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Biomedical subjects

R G Crystal

Publications and source records attributed to R G Crystal.

At least 19 recordsLinked to original sources
PubMed1992

Tumor necrosis factor modulation of expression of the cystic fibrosis transmembrane conductance regulator gene.

Based on the knowledge that expression of the cystic fibrosis transmembrane conductance regulator (CFTR) gene can be modulated at the transcriptional level, and that the CFTR gene promoter contains sequences homologous to elements in other promoters that respond to tumor necrosis factor-alpha (TNF), we evaluated the hypothesis that TNF might modulate CFTR gene expression in epithelial cells. Studies with HT-29 cells, a colon epithelium-derived tumor cell line known to express the CFTR gene, demonstrated that TNF downregulated CFTR mRNA transcript levels in a dose- and time-dependent fashion. Interestingly, nuclear run-on analyses demonstrated that TNF did not affect the rate of transcription of CFTR gene, but exposure of the cells to TNF did modify the stability of CFTR mRNA transcripts, resulting in a mRNA half-life that was reduced to 65% of the resting level. These observations suggest that CFTR gene expression can be modulated by TNF, at least in part, at the posttranscriptional level.

Blotting, Northern↗
PubMed1979

Cigarette smoking induces functional antiprotease deficiency in the lower respiratory tract of humans.

Current concepts of the pathogenesis of emphysema suggest that it results from an imbalance of elastase and antielastase activity within the alveolar structures. Although emphysema that is associated with hereditary deficiency of serum alpha 1-antitrypsin conforms to this scheme, the major risk factor in the more common form of emphysema is cigarette smoking. A study was designed to evaluate the premise that cigarette smoking may be associated with an acquired, functional defect in lung alpha 1-antitrypsin. Determination of the antielastase activity of alpha 1-antitrypsin obtained from the lungs of smoking and nonsmoking individuals revealed a nearly twofold reduction in the functional activity of this elastase inhibitor in the lungs of cigarette smokers. These data suggest that cigarette smokers may lose some of the normal antielastase protective screen of the lower respiratory tract, making them more vulnerable to destructive lung disease.

Adult↗
PubMed1979

Collagenase in the lower respiratory tract of patients with idiopathic pulmonary fibrosis.

To test the hypothesis that idiopathic pulmonary fibrosis (IPF) is mediated through collagenase present in the lower respiratory tract, we used the fiberoptic bronchoscope to obtain fluid from the lower respiratory tract of 24 patients with IPF, 18 controls and nine patients with sarcoidosis. The fluid was analyzed for a variety of enzymes, including collagenase. Fifteen of 21 patients with IPF showed collagenase activity, whereas normal controls and patients with sarcoidosis showed none (P greater than 0.001, for all comparisons). In two patients with IPF who were re-evaluated after eight to 24 months, the collagenase activity was persistent. Fluid from patients with IPF also contained elevated levels of a non-specific neutral protease (P greater than 0.01 compared with controls), but there was no elastase activity in fluid from patients with IPF or from controls. The collagenase found in lavage fluid in IPF cleaved lung collagen into collagenase-specific TCA and TCB fragments. We conclude that in IPF the collagen of the lung is subjected to sustained lysis, followed by disordered resynthesis, and that the presence of active collagenase in the lower respiratory tract is a specific feature of the alveolitis associated with this disease.

Adult↗
PubMed1979

Localization of the immune response in sarcoidosis.

