Synthesis,and anticonvulsant activity of new amides derived from 3-methyl- or 3-ethyl-3-methyl-2,5-dioxo-pyrrolidin-1-yl-acetic acids

This paper describes the synthesis of the library of 22 new 3-methyl- and 3-ethyl-3-methyl-2,5-dioxo-pyrrolidin-1-yl-acetamides as potential anticonvulsant agents. The maximal electroshock (MES) and the subcutaneous pentylenetetrazole (scPTZ) seizure models were used for screening all the compounds. The 6 Hz model of pharmacoresistant limbic seizures was applied for studying selected derivatives. Six amides were chosen for pharmacological characterization of their antinociceptive activity in the formalin model of tonic pain as well as local anesthetic activity was assessed in mice. The pharmacological data indicate on the broad spectra of activity across the preclinical seizure models. Compounds 10 (ED₅₀ = 32.08 mg/kg, MES test) and 9 (ED₅₀ = 40.34 mg/kg, scPTZ test) demonstrated the highest potency. These compounds displayed considerably better safety profiles than clinically relevant antiepileptic drugs phenytoin, ethosuximide, or valproic acid. Several molecules showed antinociceptive and local anesthetic properties. The in vitro radioligand binding studies demonstrated that the influence on the sodium and calcium channels may be one of the essential mechanisms of action.     

Synergistic interactions between the antinociceptive effect of Rhodiola rosea extract and B vitamins in the mouse formalin test

AimIn this study, the pharmacological interactions between a Rhodiola rosea ethanol extract and B-vitamins such as thiamine (B₁), riboflavine (B₂), pyridoxine (B₆), cyanocobalamin (B₁₂) and a mixture of vitamins B₁ + B₆ + B₁₂ was investigated in the mouse formalin test.MethodsIndividual dose response curves of the Rhodiola rosea ethanol extract, as well as B-vitamins alone or in a mixture were evaluated in mice in which nociception was induced with 2% formalin intraplantarly. The antinociceptive mechanisms of the Rhodiola rosea were investigated by exploring the role of the opioid and serotonin receptors and the nitric oxide pathway. Isobolographic analysis was used to evaluate the pharmacological interactions between the Rhodiola rosea ethanol extract and each B-vitamin individually or the mixture of vitamins B₁ + B₆ +B₁₂ by using the ED₃₀ and a fixed 1:1 ratio combination.ResultsAdministration of the Rhodiola rosea extract alone or in combination with all of the vitamins produced a significant and dose-dependent antinociceptive response. The antinociceptive effect of the Rhodiola rosea extract (ED₅₀ = 81 mg/kg, p.o.) was significant and reverted in the presence of antagonists of the 5-HT_1A, GABA/BDZs and opioid receptors and by blocking mediators of the nitric oxide/cGMP/K⁺ channels pathway. Isobolograms demonstrate that all of the combinations investigated in this study produced a synergistic interaction experimental ED₃₀ values were significantly smaller than those calculated theoretically.ConclusionsThese results provide evidence that a Rhodiola rosea ethanol extract in combination with B-vitamins produces a significant diminution in the nociceptive response in a synergistic manner, which is controlled by various mechanisms. These findings could aid in the design of clinical studies and suggest that these combinations could be applied for pain therapy.     

Cellular and nephrotoxicity of selenium species

ProjectBeside its useful functions at very low concentrations, selenium including supplementary Se sources pose a potential toxicological risk. The toxicity of selenium species was tested in HaCaT cell culture and related nephrotoxicity in mice.ProcedureThe apoptotic shrinkage and necrotic expansion of cells were measured by time-lapse image microscopy. Acute nephrotoxicity was estimated upon administration of various selenium species to mice for two weeks. To confirm or to refute the accumulation of Se in the kidney and its potential chronic effect, Se concentration in kidney tissue and histopathlology were tested.ResultsThe comparison of selenium species showed that organic lactomicroSe did not affect cell growth at 5 ppm, but inorganic nanoSe severely hampered it at lower concentration (1 ppm). The in vivo Se treatment (0.5, 5, 50 ppm, corresponding to 4, 40 and 400 μg/kg) was misleading as it did neither affect the outward appearance nor the weight of the kidney. Se accumulation was observed after selenate, selenite, SelPlex, selenite and nanoSe administration, while lactomicroSe caused no traceable accumulation. In vivo, ex vivo and in vitro experiments reflected this order of selenium toxicity: selenate > selenite > SelPlex = nanoSe > lactomicroSe.ConclusionWithin the tested species lactomicroSe was the only non-nephrotoxic selenium source recommended for nutritional Se supplementation.     

