Assessment of the hemagglutinating activity of the Porcine orthorubulavirus.

Blue eye disease (BED) in pigs is caused by Porcine orthorubulavirus (PRV) of the Paramyxoviridae family. It is an endemic disease in swine production in the central region of Mexico and causes nervous signs and high mortality in suckling pigs, pneumonia in growing pigs, orchitis in boars and mummification during gestation. PRV hemagglutinates most red blood cells (RBCs) of domestic species. For serological diagnosis, the hemagglutination inhibition test is used, and in this test, guinea pig, bovine and chicken RBCs have been commonly used. In this investigation, hemagglutination with PRV was evaluated using the RBCs of seven domestic species (chicken, bovine, horse, pig, dog, guinea pig and rabbit). In the hemagglutination test, the following parameters were evaluated: temperature (25 °C and 37 °C), bottoms of the wells (V and U), erythrocyte concentration (0.5%, 0.75%, and 1%), and reading time (15, 30, 45, 60 and 90 min). Significant differences (P < 0.001) were found in most of the evaluated treatments. The best hemagglutination results were obtained with chicken, bovine and horse RBCs. The hemagglutination titer is higher (2 dilutions) when using chicken RBCs than when using bovine or horse RBCs. If chicken RBCs are used in the inhibition of hemagglutination, the test will be more sensitive, while it is more specific when bovine or horse RBCs are used. The hemagglutination readings are imprecise when using RBCs from dogs, pigs, guinea pigs and rabbits. RBCs from these species should not be used for the diagnosis or investigation of PRV.

Clothianidin and Thiacloprid Mixture Administration Induces Degenerative Damage in the Dentate Gyrus and Alteration in Short-Term Memory in Rats.

Neonicotinoids are pesticides that act as agonists of nicotinic receptors for acetylcholine in insects' central nervous system (CNS). Chronic exposure to neonicotinoids in humans is related to autism, memory loss, and finger tremor. In this article, we evaluate the effect of subchronic oral administration of two neonicotinoids in the same mixture: clothianidin and thiacloprid. Decreasing doses of both pesticides were administered to rats starting from the lethal dose 50 (LD50) reported by the manufacturer. Our results indicate that the administration of three doses of decreasing amounts of LD50 (5/10, 4/10, and 3/10 LD50) resulted in 100% death in all cases. Ten administration times of 2/10 LD50 of the mixture caused only 20% of death cases after twenty-seven days, which was determined as a subchronic administration scheme. The animals administered 2/10 LD50 showed behavioral alterations after the first and second administration. Electrographic studies showed abnormal discharge patterns in the CNS. 72 h after the tenth dose, learning and memory tests were performed in the Morris water maze. Our results revealed significant decreases in permanence at the quadrant and the number of crosses (P=0.0447, P=0.0193, respectively), which represent alterations in the short-term memory test, but there were no significant changes in a long-term memory test. Likewise, the brains of these animals showed tissue architecture loss, nucleosomal retraction, and a significant increase in the pycnosis of the granular neurons of the dentate gyrus analyzed at 72 h after the last dose (P=0.0125). Toxic effects and cognitive deterioration that have been found in communities living near contaminated areas are probably related to the agricultural use of neonicotinoids.

Inmunoexpresión de p53 y su relación con el grado de severidad en displasia epitelial oral / Immunoexpression of p53 and its relationship with the degree of severity in oral epithelial dysplasia

Introducción: La displasia epitelial oral (DEO) es la presencia de alteraciones celulares y tisulares, lo que puede significar una etapa anterior al desarrollo del cáncer. Múltiples marcadores han sido considerados para estimar su potencial neoplásico y evolución a carcinoma, incluyendo a la molécula p53, se considera como participe de diversos fenómenos de la homeostasis celular. Objetivo: Determinar la relación entre la inmunoexpresión de p53 DO-7 y PAb 240 con el grado de severidad de la displasia epitelial oral. Material y métodos: Se analizaron nueve muestras de DEO (tres para cada grado de severidad). La inmunoexpresión de p53 tipo silvestre (DO-7) y forma mutada (PAb 240), fue determinada a través de ensayo de inmunohistoquímica por peroxidasa. Se obtuvieron la media y desviación estándar y se realizó la prueba χ2 (p < 0.05). Resultados: La edad media fue de 65.7 ± 11.4 años, la zona anatómica con mayor presencia de DEO es el borde lateral de la lengua. Ocho de nueve muestras fueron positivas para DO-7 y solo dos para PAb 240. Conclusiones: Nuestros resultados indican que, aunque la expresión de p53 DO-7 podría estar relacionada parcialmente con la patogénesis de la displasia epitelial, no todas las displasias presentaron la forma mutada de p53 (PAb 240). Lo cual coincide con el comportamiento biológico incierto de las displasias al poder permanecer sin cambios, involucionar o transformarse

