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Biomedical subjects

S Kitamura

Publications and source records attributed to S Kitamura.

At least 163 records · Page 9Linked to original sources
PubMed1999

Comparative Surface Studies at Atomic Resolution with Ultrahigh Vacuum Variable-Temperature Atomic Force and Scanning Tunneling Microscopes.

: With the ultrahigh vacuum variable-temperature scanning tunneling microscope (UHV-VT-STM), atomic-level observation has been achieved. An ultrahigh vacuum atomic force microscope (UHV-AFM) has also been developed, with success in obtaining atom images where observation in noncontact (NC) mode with a frequency modulation (FM) detection method was attempted. Using the FM detection method in the constant oscillation amplitude of the cantilever excitation mode, we have obtained atomic-resolution images of Si(111) 7 x 7 structures and Si(100) 2 x 1 structures and other structures together with STM images in an ultrahigh vacuum environment. Also shown here are contact potential difference (CPD) images using the NC-AFM method.

Journal Article↗
PubMed1999

Interaction between surface active drug (FK906:rennin inhibitor) and cyclodextrins in aqueous solution.

The aggregation behavior of FK906, which is a peptide like hypertensive agent, in aqueous solution was studied by static light scattering, 1H-nuclear magnetic resonance (NMR), and surface tension. These experiments showed a clear critical micelle concentration (cmc) at around 6.3 x 10(-3) to 1.3 x 10(-2) M of FK906 aqueous solution. The result of 1H NMR experiments revealed that FK906 aggregates primarily by hydrophobic interactions involving the benzyl moiety. The Debye plots from light-scattering studies showed that the apparent molecular weight of aggregated FK906 molecule is 1670 which corresponds to 2-3 molecules of FK906. The effect of alpha- and beta-cyclodextrins on the surface tension of FK906 aqueous solution was investigated. It appeared that the addition of alpha-cyclodextrin showed very small shift of cmc, but that of beta-cyclodextrin shifted the cmc to much higher concentration. The investigation on the surface tension of FK906 aqueous solution in the presence of beta-cyclodextrin indicated that FK906 forms a 1:1 complex with beta-cyclodextrin. On the basis of these experiments, it appears that beta-cyclodextrin has an ability to change the surface active property of FK906 in its aqueous solution. Therefore, it is expected that the addition of beta-cyclodextrin to FK906 aqueous solution may prevent the adsorption onto container walls and/or reduce the local irritancy.

Antihypertensive Agents↗
PubMed1999

Cytokine-induced neutrophil chemoattractant in a rat model of lipopolysaccharide-induced acute lung injury.

To elucidate the role of major chemotactic factors, cytokine-induced neutrophil chemoattractant (CINC), leukotriene B4 (LTB4) and C5a in lipopolysaccharide (LPS)-induced acute lung injury in rat, we employed three reagents: anti-CINC-1 antibody, an LTB4 receptor antagonist (ONO-4057) and an anti-complementary agent (K-76COONa). Rats were divided into five groups: (1)control group; (2) LPS group, which received intratracheal instillation of LPS (100 microg/kg); (3) Anti-CINC group, which received intratracheal coinstillation of LPS with anti-CINC-1 antibody (1 mg/kg); (4) LTB4-Ra group, which received intravenous ONO-4057 (10 mg/kg) prior to intratracheal LPS; (5) Anti-C5a group, which received intravenous K-76COONa (100 mg/kg) prior to intratracheal LPS. The number of neutrophils in bronchoalveolar lavage (BAL) fluids 6 h after LPS instillation was significantly reduced in the Anti-CINC group, however, no reduction was found in either the LTB4-Ra group or Anti-C5a group. The levels of CINC-1, CINC-2alpha and CINC-3 in BAL fluids were significantly higher in the LPS group than in the saline-instilled control group. In vitro, the production of CINC-1 and CINC-3 from LPS-stimulated macrophages was significantly elevated compared to unstimulated macrophages 6 h later. The increase in CINC-2alpha production was markedly less than that of CINC-1 or CINC-3. These results indicate that CINCs, especially CINC-1 and CINC-3 play an important role in the recruitment of neutrophils to the lung in LPS-induced acute lung injury.

