BaCl2 Research Articles

Hydroxychloroquine induces endothelium-dependent and endothelium-independent relaxation of rat aorta.

Hydroxychloroquine (HCQ) is an antimalarial that is widely used in the management of rheumatoid arthritis and other autoimmune diseases. In this study, we aimed to examine the vascular effects of HCQ on rat aorta (RA). The RA rings were suspended in isolated organ baths and tension was recorded isometrically. HCQ-induced relaxations were tested in the presence of the nitric oxide synthase inhibitor, nitro-L-arginine methyl ester (L-NAME, 100 mM); the cyclooxygenase enzyme inhibitor, indomethacin (10 mM); the calcium (Ca2+) ion channel blocker, nilvadipine (10 μM); and the K+ ion channel inhibitors, tetraethylammonium (1 mM), glibenclamide (10 mM), 4-aminopyridine (1 mM), and barium chloride (30 mM). The effect of HCQ on Ca2+ channels was examined using Ca2+-free Krebs solution, and adding calcium chloride (CaCl2 , 10-5- 10-2 M) cumulatively to baths incubated with HCQ. Removing the endothelium resulted in less relaxation of RA rings compared to endothelium-intact rings (p < 0.05). The effect of endothelium was supported by using L-NAME where HCQ produced-vasorelaxation was decreased (p < 0.05). The contraction of vascular rings was inhibited to a significant degree following the addition of CaCl2 , PE, or KCl on HCQ-incubated RA rings (p < 0.05). The incubation of the RA rings with the Ca2+ channel blocker, the K+ channel blockers, and the COX inhibitor, indomethacin did not significantly affect vascular relaxation induced by HCQ. HCQ produced relaxation of RA rings. The relaxation mechanism differs according to the concentration of HCQ. At con-centrations of 10-6 and 10-5 M, the relaxation is endothelium-dependent and mediated by NO. We strongly suggest that Ca2+ channel inhibition is involved at concentrations of 10-5 and 10-4 M, as well as NO.

Synthesis, Characterization and Antimicrobial Activities of mixed Ligand Metals Complexes with Trimethoprim and Potassium Thiocyanate

A new series of Mn (II) and Ni (II) mixed ligands-metal complexes derived from trimethoprim (TMP) and thiocyanate (TC) have been synthesized in aqueous medium and characterized by spectroscopic studies using IR. The coordination of the two ligands towards central metal ions has been proposed in the light of elemental analysis using barium chloride gravimetric method, various colours of metal complexes were obtained ranging from green to light green and found to be soluble in ethanol, butanol, and insoluble in n-hexane, propan-2-ol, and benzene. The following physical parameters were also observed; solubility, melting point and conductivity. The results of the physical and spectroscopic data confirmed that the ligands are chelating agents. The results of spectroscopic studies revealed that TMP acts as a mono-dentate ligand coordinating through the nitrogen of the pyrimidine group and coordination through the nitrogen of the amine group, while in the TC coordination occurred through the sulphur and nitrogen groups because thiocyanate shares its negative charge approximately equally between sulfur and nitrogen. As a consequence, thiocyanate can act as a nucleophile at either sulfur or nitrogen, it is an ambidentate ligand. Antimicrobial activity of the mixed ligands metal complexes and the free ligands were carried out against the bacterial Escherichia coli, Staphylococcus aureus, Klebsiella pneumonia, Pseudomonas aeruginosa, Bacillius subtilis and the fungi; Sclerotinia trifoliorium, Fusarium oxyporium, Stemania paradoxa, Brotrytis cinerea. The mixed ligands metal complexes showed higher activities when compared to the free ligands of TMP but were less active than the free TC ligand. The complexes of Mn (II) showed the highest antimicrobial activity while the Ni (II) complex showed the least activity against the bacterial and fungi organisms. Structure activity relationship showed that Ni (II) complexes containing sulphate ions are more active, while for Mn (II) complexes containing thiocyanate ions showed more enhanced activity than those containing sulphate ions.