Introduction: Oral epithelial dysplasia (OED) is the presence of cellular and tissue alterations, which may mean a stage prior to the development of cancer. Multiple markers have been considered to estimate its pathogenic potential and evolution to neoplasms, including the p53 molecule, considered as participating in various phenomena of cellular homeostasis. Objective: To determine the relationship between the immunoexpression of p53 DO-7 and PAb 240 with the degree of severity of oral epithelial dysplasia. Material and methods: Nine OED samples were analyzed (three for each degree of severity). The immunoexpression of wild-type p53 (DO-7) and mutated form (PAb 240) was determined through a peroxidase immunohistochemical assay. The mean and standard deviation were obtained, and χ2 test (p < 0.05) were performed. Results: The mean age was 65.7 ± 11.4 years, with a greater presence of OED in the anatomical area of the lateral side of the tongue. Eight out of nine samples were positive for DO-7 and only two for PAb 240. Conclusions: Our results indicate that, although the expression of p53 DO-7 could be partially related to the pathogenesis of epithelial dysplasia, not all dysplasias presented the mutated form of p53 (PAb 240), which coincides that not all dysplasias have a potential for malignant transformation and that could be related to other oncogenic mechanisms (AU)

Could SARS-CoV-2 blocking of ACE2 in endothelial cells result in upregulation of CX3CL1, promoting thrombosis in COVID-19 patients?

SARS-CoV-2 is the causal agent of COVID-19 disease. Currently, infection with SARS-CoV-2 has been the cause of death of over 2.5 million people globally, and there is still no effective curative treatment. Clinically, the severe symptoms caused by COVID-19, in addition to pneumonia, are associated with the development of hyperinflammatory syndrome and thrombosis. It is urgent to expand our understanding of the molecular mechanisms involved in the pathophysiology of COVID-19. This article discusses the potential role that the chemokine CX3CL1 could have in the development of COVID-19-associated thrombosis. CX3CL1 is abundantly expressed by activated endothelium and is an important regulator of many aspects of endothelial function and dysfunction, including thrombosis. The generation of hypotheses about molecules that could be relevant in well-defined aspects of the pathophysiology of COVID-19 encourages the development of basic and clinical studies, that could help find effective and much needed treatments.

Gallic acid improves recognition memory and decreases oxidative-inflammatory damage in the rat hippocampus with metabolic syndrome.

Metabolic syndrome (MS) results from excessive consumption of high-calorie foods and sedentary lifestyles. Clinically, insulin resistance, abdominal obesity, hyperglycemia, dyslipidemia, and hypertension are observed. MS has been considered a risk factor in the development of dementia. In the brain, a metabolically impaired environment generates oxidative stress and excessive production of pro-inflammatory cytokines that deteriorate the morphology and neuronal function in the hippocampus, leading to cognitive impairment. Therapeutic alternatives suggest that phenolic compounds can be part of the treatment for neuropathies and metabolic diseases. In recent years, the use of Gallic Acid (GA) has demonstrated antioxidant and anti-inflammatory effects that contribute to neuroprotection and memory improvement in animal models. However, the effect of GA on hippocampal neurodegeneration and memory impairment under MS conditions is still unclear. In this work, we administered GA (20 mg/kg) for 60 days to rats with MS. The results show that GA treatment improved zoometric and biochemical parameters, as well as the recognition memory, in animals with MS. Additionally, GA administration increased hippocampal dendritic spines and decreased oxidative stress and inflammation. Our results show that GA treatment improves metabolism: reducing the oxidative and inflammatory environment that facilitates the recovery of the neuronal morphology in the hippocampus of rats with MS. Consequently, the recognition of objects by these animals, suggesting that GA could be used therapeutically in metabolic disorders that cause dementia.

