Chromosomally Unstable Gastric Cancers Overexpressing Claudin-6 Disclose Cross-Talk between HNF1A and HNF4A, and Upregulated Cholesterol Metabolism.

(1) Abnormally increased expression of claudin-6 in gastric cancer is considered a prognostic marker of the chromosomal unstable molecular subtype. However, a detailed molecular profile analysis of differentially expressed genes and affected pathways associated with claudin-6 increased (Cldn6high) expression has not been assessed. (2) The TCGA Stomach Adenocarcinoma Pan-Cancer Atlas Data was evaluated using Cytoscape's Gene Mania, MCODE, and Cytohubba bioinformatic software. (3) 96.88% of Cldn6high gastric cancer tumors belonging to the chromosomal unstable molecular subtype are associated with a worse prognosis. Cldn6expression coincided with higher mutations in TP53, MIEN1, STARD3, PGAP3, and CCNE1 genes compared to Cldn6low expression. In Cldn6high cancers, 1316 genes were highly expressed. Cholesterol metabolism was the most affected pathway as APOA1, APOA2, APOH, APOC2, APOC3, APOB-100, LDL receptor-related protein 1/2, Sterol O-acyltransferase, STARD3, MAGEA-2, -3, -4, -6, -9B, and -12 genes were overexpressed in Cldn6high gastric cancers; interestingly, APOA2 and MAGEA9b were identified as top hub genes. Functional enrichment of DEGs linked HNF-4α and HNF-1α genes as highly expressed in Cldn6high gastric cancer. (4) Our results suggest that APOA2 and MAGEA9b could be considered as prognostic markers for Cldn6high gastric cancers.

Claudin-6 increases SNAI1, NANOG and SOX2 gene expression in human gastric adenocarcinoma AGS cells.

BACKGROUND: Gastric cancer is a heterogeneous disease associated to deregulated gastric epithelia tight junction barrier function and di novo expression of claudin-6; these changes are associated with epithelial-mesenchymal transition, enhanced invasiveness, metastatic progression, resistance to chemotherapy, and poor prognosis. Gastric cancer stem cells represent a rare population of cells within the tumor implicated in tumor growth and higher tumorigenic capacity. The possible relation between claudin-6 expression and the expression of some markers associated to epithelial mesenchymal transition and cancer stem cells in gastric cancer cells have never been explored. METHODS AND RESULTS: CD44, CD24, Twist, Villin, DCLK1, claudin-6, NANOG, E-Cadherin, SOX2, and SNAI1 expression was evaluated by immunofluorescence and cytofluorometry in wild type and Claudin-6 transfected AGS cells. Cell migration assays were also performed. Differentially expressed genes and biological processes analysis was performed to determine gene preponderance. The results showed that claudin-6 overexpression enriched the CD44 + /CD24- subpopulation with an overall increase in the expression and the number of CD44 + cells. A significant increase in NANOG, SOX2 and SNAI1 expression and enhanced cell migration was observed in claudin-6 transfected cells. Transcriptome analysis revealed 271 genes involved in enhanced biological processes with only 31 with a significantly p value; thirteen of those genes are closely associated to epithelial mesenchymal transition processes and folding and unfolding processes of proteins in the endoplasmic reticulum. CONCLUSIONS: The pro-tumorigenic effect of claudin-6 in gastric cancer could be associated to dedifferentiation of epithelial cells and an increase in di novo cancer stem cell genesis.

Proteolytic Processing of CD44 and Its Implications in Cancer.

CD44 is a transmembrane glycoprotein expressed in several healthy and tumor tissues. Modifications in its structure contribute differently to the activity of this molecule. One modification that has provoked interest is the consecutive cleavage of the CD44 extracellular ectodomain by enzymes that belong mainly to the family of metalloproteases. This process releases biologically active substrates, via alternative splice forms of CD44, that generate CD44v3 or v6 isoforms which participate in the transcriptional regulation of genes and proteins associated to signaling pathways involved in the development of cancer. These include the protooncogene tyrosine-protein kinase Src (c-Src)/signal transducer and activator of transcription 3 (STAT3), the epithelial growth factor receptor, the estrogen receptor, Wnt/ßcatenin, or Hippo signaling pathways all of which are associated to cell proliferation, differentiation, or cancer progression. Whereas CD44 still remains as a very useful prognostic cell marker in different pathologies, the main topic is that the generation of CD44 intracellular fragments assists the regulation of transcriptional proteins involved in the cell cycle, cell metabolism, and most importantly, the regulation of some stem cell-associated markers.

