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1.
J Phys Chem Lett ; 15(21): 5586-5593, 2024 May 30.
Artículo en Inglés | MEDLINE | ID: mdl-38754086

RESUMEN

Herein, MoS2 quantum dots (QDs) with controlled optical, structural, and electronic properties are synthesized using the femtosecond pulsed laser ablation in liquid (fs-PLAL) technique by varying the pulse width, ablation power, and ablation time to harness the potential for next-generation optoelectronics and quantum technology. Furthermore, this work elucidates key aspects of the mechanisms underlying the near-UV and blue emissions the accompanying large Stokes shift, and the consequent change in sample color with laser exposure parameters pertaining to MoS2 QDs. Through spectroscopic analysis, including UV-visible absorption, photoluminescence, and Raman spectroscopy, we successfully unraveled the mechanisms for the change in optoelectronic properties of MoS2 QDs with laser parameters. We realize that the occurrence of a secondary phase, specifically MoO3-x, is responsible for the significant Stokes shift and blue emission observed in this QD system. The primary factor influencing these activities is the electron transfer observed between these two phases, as validated by excitation-dependent photoluminescence and XPS and Raman spectroscopies.

2.
Phys Rev E ; 104(5-1): 054217, 2021 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-34942841

RESUMEN

The classical surrogate data tests, which are used to differentiate linear noise processes from nonlinear processes, are not suitable for nonstationary time series. In this paper, we propose a surrogate data test that can be applied on both stationary time series as well as nonstationary time series with short-term fluctuations. The method is based on the idea of constructing a network from the time series, employing a generalized symbolic dynamics method introduced in this work, and using any one of the several easily computable network parameters as discriminating statistics. The construction of the network is designed to remove the long-term trends in the data automatically. The network-based test statistics pick up only the short-term variations, unlike the discriminating statistics of the traditional methods, which are influenced by nonstationary trends in the data. The method is tested on several systems generated by linear or nonlinear processes and with deterministic or stochastic trends, and in all cases it is found to be able to differentiate between linear stochastic processes and nonlinear processes quite accurately, especially in cases where the common methods would lead to false rejections of the null hypothesis due to nonstationarity being interpreted as nonlinearity. The method is also found to be robust to the presence of experimental or dynamical noise of a moderate level in an otherwise nonlinear system.

3.
Environ Technol ; 40(13): 1633-1643, 2019 May.
Artículo en Inglés | MEDLINE | ID: mdl-29347885

RESUMEN

Affordable clay-based ceramic filters with multifunctional properties were prepared using low-cost and active ingredients. The characterization results clearly revealed well crystallinity, structural elucidation, extensive porosity, higher surface area, higher stability, and durability which apparently enhance the treatment efficiency. The filtration rates of ceramic filter were evaluated under gravity and the results obtained were compared with a typical gravity slow sand filter (GSSF). All ceramic filters showed significant filtration rates of about 50-180 m/h, which is comparatively higher than the typical GSSF. Further, purification efficiency of clay-based ceramic filters was evaluated by considering important drinking water parameters and contaminants. A significant removal potential was achieved by the clay-based ceramic filter with 25% and 30% activated carbon along with active agents. Desired drinking water quality parameters were achieved by potential removal of nitrite (98.5%), nitrate (80.5%), total dissolved solids (62%), total hardness (55%), total organic pollutants (89%), and pathogenic microorganisms (100%) using ceramic filters within a short duration. The remarkable purification and disinfection efficiencies were attributed to the extensive porosity (0.202 cm3 g-1), surface area (124.61 m2 g-1), stability, and presence of active nanoparticles such as Cu, TiO2, and Ag within the porous matrix of the ceramic filter.


Asunto(s)
Agua Potable , Purificación del Agua , Cerámica , Arcilla , Filtración
4.
Chem Commun (Camb) ; 53(68): 9446-9449, 2017 Aug 22.
Artículo en Inglés | MEDLINE | ID: mdl-28795693

RESUMEN

A palladium-catalyzed aminocarbonylation of halo-substituted 7-azaindoles utilizing CHCl3 as the carbonyl source has been developed for the straightforward incorporation of an amide functional group. The protocol was extended to other heteroarenes such as pyrazolopyridines and indazoles. The substrate scope of the reaction with respect to heteroarenes and the amine component is reported. This method offers an alternative avenue for aminocarbonylation of pharmaceutically important heterocycles.

