Biomedical subjects

Kimihiko Sato

Publications and source records attributed to Kimihiko Sato.

10 recordsLinked to original sources

PubMed2006

Self-organized interconnect method for molecular devices.

Lack of an appropriate method for wiring molecules that have controlled functions and structures has been a barrier for the development of molecular devices. We developed an interconnect method to program three kinds of component molecules with their own functions and to wire a molecular device in a self-organized manner. By using the interconnect method we developed, we produced conductive wires and optical switching devices and have demonstrated their device functions. Our interconnect method allows us to control various molecular device characteristics by combining the three molecules.

Journal Article↗

PubMed2006

Molecular cloning and characterization of an enzyme hydrolyzing p-nitrophenyl alpha-D-glucoside from Bacillus stearothermophilus SA0301.

Bacillus stearothermophilus SA0301 produces an extracellular oligo-1,6-glucosidase (bsO16G) that also hydrolyzes p-nitrophenyl alpha-D-glucoside (Tonozuka et al., J. Appl. Glycosci., 45, 397-400 (1998)). We cloned a gene for an enzyme hydrolyzing p-nitrophenyl alpha-D-glucoside, which was different from the one mentioned above, from B. stearothermophilus SA0301. The k(0)/K(m) values of bsO16G for isomaltotriose and isomaltose were 13.2 and 1.39 s(-1).mM(-1) respectively, while the newly cloned enzyme did not hydrolyze isomaltotriose, and the k(0)/K(m) value for isomaltose was 0.81 s(-1).mM(-1). The primary structure of the cloned enzyme more closely resembled those of trehalose-6-phosphate hydrolases than those of oligo-1,6-glucosidases, and the cloned enzyme hydrolyzed trehalose 6-phosphate. An open reading frame encoding a protein homologous to the trehalose-specific IIBC component of the phopshotransferase system was also found upstream of the gene for this enzyme.

Amino Acid Sequence↗

PubMed2005

Evaluating benign and malignant musculoskeletal lesions with radionuclide angiography and SPECT using Tc-99m MIBI.

PURPOSE: The purpose of this study was to evaluate the use of radionuclide angiography and single photon emission computed tomography (SPECT) using Tc-99m hexakis-2-methoxyisobutylisonitrile (Tc-99m MIBI) for analyzing musculoskeletal lesions. MATERIALS AND METHODS: Radionuclide angiography and SPECT using Tc-99m MIBI were performed in 36 patients with various soft tissue and bone pathologies (18 benign and 18 malignant lesions). The ratio of the counts of the lesion to that of the contralateral normal area was calculated from the region of interest drawn on the MIBI scan. The MIBI-uptake ratio was calculated using SPECT and the MIBI-perfusion index was calculated using radionuclide angiography. RESULTS: The MIBI-uptake ratio in malignant lesions (4.80 +/- 4.43) was significantly higher (P < 0.05) than that in benign lesions (1.83+/-2.48). The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of the MIBI-uptake ratio for malignant lesions were 72%, 83%, 78%, 81%, and 75%, respectively. The MIBI-perfusion index in malignant lesions (17.68 +/- 21.19) was significantly higher (P < 0.05) than that in benign lesions (2.25 +/- 2.56). The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of the MIBI-perfusion index for malignant lesions were 87%, 75%, 81%, 77%, and 86%, respectively. CONCLUSIONS: The MIBI-uptake ratio and MIBI-perfusion index using Tc-99m MIBI can yield important additional information with which to differentiate musculoskeletal lesions.

Adolescent↗

PubMed2003

Unprecedented double C-C bond cleavage of a cyclopentadienyl ligand.

Double C-C bond cleavage of a cyclopentadienyl ligand proceeded to titanacyclopentadienes when 2 equiv of nitriles were added and the resulting two-carbon unit and three-carbon unit were converted into a benzene derivative and a pyridine derivative, respectively, in one-pot.

Journal Article↗

PubMed2003

Analysis of genetic alterations, classified according to their DNA ploidy pattern, in the progression of colorectal adenomas and early colorectal carcinomas.

