RESUMEN
ZnO/V2O5 nanocomposite thin films were synthesised by the spray pyrolysis technique with optimised deposition parameters by varying the concentration of vanadium pentoxide. The X-ray diffraction results showed that the ZnO/V2O5 nanocomposite thin films have a Wurtzite-type hexagonal ZnO structure. We attained crystal phases at all concentrations. These results indicated that the two crystal phases of pure zinc oxide and vanadium pentoxide exist together within the composite thin film matrix. The morphology was investigated with field emission scanning electron microscopy and transmission electron microscopy (TEM). The microstructures of the deposited thin films were confirmed by Raman spectroscopy. The optical characterizations of the prepared samples were investigated by using a UV-vis spectrophotometer. X-ray photoelectron spectroscopy (XPS) was carried out to confirm the oxidation states of the elements existing on the surface of the composite thin films. The gas-sensing properties of the composite thin films towards toluene gas were studied at the temperature of 27 °C. The sensing mechanism for toluene gas was reported; the response and recovery times were determined from the transient response curve and were found to be 24 s and 28 s, respectively, for the optimised composite film.
RESUMEN
We report the first thermoelectric properties of Cu1-xAgxS, x = 0-0.75 nanocomposites, synthesized by using a facile polyol method. Systematic characterizations using powder XRD, Rietveld refinement of XRD, EDAX, XPS and Raman spectroscopy confirmed their single phase, hexagonal crystal structure with the space group P63/mmc, nominal elemental composition, valence states of the constituent elements and stoichiometric nature. The TEM images showing the CuS formation of nearly perfect hexagonal disk-like particles of average thickness 26.7 nm and breadth ranging in a few hundreds of nanometers with nanorods stacked from these hexagonal nanodisks (NDs) elongated along the c axis corroborate the FESEM images. Attributed to structural phase transition, an anomaly at 55 K is clearly observed in both the thermopower and Hall resistivity data. By increasing x, a systematic reduction in thermal conductivity was observed near 300 K. Consequently, a 50% enhancement in figure of merit was observed for Cu0.9Ag0.1S as compared to pure CuS at 300 K. These results therefore are expected to provide a new direction in improving ZT near 300 K.
RESUMEN
X-ray absorption near-edge structure (XANES) and X-ray photoelectron spectroscopy (XPS) of Nd-doped phosphate glasses have been studied before and after gamma irradiation. The intensity and the location of the white line peak of the L3-edge XANES of Nd are found to be dependent on the ratio O/Nd in the glass matrix. Gamma irradiation changes the elemental concentration of atoms in the glass matrix, which affects the peak intensity of the white line due to changes in the covalence of the chemical bonds with Nd atoms in the glass (structural changes). Sharpening of the Nd 3d5/2 peak profile in XPS spectra indicates a deficiency of oxygen in the glasses after gamma irradiation, which is supported by energy-dispersive X-ray spectroscopy measurements. The ratio of non-bridging oxygen to total oxygen in the glass after gamma radiation has been found to be correlated to the concentration of defects in the glass samples, which are responsible for its radiation resistance as well as for its coloration.
RESUMEN
In the 1990s, drug resistance has become an important problem in a variety of infectious diseases including human immunodeficiency virus infection, tuberculosis, and other bacterial infections which have profound effects on human health. At the same time, there have been dramatic increase in the incidence of fungal infections, which are probably the result of alterations in immune status associated with the acquired immuno deficiency syndrome epidemic, cancer chemotherapy, and organ and bone marrow transplantation. The rise in the incidence of fungal infections has exacerbated the need for the next generation of antifungal agents, since many of the currently available drugs have undesirable side effects, are ineffective against new or reemerging fungi, or lead to the rapid development of the resistance. This review will focus on the pathogenic yeast Candida albicans, since a large body of work on the factors and mechanism associated with antifungal drug resistance in this organism is reported sufficiently. It will certainly elaborate the probable molecular targets for drug design, discovered to date.
