RESUMEN
The TOTEM collaboration has measured the proton-proton total cross section at âs=8 TeV using a luminosity-independent method. In LHC fills with dedicated beam optics, the Roman pots have been inserted very close to the beam allowing the detection of ~90% of the nuclear elastic scattering events. Simultaneously the inelastic scattering rate has been measured by the T1 and T2 telescopes. By applying the optical theorem, the total proton-proton cross section of (101.7±2.9) mb has been determined, well in agreement with the extrapolation from lower energies. This method also allows one to derive the luminosity-independent elastic and inelastic cross sections: σ(el)=(27.1±1.4) mb; σ(inel)=(74.7±1.7) mb.
RESUMEN
The first double diffractive cross-section measurement in the very forward region has been carried out by the TOTEM experiment at the LHC with a center-of-mass energy of sqrt[s]=7 TeV. By utilizing the very forward TOTEM tracking detectors T1 and T2, which extend up to |η|=6.5, a clean sample of double diffractive pp events was extracted. From these events, we determined the cross section σDD=(116±25) µb for events where both diffractive systems have 4.7<|η|min<6.5.
RESUMEN
Arsenic (As) contamination is an important environmental consequence in some parts of salinity-affected South (S) and South-East (SE) Asia. In this study, we investigated the individual and combined phytotoxicity of arsenic (As) [arsenate; As(V)] and salinity (NaCl) on early seedling growth (ESG) of saline-tolerant and non-tolerant rice varieties. Germination percentage (GP), germination speed (GS) and vigor index (VI) of both saline-tolerant and non-tolerant rice varieties decreased significantly (p > 0.01) with increasing As(V) and NaCl concentrations. The highest GP (91%) was observed for saline non-tolerant BRRI dhan28 and BRRI dhan49, while the lowest (62%) was for saline-tolerant BRRI dhan47. The ESG parameters, such as weights and relative lengths of plumule and radicle, also decreased significantly (p < 0.01) with increasing As(V) and NaCl concentrations. Relative radicle length was more affected than plumule length by As(V) and NaCl. Although VI of saline-tolerant and non-tolerant rice seedlings showed significant variation (p < 0.05), weights and lengths of plumule and radicle of different rice varieties did not show significant variation for As(V) and NaCl treatments. Results reveal that the combined phytotoxicity of As(V) and NaCl on rice seed germination and ESG are greater than their individual toxicities, and some saline-tolerant rice varieties are more resistant to the combined phytotoxicity of As(V) and NaCl than the saline non-tolerant varieties.
Asunto(s)
Arseniatos/toxicidad , Oryza/efectos de los fármacos , Salinidad , Plantones/efectos de los fármacos , Contaminantes del Suelo/toxicidad , Agricultura/métodos , Asia Sudoriental , Bangladesh , Conservación de los Recursos Naturales , Germinación/efectos de los fármacos , Agua Subterránea/química , Oryza/crecimiento & desarrollo , Oryza/fisiología , Plantones/crecimiento & desarrollo , Plantones/fisiología , Suelo/químicaRESUMEN
Airway hyperresponsiveness (AHR) is a hallmark of asthma and a heritable polygenic trait in the mouse. In the mouse, candidate gene products of hematopoietic origin implicated in asthma mapped to the regions of the previously defined quantitative trait loci. Since hematopoietic cells have been implicated in the pathogenesis of asthma, we evaluated the role of hematopoietic cells in general and T cells specifically in the genetic modulation of native airway responsiveness in mice. Here, with the use of bone marrow transplantation, anti-T-cell monoclonal antibody treatment and T-cell transfer, we demonstrate that intrinsic non-atopic AHR is mediated by T lymphocytes. Our data support the novel concept that, in the absence of identified environmental influences, T cells enhance genetically determined airway responsiveness.
