Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 39
Filtrar
Mais filtros











Base de dados
Intervalo de ano de publicação
1.
Nutr Cancer ; 65(5): 686-94, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23859036

RESUMO

According to our previous study suggesting that antioxidant properties of phytochemicals in the diet decrease glioma aggressiveness, we used a SUVIMAX-like diet ("Supplementation en VItamines et Minéraux AntioXydants") (enriched with alpha-tocopherol, beta carotene, vitamin C, zinc, and sodium selenite), adapted to rats. The present results showed that each of the antioxidants inhibited growth of glioma cells in vitro. When used in combination for in vivo studies, we showed a highly significant delay in the clinical signs of the disease, but not a statistical significant difference in the incidence of glioma in an Ethyl-nitrosourea (ENU)-model. The SUVIMAX-like diet decreased candidate markers of tumoral aggressiveness and gliomagenesis progression. The mRNA expressions of 2 common markers in human glioma: Mn-SOD (Manganese Superoxide Dismutase) and IGFBP5 (insulin growth factor binding protein) were reduced in the tumors of rats fed the antioxidant diet. In addition, the transcripts of two markers linked to brain tumor proliferation, PDGFRb (platelet-derived growth factor receptor beta) and Ki-67, were also significantly decreased. On the whole, our results suggest a protective role for antioxidants to limit aggressiveness and to some extent, progression of gliomas, in a rat model.


Assuntos
Antioxidantes/farmacologia , Neoplasias Encefálicas/prevenção & controle , Etilnitrosoureia/toxicidade , Animais , Ácido Ascórbico/farmacologia , Neoplasias Encefálicas/induzido quimicamente , Proliferação de Células/efeitos dos fármacos , Feminino , Glioma/induzido quimicamente , Glioma/prevenção & controle , Proteína 5 de Ligação a Fator de Crescimento Semelhante à Insulina/genética , Proteína 5 de Ligação a Fator de Crescimento Semelhante à Insulina/metabolismo , Antígeno Ki-67/sangue , Masculino , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos , Receptor beta de Fator de Crescimento Derivado de Plaquetas/metabolismo , Selenito de Sódio/farmacologia , Superóxido Dismutase/genética , Superóxido Dismutase/metabolismo , Zinco/farmacologia , alfa-Tocoferol/farmacologia , beta Caroteno/farmacologia
2.
Oncogene ; 26(34): 4999-5009, 2007 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-17369862

RESUMO

Prostaglandin E(2) plays multiple roles both in the physiology and the physiopathology of human brain, which are not completely understood. We have identified in a subset of human glioblastoma multiforme (GBM) tumors, the most common form of adult brain cancer, an increased expression of mPGES-1, the enzyme which catalyses the isomerization of PGH(2) into PGE(2) downstream of cyclooxygenase 2 (COX-2). The sensitivity of primary cultures of GBM to apoptosis was augmented by the overexpression of mPGES-1, whereas the knockdown of its expression by shRNA decreased the apoptotic threshold in vitro and stimulated tumor growth in vivo. Adding extracellular PGE(2) in the culture medium failed to reproduce mPGES-1 effect on the cell viability in vitro. However, the intracellular injection of PGE(2) induced a dose-dependent apoptosis in GBM cultures, which was dependent on the presence of Bax, a pro-apoptotic protein. We show that PGE(2) physically associates with Bax, triggering its apoptotic-like change in conformation and its subsequent association with mitochondria. Our results raise questions about the role of PGE(2) in the control of apoptosis and in its potential impact in central nervous system pathologies.


Assuntos
Apoptose , Neoplasias Encefálicas/metabolismo , Dinoprostona/biossíntese , Glioblastoma/metabolismo , Proteína X Associada a bcl-2/metabolismo , Animais , Neoplasias Encefálicas/mortalidade , Neoplasias Encefálicas/patologia , Linhagem Celular Tumoral , Dinoprostona/farmacologia , Glioblastoma/mortalidade , Glioblastoma/patologia , Humanos , Oxirredutases Intramoleculares/metabolismo , Masculino , Camundongos , Camundongos Nus , Prostaglandina-E Sintases , Taxa de Sobrevida , Proteína X Associada a bcl-2/química
4.
Cytokine ; 14(4): 243-6, 2001 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-11448126

RESUMO

On the basis of studies using the Min mouse model of colon carcinogenesis, we have recently proposed that a fibre-like food (short-chain fructo-oligosaccharides, sc-FOS) fermented in the colon may stimulate a mechanism of cancer immunosurveillance. In the present paper, we have investigated the expression of cytokines as potential effector molecules. Interleukin (IL-)4, IL-5, IL-13, IL-15 and interferon (INF)-gamma mRNAs were detected by a multi-probe ribonuclease protection assay in C57BL/6J and Min mouse colons. IL-15 mRNA expression was significantly amplified (P=0.01) by the sc-FOS-enriched diet in the colon of Min mice.