RESUMEN
The lectin isolated from mature seeds of Cicer arietinum (CAL) agglutinates pronase-treated rabbit and human erythrocytes and its haemagglutination activity is inhibited by fetuin and desialated fetuin but not by simple monosaccharides or oligosaccharides. The purified lectin is a dimer of molecular weight 43,000 Da composed of two identical subunits (MW 21,500), as confirmed by SDS-PAGE. The lectin has been crystallized using the hanging-drop vapour-diffusion method at 295 K over a well solution containing 0.2 M sodium acetate, 0.1 M sodium phosphate buffer pH 6.5 and 14%(w/v) polyethylene glycol 8000. The triangular prism-shaped crystals belong to space group R3 and have unit-cell parameters a = b = 81.2, c = 69.4 A. The diffraction data are 93.8% complete to 2.3 A Bragg spacing with an Rmerge of 0.103.
Asunto(s)
Cicer/química , Lectinas de Plantas/química , Secuencia de Aminoácidos , Dicroismo Circular , Secuencia Conservada , Cristalización , Datos de Secuencia Molecular , Lectinas de Plantas/aislamiento & purificación , Conformación Proteica , Estructura Secundaria de Proteína , Subunidades de Proteína/química , Subunidades de Proteína/aislamiento & purificación , Semillas/química , Alineación de Secuencia , Homología de Secuencia de Aminoácido , Difracción de Rayos XRESUMEN
This study was carried out to see the hepatobiliary clearance of 99m Tc-Mebrofenin radiopharmaceutical in D-galactosamine induced hepatic rats. Furthermore, protective effect of turmeric extract has been studied in these hepatitis rats. Hepatitis was induced with intraperitoneal injection of D-galactosamine (400 mg/kg b. wt) in these rats. 1% turmeric extract was given along with their normal diet for 15 days. Turmeric extract treatment significantly increased the hepatic uptake of radioactivity and accelerated the excretion of 99m Tc-Mebrofenin as compared to control rats. (P < 0.001). In D-galactosamine administered rats, a significant delay was observed in 99m Tc-Mebrofenin excretion as compared to controls. However, D-galactosamine administered rats, pretreated with turmeric extract or concurrently treated with turmeric extract showed a near normal pattern of 99m Tc-Mebrofenin excretion. Hence, it can be suggested that turmeric extract may improve the liver function by detoxification.
Asunto(s)
Bilis/metabolismo , Enfermedad Hepática Inducida por Sustancias y Drogas/metabolismo , Enfermedad Hepática Inducida por Sustancias y Drogas/prevención & control , Curcuma/química , Galactosamina , Iminoácidos , Hígado/metabolismo , Compuestos de Organotecnecio , Fitoterapia , Radiofármacos , Alanina Transaminasa/sangre , Fosfatasa Alcalina/metabolismo , Compuestos de Anilina , Animales , Aspartato Aminotransferasas/sangre , Glicina , Iminoácidos/farmacocinética , Inyecciones Intravenosas , Hígado/enzimología , Pruebas de Función Hepática , Masculino , Compuestos de Organotecnecio/farmacocinética , Raíces de Plantas/química , Radiofármacos/farmacocinética , Ratas , Ratas Wistar , Distribución TisularRESUMEN
Proteinase-activated receptor-2 (PAR-2) is a member of a family of G-protein-coupled, seven-transmembrane domain receptors that are activated by proteolytic cleavage. The receptor is expressed in a number of different tissues and potential physiological activators identified thus far include trypsin and mast cell tryptase. Acrosin, a trypsin-like serine proteinase found in spermatozoa of all mammals, was found to cleave a model peptide fluorescent quenched substrate representing the cleavage site of PAR-2. This substrate was cleaved with kinetics similar to those of the known PAR-2 activators, trypsin and mast cell tryptase. Acrosin was also shown to induce significant intracellular calcium responses in Chinese hamster ovary cells stably expressing intact human PAR-2, most probably due to activation of the receptor. Immunohistochemical studies using PAR-2 specific antibodies indicated that the receptor is expressed by mouse oocytes, which suggests that acrosin may play additional role(s) in the fertilization process via the activation of PAR-2 on oocytes.