Epicatechin Reduces Spatial Memory Deficit Caused by Amyloid-ß25⁻35 Toxicity Modifying the Heat Shock Proteins in the CA1 Region in the Hippocampus of Rats.

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by dementia and the aggregation of the amyloid beta peptide (Aß). Aß25-35 is the most neurotoxic sequence, whose mechanism is associated with the neuronal death in the Cornu Ammonis 1 (CA1) region of the hippocampus (Hp) and cognitive damage. Likewise, there are mechanisms of neuronal survival regulated by heat shock proteins (HSPs). Studies indicate that pharmacological treatment with flavonoids reduces the prevalence of AD, particularly epicatechin (EC), which shows better antioxidant activity. The aim of this work was to evaluate the effect of EC on neurotoxicity that causes Aß25-35 at the level of spatial memory as well as the relationship with immunoreactivity of HSPs in the CA1 region of the Hp of rats. Our results show that EC treatment reduces the deterioration of spatial memory induced by the Aß25-35, in addition to reducing oxidative stress and inflammation in the Hp of the animals treated with EC + Aß25-35. Likewise, the immunoreactivity to HSP-60, -70, and -90 is lower in the EC + Aß25-35 group compared to the Aß25-35 group, which coincides with a decrease of dead neurons in the CA1 region of the Hp. Our results suggest that EC reduces the neurotoxicity induced by Aß25-35, as well as the HSP-60, -70, and -90 immunoreactivity and neuronal death in the CA1 region of the Hp of rats injected with Aß25-35, which favors an improvement in the function of spatial memory.

Evaluación de la citotoxicidad de Biodentine, IRM y MTA en cultivos de fibroblastos del ligamento periodontal humano / An evaluation of the cytotoxicity of Biodentine, IRM and MTA in cultures of human periodontal ligament fibroblasts

Introducción: Los materiales para la obturación retrógrada son diversos. Actualmente, IRM y MTA son las alternativas clínicas más utilizadas, no obstante, es relativamente reciente la introducción de materiales a base de silicatos tricálcicos tal como Biodentine. Objetivo: Determinar la citotoxicidad de fibroblastos del ligamento periodontal humano expuestos a medios de cultivo condicionados con Biodentine, IRM y MTA. Material y métodos: 1 × 103 fibroblastos del ligamento periodontal humano fueron expuestos a medios DMEM/F12 condicionados con MTA, IRM y Biodentine en tres protocolos diferentes. Se realizó un ensayo de MTT para determinar la viabilidad celular a las cero, 24, 48, 72 horas, siete y 14 días. Se realizó una prueba ANOVA (p < 0.05). Resultados: En los tres protocolos con los diferentes medios de cultivo condicionados, la viabilidad de las células fue predominantemente proliferativa; sin embargo, las células expuestas a Biodentine mostraron una tendencia mayor que la MTA o la IRM. Conclusión: Las células expuestas a la Biodentine mostraron un comportamiento proliferativo a los 14 días de análisis. Se debe realizar más investigación a nivel in vivo y clínico para obtener más información sobre la conducta de estos materiales empleados para la obturación retrógrada (AU)

Introduction: The materials for retrograde filling are diverse. Currently, IRM and MTA are the most commonly used clinical alternatives, however, the introduction of materials based on tricalcium silicates such as Biodentine is relatively recent. Objective: To determine the cytotoxicity of human periodontal ligament fibroblasts exposed to culture media conditioned with Biodentine, IRM and MTA. Material and methods: 1 × 103 fibroblasts of the human periodontal ligament were exposed to DMEM/F12 media conditioned with MTA, IRM and Biodentine in 3 different protocols. An MTT assay was performed to determine cell viability at 0, 24, 48, 72 hours, seven and 14 days. An ANOVA test was performed (p < 0.05). Results: In the three protocols with the different conditioned culture media, the viability of the cells was predominantly proliferative, however, the cells exposed to Biodentine showed a higher tendency than the MTA or the IRM. Conclusion: The cells exposed to the Biodentine showed a proliferative behavior at 14 days of analysis. More research should be done at in vivo and clinical level to obtain more information about the behavior of these materials used for retrograde filling (AU)

Alzheimer's disease and metabolic syndrome: A link from oxidative stress and inflammation to neurodegeneration.

