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Biomedical subjects

B Pellat

Publications and source records attributed to B Pellat.

At least 37 records · Page 2Linked to original sources
PubMed1997

Morphometric analysis of collagen and elastic fibers in normal skin and gingiva in relation to age.

The morphometric parameters of the human gingival elastic fiber network were determined by image analysis and compared with human skin elastic fibers in relation to age. Similarly, collagen fibers were also investigated in both tissues. In this study, 47 healthy patients, 10-75 years old were studied for gingiva and another 50 patients in the same age range were included for skin biopsies. Three groups were compared: group 1 from the age of 10-24 years, group 2 from 25 to 49 years, and group 3 from 50 to 75 years. The diameters of the oxytalan fibers were invariable in both tissues, whatever the age considered. On the other hand, the diameters of elastic fibers increased regularly with age in the gingiva (P < 0.01) and in the skin (P < 0.01) between each age group. The area fraction occupied by the oxytalan fibers decreased significantly in both tissues (P < 0.01) for the skin and (P < 0.001) for the gingiva. The area fraction occupied by the gingival elastic fibers remained constant with age while the skin elastic fibers increased significantly with age between groups 2 and 1 (P < 0.01) and between groups 3 and 2 (P < 0.001). In the mid-dermis and in the mid-gingiva, the diameters of the collagen fibers increased strongly with age, between groups 2 and 1 (P < 0.01) and between groups 3 and 2 (P < 0.001). The area fraction occupied by the collagen bundles increased regularly with age in the mid-gingival (P < 0.05 between each age group), while a significant decrease was observed in the mid-dermis from the age of 50-75 years (P < 0.05). The results obtained contribute to a better understanding of some modifications which dermis and gingiva undergo with aging and provide data to perfect diagnosis and therapy in odontology and dermatology.

Adolescent↗
PubMed1997

Increased expression of gelatinases A and B by skin explants from patients with anetoderma.

The extent of alterations to the elastic fibre network in lesional skin areas of three patients with anetoderma was assessed by quantitative image analysis of tissue sections and compared with morphometric parameters from unaffected sites of the same individuals. In the anetodermic skins pre-elastic fibres were undetectable or extremely rare: the volume fraction (Vv%) occupied by these pre-elastic fibres was 0-0.3%, while in unaffected skins the Vv% occupied by pre-elastic fibres was 0.5-0.8%. A nearly complete absence of dermal elastic fibres in lesional skins from the three patients was evidenced (Vv% = 0.2-0.3%). Organ cultures were performed using explants from skin with or without anetodermic lesions to quantify the expressions of elastase-type proteinases. All tissues from anetodermic lesions expressed proforms of gelatinases A and B and the activated form of gelatinase A; their levels increased with the culture time. In comparison, enzymatic activities on oligopeptide substrates specific for leucocyte elastase and fibroblast plasma membrane-associated metalloelastase were not detected in the conditioned media of any explants at any time of culture from 1 to 5 days. Increased production of progelatinases A and B and activation of progelatinase A could be mainly responsible for the degradation of skin elastic fibres demonstrated in anetodermic skins.

Adult↗
PubMed1995

Histomorphometric parameters and susceptibility to neutrophil elastase degradation of skin elastic fibres from healthy individuals and patients with Marfan syndrome, Ehlers-Danlos type IV, and pseudoxanthoma elasticum.

The morphometric parameters of mid-dermal elastic fibres from the skin of four patients with Marfan syndrome, four patients with Ehlers-Danlos syndrome type IV (EDS IV), and two patients with pseudoxanthoma elasticum (PXE) were determined, and compared with those of healthy individuals of a similar age range. The volume fraction occupied by elastic fibres was significantly reduced in Marfan patients compared with normal controls, and this was independent of age. In contrast, it was significantly increased in PXE patients, whereas the volume fraction occupied by skin elastic fibres varied within the EDS IV group. Dermal elastic fibres from patients with Marfan syndrome, EDS IV and PXE are hydrolysed by human neutrophil elastase in a qualitatively and quantitatively different fashion from those from healthy individuals. Marfan syndrome and EDS IV dermal elastic fibres were found to be more resistant to hydrolysis by human neutrophil elastase, but PXE elastic fibres were hydrolysed at a rate similar to elastic fibres from control skin.

