Optimization of the spark plasma sintering conditions for the consolidation of hydroxyapatite powders and characterization of the obtained products

A comparative investigation regarding the consolidation behavior displayed by three commercially available hydroxyapatite powders during Spark Plasma Sintering (SPS) is performed in this work. Starting powders are different in terms of purity, particle size, morphology and thermochemical stability. A completely dense product without secondary species is produced by SPS at 900 °C, when starting from highly pure powders with relatively small sized particles and grains. The resulting consolidated material, consisting of sub-micrometer sized hydroxyapatite grains, exhibits optical transparency and good mechanical properties. On the other hand, temperature levels up to 1,200 °C are needed to sinter powders with larger particles. This holds also true when relatively finer powders are used, also containing CaHPO4, are used. In both the latter cases products with coarser microstructures and/or significant amount of β-TCP, as a result of hydroxyapatite decomposition, are obtained. Optical, chemical resistance and mechanical properties of the resulting dense materials are correspondingly deteriorated

Sviluppo e caratterizzazione di materiali innovativi a base di idrossiapatite e vetro bioattivo

The difference in purity, particle size, microstructure, and thermo-chemical stability of three commercially available hydroxyapatite powders are found to play an important role during their consolidation using Spark Plasma Sintering (SPS) as well as strongly affect the characteristics of the resulting sintered bodies. A fully dense material without secondary phases was obtained by SPS at 900°C, when using the relatively small sized, with refined grains and high purity powders. The sintered product, consisting of sub-micrometer sized hydroxyapatite grains, displayed optical transparency and good mechanical properties. In contrast, the higher temperature levels (up to 1200 °C) needed to sinter powders with larger particles, or finer ones which contain additional phases, lead to products with coarser microstructures and/or significant amount of β-TCP as a result of HAp decomposition. Optical characteristics, hardness and elastic modulus of the resulting sintered samples are correspondingly worsened. Thanks to the favorable response bioglass materials display during their interaction with biological tissues, they have become one of the most important and investigated class of ceramics for biomedical application. In particular, as a consequence of the several chemico-physical phenomena involved at the glass-physiological fluids interface, a bone-like hydroxycarbonate apatite (HCA) layer is formed on the biomaterial surface, so that a strong bond between the latter one and tissues can be established. It is well known that mechanical and biological properties of bioactive glasses are significantly affected by the relative amounts among the different oxide constituents as well as the sintering conditions adopted to consolidate the initial amorphous powders. One of the most important aspect to consider in this regard is represented by the tendency of the material to crystallize during heat treatments, as the extensive crystallization of the bioglass negatively influence its bioactivity properties. In particular, the onset time for the formation of the HCA layer during glass exposure to a simulated body fluid (SBF) solution is delayed by crystallization

Chemo-conization in Early-sTage cERvical caNcer >2 cm scheduled for fertilItY-sparing approach: an analysis of the ETERNITY project

Objective: To investigate the safety of neoadjuvant chemotherapy and conization in early-stage cervical cancer with a tumor size >2 cm using a fertility-sparing approach. Methods: The ETERNITY project is a retrospective, multi-institutional study that collected data from patients with early-stage cervical cancer undergoing fertility-sparing treatment. In the present study, we report the outcomes of stage IB2 to IB3 cervical cancer undergoing nodal assessment, neoadjuvant chemotherapy, and conization. A propensity-matching algorithm was used to compare patients who underwent upfront radical surgery. Results: A total of 395 patients were included in the ETERNITY project. Among these, 25 underwent a fertility-sparing attempt with nodal assessment, neoadjuvant chemotherapy, and conization. The median (range) patient age was 37 (24-41) years. Four (16%) patients with positive nodes required definitive chemo-radiation. Twenty-one (84%) patients received neoadjuvant chemotherapy. Two (8%) patients with stable disease underwent radical hysterectomy, whereas the remaining 19 (76%) patients who achieved a clinical response underwent cervical conization. Three (12%) patients underwent radical hysterectomy owing to persistent positive margins, leaving 16 (64%) patients who completed the planned fertility-sparing attempt. After a median (range) follow-up of 36.2 (21.9-88) months, 3 recurrences occurred. Two patients with cervical recurrence underwent hysterectomy, while 1 patient who received definitive chemoradiotherapy owing to the presence of positive nodes developed distant recurrence. Regarding obstetric outcomes, 6 patients attempted to conceive, and 4 (66.7%) pregnancies were achieved (1 was achieved with assisted reproductive technology). In a propensity-matched group of patients who underwent upfront radical surgery, no differences in morbidity or survival rates were recorded. Conclusions: Neoadjuvant chemotherapy followed by conization should be investigated in selected patients with cervical cancer who wish to preserve their childbearing potential. Further prospective studies are needed to assess the long-term safety and identify predictors of response. Clinical trial identifier: NCT06351228

