolution of (2RS,3RS)-2-[alpha-(2-methoxymethoxyphenoxy)phenylmethyl]morpholine, 11, with (+) mandelic acid led to the formation of (+)-(2S,3S)-2-[alpha-(2-methoxymethoxyphenoxy)phenyl methyl] morpholine (11a). Compound 11 was synthesized in seven steps from (2RS,3RS)-cinnamyl alcohol-2,3-epoxide (4), with an overall yield of 17%. Cleavage of the methoxymethyl group of the Fmoc derivative 12 with catalytic amounts of p-toluenesulfonic acid in methanol afforded (+)-(2S,3S)-2-(2-morpholin-2-yl-2-phenylmethoxy)phenol 2. The synthetic utility as well as the configuration of compound 2 has been demonstrated by converting (S,S)-2-(2-morpholin-2-yl-2-phenylmethoxy)phenol 2 to (2S,3S)-2-[alpha-(2-ethoxyphenoxy)phenylmethyl]morpholine (1) and (2S,3S)-2-(2-methoxyphenoxy) benzyl)morpholine (16), two potential norepinephrine reuptake inhibitors under clinical evaluation.     

Site-directed mutagenesis of the ferric uptake regulation gene of Escherichia coli

The 12 histidine and four cysteine residues of the Fur repressor of Escherichia coli were changed, respectively, to leucine and serine by site-directed mutagenesis of the fur gene. The affects of these mutations were measured in vivo by ligation of the mutated genes to a wild-type fur promoter followed by measurement of the ability of these plasmids to regulate expression of a lacZ fusion in the aerobactin operon. In vitro affects were assayed by insertion of the mutated genes in the expression vector pMON2064 attended by isolation of the altered Fur proteins and appraisal of their capacity to bind to operator DNA. The results suggest that cysteine residues at positions 92 and 95 are important for the activity of the Fur protein.     

Synthesis and biological activities of some new dibenzopyranones and dibenzopyrans: search for potential oestrogen receptor agonists and antagonists

Continuing our search for newer oestrogen agonists or antagonists and extending our work on the exploration of benzopyran related compounds, some new tricyclic molecules bridged between the active molecules of 3,4-diaryl chroman and 2,3-diaryl benzopyrans have been synthesised. Structural modifications at different positions with elements known to impart agonist or antagonist activities have been carried out to prepare the desired molecules. The target compounds were screened for their anti-osteoporotic (agonist) and anti-uterotrophic (antagonist) activities and were found to be moderately active.     

Synthesis of [O-methyl-11C]1-(2-chlorophenyl)-5-(4-methoxyphenyl)-4-methyl-1H-pyrazole-3-carboxylic acid piperidin-1-ylamide: a potential PET ligand for CB1 receptors

Synthesis and in vitro evaluation of [O-methyl-(11)C]1-(2-chlorophenyl)-5-(4-methoxyphenyl)-4-methyl-1H-pyrazole-3-carboxylic acid piperidin-1-ylamide ([(11)C]-1), a potential imaging agent for CB(1) receptors using PET is described. 1-(2-Chlorophenyl)-5-(4-hydroxyphenyl)-4-methyl-1H-pyrazole-3-carboxylic acid piperidin-1-ylamide (5), the precursor for radiolabeling, was synthesized from 4-OTBDPS-propiophenone (2) in five steps with 30% overall yield. The reaction of alcohol 5 with [(11)C]MeOTf at 60 degrees C afforded [(11)C]-1 with an average radiochemical yield of 14.5% (EOS) and >2000 Ci/mmol specific activity. The radiotracer was found to selectively label CB(1) receptors in slide-mounted sections of postmortem human brain containing prefrontal cortex as demonstrated by in vitro autoradiography using phosphor imaging.     

Differential requirement for cell fusion and virion formation in the pathogenesis of varicella-zoster virus infection in skin and T cells

The protein product of varicella-zoster virus (VZV) ORF47 is a serine/threonine protein kinase and tegument component. Evaluation of two recombinants of the Oka strain, rOka47DeltaC, with a C-terminal truncation of ORF47, and rOka47D-N, with a point mutation in the conserved kinase motif, showed that ORF47 kinase function was necessary for optimal VZV replication in human skin xenografts in SCID mice but not in cultured cells. We now demonstrate that rOka47DeltaC and rOka47D-N mutants do not infect human T-cell xenografts. Differences in the growth of kinase-defective ORF47 mutants allowed an examination of requirements for VZV pathogenesis in skin and T cells in vivo. Although virion assembly was reduced and no virion transport to cell surfaces was observed, epidermal cell fusion persisted, and VZV polykaryocytes were generated by rOka47DeltaC and rOka47D-N in skin. Virion assembly was also impaired in vitro, but VZV-induced cell fusion continued to cause syncytia in cultured cells infected with rOka47DeltaC or rOka47D-N. Intracellular trafficking of envelope glycoprotein E and the ORF47 and IE62 proteins, components of the tegument, was aberrant without ORF47 kinase activity. In summary, normal VZV virion assembly appears to require ORF47 kinase function. Cell fusion was induced by ORF47 mutants in skin, and cell-cell spread occurred even though virion formation was deficient. VZV-infected T cells do not undergo cell fusion, and impaired virion assembly by ORF47 mutants was associated with a complete elimination of T-cell infectivity. These observations suggest a differential requirement for cell fusion and virion formation in the pathogenesis of VZV infection in skin and T cells.     

