|Articles about Biomaterials|
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| [Repairing segmental radial bone defect with poly (3-hydroxybutyrate-co-3-hydroxyvalerate)/sol-gel bioactive glass composite porous scaffold]
Yu, S. J., G. X. Qiu, et al. (2005), Zhongguo Yi Xue Ke Xue Yuan Xue Bao 27(2): 185-9.
Abstract: OBJECTIVE: To investigate the capability of the bone regeneration of poly (3-hydroxybutyrate-co-3-hydroxyvalerate/sol-gel bioactive glass (PHBV/SGBG) composite porous scaffold. METHODS: PHBV/ SGBG composite porous scaffold was implanted into the segmental radial bone defect of the New Zealand white rabbits, PHBV/hydroxylapatite (PHBV/HA) as experimental control. The degradability, biocompatibility, and bone regeneration capability of the implants were evaluated through radiological, histological, computerized graphic, and biomechanical analysis. RESULTS: The new bone formation occurred as early as 4 weeks after implantation of PHBV/SGBG composite porous scaffold. The defect was filled with new bone 8 weeks after the implantation, and was completely repaired 12 weeks after operation. The new bone had normal bone structure and the medullar cavity regenerated. The biomechanical study showed that the anti-compression force of radial specimen in PHBV/SGBG groups was significantly higher than in PHBV/ HA groups (P < 0.05), but no significant difference existed between PHBV/SGBG group and autograft bone group (P>0.05). The PHBV/SGBG composite porous scaffold degraded no sooner than 4 weeks after the implantation and most of scaffold was absorbed after 12 weeks. The proportion of the scaffold to new bone decreased from 60% by week 4 to 8% by week 12. CONCLUSIONS: PHBV/SGBG composite porous scaffold is a degradable bone substitute. It can achieve early bone generation and complete repair. It can be used as an ideal scaffold for tissue-engineering bone.
| [Researches on surface modification for prevention of bacterial adhesion to implanting biomaterials]
Wu, G., C. Wan, et al. (2000), Sheng Wu Yi Xue Gong Cheng Xue Za Zhi 17(1): 84-6.
Abstract: The failure of operation caused by biomaterials centered infections (BCI) has seriously restricted the clinical application of biomaterials. Two mechanisms of bacterial adhesion and the relationship between surface free energy of bimaterials and bacterial adhesion are introduced and discussed in this paper. Increasing the surface free energy can improve (decrease) the adhesion of some kinds of bacteria. At last, some methods of the surface modification are reviewed.
| [Restoration of the alveolar crest with a biomaterial filler. A clinical and histological study]
Chomette, G., M. Auriol, et al. (1988), Rev Stomatol Chir Maxillofac 89(5): 276-80.
Abstract: The implantation of biocompatible hydroxyapatite is used for human mandibular ridge augmentation in edentulous patients. Histologically, we studied such a material after a long period of implantation (1 1/2 to 2 years) in two patients. The histologic study showed a narrow meshed net of collagen tissue surrounding the hydroxylapatite particles. In the periphery of that tissue, we could see an osteogenesis: the bony trabeculae thus formed firstly were made of an immature bony matrix with an irregular "woven" pattern; secondarily, a mature bone, quite similar to the normal bone, occurred. In our two observations, there was an unusual inflammatory reaction characterized by cellular infiltration of lipophages, lymphocytes and plasma cells in the connective tissue and in one case by a true ischaemic necrosis with granuloma and bacteria. In spite of that inflammation, the whole material was well tolerated, without foreign-body granuloma. Such a granuloma was only found in superficial areas of the gingiva, around extruded particles of the biomaterial.
| [Results of treatment of chronic generalized periodontitis with a dispersed biomaterial Alloplant]
Bulgakova, A. I., M. Z. Mirgazizov, et al. (2004), Stomatologiia (Mosk) 83(1): 19-22.
Abstract: There is a method of treatment of generalized chronic periodontitis with using dispersing biomaterial Alloplant and immunological, histomorphological criteria of this estimation.
| [RGD peptides and endothelialization of biomaterials]
Wu, Z., Y. Shi, et al. (2001), Sheng Wu Yi Xue Gong Cheng Xue Za Zhi 18(2): 269-71, 275.
