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Biomedical subjects

S Kitamura

Publications and source records attributed to S Kitamura.

At least 307 records · Page 17Linked to original sources
PubMed1997

Transplantation of genetically marked cardiac muscle cells.

We examined the possibility that cardiomyocytes could be genetically marked or modified before being grafted to the heart under conditions applicable to the clinical setting. We used a replication-defective recombinant adenovirus carrying the beta-galactosidase reporter gene, and delivered it to cultured murine fetal cardiac myocytes. Virtually all fetal cardiomyocytes in a primary culture expressed beta-galactosidase 24 hours after recombinant adenovirus infection. These cells were transplanted to the hearts of syngenic adult recipient mice. Expression of the beta-galactosidase gene in the grafted cells was demonstrated by staining with 5-bromo-4-chloro-3-indoyl-beta-D-galactosidase, resulting in a blue color at the histochemical level and an electron-dense deposit on transmission electron microscopic analysis. Gene expression was recognized from 7 days to 12 weeks after transplantation. Implanted cardiomyocytes aligned themselves along the layers of the host myocardium. Formation of gap junctions was demonstrated by transmission electron microscopy. Neither inflammation nor fibrous scar tissue was detectable by histologic analysis. This study demonstrates that ex vivo gene transfer to the heart by means of the adenoviral vector is possible.

Adenoviridae↗
PubMed1997

Purification of NADPH-linked and NADH-linked quinone reductases from liver cytosol of sea bream, Pagrus major.

Quinone reductases in sea bream, Pagrus major, were investigated using menadione as a model quinone. Both NADPH-linked and NADH-linked quinone reductase activities were detected, in varying degrees, in all tissues examined. In the liver, these activities resided in its microsomal and cytosolic fractions. The cytosolic activity was markedly inhibited by cupric sulfate and p-chloromercuribenzoate. However, little effect was observed with dicoumarol, a potent inhibitor of DT-diaphorase. The NADH-linked activity was more resistant to heat inactivation than the NADPH-linked activity. The NADPH-linked quinone reductase was purified from the liver cytosol by chromatography with DEAE-cellulose, hydroxyapatite and AF-Blue Toyopearl. The molecular weight of the enzyme was estimated to be 68,000 by gel filtration and 32,000 by SDS-PAGE. The NADH-linked quinone reductase was purified from the liver cytosol by heat treatment, fractionation with ammonium sulfate and chromatography with phenyl-Toyopearl, hydroxyapatite, DEAE-cellulose and hydroxyapatite. The molecular weight of the enzyme was estimated to be 124,000 by SDS-PAGE and 126,000 by gel filtration.

Animals↗
PubMed1997

The involvement of pertussis toxin-sensitive G proteins in the post receptor mechanism of central I1-imidazoline receptors.

1. To elucidate the possible involvement of pertussis toxin (PTX)-sensitive G proteins in the post receptor mechanism of alpha 2-adrenoceptors and imidazoline receptors, we examined the effect of pretreatment of the central nervous system with PTX on the antidysrhythmic effect of dexmedetomidine, a selective alpha 2-adrenoceptor agonist, and rilmenidine, a selective I1-imidazoline receptor agonist on halothane-adrenaline dysrhythmias in rats. 2. Dexmedetomidine (0, 1.0, 2.0, 5.0 micrograms kg-1 min-1.i.v.) and rilmenidine (0, 1.0, 3.0, 10, 20 micrograms kg-1, i.v.) prevented the genesis of halothane-adrenaline dysrhythmias in a dose-dependent fashion. Both idazoxan (10, 20 micrograms kg-1, intracerebroventricularly (i.c.v.)), an alpha 2-adrenoceptor antagonist with high affinity for imidazoline receptors, and rauwolscine, (40 micrograms kg-1, i.c.v.), an alpha 2-adrenoceptor antagonist with low affinity for imidazoline receptors inhibited the action of dexmedetomidine (5.0 micrograms kg-1, min-1, i.v.), but the inhibitory potency of idazoxan was much greater than that of rauwolscine. While the pretreatment with PTX (0.1, 0.5, 1.0 micrograms kg-1, i.c.v.) did not change the dysrhythmogenecity of adrenaline, this treatment completely blocked the antidysrhythmic property of rilmenidine (20 micrograms kg-1, i.v.) as well as dexmedetomidine (5.0 micrograms kg-1 min-1, i.v.). 3. It is suggested that central I1-imidazoline receptors as well as alpha 2-adrenoceptors may be functionally coupled to PTX-sensitive G proteins.

