Taurine can Decrease Phosphorylated Tau Protein Levels in Alzheimer's Model Rats' Brains.

Background Microtubule formation is a dynamic process and Tau proteins promote the assembly of tubulin monomers into microtubules. Hyperphosphorylation of some amino acids in tau proteins causes neuron starvation and finally cell death. Taurine is found in the brain and has neuroprotective effects. Objective Since the protective and therapeutic effects of Taurine on phosphorylated tau proteins level in the cerebellum and prefrontal cortex of rats induced by scopolamine have not been studied, we examined these effects. Method Adult male Wistar rats were randomly distributed into nine groups. For two weeks, Taurine-treated rats received different doses of Taurine (25, 50, and 100 mg/kg/ day) before or after scopolamine injection. The phosphorylated tau protein level in the cerebellum and prefrontal cortex was determined by the enzyme-linked immunosorbent assay (ELISA) technique. Result Pretreatment with three doses of Taurine significantly decreased the phosphorylated tau protein level that increased by scopolamine in the prefrontal cortex (p < 0.001), as well as the cerebellum (p < 0.001). Moreover, high-dose administration of Taurine (100 mg/kg/day) after scopolamine injection significantly decreased phosphorylated tau protein level in the cerebellum (p < 0.01), as well as the prefrontal cortex (p < 0.05). However, there was not any significant change in the level of phosphorylated tau protein after Taurine treatment (25 and 50 mg/kg/day) in the cerebellum and prefrontal cortex. Conclusion It can be concluded that Taurine could attenuate the increase in phosphorylated tau protein induced by scopolamine in the brain of rats and usage of Taurine as a pretreatment complement could be more useful in the protection of neurons.

Adsorption of hazardous atoms on the surface of TON zeolite and bilayer silica: a DFT study.

In the present study, the adsorption of two types of hazardous atoms including arsenic and lead with TON zeolite and bilayer silica (2D-SiO2) have been investigated by employing Ab initio-based density functional theory (DFT) calculations. To reach a full structural optimization and the most stable configuration, four sites were considered for TON zeolite as well as five sites for 2D-SiO2, and adsorption energy along with equilibrium geometry was determined. The adsorption energies of arsenic atom on the surface of 2D-SiO2 absorbents and TON zeolite have obtained equal to and - 1.25 eV and - 2.76 eV, respectively, which both of them are chemisorption type. We also found that the adsorption of lead on the surface of 2D-SiO2 was physisorption type with the adsorption energy accounting for - 0.13 eV, while the adsorption energy between lead and TON was calculated equal to - 2.32 eV which was chemisorption type. Furthermore, our results demonstrate that the TON zeolite was more capable of adsorbing hazardous atoms compared with 2D-SiO2 due to having greater adsorption energy. The adsorption of arsenic on the 2D-SiO2 and TON adsorbents is also stronger than those of lead atom. Furthermore, we modeled and considered graphene, as a common adsorbent nanostructure, to compare and validate the accuracy of our simulations and obtained results. Finally, the electronic density of states (DOS) calculations and charge analysis were done by the use of Mulliken method, and the results confirmed those results that had already been obtained from adsorption energies. Graphical abstract.

Effects of hCG on reduced numbers of hCG receptors in the prefrontal cortex and cerebellum of rat models of Alzheimer's disease.

Age-associated changes in the levels of luteinizing hormone and human chorionic gonadotropin (hCG) are potential risk factors for Alzheimer's disease (AD); hCG concentration is related to the incidence of AD. The highest density of hCG receptors is in zones of the brain that are vulnerable to AD and streptozotocin (STZ) can decrease the density of this receptor. We investigated the effects of different doses of hCG on hCG receptor density in the prefrontal cortex and cerebellum in a rat model of STZ-induced AD. AD was induced by intracerebroventricular injection of 3 mg/kg STZ. The resulting AD rats were treated for 3 days with 50, 100 or 200 IU/200 µl hCG, or with saline as a control. Sections of prefrontal cortex and cerebellum were stained immunohistochemically and hCG receptor-immunoreactive (ir) neurons were counted. STZ injected into the lateral ventricles of rat brains reduced the density of hCG receptor-ir neurons in the prefrontal cortex and cerebellum. hCG administration resulted in a significant dose-dependent increase in the number of hCG receptor-ir neurons in the prefrontal cortex and cerebellum. The maximum increase in the number of receptors occurred following the 200 IU dose of hCG. Administration of hCG ameliorated the lowered density of hCG receptor-ir neurons in the cerebellum and prefrontal cortex in STZ-induced AD rats.

