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Biomedical subjects

S Kuramoto

Publications and source records attributed to S Kuramoto.

At least 19 recordsLinked to original sources
PubMed1997

Flat cancers do develop in the polyp-free large intestine.

PURPOSE AND BACKGROUND: Qualitative and quantitative analysis of many flat early cancers that have been discovered during the last decade led us to recognize that a flat route of cancer development de novo is as important a route as the polypoid one. We aim to prove through a longitudinal study that these flat early cancers indeed develop in flat mucosa and not in an adenomatous polyp. METHODS: From January 1, 1990, to July 31, 1994, 554 patients underwent at least two colonoscopies. These patients consisted of 364 males, and average age was 59 years. We searched for flat early cancers developing in polyp-free colorectal mucosa on or after a second colonoscopy. Polyp-free mucosa here means an intestinal segment proved to possess no adenomatous polyp during the preceding colonoscopies, irrespective of the presence of polyps elsewhere. RESULTS: Four flat early cancers were found developing in polyp-free colonic mucosa in four patients. Average age of the patients was 67 years. Locations of the cancers were the transverse (3) and descending colons (1). The shapes were all depressed, and average size of the lesions was 11 mm. Two lesions were endoscopically resected, and two by surgery. CONCLUSION: These four depressed cancers developing in polyp-free mucosa show that flat early colorectal cancers do arise de novo and not from an adenomatous polyp having collapsed on itself.

Adenocarcinoma↗
PubMed1996

First experimental sutureless laser anastomosis of the large bowel: long-term study.

UNLABELLED: Large bowel anastomoses were successfully performed without sutures on New Zealand white rabbits using 1,064 nm, 0.4-W power pulsating Nd:YAG laser to create tissue welding. PURPOSE: The aim of this study was to assess long-term results of our experimental data and summarize our experimental work on laser colon anastomosis. METHODS: This experimental study investigated long-term integrity, degree of narrowing, animal body weight change, visual findings, microscopic appearance, and collagen concentration of laser colon anastomoses, compared with those of conventional sutured anastomoses at thirty and ninety postoperative days. RESULTS: Two animals in the laser group died without leakage. Postsurgical course in all remaining rabbits studied was uneventful. Bursting pressures in the two groups were equivalent, but the laser group exhibited a consistent narrowing tendency. However, laser anastomoses demonstrated fewer and milder adhesions, and animals showed a better recovery of body weight. Histologically, laser anastomoses showed better layer-to-layer reconstitution without foreign body response and with less fibrosis. Difference in collagen (hydroxyproline) concentration did not reach statistical significance. CONCLUSION: The nature of tissue welding via laser remains undefined, but there is definitely a future for laser bowel anastomosis.

Anastomosis, Surgical↗
PubMed1996

Floating gallbladder associated with histologically distinct double cancers.

A case of unusually hypermobile floating gallbladder in a 79-year-old woman with histologically distinct double cancers of the gallbladder is described. The patient presented with an abdominal cystic mass, which was palpable with easy mobility from the right lower quadrant practically to the left upper quadrant. Exploratory laparotomy was performed and the cystic mass was found to be a floating gallbladder. The cystic duct was elongated and obstructed, and had a long mesentery. After the operation, latent double cancers of the gallbladder were discovered on histopathological examination. The obstruction of the cystic duct was due to chronic inflammation and had resulted in hydrops of the gallbladder. This was suspected to have played an important role in the carcinogenesis. We believe that this is the first report of a floating gallbladder associated with double gallbladder cancers.

Adenocarcinoma↗
PubMed1995

Etiology of gastric remnant cancer with special reference to the effects of denervation of the gastric mucosa.

