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B Nusgens

Publications and source records attributed to B Nusgens.

At least 19 recordsLinked to original sources
PubMed2006

The in vitro influences of neurotensin on the motility characteristics of human U373 glioblastoma cells.

Astrocytic tumours are associated with dismal prognoses due to their pronounced ability to diffusely invade the brain parenchyma. Various neuropeptides, including gastrin, are able to modulate tumour astrocyte migration. While neurotensin has been shown to influence the proliferation of glioma cells and the migratory ability of a large set of other cell types, its role in glioma cell migration has never been investigated. Neurotensin-induced modifications to the motility features of human U373 glioblastoma cells therefore constitute the topic of the present study. We evidenced that three subtypes of neurotensin receptors (NTR1, NTR2 and NTR3) are expressed in U373 glioblastoma cells, at least as far as their mRNAs are concerned. Treating U373 tumour cells with 10 nM neurotensin markedly modified the morphological patterns of these cells and also profoundly altered the organization of their actin cytoskeletons. Pull-down assays revealed that neurotensin induced the activation in U373 cells of both Rac1 and Cdc42 but not RhoA. Scratch wound assays evidenced that neurotensin (0.1 and 10 nM) very significantly inhibited wound colonization by U373 cells cultured in the absence of serum. In addition, quantitative phase-contrast videomicroscopy analyses showed that neurotensin decreases the motility levels of U373 glioblastoma cells when these cells are cultured on plastic. In sharp contrast, neurotensin stimulates the motility of U373 cells when they are cultured on laminin, which is a pro-adhesive extracellular matrix component ubiquitously secreted by glioma cells. Our data thus strongly suggest that, in addition to gastrin, neurotensin is a neuropeptide capable of modulating tumour astrocyte migration into the brain parenchyma.

Actins↗
PubMed2005

Proanthocyanidins, from Ribes nigrum leaves, reduce endothelial adhesion molecules ICAM-1 and VCAM-1.

BACKGROUND: The effects of proanthocyanidins (PACs), isolated from blackcurrant (Ribes nigrum L.) leaves, on neutrophil accumulation during inflammatory processes were investigated in vivo and in vitro. METHODS: In vivo studies were performed using carrageenin-induced pleurisy in rats pre-treated with PACs. Exudate volume and PMNs accumulation were measured. Leukocyte cell adhesion molecules (LFA-1, Mac-1 and VLA-4) mobilization in circulating granulocytes were analysed by flow cytometry and endothelial cell adhesion molecules (ICAM-1 and VCAM-1) were detected by immunohistochemistry on lung sections. In vitro studies were conducted on endothelial LT2 cells, stimulated with TNF-alpha, to evaluate ICAM-1, IL-8 and VEGF mRNA expression upon PACs treatment. Data sets were examined by one-way analysis of variance (ANOVA) followed by a Scheffe post-hoc test. RESULTS: Pretreatment of the animals with PACs (10, 30 and 60 mg/kg) inhibited dose-dependently carrageenin-induced pleurisy in rats by reducing pleural exudate formation and PMNs infliltration. Leukocyte cell adhesion molecules mobilization was not down-regulated on granulocytes by PACs. Immunohistochemistry on lung sections showed a decreased production of endothelial cell adhesion molecules. In vitro experiments demonstrated that PACs were able to significantly inhibit ICAM-1 but not IL-8 and VEGF165 mRNA expression. Moreover, VEGF121 mRNA expression was dose-dependently enhanced. CONCLUSION: This study provides evidence to support the anti-inflammatory activity of proanthocyanidins is related to an inhibition of leukocyte infiltration which can be explained at least in part by a down-regulation of endothelial adhesion molecules, ICAM-1 and VCAM-1 and that these compounds are capable of modulating TNF-alpha-induced VEGF transcription.

Journal Article↗
PubMed2004

Invasion and MMP expression profile in desmoid tumours.

Desmoid tumours are locally invasive soft tissue tumours in which beta-catenin mediated TCF-dependent transcription is activated. The role of soluble factors secreted by the myofibroblastic desmoid tumour, which could stimulate tumour invasiveness, was investigated. Using collagen gel invasion assays, the presence of factors stimulating invasion in desmoid conditioned media (CM) could be established. Since matrix metalloproteinases (MMPs) have been implicated in the process of tumoral invasion, the expression levels of the MMP family members were evaluated. Quantitative reverse transcription-PCR was used to determine the expression levels of MMP1, MMP2, MMP3, MMP7, MMP11, MMP12, MMP13, MMP14 and the inhibitors TIMP1, TIMP2 and TIMP3. Besides overexpression of MMP7, a known TCF-dependent target gene, a striking upregulation of the expression levels of MMP1, MMP3, MMP11, MMP12 and MMP13 in desmoid tumours, compared to unaffected fibroblasts from the same patients, was found. Treating the CM of desmoids with a synthetic and a physiologic MMP inhibitor reduced the invasion-stimulating capacity of the desmoid CM by approximately 50%. These results suggest the involvement of soluble factors, released by the desmoid cells, in stimulating invasion and implicate the MMPs as facilitators of invasion.

