Effect of Different Numbers of Interset Antagonist Proprioceptive Neuromuscular Facilitation Stretching on the Total Number of Repetitions for the Agonists.

Recent studies have observed that stretching applied to antagonist muscles can promote improvement in agonist muscle performance. The purpose of this study was to investigate the effect of different numbers of interset proprioceptive neuromuscular facilitation (PNF) stretching for the antagonists on the total number of repetitions completed for the agonists (quadriceps) in the leg extension exercise. Fourteen physically active individuals (age: 29.35 ± 10.5 years; body mass: 79.1 ± 11.34 kg; height: 170.4 ± 8.7 cm) participated in this study. The following experimental protocols were performed: 1) Traditional protocol (Traditional) - without previous stretching; 2) PNF with lesser duration (PNF1-3 sets of 20 secs.); 3) PNF with greater duration (PNF2-3 sets of 30 secs.). Within the experimental protocols (PNF1 and PNF2), stretching exercises for the antagonists were performed before and between the four sets of the unilateral leg extension exercise. All tests were performed on the dominant limb only. The results showed that there was a significant difference in the total number of repetitions for the PNF2 protocol versus the Traditional protocol (p = 0.026). However, there was no significant difference between the PNF1 protocol versus the Traditional protocol (p = 0.577). In conclusion, in the leg extension exercise, an extended duration of interset PNF stretching for the hamstrings, promoted greater contractile performance for the quadriceps as demonstrated by significantly greater total repetitions over four sets.

Examining the Effect of Charged Lipids on Mitochondrial Outer Membrane Dynamics Using Atomistic Simulations.

The outer mitochondrial membrane (OMM) is involved in multiple cellular functions such as apoptosis, inflammation and signaling via its membrane-associated and -embedded proteins. Despite the central role of the OMM in these vital phenomena, the structure and dynamics of the membrane have regularly been investigated in silico using simple two-component models. Accordingly, the aim was to generate the realistic multi-component model of the OMM and inspect its properties using atomistic molecular dynamics (MD) simulations. All major lipid components, phosphatidylinositol (PI), phosphatidylcholine (PC), phosphatidylethanolamine (PE), and phosphatidylserine (PS), were included in the probed OMM models. Because increased levels of anionic PS lipids have potential effects on schizophrenia and, more specifically, on monoamine oxidase B enzyme activity, the effect of varying the PS concentration was explored. The MD simulations indicate that the complex membrane lipid composition (MLC) behavior is notably different from the two-component PC-PE model. The MLC changes caused relatively minor effects on the membrane structural properties such as membrane thickness or area per lipid; however, notable effects could be seen with the dynamical parameters at the water-membrane interface. Increase of PS levels appears to slow down lateral diffusion of all lipids and, in general, the presence of anionic lipids reduced hydration and slowed down the PE headgroup rotation. In addition, sodium ions could neutralize the membrane surface, when PI was the main anionic component; however, a similar effect was not seen for high PS levels. Based on these results, it is advisable for future studies on the OMM and its protein or ligand partners, especially when wanting to replicate the correct properties on the water-membrane interface, to use models that are sufficiently complex, containing anionic lipid types, PI in particular.

A partial least squares and artificial neural network study for a series of arylpiperazines as antidepressant agents.

Depression affects more than 300 million people around the world and can lead to suicide. About 30% of patients on treatment for depression drop out of therapy due to side effects or to latency time associated to therapeutic effects. 5-HT receptor, known as serotonin, is considered the key in depression treatment. Arylpiperazine compounds are responsible for several pharmacological effects and are considered as ligands in serotonin receptors, such as the subtype 5-HT2a. Here, in silico studies were developed using partial least squares (PLSs) and artificial neural networks (ANNs) to design new arylpiperazine compounds that could interact with the 5-HT2a receptor. First, molecular and electronic descriptors were calculated and posteriorly selected from correlation matrixes and genetic algorithm (GA). Then, the selected descriptors were used to construct PLS and ANN models that showed to be robust and predictive. Lastly, new arylpiperazine compounds were designed and their biological activity values were predicted by both PLS and ANN models. It is worth to highlight compounds G5 and G7 (predicted by the PLS model) and G3 and G15 (predicted by the ANN model), whose predicted pIC50 values were as high as the three highest values from the arylpiperazine original set studied here. Therefore, it can be asserted that the two models (PLS and ANN) proposed in this work are promising for the prediction of the biological activity of new arylpiperazine compounds and may significantly contribute to the design of new drugs for the treatment of depression.

