References of "Goffinet, Gerhard"
     in
Bookmark and Share    
Full Text
See detailChapter 3, The Integument : Morphology and Biochemistry
Compère, Philippe ULg; Jeuniaux, Charles; Goffinet, Gerhard ULg

in Forest, J.; von Vaupel Klein, J. C.; Schram, F. R. (Eds.) The Crustacea revised and updated from the Traité de Zoologie Vol 1 (2004)

Detailed reference viewed: 26 (3 ULg)
Peer Reviewed
See detailSoft tissue attachment formation at titanium abutments in humans: a new model
Rompen, Eric ULg; Domken, Olivier ULg; Lamy, Marc ULg et al

in Journal of Dental Research (2003, December), 82(Sp. Iss. C), 510

Detailed reference viewed: 90 (15 ULg)
Full Text
Peer Reviewed
See detailCharacterization of the primary sonic muscles in Carapus acus (Carapidae): a multidisciplinary approach
Parmentier, Eric ULg; Gennotte, Vincent ULg; Focant, Bruno et al

in Proceedings of the Royal Society B : Biological Sciences (2003), 270(1530), 2301-2308

Sound production in carapid fishes results from the action of extrinsic muscles that insert into the swim bladder. Biochemical, histochemical and morphological techniques were used to examine the sonic ... [more ▼]

Sound production in carapid fishes results from the action of extrinsic muscles that insert into the swim bladder. Biochemical, histochemical and morphological techniques were used to examine the sonic muscles and compare them with epaxial muscles in Carapus acus. Sonic fibres are thicker than red and thinner than white epaxial fibres, and sonic fibres and myofibrils exhibit an unusual helicoidal organization: the myofibrils of the centre are in a straight line whereas they are more and more twisted towards the periphery. Sonic muscles have both features of red (numerous mitochondria, high glycogen content) and white (alkali-stable ATPase) fibres. They differ also in the isoforms of the light chain (LC3) and heavy chain (HC), in having T tubules at both the Z-line and the A–I junction and in a unique parvalbumin isoform (PAI) that may aid relaxation. All these features lead to the expression of two assumptions about sound generation: the sonic muscle should be able to perform fast and powerful contractions that provoke the forward movement of the forepart of the swim bladder and the stretching and ‘flapping’ of the swim bladder fenestra; the helicoidal organization allows progressive drawing of the swim bladder fenestra which emits a sound when rapidly released in a spring-like manner. [less ▲]

Detailed reference viewed: 43 (8 ULg)
Full Text
Peer Reviewed
See detailComparative degradation rates of chitinous exoskeletons from deep-sea environments
Ravaux, J.; Zbinden, M.; Voss-Foucart, M. F. et al

in Marine Biology (2003), 143(2), 405-412

Hydrothermal vent environments, particularly those associated with the vestimentiferan Riftia pachyptila, are believed to be among the highest chitin-producing systems. In order to elucidate the chitin ... [more ▼]

Hydrothermal vent environments, particularly those associated with the vestimentiferan Riftia pachyptila, are believed to be among the highest chitin-producing systems. In order to elucidate the chitin cycle in these environments, we estimate the in situ chitin degradation rates of tube-worm exoskeletons. Our in situ experiments show that the tubes of Riftia are highly stable structures. Comparative measurements of the degradation rates of Riftia tubes and crab shells immersed at deep-sea vents show that the tubes would be degraded within 2.5 years, whereas the time for the total degradation of the vent crab (Bythograea thermydron) carapaces would not exceed 36 days. The importance of the microbial participation in this degradation was estimated for Riftia tubes. Based on previous work, we calculated chitin production by a population of Riftia tubes of about 750 g m(-2) year(-1) (763). From our in situ experiments, we estimated a microbial chitinolysis rate of about 500 g m(-2) year(-1) (496) (65% of the chitin produced). Exoskeletons containing beta-chitin appear more stable in natural environments than those containing alpha-chitin and would thus be less available as carbon and nitrogen sources. In contrast, isolated beta-chitin was hydrolysed faster than alpha-chitin during in vitro degradation experiments; for instance, Riftia beta-chitin was degraded about 3- to 4-fold faster than Bythograea alpha-chitin. A stabilization process by disulfide bonds of the proteins-chitin link, rather than the crystalline form of the chitin (alpha/beta), accounts for the resistance of Riftia tubes to enzymatic attacks. [less ▲]

