Evaluation of a Benzodiazepine Immunoassay for Urine Drug Testing in Clinical Specimens.

Background: Benzodiazepines are commonly prescribed medications frequently linked to instances of abuse and overdose. Historically, FDA-cleared benzodiazepine urine immunoassays cross-react poorly with glucuronidated benzodiazepine metabolites, leading to false negatives. Clinical laboratories have addressed this deficiency by creating laboratory-developed tests (LDTs) that incorporate a beta-glucuronidase hydrolysis step to increase the clinical sensitivity of these assays.

Evaluating the performance of the Roche FEN2 fentanyl immunoassay and its clinical implementation: The role of LDT-based mass spectrometry testing.

Introduction: While laboratory-developed tests (LDTs) using liquid chromatography tandem mass spectrometry (LC-MS/MS) are widely employed to support the development of FDA-cleared drug immunoassays, their significance in the clinical implementation and evaluation of such assays is often overlooked. This paper reports on the important role of LC-MS/MS LDTs in demonstrating improved performance of the Roche FEN2 fentanyl immunoassay compared with the Thermo DRI fentanyl immunoassay.

Methods: The FEN2 assay was implemented according to the manufacturer's instructions and its performance was compared to the existing DRI assay using LC-MS/MS as a reference.

Comparison of two highly sensitive benzodiazepine immunoassay lab developed tests for urine drug testing in clinical specimens.

Background: The VALID Act is a legislative effort that, if enacted, would alter the regulatory requirements of laboratory developed tests (LDTs) used for clinical testing in the United States. Benzodiazepines, which are primarily excreted into urine as glucuronidated metabolites such as lorazepam, cross-react poorly with FDA-cleared immunoassays, leading to false-negatives. This shortfall can be addressed with LDTs created by adding glucuronidase to the immunoassay reagents producing "high sensitivity" assays that detect glucuronidated metabolites.

SARS-CoV-2 Serology Status Detected by Commercialized Platforms Distinguishes Previous Infection and Vaccination Adaptive Immune Responses.

Background: The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has infected over 110 million individuals and led to 2.5 million deaths worldwide. As more individuals are vaccinated, the clinical performance and utility of SARS-CoV-2 serology platforms needs to be evaluated.

SARS-CoV-2 Serology Status Detected by Commercialized Platforms Distinguishes Previous Infection and Vaccination Adaptive Immune Responses.

Background: The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has infected over 110 million individuals and led to 2.5 million deaths worldwide. As more individuals are vaccinated, the clinical performance and utility of SARS-CoV-2 serology platforms needs to be evaluated.

Commercial Serology Assays Predict Neutralization Activity against SARS-CoV-2.

Background: It is unknown whether a positive serology result correlates with protective immunity against SARS-CoV-2. There are also concerns regarding the low positive predictive value of SARS-CoV-2 serology tests, especially when testing populations with low disease prevalence.

Methods: A neutralization assay was validated in a set of PCR-confirmed positive specimens and in a negative cohort.

Multi-Platform Comparison of SARS-CoV-2 Serology Assays for the Detection of COVID-19.

Background: COVID-19 is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a novel beta-coronavirus that is responsible for the 2019 coronavirus pandemic. Acute infections should be diagnosed by polymerase chain reaction (PCR) based tests, but serology tests can demonstrate previous exposure to the virus.

Methods: We compared the performance of the Diazyme, Roche, and Abbott SARS-CoV-2 serology assays using 179 negative participants to determine negative percentage agreement (NPA) and in 60 SARS-CoV-2 PCR-confirmed positive patients to determine positive percentage agreement (PPA) at 3 different time frames following a positive SARS-CoV-2 PCR result.

Longitudinal Monitoring of SARS-CoV-2 IgM and IgG Seropositivity to Detect COVID-19.

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a novel beta-coronavirus that has recently emerged as the cause of the 2019 coronavirus pandemic (COVID-19). Polymerase chain reaction (PCR) based tests are optimal and recommended for the diagnosis of an acute SARS-CoV-2 infection. Serology tests for viral antibodies provide an important tool to diagnose previous exposure to the virus.

A Dilution Method to Mitigate Biotin Interference in Cardiac Troponin T Testing.

