Anticonvulsant Effectiveness and Neurotoxicity Profile of 4-butyl-5-[(4-chloro-2-methylphenoxy)methyl]-2,4-dihydro-3H-1,2,4-triazole-3-thione (TPL-16) in Mice.

Protective (antiseizure) effects of 4-butyl-5-[(4-chloro-2-methylphenoxy)-methyl]-2,4-dihydro-3H-1,2,4-triazole-3-thione (TPL-16) and acute neurotoxic effects were determined in the tonic-clonic seizure model and rotarod test in mice. The interaction profile of four classic antiepileptic drugs (carbamazepine, phenobarbital, phenytoin and valproate) with TPL-16 was also determined in the tonic-clonic seizure model in mice. The protective effects of TPL-16 from tonic-clonic seizures (as ED50 values) and acute neurotoxic effects of TPL-16 (as TD50 values) were determined in 4 pretreatment times (15, 30, 60 and 120 min after its i.p. administration), in adult male albino Swiss mice. The interaction profile of TPL-16 with carbamazepine, phenobarbital, phenytoin and valproate in the tonic-clonic seizure model was determined with isobolographic analysis. Total concentrations of carbamazepine, phenobarbital, phenytoin and valproate were measured in the mouse brain homogenates. The candidate for novel antiepileptic drug (TPL-16) administered separately 15 min before experiments, has a beneficial profile with protective index (as ratio of TD50 and ED50 values) amounting to 5.58. The combination of TPL-16 with valproate produced synergistic interaction in the tonic-clonic seizure model in mice. The combinations of TPL-16 with carbamazepine, phenobarbital and phenytoin produced additive interaction in terms of protection from tonic-clonic seizures in mice. None of the total brain concentrations of classic AEDs were changed significantly after TPL-16 administration in mice. Synergistic interaction for TPL-16 with valproate and the additive interaction for TPL-16 with carbamazepine, phenobarbital and phenytoin in the tonic-clonic seizures in mice allows for recommending TPL-16 as the promising drug for further experimental and clinical testing.

Anticonvulsant and neurotoxic effects of a novel 1,2,4-triazole-3-thione derivative (TPF-34) and its isobolographic interaction profile with classical antiepileptic drugs in mice.

BACKGROUND: Anticonvulsant and acute toxic effects of 5-[(3-fluorophenyl)ethyl]-4-(n-hexyl)-2,4-dihydro-3H-1,2,4-triazole-3-thione (TPF-34)-a candidate for novel antiepileptic drug-were examined in the maximal electroshock-induced seizure (MES) model and rotarod test in mice. The interaction profile of TPF-34 with four classical antiepileptic drugs (carbamazepine, phenobarbital, phenytoin and valproate) was also studied in the mouse MES model. METHODS: Both ED50 and TD50 values for TPF-34 were determined at four treatment times (15, 30, 60 and 120 min after i.p. administration) in the MES model and rotarod test in adult male albino Swiss mice, respectively. The influence of TPF-34 on the protective anticonvulsant action of carbamazepine, phenobarbital, phenytoin and valproate in the mouse MES model was assessed with isobolographic analysis of interaction. Total brain antiepileptic drug concentrations were measured with fluorescence polarization immunoassay. RESULTS: TPF-34, when administered alone at four pretreatment times (15, 30, 60 and 120 min before experiments), possessed a favorable preclinical profile with the protective index (a ratio of TD50 and ED50 values) ranging from 2.89 to 3.53. Moreover, TPF-34, when combined with carbamazepine, phenobarbital, phenytoin and valproate, exerted an additive interaction in the MES model in mice. TPF-34 had no impact on total brain antiepileptic drug concentrations in mice. CONCLUSIONS: A protective index value higher than 3 allows recommending TPF-34 as a promising antiepileptic drug candidate for further preclinical testing using other experimental seizure models. The additive interaction of TPF-34 with carbamazepine, phenobarbital, phenytoin and valproate in the mouse MES model is worthy of recommendation to further clinical studies.

Synthesis and Pharmacological Evaluation of 3-[(4-Oxo-4H-pyrido[3,2-e][1,3]thiazin-2-yl)(phenyl)amino]propanenitrile Derivatives as Orally Active AMPA Receptor Antagonists.

