Erythrocyte potassium polymorphism in 14 Spanish goat breeds

The existence of polymorphism for erythrocyte potassium (Ke) is confirmed in certain Spanish breeds of goat. A statistical boundary is established between two caprine populations: low (LK) and high (HK) red cell potassium, the dividing line being set at 45 m-equiv/l of Ke. Both types are shown to be controlled genetically by an autosomal locus with two alleles KL and Kh, being KL dominant over Kh. The gene frequencies of KL and Kh are determined in 14 native Spanish breeds of goat.

Genetic relationships between 14 native Spanish breeds of goat

The genetic distances separating 14 Spanish goat breeds are calculated from gene frequency data of 14 genetic blood markers (GSH, Ke, Hb, Dia, Ct, MDH, CA, X, NP, Alp, Am, Cp, Tf and Al). Working from the matrix of Nei's genetic distances we drew a dendrogram demonstrating a great genetic similarity among populations from Negra Serrana, Zamorana, Guadarrama, Retinta, Blanca Andaluza, Berciana and Pirenaica on one hand; and Canaria, Murciana, Blanca Celtibérica, Verata, Palmera, Malagueña and Granadina on the other. We discuss the similarities and differences within our classification using gene frequency data of the blood genetic markers studied, and classifications based chiefly on morphological and production data.

At environmental doses, dietary methylmercury inhibits mitochondrial energy metabolism in skeletal muscles of the zebra fish (Danio rerio)

The neurotoxic compound methylmercury (MeHg) is a commonly encountered pollutant in the environment, and constitutes a hazard for human health through fish eating. To study the impact of MeHg on mitochondrial structure and function, we contaminated the model fish species Danio rerio with food containing 13 microg of MeHg per gram, an environmentally relevant dose. Mitochondria from contaminated zebrafish muscles presented structural abnormalities under electron microscopy observation. In permeabilized muscle fibers, we observed, a strong inhibition of both state 3 mitochondrial respiration and functionally isolated maximal cytochrome c oxidase (COX) activity after 49 days of MeHg exposure. However, the state 4 respiratory rate remained essentially unchanged. This suggested a defect at the level of ATP synthesis. Accordingly, we measured a dramatic decrease in the rate of ATP release by skinned muscle fibers using either pyruvate and malate or succinate as respiratory substrates. However, the amount and the assembly of the ATP synthase were identical in both control and contaminated muscle mitochondrial fractions. This suggests that MeHg induced a decoupling of mitochondrial oxidative phosphorylation in the skeletal muscle of zebrafish. Western blot analysis showed a 30% decrease of COX subunit IV levels, a 50% increase of ATP synthase subunit alpha, and a 40% increase of the succinate dehydrogenase Fe/S protein subunit in the contaminated muscles. This was confirmed by the analysis of gene expression levels, using RT-PCR. Our study provides a basis for further analysis of the deleterious effect of MeHg on fish health via mitochondrial impairment.

Effects of high salinity wastewater on methanogenic sludge bed systems

The attainable loading potentials of anaerobic sludge bed systems are strongly dependent on the growth of granular biomass with a particular wastewater. Experiments were conducted to determine the effects of high salinity wastewater on the biological and physical properties of methanogenic sludge. Sodium concentration of 5 g/L and 15 g/L were added to the influent of upflow anaerobic sludge bed (UASB) systems. After 100 days of operation, the methanogenic activity, extracellular polymeric substances (EPS), and granular strength were analyzed. The results show a high removal of organic matter but with accumulating propionate concentrations in the effluents. Meanwhile, wash-out of active methanogenic biomass in the effluent of the reactors was observed, likely as a results of the high Na+ concentrations. The rinsed biomass was characterized by a considerable specific methanogenic activity (SMA) on acetate, propionate and hydrogen as the substrates. On the other hand, results show that the SMA evolution was not affected by high salt concentrations. Also the amount and composition of extracellular polymeric substances (EPS) were similar in all sludges. However, results clearly show a sharp drop in the granule strength as a results of high Na+ concentration.