Design, fabrication and structural optimization of tubular carbon/Kevlar®/PMMA/graphene nanoplate composite for bone fixation prosthesis.

The present work investigates the mechanical properties of tubular carbon/Kevlar® composite coated with poly(methyl methacrylate)/graphene nanoplates as used in the internal fixation of bones. Carbon fibers are good candidates for developing high-strength biomaterials and due to better stress transfer and electrical properties, they can enhance tissue formation. In order to improve carbon brittleness, ductile Kevlar® was added to the composite. The tubular carbon/Kevlar® composites have been prepared with tailorable braiding technology by changing the fiber pattern and angle in the composite structure and the number of composite layers. Fuzzy analyses are used for optimizing the tailorable parameters of 80 prepared samples and then mechanical properties of selected samples are discussed from the viewpoint of mechanical properties required for a bone fixation device. Experimental results showed that with optimizing braiding parameters the desired composite structure with mechanical properties close to bone properties could be produced. Results showed that carbon/Kevlar® braid's physical properties, fiber composite distribution and diameter uniformity resulted in matrix uniformity, which enhanced strength and modulus due to better ability for distributing stress on the composite. Finally, as graphene nanoplates demonstrated their potential properties to improve wound healing intended for bone replacement, so reinforcing the PMMA matrix with graphene nanoplates enhanced the composite quality, for use as an implant.

α2-Adrenoceptor-ir neurons' density changes after single dose of clonidine and yohimbine administration in the hippocampus of male rat.

OBJECTIVE: Despite the important role of α2-adrenoceptors in pain modulation processes, the impact of administration of α2-adrenoceptor agonist and antagonist on the density of hippocampal α2-adrenoceptor-immunoreactive neurons has not been investigated. Therefore, we aimed to determine the effect of single doses of clonidine and yohimbine on the density of α2-adrenoceptor-immunoreactive neurons in rat hippocampus. MATERIALS AND METHODS: Adult male Wistar rats received a single dose of clonidine (0.7 mg/kg) alone or 5 min after intraperitoneal (1 mg/kg) and/or intracerebroventricular (5 µg/kg) injection of yohimbine. After histological processing, neurons with α2-adrenoceptor immunoreactivity were identified and counted through immunohistochemical analysis of hippocampal regions. RESULTS: Clonidine slightly increased the number of α2-adrenoceptor-immunoreactive neurons in the hippocampal subregions compared with the normal saline group. Intraperitoneal injection of yohimbine followed by injection of clonidine significantly increased the number of α2-adrenoceptor-immunoreactive neurons in subregions cornu ammonis 1 (CA1) and cornu ammonis 3 (CA3). Intracerebroventricular injection of yohimbine after injection of clonidine significantly reduced the number of α2-adrenoceptor-immunoreactive neurons in all hippocampal subregions. CONCLUSION: The present study demonstrates that intraperitoneal administration of α2-adrenoceptor agonist clonidine increases the density of α2-adrenoceptor-immunoreactive neurons in rat hippocampus, while intracerebroventricular injection of yohimbine decreases the density of these neurons.

Computational studies on the interactions of glycine amino acid with graphene, h-BN and h-SiC monolayers.

