Spontaneous osteoclastogenesis: Hypothesis for gender-unrelated osteoporosis screening and diagnosis.

Women are at greater risk of developing osteoporosis (OP). However, in the past few years it has become more widely recognized that OP is a significant problem also in men although OP is frequently under-diagnosed and, consequently, under treated in men. Most guidelines, screening and fracture risk evaluation methods as well as pharmacologic agents have been developed for women and then adapted to men. Bone Mineral Density (BMD) measurement by Dual X-ray Absorptiometry (DEXA) is reported as T score and the capability of DEXA to diagnose OP and predict fracture risk is still debated. In addition, the use of female T score references for the diagnosis of OP in men is incorrect for the following reasons: 1) DXA definition was developed just for Caucasian women, 2) men and women display structural differences in terms of bone growth, catabolism and size; 3) aging men have more periosteal apposition, less cortical porosity and endocortical resorption than aging women; and 4) T scores results, both in man and in women, can be affected by the presence of co-morbidities and it is known that in men OP is often secondary. From a biological point of view, OP is mainly due to increased osteoclastic activity leading to an imbalance in bone remodeling that favors resorption. However, some evidence suggests a more complex identity for osteoclasts (OCs) over and above their simple role of 'bone eaters'. In our laboratory, we observed spontaneous OCs formation in vitro in peripheral blood mononuclear cells (PBMC) from OP patients (n.12 female patients and n.6 male patients; DXA T score-2.5 or less). Some researchers demonstrated OCs gender differences in bone resorption activity of female-derived versus male-derived OCs. Indeed, further data from our laboratory also showed gender differences in number of spontaneously differentiated OCs and differentiation time. Therefore, we hypothesized that it would be possible to perform OP screening and diagnosis observing and measuring PBMCs different ability to differentiate spontaneously into OCs in male and female patients. If this hypothesis will be confirmed, it will result in an effective and efficient strategy for OP screening, diagnosis, monitoring and fracture prevention, targeting health service resources on selected patients. However, our hypothesis must be tested in a properly designed clinical trial and several key issues still need to be addressed.

Three-dimensional cellular distribution in polymeric scaffolds for bone regeneration: a microCT analysis compared to SEM, CLSM and DNA content.

In orthopaedic surgery the tissues damaged by injury or disease could be replaced using constructs based on biocompatible materials, cells and growth factors. Scaffold design, porosity and early colonization are key components for the implant success. From biological point of view, attention may be also given to the number, type and size of seeded cells, as well as the seeding technique and cell morphological and volumetric alterations. This paper describes the use of the microCT approach (to date used principally for mineralized matrix quantification) to observe construct colonization in terms of cell localization, and make a direct comparison of the microtomographic sections with scanning electron microscopy images and confocal laser scanning microscope analysis. Briefly, polycaprolactone scaffolds were seeded at different cell densities with MG63 osteoblastic-like cells. Two different endpoints, 1 and 2 weeks, were selected for the three-dimensional colonization and proliferation analysis of the cells. By observing all images obtained, in addition to a more extensive distribution of cells on scaffolds surfaces than in the deeper layers, cell volume increased at 2 weeks compared to 1 week after seeding. Combining the cell number quantification by deoxyribonucleic acid analysis and the single cell volume changes by confocal laser scanning microscope, we validated the microCT segmentation method by finding no statistical differences in the evaluation of the cell volume fraction of the scaffold. Furthermore, the morphological results of this study suggest that an effective scaffold colonization requires a precise balance between different factors, such as number, type and size of seeded cells in addition to scaffold porosity.

Injectable calcium-phosphate-based composites for skeletal bone treatments.