Antinociceptive activity of swertiamarin isolated from Enicostemma axillare

Many traditional Indian medicinal plants which contain large quantity of a secoiridoid, swertiamarin are being used to relieve pain. Iridoids present in a wide variety of medicinal plants possess a large number of medicinal properties. In the present study in vivo antinociceptive activity of swertiamarin isolated from E. axillare was carried out using three different methods in mice. In the hot plate method, a significant increase in the latency period was observed for the treatment with swertiamarin at 100 and 200 mg/kg bw after 30 and 45 min. The percent protection observed after 45 min was 109.42, 147.42 and 157.14, respectively, for the standard paracetamol and swertiamarin at 100 and 200 mg/kg bw treatments. A significant increase in the tail withdrawal reflex was observed for the swertiamarin treatment at both the doses with percent protections of 150 and 200, respectively. In both these methods, swertiamarin produced potent activity than that of standard paracetamol. In the acetic acid induced writhing, swertiamarin at 100 and 200 mg/kg bw reduced the number of writhes significantly. Dose dependent results were observed in all the three methods and among the two doses, swertiamarin at 200 mg/kg bw showed potent activity. These results prove that swertiamarin possess both peripheral and central antinociceptive activity.     

Electromyographic evaluation of upper limb muscles involved in armwrestling sport simulation during dynamic and static conditions

ObjectiveTo evaluate the electromyographic activity of the Pectoralis Major (PM), Biceps Brachii (BB), Pronator Teres (PT) and Flexor Carpi Ulnaris (FCU) muscles involved in simulated armwrestling.MethodsTen trained volunteers were selected to perform the armwrestling movement, during dynamic tests with 40% and 80% of maximum voluntary load (MVL) and static tests in the initial, intermediary and final positions. Electromyographic and force data were normalized for analyses.ResultsIn dynamic tests with 40% MVL, electric activity of the PT muscle was greater than FCU (p < 0.01) and BB (p < 0.05) muscles, and with 80% MVL, PM and PT muscles were the most active. In static tests, electric activity increased from the initial to final positions for the PM muscle (p < 0.05), while it decreased for the BB and PT muscles (p < 0.001 and p < 0.05, respectively). No significant changes were observed for force and no correlation was found with the simultaneous electric activity.ConclusionsIt can be concluded that the PM and FCU muscles participate as agonists in the simulated armwrestling whereas the BB and PT muscles seem to perform secondary functions. Electric activity showed to be dependent on the load and on the position of the upper limb, but not on the force produced during the movement.     

Improved motor function in dko mice by intravenous transplantation of bone marrow-derived mesenchymal stromal cells

Background aimsWe explored the potential therapeutic value of transplanting bone marrow (BM)-derived mesenchymal stromal cells (MSC) into utrophin/dystrophin-deficient double knock-out (dko) mice, a murine model of Duchenne muscular dystrophyMethodsMSC from male rats were isolated and transplanted into female dko mice via the caudal vein. Behavior and locomotor function were later evaluated, along with the expression of dystrophin and utrophin in the sarcolemma of myofiber tissues. The presence of grafted cells was confirmed via polymerase chain reaction for the sex-determining region of the Y-chromosomeResultsLocomotor activity improved significantly (P < 0.05) from 5 to 15 weeks after cell transplantation, as measured by traction, rotating rod and running wheel tests. We also found that the expression of dystrophin and utrophin increased significantly (P < 0.05) and progressively in the sarcolemma from 5 to 15 weeks after transplantation. The median lifespan of mice in the normal group (74.1 weeks) was significantly (P < 0.001) higher than those in the control (22.0 weeks) and transplantation (35.0 weeks) groups, and the median lifespan of mice in the transplantation group was significantly (P < 0.001) higher than that in the control groupConclusionsResults of this study demonstrate that BM MSC have potential value in xenogeneic transplantation therapy for muscular dystrophy.     

