Biomaterials.info - Resources for Engineers

Record 181 to 200

[Immediate filling of extraction sites in general practice: use of a resorbable biomaterial, natural coral]
Ouhayoun, J. P. and D. Etienne (1989), Inf Dent 71(4): 225-38.

[Immobilization of von Willebrand factor antibody on solid host membranes]
Gao, Y. and X. Yang (2005), Sheng Wu Yi Xue Gong Cheng Xue Za Zhi 22(5): 971-4.
Abstract: This study aimed at immobilizing the antibodies on the surfaces of the solid host membranes in order to improve the property of the biomaterial. The von Willebrand factor (vWf) antibodies were immobilized on the surface of Bombyx mori silk fibroin and PLA (Poly Lactic Acid) membrane by NH3 plasma treatment followed by covalent cross-linking reaction. The immobilization efficiency was evaluated by two methods including the antibody surplus and enzyme-linked immunosorbent assay (ELISA). The in vitro antithrombogenicity representing the activity of immobilized vWf antibody was determined by the method of Activated Partial Thromboplastin Time (APTT), Prothrombin Time (PT) and Thrombin Time (TT) test. The results demonstrate that the vWf antibodies are immobilized on silk fibroin and PLA membranes in an efficient way with the efficiency of antibody surplus up to 23.88% and ELISA reaction is positive. APTT and TT exceeded the upper limits distinctly, but the value of PT did not change noticeably. The in vitro antithrombogenicity represented the is activity-retaining form of antibodies. These results extend the application of antibody immobilization technique and provide a new idea about the design of biomaterials relating to the coagulation factors.

[In vitro and in vivo evaluation of the blood-biomaterial interaction]
Cenni, E., G. Ciapetti, et al. (1992), Minerva Cardioangiol 40(9): 297-316.
Abstract: The Authors, after a short description of the phenomena following the interaction between blood and biomaterials, take into consideration the different methods used in studying the in vitro, in vivo and ex vivo hemocompatibility, as well as the problems involved by each method and its contribution to the knowledge of hemocompatibility. The Authors report their experience on the in vitro study of the effects induced by some biomaterials on platelets and coagulation factors.

[Incisional hernia]
Conze, J., U. Klinge, et al. (2005), Chirurg 76(9): 897-909; quiz 910.
Abstract: With a long-term incidence of 10-20%, incisional hernias remain one of the most common surgical complications. Beside technical causes, wound-healing problems are increasingly being discussed. Conventional suture repair shows disappointing results and should be used only in selected cases. By the implantation of mesh prostheses, notable improvement could be achieved, with recurrence rates of <10%. Its main principle is retromuscular mesh reinforcement of the entire scar. Particularly in the neighbourhood of osseous structures, only retromuscular placement allows sufficient subduction of the mesh by healthy tissue of at least 5 cm in all directions. Preparation must take into account the special anatomic features of the abdominal wall, especially in the area of the Linea alba and Linea semilunaris.

[Infections associated with intra- and extravascular catheters: factors involved in microorganism-biomaterial interactions]
Baldassarri, L., A. Gelosia, et al. (1994), Ann Ist Super Sanita 30(2): 201-12.
Abstract: Infections is one of the most common cause of catheter failure as well as the most difficult to manage, most often requiring catheter removal. Staphylococcus is the etiologic agent of such infections more frequently isolated, particularly Staphylococcus epidermidis. Several factors have been suggested to be involved in bacteria-biomaterial interactions such as catheter surface morphology, molecular biofilm and bacterial virulence features. Different strategies have been tried to avoid the development to catheter-associated infections: among them adsorption of antibiotic molecules to the catheter surface might represent a successful tool to improve catheter implant life.

[Infections associated with the use of biomaterials in medicine]
Rozalska, B. (1994), Postepy Hig Med Dosw 48(2): 143-60.
Abstract: The paper deals with various problems related to foreign body infections. Such infections follow surgical replacements with orthopaedic or vascular prostheses or they are result of using catheters for diagnostic or treatment purposes. The list of most frequent microorganisms causing this kind of infections is presented and bacterial mechanisms enabling the colonization of biomaterials are described. The strategy for preparation of biomaterials which are better tolerated by human subjects and resistant to invading microorganisms is also presented.