DNA aneuploidy is a biological marker of the oncogenic potential of colorectal adenomas. The accumulation of genetic alterations of cancer-related genes is also essential for colorectal carcinogenesis. However, it is unclear whether there is any relationship between these genetic alterations and the DNA ploidy of colon tumour cells in the progression of colorectal adenomas and early colorectal carcinomas. Here we have studied the DNA ploidy state and genetic alterations occurring in colorectal tumours using the crypt isolation technique. Crypts isolated from a total of 106 colorectal tumors (adenoma, 93; early carcinoma, 13) were examined using a combination of flow cytometric analysis of DNA content, polymerase chain reaction-microsatellite assay, and single-strand conformation polymorphism assay for evidence of chromosomal allelic imbalance (AI; 17p; 5q; 18q) or p53 gene mutation. In addition, we examined microsatellite instability (MSI) with BAT 26 primer sets. DNA multiploidy was infrequently detected in colorectal adenomas (15.1%), in contrast to early carcinomas (46.2%). There was a significant difference in the incidence of AI of chromosome 18q between diploid adenomas and aneuploid populations of multiploid adenomas (18.1% vs 57.1%, p = 0.0043). Mutation of p53 was also found more frequently in aneuploid populations of early multiploid colorectal carcinomas than in early diploid colorectal carcinomas (66.7% vs 0%, p = 0.021). MSI was found in only 2 of 93 adenomas, with no MSI detected in early colorectal cancers. The two MSI-positive adenomas were diploid. We subdivided multiploid adenomas into two groups: those with a low or a high DNA index (DI). The incidence of genetic alterations of high-DI adenomas did not differ from those of low-DI adenomas. Allelic imbalance involving loci on chromosome 18q and mutations of p53 seems to be associated with the progression of diploidy to multiploidy in colorectal tumours. On the other hand, MSI may be associated with the development of some diploid tumours. In addition, the incidence of genetic alterations in the colorectal adenomas that we examined appears to be independent of the tumour's DNA index.

Adenoma↗

PubMed2002

Molecular validation of the modified Vienna classification of colorectal tumors.

Although the Vienna classification has been introduced to resolve discrepancies in histological diagnoses of colorectal tumors between Western and Japanese pathologists, practical applications of this classification scheme have been problematic because invasion of the lamina propria of tumor cells is often difficult to recognize. Therefore, the following refinements of the classification criteria are needed: category 3, low-grade adenoma/dysplasia; category 4, intramucosal borderline neoplasia; 4-a, high-grade adenoma/dysplasia; 4-b, well-differentiated adenocarcinoma; category 5, definite carcinoma; 5-a, intramucosal moderately-differentiated adenocarcinoma; and 5-b, submucosal carcinoma. We attempted to test whether molecular genetic alterations are related to the modified classification scheme and whether they may help to further categorize the various intramucosal neoplasia grades of colorectal tumors. Two-hundred-thirty-two colorectal tumors were examined using flow cytometric analysis of DNA content, polymerase chain reaction microsatellite assays, and single-strand conformational polymorphism assays to detect abnormalities of DNA content, chromosomal allelic loss, and Ki-ras and p53 gene mutations. Microsatellite instability (MSI) was also examined. Frequencies of genetic alterations and DNA aneuploid states increased with an increase in the grade assigned according to the modified Vienna classification. MSI was a rare event in colorectal adenomas and their frequency of MSI did not correlate with tumor grade. The combined genetic and DNA ploidy data support the conclusion that analysis of genetic alterations and DNA aneuploid states may help in appropriate categorization of colorectal tumors according to the modified Vienna scheme. In addition, MSI-positive tumors may represent a specific subtype of colorectal adenomas.

Adenocarcinoma↗

PubMed2002

[Feasibility of early ambulation three hours after transfemoral angiography using a 4 French sheath].

