Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 10 de 10
Filtrar
Más filtros











Base de datos
Intervalo de año de publicación
1.
BMC Complement Altern Med ; 14: 107, 2014 Mar 20.
Artículo en Inglés | MEDLINE | ID: mdl-24650244

RESUMEN

BACKGROUND: Gastrodia elata Blume (GEB), commonly used medicinal herb, has been reported as a promising candidate for neurodegenerative diseases such as Parkinson's disease. The dopamine precursor, L-3,4-dihydroxyphenylalanine (L-DOPA), is the gold-standard drug for Parkinson's disease, but long-term treatment results in the L-dopa-induced dyskinesia (LID). This study was undertaken to examine the beneficial effects of GEB on L-DOPA induced dyskinesia in 6-hydroxydopamine (6-OHDA)-induced experimental Parkinsonism. METHODS: We tested the effects of GEB on LID in 6-hydroxydopamine hydrochloride-hemiparkinsonian mice. To analyze the dyskinetic anomalies, we measured abnormal involuntary movement (AIM). Immunohistological analyses of pERK and FosB expressions in the striatum are performed to explore the mechanism of GEB on LID. RESULTS: The finding of this study demonstrated that GEB (200, 400 and 800 mg/kg) alleviated L-dopa induced AIMs in a dose-dependent manner. In each integrative AIM subtype analysis, we also found that the GEB (400 and 800 mg/kg) treatment decreased L-DOPA-induced axial, limb, orolingual, and locomotive AIMs compared to the LID group. In addition, GEB normalized the abnormal LID-induced increase of pERK1/2 and FosB, the immediate early genes of LID in the striatum. CONCLUSIONS: In conclusion, our results provide a novel insight into the pharmacological actions of GEB that could have a benefit for PD patients through the reduction of LID.


Asunto(s)
Discinesia Inducida por Medicamentos/metabolismo , Gastrodia , Levodopa/efectos adversos , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Oxidopamina/efectos adversos , Enfermedad de Parkinson/tratamiento farmacológico , Proteínas Proto-Oncogénicas c-fos/metabolismo , Animales , Cuerpo Estriado/efectos de los fármacos , Cuerpo Estriado/metabolismo , Modelos Animales de Enfermedad , Dopamina/metabolismo , Discinesia Inducida por Medicamentos/tratamiento farmacológico , Levodopa/uso terapéutico , Masculino , Ratones Endogámicos C57BL , Enfermedad de Parkinson/metabolismo , Trastornos Parkinsonianos/tratamiento farmacológico , Trastornos Parkinsonianos/metabolismo , Fitoterapia , Extractos Vegetales/farmacología , Extractos Vegetales/uso terapéutico
2.
J Trauma Acute Care Surg ; 76(3): 771-8, 2014 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-24553547

RESUMEN

BACKGROUND: Generation of reactive oxygen species (ROS) is an important mechanism of ischemia-reperfusion injury. Abrupt reoxygenation compared with slow reoxygenation has been known to increase ROS generation. Thus, slow and stepwise reperfusion can reduce ROS generation and subsequent ischemia-reperfusion injury. This study investigated the effect of slow reperfusion by blood pressure-targeted stepwise resuscitation (PSR) in hemorrhagic shock. METHODS: Pressure-controlled hemorrhagic shock was induced in male Sprague-Dawley rats for 1 hour. Rats were then allocated to one of three groups (no-resuscitation group, n = 14; PSR group, n = 15; rapid normalization of blood pressure (RR) group, n = 15). Survival time and hemodynamic changes were recorded and compared. Blood samples and liver tissue were harvested after 6 hours of resuscitation in surviving rats. RESULTS: All of the rats in the no-resuscitation group were expired before the end of the 6-hour observation period. Survival times were significantly longer in the PSR group than in the RR group (survival rates, 11 of 15 vs. 5 of 15, log rank p = 0.032). Plasma amino alanine transferase, histologic liver injury, and ROS generation in the liver tissue were significantly lower in the PSR group than in the RR group (all findings significant, p < 0.05). In addition, PSR significantly decreased plasma nitric oxide, liver interleukin 1ß, and liver interleukin 6 compared with rapid resuscitation in addition to augmenting Akt survival pathways (all p < 0.05). CONCLUSION: Slow reperfusion by PSR decreased mortality, ROS generation, and liver injury in rats undergoing hemorrhagic shock. Stepwise resuscitation also decreased inflammatory cytokine production and augmented Akt survival pathways.


