2 CTC

2 CTC

5-Cyano-2,3-ditolyl tetrazolium chloride (CTC) reduction in a mesophilic anaerobic digester: measuring redox behavior, differentiating abiotic reduction, and comparing FISH response as an activity indicator.[Pubmed:12401227]

J Microbiol Methods. 2003 Jan;52(1):59-68.

The tetrazolium salt 5-cyano-2,3-ditolyl tetrazolium chloride (CTC) has been widely applied to assess microbiological activity in environmental samples. CTC reduction has previously been quantified in a variety of anaerobic systems (i.e., fermentative, nitrate reducing, sulfate reducing) using direct microscopy, solvent extraction, and flow cytometry. In this work, extracellular CTC reduction was observed and distinguished from its intercellular counterparts by the amorphous character and near uniform fluorescence of the resulting formazan precipitates (CTF). Fluorescence yielded by non-cellular-associated formazan precipitates bleached much more rapidly than CTF formed within cells under identical UV exposure (<2 min). Dehydrogenase activity assays and fluorescent in situ hybridization (FISH) were simultaneously carried out in microcosms containing active anaerobic digester biomass, propylene glycol, and settled sewage centrate for direct comparison. In substrate limited microcosms, quantitative FISH measurements remained well above their detection limit indicating sustained intercellular ribosomal RNA concentrations over a 5-day period, while dehydrogenase assays (CTC) decreased to background levels within 14 h of substrate limitation. Results from this work suggest that CTC reduction in cell-free samples may impede accurate enzyme activity measurements, particularly when quantification involves solvent extraction, flow cytometry, or software-aided counting. In addition, activity assessment in anaerobic digesters using FISH and CTC reduction assays may be comparable until substrate becomes limited.

New reduction pathways for ctc-[PtCl2(CH3CO2)2(NH3)(Am)] anticancer prodrugs.[Pubmed:20198227]

Chem Commun (Camb). 2010 Mar 21;46(11):1842-4.

Reduction of anticancer prodrugs such as ctc-[PtCl(2)(CH(3)CO(2))(2)(NH(3))(Am)] can yield three products in addition to the expected cis-[PtCl(2)(NH(3))(Am)]. A possible explanation is that reduction proceeds by several pathways where in addition to the loss of two axial ligands, one axial (acetato) and one equatorial (chlorido) ligand, or two equatorial ligands are eliminated.

Regimen-related toxicity following reduced-intensity stem-cell transplantation (RIST): comparison between Seattle criteria and National Cancer Center Common Toxicity Criteria (NCI-CTC) version 2.0.[Pubmed:15361909]

Bone Marrow Transplant. 2004 Nov;34(9):787-94.

Acute regimen-related toxicity (RRT) is minimal in reduced-intensity stem-cell transplantation (RIST). However, the Seattle RRT grading (Bearman et al), developed in the context of conventional-intensity transplantation, is frequently applied to RIST. We compared the National Cancer Institute Common Toxicity Criteria (NCI-CTC) version 2.0 with the Seattle criteria after RIST in 86 patients. RRT within 30 days of transplant graded by both sets of criteria were significantly associated with the outcome confirming the predictive value of both the systems. A total of 15 patients died of disease progression, and 12 of transplant-related mortality: RRT (n = 2), graft-versus-host disease (GVHD) (n = 7), infection (n = 1), and others (n = 2). GVHD-related deaths primarily resulted from infections after steroid treatment (n = 6) and bronchiolitis obliterans (n = 1). This study shows that NCI-CTC is appropriate in toxicity evaluation of RIST, and that its application to RIST enables a toxicity comparison between RIST and other types of cancer treatments. Since GVHD is a significant problem in RIST, modifications are required to evaluate immunological complications following RIST.