Assuntos
Colo/imunologia , Colo/metabolismo , Fibras na Dieta/administração & dosagem , Genes APC , Interleucina-15/biossíntese , Oligossacarídeos/administração & dosagem , RNA Mensageiro/biossíntese , Animais , Citocinas/biossíntese , Dieta , Interleucina-15/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Mutantes
5.
Gut ; 48(1): 53-61, 2001 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11115823

RESUMO

BACKGROUND: Dietary fibres have been proposed as protective agents against colon cancer but results of both epidemiological and experimental studies are inconclusive. AIMS: Hypothesising that protection against colon cancer may be restricted to butyrate producing fibres, we investigated the factors needed for long term stable butyrate production and its relation to susceptibility to colon cancer. METHODS: A two part randomised blinded study in rats, mimicking a prospective study in humans, was performed using a low fibre control diet (CD) and three high fibre diets: starch free wheat bran (WB), type III resistant starch (RS), and short chain fructo-oligosaccharides (FOS). Using a randomised block design, 96 inbred rats were fed for two, 16, 30, or 44 days to determine the period of adaptation to the diets, fermentation profiles, and effects on the colon, including mucosal proliferation on day 44. Subsequently, 36 rats fed the same diets for 44 days were injected with azoxymethane and checked for aberrant crypt foci 30 days later. RESULTS: After fermentation had stabilised (44 days), only RS and FOS produced large amounts of butyrate, with a trophic effect in the large intestine. No difference in mucosal proliferation between the diets was noted at this time. In the subsequent experiment one month later, fewer aberrant crypt foci were present in rats fed high butyrate producing diets (RS, p=0.022; FOS, p=0.043). CONCLUSION: A stable butyrate producing colonic ecosystem related to selected fibres appears to be less conducive to colon carcinogenesis.


Assuntos
Butiratos/metabolismo , Colo/metabolismo , Neoplasias do Colo/prevenção & controle , Fibras na Dieta/administração & dosagem , Animais , Azoximetano , Carcinógenos , Colo/patologia , Fermentação , Mucosa Intestinal/patologia , Oligossacarídeos/administração & dosagem , Ratos , Ratos Endogâmicos , Amido/administração & dosagem
6.
Biochem Biophys Res Commun ; 273(2): 411-6, 2000 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-10873619

RESUMO

The expression of bcl-2-related proteins has been shown to be a key element in tumoral malignancy. The degradation of the extracellular matrix (ECM) by specialized matrix metalloproteinases (MMPs) is another major step in tumor invasion and metastasis. We have examined, in a rat glioma cell line A15A5, the effect of the stable transfection of human bcl-2, bax and bcl-xl on MMPs expression. Using a zymographic assay, we found that all transfected cell lines expressed a gelatinase activity which is predominantly associated with MMP-9. In bcl-2 and bcl-xl transfected cells, the transcription of MMP-9 was decreased compared to that of control or bax transfected cells. In addition, in bax transfected A15A5, we observed a down regulation of TIMP-1, the inhibitor of MMP-9. These results suggest that the ratio between MMP-9 and its inhibitor TIMP-1 is tightly controlled in cells overexpressing bcl-2 related proteins (i.e., high ratio in bax transfected A15A5 and low ratio in bcl-2 transfected A15A5). However, MMPs secreted by bcl-2 transfected cells were still capable of hydrolyzing FasL present on human lymphocytes. Our results suggest that the expression of bcl-2 related proteins could participate in the regulation of MMP-9/TIMP-1 in gliomas.


