Laparoscopic versus conventional open resection of rectal carcinoma:A clinical comparative study

AIM:To evaluate the feasibility of laparoscopic resection of rectal carcinoma and to compare the short-term outcome of laparoscopic procedure with conventional open surgery for rectal cancer. METHODS:Thirty-eight patients with rectal cancer were included in a prospective non-randomized study.The patients were assigned to laparoscopic (n=18) or open (n=18) colorectal resection.Case selection,surgical technique,and clinical and pathological results were reviewed. RESULTS:The operative time was longer in laparoscopic resection group (LAP) than in open resection group (189±18 min vs 146±22 min,P7<0.05).Intraoperative blood Loss and postoperative complications were less in LAP resection group than in open resection group.An earlier return of bowel motility was observed after laparoscopic surgery.The overall postoperative morbidity was 5.6% in the LAP resection group and 27.8% in open resection group (P<0.05).No anastomotic leakage was found in both groups. The pathologic examination showed that the length of the resected specimen,the mean number of harvested lymph nodes in laparoscopic resection group were comparable to those in open resection group. CONCLUSION:Laparoscopic total mesorectal excision (TME) for rectal cancer is a feasible but technically demanding procedure.The present study demonstrates the safety of the procedure,while oncologic results are comparable to the open surgery,with a favorable short-term outcome.

Gastrointestinal decompression after excision and anastomosis of lower digestive tract

AIM: To discuss the clinical significance of postoperative gastrointestinal decompression in operation on lowerdigestive tract.METHODS: Three hundred and sixty-eight patients with excision and anastomosis of lower digestive tract were divided into two groups, i.e. the group with postoperative gastrointestinal decompression and the group withoutposto perative gastrointestinal decompression. Clinical therapeutic outcome and incidence of complication were compared between two groups. Furthermore, an investigation on application of gastrointestinal decompression was carried out among 200 general surgeons.RESULTS: The volume of gastric juice in decompression group was about 200 mL every day after operation. Both groups had a lower girth before operation than every day after operation. No difference in length of the first passage of gas by anus and defecation after operation was found between two groups. The overall incidence of complications was obviously higher in decompression group than in non-decompression group (28% vs 8.2%,P<0.001). The incidence of pharyngolaryngitis was up to 23.1%. There was also no difference between two groups regarding the length of hospitalization after operation.The majority (97.5%) of general surgeons held that gastrointestinal decompression should be placed till passage of gas by anus, and only 2.5% of surgeons thought that gastrointestinal decompression should be placed for 2-3 d before passage of gas by anus. Nobody (0%) deemed it unnecessary for placing gastrointestinal compression after operation.CONCLUSION: Application of gastrointestinal decompression after excision and anastomosis of lower digestive tract cannot effectively reduce gastrointestinal tract pressure and has no obvious effect on preventing postoperative complications. On the contrary, it may increase the incidence of pharyngolaryngitis and other complications. Therefore, it is more beneficial to the recovery of patients without undergoing gastrointestinal decompression.

Effects of 7.5% hypertonic saline on fluid balance after radical surgery for gastrointestinal carcinoma

AIM: To investigate the effects of 7.5% hypertonic saline on positive fluid balance and negative fluid balance, after radical surgery for gastrointestinal carcinoma. METHODS: Fifty-two patients with gastrointestinal carcinoma undergoing radical surgery were studied. The patients were assigned to receive either Ringer lactate solution following 4 mL/kg of 7.5% hypertonic saline (the experimental group, n = 26) or Ringer lactate solution (the control group, n = 26) during the early postoperative period in SICU. Fluid infusion volumes, urine outputs, fluid balance, body weight change, PaO2/FiO2 ratio, anal exhaust time as well as the incidence of complication and mortality were compared between the two groups. RESULTS: Urine outputs on the operative day and the first postoperative day in experimental group were significantly more than in control group (P<0.000001, P=0.000114). Fluid infusion volumes on the operative day and the first postoperative day were significantly less in experimental group than in control group (P= 0.000042, P= 0.000415). The volumes of the positive fluid balance on the operative day and during the first 48 h after surgery, in experimental group, were significantly less than in control group (P<0.000001). Body weight gain post-surgery was significantly lower in experimental group than in control group (P<0.000001). The body weight fall in experimental group occurred earlier than in control group (P<0.000001). PaO2/FiO2 ratio after surgery was higher in experimental group than in control group (P= 0.000111). The postoperative anal exhaust time in experimental group was earlier than in control group (P= 0.000006). The overall incidence of complications and the incidence of pulmonary infection were lower in experimental group than in control group (P= 0.0175, P= 0.0374). CONCLUSION: 7.5% hypertonic saline has an intense diuretic effect and causes mobilization of the retained fluid, which could reduce fluid infusion volumes and positive fluid balance after radical surgery for gastrointestinal carcinoma, as well as, accelerate the early appearance of negative fluid balance after the surgery, improve the oxygen diffusing capacity of the patients' alveoli, and lower the overall incidence of complications and pulmonary infection after the surgery.

