Effect of Global Brain Ischemia on Amyloid Precursor Protein Metabolism and Expression of Amyloid-Degrading Enzymes in Rat Cortex: Role in Pathogenesis of Alzheimer's Disease.

The incidence of Alzheimer's disease (AD) increases significantly following chronic stress and brain ischemia which, over the years, cause accumulation of toxic amyloid species and brain damage. The effects of global 15-min ischemia and 120-min reperfusion on the levels of expression of the amyloid precursor protein (APP) and its processing were investigated in the brain cortex (Cx) of male Wistar rats. Additionally, the levels of expression of the amyloid-degrading enzymes neprilysin (NEP), endothelin-converting enzyme-1 (ECE-1), and insulin-degrading enzyme (IDE), as well as of some markers of oxidative damage were assessed. It was shown that the APP mRNA and protein levels in the rat Cx were significantly increased after the ischemic insult. Protein levels of the soluble APP fragments, especially of sAPPß produced by ß-secretase, (BACE-1) and the levels of BACE-1 mRNA and protein expression itself were also increased after ischemia. The protein levels of APP and BACE-1 in the Cx returned to the control values after 120-min reperfusion. The levels of NEP and ECE-1 mRNA also decreased after ischemia, which correlated with the decreased protein levels of these enzymes. However, we have not observed any changes in the protein levels of insulin-degrading enzyme. Contents of the markers of oxidative damage (di-tyrosine and lysine conjugates with lipid peroxidation products) were also increased after ischemia. The obtained data suggest that ischemia shifts APP processing towards the amyloidogenic ß-secretase pathway and accumulation of the neurotoxic Aß peptide as well as triggers oxidative stress in the cells. These results are discussed in the context of the role of stress and ischemia in initiation and progression of AD.

The Role of Interleukin-6 Polymorphism (rs1800795) in Prostate Cancer Development and Progression.

BACKGROUND/AIM: Interleukin-6 is an important modulator of inflammation, which is one of the factors involved in prostate cancer. The aim of the study was to evaluate the possible association of the IL-6 -174 polymorphism (rs1800795) with the risk of prostate cancer development and progression. MATERIALS AND METHODS: The study population consisted of 446 prostate cancer patients, 377 benign prostatic hyperplasia (BHP) patients and 276 healthy men. Genotyping was performed by PCR-RFLP analysis. IL-6 plasma levels were measured by the ELISA method. RESULTS: The GC genotype (OR=0.61, p=0.005) and C allele (OR=0.8, p=0.04) of the IL-6 -174 polymorphism were significantly associated with prostate cancer. No genotype was associated with BHP. IL-6 plasma levels were significantly increased in prostate cancer patients compared to both healthy men (p=0.02) and BHP patients (p=0.008). No significant differences were observed in IL-6 plasma levels in connection with IL-6 -174 genotypes. CONCLUSION: The IL-6 -174 polymorphism was significantly associated with prostate cancer in Slovak patients.

Oxidative Stress and Bronchial Asthma in Children-Causes or Consequences?

Bronchial asthma is one of the most common chronic inflammatory diseases of the airways. In the pathogenesis of this disease, the interplay among the genes, intrinsic, and extrinsic factors are crucial. Various combinations of the involved factors determine and modify the final clinical phenotype/endotype of asthma. Oxidative stress results from an imbalance between the production of reactive oxygen species and reactive nitrogen species and the capacity of antioxidant defense mechanisms. It was shown that oxidative damage of biomolecules is strongly involved in the asthmatic inflammation. It is evident that asthma is accompanied by oxidative stress in the airways and in the systemic circulation. The oxidative stress is more pronounced during the acute exacerbation or allergen challenge. On the other hand, the genetic variations in the genes for anti-oxidative and pro-oxidative enzymes are variably associated with various asthmatic subtypes. Whether oxidative stress is the consequence of, or the cause for, chronic changes in asthmatic airways is still being discussed. Contribution of oxidative stress to asthma pathology remains at least partially controversial, since antioxidant interventions have proven rather unsuccessful. According to current knowledge, the relationship between oxidative stress and asthmatic inflammation is bidirectional, and genetic predisposition could modify the balance between these two positions-oxidative stress as a cause for or consequence of asthmatic inflammation.

