Biomedical subjects

T Oku

Publications and source records attributed to T Oku.

At least 19 recordsLinked to original sources

PubMed2003

Comparison of digestibility and breath hydrogen gas excretion of fructo-oligosaccharide, galactosyl-sucrose, and isomalto-oligosaccharide in healthy human subjects.

OBJECTIVES: To clarify the difference of digestibility in the small intestine among fructo-oligosaccharide (FOS), galactosyl-sucrose (GS), and isomalto-oligosaccharide (IMO) using breath hydrogen test. DESIGN: The first step: screening test of breath hydrogen excretion and FOS tolerance test to select the subjects. The second step: breath hydrogen test of three kinds of oligosaccharides, carried out using precautionary regulations. The ingestion order was 10 g of FOS, GS, and IMO, with increases, at 1-week interval, up to 20 g, respectively. Breath gas was collected before, at 20 min intervals from 40 to 120 min after, and at 30 min intervals from 120 min to 7 h after ingestion of test substance. SETTING: Laboratory of Public Health Nutrition, Department of Nutrition and Health Sciences, Siebold University of Nagasaki, Nagasaki, Japan. SUBJECTS: A total of nine males (average: age 25.7+/-3.5 y, weight 61.9+/-8.8 kg, height 170.0+/-6.0 cm) and 29 females (average: 23.1+/-7.2 y, 52.9+/-5.3 kg, 157.5+/-5.1 cm) from the University of Tokyo and Siebold University of Nagasaki. MAIN OUTCOME MEASURES: Breath hydrogen excretion from end-expiratory gas. RESULT: : Breath hydrogen of FOS was more remarkably excreted than that of GS; that of IMO was slight; and that of AUC (10 g) was significantly different. FOS was 9768+/-3253 ppm, GS was 3662+/-2632 ppm, and IMO was 831+/-1154 ppm. A dose dependence was observed at doses between 10 and 20 g of FOS and GS, and the initial time of 20 g was earlier than that of 10 g. CONCLUSIONS: FOS was not hydrolyzed, GS was slightly hydrolyzed, and IMO was readily hydrolyzed by small intestinal enzymes. H(2) gas reflected fermentability in the large intestine. SPONSORSHIP: Siebold University of Nagasaki.

Adult↗

PubMed2003

Argon plasma coagulation for successful treatment of early gastric cancer with intramucosal invasion.

BACKGROUND: In recent years, there has been an increasing number of cases of early gastric cancer (T1, NX) with intramucosal invasion, which are untreatable by surgical or endoscopic mucosal resection (EMR) because of their high risk. Currently, no adequate treatment is available for such patients. AIM: The main objective of this study was to evaluate whether argon plasma coagulation (APC) is an effective and safe modality for treating early gastric cancer untreatable by surgical resection or EMR. METHODS: The study group comprised 20 men and seven women diagnosed with gastric cancer with intramucosal invasion who were considered poor candidates for surgical resection or EMR due to risk factors such as severe cardiac failure or thrombocytopenia. Irradiation conditions for APC treatment were determined using swine gastric mucosa. We used an argon gas flow of 2 l/min at a power setting of 60 W and a maximum irradiation time of 15 s/cm(2). The follow up period of the 27 patients ranged from 18 to 49 months (median 30 months). RESULTS: All lesions were irradiated easily, including areas anatomically difficult for EMR such as the gastric cardia or the posterior wall of the upper gastric body. In 26 of 27 patients (96%) there was no evidence of recurrence during the follow up period (median 30 months). One patient showed recurrence six months after the treatment but was successfully retreated. No serious complications were found in any of the 27 patients but three patients (11%) experienced a feeling of abdominal fullness. INTERPRETATION: APC is a safe and effective modality for treatment of early gastric cancer with intramucosal invasion untreatable by surgical resection or EMR. However, further observations are necessary to determine the long term prognosis of patients undergoing this treatment.

Adenocarcinoma↗

PubMed2002

Successful treatment of advanced peripheral T-cell lymphoma with an angiocentric growth pattern complicated with hemophagocytic syndrome by high-dose chemotherapy and autologous peripheral blood stem cell transplantation.

Peripheral T-cell lymphomas (PTCL) account for about 10% of all lymphomas in Western countries, respond poorly to therapy, and have short survival with no sustained remission. Furthermore, the complication of hemophagocytic syndrome (HPS) sometimes makes the prognosis of this disease extremely worse. We report here a case of PTCL with an angiocentric growth pattern complicated with HPS successfully treated by high-dose chemotherapy and autologous peripheral blood stem cell transplantation. Our case suggests this approach is an excellent candidate for the treatment of this disease.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed2002

A case of true malignant histiocytosis: identification of histiocytic origin with use of immunohistochemical and immunocytogenetic methods.

