bone construct
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Differences in microscopic structure of the femur between 1-month-old transgenic rabbits carrying the hFVIII gene and non-transgenic rabbits were investigated. Bone microstructure was evaluated from the point of view of qualitative and quantitative histological characteristics. We identified fibrolamellar bone tissue only in the transgenic animals. Measured values for area, perimeter of the Haversian canals and minimum diameter of the primary osteons' vascular canals were higher in 1-month-old transgenic individuals (P < 0.05; P < 0.001). We also observed lower concentrations of Ca, P, K, solids, and total mineral content in femora of transgenic rabbits. A statistically significant difference was observed for the concentration of Ca (P < 0.05). Our results indicate evident changes in both qualitative and quantitative histological characteristics of the femur, which result especially in better blood supply and slightly reduced mineralization process in 1-month-old transgenic rabbits.
- MeSH
- faktor VIII genetika MeSH
- femur cytologie MeSH
- fyziologická kalcifikace MeSH
- geneticky modifikovaná zvířata MeSH
- kostní denzita MeSH
- králíci MeSH
- lidé MeSH
- mléčné bílkoviny genetika MeSH
- novorozená zvířata MeSH
- zvířata MeSH
- Check Tag
- králíci MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
PURPOSE: The cement augmentation of a conventional anterior screw fixation in type II odontoid process fractures for elderly patients significantly increased stiffness and load to failure under anterior-posterior load in comparison with non-augmented fixation. The amount and quality of bone cement are usually taken ad hoc in clinical practise. In this study, we wanted to clarify the role of bone cement amount and its quality to the stiffness of odontoid and vertebrae body junction. METHODS: Finite-element method was used to achieve different scenarios of cement augmentation. For all models, an initial stiffness was calculated. Model (1) the intact vertebrae were virtually potted into a polymethylmethacrylate base via the posterior vertebral arches. A V-shaped punch was used for loading the odontoid in an anterior-posterior direction. (2) The odontoid fracture type IIa (Anderson-D'Alonzo classification) was achieved by virtual transverse osteotomy. Anterior screw fixation was virtually performed by putting self-drilling titanium alloy 3.5 mm diameter anterior cannulated lag screw with a 12 mm thread into the inspected vertebrae. A V-shaped punch was used for loading the odontoid in an anterior-posterior direction. The vertebrae body was assumed to be non-cemented and cemented with different volume. RESULTS: The mean cement volume was lowest for body base filling with 0.47 ± 0.03 ml. The standard body filling corresponds to 0.95 ± 0.15 ml. The largest volume corresponds to 1.62 ± 0.12 ml in the presence of cement leakage. The initial stiffness of the intact C2 vertebrae was taken as the reference value. The mean initial stiffness for non-porous cement (E = 3000 MPa) increased linearly (R2 = 0.98). The lowest stiffness (123.3 ± 5.8 N/mm) was measured in the intact C2 vertebrae. However, the highest stiffness (165.2 ± 5.2 N/mm) was measured when cement leakage out of the odontoid peg occurred. The mean initial stiffness of the base-only cemented group was 147.2 ± 8.4 N/mm compared with 157.9 ± 6.6 N/mm for the base and body cemented group. This difference was statistically significant (p < 0.0061). The mean initial stiffness for porous cement (E = 500 MPa) remains constant. Therefore, there is no difference between cemented and non-cemented junction. This difference was not statistically significant (p < 0.18). CONCLUSION: The present study showed that the low porous cement was able to significantly influence the stiffness of the augmented odontoid screw fixation in vitro, although further in vivo clinical studies should be undertaken. Our results suggest that only a small amount of non-porous cement is needed to restore stiffness at least to its pre-fracture level and this can be achieved with the injection of 0.7-1.2 ml of cement. These slides can be retrieved under Electronic Supplementary Material.
