In breast cancer treatment, chemotherapy resistance is a major problem where many receptive tumors rebound and develop resistance. When provided in combination, cancer drugs are most successful, thus reducing the risk of developing resistant cancer cells. However, the evaluation of combination therapies has increased rapidly in recent years. Consequently, by repurposing old treatments, the discovery of additional medicines that may interact synergistically with chemotherapy is considered a current medical aim through discovering a new cancer medication or therapeutic strategy. The purpose of this research is to increase the anti-cancer activity of carboplatin (CP) by increasing the apoptotic effect of breast cancer cells (MCF-7) during in vitro experiments in combination with oxytetracycline. Our results showed a high synergistic effect between oxytetracycline and carboplatin, MCF-7 representative cell treated with carboplatin with/without different concentrations of oxytetracycline (5% and 10% of IC50). Oxytetracycline, which potentiated the action of carboplatin and/or had notable activity was reported as a single agent. This research demonstrated the synergistic relationship between oxytetracycline and carboplatin in viability assays. Surprisingly, our findings suggest that inhibiting treatment strategies can extend carboplatin’s therapeutic window, potentially allowing for cancer therapy.

Multi-class and multi-residue analyses are very complex procedures because of the physico-chemical properties of veterinary drug residues and other contaminants. The purpose of the study was to develop an analytical method for the sensitive determination of 69 analytes in bovine milk by liquid chromatography electrospray ionisation–tandem mass spectrometry. Antimicrobial, anabolic hormone, lactone, β-agonist, mycotoxin and pesticide residues were analysed in 120 raw milk samples from different dairy farms in North Macedonia. Stable isotopically labelled internal standards were used to facilitate effective quantification of the analytes. The linear regression coefficients were higher than 0.99, the limits of detection ranged from 0.0036 to 47.94 μg/L, and the limits of quantification ranged from 0.053 to 59.43 μg/L. The decision limit values ranged from 0.062 to 211.32 μg/L and the detection capability from 0.080 to 233.71 μg/L. Average recoveries of the analytes spiked in raw milk were in the range of 70.83% to 109%, intra-day coefficient of variation (CV) values from 2.41% to 22.29%, and inter-day CV values from 3.48% to 23.91%. The method was successfully applied in the testing of bovine milk samples. In five samples residues were detected. They were sulfadimethoxine (in two samples), enrofloxacin, tetracycline and oxytetracycline and were at concentrations below the EU maximum residue limit. The method is useful for routine testing for this group of chemical hazards in bovine milk.

Objectives: The objective of this study was to evaluate the persistence of oxytetracycline (OTC) residue in common fish species (Catla, Rui, Mrigal, and Pangas) available in local fish markets and the corresponding transport water of the Mymensingh region. Materials and Methods: Live fish and corresponding transport water samples were analyzed by thin layer chromatography (TLC) and high-performance liquid chromatography for qualitative and quantitative detection of OTC residue, respectively. A total of 240 fish samples and 60 water samples were randomly collected from three local fish markets during the summer and winter seasons. Results: OTC residues were detected in 18 samples (13 fish and 5 water samples) in the summer and 8 samples (only fish samples) in the winter. The overall percentage of antibiotic residue positive in fish samples was 5.42%, and in water samples, it was 8.33%. In fish, OTC concentrations of TLC-positive samples ranged from 34.7 to 56.85 parts per billion (ppb) in Catla, 23.45–35.37 in Rui, 11.02–26.80 in Mrigal, and 10.80–77.55 in Pangas during summer. The concentrations were 18.5 ppb in Catla, 15–16.09 in Rui, 10–14.63 in Mrigal, and 21.02–40.11 in Pangas during the win¬ter season. On the other hand, the range of OTC concentrations of TLC-positive samples for water was 12.9–59.18 ppb during summer and below the detection level during winter. The highest prevalence of antibiotic residues among fish samples was found in Pangas (16.67%). The highest percentage of samples (15% in the fish sample and 30% in the water sample) found to be positive were collected from Mechua Bazar. The comparison between the summer and winter seasons showed that the percentage of positive antibiotic residue in the summer season (10.38% for fish and 16.67% for water) is higher than that of the winter season (6.67% for fish samples only). This variation indicates that fish transporters use more antibiotics during the summer than in the winter season. The difference between the means of fish species and water samples was not statistically significant (p > 0.05). In addition, no samples exceeded the maximum residue limits (MRL) of OTC (100 ppb) in fish set by the European Commission. Conclusion: Although the concentrations of antibiotic residues in fish edible tissues are below MRL values, the presence of antibiotic residues in transported water may lead to the development of antimicrobial resistance bacteria that are detrimental to humans, animals, and aquatic animals. [J Adv Vet Anim Res 2022; 9(1.000): 104-112]