Thermodynamic and kinetic processes during the unfolding of BSA in the presence of the mycotoxin patulin

The effects of the mycotoxin patulin on the thermodynamics and kinetics of the transition of bovine serum albumin (BSA) in aqueous solution were studied by Differential Scanning Calorimetry and Photoluminescence methods. Results show that in the presence of patulin, the free enthalpy change during the transition of BSA was decreased by an average of ∼ 46 kJ/mol, the free energy change was decreased by ∼ 4 kJ/mol, and the activation energy fell from ∼ 1546 to ∼ 840 kJ/mol. These results indicate that the bioactivity of patulin is based on the kinetic rather than on the thermodynamic properties of the transition. This is the first evidence of the direct interaction of patulin with the free thiol-containing BSA, a process which could contribute to the adverse cyto- and genotoxic effects induced by patulin.

Regulation of patulin-induced oxidative stress processes in the fission yeast Schizosaccharomyces pombe

Patulin (PAT), is one of the most widely disseminated mycotoxins found in agricultural products. In this study the PAT-induced accumulation of reactive oxygen species (ROS) and the regulation of the specific activities of antioxidant enzymes were investigated in the single cell eukaryotic organism Schizosaccharomyces pombe. In comparison with the untreated cells, 500 μM PAT treatment caused a 43% decrease in the concentration of the main intracellular antioxidant, glutathione (GSH); this depletion of GSH initiated a 2.44- and a 2.6-fold accumulation of superoxide anion and hydrogen peroxide, respectively, but did not increase the concentration of hydroxyl radicals; the reduction of ROS-induced adaptation processes via the activation of Pap1 transcription factor resulted in significantly increased specific activities of Cu/Zn superoxide dismutase, catalase and glutathione S-transferase to protect the cells against the ROS-induced unbalanced redox state. However, no change was measured in the activities of glutathione reductase, glutathione peroxidase and glucose-6-phosphate dehydrogenase. It seems reasonable to assume that the temporary PAT-induced ROS accumulation plays a crucial role in adaptation processes. The adverse effects of PAT may be exerted mainly through the destruction of cellular membranes and protein/enzyme functions.

Stroke prevention--a population screening day in district XII of Budapest

Along with advances in the treatment of acute stroke, new efforts have been made to enhance efficiency of the prevention of cerebrovascular diseases. Population screening is a way to contact high-risk patients, and there is an increasing international and national experience with the procedure. However, efforts are associated with high costs, so an efficient method, complying with local features, should be selected from the various methods. A stroke prevention day was organized in Szent János Hospital, localized in district XII, and data were analyzed. Taking advantage of the potentials of a large hospital, a comprehensive risk assessment - within the capacity of health care workers - was performed. Program and contact information of the screening day was published in the local newspaper of the district. Data of 48 residents of the district were analyzed. In addition to neurologists, a radiologist, a cardiologist and an ophtalmologist, as well as health care workers were involved in the project. A data sheet was filled in for all participants, including known risk factors, BMI, blood pressure and serum cholesterol levels. All participants had duplex sonography of the cervical vessels, cardiac evaluation and ophtalmic examination. Data were analyzed anonymously, and - if participants approved - postcode and educational level were also recorded. Among the 48 individuals screened, 35 were female and 13 were male. Average age was 62.86 (+/- 8.57) years, and participants were typically of higher educational level. 5 individuals had no known risk factors, most of them had 2-3 risk factors, and multiple risk factors were not uncommon. Individuals with six and seven risk factors were also found. 20 of 27 patients with known hypertension had target blood pressure levels. By duplex sonography, 36 individuals had mild, 4 had significant atherosclerosis. There was no significant carotid stenosis or occlusion. Based on ophtalmic evaluation, 26 patients had signs of vascular disease (mainly hypertensive fundus changes). Cardiac evaluation detected 14 patients with cardiovascular risk. The high standard of primary care in the district was reflected by the fact that all the 6 high-risk individuals were already in the care of general practitioners (GP-s). One of the main conclusions from the evaluation of the data is that the press, family and local communities play a major role in recruiting people for a screening day. In order to increase efficiency and cost-effectiveness of the program, GP-s should also be involved in the planning process, because efficiency may be increased by pre-selecting high-risk individuals.

