Biomedical subjects

M Imamura

Publications and source records attributed to M Imamura.

At least 145 records · Page 8Linked to original sources

PubMed2000

Aortoesophageal fistula caused by foreign body.

Aortoesophageal fistula is rare. A woman who developed aortoesophageal fistula after swallowing a fish bone developed hematemesis. 7 days later, we resected a false aneurysm near the left subclavian artery and repaired this section twice. Despite these measures, the woman died on hospital day 21. The clinical diagnosis was massive hematemesis from an infected aortic wall. The method of diagnosis, control of infection, and operative repair of aortoesophageal fistula are discussed.

Aortic Diseases↗

PubMed2000

FDG-PET of autoimmune-related pancreatitis: preliminary results.

The purpose of this retrospective study was to elucidate the fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) findings in autoimmune-related pancreatitis (AIP), which is a reversible chronic pancreatitis with an autoimmune cause. The study group comprised six patients with clinically diagnosed AIP. After 370 MBq (10 mCi) of FDG had been injected intravenously, the abdomen and/or the whole body was scanned at 1 h post injection in all patients, and scanning was repeated at 2 h in four patients. PET findings were evaluated visually and/or semiquantitatively using the standardized uptake value (SUV). In four of the six patients, PET demonstrated intense uptake in the whole pancreas, which appeared swollen on computed tomography, and the accumulation increased with time in three patients. In one patient, intense focal uptake in the pancreatic head was observed, and the accumulation decreased over time. In the remaining patient, no abnormal accumulation in the pancreas was observed. Follow-up PET scanning after steroid therapy was performed in three patients, and intense FDG uptake was no longer observed. Our preliminary data show that AIP can cause intense FDG uptake in the pancreas. This fact, and the benign status of the condition, should be kept in mind when making a diagnosis with FDG-PET in patients with pancreatic disorders.

Cell Survival↗

PubMed2000

Curative resection of microgastrinomas based on the intraoperative secretin test.

The intravenous secretin injection test (secretin test) has been used for the differential diagnosis of gastrinoma. In this study we report that the intraoperative secretin test (IOS test) is also useful for determining the extent of curability in patients with Zollinger-Ellison syndrome (ZES). Twelve patients with ZES underwent surgical exploration and the IOS test. The results of the IOS test were obtained by rapid radioimmunoassay of the serum gastrin level (IRG) within 60 minutes. The test was diagnosed as negative when the maximum increase of serum IRG was less than 80 pg/ml and also less than 20% of the basal serum IRG level. Three of the twelve patients underwent pancreatoduodenectomy (PD), and two patients underwent distal pancreatectomy. Extirpation of duodenal tumors with dissection of regional lymph nodes was performed in seven patients. In two of the seven patients the IOS test remained positive after extirpation of the duodenal tumors and the dissection of regional lymph nodes. In one patient PD was performed on the basis of the positive results, and the IOS test became negative after PD. In the other patient, two tiny metastatic liver tumors were identified and were resected, but the IOS test did not become negative. We closed the abdomen in 11 patients when we obtained negative results from the IOS test. The results of the IOS test were almost identical to the data obtained by the standard assay postoperatively. The serum IRG levels of all but one patient fell to the normal level, and the secretin test became negative postoperatively. The IOS test is thus useful and indispensable for curative resection of microgastrinomas in patients with ZES.

Adult↗

PubMed2000

Fatal cerebral hemorrhage associated with cyclosporin-A/FK506-related encephalopathy after allogeneic bone marrow transplantation.

We report a case of cerebral hemorrhage associated with cyclosporin A (CsA)/FK506-related encephalopathy that developed in a 16-year-old woman after allogeneic bone marrow transplantation. Hematopoietic engraftment occurred on day 15, and the patient developed systemic convulsions after CsA was replaced by FK506 for the treatment of acute graft-versus-host disease (GVHD). Based on magnetic resonance imaging, laboratory findings and cerebrospinal fluid studies, she was diagnosed as having CsA/FK506-related encephalopathy with cerebral hemorrhagic infarction. Although she recovered completely after discontinuation of FK506, she developed convulsions again 15 days after re-administration of FK506. A computed tomography scan showed cerebral hemorrhage. She died of respiratory failure. Vascular damage induced by immunosuppressive drugs and enhanced by acute GVHD seemed to be the cause of the cerebral hemorrhage. Since hypertension, which was present during both of the central nervous system events, seemed to have contributed to the development of the cerebral hemorrhage, it is proposed that CsA and FK506 should be reduced or discontinued when patients who have risk factors of hypertension become hypertensive even if they have no symptoms of neurotoxicity.

Adolescent↗

PubMed2000

T-cell co-signalling molecules in graft-versus-host disease.

