Various studies have correlated the mechanical properties of the aortic wall with its biochemical parameters and inner structure. Very few studies have addressed correlations with the cohesive properties, which are crucial for understanding fracture phenomena such as aortic dissection, i.e. a life-threatening process. Aimed at filling this gap, we conducted a comprehensive biochemical and histological analysis of human aortas (the ascending and descending thoracic and infrarenal abdominal aorta) from 34 cadavers obtained post-mortem during regular autopsies. The pentosidine, hydroxyproline and calcium contents, calcium/phosphorus molar ratio, degree of atherosclerosis, area fraction of elastin, collagen type I and III, alpha smooth muscle actin, vasa vasorum, vasa vasorum density, aortic wall thickness, thicknesses of the adventitia, media and intima were determined and correlated with the delamination forces in the longitudinal and circumferential directions of the vessel as determined from identical cadavers. The majority of the parameters determined did not indicate significant correlation with age, except for the calcium content and collagen maturation (enzymatic crosslinking). The main results concern differences between enzymatic and non-enzymatic crosslinking and those caused by the presence of atherosclerosis. The enzymatic crosslinking of collagen increased with age and was accompanied by a decrease in the delamination strength, while non-enzymatic crosslinking tended to decrease with age and was accompanied by an increase in the delamination strength. As the rate of calcification increased, the presence of atherosclerosis led to the formation of calcium phosphate plaques with higher solubility than the tissue without or with only mild signs of atherosclerosis. STATEMENT OF SIGNIFICANCE: This study presents a detailed biochemical and histological analysis of human aortic samples (ascending thoracic aorta, descending thoracic aorta and infrarenal abdominal aorta) taken from 34 cadavers. The contribution of this scientific study lies in the detailed biochemical comparison of the enzymatic and non-enzymatic glycosylation-derived crosslinks of vascular tissues and their influence on the delamination strength of the human aorta since, to the best of our knowledge, no such comprehensive studies exist in the literature. A further benefit concerns the notification of the limitations of the various analytical methods applied; an important factor that must be taken into account in such studies.
- MeSH
- aktiny metabolismus MeSH
- aorta * metabolismus MeSH
- arginin analogy a deriváty MeSH
- ateroskleróza metabolismus patologie MeSH
- dospělí MeSH
- elastin metabolismus MeSH
- hydroxyprolin metabolismus MeSH
- lidé středního věku MeSH
- lidé MeSH
- lysin analogy a deriváty metabolismus MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- stárnutí * fyziologie MeSH
- vápník metabolismus MeSH
- vasa vasorum metabolismus MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- MeSH
- fibrilace komor etiologie terapie MeSH
- lidé MeSH
- mladý dospělý MeSH
- multiorgánové selhání etiologie MeSH
- otrava rostlinami * patofyziologie terapie MeSH
- pokus o sebevraždu MeSH
- taxoidy otrava MeSH
- tis * otrava MeSH
- Check Tag
- lidé MeSH
- mladý dospělý MeSH
- Publikační typ
- kazuistiky MeSH
The aim of the study was to develop an orthopedic implant coating in the form of vancomycin-loaded collagen/hydroxyapatite layers (COLHA+V) that combine the ability to prevent bone infection with the ability to promote enhanced osseointegration. The ability to prevent bone infection was investigated employing a rat model that simulated the clinically relevant implant-related introduction of bacterial contamination to the bone during a surgical procedure using a clinical isolate of Staphylococcus epidermidis. The ability to enhance osseointegration was investigated employing a model of a minipig with terminated growth. Six weeks following implantation, the infected rat femurs treated with the implants without vancomycin (COLHA+S. epidermidis) exhibited the obvious destruction of cortical bone as evinced via a cortical bone porosity of up to 20% greater than that of the infected rat femurs treated with the implants containing vancomycin (COLHA+V+S. epidermidis) (3%) and the non-infected rat femurs (COLHA+V) (2%). The alteration of the bone structure of the infected COLHA+S. epidermidis group was further demonstrated by a 3% decrease in the average Ca/P molar ratio of the bone mineral. Finally, the determination of the concentration of vancomycin released into the blood stream indicated a negligible systemic load. Six months following implantation in the pigs, the quantified ratio of new bone indicated an improvement in osseointegration, with a two-fold bone ingrowth on the COLHA (47%) and COLHA+V (52%) compared to the control implants without a COLHA layer (27%). Therefore, it can be concluded that COLHA+V layers are able to significantly prevent the destruction of bone structure related to bacterial infection with a minimal systemic load and, simultaneously, enhance the rate of osseointegration.