Pulmonary sarcoidosis is an interstitial disease characterized by granulomas within the lung parenchyma, anergy to a variety of skin tests, and decreased numbers of circulating T-lymphocytes. To evaluate the effector cell populations present at sites of disease in patients with active pulmonary sarcoidosis, inflammatory and immune effector cells were isolated from lung via bronchoalveolar lavage and compared to comparable cell populations from the peripheral blood of the same patients and similar cell populations of normal subjects and patients with idiopathic pulmonary fibrosis. Patients with sarcoidosis had a marked increase in the percentage of T-lymphocytes in the lung despite a significant peripheral blood T-lymphocytopenia. In addition, many of these T-lymphocytes demonstrated surface marker characteristics associated with lymphocyte activation, and they spontaneously secreted leukocyte inhibitory factor. In contrast to patients with sarcoidosis, normal subjects and patients with idiopathic pulmonary fibrosis had similar percentages of T-lymphocytes in lung and blood, and there was no evidence for T-lymphocyte activation. Analysis of lymphocytes in uninvolved marrow from 7 of 8 patients with sarcoidosis revealed proportions of T-lymphocytes similar to those in the marrows of normal subjects and patients with idiopathic pulmonary fibrosis. In comparison, one patient with sarcoidosis had large numbers of T-lymphocytes in bone marrow, but only in areas where there were granulomas in the marrow. These studies suggest that: (1) the alveolitis of pulmonary sarcoidosis is characterized by large numbers of activated T-lymphocytes, and (2) there is an anatomic localization of the immune response in sarcoidosis in that analysis of uninvolved tissues such as peripheral blood may not reflect local immune responses at sites of granuloma formation.

Adult↗
PubMed1979

Anchoring fibrils in the normal canine respiratory system.

Electron microscopic study of the normal canine respiratory tree disclosed the presence of anchoring fibrils, a distinct class of fibrils of extracellular connective tissue, in association with the following types of cells: (1) basal cells and special type cells of trachea and bronchi; (2) ciliated cells and basal cells of bronchioles; (3) ductal cells, secretory cells, and myoepithelial cells of tracheobronchial glands. Anchoring fibrils in the normal respiratory system measured up to 6,000 A in length and from 170 to 400 A in thickness, and had a banding pattern that differed from that of collagen fibrils and connective tissue microfibrils. They formed arcs, the ends of which inserted into the basal lamina underlying the basal portions of the cells, often in the vicinity of hemidesmosomes. Anchoring fibrils decreased in number and size in the more distal portions of the respiratory tree, and were not found in alveolar septums. Anchoring fibrils in lung appeared similar to those described in other organs, but were often small and inconspicuous. The function of these structures is to reinforce the attachment of the epithelial basal lamina to the underlying connective tissues.

Animals↗
PubMed1979

Bleomycin-induced interstitial pulmonary disease in the nude, athymic mouse.

Evidence from divergent sources suggests that some forms of interstitial pulmonary disease are associated with abnormalities of the cellular immune system. To evaluate whether cellular immune processes are necessary determinants for the development of parenchymal alveolitis and fibrosis secondary to bleomycin, we examined the effect of bleomycin on the NIH, outbred white mouse as compared to the homozygous nude, athymic mouse on the NIH outbred background. The nude mouse has virtually no detectable cell-mediated immune function; we therefore hypothesized that if this component of the immune system were necessary for the development of bleomycin-induced interstitial disease, bleomycin would not induce the same pulmonary lesion in the nude mouse as in the white mouse. However, both white and nude mice developed alveolitis and fibrosis after intraperitoneal administration of bleomycin. Comparison of the frequency and severity of these lesions in the 2 groups revealed no significant differences. These findings suggest that the presence of an intact cell-mediated immune system is not an absolute requirement for the development of bleomycin-induced interstitial disease in the mouse. To the extent that this model is an appropriate approximation of human bleomycin-induced pulmonary disease, these results are consistent with the hypothesis that T-lymphocyte mediated processes are not primary determinants of this lesion.

Animals↗
PubMed1979

Acute hypersensitivity pneumonitis: serial changes in lung lymphocyte subopulations after exposure to antigen.

