In vitro evaluation of the potential allelopathic and ichthyotoxic effect of the raphidophyte Heterosigma akashiwo and the dinoflagellate Alexandriumcatenella.

Ichthyotoxic algal blooms cause economic losses throughout the world. However, the mechanisms and molecules proposed so far fail to explain the massiveness of these events. In this research, the allelopathic effect of two bloom-forming species (the raphidophyte Heterosigma akashiwo and dinoflagellate Alexandrium catenella) was evaluated between them and with Rhodomonas salina bioassay. Mono- and co-cultures were carried out with the aim of providing evidence of the relation between allelopathy and ichthyotoxicity. The allelopathic inhibitory effect of the A. catenella's supernatant was significantly enhanced when supernatants were obtained from co-cultures with direct contact between these species. We could not observe any allelopathic response provoked by H. akashiwo. On the other hand, A. catenella was able to decrease the cell concentration of H. akashiwo and R. salina. Besides, allelopathy and ichthyotoxicity were found for A. catenella's supernant, being the allelopathic effect not related to saxitoxin. These results reinforce the hypothesis that the allelopathic effect being regulated by the presence of other microalgae and could be responsible for ichthyotoxicity.

SVCT2 Overexpression and Ascorbic Acid Uptake Increase Cortical Neuron Differentiation, Which Is Dependent on Vitamin C Recycling between Neurons and Astrocytes.

During brain development, sodium-vitamin C transporter (SVCT2) has been detected primarily in radial glial cells in situ, with low-to-absent expression in cerebral cortex neuroblasts. However, strong SVCT2 expression is observed during the first postnatal days, resulting in increased intracellular concentration of vitamin C. Hippocampal neurons isolated from SVCT2 knockout mice showed shorter neurites and low clustering of glutamate receptors. Other studies have shown that vitamin C-deprived guinea pigs have reduced spatial memory, suggesting that ascorbic acid (AA) and SVCT2 have important roles in postnatal neuronal differentiation and neurite formation. In this study, SVCT2 lentiviral overexpression induced branching and increased synaptic proteins expression in primary cultures of cortical neurons. Analysis in neuroblastoma 2a (Neuro2a) and human subventricular tumor C3 (HSVT-C3) cells showed similar branching results. SVCT2 was mainly observed in the cell membrane and endoplasmic reticulum; however, it was not detected in the mitochondria. Cellular branching in neuronal cells and in a previously standardized neurosphere assay is dependent on the recycling of vitamin C or reduction in dehydroascorbic acid (DHA, produced by neurons) by glial cells. The effect of WZB117, a selective glucose/DHA transporter 1 (GLUT1) inhibitor expressed in glial cells, was also studied. By inhibiting GLUT1 glial cells, a loss of branching is observed in vitro, which is reproduced in the cerebral cortex in situ. We concluded that vitamin C recycling between neurons and astrocyte-like cells is fundamental to maintain neuronal differentiation in vitro and in vivo. The recycling activity begins at the cerebral postnatal cortex when neurons increase SVCT2 expression and concomitantly, GLUT1 is expressed in glial cells.

Search for potential biomarkers for saxitoxin detection.

The Neuro-2a cell assay has been a promising in vitro alternative for the detection of saxitoxin (STX)-like toxins. However, its application is problematic in samples with complex matrices containing different toxins, whose mechanisms of action could be antagonistic. In the search of alternative procedures that reduce or avoid this interference, we evaluated the transcriptional modulation produced by a 24-h exposure to STX in Neuro-2a cells under three conditions: exposure to STX (33 nM), a mussel meat matrix (12.5 mg meat/mL) and a fortified sample (STX-fortified matrix). Differential gene expression was evaluated by RNA-seq after Illumina high-throughput sequencing, and data were analyzed to identify genes differentially expressed regardless of the matrix. From the 9487 identified genes, 213 were differentially expressed of these, 10 genes were identified as candidate markers for STX detection due to their regulation by STX regardless of the matrix interference. Expression dynamics of 7 of these candidate genes (Fgf-1, Adgrb2, Tfpt, Zfr2, Nup 35, Fam195a, and Dusp7) was further evaluated by qRT-PCR analysis of cells exposed to different concentrations of STX for up to 24 h. A downregulation of some markers expression was observed, namely Nup35 (involved in nucleo-cytoplasmic transporter activity) and Zfr-2 (involved in nucleic acids binding), whereas Fgf-1 (apoptosis signaling) was significantly upregulated. Markers' expression was not influenced by the matrix, suggesting that gene expression variations are directly related to STX response. These results support the potential of these genes as biomarkers for the development of an alternative STX-like toxins screening method.