In our search for novel orally active α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor antagonists, we found that conversion of an allyl group in the lead compound 2-[allyl(4-methylphenyl)amino]-4H-pyrido[3,2-e][1,3]thiazin-4-one (4) to a 2-cyanoethyl group significantly increased inhibitory activity against AMPA receptor-mediated kainate-induced toxicity in rat hippocampal cultures. Here, we synthesized 10 analogs bearing a 2-cyanoethyl group and administered them to mice to evaluate their anticonvulsant activity in maximal electroshock (MES)- and pentylenetetrazol (PTZ)-induced seizure tests, and their effects on motor coordination in a rotarod test. 3-{(4-Oxo-4H-pyrido[3,2-e][1,3]thiazin-2-yl)[4-(trifluoromethoxy)phenyl]amino}propanenitrile (25) and 3-[(2,2-difluoro-2H-1,3-benzodioxol-5-yl)(4-oxo-4H-pyrido[3,2-e][1,3]thiazin-2-yl)amino]propanenitrile (27) exhibited potent anticonvulsant activity in both seizure tests and induced minor motor disturbances as indicated in the rotarod test. The protective index values of 25 and 27 for MES-induced seizures (10.7 and 12.0, respectively) and PTZ-induced seizures (6.0 and 5.6, respectively) were considerably higher compared with those of YM928 (5) and talampanel (1).

Pre-contact lens and pre-corneal tear film kinetics.

PURPOSE: Contact lenses (CL) insulate the corneal surface from the environment. It is possible that they influence the corneal sensory mechanism that contribute to spontaneous blinking. The study objective was to quantify the pre-CL and pre-corneal tear film kinetics (TFK) over blink period. METHODS: The study population was 202 soft CL wearers, 133 non-lens wearers. TFK were quantified via post-hoc masked analysis of HD Tearscope videos. The parameters were: Non-Invasive Break Up Time (NIBUT), Exposed Area % at initial break (EA 1st Break) and at blink (EA Blink), Interblink period (IB), Protective Index (PI) and exposure speed of surface dehydration (ES mm2/s). The TFK of CL wearers were compared to non-lens wearers. The hypothesis was that pre-CL TFK was inferior to pre-corneal, specifically greater tear film anomalies presence at blink. RESULTS: The pre-corneal NIBUT was longer than pre-CL NIBUT (9.1 vs. 5.1s, p < 0.001). The EA 1st Break was smaller for pre-corneal than pre-CL (0.003 vs. 0.43%, p < 0.001). The mean IB time was similar for pre-CL and pre-corneal (9.4 vs. 9.8s, p = 0.213). The EA Blink % was smaller for pre-corneal than pre-CL (0.03 vs. 6.66%, p < 0.001). The ES was faster for pre-CL than pre-corneal (0.339 vs. 0.004, p < 0.001). The PI was greater for pre-corneal than pre-CL (99.9 vs. 97.1%, p < 0.001). CONCLUSIONS: Pre-CL TFK were significantly inferior than pre-corneal, confirmed the hypothesis. The NIBUT was shorter. Once the initial break occurred, ES was faster, and EA was much greater for pre-CL than pre-corneal. The differences identified may be an aetiological component of CL discomfort and the relationship between TFK and discomfort in contact lens wearers should be investigated.

Protective role of Brucella abortus specific murine antibodies in inhibiting systemic proliferation of virulent strain 544 in mice and guinea pig.

AIM: The major objective of the investigation was to evaluate the hitherto uncharacterized potential of Brucella-specific antibodies to win the battle against virulent Brucellaabortus infection. MATERIALS AND METHODS: Brucella-specific immune serum was raised in mice. The antibody titer of serum was determined by standard tube agglutination test and indirect enzyme-linked immunosorbent assays (iELISA). Groups of mice and guinea pigs were passively immunized with serum containing specific agglutinin titers. 24 h after immunization, all animals along with unimmunized controls were challenged with B. abortus S544. Total B. abortus S544 counts in the spleen of each animal collected on the 7th day of challenge was determined to evaluate the protective index (PI) of anti-Brucella serum by statistical analysis. RESULT: A dose-dependent protective response to immune mice serum was observed in both experimental models though the values of PI of mice were higher than those obtained for guinea pigs. The PI values in mice passively immunized with 50 IU or 25 IU antibodies were 1.38 and 0.69, respectively. In guinea pigs, however, animals passively immunized with 50 IU or 25 IU antibodies showed PI values equivalent to 0.79 and 0.41, respectively. CONCLUSION: The observations support our hypothesis that the presence of antibodies inhibits the initial multiplication and eventual colonization of systemic organs by B. abortus. Therefore, a predominant antibody-mediated response induced by a vaccine is expected to protect the animal against the most severe clinical outcome of infection.

