We investigated pulmonary microembolism (PME) produced in mongrel dogs (10-15kg) by barium sulfate (BaSO₄). These studies were attempted to clarify the regulatory mechanisms of vasoactive substances (histamine, serotonin and prostaglandins), and the effect of platelet aggregation on the PME-induced changes of pulmonary arterial pressure (P_PA) or pulmonary perfusion pressure (PPP).
The results obtained were as follows;
In rive:
1) Infusion of 30mg/kg of BaSO₄ suspension in saline (30%, 0.1ml/kg) into the right ventricle caused rapid increase of P_PA, which rose to a maximum (P_PA-max) after 10-20 seconds and returned gradually to the original level (baseline). The ratios of P_PA-max to the baseline obtained by repeated embolizations were almost linearly elevated (control study). The oxygen pressure of the femoral artery following embolization decreased to the minimum value after 30-40 seconds and rather promptly returned to the original value.
2) The embolism-induced changes of P_PA under minimal administration of heparin (no more than 500 units total dose) was significantly enhanced as compared with a control study under sufficient heparinization (800-1000units/kg).
In the excised lower lung lobe:
3) Barium sulfate suspension in saline (10%, 0.05ml/kg) was infused in the excised left lower lung lobe under constant perfusion (130-170ml/min) with autologous blood. After repeated injections of 5mg/kg (10%, 0.05ml/kg) of BaSO₄ into the circuit, the pulmonary perfusion pressure (PPP) rapidly rose to the peak value (PPP-max). The ratio of PPP-max to the haseline just prior to each embolization was almost constant (150%) (control study). The administration of anti-histamine (mepyramine maleate, 100μg/ml) and anti-sorotonin (methysergide: 100μg/ml, cyproheptadine: 30μg/ml) into the reservoir significantly inhibited the embolism- induced elevation of PPP.
4) By adding aspirin (1mg/ml) into the reservoir the PME-induced elevation of PPP increased significantly, as compared with control studies.
5) The same experimental procedures were done in thrombocytopenia by using anti-canine platelet rabbit antibody. Aspirin administration also enhanced the elevation of PPP induced by PME.
These results suggest that prostaglandins as well as histamine and/or serotonin may play important roles in acute changes of PPP, and that acute pulmonary hypertension may be attenuated by endogenous vasodilator prostaglandins in the lung or the pulmonary capillaries, since PME-induced elevation of PPP was enhanced by aspirin which is a biosynthesis inhibitor of prostaglandins.

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The ultrastructure of the bronchial wall nerve fibers was studied in 4 asthmatics and 3 other cases of pulmonary diseases (sclerodermia with chronic bronchitis, pulmonary emphysema with cor pulmonale and idiopathic pulmonary hemosiderosis).
The biopsy specimens were obtained from lobular bronchial wall, using a flexible bronchofiberscope, except for two autopsy specimens obtained from cases which died from suffocation.
Vacuolar changes were found in the axons of the myelinated nerve fibers but the myeline sheated and the Schwann cells showed no remarkable changes. Further, the unmyelinaled nerve fibers were normal. The rate of vacuolar changes in the axons was 17/96 17.7%.
These vacuolar changes of the axons of myelinated fibers were obtained at a higher rate in asthmatics (average 30.6%) than in other pulmonary diseases (4.2%), and it is noteworthy that it was the asthma cases which suffocated.

