Biomedical subjects
Publications and source records attributed to H Koto.
A rare case of cough syncope accompanied by seizure is presented. Interseizure electroencephalogram revealed in this 55-year-old man spikes and sharp waves over the bilateral temporal regions. Bronchodilators and antiepileptic medication effectively controlled cough syncope and seizure in this patient.
A 62 year old man treated with carbamazepine for 3 months developed eczema and acute interstitial pneumonitis. A lymphocyte-stimulation test was reactive to carbamazepine. Withdrawal of the drug resulted in prompt improvement. Only 10 cases of this type of drug-induced lung disease have previously been reported.
To elucidate the role of the axon reflex in the airways, we studied the effects of atropine (10(-6) M) and tetrodotoxin (10(-7) M) on the bradykinin-induced contraction of guinea pig tracheal smooth muscle, with or without pretreatment of the animals with capsaicin. The concentration-response curves to bradykinin (10(-9) to 10(-5) M) were measured in the presence of both indomethacin and propranolol. In the guinea pigs not given capsaicin pretreatment, baseline tension values did not differ before versus after the application of atropine or tetrodotoxin. Tetrodotoxin reduced the bradykinin-induced contraction significantly, but atropine did not change the contraction induced by bradykinin. These observations indicate that bradykinin-induced contraction is potentiated by a neurally mediated action, but that is not mediated by acetylcholine released from the efferent vagal nerve terminals. The contractile response to bradykinin was significantly reduced in the animals treated with capsaicin as compared with those administered vehicle only. Furthermore, in the animals treated with capsaicin, tetrodotoxin did not affect the response to bradykinin. These observations indicate that bradykinin-induced airway smooth muscle contraction is mediated in part by tachykinins released from C-fiber endings, presumably via an axon reflex.
A case of Mycoplasma pneumoniae bronchiolitis with hypoxemia is presented. A 41-year-old man was admitted to hospital because of fever, productive cough and dyspnea with wheezing of one month duration. On admission, bronchial asthma was suspected on the basis of reversible airflow obstruction and sputum eosinophilia. However, despite treatment with bronchodilators, his condition did not improve. Chest film and computed tomogram revealed small nodular shadows and tramlines in the bilateral lower lung fields, and pulmonary function tests indicated peripheral airway obstruction. Serologic titer for Mycoplasma pneumoniae was 1:160. A diagnosis of bronchiolitis due to Mycoplasma pneumoniae was made. Improvement of lung function and roentgenographic findings was observed following administration of erythromycin and doxycycline. The concentrations of prostanoids in sputum were markedly higher than in cases of bronchial asthma, and decreased as he improved. These observations suggest that Mycoplasma bronchiolitis should be considered in the differential diagnosis of wheezing, and that measurement of prostanoids in sputum may be useful in the differentiation of infective bronchiolitis and bronchial asthma.
It has been reported that low concentrations of vasoactive intestinal peptide (VIP) suppress the release of acetylcholine (ACh) from vagal nerve terminals. However, there is little documentation of the neuro-effector transmission of VIP in human airways. In the present study, the effects of VIP on excitatory neuro-effector transmission in the human bronchus were investigated, in comparison with feline trachea. In feline trachea, VIP (10(-10) to 10(-7) M) reduced the amplitude of contractions evoked by field stimulation in the presence of indomethacin (10(-6) M). By contrast, VIP (10(-10) to 10(-9) M) had no effect on ACh-sensitivity of smooth muscle cells. These results indicate that VIP in low concentrations has a pre-junctional action inhibiting excitatory neuro-effector transmission, in addition to a post-synaptic action, presumably suppressing transmitter release from the vagal nerve terminals. On the other hand, in human bronchi, VIP (10(-9) to 10(-7) M) did not affect either contractions evoked by field stimulation or those evoked by ACh. These results indicate that VIP does not exhibit any pre-junctional effects in the human bronchus at these concentrations.
To clarify the mechanism underlying the inhibitory effect of epithelial cells on smooth muscle contraction, we studied two types of human bronchial tissue preparations: (1) "acceptor" bronchial strip without epithelium, (2) "donor" bronchial ring with or without epithelium. We measured the contractile responses of acceptor bronchial strip surrounded by donor bronchial ring to increasing concentrations of acetylcholine (ACh). Removal of the epithelium of the donor bronchial rings significantly enhanced the contractions of the acceptor bronchial strips. Thus, airway epithelium decreases the airway smooth muscle contraction to ACh in human bronchus. The mechanism of this inhibitory effect of airway epithelium was not due to a change in mechanical property of the airway, nor to a change in diffusion path for the chemical mediators. These results suggest that human airway epithelium may have an important role in modulating airway smooth muscle tone, possibly by the release of an epithelium-derived relaxing factor.
