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Biomedical subjects

K Nakamoto

Publications and source records attributed to K Nakamoto.

At least 55 records · Page 3Linked to original sources
PubMed1996

A new gastric ulcer model induced by ischemia-reperfusion in the rat: role of leukocytes on ulceration in rat stomach.

A new model of gastric ulcer involving damage to the muscularis mucosae was developed by clamping the celiac artery in rat to induce ischemia-reperfusion (I-R) injury. Although erosions with falling off of the gastric mucosa were observed immediately, 24 and 36 hours after the I-R, gastric ulcers involving the injury of muscularis mucosae were observed in the area of gastric glands at 48 and 72 hours after initiation of injury. Administration of omeprazol, a proton pump inhibitor, or pentoxifylline, an anti-leukocyte drug, just after the initiation of injury significantly decreased the total area of ulcers at 72 hours. A combination of omeprazol and pentoxifylline was more effective than either drug alone. An anti-leukocyte adhesion molecule (anti-CD18 antibody) also showed significant inhibitory effect on the development of ulcers at 72 hours and the infiltration of leukocytes into both submucosa and mucosa. These results indicate that in our model, gastric acid together with leukocytes contribute to the development of ulcers following erosions. This model may be used to investigate the mechanisms of the development of gastric ulcer and evaluate antiulcer drugs in a preclinical setting.

Animals↗
PubMed1996

Effects of cigarette smoke on nitric oxide-induced increase in cyclic GMP in nerve terminals of rat cerebral cortex.

Since nitric oxide (NO) has been widely accepted as a novel neuromodulator, which activates soluble forms of guanylate cyclase to increase in guanosine 3':5'-cyclic monophosphate (cyclic GMP) levels, the effect of water-soluble substance in cigarette smoke on cyclic GMP levels were investigated using nerve terminals prepared from rat cerebral cortex. Although the smoke-substance itself failed to affect cyclic GMP levels in the synaptosomes, the smoke-substance significantly inhibited the increases in cyclic GMP levels induced by NO donors. The blocking effect of the smoke-substance was inhibited by concomitant incubation with superoxide dismutase, but not with mannitol. In addition, the effect of smoke-substance was mimicked by products of the xanthine/xanthine oxidase system, but not by nicotine. The effect of smoke-substance was preserved at least 7 days after they were stored at room temperature. Therefore, these results suggest that the smoke-substance may possess long half-lives to produce the radicals which inactivate NO, and to inhibit the increase in cyclic GMP levels in nerve terminals. The interference with NO may explain the part of mechanism in effects of cigarette smoke on neuronal functions.

Analysis of Variance↗
PubMed1995

Protective effect of cystathionine on acute gastric mucosal injury induced by ischemia-reperfusion in rats.

We studied the protective effect of cystathionine on acute gastric mucosal injury induced by ischemia-reperfusion in rats. Under pentobarbital anesthesia, the celiac artery was clamped for 30 min and reperfused. Sixty minutes after the reperfusion, the total area of erosions and thiobarbituric acid-reactive substances in the stomach, as an index of lipid peroxidation, were measured and compared between control and cystathionine-treated groups. Intraperitoneal administration of cystathionine (1-20 mg/kg) 10 min before the ischemia significantly reduced both the total area of erosions and the level of thiobarbituric acid-reactive substances. When cystathionine (10 mg/kg) was administered orally, the significant reductions in the total area of erosions and level of thiobarbituric acid-reactive substances were also observed. There was a good correlation between the total area of erosions and the level of thiobarbituric acid-reactive substances. Cystathionine did not affect blood flow during ischemia-reperfusion. These results indicate that the protective effect of cystathionine on acute gastric mucosal injury induced by ischemia-reperfusion may be due to the scavenging action against superoxide radicals in vivo.

Animals↗
PubMed1995

Nitric oxide inhibition of the depolarization-evoked glutamate release from synaptosomes of rat cerebellum.