We report here an autopsy case of true malignant histiocytosis. The patient was a 67-year-old woman who exhibited fever, wasting, hepatosplenomegaly, and progressive pancytopenia. The bone marrow aspiration disclosed hemophagocytosing cells, which resembled histiocytes. The molecular analysis did not show the clonal gene rearrangement of T-cell receptor or immunoglobulin heavy chain. Although the patient had been started on methylprednisolone pulse therapy and chemotherapy with etoposide, she died from cerebral hemorrhage. The autopsy specimens of spleen and liver showed extensive infiltration of atypical cells, for which histiocytic origin was identified with an immunohistochemical method using monoclonal antibodies against CD11c, CD68, macrophage colony-stimulating factor (M-CSF), M-CSF receptor, lysozyme, antitrypsin and alpha1-antichymotrypsin. Recent investigations have disclosed that in most cases diagnosed as malignant histiocytosis, hemophagocytosis was reactive and not evoked by histiocytic malignancy. True malignant histiocytosis, for which histiocytic origin is confirmed, is extremely rare.

Aged↗

PubMed2002

Surgical treatment of a mixed pineocytoma/pineoblastoma in a 72-year-old patient.

BACKGROUND: Although pineal parenchymal tumours are very rare in elderly patients, we recently successfully treated a 72-year-old male patient. Interestingly, the histology of his pineal parenchymal tumour was mixed pineocytoma/pineoblastoma, which is reported to be extremely rare in aged patients. We present his clinical manifestations, follow-up MRI, surgical treatment, pathological findings, and review the literature. CLINICAL MATERIAL: This 72-year-old man had a mass in the pineal region detected 3 years previously on MRI in February 1996 following symptoms of headache and vertigo. Two years later, he experienced gait disturbance and disorientation. CT scans disclosed obstructive hydrocephalus, and ventriculo-peritoneal shunt placement was then performed. The tumour mass began to enlarge in July 1999 (at age 72). On October 13, 1999, total removal of the pineal region tumour was performed through an occipital transtentorial approach. The postoperative course was uneventful. The pathological diagnosis of the tumour was mixed pineocytoma/pineoblastoma. CONCLUSION: Pineal parenchymal tumours are uncommon in elderly patients, and mixed pineocytoma/pineoblastomas are particularly rare. We followed this patient closely for more than 3.5 years and finally performed total surgical removal of the tumour, with excellent outcome. The present case suggests that a mixed pineocytoma/pineoblastoma tumour is controllable even in elderly patients through careful evaluation and management.

Aged↗

PubMed2001

Regional expression of the splice variants of Kv4.3 in rat brain and effects of C-terminus deletion on expressed K+ currents.

In situ hybridization and RT-PCR analyses have revealed that, among three Kv4.3 splice variants (a, b, and c) with distinct C-terminal cytoplasmic domains, the mRNA for Kv4.3a is abundant in cerebral cortex, cerebellum, olfactory bulb, and medulla oblongata, whereas the mRNA for Kv4.3c is localized mainly to hippocampus. Three new distinct splice variants of Kv4.3 (Kv4.3d, e and f), which consist of 601, 635, and 628 amino acids, respectively, and have distinct C-terminal cytoplasmic domains, were isolated from rat brain by RT-PCR. Kv4.3b, d, e and f were expressed at much lower levels in brain. Mutagenesis which removed 149 amino acids in C-terminal domain of Kv4.3a significantly slowed its rate of recovery from inactivation as measured in heterologous expression in HEK293 cells. Surprisingly, however, neither the rate of inactivation nor voltage dependence of the activation and inactivation were changed.

Amino Acid Sequence↗

PubMed2001

Structural characterization of the metal/glass interface in bioactive glass coatings on Ti-6Al-4V.

Coating Ti-based implants with bioactive materials promotes joining between the prostheses and the bone as well as increasing long-term implant stability. In the present work, the interface between Ti-6Al-4V and bioactive silicate glass coatings, prepared using a simple enameling technique, is analyzed. High-resolution transmission electron microscopy of the glass/alloy interface shows the formation of a reaction layer ( approximately 150 nm thick) composed of Ti5Si3 nanoparticles with a size of approximately 20 nm. This nanostructured interface facilitates the formation of a stable joint between the glass coating and the alloy.