Adolescent↗
PubMed1995

Growth stimulation of human skin fibroblasts by elastin-derived peptides.

Elastin-derived peptides (kappa-elastin: kappa E, mean molecular mass: 75 kDa), either coated onto plastic dishes or added to culture media (0.26 to 1.33 nM) stimulated the growth of human skin fibroblasts (HSF) strains obtained from different donors and tested at different cell passages (4 to 12). Coated 44.4 micrograms/cm2 insoluble elastin (iE) exhibited the same action; coated iE or kappa E significantly modifies the HSF morphology: after 5-6 days of culture, HSF are more elongated, and at preconfluence state, formation of HSF clusters surrounding iE were observed. Increased 3H thymidine incorporation and proliferative effect of HSF by kappa E (1.3 to 2.2 fold as compared to control cells) was observed after a lag phase period which raised with initial HSF density. Optimal proliferative effect was obtained at kappa E 8.5 10(-10) M, a value close to the dissociation constant (kD = 2.7 10(-10) M) of kappa E to HSF. Valine-glycine-valine-alanine-proline-glycine (VGVAPG), but not valine-glycine-valine (VGV) or Valine-glycine-valine-valine-glycine-alanine (VGVVGA) also significantly stimulated, optimally at 7.0 10(-10) M, HSF proliferation. It was concluded that the stimulatory influence of elastin derived peptides on HSF proliferation was mediated through a binding to plasmalemmal receptor of HSF.

Adult↗
PubMed1994

Increased secretion of latent elastase activity following contact between human skin fibroblasts and elastin derived peptides.

Elastin-derived peptides were previously shown to influence human skin fibroblasts (HSF) chemotaxis and proliferation (Ghuysen et al., 1992). We report here that culturing HSF on kappa-elastin (kappa E) but not onto fibronectin (FN) enhanced the secretion of latent elastinolytic activity. The proteinase involved was identified as the 72 kDa gelatinase A. Moreover, HSF-kappa E as well as HSF-FN interactions modulated the secretions of Il1 induced expressions of elastinolytic activities.

Adolescent↗
PubMed1991

[Biological markers in periodontal disease].

Periodontal diseases are thought to occur in an episodic manner with periods of breakdown and remission. This phenomenon can differ from one site to another. Clinical indices are unable to provide useful information about disease activity, but certain biologic markers may reflect periods of breakdown of connective tissue component of the periodontium. Procaryotic markers were excluded because they are difficult to identify and the results were uncertain. Tissue breakdown factors within the gingival sulcus were examined. Some of these factors could be correlated with the active stages of disease. These include: mediators of inflammation, catabolic enzymes, and enzymes associated with tissue necrosis. Among the eucaryotic tissue components, one or several could be of use to the dentist to assay disease activity. These tests could conceivably be done without complex and expensive equipment and could offer a new diagnosis index, "the active site index."

Biomarkers↗
PubMed1991

[Effect of chlorhexidine on bacterial fibrinolytic and collagenolytic activity].

Destructive periodontal diseases are characterized by tissue breakdown partly mediated by various enzymes originating from bacteria and/or tissue. Collagen and fibronectin are two of the main substrates available for enzyme activity. Since chlorhexidine is largely used during and after periodontal therapy, we have investigated the effects of chlorhexidine upon some bacterial proteases. Our data indicate that chlorhexidine inhibits, on a dose-dependent manner, both fibronectin and collagen hydrolysis mediated by either bacteroides (porphyromonas) gingivalis or bacteroides intermedius. Thus, it might be hypothesized that a side from its bactericidal activity, chlorhexidine helps to prevent periodontal tissue destruction directly by enzyme inhibition.