Expression of thymidine phosphorylase by macrophages in colorectal cancer tissues

AIM:To detect the thymidine phosphorylase (dThdPase) expression in human colorectal cancer tissues and cells.METHODS:Forty specimens resected from patients with colorectal cancer were immunohistochemically stained by 654-1, anti-dThdPase monoclonal antibody, PG-M1,anti-macrophage marker CD68 monoclonal antibody.Morphometrical analysis and positive cell counting were performed. In 27 of 40 specimens, dThdPase activity was also assayed by HPLC. Otherwise, the dThdPase level was measured by ELISA in 6 colorectal cancer cell lines, LS174T,Clone A, Colo320, CX-1, Lovo, and MIP101, as well as in 2 macrophage-like cell lines, THP-1 and U937.RESULTS:dThdPase activity was significantly increased in cancer tissues compared with adjacent normal tissue (P<0.01).In immunohistochemical analysis, it was confirmed that most cells expressed dThdPase were the stromal cells surrounding cancer nests or along the invasive margin of cancer. Based on their morphometrical characteristics, we found that most of them were tumor-associated macrophages (TAMs). The number of dThdPase-positive stromal cells was significantly correlated with the number of CD68-positive macrophages (r=0.76, P<0.0001). By ELISA,18.2 unit/mg and 19.3 unit/mg of dThdPase protein were detected in THP-1 and U937,but only little was detected in 6 colorectal cancer cell lines.CONCLUSION:The present data suggest that dThdPase expression is seldom detected in colorectal carcinoma cells.TAM is the most important source of dThdPase in colorectal cancer tissues.

Effect of retinoic acid on cell proliferation kinetics and retinoic acid receptor expression of colorectal mucosa

AIM: To investigate the effect of retinoic acid (RA) on cell proliferation kinetics and retinoic acid receptor (RAR)expression of colorectal mucosa.METHODS:One hundred sixty healthy male Wistar rats were randomly divided into 4 groups. Rats in groups Ⅰ and Ⅱ were subcutaneously injected with dimethylhydrazine (DMH) (20 mg/kg, once a week,) for 7 to 13 weeks, while groups Ⅲ and Ⅳ were injected with normal saline. Rats in groups Ⅱ and Ⅲ were also treated with RA (50 mg/kg,every day, orally) from 7th to 15th week, thus group Ⅳ was used as a control. The rats were killed in different batches.The expressions of proliferating cell nuclear antigen (PCNA),nucleolar organizer region-associated protein (AgNOR) and RAR were detected.RESULTS: The incidence of colorectal carcinoma was different between groupsⅠ(100 %) and Ⅱ (15 %) (P＜0.01).The PCNA indices and mean AgNOR count in group Ⅱ were significantly lower than those in group Ⅰ(F=5.418 and 4.243,P＜0.01). The PCNA indices and mean AgNOR count in groups Ⅰ and Ⅱ were significantly higher than those in the groups Ⅲ and Ⅳ (in which carcinogen was not used) (F=5.927and 4.348, P＜0.01). There was a tendency in group Ⅰ that the longer the induction with DMH the higher PCNA index and AgNOR count expressed (F=7.634 and 6.826, P＜0.05).However, there was no such tendency in groups Ⅱ, Ⅲ and Ⅳ(F=1.662 and 1.984, P＞0.05). The levels of RAR in normal and cancerous tissues in groups treated with RA were significantly higher than those in groups not treated with RA (F=6.343 and 6.024, P＜0.05).CONCLUSION: RA decreases the incidence of colorectal carcinoma induced by DMH. Coiorectal cancer tissue is associated with abnormal expression of PCNA, AgNOR and RAR. RA inhibits the expression of PCNA and AgNOR, and increases RAR concentration in colorectal tissues.