Vanadium pentoxide induces activation and death of endothelial cells.

Vanadium is a transition metal released into the atmosphere, as air-suspended particles, as a result of the combustion of fossil fuels and some metallurgic industry activities. Air-suspended particle pollution causes inflammation-related processes such as thrombosis and other cardiovascular events. Our aim was to evaluate the effect of vanadium pentoxide (V2O5) on endothelial cells since they are key participants in the pathogenesis of several cardiovascular and inflammatory diseases. Cell adhesion, the expression of adhesion molecules and oxidative stress, as well as proliferation, morphology and cell death of human umbilical vein endothelial cells (HUVECs) exposed to V2O5, were evaluated. Vanadium pentoxide at a 3.12 µg cm(-2) concentration induced an enhanced adhesion of the U937 macrophage cell line to HUVECs, owing to an increased expression of late adhesion molecules. HUVECs exposed to V2O5 showed an increase in ROS and nitric oxide production, and a diminished proliferation. These changes in vanadium-treated HUVECs were accompanied by severe morphological changes and apoptotic cell death. Vanadium pentoxide induced serious endothelial cell damage, probably related to the increased cardiovascular morbidity and mortality observed in individuals living in highly air-polluted areas.

Claudin-6, 7, or 9 overexpression in the human gastric adenocarcinoma cell line AGS increases its invasiveness, migration, and proliferation rate.

Altered claudin expression is related to metastatic potential, poor prognosis, or tumor recurrence. We analyzed if the overexpression of claudin-6, claudin-7, or claudin-9 in AGS cells altered cell motility, invasiveness, or proliferation rate. Claudin-7, claudin-9, and claudin-6 enhanced their invasive potential by 3.4-fold, 1.6-fold, and 2.0-fold, respectively. Claudin-6 and claudin-9 enhanced cell migration, while the proliferation rate of claudin-6-, claudin-7-, and claudin-9-transfected cells increased by 12.7%, 9.0%, and 13.3%, respectively. Claudin-7 and claudin-9 overexpression increased claudin-1 and zonula occludens-1 levels. In summary, individual increased expression of claudin-6, claudin-7, or claudin-9 is sufficient to enhance tumorigenic properties of a gastric adenocarcinoma cell line.

Distribution and expression pattern of claudins 6, 7, and 9 in diffuse- and intestinal-type gastric adenocarcinomas.

INTRODUCTION: Intestinal- and diffuse-type gastric adenocarcinomas differ in clinical outcome and genetic profile. Abnormal claudin expression has been well documented in several malignancies. Our aim was to find specific claudin markers for each type. METHODS: Fifty paraffin-embedded tissue blocks of diffuse- and intestinal-type gastric adenocarcinomas and fresh gastric biopsies obtained endoscopically from 20 patients with a presumptive diagnosis of gastric cancer were analyzed. Claudin-specific polyclonal and monoclonal antibodies were used for immunohistochemistry and Western blot analysis in total lysate and subcellular fractions. RESULTS: Claudin-6 expression was high in both types. Claudin-7 was expressed mainly in the diffuse-type whereas claudin-9 was mainly found in the apical membrane of the gland cells in the intestinal-type. Strong claudin-9 expression was associated with higher mortality rate (66%) in the diffuse type vs the intestinal type (25%) after a 2-year follow-up. CONCLUSION: Claudins 6, 7, and 9 expressions are closely related to gastric carcinogenesis, and their detection is a useful prognostic marker in "intestinal-" and "diffuse-type" gastric adenocarcinomas.

The antithrombotic effect of the aminoestrogen prolame (N-(3-hydroxy-1,3,5(10)-estratrien-17B-YL)-3-hydroxypropylamine) is linked to an increase in nitric oxide production by platelets and endothelial cells.

