Citations

The mammalian dynamin-like protein DLP1/Drp1 has been shown to mediate both mitochondrial and peroxisomal fission. In this study, we have examined whether hFis1, a mammalian homologue of yeast Fis1, which has been shown to participate in mitochondrial fission by an interaction with DLP1/Drp1, is also involved in peroxisomal growth and division. We show that hFis1 localizes to peroxisomes in addition to mitochondria. Through differential tagging and deletion experiments, we demonstrate that the transmembrane domain and the short C-terminal tail of hFis1 is both necessary and sufficient for its targeting to peroxisomes and mitochondria, whereas the N-terminal region is required for organelle fission. hFis1 promotes peroxisome division upon ectopic expression, whereas silencing of Fis1 by small interfering RNA inhibited fission and caused tubulation of peroxisomes. These findings provide the first evidence for a role of Fis1 in peroxisomal fission and suggest that the fission machinery of mitochondria and peroxisomes shares common components.

Background— Most studies that are the basis of recommended volume thresholds for percutaneous coronary interventions (PCIs) predate the routine use of stent placement. Methods and Results— Data from New York’s Percutaneous Coronary Interventions Reporting System in 1998 to 2000 (n=107 713) were used to examine the impact of annual hospital volume and annual operator volume on in-hospital mortality, same-day coronary artery bypass graft (CABG) surgery, and same-stay CABG surgery after adjustment for differences in patients’ severity of illness. For a hospital-volume threshold of 400, the odds ratios for low-volume hospitals versus high-volume hospitals were 1.98 (95% CI, 1.17, 3.35) for in-hospital mortality, 2.07 (95% CI, 1.36, 3.15) for same-day CABG surgery, and 1.51 (95% CI, 1.03, 2.21) for same-stay CABG surgery. For an operator-volume threshold of 75, the odds ratios for low-volume versus high-volume operators were 1.65 (95% CI, 1.05, 2.60) for same-day CABG surgery and 1.55 (95% CI, 1.10, 2.18) for same-stay CABG surgery. Operator volume was not significantly associated with mortality. Also, for hospital volumes below 400 and operator volumes below 75, the respective odds of mortality, same-day CABG surgery, and same-stay CABG surgery were 5.92, 4.02, and 3.92 times the odds for hospital volumes of 400 or higher and operator volumes of 75 or higher. Conclusions— Higher-volume operators and hospitals continue to experience lower risk-adjusted PCI outcome rates.

AbstractThe latest World Health Organization International Classification defines papillary thyroid carcinoma by its “follicular cell differentiation. .. as well as characteristic nuclear changes”. However the oxyphilic (Hürthle cell) papillary carcinoma have nuclei which generally resemble the nuclei seen in oxyphilic follicular carcinomas, and such oxyphilic papillary tumors may behave more aggressively than typical papillary cancers. To further characterize these rare tumors, we identified during a 32‐year period 22 patients with oxyphilic papillary cancer and compared them with 1,084 patients with typical papillary cancers and 57 patients with oxyphilic follicular cancers treated by the Mayo surgical group during the same time period. Although typical papillary and oxyphilic papillary cancers were comparable with regards to patient age, tumor size and extent, TNM stage, and prognostic score (AGES), there were significant differences. Compared to typical papillary tumors, oxyphilic papillary cancers had fewer neck nodal metastases at primary diagnosis (5% vs 40%,p<0.0001), were more often DNA non‐diploid (71% vs 21%,p<0.001), and after 10 postoperative years had higher rates of both tumor recurrence (28% vs 11%,p<0.0001) and cause‐specific mortality (1.7% vs 4%,p<0.0005). In these four important respects the oxyphilic papillary cancers more resembled the oxyphilic follicular cancers. For oxyphilic follicular cancers, the frequency of initial neck nodal metastases was 7% (cf 5%); 83% of the oxyphilic follicular tumors were non‐diploid (cf 71%), and at 10 years postoperatively the tumor recurrence and cause‐specific mortality rates were 28% and 18%, insignificantly different from 28% and 17% seen with the oxyphilic papillary cancers. These results demonstrate that oxyphilic papillary tumors are more similar to oxyphilic follicular than typical papillary cancers, and suggest that in a differentiated follicular cell‐derived carcinoma a predominance of oxyphilic cells may be a prognostically more relevant feature than the individual tumor's predominant papillary or follicular morphologic pattern. Perhaps in future Histologic Classifications the World Health Organization should group the oxyphilic papillary cancers with the oxyphilic follicular rather than the typical papillary carcinomas.

AbstractWhereas excisional surgery and radiotherapy have resulted in a favorable outcome when non‐Hodgkin's lymphoma of the thyroid (NHLT) is confined to the thyroid gland, controversy persists over the potential advantage of aggressive debulking in favor of diagnostic biopsy alone when disease cannot be completely resected. Our aims in this study were to delineate the present role of surgery in NHLT in pre‐operative staging, the impact of the extent of resection on achieving complete remission and cause‐specific survival, and patterns of failure. All 62 patients who underwent primary surgery for NHLT at the Mayo Clinic between 1965 and 1989 were analyzed. By postoperative staging, 50 patients were stage IE or IIE. Overall survival was 53% and 46% at 5 and 10 years; 80% for stage IE confined to the thyroid, 58% for stage IE‐extrathyroid, 50% for stage IIE, and 36% for stages IIIE and IVE. Complete remission was achieved in 88% of patients who underwent diagnostic biopsy plus adjuvant therapy alone compared to 85% for patients in whom debulking plus adjuvant therapy was used. There was no difference in cause‐specific survival in these two groups or in cause‐specific survival in two subgroups who achieved complete remission. Relapse after complete remission occurred in 12 (26%) of 46 patients, only 2 of whom survived long‐term after salvage therapy. The role of surgery in NHLT is diminishing and advances that will increase complete remission and relapse‐free survival will not likely involve more aggressive surgical resections.

AbstractAmong 971 patients with chronic ulcerative colitis who underwent ilealpouch anal anastomosis during an 8‐year period from January, 1982 to December 1989, 30 patients were randomly selected from each year (total = 240 patients) for an assessment of their long‐term functional results and quality of life as of 1990. Patients undergoing cholecystectomy during each of the same years served as “controls” (20 patients/year, total = 160 patients). All 400 patients completed a written questionnaire that measured bowel habits, overall quality of life, general health, and performance in sports/recreation, travel, sex life, family relationship, occupational work, social activities, and household activities. Ileo‐anal patients had more frequent stools (median, 6 stools/day) and more fecal spotting (68% of patients had episodes) than cholecystectomy patients (median, 1 stool/day, 13% had episodes,p<0.05). In spite of the altered bowel habits, 90% of ileo‐anal patients had an excellent overall quality of life, 76% enjoyed good health, and 91% had good performance scores in the areas examined. In fact, quality of life and performance were similar among ileo‐anal patients and cholecystectomy patients. Moreover, quality of life and bowel habits remained steady in both groups of patients during the 8‐year follow‐up. In conclusion, functional results were satisfactory and quality of life was excellent after ileal pouch‐anal anastomosis; neither deteriorated as patients aged over an 8‐year period after operation.