RESUMEN

Cigarette filters were utilized as carbon source for the production of solid carbon acid catalysts. In this study, the process of carbonization and simultaneous sulfonation via hydrothermal treatment was employed. The catalysts were prepared by mixing cigarette filters and sulfuric acid at temperatures of 100, 150, and 190 °C for durations ranging from 2 to 8 h. It was observed that the highest conversion of oleic acid occurred when the catalyst was synthesized at 190 °C for 4 h. The optimized conditions for the esterification reaction using this catalyst included an oleic acid to methanol molar ratio of 1:12, a catalyst loading of 5 wt%, and a temperature of 100 °C for 1 h. Additionally, the catalyst was successfully reused four times without significantly impacting the reaction yield. These findings highlight a promising approach for the utilization of waste materials, with immediate implications for waste management practices and positive environmental impacts.

Asunto(s)

Biocombustibles , Ácido Oléico , Esterificación , Temperatura , Catálisis , Carbono

RESUMEN

The increase in burning, deforestation, and the exorbitant use of fossil fuels have contributed to the increase in carbon dioxide emissions; this gas is responsible for the intensification of the greenhouse effect and radical climate changes. In this way, it becomes necessary to find alternatives to reduce its emission. Porous carbon materials synthesized from lignocellulosic waste can be employed in technologies for capture and utilization of CO2 due to the advantages such as selectivity, low-cost synthesis, high surface area and pore volume, and thermal and chemical stability. Considering the availability of Brazil nut biomass residues in the Amazon region, this article proposes to synthesize activated carbon from the lignocellulosic residue using physical and chemical activation methods for CO2 capture. The analysis of N2 adsorption-desorption isotherms proves the predominance of a microporous structure when using the two synthesis methods described here. In physical activation, the surface area was 912 m2/g, while, in chemical activation, it was 1421 to 2730 m2/g. The sample treated via the chemical method (BS6-K1) showed better performance in CO2 adsorption, with adsorption results of 3.8 and 6 mmol/g of CO2 at 25 ℃ and 0 °C, respectively, at 101 kPa. CO2 adsorption capacity is due to the high volume of ultramicropores. It is believed that the microporous carbon material synthesized from Brazil nut residues is an alternative precursor for carbon materials used as CO2 capture.

Asunto(s)

Bertholletia , Dióxido de Carbono , Dióxido de Carbono/química , Adsorción , Porosidad , Carbón Orgánico

RESUMEN

In rats, lisdexamfetamine (LDX) induces manic-like behaviors such as hyperlocomotion and increases in appetitive 50-kHz ultrasonic vocalizations (USV), which are prevented by antimanic drugs, such as lithium. Inhibition of glycogen synthase kinase 3 beta (GSK3ß) and antioxidant activity have been associated with antimanic effects. Thus, the aim of the present study was to evaluate the possible antimanic-like effects of andrographolide (ANDRO), a GSK3ß inhibitor, on LDX-induced hyperlocomotion and 50-kHz USV increases. In addition, the effect of ANDRO was studied on LDX-induced oxidative stress. Lithium was used as positive control. Adult Wistar rats were treated with vehicle, lithium (100 mg/kg i.p., daily) or ANDRO (2 mg/kg i.p., 3 times a week) for 21 days. On the test day, either 10 mg/kg LDX or saline was administered i.p. and USV and locomotor activity were recorded. LDX administration increased the number of 50-kHz calls, as well as locomotor activity. Repeated treatment with lithium or ANDRO prevented these effects of LDX on 50-kHz USV and locomotor activity. LDX increased lipid peroxidation (LPO) levels in rat striatum and both lithium and ANDRO prevented this effect. LPO levels in rat striatum were positively correlated with increases in 50-kHz USV emission as well as hyperlocomotion. In conclusion, the present results indicate that ANDRO has antimanic-like effects, which may be mediated by its antioxidant properties.

