Survival after pelvic lymphadenectomy and radical cystectomy in patients with lymph-node metastatic transitional-cell carcinoma of the bladder

The objective of this study was to determine the clinical outcome of patients with invasive transitional cell carcinoma of the bladder and pelvic lymph node metastases treated by radical cystectomy and bilateral pelvic lymphadenectomy in a single institution. From January 1980 to December 1993, 116 patients with transitional cell carcinoma of the bladder underwent bilateral pelvic lymphadenectomy and radical cystectomy at the Montreal General Hospital. Of these patients, 25 (21.6%) were found to have nodal metastases and form the basis of this retrospective analysis. Extent of nodal disease was as follows: 7 (28%) with N1, 17 (68%) with N2, and 1 (4%) patient with N3 disease. Of the 25 patients, 9 (36%) were alive with no evidence of disease and 1 (4%) died at 42 months from cardiovascular disease without clinical evidence of cancer recurrence. The median follow-up interval for these 10 patients was 26.5 months (mean, 31.4 months; range, 7-104 months). Fourteen (56%) patients died of recurrent bladder cancer and one patient was alive with systemic disease at 14 months. The median survival was estimated at 27 months, with 73% alive at 1 year, 51% alive at 2 years, and 33% alive at 3 years. Our data suggests that long-term survival free of disease can be achieved by radical surgery in some patients with node-positive bladder cancer.

A reappraisal of the incremental packing technique for light cured composite resins

The cuspal flexure caused by a direct placement composite resin was measured using a technique that did not interfere with cuspal movement. Twenty upper premolar teeth with mesial-occlusal-distal (MOD) cavity preparations were restored using a posterior composite resin. Ten teeth were restored using a bulk packing technique and 10 were restored using three 'U' shaped bucco-lingual increments. Total cuspal movement was measured 1 h following the initiation of curing. Bulk placement of the composite resin produced slightly more cuspal movement (12.5 microm) compared with the incremental placement of composite (11.3 microm). This difference was not statistically significant. The technique of incremental packing to reduce cuspal flexure is therefore questioned.

Proteasomes modulate balance among proapoptotic and antiapoptotic Bcl-2 family members and compromise functioning of the electron transport chain in leukemic cells

The mechanism underlying apoptosis induced by proteasome inhibition in leukemic Jurkat and Namalwa cells was investigated in this study. The proteasome inhibitor lactacystin differentially regulated the protein levels of proapoptotic Bcl-2 family members and Bik was accumulated at the mitochondria. Bik overexpression sufficed to induce apoptosis in these cells. Detailed examination along the respiration chain showed that lactacystin compromised a step after complex III, and exogenous cytochrome c could overcome this compromise. Probably as a result, the succinate-stimulated generation of mitochondrial membrane potential was significantly diminished. Bcl-x(L) interacted with Bik in the cells, and Bcl-x(L) overexpression prevented cytochrome c leakage out of the mitochondria, corrected the mitochondrial membrane potential defect, and protected the cells from apoptosis. These results show that proteasomes can modulate apoptosis of lymphocytes by affecting the half-life of Bcl-2 family members, Bik being one of them.

Hydrolysed casein diet protects BB rats from developing diabetes by promoting islet neogenesis

Feeding diabetes-prone BioBreeding (BBdp) rats a hydrolysed-casein (HC)-based semi-purified diet results in two-to-three-fold fewer diabetes cases compared with feeding cereal-based diets such as NIH-07 (NIH). We showed previously that young NIH-fed BBdp rats had decreased islet area at a time when classic insulitis was minimal. Rats fed an HC diet maintained near normal islet area followed 3-4 weeks later by a deviation of the pancreas cytokine pattern from Th1 to Th2/Th3. This finding raised the possibility that BBdp rats were more susceptible to diet-induced changes in islet homeostasis. To investigate this possibility further, BBdp rats were fed an NIH or HC diet from days 23 to 45. Bouin's fixed sections of pancreas were stained with H & E or antibodies for insulin and glucagon. Cell proliferation nuclear antigen (PCNA) was used as a marker of cell proliferation and cells were stained for putative markers of islet neogenesis, cytokeratin 20 (CK20) and Bcl-2. Apoptotic bodies were recognized by morphological features and by TUNEL-positive staining. BBdp rats fed an HC diet had a significantly higher beta-cell fraction than rats fed NIH, whereas alpha-cell fraction and beta-cell size were not affected by diet or rat type. Apoptotic bodies of beta-cells were rare and unaffected by diet. The number of PCNA(+)beta-cells was not affected by diet. CK20 expression was localized in the ductular system and at the periphery of islets in rats aged 7 and 45 days. There were more CK20(+)islets in BBdp rats fed NIH than in those fed HC but the CK20 area fraction was unaffected by diet. Bcl-2 expression was scattered among ducts and central acinar cells. The number of extra-islet insulin(+)and glucagon(+)clusters (<four cells) was significantly higher in animals fed the HC diet compared with those fed NIH. Most of the insulin(+)clusters were also homeodomain-containing transcription factor pancreas duodenum homeobox gene-1 (PDX-1) positive. Glucagon(+)/PDX-1(+)clusters were rarely found. These data are consistent with a shift in pancreas homeostasis that maintains islet cell mass by increased islet neogenesis, a process that was enhanced in animals fed a diabetes-retardant diet.

