Citations

ABSTRACT Recent molecular studies have shown Mycobacterium porcinum , recovered from cases of lymphadenitis in swine, to have complete 16S rDNA sequence identity and >70% DNA-DNA homology with human isolates within the M. fortuitum third biovariant complex. We identified 67 clinical and two environmental isolates of the M. fortuitum third biovariant sorbitol-negative group, of which 48 (70%) had the same PCR restriction enzyme analysis (PRA) profile as the hsp65 gene of M. porcinum (ATCC 33776 T ) and were studied in more detail. Most U.S. patient isolates were from Texas (44%), Florida (19%), or other southern coastal states (15%). Clinical infections included wound infections (62%), central catheter infections and/or bacteremia (16%), and possible pneumonitis (18%). Sequencing of the 16S rRNA gene (1,463 bp) showed 100% identity with M. porcinum ATCC 33776 T . Sequencing of 441 bp of the hsp65 gene showed four sequevars that differed by 2 to 3 bp from the porcine strains. Clinical isolates were positive for arylsulfatase activity at 3 days, nitrate, iron uptake, d -mannitol, i- myo -inositol, and catalase at 68°C. They were negative for l -rhamnose and d -glucitol (sorbitol). Clinical isolates were susceptible to ciprofloxacin, sulfamethoxazole, and linezolid and susceptible or intermediate to cefoxitin, clarithromycin, imipenem, and amikacin. M. porcinum ATCC 33776 T gave similar results except for being nitrate negative. These studies showed almost complete phenotypic and molecular identity between clinical isolates of the M. fortuitum third biovariant d -sorbitol-negative group and porcine strains of M. porcinum and confirmed that they belong to the same species. Identification of M. porcinum presently requires hsp65 gene PRA or 16S rRNA or hsp65 gene sequencing.

While the subcellular organisation of mitochondria is likely to influence many aspects of cell physiology, its molecular control is poorly understood. Here, we have investigated the role of the retrograde motor protein complex, dynein-dynactin, in mitochondrial localisation and morphology. Disruption of dynein function, achieved in HeLa cells either by over-expressing the dynactin subunit, dynamitin (p50), or by microinjection of an anti-dynein intermediate chain antibody, resulted in (a) the redistribution of mitochondria to the nuclear periphery, and (b) the formation of long and highly branched mitochondrial structures. Suggesting that an alteration in the balance between mitochondrial fission and fusion may be involved in both of these changes, overexpression of p50 induced the translocation of the fission factor dynamin-related protein (Drp1) from mitochondrial membranes to the cytosol and microsomes. Moreover, a dominant-negative-acting form of Drp1 mimicked the effects of p50 on mitochondrial morphology, while wild-type Drp1 almost completely restored normal mitochondrial distribution in p50 over-expressing cells. Thus, the dynein/dynactin complex plays an unexpected role in the regulation of mitochondrial morphology in living cells, by controlling the recruitment of Drp1 to these organelles.

AbstractWe compared the angiogenic potential of bone marrow plasma and the expression of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), and their receptors on plasma cells from patients with monoclonal gammopathy of undetermined significance (MGUS), smoldering multiple myeloma (SMM), and newly diagnosed multiple myeloma (NMM). Cytokine and cytokine-receptor expression was studied by bone marrow immunohistochemistry, quantitative reverse transcription-polymerase chain reaction (RT-PCR) on sorted plasma cells, and quantitative Western blot analysis. Bone marrow angiogenic potential was studied using a human in vitro angiogenesis assay. The expression levels of VEGF, bFGF, and their receptors were similar among MGUS, SMM, and NMM. Sixty-one percent of NMM samples stimulated angiogenesis in the in vitro angiogenesis assay compared with SMM (0%) and MGUS (7%) (P < .001). Importantly, 63% of MGUS samples inhibited angiogenesis compared with SMM (43%) and NMM (4%) (P < .001). The inhibitory activity was heat stable, not overcome by the addition of VEGF, and corresponded to a molecular weight below 10 kd by size-exclusion chromatography. Our results suggest that increasing angiogenesis from MGUS to NMM is, at least in part, explained by increasing tumor burden rather than increased expression of VEGF/bFGF by individual plasma cells. The active inhibition of angiogenesis in MGUS is lost with progression, and the angiogenic switch from MGUS to NMM may involve a loss of inhibitory activity. (Blood. 2004; 104:1159-1165)

Purpose Molecular studies of colon cancer have provided insights into pathogenesis, yet it is unclear how important these markers are in predicting prognosis. This study investigated the prognostic significance of TUNEL, bcl-2, p53, proliferation marker Ki-67 and DNA mismatch repair (MMR) status in patients with Dukes' stage B2 and C colorectal adenocarcinomas. Patients and Methods Tumor tissue from 366 patients (75% Dukes' C, 25% Dukes' B2) from four randomized North Central Cancer Treatment Group phase III surgical adjuvant trials were used. Eighty-one percent of patients received adjuvant treatment, which was primarily fluorouracil (FU) based (90%). Tumor location was predominantly (87%) the colon. Terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL), Ki-67, p53, bcl-2, and MMR were assayed using immunohistochemistry. Stage, grade, MMR, Ki-67, and previously determined flow cytometry markers (ploidy and S phase) were explored for associations with each other and with overall survival (OS) and disease-free survival (DFS). Results Univariately, stage B2, low grade, diploid, Ki-67 more than 27%, normal p53, and FU-based adjuvant treatment were significantly associated with improved OS and DFS (P < .05). After adjusting for stage, grade, and ploidy in multivariate analysis, Ki-67 remained significantly related to both OS and DFS (P < .01). Active FU-based adjuvant treatment was significant only for OS in this multivariate model. Neither bcl-2 nor TUNEL were significant. Conclusion This retrospective study indicates that Ki-67 and ploidy may have stronger prognostic impact on OS and DFS than other parameters investigated after adjusting for stage and tumor grade. Prospective studies to elucidate the mechanism and prognostic significance of these findings are necessary.