Alpha-tricalcium-phosphate-based bone cements hydrolyze and set, producing calcium-deficient hydroxyapatite. They can result in an effective solution for bone defect reconstruction due to their biocompatibility, bioactivity and adaptation to shape and bone defect sizes, together with an excellent contact between bone and graft. Moreover, the integration of hydrogel phase based on poly(vinyl alcohol) (PVA) to H-cem-composed of α-tricalcium phosphate (98% wt) and hydroxyapatite (2% wt)-allows improving the mechanical and biological properties of the cement. The aim of this work was to evaluate the influence of the PVA on relevant properties for the final use of the injectable bone substitute, such as setting, hardening, injectability and in vivo behaviour. It was shown that by using PVA it is possible to modulate the setting and hardening properties: large increase in injectability time (1 h) in relation with the plain cement (few minutes) was achieved. Moreover, in vivo tests confirmed the ability of the composite to enhance bone healing in trabecular tissue. Histological results from critical size defects produced in rabbit distal femoral condyles showed after 12 weeks implantation a greater deposition of new tissue on bone-composite interfaces in comparison to bone-cement interfaces. The quality of bone growth was confirmed through histomorphometric and microhardness analysis. Bone formation in the composite implantation sites was significantly higher than in H-cem implants at both times of evaluation.

Targeting the phosphatidylinositol 3-kinase/Akt/mammalian target of rapamycin signaling network in cancer stem cells.

Cancer stem cells (CSCs) comprise a subset of hierarchically organized, rare cancer cells with the ability to initiate cancer in xenografts of genetically modified murine models. CSCs are thought to be responsible for tumor onset, self-renewal/maintenance, mutation accumulation, and metastasis. The existence of CSCs could explain the high frequency of neoplasia relapse and resistance to all of currently available therapies, including chemotherapy. The phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) signaling pathway is a key regulator of physiological cell processes which include proliferation, differentiation, apoptosis, motility, metabolism, and autophagy. Nevertheless, aberrantly upregulated PI3K/Akt/mTOR signaling characterizes many types of cancers where it negatively influences prognosis. Several lines of evidence indicate that this signaling system plays a key role also in CSC biology. Of note, CSCs are more sensitive to pathway inhibition with small molecules when compared to healthy stem cells. This observation provides the proof-of-principle that functional differences in signaling transduction pathways between CSCs and healthy stem cells can be identified. Here, we review the evidence which links the signals deriving from the PI3K/Akt/mTOR network with CSC biology, both in hematological and solid tumors. We then highlight how therapeutic targeting of PI3K/Akt/mTOR signaling with small molecule inhibitors could improve cancer patient outcome, by eliminating CSCs.

Thyroid hormones and the cardiovascular system: pathophysiology and interventions.

Thyroid dysfunction, however mild, can significantly affect the cardiovascular (CV) system. The effects of thyroid hormones may be viewed as genomic and non-genomic, with the former occurring over a longer time scale and both affecting structural and functional proteins in CV tissue. As the interplay between thyroid function and the CV system becomes elucidated, particularly in the context of a system biology approach, the heart failure phenotype is better understood. Symptomatology is related to disturbance in inotropic and chronotropic function. Moreover, biochemical changes reflected by thyroid function testing with the non-thyroidal illness syndrome can prognosticate and guide therapy in heart failure. In addition, empiric treatment with thyroid hormone analogues or T3 represent emergent and highly controversial interventions.

Effect of Mg(2+), Sr(2+), and Mn(2+) on the chemico-physical and in vitro biological properties of calcium phosphate biomimetic coatings.

We previously developed a calcium phosphate (CaP) calcifying solution that allows to deposit a uniform layer of nanocrystalline apatite on metallic implants in a few hours. In this work we modified the composition of the CaP solution by addition of Sr(2+), Mg(2+), and Mn(2+), in order to improve the biological performance of the implants. The results of the investigation performed on the coatings, as well as on the powders precipitated in the absence of the substrates, indicate that both Sr(2+) and Mg(2+) reduce the extent of precipitation, although they are quantitatively incorporated into the nanocrystalline apatitic phase. The inhibitory effect on deposition is much more evident for Mn(2+), which completely hinders the precipitation of apatite and yields just a small amount of amorphous phosphate relatively rich in manganese content. Human osteoblast-like MG-63 cells cultured on the different materials show that the Mg(2+) and Sr(2+) apatitic coatings promote proliferation and expression of collagen type I, with respect to bare Ti and to the thin layer of amorphous phosphate obtained in the presence of Mn(2+). However, the relatively high content of Mn(2+) in the phosphate has a remarkable beneficial effect on osteocalcin production, which is even greater than that observed for Sr(2+).

