Hyperhomocysteinemia-Induced Alterations in Protein Expression and Oxidative Stress Parameters in Rat Heart.

Hyperhomocysteinemia (HHcy) is considered an independent risk factor of cardiovascular diseases. Among the proposed mechanisms underlying homocysteine toxicity are altered protein expression and induction of oxidative stress. In the present study, we explored protein abundance and parameters related to oxidative stress in heart homogenates of rats exposed to chronic mild HHcy. Using two-dimensional gel electrophoresis followed by MALDI-TOF/TOF mass spectrometry 22 altered proteins (6 upregulated and 14 downregulated) were identified. For eight proteins the altered abundances were validated by Western blot analysis. Identified proteins are primarily involved in energy metabolism (mainly enzymes of glycolysis, pyruvate dehydrogenase complex, citric acid cycle, and ATP synthase), cardiac muscle contraction (alpha-actin and myosin light chains), stress response (heat-shock protein beta1 and alphaB-crystallin) and antioxidant defense (glutathione peroxidase 1). Diminished antioxidant defense was confirmed by decreases in total antioxidant capacity and GSH/GSSG ratio. Consistent with the decline in enzymatic and non-enzymatic antioxidant defense the protein oxidative modification, as determined by tyrosine nitration, was significantly increased. These findings suggest that both, altered protein expression and elevated oxidative stress contribute to cardiovascular injury caused by HHcy. Keywords: Homocysteine, Heart, Protein abundance, Antioxidant capacity, Nitrotyrosines.

The impact of ATP-sensitive potassium channel modulation on mitochondria in a Parkinson's disease model using SH-SY5Y cells depends on their differentiation state.

Inward rectifying potassium channels sensitive to ATP levels (KATP) have been the subject of investigation for several decades. Modulators of KATP channels are well-established treatments for metabolic as well as cardiovascular diseases. Experimental studies have also shown the potential of KATP modulation in neurodegenerative disorders. However, to date, data regarding the effects of KATP antagonists/agonists in experiments related to neurodegeneration remain inconsistent. The main source of confusion in evaluating available data seems to be the choice of experimental models. The present study aims to provide a comprehensive understanding of the effects of both opening and blocking KATP channels in two forms of SH-SY5Y cells. Our results offer valuable insights into the significance of metabolic differences between differentiated and non-differentiated SH-SY5Y cells, particularly in the context of glibenclamide and diazoxide effects under normal conditions and during the initiation of pathological events simulating Parkinson's disease in vitro. We emphasize the analysis of mitochondrial functions and changes in mitochondrial network morphology. The heightened protein expression of KATP channels identified in non-differentiated SH-SY5Y cells seems to be a platform for a more significant impact of KATP modulators in this cell type. The efficiency of rotenone treatment in inducing morphological changes in the mitochondrial network depends on the differentiation status of SH-SY5Y cells.

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.

NMR plasma metabolomics study of patients overcoming acute myocardial infarction: in the first 12 h after onset of chest pain with statistical discrimination towards metabolomic biomarkers.

Acute myocardial infarction (AMI) is one of the leading causes of death among adults in older age. Understanding mechanisms how organism responds to ischemia is essential for the ischemic patient's prevention and treatment. Despite the great prevalence and incidence only a small number of studies utilize a metabolomic approach to describe AMI condition. Recent studies have shown the impact of metabolites on epigenetic changes, in these studies plasma metabolites were related to neurological outcome of the patients making metabolomic studies increasingly interesting. The aim of this study was to describe metabolomic response of an organism to ischemic stress through the changes in energetic metabolites and aminoacids in blood plasma in patients overcoming acute myocardial infarction. Blood plasma from patients in the first 12 h after onset of chest pain was collected and compared with volunteers without any history of ischemic diseases via NMR spectroscopy. Lowered plasma levels of pyruvate, alanine, glutamine and neurotransmitter precursors tyrosine and tryptophan were found. Further, we observed increased plasma levels of 3-hydroxybutyrate and acetoacetate in balance with decreased level of lipoproteins fraction, suggesting the ongoing ketonic state of an organism. Discriminatory analysis showed very promising performance where compounds: lipoproteins, alanine, pyruvate, glutamine, tryptophan and 3-hydroxybutyrate were of the highest discriminatory power with feasibility of successful statistical discrimination.

Age-Associated Changes in Antioxidants and Redox Proteins of Rat Heart.

