摘要:

The interaction between the number ofβadrenergic binding sites and the ability of aβadrenergic agonist, isoproterenol, to increase cyclic AMP content of guinea pig lung slices was studied. A complex relationship was found. Chronic sensitization of the guinea pig to an aerosol of ovalbumin resulted in lung slices which were hyporesponsive to isoproterenol in vitro, yet possessed an unchanged number of beta adrenergic binding sites. Chronic exposure of guinea pigs to aerosoled isoproterenol or acute treatment with hydrocortisone did not change the number ofβadrenergic binding sites or the responsiveness of the tissue to isoproterenol in vitro. However, chronic hydrocortisone treatment increased the number of binding sites found on the lung slices by 44%, yet there was no change in the responsiveness of the tissue to isoproterenol in vitro. These data suggest that drugs and disease may change the relationship between the various components of theβadrenergic binding - adenylate cyclase complex of lung.

ISSN:0190-2148    

DOI:10.3109/01902148109052297

出版商:Taylor&Francis    

年代:1981

数据来源: Taylor

摘要:

Optimal conditions in vitro were established for the assay of phospholipases A of Bacillus Calmette Guerin-induced alveolar macrophages that deacylated dipalmitoyllecithin in the alkaline pH range. Sodium deoxycholate and Ca++were found to stimulate both phospholipases A1and A2, whereas sodium dodecylsulfate strongly inhibited both enzyme activities. Other detergents like Triton X-100, Triton WR-1339, and Tween-20 activated phospholipase A1, whereas they had no effect on or slightly inhibited the phospholipase A2enzyme. These phospholipases preferentially removed palmitic acid regardless of the position of palmitic acid on the phospholipid molecule and were more active on phosphatidylcholines than phosphatidylethanolamines. This suggests a role for macrophage phospholipases A in the clearance of saturated lecithins in the pulmonary surfactant complex.

ISSN:0190-2148    

DOI:10.3109/01902148109052298

出版商:Taylor&Francis    

年代:1981

数据来源: Taylor

摘要:

In order to demonstrate the role of lipid-linked sugars as intermediates in the synthesis of pulmonary glycoproteins, membranous preparations of rabbit lung were incubated with GDP-14C-mannose and selectively extracted with chloroform-methanol (2:1) and chloroform-methanol-water (1:1.03). The chloroform-methanol extract was found to contain a lipid-linked sugar which had chemical and chromatographic properties similar to mannosyl-phosphoryl dolichol. The chloroform-methanol-water extract contained an oligosaccharide- lipid and the remaining precipitate contained a labeled protein. Transfer of mannose from the labeled mannolipid to the endogenous protein was demonstrated. These studies indicate a glycolipid intermediate is present in the synthesis of oligosaccharides attached to pulmonary glycoproteins.

ISSN:0190-2148    

DOI:10.3109/01902148109052299

出版商:Taylor&Francis    

年代:1981

数据来源: Taylor

摘要:

A relatively inexpensive method for the noninvasive in vivo detection of ferrimagnetic particles within the lungs of a large laboratory animal, viz., the donkey, is described. The particles were neutron activated prior to inhalation, which permitted a comparison of two different retention measurements for the same particles, i.e., a well-characterized radiological-detection method concurrent with the newer magnetic-field technique. The long-term clearance of the particles from the lung was monitored in terms of the reduction in initial remanent field following magnetization, and the reduction inγ-ray flux reaching the collimated scintillation detectors. Comparison of the measurements confirmed that the reduction of the initial remanent-field values with time was due to particle clearance rather than a change of the iron state to a nonmagnetic form. This validates previous reports that particle clearance studies can be performed using remanent magnetic-field measurement techniques. However, remanent magnetic-field measurements require careful design and interpretation, since they are highly sensitive to the distribution of the particles within the effective viewing field.

