Differential expression of Snail1 transcription factor and Snail1-related genes in alveolar and embryonal rhabdomyosarcoma subtypes

Rhabdomyosarcoma (RMS) represents the most common sarcoma of soft tissue among children. Two main RMS subtypes are alveolar (ARMS) and embryonal (ERMS). The major goal of this study was to find differentially expressed genes between RMS subtypes that could explain higher metastatic potential in ARMS and would be useful for the differential diagnosis. Using RQ-PCR analysis we compared expression of Snail1 and Snail-related genes among 7 ARMS and 8 ERMS patients' samples obtained from the primary tumors and among 2 alveolar and 2 embryonal cell lines. Our results show that Snail1 is highly expressed both in ARMS patients' samples and the alveolar cell lines. We also found that the expression of E-Cadherin was downregulated and the expression of Matrix Metalloproteinases 2 and 9 (MMP-2 and MMP-9) was upregulated in ARMS. We assume that, as in many tumors, also in RMS Snail1 acts as a regulator for pathways known for their role in cells' metastasis and that Snail1 activity results in increased MMPs and decreased E-Cadherin expression. Our findings may explain higher ARMS aggressiveness. Moreover, we suggest that further studies should be performed to verify if Snail1 can be considered as a potential target for ARMS therapy.     

Extracellular phospholipases in atherosclerosis

Phospholipases A2 (PLA2) are a family of enzymes that catalyze the hydrolysis of the sn-2 ester bond of glycerophospholipids liberating lysophospholipids and free fatty acids; important second messengers involved in atherogenesis. Plasma PAF-acetylhydrolase (PAF-AH) or Lp-PLA2 is a Ca²⁺-independent PLA2 which is produced by monocyte-derived macrophages and by activated platelets, and circulates in plasma associated with lipoproteins. PAF-AH catalyzes the removal of the acetyl/short acyl group at the sn-2 position of PAF and oxidized phospholipids produced during inflammation and oxidative stress. In humans, PAF-AH is mainly associated with small dense LDL and to a lesser extent with HDL and with lipoprotein(a). PAF-AH is N-glycosylated prior to secretion which diminishes its association with HDL raising the question of its distribution between the proatherogenic LDL vs the antiatherogenic HDL. Hypercholesterolemic patients have higher plasma PAF-AH activity which is reduced upon hypolipidemic therapy. PAF-AH specific inhibitor darapladib stabilizes human and swine plaques, therefore challenging the antiatherogenic potential of PAF-AH shown in small animal models.     

Distribution of motor unit potential velocities in the biceps brachii muscle of sprinters and endurance athletes during prolonged dynamic exercises at low force levels

In surface electromyography (sEMG), the distribution of motor unit potential (MUP) velocities has been shown to reflect the proportion of faster and slower propagating MUPs. This study investigated whether the distribution of MUP velocities could distinguish between sprinters (n = 11) and endurance athletes (n = 12) in not-specifically trained muscle (biceps brachii) during prolonged dynamic exercises at low forces. sEMG was acquired during 4 min’ exercises: unloaded, 5%, 10% and 20% of maximal voluntary contraction (MVC). The features extracted from the sEMG were: the mean muscle conduction velocity – estimated using the inter-peak latency and cross-correlation methods, the within-subject skewness (expressing the proportions of faster and slower propagating MUPs) and the within-subject standard deviation of MUP velocities (SD-mup). Sprinters showed a greater proportion of faster propagating MUPs than endurance athletes. During fatigue, the SD-mup of sprinters broadened progressively, whereas that of endurance athletes did not. The findings suggest that sprinters conveyed a greater proportion of faster motor units than endurance athletes and that motor unit behavior during fatigue differed between groups. Thus, the distribution of MUP velocities enables distinction between a muscle of sprinters and endurance athletes during prolonged dynamic exercises at low forces.     