Oxidative stress and decline in cellular redox regulation have been hypothesized to play a key role in cardiovascular aging; however, data on antioxidant and redox regulating systems in the aging heart are controversial. The aim of the present study was to examine the effect of aging on critical antioxidant enzymes and two major redox-regulatory systems glutathione (GSH) and thioredoxin (Trx) system in hearts from adult (6-month-old), old (15-month-old), and senescent (26-month-old) rats. Aging was associated with a non-uniform array of changes, including decline in contents of reduced GSH and total mercaptans in the senescent heart. The activities of Mn-superoxide dismutase (SOD2), glutathione peroxidase (GPx), glutathione reductase (GR), and thioredoxin reductase (TrxR) exhibited an age-related decline, whereas catalase was unchanged and Cu,Zn-superoxide dismutase (SOD1) displayed only slight decrease in old heart and was unchanged in the senescent heart. GR, Trx, and peroxiredoxin levels were significantly reduced in old and/or senescent hearts, indicating a diminished expression of these proteins. In contrast, SOD2 level was unchanged in the old heart and was slightly elevated in the senescent heart. Decline in GPx activity was accompanied by a loss of GPx level only in old rats, the level in senescent heart was unchanged. These results indicate age-related posttranslational protein modification of SOD2 and GPx. In summary, our data suggest that changes are more pronounced in senescent than in old rat hearts and support the view that aging is associated with disturbed redox balance that could alter cellular signaling and regulation.

Benefits of anticitrullinated peptides examination in rheumatoid arthritis.

BACKGROUND: Anti-citrullinated peptides antibodies (ACPA) are specific for rheumatoid arthritis and have been implicated in disease pathogenesis. ACPA examination is a new component of ACR/EULAR 2010 classification criteria for rheumatoid arthritis. ACPA positivity predicts a more erosive disease course with severe joint damage and extra-articular manifestations. OBJECTIVES: To evaluate the benefits of ACPA examination in patients with early undifferentiated arthritis and patients with rheumatoid arthritis. METHODS: We examined patients with arthritis and tested them for ACPA positivity. In every individual patient we evaluated if ACPA examination was necessary to establish the diagnosis of rheumatoid arthritis, or to change treatment, or if the diagnosis could have been established without ACPA examination (ACR/EULAR 2010 classification criteria was met without ACPA scoring). RESULTS AND CONCLUSIONS: The study was placed in Slovak Republic. We examined 833 patients with arthritis. There were 43 patients, or 62% of a subgroup of 69 who were ACPA positive whose ACPA examination was not needed-ACR/EULAR criteria was met without ACPA scoring. This number represents 5.1% of the total number examined. There were 15 patients, or 22% of the subgroup and 1.8% of the total whose diagnosis was revised to rheumatoid arthritis due to ACPA positivity-ACR/EULAR criteria were met solely with ACPA scoring. There were 11 patients (16% and 1.3%) whose medication was changed due to ACPA positivity. ACPA examination is useful in 3.1% of all examined patients. When we correlate data on ACPA positive patients, 38% of the patients profit from ACPA examinations. Considering the relatively low price of ACPA testing, this examination should not be excluded.

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.

Age-associated changes in Ca(2+)-ATPase and oxidative damage in sarcoplasmic reticulum of rat heart.

Altered Ca(2+) handling may be responsible for the development of cardiac contractile dysfunctions with advanced age. In the present study, we investigated the roles of oxidative damage to sarcoplasmic reticulum (SR) and expression of Ca(2+)-ATPase (SERCA 2a) and phospholamban in age-associated dysfunction of cardiac SR. SR vesicles were prepared from hearts of 2-, 6-, 15-, and 26-month-old Wistar rats. Although activity of Ca(2+)-ATPase decreased with advancing age, no differences in relative amounts of SERCA 2a and phospholamban protein were observed. On the other hand, significant accumulation of protein oxidative damage occurred with aging. The results of this study suggest that age-related alteration in Ca(2+)-ATPase activity in the rat heart is not a consequence of decreased protein levels of SERCA 2a and phospholamban, but could arise from oxidative modifications of SR proteins. Cellular oxidative damage caused by reactive oxygen species could contribute to age-related alternations in myocardial relaxation.

Why mitochondria are excellent targets for cancer therapy.

