AIM: To investigate the number, size, and status of lymph nodes within the mesorectum and to explore the prognostic significance of lymph node micrometastases in patients with rectal cancer. METHODS: Thirty-one patients with rectal cancer undergone total mesorectal excision between October 2001 and October 2002 were included. Mesorectal nodes retrieved from the resected specimens were detected with a combination of haematoxylin and eosin (HE) staining and immunohistochemistry (IHC). The relations between lymph node metastases, micrometastases and postoperative recurrence were analyzed. RESULTS: A total of 548 lymph nodes were harvested, with 17.7

AIM: To investigate the fluid shear stress induced changes of [Ca2+]i in neutrophils in pancreatic microcirculation of experimental acute pancreatitis (AP). METHODS: Wistar rats (n=36) were randomized into three roups. A model of AP was established by subcutaneous injection of caerulein. Low-shear 30 viscometer was used to provide steady fluid shear stress on separated neutrophils. The mean fluorescent intensity tested by flow cytometry was used as the indication of [Ca2+]i quantity. RESULTS: Under steady shear, cytosolic [Ca2+]i showed biphasic changes. The shear rate changed from low to high, [Ca2+]i in different groups decreased slightly and then increased gradually to a high level (P<0.05). A close correlation was observed between the cytosolic [Ca2+]i level and the alteration of fluid shear stress in regional microcirculation of AP. CONCLUSION: The increase of [Ca2+]i is highly related to the activation of neutrophils, which contributes to neutrophil adhesion to endothelium in the early phase of AP. The effect of fluid shear stress on [Ca2+]i may play a crucial role in pancreatic microcirculatory failure of AP.

AIM: To assess the microscopic spread of low rectal cancer in mesorectum regions to provide pathological eviden ce for the necessity of total mesorectal excision (TME). METHODS: A total of 62 patients with low rectal cancer underwent low anterior resection and TME, surgical specimen s were sliced transversely on the serial embedded blocks at 2.5 mm interval, and stained with hematoxylin and eosin (HE). The mesorectum on whole-mount sections was divided into three regions: outer region of mesorectum (ORM), middle region of mesorectum (MRM) and inner region of mesorectum (IRM). Microscopic metastatic foci were investigated microscopically on the sections for the metastatic mesorectal regions, frequency, types, involvement of lymphatic vessels and correlation with the original rectal cancer. RESULTS: Microscopic spread of the tumor in mesorectum and ORM was observed in 38.7% (24/62) and 25.8% (16/62) of the patients, respectively. Circumferential resection margin (CRM) with involvement of microscopic metastatic foci occurred in 6.5% (4/62) of the patients, and distal mesorectum (DMR) involved was 6.5% (4/62) with the spread extent within 3 cm of low board of the main lesions. Most (20/24) of the patients with microscopic metastasis in mesorectum were in Dukes C stage. CONCLUSION: Results of the present study support that complete excision of the mesorectum without destruction of the ORM is essential for surgical management of low rectal cancer, an optimal DMR clearance resection margin should be no less than 4 cm, further pathologic assessment of the regions in extramesorectum in the pelvis is needed.

AIM: To assess the feasibility and efficacy of laparoscopic total mesorectal excision (LTME) of low rectal cancer with preservation of anal sphincter. METHODS: From June 2001 to June 2003, 82 patients with low rectal cancer underwent laparoscopic total mesorectal excision with preservation of anal sphincter. The lowest edge of tumors was below peritoneal reflection and 1.5-7 cm from the dentate line (1.5-5 cm in 48 cases, 5-7 cm in 34 cases). RESULTS: LTME with anal sphincter preservation was performed on 82 randomized patients with low rectal cancer, and 100% sphincter preservation rate was achieved. There were 30 patients with laparoscopic low anterior resection (LLAR) at the level of the anastomosis below peritoneal reflection and 2 cm above from the dentate line; 27 patients with laparoscopic ultralow anterior resection (LULAR) at the level of anastomoses 2 cm below from the dentate line; and 25 patients with laparoscopic coloanal anastomoses (LCAA) at the level of the anastomoses at or below the dentate line. No defunctioning ileostomy was created in any case. The mean operating time was 120 minutes (ranged from 110-220 min), and the mean operative blood loss was 20 mL (ranged from 5-120 mL). Bowel function was restored and diet was resumed on day 1 or 2 after operation. The mean hospital stay was 8 days (ranged from 5-14). Postoperative analgesics were used in 45 patients. After surgery, 2 patients had urinary retention, one had anastomotic leakage, and another 2 patients had local recurrence one year later. No interoperative complication was observed. CONCLUSION: LTME with preservation of anal sphincter is a feasible, safe and minimally invasive technique with less postoperative pain and rapid recovery, and importantly, it has preserved the function of the sphincter.