In the present work, the adsorption of glycine amino acid and its zwitterionic form onto three different hexagonal sheets, namely graphene, boron-nitride (h-BN) and silicon carbide (h-SiC), has been investigated within the framework of Density Functional Theory (DFT) calculations. The energetics and geometrical parameters of the considered systems have been explored at the GGA-PBE level in combination with Grimme's empirical dispersion corrections with Becke-Johnson damping, the DFT-D3(BJ) method. Based on the obtained results, we found that both the glycine molecule and its zwitterionic conformation tend to be chemisorbed onto the surface of h-SiC (Eads ranges from -1.01 to -1.319 eV) while the types of interactions are recognized to be of non-covalent nature for the case of graphene (Eads ranges from -0.121 to -0.345 eV) and h-BN (Eads ranges from -0.103 eV to -0.325 eV) systems. Moreover, the empirical dispersion corrections applied in these calculations significantly improved the results and confirmed the crucial role of dispersion corrections in obtaining reliable geometries and adsorption energies. Our findings revealed that the electronic properties of the considered systems did not change during the adsorption process and these monolayers preserve their inherent electronic properties as they interact with the glycine molecule. Using the SMD implicit solvation model, the effect of solvation has also been evaluated by re-optimizing the structures within a medium with a dielectric constant of 78.39 (liquid water) and it has been shown that the strength of the interaction between the glycine conformers and hexagonal sheets has decreased. The accuracy of the obtained values has been evaluated by some benchmark calculations at the hybrid PW6B95 level of theory and reasonable consistency is found between the results of the PBE-D3 method and our benchmark system. In summary, h-SiC exhibited the highest affinity toward glycine conformers and gained an important edge over other monolayers. Our findings would actively encourage experimentalists to explore the potential applications of these materials in drug delivery, biofunctionalization of nanostructured monolayers as well as electronic and nanosensor devices.

Levodopa medication improves incidental sequence learning in Parkinson's disease.

Empirical evidence suggests that levodopa medication used to treat the motor symptoms of Parkinson's disease (PD) may either improve, impair or not affect specific cognitive processes. This evidence led to the 'dopamine overdose' hypothesis that levodopa medication impairs performance on cognitive tasks if they recruit fronto-striatal circuits which are not yet dopamine-depleted in early PD and as a result the medication leads to an excess of dopamine. This hypothesis has been supported for various learning tasks including conditional associative learning, reversal learning, classification learning and intentional deterministic sequence learning, on all of which PD patients demonstrated significantly worse performance when tested on relative to off dopamine medication. Incidental sequence learning is impaired in PD, but how such learning is affected by dopaminergic therapy remains undetermined. The aim of the current study was to investigate the effect of dopaminergic medication on incidental sequence learning in PD. We used a probabilistic serial reaction time task (SRTT), a sequence learning paradigm considered to make the sequence less apparent and more likely to be learned incidentally rather than intentionally. We compared learning by the same group of PD patients (n=15) on two separate occasions following oral administration of levodopa medication (on state) and after overnight withdrawal of medication (off state). Our results demonstrate for the first time that levodopa medication enhances incidental learning of a probabilistic sequence on the serial reaction time task in PD. However, neither group significantly differed from performance of a control group without a neurological disease, which indicates the importance of within group comparisons for identifying deficits. Levodopa medication enhanced incidental learning by patients with PD on a probabilistic sequence learning paradigm even though the patients were not aware of the existence of the sequence or their acquired knowledge. The results suggest a role in acquiring incidental motor sequence learning for dorsal striatal areas strongly affected by dopamine depletion in early PD.

Impaired probabilistic classification learning with feedback in patients with major depression.

BACKGROUND: The function of basal ganglia (BG) in the pathophysiology of major depression (MD) is still unclear. Recent research found changes in BG regarding size, structure and cerebral perfusion in patients with MD. Neuroimaging shows recruitment of the striatum during feedback (FB) based incidental learning of probabilistic classification learning, while the medial temporal lobe (MTL) is associated with paired associate (PA) based incidental learning. The purpose of this study was to evaluate whether FB-based incidental learning is affected in MD. METHODS: The FB and PA versions of the weather prediction task (WPT), a task of incidental probabilistic classification learning, were completed by patients with MD (n=44) and healthy controls (n=44). In FB-learning the participants received either a "thumbs-up" or "thumbs-down" message according to their right or wrong classification of cards to a certain kind of weather (either rainy or fine), while in PA learning no classification was required. Severity of MD was rated on the Beck Depression Inventory and Hamilton Rating Scale for depression. RESULTS: Patients with MD were selectively impaired on the FB task relative to controls (p<0.05), while no significant difference was found for PA learning between the two groups. Furthermore, there were no significant differences between FB and PA-learning within the patient and control groups. CONCLUSION: Our results indicate a distinct impairment on the FB-based version of the weather prediction task. These findings implicate disturbed reinforcement learning in this group of patients.

