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Biomedical subjects

G Stabellini

Publications and source records attributed to G Stabellini.

At least 19 recordsLinked to original sources
PubMed2006

Proteoglycan synthesis in bovine articular cartilage explants exposed to different low-frequency low-energy pulsed electromagnetic fields.

OBJECTIVE: To investigate the role of pulsed electromagnetic field (PEMF) exposure parameters (exposure length, magnetic field peak amplitude, pulse frequency) in the regulation of proteoglycan (PG) synthesis of bovine articular cartilage explants. METHODS: Bovine articular cartilage explants were exposed to a PEMF (75 Hz; 2 mT) for different time periods: 1, 4, 9, 24 h. Then, cartilage explants were exposed for 24 h to PEMFs of different magnetic field peak amplitudes (0.5, 1, 1.5, 2 mT) and different frequencies (2, 37, 75, 110 Hz). PG synthesis of control and exposed explants was determined by Na2-35SO4 incorporation. RESULTS: PEMF exposure significantly increased PG synthesis ranging from 12% at 4 h to 17% at 24 h of exposure. At all the magnetic field peak amplitude values, a significant PG synthesis increase was measured in PEMF-exposed explants compared to controls, with maximal effect at 1.5 mT. No effect of pulse frequency was observed on PG synthesis stimulation. CONCLUSIONS: The results of this study show the range of exposure length, PEMF amplitude, pulse frequency which can stimulate cartilage PG synthesis, and suggest optimal exposure parameters which may be useful for cartilage repair in in vivo experiments and clinical application.

Animals↗
PubMed2005

In vitro human osteoblast and extracellular matrix changes after transforming growth factor beta 1 treatment.

AIMS: Normal bone tissue is characterised by a balancing of osteoblast and osteoclast activity. The activity and differentiation of these cells are regulated by vitamins, hormones and cytokines. The action of these factors on bone tissue cells depends on the composition and mineralisation of extracellular bone matrix. In particular, transforming growth factor beta 1 (TGFbeta1) acts on collagen fibres, glycosaminoglycan secretion and on the enzymes correlated to the turnover of glycosaminoglycans. The normal functions of bone tissue also depend on its mineralisation, which is highly altered in the process of uraemia. METHODS: In this study, we analysed in vitro the effect of transforming growth factor beta on osteoblast proliferation, collagen synthesis and glycosaminoglycan secretion with 3H-thymidine, 3H-proline or 3H-glucosamine incorporation, and on enzymes, such as beta-N-acetyl-D-glucosaminidase and beta-glucuronidase, involved in extracellular matrix turnover. Moreover, phosphatase alkaline activity and osteocalcin related to mineralisation of extracellular matrix were determined. RESULTS: Our data show that TGFbeta1 significantly decreases 3H-thymidine and 3H-proline incorporation and increases (p < or = 0.01) extracellular sulphated glycosaminoglycan synthesis. It also increases osteocalcin levels, phosphatase alkaline, beta-N-acetyl-D-glucosaminidase and beta-glucoronidase activities. CONCLUSION: TGFbeta1 changes the synthesis of extracellular matrix components by osteoblasts. These variations favour the action of cytokine and osteoclasts. Since the TGFbeta1 accumulates in bone tissue and increases during uraemia, with due limitations this action leads to an imbalance between synthesis and degradation and could explain bone alterations in uraemic patients.

Acetylglucosaminidase↗
PubMed2004

Megaesophagus in an asthmatic patient and beta2 stimulant treatment by inhalation.

Megaesophagus is a severe esophageal malformation. We report a case of megaesophagus in an asthmatic patient affected by congenital non-haemolytic anaemia and undergoing beta2 stimulant treatment by inhalation. Our case could be due to chronic beta2 receptor stimulation with imbalance of alpha and beta receptor, without any implication of favism.

Adult↗
PubMed2004

Extracellular glycosaminoglycan changes in healthy and overgrown gingiva fibroblasts after cyclosporin A and cytokine treatments.