Detailed reference viewed: 22 (0 ULg)
Full Text
Peer Reviewed
See detailPreparation of poly(D,L-lactide) nanoparticles assisted by amphiphilic poly(methyl methacrylate-co-methacrylic acid) copolymers
Gautier, Sandrine; Grudzielski, Nathalie; Goffinet, Gerhard ULg et al

in Journal of Biomaterials Science. Polymer Edition (2001), 12(4), 429-450

When co-precipitated with amphiphilic copolymers from DMSO, poly(D,L-lactide) (PLA) can be readily converted into stable sub-200 nm nanoparticles by addition of an aqueous phase, free of any polymeric ... [more ▼]

When co-precipitated with amphiphilic copolymers from DMSO, poly(D,L-lactide) (PLA) can be readily converted into stable sub-200 nm nanoparticles by addition of an aqueous phase, free of any polymeric stabilizers such as poly(vinyl alcohol) or Poloxamer. In this work, the ability of random poly(methyl methacrylate-co-methacrylic acid) copolymers (PMMA-co-MA) to stabilize PLA nanoparticles was demonstrated, and the properties of PLA/PMMA-co-MA nanoparticles were investigated. When co-precipitated with PMMA-co-MA, PLA was totally converted into nanoparticles using a polymer concentration in DMSO (Cp) below 17.6 mg ml(-1), and a PMMA-co-MA proportion above a critical value depending on the content of MA repeating units (X). For instance, the lowest PMMA-co-MA proportion required was 0.9 mg mg(-1) PLA for X = 12%, and 0.5 mg mg(-1) PLA for X = 25% (for C(PLA) = 16 mg ml(-1) DMSO). The nanoparticle diameter was essentially independent of X, the proportion of PMMA-co-MA, and the PLA molecular weight, except for oligomers for which the nanoparticle diameter was smaller. It decreased when the organic phase was diluted (126 +/- 13 nm for Cp = 17.6 mg ml(-1), and 81 +/- 5 nm for C(P) = 5.6 mg ml(-1)). The time-dependence of the stability and the degradation of PLA/PMMA-co-MA nanoparticles was discussed. One of the main advantages of this technique is the ability to control surface properties and to bring functional groups to otherwise non-functionalized PLA nanoparticles. To illustrate this, a conjugate of PMMA-co-MA25 and biotin was synthesized, and used to prepare biotinylated nanoparticles that could be detected by fluorescence and transmission electron microscopy after infiltration into ligatured rat small intestine. [less ▲]

Detailed reference viewed: 46 (5 ULg)
Full Text
Peer Reviewed
See detailMicroencapsulation Of Erythromycin And Clarithromycin Using A Spray-Drying Technique
Zgoulli, S.; Grek, V.; Barre, G. et al

in Journal of Microencapsulation (1999), 16(5), 565-71

Previous methods of microencapsulation are unable to process particles smaller than 100 microm without organic solvents or the use of multistep processes. The present study investigates the feasiblity of ... [more ▼]

Previous methods of microencapsulation are unable to process particles smaller than 100 microm without organic solvents or the use of multistep processes. The present study investigates the feasiblity of a one-step spray-drying process to microencapsulate erythromycin and clarithromycin, antibiotics known to have an unpleasant, bitter taste. Mixtures of clarithromycin (5% by weight) or erythromycin (30% by weight) with a biodegradable polymer were prepared and spray-dried under specific conditions of temperature and turbine speed. This process resulted in the microencapsulation of 80% of each drug as determined by high pressure liquid chromatography. Particle size ranged from 1 to 80 microm as determined by electron microscopy. These data show that microencapsulation of macrolides using a spray-drying technique is feasible. Spray-drying microencapsulation might be useful in the formulation of palatable oral suspensions of bitter tasting drugs. [less ▲]

Detailed reference viewed: 97 (19 ULg)
Peer Reviewed
See detailIn vitro stimulation of human gingival epithelial cell attachment to dentin by surface conditioning.
Van Heusden, Alain ULg; Goffinet, Gerhard ULg; Zahedi, Sharham et al

in Journal of Periodontology (1999), 70(6), 594-603

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 ... [more ▼]

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. [less ▲]