The earliest lesion in hypersensitivity penumonitis is an acute inflammatory alveolitis characterized by parenchymal hemorrhage and accumulations of polymorphonuclear leukocytes within the lung. In many instances, this initial lesion is replaced by a more chronic alveolitis, with development of mononuclear cell interstitial infiltrate, granuloma formation, and interstitial fibrosis. To help define the mechanisms by which the early polymorphonuclear leukocyte alveolitis of acute hypersensitivity pneumonitis evolves into a chronic mononuclear-cell process, an animal model of the disease was developed using guinea pigs sensitized by footpad injeection with either ovalbumin (OVA) in complete Freund's adjuvant (CFA), CFA alone, or phosphate-buffered saline. Ten days after sensitization, the animals were challenged by intratracheal injection of either particulate OVA, particulate human serum albumin, or phosphate-buffered saline alone, and their lungs were evaluated sequentially for changes in histologic appearance and lymphocyte subpopulations. After challenge, only animals sensitized with CFA plus OVA and challenged with particulate OVA developed pulmonary lesions consistent with acute hypersensitivity pneumonitis. Within 4 h after challenge, these animals developed an acute hemorrhagic alveolitis that persisted for more than 24 h. By 48 to 96 h, the alveolitis evolved into a predominantly mononuclear-cell infiltrate. This change in the histologic appearance of the lungs in these animals was preceded by a rapid increase in the proportions of T-lymphocytes within the lungs, noted by 24 h after intratracheal challenge with specific antigen. Before intratracheal challenge with antigen, lung lymphocytes from only the group of animals immunized with CFA plus OVA were capable of proliferating on exposure to OVA in vitro. In the same group, lymphocytes recovered from the lung after intratracheal particulate OVA demonstrated blast transformation in vivo, a phenomenon not found in any other group. These studies suggest that the alveolitis of acute hypersensitivity pneumonitis is rapidly associated with changes in populations of immune effector cells before development of the mononuclear cell alveolitis characteristic of the chronic disease.

Alveolitis, Extrinsic Allergic↗
PubMed1979

Morphologic-physiologic correlates of the severity of fibrosis and degree of cellularity in idiopathic pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a progressive disease of lung parenchyma characterized by a chronic inflammatory cellular infiltration and varying degrees of interstitial fibrosis. Current data indicate that the severity of fibrosis and the degree of cellularity determine, in part, the prognosis of IPF and the response to therapy. Whereas lung biopsy gives the best assessement of fibrosis and cellularity, physiologic studies are used to stage and monitor the disease process. To determine which physiologic studies correlate best with severity of fibrosis and degree of cellularity, these parameters were graded in lung biopsies of 23 patients with IPF and compared with a variety of physiologic studies. Although vital capacity, total lung capacity, and diffusing capacity are commonly used as objective monitors of the disease process, none of these parameters correlated with either the severity of fibrosis or the degree of cellularity in biopsy specimens. In contrast, almost all parameters of lung distensibility correlated with the morphologic assessment of degree of fibrosis; compliance had the best correlation. Parameters of distensibility, however, correlated poorly with the degree of cellularity. In comparison, gas exchange during exercise correlated with both morphologic parameters; the exercise-induced changes in arterial oxygen pressure per liter of oxygen consumed had a high correlation with the degree of fibrosis (r = 0.89; P less than 0.001) and correlated to a lesser extent with the degree of cellularity (r = 0.56; P = 0.009). In contrast, neither the resting arterial oxygen tension nor the arterial oxygen tension at maximal exercise correlated with the morphologic assessment of degree of fibrosis or the degree of cellularity. These morphologic-physiologic comparisons suggest that (a) lung volumes and diffusing capacity are poor monitors of both the degree of fibrosis and the degree of cellularity; (b) the fibrotic process contributes, at least in part, to parameters of lung distensibility, and both fibrosis and cellularity contribute to gas exchange alterations during exercise; and (c) parameters of lung distensibility and exercise-induced gas exchange alterations may be useful in staging the severity of disease in IPF.

Adult↗
PubMed1979

Nuclear inclusions in alveolar epithelium of patients with fibrotic lung disorders.