Bacteroides↗
PubMed1990

[Proteolysis of the extracellular matrix in periodontal disease].

Maintenance of teeth in the alveolar ridges requires integrity of the tooth-gingiva attachment. The strength of this connection is due in part to the presence of collagen and fibronectin. The purpose of this study was to investigate factors capable of altering these two components. In both gingival explant culture extracts and fractions from bacteria associated with periodontal disease, enzyme activities against type I collagen and fibronectin were found.

Collagen↗
PubMed1989

A comparison of fibronectinolytic activities from several oral bacteria.

Fibronectinolytic activity from two Gram-positive microorganisms (Streptococcus mutans and Bacterionema matruchotii), and from three Gram-negative oral bacteria (Bacteroides intermedius, Bacteroides gingivalis and Haemophilus actinomycetemcomitans) were compared. 125I-labelled human plasma fibronectin (FN) was incubated either either with bacterial extracts or with concentrated culture medium samples and the patterns of FN-degradation products were determined by SDS-PAGE. Results to date have shown that Streptococcus mutans, Bacterionema matruchotii and Haemophilus actinomycetemcomitans were unable to degrade FN. On the other hand the Gram-negative Bacteroides intermedius and Bacteroides gingivalis were shown to contain Fn-degrading activity. The highest activity was found in the bacterial extracts of Bacteroides gingivalis. Inhibition assays demonstrated that fibronectinolytic activity of Bacteroides gingivalis occurred predominantly by cysteine proteinase(s) while that of Bacteroides intermedius by a common action of serine and cysteine proteinases.

Actinomycetaceae↗
PubMed1988

Fibronectin-degrading activity in human crevicular fluid, gingival explants culture medium and bacterial plaques.

125I-fibronectin was incubated with extracts having presumably a proteolytic activity. Plaque from children without gingivitis, plaque from adults with chronic periodontitis, human gingival fluid and pooled culture media of human gingival explants were studied. Proteolysis was usually faster with plaque from patients with adult periodontitis than with plaque from children without gingivitis and the inhibition tests showed that several enzymes were implicated in the process. For the culture medium of gingival explants, the electrophoretic profile of the digestion products of fibronectin was different and showed a decreased activity. Nevertheless the gingival fluid gave a very similar degradation to bacterial plaque. The sulcular content was able to assume enzymatic activity capable of destroying fibronectin. These sulcular activities could be important for bacterial colonisation of sulcular surfaces and perhaps also for fibronectin destruction of periodontal tissues.

Adult↗
PubMed1987

Endoscopic cystoduodenostomy of cysts of chronic calcifying pancreatitis: a report of 20 cases.

This paper reports on the technique and results of 20 endoscopic diversions into the duodenum of cysts complicating chronic pancreatitis in 19 patients. The procedure, performed safely on the condition of visualization of a compression of the duodenal wall by the cyst, was successful 18 times in 17 patients. Complications occurred in four patients: two with bleeding (resulting in the death of one patient), two perforations treated successfully, and one transient cholangitis. Long-term results (average = 20.7 months) in 13 patients who were followed more than 6 months were good nine times, fair three times, and bad in one case. Endoscopic cysto-digestive diversion appears as an interesting alternative to surgery in selected patients with chronic pancreatitis.

Adult↗
PubMed1975

[Lipids of the human gingiva].

Human normal gingiva showed a distribution of 2/3 of non phosphorylated lipids and 1/3 of phospholipids, as well as a prevalence of free fatty acids, triglycerides and esters of cholesterol in relatively high rate. An important quantity of phosphatidylcholines, of phosphatidylethanolamines and sphingomyelins was also noted. The other phospholipids were present but in smaller quantity. The participation of the phsopholipids in the keratinization process of the oral mucosa has been discussed.

Aged↗
PubMedDate not supplied

[Gingival fluid].

Explore the source record for details and available documents.

Gingival Crevicular Fluid↗