Abstract: The voltage-gated calcium channel is composed of a pore-forming alpha(1) subunit and several regulatory subunits: alpha(2)delta, beta, and gamma. We report here the identification of a novel alpha(2)delta subunit, alpha(2)delta-4, from the expressed sequence tag database followed by its cloning and characterization. The novel alpha(2)delta-4 subunit gene contains 39 exons spanning about 130 kilobases and is co-localized with the CHCNA1C gene (alpha(1C) subunit) on human chromosome 12p13.3. Alternative splicing of the alpha(2)delta-4 gene gives rise to four potential variants, a through d. The open reading frame of human alpha(2)delta-4a is composed of 3363 base pairs encoding a protein with 1120 residues and a calculated molecular mass of 126 kDa. The alpha(2)delta-4a subunit shares 30, 32, and 61% identity with the human calcium channel alpha(2)delta-1, alpha(2)delta-2, and alpha(2)delta-3 subunits, respectively. Primary sequence comparison suggests that alpha(2)delta-4 lacks the gabapentin binding motifs characterized for alpha(2)delta-1 and alpha(2)delta-2; this was confirmed by a [(3)H]gabapentin-binding assay. In human embryonic kidney 293 cells, the alpha(2)delta-4 subunit associated with Ca(V)1.2 and beta(3) subunits and significantly increased Ca(V)1.2/beta(3)-mediated Ca(2+) influx. Immunohistochemical study revealed that the alpha(2)delta-4 subunit has limited distribution in special cell types of the pituitary, adrenal gland, colon, and fetal liver. Whether the alpha(2)delta-4 subunit plays a distinct physiological role in select endocrine tissues remains to be demonstrated.

Abstract: The cloning of novel G protein-coupled receptors and the search for their natural ligands, a process called reverse pharmacology, is an excellent opportunity to discover novel hormones and neurotransmitters. Based on a degenerate primer approach we have cloned a G protein-coupled receptor whose mRNA expression profile indicates highest expression in the dorsal root ganglia, specifically in the subset of small neurons, suggesting a role in nociception. In addition, moderate expression was found in lung, hypothalamus, peripheral blood leukocytes, and ovaries. Guided by a receptor-activation bioassay, we identified adenine as the endogenous ligand, which activated the receptor potently and with high structural stringency. Therefore, we propose to name this receptor as the adenine receptor. Hormonal functions have already been demonstrated for adenine derivatives like 6-benzylaminopurine in plants and 1-methyladenine in lower animals. Here, we demonstrate that adenine functions as a signaling molecule in mammals. This finding adds a third family besides P1 and P2 receptors to the class of purinergic receptors.

Abstract: Methylisocyanoacetate undergoes a 2 + 3 cycloaddition with α,β-unsaturated nitriles to provide a regioselective synthesis of 2-substituted 3,4-diaryl pyrroles. The ease of preparation of α,β-unsaturated nitriles allows the rapid synthesis of pyrroles with varied substituents. Using this method, a key intermediate (1) for the synthesis of the marine natural products lukianol A, lamellarin O, and lamellarin Q was prepared in two steps. A total synthesis of ningalin B (11) was also accomplished utilizing this methodology.

Abstract: Galantamine is a competitive acetylcholine esterase inhibitor with a beneficial therapeutic effect in patients with Alzheimer9s disease. The metabolism and excretion of orally administered3H-labeled galantamine was investigated in rats and dogs at a dose of 2.5 mg base-Eq/kg body weight and in humans at a dose of 4 mg base-Eq. Both poor and extensive metabolizers of CYP2D6 were included in the human study. Urine, feces, and plasma samples were collected for up to 96 h (rats) or 168 h (dogs and humans) after dosing. The radioactivity of the samples and the concentrations of galantamine and its major metabolites were analyzed. In all species, galantamine and its metabolites were predominantly excreted in the urine (from 60% in male rats to 93% in humans). Excretion of radioactivity was rapid and nearly complete at 96 h after dosing in all species. Major metabolic pathways were glucuronidation,O-demethylation, N-demethylation,N-oxidation, and epimerization. All metabolic pathways observed in humans occurred in at least one animal species. In extensive metabolizers for CYP2D6, urinary metabolites resulting fromO-demethylation represented 33.2% of the dose compared with 5.2% in poor metabolizers, which showed correspondingly higher urinary excretion of unchanged galantamine and itsN-oxide. The glucuronide ofO-desmethyl-galantamine represented up to 19% of the plasma radioactivity in extensive metabolizers but could not be detected in poor metabolizers. Nonvolatile radioactivity and unchanged galantamine plasma kinetics were similar for poor and extensive metabolizers. Genetic polymorphism in the expression of CYP2D6 is not expected to affect the pharmacodynamics of galantamine.

