Takao Ichihara

Glut1 expression in T1 and T2 stage colorectal carcinomas: its relationship to clinicopathological features.

Glucose uptake is mediated by glucose transporter (Glut) proteins, which exhibit altered expression in a variety of malignant neoplasms. Glut1 expression is thought to be a potential marker for malignant transformation. The aim of the present study was to investigate the expression of Glut1 protein in colorectal adenomas, T1 and T2 stage carcinomas. Immunohistochemical detection of Glut1 protein was examined in 141 formalin-fixed and paraffin-embedded colorectal tumour specimens (57 adenomas, 84 carcinomas). The degree of Glut1 immunostaining of a specimen was graded according to the proportion of Glut1-positive cells in it; absent (positive cells are 0%), weakly positive (less than 10%), moderately positive (10-50%), and strongly positive (more than 50%). Glut1 expression was present in 18% of the adenomas with low-grade dysplasia, and in 63% of the adenomas with high-grade dysplasia. The positivity in such lesions was usually weak, but was moderate in 8% of the adenomas with high grade dysplasia. For the carcinomas, there were significant correlations between Glut1-positivity and depth of invasion (T1 45% versus T2 74%, P<0.01), histological differentiation (well 49% versus moderately to poorly 74%, P< 0.05) and morphological type (polypoid 42% versus depressed 73%, P< 0.05), if the cut-off value was set at 10% of cells. In conclusion, we clarified the relationship between Glut1 expression and clinicopathological features in T1 and T2 stage colorectal carcinomas, and our results suggested a high malignant potential of the depressed-type carcinoma.

Comparative study of electrothermal bipolar vessel sealer and ultrasonic coagulating shears in laparoscopic colectomy

BackgroundAs an alternative to suture ligatures of the vessels, an electrothermal bipolar vessel sealer (EBVS) was recently developed. Meanwhile, ultrasonic coagulating shears (UCS) have been widely used clinically to provide hemostatic cutting in laparoscopic procedures. We conducted a comparative study to investigate the relative advantages of these two instruments.MethodsThe study included 30 patients with colon cancer who underwent laparoscopic colectomy using either the EBVS or the UCS. We performed a comparative analysis of the instruments by viewing videotapes showing their application in laparoscopic transverse colectomy and sigmoidectomy.ResultsAverage patient age was 71.6 ± 1.4 years. Average hospital stay was 14.2 ± 1.0 days. There were no statistical differences between the groups in age and hospital stay. The incidence of rebleeding was significantly lower in the EBVS group than in the UCS group for both surgical procedures (0.3 vs 1.2 in transverse colectomy, 0.3 vs 2.0 in sigmoidectomy, respectively). In addition, the required time for mesocolon dissection was also significantly shorter when the EBVS was used in both laparoscopic transverse colectomy and sigmoidectomy (7.9 vs 18.4, 15.0 vs 27.6, respectively).ConclusionThe use of the EBVS will enable surgeons to reduce the total operating time for laparoscopic colectomy.

Study of 16,16-Dimethyl Prostaglandin E2 for Prevention of Stress Ulcer after Hepatectomy of Experimental Cirrhotic Liver and Its Influence on Hepatic Regeneration

The influence of 16,16-dimethyl prostaglandin E2 (16,16-dm PGE2; an agent used for the prevention of stress ulcer after hepatectomy of the cirrhotic liver) on liver regeneration after hepatectomy was studied in rats. The following results were obtained. Ulceration after the stress of 6 h of water immersion was markedly suppressed in rats treated with 30 r/kg of 16,16-dmPGE2 as compared with the untreated controls. In animals that received hepatectomy alone, the gastric pH and gastric mucosal blood flow showed significant reduction from the preoperative levels. In animals that received hepatectomy plus 16,16-dmPGE2 treatment the postoperative reduction in the gastric pH and gastric mucosal blood flow was suppressed, suggesting the effectiveness of 16,16-dmPGE2 treatment in the prevention of stress ulcer after hepatectomy of the cirrhotic liver. The 3H-thymidine uptake percentage and thymidine activity 24 h after hepatectomy and the DNA content 30 h after hepatectomy were significantly higher in animals treated with 16,16-dmPGE2 than in the untreated controls. In animals that were treated intraperitoneally with 50 mg/kg of indomethacin 6 h before hepatectomy the mitotic index 30 h after hepatectomy was markedly lower than that in untreated controls. This indomethacin-induced reduction in the mitotic index tended to be normalized by treatment with 16,16-dmPGE2. These results suggest that 16,16-dmPGE2 treatment effectively prevents stress ulcer and favorably affects hepatic regeneration after hepatectomy of the cirrhotic liver.