Asunto(s)
Asma/genética , Asma/inmunología , Sistema Respiratorio/inmunología , Linfocitos T/inmunología , Traslado Adoptivo , Resistencia de las Vías Respiratorias/efectos de los fármacos , Animales , Asma/etiología , Trasplante de Médula Ósea , Broncoconstrictores/farmacología , Relación Dosis-Respuesta a Droga , Depleción Linfocítica , Masculino , Cloruro de Metacolina/farmacología , Ratones , Ratones Endogámicos C57BL , Modelos Biológicos , Especificidad de la Especie , TimectomíaRESUMEN
We examined if suppressor cell clones may be established from adult bone marrow that contains a population of cells capable of specifically downregulating the immune response directed toward self-major histocompatibility complex (MHC) antigens. Freshly prepared adult C3H (H-2k) marrow cells were cultured in medium containing interleukin 2 (IL-2), IL-3, or a mixture of IL-2 and IL-3. After 7-10 d, cells grown in IL-3-containing medium were screened for their capacity to suppress cytotoxic T lymphocyte (CTL) generation against self-MHC antigens in allogeneic mixed lymphocyte cultures. Cells capable of suppressing anti-C3H CTL generation were cloned by limiting dilution. Several suppressor clones were established that exhibited strong suppression of anti-H-2k, anti-H-2Kk/Ik, and anti-H-2Dk CTL generation, but failed to suppress anti-H-2d and anti-H-2b responses. When tested in a skin allograft model, intravenous injections of these bone marrow-derived anti-self suppressor cells (2.5 x 10(7) cells) together with IL-3 induced prolongation of C3H skin allografts in anti-mouse lymphocyte serum-treated B6AF1 mice. Injection of IL-3 alone had no effect on allograft survival. Moreover, these cells failed to prolong B10.AKM skin allografts on B6AF1 recipients. Northern blot analysis showed that these cells express full-length transcripts of the T cell receptor (TCR) gamma gene, but not those of TCR alpha, beta, or delta genes. However, no rearrangement of gamma gene was observed by Southern blot analysis. Flow cytometric analysis revealed that bone marrow-derived suppressor cells are strongly positive for Thy-1 antigen but negative for CD3, CD4 (L3T4), and CD8 (Lyt-2) surface markers, and express only class I MHC antigens. Suppressor cells derived from adult bone marrow may play an important role in extrathymic induction of self-tolerance.
Asunto(s)
Médula Ósea/inmunología , Complejo Mayor de Histocompatibilidad , Linfocitos T Reguladores/inmunología , Animales , Anticuerpos Monoclonales , Northern Blotting , Southern Blotting , Línea Celular , Células Cultivadas , Citotoxicidad Inmunológica , ADN/genética , ADN/aislamiento & purificación , Citometría de Flujo , Prueba de Cultivo Mixto de Linfocitos , Ratones , Ratones Endogámicos C3H , Ratones Endogámicos C57BL , Ratones Endogámicos DBA , Ratones Endogámicos , Receptores de Antígenos de Linfocitos T/genética , Trasplante de Piel/inmunología , Linfocitos T Reguladores/citologíaRESUMEN
Ischemia/reperfusion injury and delayed graft function (DGF) following organ transplantation adversely affect graft function and survival. A large animal model has not been characterized. We developed a pig kidney allograft model of DGF and evaluated the cytoprotective effects of inhaled carbon monoxide (CO). We demonstrate that donor warm ischemia time is a critical determinant of DGF as evidenced by a transient (4-6 days) increase in serum creatinine and blood urea nitrogen following transplantation before returning to baseline. CO administered to recipients intraoperatively for 1 h restored kidney function more rapidly versus air-treated controls. CO reduced acute tubular necrosis, apoptosis, tissue factor expression and P-selectin expression and enhanced proliferative repair as measured by phosphorylation of retinol binding protein and histone H3. Gene microarray analyses with confirmatory PCR of biopsy specimens showed that CO blocked proinflammatory gene expression of MCP-1 and heat shock proteins. In vitro in pig renal epithelial cells, CO blocks anoxia-reoxygenation-induced cell death while promoting proliferation. This large animal model of DGF can be utilized for testing therapeutic strategies to reduce or prevent DGF in humans. The efficacy of CO on improving graft function posttransplant validates the model and offers a potentially important therapeutic strategy to improve transplant outcomes.