Asunto(s)

Trastorno Bipolar , Ultrasonido , Animales , Antimaníacos/farmacología , Antimaníacos/uso terapéutico , Trastorno Bipolar/inducido químicamente , Trastorno Bipolar/tratamiento farmacológico , Modelos Animales de Enfermedad , Diterpenos , Manía , Estrés Oxidativo , Ratas , Ratas Wistar , Vocalización Animal

RESUMEN

Staphylococcus aureus is one of the main pathogens found in cheeses produced with raw milk, including Minas artisanal cheese from Brazil. However, information about S. aureus isolated from artisanal cheeses and its sources of production in small-scale dairies is very limited. We aimed to characterize the virulence factors of S. aureus isolated from raw milk, endogenous starter culture, Minas artisanal cheese, and cheese handlers from the region of Campo das Vertentes, Minas Gerais, Brazil. We identified the staphylococcal isolates by MALDI-TOF mass spectrometry. We evaluated biofilm production on Congo red agar and polystyrene plates. We used PCR to detect icaA, icaB, icaC, sea, seb, sec, sed, see, tsst-1, agr, and mecA. We evaluated the expression of staphylococcal toxin genes in PCR-positive staphylococcal isolates using quantitative reverse-transcription PCR, and we evaluated the production of these toxins and their hemolytic activity in vitro. We also evaluated the antimicrobial resistance profile of the staphylococcal isolates. For statistical analysis, we used cluster analysis, χ2 tests, and correspondence tests. We analyzed 76 staphylococcal isolates. According to PCR, 18.42, 18.42, 2.63, and 77.63% were positive for sea, tsst-1, sec, and agr, respectively. We found low expression of staphylococcal toxin genes according to quantitative reverse-transcription PCR, and only 2 staphylococcal isolates produced toxic shock syndrome toxins. A total of 43 staphylococcal isolates (56.58%) had hemolytic activity; 53 were biofilm-forming on Congo red agar (69.73%), and 62 on polystyrene plates (81.58%). None of the staphylococcal isolates expressed the mecA gene, and none presented a multi-drug resistance pattern. The highest resistance was observed for penicillin G (67.11%) in 51 isolates and for tetracycline (27.63%) in 21 isolates. The staphylococcal isolates we evaluated had toxigenic potential, with a higher prevalence of sea and tsst-1. Biofilm production was the main virulence factor of the studied bacteria. Six clusters were formed whose distribution frequencies differed for hemolytic activity, biofilm formation (qualitative and quantitative analyses), and resistance to penicillin, tetracycline, and erythromycin. These findings emphasize the need for effective measures to prevent staphylococcal food poisoning by limiting S. aureus growth and enterotoxin formation throughout the food production chain and the final product.

Asunto(s)

Biopelículas/crecimiento & desarrollo , Queso/microbiología , Farmacorresistencia Bacteriana , Choque Séptico/microbiología , Intoxicación Alimentaria Estafilocócica/microbiología , Staphylococcus aureus/genética , Factores de Virulencia , Animales , Antibacterianos/farmacología , Toxinas Bacterianas/genética , Brasil , Enterotoxinas/genética , Staphylococcus aureus/efectos de los fármacos , Staphylococcus aureus/aislamiento & purificación , Staphylococcus aureus/patogenicidad , Superantígenos/genética

RESUMEN

Citrus fragrances have been used in aromatherapy for the treatment of anxiety, and the essential oil of Citrus sinensis (sweet orange) has shown promising results, although its mechanism of action was not known. The objective of this study was to evaluate the involvement of nitric oxide (NO) neurotransmission in the anxiolytic-like effect of C. sinensis essential oil. Swiss male mice were submitted to 15 min of C. sinensis essential oil inhalation (1%, 2.5%, 5%, and 10%) and tested in the marble-burying test, neophobia-induced hypophagia, and light/dark test. Locomotor activity was evaluated in an automated locomotor activity box. The coadministration of C. sinensis essential oil with L-arginine (200 mg/kg, i.p.), an NO precursor, was used for the behavioral evaluation of nitrergic system mediation. Additionally, the NO synthase activity was measured by nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) analysis in the cerebral cortex. C. sinensis essential oil exerted anxiolytic-like effect at dose that did not change locomotor activity. Moreover, L-arginine pretreatment prevented this anxiolytic-like effect on marble-burying test. Finally, C. sinensis essential oil reduced the NADPH-d positive cells. Thus, the nitrergic neurotransmission plays a relevant role in the anxiolytic-like effect C. sinensis essential oil.