Background: Oral biotin supplementation is known to interfere with biotin-streptavidin-based immunoassays, including Roche's fifth-generation cardiac troponin T (cTnT) assay, which plays a critical role in the diagnosis of myocardial infarction (MI). The utility of dilution, a quick and easy method to detect and remove interferences, has not been published for biotin interference.

Methods: Concentrations of cTnT were measured in pooled serum from clinical samples.

MGST1, a GSH transferase/peroxidase essential for development and hematopoietic stem cell differentiation.

We show for the first time that, in contrast to other glutathione transferases and peroxidases, deletion of microsomal glutathione transferase 1 (MGST1) in mice is embryonic lethal. To elucidate why, we used zebrafish development as a model system and found that knockdown of MGST1 produced impaired hematopoiesis. We show that MGST1 is expressed early during zebrafish development and plays an important role in hematopoiesis.

Hydroxyurea derivatives of irofulven with improved antitumor efficacy.

Irofulven is a semi-synthetic derivative of Illudin S, a toxic sesquiterpene isolated from the mushroom Omphalotus illudens. Irofulven has displayed significant antitumor activity in various clinical trials but displayed a limited therapeutic index. A new derivative of irofulven was prepared by reacting hydroxyurea with irofulven under acidic conditions.

Absence of MGST1 mRNA and protein expression in human neuroblastoma cell lines and primary tissue.

A recent study identified a haplotype on a small region of chromosome 12, between markers D12S1725 and D12S1596, shared by all patients with familial neuroblastoma (NB). We previously localized the human MGST1 gene, whose gene product protects against oxidative stress, to this very same chromosomal region (12p112.1-p13.

Structure-activity studies of urea, carbamate, and sulfonamide derivatives of acylfulvene.

Illudin S and M (1, 2) are highly toxic sesquiterpenes found in the basidiomycete Omphalotus illudens. Illudins have a low therapeutic index, but acylfulvene derivatives display potent in vivo antitumor activity against a variety of multidrug resistant tumors. The lead acylfulvene (4), irofulven (5), in a randomized phase IIB clinical trial significantly increased overall survival in patients with metastatic hormone-refractory prostate cancer who failed prior treatment with two different standard chemotherapeutic regimens.

Stability of levothyroxine sodium 0.4 microg/mL in 0.9% sodium chloride injection.

Context: Intravenous levothyroxine therapy decreases vasopressor requirements and prevents cardiovascular collapse in hemodynamically unstable patients eligible for organ donation. The stability of levothyroxine when used in this manner is unknown.

Objective: To determine the stability of levothyroxine solution for intravenous use at a concentration of 0.

Synergy of irofulven in combination with other DNA damaging agents: synergistic interaction with altretamine, alkylating, and platinum-derived agents in the MV522 lung tumor model.

Purpose: Irofulven (MGI 114, NSC 683863) is a semisynthetic derivative of illudin S, a natural product present in the Omphalotus illudins (Jack O'Lantern) mushroom. This novel agent produces DNA damage, that in contrast to other agents, is predominately ignored by the global genome repair pathway of the nucleotide excision repair (NER)(2) system. The aim of this study was to determine the antitumor activity of irofulven when administered in combination with 44 different DNA damaging agents, whose damage is in general detected and repaired by the genome repair pathway.

Synergy of Irofulven in combination with various anti-metabolites, enzyme inhibitors, and miscellaneous agents in MV522 lung carcinoma cells: marked interaction with gemcitabine and 5-fluorouracil.

The novel agent Irofulven (HMAF, NSC 683863) has demonstrated significant antitumor activity against solid tumors in various xenograft models and human clinical trials. The antitumor potential of combining irofulven with 72 different anti-metabolite, enzyme inhibiting, and miscellaneous agents was investigated in this study. The human lung carcinoma MV522 cell line and its corresponding xenograft model were used to evaluate the activity of irofulven in combination with these different agents.

Disruption of the ugt1 locus in mice resembles human Crigler-Najjar type I disease.