Abstract: Endothelialization can remarkably improve blood compatibility of biomaterials and promote their clinical application, especially the uses of cardiovascular grafts. The attachment and growth of endothelial cells on artificial surfaces is the critical factor affecting the process of endothelialization. Many adhesive proteins contain the Arg-Gly-Asp(RGD) sequence which plays an important role in cell adhesion, migration and growth. In this review, the interaction of RGD peptides sequence and integrins, the influential factors of RGD peptides bioactivity and its application in endothelialization of biomaterials were discussed.
| [Roentgen contrasting of resorbable biomaterials PHB and PLA]
Michalik, I., J. Winkler, et al. (1998), Biomed Tech (Berl) 43 Suppl: 426-7.
| [Scanning electron microscopy (SEM) and microanalysis (EDS) applied to the study of biomaterials for dental use. 6]
Valdre, G., R. Mongiorgi, et al. (1995), Minerva Stomatol 44(1-2): 55-68.
Abstract: The study considers the use of scanning electron microscopy (SEM) and EDS microanalysis applied to the study of numerous mineral-based biomaterials of common use in odontostomatology. The products studied are the following: reabsorbable Dac Blu, non reabsorbable Dac Blu, non reabsorbable atomized Dac Blu, non rabsorbable fine Dac Blu, reabsorbable Biocoral 450, Calcitite 2040-12, Orthogel, Apagen, BTF 65, Calcitite 4060-2, Osprogel, Bio-Oss, Biostite, Ospro-vit, Merck Hydroxyapatite. By means of SEM it was possible to study the morphology and the microchemistry of the various biomaterials so as to have information about their physical and chemical characteristics, such as the crystalline form, the crystalline aggregations, the space dimensional distribution of the pores and check the possibilities of composition variability. All of these factors are fundamental to evaluate the functional biocompatibility of a biomaterial, once that its performance in a biological environment is known.
| [Scanning probe microscopy as a test procedure for coated hydrophilic silicone biomaterials]
Bischoff, R., A. Berghaus, et al. (1997), Biomed Tech (Berl) 42 Suppl: 482-3.
| [Secondary cataract and IOL type and the shape of its optic part]
Iashinskas, V. P., R. Zhemaitene, et al. (2005), Vestn Oftalmol 121(1): 13-6.
Abstract: Although cortical remains are purged from the capsule sac by special techniques and better IOL models are used for implantation, opacification of the posterior capsule (OPC) persists to be one of the most frequent complications in modern cataract surgery. The frequency rate of OPC depends on used evaluation criteria. A total of 165 eyes were examined after cataract extraction for OPC. Four types of IOL were used; they are hydrophobic acryl three-part IOL (AcrySof MAZOVA, n = 46), hydrophobic acryl all-in-one IOL (ArySofSA30AL, n = 38) and silicone three-part (CeeOn911A, Pharmacia, n = 42). OPC were evaluated by EPCO 2000 computer soft. When IOL with the straight edge of the optic axis were in use (both silicone and acryl ones), there was registered, in 1 year after surgery (p < or = 0.05) a reliably lower frequency and intensity of OPC versus IOL with the curved edge of the optic axis. The shaped curvature in the posterior capsule encompassing tightly the IOL edge prevented further migration of lens cells. The IOL material (hydrophobic acryl or silicone) is of no importance for the OPC development. There was no reduction in visual acuity and no laser capsulotomy was made in any of the groups of patients.
| [Secondary reconstruction of anophthalmic orbits by intraorbital biomaterial implantation]
Adenis, J. P., P. Bertin, et al. (1999), J Fr Ophtalmol 22(2): 269-73.
Abstract: Poor cosmetic symptoms related to enucleation or evisceration, lead to the post enucleation socket syndrome. A surgical technique is described, with implantation of hydroxyapatite tricalcium phosphate ceramic blocks in the intraorbital fat.
| [Significance and technique of autologous chondrocyte transplantation]
Fritz, J., C. Gaissmaier, et al. (2005), Zentralbl Chir 130(4): 327-32.
Abstract: The bad risk for an early onset of osteoarthritis in the knee increases with the size of a cartilage defect. A collateral meniscus- or ligament-tear will enforce this hazard in addition. In order to avoid such a development, relevant full-thickness cartilage defects should be reconstructed biologically and attendant meniscus- or ligament-tears as well as varus- or valgus deformities should be treated. A number of studies, including some prospective-randomized trials, have shown that autologous chondrocyte transplantation (ACT) is the most reliable procedure for a surgical treatment of full-thickness cartilage defects larger than 4 cm (2) in adults. One disadvantage of ACT is the extensive approach to the joint and often a hypertrophy of the repair tissue. To solve these problems, some different biomaterials for a matrix-assisted ACT have been developed. The scaffold we use has a covering membrane upside and a collagen-sponge carrying the chondrocytes. By means of special surgical instruments a minimally invasive implantation is possible, reducing the side-effects of an extensive approach. Animal studies showed the regeneration of a hyaline cartilage using our described system. However, results of current clinical studies with the different scaffolds must be awaited before an universal application of matrix-assisted ACT can be recommended.
| [Significance of crown-down root canal preparation technique in endodontic therapy by using the hydroxylapatite sealer]
Teodorovic, N. and Z. Martinovic (2005), Vojnosanit Pregl 62(6): 447-52.