Asociación entre polimorfismos genéticos de la interleucina 6 y el asma bronquial en niños / Association of Gene Polymorphisms in Interleukin 6 in Infantile Bronchial Asthma

Introducción: La base genética del asma bronquial es compleja y es probable que en su desarrollo contribuyan diversos genes a través de sus efectos principales e interacciones génicas. Las citocinas participan en diferentes aspectos del asma, determinando el tipo, la gravedad y los resultados patogénicos. Durante las crisis, los asmáticos alérgicos muestran concentraciones significativamente más altas de citocinas proinflamatorias, tales como interleucinas y quimiocinas. En los últimos años, se ha observado que las citocinas y sus receptores son muy polimórficos, por lo que investigamos los polimorfismos del gen promotor de la interleucina 6 en las posiciones -174G/C (rs1800795) y -572G/C (rs1800796) en el asma infantil. Métodos: Analizamos los polimorfismos del gen promotor de la interleucina 6 en pacientes con asma bronquial y niños sanos mediante el análisis de polimorfismos en la longitud de los fragmentos de restricción amplificados por reacción en cadena de la polimerasa. Resultados: Se observó una asociación significativa entre el polimorfismo en -174G/C y el asma bronquial (OR=3,4; IC 95%: 2,045-5,638; p<0,001). En pacientes atópicos se observó mayor asociación del polimorfismo del IL-6 -174G/C (OR=4,1; IC 95%: 2,308-7,280; p<8,10-7). Conclusiones: El polimorfismo de la interleucina 6 se asocia con el asma bronquial, especialmente con el fenotipo atópico. En pacientes asmáticos, la expresión y la secreción de interleucinas pueden resultar afectadas por polimorfismos génicos, lo que podría tener efectos modificadores de la enfermedad en la vía aérea y modificar la respuesta terapéutica (AU)

Introduction: The genetic background of bronchial asthma is complex, and it is likely that multiple genes contribute to its development both directly and through gene-gene interactions. Cytokines contribute to different aspects of asthma, as they determine the type, severity and outcomes of asthma pathogenesis. Allergic asthmatics undergoing an asthmatic attack exhibit significantly higher levels of pro-inflammatory cytokines, such as interleukins and chemokines. In recent years, cytokines and their receptors have been shown to be highly polymorphic, and this prompted us to investigate interleukin 6 promoter polymorphisms at position -174G/C (rs1800795) and at -572G/C (rs1800796) in relation to asthma in children. Methods: Interleukin 6 promoter polymorphisms were analyzed in bronchial asthma patients and healthy children using polymerase chain reaction-restriction fragment length polymorphism analysis. Results: We observed a significant association between polymorphism at -174G/C and bronchial asthma (OR=3.4, 95% CI: 2.045-5.638, P<.001). Higher associations between polymorphism at IL-6 -174G/C and bronchial asthma were observed in atopic patients (OR=4.1, 95% CI: 2.308-7.280, P<8.10-7). Conclusions: Interleukin 6 polymorphism is associated with bronchial asthma, particularly its atopic phenotype. Expression and secretion of interleukins in asthmatic patients may be affected by genetic polymorphisms, and could have a disease-modifying effect in the asthmatic airway and modify the therapeutic response (AU)

Association of Gene Polymorphisms in Interleukin 6 in Infantile Bronchial Asthma. / Asociación entre polimorfismos genéticos de la interleucina 6 y el asma bronquial en niños.

