Biomaterials.info - Resources for Engineers

Record 81 to 100

[Biomaterials used in tissue engineering for cartilage regeneration]
Ma, Z., C. Gao, et al. (2001), Sheng Wu Yi Xue Gong Cheng Xue Za Zhi 18(4): 638-41, 652.
Abstract: In this paper are reviewed the research reports on biomaterials used in recent years in the field of tissue engineering for cartilage regeneration. The preparation of these biomaterials are also discussed. Finally, ideas are proposed to solve the problems in the field of cartilage tissue engineering.

[Biomaterials vectors of growth factors]
Dard, M. and N. Passuti (2000), Rev Chir Orthop Reparatrice Appar Mot 86 Suppl 1: 154-6.

[Biomaterials, human tolerance and integration]
Wintermantel, E., J. Mayer, et al. (1999), Chirurg 70(8): 847-57.
Abstract: Biomaterials and related process engineering in order to obtain optimal surface and structural biocompatibility of implants and devices are presented. Vital-avital composites for tissue engineering, cell culture models, porous ceramics and degradable polymers are introduced as examples. Emphasis is laid on the conversion of basic research results into clinical applications and on the exchange of technologies from the non-medical into the medical field and vice versa.

[Biomaterials: joint prosthesis materials]
Tanji, H., SasakiT, et al. (1985), Iyodenshi To Seitai Kogaku 23(6): 380-4.

[Biomaterials]
Masuhara, E. and Y. Kadoma (1982), Iyodenshi To Seitai Kogaku 20(7): 593-4.

[Biomaterials]
Peronneau, P. and M. Nakache (1981), C R Seances Soc Biol Fil 175(5): 598-635.
Abstract: Biomaterials--materials used for the elaboration of systems designed for human implantation or organ substitutes--can be classified as metals and alloys, ceramics and polymers. Their uses are largely diversified, for soft and hard tissues replacement. Interactions rise between biological environment and implants, the mechanisms of them not always known: inflammatory response, corrosion and degradation of materials leading to leaching of some constituents possibly toxic and alteration of their mechanical properties. Blood interfacing materials introduce some particular problems of hemocompatibility. The matching of implant to biological medium, in other words, its biocompatibility has to be a priori evaluated, but until now no in vitro or in vivo evaluation method is fully reliable.

[Biomaterials]
Schacht, E. (2004), Verh K Acad Geneeskd Belg 66(4): 242-5.
Abstract: Biomaterials are essential components in the development of artificial organs. Synthetic polymers are widely used for a number of biomedical applications: a) as medical supplies, b) devices to support or replace malfunctioning body parts or c) systems with a local therapeutic function. The design of biomaterials has developped over the past three decades from devices with a mechanical function, over systems with a dedicated function (degradable, drug releasing, surface modified) to devices which are tailor made to interact in a smart way with the biological environment. At present polymers are attractive materials to construct scaffolds for tissue regeneration and regenerative medicine. The material design is adapted to the requirements for cell ingrowth, cell migration, angiogenesis etc. This is mainly controlled by the surface topography and chemistry that play a key role in the interfacial material-cell communication. This remarkable development is the direct result of a multi-disciplinary approach, combining material science with engineering, cell biology, molecular biology, medicine and regulatory guidelines.

[Biomechanics and biomaterials--dental instruments, prosthesis and bone regeneration]
Hiroo, M. (2003), Kokubyo Gakkai Zasshi 70(3): 153-61.

[Biomemetic surface modification of biomaterials related to tissue engineering]
Yao, K., F. Shen, et al. (2000), Zhonghua Zheng Xing Wai Ke Za Zhi 16(6): 331-2.