Assuntos
Metaloproteinases da Matriz/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Animais , Apoptose , Proteína Ligante Fas , Glioma/genética , Glioma/metabolismo , Glioma/patologia , Humanos , Metaloproteinase 9 da Matriz/genética , Metaloproteinase 9 da Matriz/metabolismo , Metaloproteinases da Matriz/genética , Glicoproteínas de Membrana/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos , Inibidor Tecidual de Metaloproteinase-1/genética , Inibidor Tecidual de Metaloproteinase-1/metabolismo , Transfecção , Células Tumorais Cultivadas
7.
Carcinogenesis ; 20(10): 1953-6, 1999 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-10506110

RESUMO

We have previously shown that addition of short chain fructo-oligosaccharides (indigestible carbohydrates) to food prevented colon tumors in C57BL/6-Apc(Min/+) mice, a model for human colon cancer. As gut-associated lymphoid tissue was concomitantly developed, we suggested that the immune response generated by this food may interfere with carcinogenesis due to involvement of mucosal cells in the regulation of tissue homeostasis. In the present experiment, we tested whether T cell status may influence colon tumor formation in Min mice fed a food supplement of short chain fructo-oligosaccharides. Min mice depleted of CD4(+) and CD8(+) lymphocytes developed twice as many tumors as immunocompetent mice (0.8 as compared with 0.4, the mean number in 7-week-old Min mice when food supplementation began; P = 0.02). It is concluded that food supplementation with a substrate (a known prebiotic) fermented in the colon may stimulate a mechanism of immunosurveillance that would otherwise remain inefficient.


Assuntos
Neoplasias do Colo/imunologia , Carboidratos da Dieta/administração & dosagem , Frutose/administração & dosagem , Oligossacarídeos/administração & dosagem , Linfócitos T/imunologia , Animais , Camundongos , Camundongos Endogâmicos C57BL
8.
Cancer Res ; 57(2): 225-8, 1997 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-9000559

RESUMO

C57BL/6J-Min/+ mice, which are heterozygous for a non-sense mutation in the Apc gene, provide a model for both familial adenomatous polyposis and sporadic colon cancers. In our study, gut tumors and small intestine lymphoid nodules were counted in Min mice fed fiber-enriched diets for 6 weeks. Neither starch-free wheat bran nor resistant starch modified the number of tumors. However, short-chain fructo-oligosaccharides dramatically reduced the incidence of colon tumors and concomitantly developed gut-associated lymphoid tissue. Our experiment shows that short-chain fructo-oligosaccharides counteract advanced stages of colon carcinogenesis, possibly via stimulation of antitumoral immunity by modulation of the colonic ecosystem.


Assuntos
Neoplasias do Colo/prevenção & controle , Fibras na Dieta/farmacologia , Oligossacarídeos/farmacologia , Nódulos Linfáticos Agregados/efeitos dos fármacos , Lesões Pré-Cancerosas/prevenção & controle , Animais , Bifidobacterium/efeitos dos fármacos , Bifidobacterium/crescimento & desenvolvimento , Colo/imunologia , Colo/microbiologia , Neoplasias do Colo/imunologia , Feminino , Fermentação , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Oligossacarídeos/química , Nódulos Linfáticos Agregados/crescimento & desenvolvimento , Lesões Pré-Cancerosas/imunologia
9.
Cancer Res ; 56(23): 5506-12, 1996 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-8968108

RESUMO

During cancer progression, tumor cells interact with stromal cells. As a consequence, matrix metalloproteinases are produced that contribute to the degradation of the extracellular matrix. This study used coculture systems to investigate fibroblast interaction with three colon cancer cell lines isolated from a single patient. Cells from primary colorectal carcinoma, but not from corresponding liver or lymph node metastases, induced gelatinase B expression by fibroblasts of different tissue origin. Remarkably, direct cell-cell contact was required for this induction, which occurred at the pretranslational level (as revealed by Northern blot analysis) and was completely blocked by anti-beta1 integrin monoclonal antibody, but only partially blocked by anti-alpha5 or anti-alpha(v). Induction was also inhibited by cytochalasin D, staurosporine, or dexamethasone, suggesting the need, respectively, for an organized actin cytoskeleton, protein kinase C, and AP-1-driven gene transcription. Our data suggest that direct tumor-stromal cell contact is one inductive event involved in matrix metalloproteinase expression by stromal cells.


