Resolving stepping rotation in Thermus thermophilus H+-ATPase/synthase with an essentially drag-free probe

Vacuole-type ATPases (VoV1) and FoF1 ATP synthases couple ATP hydrolysis/synthesis in the soluble V1 or F1 portion with proton (or Na+) flow in the membrane-embedded Vo or Fo portion through rotation of one common shaft. Here we show at submillisecond resolutions the ATP-driven rotation of isolated V1 and the whole VoV1 from Thermus thermophilus, by attaching a 40-nm gold bead for which viscous drag is almost negligible. V1 made 120° steps, commensurate with the presence of three catalytic sites. Dwells between the steps involved at least two events other than ATP binding, one likely to be ATP hydrolysis. VoV1 exhibited 12 dwell positions per revolution, consistent with the 12-fold symmetry of the Vo rotor in T. thermophilus. Unlike F1 that undergoes 80°–40° substepping, chemo-mechanical checkpoints in isolated V1 are all at the ATP-waiting position, and Vo adds further bumps through stator–rotor interactions outside and remote from V1

Intravenous dosing of tocilizumab in patients younger than two years of age with systemic juvenile idiopathic arthritis

The anti-interleukin-6 receptor-alpha antibody tocilizumab was approved for intravenous (IV) injection in the treatment of patients with systemic juvenile idiopathic arthritis (sJIA) aged 2 to 17 years based on results of a randomized controlled phase 3 trial. Tocilizumab treatment in systemic juvenile idiopathic arthritis (sJIA) patients younger than 2 was investigated in this open-label phase 1 trial and compared with data from the previous trial in patients aged 2 to 17 years.Patients younger than 2 received open-label tocilizumab 12 mg/kg IV every 2 weeks (Q2W) during a 12-week main evaluation period and an optional extension period. The primary end point was comparability of pharmacokinetics during the main evaluation period to that of the previous trial (in patients aged 2-17 years), and the secondary end point was safety; pharmacodynamics and efficacy end points were exploratory. Descriptive comparisons for pharmacokinetics, pharmacodynamics, safety, and efficacy were made with sJIA patients aged 2 to 17 years weighing < 30 kg (n = 38) who received tocilizumab 12 mg/kg IV Q2W in the previous trial (control group).Eleven patients (mean age, 1.3 years) received tocilizumab during the main evaluation period. The primary end point was met: tocilizumab exposures for patients younger than 2 were within the range of the control group (mean [±SD] μg/mL concentration at the end-of-dosing interval [Cmin]: 39.8 [±14.3] vs 57.5 [±23.3]; maximum concentration [Cmax] postdose: 288 [±40.4] vs 245 [±57.2]). At week 12, pharmacodynamic measures were similar between patients younger than 2 and the control group; mean change from baseline in Juvenile Arthritis Disease Activity Score-71 was - 17.4 in patients younger than 2 and - 28.8 in the control group; rash was reported by 14.3 and 13.5% of patients, respectively. Safety was comparable except for the incidence of serious hypersensitivity reactions (27.3% in patients younger than 2 vs 2.6% in the control group).Tocilizumab 12 mg/kg IV Q2W provided pharmacokinetics, pharmacodynamics, and efficacy in sJIA patients younger than 2 comparable to those in patients aged 2 to 17 years. Safety was comparable except for a higher incidence of serious hypersensitivity events in patients younger than 2 years.Juvenile idiopathic arthritis.ClinicalTrials.gov, NCT01455701 . Registered, October 20, 2011, Date of enrollment of first participant: October 26, 2012

Akutna oralna toksičnost organofosfornih insekticida i inhibicija kolinesteraza u pilića