INTRODUCTION: The genetic background of bronchial asthma is complex, and it is likely that multiple genes contribute to its development both directly and through gene-gene interactions. Cytokines contribute to different aspects of asthma, as they determine the type, severity and outcomes of asthma pathogenesis. Allergic asthmatics undergoing an asthmatic attack exhibit significantly higher levels of pro-inflammatory cytokines, such as interleukins and chemokines. In recent years, cytokines and their receptors have been shown to be highly polymorphic, and this prompted us to investigate interleukin 6 promoter polymorphisms at position -174G/C (rs1800795) and at -572G/C (rs1800796) in relation to asthma in children. METHODS: Interleukin 6 promoter polymorphisms were analyzed in bronchial asthma patients and healthy children using polymerase chain reaction-restriction fragment length polymorphism analysis. RESULTS: We observed a significant association between polymorphism at -174G/C and bronchial asthma (OR=3.4, 95% CI: 2.045-5.638, P<.001). Higher associations between polymorphism at IL-6 -174G/C and bronchial asthma were observed in atopic patients (OR=4.1, 95% CI: 2.308-7.280, P<8.10-7). CONCLUSIONS: Interleukin 6 polymorphism is associated with bronchial asthma, particularly its atopic phenotype. Expression and secretion of interleukins in asthmatic patients may be affected by genetic polymorphisms, and could have a disease-modifying effect in the asthmatic airway and modify the therapeutic response.

Bone Metabolism of the Patient with a Malignant Melanoma during the Entry Examination and the Check-up of Whole-body Bone Scintigraphy.

Malignant melanoma is a malignancy located predominantly in the skin and the incidence of melanoma increases. We compared the markers of bone metabolism - osteocalcin (OC), beta-carboxyterminal cross-linked telopeptide of type I collagen (ß-CrossLaps, ß-CTx) and tumour marker - human epididymis protein 4 (HE4) in the serum with finding during the entry examination and the check-up of whole-body bone scintigraphy of the patient with a malignant melanoma. Serum concentrations of OC, ß-CTx, HE4 were determined in 1 patient (female, age 64 years) with malignant melanoma and correlated with the presence of equivocal bone metastases detected by whole-body bone scintigraphy (the entry examination and check-up after 6 months). Concentrations of bone metabolism markers decreased during six months and we observed progress in bone metastases. The change of the markers levels during the entry examination and the check-up of the whole-body bone scintigraphy with equivocal finding of bone metastases could be a sign of a possible initiating progression of malignant melanoma despite a clinically negative finding that does not prove the progression of the disease.

DNA Methylation Machinery in the Endometrium and Endometrial Cancer.

During the normal menstrual cycle, endometrial tissue undergoes many biochemical and morphological changes which are under the control of steroid hormone levels. DNA methylation plays a key role in gene expression regulation and influences functional changes in endometrial tissue. Eliminating senescent cells from the functional layer of the endometrium is mediated by apoptotic cell death, which helps maintain cellular homeostasis. Aberrant DNA methylation changes result in deregulation of important apoptotic proteins during endometrial carcinogenesis and thus apoptosis resistance development. Evading apoptosis is still a major problem in the successful treatment of endometrial cancer patients with advanced disease. Despite intensive study of the cancer epigenome, there is missing information about disrupted apoptotic gene regulation in DNA methylation levels. Therefore, it is necessary to spread our knowledge in the field of epigenetics to help us differentiate normal and cancer tissues and detect the early stages of cancer disease.

Estrogen receptor alpha polymorphisms and the risk of prostate cancer development.

PURPOSE: The main purpose of the study was to evaluate the effect of two polymorphisms in the estrogen receptor alpha, rs2077647 and rs3798577, on the development of prostate cancer, their correlation with selected clinical characteristics, as well as consideration of potential interactions between four estrogen receptor alpha polymorphisms (rs2077647, rs3798577, PvuII, XbaI). METHODS: The study was performed using 395 patients with histologically verified prostate cancer and 253 healthy male controls. RESULTS: The CC genotype of rs2077647 was significantly associated with prostate cancer (OR = 1.61). No association was found between rs3798577 polymorphism and prostate cancer. After stratification of patients according to the age at diagnosis and Gleason score, we observed significant correlation between rs2077647 polymorphism and prostate cancer risk in patients diagnosed before the age of 60 as well as patients with Gleason score <7, while rs3798577 was significantly associated with prostate cancer risk development in patients older than 60 and with Gleason score ≥7. Double analysis of each combination of four studied polymorphisms showed that presence of at least three variant alleles was associated with prostate cancer risk in all combinations, while each containing rs3798577 was significantly associated with development of high-grade carcinomas. CONCLUSIONS: The present study suggests that rs2077647 polymorphism may be a risk factor for prostate cancer especially in patients diagnosed before the age of 60, while rs3798577 polymorphism could probably serve rather as promoting factor in combination with other polymorphisms in estrogen receptor alpha contributing preferably to development of high-grade carcinomas.