OBJECTIVE: Women under hormone replacement therapy carry an increased risk of venous thromboembolism (VTE), mostly during the first year. Despite great efforts devoted to hormone therapy research, VTE remains a major drawback of estrogenic therapy, and the search for new compounds continues. We have synthesized and evaluated prolame, an aminoestrogen with anticoagulant properties. The aim of our work was to elucidate the anticoagulant mechanism of prolame. METHODS: We studied the effects of prolame on nitric oxide (NO) synthesis in cultured endothelial cells and platelets using flow cytometry, on NO metabolites using a modified Griess method, on NO formation in vivo using electron paramagnetic resonance spectroscopy, on participation of nuclear estrogen receptors using flow cytometry, and on endothelial NO synthase (eNOS) mRNA expression using RT-PCR. We also studied the impact of prolame-treated endothelial cells (EC) on ADP-induced platelet aggregation, as well as the ability to prevent occlusive thrombi in an in vivo mice thrombosis model. RESULTS: (a) Prolame induces NO production in ECs, platelets, and in a mouse model in vivo. (b) The NO-elevating effect of prolame can only be partially attributed to the nuclear estrogen receptors (ERs) since endothelial nitric oxide synthase (e-NOS) is slightly induced (37%) in ECs treated with prolame. (c) Platelets become 60% less responsive to aggregation induced by 10muM ADP when in suspension with prolame-treated ECs. (d) Prolame reduces the formation of thrombi in an in vivo thrombosis model. CONCLUSIONS: Prolame could be a preferred alternative to other estrogens because of its reduced thromboembolic risk.

Hypertriglyceridemia is linked to reduced nitric oxide synthesis in women with hypertensive disorders of pregnancy.

BACKGROUND: Hypertensive disorders of pregnancy (HDP), which affect 8% to 15% of pregnancies, are associated with nitric oxide dysfunction and hyperlipidemia, but their precise role in HDP remains controversial. In order to gain more insight into the mechanisms underlying HDP, we evaluated some indicators common to the diseases associated with endothelial dysfunction. METHODS: Plasma samples were obtained from 47 normotensive women (control group) and from 27 women with HDP (experimental group). All women were 7 months pregnant. Body mass index as well as triglycerides, nitrite concentrations, total cholesterol, LDL-cholesterol, HDL-cholesterol, glucose, and glycated hemoglobin were determined. RESULTS: Our results showed significant differences in body mass index (30.4 +/- 1.3 vs 28.3 +/- 0.6 kg/m(2), p < 0.05), triglycerides (363 +/- 137 vs. 263 +/- 80 mg/dL, p < 0.01), nitrites (19.6 +/- 5.2 vs. 15.2 +/- 5.0 micromol/L, p < 0.01), and glucose (92 +/- 25 vs. 81 +/- 10.8 mg/dL, p < 0.05) in women from the experimental group compared with the control group. Interestingly, nitric oxide synthesis was significantly reduced when triglycerides and cholesterol concentrations were increased (p < 0.018 and p < 0.002, respectively). Moreover, there was a strong association (odds ratio, 3.5) between a family history of type 2 diabetes mellitus and the development of HDP, especially preeclampsia. CONCLUSIONS: It may be useful to screen pregnant women for plasma nitrites and serum triglycerides to identify those at risk of developing HDP, especially in women with a family history of type 2 diabetes mellitus.

Dehydroepiandrosterone inhibits the TNF-alpha-induced inflammatory response in human umbilical vein endothelial cells.

Dehydroepiandrosterone (DHEA) has a protective role against atherosclerosis. We determined the effect of pharmacological doses of DHEA upon the adhesion of monocytic U937 cells to human umbilical vein endothelial cells (HUVEC), as well as the expression of adhesion and chemoattractant molecules, the translocation of NF-kappaB, the degradation of IkappaB-alpha and the production of reactive oxygen species (ROS) in HUVEC. Adhesion of U937 cells to DHEA-treated HUVEC was evaluated by co-culture experiments using [(3)H]-thymidine-labeled U937 cells. The expression of adhesion and chemoattractant molecules was evaluated by flow cytometry and RT-PCR, respectively; NF-kappaB translocation was determined by Electrophoretic Mobility Shift Assay (EMSA) and IkappaB-alpha degradation by Western blot. ROS production was determined by the reduction of fluorescent DCFDA. TNF-alpha was used to induce inflammatory responses in HUVEC. One hundred micromolar of DHEA-treatment inhibited the TNF-alpha-induced expression of ICAM-1, E-selectin, ROS production and U937 cells adhesion to HUVEC, and interfered with NF-kappaB translocation and IkappaB-alpha degradation. DHEA at the above mention concentration also inhibited the mRNA expression of MCP-1 and IL-8 in basal conditions but not in TNF-alpha-stimulated conditions. Our results suggest that DHEA inhibits the expression of molecules involved in the inflammatory process, therefore it could be used as an alternative in the treatment of chronic inflammatory diseases such as atherosclerosis.

