DNA repair mechanisms involved in the removal of DBPDE-induced lesions leading to chromosomal alterations in CHO cells.

Polycyclic aromatic hydrocarbons (PAH) such as dibenzo[a,l]pyrene (DBP) are wide-spread environmental pollutants most probably mutagenic and carcinogenic to humans. Detailed data on the cytogenetic effects of anti-11,12-dihydroxy-13,14-epoxy-11,12,13,14-tetrahydrodibenzo[a,l]pyrene (DBPDE) in mammalian cells are not available in the literature. The aim of this study is to elucidate the mechanisms involved in the induction of chromosomal aberrations and sister chromatid exchanges (SCEs) by DBPDE in mammalian cells. In order to achieve this a parental (AA8) and different DNA repair-deficient Chinese hamster ovary cell lines such as UV4, UV5, UV61 (nucleotide excision repair, NER), EM9 (base excision repair, BER), irs1SF (homologous recombination repair, HRR) and V3-3 (non-homologous end joining, NHEJ) were used. The most sensitive cell lines for DBPDE-induced chromosome aberrations were EM9 and irs1SF, while EM9 and V3-3 cell lines were the most sensitive in terms of SCEs induction. It can be suggested that the BER pathway plays an important role in the repair of lesions induced by DBPDE, affecting both chromosomal aberrations and SCEs induction. Moreover, the HRR pathway seems to play a role in cellular resistance to DBPDE mainly in terms of chromosomal aberration induction while the NHEJ pathway takes part affecting only the induction of SCEs.

Epidural anaesthesia for endovascular stent graft repair of a ruptured thoracic aneurysm.

We present a case report of the anaesthetic management of a 77-year-old man requiring endovascular thoracic stent graft repair. The patient had a history of poorly controlled type II diabetes mellitus and chronic renal failure. Chest X-ray and CT scan showed a right pleural effusion, generalized emphysema and an enlarged thyroid extending into the upper mediastinum, compromising the tracheal lumen. Endovascular stent graft repair was successfully performed under epidural anaesthesia and intravenous sedation.

Etiopatogenia de la úlcera aguda por estres: rol de los oxidantes derivados del oxígeno / Pathogenesis of gastric stress ulcer: role of oxygen free radicals

We evaluated the role of oxygen free radicals in the induction of acute stress gastric ulcer in rats. After 12 hr of inmobility, ulcers of up to 4 mm were observed in the gastric mucosa. Pretreatment with allopurinol, a xantine oxydase inhibitor, produced a significant reduction in the number and size of lesions (p < 0.0001). No protection was afforded by aluminum hydroxyde or ranitidine alone, but enhanced protection was observed when given in association to allopurinol. A secondary role for H ions is suggested by these findings. Our results support the hypothesis of a role of a oxygen free radicals in the pathogenesis of stress gastric ulcers. Allopurinol might be used in conditions prodisposing to stress in patients