The influence of 7-OH methotrexate metabolite on clinical relevance of methotrexate determination.

BACKGROUND: A modified high performance liquid chromatographic (HPLC) method has been developed for the simultaneous determination of methotrexate (MTX) and its main metabolite 7-hydroxymethotrexate (7-OHMTX) and compared to the immunochemical fluorescence polarization immunoassay (FPIA2) determination of methotrexate. METHODS: Methotrexate was determined by HPLC with UV detection at 303 nm after precipitation of proteins with trichloroacetic acid. Fluorescence polarization immunoassays (FPIA2) of methotrexate were performed on the TDx FLx Immunoassay Analyzer. RESULTS: Our data indicate good correlation between methotrexate levels > 1 micromol/L determined by HPLC and FPIA2. (r = 0.94, Spearman correlation coefficient). However, concentrations of methotrexate < 1 micromol/L measured by fluorescence polarization immunoassay were overestimated. CONCLUSIONS: The concentration of MTX < 1 micromol/L are overestimated due to the cross reactivity with metabolites 7-OHMTX and 2,4-diamino-N10-methylpteroic acid (DAMPA). The cross reaction may affect the therapy and lead to relapse in children with acute lymphoblastic leukemia.

Alterations in serum selenium levels and their relation to troponin I in acute myocardial infarction.

Selenium (Se) is an essential trace element with antioxidant function. The aim of the present study was to estimate the alterations of Se serum level during the acute phase of myocardial infarction and its relation to biomarkers of myocardial necrosis. Serum Se levels were measured at admission and after 24 h in 60 consecutive patients with acute coronary syndrome (both with and without ST elevation). Troponin I (TnI) was assessed at admission and then twice daily for 3 days; patients with normal levels were excluded. Fifty-five patients with acute MI (positive TnI) were included into the analysis. During the first day of hospitalization, patients received standard therapy, including acetylsalicylic acid, clopidogrel, and heparin or enoxaparin; all underwent urgent coronary angiography and percutaneous intervention, when appropriate. Mean Se levels at baseline and 24 h later were comparable (67.1 ± 2.1 vs. 67.2 ± 1.8 µg/L, ns). Linear regression has shown significant correlation between baseline Se levels and peak TnI (y = 3.4x - 116, r (2) = 0.13, P = 0.008). Positive correlation was found also between the peak TnI and the difference from baseline to 24 h (y = 2.2x + 115, r (2) = 0.08, P = 0.04). Moreover, close negative correlation was observed between baseline Se levels and the difference from baseline to 24 h (y = -0.9x + 62.7, r (2) = 0.55, P<0.001). Our results have shown marked individual changes in Se levels during the acute phase of MI as well as correlation between Se levels and peak TnI. These results suggest that alterations in serum Se may be related to the extent of myocardial infarction.

Intravitreal carboplatin concentration and area under concentration versus time curve after intravitreal and periocular delivery.

PURPOSE: To determine platinum (Pt) concentrations and area under the concentration versus time curve (AUC) of the vitreous humor after periocular or transcorneal intravitreal administration of carboplatin in rabbits. METHODS: Eighteen albino rabbits were included in an in vivo experiment. Each animal received a single dose of either 30 mg of carboplatin by periocular injection (POI30 group: n = 6) or 15 mg by periocular injection (PI15 group: n = 6), or 0.05 mg by transcorneal intravitreal injection (TII group: n = 6), respectively, into the right eye. Vitreous humor from the right eyes and plasma samples were collected post dose at 1, 2, 6, 24, 48, 168, and 336 hours or 448 hours, respectively. Flameless atomic absorption spectroscopy was employed to analyze total platinum concentrations in blood and vitreous humor. AUC was calculated using the trapezoidal rule. RESULTS: Pt concentration was mostly < 1 mg/L (0-3.15 mg/L) in the vitreous humor samples and > or = 2 mg/L (2.33-7.3 mg/L) in the blood samples 1 hour after administration in POI groups. Markedly higher Pt concentrations were found 1 hour after intravitreal (TII) administration (10.285-66.759 mg/L) and decreased below 1 mg/L no less than 168 hours after administration. The mean AUC for Pt in vitreous humor was significantly lower (p = 0.0001) after both POI30 and P0I15 administration compared to TII route (8.955 +/- 2.464 mg/L/min). CONCLUSIONS: These findings proved that intravitreal carboplatin delivery enables the achievement of relatively stable concentrations and AUC of platinum in the rabbit vitreous humor. This moreover suggests that transcorneal intravitreal delivery of carboplatin aiming to treat retinoblastoma vitreous seeding is a promising mode of chemotherapy.

