Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Thimerosal”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 595 records · Page 33Linked to original sources
PubMed2001

Modulation of ICl(Ca) in vascular smooth muscle cells by oxidizing and cysteine-reactive reagents.

The present study investigated the effect of redox agents on Ca2+-activated Cl- currents ( ICl(Ca)) recorded in smooth muscle cells isolated from rabbit portal vein. In perforated-patch experiments on portal vein cells the amplitude of ICl(Ca) evoked by either spontaneous release of Ca2+ from internal stores or Ca2+ influx through voltage-dependent Ca2+ channels was markedly and irreversibly enhanced by the non-specific oxidant, diamide (10-200 microM). Diamide also prolonged the decay of both currents. The reductant dithiothreitol had no effect on control ICl(Ca) but reversed the increase of current amplitude produced by diamide. Diamide also increased global intracellular Ca2+ at rest but had no effect on the time-course of Ca "sparks" determined by confocal microscopy. Diamide and the endogenous oxidant hydrogen peroxide increased the amplitude and prolonged the kinetics of ICl(Ca)evoked by pipette solutions containing free Ca2+ clamped at 500 nM. Similar effects were observed with the hydrophilic thiol-reactants thimerosal and p-chloromercuriphenylsulphonic acid (PCMPS). Therefore, the gating and activation of Ca2+-activated Cl- conductance is sensitive to redox modification.

4-Chloromercuribenzenesulfonate↗
PubMed2006

Production of endothelial nitric oxide synthase (eNOS) over-expressing piglets.

Vascular function, vascular structure, and homeostasis are thought to be regulated in part by nitric oxide (NO) released by endothelial cell nitric oxide synthase (eNOS), and NO released by eNOS plays an important role in modulating metabolism of skeletal and cardiac muscle in health and disease. The pig is an optimal model for human diseases because of the large number of important similarities between the genomic, metabolic and cardiovascular systems of pigs and humans. To gain a better understanding of cardiovascular regulation by eNOS we produced pigs carrying an endogenous eNOS gene driven by a Tie-2 promoter and tagged with a V5 His tag. Nuclear transfer was conducted to create these animals and the effects of two different oocyte activation treatments and two different culture systems were examined. Donor cells were electrically fused to the recipient oocytes. Electrical fusion/activation (1 mM calcium in mannitol: Treatment 1) and electrical fusion (0.1 mM calcium in mannitol)/chemical activation (200 microM Thimerosal for 10 min followed by 8 mM DTT for 30 min: Treatment 2) were used. Embryos were surgically transferred to the oviducts of gilts that exhibited estrus on the day of fusion or the day of transfer. Two cloned transgenic piglets were born from Treatment 1 and low oxygen, and another two from Treatment 2 and normal oxygen. PCR, RT-PCR, Western blotting and immunohistochemistry confirmed that the pigs were transgenic, made message, made the fusion protein and that the fusion protein localized to the endothelial cells of placental vasculature from the conceptuses as did the endogenous eNOS. Thus both activation conditions and culture systems are compatible with development to term. These pigs will serve as the founders for a colony of miniature pigs that will help to elucidate the function of eNOS in regulating muscle metabolism and the cardiorespiratory system.

Animals↗
PubMed2004

Update on side effects from common vaccines.

Vaccines have had a tremendous impact on public health by reducing morbidity and mortality from a variety of virulent pathogens. However, unintended side effects continue to pose a potential risk that may outweigh the vaccine's protective attributes. In this review, we discuss recent articles and controversies pertaining to vaccine-associated adverse events. Included in the discussion are influenza, hepatitis B, measles-mumps-rubella, diphtheria-tetanus-pertussis, polio, Haemophilus influenzae type b, and rotavirus vaccines. The importance and contribution of vaccine constituents (such as thimerosal) to side effects is also reviewed.

Adjuvants, Immunologic↗
PubMed1988

Purification and characterization of a Ca2+- or Mg2+-stimulated ATPase from plasma membrane enriched fractions of Dictyostelium discoideum.

