PubMed Health⌕ Search

Biomedical subjects

K Shibuta

Publications and source records attributed to K Shibuta.

34 records · Page 2Linked to original sources
PubMed1995

Microsatellite instability in multiple gastric cancers.

To better elucidate the role of genetic instability in the development of gastric cancer, microsatellite alterations were examined in a total of 30 gastric cancers that developed in 14 Japanese patients with multiple gastric cancers, which are considered to have possibly occurred under the same genetic background and in the same microenvironment of the stomach. Microsatellite instability (MSI) in multiple gastric cancers was recognized in 11 out of 14 cases (78.5%) and in 16 out of 30 cancers (53.3%). Eight out of 11 cases showing MSI exhibited a heterogeneity of microsatellite alterations. The incidence of microsatellite instability in the multiple gastric cancers cases was significantly higher than that in the solitary gastric cancer cases reported previously (20.8%: 5 out of 24 cases). These results suggested that (1) genetic instability plays a more important role in the development of multiple gastric cancers than in that of solitary gastric cancer and (2) the heterogeneity of MSI in multiple gastric cancers may not be a rare event, although the significance of the heterogeneity could not be clarified.

Adenoma↗
PubMed1995

Microsatellite instability in Japanese esophageal carcinoma.

Recent studies have shown that microsatellite instability (MSI) may play an important role in the development of various types of cancer. However, there have been only 2 reports describing MSI in esophageal carcinoma and the clinicopathologic significance of MSI in this malignancy has not yet been clarified. To better elucidate the role of genetic instability in the development of esophageal carcinoma, we investigated the presence of MSI in 32 cases of esophageal cancer using paired samples of fresh frozen tumor and normal tissue by a method based on the polymerase chain reaction. MSI was defined as occurring in tumors which showed altered banding patterns at one or more microsatellite loci. The incidence of MSI in esophageal carcinoma was 6 out of 32 patients. MSI was observed more frequently in cases with small-cell carcinoma (2 out of 2) than in cases with squamous-cell carcinoma (4 out of 29). No cases with adenocarcinoma or Barrett's metaplasia were included in our series. No significant correlations between MSI and other clinicopathologic parameters were observed. The present study suggests that (1) some Japanese esophageal carcinomas certainly correlate with DNA replication error, and (2) MSI may be more frequent in small-cell carcinoma of the esophagus than in squamous-cell carcinoma of the esophagus.

Aged↗
PubMed1995

The expression of tumor-rejection antigen "MAGE" genes in human gastric carcinoma.

BACKGROUND & AIMS: The genes MAGE-1 and MAGE-3 both encode melanoma peptide antigens recognized by major histocompatibility complex-restricted cytotoxic T lymphocytes. The antigens may be a target for immunotherapy. There is, however, little information on the expression of these genes in gastric carcinomas. Therefore, the expression of MAGE genes in gastric carcinomas was evaluated. METHODS: The expression of MAGE-1, MAGE-2, and MAGE-3 genes in tumors and corresponding normal tissue specimens was studied using a reverse-transcription polymerase chain reaction. The results were analyzed according to clinicopathologic factors of the tumor. RESULTS: In the 68 gastric carcinomas studied, MAGE-1, MAGE-2, and MAGE-3 messenger RNA were detected in 41%, 31%, and 38%, respectively. Fifty percent of the gastric carcinomas expressed at least one of the MAGE genes. Messenger RNA for the three MAGE proteins was not detected in normal gastric tissue. MAGE gene expression in gastric carcinomas was not associated with a significant clincopathology of the tumor. However, gene expression was lower in mucinous carcinomas (3 of 10). CONCLUSIONS: MAGE-1, MAGE-2, and MAGE-3 are expressed in a high percentage of gastric carcinomas. These tumor rejection antigens may provide tumor-specific targets for immunotherapy.

Aged↗
PubMed1995

Surgical treatments for oesophageal cancer concomitant with gastric adenoma with severe epithelial atypia.

The various surgical treatments for oesophageal cancer concomitant with gastric adenoma with severe epithelial atypia (SEA) are discussed by presenting three such cases. As gastric adenoma with SEA had been considered to be a precancerous condition but not normally an indication for gastrectomy, we devised an operative strategy of laparotomy and thoracotomy. For Case 1, with early oesophageal cancer and gastric adenoma with SEA in the body of stomach, a laparotomy and local resection of the gastric lesion were carried out prior to thoracotomy in order to determine the safest reconstructive method after measuring the length of the well-nourished gastric tube. In Case 2, with advanced oesophageal cancer, a thoracotomy was first performed to assess the curability of surgery for the oesophageal cancer and a gastric adenoma was removed. In contrast, for Case 3 with advanced oesophageal cancer, and in whom post-operative survival was deemed to be short, a gastric adenoma was not resected. The most appropriate operative methods should thus be decided after careful consideration of the stage of the oesophageal cancer and characteristics of the gastric adenoma.