Detailed reference viewed: 35 (9 ULg)
Full Text
Peer Reviewed
See detailImmunocytochemistry of lipids : chemical fixatives have dramatic effects on the preservation of tissue lipids
Maneta-Peyret, Lilly; Compère, Philippe ULg; Moreau, Patrick et al

in Histochemical Journal (The) (1999), 31

Detailed reference viewed: 17 (0 ULg)
Peer Reviewed
See detailComparison between the Natural Postnatal Maturation and the Spermine-Induced Maturation of the Rat Intestine
Peulen, Olivier ULg; Pirlet, Christine; Klimek, Monique ULg et al

in Archives of Physiology & Biochemistry (1998), 106(1), 46-55

In the suckling rats, orally provided spermine induced structural and biochemical changes in the intestine, which are characteristics of the postnatal maturation. This induced maturation was compared to ... [more ▼]

In the suckling rats, orally provided spermine induced structural and biochemical changes in the intestine, which are characteristics of the postnatal maturation. This induced maturation was compared to that occurring spontaneously. Eight mumol spermine were administered orally once a day, for one or three days, to suckling rats which were 11 days old at the beginning of the experiment. The animals were killed 0, 2, 4, 6, 8, 10 hours or 3 days after the first treatment. Control rats from the same litter were treated in the same way but received only the vehicle. In order to complete the study of the naturally occurring maturation, another group of rats was killed when they were 12, 13, 15, 16, 17, 18, 19, 20, 21 or 30 days old. Animal and intestine weights were measured. Disaccharidase specific activity, and protein, DNA and RNA contents were estimated in the small intestine. Histological and ultrastructural aspects of the intestinal mucosa were examined. For all these parameters, the maturation induced by spermine ingestion appeared close to that occurring naturally at weaning. Consequently, dietary spermine induces all the morphological and biochemical modifications characterizing the intestinal postnatal maturation in the suckling rat suggesting a role of the polyamines in the naturally occurring processes. [less ▲]

Detailed reference viewed: 17 (4 ULg)
Peer Reviewed
See detailIn vitro modulation of human gingival epithelial cell attachment and migration by minocycline-HCL.
Van Heusden, Alain ULg; Nusgens, Betty ULg; Goffinet, Gerhard ULg et al

in Journal of Periodontal Research (1998), 33(6), 377-85

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 ... [more ▼]

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. [less ▲]

Detailed reference viewed: 41 (13 ULg)
Full Text
Peer Reviewed
See detailScintigraphic visualization of intrathecal liposome biodistribution.
Umbrain, V; D'Haese, J; Alafandy, M et al

in Acta Anaesthesiologica Scandinavica (1997), 41(1 Pt 1), 25-34

BACKGROUND: Liposomes containing local anaesthetics have been administered intrathecally and in the epidural space. Poor attention has been given to the pharmacokinetics of liposomes as drug carriers ... [more ▼]

BACKGROUND: Liposomes containing local anaesthetics have been administered intrathecally and in the epidural space. Poor attention has been given to the pharmacokinetics of liposomes as drug carriers. Therefore, we observed the biodistribution of liposomes after intrathecal injection in rats by scintigraphic imaging during 24 h. METHODS: We administered 99mTc-labeled multilamellar (MLV) and small unilamellar vesicles (SUV) of defined size and volume dispersities into the cerebrospinal fluid at the lumbar level. Those vesicles were free of contamination by radiolabeled colloids as visualized by light and electron microscopy and of neurotoxic products from phosphatidylcholine hydrolysis and peroxidation, both during the preparation process and after 24 h incubation in cerebrospinal fluid at 37 degrees C in vitro. RESULTS: SUV immediately diffused from the lumbar site of injection to the head and were cleared between 1 and 24 h after injection. MLV were cleared more slowly from the spinal space and appeared in the head region 1 h after injection where they accumulated up to 24 h. These differences were explained in terms of vesicle sizes and volumes. SUV with 0.05 micron diameters were rapidly absorbed into the blood through the arachnoid granulations. In contrast, particles larger than the upper size limit of the arachnoid granulations permeability (+/- 8 microns) could accumulate in the head with a slow elimination rate. CONCLUSION: This difference in clearance from the intrathecal space outlines the importance of defining the size of the liposomes, the distribution of a tracer or a drug inside the liposomal preparation, the chemical stability and the absence of toxic degradation products of liposome formulations before clinical use. [less ▲]