BACKGROUND: It has been demonstrated that cyclosporin A (CyA) blocks the immune system, acts on cytoskeleton and stimulates the production of extracellular matrix (ECM) and transforming growth factor-beta1 (TGF-beta1). This cytokine, such as transforming growth factor-alpha (TGF-alpha), induces deposition of glycosaminoglycans (GAG), proteoglycans and collagen fibres in the ECM. METHODS: In this work, we examined the effect induced by CyA, TGF-beta1 and TGF-alpha on cultures of healthy and overgrown human gingival fibroblasts in order to evaluate the glycosaminoglycan, cytoskeletal changes and the behaviour of fibroblasts after concanavalin A (Con A) treatment. Moreover, we examined gingival biopsies by Alcian blue histochemical staining and electron transmission microscopy. RESULTS: Total and extracellular sulphated GAG in overgrown gingiva specimens and in derived fibroblast cultures treated with CyA and cytokines were significantly higher than controls. The action of cytokines was increased (P < or = 0.01) compared with CyA with a greater effect of TGF-alpha in comparison with TGF-beta1; the electron microscopy showed ECM accumulation. The agglutinations showed the heterogeneity of fibroblast populations. CONCLUSIONS: Stimulation with Con A showed that the fibroblast population had cell surface heterogeneity, and could respond in a different way to both CyA and cytokine stimulus. Moreover, increased synthesis of GAG in overgrown gingiva compared with synthesis in normal fibroblasts before CyA treatment suggests a possible genetic origin of damage. As not all CyA-treated patients develop gingival overgrowth, a genetic predisposition may explain the different responses of gingival fibroblast populations.

Adult↗
PubMed2004

Bronchial branching correlates with specific glycosidase activity, extracellular glycosaminoglycan accumulation, TGF beta(2), and IL-1 localization during chick embryo lung development.

During organ differentiation, cell-extracellular matrix (ECM) interactions are required. The components of the ECM, such as glycosaminoglycans, fibronectin, laminin, and collagens, change in relation to cytokine and enzyme activity. Moreover, glycosaminoglycans (GAGs) are components of the ECM that play an important role in both cytokine regulation and cell activities. In this work we studied the accumulation of hyaluronic acid and chondroitin sulfate and heparan sulfate proteoglycans (PGs), beta-N-acetyl-D-glucosaminidase activity, the presence of transforming growth factor beta(2) (TGF beta(2)), and interleukin-1 (IL-1), and the localization of fibronectin, laminin, and collagen I and IV during the early stages of chick embryo lung development. We also determined the levels of hyaluronic acid, chondroitin sulfate, dermatan sulfate, and heparan sulfate GAGs and the activity of beta-N-acetyl-D-glucosaminidase with biochemical methods. Our data show that beta-N-acetyl-D-glucosaminidase activity increases in each cell, especially in the epithelial growth front at the emergence of each bronchial bud, where hyaluronic acid and IL-1 are located in the surrounding mesenchymal areas. Chondroitin sulfate and heparan sulfate PGs, fibronectin, laminin, and collagen I and IV are evident in the area near the basal membrane along the sides where the forming structures are stabilized. Biochemical data show that beta-N-acetyl-D-glucosaminidase activity increases in cells during lung development and is related to GAG decrease and to modifications of the nonsulfated/sulfated GAG ratio. These modifications could change cytokine activity and play an important role in bronchial branching development.

Animals↗
PubMed2003

Chick embryo back skin organ and fibroblast cultures. Extracellular matrix changes induced by dialysate fluid and uraemic toxins in relation to proliferation and differentiation processes.

AIM: During uraemia, an increase of middle molecules and acetylpolyamines occurs. In vitro the middle molecules produce cell toxicity, while the acetylpolyamines stimulate cell proliferation and differentiation. These phenomena are related to protein and extracellular glycosaminoglycan production. The aim of the present study was to evaluate the activity of dialysate, dialysate fluid and the chromatographic peaks of dialysate fractionated by G-15 Sephadex column on chick embryo skin development. METHODS: We evaluated the effects of protein and glycosaminoglycan synthesis using monolayer and organotypic cultures. RESULTS: Our data show that dialysate, chromatographic peak II, and 2 x 10(-8)M N1-acetylspermine cause inhibition of chick embryo skin culture development. On the contrary, 10(-8)M N-acetylornithine and dialysate fluid increase protein and extracellular glycosaminoglycan synthesis, whereas chromatographic peak I does not reveal differences when compared to controls. CONCLUSIONS: These extracelluar changes are related to cell proliferation and feather formation in chick embryo organotypic culture. Moreover, the pH changes of culture medium do not influence the biological action of acetylpolyamines and dialysate fluid on protein and extracellular glycosaminoglycan synthesis. Cell death in the presence of N1-acetylspermine, dialysate and peak II appears unrelated to the apoptotic process. The data show that acetylpolyamines, dialysis fluid, dialysate and chromatographic peaks act on fibroblasts, and are able to modify glycosaminoglycan synthesis. The organotypic cultures of chick embryo back skin could represent a model for studying the modifications of the extracellular matrix induced by these substances.

