Study of the mechanical properties of a ceramics of orthopedic and dental use

The study of the preparation of ceramics is consisted in sintering a hardened cement, wich is composed of mixture of three calcium phosphates : tetracalcium phosphate (Ca4(PO4)2O), -tricalcium phosphate (-Ca3(PO4)2) and monocalcium phosphate (Ca(H2PO4)2.H2O).After wetting, the cement evolved towards an apatitic phase while hardening. To check the effect of certain factors on the resulting ceramics, a complete central composite design of four variables (liquid/solid ratio, stoichiometric coefficient of monocalcium phosphate, rate of increase in temperature and duration of landing of termpertaure) was set up. The equation of the model and optimal conditions were defined

Controlled release properties and final macroporosity of a pectin microspheres–calcium phosphate composite bone cement

The use of calcium phosphate cements (CPC) is restricted by their lack of macroporosity and poor drug release properties. To overcome these two limitations, incorporating degradable polymer microparticles into CPC is an attractive option, as polymer microparticles could help to control drug release and induce macroporosity after degradation. Although few authors have yet tested synthetic polymers, the potentiality of polysaccharides’ assuming this role has never been explored. Low-methoxy amidated pectins (LMAP) constitute valuable candidates because of their biocompatibility and ionic and pH sensitivity. In this study, the potentiality of a LMAP with a degree of esterification (DE) of 30 and a degree of amidation (DA) of 19 was explored. The aim of this study was to explore the influence of LMAP microspheres within the composite on the cement properties, drug release ability and final macroporosity after microspheres degradation. Three LMAP incorporation ratios, 2%, 4% and 6% w/w were tested, and ibuprofen was chosen as the model drug. In comparison with the CPC reference, the resulting composites presented reduced setting times and lowered the mechanical properties, which remained acceptable for an implantation in moderate-stress-bearing locations. Sustained release of ibuprofen was obtained on at least 45 days, and release rates were found to be controlled by the LMAP ratio, which modulated drug diffusion. After 4 months of degradation study, the resulting CPC appeared macroporous, with a maximum macroporosity of nearly 30% for the highest LMAP incorporation ratio, and interconnectivity between pores could be observed. In conclusion, LMAP appear as interesting candidates to generate macroporous bone cements with tailored release properties and macroporosity by adjusting the pectin content within the composites

Characterization of a calcium phospho-silicated apatite with iron oxide inclusions

An iron oxide containing calcium phosphate–silicate hydroxyapatite was synthesized by calcination at 900 °C of a sample obtained by precipitation in basic aqueous solution of Ca, P, Si, Fe and Mg containing acidic solution made from dissolution of natural minerals. XRD and FTIR were used for crystallographic characterization of the main apatitic phase. Its composition was determined using ICP-AES. EDX coupled with SEM and TEM evidenced the heterogeneity of this compound and the existence of iron–magnesium oxide. Magnetic analyses highlighted that this phase was non-stoichiometric magnesioferrite (Mg1.2Fe1.8O3.9) spherical nanoparticles. Those analyses also put into evidence the role of calcination in synthesis. Carbonates detected by FTIR and estimated by SEM-EDX in non-calcinated sample were removed from apatitic structure, and crystallization of apatite was enhanced during heating. Moreover, there was phase segregation that led to magnesioferrite formation

X-ray diffraction study of cadmium hydroxyapatite

Solid solutions of cadmium and calcium hydroxyapatite [Ca10−x Cdx (PO4)6 (OH)2 (0 ≤ x ≤ 10)] were synthesized by a wet process in a basic medium. The lattice dimensions of these compounds vary linearly with the atom percent cadmium. The distribution of the calcium and cadmium ions between two non- equivalent crystallographic sites, (1) and (2), were determined by the Rietveld method. The site-occupancy factors of atoms indicate a slight preference of cadmium for site (2) in the apatite structure

To avoid operating on pseudo tumoral pulmonary infarctions mimicking lung cancer

Pulmonary infarction usually appears as a hump-shaped triangular opacity with its base applied to a pleural surface. In some cases, pulmonary infarctions may appear as a pseudo tumoral opacity mimicking lung cancer. Thoracotomy could be prevented by repeating CT scan in properly selected patients.Pan African Medical Journal 2012; 12:1

RE: Role of Duplex Doppler US for Thyroid Nodules: Looking for the "Sword" Sign

Duplex Doppler US may be useful for the detection of thyroid malignancies that show either anarchic winding or penetrating "sword like" neoangiogenic vessels. It may be helpful in selecting nodules that should undergo fine needle aspiration biopsy