CATALYSTS FOR DESTRUCTION OF HYDROCARBON RAW MATERIALS BASED ON BARIUM CHLORIDE

A barium-containing catalyst is the new effective catalyst for the pyrolysis of hydrocarbons into olefin-containing gas at relatively low temperatures. This article discusses optionsfor the de-velopment of new straight-run gasoline pyrolysis catalysts, platformer raffinates and barium chlo-ride-based thermal cracking gasolines. The strength properties of tableted catalysts with the addi-tion of graphite, FAS (fatty acid synthesis) diethanolamide, phenol-furan resin and clay were stud-ied. When forming the catalysts, the introduction of activity modifying additives is relatively easy. The results of experimental data on a barium chloride catalyst with these modifying additives wereobtained. These data indicate that the production of barium chloride-based catalysts is economi-cally feasible, since it is based on the use of inexpensive and affordable chemical reagents, and this in turn helps to increase the efficiency of using natural non-renewable raw materials and energy saving in the processes of its processing. The catalysts formed with the addition of sodium tetra-chloroaluminate are characterized by catalytic activity in cracking and isomerization processes.Tests were carried out to determine the duration of the catalyst lifetime with various modifications, and the following resultswere obtained: during 700 hof operation at a temperature of 500 °C, the catalyst formed with 3.0% wt. graphite, retains activity on gas formation and the yield of lower olefins. In this case, the coke yield on the skipped feedstock for all catalyst modifications doesnot exceed 2.5% wt. for 30 hof operation at a temperature of 700 °C. It is noteworthy that the catalyst containing NaAlCl4is characterized by a relatively low coke formation.

Self-flux-grown Ba4Fe4ClO9.5-x crystals exhibiting structures with tunable modulation.

The synthesis and X-ray structural study of the new family of compounds Ba4Fe4ClO9.5−x with tunable structural modulation are reported. The framework of the structure has the Ba2Fe4O9.5−x composition, with open hexagonal channels extending along the c-axis. The channels are filled with linear [Ba–Cl–Ba] triplets. The oxygen stoichiometry and the oxidation state of iron both are controlled by the redox conditions during crystal preparation. The modulation of the crystal structure arises from the distribution of the oxygen atoms in the framework and iron coordination polyhedra are a combination of FeO4-tetrahedra, FeO5-bipyramids, and FeO6-octahedra. The structure modulation also originates from the ordered or disordered distribution of the [Ba–Cl–Ba] triplets filling the channels which is also affected by the conditions of the thermal treatment of the crystals. The structure investigation reveals a composition variation from Ba4Fe4ClO9.5 (x = 0), in which Fe exhibits a 3+ oxidation state, to Ba4Fe4ClO8 (x = 1.5) with the framework built exclusively of FeO4 tetrahedra.

Geotrichum Candids Inciting Fruit Rot of Ivy Gourd in Synergistics Effect of Agrochemicals on Carbendazim

There was variation in the MIC of carbendazim among the Geotrichumcandidus incitant of fruit rot of Ivy gourd (Cucurbitaceae) fruits and isolate on (CZA) CzapekDox agar medium plates. Minimum inhibitory concentration (MIC) on CZA plates ranged from 4000 µg/ml while it was more resistant with resistant factor 2. Use of carbendazim with–other agrochemicals like Fungicides (mancozeb, copper oxychloride, chlorothalonil), Insecticides (phorate, chlorpyriphos and endosulfan), Herbicides (metribuzin, sodium salt and atrazine), Antibiotics (bacipen, ambistryn–s and penicillin), Salts (mercuric, chloride, stannous chloride and barium chloride), and Fertilizers (MOP, urea, 10:26:26) inhibited the growth of the pathogen in invitro studies.