Culture Media, Conditioned↗
PubMed2002

Positron emission tomography (PET) evaluation of abdominal aortic aneurysm (AAA).

BACKGROUND: aneurysmal disease is associated with an inflammatory cell infiltrate and enzymatic degradation of the vessel wall. AIM OF THE STUDY: to detect increased metabolic activity in abdominal aortic aneurysms (AAA) by means of positron emission tomography (PET-imaging). STUDY DESIGN: twenty-six patients with AAA underwent PET-imaging. RESULTS: in ten patients, PET-imaging revealed increased fluoro-deoxy-glucose (18-FDG) uptake at the level of the aneurysm. Patients with positive PET-imaging had one or more of the following elements in their clinical history: history of recent non-aortic surgery (n = 4), a painful inflammatory aortic aneurysm (n = 2), moderate low back pain (n = 2), rapid (> 2;5 mm in 6 months) expansion (n = 4), discovery by PET-scan of a previously undiagnosed lung cancer (n = 3) or parotid tumour (n = 1). Five patients with a positive PET scan required urgent surgery within two to 30 days. Among the 16 patients with negative PET-imaging of their aneurysm, only one had recent non-aortic surgery, none of them required urgent surgery, only two had a rapidly expanding AAA, and in only one patient, PET-imaging revealed an unknown lung cancer. CONCLUSION: these data suggest a possible association between increased 18-FDG uptake and AAA expansion and rupture.

Aged↗
PubMed2001

Biochemical study of collagen in adult groin hernias.

BACKGROUND: Previous works have suggested that a defect in collagen fiber structure may play a role in inguinal hernia formation. These studies focused mainly on the rectus sheath or the skin, while only few reports dealt with the transversalis fascia. According to these findings and to our previous biomechanical and histological studies suggesting that a connective tissue pathology could play a role in the genesis of groin hernias, we performed a biochemical investigation of the collagen in the transversalis fascia and rectus sheath. MATERIALS AND METHODS: The samples were collected from 40 adult patients with uni- or bilateral hernias and from 20 control subjects without hernia (autopsies and organ donors). A constant area of tissue was taken by using a calibrator. The wet and dry weights per 100 mm(2) were determined and the total collagen concentration as well as its sequential extractibility in NaCl, acetic acid, and pepsin was measured. The ratios of alpha(1)/alpha(2) chains (I) and of type I/III collagen were assessed by polyacrylamide gel electrophoresis. RESULTS: Samples collected in the control and patient sheaths showed an increased wet weight per 100 mm(2) in the patients. The wet and dry weights per unit area were increased in the patient fascias. The collagen concentration was increased in the indirect hernias. The fascias from the direct hernias (DH) presented a significantly increased collagen extractibility after pepsin digestion (5.6%), when compared to the control fascias (2.6%). The extractibility was 3.4% in the nonherniated (NH) sides. The qualitative study (ratios alpha(1)/alpha(2) (I) and I/III collagen) showed no difference between the fascia groups. CONCLUSIONS: The significant increase of collagen extractibility with pepsin in the DH fascias and at a lesser degree in the NH fascias suggests that molecular alterations of collagen could be involved in the genesis of groin hernias. This connective tissue pathology would express preferentially its effects in the inguinal region, since we have observed no major difference between the rectus sheaths of controls and those of patients.

Adult↗
PubMed2000

Progression in MCF-7 breast cancer cell tumorigenicity: compared effect of FGF-3 and FGF-4.