Journal Article↗

PubMed2001

F13459, a new derivative of mycophenolic acid. I. Taxonomy, isolation, and biological properties.

In the course of screening for inhibitors of intracellular trafficking of glycoprotein, a new inhibitor, F13459 was isolated from the culture broth of a Penicillium sp. It was purified using solvent extraction, silica gel, Sephadex LH-20 and ODS column chromatography. From structural analysis, F13459 was a derivative of mycophenolic acid, an inhibitor of inosine 5'-monophosphate dehydrogenase. F13459 inhibited hemagglutinin synthesis of NDV at concentrations more than 25 microg/ml. However, syncytium formation as a result of cell surface expression of F-glycoprotein of NDV was inhibited at concentrations of F13459 lower than those required for appreciable inhibition of glycoprotein synthesis.

Animals↗

PubMed2000

A novel arterial infusion chemotherapy for the treatment of patients with advanced pancreatic carcinoma after vascular supply distribution via superselective embolization.

BACKGROUND: Patients with American Joint Committee on Cancer Stage IV advanced pancreatic carcinoma have been treated by systemic chemotherapy, intraarterial chemotherapy, radiation therapy, and multidisciplinary treatment using a combination of these. However, the outcome has not always been satisfactory. In the current study the authors describe the method and results of a new chemotherapy for advanced pancreatic carcinoma. METHODS: To restrict the blood flow into the pancreas (mainly to the great pancreatic artery and the caudal pancreatic artery), the peripancreatic blood vessels were embolized superselectively with microcoils. In 31 patients with advanced pancreatic carcinoma, the catheter tip for the arterial infusion chemotherapy was placed in the splenic artery just proximal to the branching of the great pancreatic artery when the treatment was given for primary tumors, and in the common hepatic artery when the treatment was given for a metastatic liver lesion. The other end of the catheter was connected to an implanted injection port embedded in the femoral region, and 5-fluorouracil and cisplatin were administered by continuous arterial infusion. RESULTS: Of the 31 patients with advanced pancreatic carcinoma, 23 (74%) underwent hemodynamic change and arterial infusion chemotherapy, with a response rate of 73.9% (complete response rate of 8.7% and a partial response rate of 65.2%) and a mean survival period of 18.26 +/- 10.06 months. The 1-year, 2-year, and 3-year survival rates were 90.9%, 42. 8%, and 18.3%, respectively, with a mean survival period of 19.0 months. Of these 23 patients, the 16 patients with liver metastases had a response rate of 68.8% and a mean survival period of 16.25 +/- 8.35 months, whereas the 7 patients without liver metastases had a response rate of 87.5% and a mean survival period of 22.86 +/- 12.69 months. CONCLUSIONS: In patients with Stage IV advanced pancreatic carcinoma, arterial infusion chemotherapy after hemodynamic change was found to be effective against both primary tumors and metastatic liver lesions. The authors believe that the treatment presented in the current study should be attempted, even in patients with advanced pancreatic carcinoma, as long as the blood vessels for vascular supply distribution exist.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed2000

Hydrolytic activity of alpha-galactosidases against deoxy derivatives of p-nitrophenyl alpha-D-galactopyranoside.

The four possible monodeoxy derivatives of p-nitrophenyl (PNP) alpha-D-galactopyranoside were synthesized, and hydrolytic activities of the alpha-galactosidase of green coffee bean, Mortierella vinacea and Aspergillus niger against them were elucidated. The 2- and 6-deoxy substrates were hydrolyzed by the enzymes from green coffee bean and M. vinacea, while they scarcely acted on the 3- and 4-deoxy compounds. On the other hand, A. niger alpha-galactosidase hydrolyzed only the 2-deoxy compound in these deoxy substrates, and the activity was very high. These results indicate that the presence of two hydroxyl groups (OH-3 and -4) is essential for the compounds to act as substrates for the enzymes of green coffee bean and M. vinacea, while the three hydroxyl groups (OH-3, -4, and -6) are necessary for the activity of the A. niger enzyme. The kinetic parameters (K(m) and Vmax) of the enzymes for the hydrolysis of PNP alpha-D-galactopyranoside and its deoxy derivatives were obtained from kinetic studies.

Aspergillus niger↗

PubMed2000

Estimation of intestinal trehalase activity from a laxative threshold of trehalose and lactulose on healthy female subjects.