Effects of nitric oxide (NO) on release of amino acid transmitter were investigated by superfusion of synaptosomes prepared from rat cerebellum. After constant basal levels of amino acid release were obtained, exposure to a depolarizing concentration of KCl (30 mM) evoked 4.05-, 2.18- and 3.00-fold increases in release of glutamic acid (Glu), aspartic acid (Asp) and gamma-aminobutyric acid (GABA) from synaptosomes. The perfusion with NO-donors inhibited the evoked increases in release of Glu and Asp in a concentration-dependent manner, but not that in GABA release. A membrane-permeable analog of cyclic GMP, but not that of cyclic AMP, caused a similar reduction in the evoked release. The concentration of nitroprusside to increase cyclic GMP levels corresponded to that of nitroprusside to reduce the evoked release. These data suggest that NO may directly act upon the nerve terminals to inhibit release of excitatory amino acid transmitters.

Animals↗
PubMed1995

In vitro study on the effects of trial denture cleansers with berberine hydrochloride.

The antifungal activity of trial denture cleansers prepared with berberine hydrochloride was examined against Candida albicans, C. tropicalis, and C. glabrata. A commercial denture cleanser and a trial denture cleanser that exhibited strong antifungal activity were tested for their effects on Candida spp., the color stability of the dental material, and the surface roughness of acrylic resin plates. The results of these tests revealed that the trial denture cleanser removed 64% to 89% of adhered cells from acrylic resin surfaces and had little effect on the other physical properties tested.

Acrylic Resins↗
PubMed1995

Nitric oxide regulates substance P release from rat spinal cord synaptosomes.

In order to determine whether nitric oxide (NO) acts directly upon nerve terminals to regulate the synaptic transmission at the level of spinal cord, effects of NO-donors on release of substance P (SP) and glutamic acid (Glu) were investigated by superfusion of synaptosomes prepared from the rat spinal cord. Basal levels of endogenous SP and Glu release were 5.99 +/- 2.50 fmol/min/mg of protein and 26.2 +/- 4.8 pmol/min/mg of protein, respectively. Exposure to a depolarizing concentration of KCI evoked 2.7- and 3.8-fold increases in SP and Glu release in a calcium-dependent manner, respectively. Sodium nitroprusside (NP) caused a reduction in the depolarization-evoked overflow of SP in a concentration-dependent manner without affecting its basal release, although it failed to affect either basal or evoked release of Glu. The reduction in SP overflow was also observed by the perfusion with S-nitroso-N-acetyl-penicillamine or membrane-permeable cyclic GMP, but not with cyclic AMP. NP caused the concentration-dependent increases in cyclic GMP levels in synaptosomes. Together with reports that excitatory amino acids stimulate NO synthase and release NO in the spinal cord, these data suggest that there may be an interaction between nerve terminals containing Glu and SP, and that NO may directly participate in the regulation of synaptic transmission in SP-containing nerve terminals, which may be mediated through the activation of guanylate cyclase and the increase in cyclic GMP levels.

Amino Acids↗
PubMed1994

Human papillomavirus not found in squamous and large cell lung carcinomas by polymerase chain reaction.

BACKGROUND: Human papillomavirus (HPV) has been identified not only in anogenital carcinomas, but also in malignancies of other organs, including bronchogenic carcinomas. Previous studies reporting detection of these viruses in lung cancers used mainly in situ hybridization. The authors applied the polymerase chain reaction (PCR) for investigating the occurrence of HPV in bronchial neoplasms. METHODS: Formalin fixed, paraffin embedded tissues of 40 squamous and 7 large cell lung cancers were examined. PCR was done with consensus primers, capable of detecting HPV 6, 11, 16, 18, 31, 33, 52b, and 58. RESULTS: None of the 47 samples contained any of the examined HPV types. CONCLUSIONS: Because the squamous and large cell cancer cases were found not to be associated with HPV infection, this study does not support the potential role of these viruses in the development of lung cancers.

Base Sequence↗
PubMed1994

Ansa-recurrent nerve anastomosis for vocal cord paralysis due to mediastinal lesions.

Recurrent laryngeal or vagus nerve injuries in the mediastinum are repaired rarely because of technical difficulties. Impairment in phonation is especially severe in patients with respiratory dysfunction. We performed a simple and less invasive reconstruction, ansa cervicalis-recurrent laryngeal nerve anastomosis in the neck, to improve phonation in 2 patients. Although the reinnervated vocal cord did not regain normal movement, both of the patients obtained excellent improvement in phonation.

Aged↗
PubMed1994

Carcinosarcoma of the lung. Report of a case and review of the literature.

