Bionate biocompatibility: in vivo study in rabbits

Response to foreign materials includes local tissue reaction, osteolysis, implant loosening, and migration to lymph nodes and organs. Bionate 80A human explants show minor wear and slight local tissue reaction, but we do not know the response at the spinal cord, nerve roots, lymph nodes, or distant organs. This study aims to figure out reactions against Bionate 80A when implanted at the spinal epidural space of 24 20-week-old New Zealand white rabbits. In one group of 12 rabbits, we implanted Bionate 80A on the spinal epidural space, and another group of 12 rabbits was used as the control group. We studied tissues, organs, and tissue damage markers on blood biochemistry, urine tests, and necropsy. The animals' clinical parameters and weight showed no statistically significant differences. At 3 months, the basophils increased slightly in the implant group, platelets decreased in all, and at 6 months, implanted animals showed slight eosinophilia, but none of these changes was statistically significant. External, organ, and spinal tissue examination showed neither toxic reaction, inflammatory changes, or noticeable differences between groups or survival periods. Under microscopic examination, the Bionate 80A particles induced a chronic granulomatous response always outside the dura mater, with giant multinucleated cells holding phagocytized particles and no particle migration to lymph nodes or organs. Thus, it was concluded that Bionate particles, when implanted in the rabbit lumbar epidural space, do not generate a significant reaction limited to the surrounding soft tissues with giant multinucleated cells. In addition, the particles did not cross the dura mater or migrate to lymph nodes or organs

Barbed Dental Ti6Al4V Alloy Screw : Design and Bench Testing

Background context. Dental implants are designed to replace a missing tooth. Implant stability is vital to achieving osseointegration and successful implantation. Although there are many implants available on the market, there is room for improvement. Purpose. We describe a new dental implant with improved primary stability features. Study design. Lab bench test studies. Methods. We evaluated the new implant using static and flexion-compression fatigue tests with compression loads, 35 Ncm tightening torque, displacement control, 0.01 mm/s actuator movement speed, and 9-10 Hz load application frequency, obtaining a cyclic load diagram. We applied variable cyclic loadings of predetermined amplitude and recorded the number of cycles until failure. The test ended with implant failure (breakage or permanent deformation) or reaching five million cycles for each load. Results. Mean stiffness was 1151.13 ± 133.62 SD N/mm, mean elastic limit force 463.94 ± 75.03 SD N, and displacement 0.52 ± 0.04 SD mm, at failure force 663.21 ± 54.23 SD N and displacement 1.56 ± 0.18 SD mm, fatigue load limit 132.6 ± 10.4 N, and maximum bending moment 729.3 ± 69.43 mm/N. Conclusions. The implant fatigue limit is satisfactory for incisor and canine teeth and between the values for premolars and molars for healthy patients. The system exceeds five million cycles when subjected to a 132.60 N load, ensuring long-lasting life against loads below the fatigue limit

Bionate Lumbar Disc Nucleus Prosthesis : Biomechanical Studies in Cadaveric Human Spines

Design: cadaveric spine nucleus replacement study. Objective: determining Bionate 80A nucleus replacement biomechanics in cadaveric spines. Methods: in cold preserved spines, with ligaments and discs intact, and no muscles, L3-L4, L4-L5, and L5-S1 nucleus implantation was done. Differences between customized and overdimensioned implants were compared. Flexion, extension, lateral bending, and torsion were measured in the intact spine, nucleotomy, and nucleus implantation specimens. Increasing load or bending moment was applied four times at 2, 4, 6, and 8 Nm, twice in increasing mode and twice in decreasing mode. Spine motion was recorded using stereophotogrammetry. Expulsion tests: cyclic compression of 50-550 N for 50,000 cycles, increasing the load until there was extreme flexion, implant extrusion, or anatomical structure collapse. Subsidence tests were done by increasing the compression to 6000 N load. Results: nucleotomy increased the disc mobility, which remained unchanged for the adjacent upper level but increased for the lower adjacent one, particularly in lateral bending and torsion. Nucleus implantation, compared to nucleotomy, reduced disc mobility except in flexion-extension and torsion, but intact mobility was no longer recovered, with no effect on upper or lower adjacent segments. The overdimensioned implant, compared to the customized implant, provided equal or sometimes higher mobility. Lamina, facet joint, and annulus removal during nucleotomy caused more damaged than that restored by nucleus implantation. No implant extrusion was observed under compression loads of 925-1068 N as anatomical structures collapsed before. No subsidence or vertebral body fractures were observed under compression loads of 6697.8-6812.3 N. Conclusions: nucleotomized disc and L1-S1 mobility increased moderately after cadaveric spine nucleus implantation compared to the intact status, partly due to operative anatomical damage. Our implant had shallow expulsion and subsidence risks

