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Biomedical subjects

N Hara

Publications and source records attributed to N Hara.

At least 235 records · Page 13Linked to original sources
PubMed1995

Toxic and nontoxic effects of ouabain on the transmitter release from frog motor nerve terminals.

Toxic and nontoxic effects of ouabain were investigated on frog neuromuscular preparation by measuring the mean quantal content of endplate potentials elicited during repetitive nerve stimulation. In the untreated normal muscles, application of 10 microM ouabain gave rise to a slow exponential increase in the transmitter release (toxic ouabain effect) with a certain delay. This delay was increased with either 100 microM amiloride, a Na(+)-Ca2+ exchange blocker, or the intracellular loading of 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA), a specific intracellular Ca2+ chelator. Measurements of frequency augmentation-potentiation (FAP) revealed a specific nontoxic effect of ouabain: 1 microM ouabain pivoted the long-linear FAP relation counter-clockwise without altering the intercept on the ordinate. Contrary to their action in the toxic effect, both 100 microM amiloride and the intracellular loading of BAPTA failed to counteract the nontoxic effect of 1 microM ouabain. The present results suggest that the toxic and nontoxic effects of ouabain are of different entities. The ouabain-sensitive subtype of Na+,K(+)-ATPase, which is abundant in neural tissues, seems to play a specific role in the process of nontoxic potentiation of transmitter release.

Amiloride↗
PubMed1995

[The effect of unpleasant mood and involvement on information processing in persuasion].

This study investigated the effect of unpleasant mood and involvement on the processing of persuasive communication. It was hypothesized that unpleasant mood would facilitate the processing of a message on a highly self-involving topic but inhibit that on a low self-involving topic. Mood-inducing films were used to induce unpleasant or neutral mood. Results indicated that unpleasant mood facilitated cognitive processing of the message in both the conditions of high and low involvement. Moreover, subjects in unpleasant mood evaluated plausibility of the message and communicator's credibility and likability more carefully than subjects in neutral mood. Consistent with the findings of Schwarz, Bless, and Bohner (1991), the present results indicate that unpleasant mood facilitates elaborated processing.

Adult↗
PubMed1995

[A case of post-traumatic arteriovenous fistula of the subclavian artery].

A 67-year-old woman was admitted to our hospital for a complete medical evaluation of a pulmonary nodule on a chest X-ray film, which was found during an annual check-up. A loud bruit was audible over the left chest and the supraclavicular region. Computerized tomography (CT) scan and magnetic resonance imaging revealed an arteriovenous fistula from a branch of the left subclavian artery into the paravertebral veins. Angiography disclosed that the arteriovenous fistula was fed by the left costocervical artery. Transarterial embolization of the arteriovenous fistula was done with 5 mechanical detachable coils and 2 micro coils. Postembolization angiography showed a marked decrease in blood flow and near-elimination of the arteriovenous fistula. The shrinkage of the arteriovenous fistula was also observed on CT scan. This patient had been in a traffic accident, and had been clinically well before the accident. Post-traumatic arteriovenous fistula was strongly suspected, because a pulmonary nodule on chest X-ray film and a bruit were found after a traffic accident.

Accidents, Traffic↗
PubMed1995

[Studies on the microtubules assembly of multidrug-resistant human leukemic cells].

