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Biomedical subjects

M Nasu

Publications and source records attributed to M Nasu.

At least 145 records · Page 8Linked to original sources
PubMed1998

[Determinants of long-term outcome for operative survivors of acute aortic dissection].

Predictability of aorta-related complications and survival was examined in 79 operative survivors of acute aortic dissection. Follow-up was 94.9% complete and totaled 458 patient-years. Actuarial survival was 93 +/- 3% (+/- S.E.) (n = 43) at 5 years, and 74 +/- 8% (n = 13) at 10 years. Survival was significantly lower in patients having neurological complication. Freedom from aorta-related complications was 82 +/- 5% (n = 37) at 5 years, and 67 +/- 8% (n = 11) at 10 years. Multivariate Cox regression analysis identified residual entry and leak on anastomotic site as independent predictors of aorta-related complications. We conclude that in the treatment of acute aortic dissections, reducing the incidence of residual entry and leak on anastomotic site improves long-term outcome.

Acute Disease↗
PubMed1998

[Assessment of enlarged left atrium with 99mTc-tetrofosmin SPECT and echocardiography].

This study was performed to clarify the possibility of visualization and quantification with 99mTc-tetrofosmin (Tf) myocardial scintigraphy in cases with a large atrium demonstrated by trans-thoracic echocardiography (TTE). Myocardial SPECT was evaluated in 4 patients with mitral stenosis and 15 patients with mitral regurgitation. Left atrium was identified in 12 out of 19 cases from an antero-posterior projection. The Tf uptake ratio of the left atrium, which was defined as the ratio of ROI count of the left atrium divided by the ROI count of the left ventricle, showed a good correlation with the left atrial area obtained by both trans-thoracic and trans-esophageal echocardiography (r = 0.88 and 0.91, respectively), These data suggest that Tf myocardial SPECT is a useful method of evaluating left atrial enlargement.

Aged↗
PubMed1998

[Pulmonary dirofilariasis associated with pleural effusion].

A 61-year-old man was admitted to our hospital because of a long history of productive coughing. A chest roentgenogram and CT scan showed a right-sided pleural effusion. The effusion fluid was blood-stained but showed no cytological evidence of malignancy. Marked eosinophilia was found in blood and in the pleural effusion fluid. Ouchterlony's double-diffusion test done with the patients serum and pleural effusion fluid in agarose showed specific bands toward Dirofilaria immitis antigen, and this specificity was confirmed with an enzyme linked immunosorbent assay inhibition test. The final diagnosis was pulmonary dirofilariasis, and the patient responded to diethylcarbamazine.

Animals↗
PubMed1998

Comparison of PCR, (1-->3)-beta-D-glucan and galactomannan assays in sera of rats with experimental invasive aspergillosis.

We compared PCR, galactomannan detection assay using a latex agglutination test and (1-->3)-beta-D-glucan detection assay in detecting infection in rats experimentally infected with Aspergillus fumigatus. On day 2 after inoculation, (1-->3)-beta-D-glucan and nested PCR were positive for 80%, while galactomannan detection assay was positive for 60%. In addition, the positive result of nested PCR (87.5%) was higher than those of galactomannan detection assay (75%) and (1-->3)-beta-D-glucan (71.4%) on day 3 after inoculation. The sensitivity of nested PCR was superior to those of galactomannan detection assay and (1-->3)-beta-D-glucan detection assay. The three diagnostic tests were compared with histopathological findings, and the sensitivity of three diagnostic tests was correlated with histopathological changes. In addition, the elevated levels of (1-->3)-beta-D-glucan paralleled the development and progression of pulmonary aspergillosis. Our results indicate that a combination of two or three of these tests seems to provide a rapid diagnosis of invasive aspergillosis and assist in the evaluation of the development and severity of invasive aspergillosis.

Animals↗
PubMed1998

Toxigenicity of Helicobacter pylori isolates possessing cagA gene and vacuolating cytotoxin.