Risk Factors and Risk-Based Protective Factors for Violent Offending: A Study of Young Victorians.

PURPOSE: The present study aims to examine risk factors and risk-based and interactive protective factors for violent offending in a group of 437 young Australians. METHODS: Participants were recruited into the study when they were in Grade 5 (10-11 years) and followed up almost annually until young adulthood (18-19 years). Measures of violent offending, risk and protective factors, and demographics were obtained through a modification of the Communities That Care youth survey. The data collected enabled identification of groups of students at-risk of violent offending according to drug use, low family socioeconomic status, and antisocial behavior. RESULTS: Results showed that there were very few associations between the risk factors and risk-based protective factors measured in this study (e.g., belief in the moral order, religiosity, peer recognition for prosocial involvement, attachment to parents, low commitment to school, and poor academic performance) and later self-reported violent offending. There were no statistically significant interactive protective factors. CONCLUSIONS: Further longitudinal analyses with large sample sizes are needed to examine risk factors and risk-based protective factors and interactive protective factors in at-risk groups. The findings support the need for multi-faceted prevention and early intervention approaches that target multiple aspects of youth's lives.

Towards cheminformatics-based estimation of drug therapeutic index: Predicting the protective index of anticonvulsants using a new quantitative structure-index relationship approach.

The overall efficacy and safety profile of a new drug is partially evaluated by the therapeutic index in clinical studies and by the protective index (PI) in preclinical studies. In-silico predictive methods may facilitate the assessment of these indicators. Although QSAR and QSTR models can be used for predicting PI, their predictive capability has not been evaluated. To test this capability, we developed QSAR and QSTR models for predicting the activity and toxicity of anticonvulsants at accuracy levels above the literature-reported threshold (LT) of good QSAR models as tested by both the internal 5-fold cross validation and external validation method. These models showed significantly compromised PI predictive capability due to the cumulative errors of the QSAR and QSTR models. Therefore, in this investigation a new quantitative structure-index relationship (QSIR) model was devised and it showed improved PI predictive capability that superseded the LT of good QSAR models. The QSAR, QSTR and QSIR models were developed using support vector regression (SVR) method with the parameters optimized by using the greedy search method. The molecular descriptors relevant to the prediction of anticonvulsant activities, toxicities and PIs were analyzed by a recursive feature elimination method. The selected molecular descriptors are primarily associated with the drug-like, pharmacological and toxicological features and those used in the published anticonvulsant QSAR and QSTR models. This study suggested that QSIR is useful for estimating the therapeutic index of drug candidates.

Protective action of nicotinic acid benzylamide in a variety of chemically-induced seizures in mice.

PURPOSE: The study aims to assess the anticonvulsant effects offered by benzylamide nicotinic acid (Nic-BZA) in many animal models of chemically-induced seizures (i.e., pentylenetetrazole [PTZ], pilocarpine [PILO], bicuculline [BIC], α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid [AMPA], kainic acid [KA], and N-methyl-d-aspartic acid [NMDA]). Additionally, it analyses side effects of administering Nic-BZA in the form of loss of co-ordination and memory impairment as evaluated in the rotarod and passive avoidance tests, respectively. RESULTS: Antiseizure activity of Nic-BZA was reported in numerous models of chemically-induced seizures and its ED50 value was 37.1mg/kg for PTZ, 53.0mg/kg for AMPA, 81.4mg/kg for BIC, 86.3mg/kg for KA, and 182.6mg/kg for PILO. Moreover, Nic-BZA was totally ineffective (in dosages of up to 200mg/kg) in mice challenged with NMDA-induced seizures. The evaluation of the side effects present shortly after dosing in the rotarod test has revealed neurotoxicity of Nic-BZA with experimentally determined TD50 value of 188.5mg/kg. Protective index (PI) assessment analysis for Nic-BZA has disclosed a substantial difference between the dosage resulting in acute impairment of co-ordination and the dosage resulting in anticonvulsant effect in various chemically evoked seizures, remaining practically ineffective (in dosages of up to 200mg/kg) in mice subjected to the NMDA-induced seizure test. Additionally, Nic-BZA (in dosages of up to 100mg/kg) did not impair long-term memory in mice. CONCLUSIONS: Summing up, Nic-BZA has a wide anticonvulsant effect in different experimental epilepsy models.