Human Dendritic Cells: Their Heterogeneity and Clinical Application Potential in Cancer Immunotherapy.

Dendritic cells (DC) are professional antigen presenting cells, uniquely able to induce naïve T cell activation and effector differentiation. They are, likewise, involved in the induction and maintenance of immune tolerance in homeostatic conditions. Their phenotypic and functional heterogeneity points to their great plasticity and ability to modulate, according to their microenvironment, the acquired immune response and, at the same time, makes their precise classification complex and frequently subject to reviews and improvement. This review will present general aspects of the DC physiology and classification and will address their potential and actual uses in the management of human disease, more specifically cancer, as therapeutic and monitoring tools. New combination treatments with the participation of DC will be also discussed.

New consensus multivariate models based on PLS and ANN studies of sigma-1 receptor antagonists.

The treatment of neuropathic pain is very complex and there are few drugs approved for this purpose. Among the studied compounds in the literature, sigma-1 receptor antagonists have shown to be promising. In order to develop QSAR studies applied to the compounds of 1-arylpyrazole derivatives, multivariate analyses have been performed in this work using partial least square (PLS) and artificial neural network (ANN) methods. A PLS model has been obtained and validated with 45 compounds in the training set and 13 compounds in the test set (r2training = 0.761, q2 = 0.656, r2test = 0.746, MSEtest = 0.132 and MAEtest = 0.258). Additionally, multi-layer perceptron ANNs (MLP-ANNs) were employed in order to propose non-linear models trained by gradient descent with momentum backpropagation function. Based on MSEtest values, the best MLP-ANN models were combined in a MLP-ANN consensus model (MLP-ANN-CM; r2test = 0.824, MSEtest = 0.088 and MAEtest = 0.197). In the end, a general consensus model (GCM) has been obtained using PLS and MLP-ANN-CM models (r2test = 0.811, MSEtest = 0.100 and MAEtest = 0.218). Besides, the selected descriptors (GGI6, Mor23m, SRW06, H7m, MLOGP, and µ) revealed important features that should be considered when one is planning new compounds of the 1-arylpyrazole class. The multivariate models proposed in this work are definitely a powerful tool for the rational drug design of new compounds for neuropathic pain treatment. Graphical abstract Main scaffold of the 1-arylpyrazole derivatives and the selected descriptors.

Characteristics of resistance and virulence factors in different species of coagulase-negative staphylococci isolated from milk of healthy sheep and animals with subclinical mastitis.

Coagulase-negative staphylococci (CNS) are among the main responsible agents for mastitis in sheep. Cure rates can be reduced due to several causes, such as those related to virulence factors presented by microorganisms. This study aims at characterizing the virulence and resistance factors to antimicrobial agents in different CNS species isolated from sheep milk. After collecting milk samples, the samples were analyzed and the CNS species were identified. After identification, the susceptibility-sensitivity profile was examined using the disk diffusion technique for 10 antimicrobial agents. The DNA was extracted to detect the presence of the mecA gene, biofilm (icaADBC, bap, and bhp) and toxin genes (sea, seb, sec, sed, tst, and luk-PV) by PCR. Samples carrying toxin genes had their expression assessed using the reverse-transcription PCR technique. The biofilm production was assessed using the adherence method on a polystyrene plate. One hundred twelve CNS samples were isolated, 53 (47.3%) from animals with subclinical mastitis and 59 (52.7%) from healthy animals. Drugs tested have shown to be efficient for most CNS samples. The largest resistance percentage of CNS was found for the penicillin (17.0%) and tetracycline (10.7%) and 4 samples carried the mecA gene. As for the biofilm genes, the icaADBC operon was found in 10 (8.9%) samples, the bap gene was found in 16 (14.3%), and the bhp gene was found in 3 (2.7%). In addition, 69 (61.6%) samples produced biofilm. The survey of toxin genes has shown that 70 (62.5%) samples showed some toxin-encoding gene. However, none of the samples has expressed any of the genes from those toxins studied.

