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At least 757 records · Page 42Linked to original sources
PubMed2006

[Inhibition of human macrophage-derived foam cell differentiation by blocking Kv1.3 and Kir2.1 channels].

OBJECTIVE: To investigate the expression of Kv1.3 and Kir2.1 during human monocyte-derived macrophages differentiation into foam cells and their function in foam cells formation. METHODS: The human macrophage-derived foam cells were obtained by incubating macrophages with ox-LDL (30 mg/L) for 60 h. The expression of Kv1.3 and Kir2.1 channels were examined by immunocytochemistry, RT-PCR and Western blot. Effects of channel blockers (rMargatoxin and BaCl2) on the cellular cholesterol metabolism were studied by measuring the cellular contents of total cholesterol (TC), free cholesterol (FC), and cholesterol ester (CE) in the presence or absence of the channel blockers. RESULTS: After incubating macrophages with 30 mg/L ox-LDL for 60 h, the cellular contents of TC, FC and CE were markedly increased and the ratio of CE/TC was raised from (14.4+/-6.8)% to (57.9+/-3.5)% (P<0.05), which indicated that the cells had differentiated into foam cells. The expression of Kv1.3 and Kir2.1 channels appeared no obvious difference when differentiating into foam cells (P>0.05); After being blocked specifically (rMargatoxin: 0.1, 10 nmol/L; BaC(12): 75, 125 micromol/L), the cellular contents of TC and CE were markedly reduced without exception and the ratios of CE/TC were all less than 50% (P<0.05). CONCLUSION: Both Kv1.3 and Kir2.1 channels play a critical role in differentiation of macrophages into foam cells and blockage of corresponding potassium channels would prevent the formation of the foam cells.

Barium Compounds↗
PubMed1991

[Anti-arrhythmia and vegetative nervous system effects of anisodamine].

Anisodamine (Ani) is an alkaloid first isolated in China from the root of Anisodus tanguticus. Ani 10, 15 mg.kg-1 i.v. markedly shortened the duration of arrhythmias induced by aconitine (10 micrograms.kg-1 i.v.) or by BaCl2 (2 mg.kg-1 i.v.) in anesthetized rats. Ani significantly effected on arrhythmias induced by early coronary artery ligation in rats by reducing total numbers of ectopic beats and shortening the duration of ventricular tachycardia and ventricular fibrillation 30 min after coronary ligation. The incidence of ventricular fibrillation of mice induced by chloroform were reduced from 100% to 20% and 10% by i.v. Ani 1 and 10 mg.kg-1 respectively. Ani 0.05, 0.25 mumol.L-1 prolonged the duration of neurologic refractory period of isolated guinea pig left atria and 10 mg.kg-1 i.v. had no effect on tachycardia induced by i.v. isoproterenol (0.01 mg.kg-1) but blocked the stimulation of nervi vagus. After i.v. Ani 15 mg.kg-1 P-P, P-R and QT-c intervals on the ECG were prolonged. Mean arterial pressure and diastolic pressure were reduced but systolic pressure was not effected.

Aconitine↗
PubMedDate not supplied

[The evaluation of the presumed mutagenic activity of barium nitrate].

Barium nitrate, which is used in industry in the production of green signal lights, to remove gases from vacuum tubes, and in the production of barium oxide, was assayed to assess the possible mutagenic effects using both the Ames test (S. typhimurium TA 1535, TA 1537, TA 1538, TA 97a, TA 98, TA 100, TA 102c), with and without metabolic activation with the plate incorporation assay and pre-incubation assay methods, and using the mitotic crossing over test, the mitotic genic conversion test, and the retromutation test in Saccharomyces cerevisiae, D7 strain, with and without metabolic activation. In the experimental conditions of the study, at various gradually increasing concentrations, barium nitrate gave negative results.

Barium↗
PubMed1991

Progress in the development of a PET scanner based on BaF2 scintillator and photosensitive wire chambers.