Asunto(s)

Ansiolíticos/farmacología , Aromaterapia/métodos , Aceites de Plantas/farmacología , Transmisión Sináptica/efectos de los fármacos , Animales , Ansiedad/tratamiento farmacológico , Modelos Animales de Enfermedad , Masculino , Ratones , Actividad Motora/efectos de los fármacos

RESUMEN

Objective: To conduct the first support vector machine (SVM)-based study comparing the diagnostic accuracy of T1-weighted magnetic resonance imaging (T1-MRI), F-fluorodeoxyglucose-positron emission tomography (FDG-PET) and regional cerebral blood flow single-photon emission computed tomography (rCBF-SPECT) in Alzheimer's disease (AD). Method: Brain T1-MRI, FDG-PET and rCBF-SPECT scans were acquired from a sample of mild AD patients (n=20) and healthy elderly controls (n=18). SVM-based diagnostic accuracy indices were calculated using whole-brain information and leave-one-out cross-validation. Results: The accuracy obtained using PET and SPECT data were similar. PET accuracy was 68∼71% and area under curve (AUC) 0.77∼0.81; SPECT accuracy was 68∼74% and AUC 0.75∼0.79, and both had better performance than analysis with T1-MRI data (accuracy of 58%, AUC 0.67). The addition of PET or SPECT to MRI produced higher accuracy indices (68∼74%; AUC: 0.74∼0.82) than T1-MRI alone, but these were not clearly superior to the isolated neurofunctional modalities. Conclusion: In line with previous evidence, FDG-PET and rCBF-SPECT more accurately identified patients with AD than T1-MRI, and the addition of either PET or SPECT to T1-MRI data yielded increased accuracy. The comparable SPECT and PET performances, directly demonstrated for the first time in the present study, support the view that rCBF-SPECT still has a role to play in AD diagnosis.

Asunto(s)

Humanos , Masculino , Femenino , Anciano , Imagen por Resonancia Magnética/métodos , Tomografía Computarizada de Emisión de Fotón Único/métodos , Tomografía de Emisión de Positrones/métodos , Enfermedad de Alzheimer/diagnóstico por imagen , Máquina de Vectores de Soporte , Mapeo Encefálico , Estudios de Casos y Controles , Valor Predictivo de las Pruebas , Sensibilidad y Especificidad , Fluorodesoxiglucosa F18 , Escolaridad

RESUMEN

A fraction composed of an arabinan-rich pectin was extracted from acerola fruit (Malpighia emarginata) and named ACWS. This fraction presented 93% of total carbohydrate, relative molecular weight of 7.5×104g/mol, galacturonic acid, arabinose, galactose, xylose and rhamnose in 52.1:32.4:7.2:4.8:3.5 molar ratio and had its structure confirmed by NMR analysis. The anti-fatigue activity of ACWS was evaluated using the weight load swim test on trained mice. ACWS was orally administered at doses of 50mg/kg, 100mg/kg and 200mg/kg for 28days. Plasma biochemical parameters, respiration of permeabilized skeletal muscle fibers, and GSH levels and lipoperoxidation in the brain (pre-frontal cortex, hippocampus, striatum and hypothalamus) were determined. ACWS could lengthen the swimming time, increase the plasma levels of glucose, triglycerides, lactate, and the GSH levels in the hippocampus at all tested doses. The mitochondrial respiratory capacity of the skeletal muscle was increased at middle and high ACWS doses. This study provides strong evidence that M. emarginata pectic polysaccharide supplementation has anti-fatigue activity, can modify the kinetics of energy substrates (carbohydrate and fat) mobilization and the respiratory capacity of the skeletal muscle, as well the antioxidant status in the hippocampus of ACWS treated animals.

Asunto(s)

Malpighiaceae/química , Pectinas/química , Pectinas/farmacología , Polisacáridos/química , Animales , Biomarcadores , Encéfalo/efectos de los fármacos , Encéfalo/metabolismo , Respiración de la Célula/efectos de los fármacos , Frutas/química , Peroxidación de Lípido/efectos de los fármacos , Ratones , Músculos/efectos de los fármacos , Músculos/metabolismo , Estrés Oxidativo/efectos de los fármacos , Polisacáridos/farmacología , Especies Reactivas de Oxígeno/metabolismo