Animals↗
PubMed2003

Polyamine levels and ornithine decarboxylase activity in blood and erythrocytes in human diseases.

Serum and erythrocyte levels of the polyamines spermine, spermidine and putrescine, as well as ornithine decarboxylase in erythrocytes, were studied in patients with different neoplasms (breast, lung and colon cancer) and in those with a nonmalignant proliferative disease (familial polyposis). The blood levels of polyamines and the spermine/putrescine ratio were significantly higher in all tumors and in nonmalignant colon polyposis. In erythrocyte ornithine decarboxylase activity, spermine and spermidine levels, as well as spermidine/putrescine and spermine/putrescine ratios showed a significant decrease after surgery and chemotherapy. Our data suggest that high levels of blood polyamines and erythrocyte ornithine decarboxylase activity are related to cell proliferation and cancer treatment, but that levels of polyamines in serum and erythrocytes are still significantly high after cancer treatment and are similar to those in polyposis disease. Polyamines are related to nuclear activity during differentiation; therefore, the altered turnover of polyamines could be a sign of abnormal nuclear function. Since polyamines stimulate protooncogene expression, their high levels could be considered an important cofactor in malignant cell transformation.

Adenocarcinoma↗
PubMed2002

Biomembranes enriched with TGFbeta1 favor bone matrix protein expression by human osteoblasts in vitro.

The use of growth factors in oral tissue regeneration is currently under investigation. When growth factors are combined with commercial materials, the in vitro mechanisms of action still remain unclear. The present study first evaluated the capacity of barrier membranes, used in oral surgery, to sequester TGFbeta(1). Resorbable HYAFF, paroguide, poly DL-lactide and nonresorbable PTFE membranes were immersed in MEM containing 0.2 ng (125)I-TGFbeta(1) for different periods of time. It was found that HYAFF membrane and paroguide sequestered the most TGFbeta(1), which was then released in its active form (as shown by the CCL64 cell line bioassay). Untreated membranes and membranes enriched with TGFbeta(1) were then used as substrate for human bone cells to evaluate the synthesis of the osteoblast phenotype, as indicated by specific parameters. Results showed that membranes enriched with TGFbeta(1) increased alkaline phosphatase activity, collagen, and osteocalcin production more than untreated membranes. HYAFF and paroguide membranes, which sequestered the most of TGFbeta(1), were the most suitable for stimulating bone matrix proteins.

Absorbable Implants↗
PubMed2002

Glycosidases during chick embryo lung development and their colocalization with proteoglycans and growth factors.

During development, the epithelial component of the lung goes through a complex orderly process of branching, following strict patterns of space and time. Proteoglycans, glycosaminoglycans and growth factors are fundamental components of the extracellular matrix and perform a key role in differentiative processes. The embryonic chick lung shows a specific glycosaminoglycan composition at different levels of branching and at different embryonic stages. Proteoglycan and glycosaminoglycan accumulation is the result of secretion, absorption and degradation processes. In this pathway, enzymes, such as glycosidases, growth factors and cytokines are involved. We examined the behaviour of glycosidases, such as beta-hexosaminidases (beta-N-acetyl-D-glucosaminidase, beta-N-acetyl-D-galactosaminidase), beta-glucuronidase and beta-galactosidase, during the development of the lung bud. Our data show that the activity of the enzymes is closely linked to the processes of epithelial proliferation, bronchial tubule lengthening and infiltration of the surrounding mesenchyme. The glycosaminoglycans colocalize with transforming growth factor beta2 and interleukin-1 in the basement membrane and in the mesenchymal areas where the epithelium grows, and are complementary to the presence of the glycosidases. In conclusion, the activity of these glycosidases is spatially and temporally programmed and favors the release of the factors and the events which they influence.

Animals↗
PubMed2001

C677T variant form at the MTHFR gene and CL/P: a risk factor for mothers?

