Melatonin precursor; L-tryptophan protects the pancreas from development of acute pancreatitis through the central site of action.

Melatonin, produced from L-tryptophan, protects the pancreas against acute damage by improving the antioxidative status of tissue. Melatonin receptors have been detected in the brain, but the contribution of these receptors to the pancreatic protection is unknown. The aim of our study was to compare the effects of melatonin precursor; L-tryptophan given intracerebroventricularly (i.c.v.) or intraperitoneally (i.p.) on the course of acute pancreatitis. Acute pancreatitis was induced by subcutaneous infusion of caerulein (5 microg/kg-h x 5 h). L-tryptophan was given i.p. (2.5, 25 or 250 mg/kg) or administered into right cerebral ventricle (0.02, 0.2 or 2.0 mg/rat) 30 min prior to the start of caerulein infusion. Plasma amylase, lipase and TNF alpha activities were measured to determine the severity of caerulein-induced pancreatitis (CIP). The lipid peroxidation products: malonylodialdehyde and 4-hydroksynonenal (MDA + 4-HNE) and activity of superoxide dismutase (SOD) were measured in the pancreas of intact or CIP rats with or without L-tryptophan pretreatment. Melatonin blood level was measured by RIA. CIP was confirmed by histological examination and manifested as an edema and rises of plasma levels of amylase, lipase and TNF alpha (by 550%, 1000% and 600%). MDA + 4-HNE was increased by 600%, whereas SOD activity was reduced by 75% in the pancreas of CIP rats. All manifestations of CIP were significantly reduced by pretreatment of the rats with L-tryptophan given i.c.v. at doses of 0.2 or 2.0 mg/rat, or by peripheral administration of this amino acid used at dose of 250 mg/kg i.p. In control rats plasma level of melatonin averaged about 40 +/- 2 pg/ml and was not significantly affected by CIP, by central application of L-tryptophan (0.02, 0.2 or 2.0 mg/rat) or by peripheral administration of this melatonin precursor used at doses of 2.5 or 25 mg/kg i.p. Plasma melatonin level was markedly increased by pretreatment of the rats with L-tryptophan given i.p. at dose of 250 mg/kg. We conclude that central administration of melatonin precursor; L-tryptophan, as well as peripheral application of high dose of this melatonin precursor prevented the pancreatic damage produced by CIP. The favorable effect of peripherally administered L-tryptophan could be related to the rise of melatonin plasma level and to pancreatoprotective action of this indoleamine. The beneficial effect of centrally administered L-tryptophan could be mediated through activation of central receptors for locally produced melatonin.

Postoperative immunochemotherapy (BCG + 5-FU) in advanced gastric cancer.

Three hundred and twenty-two patients with locally advanced (stages III and IVA) and disseminated (stage IVB) gastric cancer were included in a randomized trial to assess the effect of immunochemotherapy (BCG and 5-fluorouracil,5-FU). The survival of patients receiving chemoimmunotherapy was compared to chemotherapy (5-FU) or no further treatment (control) groups. Patients with stage III underwent radical surgery (subtotal or total resection), stage IVA palliative resection, while explorative laparotomy or bypass was performed in stage IVB. Patients with stage III and IVA receiving immunochemotherapy had significantly (p less than 0.05) prolonged survival in comparison to chemotherapy or control groups. Prolongation of survival was more pronounced in patients with diffuse type carcinoma than in patients with intestinal type of tumour according to Lauren's classification. The survival of patients receiving chemotherapy was somewhat shorter than that of the control group, but the differences were not statistically significant. There was no effect of either immunochemotherapy or chemotherapy in patients with stage IVB. No serious side effects of immunochemotherapy were noted. These results indicate that immunochemotherapy may be a safe form of adjuvant treatment in patients with operable gastric cancer.