Allogeneic stem cell transplantation (allo SCT) is now frequently performed for the treatment of haematological malignancies and aplastic anaemia. However, graft-versus-host disease (GVHD) is still the major complication after allo SCT, producing immune deficiency, infection, organ damage and, occasionally, patient death. The antigen-specific signal mediated by the T-cell receptor (TCR) is essential for activation of T-cells; however, additional co-stimulatory signals are required for complete T-cell activation. Therefore, blocking strategies of co-stimulatory signals have been evaluated as targets of therapeutic intervention for GVHD after allo SCT. In a mouse bone-marrow transplantation (BMT) model, the administration of CTLA4-Ig, which blocks the interaction of CD28 on T-cells and B7 molecules on antigen-presenting cells (APCs), can prolong survival of allo BMT recipients, although this effect was not complete. In addition, the anti-CD40L (CD154) monoclonal antibody (mAb), which can interfere with the interaction of CD154 on T-cells and CD40 on APCs, can induce long-term graft survival in the murine model. Combined administration of CTLA4-Ig and anti-CD40L mAb can prevent allograft rejection in primates. Therefore, it seems the most powerful method to prevent the alloimmune response in vivo. The Fas/Fas ligand pathway is also involved in pathogenesis of GVHD. Anti-FasL mAb can reduce the mortality of GVHD and improve intestinal lesions. Recently, it was reported that donor bone marrow treated ex vivo using CTLA4-Ig reconstituted haematopoiesis in vivo with a relatively low risk of GVHD in human allo BMT. Therefore, selective blocking strategies for T-cell co-signalling might be useful for the prevention of GVHD in human allo SCT.

Animals↗

PubMed2000

Physiological role of sinusoidal endothelial cells and Kupffer cells and their implication in the pathogenesis of liver injury.

We reviewed the morphological characteristics and physiological functions of hepatic sinusoidal endothelial cells (SECs) and Kupffer cells (KCs), both of which are major components of the hepatic sinusoid, and we showed the implication of these hepatic sinusoidal lining cells in the pathophysiology of the liver, based on our experimental studies. The most outstanding feature of SECs is that they are provided with numerous fenestrae, thereby allowing direct communication between the sinusoidal lumen and the space of Disse. Physiologically, SECs play a role in filtration function, endocytic function, and putative participation in the regulation of sinusoidal blood flow. As for KCs, they account for major portion of fixed macrophages in the entire body, and exhibit vigorous activity for phagocytosis, and produce many kinds of soluble mediators such as cytokines, prostanoids, oxygen radicals, and proteases. To determine whether these cells are implicated in pathophysiological processes in the liver we directed our attention to liver injury associated with sepsis and cold-preservation injury of liver tissue. In a septic rat model, we found that when KCs that included hepatic macrophages were activated, they released excess tissue-toxic mediators, probably leading to SEC damage. In the cold-preserved liver,we demonstrated that KCs were functionally activated and that the morphology of SECs was destroyed. When the liver was reperfused with plasma and a leucocyte suspension, hypercoagulability and increased leucocyte adherence occurred. In both experimental models, we demonstrated that KC blockade ameliorated the liver injury, and this was associated with the morphological improvement of SECs. Thus, we showed the pathogenetic implication of KCs and SECs, due possibly to microcirculatory disturbance in the hepatic sinusoid, and further emphasized the involvement of activated KCs in SEC impairment.

Animals↗

PubMed2000

Adeno-endocrine cell carcinoma of the gallbladder.

We encountered a rare case of adeno-endocrine cell carcinoma of the gallbladder in an 81-year-old woman. Imaging study revealed a common bile duct stone. Endoscopic sphincterotomy was performed, and the stone was extracted successfully. Thereafter, cholecystectomy was performed. A papillary tumor was found in the neck of the gallbladder. Histologically, the tumor consisted of two components, well differentiated adenocarcinoma and endocrine cell carcinoma. However, no clinical signs of tumor hormonal activity were observed. The tumor cells in the area of the endocrine cell carcinoma were small and round. Histochemical studies of these tumor cells were positive for chromogranin A and Grimelius silver impregnation. The tumor cells in the area of the adenocarcinoma were well differentiated adenocarcinoma and included goblet-type cells with a tubular structure or solid growth pattern. These adenocarcinoma cells stained positively for Alcian blue and periodic acid-Schiff, and both types of tumor cells stained positively for carbohydrate antigen and carcinoembryonic antigen. It was suggested that the histogenesis of the endocrine cell carcinoma of the gallbladder was closely related to that of the adenocarcinoma.

Adenocarcinoma↗

PubMed2000

Effects of Helicobacter pylori infection on Zollinger-Ellison syndrome.

