RESUMO
Studies in our laboratory have characterized the putative neuromodulatory effects of a standardized extract of the green leaves of Ginkgo biloba (EGb), which comprises a formulation of 24% ginkgo-flavoglycosides and 6% ginkgo-terpenoid lactones, on conditioned suppression. This model comprises a suitable animal model for investigating the behavioral changes and pharmacological mechanisms that underlie fear memory and anxiety. The characterization of the effects on distinct stages of fear memory or fear extinction will help illustrate both the beneficial and harmful effects. Three hundred adult male Wistar rats were randomly assigned to 30 groups according to the treatment as follows: i-ii) control groups (CS-US and CSno-US); iii) vehicle group (12% Tween®80); and iv-vi) EGb groups (250, 500 and 1000mgkg(-1)); or experimental procedures designed to assess the effects of EGb treatment prior to the acquisition (n=20 per group) and retrieval of conditioned fear (n=10 per group) or prior to the extinction training (n=10 per group) and extinction retention test (n=10 per group). Furthermore, to better understand the effects of acute EGb treatment on fear memory, we conducted two additional analyses: the acquisition of within- and between-session extinction of fear memory (short- and long-term memory, respectively). No difference was identified between the control and treatment groups during the retention test (P>0.05), with the exception of the CSno-US group in relation to all groups (P<0.05). A between-session analysis indicated that EGb at 250mgkg(-1) facilitated the acquisition of extinction fear memory, which was verified by the suppression ration in the first trial of extinction training (SR=0.39) and the extinction retention test session (SR=0.53, P<0.05), without impairments in fear memory acquisition, which were evaluated during the retention test (SR=0.79). Moreover, EGb administered at 1000mgkg(-1) prior to conditioning did not enhance the long-term extinction memory, i.e., it did not prevent the return of extinguished fear memory in the extinction retention test, in which the spontaneous recovery of fear was demonstrated (SR=0.63, P<0.05); however, it significantly facilitated short-term memory as verified by data from the within-session extinction (1 to 8-10 trials) during the retention test (SR=0.73 to SR=0.59; P<0.05) and the extinction retention test (SR=0.63 to SR=0.41; P<0.05). Moreover, spontaneous recovery was identified in response to a higher dose of EGb when administered prior to extinction training (SR=0.75, P<0.05) and the extinction retention test (SR=0.70; P<0.05). At dose of 500mgkg(-1) EGb reduced the suppression ratio when administered prior to the retention test (SR=0.57) and extinction training (SR=0.55; P<0.05) without preventing the acquisition of fear memory, which suggests that EGb has anti-anxiety effects. Taken together, the current findings suggest that EGb differentially modulates short- and long-term memory, as well as anxiety-like behavior. The actions of EGb may provide information regarding the beneficial effects in the prevention and treatment of neurocognitive impairments and anxiety disorders. Additional analyses are necessary to facilitate an understanding of these effects; however, previous data from our group suggest that GABAergic, serotoninergic and glutamatergic receptors are potential targets of the effects of EGb on conditioned suppression.
Assuntos
Extinção Psicológica/efeitos dos fármacos , Ginkgo biloba , Memória de Longo Prazo/efeitos dos fármacos , Memória de Curto Prazo/efeitos dos fármacos , Extratos Vegetais/farmacologia , Psicotrópicos/farmacologia , Animais , Ansiedade/tratamento farmacológico , Condicionamento Psicológico/efeitos dos fármacos , Relação Dose-Resposta a Droga , Medo/efeitos dos fármacos , Masculino , Modelos Animais , Atividade Motora/efeitos dos fármacos , Distribuição Aleatória , Ratos Wistar , Fatores de TempoRESUMO
Our group previously demonstrated that short-term treatment with a standardized extract of Ginkgo biloba (EGb) changed fear-conditioned memory by modulating gene expression in the hippocampus, amygdaloid complex and prefrontal cortex. Although there are few controlled studies that support the long-term use of EGb for the prevention and/or treatment of memory impairment, the chronic use of Ginkgo is common. This study evaluated the effects of chronic treatment with EGb on the conditioned emotional response, assessed by the suppression of ongoing behavior and in the modulation of gene and protein expression. Male adult Wistar rats were treated over 28days and assigned to five groups (n=10) as follows: positive control (4mgkg(-1) Diazepam), negative control (12% Tween 80), EGb groups (0.5 and 1.0gkg(-1)) and the naïve group. The suppression of the licking response was calculated for each rat in six trials. Our results provide further evidence for the efficacy of EGb on memory. For the first time, we show that long-term treatment with the highest dose of EGb improves the fear memory and suggests that increased cAMP-responsive element-binding protein (CREB)-1 and glial fibrillary acidic protein (GFAP) mRNA and protein (P<0.001) in the dorsal hippocampus and amygdaloid complex and reduced growth and plasticity-associated protein 43 (GAP-43) (P<0.01) in the hippocampus are involved in this process. The fear memory/treatment-dependent changes observed in our study suggest that EGb might be effective for memory enhancement through its effect on the dorsal hippocampus and amygdaloid complex.