Pathological study of distal mesorectal cancer spread to determine a proper distal resection margin

AIM: Local recurrence after curative surgical resection for rectal cancer remains a major problem. Several studies have shown that incomplete removal of cancer deposits in the distal mesorectum contributes a great share to this dismal result. Clinicopathologic examination of distal mesorectum in lower rectal cancer was performed in the present study to assess the incidence and extent of distal mesorectal spread and to determine an optimal distal resection margin in sphincter-saving procedure.METHODS: We prospectively examined sepecimens from 45 patients with lower rectal cancer who underwent curative surgery. Large-mount sections were performed to microscopically observe the distal mesorectal spread and to measure the extent of distal spread. Tissue shrinkage ratio was also considered. Patients with involvement in the distal mesorectum were compared with those without involvement with regard to clinicopathologic features.RESULTS: Mesorectal cancer spread was observed in 21patients (46.7%), 8 of them (17.8%) had distal mesorectal spread. Overall, distal intramural and/or mesorectal spreads were observed in 10 patients (22.2%) and the maximum extent of distal spread in situ was 12 mm and 36 mm respectively. Eight patients with distal mesorectal spread showed a significantly higher rate of lymph node metastasis compared with the other 37 patients without distal mesorectal spread (P = 0.043).CONCLUSION: Distal mesorectal spread invariably occurs in advanced rectal cancer and has a significant relationship with lymph node metastasis. Distal resection margin of 1.5 cm for the rectal wall and 4 cm for the distal mesorectum is proper to those patients who are arranged to receive operation with a curative sphincter-saving procedure for lower rectal cancer.

Mutation in D-loop region of mitochondrial DNA in gastric cancer and its significance

AIM:To investigate the mutation in D-loop region of mitochondrial DNA in gastric cancer and its influence on the changes of reactive oxygen species (ROS) and cell cycle. METHODS: The D-loop region was amplified by PCR and sequenced.Reactive oxygen species and cell cycle were detected by flow cytometry in 20 specimens from gastric cancer and adjacent normal tissues.According to the sequence results,gastric cancer tissue was divided into mutation group and control group.Reactive oxygen species,apoptosis and proliferation in the two groups were compared. RESULTS:Among the 20 gastric cancer specimens, 18 mutations were identified in 7 patients,the mutation rate being 35%.There were four microsatellite instabilities in the mutations. No mutation was found in the adjacent tissues. Reactive oxygen species,apoptosis,and proliferation in the mutation group were all significantly higher than those in control group. CONCLUSION: Mutation in D-loop region plays a role in the genesis and development of gastric cancer.

Morphologic and biomechanical changes of rat oesophagus in experimental diabetes

AIM: To study morphologic and biomechanical changes of oesophagus in diabetes rats.METHODS: Diabetes was induced by a single injection of streptozotocin (STZ). The type of diabetes mellitus induced by parenteral STZ administration in rats was insulin-dependent (type I). The samples were excised and studied in vitro using a self-developed biomaterial test machine.RESULTS: The body mass was decreased after 4 d with STZ treatment. The length of esophagus shortened after 4, 7,14 d. The opening angle increased after 14 d. The shear,longitudinal and circumferential stiffness were obviously raised after 28 d of STZ treatment.CONCLUSION: The changes of passive biomechanical properties reflect intra-structural alteration of tissue to a certain extent. This alteration will lead to some dysfunction of movement. For example, tension of esophageal wall will change due to some obstructive disease.