Assuntos
Carcinoma/secundário , Colagenases/biossíntese , Neoplasias do Colo/patologia , Fibroblastos/enzimologia , Metástase Neoplásica/patologia , Animais , Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais/farmacologia , Carcinoma/patologia , Comunicação Celular , Células Cultivadas , Técnicas de Cocultura , Colagenases/genética , Tecido Conjuntivo/enzimologia , Células do Tecido Conjuntivo , Citocalasina D/farmacologia , Citoesqueleto/efeitos dos fármacos , Citoesqueleto/fisiologia , Dexametasona/farmacologia , Indução Enzimática , Inibidores Enzimáticos/farmacologia , Proteínas da Matriz Extracelular/metabolismo , Genisteína , Humanos , Integrina beta1/imunologia , Integrina beta1/fisiologia , Isoflavonas/farmacologia , Queratinócitos/efeitos dos fármacos , Queratinócitos/enzimologia , Neoplasias Hepáticas/patologia , Neoplasias Hepáticas/secundário , Neoplasias Pulmonares/patologia , Neoplasias Pulmonares/secundário , Metaloproteinase 9 da Matriz , Camundongos , Camundongos Nus , Proteína Quinase C/antagonistas & inibidores , Proteína Quinase C/fisiologia , Estaurosporina/farmacologia , Fator de Transcrição AP-1/fisiologia , Células Tumorais Cultivadas
10.
J Cell Biochem ; 62(1): 40-9, 1996 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-8836874

RESUMO

Malignant cell transformation is generally accompanied by changes in their interactions with environing matrix proteins in a way to facilitate their migration and generate invasion. Our results show the binding of rat colon adenocarcinoma PROb cells to fibronectin strongly reduced when compared to normal rat intestine epithelial cells. This decrease was not due to the level of alpha(s)beta 1 integrins expressed at the surface of the cell line. However, beta 1- and alpha(s)-associated subunits appeared to be structurally altered as shown by immunoprecipitation followed by electrophoresis. Pulse chase experiments using 35S methionine evidenced differences in the biosynthesis of beta 1- and alpha(s)associated integrins: normal epithelial IEC18 cells required 16 h for maximal biosynthesis of the completely mature beta 1 subunit, while PROb cells did it within 4-6 h. Studies using endoglycosidases O, H, D, and N glycanase confirmed that the molecular weight alterations were due to abnormal glycosylation and suggested that alpha(s)beta 1 integrins of PROb cells could bear both mature complex and immature high mannose types while IEC18 cells borne only mature complex type oligosaccharidic chains. Treatment of both cell types with castanospermine, an inhibitor of N-glycosylation, reduced the differences observed in their adhesion to the fibronectin without significantly affecting beta 1 receptors expression at the cell surface. These results strongly suggest a role of the glycosylation of beta 1 receptors in the adhesion of rat colon adenocarcinoma PROb cells to fibronectin substrata.


Assuntos
Neoplasias do Colo/metabolismo , Fibronectinas/metabolismo , Integrina beta1/metabolismo , Animais , Adesão Celular/efeitos dos fármacos , Neoplasias do Colo/patologia , Células Epiteliais , Epitélio/metabolismo , Glicosilação , Indolizinas/farmacologia , Integrina beta1/biossíntese , Ratos , Receptores de Superfície Celular/metabolismo , Células Tumorais Cultivadas
11.
Artigo em Inglês | MEDLINE | ID: mdl-7621009

RESUMO

Streptococcus mutans mineralization was studied in vitro, with the use of various metastable calcium phosphate solutions, fluoride-containing or otherwise. Degeneration of bacteria always occurred before their mineralization. After complete mineralization of the cytoplasmic area, growth of crystals was observed both in length and in thickness within the extracellular environment. Composition of the calcifying medium was an essential factor in the S. mutans mineralization process. The present study shows that, contrary to carbonate and magnesium ions that prevent intra- and extracellular deposits, fluoride ions promote crystal growth in the above mentioned mediums. Clinical implications of the role of fluoride, at the plaque level, are foreseen.