Maternal folic acid supplementation in early pregnancy has been suggested to play a role in the prevention of nonsyndromic orofacial cleft, i.e., cleft lip with or without cleft palate (CL/P). Moreover, some authors demonstrated association of the C-->T mutation (C677T), converting an alanine to a valine residue in 5,10-methylenetetrahydrofolate reductase (MTHFR) gene, with other congenital anomalies such as neural tube defects (NTDs). Because of MTHFR's involvement in the metabolism of folate, we investigated 64 CL/P patients and their parents for C677T MTHFR mutation. No linkage disequilibrium was found using the transmission disequilibrium test (TDT). However, a significantly higher mutation frequency was detected in mothers of CL/P patients compared to controls. The odds ratios calculated for mothers having CT or TT genotype, compared to the normal CC genotype, were 2.75 (95% confidence interval 1.30-5.57) and 2.51 (1.00-6.14), respectively. These results support the involvement of the folate pathway in the etiology of CL/P, and indicate an effect of the maternal genotype, rather than influence of the embryo's genotype.

Alleles↗
PubMed2001

Erythropoietin and cardiocirculatory condition in aged patients with chronic renal failure.

BACKGROUND/AIM: The clearest benefit of recombinant human erythropoietin (rHuEPO) in end-stage renal disease is a substantial reduction in transfusion dependency and an improved quality of life. In this report, we describe the efficacy of weekly subcutaneous administration of rHuEPO in 11 elderly patients with anemia secondary to chronic renal failure. METHODS: The role of rHuEPO therapy in increasing the patient's quality of life and in decreasing the hospitalization rates secondary to cardiac morbidity was verified in 11 elderly patients (age range between 66 and 85 years) with anemia due to chronic renal failure. The mean hemoglobin level at the beginning of the study was 8.2 +/- (SD) 0.7 g/dl, and the serum creatinine concentration was 4.8 +/- 1.36 mg/dl. The patients underwent baseline and annual echocardiography, in addition to an electrocardiogram. RESULTS: Most patients experienced a partial regression of left ventricular hypertrophy, and no congestive heart failure was documented. The mean hemoglobin level during rHuEPO therapy increased to 11.3 +/- 1.2 g/dl, while the mean serum creatinine concentration did not change significantly. CONCLUSIONS: Our results confirm that early anemia correction in aged chronic renal failure patients permits improvement of the quality of life, of exercise performance, and of cognitive functions. Reduced transfusion need and regression of left ventricular hypertrophy favor a minor incidence of cardiac morbidity and contribute to reduce health costs.

Aged↗
PubMed2001

Effects of pulsed electromagnetic fields on human articular chondrocyte proliferation.

Low-energy, low-frequency pulsed electromagnetic fields (PEMFs) can induce cell proliferation in several cell culture models. In this work we analysed the proliferative response of human articular chondrocytes, cultured in medium containing 10% FBS, following prolonged exposure to PEMFs (75 Hz, 2.3 mT), currently used in the treatment of some orthopaedic pathologies. In particular, we investigated the dependence of the proliferative effects on the cell density, the availability of growth factors and the exposure lengths. We observed that PEMFs can induce cell proliferation of low density chondrocyte cultures for a long time (6 days), when fresh serum is added again in the culture medium. In the same conditions, in high density cultures, the PEMF-induced increase in cell proliferation was observed only in the first three days of exposure. The data presented in this study show that the availability of growth factors and the environmental constrictions strongly condition the cellular proliferative response to PEMFs.

Aged↗
PubMed2001

Epithelial-mesenchymal interactions and lung branching morphogenesis. Role of polyamines and transforming growth factor beta1.

Lung branching morphogenesis is a result of epithelial-mesenchymal interactions, which are in turn dependent on extracellular matrix composition and cytokine regulation. Polyamines have recently been demonstrated as able to modify chick embryo skin differentiation. In this work we have examined the effects of putrescine and spermidine during chick embryo lung morphogenesis in organotypic cultures by morphological, histochemical and biochemical examination. To verify the role of polyamines, we used specific inhibitors, such as bis-cyclohexylammonium sulphate and alfa-difluoromethylornithine, and transforming growth factor beta1, an ornithine decarboxylase and polyamine stimulator. Our data show that lung morphogenesis is significantly altered following the induced mesenchymal glycosaminoglycan changes. The increase of mesenchymal glycosaminoglycans is correlated with a stimulation of lung development in the presence of polyamines, and with its inhibition when transforming growth factor beta1 is added to the culture medium. The morphometric data show a uniform increase of both the mesenchyme and epithelial branching with spermidine and putrescine stimulus, whereas the mesenchymal substance alone is significantly increased in apical-median lung sections with transforming growth factor beta1 and transforming growth factor beta1 + spermidine lung cultures. Transforming growth factor beta1 and transforming growth factor beta1 + spermidine confirm the blocking of epithelial branching formations and fibroblast activation, and show that polyamines are unable to prevent the blocking of epithelial cells due to the inhibitory effect of transforming growth factor beta1.

