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Biomedical subjects

F Monier

Publications and source records attributed to F Monier.

16 recordsLinked to original sources
PubMed2006

[Coronary stents and anaesthesia: it is time to have national data].

We report 13 cases of coronary stent patients, undergoing a non cardiac surgery. Despite an heterogenous perioperative management of antiplatelet agents, none of these patients developed any significant complications. Recently, several case reports of postoperative drug eluting stent thrombosis have been reported. However, the actual incidence of this dramatic event is not known. This confirms the need to perform prospective studies or registries of patients with coronary stents undergoing non cardiac surgery, in order to propose evidence-based recommendations on perioperative antiplatelet management in such patients.

Aged↗
PubMed2000

Gelatinase isoforms in urine from bladder cancer patients.

Matrix metalloproteinases are involved in tumor invasion and metastasis in many types of human carcinomas, in leukocyte infiltration and inflammatory reactions. Three metalloproteinases with gelatinolytic activity were isolated from the urine of patients with untreated high grade bladder cancer or with functioning renal grafts (control). Urinary proteins were fractionated after concentration by continuous-elution SDS-polyacrylamide gel electrophoresis. Collected fractions were analyzed by gelatin zymography and Western blotting. The one-step purification process isolated the gelatinase species from crude urine samples: (1) a 72 kDa progelatinase A (MMP-2) and its actived 68 kDa form; (2) a 92 kDa progelatinase B (MMP-9); (3) a higher molecular weight (HMW) complex (115 kDa) which was identified as progelatinase B associated with lipocalin, NGAL. A similar marker profile was observed in bladder cancer tissues. The current study demonstrated the efficiency of continuous elution electrophoresis. It offered two main advantages: (1) the separation of latent from active gelatinase isoforms with no interference from the TIMPs and (2) the identification and isolation in a single step of large amounts of urine gelatinase species with both high recovery and significant specific activities. Continuous-elution electrophoresis can be used for correlation with clinical events of bladder cancer diagnosis and prognosis.

Blotting, Western↗
PubMed2000

Role of metalloproteases and inhibitors in the occurrence and progression of diabetic renal lesions.

Renal remodelling in hyperinsulinic/insulinopenic states is mediated by glucotoxicity, endothelial dysfunction and vascular and nephron collagen turnover. Hypertensive and renal links are renewed by renoprotective interventions of renin-angiotensin. Vasoactive peptide processing and vascular collagen deposition are under the tight control of two zinc metalloproteinase families that regulate vascular tone and trophicity: gluzincins (or vasopeptidases) are convertases of angiotensins, endothelins or atrial natriuretic factors; and metzincins or matrix metalloproteases (MMP, matrixins)] regulate vascular type IV collagen basement membrane proteolysis. Association of natural tissue inhibitors of MMPs, pharmacological inhibitors of vasopeptidases [either conventional (angiotensin-converting enzyme inhibitors) or innovative (omapatrilat)], together with synthetic MMP inhibitors, are currently screened to counteract vascular remodelling and renal scarring. Our studies focused on the 72 kDa (MMP-2) and 92 kDa (MMP-9) matrixin gelatinases and tissue inhibitors involved in basement membrane degradation and rebuilding. Three complementary settings were developed, allowing evaluations from basic to clinical stages. A leucocyte-endothelial transmigration model was designed for transcription and addressing of enzymes and inhibitors, in situ matrix degradation, and blockading by metalloprotease inhibitors (captopril). Insulin-resistant fructose-fed rats showed heavy proteinuria and glomerulosclerosis involving angiotensin II-dependent changes in renal gelatinases and inhibitors. Urinary gelatinolytic profiles from Type 2 diabetic patients with overt nephropathy were compared with those of normal first-degree relatives and age-matched healthy controls. Physiologically, MMP-9 was the primary urinary gelatinolytic enzyme. In Type 2 diabetic proteinuric patients, MMP-9 and MMP-2 releases were significantly increased in the absence of renin-angiotensin blockade, while first-degree relatives showed reduced gelatinase levels suggestive of a genetic control of renal matrix regulation prior to potential glycaemic dysregulation. These preliminary data suggest that local MMP/TIMP imbalance is involved in diabetic renal remodelling. Further studies are needed to define the redundancies and specificities of vasopeptidase and MMP inhibitors, differentiate the antihypertensive effect from target-organ protection, screen for innovative pharmacological compounds, and validate simple, efficient biological markers of renal fibrosis progression and the effect of anti-fibrotic therapeutic interventions.

Animals↗
PubMed1999

Expression and activation of matrix metalloproteinases in wounds: modulation by the tripeptide-copper complex glycyl-L-histidyl-L-lysine-Cu2+.

We investigated the expression and activation of matrix metalloproteinases in a model of experimental wounds in rats, and their modulation by glycyl-L-histidyl-L-lysine-Cu(II), a potent activator of wound repair. Wound chambers were inserted under the skin of Sprague-Dawley rats and received serial injections of either 2 mg glycyl-L-histidyl-L-lysine-Cu(II) or the same volume of saline. The wound fluid and the neosynthetized connective tissue deposited in the chambers were collected and analyzed for matrix metalloproteinase expression and/or activity. Interstitial collagenase increased progressively in the wound fluid throughout the experiment. Glycyl-L-histidyl-L-lysine-Cu(II) treatment did not alter its activity. Matrix metalloproteinase-9 (gelatinase B) and matrix metalloproteinase-2 (gelatinase A) were the two main gelatinolytic activities expressed during the healing process. Pro-matrix metalloproteinase (pro-form of matrix metalloproteinase)-9 was strongly expressed during the early stages of wound healing (day 3). In the wound fluid, it decreased rapidly and disappeared after day 18, whereas in the wound tissue, matrix metalloproteinase-9 expression persisted in the glycyl-L-histidyl-L-lysine-Cu(II) injected chamber until day 22. Pro-matrix metalloproteinase-2 was expressed at low levels at the beginning of the healing process, increased progressively until day 7, then decreased until day 18. Activated matrix metalloproteinase-2 was present in wound fluid and wound tissue. It increased until day 12, then decreased progressively. Glycyl-L-histidyl-L-lysine-Cu(II) injections increased pro-matrix metalloproteinase-2 and activated matrix metalloproteinase-2 during the later stages of healing (days 18 and/or 22). These results demonstrate that various types of matrix metalloproteinases are selectively expressed or activated at the various periods of wound healing. Glycyl-L-histidyl-L-lysine-Cu(II) is able to modulate their expression and might significantly alter wound remodeling.