Assuntos
Calcificação Fisiológica , Cálculos Dentários/microbiologia , Streptococcus mutans/metabolismo , Calcificação Fisiológica/efeitos dos fármacos , Cloreto de Cálcio/farmacologia , Fosfatos de Cálcio/metabolismo , Cristalização , Meios de Cultura , Cálculos Dentários/metabolismo , Fluoretos/farmacologia , HEPES/farmacologia , Organelas/efeitos dos fármacos , Fosfatos/farmacologia , Soluções/farmacologia , Streptococcus mutans/ultraestrutura
12.
Hybridoma ; 13(2): 143-6, 1994 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-8050779

RESUMO

The role played by phosphophoryn, one of the major noncollagenous proteins of dentin extracellular matrix, in the mineralization process has not been fully characterized. The purpose of our work was to produce monoclonal antibodies (MAbs) against dentin phosphophoryn and to test their reactivity with primary culture of odontoblasts. Dentin phosphophoryn (DPP) was extracted after the mechanical dissociation of teeth and dialyzed against guanidine and EDTA solutions followed by CaC1(2) precipitation. These extracts were characterized by SDS-PAGE and staining with Coomassie blue and Stains-All. After immunization of mice with these extracts, we produced MAb 7G4, which reacted with dentin phosphophoryn as revealed by Western blot. MAb 7G4 reactivity was tested against a primary culture of pig odontoblasts, revealing filaments specifically stained by the anti-DPP antibody. This antibody will be of great interest to study the mineralization process and dental pulp reaction after capping with various calcium phosphate materials.


Assuntos
Odontoblastos/imunologia , Fosfoproteínas/imunologia , Animais , Anticorpos Monoclonais , Western Blotting , Bovinos , Células Cultivadas , Polpa Dentária/imunologia , Fosfoproteínas/isolamento & purificação , Suínos
13.
Cell Biol Int Rep ; 16(12): 1237-45, 1992 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-1283839

RESUMO

Mixed cultures of fibroblasts with rat colon carcinoma cell lines were used to investigate the production of extracellular matrix glycoproteins. Tumoral cells were shown to influence their production in different ways depending on the cell clone (PROb cells which in vivo produce progressive tumors and REGb cells which produce regressive ones) but also on the relative proportions of stromal and tumoral cells. When fibroblasts were predominant, the REGb cells containing mixture produced higher levels of all protein studied as compared with the PROb cells containing system. When the situation was reversed in favor of tumoral cells, REGb cells containing cocultures still produced more fibronectin, laminin and undulin, but the difference with PROb ones was reduced. On the opposite, cocultures enriched with PROb cells made more entactin and SPARC and approximately equal amounts of tenascin.


Assuntos
Glicoproteínas/metabolismo , Animais , Adesão Celular , Moléculas de Adesão Celular Neuronais/biossíntese , Células Cultivadas/metabolismo , Colágeno/metabolismo , Proteínas da Matriz Extracelular/biossíntese , Fibroblastos/metabolismo , Fibronectinas/metabolismo , Laminina/metabolismo , Glicoproteínas de Membrana/metabolismo , Ratos , Ratos Endogâmicos , Tenascina , Células Tumorais Cultivadas/metabolismo
14.
Epithelial Cell Biol ; 1(4): 168-76, 1992 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-1307947

RESUMO

We examined the fibronectin-adhesive properties of clones from a rat colonic cell line exhibiting distinct tumorigenicity in a syngeneic host. These cells were originally selected on the basis of differential adhesion to plastic surfaces. The TR cell line, when injected subcutaneously, forms a tumour which grows progressively and gives off metastases, whereas the TS cell line forms a small tumour which regresses within a few weeks. The regression is largely mediated by immunological factors and involves a fibroblastic reaction. REGb, a clone from the TS subline, adhered better to fibronectin or RGDS tetrapeptide than did PROb, a clone from the TR subline. However, there was little binding to the RGD tripeptide with either clone. The degree of adhesion was dependent on time and substrate concentration. After 6 h of incubation, 38% and 55% respectively of PROb and REGb cells bound to plates coated with 10 micrograms/ml fibronectin. Adhesion of both clones to fibronectin was inhibited to various degrees when cells were preincubated with RGDS, GRGDS or GRADSPK peptides, whereas other synthetic peptides such as RGD, GRGD or GRGFSPK were ineffective. Binding experiments using 125I-labelled fibronectin showed 39,000 fibronectin receptor sites on REGb cells but only 17,000 on PROb cells. Flow cytometry analysis using both anti-alpha 5 and anti-beta 1 integrins showed more fibronectin receptor sites on REGb than on PROb cells. Both approaches were in accordance with the higher adhesiveness of the REGb clone to fibronectin.(ABSTRACT TRUNCATED AT 250 WORDS)


