Amanda Oliveira de Andrades

Neuroprotective role of quercetin in locomotor activities and cholinergic neurotransmission in rats experimentally demyelinated with ethidium bromide

AIM The purpose of this study was to investigate whether the flavonoid quercetin can prevent alterations in the behavioral tests and of cholinergic neurotransmission in rats submitted to the ethidium bromide (EB) experimental demyelination model during events of demyelination and remyelination. MAIN METHODS Wistar rats were randomly distributed into four groups (20 animals per group): Control (pontine saline injection and treatment with ethanol), Querc (pontine saline injection and treatment with quercetin), EB (pontine 0.1% EB injection and treatment with ethanol), and EB+Querc (pontine 0.1% EB injection and treatment with quercetin). The groups Querc and Querc+EB were treated once daily with quercetin (50mg/kg) diluted in 25% ethanol solution (1ml/kg) and the animals of the control and EB groups were treated once daily with 25% ethanol solution (1ml/kg). Two stages were observed: phase of demyelination (peak on day 7) and phase of remyelination (peak on day 21 post-injection). Behavioral tests (beam walking, foot fault and inclined plane test), acetylcholinesterase (AChE) activity and lipid peroxidation in pons, cerebellum, hippocampus, hypothalamus, striatum and cerebral cortex were measured. KEY FINDINGS The quercetin promoted earlier locomotor recovery, suggesting that there was demyelination prevention or further remyelination velocity as well as it was able to prevent the inhibition of AChE activity and the increase of lipidic peroxidation, suggesting that this compound can protect cholinergic neurotransmission. SIGNIFICANCE These results may contribute to a better understanding of the neuroprotective role of quercetin and the importance of an antioxidant diet in humans to provide benefits in neurodegenerative diseases such as MS.

Doenças neurológicas em cães atendidos no Hospital Veterinário da Universidade Federal de Santa Maria, RS: 1.184 casos (2006-2013)

A retrospective study including dogs with neurological disease was conducted at the Service of Neurology (SN) of the Veterinary Teaching Hospital, Universidade Federal de Santa Maria (UFSM) from 2006 to 2013, with the objective to identify and characterize age, breed, sex and to neurological diseases, and classify them accordingly to the anatomical region and DINAMIT-V acronym. There were evaluated 1,277 neurological records of dogs and obtained the information for inclusion in the study in 1,184 of them being the diagnosis confirmed in 525 (44.4%) and presumptive in 659 dogs (55.6%). The most common breed was Dachshund (28.7%), followed by mixed breed. The most affected sites were the spinal cord between T3-L3 (40.9%) and thalamus-cortex (17.5%). Most dogs were diagnosed with degenerative disorders (49%), being intervertebral disk disease the most observed, followed by inflammatory/infectious diseases (16.6%). It can be concluded that the higher prevalence of neurological disorders in dogs involve the spinal cord and thalamus-cortex, with the most frequent being degenerative and the data obtained may assist future studies associated with frequency and distribution of the main neurological diseases in dogs.

Epilepsia em cães: 66 casos (2005-2010)

The objective of this study was to identify dogs with epilepsy and to obtain information about breed, sex, age, classification of the epilepsy and the seizures, as well as the stage and time of occurrence of the seizures. Epilepsy was primary in 66.7% (44/66) of dogs, symptomatic in 21.2% (14/66), and probably symptomatic in 12.1% (8/66). Crossbred dogs (27%) were the most affected and the predominant age group ranged from one to five years; the generalized tonic-clonic seizures (66.7%) was the most frequent presentation. The search for the owner (72.7%) during the preictal period and the compulsive walking (60.5%) in post-ictal period were the more frequent signs observed in the affected dogs, and the occurrence of seizures was higher at night (79.2%).