Low fat dietary intervention with omega-3 fatty acid supplementation in multiple sclerosis patients

OBJECTIVES: To determine whether a low fat diet supplemented with omega-3 positively affects quality of life (QOL) in relapsing-remitting MS (RRMS) patients. In this 1-year long double-blind, randomized trial, patients were randomized to two dietary interventions: the "Fish Oil" (FO) group received a low fat diet (15% fat) with omega-3 FOs and the "Olive Oil" (OO) group received the AHA Step I diet (fat 30%) with OO supplements. The primary outcome measure was the Physical Components Summary Scale (PCS) of the Short Health Status Questionnaire (SF-36). Additional measures using MS specific QOL questionnaires, neurological status and relapse rate were obtained. RESULTS: 31 RRMS patients were enrolled, with mean follow up over 11 +/- SD 2.9 months. Clinical benefits favoring the FO group were observed on PCS/SF-36 (P = 0.050) and MHI (P = 0.050) at 6 months. Reduced fatigue was seen on the OO diet at 6 months (P = 0.035). The relapse rate decreased in both groups relative to the rates during the 1 year preceding the study: mean change in relapse rate in the FO group: -0.79 +/- SD 1.12 relapses/year (P = 0.021) vs. -0.69 +/- SD 1.11 (P = 0.044) in the OO group. This study suggests that a low fat diet supplemented with omega-3 PUFA can have moderate benefits in RRMS patients on concurrent disease modifying therapies.     

A general method for the synthesis of aryl [11C]methylsulfones: potential PET probes for imaging cyclooxygenase-2 expression

A general one-pot method has been developed for the conversion of an aryl thiol moiety masked as the butyrate ester to the corresponding 11C-labeled methylsulfone group. The potential of this methodology has been demonstrated by the successful radiosynthesis of carbon-11 analogues of several highly selective cyclooxygenase-2 (COX-2) inhibitors such as Rofecoxib, Etoricoxib, and 3-(4-methylsulfonylphenyl)-4-phenyl-5-trifluoromethyl isoxazole in high yield. The chemical and radiochemical purities obtained for the 11C-labeled COX-2 inhibitors are >99% with a specific activity >1000 Ci/mmol.     

Dantrolene stabilizes domain interactions within the ryanodine receptor

Interdomain interactions between N-terminal and central domains serving as a "domain switch" are believed to be essential to the functional regulation of the skeletal muscle ryanodine receptor-1 Ca(2+) channel. Mutational destabilization of the domain switch in malignant hyperthermia (MH), a genetic sensitivity to volatile anesthetics, causes functional instability of the channel. Dantrolene, a drug used to treat MH, binds to a region within this proposed domain switch. To explore its mechanism of action, the effect of dantrolene on MH-like channel activation by the synthetic domain peptide DP4 or anti-DP4 antibody was examined. A fluorescence probe, methylcoumarin acetate, was covalently attached to the domain switch using DP4 as a delivery vehicle. The magnitude of domain unzipping was determined from the accessibility of methylcoumarin acetate to a macromolecular fluorescence quencher. The Stern-Volmer quenching constant (K(Q)) increased with the addition of DP4 or anti-DP4 antibody. This increase was reversed by dantrolene at both 37 and 22 degrees C and was unaffected by calmodulin. [(3)H]Ryanodine binding to the sarcoplasmic reticulum and activation of sarcoplasmic reticulum Ca(2+) release, both measures of channel activation, were enhanced by DP4. These activities were inhibited by dantrolene at 37 degrees C, yet required the presence of calmodulin at 22 degrees C. These results suggest that the mechanism of action of dantrolene involves stabilization of domain-domain interactions within the domain switch, preventing domain unzipping-induced channel dysfunction. We suggest that temperature and calmodulin primarily affect the coupling between the domain switch and the downstream mechanism of regulation of Ca(2+) channel opening rather than the domain switch itself.