Role of proteasomes in T cell activation and proliferation

The role of proteasomes in T cell activation, proliferation, and apoptosis was investigated using a proteasome-specific inhibitor lactacystin (LAC). Inhibition of the proteasome activity by LAC repressed the mitogen-induced T cell proliferation. The proteasome activity was definitively required for the T cells to progress from the G0 to S phase. It was necessary to optimize the progress from the G1/S boundary to the G2/M phase, but not for the progress from the G2/M phase to the next G1 phase. Probably as a result of a blockage of cell cycle progress, the cycling, but not the resting, T cells underwent apoptosis when treated with LAC. Mechanistically, we have found that cyclin-dependent kinase-2 (CDK2) and the cyclin E-associated kinase (largely CDK2), but not CDK4, in the G1 phase were strongly inhibited by LAC. This could be an important mechanism for the proteasome to regulate the cell cycle. The degradation of cyclin E in the late G1 and early S phases was dependent on the proteasome, although it was unlikely that this accounted for the observed inhibition of T cell proliferation. There was a reduced decay of p27Kip1 in the late G1 phase when the proteasome activity was suppressed, and this might be a contributing mechanism for the observed inhibition of CDK2 activity. Interestingly, p21Cip1 was up-regulated during the G1 phase, and the up-regulation was inhibited by LAC. Our study shows that the proteasome plays pivotal roles in regulating T cell activation and proliferation, and its effect is probably exerted through multiple mechanisms.

The effect of rapamycin on T cell development in mice

Rapamycin (RAPA) is a strong immunosuppressant with a chemical structure similar to that of FK506, although it acts by a mechanism different from both FK506 and cyclosporin A. The effect of RAPA on T cell development in mice was investigated in this study. RAPA caused significant thymic atrophy. The major histological change in the RAPA-treated thymus was thinning of the cortex. No other apparent damage in the cortex or medulla was observed. Consistent with these histological findings, in vivo thymocyte cycling was blocked by RAPA before the S phase, and the ex vivo and in vitro proliferation of the thymocytes was also strongly repressed by the drug. According to electron microscopy and DNA fragmentation assays, RAPA did not induce apoptosis. These results indicate that the repressed thymocyte proliferation is a major mechanism causing RAPA-induced thymic atrophy. Further, RAPA had no effect on thymocyte apoptosis induced by anti-CD3 or ionomycin, and the drug did not interfere with deletion of CD4+8+ thymocytes or peripheral V beta 6+ T cells induced by anti-CD3 or Mls-1a, respectively. These data suggest that RAPA does not hamper the negative selection. There was a relative increase in the CD3- fraction of the de novo developing CD4 and CD8 double-positive (DP) thymocytes in the RAPA-treated mice. Moreover, there were relative increases of the CD3-fractions of the CD4 or CD8 single-positive (SP) cells in both the thymi and periphery. The generation of the CD3-SP under the influence of RAPA could be used as a useful model for further study of the function and signal transduction of these CD3-defective SP cells.

Fungal infections in cancer patients: an international autopsy survey

In an attempt to estimate the frequency of fungal infections among cancer patients, a survey of autopsy examinations was conducted in multiple institutions in Europe, Japan and Canada. Fungal infections were identified most often in leukemic patients and transplant recipients (25% each). Fifty-eight percent of fungal infections were caused by Candida spp. and 30% by Aspergillus spp. There was considerable variability in the frequency of fungal infections in different countries. Nevertheless, this study clearly demonstrates that fungal infections represent a common complication in cancer patients, especially in patients with leukemia.