Characterization of stress processes of Phaffia rhodozyma stress-resistant mutant

A carotenoid-less Phaffia rhodozyma mutant (MCP 325) exhibited significantly higher resistance to oxidative stressors such as menadione, H2O2 and K2Cr2O7 than its astaxanthin-producing parental strain (MCP 324). The absence of carotenoids in the mutant did not explain this phenomenon. The cause of the decreased superoxide, hydroxyl radical and glutathione contents, the increased peroxide concentration and the elevated specific activity of catalase under uninduced conditions may be a second mutation. Peroxide treatment induced specific catalase activity in the mutant but not in the parental strain. Regulation of these processes led to the result that, in spite of the mutations, the two strains exhibited the same multiplication rate and generation time.

[Bleomycin therapy for lymphangioma]

Lymphangiomas are uncommun congenital malformations of the lymphatic system, that involve the skin and subcutaneous tissues. Of the several types of treatment, surgical excision has been the preferred. There is a high recurrence rate because lymphangiomas tend to infiltrate the surrounding tissues. The bleomycin is a cytotoxic antitumoral antibiotic, that causes modifications of DNA. It has been also successfully used in intralesional injection treatment of cystic hygromas and haemangiomas, based specifically on a high sclerosing effect on vascular endothelium. We report the cases of five patients, with congenital lymphangioma, localized on the leg, in cervical and latero-thoracal region, treated with repeated intralesional bleomycin injections. The treatment indication was given by the location of this lesions and the infiltration of the surrounding vital tissues, that made the complete surgical excision impossible. Intralesional injection of bleomycin into the lymphangiomas was given at a dose, not exceeding 0,5 mg/kg of body weight, at intervals of 4 weeks. Complete resolution (n = 4) or significant improvement (n = 1) occurred in all patients treated. No other treatment was needed. We didn't notice local or general adverse effects. With this method we set the purpose to treat effectively this congenital malformations, obviating the need for invasive primary surgery or systemic treatment regimens. Toward other methods, intralesional bleomycin injections have a minimal risk of side effects (ulceration, pulmonary fibrosis).

Role of diagnosis of dyslipidemia in primary and secondary vascular prevention in a neurology department

Lipids have important functions in the human body, but high serum cholesterol level is an important risk factor for cardiovascular and cerebrovascular diseases. Prevention of stroke includes modifying risk factors, like dyslipidemias. Based on this theory, we examined in practice the possible role of a public care neurology and stroke department with a large patient turnover in vascular risk screening with regard to the diagnosis of hyperlipidemia. We reviewed all the medical records (irrespective of disease group;) of patients hospitalized in 2007 at Department of Neurclogy and Stroke Center of Szent János Hospital of the Municipality of the City of Budapest. Patients included in the study were classified into three groups: (1) those admitted with acute stroke; (2) those with a history of acute stroke, but without evidence of a novel cerebrovascular event; (3) no history and evidence of cerebrovascular disease during hospitalization. Our data show that 17.6% of patients was diagnosed with hyperlipidemia during hospital care, and another 18.5% was known to have elevated cholesterol levels. Altogether, 36.1% of the 1438 patients evaluated had hyper ipidemia. Known hypercholesterolemia was 18.4% in patierts admitted for acute stroke, 26.9% in patients formerly (but not currently) treated for cerebrovascular disease, and 13.6% in the third group. Newly diagnosed elevated cholesterol levels had highest rate (22.6%) in former stroke patierts (currently treated for other diseases); 20.4% in patients with acute stroke, and 13.2% in the third group. In the first two groups, the number of patients newly diagnosed with elevated serum cholesterol almost equaled to those with already known hypercholesterolemia. Based on our data, neurology departments have an important role in diagnosing hyperlipidemia and vascular prevention.

Bioinspired artificial photonic nanoarchitecture using the elytron of the beetle Trigonophorus rothschildi varians as a 'blueprint'

An unusual, intercalated photonic nanoarchitecture was discovered in the elytra of Taiwanese Trigonophorus rothschildi varians beetles. It consists of a multilayer structure intercalated with a random distribution of cylindrical holes normal to the plane of the multilayer. The nanoarchitectures were characterized structurally by scanning electron microscopy and optically by normal incidence, integrated and goniometric reflectance measurements. They exhibit an unsaturated specular and saturated non-specular component of the reflected light. Bioinspired, artificial nanoarchitectures of similar structure and with similar properties were realized by drilling holes of submicron size in a multilayer structure, showing that such photonic nanoarchitectures of biological origin may constitute valuable blueprints for artificial photonic materials.