Adenoma↗
PubMed1995

The heterogeneity of microsatellite instability in multiple gastric cancers.

To obtain a better understanding of the role of genetic instability in developing gastric cancer, it is of great interest to examine microsatellite alterations in synchronous multiple gastric cancers that are thought may have the same genetic background and the same microenvironment of the stomach. We report our experience with two patients with synchronous multiple gastric cancers; patient 1 showed two carcinomas in the stomach, whereas patient 2 showed two carcinomas and two adenomas in the stomach. We examined the DNAs from the two cases for microsatellite instability and expected that the status of microsatellite instability in each tumor from the same stomach would be the same. However, patient 2 revealed heterogeneity in the microsatellite instability, i.e., an early cancer that showed some apparent alterations, whereas the other advanced cancer and two adenomas did not. On the other hand, neither of the two carcinomas in patient 1 showed microsatellite instability. To our knowledge, there has been no previous report of microsatellite instability in multiple gastric cancers. In this report, we describe a case that revealed such a heterogeneity of the microsatellite instability, in which the carcinogenic process of each tumor may undergo different genetic alterations even under the same genetic conditions and background.

Aged↗
PubMed1994

Molecular genotyping for N-acetylation polymorphism in Japanese patients with colorectal cancer.

BACKGROUND: N-acetylation polymorphism has been documented as a representative pharmacogenetic trait, and also has been implicated ecogenetically in an individual's susceptibility to cancer. However, there still remains controversy concerning the association between colorectal cancer and N-acetylation polymorphism. METHODS: A newly established molecular genotyping method using polymerase chain reaction-based restriction fragment length polymorphism to analyze the distribution of polymorphism in a large group of Japanese patients with colorectal cancer was used. RESULTS: Based on an analysis of 234 Japanese patient with colorectal cancer and 329 healthy control subjects, no significant difference was observed in either the distribution of acetylator phenotypes or of allele frequencies between the two groups. In addition, no significant difference in their distribution was found based on the age at which cancer was first detected, the location of tumors, or the histopathologic features. CONCLUSIONS: N-acetylation polymorphism does not appear to be implicated crucially as a genetic trait affecting an individual's susceptibility to colorectal cancer.

Acetylation↗
PubMed1994

A new detection method for the K variant of butyrylcholinesterase based on PCR primer introduced restriction analysis (PCR-PIRA).

The K variant of human butyrylcholinesterase is caused by a G/A transition in the butyrylcholinesterase gene, which neither creates nor destroys any restriction site. In an attempt to detect the K variant both simply and rapidly, we developed a two step method of "PCR primer introduced restriction analysis" (PCR-PIRA). The first step was used to introduce a new Fun4HI site into the normal allele for a screening test, while the second step was performed to create a new MaeIII site on the variant allele for a specific test. This method thus enabled us to distinguish clearly the K variant from the normal allele, and also showed that the frequency of the K variant allele is 0.164 in the Japanese population.

Alleles↗
PubMed1994

Methods in pathology. An improved method for DNA diagnosis of leprosy using formaldehyde-fixed, paraffin-embedded skin biopsies.

To improve the sensitivity of the previously reported polymerase chain reaction (PCR) for the detection of Mycobacterium (M.) leprae in the formaldehyde-fixed, paraffin-embedded tissues, we adapted the PCR designed to amplify an internal 372 bp fragment of a M. leprae-specific repetitive sequence to 39 skin biopsies taken from patients with leprosy of the lepromatous type and tuberculoid type. Crude DNA samples were prepared from tissue sections that were deparaffinized and subjected to proteinase-K digestion without any further treatment for DNA purification. Overcoming a false-negative reaction by an elongation of the period for enzymatic digestion and an appropriate dilution of the samples, an amplification of the target sequence was obtained as a single band with all 39 skin biopsies tested. The fragments specifically amplified by the PCR were subjected to direct sequencing and were confirmed to be identical with an internal 372 bp of M. leprae-specific repetitive sequence. Although in nine of 24 nonleprosy control samples, a false-positive amplification was observed as from one to several bands, they were distinguishable from the specific one by the electrophoretic pattern. This PCR makes up for the classic histological methods used in the diagnosis of leprosy.

Base Sequence↗
PubMed1992

Occlusion as a depth cue in the Wheatstone-Panum limiting case.

