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Biomedical subjects

S Kitamura

Publications and source records attributed to S Kitamura.

At least 469 records · Page 26Linked to original sources
PubMed1995

[Regional cerebral glucose metabolism associated with ataxic gait--an FDG-PET activation study in patients with olivopontocerebellar atrophy].

We studied changes in regional cerebral glucose metabolism during bipedal gait in 7 patients with olivopontocerebellar atrophy (OPCA) and 7 control subjects without neurological disease. All OPCA patients in this study were able to walk on the treadmill without a support or handrails. We used 18F-2-fluoro-2-deoxy-D-glucose (18F-FDG) and positron emission tomography (PET) to evaluate glucose metabolism under two different conditions; 30 minutes' treadmill walking, and supine resting. The two sets of PET images were three-dimensionally registered to the magnetic resonance image (MRI) in each subject. Then, the PET images were normalized by the global value. Regions of interest (ROIs) were drawn on the cerebellar vermis, cerebellar hemispheres, pons, and thalamus, and FDG uptake was obtained to calculate the activation ratio (= [FDG uptake under walking]/[FDG uptake under resting]) for each region. We used unpaired t-test for statistical analysis to compare the OPCA patients and the normal control subjects. Normalized resting FDG uptake had no significant difference between control subjects and OPCA patients in any region. Activation ratio of OPCA patients was significantly decreased in the cerebellar vermis compared with the control subjects. In the control subjects, FDG uptake had little difference between resting and walking in the cerebellar hemisphere, pons and thalamus. On the other hand, the FDG uptake of OPCA patients was moderately increased by walking in these regions. In the cerebellar vermis, in spite of no significant difference between the normals and the patients during resting, the activation ratio in OPCA patients was significantly decreased. We speculate that the reduction of activation ratio in the cerebellar vermis reflects the dysfunction caused by degeneration. The result suggests that the PET activation study can demonstrate cerebellar dysfunction in the early phase of OPCA, in which other neuro-imaging methods cannot detect the tissue atrophy, hypometabolism or hypoperfusion in the resting state. In the cerebellar hemisphere, pons and thalamus, the activation ratio was nearly equal to one in control subjects, while it was larger in OPCA patients. We speculate that the instability during the ataxic gait increases the inputs from the vestibular, somatosensory and visual systems to these regions and outputs from these regions to the other neural systems. In conclusion, PET activation study is a useful and noninvasive technique for investigating the brain function associated with human gait.

Adult↗
PubMed1995

[Cerebello-cerebral functional relationship in spinocerebellar degeneration using positron emission tomography].

In order to investigate the laterality of cerebellar ataxia and its influence for the cerebral cortex in spinocerebellar degeneration (SCD), regional cerebral blood flow (r CBF) was measured using positron emission tomography (PET) in 10 patients with sporadic olivopontocerebellar atrophy (sOPCA), 7 patients with hereditary SCD (h SCD), and 10 age matched control subjects. The laterality of cerebellar ataxia was evaluated by the total score of the difference between left and right limbs of three limb-coordination tests. The lateralities of rCBF were calculated by asymmetry indices (AIs) of each region of interest in the cerebellum, thalamus, caudate, putamen, cerebral cortices. The laterality of cerebellar ataxia was significantly correlated with AI in the cerebellum in patients with sOPCA. Furthermore, significant negative correlations were observed between AI in the cerebellum and each AI in the thalamus, frontal cortex in patients with sOPCA. However, no correlations were observed between AI in the cerebellum and the other AIs in controls and patients with h SCD. Duration of illness in patients with sOPCA with laterality is shorter than that in patients without laterality. These results suggest that the existence of crossed cerebello-cerebral diaschisis (CCCD) resulting from transneuronal deactivation through cerebello-thalamo-cerebral pathway in patients with the early stage of sOPCA with laterality.

Adult↗
PubMed1994

An antitumor, branched (1-->3)-beta-D-glucan from a water extract of fruiting bodies of Cryptoporus volvatus.