Assuntos
Tonsila do Cerebelo/fisiologia , Condicionamento Operante/efeitos dos fármacos , Ginkgo biloba/química , Hipocampo/fisiologia , Neuroglia/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Tonsila do Cerebelo/citologia , Tonsila do Cerebelo/efeitos dos fármacos , Animais , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/biossíntese , Interpretação Estatística de Dados , Diazepam/farmacologia , Medo/efeitos dos fármacos , Proteína GAP-43/biossíntese , Proteína Glial Fibrilar Ácida/biossíntese , Proteína Glial Fibrilar Ácida/genética , Hipocampo/citologia , Hipocampo/efeitos dos fármacos , Hipnóticos e Sedativos/farmacologia , Imuno-Histoquímica , Masculino , Memória/efeitos dos fármacos , Plasticidade Neuronal/efeitos dos fármacos , Extratos Vegetais/farmacologia , Córtex Pré-Frontal/efeitos dos fármacos , Córtex Pré-Frontal/metabolismo , Ratos , Ratos WistarRESUMO
An on-line preconcentration procedure using solid phase extraction (SPE) for the determination of copper in different water samples by inductively coupled plasma optical emission spectrometry (ICP-OES) is proposed. The copper was retained on a minicolumn filled with ethyl vinyl acetate (EVA) at pH 8.0 without using any complexing reagent. The experimental optimization step was performed using a two-level full factorial design. The results showed that pH, sample loading flow rate, and their interaction (at the tested levels) were statistically significant. In order to determine the best conditions for preconcentration and determination of copper, a final optimization of the significant factors was carried out using a central composite design (CCD). The calibration graph was linear with a regression coefficient of 0.995 at levels near the detection limit up to at least 300 µg L(-1). An enrichment factor (EF) of 54 with a preconcentration time of 187.5 s was obtained. The limit of detection (3σ) was 0.26 µg L(-1). The sampling frequency for the developed methodology was about 15 samples/h. The relative standard deviation (RSD) for six replicates containing 50 µg L(-1) of copper was 3.76%. The methodology was successfully applied to the determination of Cu in tap, mineral, river water samples, and in a certified VKI standard reference material.
Assuntos
Cobre/análise , Água Doce/análise , Extração em Fase Sólida/métodos , Calibragem , Limite de Detecção , Reprodutibilidade dos Testes , Extração em Fase Sólida/normasRESUMO
An on-line procedure for the determination of traces of total mercury in environmental and biological samples is described. The present methodology combines cold vapor generation associated to atomic absorption spectrometry (CV-AAS) with preconcentration of the analyte on a minicolumn packed with activated carbon. The retained analyte was quantitatively eluted from the minicolumn with nitric acid. After that, volatile specie of mercury was generated by merging the acidified sample and sodium tetrahydroborate(III) in a continuous flow system. The gaseous analyte was subsequently introduced via a stream of Ar carrier into the atomizer device. Optimizations of both, preconcentration and mercury volatile specie generation variables were carried out using two level full factorial design (2(3)) with 3 replicates of the central point. Considering a sample consumption of 25mL, an enrichment factor of 13-fold was obtained. The detection limit (3sigma) was 10ngL(-1) and the precision (relative standard deviation) was 3.1% (n=10) at the 5microgL(-1) level. The calibration curve using the preconcentration system for mercury was linear with a correlation coefficient of 0.9995 at levels near the detection limit up to at least 1000microgL(-1). Satisfactory results were obtained for the analysis of mercury in tap water and hair samples.