Asunto(s)
Presión Sanguínea/fisiología , Resucitación/métodos , Choque Hemorrágico/terapia , Alanina Transaminasa/sangre , Animales , Análisis de los Gases de la Sangre , Interleucina-1beta/análisis , Interleucina-6/análisis , Ácido Láctico/sangre , Hígado/química , Hígado/patología , Masculino , Óxido Nítrico/sangre , Ratas , Ratas Sprague-Dawley , Especies Reactivas de Oxígeno/análisis , Reperfusión/métodos , Choque Hemorrágico/patología , Choque Hemorrágico/fisiopatología
3.
J Pain ; 15(5): 535-49, 2014 May.
Artículo en Inglés | MEDLINE | ID: mdl-24524846

RESUMEN

UNLABELLED: Despite accumulating evidence of the clinical effectiveness of acupuncture, its mechanism remains largely unclear. We assume that molecular signaling around the acupuncture needled area is essential for initiating the effect of acupuncture. To determine possible bio-candidates involved in the mechanisms of acupuncture and investigate the role of such bio-candidates in the analgesic effects of acupuncture, we conducted 2 stepwise experiments. First, a genome-wide microarray of the isolated skin layer at the GB34-equivalent acupoint of C57BL/6 mice 1 hour after acupuncture found that a total of 236 genes had changed and that extracellular signal-regulated kinase (ERK) activation was the most prominent bio-candidate. Second, in mouse pain models using formalin and complete Freund adjuvant, we found that acupuncture attenuated the nociceptive behavior and the mechanical allodynia; these effects were blocked when ERK cascade was interrupted by the mitogen-activated protein kinase kinase (MEK)/mitogen-activated protein kinase (MAPK) inhibitor U0126 (.8 µg/µL). Based on these results, we suggest that ERK phosphorylation following acupuncture needling is a biochemical hallmark initiating the effect of acupuncture including analgesia. PERSPECTIVE: This article presents the novel evidence of the local molecular signaling in acupuncture analgesia by demonstrating that ERK activation in the skin layer contributes to the analgesic effect of acupuncture in a mouse pain model. This work improves our understanding of the scientific basis underlying acupuncture analgesia.


Asunto(s)
Analgesia por Acupuntura , Sistema de Señalización de MAP Quinasas/fisiología , Dolor/fisiopatología , Fenómenos Fisiológicos de la Piel , Animales , Western Blotting , Butadienos/farmacología , Modelos Animales de Enfermedad , Inhibidores Enzimáticos/farmacología , Quinasas MAP Reguladas por Señal Extracelular/antagonistas & inhibidores , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Formaldehído , Adyuvante de Freund , Expresión Génica , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Masculino , Ratones Endogámicos C57BL , Nitrilos/farmacología , Análisis de Secuencia por Matrices de Oligonucleótidos , Manejo del Dolor/métodos , Umbral del Dolor/efectos de los fármacos , Umbral del Dolor/fisiología , Fosforilación/fisiología , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Factores de Tiempo
4.
Brain Res ; 1544: 33-44, 2014 Jan 28.
Artículo en Inglés | MEDLINE | ID: mdl-24321617