Adrenergic alpha-2 Receptor Agonists↗
PubMed1997

Mucosal interleukin-1 beta production and acid secretion in enlarged fold gastritis.

BACKGROUND: We have previously shown that eradication of Helicobacter pylori increases acid secretion in H. pylori-associated enlarged fold gastritis. AIM: To investigate whether locally produced interleukin-1 beta is possibly involved in the inhibition of acid secretion in H. pylori gastritis. METHODS: IL-1 beta release from the gastric body mucosa was determined by short-term culture of biopsy specimens in 13 patients with enlarged fold gastritis (all H. pylori-positive), five H. pylori-positive and 10 H. pylori-negative patients without enlarged folds. The acid-inhibitory effect of locally produced IL-1 beta was examined by [14C]-aminopyrine uptake assay using isolated rabbit gastric glands. RESULTS: IL-1 beta release was significantly greater in patients with enlarged fold gastritis, significantly correlated with both basal and tetragastrin-stimulated acid outputs in the H. pylori-positive patients (r = -0.591 and r = -0.641, respectively; P < 0.01), and significantly decreased with concomitant increases in acid secretions after eradication of H. pylori. [14C]-aminopyrine uptake was inhibited by IL-1 beta in a dose-dependent manner. CONCLUSIONS: Increased production of IL-1 beta caused by H. pylori infection is possibly involved in the inhibition of acid secretion in enlarged fold gastritis.

Adult↗
PubMed1997

Purification and characterization of alpha,beta-ketoalkene double bond reductases from bovine eyes.

PURPOSE: To explore the alpha,beta-ketoalkene double bond reductases responsible for xenobiotic metabolism in bovine ocular tissues using trans-phenyl-l-propenyl ketone as a model substrate. METHODS: A mixture of trans-phenyl-l-propenyl ketone, NADPH or NADH, and an enzyme source in 0.1 M K,Na-phosphate buffer (pH 7.4) was incubated for 15 min at 37 degrees C. Phenyl propyl ketone formed was quantified by high performance liquid chromatography (HPLC). RESULTS: The lens, ciliary body, iris, retinal pigment epithelium (RPE)-choroid, retina, and cornea exhibited alpha,beta-ketoalkene double bond reductase activities in the presence of NADPH or NADH. An alpha,beta-ketoalkene double bond reductase was purified to homogeneity from the iris-ciliary body cytosol. The molecular weight was estimated to be 58,000 by gel filtration, and 40,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The enzyme activity was inhibited by dicumarol, quercitrin, indomethacin, disulfiram, and p-chloromercuribenzoic acid. The enzyme exhibited double bond reductase activity toward 2-alkenals as well as alpha,beta-ketoalkenes. Another alpha,beta-ketoalkene double bond reductase was also purified to homogeneity from the lens cytosol. The molecular weight was estimated to be 105,000 by gel filtration and 40,000 by SDS-PAGE. The enzyme activity was inhibited by dicumarol and quercitrin. The enzyme exhibited double bond reductase activity toward some alpha,beta-ketoalkenes. CONCLUSIONS: Two kinds of enzymes responsible for reduction of the carbon-carbon double bond of xenobiotics were purified for the first time from ocular tissues. The molecular weights, substrate specificities, and sensitivities to inhibitors of the enzymes were different from each other.

Alkenes↗
PubMed1997

Differences in aldehyde oxidase activity in cytosolic preparations of human and monkey liver.

This study presents data showing individual differences in aldehyde oxidase activity in human and monkey liver cytosols. When assayed with benzaldehyde as a substrate, a significant inter-subject variation in the activity was found in the human liver preparations. When assayed with N1-methylnicotinamide as a substrate, the inter-subject variation of the activity was also observed, but to a lesser extent compared with that of the activity with benzaldehyde. Similarly, variations in aldehyde oxidase activity were found in the monkey liver preparations when assayed with benzaldehyde or N1-methylnicotinamide. The present study suggested that at least two isozymes of aldehyde oxidase exist in the human liver preparations.