RESUMEN

OBJECTIVE: To conduct the first support vector machine (SVM)-based study comparing the diagnostic accuracy of T1-weighted magnetic resonance imaging (T1-MRI), F-fluorodeoxyglucose-positron emission tomography (FDG-PET) and regional cerebral blood flow single-photon emission computed tomography (rCBF-SPECT) in Alzheimer's disease (AD). METHOD: Brain T1-MRI, FDG-PET and rCBF-SPECT scans were acquired from a sample of mild AD patients (n=20) and healthy elderly controls (n=18). SVM-based diagnostic accuracy indices were calculated using whole-brain information and leave-one-out cross-validation. RESULTS: The accuracy obtained using PET and SPECT data were similar. PET accuracy was 68∼71% and area under curve (AUC) 0.77∼0.81; SPECT accuracy was 68∼74% and AUC 0.75∼0.79, and both had better performance than analysis with T1-MRI data (accuracy of 58%, AUC 0.67). The addition of PET or SPECT to MRI produced higher accuracy indices (68∼74%; AUC: 0.74∼0.82) than T1-MRI alone, but these were not clearly superior to the isolated neurofunctional modalities. CONCLUSION: In line with previous evidence, FDG-PET and rCBF-SPECT more accurately identified patients with AD than T1-MRI, and the addition of either PET or SPECT to T1-MRI data yielded increased accuracy. The comparable SPECT and PET performances, directly demonstrated for the first time in the present study, support the view that rCBF-SPECT still has a role to play in AD diagnosis.

Asunto(s)

Enfermedad de Alzheimer/diagnóstico por imagen , Imagen por Resonancia Magnética/métodos , Tomografía de Emisión de Positrones/métodos , Máquina de Vectores de Soporte , Tomografía Computarizada de Emisión de Fotón Único/métodos , Anciano , Mapeo Encefálico , Estudios de Casos y Controles , Escolaridad , Femenino , Fluorodesoxiglucosa F18 , Humanos , Masculino , Valor Predictivo de las Pruebas , Sensibilidad y Especificidad

RESUMEN

The low fruit set is one of the main factors leading to poor yield of pear orchards in Brazil. The exogenous application of thidiazuron (TDZ) and aminoethoxyvinilglycine (AVG) has shown promising results in some pear cultivars and other temperate fruit trees. The objective of this study was to evaluate the effect of TDZ and AVG on fruit set, yield, and fruit quality of 'Hosui' and 'Packham's Triumph' pears. The study was performed in a commercial orchard located in São Joaquim, SC. Plant material consisted of 'Hosui' and 'Packham's Triumph' pear trees grafted on Pyrus calleryana. Treatments consisted on different rates of TDZ (0 mg L-1, 20 mg L-1, 40 mg L-1 and 60 mg L-1) sprayed at full bloom for both cultivars. An additional treatment of AVG 60 mg L-1 was sprayed one week after full bloom in 'Hosui'. The fruit set, number of fruit per tree, yield, fruit weight, seed number, and fruit quality attributes were assessed. Fruit set and yield of both cultivars are consistently increased by TDZ, within the rates of 20 to 60 mg L-1. Besides, its application increased fruit size of 'Hosui' and did not negatively affect fruit quality attributes of both cultivars.

Asunto(s)

Glicina/análogos & derivados , Compuestos de Fenilurea/farmacología , Pyrus/efectos de los fármacos , Tiadiazoles/farmacología , Producción de Cultivos , Glicina/administración & dosificación , Glicina/farmacología , Compuestos de Fenilurea/administración & dosificación , Pyrus/crecimiento & desarrollo , Tiadiazoles/administración & dosificación

RESUMEN

ABSTRACT The low fruit set is one of the main factors leading to poor yield of pear orchards in Brazil. The exogenous application of thidiazuron (TDZ) and aminoethoxyvinilglycine (AVG) has shown promising results in some pear cultivars and other temperate fruit trees. The objective of this study was to evaluate the effect of TDZ and AVG on fruit set, yield, and fruit quality of 'Hosui' and 'Packham's Triumph' pears. The study was performed in a commercial orchard located in São Joaquim, SC. Plant material consisted of 'Hosui' and 'Packham's Triumph' pear trees grafted on Pyrus calleryana. Treatments consisted on different rates of TDZ (0 mg L-1, 20 mg L-1, 40 mg L-1 and 60 mg L-1) sprayed at full bloom for both cultivars. An additional treatment of AVG 60 mg L-1 was sprayed one week after full bloom in 'Hosui'. The fruit set, number of fruit per tree, yield, fruit weight, seed number, and fruit quality attributes were assessed. Fruit set and yield of both cultivars are consistently increased by TDZ, within the rates of 20 to 60 mg L-1. Besides, its application increased fruit size of 'Hosui' and did not negatively affect fruit quality attributes of both cultivars.