We examined the hypothesis (Ono & Wade, 1985) that occlusion of far stimuli by a near one on the same visual line can operate as a depth cue in stereograms containing different numbers of targets in the two eyes. By controlling eye positions, we created conditions in which the visual system could interpret the retinal images as originating from stimuli on the visual axis of one eye and also created other conditions in which the origin of the retinal images was ambiguous. In Experiment 1, we presented two lines to one eye and a single line to the other eye. When the image of the line on the temporal side of the line pair on one retina fused with the image of the single line on the other retina, the nonfused line appeared farther away more often than it did when the image on the nasal side fused. In Experiment 2, we used two differently shaped stimuli. In the condition in which the nonfused stimulus represented an object being occluded, it appeared farther away more often than in the four conditions in which it did not. In Experiment 3, we extended the idea to three different objects. When the middle of the three images fused with the single image, the nonfused stimulus appeared farther when it could be interpreted as being occluded than when it could not. In the condition in which the most temporal image fused with the single image, the nonfused stimuli appeared farther than in the condition in which the most nasal one fused. The results supported the hypothesis that occlusion plays a role in depth perception in the Wheatstone-Panum limiting case.

Adult↗
PubMed1992

The interaction of perceived distance with the perceived direction of visual motion during movements of the eyes and the head.

A horizontally moving target was followed by rotation of the eyes alone or by a lateral movement of the head. These movements resulted in the retinal displacement of a vertically moving target from its perceived path, the amplitude of which was determined by the phase and amplitude of the object motion and of the eye or head movements. In two experiments, we tested the prediction from our model of spatial motion (Swanston, Wade, & Day, 1987) that perceived distance interacts with compensation for head movements, but not with compensation for eye movements with respect to a stationary head. In both experiments, when the vertically moving target was seen at a distance different from its physical distance, its perceived path was displaced relative to that seen when there was no error in perceived distance, or when it was pursued by eye movements alone. In a third experiment, simultaneous measurements of eye and head position during lateral head movements showed that errors in fixation were not sufficient to require modification of the retinal paths determined by the geometry of the observation conditions in Experiments 1 and 2.

Adult↗
PubMed1982

[Psychophysical and vergence responses of normal and stereoanomalous observers to pulse-disparity stimulus].

The relations between psychophysical and oculo-motor responses to retinal disparity were examined in two experiments. Experiment I examined the subject's discriminability of the depth produced by 2 degrees crossed, 2 degrees uncrossed, and zero disparities with the durations of 100 and 1000 ms. As a result, six stereonormal, one crossed stereoanomalous, and one stereoblind observers were identified. In Experiment II, eye movement responses of three subjects with the different types of stereoscopic vision to the disparity pulses were monitored by the photo-electric method. The results of Experiment II indicated that the normal observer showed normal vergence, the crossed stereoanomalous observer showed anomalous convergence, and the stereoblind observer did not show any vergences but saccadic movements. Several theoretical implications of the results are discussed.

Adult↗
PubMedDate not supplied

Pancreaticoduodenectomy under epidural anesthesia without endotracheal intubation for the elderly.

To evaluate the efficacy of a single application of epidural anesthesia without endotracheal intubation for pancreaticoduodenectomy (PD), the data on 30 patients who underwent PD were analyzed for their operative morbidity and mortality. These patients were classified into two groups according to the type of anesthesia performed: 15 received epidural anesthesia alone (Group I) and 15, general anesthesia under endotracheal intubation (Group II). The clinical characteristics of the patients in both groups were comparable at the time of operation, except that Group I included a significantly larger proportion of elderly patients than Group II (p < 0.05). Postoperative pulmonary complications (PPCs) occurred in 5 (33.3%) of the Group II patients, especially in elderly patients who underwent lengthy operations, whereas no such complications occurred in the Group I patients (p < 0.05), even in elderly patients with a long operating time. The curability of the malignant tumors and the incidences of other complications were not significantly different between the two groups. These findings suggest that a single application of epidural anesthesia is effective in preventing PPCs when performing a time-consuming PD, especially in elderly patients.

Aged↗
PubMedDate not supplied

Surgical management of patients with radiation enteritis.

To improve the surgical outcome in patients with radiation enteritis, 18 female cases were analyzed. Out of the 18 cases, 3 (16.7%) were treated conservatively while 15 (83.3%) underwent surgical procedures. Thirteen out of 14 patients (92.8%) with ileus underwent an operation. The overall mortality was 22.2% (4 out of 18 cases). However, no significant difference in the mortality between the operated and non-operated cases was observed. Although an analysis of the 15 operated cases did not reveal any significant factors that might have affected the prognosis, all four patients who underwent a bypass operation showed a good postoperative course, with only one excepting being a patient suffering from malnutrition. Although only a small number of patients were included in this study, these results suggest that 1) surgeons should not hesitate to operate on patients with radiation enteritis demonstrating ileus, and 2) a bypass operation may be one surgical alternative in the presence of massive adhesion or for patients at high risk for a standard operation.

Adult↗