5.
Org Biomol Chem ; 15(26): 5457-5461, 2017 Jul 05.
Artículo en Inglés | MEDLINE | ID: mdl-28621792

RESUMEN

An efficient Ru(ii)-catalyzed site-selective C-H arylation of 2-pyridones and 1-isoquinolinones was achieved with boronic acids by using pyridine as a directing group. The developed protocol is general and provides rapid access to an array of C6-arylated 2-pyridones and C3-arylated 1-isoquinolinones in excellent yields. These designed arylated 2-pyridones and 1-isoquinolinones can serve as key structural motifs for accessing functionalized pyridines and isoquinolines.


Asunto(s)
Isoquinolinas/química , Piridonas/química , Rutenio/química , Catálisis , Estructura Molecular
6.
Eur J Med Chem ; 110: 1-12, 2016 Mar 03.
Artículo en Inglés | MEDLINE | ID: mdl-26807542

RESUMEN

N-aralkylpyroglutamides of substituted bispidine were prepared and evaluated for their ability to inhibit collagen induced platelet aggregation, both in vivo and in vitro. Some compounds showed high anti-platelet efficacy (in vitro) of which six inhibited both collagen as well as U46619 induced platelet aggregation with concentration dependent anti-platelet efficacy through dual mechanism. In particular, the compound 4j offered significant protection against collagen epinephrine induced pulmonary thromboembolism as well as ferric chloride induced arterial thrombosis, without affecting bleeding tendency in mice. Therefore, the present study suggests that the compound 4j displays a remarkable antithrombotic efficacy much better than aspirin and clopidogrel.


Asunto(s)
Plaquetas/efectos de los fármacos , Compuestos Bicíclicos Heterocíclicos con Puentes/uso terapéutico , Inhibidores de Agregación Plaquetaria/uso terapéutico , Embolia Pulmonar/prevención & control , Ácido Pirrolidona Carboxílico/uso terapéutico , Trombosis/prevención & control , Animales , Coagulación Sanguínea/efectos de los fármacos , Plaquetas/patología , Compuestos Bicíclicos Heterocíclicos con Puentes/efectos adversos , Compuestos Bicíclicos Heterocíclicos con Puentes/síntesis química , Compuestos Bicíclicos Heterocíclicos con Puentes/química , Hemorragia/inducido químicamente , Humanos , Ratones , Adhesividad Plaquetaria/efectos de los fármacos , Agregación Plaquetaria/efectos de los fármacos , Inhibidores de Agregación Plaquetaria/efectos adversos , Inhibidores de Agregación Plaquetaria/síntesis química , Inhibidores de Agregación Plaquetaria/química , Embolia Pulmonar/sangre , Embolia Pulmonar/patología , Ácido Pirrolidona Carboxílico/efectos adversos , Ácido Pirrolidona Carboxílico/síntesis química , Ácido Pirrolidona Carboxílico/química , Trombosis/sangre , Trombosis/patología
7.
Mitochondrial DNA A DNA Mapp Seq Anal ; 27(4): 2585-93, 2016 07.
Artículo en Inglés | MEDLINE | ID: mdl-26119113

RESUMEN

Genus Macrobrachium includes freshwater prawns which inhabit most diverse habitats ranging from low saline areas to inland hill streams and impounded water bodies. Being morphologically conserved, this genus has been exposed to severe disputes related to their taxonomy, systematics and phylogeny. Macrobrachium striatum and M. equidens represent two morphologically related congeneric species within this genus. Earlier, M. striatum was considered as a striped form of M. equidens. Though these species are now well-described morphologically and differentiated into two species, no molecular level investigation has been carried out in support of their speciation. We report a study on M. striatum and M. equidens with emphasis to their molecular data through mitochondrial markers (16S ribosomal RNA and cytochrome oxidase subunit I). Results obtained from developed molecular markers of the two species revealed considerable genetic differentiation between them. Phylogram generated using Minimum evolution and Neighbour joining analyses differentiated M. striatum and M. equidens as two independent species. Genetic distance data showed high interspecific divergence (ranging from 3.9% to 17.0% for 16S rRNA sequences and 13.8% to 21.0% for COI sequences) between M. striatum and M. equidens confirming the findings of phylogram. Hence, it could be delineated that M. striatum and M. equidens represent two distinct species within genus Macrobrachium with emphasis to their morphology and genetics.