Quercetin treatment regulates the Na+,K+-ATPase activity, peripheral cholinergic enzymes, and oxidative stress in a rat model of demyelination

Quercetin is reported to exert a plethora of health benefits through many different mechanisms of action. This versatility and presence in the human diet has attracted the attention of the scientific community, resulting in a huge output of in vitro and in vivo (preclinical) studies. Therefore, we hypothesized that quercetin can protect Na+,K+-ATPase activity in the central nervous system, reestablish the peripheral cholinesterases activities, and reduce oxidative stress during demyelination events in rats. In line with this expectation, our study aims to find out how quercetin acts on the Na+,K+-ATPase activity in the central nervous system, peripheral cholinesterases, and stress oxidative markers in an experimental model of demyelinating disease. Wistar rats were divided into 4 groups: vehicle, quercetin, ethidium bromide (EB), and EB plus quercetin groups. The animals were treated once a day with vehicle (ethanol 20%) or quercetin 50 mg/kg for 7 (demyelination phase, by gavage) or 21 days (remyelination phase) after EB (0.1%, 10 μL) injection (intrapontine).The encephalon was removed, and the pons, hypothalamus, cerebral cortex, hippocampus, striatum, and cerebellum were dissected to verify the Na+,K+-ATPase activity. Our results showed that quercetin protected against reduction in Na+,K+-ATPase in the pons and cerebellum in the demyelination phase, and it increased the activity of this enzyme in the remyelination phase. During the demyelination, quercetin promoted the increase in acetylcholinesterase activity in whole blood and lymphocytes induced by EB, and it reduced the increase in acetylcholinesterase activity in lymphocytes in the remyelination phase. On day 7, EB increased the superoxide dismutase and decreased catalase activities, as well as increased the thiobarbituric acid-reactive substance levels. Taken together, these results indicated that quercetin regulates the Na+,K+-ATPase activity, affects the alterations of redox state, and participates in the reestablishment of peripheral cholinergic activity during demyelinating and remyelination events.

Sonda uretral flexível como método alternativo para aferição invasiva da pressão intracraniana em trauma cranioencefálico induzido em coelhos

The aim of this study was to evaluate the use of flexible urethral catheter as an alternative method for measuring intracranial pressure in rabbits with head trauma induced by 4 F Fogarty catheter (epidural balloon) and compare the data obtained with the conventional method of ventriculostomy catheter. In this study, New Zealand rabbits were randomly distributed into two groups, G1: measuring the ICP with ventriculostomy catheter (n=6) and G2: measuring the ICP with urethral catheter (n=6). Two craniotomies were performed in the right and left parietal region for the implantation of a ventriculostomy catheter and/or flexible urethral catheter and epidural 4 Fr Fogarty arterial embolectomy catheter, respectively. MAP, CPP, HR, RF and RT values were measured before and after of the craniotomy. The ICP value was measured after craniotomy, every five minutes during 40 minutes after the balloon was inflated with 0.3 ml with NaCl and further 40 minutes after the balloon was inflated with 0.6 ml. The ICP value increased in both groups; however, the ICP values were lower in the flexible urethral catheter. The flexible urethral catheter can be used as an alternative method to measure ICP values in rabbits with head injury.