The development of drug resistance in cancer cells is a significant clinical problem for the successful cancer chemotherapy. Since the cytoskeleton, including microtubules, may be involved in modulating cellular signal transduction, morphological and structural changes, the microtubules assembly of multidrug resistant cells was examined using Confocal Laser Microscope MRC500 system (Bio Rad). In this study, multidrug resistant cells were established by the continuous exposure to ADR(adriamycin) starting with 20 nM up to 1 microM. The expression of MDR-1 (multidrug resistance) gene was detected in K562 leukemia cells and to more extent in the multidrug resistant K562/ADR cells, but not in HL-60 leukemia cells and multidrug resistant HL-60/ADR cells by RT-PCR method. The chronological features of microtubules assembly in the parent cell lines were lost on day 3, after incubation with 20nM of ADR. In accordance with development of drug resistance, the microtubules assembly appeared to be more dense and stronger than that of parent cells. During the development of drug resistant cells, the ADR-accumulation in the nucleus was decreased according to the increase of microtubules assembly. In the case of incubation with 0.5 microM colcemid, an inhibitor of microtubules polymerization, for 3 hours, the stainings of microtubules were lost their fine network and appeared to be diffuse and dot-like pattern. At the same time, both untreated HL-60/ADR and K562/ADR showed the decrease of ADR-accumulation, but the accumulations both colcemid treated resistant cells were increased the same level of their parent cells at the point of 120 min. These results suggested that the resistance to ADR in human leukemia cells correlated with microtubules assembly, and the microtubules assembly played an important role of drug resistance with or without MDR-1 gene overexpression.

Demecolcine↗
PubMed1995

[A case of pulmonary eosinophilic granuloma and diabetes insipidus].

A 31-year-old man was admitted to our hospital because of a sudden onset of thirst, polyposia, and polyuria. Five years previously he had been admitted to our hospital because of a dry cough. On the first admission, the chest X-ray film had shown reticular shadows and bullous changes in both upper lung fields. Histological examination of a transbronchial lung biopsy specimen had revealed that the nodular lesion in the interstitium of the alveolar lesion consisted of an aggregate of many Langerhans cells with pale cytoplasm and partly convoluted nuclei. In addition, immunoperoxidase stain for S-100 protein had been strongly positive in numerous Langerhans cells in a bone biopsy specimen from a left mandibullar lesion, which is the same histological appearance as the lung lesion. A diagnosis of pulmonary eosinophilic granuloma had been made. The course after discharge was not progressive without treatment for 5 years, but the patient suddenly began to have thirst, polyposia, and polyuria. Dehydration, vasopressin tests, and the findings of MRI indicated diabetes insipidus due to a pathological change in the pituitary gland. Although diabetes insipidus is known to be a common complication of pulmonary eosinophilic granuloma, only 9 cases have been reported in Japan.

Adult↗
PubMed1995

Effect of polychlorinated biphenyls and polychlorinated dibenzofurans on leukocyte in peripheral blood and bronchoalveolar lavage fluid.

In order to investigate immunological abnormalities induced by polychlorinated biphenyls and polychlorinated dibenzofurans, we have performed bronchoalveolar lavage in the rats given polychlorinated biphenyls and polychlorinated dibenzofurans. We have administrated 5.0 mg of polychlorinated biphenyls or 0.5 mg of polychlorinated dibenzofurans to Sprague-Dawley rats intraperitoneally. Four weeks after the administration, mild necrosis of bronchiolar Clara cells and mild edema associated with chronic inflammatory infiltration in the alveoli were seen in both groups. In the peripheral blood, percentage of T-lymphocyte, helper T-cell and suppressor T-cell decreased significantly both in polychlorinated biphenyls and polychlorinated dibenzofurans given rats. On the other hand, in the bronchoalveolar lavage fluid, percentage of T-cell increased only in polychlorinated dibenzofurans given rats and percentage of suppressor T-cell increased in both groups. O2- release by alveolar macrophage increased significantly both when stimulated with wheat germ lectin and with phorbol myristate acetate. These results indicate that immunological alternation may be different between peripheral blood and respiratory system as one of the target organs of these chemicals. Further examination is needed for the analysis of immunological abnormalities in the target organs of polychlorinated biphenyls and polychlorinated dibenzofurans poisoning.

Animals↗
PubMed1995

[Surgical treatment for acute pulmonary thromboembolism occurring 9 months after an operation for lung cancer].