Inflammatory cells in the gastric epithelium and direct cell damage are important effects of H. pylori infection in causing gastroduodenal diseases. The aim of this study was to determine whether H. Pylori possessing the cagA gene and vacuolating cytotoxin activity (cagA+/tox+) has these toxigenicities. The detection of cagA was performed by the polymerase chain reaction method. Culture supernatants of H. pylori were tested on rabbit gastric epithelial cell culture for intracellular vacuolation. H. pylori isolates were divided into two major types, cagA+/tox+ and cagA-/tox- strains. Ten Japanese monkeys were allocated to two groups, with six animals inoculated with the cagA+/tox+ strain and four animals inoculated with the cagA-/tox- strain. Five other Japanese monkeys served as controls. They were observed endoscopically every week and the severity of gastritis was evaluated in biopsy specimens obtained from the antral mucosa. Histopathological examination of the gastric mucosa revealed a more severe neutrophil infiltration caused by the cagA+/tox+ strain than that caused by the cagA-/tox- strain for 3 months after inoculation. These findings indicate that cagA and vacuolating cytotoxin may be important factors in causing the severe damage of the human gastric mucosa produced by H. pylori.

Animals↗
PubMed1997

Optical imaging of dynamic horizontal spread of excitation in rat auditory cortex slices.

Optical recordings using a voltage-sensitive dye (RH482) were conducted in brain slice preparations to investigate spatiotemporal patterns of excitation in the rat auditory cortex. Electrical stimulation of the border between the white matter and layer VI evoked vertical as well as horizontal spreading responses. While velocities of vertical and horizontal propagation of excitation were similar to those reported in non-disinhibited preparations, the horizontal propagation was widespread and strong especially in layers II/III in auditory cortex slices. This horizontal spread was blocked by 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) but not by D-2-amino-5-phosphonopentanoic acid (D-AP5). These results suggest that the horizontal responses, especially in layers II/III, are prominent and are mediated primarily by non-N-methyl-D-aspartic acid (NMDA) receptors in the auditory cortex.

2-Amino-5-phosphonovalerate↗
PubMed1997

Stimulatory effects of parathyroid hormone and 1,25-dihydroxyvitamin D3 on insulin-like growth factor-binding protein-5 mRNA expression in osteoblastic UMR-106 cells: the difference between transient and continuous treatments.

The transient treatment with parathyroid hormone (PTH) for 12 h, followed by its removal for 36 h, stimulated insulin-like growth factor-binding protein (IGFBP)-5 mRNA expression more strongly than the continuous treatment for 48 h in osteoblastic UMR-106 cells. The transient but not continuous treatment with A23187 also stimulated it. In contrast, 1,25-dihydroxyvitamin D3 stimulated it, irrespective of the treatment design. IGFBP-5 stimulated type-1 procollagen mRNA expression. The present study first indicated that the transient treatment with PTH more effectively stimulated IGFBP-5 mRNA expression than its continuous treatment partly via an increase in intracellular calcium and suggested that IGFBP-5 might be involved in the anabolic action of PTH in bone.

Animals↗
PubMed1997

Effect of pravastatin (10 mg/day) on progression of coronary atherosclerosis in patients with serum total cholesterol levels from 160 to 220 mg/dl and angiographically documented coronary artery disease. Coronary Artery Regression Study (CARS) Group.

To evaluate the effect of pravastatin on progression of coronary atherosclerosis in normocholesterolemic patients with coronary artery disease (CAD), 90 patients with CAD and serum cholesterol levels of 160 to 220 mg/dl were randomized into a pravastatin (10 mg/day) group (n = 45) and control group (n = 45) in a 2-year study. The proportions of patients with progression (an increase of > or = 15% in percent stenosis) and regression (a decrease of > or = 15% in percent stenosis) of coronary atherosclerosis were compared between the 2 groups. Of 90 patients, 80 (89%) had a final angiogram: the pravastatin (n = 39) and control group (n = 41). Percent changes in total cholesterol, low-density lipoprotein cholesterol, and apoprotein B levels were significantly greater in the pravastatin group than in the control group (total cholesterol -11 +/- 12% vs 3 +/- 15%, p < 0.01; low-density lipoprotein cholesterol -18 +/- 16% vs 4 +/- 21%, p < 0.01; apoprotein B -5 +/- 20% vs 6 +/- 20%, p < 0.05). The proportion of patients with progression of coronary atherosclerosis was significantly smaller in the pravastatin group than in the control group (21% vs 49%, p < 0.05). The proportion of patients with disease regression did not differ in the 2 groups (3% vs 2%, p = NS). In conclusion, this study indicates that cholesterol-lowering therapy with pravastatin can prevent the progression of coronary atherosclerosis even in normocholesterolemic patients with established CAD.