In Parkinson's disease pallidal deep brain stimulation speeds up response initiation but has no effect on reactive inhibition.

The fronto-striatal circuits are considered to mediate inhibitory control over action. The aim of this study was to investigate the contribution of the internal segment of the pallidum (GPi), one of the final output pathways from the basal ganglia to the cortex, in inhibition. We examined the effect of deep brain stimulation (DBS) of the GPi (GPi-DBS) in patients with Parkinson's disease who performed a conditional stop signal task, with DBS on and off. Modulation of GPi activity was associated with significantly faster Go reaction times with DBS on than off, but stop signal reaction times were not altered. Application of the drift diffusion model indicated that GPi-DBS was associated with significantly lower response thresholds compared to GPi-DBS off. However, the drift rate was significantly lower than healthy controls with both GPi-DBS on and off. These results suggest that the GPi plays a crucial role in the 'Go' pathway, perhaps facilitating reaching the required threshold to initiate actions. However, GPi-DBS does not alter the functioning of the indirect 'NoGo' pathway, and other basal ganglia nuclei, such as the STN, may play a greater role in reactive response inhibition and conflict resolution.

The effect of MDMA-induced anxiety on neuronal apoptosis in adult male rats' hippocampus.

Ecstasy or MDMA as a psychoactive drug and hallucinogen is considered one of the most commonly used drugs in the world. This psychotropic substance is discussed both as sexually stimulating and reducing fear and anxiety. Amphetamines also destroy neurons in some brain areas. The aim of this study was to investigate the effects of MDMA on anxiety and apoptosis of hippocampal neurons. Forty-two male Wistar rats of mean weight 200-220 g were used and distributed into six groups [control, control-saline, and experimental groups (1.25, 2.5, 5, 10 mg/kg)]. Rats in experimental groups received MDMA at different doses for seven days by intraperitoneal injection and the control-saline group received saline (1 ml/kg); anxiety was then investigated by plus-maze test. Forty-eight hours after behavioural testing brains were taken from animals and fixed, and after tissue processing, slices were stained with TUNEL kit for apoptotic cells. The area densities of apoptotic neurons were measured throughout the hippocampus and compared in all groups (P < 0.05). Physiological studies showed that 1.25 mg/kg and 2.5 mg/kg doses caused anti-anxiety behaviour and 5 and 10 mg/kg doses of MDMA caused anxietylike behaviour. Moreover, our histological study showed that ecstasy increased apoptotic cell numbers and the highest increase was observed with the 10 mg/kg dose of MDMA. We concluded that MDMA can cause different responses of anxiety-like behaviour in different doses. This phenomenon causes a different ratio of apoptosis in hippocampal formation. Reduction of anxiety-like behaviour induced by the 2.5 mg/kg dose of MDMA can control apoptosis.

Female rat hippocampal cell density after conditioned place preference.

The hippocampus is important for learning tasks, such as conditioned place preference (CPP), which is widely used as a model for studying the reinforcing effects of drugs with dependence liability. Long-term opiate use may produce maladaptive plasticity in the brain structures involved in learning and memory, such as the hippocampus. We investigated the phenomenon of conditioning with morphine on the cell density of female rat hippocampus. Forty-eight female Wistar rats weighing on average 200-250 g were used. Rats were distributed into eight groups. Experimental groups received morphine daily (three days) at different doses (2.5, 5, 7.5 mg/kg) and the control-saline group received normal saline (1 ml/kg), and then the CPP test was performed. Three sham groups received only different doses (2.5, 5, 7.5 mg/kg) of morphine without CPP test. Forty-eight hours after behavioural testing animals were decapitated under chloroform anaesthesia and their brains were fixed, and after tissue processing, slices were stained with cresyl violet for neurons and phosphotungstic acid haematoxylin for astrocytes. The maximum response was obtained with 5 mg/kg of morphine. The density of neurons in CA1 and CA3 areas of hippocampus after injection of morphine and CPP was decreased. The number of astrocytes in different areas of hippocampus was increased after injection of morphine and CPP. It seems that the effective dose was 5 mg/kg, as it led to the CPP. We concluded that both injection of mor phine and CPP can decrease the density of neurons and also increase the number of astrocytes in the rat hippocampus.