Alzheimer's disease (AD) is the most common cause of dementia and one of the most important causes of morbidity and mortality among the aging population. AD diagnosis is made post-mortem, and the two pathologic hallmarks, particularly evident in the end stages of the illness, are amyloid plaques and neurofibrillary tangles. Currently, there is no curative treatment for AD. Additionally, there is a strong relation between oxidative stress, metabolic syndrome, and AD. The high levels of circulating lipids and glucose imbalances amplify lipid peroxidation that gradually diminishes the antioxidant systems, causing high levels of oxidative metabolism that affects cell structure, leading to neuronal damage. Accumulating evidence suggests that AD is closely related to a dysfunction of both insulin signaling and glucose metabolism in the brain, leading to an insulin-resistant brain state. Four drugs are currently used for this pathology: Three FDA-approved cholinesterase inhibitors and one NMDA receptor antagonist. However, wide varieties of antioxidants are promissory to delay or prevent the symptoms of AD and may help in treating the disease. Therefore, therapeutic efforts to achieve attenuation of oxidative stress could be beneficial in AD treatment, attenuating Aß-induced neurotoxicity and improve neurological outcomes in AD. The term inflammaging characterizes a widely accepted paradigm that aging is accompanied by a low-grade chronic up-regulation of certain pro-inflammatory responses in the absence of overt infection, and is a highly significant risk factor for both morbidity and mortality in the elderly.

The aminoestrogen prolame increases recognition memory and hippocampal neuronal spine density in aged mice.

The aging brain shows biochemical and morphological changes in the dendrites of pyramidal neurons from the limbic system associated with memory loss. Prolame (N-(3-hydroxy-1,3,5 (10)-estratrien-17ß-yl)-3-hydroxypropylamine) is a non-feminizing aminoestrogen with antithrombotic activity that prevents neuronal deterioration, oxidative stress, and neuroinflammation. Our aim was to evaluate the effect of prolame on motor and cognitive processes, as well as its influence on the dendritic morphology of neurons at the CA1, CA3, and granule cells of the dentate gyrus (DG) regions of hippocampus (HP), and medium spiny neurons of the nucleus accumbens (NAcc) of aged mice. Dendritic morphology was assessed with the Golgi-Cox stain procedure followed by Sholl analysis. Prolame (60 µg/kg) was subcutaneously injected daily for 60 days in 18-month-old mice. Immediately after treatment, locomotor activity in a new environment and recognition memory using the Novel Object Recognition Task (NORT) were evaluated. Prolame-treated mice showed a significant increase in the long-term exploration quotient, but locomotor activity was not modified in comparison to control animals. Prolame-treated mice showed a significant increase in dendritic spines density and dendritic length in neurons of the CA1, CA3, and DG regions of the HP, whereas dendrites of neurons in the NAcc remained unmodified. In conclusion, prolame administration promotes hippocampal plasticity processes but not in the NAcc neurons of aged mice, thus improving long-term recognition memory. Prolame could become a pharmacological alternative to prevent or delay the brain aging process, and thus the emergence of neurodegenerative diseases that affect memory.

Energy Drink Administration in Combination with Alcohol Causes an Inflammatory Response and Oxidative Stress in the Hippocampus and Temporal Cortex of Rats.

Energy drinks (EDs) are often consumed in combination with alcohol because they reduce the depressant effects of alcohol. However, different researches suggest that chronic use of these psychoactive substances in combination with alcohol can trigger an oxidative and inflammatory response. These processes are regulated by both a reactive astrogliosis and an increase of proinflammatory cytokines such as IL-1ß, TNF-α, and iNOS, causing cell death (apoptosis) at the central and peripheral nervous systems. Currently, mechanisms of toxicity caused by mixing alcohol and ED in the brain are not well known. In this study, we evaluated the effect of chronic alcohol consumption in combination with ED on inflammatory response and oxidative stress in the temporal cortex (TCx) and hippocampus (Hp) of adult rats (90 days old). Our results demonstrated that consuming a mixture of alcohol and ED for 60 days induced an increase in reactive gliosis, IL-1ß, TNF-α, iNOS, reactive oxygen species, lipid peroxidation, and nitric oxide, in the TCx and Hp. We also found immunoreactivity to caspase-3 and a decrease of synaptophysin in the same brain regions. The results suggested that chronic consumption of alcohol in combination with ED causes an inflammatory response and oxidative stress, which induced cell death via apoptosis in the TCx and Hp of the adult rats.