Economic evaluation of linezolid versus teicoplanin for the treatment of infections caused by gram-positive microorganisms in Spain

The aim of this study was to perform a comparative cost-effectiveness analysis of linezolid vs teicoplanin (i.v., switching to oral/i.m. respectively) in Spain. A decision tree model was used with the results of a randomized, comparative, controlled clinical trial with linezolid vs teicoplanin in the treatment of infections caused by Gram-positive microorganisms, with a timeline of 31 days. The efficacy endpoint was the percentage of patients with clinical healing or improvement in their infection. Direct medical costs were included using Spanish 2005 prices. Average cost per patient, average cost-effectiveness ratio and several sensitivity analyses were carried out. In the intent-to-treat (ITT) analysis linezolid obtained a higher percentage of therapeutic success than teicoplanin (95.5% vs 87.6% respectively, p = 0.005), both with similar tolerability. The average cost per treated patient was euro 8,064.76 for linezolid vs euro 8,727.36 for teicoplanin, with an incremental cost of euro 622.59 (-7,6%). Linezolid yielded a lower average cost-effectiveness ratio, euro 8,444.78 (8,195.90 - 8,709.25) than teicoplanin, euro 9,962.74 (9,465.68 - 10,502.23), with a slight reduction in average cost per successfully treated patient of 15.2% ( euro 1,517.96). The results were robust to the sensitivity analysis. In conclusion, linezolid is a more cost-effective option than teicoplanin in the treatment of infections caused by Gram-positive microorganisms, since it offers superior clinical benefits with a lower use of associated resources.

Comparative evaluation of the toxicity and genotoxicity of cadmium in amphibian larvae (Xenopus laevis and Pleurodeles waltl) using the comet assay and the micronucleus test

The toxic and genotoxic potential of Cadmium (CdCl(2)) were evaluated by the micronucleus test (MNT) and comet assay (CA) using amphibian larvae (Xenopus laevis and Pleurodeles waltl). Acute toxicity results showed that Cd is toxic to Xenopus larvae exposed from 2 to 50 mg/L and to Pleurodeles from 5 to 50 mg/L, depending on the nature of the water (reconstituted water containing mineral salts or mineral water MW (Volvic)). The MNT results obtained in MW showed that Cd (2 mg/L) is genotoxic to Xenopus, whereas it was not genotoxic to Pleurodeles at all concentrations tested. The CA established that the genotoxicity of Cd to Xenopus and Pleurodeles larvae depends on the concentration, the exposure times, and the comet parameters (Tail DNA, ETM, OTM, and TL). The CA and MNT results were compared for their ability to detect genotoxic effects, considering the concentrations of Cd applied and the exposure time. The CA showed Cd to be genotoxic from the first day of exposure. In amphibians, the CA appears to be a sensitive and suitable method for detecting genotoxicity such as that caused by Cd.

Down-regulation of bbc3, flt1 and gstm3 is associated with lymph node metastases in breast carcinoma

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Background: Background: Axillary lymph node metastasis is the most significant marker for the pathologic staging of breast cancer. However a proportion of lymph node-negative breast cancer will develop metastatic disease. Therefore, molecular markers of invasion in these patients are needed Methods: We selected 10 primary breast cancer cases, 5 lymph node-negative (T1N0) and 4 lymph node-positive (T1N1). In these cases we searched for gene expression of 8 genes (bbc3, cegp1, fgf18, flt1, cffm4, gstm3, hec, tgfb3) selected from previous studies as a good candidates for metastasis prediction. A quantitative Real-Time PCR was performed using beta-2- microglobulin gene expression to normalized gene expression of each gene. The expression average of beta-2-microglobulin was 303,291 among T1N0 and 342,533 among T1N1 cases (ratio 0.88). The expression average of these 8 genes was 2.11 and 0.002 at T1N0 and T1N1 respectively (ratio 1,055). At least 3 genes were significantly down-regulated in T1N1 (bbc3, flt1, gstm3) in comparison with T1N1 breast carcinomas Results: Computational analysis reveals that these 3 genes (bbc3, flt1, gstm3) contain CpG islands in their promoter regions. Although preliminary data, we found group of genes that are down-regulated in T1N1 tumor Conclusions: The finding that these genes are epigenetically regulated, suggest that could be a good candidates for metastasis prediction, by methylation approach (MethyLight System). Since this down-regulation occurs in primary tumor, the analysis of these genes might be useful to predict metastasis in lymph node-negative breast cancer.

No significant financial relationships to disclose.

