Biomedical subjects
Publications and source records attributed to K Tobise.
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The effects of methysergide (a serotonin antagonist) on the pulmonary circulation were investigated experimentally. Twenty-eight mongrel dogs were anesthetized with sodium pentobarbital, and thoracotomy was carried out. A micro-tip pressure transducer was inserted into the pulmonary trunk and an electromagnetic flow probe was placed around it. Aortic and left atrial pressure were also measured. Three different doses (100, 250 and 1000 micrograms/kg) of methysergide and a dose of 3 micrograms/kg of serotonin were infused rapidly into the right atrium through a catheter inserted transvenously. Then, all parameters were continuously recorded. Furthermore, moduli of pulmonary vascular input impedance were calculated from pulmonary pressure and flow waves by means of Fourier analysis. The administration of each dose of methysergide resulted in an increase in pulmonary arterial pressure and resistance and a decrease in heart rate. With the highest dose of methysergide, the aortic pressure was decreased moderately. No increase in pulmonary vascular resistance was observed even after serotonin administration under the treatment with methysergide(1000 micrograms/kg). Although the characteristic impedance did not change significantly with methysergide, the impedance modulus at 0-frequency and low frequencies increased slightly in magnitude. The shift of the frequency of the impedance minimum was slight in comparison with the case of serotonin. These findings were similar to those obtained with serotonin, in general, The results have shown that methysergide produces serotonin-like effects on the pulmonary circulation, and have suggested that it may stimulate serotonin receptors in the pulmonary vascular smooth muscles as a partial agonist. It is desirable that serotonin antagonist have little effect by itself on the pulmonary circulation, in order to determine the role of serotonin in some pulmonary circulatory disturbances.
Pulsatile pressure-flow relationships were studied in order to clarify the mechanical property of the pulmonary vascular bed. The left or right lower lobe of the dog was excised. Then, its pulmonary artery, pulmonary vein and bronchus were attached to a perfusion system. The lobe was perfused either via pulmonary artery (antegrade perfusion) or via pulmonary vein (retrograde perfusion) employing Harvard 1405 pulsatile pump. Positive pressure ventilation was maintained by a respirator throughout the experiment. From the pressure and flow wave, pulmonary vascular input impedance and total hydrauric power were computed by means of Fourier analysis. Pulmonary vascular resistance during retrograde perfusion was lower than that obtained during antegrade perfusion in a high flow state. The data suggests that the pulmonary vascular bed shows more passively distensible character during retrograde perfusion compared with antegrade perfusion. In the control flow state (inflow pressure of 15 mmHg and outflow pressure of 5 mmHg), however, above mentioned relationship was reversed (statistically significant). As outflow pressure was elevated, also, pulmonary vascular bed showed more remarkable distensibility during retrograde perfusion than during antegrade perfusion. With regard to the input impedance modulus and phase, there is no difference between the antegrade and retrograde perfusion of an excised lung lobe. Therefore, pulmonary arterial tree and pulmonary venous tree have a similar mechanical property, which determines the pulmonary vascular impedance. The rate of pulsatile power (Wp)/total hydrauric power (Wt) was 15-25% during antegrade perfusion, and Wp/Wt had minimum value at an inflow pressure of 14.5-15.5 mmHg. It may be stated that this value indicates the best condition for the pulmonary arterial smooth muscle.
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BACKGROUND: Malignant fibrous histiocytoma (MFH) of the lung is rare. Early diagnosis is very important because of its poor prognosis. Long-term survivors of pulmonary MFH are patients who had surgical resection. When the patient can undergo surgery after a prompt diagnosis, the prognosis improves more than with other therapy. However, it is not easy to establish the diagnosis of thoracic MFH. In general, the small fragments from bronchial or percutaneous transthoracic fine needle aspiration (FNA) biopsies are inadequate for cytologic or pathologic analysis. Bronchial brushing cytology is greatly superior to FNA cytology because one can obtain a large amount of cells. Therefore, bronchial brushing cytology may play a useful role in diagnosis when endobronchial involvement is found. CASE: A 65-year-old female was admitted with a cough, yellow sputum and exertional dyspnea. A chest roentgenogram showed a 12 x 12-cm mass in the left lung field. Bronchial brushing cytology revealed many fibroblastlike, histiocytelike, bizarre and multinucleated giant cells in a background of necrosis. Atypical mitotic figures were also found. The cytologic findings strongly suggested MFH. Although the pathologic findings from FNA biopsy showed storiform clusters structured by pleomorphic, fibroblastlike cells with bizarre nuclei and mitotic figures, the material was too small to diagnose it definitively. Six months later the patient died. An autopsy confirmed the diagnosis of MFH: the typical storiform clusters were composed of many fibroblastlike and histiocytelike cells that were positive for CD68 (PGM1) antibody. CONCLUSION: Bronchial brushing cytology may be a useful method for early, definitive diagnosis of MFH. The presence of pleomorphic, spindle-shaped fibroblastlike and histiocytelike cells with the clusters showing a storiform pattern may permit the diagnosis of MFH.
Probucol administration of 4 weeks produced torsades de pointes associated with exacerbated QT interval prolongation in a 36-year-old woman with Romano-Ward syndrome. With discontinuance of probucol, the QT interval corrected for rate shortened from 620 msec to 500 msec and ventricular ectopic beats disappeared completely. Although probucol is known to prolong the QT interval, associated ventricular tachyarrhythmia has not been reported in humans as yet. This case suggests that one should be very careful in the administration of probucol to patients with long baseline QT intervals.
A 46-year-old woman was admitted to the hospital because of dyspnea and palpitation. Physical examination showed severe anemia and cardiac distress. Telangiectases were found in the conjunctivas, lips and oral mucosa. Chest roentogenogram showed an enlarged cardiac silhoutte and multiple coin lesions in both lower lung fields. We diagnosed her as Rendu-Osler-Weber disease (ROW). The angiographic studies showed hemangioma in the foramen of Monro, bilateral multiple pulmonary arteriovenous fistulas, and hepatic arteriovenous fistula with a large distortion of the proper hepatic artery. Although associated vascular dysplasias have been described in patients with ROW, there is no reports on ROW in which multiple vascular abnormalities concomitantly existed such as the present case. In 163 detailed cases of ROW in Japan, the frequency of vascular lesions was summarized, and this result showed that the vascular lesions of the lung were more frequent than that of the liver or brain, in comparison with countries in Europe and America. It is very important for diagnosis and its prognosis to perform a detailed angiographic examinations and to demonstrate the precise sites of the vascular dysplasias in patients with ROW.