51 research outputs found
Cognitive-enhancing properties of Morinda lucida (Rubiaceae) and Peltophorum pterocarpum (Fabaceae) in scopolamine-induced amnesic mice
Background: Cognitive disorders associated with aging have been successfully managed by African traditional medical practitioners using various plants. This study evaluated the cognitive enhancing potentials of Morinda lucida (L) Rubiaceae and Peltophorum pterocarpum (DC) ex. K Heyne in scopolamine induced amnesic animals.Materials and Methods: The anti-amnesic activity of the ethyl acetate extracts of Morinda lucida and Peltophorum pterocarpum at doses of 4 mg/kg, 6 mg/kg and 8 mg/kg were assessed in scopolamine induced amnesic mice using Morris water maze test model. Effect of the extracts on the histology of the hippocampus was also evaluated.Results: The ethyl acetate extract of Morinda lucida and Peltophorum pterocarpum ameliorated scopolamine induced memory deficit in the animals under study. There was no effect of the extract on the histology of the hippocampus. However, there was an increase in the density of cells in the hippocampus of treated group as compared to the untreated.Conclusion: Morinda lucida and Peltophorum pterocarpum showed considerable enhancement of cognition in scopolamine induced amnesic mice.Keywords: Morinda lucida, Peltophorum pterocarpum, Morris water maze, Scopolamine, Hippocampu
Brain Viscoelasticity Alteration in Chronic-Progressive Multiple Sclerosis
Introduction: Viscoelastic properties indicate structural alterations in biological tissues at multiple scales with high sensitivity. Magnetic Resonance Elastography (MRE) is a novel technique that directly visualizes and quantitatively measures biomechanical tissue properties in vivo. MRE recently revealed that early relapsing-remitting multiple sclerosis (MS) is associated with a global decrease of the cerebral mechanical integrity. This study addresses MRE and MR volumetry in chronic-progressive disease courses of MS
The role of structural viscoelasticity in deformable porous media with incompressible constituents: applications in biomechanics
The main goal of this work is to clarify and quantify, by means of
mathematical analysis, the role of structural viscoelasticity in the
biomechanical response of deformable porous media with incompressible
constituents to sudden changes in external applied loads. Models of deformable
porous media with incompressible constituents are often utilized to describe
the behavior of biological tissues, such as cartilages, bones and engineered
tissue scaffolds, where viscoelastic properties may change with age, disease or
by design. Here, for the first time, we show that the fluid velocity within the
medium could increase tremendously, even up to infinity, should the external
applied load experience sudden changes in time and the structural
viscoelasticity be too small. In particular, we consider a one-dimensional
poro-visco-elastic model for which we derive explicit solutions in the cases
where the external applied load is characterized by a step pulse or a
trapezoidal pulse in time. By means of dimensional analysis, we identify some
dimensionless parameters that can aid the design of structural properties
and/or experimental conditions as to ensure that the fluid velocity within the
medium remains bounded below a certain given threshold, thereby preventing
potential tissue damage. The application to confined compression tests for
biological tissues is discussed in detail. Interestingly, the loss of
viscoelastic tissue properties has been associated with various disease
conditions, such as atherosclerosis, Alzheimer's disease and glaucoma. Thus,
the findings of this work may be relevant to many applications in biology and
medicine
The influence of physiological aging and atrophy on brain viscoelastic properties in humans
Physiological aging of the brain is accompanied by ubiquitous degeneration of neurons and oligodendrocytes. An alteration of the cellular matrix of an organ impacts its macroscopic viscoelastic properties which can be detected by magnetic resonance elastography (MRE)--to date the only method for measuring brain mechanical parameters without intervention. However, the wave patterns detected by MRE are affected by atrophic changes in brain geometry occurring in an individual's life span. Moreover, regional variability in MRE-detected age effects is expected corresponding to the regional variation in atrophy. Therefore, the sensitivity of brain MRE to brain volume and aging was investigated in 66 healthy volunteers aged 18-72. A linear decline in whole-brain elasticity was observed (-0.75%/year, R-square = 0.59, p<0.001); the rate is three times that determined by volume measurements (-0.23%/year, R-square = 0.4, p<0.001). The highest decline in elasticity (-0.92%/year, R-square = 0.43, p<0.001) was observed in a region of interest placed in the frontal lobe with minimal age-related shrinkage (-0.1%, R-square = 0.06, p = 0.043). Our results suggest that cerebral MRE can measure geometry-independent viscoelastic parameters related to intrinsic tissue structure and altered by age