Antioxidative stress effect of epicatechin and catechin induced by Aß25-35 in rats and use of the electrostatic potential and the Fukui function as a tool to elucidate specific sites of interaction.

Alzheimer's disease (AD) is a neurodegenerative disorder caused by the aggregation of the amyloid-beta peptide (Aß) in senile plaques and cerebral vasculature. The Aß25-35 fraction has shown the most toxicity; its neurotoxic mechanisms are associated with the generation of oxidative stress and reactive astrogliosis that induce neuronal death and memory impairment. Studies indicate that pharmacological treatment with flavonoids reduces the rate of AD, in particular, it has been shown that antioxidants are compounds that could interact with this peptide due to their antioxidant proprieties. In this study, experimental and computational tools were used to calculate the molecular electrostatic potential and the Fukui function with the Gaussian 09 computational program, to predict the most reactive parts of these molecules and make the complex between Aß25-35 and two flavonoids (catechin and epicatechin) in the absolute gas-phase, where a possible interaction between them was observed. This is important for understanding the Aß25-35-Flavonoid (A-F) interaction as a therapeutic strategy to inhibit the neurotoxic effects that this peptide causes in AD, which currently is still considered an ambiguous process.

Comparación clínica del uso del colgajo de avance coronal e injerto de tejido conectivo subepitelial con o sin proteínas derivadas de la matriz del esmalte para la cobertura de recesiones gingivales. Caso clínico / Clinical comparison of coronary displaced flap and sub-epithelial connective tissue graft with or without enamel matrix protein derivative for gingival recession coverage. Clinical case presentation

Se presenta un caso clínico donde se evaluó si la agregación del derivado de la matriz del esmalte (DME) al procedimiento del colgajo de avance coronal con injerto de tejido conectivo subepitelial (CDC + ITCS) mejoraría la cantidad de cobertura radicular en recesiones gingivales clase I y II de Miller comparados con el mismo procedimiento solo, en un paciente con recesiones gingivales múltiples a seis meses. Se incluyeron 12 recesiones gingivales, seis tratadas con (CAC + ITCSE + DME) y seis con (CAC + ITCSE) en diferentes cuadrantes. Al inicio y a los seis meses se midieron los parámetros clínicos tales como profundidad de la recesión gingival (PR), profundidad al sondeo (PS), nivel de inserción clínica (NIC), y ancho de tejido queratinizado en dirección apico-coronal (TQ). Un valor p < 0.05 se consideró significativo. Los resultados mostraron que a los seis meses ambos procedimientos, CAC + ITCSE + DME y CAC + ITCSE produjeron una significativa cobertura radicular en promedio 2.83 ± 1.16 mm (p = 0.001) y 2.50 ± 0.83 mm (p = .002), respectivamente. Todas las recesiones gingivales tratadas con el DME tuvieron el 100% de cobertura radicular y sólo el 65.3% de cobertura para los sitios tratados con CAC + ITCSE. Al comparar ambos procedimientos a los seis meses, se observaron mejores resultados con CAC + ITCSE + DME en cuanto al nivel de inserción clínica (p = .02) y la cobertura radicular (p = .06); sin embargo, ni la diferencia del nivel de inserción clínico ni la ganancia en la cobertura radicular mostraron ser significativos. Por otro lado, no se observaron diferencias significativas en la PS y TQ. Conclusión: El presente caso clínico no mostró beneficio adicional cuando se agregó el DME al procedimiento de CAC + ITCSE para la cobertura de recesiones gingivales múltiples clase I y II de Miller.

