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M F Harmand

Publications and source records attributed to M F Harmand.

35 records · Page 2Linked to original sources
PubMed1990

Osteoarthritis-related changes in human articular cartilage. An immunologic study.

We report the use of immunologic methods for detecting specific alterations in human osteoarthritic cartilage. Monoclonal antibodies with specificities for proteoglycans and link proteins have been used to define immunogenic sites in these molecules. We have identified 1 site in the protein core, 1 site in the link proteins, and another site that is common to both proteoglycan and link proteins, which are not modified in osteoarthritic cartilage. In addition, an antigenic determinant in link proteins that is altered in osteoarthritic cartilage has been identified. These results suggest that the structure of the ternary complex (hyaluronic acid binding region-link proteins-hyaluronic acid) could be altered in osteoarthritic cartilage. These modifications may be due to a genetic defect or to partial enzymatic degradation of these sites.

Aged↗
PubMed1990

Micromechanical spectroscopy of cartilage proteoglycans: hydration.

Proteoglycan subunits extracted from calf cartilage have been studied with a high resolving power mechanical spectroscopy: the Thermostimulated Creep (TSC). The influence of hydration on TSC spectra shows the existence of two types of bound water: the weakly bound water increases the inertia of proteoglycan and stiffens their structure; the strongly bound water is responsible to a compensation law indicating the existence of a resonance phenomenon at the physiological temperature. Because of the looseness of bonds in weakly bound water, an increase of the local pressure may induce, in vivo, a release of water in tissues. This hypothesis explains perfectly the role of a water pump of proteoglycans in cartilage.

Animals↗
PubMed1990

Study of the effect of the surface state on the cytocompatibility of a Co-Cr alloy using human osteoblasts and fibroblasts.

Cobalt-chromium-based alloys are widely used in oral and orthopedic implantology. Although they are relatively well tolerated, biological complications could occur which sometimes are due to the insufficient biocompatibility of the alloy. This study shows the effects of an alloy (Co (base), 28% Cr, 5.5% Mo, 1% Ni, 0.95% Si, 0.7% Fe, 0.65% Mn, 0.25% C), on differentiated human cells derived from an oral implantation site, specifically alveolar bone osteoblasts and gingival fibroblasts. The cytocompatibility of the alloy is determined by the study of cell proliferation, determination of total cell protein and intracellular alkaline phosphatase contents, cytoskeleton, and cell morphology. The alloy is presented to the cells in four different surface states: rough cast, specular polished, microbead blasted, and RF sputtered. The results demonstrate that the same material has different effects on the basal and specific cellular functions, according to its surface state. For this alloy we can classify its cytocompatibility according to its surface state in such an order: Microbead blasted much greater than specular polished greater than RF sputtered greater than rough cast.

Cell Division↗
PubMed1990

Corrosion protection of metal implants by hard biocompatible ceramic coatings deposited by radio-frequency sputtering.

Most metals used for orthopaedic and stomatology implants and prostheses belong to the families of titanium or nickel-based and cobalt-based superalloys designed for advanced technology industries (e.g. space, aeronautic and nuclear industries). Ideal materials should be as insoluble and biologically compatible as possible. In the present paper the corrosion behaviour of Ni-Cr and Co-Cr alloys in biological media is evaluated through potentiodynamic polarization tests. It is shown that these metals exhibit some minor release of the component elements and degradation products, which may induce cytotoxic and allergic effects. The corrosion resistance of these alloys can be strongly enhanced by hard ceramic coatings deposited by radio-frequency sputtering. The biocompatibility of coated and uncoated metals is compared from differentiated human cell cultures.

Chromium Alloys↗
PubMed1990

Fibrin seal in wound healing: effect of thrombin and [Ca2+] on human skin fibroblast growth and collagen production.

To assess the interaction of a fibrin sealant with wound healing, an in vitro study using human skin fibroblasts was carried out. The effect of thrombin and calcium concentrations in the sealant on the growth parameters and collagen synthesis by normal human skin fibroblasts was examined. The fibroblast proliferation was increased 3 times for 50 and 25 IU of thrombin/ml. However for 20 mM [Ca2+], this stimulating effect of thrombin was observed after an 8 day incubation period, whereas it was observed as soon as the 2nd day in the presence of 2 mM [Ca2+]. The high rate of [Ca2+] (20 mM) partly inhibited DNA synthesis: for 2 mM [Ca2+], the incorporation of [3H]-Thymidine was 4 times greater than for 20 mM [Ca2+]. Further experiments demonstrated that human skin fibroblasts in the presence of 50 IU of thrombin/ml and 2 mM [Ca2+] in fibrin seal could increase the type I and III collagen synthesis while increasing the ratio of type III to type I. Thus, our results suggest that in vivo wound healing which required fibroblast growth and collagen synthesis can be stimulated in the presence of fibrin glue which is in good accordance with previous clinical observations.

Calcium↗
PubMed1990

Biochemical analysis of normal and osteoarthritic human cartilage.