Synthesis and characterization of catalysts based on mesoporous silica partially hydrophobized for technological applications.

In this work, mesoporous silica mobil composition of matter no. 41 (MCM-41) was synthesized by the sol-gel method. Two different surface modifications were made to transform this material into a very active adsorbent and catalyst support: (i) impregnation of iron nanoparticles and (ii) hydrophobization via chemical vapor deposition (CVD) with ethanol. The materials prepared with different iron contents, i.e., 2.5, 5, and 10 %, after hydrophobization, were characterized by several techniques. CHN analysis and Raman spectroscopy proved that approximately 15 % of carbon is deposited during CVD process mainly as organized carbonaceous structures. The specific surface area was determined by the BET method as up to 1080 m2 g-1, which explains the excellent results of the materials in the adsorption of model dyes methylene blue and indigo carmine. Mössbauer spectroscopy, thermogravimetric (TG)/DTG analysis, and transmission electron microscopy (TEM) images showed that the iron supported may be partially reduced during the CVD process to Fe2+ species, which are stabilized by the carbon coating. This iron species plays an important role in the oxidation of different contaminants, such as quinoline and methylene blue. The results obtained in the catalytic tests showed to be very promising.

Clonal profile, virulence and resistance of Staphylococcus aureus isolated from sheep milk.

The objective of this study was to characterize the clonal profile, virulence factors and antimicrobial resistance, particularly oxacillin resistance, of Staphylococcus aureus isolated from sheep milk. Milk samples were collected from all teats for the California Mastitis Test (CMT), somatic cell count, identification of S. aureus, investigation in these strains of genes encoding toxins (sea, seb, sec, sed, tst), biofilm (icaA, icaC, icaD, bap), leukocidin (luk-PV) oxacillin resistance by mecA gene detection and susceptibility testing (12 antibiotics). Messenger RNA expression was evaluated by RT-PCR in isolates carrying toxin and biofilm genes. Biofilm formation was also evaluated phenotypically by adherence to polystyrene plates. The clonal profile of S. aureus was investigated by pulsed-field gel electrophoresis. A total of 473 milk samples were collected from 242 animals on three farms and 20 S. aureus strains were isolated and none carried the mecA gene. The two sec gene-positive isolates and the isolates carrying the tst and luk-PV genes were positive by RT-PCR. Staphylococcus aureus isolated from the three flocks studied showed high susceptibility to the drugs tested and none was biofilm producer, indicating that biofilm formation was not a virulence factor causing infection by these strains. The typing of 17 S. aureus isolates revealed the presence of a common clone on the three farms studied, and the presence and expression of the sec and tst genes in one strain of this clone suggest the possible acquisition of virulence genes by this clone, a fact that is important for animal health and food hygiene.

Clonal profile, virulence and resistance of Staphylococcus aureus isolated from sheep milk

The objective of this study was to characterize the clonal profile, virulence factors and antimicrobial resistance, particularly oxacillin resistance, of Staphylococcus aureus isolated from sheep milk. Milk samples were collected from all teats for the California Mastitis Test (CMT), somatic cell count, identification of S. aureus, investigation in these strains of genes encoding toxins (sea, seb, sec, sed, tst), biofilm (icaA, icaC, icaD, bap), leukocidin (luk-PV) oxacillin resistance by mecA gene detection and susceptibility testing (12 antibiotics). Messenger RNA expression was evaluated by RT-PCR in isolates carrying toxin and biofilm genes. Biofilm formation was also evaluated phenotypically by adherence to polystyrene plates. The clonal profile of S. aureus was investigated by pulsed-field gel electrophoresis. A total of 473 milk samples were collected from 242 animals on three farms and 20 S. aureus strains were isolated and none carried the mecA gene. The two sec gene-positive isolates and the isolates carrying the tst and luk-PV genes were positive by RT-PCR. Staphylococcus aureus isolated from the three flocks studied showed high susceptibility to the drugs tested and none was biofilm producer, indicating that biofilm formation was not a virulence factor causing infection by these strains. The typing of 17 S. aureus isolates revealed the presence of a common clone on the three farms studied, and the presence and expression of the sec and tst genes in one strain of this clone suggest the possible acquisition of virulence genes by this clone, a fact that is important for animal health and food hygiene.