Porous composite scaffolds based on gelatin and partially hydrolyzed alpha-tricalcium phosphate.

Porous composite scaffolds of varying compositions were prepared by freeze-drying gelatin foams containing increasing amounts of alpha-tricalcium phosphate (alpha-TCP), up to about 40 wt.%. Due to the presence of gelatin, a partial hydrolysis of alpha-TCP into octacalcium phosphate (OCP) occurs during foaming. As a consequence, the scaffolds contain both alpha-TCP and OCP, in relative amounts of about 74% and 26%, respectively, independent of the initial composition. In physiological conditions the inorganic component of the scaffolds undergoes a further hydrolysis as shown by the finding that after immersion in phosphate-buffered saline at 37 degrees C for 1 week the scaffolds contain poorly crystalline hydroxyapatite together with OCP. The scaffolds display a porous interconnected microstructure. The mean dimensions of the pores decrease from about 350 to about 170 microm as the inorganic phase content increases. Simultaneously, the mean values of the compression strength and Young's modulus increase. Stabilization of the scaffolds was obtained by using a natural, non-toxic, crosslinking agent, genipin, which significantly improves their mechanical properties.

Comparative in vivo evaluation of porous and dense duplex titanium and hydroxyapatite coating with high roughnesses in different implantation environments.

Ti (PG60) and Ti plus HA (HPG60) dense coatings with ultrahigh roughness (Ra: 74 +/- 8 microm and 53 +/- 18 microm, respectively) were compared to high Ti (Ti60) and Ti plus HA (HT60) high roughened porous coatings (Ra: 40 +/- 7 microm and 36 +/- 3 microm, respectively). Surfaces were implanted in cortical and trabecular bone of young adult (YOUNG), aged (AGED) and estrogen-deficient sheep (OVX) and analyzed by means of histology, histomorphometry and push-out tests 3 months after implantation. A significantly lower value in affinity index (AI) of PG60 when compared to TI60 (p < 0.01) was observed in cortical bone. In trabecular bone, lower values in AI were found in TI60 and PG60 when compared to their HA-coated surfaces (p < 0.0005). Bone ingrowth (BI) of TI60 and PG60 was significantly lower than that of the HA-coated surfaces in trabecular bone (p < 0.05). Significantly lower values in BI in OVX sheep in comparison to YOUNG sheep in both cortical and trabecular bone were observed (p < 0.05). Data showed that high roughness and Ti and HA-coated surfaces are suitable for aged and osteoporotic patients. HA coatings represent the most successful strategy in trabecular bone.

Interaction of Sr-doped hydroxyapatite nanocrystals with osteoclast and osteoblast-like cells.

This article reports the effect of strontium incorporation into hydroxyapatite nanocrystals on bone cells response. Hydroxyapatite nanocrystals were synthesized at strontium contents of 0, 1, 3, 7 atom %. Strontium incorporation for calcium is confirmed by the linear increase of the unit cell parameters of hydroxyapatite, in agreement with the different ionic radii of the two ions. Moreover, strontium substitution slightly affects hydroxyapatite structural order and the shape of the nanocrystals. Osteoblast-like MG63 cells cultured on the nanocrystals display good proliferation and increased values of the differentiation parameters. In particular, when cultured on samples with Sr concentration in the range 3-7 atom %, osteoblasts display increased values of ALP activity, collagen type I, and osteocalcin production. Moreover, the osteoclast number on all the Sr-doped samples is significantly smaller than on hydroxyapatite, and it decreases on increasing strontium content. The data indicate that strontium stimulates osteoblast activity and exerts its inhibitory effect on osteoclast proliferation even when incorporated into hydroxyapatite.

OP-1 application in bone allograft integration: preliminary results in sheep experimental surgery.