RESUMEN

This study first showed the behavioural benefits of novel combination therapy of L-dopa with acupuncture on Parkinson's disease, and its underlying mechanisms within basal ganglia. The previous study reported that acupuncture may improve the motor function of a Parkinson's disease (PD) mouse model by increasing the dopamine efflux and turnover ratio of dopamine. Hence, we hypothesised that combining L-dopa with acupuncture would have a behavioural benefit for those with PD. We performed unilateral injections of 6-OHDA into the striatum of C57Bl/6 mice to model hemi-Parkinsonian attributes. To test motor function and dyskinetic anomalies, we examined cylinder behaviour and abnormal involuntary movement (AIM), respectively. We found that (1) a 50% reduced dose of L-dopa (7.5 mg/kg) combined with acupuncture showed an improvement in motor function that was comparable to mice given the standard dose of L-dopa treatment (15 mg/kg) only, and that (2) the combination treatment (L-dopa +acupuncture) was significantly superior in reducing AIM scores when equivalent doses of L-dopa were used. The combination treatment also significantly reduces the abnormal increase of GABA contents in the substantia nigra compared to the standard L-dopa treatment. Furthermore, abnormal expression of FosB, the immediate early gene of L-dopa induced dyskinesia (LID), was mitigated in the striatum by the combination treatment. All of these results indicate that acupuncture enhances the benefits of L-dopa on motor function with reduced dose of L-dopa and alleviating LID by normalising neurochemical imbalance within the basal ganglia.


Asunto(s)
Terapia por Acupuntura , Antiparkinsonianos/efectos adversos , Química Encefálica , Levodopa/efectos adversos , Enfermedad de Parkinson Secundaria/terapia , Animales , Terapia Combinada , Ácido Glutámico/análisis , Masculino , Ratones , Ratones Endogámicos C57BL , Movimiento/efectos de los fármacos , Oxidopamina/toxicidad , Enfermedad de Parkinson Secundaria/inducido químicamente , Proteínas Proto-Oncogénicas c-fos/efectos de los fármacos , Proteínas Proto-Oncogénicas c-fos/metabolismo , Sustancia Negra/química , Ácido gamma-Aminobutírico/análisis
5.
J Physiol Sci ; 62(5): 377-83, 2012 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-22773088

RESUMEN

The administration of kainic acid (KA) causes seizures and produces neurodegeneration in hippocampal CA3 pyramidal cells. The present study investigated a possible role of acupuncture in reducing hippocampal cell death and inflammatory events, using a mouse model of kainic acid-induced epilepsy. Male C57BL/6 mice received acupuncture treatments at acupoint HT8 or in the tail area bilaterally once a day for 2 days and again immediately after an intraperitoneal injection of KA (30 mg/kg). HT8 is located on the palmar surface of the forelimbs, between the fourth and fifth metacarpal bones. Twenty-four hours after the KA injection, neuronal cell survival, the activations of microglia and astrocytes, and mRNA expression of two proinflammatory cytokines, interleukin-1ß (IL-1ß) and tumor necrosis factor-α (TNF-α), were measured in the hippocampus. Acupuncture stimulation at HT8, but not in the tail area, significantly reduced the KA-induced seizure, neuron death, microglial and astrocyte activations, and IL-1ß mRNA expression in the hippocampus. The acupuncture stimulation also decreased the mRNA expression of TNF-α, but it was not significant. These results indicate that acupuncture at HT8 can inhibit hippocampal cell death and suppress KA-induced inflammatory events, suggesting a possible role for acupuncture in the treatment of epilepsy.