Val66Met polymorphism in the BDNF gene in children with bronchial asthma.

OBJECTIVES: Bronchial asthma is a chronic respiratory disease characterized by airway inflammation. There is increasing evidence that neurotrophins play an important role in the development and maintenance of neurogenic airway inflammation in chronic allergic diseases. WORKING HYPOTHESIS: Brain-derived neurotrophic factor (BDNF) is a member of the neurotrophin family and has several important functions in the airways. There are only a few reports on the association between genetic variations in the BDNF gene and various allergic diseases, and the results are generally conflicting. Therefore, we aimed to study the functional polymorphism Val66Met (also called rs6265 or G196A) in the BDNF gene in a group of asthmatic children and healthy controls. STUDY DESIGN, PATIENT-SELECTION, AND METHODOLOGY: We studied 248 asthmatic patients (aged 12.28 ± 0.24 years) and 249 healthy children (aged 13.14 ± 0.48 years). Analysis of the Val66Met polymorphism of the BDNF gene was performed by polymerase chain reaction (PCR) and PCR products were digested by PmlI. RESULTS: The prevalence of the Val66Met polymorphisms (Val/Val, Val/Met, and Met/Met) was 61.7%, 33.5%, and 4.8% in asthmatics, respectively, and 47.0%, 51.8%, and 1.2% in healthy subjects, respectively. We observed a significant association of the Met/Met variant genotype with asthmatics (OR = 4.17, 95% CI = 1.16-14.96, P = 0.018). The Val/Met genotype was protective against bronchial asthma (OR = 0.69, 95% CI = 0.48-0.99, P = 0.045), especially in girls (OR = 0.34, 95% CI = 0.20-0.59, P = 0.001). CONCLUSION: Specific BDNF gene polymorphism may contribute to bronchial asthma susceptibility. Our study suggested the positive association between selected functional BDNF polymorphism (rs6265) and asthma in children.

Pulmonary manifestations of primary immunodeficiency disorders in children.

Primary immunodeficiencies (PIDs) are inherited disorders in which one or several components of immune system are decreased, missing, or of non-appropriate function. These diseases affect the development, function, or morphology of the immune system. The group of PID comprises more than 200 different disorders and syndromes and the number of newly recognized and revealed deficiencies is still increasing. Their clinical presentation and complications depend on the type of defects and there is a great variability in the relationship between genotypes and phenotypes. A variation of clinical presentation across various age categories is also presented and children could widely differ from adult patients with PID. Respiratory symptoms and complications present a significant cause of morbidity and also mortality among patients suffering from different forms of PIDs and they are observed both in children and adults. They can affect primarily either upper airways (e.g., sinusitis and otitis media) or lower respiratory tract [e.g., pneumonia, bronchitis, bronchiectasis, and interstitial lung diseases (ILDs)]. The complications from lower respiratory tract are usually considered to be more important and also more specific for PIDs and they determinate patients' prognosis. The spectrum of the causal pathogens usually demonstrates typical pattern characteristic for each PID category. The respiratory signs of PIDs can be divided into infectious (upper and lower respiratory tract infections and complications) and non-infectious (ILDs, bronchial abnormalities - especially bronchiectasis, malignancies, and benign lymphoproliferation). Early diagnosis and appropriate therapy can prevent or at least slow down the development and course of respiratory complications of PIDs.

Factors influencing the levels of exhaled carbon monoxide in asthmatic children.