New insights into cancer cells - specific biological pathways are urgently needed to promote development of exactly targeted therapeutics. The role of oncoproteins and tumor suppressor proteins in proliferative signaling, cell cycle regulation and altered adhesion is well established. Chemicals, viruses and radiation are also generally accepted as agents that commonly induce mutations in genes encoding these cancer-inducing proteins, thereby giving rise to cancer. More recent evidence indicates the importance of two additional key factors imposed on proliferating cells - hypoxia and/or lack of glucose. These two additional triggers can initiate and promote the process of malignant transformation, when a low percentage of cells escape cellular senescence. Disregulated cell proliferation leads to formation of cellular masses that extend beyond the resting vasculature, resulting in oxygen and nutrient deprivation. Resulting hypoxia triggers a number of critical adaptations that enable cancer cell survival. The process of apoptosis is suppressed and glucose metabolism is altered. Recent investigations suggest that oxygen depletion stimulates mitochondria to compensate increased reactive oxygen species (ROS). It activates signaling pathways, such as hypoxia-inducible factor 1, that promote cancer cell survival and tumor growth. During the last decade, mitochondria have become key organelles involved in chemotherapy-induced apoptosis. Therefore, the relationship between mitochondria, ROS signaling and activation of survival pathways under hypoxic conditions has been the subject of increased study. Insights into mechanisms involved in ROS signaling may offer novel ways to facilitate discovery of cancer-specific therapies.

[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.

Effects of aging on activities of mitochondrial electron transport chain complexes and oxidative damage in rat heart.

Mitochondrial dysfunction and accumulation of oxidative damage have been implicated to be the major factors of aging. However, data on age-related changes in activities of mitochondrial electron transport chain (ETC) complexes remain controversial and molecular mechanisms responsible for ETC dysfunction are still largely unknown. In this study, we examined the effect of aging on activities of ETC complexes and oxidative damage to proteins and lipids in cardiac mitochondria from adult (6-month-old), old (15-month-old) and senescent (26-month-old) rats. ETC complexes I-IV displayed different extent of inhibition with age. The most significant decline occurred in complex IV activity, whereas complex II activity was unchanged in old rats and was only slightly reduced in senescent rats. Compared to adult, old and senescent rat hearts had significantly higher levels of malondialdehyde, 4-hydroxynonenal (HNE) and dityrosine, while thiol group content was reduced. Despite marked increase in HNE content with age (25 and 76 % for 15- and 26-month-old rats, respectively) Western blot analysis revealed only few HNE-protein adducts. The present study suggests that non-uniform decline in activities of ETC complexes is due, at least in part, to mitochondrial oxidative damage; however, lipid peroxidation products appear to have a limited impact on enzyme functions.

Ischemia-reperfusion induces inhibition of mitochondrial protein synthesis and cytochrome c oxidase activity in rat hippocampus.

Dysfunction of mitochondria induced by ischemia is considered to be a key event triggering neuronal cell death after brain ischemia. Here we report the effect of ischemia-reperfusion on mitochondrial protein synthesis and activity of cytochrome c oxidase (EC 1.9.3.1, COX). By performing 4-vessel occlusion model of global brain ischemia, we have observed that 15 min of global ischemia led to the inhibition of COX subunit I (COXI) synthesis to 56 % of control. After 1, 3 and 24 h of reperfusion, COXI synthesis was inhibited to 46, 50 and 72 % of control, respectively. Depressed synthesis of COXI was not a result of either diminished transcription of COXI gene or increased proteolytic degradation of COXI, since both Northern hybridization and Western blotting did not show significant changes in COXI mRNA and protein level. Thus, ischemia-reperfusion affects directly mitochondrial translation machinery. In addition, ischemia in duration of 15 min and consequent 1, 3 and 24 h of reperfusion led to the inhibition of COX activity to 90.3, 80.3, 81.9 and 83.5 % of control, respectively. Based on our data, we suggest that inhibition of COX activity is rather caused by ischemia-induced modification of COX polypeptides than by inhibition of mitochondrial translation.

[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.

Oxidative alternations in rat heart homogenate and mitochondria during ageing.

Our understanding of the role played by reactive oxygen and nitrogen species in disease pathology and ageing is still insufficient. Reactive oxygen species and reactive nitrogen species can initiate protein and lipid oxidative damage that may be the most important contribution to ageing and age-related heart diseases. In the present study, we investigated the effect of ageing on oxidative damage of protein amino acid residues and lipids in heart homogenate and mitochondria of 4- and 26-month-old Wistar rats. Levels of dityrosine and levels of lysine conjugates increased in heart homogenate during ageing, although levels of conjugated dienes did not change. We observed significantly oxidative modification of tryptophan in heart mitochondria and increased levels of dityrosine with advancing age. However, levels of lysine conjugates, conjugated dienes as well as relative level of cytochrome c oxidase were unchanged in heart mitochondria during ageing. The results of this study suggest a different mechanism of oxidative modification in heart compartments during ageing and moreover, mitochondria and other cellular compartments are targets for oxidative modifications.

Effect of aging on the expression of intracellular Ca(2+) transport proteins in a rat heart.