Both Zollinger-Ellison syndrome (ZES) and Helicobacter pylori infection are major etiologic factors for peptic ulcer. The aim of this study was to investigate the effect of H. pylori infection on ZES with special reference to acid secretion. Sixteen patients with ZES were selected (median age, 59 years; range, 39-66 years; M/F, 9/7), and H. pylori status, ulcer location, gastric acid secretion, serum pepsinogen (PG) I and II concentrations, and PG I/II ratio were determined. The seroprevalence of H. pylori infection was 50%, whereas active H. pylori infection was seen in only 25% of the patients. Thirteen patients had duodenal ulcer (DU), 1 had gastric ulcer (GU), and 2 had both GU and DU. DU was seen in both H. pylori-positive and H. pylori-negative patients, whereas GU was found only in H. pylori-positive patients. Both basal and maximal acid outputs were significantly lower in H. pylori-positive patients than in H. pylori-negative patients (P< 0.05). Moreover, both serum PG I and the PG I/II ratio were significantly lower in H. pylori-positive patients than in H. pylori-negative patients. These results indicate that ZES is an independent risk factor for DU, but H. pylori infection may play some role in the development of GU in ZES. In patients with ZES, H. pylori infection may reduce both hypersecretion from parietal cells and PG I secretion from chief cells, and hyperacidity of the stomach in ZES may have eradicated H. pylori in some patients.

Adult↗

PubMed2000

Pancreatic lesions in von Hippel-Lindau syndrome: the coexistence of metastatic tumors from renal cell carcinoma and multiple cysts.

Multiple cysts and benign cystadenomas of the pancreas have been documented occasionally in von Hippel-Lindau syndrome (HLS); however, the malignant involvement of the pancreas in HLS is very rare. We report a case of HLS in which metastatic tumors from renal cell carcinoma (RCC) coexisted with multiple cysts in the pancreas. A 22-year-old woman with a history of HLS had undergone a partial resection of the left kidney for RCC 3 years earlier, at which time a solid mass in the pancreatic tail and multiple pancreatic cysts were also incidentally detected by computed tomography. Over the following 3 years, the mass enlarged slightly, thus raising suspicions that it might be a primary neoplasm of the pancreas. She was referred to the Department of Surgery and Surgical Basic Science to undergo surgery. In addition to the tumor in the pancreatic tail, however, further tumors in the pancreatic head were also disclosed by preoperative celiac arteriography and intraoperative palpation and ultrasonography. A distal pancreatectomy was performed, because the enucleation of all the tumors in the pancreatic head was technically impossible and because the patient declined a total pancreatectomy. A histologic examination of the mass in the pancreatic tail revealed metastatic RCC. This case emphasizes that metastatic disease should be included in the differential diagnosis when evaluating the pancreas in a patient with HLS.

Adult↗

PubMed2000

Results of the double switch operation in the current era.

BACKGROUND: In patients with atrioventricular and arterioventricular discordance congenitally corrected transposition, the morphologically right ventricle may progressively deteriorate while functioning in the systemic circuit. The double switch operation has been proposed to limit this functional deterioration. METHODS: From October 1993 to August 1998, the records of 27 patients with congenitally corrected transposition were reviewed. Age at operation ranged from 3 months to 55 years. Associated defects included ventricular septal defects in 18, pulmonary atresia in 7, and pulmonary stenosis in 11 patients. Twenty-two patients had double switch operations (10 arterial switch plus Senning procedures and 12 Rastelli plus Senning procedures). Five patients were not candidates for the double switch. Before the double switch, 6 patients required pulmonary artery banding and 10 had functioning systemic to pulmonary artery or cavopulmonary shunts. RESULTS: There was no early or late mortality. Two patients required pacemaker implantation, both later regained normal sinus rhythm. Tricuspid valve function improved in all patients except one. Moderate left ventricular dysfunction developed 5 months postoperatively in 1 patient. CONCLUSIONS: The double switch operation can be performed in selected patients with minimal early morbidity and mortality. Longer follow-up is necessary to determine whether this complex approach is indeed warranted.

Adolescent↗

PubMed2000

Aortic valve repair after arterial switch operation.

A patient with transposition of the great arteries and a ventricular septal defect underwent an arterial switch operation 15 months after pulmonary artery banding. At 12 years of age, severe neoaortic valve regurgitation, due to dilated aortic sinuses and poor leaflet coaptation, developed. Aortic valve repair involved placement of subcommissural sutures, elliptical excision and tailored reduction of two anterior aortic sinuses, with triangular patch expansion of the proximal ascending aorta. A good result was obtained.

Aortic Valve↗

PubMed2000