Asunto(s)
Terapia por Acupuntura/métodos , Encefalitis/terapia , Hipocampo/fisiología , Animales , Apoptosis , Citocinas/análisis , Modelos Animales de Enfermedad , Encefalitis/inducido químicamente , Encefalitis/patología , Agonistas de Aminoácidos Excitadores/farmacología , Hipocampo/química , Hipocampo/patología , Ácido Kaínico/farmacología , Masculino , Ratones , Ratones Endogámicos C57BL , Neuroglía/efectos de los fármacos , Neuroglía/patología , Neuronas/efectos de los fármacos , Neuronas/patología , Convulsiones/inducido químicamente , Convulsiones/patología , Convulsiones/terapia
6.
Brain Res ; 1429: 106-15, 2012 Jan 06.
Artículo en Inglés | MEDLINE | ID: mdl-22078207

RESUMEN

Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by progressive selective loss of dopaminergic neurons in the substantia nigra. Recently, bee venom was reported to protect dopaminergic neurons in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine induced mice PD model, however, the underlying mechanism is not fully understood. The objective of the present study is to investigate the neuroprotective mechanism of bee venom against Parkinsonian toxin, 1-methyl-4-phenylpyridine (MPP(+)), in SH-SY5Y human neuroblastoma cells. Our results revealed that bee venom pretreatment (1-100 ng/ml) increased the cell viability and decreased apoptosis assessed by DNA fragmentation and caspase-3 activity assays in MPP(+)-induced cytotoxicity in SH-SY5Y cells. Bee venom increased the anti-apoptotic Bcl-2 expression and decreased the pro-apoptotic Bax, cleaved PARP expressions. In addition, bee venom prevented the MPP(+)-induced suppression of Akt phosphorylation, and the neuroprotective effect of bee venom against MPP(+)-induced cytotoxicity was inhibited by a phosphatidylinositol 3-kinase (PI3K) inhibitor, LY294002. These results suggest that the anti-apoptotic effect of bee venom is mediated by the cell survival signaling, the PI3K/Akt pathway. These results provide new evidence for elucidating the mechanism of neuroprotection of bee venom against PD.


Asunto(s)
Apoptosis/efectos de los fármacos , Venenos de Abeja/farmacología , Neuronas/efectos de los fármacos , Fármacos Neuroprotectores/farmacología , Transducción de Señal/efectos de los fármacos , 1-Metil-4-fenilpiridinio/toxicidad , Western Blotting , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Fragmentación del ADN , Técnica del Anticuerpo Fluorescente , Humanos , Neuronas/metabolismo , Neuronas/patología , Fosfatidilinositol 3-Quinasas/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo
7.
PLoS One ; 6(11): e27566, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-22132113

RESUMEN

Parkinson's disease (PD) is caused by the selective loss of dopaminergic neurons in the substantia nigra (SN) and the depletion of striatal dopamine (DA). Acupuncture, as an alternative therapy for PD, has beneficial effects in both PD patients and PD animal models, although the underlying mechanisms therein remain uncertain. The present study investigated whether acupuncture treatment affected dopamine neurotransmission in a PD mouse model using 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). We found that acupuncture treatment at acupoint GB34 improved motor function with accompanying dopaminergic neuron protection against MPTP but did not restore striatal dopamine depletion. Instead, acupuncture treatment increased dopamine release that in turn, may lead to the enhancement of dopamine availability in the synaptic cleft. Moreover, acupuncture treatment mitigated MPTP-induced abnormal postsynaptic changes, suggesting that acupuncture treatment may increase postsynaptic dopamine neurotransmission and facilitate the normalization of basal ganglia activity. These results suggest that the acupuncture-induced enhancement of synaptic dopamine availability may play a critical role in motor function improvement against MPTP.


Asunto(s)
Terapia por Acupuntura , Dopamina/metabolismo , Actividad Motora/fisiología , Enfermedad de Parkinson/fisiopatología , Enfermedad de Parkinson/terapia , Sinapsis/metabolismo , 1-Metil-4-fenil-1,2,3,6-Tetrahidropiridina , Puntos de Acupuntura , Animales , Conducta Animal , Modelos Animales de Enfermedad , Fosfoproteína 32 Regulada por Dopamina y AMPc/metabolismo , Neuronas Dopaminérgicas/metabolismo , Neuronas Dopaminérgicas/patología , Masculino , Ratones , Ratones Endogámicos C57BL , Modelos Biológicos , Neostriado/patología , Neostriado/fisiopatología , Degeneración Nerviosa/complicaciones , Degeneración Nerviosa/patología , Degeneración Nerviosa/fisiopatología , Fosforilación , Proteínas Proto-Oncogénicas c-fos/metabolismo , Sinapsis/patología , Factores de Tiempo
8.
Int J Neurosci ; 121(10): 562-9, 2011 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-21770712