Asunto(s)
Palaemonidae/genética , Animales , ADN Mitocondrial/genética , Ecosistema , Complejo IV de Transporte de Electrones/genética , Agua Dulce , Genoma Mitocondrial/genética , Palaemonidae/clasificación , Filogenia , ARN Ribosómico 16S/genética
8.
Rural Remote Health ; 15(3): 3405, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26390891

RESUMEN

INTRODUCTION: Documentation on prenatal intention for exclusive breastfeeding in rural India is scarce. The objective of this study was to examine exclusive breastfeeding intention and its predictors among rural pregnant women in Odisha state of India. METHODS: A cross-sectional survey was conducted involving 218 pregnant rural women in Odisha. A structured data collection tool was developed to measure knowledge, attitude, subjective norm, perceived control and intention for exclusive breastfeeding using continuous assessment scales. Bivariate and multivariate regression analysis was carried out. RESULTS: Only 29.8% of pregnant women reported a high intention for exclusive breastfeeding. Higher age (odds ratio (OR) 3.84, 95% confidence interval (CI) 1.48, 9.96), being literate (OR 1.46, 95% CI 1.06, 3.54), lower caste category (OR 6.85, 95% CI 1.88, 24.91) and receipt of breastfeeding education (OR 2.68, 95% CI 1.27, 5.65) had a significant relationship with exclusive breastfeeding intention. Breastfeeding education was positively associated with knowledge, attitude and subjective norm, but inversely related with perceived control (all p<0.05). High knowledge (OR 116.87, 95% CI 35.24, 387.56), positive attitude (OR 3.18, 95% CI 1.46, 6.62), supportive norm (OR 2.61, 95% CI 1.54, 4.77) and greater perceived control (OR 5.37, 95% CI 1.22, 16.61) among pregnant women had potential effects on their exclusive breastfeeding intention. CONCLUSIONS: The study implies that appropriate breastfeeding education sessions need to be tailor-made for prenatal stage to improve exclusive breastfeeding intention and practice in rural Odisha.


Asunto(s)
Lactancia Materna/psicología , Conocimientos, Actitudes y Práctica en Salud , Madres/psicología , Población Rural , Adolescente , Adulto , Factores de Edad , Lactancia Materna/estadística & datos numéricos , Estudios Transversales , Femenino , Humanos , India , Intención , Modelos Psicológicos , Madres/estadística & datos numéricos , Educación del Paciente como Asunto , Percepción , Embarazo , Factores Socioeconómicos , Adulto Joven
9.
Xenobiotica ; 45(6): 530-7, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25837690

RESUMEN

1. S007-867 is a novel antiplatelet agent that shows promising in vitro and in vivo efficacy. For further development and better pharmacological elucidation, we characterized pharmacokinetics and tissue distribution of S007-867 in a mouse model. 2. A sensitive, selective and robust LC-MS/MS method was developed and validated in the mouse plasma and tissue for quantification of S007-867. The chromatographic separation was performed on Waters Symmetry Shield C18 column (150 × 4.6 mm, 5 µm) using methanol and ammonium acetate buffer. 3. S007-867 was rapidly absorbed and distributed to various tissues. Following single oral administration of S007-867 in the mouse, the concentration was in the order of C intestine > C liver > C kidney > C heart > C spleen > C lungs > C brain. Tissue to plasma area under the plasma curve ratio suggested that the maximum amount of drug was found in the intestine and liver. Half life of S007-867 was found longer in the heart (8.08 h), spleen (∼ 7.94 h) and kidney (∼ 15.41 h) as compared with other tissues. 4. The preclinical pharmacokinetics and tissue distribution data obtained using this LC-MS/MS method are expected to assist the future clinical investigations of S007-867 as a promising antiplatelet agent.


