Noninvasive study of brain tumours metabolism using phosphorus-31 magnetic resonance spectroscopy.

Phosphorus-31 magnetic resonance spectroscopy (31P MRS) is currently not accepted as a diagnostic tool in the neuro-oncological practice, although it provides useful non-invasive information about biochemical processes ongoing in the intracranial tumours. This pilot study was aimed to present the diagnostic capability of the 31P MRS in brain tumour examination, even its application on clinical 1.5T MR scanner.Seven patients with brain tumorous lesions (four glioblastomas, one ependymoma, and two lung metastasis) underwent multivoxel in vivo 31P MRS performed on clinical 1.5 T MR scanner within measurement time of 20 minutes. Comparing two selected voxels, one in the tumour and the other one in the normal-appearing brain tissue, enabled to investigate their metabolic differences. Enhanced markers of membrane phospholipids synthesis (significantly increased phosphomonoesters ratios) than markers of their degradation (significantly decreased phosphodiesters ratios) manifested a higher cell proliferation ongoing in tumours. High energetic tumorous tissue demands leading to anaerobic metabolic turnover were present as a significant decline in phosphocreatine ratios and adenosine triphosphates. Intracellular pH evaluation showed a tumorous tendency to alkalize. 31P MRS enables the non-invasive metabolic characterization of intracranial tumours and thus appears to be a clinically useful method for the determination of ongoing tumour pathomechanisms (Fig. 2, Ref. 26). Keywords: brain tumour, 31P MRS, 1.5 Tesla; energetic metabolism.

Soluble receptor for advanced glycation end products in late-onset neonatal infection.

OBJECTIVES: To assess the plasma levels of sRAGE (soluble receptor for advanced glycation end products) in infected and non-infected preterm neonates and to compare their diagnostic values with standard infection biomarkers. BACKGROUND: RAGE activates pathways responsible for acute and chronic inflammation. The soluble type of this receptor, sRAGE, which acts as a decoy receptor, has been linked to the severity of sepsis and its outcome. METHODS: Prospective clinical study was carried out from January 2011 to August 2013. There were 33 neonates included according to their infection status and divided into subgroups as follows: infected (I), septic (S), non-infected controls (C). RESULTS: We found significantly lower values of sRAGE in the subgroup S (905.54±220.53 pg/mL; p < 0.028), while borderline values were higher in the subgroup I vs C (2158.33±197.33 pg/mL vs 1744.80±157.74 pg/mL; p < 0.064). By analysing the interobserver concordance we detected 70 % agreement as to sRAGE values detected in neonatal late-onset infections and sepsis, while procalcitonin was used as golden standard. CONCLUSION: Plasma sRAGE values reflect the severity of the inflammatory status in late-onset infection and sepsis in preterm neonates. Our results indicate that sRAGE could be a good potential biomarker of late-onset neonatal infection and sepsis (Tab. 2, Ref. 14).

The Role of Heat Shock Proteins in Leukemia.

Heat shock proteins (HSPs) HSP27, HSP70 and HSP90 are molecular chaperones; their expression is increased after exposure of cells to conditions of environmental stress, including heat shock, heavy metals, oxidative stress, or pathologic conditions, such as ischemia, infection, and inflammation. Their protective function is to help the cell cope with lethal conditions. The HSPs are a class of proteins which, in normal cells, are responsible for maintaining homeostasis, interacting with diverse protein substrates to assist in their folding, and preventing the appearance of folding intermediates that lead to misfolded or damaged molecules. They have been shown to interact with different key apoptotic proteins and play a crucial role in regulating apoptosis. Several HSPs have been demonstrated to directly interact with various components of tightly regulated caspase-dependent programmed cell death. These proteins also affect caspase-independent apoptosis by interacting with apoptogenic factors. Heat shock proteins are aberrantly expressed in hematological malignancies. Because of their prognostic implications and functional role in leukemias, HSPs represent an interesting target for antileukemic therapy. This review will describe different molecules interacting with anti-apoptotic proteins HSP70 and HSP90, which can be used in cancer therapy based on their inhibition.