An adsorptive transfer technique coupled with brdicka reaction to reveal the importance of metallothionein in chemotherapy with platinum based cytostatics.

The drugs based on platinum metals represent one of the oldest, but also one of the most effective groups of chemotherapeutic agents. Thanks to many clinical studies it is known that resistance of tumor cells to drugs is a frequent cause of chemotherapy failure. With regard to platinum based drugs, multidrug resistance can also be connected with increased expression of low-molecular weight protein metallothionein (MT). This study aimed at investigating the interactions of MT with cisplatin or carboplatin, using the adsorptive transfer technique coupled with differential pulse voltammetry Brdicka reaction (AdTS DPV Brdicka reaction), and a comparison of in vitro results with results obtained in vivo. The results obtained from the in vitro study show a strong affinity between platinum based drugs and MT. Further, we analyzed extracts of neuroblastoma cell lines treated with cisplatin or carboplatin. It is clear that neuroblastoma UKF-NB-4 cisplatin-resistant and cisplatin-sensitive cell lines unlikely respond to the presence of the platinum-based cytostatics cisplatin and carboplatin. Finally, we determined the level of MT in samples from rabbits treated with carboplatin and patients with retinoblastoma treated with the same drug.

Utilizing of Adsorptive Transfer Stripping Technique Brdicka Reaction for Determination of Metallothioneins Level in Melanoma Cells, Blood Serum and Tissues.

In the paper we utilized the adsorptive transfer stripping differential pulse voltammetry Brdicka reaction for the determination of metallothioneins (MT) in melanoma cells, animal melanoma tissues (MeLiM miniature pig) and blood serum of patients with malignant melanoma. Primarily we attempted to investigate the influence of dilution of real sample on MT electrochemical response. Dilution of samples of 1 000 times was chosen the most suitable for determination of MT level in biological samples. Then we quantified the MT level in the melanoma cells, the animal melanoma tissues and the blood serum samples. The MT content in the cells varied within the range from 4.2 to 11.2 µM. At animal melanoma tissues (melanomas localized on abdomen, back limb and dorsum) the highest content of MT was determined in the tumour sampled on the back of the animal and was nearly 500 µg of MTs per gram of a tissue. We also quantified content of MT in metastases, which was found in liver, spleen and lymph nodes. Moreover the average MT level in the blood serum samples from patients with melanoma was 3.0 ± 0.8 µM. MT levels determined at melanoma samples were significantly (p < 0.05) higher compared to control ones at cells, tissues and blood serum.

Anti-vimentin antibodies and neuron-specific enolase in children with neurofibromatosis type-1.

OBJECTIVES: The aim of the study was to investigate the relationship of serum levels of neuron-specific enolase, anti-vimentin IgG, and anti-vimentin IgM antibodies in patients with neurofibromatosis type 1 and associated tumors (optic glioma, and plexiform neurofibroma). METHODS: Measurement of neuron-specific enolase and anti-vimentin antibodies were performed in 131 children and adolescents (67 males, mean age 10 years, range 4-19 years; 64 females, mean age 11 years, range 1-20 years) with three different forms of neurofibromatosis type 1 and in control group of 40 individuals (20 males, mean age 9 years, range 1-19 years and 20 females, mean age 12 years, range 3-18 years). RESULTS: Anti-vimentin IgG, IgM antibodies and NSE showed similar ability to distinguish between neurofibromatosis type 1 and tumors associated with neurofibromatosis type 1. (AUC=0.57, AUC=0.52 and AUC=0.59 respectively). NSE showed better diagnostic efficiency (AUC=0.68) than the anti-vimentin IgG and anti-vimentin IgM. (AUC=0.63 and AUC=0.56 respectively). Anti-vimentin IgG and IgM antibodies showed higher sensitivity (87.5% and 87.2%) at the cut off value than the NSE (54%). On the contrary, NSE showed higher specificity at the cut off value than both the anti-vimentin IgG and IgM (71% vs. 22.5% and 16% respectively). CONCLUSIONS: Anti-vimentin IgG and IgM and neuron-specific enolase are relevant markers in investigation of the patients with neurofibromatosis type 1 and associated tumors.