The transforming properties of fibroblast growth factor 3 (FGF-3) were investigated in MCF7 breast cancer cells and compared to those of FGF-4, a known oncogenic product. The short form of fgf-3 and the fgf-4 sequences were each introduced with retroviral vectors and the proteins were only detected in the cytoplasm of the infected cells, as expected. In vitro, cells producing FGF-3 (MCF7.fgf-3) and FGF-4 (MCF7.fgf-4) displayed an amount of estrogen receptors decreased to around 45% of the control value. However, MCF7.fgf-3 cell proliferation remained responsive to estradiol supply. The sensitivity of the MCF7.fgf-4 cells, if existant, was masked by the important mitogenic action exerted by FGF-4. In vivo, the MCF7.fgf-3 and MCF7.fgf-4 cells gave rise to tumors under conditions in which the control cells were not tumorigenic. Supplementing the mice with estrogen had the paradoxical effect of totally suppressing the start of the FGF-3 as well as the FGF-4 tumors. Tumorigenicity in the presence of matrigel was similar for MCF7.fgf-3 and control cells and was increased by estrogen supplementation. Once started, the MCF7.fgf-4 tumors grew with a characteristic high rate. Remarkably, FGF-4 but not FGF-3, stimulated the secretion of vascular endothelial growth factor (VEGF165) without altering the steady-state level of its mRNA, suggesting a possible regulation of VEGF synthesis at the translational level in MCF7 cells. The increased VEGF secretion is probably involved in the more aggressive phenotype of the MCF7.fgf-4 cells while a decreased dependence upon micro-environmental factors might be part of the increased tumorigenic potential of the MCF7.fgf-3 cells.

Animals↗
PubMed2000

A full-UV spectrum absorbing daily use cream protects human skin against biological changes occurring in photoaging.

BACKGROUND: There is overwhelming evidence that exposure of human skin to ultraviolet radiations (UVR) leads to the development of cutaneous photoaging and eventually to neoplasia. This study was designed to evaluate in humans the protection afforded by a daily use cream containing a photostable combination of UVB and UVA absorbers (Uvinul N539, Parsol 1789 and Mexoryl SX) providing a continuous absorption through the entire UV spectrum, against damages induced by repeated daily exposure to solar simulated radiation (SSR). METHODS: Buttock skin of 12 healthy volunteers was exposed 5 days per week for 6 weeks to one minimal erythema dose of solar simulated radiation per exposure. The following parameters in treated and untreated skin were evaluated: erythema, pigmentation, skin hydration, skin microtopography, histology and immunochemistry, and collagen and metalloproteinase (MMP) mRNA levels. RESULTS: In SSR exposed unprotected skin sites, we observed melanization and changes in the skin hydration and microtopography. The epidermis revealed a significant increase in stratum corneum and stratum granulosum thickness. In the dermis, an enhanced expression of tenascin and a reduced expression of type I pro-collagen were evidenced just below the dermal epidermal junction. Although we were unable to visualize any change in elastic fibers in exposed buttock skin, a slightly increased deposition of lysozyme and alpha 1 antitrypsin on these fibers was observed using immunofluorescence techniques. Furthermore, types I and III collagen mRNA were slightly increased and a significant enhancement (up to 2.8-fold) of MMP-2 mRNA level was observed. The daily use cream was shown to prevent all these biological changes. CONCLUSION: Our results show in vivo that an appropriate full-UV spectrum product significantly reduces the solar-UV-induced skin damage, demonstrating the benefit of daily photoprotection.

Acrylates↗
PubMed1999

The influence of cortical perforations and of space filling with peripheral blood on the kinetics of guided bone generation. A comparative histometric study in the rat.

The aim of the present study was to evaluate the influence of cortical perforations and of peripheral blood addition in guided bone generation beyond the skeletal envelope in rats. A total of 30 isogenic adult rats were divided into 3 equal groups. In each rat, two hollow parallelipipedic titanium chambers were placed bilaterally on the calvaria after a periosteal skin flap was raised. While on the right sides (controls) the osseous surface was left intact and the chambers were empty, the cortical bone under the left-side chambers (test sites) was perforated with nine 0.8 mm-diameter holes (group I), or left intact but with the chambers filled with a clot of peripheral blood (group II). In group III, both procedures were combined in the test sites. The healing was assessed at 4, 8 and 16 weeks after surgery by histologic and computer-assisted histometric analysis. The results demonstrated a substantial augmentation of on average 141% (SD 18) of the skull's thickness after 16 weeks in the controls, indicating that a predictable bone formation can be achieved beneath completely occlusive barriers over a non-injured cortical layer. In all test groups, a significantly larger bone augmentation was observed after 16 weeks compared to the control sites 172.8% (SD 41.7) in group I (P < 0.05), 172.0% (SD 18.4) in group II (P < 0.05) and 221.5% (SD 42.3) in group III (P < 0.001), demonstrating that stimulating blood supply and bone forming cells access by cortical perforations and/or blood clot addition enhances de novo bone formation in this experimental model.