Abstract: This study tested whether levofloxacin, at a new high dose of 750 mg, was effective for the treatment of complicated skin and skin-structure infections (SSSIs). Patients with complicated SSSIs (n=399) were randomly assigned in a ratio of 1:1 to 2 treatment arms: levofloxacin (750 mg given once per day intravenously [iv], orally, or iv/orally) or ticarcillin-clavulanate (TC; 3.1 g given iv every 4-6 hours) followed, at the investigator's discretion, by amoxicillin-clavulanate (AC; 875 mg given orally every 12 hours). In the clinically evaluable population, therapeutic equivalence was demonstrated between the levofloxacin and TC/AC regimens (success rates of 84.1% and 80.3%, respectively). In the microbiologically evaluable population, the overall rate of eradication was 83.7% in the levofloxacin treatment group and 71.4% in the TC/AC treatment group (95% confidence interval, -24.3 to -0.2). Both levofloxacin and TC/AC were well tolerated. These data demonstrate that levofloxacin (750 mg once per day) is safe and at least as effective as TC/AC for complicated SSSIs.

Abstract: Background. Fluoroquinolones (FQs) have been infrequently used in children, largely because of concern that these agents can cause lesions of the cartilage in juvenile animals. However, the relevance of this laboratory observation to children treated with FQs is unknown. A retrospective, observational study was conducted to assess the incidence and relative risk of tendon or joint disorders (TJDs) that occur after use of selected FQs compared with azithromycin (AZ), a drug with no known effect on cartilage or tendons in humans or animals. Methods. An automated database was searched to identify patients younger than 19 years who had been prescribed ofloxacin (OFX), levofloxacin, ciprofloxacin (CPX), or AZ. Potential cases of TJD occurring within 60 days of a prescription of one of the study drugs were identified based on assignment of a claims diagnosis consistent with a TJD within this period. Verified cases were identified by a blinded review of abstracts of medical records from subjects identified as potential cases. Results. The incidence of verified TJD was 0.82% for OFX (13 of 1593) and CPX (37 of 4531) and was 0.78% for AZ (118 of 15 073). The relative risk of TJD for OFX and CPX compared with AZ was 1.04 (95% confidence interval, 0.55 to 1.84) and 1.04 (95% confidence interval, 0.72 to 1.51), respectively. The distributions of claims diagnoses and time to onset of TJD were comparable for all groups. The most frequently reported category of TJD involved the joint followed by tendon, cartilage and gait disorder. Conclusions. In this observational study involving more than 6000 FQ-treated children, the incidence of TJD associated with selected FQ use in children was <1% and was comparable with that of the reference group, children treated with AZ.

Abstract: All-trans-retinoic acid is a potent inhibitor of cell proliferation and inducer of differentiation. However, the clinical use of all-trans-retinoic acid in the treatment of cancer is significantly hampered by its toxicity and the prompt emergence of resistance, believed to be caused by increased all-trans-retinoic acid metabolism. Inhibitors of all-trans-retinoic acid metabolism may therefore prove valuable in the treatment of cancer. In this study, we characterize R116010 as a new anticancer drug that is a potent inhibitor of all-trans-retinoic acid metabolism. In vitro, R116010 potently inhibits all-trans-retinoic acid metabolism in intact T47D cells with an IC50-value of 8.7 nM. In addition, R116010 is a selective inhibitor as indicated by its inhibition profile for several other cytochrome P450-mediated reactions. In T47D cell proliferation assays, R116010 by itself has no effect on cell proliferation. However, in combination with all-trans-retinoic acid, R116010 enhances the all-trans-retinoic acid-mediated antiproliferative activity in a concentration-dependent manner. In vivo, the growth of murine oestrogen-independent TA3-Ha mammary tumours is significantly inhibited by R116010 at doses as low as 0.16 mg kg−1. In conclusion, R116010 is a highly potent and selective inhibitor of all-trans-retinoic acid metabolism, which is able to enhance the biological activity of all-trans-retinoic acid, thereby exhibiting antitumour activity. R116010 represents a novel and promising anticancer drug with an unique mechanism of action.