Aging process is accompanied by various biological dysfunctions including altered calcium homeostasis. Modified calcium handling might be responsible for changed cardiac function and potential development of the pathological state. In the present study we compared the mRNA and protein levels of the intracellular Ca(2+)-handling proteins--inositol 1,4,5-trisphosphate receptor (IP(3)R), ryanodine receptor (RyR), sarcoplasmic reticulum Ca(2+) pump (SERCA2), and also transient receptor potential C (TRPC) channels in cardiac tissues of 5-, 15-, and 26-month-old rats. Aging was accompanied by significant increase in the mRNA levels of IP(3)R and TRPC channels in both ventricles and atria, but mRNA level of the type 2 RyR was unchanged. Protein content of the IP(3)R1 correlated with mRNA levels, in the left ventricle of 15- and 26-month-old rats the value was approximately 1.8 and 2.8-times higher compared to 5-month-old rats. No significant differences were observed in mRNA and protein levels of the SERCA2 among 5-month-old and aged rats. However, Ca(2+)-ATPase activity significantly decreased with age, activities in 5-, 15-, and 26-month-old rats were 421.2 +/- 13.7, 335.5 +/- 18.1 and 304.6 +/- 14.8 nmol P(i) min(-1) mg(-1). These results suggest that altered transporting activity and/or gene expression of Ca(2+)-handling proteins of intracellular Ca(2+) stores might affect cardiac function during aging.

Association of p53 polymorphisms with breast cancer: a case-control study in Slovak population.

Protein p53 is the tumor suppressor involved in cell cycle control and apoptosis. As a transcription factor p53 controls many cell processes and helps in prevention of cancer development. The p53 gene is polymorphic. Polymorphisms can affect the important regions involved in protein tumor suppressor activity. The well-known polymorphisms are the polymorphisms BstUI in exon 4 and MspI in intron 6. Both are supposed to be associated with cancer development. The purpose of this study was to investigate the genotype frequencies and associations of these polymorphisms with breast cancer in Slovak population. We observed the prevalence of BstUIPro (27.47%) and MspIA1 (17.58%) alleles and BstUIPro/Pro (8.79%) and MspIA1/A1 (5.49%) genotypes in breast cancer patients in comparison with controls 23.40%, 14.10%, 5.77%, 1.92% respectively. However the differences were not significant. After division of the cases and controls according to the age the prevalence of the risk alleles and genotypes in women at the age 50 years or less was higher as compared to women older than 50 years. In the younger women group, the p53 BstUI polymorphism genotype frequencies were 6.2% for BstUIPro/Pro, 31.0% for BstUIArg/Pro and 62.8% for BstUIArg/Arg in controls and 11.11 %, 40.74% and 48.15% in cases respectively. The risk of disease for BstUIPro/Pro genotype was more than two-fold higher in comparison with the BstUIArg/Arg (OR=2.34, 95% CI=0.53-10.24). In p53 MspI the genotype frequencies were 1.77% for MspIA1/A1, 24.78% for MspIA1/A2 and 73.45% for MspIA2/A2 in controls and 11.11%, 18.52% and 70.37% in cases respectively. The risk of disease for MspIA1/A1 genotype was more than six-fold higher in comparison with the MspIA2/A2 (OR=6.55, 95% CI=1.02-41.98). When we evaluated the association of both polymorphisms together with the breast cancer risk we observed that the highest risk was connected with the genotype BstUIPro/Pro / MspIA1/A1 (OR=2.99, 95% CI=0.69-13.06). Our results indicate that both BstUI and MspI p53 polymormphisms might play the role in the breast cancer development especially in women younger than 50 years.

Deficiency in parvalbumin, but not in calbindin D-28k upregulates mitochondrial volume and decreases smooth endoplasmic reticulum surface selectively in a peripheral, subplasmalemmal region in the soma of Purkinje cells.

The Ca(2+)-binding proteins parvalbumin (PV) and calbindin D-28k (CB) are key players in the intracellular Ca(2+)-buffering in specific cells including neurons and have profound effects on spatiotemporal aspects of Ca(2+) transients. The previously observed increase in mitochondrial volume density in fast-twitch muscle of PV-/- mice is viewed as a specific compensation mechanism to maintain Ca(2+) homeostasis. Since cerebellar Purkinje cells (PC) are characterized by high expression levels of the Ca(2+) buffers PV and CB, the question was raised, whether homeostatic mechanisms are induced in PC lacking these buffers. Mitochondrial volume density, i.e. relative mitochondrial mass was increased by 40% in the soma of PV-/- PC. Upregulation of mitochondrial volume density was not homogenous throughout the soma, but was selectively restricted to a peripheral region of 1.5 microm width underneath the plasma membrane. Accompanied was a decreased surface of subplasmalemmal smooth endoplasmic reticulum (sPL-sER) in a shell of 0.5 microm thickness underneath the plasma membrane. These alterations were specific for the absence of the "slow-onset" buffer PV, since in CB-/- mice neither changes in peripheral mitochondria nor in sPL-sER were observed. This implicates that the morphological alterations are aimed to specifically substitute the function of the slow buffer PV. We propose a novel concept that homeostatic mechanisms of components involved in Ca(2+) homeostasis do not always occur at the level of similar or closely related molecules. Rather the cell attempts to restore spatiotemporal aspects of Ca(2+) signals prevailing in the undisturbed (wildtype) situation by subtly fine tuning existing components involved in the regulation of Ca(2+) fluxes.