UNLABELLED: Massive bone allografts are frequently used in orthopaedic reconstructive surgery. However the failure rate at long term follow-up is around 25%. AIM: Stimulation of allograft incorporation. MATERIALS AND METHODS: In order to stimulate bone remodeling of an allograft we applied recombinant human osteogenic protein-1 (rh-OP-1, also know as bone morphogenetic protein-7, BMP-7) to a long bone critical size defect sheep model. In nine sheep we created a 3 cm osteoperiosteal metatarsal defect replaced with a structural allograft alone (control group, 4 animals), or an allograft added with rh-BMP-7 (BMP group, 5 animals). Radiographic, mechanical, histological and histomorphometric analysis were performed. RESULTS: X-rays in the BMP group showed a better and faster callus formation, compared to the control group within the first 8 weeks after surgery. After 16 weeks there was a higher evidence of bone remodeling in the BMP group. Radiographic healing at junction sites was more evident in the BMP group at 4, 8 and 16 weeks. Mechanical testing on screw extraction showed no statistical differences between the two groups and histomorphometry showed no difference in terms of newly formed bone inside the allograft as well. The resorption rate of the graft was higher in the BMP group in comparison to the control group. The penetration of newly formed vessels was significantly higher in the BMP group. CONCLUSIONS: These findings indicate that BMP-7 added to a structural bone allograft inducing early remodeling of the graft through stimulation of neo-angiogenesis and osteoclastic activity, without negative effects in mechanical strength and clinical outcome.

Setting properties and in vitro bioactivity of strontium-enriched gelatin-calcium phosphate bone cements.

Strontium is known to reduce bone resorption and stimulate bone formation. We have investigated the effect of strontium on the setting properties and in vitro bioactivity of a biomimetic gelatin-calcium phosphate bone cement. Gelatin-alpha-TCP powders, with a gelatin content of 15 wt %, were prepared by grinding and sieving the solid compounds obtained by casting gelatin aqueous solutions containing alpha-TCP. 5 wt % of CaHPO(4).2H(2)O were added to the cement powders before mixing with the liquid phase, with a L/P ratio of 0.3 mL/g. Strontium was added as SrCl(2).6H(2)O in different amounts up to 5 atom %. X-ray diffraction analysis, mechanical tests, and SEM investigations were carried out on the cements after different times of soaking in physiological solution. The presence of strontium affects both the initial and the final setting times of the cements, which increase with the ion content. The microstructural modifications observed in the SEM micrographs of the fractured surfaces are in agreement with the increase of the total porosity, and with the slight reduction of the compressive strength of the aged cements, on increasing strontium content. The rate of transformation of alpha-TCP into calcium deficient hydroxyapatite increases on increasing strontium content. SEM reveals that MG63 osteoblasts grown on the cements show a normal morphology and biological tests demonstrate very good rate of proliferation and viability in every experimental time. In particular, strontium stimulates Alkaline Phosphatase activity, Collagen type I, osteocalcin, and osteoprotegerin expression.

In vitro and in vivo behaviour of biodegradable and injectable PLA/PGA copolymers related to different matrices.

This study comparatively investigates the in vitro and in vivo behavior of injectable polymeric materials for the treatment of bone defects. The tested materials were three injectable and biodegradable PLA/PGA 50/50 copolymers dispersed in different matrices: Fisograft-gel (GEL) was dispersed in an aqueous matrix of poly-ethyl-glycole (PEG); Slurry2 (SL2) was dispersed in an aqueous matrix of PEG and dextran; and Slurry6 (SL6) was dispersed in a 3% agarose matrix. The biological characterization of these materials was studied by in vitro and in vivo tests: the in vitro test assessed the cellular response in terms of viability, differentiation and synthetic activity, while the in vivo test evaluated the healing capacity of bone defects treated with these biomaterials. GEL and SL2 induced a similar response for viability and differentiation of MG63 osteoblast-like cells after a 7-day culture, while SL6 caused a higher production of both interleukin-6 and type I collagen. Since the results showed that the materials were biocompatible and not cytotoxic in vitro, the in vivo study was carried out: materials were implanted, under general anesthesia, in critical size defects of rabbit femoral condyles; after 4 and 12 weeks, the healing rates and the quality of the regenerated bone were histomorphometrically calculated. The SL2-treated defects healed better at 12 weeks with a more similar microarchitecture of the newly formed bone to normal bone in comparison with other materials, as demonstrated by bone volume fraction and trabecular thickness values.