Neuro-2a cell-based assay for toxicity equivalency factor - proposal and evaluation in Chilean contaminated shellfish samples.

There are two official PSP detection methods (mouse bioassay and HLPC-FLD) and a number of alternative methods. Ethical considerations have led to regulations being adopted in some countries that limit or prohibit the application of mouse bioassay. Analytical methodologies (e.g. HPLC-FLD or LC-MSMS) have the disadvantages of not being able to detect new toxins or analogues or reflecting the overall toxicity of the sample. In addition, they require highly trained personnel and expensive equipment, which are not always available. In this work, we have evaluated a method based on the Neuro-2a cell-based assay to detect substances that inhibit voltage-dependent sodium channels (Manger's method). We tested PSP standards and natural samples contaminated with PSP. Here we demonstrate that the adapted Manger's method is suitable for calculating Toxicity Equivalency Factors (TEF) for STX-analogues. The method was shown to be useful for screening contaminated natural samples in concentrations above the regulatory limit for these toxins (80 µg STX equivalents/100 g shellfish). We were able to detect PSP in 19 natural mollusc samples from South Chile despite the presence of other marine toxins. These preliminary results suggest that the method could be used as a first step in screening programmes.

Basal Sodium-Dependent Vitamin C Transporter 2 polarization in choroid plexus explant cells in normal or scorbutic conditions.

Vitamin C is incorporated into the cerebrospinal fluid (CSF) through choroid plexus cells. While the transfer of vitamin C from the blood to the brain has been studied functionally, the vitamin C transporter, SVCT2, has not been detected in the basolateral membrane of choroid plexus cells. Furthermore, it is unknown how its expression is induced in the developing brain and modulated in scurvy conditions. We concluded that SVCT2 is intensely expressed in the second half of embryonic brain development and postnatal stages. In postnatal and adult brain, SVCT2 is highly expressed in all choroidal plexus epithelial cells, shown by colocalization with GLUT1 in the basolateral membranes and without MCT1 colocalization, which is expressed in the apical membrane. We confirmed that choroid plexus explant cells (in vitro) form a sealed epithelial structure, which polarized basolaterally, endogenous or overexpressed SVCT2. These results are reproduced in vivo by injecting hSVCT2wt-EYFP lentivirus into the CSF. Overexpressed SVCT2 incorporates AA (intraperitoneally injected) from the blood to the CSF. Finally, we observed in Guinea pig brain under scorbutic condition, that normal distribution of SVCT2 in choroid plexus may be regulated by peripheral concentrations of vitamin C. Additionally, we observed that SVCT2 polarization also depends on the metabolic stage of the choroid plexus cells.

Study of the ichthyotoxic microalga Heterosigma akashiwo by transcriptional activation of sublethal marker Hsp70b in Transwell co-culture assays.