Animals↗
PubMed1998

Long-term variability of serum lipoprotein(a) concentrations in healthy fertile women.

Lipoprotein(a) is a unique lipoprotein with atherothrombogenic properties. Although its blood concentration is mainly genetically determined, various factors exist which may cause variability. These may influence the clinical use of the results. We studied lipoprotein(a) biological variation by a rate nephelometric assay over a period of two years in a population of healthy fertile women. The study was performed in 12 volunteers, healthy subjects with various lipoprotein(a) concentrations, by monthly determinations during one year and a single determination one year later, together with measurements of total, high density lipoprotein and high density lipoprotein2 cholesterol, triglycerides and apolipoproteins A1 and B. The intra-individual variability of lipoprotein(a) ranged between 4 to 20%, with three subjects showing a coefficient of biological variation higher than 15%. In absolute terms, the difference between two determinations could represent 0.44 g/l or 50% of the mean value. This study suggests that physiological lipoprotein(a) variations should be taken into account for clinical purposes, especially in patients in need of thorough risk evaluation.

Adult↗
PubMed1997

Evaluation of serum glycated lipoprotein(a) levels in noninsulin-dependent diabetic patients.

OBJECTIVE: Serum Lp(a) levels are generally considered unaffected by non-insulin-dependent diabetes mellitus (NIDDM). However, high Lp(a) concentrations as well as an increased rate of nonenzymatic glycation of proteins may be involved in degenerative diabetic complications. DESIGN AND METHODS: We measured serum glycated Lp(a) levels in 17 NIDDM patients, as compared to 14 normoglycaemic controls. Glycated proteins were separated from nonglycated ones by boronate affinity chromatography, and specific proteins assayed by immunonephelometric methods in both fractions. RESULTS: The percentage of glycated Lp(a) was 1.5 +/- 0.4% (mean +/- SD) in the control group, and was significantly higher in NIDDM patients: 4.3 +/- 1.5% (p < 0.01). The basal level of Lp(a) glycation was lower than that of other proteins, particularly apo B (4.0 +/- 0.7%). By contrast, the variations of glycated Lp(a) levels were of greater amplitude (+ 187%) than those of glycated apo B (+ 67%). Glycated Lp(a) values were significantly elevated in patients with micro and macrovascular complications in comparison with uncomplicated patients. CONCLUSIONS: These results suggest that glycated Lp(a) may be considered a potentially interesting parameter in the pathophysiology of diabetic vascular complications.

Adult↗
PubMed1995

Epithelium-mesenchyme transition during neural crest development.

The neural crest is the organ system whose presence defines vertebrates. The onset of migration of neural crest cells is an archetypal epithelium to mesenchyme transition (EMT), and this event identifies the cell lineage. Little is known yet of the establishment of the neural crest, although the zinc finger gene Slug seems to be involved in specifying EMT competence. The details, especially the temporal order of events in neural crest EMT, vary between different species and between different axial levels, but several important features have emerged from observations in situ and experiments in vitro and in vivo. EMT seems to be strongly associated with decrease in cell-cell adhesion, and particularly with loss of N-cadherin on the surface of neural crest cells at the time of onset of migration. The related adhesion molecule T-cadherin is also present, but correlated changes have not yet been described, while the unrelated adhesion molecule N-CAM also declines on neural crest cells, but with a time course unrelated to EMT. The extracellular matrix is also important: EMT-related changes in matrix receptor (i.e. integrin) activity are recorded in avian crest cells, while the nature of the matrix itself changes in urodele amphibians. Changes in cell shape and in cell motility also occur at the time of EMT, consistent with changes in the cytoskeleton. These concerted changes can be triggered by TGF-beta family growth factors, of which dorsalin-I appears particularly important. These may act through pathways involving controlled alterations in phosphorylation to effect the complex of responses that make up EMT. Although much remains to be understood, the spatiotemporal definability of this system makes it a very useful model for studying EMTs in general.

Animals↗
PubMedDate not supplied

[Focalized matrix proteolysis and inflammation].

The zinc metalloproteinases (MMPs or matrixins) are capable of damaging most of the constituents of the extra-cellular matrix and the basement membrane. The matrix proteolysis is the result of an imbalance both in the turnover of these constituants and in the ratio of the tissue inhibitors of metalloproteinases (TIMPs) versus metalloproteinases. After a brief description of the nature and structure of MMPs and TIMPs, this article reports on recent progress concerning the intra and extra-cellular activation mechanisms of proenzymes (proMMPs) which bring into play a series of proteolytic activations involving different proteinase families. Two points are stressed: 1) the main sites of focalized matrix proteolysis regulation, illustrated in the cellular interaction of inflammation, and 2) the wide phenotypic variety of MMPs and TIMPs.

Amino Acid Sequence↗