Asunto(s)
Inhibidores de Agregación Plaquetaria/farmacología , Inhibidores de Agregación Plaquetaria/farmacocinética , Animales , Cromatografía Líquida de Alta Presión , Femenino , Masculino , Espectrometría de Masas , Ratones , Especificidad de Órganos/efectos de los fármacos
10.
Org Biomol Chem ; 13(5): 1481-91, 2015 Feb 07.
Artículo en Inglés | MEDLINE | ID: mdl-25474646

RESUMEN

Cu(II)-catalyzed cross-coupling of various aryl boronic acids with 5 and 6-amino indazoles has resulted in (arylamino)-indazoles. These (arylamino)-indazoles have been utilized in synthesizing medicinally important pyrazole-fused carbazoles via Pd(II)-catalyzed cross-dehydrogenative coupling (CDC). This combined N-arylation/C-H arylation strategy has been successfully applied to the regioselective synthesis of polyheterocycles 3,6-dihydropyrazolo[3,4-c]carbazoles and 1,6-dihydro pyrazolo[4,3-c]carbazoles. Quantum chemical analysis has been carried out to understand the regioselectivity and to trace the potential energy surface of the entire reaction upon 5-N-aryl-indazole conversion to the corresponding carbazole.


Asunto(s)
Carbazoles/química , Carbazoles/síntesis química , Cobre/química , Indazoles/química , Pirazoles/química , Catálisis , Técnicas de Química Sintética , Modelos Moleculares , Conformación Molecular , Estereoisomerismo , Especificidad por Sustrato
11.
J Renin Angiotensin Aldosterone Syst ; 16(4): 801-12, 2015 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-24496517

RESUMEN

INTRODUCTION: Various stress hormones are responsible for bringing out stress-related changes and are implicated in learning and memory processes. The extensive clinical experience of angiotensin receptor blockers (ARBs) and direct renin inhibitor as antihypertensive agents provides anecdotal evidence of improvements in cognition. The neurochemical basis underlying the anti-stress and nootropic effects are unclear. This study was aimed to determine the effects of aliskiren, valsartan and their combination on the neuromediators of the central nervous system (CNS) and periphery as well as on cognitive function. MATERIALS AND METHODS: Groups of rats were subjected to a forced swim stress for one hour after daily treatment with aliskiren, valsartan and their combination. The 24 h urinary excretion of vanillylmandellic acid (VMA), 5-hydroxyindoleacetic acid (5-HIAA), 6-ß-hydroxycortisol (6-ß-OH) cortisol and homovanillic acid (HVA) was determined in all groups under normal and stressed conditions. Nootropic activity was studied using cook's pole climbing apparatus and acetylcholinesterase (AChE) inhibitory activity by Ellman's method. RESULTS: Administration of aliskiren (10 mg/kg), valsartan (20 mg/kg) and their combination at a dose of 5 and 10 mg/kg respectively reduced the urinary metabolite levels. Further, all drugs showed significant improvement in scopolamine-impaired performance and produced inhibition of the AChE enzyme. CONCLUSIONS: The present study provides scientific support for the anti-stress and nootropic activities of aliskiren, valsartan and their combination.


Asunto(s)
Nootrópicos/farmacología , Sistema Renina-Angiotensina/efectos de los fármacos , Estrés Fisiológico/efectos de los fármacos , Acetilcolinesterasa/metabolismo , Amidas/farmacología , Animales , Reacción de Prevención/efectos de los fármacos , Encéfalo/efectos de los fármacos , Encéfalo/metabolismo , Femenino , Fumaratos/farmacología , Ácido Homovanílico/orina , Hidrocortisona/análogos & derivados , Hidrocortisona/orina , Ácido Hidroxiindolacético/orina , Metaboloma/efectos de los fármacos , Ratas Wistar , Valsartán/farmacología , Ácido Vanilmandélico/orina
12.
Eur J Med Chem ; 81: 456-72, 2014 Jun 23.
Artículo en Inglés | MEDLINE | ID: mdl-24859764

