N-Methyl-(2S, 4R)-trans-4-hydroxy-L-proline, the major bioactive compound from Sideroxylon obtusifolium, attenuates pilocarpine-induced injury in cultured astrocytes.

Glial cells have been implicated in temporal lobe epilepsy in humans and in its models. Astrocytes are lost in several brain regions after acute seizures induced by pilocarpine and may suffer hyperplasia at subsequent time points. This study investigated the effect of N-methyl-(2S,4R)-trans-4-hydroxy-L-proline (NMP) on astrocytes exposed to cytotoxic concentrations of pilocarpine. Astrocytes were incubated with pilocarpine (half maximal inhibitory concentration (IC50)=31.86 mM) for 24 h. Afterwards, they were treated with NMP at concentrations ranging from 3.12 to 100 µg/mL for 24 h. Cell viability was assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cytoplasmic reactive oxygen species (ROS) and mitochondrial transmembrane potential (ΔΨm) were analyzed by flow cytometry using 2',7'-dichlorofluorescein diacetate (DCFH-DA) and rhodamine-123 (Rho123), respectively. Expression of glial fibrillary acidic protein (GFAP) and voltage-dependent anion channel-1 (VDAC-1) were measured by western blot. Pilocarpine significantly decreased cell viability and mitochondrial potential and increased ROS concentration significantly by 6.7 times compared to the control. NMP concentrations ≥25 µg/mL protected astrocytes against pilocarpine-induced injury in a concentration-dependent manner. Concomitantly, NMP reduced cytoplasmic ROS accumulation to 27.3, 24.8, and 12.3% in the groups treated with 25, 50, and 100 µg/mL NMP, respectively. NMP also protected mitochondria from pilocarpine-induced depolarization. These effects were associated with improvement of pilocarpine-induced GFAP and VDAC-1 overexpression, which are important biomarkers of astrocyte dysfunction. In conclusion, the improvement of ROS accumulation, VDAC-1 overexpression, and mitochondrial depolarization are possible mechanisms of the NMP protective action on reactive astrocytes.

N-Methyl-(2S, 4R)-trans-4-hydroxy-L-proline, the major bioactive compound from Sideroxylon obtusifolium, attenuates pilocarpine-induced injury in cultured astrocytes

Glial cells have been implicated in temporal lobe epilepsy in humans and in its models. Astrocytes are lost in several brain regions after acute seizures induced by pilocarpine and may suffer hyperplasia at subsequent time points. This study investigated the effect of N-methyl-(2S,4R)-trans-4-hydroxy-L-proline (NMP) on astrocytes exposed to cytotoxic concentrations of pilocarpine. Astrocytes were incubated with pilocarpine (half maximal inhibitory concentration (IC50)=31.86 mM) for 24 h. Afterwards, they were treated with NMP at concentrations ranging from 3.12 to 100 μg/mL for 24 h. Cell viability was assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cytoplasmic reactive oxygen species (ROS) and mitochondrial transmembrane potential (ΔΨm) were analyzed by flow cytometry using 2',7'-dichlorofluorescein diacetate (DCFH-DA) and rhodamine-123 (Rho123), respectively. Expression of glial fibrillary acidic protein (GFAP) and voltage-dependent anion channel-1 (VDAC-1) were measured by western blot. Pilocarpine significantly decreased cell viability and mitochondrial potential and increased ROS concentration significantly by 6.7 times compared to the control. NMP concentrations ≥25 µg/mL protected astrocytes against pilocarpine-induced injury in a concentration-dependent manner. Concomitantly, NMP reduced cytoplasmic ROS accumulation to 27.3, 24.8, and 12.3% in the groups treated with 25, 50, and 100 µg/mL NMP, respectively. NMP also protected mitochondria from pilocarpine-induced depolarization. These effects were associated with improvement of pilocarpine-induced GFAP and VDAC-1 overexpression, which are important biomarkers of astrocyte dysfunction. In conclusion, the improvement of ROS accumulation, VDAC-1 overexpression, and mitochondrial depolarization are possible mechanisms of the NMP protective action on reactive astrocytes.

Air ingestion by a buckled viscous jet of silicone oil impacting the free surface of the same liquid.

As frequently observed in common life, a jet of a viscous liquid impacting on a horizontal surface does not remain straight but instead buckles and folds periodically. We report experiments with planar (ribbonlike) jets of silicone oil impacting the free surface of the same liquid and describe the way in which jet folds incorporate air. It is shown that air ingestion proceeds through different modes, each of them acting as a source of monodisperse bubbles and featuring a threshold in jet height. These sources result from the breakup of remarkable cuspidal structures, produced by the recession of air domains within liquid folds.

Lifelong immunization with human beta-amyloid (1-42) protects Alzheimer's transgenic mice against cognitive impairment throughout aging.

Although both active and passive beta-amyloid (Abeta) immunotherapy have been shown to protect against or lessen cognitive impairment in various Alzheimer's transgenic mouse lines, these studies have focused on a single task and involved standard statistical analysis. Because Alzheimer's disease impacts multiple cognitive domains, the current study employed an extensive behavioral battery and multimetric analysis therein to determine the impact of Abeta immunization given throughout most of adult life (from 2-16 1/2 months of age) to APP+PS1 transgenic mice. At both adult (4 1/2-6 month) and aged (15-16 1/2 month) test points, the same 6-week behavioral battery was administered. Results indicate that Abeta immunotherapy partially or completely protected APP+PS1 mice at both test points from otherwise impaired performance in a variety of tasks spanning multiple cognitive domains (reference learning/memory, working memory, search/recognition). At both adult and aged test points, the cognitive benefits of Abeta immunotherapy were evident even when behavioral measures were analyzed collectively (as "overall" performance) through discriminant function analysis. Since behavioral protection at the 15-16 1/2 month test point occurred without a decrease in (or correlation to) Abeta deposition, the mechanism of Abeta immunotherapy's action most likely involves neutralization/removal of small Abeta oligomers from the brain. However, in factor analysis performed at this aged test point, brain Abeta deposition measures loaded heavily with key cognitive measures. Collectively, our results suggest that the entire process of Abeta deposition deleteriously impacts cognitive performance and that Abeta-based preventative strategies can provide long-term cognitive benefits extending well into older age.