- MeSH
- dens axis * diagnostické zobrazování zranění chirurgie MeSH
- fraktury páteře * diagnostické zobrazování chirurgie MeSH
- kostní cementy terapeutické užití MeSH
- kostní šrouby MeSH
- lidé MeSH
- senioři MeSH
- vnitřní fixace fraktury MeSH
- Check Tag
- lidé MeSH
- senioři MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The aim was to construct a composite structure for bone tissue substitute on the basis of a degradable composite of an organic nanofiber carrier and an inorganic matrix in 3D, and to achieve subsequent colonisation by differentiated human mesenchymal stem cells (hMSC) towards osteocytes. We developed an active bone tissue substitute using nanofiber technology for a polycaprolactone (PCL) scaffold with the addition of hydroxyapatite and the colonisation of both components with hMSC with the ability of differentiation towards osteocytes. The constructed composition included the components necessary for bone healing (inorganic and cellular) and it also forms a spatially-oriented 3D structure. We used polycaprolactone Mw 70,000 with electrostatic spinning for the formation of nanofibers using a modified NanospiderTM method. For the inorganic component we used orthophosphate-calcium silicate with a crystal size of 1-2 mm which the nanofiber membrane was coated with. Both components were connected together with a tissue adhesive based of fibrin glue. Cultivated hMSC cells at a concentration of 1.2 × 104/cm2 were multiplied in vitro and then cultivated in the expansion medium. HMSC overgrew both the PCL membrane and the Si-CaP crystals. After colonisation with cultivated cells, this composite 3D structure can serve as a three-dimensional bone tissue replacement.
- Klíčová slova
- polykaprolakton,
- MeSH
- hydroxyapatity MeSH
- kostní náhrady * chemie klasifikace MeSH
- lidé MeSH
- mezenchymální kmenové buňky MeSH
- nanovlákna MeSH
- techniky in vitro MeSH
- vstřebatelné implantáty MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
Revizní operace acetabula, spojené s úbytkem kostní hmoty, jsou složitým úkolem. Rekonstrukce s použitím ilioischiálního prstence v kombinaci s morselizovanými kostními štěpy kosti je účinným postupem při léčbě rozsáhlé ztráty kostní tkáně acetabula. Největší problémy představují defekty typů IIIA a IIIB Paproskyho klasifikace (typy III a IV podle AAOS). V klinice používáme Burchův-Schneiderův prstenec od roku 1994. Antiprotruzním prstencem s kostními štěpy může být dosaženo dostatečné augmentace kosti, konstrukce zároveň umožňuje obnovit střed kyčle do anatomické polohy. Implantát podporuje integraci kostních štěpů v důsledku snížení mechanického namáhání. Burchův-Schneiderův antiprotruzní prstenec je srovnatelný s ostatními implantáty tohoto typu s ohledem na dlouhodobé přežití implantátu. V tomto sdělení shrnujeme naše zkušenosti dosažené s tímto implantátem spolu s posledními údaji z literatury.
Revision surgeries of the acetabulum associated with bone loss, are a complicated task. Acetabular reconstruction with use of morselized allogenic cancellous bone graft and the Burch-Schneider cage can be highly successful in management of massive acetabular deficiencies in revision hip arthroplasty. The most serious problems are caused by defects of the types IIIA and IIIB as per Paprosky classification (type III. and IV. according to AAOS). In our department we use the Burch-Schneider ring since 1994. Anti-protrusion cages in combination with bone grafts can achieve sufficient bone augmentation, the construct helps to restore the centre of the hip to its proper anatomical position. The implant supports the integration of bone grafts due to reduced mechanical stress. Burch-Schneider anti-protrusion cage is comparable to other implants of this type with regard to the long term survival. In this paper we summarize our experience with the implant and review data from recent literature.
- Klíčová slova
- rekonstrukce acetabula, Burchův-Schneiderův prstenec,
- MeSH
- acetabulum * chirurgie MeSH
- homologní transplantace MeSH
- kyčelní protézy MeSH
- lidé MeSH
- náhrada kyčelního kloubu * metody MeSH
- pooperační komplikace MeSH
- protézy - design MeSH
- reoperace * metody přístrojové vybavení statistika a číselné údaje MeSH
- selhání protézy MeSH
- transplantace kostí MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- přehledy MeSH
The purpose of this study was to investigate biocompatibility of the human mesenchymal stem cells with bovine bone tissue at the cellular level in vitro. Phenotypic analysis of cells was made by flow cytometry. Cells were grown on the bone for 12 days. Metabolic activity of cells was assessed with the MTS assay. The growth data were used to calculate the population doubling times. The scanning electron microscopy was used to verify the attachment of cells on the bone surface. The results were analyzed by using ANOVA test. Immunophenotypic characteristics were positive for CD105, CD90, CD73, and negative for CD34, CD45. The growth curves of stem cells of the 1st and the 2nd passages for both media, with and without, bovine bone were constructed. The increase of approximately 60% of the doubling time for mesenchymal cells co-cultivated with bovine bone tissue was observed for both passages in comparison with the control.Our study confirmed that mesenchymal stem cells are able to adhere to the bovine bone, even not being modified with bone-targeting elements. The proliferation rate and metabolic activity of cells co-cultivated with bone decrease in comparison with the control. Better survival was observed for cells of the 1st passage.