Distribution of motor unit potential velocities in the biceps brachii muscle of sprinters and endurance athletes during short static contractions at low force levels

In surface electromyography (sEMG), the distribution of motor unit potential (MUP) velocities has been shown to reflect the proportion of faster and slower propagating MUPs. This study investigated whether the distribution of MUP velocities could distinguish between sprinters and endurance athletes in not-specifically trained muscle (biceps brachii). sEMG results were acquired from 15 sprinters and 18 endurance athletes during short static contractions (3.8 s) at three force levels: unloaded, 10% and 20% of maximum voluntary contraction. The features extracted from the sEMG were: the mean muscle conduction velocity (CV) – estimated using the inter-peak latency and the cross-correlation methods, the within-subject skewness of MUP velocities (expressing the relative proportions of faster and slower propagating MUPs), and the within-subject standard deviation of MUP velocities. Sprinters had a higher CV than endurance athletes using both methods. Sprinters also demonstrated a greater proportion of fast propagating MUPs, as indicated by the skewness. Thus, the distribution of MUP velocities was able to demonstrate physiological differences between sprinters and endurance athletes during short contractions at low forces. The findings can be extrapolated to the motor unit level. Since the investigated muscle was not involved in specific training, the differences seem to reflect inherited properties.     

In vitro antiproliferative and antifungal activity of essential oils from Erigeron acris L. and Erigeron annuus (L.) Pers

Antiproliferative and antifungal activities of essential oils from Erigeron acris root and herb and from Erigeron annuus herb were investigated. The cell viability assay was performed in cultured fibroblasts, cancer cell lines (MCF-7 and MDA-MBA-231), and endometrial adenocarcinoma (Ishikawa) cells as well as colon adenocarcinoma (DLD-1) cells using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). The essential oil from E. acris root showed the highest antiproliferative activity in the MCF-7 cell line with an IC50 value of 14.5 microg/mL. No effect of the essential oil on normal cells at that concentration was found. Antifungal activity against various strains of five Candida species, i.e. C. albicans, C. glabrata, C. tropicalis, C. krusei, and C. parapsilosis, was tested by the microdilution method. It was found that all examined oils can be useful as antifungal agents against the above-mentioned species, but the essential oil of E. acris herb was the most active. Their minimum inhibitory concentrations (MIC) ranged from 30 to 0.4 microL/mL. The data presented suggest that essential oils from E. acris and E. annuus possess antifungal activity against Candida spp. and antiproliferative activity against breast cancer MCF-7 cells.     

Influence of Methionine upon the Activity of Antioxidative Enzymes in The Kidney of Rats Exposed to Sodium Fluoride

The intensified or uncontrolled formation of reactive oxygen species leads to disturbances of numerous biochemical processes. Among the factors inducing intensified free radical processes, fluoride ions are listed, among others. One of the organs most exposed to the toxic activity of fluorides is the kidney. In the study presented here, the influence of fluorine upon the activity of selected antioxidant enzymes in rat kidney has been examined, as well as antioxidant properties of methionine during intoxication with sodium fluoride. The experiment was carried out on Wistar FL rats (adult females) that for 35 days were administered water, NaF, NaF with methionine (doses: 10 mg NaF/kg bw/day, 10 mg Met/kg bw/day) . The influence of administered NaF and Met upon the antioxidative system in kidney was examined by analyzing the activity of the most important antioxidative enzymes (SOD, CAT, GPX, GR, GST). The studies carried out confirmed the disadvantageous effect of NaF upon the antioxidative system in rats (decrease in activity of antioxidative enzymes). Methionine increased the activity of antioxidative enzymes, most efficiently that of GPX, GR, and GST.     