Search for anticonvulsant and analgesic active derivatives of dihydrofuran-2(3H)-one

A series of derivatives of dihydrofuran-2(3H)-one (γ-butyrolactone, GBL) was synthesized and tested for anticonvulsant, neurotoxic and analgesic activity. In the anticonvulsant screening 10 lactones were effective in the maximal electroshock test (MES) at the highest doses (300 and 100 mg/kg, 0.5 h, ip, mice). Statistical analysis showed correlation between the anticonvulsant activity and relative lipophilicity parameters determined by experimental and computational methods (R_M0, C log P and M log P). Preliminary antinociceptive evaluation of selected derivatives revealed strong analgesic activity. The majority of the tested compounds showed high efficacy in animal models of acute pain (hot plate and writhing tests) and strong local anesthetic activity (modified tail immersion test). The obtained ED₅₀ values were comparable with such analgesics as acetylsalicylic acid and morphine.     

Development of a highly sensitive ELISA for aldosterone in mouse urine: Validation in physiological and pathophysiological states of aldosterone excess and depletion

BackgroundClinical studies have established aldosterone as a critical physiological and pathophysiological factor in salt and water homeostasis, blood pressure control and in heart failure. Genetic and physiological studies of mice are used to model these processes. A sensitive and specific assay for aldosterone is therefore needed to monitor adrenocortical activity in murine studies of renal function and cardiovascular diseases.MethodsAntibodies against aldosterone were raised in sheep as previously described. HRP-Donkey-anti-sheep IgG enzyme tracer was produced in our laboratory using the Lightning-Link HRP technique. Aldosterone ELISA protocol was validated and optimised to achieve the best sensitivity. The assay was validated by analysing the urine of mice collected under various experimental conditions designed to stimulate or suppress aldosterone in the presence of other potentially interfering steroid hormones.ResultsCross-reactivity with the steroids most likely to interfere was minimal: corticosterone = 0.0028%, cortisol = 0.0006%, DOC = 0.0048% except for 5α-dihydro-aldosterone = 1.65%. Minimum detection limit of this ELISA was 5.2 pmole/L (1.5 pg/mL). The validity of urinary aldosterone ELISA was confirmed by the excellent correlation between results obtained before and after solvent extraction and HPLC separation step (Y = 1.092X + 0.03, R² = 0.995, n = 54). Accuracy studies, parallelism and imprecision data were determined and all found to be satisfactory. Using this assay, mean urinary aldosterone levels were (i) approximately 60-fold higher in females than males mice; (ii) increased 6-fold by dietary sodium restriction; (iii) increased 10-fold by ACTH infusion and (iv) reduced by >60% in Cyp11b1 null mice.ConclusionWe describe an ELISA for urinary aldosterone that is suitable for repeated non-invasive measurements in mice. Female aldosterone levels are higher than males. Unlike humans, most aldosterone in mouse urine is not conjugated. Increased levels were noted in response to dietary sodium restriction and ACTH treatment. The sensitivity of the assay is sufficient to detect suppressed levels in mouse models of congenital adrenal hyperplasia.     