Genetically modified animals and human medicine.

Development of the methods of molecular and cellular biology now allows specific genetic manipulations of laboratory animals leading to the introduction of an exogenous gene to their genome or elimination of a particular endogenous gene. This approach represents an invaluable biological tool for a better understanding of basic physiological and pathological processes. In all fields of biomedical research, transgenic and knockout animals have contributed greatly to understanding the molecular cause of several human diseases and allowed production of their animal models, which represent a useful tool for development of new medical drugs and therapeutic procedures for the treatment of human diseases. The aim of this short review is to provide a brief survey of the production of genetically modified animal and to discus their importance human medicine. Fig. 2, Ref. 19.)

Ion transport systems as targets of free radicals during ischemia reperfusion injury.

Oxidative stress is a recognized pathogenic factor in ischemia/reperfusion injury (IRI). Iron induced generation of reactive oxygen species (ROS) in vitro reduces both the Na+K+-ATPase activity and Na+-Ca2+ exchanger of synaptosomal membranes, concomitantly with alteration of physical state of membranes. Oxidative insult also leads to the loss of ability of endoplasmic reticular membranes (ER) to sequester Ca2+ as well as to the increase of Ca2+ permeability. Furthermore, ROS induces both lipid peroxidation and lipid-independent modifications of membrane proteins. Acute in vivo ischemia alters kinetic parameters of Na+K+-ATPase affecting mainly the dephosphorylation step of ATPase cycle with parallel changes of Na+-Ca2+ exchanger and alterations of physical membrane environment. Subsequent reperfusion after ischemia is associated with decrease of immuno signal for PMCA 1 isoform in hippocampus. In addition, incubation of non-ischemic membranes with cytosol from ischemic hippocampus decreases level of PMCA 1 in non-ischemic tissues. Loss of PMCA 1 protein is partially protected both by calpain- and by non-specific protease inhibitors which suggest possible activation of proteases in the reperfusion period. On the other hand, ischemia does not affect the level of Ca2+ pump (SERCA 2b) and calreticulin of intracellular Ca2+ stores. However, IRI resulted in a decrease of IP3 receptor I and altered active Ca2+ accumulation into the ER. A non-specific alteration of physical properties of total membranes such as the oxidative modifications of proteins as well as the content of lipoperoxidation products can also be detected after IRI. ROS can alter physical and functional properties of neuronal membranes. We discuss our results suggesting that ischemia-induced disturbation of ion transport systems may participate in or follow delayed death of neurons after ischemia.

Deficiency in parvalbumin increases fatigue resistance in fast-twitch muscle and upregulates mitochondria.

The soluble Ca2+-binding protein parvalbumin (PV) is expressed at high levels in fast-twitch muscles of mice. Deficiency of PV in knockout mice (PV -/-) slows down the speed of twitch relaxation, while maximum force generated during tetanic contraction is unaltered. We observed that PV-deficient fast-twitch muscles were significantly more resistant to fatigue than were the wild type. Thus components involved in Ca2+ homeostasis during the contraction-relaxation cycle were analyzed. No upregulation of another cytosolic Ca2+-binding protein was found. Mitochondria are thought to play a physiological role during muscle relaxation and were thus analyzed. The fractional volume of mitochondria in the fast-twitch muscle extensor digitorum longus (EDL) was almost doubled in PV -/- mice, and this was reflected in an increase of cytochrome c oxidase. A faster removal of intracellular Ca2+ concentration ([Ca2+]i) 200-700 ms after fast-twitch muscle stimulation observed in PV -/- muscles supports the role for mitochondria in late [Ca2+]i removal. The present results also show a significant increase of the density of capillaries in EDL muscles of PV -/- mice. Thus alterations in the dynamics of Ca2+ transients detected in fast-twitch muscles of PV -/- mice might be linked to the increase in mitochondria volume and capillary density, which contribute to the greater fatigue resistance of these muscles.