Anticholesteremic Agents↗
PubMed1997

Significance of negative U waves in the precordial leads during anterior wall acute myocardial infarction.

This study was conducted to clarify the clinical significance of negative U waves in the precordial leads during anterior wall acute myocardial infarction (AMI). In all, 141 patients with first anterior wall AMI (< or = 6 hours) were classified into 2 groups according to the presence (group A, n = 31) or absence (group B, n = 110) of negative U waves in the precordial leads on the admission electrocardiogram (ECG). The number of leads showing ST elevation > or = 1 mm on the admission ECG was smaller in group A than in group B (5.2 +/- 1.3 vs 6.2 +/- 1.7, p < 0.01). Emergent coronary arteriography revealed that group A had a higher incidence of good collateral circulation than group B (39% vs 19%, p < 0.05). Peak creatine kinase activity was lower in group A than in group B (1,708 +/- 1,271 vs 2,735 +/- 1,865 IU/L, p < 0.01). The number of abnormal Q waves on the predischarge ECG was smaller in group A (2.0 +/- 1.5 vs 3.4 +/- 2.0, p < 0.01). Group A had a greater left ventricular ejection fraction and better regional wall motion in the anterobasal, anterolateral, and apical regions in the chronic phase than group B. In conclusion, patients with anterior wall AMI having negative U waves in the precordial leads on admission had a relatively smaller mass of necrotic myocardium than those without the waves. Therefore, negative U waves during anterior wall AMI may be a useful marker for identifying patients with smaller infarction partly due to better collateral circulation.

Angioplasty, Balloon, Coronary↗
PubMed1997

Behçet's disease associated with myelodysplastic syndromes. A case report and a review of the literature.

BACKGROUND: Behçet's disease has rarely been reported in association with myelodysplastic syndromes (MDS). Increased production of reactive oxygen species (ROS) by neutrophils has a primary role in the pathogenesis of Behçet's disease. However, decreased production of ROS by neutrophils has frequently been reported in patients with MDS. The current study was undertaken to determine the role of ROS production in a patient with Behçet's disease and MDS. METHODS: A patient with MDS with trisomy 8 who developed Behçet's disease is described and a review of the literature of patients with Behçet's disease in MDS is presented. The production of ROS by neutrophils was investigated by luminol-enhanced chemiluminescence (CL) assay. RESULTS: Based on a review of the literature, 10 cases of Behçet's disease associated with MDS have been reported to date. Nine patients had undergone cytogenetic analysis of bone marrow cells, 7 of whom (78%) had trisomy 8. Neutrophils taken from the authors' patient during the active phase of Behçet's disease demonstrated an increased CL response. Moreover, serum from this patient increased the CL emission of neutrophils from healthy volunteers. CONCLUSIONS: These data suggest that trisomy 8 predisposes to Behçet's disease in patients with MDS. Furthermore, an increased ROS production by neutrophils may be associated with the diverse clinical findings in this disease. In this study, neutrophils were activated directly by serum factors.

Adult↗
PubMed1997

Insulin-like growth factor-I mediates osteoclast-like cell formation stimulated by parathyroid hormone.