Albumins↗
PubMed1999

Soluble intercellular adhesion molecule-1 as an early detection marker for radiation pneumonitis.

To investigate the role of intercellular adhesion molecule-1 (ICAM-1) in the pathogenesis of radiation pneumonitis and to determine whether the measurement of soluble ICAM-1 (sICAM-1) levels is useful for predicting the onset of pneumonitis, the levels of sICAM-1 were measured in serum and bronchoalveolar lavage (BAL) fluids from patients with lung malignancy who received radiotherapy. A total of 30 patients were irradiated with a total dose of approximately 60 Gy. Blood samples were taken before, midway and after radiotherapy. BAL was also performed before and after radiotherapy in seven cases. The sICAM-1 concentration was measured using an enzyme-linked immunosorbent assay kit with two different monoclonal antibodies. Twelve out of 30 cases developed radiation pneumonitis (pneumonitis group), and the other cases did not (nonpneumonitis group). Serum levels of sICAM-1 after radiotherapy were significantly elevated in the pneumonitis group, but not in the nonpneumonitis group. In some of the cases in the pneumonitis group, sICAM-1 levels began to increase at an early phase of irradiation. In one case of pneumonitis in which BAL was performed, the total cell count and the number of lymphocytes increased markedly, as did the level of sICAM-1 in BAL fluid. These findings suggest that intercellular adhesion molecule-1 may play an important role in the development of radiation pneumonitis and that soluble intercellular adhesion molecule-1 may be a useful marker for the early detection of radiation pneumonitis.

Biomarkers↗
PubMed1999

Proportions of various endocrine cells in the pancreatic islets of wood mice (Apodemus speciosus).

Using wood mice (Apodemus speciosus) captured in the wild in Niigata, we analysed the proportion of various endocrine cells in pancreatic islets for both immunohistochemical and microscopic characteristics. In both the dorsal and ventral portions of the pancreas, the centre of the pancreatic islets was occupied predominantly by insulin-positive (B) cells, surrounded by glucagon-positive (A), somatostatin-positive (D), and pancreatic-polypeptide-positive (PP) cells. Although the proportions of the various endocrine cells in pancreatic islets varied from one mouse to the next, in most animals B cells accounted for more than half of all endocrine cells. Dorsal and ventral portions of the pancreas differed in the proportions of various endocrine cells, specifically, in the A-to-PP cell ratio: the proportion of PP cells higher in the ventral portion. The same tendency is seen in humans, rats and mice. Microscopic examinations revealed morphologically distinct secretory granules in A, B and D cells. The morphology of these granules was similar that of secretory granules found in rats and mice.

Animals↗
PubMed1999

A diary form quality of life questionnaire for Japanese patients with lung cancer and summarization techniques for longitudinal assessment.

The aim of this study was to confirm the validity and reliability of a new diary-type quality of life (QOL) self-rating questionnaire tailored for use by Japanese inpatients with lung cancer receiving chemotherapy. Two kinds of summary statistics were tested in QOL analysis. The questionnaire has a four-scale structure; physical, psychological, daily activity and global scales. Fifty-three patients were enrolled to test the reliability and validity. Summary statistics were assessed using indices of the area under the curve (AUC) and the maximum fluctuations of QOL scores (Dif max) in patients receiving cisplatin or carboplatin. The questionnaire had satisfactory reliability and validity. The physical, psychological and global scales scores changed to the worst levels after treatment, continuing for 1 week in the cisplatin group, whereas those of the carboplatin group began to worsen from day 3, but returned to prechemotherapy levels by day 9. The cisplatin group showed significant decrease of QOL compared with the carboplatin group in the AUC of psychological and two global scales, in the Dif max of psychological and linear analogue global scales. These results suggested that this questionnaire reflects differences in the influence of chemotherapy, and that AUC and Dif max may be useful indices for the analysis of QOL as measures to assess multidimensional QOL.