Blood metallothionein, neuron specific enolase, and protein S100B in patients with traumatic brain injury.

OBJECTIVES: The aim of this study was to evaluate the correlation of neuron specific enolase (NSE), protein S100B and time-profile of Glasgow Coma Score (GCS) development with metallothionein (MT) blood levels in patients with traumatic brain injury (TBI) during 10 days of hospitalization. Patients were divided into 2 groups with respect to NSE and S100B levels - with (group I) and without (group II) GCS improvement. METHODS: Serum NSE and S100B concentrations were measured by immunochemical methods; serum metallothionein concentration by electrochemical technique. Cortical biopsies were investigated immunohistochemically and by electron microscope. A cDNA microarray containing 700 gene probes was used to study the changes in gene expression in the ipsilateral cortex. RESULTS: Values of MT in the blood of group I showed a non-significant decrease compared to group II during 1-3 days after admission. There was an increase of MT during 4-8 days in comparison with values of 1-3 days. The highest value of MT during hospitalization was found in a patient with diffuse axonal injury (group II). The data of cDNA microarray suggested an increase in expression of gene transcripts for oxygen free radical scavenger proteins corresponding with the increase of MT during 4-8 days in both groups. CONCLUSIONS: The experimental data indicate that monitoring the content of MT in patients with trauma brain injury would be a suitable approach to evaluate the degree of injury or duration of prolonging unconsciousness, particularly in diagnosis of diffuse axonal injury.

NT-proBNP and BNP values in cardiac patients with different degree of left ventricular systolic dysfunction.

We investigated the performance of brain natriuretic peptides (BNP and NT-proBNP) in detecting various degrees of left ventricular systolic dysfunction. The NT-proBNP assay (Roche) and the BNP assay (Bayer Shionoria) were performed in 46 patients (mean age 50 years; range 20-79 years) with various types of heart disease (chronic heart failure due to coronary artery disease, cardiomyopathy, acquired valve disease, congenital heart diseases) and different impairment of left ventricular systolic dysfunction was assessed by echocardiography. Patients were divided into four groups according to the left ventricular ejection fraction (LVEF) correlated with clinical severity. Significant differences in medians of NT-proBNP and BNP values between all groups were determined (P= 0.0161 for NT-proBNP and P=0.0180 for BNP). For identifying patients with severe systolic dysfunction (LVEF<40%), receiver operating characteristic (ROC) analysis for both BNP and NT-proBNP was performed. The diagnostic performances expressed as areas under the curve were of 0.69 for NT-proBNP (cut off value 367 pg/ml) and 0.60 for BNP (cut off value 172 pg/ml). However, the BNP showed higher sensitivity (85 % vs. 63 %) and a higher positive predictive value (69 % vs 55 %) than the NT-proBNP. The negative predictive values of BNP and NT-proBNP were similar (70 % and 71 % respectively). Brain natriuretic peptides are promising markers for the diagnosis of severe left ventricular systolic dysfunction.

The relevance of brain natriuretic peptides investigation in various cardiovascular diseases.