Rheological properties of porcine organs: measurements and fractional viscoelastic model
The rheological properties of porcine heart, kidney, liver and brain were measured using dynamic oscillatory shear tests over a range of frequencies and shear strains. Frequency sweep tests were performed from 0.1 Hz to a maximum of 9.5 Hz at a shear strain of 0.1%, and strain sweep tests were carried out from 0.01% to 10% at 1 Hz. The effect of pre-compression of samples up to 10% axial strain was considered. The experimental measurements were fit to a Semi-Fractional Kelvin Voight (S-FKV) model. The model was then used to predict the stress relaxation in response to a step strain of 0.1%. The prediction was compared to experimental relaxation data for the porcine organ samples, and the results agreed to within 30%. In conclusion, this study measured the rheological properties of porcine organs and used a fractional viscoelastic model to describe the response in frequency and time domain
Cerebral magnetic resonance elastography in supranuclear palsy and idiopathic Parkinson's disease
Detection and discrimination of neurodegenerative Parkinson syndromes are challenging clinical tasks and the use of standard T1- and T2-weighted cerebral magnetic resonance (MR) imaging is limited to exclude symptomatic Parkinsonism. We used a quantitative structural MR-based technique, MR-elastography (MRE), to assess viscoelastic properties of the brain, providing insights into altered tissue architecture in neurodegenerative diseases on a macroscopic level. We measured single-slice multifrequency MRE (MMRE) and three-dimensional MRE (3DMRE) in two neurodegenerative disorders with overlapping clinical presentation but different neuropathology — progressive supranuclear palsy (PSP: N = 16) and idiopathic Parkinson's disease (PD: N = 18) as well as in controls (N = 18). In PSP, both MMRE (Δμ = − 28.8%, Δα = − 4.9%) and 3DMRE (Δ|G*|: − 10.6%, Δφ: − 34.6%) were significantly reduced compared to controls, with a pronounced reduction within the lentiform nucleus (Δμ = − 34.6%, Δα = − 8.1%; Δ|G*|: − 7.8%, Δφ: − 44.8%). MRE in PD showed a comparable pattern, but overall reduction in brain elasticity was less severe reaching significance only in the lentiform nucleus (Δμ n.s., Δα = − 7.4%; Δ|G*|: − 6.9%, Δφ: n.s.). Beyond that, patients showed a close negative correlation between MRE constants and clinical severity. Our data indicate that brain viscoelasticity in PSP and PD is differently affected by the underlying neurodegeneration; whereas in PSP all MRE constants are reduced and changes in brain softness (reduced μ and |G*|) predominate those of viscosity (α and φ) in PD
COGNITIVE-ENHANCING PROPERTIES OF MORINDA LUCIDA (RUBIACEAE) AND PELTOPHORUM PTEROCARPUM (FABACEAE) IN SCOPOLAMINE-INDUCED AMNESIC MICE
Background: Cognitive disorders associated with aging have been successfully managed by African traditional
medical practitioners using various plants. This study evaluated the cognitive enhancing potentials of Morinda lucida
(L) Rubiaceae and Peltophorum pterocarpum (DC) ex. K Heyne in scopolamine induced amnesic animals.
Materials and Methods: The anti-amnesic activity of the ethyl acetate extracts of Morinda lucida and Peltophorum
pterocarpum at doses of 4 mg/kg, 6 mg/kg and 8 mg/kg were assessed in scopolamine induced amnesic mice using
Morris water maze test model. Effect of the extracts on the histology of the hippocampus was also evaluated.
Results: The ethyl acetate extract of Morinda lucida and Peltophorum pterocarpum ameliorated scopolamine induced
memory deficit in the animals under study. There was no effect of the extract on the histology of the hippocampus.
However, there was an increase in the density of cells in the hippocampus of treated group as compared to the
untreated.
Conclusion: Morinda lucida and Peltophorum pterocarpum showed considerable enhancement of cognition in
scopolamine induced amnesic mice
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