Adult↗
PubMed1999

Brachial plexus birth injuries: anaesthesia for surgical nerve reconstruction and preoperative myelography and computed tomographic myelography.

Surgical nerve reconstruction for brachial plexus birth injuries and preoperative myelography and computed tomographic (CT) myelography require special anaesthetic considerations. Anaesthesia and medical records were retrospectively reviewed for the infants who underwent myelography, CT myelography (n=37) and microsurgical nerve reconstruction (n=34) at our institution from January 1993 to August 1996. Anaesthetic considerations include long duration of operation, perioperative respiratory complications and plaster application which makes reintubation difficult. Myelography for diagnosis requires a specific positioning of the patient with the head fixed in a midline and prone position.

Anesthesia, Inhalation↗
PubMed1999

A new modification of anaesthesia mask for fibreoptic intubation in children.

We made a paediatric anaesthesia mask suitable for fibreoptic intubation by modifying a commercially available disposable mask with a ventilation port (Vent port) on a side. We added a large fibreoptic port (FO port, 22 mm in ID) in the middle of the mask to allow the passage of all sizes of paediatric tracheal tubes. This FO port was covered with an elastic rubber membrane to allow air-tight fibrescopic manipulation Fibreoptic intubation was performed safely through the FO port under continuous manual ventilation with anaesthetic gases via a Vent port connected to the breathing circuit. We succeeded in tracheal intubation in several infants and children with difficult airway in less than ten min, mainly via the nasotracheal route. This fibreoptic mask provides a safer technique for fibreoptic intubation in patients with difficult airways, especially in infants and small children.

Anesthesia, Inhalation↗
PubMed1999

Eicosapentaenoic acid modulates arachidonic acid metabolism in rat alveolar macrophages activated by silica.

Eicosapentaenoic acid (EPA) was used to modulate the activation of alveolar macrophages, to examine its potential anti-inflammatory effect in addition to its anti-arteriosclerotic or anti-thrombotic effects. Wistar strain rat alveolar macrophages (2 x 10(6) cell) obtained by bronchoalveolar lavage were preincubated with EPA (0-20 microM), and further incubated with 1 mg of silica for 90 min. Leukotriene (LT) B4 and LTB5 of the supernatant were analyzed by reverse phase HPLC. EPA inhibited the production of LTB4 dose-dependently. The production of LTB5, a metabolite from EPA, was increased at low concentrations of EPA (0-10 microM) and decreased at high concentrations (>10 microM). These results suggest that EPA is competitive with arachidonic acid (AA) at low concentrations, and that EPA may inhibit AA metabolism via inhibition of 5-lipoxygenase or phospholipase A2 at high concentrations.

Animals↗
PubMed1999

Identification of human cytochrome P450 isoforms involved in the metabolism of S-2-[4-(3-methyl-2-thienyl)phenyl]propionic acid.

1. To identify the cytochrome P450 (CYP) isoenzymes responsible for the major metabolic pathways of S-2-[4-(3-methyl-2-thienyl)phenyl] propionic acid (S-MTPPA) in man, the metabolism of S-MTPPA was examined using human liver microsomes and microsomes containing cDNA-expressed CYP isozymes (CYP1A2, 2A6, 2B6, 2C9-Arg, 2C9-Cys, 2C19, 2D6-Val, 2E1 and 3A4). 2. S-MTPPA was mainly oxidized to the 5-hydroxylated metabolite of the thiophene ring (MA6) with human liver microsomes in the presence of NADPH. The formation of MA6 was inhibited by SKF 525-A, suggesting that CYP plays role in the formation of MA6. 3. Eadie-Hofstee plots for the 5-hydroxylation of S-MTPPA in the range 5-100 microM were linear for all samples studied, suggesting that the formation of MA6 by human liver microsomes follows simple Michaelis-Menten kinetics. Apparent Vmax = 1.42+/-0.64 nmol/min/mg protein; Km = 12+/-5 microM. 4. Among the CYP inhibitors examined (alpha-naphthoflavone, sulphaphenazole, omeprazole, quinidine and troleandomycin), sulphaphenazole (a CYP2C9 inhibitor) showed the most potent inhibitory effect on the 5-hydroxylation of S-MTPPA by human liver microsomes. 5. When incubated with microsomes containing cDNA-expressed CYP isozymes, S-MTPPA was substantially oxidized to MA6 only by CYP2C9. 6. These results suggest that formation of the major metabolite of S-MTPPA, MA6, in human liver microsomes is catalysed predominantly by a single CYP isoenzyme, namely CYP2C9.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1999

Microsomal carbonyl reductase responsible for reduction of 4-phenyl-3-buten-2-one in rats.

trans-4-Phenyl-3-buten-2-one (PBO), a flavoring additive, was transformed to the carbonyl-reduced product, trans-4-phenyl-3-buten-2-ol (PBOL) by rat liver microsomes, but not by liver cytosol, in the presence of NADH or NADPH. PBOL formed was identified by comparison with an authentic sample. The reductase activity was not inhibited by quercitrin, an inhibitor of cytosolic carbonyl reductase. The carbonyl reduction product of PBO by liver microsomes was identified as the R-enantiomer of PBOL by HPLC analysis. Rat blood also exhibited the carbonyl reductase activity in the presence of NADH or NADPH, but to a lesser extent.

Alcohol Oxidoreductases↗
PubMed1999

Variation of hepatic methotrexate 7-hydroxylase activity in animals and humans.

This study deals with individual and species variations in the converting activity of methotrexate (MTX) to 7-hydroxymethotrexate in animals and humans. When MTX 7-hydroxylase was assayed in six human liver cytosols, a 48-fold range of intersubject variation of the activity was observed. The variations were correlated to the concentrations of aldehyde oxidase activity in human subjects assayed with benzaldehyde as a substrate. Species differences of liver MTX 7-hydroxylase activity were also observed. The activity was highest in rabbits, followed by rats, hamsters, and monkeys but was undetectable in dogs. Strain differences of MTX 7-hydroxylase activity based on aldehyde oxidase activity were also observed in rats and mice. The results suggest that aldehyde oxidase functions as MTX 7-hydroxylase in livers of animals and humans, and the observed differences of MTX 7-hydroxylase activity are due to variations in the amount of aldehyde oxidase present.

Adult↗
PubMed1999

Pseudoenzymatic reduction of N-hydroxy-2-acetylaminofluorene to 2-acetylaminofluorene mediated by cytochrome P450.

N-hydroxy-2-acetylaminofluorene (N-OH-AAF) was reduced to 2-acetylaminofluorene by rat liver microsomes in the presence of both NAD(P)H and FAD under anaerobic conditions. The microsomal reduction proceeds as if it were an enzymatic reaction. However, when the microsomes were boiled, the activity was not abolished, but was enhanced. The activity was also observed with cytochrome P450 2B1 alone, without NADPH-cytochrome P450 reductase, in the presence of these cofactors. Hematin also exhibited a significant reducing activity in the presence of both a reduced pyridine nucleotide and FAD. The activities of microsomes, cytochrome P450 2B1 and hematin were also observed upon the addition of photochemically reduced FAD instead of both NAD(P)H and FAD. The microsomal reduction of N-OH-AAF appears to be a non-enzymatic reaction by the reduced flavin, catalyzed by the heme group of cytochrome P450.

2-Acetylaminofluorene↗
PubMed1999

A case of interleukin-6-producing malignant fibrous histiocytoma originating in the heart.

Primary cardiac malignant fibrous histiocytoma is extremely rare and its pathophysiological characteristics remain largely unknown. We treated a female patient with persistent fever and disseminated intravascular coagulation. Since ultrasonic echocardiography revealed the presence of a cardiac tumor and her serum interleukin-6 level was elevated, we speculated she had a cardiac myxoma. Histological examination of the surgically resected specimen, however, revealed that the tumor was malignant fibrous histiocytoma. Although her disseminated intravascular coagulation and heart failure were transiently improved after operation, local recurrence and systemic metastasis occurred and she died 7 weeks after operation. Using the autopsied specimen, we examined whether the malignant fibrous histiocytoma constitutively synthesized interleukin-6. The interleukin-6 content in the tumor was high, consistent with interleukin-6 production by the tumor. This was confirmed by immunohistochemical analysis. To our knowledge, this is the first report demonstrating interleukin-6 production by a cardiac malignant fibrous histiocytoma.

Aged↗
PubMed1999

Total hip arthroplasty after failed intertrochanteric valgus osteotomy for advanced osteoarthrosis.

Thirty hips that had undergone conversion total hip arthroplasty because of failed intertrochanteric valgus osteotomy for advanced osteoarthrosis were analyzed clinically and radiographically for more than 2 years. The average followup after total hip arthroplasty was 7 years (range, 2-18 years). The average age of the patients at the time of valgus osteotomy was 42 years (range, 30-63 years). The average age of the patients at the time of conversion total hip arthroplasty was 57 years (range, 43-76 years), and the average period between valgus osteotomy and conversion was 14 years (range, 3-24 years). Perioperative complications in conversion total hip arthroplasties were minimal, and intramedullary reaming was performed easily. Of the 30 conversion total hip arthroplasties, 12 cemented and 18 cementless components were used, respectively. Kaplan-Meier's survival analysis indicated that survivorship of cemented stems was significantly higher than that of conventional cementless stems. Cemented stems are preferable for conversion total hip arthroplasty after failed femoral valgus osteotomy.

Adult↗
PubMed1999

Peroxisome proliferator-activated receptor gamma induces growth arrest and differentiation markers of human colon cancer cells.

Peroxisome proliferator-activated receptor gamma (PPAR gamma), one of the nuclear receptors expressed in adipose tissue, plays an important role in adipocyte differentiation. In this study, we investigated the expression of PPAR gamma and its role in cellular growth and differentiation in six colon cancer cell lines: HT-29, CaCo-2, SW-480, DLD-1, LoVo, and T-84. All six expressed PPAR gamma mRNA and protein, shown respectively on northern and western blot analyses. Luciferase assay in HT-29 cells, which strongly express PPAR gamma, showed that troglitazone, a selective ligand for PPAR gamma, transactivated the transcription of a peroxisome proliferator response element (PPRE)-driven promoter. Furthermore, troglitazone caused a marked decrease in [3H]thymidine incorporation and G1 cell-cycle arrest determined by flow cytometry. Finally, troglitazone induced expression of mRNAs for villin and intestinal alkaline phosphatase, markers for enterocyte differentiation. In conclusion, human colon cancer cells express PPAR gamma, the ligands of which inhibit cell growth and induce differentiation markers.

Calcium-Binding Proteins↗
PubMed1999

Cerebellar activation during ataxic gait in olivopontocerebellar atrophy: a PET study.

OBJECTIVE: To investigate the possible abnormal regional brain metabolism during ataxic gait in olivopontocerebellar atrophy (OPCA), and to evaluate the response of the cerebellar subregions to instability during bipedal gait. MATERIAL AND METHODS: On 9 patients with OPCA in early phase and on 10 age-matched normal subjects, we performed positron emission tomography (PET) with 2-[18F]fluoro-2-deoxy-D-glucose (FDG) under two different conditions: supine resting and 30 min treadmill walking. RESULTS: Both in normals and in patients with OPCA, the FDG uptake in the walking state (Uwalk) was significantly greater than that in the resting state (Urest) in the pyramis, declive-folium-tuber and culmen of the cerebellar vermis, and in the thalamus. In the patients, the Uwalk was also significantly greater than the Urest in the posterior lobe of cerebellar hemisphere and in the pons and midbrain. In the pyramis, the activation ratio (= Uwalk/Urest) of the patients was significantly lower than that of the normals. CONCLUSIONS: We considered that these findings reflect the pathophysiology of ataxic gait in OPCA patients and the compensatory mechanism for the instability during ataxic gait.

Adult↗