OBJECTIVE: Bronchial asthma is characterised by chronic airway inflammation commonly associated with increased oxidative stress. Exhaled carbon monoxide (eCO) levels could act as markers of both oxidative stress and allergic inflammation. We aimed to study eCO levels in asthmatics and detect the possible factors influencing them. METHODS: We studied 241 asthmatic children and 75 healthy children. The differences in eCO levels among various asthmatic phenotypes and the correlations between eCO and other measured parameters (spirometric indices, Asthma Control Test score, exhaled nitric oxide, total IgE, blood eosinophils and marker of oxidative damage of proteins) were analysed. RESULTS: Levels of eCO widely differed according to the selected characteristics of asthma. Asthmatics showed higher eCO concentrations than controls (1.44 ± 0.12 ppm vs. 0.91 ± 0.11 ppm, p < 0.001). Acute exacerbation of asthma was accompanied by a significant increase in eCO compared to the clinically controlled stage (2.17 ± 0.36 ppm vs. 1.33 ± 0.13 ppm, p < 0.001). Atopic, non-atopic asthma and asthma associated with allergic rhinitis (AR) showed elevated levels of eCO. The levels of eCO negatively correlated with the marker of protein oxidation in asthmatics, especially in atopic form and during acute exacerbation. CONCLUSIONS: In a population of asthmatic children, eCO levels could be considered as a marker of both allergic inflammation and oxidative stress in the airways. Concomitant AR and asthma control were the most important factors affecting the levels of eCO in asthmatic children. However, our results do not support the use of routine eCO in the clinical practice.

Frecuencia del polimorfismo -262 C /T en el gen de la catalasa y lesión oxidativa en niños eslovacos con asma bronquial / Frequency of Polymorphism -262 C/T in Catalase Gene and Oxidative Damage in Slovak Children With Bronchial Asthma

Introducción: El asma bronquial es una enfermedad compleja en la que los factores genéticos, los factores ambientales y la lesión oxidativa son responsables del inicio y la modulación de su progresión. Si fracasan los mecanismos antioxidantes, las especies reactivas del oxígeno afectan a las biomoléculas, lo que se sigue de la progresión de la enfermedad. La catalasa es uno de los antioxidantes enzimáticos endógenos más importantes. En el presente estudio examinamos la hipótesis de que un aumento de la lesión oxidativa y el polimorfismo en el gen CAT (región promotora -262 C/T) se asocian a asma bronquial infantil. Pacientes y métodos: En niños sanos (249) y niños asmáticos (248) se efectuó una genotipificación de los polimorfismos en el gen CAT usando la reacción en cadena de la polimerasa-polimorfismo de longitud de fragmentos de restricción. Mediante espectrofotometría, en los niños se analizaron los marcadores de lesión oxidativa: el contenido de grupos sulfhidrilo y de sustancias reactivas al ácido tiobarbitúrico. Resultados: El genotipo TT de la catalasa fue más frecuente entre pacientes asmáticos (22,6%) que en niños sanos (4,8%) (odds ratio = 5,63; intervalo de confianza del 95% = 2,93–10,81; p < 0,001). El contenido de grupos sulfhidrilo disminuyó significativamente y, al contrario, el contenido de sustancias reactivas a ácido tiobarbitúrico aumentó significativamente en el asma bronquial y el genotipo TT de catalasa comparado con los otros genotipos catalasa de este gen. Conclusiones: Los resultados del presente estudio sugieren que el polimorfismo del gen de la catalasa podría participar en la aparición de asma bronquial y en el aumento de la lesión oxidativa en niños asmáticos. La variación genética de los antioxidantes enzimáticos podría modular el riesgo de la enfermedad (AU)