Asunto(s)

Compuestos de Fenilurea/farmacología , Tiadiazoles/farmacología , Pyrus/efectos de los fármacos , Glicina/análogos & derivados , Compuestos de Fenilurea/administración & dosificación , Tiadiazoles/administración & dosificación , Pyrus/crecimiento & desarrollo , Producción de Cultivos , Glicina/administración & dosificación , Glicina/farmacología

RESUMEN

AIMS: Increases in protein kinase C (PKC) and oxidative stress have been related to mania. Drugs with antioxidant effects or inhibitory actions on PKC may have antimanic effects. The flavonoid quercetin has antioxidant and PKC-inhibiting effects that resemble those of lithium, the first-line treatment for mania in bipolar disorder. We hypothesized that quercetin may have antimanic-like effects in an animal model. MAIN METHODS: In the present study, we investigated the effects of acute and chronic treatment with quercetin (2.5, 5, 10, and 40mg/kg, i.p.) in male Swiss mice that were subjected to methylphenidate (5mg/kg, i.p.)-induced hyperlocomotion, an animal model of mania. Lithium (100mg/kg, i.p.) and diazepam (5mg/kg, i.p.) were used as positive and negative controls, respectively. We also evaluated the effects of these treatments on methylphenidate-induced oxidative stress in the brain by measuring reduced glutathione (GSH) and lipid peroxidation (LPO) levels in the prefrontal cortex, hippocampus, and striatum. KEY FINDINGS: Acute and chronic (21-day) treatment with lithium and diazepam reduced methylphenidate-induced hyperlocomotion. Chronic but not acute treatment with quercetin (10 and 40mg/kg) blocked methylphenidate-induced hyperlocomotion. These effects of lithium and quercetin occurred at doses that did not alter spontaneous locomotor activity, whereas diazepam reduced spontaneous locomotor activity. Chronic treatment with lithium and quercetin blocked the methylphenidate-induced increase in LPO levels in the striatum. SIGNIFICANCE: These results suggest that chronic quercetin treatment has antimanic-like and antioxidant effects, thus encouraging further studies of quercetin as a putative new antimanic drug.

Asunto(s)

Locomoción/efectos de los fármacos , Metilfenidato/toxicidad , Estrés Oxidativo/efectos de los fármacos , Quercetina/administración & dosificación , Animales , Conducta Animal/efectos de los fármacos , Encéfalo/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Masculino , Ratones

RESUMEN

Knowledge of contagion among economies is a relevant issue in economics. The canonical model of contagion is an alternative in this case. Given the existence of endogenous variables in the model, instrumental variables can be used to decrease the bias of the OLS estimator. In the presence of heteroskedastic disturbances this paper proposes the use of conditional volatilities as instruments. Simulation is used to show that the homoscedastic and heteroskedastic estimators which use them as instruments have small bias. These estimators are preferable in comparison with the OLS estimator and their asymptotic distribution can be used to construct confidence intervals.

Asunto(s)

Interpretación Estadística de Datos , Modelos Económicos , Modelos Estadísticos , Simulación por Computador , Humanos

RESUMEN

Coagulase-negative staphylococci (CNS) represent one of the most prevalent microorganisms in nosocomial infections worldwide, nevertheless little is known about their pathogenicity features. Thus, our aim was to characterize virulence aspects of CNS isolated from patients with bloodstream infections assisted in hospitals of Belo Horizonte, MG, Brazil. Strains were identified using bioMérieuxVitek® and for biofilm production evaluation, Congo Red Agar (CRA) and polystyrene plates were used. PCR was applied to detect icaA, icaB, icaC, atlE, sea, sec, sed, tsst-1 and agr. For statistical analyses were used hierarchical cluster, chi-square test and correspondence. 59 strains were analyzed, being S. haemolyticus the most prevalent. On CRA, 96.5% were biofilm producer, whereas on polystyrene plate, 100% showed adhesion at different times evaluated. Regarding genotypic analyses, 15.2%, 38.9%, 8.4%, 49.1%, 76.2%, 23.7%, 1.6%, 30.5% and 38.9% were positive for icaA, icaB, icaC, atlE, sea, sec, sed, tsst-1 and agr, respectively. Six clusters were formed and frequency distributions of agr, atlE, icaA, icaB, sea, sec, tsst-1 differed (P < 0.001). In conclusion, all strains were biofilm producer, with high prevalence of atlE, and had potential of toxin production, with high prevalence of sea. According to the group-analyses, icaB showed relationship with the strong adherence in samples.