Protection provided by Rispens CVI988 vaccine against Marek's disease virus isolates of different pathotypes and early prediction of vaccine take and MD outcome.

We tested the level of protection provided by the Rispens CVI988 (Rispens) vaccine against challenge with a virulent Marek's disease virus (MDV) pathotype (vMDV) and a very virulent pathotype (vvMDV) and the accuracy of a range of predictive measures of Marek's disease (MD) incidence and vaccine take. Commercial layer chicks (n = 236) were vaccinated (or not) with 4000 plaque-forming units (pfu) of Rispens vaccine at hatch and challenged (or not) with 500 pfu of each challenge virus five days post vaccination. The vvMDV pathotype FT158 induced higher MD incidence (65%) and mortality (33%) when compared with the vMDV pathotype MPF57 (39% and 8%, respectively). The protective index provided by the Rispens vaccine against FT158 (61%) did not differ significantly from that against MPF57 (66%). This provides additional evidence that protection provided by the Rispens vaccine is not influenced by pathotype determined in studies using vaccines of other Mardivirus species. The challenge viruses did not differ in MDV or Rispens viral load in spleen at 14 dpc (days post challenge) determined by specific quantitative polymerase chain reaction test. MDV load in peripheral blood leucocytes at 7 and 14 dpc, splenocytes at 14 dpc, feather cells at 14 and 21 dpc and isolator dust at 21 dpc were significant early indicators of subsequent MD incidence to 56 dpc. These are potentially useful as the sampling can be carried out well before the onset of MD and some measures are non-invasive. The Rispens viral load in both invasive and non-invasive samples was more useful as a measure of vaccine take.

Influence of arachidonyl-2'-chloroethylamide, a selective cannabinoid CB1 receptor agonist, on the anticonvulsant and acute side-effect potentials of clobazam, lacosamide, and pregabalin in the maximal electroshock-induced seizure model and chimney test in mice.

The influence of arachidonyl-2'-chloroethylamide (ACEA - a selective cannabinoid CB1 receptor agonist) on the anticonvulsant potency and acute adverse-effect potentials of clobazam, lacosamide, and pregabalin was determined in the maximal electroshock-induced seizure model and chimney test in mice. ACEA (2.5 mg/kg, i.p.) significantly enhanced the anticonvulsant potency of pregabalin in the mouse maximal electroshock-induced seizure model by decreasing the median effective dose (ED50 ) of pregabalin from 125.39 to 78.06 mg/kg (P < 0.05). In contrast, ACEA (2.5 mg/kg) had no significant impact on the anticonvulsant potency of clobazam and lacosamide in the mouse maximal electroshock-induced seizure model. On the other hand, ACEA (2.5 mg/kg) did not affect acute adverse effects of clobazam, lacosamide or pregabalin, and the median toxic doses (TD50 ) for the studied anti-epileptic drugs in combination with ACEA did not differ from the TD50 values as determined for the drugs administered alone in the chimney test. In conclusion, ACEA ameliorates the pharmacological profile of pregabalin, when considering both the anticonvulsant and the acute adverse effects of the drug in preclinical study on animals. The combination of pregabalin with ACEA can be of pivotal importance for patients with epilepsy as a potentially advantageous combination if the results from this study translate into clinical settings.

A combined vaccine against Brucella abortus and infectious bovine rhinotracheitis.

The present study was undertaken to study the immune response in calves vaccinated with Brucella abortus strain 19, infectious bovine rhinotracheitis (IBR) vaccines in monovalent form and combined vaccine containing both antigen. The seroconversion of monovalent and combined vaccines was tested in seronegative cattle calves. IBR vaccine alone and combination with live Brucella abortus S19 vaccine elicited an anamnestic response on day 60 post booster but started declining from day 90 onwards against IBR. B. abortus S19 alone and in combination with IBR vaccine gave more than 2 log protection in mice two weeks post challenge. Fluorescence polarization assay analysis with sera samples of calves vaccinated with B. abortus S19 monovalent vaccine alone and in combination with IBR vaccine revealed the presence of B. abortus antibodies. The components of the combined vaccine did not show any evidence of interference in the development of immunity. This combined vaccine may provide economical and affordable biological for the control of brucellosis and IBR.