Introduction: Bronchial asthma is a complex disease in which genetic factors, environmental factors and oxidative damage are responsible for the initiation and modulation of disease progression. If antioxidant mechanisms fail, reactive oxygen species damage the biomolecules followed by progression of the disease. Catalase is one of the most important endogenous enzymatic antioxidants. In the present study, we examined the hypothesis that increased oxidative damage and polymorphism in the CAT gene (-262 promoter region, C/T) are associated with childhood bronchial asthma. Patients and methods: Genotyping of the polymorphisms in the CAT gene in healthy (249) and asthmatic children (248) was performed using polymerase chain reaction - restriction fragment length polymorphism. Markers of oxidative damage: content of sulfhydryl groups and thiobarbituric acid-reactive substances were determined by spectrophotometry in children. Results: The TT genotype of catalase was more frequent among the asthmatic patients (22.6%) than in healthy children (4.8%) (odds ratio=5.63; 95% confidence interval=2.93–10.81, P<0.001). The amount of sulfhydryl groups decreased significantly and conversely, the content of thiobarbituric acid-reactive substances increased significantly in bronchial asthma and in catalase TT genotype compared to other catalase genotypes of this gene. Conclusions: These results suggest that catalase polymorphism might participate in development of bronchial asthma and in enhanced oxidative damage in asthmatic children. Genetic variation of enzymatic antioxidants may modulate disease risk (AU)

The association between gene polymorphisms of glutathione S-transferase T1/M1 and type 1 diabetes in Slovak children and adolescents.

BACKGROUND: Considering a dramatic increase in the incidence of type 1 diabetes (T1D) worldwide, current research focuses on complex etiology of T1D where immune system, environmental and genetic factors play a significant role. Glutathione S-transferase family of enzymes protects tissue from oxidative damage which is discussed in the context of T1D. The aim of the study was to investigate an association of glutathione S-transferase mu 1 (GST M1) and glutathione S-transferase theta 1 (GST T1) polymorphisms with type 1 diabetes. METHODS: 163 children, 116 with type 1 diabetes and 47 healthy controls, at the age 6-19 years were enrolled to the study. Basic anthropometric, biochemical parameters and GST T1 diabetes and M1 polymorphisms were established in each subject. RESULTS: Subjects with T1D had significantly lower concentration of uric acid compared to the healthy subjects (212.85 +/- 57.10 micromol/l vs. 269.57 +/- 72.53; p < 0.001). GST T1 null genotype was more frequent in patients with diabetes compared to the healthy controls (36.2% vs. 21.3%) and represented 2.1-fold increased risk of T1D of borderline statistical significance (OR = 2.1; 95% Cl = 0.949-4.648; p = 0.06). GST T1 null/M1 wild genotype combination was more frequent in patients with diabetes (25.9% vs. 10.6%) and represented 2.9-fold increased risk for T1D development (OR = 2.93; 95% CI = 1.061-8.095; p = 0.032). CONCLUSION: The study indicates that GST T1 null genotype and GST T1 null/M1 wild combination could be considered a risk factor for type 1 diabetes development in Slovak children and adolescents.

Frequency of polymorphism -262 c/t in catalase gene and oxidative damage in Slovak children with bronchial asthma.

INTRODUCTION: Bronchial asthma is a complex disease in which genetic factors, environmental factors and oxidative damage are responsible for the initiation and modulation of disease progression. If antioxidant mechanisms fail, reactive oxygen species damage the biomolecules followed by progression of the disease. Catalase is one of the most important endogenous enzymatic antioxidants. In the present study, we examined the hypothesis that increased oxidative damage and polymorphism in the CAT gene (-262 promoter region, C/T) are associated with childhood bronchial asthma. PATIENTS AND METHODS: Genotyping of the polymorphisms in the CAT gene in healthy (249) and asthmatic children (248) was performed using polymerase chain reaction-restriction fragment length polymorphism. Markers of oxidative damage: content of sulfhydryl groups and thiobarbituric acid-reactive substances were determined by spectrophotometry in children. RESULTS: The TT genotype of catalase was more frequent among the asthmatic patients (22.6%) than in healthy children (4.8%) (odds ratio=5.63; 95% confidence interval=2.93-10.81, P<.001). The amount of sulfhydryl groups decreased significantly and conversely, the content of thiobarbituric acid-reactive substances increased significantly in bronchial asthma and in catalase TT genotype compared to other catalase genotypes of this gene. CONCLUSIONS: These results suggest that catalase polymorphism might participate in development of bronchial asthma and in enhanced oxidative damage in asthmatic children. Genetic variation of enzymatic antioxidants may modulate disease risk.