[Bioresorbable bone adhesives. Historical perspective and current status]
Heiss, C. and R. Schnettler (2005), Unfallchirurg 108(5): 348-55.
Abstract: Bone adhesives are degraded to non-toxic products and resorbed after fulfilling their function in contact with living tissue. There has been a growing interest in the use of such adhesives in all fields of medicine in recent years. The wish of trauma surgeons and orthopaedic for alternatives to osteosynthesis is reflected in the development of a variety of surrogates of biological or synthetic origin. Despite a longstanding history of research in this field, a clinically applicable alternative in the field of bone gluing has not yet been found. This application has consistently failed because these adhesives were not tailored to the conditions met within the living organism. The following article is meant to provide an overview of the development, the state of the art, and today's knowledge of bone adhesives. In addition, it points out the tremendous progress in this area, made possible by the joint efforts of basic researchers and surgeons. The results of this collaboration show that in the future a successful reconstructive surgery using synthetic biomaterials will become feasible.

[Bladder stone at an ureterovesical anastomotic site after renal transplantation: a report of three cases]
Watanabe, Y., S. Itoh, et al. (2005), Hinyokika Kiyo 51(2): 97-100.
Abstract: Three cases of bladder stones at the ureterovesical anastomotic site after renal transplantation (RT) are reported. The three patients were successfully treated with kidney grafts. The method used for the ureter bladder anastomosis in all patients was the extravesical technique with polyglyconate (Maxon) for case 1 and a polydioxanone suture (PDSII) for cases 2 and 3. Calculi formation was found between 3 to 15 months after RT. Endoscopic vesicolithotripsy was performed and the stones adherent to the ureterovesical anastomotic site were removed successfully in all cases. Stone analysis revealed uric acid (case 1), CaOx and CaP (case 2). Stone analysis was not done in case 3. The patients' symptoms improved and no bladder stones could be discerned postoperatively.

[Bone biomaterial]
Poitout, D. G. (1995), Bull Acad Natl Med 179(3): 517-31; discussion 531-6.
Abstract: The use of deep frozen allografts is not a recent technic. The evolution of the conservative technics authorize a sufficient preservation of osseous and cartilaginous structure. The clinical results are considered as good in most of the cases. The intra medullary cells are most involved in immunological responses but clinically speaking only 10% to 20% of the case treated has a reject. The becoming of the grafted tissue is best if the recipient is young, the graft well fixed and the muscular surrounding well vascularized. 454 grafts and 64 massive osteochondral allografts have been archived between 1979 and 1993 for traumatic, tumoral, and surgical diseases. The results have been considered as good or excellent in 85% of the cases. The actual problems are the biomechanical behaviour of the ligamentary revascularization and fixation which gives in numerous cases a high percentage of loosening.

[Bone harvesting from the iliac crest]
Jager, M., B. Westhoff, et al. (2005), Orthopade 34(10): 976-82, 984, 986-90, 992-4.
Abstract: BACKGROUND: Autogenous bone grafts from the iliac crest are frequently harvested for autologous bone transplantation. Although an autologous bone transplant does improve the local bone healing potency, significant donor site morbidity must be considered. METHODS: In this study we elucidate special bone harvesting techniques from the iliac crest and review the literature related to clinical significance of donor site morbidity. Furthermore, our own experiences are compared and discussed critically with relevant data of other investigators. RESULTS: The increasing number of scientific publications which focus on bone harvesting techniques and related complications in recent years indicate the high interest and relevance of this issue. There is a tendency to alternatives such as biomaterials as bone substitutes, whereas the role of growth factors and cell therapeutics in the treatment of bony defects are still being evaluated in clinical studies. CONCLUSION: Although autologous, heterotopic bone transplantation is still the gold standard in the treatment of bony defects, there is a tendency towards the application of biomaterials, stem cells, and growth factors. Conscientious observation of relevant anatomic considerations during bone harvesting procedures may help to avoid complications.