We describe a case of carcinosarcoma of the lung in a 60-year-old female who was admitted with complaints of productive cough and an abnormal shadow in the chest X-ray. Sputum cytology showed both squamous cell carcinoma and adenocarcinoma cells. Malignant nonepithelial cells were identified in the needle biopsy specimen. Right middle and lower lobectomy was performed to reveal a carcinosarcoma by microscopic and immunohistochemical examination. This case was histologically unusual because it presented multiple carcinomatous elements (squamous cell carcinoma and adenocarcinoma). It was classified as peripheral type according to the clinical classification, showing an extremely poor prognosis. The histogenesis and clinical features of this rare tumor are discussed.

Adenocarcinoma↗
PubMed1993

Influence of temperature of flushing solution on lung preservation.

For lung transplantation the technique of flushing the donor pulmonary vascular bed may provide advantages in lung preservation such as rapid cooling and washout of blood. However, rapid cooling of the ischemic lung may also produce adverse effects. The aim of this study was to compare methods of cold flushing and topical cooling, and to evaluate the effect of temperature of the flushing solution on lung preservation. A total of 25 rabbit lungs were studied. Using an ex vivo rabbit lung model, postischemic function was assessed by the ability of the lung to oxygenate perfused blood and by measurement of pulmonary artery and airway pressures. The lungs in group I were preserved with simple immersion at 10 degrees C for 30 hours. The lungs in groups II through V were flushed with solution containing phosphate-buffered dextran (LPD) at different temperatures (groups II and IV, 10 degrees C; groups III and V, 23 degrees C) and stored at 10 degrees C for various ischemic periods (groups II and III, 30 hours; groups IV and V, 36 hours). Pulmonary vascular resistance during flushing at 10 degrees C was significantly higher than that at 23 degrees C (p < 0.001). Flushing resulted in better preservation than topical hypothermia. Flushing at 23 degrees C resulted in superior postischemic function compared with flushing at 10 degrees C. We conclude that in lung preservation, uniform flushing with LPD solution improves the ischemic tolerance as compared with topical hypothermia, and that flushing with solutions at too low temperatures may have adverse effects on lung preservation.

Animals↗
PubMed1993

Operative approaches for left-sided carinoplasty.

Carinoplasty was performed in 42 patients: 7 with wedge pneumonectomy, 15 with sleeve pneumonectomy, 14 with one-stoma-type carinal reconstruction, 5 with montage-type carinal reconstruction, and 1 other. Diagnoses in the 42 patients consisted of lung cancer in 31 (73.8%), tuberculous stenosis in 10 (23.8%), and tracheobronchial injury in 1 (2.4%). The thoracotomy was on the right side for lung cancer in 77.4% and on the left side for tuberculous stenosis in 80.0% (p < 0.01). Left-sided carinoplasty was performed in 14 patients using four approaches: midline thoracotomy in 1, left thoracotomy in 10, midline sternotomy and left thoracotomy in 2, and bilateral thoracotomies in 1. Left wedge or sleeve pneumonectomy, without right thoracotomy, could be done by midline sternotomy and left thoracotomy but with limited tracheal resection. Left one-stoma-type carinoplasty was undertaken, sacrificing one lobe, as an alternative to pneumonectomy, where an approach drawing the carina down to an aortopulmonary window was considered to be preferable to the drawing-up approach.

Anastomosis, Surgical↗
PubMed1993

[Projects in surgery for lung transplantation].

Lung transplantation was simulated in 9 essential items in the surgical side. The possibility to utilize cardiac death donor instead of cerebral death donor was discussed. The transplant window was shown in a patient with primary pulmonary hypertension. The informed consent must be authorized at the specific meeting. For the pre- and postoperative care, it is essential for surgeon to treat on the team which is consisted of members from the specific regions. With donation, a method of the standardization for graft preservation was shown by statistical analysis of many factors. The level of surgical techniques in Japan have been evaluated to be on the current level. In postoperative care, reimplantation response, infection, and rejection are important factors which have been clinically overcome in preceding institutions. However, a practical method of established diagnosis for acute rejection remain unresolved. In addition, CMV infection will be an unavoidable problem in Japan. The research of immune tolerance has been successfully underwent in experiments to overcome chronic rejection.

Humans↗
PubMed1993

[Evaluation by microneurography of muscle sympathetic nerve activity in myelopathic patients].

