Biomedical subjects

T Wakahara

Publications and source records attributed to T Wakahara.

At least 19 recordsLinked to original sources

PubMed2006

[Surgical resection for sternal metastasis from gastric cancer; report of a case].

A 72-year-old woman underwent a distal gastrectomy for gastric cancer 8 years ago. Histopathological examination showed poor differentiated adenocarcinoma. She had no symptom but chest computed tomography (CT) revealed tumor at sternum. A percutaneous needle biopsy under CT was performed and showed poor differentiated adenocarcinoma. Therefore, extirpation was performed. The tumor was located in sternum and left 2nd rib and thought to invade greater pectoral muscle and left lung. The tumor was resected at sufficient margin with surrounding tissues. Compared with tissue of gastric cancer for histopathological examination, sternal tumor had homeomorphous formation and was diagnosed sternal metastasis from gastric cancer. Sternal metastasis from gastric cancer is a rare disease and standard therapy is controversial. In this case, no findings of reccurrence have been found for 8 months after the operation.

Adenocarcinoma↗

PubMed2001

XAFS study on metal endohedral fullerenes.

Structure of metal endohedral fullerenes is studied by XAFS and XANES. The Sc-Sc distance of 2.23(1) A determined from Sc K-edge XAFS supports the formation of a triangular Sc3 cluster in Sc3@C82 as is found by MEM analysis for the X-ray diffraction. Gd L(III)-edge XAFS of Gd@C82 shows that the first and the second neigboring Gd-C distances are 2.51(2) and 2.85(4) A, respectively. The La-La distance of La2@C80 has been determined to be 3.90(1) A at 40 K. This value does not change when increasing temperature [3.90(2) A at 240 K]. The position and the valenece of the Eu atom in Eu@C60 are also discussed based on Eu L(III)-edge XAFS and XANES.

Journal Article↗

PubMed2000

A first photochemical bis-germylation of C60 with digermirane

[reaction: see text]In the photochemical bis-germylation of C60 with 1,1,2,2-tetrakis(2,6-diethylphenyl)-1,2-digermirane (1), a cycloadduct (2) is obtained in high yield for the first time. Spectroscopic analysis and theoretical investigation confirm that 2 (which has C1 symmetry) results from 1,4-cycloaddition. Control experiments and laser flash photolysis experiments suggest that an exciplex intermediate is responsible for the formation of 2. The redox properties of 2 were examined by differential pulse voltammetry.

Journal Article↗

PubMed2000

Inflammatory pseudotumor of the liver with primary sclerosing cholangitis.

Inflammatory pseudotumor (IPT) of the liver is a rare benign variant of hepatic masses, and its exact etiology has not been elucidated. We report a case of IPT associated with primary sclerosing cholangitis (PSC). The patient was a 50-year-old man admitted to our hospital because of jaundice. Abdominal ultrasonography (US) and computed tomography showed multiple dilations of the intrahepatic bile ducts and multiple masses in the liver. On magnetic resonance imaging, the masses were slightly hypointense on T1-weighted images and slightly hyperintense on T2-weighted images. On T1-weighted images after the bolus infusion of Gd chelate, the masses had no contrast enhancement, and they were hypointense in the arterial phase and portal venous phase. However, they were slightly enhanced and became almost isointense relative to the surrounding normal liver parenchyma in the delayed phase. Endoscopic retrograde cholangiography demonstrated multiple irregular strictures and dilations of the intrahepatic bile ducts. Angiography demonstrated no abnormal findings, but, interestingly, subsequent dynamic CO2-enhanced US showed a strongly hyperechoic string, indicating that an artery had penetrated through the hypoechoic mass. A US-guided percutaneous needle biopsy revealed that the lesions were morphologically comparable to IPT. After cholangiography and microscopic analysis of the tumor, the final diagnosis was determined to be IPT of the liver with PSC. A number of previous reports have suggested a possible relationship between IPT and PSC, based on pathological findings. This report confirmed, based on clinical findings, that PSC is one of the causes of hepatic IPT.

Bile Ducts, Intrahepatic↗

PubMed1999

In vitro migratory potential of rat quiescent hepatic stellate cells and its augmentation by cell activation.