[Bone integration and apposition of porous and non porous metallic orthopaedic biomaterials]
Likibi, F., M. Assad, et al. (2005), Ann Chir 130(4): 235-41.
Abstract: The objective of this study was to evaluate the functionality of two intervertebral fusion implants, a porous nickel-titanium and a conventional titanium cage system in a sheep model. Eighteen sheep each received the two-implant devices at L2-L3 and L4-L5 lumbar levels. The sheep were sacrificed at three different postsurgical periods: three, six and 12 months. Lumbar segments were harvested. Qualitative (macroscopic and microscopic) and quantitative (histomorphometric) histological analysis were carried out on histological slides. The results indicated that a porous nickel-titanium had obtained a better osseointegration than the titanium implant. The functionality of two implants seemed to be influenced by the implant structure and shape. However, biocompatibility of two implants seemed comparable.

[Bone resection-reconstruction of the diaphyseal zone in animals. Development of an experimental model, application to the study of biomaterials compared with allografts]
Gouin, F., N. Passuti, et al. (1994), Chirurgie 120(2): 80-3.
Abstract: The aim of this work was to develop an animal model of bony resection-reconstruction of the diaphyseal zone and to test the different bone substitutes in comparison with allografts. Eighteen 2-cm diaphyseal resections of the femur were performed in Beagle dogs. Reconstruction was performed using a bone substitute (5 cryopreserved allografts, 5 blocks of polymethylmetracylate with PMH hydroxyapatite, 8 blocks of phosphocalcium ceramic materials with biphased macropores) associated with centromedullar lockek nail. The PMH blocks gave radiographically and histologically unsatisfactory results. Allografts consolidated in two-thirds of the junctions, consolidating with an exuberant periosteal callus contrasting with minimal intracortical repair. No stress fractures were observed despite normal activity. BCP blocks consolidated in three-fourths of the junctions but pseudoarthrosis at the centre of the block was observed in cases in which the fixation was not perfectly stable. Bone occupied 20 and 24% of the surface of the ceramic block in the central and junctional zones respectively. These findings demonstrated the reliability of internal fixation material in the animal model and allowed us to evaluate the different methods for analysing bone repair on histographic and microradiographic images. In addition, the potential of synthetic material such as MBC might be useful in large resections in mechanically stressed zones.

[Bursting pressure in normal and ischemic colonic anastomoses in rats; using biological and synthetic adhesives]
Farias-Llamas, O. A., A. Orozco-Mosqueda, et al. (2005), Cir Cir 73(1): 31-42.
Abstract: OBJECTIVE: We wanted to determine bursting pressure in normal and ischemic colonic anastomoses in rats as well as the frequency and type of complications with the use of biological and synthetic adhesives. MATERIAL AND METHODS: We designed an experimental study using 80 Sprague-Dawley rats, weighing between 200 and 250 g, divided into four groups: one control group and three study groups. Anastomoses were realized using one layer of interrupted 6-0 polypropylene sutures. Each group was divided into two categories: normal colon (n = 10) and ischemic colon, induced by dividing mesenteric blood vessels (n = 10). Group 2 used octyl-cyanoacrylate, group 3 used N-2-butyl-cyanoacrylate, and group 4 used 40 mg/ml fibrinogen with 1000 u/ml of thrombin. Bursting pressure was measured with a manometer creating pressure in the anastomotic bowel using an infusion pump at 1 ml/min of NaCl 0.9%. Statistical analysis was performed with Student's t test, one-way ANOVA, chi square test or Fisher's exact test. RESULTS: Group 1: (control) normal 127.8 +/- 16.21 versus 109 +/- 17 with ischemia (p < 0.05); group 2: normal 145.5 +/- 89 versus ischemic colon 97.6 +/- 40 (p = 0.136); group 3: normal 145.7 +/- 34 versus 130.8 +/- 15.33 with ischemia (p = 0.22); group 4: normal 239 +/- 26.4 versus 196.5 +/- 14.3 with ischemia (0.000). Bursting pressure was statistically significant in group 4, showing greater pressures (p < 0.001). Bursting segment was shown to be higher outside the anastomoses. Complications such as adhesions and intestinal obstruction were seen more frequently in both cyanoacrylate groups. CONCLUSIONS: An increased bursting pressure was shown in the fibrinogen groups, having a greater tensile strength of the anastomoses. Pressures similar when anastomoses were treated with any of the other two synthetic adhesives.