Chemical resistance of celsian ceramics in acid and alkaline reagents

In the article, the chemical stability of celsian ceramics at different firing temperatures was investigated and the structural-phase features of the obtained samples before and after interaction with alkaline and acid media were studied.&#x0D; The technology of obtaining test samples was two-stage. The first stage was the synthesis of the celsian phase in a muffle furnace at a temperature of 1200 °C with a holding time of 2 hours and subsequent cooling together with the furnace. The second stage took place in a silitic furnace at temperatures of 1300, 1350 and 1400 °C with a set rate of 15 deg/min and holding at a maximum temperature of 4 hours. The chemical resistance of celsian ceramics was determined in relation to 20 % solutions of HCl and NaOH. The phase composition of the test samples was determined using the method of X-ray phase analysis (X-ray diffraction) using a DRON-3M diffractometer. The studies of the experimental samples microstructure and the surface morphology of their faults were carried out by the direct method of scanning electron microscopy using a scanning electron microscope PhenomPro.&#x0D; It was found that in relation to the 20 % solution of NaOH celsian ceramics was insoluble and has a value of alkali resistance in the range of 99.47—99.67 %. The study of microstructure and phase composition of celsian ceramics samples after treatment with 20 % NaOH solution showed that in all studied samples there was only a crystalline phase of celsian, the corrosion process didn’t occur. In relation to the 20 % HCl solution, the process of celsian ceramics corrosion was observed with the complete chemical interaction of the celsian phase with hydrochloric acid and the subsequent formation of the barium chloride dihydrate phase.

Evaluation of Different Extractants for Boron Estimation in Soils of Odisha and Andhra Pradesh

The present study was conducted to compare the four different extractants widely used in boron (B) determination in soils and to screen the most suitable extractant for acidic (Alfisols) and alkaline (Vertisols) soils of Odisha and Andhra Pradesh. A total of 200 surface soil samples were collected across two sites (100 from each site) representing different pH ranges. Hot-water-soluble boron (HWS-B) extraction procedure being the most widely used B determination procedure was kept as a benchmark in order to compare the B extracting efficiency by the extractants viz., 0.01 M Calcium Chloride (CaCl2), 1 N Ammonium acetate (NH4OAc) pH-7.0 and 0.01 M Barium Chloride. The mean values of hot water extractable B for acidic soils were 0.49 (mean between 0.18 and 1.50 mg kg-1), CaCl2 – 0.42 (mean between 0.14 and 1.52 mg kg-1), BaCl2 – 0.45 (mean between 0.10 and 1.68 mg kg-1) and NH4OAc – 0.60 (mean between 0.17 and 2.43 mg kg-1). The mean values of hot water extractable B for alkaline soils were 1.87 (mean between 0.71 and 4.79 mg kg-1), CaCl2 – 1.57 (mean between 0.45 and 5.43 mg kg-1), BaCl2 – 1.37 (mean between 0.52 and 4.15 mg kg-1) and NH4OAc – 1.92 (mean between 0.85 and 8.33 mg kg-1) in acidic and alkaline soils respectively. The coefficient of variation for extractable B varied from 53.0 to 66.6 and 42.7 to 55.7 in acidic and alkaline soils respectively. The variation in B extracting efficiency in both the types of soils was found in the order: Hot water &gt; Hot CaCl2 &gt; BaCl2 &gt; NH4OAc. Authors conclude that amongst all the compared extractants, 0.01 M CaCl2 extraction may be an adequate procedure for B determination in both the acidic as well as alkaline soils.

Pharmacodynamic Mechanism of Kuanxiong Aerosol for Vasodilation and Improvement of Myocardial Ischemia.