In liver injury, hepatic stellate cells are considered to depart from the sinusoidal wall and accumulate in the necrotic lesion through migration and proliferation. In this study, we investigated the migratory capacity of quiescent stellate cells in vitro and analyzed the relationship with proliferative response. Freshly isolated stellate cells that were seeded in the upper chamber of Cell Culture Insert (Becton Dickenson, Franklin Lakes, NJ) started to migrate to the lower chamber at 1 day and increased in migration index to 19% at 2 days. Cells in the lower chamber were stretched in shape with many lipid droplets and showed quiescent properties, i.e., negative expression of alpha-smooth muscle actin (alpha-SMA) or platelet-derived growth factor receptor-beta (PDGFR-beta). Migratory capacity in quiescent cells was also shown in the Matrigel-coated insert. Matrix metalloproteinase-2 (MMP-2) messenger RNA expression was low just after isolation, but was enhanced as migration became prominent. Migrating cells further showed higher proliferative activity than resting ones. The presence of PDGF/BB and Kupffer cells accelerated stellate cell migration by the chemotactic mechanism and concurrently augmented proliferation, whereas that of dexamethasone and interferon-gamma (IFN-gamma) attenuated migration as a result of general suppression effects. Compared with quiescent ones, alpha-SMA and PDGFR-beta-positive activated stellate cells obtained by 14-day culture exhibited more rapid and prominent migration, being regulated by mediators in a similar manner as described previously. These data indicate that quiescent stellate cells undergo migration, which is linked to proliferation and enhanced by PDGF/BB and Kupffer cells, suggesting the involvement of this function in the initial phase of development of postnecrotic fibrosis.

Actins↗

PubMed1998

Endoscopic papillary balloon dilatation for common bile duct stones: efficacy of combination with extracorporeal shockwave lithotripsy for large stones.

BACKGROUND: Endoscopic papillary balloon dilatation (EPBD) is generally considered a safe and effective technique for removal of common bile duct (CBD) stones. However, some reports have prompted concern about the risk of pancreatitis following the procedure, and it seems to be more difficult and to require adjunctive procedures more frequently in patients with large stones. AIMS: To analyse the factors influencing pancreatitis after the procedure, and to examine which is the more suitable adjunct for treating large stones, mechanical lithotripsy (ML) or extracorporeal shockwave lithotripsy (ESWL). PATIENTS AND METHODS: EPBD was performed in 92 patients, including 40 with large stones (> or = 12 mm). These 40 patients were randomly assigned to two groups receiving ML or ESWL to fragment stones (20 patients each). RESULTS: Complete ductal clearance was obtained in all 92 patients. Significant elevation of the serum amylase level compared with the prior value (> 300 IU/l) was observed in 26 (28%), and eight (8.7%) developed clinical pancreatitis. To assess the influence of various factors on the amylase level, multivariate analysis was used. The number of stones and the time required for treatment had a significant influence on the incidence of increased amylase level (P < 0.05), and ML also significantly increased it (P < 0.05). On the other hand, the amylase level remained low in the ESWL group. ML caused elevation of amylase level in 11 patients (55%), while three (15%) had elevation after ESWL. CONCLUSIONS: In patients with multiple stones, elevation of the amylase level is more frequent. This seems to be because repeated cannulation and much time is required for treatment. In patients with large stones, the rate was also high if ML was used, but was low when ESWL was used. ESWL may reduce the incidence of pancreatitis.

Aged↗

PubMed1997

Usefulness of novel imaging modalities in diagnosis of focal nodular hyperplasia of the liver.

A 17-year-old woman was admitted because of a liver tumor found incidentally by ultrasonography. Liver function was normal and there were no markers of hepatitis viruses or malignancy. Abdominal ultrasonography, computed tomography (CT), and magnetic resonance imaging revealed a mass (2 cm in diameter) in the lateral segment of the left lobe of the liver. The lesion was not detected by hepatic arteriography. However, dynamic CT with fast scanning and dynamic CO2-enhanced ultrasonography demonstrated initial central enhancement of the mass followed by centrifugal spread of enhancement to the periphery. Color Doppler flow imaging detected a central color spot, shown to be an artery by a pulsed Doppler spectrum analysis. Fine-needle biopsy confirmed a diagnosis of focal nodular hyperplasia. Dynamic CT with fast scanning, dynamic CO2-enhanced ultrasonography, and color Doppler flow imaging were useful in detecting the vascular pattern specific to focal nodular hyperplasia. Investigation of further cases with these novel imaging modalities should help to establish a comprehensive diagnostic procedure and thus avoid unnecessary surgery for focal nodular hyperplasia, which is a completely benign lesion.

Adolescent↗

PubMed1988

[A case of early gastric cancer accompanied by Recklinghausen's disease].

In September, 1980, a 57-year-old male, was admitted to hospital for precise examinations to determine if he had Recklinghausen's disease, pneumoconiosis, and a duodenal ulcer. Endoscopy revealed a redness and a shallow depression of the posterior wall of the antrum, and a biopsy of a specimen led to the diagnosis of early gastric cancer, Stage II c. After the examination, the patient did not return to our department again. In May, 1987, however, the man was readmitted to our hospital, suffering from pains in the right back. X-ray and endoscopic findings revealed a gastric cancer with a center depression and a peripheral elevation (II a + II c). Histological findings showed the gastric cancer to be a moderately differentiated tubular adenocarcinoma, with a submucosal invasion that was also seen. This case, uncovered 80 months earlier, represents a rare instance in which an early gastric cancer, accompanied by Recklinghausen's disease, expanded slowly.