Aged↗
PubMed1997

Menadione-dependent reduction of tertiary amine N-oxide by rat liver cytosol.

This study demonstrates the menadione-dependent reduction of imipramine N-oxide, a tertiary amine N-oxide, to imipramine by rat liver cytosol in the presence of NADH or NADPH. A mechanism for the cytosolic reduction of the tertiary amine N-oxide is proposed. Menadione is converted to its reduced form by a menadione-reducing enzyme such as DT-diaphorase and the reduced pyridine nucleotide, followed by reduction of the tertiary amine N-oxide to the amine by the heme group of catalytic hemoproteins in the presence of reduced menadione as an electron donor.

Animals↗
PubMed1997

Nonenzymatic reduction of brucine N-oxide by the heme group of cytochrome P450.

Evidence showing that cytochrome P450-mediated reduction of brucine N-oxide to brucine by rat liver microsomes proceeds nonenzymatically in the presence of both a reduced pyridine nucleotide and FAD is presented. The microsomal N-oxide reduction appears to proceed in two steps: The first step is reduction of FAD by NADPH or NADH either enzymatically or nonenzymatically. The second step is nonenzymatic reduction of the tertiary amine N-oxide by the reduced flavin and is nonenzymatically catalyzed by the heme group of cytochrome P450.

Animals↗
PubMed1997

Centrally administered calcium increases the maximum vagal activation of baroreceptor reflex control of heart rate in spontaneously hypertensive rats.

Baroreceptor reflex control of heart rate (HR) was examined before and 15 min after intracerebroventricular infusion (i.c.v.) of 10 microliters of high-Ca2+ solution (Ca2+, 16.3 mM) in conscious spontaneously hypertensive (SHR) and Wistar-Kyoto rats (WKY). The slope of the individual regression line of the relation between reflex HR changes (delta HR) and changes in mean arterial pressure (delta MAP) produced by bolus injections of phenylephrine or sodium nitroprusside (delta HR/delta MAP; beats/min/ mm Hg) for bradycardia was significantly less in SHR (-0.60 +/- 0.30; n = 10) than in WKY (-1.78 +/- 0.27; n = 10; p < 0.01) at baseline. The slope increased in SHR during administration of high Ca2+ to -1.39 +/- 0.17 (p < 0.01) but not in WKY: In contrast, no significant changes were observed for the reflex tachycardia both in SHR (n = 7) and WKY (n = 10). Further, we analyzed sigmoidal MAP-HR reflex curves in SHR with i.c.v. of either high Ca2+ (n = 6) or artificial cerebrospinal fluid (aCSF; n = 5). Administration of high Ca2+ reduced the bradycardic plateau and increased HR range without changes in average gain. Our results suggest a modulatory role for central Ca2+ in the baroreceptor reflex control of HR in SHR.

Animals↗
PubMed1997

Enhanced depressor effect of centrally administered high-calcium solution in salt-loaded experimental hypertension.

The depressor effect by oral calcium supplementation is known to be more pronounced in salt-dependent than in renin-dependent hypertension. This study was conducted to investigate the role of central calcium on two different pathophysiologic subtypes of experimental hypertension; (a) salt-dependent, deoxycorticosterone acetate-salt hypertensive rats (DOCA), and (b) renin-dependent, 2-kidney, 1 clip (2-K, 1C) hypertensive rats. In DOCA (n = 10), high-calcium solution (Ca+2, 65.2 mM, 10 microl) given centrally (i.c.v.) elicited a marked decrease in mean blood pressure (MBP; 170 +/- 4 to 138 +/- 5 mm Hg, p < 0.01) with a decrease in heart rate (HR; 390 +/- 18 to 344 +/- 17 beats/min, p < 0.05) lasting for 40 min. In 2-K, 1C (n = 10), high-Ca2+ i.c.v. showed a lesser decrease in MBP (178 +/- 4 to 171 +/- 5 mm Hg) and HR (419 +/- 10 to 395 +/- 12 beats/min) with shorter duration (for 20 min) than in DOCA. This significant depressor and bradycardic response to Ca2+ i.c.v. observed in DOCA was dose dependent at Ca2+ concentrations between 65.2 and 130.4 mM. In DOCA, high Ca2+ i.c.v. reduced the plasma noradrenaline (Nad) concentration significantly (479 +/- 81 to 319 +/- 62 pg/ml, p < 0.05). These results suggest that central Ca2+ plays a more important role in regulating sympathetic nerve activity and BP in salt-dependent than in renin-dependent experimental hypertension.