[Influence of chitosan feeding of laying hens on egg vitamin and cholesterol content]
Vrzhesinskaia, O. A., I. V. Filimonova, et al. (2005), Vopr Pitan 74(3): 28-31.
Abstract: Chitosan feeding (10 and 20 mg per 1 kg body mass) of 19 week-age laying hens during 1.5 months caused a decrease in whole egg content of vitamin A for 13% and 20% (p < or = 0.05), vitamin E--for 30%, lutein--17% and didn't effect on vitamin B2 level. Chitosan intake lead to cholesterol content 1.5-2 fold decrease and didn't influence on egg yolk lipids concentration. Low dose chitosan-receiving hens had eggs with 1.8-fold increased egg yolk phospholipids level. The most optimal dose of chitosan for the improvement of eggs nutritive value was 10 mg. Under minimal loss in vitamins its administration lead to the pronounced cholesterol decrease and marked phospholipids elevation.

[Influence of different contact ways and extracting conditions on the hemolytic effect of biomaterials]
Sun, J., G. Gu, et al. (2003), Sheng Wu Yi Xue Gong Cheng Xue Za Zhi 20(1): 8-10.
Abstract: This assay was aimed to evaluate the influence of different contact ways and extracting conditions on the hemolytic effect of biomaterials. Using direct contact method and extract contact method, we assessed the hemolytic effect of PDLLA and PVC. The extracting conditions included: 37 degrees C 24 h, 37 degrees C 72 h, 37 degrees C 120 h, 50 degrees C 72 h, and 70 degrees C 24 h. After the material or extract had been in contact with the diluted blood of rabbit for certain times, the hemolysis rate was calculated. The results for PDLLA showed there were some differences between direct contact and extract contact at 37 degrees C for different extraction time (P < 0.05), but the hemolysis rates, lower than 5%, were in accord with the requirements of medical devices. However, under the condition of 50 degrees C and 70 degrees C, there were significant differences when extract contact method was compared with direct method (P < 0.01). For PVC, there was no statistically significant difference under all conditions (P > 0.05). Our conclusions: (1) Under the extracting condition of 37 degrees C from 24 h to 120 h, the soluble part of PDLLA and PVC that might influence erythrocyte did not dissolve considerably. (2) Under the extracting condition of 50 degrees C and 70 degrees C, the hemolysis rate may remarkably vary with the chemical characteristics of tested materials; (3) As to an unknown material, it is advisable to adopt two methods at the same time, one for direct contact and the other for extracontact. Thus the hemolytic effect of biomaterials can be evaluated from physical and chemical angles. (4) In case that the chemical property of the sample can endure the test, the extracting condition at 50 degrees C and 70 degrees C may be of benefit to assessing the hemolytic effect of biomaterials. (5) The extract contact method as a supplemental test of direct contact method is of realistic significance.

[Influence of different-sized titanium particles loading on osteoblastic differentiation and mineralization]
Wu, J., H. Chen, et al. (2005), Sheng Wu Yi Xue Gong Cheng Xue Za Zhi 22(1): 30-4.
Abstract: Studies have recently suggested that the coupling mechanism of bone formation and bone resorption are affected by particulate wear debris inducing aseptic loosening around the bone-prosthesis microenviroment. There may be direct impacts on osteoblasts, resulting in net decrease in bone formation. In addition, the influences of particulate wear debris in different size on the osteogenesis should be various. In order to investigate the hypothesis that particulate wear debris derived from prosthetic biomaterials affects the osteogenesis of osteblasts, we studied the influence of different-sized titanium particles loading on the osteoblastic differentiation by assaying the secretion of alkaline phosphatase (ALP), osteocalcin (OCN), N-terminal type I procollagen (PINP), and on the osteoblastic mineralization with the use of calcified node number, calcified node area and Alizarin Red S (ARS) concentration. Upon in vitro culture in the absence of titanium particles, we observed that cultures of osteoblasts isolated from newborn Japanese rabbits' cranium were excellently capable of differentiation and mineralization. Phi6.9 microm titanium particles did not evidently alter osteoblastic differentiation and mineralization. In comparison, phi2.7 microm and phi0.9 microm titanium particles, especially phi0.9 microm (submicron), significantly suppressed ALP expression, reduced PINP production, decreased OCN secretion and inhibited matrix mineralization. Results of transmission electron microscopy (TEM) of titanium particles-loaded osteoblastic cultures revealed that osteoblasts phagocytized titanium particles and exhibited ultrastructional changes consistent with cellular dysfuction. Combined with our previous studies in vitro findings, these results suggest that particles size play a key role in the process of aseptic loosening, which submicron particles are closely associated with inhibition of bone formation while bigger particles with enhancement of bone resorption. Further understanding the nature of osteoblastic bioreactivity to different-size wear particles should provide additional insights into mechanisms underlying aseptic loosening.