Detailed reference viewed: 5 (0 ULg)
Full Text
Peer Reviewed
See detail"Exolysosomes", Enzyme-Containing Vesicles in the Ecdysial Space of Molting Crabs
Compère, Philippe ULg; Bouchtia, Hicham; Thiry, Marc ULg et al

in Journal of Structural Biology (1997), 119(3), 247-59

Free vesicle-like bodies (VLBs) present in the ecdysial space of cuticle regions undergoing degradation during preecdysis of the Atlantic shore crab Carcinus maenas have been interpreted either as ... [more ▼]

Free vesicle-like bodies (VLBs) present in the ecdysial space of cuticle regions undergoing degradation during preecdysis of the Atlantic shore crab Carcinus maenas have been interpreted either as infectious organisms or as secretion structures associated with degradation of the old cuticle. Ultrastructural, cytochemical, and immunocytological investigations were performed to test these hypotheses and to see whether VLBs are peculiar to this crab species. Similar VLBs were systematically found in two other preecdysial crabs, Cancer pagurus and Macropipus puber. In Car, maenas, they originate during early premolt inside Golgi buddings and are often gathered into large vacuoles in epidermal cells. The histochemical azo-dye technique and a cerium-based cytochemical method revealed acid phosphatase activity in both the ecdysial space and the VLBs, while Feulgen's method and immunocytological labeling always failed to reveal any DNA or RNA in either the ecdysial space or the VLBs. We conclude that VLBs are not infectious organisms but "extracellular" cuticle-degrading organelles of lysosomal origin and propose to coin them "exolysosomes." [less ▲]

Detailed reference viewed: 34 (4 ULg)
Peer Reviewed
See detailUltrastructural Modifications in Cultured Fetal Quail Hepatocytes Exposed to Pesticides and Pcbs
Hugla, J. L.; Goffinet, Gerhard ULg; Kremers, Pierre ULg et al

in Ecotoxicology & Environmental Safety (1996), 34(2), 145-55

There is increasing interest in cultured hepatocytes as a tool for solving toxicological and pharmacological problems while reducing laboratory animal experimentation. In the present study, fetal ... [more ▼]

There is increasing interest in cultured hepatocytes as a tool for solving toxicological and pharmacological problems while reducing laboratory animal experimentation. In the present study, fetal hepatocytes from the Japanese quail (Coturnix coturnix japonica) were used as an in vitro alternative model for evaluating the effects of PCBs and various pesticide-type chemicals on cell ultrastructure. Major alterations were demonstrated. The most striking effects of toxicants were an increase in the number of cisternae of the rough endoplasmic reticulum (RER), various alterations of mitochondrial morphology, a decreased glycogen content, vacuolization of the cytoplasm, and the appearance of concentric membrane arrays (CMA's), also called myelin-like figures. Other changes were sometimes observed, such as altered cell junctions, an increased lipid content, deformations of the nuclei, or the appearance of crystalline structures. These ultrastructural modifications seem to be dose-dependent. The present in vitro findings are validated by similar observations previously made in vivo on Japanese quail. They confirm the effectiveness of this technique as a biomonitoring tool for the evaluation of environmental quality. Yet the multiplicity of possible toxic effects, even for xenobiotics of a same category, makes it necessary to screen additional indicators of toxicity, such as the detoxifying activity of monooxygenases. [less ▲]

Detailed reference viewed: 35 (13 ULg)
Full Text
Peer Reviewed
See detailEffects on Pcbs on Liver Ultrastructure and Monooxygenase Activities in Japanese Quail
Stouvenakers, Nadine ULg; Hugla, J. L.; Goffinet, Gerhard ULg et al

in Bulletin of Environmental Contamination & Toxicology (1996), 56(5), 839-46

Detailed reference viewed: 8 (0 ULg)
Peer Reviewed
See detailCytochemistry of the tergite epicuticle of Glomeris marginata (Villers) (MYRIAPODA, DIPLOPODA): preliminary experimental results
Compère, Philippe ULg; Defise, Stéphane; Goffinet, Gerhard ULg

in Mémoires du Muséum d'Histoire naturelle (Paris) - Acta Myriapodologica (1996), 169

Detailed reference viewed: 9 (4 ULg)