Mechanical stress regulates osteogenic differentiation and RANKL/OPG ratio in periodontal ligament stem cells by the Wnt/β-catenin pathway

BackgroundThe balance between osteoblastic and osteoclastic activity is critical in orthodontic tooth movement (OTM). Mesenchymal stem cells (MSCs) play an important role in maintaining bone homeostasis, and periodontal ligament stem cells (PDLSCs) are tissue-specific MSCs in the periodontal ligament. However, whether PDLSCs are required for periodontal tissue remodeling during OTM is not fully understood.MethodsHere, we used PDGFRα and Nestin to trace PDLSCs during OTM in rats. We treat human PDLSCs with 100 kpa static pressure for 1 h or 12 h in vitro, and examined the phenotypic changes and expression of RANKL and OPG in these cells.ResultsIn vivo, we found that positive signals of PDGFRα and Nestin in the PDL gradually increased and then decreased on the pressure side to which pressure was applied. In vitro, the osteogenic differentiation of PDLSCs was significantly increased after force treatment for 1 h relative to 12 h. In contrast, the expression ratio of RANKL/OPG was reduced at 1 h and significantly increased at 12 h. Furthermore, we found that the Wnt/β-catenin pathway was dynamically activated in the PDL and in PDLSCs after mechanical stimulation. Importantly, the canonical Wnt pathway inhibitor DKK1 blocked the osteogenesis effect and rescued the ratio of RANKL/OPG in PDLSCs under force treatment for 1 h.ConclusionsOur findings reveal that PDLSCs participate in OTM and that the Wnt/β-catenin pathway maintains bone homeostasis during tooth movement by regulating the balance between osteoblastic and osteoclastic activity.General significanceWe describe a novel potential mechanism related to tooth movement.     

Analysis of a volumetric-modulated arc therapy (VMAT) single phase prostate template as a class solution

AimTo assess a class solution template for volumetric-modulated arc therapy (VMAT) for prostate cancer using plan analysis software.BackgroundVMAT is a development of intensity-modulated radiotherapy (IMRT) with potential advantages for the delivery of radiotherapy (RT) in prostate cancer. Class solutions are increasingly used for facilitating RT planning. Plan analysis software provides an objective tool for evaluating class solutions.Materials and methodsThe class solution for VMAT was based on the current static field IMRT template. The plans of 77 prostate cancer patients were evaluated using a set of in-house plan quality metrics (scores) (PlanIQ™, Sun Nuclear Corporation). The metrics compared the class solution for VMAT planning with the IMRT template and the delivered clinical plan (CP). Eight metrics were associated with target coverage and ten with organs-at-risk (OAR). Individual metrics were summed and the combined scores were subjected to non-parametric analysis. The low-dose wash for both static IMRT and VMAT plans were evaluated using 40 Gy and 25 Gy isodose volumes.ResultsVMAT plans were of equal or better quality than the IMRT template and CP for target coverage (combined score) and OAR combined score. The 40 Gy isodose volume was marginally higher with VMAT than IMRT (4.9%) but lower than CP (−6.6%)(P = 0.0074). The 25 Gy volume was significantly lower with VMAT than both IMRT (−32.7%) and CP (−34.4%)(P < 0.00001).ConclusionsAutomated VMAT planning for prostate cancer is feasible and the plans are equal to or better than the current IMRT class solution and the delivered clinical plan.     

Chemical composition and free radical-scavenging,anticancer and anti-inflammatory activities of the essential oil from Ocimum kilimandscharicum