Indomethacin suppository and aspirin inhalation reduced the amounts of sputum in the patients with bronchiectasis and chronic bronchitis. A 67-year-old woman with bronchiectasis received indomethacin suppository to relieve the lumbar pain. After the start of indomethacin, a reduction in the amount of sputum was observed and the volume of sputum returned to pretreatment levels after the cessation of indomethacin. Levels of cyclooxygenase products in the sputum during indomethacin was also much lower than their levels after discontinuance of indomethacin. A 64-year-old man with chronic bronchitis was also administered inhaled aspirin to control the sputum volume. Both indomethacin suppository and aspirin inhalation reduced the amounts of sputum. In addition to these cases, a 31-year-old woman with bronchial asthma was tried to control the sputum production with indomethacin, but it had no effect on the sputum volume. It is suggested that these drugs may be useful in the treatment of excessive sputum in bronchiectasis and chronic bronchitis.
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Fibrin deposition is prominent in the course of several forms of pulmonary fibrosis. To elucidate the role of fibrin deposition and fibrinolysis in the process of pulmonary fibrosis, we studied bleomycin-induced fibrosis and the effect of urokinase on it. Beagle dogs were injected intramuscularly 20 times with bleomycin in doses of 2 and 6 mg/kg body weight every other day. Intravenous urokinase treatment was subsequently performed with 3,000 units daily for 40 days and 9,000 units twice daily for 70 days. Histopathologic examination of the lungs of dogs receiving bleomycin alone revealed fibrosis. The lungs of bleomycin-treated dogs which received urokinase had less severe fibrosis and this was confirmed by morphometry with planimetry and the point counting method. Urokinase treatment also diminished the increase of hydroxyproline content of the lung of bleomycin-treated dogs. Decrease of lung tissue fibrinolytic activity assayed by fibrin plate method in bleomycin-treated dogs was also prevented by urokinase. Intravenous urokinase, 24,000 units per day in divided doses, was administered daily in cancer patients with bleomycin treatment. Incidence of pulmonary fibrosis was decreased by urokinase. These data indicate that fibrin deposition and fibrinolysis may have an important influence on the fibrotic process in the lung.
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BACKGROUND: We previously demonstrated that pituitary adenylate cyclase activating peptide (PACAP) inhibits airway smooth muscle contraction and plasma extravasation. OBJECTIVE: We thus hypothesized that PACAP may regulate airway responsiveness through these effects and examined the effects of exogenously applied PACAP on the airway hyperresponsiveness induced by ozone exposure. METHODS: Ozone exposure was carried out in awake, spontaneously breathing guinea pigs using 3 ppm for 2 h. Airway responsiveness to histamine was determined before and 30 and 90 min after the termination of ozone exposure for 2 h in anesthetized animals. Extravasation of Evans blue was measured before and 90 min after the termination of ozone exposure. Either PACAP (10(-6) mol/kg) or vehicle was administered intravenously 60 min after exposure. The airway responsiveness was expressed as the concentration of histamine required to produce a 200% increase in total pulmonary resistance (PC(200)). RESULTS: Ozone exposure caused a significant decrease in PC(200) (n = 5, p < 0.05) 30 min after ozone exposure which persisted 90 min thereafter, thus suggesting that ozone caused airway hyperresponsiveness. PACAP significantly suppressed the increase in airway hyperresponsiveness induced by ozone 90 min after exposure (n = 5, p < 0.05). In contrast, this peptide did not have any effect on plasma extravasation. CONCLUSION: We thus conclude that PACAP decreases ozone-induced airway responsiveness, and, therefore, intravenously administered PACAP may be useful in reversing airway hyperresponsiveness.
BACKGROUND: Inhaled steroids are currently the most important drugs for asthma patients, but compliance tends to be low. Compliance could be improved by reducing the number of daily administrations. OBJECTIVES: In the present study, we compared once- and twice-daily administration of fluticasone propionate (FP) to determine the differences in efficacy. METHODS: Subjects were 40 patients diagnosed with bronchial asthma with stable symptoms and pulmonary functions who were on twice-daily FP administration of 100 microg. There were 14 men and 26 women ranging from 29 to 72 years of age. After a 4-week observation period, subjects were randomized into two administration groups by the envelope method and followed for 8 weeks: group A, once-daily administration (200 microg of FP at night), and group B, twice-daily administration (100 microg of FP in the morning and at night). Clinical symptoms, pulmonary functions and airway responsiveness were compared between these two groups. RESULTS: No significant deterioration in clinical symptoms, pulmonary functions and airway responsiveness were observed in group A compared with group B. CONCLUSIONS: These results demonstrate that once-daily FP administration is as effective as twice-daily administration, and that it may improve the compliance for inhaled steroids.