PURPOSE: Our objective was to evaluate the feasibility of early resumption of ambulation 3 hours after transfemoral angiography using a 4 French sheath. SUBJECTS AND METHODS: This prospective study was carried out in a selected group of men and women without impaired blood clotting (prothrombin time > 15 sec) or thrombocytopenia (platelet < 55,000/mm3). The subjects consisted of 66 men and 34 women with a mean age of 62.3 years (range 27-90 years). Incidences of rebleeding or hematoma at the site of femoral catheter insertion were investigated before and after ambulation. Rebleeding was defined as bleeding that required recompression. Hematoma was defined as a palpable, firm collection of subcutaneous blood. RESULTS: Of 100 patients who resumed full ambulation after three hours of bed rest, none (0%) had acute groin hematoma and only three (3%) showed rebleeding that had to be manually compressed. The remaining 97 patients (97%) had no problem after ambulation. CONCLUSION: Supervised resumption of ambulation 3 hours after angiography with a 4 French sheath is safe and feasible in most ambulatory patients undergoing transfemoral angiography.

Adult↗

PubMedDate not supplied

Dual balloon-occluded retrograde transvenous obliteration of gastric varix draining into the left adrenal vein and left inferior phrenic vein.

A 66-year-old woman with a gastric varix, draining into a dilated left adrenal vein and a left inferior phrenic vein, was treated with dual balloon-occluded retrograde transvenous obliteration (B-RTO). Under balloon occlusion of the left adrenal vein and the left inferior phrenic vein, retrograde injection of a sclerosant (5% ethanolamine oleate) into the gastric varix was performed. Two weeks later, disappearance of flow in the gastric varix was confirmed on endoscopic ultrasound examination.

Adrenal Glands↗

PubMedDate not supplied

The influence of radiofrequency ablation on hepatic vessels in porcine liver.

BACKGROUND/AIMS: The objective of this study was to clarify the influence of radiofrequency ablation on the portal and hepatic vein. METHODOLOGY: Hepatic radiofrequency ablation was performed on 18 swine (mean weight, 22 kg). The livers were removed immediately, 1 week or 3 weeks following ablation. Vessel patency and diameter were determined by computed tomography, and the severity of endothelial injuries was determined histopathologically. RESULTS: The patency rate for portal and hepatic veins with diameters less than 3.0 mm decreased sequentially. At three weeks following ablation, the patency rate for vessels with diameters more than 3.0 mm was significantly higher (P<0.05) compared to those with diameters less than 2.0 mm. In portal and hepatic veins contiguous to ablated hepatic parenchyma, the endothelium with intimal thickening was found at 1 to 3 weeks following ablation, although its detection rate was decreased until 3 weeks. CONCLUSIONS: The portal and hepatic vein with diameters more than 3.0 mm in radiofrequency lesions maintained high patency. The endothelium seems to play an important role for maintaining vessels patency and the distal hepatic tissue following ablation. We believe that this maintained vascular patency may be the advantage of radiofrequency ablation over the PEIT.

Animals↗

PubMedDate not supplied

Upper gastrointestinal disorders induced by non-steroidal anti-inflammatory drugs.

BACKGROUND/AIMS: We examined the characteristics of upper gastrointestinal (GI) disorders induced by non-steroidal anti-inflammatory drugs (NSAIDs). METHODOLOGY: The questionnaire investigation was performed over a five-year period. RESULTS: A study was performed on 354 patients (161 men and 193 women with mean ages of 66.0 and 70.7 years, respectively) who developed NSAID associated upper GI disorders: 21 patients had acute gastric mucosal lesion (AGML), 212 had gastric ulcer, 63 had duodenal ulcer, 17 had gastroduodenal ulcers and 41 other cases. About 75% of patients received NSAIDs for orthopedic conditions. Sixty percent of gastric disorders induced by NSAIDs affected the antrum or angulus of the stomach. The incidence of disorders of the gastric antrum was significantly higher in women than in men whilst the incidence of disorders on the gastric angulus was significantly higher in men than in women (p<0.05). The proportion of patients with GI symptoms was significantly lower in patients over 65 years old than in those under 65 years old (p<0.05). The time taken to achieve the healing stage was significantly longer in patients with greater than 3 months NSAID ingestion compared to patients that had received NSAIDs for less than 3 months (p<0.05). CONCLUSIONS: We should examine the association between upper GI disorders induced by NSAIDs and H. pylori as well as the rate of GI disorders induced by new Cox-2 inhibitors.

Adult↗