Search PubMed⌕ Search

Biomedical subjects

H Naito

Publications and source records attributed to H Naito.

At least 109 records · Page 6Linked to original sources
PubMed1998

Regional ventricular systolic abnormalities caused by a rudimentary chamber in patients with univentricular hearts.

Previous studies have demonstrated that regional wall motion abnormalities are common in univentricular hearts; however, the mechanism of this abnormality and its relation to hemodynamics remain unclear. The aim of this study was to document and analyze the etiology of regional wall motion abnormality and its relation to hemodynamics in univentricular hearts. Sixteen patients (age 11+/-6 years) were examined. A tagged cine magnetic resonance imaging method that superimposes "tags" on myocardium was used to assess regional systolic motion. The tags were traced from end-diastole to end-systole, and the percent regional shortening fraction was calculated as the shortening ratio. The tags were positioned on 6 segments. Normal ranges for wall motion were established from 10 normal volunteers. An asynchrony index was calculated as the SD divided by the mean regional shortening fraction to quantify asynchronous regional motion. Hemodynamic parameters were also obtained by cardiac catheterization. In patients, regional shortening fraction was significantly lower in segments adjacent to the rudimentary chamber compared with normal values in both circumferential and longitudinal directions (p <0.05 and p <0.01, respectively). The asynchrony index was much greater in patients than in controls (62+/-25 vs 27+/-10, p <0.01). The index correlated with rudimentary chamber volume and the rudimentary/main chamber volume ratio (r = 0.58, r = 0.79, respectively). Furthermore, the index correlated with end-diastolic pressure (r = 0.82). The rudimentary chamber may play an important role in causing asynchronous regional motion, and this motion may contribute to ventricular diastolic dysfunction.

Adolescent↗
PubMed1998

Hereditary dentatorubral-pallidoluysian atrophy: ubiquitinated filamentous inclusions in the cerebellar dentate nucleus neurons.

We examined the cerebellar dentate nucleus (CDN) in 16 patients with hereditary dentatorubral-pallidoluysian atrophy (DRPLA), one of the neurodegenerative diseases caused by expansion of a CAG repeat encoding a polyglutamine tract in the disease protein. In all patients, some CDN neurons were found to contain ubiquitinated filamentous inclusions in their cytoplasm. On hematoxylin and eosin preparations, these filamentous inclusions were eosinophilic, basophilic or amphophilic, and were often found in areas of pale cytoplasm. Electron microscopy revealed that they consisted of bundles of filaments that were somewhat thicker than neurofilaments. These features of the present inclusions were indistinguishable from those of skein-like inclusions (SLI) previously described in the lower motor neurons in sporadic amyotrophic lateral sclerosis. We conclude that SLI can also occur in the CDN in DRPLA and believe that they reflect a characteristic pathological process in this disease.

Adolescent↗
PubMed1998

Sodium butyrate-induced liver-type alkaline phosphatase activity in a small intestinal epithelial cell line, IEC6.

Sodium butyrate is a well-recognized differentiating agent inducing alkaline phosphatase activity, one of the epithelial differentiation markers. When IEC6 cells, a nontransformed, small intestinal epithelial cell line, were cultured with butyrate, this substrate induced alkaline phosphate activity in a time- and dose-dependent fashion. However, the type of isoenzyme involved was a liver-type, not an intestinal-type. Electron microscopy revealed that the induced activity was strictly localized in the cytosol and not on the plasma membrane. However, disaccharidase activities, another kind of differentiation marker, were also enhanced by sodium butyrate. In addition, the positive cells demonstrating the presence of alkaline phosphatase activity were preferentially observed in tubular structures. These data show that butyrate-induced alkaline phosphatase activity is closely associated with differentiation-like phenomena in IEC6 cells, although the type of isoenzyme and cellular localization of the activity are different from those observed in mucosa.

Alkaline Phosphatase↗
PubMed1998

Electroencephalogram abnormality and high-dose busulfan in conditioning regimens for stem cell transplantation.

High-dose busulfan (BU) is widely used in combined chemotherapy before allogeneic or autologous bone marrow transplantation. Convulsions are reported as a side-effect of high-dose BU. We recorded electroencephalograms (EEGs) before and on the third day of BU administration in 22 patients. Abnormal EEGs were observed on the third day in 13 cases (59%). These patients were older (P < 0.05) and had had larger doses of BU (P < 0.025) than the nine patients with normal EEGs. Convulsions occurred in two of the 22 patients, one of whom was receiving prophylaxis with phenytoin. Gamma aminobutyric acid (GABA), a natural mediator of defense against epileptic activity, concentrations in cerebrospinal fluid measured before and after administration of BU showed no definite changes.