Sandblasted titanium osteointegration in young, aged and ovariectomized sheep.

To evaluate how aging and estrogen deficiency influence the success rate of Sandblasted Titanium (Ti/SA) implants, the osteointegration of Ti/SA rods was studied in the cortical and trabecular bone of 5 young, 5 aged and 5 ovariectomized (OVX) sheep. The characterization of the host bone by transiliac biopsies of the iliac crest showed a progressive rarefaction of trabecular bone in aged and OVX animals when compared to young ones. A significant reduction, both in cortical and trabecular bone, of the osteointegration rate of Ti/SA rods in the presence of estrogen deficiency compared to young animals was observed, while only a minor reduction was observed in aged animals. These results were confirmed by the pushout test in cortical bone. Bone quality affected the biological response of bone to Ti/SA implants in both trabecular and cortical bone; consequently, strategies to maximize the bone osteogenic properties of osteoporotic patients should be adopted.

In vitro culture of mesenchymal cells onto nanocrystalline hydroxyapatite-coated Ti13Nb13Zr alloy.

In this study we coated a new biocompatible, nanostructured titanium alloy, Ti13Nb13Zr, with a thin layer of hydroxyapatite nanocrystals and we investigated the response of human bone-marrow-derived mesenchymal cells. The coating was realized using a slightly supersaturated CaP solution, which provokes a fast deposition of nanocrystalline hydroxyapatite. A thin layer of deposition is appreciable on the etched Ti13Nb13Zr substrates after just 1.5 h soaking in the CaP solution, and it reaches a thickness of 1-2 mum after 3 h soaking. The coating seems thinner than that deposited on Ti6Al4V, which was examined for comparison, likely because of the different roughness profiles of the two etched alloys, and it is constituted of elongated HA nanocrystals, with a mean length of about 100 nm. Mesenchymal stem cells were seeded onto coated and uncoated Ti alloys and cultured for up to 35 days. Cell morphology, proliferation and differentiation were evaluated. The cells display good adhesion and proliferation on the uncoated substrates, whereas the presence of hydroxyapatite coating slightly reduces cell proliferation and induces differentiation of MSCs towards a phenotypic osteoblastic lineage, in agreement with the increase of the expression of osteopontin, osteonectin and collagen type I, evaluated by means of rt-PCR. Type I collagen expression is higher in Ti13Nb13Zr MSC culture compared to Ti6Al4V, standing for a more efficient extracellular matrix deposition.

Destination of titanium particles detached from titanium plasma sprayed implants.

Small titanium particles may detach from titanium plasma sprayed (TPS) implants during implant insertion, when no preliminary tapping is used, probably for the frictional force between titanium coating and host bone. Aim of this study was to investigate the destination of these titanium particles observed in the peri-implant environment. Twenty-four TPS screws were implanted in tibiae of two sheep. Fourteen and 90 days after implantation the implants with the surrounding bone were removed and processed to be analyzed by light microscope and scanning electron microscope (secondary electron and back-scattered electron probes). Small titanium particles detached from the unloaded TPS implants were observed both in the newly-formed bone matrix and in marrow tissue. Histomorphometric analysis showed that both at 14 and 90 days after implantation the titanium particles appeared more concentrated in marrow tissue than in calcified bone matrix, decreasing by 66.4% over time. In particular, smaller particles (<250 microm(2)) decreased by 81.5%, whereas the larger ones (250-2000 microm(2)) did not show any significant variations over time, suggesting that most of the smaller particles may undergo to ionic dissolution, probably migrating into the peri-implant marrow lacunae. A slight migration of titanium particles from the implant surface towards the more distant peri-implant tissues was also demonstrated over time.