Successful surgery for pulmonary thromboembolism is reported, with emphasis on the indication and the necessity of cardiopulmonary bypass. Surgical treatment is indicated for patients with localized large thromboemboli not amenable to medical management. Surgery is also an option for patients in whom medical treatment is not effective. In the present case, the etiology was unknown and there was no history of deep vein thrombophlebitis of the legs, which suggested that the cause was an embolus from a lung tumor that had already been treated surgically. Histological examination revealed a fresh blood thrombus, 9 months after pulmonary resection. This patient had syncope at the onset of the pulmonary thromboembolism (major vessel type) without circulatory collapse.

Adenocarcinoma↗
PubMed1995

Successful treatment of chronic necrotizing pulmonary aspergillosis with intracavitary instillation of amphotericin B--a case report.

We present an unusual case of 30-year-old man who was admitted to our hospital with dysesthesia of the limbs and skin eruptions. Polyarteritis nodosa was diagnosed based on the histopathological examination of sural nerve and renal biopsies. A month after initiation of corticosteroid therapy, a small infiltrative shadow was detected in the right mid-lung field by chest X-ray. Aspergillus infection was suspected based on a culture of bronchial lavage fluid. Despite intravenous administration of the antifungal agents, miconazole and fluconazole, a thin-walled cavity with a fungus ball gradually formed in the infiltrative lesion. The patient's clinicopathological findings were consistent with a diagnosis of chronic necrotizing pulmonary aspergillosis, a rare aspergillus infection in the lung. Treatment with intracavitary instillation of amphotericin B proved effective.

Adult↗
PubMed1995

[Comparison of complement activation between tuberculous and malignant pleuritis].

Complement activation products in pleural effusions were studied to clarify the causes of tuberculous and malignant pleuritis. Pleural SC5b-9, an activation product of complement common pathway, was significantly higher in tuberculous effusions than in malignant ones. In the tuberculous effusions, the levels of SC5b-9 and LDH (a marker of tissue damage) were significantly correlated, but in the malignant effusions these two values were not correlated. In the tuberculous effusions, SC5b-9 and Bb values were significantly correlated, but SC5b-9 and C4d were not, and nor were SC5b-9 and immune complex. In the malignant effusions, SC5b-9 and Bb values were low and were not significantly correlated. These results suggest that complement activation plays a significant role in tuberculous pleuritis, but not in malignant pleuritis.

Antigen-Antibody Complex↗
PubMed1995

[Analysis of DNA content in primary colorectal carcinoma and lung metastasis].

We analyzed DNA content of resected primary colorectal carcinoma and lung metastasis by flow cytometry. Of the 14 primary lesions, 5 cases showed diploid pattern, 9 cases aneuploid pattern. In contrast, 12 metastatic lung lesions of 19 showed diploid pattern and 7 lesions aneuploid pattern. DNA index of primary and metastatic lesions was 1.4 +/- 0.4 and 1.2 +/- 0.2, respectively (p = 0.08). In combination of DNA ploidy pattern between primary and metastatic lesions, there were 11 in which ploidy pattern was identical, 1 in which metastasis was aneuploid and primary was diploid, 7 in which metastasis was diploid and primary was aneuploid. Four year, survival rate from operation of metastasis was better in diploid pattern than in aneuploid pattern, but it was not significant. These results indicate that patients who have operative indication of metastasis from colorectal carcinoma have metastatic tumor which shows relatively good biological behavior (diploid tumors) and that there are heterogeneity of ploidy pattern between primary and metastatic lesions.

Adult↗
PubMed1995

[Inhibitory non-adrenergic, non-cholinergic nerves and nitric oxide].