To explore the effect of Kuanxiong Aerosol (KXA) on isoproterenol (ISO)-induced myocardial injury in rat models. Totally 24 rats were radomly divided into control, ISO, KXA low-dose and high-dose groups according to the randomized block design method, and were administered by intragastric administration for 10 consecutive days, and on the 9th and 10th days, rats were injected with ISO for 2 consecutive days to construct an acute myocardial ischemia model to evaluate the improvement of myocardial ischemia by KXA. In addition, the diastolic effect of KXA on rat thoracic aorta and its regulation of ion channels were tested by in vitro vascular tension test. The influence of KXA on the expression of calcium-CaM-dependent protein kinase II (CaMK II)/extracellular regulated protein kinases (ERK) signaling pathway has also been tested. KXA significantly reduced the ISO-induced increase in ST-segment, interventricular septal thickness, cardiac mass index and cardiac tissue pathological changes in rats. Moreover, the relaxation of isolated thoracic arterial rings that had been precontracted using norepinephrine (NE) or potassium chloride (KCl) was increased after KXA treatment in an endothelium-independent manner, and was attenuated by preincubation with verapamil, but not with tetraethylammonium chloride, 4-aminopyridine, glibenclamide, or barium chloride. KXA pretreatment attenuated vasoconstriction induced by CaCl2 in Ca2+-free solutions containing K+ or NE. In addition, KXA pretreatment inhibited accumulation of Ca2+ in A7r5 cells mediated by KCl and NE and significantly decreased p-CaMK II and p-ERK levels. KXA may inhibit influx and release of calcium and activate the CaMK II/ERK signaling pathway to produce vasodilatory effects, thereby improving myocardial injury.

Tuning Alginate Microparticle Size via Atomization of Non-Newtonian Fluids.

A new approach based on the atomization of non-Newtonian fluids has been proposed to produce microparticles for a potential inhalation route. In particular, different solutions of alginate were atomized on baths of different crosslinkers, piperazine and barium chloride, obtaining microparticles around 5 and 40 microns, respectively. These results were explained as a consequence of the different viscoelastic properties, since oscillatory analysis indicated that the formed hydrogel beads with barium chloride had a higher storage modulus (1000 Pa) than the piperazine ones (20 Pa). Pressure ratio (polymer solution-air) was identified as a key factor, and it should be from 0.85 to 1.00 to ensure a successful atomization, obtaining the smallest particle size at intermediate pressures. Finally, a numerical study based on dimensionless numbers was performed to predict particle size depending on the conditions. These results highlight that it is possible to control the microparticles size by modifying either the viscoelasticity of the hydrogel or the experimental conditions of atomization. Some experimental conditions (using piperazine) reduce the particle size up to 5 microns and therefore allow their use by aerosol inhalation.

Study results of the choice of barium salts reagents for wastewater treatment from sulfates

The research on the removal of sulfates from mine wastewater is presented in the article. A new purification method has been proposed that allows removing a significant part of sulfates by precipitation in the form of barium sulfate. The present studies were devoted to the removal of sulfates from mine wastewater with a sulfate content of 1050 mg/l by introducing various doses of barium-containing reagents, namely barium chloride, hydroxide and barium carbonate. Among the listed reagents, the best results were obtained, using barium chloride and hydroxide. The use of barium chloride with a dose of 2700 mg/l and barium hydroxide with a dose of 3200 mg/l made it possible to reduce the concentration of sulfates below the maximum permissible (100 mg/l) when discharged into a reservoir for fishery purposes. A reliable in operation technological scheme for removing sulfates from highly concentrated mine wastewater has been developed, which makes it possible to reduce sulfates in the treated waste liquid discharged into the reservoir to 100 mg/l and below. In this case, the purification is carried out with separation of streams - in a smaller part (about 26% of the incoming); barium chloride is introduced, in the second - barium hydroxide. After that, the streams are mixed again, settled, sent to the calciner and to the post-treatment facilities and discharged into the reservoir. The resulting sludge is stored in special landfills or is processed to extract valuable components.

Efficacy on rabbits with arrhythmia: needling acupoint of Neiguan (PC6) at shallow or deep depth, and retaining needles for 10, 20, or 30 min.