Asunto(s)

Toxinas Bacterianas/análisis , Biopelículas/crecimiento & desarrollo , Sepsis/microbiología , Infecciones Estafilocócicas/microbiología , Staphylococcus/fisiología , Adhesión Bacteriana , Toxinas Bacterianas/genética , Técnicas de Tipificación Bacteriana , Brasil , Análisis por Conglomerados , Infección Hospitalaria/microbiología , Genotipo , Hospitales , Humanos , Reacción en Cadena de la Polimerasa , Staphylococcus/clasificación , Staphylococcus/aislamiento & purificación , Staphylococcus/metabolismo , Factores de Virulencia/análisis , Factores de Virulencia/genética

RESUMEN

Quercetin is a known antioxidant and protein kinase C (PKC) inhibitor. Previous studies have shown that mania involves oxidative stress and an increase in PKC activity. We hypothesized that quercetin affects manic symptoms. In the present study, manic-like behavior (hyperlocomotion) and oxidative stress were induced by 24h paradoxical sleep deprivation (PSD) in male Swiss mice. Both 10 and 40mg/kg quercetin prevented PSD-induced hyperlocomotion. Quercetin reversed the PSD-induced decrease in glutathione (GSH) levels in the prefrontal cortex (PFC) and striatum. Quercetin also reversed the PSD-induced increase in lipid peroxidation (LPO) in the PFC, hippocampus, and striatum. Pearson's correlation analysis revealed a negative correlation between locomotor activity and GSH in the PFC in sleep-deprived mice and a positive correlation between locomotor activity and LPO in the PFC and striatum in sleep-deprived mice. These results suggest that quercetin exerts an antimanic-like effect at doses that do not impair spontaneous locomotor activity, and the antioxidant action of quercetin might contribute to its antimanic-like effects.

Asunto(s)

Antimaníacos/farmacología , Antioxidantes/farmacología , Trastorno Bipolar/tratamiento farmacológico , Estrés Oxidativo/efectos de los fármacos , Agitación Psicomotora/tratamiento farmacológico , Quercetina/farmacología , Animales , Trastorno Bipolar/etiología , Trastorno Bipolar/metabolismo , Trastorno Bipolar/fisiopatología , Cuerpo Estriado/efectos de los fármacos , Cuerpo Estriado/metabolismo , Modelos Animales de Enfermedad , Esquema de Medicación , Glutatión/agonistas , Glutatión/metabolismo , Hipocampo/efectos de los fármacos , Hipocampo/metabolismo , Peroxidación de Lípido/efectos de los fármacos , Masculino , Ratones , Corteza Prefrontal/efectos de los fármacos , Corteza Prefrontal/metabolismo , Agitación Psicomotora/etiología , Agitación Psicomotora/metabolismo , Agitación Psicomotora/fisiopatología , Privación de Sueño/complicaciones , Privación de Sueño/metabolismo , Privación de Sueño/fisiopatología

RESUMEN

Objective: To review functional neuroimaging studies about the relationship between cardiovascular risk factors (CVRFs), Alzheimer's disease (AD), and mild cognitive impairment (MCI). Methods: We performed a comprehensive literature search to identify articles in the neuroimaging field addressing CVRF in AD and MCI. We included studies that used positron emission tomography (PET), single photon emission computerized tomography (SPECT), or functional magnetic resonance imaging (fMRI). Results: CVRFs have been considered risk factors for cognitive decline, MCI, and AD. Patterns of AD-like changes in brain function have been found in association with several CVRFs (both regarding individual risk factors and also composite CVRF measures). In vivo assessment of AD-related pathology with amyloid imaging techniques provided further evidence linking CVRFs and AD, but there is still limited information resulting from this new technology. Conclusion: There is a large body of evidence from functional neuroimaging studies supporting the hypothesis that CVRFs may play a causal role in the pathophysiology of AD. A major limitation of most studies is their cross-sectional design; future longitudinal studies using multiple imaging modalities are expected to better document changes in CVRF-related brain function patterns and provide a clearer picture of the complex relationship between aging, CVRFs, and AD. .