Acute Delta Hepatitis in Italy spanning three decades (1991–2019): Evidence for the effectiveness of the hepatitis B vaccination campaign

Updated incidence data of acute Delta virus hepatitis (HDV) are lacking worldwide. Our aim was to evaluate incidence of and risk factors for acute HDV in Italy after the introduction of the compulsory vaccination against hepatitis B virus (HBV) in 1991. Data were obtained from the National Surveillance System of acute viral hepatitis (SEIEVA). Independent predictors of HDV were assessed by logistic-regression analysis. The incidence of acute HDV per 1-million population declined from 3.2 cases in 1987 to 0.04 in 2019, parallel to that of acute HBV per 100,000 from 10.0 to 0.39 cases during the same period. The median age of cases increased from 27 years in the decade 1991-1999 to 44 years in the decade 2010-2019 (p < .001). Over the same period, the male/female ratio decreased from 3.8 to 2.1, the proportion of coinfections increased from 55% to 75% (p = .003) and that of HBsAg positive acute hepatitis tested for by IgM anti-HDV linearly decreased from 50.1% to 34.1% (p < .001). People born abroad accounted for 24.6% of cases in 2004-2010 and 32.1% in 2011-2019. In the period 2010-2019, risky sexual behaviour (O.R. 4.2; 95%CI: 1.4-12.8) was the sole independent predictor of acute HDV; conversely intravenous drug use was no longer associated (O.R. 1.25; 95%CI: 0.15-10.22) with this. In conclusion, HBV vaccination was an effective measure to control acute HDV. Intravenous drug use is no longer an efficient mode of HDV spread. Testing for IgM-anti HDV is a grey area requiring alert. Acute HDV in foreigners should be monitored in the years to come

Classical Bioglass®and innovative CaO-rich bioglass powders processed by Spark Plasma Sintering: a comparative study

Densification and crystallization phenomena taking place when a recently developed CaO-rich bioactive glass and conventional 45S5 Bioglass® are processed by Spark Plasma Sintering (SPS) are examined. Fully dense and wholly amorphous products can be obtained from the new glass composition at 730°C after 2min dwell time. Moreover, temperatures equal or higher than 830°C are needed to induce crystallization (α- and β-CaSiO3) in the parent glass. Conversely, Na6Ca3Si6O18 crystals are formed in sintered 45S5 samples produced under optimal conditions (550°C, 2min), although the glassy character is still preserved.Products resulting from the innovative glass powders generally display higher hardness and local elastic modulus. Devitrification also provides improvements in this system. In contrast, mechanical properties become slightly worsen when classical bioglass is processed at 600. °C. This can be probably associated to the corresponding decrease in compactness which, apparently, overcomes the benefits arising from the crystallization progress

C9ORF72 repeat expansion and bipolar disorder–is there a link? No mutation detected in a Sardinian cohort of patients with bipolar disorder

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<i>Salmonella</i> and <i>Yersinia enterocolitica</i> through the pig meat chain in Sardinia: occurrence, antimicrobial resistance and genetic insight

