CENTRAL AND PERIPHERAL EFFECT OF MPTP VIA DOSE-DEPENDENT MAGNESIUM MODULATION.

Background: Recent studies suggested that MPTP could cause gastrointestinal motility deficits additionally to its nonconclusive and controverted effects on the CNS (behavior and brain oxidative stress) in rats. A possible interaction between MPTP typical impairments and magnesium modulatory potential was previously suggested, as magnesium role was described in neuroprotection, gastrointestinal function, and oxidative stress. Aim: To investigate the possible modulatory effect of several magnesium intake formulations (via drinking water) in MPTP neurotoxicity and functional gastrointestinal impairment induction. Materials and Methods: Adult male Wistar rats were subjected to 3-week magnesium intake-controlled diets (magnesium depleted food and magnesium enriched drinking water) previously to acute subcutaneous MPTP treatment (30 mg/ kg body weight). Gastrointestinal motility (one hour stool collection test), and behavioral patterns (Y maze task, elevated plus maze test, open field test, forced swim test) were evaluated. Followingly, brain and bowel samples were collected, and oxidative stress was evaluated (glutathione peroxidase activity, malondial-dehyde concentrations). Results: MPTP could lead to magnesium intake-dependent constipation-like gastrointestinal motility impairments, anxiety- and depressive-like affective behavior changes, and mild pain tolerance defects. Also, we found similar brain and intestinal patterns in magnesium-dependent oxidative stress. Conclusion: While the MPTP effects in normal magnesium intake could be regarded as not fully relevant in rat models and limited to the current experimental conditions, the abnormalities observed in the affective behavior, gastrointestinal status, pain tolerance, peripheric and central oxidative status could be indicative of the extent of the systemic effects of MPTP that are not restricted to the CNS level, but also to gastro-intestinal system.

Serum anti-GM2 and anti-GalNAc-GD1a IgG antibodies are biomarkers for acute canine polyradiculoneuritis.

OBJECTIVES: A previous single-country pilot study indicated serum anti-GM2 and anti-GA1 anti-glycolipid antibodies as potential biomarkers for acute canine polyradiculoneuritis. This study aims to validate these findings in a large geographically heterogenous cohort. MATERIALS AND METHODS: Sera from 175 dogs clinically diagnosed with acute canine polyradiculoneuritis, 112 dogs with other peripheral nerve, cranial nerve or neuromuscular disorders and 226 neurologically normal dogs were screened for anti-glycolipid antibodies against 11 common glycolipid targets to determine the immunoglobulin G anti-glycolipid antibodies with the highest combined sensitivity and specificity for acute canine polyradiculoneuritis. RESULTS: Anti-GM2 anti-glycolipid antibodies reached the highest combined sensitivity and specificity (sensitivity: 65.1%, 95% confidence interval 57.6 to 72.2%; specificity: 90.2%, 95% confidence interval 83.1 to 95.0%), followed by anti-GalNAc-GD1a anti-glycolipid antibodies (sensitivity: 61.7%, 95% confidence interval 54.1 to 68.9%; specificity: 89.3%, 95% confidence interval 82.0 to 94.3%) and these anti-glycolipid antibodies were frequently present concomitantly. Anti-GA1 anti-glycolipid antibodies were detected in both acute canine polyradiculoneuritis and control animals. Both for anti-GM2 and anti-GalNAc-GD1a anti-glycolipid antibodies, sex was found a significantly associated factor with a female to male odds ratio of 2.55 (1.27 to 5.31) and 3.00 (1.22 to 7.89), respectively. Anti-GalNAc-GD1a anti-glycolipid antibodies were more commonly observed in dogs unable to walk (OR 4.56, 1.56 to 14.87). CLINICAL SIGNIFICANCE: Anti-GM2 and anti-GalNAc-GD1a immunoglobulin G anti-glycolipid antibodies represent serum biomarkers for acute canine polyradiculoneuritis.

Interictal cardiac autonomic nervous system disturbances in dogs with idiopathic epilepsy.

Autonomic nervous system (ANS) activity in the interictal period (InIp) in dogs with presumed idiopathic epilepsy (pIE) was assessed using heart rate variability (HRV) analysis. The HRVs obtained from 28 pIE dogs with interictal epileptic discharges (InIEd; 11 with treatment and 17 without treatment) detected on electroencephalography (EEG) were compared with those obtained from 13 healthy dogs. On electrocardiographic (ECG) study, the P wave dispersion (PWD; P<0.001), P max (P=0.004) and corrected QT interval (QTc; P=0.025) were significantly increased in the pIE group. On the basis of HRV analysis, the pIE dogs had an increased activity of the parasympathetic component of the ANS, including the percentage of R-R interval (pNN50%) that differs more than 50ms (P=0.011) and high frequency band (HF; P=0.041). Administration of phenobarbitone had no influence on the ANS pattern when pIE subgroups were compared (P>0.05). In InIp, dogs elicited specific conductibility delays of the electrical impulses (increased PWD and QTc interval); these delays are considered to be risk factors for developing severe arrhythmias, such as atrial fibrillation and ventricular tachycardia. When compared with human beings, a different ANS pattern characterised by increased parasympathetic activity was observed, which may influence the therapeutic approach of IE in dogs.

