Markéta Kašparová

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.

HPLC method for simultaneous determination of retinoids and tocopherols in human serum for monitoring of anticancer therapy

A simple and rapid HPLC method requiring small volumes (250 microL) of human serum after C18 SPE sample preparation was developed using monolithic technology for simultaneous determination of all-trans-retinoic acid, 13-cis-retinoic acid, retinol, gamma- and alpha-tocopherol. The monolithic column, Chromolith Performance RP-18e (100x4.6 mm), was operated at ambient temperature. The mobile phase consisted of a mixture of acetonitrile (ACN) and 1% ammonium acetate in water (AMC) at pH 7.0. The mobile phase started at 98:2 (v/v) ACN/AMC (column pre-treatment) at a flow rate of 2 mL/min, then changed to 95:5 (v/v) ACN/AMC for 4 min at a flow rate of 1.5 mL/min and a further 3 min at a flow rate of 3.2 mL/min. Detection and identification were performed using a photodiode array detector. Retinol, 13-cis- and all-trans-retinoic acid were monitored at 325 nm. Both alpha- and gamma-tocopherol were detected at 295 nm. The total analysis time was 7.2 min. Tocol (synthesized tocopherol, not occurring in humans) was used as internal standard. The method was linear in the range of 0.125-10.00 micromol/L for all-trans-retinoic acid, 0.125-5.00 micromol/L for 13-cis-retinoic acid, 0.25-10.00 micromol/L for retinol, 0.5-50.00 micromol/L for gamma-tocopherol, and 0.5-50.00 micromol/L for alpha-tocopherol. The present method may be useful for monitoring of retinoids and tocopherols in clinical studies.

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.

Determination of neopterin, kynurenine, tryptophan and creatinine in human serum by high throuput HPLC.

A new HPLC method for simultaneous determination of neopterin, creatinine, kynurenine and tryptophan in human serum was developed and validated. Monolithic stationary phases technology (two monolithic columns RP-18e were connected with guard monolithic cartridge 4.6 mm × 50 mm+3.0 mm × 100 mm and 4.6 × 10 mm) and special auto sampler for micro titration plates (samples are storage in dark cooled place protected against evaporation) were combined with easy sample preparation step. As mobile phase 15 mmol/L phosphate buffer at pH 4.50 was used. Neopterin and tryptophan were detected using fluorescent detection and kynurenine and creatinine were detected by diode-array detection. This method may be suitable for large sequences of samples in clinical research and 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.

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.

Separation of Vitamins Retinol Acetate, Ergocalciferol, or Cholecalciferol and Tocopherol Acetate Using Sequential Injection Chromatography

A novel simple method for separation of vitamins A-acetate (all-trans retinol acetate), D2 (ergocalciferol), or D3 (cholecalciferol) and E-acetate (tocopherol acetate) using short monolithic column in the sequential injection chromatography system is described. Separation was carried out using FIAlab® 3000 system under following conditions: Onyx™ Monolithic C18 column (25 × 4.6 mm), mobile phase acetonitrile:methanol:H2O 20:20:1 (v/v/v)), flow rate 0.9 mL min−1, detection at 265 nm (D), 290 nm (E), and 325 nm (A). The method was validated with respect to peak asymmetry, resolution, number of theoretical plates, repeatability, linearity, precision, and accuracy. Analysis time was 5.5 min.

Intestinal permeability, vitamin A absorption and serum alpha-tocopherol during therapy with gefitinib.

Abstract Measurement of intestinal permeability represents one of the potential methods of noninvasive laboratory assessment of gastrointestinal toxicity of anticancer therapy. We have assessed intestinal permeability (by measuring absorption of lactulose, mannitol, and xylose), vitamin A absorption and serum alpha-tocopherol in patients with non-small cell lung carcinoma or head and neck carcinomas treated with gefitinib. Lactulose, mannitol and xylose were determined by capillary gas chromatography, and retinol, alpha-tocopherol, retinyl stearate and retinyl palmitate were determined by high-performance liquid chromatography. Compared to healthy controls, patients had significantly increased lactulose/mannitol ratio and lower postprandial retinyl palmitate and retinyl stearate concentrations. Compared with pre-treatment values, xylose absorption was decreased and lactulose/mannitol and lactulose/xylose ratios were increased during the therapy. A significant decrease of serum alpha-tocopherol was evident throughout the course of therapy. In contrast, only minor alterations of vitamin A absorption were observed. In conclusion, an alteration in intestinal permeability reflected in increased lactulose/mannitol and lactulose/xylose ratios was observed during gefitinib therapy. Potential association between decreased serum alpha-tocopherol concentrations and the toxicity of gefitinib therapy should be further investigated.

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.