Non-collagenous proteins from the articular cartilage of normal subjects and patients with degenerative joint disease were extracted sequentially. Proteoglycans and the other glycoproteins were more extractable from the osteoarthritic cartilage at lower ionic strength than those from the normal cartilage. A 50-kD protein which seems specific to osteoarthritic cartilage was identified. Three different populations of proteoglycans were purified from normal and only two from osteoarthritic cartilage. Moreover, greater amounts of albumin and fibronectin were found in the pathological cartilage. No differences were observed between link proteins from normal and osteoarthritic cartilage, nor in their molecular weight or the amounts extracted.

Blotting, Western↗
PubMed1990

Characterization of interfaces in human calcified tissue.

Thermostimulated current spectroscopy has been applied to the investigation of molecular mobility in human calcified tissue. A comparative study of extracts at various stages of demineralization is presented. The response of an organic-mineral complex interphase has been identified.

Adult↗
PubMed1989

Problems in the immunolocalization of type IX collagen in fetal calf cartilage using a monoclonal antibody.

Monoclonal antibodies were prepared against the pepsin-resistant fragments (X1-X3) of bovine type IX collagen. One of the five hybridomas that gave a positive reaction in an enzyme-linked immunosorbent assay was selected (H1a) for structural analysis and immunolocalization of type IX collagen. The location of the epitope for H1a was deducted from immunoblots and electron microscopic observations after rotary shadowing. The H1a antibody binds to one end of the longest X2, X3, X4 molecules, and preferentially 40-55nm from one end of X1 molecules thus, on or near the noncollagenous domain, NC2. Different immunolocalizations of type IX collagen in the superficial, middle and deep zones of fetal calf epiphyseal cartilage were observed depending on the thickness of the section and on hyaluronidase digestion conditions. In the middle and deep zones, staining with H1a throughout the matrix was obtained only with thin sections (5 microns) and digestion for 1 h at 37 degrees C. With thick sections (15 microns) or with digestion for 1 h at 24 degrees C, staining was restricted to the pericellular regions. Staining throughout the matrix was obtained in the superficial zone under all experimental conditions. Without hyaluronidase treatment, no immunofluorescent staining was seen with either H1a or polyclonal antibody to type II collagen, indicating that type IX collagen is present throughout the matrix in the different zones of fetal calf cartilage. This result is in good accordance with the recent demonstration of common cross-links between type II and type IX collagen in chicken and bovine cartilage. However, the preferential unmasking of type IX collagen antigenic sites in the pericellular regions of middle and deep zones of fetal calf cartilage does not preclude the presence in that region of a special pericellular organization of the collagenous network.

Animals↗
PubMed1989

Ex-vivo study of molecular interfaces in calcified tissues.

The aim of this work is the characterization of interfaces in calcified tissues. Thermally Stimulated Currents and Gel Permeation Chromatography have been used for investigating extracts and residues from calf femoral diaphysis, at various stages of demineralization. In residues, the evolution of molecular mobility shows that the organic-mineral linkage is insured by several proteins: Collagen is not directly linked to apatite.

Animals↗
PubMed1989

Phospholipase A2 activity in human osteoarthritic cartilage.

Phospholipase A2 (PLA2) activity was measured in articular cartilage from normal and osteoarthritic (OA) human femoral heads. Protoglycanase and collagenase activity was determined in the same specimens using radiolabelled human proteoglycan subunit and type II collagen, respectively. Grossly normal and fibrillated OA cartilage samples showed a significant increase in PLA2 activity which was not found in osteophytic cartilage. PLA2 activity was found to be correlated with proteoglycanase but unrelated to collagenase activity. Tiaprofenic acid induced in vitro a concomitant increase in PLA2 and a decrease in proteoglycanase activity. PLA2 which may be activated by cytokines as well as mechanical factors is suggested as a key enzyme in chondrocyte metabolism regulation. Tiaprofenic acid is shown as a potential chondroprotective nonsteroidal anti-inflammatory drug.

Aged↗
PubMed1987

Effects of S-adenosylmethionine on human articular chondrocyte differentiation. An in vitro study.

The effect of S-adenosyl-L-methionine (SAMe) on human articular osteoarthritic chondrocytes was studied using a thick-layer culture model. Three SAMe concentrations were tested (1, 10, and 100 micrograms/ml). For 10 micrograms/ml, the most efficient dose, a significant rise in the incorporation levels of 35S-sulfate and 3H-serine was observed, as was as an increase in the hexuronic acid content. All the parameters seem to express a more active protein synthesis, particularly for proteoglycans. Under the same conditions, the proliferation rate of chondrocytes does not undergo important variations. These results point to a direct action on the cell metabolism but little is known concerning the mechanism involved.

Cartilage, Articular↗
PubMed1984

In vitro stimulation of articular chondrocyte differentiated function by 1,25-dihydroxycholecalciferol or 24R,25-dihydroxycholecalciferol.