Assuntos
Fibronectinas/metabolismo , Células Tumorais Cultivadas/metabolismo , Células Tumorais Cultivadas/patologia , Adenocarcinoma/metabolismo , Adenocarcinoma/patologia , Adenocarcinoma/secundário , Sequência de Aminoácidos , Animais , Adesão Celular , Neoplasias do Colo/metabolismo , Neoplasias do Colo/patologia , Dados de Sequência Molecular , Transplante de Neoplasias , Oligopeptídeos/química , Oligopeptídeos/metabolismo , Ratos , Receptores de Fibronectina/metabolismo
15.
Biomaterials ; 12(8): 752-6, 1991 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-1665992

RESUMO

The use of synthetic calcium phosphate as bone substitute calls for the knowledge of the influence on adjacent cells. Effects on monocytes, macrophages, synovial cells and fibroblasts have been largely described in vivo and in vitro but few data are available as concerns osteoblast responses. The present experiments tested the activity of MC3T3-E1, ROS 17/2.8 and mouse calvaria cells cultured in the presence of hydroxyapatite powders. The three osteoblast-like cells were shown to phagocytoze the calcium phosphate particles. As a consequence, they exhibit reduced cell growth and alkaline phosphatase activity. This response was different when compared with other cell types. The osteogenetic function of osteoblastic cells could be involved in these specific effects of hydroxyapatite.


Assuntos
Fosfatos de Cálcio/química , Hidroxiapatitas/química , Osteoblastos/citologia , Células 3T3 , Fosfatase Alcalina/metabolismo , Animais , Contagem de Células , Diferenciação Celular , Divisão Celular , Células Cultivadas , Durapatita , Camundongos , Microscopia Eletrônica , Osteoblastos/enzimologia , Osteoblastos/ultraestrutura , Fagocitose , Fenótipo , Ratos
16.
Calcif Tissue Int ; 47(4): 251-5, 1990 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-1700736

RESUMO

Two fractions were separated from the proteins of the mineral compartment of bovine developing enamel on the basis of their affinity for the lectin concanavalin-A. A monoclonal antibody was prepared by the hybridoma technique against the Con-A-binding fraction. This antibody and a commercial polyclonal antibody against bovine serum albumin were used to examine the relationship between those proteins, serum albumin and alpha-2HS glycoprotein, two proteins concentrated within dentin and bone matrices. The Con-A-unbound fraction reacted with the anti-albumin antibody and the antibody against the Con-A-binding fraction recognized the alpha-2HS glycoprotein. These data fully support the presence of significant levels of proteins related to serum components in the mineral compartment of developing enamel matrix.


Assuntos
Proteínas Sanguíneas/análise , Proteínas do Esmalte Dentário/análise , Epitopos/análise , Animais , Anticorpos Monoclonais/imunologia , Proteínas Sanguíneas/imunologia , Bovinos , Concanavalina A/imunologia , Concanavalina A/metabolismo , Reações Cruzadas/imunologia , Proteínas do Esmalte Dentário/imunologia , Epitopos/imunologia , Albumina Sérica/imunologia , alfa-Macroglobulinas/imunologia
17.
J Biomed Mater Res ; 24(2): 165-77, 1990 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-2329113

RESUMO

An in vitro method is described to assess the influence of synthetic calcium phosphate powders on osteoblast activities. Human osteoblast cell cultures were established from iliac crest. MC3T3-E1, an established osteogenic cell line, was employed as a control. Scanning and transmission electron microscopic observations clearly demonstrated the internalization of particles of calcium phosphate by the two osteoblast cell populations. As a consequence to the phagocytotic process, RNA transcription and protein synthesis were stimulated, as indicated by the measurements of labeled uridine, leucine and proline uptakes. From these data, it is proposed that such an in vitro model, using one of the specific cell types involved in the tissue responses to implants, could be useful to assess the biological response at the cell-biomaterial interaction.


