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Biomedical subjects

G M Turino

Publications and source records attributed to G M Turino.

At least 19 recordsLinked to original sources
PubMed1991

Early changes in lung tissue hyaluronan (hyaluronic acid) and hyaluronidase in bleomycin-induced alveolitis in hamsters.

Intratracheal instillation of bleomycin in hamsters initiates a series of events that mimic human interstitial pulmonary fibrosis. Because glycosaminoglycans and particularly hyaluronan (hyaluronic acid, HA), may play an important role in the extracellular matrix response to early injury and subsequent fibrosis, this study was undertaken to define the early time course of changes in HA and hyaluronidase. Hamsters were given either 1 unit bleomycin sulfate in 0.2 ml saline or 0.2 ml saline (control), and randomly selected animals from both groups were killed at Days 3, 5, 6, 7, 9, and 17. Glycosaminoglycan fractions prepared from lung tissue of individual animals were analyzed for HA. The maximal HA content was reached 6 days after instillation of bleomycin and was 14.6-fold the normal value. The weight of injured lungs was 2.3-fold the control value. Thus, the increase in HA content was 30-fold. By Day 7 the HA content had dropped sharply. It then declined gradually to approximately double control values at Day 17. The specific activity of lysosomal hyaluronidase was the same in bleomycin-treated lungs and control lungs. Total units of the enzyme were increased in injured lungs, even at the time of maximal HA content, indicating active turnover of HA. The maximal HA content occurs prior to the rise in collagen and elastin biosynthesis. This observation in addition to the magnitude of the increase and its abrupt decline suggest that HA may be an important initiating factor for pathologic changes in lung extracellular matrix components.

Animals↗
PubMed1990

The effect of 60% oxygen on air-space enlargement and cross-linked elastin synthesis in hamsters with elastase-induced emphysema.

Hyperoxia is routinely administered to patients with severe emphysema. To gain insight into the possibly adverse effects of such treatment, hamsters were exposed to 60% oxygen for 5 days, beginning 48 h after induction of pulmonary emphysema by intratracheal instillment of pancreatic elastase. Control groups consisted of (1) animals instilled with elastase and exposed to room air, (2) animals instilled with saline and exposed to 60% oxygen, and (3) animals instilled with saline and exposed to room air. Cross-linked elastin content and synthesis in the lung were measured immediately following termination of hyperoxia, and the mean linear intercept was determined 4 wk later. Cytologic examination of bronchoalveolar lavage fluids was also performed. Statistical significance was determined by a two-way analysis of variance. Results indicate that exposure to 60% oxygen significantly affected (p less than 0.05) air-space size, causing a 51% increase among elastase-treated hamsters (124 versus 82 microns) but only a 4% increment among saline-treated animals (52 versus 50 microns). When compared to other groups, animals treated with both elastase and hyperoxia had a significantly greater (p less than 0.01) percentage of neutrophils (28%) in their lung lavage fluids immediately following exposure to 60% oxygen. Although total lung elastin content was not altered by hyperoxia at this time, labelling of elastin cross-links was significantly increased (p less than 0.05). These studies demonstrate that exposure to 60% oxygen enhances elastase-induced lung injury. They also raise the possibility that oxygen therapy may, under certain circumstances, accelerate the progression of human emphysema.

Animals↗
PubMed1987

Increased synthesis of elastin in amiodarone-induced pulmonary fibrosis.

Both synthesis and total content of lung elastin were measured after induction of interstitial pulmonary fibrosis in hamsters by a single intratracheal insufflation of amiodarone. Elastin synthesis, as measured by 14C-lysine incorporation into desmosine and isodesmosine, was significantly elevated (P less than 0.05) above control values for a 3-week interval after induction of lung injury. Total lung elastin content in the amiodarone-treated animals was 32% greater than in controls (P less than 0.05) 2 weeks after insufflation of the agent. Furthermore, the time course of elastin synthesis in this experimental model was similar to that observed in bleomycin-induced pulmonary fibrosis in hamsters. Increases in elastin may therefore be a common feature of interstitial pulmonary fibrosis and may contribute to the altered lung mechanics seen in this disease.

Amiodarone↗
PubMed1986

Interleukin 1 secretion from human alveolar macrophages in lung disease.

Interleukin 1 secretion from human alveolar macrophages was studied in patients with interstitial pulmonary fibrosis, sarcoidosis, and the acquired immunodeficiency syndrome with pneumonitis and compared to secretion from alveolar macrophages of normal volunteers. Macrophages lavaged from the lungs were stimulated with 10 micrograms/ml of lipopolysaccharide and cultured for 24 hr. In some cases macrophages were also stimulated with 1 microgram/ml lipopolysaccharide. After dialysis of the culture supernatants, interleukin 1 secretion was quantified by the thymocyte proliferation assay and probit analysis and expressed in terms of secretion from 1 million macrophages. Results showed that, on average, macrophages derived from patients secreted more interleukin 1 after stimulation with lipopolysaccharide compared to normal subjects. Mean secretion was significantly greater from macrophages of patients with acquired immunodeficiency syndrome and interstitial pulmonary fibrosis when stimulated with 10 micrograms/ml lipopolysaccharide. Of the 24 individuals studied, spontaneous interleukin 1 secretion was detected from unstimulated macrophages in only 1 patient and 1 normal volunteer. We conclude that alveolar macrophages lavaged from the lungs of patients with inflammatory lung disease have an increased capacity to secrete interleukin 1 on in vitro stimulation with lipopolysaccharide. Possible mechanisms for this increase are discussed.

