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M Calvitti

Publications and source records attributed to M Calvitti.

32 records · Page 2Linked to original sources
PubMed1997

Phenotype expression of human bone cells cultured on implant substrates.

Bone cells derived from the human jaw were cultured on titanium, titanium coated with hydroxyapatite (THA) or with plasma spray (TPS) to study the behaviour of the cells anchored to implant substrates. Bone cells were cultured in MEM with the addition of [3H]-thymidine to evaluate cellular proliferation, and [3H]-glucosamine to evaluate GAG synthesis and accumulation in the extra-cellular matrix (ECM). Moreover, to study the degradation of GAG bone cells were cultured in the presence of NH4Cl, an amine known to inhibit lysosomal activity. Our results show that TPS is the substrate that favours both cellular proliferation and the accumulation of GAG in the ECM.

Ammonium Chloride↗
PubMed1997

Phenotype expression of gingival fibroblasts cultured on membranes used in guided tissue regeneration.

Human gingival fibroblasts were cultured in vitro using as substrates an extracellular matrix (matrix) and polytetrafluoride (PTFE) membranes, which are used in guided tissue regeneration. To test the degree of biocompatibility of these membranes, the cellular proliferation and the accumulation of extracellular matrix (ECM) macromolecules were considered as parameters. The fibroblasts were cultured in vitro for 24 and 48 hours without serum on plastic, matrix, and PTFE membranes in the presence of 3H-thymidine, 3H-glucosamine, and 3H-proline to study the neo-synthesis of DNA, glycosaminoglycans (GAG), and collagen proteins, respectively. Studies on cell proliferation showed that fibroblasts grown on matrix membrane significantly increased 3H-thymidine incorporation, while fibroblasts grown on PTFE membrane decreased 3H-thymidine incorporation, compared to plastic used as a control. Moreover, the PTFE membrane induced a marked decrease of collagen and GAG accumulation both in the cellular and extracellular pool, while the matrix membrane provoked a decrease of the two macromolecules in the cellular pool and an increase in the extracellular one, compared to the control. The data we obtained demonstrate that matrix membranes are the most suitable to stimulate both cellular proliferation and ECM macromolecule accumulation.

Adult↗
PubMed1996

Metal substrates influence the release of glycosaminoglycan and transforming growth factor beta by human bone cells.

Bone cells derived from human jaw were isolated from explants and grown in vitro. Subcultures were cultured on plastic (control) and metal substrates for 24 and 48 hours in medium containing 3H-glucosamine and labeled glycosaminoglycan (GAG) accumulation was measured. In bone cells cultured on metal substrates there was an evident reduction in the synthesis and secretion of radiolabeled macromolecules compared to bone cells cultured on plastic. Moreover, the accumulation of single GAG classes was specific for each substrate tested. The results showed that titanium was the only metal substrate studied in which the percentage of individual GAG classes remained the same as control cultures. GAG reduction was due to a decreased synthesis and not to an increased degradation as shown by the decrement of exoglycosidase activity. The metals also reduced the activity of transforming growth factor beta (TGF beta), measured using interleukin-1 assay method, a factor involved in the various phases of bone remodeling; in this case, too, cells grown on titanium showed the highest TGF beta activity compared to the other metal substrates studied. The results indicate that the substrate to which the cells adhere do exhibit specific differences in GAG composition and TGF beta activity. The differences observed may be important during in vivo events such as guided tissue regeneration and bone deposition.

Acetylglucosaminidase↗
PubMed1996

[A case of anaplastic carcinoma of the thyroid. Clinico-pathological and therapeutic aspects and review of the literature].

A case of anaplastic carcinoma of the thyroid observed in a 72-year-old female patient, admitted with previous diagnosis of Riedel's thyroiditis, is reported. Clinicopathologic features and management of this rare neoplasm are discussed and Literature is reviewed. Anaplastic cancer is a locally and systemically aggressive histologic type, occurring more frequently in older patients and in those with a history of benign and/or malignant thyroid disease. Because long-term survival was seen most commonly in well-localized anaplastic tumors, a more aggressive approach to thyroid lesions, especially in the elderly, may be warranted to improve early diagnosis and effectiveness of therapy of this nearly always lethal neoplasm. Although patients can rarely be cured, efforts should be made to control the disease locally by combined treatment including surgery and radiochemotherapy, which is found to be, at times, a national palliative therapeutic approach despite patient's advanced age.