Quantitative profiling of genes associated with cancer pathways in brain tumors.

BACKGROUND: Brain tumors are a heterogeneous group of malignancies characterized by inter- and intratumoral heterogeneity. Among them, the most aggressive and, despite advances in medicine, still incurable remains glioblastoma. One of the reasons is the high recurrence rate of the disease and resistance to temozolomide, a golden standard in chemotherapy of brain tumors. Therefore, mapping the pathways responsible for tumorigenesis at the transcriptional level may help to determine the causes and aggressive behavior among different glial tumors. PATIENTS AND METHODS: Biopsies from patients with astrocytoma (N = 6), glioblastoma (N = 22), and meningioma (N = 14) were included in the sample set. A control group consisted of RNA isolated from healthy human brain (N = 3). The reverse-transcribed cDNAs were analyzed using the Human Cancer PathwayFinder™ real-time PCR Array in a 96-well format. The expression of 84 genes belonging to 9 signaling pathways (angiogenesis, apoptosis, cell cycle and senescence, DNA damage and repair, epithelial-to-mesenchymal transition, hypoxia, overall metabolism, and telomere dynamics) was determined for each sample. RESULTS: By determining the relative expression of selected genes, we characterized the transcriptomic profile of individual brain malignancies in the context of signaling pathways involved in tumorigenesis. We observed deregulation in 50, 52.4 and 53.6% % of the genes in glioblastomas, meningiomas and astrocytomas, respectively. The most pronounced changes with statistical significance compared to control were observed in the genes associated with epithelial-to-mesenchymal transition (CDH2, FOXC2, GSC, SNAI2, and SOX10), cellular senescence (BMI1, ETS2, MAP2K1, and SOD1), DNA repair (DDB2, ERCC3, GADD45G, and LIG4), and dynamic of telomeres (TEP1, TERF2IP, TNKS, and TNKS2). CONCLUSION: Based on the obtained data, we can conclude that individual diagnoses differ in transcriptomic profile. An individual molecular approach is therefore necessary in order to provide comprehensive and targeted therapy on multiple metabolic pathways in the diagnosis of brain tumors.

[Five year-results of chemoresistance testing in cancer patients]. / Nase pät'rocné výsledky in vitro testovania chemorezistencie u onkologických pacientov.

BACKGROUNDS: Translational medicine is a medical field encompassing basic research and development of new diagnostic and therapeutic strategies for clinical practice. The present scientific paper focuses on our previous experience in the field of chemoresistance testing in patients with oncological diseases. MATERIAL AND METHODS: Since 2005, we sampled 71 patients with a leukaemia (AML, ALL and CML) and 92 patients with a solid tumour (lung and gastrointestinal tract cancer). Malignant cell in vitro drug resistance testing was carried out using cytotoxic methyl-thiazol tetrazolium (MTT) assay. RESULTS: Based on the LC50 (lethal concentration of a drug killing 50% of cell population), we found that patients with acute myeloblastic leukaemia exhibit a greater degree of resistance than patients with acute lymphoblastic leukaemia. In patients with bronchogenic carcinomas, primary resistance to cisplatin was identified in 28% of tested samples, paclitaxel 36%, vincristine 50%, etoposide 56%, vinorelbine 57%, topotecan 62%, gemcitabine 77% and dacarbazine 86%. CONCLUSION: In vitro tests with gastrointestinal tract cancers also suggested high effectiveness of cisplatin (with the exception of gastric carcinoma) that was comparable with 5-fluorouracil. Even though the MTT assay has some limitations (insufficient number of vital cells, possible contamination by non-malignant cells, etc.), this in vitro method proved very effective in testing malignant cell resistance to clinically used cytostatics.

[Semiquantitative analysis of mRNA aromatase expression in eutopic endometrium as a diagnostic marker of endometriosis and estrogen dependent diseases]. / Semikvantitatívna analýza expresie mRNA aromatázy v eutopickom endometriu ako diagnostický marker endometriózy a estrogéndependentných ochorení.