ObjectiveThe essential oil from the leaves of Ocimum kilimandscharicum (EOOK), collected in Dourados-MS, was investigated for anticancer, anti-inflammatory and antioxidant activity and chemical composition.Materials and methodsThe essential oil was extracted by hydrodistillation, and the chemical composition was performed by gas chromatography–mass spectrometry. The essential oil was evaluated for free radical-scavenging activity using the DPPH assay and was tested in an anticancer assay against ten human cancer cell lines. The response parameter (GI₅₀) was calculated for the cell lines tested. The anti-inflammatory activity was evaluated using carrageenan-induced pleurisy in mice.ResultsThe chemical composition showed 45 components with a predominance of monoterpenes, such as camphor (51.81%), 1,8 cineole (20.13%) and limonene (11.23%). The EOOK exhibited potent free radical-scavenging activity by the DPPH assay with a GI₅₀ of 8.31 μg/ml. The major constituents, pure camphor (IC₅₀ = 12.56 μg/ml) and mixture of the limonene: 1, 8 cineole (IC₅₀ = 23.25 μg/ml) displayed a potent activity. The oral administration of EOOK (at 30 and 100 mg kg⁻¹), as well as the pure camphor or a mixture of 1,8 cineole with limonene, significantly inhibited the carrageenan (Cg) induced pleurisy, reducing the migration of total leukocytes in mice by 82 ± 4% (30 mg kg⁻¹ of EOOK), 95 ± 4% (100 mg kg⁻¹ of EOOK), 83 ± 9% (camphor) and 80 ± 5% (mixture of 1,8 cineole:limonene 1:1). In vitro cytotoxicity screening against a human ovarian cancer cell line displayed high selectivity and potent anticancer activity with GI₅₀ = 31.90 mg ml⁻¹. This work describes the anti-inflammatory, anticancer and antioxidant effects of EOOK for the first time.ConclusionsThe essential oil exhibited marked anti-inflammatory, antioxidant and anticancer effects, an effect that can be attributed the presence of majorital compounds, and the response profiles from chemical composition differed from other oils collected in different locales.     

Glucagon receptor is required for long-term survival: A natural history study of the Mahvash disease in a murine model

Background and aimWe have described a novel Mahvash disease of hyperglucagonemia and pancreatic neuroendocrine tumors (PNETs) associated with an inactivating glucagon receptor mutation, and identified the glucagon receptor-deficient (Gcgr^?/?) mice as its murine model. We aim to elucidate the natural history of the rare Mahvash disease by long-term observation of the Gcgr^?/? mice.Materials and methodWild type (WT) (n = 52), heterozygous (n = 127), and Gcgr^?/? (n = 56) mice living under standard vivarium conditions were observed without specific treatments over 22 months. Autopsy was performed on dead animals.ResultsThe WT and heterozygous mice did not exhibit any measurable differences. The Gcgr^?/? mice became progressively lethargic and cachexic after 12 months. Random glucose levels were stable in WT and heterozygous mice but decreased with age in the Gcgr^?/? mice. At the end of observation, 28/56 Gcgr^?/?, 7/52 WT, and 24/127 heterozygous mice died. The survival curve of Gcgr^?/? mice began to separate from those of WT and heterozygous mice at 12 months and the survival difference widened with age. At 18 months, survival probability was 17% for Gcgr^?/? mice but 77% for WT and 81% for heterozygous mice. Autopsy revealed numerous PNETs up to 15 mm in diameter in most well-preserved Gcgr^?/? pancreata (17/20) but none in WT or heterozygous ones. Four Gcgr^?/? mice developed liver or subcutaneous metastasis.ConclusionThe untreated Mahvash disease may cause cachexia, severe hypoglycemia, and early death. Patients with Mahvash disease need to undergo life-long surveillance for PNETs. Functional glucagon receptor is thus required for long-term survival.     

Radiosensitization of Pancreatic Cancer Cells In Vitro and In Vivo through Poly (ADP-ribose) Polymerase Inhibition with ABT-888

OBJECTIVESTo determine whether poly (ADP-ribose) polymerase-1/2 (PARP-1/2) inhibition enhances radiation-induced cytotoxicity of pancreatic adenocarcinoma in vitro and in vivo, and the mechanism by which this occurs.MethodsPancreatic carcinoma cells were treated with ABT-888, radiation, or both. In vitro cell viability, apoptosis, and PARP activity were measured. Orthotopic xenografts were generated in athymic mice and treated with ABT-888 (25 mg/kg), radiation (5 Gy), both, or no treatment. Mice were monitored with bioluminescence imaging.RESULTSIn vitro, treatment with ABT-888 and radiation led to higher rates of cell death after 8 days (P < .01). Co-treatment with 5 Gy and 1, 10 or 100 μmol/l of ABT-888 led to dose enhancement factors of 1.29, 1.41 and 2.36, respectively. Caspase activity was not significantly increased when treated with ABT-888 (10 μmol/l) alone (1.28-fold, P = .08), but became significant when radiation was added (2.03-fold, P < .01). PARP activity increased post-radiation and was abrogated following co-treatment with ABT-888. In vivo, treatment with ABT-888, radiation or both led to tumor growth inhibition (TGI) of 8, 30 and 39 days, and survival at 60 days of 0%, 0% and 40%, respectively.CONCLUSIONSABT-888 with radiation significantly enhanced tumor response in vitro and in vivo. ABT-888 inhibited PAR protein polymerization resulting in dose-dependent feedback up-regulation of PARP and p-ATM suggesting increased DNA damage. This translated into enhancement in TGI and survival with radiation in vivo. In vitro PAR levels correlated with levels of tumor apoptosis suggesting potential as a predictive biomarker. These data are being used to support a Phase I study in locally advanced pancreatic cancer.     