Abstract: AIM: To evaluate the crown-down preparation technique, and the use of hydroxylapatite based material for the definitive root canal obturation. METHODS: The investigation included 20 single-canal roots with chronic periapical inflammatory lesion. Biomechanical medicamentous canal preparation was done using the double-flared technique with balanced force, and the obturation was performed with hydroxylapatite sealer (unicone technique). Clinical and radiographic check-up performed 12 months after the treatment, used the following parameters: pain, swelling, percussion and palpation sensitivity, and the presence of fistula. RESULTS: The obtained results showed a successful treatment in 18 cases, while in the 2 cases the treatment failed. CONCLUSION: These findings suggested that the crown-down preparation technique efficiently cleaned and shaped the root canal, and that the hydroxylapatite-based material created the homogenous and hermetic root canal obturation, so this methodology could be recommended for the endodontic therapy.
| [Significance of synovial fluid analysis in the diagnosis of rheumatoid arthritis]
Ishiguro, N. (2005), Nippon Rinsho 63 Suppl 1: 362-6.
| [Silk protein fiber biomaterials and tissue engineering]
Huang, J. K. and M. Li (2004), Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi 18(2): 127-30.
Abstract: OBJECTIVE: To summarize the latest developments in silk protein fiber as biomaterials and their applications in tissue engineering. METHODS: Recent original literature on silk protein fiber as biomaterials were reviewed, illustrating the properties of silk protein fiber biomaterials. RESULTS: The silk protein fiber has the same functions of supporting the cell adhesion, differentiation and growth as native collagen, and is renewed as novel biomaterials with good biocompatibility, unique mechanical properties and is degradable over a longer time. CONCLUSION: Silk protein fiber can be used as a suitable matrix for three dimensional cell culture in tissue engineering. It has a great potential applications in other fields.
| [Sodium fluoride controlled release system for intra buccal use]
Diarra, M., G. Pourroy, et al. (2004), Dakar Med 49(1): 44-50.
Abstract: Hydroxyapatite which has the same elemental chemical composition as natural bone and teeth is one of the promising raw material for the design of drug controlled release system in intrabuccal use. It is stable and biocompatible and widely used in orthopedics and odontology. So, in order to improve the administration of drugs for intrabuccal use, we have developped a fluoride controlled release delivering system. We have formulated tablets of 160 to 200 mg to be fixed on the vestibular face of a molar or a premolar and permitting to reach high enough local concentrations for desirable therapeutic effect. The tablets have a granular matrix composed of hydroxyapatite and fillers, ethylcellulose and/or Eudragit. For all tablets, the pharmacotechnical values support the pharmacopoeia norms. On fragments of tissue maintained in culture, the sodium fluoride is released at constant rate. The release profiles observed are predictable. No disintegration of tablets have been observed during release studies and after. Histological analyses performed after release studies showed the biocompatibility qualities of the tablets.
| [Sonication of biomaterial and the regulation of acoustic parameters]
Wang, B., J. Wang, et al. (2004), Sheng Wu Yi Xue Gong Cheng Xue Za Zhi 21(4): 662-5.
Abstract: The acoustic properties of ultrasound and the interaction of biomaterial and cavitation are analyzed. The relation between ultrasonic parameters and sonication is indicated. Our research revealed that different sonication aims must well match with different acoustic properties for optimizing the sonication technology. Based on the theory of wave superposition, a method for enhancement of ultrasonic intensity in wide dimension is introduced. A large scale powerful polyhedral acoustic field is built according to the research above. The rationality and effectiveness of the method are demonstrated through examination.
| [Spinal cord regeneration in rats after thoracic segmentectomy: restoration of the anatomical integrity of the spinal cord]
Iarygin, V. N., V. V. Banin, et al. (2005), Morfologiia 127(2): 39-43.