Scopolamine reduces the density of M1 muscarinic neurons in rats' hippocampus / La escopolamina reduce la densidad de las neuronas muscarínicas M1 en el hipocampo de ratas

Cholinergic system in CNS is involved in learning and memory. Scopolamine as muscarinic acetylcholine receptor antagonist is used for creation of memory impairment. The purpose of this study is evaluation of scopolamine-based amnesia on memory retention and the effect of this phenomenon on the number of neurons contains M1-receptors in the male Wistar rats hippocampal regions. Thirty-five male Wistar rats (200+/-20 g) were distributed randomly into five groups. Control group (intact samples) and 3 experimental groups with sham group (saline) were tested by the method of passive avoidance (shuttle box) in doses of 0.2, 0.5 and 1 mg/kg (intraperitoneally) as a single dose. After one week, memory test was taken from the rats. Finally, brains dissected from sacrificed rats, and then processed tissues were stained with antibody against M1 receptors (Immunohistochemistry technique) followed by counting of hippocampal CA1, CA3 and DG regions. Our results showed significant decrease in neurons contains M1-receptors in all area of hippocampus. We found that the less number of M1-neurons showed in 1 mg/kg dose of scopolamine. We concluded that scopolamine as muscarinic acetylcholine receptor antagonist can reduce dose-dependently the density of M1-neurons in all areas of hippocampus.

El sistema colinérgico en el SNC está implicado en el aprendizaje y la memoria. La escopolamina como receptor antagonista de acetilcolina muscarínico es utilizada para la creación del deterioro de la memoria. El propósito de este estudio es la evaluación de la amnesia basada en escopolamina sobre la retención de memoria y el efecto de este fenómeno en la cantidad de neuronas en receptores M1 en regiones del hipocampo en ratas macho Wistar. Se distribuyeron al azar, 35 ratas macho Wistar (200+/-20 g) en cinco grupos. El grupo de control (muestras intactas) y 3 grupos experimentales con grupo de tratamiento simulado (solución salina) analizadas por método de evasión pasiva (caja de transporte) en dosis de 0,2; 0,5 y 1 mg/kg (por vía intraperitoneal) como dosis única. Al término de una semana se realizó prueba de memoria de las ratas. Por último, los cerebros diseccionados de las ratas sacrificadas y los tejidos procesados fueron teñidos con anticuerpos contra los receptores M1 (técnica inmunohistoquímica), seguido por el recuento de regiones CA1, CA3 y DG del hipocampo. Nuestros resultados mostraron una disminución significativa en las neuronas con receptores M1 en toda el área del hipocampo. Se encontró que el número menor de neuronas M1, y fue demostrado en 1 mg/kg de dosis de escopolamina. Llegamos a la conclusión de que la escopolamina como antagonista del receptor de acetilcolina muscarínico puede, dependiendo de la dosis, reducir la densidad de neuronas M1 en todas las áreas del hipocampo.

Effect of Gingko biloba extract on scopolamine-induced apoptosis in the hippocampus of rats.