[Influence of implantation techniques on thromboresistance of biomaterial (author's transl]
Schladitz, G., H. Brauner, et al. (1979), Biomed Tech (Berl) 24(4): 70-5.

[Influence of intraocular lens material and design on the development of posterior capsule opacification]
Nishi, O. (2005), Ophthalmologe 102(6): 572-8.
Abstract: Based on the literature of 1999-2005, we attempted to clarify the influence of material and design of an intraocular lens (IOL) on the development of posterior capsule opacification (PCO) and identify the future problems to be solved. The sharp edge design of an IOL has significantly reduced PCO in recent years. Histopathological studies showed that a sharp capsular bend was formed at the sharp posterior optic edge, and the migration of lens epithelial cells was obviously inhibited at the site. Experimental and clinical studies suggest that the sharper the edge is, the sharper the capsular bend, and the greater the preventive effect, regardless of IOL material. The sharp capsule bend appears to represent a physical hindrance, which may induce contact inhibition of cell movement. How material participates in the preventive effect should be clarified in a future study. Thus, at the moment, the formation of capsular bend at the posterior optic edge appears to be the decisive criterion to evaluate the influence of IOL material and design on the development of PCO. Optimization of design and material of an IOL, which facilitates capsular bend formation as sharply and quickly as possible, may reduce PCO to a clinically negligible level.

[Inhibition activity of spirulina platensis proteins photo-immobilization biomaterial on proliferation of cancer cells]
Guan, Y. and B. Guo (2002), Sheng Wu Yi Xue Gong Cheng Xue Za Zhi 19(1): 1-3.
Abstract: The bioactive protein-phycocyanin and all the proteins of Spirulina Platensis were isolated and purified. Photo-reactive proteins were synthesized by coupling the proteins with (N-(4-azidobenzoyloxy)succinimide) and were spread onto the 24-well cell culture polystyrene plate. Then the coated surface was exposed to ultraviolet irradiation for chemical fixation of proteins via the conversion of the phenylazido group to the highly reactive phenyl-nitrene which spontaneously formed covalent bonds with neighboring hydrocarbons. On these proteins-immobilized polystyrene plates, the liver cancer cells 7402 were cultured under the serum-free conditions, and the inhibition activity on proliferation of liver cancer cells was investigated and analyzed.

[Inorganic biomaterials in endodontic therapy (2). Histo-pathological studies of the effect of alumina ceramic powder on the apical wounds of dog teeth]
Ariizumi, Y., M. Hinoide, et al. (1984), Shikwa Gakuho 84(9): 1603-13.

[Interactions between blood and biomaterials. Applications to extracorporeal circulation]
Doutremepuich, C. (1982), Pathol Biol (Paris) 30(8): 677-9.

[Interdisciplinary centers for clinical research. Biomaterials: the focal point in Aachen]
Sander, A. (2000), Dtsch Med Wochenschr 125(27): A15-8.

[Interdisciplinary research at the "Lions Eye Institute" of Western Australia and the development of ophthalmic biomaterials]
Chirila, T. V. (2002), Arch Soc Esp Oftalmol 77(5): 235-7.

[Interest of porous biomaterials in spinal surgery.]
Finiels, P. J. (2004), Neurochirurgie 50(6): 630-8.
Abstract: PURPOSE OF THE STUDY: The aim of this work was to study the behavior of porous alumina ceramic cages in spinal cervical surgery, with or without plate fixation as needed. MATERIAL AND METHODS: The population included 61 patients who underwent spinal surgery between May 1999 and October 2003. There were 48 women and 13 men, mean age 49 years at surgery. 74 implants were used, among them 71 were interbody cages. Ten patients were operated at two levels; C5-C6 and C6-C7 were most frequently instrumented. Patients were reviewed at 1 month, 3 months and 6 months, and, whenever possible more after. Clinical and radiological data were available for all patients. RESULTS: Mean follow-up was 7.2 months. Postoperative clinical data included assessment of neck and arm pain, using a visual analogic scale and fusion status determined by the presence of trabecular bridging bone and the disappearance of lucent lines around the implant on plain anteroposterior and lateral cervical radiographs. Two patients required another intervention, allowing intra-operative assessment of the quality of fusion. Clinical results were in agreement with the usual outcome reported in the literature with 54% of patients free of postoperative neck or arm pain and restriction of function mild or absent in 88%. Bone healing was achieved at 6 months on the average in 58 cases and in all patients at 12 months, including the two patients who required revision. DISCUSSION: The porous alumine cage is a reliable biocompatible and mechanically stable element helpful for achieving bone healing. Integration into bone tissue was radiographically satisfactory. This kind of implant appears to be an attractive alternative in spinal cervical surgery, avoiding donor graft site complications.