Adenocarcinoma↗

PubMed1988

[Primary ileal carcinoma].

Recently encountered is a case of a primary ileal carcinoma in which radical resection was performed. The history follows. A 76-year-old male was admitted to Miyako Hospital on January 12, 1986 complaining of abdominal pain of ten days duration. Pre-operative treatment extended over an eleven-day period without any symptomatic remission. A barium enema and roentgenographic examination that followed a barium ingestion revealed no abnormality in the large bowel, but a mechanical obstruction, typical of a carcinoma, was detected in the small intestine. On January 23, 1986, under a general anesthesia, the abdomen was opened through a midline rectus incision. A tumor was found in the terminal ileum 14 cm proximal to the ileocecal valve, and was causing almost total obstruction of the intestine. This tumor, with involved ileal and regional lymph-nodes, was resected, followed by an end-to-end anastomosis. The tumor, grossly circumscribed, was roughly circular in outline and protruded from the ileal wall. No lymph-node metastasis was found in histological sections. The diagnosis was a primary adenocarcinoma of the ileum. Few reports have been reported in Japan on radically resected primary carcinomas of the ileum. The future course of this case deserves careful study.

Adenocarcinoma↗

PubMed1987

[Ultrastructures of smooth muscles of the choledochus at the choledocho-duodenal junction].

The inner circular muscle (ICM) of the cat duodenum at the choledocho-duodenal junction is thickened, surrounding the choledochus at its proximal portion within the duodenal wall. Such a thickened portion of ICM is considered to be a main part which serves as a sphincter of the choledochus. This portion of the ICM was referred to as 'sphincter of choledochus' in the present study. The sphincter of choledochus and the adjacent ICM were studied by freeze-fracture and conventional thin sectioning methods by electron microscopy in order to clarify the morphological characteristics of smooth muscle cells in the sphincter of choledochus in comparison with ICM. Smooth muscle cells of the sphincter of choledochus were smaller (3-5 microns in diameter) in size, and had less developed dense patches and dense bands. However, they were richly innervated and had numerous gap junctions for electric coupling between cells. These findings indicate that sphincter of choledochus, though its contraction ability may be weaker than the ICM, can exhibit a highly synchronized contraction needed for the sphincter function.

Animals↗

PubMed1987

[Synchronous early double cancers of the stomach and gallbladder].

Presented is a case of a 76-year-old male who had a double cancer, in the stomach and the gall bladder. The gastric tumor was found to be a IIc early cancer that showed invasion into the submucosa, and was, histologically, tubular adenocarcinoma. The carcinoma of the gall bladder was limited to the mucosal layer, and was, histologically a papillary adenocarcinoma. Partial gastrectomy and cholecystectomy were performed. In a review of the literature in Japan, synchronous double cancer, an early gastric cancer and an early carcinoma of the gall bladder, is very rare and 3 only cases have been summarized, including this case.

Adenocarcinoma↗

PubMed1986

[Ultrastructural study of the ureter smooth muscle of the cat].

Morphological specializations of smooth muscles from the middle part of the cat ureter have been examined by electron microscopy using thin sections and freeze-fracture replicas. It is notable that there were many gap junctions which were characteristic in being formed on the surface of blunt cytoplasmic projections protruded from each neighboring cells. In addition to gap junctions, there were two other different junctions, i.e, intermediate junctions and "focal attachments". The latter represents the cell attachment in which two apposing plasma membranes are attached to each other without the intervension of basal lamina in the narrow intercellular space. Caveolae were lined in rows which were intervened by dense band zones parallel to the long axis of the muscle fibre as seen by freeze-fracture replica. Gap junctions were noted to be localized within or along the caveolar zones, being elliptical in shape with the long axis parallel to muscle fibres. As observed in thin sections, gap junctions in freeze-fracture replicas were noted on the top of cytoplasmic protrusions. No membrane specializations were observed in freeze-fracture replicas which corresponded to the "focal attachment" or intermediate junction as seen in thin sections. As to the innervation, the autonomic nerve terminals were in abundance, closely apposed to the smooth muscles. In addition to autonomic nerve terminals, sensory nerve terminals were observed between muscle fibres, consisting of axon terminals and lamellar cells, the same structure as mechanoreceptive lamellar corpuscles known in other organs.

Animals↗

PubMed1986

[A study of cases of early gastric cancer with hematemesis and/or melena].

In this hospital, gastric cancers showed a slightly lower incidence (9.3%) of hematemesis and/or melena than gastric ulcers (13.9%), and no distinct difference in such incidence between early gastric cancers and advanced gastric cancers was observed. A study of the literature on early gastric cancers presenting such symptoms revealed that male patients showed an extremely high incidence of these symptoms, as did those with depressed lesions, including types II c + III, and lesions occurring in the MC-C regions dominated by the left gastric artery.

Adult↗

PubMed1984