Adolescent↗
PubMed1998

Dialysate pressure isobars in a hollow-fiber dialyzer determined from magnetic resonance imaging and numerical simulation of dialysate flow.

A procedure to determine dialysate pressure isobars by comparing the results of magnetic resonance imaging (MRI) and numerical simulation of the dialysate flow was established. The assumption used in the filtration analyses, that the dialysate pressure varies only in the central-axial direction, is supported by the finding that the determined isobars have no steep radial gradient. MRI of the contrast solution permeating the hollow fibers verifies the uniformity of the hollow fiber density in the dialyzer.

Algorithms↗
PubMed1998

Adsorption of complement, cytokines, and proteins by different dialysis membrane materials: evaluation by confocal laser scanning fluorescence microscopy.

The membranes tested in the present study were cellulose triacetate (CTA), polymethylmethacrylate (PMMA), and polyacrylonitrile (PAN). The adsorption by each membrane of albumin, IgG, C3a, interleukin-1beta (IL-1beta), interleukin-6 (IL-6), human neutrophil elastase (HNE), and tumor necrosis factor alpha (TNFalpha) was examined and semiquantitatively graded by confocal laser scanning fluorescence microscopy (CLSFM). After clinical use the dialyzers were treated with antibodies for these proteins and cytokines. Then the samples were incubated with fluorescein isothiocyanate-labeled anti-IgG antibody and observed by CLSFM. The changes in the blood levels of C3a and cytokines were also studied. In the CTA membrane, the adsorption of these substances, except for albumin and HNE, was less than in the synthetic membranes. The PAN membrane revealed the most abundant adsorption, especially for IL-1beta, IL-6, and TNFalpha. Although a marked elevation of C3a in the blood was observed in the CTA membrane, considerable adsorption was evident in the PMMA and the PAN membranes. Because the changes in the blood levels could be affected by membrane adsorption, both the blood levels and the adsorption of the biocompatibility parameters should be evaluated when membrane biocompatibility is discussed.

Acrylic Resins↗
PubMed1998

Amplification of int-2 and bcl-1 genes in squamous cell carcinoma of the larynx.

We studied int-2 and bcl-1 gene amplification in 21 operated patients with cancer of the larynx. In 9 cases, the int-2 gene was amplified (42.9%) and in 4 cases. the bcl-1 gene was amplified (25.0%). Co-amplification of int-2 and bcl-1 was observed in three cases (18.8%), all of which were glottic carcinomas. Other amplified cases were supraglottic carcinomas. Tumor specimens with int-2 amplification were associated with a significantly worse prognosis. We suggest that int-2 amplification is one of the prognostic factors in laryngectomized patients with cancer of the larynx.

Adult↗
PubMed1998

Exercise training reduces myocardial lipid peroxidation following short-term ischemia-reperfusion.

PURPOSE: The purpose of these experiments was to test the hypothesis that endurance exercise training will reduce myocardial lipid peroxidation following short-term ischemia and reperfusion (I-R). METHODS: Female Sprague-Dawley rats (4 months old) were randomly assigned to either a sedentary control group (N = 13) or to an exercise training group (N = 13). The exercise trained animals ran 4 d.wk-1 (90 min.d-1) at approximately 75% V02max. Following a 10-wk training program, animals were anesthetized, mechanically ventilated, and the chest was opened by thoracotomy. Coronary occlusion was achieved by a ligature around the left coronary artery; occlusion was maintained for 5 min followed by a 10-min period of reperfusion. RESULTS: Although training did not alter (P > 0.05) myocardial activities of antioxidant enzymes (superoxide dismutase and glutathione peroxidase), training was associated with significant increase (P > 0.05) in heat shock protein (HSP72) in the left ventricle. Compared with controls, trained animals exhibited significantly lower levels (P < 0.05) of myocardial lipid peroxidation following I-R. CONCLUSION: These data support the hypothesis that exercise training provides protection against myocardial lipid peroxidation induced by short-term I-R in vivo.

Animals↗
PubMed1998

Surgical aspect of enteroinsular axis after gastrointestinal surgery with reference to incretin secretion.