Evidence is presented for the presence of both diethylstilbestrol (DES)-sensitive and DES-insensitive Mg2+-ATPase activities in plasma membrane enriched fractions of Dictyostelium discoideum. When removed from the membrane, the DES-sensitive activity is markedly less stable than the DES-insensitive activity, and the two activities display a number of quite distinct properties. The DES-sensitive enzyme has a decided preference for Mg2+ over Ca2+, displays saturation kinetics in response to ATP as substrate (Km = 0.2 mM) and has a narrow pH optimum range. In contrast, the DES-insensitive activity is stimulated equally by Mg2+ or Ca2+, is not saturable by ATP within the mM concentration range and has a much broader pH optimum. The DES-insensitive activity has been purified extensively. The purified enzyme is inhibited by vanadate and fluoride, but is insensitive to N,N'-dicyclohexylcarbodiimide (DCCD), N-ethylmaleimide and thimerosal. In the absence of divalent cations, the enzyme displays a sigmoidal activity curve in response to substrate concentration, which is abolished by addition of either Mg2+ or Ca2+, suggesting a binding site for a divalent cation and a positive cooperative interaction. The enzyme is capable of hydrolyzing other nucleotide triphosphates and ADP, but is without activity on AMP, p-nitrophenyl phosphate and pyrophosphate. The enzyme has an apparent molecular weight of approximately 64,000.

Adenosine Triphosphate↗
PubMed1978

The multiple forms and kinetic differences of rat colonic beta-N-acetylhexosaminidases.

Rat colonic beta-N-acetylhexosaminidase (2-acetamido-2-deoxy-beta-D-glucoside acetamidodeoxyglucohydrolase, EC 3.2.1.30) has been separated into three forms by DEAE-cellulose chromatography with an increasing salt gradient. It was not possible to separate the glucosaminidase activity from the galactosaminidase activity by a variety of chromatographic procedues, but the ratio of the two specific activities varied during purification. The pH optima were however identical, for both activities and all three forms. Kinetic measurements including inhibition by substrate analogues showed differences between the two activities as well as among the three forms. A common active site model was inconsistent with the results. Data from mixed substrate experiments were consistent with a model wherein the two activities reside in seperate active sites, each able to be inhibited by the substrate for the other site. The effect of acetate and SH reagents confirmed the two-site model. Treatment with neuraminidase, thimerosal, p-hydroxymercuribenzoate, HgCl2 and AgNO3 or heating at 50 degrees C did not produce any effect on the A form that could be identified as a conversion to the B form. Measurement of the effects on both activities supported the two-site model. It is concluded that the relationship between the A and B forms in the rat colonic mucosa hexosaminidases must be different from that reported for such enzymes from other sources.

Acetylglucosaminidase↗
PubMed1995

Characterization of the kinetics and distribution of N-arachidonylethanolamine (anandamide) hydrolysis by rat brain.

Arachidonoylethanolamide or 'anandamide' is a naturally occurring derivative of arachidonic acid that has been shown to activate cannabinoid receptors in the brain. Its metabolic inactivation by brain tissue has been investigated. Anandamide is hydrolyzed by the membrane fraction of rat brain homogenate to arachidonic acid and ethanolamine. The hydrolysis is temperature and pH- dependent (pH maximum at 8.5) and abolished by boiling. Anandamide hydrolysis is protein dependent in the range of 25-100 micrograms protein/ml; does not require calcium and is inhibited by phenylmethylsulfonylfluoride, diisopropylfluorophosphate, thimerosal and arachidonic acid. Hydrolysis of 10 microM anandamide by brain membranes follows first order kinetics; at 30 degrees C, the rate constant for anandamide catabolism is 0.34 min-1 mg protein-1. The Km for anandamide hydrolysis is 3.4 microM, and the Vmax is 2.2 nmol/min per mg protein. Hydrolysis occurs in all subcellular fractions except cytosol with the highest specific activity in myelin and microsomes. The distribution of anandamide hydrolytic activity correlates with the distribution of cannabinoid receptor-binding sites; the hippocampus, cerebellum and cerebral cortex exhibit the highest metabolic activity, while activity is lowest in the striatum, brain stem and white matter.

Amidohydrolases↗
PubMed1996

A novel diterpenoid labdane from Sideritis javalambrensis inhibits eicosanoid generation from stimulated macrophages but enhances arachidonate release.

