Background: Scientific studies point to a significant global vitamin D deficiency. The recommended dose of vitamin D for the adult population in Central Europe is 800–2000 IU/day. The aim of our study was to determine whether doses of 1000 IU or 2000 IU of vitamin D₃ are adequate to achieve the sufficiency reference values of [25(OH)D]. Methods: Seventy-two healthy volunteers, average age twenty-two, took part in the study. The study was conducted from October to March in order to eliminate intra-dermal vitamin D production. Vitamin D₃ in an oleaginous mixture was used. The participants used either 1000 IU or 2000 IU/daily for two 60-day periods with a 30-day break. Results: The dose of 1000 IU, taken for 60 days, increased vitamin D levels relatively little. Furthermore, serum vitamin D levels decreased in the 30 days following the cessation of supplementation. Taking 2000 IU daily led to a sharp increase in serum levels which plateaued 30 days after the subjects stopped using vitamin D₃ drops. Conclusions: Both doses, taken daily, can help maintain adequate vitamin D levels during the winter months. A daily dose of 2000 IU, however, maintained the desired levels of vitamin D for a longer period.

Background: The medication used to treat benign prostate hyperplasia (BPH), a common condition in men over 50 years of age, can alter the levels of biomarkers used in prostate cancer detection. Commonly used medications for BPH include alpha‐blockers, 5‐alpha reductase inhibitors (5‐ARIs), and muscarinic antagonists. We studied the impact of these drugs on total prostate‐specific antigen (tPSA), free PSA (fPSA), [−2]proPSA, fPSA/tPSA ratio, and the Prostate Health Index (PHI), as well as novel potential biomarkers in the form of glycan composition of fPSA.Patients and Methods: Serum samples were collected from 564 males with BPH, with a mean age of 68.5 years. The samples were used to measure levels of tPSA, fPSA, and [−2]proPSA. The fPSA/tPSA and PHI were then calculated. The glycan composition of fPSA was analyzed using lectin‐based glycoprofiling. Pharmacotherapy data was collected from the patients' medical records.Results: Alpha‐blocker monotherapy was associated with higher fPSA and fPSA/tPSA ratio, and decreased PHI. Levels of tPSA were not impacted. Alpha‐blocker and 5‐ARI dual therapy was associated with reduced levels of fPSA, [−2]proPSA, and PHI. Therapy combining alpha‐blockers and antimuscarinic agents did not significantly influence biomarker levels apart from an increase in a Maackia amurensis lectin‐recognized glycan originating in fPSA.Conclusion: BPH pharmacotherapy notably affects prostate cancer biomarkers. Recognizing the impact of pharmacotherapy is crucial for achieving an accurate diagnosis of prostate cancer and for planning treatment.

Accurate assessment of vitamin D metabolism is crucial not only for the diagnosis and treatment of disorders related to bone health and calcium homeostasis but also for understanding its broader physiological roles in immunity, cellular differentiation, cardiovascular regulation, and endocrine function. Although 25‐hydroxyvitamin D ₃ (25(OH)D ₃ ) is routinely measured in clinical practice, the low‐abundance metabolite 24,25‐dihydroxyvitamin D ₃ (24,25(OH) ₂ D ₃ ) provides complementary insight into vitamin D catabolism. Reduced or undetectable 24,25(OH) ₂ D ₃ levels may signal impaired CYP24A1 function or insufficient conversion of 25(OH)D ₃ to maintain appropriate intracellular concentrations of biologically active 1,25(OH) ₂ D ₃ . However, quantification of 24,25(OH) ₂ D ₃ remains analytically challenging and requires highly selective and sensitive liquid chromatography–tandem mass spectrometry (LC–MS/MS) methodology. In‐house developed LC–MS/MS approaches are being increasingly employed, offering greater specificity and sensitivity over conventional immunoassays, allowing accurate detection of low‐abundance vitamin D metabolites. Additionally, when interpreted together with 25(OH)D ₃ , 24,25(OH) ₂ D ₃ allows the calculation of the vitamin D metabolite ratio (VMR), which offers a more accurate assessment of vitamin D sufficiency and catabolism. The aim of this study was to develop and validate a robust LC–MS/MS method using dynamic multiple reaction monitoring (dMRM) and sample derivatization for quantifying 24,25(OH) ₂ D ₃ in human serum. The method described was evaluated according to EMA guidelines and DEQAS controls. The matrix effect was minimized through lipid‐removal filtration. The assay demonstrated excellent linearity ( R ² = 0.9982), intra‐ and inter‐assay precision below 14%, and LOQ of 0.64 ng/mL. Recovery from DEQAS samples ranged from 80% to 118%, with a matrix‐induced ion enhancement of ∼17%. Additionally, 4‐phenyl‐1,2,4‐triazoline‐3,5‐dione (PTAD) derivatization enhanced the sensitivity 100‐fold. This highly sensitive LC–MS/MS method is suitable for clinical and research laboratories equipped with an electrospray ionization (ESI) source. Precise quantification of 24,25(OH) ₂ D ₃ can complement routine 25(OH)D ₃ analysis, support VMR determination, and serve as a reliable biomarker for disorders associated with altered vitamin D metabolism.