We studied the role of nitric oxide and inhibitory non-adrenergic, non-cholinergic (i-NANC) nerves in the regulation of airway responsiveness in anesthetized and mechanically ventilated cats. Vagal stimulation caused marked bronchodilation in the cats with sustained bronchoconstriction in the presence of atropine and propranolol. The bronchodilation evoked by vagal stimulation was completely abolished by hexamethonium (2 mg/kg). L-NG-nitroarginine methyl ester (L-NAME; 8 mg/kg + 2 mg/kg/min) significantly suppressed the relaxation evoked by vagal stimulation; the effect was particularly noticeable soon after the stimulation. Hexamethonium significantly increased airway responsiveness to serotonin: the PC200 decreased from 0.346 mg/ml (GSEM 1.23) without hexamethonium to 0.44 mg/ml (GSEM 1.63) with hexamethonium (p < 0.05). L-NAME shifted the dose-response curve to serotonin significantly to the left: the PC200 decreased from 0.261 mg/ml (GSEM 1.,40) without L-NAME to 0.056mg/dl (GSEM 1.38) with L-NAME (p < 0.05). Inhalation of citric acid (20%) caused marked bronchodilation during serotonin-induced bronchoconstriction. This bronchodilation occurred in the presence of atropine and propranolol and was inhibited by hexamethonium, therefore it was probably caused by a reflex mediated by i-NANC nerves. Furthermore, the bronchodilation induced by i-NANC nerves was significantly suppressed by L-NAME. These results suggest that nitric oxide is an important i-NANC transmitter that can modulate airway responsiveness.

Animals↗
PubMed1994

Cloning and expression of cDNA for arginine-specific ADP-ribosyltransferase from chicken bone marrow cells.

Two arginine-specific ADP-ribosyltransferase cDNAs (designated AT1 and AT2) were cloned from chicken bone marrow cells. Each cDNA encodes a different peptide of 312 amino acid residues. Homology of deduced amino acid sequences between AT1 and AT2 was 78.3%. We found all six combined peptide sequences of 222 amino acid residues derived from purified chicken heterophil ADP-ribosyltransferase (Mishima, K., Terashima, M., Obara, S., Yamada, K., Imai, K., and Shimoyama, M. (1991) J. Biochem. (Tokyo) 110, 388-394) in the deduced amino acid sequence of AT1, with two amino acid mismatches. Arginine-specific ADP-ribosyltransferase activity was detected in culture medium of COS 7 cells transiently transfected with AT1 cDNA, while activity from the cells transfected with AT2 cDNA was found in both culture medium and cell lysate. AT1 transferase required 2-mercaptoethanol for the activity. The activity was inhibited in the presence of NaCl while AT2 enzyme was activated by either agent. On zymographic in situ gel analysis, estimated molecular masses of the AT1, AT2 and purified chicken heterophil transferases were 32, 34, and 27.5 kDa, respectively. Northern blot analysis with specific probes to AT1 or AT2 cDNAs revealed about a 1.5-kilobase message in chicken bone marrow cells but no signals were observed in heterophils, spleen, and liver of chicken or human HL-60 cells. Highly conserved regions were observed among the deduced amino acid sequences of AT1, AT2, rabbit skeletal muscle transferase, and rodent T-cell surface antigen RT6s.

ADP Ribose Transferases↗
PubMed1994

A flow cytometric assay reveals an enhancement of phagocytosis by platelet activating factor in murine peritoneal macrophages.

Phagocytosis of fluorescein isothiocyanate-labeled latex beads by peritoneal macrophages from thioglycollate-stimulated mice was examined in vitro by means of flow cytometry. This assay revealed that platelet activating factor (PAF), a known inflammatory mediator, enhanced the phagocytosis in a dose-dependent manner. The enhancement was completely suppressed by a PAF antagonist, Y-24180, and partly suppressed by another antagonist, CV-3988. The phagocytosis of both nonstimulated and PAF-stimulated macrophages was suppressed in Ca(2+)-free ethylene glycol bis(beta-aminoethyl ether) N,N'-tetraacetic acid-containing solution, but the phagocytosis was enhanced by PAF even in this solution. These results suggest that phagocytosis by macrophages is enhanced by PAF in allergic and inflammatory reactions.

Animals↗
PubMed1994

Ipratropium bromide protects against bronchoconstriction during bronchoscopy.

