[en] The authors have been studying the interaction between incidence of apoptosis and expression of selected oncogenes and cytokines in an in vivo rat model of ischaemia-reperfusion injury. The ischaemia itself, and the reperfusion, induce oxidative damage to the tissues, including damage from oxygen-derived free radicals. The scenario is therefore similar to radiation-induced injury. The proximal nephron segments, especially the pars recta, are usually acutely sensitive to ischaemia-reperfusion injury, undergoing necrosis in preference to apoptosis. A hypothesis was formed that Bcl-2 protection of the distal nephron, a segment of the nephron known as a reservoir for many growth factors or cytokines, allows increased production of growth factors during oxidative stress, which then act in a paracrine manner to protect the nearby proximal tubule. To test this hypothesis, an in vitro model of oxidative stress was used on either distal (Madin Derby Canine Kidney, MDCK) or proximal (human kidney-2, HK-2) established renal cell lines. We grow the cells as 'coverslip cultures' in 12-well plates in Dulbecco's Modified Eagle's Medium or serum free medium. The treatments used are either hydrogen peroxide (a gradation of concentrations from 1mM to 50 mM), tumour necrosis factor-alpha (TNF-alpha) or hypoxia, as inducers of oxidative stress. The parameters analysed in the present study were (i) cell death (apoptosis or necrosis, using histology, in situ end labelling, and electron microscopy) (ii) cell proliferation and (iii) Bcl-2 expression (immunohistochemistry). It was found that all treatments increase levels of apoptosis in both cell lines, and TNF-alpha also causes increased cell proliferation. At the higher concentrations of hydrogen peroxide however, the HK-2 (proximal) cells have more of a tendency to undergo necrosis than do the MDCK (distal) cells, mimicking the in vivo situation. Bcl-2 expression is low in both cell lines, and does not appear to be affected by the treatments in this model, and this is a divergence from the in vivo results

[en] The difference in incidence of radiation-induced apoptosis between two neonatal urogenital tissues, kidney and testis, was analysed over a 24h period. Concurrent administration of cycloheximide (10mg/kg body weight), a protein synthesis inhibitor, with radiation treatment was used to determine whether new protein synthesis had a role in induction of apoptosis in this in vivo model. Many chemotherapeutic drugs act via protein synthesis inhibition, and we believe that the results of this latter analysis may provide information for the planning of concurrent radio and chemotherapy. Apoptosis was quantified using morphological parameters, and verified by DNA gel electrophoresis for the typical banding pattern, and by electron microscopy. The proliferative index in tissues was studied, using [6-³H]-thymidine uptake ( 1h prior to euthanasia and collection of tissues) and autoradiography as indicators of cell proliferation (S-phase). Tissue was collected 2, 4, 6, 8, and 24h after radiation treatment. Expression of one of the apoptosis-associated genes, Bcl-2 (an apoptosis inhibitor/cell survival gene), was studied using immunohistochemistry. Apoptosis peaked at 4h in the testis and 6h in the kidney, emphasising the necessity of knowing tissue differences in radiation response if comparing changes at a particular time. A higher proportion (almost five fold) of the apoptotic cells died in S-phase in the kidney than the testis, over the 24h. Protein synthesis inhibition completely negated induction of apoptosis in both tissues. Necrosis was not identified at any time. Cycloheximide treatment greatly diminished Bcl-2 expression. The differences in response of the two tissues to irradiation relates to their innate cell (genetic) controls, which may be determined by their state of differentiation at time of treatment, or the tissue type. This in vivo study also suggests the model may be useful for analysis of other cancer therapies for example polychemotherapies or chemo-and radiotherapy

[en] Acute obstructions of the gastric outlet, the duodenum, or the large bowel require rapid treatment to relieve symptoms of retention or ileus. Large-caliber stents of 16 to 22 mm offer a new non-surgical alternative for treating these patients with minimal risks and high success rates. For gastroduodenal outlet obstructions palliated by self-expanded metal stents, clinical success rates are in the range of 80-100 %. Preoperative treatment of colorectal obstructions successfully relieves acute symptoms of ileus in 87-100 % allowing primary anastomosis and thereby reducing the costs caused by multiple operations and the need of intensive care by approximately 25 %. It is the purpose of this review to familiarize the reader with the indications, possibilities, and limits of intestinal stenting. (orig.)