To compare the effects of Neiguan (PC6) acupuncture at different depths and retention time on arrhythmia duration, myocardial tissue morphology, mRNA expression level of L-type calcium channel α1C subunit and Ca2 + -Mg2 + -AtPase activity in tachirrhythmia model of rabbits. The tachyarrhythmia model was made by intravenous injection of barium chloride into the ears of rabbits. A total of 56 healthy adult male New Zealand big-eared white rabbits, apply the random number table method, divided into normal control group (group A), model group (group B), shallow needling Neiguan (PC6) 10 min group (group C), shallow needling Neiguan (PC6) 20 min group (group D), shallow needling Neiguan (PC6) 30 min group (group E), deep needling Neiguan (PC6) 10 min group (group F), deep needling Neiguan (PC6) 20 min group (group G), deep needling Neiguan (PC6) 30 min group (group H), 7 animals in each group. Electrocardiograms were used to collect the duration of arrhythmia; hematoxylin-eosin staining method was performed on myocardial tissue, RT-PCR tested the expression of α1C subunit mRNA, and the activity of Ca2 + -Mg2 + -ATPase were quantified by phosphorus determination method. The duration of arrhythmia in each acupuncture treatment group was shortened to varying degrees. Compare to the model group, the tissue damage from barium chloride inducing was improved in the acupuncture group. Compared to the model group, except for group E, most treatment groups had varying degrees of improvement with significantly down-regulated L-type calcium channel α1C subunit mRNA expressions level and increased Ca2+ -Mg2+ -ATPase activity. The effect of acupuncture at Neiguan (PC6) with different depths and retention time can reduce the duration of arrhythmia induced by barium chloride relatively, improve the induced pathological changes, down regulate L-type calcium channel α1C subunit mRNA expressions level and increase Ca2 + -Mg2 + -ATPase activity. Both the shallow and deep tissues of Neiguan (PC6) may be involved in transmitting acupuncture information. There is an optimal induction period for shallow needling at Neiguan (PC6) to reach the best therapeutic effect.

Radium removal from mine waters with the application of barium chloride and zeolite: comparison of efficiency

In several coal mines in the Upper Silesian Coal Basin (USCB), in Poland, radium removal from mine water was necessary in order to mitigate the negative results of radium release with mine effluents. The most efficient method of radium removal was based on the application of barium chloride, implemented in full technical scale in two Polish collieries. Removal efficiency exceeding 95% of the initial activity was achieved. The technology was implemented in full technical scale in two collieries. The problem was that barium chloride is dangerous to health and moreover continuous use of the powdered chemical was required to achieve good results. Therefore, the possible application of zeolite for radium removal was tested in laboratory experiments. This passive technique would be less hazardous for miners and would not require full-time supervision meaning it would enable a reduction in workload. The main goal of the investigations described in this paper was to check the capability of zeolites to remove natural radionuclides from mine waters and compare the removal efficiency of radium isotopes with the results obtained from the application of barium chloride solution for the same purpose.

Ethyl Acetate Fraction from Leandra dasytricha (A. Gray) Cong. Leaves Promotes Vasodilatation and Reduces Blood Pressure in Normotensive and Hypertensive Rats.

Leandra dasytricha (A. Gray) Cong. is widely distributed in the south of Brazil and is commonly used for cardiovascular and kidney ailments. For this study, we used male Wistar normotensive rats (NTRs) and spontaneously hypertensive rats (SHRs) to verify the effects of the ethyl acetate fraction (EAF) obtained from L. dasytricha leaves on isolated aorta relaxation and in the arterial blood pressure. The EAF was analyzed by LC-DAD-MS, and several components were annotated, including hydrolysable tannins, triterpenes, and O- and C-glycosylated dihydrochalcones, such as the most intense ion peak relative to C-hexosyl phloretin (nothofagin; compound number 13). The EAF caused a concentration and endothelium-dependent relaxation of the aorta in both NTRs and SHRs. This effect was abolished in the endothelium-denuded aorta. L-NAME, a nonselective nitric oxide synthase inhibitor, and ODQ, a soluble guanylate cyclase inhibitor, entirely blocked the EAF-induced relaxation. The presence of a muscarinic receptor antagonist or a cyclooxygenase inhibitor did not alter the EAF's effectiveness in relaxing the aorta. The preincubation with tetraethylammonium, a Ca2+-activated K+ channel blocker, and with 4-aminopyridine, a voltage-dependent K+ channel blocker, significantly interfered with the EAF's relaxation. However, the incubation with glibenclamide, an ATP-sensitive K+ channel blocker, and barium chloride, an inward-rectifier K+ channel blocker, did not interfere with the EAF-induced relaxation. The EAF treatment also caused a dose-dependent decrease in the mean arterial pressure, systolic arterial pressure, and diastolic arterial pressure of both NTRs and SHRs, without significantly interfering with heart rate values. In conclusion, this study demonstrated the EAF-induced vasorelaxant and hypotensive actions, primarily dependent on the endothelium function and mainly with the participation of the nitric oxide and Ca2+-activated and voltage-dependent K+ channels.