RESUMEN

It has been reported that acupuncture treatment reduced dopaminergic neuron degeneration in Parkinson's disease (PD) models. However, the mechanistic pathways underlying, such neuroprotection, are poorly understood. Here, we investigated the effects and the underlying mechanism of acupuncture in a mouse model of PD using 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). First, we observed that MPTP-induced impairment of Akt activation, but not MPTP-induced c-Jun activation, was effectively restored by acupuncture treatment in the substantia nigra. Furthermore, we demonstrated for the first time that the brain-specific blockade of phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway, by intranasal administration of LY294002, a specific inhibitor of PI3K/Akt signaling pathway, significantly blocked acupuncture-induced dopaminergic neuron protection and motor function improvement. Our results provide evidence that PI3K/Akt signaling pathway may play a central role in the mechanism underlying acupuncture-induced benefits in Parkinsonian mice.


Asunto(s)
Acupuntura , Neuronas Dopaminérgicas/fisiología , Intoxicación por MPTP , Actividad Motora/fisiología , Transducción de Señal/fisiología , Sustancia Negra/citología , Puntos de Acupuntura , Administración Intranasal , Animales , Cromonas/administración & dosificación , Modelos Animales de Enfermedad , Neuronas Dopaminérgicas/efectos de los fármacos , Inhibidores Enzimáticos/administración & dosificación , Regulación de la Expresión Génica/efectos de los fármacos , Regulación de la Expresión Génica/fisiología , Intoxicación por MPTP/metabolismo , Intoxicación por MPTP/patología , Intoxicación por MPTP/prevención & control , Masculino , Ratones , Ratones Endogámicos C57BL , Morfolinas/administración & dosificación , Actividad Motora/efectos de los fármacos , Fosfatidilinositol 3-Quinasas , Proteínas Proto-Oncogénicas c-jun/metabolismo , Prueba de Desempeño de Rotación con Aceleración Constante , Transducción de Señal/efectos de los fármacos , Sustancia Negra/efectos de los fármacos , Tirosina 3-Monooxigenasa/metabolismo
9.
J Ethnopharmacol ; 131(2): 433-42, 2010 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-20633628

RESUMEN

ETHNOPHARMACOLOGICAL RELEVANCE: A traditional herb, Yi-Gan San, has been widely used for the management of neurodegenerative disorders in traditional East Asian Medicine. AIM OF THE STUDY: The present study investigated the neuroprotective effects of Yi-Gan San in 1-methyl-4-phenylpyridine/1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced cytotoxicity in vitro and in vivo and sought to clarify its underlying mechanisms. MATERIALS AND METHODS: The effect of Yi-Gan San on 1-methyl-4-phenylpyridine was measured in terms of 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assays, caspase-3 activity, and western blot analysis of phosphorylated Akt, one of the survival-related signaling proteins in SH-SY5Y cells. The effects of Yi-Gan San were also confirmed in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced Parkinsonian mouse model using a rotarod test and tyrosine hydroxylase-immunohistochemistry. RESULTS: Pretreatment of Yi-Gan San with 1-methyl-4-phenylpyridine showed a significant protective effect on SH-SY5Y cells and significantly decreased the level of caspase-3 activity compared to the values for the 1-methyl-4-phenylpyridine-treated cells. This process increased the protein expressions of phosphorylated Akt, and an inhibitor of phosphatidylinositol 3-kinase (PI3K)/Akt, LY294002, significantly decreased this protective effect of Yi-Gan San. In the mouse Parkinson's disease model, treatment with Yi-Gan San also significantly improved motor functioning and prevented dopaminergic loss related to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine challenge. CONCLUSION: Using both in vitro and in vivo methods, this study revealed that Yi-Gan San has neuroprotective effects and rescues dopaminergic neurons from 1-methyl-4-phenylpyridine/1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine toxicity, possibly via the PI3K/Akt pathway.