Oral glycine administration attenuates diabetic complications in streptozotocin-induced diabetic rats.

Diabetes mellitus is a disease characterized by impaired glucose metabolism that leads to retinopathy, brain micro-infarcts and other complications. We have previously shown that oral glycine administration to diabetic rats inhibits non-enzymatic glycation of hemoglobin and diminishes renal damage. In this work, we evaluated the capacity of the amino acid glycine (1% w/v, 130 mM) to attenuate diabetic complications in streptozotocin (STZ)-induced diabetic Wistar rats and compared them with non-treated or taurine-treated (0.5% w/v, 40 mM) diabetic rats. Glycine-treated diabetic rats showed an important diminution in the percentage of animals with opacity in lens and microaneurysms in the eyes. Interestingly, there was a diminished expression of O-acetyl sialic acid in brain vessels compared with untreated diabetic rats (P<0.05). Additionally, peripheral blood mononuclear cells isolated from glycine-treated diabetic rats showed a better proliferative response to PHA or ConA than those obtained from non-treated diabetic rats (P<0.05). Glycine-treated rats had a less intense corporal weight loss in comparison with non-treated animals. Our results suggest that administration of glycine attenuates the diabetic complications in the STZ-induced diabetic rat model, probably due to inhibition of the non-enzymatic glycation process.

Direct cardiac injection of G-CSF mobilized bone-marrow stem-cells improves ventricular function in old myocardial infarction.

Autologous transplant of bone marrow stem cells (BMSC), although extremely useful after acute myocardial events, has not been evaluated in patients with old (>one-year-old) myocardial infarction. Our aim was to determine if CD34(+)-enriched peripheral-blood cells, obtained by apheresis, injected directly into the severely damaged myocardium of five patients with old myocardial infarction could restore depressed myocardial function. We found that 28 weeks after revascularization and peri-infarction injection of the enriched CD34(+) peripheral mononuclear cells, ventricular hemodynamic parameters that included left ventricular ejection fraction, left ventricular diastolic volume, ventricular systolic volume and left ventricular diastolic diameter approximated normal values and there was no restenosis; two patients have been followed for >52 weeks and their parameters are within normal values. In conclusion, intramyocardial injection of easily obtained CD34(+) enriched peripheral blood cells represent an encouraging procedure for patients with severely scarred and dysfunctional myocardium.

Perspectivas de las células tallo en infartos del miocardio / Stem cell perspectives in myocardial infarctions

Myocardial infarction is the leading cause of congestive heart failure and death in industrializated countries. The cellular cardiomyoplasty has emerged as an alternative treatment in the regeneration of infarted myocardial tissue. In animals' models, differents cellular lines such as cardiomyocites, sheletal myoblast, embryonic stem cells and adult mesenchymal stem cells has been used, resulting in an improvement in ventricular function and decrease in amount of infarted tissue. The first three cells line have disvantages as they are allogenics and are difficult to obtain. The adult mesenchymal stem cells are autologous and can be obtained throught the aspiration of bone marrow or from peripherical circulation, prior to stimulating with cytokines (G-CSF). The implantation in humans with recent and old myocardial infarction have shown improvements similar to those shown in animal models. These findings encourage the continued investigation in the mechanism of cellular differentiation and implantation metods in infarted myocardial tissue.