Differences in platelet endothelial cell adhesion molecule-1 expression between peripheral circulation and pancreatic microcirculation in cerulein-induced acute edematous pancreatitis

AIM: To investigate the changes of platelet endothelial cell adhesion molecule-1 (PECAM-1) expression on polymorphonuclear leukocytes (PMNs) in peripheral circulation and pancreatic microcirculation in cerulein-induced acute edematous pancreatitis (AEP).METHODS: Fifty Wistar rats were randomly divided into control group (n=10) and AEP group (n=40). A model of AEP was established by subcutaneous injection of cerulein 5.5 and 7.5 μg/kg at 0 and 1 h after the beginning of experiment respectively. PECAM-1 expression on PMNs from splenic vein and inferior vena cava was determined by RT-PCR at mRNA level and determined by flow cytometry at protein level.RESULTS: In experimental rats, an increased PECAM-1mRNA expression was seen from 4 to 8 h of AEP in peripheral circulation (0.77±0.25%, 0.76±0.28%, 0.89±0.30%,1.00±0.21% ), while in pancreatic microcirculation,expression decreased from 2 h and reached the lowest level at 6 h of AEP (0.78±0.29%, 0.75±0.26%, 0.62±0.28%,0.66±0.20%). There were significant differences at 8-h time point of AEP between peripheral circulation and pancreatic microcirculation (1.00±0.21% vs0.66±0.20%, P＜0.05).Meanwhile,the difference at protein level was also found.CONCLUSION: A reverse expression of PECAM-1 on PMNs was found between peripheral circulation and pancreatic microcirculation, suggesting that inhibition of PECAM-1expression may improve the pathological change of AEP.

Effect of local CTLA4Ig gene transfection on acute rejection of small bowel allografts in rats

AIM:To evaluate the local expression of CTLA4Ig gene in small bowels and its effect on preventing acute rejection of the small bowel allografts.METHODS:Groups of Wistar rats underwent heterotopic small bowel transplantation from SD rats.The recipients were randomly divided into experimental group (allografts were transfected with CTLA4Ig gene) and control group (non CTLA4Ig gene transfected).In the experimental group, the donor small bowels were perfused ex vivo with CTLA4Ig cDNA packaged with lipofectin vector via intra-superior mesenteric artery before transplantation, and the CTLA4Ig expression in the small bowel grafts post-transplantation was assessed by immunohistology. On d 3, 7 and 10 post-transplantation,the allografts in each group were harvested for the examination of histology and detection of apoptosis.RESULTS:Small bowel allografts treated with CTLA4Ig cDNA showed abundant CTLA4Ig expression after transplantation.Acute rejection of grade I on d 7 and grade Ⅱ on d 10 after transplantation was noticed in the control allografts,and a dramatically increased number of apoptotic enterocytes in parallel to the progressive rejection could be recognized.In contrast,the allografts treated with CTLA4Ig cDNA showed nonspecific histological changes and only a few apoptotic enterocytes were found after transplantation.CONCLUSION: Local CTLA4Ig gene transfection of small bowel allograft is feasible, and the local CTLA4Ig expression in the allograft can prevent acute rejection after transplantation.

Prolonged Small Bowel Allografts Survival by CTLA4Ig Gene Transfection in Rats

Objective: To evaluate the local expression of CTLA4Ig gene in small intestines and its effect on prolonging survival time of the small bowel allografts. Methods: The donor small bowels were perfused ex vivo with CTLA4Ig cDNA reconstructed plasmid packaged with lipofectin vector via intra-superior mesenteric artery before transplantation. The CTLA4Ig transgene expression in the small bowel allografts was assessed by immunohistology and RT-PCR after transplantation. Results: Immunohistology and RT-PCR demonstrated expression of CTLA4Ig transgene in the allografts at least for 28 d after transplantation. Eleven cases of the 18 small bowel allografts that received CTLA4Ig gene transfection survived more than 90 d in the recipients. Conclusion: A single ex vivo intra-superior mesenteric artery infusion of CTLA4Ig cDNA reconstructed plasmid packaged with lipofectin induced efficient transduction of the small intestine, and the transfected small bowel allografts could survivor longer in nonimmunosupression rats.

Mutations in the D-loop region of mitochondrial DNA in gastric cancer

Objective: To investigate the mutati ons in the D-loop region of mitochondrial DNA (mtDNA) in gastric cancer. Methods: The mtDNA of D-loop region was amplified by PCR and sequence d in 20 samples from gastric cancer tissue and adjacent normal membrane. Results: There were 7/20(35%) mutations in the mtDNA of D-loop regio n in gastric cancer patients. There were four microsatellite instabilities among the 18 mutations. Nine new polymorphisms were identified in 20 patients. Conclusion: The mtDNA of D-loop region might be highly polymorphoric and the mutation rate is high in patients with gastric cancer.