Role of S-methylmethionine in the plant metabolism

S-methylmethionine (SMM), a naturally occurring, biologically active compound, is a free amino acid derivative, which is increasingly recognised as playing an important part in the plant metabolism. SMM, which is synthesised from methionine, is involved in crucial processes in the S metabolism, such as the regulation of methionine and S-adenosyl methionine levels, the methylation processes taking place in cells, and the transport and storage of sulphur in certain phases of development. It is of great importance in the development of resistance to abiotic and biotic stress factors, as it is a direct precursor in the biosynthesis of the osmoprotectants and other S-containing compounds involved in defence mechanisms, while also influencing the biosynthesis of major plant hormones such as polyamines and ethylene. The present paper discusses our increasing understanding of the role played by SMM in the plant metabolism and its possible role in the improvement of traits that enable plants to overcome stress.

Activation of poly(ADP-ribose) polymerase by myocardial ischemia and coronary reperfusion in human circulating leukocytes

Reactive free radical and oxidant production leads to DNA damage during myocardial ischemia/reperfusion. Consequent overactivation of poly(ADP-ribose) polymerase (PARP) promotes cellular energy deficit and necrosis. We hypothesized that PARP is activated in circulating leukocytes in patients with myocardial infarction and reperfusion during primary percutaneous coronary intervention (PCI). In 15 patients with ST segment elevation acute myocardial infarction, before and after primary PCI and 24 and 96 h later, we determined serum hydrogen peroxide concentrations, plasma levels of the oxidative DNA adduct 8-hydroxy-2'-deoxyguanosine (8OHdG), tyrosine nitration, PARP activation, and translocation of apoptosis-inducing factor (AIF) in circulating leukocytes. Plasma 8OHdG levels and leukocyte tyrosine nitration were rapidly increased by PCI. Similarly, poly(ADP-ribose) content of the leukocytes increased in cells isolated just after PCI, indicating immediate PARP activation triggered by reperfusion of the myocardium. In contrast, serum hydrogen peroxide concentrations and the translocation of AIF gradually increased over time and were most pronounced at 96 h. Reperfusion-related oxidative/nitrosative stress triggers DNA damage, which leads to PARP activation in circulating leukocytes. Translocation of AIF and lipid peroxidation occurs at a later stage. These results represent the first direct demonstration of PARP activation in human myocardial infarction. Future work is required to test whether pharmacological inhibition of PARP may offer myocardial protection during primary PCI.

Activation of poly(ADP-ribose) polymerase by myocardial ischemia and coronary reperfusion in human circulating leukocytes

Reactive free radical and oxidant production leads to DNA damage during myocardial ischemia/reperfusion. Consequent overactivation of poly(ADP-ribose) polymerase (PARP) promotes cellular energy deficit and necrosis. We hypothesized that PARP is activated in circulating leukocytes in patients with myocardial infarction and reperfusion during primary percutaneous coronary intervention (PCI). In 15 patients with ST segment elevation acute myocardial infarction, before and after primary PCI and 24 and 96 h later, we determined serum hydrogen peroxide concentrations, plasma levels of the oxidative DNA adduct 8-hydroxy-2'-deoxyguanosine (8OHdG), tyrosine nitration, PARP activation, and translocation of apoptosis-inducing factor (AIF) in circulating leukocytes. Plasma 8OHdG levels and leukocyte tyrosine nitration were rapidly increased by PCI. Similarly, poly(ADP-ribose) content of the leukocytes increased in cells isolated just after PCI, indicating immediate PARP activation triggered by reperfusion of the myocardium. In contrast, serum hydrogen peroxide concentrations and the translocation of AIF gradually increased over time and were most pronounced at 96 h. Reperfusion-related oxidative/nitrosative stress triggers DNA damage, which leads to PARP activation in circulating leukocytes. Translocation of AIF and lipid peroxidation occurs at a later stage. These results represent the first direct demonstration of PARP activation in human myocardial infarction. Future work is required to test whether pharmacological inhibition of PARP may offer myocardial protection during primary PCI.

