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P Calzoni

Publications and source records attributed to P Calzoni.

14 recordsLinked to original sources
PubMed1997

Iron mobilization from crocidolite as enhancer of collagen content in rat lung fibroblasts.

Asbestos exposure causes pulmonary fibrosis by mechanisms that remain uncertain. There is increasing evidence that iron from asbestos is responsible for many of its effects. In this paper, we investigated the effect of iron mobilized from crocidolite asbestos on collagen content in rat lung fibroblast cultures under serum-free conditions. Crocidolite (2, 4, 6 microg/cm2 well) increased collagen content in a dose-dependent manner (+42 +/- 8, +92 +/- 10, and +129 +/- 13% vs controls). This effect was specific for collagen, since it did not alter total protein content and was inhibited by the iron chelator deferoxamine (DFO). Preincubation of crocidolite with citrate (1 mM) for 48 hr resulted in iron mobilization (51 microM) and increased collagen production (>3-fold) in treated cells. These effects occurred without the intervention of serum factors. The absence of cell damage, proliferation or lipid peroxidation leads to the supposition that iron from crocidolite per se may act as a profibrogenic agent. Although the in vivo participation of other cells and factors cannot be excluded, we conclude that iron released from crocidolite plays a role in collagen increase occurring during asbestosis.

Animals↗
PubMed1994

Neutrophil lysosomal dysfunctions in mutant C57 Bl/6J mice: interstrain variations in content of lysosomal elastase, cathepsin G and their inhibitors.

In this paper we report the serum antiprotease screening and the biochemical and functional characteristics of neutrophils in a variety of mouse strains with different susceptibilities for developing a protease-mediated injury. C57Bl/6J mice and their mutants tight-skin and pallid have a lower serum elastase inhibitory capacity (-30, -65 and -70% respectively) than other inbred strains (i.e. NMRI and Balb/c, which both have similar values). We demonstrate that these values are a consequence of a decreased concentration of the alpha 1-protease inhibitor for elastase [PI(E)], which is the major serum inhibitor of elastase and cathepsin G. In addition, neutrophil lysosomal dysfunctions characterized by abnormally high contents of elastase and cathepsin G, or defective lysosomal secretion are observed in tight-skin and pallid mice respectively. Another C57Bl/6J mutant with lysosomal abnormalities is the beige mouse. Negligible amounts of elastase and cathepsin G, as well as defective neutrophil degranulation, have been described previously in this strain. We found, however, discrete amounts of a latent form of neutrophil elastase that undergoes a spontaneous activation by a protease-dependent mechanism. We also report that neutrophil cathepsin G in this mouse is tightly bound to lysosomal membranes, but is released in near normal quantities during exocytosis. Cytosolic elastase and cathepsin G inhibitors, which were previously reported as being specific for the beige neutrophils, have also been detected in all the examined strains. Neutrophil functions, lysosomal enzyme content and serum antiprotease screening may represent key elements in the protease-antiprotease balance and may explain the different interstrain susceptibility to developing lesions in which an elastolytic activity has been implicated.

Amino Acid Sequence↗
PubMed1994

Cardiac collagen changes during the development of right ventricular hypertrophy in tight-skin mice with emphysema.

The tight-skin (Tsk) mouse is a genetic model of pulmonary emphysema. In this mouse, right ventricular hypertrophy (RVH) starts to develop at approximately 8 months of age, probably as a consequence of the emphysema. The aim of the present study was to investigate cardiac collagen synthesis, content, and types both before and during the development of RVH. Collagen synthesis, assessed by the [3H]proline incorporation method, was significantly increased in the right ventricle of 3-month-old Tsk mice. This was accompanied by a marked increase in right ventricle collagen content. Collagen typing showed no difference from controls. At 8 months of age collagen synthesis had returned to control values, right ventricular collagen content was elevated but held lower values than at 3 months, and collagen typing showed a prevalence of the more compliant type III. By 16 months of age, right ventricular collagen content had returned to control values and there was a shift in collagen types due to a relative increase of the more rigid type I. At 24 months of age right ventricular collagen content was increased again and collagen type I continued to predominate. These results suggest a dynamic role for collagen both before and during the development of RVH secondary to emphysema.