BACKGROUND: Gastric mucosal blood flow, secretion of mucin, and renewal of the gastric mucosal cells are considered to be defensive factors against gastric mucosal injuries. These factors are regulated by the nervous system and neuropeptides. Gastrectomy may affect this regulation and induce gastric mucosal changes, such as atrophic gastritis and carcinoma. The effects of denervation of the gastric mucosa on tumorigenesis of the remnant stomach were investigated. METHODS: Using male Wistar rats, four groups of Billroth I (B-I)gastrectomy, Billroth II (B-II) gastrectomy, and those with denervation were conducted. Subdiaphragmatic truncal vagotomy was performed in the denervated group. Thirty weeks after the operations, histologic examination and periodic acid-Schiff--Alcian blue (PAS-AB) staining of the gastric mucosa, analysis of cell kinetics of the gastric mucosa by immunohistochemistry of proliferating cell nuclear antigen, and measurement of intragastric pH, intragastric bile acid concentration, and serum gastrin levels were performed. No carcinogenic agents were given. RESULTS: The B-I group showed no remarkable gastric mucosal changes, but B-I with denervation showed a significant increase in the development of tumor (67%) and carcinoma (42%). In the B-II groups, the denervation induced a significant increase in tumorigenesis, from 22% to 58%. Analysis of cell kinetics revealed a significant increase of labeling index in those groups that developed tumors. PAS-AB staining showed a decrease of PAS positive mucin but an increase of acidic mucin-producing cells in the denervated groups, suggesting an increase in the number of immature cells that are more susceptible to atrophic gastritis and carcinoma. There was no close relationship between tumorigenesis and intragastric pH, intragastric bile acid concentration, or serum gastrin levels. CONCLUSIONS: After gastrectomy, not only duodenogastric reflux, but also the denervation of the gastric mucosa play an important role in the etiology of gastric remnant cancer.

Animals↗
PubMed1995

How do colorectal cancers develop?

BACKGROUND: The aim of this study was to reveal (1) whether a flat adenoma is the precursor of a flat cancer and (2) the more frequent pathway in colorectal cancer development-a flat cancer or a polypoid cancer. METHODS: Clinical features and histologic characteristics of 97 flat early cancers, 138 polypoid early cancers, 60 advanced cancers involving the muscularis propria, and 185 flat adenomas were investigated. RESULTS: Of the flat cancers, 89.7% were not accompanied by residual adenoma and are considered to have arisen de novo. The distribution of flat adenomas and flat cancers was significantly different, and a follow-up of flat adenomas did not reveal any rapid growth or carcinomatous changes in the flat adenomas. The shape of advanced cancers involving only the muscularis propria almost matches that of flat early cancers. Fifty-two of 97 flat cancers and 19 of 138 polypoid cancers invaded the submucosal layer. CONCLUSIONS: Flat adenomas are not considered to be precursors of flat cancers. Advanced cancers of the large intestine originate mainly from flat cancers arising de novo. The percentage of the advanced cancers that originate from flat cancers is estimated to be 71.2% (52 of 52 +/- 19) at a minimum.

Adenoma↗
PubMed1994

Experimental laser anastomosis of the colon. Long-term results and histologic findings after laser closure of colotomies.

PURPOSE: Our previous experimental work showed the feasibility of colon anastomosis using laser; however, it also revealed a narrowing tendency after laser anastomosis. Long-term observation of the postoperative course of laser anastomosis was planned to assess this point. METHODS: Clinical observation and histologic examination of transverse colotomies (average, 21.2 mm) in New Zealand white rabbits (n = 12) closed with a 1,064-nm neodymiumyttrium aluminum garnet (Nd:YAG) laser were carried out up to the third postoperative month, compared with closure of colotomies using a single layer of interrupted sutures of 5-0 Maxon (Davis & Geck, Pearl River, NY) in a control group (n = 12). RESULTS: Whereas the narrowing tendency was observed up to one month after the operation in the laser group (P < 0.05), it disappeared at three months following the operation without causing abnormal weight loss during the experiment. Simultaneously, there was again a marked decrease in adhesion formation following laser anastomosis (P < 0.01). Collagen fibers were observed earlier in the laser group. CONCLUSIONS: An earlier commencement of collagen synthesis after laser anastomosis was proved. A narrowing tendency, which was observed from seven days to one month postoperatively, disappeared at three months after laser anastomosis without exerting any effect on growth.

Anastomosis, Surgical↗
PubMed1993

Completely thrombosed giant fusiform aneurysm in a young patient--case report.

