Warfarin should not be used for thromboprohylaxis in elective major orthopaedic surgery: a Croatian perspective

Aim: To identify modes of venous thromboembolism (VTE) prophylaxis in patients undergoing elective major orthopaedic surgery (total hip or knee arthroplasty, THA/TKA) at a single university-associated hospital in Croatia. ----- Methods: A retrospective analysis of consecutive patients subjected to THA or TKA over a two-year period (2014-2015) with a focus on anticoagulation during the first 15 post-surgical days (period of highest VTE risk). ----- Results: Of 603 identified patients three (0.5%) were not anticoagulated (haemophilia) and others received perioperative doses of low molecular weight heparins (LMWH). Overall, 228 (37.8%) patients received prophylaxis not involving warfarin, and 372 continued with short-term LMWH with switching to warfarin. They contributed a total of 1218 international normalized ratio (INR) values (median=3, range=1-8). These were consistently below the target INR range across the observed period. Between post-surgical days 6 and 15 (after the initial titration), 438 values were taken in patients treated with LMWH+warfarin and 92.7% were below, and only 6.8% within the target range; 580 values were taken in patients already switched to warfarin, 74% were below and only 25% within the range. ----- Conclusion: The prevailing mode of VTE prophylaxis was in a clear contrast to (then) actual professional guidelines, with inadequate monitoring and poor anticoagulation. There is no reason to expect a substantially different situation at other institutions across the country. The prevailing practice of VTE prophylaxis in major orthopaedic surgery in Croatia should be promptly abandoned and up-dated in agreement with the current state of the art

In vitro effects of ascorbic acid on viability and metabolism of patients’ osteosarcoma stem cells

Stagnation in novelties of osteosarcoma (OS) treatment indicates the need for new therapeutic methods. OS cancer stem cells (OS-CSC) are taught to have the ability to self-renew and develop mechanisms of anticancer drug resistance, and this is why it is difficult to eradicate them. Their metabolism has been recognized as a potential target of therapeutic action. Ascorbic acid (AA) is considered to act pro-oxidative against OS-CSC in vitro by oxidative effect and by inhibition of glycolysis. This study examined an in vitro impact of AA on OS-CSC metabolism isolated from patients\u27 biopsies, with the aim of better understanding of OS-CSC metabolism and the action of AA on OS-CSC. OS-CSC were isolated using a sphere culture system and identified as stem cells using Hoechst 33342 exclusion assay. Determination of the dominant type of metabolism of OS-CSC, parental OS cells, human mesenchymal stem cells (hMSC) and U2OS OS lineage before and after AA treatment was done by Seahorse XF (Agilent). Cytotoxicity of high-dose AA was confirmed by the MTT test and was proven for all the examined cell types as well as HEK293. Seahorse technology showed that OS-CSC can potentially use both glycolysis and oxidative phosphorylation (OXPHOS), and can turn to glycolysis and slow metabolic potential in unfavorable conditions such as incubation in AA

In vitro effects of ascorbic acid on viability and metabolism of patients’ osteosarcoma stem cells

Stagnation in novelties of osteosarcoma (OS) treatment indicates the need for new therapeutic methods. OS cancer stem cells (OS-CSC) are taught to have the ability to self-renew and develop mechanisms of anticancer drug resistance, and this is why it is difficult to eradicate them. Their metabolism has been recognized as a potential target of therapeutic action. Ascorbic acid (AA) is considered to act pro-oxidative against OS-CSC in vitro by oxidative effect and by inhibition of glycolysis. This study examined an in vitro impact of AA on OS-CSC metabolism isolated from patients’ biopsies, with the aim of better understanding of OS-CSC metabolism and the action of AA on OS-CSC. OS-CSC were isolated using a sphere culture system and identified as stem cells using Hoechst 33342 exclusion assay. Determination of the dominant type of metabolism of OS-CSC, parental OS cells, human mesenchymal stem cells (hMSC) and U2OS OS lineage before and after AA treatment was done by Seahorse XF (Agilent). Cytotoxicity of high-dose AA was confirmed by the MTT test and was proven for all the examined cell types as well as HEK293. Seahorse technology showed that OS-CSC can potentially use both glycolysis and oxidative phosphorylation (OXPHOS), and can turn to glycolysis and slow metabolic potential in unfavorable conditions such as incubation in AA