The diterpenoid ent-8alpha-hydroxy-labda-13(16),14-dien ("labdane F2") was obtained from an anti-inflammatory extract of Sideritis javalambrensis. Labdane F2 inhibited prostaglandin E2 generation in cultured mouse peritoneal macrophages, treated with zymosan, ionophore A23187, or arachidonic acid itself, and in J774 macrophage-like cells activated by bacterial lipopolysaccharide (LPS). The mechanism was investigated by prelabelling the macrophages with radiolabelled arachidonic acid or oleic acid, followed by cell activation in the presence or absence of nontoxic concentrations of labdane F2. Surprisingly, under those conditions in which reduced PGE2 generation was observed, labdane F2 consistently enhanced the release of labelled fatty acid, in a manner similar to that displayed by thimerosal a known acyl-CoA: lysolecithin transferase inhibitor. Labdane E2 therefore appears to possess 2 mutually opposing actions on the eicosanoid system in macrophages: potentiation of delivery of substrate following cell activation, followed by inhibition of conversion of substrate to product. It was also found that nontoxic concentrations of labdane F2 reduced the expression of the inducible isoforms of cyclooxygenase and nitric oxide synthase in LPS-treated J774 cells. Thus, this anti-inflammatory diterpenoid labdane possesses a diverse array of effects impinging on enzyme pathways involved in eicosanoid generation and other inflammatory pathways in macrophages.

Animals↗
PubMed1992

Immunoassay of triiodothyronine in serum by time-resolved fluorometric measurement of europium-chelate complexes in solution.

We describe the development of a competitive immunoassay for triiodothyronine (T3) in serum. The assay combines immobilized antigens in microtitration wells with a biotinylated monoclonal anti-T3 antibody and a streptavidin-based universal detection reagent labeled with the Eu3+ chelator 4,7-bis(chloro-sulfophenyl)-1,10 phenanthroline-2,9-dicarboxylic acid (BCPDA). In the assay, T3 released from binding proteins by thimerosal competes with immobilized antigen for binding to a limited amount of antibody. The bound biotinylated antibody is identified by a subsequent reaction with the detection reagent, and fluorescence of the final complex is then quantified in solution after it has been dissociated from the solid support by the addition of a detergent solution. Evaluation of the method demonstrated good overall precision and appropriate detection limit (0.2 nmol/L) and dynamic range. Analytical recovery averaged 99.9%, and results of dilution experiments were in agreement with the expected values. Measurements by the present method correlated well with those by a commonly used radioimmunoassay.

Antibodies, Monoclonal↗
PubMed1983

Separation of VX-2 rabbit carcinoma-derived cells capable of releasing collagenase.

Primary and secondary cultures of VX-2 carcinoma produced high levels of collagenase activity in both active and latent forms in serum-free media. These cultures appeared morphologically heterogeneous in phase-contrast microscopy and revealed the presence of mainly three distinct forms: epithelial-like cells (E cells), fibroblast-like cells (F cells), and large rounded-flat cells which may represent a subclass of the F cells. Cell separation techniques such as brief dispase treatment, Percoll gradient centrifugation, thimerosal treatment, and rabbit serum were used to obtain predominantly one form or the other. The E cells never formed a monolayer but rather grew as limited size clusters of intimately associated cells with large nuclei and often appeared multinucleated. These cells were difficult to maintain in culture or serially passed more than a few times. The F cells, rare in early cultures but having the highest growth potential, appeared in various morphological forms ranging from spindle- to stellate-shaped cells. The cells in their third passage were capable of producing palpable tumors, similar in light and electron microscopic studies to the original tumor from which they were derived, when injected intramuscularly into recipient rabbits and produced specific collagenase activity in active and latent forms in serum-free media. Ultrastructural studies suggested that the E cells were of epithelial origin whereas the F cells were similar to stromal fibroblasts. Cytogenetic studies demonstrated that almost all of the E cells showed both numerical and structural chromosomal changes in a modal number of 54 chromosomes. On the other hand, the major cell population of the F cells resembled normal rabbit fibroblasts; both contained a normal diploid (2n = 44). However, few cells (4-6%) in the F-cell population were hyperdiploid with a modal chromosome number of 54. These cells may represent inadvertent contaminating E cells and account for the apparent limited turmorigenicity observed in early F-cell cultures. The data suggested that the E cells were of tumor origin whereas the majority of the F-cell population appeared to be of host origin. Furthermore, it is suggested that the E cells stimulate tumor-associated stromal cells to produce elevated levels of collagenolytic activity and contribute to collagen degradation during tumor invasion.

Animals↗
PubMed1984

An investigation of 2':3'-cyclic nucleotide 3'-phosphodiesterase (EC 3.1.4.37, CNP) in peripheral blood elements and CNS myelin.

Activity of 2':3'-cyclic nucleotide 3'-phosphodiesterase (CNP) of human erythrocyte membranes was determined in the presence of various brain CNP inhibitory compounds. Also, the hydrolysis of 2':3'-cAMP and 2':3'-cCMP by CNP of human platelets and lymphocytes was confirmed by thin layer chromatography and CNP activity was measured in lymphocytes, platelets, erythrocytes and CNS myelin. Human erythrocyte CNP activity was reduced 75 percent by the organomercurial p-chloromercuriphenyl sulfonate (1 X 10(-4) M), 46 percent by thimerosal (1 X 10(-4) M) and 35 percent by cupric chloride (1 X 10(-3) M). The 2'-AMP or 2'-CMP isomer was produced, exclusively, by the hydrolysis of 2':3'-cAMP or 2':3'-cCMP, respectively, by CNP of human lymphocytes and platelets and indicates a CNP-like activity is not only present in erythrocytes and the central and peripheral nervous systems, but also platelets and lymphocytes. CNP activities of human erythrocytes, human human and rat lymphocytes and human platelets were less than 4 percent of the activity of human and bovine CNS myelin.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗
PubMed1984

Action mechanism of the potent platelet aggregation inhibitor from Trimeresurus gramineus snake venom.

The platelet aggregation inhibitor (PAI) purified from T. gramineus snake venom inhibited platelet aggregation even when it was added after platelet shape change had occurred. It inhibited the initial platelet aggregation phase in rabbit platelet-rich plasma (PRP), but not the second lytic phase induced by thimerosal (0.5 mM), a -SH reagent. In human platelet-rich plasma, the venom inhibitor also inhibited the platelet aggregation induced by ADP, collagen, epinephrine or ristocetin. The epinephrine-induced platelet aggregation was more susceptible to the venom inhibitor. The venom inhibitor (10 micrograms/ml) as well as N-ethylmaleimide (1.2 mM), a -SH reagent, completely inhibited the thrombin-induced clot retraction of PRP. It is concluded that PAI acts on a common step of platelet aggregation. It acts on membrane -SH containing macromolecule which directly mediates the platelet aggregation subsequent to platelet shape change.

Animals↗
PubMed1996

Endothelium-derived hyperpolarizing factor: a key mediator of the vasodilator action of bradykinin.

Bradykinin causes vasodilatation by stimulating the production of vasodilator prostanoids and nitric oxide (NO). However, there is an additional component that is mediated by a diffusible endothelium-derived hyperpolarizing factor (EDHF). The non-selective inhibitor of arachidonic acid metabolism eicosatetraynoic acid inhibits the EDHF-mediated component of the relaxation to bradykinin. Therefore, EDHF may be an archidonic acid metabolite. The diffusible nature of EDHF has been disputed because of the inability to consistently detect the factor using perfusion bioassay techniques. However, administration of the acyltransferase inhibitor thimerosal facilitates the release of EDHF by endothelial cells in culture. Further studies are warranted to identify EDHF and explore further its functions in vasomotion.

5,8,11,14-Eicosatetraynoic Acid↗
PubMed1982

Comparison of biochemical properties of platelet monoamine oxidase in mentally disordered and healthy individuals.

We have investigated some biochemical properties of platelet monoamine oxidase (MAO) isolated from chronic schizophrenic and agoraphobic patients, nonschizophrenic institutional controls, and healthy volunteers. The enzyme activity level in the healthy population was reasonably constant over at least a 6-week period. High correlations were found between MAO activity assessed for different substrates (p-tyramine, beta-phenylethylamine, and tryptamine). Some heterogeneity of the platelet MAO may exist, however, at least in some of the chronic schizophrenics, since the substrate specificities were changed and the Km values reduced. The half-life of the enzyme at 58 degrees C was 2-3 minutes and the transition temperature derived from Arrhenius plots was 16-17 degrees C with respect to beta-phenylethylamine. Platelet MAO from chronic schizophrenics was not significantly different from control values with respect to temperature effects. SDS-polyacrylamide gel electrophoresis of the 3H-pargyline-MAO adduct revealed that the subunit of platelet MAO is a single band protein with a molar individuals. The adjacent structure of the flavine site of the platelet MAO was chromatographically identical to the penta-peptide isolated from MAOs from other tissues. The response of platelet MAO to thimerosal, a new differential type A MAO inhibitor, could be distinguished not only from type A MAO isolated from human placenta, but also from type B MAO isolated from bovine liver.