[Intraluminal splinting of problematic intestinal anastomoses with biomaterial tubes]
Winkeltau, G., K. H. Treutner, et al. (1989), Langenbecks Arch Chir 374(1): 32-8.
Abstract: We performed small intestinal dissection in 80 laboratory rats. A critical anastomosis was achieved by two point adaptation of small intestine with single sutures. 10 control animals receiving no intestinal splinting died within two days of operation. The remaining 70 animals underwent intestinal internal splinting with tubes of different absorbable (Polyglactine, Collagen, and B111) and non-absorbable (Polyurethane) biomaterials. Significantly smaller leakage rates in the therapy groups proved the principle of internal splinting of complicated anastomoses in this animal model to be effective.

[Intraperitoneal placement of composite implants--polyester mesh coated with polyurethane in experimental study]
Chobola, M., Z. Voboril, et al. (2005), Rozhl Chir 84(3): 128-33.
Abstract: INTRODUCTION: Polyester and polypropylene are currently the most frequently materials for repair of abdominal wall hernias. Most of the mesh materials used intraperitoneally in repair of hernias lead to considerable adhesion formation, as well as the resultant bowel obstruction and intestinal fistula formation. Some newer composite products can reduce risk of adhesion formation. The aim of this experimental study is testing properties of patch, composite structure, characterised by the association of a non-woven textile structure made from polyester multifilaments, and a fine coat of polyurethane on one side, placed intraperitoneally in rat. MATERIALS AND METHODS: The experiment was carried out with 21 laboratory rats. Laboratory animals were divided into 3 groups - 7 animals in a group. In the first group the check-up laparotomy was realized the 7th day, in the second group the 14th day and in the third group the 28th day after the intraperitoneal implantation of a composite mesh. All animals were sacrificed and adhesion scoring and histological evaluation of tissue specimens with implanted mesh were done. RESULTS: A macroporous polyester mesh component supported an early and huge fibrous proliferation with a good adhesion onto the abdomen wall. On the other hand, a microporous polyurethane layer led to the creation of a fibrous pocket. During the check-up laparotomy, the larger adhesion of omentum to the fibrous layer, covering the polyurethane side of implanted mesh, were located in most laboratory rats - in all the groups. CONCLUSION: We can presume that the protective polyurethane layer does not eliminate risk of adhesion formation in rat.

[Intraurethral injections of Zuidex: evaluation of the morbidity of the technique in the treatment of female urinary incontinence]
Ferchaud, J., F. Girard, et al. (2005), Prog Urol 15(3): 494-7.
Abstract: OBJECTIVE: To evaluate the feasibility and morbidity of intraurethral injections of dextranomer/hyaluronic acid (Zuidex), performed under local anaesthesia as an outpatient procedure in the treatment of female urinary incontinence. MATERIAL AND METHODS: Twenty one patients with a mean age of 67 years (range: 29-93 years) presenting urinary incontinence related to sphincter incompetence were treated by intraurethral injection of Zuidex. Injections were performed with the Implacer system provided with the product under local anaesthesia. RESULTS: For nine of these patients (43%), a second injection after 6 weeks was performed due to an insufficient result on incontinence. A total of 30 injections were therefore performed. No significant problem was observed during the injections. Three injections (10%) were difficult because of a short urethra. In 7 cases (23%), the patient reported pain during the injection. In 3 cases (10%), macroscopic haematuria was observed after treatment and another 4 cases (13%) developed lower urinary tract infection. Six patients (20%) developed transient acute urinary retention with resumption of micturition after 24 to 48 hours. CONCLUSION: Intraurethral injection of Zuidex has the advantage of being minimally invasive and can be performed under local anaesthesia, as an outpatient procedure, with good safety and a low complication rate. Resumption of spontaneous voiding must be monitored in view of the risk of urinary retention. The long-term results have not yet been evaluated.

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