Apoptosis, known as programmed cell death, plays a crucial role in normal development and tissue homeostasis. Apoptosis is also involved in neurodegenerative diseases such as Alzheimer's disease. Amnesia refers to the loss of memory and can also be a warning sign of neurodegenerative diseases. The antioxidant properties of Ginkgo biloba extract was known previously. Therefore, the aim of this study was to examine the effects of Ginkgo biloba extract on the rat's hippocampal apoptotic neurons number after Scopolamine based amnesia. Thirty-six adult male Wistar rats were used. Rats were randomly divided into control, sham, protective and treatment groups. The rats in the sham group received only scopolamine hydrobromide (3 mg/kg) intraperitoneally. The rats in the protective and treatment groups received Ginkgo biloba extract (40, 80 mg/kg) for 7 days intraperitoneally before/after scopolamine injection. Then 48 h after the last injection, the brains of rats were withdrawn and fixed with paraformaldehyde, and then, after histological processing, the slices were stained with the TUNEL kit for apoptotic neurons. Data were compared by the ANOVA Post Hoc Tukey test; P < 0.05 was considered significant. Our results showed that Scopolamine (in the sham group) increased significantly the number of apoptotic neurons in all areas of the hippocampus compared with the control. Whereas, Ginkgo biloba extract reduce the neuronal apoptosis in the hippocampus before and/or after encounter with scopolamine. We concluded that pretreatment and treatment injection of Ginkgo biloba extract can have a protective effect for neurons and it can limit apoptosis in all area of the hippocampus.

Stimulation of the pre-SMA influences cerebral blood flow in frontal areas involved with inhibitory control of action.

Selection of the most appropriate response necessitates inhibition of competing or prepotent responses. It is important to characterize which cortical areas are relevant to achieve response inhibition. Using the stop signal task, previous imaging studies revealed consistent activation in the right pre-supplementary motor area (pre-SMA). However, imaging alone suffers from the limitation that it can only provide neuronal correlates and cannot establish causality between brain activation and behavior. Repetitive transcranial magnetic stimulation (rTMS) can be used to temporarily interfere with the function of a cortical area considered to play a specific role in the behavior. Thus, we combined rTMS with H(2)(15)O positron emission tomography (PET) scans during the stop signal task, to test whether rTMS-induced changes in excitability of the right pre-SMA influenced response inhibition. We found that rTMS over the pre-SMA increased the efficiency of the inhibitory control over prepotent ongoing responses. A significant interaction was present in the left inferior frontal gyrus (IFG) along with an increase in regional cerebral blood flow (rCBF) in the left pre-SMA, left IFG, right premotor and right inferior parietal cortex. These areas best fitted the path analysis model in the effective connectivity model. The results of this study suggest that stimulation of the right pre-SMA, by interfering with its activity, may have a significant impact on response inhibition.

Gender differences in quality of life following subthalamic stimulation for Parkinson's disease.

OBJECTIVES: Surveys of subthalamic nucleus (STN) deep brain stimulation (DBS) for Parkinson's disease (PD) have shown that this procedure is roughly twice more common in men than in women. Here, we investigate possible differences between women and men undergoing STN DBS, with respect to health-related quality of life. MATERIALS AND METHODS: Forty-nine consecutive patients (18 women) received STN DBS. The impact of PD and its surgical treatment was compared between women and men, before and at mean of 19 ± 11 months after surgery, using the Unified Parkinson Disease Rating Scale (UPDRS) and the Parkinson's Disease Questionnaire-39 (PDQ-39). RESULTS: Duration of disease at surgery and off-medication scores of the motor part of the UPDRS were similar in women and men. At baseline, women had lower doses of dopaminergic medication than men, experienced more disability due to dyskinesias, had more sensory symptoms and perceived more difficulties in mobility. Following DBS, both men and women showed equal and significant (P < 0.001) improvement in off-medication scores on the UPDRS III. On the PDQ-39, women expressed improvement in ADL to a greater extent than men. Moreover, women but not men showed a positive effect on mobility, stigma and cognition as well as on the summary score of PDQ-39. CONCLUSIONS: Although STN DBS results in equal degree of motor improvement between women and men, health-related quality of life seems to improve to a greater extent in women.