BACKGROUND: Brain natriuretic peptides are relevant markers of heart impairment. AIM: We investigated the relevance of investiging brain natriuretic peptides (NT-proBNP, BNP) in monitoring different types of cardiovascular disease (chronic heart failure due to coronary artery disease, cardiomyopathy, acquired valve disease, congenital heart diseases). METHODS: The NT-proBNP assay (Roche) was performed on 280 patients (mean age 49 years; range 20-89 years) and 48 healthy controls (mean age 43 years; range 13-65 years) and BNP assay (Bayer Shionoria) was performed in a subgroup of 42 patients (mean age 50 years; range 20-79 years). Patients were divided into four groups characterized by severity of heart failure according to the New York Heart Association classification. RESULTS: NT-proBNP concentrations differed in patients with cardiovascular diseases from controls (median 371 ng/l versus 41.5 ng/l, p < 0.0001). The cut off value of NT-proBNP determined in 280 patients with cardiovascular diseases was at 130 ng/l (AUC-area under curve = 0.93; sensitivity 98 %; specificity 79 %). Comparison of NT-proBNP and BNP values in patients showed significant correlation (r = 0.93; p < 0.0001). NT-proBNP showed significant differences between groups. CONCLUSIONS: Measurement of brain natriuretic peptides is useful and relevant in various types of heart diseases including congenital.

Matrix metalloproteinases and their function in myocardium.

A significant number of myocardial diseases are accompanied by increased synthesis and degradation of the extracellular matrix (ECM) as well as by changed maturation and incorporation of ECM components. Important groups of enzymes responsible for both normal and pathological processes in ECM remodeling are matrix metaloproteinases (MMPs). These enzymes share a relatively conserved structure with a number of identifiable modules linked to their specific functions. The most important function of MMPs is the ability to cleave various ECM components; including such rigid molecules as fibrillar collagen molecules. The amount and activity of MMPs in cardiac tissue are regulated by a range of activating and inhibiting processes. Although MMPs play multifarious roles in many myocardial diseases, here we have focused on their function in ischemic cardiac tissue, dilated cardiomyopathy and hypertrophied cardiac tissue. The inhibition of MMPs by means of synthetic inhibitors seems to be a promising strategy in cardiac disease treatment. Their effects on diseased cardiac tissue have been successfully tested in several experimental studies.

Using of electrochemical methods for studying of metallothionein content in the human blood serum of a patient poisoned by lead and treated by platinum.

Metallothioneins belong to the group of intracellular, high molecular and cysteine-rich proteins whose content increase with increasing concentration of a heavy metal. Here we applied the adsorptive transfer stripping differential pulse voltammetry Brdicka reaction for the determination of metallothionein in human blood serum of patient poisoned by lead and/or treated by platinum. The increased metallothionein concentrations in both cases were observed.

Retinal toxicity after repeated intravitreal carboplatin injection into rabbit eyes.

BACKGROUND: The aim of this study was to assess retinal toxicity in a rabbit model after carboplatin delivered as repeated transcorneal intravitreal injection, in order to determine the highest possible safe dose for use in human retinoblastoma "seeding" tumor chemotherapy. METHODS AND RESULTS: We used six albino rabbits in an in vivo experiment and injected 0.008 mg of carboplatin intravitreally (iv) 4 times at two-week intervals. 0.08 mL saline was injected into the left eye. We recorded electroretinograms (ERGs) before the first carboplatin injection and after the fourth injection. Platinum concentration was measured 1 h after the fifth additional injection. We found reduced dark-adapted b-wave amplitudes and, light-adapted b-wave and a-wave amplitudes. The differences between right and left eyes was significant but we found no histopathologic retinal changes. CONCLUSIONS: 0.008 mg of carboplatin is probably the highest possible safe dose for the treatment of retinoblastoma patients. Questionable is direct extrapolation of retinal toxicity from the rabbit eye model to the human eye.

Serum metallothionein in newly diagnosed patients with childhood solid tumours.

