Validation of LC-MS/MS methods for quantitative analysis of kynurenine pathway metabolites in human plasma and cerebrospinal fluid.

Dysregulation of the kynurenine metabolic pathway has been reported in several neurological conditions. Sensitive and selective LC-MS/MS methods have been validated for six kynurenine pathway metabolites in human cerebrospinal fluid and plasma. For each matrix, we validated three methods - one for the simultaneous determination of kynurenine, kynurenic acid, anthranilic acid and 3-hydroxy-kynurenine (four-analyte assay), one for quinolinic acid and one for tryptophan - using stable-isotopically labeled internal standards.

A sensitive LC-MS/MS method for simultaneous quantification of ulotaront and its N-desmethyl metabolite in human plasma and application to a clinical study.

Ulotaront (SEP-363856) is a novel non-D2-receptor-binding agent under development for the treatment of patients with schizophrenia. A highly sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method with lower limit of quantitation of 0.0200 ng/mL (i.

Use of venoarterial extracorporeal membrane oxygenation in fulminant chagasic myocarditis as a bridge to heart transplant.

A 17-year-old Brazilian male presented with progressive dyspnea for 15 days, worsening in the last 24 hours, and was admitted in respiratory failure and cardiogenic shock, with multiple organ dysfunctions. Echocardiography showed a left ventricle ejection fraction of 11%, severe diffuse hypokinesia, and a systolic pulmonary artery pressure of 50mmHg, resulting in the need for hemodynamic support with dobutamine (20mcg/kg/min) and noradrenaline (1.7mcg/kg/min).

Determination of carboplatin in human plasma using HybridSPE-precipitation along with liquid chromatography-tandem mass spectrometry.

The main purpose of this study was to develop and validate a rapid, specific, sensitive, and reliable LC-MS/MS-based bioanalytical method for the determination of carboplatin in human plasma. The optimal chromatographic behavior of carboplatin was achieved on a Biobasic SCX column (50 mm × 2.1 mm, 5 μm) using ion exchange chromatography.

Optimization and utilization of the SureFire phospho-STAT5 assay for a cell-based screening campaign.

The family of signal transducers and activators of transcription (STATs) consists of seven transcription factors that respond to a variety of cytokines, hormones, and growth factors. STATs are activated by tyrosine phosphorylation, which results in their dimerization and translocation into the nucleus where they exert their effect on transcription of regulated target genes. The phosphorylation of STATs is mediated mainly by Janus kinases (JAKs).

The effect of folate deficiency on the hprt mutational spectrum in Chinese hamster ovary cells treated with monofunctional alkylating agents.

Folic acid deficiency acts synergistically with alkylating agents to increase DNA strand breaks and mutant frequency at the hprt locus in Chinese hamster ovary (CHO) cells. To elucidate the mechanism of this synergy, molecular analyses of hprt mutants were performed. Recently, our laboratory showed that folate deficiency increased the percentage of clones with intragenic deletions after exposure to ethyl methanesulfonate (EMS) but not N-nitroso-N-ethylurea (ENU) compared to clones recovered from folate replete medium.

Nutritional folate status influences the efficacy and toxicity of chemotherapy in rats.

The effect of folate status on the efficacy and toxicity of chemotherapy was investigated in weanling Fischer 344 rats maintained on diets of varying folate content or supplemented with daily injections of folic acid, 50 mg/kg, for 6 to 7 weeks. MADB106 rat mammary tumor growth rate was the same in folate replete and supplemented rats, but retarded in the low folate groups. The tumor growth inhibitions in low folate, replete and high folate rats treated with cyclophosphamide were: 53%, 98%, and 97% (P = .

Nutritional folate deficiency augments the in vivo mutagenic and lymphocytotoxic activities of alkylating agents.

To investigate the interaction of folate deficiency and alkylating agents in vivo, weanling Fischer 344 rats were maintained for 5 weeks on a folate replete, moderately folate deficient, or a severely folate deficient diet. Mutant frequencies at the HPRT locus in splenic lymphocytes were 1.2+/-0.

Effect of folate deficiency on mutations at the hprt locus in Chinese hamster ovary cells exposed to monofunctional alkylating agents.

Multiplex PCR amplification of hprt exons from 113 Chinese hamster ovary cell clones selected for resistance to 6-thioguanine was performed to investigate the molecular basis for the synergistic mutagenic effects of nutritional folic acid deficiency and alkylating agents. In cells treated with ethyl methanesulfonate, intragenic deletions were detected in 9 of 46 (19.6%) clones derived from folate-deficient cells, but in none of 16 mutants grown in folate-replete medium.

Amplification of antibody production by phosphorothioate oligodeoxynucleotides.

A phosphorothioate oligodeoxynucleotide that is complementary (antisense) to the initiation region of the rev gene of HIV-1 causes hypergammaglobulinemia and splenomegaly in mice, and it induces B cell proliferation and differentiation in mouse spleen mononuclear cells (SMNCs) and human peripheral blood mononuclear cells in vitro. The current studies were performed to investigate the specificity of these immunomodulatory effects. Both the sense and antisense rev oligomers stimulated tritiated thymidine incorporation and secretion of immunoglobulin M (IgM) and immunoglobulin G (IgG) by mouse SMNCs in a concentration-dependent fashion, but the antisense oligomer produced greater immune effects.

Efficacy evaluations on five chlorhexidine teat dip formulations.

Three developmental postmilking teat dip formulations containing chlorhexidine digluconate were evaluated against Staphylococcus aureus and Streptococcus agalactiae in sequential experimental exposure trials. Two additional commercial chlorhexidine digluconate teat dip products were evaluated in natural exposure trials. Under conditions of experimental challenge, the developmental formulations were efficacious against Staph.