An Independent Analysis of a Retrospective Cohort of 30,423 Covid-19 Patients Treated at IHU-Mediterranean in Marseille, France: Part 1, Efficacy of early Treatment with Hydroxychloroquine and Azithromycin

A cohort of 30,423 Covid-19 patients treated between March 2020 and December 2021 at the IHU-Méditerranée Infection in Marseille (France) was retrospectively analyzed in terms of treatment attempted and disease worsening factors to quantify efficacy with respect to the composite endpoint of transfer to intensive care unit or death, within a couple of months (56 days) from admission. Within limitations of the data and of the models, after adjustment for sampling biases, multivariate logistic regression analyses were performed to determine unadjusted and adjusted odds ratios (ORs) for the subset of patients having received the combined treatment hydroxychloroquine plus azithromycin (HCQ-AZ) or no specific treatment (i.e. no HCQ, no AZ and no ivermectin (IVM)) (24,943 patients). An efficacy of 58% in reducing the risk of ICU transfer and death was measured (HCQ-AZ unadjusted OR = 0.499; 95%CI = [0.343; 0.727], p \u3c 0.001) (HCQ-AZ adjusted OR = 0.419; 95%CI = [0.327; 0.539], p \u3c 0.001). AZ without HCQ but associated with ivermectin in 31.3% of the cases was significantly active as well with respect to no specific treatment, with a measured efficacy of 27% (unadjusted OR = 0.720, 95%CI = [0.574; 0.905] p = 0.005 and adjusted OR = 0.727, 95%CI = [0.608; 0.870] p \u3c 0.001). Interactions between HCQ-AZ and the model covariates were systematically explored. No interaction between HCQ-AZ treatment and vaccination was detected. Statistically significant favorable interactions were detected between HCQ-AZ treatment and male sex, age categories ≥ 50 years, the UK variant and when the variant was not determined, obesity, chronic obstructive pulmonary disease (COPD), cancer, immunodeficiency, confirming the high efficacy of this early treatment. No statistically significant unfavorable interaction of HCQ-AZ with any covariate was detected. Limitations of the models and their implications for the results are discussed extensively

Chemical and structural characterization of natural phosphate of Hahotoe (Togo)

 Chemical and structural characterizations of natural phosphates of Hahotoe (Togo) have been performed. From chemical analysis and FTIR study, it can be concluded that the material is carbonated fluoroapatite with poor substitution of calcium by cadmium and manganese. From these results, the molecular formula proposed is: Ca9.925Cd0.004Mn0.013[(PO4)5.886(CO3)0.113]F2.Powder X-ray diffraction fitting results confirm that compound belongs to the apatite family crystallising in the hexagonal system, space group P63/m. The cell parameters are: a = 9.3547(5) Å; c = 6.8929(4) Å. KEY WORDS: Natural phosphate, Fluoroapatite, Infrared, X-Ray diffraction, Rietveld structure refinement  Bull. Chem. Soc. Ethiop. 2003, 17(2), 139-146

An Independent Analysis of a Retrospective Cohort of 30,423 Covid-19 Patients Treated at IHU-Mediterranean in Marseille, France: Part 2, a Real-life Assessment of Covid-19 Vaccination Efficacy

A cohort of 30,423 Covid-19 patients treated between March 2020 and December 2021 at the IHU-Méditerranée Infection in Marseille (France) was retrospectively analyzed in terms of treatment attempted and disease worsening factors to quantify vaccination efficacy with respect to the composite endpoint of transfer to intensive care unit or death, within a couple of months (56 days) from admission. Within limitations of the data and of the models, after adequate adjustment for sampling biases, multivariate logistic regression analyses were performed to determine unadjusted and adjusted odds ratios (ORs) for the subset of patients admitted after the Covid-19 vaccination program was started early 2021 (16,063 pts) (vaccination unadjusted OR = 0.498, 95%CI = [0.313 ; 0.794], p = 0.003 and adjusted OR = 0.462, 95%CI = [0.307 ; 0.670] , p \u3c 0.001). Statistically significant interactions (p \u3c 0.05) were detected between vaccination and some covariates : favorable with the virus variant Delta and possibly obesity as well (p=0.084), and unfavorable with age \u3e 89 years, Covid-19 disease severity, immunodeficiency and possibly chronic obstructive pulmonary disease (COPD) as well (p=0.072), confirming its capacity to worsen the Covid-19 disease condition not only in some cases of severe underlying chronic illness but also in the elderly patients and when the disease severity necessitated patient\u27s hospital admission. Additionally, sensitivity analysis showed that vaccination had no efficacy below 50 years of age (adjusted OR = 1.35; 95%CI = [0.09; 8.84], p = 0.781)