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

The prognosis of noncutaneous, nonlymphomatous malignancy after heart transplantation: data from the spanish post-heart transplant tumour registry

[Abstract] Introduction. Malignancy is a major complication in the management of solid organ transplant patients. Skin cancers show a better prognosis than other neoplasms, but not all others are equal: Ideally, patient management must take into account the natural history of each type of cancer in relation to the transplanted organs. We sought to determine the prognosis of various groups of noncutaneous nonlymphomatous (NCNL) cancers after heart transplantation (HT). Methods. We retrospectively analyzed the records of the Spanish Post-Heart-Transplant Tumour Registry, which collects data on posttransplant tumors in all patients who have undergone HT in Spain since 1984. Data were included in the study up to December 2008. We considered only the first NCNL post-HT tumors. Results. Of 4359 patients, 375 developed an NCNL cancer. The most frequent were cancers of the lung (n = 97; 25.9%); gastrointestinal tract (n = 52; 13.9%); prostate gland (n = 47; 12.5%; 14.0% of men), bladder (n = 32; 8.5%), liver (n = 14; 3.7%), and pharynx (n = 14; 3.7%), as well as Kaposi's sarcoma (n = 11; 2.9%). The corresponding Kaplan-Meier survival curves differed significantly (P < .0001; log-rank test), with respective survival rates of 47%, 72%, 91%, 73%, 36%, 64%, and 73% at 1 year versus 26%, 62%, 89%, 56%, 21%, 64%, and 73% at 2 years; and 15%, 51%, 77%, 42%, 21%, 64%, and 52% at 5 years post-diagnosis, respectively. Conclusion. Mortality among HT patients with post-HT NCNL solid organ cancers was highest for cancers of the liver or lung (79%–85% at 5 years), and lowest for prostate cancer (23%)

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

Malignancy after heart transplantation: incidence, prognosis and risk factors

[Abstract] The Spanish Post-Heart-Transplant Tumour Registry comprises data on neoplasia following heart transplantation (HT) for all Spanish HT patients (1984–2003). This retrospective analysis of 3393 patients investigated the incidence and prognosis of neoplasia, and the influence of antiviral prophylaxis. About 50% of post-HT neoplasias were cutaneous, and 10% lymphomas. The cumulative incidence of skin cancers and other nonlymphoma cancers increased with age at HT and with time post-HT (from respectively 5.2 and 8.9 per 1000 person-years in the first year to 14.8 and 12.6 after 10 years), and was greater among men than women. None of these trends held for lymphomas. Induction therapy other than with IL2R-blockers generally increased the risk of neoplasia except when acyclovir was administered prophylactically during the first 3 months post-HT; prophylactic acyclovir halved the risk of lymphoma, regardless of other therapies. Institution of MMF during the first 3 months post-HT reduced the incidence of skin cancer independently of the effects of sex, age group, pre-HT smoking, use of tacrolimus in the first 3 months, induction treatment and antiviral treatment. Five-year survival rates after first tumor diagnosis were 74% for skin cancer, 20% for lymphoma and 32% for other tumors

Measurement of the Λ0b→ J/ψΛ angular distribution and the Λ0b polarisation in pp collisions

This paper presents an analysis of the Λ0b→ J/ψΛ angular distribution and the transverse production polarisation of Λ0b baryons in proton-proton collisions at centre-of-mass energies of 7, 8 and 13 TeV. The measurements are performed using data corresponding to an integrated luminosity of 4.9 fb−1, collected with the LHCb experiment. The polarisation is determined in a fiducial region of Λ0b transverse momentum and pseudorapidity of 1 < pT< 20 GeV/c and 2 < η < 5, respectively. The data are consistent with Λ0b baryons being produced unpolarised in this region. The parity-violating asymmetry parameter of the Λ → pπ− decay is also determined from the data and its value is found to be consistent with a recent measurement by the BES III collaboration