Ultrastructural study of pulmonary biopsy specimens from patients with fibrotic lung disease disclosed the presence of nuclear inclusions in 1% or less of cuboidal alveolar epithelial cells in 9 of 19 patients, including 6 of 12 patients with idiopathic pulmonary fibrosis, 2 of 3 patients with collagen-vascular disease, and 1 of 3 patients with sarcoidosis. Nuclear inclusions were not observed by ultrastructural study in 5 control patients. The inclusions consisted of masses or aggregates of tubules which probably were derived from the inner nuclear membranes. These tubules were smooth-walled, showed branchings and bifurcations, were composed of single trilaminar membranes, usually had a clear content, and ranged from 500 to 1000 A in diameter. They resembled nuclear tubules which occur in other cell types under conditions of rapid growth or specific hormonal stimulation. Statistically significant differences between the groups of patients with and without nuclear inclusions in cuboidal alveolar epithelial cells were not found with respect to smoking history, degree of fibrosis in the lung biopsy specimen, or the degree of pulmonary physiologic impairment. However, the average age of the patients having nuclear inclusions was significantly greater than that of patients not having nuclear inclusions. In addition, the frequency of indentations in the nuclei of cuboidal alveolar epithelial cells was greater in patients with nuclear inclusions than in patients without nuclear inclusions. Highly significant correlations were observed between the presence of nuclear inclusions and the presence of a) anchoring fibrils and hemidesmosomes along the basal surfaces of alveolar epithelial cells and b) multilayering of the alveolar epithelium.

Aging↗
PubMed1979

Ultrastructure of pulmonary mast cells in patients with fibrotic lung disorders.

The topographic distribution, population density, and ultrastructural features of metachromatic cells (mast cells and basophilic leukocytes) were studied in lung biopsies from five control patients and 17 patients with fibrotic lung disorders. The great majority of metachromatic cells were mast cells. The average number of metachromatic cells per square millimeter of tissue section was much larger in patients with fibrotic lung disorders (45.8 +/- 6.5) than in control patients (2.6 +/- 1.6). In control patients, mast cells were most frequently seen in subpleural and perivascular connective tissue. In contrast, the vast majority of mast cells in patients with fibrotic lung disorders was present in thickened, fibrous alveolar septa; mast cells also were found within the alveolar epithelial layer and alveolar lumina. The quantitative distribution of different types of mast cell granules differed in the two groups of patients: granules composed of scrolls were more frequent in control patients, and granules of the combined type (containing mixtures of different components within the same granule) were more frequent in patients with fibrotic lung disorders. Mast cells in the latter patients appeared to migrate through defects in the basement membrane into the epithelial layer and alveolar lumina; mast cells in these areas often showed reduced numbers of granules and disorganized granule content. These changes suggest that pulmonary parenchymal mast cells in fibrotic lung disorders undergo a chronic process of partial degranulation which differs from that found in anaphylaxis; this chronic release of mast cell products may contribute to the continuing alveolar injury and the ventilation-perfusion inequalities observed in the fibrotic lung disorders.

Adult↗
PubMed1979

Inflammatory and immune processes in the human lung in health and disease: evaluation by bronchoalveolar lavage.

Bronchoalveolar lavage is an invaluable means of accurately evaluating the inflammatory and immune processes of the human lung. Although lavage recovers only those cells and proteins present on the epithelial surface of the lower respiratory tract, comparison with open lung biopsies shows that these constituents are representative of the inflammatory and immune systems of the alveolar structures. With the use of these techniques, sufficient materials are obtained from normal individuals to allow characterization of not only the types of cells and proteins present but their functions as well. Such observations have been useful in defining the inflammatory and immune capabilities of the normal lung and provide a basis for the study of lung disease. Lavage methods have been used to characterize inflammatory and immune processes of the lower respiratory tract in destructive, infectious, neoplastic, and interstitial disorders. From the data already acquired, it is apparent that bronchoalveolar lavage will yield major insights into the pathogenesis, staging, and therapy decisions involved in these disorders. (Am J Pathol 97:149--206, 1979).

Bacterial Infections↗