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Biomedical subjects

S Maetani

Publications and source records attributed to S Maetani.

69 records · Page 4Linked to original sources
PubMed1978

Carcinoma arising in a congenitally dilated biliary tract. Report of a case and review of the literature.

A case of carcinoma arising in a congenitally dilated biliary tract is reported. Forty-seven cases in which congenital dilatation of the biliary tract was associated with carcinoma were found in the world literature and analyzed. The association of carcinoma with congenital biliary ductal dilatation was found to be higher than previously recognized. Carcinoma may arise in any cystic portion, extrahepatic or intrahepatic. If technically safe and feasible, primary excision of the choledochal cyst is advisable, to prevent the risk of later malignant change in the unexcised cyst.

Adenocarcinoma, Papillary↗
PubMed1975

Portal hypertension following exchange blood transfusion with complications of Listeria meningitis.

A male infant, 17 months, developed portal hypertension after two exchange blood transfusions and a prolonged umbilical vein catheterization during the neonatal period. Clinical course was characterized by an early onset of splenomegaly and after a latent period of time by a massive melena and hematemesis precipitated by Listeria meningitis. Treatment for portal hypertension consisted of splenectomy and proximal gastric devascularization. The importance of proper positioning of the catheter and avoidance of extended catheterization is recommended.

Ampicillin↗
PubMed1974

Prognostic significance of serum albumin urea ratio in suture line leakage of the alimentary tract.

Prognostic significance of postoperative changes in serum albumin and urea concentrations as well as their ratio was statistically evaluated in 73 patients with suture line leakage of the abdominal alimentary tract. Increase in serum urea was associated with poor prognosis regardless of the site of leakage. Although the serum albumin concentration was poorly correlated to prognosis, its ratio to serum urea was of more prognostic significance than the urea value alone. When the ratio of the serum albumin nitrogen to the urea nitrogen fell below 10, there was a sharp rise in mortality as well as in morbidity, associated with poor local defense reaction, high incidence of spreading peritonitis, severe systemic complications, and decreased tolerance to tube feeding as well as parenteral hyperalimentation. A special therapeutic policy was suggested for the management of leakage in patients with critically low albumin/urea ratios.

Adult↗
PubMedDate not supplied

A newly developed three-layer agarose microcapsule for a promising biohybrid artificial pancreas: rat to mouse xenotransplantation.

We examined the effectiveness of an improved version of a three-layer agarose microcapsule in islet xenotransplantation. The microcapsule is composed of a mixture of 5% agarose and 5% polystyrene sulfonic acid. The other two outer layers are polybrene and carboxymethyl cellulose. The agarose/polystyrene sulfonic acid membrane is for the purpose of immunoisolation, suppression of complement activity and reinforcement of the microcapsule. The polybrene layer suppresses the polystyrene sulfonic acid leakage by forming a polyionic complex at the surface of the agarose/polystyrene sulfonic acid membrane. The outermost layer, a carboxymethyl cellulose coating, improves the biocompatibility of the microcapsule. In vitro static incubation study showed that the insulin secretion from rat islets in microcapsules in response to 16.7 mM glucose stimulation was more than four times higher than that on 3.3 mM glucose stimulation (n = 8). In an in vivo study, 500 rat islets in microcapsules were xenogenically implanted in the abdominal cavity of mice with streptozotocin-induced diabetes. The graft survival times ranged from 2 to 5 mo, the average being 75 days (n = 5). Our results demonstrate that the improved version of the three-layer agarose microcapsule can effectively prolong the xenograft survival time without employing immunosuppressants, suggesting that this microcapsule could provide a promising biohybrid artificial pancreas for future clinical applications.

Animals↗
PubMedDate not supplied

Application of a novel B cell line MIN6 to a mesh-reinforced polyvinyl alcohol hydrogel tube and three-layer agarose microcapsules: an in vitro study.

