The role of intraoperative frozen section of central neck lymph nodes in the management of patients preoperatively diagnosed with low- risk differentiated cancer.

INTRODUCTION: Histological examination during surgery (FS) has a place in the surgical management of differentiated thyroid carcinoma (DTC). Extending the indication for limited surgery to 4 cm tumor size (ATA guidelines 2015) cytologically verified DTCs, increases the emphasis on accurate patient selection. In our work, we reflected on the effectiveness of FS and its relationship to optimal patient management. METHODS: In a single-center retrospective study, we evaluated the documentation of patients indicated for primary surgery for DTC from January 1, 2016 to December 31, 2020 - there was 489 patients collectively, 121 were men, median age was 50 years (1681), 73 patients (female, age 1845 years) with preoperatively identified low-risk DTC (size 1140mm) were indicated for lobectomy. RESULTS: 34 patients (46.6%) did not meet the criteria for limited surgery 15 patients were identified from FS of the lymph nodes of the central compartment (LNCK) (15 of 25 patients) - 1 patient with false negative result and 6 patients with FS of the thyroid gland (SH) (6 / 41) - 11 patients with false negative findings. Two-step OP surgery was performed on 13 patients (17.8%). FS of LNCK identified high-risk cancer and reduced the risk of two-step surgery compared to the group of patients in whom FS was not performed or was performed from thyroid gland. The difference was statistically significant (OR 1.93, p=0.026). CONCLUSION: Approximately ½ of the patients from preoperatively identified low-risk cancers in our cohort met the criteria for limited surgery. About 30% of them eventually needed a two-step operation. Perioperative examination of LNCK helps to perform radical surgery at one time.

New Ni-free superelastic alloy for orthodontic applications.

A potential new Ni-free Ti alloy for biomedical applications was assessed in order to investigate the superelastic behavior, corrosion resistance and the biocompatibility. The alloy studied was Ti19.1Nb8.8Zr. The chemical composition was determined by X-ray microanalysis, the thermoelastic martensitic transformation was characterized by high sensitivity calorimeter. The critical stresses were determined by electromechanical testing machine and the corrosion behavior was analyzed by potentiostatic equipment in artificial saliva immersion at 37°C. The results were compared with six different NiTi orthodontic archwire brands. The biocompatibility was studied by means of cultures of MG63 cells. Ni-free Ti alloy exhibits thermoelastic martensitic transformation with Ms=45°C. The phase present at 37°C was austenite which under stress can induce martensite. The stress-strain curves show a superelastic effect with physiological critical stress (low and continuous) and a minimal lost of the recovery around 150 mechanical cycles. The corrosion resistance improves the values obtained by different NiTi alloys avoiding the problem of the Ni adverse reactions caused by Ni ion release. Cell culture results showed that adhered cell number in new substrate was comparable to that obtained in a commercially pure Ti grade II or beta-titanium alloy evaluated in the same conditions. Consequently, the new alloy presents an excellent in-vitro response.

In vitro response of preosteoblastic MG63 cells on Ni-free Ti shape memory substrates.

Ni-free Ti alloys are a potential strategy to overcome the risk of Ni-adverse reactions and rigidity mismatch for implant materials. Here, we report the biological behavior induced for two promising candidate alloys--Ti19.1Nb8.8Zr (M(S) temperature of 46°C and elastic modulus of 74 GPa) and Ti41.2Nb6.1Zr (elastic modulus of 67 GPa)--on cultured MG63 cells, as well as their physical and chemical properties. Contact angle results revealed the hydrophobic character of the former alloy (59.02° ± 2.35°) attributed to the presence of the martensitic phase, while the latter one presented a hydrophilic response (67.77° ± 2.78°). Results showed also that the cell adhesion response (after 4 and 8 h of incubation) in both substrates was not statistically different to that obtained in the cp Ti as control material. These surfaces induced well spread cell morphology with cytoplasmic extension like filopodia of up to 100 µm even at short culture times and presented an uninterrupted proliferation after longer incubation times (9 days). A decrement in the proliferation rate was appreciated from the Ti19.1Nb8.8Zr surface at that time, which was attributed to an earlier activation of the cell differentiation stage, as confirmed by the twofold increment of alkaline phosphatase activity. The results also evidenced that the presence of a 2 nm thick layer of amorphous Nb2O5, which was detected on both alloys, has a significant effect on cell behavior favoring the cell adhesion and morphology response of the new alloys studied.

Anti-inflammatory constituents of Mortonia greggii Gray.

A new phytochemical study of Mortonia greggii (Celastraceae) afforded four friedelan derivatives (1-4), three lupanes (5-7), retusine (8), two esterified polyhydroxyagarofurans (9-10), mortonin C (11) and photomortonin C (12). The anti-inflammatory activity on carrageenan and 12-O-tetradecanoylphorbol-13-acetate induced models of inflammation, as well as the ability to inhibit the nitric oxide (NO) produced by lipopolysaccharide-stimulated mouse peritoneal macrophages were evaluated for the main metabolites. Our results showed that the friedelan dehydrocanophyllic acid methyl ester (1) exhibits an anti-inflammatory effect which could be related to an inhibition of prostaglandin and NO production. The activity of lupeol (5), 29-hydroxylupeol (6) and 29-hydroxylupenone (7) might be involved with the prostanoid synthesis. The presence of the hydroxy groups in 6 appears to be important for activity. The edema inhibition capacity of retusine (8) could be related to a reduction of the prostaglandin production. The agarofuran derivative 10 is an NO inhibitor whose activity is probably not involved in the synthesis of prostaglandins.