Animals↗
PubMed1997

Impact of sociodemographic and diabetes-related characteristics on depressive state among non-insulin-dependent diabetic patients.

One hundred and fifty-one non-insulin-dependent diabetic patients were assessed to detect sociodemographic, psychological and disease-related characteristics that were related to depressive state among diabetic patients. Depressive state in the patients was correlated with poor social support and low economic status, premorbid neurotic personality and the presence of complications, retinopathy in particular. However, depressive state did not correlate with age, gender, education, serum level of HbA1C or duration of diabetes. The severity of the depressive state in diabetic patients may vary with the cultural background of the patient and/or the country in which he or she is living. In treating diabetic patients, doctors need to pay special attention to these factors.

Adaptation, Psychological↗
PubMed1997

Identification of calprotectin, a calcium binding leukocyte protein, in human dental calculus matrix.

Calprotectin is a calcium binding protein produced by leukocytes, macrophages and epithelial cells, and its levels in several tissues increase during infections and in many inflamed areas, suggesting that it may be an indicator of inflammatory activity. Osteopontin is a prominent phosphorylated glycoprotein in bone matrix, having calcium binding capacity. Recently, it has been reported that calprotectin and osteopontin are present in urinary stones (pathological mineralized masses in the body), and that these proteins may be involved in their formation. Dental calculus formed by mineralization of dental plaque is an inflammatory factor which may contribute to periodontal disease. It contains many organic components involved in mineralization. We recently found osteopontin molecules in human dental calculus and suggested that the components of its matrix may be similar to those of urinary stones. In this study, we investigated the presence of calprotectin in human dental calculus by immunohistochemical and immunoblotting analyses using a specific antibody for calprotectin. After fixation and demineralization of dental calculi adhered to tooth roots, sections embedded in paraffin were immunoreacted with the antibody for calprotectin and positive immunostaining for calprotectin was observed. Dental calculus proteins were then extracted with EDTA and separated by electrophoresis on 15% polyacrylamide gels. By immunoblotting analysis, 3 or 4 bands were observed at 11, 14.5, 22-25, 28 or 36.5 kDa and these patterns corresponded to those of calprotectin subunits. When non-immune rabbit serum was used instead of calprotectin-specific antibody as a negative control, no immunoreactivity was observed. These findings indicate that calprotectin is associated not only with antibacterial action but also with calcium binding capacity during dental calculus formation.

Calcium-Binding Proteins↗
PubMed1997

The role of mammalian intestinal bacteria in the reductive metabolism of zonisamide.

Zonisamide (1,2-benzisoxazole-3-methanesulphonamide), a new anticonvulsant, is mainly metabolized to 2-sulphamoylacetylphenol by reduction of the benzisoxazole ring. Recent studies have shown that mammalian liver enzymes are responsible for the reduction of zonisamide. Because intestinal bacteria can also mediate the reduction of xenobiotics, this study was designed to evaluate the role of intestinal bacteria in in-vivo reductive metabolism of zonisamide. Treatment of rats with antibiotics significantly reduced the urinary and faecal excretion of 2-sulphamoylacetylphenol after oral administration of zonisamide. Re-contamination of the antibiotic-treated rats with microflora restored the excretion of the metabolite. The caecal contents of the control rats had significant zonisamide reductase activity, whereas little or no zonisamide reductase activity was observed with the caecal contents of the antibiotic-treated rats. Eight pure strains of intestinal bacteria were tested for zonisamide reductase activity and the highest was observed in Clostridium sporogenes. We concluded that intestinal bacteria play a major role in the reductive metabolism of zonisamide to 2-sulphamoylacetylphenol in-vivo.

Aldehyde Oxidase↗
PubMed1997

[A case of fatal pneumonia caused by Legionella pneumophila serogroup 6 developed after drowning in a public bath].