[The risk of inhalable wood dust: assessment of workers exposure wood working factories]. / Il rischio da polveri di legno inalabili: valutazione dell'esposizione professionale nelle falegnamerie.

The International Agency for Research on Cancer RC) has classified wood dust as carcinogenic to humans based on demiological and experimental evidence. Exposure to wood dust may use respiratory and dermal symptoms and diseases. The aim of this work was to estimate occupational exposure to inhalable wood dust adopting the formal procedure described by UNI EN 689/97. The exposure of 23 workers in three different working day was measured. In total, 69 personal air samplings were carried out at five wood working factories. Inhalable fraction of airborne dust was collected on 5 microm pore size, 25 mm diameter PVC filters utilizing the IOM samplers. The quantity of the wood dust was determined with gravimetric method. The results show that about 13% of the exposure values exceed the limit of 5 mg/m3 specified by the Italian Law Decree 66/2000 and about 48% of personal exposures are lower then the limit value. Prevention measures, technological solutions and personal protection equipment should be adopted in order to reduce worker's exposure.

[Mount Reventino greenstone: assessment of tremolite fibre dispersion in the workplace]. / Le pietre verdi del Reventino: valutazione della dispersione di fibre di tremolite nelle attività lavorative.

BACKGROUND: Mount Reventino, a massif located in the Calabria Region of Italy, has several ophiolite outcrops of greenstone. These deposits are an important economical resource in the surrounding area. Some rock layers contain tremolite, a type of asbestos fibre. OBJECTIVES: The aim of this paper was to analyze the chemical and physical structure of the outcrops of Mount Reventino, and to assess and reduce the risk to workers associated with exposure to airborne fibres. METHODS: Personal and environmental samples were collected and analysed by Scanning Electron Microscopy equipped with energy-dispersive X-ray analysis. RESULTS: The analysis of samples showed a difference in mineralogical features not only between the quarries under study, but also between the two opposite sides of the mountain. Exploitation of the quarries produces a fibre dispersion that is higher than the natural emission. Occupational exposure to asbestos fibres during greenstone transformation was confirmed by by the results of analysis of the collected samples. CONCLUSIONS: This study made it possible to identify working activities with highest exposure to asbestos and establish the correct procedures to abate fibre dispersion, in order to reduce the correlated risk. Environmental samples collected in the urban area surrounding the quarries showed that the asbestos fibre concentrations were very low, however, further studies are needed in order to confirm these findings.

Metastatic breast cancer: an updating.