Asunto(s)
Caspasa 3/metabolismo , Medicamentos Herbarios Chinos/uso terapéutico , Magnoliopsida , Neuronas/efectos de los fármacos , Fármacos Neuroprotectores/uso terapéutico , Enfermedad de Parkinson/tratamiento farmacológico , Fitoterapia , 1-Metil-4-fenil-1,2,3,6-Tetrahidropiridina/análogos & derivados , 1-Metil-4-fenilpiridinio , Animales , Línea Celular Tumoral , Cromonas/farmacología , Citotoxinas , Modelos Animales de Enfermedad , Dopamina/metabolismo , Medicamentos Herbarios Chinos/farmacología , Inhibidores Enzimáticos/farmacología , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Morfolinas/farmacología , Actividad Motora/efectos de los fármacos , Neuroblastoma/metabolismo , Neuronas/metabolismo , Fármacos Neuroprotectores/farmacología , Enfermedad de Parkinson/metabolismo , Fosforilación , Proteínas Proto-Oncogénicas c-akt/metabolismo
10.
Neurol Res ; 32 Suppl 1: 88-91, 2010 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-20034453

RESUMEN

OBJECTIVES: We explored the neuroprotective effects of bee venom acupuncture in acute 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced mouse model of Parkinson's disease. METHODS: Male C57BL/6 mice were divided into three groups: saline-injected control group, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-injected group and bee venom acupuncture-pretreated plus 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-injected group. Mice were injected with 0.02 ml bee venom (1 : 2000 w/v) to GB34 (Yangneungcheon) bilaterally once every 3 days for 2 weeks. After 2 weeks' pre-treatment, the mice were injected with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (20 mg/kg, i.p.) four times in 2 hour intervals. Tyrosine hydroxylase and phospho-Jun immunoreactivities in the substantia nigra and striatum were observed 3 days after 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine injection. RESULTS: Bee venom acupuncture prevented the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced loss of tyrosine hydroxylase immunoreactivity in the substantia nigra and striatum. Moreover, bee venom acupuncture attenuated 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced phospho-Jun immunoreactivity in the substantia nigra. DISCUSSION: We found that bee venom acupuncture effectively protected dopaminergic neurons against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine toxicity, possibly through inhibition of Jun activation. Our results suggest that bee venom acupuncture could be a potential preventive agent for Parkinson's disease.


Asunto(s)
Terapia por Acupuntura/métodos , Venenos de Abeja/uso terapéutico , Fármacos Neuroprotectores/uso terapéutico , Trastornos Parkinsonianos/tratamiento farmacológico , Trastornos Parkinsonianos/terapia , 1-Metil-4-fenil-1,2,3,6-Tetrahidropiridina , Enfermedad Aguda , Animales , Muerte Celular/efectos de los fármacos , Muerte Celular/fisiología , Cuerpo Estriado/efectos de los fármacos , Cuerpo Estriado/fisiopatología , Modelos Animales de Enfermedad , Proteínas Quinasas JNK Activadas por Mitógenos/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Neuronas/efectos de los fármacos , Neuronas/fisiología , Enfermedad de Parkinson , Trastornos Parkinsonianos/fisiopatología , Fosforilación , Sustancia Negra/efectos de los fármacos , Sustancia Negra/fisiopatología , Factores de Tiempo , Tirosina 3-Monooxigenasa/metabolismo
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA