Reasons for voriconazole prophylaxis discontinuation in allogeneic hematopoietic cell transplant recipients: A real-life paradigm.

We sought to describe the clinical experience of voriconazole as primary antifungal prophylaxis (AFP) in allogeneic hematopoietic cell transplant recipients (allo-HCTr). This was a single-center retrospective study of adult allo-HCTr (1 January 2014 to 31 December 2016) who received ≥two doses of voriconazole-AFP. Voriconazole-AFP was started on day +7 post-HCT and continued at least through day +60 post-HCT, or longer as clinically indicated. We reviewed the rate, reasons, and risk factors of voriconazole-AFP discontinuation until day-100 post-HCT. A total of 327 patients were included. Voriconazole-AFP was continued for a median of 69 days (mean: 57.9; range 1, 100): for a median of 90 days (mean :84; range 2, 100) in 180/327 (55%) in the standard-of-care (SOC) group and 20 days (mean :25.6 ; range 1, 89; P-value < .001) in 147/327 (45%) patients in the early-discontinuation-group. Early-voriconazole-AFP discontinuation was due to adverse events, drug interactions, insurance coverage, and other reasons in 101/147 (68.7%), 27 (18.4%), 13 (8.8%), and 6 (4.1%) patients, respectively. Early-voriconazole-AFP discontinuation occurred in 73/327 (22.3%) patients due to hepatotoxicity. Important predictors for early-voriconazole-AFP discontinuation included: graft-versus-host disease grade ≥2 (odds ratio [OR]: 1.9, P-value: .02), alanine-aminotransferase ≥75 IU/ml on voriconazole-administration day-14 (OR: 5.6, P-value: .02) and total bilirubin ≥1.3 mg/dl on voriconazole-administration day-7 (OR: 3.0, P-value: .03). There were 13 proven/probable invasive fungal infections by day-180 post-HCT (8/147, 5.4%, and 5/180, 2.8% in the early-discontinuation and SOC-groups, respectively; log-rank:0.13). By day-180 post HCT, 23/147 (15.6%) and 14/180 (7.8%) patients in the early-discontinuation and SOC-groups had died, respectively (log-rank:0.03). Voriconazole-AFP was discontinued in up to 45% of allo-HCTr. Hepatotoxicity during the first 2 weeks post-HCT is a significant predictor of early-voriconazole-AFP discontinuation.

C9orf72 expansion within astrocytes reduces metabolic flexibility in amyotrophic lateral sclerosis.

It is important to understand how the disease process affects the metabolic pathways in amyotrophic lateral sclerosis and whether these pathways can be manipulated to ameliorate disease progression. To analyse the basis of the metabolic defect in amyotrophic lateral sclerosis we used a phenotypic metabolic profiling approach. Using fibroblasts and reprogrammed induced astrocytes from C9orf72 and sporadic amyotrophic lateral sclerosis cases we measured the production rate of reduced nicotinamide adenine dinucleotides (NADH) from 91 potential energy substrates simultaneously. Our screening approach identified that C9orf72 and sporadic amyotrophic lateral sclerosis induced astrocytes have distinct metabolic profiles compared to controls and displayed a loss of metabolic flexibility that was not observed in fibroblast models. This loss of metabolic flexibility, involving defects in adenosine, fructose and glycogen metabolism, as well as disruptions in the membrane transport of mitochondrial specific energy substrates, contributed to increased starvation induced toxicity in C9orf72 induced astrocytes. A reduction in glycogen metabolism was attributed to loss of glycogen phosphorylase and phosphoglucomutase at the protein level in both C9orf72 induced astrocytes and induced neurons. In addition, we found alterations in the levels of fructose metabolism enzymes and a reduction in the methylglyoxal removal enzyme GLO1 in both C9orf72 and sporadic models of disease. Our data show that metabolic flexibility is important in the CNS in times of bioenergetic stress.

Computational analysis of stimulated dopaminergic synapses suggests release largely occurs from a single pool of vesicles.

Results from several experiments monitoring extracellular dopamine (DA) after stimulating axons at high frequencies have been interpreted as evidence for release from two populations of vesicles in dopaminergic varicosities. In addition, these experiments have suggested that cocaine and other dopamine transporter (DAT) inhibitors promote transfer of vesicles or dopamine itself from a reserve pool to a readily available pool. We developed a computer model simulation of these experiments with the goal of determining a set of mathematical formulas that describe dopamine movement between multiple storage compartments. However, the simulations show that data can be accurately simulated with release largely from a homogeneous population of vesicles, and that effects of dopamine transporter inhibitors can be explained without requiring that these drugs promote movement of dopamine from a reserve to an available pool. The data also suggest that dopamine recycling is highly efficient, even under high-frequency signaling conditions, and that the "kiss and run" mechanism of dopamine release probably predominates under conditions of very rapid neuron firing.