The relevance of hydroxyapatite and spongious titanium coatings in fixation of cementless stems. An experimental comparative study in rat femur employing histological and microangiographic techniques.

Pure titanium rods plasma-spray coated with hydroxyapatite (HA) or porous titanium (Ti) of controlled roughness were implanted bilaterally in the distal femur of Sprague-Dawley rats to compare the extent of bone growth on the two types of coating. The relevance of other factors, like mechanical stability and biological adaptation of the bone to the insertion of a foreign body implant, were investigated in femora which were over-reamed (absence of primary fit) or reamed without insertion of the rod. Continuous tetracycline labeling for the first 30 days and for the last 2 weeks in the 90-day group was performed; histological/histometric, fluorescence and microangiographic studies were carried out on serial sections of the implanted and control femora. In the group of stable implants, HA-coated rods showed 90% integration versus 53% with Ti-coated implants (P < 0.001); in over-reamed implants neither surface bone growth nor endosteal fixation occurred, and both types of rods were surrounded by a thick layer of connective tissue. The study documented early adhesion of osteoblasts and direct deposition of bone matrix on the substrate, while on spongious titanium osteogenesis was observed only in proximity to the surface. Remodeling of the reactive, primary bone to mature, lamellar bone took the form of a capsule surrounding the implants and radial bridges connecting the latter to the endosteal surface. The number, height and thickness of these bridges appeared to be the factors determining implant stability, rather than the extent of the bony capsule on the perimeter of the implant. Integration was a function not only of mechanical conditions and surface geometry, but also of the biological response of the whole bone to changes in the vascularization pattern. The reported phenomena can be seen more easily in experimental models involving small rodents because of their fast bone turnover and revascularization, but it is expected that they take place, even at a lower speed, in clinical situations like cementless stems of total hip replacement

Alternative strategies to inhibit tumor vascularization

Endothelial cells present in tumors show different origin, phenotype, and genotype with respect to the normal counterpart. Various mechanisms of intra-tumor vasculogenesis sustain the complexity of tumor vasculature, which can be further modified by signals deriving from the tumor microenvironment. As a result, resistance to anti-VEGF therapy and activation of compensatory pathways remain a challenge in the treatment of cancer patients, revealing the need to explore alternative strategies to the classical anti-angiogenic drugs. In this review, we will describe some alternative strategies to inhibit tumor vascularization, including targeting of antigens and signaling pathways overexpressed by tumor endothelial cells, the development of endothelial vaccinations, and the use of extracellular vesicles. In addition, anti-angiogenic drugs with normalizing effects on tumor vessels will be discussed. Finally, we will present the concept of endothelial demesenchymalization as an alternative approach to restore normal endothelial cell phenotype

The effect of surface roughness on early in vivo plaque colonization on titanium

This study assesses in vivo the surface roughness necessary to reduce plaque colonization on titanium after 24 hours. Three groups of 16 titanium disks were assigned to 3 different polishing groups (A, B, and C). The roughness was evaluated with a laser profilometer and the morphology with a scanning electron microscope (SEM). Eight volunteers were enrolled and two stents were applied in the mandibular posterior region of each. Each stent supported 3 disks, one per group. The volunteers suspended oral hygiene for 24 hours, after which the stents were removed; one was processed for evaluation of the adherent biomass and the other for SEM study. On each specimen a global area of 100 x 125 \u3bcm was examined with SEM. The area was composed of five 20 x 25 \u3bcm randomly selected fields. For each field the density of bacteria and the morphotypes were recorded. The data quoted for the global area are cumulative of those observed in the 20 x 25 \u3bcm fields. Group A had a significantly smoother surface than groups B and C. The adherent microbial biomass determination and SEM evaluation revealed that group A contained less bacteria than the roughest group. The bacterial population was composed of cocci in group A, and of cocci and short and long rods in groups B and C. We conclude that a titanium surface with Ra 64 0.088 \u3bcm and Rz 64 1.027 \u3bcm strongly inhibits accumulation and maturation of plaque at the 24-hour time period and that such smoothness can be achieved in transgingival and healing implant components

Search for lepton-flavour-violating decays of Higgs-like bosons.

A search is presented for a Higgs-like boson with mass in the range 45 to 195 GeV/c2 decaying into a muon and a tau lepton. The dataset consists of proton-proton interactions at a centre-of-mass energy of 8 TeV , collected by the LHCb experiment, corresponding to an integrated luminosity of 2 fb-1 . The tau leptons are reconstructed in both leptonic and hadronic decay channels. An upper limit on the production cross-section multiplied by the branching fraction at 95% confidence level is set and ranges from 22 pb for a boson mass of 45 GeV/c2 to 4 pb for a mass of 195 GeV/c2

Observation of an Excited Bc+ State

Using pp collision data corresponding to an integrated luminosity of 8.5 fb-1 recorded by the LHCb experiment at center-of-mass energies of s=7, 8, and 13 TeV, the observation of an excited Bc+ state in the Bc+π+π- invariant-mass spectrum is reported. The observed peak has a mass of 6841.2±0.6(stat)±0.1(syst)±0.8(Bc+) MeV/c2, where the last uncertainty is due to the limited knowledge of the Bc+ mass. It is consistent with expectations of the Bc∗(2S31)+ state reconstructed without the low-energy photon from the Bc∗(1S31)+→Bc+γ decay following Bc∗(2S31)+→Bc∗(1S31)+π+π-. A second state is seen with a global (local) statistical significance of 2.2σ (3.2σ) and a mass of 6872.1±1.3(stat)±0.1(syst)±0.8(Bc+) MeV/c2, and is consistent with the Bc(2S10)+ state. These mass measurements are the most precise to date

Multilevel factors are associated with immunosuppressant nonadherence in heart transplant recipients: The international BRIGHT study

Factors at the level of family/healthcare worker, organization, and system are neglected in medication nonadherence research in heart transplantation (HTx). The 4-continent, 11-country cross-sectional Building Research Initiative Group: Chronic Illness Management and Adherence in Transplantation (BRIGHT) study used multistaged sampling to examine 36 HTx centers, including 36 HTx directors, 100 clinicians, and 1397 patients. Nonadherence to immunosuppressants\u2014defined as any deviation in taking or timing adherence and/or dose reduction\u2014was assessed using the Basel Assessment of Adherence to Immunosuppressive Medications Scale \ua9 (BAASIS \ua9 ) interview. Guided by the Integrative Model of Behavioral Prediction and Bronfenbrenner's ecological model, we analyzed factors at these multiple levels using sequential logistic regression analysis (6 blocks). The nonadherence prevalence was 34.1%. Six multilevel factors were associated independently (either positively or negatively) with nonadherence: patient level: barriers to taking immunosuppressants (odds ratio [OR]: 11.48); smoking (OR: 2.19); family/healthcare provider level: frequency of having someone to help patients read health-related materials (OR: 0.85); organization level: clinicians reporting nonadherent patients were targeted with adherence interventions (OR: 0.66); pickup of medications at physician's office (OR: 2.31); and policy level: monthly out-of-pocket costs for medication (OR: 1.16). Factors associated with nonadherence are evident at multiple levels. Improving medication nonadherence requires addressing not only the patient, but also family/healthcare provider, organization, and policy levels