Nucleus disc replacement : designs and material selection FEA analysis

Study design. Material selection, implant design and Finite Element Analysis (FEA) studies. Background. Nucleus disc replacements, implanted since 1960, have undergone continuous evolution in materials and designs, but subsidence, extrusion, and in vivo degradation limit widespread use. Aim: To create a new nucleus disc replacement that avoids the abovementioned drawbacks. Material and Methods. We created eighteen designs with varied materials and analyzed them with FEA in compression and shear tests in a lumbar spine model programmed in Ansys Parametric Design Language. Results. Bionate® 80A had the closest mechanical characteristics to the intact disc nucleus. Monobloc designs bore the physiological stresses correctly but suffered significant deformations with permanent damage during surgical insertion through the annulus opening. In addition, sandwich designs were too rigid and had an unreliable curing process. Therefore, we chose an oval doughnut-like 5 mm wall monobloc Bionate® 80A nucleus replacement. It minimized implant stress in loading, distributed the loads uniformly, and tolerated the lateral compression during implantation. Conclusions. Out of the eighteen designs we analyzed with FEA, we found that the monobloc oval doughnut-like Bionate 80A nucleus replacement reproduced best the biomechanics of the natural disc nucleus and had the lowest subsidence risk as it transmits the load to the ring apophysis. Furthermore, due to its elasticity implanting it through the average annulotomy required to perform a lumbar microdiscectomy should be possible

ADDISC lumbar disc prosthesis : Analytical and FEA testing of novel implants

The intact intervertebral disc is a six-freedom degree elastic deformation structure with shock absorption. 'Ball-and-socket' TDR do not reproduce these properties inducing zygapophyseal joint overload. Elastomeric TDRs reproduce better normal disc kinematics, but repeated core deformation causes its degeneration. We aimed to create a new TDR (ADDISC) reproducing healthy disc features. We designed TDR, analyzed (Finite Element Analysis), and measured every 500,000 cycles for 10 million cycles of the flexion-extension, lateral bending, and axial rotation cyclic compression bench-testing. In the inlay case, we weighted it and measured its deformation. ADDISC has two semi-spherical articular surfaces, one rotation centre for flexion, another for extension, the third for lateral bending, and a polycarbonate urethane inlay providing shock absorption. The first contact is between PCU and metal surfaces. There is no metal-metal contact up to 2000 N, and CoCr28Mo6 absorbs the load. After 10 million cycles at 1.2-2.0 kN loads, wear 140.96 mg (35.50 mm3), but no implant failures. Our TDR has a physiological motion range due to its articular surfaces' shape and the PCU inlay bumpers, minimizing the facet joint overload. ADDISC mimics healthy disc biomechanics and Instantaneous Rotation Center, absorbs shock, reduces wear, and has excellent long-term endurance

Dietary niche overlap and resource partitioning among six steppe passerines of Central Spain using DNA metabarcoding

Trophic niche partitioning is a mechanism that facilitates the coexistence of ecologically similar species by sharing their resource use. However, detailed information of the trophic niche in insectivorous birds is usually limited by the lack of accurate identification of consumed food resources. The use of DNA metabarcoding has proved useful for molecular identification of the taxa present in bird faecal samples. Here, we used this molecular technique to study the diets of six steppe passerine species distributed in two Special Protection Areas in central Spain, and to characterize the dietary niche overlap and the prey composition differences between bird species. In total, we distinguished 112 diet items, covering 39 arthropod families of 13 orders. Although significant dietary differences existed in prey species composition, our results indicated a 74% overlap in steppe bird dietary niche, mostly due to high consumption of abundant arthropod prey such as beetles, grasshoppers and spiders in the breeding season by all bird species. The lowest overlap was found for the dietary niches of the Greater Short-toed Lark Calandrella brachydactyla and Dupont's Lark Chersophilus duponti, a scarce and threatened species, which appeared to be the species with the most distinct dietary niche within the community. Our results make a significant contribution to the knowledge of shrub-steppe bird diets and their trophic interactions, indicating that some extent of interspecific resource partitioning occurs in the study area, notably between Dupont's Lark and the Greater Short-toed Lark. Our study demonstrates the value of DNA metabarcoding in the assessment of passerine diets and provides useful ecological results for the design of biodiversity conservation programmes in the increasingly scarce and threatened steppe habitatsThis study was supported by the European Commission LIFE Ricot ı (LIFE15-NAT-ES-000802) and LIFE Connect Ricot ı (LIFE20-NAT-ES-000133) projects, and the BBVA Foundation Dron Ricot ı project. This is a contribution to the Excellence Network Remedinal 3CM (S2013/MAE2719). Lu ıs P. da Silva and Vanessa A. Mata were funded by Fundac ~ao para a Ci^encia e Tecnologia (FCT) through the research contract CEECIND/02064/ 2017 and 2020.02547.CEECIND, respectivel

Infección periprotésica aguda de rodilla por fusobacterium nucleatum. Revisión de la literatura a propósito de un caso.