Species dependent cardiac electrophysiological effects elicited by various potassium channel blocking drugs

Rodents are commonly used as models in electrophysiology. However, distinct differences exist between large animals and rodents in terms of their ion channel expression and action potential shapes, possibly limiting the translational value of findings obtained in rodents. We aimed for a direct comparison of the possible impact of selective inhibition of ion channels on the cardiac repolarization in preparations from human hearts and from model species. We applied the standard microelectrode technique at 37°C on cardiac ventricular preparations (papillary muscles and trabecules) from human (n = 63), dog (n = 47), guinea pig (n = 53), rat (n = 43), and rabbit (n = 16) hearts, paced at 1 Hz. To selectively block the IKur current, 1 µM XEN-D101; IK1 current, 10 µM barium chloride; IKr current, 50 nM dofetilide; IKs current, 500 nM HMR-1556; and Ito current, 100 µM chromanol-293B were applied directly to the tissue bath. The block of IKur and IK1 elicited significantly more prominent prolongation of APD in rats (35.6% and 67.9%, respectively) when compared with the other species, including that of human (1.0% and 2.6%, respectively). On the other hand, IKr block did not affect APD in rat preparations (1.6%), whereas it elicited marked prolongation in other species (9.0-47.7%), especially being pronounced in human preparations (60.3%). IKs inhibition elicited similar but minor APD prolongation (0.3-11.4%) in all species. Inhibition of Ito moderately lengthened APD in dog (22.3%) and rabbit (17.5%) preparations but elicited no change of APD in human preparations. In contrast, block of Ito caused marked APD prolongation in rat preparations (33.2%). Our findings suggest that the specific inhibition of various ion channels elicits fundamentally different effects in rodent ventricular action potential when compared with those of other species, including human. Therefore, from a translational standpoint, rodent models in cardiac electrophysiological and arrhythmia research should be used with great caution.

Physiological role of K+ channels in irisin-induced vasodilation in rat thoracic aorta

Irisin, an exercise-induced myokine, has been shown to have a peripheral vasodilator effect. However, little is known about the mechanisms underlying its effects. In this study, it was aimed to investigate the vasoactive effects of irisin on rat thoracic aorta, and the hypothesis that voltage-gated potassium (KV) channels, ATP-sensitive potassium (KATP) channels, small-conductance calcium-activated potassium (SKCa) channels, large-conductance calcium-activated potassium (BKCa) channels, intermediate-conductance calcium-activated potassium (IKCa) channels, inward rectifier potassium (Kir) channels, and two-pore domain potassium (K2P) channels may have roles in these effects. Isometric contraction-relaxation responses of isolated thoracic aorta rings were measured with an organ bath model. The steady contraction was induced with both 10−5 M phenylephrine and 45 mM KCl, and then the concentration-dependent responses of irisin (10-9-10-6 M) were examined. Irisin exerted the vasorelaxant effects in both endothelium-intact and -denuded aortic rings at concentrations of 10-8, 10-7, and 10-6 M (p < 0.001). Besides, KV channel blocker 4-aminopyridine, KATP channel blocker glibenclamide, SKCa channel blocker apamin, BKCa channel blockers tetraethylammonium and iberiotoxin, IKCa channel blocker TRAM-34, and Kir channel blocker barium chloride incubations significantly inhibited the irisin-induced relaxation responses. However, incubation of K2P TASK-1 channel blocker anandamide did not cause a significant decrease in the relaxation responses of irisin. In conclusion, the first physiological findings were obtained regarding the functional relaxing effects of irisin in rat thoracic aorta. Furthermore, this study is the first to report that irisin-induced relaxation responses are associated with the activity of KV, KATP, SKCa, BKCa, IKCa, and Kir channels.