Assuntos
Materiais Biocompatíveis/farmacologia , Osso e Ossos/citologia , Fosfatos de Cálcio/farmacologia , Hidroxiapatitas/farmacologia , Fosfatase Alcalina/metabolismo , Aminoácidos/metabolismo , Animais , Osso e Ossos/efeitos dos fármacos , Osso e Ossos/metabolismo , Células Cultivadas , Humanos , Camundongos , Microscopia Eletrônica , Osteocalcina/metabolismo , Fagocitose
18.
J Biomed Mater Res ; 23(12): 1433-40, 1989 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-2621216

RESUMO

Gingival fibroblasts were cultured with four different calcium phosphate minerals (hydroxyapatite, whitlockite, beta-tricalcium phosphate, and octocalcium phosphate). 3H-thymidine incorporation into DNA and alkaline phosphatase specific activity were determined after different incubation periods. As a consequence of the phagocytosis of calcium phosphates crystals, we pointed out, compared to control, a stimulation of the rate of 3H-thymidine incorporation and sharp decreases in alkaline phosphatase activity. The magnitude of the alkaline phosphatase activity inhibition was observed to be increased with the solubility of the materials. We propose that the effects of calcium phosphates on alkaline phosphatase and 3H-thymidine incorporation could be calcium-mediated events, resulting from intracellular dissolution of phagocytized materials. We suggest that in vitro determination of 3H-thymidine incorporation and alkaline phosphatase activity, which are highly sensitive tests, could be involved in evaluation procedures of calcium phosphates biomaterials.


Assuntos
Fosfatase Alcalina/metabolismo , Fosfatos de Cálcio/farmacologia , DNA/biossíntese , Fibroblastos/efeitos dos fármacos , Timidina/metabolismo , Adulto , Fosfatos de Cálcio/metabolismo , Fibroblastos/enzimologia , Fibroblastos/metabolismo , Humanos , Hidroxiapatitas/farmacologia , Masculino , Fagocitose , Solubilidade , Fatores de Tempo
19.
Calcif Tissue Int ; 45(1): 20-6, 1989 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-2504459

RESUMO

The introduction of a synthetic calcium phosphate into a biological environment is likely to result in surface-mediated chemical events. On the basis of such an assessment, we studied the chemical changes occurring in the mineral after exposure of a synthetic hydroxyapatite ceramic to both in vivo (implantation in human) and in vitro (cell culture) conditions. A small amount of the material was phagocytized but the major remaining part behaved as a secondary nucleator as evidenced by the appearance of a newly formed mineral. Morphologically, the newly formed mineral appeared as tiny crystals precipitated and grown from the surface of the initial synthetic crystals. The density of the additional mineral increased from the periphery to the core of each biomaterial aggregate. Chemically, it was identified by IR spectroscopy as a carbonated apatitic mineral. We propose that the adsorption of biomolecules could inhibit precipitation, accounting for the increasing amount of precipitate from the periphery to the core of the aggregates.


Assuntos
Hidroxiapatitas/metabolismo , Adulto , Osso e Ossos/citologia , Osso e Ossos/metabolismo , Células Cultivadas , Matriz Extracelular/metabolismo , Matriz Extracelular/ultraestrutura , Gengiva/citologia , Gengiva/metabolismo , Humanos , Microscopia Eletrônica , Pessoa de Meia-Idade , Bolsa Periodontal/metabolismo , Próteses e Implantes , Espectrofotometria Infravermelho
20.
Artigo em Inglês | MEDLINE | ID: mdl-2475194

RESUMO

Two different models have been used to study enamel proteins: rodent incisors and bovine or porcine tooth germs. In the present experiment proteins were sequentially extracted from forming enamel of rat incisors and bovine tooth germs and examined using SDS-PAGE. The Coomassie-blue staining of amelogenins from both species revealed very similar patterns, which indicates a rather common processing, although developed at different rates. Non-amelogenin proteins behave differently when Concanavalin-A probing was used. Bovine non-amelogenins contain amido-black stainable proteins which are not recognized by lectin, contrary to rat enamel. If those proteins are albumin or albumin derived, as recently suggested, the observed discrepancy might be explained by the non enzymatic glycation known to occur on circulating albumin. In that case it would be a consequence of the use of adult rats in which circulating albumin is partly glycated versus bovine foetuses in which albumin would not be significantly glycated. Finally both species contain glycoproteins within non-amelogenins, which remain to be more precisely defined.


Assuntos
Proteínas do Esmalte Dentário/análise , Amelogênese , Animais , Bovinos , Proteínas do Esmalte Dentário/isolamento & purificação , Solubilidade do Esmalte Dentário , Eletroforese em Gel de Poliacrilamida , Feto , Ratos , Coloração e Rotulagem/métodos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA