Citations

ABSTRACT Mycobacterium peregrinum consists of two taxa: types I and II. We evaluated 43 clinical type II strains from throughout the United States. They were responsible for soft-tissue and bone infections, catheter-related infections, and possible pneumonitis. By carbohydrate utilization, they were indistinguishable from type I strains, being d -mannitol and trehalose positive. However, they had a distinct susceptibility pattern that included intermediate ciprofloxacin MICs but low clarithromycin and doxycycline MICs of ≤1 μg/ml. These features were also shared by reference isolates of Mycobacterium senegalense from African bovine cases of “farcy.” By 16S rRNA gene sequencing, the type II isolates shared 100% sequence identity with M. senegalense . Partial sequencing of the type II hsp65 gene (441 bp) revealed four sequevars showing ≥98.4% identity with each other and ≥98.6% identity with the sequence of five bovine strains of M. senegalense . There was ≤97.1% identity with M. peregrinum type I isolates and other Mycobacterium fortuitum group species. Sequencing of additional gene targets including the 16S-23S rDNA internal transcribed spacer region and the rpoB gene (partial sequence) revealed a similar phylogenetic grouping. DNA-DNA hybridization showed 76 to 99% relatedness between the bovine and human strains. These studies demonstrate that type II isolates are not isolates of M. peregrinum but represent human strains of M. senegalense . This study is the first to demonstrate this species as a human pathogen. Representative human M. senegalense strains include ATCC 35755 and newly submitted strains ATCC BAA-849, ATCC BAA-850, and ATCC BAA-851.

A transgenic mouse containing the complete human SLAM (hSLAM/CD150) gene, including its endogenous promoter for transcription, was generated by using human genomic DNA cloned into a bacterial artificial chromosome. hSLAM, the primary receptor for measles viruses (MV), was expressed on activated B, T, and dendritic cells with an expression profile equivalent to that of humans. We demonstrated that hSLAM + cells obtained from the transgenic mouse, including activated B, T, and dendritic cells, were susceptible to MV infection in a receptor-dependent manner. Evidence was provided for transient infection in the nasal lymph nodes of hSLAM + mice after intranasal inoculation. Virus was rapidly cleared without signs of secondary replication. To improve the efficiency of MV production, the hSLAM + mice were bred with mice having a Stat1 -deficient background. These mice were more susceptible to MV infection and produced more virus particles. After intranasal and intraperitoneal inoculation of these mice with MV, infections of the thymus, spleen, nasal, mesenteric, and leg lymph nodes were detected. Upon necropsy, enlarged lymph nodes and spleen were apparent. Flow cytometric analysis showed that abnormally large numbers of mature neutrophils and natural killer cells caused the splenomegaly. The hSLAM transgenic mouse constitutes an improved rodent model for studying the interaction of MV with immune cells that more accurately reflects the infection pattern found in humans.

Purpose A traditional end point for colon adjuvant clinical trials is overall survival (OS), with 5 years demonstrating adequate follow-up. A shorter-term end point providing convincing evidence to allow treatment comparisons could significantly speed the translation of advances into practice. Methods Individual patient data were pooled from 18 randomized phase III colon cancer adjuvant clinical trials. Trials included 43 arms, with a pooled sample size of 20,898 patients. The primary hypothesis was that disease-free survival (DFS), with 3 years of follow-up, is an appropriate primary end point to replace OS with 5 years of follow-up. Results The recurrence rates for years 1 through 5 were 12%, 14%, 8%, 5%, and 3%, respectively. Median time from recurrence to death was 12 months. Eighty percent of recurrences were in the first 3 years; 91% of patients with recurrence by 3 years died before 5 years. Correlation between 3-year DFS and 5-year OS was 0.89. Comparing control versus experimental arms within each trial, the correlation between hazard ratios for DFS and OS was 0.92. Within-trial log-rank testing using both DFS and OS provided the same conclusion in 23 (92%) of 25 cases. Formal measures of surrogacy were satisfied. Conclusion In patients treated on phase III adjuvant colon clinical trials, DFS and OS are highly correlated, both within patients and across trials. These results suggest that DFS after 3 years of median follow-up is an appropriate end point for adjuvant colon cancer clinical trials of fluorouracil-based regimens, although marginally significant DFS improvements may not translate into significant OS benefits.

