T cells and their function in the immune response to viruses.

The development of CD4+ T helper cells is determined by the set of transcription factors and the genes these transcription factors transcribe. In this review, we describe the basic nature of Th1, Th2, Th9, Th17, T-follicular helper (Tfh), gamma delta (γδ) T cells, and T-regulatory (Treg) cells subsets, their master regulator transcription factors and their corresponding signature cytokine production profiles. Cellular immunity plays important role during virus infection. Optimal immune response to viral infections require a gentle balance of effector responses to clear the infected cells and regulatory mechanism to prevent  immunopathology. The behavior of the helper cells differs with each virus - while in some cases, the response is beneficial; in other cases, it is harmful. We discuss the protective and pathological role of T cell immunity against influenza A virus (IAV), respiratory syncytial virus (RSV), immunodeficiency virus type 1 (HIV-1), and hepatitis B virus (HBV) infection. Keywords: T cell; cytokine; influenza virus; respiratory syncytial virus; hepatitis B virus; human immunodeficiency virus type 1.

Influenza A virus lacking the effector and C terminal domains of NS1 protein induces cytokines associated with high pathogenicity in mice.

Non-structural NS1 protein of influenza A virus counters host antiviral defences by antagonizing the interferon response. The C-terminal effector domain suppresses the host response and is associated with the pathogenicity of the virus.  To better understand the regulatory role of the C-terminal domain, we used reverse genetics system to generate NS1-truncated virus (NS80) and compared the cytokine profiles in the lungs of mice infected with the NS80 mutant and with the control virus A/WSN/33 (WSN). The NS80 virus was attenuated and the viral titer in the lungs was about 25 times lower than viral titer of control A/WSN/33. Mice infected with NS80 virus exhibited more severe clinical symptoms and 2 mice died 6 days post infection. NS80 virus activated retinoic-inducible gene (RIG)-1-like receptor signaling pathway more strongly than control WSN virus and mice infected with NS80 virus exhibited a greater abundance and more diverse cytokine profile.  Infection with NS80 virus induced the expression of the following factors: pro-inflammatory cytokines (IL-1α, IL-1ß, TNF-α, IL-16), interferons (IFN-α and IFN-ε), chemokines (CCL2, CCL11, CXCL1, CXCL5, CXCL10, CXCL11 and CXCL13), matrix metallopeptidase 9 (MMP-9), metallopeptidase inhibitor 1 (TIMP-1), macrophage colony-stimulating factor (M-CSF), and vascular cell adhesion protein 1 (VCAM-1). All these cytokines are associated with viral pathogenicity. Our data show that attenuation of the virus should not be directly linked with pathogenicity. Keywords: influenza virus; NS1 protein; cytokines; interferon; pathogenicity.

Age-dependent effect of long-term microwave radiation on postnatal neurogenesis in rats: morphological and behavioral study.

Processes of adult neurogenesis can be influenced by environmental factors. Here, we investigated the effect of microwave radiation (MWR) on proliferation and cell dying in the rat rostral migratory stream (RMS) - a migration route for the neuroblasts of the subventricular zone. Adult and juvenile (two weeks old) rats were exposed to a pulsed-wave MWR at the frequency of 2.45 GHz for 1 or 3 h daily during 3 weeks. Adult rats were divided into two groups: without survival and with two weeks survival after irradiation. Juvenile rats survived till adulthood, when were tested in the light/dark test. Proliferating cells in the RMS were labeled by Ki-67; dying cells were visualized by Fluoro-Jade C histochemistry. In both groups of rats irradiated as adults we have observed significant decrease of the number of dividing cells within the RMS. Exposure of juvenile rats to MWR induced only slight decrease in proliferation, however, it strikingly affected cell death even two months following irradiation. In addition, these rats displayed locomotor hyperactivity and decreased risk assessment in adulthood. Our results suggest that the long-lasting influence of radiation is manifested by affected cell survival and changes in animals´ behavior.

Gamma Radiation Reduced Toxicity of Azoxystrobin Tested on Artemia franciscana.