Purpose To determine survival and relapse rates by T and N stage and treatment method in five randomized phase III North American rectal adjuvant studies. Patients and Methods Data were pooled from 3,791 eligible patients enrolled onto North Central Cancer Treatment Group (NCCTG) 79-47-51, NCCTG 86-47-51, US Gastrointestinal Intergroup 0114, National Surgical Adjuvant Breast and Bowel Project (NSABP) R01, and NSABP R02. Surgery alone (S) was the treatment arm in 179 patients. The remaining patients received adjuvant treatment as follows: irradiation (RT) alone (n = 281), RT + fluorouracil (FU) ± semustine bolus chemotherapy (CT; n = 779), RT + protracted venous infusion CT (n = 325), RT + FU ± leucovorin or levamisole bolus CT (n = 1,695), or CT alone (n = 532). Five-year follow-up was available in 94% of surviving patients, and 8-year follow-up, in 62%. Results Overall (OS) and disease-free survival were dependent on TN stage, NT stage, and treatment method. Even among N2 patients, T substage influenced 5-year OS (T1-2, 67%; T3, 44%; T4, 37%; P < .001). Three risk groups of patients were defined: (1) intermediate (T1-2/N1, T3/N0), (2) moderately high (T1-2/N2, T3/N1, T4/N0), and (3) high (T3/N2, T4/N1, T4/N2). For intermediate-risk patients, those receiving S plus CT had 5-year OS rates of 85% (T1-2/N1) and 84% (T3/N0), which was similar to results with S plus RT plus CT (T1-2/N1, 78% to 83%; T3/N0, 74% to 80%). For moderately high-risk lesions, 5-year OS ranged from 43% to 70% with S plus CT, and 44% to 80% with S plus RT plus CT. For high-risk lesions, 5-year OS ranged from 25% to 45% with S plus CT, and 29% to 57% with S plus RT plus CT. Conclusion Different treatment strategies may be indicated for intermediate-risk versus moderately high- or high-risk patients based on differential survival rates and rates of relapse. Use of trimodality treatment for all patients with intermediate-risk lesions may be excessive, since S plus CT resulted in 5-year OS of approximately 85%; however, 5-year disease-free survival rates with S plus CT were 78% (T1-2/N1) and 69%(T3/N0), indicating room for improvement.

AbstractPrimary systemic amyloidosis (AL) is a fatal plasma cell disorder. Pilot data suggest survival is better in patients undergoing peripheral blood stem cell transplantation (PBSCT), but the selection process makes the apparent benefit suspect. We have reported that circulating cardiac biomarkers are the best predictors of survival outside of the transplantation setting. We now test whether cardiac troponins (cTnT and cTnI) and N-terminal pro-brain natriuretic peptide (NT-proBNP) are prognostic in transplant recipients. In 98 patients with AL undergoing PBSCT, serum cardiac biomarkers were measured (cTnT, 98 patients; cTnI, 65 patients; and NT-proBNP, 63 patients). Elevated levels of cTnT, cTnI, and NT-proBNP were present in 14%, 43%, and 48% of patients, respectively. At 20 months median follow-up, median survival has not been reached for patients with values below the thresholds; in patients with values above the thresholds, median survival is 26.1 months, 66.1 months, and 66.1 months, respectively. Our previously reported risk systems incorporating these markers were also prognostic, notably the cTnT/NT-proBNP staging. Using this system, 49%, 38%, and 13% of patients were in stage I, stage II, and stage III, respectively. Determining levels of circulating biomarkers may be the most powerful tool for staging patients with AL undergoing PBSCT.

Background and Purpose— Incomplete platelet inhibition by aspirin (aspirin resistance) may be a reason for stroke recurrence in some patients. 11-Dehydrothromboxane B2 (11-DTB2) is a stable thromboxane A2 metabolite that reflects in vivo platelet activation. This pilot study was intended to evaluate the reproducibility of urinary 11-DTB2 over time and to look for evidence of aspirin resistance. Methods— All subjects were screened for the African American Antiplatelet Stroke Prevention Study (AAASPS) 7 to 90 days after noncardioembolic cerebral infarction. Of 83 subjects with at least 1 urine sample, 52 were enrolled in AAASPS (randomized to blinded treatment with aspirin 650 mg/d or ticlopidine 500 mg/d), and 31 were enrolled in an open-label antiplatelet therapy cohort. Subjects were followed up for 2 years, with 11-DTB2 measurements scheduled at baseline and 6, 12, and 24 months. Vascular events were cerebral infarction, myocardial infarction, or vascular death. Results— Despite considerable individual up or down fluctuations, the median 11-DTB2 change did not significantly differ from zero in any of the subgroups. However, in 6 subjects with a 4-fold decrease in aspirin dose from 1300 to 325 or 81 mg/d, the 11-DTB2 level increased from 611 to 1881 pg/mg creatinine ( P =0.06). Vascular events occurred in 7 of 61 aspirin-treated subjects, and 11-DTB2 levels did not correlate with the events. Conclusions— Fluctuations in urinary 11-DTB2 after cerebral infarction in blacks do not correlate with changes in aspirin doses, except perhaps when the dose changes by a factor of 4 or more. A larger study is needed to look further for aspirin resistance.