- Publikační typ
- časopisecké články MeSH
The aim of this study was to develop a biodegradable nanostructured electrospun layer based on collagen (COL), hydroxyapatite nanoparticles (HA), vancomycin hydrochloride (V), gentamicin sulphate (G) and their combination (VG) for the treatment of prosthetic joint infections and the prevention of infection during the joint replacement procedure. COL/HA layers containing different amounts of HA (0, 5 and 15 wt%) were tested for the in vitro release kinetics of antibiotics, antimicrobial activity against MRSA, gentamicin-resistant Staphylococcus epidermidis and Enterococcus faecalis isolates and cytocompatibility using SAOS-2 bone-like cells. The results revealed that the COL/HA layers released high concentrations of vancomycin and gentamicin for 21 days and performed effectively against the tested clinically-relevant bacterial isolates. The presence of HA in the collagen layers was found not to affect the release kinetics of the vancomycin from the layers loaded only with vancomycin or its combination with gentamicin. Conversely, the presence of HA slowed down the release of gentamicin from the COL/HA layers loaded with gentamicin and its combination with vancomycin. The combination of both antibiotics exerted a positive effect on the prolongation of the conversion of vancomycin into its degradation products. All the layers tested with different antibiotics exhibited potential antibacterial activity with respect to both the tested staphylococci isolates and enterococci. The complemental effect of vancomycin was determined against both gentamicin-resistant Staphylococcus epidermidis and Enterococcus faecalis in contrast to the application of gentamicin as a single agent. This combination was also found to be more effective against MRSA than is vancomycin as a single agent. Importantly, this combination of vancomycin and gentamicin in the COL/HA layers exhibited sufficient cytocompatibility to SAOS-2, which was independent of the HA content. Conversely, only gentamicin caused the death of SAOS-2 independently of HA content and only vancomycin stimulated SAOS-2 behaviour with an increased concentration of HA in the COL/HA layers. In conclusion, COL/HA layers with 15 wt% of HA impregnated with vancomycin or with a combination of vancomycin and gentamicin offer a promising treatment approach and the potential to prevent infection during the joint replacement procedures.
- MeSH
- antibakteriální látky chemie farmakologie MeSH
- buněčné linie MeSH
- Enterococcus faecalis účinky léků MeSH
- gentamiciny chemie farmakologie MeSH
- hydroxyapatit chemie MeSH
- infekce spojené s protézou mikrobiologie prevence a kontrola MeSH
- kinetika MeSH
- kolagen chemie MeSH
- kostní cementy chemie MeSH
- lidé MeSH
- methicilin rezistentní Staphylococcus aureus účinky léků MeSH
- mikrobiální testy citlivosti metody MeSH
- Staphylococcus epidermidis účinky léků MeSH
- synergismus léků MeSH
- vankomycin chemie farmakologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Collagen composite scaffolds have been used for a number of studies in tissue engineering. The hydration of such highly porous and hydrophilic structures may influence mechanical behaviour and porosity due to swelling. The differences in physical properties following hydration would represent a significant limiting factor for the seeding, growth and differentiation of cells in vitro and the overall applicability of such hydrophilic materials in vivo. Scaffolds based on collagen matrix, poly(DL-lactide) nanofibers, calcium phosphate particles and sodium hyaluronate with 8 different material compositions were characterised in the dry and hydrated states using X-ray microcomputed tomography, compression tests, hydraulic permeability measurement, degradation tests and infrared spectrometry. Hydration, simulating the conditions of cell seeding and cultivation up to 48 h and 576 h, was found to exert a minor effect on the morphological parameters and permeability. Conversely, hydration had a major statistically significant effect on the mechanical behaviour of all the tested scaffolds. The elastic modulus and compressive strength of all the scaffolds decreased by ~95%. The quantitative results provided confirm the importance of analysing scaffolds in the hydrated rather than the dry state since the former more precisely simulates the real environment for which such materials are designed.