Asunto(s)

Humanos , Enfermedad de Alzheimer/fisiopatología , Enfermedades Cardiovasculares/fisiopatología , Neuroimagen Funcional/métodos , Disfunción Cognitiva/fisiopatología , Enfermedad de Alzheimer/diagnóstico , Enfermedades Cardiovasculares/diagnóstico , Imagen por Resonancia Magnética/métodos , Disfunción Cognitiva/diagnóstico , Tomografía de Emisión de Positrones/métodos , Factores de Riesgo , Tomografía Computarizada de Emisión de Fotón Único/métodos

RESUMEN

OBJECTIVE: To review functional neuroimaging studies about the relationship between cardiovascular risk factors (CVRFs), Alzheimer's disease (AD), and mild cognitive impairment (MCI). METHODS: We performed a comprehensive literature search to identify articles in the neuroimaging field addressing CVRF in AD and MCI. We included studies that used positron emission tomography (PET), single photon emission computerized tomography (SPECT), or functional magnetic resonance imaging (fMRI). RESULTS: CVRFs have been considered risk factors for cognitive decline, MCI, and AD. Patterns of AD-like changes in brain function have been found in association with several CVRFs (both regarding individual risk factors and also composite CVRF measures). In vivo assessment of AD-related pathology with amyloid imaging techniques provided further evidence linking CVRFs and AD, but there is still limited information resulting from this new technology. CONCLUSION: There is a large body of evidence from functional neuroimaging studies supporting the hypothesis that CVRFs may play a causal role in the pathophysiology of AD. A major limitation of most studies is their cross-sectional design; future longitudinal studies using multiple imaging modalities are expected to better document changes in CVRF-related brain function patterns and provide a clearer picture of the complex relationship between aging, CVRFs, and AD.

Asunto(s)

Enfermedad de Alzheimer/fisiopatología , Enfermedades Cardiovasculares/fisiopatología , Disfunción Cognitiva/fisiopatología , Neuroimagen Funcional/métodos , Enfermedad de Alzheimer/diagnóstico , Enfermedades Cardiovasculares/diagnóstico , Disfunción Cognitiva/diagnóstico , Humanos , Imagen por Resonancia Magnética/métodos , Tomografía de Emisión de Positrones/métodos , Factores de Riesgo , Tomografía Computarizada de Emisión de Fotón Único/métodos

RESUMEN

Recent neuroanatomical pattern classification studies have attempted to individually classify cases with psychotic disorders using morphometric MRI data in an automated fashion. However, this approach has not been tested in population-based samples, in which variable patterns of comorbidity and disease course are typically found. We aimed to evaluate the diagnostic accuracy (DA) of the above technique to discriminate between incident cases of first-episode schizophrenia identified in a circumscribed geographical region over a limited period of time, in comparison with next-door healthy controls. Sixty-two cases of first-episode schizophrenia or schizophreniform disorder and 62 age, gender and educationally-matched controls underwent 1.5 T MRI scanning at baseline, and were naturalistically followed-up over 1 year. T1-weighted images were used to train a high-dimensional multivariate classifier, and to generate both spatial maps of the discriminative morphological patterns between groups and ROC curves. The spatial map discriminating first-episode schizophrenia patients from healthy controls revealed a complex pattern of regional volumetric abnormalities in the former group, affecting fronto-temporal-occipital gray and white matter regions bilaterally, including the inferior fronto-occipital fasciculus, as well as the third and lateral ventricles. However, an overall modest DA (73.4%) was observed for the individual discrimination between first-episode schizophrenia patients and controls, and the classifier failed to predict 1-year prognosis (remitting versus non-remitting course) of first-episode schizophrenia (DA=58.3%). In conclusion, using a "real world" sample recruited with epidemiological methods, the application of a neuroanatomical pattern classifier afforded only modest DA to classify first-episode schizophrenia subjects and next-door healthy controls, and poor discriminative power to predict the 1-year prognosis of first-episode schizophrenia.