Effect of scopolamine-based amnesia on the number of astrocytes in the rat's hippocampus / Efecto de la amnesia inducida por escopolamina sobre el número de astrocitos en el hipocampo de ratas

As neuron­astrocyte interactions play a crucial role in the adult brain, it is thought that astrocytes support learning and memory through specific mechanisms. In this study, the effect of scopolamine based amnesia on the number of astrocytes in rats' hippocampus was studied. Adult male albino Wistar rats were bilaterally cannulated into the CA1 region and animals received saline or different doses of scopolamine (0.5, 1 and 2 mg/ rat, intra - CA1), immediately after training. Then all the rats were sacrificed and coronal sections were taken from the dorsal hippocampal formation of the right cerebral hemispheres and stained with PTAH. The area densities of the astrocytes in dentate gyrus were measured and compared in the all groups (p < 0.05). Data showed that post-training scopolamine (0.5, 1 and 2 ug/rat, intra-CA1) dose-dependently reduced the step-through latency in the inhibitory avoidance task, showing scopolamine-induced amnesia. Also we found different response of astrocytes in different subfields of hippocampal formation. In dentate gyrus the number of astrocytes was increased, but in other areas scopolamine can decreased the density of astrocytes. We concluded that scopolamine can cause amnesia and this phenomenon can have an effect on astrocyte numbers in the rats hippocampal formation.

Las interacciones neuronas-astrocitos desempeñan un papel crucial en el cerebro adulto, y se cree que los astrocitos apoyan el aprendizaje y la memoria a través de mecanismos específicos. Fue estudiado el efecto de amnesia inducida por escopolamina en el número de astrocitos del hipocampo de ratas. Ratas Wistar albinas macho adultas fueron canuladas bilateralmente en la región CA1 recibiendo solución salina o diferentes dosis de escopolamina (0,5, 1 y 2mg/rata, intra - CA1), inmediatamente después del entrenamiento. Luego, todas las ratas se sacrificaron y se tomaron secciones coronales de la formación del hipocampo dorsal del hemisferio cerebral derecho y se tiñeron con PTAH. Las densidades de área de los astrocitos en el giro dentado fueron medidas y comparadas en todos los grupos (p <0,05). Los datos mostraron que la escopolamina (0,5, 1 y 2 mg / rata, intra-CA1) dosis-dependiente post-entrenamiento redujo el paso de latencia de la tarea de evitación inhibitoria, mostrando amnesia inducida por escopolamina. También encontramos diferentes respuestas de los astrocitos en los distintos subcampos de la formación hipocampal. En el giro dentado, el número de astrocitos se incrementó, pero en otras áreas la escopolamina pudo disminuir la densidad de los astrocitos. Se concluye que la escopolamina puede causar amnesia y este fenómeno puede afectar el número astrocitos en la formación hipocampal de ratas.

Preparation and characterization of agarose-nickel nanoporous composite particles customized for liquid expanded bed adsorption.

Agarose-nickel nanoporous composite matrices with a series of densities, named Ag-Ni, were prepared herein for expanded bed adsorption of nanobioproduct/bioproduct by a water-in-oil emulsification method. The optical microscope (OM), scanning electronic microscope (SEM) and particle size analyzer (PSA) were utilized in order to characterize the structure and morphology of the agarose-nickel composite. The results indicated that the matrices prepared had a spherical appearance, appropriate wet density of 1.73-2.56 g/ml, water content of 32.2-58.5% and porosity of 79.4-96.37% and pore size of about 100-150 nm. All the Ag-Ni beads follow logarithmic normal size distribution with the range of 60-230 µm and average diameter of 133.68-148.4 µm. One of the useful properties of the Ag-Ni particles is the high wet density up to 2.56 g/ml, which shows a potential for the operation in an expanded bed at high flow rate. The impact of nickel powder addition on the physical and hydrodynamic properties was also investigated. In addition, the fluidization behavior of the Ag-Ni particles under various conditions was characterized by the measurement of bed expansion and axial dispersion coefficients for the liquid phase when operated in a standard fluidized bed contactor. It was observed that the expansion factors were decreased with the increasing matrix density under the same velocity. The bed expansion and fluid velocity were correlated with Richardson-Zaki equation for all particles prepared and the correlation parameters (the terminal settling velocity U(t) and expansion index n) were investigated. Using measurements of residence time distributions, hydrodynamic properties in the expanded beds were investigated and were compared with reported matrices in other literatures. In addition, the impact of the flow velocity, bed expansion degree and density of adsorbent on hydrodynamic properties in the expanded beds were investigated. The results indicated that the expansion factor showed little effect on the hydrodynamic properties while the fluid velocity was the most essential factor on this regard. Furthermore, the results indicated that the heavy matrices of Ag-Ni-3, Ag-Ni-4 and Ag-Ni-5, were more suited for high operation fluid velocity. In addition, even the light matrices, i.e. Ag-Ni-1 and Ag-Ni-2, seem to be superior to other matrices in hydrodynamic properties, which made them promising adsorbents for further use in EBA processes.

