Jiří Plíšek

Intima-media thickness, myocardial perfusion and laboratory risk factors of atherosclerosis in patients with breast cancer treated with anthracycline-based chemotherapy

An increased incidence of complications of atherosclerosis has been noted in cancer survivors. The aim of the present study was to evaluate, in patients with breast carcinoma, the effect of antracycline-based chemotherapy on carotid intima-media thickness (IMT), myocardial perfusion, assessed by single-photon emission tomography (SPECT) and laboratory parameters associated with the risk of atherosclerosis. Thirty-six patients with breast cancer were evaluated before and after anthracycline-based chemotherapy. Retinol, alpha-tocopherol, glycosylated hemoglobin and urinary neopterin were measured by high-performance liquid chromatography. Peripheral blood cell count, D-dimers, fibrinogen, antithrombin, glucose, magnesium, creatinine, uric acid, albumin, C-reactive protein, lipoprotein (a), cholesterol, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, triglycerides, homocysteine, urinary albumin and N-acetyl-beta-d-glucosaminidase (NAG) were determined with routine methods. No significant differences were observed between patients and 16 controls. Compared to the measurement before the start of therapy, peripheral blood leukocyte and platelet count, hemoglobin, creatinine, HDL cholesterol, retinol, albumin, urinary albumin and NAG decreased, and total cholesterol, LDL cholesterol, triglycerides, neopterin and mean IMT increased significantly after the treatment. Of the 36 patients who had SPECT after treatment, perfusion defects were noted only in two cases, including the patient who had perfusion defects at baseline examination and a patient who did not have a baseline SPECT. In conclusion, a significant increase in carotid IMT, total cholesterol, LDL cholesterol, triglycerides and urinary neopterin and a decrease of peripheral blood leukocyte and platelet counts, hemoglobin, creatinine, HDL cholesterol, retinol, albumin and NAG were observed after the treatment.

Rapid sample preparation procedure for determination of retinol and α-tocopherol in human breast milk.

The liposoluble vitamins (retinol and α-tocopherol) concentration in human breast milk is of a cardinal knowledge especially for nutrition of prematurely born. It enables the feeding optimization of these important micronutrients for preterm infants. The novel rapid liquid-liquid extraction procedure for human breast milk investigation was developed and validated according to FDA guidelines. The recovery of retinol was 82-90% measured at three concentration levels 1.0, 2.5 and 5.0 μmol/L, for α-tocopherol 92-109% at concentration levels 2.5, 5.0 and 10.0 μmol/L. The repeatability of extraction procedure expressed as relative standard deviation was 3.26% for retinol and 4.79% for α-tocopherol. Developed extraction procedure was applied on 120 human breast milk samples. The separation of vitamins was completed using advantages of a monolithic column which accomplished demands of acceleration made by modern bio-analytical HPLC methodology. The analytes of interest were detected by diode-array detector at wavelengths 325 nm for retinol and 290 nm for α-tocopherol.

Comparison of a new high‐resolution monolithic column with core‐shell and fully porous columns for the analysis of retinol and α‐tocopherol in human serum and breast milk by ultra‐high‐performance liquid chromatography

The reduction of analysis time, cost, and improvement of separation efficiency are the main requirements in the development of high-throughput assay methods in bioanalysis. It can be achieved either by ultra-high-performance liquid chromatography (UHPLC) using stationary phases with small particles (<2 μm) at high back pressures or by using opposite direction--monolithic stationary phases with low back pressures. The application of new types of monolithic stationary phases for UHPLC is a novel idea combining these two different paths. The aim of this work was to test the recently introduced second-generation of monolithic column Chromolith® HighResolution for UHPLC analysis of liposoluble vitamins in comparison with core-shell and fully porous sub-2 μm columns with different particle sizes, column lengths, and shapes. The separation efficiency, peak shape, resolution, time of analysis, consumption of mobile phase, and lifetime of columns were calculated and compared. The main purpose of the study was to find a new, not only economical option of separation of liposoluble vitamins for routine practice.

Application of core–shell technology for determination of retinol and alpha-tocopherol in breast milk

Breast milk is a main source of fat-soluble vitamins for newborns and it is needful to monitor the nutritional status prior to its application. In this work a novel, high-throughput and low-cost method for monitoring of retinol and alpha-tocopherol in breast milk was developed, validated and compared with reference method using monolithic column. For this purpose five various porous shell and monolithic columns were tested on the basis of relationship between HETP and linear mobile phase velocity, analysis time and consumption of solvents. Finally the core-shell analytical column Kinetex C18 (2.6 μm, 100 Å, 100×4.6 mm) was chosen as the best and optimal values of flow rate, injection volume and temperature of analysis were established. The detection of retinol and alpha-tocopherol was carried out at 325 and 295 nm, respectively by diode array detector. The LOD 0.004 μmol/L and 0.078 μmol/L, the LOQ 0.012 μmol/L and 0.182 μmol/L for retinol and alpha-tocopherol, respectively were calculated. The validation data showed good linearity, repeatability of retention time with RSD 0.22% and 0.12%, repeatability of peak area with RSD 6.94% and 1.75%, recovery 114.1-116.3% and 99.0-108.6% for retinol and alpha-tocopherol, respectively. Moreover, the newly developed method substantially decreased the solvent consumption by about 263 mL per 100 samples with the total time of analysis 1.75 min in comparison with analysis time 1.80 of the reference method.

New approach for the clinical monitoring of 25-hydroxyvitamin D3 and 25-hydroxyvitamin D2 by ultra high performance liquid chromatography with MS/MS based on the standard reference material 972.

Biomarkers, 25-hydroxyvitamin D3 and 25-hydroxyvitamin D2 , are important indicators of the vitamin D general status and are monitored in several pathophysiological disorders, such as osteoporosis, diabetes, heart disease, etc. A novel ultra-HPLC with MS/MS methodology for the analysis of 25-hydroxyvitamin D derivatives coupled with a very simple and highly rapid sample preparation step was developed. Analytical parameters obtained showed linearity (R(2) ) above 0.999 for both vitamins with accuracies between 95.8 and 102%. The LODs were as low as 0.22 and 0.67 nmol/L for 25-hydroxyvitamin D3 and 25-hydroxyvitamin D2 , respectively. Intra-assay precision (%RSD) was lower than 4.5%, and inter-assay precision (%RSD) was lower than 6.5%. The feasibility of the developed methodology to be applied in clinical routine analysis has been proved by its application in blood samples from non-agenarian patients, patients with familial hypercholesterolemia and patients suffering from age-related macular degeneration.

Urinary Neopterin in Patients with Metastatic Colon Cancer Treated with Patupilone

Abstract Despite increased efficacy of regimens combining cytotoxic drugs and targeted agents, most patients with metastatic colorectal cancer will ultimately die of the disease. Only a limited number of drugs have reproducible activity in therapy of this tumor, and new active agents are urgently needed. Promising results in the therapy of metastatic colorectal cancer have been reported for patupilone, an epothilone analogue. Similarly to taxanes, the cytotoxic mechanism of epothilones involves the stabilization of microtubules. Increased serum or urinary concentrations of neopterin have been described in patients with tumors of different primary locations, including colorectal cancer. Neopterin concentrations were reported to increase during the administration of cytotoxic agents, including taxane-based chemotherapy. We have studied serum neopterin in patients with colorectal cancer before and during the therapy with patupilone. Urinary neopterin/creatinine concentrations were determined with highperformance liquid chromatography. Increased urinary neopterin concentrations were observed at baseline in the majority of the patients. In most patients, neopterin concentrations further increased during the therapy, and a significant increase of urinary neopterin was observed in patients with normal baseline neopterin concentrations. A trend of decreased survival was observed for patients with high initial neopterin concentration. In conclusion, urinary neopterin is increased in colorectal cancer patients presenting for second or higher line of treatment. An increase of urinary neopterin during patupilone therapy suggests an activation of immune response by this agent.