Stabilization of d-amino acid oxidase from Rhodosporidium toruloides by encapsulation in polyallylamine-mediated biomimetic silica

d-Amino acid oxidase from Rhodosporidium toruloides (RtDAO) and Fe₃O₄ magnetic nanoparticles were encapsulated simultaneously within biomimetic silica, as mediated by polyallylamine. The capacity for this enzyme reached 193 mg/g of biomimetic silica when 15 mg/ml RtDAO was used during encapsulation; the average encapsulation efficiency was approximately 74%. The T_m value (the temperature at which 50% of the initial activity was retained after 1 h of incubation) was increased from 44.3 °C of the free RtDAO to 57.7 °C, clearly indicating the thermal stability was improved by encapsulation. In the presence of 50 mM hydrogen peroxide, encapsulated RtDAO had a half-life of 148 min, an approximately 2-fold increase in resistance to hydrogen peroxide as compared to 78-min half-life of the free form. The encapsulation process is simple and can be completed within minutes; besides, the resultant enzymes can be recovered easily under magnetic field. Such preparation of encapsulated d-amino acid oxidase could be exploited for many potential applications.     

Antinociceptive action of NOP and opioid receptor agonists in the mouse orofacial formalin test

Nociceptin/orphanin FQ (N/OFQ) modulates several biological functions, including pain transmission via selective activation of a specific receptor named NOP. The aim of this study was the investigation of the antinociceptive properties of NOP agonists and their interaction with opioids in the trigeminal territory. The orofacial formalin (OFF) test in mice was used to investigate the antinociceptive potential associated to the activation of NOP and opioid receptors. Mice subjected to OFF test displayed the typical biphasic nociceptive response and sensitivity to opioid and NSAID drugs. Mice knockout for the NOP gene displayed a robust pronociceptive phenotype. The NOP selective agonist Ro 65-6570 (0.1–1 mg kg⁻¹) and morphine (0.1–10 mg kg⁻¹) elicited dose dependent antinociceptive effects in the OFF with the alkaloid showing larger effects; the isobologram analysis of their actions demonstrated an additive type of interaction. The mixed NOP/opioid receptor agonist cebranopadol elicited potent (0.01–0.1 mg kg⁻¹) and robust antinociceptive effects. In the investigated dose range, all drugs did not modify the motor performance of the mice in the rotarod test. Collectively the results of this study demonstrated that selective NOP agonists and particularly mixed NOP/opioid agonists are worthy of development as innovative drugs to treat painful conditions of the trigeminal territory.     

Limited versus total epithelial debridement ocular surface injury: Live fluorescence imaging of hemangiogenesis and lymphangiogenesis in Prox1-GFP/Flk1::Myr-mCherry mice