Despite the advance of knowledge about the factors and potential mechanisms triggering the ichthyotoxicity in microalgae, these remain unclear or are controversial for several species (e.g. Heterosigma). Neither typical toxicity tests carried out with cell extracts nor direct exposure to harmful species were proved suitable to unravel the mechanism of harm. Ichthyotoxic species show a complex harmful effect on fish, which is mediated through various mechanisms depending on the species. In this work, we present a method to study sub-lethal effects triggered by reactive oxygen species of a population of harmful algae in vivo over a fish cell line. To that end, Transwell co-cultures in which causative and target species are separated by a 0.4 µm pore membrane were carried out. This allowed the evaluation of the effect of the released molecules by cells in a rapid and compact test. In our method, the harmful effect was sensed through the transcriptional activation of sub-lethal marker Hsp70b in the CHSE214 salmon cell line. The method was tested with the raphidophyte Heterosigma akashiwo and Dunaliella tertiolecta (as negative control). It was shown that superoxide intracellular content and its release are not linked in these species. The methodology allowed proving that reactive oxygen species produced by H. akashiwo are able to induce the transcriptional activation of sub-lethal marker Hsp70b. However, neither loss of viability nor apoptosis was observed in CHSE214 salmon cell line except when exposed to direct contact with the raphidophyte cells (or their extract). Consequently, ROS was not concluded to be the main cause of ichthyotoxicity in H. akashiwo.

Calidad de vida en pacientes con neuropatía diabética periférica: estudio transversal en Lima, Perú / Quality of life among patients with peripheral diabetic neuropathy: a cross-sectional study in Lima, Peru

Objetivo: Evaluar la asociación entre la presencia de neuropatía periférica y calidad de vida en pacientes con diabetes mellitus tipo 2. Materiales y métodos: Estudio transversal que enroló pacientes con diabetes mellitus tipo 2, de 18 años a más en un hospital peruano de nivel terciario. La variable resultado fue calidad de vida, evaluada en las esferas física y mental usando el cuestionario 36-item Short Form (SF-36). El diagnóstico de neuropatía periférica fue dado por al menos una de las siguientes: prueba del monofilamento Semmes-Weinstein, prueba del diapasón 128 Hz, úlceras visibles en pie y/o artropatía de Charcot. La asociación de interés se verificó mediante regresión lineal. Resultados: Se incluyeron 330 pacientes, 56,6% mujeres, edad media: 61,3 (±11,5) años. La prevalencia de neuropatía periférica fue de 44,2% (IC95%: 38,8%-49,6%). De acuerdo a la esfera física del SF-36, la calidad de vida media fue de 46,8 (±6,3) puntos; mientras, la media de la calidad de vida en la esfera mental fue de 39,5 (±8,2) puntos. En modelo multivariable, la neuropatía periférica estuvo asociada a una reducción de dos puntos (β = -2,06; IC95%: -3,52; -0,60) en la calidad de vida en la esfera física, pero no afectó la calidad de vida en la esfera mental (β = 0,03; IC95%: -1,79; 1,85). Conclusiones: Existe asociación entre la presencia de neuropatía diabética periférica y calidad de vida en la esfera física, pero no en la esfera mental. Casi la mitad de los pacientes con diabetes presentaron neuropatía periférica.

Objective: To assess the association between the presence of peripheral neuropathy and life quality among patients with type 2 diabetes mellitus. Materials and methods: A cross-sectional study enrolling patients aged ≥18 years with diagnosis of type 2 diabetes mellitus in a tertiary-level hospital. The outcome was quality of life, assessed in the physical and mental spheres of the 36-item Short Form (SF-36). The diagnosis of peripheral neuropathy was given by the positivity of one of the following tests: Semmes-Weinstein monofilament test, 128 Hz tuning fork test, presence of visible foot ulcers and/or Charcot arthropathy. The linear regression model was used to verify the association of interest. Results: A total of 330 patients were enrolled, 56.6% female, mean age 61.3 years (±11.5). The prevalence of peripheral neuropathy was 44.2% (95%CI: 38.8%- 49.6%). Based on the physical sphere of the SF-36, the mean of the quality of life was 46.8 (±6.3) points; whereas, the mean of the quality of life in the mental sphere was 39.5 (±8.2). In multivariable model, peripheral neuropathy was associated with a reduction of 2 points (β = -2.06; IC95%: -3.52; -0.60) in the physical sphere of the quality of life score, but it did not change the mental sphere (β = 0.03; IC95%: -1.79; 1.85). Conclusions: The peripheral neuropathy among type 2 diabetes cases was associated with reduction of quality of life in the physical sphere, but not in the mental one. Almost half of diabetes patients had peripheral neuropathy.

microRNA-219 Reduces Viral Load and Pathologic Changes in Theiler's Virus-Induced Demyelinating Disease.