The widespread introduction of dental implant in the dental practice will determine progress and the future of prosthetic dentistry. At the same time, like any new direction dental implantation has generated a lot of questions and unsolved problems. On many of these issues and problems can be answered only by using morphological methods. Therefore, after the development of a new construction of the dental implant one of the main issues was the question of its interaction with the jawbone and soft tissues of the oral cavity. We performed the experiment on 24 long snout dogs of both sexes, weighing 30-35 kg, with normal bite, at the age of 20-24 months. Animals were divided into 2 groups, according to samples of screw dental implants used in the experiment: basic group - 12 dogs in which were used samples of the new construction of dental implant “Implant.uz” (Uzbekistan); control group – 12 dogs in which were applied screw dental implant system “Dentium” (South Korea). Terms of derivation of animals from experiments were 1, 3, and 6 months. By using morphological techniques were studied implants “Implant.uz” from medical titanium BT-1.00 brand, their interaction with bone of alveolar ridge. “Implant.uz” did not cause pathological changes in the bone tissue of alveolar ridges of jaws and could be an alternative to known dental implants.
The purpose of this study was to investigate the effect of load-induced local mechanical strain on bone cell activity of peri-implant bone in mice. Titanium implants were placed in the maxillae of 13-week-old male C57BL/6J mice and subjected to intermittent 0.15 N, 0.3 N, or 0.6 N loads for 30 min/day for 6 days. The animals were sacrificed 2 days after the final loading. Unloaded mice were used as controls. An animal-specific three-dimensional finite element model was constructed based on morphological data retrieved from in vivo microfocus computed tomography for each mouse to calculate the mechanical strain distribution. Strain distribution images were overlaid on corresponding histological images of the same site in the same animal. The buccal cervical region of the peri-implant bone was predetermined as the region of interest (ROI). Each ROI was divided by four strain intensity levels: 0-20 με, 20-60 με, 60-100 με, and ≥100 με, and the bone histomorphometric parameters were analyzed by the total area of each strain range for all loaded samples. The distance between the calcified front and calcein labeling as a parameter representing the mineral apposition rate was significantly greater in the areas with strain intensity ≥100 με than in the area with strain intensity <100 με, suggesting that the bone formation activity of osteoblasts was locally enhanced by a higher mechanical strain. However, the shrunken osteocytes and the empty osteocyte lacunae were significantly lower in the highest strain area, suggesting that osteoclastogenesis was more retarded in higher strain areas than in lower strain areas. The histomorphometric parameters were not affected geometrically in the unloaded animals, suggesting that the load-induced mechanical strain caused differences in the histomorphometric parameters. Our findings support the hypothesis that bone cell activity related to bone resorption and formation is local strain-dependent on implant loading.
