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Biomedical subjects

T Isawa

Publications and source records attributed to T Isawa.

At least 73 records · Page 4Linked to original sources
PubMed1980

Effect of non-filtered and filtered cigarette smoke on mucociliary clearance mechanism.

Acute effect of a short-term exposure to cigarette smoke on mucociliary clearance mechanism was studied in 69 anesthetized dogs. A tracer material, 99mTc-MAA (macroaggregated albumin), was placed in the right main bronchus near the carina 2 min after completion of exposure and its migration distance on the tracheal mucosa with time was assessed by a scintillation camera, and the mean migrating velocity (MMV) was calculated. The average MMV values were 12.0 +/- 1.0 (mean +/- S.E.) mm/min in the control dogs, while the values were 11.6 +/- 1.5, 8.3 +/- 2.2, 3.3 +/- 0.8, and 4.2 +/- 2.3 mm/min in the dogs which smoked 1, 3, 5 and 8 cigarettes, indicating that there was an inverse correlationship between the number of cigarettes smoked and the MMV values. When cigarette smoke was filtered through a glass fiber filter, the average MMV values were 7.0 +/- 0.5 and 1.3 +/- 0.9 mm/min in the dogs which smoked 5 and 8 cigarettes respectively, suggesting that once the number of cigarettes amounted to eight, even cigarette smoke filtered through a glass fiber filter was as detrimental to the mucociliary clearance mechanism as the non-filtered cigarette smoke.

Animals↗
PubMed1980

Effect of alveolar hypercapnia on regional pulmonary perfusion.

The effect of alveolar hypercapnia under a wide range of alveolar oxygen tensions was assessed in the right upper lobe of the normal dogs and the dogs with the reimplanted right lung. To induce alveolar hypercapnia by artificial ventilation of the right upper lobe, gas mixtures of differing oxygen fractions containing 10% or 20% CO2 were used as exchange gases for the right upper lobe. The concurrent alveolar hypercapnia had little superimposed effect on the regional vascular responses to a wide range of alveolar oxygen tensions in the normal and the reimplanted denervated lung lobe. Under an extreme alveolar hyperoxia, however, the concurrent alveolar hypercapnia somewhat suppressed regional hyperoxic vasodilation and/or recruitment of the pulmonary vascular beds, whereas in the reimplanted lung lobe it potentiated the hyperoxic pulmonary vascular response. The alveolar oxygen tension seems to be the main factor in the regulation of regional perfusion in the lungs.

Animals↗
PubMed1979

Bronchogenic carcinoma producing ectopic steroid hormones.

A patient with steroid hormones or androgen producing bronchogenic adenocarcinoma was presented. Clinically he had a mediastinal mass and bilateral multiple pulmonary nodules which showed a rapid growth despite cancer chemotherapy. At postmortem examination, radioimmunoassay of the tumor tissue revealed androgen and their precursors. The mitochondria of the tumor cells resembled those of cells in the zona reticularis of the adrenal cortex.

Adult↗
PubMed1979

Effect of aminophylline on regional perfusion distribution in the lungs.

Using ten normal dogs, the right upper lobe of the lung was isolated in vivo by a balloon catheter and was artificially ventilated with nitrogen, air, 60% oxygen in nitrogen, and 60% oxygen and 20% carbon dioxide in nitrogen, while the rest of the lungs maintained a spontaneous breathing of ambient air. Aminophylline did not show a vasodilating action under severe alveolar hypoxia (PAO2: ca. 40 mmHg); on the contrary, it seemed to potentiate hypoxic pulmonary vasoconstriction. When the regional alveolar oxygen tension became less hypoxic (PAO2: ca. 70 mmHg) or higher than that in the rest of the lungs which spontaneously breathed ambient air, aminophylline showed a definite vasodilating action. Aminophylline also showed a vasodilating action in alveolar hypercapnia in the presence of alveolar hyperoxia.

Aminophylline↗
PubMed1978

Regulation of regional perfusion distribution in the lungs. Experimental model and effect of alveolar pressure.

An experimental model for studying changes in regional perfusion distribution in the lungs of a dog was described. The right upper lobe was separated in vivo from the rest of the lungs by a balloon catheter and gas exchange of the lobe was artificially done asynchronously with the rest of the lungs by using a gas of interest at a prescheduled aveolar pressure. 99mTc-albumin microsphere was the agent of choice for multiple sequential studies in one dog. Alveolar gas composition reached a plateau after the 4th inflation of the right upper lobe. Effect of alveolar pressure on regional perfusion distribution was studied by using nitrogen and air as exchange gases. Perfusion distribution in the right upper lobe was the least at the maximal alveolar pressure of 14 to 19 cm H2O, while it was the greatest at the tidal maximal alveolar pressure of 1 to-1cm H2O with either gas. Alveolar hyperinflation in a localized lung region due to the increase in regional alveolar pressure reduced regional perfusion distribution.

Air↗
PubMed1976

Indication of mediastinal lymph nodes metastases by radioaerosol inhalation lung scanning in pulmonary neoplasm.

Fifty-three patients with pulmonary neoplasm were studied by radioaerosol inhalation and perfusion lung scans, bronchoscopy and spirometry. The probability of lymph node metastases could be estimated by the amount of inhaled aerosol deposited at the carina. On thoracotomy, actual mediastinal lymphadenopathy was minimum, if any, in 4 patients without carinal aerosol deposition. Application of the aerosol inhalation lung scan to pulmonary neoplasm provides useful diagnostic and prognostic information regarding mediastinal lymph nodes metastases.

Adult↗