Animals↗
PubMed2000

Interleukin secretion, proteoglycan and procollagen alpha(1)(I) gene expression in Crouzon fibroblasts treated with basic fibroblast growth factor.

The present study provides the first evidence that fibroblasts obtained from patients affected by Crouzon syndrome, a rare craniosynostosis, despite mutations in the high-affinity bFGF receptor retain their capacity to respond to bFGF. The growth factor reduces IL-1 secretion, downregulates biglycan and procollagen alpha(1)(I), and increases betaglycan expression. Since betaglycan is a co-receptor for bFGF signalling, an alternative signal transduction pathway is suggested in Crouzon fibroblasts, to explain the documented changes in ECM macromolecule production.

Adolescent↗
PubMed2000

Experimental model for studying the effects of 2-ethylhexyl-phthalate and dialysate on connective tissue.

In order to have a model for studying the possible implications of 2-ethylhexyl-phthalate and dialysate on connective tissue, we evaluated their direct effects on the air pouch lining tissue and on fibroblast cultures. Air pouches were formed on the backs of 60 ten-week-old Wistar rats by subcutaneous injections of 10 ml sterile air. On the tenth day 2 ml sterile air, or 2 ml 5 microg/L or 2 ml 10 microg/L 2-ethylhexyl-phthalate in olive oil, or 2 ml olive oil alone, or 2 ml 5 mg/ml or 12 mg/ml lyophilized dialysate were injected into the air pouches. After sampling at seven or twenty-one days, the rats were killed. The biochemical data showed an increase in sulphated glycosaminoglycans with 2-ethylhexyl-phthalate and dialysate. Electron microscopy findings revealed cellular alterations such as vacuolation and cell remnants with 2-ethylhexyl-phthalate, while the cells of the air pouches treated with dialysate showed regular organelles with increased and dilated cisternae of rough endoplasmic reticulum. Moreover, an increase in collagen fibres surrounding the damaged zones was noticed in 2-ethylhexyl-phthalate and dialysate treated rats. The glycosaminoglycan modifications and collagen fibre increase seem to suggest that the morphological changes, with the features of fibrosis, could be the result of 2-ethylhexyl-phthalate and dialysate action on connective tissue. Moreover, the air pouch technique can be considered a good model for studying the direct effects of 2-ethylhexyl-phthalate and other substances, such as uremic toxins, on connective tissue.

Animals↗
PubMed2000

Tissue expander: histological and histochemical study 6 months after transplant--our experience.

Implanting an expander in the subcutaneous layer causes gradual expansion and provides additional tissue for reconstruction of tissular defects. The force applied remodels the connective tissue and modifies dermis contractibility in additional tissue. Other authors confirm that parameters such as mitosis and hyaluronan influence the system in the tissue regeneration processes. We studied histochemical and morphological variations of tissue expanders before and 6 months after transplant. Our histochemical data do not show any changes in dermis glycosaminoglycans of the expanded and transplant-expanded skin when compared to controls. Morphological data demonstrate reorganization of connective fibers and disappearance of the papillar layer. The latter is not yet formed in the expanded skin 6 months after transplant. This suggests that a long time is required for biological reconstruction of epidermal-dermal interactions after transplant.

Adolescent↗
PubMed1999

Urinary glycosaminoglycans in recurrent urinary tract infections in kidney transplant patients.

Glycosaminoglycans have generalized antibacterial anti-adherent activity, and cooperate with secretory immunoglobulin-A in anti-infection defense mechanisms of the urinary tract. Cyclosporin A modulates T-lymphocytes and fibroblast functions. In this report we analyze urinary glycosaminoglycans and secretory immunoglobulin-A in renal transplant patients with recurrent urinary tract infections treated with cyclosporin. The results show a significant decrease of total glycosaminoglycans and secretory immunoglobulin-A in recurrent urinary tract infections which is unrelated to cyclosporin treatment. The data support the hypothesis that recurrent urinary tract infections may be the consequence of a genetic pathology rather than cyclosporin-induced alterations.

Aged↗