- MeSH
- biokompatibilní materiály chemie MeSH
- fosforečnany vápenaté chemie MeSH
- kolagen chemie MeSH
- kyselina hyaluronová chemie MeSH
- mechanické jevy MeSH
- modul pružnosti MeSH
- pevnost v tlaku MeSH
- polyestery chemie MeSH
- poréznost MeSH
- rentgenová mikrotomografie MeSH
- testování materiálů MeSH
- tkáňové inženýrství metody MeSH
- tkáňové podpůrné struktury chemie MeSH
- voda chemie MeSH
- vysoušení * MeSH
- Publikační typ
- časopisecké články MeSH
The aim of this study was to develop an osteo-inductive resorbable layer allowing the controlled elution of antibiotics to be used as a bone/implant bioactive interface particularly in the case of prosthetic joint infections, or as a preventative procedure with respect to primary joint replacement at a potentially infected site. An evaluation was performed of the vancomycin release kinetics, antimicrobial efficiency and cytocompatibility of collagen/hydroxyapatite layers containing vancomycin prepared employing different hydroxyapatite concentrations. Collagen layers with various levels of porosity and structure were prepared using three different methods: by means of the lyophilisation and electrospinning of dispersions with 0, 5 and 15wt% of hydroxyapatite and 10wt% of vancomycin, and by means of the electrospinning of dispersions with 0, 5 and 15wt% of hydroxyapatite followed by impregnation with 10wt% of vancomycin. The maximum concentration of the released active form of vancomycin characterised by means of HPLC was achieved via the vancomycin impregnation of the electrospun layers, whereas the lowest concentration was determined for those layers electrospun directly from a collagen solution containing vancomycin. Agar diffusion testing revealed that the electrospun impregnated layers exhibited the highest level of activity. It was determined that modification using hydroxyapatite exerts no strong effect on vancomycin evolution. All the tested samples exhibited sufficient cytocompatibility with no indication of cytotoxic effects using human osteoblastic cells in direct contact with the layers or in 24-hour infusions thereof. The results herein suggest that nano-structured collagen-hydroxyapatite layers impregnated with vancomycin following cross-linking provide suitable candidates for use as local drug delivery carriers.
- MeSH
- antibakteriální látky * aplikace a dávkování chemie MeSH
- hydroxyapatit * aplikace a dávkování chemie MeSH
- kolagen * aplikace a dávkování chemie MeSH
- krevní plazma chemie MeSH
- lékové transportní systémy * MeSH
- lidé MeSH
- nádorové buněčné linie MeSH
- nanostruktury aplikace a dávkování chemie MeSH
- osteoblasty účinky léků MeSH
- Staphylococcus aureus účinky léků MeSH
- Staphylococcus epidermidis účinky léků MeSH
- vankomycin * aplikace a dávkování chemie MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
Infections of the musculoskeletal system present a serious problem with regard to the field of orthopedic and trauma medicine. The aim of the experiment described in this study was to develop a resorbable nanostructured composite layer with the controlled elution of antibiotics. The layer is composed of collagen, hydroxyapatite nanoparticles, and vancomycin hydrochloride (10 wt%). The stability of the collagen was enhanced by means of cross-linking. Four cross-linking agents were studied, namely an ethanol solution, a phosphate buffer solution of N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride/N-hydroxysuccinimide, genipin, and nordihydroguaiaretic acid. High performance liquid chromatography was used so as to characterize the in vitro release rates of the vancomycin and its crystalline degradation antibiotically inactive products over a 21-day period. The maximum concentration of the released active form of vancomycin (approximately 265 mg/L) exceeded the minimum inhibitory concentration up to an order of 17 times without triggering the burst releasing effect. At the end of the experiment, the minimum inhibitory concentration was exceeded by up to 6 times (approximately 100 mg/L). It was determined that the modification of collagen with hydroxyapatite nanoparticles does not negatively influence the sustainable release of vancomycin. The balance of vancomycin and its degradation products was observed after 14 days of incubation.