Fungicide azoxystrobin toxicity was monitored by means of a 96-h biotest with Artemia franciscana nauplius stages after exposure to solutions with concentrations of 0.2, 0.4, 0.6 and 0.8 mg L(-1) irradiated with (60)Co gamma radiation with doses of 1, 2.5, 5 and 10 kGy. The effects of ionization radiation on azoxystrobin toxicity were mainly manifested by a statistically significant reduction of lethality after 72- and 96-h exposure. A maximum reduction of lethality of 72 % was achieved using doses of 1-5 kGy for an azoxystrobin initial concentration of 0.4 mg L(-1) and after 72 h of exposure. At a 96-h exposure, a difference of lethal effects reached up to 70 % for a dose of 10 kGy. The observed effect of gamma ionizing radiation on azoxystrobin toxicity suggest that this approach can be applied as an alternative for a reduction of azoxystrobin residua in food.

Structural and ultrastructural study of rat liver influenced by electromagnetic radiation.

Mobile communication systems are undoubtedly an environmental source of electromagnetic radiation (EMR). There is an increasing concern regarding the interactions of EMR with the humans. The aim of this study was to examine the effects of EMR on Wistar rat liver. Mature rats were exposed to electromagnetic field of frequency 2.45 GHz and mean power density of 2.8 mW/cm2 for 3 h/d for 3 wk. Samples of the liver were obtained 3 h after the last irradiation and processed histologically for light and transmission electron microscopy. Data demonstrated the presence of moderate hyperemia, dilatation of liver sinusoids, and small inflammatory foci in the center of liver lobules. Structure of hepatocytes was not altered and all described changes were classified as moderate. Electron microscopy of hepatocytes revealed vesicles of different sizes and shapes, lipid droplets, and proliferation of smooth endoplasmic reticulum. Occasionally necrotizing hepatocytes were observed. Our observations demonstrate that EMR exposure produced adverse effects on rat liver.

DNA detection of Toxoplasma gondii in sheep milk and blood samples in relation to phase of infection.

Toxoplasma gondii is a worldwide parasite that is important both for veterinary medicine (economic losses in the herd) and for public health (immunocompromised patients and pregnant women). An important source of Toxoplasma infection in humans is consumption of contaminated meat and milk (undercooked meat and unpasteurized milk). Small ruminants are important in both milk and meat production throughout the world because of free-range husbandry. The purpose of our study was to detect the presence of T. gondii DNA in ewes' milk 1 month after the term, and to determine the relationship between the occurrence of this DNA in blood and milk based on the phase of infection. Using enzyme-linked immunosorbent assay (ELISA) the animals were divided into two groups (immunoglobulin M positive (IgM+), IgM-). With real-time polymerase chain reaction (PCR), T. gondii DNA was detected in seven milk samples (28%) and five blood samples (20%) of the IgM+ group (25 samples). In the IgM- group T. gondii DNA was detected in two milk samples (3.6%) out of 55 samples.

Selected morphological changes in Artemia franciscana after ionizing radiation exposure.

Nauplii of Artemia franciscana were irradiated by the doses of 0.25, 0.5, 1.0, and 2.5 kGy (60)Co. Dimensions of the body length, body width, intestine width, intestine epithelium width, and intestine lumen width, as well as the mutual ratios of dimensions were determined in 126 specimens. Ratios of the body length/body width (3.98, 3.60, 3.59, and 3.45 vs. 4.13 of control group), and ratios of the intestine epithelium width/intestine lumen width (0.64, 0.52, 0.51, and 0.45 vs. 0.85 of control group), according to the doses, were the most important parameters of evaluation of dependence of morphological changes on radiation doses.

Induction of micronuclei in rat bone marrow after chronic exposure to lead acetate trihydrate.

Lead increasingly contributes to pollution of the environment and may play a role in the development of adverse effects in the human and animal body. Data concerning its mutagenic, clastogenic, and carcinogenic properties have been conflicting. In this study, we evaluated the frequency of micronuclei in bone marrow erythrocytes of rats treated with lead acetate trihydrate. Outbred Wistar rats were exposed to a daily dose of 100 mg/L drinking water for 125 days. The mean value of the total number of micronuclei observed in polychromatic erythrocytes of female rats was significantly higher than that found in the control group (13.375 +/- 2.722 against 9.625 +/- 3.204 micronuclei/1000 cells; P = 0.024 in ANOVA). In exposed female animals, no significant reduction of the ratio of polychromatic to normochromatic erythrocytes was observed (0.990 +/- 0.228 against 1.208 +/- 0.195; P = 0.060 in ANOVA). The effects of lead acetate trihydrate in male rats are both cytotoxic and genotoxic because of a decrease in ratio of polychromatic to normochromatic erythrocytes (0.715 +/- 0.431 against 1.343 +/- 0.306; P = 0.023, ANOVA followed by Tukey test) and an increase in frequency of micronucleated polychromatic erythrocytes (24.167 +/- 7.859 against 4.0 +/- 4.528 micronuclei/1000 cells; P < or = 0.001, ANOVA followed by Tukey test), respectively.