Asunto(s)
Acrosina/metabolismo , Calcio/metabolismo , Oocitos/fisiología , Receptores de Trombina/fisiología , Espermatozoides/enzimología , Animales , Células CHO , Cricetinae , Femenino , Humanos , Cinética , Masculino , Ratones , Receptor PAR-2 , Receptores de Trombina/genética , Proteínas Recombinantes/metabolismo , Transfección , Tripsina/metabolismoRESUMEN
Relaxin is a reproductive hormone that has historically been characterized as being responsible for pubic ligament loosening and cervical ripening. Recently, relaxin has been associated with neovascularization of the endometrial lining of the uterus, potentially via specific induction of vascular endothelial growth factor. Previously conducted clinical studies using partially purified porcine relaxin have described relaxin's ability to stimulate the healing of ischemic wounds, suggesting that relaxin may also have angiogenic effects at sites of ischemic wound healing. In the present study, relaxin's angiogenic effects in the context of wound repair were tested in rodent models of angiogenesis and wound healing. Relaxin showed an ability to stimulate new blood vessel formation, particularly at ischemic wound sites, and to induce both vascular endothelial growth factor and basic fibroblast growth factor specifically in cells, presumably including macrophages, collected from wound sites. Resident macrophages collected from nonwound sites, such as the lung, did not show altered expression of these cytokines following relaxin administration. Because angiogenic wound cells are frequently macrophages, THP-1 cells, a cell line of monocyte lineage that binds relaxin specifically, were tested for and shown to induce vascular endothelial growth factor and basic fibroblast growth factor in response to relaxin. In conclusion, relaxin may be useful in the treatment of ischemic wounds by stimulating angiogenesis via the induction of vascular endothelial growth factor and basic fibroblast growth factor in wound macrophages.
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Factores de Crecimiento Endotelial/metabolismo , Expresión Génica/efectos de los fármacos , Isquemia/tratamiento farmacológico , Linfocinas/efectos de los fármacos , Linfocinas/metabolismo , Neovascularización Fisiológica/efectos de los fármacos , Relaxina/farmacología , Cicatrización de Heridas/efectos de los fármacos , Heridas y Lesiones/tratamiento farmacológico , Animales , Línea Celular , Citocinas/efectos de los fármacos , Citocinas/genética , Citocinas/metabolismo , Modelos Animales de Enfermedad , Evaluación Preclínica de Medicamentos , Factores de Crecimiento Endotelial/genética , Factor 2 de Crecimiento de Fibroblastos/efectos de los fármacos , Factor 2 de Crecimiento de Fibroblastos/genética , Factor 2 de Crecimiento de Fibroblastos/metabolismo , Isquemia/complicaciones , Linfocinas/genética , Macrófagos/efectos de los fármacos , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Transcripción Genética , Factor A de Crecimiento Endotelial Vascular , Factores de Crecimiento Endotelial Vascular , Heridas y Lesiones/complicacionesRESUMEN
A role for glycoprotein (GP)V in platelet function has been proposed on the basis of observations that GP V is the major thrombin substrate on intact platelets cleaved during thrombin-induced platelet aggregation, and that GP V promotes GP Ib-IX surface expression in heterologous cells. We tested the hypotheses that GP V is involved in thrombin-induced platelet activation, in GP Ib-IX expression, and in other platelet responses by generating GP V null mice. Contrary to expectations, GP V -/- platelets were normal in size and expressed normal amounts of GP Ib-IX that was functional in von Willebrand factor binding, explaining why defects in GP V have not been observed in Bernard-Soulier syndrome, a bleeding disorder caused by a lack of functional GP Ib-IX-V. Moreover, in vitro analysis demonstrated that GP V -/- platelets were hyperresponsive to thrombin, resulting in increased fibrinogen binding and an increased aggregation response. Consistent with these findings, GP V -/- mice had a shorter bleeding time. These data support a role for GP V as a negative modulator of platelet activation. Furthermore, they suggest a new mechanism by which thrombin enhances platelet responsiveness independent of activation of the classical G-protein-coupled thrombin receptors.