Comparative detection of high-risk HPV (16, 18, 33) in cervical bioptic material of county hospital of Tg. Mures

The purpose of this study was to collect data about the incidence of high-risk HPV (16, 18, 33) types in paraffin embedded cervical bioptic material, including LSIL, HSIL and cervical cancers using immunohistochemistry and nested PCR methods. In our study were included randomly selected 10 LSIL, 18 HSIL and 30 cervical cancer cases. We analyzed the expression of HPV in this specimens with immunohistochemistry used DAKO K1H8 antibody and CHEMICON Mab HPV 16, 16 antibody using LSAB method and Tiramin amplification method, and nested PCR for HPV 16, 18 and 33. In LSIL cases three, in HSIL cases eight and in carcinoma 20 cases were positive for HPV 16 or 18 for immunohistochemistry or PCR. Although this proportion in lower than those reported in the literature, our work signals the existence of the infection in our country and presents a relatively cheap diagnostic method.

Investigations on the adaptability of maize lines and hybrids to low temperature and cadmium

In the course of the Maize Consortium Project, investigations were made on the defence mechanisms employed by maize against various abiotic stress factors (low temperature, cadmium) and on the effects exerted by two compounds (S-methylmethionine, salicylic acid) capable of improving the stress resistance of plants to certain abiotic stresses. Salicylic acid (SA) was found to inhibit the uptake of cadmium (Cd), but caused damage to the roots, including a reduction in the activity of phytochelatin synthase (PCS), which meant that preliminary treatment with SA aggravated the damaging effect of Cd. It was also proved that as the result of 2-day treatment with Cd, there was a continuous rise in the Cd level in the plants, more Cd being accumulated in young leaves than in older ones. The PCS activity increased greatly after 24 hours, both in the leaves and in the roots, declining again after 2 days. The effect of SA was examined in both the hybrids and their parental lines, and the effect of this compound on the intensity of alternative respiration was also investigated. A comparison of chilling tolerance data and antioxidant enzyme activity indicated that these two parameters were not directly correlated to each other, i.e. antioxidant enzyme activity values could not be used to draw reliable conclusions on the chilling tolerance of maize lines and hybrids. With regard to the interaction between alternative respiration and salicylic acid, it was proved that exogenous hydrogen peroxide caused a similar increase in the ratio of alternative respiration to that observed after salicylic acid treatment. Abbreviations: SA, salicylic acid; Cd, cadmium; PCS, phytochelatin synthase; SMM, S-methylmethionine; PCs, phytochelatins; PAR, photosynthetically active radiation; TTC, triphenyl tetrazolium chloride; KCN, potassium cyanide; PSII, 2nd photochemical system; POD, guaiacol peroxidase; APX, ascorbate peroxidase; GR, glutathione reductase

Haemorrhagic nephritis and enteritis of geese: pathomorphological investigations and proposed pathogenesis

Haemorrhagic nephritis and enteritis of geese as a new disease was first described in Hungary in 1969. The authors identified the causative agent of the outbreaks occurring in 1969 as a polyomavirus by PCR in 2001. In order to study the pathogenesis of the virus, one-day-old goslings were infected with tissue homogenate that tested positive for polyomavirus by PCR. Morphological, light and transmission electron microscopic (TEM) examinations have revealed that goose haemorrhagic polyomavirus replicates in the endothelial cells of the blood vessels and capillaries of diseased birds. Infection causes damage and necrosis of the endothelial cells. The virus was not observed in the parenchymal cells. Oedema and haemorrhages found throughout the body may be due to the dysfunction or functional deficiency of endothelial cells damaged by the virus.

Effect of propranolol on heart rate variability in patients with end-stage renal disease: a double-blind, placebo-controlled, randomized crossover pilot trial

BACKGROUND

Low heart rate variability (HRV) is an independent risk factor of cardiac mortality in patients with end-stage renal disease (ESRD). It has been explained by uremic parasympathetic neuropathy. Sympathetic overactivity can also reduce HRV. Our aim was to determine whether there is vagal activity in ESRD patients that is masked by sympathetic activity.