A completely thrombosed giant fusiform aneurysm of the peripheral anterior cerebral artery occurred in a 16-year-old female, with a familial and personal history of vascular headache for 4 or 5 years. She was admitted in a drowsy state with severe headache. Computed tomography revealed subarachnoid hemorrhage and intracerebral hemorrhage as a mottled and ring-like high-density area in the left paramedian frontal lobe not enhanced postcontrast. Left carotid angiography demonstrated an avascular mass and a 5 cm defect in the A3 portion of the anterior cerebral artery. The rupture of the giant fusiform aneurysm was confirmed intraoperatively.

Adolescent↗
PubMed1993

[A case of Turcot syndrome (glioma polyposis)].

We reported a case of Turcot Syndrome (glioma polyposis) in a 19-year-old woman with nonfamilial polyposis coli and adenocarcinoma of the colon, and grade 3 astrocytoma in the right parietal lobe. The patient was admitted with the complaint of general convulsion after colostomy for polyposis and adenocarcinoma of the colon. CT scans on admission showed a large parietal tumor in the right side. Total removal was performed successfully and histological examination showed astrocytoma grade 3. One year after the operation, the tumor recurred. Conservative treatment failed to improve her condition and she died one year later. Turcot Syndrome (glioma polyposis) is very rare and only 10 cases have been reported in Japan. In this report, the clinical characteristics of this syndrome were discussed.

Adenocarcinoma↗
PubMed1992

Coexisting diffuse axonal injury (DAI) and outcome of severe head injury.

The importance of coexisting diffuse axonal injury (DAI) and outcome were studied in 107 patients with diffuse and focal brain injury. Comprehensive neuropathological study was undertaken in 26 fatal patients. There was a clear rank order of the mortality rate in the lesion type. The rank order of good recovery and moderate disability was also similar to the inverse of the mortality ranking. The pathological "marker" of DAI, macroscopic lesions in the corpus callosum and dorsolateral quadrant of the upper brainstem and histological evidence of axonal retraction balls, were commonly found not only in patients with diffuse brain injury but also in focal brain injury. The type of intracranial lesion in severe head injury is thus an important factor in determining outcomes and DAI of varying severity is the common subjacent lesion in the fatal patients.

Adolescent↗
PubMed1992

Monitoring of severe head-injured patients with transcranial Doppler (TCD) ultrasonography.

Intracranial haemodynamics were studied in 36 patients with severe head injury and experimental animals with acute intracranial hypertension by the use of TCD ultrasound. The mean flow velocity (FV) in the basal cerebral arteries commonly decreased on the side of the haematoma depending on intracranial pressure (ICP) elevation and cerebral perfusion pressure (CPP) reduction in focal brain injury. The FV decreased bilaterally and there was no difference between the right and left sides in diffuse brain injury without a clear relationship between the FV and CPP. The FV of the middle cerebral artery and blood flow in the internal carotid artery exhibited flow patterns which changed correlatively depending on CPP reduction in experimental animals. Monitoring with TCD ultrasound is valuable in evaluating compression ischaemia in focal brain injury. But many complicated factors are considerable in diffuse brain injury.

Adolescent↗
PubMed1992

First experimental sutureless end-to-end laser anastomosis of the large bowel. Short-term results.

Completely sutureless end-to-end large bowel anastomoses were successfully created in New Zealand white rabbits (n = 26) by using a low-energy (0.4-W wave of power) Nd:YAG laser to produce welded anastomoses. In this study, the short-term integrity, degree of narrowing, macroscopic appearance, and microscopic findings were compared with those of the conventional interrupted one-layer anastomosis (n = 24) at zero, one, four, and seven days after surgery. Two rabbits in the laser group died from leakage. All remaining animals had an uneventful postoperative course. The bursting pressures in the laser group at zero, one, and four days were lower than those in the control group. The narrowing index of the laser anastomosis was higher than that of the suture anastomosis at four and seven days. However, the laser anastomoses showed fewer adhesions, no instances of bowel obstruction, and histologic healing with less fibrosis. The technique of laser anastomosis presents a promising alternative to suturing in reconstitution of the large bowel.

Anastomosis, Surgical↗