Acute toxic effects of three commonly used insecticidal preparations of the organophosphates chlorpyrifos, diazinon, and dichlorvos were examined in mixed breed broiler chicks, and cholinesterase activity in plasma and brain were measured. The acute (24 h) oral median lethal doses (LD50) of chlorpyrifos, diazinon, and dichlorvos were 10.79 mg kg-1, 6.32 mg kg-1, and 6.30 mg kg-1, respectively, as determined by the up-and-down method in chicks. Signs of cholinergic toxicosis in the chicks appeared within two hours after dosing, and they included salivation, lacrimation, gasping, frequent defecation, drooping of wings, tremors, convulsions, and recumbency before death. Halving the oral LD50 of chlorpyrifos (5 mg kg-1), diazinon (3 mg kg-1), and dichlorvos (3 mg kg-1) caused immobility and wing drooping, but not the clinical signs of cholinergic toxicity. However, at full LD50 doses of these insecticides, chicks showed clinical signs of cholinergic toxicity similar to those seen in the LD50 experiments. Two out of six chicks died within two hours after treatment with LD50 doses of chlorpyrifos and dichlorvos, whereas LD50 dosing with diazinon caused death in three out of six chicks. Compared to control values, the insecticides reduced plasma and whole brain cholinesterase activities by 29 % to 84 % and 18 % to 77 %, respectively, depending on the dose. The decrease in plasma cholinesterase correlated well (r = 0.82) with that of the brain. These data suggest that organophosphate insecticides administered orally at LD50 doses induce clinical signs of cholinergic poisoning and concurrently reduce brain and plasma cholinesterase activities in chicks.Ispitano je akutno toksično djelovanje triju često rabljenih organofosfornih insekticida klorpirifosa, diazinona i diklorvosa u brojlera te je izmjerena aktivnost kolinesteraza u njihovoj plazmi i mozgu. Srednja letalna doza LD50 klorpirifosa iznosila je 10,79 mg kg-1, diazinona 6,32 mg kg-1 te diklorvosa 6,30 mg kg-1. Prvi su se znakovi kolinergičkoga sindroma u pilića javili unutar dva sata od oralne primjene, a obuhvaćali su slinjenje, suženje, teško disanje, učestalu defekaciju, obješena krila, drhtavicu, grčenje i nesposobnost stajanja uoči smrti. Oralna primjena polovice srednje letalne doze insekticida klorpirifosa (5 mg kg-1), diazinona (3 mg kg-1) i diklorvosa (3 mg kg-1) dovela je do nepokretnosti i obješenih krila, ali bez kliničkih znakova kolinergičke toksičnosti koji su uočeni kod pokusa radi utvrđivanja srednje letalne doze (LD50). Međutim, doze ovih insekticida koje su odgovarale LD50, dovele su do kliničkih znakova kolinergičke toksičnosti sličnih onima zamijećenim kod utvrđivanja LD50. Dva od šest pilića uginula su unutar dva sata od primjene bilo klorpirifosa bilo diklorvosa u dozama koje su odgovarale LD50, dok je diazinon u odgovarajućoj srednjoj letalnoj dozi uzrokovao smrt triju od šest pilića. U odnosu na kontrolne vrijednosti, insekticidi su doveli do smanjenja aktivnosti kolinesteraze koja je ovisila o dozi, a kretala se od 29 % do 84 % u plazmi te od 18 % do 77 % u mozgu. Pad aktivnosti kolinesteraze u plazmi dobro je korelirao s njezinim padom u mozgu (r=0,82). Ovi podaci upućuju na to da oralna primjena organofosfornih insekticida u dozama koje odgovaraju srednjoj letalnoj dozi dovode do znakova kolinergičkoga trovanja u pilića te do istodobnoga pada aktivnosti kolinesteraza u mozgu i plazmi

Knockdown of the Drosophila Fused in Sarcoma (FUS) Homologue Causes Deficient Locomotive Behavior and Shortening of Motoneuron Terminal Branches