Aged↗
PubMed1995

Internalization of Candida albicans and cytoskeletal organization in macrophages and fibroblasts treated with concanavalin A.

This paper investigates the ability of macrophages and of non-typically phagocitic cells such as fibroblasts to internalize 51Cr-labelled C. albicans in presence or in absence of lectin concanavalin A (Con A). The results obtained demonstrate that fibroblasts are also able to internalize C. albicans and that this property is potentiated by the presence of Con A. Lectin modifies only the phenotype of the fibroblast, which, poorly attached to the substrate, is globular in shape. Despite reduced cellular spreading, phagocytosis is stimulated by the lectin. In both cell populations, changes in the organization of some cytoskeletal proteins such as tubulin, actin and alpha-actinin are evident during the C. albicans infection; such rearrangements are more evident and longlasting in the fibroblasts treated with Con A.

Actinin↗
PubMed1994

Interleukin-1 and interleukin-6 differentially regulate the accumulation of newly synthesized extracellular matrix components and the cytokine release by developing chick embryo skin fibroblasts.

In the present study, we demonstrate that both interleukin-1 (IL-1) and interleukin-6 (IL-6) induced a significant decrease in glycosaminoglycan (GAG) synthesis and, more strikingly, secretion by 7 and 13 day-old chick embryo skin fibroblasts. We demonstrated that interleukin treatment also inhibited the synthesis of collagenase-digestible proteins (type I collagen). In addition, tissue culture supernatants (conditioned media, CM) were tested for reactivity for IL specific ELISAs and for their ability to stimulate proliferative responses in mouse thymocytes and hybridoma cells. Our findings demonstrate that chick embryo skin fibroblasts spontaneously produce IL-1 and, in even greater amounts, IL-6. Highest levels of interleukin secretion were found in the CM of 13 day-old fibroblasts and the IL-1 beta isoform was predominant over IL-1 alpha. Pretreatment of the fibroblasts with either IL-1 or IL-6 increased the secretion of both cytokines. Increased IL-1 levels were correlated with enhanced IL-1 bioactivity in the CM of IL-6 treated fibroblasts. By contrast, the raised concentrations of IL-1 in the CM of IL-1 treated cells and IL-6 in the CM of IL-1 or IL-6 treated fibroblasts failed to translate into augmented bioactivity. These observations, taken together, indicated that IL-1 and IL-6 are able to regulate the synthesis and secretion of ECM macromolecules of developing connective tissues and the cytokine release by chick embryo skin fibroblasts.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Modulation of phenotype and cytoskeleton architecture by interleukin-1 alpha in human osteoblast-like cells in vitro.

Interleukin-1 alpha, a growth factor produced by macrophages as well as many other types of cells, is able to modulate biosynthetic activities in bone cells. In this work, the authors show that the administration of interleukin-1 alpha to osteoblast-like cells in vitro induces a marked change in cell morphology, which becomes dendritic, with a smaller cellular body and numerous prolongations. The morphological changes are also accompanied by an altered expression in the pattern of cytoskeleton proteins.

Cells, Cultured↗
PubMed1991

Analysis of the patterns of expression of mRNAs for the alpha- and beta-subunits of the lysosomal enzyme beta-N-acetylhexosaminidase in mouse epididymis and testis.

mRNA for the alpha- and beta-subunits of mouse beta-N-acetylhexosaminidase were detected in tissue sections of epididymis and testis using 3H-labelled antisense RNA probes by hybridization in situ. There were clear differences in the intensity of the signals given by the two tissues with alpha-subunit mRNA being more abundant in testis than epididymis, while the opposite was so with beta-subunit mRNA. Differences in the isoenzyme patterns of the two tissues are likely to be due, at least in part, to differences in transcription by the Hexa and Hexb genes.

Animals↗
PubMed1990

Fate of human albumin microsphere and spherocyte radioaerosols in the human tracheobronchial tree.

