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

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

Poor warfarin anticoagulation in long-term thromboprophylaxis: a survey in a southern Croatian county

Aim: To assess the quality of real-life warfarin anticoagulation in patients requiring chronic thromboprophylaxis in a southern Croatian county. Methods: We retrospectively analyzed international normalized ratio (INR) values determined over one year (2016-2017) at the Zadar County General Hospital in warfarin-treated patients requiring chronic thromboprophylaxis. The values represent 83.0% of all INRs and were determined in 84.0% of all warfarin-treated patients in the county during the observed period. Results: Overall 31 162 INRs were taken from 3697 patients, 2240 of whom (20 851 INRs, 3-56 per patient, median 9) were referred with diagnoses requiring chronic thromboprophylaxis: mainly atrial fibrillation/flutter (n = 1508, 14 902 INRs) but also cardiac implants, valvular disease, severe heart failure, and cerebrovascular disease (“other”, n = 732, 5949 INRs). Only 50.1% of all INRs were within the target range, 2.0-3.5, while 43.6% were 3.5. Median crude individual proportion of INRs within the range was 50.0%, while it was 42.0% for INRs <2.0. Only 23.0% of the patients had ≥70% of the INRs within the target range (adequately anticoagulated), while 35.5% had ≤33.3% of the INRs within the range. Conversely, 66.5% of the patients had ≥33.3% INRs <2.0. Adjusted probability of adequate anticoagulation in atrial fibrillation/flutter patients was consistently 25.5% to 27.7%, regardless of the number of determined INRs, while in patients with other conditions it increased from 9.5% to 25.2% with a higher number of INRs. Conclusion: The achieved level of warfarin anticoagulation in this real-life setting is far below what is needed for effective long-term thromboprophylaxis

Analysis of job stress in workers employed by three public organizations in Serbia

Objectives: The present study analyzes job stress in terms of education, age and the presence of cardiovascular and endocrine/metabolic diseases. Material and Methods: A total of 411 workers employed by three public organizations completed the Job Content Questionnaire to classify their jobs based on the job strain model. Data about health condition, education and habits was obtained by the use of medical examinations and an interview. Results: The analysis of the completed Job Content Questionnaires indicates that workers with high education have significantly higher decision latitude (DL) than low-educated workers (one-way ANOVA, p < 0.0001). DL was also different between age groups (one-way ANOVA, p < 0.0001) - the highest DL values were observed in the oldest group, while the lowest DL mean was found in the youngest group. Psychological job demands (PJD) and social support (SS) were not significantly different between educational and age groups. The frequency of job stress categories was significantly different between low and highly-educated workers (χ2 test, df = 3, p < 0.0001) and also between different age groups (χ2 test, df = 6, p < 0.0001). The majority of highly-educated men were exposed to "active" jobs (high PJD and high DL). Most frequently, men older than 45 years experienced jobs with high DL ("active" and "low strain"), men aged 35 to 45 years were exposed to jobs with high PJD ("high strain" and "active") while the majority of men younger than 35 years were exposed to jobs with low DL ("high strain" and "passive"). No association between cardiovascular and endocrine/metabolic disorders and different job stress categories was observed. Conclusion: "High strain" and "passive" jobs were most frequently identified among low-educated and young men. Despite the absence of association between job stress and cardiovascular and endocrine/metabolic diseases, we recommend prevention of work stress, particularly in the case of low-educated workers and workers younger than 45 years exposed to unfavorable job stress categories

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