The present article described a clinical case where it was assessed whether aggregation of enamel matrix derivative (EMD) to the procedure of coronary-advanced flap with sub-epithelial connective tissue graft (CAF + SCTG) would improve the amount of root coverage in Miller's class I and II gingival recessions when compared to the same isolated procedure in a patient suffering multiple gingival recessions, in a 6 month time-span. Twelve gingival recessions were included in the study: six treated with (CAF + SCTG + EMD) and six treated with (CAF + SCTG) in different quadrants. At beginning of procedure as well as six months later, the following clinical parameters were measured: gingival recession depth (RD), depth to probing (PD), clinical insertion level (CIL) and width of keratinized tissue (KT) in apex-coronary direction. A p < 0.05 was considered statistically significant. Results established that after a six month procedure CAF + SCTG + EMD and CAF + SCTG produced significant root coverage, respective averages were 2.83 ± 1.16 mm (p = 0.001) and 2.50 ± 0.83 mm (p = .002). All gingival recessions treated with EMD experienced 100% root coverage, sites treated with CAF + SCTG + EMD exhibited coverage of only 65.3%. When comparing results at six months, better results were observed with CAF + SCTG + EMD with respect to clinical insertion level (p = .02) and root coverage (p = .06). Nevertheless, neither the difference of clinical level insertion nor the gain in root coverage resulted significant. Additionally, no significant differences were observed between PD and KT. Conclusion: The present clinical case did not show additional benefits when EMD were aggregated to the CAF + SCTG in the coverage of multiple Miller's class I and class II gingival recessions.

Unilateral injection of Aß25-35 in the hippocampus reduces the number of dendritic spines in hyperglycemic rats.

Alzheimer's disease (AD) is a neurodegenerative process exacerbated by several risk factors including impaired glucose metabolism in the brain that could cause molecular and neurochemical alterations in cognitive regions such as the hippocampus (Hp). Consequently, this process could cause neuronal morphological changes; however, the mechanism remains elusive. We induced chronic hyperglycemia after streptozotocin (STZ) administration. Then, we examined spatial learning and memory using the Morris water maze test and evaluated neuronal morphological changes using the Golgi-Cox stain procedure in hyperglycemic rats that received a Aß25-35 unilateral injection into the Hp. Our results demonstrate that STZ combined with Aß25-35 induced significant deficits in the spatial memory. In addition, we observed a significant reduction in the number of dendritic spines of pyramidal neurons in the dorsal Hp of rats with STZ plus Aß25-35 . In conclusion, the reduced spine density of pyramidal neurons in the CA1 dorsal Hp could produce the spatial memory deficit observed in these animals. These results suggest that hyperglycemia can trigger Aß-induced neurodegeneration and thus the appearance of AD symptoms would be accelerated. Synapse 68:585-594, 2014. © 2014 Wiley Periodicals, Inc.

Aminoguanidine treatment ameliorates inflammatory responses and memory impairment induced by amyloid-beta 25-35 injection in rats.

Alzheimer disease (AD) is a neurodegenerative disorder caused by accumulation of the amyloid-beta peptide (Aß) in neuritic plaques. Its neurotoxic mechanisms are associated with inflammatory responses and nitrosative stress generation that promote expression of inducible nitric oxide synthase (iNOS) and increased nitric oxide causing neuronal death and memory impairment. Studies suggest that treatment with anti-inflammatory and anti-oxidant agents decreases the risk of developing AD. Aminoguanidine (AG) is an iNOS inhibitor with anti-inflammatory and anti-oxidant effects. In this study, we evaluated the effects of systemic administration of AG (100 mg/kg/day for 4 days) on spatial memory and inflammatory responses induced by an injection of Aß(25-35) [100 µM] into the temporal cortex (TCx) of rats. A significant improvement of spatial memory was evident in the Aß(25-35)-treated group at day 30 post-injection subjected to AG treatment; this effect was correlated with decreases in reactive gliosis, IL-1ß, TNF-α, and nitrite levels, as well as a reduction in neurodegeneration in the TCx and hippocampus (Hp). These results suggest that AG treatment inhibited glia activation and cytokine release, which may help to counteract neurodegenerative events induced by the toxicity of Aß.

Amyloid-ß(25-35) induces a permanent phosphorylation of HSF-1, but a transitory and inflammation-independent overexpression of Hsp-70 in C6 astrocytoma cells.