El infarto del miocardio es la principal causa de falla cardiaca y muerte en países industrializados. A la fecha, la cardiomioplastia celular ha emergido como una alternativa en la regeneración de infartos miocárdicos. En modelos animales se han utilizado diferentes líneas celulares como cardiomiocitos fetales, mioblastos de músculo esquelético, células tallo embrionarias y células tallo mesenquimales del adulto, con mejoría en la función ventricular y disminución del área de tejido infartado. Las tres primeras líneas celulares tienen desventajas porque son alogénicas y difíciles de obtener. Las células tallo mesenquimales del adulto son autólogas y se pueden obtener de aspirados de médula ósea o de la circulación periférica previa estimulación con citocinas (G-CSF). La implantación de estas células en seres humanos con infartos del miocardio recientes y antiguos han mostrado mejorías similares a los reportes con modelos animales. Estos hallazgos alientan a continuar la investigación clínica y básica en busca de los mecanismos de diferenciación celular y selección de vías de implantación, en tejido miocárdico infartado.

Inmunogenicidad y tolerancia de una vacuna contra influenza, en una población mexicana mayor de 55 años de edad / Immunogenicity and safety of the influenza vaccine, in a population older than 55-years in Mexico

OBJETIVO: Verificar la inmunogenicidad y tolerancia de una vacuna purificada, inactivada y fraccionada contra influenza, en adultos mexicanos derechohabientes de Petróleos Mexicanos (Pemex). MATERIAL Y MÉTODOS: Se incluyeron 90 adultos mayores de 55 años de edad, derechohabientes de los servicios médicos del Hospital Central Sur Pemex, durante los meses de noviembre y diciembre de 2000. Los criterios evaluados en relación con la inmunogenicidad incluyeron el porcentaje de sujetos protegidos, cuantificados por medio de anticuerpos antihemaglutininas superior o igual a 1:40, así como por el porcentaje de seroconversión determinado por el título inicial de anticuerpos multiplicado por un factor 4X. Los criterios secundarios fueron la frecuencia de reacciones adversas tanto locales como sistémicas. Se realizaron estudios de afinidad antígeno-anticuerpo para determinar la respuesta policlonal de anticuerpos y de anticuerpos de alta afinidad prevacunación y posvacunación. Se calcularon frecuencias y porcentajes. RESULTADOS: Se identificó una seroprotección en 95.6 por ciento de los sujetos a la cepa H1N1, de 98.9 por ciento a la cepa H3N2 y de 100 por ciento a la cepa B/ Yamanashi. En cuanto a los porcentajes de seroconversión, se identificó un incremento 4X de 74.4 para la cepa H1N1, de 88.9 para la cepa H3N2, y de 82.2 para la cepa B / Yamanashi. Un total de 18 individuos (20 por ciento) presentaron reacciones locales, mientras que 17 (18.8 por ciento) presentaron reacciones sistémicas a los cinco días posvacunación y nueve sujetos (10 por ciento) a los 28 días. Las reacciones locales a los cinco días consistieron en dolor, en 10 individuos (11.1 por ciento); enrojecimiento, en ocho (8.8 por ciento), e induración, en seis (6.6 por ciento). Malestar general, cefalea y fiebre se presentaron a los cinco días en 10, 8.8, y 0 por ciento de individuos, respectivamente, y en 4.4, 6.6, y 0 por ciento, respectivamente, a los 28 días. CONCLUSIONES: Esta vacuna contra influenza demostró ser altamente inmunogénica en adultos mexicanos mayores de 55 años de edad. Se demostró también la producción de anticuerpos de alta afinidad contra el virus, posterior a la vacunación. Además, se identificó una frecuencia de reacciones locales y sistémicas similares a las previamente reportadas...

[Stem cell perspectives in myocardial infarctions]. / Perspectivas de las células tallo en infartos del miocardio.

Myocardial infarction is the leading cause of congestive heart failure and death in industrializated countries. The cellular cardiomyoplasty has emerged as an alternative treatment in the regeneration of infarted myocardial tissue. In animals' models, different cellular lines such as cardiomyocites, skeletal myoblasts, embryonic stem cells and adult mesenchymal stem cells have been used, resulting in an improvement in ventricular function and decrease in amount of infarcted tissue. The first three cells lines have disvantages as they are allogenics and are difficult to obtain. The adult mesenchymal stem cells are autologous and can be obtained throught the aspiration of bone marrow or from peripherical circulation, after stimulating with cytokines (G-CSF). The implantation in humans with recent and old myocardial infarction have shown improvements similar to those shown in animal models. These findings encourage the continued investigation in the mechanism of cellular differentiation and implantation methods in infarcted myocardial tissue.

