Proteolytic activity (PA) of lung extracts was measured in control hamsters and in those exposed to 20 ppm NO2 for 24 hours (acute) and 30 days (chronic). Total PA of these lungs as measured by pH 7.4 caseinolysis was slightly increased after the 24-hour, but normal following the 30-day exposure. Lung extract fractions from NO2-exposed animals display an increased PA at pH 3.0 and 9.0, but are near control levels at pH 7.0. Serum protease inhibitor (PI) activity is significantly increased after short NO2 exposure as compared with control conditions. No significant increase is observed in PI after chronic exposure. Increase in 24-hr NO2 lung extract PA is associated with increase in PI, which may neutralize the augmented proteolysis. These studies are consistent with previous observations that indicate prolonged NO2 exposure does not produce significant emphysema in the hamster lung.

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PubMedDate not supplied

Effects of nitrogen dioxide on elastin and collagen contents of lung.

Male Syrian hamsters were exposed to 30 +/- 5 ppm nitrogen dioxide for 22 hr daily for 3 wk. Nitrogen dioxide-exposed hamsters sacrificed at various times during the 3 wk exposure showed a general loss of body weight and an increased dry lung weight when compared with the controls, which were housed in a similar, but nitrogen dioxide-free environment. Analysis of total lung collagen and total lung elastin revealed a net decrease in the moieties within 4 and 10 days, respectively, following commencement of nitrogen dioxide exposure. Total lung collagen returned toward pre-exposure levels by the 14th day of nitrogen dioxide exposure. Total lung elastin did not return toward normal until termination of nitrogen dioxide exposure. Recovery in room air for 3 wk following 21 days of nitrogen dioxide exposure restored the total pulmonary collagen and elastin to valutin and collagen degradation and synthesis differ during and after nitrogen dioxide exposure. Lung collagen loss was observed earlier and was restored to normal values during the continuation of nitrogen dioxide exposure. Lung elastin loss occurred later and persisted during the entire period of exposure but returned to normal after exposure was terminated.

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PubMedDate not supplied

The effects of continuous high level nitrogen dioxide on hamsters.

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Animals↗

PubMedDate not supplied

Malignant retroperitoneal paraganglioma: unusual light and electron microscopic findings.

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Aged↗

PubMedDate not supplied

Pulmonary tumorlets in cases of "tuberculoma" of the lung with malignant cells in brush biopsy.

Two cases of pulmonary nodules associated with Mycobacterium intracellulare infection were initially interpreted as carcinomas of the lung after brush cytology specimens were reported to contain malignant epithelial cells. In both instances, the cells observed in the cytology specimens exhibited marked cytologic atypia. These cells were identical to those present in tumorlets adjacent to the granulomatous lesion. Tumorlets may thus represent a source of false-positive cytologic findings or constitute a type of microscopic neoplasms of the lung.

Aged↗