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Monóxido de Carbono/uso terapéutico , Funcionamiento Retardado del Injerto/tratamiento farmacológico , Trasplante de Riñón/fisiología , Animales , Monóxido de Carbono/farmacocinética , Muerte Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Femenino , Perfilación de la Expresión Génica , Rechazo de Injerto/prevención & control , Riñón/metabolismo , Necrosis Tubular Aguda/etiología , Necrosis Tubular Aguda/inmunología , Daño por Reperfusión/prevención & control , Porcinos , Tacrolimus/farmacocinéticaRESUMEN
Descriptive information on platelet (PLT) recipients, particularly during surgery, is limited. A description of the current epidemiology of PLT-transfused patients is required to optimize platelet transfusion care and to follow trends in PLT use. In 2004 and 2005, information was combined from several computerized medical systems. Participating hospitals (9 hospital districts of 21) handled approximately 64% of annual Finnish hospital admissions. A total of 6321 adult patients were transfused with 37,761 PLT products. Most PLT products (43.1%) were transfused to patients suffering from haematological malignancies. Only 1.0% of all surgical patients received PLTs (53.8% of PLT recipients and 35.8% of transfused PLTs). The most common single operation connected with PLT transfusion was coronary artery bypass while 27.1% of surgery-related PLTs were given to patients having an operation involving the digestive system or spleen. Only 36.4% of all PLT-transfused (operated and conservatively treated) patients were discharged directly home; in-hospital mortality was 9.5%. PLTs were given 40 products per 1000 hospital admissions requiring an operation in 2004, and 38 products in 2005. Perioperative PLT use is slightly decreasing in adult patients. As a single-operation type, coronary artery bypass patients receive most of the PLT products and have experienced no decline in PLT use over the years. Overall, PLT recipients have high in-hospital mortality.
Asunto(s)
Transfusión de Plaquetas/estadística & datos numéricos , Procedimientos Quirúrgicos Operativos , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Grupos Diagnósticos Relacionados , Femenino , Finlandia/epidemiología , Mortalidad Hospitalaria , Hospitales de Distrito/estadística & datos numéricos , Hospitales Universitarios/estadística & datos numéricos , Humanos , Clasificación Internacional de Enfermedades , Cuidados Intraoperatorios/estadística & datos numéricos , Masculino , Persona de Mediana Edad , Transfusión de Plaquetas/tendencias , Cuidados Preoperatorios/estadística & datos numéricos , Adulto JovenRESUMEN
1. It has been reported that karaya saponin and Rhodobacter capsulatus individually have hypocholesterolaemic activity in laying hens. This study focuses on the effect of adding karaya saponin with R. capsulatus to hen's diet with regard to serum and egg yolk cholesterol and triglycerides. 2. A total of 56 Boris Brown laying hens were divided into 7 groups at 20 weeks of age. Combinations of 25, 50, 75 mg kg(-1) karaya saponin and R. capsulatus 200 and 400 mg kg(-1) were used as treatment groups. 3. After 8 weeks of supplementation, the effects of all the combinations of karaya saponin and R. capsulatus on serum and egg yolk cholesterol, triglycerides, and high-density lipoprotein (HDL)-cholesterol were greater than either karaya saponin or R. capsulatus alone. The combination of karaya saponin 50 mg kg(-1)+ R. capsulatus 400 mg kg(-1) exhibited the greatest reduction of serum (325%) and yolk (225%) cholesterol and the greatest increase of faecal, liver bile acids and yolk fatty acid (oleic, linoleic and linolenic) concentrations. In addition, egg production and yolk colour were significantly improved by the combined use of karaya saponin and R. capsulatus supplementation. 4. Therefore, the dietary supplementation of karaya saponin and R. capsulatus may lead to the production of a low-cholesterol egg, with production performance maintained at a standard level.
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Pollos/metabolismo , Colesterol/metabolismo , Yema de Huevo/efectos de los fármacos , Metabolismo de los Lípidos/efectos de los fármacos , Probióticos/farmacología , Rhodobacter capsulatus , Saponinas/farmacología , Sterculia/química , Alimentación Animal , Animales , Pollos/sangre , Colesterol/sangre , Dieta/veterinaria , Yema de Huevo/metabolismo , Femenino , Óvulo/metabolismo , Saponinas/aislamiento & purificación , Triglicéridos/sangre , Triglicéridos/metabolismoRESUMEN
Diabetic complications such as neuropathy, retinopathy, and renal and cardiovascular disease continue to pose major health risks for diabetic patients. Consequently, much effort has focused on approaches that could replace conventional insulin therapy and provide more precise regulation of blood glucose levels. The biohybrid perfused artificial pancreas was designed to incorporate islet tissue and a selectively permeable membrane that isolates this tissue from the immune system of the recipient. Biohybrid pancreas devices containing canine islet allografts were implanted in ten pancreatectomized dogs requiring 18 to 32 units of injected insulin daily. These implants resulted in good control of fasting glucose levels in six of these animals without further exogenous insulin for periods of up to 5 months.