Abstract: beta-Lactamases have been critical factors for the selection and development of beta-lactam-containing antibacterial agents for almost 60 years. New agents under investigation continue to be evaluated based on their interactions with beta-lactamases. Oral carbapenems, penems and antimethicillin-resistant Staphylococcus aureus cephalosporins are all being selected for development, in part, because of their stability to hydrolysis by the beta-lactamases of their target organisms. beta-Lactamase inhibitors must selectively inhibit the major beta-lactamase groups appearing in current clinical isolates. For all agents, the multiplicity of beta-lactamases in single organisms or in mixed infections poses a new set of challenges requiring agents that can respond to enzymes with varying functional characteristics.

Abstract: The Mouse Lymphoma Assay (MLA) Workgroup of the International Workshop on Genotoxicity Test Procedures held a second harmonization meeting just prior to the U.S. Environmental Mutagen Society Meeting in New Orleans, LA, in April 2000. The discussion focused on several important aspects of the MLA, including: 1) cytotoxicity measures and their determination, 2) use of a 24-hr treatment, 3) the ability of the assay to detect aneugens, and 4) concentration selection. Prior to the meeting the group developed Microsoft Excel Workbooks for data entry. Ten laboratories entered their data into the workbooks (primarily as coded chemicals). The Excel Workbooks were used to facilitate data analysis by generating an extensive set of graphs that were evaluated by the meeting participants. Based on the Workgroup's previous agreement that a single cytotoxicity measure should be established for both the microwell and soft agar versions of the assay, the Workgroup analyzed the submitted data and unanimously agreed that the relative total growth (RTG) should be used as the cytotoxicity measure for concentration selection and data evaluation. The Workgroup also agreed that the various cytotoxicity measures should be calculated using the same methods regardless of whether the soft agar or microwell version of the assay was used. In the absence of sufficient data to make a definitive determination, the Workgroup continued to endorse the International Committee on Harmonization recommendation for the use of 24-hr treatment and made some specific 24-hr treatment protocol recommendations. The Workgroup recognized the ability of the MLA to detect at least some aneugens and also developed general guidance and requirements for appropriate concentration selection.

Abstract: The p38 MAP kinase is thought to be involved in a variety of inflammatory and immunological disorders such as rheumatoid arthritis. The pyridinylimidazole class of compounds was the first to potently inhibit this kinase. Since the original reports of their efficacy, they have become the most widely studied series of inhibitors of this kinase. This framework has served as a starting point for further synthetic work and several compounds have entered clinical trials. These compounds have also been utilized to elucidate the role of p38 kinase in the immune system, and more recently have been used to examine the role of this kinase in central nervous system disorders.

Abstract: The serine protease cathepsin G (EC 3.4.21.20; Cat G), which is stored in the azurophilic granules of neutrophils (polymorphonuclear leukocytes) and released on degranulation, has been implicated in various pathological conditions associated with inflammation. By employing high-throughput screening, we identified β-ketophosphonic acid 1 as a moderate inhibitor of Cat G (IC50 = 4.1 μM). We were fortunate to obtain a cocrystal of 1 with Cat G and solve its structure by X-ray crystallography (3.5 A). Structural details from the X-ray analysis of 1·Cat G served as a platform for optimization of this lead compound by structure-based drug design. With the aid of molecular modeling, substituents were attached to the 3-position of the 2-naphthyl ring of 1, which occupies the S1 pocket of Cat G, to provide an extension into the hydrophobic S3 region. Thus, we arrived at analogue 7 with an 80-fold potency improvement over 1 (IC50 = 53 nM). From these results, it is evident that the β-ketophosphonic acid unit can fo...

Abstract: Elements of informed consent for pharmacogenetic research; perspective of the pharmacogenetics working group

Abstract: The standard method for preparing carboxylic acid hydrazides is hydrazinolysis of esters in alcoholic solutions. However, when applied to α,β-unsaturated esters, the main product typically is the pyrazolidinone resulting from an undesired Michael-type cyclization. Other alternative methodologies reported for direct preparation of hydrazides from acids are inefficient. We developed an efficient and general process, involving preforming activated esters and/or amides followed by reaction with hydrazine, for the preparation of hydrazides including those of α,β-unsaturated acids. This process gives the desired hydrazides in excellent yield and purity under mild conditions.