This article reports on recent advances on metastatic breast cancer. Detection, prognostic factors, predictors of response to therapy and therapy, with particular regard to targeted therapies, were examined. DETECTION: Unlike current guidelines that yet do not routinely recommend intensive clinical-instrumental post-operative follow-up of breast cancer patients, relatively large data collected in the last decades have shown that an intensive post-operative follow-up with 'dynamic evaluation' of a suitable tumour marker panel precedes a few months as average the clinical and/or instrumental sign of a pending relapse in most relapsed patients and largely limits the use of the common instrumental examinations. PROGNOSIS AND THERAPY PREDICTORS: Disease-free interval (DFI)24 months and disease confined to bony skeleton are prognostic factors more often correlated with relatively poor or prolonged survival, respectively. Estrogen receptor (ER) expression in primary tumour and at the relapse correlates strongly with response to salvage hormone therapy and data from large trials showed that 38-59% of ER and/or PR+ post-menopausal patients had clinical benefit from first line tamoxifen or aromatase inhibitors. An inverse correlation of ER with epidermal growth factor receptor (EGFR) has been found. The co-expression of HER-2/neu and/or elevated serum HER-2/neu protein level were associated with a low rate and shorter duration of response of ER+ patients to first line hormone therapy. Accordingly, ER-EGFR- compared with ER-EGFR+ tumours are usually more responsive to endocrine therapy. High class III beta-tubulin expression or fall in insulin-like growth factor binding protein-3 (IGFBP-3) from baseline levels have been found to significantly predict resistance to chemotherapeutic agents. THERAPY: Liposomes as carrier of doxorubicin (Caelix, Evacet, Myocet) is one approach to decrease the anthracycline-related cardiac toxicity. Weekly paclitaxel or docetaxel and oral formulation of vinorelbine and 5-fluorouracil (5-FU) (capecitabine) provide new effective and well tolerated options that reach greater dose intensity and cumulative dose than with the conventional schedules. As to the so called 'tailored' or targeted therapies, the more potent and highly selective third generation of aromatase inhibitors (letrozole, anastrozole, exemestane) targeting ER+ tumours by estrogen deprivation, challenge tamoxifen as current standard first line therapy in postmenopausals. One pilot study showed that stimulation of cellular immunity by the addition of beta-interferon-interleukin-2 sequence in patients on clinical benefit on first line tamoxifen significantly prolonged median overall survival (OS) and duration of response compared to that observed in similar patients only treated with tamoxifen. Trastuzumab, a humanised monoclonal antibody to extracellular domain of HER-2, plus conventional chemotherapy has become a standard of care for women with overexpressing HER-2 tumours. Bevacizumab is a recombinant humanised monoclonal antibody to vascular endothelial growth factor (VEGF) that in refractory metastatic breast cancer doubled the response rate of capecitabine although it did not affect survival. Finally, the so called 'oligometastatic' and a few stage IV diseases are conditions amenable to be rendered with no evidence of disease (NED) after local surgery and/or radiation. In both, as well as in complete responders to chemotherapy, minimal residual disease (m.r.d.) likely continues to be present. Recent data suggest that 'biological' therapy (immunomodulators and/or retinoids with or without hormone therapy), might be suitable to be successfully tested in these patients as maintenance treatment given soon after local intervention or chemotherapy.

A new chemical etching process to improve endosseous implant osseointegration: in vitro evaluation on human osteoblast-like cells.

The development of novel mechanical and chemical surface modification treatments to improve the osteointegration properties of osseointegrated dental implants is nowadays a topic of great applicative interest. The aim of the present study was to analyse the role of surface topography and chemistry of four different surface treatments on titanium by an in vitro human osteosarcoma immortalised cell line model (MG63). The surface treatments considered were (a) machined titanium, (b) chemical etched on machined titanium, (c) sandblasted titanium and (d) chemical etching on sandblasted titanium. Chemical and physical surface properties were investigated by Scanning Electron Microscopy, Thin Film-X ray Diffraction and by Laser Profilometry. The in vitro biological response was characterised using the MG63 cell line by elution cytotoxicity tests, cell morphology, adhesion, proliferation activity, alkaline phosphatase activity and total DNA content in order to show a relationship between osteoblast response and surface features. Chemical and physical characterisation showed that the considered treatments differently modify the surface morphology in the micro and sub-micrometric scale. Although some differences in alkaline phosphatase activity were observed in the biological characterisation, depending on the specific material's surface finishing, the results showed that cells were well responsive on all the tested materials and grew and differentiated with similar proliferation rate.

Thyroid nodule evaluation: what have we really learned from recent clinical guidelines?

Recent guidelines for the evaluation of thyroid nodules clarify the diagnostic algorithm while also reporting important differences. The performance of fine needle aspiration (FNA) for cytological examination follows serum TSH determination and thyroid ultrasonography. Thyroid scintigraphy is recommended following a low TSH value and/or FNA yielding an indeterminate follicular cytology. The use of thyroid ultrasonography is the source of some controversy: though it is recommended as a principal first test, its real-time use to guide FNA ranges from routine to only following an FNA yielding an inadequate or nondiagnostic cytological result. In clinical practice, the proportion of physicians utilizing ultrasonography, scintigraphy and FNA varies and frequently deviates from recommended guidelines. The development of guidelines is necessary to bring about consistency and optimization to the diagnostic work-up of thyroid nodules. It is likely that novel diagnostic procedures, such as molecular markers, large needle aspiration biopsy and thyroid imaging with tracers beyond conventional radioactive iodine or (99m)Tc pertechnetate, will lead to improved performance and implementation of guidelines.