Contribution of cholesteryl ester transfer protein and lecithin:cholesterol acyltransferase to HDL size distribution.

High-density lipoproteins (HDL) includes a heterogeneous class of lipoproteins grouped into various subclasses that seem to have different antiatherogenic function. Cholesteryl ester transfer protein (CETP) and lecithin cholesterol acyltransferase (LCAT) play an active role in HDL remodeling. This study was designed to define the role of CETP and LCAT activities on HDL-cholesterol (HDL-C) plasma levels and HDL size distribution, as determined by nondenaturating polyacrylamide gradient gel electrophoresis in 47 clinically healthy Mexican individuals without personal and family history of coronary heart disease. Surprisingly, plasma activities of CETP (29+/-4.1% of transfer) and LCAT (4.8+/-2.2% of esterification) did not correlate either with HDL-C plasma levels or with any other lipid parameter, indicating the poor contribution of these proteins to the lipid profile. The CETP activity showed a negative correlation with small HDL3b (r = -0476, P < 0.05), whereas LCAT was positively associated with this HDL subclass (r = 0.466, P < 0.05). The LCAT showed a negative correlation with large HDL2a (r = - 0.674, P < 0.005). Nevertheless, when the LCAT/CETP ratio was calculated, we observed that the higher the ratio, the greater the relative proportion of small HDL3b (r = 0.551, P < 0.05) and HDL3c (r = 0.477, P < 0.05). These results suggest that the balance of LCAT and CETP activities have a great impact in the plasma HDL size distribution.

Determinación de la producción de interleucina-1B al estímulo mecánico en osteoblastos humanos cultivados "in vitro" / Determination of the interleukin-1B production by mechanical stimulation in cultured human osteoblastos, in vitro

La remodelación mecánica del hueso es utilizada por los ortodoncistas, quienes ejercen fuerza sobre los dientes para moverlos a través del hueso alveolar; tal remodelación ósea involucra la activación de las células del hueso y la estimulación de la reabsorción y aposición de la matriz ósea. La estimulacion mecánica ha sido reconocida como un factor importante en la remodelación ósea, especialmente durante la erupción de los dientes, en la corrección de las maloclusiones, sin embargo, los aspectos moleculares que se involucran en estos procesos no han sido totalmente entendidos. Se han desarrollado diferentes métodos para aplicar el estímulo mecánico al tejido óseo, in vivo o in vitro, a células humanas, para evaluar el resultado bioquímico. El objetivo de este trabajo fue analizar los efectos de la estimulación mecánica en osteoblastos humanos (Saos-2) cultivados in vitro, con respecto a la producción de interleucina 1 Beta (IL-1B), uno de los pasos involucrados en el proceso de remodelación ósea. En este estudio se desarrolló un método de crecer osteoblastos humanos como línea celular en cajas Petri, donde la base puede ser deformada intermitentemente cada 5 segundos después de 1.5 minutos durante más de 72 horas. La estimulación mcánica de estas células se compara con células no estimuladas (n=5). Los osteoblastos humanos son sembrados para ser confluentes en un medio de cultivo F12 de Dulbeco modificado con un 10 por ciento de suero fetal, 100 ug/mL de estreptomicina, 100U/mL de penicilina y 0.25 ug/mL de anfotericina, en una atmósfera de 95 por ciento de aire y un 5 por ciento de CO2, a 37§C. Utilizando el ensayo de ELISA (Enzyme-linked Immunoassay) se determinó los niveles de producción de IL-1B después de 8, 24, 48 y 72 horas. Los resultados mostraron que no hubo producción de IL-1B después de 8, 24, 48 y 72 horas. Los resultados mostraron que no hubo producción de IL-1B a las 8 horas de estímulo, sin embargo a las 24 (13.5 +- 2.1), 48 (23.2 +- 1.3) y 72 horas (33.9 +- 1.9) se encontró una diferencia estadísticamente significativa comparada con el control (p<0.0001). Estos resultados sugirieron que los osteoblastos humanos cutivados in vitro reaccionan al estímulo mecánico liberando mayor cantidad de IL-1B en comparación con el control y de alguna manera algunos efectos celulares pueden asociarse con la remodelación ósea y el movimiento dentario durante el tratamiento de ortodoncia

Differential expression of a 70 kDa O-glycoprotein on T cells: a possible marker for naive and early activated murine T cells.