Challenging the model for induction of metallothionein gene expression

Metallothioneins (MTs) are low-molecular-weight, cysteine-rich metal-binding proteins found in a wide variety of organisms including bacteria, fungi and all eukaryotic plant and animal species. MTs bind essential and non-essential heavy metals. In mammalian cells MT genes are highly inducible by many heavy metals including Zn, Cd, Hg, and Cu. Aquatic systems are contaminated by different pollutants, including metals, as a result of man's activities. Bivalve molluscs are known to accumulate high concentrations of heavy metals in their tissue and are widely used as bioindicators for pollution in marine and freshwater environments, with MTs frequently used as a valuable marker of metal contamination. We here describe the MT isoform gene expression patterns of marine and freshwater molluscs and fish species after Cd or Zn contamination. Contamination was carried out at a river site polluted by a zinc ore extraction plant or in the laboratory at low, environmentally relevant metal concentrations. A comparison for each species based on the accumulated MT protein levels often shows discrepancies between gene expression and protein level. In addition, several differences observed in the pattern of MT gene expression between mollusc and mammalian species enable us to discuss and challenge a model for the induction of MT gene expression.

Genotoxic and stress inductive potential of cadmium in Xenopus laevis larvae

The present investigation evaluates the toxic potential of Cd in larvae of the frog Xenopus laevis after 12 days of exposure to environmentally relevant contamination levels, close to those measured in the river Lot (France). Several genotoxic and detoxification mechanisms were analyzed in the larvae: clastogenic and/or aneugenic effects in the circulating blood by micronucleus (MN) induction, metallothionein (MT) production in whole larvae, gene analyses and Cd content in the liver and also in the whole larvae. The results show: (i) micronucleus induction at environmental levels of Cd contamination (2, 10, 30 microgL(-1)); (ii) an increased and concentration-dependent quantity of MT in the whole organism after contamination with 10 and 30 microgCdL(-1) (a three- and six-fold increase, respectively) although no significant difference was observed after contamination with 2 microgCdL(-1); (iii) Cd uptake by the whole organism and by the liver as a response to Cd exposure conditions; (4) up-regulation of the genes involved in detoxification processes and response to oxidative stress, while genes involved in DNA repair and apoptosis were repressed. The results confirm the relevance of the amphibian model and highlight the complementarity between a marker of genotoxicity, MT production, bioaccumulation and genetic analysis in the evaluation of the ecotoxicological impact.

Characterization of free-floating spheres from human trabecular meshwork (HTM) cell culture in vitro

It has been observed in several tissues that direct isolation of cells in serum-free media and on nonadhesive substrates results in the formation of spherical clusters of cells known as free-floating spheres. Such free-floating spheres have been hypothesized to contain undifferentiated multipotent progenitor cells. Our goal was to isolate and characterize such free-floating spheres from HTM cell primary cultures. For this purpose, HTM cells were incubated in serum-free media and on a nonadhesive substrate. Individual free-floating spheres generated in these conditions were isolated in 96-well plates, and their proliferative capacity was evaluated by monitoring their size increase over time. The expression of the TM markers, MGP and CHI3L1, was examined using recombinant adenoviruses containing the respective promoters. Morphology of the free-floating spheres was analysed in semithin sections, and the gene expression profile was obtained using Human Genome U133 Plus 2.0 Affymetrix microarrays. HTM cells incubated in serum-free media and on nonadhesive substrate generated free-floating spheres that could be grown for more than 3 months. Addition of serum to the culture media promoted the attachment of the spheres to the substrate, migration of cells from the spheres, and differentiation into cells phenotypically similar to normal TM cells. Gene profiling analysis demonstrated strong similarities between the gene expression profiles of the spheres and HTM cell monolayers. Both infection with the recombinant adenoviruses and gene array analysis demonstrated the expression of CHI3L1 and MGP, indicating that free-floating spheres likely originate from HTM cells. Gene array analysis also showed expression of the marker for neural precursor cells nestin, as well as leukemia inhibitory factor, a gene involved in the maintenance of the undifferentiated state of progenitor cells. Analysis of semithin sections indicated that these TM free-floating spheres were highly dynamic structures demonstrating a distinct radial gradient of cell proliferation, survival, and apoptosis. Extensive up- and down-regulation of gene expression was associated with the processes of sphere attachment and cell migration after the addition of serum. These results suggest that HTM primary cultures might contain relatively undifferentiated or progenitor cells. The availability of TM progenitor cell cultures could constitute a useful tool to investigate cell therapy approaches targeting the TM in glaucoma.