[Calcium-oxygen modified amorphous and nanocrystalline carbon layers as biomaterials]
Dorner-Reisel, A., C. Schurer, et al. (2002), Biomed Tech (Berl) 47 Suppl 1 Pt 1: 393-6.
Abstract: Undoped and Ca-O-modified diamond-like carbon coatings were deposited by a direct current discharge. Hardness and Young's modulus of Ca-O-modified DLCs were reduced in comparison with the undoped DLC, but the adherence of the Ca-O-modified films is improved. Ca-O-modified DLCs have a higher fraction of nano-crystalline regions with carbon in sp2 hybridisation. In addition, an increased oxygen content and CaCO3 was identified in Ca-O-modified DLCs. While mouse fibroblasts of the type L929 attach and grow on unmodified diamond-like carbon coatings synthesized by the decomposition of hydrocarbon, the addition of CaO-H2O into the precursor gas improves the coatings biological acceptance by the cells.

[Can samples from the cups of Weller endoprosthesis be the basis for analysis of the degree of biomaterial crystallinity under the influence of external factors?]
Duda, P., J. Cybo, et al. (2001), Chir Narzadow Ruchu Ortop Pol 66(5): 443-7.
Abstract: The paper is a thesis verification. The thesis stated that samples from cups of Weller endoprosthesis can be the basis of biomaterial crystallinity analysis under the influence of external factors. Cup segments were deformed and exposed to X-rays. Basing on thermoanalytic analysis the authors prove that the cups (completely transformed and sterilized) cannot be used as research material, to be tested by application of external factors, to assess polyurethane morphology. An alternative reliable method has been proposed: direct investigation of the material used for cup production. These conclusions were reached as result of research done with a differential scanning calorimeter (heat-flux type) DCS 30 in Mettler TA-4000 thermoanalytic system.

[Carbon fiber composite biomaterials in the substitution of the inferior vena cava]
Ratto, G. B., R. Di Primio, et al. (1989), Ann Chir 43(4): 311-4.
Abstract: A new type of vascular prosthesis made of pyrolytic carbon fibres, was tested on growing pigs. Fourteen graft (8 x 30 mm) were implanted as inferior vena cava (IVC) substitutes. The blood conduits were removed 15 s, 60 min and 7, 15, 30, 60 and 120 days after implantation. Specimens were examined by light and scanning electron microscopy. Ten similar pigs underwent excision and re-implantation of 30 mm segment of IVC, and where used as controls. Carbon fibres grafts removed within 7 days after implantation were patent: at the subsequent observation times, the prosthetic segments appeared completely or partially thrombosed. Four of the 10 venous autografts failed. Shortly after implantation, a thick neointimal layer covered the inner surface of carbon grafts. This phenomenon delayed organization and neo-endothelialization of the neointima, exposing carbon segments to blood deposits.

[Cardiovascular biomaterials]
Loisance, D. (1995), Bull Acad Natl Med 179(3): 537-46; discussion 547.
Abstract: Hemocompatible biomaterials, i.e. materials to be used in a biological environment, are of various origins (biological, synthetic). The great variety of physical and chemical characteristics has allowed design of various prosthesis and artificial organs. Use of biomaterials and artificial organs has made possible the development of substitutive therapies, a growing component of medical care. None of the biomaterials presently used is ideal. Everyone of them is responsible for a local and general reaction: foreign body reaction, coagulation, whole body inflammatory response. For years, these reactions have been poorly understood and development was of a very empirical nature. Progress in cellular and molecular biology permits today a better understanding of the mechanisms involved in these reactions. Use of biomaterials is facing to day a difficult problem; liability concerns threaten further developments and leads to market withdrawal of major basic materials.

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