Fusobacterium Nucleatum is an anaerobic commensal microorganism present in the oral cavity and some mucous membranes with great capacity to form biofilm. In the literature, only one case of acute periprosthetic infection of the knee by Fusobacterium Nucleatum has been reported, providing the second case. A 72-year-old man presented with an acute periprosthetic infection by fusobacterium nucleatum after a second time of a prosthetic knee replacement. Debridement and spacer changes were performed up to 4 times, associating parenteral antibiotic treatment. After ensuring the absence of infection, a modular revision knee prosthesis with stems was placed, with a satisfactory evolution after two years. Currently he has preserved ambulation, joint balance of 0º-50º and is free of infection. Fusobacterium Nucleatum infection is very rare, but aggressive and difficult to resolve, recommending two-stage replacement in acute infection and adequate antibiotic treatment to offer curative treatment

Modulating the immune response to SARS-CoV-2 by different nanocarriers delivering an mRNA expressing trimeric RBD of the spike protein: COVARNA Consortium

15 Pág.Vaccines based on mRNA technology have revolutionized the field. In fact, lipid nanoparticles (LNP) formulated with mRNA are the preferential vaccine platform used in the fight against SARS-CoV-2 infection, with wider application against other diseases. The high demand and property right protection of the most potent cationic/ionizable lipids used for LNP formulation of COVID-19 mRNA vaccines have promoted the design of alternative nanocarriers for nucleic acid delivery. In this study we have evaluated the immunogenicity and efficacy of different rationally designed lipid and polymeric-based nanoparticle prototypes against SARS-CoV-2 infection. An mRNA coding for a trimeric soluble form of the receptor binding domain (RBD) of the spike (S) protein from SARS-CoV-2 was encapsulated using different components to form nanoemulsions (NE), nanocapsules (NC) and lipid nanoparticles (LNP). The toxicity and biological activity of these prototypes were evaluated in cultured cells after transfection and in mice following homologous prime/boost immunization. Our findings reveal good levels of RBD protein expression with most of the formulations. In C57BL/6 mice immunized intramuscularly with two doses of formulated RBD-mRNA, the modified lipid nanoparticle (mLNP) and the classical lipid nanoparticle (LNP-1) were the most effective delivery nanocarriers at inducing binding and neutralizing antibodies against SARS-CoV-2. Both prototypes fully protected susceptible K18-hACE2 transgenic mice from morbidity and mortality following a SARS-CoV-2 challenge. These results highlight that modulation of mRNAs immunogenicity can be achieved by using alternative nanocarriers and support further assessment of mLNP and LNP-1 prototypes as delivery vehicles for mRNA vaccines.This investigation was supported by Preclinical development of innovative mRNA/MVA vaccines against SARS-CoV-2, COVARNA Consortium, Instituto de Salud Carlos III and Generalitat de Catalunya, La CaixaImpulse grant CF01-00008 and Ferrovial and MAPFRE donations (to ME). We also acknowledge financial support from the Spanish State Research Agency, AEI/10.13039/501100011033, through the “Severo Ochoa” Programme for Centers of Excellence in R&D (SEV-2013-0347, SEV-2017-0712). This study was partially supported by grants from the Instituto de Salud Carlos III (grants: COV20/00214; ICI20/00067), the Fondo Europeo para el Desarrollo Regional (FEDER) and the CERCA Programme/Generalitat de Catalunya SGR 615 and SGR 653.Peer reviewe

Author Correction: Modulating the immune response to SARS-CoV-2 by different nanocarriers delivering an mRNA expressing trimeric RBD of the spike protein: COVARNA Consortium

Correction to: npj Vaccines (2024) 9:53; https://doi.org/10.1038/s41541-024-00838-8, published online 06 March 2024 http://hdl.handle.net/10261/353891 1 Pág.In this article, the author name Núria López-Bigas was incorrectly written as Nuria López-Vigas. The original article has been corrected.Peer reviewe