Animals↗
PubMed1999

Human periodontal ligament fibroblast behavior on chemically conditioned dentine: an in vitro study.

BACKGROUND: Chemical root conditioning is widely used in an attempt to improve the outcome of regenerative periodontal surgery, but its effect on connective tissue cell proliferation and biosynthetic activity has been poorly studied. The goal of the present study was to test in vitro the consequences of conditioning human dentine by citric acid or minocycline on the behavior of attached human periodontal ligament (HPDL) cells in terms of proliferation, protein synthesis and morphological appearance. METHODS: HPDL cells were seeded on powdered human dentine, either untreated or conditioned for 3 minutes with 3% citric acid or 2.5% minocycline HCI. Scanning (SEM) and transmission (TEM) electron microscopic observations were performed, and 3H-thymidine and 3H-proline incorporation tests were used to evaluate the proliferative and the biosynthetic activities. RESULTS: Cell spreading was already evident and the penetration of cytoplasmic processes into dentinal tubules were frequently observed on all dentine types after 2 hours of attachment. After 24 hours of incubation, citric acid conditioning promoted an intense spreading of the cells, while minocycline HCI conditioning induced the formation of a dense feltwork of cellular processes. HPDL fibrolasts adherent to both types of surface-conditioned dentine exhibited a significantly higher rate of proliferation (P<0.01) as well as a significantly higher level of total protein and of collagen synthesis (P<0.01) than on untreated dentine. CONCLUSIONS: These data suggest that during periodontal surgery a conditioning of the root surface by citric acid or by minocycline HCI could promote the attachment, the proliferation, and the biosynthetic activity of HDPL, prerequisites to periodontal regeneration.

Anti-Bacterial Agents↗
PubMed1999

In vitro stimulation of human gingival epithelial cell attachment to dentin by surface conditioning.

BACKGROUND: Chemical root conditioning is widely used to improve the outcome of regenerative periodontal therapies by favoring the attachment of the regenerated periodontal structures. Although the effect of root conditioning on periodontal mesenchymal cells is well documented, very little is known about its potential effect on the re-formation of the junctional epithelium, a crucial event for the protection of the wound. The goal of the present study was to test in vitro the consequences of dentin conditioning with citric acid or minocycline on the attachment kinetics and morphology of human gingival keratinocytes (HGK). METHODS: The attachment kinetics of HGK to samples of powdered human dentin (particle size 44 to 76 microm) were examined by use of 3H-labeled cells. The morphology of attached epithelial cells was then determined by scanning electron microscopy (SEM). RESULTS: When the initial adhesion kinetics of cells on untreated dentin were tested, the percentage of attached HGK proved to be dependent on the number of plated cells and the time of incubation (from 0 to 12 hours). Conditioning the dentin by 3% citric acid or by minocycline-HCl (at 0.01, 0.1, or 2.5%) significantly increased (P <0.005) keratinocyte attachment beyond 6 hours, without notable differences between the 2 substances at any concentration. The attachment kinetics of HGK preincubated for 24 hours by 10 microg/ml minocyline-HCl on untreated dentin was found to be similar to that observed for non-preincubated cells. These results are in agreement with the SEM observations: indeed, the surface conditioning of dentin significantly modified the morphology of attached HGK, whereas the preincubation of these cells with minocyline-HCl did not. CONCLUSIONS: These results suggest that minocycline-HCl does not exert a direct effect on human gingival epithelial cells. In contrast, conditioning the dentin by citric acid or by minocycline stimulates the attachment of HGK, which could lead to a rapid periodontal healing by favoring the re-formation of a junctional epithelium.

Anti-Bacterial Agents↗
PubMed1998

In vitro modulation of human gingival epithelial cell attachment and migration by minocycline-HCL.

