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Osteoporosis is a skeletal disorder characterized by low bone mass and microarchitectural deterioration of bone tissue with consequent increase in bone fragility and fracture risk. Bone mineral density (BMD), the major determinant of osteoporotic fracture risk, has a particular genetic background. Vitamin D receptor (VDR) is implicated in the regulation of bone mineral density. The present study evaluates the association between Vitamin D receptor gene polymorphisms Fok I (rs2228570), Cdx-2 (rs11568820), bone mineral density and fracture risk in Slovak postmenopausal women. A total of 403 unrelated Slovak postmenopausal women aged 43-86 years were genotyped using TaqMan®SNP Genotyping Assays. Lumbar spine, femoral neck and total hip BMD/T-score were detected by dual energy X-ray absorptiometry (DEXA). We found the Fok I and Cdx-2 polymorphism in the VDR gene to be associated with osteoporotic fractures (non-vertebral fractures: Fok I p = 0.001; Cdx-2 p = 0.0000; all fractures: Fok I p = 0.0001; Cdx-2 p = 0.0000) (Fok I: OR = 0.50, 95% CI = 0.35-0.71; Cdx-2: OR = 0.25, 95% CI = 0.17-0.37). The present data suggest that VDR gene Fok I and Cdx-2 polymorphisms contribute to the determination of BMD in Slovak postmenopausal women and can probably be used with other genetic markers together to identify individuals at high risk of osteoporosis.

Osteoporosis is a skeletal disorder characterized by low bone mass and microarchitectural deterioration of bone tissue with consequent increase in bone fragility and fracture risk. Bone mineral density (BMD), the major determinant of osteoporotic fracture risk, has a particular genetic background. Vitamin D receptor (VDR) is implicated in the regulation of bone mineral density. The present study evaluates the association between Vitamin D receptor gene polymorphisms

Several bone cements were prepared in two ways of mixing (manual and vacuum bowl). Wear behavior, friction coefficient were studied by ball on disc method. Nano-hardness and Young`s modulus was studied by instrumented indentation. Obtained results were summarized by taking into account their way preparation, antibiotics content and testing conditions. There was found no significant time dependence of saline acting on Young`s modulus and nano-hardness values. Friction coefficient in saline was less than half in compare to dry sliding conditions

Various bone cements with different compositions were prepared in several model configurations which differed in volume (i.e. setting temperature profile) and mode of mixing (manual and vacuum bowl). Local mechanical properties (nanohardness, elasticity modulus) of all experimental states were measured by nanoindentation technique and compared. Role of the preparation route as well as influence of composition, particularly of presence of antibiotics, on the measured properties was investigated.

Članak obuhvaća studiju uporabe ultrazvučnog pulzirajućeg mlaza vode odabranih svojstava za razgradnju veze ostvarene pomoću koštanog cementa između cementiranog bedrenog drška i trabekularnog koštanog tkiva, kao potencijalne tehnike za revizijsku artroplastiku. Šest tipova komercijalnog koštanog cementa baziranog na polimetil metakrilatu rabljeni su za ovo istraživanje. Cementi su miješani uz pomoć DePuy - SmartMix® CTS / vakumske zdjele za miješanje. Mehanička svojstva ojačanog koštanog cementa određena su nanoindentacijom. Uzorci koštanog cementa su razgrađeni primjenom tehnologije pulzirajućeg mlaza vode. Tlak vode se mijenjao između 8 i 20 MPa. Kružna mlaznica s promjerom otvora od 0,7 mm je rabljena za rezanje mlazom vode. Odstojanje od ciljanog materijala bilo je 2 mm, a poprečna brzina iznosila je 1 mm/s. Volumen odstranjenog materijala i dubina kreiranih tragova mjereni su pomoću MicroProf FRT optičkog profilometra. Rezultati pozitivno podupiru pretpostavku da pulzirajući mlaz vode ima potencijal biti odgovarajuća tehnika za brzu i sigurnu razgradnju koštanog cementa pri revizijskoj artroplastici., The paper deals with the study of using the selective property of ultrasonic pulsating water jet for the disintegration of the interface created by bone cement between cemented femoral stem and trabecular bone tissue as a potential technique for revision arthroplasty. Six types of commercial bone cements based on Polymethyl Methacrylate were used for investigation. The cements were mixed using the DePuy - SmartMix® CTS / vacuum mixing bowl. Mechanical properties of hardened bone cements were determined by nanoindentation. The bone cement samples were disintegrated using the pulsating water jet technology. The water pressure varied between 8÷20 MPa. A circular nozzle with an orifice diameter of 0,7 mm was used for water jetting. The stand-off distance from the target material was 2 mm and the traverse speed 1 mm/s. The volume of material removal and depth of created traces were measured by MicroProf FRT optical profilometer. The results positively support an assumption that pulsating water jet has a potential to be a suitable technique for the quick and safe disintegration of bone cement during revision arthroplasty.