Asunto(s)
Diabetes Mellitus Experimental/terapia , Trasplante de Islotes Pancreáticos , Prótesis e Implantes , Animales , Glucemia/metabolismo , Bovinos , Diabetes Mellitus Experimental/sangre , Perros , Insulina/metabolismo , Secreción de Insulina , Islotes Pancreáticos/metabolismo , Pancreatectomía , Trasplante Heterólogo , Trasplante HomólogoRESUMEN
The purpose of this study was to attempt to find related variables of the canine genome with behavioural traits of dogs maintained and tested in a guide dog facility which provided a relatively uniform environment. The study involved 81 Labrador Retrievers that were being trained as guide dogs. Each dog was taken on walk-out sessions in which the trainer weekly recorded observations that were related to behavioural traits. The records were subjected to key-word analysis of 14 behaviour-related words. A factor analysis on the appearance rate of the 14 key words or phrases resulted in the extraction of six factors that accounted for 67.4% of the variance. Factor 1, referred to as aggressiveness, was significantly related to the success or failure of the dog in qualifying as a guide dog, and was also related to the variable of litter identification. Factor 2, referred to as distraction, was related to the variable of trainer. Factor 3, activity level, was related to the variable of sex, and was significantly related to the polymorphisms of c.471T>C in the solute carrier family 1 (neuronal/epithelial high affinity glutamate transporter) member 2 gene and c.216G>A in the catechol-O-methyltransferase gene. The involvement of polymorphisms c.471T>C and c.216G>A in behavioural patterns related to activity level is similar to comparable genetic studies in other mammalian species. These results contribute to a greater understanding of the role of these genes in behaviour.
Asunto(s)
Conducta Animal , Ceguera/rehabilitación , Perros/genética , Perros/psicología , Genética Conductual , Animales , Femenino , Genoma , Humanos , Masculino , Polimorfismo Genético , Polimorfismo de Nucleótido SimpleRESUMEN
The relationships between behavioural trait data and the genotype of 15 polymorphisms in eight neurotransmitter-related genes were analysed in 77 dogs of the Shiba Inu breed, an indigenous Japanese dog. The data were obtained from a 26-item questionnaire on the dog's behaviour, distributed to the dog's owners, through veterinary hospitals and the Shiba Inu breed magazine. A factor analysis of the questionnaire items extracted eight factors accounting for 66.8% of the variance. An association analysis between these factors and genetic polymorphisms indicated that the polymorphism of c.471T>C in the solute carrier family 1 (neuronal/epithelial high-affinity glutamate transporter) member 2 (SLC1A2) gene was significantly associated with Factor 1, referred to as 'aggression to strangers'. This association remained stable in separate analyses of data from surveys obtained from the hospitals and those obtained from the magazine. The results suggest that the c.471T>C polymorphism is associated with some types of aggressive behaviour in the Shiba Inu. Further studies using other dog breeds are necessary to extend these findings to dogs in general.
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Agresión , Conducta Animal/fisiología , Perros/genética , Transportador 2 de Aminoácidos Excitadores/genética , Polimorfismo Genético , Animales , Perros/fisiología , Análisis Factorial , Femenino , Genotipo , Japón , Masculino , Especificidad de la Especie , Encuestas y CuestionariosRESUMEN
Effects of eutrophication on arsenic speciation were studied in eutrophic Lake Kiba and mesotrophic Lake Biwa, Japan. By combining hydride generation atomic absorption spectrometry with ultraviolet irradiation, inorganic, methyl and ultraviolet-labile fractions of arsenic were determined. In both Lakes, inorganic species (As(V+III)) dominated over other forms of arsenic all the year round. Most of methylarsenic fraction was dimethylarsinic acid (DMAA), and the concentration of monomethylarsonic acid (MMAA) was below the detection limit. Measurements of size-fractioned arsenic concentrations in water column indicate that most of the DMAA was distributed in truly dissolved fraction (<10 kDa), while ultraviolet-labile fractions were distributed in particulate (>0.45 microm) and colloidal (10 kDa-0.45 microm) fractions. Arsenic speciation in eutrophic Lake Kiba fluctuated greatly with season. The ultraviolet-labile fractions were observed with the increase of DMAA from May to October, and they disappeared with the decrease of DMAA in January. In mesotrophic Lake Biwa, the ultraviolet-labile fractions of arsenic were not influenced as much as those in eutrophic Lake Kiba. On the other hand DMAA concentration was higher in Lake Biwa compared to that in Lake Kiba. The results suggest that the biosynthesis of complex organoarsenicals was enhanced by eutrophication, and the arsenic speciation would be influenced by the balance of biological processes in natural waters.