Asunto(s)

Encéfalo/patología , Esquizofrenia/clasificación , Esquizofrenia/patología , Adolescente , Adulto , Antipsicóticos/uso terapéutico , Área Bajo la Curva , Mapeo Encefálico , Manual Diagnóstico y Estadístico de los Trastornos Mentales , Reacciones Falso Positivas , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Neuroimagen , Población , Valor Predictivo de las Pruebas , Escalas de Valoración Psiquiátrica , Curva ROC , Reproducibilidad de los Resultados , Esquizofrenia/tratamiento farmacológico , Psicología del Esquizofrénico , Máquina de Vectores de Soporte , Adulto Joven

RESUMEN

Differential scanning calorimetry (DSC) and a Rancimat method apparatus were applied to evaluate the oxidative stability of buriti pulp oil (Mauritia flexuosa Mart), rubber seed oil (Hevea brasiliensis), and passion fruit oil (Passiflora edulis). The Rancimat measurements taken for the oxidative induction times were performed under isothermal conditions at 100°C and in an air atmosphere. The DSC technique involved the oxidation of oil samples in an oxygen-flow DSC cell. The DSC cell temperature was set at five different isothermal temperatures: 100, 110, 120, 130 and 140°C. During the oxidation reaction, an increase in heat was observed as a sharp exothermic curve. The value T(0) represents the oxidative induction time, which is determined from the downward extrapolated DSC oxidative curve verses the time axis. These curves indicate a good correlation between the DSC T(0) and oxidative stability index (OSI) values. The DSC method is useful because it consumes less time and less sample.

Asunto(s)

Rastreo Diferencial de Calorimetría/métodos , Aceites de Plantas/química , Cromatografía de Gases , Ácidos Grasos/análisis , Oxidación-Reducción , América del Sur , Termogravimetría

RESUMEN

The identification of biological markers at early stages of Alzheimer's disease (AD) contributes to diagnostic accuracy and adds prognostic value. However, in spite of recent developments, results of neurostructural imaging studies on predicting conversion to AD are not uniform. We conducted a systematic review of voxel-based morphometry (VBM) studies about the neurostructural predictors of conversion to AD. Ten studies met inclusion criteria and nine reported baseline regional gray matter (GM) atrophy in mild cognitive impairment (MCI) or healthy subjects who progressed to AD. Using the method of Activation Likelihood Estimation, we meta-analyzed the coordinates from the six longitudinal VBM studies that enrolled subjects with amnestic MCI (aMCI) at baseline. These comprised a total of 429 aMCI subjects, of which 142 converted to AD. Meta-analysis yielded one significant cluster of GM volumetric reduction in aMCI patients who converted to AD, located in the left hippocampus and parahippocampal gyrus. In conclusion, left medial temporal lobe atrophy is the most consistent neurostructural biomarker to predict conversion from aMCI to AD.

Asunto(s)

Enfermedad de Alzheimer/diagnóstico , Encéfalo/patología , Enfermedad de Alzheimer/complicaciones , Trastornos del Conocimiento/etiología , Humanos , Neuroimagen/métodos , Valor Predictivo de las Pruebas

RESUMEN

The present study aimed to investigate the presence of corpus callosum (CC) volume deficits in a population-based recent-onset psychosis (ROP) sample, and whether CC volume relates to interhemispheric communication deficits. For this purpose, we used voxel-based morphometry comparisons of magnetic resonance imaging data between ROP (n =122) and healthy control (n = 94) subjects. Subgroups (38 ROP and 39 controls) were investigated for correlations between CC volumes and performance on the Crossed Finger Localization Test (CFLT). Significant CC volume reductions in ROP subjects versus controls emerged after excluding substance misuse and non-right-handedness. CC reductions retained significance in the schizophrenia subgroup but not in affective psychoses subjects. There were significant positive correlations between CC volumes and CFLT scores in ROP subjects, specifically in subtasks involving interhemispheric communication. From these results, we can conclude that CC volume reductions are present in association with ROP. The relationship between such deficits and CFLT performance suggests that interhemispheric communication impairments are directly linked to CC abnormalities in ROP.

Asunto(s)

Trastornos del Conocimiento/etiología , Cuerpo Calloso/patología , Lateralidad Funcional/fisiología , Trastornos Psicóticos/complicaciones , Trastornos Psicóticos/patología , Transferencia de Experiencia en Psicología/fisiología , Adolescente , Adulto , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador/métodos , Imagen por Resonancia Magnética/métodos , Masculino , Persona de Mediana Edad , Pruebas Neuropsicológicas , Estadística como Asunto , Adulto Joven