Analysis of microRNA (miR) expression in the central nervous system white matter of SJL mice infected with the BeAn strain of Theiler's murine encephalomyelitis virus (TMEV) revealed a significant reduction of miR-219, a critical regulator of myelin assembly and repair. Restoration of miR-219 expression by intranasal administration of a synthetic miR-219 mimic before disease onset ameliorates clinical disease, reduces neurogliosis, and partially recovers motor and sensorimotor function by negatively regulating proinflammatory cytokines and virus RNA replication. Moreover, RNA sequencing of host lesions showed that miR-219 significantly downregulated two genes essential for the biosynthetic cholesterol pathway, Cyp51 (lanosterol 14-α-demethylase) and Srebf1 (sterol regulatory element-binding protein-1), and reduced cholesterol biosynthesis in infected mice and rat CG-4 glial precursor cells in culture. The change in cholesterol biosynthesis had both anti-inflammatory and anti-viral effects. Because RNA viruses hijack endoplasmic reticulum double-layered membranes to provide a platform for RNA virus replication and are dependent on endogenous pools of cholesterol, miR-219 interference with cholesterol biosynthesis interfered virus RNA replication. These findings demonstrate that miR-219 inhibits TMEV-induced demyelinating disease through its anti-inflammatory and anti-viral properties.

Matrix effects on a cell-based assay used for the detection of paralytic shellfish toxins in bivalve shellfish samples.

Detecting marine biotoxins such as paralytic shellfish toxins (PSTs) is essential to ensuring the safety of seafood. The mouse bioassay is the internationally accepted method for monitoring PSTs, but technical and ethical issues have led to a search for new detection methods. The mouse neuroblastoma cell-based assay (Neuro-2a CBA) using ouabain and veratridine (O/V) has proven useful for the detection of PSTs. However, CBAs are sensitive to shellfish-associated matrix interferences. As the extraction method highly influences matrix interferences, this study compared three extraction protocols: Association of Official Analytical Chemists (AOAC) 2005.06, AOAC 2011.02 and an alternative liquid-liquid method. These methods were used to assess the matrix effect of extracts from four commercially important bivalve species (Chilean mussel, Magellan mussel, clam and Pacific oyster) in Neuro-2a CBA. Extracts from all three protocols caused a toxic effect in Neuro-2a cells (without O/V) when tested at a concentration of 25 mg of tissue-equivalent (TE) ml(-1). The greatest toxicity was obtained through the AOAC 2011.02 protocol, especially for the Chilean mussel and Pacific oyster extracts. Similar toxicity levels (less than 15%) were observed in all extracts at 3.1 mg TE ml(-1). When assessed in Neuro-2a CBA, AOAC 2005.06 extracts presented the lowest matrix interferences, while the highest interferences were observed for AOAC 2011.02 in Magellan mussel and clam extracts. Finally, the AOAC 2005.06 and alternative protocols were compared using Chilean mussel samples fortified with 40 and 80 µg STX per 100 g meat. The AOAC 2005.06 method demonstrated better results. In conclusion, the AOAC 2005.06 extracts exhibited the fewest interferences in the Neuro-2a CBA. Therefore, this extraction method should be considered for the implementation of Neuro-2a CBA as a high-throughput screening methodology for PST detection.

SVCT2 Overexpression in Neuroblastoma Cells Induces Cellular Branching that is Associated with ERK Signaling.