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Arsenicales/análisis , Eutrofización , Contaminantes Químicos del Agua/análisis , Agua Dulce , Estaciones del Año , Espectrofotometría AtómicaRESUMEN
Alloreactive memory T cells mediate accelerated rejection. We investigated the effect of polyclonal anti-T-cell antibody (ALS) and rapamycin (RAPA) on skin allograft survival in naïve or alloantigen-primed mice. ALS prolonged graft survival in both naïve and alloantigen-primed mice. T-cell depletion by ALS was associated with increased CD4(+)CD44(hi)OX40(+) and CD8(+)CD44(hi)CD122(+) memory T cells. Addition of RAPA to ALS extended graft survival in naïve mice, but had no effect on secondary allograft survival in alloantigen-primed mice. In adoptive transfer experiments, RAPA inhibited alloantigen-stimulated proliferation and allograft rejection by naïve T cells. In contrast, alloantigen-primed memory T cells, particularly CD4(+)CD44(hi)OX40(+) and CD8(+)CD44(hi)CD122(+) T cells, were resistant to RAPA in response to alloantigen and mediated accelerated rejection in the presence of RAPA. Resistance to RAPA by alloantigen-primed mice was overcome by the use of high-dose ALS, which achieved marked prolongation of secondary skin allograft survival (>100 days). Inhibition of CD122(+) T cells and/or OX40/OX40L costimulation blockade, combined with low-dose ALS and RAPA, was also effective. These results demonstrate that tolerance may be achieved in allosensitized individuals by T-cell depletion- and RAPA-based strategies employing high-dose ALS or targeting CD122(+)CD8(+) T cells and/or the OX40/OX40L costimulatory pathway.
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Supervivencia de Injerto , Isoanticuerpos/uso terapéutico , Trasplante de Piel/inmunología , Linfocitos T/inmunología , Animales , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD8-positivos , Rechazo de Injerto/inmunología , Rechazo de Injerto/prevención & control , Memoria Inmunológica , Ganglios Linfáticos/inmunología , Ratones , Ratones Endogámicos DBA , Ratones Endogámicos , Modelos Animales , Sirolimus/uso terapéutico , Trasplante de Piel/patología , Trasplante de Piel/fisiología , Trasplante HomólogoRESUMEN
BACKGROUND: Tobacco use interventions in surgical patients who smoke could benefit both their short-term outcome and long-term health. Anaesthesiologists and surgeons can play key roles in delivering these interventions. This study determined the practices, attitudes, and beliefs of these physicians regarding tobacco use interventions in Japan. METHODS: Questionnaires were mailed to a national random sampling of Japanese anaesthesiologists and thoracic surgeons (1000 in each group). RESULTS: The survey response rate was 62%. More than 80% of respondents agreed or strongly agreed with the statements affirming the benefits of abstinence to surgical patients. However, only 26% of surgeons and 6% of anaesthesiologists reported almost always providing help to their patients to quit smoking. Compared with anaesthesiologists, surgeons were more likely to perform the elements of current recommendations for brief intervention, and to have attitudes favourable to tobacco use interventions. The most significant barrier to intervention identified by both groups was a lack of time to perform counselling. Compared with non-smokers, physicians who smoked were less likely to perform each of the recommended tobacco interventions CONCLUSIONS: Although current rates of intervention provided by anaesthesiologists and surgeons are low, there is considerable interest among these physicians in learning more about interventions. Given the relatively high prevalence of smoking in Japan and the potential for surgery to serve as a 'teachable moment' to promote abstinence from smoking, leadership by these specialists in the area of tobacco control could have a major impact on public health in Japan.
