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Biomedical subjects

A Yamataka

Publications and source records attributed to A Yamataka.

86 records · Page 5Linked to original sources
PubMed1993

Distribution of neuromuscular junctions in the bowel affected by hypoganglionosis.

Using monoclonal antibody 171B5 against synaptic vesicle proteins, neuromuscular junctions and synapses in the muscle layers of the bowel affected by hypoganglionosis were labeled and their distribution analysed. In the hypoganglionic bowel, there were less synapses in the myenteric plexus and few neuromuscular junctions compared to normal bowels. The bowel dysmotility of the patient with hypoganglionosis appears to be due to inadequate innervation between ganglion cells and smooth muscle cells.

Colon↗
PubMed1993

A new technique for early detection of portal vein and arterial thromboses. Indwelling mesenteric venous catheterization and relevance to small bowel transplantation.

The aim of this study was to ascertain whether, in an animal model, continuous monitoring of mesenteric venous pressure (MVP) via an indwelling mesenteric venous catheter could assist in early detection of thrombosis of the portal vein (PVT) and superior mesenteric artery (SMAT). The role of portography via the catheter was also studied in confirming these complications. An animal model of PVT and SMAT was developed in pigs. At laparotomy, a 20-cm jejunal loop was isolated and a heparin-coated catheter was inserted into a mesenteric vein of the isolated jejunum and connected to a pressure transducer. Conditions of PVT were simulated by progressive occlusion of the portal vein (PV) using a silastic tourniquet and those of SMAT by superior mesenteric artery (SMA) clamping. MVPs (mm Hg) were found to significantly increase with all degrees of PV occlusion (P < 0.01, Student's t test) and to significantly decrease after SMA occlusion (P < 0.01). Portography clearly demonstrated all degrees of PV stenosis after PV occlusion and stasis of contrast medium during SMA occlusion. The authors feel that this method enables rapid diagnosis of PVT and SMAT and may be useful in the monitoring of the therapy for these complications after small bowel transplantation.

Animals↗
PubMed1993

Prolongation of rat cardiac allograft survival by a monoclonal antibody: anti-rat intercellular adhesion molecule-1.

A mouse monoclonal antibody 1A29, which binds to the rat intercellular adhesion molecule-1 (ICAM-1), was studied for its effect on cardiac allograft survival. Expression of ICAM-1 was detectable only on vascular endothelium in normal heart, but was induced on myocardium associated with interstitial mononuclear cell infiltration during acute rejection. Treatment with monoclonal antibody 1A29 for 10 days after transplantation in 15 rats significantly prolonged allograft survival (mean(s.d.) 18(2) days; P < 0.001), as compared with 15 isotype-matched control monoclonal antibody (mean(s.d.) 10(1) days) recipients. Five-day treatment with monoclonal antibody 1A29, when started at 5 days after transplantation (the time for which acute rejection is ongoing), also significantly extended the survival (mean(s.d.) 12(1) days; P < 0.01) in seven rats. On histological examination, treatment with monoclonal antibody 1A29 reduced the degree of T-cell infiltration of both CD4+ and CD8+ subsets, and greatly reduced myocardial necrosis, vascular injury and intravenous thrombi. These results indicate that an anti-ICAM-1 monoclonal antibody can be used to prevent or treat acute rejection in the rat cardiac allograft model and suggest that human ICAM-1 is an important target for immunosuppression in clinical organ transplantation.

Animals↗
PubMed1992

Hirschsprung's disease: diagnosis using monoclonal antibody 171B5.

A new reliable immunohistochemical method for diagnosing Hirschsprung's disease (HD) using our unique monoclonal antibody (MAb) 171B5 against synaptic vesicles is described. Fresh frozen sections of rectal tissues were used from 13 patients with HD aged 2 weeks to 13 months; 9 had rectosigmoid HD and 4 had total colonic aganglionosis (TCA). Comparable normal colonic and rectal specimens were also obtained from 13 age-matched controls. All specimens were labeled with MAb 171B5, to demonstrate neuronal innervation patterns of both mucosa and submucosa. In all control specimens, many synapses arranged in variciform plexuses were seen in the lamina propria, a moderate number in the muscularis mucosae, and dense clusters in the submucosal plexus. In all aganglionic specimens, only scanty numbers of synapses which were not organized in variciform plexuses were seen in the lamina propria, none in the muscularis mucosae, and a few in the submucosa. These findings suggest that MAb 171B5 immunohistochemistry on the lamina propria alone can differentiate between normal and aganglionic bowel and appears to be a reliable and useful method for detecting HD on suction rectal biopsy.

Antibodies, Monoclonal↗
PubMed1992

Patchy distribution of rejection changes in small intestinal transplantation.

The aim of this study is to determine the distribution of histological changes of rejection in small intestinal transplantation. Thirty-nine rats were randomized into two groups: group I (n = 15), syngeneic transplants and group II (n = 24), allogeneic transplants. Grafts were excised and examined on days 2, 4, and 8 after transplantation. All grafts of the syngeneic group showed normal mucosa by day 4. However, by this time, all grafts of the allogeneic group demonstrated rejection changes with a patchy distribution in the mucosa. Therefore, with a biopsy from the stoma site there is a risk of missing early rejection.

Animals↗
PubMed1992

Correlation between extrinsic nerve fibers and synapses in the muscle layers of bowels affected by Hirschsprung's disease.