Abstract: Spinal cord (SC) segmentectomy was performed at ThX level in 28 rats. The scar formation in place of surgery and the degree of restoration of anatomical integrity were studied in control rats (group I) and in rats, in which SC defect was replaced by either Spherogel neuromatrix (group II) or Spherogel containing dispersed embryonic nerve cells (group II). While in group I rats by weeks 1-2 SC defect was filled with fibrin masses, in rats of experimental groups II and III the formation of connective tissue scar was found by the same time. By weeks 10-11 these animals demonstrated partial restoration of motion in three joints of the hindlimb. In the scar tissue and in adjacent SC zones numerous regenerating thin myelinated nerve fibers were found. They were clearly demonstrated in the zones of cranial and caudal borders along the whole distance until the appearance of typical tissue of SC. In slides from the animals of control group, thin myelinated nerve fibers were found only in close proximity to SC substance, while in the scar tissue and in the cellular bands of the intermediate zone nerve fibers were scarce.
| [Stability of grafts and implants after bone grafting of the maxillary sinus. Retrospective analysis of 44 patients]
Baccar, M. N., B. Laure, et al. (2005), Rev Stomatol Chir Maxillofac 106(3): 153-6.
Abstract: OBJECTIVES: We assessed the reliability of maxillary bone grafting and implant stability, comparing our results with reports in the literature. MATERIAL AND METHODS: This retrospective series included 44 patients who underwent maxillary sinus bone grafting between 1998 and 2002. An analogous graft was used for 31 patients and a combination autologous-bone substitute graft for 13. One hundred twelve dental implants were positioned at the grafting site (2.5 implants per graft). We assessed recipient site morbidity, bone graft integration and stability, and stability of the implants. RESULTS: Bone grafting was successful in 97.8% of patients. There was one failure. Two of the 112 implants failed. DISCUSSION: Our results are comparable with those in the literature. This study demonstrated the reliability of maxillary bone grafting with equivalent results using autologous bone and combination autologous bone-bone substitute.
| [Standards and new developments in the chemotherapy of glioblastomas]
Weller, M. (2005), Dtsch Med Wochenschr 130(40): 2270-4.
Abstract: For 25 years involved-field radiotherapy has remained the mainstay of postoperative treatment for glioblastoma. In contrast, the role of adjuvant chemotherapy in addition to radiotherapy has remained controversial. A recent randomized multinational phase III trial (EORTC 26 981/22 981/NCIC CE.3) assessing concomitant and adjuvant chemotherapy with the alkylating agent, temozolomide, in addition to radiotherapy in newly diagnosed glioblastoma defines an increase in median survival from 12.1 months with radiotherapy alone to 14.6 months with radiochemotherapy and an increase in the 2-year survival rate from 10 to 26 %. Subgroup analysis revealed that the gain in survival in the experimental arm was largely achieved in patients with glioblastomas which exhibited a methylation of the promoter region of the O (6)-methylguanine DNA methyltransferase (MGMT) gene and thus did not express MGMT. MGMT is a DNA repair enzyme which repairs DNA lesions induced by chemotherapy with alkylating agents. The cellular MGMT stores are consumed during DNA repair, suggesting that temozolomide itself may deplete MGMT and thus overcome its own most important pathway of resistance. EORTC 26 981/22 981/NCIC CE.3 thus defines a milestone in the treatment of glioblastoma and will provide a platform for further efforts at improving the outcome for patients suffering from this still invariably fatal neoplasm.
| [Staphylococcus epidermidis biofilms on intraocular lens surface: review of the literature]
Kodjikian, L., C. Roques, et al. (2005), J Fr Ophtalmol 28(2): 224-30.
Abstract: Bacterial adhesion to intraocular lenses (IOLs) takes place during their implantation. This is a prominent etiological factor of postoperative endophthalmitis. Following adhesion, secretion of an extracellular matrix (called slime for Staphylococcus epidermidis) and formation of multiple layers of microcolonies lead to the colonization of the biomaterial surface. Scanning electron microscopy photographs illustrate the different steps of biofilm formation. The different adhesins expressed by S. epidermidis involved in the adhesion process are described. The biofilm is not only an adhesive medium; it also affects virulence. Last, notions on biofilm physiology are discussed in an attempt to explain the dynamic equilibrium of this system. In 2004, the perfect biomaterial able to prevent postoperative endophthalmitis does not yet exist. Moreover, there is no effective tool, at the present time, to fight against mature biofilms. Therefore, preventing biofilm formation remains capital, which requires perfect knowledge of all stages of formation and the factors involved.
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