The purpose of this study was to observe the functional condition of the muscle sympathetic nerve activity (MSNA) in nine patients with mild myelopathy for which surgery was indicated [mean score 14/17 by Japanese Orthopaedic Association (JOA) cervical myelopathy and 7/11 for thoracic myelopathy]. The MSNA was obtained from the tibial nerve at the popliteal fossa by microneurography. The resting activities and the responses during handgripping were analyzed and compared with those of a control group of nine healthy volunteers and patients with disorders unrelated to myelopathy. The MSNA with the subjects supine was recorded first at rest for 5 min. (rest period), next during exertion of 20% of the maximum voluntary handgripping power for 5 min. (handgripping period), and last at rest for 5 min. (recovery period). The number of MSNA bursts per min. (burst rate) in the group with myelopathy was more than that in the control group (p < 0.05) in all three periods. The response by MSNA to handgripping in the group with myelopathy was higher than that in the control group at the start of handgripping (p < 0.01), and tended to be higher even 5 min. after handgripping ended. The results appeared to demonstrate that MSNA of patients with mild myelopathy for which surgery is indicated is increased in the lower extremities.

Adult↗
PubMed1992

A study on optimal temperature for isolated lung preservation.

Fifty-two heart-lung blocks (grafts) of New Zealand white rabbits were used for determining optimal temperature in lung preservation. Grafts were inflated with room air and preserved by simple surface cooling at arbitrarily determined temperatures for 18 hours. Graft function was assessed by nonrecirculated perfusion with autologous blood. Segmented regression models between functional parameters and preservation temperature (T) were applied for determining optimal temperature. Graft ability was also assessed from the point of view of pulmonary circulation by indocyanine green dilution rate of effluent and histological distribution of carbon particles. Significant segmented regression curves and lines between parameters of effluent oxygen tension (PO2) and wet-dry weight ratio (W/D), and T were obtained as follows: PO2 = 150/(1 + 3208.1[e-1.17T]), p less than 0.01; PO2 = -13.8T + 222.6, p less than 0.05; W/D = 5.0 + 1.5/(1 + 0.0028[e0.94T]), p less than 0.01; W/D = 0.075T + 4.52, p less than 0.05. Optimal temperature for lung preservation by topical cooling was calculated as 8 degrees to 9 degrees C from each intersecting point of regression equations. Analysis of regression curves suggested that the most common hypothermic ischemic injury during preservation by topical cooling is pulmonary vascular obstruction, which might be induced at temperatures lower than the critical temperature of 6 degrees to 7 degrees C. Indocyanine green dilution rate and histological findings supported the results of graft functional parameters.

Animals↗
PubMed1992

[Diseases and operative modes of tracheobronchoplasty].

In 251 patients of tracheobronchoplasty, the disease distribution and the indicative expansion were analysed. The largest series was lung cancer encountered in 49%, followed by thyroid cancer in 20%, posttracheostomy tracheal stenoses, primary tracheobronchial tumors, and tuberculosis in 7-8% respectively, and others in remaining 4%. In lung cancer, two way of operative modes have been tried, which were carinal resection extensively and sleeve or wedge segmentectomy limitedly. Laryngotracheal anastomosis increased applicable cases in thyroid cancer and posttracheostomy subglottic stenosis. Preoperative irradiation for adenoid cystic carcinoma increased the cases for operation. A new carinal reconstruction via the subaortic arch approach for tuberculous stenosis was successfully underwent. End-to-end anastomosis instead of partial suture was advisable in the early stage of traumatic bronchial rupture. Congenital airway malformation is a disease to be divised some operations which might furthermore increase operative modes. In summary, 38 operative modes have been experienced so far, and these might increase in number depending to diseases.

Adolescent↗
PubMed1991

Evaluation of denture cleansers with and without enzymes against Candida albicans.

The fungicidal effect on Candida albicans was evaluated for denture cleansers with and without enzymes (alkaline peroxide type). Three cleansers with proteolytic enzymes showed little yeast lytic ability, while one cleanser with yeast lytic and proteolytic enzymes and one cleanser without enzymes showed slight yeast lytic ability. The results suggested that the activity depended on alkaline peroxide rather than on enzymes. Five denture cleansers showed strong effects.

Acrylic Resins↗