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Actitud del Personal de Salud , Educación del Paciente como Asunto/métodos , Cese del Hábito de Fumar/estadística & datos numéricos , Prevención del Hábito de Fumar , Procedimientos Quirúrgicos Torácicos , Adulto , Anestesiología , Competencia Clínica , Consejo/estadística & datos numéricos , Femenino , Encuestas de Atención de la Salud , Humanos , Japón , Masculino , Persona de Mediana Edad , Atención Perioperativa/métodos , Práctica Profesional/estadística & datos numéricos , Fumar/psicologíaRESUMEN
The adsorption of Au(III), Pt(IV) and Pd(II) onto glycine modified crosslinked chitosan resin (GMCCR) has been investigated. The parameters studied include the effects of pH, contact time, ionic strength and the initial metal ion concentrations by batch method. The optimal pH for the adsorption of Au(III), Pt(IV) and Pd(II) was found to range from 1.0 to 4.0 and the maximum uptake was obtained at pH 2.0 for Au(III), Pt(IV) and Pd(II). The results obtained from equilibrium adsorption studies are fitted in various adsorption models such as Langmuir and Freundlich and the model parameters have been evaluated. The maximum adsorption capacity of GMCCR for Au(III), Pt(IV) and Pd(II) was found to be 169.98, 122.47 and 120.39mg/g, respectively. The kinetic data was tested using pseudo-first-order and pseudo-second-order kinetic models and an intraparticle diffusion model. The correlation results suggested that the pseudo-second-order model was the best choice among all the kinetic models to describe the adsorption behavior of Au(III), Pt(IV) and Pd(II) onto GMCCR. Various concentrations of HCl, thiourea and thiourea-HCl solutions were used to desorb the adsorbed precious metal ions from GMCCR. It was found that 0.7M thiourea-2M HCl solution provided effectiveness of the desorption of Au(III), Pt(IV) and Pd(II) from GMCCR. The modification of glycine on crosslinked chitosan resin (CCR) was studied by Fourier transform infrared spectrometry (FTIR) and scanning electron microscopy (SEM).
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Quitosano/química , Reactivos de Enlaces Cruzados/farmacología , Glicina/química , Oro/aislamiento & purificación , Paladio/aislamiento & purificación , Platino (Metal)/aislamiento & purificación , Resinas Sintéticas/química , Adsorción/efectos de los fármacos , Cloruros , Difusión/efectos de los fármacos , Concentración de Iones de Hidrógeno/efectos de los fármacos , Cinética , Concentración Osmolar , Temperatura , Factores de TiempoRESUMEN
The influence of ethylenediaminetetraacetic acid (EDTA) and chemical species on arsenic accumulation in aquatic floating macrophyte Spirodela polyrhiza L. (duckweed) was investigated. The uptake of inorganic arsenic species (arsenate; As(V) and arsenite; As(III)) into the plant tissue and their adsorption on iron plaque of plant surfaces were significantly (p<0.05) higher than those of organic species (monomethylarsonic acid (MMAA) and dimethylarsinic acid (DMAA)). The addition of EDTA to the culture media increased the uptake of As(V) and As(III) into the plant tissue though the MMAA and DMAA uptake were not affected. About 4-6% of the inorganic arsenic species were desorbed or mobilized from iron plaque by EDTA. Desorption of organic arsenic species was not affected by EDTA addition because the co-precipitation occurs only with inorganic species. Phosphate uptake was not affected by EDTA though its concentration in citrate-bicarbonate-EDTA (CBE)-extract was much higher than that of plant tissue. Iron uptake into the plant increased significantly (p>0.05) by EDTA addition to the culture media while its concentration in CBE-extract decreased significantly (p<0.05). The As(inorganic)/Fe ratios in plant were higher than those of CBE-extract which indicate the increased uptake of these arsenic species into the plant relative to the iron. The lower As(organic)/Fe ratios in plant and on CBE-extract suggest the reduction of accumulation of these arsenic species relative to the iron.