RESUMEN

A series of chiral lactam carboxamides of aminomethylpiperidine were synthesized and investigated for the collagen induced in vitro anti-platelet efficacy and collagen plus epinephrine induced in vivo pulmonary thromboembolism. The compound 31a (30 µM/kg) displayed a remarkable antithrombotic efficacy (60% protection) which was sustained for more than 24 h and points to its excellent bioavailability. The compounds 31a (IC50 = 6.6 µM) and 32a (IC50 = 37 µM), as well as their racemic mixture 28i (IC50 = 16 µM) significantly inhibited collagen-induced human platelet aggregation in vitro. Compound 34c displayed dual mechanism of action against both collagen (IC50 = 3.3 µM) and U46619 (IC50 = 2.7 µM) induced platelet aggregation. The pharmacokinetic study of 31a indicated very faster absorption, prolonged and constant systemic exposure and thereby exhibiting better therapeutic response.


Asunto(s)
Acetamidas/farmacología , Colágeno/antagonistas & inhibidores , Piperidinas/farmacología , Activación Plaquetaria/efectos de los fármacos , Inhibidores de Agregación Plaquetaria/farmacología , Acetamidas/administración & dosificación , Acetamidas/síntesis química , Animales , Coagulación Sanguínea/efectos de los fármacos , Pruebas de Coagulación Sanguínea , Colágeno/farmacología , Relación Dosis-Respuesta a Droga , Humanos , Ratones , Conformación Molecular , Piperidinas/administración & dosificación , Piperidinas/síntesis química , Inhibidores de Agregación Plaquetaria/administración & dosificación , Inhibidores de Agregación Plaquetaria/síntesis química , Relación Estructura-Actividad
13.
Inflamm Res ; 61(7): 707-18, 2012 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-22450700

RESUMEN

OBJECTIVE: 15(S)-Hydroxyeicosatetraenoic acid [15(S)-HETE] and 15(S)-hydroperoxyeicosatetraenoic acid [15(S)-HPETE] are the products of arachidonic acid formed in the 15-lipoxygenase pathway. They have opposing effects on the inflammatory process. The present study was designed to examine the role of these metabolites on angiogenesis, which is critically associated with inflammatory conditions. METHODS: Chick chorio-allantoic membrane (CAM), rat aortic rings and human umbilical vein endothelial cells (HUVECs) in culture were used to study the effect of 15(S)-HETE and 15(S)-HPETE on angiogenesis. Biochemical markers of angiogenesis were analysed by ELISA. RESULTS: 15(S)-HETE increased vessel density in chick CAM, induced sprouting in rat aortic rings and increased endothelial cell-cell contact and formation of tubular network-like structures in HUVECs. Furthermore, it up-regulated the expression of CD31, E-selectin and vascular endothelial growth factor (VEGF) in HUVECs, indicating its pro-angiogenic effect. 15(S)-HPETE, on the other hand, decreased vessel density in chick CAM, down-regulated the expression of E-selectin (<35 %), VEGF (<90 %) and CD31 (<50 %) and did not produce sprouting in aortic rings, suggesting an anti-angiogenic property. 15(S)-HETE-mediated up-regulation of CD 31 and VEGF was reversed by treatment with 15(S)-HPETE. CONCLUSION: These results indicate the divergent effects of hydroxy and hydroperoxy products of 15-LOX on angiogenesis, highlighting the role of these products in the co-dependence of inflammation and angiogenesis.


Asunto(s)
Ácidos Hidroxieicosatetraenoicos/farmacología , Leucotrienos/farmacología , Peróxidos Lipídicos/farmacología , Neovascularización Fisiológica/efectos de los fármacos , Animales , Aorta Torácica/efectos de los fármacos , Aorta Torácica/fisiología , Araquidonato 15-Lipooxigenasa/metabolismo , Células Cultivadas , Pollos , Membrana Corioalantoides/irrigación sanguínea , Membrana Corioalantoides/efectos de los fármacos , Células Endoteliales de la Vena Umbilical Humana/efectos de los fármacos , Células Endoteliales de la Vena Umbilical Humana/fisiología , Humanos , Técnicas In Vitro , Ratas , Ratas Sprague-Dawley
14.
J Orthop Case Rep ; 2(3): 28-30, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-27298870

RESUMEN

Cemented Bipolar arthroplasty is an established method for treatment of comminuted Intertrochanteric fractures. Reconstruction of greater trochanter is an essential technical step to avoid complications like abductor lurch gait. We here describe a technique of reconstruction and fixation of greater trochanter using cancellous screws with wide washers made of reconstruction plate and tension band wiring. This gives a stable fixation of greater trochanter and avoids cut out, slippage of implants.