Expression of the sodium and ascorbic acid (AA) cotransporter SVCT2 is induced during the period of cellular arborization and synaptic maturation of early postnatal (P1-P5) rat cerebral neurons. The physiological importance of the transporter for neurons is evidenced by the lethality and delayed neuronal differentiation detected in mice with ablation of SVCT2. The mechanism(s) involved in these defects and the role of SVCT2 in neuronal branching have not been determined yet. To address this, we used lentiviral expression vectors to increase the levels of SVCT2 in N2a cells and analyzed the effects on neurite formation. Expression of a fusion protein containing the human SVCT2wt and EYFP induced an increase in the number of MAP2+ neurites and filopodia in N2a cells. Overexpression of SVCT2 and treatment with AA promoted ERK1/2 phosphorylation. Our data suggest that enhanced expression of the high affinity AA transporter SVCT2, which tightly regulates intracellular AA concentrations, induces neuronal branching that then activates key signaling pathways that are involved in the differentiation and maturation of cortical neurons during postnatal development.

Saxitoxin Modulates Immunological Parameters and Gene Transcription in Mytilus chilensis Hemocytes.

Saxitoxin (STX) is a neurotoxin produced by dinoflagellates in diverse species, such as Alexandrium spp., and it causes paralytic shellfish poisoning (PSP) in humans after the ingestion of contaminated shellfish. Recent studies have suggested that the immune functions of bivalves could be affected by harmful algae and/or by their toxins. Herein, hemocytes are the main effector cells of the immune cellular response. In this study, we evaluated the response of hemocytes from the mussel Mytilus chilensis to STX exposure in a primary culture. Cell cultures were characterized according to size and complexity, while reactive oxygen species (ROS) production was evaluated using a dichlorofluorescein diacetate (DCFH-DA) assay. Finally, phagocytic activity was measured using both flow cytometry and fluorescence microscopy assays. Additionally, gene transcription of candidate genes was evaluated by qPCR assays. The results evidenced that exposures to different concentrations of STX (1-100 nM) for 24 h did not affect cell viability, as determined by an MTT assay. However, when hemocytes were exposed for 4 or 16 h to STX (1-100 nM), there was a modulation of phagocytic activity and ROS production. Moreover, hemocytes exposed to 100 nM of STX for 4 or 16 h showed a significant increase in transcript levels of genes encoding for antioxidant enzymes (SOD, CAT), mitochondrial enzymes (COI, COIII, CYTB, ATP6, ND1) and ion channels (K+, Ca2+). Meanwhile, C-type lectin and toll-like receptor genes revealed a bi-phase transcriptional response after 16 and 24-48 h of exposure to STX. These results suggest that STX can negatively affect the immunocompetence of M. chilensis hemocytes, which were capable of responding to STX exposure in vitro by increasing the mRNA levels of antioxidant enzymes.

Human choroid plexus papilloma cells efficiently transport glucose and vitamin C.

In vitro and in vivo studies suggest that the basolateral membrane of choroid plexus cells, which is in contact with blood vessels, is involved in the uptake of the reduced form of vitamin C, ascorbic acid (AA), through the sodium-vitamin C cotransporter, (SVCT2). Moreover, very low levels of vitamin C were observed in the brains of SVCT2-null mice. The oxidized form of vitamin C, dehydroascorbic acid (DHA), is incorporated through the facilitative glucose transporters (GLUTs). In this study, the contribution of SVCT2 and GLUT1 to vitamin C uptake in human choroid plexus papilloma (HCPP) cells in culture was examined. Both the functional activity and the kinetic parameters of GLUT1 and SVCT2 in cells isolated from HCPP were observed. Finally, DHA uptake by GLUT1 in choroid plexus cells was assessed in the presence of phorbol-12-myristate-13-acetate (PMA)-activated human neutrophils. A marked increase in vitamin C uptake by choroid plexus cells was observed that was associated with superoxide generation and vitamin C oxidation (bystander effect). Thus, vitamin C can be incorporated by epithelial choroid plexus papilloma cells using the basolateral polarization of SVCT2 and GLUT1. This mechanism may be amplified with neutrophil infiltration (inflammation) of choroid plexus tumors. In choroid plexus papilloma cells, the vitamin C transporters SVCT2 and GLUT1 are polarized to the basolateral epithelial membrane, where SVCT2 is essential for AA flux from the blood vessels into the brain. However, neutrophils, attracted by inflammation or the tumor microenvironment, can oxidize extracellular AA to DHA, thereby enabling its uptake through GLUT1. For the first time, we show the in vivo and in vitro basolateral co-distribution of functional SVCT2 and GLUT1 in epithelial cells. We postulate that patients with choroid plexus papillomas may continue to transport vitamin C from the blood to CSF. However, increased transport of oxidized vitamin C could generate pro-oxidative conditions that may help control tumor growth.