ISSN:0190-2148    

DOI:10.3109/01902148109052300

出版商:Taylor&Francis    

年代:1981

数据来源: Taylor

摘要:

Plasma fatty acids represent major precursors of lung lipids. In this study, the pathways of palmitate metabolism were measured in an isolated perfused rat lung. Lungs were ventilated with 5% CO2in air and perfused with Krebs-Ringer bicarbonate containing 3% serum albumin and 0.25 mM [U-14C] and [9, 10-3H] palmitate. Fatty acid utilization was estimated by recovery of radiolabel in products of metabolism. Fourteen percent of a total14C - fatty-acid utilization of 4.5μmol fatty acid/100 min/g dry wt. was recovered as14CO2- Degradation of fatty acid to acetyl CoA was indicated by a3H2O production that was twice fatty acid oxidation to CO2. The majority of palmitate was recovered in lung phosphatidylcholines with al4C to3H ratio of 1.4 accounting for differences between,14CO2and3H2O productions. Addition of glucose to the perfusate decreased fatty acid oxidation to CO2by 32% but had no effect on14C recovery in phospholipids. Perfusion with the uncoupler of oxidative phosphorylation 2,4-dinitrophenol stimulated fatty acid oxidation twofold but decreased14C incorporation into lipids. These data together with estimates of fatty acid synthesis based on3H2O incorporation into lipids, suggested that exogenous fatty acids and glucose both represent sources of carbon for de novo fatty acid synthesis and energy production.

ISSN:0190-2148    

DOI:10.3109/01902148109052301

出版商:Taylor&Francis    

年代:1981

数据来源: Taylor

摘要:

The frequency and types of abnormal cilia prior to and following nitrogen dioxide (NO2) exposure in the small airways of an inbred strain of mice was quantitated by transmission electron microscopy. Age-matched male and female mice were exposed ta 20 ppm NO2for 28 days. In both sexes, exposures to NO2resulted in a significant increase (P<0.01) in abnormal cilia characterized by (1) decreased number of ciliary structures on cell surface, (2) focal swelling of the cytoplasmic matrix of the ciliary shaft, and (3) occasional compound cilium. The basal bodies of the ciliated cells from which atypical cilia arose appeared normal. In mice killed 30 days after termination of NO2exposure, the ciliary morphology returned to normal and the incidence of abnormal cilia decreased to levels observed in controls. These observations indicate that subacute exposure to NO2causes injury to the ciliary shaft; these changes are reversible within 30 days following removal from NO2.

ISSN:0190-2148    

DOI:10.3109/01902148109052302

出版商:Taylor&Francis    

年代:1981

数据来源: Taylor

摘要:

Rats chronically treated with the cationic amphipilic drug iprindole developed a phospholipid storage disorder in their pulmonary alveolar macrophages (AMs). AMs from these iprindole-treated rats (IP-AMs) were compared to AMs from control rats (C-AMs) regarding oxygen consumption and the release of two reactive oxygen species, superoxide anion and hydrogen peroxide. Responses of C-AMs and IP-AMs were compared at rest and when stimulated by unopsonized or opsonized zymosan. Opsonization was not necessary in order to induce respiratory burst-associated phenomena in either cell type; in fact in all cases, for a given cell type responses to unopsonized zymosan were virtually identical to those of opsonized zymosan. When at rest, IP-AMs consumed oxygen at a rate nearly identical to that of C-AMs. When stimulated with zymosan particles, IP-AMs consumed more oxygen than controls. However, when superoxide anion and hydrogen peroxide, two products of the respiratory burst were measured, IP-AMs released less of these species than C-AMs when at rest and when particle stimulated. Despite the lower total release of these species by the IP-AMs, the zymosan-induced release (stimulated minus resting levels) was greater for these cells than C-AMs. Therefore, the IP-AMs were found to be more responsive to the zymosan particle than C-AMs. The results indicate marked changes in the release of reactive oxygen species from the AMs following induction of phospholipidosis.

ISSN:0190-2148    

DOI:10.3109/01902148109052303

出版商:Taylor&Francis    

年代:1981

数据来源: Taylor