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Araceae/efectos de los fármacos , Arsenicales/metabolismo , Quelantes/farmacología , Ácido Edético/farmacología , Contaminantes Químicos del Agua/metabolismo , Adsorción , Araceae/química , Araceae/metabolismo , Arsenicales/química , Hierro/química , Hierro/metabolismo , Fósforo/metabolismo , Hojas de la Planta/química , Hojas de la Planta/efectos de los fármacos , Hojas de la Planta/metabolismo , Raíces de Plantas/química , Raíces de Plantas/efectos de los fármacos , Raíces de Plantas/metabolismoRESUMEN
The uptake of arsenate (As(V)) and dimethylarsinic acid (DMAA) by aquatic macrophyte Spirodela polyrhiza L. was investigated to determine the influence of arsenic interaction with PO4(3-) and Fe ions. Plants were grown hydroponically on standard Murashige and Skoog (MS) culture solutions. Arsenic concentrations in Fe-oxide (Fe-plaque) on plant surfaces were determined by citrate-bicarbonate-ethylenediaminetetraacetic acid (CBE) technique. S. polyrhiza L. accumulated 51-fold arsenic from arsenate solution compared to that from DMAA solution with initial concentrations of 4.0 and 0.02microM of arsenic and phosphate, respectively. The arsenate uptake was negatively (p<0.001) correlated with phosphate uptake and positively (p<0.05) correlated with iron uptake. About 56% of the total arsenic was accumulated into the plant tissues while 44% was adsorbed on Fe-plaque (CBE-extract), when the plants were grown on arsenate solution. The DMAA uptake into the plant was neither affected by the phosphate concentrations nor correlated (p>0.05) with iron accumulation. The results suggest that adsorption of arsenate on Fe-plaque of the surface of S. polyrhiza L. contributes to the arsenic uptake significantly. Thus, arsenate uptake in S. polyrhiza L. occurred through the phosphate uptake pathway and by physico-chemical adsorption on Fe-plaques of plant surfaces as well. The S. polyrhiza L. uses different mechanisms for DMAA uptake.
Asunto(s)
Arsenicales/metabolismo , Hierro/química , Fosfatos/química , Plantas/metabolismo , Arseniatos/química , Bicarbonatos/química , Ácido Cacodílico/química , Quelantes/química , Citratos/química , Interpretación Estadística de Datos , Ácido Edético/química , Compuestos Férricos/química , Raíces de Plantas/química , Plantas/química , Espectrofotometría AtómicaRESUMEN
Transforming growth factor-beta 1 (TGF-beta 1) is a peptide growth factor that may play a role in the myocardial response to hypertrophic stimuli. However, the cellular distribution, mechanism of induction, and source of increased TGF-beta 1 in response to hypertrophic stimuli are not known. We tested the hypothesis that the cardiac myocyte responds to hypertrophic stimuli with the increased expression of TGF-beta 1. In adult rat ventricular myocardium freshly dissociated into myocyte and nonmyocyte cellular fractions, the preponderance of TGF-beta 1 mRNA visualized by Northern hybridization was in the nonmyocyte fraction. Abdominal aortic constriction (7 d) and subcutaneous norepinephrine infusion (36 h) each caused ventricular hypertrophy associated with 3.1-fold and 3.8-fold increases, respectively, in TGF-beta 1 mRNA in the myocyte fraction, but had no effect on the level of TGF-beta 1 mRNA in the nonmyocyte fraction. In ventricular myocytes, norepinephrine likewise caused a 4.1-fold increase in TGF-beta 1 mRNA associated with an increase in TGF-beta bioactivity. This induction of TGF-beta 1 mRNA occurred at norepinephrine concentrations as low as 1 nM and was blocked by prazosin, but not propranolol. NE did not increase the TGF-beta 1 mRNA level in nonmyocytes, primarily fibroblasts, cultured from neonatal rat ventricle. Thus, the cardiac myocyte responds to two hypertrophic stimuli, pressure overload and norepinephrine, with the induction of TGF-beta 1. These data support the view that TGF-beta 1, released by myocytes and acting in an autocrine and/or paracrine manner, is involved in myocardial remodeling by hypertrophic stimuli.