Animals↗
PubMed1994

Collagen breakdown products and lung collagen metabolism: an in vitro study on fibroblast cultures.

BACKGROUND: In fibrotic diseases such as pulmonary fibrosis there is evidence suggesting enhanced synthesis and degradation of lung connective tissue components, including collagen. It has therefore been hypothesised that products of collagen degradation may have a role in the promotion of collagen deposition. In support of this hypothesis, it has recently been shown that intravenous injection of lung collagen degradation products in experimental animals stimulated collagen synthesis leading to increased collagen deposition and diffuse interstitial lung disease. METHODS: Rabbit and human fibroblast cultures from lung and skin were used as an in vitro model to study the responses of these cells to rabbit collagen degradation products. The effects of an acute exposure to collagen degradation products on synthesis of collagen and noncollagenous protein have been studied in confluent cultures by [3H]-proline incorporation. The effects of collagen degradation products on fibroblast proliferation and production of genetic types of collagen have also been investigated. RESULTS: The acute exposure of rabbit lung fibroblast cultures to collagen degradation products significantly increased collagen synthesis without affecting non-collagenous protein synthesis. This effect was dose related, specific for lung fibroblasts, and species specific. Collagen degradation products altered the rate of synthesis of genetic types of collagen with a consequent decrease of type III/I+III collagen ratio (0.26 (0.04) treated with collagen degradation products; 0.45 (0.02) controls). These effects occurred without the intervention of serum factors. In addition, collagen degradation products neither affected fibroblast proliferation nor selected specific clones emphasising one type of collagen. CONCLUSIONS: These results suggest that collagen degradation products can influence lung collagen metabolism by stimulating collagen synthesis. The regulation of collagen mass by collagen degradation products may be of importance in lung collagen homeostasis in vivo.

Animals↗
PubMed1993

The pallid mouse. A model of genetic alpha 1-antitrypsin deficiency.

BACKGROUND: The current hypothesis of pulmonary emphysema is based on an alteration of the protease-antiprotease balance within the lower respiratory tract. This hypothesis derives largely from studies in emphysema patients with genetic deficiency in serum alpha 1-antitrypsin. In animals, naturally occurring deficiency in serum elastase inhibitory capacity associated with early development of emphysema has been reported in the tight-skin mouse. We describe here a mouse model of genetic deficiency of alpha 1-antitrypsin in which emphysema occurs late in life. EXPERIMENTAL DESIGN: A genetic deficiency in serum alpha 1-antitrypsin was investigated in pallid mice, a strain with spontaneous occurring emphysema. Additionally, the possible pathogenetic role of an elastase-anti-elastase imbalance in pallid mice was investigated using molecular biologic, biochemical, histologic, ultrastructural, and immunoelectron microscopic methods. RESULTS: Pallid mice have markedly low levels of serum alpha 1-antitrypsin associated with a severe deficiency in serum elastase inhibitory capacity. However, they have normal alpha 1-antitrypsin mRNA levels in the liver. At ultrastructural examination, disruption of alveolar septa is first seen at 8 months of age. At histologic examination, some patchy areas of air-space enlargement with destruction of alveolar septa are seen from 12 months of age onward. These histologic changes are paralleled by a decrease in lung elastin content. The development of the pulmonary lesions is preceded by an alveolar elastolytic burden detected by an immunogold technique. CONCLUSIONS: All these data suggest that the lung changes in pallid mice are the result of an elastolytic process due to a severe inborn deficiency of serum alpha 1-antitrypsin. This animal model reproduces important features of the human condition and may provide new insights into the pathogenesis of emphysema.