Although the influence of tetracyclines on periodontal connective tissue cells has been the topic of many in vitro and in vivo studies, data regarding their effects on gingival epithelial cells are scarce. The present in vitro study was designed to examine the influence of minocycline, a semi-synthetic analog of tetracycline, on human gingival keratinocyte (HGK) attachment and migration. Attachment tests were performed with HGK prelabeled by tritiated amino-acids. Increasing concentrations of minocycline (10, 50, 100 micrograms/ml) in the medium produced no significant modification of cell adhesion kinetics compared to control conditions, except for 100 micrograms/ml which statistically significantly (p < 0.05) reduced the number of attached cells beyond 6 h. A 24-h cell preincubation in 10 micrograms/ml of minocycline did not alter the kinetics of HGK attachment. Scanning electron microscopic observations of attached HGK showed that the presence of 10 micrograms/ml of minocycline in the "attachment medium" induced the production of multiple filopodial extensions. Migration tests in Boyden chambers for 40 h demonstrated that HGK preincubation for 24 h in a 10 micrograms/ml minocycline-HCl solution increased significantly (p < 0.005) cell migration towards a gradient of fetal calf serum. The presence of 10 micrograms/ml of minocycline in contact with the keratinocytes in the upper compartment of the migration chambers also produced a significant (p < 0.005) result. In contrast, the presence of minocycline in the lower compartments did not produce any chemoattractive effect. Within the limits of their significance, these results suggest that, at concentrations not beyond 50 micrograms/ml, minocycline could fasten the periodontal wound coverage by epithelial cells and allow the normal reformation of a junctional epithelium.

Adolescent↗
PubMed1996

[Low intensity electromagnetic fields produce a wave of calcium in the fibroblasts].

Human fibroblasts display a Ca2+ wave after irradiation with an electromagnetic field (EMF) of low intensity (100 to 900 microT) as seen by LASER confocal microscopy and excitation of Fluo 3. The number of excited cells is proportional to the intensity of EMF between 100 and 900 microT. Cellular activation by a dialysable serum factor is required to induce the Ca2+ wave. It also depends on extracellular Ca2+ and active tyrosine kinases and phospholipase C gamma.

Calcium↗
PubMed1995

Extracellular matrix proteins and basement membrane: their identification in bovine ovaries and significance for the attachment of cultured preantral follicles.

Described in the present paper is the immunolocalization of the extracellular matrix proteins (e.g., fibronectin, collagen Types I and III) in the bovine ovary, with special attention to preantral follicles. In addition, we have shown, histochemically and ultrastructurally, that mechanically isolated bovine preantral follicles are surrounded by an intact basement membrane. After 24 h of culture in serum-free medium, only 20.4% of these follicles attached to a plastic substrate. We showed that covering the plastic with extracellular matrix proteins (i.e., fibronectin, collagen Type I and matrigel) significantly increased the percentage of attached follicles to 76.0, 65.2 and 80.4%, respectively, while laminin had no effect (18.6%). When preantral follicles were embedded within three-dimensional collagen gels, no loss of follicles was observed. Restoring surface interactions between preantral follicles and the extracellular matrix in vitro, either in a two- or a three-dimensional system, might be important for maintaining follicular viability and growth in the future.

Journal Article↗
PubMed1995

Investigation of the relationship between osteoporosis and the collagenase gene by means of polymorphism of the 5'upstream region of this gene.

Osteoporosis is a slowly progressing disease resulting from an imbalance between bone accretion and degradation. As interstitial collagenase is a key enzyme in the degradation of bone matrix, we investigated a possible relationship between the collagenase gene and osteoporosis. Analysis of an amplified genomic DNA fragment from -524 to +52 by denaturing gradient gel electrophoresis and sequencing allowed us to detect three dimorphic sites upstream of base -300, one of them leading to a BanI restriction site. None of the sites could be directly associated with osteoporosis. The allele frequencies of the three dimorphic sites were estimated. The interallelic ratios were high, thus providing new useful genetic markers for linkage analysis. When comparing these ratios in osteoporotic and nonosteoporotic subjects, no significant differences could be observed.

Adult↗
PubMed1995

Biochemical analysis of heterotopic ossification in spinal cord injury patients.

Heterotopic ossification (HO) represents a frequent complication in spinal cord injury (SCI) patients. Samples of HO taken from SCI patients were studied and compared to normal bone. We used a procedure of bone particle fractionation (according to their degree of mineralisation) which allowed us to establish a profile reflecting the metabolic remodeling of bone and to analyse the organic matrix of the newly synthesised tissue. In paraplegic patients, we noted that there was a large increase of the proportion of a degree of calcified bone in the HO as we had previously observed in cortical as well as in cancellous bone of the same patients. Based on aminoacid analyses, we observed in the newly synthesised organic matrix of HO a decreased proportion of hydroxyprolyl residues resulting either from an alteration of the prolyl hydroxylation or from the presence of an excess of non-collagen polypeptides. These results are similar to those seen in sublesional bone of the SCI patients. This study demonstrates that HO is a newly formed bone which has a high rate of turnover as is seen in growing bone. This must be taken into account for the treatment of the patients.

Adult↗