The effects of 1,25-dihydroxycholecalciferol (1,25-(OH)2D3) (10(-13)M-10(-8) M) and 24R ,25-dihydroxycholecalciferol ( 24R ,25-(OH)2D3) (10(-12)M-10(-7) M) on cell proliferation and proteoglycan deposition were examined in our newly developed multilayer culture system for rabbit and human articular chondrocytes. The cells are embedded in an extracellular matrix similar to that seen in vivo and maintain their in vivo phenotype. We extracted and purified native proteoglycans and degraded material from three culture compartments: the medium, intercellular matrix, and cells. Proteoglycan synthesis and deposition were analyzed by measuring 35SO4 incorporation, hexuronic acid, and galactose contents. In both rabbit and human chondrocyte cultures, chronic 1,25-(OH)2D3 treatment inhibited chondrocyte proliferation and stimulated proteoglycan synthesis and accumulation in the three compartments at 10(-12)-10(-8) M; maximal effect was at 10(-10)M. Cell proliferation was reduced by 55% and the content of hexuronic acid (or galactose) was increased to about three times that of controls in all compartments. 1,25-(OH)2D3 did not alter the proteoglycan composition. Chronic 24R ,25-(OH)2D3 treatment induced comparable effects with a maximum at 10(-8)M. When human dermal fibroblasts were treated as above both vitamin D metabolites increase mitosis. 1,25-(OH)2D3 mainly reduced the pericellular deposition of proteoglycans, while 24R ,25-(OH)2D3 appeared to reduce their synthesis and deposition in both medium and pericellular compartments. These results suggest that both 1,25-(OH)2D3 and 24R ,25-(OH)2D3 act specifically on articular chondrocytes to promote phenotype expression.

Animals↗
PubMed1982

Proteoglycan synthesis in chondrocyte cultures from osteoarthrotic and normal human articular cartilage.

Chondrocytes derived by outgrowth from normal and osteoarthrotic human femoral head cartilage were grown in high density cultures for five passages. Cultures were analysed for their sulfated macromolecular components in medium, layer-matrix and intracellular compartments. Two fractions were obtained: typical proteoglycans and glycosaminoglycan-peptides (Mr approx. 60 000) which might result from an enzymatic degradation of proteoglycans. Proteoglycans from normal and osteoarthrotic cultures exhibited similar biochemical properties (size, protein:uronic acid ratio, glycosaminoglycan composition). Slightly less proteoglycans were aggregated with hyaluronic acid in osteoarthrotic than in normal cultures. Three populations of proteoglycan subunit were obtained under dissociative conditions (Sepharose CL-2B) in both normal and osteoarthrotic cultures: proteoglycan 1 (Kav=0.04), proteoglycan 2 (Kav=0.26) which were aggregated with hyaluronic acid in associative conditions, and proteoglycan 4 (Kav=0.48). A fourth population, proteoglycan 3 (Kav=0.33, Sepharose 2B and CL-2B) was intracellular in osteoarthrotic cultures. After a 4 day incubation period, about 60% more proteoglycans were found in osteoarthrotic than in normal cultures (medium+52%, layer-matrix + 44% and 17 times the normal value inside the cells). Proteoglycan distribution kinetics in the three compartments showed a higher net accumulation of proteoglycans in osteoarthrotic-derived cultures.

Carbohydrates↗
PubMed1981

15-(p[75Br]bromophenyl)pentadecanoic acid: pharmacokinetics and potential as heart agent.

Preparation, quality control, and pharmacokinetics of 15-(p-[75Br]bromophenyl)pentadecanoic acid (BPPA) were studied, with particular emphasis on the fate of the label and the usefulness of BPPA as a heart agent. BPPA labeled with the positron emitter Br-75 (T 1/2 = 98 min) was prepared in 55% radiochemical yield with a specific activity of greater than or equal to 1000 Ci/mmol. While the uptake of BPPA in the heart muscle is as fast and efficient as that of aliphatic omega-halofatty acids, its elimination is delayed, owing mainly to an inhibited beta oxidation and the formation of lipophilic catabolites. The blood activity and its time course are identical to those of omega-halofatty acids, but no free bromide appears in any body fluid or organ. The complex pharmacokinetic behavior of stable lipophilic catabolites prevents a quantitative background correction. In contrast to aliphatic omega-halofatty acids, a quantitative evaluation of myocardial metabolism is not possible. Br-75 BPPA, however, is well suited for positron emission tomography of the heart.

Animals↗
PubMedDate not supplied

Pharmacokinetics and metabolism of [35S]-Thiazolidine carboxylic acid in the rat. I. Elimination and distribution.

The localization and elimination of 35S-Thiazolidine carboxylic acid has been studied in rats following a single oral dose (100 mg/kg) and multiple oral doses (100 mg/kg/day) over 15 days. The compound was rapidly and completely absorbed as evaluated by the time of the maximum plasma 35S-concentration (140 micrograms eq/ml at 30 min) and the amount of radioactivity in the feces (less than 1% of the dose over 48 h). Urinary excretion seems to be the unique route of elimination. There was specific tissue accumulation of drug or metabolite, particularly in liver (29% of the dose at 3 h), pancreas (7% of the dose at 3 h), adrenals (320 micrograms eq/g at 3 h), pituitary and thyroid (230 micrograms eq/g at 3h). Fixation of radioactivity appears significantly higher after chronic treatment than after acute treatment.

Animals↗