A water-soluble, (1-->6)-branched (1-->3)-beta-D-glucan (H-3-B) was isolated from a hot-water extract of the fruiting bodies of the fungus, Cryptoporus volvatus (Basidiomycetes). Enzymatic analysis using exo-(1-->3)-beta-D-glucanase and methylation analysis indicated that this polysaccharide has a main chain composed of beta-(1-->3)-linked D-glucopyranosyl residues, and single, beta-(1-->6)-linked D-glucopyranosyl residues attached as side chains to, on average, every fourth sugar residue of the main chain. This structure was confirmed by 13C NMR spectra of the glucan in Me2SO-d6. The weight-average molecular weight (Mw) of H-3-B was determined to be 44.0 x 10(4) by gel permeation chromatography equipped with a low-angle laser-light-scattering photometer. The electron microscopic observations showed that H-3-B and its sonicated sample (S-H-3-B, Mw = 13.7 x 10(4)) can be described as linear worm-like chains. The mass per unit length for native and sonicated H-3-B was determined to be 1750 and 1780 g mol-1 nm-1, respectively, from the contour lengths obtained by electron microscopy and the molecular weights. These values are in good agreement with that expected for the triple stranded structure. A sample denatured in 0.1 M NaOH and subsequently renatured by neutralization showed a mixture of linear and cyclic structures, and larger aggregates with less well-defined morphology. The H-3-B and S-H-3-B had antitumor activity against the Sarcoma 180 tumor.

Animals↗
PubMed1994

Distribution of motoneurons supplying dorsal and ventral suboccipital muscles in the feline neck.

A combination of retrograde tracers was used to compare the relative distributions of motoneurons supplying the ventral and lateral suboccipital muscles, rectus capitis anterior (RCA), and rectus capitis lateralis (RCL), with those supplying dorsal muscles, including rectus capitis posterior muscles (RCP), complexus (CM), and the medial head of obliquus capitis superior (OCS). Three of the tracers, horseradish peroxidase, fluororuby, and fluorescein-conjugated dextran, were applied to cut nerve ends. Fast blue was applied by intramuscular injection, and fluorogold was delivered both by injection and by cut nerve exposure. Motoneurons supplying RCA and RCL were clustered on the medial wall of the ventral horn in a restricted region defined previously as the commissural nucleus. Labelled cells supplying RCL were confined to the C1 segment, but those supplying RCA were distributed from C1 to rostral C4. Motoneurons supplying RCA tended to lie more dorsomedially than those supplying RCL, but there was substantial overlap between the two populations. Motoneurons supplying dorsal muscles had a separate, more ventral distribution. RCP motoneurons were located primarily in the ventromedial nucleus, but a small proportion of cells was found in the white matter of the ventral funiculus or the gray matter surrounding the central canal. Motoneurons supplying CM and OCS were located dorsomedially to the RCP cell population. These results suggest that neck motoneurons are arranged according to a "musculotopic" pattern in which dorsal muscles have the most ventral locations, and progressively more lateral and then ventral muscles are layered dorsomedially along the medial wall of the ventral horn.

Animals↗
PubMed1994

Molecular and crystal structure of (2,3,4,6-tetra-O-acetyl-beta-D-glucopyranosyl)-(1-->3)- [2,3,4,6-tetra-O-acetyl-beta-D-glucopyranosyl-(1-->6)]- (2,4-di-O-acetyl-beta-D-glucopyranosyl)- (1-->3)-1,2,4,6-tetra-O-acetyl-beta-D-glucopyranose.

Crystals of the tetrasaccharide, (2,3,4,6-tetra-O-acetyl-beta-D-glucopyranosyl)-(1-->3)- [2,3,4,6-tetra-O-acetyl-beta-D-glucopyranosyl-(1-->6)]- (2,4-di-O-acetyl-beta-D-glucopyranosyl)-(1-->3)- 1,2,4,6-tetra-O-acetyl-beta-D-glucopyranose, belong to the monoclinic system, space group P2(1), with a = 12.709(4), b = 27.767(9), c = 9.567(4) A, beta = 105.07(2) degrees, and Z = 2. The crystal structure was solved by the direct method and refined by the full-matrix least-squares procedure to an R-value of 0.071 for 302- observed reflections in the X-ray data. All the four D-glucopyranose residues have the usual 4C1 chair conformations. The torsional angles at two (1-->3)-beta-linkages were phi(O-5-1-O-1-C-3) = -74 degrees and psi (C-1-O-1-C-3-C-2) = -122 degrees between the nonreducing and the middle residues, and phi = -67 degrees, psi = -111 degrees between the middle and the reducing residues. The orientation about the (1-->6)-beta-linkage was found to be phi(O5-C1-O-1-C-6) = -77 degrees, theta(C1-O-1-C-6-C-5) = 160 degrees, and chi(O-1-C-6-C-5-O-5) = 63 degrees (gt conformation). The primary acetate groups at C-6 of the reducing and the (1-->6)-branched residues were in the gt conformations (O-5-C-5-C-6-O-6 = 81 degrees and 84 degrees, respectively). On the other hand, the gg conformation was observed for the primary acetate group in the nonreducing residue (O-5-C-5-C-6-O-6 = 78 degrees).

Carbohydrate Conformation↗
PubMed1994

Multicystic aneurysmal dilatation of bilateral coronary artery fistula.

Bilateral coronary artery fistula constitutes an uncommon subgroup of coronary artery fistulas that may have a distinct embryologic origin. Coronary artery fistulas usually show a tortuous arrangement upon coronary angiography, but aneurysmal dilatation is rare. We report here an extremely rare case of coronary artery fistula originating from both coronary arteries, which showed multicystic aneurysmal dilatation.

Aged↗
PubMed1994

Percutaneous transluminal coronary angioplasty of the left internal thoracic artery graft: a case report in a child.

A 9-year-old girl who had undergone previous coronary artery bypass surgery at the age of 3.5 years for stenoses of the left anterior descending and right coronary arteries resulting from Kawasaki disease presented with recurrent exertional angina. Stenosis was found at the anastomosis of the left internal thoracic artery to the left anterior descending artery. Percutaneous transluminal coronary angioplasty was successfully performed. This is the first reported case of percutaneous transluminal coronary angioplasty of an internal thoracic artery graft in a child.

Angioplasty, Balloon, Coronary↗
PubMed1994

Salmon gonadotropin-releasing hormone and gonadotropin are involved in precocious maturation induced by photoperiod manipulation in underyearling male masu salmon, Oncorhynchus masou.

The relationship between gonadal maturation, salmon gonadotropin-releasing hormone (sGnRH), and gonadotropin (GTH) subunit contents in the brain and pituitary was investigated in underyearling masu salmon, Oncorhynchus masou. Gonadal maturation was manipulated by changing photoperiod to examine the involvement of these hormones in this process. Fish were divided into short (8 hr L: 16 hr D) and long photoperiod (16 hr L:8 hr D) groups in mid-June and maintained for 4 months until October. Gonadal maturation occurred in most males (precocious males), while a few remaining males and all females did not mature throughout the experiment irrespective of photoperiodic group. In precocious males, pituitary contents of sGnRH, GTH I beta, and GTH II beta increased faster under short photoperiod than under long photoperiod, and spermiation was observed in August. Under long photoperiod, these hormones gradually increased until October when spermiation occurred. sGnRH concentrations in the telencephalon of precocious males were high when spermiation occurred; in August, they were higher in the short photoperiod than in the long photoperiod group; in October, they were higher in the long photoperiod group. The increases of sGnRH and GTH in the pituitary and sGnRH in the brain appear to be involved in precocious maturation inducible by manipulation of photoperiod.

Animals↗
PubMed1994

Activation of salmon gonadotropin-releasing hormone synthesis by 17 alpha-methyltestosterone administration in yearling masu salmon, Oncorhynchus masou.

Juvenile salmonid pituitary gonadotropin (GTH) contents are elevated after steroid hormone treatment, but the involvement of gonadotropin-releasing hormone (GnRH) is unclear. Activation of salmon GnRH (sGnRH) synthesis by 17 alpha-methyltestosterone (MT) administration has been examined in the brain of yearling masu salmon (future precocious males and immature females) using an in situ hybridization technique combined with radioimmunoassay. Oral MT application markedly increased pituitary GTH II beta, but not GTH I beta, contents in both sexes. In future precocious males, MT treatment increased the number of cells expressing sGnRH mRNA in the preoptic area about threefold, whereas there were no significant differences in the olfactory bulbs and the ventral telencephalon. No significant changes were observed in cell sizes nor the numbers of silver grain per 100 microns2 cell in any of the brain regions. Thus, in future precocious males, preoptic sGnRH neurons may be activated by sex steroids. In contrast, no significant changes were observed in sGnRH mRNA levels of immature females after MT treatment. These differences in responses to sex steroids of sGnRH cells in the preoptic area between future precocious males and immature females suggest that MT has indirect actions via sGnRH and/or direct actions on the pituitary in the former, and that MT acts directly on the pituitary in the latter.

Animals↗
PubMed1994

Conformation of (2-->1)-beta-D-fructan in aqueous solution.

The conformation and dilute solution properties of (2-->1)-beta-D-fructan in aqueous solution were studied by gel permeation chromatography, low-angle laser light-scattering photometry, viscometry, small-angle X-ray scattering and electron microscopy. Fractions covering a broad range of weight-average molecular weights (Mw) from 1.49 x 10(4) to 5.29 x 10(6) were obtained from a native sample by ultrasonic degradation and fractional precipitation. For Mw < 4 x 10(4), the intrinsic viscosity [eta] varies with Mw0.71, indicating that the fructan chain behaves as a random coil expanded by an excluded-volume effect in this molecular weight region. For Mw > 10(5), [eta] exhibits an unusually weak dependence on Mw and finally becomes almost independent of molecular weight. This behaviour is interpreted in terms of a globular conformation of the high-molecular-weight fructan molecules. Small-angle X-ray-scattering measurements and electron microscopic observations support this interpretation of the values of [eta] observed.

Aspergillus↗
PubMed1994

Efficacy of seven retrograde tracers, compared in multiple-labelling studies of feline motoneurones.

The labelling efficacies of 7 retrograde tracers were evaluated following cut nerve exposure or intramuscular injection into the serially compartmentalized neck muscle, biventer cervicis. Tested tracers included Fast Blue (FB), Fluorogold (FG), dextran conjugated to fluorescein (FD), dextran conjugated to rhodamine (Fluororuby (FR), 3000 and 10,000 MW), fluorescent latex microspheres, horseradish peroxidase coupled to colloidal gold, and 1,1'-dioctadecyl-3,3,3',3'-tetramethyl indocarbocyanine perchlorate (DiI). In 2 animals, horseradish peroxidase was also employed and spinal cords were processed for peroxidase activity to evaluate its effect on the appearance of cells labelled with fluorescent tracers. Four tracers, FB, FG, FD and FR, could be observed in motoneurones under the conditions of our study. FB and FG labelled comparable numbers of motoneurones following cut nerve exposure, but dissimilar numbers following intramuscular injection. FG diffused extensively following injection and was found in motoneurones not only in the appropriate ipsilateral segment but also adjacent ipsilateral and contralateral segments. Intramuscular injections of FB usually labelled fewer cells than cut nerve exposure, but evidence for spurious labelling following intramuscular injection could also be found. FD or FR labelled motoneurones following cut nerve exposure but not following intramuscular injection. The conjugated dextrans labelled more variable numbers of cells than FB or FG, but the labelled cells had similar patterns of distribution. The remaining tracers were ineffective as retrograde markers in our study, and the possible reasons for these failures are discussed.

Amidines↗
PubMed1994

Diet therapy and food exchange lists for diabetic patients.

The present situation of diet therapy for diabetes in Japan is described in this chapter. The diabetic diet in Japan is based on Japanese traditional food and eating habits. So far, it has effectively contributed to the treatment of diabetes. The aim of diet therapy for the diabetic regimen in Japan is, as in other countries, firstly, to supply energy for maintaining adequate body weight and healthy social activities, and secondly, to attain glycemic control as close as possible to that of a non-diabetic person to prevent the occurrence of diabetic complications. The Japan Diabetes Society has elucidated the following principles of diet therapy for the accomplishment of the above purposes. (1) The proper amount of daily energy intake means the amount which affords physical activities. (2) The proportion of the 3 main nutrients should be: 60% as carbohydrate, 15-20% protein and 20-25% fat. (3) As to vitamins and minerals, an appropriate amount to meet the average requirement should be supplied daily. (4) It is recommended that a proper amount of fiber be taken. Furthermore, with regard to patient education, which is the most important aspect of adhering to diet therapy, an outline of the latest (1993) edition of the 'Food Exchange Lists', having been first edited in 1965 by the Japan Diabetes Society, is introduced together with its use.

Diabetes Mellitus↗
PubMed1994

Effects of nicotine on production of endothelin and eicosanoid by bovine pulmonary artery endothelial cells.

To clarify the relationship between cigarette smoking and regulators of vascular tone derived from endothelium, the authors studied the acute and subacute effects of nicotine on endothelin and eicosanoid production by bovine pulmonary artery endothelial cells (BPAEC). The acute effects of nicotine were assessed by measuring the release of endothelin, prostaglandin I2 (PGI2), and thromboxane A2 (TXA2) from BPAEC after their incubation with a medium containing various concentrations of nicotine (10(-9) M - 10(-3) M) for 24 h. The subacute effects were assessed after 1 week's culture of BPAEC in the presence of nicotine (10(-7) M, 10(-3) M). Acute exposure to a high concentration of nicotine (10(-5) M - 10(-3) M) led to a significant inhibition of endothelin production by BPAEC. Nicotine, 10(-3) M, inhibited PGI2 production, but led to release of lactate dehydrogenase. Subacute exposure to nicotine (10(-3) M) also inhibited the production of endothelin and PGI2 by BPEAC. A high concentration of nicotine reduced the production of endothelin and PGI2 by BPAEC, probably due to the cytotoxicity of nicotine. Concentrations of nicotine comparable to the plasma levels of nicotine found in smokers (10(-9) - 10(-6) M) did not affect the release of endothelin and PGI2 from BPAEC. The mechanism of nicotine-induced vasoconstriction may be independent of the release of endothelin or PG derivatives from endothelial cells.

6-Ketoprostaglandin F1 alpha↗
PubMed1994

Epoxide reductase activity of mammalian liver cytosols and aldehyde oxidase.

The present study provides the first evidence that a mammalian liver cytosolic enzyme, aldehyde oxidase, has an ability to reduce arene oxides to the parent hydrocarbons under anaerobic conditions. The comparative ability of rabbit liver preparations to reduce arene oxides was examined using naphthalene 1,2-oxide and benzo[a]pyrene 4,5-oxide as substrates. The liver cytosol with an electron donor of aldehyde oxidase exhibited much higher epoxide reductase activity compared with the liver microsomes with NADPH and FAD. The cytosolic activity was sensitive to inhibitors of aldehyde oxidase. Purified rabbit liver aldehyde oxidase also exhibited a significant epoxide reductase activity in the presence of its electron donor. Apparent Km and Vmax values of the enzyme were 426 microM and 323 nmol/min/mg protein for naphthalene 1,2-oxide and 255 microM and 100 nmol/min/mg protein for benzo[a]pyrene 4,5-oxide respectively. However, no epoxide reduction by the enzyme or by the liver cytosol was detected in olefin epoxides such as styrene oxide and trans-stilbene oxide. Similar results were obtained with rat liver preparations. However, the epoxide reductase activity of cytosol and aldehyde oxidase from rat liver was considerably lower than that of the rabbit liver preparations. In hamsters, mice and guinea-pigs, liver cytosols with an electron donor of aldehyde oxidase as well as liver microsomes with NADPH exhibited a significant epoxide reductase activity toward naphthalene 1,2-oxide. However, no epoxide reduction was observed with dog liver cytosol. Administration of sodium tungstate to rats depleted liver cytosolic reductase activity and sodium molybdate treatment resulted in partial restoration of the activity, supporting the view that the epoxide reductase activity observed in the liver cytosol mainly originates from aldehyde oxidase.