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Twelve patients with cryptogenic fibrosing alveolitis were evaluated by computer tomography (CT). The review of the clinical features suggested that the durations of the disease were relatively long for all patients. Studies were made on the CT images displayed mostly with a window level of -350 and window width of 400, but occasionally with other conditions whenever necessary (settled attenuation values of water and air, 0 and -500, respectively).
In the control study, the densities of the lung fields were nearly homogeneous on the CT images. Pulmonary blood vessels radiated out from the hilum. They tapered and disappeared in the most peripheral areas and did not reach the inner surfaces of the chest wall which, except for the lung apices, was smooth and distinct on the CT images.
The most frequently observed findings in the diseased lungs were the crowds of fine nodules of different sizes and homogeneous features with low density suggesting relatively early changes of the disease and fine rings suggesting honeycombing. These changes were frequently found together forming a mixed pattern. Fine reticulonodular, fine or coarse reticular lesions and bullae beneath the pleura were infrequent.
Pulmonary blood vessels in the diseased areas were frequently emphasized with increased density and thickness. The vessels with marked increment in thickness were observed occasionally as rod or spindle-like in appearance. The images of the most peripheral vessels were also emphasized and appeared to reach the inner surface of the chest wall. The mechanism of the emphasis of vessels is not clear. However, fibrous thickening of the interstitial tissues surrounding pulmonary arteries and attendant bronchi may be responsible. In addition, the possibility that vessels traversing the diseased areas with decreased air content are exaggerated by the partial volume effect should be taken into consideration.
On most of the slices showing the above-described alterations, more advanced changes were found in the outer, posterior and lower portion than any other field. These changes were unevenly distributed on the CT slices, therefore CT seems to be valuable in detecting their distribution in detail.

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Pulmonary N₂ washouts by either He-O₂ or SF₆-O₂ were observed in 6 healthy laboratory workers and on 10 mongrel dogs. N₂ washout by SF₆-O₂ was consistently faster, especially at the beginning of washout, than that by He-O₂. In a model experiment where N₂ was washed out from 4 anesthesia bags arranged in parallel in a lucite box, N₂ washout by He was a bit faster than that by SF₆.
Washout of He in the bags by air is significantly faster than SF₆ washout by air. All these comparisons were made among the results obtained under approximately identical ventilatory conditions.
The third experiment was conducted to observe any difference in gas penetrations through a bronchial hollow cast of a dog into well-stirred gas phase. SF₆ dispersion into the stirred gas phase was significantly greater than that of He. As duration of inspiration increased, the amount of dispersed gas and the difference between He and SF₆ increased. N₂ dispersion through the hollow cast into well-stirred He was consistently larger than that into SF₆, which was in line with faster He washout by air from the bags.
Thus, the faster N₂ washout by SF₆-O₂ than by He-O₂ in vivo, which might be the reverse to expectation based on molecular diffusion alone, could be attributed mainly to the greater axial penetration of SF₆ and to better convective mixing of SF₆ in the airways during inspiration. A role of molecular diffusion between inspirate and stale gas seems to become more important when alveolar N₂ concentration becomes low during washout and when SF₆ or He in the lungs is washed out by air. Phenomena during expiration require further investigation.

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A 65 year-old male was admitted on September 1, 1977 complaining of edematous erythema, myalgia, swallowing disturbance, productive cough and exertional dyspnea. Physical examination showed widespread poikilodermia, muscle weakness, decreased deep tendon reflex, clubbed fingers, Velcro rales on the back base of chest and no lymphadenopathy. Chest X-ray demonstrated diffuse interstitial infiltrates in lower bases and a large mass in the right lower lobe. Lung function tests showed a restrictive pattern, decreased diffusion capacity and hypoxemia without hypercapnia. Electromyogram showed a myogenic pattern, serum creatinine phosphokinase level was high and urinal excretion of creatine was excessive. Biopsies of skin and muscle revealed typical dermatomyositis. Cytology of sputum was class V and squamous cell carcinoma was suspected. Generalized chemotherapy and corticosteroid administration were performed, which were not effective and the patient expired on the 43rd hospital day.
Autopsy revealed interstitial pneumonia or pulmonary fibrosis with honeycomb appearance in both lungs, especially in the lower lobes, and syncronous multiple lung cancers, squamous cell carcinomas in the right S₁₀ and left S₁₊₂, a poorly differentiated adenocarcinoma in the right S₄ and a small cell carcinoma in the left S₄, which had metastasized to both hilar nodes.

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13才男子中学生. 交通事故直後に, 急激かつ重篤な respiratory distress が発生した. 患者はすぐに意識が消失し, この後一時的な心停止を来たしたが, 蘇生後PEEPを併用した volume-limited veutilator に著効し, わずか1日で weauing が可能であった.
交通事故後急激に発症した呼吸不全は, この臨床経過より neurogenic pulmonary edema と考えられる.

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