S. Kasai

Successful treatment of a rectal anastomotic stenosis by transanal endoscopic microsurgery (TEM) using the contact Nd:YAG laser

We report the advantage of employing transanal endoscopic microsurgery (TEM) using the contact Nd:YAG laser for the treatment of a rectal anastomotic stenosis. A 72-year-old woman was admitted to our hospital with a postoperative rectal anastomotic stenosis. Twenty months prior to admission, the patient underwent a low anterior resection for the treatment of the rectal cancer using an EEA stapling device. A barium enema and colonoscopy revealed a rectal stenosis, 0.8-cm diameter. This stenosis was at the anastomotic site, approximately 4.0 from the dental line. An endoscopic treatment was performed transanally using the contact Nd:YAG laser. The stenotic rectal wall was fulgurated or vaporized completely. There were no intraoperative or postoperative complications. We concluded that TEM appears to be a safe and minimally invasive procedure. Furthermore, the contact Nd:YAG laser is very effective in treating the gastrointestinal stenotic area. To our knowledge, this is the first successful report of this novel procedure.

Effect of 70% partial hepatectomy on developmental expression of cytochrome P450 IVA1 within intrasplenically transplanted fetal hepatocytes from spontaneously hypertensive rats

Abstract Fetal hepatocytes were harvested at 20 days of gestation from spontaneously hypertensive rats (SHR) and then transplanted into recipient adult SHR spleens. Morphological examination of the recipient spleens revealed that after 4 weeks, large masses of hepatocytes were present in the red pulp, as well as cord-like structures. Immunochemical determinations revealed that cytochrome P450 IVA1 (cytochrome P450 LAω) could be detected without any prior induction. Cytochrome P450 LAω was detected in fetal hepatocyte microsomes from the spleens 6 weeks after fetal hepatocyte transplantation. Cytochrome P450 LAω and peroxisomal acyl CoA oxidase were expressed 6 weeks after transplantation in a 70% hepatectomized host. These results demonstrate that fetal hepatocytes can be successfully transplanted to the spleens of recipient hosts, and that fetal hepatocytes appear to grow and develop functional cytochrome P450 metabolizing systems.

Development of a new membrane-type heated humidifier for laparoscopic surgery.

Background: Recently, several animal studies showed that the core body temperature falls during pneumoperitoneum, and this hypothermia could be prevented by using heated and humidified gas insufflation. However, there are no satisfactory heated humidifiers to meet this purpose. Therefore, we developed a new membrane-type heated humidifier. Materials and methods: The newly developed heated humidifier employs an ion-exchange membrane (Nafion: Du Pont Co. Ltd) tube that passes water selectively in molecular form and a gas compartment is completely separated from distilled water to prevent infection. This humidifier consists of a Nafion tube assembly and a case that includes the heater. A perforated protecting tube is located outside the Nafion tube to prevent direct contact with the Nafion tube when it is assembled. The Nafion tube assembly is inserted in the case, and dry gas flows inside of the Nafion tube. The space between the case and the Nafion tube assembly is filled with distilled water. A heater raises the temperature of the distilled water, and heat and water vapor are transferred to cold and dry gas through the Nafion membrane. Four different types of insufflators were involved in this performance comparison study: a Nafion-based heated and humidified insufflator, a conventional heated insufflator, a conventional heated and humidified insufflator, and a conventional cold and dry insufflator. Temperature and relative humidity were measured once each minute for 15 min, which was repeated four times. Each insufflator was operated at two rates of flow: 5 L/min and 10 L/min. Results: Temperature and humidity of the conventional cold and dry insufflator, the Nafion membrane-type heated and humidified insufflator, the conventional heated insufflator, and the conventional heated and humidified insufflator measured at the distal end of circuit reached 22.0 ± 0.2°C and 0%, 36.7 ± 1.1°C and 100%, 29.0 ± 0.4°C and 0%, and 31.3 ± 0.4°C and 70.5 ± 5.3% in 15 min at 5 L/min flow rates. At 10 L/min flow rates, temperature and humidity were almost the same as those at 5 L/min. The membrane-type heated humidifier demonstrated statistically significant improvement in both the temperature (p < 0.0001) and relative humidity (p < 0.0001) parameters in comparison to the conventional normal, heated, or heated and humidified insufflators at 5 L/min and 10 L/min continuous flow rate in statistics using repeated-measure ANOVA. Conclusion: This newly developed heated humidifier offers the great advantages of maintaining intraabdominal temperature and humidity in comparison to conventional insufflators for laparoscopic surgery.