Aldehyde Oxidase↗
PubMed1994

Clinical usefulness of CYFRA assay in diagnosing lung cancer: measurement of serum cytokeratin fragment.

We evaluated the diagnostic usefulness of measurement of the soluble cytokeratin 19 fragment, a new tumor marker, in 391 patients with lung cancer and in 424 patients with benign lung diseases. Serum concentrations of cytokeratin 19 fragment were measured by a sandwich ELISA (CYFRA). The cut-off value was defined as 3.5 ng/ml, which is associated with a specificity of 85% for benign lung diseases. CYFRA had a high sensitivity (57.5%) in all subjects with lung carcinoma, and had a higher sensitivity for squamous cell carcinoma (73.1%, n = 141) than squamous cell carcinoma-related antigen (61.0%). CYFRA was associated with a relatively high sensitivity (42.1%) in early-stage squamous cell carcinoma (stage I, based on the classification of the Japan Lung Cancer Society), but the CYFRA titer was higher in advanced squamous cell carcinoma than in early-stage squamous cell carcinoma. Our findings suggest that CYFRA is potentially useful for diagnosis and monitoring of lung carcinoma, especially for squamous cell carcinoma.

Biomarkers, Tumor↗
PubMed1994

[A case of Corynebacterium jeikeium septicemia].

We report a case of Corynebacterium jeikeium septicemia associated with malignant lymphoma. The patient is a 58-year-old male who was diagnosed as malignant lymphoma on August 1992. May 15, 1993, he was admitted to our hospital because of oliguria, abdominal flatulence and vomiting which developed a few days before admission. Anticancer regimen were started. In the middle of July, white blood cell (WBC) count dropped to 100/mm3 and body temperature rose to 39 degrees C. He was been treated with Ceftazidime and Piperacillin. C. jeikeium was recovered from blood culture. Antibiotics were switched to minocycline and vancomycin. He died of septic shock and pneumonia. Autopsy revealed the presence of the colonies of Rods. Which were morphologically compatible with C. jeikeium were observed in lung tissue and in the small pulmonary vessels.

Bacteremia↗
PubMed1994

Chronic hyperinsulinemia augments deoxycorticosterone acetate-salt hypertension.

To evaluate the effect of chronic hyperinsulinemia on blood pressure in salt-dependent hypertension, we infused insulin (1.0 IU/d, n = 15) or saline (n = 13) for 4 weeks into deoxycorticosterone acetate-salt hypertensive rats. The insulin infusion increased plasma insulin levels to 24 +/- 2 microU/mL, which was higher than in the saline-infused rats (9 +/- 1 microU/mL) but was still within the physiological range. Blood pressure was measured by the tail-cuff method twice a week, and daily sodium intake and urinary sodium excretion were calculated for 3 weeks. At week 4, arterial pressor responsiveness to norepinephrine, angiotensin II, and hexamethonium bromide was evaluated. After 14 days of chronic infusion, the insulin group showed a higher blood pressure than the saline group (on 21st day: 178 +/- 6 versus 156 +/- 5 mm Hg, P < .05 by tail-cuff method; 171 +/- 4 versus 149 +/- 3 mm Hg, P < .05 by direct intra-arterial measurement). This blood pressure difference was eliminated after ganglionic blockade with hexamethonium bromide (86 +/- 4 mm Hg in insulin-treated and 89 +/- 4 mm Hg in saline-treated rats by direct intra-arterial measurement). Throughout the experiment, neither sodium balance nor arterial pressor responsiveness to norepinephrine or angiotensin II differed between the two groups. In conclusion, chronic hyperinsulinemia in the physiological range augments the development of hypertension in salt-dependent hypertension, and this augmentation may be mediated by sympathetic stimulation independent of salt retention.

Analysis of Variance↗