There have been several lines of evidence that parathyroid hormone (PTH) stimulates production of insulinlike growth factor I (IGF-I) in bone and that IGF-I stimulates osteoclast formation. Thus, the present study was performed to clarify the possible role of IGF-I in PTH-stimulated osteoclastlike cell formation and the role of PTH-responsive dual signal transduction systems (cyclic [c] AMP-dependent protein kinase [PKA] and calcium/protein kinase C [PKC]) in its mechanism. Treatment with anti-IGF-I antibody (1-10 micrograms/ml) partially but significantly blocked hPTH-(1-34)-stimulated osteoclastlike cell formation in unfractionated mouse bone cell cultures, although it did not affect osteoclastlike cell formation stimulated by 1,25-dihydroxyvitamin D3. Rp-cAMP5 (10(-4) M), a direct PKA inhibitor, as well as two types of PKC inhibitors, H-7 (10 microM) and staurosporine (3 nM), and dantrolene (10(-5) M), an inhibitor of calcium mobilization from intracellular calcium stores, all significantly blocked PTH-stimulated osteoclastlike cell formation. Anti-IGF-I antibody (3 micrograms/ml) significantly blocked osteoclastlike cell formation stimulated by 10(-4) M dbcAMP, 10(-4) M Sp-cAMPS, a direct PKA activator, and 10(-5) M forskolin in mouse bone cell cultures. Dibutyryl cAMP, forskolin, and hPTH-(1-34) significantly stimulated mRNA expression of both IGF-I and IGF-binding protein 5 (IGFBP-5) in these cultures, but neither 10(-7) M PMA, a PKC activator, nor 10(-7) M A23187 did. Moreover, anti-IGF-I antibody significantly blocked osteoclastlike cell formation stimulated by the conditioned medium from MC3T3-E1 cells pretreated with 10(-8) PTH-(1-34), which induced IGF-I and IGFBP-5 mRNA expression in these cells. In conclusion, the present study indicates that IGF-I mediates osteoclastlike cell formation stimulated by PTH and that the PKA pathway is involved in its mechanism. However, IGF-I does not seem to be the sole effector molecule to be active in this system.

Animals↗
PubMed1997

In vivo and in vitro effects of Sizofiran on the human neutrophils and the serum opsonic activity.

In this paper, we examine the effects of SPG, which is a well known BRM, both in vivo and in vitro on the neutrophilic ROS production and the serum opsonic activity by the chemiluminescence technique using luminol as a probe. To investigate the in vivo effects, SPG was administered to 12 healthy male volunteers and two phases of enhancement of the neutrophilic ROS production and the serum opsonic activity was observed. In vitro, the addition of SPG showed a dose-dependent suppression. To investigate the mechanisms in these contradictory effects of SPG, supernatants of a lymphocytes culture medium in the presence of SPG with or without mitogen were added to the neutrophils. The addition of supernatants at a lower concentration of SPG (0.01 mg/ml) with mitogens showed significant preventive effects on the neutrophilic ROS production for the duration of incubation. This suggests that cytokines derived from lymphocytes may contribute to the in vivo effects of SPG. SPG can play an important role in the host's defense against microbe infections by enhancing it's effect on non-specific immunity when administered in vivo.

Adjuvants, Immunologic↗
PubMed1997

Helicobacter pylori infection accelerates human gastric mucosal cell proliferation.

Helicobacter pylori causes chronic atrophic gastritis and intestinal type gastric cancer arises against a background of atrophic gastritis. Increased proliferation of epithelial cells is an important indicator of increased risk for gastric adenocarcinoma. We investigated gastric mucosal cell proliferation in H. pylori-associated gastritis and the effect of eradication therapy on this proliferation in 45 patients endoscopically diagnosed (31 with persistent eradication and 14 in whom H. pylori) recurred. H. pylori status was determined by culture and histology in biopsied specimens from the gastric antrum and corpus. Eradication of the infection was defined as reversal to negative on both tests. In vitro Ki-67 immunostaining of endoscopic biopsy specimens was used to measure mucosal cell proliferation in H. pylori-associated gastritis before and after therapy. The proliferative zone was defined as the distance of Ki-67-positive gastric epithelial cells between the highest and the lowest cells. In patients in whom H. pylori was eradicated, cell proliferation in both the antral and corpus mucosa had decreased 4 weeks after completion of the eradication therapy (P < 0.01, P < 0.001), and 6 months later, it had markedly decreased (P < 0.05, P < 0.05) and returned to normal. In patients in whom H. pylori recurred, only antral epithelial cell proliferation was reduced 4 weeks after eradication therapy, but when H. pylori recurred, determined by culture and histology, cell proliferation level was the same as that before eradication. These results suggest that H. pylori infection accelerates cell proliferation in gastric mucosa and may play a causal role in the chain of events leading to gastric carcinoma.