BackgroundImmunohistochemical staining experiments have shown that both hemangiogenesis and lymphangiogenesis occur following severe corneal and conjunctival injury and that the neovascularization of the cornea often has severe visual consequences. To better understand how hemangiogenesis and lymphangiogenesis are induced by different degrees of ocular injury, we investigated patterns of injury-induced corneal neovascularization in live Prox1-GFP/Flk1::myr-mCherry mice, in which blood and lymphatic vessels can be imaged simultaneously in vivo.MethodsThe eyes of Prox1-GFP/Flk1::myr-mCherry mice were injured according to four models based on epithelial debridement of the: A) central cornea (a 1.5-mm-diameter circle of tissue over the corneal apex), B) total cornea, C) bulbar conjunctiva, and D) cornea + bulbar conjunctiva. Corneal blood and lymphatic vessels were imaged on days 0, 3, 7, and 10 post-injury, and the percentages of the cornea containing blood and lymphatic vessels were calculated.ResultsNeither central corneal nor bulbar conjunctival debridement resulted in significant vessel growth in the mouse cornea, whereas total corneal and corneal + bulbar conjunctival debridement did. On day 10 in the central cornea, total cornea, bulbar conjunctiva, and corneal + bulbar conjunctival epithelial debridement models, the percentage of the corneal surface that was occupied by blood vessels (hemangiogenesis) was 1.9 ± 0.8%, 7.14 ± 2.4%, 2.29 ± 1%, and 15.05 ± 2.14%, respectively, and the percentage of the corneal surface that was occupied by lymphatic vessels (lymphangiogenesis) was 2.45 ± 1.51%, 4.85 ± 0.95%, 2.95 ± 1.27%, and 4.15 ± 3.85%, respectively.ConclusionsSubstantial corneal debridement was required to induce corneal neovascularization in the mouse cornea, and the corneal epithelium may therefore be partially responsible for maintaining corneal avascularity.General significanceOur study demonstrates that GFP/Flk1::myr-mCherry mice are a useful model for studying coordinated hemangiogenic and lymphangiogenic responses.     

Antimicrobial activity of the toxin VdTX-I from the spider Vitalius dubius (Araneae,Theraphosidae)

BackgroundCurrently there is an urgent need to develop new classes of antimicrobial agents with different mechanisms of action from conventionally antibiotics used for the control of pathogenic microorganisms. The acylpolyamine called VdTX-I was isolated from the venom of the tarantula Vitalius dubius, and first described with activity as an antagonist of nicotinic cholinergic receptors. The main objective of this study was to investigate the antimicrobial activity found in the venom of the spider, with emphasis on the toxin VdTX-I.MethodsAntimicrobial assays were performed in 96 well plates culture against 14 micro-organisms (fungi, yeasts and bacteria), which were tested concentrations from 0.19 to 100 μM of VdTX-I. After qualitative analysis, dose-response curve assays were performed in bacterial kill curve using MTT reagent and hemolytic assay.ResultsThe antimicrobial activity of the VdTX-I toxin was observed in 12 tested species of Candida, Trichosporiun, Staphylococcus and Micrococcus. The toxicity had a dose-response at 3.12 µM – 100 μM in Candida albicans, Candida guillermondii, Micrococcus luteus and Escherichia coli. VdTX-I took about 5 min to inhibit bacterial growth, which was faster than streptomycin. The toxin showed no hemolytic activity between 0.19 and 100 μM. At 2.5 µg/mL of toxin it was observed no growth inhibition against a mammalian cell lineage.ConclusionsThe VdTX-I toxin has a significant antimicrobial activity, with broad spectrum, and is experimentally inert to mammalian blood cells.General SignificanceThis paper explores the antimicrobial potential of the spider toxin VdTX-I, which can provide a new model to design new antimicrobial drugs.     

Hysteresis losses and specific absorption rate measurements in magnetic nanoparticles for hyperthermia applications