Asunto(s)
Plaquetas/fisiología , Glicoproteínas de Membrana Plaquetaria/genética , Trombina/fisiología , Animales , Tiempo de Sangría , Eliminación de Gen , Ratones , Ratones Noqueados , Datos de Secuencia Molecular , Glicoproteínas de Membrana Plaquetaria/química , Glicoproteínas de Membrana Plaquetaria/fisiologíaRESUMEN
A human sequence IgGkappa anti-CD4 monoclonal antibody (mAb), HM6G, originally isolated from a human immunoglobulin transgenic mouse was specific for and bound with high binding avidity to the CD4 antigen expressed on human, chimpanzee, and cynomolgus monkey T cells. Prior to testing this mAb in human clinical trials, a number of preclinical primate studies were performed. In chimpanzees, HM6G did not deplete circulating CD4(+) T cells and was cleared in a dose-dependent manner. In contrast, this mAb administered to cynomolgus monkeys depleted CD4(+) T cells (albeit only at high doses) and its clearance, which had reached saturation even at very low doses, was much slower. These differences were most likely due to the additional and rather substantial expression of the CD4 antigen on chimpanzee monocytes. In monkeys, the T cell depletion was mitigated by infusing the mAb over 30 min or longer (as opposed to 30 s) while only slightly altering the clearance. As expected, the human mAb did not induce an immune response in chimpanzees, although it did induce a low titer response in monkeys. These disparate pharmacokinetic and pharmacodynamic results suggest prudence when extrapolating results obtained in nonhuman models to humans.
Asunto(s)
Anticuerpos Monoclonales/inmunología , Antígenos CD4/inmunología , Macaca fascicularis/inmunología , Pan troglodytes/inmunología , Animales , Anticuerpos Monoclonales/administración & dosificación , Linfocitos T CD4-Positivos/inmunología , Células CHO , Recuento de Células , Cricetinae , Humanos , Cinética , Ratones , PrimatesRESUMEN
The protective effect of tumeric extract (TE) in diet on CCl4-treated rats was studied. Rats were divided into 5 groups: (1) untreated, (2) CCl4 treated, (3) pre-TE for 2 weeks followed by CCl4, (4) TE + CCl4 given concurrently and (5) 5% TE as positive control. The serum levels of bilirubin, cholesterol, aspartate aminotransferase, (AST), alanine amino transferase (AST), (ALT) and alkaline phosphatase were estimated after 1, 2 and 3 months. CCl4 caused a maximum increase (2-3-fold in all the above parameters. As compared to CCl4 group, a short pre-treatment of TE showed reduction in cholesterol, bilirubin, AST, ALT and alkaline phosphatase activity whereas concurrent treatment of TE + CCl4 reduced to a greater extent the levels of all parameters except ALT. To conclude, concurrent treatment of TE gave significant protection against CCl4 though the values did not reach the normal levels.
Asunto(s)
Intoxicación por Tetracloruro de Carbono/terapia , Enfermedad Hepática Inducida por Sustancias y Drogas/terapia , Extractos Vegetales , Animales , Bilirrubina/sangre , Enfermedad Hepática Inducida por Sustancias y Drogas/sangre , Enfermedad Hepática Inducida por Sustancias y Drogas/enzimología , Curcuma , Masculino , Ratas , Ratas WistarRESUMEN
A normocalcemic animal model of vitamin D (vit. D)-deficiency has been successfully developed by feeding a high calcium (Ca2+) diet to vit. D.-deficient rats. The modulating role of Ca2+ on the hepatic antioxidant defence system and lipid peroxidation has been evaluated in this model. Partial restoration of liver function was noted in these rats following extra Ca2+ feeding. Serum alkaline phosphatase and alanine aminotransferase reverted to a normal level. The reduced levels of hepatic SOD and glutathione peroxidase in vit. D.-deficient rats, were also increased after extra Ca2+ supplementation. Even elevated lipid peroxidation due to vit. D.-deficiency was reduced after feeding the extra Ca(2+)-supplemented diet. However, catalase activity remained at the control level throughout the study. The results provide important evidence that normocalcemia is essential for maintaining the hepatic antioxidant defence and controlling lipid peroxidation in the in vivo milieu.
