Impact of specific modes of circumferential resection margin involvement in rectal cancer local recurrence: A retrospective study.

PURPOSE: To compare the local recurrence rate and overall survival between patients with circumferential resection margin (CRM) involvement by direct tumor spread and by a tumor within a lymph node. METHODS: A total of 776 patients diagnosed with rectal cancer underwent rectal resection. Patients with CRM involvement by direct tumor spread were named group A. CRM involvement by tumor within a lymph node formed group B. Patient data, including sex, age, pT, pN, stage I-III versus IV, neoadjuvant radiotherapy, adjuvant chemotherapy, carcinoembryonic antigen, primary tumor location, lymph node retrieval, and need for abdominoperineal resection, were compared between both groups. RESULTS: In total, 10.5% of the patients had CRM involvement. Of these, in 57 cases (7.3%), it was by direct tumor spread and in 19 cases (2.4%) by tumor within a lymph node. Other types of CRM involvement were found in six patients. With a mean follow-up of 32.9 months, 18 patients from group A (31.5%) and one patient from group B (5.2%) suffered a local recurrence. Local recurrence-free survival was significantly higher in patients from group B (P = 0.049). Patients in stage I-III (P = 0.037) and from group B ( P = 0.049) had better overall survival. CONCLUSION: Patients with CRM involvement by tumor within a lymph node have a low risk of local recurrence and better overall survival than patients with CRM involvement by direct tumor spread.

17beta-estradiol prevents oxidative stress and decreases blood pressure in ovariectomized rats.

In this study, we tested whether estrogen deficiency is associated with oxidative stress and decreased nitric oxide (NO) production, which could be responsible for an increased blood pressure in ovariectomized rats. Hemodynamic studies were performed on conscious, chronically instrumented rats. Chronic estrogen replacement on ovariectomized rats lowered blood pressure approximately 13 mmHg, from 119 +/- 3 mmHg in ovariectomized rats to 106 +/- 3 mmHg in ovariectomized-treated rats; it was also accompanied by an increase in cardiac index and vascular conductance, achieving hemodynamic values similar to those shown by sham-operated rats. N(G)-nitro-L-arginine methyl ester administration lowered significantly less the vascular conductance (0.14 +/- 0.01 vs. 0.22 +/- 0.03 and 0.26 +/- 0.01 ml. min(-1). mmHg(-1)/100 g; P < 0.05) in ovariectomized rats than in the sham-operated and estrogen-treated ovariectomized rats, respectively. Estrogen replacement prevented the lower plasma levels of nitrites/nitrates observed in ovariectomized rats. The lower plasma total antioxidant status and reduced thiol groups and the increase in plasma lipoperoxides presented in ovariectomized animals were reestablished with the estrogen treatment. These results show that estrogen administration decreases blood pressure and increases vascular conductance in ovariectomized rats. This effect may be related to an increase in NO synthesis and/or preventing oxidative stress, then improving endothelial function.

Depletion of liver glutathione potentiates the oxidative stress and decreases nitric oxide synthesis in a rat endotoxin shock model.

OBJECTIVE: To verify the effects of liver glutathione depletion on redox status and nitric oxide system in a rat endotoxic shock model. DESIGN: Prospective, randomized, controlled study on rats. SETTING: A cardiocirculatory research laboratory. SUBJECTS: A total of 28 Sprague-Dawley male rats (200-250 g body weight) were divided into four experimental groups. INTERVENTIONS: Arterial blood, liver, and lung samples were taken from each animal under sodium pentobarbital (40 mg/kg i.p.) anesthesia 4 hrs after lipopolysaccharide (LPS group: 5 mg/kg i.p.; n = 7) or vehicle (control group: isotonic NaCl sterile solution i.p.; n = 7) treatments. Phorone (250 mg/kg i.p.) was injected to deplete glutathione in another two experimental groups of rats 30 mins before LPS (phorone+LPS group; n = 7) or vehicle (phorone group; n = 7) treatments, and 4 hrs later the same samples as in LPS and control groups were taken under anesthesia. MEASUREMENTS AND MAIN RESULTS: Compared with the control group, the LPS group presented higher plasma concentration of end products of nitric oxide metabolism nitrites/nitrates, higher lung activity of inducible nitric oxide synthase, and oxidative stress defined by increased plasma concentration of the lipid peroxides malonaldehyde and 4-hydroxynonenal, and decreased plasma total antioxidant capacity. Treatment with phorone depleted liver glutathione (80% to 90%). In the liver glutathione-depleted animals, the oxidative stress induced by LPS was potentiated and blunted the increases in inducible nitric oxide synthase and plasma nitrites/nitrates. CONCLUSION: These results show that depletion of the liver glutathione increases the oxidative stress and decreases nitric oxide synthesis of LPS-induced shock in rats.