The association between glutathione S-transferase T1 and M1 gene polymorphisms and cardiovascular autonomic neuropathy in Slovak adolescents with type 1 diabetes mellitus.

Glutathione S-transferase (GST), as antioxidant enzyme, protects tissue from oxidative damage typical for many pathologic conditions as type 1 diabetes (T1D) and its chronic complications. The aim of the study was to compare the prevalence of GST T1/M1 gene polymorphisms between diabetic adolescents with (CAN+) and without (CAN-) cardiovascular autonomic neuropathy. Forty-six subjects with T1D at the age 15-19 years were enrolled. CAN was diagnosed in 19 patients (41.3%) based on standard cardiovascular tests. GST M1 null genotype was more prevalent in CAN+subjects but this was not statistically significant (OR=1.889, 0.61-6.55, p>0.05). GST T1 wild genotype nearly 5-fold increased the risk of CAN (OR=4.952, 1.13-21.739, p<0.05). Regarding genotype combination, GST T1/M1 wild/null genotype was significantly more frequent in CAN+compared to the CAN- subjects (OR=3.96, 1.024-15.302, p<0.05). No significant difference was found in any biochemical parameters between CAN+and CAN- subgroups. Multivariable logistic regression showed that none of the biochemical parameters estimated was considered a risk factor for CAN, however GST T1 wild and GST T1/M1 wild/null represented a risk factor for CAN development (OR=2.227, 1.079-4.587, p<0.05 and OR=1.990, 1.026-3.859, p<0.05, respectively). GST T1 wild allele and GST T1/M1 wild/null genotype can be considered as risk factors for CAN in Slovak adolescents with T1D.

Analysis of genetic polymorphisms of brain-derived neurotrophic factor and methylenetetrahydrofolate reductase in depressed patients in a Slovak (Caucasian) population.

Major depressive disorder (MDD) is a complex neuropsychiatric disorder where both gene-gene and gene-environment interactions play an important role, but the clues are still not fully understood. One carbon metabolism in the CNS plays a critical role in the synthesis and release of neurotransmitters which are relevant to depressive disorder. We studied genetic polymorphisms of the brain derived neurotrophic factor (BDNF) and the methylenetetrahydrofolate reductase (MTHFR) in association with major depressive disorder. We genotyped the BDNF G196A, the MTHFR C677T, and A1298C polymorphisms in 134 patients diagnosed with major depression and 143 control subjects in Slovak (Caucasian) cohort of patients and probands. We found no significant association of either the BDNF G196A or MTHFR C677T polymorphisms with major depressive disorder neither in female nor male group of patients. However, the MTHFR A1298C genotype distribution was 36.6% (for AA genotype), 48.5% (AC) and 14.9% (CC) for the depressed patients, and 48.9% (AA), 42.7% (AC) and 8.4% (CC), respectively, for the control subjects. Patients with MDD had a higher prevalence of the CC genotype (OR = 2.38; 95% CI = 1.07-5.32; p = 0.032) and the AC + CC genotype (OR = 1.67; 95% CI = 1.03-2.69; p = 0.037) in comparison with the control subjects. This study shows that CC genotype of the MTHFR A1298C is associated with higher risk of MDD in Slovak population.

Oxidative stress induced in rat brain by a combination of 3-nitropropionic acid and global ischemia.

In our investigation, we describe the complex model of brain oxidative stress consisted of combination of experimental brain ischemia and energy metabolism violation induced by irreversible inhibitor of mitochondrial succi-nate dehydrogenase, 3-nitropropionate (3-NPA). 3-NPA causes selective degeneration of striatum neurons, which is extremely sensitive to energy deficit. This complex model allows revealing not only biochemical but also neurological symptoms in experimental animals that permits proper estimation of protective effect of different drugs on animal status. Combination of global ischemia induced by 3-vessel occlusion of major arteries supplys rat brain and subsequent 5-day reperfusion with intraperitoneal injection of 3-nitropropionic acid induces vigorous oxidative stress in brain tissues accompanied by evident neurological symptoms in Wistar rats. Such a combination of damaging factors may be considered as a new complex experimental model of brain oxidative stress permitting the evaluation of neuroprotective effect of potential therapeutic agents. Using this model, protective effect of neuropeptide carnosine was demonstrated which is in agreement with previous data.