We purified a 70 kDa O-glycoprotein that binds to the GalNAc specific lectin from Amaranthus leucocarpus (ALLr) and determined its expression pattern on T lymphocytes from different murine lymphoid organs. High level of ALLr expression was demonstrated in 95-98% of both CD4(+)8(+) and CD4(-)8(+) thymocytes, and in 80-95% of CD8(+) T cells from peripheral blood, lymph nodes, and spleen, whereas a minor fraction of CD4(+)8(-) thymocytes (46-67%) and peripheral CD4(+) T cells (9-40%) showed low ALLr expression. Peripheral CD19(+) B cells were ALLr negative and most of the peripheral ALL(+) T cells showed a CD62L(hi)CD45RB(hi)CD44(lo/-) phenotype, indicating features of naive cells. Mitogenic activation of peripheral T cells increased 3-fold the number of ALL(+)CD4(+) T cells 24 h after stimulation, as opposed to a >80% decrease in CD8(+) T cells 72 h after stimulation. Our results suggest that ALL detects a non-described surface O-glycoprotein selectively expressed by naive CD8(+) T cells and by early activated CD4(+) T cells.

Ceramide promotes the death of human cervical tumor cells in the absence of biochemical and morphological markers of apoptosis.

C8-ceramide, a synthetic cell-permeable analog of endogenous ceramides, interfered with cell proliferation, and was cytotoxic to papilloma virus-containing human cervix carcinoma cells, CALO, INBL, and HeLa, that match two clinical stages of tumor progression. C8-ceramide (3 microM) markedly reduced the tumor cell number after 48 h of treatment, an effect that endured even after the removal of C8-ceramide. The carcinoma cells showed morphologic changes, characteristic of necrosis and released lactate dehydrogenase (LDH). A biologically inactive analog C8-dihydro-ceramide had no effect on cell viability in any of the cell lines tested. Seventy-two hours after C8-ceramide treatment none of the biochemical and morphological markers characteristic of apoptosis: (a) nuclear chromatin condensation, (b) DNA fragmentation, (c) proteolysis of the caspase-3 substrate poly-(ADP-ribose)-polymerase (PARP), and (d) appearance of phosphatidylserine on the external cell membrane, were observed. C8-ceramide had no effect on human cervix fibroblasts and induced a mild reduction (30%) in the proliferation of normal human cervix epithelia and HeLa cells (IV-B metastatic stage). The cytotoxicity of C8-ceramide was restricted to CALO (early II-B) and INBL (IV-A non-metastatic) carcinoma cells. The possible application of ceramide in the treatment of early stages of cervical cancer is discussed.

Participación del factor de necrosis tumoral-a en la aterosclerosis / Participation of the tumor necrosis factor alpha in atherosclerosis

La presente revisión menciona las características del factor de necrosis tumoral-a y el papel que esta citocina juega en el desarrollo de la lesión ateromatosa. Se describe, al detalle los efectos que tiene esta citocina sobre células endoteliales vasculares en condiciones normales así como de alto riesgo. Se propone que el TNF-a posee un papel central en el desarrollo inicial y en el progreso de la placa ateromatosa debido a que al afectarse los mecanismos de autorregulación de la célula endotelial la concentración de TNF-a se eleva de manera importante a nivel local generando, junto con la presencia local de diversos factores conocidos de riesgo, un microambiente autoperpetuable que favorece el desarrollo de la lesion ateromatosa.

Análisis estructural de las mucinas y su relevancia como receptor de agentes infecciosos / Structural analysis of mucins and their relevance as infectious agents receptor

La mucina es una glicoproteína de elevado peso molecular que se caracteriza por poseer complejas cadenas de oligosacáridos unidos a la proteína por enlaces O-glicosídicos. Se ha observado que estas glicoproteínas, que sirven como receptor de diversos agentes infecciosos, que sirven como receptor de diversos agentes infecciosos, se modifican estructural y funcionalmente como respuesta a procesos inflamatorios o de degeneración cancerosa. Su estudio está limitado por la polidispersión de la mucina, sin embargo en este trabajo se presentan diversos marcadores moleculares específicos para carbohidratos que permiten evidenciar tales transformaciones.