Gamma radiation-induced impairment of hippocampal neurogenesis, comparison of single and fractionated dose regimens / Deterioro de la neurogénesis en el hipocampo inducida por radiación gamma, comparación de los regímenes de dosis única y fraccionada

Radiation therapy of the brain is associated with many consequences, including cognitive disorders. Pathogenesis of radiation induced cognitive disorder is not clear, but reduction of neurogenesis in hippocampus may be an underlying reason. 24 adult male rats entered to study. Radiation absorbed dose to midbrain was 10 Gy, delivered by routine cobalt radiotherapy machine which its output was measured 115.24 cGy/min. The rats were divided in four groups of sixes, including groups of control, single fraction 10 Gy, fractionated 10 Gy and finally anaesthesia sham group. Number of pyramidal nerve cells was counted in two regions of hippocampus formation (CA1 and CA3). The radiation could reduce the number of cells in two regions of hippocampus significantly (p=0.000). It seems fractionated 10 Gy irradiation to more efficient than single fraction, while role of anaesthesia drug should be cautiously assessed. Moreover the rate of neurogenesis reduction was determined the same in these regions of hippocampus meaning the same radiosensitivity of cells.

La terapia de radiación cerebral está asociada con muchas consecuencias, incluyendo los trastornos cognitivos. La patogénesis del trastorno cognitivo inducido por la radiación no está claro, pero la reducción de la neurogénesis en el hipocampo puede ser una razón subyacente. Fueron etudiadas 24 ratas macho adultas. La dosis de radiación absorbida en el mesencéfalo fue de 10 Gy, proveniente de una máquina de radioterapia de cobalto con una salida de 115,24 cGy/min. Las ratas fueron divididas en cuatro grupos de seis ratas cada uno, incluyendo un grupo control, fracción única de 10 Gy, fraccionada de 10 Gy y finalmente el grupo de anestesia simulado. El número de células nerviosas piramidales se contó en dos regiones de la formación del hipocampo (CA1 y CA3). La radiación podría reducir significativamente (p = 0,000) el número de células en dos regiones del hipocampo . Al parecer, la radiacioón fraccionada de 10 Gy es más eficiente que la fracción única, mientras que el rol de la anestesia debe ser cuidadosamente evaluado. Por otra parte la tasa de reducción de la neurogénesis fue observada en las mismas regiones del hipocampo es decir, con la misma radiosensibilidad de las células.

On the nature of fear of falling in Parkinson's disease.

In the elderly, fear of falling (FoF) can lead to activity restriction and affect quality of life (QoL). Our aim was to identify the characteristics of FoF in Parkinson's disease and assess its impact on QoL. We assessed FoF in 130 patients with Parkinson's disease (PD) on scales measuring perceived self-efficacy in performing a range of activities (FES), perceived consequences of falling (CoF), and activity avoidance (SAFFE). A significant difference was found in FoF between PD patients who had previously fallen and those who had not and between frequent and infrequent fallers. Patient-rated disability significantly influenced FoF. Difficulty in rising from a chair, difficulty turning, start hesitation, festination, loss of balance, and shuffling were the specific mobility problems which were associated with greater FoF in PD. Disability was the main predictor of FoF, additionally depression predicted perceived consequences of falling, while anxiety predicted activity avoidance. The FoF measures explained 65% of the variance of QoL in PD, highlighting the clinical importance of FoF. These results have implications for the clinical management of FoF in PD.