Background— The goal of this study was to determine whether the expression of vascular endothelial growth factor (VEGF) is critical for coronary collateral growth. Previous studies have provided an association between coronary collateral growth and VEGF, but none have allowed determination of a causal role. Methods and Results— We measured coronary collateral growth in rats subjected to repetitive episodes of myocardial ischemia (RI; one 40-second occlusion every 20 minutes for 2 hours 40 minutes, followed by 5 hours 20 minutes of rest, with this 8-hour cycle repeated 3 times per day for 10 days). Collateral growth was measured from blood flow (radioactive microspheres), visualization of arterial-arterial anastomoses (x-ray micro-CT), and maintenance of function during complete coronary occlusion in 3 groups of animals: sham (received instrumentation but no RI), experimental (subjected to RI), and anti–vascular endothelial growth factor (RI+anti-VEGF 0.6 mg/100 g per day) to block the endogenous actions of VEGF. In the 3 groups, native collateral flow (measurement for RI or sham protocol) averaged 0.2 to 0.3 mL · min −1 · g −1 of tissue. In the sham group, collateral flow did not increase during the protocol. Collateral flow in the control RI group increased by ≈6-fold to 1.63 mL · min −1 · g −1 tissue, but in the anti-VEGF group, collateral flow did not increase after the RI protocol (0.22 mL · min −1 · g −1 ). In acute experiments, collateral flow was unchanged during vasodilation with dipyridamole, indicating the increases in collateral flow are due to collateral growth and not vasodilation. X-ray micro-CT analysis revealed a 3-fold increase (versus sham group) in the number of arterial-arterial anastomoses per heart after RI, which was prevented by treatment with anti-VEGF. The growth of the collateral circulation was functional in the RI group because complete coronary occlusion did not induce any untoward effects on hemodynamics or arrhythmias. In the sham or anti-VEGF groups, coronary occlusion at the end of the protocol induced many arrhythmias and deterioration of function. Conclusions— From these results, we conclude that the expression of VEGF is critical to the growth of coronary collaterals.

Purpose The objective of this study was to determine prognostic factors for overall survival in patients with post-transplantation lymphoproliferative disorders (PTLDs). Patients and Methods This study focused on the 107 adult solid organ transplantation patients who were diagnosed with PTLDs at Mayo Clinic (Rochester, MN) between December 1970 and May 2003. Results The median age at the time of diagnosis was 48 years (range, 15 to 75 years). Extranodal disease including grafted organ involvement was present in 85 patients (80%). The graft organ was involved in 30 patients (28%). At the time of these analyses, 62 patients (58%) had died. The median survival for the entire cohort was 31.5 months (95% CI, 10.7 to 72.5 months). The median follow-up of living patients was 51.8 months (range, 5.6 to 202.6 months). In univariate analyses for overall survival from the time of PTLD diagnosis, the following poor prognostic factors were identified: poor performance status with Eastern Cooperative Oncology Group levels 3 and 4 (P < .0001), grafted organ involvement (P = .0005), the presence of one or more extranodal sites (P = .005), both nodal and extranodal disease (P = .002), high International Prognostic Index (P = .006), advanced stage (P = .001), and elevated lactate dehydrogenase (P = .03). A final multivariable model for survival was constructed using three factors: poor performance status (3 to 4), monomorphic disease, and graft organ involvement. Conclusion A prognostic model has been developed for PTLD patients using one center's 30 years of experience. We propose additional confirmation and validation of these prognostic factors in larger prospective studies.