Using Biomaterials to Reduce Fibrous Encapsulation of Biomedical Implants

Fibrous encapsulation, commonly referred to as scar formation, can cause failure in many biomedical implants, such as in the artificial pancreas for type I diabetes treatment. Scar tissue prevents wastes and nutrients from being able to be exchanged in the implant, ultimately rendering the treatment painful or ineffective. For example, one potential therapeutic for type I diabetes involves using a polymer to protect insulin-producing cells. This artificial pancreas provides diabetics with their much needed insulin on-demand. If scar tissue forms around this artificial pancreas, the device loses the ability to deliver insulin and becomes useless. Our goal is to reduce the fibrous encapsulation of implants using biomaterials and improve the understanding of how cells involved in scar formation respond to biomaterials. We show that our materials can reduce fibrous capsule formation by inhibiting certain physiological pathways. This research will not only improve the success of the artificial pancreas, but other biomaterials

Influence of Lysine-Based Biomaterials on Fibroblast to Myofibroblast Differentiation

Fibrous encapsulation occurs as a result of implantation of devices such as pacemakers, artificial breast implants, and microencapsulated islet cells used in type 1 diabetes treatment. The foreign body response (FBR) is responsible for the development of a fibrous capsule, which is often detrimental to the function of the implanted device and therefore affected patients. One event leading to fibrous capsule formation is contraction of collagen by myofibroblasts. The objective of this project was to significantly reduce the thickness of the fibrous capsule by limiting fibroblast to myofibroblast differentiation. It was hypothesized that using lysine-based biomaterials with amidine-like functional group modifications would inhibit matrix metalloproteinase (MMP) activity, a precursor to myofibroblast formation. MMP Inhibition would impede cleavage of latent transforming growth factor beta (L-TGF-β) to transforming growth factor beta (TGF-β), a cytokine that stimulates fibroblast to myofibroblast differentiation. Cell staining was performed on NIH 3T3 fibroblasts cultured on each biomaterial and stimulated by L-TGF-β and TGF-β to evaluate material performance. Fibroblast viability was found to be \u3e70% on each material. These biomaterials have potential for use as a coating of microencapsulated islet cells for diabetes therapy. This study is also important for furthering understanding of the biology involved in fibrous capsule formation

Using Biomaterials to Reduce Fibrous Encapsulation of Biomedical Implants

Fibrous encapsulation, commonly referred to as scar formation, can cause failure in many biomedical implants, such as in the artificial pancreas for type I diabetes treatment. Scar tissue prevents wastes and nutrients from being able to be exchanged in the implant, ultimately rendering the treatment painful or ineffective. For example, one potential therapeutic for type I diabetes involves using a polymer to protect insulin-producing cells. This artificial pancreas provides diabetics with their much needed insulin on-demand. If scar tissue forms around this artificial pancreas, the device loses the ability to deliver insulin and becomes useless. Our goal is to reduce the fibrous encapsulation of implants using biomaterials and improve the understanding of how cells involved in scar formation respond to biomaterials. We show that our materials can reduce fibrous capsule formation by inhibiting certain physiological pathways. This research will not only improve the success of the artificial pancreas, but other biomaterials.</p

Influence of Lysine-Based Biomaterials on Fibroblast to Myofibroblast Differentiation

Fibrous encapsulation occurs as a result of implantation of devices such as pacemakers, artificial breast implants, and microencapsulated islet cells used in type 1 diabetes treatment. The foreign body response (FBR) is responsible for the development of a fibrous capsule, which is often detrimental to the function of the implanted device and therefore affected patients. One event leading to fibrous capsule formation is contraction of collagen by myofibroblasts. The objective of this project was to significantly reduce the thickness of the fibrous capsule by limiting fibroblast to myofibroblast differentiation. It was hypothesized that using lysine-based biomaterials with amidine-like functional group modifications would inhibit matrix metalloproteinase (MMP) activity, a precursor to myofibroblast formation. MMP Inhibition would impede cleavage of latent transforming growth factor beta (L-TGF-β) to transforming growth factor beta (TGF-β), a cytokine that stimulates fibroblast to myofibroblast differentiation. Cell staining was performed on NIH 3T3 fibroblasts cultured on each biomaterial and stimulated by L-TGF-β and TGF-β to evaluate material performance. Fibroblast viability was found to be >70% on each material. These biomaterials have potential for use as a coating of microencapsulated islet cells for diabetes therapy. This study is also important for furthering understanding of the biology involved in fibrous capsule formation.</p

Nucleotide and nucleotide sugar analysis in cell extracts by capillary electrophoresis