The study aimed to characterize Salmonella and Yersinia enterocolitica detected in fattening pigs in Sardinia, examining genetic similarity and antimicrobial resistance of isolates from farms and slaughterhouses and evaluating carcass hygiene. Environmental samples were collected from six pig farms, and the same pigs were also sampled at the slaughterhouses. Palatine tonsils, mesenteric lymph nodes, colon content, and carcass surface samples were collected and tested for Salmonella and Y. enterocolitica. Antimicrobial resistance testing and whole genome sequencing were performed on all isolates. Carcass surface samples were tested for total aerobic colony count (ACC) and Enterobacteriaceae count (EBC). Y. enterocolitica was found in two farms (33%), while Salmonella was absent in environmental farm samples. At slaughterhouses, 13.1% of pigs were found positive for Salmonella (lymph nodes, colon content, and palatine tonsils samples), but Y. enterocolitica was not detected. Salmonella isolates were typed as monophasic S. Typhimurium ST34 and S. Goldcoast ST358, with few allelic differences among isolates of the same ST. Salmonella ST34 showed resistance towards ampicillin, streptomycin, sulfonamide, and tetracycline (blaTEM-1B, aph(3´´)-Ib, sul2 and tetB genes, R-type ASSuT). Y. enterocolitica isolates (biotype 2, ST853, and ST859) showed resistance to ampicillin and amoxicillin-clavulanic acid (blaA gene). Process hygiene criteria were generally met, with mean (log10 CFU/cm2 ± standard deviation) values for ACC and EBC being 2.23±0.74 and 0.75±0.81. Pigs of Sardinia are confirmed carriers of Salmonella and Y. enterocolitica, but overall hygienic status in farms and slaughterhouses in Sardinia is acceptable. Monophasic S. Typhimurium and Y. enterocolitica isolates showed typical resistance patterns. Monophasic S. Typhimurium ST34 isolates with R-type ASSuT are confirmed as epidemic clones

Sentinel node mapping, sentinel node mapping plus back-up lymphadenectomy, and lymphadenectomy in Early-sTage cERvical caNcer scheduled for fertilItY-sparing approach: The ETERNITY project

Objective: To investigate the safety of sentinel node mapping for patients with early-stage cervical cancer undergoing cervical conization plus nodal evaluation. Methods: The ETERNITY project is a retrospective, multi-institutional study collecting data of patients with early-stage cervical cancer undergoing fertility-sparing treatment. Here, we compared outcomes related to three methods of nodal assessment: sentinel node mapping (SNM), SNM plus backup lymphadenectomy (SNM&nbsp;+&nbsp;LND); pelvic lymphadenectomy (LND). Results: Charts of 123 patients (with stage IA1-IB1 cervical cancer) were evaluated. Median patients' age was 34 (range, 22-44) years. SNM, SNM&nbsp;+&nbsp;LND, and LND were performed in 32 (26&nbsp;%), 31 (25.2&nbsp;%), and 60 (48.8&nbsp;%) patients, respectively. Overall, eight (6.5&nbsp;%) patients were diagnosed with positive nodes. Two (3.3&nbsp;%), three (9.7&nbsp;%), and three (9.4&nbsp;%) patients were detected in patients who had LND, SNM&nbsp;+&nbsp;LND, and SNM respectively. Considering the 63 patients undergoing SNM (31 SNM&nbsp;+&nbsp;LND and 32 SNM alone), macrometastases, micrometastases, and isolated tumor cells were detected in four (3.2&nbsp;%), three (2.4&nbsp;%), and one (0.8&nbsp;%) patients, respectively. All patients with positive nodes discontinued the fertility sparing treatment. Other two patients (one (1.7&nbsp;%) in the LND group and one (3.1&nbsp;%) in the SNM group) required hysterectomy even after negative nodal evaluation. After a median follow-up of 53.6 (range, 1.3, 158.0) months, nine (7.3&nbsp;%) and two (1.6&nbsp;%) patients developed cervical and pelvic nodes recurrences, respectively. Disease-free (p&nbsp;=&nbsp;0.332, log-rank test) and overall survival (p&nbsp;=&nbsp;0.769, log-rank test) were similar among groups. Conclusions: In this retrospective experience, SNM upholds long-term oncologic effectiveness of LND, reducing morbidity