Pulmonary function is reportedly impaired by fiberoptic bronchoscopy. We investigated the effect of two anticholinergic agents, intramuscular atropine and inhaled ipratropium bromide, on bronchoconstriction in 29 patients who were undergoing diagnostic bronchoscopy. The patients were divided into three groups; the first received 0.5 mg of atropine intramuscularly; the second took four puffs of 0.02 mg ipratropium bromide aerosolized by a metered-dose inhaler, and the third inhaled four puffs of a placebo. Fifteen minutes later a standardized topical anesthetic, lidocaine, was administered, and a bronchoscopic examination was performed. Pulmonary function was measured before and 15 minutes after each step. Pulmonary function was not affected by the treatment with anticholinergics or the placebo. In the placebo and the atropine groups, the topical anesthesia produced significant reductions in forced expiratory volume in 1 second (FEV1) and peak expiratory flow rate (PEFR); further reductions in these values were observed after bronchoscopy. In the group treated with ipratropium bromide there were no significant changes in FEV1 and PEFR after topical anesthesia. Bronchoscopy induced significant reductions in FEV1 and PEFR, but the changes were significantly smaller than those seen in the placebo and atropine groups. The results suggest that the deleterious effect of bronchoscopy on pulmonary function is due to topical lidocaine anesthesia and to the bronchoscopic examination itself. Inhaled ipratropium bromide protects against these deleterious effects, whereas intramuscular atropine does not.

Administration, Inhalation↗
PubMed1994

Airway epithelial cells modulate cholinergic neurotransmission in dog trachea.

We investigated the effects of epithelial cells on excitatory cholinergic neurotransmission in dog trachea, to shed more light on the role of airway epithelial cells in regulating airway responsiveness. Airway epithelial cells were prepared by an enzymatic dissociation of the tracheal mucosa using protease-free collagenase. Tracheal smooth muscle contractions evoked by electrical field stimulation (EFS) or acetylcholine (ACh) were measured before and after the application of epithelial cells. Isolated and dispersed epithelial cells (3 x 10(5) cells/ml) suppressed the amplitude of the twitch-like contractions evoked by EFS in the combined presence of guanethidine sulfate (10(-6) M) and indomethacin (10(-5) M). In contrast, epithelial cells did not affect the contraction evoked by exogenously applied ACh. Atropine (10(-6) M) or tetrodotoxin (10(-7) M) abolished the contraction evoked by electrical field stimulation. These findings indicate that airway epithelial cells inhibit the excitatory neurotransmission of the vagus nerve, presumably by suppressing the release of ACh. Airway epithelial cells may therefore play an important role in regulating the response of smooth muscle.

Acetylcholine↗
PubMed1994

VIP antagonists enhance excitatory cholinergic neurotransmission in the human airway.

It has been reported that a low concentration of exogenously applied vasoactive intestinal peptide (VIP) suppresses the release of acetylcholine (ACh) from vagus nerve terminals in the ferret and feline trachea. There has been, however, no documentation of the prejunctional action of VIP in the human airway. We observed the effects of VIP and VIP antagonists on cholinergic excitatory neuro-effector transmission in the human bronchus to study the possible role of endogenous VIP on excitatory neurotransmission. In the human bronchus, VIP (10(-10) to 10(-7) M) showed no effect on either the contractions evoked by electrical field stimulation (EPS) or those evoked by ACh. To investigate the possible role of endogenous VIP on the human bronchus, we observed the effects of the VIP antagonists [4-Cl-D-Phe6,Leu17]-VIP and [Ac-Tyr1,D-Phe2]-GRF(1-29)-NH2 on excitatory neuro-effector transmission. Both VIP antagonists (10(-8) M) significantly enhances the contractions evoked by EFS without affecting the ACh sensitivity of smooth muscle cells. These results indicate that VIP antagonists have a prejunctional action that enhances excitatory neurotransmission. This study suggests that endogenous VIP may suppresses ACh release from the vagus nerve terminals in the human airway. It is also suggested that exogenously applied VIP may be inactivated by some mechanism in the human airway.

Acetylcholine↗