Intranasal Midazolam versus Rectal Diazepam for the Management of Canine Status Epilepticus: A Multicenter Randomized Parallel-Group Clinical Trial.

BACKGROUND: Intranasal administration of benzodiazepines has shown superiority over rectal administration for terminating emergency epileptic seizures in human trials. No such clinical trials have been performed in dogs. OBJECTIVE: To evaluate the clinical efficacy of intranasal midazolam (IN-MDZ), via a mucosal atomization device, as a first-line management option for canine status epilepticus and compare it to rectal administration of diazepam (R-DZP) for controlling status epilepticus before intravenous access is available. ANIMALS: Client-owned dogs with idiopathic or structural epilepsy manifesting status epilepticus within a hospital environment were used. Dogs were randomly allocated to treatment with IN-MDZ (n = 20) or R-DZP (n = 15). METHODS: Randomized parallel-group clinical trial. Seizure cessation time and adverse effects were recorded. For each dog, treatment was considered successful if the seizure ceased within 5 minutes and did not recur within 10 minutes after administration. The 95% confidence interval was used to detect the true population of dogs that were successfully treated. The Fisher's 2-tailed exact test was used to compare the 2 groups, and the results were considered statistically significant if P < .05. RESULTS: IN-MDZ and R-DZP terminated status epilepticus in 70% (14/20) and 20% (3/15) of cases, respectively (P = .0059). All dogs showed sedation and ataxia. CONCLUSIONS AND CLINICAL IMPORTANCE: IN-MDZ is a quick, safe and effective first-line medication for controlling status epilepticus in dogs and appears superior to R-DZP. IN-MDZ might be a valuable treatment option when intravenous access is not available and for treatment of status epilepticus in dogs at home.

Evaluation of central vestibular syndrome in dogs using brainstem auditory evoked responses recorded with surface electrodes / Avaliação da síndrome vestibular central em cães usando respostas evocadas auditivas do tronco cerebral gravadas com eletrodos de superfície

The present study aimed to analyse the wave morphology, amplitude, latency, and intervals of the brainstem auditory evoked responses (BAERs) in dogs with central vestibular syndrome (CVS) recorded with surface electrodes. Ten dogs with CVS were examined by mono- and binaural stimulation, using the Neuropack electrodiagnostic system, with stimulus intensities of 90 dBSPL. BAERs examinations revealed morphological changes of waves I, II, III, and V and decreased amplitudes of all waves in 7/10 dogs. P values obtained were = 0.014 for wave I amplitude, 0.031 for II, and III and 0.032 for V. Comparing the latencies of waves I, II, III, and V generated by right and left monoaural stimulation in dogs with CVS, we did not observe significant differences (P > 0.05). No statistical differences were observed for BAERs latencies of the waves recorded after binaural and monaural stimulation (left or right). As far as we know, this is the first study of BAERs using surface electrodes, obtained from dogs with CVS.(AU)

Este estudo destina-se à análise da morfologia, da amplitude, da latência e do intervalo das ondas das respostas evocadas auditivas no tronco cerebral (BAERs) em cães com síndrome vestibular central (CVS) registrados com eletrodos de superfície. Dez cães com CVS foram examinados por estimulação mono e binaural usando um sistema de eletrodiagnóstico Neuropack, com intensidade do estímulo de 90 dBSPL. Os exames BAERs relevaram alterações morfológicas das ondas I, II, III e V, bem como baixas amplitudes para todas as ondas no caso dos 7/10 cães. Os valores de P obtidos foram = 0.014 para ampitude da onda I, 0.031 para a II e 0.032 para a V. Compararam-se as latências das ondas I, II, III e V geradas pelo estímulo monoaural direito e esquerdo em cães com CVS e não foram constatadas diferenças significativas (P > 0.05). Igualmente não foram observadas diferenças estatísticas no caso das latências BAERs no que diz respeito às ondas gravadas depois de estímulos binaural e monoaural (esquerdo ou direito). Pelo que é de conhecimento dos autores da presente pesquisa, este é o primeiro estudo sobre BAERs usando eletrodos de superfície obtidos em cães com CVS.(AU)