Asunto(s)
Calcio/metabolismo , Peroxidación de Lípido , Hígado/metabolismo , Deficiencia de Vitamina D/metabolismo , Fosfatasa Alcalina/sangre , Animales , Calcio de la Dieta/administración & dosificación , Modelos Animales de Enfermedad , Glutatión Peroxidasa/metabolismo , Hígado/enzimología , Masculino , Ratas , Ratas Wistar , Superóxido Dismutasa/metabolismo , Transaminasas/sangreRESUMEN
Serum ferritin, one of the nonspecific tumor markers, was studied in 102 thyroid cancer patients, who had been thyroidectomized and were off thyroxine for 1 month, making them hypothyroid. Serum ferritin in thyroid cancer patients was not significantly different as compared to controls. Nevertheless, high levels of serum ferritin were observed in the thyroid cancer group as compared to primary hypothyroid patients. Furthermore, there was a significant difference in serum ferritin between thyroid cancer patients without metastasis and those with metastasis, patients with metastasis showing higher levels. Classification of thyroid cancer patients into different histological types revealed higher ferritin levels in follicular carcinoma as compared to papillary carcinoma. These data suggest that, although serum ferritin may not be a tumor marker for thyroid cancer, this parameter seems to be sensitive to the presence of metastasis and the histologic diagnosis.
Asunto(s)
Biomarcadores de Tumor/sangre , Ferritinas/sangre , Neoplasias de la Tiroides/sangre , Adenocarcinoma Folicular/sangre , Adulto , Carcinoma Papilar/sangre , Femenino , Humanos , Masculino , Persona de Mediana Edad , Metástasis de la Neoplasia , Valores de ReferenciaRESUMEN
Rats were made hypo and 'hyperthyroid' with propylthiouracil (PTU) and L-Thyroxine (L-T) respectively. The hypo and hyperthyroid status in these rats were confirmed by serum level of T4 and T3. Liver iron was significantly increased in both the hypo and hyperthyroid animals. However, liver ferritin synthesis rate was reduced by 36% in hypothyroid rats, and elevated by 38% in hyperthyroid ones. A similar trend was seen in liver ferritin concentration. Further, serum transaminases were elevated only in animals of the hyperthyroid group. It appears from the present data that ferritin metabolism is influenced by thyroid hormone as well as by iron. Thus, the raised serum ferritin in hyperthyroid patients may be partially attributed to increased ferritin synthesis in the liver and its possible leakage into circulation.
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Ferritinas/metabolismo , Glándula Tiroides/fisiología , Albúminas/biosíntesis , Animales , Ferritinas/biosíntesis , Hipertiroidismo/inducido químicamente , Hipertiroidismo/metabolismo , Hipotiroidismo/inducido químicamente , Hipotiroidismo/metabolismo , Hierro/sangre , Hierro/metabolismo , Cinética , Hígado/enzimología , Hígado/metabolismo , Masculino , Propiltiouracilo , Ratas , Ratas Wistar , Hormonas Tiroideas/fisiología , Tiroxina/sangre , Triyodotironina/sangreRESUMEN
Ricin, a highly toxic protein from castor beans was administered (ip) to rats in a dose of 1.25 micrograms/100 g to selectively deplete at least 60-70% of Kupffer cells. This dose spared hepatocytes. This rat model was used to study acute phase protein synthesis and the role of Kupffer cells in acute phase response (APR). Ricin itself induced an APR, similar in pattern but of lower magnitude, than that induced by turpentine. However, the effect of combination of ricin and turpentine on APR was not additive. Kupffer cells appear to play permissive role in APR through mediators like hepatocytes stimulating factors.