Clinical and experimental approaches to knee cartilage lesion repair and mesenchymal stem cell chondrocyte differentiation.

Cartilage has poor regeneration capacity due to the scarcity of endogenous stem cells, its low metabolic activity and the avascular environment. Repair strategies vary widely, including microfracture, autologous or allogenic tissue implantation, and in vitro engineered tissues of autologous origin. However, unlike the advances that have been made over more than two decades with more complex organs, including vascular, cardiac or bone tissues, similar advances in tissue engineering for cartilage repair are lacking. Although the inherent characteristics of cartilage tissue, such as the lack of vascularity and low cellular diversity, suggest that it would be one of the more simple tissues to be engineered, its functional weight-bearing role and implant viability and adaptation make this type of repair more complex. Over the last decade several therapeutic approaches and innovative techniques show promise for lasting and functional regeneration of hyaline cartilage. Here we will analyze the main strategies for cartilage regeneration and discuss our experience.

Clinical and experimental approaches to knee cartilage lesion repair and mesenchymal stem cell chondrocyte differentiation

Cartilage has poor regeneration capacity due to the scarcity of endogenous stem cells, its low metabolic activity and the avascular environment. Repair strategies vary widely, including microfracture, autologous or allogenic tissue implantation, and in vitro engineered tissues of autologous origin. However, unlike the advances that have been made over more than two decades with more complex organs, including vascular, cardiac or bone tissues, similar advances in tissue engineering for cartilage repair are lacking. Although the inherent characteristics of cartilage tissue, such as the lack of vascularity and low cellular diversity, suggest that it would be one of the more simple tissues to be engineered, its functional weight-bearing role and implant viability and adaptation make this type of repair more complex. Over the last decade several therapeutic approaches and innovative techniques show promise for lasting and functional regeneration of hyaline cartilage. Here we will analyze the main strategies for cartilage regeneration and discuss our experience.

[Diabetes as a risk factor for infections in cirrhotic patients]. / Diabetes como Factor de Riesgo para Infecciones en Pacientes Cirróticos.

AIMS AND OBJECTIVES: Infections are a common cause of morbidity and mortality in cirrhotic patients. Diabetes Mellitus (DM) is a predisposing factor for infections, and coexistence of DM and cirrhosis has increased in the last years, particularly in cirrhosis caused by hepatitis C virus. The aim of this study was to determine if there is an association between DM and infections in patients with cirrhosis. METHODS: Retrospective, cross sectional, analytical, multicenter study. Patients included were distributed in two groups: those with DM (glucose > 126 mg/dl) and those without DM. Frequency and type of infections were compared between both groups. Data was analyzed using Student's t test, Chi square, and Odds ratio analysis. RESULTS: 178 patients were included, 60.1% were male. Range age was between 25 and 88 years, and 25.8% reported DM. There were no demographic differences between groups. The frequency of infections in the DM group was 84.8% as compared to 48.5% in the controls (p=0.001; OR = 5.9). The most common infections were Urinary Tract Infection (UTI), Pneumonia, and Cellulites. We found a higher frequency of Pneumonia in the DM group, not so for UTI and Cellulites population. CONCLUSIONS: The occurrence of DM is a risk factor for infections in patients with hepatic cirrhosis, particularly increased is the risk for acquiring Pneumonia. KEYWORDS: Cirrhosis, Diabetes mellitus, Infections.