15.
Results Pharma Sci ; 2: 1-8, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-25755988

RESUMEN

INTRODUCTION: Dissolution is the amount of substance that goes into solution per unit time under standardised conditions of liquid/solid interface, solvent composition and temperature. Dissolution is one of the most important tools to predict the in-vivo bioavailability and in some cases to determine bioequivalence and assure interchangeability. AIM: To compare the differences in dissolution behaviour of solid dosage forms between innovators (reference products) and their generic counterparts (tested products). METHODS: Four replicates for each batch of 37 tested medicines was carried out using A PT-DT70 dissolution tester from Pharma Test. A total of 13 branded medicines and 24 generic counterparts were obtained locally and internationally to detect any differences in their dissolution behaviour. They were tested according to the British Pharmacopeia, European Pharmacopeia and the US Pharmacopeia with the rate of dissolution determined by ultra-violet Spectrophotometery. RESULTS: Most tested medicines complied with the pharmacopoeial specifications and achieved 85% dissolution in 60 min. However, some generic medicines showed significant differences in dissolution rate at 60 and 120 min. Many generic medicines showed a slower dissolution rate than their branded counterparts such as the generic forms of omeprazole 20 mg. Some showed an incomplete dissolution such as the generic form of nifedipine 10 mg. Other generics showed faster dissolution rate than their branded counterpart such as the generic forms of meloxicam 15 mg. Moreover, some generics from different batches of the same manufacturer showed significant differences in their dissolution rate such as the generic forms of meloxicam 7.5 mg. Nevertheless, some generic medicines violated the EMA and the FDA guidelines for industry when they failed to achieve 85% dissolution at 60 min, such as the generic form of diclofenac sodium 50 mg. CONCLUSION: Most medicines in this study complied with the pharmacopeial limits. However, some generics dissolved differently than their branded counterparts. This can clearly question the interchangeability between the branded and its generic counterpart or even among generics.

16.
J Ethnopharmacol ; 134(1): 198-201, 2011 Mar 08.
Artículo en Inglés | MEDLINE | ID: mdl-21129469

RESUMEN

ETHNOPHARMACOLOGICAL RELEVANCE: Glycosmis arborea Roxb, syn. Glycosmis pentaphylla Retz, (Rutacea) is a shrub found all over India, have been used for the healing of wounds of livestock in Indian folk medicine. AIM OF THE STUDY: The present study provides a scientific evaluation for the wound healing potential of ethanolic extract of Glycosmis arborea leaves. METHODS AND MATERIALS: Excision and incision wounds were inflicted upon four groups containing six rats each. Group-1 was assigned as control (ointment base), Group-2 and Group-3 were treated with 5 and 10% EtOH extract ointment. Group-4 was treated with standard Nitrofurazone (0.2%) ointment. The parameters observed were percentage of wound contraction, epithelization period, tensile strength, hydroxyproline content. Ethanolic extract of Glycosmis arborea leaves was given orally at a dose of 200, 400mg/kg/day in dead space wound model. RESULTS: Topical application of Glycosmis arborea ointment (10%) in excision wound model significantly (P<0.05) increased the percentage of wound contraction (96.91%) compared with control (60.27%) and decreased the epithelization time. The tensile strength significantly (P<0.05) increased in Group-3 at 560.33 ± 6.48g when compared to control at 319.17±6.16 g. Rats treated with Glycosmis arborea extract (400mg/kg) showed significant (P<0.05) increase in hydroxyproline content at 54.94 ± 0.96 mg/g when compared with control at 30.77±1.13 mg/g. CONCLUSION: The ethanolic extract of Glycosmis arborea facilitated wound healing significantly, corroborating the folk medicinal use of this plant.