BackgroundMagnetic hysteresis loops areas and hyperthermia on magnetic nanoparticles have been studied with the aim of providing reliable and reproducible methods of measuring the specific absorption rate (SAR).MethodsThe SAR of Fe₃O₄ nanoparticles with two different mean sizes, and Ni_1 −xZn_xFe₂O₄ ferrites with 0 ≤ x ≤ 0.8 has been measured with three approaches: static hysteresis loops areas, dynamic hysteresis loops areas and hyperthermia of a water solution. For dynamic loops and thermometric measurements, specific experimental setups have been developed, that operate at comparable frequencies (≈ 69 kHz and ≈ 100 kHz respectively) and rf magnetic field peak values (up to 100 mT). The hyperthermia setup has been fully modelled to provide a direct measurement of the SAR of the magnetic nanoparticles by taking into account the heat exchange with the surrounding environment in non-adiabatic conditions and the parasitic heating of the water due to ionic currents.ResultsDynamic hysteresis loops are shown to provide an accurate determination of the SAR except for superparamagnetic samples, where the boundary with a blocked regime could be crossed in dynamic conditions. Static hysteresis loops consistently underestimate the specific absorption rate but can be used to select the most promising samples.ConclusionsA means of reliably measure SAR of magnetic nanoparticles by different approaches for hyperthermia applications is presented and its validity discussed by comparing different methods.General significanceThis work fits within the general subject of metrological traceability in medicine with a specific focus on magnetic hyperthermia. This article is part of a Special Issue entitled "Recent Advances in Bionanomaterials" Guest Editor: Dr. Marie-Louise Saboungi and Dr. Samuel D. Bader.     

Hydrolytic enzymes production by Aspergillus section Nigri in presence of butylated hydroxyanisole and propyl paraben on peanut meal extract agar

BackgroundIn the last years, food grade antioxidants are used safely as an alternative to traditional fungicides to control fungal growth in several food and agricultural products.AimsIn this work, the effect of butylated hydroxyanisole (BHA) and propyl paraben (PP) on two hydrolytic enzyme activity (β-d-glucosidase and α-d-galactosidase) by Aspergillus section Nigri species under different water activity conditions (a_W; 0.98, 0.95 and 0.93) and incubation time intervals (24, 48, 72 and 96 h) was evaluated on peanut-based medium.MethodsThe activity of two glycosidases, β-d-glucosidase and α-d-galactosidase, was assayed using as substrates 4-nitrophenyl-β-d-glucopyranosido and 4-nitrophenyl-α-d-galactopyranosido, respectively. The enzyme activity was determined by the increase in optical density at 405 nm caused by the liberation of p-nitrophenol by enzymatic hydrolysis of the substrate. Enzyme activity was expressed as micromoles of p-nitrophenol released per minute.ResultsThe major inhibition in β-d-glucosidase activity of A. carbonarius and A. niger was found with 20 mmol l⁻¹ of BHA or PP at 0.98 and 0.95 a_W, respectively, whereas for α-d-galactosidase activity a significant decrease in enzyme activity with respect to control was observed in A. carbonarius among 5 to 20 mmol l⁻¹ of BHA or PP in all conditions assayed. Regarding A. niger, the highest percentages of enzyme inhibition activity were found with 20 mmol l⁻¹ of BHA or PP at 0.95 a_W and 96 h.ConclusionsThe results of this work provide information about the capacity of BHA and PP to inhibit in vitro conditions two of the most important hydrolytic enzymes produced by A. carbonarius and A. niger species.     

Antileishmanial activity of essential oil from Chenopodium ambrosioides and its main components against experimental cutaneous leishmaniasis in BALB/c mice

Chenopodium ambrosioides have been used during centuries by native people to treat parasitic diseases.Aims of the studyTo compare the in vivo anti-leishmanial activity of the essential oil (EO) from C. ambrosioides and its major components (ascaridole, carvacrol and caryophyllene oxide).Materials and methodsAnti-leishmanial effect was evaluated in BALB/c mice infected with Leishmania amazonensis and treated with the EO, main compounds and artificial mix of pure components by intralesional route at 30 mg/kg every 4 days during 14 days. Diseases progression and parasite burden in infected tissues were determined.ResultsEO prevented lesion development compared (p < 0.05) with untreated animals and treated with vehicle. In addition, the efficacy of EO was also statistically superior (p < 0.05) compared with the glucantime-treated animals. No potential effects were observed with pure components treatment. Mix of pure compounds cause death of animals after 3 days of treatment.ConclusionsOur results demonstrate the superiority of EO against experimental cutaneous leishmaniasis caused by L. amazonensis.