Human albumin microspheres (99mTc-HAM; 7-25 microns) and spherocytes (99mTc-S; 4-4.5 mu) are particles used for lung mucociliary clearance (MCC) measurements. If radiolabelled HAM aerosols are sent through an airway model to a screen, they appear peripherally distributed, whereas S present a more central and homogeneous distribution. The radioscanning evaluation of particle sedimentation in saline-filled tubes shows quite a different behavior pattern for S, HAM, and surfactant-coated HAM (S-C HAM). In these experimental conditions, S-C HAM and HAM floating properties were better than those of S. This could be explained by physical-chemical factors. Looking for the fate of organic particles after inhalation, we performed multiple bronchial biopsies in seven bronchitic patients, 2 h following inhalation of HAM and S. Scanning electron microscopy revealed that most of S was floating on the mucus layer, while HAM appeared deeply imbedded inside the mucus and partially digested. The same study performed on three bronchitic patients after S-C HAM inhalation, shows that S-C HAM float like S. In vitro, the time-course of tryptic digestion is similar for HAM and for S. However, in vivo, the different location of each particle on the bronchial surface might lead to a different digestion by trypsin and by PZ-peptidase, which are dosable in pathologic mucus. In our opinion, if HAM are coated with surfactant, this should improve the mucus-HAM interaction, thus helping to control variability in lung radioaerosol MCC studies.

Aerosols↗
PubMed1990

Cytoskeletal and DNA synthesis modification by concanavalin A in embryonic fibroblasts maintained in serum-free and serum-added medium.

The administration of lectin concanavalin A (Con A) to in vitro cultures of chick embryo fibroblasts caused dose-dependent changes in cell shape, cytoskeleton network and DNA synthesis. After 6 hrs. even a low doses of Con A produced evident effects in serum-free cultures, whereas higher doses were required to cause alterations in cells cultured in serum-added medium. As the sugar competitor mannoside abolishes the effects, it would seem that the lectin acts by binding to transmembrane receptors and that the fibronectin present in the serum engages the receptors so that they are not available to Con A.

Animals↗
PubMed1990

Restoration of a normal phenotype, microtubular pattern and DNA synthesis in embryonic fibroblasts concanavalin A pretreated.

The present research investigated the time required for reconstructing normal microtubular pattern and the phenotype of cells after short-term (30 min.) and long-term (24 hrs.) pretreatment with the lectin concanavalin A (Con A). Short-term pretreatment led to the formation of incomplete tubules within 2 and 24 hrs. in cells cultured in 199 medium alone. The addition of serum to the medium reversed the globular phenotype and allowed the formation of normal microtubules, even after prolonged pretreatment with Con A. Whereas long-term Con A treatment provoked a reduction in DNA synthesis in 199 alone, in serum-added 199 the percentage of 3H-thymidine incorporation of treated cells tended to reach that of controls over time.

Animals↗
PubMed1989

Sarcoidosis: an alveolar macrophage disease?

The Authors focus on new functions of alveolar macrophages (AM) from patients with active pulmonary sarcoidosis. They show that sarcoid AM present a candidacidal activity higher than normal controls, probably due to an enhanced phagocytic efficiency. Furthermore, after LPS stimulation cultured sarcoid AM secrete larger amount of interleukin 1 (IL-1) and of tumor necrosis factor (TNF) than normal controls. In conclusion, a new key role is emerging for sarcoid AM: not only an antigen-presenting cell, but a cell with a great primitive potential in modulating the inflammatory process.

Bronchoalveolar Lavage Fluid↗
PubMedDate not supplied

[Mesothelial cyst of the diaphragm. Report of a case and review of the literature].

A case of mesothelial cyst of the right hemidiaphragm in a 44 year old man is reported. Origin (most likely due to a recess of the primary coelomiatic cavity), topographical, histological and therapeutic features are discussed, stressing that it is now more frequently recognised thanks to progress in diagnostic imaging techniques. Complete surgical excision is mandatory to definitely differentiate such lesion from primary diaphragmatic neoplasm, not infrequently malignant.

Adult↗