Design of inhibitors of thymidylate kinase from Variola virus as new selective drugs against smallpox.

Recently we constructed a homology model of the enzyme thymidylate kinase from Variola virus (VarTMPK) and proposed it as a new target to the drug design against smallpox. In the present work, we used the antivirals cidofovir and acyclovir as reference compounds to choose eleven compounds as leads to the drug design of inhibitors for VarTMPK. Docking and molecular dynamics (MD) studies of the interactions of these compounds inside VarTMPK and human TMPK (HssTMPK) suggest that they compete for the binding region of the substrate and were used to propose the structures of ten new inhibitors for VarTMPK. Further docking and MD simulations of these compounds, inside VarTMPK and HssTMPK, suggest that nine among ten are potential selective inhibitors of VarTMPK.

Molecular modeling studies of Yersinia pestis dihydrofolate reductase.

Considering the risk represented by plague today as a potential biological warfare agent, we propose cytosolic Yersinia pestis dihydrofolate reductase (YpDHFR) as a new target to the design of selective plague chemotherapy. This enzyme has a low homology with the human enzyme and its crystallographic structure has been recently deposited in the Protein Data Bank (PDB). Comparisons of the docking energies and molecular dynamic behaviors of five known DHFR inhibitors inside a 3D model of YpDHFR (adapted from the crystallographic structure) and human DHFR (HssDHFR), revealed new potential interactions and suggested insights into the design of more potent HssDHFR inhibitors as well as selective inhibitors for YpDHFR.

Docking studies on the binding of quinoline derivatives and hematin to Plasmodium falciparum lactate dehydrogenase.

The literature has reported that ferriprotoporphyrin IX (hematin) intoxicates the malarial parasite through competition with NADH for the active site of the enzyme lactate dehydrogenase (LDH). In order to avoid this, the parasite polymerizes hematin to hemozoin. The quinoline derivatives are believed to form complexes with dimeric hematin, avoiding the formation of hemozoin and still inhibiting LDH. In order to investigate this hypothesis we calculated the docking energies of NADH and some quinoline derivatives (in the free forms and in complex with dimeric hematin) in the active site of the Plasmodium falciparum LDH (PfLDH). Ours results showed better docking score values to the complexes when compared to the free compounds, pointing them as more efficient inhibitors of Pf_LDH. Further we performed Molecular Dynamics (MD) simulations studies on the best docking conformation of the complex chloroquine-dimeric hematin with PfLDH. Our in silico results corroborate experimental data suggesting a possible action route for the quinoline derivatives in the inhibition of PfLDH.

Analysis of Bacillus anthracis nucleoside hydrolase via in silico docking with inhibitors and molecular dynamics simulation.

As the enzyme nucleoside hydrolase (NH) is widely found in nature but has not yet been detected in mammals, it is considered an ideal target in the development of chemotherapy against parasitic diseases and bacterial infections like anthrax. Considering the risk that this biological warfare agent represents nowadays, the search for new drugs and new molecular targets in the development of chemotherapy against anthrax is imperative. On this basis, we performed docking studies of six known NH inhibitors at the active site of NH from Bacillus anthracis (BaNH). Subsequently, molecular dynamics (MD) simulations of these compounds inside BaNH were carried out in order to complement the docking studies and select the most promising compounds as leads for the design of potential BaNH inhibitors. Most of the docking and MD results obtained agreed well with each other and showed good correlation with experimental data.

Design of new chemotherapeutics against the deadly anthrax disease. Docking and molecular dynamics studies of inhibitors containing pyrrolidine and riboamidrazone rings on nucleoside hydrolase from Bacillus anthracis.

Anthrax is a disease caused by Bacillus anthracis, a dangerous biological warfare agent already used for both military and terrorist purposes. An important selective target for chemotherapy against this disease is nucleoside hydrolase (NH), an enzyme still not found in mammals. Having this in mind we have performed molecular docking studies, aiming to analyze the three-dimensional positioning of six known inhibitors of Trypanosoma vivax NH (TvNH) in the active site of B. anthracis NH (BaNH). We also analyzed the main interactions of these compounds with the active site residues of BaNH and the relevant factors to biological activity. These results, together with further molecular dynamics (MD) simulations, pointed out to the most promising compounds as lead for the design of potential inhibitors of BaNH. Most of the docking and MD results obtained corroborated to each other. Additionally, the docking results also suggested a good correlation with experimental data.

Molecular modeling of Mycobacterium tuberculosis DNA gyrase and its molecular docking study with gatifloxacin inhibitors.

Mycobacterium tuberculosis (Mt) is a leading cause of infectious disease in the world today. This outlook is aggravated by a growing number of Mt infections in individuals who are immunocompromised as a result of HIV infections. Thus, new and more potent anti-tuberculosis agents are necessary. Therefore, DNA gyrase was selected as a target enzyme to combat Mt. In this work, the first three-dimensional molecular model of the hypothetical structures for the Mycobacterium tuberculosis DNA gyrase (mtDNAg) was elucidated by a homology modeling method. In addition, the orientations and binding affinities of some gatifloxacin analogs with those new structures were investigated. Our findings could be helpful for the design of new more potent gatifloxacin analogs.

CSC, an adenosine A(2A) receptor antagonist and MAO B inhibitor, reverses behavior, monoamine neurotransmission, and amino acid alterations in the 6-OHDA-lesioned rats.

The present work showed the effects of 8-(-3-chlorostyryl)-caffeine (CSC), an A(2A) receptors antagonist and MAO B inhibitor, on behavior and biochemical alterations in 6-OHDA-lesioned rats. Male Wistar rats (280 g) were injected with CSC (1 and 5 mg/kg, i.p.) alone or combined with l-DOPA (50 mg/kg+benserazide 12.5 mg/kg), starting 6 days after the striatal 6-OHDA lesions, and once daily for the next 7 days. Fourteen days after the 6-OHDA lesion (and 24 h after CSC or vehicle), the number of net body rotations/h (after the apomorphine challenge) was recorded and, at the next day, animals were sacrificed. The ipsilateral striatum was used for HPLC measurements of monoamines and amino acids or for determination of nitrite contents and lipid peroxidation. Results showed that the increase in body rotation, induced by the 6-OHDA lesion, after the apomorphine challenge, was significantly and dose-dependently reversed by CSC. Furthermore, the decreased striatal levels of DA and metabolites, in the 6-OHDA-lesioned rats, were reversed after CSC treatment, and these effects were potentiated after the combination with l-DOPA. Similar results were observed with NE, 5-HT and 5-HIAA. While glutamate and GABA were increased in the 6-OHDA-lesioned group, CSC alone or mainly combined with l-DOPA reversed these alterations. In addition, the CSC treatment of 6-OHDA-lesioned rats reversed the increased nitrite formation and lipid peroxidation induced by 6-OHDA. In conclusion, CSC by means of its dual action as A(2A) antagonist and MAO-B inhibitor reversed behavior and biochemical alterations, observed in the 6-OHDA-lesioned rats, pointing out to its potential benefit for the treatment of PD.

Neuroprotective effects of caffeine in the model of 6-hydroxydopamine lesion in rats.