Assuntos
Poluentes Ambientais/análise , Mercúrio/análise , Carbono/química , Temperatura Baixa , Monitoramento Ambiental/instrumentação , Monitoramento Ambiental/métodos , Cabelo/química , Humanos , Sistemas On-Line , Espectrofotometria Atômica , Volatilização , Abastecimento de Água/análiseRESUMO
An on-line flow injection (FI) preconcentration-electrothermal atomic absorption spectrometry (ETAAS) method is developed for trace determination of chromium in drinking water samples by sorption on a conical minicolumn packed with activated carbon (AC) at pH 5.0. The chromium was removed from the minicolumn with 1.0% (v/v) nitric acid. An enrichment factor (EF) of 35-fold for a sample volume of 10ml was obtained. The detection limit (DL) value for the preconcentration method proposed was 3.0ngl(-1). The precision for 10 replicate determinations at the 0.5mugl(-1) Cr level was 4.0% relative standard deviation (R.S.D.), calculate with the peak heights obtained. The calibration graph using the preconcentration system for chromium was linear with a correlation coefficient of 0.9992 at levels near the detection limits up to at least 50mugl(-1). The method was successfully applied to the determination of Cr(III) and Cr(VI) in drinking water samples.
RESUMO
The present paper proposes an on-line preconcentration procedure for lead determination in Ilex paraguariensis (St. Hilaire) samples by ultrasonic nebulization associated to inductively coupled plasma optical emission spectrometry (USN-ICP-OES). It is based on the precipitation of lead(II) ion on a minicolumn packed with polyurethane foam using 2-(5-bromo-2-pyridilazo)-5-diethylaminophenol (5-Br-PADAP) as precipitating reagent. The collected analyte precipitate was quantitatively eluted from the minicolumn with 20% (v/v) nitric acid. An enhancement factor of 225-fold was obtained (15 for USN and 15 for preconcentration). The detection limit (DL) value for the preconcentration of 10.0 ml of sample was 40.0 ng/l. The relative standard deviation (R.S.D.) was 3.0% for a Pb concentration of 1 microg/l, calculated from the peak heights obtained. The calibration graph using the preconcentration system for lead was linear with a correlation coefficient of 0.9997, at levels near the detection limits up to at least 100 microg/l. The preconcentration procedure was successfully applied to the determination of lead in mate tea samples.
Assuntos
Bebidas/análise , Filtração/instrumentação , Filtração/métodos , Contaminação de Alimentos/análise , Ilex paraguariensis/química , Chumbo/análise , Poliuretanos , Calibragem , Precipitação Química , Concentração de Íons de Hidrogênio , Teste de Materiais , Espectrofotometria Atômica/métodosRESUMO
A method for the on-line preconcentration of copper using a minicolumn packed with activated carbon and its subsequent determination by inductively coupled plasma optical emission spectrometry (ICP-OES) coupled with flow injection (FI) was studied. In order to determinate the copper concentration present in parenteral solutions; it was retained on activated carbon (AC) at pH 9.5. A sensitivity enrichment factor of 30-fold was obtained with respect to the copper determination by ICP-OES without preconcentration. The detection limit for the preconcentration of 25 ml of sample was 0.1 microgl(-1). The precision for the ten replicate determinations at the 2.5 microgl(-1) Cu level was 3.0% relative standard deviation (R.S.D.), calculated with the peak heights. The calibration graph using the preconcentration method for cooper species was linear with a correlation coefficient of 0.9996 at levels near the detection limits up to at least 200 microgl(-1). The method was successfully applied to the determination of copper in parenteral solutions.
Assuntos
Carbono/química , Química Farmacêutica/métodos , Cobre/análise , Infusões Parenterais/instrumentação , Espectrofotometria Atômica/métodos , Espectrofotometria/métodos , Absorção , Soluções Tampão , Calibragem , Cromatografia , Cobre/química , Concentração de Íons de Hidrogênio , Reprodutibilidade dos Testes , Risco , Sensibilidade e Especificidade , Tecnologia Farmacêutica , Fatores de TempoRESUMO
The goal of this work was to apply a time-varying spectral approach to study the dynamic changes in Heart Rate Variability (HRV) produced by the arousal from sleep in obese patients with and without Obstructive Sleep Apnea (OSA). We studies 10 subjects, group I without OSA and group II with OSA diagnostic. RR intervals series was obtained from ECG records. HRV spectral indexes (HF & LF component) were computed from a time variant AR model. In general, group II has more variability than group I. Results are in agreement with literature for group I. However, group II results don't show statistical differences. Our preliminary results are comparable to others reported. Therefore, this technique allows characterizing transitory phenomena like cardiovascular response to arousals.