Mutations in the fused in sarcoma/translated in liposarcoma gene (FUS/TLS, FUS) have been identified in sporadic and familial forms of amyotrophic lateral sclerosis (ALS). FUS is an RNA-binding protein that is normally localized in the nucleus, but is mislocalized to the cytoplasm in ALS, and comprises cytoplasmic inclusions in ALS-affected areas. However, it is still unknown whether the neurodegeneration that occurs in ALS is caused by the loss of FUS nuclear function, or by the gain of toxic function due to cytoplasmic FUS aggregation. Cabeza (Caz) is a Drosophila orthologue of human FUS. Here, we generated Drosophila models with Caz knockdown, and investigated their phenotypes. In wild-type Drosophila, Caz was strongly expressed in the central nervous system of larvae and adults. Caz did not colocalize with a presynaptic marker, suggesting that Caz physiologically functions in neuronal cell bodies and/or their axons. Fly models with neuron-specific Caz knockdown exhibited reduced climbing ability in adulthood and anatomical defects in presynaptic terminals of motoneurons in third instar larvae. Our results demonstrated that decreased expression of Drosophila Caz is sufficient to cause degeneration of motoneurons and locomotive disability in the absence of abnormal cytoplasmic Caz aggregates, suggesting that the pathogenic mechanism underlying FUS-related ALS should be ascribed more to the loss of physiological FUS functions in the nucleus than to the toxicity of cytoplasmic FUS aggregates. Since the Caz-knockdown Drosophila model we presented recapitulates key features of human ALS, it would be a suitable animal model for the screening of genes and chemicals that might modify the pathogenic processes that lead to the degeneration of motoneurons in ALS

Noninvasive estimation of tumour viability in a xenograft model of human neuroblastoma with proton magnetic resonance spectroscopy (1H MRS)

The aim of the study was to evaluate proton magnetic resonance spectroscopy (1H MRS) for noninvasive biological characterisation of neuroblastoma xenografts in vivo. For designing the experiments, human neuroblastoma xenografts growing subcutaneously in nude rats were analysed in vivo with 1H MRS and magnetic resonance imaging at 4.7 T. The effects of spontaneous tumour growth and antiangiogenesis treatment, respectively, on spectral characteristics were evaluated. The spectroscopic findings were compared to tumour morphology, proliferation and viable tumour tissue fraction. The results showed that signals from choline (Cho)-containing compounds and mobile lipids (MLs) dominated the spectra. The individual ML/Cho ratios for both treated and untreated tumours were positively correlated with tumour volume (P<0.05). There was an inverse correlation between the ML/Cho ratio and the viable tumour fraction (r=−0.86, P<0.001). Higher ML/Cho ratios concomitant with pronounced histological changes were seen in spectra from tumours treated with the antiangiogenic drug TNP-470, compared to untreated control tumours (P<0.05). In conclusion, the ML/Cho ratio obtained in vivo by 1H MRS enabled accurate assessment of the viable tumour fraction in a human neuroblastoma xenograft model. 1H MRS also revealed early metabolic effects of antiangiogenesis treatment. 1H MRS could prove useful as a tool to monitor experimental therapy in preclinical models of neuroblastoma, and possibly also in children

Plasma and whole brain cholinesterase activities in three wild bird species in Mosul, IRAQ: In vitro inhibition by insecticides

Plasma and brain cholinesterase activities were determined in three wild bird species to assess their exposure to organophosphate and carbamate insecticides which are used in agriculture and public health. In the present study, we used an electrometric method for measurement of cholinesterase activities in the plasma and whole brain of three indigenous wild birds commonly found in northern Iraq. The birds used were apparently healthy adults of both sexes (8 birds/species, comprising 3–5 from each sex) of quail (Coturnix coturnix), collard dove (Streptopelia decaocto) and rock dove (Columba livia gaddi), which were captured in Mosul, Iraq. The mean respective cholinesterase activities (Δ pH/30 minutes) in the plasma and whole brain of the birds were as follows: quail (0.96 and 0.29), collard dove (0.97and 0.82) and rock dove (1.44 and 1.42). We examined the potential susceptibility of the plasma or whole brain cholinesterases to inhibition by selected insecticides. The technique of in vitro cholinesterase inhibition for 10 minutes by the organophosphate insecticides dichlorvos, malathion and monocrotophos (0.5 and 1.0 µM) and the carbamate insecticide carbaryl (5 and10 µM) in the enzyme reaction mixtures showed significant inhibition of plasma and whole brain cholinesterase activities to various extents. The data further support and add to the reported cholinesterase activities determined electrometrically in wild birds in northern Iraq. The plasma and whole brain cholinesterases of the birds are highly susceptible to inhibition by organophosphate and carbamate insecticides as determined by the described electrometric method, and the results further suggest the usefulness of the method in biomonitoring wild bird cholinesterases

Effects of 3 chemical treatments on in vitro fermentation of rice straw by mixed rumen microbes in the presence or absence of anaerobic rumen fungi

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