The aim of this study is to clarify any correlation between nerve terminals (synapses) and proliferating extrinsic nerve fibers in the muscle layers of bowels affected by Hirschsprung's disease (HD). Synapses and extrinsic nerve fibers in the muscle layers of bowels of 10 patients with HD and 8 comparable controls were labeled with monoclonal antibody (MAb) 171B5 and acetylcholinesterase (AChE), respectively. In the control a rich and even distribution of synapses, representing neuromuscular junctions, was seen in the muscle layers, together with dense clusters of synapses in the adjacent myenteric plexuses; proliferation of extrinsic nerve fibers was not seen. In the transitional oligoganglionic segment of HD, many synapses were present in the myenteric plexus, but a few synapses in the muscle layers; there was a gradual increase of extrinsic nerve fibers from proximal to distal. In the narrow aganglionic segment very few synapses were seen in the muscle layers; proliferating nerve fibers and bundles were prominent. We conclude that the muscle layers of bowels affected by HD were almost denervated despite presence of intrinsic nervous elements in the oligoganglionic segment and proliferating extrinsic nerve fibers in the aganglionic segment.

Hirschsprung Disease↗
PubMed1991

Magnetic resonance imaging for localizing the nonpalpable undescended testis.

A prospective evaluation of the value of magnetic resonance imaging (MRI) for localizing the nonpalpable undescended testis was performed in 17 boys aged 1 year to 5 years 4 months who had a clinical diagnosis of nonpalpable testes. The results were compared between the MRI, ultrasonographic, clinical, and definitive surgical diagnosis in all patients. Nine nonpalpable undescended testes were identified in the inguinal canal or just proximal to the inguinal ring by MRI, and these were confirmed by surgical findings. Six nonpalpable testes were not observed by MRI, and the absence of these testes was surgically confirmed. Like scrotal testes, all the undescended testes showed a low intensity on sequences with a short repetition time (TR) and echo time (TE), and a high intensity on long TR/TE sequences. Undescended testes were observed better on coronal images than on axial images. MRI promises to become an important diagnostic tool in the detection of nonpalpable undescended testes.

Child, Preschool↗
PubMed1989

Treatment of laryngotracheoesophageal cleft.

Four patients with laryngotracheoesophageal cleft were treated in our institution. Two of the patients survived and two died. Cleft levels ranged from partial 15 mm laryngotracheoesophageal to total with extended right bronchoesophageal cleft.

Bronchi↗
PubMed1989

[Current state of the treatment of congenital biliary atresia].

Current state of the treatment of biliary atresia was studied concerning following factors based on our experience of 240 patients during 1966 to 1988, particularly 103 patients who received Kasai operation with Suruga II modification. 1. Operative results: Overall and Suruga II. 2. Predictable factors of the prognosis at the first radical operation, especially, among the age, the hepatic fibrosis and the size of ductuli at porta hepatis. 3. Technical refinement of Kasai operation, especially concerning the exposure of portal area and the anastomosis. 4. Our recent device of modified Kasai operation, that is, hepatic portoduodenostomy with interposition of ileocecoappendix. 5. Rehepatic portoenterostomy in case of poor postoperative bile flow. From our experiences, Kasai operation is indicated to the patients who have mild or moderate liver fibrosis and good sized ductuli at porta hepatis, but not to the patients who have advanced liver fibrosis and extremely poor ductuli. In such circumstance, liver transplantation should be considered. Rehepatic portoenterostomy is only indicated to the patients who have a good bile flow after the initial Kasai operation but not to the patients who have no bile flow.

Biliary Atresia↗
PubMedDate not supplied

A case with duodenal duplication cyst: prenatal diagnosis and surgical management.

OBJECTIVE: We report the first case of a subhepatic cystic mass diagnosed in utero that subsequently proved to be a duodenal duplication cyst. METHOD: Conventional prenatal abdominal ultrasound. RESULTS: On prenatal ultrasonography, the differential diagnosis was choledochal cyst, bowel duplication cyst, or omental cyst. CONCLUSION: The prenatal detection of a cystic mass allowed close neonatal surveillance and timely surgical intervention prior to the onset of potentially serious complications.

Adult↗
PubMedDate not supplied

Hemodynamic changes in blood flow through the denervated liver in pigs.

We investigated the effects of liver denervation on hemodynamic circulation in seven anesthetized pigs. Simultaneous measurements of the hepatic artery and portal vein were performed with an ultrasound Doppler flow meter before and after liver denervation. Neither resting systemic nor hepatic hemodynamics changed following liver denervation. However, temporary occlusion of the portal vein resulted in a significant increase in hepatic artery flow in the innervated liver (from 123 +/- 15 ml/min to 177 +/- 17 ml/min, p < .01), whereas, in the denervated liver, a significant decrease was observed (from 128 +/- 11 ml/min to 106 +/- 19 ml/min, p < .05). Thus, the reciprocity between the hepatic artery and portal vein in the hepatic artery flow during portal vein occlusion might intensify symptoms of portal vein thrombosis in liver transplantation. In the denervated liver, a significant decrease also occurred in systolic blood pressure and central venous pressure from 1 to 3 min after portal vein occlusion. Since the liver plays a crucial role in the maintenance of cardiovascular homeostasis during blood loss, it is likely that denervation at the porta hepatis induced a lack of vasoconstriction in the portal territory. Liver denervation might further exacerbate this response to hypotension. The current study confirms that the hepatic nerves play an important role in hepatic arterial and portal venous interactions aimed at maintaining a constant blood flow through the liver. We also suggest that the hepatic nerves are important for cardiovascular homeostasis.

Animals↗