A 57-year-old male was admitted to our hospital because of high fever, productive cough and dyspnea. Six days prior to admission he had an episode of drowning in a public bath. On admission chest X-ray showed wide-spread pneumonia causing severe respiratory distress for which mechanical ventilatory support was started. Despite chemotherapy including erythromycin and rifampicin his condition continued to deteriorate. Chemistry showed marked elevation of CPK and findings of acute renal failure. He eventually passed away with septic shock. During the course Legionellae remained negative with culture of broncho-alveolar lavage fluid. L. pneumophila serogroup 1 (SG1) antigen in the urine was not detected, and no elevation of serum antibody titer was noted. Culture of the material obtained from the lung abscess at autopsy revealed L. pneumophila SG6 and serum antibody titer against SG6 also was found to be extremely high. With this evidence we concluded that this case of pneumonia was caused by L. pneumophila SG6. We believe this is the first reported case of the SG6 pneumonia in Japan. Another remarkable feature of this case was massive rhabdomyolysis pathologically confirmed after autopsy. Although the pathogenesis of this process has not been clarified, there are several case reports of rhabdomyolysis complicated with Legionnair's disease in the past. Therefore, we should bear in mind and pay careful attention while coping with this disease.

Baths↗
PubMed1997

Thoracoscopic wedge resection of blebs under local anesthesia with sedation for treatment of a spontaneous pneumothorax.

We performed thoracoscopic wedge resections of blebs with a stapling device under local anesthesia with sedation in 34 consecutive patients who presented with spontaneous pneumothoraces. The indications for surgery included the absence of parietal pleural adhesions and knowledge of the precise bleb location prior to the procedure. Prior to surgery, 0.5% lidocaine was administered into the pleural space, and IV butorphanol tartrate and diazepam were administered to reduce pain and anxiety during the procedure. In our series, the thoracoscopic procedure resulted in favorable outcomes in all but two patients. There was no evidence of hemodynamic instability or arterial blood gas abnormalities encountered during the procedure. Minor postoperative complications were seen in only three patients (two with air leakage and one with transient atelectasis). One patient had a recurrence of his spontaneous pneumothorax 3 months following the procedure. Therefore, the overall success rate was 91%. We compared the results of this therapeutic modality (group 1) with those of 38 patients who underwent the procedure under general anesthesia (group 2) during the same period. The length of hospital stay was shorter in group 1 than in group 2 (4.5 +/- 1.3 vs 5.8 +/- 1.1 days; p < 0.01). Thoracoscopic wedge resections under local anesthesia are safe and offer the benefit of shorter hospital stays. We believe that this thoracoscopic technique will further simplify the surgical treatment of pneumothoraces without incremental risks.

Adolescent↗
PubMed1997

Cavernous angioma with olivary hypertrophy and contralateral cerebellar diaschisis.

We describe a 66-year-old man with a 20-year history of ataxic gait who suddenly developed diplopia on rightward gaze. Neurologic examination revealed right hemi-ataxia and hemi-hypesthesia, and left internuclear ophthalmoplegia. MRI showed a cavernous angioma in the left tectum, mild right cerebellar atrophy, and left interior olivary hypertrophy. Single photon emission computed tomography (SPECT) imaging demonstrated contralateral cerebellar diaschisis. We discuss the findings and review the literature concerning contralateral cerebellar diaschisis.

Aged↗
PubMed1997

Chemokines in the bronchoalveolar lavage fluid of patients with sarcoidosis.

We measured the levels of interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1) in the bronchoalveolar lavage (BAL) fluids from 27 patients with active pulmonary sarcoidosis and examined the relationship between chemokine levels and some clinical manifestations. The levels of two chemokines were assessed by enzyme-linked immunosorbent assay. There were significant positive correlations between the absolute number of lymphocytes and MCP-1 levels. The level of MCP-1 was significantly higher in the group with age at onset of over 50 year than that in the group with age at onset under 30 year. There were no significant differences between the non-smokers and smokers, or among the groups of patients classed according to stages. We conclude that MCP-1 can play an important role in the pathogenesis and clinical course of pulmonary sarcoidosis, although further analysis is needed to delineate the exact role of IL-8.

Adolescent↗