Tumour markers are substances produced by malignant cells or by the organism as a response to cancer development. Determination of their levels can, therefore, be used to monitor the risk, presence and prognosis of a cancer disease or to monitor the therapeutic response or early detection of residual disease. Time-consuming imaging methods, examination of cerebrospinal fluid or tumour tissue and assays for hormones and tumour markers have been used for cancer diagnosis. However, no specific marker for diagnosis of childhood solid tumours has been discovered yet. In this study, metallothionein (MT) was evaluated as a prospective marker for such diseases. Serum metallothionein levels of patients with childhood solid tumours were determined using differential pulse voltammetry - Brdicka reaction. A more than 5-fold increase in the amount of metallothionein was found in sera of patients suffering from cancer disease, compared with those in sera of healthy donors. The average metallothionein level in the sera of healthy volunteers was 0.5 ± 0.2 µmol · dm⁻³ and was significantly different (p<0.05, determined using the Schefe test) from the average MT level found in serum samples of patients suffering from childhood solid tumours (3.4 ± 0.8 µmol · dm⁻³). Results found in this work indicate that the MT level in blood serum can be considered as a promising marker for diagnostics, prognosis and estimation of therapy efficiency of childhood tumours.

Fluvastatin in the first-line therapy of acute coronary syndrome: results of the multicenter, randomized, double-blind, placebo-controlled trial (the FACS-trial).

BACKGROUND: Statins have been proved to be effective in reduction of mortality and morbidity when started in the early secondary prevention in stabilized patients after acute coronary syndrome (ACS). The safety and efficacy of statin administration directly in the first-line therapy in unstable ACS patients is not clear. The aim of our study was, therefore, to assess the effect of statin treatment initiated immediately at hospital admission of patients with ACS. METHODS: The trial was stopped prematurely after enrollment of one hundred and fifty-six patients with ACS that were randomized at admission to fluvastatin 80 mg (N = 78) or placebo (N = 78). Study medication was administered immediately after randomization and then once daily for 30 days; all patients were then encouraged to continue in open-label statin therapy and at the end of one-year follow-up 75% in the fluvastatin group and 78% in the placebo group were on statin therapy. RESULTS: We did not demonstrate any difference between groups in the level of C-reactive protein, interleukin 6, and pregnancy-associated plasma protein A on Day 2 and Day 30 (primary endpoint). Fluvastatin-therapy, however, significantly reduced one-year occurrence of major adverse cardiovascular events (11.5% vs. 24.4%, odds ratio (OR) 0.40, 95% CI 0.17-0.95, P = 0.038). This difference was caused mainly by reduction of recurrent symptomatic ischemia (7.7% vs. 20.5%, OR 0.32, 95% CI 0.12-0.88, P = 0.037). CONCLUSIONS: This study failed to prove the effect of fluvastatin given as first-line therapy of ACS on serum markers of inflammation and plaque instability. Fluvastatin therapy was, however, safe and it may reduce cardiovascular event rate that supports immediate use of a statin in patients admitted for ACS. TRIAL REGISTRATION: NCT00171275.

Immediate effect of fluvastatin on lipid levels in acute coronary syndrome.

It is widely assumed that acute benefit of statin therapy is mediated especially by non-lipid effects. The immediate influence of statins on lipid levels in patients with acute coronary syndrome (ACS) is, however, not clear. A total of 64 consecutive patients with ACS were randomized at admission to fluvastatin 80 mg (Group 1, N = 32) or standard therapy without statin (Group 2, N = 32). The levels of total cholesterol (TC), low-density-lipoprotein cholesterol (LDL-C), high-density-lipoprotein cholesterol (HDL-C), and triglycerides (TG) were examined at admission and after 24 h. Baseline characteristics were comparable in both groups. In Group 1, fluvastatin significantly decreased the levels of TC by 14.5%, LDL-C by 17.2%, and HDL-C by 10.0% (P < 0.001); TG were not influenced. In Group 2 only marginal reductions in TC (by 4.1%, P = 0.03) and HDL-C (by 7.5%, P < 0.01) were detected; the levels of LDL-C and TG were not changed. As compared with Group 2, in Group 1 the final levels of TC (P = 0.02) and LDL-C (P = 0.01) were significantly lower. Fluvastatin therapy, when started at admission in patients with ACS, significantly reduces TC and LDL-C already after 24 h. We suggest that the lipid-lowering effect of statins in the therapy of ACS is probably as prompt as non-lipid effects.