Fluorescent homogeneous immunosensors for detecting pathogenic bacteria

We developed a straightforward antibody-based assay for rapid homogeneous detection of bacteria. Our sensors utilize antibody recognizing cell-surface epitopes of the target cell. Two samples of the antibody are prepared, each labeled via nanometer size flexible linkers with short complementary oligonucleotides that are modified with fluorochromes that could participate in fluorescence resonance energy transfer (FRET). The length of the complementary oligonucleotide sequences was designed such that very little annealing occurred in the absence of the target cells. In the presence of the target cells the two labeled antibodies bind to the surface of the cell resulting in a large local concentration of the complementary oligonucleotides that are attached to the antibody. This in turn drives the annealing of the complementary oligonucleotides which brings the fluorescence probes to close proximity producing large FRET signals proportional to the amount of target cells. Long flexible linkers used to attach the oligonucleotides to the antibody enable target-induced oligonucleotide annealing even if the density of surface antigens is only modest. We used Escherichia coli 0157:H7 and Salmonella typhimurium to demonstrate that this design produced sensors exhibiting rapid response time, high specificity, and sensitivity in detecting the target bacteria.     

Impact of a small cormorant (Phalacrocorax carbo sinensis) roost on nutrients and phytoplankton assemblages in the littoral regions of a submontane reservoir

Cormorants (median numbers of 54.5 ind.) excreted ca. 102.7 kg yr⁻¹ of nitrogen and ca. 80.5 kg yr⁻¹ of phosphorus in the area of the Dobczyce Reservoir (ca. 980 ha). Concentrations of N-tot and P-tot were 3 times higher in soil from the roosting area of the cormorants than outside this area. Nutrient concentrations in the littoral sediment of the reservoir were also higher in the area frequented by these birds. Differences in concentrations of pH, NO₃⁻, NO₂⁻, NH₄⁺, PO₄⁻, and P-tot in water between the area associated with the cormorants and the reference site were not found. Differences in the planktonic algal communities from around the roost and the reference site were not found, with the exception of the chlorophytes which were more abundant in the area occupied by the cormorants. Water movement and mixing in the reservoir can influence the effect of the nutrient load on the water chemistry and planktonic algae.     

Genotype–phenotype correlations in Leber hereditary optic neuropathy

Leber hereditary optic neuropathy (LHON), acute or subacute vision loss due to retinal ganglion cell death which in the long run leads to optic nerve atrophy is one of the most widely studied maternally inherited diseases caused by mutations in mitochondrial DNA. Although three common mutations, 11778G>A, 14484T>C or 3460G>A are responsible for over 90% of cases and affect genes encoding complex I subunits of the respiratory chain, their influence on bioenergetic properties of the cell is marginal and cannot fully explain the pathology of the disease. The following chain of events was proposed, based on biochemical and anatomical properties of retinal ganglion cells whose axons form the optic nerve: mitochondrial DNA mutations increase reactive oxygen species production in these sensitive cells, leading to caspase-independent apoptosis. As LHON is characterized by low penetrance and sex bias (men are affected about 5 times more frequently than women) the participation of the other factors—genetic and environmental—beside mtDNA mutations was studied. Mitochondrial haplogroups and smoking are some of the factors involved in the complex etiology of this disease.     

Oxidative stress-dependent p66Shc phosphorylation in skin fibroblasts of children with mitochondrial disorders

p66Shc, the growth factor adaptor protein, can have a substantial impact on mitochondrial metabolism through regulation of cellular response to oxidative stress. We investigated relationships between the extent of p66Shc phosphorylation at Ser36, mitochondrial dysfunctions and an antioxidant defense reactions in fibroblasts derived from five patients with various mitochondrial disorders (two with mitochondrial DNA mutations and three with methylglutaconic aciduria and genetic defects localized, most probably, in nuclear genes). We found that in all these fibroblasts, the extent of p66Shc phosphorylation at Ser36 was significantly increased. This correlated with a substantially decreased level of mitochondrial superoxide dismutase (SOD2) in these cells. This suggest that SOD2 is under control of the Ser36 phosphorylation status of p66Shc protein. As a consequence, an intracellular oxidative stress and accumulation of damages caused by oxygen free radicals are observed in the cells.