Diabetes como factor de riesgo para infecciones en pacientes cirróticos / Diabetes as a risk factor for infections in cirrhotic patients

INTRODUCCIÓN: Las infecciones son causa común de morbi-mortalidad en pacientes cirróticos. La Diabetes Mellitus (DM) es un reconocido factor predisponente a infecciones y cuya coexistencia como causa o consecuencia se ha visto incrementada en la poblacióncirrótica, de manera particular en población cirrótica de etiología viral de tipo C y cuya prevalencia ha sido reportada hasta en más del 50 por ciento de pacientes en algunas series. Partimos de la hipótesis que la DM constituye un factor de riesgo para infecciones en los pacientes con Cirrosis Hepática. Nos planteamos el siguiente objetivo general: Determinar si existe asociación entre DM e infecciones en pacientes con cirrosis hepática. MATERIAL Y MÉTODOS: Estudio transversal, analítico, multicéntrico. Se dividió en 2 grupos, aquellos con DM (glicemia > 126 mg/dl) y sin DM. Se realizó una comparación de frecuencia y el tipo de infecciones en cada grupo. El análisis se realizó mediante las pruebas t Student, Chi Cuadrado y Odds Ratio como medida de asociación. RESULTADOS: Se incluyeron 178 pacientes (60,1 por ciento varones) entre 25 y 88 años. El 25,8 por cientotuvieron DM. No hubo diferencias demográficas entre los grupos DM y NDM. La frecuencia de infecciones en DM fue de 84,8 por ciento comparada con 48,5 por ciento en los no DM (p = 0,001 y OR = 5,90). Las infecciones más comunes fueron infecciones urinarias (ITU), neumonías y celulitis. Encontramos una mayor frecuencia de neumonías en el grupo DM, no así de ITU ni celulitis. CONCLUSIÓN: Existe una mayor frecuencia de infecciones en los pacientes cirróticos con DM. La frecuencia de Neumonías es mayor entre cirróticos infectados con DM, no así la de ITU o de celulitis.

AIMS AND OBJECTIVES: Infections are a common cause of morbidity and mortality in cirrhotic patients. Diabetes Mellitus (DM) is a predisposing factor for infections, and coexistence of DM and cirrhosis has increased in the last years, particularly in cirrhosis caused by hepatitis C virus. The aim of this study was to determine if there is an association between DM and infections in patients with cirrhosis. METHODS: Retrospective, cross sectional, analytical, multicenter study. Patients included were distributed in two groups: those with DM (glucose > 126 mg/dl) and those without DM. Frequency and type of infections were compared between both groups. Data was analyzed using Student´s t test, Chi square, and Odds ratio analysis. RESULTS: 178 patients were included, 60.1 percent were male. Range age was between 25 and 88 years, and 25.8 percent reported DM. There were no demographic differences betweengroups. The frequency of infections in the DM group was 84.8 percent as compared to 48.5 percent in the controls (p=0.001; OR = 5.9). The most common infections were Urinary Tract Infection (UTI), Pneumonia, and Cellulites. We found a higher frequency of Pneumonia in the DM group, not so for UTI and Cellulites population. CONCLUSIONS: The occurrence of DM is a risk factor for infections in patients with hepatic cirrhosis, particularly increased is the risk for acquiring Pneumonia.

[Demographic Dynamics and Educational Inequality in Mexico]. / La dinámica demográfica y la desigualdad educativa en México.