Animals↗
PubMed1992

Identification of elastase in human eosinophils: immunolocalization, isolation, and partial characterization.

Although an elastolytic activity in eosinophil-rich cell fractions from mice has been reported, this enzyme has not been purified and characterized as yet in any mammalian species. Eosinophilic elastase was isolated from human eosinophil fragments (cytosomes) obtained from normal and eosinophilic subjects. The enzyme was purified to apparent electrophoretic homogeneity by fast protein liquid chromatography. The enzyme shows the same physical properties of the major elastase isoenzyme of human neutrophils. In addition, like monocyte elastase, it reacts with a monoclonal antibody against human neutrophil elastase. The biochemical similarities observed between the above-mentioned enzymes and the immunolocalization findings strongly support the idea that human eosinophils and neutrophils contain the same enzyme activity. Eosinophils show immunoreactive material in both types of dense cytoplasmic granules. This observation supports the current hypothesis that the different types of eosinophilic granules represent successive morphological stages of maturation.

Cross Reactions↗
PubMed1992

Lung collagen synthesis and deposition in tight-skin mice with genetic emphysema.

The tight-skin (Tsk) mouse is a genetic model of pulmonary emphysema linked to a deficiency of serum antielastase. In this mouse occurrence of connective tissue abnormalities in various organs (systemic scleroderma) has been reported. The aim of the present work was to study lung collagen synthesis and deposition in Tsk mice. No differences in the collagen synthesis rate and morphology at the ultrastructural level were found in Tsk mice at birth. At 2 months of age, a marked increase in collagen was observed within the alveolar septa. At this time, an increased lung collagen synthesis, assessed by determining prolyl hydroxylase activity and incorporation of radiolabeled proline, was found in Tsk mice with respect to control mice. However, due to the ongoing parenchymal destruction, the values of total lung collagen at 6 and 12 months of age were only moderately but significantly increased with respect to those observed at 2 months. As a consequence, a progressive accumulation of lung collagen fibers was observed in the residual septa. The increase in collagen deposition was accompanied by a relative increase in type I collagen. Although the data in the literature would suggest a genetic cause for the lung collagen change in Tsk mice, the data presented here indicate that the change in lung collagen metabolism may be a part of a remodeling process taking place after lung destruction.

Animals↗
PubMed1991

An elastolytic proteinase from rabbit leukocytes: purification and partial characterization.

A proteinase with elastolytic activity was isolated from granules of rabbit bloodstream leukocytes, and purified to apparent homogeneity by a multi-step procedure consisting of ammonium sulfate precipitation, batch fractionation on DEAE-Sephadex A-50, and finally by preparative isoelectric focusing (IEF) on Sephadex G-75 Superfine. The molecule weight of the enzyme, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), was 28,500. This enzyme shows an isoelectric point at pH 9.0. The proteinase is active against natural elastins as well as toward Suc-(Ala)3-NA, Methoxy-Suc-(Ala)2-Pro-Val-NA, and (to a lesser extent) against Suc-(Ala)2-Pro-Leu-NA and Boc-Ala-ONp. The inhibition profile of the isolated enzyme indicates that rabbit granulocyte elastase belongs to the group of serine proteinases. Inhibition by some natural proteinase inhibitors is also observed. Unlike other mammalian elastases, it is insensitive to elastatinal.

Amino Acid Sequence↗
PubMed1990

In vivo stimulation of lung collagen synthesis by collagen derived peptides.

In the present work we examined the "in vivo" effects of collagen breakdown products derived from elastase digestion on lung collagen synthesis in rabbits. It was found that i.v. injection of collagen peptides greatly enhances the collagen synthesis rate while does not affect the synthesis of non collagenous proteins. The increase of incorporation of 3H-proline in lung collagen parallels that of prolyl hydroxylase activity. The collagen synthesis, expressed as fractional rate (% day), amounted to 15% day in treated animals, resulting in a significant increase with respect to controls (11.7% day). The observations reported provide evidence that collagen breakdown products stimulate lung collagen synthesis and may play a role in collagen homeostasis.