METHODS

The effect of propranolol on HRV was examined in 13 patients with ESRD, aged 20.1 +/- 7.6 years without diabetes. All patients were given intravenous propranolol (0.05 mg/kg) once and placebo once in a randomized, double-blind way, with an interval of 6.6 days (mean, range: 2-9). Propranolol was administered before hemodialysis treatment, after 40 minutes supine resting period. HRV was registered for 10 minutes, during supine, before and after the injection. Patients' HRV data were compared to that of 29 age-matched healthy controls.

RESULTS

Initially, both high-(HFV) and low-frequency (LFV) bands of heart rate variability were lower in ESRD patients compared to controls (p < 0.001 for both). Propranolol resulted in a significant increase of HFV (propranolol: AlgHFV = 0.182 (0.027 - 0.337), placebo: deltalgHFV = -0.029 (-0.128 - +0.070); p = 0.032). Elevation of LFV was not significant. Six patients had an elevated plasma norepinephrine and/or epinephrine level. Plasma dopamine level was elevated in all but 1 patient (mean: 432 pmol/l, 95% CI: 320-543) and showed an inverse relationship with the increase of IgHFV secondary to propranolol (r = -0.66, p = 0.014).

CONCLUSIONS

Low HFV of ESRD patients can be improved by beta-adrenergic blockade. It demonstrates that there is some vagal activity in ESRD that is masked by sympathetic activity. Therefore, altered sympathovagal balance of ESRD patients should be taken into consideration in the assessment of vagal uremic neuropathy.

A synthetic derivative of the natural product rocaglaol is a potent inhibitor of cytokine-mediated signaling and shows neuroprotective activity in vitro and in animal models of Parkinson's disease and traumatic brain injury

Many acute and chronic neurodegenerative diseases are characterized by a localized inflammatory response and constitutive activation of the transcription factors nuclear factor-kappa B (NF-kappa B) and activator protein-1 (AP-1) as well as their upstream activating signaling cascades. Ample evidence indicates the implication of these processes in the pathogenesis of several diseases of the central nervous system. In this study, we show that a synthetic derivative of the natural product rocaglaol (compound A) displays potent anti-inflammatory properties in human endothelial and murine glial cells in vitro. Compound A inhibited cytokine- and lipopolysaccharide-induced release of various cytokines/chemokines and of nitric oxide as well as expression of the adhesion molecule endothelial leukocyte adhesion molecule-1 and the inducible enzymes nitric-oxide synthase and cyclooxygenase-2. As shown by immunocytochemistry and immunoblotting, compound A inhibited NF-kappa B and AP-1 activity in mixed glial cultures. Compound A exhibited neuroprotective activity in vitro and in vivo. 1-Methyl-4-phenylpyridinium-induced damage of mesencephalic dopaminergic neurons was significantly decreased, and long-term treatment of 1-methyl-4-phenyl-1,2,3,6,-tetrahydropyridine-injected mice with compound A significantly and dose-dependently reduced dopaminergic neuronal cell death. In addition, shortterm application of compound A to rats suffering from traumatic brain injury induced by subdural hematoma resulted in a significant reduction of the cerebral infarct volume. These results suggest that by inhibiting NF-kappa B and AP-1 signaling, compound A is able to reduce tissue inflammation and neuronal cell death, resulting in significant neuroprotection in animal models of neurodegeneration.

Neural stem cell transplantation in cold lesion: a novel approach for the investigation of brain trauma and repair

We developed a new neural transplantation protocol for the investigation of the repair of brain trauma. Cortical lesion was induced by touching a cold (-60 degrees C) metal stamp to the dura over the forelimb motor cortex of adult rats. The procedure caused a localized lesion and the animals developed a significant motor deficit, which was monitored throughout the protocol. Six days later the animals received embryonic neural stem cells in the penumbra of the lesion. The donor cells were freshly isolated from E14 rat embryos, had a high viability, and expressed the stem cell marker nestin. A further 6 days later the survival and differentiation of the grafted cells were investigated by immunohistochemistry. The majority of the surviving grafted cells were found in the lesion and they did not express lineage-specific markers. Only 10% of all surviving transplanted cells were located in the penumbra. These cells had an astrocytic phenotype and expressed glial fibrillary acidic protein. A few cells expressed neural or oligodendrocytic markers. In conclusion, we established a novel neural transplantation protocol, which focuses on cortical brain trauma. The model is a combination of surgical, neurological and histological approaches, all adapted to each other to make a reliable and reproducible experimental model.