Expired Gas Analyzer (Sanei Sokki), which can perform a rapid and continuous recording of the expired gas oxygen concentration, was used for the measurement of “closing volume”. Briefly, the test was done in the following way. Starting from the RV level, the subject breathes at first a bolus of helium (about 300ml), then pure oxygen to the TLC level, after which he expires slowly and steadily (about 200-300ml/sec.) into the circuit. Both expired gas oxygen concentration and volume are recorded and displayed on a storage oscilloscope (Tektronix). Toward the end of the expiration the oxygen concentration drops with the increase of helium mixing in the expired gas, thus forming “Phase IV”. Closing volume (CV), which is defined as the volume between the onset of phase IV and RV, was expressed as a percentage of vital capacity (CV/VC%).
Using this method, CV/VC% was measured in 75 subjects, Thirty-one were normal, nine had chronic obstructive lung disease (emphysema and chronic bronchitis), nineteen had bronchial asthma, and sixteen had various lung diseases including eight cases of heavy smokers.
As reported by others, there was a positive correlation between age and CV/VC% for both normal males and females.
In patients with chronic obstructive lung disease and bronchial asthma, who showed a significant degree of airway obstruction, the slope of the alveolar plateau (phase III) was steep and CV/VC% was increased in most of the cases.
In patients with asymptomatic asthma, whose spirometric studies were either normal or only slightly impaired, the slope of the alveolar plateau was not steep but cardiac oscillations, which were clearly observed in normal subjects, were either absent or insignificant. CV/VC% was increased in three and normal in one, however, there were four patients whose closing volume was unobtainable because of the absence of phase IV.
In all of the heavy smokers, CV/VC% was increased.
It is concluded from these results that our method is applicable for clinical purposes.

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Closing volumes were studied to assess it's clinical application.
Firstly, physiologicalfactorsinfluencing closing volumes were examined in ten healthy subjects by measuring simultaneous expired volume-concentration curves of N₂ with two of Ar, He, or SF₆. There were no differences in closing volumes measured by Ar, He, or SF₆bolus. Although there existed a bolus volume at which the onset of phase IV was not detected but identified by resident N₂ method, closing volumes decreased as bol us volume is increased. Furthermore, the closing volumes measured by bolus volume of 15% VC was consistently larger than that measured simultaneously by resident-N₂ method.
We found that a expired flow rate above 0.5l/sec could obscure a clear onset of phase 4, and that any marked changes in flow rate above 0.5l/sec would alter the gas concentrations. For clinical applications, then, we propose that the expiratory flow rate be kept constant and less than 0.5l/sec.
Secondly, the relationships between closing volumes andother lung function parameters were studied in ten healthy subjects and thirteen patients. Most of parameters relating to airway obstructive changes were correlated with closing volumes and closing capacities. Parameters with |r|∨0.5 are listed below.
CC% correlated with FEV₁% (r=-0.77), V₂₅(-0.76), V₅₀(-0.67), R_L(+.66), RV% Pa_O2(-0.54). CV% correlated with V₂₅(r=-0.51) 1nd RV% (+0.53).
Finally, in 282 pupils aged from 7 to 15, CV% was measured together with FEVand the V-V curve to assess it's suitability for mass screening. The subjects two different groups. One was the Onahama group who lived in an industrial area andhad respiratory symptoms, the other wasrthe Uchigo control group who lived in a non-industral town and were selected at random to fit the Ohahama population.
In both groups. the incidence of abnormal CV% was higher than the incidence of abnormal FEV₁%. Between the two groups there was no difference in the percentage of abnormal FEV₁%. However, the Onahama group showed a significantly higher percentage of abnormal CV% than than the Uchigo group (p<0.01).
This suggests that closing volume measurements might be suitable for mass screening for early small airway obstruction.

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Because of sudden loss of consciousness, a eighty-one year old female was admitted to our hospital. No special findings suggestive of Sarcoidosis were obtained from either personal history, physical examination or laboratory studies including chest X-ray examination. On fourteenth hospital day, the patient died of pneumonia. On autopsy, diffusely disseminated sarcoid granulomas throughout many organs were revealed: the lungs, heart, liver, spleen, kidneys and the lymphnodes in bilateral pulmonary hila, paratracheal regions and along abdominal aorta. The granulomas detected in the pulmonary interstitium and peribronchial tissue were accompanied with the Langhans giant cells, but with scant epithelioid cells and lymphocytes. On the other hand, in the granulomas especially in the lymphnodes and the spleen, abundant proliferation of asteroid bodies, giant cells and epithelioid cells were observed. Despite of the lesions in the epicardium and myocardium, no arrhythmia was observed on EGG. Though the characteristic feature of multiorgan involvement in sarcoidosis was still revealed in such a aged patient, the lesions were histologically uneven throughout the organs involved.

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A case of binign neurofibroma of the visceral pleura which is exceedingly rare in the literature, is presented.
A 26 year-old female was admitted to our hospital witha localized homogenous shadow in the right apex on chest X-ray films, which had been suspected, in another hospital, of empyema.
On exploratory thoracotomy in our hospital, a solid tumor, 10×6×3cm in size, was found in the right upper pleural cavity. It was connected through a pedicle to the top of right upper lobe of the lung. Histologically the tumor was a binign neurofibroma.

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