Hypersensitivity reactions associated with fidaxomicin use.

We report hypersensitivity reactions associated with fidaxomicin, an antibacterial drug approved for the treatment of Clostridium difficile-associated diarrhea. These reactions are viewed as significant because of severity and unexpected because fidaxomicin is minimally absorbed. The fidaxomicin labeling was revised to include information about the possibility of hypersensitivity reactions.

Low prevalence of primary HIV resistance in western Massachusetts.

Most studies of primary antiretroviral (ARV) resistance have been conducted in large metropolitan areas with reported rates of 8% to 25%. We collected data on 99 HIV-1-infected antiretroviral-naive patients from several sites in Springfield, MA, who underwent genotypic resistance assay between 2004 and 2008. Only major resistance mutations per International AIDS Society-USA (IAS-USA) drug resistance mutations list were considered. The prevalence of resistance was 5% (5 of 99). Three patients had one nonnucleoside reverse transcriptase inhibitor (NNRTI) mutation: 103N, 103N, and 190A, 1 patient had a protease inhibitor (PI) mutation: 90M; and 1 patient had 3-class resistance with NNRTI: 181C, 190A, PI: 90M, and nucleoside analogue reverse transcriptase inhibitor (NRTI): 41L, 210W. Mean time from HIV diagnosis to resistance testing was shorter in patients with resistance versus those without: 9 (range 0.3-42 months) versus 27 (range 0.1-418 months), P = .11. There was a trend to lower mean CD4 count in those with resistance, 170 versus 318 cells/mm(3), P = .06. No differences were noted in gender, age, HIV risk category, or HIV RNA level. The low prevalence of primary resistance may be explained by differences in demographic and risk factors or may reflect the time from infection to resistance testing. Our findings emphasize the importance of continued resistance surveillance.

Delayed transplantation with exogenous neurotrophin administration enhances plasticity of corticofugal projections after spinal cord injury.

Functional deficits following spinal cord injury (SCI) result from a disruption of corticofugal projections at the lesion site. Not only direct regeneration of the severed axons but also anatomical re-organization of spared corticofugal pathways can reestablish connections between the supraspinal and spinal motor centers. We have previously shown that delayed transplantation of fetal spinal cord tissue and neurotrophin administration by two weeks after SCI supported recovery of forelimb function in adult rats. The current study determined whether the same intervention enhances plasticity of corticofugal fibers at the midbrain and spinal cord level. Anterograde tracing of the left corticorubral fibers revealed that the animals with transplants and neurotrophins (BDNF or NT-3) increased the extent of the traced fibers crossing to the right red nucleus (RN), of which the axons are spared by a right cervical overhemisection lesion. More neurons in the left motor cortex were recruited by the treatment to establish connections with the right RN. The right corticorubral projections also increased the density of midline crossing fibers to the axotomized left RN in response to transplants and neurotrophins. Transplants plus NT-3, but not BDNF, significantly increased the amount of spared corticospinal fibers in the left dorsolateral funiculus at the spinal level both rostral and caudal to the lesion. These results suggest that corticofugal projections retain the capacity until at least two weeks after injury to undergo extensive reorganization along the entire neuraxis in response to transplants and neurotrophins. Targeting anatomical plasticity of corticofugal projections may be a promising strategy to enhance functional recovery following incomplete SCI.

Use of HIV resistance testing after prolonged treatment interruption.

BACKGROUND: HIV-1 genotypic resistance testing is not routinely recommended for patients who have been off antiretroviral therapy (ART) for longer than 4 weeks. We assessed the results and use of resistance testing in patients off ART. METHODS: All HIV resistance genotypes from November 2003 through April 2008 were reviewed from one large teaching hospital and two private HIV practices. Inclusion criterion was having a genotypic resistance test after an ART interruption of at least 2 months. Medical records were reviewed using a standardized data collection sheet. RESULTS: Sixty-two of 304 treatment-experienced patients with HIV genotypes met the inclusion criteria. Prior cumulative ART class exposure included nucleoside reverse transcriptase inhibitors in 54 patients, nonnucleoside reverse transcriptase inhibitors in 32 patients, and protease inhibitors in 30 patients. Resistance testing was performed at a mean of 12 months (range, 2.5-48 months) after ART interruption. The mean time between ART interruption and resistance testing did not differ for patients with mutations and those without mutations detected. Seventeen of 62 (27.4%) patients were found to have resistance mutations. Eleven patients were found to have mutations to nonnucleoside reverse transcriptase inhibitors, four patients had mutations to nucleoside reverse transcriptase inhibitors, and two patients had protease inhibitor-associated mutations. No patient had multiclass resistance. Among the 17 patients with mutations after treatment interruption, 15 had mutations that were either not present on a prior genotype (n = 2) or did not have a prior genotype (n = 13). CONCLUSIONS: HIV genotypic resistance assays may identify mutations even when performed after a prolonged treatment interruption and may offer clinically significant information. Current guidelines that discourage resistance testing after treatment interruptions of longer than 4 weeks should be re-evaluated.