OBJECTIVE: The purpose of present study is to investigate small intestinal trehalase activity and the ability to utilize trehalose in healthy Japanese subjects. DESIGN: First, transitory laxative thresholds of trehalose and lactulose were estimated for each of 20 Japanese female subjects. Then, according to the difference between two relative laxative thresholds, small intestinal trehalase activity was estimated for each individual subject. Trehalose tolerance tests were then carried out on two groups with lower or higher trehalase activity. SETTING: Department of Nutrition, Faculty of Medicine, University of Tokyo. RESULTS: When 30 g of trehalose were administered orally to six subjects with the low trehalase activity, blood glucose and insulin levels scarcely elevated after loading. In contrast, when 50 g of trehalose were administered orally to six subjects with high trehalase activity, blood glucose levels quickly and significantly increased 30 min after loading (P<0.01) and slightly decreased after 60 min, reducing quickly to a fasting level 90 min after loading. Blood insulin levels also peaked 30 min after administration. Yet, decreases in blood insulin levels in the trehalose loading experiment were delayed in comparison with the same amount of glucose ingestion, and peak insulin levels were significantly lower than those with glucose ingestion (P<0.01). CONCLUSION: We conclude that subjects with high trehalase activity can effectively utilize trehalose which is ingested from the diet, and when a subject with low trehalase activity ingests a large amount of trehalose, a portion of the trehalose might pass through the small intestine and reach the large intestine where it is fermented completely by colonic bacteria. Therefore, the apparent digestibility of trehalose is similar in both subjects with low and high trehalase activities.

Adult↗

PubMed2000

Digital high-resolution electron microscopy of atomic disordering in YB56

Despite of the difficulty in determining the atomic arrangement of light elements and doping atoms in the solid clusters, it is believed that the high-resolution images should have 'some' information on disordering, ordering, and doping atomic positions in these materials. In the present work, the information for disordering of atomic positions in YB56 was obtained from digital high-resolution images. The arrangement of Y atoms was also directly imaged and quantified. The present work indicates that the atomic detection by digital high-resolution images is very useful for evaluation of local structure in the ceramic materials with light elements such as boron.

Journal Article↗

PubMed2000

Modulated structure of Ag2SnO3 studied by high-resolution electron microscopy

The modulated structure of Ag2SnO3, disilver tin trioxide, was investigated by high-resolution electron microscopy and electron diffraction along four different directions. Electron diffraction showed an incommensurate one-dimensional modulated structure with a modulation wavevector of 1/6.4a*. High-resolution images showed a large number of superstructure domains with the size range 10-100 nm and orientations related by hexagonal rotation. The modulation was determined to be displacements along the c axis of the Ag atoms both in octahedral and linear coordination. An approximate structure model with a commensurate sixfold superstructure, with an orthorhombic cell (P2(1)2(1)2(1), a = 2.922, b = 1.267, c = 0.562 nm), is proposed. Calculated images and electron diffraction patterns, based on this model, agree well with experimental observations.

Journal Article↗

PubMed2000

Structure of cytochrome c6 from the red alga Porphyra yezoensis at 1. 57 A resolution.

The crystal structure of cytochrome c(6) from the red alga Porphyra yezoensis has been determined at 1.57 A resolution. The crystal is tetragonal and belongs to space group P4(3)2(1)2, with unit-cell parameters a = b = 49.26 (3), c = 83.45 (4) A and one molecule per asymmetric unit. The structure was solved by the molecular-replacement method and refined with X-PLOR to an R factor of 19.9% and a free R factor of 25.4%. The overall structure of cytochrome c(6) follows the topology of class I c-type cytochromes in which the heme prosthetic group covalently binds to Cys14 and Cys17, and the iron has an octahedral coordination with His18 and Met58 as the axial ligands. The sequence and the structure of the eukaryotic red algal cytochrome c(6) are very similar to those of a prokaryotic cyanobacterial cytochrome c(6) rather than those of eukaryotic green algal c(6) cytochromes.

Amino Acid Sequence↗

PubMed2000

Leukocyte integrin-dependent and antibody-independent cytotoxicity of macrophage against allografts.