Hierarchical Self-Assembly of Metal-Ion-Modulated Chitosan Tubules.

Soft materials such as gels or biological tissues can develop via self-assembly under chemo-mechanical forces. Here, we report the instantaneous formation of soft tubular structures with a two-level hierarchy by injecting a mixture of inorganic salt and chitosan (CS) solution from below into a reactor filled with alkaline solution. Folding and wrinkling instabilities occur on the originally smooth surface controlled by the salt composition and concentration. Liesegang-like precipitation patterns develop on the outer surface on a μm length scale in the presence of calcium chloride, while the precipitate particles are distributed evenly in the bulk as corroborated by X-ray μ-CT. On the other hand, barium hydroxide precipitates out only in the thin outer layer of the CS tubule when barium chloride is introduced into the CS solution. Independent of the concentration of the weakly interacting salt, an electric potential gradient across the CS membrane develops, which vanishes when the pH difference between the two sides of the membrane diminishes.

Vasodilatory effects of betaine on isolated rat pulmonary artery rings.

The aim of this study was to investigate the vasodilatory effects of betaine, an alkaloid isolated from Lycium barbarum, on isolated pulmonary artery rings in rats and its possible mechanisms. Pulmonary vessels of normal Sprague-Dawley rats were isolated and pre-contracted using norepinephrine. Then, betaine was cumulatively added in differing concentrations (0.02-0.14 mg/mL), and the tension curve was observed and recorded. Changes in the tension of the pulmonary artery rings with an intact endothelium and a dissected endothelium were recorded. The interactions among betaine and NG-nitro-L-arginine methyl ester, indomethacin, 4-aminopyridine, barium chloride, and glibenclamide were evaluated. The experimental results show that betaine can relax the pulmonary artery rings pre-contracted by norepinephrine. Furthermore, pre-incubation with NG-nitro-L-arginine methyl ester and indomethacin did not inhibit betaine vasodilation, demonstrating that vasodilation by betaine is endothelium-dependent. Additionally, pretreatment of pulmonary artery rings with 4-aminopyridine and glibenclamide had no effect on betaine. However, pretreatment of pulmonary artery rings with barium chloride attenuated the effects of betaine. In conclusion, the vasodilatory effects of betaine on pulmonary artery rings is associated with inward rectifier potassium channels.

Stability and Biocompatibility Tests of Alginate as Cochlear Implant Coating Material

Abstract Inner ear trauma caused by cochlear implantation is a severe clinical problem. It was shown that an electrode alginate coating can reduce the insertion forces in vitro. The grade of the alginate viscosity can be adjusted by using different metal ions for cross-linking the salts of the alginic acid. The aim was to investigate the stability and inner ear biocompatibility of alginate using different in vitro established cross-linkers. Alginate beads were cross-linked in either calcium chloride (CaCl2) or barium chloride (BaCl2) solution. The beads were cultivated in artificial perilymph and stability and swelling were observed for 13 months. Ototoxicity was tested on cochlear whole mount explants from neonatal rats. Neomycin served as positive control to induce hair cell damage and explants without any addition served as negative control. The beads and explants were co-cultured for 48 hours and the hair cell survival was analysed microscopically. Neomycin treatment induced an extensive inner and outer hair cell loss. Neither CaCl2 nor BaCl2 cross-linked alginate beads caused any damage to the hair cells. Even though the same volume of alginate and cross-linkers were used, in CaCl2 cross-linked beads were initially almost double the size of in BaCl2 cross-linked beads. None of the cross-linked alginate beads had a significant volume change within 3 months being cultured in artificial perilymph. After 3 months the CaCl2 cross-linked beads swelled massively and dissolved within one week whereas BaCl2 cross-linked alginate beads remained unchanged until month 13 after culture start. Alginate beads gelled with both cross-linkers are biocompatible with the inner ear sensory epithelium. Both cross-linkers ensure a stable gelation of alginate but a swelling followed by degradation of the in CaCl2 cross-linked beads occurred after 3 months. For coatings, which need to be long term stable, BaCl2 should be chosen whereas CaCl2 may be more suitable for applications where limited stability is needed and the swelling is not affecting the surrounding tissue. Therefore, BaCl2 cross-linking of alginate may be the best choice for cochlear implant coating.