In biotechnological processes the intracellular level of nucleotides and nucleotide sugars have a direct impact on the post-translational modification (glycosylation) of the therapeutic protein products and on the exopolysaccharide pattern of the cells. Thus, they are precursors and also key components in the production of glycoproteins and glycolipids. All four nucleotides (at different phosphorylation stages) and their natural sugar derivatives coexist in biological samples. Their relative ratios depend on the actual conditions under which the cells are grown. Therefore, their simultaneous determination at different time points and different cell culture conditions in biotechnological samples is of interest in order to develop the optimal cell culture process. In our study capillary electrophoresis (CE) combined with UV detection @ 260 nm was selected for the separation and quantification of the complex nucleotide mixture of the structurally very similar nucleotides and nucleotide sugars in cell extracts. The high separation efficiency of CE as well as its insensitivity to the complex cell matrix makes this method superior to commonly used HPLC methods. In our study eleven nucleotides and six nucleotide sugars were analyzed. A robust and reproducible analysis system was developed. As background electrolyte borate (40 mM, pH 9.5) was used containing 1% PEG (MW 35'000 Da) which enhanced resolution. In order to obtain high reproducibility in terms of migration time, mandatory for the unambiguous identification of the single compounds in the complex cell extract mixtures, dynamic coating was also employed. The method was tested for CHO cell extracts where three sugar nucleotides and seven nucleotides were identified and quantified using GDP-Glc as internal standard

Nucleotide and Nucleotide Sugar Analysis in Cell Extracts by Capillary Electrophoresis: FH-HES Universities of Applied Sciences

In biotechnological processes the intracellular level of nucleotides and nucleotide sugars have a direct impact on the post-translational modification (glycosylation) of the therapeutic protein products and on the exopolysaccharide pattern of the cells. Thus, they are precursors and also key components in the production of glycoproteins and glycolipids. All four nucleotides (at different phosphorylation stages) and their natural sugar derivatives coexist in biological samples. Their relative ratios depend on the actual conditions under which the cells are grown. Therefore, their simultaneous determination at different time points and different cell culture conditions in biotechnological samples is of interest in order to develop the optimal cell culture process. In our study capillary electrophoresis (CE) combined with UV detection @ 260 nm was selected for the separation and quantification of the complex nucleotide mixture of the structurally very similar nucleotides and nucleotide sugars in cell extracts. The high separation efficiency of CE as well as its insensitivity to the complex cell matrix makes this method superior to commonly used HPLC methods. In our study eleven nucleotides and six nucleotide sugars were analyzed. A robust and reproducible analysis system was developed. As background electrolyte borate (40 mM, pH 9.5) was used containing 1% PEG (MW 35'000 Da) which enhanced resolution. In order to obtain high reproducibility in terms of migration time, mandatory for the unambiguous identification of the single compounds in the complex cell extract mixtures, dynamic coating was also employed. The method was tested for CHO cell extracts where three sugar nucleotides and seven nucleotides were identified and quantified using GDP-Glc as internal standard

Évaluation des pratiques professionnelles en matière de gestion du risque infectieux au cabinet d’ophtalmologie en région Bourgogne

Doi : JFO-09-2007-30-7-0181-5512-101019-200700138National audienceObjectives: To evaluate the hygiene practices during ophthalmologists’consultations in Burgundy, France, so as to identify the difficulties they encounter in implementing new professional guidelines. Method: The survey was based on an anonymous transversal descriptive survey conducted via a questionnaire sent in May 2006 to 102 ophthalmologists. Results: Data from 51 questionnaires were included in the survey, showing a good response rate (50%). The survey revealed that the perception of the risk of transmitting an infection was “important” to “most important” (59.2%). A steam autoclave was used by 38.8% of the ophthalmologists. Those who did not sterilize instruments disinfected them (30%). Finally, ophthalmologists preferred more information to training (90% versus 50%, p=0.015). Conclusion: This survey highlights the need for improvements in education for practitioners and their assistants, especially in the sterilization of instruments and equipment.Objectif : Évaluer les pratiques des ophtalmologistes bourguignons en consultation, afin d’identifier les difficultés rencontrées notamment dans la mise en place des nouvelles recommandations professionnelles en matière de gestion du risque infectieux. Méthode : L’évaluation des pratiques a reposé sur une enquête descriptive transversale anonyme ; 102 ophtalmologistes ont reçu un auto-questionnaire par voie postale, entre avril et mai 2006. Résultats : Cinquante et un questionnaires ont été exploités, soit un taux de participation des ophtalmologistes de 50 %. Le risque de transmission d’une infection en général a été perçu comme important à très important dans 59,2 % des cas. Un autoclave à vapeur d’eau est présent chez 38,8 % des ophtalmologistes. Pour ceux qui ne possèdent pas d’autoclave à vapeur d’eau, 30 % font stériliser leurs instruments par un établissement de santé et 70 % réalisent une désinfection. Enfin, une demande d’information plus que de formation a été souhaitée par les praticiens (90 % versus 50 % ; p = 0,015). Conclusion : Les différents constats faits lors de cette enquête ont permis d’envisager des actions d’amélioration possibles en matière de formation initiale et continue des praticiens et de leurs assistants, notamment concernant la décontamination du matériel

Preparation of cellulose II and IIII films by allomorphic conversion of bacterial cellulose I pellicles

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Grape seed extracts inhibit dentin matrix degradation by MMP-3

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EMMPRIN/CD147 deficiency disturbs ameloblast-odontoblast cross-talk and delays enamel mineralization

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