An alteration of the enteroinsular axis (EIA) may be an important etiologic factor in postsurgical changes in gastrointestinal (GI) function. In this review, we present recent works, both from our laboratory and others, on how changes in the EIA function may be involved in postsurgical GI complications, especially late dumping syndrome (LDS). We found no or minimal direct role for vagal signals in the control of gastric inhibitory polypeptide (GIP) and enteroglucagon secretion, which regulate EIA function. In gastrectomized patients, it is suggested that the hypersecretion of glicentin and glucagon-like peptide-1 (GLP-1) induced by a rapid arrival of nutrients to the distal gut suppresses glucagon secretion and may be a cause of LDS. In patients who underwent proctocolectomy, we observed no significant postoperative changes in EIA function, although there are some conflicting reports. It seems unlikely that ordinary pancreaticobiliary diversion would cause a significant change in EIA function after an oral glucose load. Our experimental model of ileojejunal transposition produced marked hypersecretion of incretin secreted from the distal gut, which may alter EIA function. Further elucidation of the regulatory mechanism of EIA may provide a new strategy for the medical and surgical treatment of LDS.

Digestive System Surgical Procedures↗
PubMed1998

A viewpoint determination system for stenosis diagnosis and quantification in coronary angiographic image acquisition.

This paper describes the usefulness of computer assistance in the acquisition of "good" images for stenosis diagnosis and quantification in coronary angiography. The system recommends the optimal viewpoints from which stenotic lesions can be observed clearly based on images obtained from initial viewpoints. First, the viewpoint dependency of the apparent severity of a stenotic lesion is experimentally analyzed using software phantoms in order to show the seriousness of the problem. The implementation of the viewpoint determination system is then described. The system provides good user-interactive tools for the semiautomated estimation of the orientation and diameter of stenotic segments and the three-dimensional (3-D) reconstruction of vessel structures. Using these tools, viewpoints that will not give rise to foreshortening and vessel overlap can be efficiently determined. Experiments using real coronary angiograms show the system to be capable of the reliable diagnosis and quantification of stenosis.

Coronary Angiography↗
PubMed1998

Exercise training improves myocardial tolerance to in vivo ischemia-reperfusion in the rat.

Experimental studies examining the effects of regular exercise on cardiac responses to ischemia and reperfusion (I/R) are limited. Therefore, these experiments examined the effects of endurance exercise training on myocardial biochemical and physiological responses during in vivo I/R. Female Sprague-Dawley rats (4 mo old) were randomly assigned to either a sedentary control group or to an exercise training group. After a 10-wk endurance exercise training program, animals were anesthetized and mechanically ventilated, and the chest was opened by thoracotomy. Coronary occlusion was achieved by a ligature around the left coronary artery; occlusion was maintained for 20 min, followed by a 10-min period of reperfusion. Compared with untrained, exercise-trained animals maintained higher (P < 0.05) peak systolic blood pressure throughout I/R. Training resulted in a significant (P < 0.05) increase in ventricular nonprotein thiols, heat shock protein (HSP) 72, and the activities of superoxide dismutase (SOD), phosphofructokinase (PFK), and lactate dehydrogenase. Furthermore, compared with untrained controls, left ventricles from trained animals exhibited lower levels (P < 0. 05) of lipid peroxidation after I/R. These data demonstrate that endurance exercise training improves myocardial contractile performance and reduces lipid peroxidation during I/R in the rat in vivo. It appears likely that the improvement in the myocardial responses to I/R was related to training-induced increases in nonprotein thiols, HSP72, and the activities of SOD and PFK in the myocardium.

Animals↗
PubMed1998

In vitro antitumor activities of new synthetic bistetrahydrofuran derivatives as analogs of Annonaceous acetogenins.

We investigated the in vitro antitumor activities toward mouse and human cell lines of optically active synthetic bistetrahydrofuran (bis-THF) derivatives as analogs of Annonaceous acetogenins, which contain bis-THF, long unbranched alkyl chains, hydroxyl groups, and an alpha, beta-unsaturated gamma-lactone. These bis-THF derivatives were synthesized in a stereocontrolled manner, and have several modified structures at the alkyl side chains. We found that: 1) the unsaturated gamma-lactone contributes to high potency in combination with the other less-functionalized alkyl chain, 2) the same absolute configuration of the bis-THF skeleton as that of the natural products produces more potent activity than the counterpart, 3) the alkyl chains and hydroxyl groups are crucial for exhibiting antitumor activity, 4) hydroxyl groups adjacent to the bis-THF skeleton may be replaced by amino or acylamino groups.