Acquired Immunodeficiency Syndrome↗
PubMed1986

The fibronectin content of canine lungs is increased in bleomycin-induced fibrosis.

Fibronectin (Fn), a high molecular weight glycoprotein, was found to constitute 0.43% of the normal adult beagle dog lung. The tissue Fn (TFn) was solubilized by sequential chemical extractions and quantified by ELISA (enzyme-linked immunoabsorbent assay). Subsequent plasmin digestion did not appear to solubilize significantly more Fn. Since 70% of the lung tissue was solubilized by the extractions and plasmin digestions, the TFn quantified represented the bulk of lung Fn. The TFn was identical to plasma fibronectin in the ELISA and one can infer that the Fn molecule is not significantly altered as it is incorporated into the lung connective tissue matrix. Lungs from beagles in which fibrosis had been induced with bleomycin contained 0.99% Fn, more than a twofold increase over normal. In the ELISA TFn from fibrotic lungs gave an inhibition curve of the same shape as did TFn from normal lungs. Thus, Fn from fibrotic lungs is not different qualitatively from Fn from normal lungs in any way detectable with this antiserum. The TFn content of plasmin digests of intact lung was less than that of extracts, which was the converse of results obtained on placenta (B. A. Bray (1985) Biochem. J. 226, 811-815). This difference between lung TFn and placental TFn may be due to differences in degree of glycosylation, which determines susceptibility to proteases.

Animals↗
PubMed1986

Secretion of interleukin 1/leucocytic pyrogen from endotoxin-stimulated human alveolar macrophages is unaffected by indomethacin.

Human alveolar macrophages obtained from 7 normal volunteers and 7 patients with lung disease were stimulated with endotoxin (lipolysaccharide) to induce interleukin 1/leucocytic pyrogen (IL1/LP) secretion. Using the thymocyte assay we quantitated IL1/LP activity in macrophage supernatants obtained after 24 h. 10 micrograms/ml lipopolysaccharide stimulated alveolar macrophages to secrete significantly more IL1/LP activity than did 1 micrograms/ml. Apart from one patient with sarcoidosis, the presence of indomethacin did not significantly inhibit the quantity of IL1/LP secreted in response to LPS. We also demonstrated that the presence of indomethacin did not affect the response of thymocytes to IL1/LP. We conclude that the secretion of IL1/LP by human alveolar macrophages in response to endotoxin is not significantly reduced by the cyclooxygenase inhibitor indomethacin.

Animals↗
PubMed1986

Interleukin-1 secretion by human alveolar macrophages stimulated with endotoxin is augmented by recombinant immune (gamma) interferon.

We investigated the role of the macrophage-activating factor gamma interferon (IFN) in the in vitro secretion of interleukin-1 (IL-1) from human alveolar macrophages. Macrophages were obtained from 6 normal volunteers and 5 patients by bronchoalveolar lavage. Macrophages were adhered to a plastic surface and then stimulated to secrete IL-1 with concentrations of endotoxin (LPS) ranging from 1 ng/ml to 10 micrograms/ml. Unstimulated macrophages served as a control. Recombinant gamma IFN was added to LPS-stimulated or unstimulated macrophage cultures in concentrations ranging from 0.25 to 1,000 U/ml. After 24 h of culture, supernatants were removed and IL-1 activity was measured by the thymocyte proliferation assay. Gamma IFN directly induced IL-1 secretion from macrophages of 2 of the subjects. In the presence of LPS, gamma IFN markedly augmented IL-1 secretion from macrophages of 10 of the 11 subjects. Gamma IFN could prime macrophages for increased response to LPS after 1 h of incubation. We conclude that gamma IFN provides a modulating signal for in vitro LPS-induced IL-1 secretion from alveolar macrophages and may enhance macrophage reactivity to inflammatory mediators in vivo.

Animals↗
PubMed1986

Synthesis of crosslinked elastin by a mesothelial cell culture.

Synthesis of crosslinked elastin was measured in cultures of pleural mesothelial cells. Results indicate that mesothelial cells are a rich source of crosslinked elastin and may therefore be useful for in vitro studies of this connective tissue component.

Autoradiography↗
PubMed1985

Stimulation of lung lysyl oxidase activity in hamsters with elastase-induced emphysema.

Lysyl oxidase activity was measured in lung extracts of hamsters with elastase-induced emphysema 8 days after administration of the enzyme and again after 2, 3, and 4 wk. Levels of activity rose rapidly to 7 times the base values determined in the lungs of saline-injected control animals. In parallel with the increase in lysyl oxidase activity, the rate of 14C-lysine incorporation into desmosine and isodesmosine was at its maximum 1 wk after elastase administration, reflecting the lysyl-oxidase-mediated cross-link formation, which is the final step in the resynthesis of the pulmonary elastin destroyed by the elastolytic insult.

Amino Acid Oxidoreductases↗