Amoxicillin↗
PubMed1997

Real-time imaging of neural activity during binaural interaction in the guinea pig auditory cortex.

Spatio-temporal patterns of binaural interaction in the guinea pig auditory cortex (AC) were observed using optical recording with a 12 x 12 photodiode array and a voltage-sensitive dye. The amplitudes of the sound-induced light signals from the cortex were transformed into sequential two-dimensional images every 0.58 ms. Binaural sound stimuli evoked an excitatory response followed by a strong inhibition, and contralateral stimuli evoked a strong excitatory response followed by a weak inhibition. Ipsilateral sound stimuli evoked a weak response. Binaural stimulation induced two types of ipsilateral inhibition: a fast binaural inhibition which was detected only after the contralateral and ipsilateral responses were subtracted from the binaural responses, and which appeared 12-25 ms after the onset of stimulation, and a slow binaural inhibitory effect which was clearly observed in the binaural responses themselves, appearing 70-95 ms after the onset of stimulation. The fast binaural inhibition was observed in the same area as the contralateral excitatory response. The inhibited area became stronger and more widespread with increasing intensity of ipsilateral stimulation. We did not observe the specialized organization of binaural neurons as electrophysiologically found in the cat AC, in which binaural neurons of the same binaural response type are clustered together and alternate with clusters of other response types.

Acoustic Stimulation↗
PubMed1997

Optical study of spatiotemporal inhibition evoked by two-tone sequences in the guinea pig auditory cortex.

Spatiotemporal response patterns in the anterior and dorsocaudal fields of the guinea pig auditory cortex after two-tone sequences were studied in anesthetized animals (Nembutal 30 mg kg-1) using an optical recording method (voltage-sensitive dye RH795, 12 x 12 photodiode array). Each first (masker) and second (probe) tone was 30 ms long with a 10-ms rise-fall time. Masker-probe pair combinations of the same or different frequencies with probe delays of 30-150 ms were presented to the ear contralateral to the recording side. With same-frequency pairs, responses to the probe were inhibited completely after probe delays of less than 50 ms and the inhibition lasted for more than 150 ms, and the inhibition magnitudes in different isofrequency bands of the anterior field were essentially the same. With different-frequency (octave-separated) pairs, responses to the probe were not inhibited completely even after probe delays as short as 30 ms, and the inhibition lasted only for 110-130 ms. Inhibition magnitudes were different from location to location.

Acoustic Stimulation↗
PubMed1997

Hemolytic uremic syndrome following autologous peripheral blood stem cell transplantation in a patient with malignant lymphoma.

Hemolytic uremic syndrome (HUS) has been reported in patients receiving bone marrow transplantation. However, only a few cases of HUS following autologous peripheral blood stem cell transplantation (PBSCT) have been reported. We present a case of HUS developing after autologous PBSCT in a 40-year-old man with non-Hodgkin's lymphoma. It appears that the chemotherapeutic agents administered during the conditioning regimen for PBSCT may have played an important role in the development of HUS in our patient. In the present case, the combination therapy of vincristine, methylprednisolone, and ticlopidine hydrochloride was effective.

Adult↗
PubMed1997

A new semi-solid agar dilution method for determining amoxycillin, clarithromycin and azithromycin MICs for Helicobacter pylori isolates.

The MICs of amoxycillin, clarithromycin and azithromycin for 26 strains of Helicobacter pylori were determined using Mueller-Hinton semi-solid agar (SSA) without CO2 incubation, as in the conventional agar dilution method. The tested H. pylori strains grew satisfactorily in the SSA method within 48 h of incubation. Reasonable values of MICs of three antibiotics for these strains were obtained by this method, avoiding the inactivation of macrolides due to acidification of the medium. By this method, the MICs of the antibiotics for the reference strains were within the acceptable NCCLS ranges for quality control.

Amoxicillin↗