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Proteínas de Fase Aguda/biosíntesis , Reacción de Fase Aguda/metabolismo , Macrófagos del Hígado/fisiología , Ricina/farmacología , Proteínas de Fase Aguda/efectos de los fármacos , Animales , Modelos Animales de Enfermedad , RatasRESUMEN
The effects of Plasmodium berghei infection on liver function and plasma orosomucoid metabolism were investigated in Wistar rats. Infected rats with 20-25% parasitaemia manifested increased serum transaminase levels, hypoalbuminaemia and hypoproteinaemia. In spite of such indications of deranged liver function, the hepatic synthesis rate (as measured by 14C-amino acid incorporation) of seromucoids predominantly orosomucoid or alpha 1-acid glycoprotein) was increased by 73%. The circulating levels of this glycoprotein were also doubled in infected animals. The albumin synthesis rate was not increased. This preferential synthesis and increase in circulating levels of orosomucoid may have in vivo significance in malarial infection, in view of reports that orosomuocid has influence on in vitro invasion of red cells by malarial parasites.
Asunto(s)
Malaria/metabolismo , Orosomucoide/biosíntesis , Plasmodium berghei , Animales , Hígado/metabolismo , Malaria/etiología , Masculino , Ratas , Ratas EndogámicasRESUMEN
Rats were rendered vitamin D-deficient by housing them in a room free of ultraviolet light and maintaining them for 20 weeks on a diet devoid of only vitamin D. The vitamin D-deficiency state was confirmed by the undetectable levels of circulating vitamin D metabolites, severe hypocalcaemia and significantly reduced intestinal calcium transport. Liver function and protein metabolism in these rats were assessed by bromosulphthalein (BSP) clearance, liver histology, plasma transaminases and alkaline phosphatase, and 14C-labelled amino acid incorporation into liver and plasma proteins. Subtle alterations in hepatic function, as manifested by delayed BSP clearance, elevated levels of plasma transaminases and alkaline phosphatase, were noticed. Liver histology revealed changes consistent with periportal necrosis. Synthesis of liver and plasma proteins were reduced by 26-34% (P less than 0.01), without affecting the circulating levels of plasma proteins, suggesting reduced protein turnover in vitamin D-deprived rats. The results strongly suggest the direct/indirect involvement of vitamin D in mediating the altered liver function.
Asunto(s)
Hígado/fisiopatología , Deficiencia de Vitamina D/fisiopatología , Animales , Proteínas Sanguíneas/metabolismo , Masculino , Ratas , Ratas Endogámicas , Vitamina D/metabolismoRESUMEN
Rodent model of filariasis was developed by infecting Wistar rats with Litomosoides carinii. Liver function tests, plasma protein concentrations, and synthesis rates of liver-formed proteins were estimated in these rats at 63 and 90 days post-infection. At 63 days post-infection, aspartate aminotransferase and alkaline phosphatase were significantly increased. Alanine aminotransferase, plasma total proteins and plasma albumin were in the normal range. However, at 90 days post-infection all these parameters were affected, reflecting progressive liver involvement. Hypoalbuminemia at 90 days post-infection did not appear to be due to decreased synthesis rate, indicating higher catabolism and/or altered distribution in pools.
Asunto(s)
Proteínas Sanguíneas/metabolismo , Filariasis/fisiopatología , Parasitosis Hepáticas/fisiopatología , Hígado/fisiopatología , Animales , Arvicolinae , Masculino , Ratas , Ratas EndogámicasRESUMEN
In rats a single injection (330 mg/kg) of D-galactosamine significantly inhibited in vivo incorporation of 14C-amino acids into fibrinogen, seromucoids and total liver proteins, but not albumin, by one third. Prior chronic exposure to ethanol (5 g/kg/day for 6 weeks) potentiated the inhibition of synthesis of all protein fractions (including albumin) up to about 50%. Propylthiouracil had no beneficial but deleterious effect against this potentiation of hepatotoxicity.