RESUMO
The objective of this work was to develop a method to determine the metal content in wine samples from the province of Mendoza in Argentina. Ten samples of white wine and 10 samples of red wine available in the supermarket were analyzed for the metals aluminium, cadmium, calcium, chromium, copper, iron, nickel, lead and zinc by electrothermal atomic spectrometry (ETAAS) and ultrasonic nebulization was coupled to inductively coupled plasma optical emission spectrometry (USN-ICP-OES). The aluminium, cadmium, calcium, copper, iron, lead, zinc, chromium concentrations were between 17.0-18.0 microg l(-1), 1.0-4.7microg l(-1), 10.0-15.0 mg l(-1), 23.0-28.0 microg l(-1), 480-790 microg l(-1), 50-90 microg l(-1), 24-130 microg l(-1), and <0.2-6.25 microg l(-1), respectively. The levels compare well with those reported for similar wines from some other parts of the world. A significant aspect in this paper is the samples mineralization step, which allowed the direct determination of the metals. Concerning to the Cd determination, a refluxing digestion system was used for the pretreatment of the samples.
Assuntos
Análise de Injeção de Fluxo/métodos , Contaminação de Alimentos/análise , Espectrofotometria Atômica/métodos , Oligoelementos/análise , Vinho/análise , Alumínio/análise , Argentina , Cádmio/análise , Cálcio/análise , Cromo/análise , Cobre/análise , Humanos , Ferro/análise , Chumbo/análise , Ultrassom , Zinco/análiseRESUMO
The purpose of this study is gain a better understanding of the anatomical variations of celiac artery and its branches in dogs. The celiac artery supply was analyzed in thirty dogs.The animals were injected with solution of Petrolatex S65 and dissected to evidence the celiac artery origin and its proximal ramifications. The celiac artery and its proximal branches were dissected and lengthen. The celiac artery more frequently emerged ahead of the first lumbar vertebra in one way form. The medium length of the celiac artery was of 0.98 cm. The gastrolienal trunk was the predominant morphological arrangement with medium length of 0.19 cm. The lienal artery emerged in one way form emitting more frequently 2 main branches. A branch emerging of the celiac artery irrigating the left adrenal occurred in 4 animals. The left gastric artery presented 1 branch in 17 animals (56.7%), 2 branches in 11 animals (36.6%) and 3 branches in 3 animals (10%). The left pancreatic lobe received a main branch from the lienal artery in 24 animals (80.0%), two branches in 4 animals (13.4%), and a branch emerging of the gastrolienal trunk in 2 animals (6.6%). The present data should therefore provide important information for devising experiments and interpreting results when using the mongred dogs as a model for experimental surgery and radiolocal practice of the celiac artery specially when making comparisons to human anatomy.
El propósito de este estudio es comprender mejor las variaciones anatómicas de la arteria celiaca y de sus ramas en los perros. Estudiamos la arteria celiaca en 30 perros (Canis familiaris). La parte abdominal de la aorta y el tronco celiaco fueron inyectados con una solución de Petrolatex S65, disecándose, desde su origen, la arteria celiaca y sus ramificaciones proximales. La arteria celiaca se originaba, de manera más frecuente, a nivel de la primera vértebra lumbar. La longitud media de la arteria celiaca fue de 0.98 cm. El tronco gastrolienal era el elemento morfológico predominante, con una longitud promedio de 0.19 cm. La arteria lienal se originaba de un tronco y emitía, frecuentemente, dos ramas principales. En 4 animales, se originaba una rama de la arteria celiaca, la cual irrigaba la glándula adrenal izquierda. La arteria gástrica izquierda emitía una rama en 17 animales (56.7%), dos ramas en 11 animales (36.6%) y 3 ramas en 3 animales (10%). El lóbulo pancreático izquierdo recibía una rama principal de la arteria lienal en 24 animales (80.0%), 2 ramas en 4 animales (13.4%), y una rama que se originaba del tronco gastrolienal en 2 animales (6.6%). Los resultados obtenidos se deben tener presentes cuando son utilizados perros como modelo en cirugía experimental y práctica radiolocal, especialmente, cuando se hacen comparaciones con la anatomía humana.