Osteoporosis is a common disease that is characterized by low bone mineral density (BMD), deterioration in bone microarchitecture, and increased fracture risk. Due to its important role in bone biology, the TNFRSF11B gene, coding for OPG, has been considered as a candidate gene for osteoporosis. In this study, single nucleotide polymorphisms (SNPs) A163G, T245G, and G1181C (rs3102735, rs3134069, and rs2073618, respectively) within the TNFRSF11B gene were studied for association with BMD and fracture incidence in a cohort of 327 postmenopausal Slovak women. Genomic DNA was extracted and purified from peripheral blood leukocytes by the commercial kit JetQuick (Genomed GmbH, Germany) using a standard protocol. Genotyping was performed using the Custom TaqMan® SNP Genotyping Assays. The lumbar L1-L4 spine BMD (g/cm(2)) and T-score in the subgroup of Slovak postmenopausal women with osteoporotic fractures were significantly lower than those in the subgroup of women without fracture (p = 0.0025; p = 0.0009). We identified the T245G (rs3134069) polymorphism in the TNFRSF11B gene associated with osteoporotic fractures (vertebral fractures: p = 0.0320; non-vertebral fractures: p = 0.0005; all fractures: 0.0000). The polymorphism T245G (rs3134069) in the TNFRSF11B gene could be used together with other genetic markers to identify individuals at high risk of osteoporotic fractures. The results from the present study provided more evidence to reveal the role of TNFRSF11B gene polymorphisms in BMD and the risk of osteoporotic fractures.

Improving of bone cements properties is possible by research of variables influencing exothermal behaviour and mechanical properties. Paper deals with exothermal behaviour experimental evaluation of bone cements used for medical purposes. Specimens were prepared by a conventional manual mixing technique. The work addresses primary risk factor associated with application of bone cement to femoral canal. Different size samples of bone cement has been created with diameter d = 2; 5;12,5 mm fixed in dentacryl. As an experimental material, Palacos R+G high viscosity, radiopaque bone cement containing Gentamicin and Radiopaque bone cement Antibiotic Simplex with Tobramycin, was used. Thermal effect during exothermic polymerisation was measured with period 1 minute. Evaluated factors were mass and thickness of bone cement. Significant influence of bone cement mass on temperature has been found.

Članak se bavi proučavanjem uporabe kontinuiranog vodenog mlaza i nadzvučnog pulsirajućeg mlaza vode za dezintegraciju koštanog cementa. Koštani cement Pallacos R+G (ručno miješan) dezintegriran je ex-vivo. Mehanička svojstva koštanog cementa određena su pomoću nano-utiskivanja. Faktori u procjeni bili su tlakovi (40, 80, 120) MPa i poprečna brzina kontinuiranog mlaza vode, tlak (8, 10, 12, 14, 16, 20) MPa i tip prigušnice (ravna, kružna) za nadzvučni pulsirajući mlaz vode. Dubina prodiranja h (mm) mjerena je bezkontaktnim optičkim profilometerom MicroProf FRT. Rezultati predstavljaju prvi korak ka izvedivosti uporabe učinkovite tehnike vodenog mlaza tijekom reimplantacije cementiranih endoproteza, za uklanjanje koštanog cementa iz bedrenog kanala bez topline i mehaničkog oštećenja okolnog tkiva., The paper deals with the study of using continuous water jet and ultrasonic pulsating water jet for bone cement disintegration. Bone-cement Pallacos R+G (manually mixed) was disintegrated ex-vivo. Mechanical properties of the bone cement were determined by nano-indentation. Factors employed in evaluation were pressure (40, 80, 120) MPa and traverse speed for continuous water jet, pressure (8, 10, 12, 14, 16, 20) MPa and orifice type (flat, circular) for ultrasonic pulsating water jet. Depth penetration h (mm) was measured by non-contact optical profilometer MicroProf FRT. Results represent the first step towards feasibility of using effective water jet technique during reimplantation of cemented endoprosthesis, for bone cement removal from femoral canal without heat and mechanical damage of surrounding tissue.