The 9 UDP-glucuronosyltranferases (UGTs) encoded by the UGT1 locus in humans are key enzymes in the metabolism of most drugs as well as endogenous substances such as bile acids, fatty acids, steroids, hormones, neurotransmitters, and bilirubin. Severe unconjugated hyperbilirubinemia in humans that suffer from Crigler-Najjar type I disease results from lesions in the UGT1A1 gene and is often fatal. To examine the physiological importance of the Ugt1 locus in mice, this locus was rendered non-functional by interrupting exon 4 to create Ugt1(-/-) mice.

Synthesis and antitumor activity of amine analogs of irofulven.

Acylfulvenes, a class of semisynthetic analogs of Illudin S, show high toxicity toward prostate cancer cells. Here we probe the effect of changes in hydrophilic character of the analogs.

Phase I/II study of continuous-infusion troxacitabine in refractory acute myeloid leukemia.

Purpose: Troxacitabine is a non-natural nucleoside analog with unique structural and metabolic features. Bolus intravenous (IV) troxacitabine regimens have shown significant activity in patients with refractory acute myeloid leukemia (AML) and preclinical data suggest that administration via continuous infusion may result in enhanced antitumor activity.

Patients And Methods: Patients with refractory AML initially received troxacitabine 10.

Structural organization of the murine microsomal glutathione S-transferase gene (MGST1) from the 129/SvJ strain: identification of the promoter region and a comprehensive examination of tissue expression.

The structure and regulation of the murine microsomal glutathione transferase gene (MGST1) from the 129/SvJ strain is described and demonstrates considerable difference in nucleotide sequence and consequently in restriction enzyme sites as compared to other mouse strains. A comparison of the amino acid sequence for MGST1 revealed one difference in exon 2 between the 129/SvJ strain (arginine at position 5) and the sequence previously reported for the Balb/c strain (lysine). The promoter region immediately upstream of the dominant first exon is functional, transcriptionally responds to oxidative stress, and is highly homologous to the human region.

Synthesis and biological activity of enantiomers of antitumor irofulven.

Stereoselective synthesis of (-)-irofulven has been achieved by cycloaddition of (R)-5-chloro-5-methyl-2-cyclopentenone to the 1,3-dipolar intermediate from 1-acetyl-1-(diazoacetyl)cyclopropane. The enantiomer, (+)-irofulven, was prepared in a similar way starting with (S)-5-chloro-5-methyl-2-cyclopentenone. (+)-Irofulven was 5 to 6 times less toxic than (-)-irofulven to adenocarcinoma (MV 522) cells.

Structure-activity relationship studies of illudins: analogues possessing a spiro-cyclobutane ring.

Bicyclic and tricyclic analogues of anticancer sesquiterpene illudin S have been synthesized. These contain a spiro-cyclobutane instead of spiro-cyclopropane structure. The cytotoxicity of the former is less than that of the corresponding cyclopropane-containing compounds.

Basal expression of the human MAPEG members microsomal glutathione transferase 1 and prostaglandin E synthase genes is mediated by Sp1 and Sp3.

Microsomal glutathione transferase (MGST1) and prostaglandin E synthase (PGES) are both members of the MAPEG (Membrane Associated Proteins involved in Eicosanoid and Glutathione metabolism) superfamily. In humans, their organ distribution is quite distinct with the former being widely and constitutively expressed whereas PGES is largely inducible. In order to study the basal expression of these genes, we characterized the promoter regions and identified the elements and the transcription factors required using in vitro assays, including reporter analysis of deletion and mutant clones and EMSA.

Reaction of irofulven with zinc and acid.

Reaction of antitumor agent irofulven (1) with zinc and acetic acid yielded several new indene derivatives (6, 7, 8, 10) as well as the known indene (9). These all have greatly reduced toxicity to human leukemia (HL60) cells compared to irofulven.

Anti-tumour compounds illudin S and Irofulven induce DNA lesions ignored by global repair and exclusively processed by transcription- and replication-coupled repair pathways.

Illudin S is a natural sesquiterpene drug with strong anti-tumour activity. Inside cells, unstable active metabolites of illudin cause the formation of as yet poorly characterised DNA lesions. In order to identify factors involved in their repair, we have performed a detailed genetic survey of repair-defective mutants for responses to the drug.