The mid-term longevity of femoral components varies considerably, with some showing failure due to early aseptic loosening. Since the hip joint is subject to heavy mechanical loads, it can be assumed that the mechanical interaction of the implant, bone cement and femur will play a key role in the resultant reliability of an arthroplasty. This study was designed to examine this mechanical interaction in four femoral components different in construction (Poldi-Cech, CF-30, MS-30 and PFC) using mathematical simulation. MATERIAL AND METHODS Four stem/cement/femur 3-D mathematical models, comparable in quality, infolving the Poldi-Cech, CF-30, MS-30 and PFC stems, respectively, were constructed. A 3-D model for each stem was created according to its real, middle-size femoral component. Each 3-D model of the cement mantle corresponded in shape to the mantle of the appropriate real stem, with its thickness based on the recommended values of 4-7 mm in the proximal and 1-3 mm in the distal part, and with the cement mantle reaching as far as 10 mm distal to the femoral stem tip. For simplicitys sake the outer surface of the cement mantle was simulated as smooth. A 3-D model involving the proximal epiphysis and the metaphysis of a femur was reconstructed, based on a series of CT cross-sections obtained periodically at 10.5-mm and 2.5-mm distances. The sten/cement/femur model with the MS-30 stem also included a centraliser. The mechanical interaction of the stem, bone cement and bone tissue was examined by means of mathematical stimulation using ANSYS 5.7 software based on finite element analysis. RESULTS For the sake of simplicity, only two key parameters are presented, namely, contact stress at the stem-cement interface and equivalent deformation in the stem/cement/femur system. The least satisfactory stress loading was in the CF-30 stem whose sharp edges showed the values of contact stress about six-times higher than on the mid-medial portion of the stem, with the sharp edges behaving as stress concentrators. A satisfactory stress loading was found in Poldi-Cech, MS-30 and PFC stems, in which contact stress was evenly distributed along the whole lenght of the stem and the values at the edges and on the midmedial portion did not differ much. DISCUSSION The distribution of contact stress is one of the most important factors for the long-term longevity of implants. It was found least satisfactory in the CF-30 stem whose sharp edges act as stress condenser adversely affecting not only the stemcement interface, but also the resultant stress distribution within the femur. The most satisfactory results of stress distribution were recorded in the Poldi-Cech and MS-30 stems. The PFC stem also responded satisfactorily to the simulated stress loading. However, on loading whose substantial part would be torsion, the stems circular or oval cross-section could interfere with rotation stability of the implant; but this was impossible to detect by the mathematical simulation used in this study. CONCLUSIONS The results presented here show that, in the Poldi-Cech, CF-30, MS-30 and PFC femoral stems, a good agreement was achieved between the results of their clinical application and those of mathematical modelling of their mechanical properties. It can be concluded that mechanical interaction among the femoral stem, cement mantle and bone tissue plays the key role in the long-term longevity of such an implant. Key words: Poldi-Cech, CF-30, MS-30, PFC, mechanical interaction, contact stress.
- MeSH
- femur MeSH
- kostní cementy MeSH
- kyčelní protézy MeSH
- lidé MeSH
- mechanický stres MeSH
- počítačová simulace MeSH
- Check Tag
- lidé MeSH
The opinion regarding the origin of adult stem cells that should be used for living bone construct generation is strongly divided in the scientific community. In this study, the potential of chitosan/β-1,3-glucan/hydroxyapatite (chit/glu/HA) material as a scaffold for bone regeneration applications was evaluated by behaviour comparison of adult stem cells derived from both origins-adipose derived mesenchymal stem cell (ADSC) tissue and bone marrow derived mesenchymal stem cells (BMDSCs). In the case of ADSC isolation, low and high negative pressures were applied during a liposuction procedure in order to determine if negative pressure settings may have an impact on subsequent cell behaviour in vitro. The obtained results demonstrated that the chit/glu/HA material is a promising candidate to be used for living bone graft production in vitro as both ADSCs and BMDSCs revealed a satisfactory proliferation and differentiation ability on its surface. Nevertheless, BMDSCs would be a better choice of adult stem cells since they were better spread, more strongly attached and showed a more superior proliferation and differentiation ability than ADSCs when cultured on the chit/glu/HA scaffold. However, if BMDSCs cannot be isolated, ADSCs may be used for bone construct production but lipoaspirate should be collected under low negative pressure (-200 mm Hg), as high negative pressure (-700 mmHg) applied during liposuction surgery may retard subsequent ADSC proliferation and type I collagen production.
- MeSH
- beta-glukany chemie MeSH
- biokompatibilní materiály chemie MeSH
- buněčná diferenciace MeSH
- chitosan chemie MeSH
- fokální adheze MeSH
- hydroxyapatit chemie MeSH
- kultivované buňky MeSH
- lidé MeSH
- mezenchymální kmenové buňky cytologie fyziologie MeSH
- osteogeneze MeSH
- pohyb buněk MeSH
- proliferace buněk MeSH
- regenerace kostí MeSH
- testování materiálů MeSH
- tkáňové podpůrné struktury chemie MeSH
- tuková tkáň cytologie MeSH
- Check Tag
- lidé MeSH