Radiocesium activity reduction in boar meat by brining.

Meat of wild boar with an intial (137)Cs activity concentration of 103 Bq kg(-1) of fresh mass was treated by brining. Dry-salting reduced the (137)Cs activity only by about 12-18%. Subsequent brining was done by using both pure sodium chloride and a mixture of sodium chloride and potassium nitrate. After double-brine exchange, the (137)Cs activity concentration was reduced by at least 72%. The double-brine exchanges were done for two time intervals (the first each 24 h and the second each 7 days). There were no differences in the (137)Cs activity reduction for these two time intervals. From the technological point of view, the repeated exchange of the brine solution represents a relative easy method of (137)Cs activity reduction in contaminated pork meat.

Influence of a single gamma-irradiation on rat microflora.

Changes in leukocyte counts and in the gut microflora of laboratory rats irradiated with single whole-body dose of gamma rays (5.0 Gy) were determined. The number of leukocytes was lower especially 1 and 2 weeks after irradiation. A significant decrease in lymphocytes was observed 1 week and in monocytes 1 and 2 weeks after irradiation. In parallel with these changes, an increase in common microflora was observed; some microorganisms, which normally are not present in duodenum, liver and mouth cavity, were detected in these organs.

Acute oral toxicity of the herbicide BUREX EKO in pheasants.

The aim of this study was to determine the acute LD50, clinical symptoms and pathological changes of acute BUREX EKO intoxication in pheasants according to OECD No 205. Medium lethal dose (LD50) of BUREX EKO in pheasant is 3.84 ml/kg body weight with the upper level of reliability 4.50 ml and lower level of reliability 3.27 ml/kg body weight. As far as the calculation to the effective substance is concerned it is 1077 mg of chloridazone per kg body weight with the interval of reliability from 919 to 1263 mg/kg body weight. Calculated the effective substance of chloridazone (3.84 ml is LD50 of BUREX EKO which contains 1077 mg of chloridazone) BUREX EKO can be classified as the moderately toxic substance to pheasants. There were following clinical symptoms of the BUREX EKO intoxication in pheasants: apathy, drowsiness, incapability to move, ruffled feathers, slight diarrhoea, strenuous respiration, tonico-clonical cramps before death, decease with the head expressively bent rearwards. There was a relatively fast beginning of rigor mortis in dead pheasants. Pathologico-anatomical dissection of the pheasants obtained under conditions of acute intoxication did not reveal any changes on the organs of both experimental and control pheasants which would be immediately connected with the effect of the administered substance. Hyperaemia was recorded by histologico-pathological investigation of the liver and kidneys. No changes on the brain and intestine wall were recorded.

[The effect of prolonged starvation on changes in the activity of selected adaptive enzymes in rat liver]. / Vplyv prolongovaného hladovania na zmeny aktivity vybraných adaptívnych enzýmov v peceni potkanov.

Male rats of Wistar SPF stain (Velaz Prague) were used to investigate the influence of prolonged starvation on changes in the activity of selected adaptive enzymes in the liver and corticosterone in serum. Analyses were carried out on days 1,2,3,5 and 7 of starvation. The activity of tyrosine aminotransferase significantly increased in the period between days 2 and 5 of starvation, after which a decrease to the level of satiated animals was observed in the terminal period. Activities of tryptophane-2-3-dioxygenase and alanine aminotransferase increased in two phases reaching maximum values on days 2 and 7 of starvation. The activity of aspartate aminotransferase showed a progressive significant increase in dependence on the length of starvation. A more than threefold increase in corticosterone concentration was observed in the serum of starved animals in comparison with satiated rats.