Asunto(s)
Extractos Vegetales/farmacología , Hojas de la Planta/química , Rutaceae/química , Cicatrización de Heridas/efectos de los fármacos , Animales , Ratas
17.
Artículo en Inglés | MEDLINE | ID: mdl-16859979

RESUMEN

A new water-soluble fluorescent fluoride ion signaling system has been developed based on the ligand exchange mechanism in aqueous medium. This procedure is based on the exchange of two Alizarin Red S (ARS) molecules coordinated to Al(III) by fluoride ion without interference from other common anions. The binary complex of ARS with Al(III) provides a sensitive signaling system for fluoride ion in the concentration range from 5x10(-6) to 3x10(-4) M. The ligand exchange reaction of ARS-Al(III) complex with fluoride ion has been investigated by UV-vis and fluorescence spectroscopies combined with the AM1 semi-empirical quantum chemical calculations. The pale orange fluorescence (lambdamax=575 nm) exhibited by the complex upon excitation at 435 nm decreases in intensity with fluoride addition with a detection limit of 0.1 mg L-1.


Asunto(s)
Aluminio/química , Antraquinonas/química , Colorantes Fluorescentes/química , Fluoruros/química , Solubilidad , Espectrometría de Fluorescencia , Agua/química
18.
Br J Pharmacol ; 130(2): 351-8, 2000 May.
Artículo en Inglés | MEDLINE | ID: mdl-10807673

RESUMEN

Troglitazone lowers blood glucose levels in Type II diabetic patients. To evaluate the insulin sensitizing action of troglitazone on glycogen synthesis we have used dexamethasone-treated 3T3 adipocytes as an in vitro model. Differentiated 3T3 adipocytes were incubated with 100 nM dexamethasone for 6 days. Troglitazone (1.0 microM) or metformin (1.0 mM) with or without 200 nM insulin was added during the last 4 days. At the end, insulin (100 nM) stimulated glycogen synthesis was determined using (14)C-glucose. Dexamethasone caused a 50% reduction in glycogen synthesis. Troglitazone caused an approximately 3 fold increase in glycogen synthesis from 43.9+/-3.4 to 120+/-16.2 nmols h(-1). Under identical conditions metformin had no significant effect. When cells were incubated with troglitazone and dexamethasone simultaneously for 6 days, troglitazone but not metformin completely prevented dexamethasone-induced insulin resistance. RU 486 (1.0 microM) also completely prevented the insulin resistance. Chronic incubation with dexamethasone and insulin resulted in a 73% reduction in glycogen synthesis. In these adipocytes, troglitazone was partially active with glycogen synthesis rising from 23.1+/-3.0 to 44.4+/-4.5 nmol h(-1), P<0.01 while metformin was inactive. Troglitazone stimulated 2-deoxyglucose uptake by 2 - 3 fold in dexamethasone-treated adipocytes. Metformin also increased glucose uptake significantly. Troglitazone did not affect insulin binding while a 2 fold increase was observed in normal adipocytes where it exhibited a modest effect. Since the effect of troglitazone was greater in dexamethasone-treated adipocytes, troglitazone is likely to act by preventing dexamethasone-induced alterations which may include (i) binding to glucocorticoid receptor and (ii) effect on glucose uptake. These data demonstrate the direct insulin sensitizing action of troglitazone on glycogen synthesis and suggest a pharmacological profile different from metformin.


Asunto(s)
Adipocitos/efectos de los fármacos , Cromanos/farmacología , Dexametasona/farmacología , Glucógeno/biosíntesis , Resistencia a la Insulina , Tiazoles/farmacología , Tiazolidinedionas , Células 3T3 , Abortivos Esteroideos/farmacología , Adipocitos/metabolismo , Animales , Sitios de Unión , Dexametasona/antagonistas & inhibidores , Relación Dosis-Respuesta a Droga , Interacciones Farmacológicas , Glucocorticoides/farmacología , Hipoglucemiantes/farmacología , Insulina/farmacología , Radioisótopos de Yodo , Ratones , Mifepristona/farmacología , Troglitazona
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