The work shows the effects of caffeine after the intrastriatal injection of 6-OHDA in rats, considered as a model of Parkinson disease (PD). Two weeks after the 6-OHDA lesion, rats exhibit a characteristic rotation behavior as a response to the apomorphine challenge. Our results showed significant increases in the number of apomorphine-induced rotations in 6-OHDA-lesioned rats, as compared to sham-operated animals. A partial recovery was observed in 6-OHDA-lesioned rats, after caffeine (10 and 20 mg/kg, i.p., daily for 14 days) treatment. The stereotaxic injection of 6-OHDA produced loss of striatal neurons, as indicated by the decrease in monoamines levels, in the ipsilateral side (75-85%) when compared to the contralateral side. Significant decreases in noradrenaline levels were seen in the ipsilateral side of 6-OHDA group (62%), and this effect was not significantly reversed in caffeine-treated groups. While significant decreases in dopamine levels were seen in the ipsilateral side of 6-OHDA group (78%), in the caffeine-treated group (10 and 20 mg/kg, i.p.) the decreases were only 53 and 18%, indicating significant recoveries. In conclusion, our data demonstrated beneficial effects of caffeine in this model of PD, suggesting the potential use of A2A antagonists as a novel treatment for this neurodegenerative disease.

Antioxidant effect of nimodipine in young rats after pilocarpine-induced seizures.

Nimodipine (ND) is a centrally active calcium antagonist that blocks the voltage-dependent L-type channels. Its antiepileptic properties have been proved in various animal models, including pilocarpine-induced seizures in adult rats. In order to investigate protective effects of the ND (10 (ND10) and 30 mg/kg (ND30), i.p.), young male rats (21-day-old) received ND injections before pilocarpine administration (400 mg/kg, s.c., pilocarpine group (P400)). The pretreatment with ND10 and ND30 prolonged the latencies of seizures and death on this seizure model. ND pretreatment in two doses decreased the levels of lipid peroxidation when compared to pilocarpine group. The P400 administration increased the striatal catalase activity. However, the administration of ND, in dose of 30 mg/kg, 30 min before pilocarpine, preserved catalase activity in normal levels. On the other hand, no change was detected in the animals treated with the dose of 10 mg/kg. Our results confirm the neuroprotective effect of ND on the seizures in young rats, suggesting that this drug acts positively on lipid peroxidation. Our observations shows that nimodipine cannot induces these effects via blockade of Ca(2+)-channel.

Pilocarpine-induced seizures in adult rats: monoamine content and muscarinic and dopaminergic receptor changes in the striatum.

High doses of the muscarinic cholinergic agonist pilocarpine are a useful model for investigation of the essential mechanisms for seizure generation and spread in rodents. Pilocarpine (400 mg/kg; subcutaneously) was administered in 2-month-old female rats, and the content of striatum monoamines and (M(1)+M(2)) muscarinic and D(2) dopaminergic receptors was measured in the acute period. All treated animals showed peripheral cholinergic signs, stereotyped and clonic movements, tremors, seizures and the percentage mortality was approximately 63%. High performance liquid chromatography determinations, performed 24 h later, showed a decrease of striatal levels of dopamine, dihydroxyphenylacetic acid, 4-hydroxy-3-methoxy-phenylacetic acid and 5-hydroxytryptamine. Pilocarpine treatment induced downregulation of (M(1)+M(2)) muscarinic receptors and reduced the dissociation constants of (M(1)+M(2)) muscarinic and D(2) dopaminergic receptors, suggesting that these systems exert opposite effects on the regulation of convulsive activity. These and other important neurochemical changes found in the course of establishment of an epileptic focus can be observed after status epilepticus induced by pilocarpine.

Attenuating effects of melatonin on pilocarpine-induced seizures in rats.

Daily melatonin (10-50 mg/kg, i.p.) treatment at 08.30 h or 17.00 h for 1 week of female rats (2-months-old) increased the latency to the appearance of the first convulsion in the pilocarpine-induced seizure model. Other behavior parameters remained unaltered. The anticonvulsant effect of melatonin seemed to be more intense at the light-dark transition. Moreover, the effect of repeated melatonin treatment was also age-related, since it showed a lower threshold in 2-month-old than in 21-day-old rats, and the acute treatment was not efficient. [3H]N-methylscopolamine binding was unaltered in the hippocampus and striatum of adult rats after the association of melatonin and pilocarpine. While muscarinic binding was unaltered in adult rats, it increased in the hippocampus of young rats in the presence of melatonin (50 mg/kg) and pilocarpine, and did not change in the striatum. Melatonin partially recovered [3H]GABA binding in the hippocampus in the presence of pilocarpine-induced seizures, and intensified pilocarpine effects in the striatum of adult rats.