The work presented is part of a design study for a Positron Emission Tomograph (PET) scanner based on the use of BaF2 scintillator and photosensitive wire chambers. The detection efficiency for gamma radiation of 511 keV is found close to 100% for a sufficiently large crystal. For a matrix of small and elongated crystals as one would use in a PET scanner (5 x 5 x 50 mm3) we obtained 6 photoelectrons per 511 keV deposited. The following variants and alternatives were also studied: operation of the wire chamber at atmospheric pressure; double readout where the crystals are read on one side with a photomultiplier to give time and energy resolution, and on the other side with a wire chamber to localise the event; and Csl photocathodes. Encouraging results have been obtained for each of these, but particularly the Csl photocathodes look very promising.

Animals↗
PubMed1991

Development of a BaF2/TMAE PET system.

A detector has been developed for position sensitive registration of annihilation radiation. The 511 keV gamma rays are detected in a set of BaF2 scintillation crystals coupled to low pressure TMAE-filled photosensitive multi wire chambers. In a first experimental detector with two BaF2 crystals we obtained a detection efficiency for 511 keV quanta of 42%. The position resolution is 5 mm and the time resolution is 4 ns. At present a circular detector for three BaF2 crystals with a diameter of 28 cm, each with a thickness of 8 mm, is under construction. Position sensitivity is obtained by means of delayline read out of cathode wires. Detectors of this type can be used as building blocks for a PET system. We are performing simulations of a system consisting of six rectangular detectors in a hexagonal composition. Results are given and a discussion of further innovative developments is presented.

Barium↗
PubMed1991

[Reactivity of sevoflurane with carbon dioxide absorbents--comparison of soda lime and Baralyme].

The reactivity of sevoflurane with carbon dioxide absorbents, soda lime and Baralyme which are commercially available carbon dioxide absorbents, was studied. A closed circuit system which was made only for this investigation was set up without rubber. Sevoflurane 5% was circulated for 17 hours. The circulated gas was analyzed by gas chromatography (GC) and degradation products were identified by a gas chromatography-mass spectroscopy (GC-MS) as fluoromethyl 2-methoxy-2, 2-difluoro-1-(trifluoromethyl) ethyl ether, fluoromethyl 2-methoxy-2-fluoro-1-(trifluoromethyl) vinyl ether, and its isomer. These degradation products of sevoflurane from soda lime and Baralyme were the same substances. The rate of degradation by soda lime was 0.88% +/- 0.306, while that by Baralyme was 3.40% +/- 0.501. Baralyme decomposed sevoflurane about four times more than soda lime. There are two possible explanations for these results. One is the Baralyme contains more potassium hydroxide than soda lime. The other is that soda lime absorbs sevoflurane more because it contains more silica.

Absorption↗
PubMed1991

[Calcium dependence of the contractile response of the aorta in the rat, rabbit and guinea pig and in the human uterine artery].

The influence of extracellular Ca2+ on the contraction produced by noradrenaline (NA) (3 x 10(-6) M), KCl (60 mM) and BaCl2 (30 mM) on human uterine arteries (AUH) and aortic strips from rats, rabbits and guinea-pigs have been studied. The vessels were cut spirally and incubated in Krebs solution containing 2.5 mM Ca2+ (KN), 0 mM Ca2+ (K-0Ca) or 0 mM Ca2+ + 3 mM EDTA (K-EDTA). Both phases (fast and slow) of the response of aortic strips to NA and of the AUH to NA, KCl and BaCl2 were significantly smaller in solutions without Ca2+. Only in rabbit aortic strips the slow phase was significantly more reduced than the fast phase. Overall, the contractions of the rat aortic strips were most resistant to the absence of extracellular Ca2+. These results confirm the variability of the responses of blood vessels from different vascular beds and species to the removal of extracellular Ca2+.

Animals↗
PubMed1990

Effects of verapamil on synaptic transmission in mammalian sympathetic ganglia.