Induction of TGF-beta1 in the trabecular meshwork under cyclic mechanical stress

The pathophysiological mechanisms involved in the failure of the trabecular meshwork (TM) to maintain normal levels of aqueous outflow in glaucoma are not yet understood. Aberrant activation of the transforming growth factor beta-1 (TGF-beta1) pathway has been implicated in several degenerative diseases. We investigated the possibility that chronic cyclic mechanical stress that affects the TM might result in increased production of TGF-beta1. Primary cultures of TM cells subjected to cyclic mechanical stress (5% stretching, 1 cycle/sec) demonstrate a significant increase in total and biologically active secreted TGF-beta1 that was associated with activation of the TGF-beta1 promoter, measured using a recombinant adenovirus expressing the secreted reporter gene secreted alkaline phosphatase protein (SEAP) under the TGF-beta1 gene promoter (AdTGFbeta1-SEAP). Associated changes in the transcription of MMP-2, TIMP-2, and CTGF were assessed by semiquantitative PCR. Immunohistochemical analysis of TGF-beta1 in organ culture of human eyes revealed a generalized accumulation of this protein in the extracellular matrix (ECM) of the TM, while expression of the TGF-beta1 promoter, analyzed using the LacZ reporter gene, was localized in some specific cells within the outflow pathway. Induction of the TGF-beta1 promoter in organ culture was demonstrated using a novel model for cyclic mechanical stress in human perfused anterior segments infected with AdTGFbeta1-SEAP. Given the relevant physiological and pathophysiological roles of TGF-beta1, its induction after cyclic mechanical stress in the TM supports the hypothesis that this cytokine might play a significant role in the physiology of the TM, and contribute to the pathological changes of this tissue in certain forms of glaucoma.

Comparative effects of dietary methylmercury on gene expression in liver, skeletal muscle, and brain of the zebrafish (Danio rerio)

Effects of dietary methylmercury (MeHg) on gene expression were examined in three organs (liver, skeletal muscle, and brain) of the zebrafish (Danio rerio). Adult male fish were fed over 7, 21, and 63 days on three different diets: one control diet (C0: 0.08 microg of Hg g(-1), dry wt) and two diets (C1 and C2) contaminated by MeHg at 5 and 13.5 microg of Hg g(-1), dry wt. Total Hg and MeHg concentrations were determined in the three organs after each exposure duration, and a demethylation process was evidenced only in the liver. Thirteen genes known to be involved in antioxidant defenses, metal chelation, active efflux of organic compounds, mitochondrial metabolism, DNA repair, and apoptosis were investigated by quantitative real-time RT-PCR and normalized according to actin gene expression. Surprisingly, no change in the expression levels of these genes was observed in contaminated brain samples, although this organ accumulated the highest mercury concentration (63.5 +/- 4.4 microg g(-1), dry wt after 63 days). This lack of genetic response could explain the high neurotoxicity of MeHg. coxI and cytoplasmic and mitochondrial sod gene expressions were induced early in skeletal muscle and later in liver, indicating an impact on the mitochondrial metabolism and production of reactive oxygen species. Results demonstrated that skeletal muscle was not only an important storage reservoir but was also affected by MeHg contamination. The expression of the metallothionein mt2 and the DNA repair rad51 genes was up-regulated in liver between 21 and 63 days, whereas in skeletal muscle, mt2 remained uninduced, and gadd and rad51 were found to be repressed.

Increased expression of two multidrug transporter-like genes is associated with ethidium bromide and ciprofloxacin resistance in Mycoplasma hominis

Two genes, md1 and md2, coding for multidrug resistance ATP-binding cassette transporters were identified in Mycoplasma hominis PG21. Expression of these two genes, quantified by quantitative competitive reverse transcription-PCR, was significantly increased in ethidium bromide-resistant strains of M. hominis compared to that in M. hominis PG21.

The effects of pupil size on the multifocal electroretinogram

This is an investigation of the effect of changing the pupil diameter on the P1 amplitude and latency of the multifocal electroretinogram (mfERG). MfERGs were recorded using a custom built wide field electrophysiological system. An array of 61 empirically scaled hexagons was used to stimulate the visual field. The duration of overall recording period was 8 min, segmented into 16 intervals each lasting 30 s. A combination of mydriatics and miotics were used to pharmacologically alter the pupil size and diameters between 1 and 10 mm were measured. There was a reduction in mfERG P1 amplitude in some cases greater than 50% (mfERG P1 amplitude 53 nV at 8 mm to 25 nV at 1 mm), with a change in pupil diameter of 7 mm. The mfERG P1 latency increased in some cases by as much as 8 ms in the central 40 degrees (mfERG P1 latency 39 ms at 8 mm to 47 ms at 1 mm). These results suggest that pupil size has significant effects on mfERG P1 amplitude and latency.