This study examines the function of a novel B cell line (MIN6) enclosed in hybrid bioartificial pancreas with mesh-reinforced polyvinyl alcohol hydrogel tube (MRPT) or with improved, three-layer agarose microcapsules. MIN6 was established from insulinomas obtained by targeted expression of the simian virus 40 T-antigen gene in transgenic mice. MIN6 retains the ability to secrete insulin in response to physiological glucose concentrations. The MRPT and the three-layer agarose microcapsules, which were developed to act as an artificial pancreas, were readily permeated by insulin, glucose, and other nutrients. Both can immunoisolate enclosed MIN6 cells from the recipient's humoral and cellular immunosystems, which causes a xenogeneic rejection response. MIN6 cells (5.0 x 10(6) or 1.5 x 10(6)) were enclosed in MRPT or in a hundred three-layer microcapsules and subjected to an in vitro perifusion study or a static incubation study to observe the insulin release from each bioartificial pancreas in response to glucose stimulation. In vitro study revealed that the insulin secretion in response to 16.7 mM glucose stimulation was twice that with 3.3 mM glucose stimulation with both MRPT and the three-layer agarose microcapsules. The present study demonstrates that MIN6 effectively functions as a bioreactor for the hybrid bioartificial pancreas. The application of MIN6 cells to the hybrid bioartificial pancreas may offer a solution to the current serious dearth of organs.

Animals↗
PubMedDate not supplied

Novel control system for blood glucose using a model predictive method.

We developed a novel blood glucose control system, using a model predictive method, to achieve optimal control of the blood glucose level in severely diabetic or pancreatectomized patients. This system is designed to predict glucose level changes in advance, considering delayed response time and the administered doses of insulin. This method is also designed to calculate the most appropriate insulin infusion rate by considering differences in individual response to insulin. In this study, we compared our system with a conventional proportional and differential controller (PD controller) to determine whether the new system could regulate the glucose level efficiently in pancreatectomized dogs. The model predictive control method resulted in a significant reduction of mean insulin infusion rate compared with the conventional PD controller (0.71 mU/kg per min vs. 1.81 mU/kg per min, p = 0.0005), when the glucose level in both methods reached the planned target level (100 mg/dl). The new system also tended to have a reduced mean glucose infusion rate for compensating for overshooting of the glucose level compared with the PD controller (0.7 mg/kg per min vs. 1.1 mg/kg per min, p = 0.16). These results indicate that the new system should be a useful tool for regulating the glucose level in severely diabetic patients.

Animals↗
PubMedDate not supplied

Expression of insulin-like growth factor-2 can predict the prognosis of human colorectal cancer patients: correlation with tumor progression, proliferative activity and survival.

Expression of insulin-like growth factor-2 (IGF-2) has been reported in tissue specimens and cell lines of human colorectal cancers. However, the effects of IGF-2 in colorectal cancer patients are not well known. In this study, IGF-2 staining was performed on tissue samples from 92 patients with colorectal cancer, and the relationship of IGF-2 staining to clinicopathological variables, proliferating cell nuclear antigen (PCNA) staining and patient survival was analyzed. IGF-2 staining was correlated with tumor progression, PCNA staining and patient survival. Our results suggest that IGF-2 plays an important role in tumor progression and that IGF-2 staining is useful as a prognostic factor in colorectal cancer patients.

Adult↗
PubMedDate not supplied

Insulin release from a bioartificial pancreas using a mesh reinforced polyvinyl alcohol hydrogel tube. An in vitro study.

Islet transplantation with a bioartificial pancreas is a potential alternative to whole pancreas transplantation. The authors constructed a bioartificial pancreas using mesh reinforced polyvinyl alcohol hydrogel tubes (MRPT), in an attempt to clarify the in vitro responsiveness to glucose of islets seeded in the MRPT. When the MRPT were perfused in a small chamber with buffer containing 3.3 mmol or 16.7 mmol glucose, insulin release from the MRPT began to increase at 9 +/- 3 min, reaching a plateau at approximately 40 min after the glucose concentration in the perfusate increased from 3.3 to 16.7 mmol. When MRPT seeded with islets were subjected to static incubation in buffer containing 3.3 mmol or 16.7 mmol glucose, insulin release from the MRPT remained elevated for 3 hr of high glucose stimulation, the amount of secreted insulin depending upon the number of islets seeded. Although pre incubation of semipermeable membranes in culture medium containing fetal bovine serum prior to seeding with islets has recently been reported to improve insulin release, the authors found that such pre treatment of the MRPT did not have a beneficial effect. Their in vitro findings in this study suggest that the bioartificial pancreas using MRPT could be a promising therapeutic approach to human diabetes mellitus.

Animals↗