Effects of verapamil (Ver) on the synaptic transmission of isolated superior cervical ganglia (SCG) were investigated by means of intracellular recording techniques. In the neurons of SCG of rabbits and guinea pigs, Ver (100-400 mumol/L) depressed both the synaptic responses (f-EPSPs and/or evoked action potentials) elicited by orthodromic stimulation and the acetylcholine (ACh) potentials induced by pressure ejection of ACh. 4-Aminopyridine (4-AP, 100 mumol/L) and BaCl2 (5 mmol/L) facilitated the f-EPSPs inhibited by Ver, but had no notable effect on the ACh potentials depressed by Ver. Ver suppressed the ACh potentials enhanced by pyridostigmine (1 mumol/L). The potentiating effect of soman (1 mumol/L) on the ACh potentials was prevented by Ver. It is suggested that Ver can block the synaptic transmission of mammalian SCG by both the pre- and postganglionic mechanisms.

Action Potentials↗
PubMed1991

Ion-chromatographic determination of L-tartrate in urine samples.

We propose using ion chromatography to determine tartrate concentration in urine. A 100-microL sample of urine is diluted and injected into the chromatograph. Tartrate is eluted within 11.5 min as a distinct and well-resolved peak. The sensitivity of the standard procedure (signal-to-noise ratio, 3/1) is 30 mumol/L. The intra-run and interrun coefficients of variation are 2.5% and 4.1%, respectively. Mean analytical recovery of known amounts of added tartrate ranges between 94.2% and 104.0%. We investigated the specificity of the procedure by analyzing urine containing added dicarboxylic acids structurally related to tartrate. The reliability of the procedure makes it suitable for investigating tartrate metabolism, e.g., the potential role of tartrate as an inhibitor of crystallization in calcium nephrolithiasis.

Adult↗
PubMed1991

A simple histochemical technique for the identification of gunshot residue.

Alizarin red S (ARS) is a commonly used organic dye useful in the histologic identification of calcium deposits. ARS also forms colored reaction products with other metal ions, including barium and lead, which are present in primer residue. In histochemical studies, ARS is shown to identify primer residues from several manufacturers as well as primer residue deposited in tissue, either experimentally or in close-range gunshot wounds. This can be easily accomplished with routine histologic techniques. ARS does not stain gunpowder residue, tattoo pigment, melanin, graphite, india ink, or anthracotic pigment.

Anthraquinones↗
PubMed1990

A double perfusion system with two-channel recording for the simultaneous study of the contractile responses of the circular and longitudinal smooth muscle layers of the rat vas deferens.

A device for double perfusion of the vas deferens externally and through the lumen is described in detail. The perfusion system allows the simultaneous recording of drug-induced or spontaneous contractions of the circular and longitudinal smooth muscle layers of the organ. Isometric contractions of the longitudinal (external) layer are recorded through a tension transducer. The contractions of the circular (internal) smooth muscle layer are recorded as changes of the pressure of internal perfusion. Therefore, four different effects can be recorded for a given concentration of agonist by combining the variables related to the route of perfusion (external or internal) and type of muscle (longitudinal or circular). In addition, antagonism or synergism can be studied by simultaneously perfusing a second drug. Results can be expressed as single records or as mean concentration-response curves from which drug-receptor parameters can be directly or indirectly obtained. The importance of employing this method for the analysis of some less usual problems related to the mechanism of drug action is discussed.

Animals↗
PubMed1990

[Anti-arrhythmic effects of matrine].

Matrine (MT) is an alkaloid isolated from Sophra alopecuroids L. The LD50 of MT iv to mice was 72.1 mg/kg (95% CL 68.2-76.5 mg/kg). MT had significant effects on different experimental models of arrhythmias induced by aconitine, barium chloride or coronary ligation. The ECG of anesthetized rats was significantly changed after iv of MT. The HR was retarded and the PR and QTc intervals were prolonged.

Aconitine↗
PubMedDate not supplied

[Mutagen activity of barium chloride in Salmonella typhimurium].