Macrophages (Mphis), but not T cells, infiltrating into the rejection site of either i.p. allografted Meth A (H-2d) fibrosarcoma cells in C57BL/6 (B6) (H-2b) mice or BALB/c (H-2d) skin onto B6 mice are cytotoxic against allografts with H-2d specificity. To determine the mechanisms of specific killing of allografts by allograft-induced Mphi (AIM), we raised approximately 5,000 rat monoclonal antibodies (mAbs) against AIM and selected three of them (R1-73, R2-40 and R1-34), each of which inhibited cytotoxic activity against allografts in a dose-dependent manner. The antigens recognized by R1-73, R2-40 and R1-34 mAbs were defined by immunoprecipitation and Western blot analyses as CD11a, CD18 and CD11b, respectively; and the allografts expressed CD54, a ligand of CD11a or CD11b, suggesting leukocyte integrin-dependent killing. Although Ab-dependent cellular cytotoxicity has been recognized as a mechanism of specific killing by Mphis, the infiltration of AIM into the rejection site of allografts far (approximately 6 days) preceded the appearance of serum IgG Ab specific for the allograft. AIM exhibiting full cytotoxic activity against allografts was also induced in the transplantation site of Fcgamma receptor knockout [(B6x129) F1] mice as well as B10.D2 (H-2 compatible with allograft) and B6-xid (X-linked immunodeficiency with B cell-specific defect) strains of mice. In the latter two strains of mice, the levels of serum IgG Ab to the allograft were negligible. Moreover, the cytotoxic activity of AIM against allografts was not affected by pretreatment of the cells with anti-mouse IgG serum, suggesting Ab-independent cytotoxicity.

Animals↗

PubMed2000

Characterization and amino acid sequences of cytochromes c6 from two strains of the green alga Chlorella vulgaris.

Cytochromes c6 from the green algae Chlorella vulgaris CK-5 (CK5cyc6) and C. vulgaris CK-22 (CK22cyc6) were characterized and their amino acid sequences were analyzed. CK5cyc6 had a molecular mass of 9.3 kDa, isoelectric points of 3.0 (reduced) and 3.6 (oxidized), and a redox potential of +362 mV at pH 7.0. CK22cyc6 had a molecular mass of 9.5 kDa, isoelectric points of 2.9 (reduced) and 3.5 (oxidized), and a redox potential of +355 mV at pH 7.0. The absorption spectra of both cytochromes c6 showed 4 maxima in reduced form, and 2 maxima and a weak peak at 695 nm in oxidized form. The pyridine ferrohemochrome spectra indicated that their prosthetic group was heme c. These physicochemical properties were similar to those of other algal cytochromes c6. The amino acids (88 residues) of CK5cyc6 and CK22cyc6 were sequenced and the sequence motif -CXXCH-, which is typical of the heme-binding site of c-type cytochrome, was clearly confirmed in both cytochromes. Twenty-six amino acid residues were substituted, and the similarity score of each of them was 70.45%.

Algal Proteins↗

PubMed2000

Cloning and molecular characterization of hrpX from Xanthomonas axonopodis pv. citri.

The hrpX gene of plant pathogenic Xanthomonas species is essential for pathogenicity on host plants and to cause hypersensitive reaction on non-host plants. We cloned and analyzed a hrpX homologue, designated hrpXct, of X. axonopodis pv. citri, a pathogen of citrus canker. The open reading frame of hrpXct has 1431 bp in nucleotides which has a coding capacity of 476 amino acid residues with a molecular mass of 52.4 kDa. The predicted amino acid sequence of HrpXct has 90% identity to the AraC family type transcriptional activator protein HrpXc of X. campestris pv. campestris, 95% to HrpXo of X. oryzae pv. oryzae and 97% to X. vesicatoria. These findings clearly indicate and confirm that the structure of the hrpX genes in plant pathogenic Xanthomonas species is highly conserved.

Amino Acid Sequence↗

PubMed2000

[Dissecting aneurysm of the middle cerebral artery: case report].

We present a surgical case of a dissecting aneurysm of the right middle cerebral artery associated with subarachnoid hemorrhage and intracranial hemorrhage. A 61-year-old woman with consciousness disturbance and left hemiplegia was referred to our hospital. She had suffered severe headache for a week. CT scan showed a subarachnoid hemorrhage in the right Sylvian fissure and intracranial hemorrhage in the right putamen. The right carotid angiogram revealed string sign in M1 portion and occlusion at M2 lower branch of the right middle cerebral artery. On the 12th day, we undertook surgery to confirm whether it was a dissecting aneurysm or not. In the operation, it was reddish in the M1 portion corresponding to the "string sign" and dark-purplish in the lower M2 portion corresponding to an "aneurysm-like lesion". To prevent bleeding, the arterial wall in the M1 portion was coated using muscle. Though the left hemiplegia was unchanged, the postoperative course was uneventful. The patient was transferred to another hospital and underwent rehabilitation. There has been no reccurrence during the four years since surgery. The middle cerebral artery dissecting aneurysm is extremely rare. We presented this case with review of the literature.

Aortic Dissection↗