Whole-body vibration mediates mechanical hypersensitivity through Aβ-fiber and C-fiber thermal sensation in a chronic pain model

Whole-body vibration (WBV), which is widely used as a type of exercise, involves the use of vibratory stimuli and it is used for rehabilitation and sports performance programmes. This study aimed to investigate the effect of WBV treatment in a chronic pain model after 10 WBV sessions. An animal model (chronic pain) was applied in 60 male Wistar rats (±180 g, 12 weeks old) and the animals were treated with low intensity exercise (treadmill), WBV (vibrating platform), and a combined treatment involving both. The controls on the platform were set to a frequency of 42 Hz with 2 mm peak-to-peak displacement, g ≈ 7, in a spiral mode. Before and after the vibration exposure, sensitivity was determined. Aβ-fibers-mediated mechanical sensitivity thresholds (touch-pressure) were measured using a pressure meter. C-fibers-mediated thermal perception thresholds (hot pain) were measured with a hot plate. After each session, WBV influenced the discharge of skin touch-pressure receptors, reducing mechanical sensitivity in the WBV groups (P < 0.05). Comparing the conditions “before vs. after”, thermal perception thresholds (hot pain) started to decrease significantly after the third WBV session (P < 0.05). WBV decreases mechanical hyperalgesia after all sessions and thermal sensitivity after the third session with the use of WBV.     

Synthetic Aurones: New Features for Schistosoma mansoni Therapy

In this work, two synthetic aurones revealed moderate schistosomicidal potential in in vitro and in vivo assays. Aurones ( 1 ) and ( 2 ) promoted changes in tegument integrity and motor activity, leading to death of adult Schistosoma mansoni worms in in vitro assays. When administered orally (two doses of 50 mg/kg) in experimentally infected animals, synthetic aurones ( 1 ) and ( 2 ) promoted reductions of 56.20 % and 57.61 % of the parasite load and stimulated the displacement towards the liver of the remaining adult worms. The oogram analysis revealed that the treatment with both aurones interferes with the egg development kinetics in the intestinal tissue. Seeking an action target for compounds ( 1 ) and ( 2 ), the connection with NTPDases enzymes, recognized as important therapeutic targets for S. mansoni, was evaluated. Molecular docking studies have shown promising results. The dataset reveals the anthelmintic character of these compounds, which can be used in the development of new therapies for schistosomiasis.     

Computer-Guided Trypanocidal Activity of Natural Lactones Produced by Endophytic Fungus of Euphorbia umbellata

Hundreds of millions of people worldwide are affected by Chagas’ disease caused by Trypanosoma cruzi. Since the current treatment lack efficacy, specificity, and suffers from several side-effects, novel therapeutics are mandatory. Natural products from endophytic fungi have been useful sources of lead compounds. In this study, three lactones isolated from an endophytic strain culture were in silico evaluated for rational guidance of their bioassay screening. All lactones displayed in vitro activity against T. cruzi epimastigote and trypomastigote forms. Notably, the IC₅₀ values of (+)-phomolactone were lower than benznidazole (0.86 vs. 30.78 μM against epimastigotes and 0.41 vs. 4.88 μM against trypomastigotes). Target-based studies suggested that lactones displayed their trypanocidal activities due to T. cruzi glyceraldehyde-3-phosphate dehydrogenase (TcGAPDH) inhibition, and the binding free energy for all three TcGAPDH-lactone complexes suggested that (+)-phomolactone has a lower score value (−3.38), corroborating with IC₅₀ assays. These results highlight the potential of these lactones for further anti-T. cruzi drug development.     

Can the use of zooplankton dormant stages from natural wetlands contribute to restoration of mined wetlands?

Wetlands are among the most diverse environments on the planet and are strongly threatened by human activities. Their restoration and/or mitigation of human impacts, therefore, relies on information that can aid to the management of impacted wetlands so that they return to a (semi-) natural state. We investigate in this study the relationship between dormant stages of zooplankton and clay removal in areas subjected to mining. We evaluate whether a gradual increase in topsoil addition from donor natural wetlands to the sediment of mined wetlands influenced the zooplankton community. Eight wetlands were sampled in the Sinos River floodplain, four natural and four mined. In the laboratory, four field sediment samples were incubated for zooplankton hatching in five treatments comprising sediments from: mined wetlands, natural wetlands, and three treatments containing mined sediments added with low (5%), medium (20%) and high (40%) quantities of sediment from natural wetlands. Hatching consisted of 61 individuals distributed across eight zooplankton taxa. Copepod nauplii were the most abundant (31.1%) followed by Epiphanes sp. (29.5%) and Ovalona glabra (16.4%). While natural wetlands provided 42.6% of the hatched zooplankton, mined wetlands had just 6.5%. Zooplankton richness and abundance were higher in natural wetland sediments compared with mined and added sediment wetlands. To some degree, the sediment soil donation from natural to mined wetlands was considered viable. As long as prior studies are performed to test the size and quality of the dormant banks present in the sediment of candidate donor wetlands, sediment from donor wetlands may aid in the establishment of a more diverse community in disturbed systems.

     

Lipopolysaccharide reduces urethral smooth muscle contractility via cyclooxygenase activation

Journal of Physiology and Biochemistry - Lipopolysaccharide (LPS) is a component of gram-negative bacteria wall that elicits inflammatory response in the host through the toll-like receptor 4...     

The citrus plant pathogen Xanthomonas citri has a dual polyamine-binding protein

ATP-Binding Cassette transporters (ABC transporters) are protein complexes involved in the import and export of different molecules, including ions, sugars, peptides, drugs, and others. Due to the diversity of substrates, they have large relevance in physiological processes such as virulence, pathogenesis, and antimicrobial resistance. In Xanthomonas citri subsp. citri, the phytopathogen responsible for the citrus canker disease, 20% of ABC transporters components are expressed under infection conditions, including the putative putrescine/polyamine ABC transporter, PotFGHI. Polyamines are ubiquitous molecules that mediate cell growth and proliferation and play important role in bacterial infections. In this work, we characterized the X. citri periplasmic-binding protein PotF (XAC2476) using bioinformatics, biophysical and structural methods. PotF is highly conserved in Xanthomonas sp. genus, and we showed it is part of a set of proteins related to the import and assimilation of polyamines in X. citri. The interaction of PotF with putrescine and spermidine was direct and indirectly shown through fluorescence spectroscopy analyses, and experiments of circular dichroism (CD) and small-angle X-ray scattering (SAXS), respectively. The protein showed higher affinity for spermidine than putrescine, but both ligands induced structural changes that coincided with the closing of the domains and increasing of thermal stability.     

Bilateral impairments of shoulder abduction in chronic hemiparesis: Electromyographic patterns and isokinetic muscle performance

ObjectiveTo analyze electromyographic (EMG) patterns and isokinetic muscle performance of shoulder abduction movement in individuals who sustained a cerebrovascular accident (CVA).DesignTwenty-two individuals who sustained a CVA and 22 healthy subjects volunteered for EMG activity and isokinetic shoulder abduction assessments. EMG onset time, root mean square (RMS) for upper trapezius and deltoid muscles, as well as the isokinetic variables of peak torque, total work, average power and acceleration time were compared between limbs and groups.ResultsThe paretic side showed a different onset activation pattern in shoulder abduction, along with a lower RMS for both muscles (21.8 ± 13.4% of the maximal voluntary isometric contraction (MVIC) for the deltoid and 25.9 ± 15.3% MVIC for the upper trapezius, about 50% lower than the control group). The non-paretic side showed a delay in both muscles activation and a lower RMS for the deltoid (32.2 ± 13.7% MVIC, about 25% lower than the control group). Both sides of the group of individuals who sustained a CVA presented a significantly lower isokinetic performance compared to the control group (paretic side ～60% lower; non-paretic side ～35% lower).ConclusionsShoulder abduction muscle performance is impaired in both paretic and non-paretic limbs of individuals who sustained a CVA.     

Muscle fatigue and metabolic responses following three different antagonist pre-load resistance exercises

PurposePreload of antagonist muscles can be achieved by reciprocal actions (RAs) or by opposing muscle actions. However, evidence concerning neuromuscular and fatigue responses are scarce.ObjectiveTo compare the effects of different knee flexor (KF) preload methods on knee extension (KE) vastus medialis muscle fatigue, based on EMG-spectral index (FI), load range (LR), total work (TW), blood lactate (LAC) and biceps femoris co-activation (BFc) during resistance exercise.MethodsTwenty-four healthy men (23.5 ± 3.6 yrs) performed three antagonist pre-load isokinetic exercises (4 sets, 10 repetitions, 60° s^?1, 1 min rest between sets): RA (KF contraction immediately followed by KE); Superset (SS; one KF set immediately followed by one KE set); Multiple Set (MS; four KF sets followed by four KE sets).ResultsTotal work was significantly greater in RA. There was no significant decrease in LR between sets in RA. The BFc did not differ between protocols (p = 0.063). However, RA presented greater biceps femoriscoactivation. The FI was greater during SS compared to RA and MS (p < 0.05). The SS had greater LAC when compared to MS and RA (p = 0.005 and p = 0.007, respectively).ConclusionIt is suggested that the RA protocol is more neuromuscular and metabolic efficient during the performance of knee extension resistance exercise.     

Mechanics of the maxillary central incisor. Influence of the periodontal ligament represented by beam elements

This study aimed to evaluate the influence of loading on a maxillary central incisor with the periodontal ligament (PDL) represented by 2D elastic beam elements using a 2D finite element analysis. Two models (M) were built varying the PDL representation: Mh (homogeneous PDL) and Mht (heterogeneous PDL with beam3 elements). Stress and displacements were determined for three loading conditions (L): Ll, lingual face loading at 45° with the tooth long axis; Li, perpendicular to the incisal edge; and Lip, on the incisal edge, parallel to the tooth long axis. Evaluation was performed on ANSYS software. Lip provided lower stress variation on the tooth and support structures when compared to Ll and Li. PDL's influence on stress values was lower for Lip. Oblique loading showed stress and displacement not observed in parallel loading condition through PDL's heterogeneous representation and it is probably incompatible with the in vivo condition.     

Vinpocetine attenuates the metabolic dysfunction induced by amyloid β-peptides in PC12 cells

The cytoprotective effect of vinpocetine [14-ethoxycarbonyl-(3α,16α-ethyl)-14,15-eburnamine] was investigated on PC12 cells treated with the amyloid β-peptides (Aβ) for 24 hours. Vinpocetine was shown to protect cells from the inhibition in redox status induced by exposure to Aβ_25–35 and Aβ_1–40, the maximal protection being achieved at a vinpocetine concentration of 40 μM. At this concentration, vinpocetine blocked the inhibition of the mitochondrial respiratory chain complexes II–III and IV and completely abolished the depletion of pyruvate levels induced by toxic concentrations of Aβ peptides. Furthermore, the accumulation of ROS in cells exposed to Aβ_25–35 and Aβ_1–40 evaluated using the fluorescent probe 2′,7′-dichlorofluorescin (DCF), was reduced in the presence of 40 μM vinpocetine. Taken together, the data presented herein demonstrate that vinpocetine protects cells from Aβ toxicity, preventing the generation of oxidative stress due to the excessive accumulation of ROS. This study suggests that vinpocetine can exert neuroprotective properties which might be of importance and contribute to its clinical efficacy in the treatment of Alzheimer's disease or other neurodegenerative disorders in which oxidative stress is involved.