Barium chloride, which is an important industrial chemical used in pigments, lacquers, dyes, glass and pesticide production, leather tanning and cloth dying, was tested on Salmonella typhimurium (TA 1535, TA 1537, TA 1538, TA 97, TA 98, TA 100) with the reverse mutation test, with and without metabolic activation, to assess its possible genotoxic effects and any possible action with respect to standard mutagens (sodium azide, 9-aminoacridine, 2-nitrofluorene, mitomycine-C, 2 aminoacridine). Using the platelet incorporation technique, barium chloride at various progressive concentrations gave negative results under the experimental conditions of the study.

Barium↗
PubMed1990

[A comparison of anti-arrhythmic effects of four kinds of rhizoma seu radix Nomopterygii].

Experiments were conducted to compare the anti-arrhythmic effects of the four kinds of Qianghuo(Notopterygium incisum; N. forbesii; Pleurospermum rivulorum; Angelica silvestris). It has been found that all the four kinds of Qianghuo can antagonize arrhythmia induced by aconitine. Notopterygium incisum can prolong the ventricular vibration induced by CaCl2 and Pleurospermum rivulorum can prolong the ventricle stop induced by BaCl2. Thus Qianghuo can be used as a sedative and anti-arrhythmic drug.

Aconitine↗
PubMed1990

Carcinogenic sulfide salts of nickel and cadmium induce H2O2 formation by human polymorphonuclear leukocytes.

Some derivatives of nickel, cadmium, and cobalt are carcinogenic in humans and/or animals but their mechanisms of action are not known. We show that they are capable of stimulating human polymorphonuclear leukocytes (PMNs), as measured by H2O2 formation, a known tumor promoter. Most effective were the carcinogens nickel subsulfide, which caused a 550% net increase in H2O2 over that formed by resting PMNs, followed by cadmium sulfide, 400%, and nickel disulfide, 200%. Nickel sulfide and cobalt sulfide caused statistically nonsignificant increases of 45 and 20%, respectively. Noncarcinogenic barium and manganese sulfides, and sulfates of nickel, cadmium, and cobalt were inactive. The enhancement of H2O2 formation by CdS and Ni3S2 (1 mumol/2.5 x 10(5) PMNs) was comparable to that mediated by the potent tumor promoter 12-O-tetradecanoylphorbol-13-acetate, used at 0.5 and 1 nM, respectively. Concurrent treatment of 12-O-tetradecanoylphorbol-13-acetate-stimulated PMNs with Ni3S2 or NiS caused a decrease in H2O2 accumulation from that expected if the effects were additive. Including catalase in the reaction mixture proved that the oxidant formed by stimulated PMNs was H2O2, whereas adding superoxide dismutase showed that superoxide was also present in PMN samples treated with NiS but not with Ni3S2. Since nickel- and cadmium-containing particulates are deposited in the lungs and cause infiltration of PMNs, the ability to activate those cells and induce H2O2 formation may contribute to their carcinogenicity.

Barium↗
PubMed1990

[Antiarrhythmic effect of Oenanthe javanica (Bl.) DC. injection].

The antiarrhythmic effect of Shuiqin (Oenanthe javanica) injection was studied in rats. An injection of 3 ml/kg iv could significantly antagonize the arrhythmias induced by aconitine and BaCl2, and decrease the rates of ventricular fibrillation and death induced by CaCl2. The results suggest that Shuqin injection has a significant antiarrhythmic effect on experimental rats.

Aconitine↗
PubMed1990

[Protective action of Salvia miltiorrhiza aqueous extract on chemically induced acute myocardial ischemia in rats].

Aqueous extract of Salvia miltiorrhiza (SM-H) can protect the acute myocardial ischemia and arrhythmia of Sprague-Dawley rats induced by isoproterenol (ISO) or BaCl2 with the following results: (1) intraperitoneal injection (i.p.) of SM-H for 3 to 5 days or intravenously (i.v.) just once significantly reduced the death rate of the animals, (2) i.v. SM-H pretreatment significantly increased the lethal dose of BaCl2 infusion, (3) i.p. SM-H significantly decreased premature ventricular contraction, ventricular fibrillation, bradycardia and mortality rate induced by bolus i.v. of BaCl2, and (4) i.p. SM-H also significantly reduced ECG J-point displacement of rats induced by ISO.

Animals↗