4-Butyrolactone↗
PubMed1998

Ontogenetic changes in responsiveness to benzodiazepine receptor ligands on ultrasonic vocalizations in rat pups.

The ontogenetic changes in responsiveness to benzodiazepine receptor ligands on ultrasonic vocalizations in rat pups from the age of day 3 to day 12 were evaluated. Rat pups, while separated from their dam and littermates and placed in a cold environment, emit ultrasonic vocalizations. These ultrasonic calls became attenuated dose-dependently in number and power after administration of the anxiolytic diazepam (0.25-1.0 mg/kg, s.c.), but the inhibitory effect of diazepam at the highest dose was less on day 6 and day 9. Moreover, type 1 benzodiazepine receptor ligands, Ro16-6028 and Ro23-0364 (0.5-2.0 mg/kg, s.c.), also dose-dependently attenuated the ultrasonic vocalizations 30-60 min after injection. The inhibitory effects of these drugs became more pronounced with the increasing age of the pup, and they were equivalent on day 12 to those in adult rats. These results suggest that different ontogenetic changes in development of two subtypes of central benzodiazepine receptors of pups might be related in the psychopharmacological mediation of the ultrasonic vocalization.

Animals↗
PubMed1998

Three-dimensional structure of mucosal and submucosal lymphatics in rat small intestine.

The organization of the lymphatic system in the rat ileum was investigated by the three-dimensional reconstruction using serial sections after dilatation of lymphatics. This method has an advantage to exclude possible artifacts in the conventional corrosion cast method. The villus possessed several lacteals and connected to each other by sinus. Two or three perpendicularly oriented lymphatics descended and led into the submucosal lymphatic network. In mucosa and submucosa, no valvular structure was detected. This study confirmed the voluminous lacteals and fine network structure of lymphatics in submucosa without valves, suggesting great potential to keep lymph and to drain soluble factors and cellular components.

Animals↗
PubMed1998

Three cases of the giant gastric leiomyosarcomas.

We report three cases of giant gastric leiomyosarcoma. Diagnosis was made prior to surgery using various diagnostic modalities. The patients were two women (77 and 77 years old) and one man (40 years old) whose chief complaints were abdominal pain, anorexia, and tarry stool. All patients presented with a large palpable mass in their upper abdomen at the time of admission. Based on characteristic findings from a gastric barium study, computed tomography (CT), and angiography, the patients were diagnosed as having gastric leiomyosarcomas displaying extramural growth. In the first case, a patient received a total gastrectomy, while local resection was performed in the second case because of pedunculated extragastric development. In the third case, total gastrectomy was combined with splenectomy and resection of the pancreatic tail. Twenty-two months after the original operation, the first case had multiple liver metastases. We present the three cases here, and review the literature.

Adult↗
PubMed1998

[The usefulness of fractal geometry for the diagnosis of small peripheral lung tumors].

PURPOSE: To assess the usefulness of fractal geometry in quantitatively evaluating the convergence of peripheral vessels on peripheral lung tumors in maximum intensity projection (MIP) images. MATERIALS AND METHODS: We studied the MIP images of 34 pathologically proved small peripheral lung tumors (lung cancer in 21, hamartoma in 13) in 34 patients. To obtain MIP images, spiral CT (SOMATOM PLUS; Siemens) was performed during a single breath hold (24-second scan time, 2-mm section thickness, and 2 mm/sec table feed time, reconstructed at 1-mm increments). To evaluate the convergence of the peripheral vessels and bronchi towards the tumor, we fixed a region of interest (ROI) on the hilar side of the lung tumor, parallel to the chest wall, which consisted of 64 x 64 square pixels, in the images that divided at the center of the window width. We counted the overlapping pixels by the two-dimensional box-counting method and obtained fractal dimensional data on lung cancers and hamartomas. RESULTS: There was a statistically significant difference in the fractal dimension (D) between lung cancers (D = 1.81 +/- 0.13) and hamartomas (D = 1.67 +/- 0.10) (P = 0.0067). CONCLUSION: Fractal geometry could be useful in the diagnosis of small peripheral lung tumors.

Diagnosis, Differential↗