Two hallmarks of Alzheimer diseases are the continuous inflammatory process, and the brain deposit of Amyloid b (Aß), a cytotoxic protein. The intracellular accumulation of Aß(25-35) fractions, in the absence of Heat Shock proteins (Hsps), could be responsible for its cytotoxic activity. As, pro-inflammatory mediators and nitric oxide control the expression of Hsps, our aim was to investigate the effect of Aß(25-35) on the concentration of IL-1ß, TNF-α and nitrite levels, and their relation to pHSF-1, Hsp-60, -70 and -90 expressions, in the rat C6 astrocyte cells. Interleukin-specific ELISA kits, immunohistochemistry with monoclonal anti-Hsp and anti pHSF-1 antibodies, and histochemistry techniques, were used. Our results showed that Aß25-35 treatment of C6 cells increased, significantly and consistently the concentration of IL-1ß, TNF-α and nitrite 3 days after initiating treatment. The immunoreactivity of C6 cells to Hsp-70 reached its peak after 3 days of treatment followed by an abrupt decrease, as opposed to Hsp-60 and -90 expressions that showed an initial and progressive increase after 3 days of Aß(25-35) treatment. pHSF-1 was identified throughout the experimental period. Nevertheless, progressive and sustained cell death was observed during all the treatment times and it was not caspase-3 dependent. Our results suggest that Hsp-70 temporary expression serves as a trigger to inhibit casapase-3 pathway and allow the expression of Hsp-60 and -90 in C6 astrocytoma cells stimulated with Aß(25-35).

Alteration of the sialylation pattern and memory deficits by injection of Aß(25-35) into the hippocampus of rats.

Sialic acid in glycoconjugates participates in important cellular functions associated with normal development, growth, and communication. Therefore we evaluated the sialylation pattern and memory deficits caused by the injection of Aß((25-35)) into the hippocampus (Hp) of rats. The eight-arm maze spatial-learning and memory test indicated that the injection of Aß((25-35)) into subfield CA1 of the Hp impaired both learning and memory. The sialylation pattern was examined using sialic acid-specific lectins. Our results showed that Maackia amurensis agglutinin (MAA, specific for Neu5Acα2,3Gal) showed reactivity in the CA1 and dentate gyrus (DG) subfields of the Hp mainly in the group injected with vehicle, whereas Macrobrachium rosenbergii lectin (MRL, specific for Neu5,9,7Ac) and Sambucus nigra agglutinin (SNA, specific for Neu5Acα2,6Gal-GalNAc) had increased reactivity in the CA1 and DG subfields of the Hp in the Aß((25-35))-injected group. The staining pattern of the antibody specific for polysialic acid (a linear homopolymer of α-2,8-linked sialic acid) increased in the CA1 and DG subfields of the Hp of the Aß((25-35)) group compared to the control group. Our results suggest that injection of Aß((25-35)) causes impairment in spatial memory and alters the sialylation pattern in response to compensatory reorganization and-or sprouting of dendrites and axons of the surviving neurons.

Sialylated and O-glycosidically linked glycans in prion protein deposits in a case of Gerstmann-Sträussler-Scheinker disease.

Prion diseases are caused by an abnormal form of the prion protein (PrP(Sc)). We identified, with lectins, post-translational modifications of brain proteins due to glycosylation in a Gerstmann-Sträussler-Scheinker (GSS) patient. The lectin Amaranthus leucocarpus (ALL), specific for mucin type O-glycosylated structures (Galß1,3 GalNAcα1,0 Ser/Thr or GalNAcα1,0 Ser/Thr), and Sambucus nigra agglutinin (SNA), specific for Neu5Acα2,6 Gal/GalNAc, showed positive labeling in all the prion deposits and in the core of the PrP(Sc) deposits, respectively, indicating specific distribution of O-glycosylated and sialylated structures. Lectins from Maackia amurensis (MAA, Neu5Acα2,3), Macrobrachium rosenbergii (MrL, Neu5,9Ac2-specific) and Arachis hypogaea (PNA, Gal-specific) showed low staining of prion deposits. Immunohistochemistry colocalization with prion antibody indicated that all lectins stained prion protein deposits. These results show that specific modifications in the glycosylation pattern are closely related to the hallmark lesions and might be an early event in neuronal degeneration in GSS disease.

The amyloid-beta25-35 injection into the CA1 region of the neonatal rat hippocampus impairs the long-term memory because of an increase of nitric oxide.