OBJECTIVE: To determine clinical benefits of mRNA aromatase expression in entopic endometrium as a diagnostic marker of endometriosis. DESIGN: Prospective clinical trial. SETTING: Department of Obstetrics and Gynaecology of Jessenius Medical Faculty and Faculty Hospital, Martin. METHODS: The expression of mRNA aromatase of eutopic endometrium was determined among women who underwent laparoscopy or laparotomy due to pelvic pain, infertility or benign pelvic tumor. Endometriosis was confirmed histologicaly and classified by rAFS. RESULTS: On the basis of entering criteria 23 women were enrolled in this study and divided into two subgroups: 12 endometriotic and 11 without endometriosis. Sensitivity of aromatase expression was 75% and specificity 54.5% at the cut-off value of at least minimal aromatase activity. By the presence of estrogen-dependent diseases- endometriosis, myomas or endometrial hyperplasia 18 women were compared to 5 disease free women. In this case, sensitivity of aromatase expression was 72.2 and specificity 80%. CONCLUSION: Aromatase expression in eutopic endometrium is a good diagnostic marker for endometriosis.

The metabolism of 5-methylcytosine residues in DNA.

The fundamental biochemical processes of 5-methylcytosine (5-mC) synthesis, maintenance, conversion and removal determine the time and spatial pattern of DNA methylation. This has a strong effect on a plethora of physiological aspects of cellular metabolism. While the presence of 5-mC within the promoter region can silence gene expression, its derivative - 5-hydroxymethylcytosine exerts an opposite effect. Dysregulations in the metabolism of 5-mC lead to an altered DNA methylation pattern which is linked with a disrupted epigenome, and are considered to play a significant part in the etiology of several human diseases. A summary of recent knowledge about the molecular processes participating in DNA methylation pattern shaping is provided here.

Effect of homocysteine on survival of human glial cells.

Several neurodegenerative conditions, such as Alzheimer's disease and Parkinson's disease, or vascular dementia and cognitive impairment, are associated with mild hyperhomocysteinemia. Hyperhomocysteinemia is defined as an increase of the homocysteine (Hcy) level beyond 10 microM. Although the adverse effect of Hcy on neurons is well documented, knowledge about the impact of this amino acid on glial cells is missing. Therefore, with the aim to evaluate the neurotoxic properties of Hcy on glial cells, we used a glioblastoma cell line as a study model. The viability of cells was assayed biochemically and cytologically. At a concentration around 50 microM in the culture medium D,L-Hcy induced cell death. It is noteworthy that Hcy induces cell death of human glial cells at concentrations encountered during mild hyperhomocysteinemia. Therefore, we propose that Hcy-induced impairment of neuronal functions along with damage of glial cells may contribute to the etiopathogenesis of neurodegenerative diseases associated with hyperhomocysteinemia.

Age-related oxidative modifications of proteins and lipids in rat brain.

Oxidants have been shown to play a major role in ageing and ageing-related neurodegenerative diseases. In the present study, we investigated the effect of ageing on oxidative damage to lipids and proteins in brain homogenate, mitochondria and synaptosomes of adult (6-month-old), old (15-month-old), and senescent (26-month-old) Wistar rats. There was a significant increase in thiobarbituric acid-reactive substances and conjugated dienes in homogenates, which indicate increased lipid peroxidation (LPO). Oxidative modifications of homogenate proteins were demonstrated by a loss of sulfhydryl content, accumulation of dityrosines and formation of protein conjugates with LPO-end products. Increase in protein conjugates with LPO-end products and a decrease in SH groups were observed also in mitochondria and synaptosomes, but dityrosine content was elevated only in synaptosomes. Protein surface hydrophobicity, measured by fluorescent probe 1-anilino-8-naphthalenesulfonate (ANS), was increased only in homogenate. These results suggest that besides mitochondria and synaptosomes other cellular compartments are oxidatively modified during brain ageing.