Laparoscopic lower anterior resection is equivalent to laparotomy for lower rectal cancer at the distal line of resection

BACKGROUND Procedures that involve resection of the distal rectum challenge the current limitations of laparoscopic technology, because of lack of compact articulating stapling instruments. METHOD We improve the procedure with the aid of a Lap disk, an abdominal wall sealing device that was developed for hand-assisted manipulation. A linear stapler capable of changing its stop angle is inserted through the disk, and the rectum is transected by the disk during a second pneumoperitoneum. RESULTS The transection line becomes equivalent to that obtained with laparotomy. CONCLUSION This new technique made laparoscopic lower anterior resection possible to transect the lower rectum in the same way as is done with laparotomy.

Inhibitory Effect of Peptide YY on Gastric Acid Output in Rats

The administration of peptide YY (PYY: 0.8, 1.6 and 3.2 nmol/kg/h, i.v.) to fasting rats inhibited not only baclofen (2 mg/kg, s.c.)-stimulated gastric acid output and gastric mucosal blood flow, but also pentagastrin (8 micrograms/kg/h, i.v.)-stimulated gastric acid output. PYY (3.2 nmol/kg/h) reduced baclofen-induced acid output more than pentagastrin-induced acid output, i.e., by 61.8 +/- 11.5% compared to 35.3 +/- 8.2%. PYY inhibited acetylcholine (ACh) release from cholinergic nerve endings of gastric body evoked by electrical transmural stimulation (ETS: 1 msec, 10 V, 3 Hz, 30 sec) by 47.2 +/- 3.5%. The mechanism of the inhibitory effect of PYY on gastric acid output seems to involve decreased gastric mucosal blood flow and reduced ACh release from cholinergic nerves.

Comparison of intestinal transit recovery between laparoscopic and open surgery using a rat model

Background: After laparoscopic surgery (LS), patients show faster recovery of intestinal transit than after conventional open surgery (OS). To prove the mechanism of this advantage, we compared the recovery of intestinal transit using steel carbon balls. Methods: Rats underwent either open laparotomy or were insufflated with carbon dioxide followed by the administration of steel balls (0.6 mm). An abdominal radiograph was taken 12 h after the operation. Compliance of the intestinal walls was analyzed with a computer-driven barostat device. Results: An abdominal radiograph of 12 h after administration of the steel carbon balls showed the balls scattered in the small and large intestine of the LS patients, whereas they remained mostly in the stomach of the OS patients. Compliance of the intestinal walls was sustained at approximately 100 µl/mmHg in the LS patients, whereas it dropped to 94 µl/mmHg in the OS patients with the increase in balloon pressure. Histologically, the extent of serosal edema was more severe in the OS than in the LS patients. In terms of intestinal transit and irritation LS has advantage over OS. Conclusions: Intestinal transit recovery, as measured by the migration of steel carbon balls, is faster in LS, and gastric emptying is slow in OS.

The mechanism of acute gastric ulcer after induced hemorrhagic shock.

Changes in gastric mucosal blood flow were investigated for their relationship to gastric mucosal prostaglandin E2 (PGE2) and noradrenaline (NA) in rats with hemorrhagic shock. The results were as follows: 1) Gastric mucosal blood flow and NA decreased after hemorrhage. Gastric mucosal PGE2 initially increased after exsanguination and then markedly decreased. 2) Administration of NA before hemorrhage resulted in an increase of PGE2. However, the PGE2 value for animals receiving NA after hemorrhage was not different from that of non-NA-treated group. 3) Pre-treatment with PGE2 suppressed the reduction in both gastric mucosal blood flow and NA and the development of ulcer. These results suggest that the increase in gastric mucosal PGE2 in the early stage of shock might represent a phenomenon of adaptation by the adrenergic activation, and the decrease in PGE2 in the late stage might result from impaired synthesis of PGE2 due to persistent hypoxia and might be one of the possible factors in ulcer formation.

Role of platelet activating factor on severity of ischemic colitis

PURPOSE: Ischemic colitis develops after a sudden decrease in colonic blood supply and has a variety of clinical manifestations. The aim of this study was to assess the role of platelet activating factor in the pathogenesis of ischemic colitis with use of the platelet activating factor antagonist TCV-309. METHODS: Rats were randomly divided into four groups. Rats in Group RV underwent ring attachment around the rectum to induce partial obstruction and ligation of the marginal vessels of the left colon. As control, rats in Group R underwent the ring attachment and rats in Group V underwent the vascular ligation. Rat in Group C underwent sham operation. The effects of TCV-309 on lesion formation in the colon were evaluated. Thiobarbituric acid reactant level was determined in colonic mucosa, and the incidence and severity of ischemic lesions were also determined. RESULTS: Lesions of colitis were frequently observed in Group RV. TCV-309 did not prevent lesion formation, nor did it suppress the increase in thiobarbituric acid reactant level in Group RV. However, TCV-309 mitigated the severity of the lesion. CONCLUSIONS: Partial obstruction of the colon tends to induce ischemic colitis, and additional ischemia completes lesion formation. Platelet activating factor may play a role in the progression of ischemic lesions.