Myocardial Ca2+ handling and cell-to-cell coupling, key factors in prevention of sudden cardiac death.

Using whole-heart preparations, we tested our hypothesis that Ca(2+) handling is closely related to cell-to-cell coupling at the gap junctions and that both are critical for the development and particularly the termination of ventricular fibrillation (VF) and hence the prevention of sudden arrhythmic death. Intracellular free calcium concentration ([Ca(2+)](i)), ECG, and left ventricular pressure were continuously monitored in isolated guinea pig hearts before and during development of low K(+)-induced sustained VF and during its conversion into sinus rhythm facilitated by stobadine. We also examined myocardial ultrastructure to detect cell-to-cell coupling alterations. We demonstrated that VF occurrence was preceded by a 55.9% +/- 6.2% increase in diastolic [Ca(2+)](i), which was associated with subcellular alterations indicating Ca(2+) overload of the cardiomyocytes and disorders in coupling among the cells. Moreover, VF itself further increased [Ca(2+)](i) by 58.2% +/- 3.4% and deteriorated subcellular and cell-to-cell coupling abnormalities that were heterogeneously distributed throughout the myocardium. In contrast, termination of VF and its conversion into sinus rhythm was marked by restoration of basal [Ca(2+)](i), resulting in recovery of intercellular coupling linked with synchronous contraction. Furthermore, we have shown that hearts exhibiting lower SERCA2a (sarcoplasmic reticulum Ca(2+)-ATPase) activity and abnormal intercellular coupling (as in older guinea pigs) are more prone to develop Ca(2+) overload associated with cell-to-cell uncoupling than hearts with higher SERCA2a activity (as in young guinea pigs). Consequently, young animals are better able to terminate VF spontaneously. These findings indicate the crucial role of Ca(2+) handling in relation to cell-to-cell coupling in both the occurrence and termination of malignant arrhythmia.

In vitro assays for the evaluation of drug resistance in tumor cells.

Oncologic diseases are among leading cause of mortality in developed countries. Despite significant progress, the use of standard cytotoxic chemotherapy has reached a therapeutical plateau. Currently, the process of selecting chemotherapy represents a trial and error method neglecting biological individuality of tumor and its bearer. The improvement of treatment results is expected from ex vivo drug sensitivity testing which may allow to choose the most effective drug for individual patient and to exclude agents to which the tumor cells exert resistance. New techniques and rapidly increasing knowledge about the molecular basis of malignant diseases provide important opportunities for the future of chemotherapy. This paper reviews current methods used to test the resistance of tumor cells to a panel of anticancer agents in vitro. In addition, we focused on the in vitro MTT assay which represents one of major technique for testing of tumor cell resistance to anticancer agents.

Carnosine protects the brain of rats and Mongolian gerbils against ischemic injury: after-stroke-effect.

Carnosine, a specific constituent of excitable tissues of vertebrates, exhibits a significant antioxidant protecting effect on the brain damaged by ischemic-reperfusion injury when it was administered to the animals before ischemic episode. In this study, the therapeutic effect of carnosine was estimated on animals when this drug was administered intraperitoneally (100 mg/kg body weight) after ischemic episode induced by experimental global brain ischemia. Treatment of the animals with carnosine after ischemic episode under long-term (7-14 days) reperfusion demonstrated its pronounced protective effect on neurological symptoms and animal mortality. Carnosine also prevented higher lipid peroxidation of brain membrane structures and increased a resistance of neuronal membranes to the in vitro induced oxidation. Measurements of malonyl dialdehyde (MDA) in brain homogenates showed its increase in the after brain stroke animals and decreased MDA level in the after brain stroke animals treated with carnosine. We concluded that carnosine compensates deficit in antioxidant defense system of brain damaged by ischemic injury. The data presented demonstrate that carnosine is effective in protecting the brain in the post-ischemic period.