Alzheimer's disease (AD) is characterized by the amyloid-beta (Abeta) aggregation but it is unclear when this process begins. Previously, we showed that amyloid-beta(25-35) (Abeta(25-35)) increases the nitric oxide (NO) pathways and causes neurodegenerative effects in rats. The excessive increase of NO during brain development can promote a persistent oxidative stress, but the role of the Abeta(25-35) in the neonatal age and its effects over the long term is unclear. Our aim was to evaluate if the Abeta(25-35) injection on postnatal day 7 causes loss in spatial memory by NO pathways in adult rats. Our results showed that neonatal-Abeta(25-35) injection into the hippocampus (Hp) causes significant impairments in the spatial memory after 90 days. The NO levels were found increased and argynophilic in the Hp. Other evidence of neuronal damage was an increase of the immunoreactivity for 3-nitrotyrosine (3-NT) and the glial-fibrilar acid protein (GFAP) in the Hp of the Abeta(25-35) group. In contrast, these effects were blocked by the administration of L-NAME (inhibitor of nitric oxide synthase) before the injection of Abeta(25-35). The L-NAME plus Abeta(25-35) group showed a better performance in the spatial memory compared to the Abeta(25-35) group. In addition in this group we found a decrease of NO, 3-NT and neurodegeneration in the Hp compared to the Abeta(25-35) group. This finding is a novel result about the role of Abeta(25-35) during the neonatal stage that enhances the NO production, which appears to impair the spatial memory in adult rats.

Neuroprotective effect of alpha-asarone on spatial memory and nitric oxide levels in rats injected with amyloid-beta((25-35)).

The chemical alpha-asarone is an important active substance of the Acori graminei rhizome (AGR). It has pharmacological effects that include antihyperlipidemic, antiinflammatory, and antioxidant activity. Our aim was to study the effects alpha-asarone on nitric oxide (NO) levels in the hippocampus and temporal cortex of the rat after injection of the fraction 25-35 from amyloid-beta (Abeta((25-35))). In addition we examined the working spatial memory in an eight-arm radial maze. Our results showed a significant increase of nitrites in the hippocampus and temporal cortex of Abeta((25-35))-treated rats. Other evidence of neuronal damage was the expression of a glial-fibrillar-acid protein and a silver staining. There were impairments in the spatial memory evaluated in the eight-arm radial maze. We wanted to determine whether alpha-asarone improves the memory correlated with NO overproduction and neuronal damage caused by the injection of Abeta((25-35)) into rats. Then animals received a 16-day treatment of alpha-asarone before the Abeta((25-35)) injection. Our results show a significant decrease of nitrite levels in the hippocampus and temporal cortex, without astrocytosis and silver-staining cells, which correlates with memory improvement in the alpha-asarone-treated group. Our results suggest that alpha-asarone may protect neurons against Abeta((25-35))-caused neurotoxicity by inhibiting the effects of NO overproduction in the hippocampus and temporal cortex.

Amyloid-beta(25-35) impairs memory and increases NO in the temporal cortex of rats.

beta-Amyloid plays an important role in the neurodegeneration process of Alzheimer's disease (AD), but its neurotoxic mechanisms are not clear. It has been associated with the increase of oxidative stress and cognitive impairment because the beta-amyloid peptide 25-35 (Abeta((25-35))) has the critical neurotoxic properties of the full-length Abeta(1-42). Our present study shows the role of Abeta((25-35)) when injected into the temporal cortex on the nitric oxide pathways, 3-nitrotyrosine, neuronal death, and the spatial memory of rats 1 month after the injection. Our data showed that Abeta((25-35)) increases oxidative stress, causes neuronal damage, and decreases spatial memory in rats. Notably, the injection of the fraction Abeta((25-35)) caused an increase of nNOS and iNOS immunoreactivity in the temporal cortex and hippocampus. We demonstrated a significant increase of reactive astrocytosis, which was accompanied by neuronal damage in the temporal cortex and hippocampus of rats injected with Abeta((25-35)). These data suggest that the fraction Abeta((25-35)) injected into the temporal cortex might contribute to understanding the role of nitric oxide on the biological changes related to the neuropathological progression and the memory impairment in AD.