Miniaturisation of solid phase extraction method for determination of retinol, alpha- and gamma-tocopherol in human serum using new technologies

The aim of this study was to develop rapid and simple solid phase extraction (SPE) and HPLC methods for simultaneous determination of retinol, gamma- and alpha-tocopherol in human serum using a special auto sampler with micro titration plates. Separation of vitamins was performed at ambient temperature using monolithic column on a HPLC containing rack changer for micro titration plates. As the mobile phase methanol with flow rate 2.5 mL min−1 was used. The injection volume was 20 µL. Retinol was detected at 325 nm, gamma- and alpha-tocopherol were carried out at 295 nm, respectively. The total time of analysis was 1.8 minutes. Extraction method was developed using Spe-ed 96 C18, 100 mg/2 mL micro titration plates and SPE vacuum manifold. The consumption of the sample was 50 µL. Time of the analysis for 96 samples on one micro titration plate was 1.5 hour. In order to validate the developed method, precision, accuracy, linearity, detection and quantitation limits were evaluated. This method is suitable for rapid automated large-batch analysis of retinol, alpha- and gamma-tocopherol in small sample volumes of human serum.

Combination of ultracentrifugation and solid‐phase extraction with subsequent chromatographic analysis of α‐tocopherol in erythrocyte membranes

A novel and rapid sample pretreatment technique based on a combination of ultracentrifugation and solid-phase extraction for the determination of α-tocopherol in human erythrocyte membranes by high-performance liquid chromatography with ultraviolet detection is presented in this work. Red blood cell samples were ultracentrifuged (288 000 × g, 3 min, 4°C) in the presence of d-mannitol, 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid and calcium chloride. The α-tocopherol was then extracted from the erythrocyte membranes by solid-phase extraction with n-hexane in the presence of ascorbic acid. Tocopherol acetate was used as the internal standard. The extract was dissolved in methanol and separated on the monolithic column Chromolith Performance RP-18e (100 × 4.6 mm) using 100% methanol as the mobile phase. The absorbance of α-tocopherol was measured at a wavelength of 295 nm. The method was validated and showed sufficient accuracy and precision, ranging from 96.4 to 100.8% and from 4.5 to 6.3%, respectively. Moreover, the developed method was applied to the determination of erythrocyte α-tocopherol in real samples from patients. The combined ultracentrifugation and solid-phase extraction technique substantially decreased the time for the sample pretreatment step compared to liquid-liquid extraction and could be applicable for the quantitation of other analytes in erythrocyte membranes.

Urinary Neopterin, Serum Retinol, α-tocopherol and Homocysteine in Breast Cancer Patients During Treatment with Bevacizumab and Chemotherapy

Abstract Bevacizumab, monoclonal antibody targeting vascular endothelial growth factor, is effective in different tumors, including colorectal carcinoma, non-small cell lung cancer, renal cell carcinoma and breast cancer. Increased serum or urinary concentrations of neopterin, an indicator of systemic immune response, have been described in patients with tumors of different primary locations, and further increase has been observed during anticancer therapy. An increase of urinary neopterin has been described after administration of cytokines, cytotoxic chemotherapy, or external beam radiation, but less is known about the effects of targeted agents on systemic immune response. We have studied serum homocysteine, C-reactive protein, α-tocopherol and retinol, and urinary neopterin in patients with metastatic breast cancer treated with bevacizumab, taxane and carboplatin. Homocysteine and C-reactive protein were determined immunochemically. α-tocopherol, retinol and urinary neopterin were determined by high performance liquid chromatography. Homocysteine, C-reactive protein and urinary neopterin decreased, while retinol and α-tocopherol increased during the therapy. In conclusion, the treatment of patients with metastatic breast cancer with bevacizumab, taxane and carboplatin resulted in the suppression of systemic inflammatory and immune response. The suppression of systemic inflammatory and immune response was associated with an increase in serum vitamin concentrations.

Correlation of Peripheral Blood CD14+CD16+ Monocytes, Urinary Neopterin and the Risk Factors of Atherosclerosis in Patients with Breast Carcinoma

Abstract Monocytes/macrophages are thought to play a fundamental role in the development of vascular lesions in atherosclerosis. In the present study, we evaluated circulating CD14+CD16+ monocytes, laboratory parameters of the risk of atherosclerosis, including serum cholesterol, homocysteine and C-reactive protein, urinary neopterin, serum a-tocopherol and retinol along with carotid intima-media thickness in patients with breast carcinoma. A significant correlation was observed between the absolute numbers of CD14+CD16+ monocytes, serum HDL cholesterol and triglyceride concentrations. In conclusion, present data extend the observation of an association between peripheral blood CD14+CD16+ monocyte counts and lipid metabolism to cancer patients. No correlation of CD14+CD16+ monocyte counts with urinary neopterin concentrations was observed.