This paper seeks to explore the link between educational processes and Mexico's demographic dynamic. In the tradition of thought on population and development, it has been hypothesized that the population growth rate, family size and migration influence the accumulation of human capital among the school-age population. This study explores the link between the academic performance of youth between the age of 14 and 23 and the youth dependency ratio, teenage fertility and internal and international migration, using data aggregated at the municipal level for the year 2000. The analysis uses indicators on the educational supply at the municipal level based on the administrative statistics of the Public Education Secretariat (SEP).

Differential subcellular distribution of glucose transporters GLUT1-6 and GLUT9 in human cancer: ultrastructural localization of GLUT1 and GLUT5 in breast tumor tissues.

It has been proposed that the enhanced metabolic activity of tumor cells is accompanied by an increased expression of facilitative hexose transporters (GLUTs). However, a previous immunohistochemical analysis of GLUT1 expression in 154 malignant human neoplasms failed to detect the GLUT1 isoform in 87 tumors. We used 146 normal human tissues and 215 tumor samples to reassess GLUT1 expression. A similar number of samples were used to compare the expression of GLUT2-6 and 9. The classical expression of GLUT1-5 in different normal human tissues was confirmed, however, we were unable to detect GLUT2 in human pancreatic islet cells. GLUT6 was principally detected in testis germinal cells and GLUT9 was localized in kidney, liver, heart, and adrenal. In tumor samples, GLUT1, 2, and 5 were the main transporters detected. GLUT1 was the most widely expressed transporter, however, 42% of the samples had very low-to-negative expression levels. GLUT2 was detected in 31% of the samples, being mainly expressed in breast, colon, and liver carcinoma. GLUT5 was detected in 27% of breast and colon adenocarcinoma, liver carcinoma, lymphomas, and testis seminoma samples. In situ RT-PCR and ultrastructural immunohistochemistry confirmed GLUT5 expression in breast cancer. GLUT6 and 9 are not clearly over-expressed in human cancer. The extensive expression of GLUT2 and 5 (glucose/fructose and fructose transporters, respectively) in malignant human tissues indicates that fructose may be a good energy substrate in tumor cells. Our functional data obtained in vitro in different tumor cells support this hypothesis. Additionally, these results suggest that fructose uptake could be used for positron emission tomography imaging and, may possibly represent a novel target for the development of therapeutic agents in different human cancers.

Vitamin C uptake and recycling among normal and tumor cells from the central nervous system.

Specialized cells transport vitamin C in its reduced form using sodium-dependent cotransporters (SVCT1 and SVCT2). Additionally, different cells transport the oxidized form of vitamin C, dehydroascorbic acid, through glucose transporters (GLUTs). We have proposed recently a model for vitamin C uptake that resolves the apparent contradiction that although only ascorbic acid is detectable in vivo, there are cells that transport only dehydroascorbic acid. We carried out a detailed kinetic analysis to compare the mechanisms of vitamin C uptake in normal human melanocytes, neurons isolated from brain cortex, hypothalamic ependymal-glial cells, and astrocytes. Uptake of ascorbic acid was also analyzed in the human oligodendroglioma cell line TC620, in human choroid plexus papilloma cells (HCPPC-1), and in the neuroblastoma cell line Neuro-2a. Melanocytes were used to carry out a detailed analysis of vitamin C uptake. Analysis of the transport data by the Lineweaver-Burk plot revealed the presence of one functional component (K(m) 20 microM) involved in ascorbic acid transport by melanocytes. Vitamin C sodium-dependent saturable uptake was also observed in neurons and hypothalamic tanycytes. We confirmed SVCT2 expression in neurons by in situ hybridization; however, SVCT2 expression was not detected in astrocytes in situ. Functional data indicate that astrocytes transport mainly dehydroascorbic acid, using the glucose transporter GLUT1. Our functional uptake analyses support the hypothesis that astrocytes are involved in vitamin C recycling in the nervous system. This recycling model may work as an efficient system for the salvage of vitamin C by avoiding the hydrolysis of dehydroascorbic acid produced by antioxidative protection.