Therapeutic Aspects of Dogs with Presumptive Diagnosis of Idiopathic Epilepsy

Background: Epilepsy is a chronic neurological condition characterised by recurrent epileptic seizures. Various antiepileptic drugs are used for the management of canine idiopathic epilepsy. Phenobarbital is the drug of choice for long-term treatment in dogs. Although it is well tolerated, phenobarbital can cause liver injury if administered alone or in combination with other drugs. Therefore, the main of this study was to identify dogs with presumptive diagnosis of idiopathic epilepsy and information about the antiepileptic drugs, the dose and frequency of administration, period of treatment, frequency of the seizure before and after start the treatment, complementary exams and adverse effects. Materials, Methods & Results: In this study were included 21 dogs with idiopathic epilepsy. All dogs were examined and having blood taken for blood count, biochemical tests (ALT, AST, AP, total protein, albumin, creatinine, urea, amylase, lipase, cholesterol and triglycerides), measurement of serum phenobarbital and/or potassium bromide and, some dogs, free T4 by dialysis and canine TSH. In this study, it was observed monotherapy (phenobarbital) in 76.19% (16/21), double therapy (phenobarbital and potassium bromide) in 19.05% (4/21) and triple therapy (phenobarbital, potassium bromide and gabapentin) in 4.76% (1/21) of dogs. The phenobarbital was used as monotherapy with dose between 1.4 and 12 mg kg-1 and the median of serum concentration was 26.41 μg kg-1. There was significant reduction in the frequency of the seizure after start the treatment. There was refractory to antiepileptic drugs in two dogs (9.5%). In blood analysis, there was increase serum activities of AP (23.81%) and ALT (14.20%), decrease total protein (42.29%), hypoalbuminemia (9.5%) and it was not increased AST activities. The main adverse effects were nodularliver damage and hypothyroidism. Discussion: In most cases of dogs with idiopathic epilepsy, monotherapy is preferred, because it tends to avoid complications that may arise from drug interactions and may also improve compliance by providing a simple treatment regimen. In this study, the phenobarbital controlled the seizures when used as monotherapy. It is considered success of an antiseizure drug when there is a reduction of seizure frequency by at least 50%, with minimal drug side effects. Approximately 20-30% of dogs with epilepsy do not have satisfactory seizure control or experience intolerable adverse effects with appropriate conventional medical treatment. In this study, there was refractory to antiepileptic drugs in 9.5%, one dog treated with phenobarbital and other with phenobarbital and potassium bromide. The long-term use of phenobarbital causes increase in liver enzymes, ALT and, mainly, ALP, these are attributed to enzymatic induction and to low degree of liver damage. ALT and AP increased the values and this does not necessarily indicate clinically significant liver damage or the need to stop therapy. The risk of liver toxicity appears to be greater with concentrations higher than 35 μg mL-1 or when multiple potentially hepatotoxic drugs are used. Other factors associated to the long-term use of anticonvulsant, such phenobarbital, potassium bromide or both, for the treatment of idiopathic epilepsy in dogs is acute pancreatitis and hypothyroidism. In this study, it was not observed acute pancreatitis, but there were two dogs with hypothyroidism. The long-term use of phenobarbital did not cause significant side effects, even with changes in the biochemical tests.

Heating produced by therapeutic ultrasound in the presence of a metal plate in the femur of canine cadavers.

O objetivo deste estudo foi avaliar o aquecimento gerado pelo ultrassom terapeutico (UST) na placa ossea metalica e estruturas adjacentes apos a fixacao no femur de cadaveres caninos. Foram utilizados dez pares de membros pelvicos, distribuidos igualmente entre os grupos que utilizaram as frequencias de 1 e 3 MHz. Cada frequencia testou as intensidades de 1 e 2 W/cm², sendo que o membro pelvico direito foi definido grupo controle (ausencia da placa ossea metalica) e o membro pelvico esquerdo o grupo teste (presenca da placa ossea metalica). Portanto, os grupos controles foram denominados GCI, com UST na frequencia de 1 MHz e intensidade de 1 W/cm²; GCII, com 1 MHz e 2 W/cm²; GCIII, com frequencia de 3 MHz e intensidade de 1 W/cm²; e GCIV, com 3 MHz e 2 W/cm². Para cada grupo controle, seu respectivo grupo teste foi denominado GTI, GTII, GTIII e GTIV. O UST foi aplicado na face lateral da coxa, utilizando o modo continuo, transdutor de 3,5cm², em uma area de 6,25cm², durante dois minutos. Foram utilizados sensores acoplados a termometros digitais que mediram a temperatura em diferentes locais antes (t0) e apos (t1) a aplicacao do UST. Pode-se verificar que as temperaturas em t1 foram maiores em todos os grupos testados. Os grupos que testaram a frequencia de 3 MHz demonstraram que a temperatura intramuscular foi significativamente maior (P<0,05) na presenca da placa ossea metalica. O ultrassom terapeutico no modo continuo de 1 e 3 MHz e intensidades de 1 e 2 W/cm2durante dois minutos promove o aquecimento da placa ossea metalica e estruturas adjacentes apos a fixacao no femur de cadaveres caninos.