Animals↗
PubMed1990

Development of interstitial lung fibrosis by long-term treatment with collagen breakdown products in rabbits.

We recently demonstrated that collagen breakdown products derived from elastase digestion (CDP) can stimulate "in vivo" lung collagen synthesis. The present work deals with the morphological and biochemical characteristics of an experimental model of lung fibrosis developed in rabbit by long-term treatment with CDP. Stimulation of collagen synthesis by CDP resulted in a significant thickening of alveolar septa due to accumulation of fibroblasts and a marked deposition of collagen fibrils as revealed by light as well as electron microscopy. Biochemical analysis confirmed the increase in lung collagen deposition. Total collagen content as determined by hydroxy-proline analysis was increased in CDP-treated animals of about 56% in respect to control animals. A relative increase of type I collagen in respect to type III was also observed. An additional interesting observation was a progressive hyperplasia of type II pneumocytes. Unlike other experimental models of lung fibrosis, the collagen deposition in our condition is not preceded or associated with inflammatory or degenerative processes. This fact renders this model very suitable to study matrix-cell interactions in pulmonary fibrogenesis.

Analysis of Variance↗
PubMedDate not supplied

[Cohort study of mortality among leather tanners in the Lower Valdarno area].

BACKGROUND: Epidemiological studies of tanners have shown increased risk for a number of cancer sites, namely: lung, bladder, kidney and urinary organs as well as stomach, intestine, pancreas, nose and nasal cavities, together with leukemias and soft tissue sarcomas. OBJECTIVE: To study cause specific mortality of leather tanners in Tuscany (Valdarno Inferiore area). METHODS: The cohort included 4874 workers (4150 males and 724 females) employed in 92 tanneries operating in 1996 (Valdarno Inferiore Tanneries Census) which were also operating on 31-12-1970. Ascertainment of vital status was completed for all individuals on 31-12-1998 (end of follow-up), and the cause of death was known for all deceased subjects. Demographic and work history data were obtained from factory payrolls. Regional mortality rates were used for comparison to calculate SMR (Standardised Mortality Ratio) and 90% Confidence Intervals (CI). In addition to the overall cohort analysis, for men only separate analyses were completed for finishers, chrome tanners and vegetable tanners. RESULTS: The study showed an increased mortality from lung cancer among finishers, Standardised Mortality Ratio (SMR) 145, 19 observed (obs) (90% Confidence Intervals, 90% CI 95-212), from bladder cancer in the overall cohort (SMR 134, 9 obs, 90% CI 70-233) and among finishers (SMR 125, 2 obs, 90% CI 22-393) and from pancreatic cancer among finishers (SMR 120, 2 obs, 90% CI 21-379). Mortality from lymphoemopoietic cancer is above expected, and the increase is mainly due to myeloid leukaemia, both in males (SMR 208, 5 obs, 90% CI 82-437) and females (SMR 599, 2 obs, 90% CI 106-1887). No deaths from soft tissue sarcoma were observed. A new finding of the study was the increased mortality from cancer of the endocrine glands (SMR 566, 4 obs, 90% CI 194-1297), psychiatric disorders (SMR 195, 6 obs, 90% CI 85-385) and blood diseases (SMR 329, 4 obs, IC 90% 112-752). CONCLUSIONS: The observations of increased lung cancer mortality among finishers, of bladder cancer in the overall cohort and among finishers, as well as an increase in pancreatic cancer among the latter, confirm previous epidemiological findings among tanners. The increase in myeloid leukemia mortality for both males and females, and the absence of deaths from cancer of the connective tissue, which includes soft tissue sarcomas, are worthy of note. The results should be valued with caution, given the small number of cases and the novelty of some observations.

Adult↗