Thermodynamic and experimental studies on removal of calcium and sulfate ions from recycling water of complex sulfide flotation operations

A chemical method for removing calcium sulfate saturated solutions (0.016 mol/L CaSO4) using barium chloride (BaCl2·2H2O) and sodium phosphate (Na3PO4) was experimentally studied. The main interest is to remove these ions from the solution through the precipitation of two solid species: sulfate (SO42−) as barite (BaSO4), and calcium (Ca2+) as hydroxyapatite (Ca5(PO4)3OH). Additionally, a solid/liquid separation method (i.e., flotation) was explored, using oleic acid and dodecylamine as collectors. The results show that, the chemical treatment of saturated solutions at 60 °C, pH 11.5 and using 3.9 g/L BaCl2·2H2O and 1.6 g/L Na3PO4, promotes the precipitation of barium sulfate and calcium-deficient hydroxyapatite (Ca10–x(HPO4)x(PO4)6–x(OH)2–x), with residual concentrations of calcium and sulfate below 0.10 and 5 mg/L, respectively. The residual calcium concentration increases to 28 mg/L when using the same amount of reactants, at temperature and pH values below those quoted. The highest flotation recovery of hydroxyapatite with oleic acid at pH 9.5 was about 80%, while that of barite floated with dodecylamine at pH 6.5 was about 90%.

Sympathetic activity is correlated with satellite cell aging and myogenesis via \u03b22-adrenoceptor

Background and objectiveSympathetic activity plays an important role in the proliferation and differentiation of stem cells, and it changes over time, thereby exerting differential effects on various stem cell types. Aging causes sympathetic hyperactivity in aged tissues and blunts sympathetic nerves regulation, and sympathetic abnormalities play a role in aging-related diseases. Currently, the effect of sympathetic activity on skeletal muscle stem cells, namely satellite cells (SCs), is unclear. This study aimed to investigate the effects of skeletal muscle sympathetic activity on SC aging and skeletal muscle repair.Materials and methodsTo evaluate skeletal muscle and fibrotic areas, numbers of SCs and myonuclei per muscle fiber, β2-adrenoceptor (β2-ADR) expression, muscle repair, and sympathetic innervation in skeletal muscle, aged mice, young mice that underwent chemical sympathectomy (CS) were utilized. Mice with a tibialis anterior muscle injury were treated by barium chloride (BaCl2) and clenbuterol (CLB) in vivo. SCs or C2C12 cells were differentiated into myotubes and treated with or without CLB. Immunofluorescence, western blot, sirius red, and hematoxylin–eosin were used to evaluate SCs, myogenic repair and differentiation.ResultsThe number of SCs, sympathetic activity, and reparability of muscle injury in aged mice were significantly decreased, compared with those in young mice. The above characteristics of young mice that underwent CS were similar to those of aged mice. While CLB promoted the repair of muscle injury in aged and CS mice and ameliorated the reduction in the SC number and sympathetic activity, the effects of CLB on the SCs and sympathetic nerves in young mice were not significant. CLB inhibited the myogenic differentiation of C2C12 cells in vitro. We further found that NF-κB and ERK1/2 signaling pathways were activated during myogenic differentiation, and this process could be inhibited by CLB.ConclusionNormal sympathetic activity promoted the stemness of SCs to thereby maintain a steady state. It also could maintain total and self-renewing number of SCs and maintain a quiescent state, which was correlated with skeletal SCs via β2-ADR. Normal sympathetic activity was also beneficial for the myogenic repair of injured skeletal muscle.