- MeSH
- hydroxyapatit MeSH
- karbodiimidy chemie MeSH
- kolagen chemie MeSH
- lékové transportní systémy metody MeSH
- léky s prodlouženým účinkem chemie MeSH
- methylaminy chemie MeSH
- nanočástice chemie MeSH
- nanostruktury chemie MeSH
- nosiče léků chemie MeSH
- vankomycin chemie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Nanocomposite scaffolds which aimed to imitate a bone extracellular matrix were prepared for bone surgery applications. The scaffolds consisted of polylactide electrospun nano/sub-micron fibres, a natural collagen matrix supplemented with sodium hyaluronate and natural calcium phosphate nano-particles (bioapatite). The mechanical properties of the scaffolds were improved by means of three different cross-linking agents: N-(3-dimethylamino propyl)-N'-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide in an ethanol solution (EDC/NHS/EtOH), EDC/NHS in a phosphate buffer saline solution (EDC/NHS/PBS) and genipin. The effect of the various cross-linking conditions on the pore size, structure and mechanical properties of the scaffolds were subsequently studied. In addition, the mass loss, the swelling ratio and the pH of the scaffolds were determined following their immersion in a cell culture medium. Furthermore, the metabolic activity of human mesenchymal stem cells (hMSCs) cultivated in scaffold infusions for 2 and 7 days was assessed. Finally, studies were conducted of cell adhesion, proliferation and penetration into the scaffolds. With regard to the structural stability of the tested scaffolds, it was determined that EDC/NHS/PBS and genipin formed the most effectively cross-linked materials. Moreover, it was discovered that the genipin cross-linked scaffold also provided the best conditions for hMSC cultivation. In addition, the infusions from all the scaffolds were found to be non-cytotoxic. Thus, the genipin and EDC/NHS/PBS cross-linked scaffolds can be considered to be promising biomaterials for further in vivo testing and bone surgery applications.
- MeSH
- analýza selhání vybavení MeSH
- biokompatibilní materiály chemická syntéza MeSH
- buněčná adheze fyziologie MeSH
- design vybavení MeSH
- kolagen chemie MeSH
- kostní matrix chemie MeSH
- kostní náhrady chemická syntéza MeSH
- lidé MeSH
- mezenchymální kmenové buňky cytologie fyziologie MeSH
- nanokompozity chemie ultrastruktura MeSH
- proliferace buněk fyziologie MeSH
- reagencia zkříženě vázaná chemie MeSH
- testování materiálů MeSH
- tkáňové podpůrné struktury * MeSH
- transplantace mezenchymálních kmenových buněk přístrojové vybavení metody MeSH
- velikost částic MeSH
- viabilita buněk fyziologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- hodnotící studie MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
Autor popisuje průběh intoxikace tisem červeným u mladého pacienta. Tento poměrně vzácný typ otravy má velmi vysokou mortalitu. Příčinou je významný kardiotoxický účinek taxinů. V závěru sdělení jsou stručně uvedeny dostupné terapeutické možnosti.
The author describes the course of yew intoxication at a young patient. This relatively rare type of poisoning is associated with high mortality rate. It is caused by significant cardiotoxic effect of taxines. In conclusion the author briefly reviews available therapeutic options.
- MeSH
- časná lékařská intervence MeSH
- kardiotoxicita etiologie terapie MeSH
- kardiotoxiny otrava MeSH
- lidé MeSH
- mimotělní membránová oxygenace MeSH
- mladý dospělý MeSH
- multiorgánové selhání * diagnóza etiologie chemicky indukované patofyziologie terapie MeSH
- otrava rostlinami diagnóza etnologie patofyziologie terapie MeSH
- pokus o sebevraždu MeSH
- taxoidy * otrava MeSH
- tis * otrava MeSH
- Check Tag
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- Publikační typ
- kazuistiky MeSH
Composite materials based on a polyamide fabric (aramid) and a polydymethylsiloxane (PDMS) matrix were designed for application in bone surgery. In order to increase the bioactivity, 2, 5, 10, 15, 20, and 25 vol.% of nano/micro hydroxyapatite (HA) and tricalcium phosphate (TCP) were added. We studied the effect of the additives on the biocompatibility of the composite. It appears that nano additives have a more favorable effect on mechanical properties than microparticles. 15 vol.% of nano hydroxyapatite additive is an optimum amount for final application of the composites as substitutes for bone tissue: in this case both the mechanical properties and the biological properties are optimized without distinct changes in the inner structure of the composite.
- MeSH
- apatity MeSH
- dimethylpolysiloxany MeSH
- fosforečnany vápenaté MeSH
- hydroxyapatit MeSH
- kosti a kostní tkáň chirurgie MeSH
- kostní náhrady chemie normy MeSH
- králíci MeSH
- krevní plazma MeSH
- lidé MeSH
- mikroskopie elektronová rastrovací MeSH
- mikrotechnologie MeSH
- nanostruktury MeSH
- nylony MeSH
- osteointegrace fyziologie MeSH
- polymery MeSH
- povrchové vlastnosti MeSH
- pružnost MeSH
- software MeSH
- testování materiálů metody MeSH
- zvířata MeSH
- Check Tag
- králíci MeSH
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