Asunto(s)
Cardiomegalia/metabolismo , Miocardio/metabolismo , Norepinefrina/farmacología , Factor de Crecimiento Transformador beta/biosíntesis , Animales , Animales Recién Nacidos , Aorta Abdominal , Factor Natriurético Atrial/biosíntesis , Factor Natriurético Atrial/genética , Cardiomegalia/etiología , Células Cultivadas , Constricción Patológica , Medios de Cultivo Condicionados/farmacología , Fibroblastos/metabolismo , Ventrículos Cardíacos , Masculino , Miocardio/citología , Prazosina/farmacología , Propranolol/farmacología , ARN Mensajero/biosíntesis , Ratas , Ratas Sprague-Dawley , Factor de Crecimiento Transformador beta/genética , Regulación hacia Arriba/efectos de los fármacosRESUMEN
Pancreatic islet transplantation represents a potential treatment for insulin-dependent diabetes mellitus. However, the precise cellular and molecular mechanisms of the immune reactions against allogeneic and xenogeneic transplanted islets remain unclear. Here, we demonstrate that CD4(+) Valpha14 natural killer T (NKT) cells, a recently identified lymphoid cell lineage, are required for the acceptance of intrahepatic rat islet xenografts. An anti-CD4 mAb, administrated after transplantation, allowed islet xenografts to be accepted by C57BL/6 mice, with no need for immunosuppressive drugs. The dose of anti-CD4 mAb was critical, and the beneficial effect appeared to be associated with the reappearance of CD4(+) NKT cells at around 14 days after transplantation. Interestingly, rat islet xenografts were rejected, despite the anti-CD4 mAb treatment, in Valpha14 NKT cell-deficient mice, which exhibit the normal complement of conventional lymphoid cells; adoptive transfer of Valpha14 NKT cells into Valpha14 NKT cell-deficient mice restored the acceptance of rat islet xenografts. In addition, rat islet xenografts were accepted by Valpha14 NKT mice having only Valpha14 NKT cells and no other lymphoid cells. These results indicate that Valpha14 NKT cells play a crucial role in the acceptance of rat islet xenografts in mice treated with anti-CD4 antibody, probably by serving as immunosuppressive regulatory cells.
Asunto(s)
Antígenos CD4/inmunología , Supervivencia de Injerto/inmunología , Tolerancia Inmunológica , Trasplante de Islotes Pancreáticos/inmunología , Células Asesinas Naturales/inmunología , Hígado/inmunología , Linfocitos T Colaboradores-Inductores/inmunología , Trasplante Heterólogo/inmunología , Animales , Complejo CD3/análisis , Antígenos CD4/análisis , Hígado/citología , Ratones , Ratones Endogámicos C57BL , Ratas , Ratas Endogámicas Lew , Factores de TiempoRESUMEN
One of the trophic factors that has been implicated in initiating or facilitating growth in response to increased mechanical stress in several tissues and cell types is basic fibroblast growth factor (bFGF; FGF-2). Although mammalian cardiac muscle cells express bFGF, it is not known whether it plays a role in mediating cardiac adaptation to increased load, nor how release of the cytosolic 18-kD isoform of bFGF would be regulated in response to increased mechanical stress. To test the hypothesis that increased mechanical activity induces transient alterations in sarcolemmal permeability that allow cytosolic bFGF to be released and subsequently to act as an autocrine and paracrine growth stimulus, we examined primary isolates of adult rat ventricular myocytes maintained in serum-free, defined medium that were continually paced at 3 Hz for up to 5 d. Paced myocytes, but not nonpaced control cells, exhibited a "hypertrophic" response, which was characterized by increases in the rate of phenylalanine incorporation, total cellular protein content, and cell size. These changes could be mimicked in control cells by exogenous recombinant bFGF and could be blocked in continually paced cells by a specific neutralizing anti-bFGF antibody. In addition, medium conditioned by continually paced myocytes contained significantly more bFGF measured by ELISA and more mitogenic activity for 3T3 cells, activity that could be reduced by a neutralizing anti-bFGF antibody. The hypothesis that transient membrane disruptions sufficient to allow release of cytosolic bFGF occur in paced myocytes was examined by monitoring the rate of uptake into myocytes from the medium of 10-kD dextran linked to fluorescein. Paced myocytes exhibited a significantly higher rate of fluoresceinlabeled dextran uptake. These data are consistent with the hypothesis that nonlethal, transient alterations in sarcolemmal membrane permeability with release of cytosolic bFGF is one mechanism by which increased mechanical activity could lead to a hypertrophic response in cardiac myocytes.