Agoraphobia↗
PubMed1994

Effects of endothelium removal by saponin and of oxyhemoglobin on canine cerebrovascular responses.

The stainless steel cannula method was applied to isolated and perfused canine basilar arteries to examine the role of endothelium in the responses to intraluminal vasoactive substances. After intraluminal treatment with saponin to remove the endothelium, the monophasic constrictions to potassium chloride and prostaglandin F2 alpha were potentiated, while those to phenylephrine (alpha 1-adrenoceptor agonist) and 5-hydroxytryptamine were not changed. Xylazine (alpha 2-adrenoceptor agonist) and acetylcholine induced a constriction preceded by a small dilation in controls. The response to xylazine was not modified, while the constriction to acetylcholine was augmented after endothelium removal. Bradykinin, substance P and vasopressin caused a dilation in lower doses, and a dilation followed by a secondary constriction in higher doses in controls. The dilations to these peptides were reduced and the constrictions were enhanced after endothelial removal. Adenosine triphosphate produced a biphasic response, i.e., a dilation followed by a constriction, which was occasionally preceded by a small constriction in higher doses, and only the dilation in lower doses was attenuated. The monophasic dilation to adenosine was potentiated, while the papaverine-induced dilation was not influenced by endothelial removal. After extraluminal treatment with oxyhemoglobin, the dilations to calcium ionophore A23187 and thimerosal were attenuated, while the constriction to acetylcholine was enhanced. The dilations to substance P and vasopressin were depressed, and the constrictions were potentiated. The monophasic dilation to sodium nitroprusside was augmented, while that to papaverine was not changed. These results suggest that the endothelium may play important roles not only in producing endothelium-derived relaxing factors but also in modulating the calcium influx into the smooth muscle cells. The mechanisms of altered responsiveness might be implicated in cerebral vasospasm following subarachnoid hemorrhage.

Animals↗
PubMed1994

Studies on the properties of myo-inositol-1,4,5-trisphosphate 5-phosphatase and myo-inositol monophosphatase in bovine iris sphincter smooth muscle: effects of okadaic acid and protein phosphorylation.

In bovine iris sphincter, myo-inositol 1,4,5-trisphosphate (IP3) 5-phosphatase and myo-inositol 1-phosphate (IP1) monophosphatase are mainly localized in the microsomal and soluble fractions, respectively. Studies on the properties of these enzymes can be summarized as follows. (1) The microsomal IP3 5-phosphatase hydrolyzed IP3 to myo-inositol 1,4-bisphosphate with an apparent Km of 28 microM and Vmax of 32 nmol/min per mg protein. The IP1 monophosphatase in the soluble fraction hydrolyzed IP1 into free inositol with an apparent Km of 89 microM and Vmax of 7 nmol/min per mg protein. (2) IP3 5-phosphatase and IP1 monophosphatase had optimal pH values at 8.0 and 7.0, respectively. (3) Both enzymes required Mg2+ and their highest specific activities were at a cation concentration of 2 mM. (4) Ca2+ (> 0.5 microM) exerted an inhibitory effect on IP3 5-phosphatase activity, and marked inhibition (47%) was observed at a concentration of 10 microM. Higher concentrations of the cation (> 100 microM) were required to inhibit IP1 monophosphatase. (5) IP1 monophosphatase, but not IP3 5-phosphatase, was inhibited by Li+. Li+ had no effect on the contractile response in this smooth muscle. (6) Both enzymes were inhibited by ATP and by the thiol-blocking agent, disulfiram. In addition, thimerosal, a thiol reagent, also inhibited the IP3 5-phosphatase activity. (7) Protein phosphorylation of the microsomal and soluble fractions with PKA or PKC had no effect on the activities of these enzymes. (8) Okadaic acid, a protein phosphatase inhibitor, had no effect on the activity of IP3 5-phosphatase. However, in the intact iris sphincter the toxin significantly reduced the carbachol-induced IP3 production, 1,2-diacylglycerol formation, measured as phosphatidic acid, and caused muscle relaxation.

Animals↗
PubMed1987

Glutaraldehyde inactivated pertussis vaccine: a safe vaccine in the innocuity test.

The adsorbed diphtheria-pertussis-tetanus (DPT) vaccine containing glutaraldehyde inactivated pertussis vaccine passed the innocuity test only after one month's storage of the preparation at 4-8 degrees C when the adsorbed DPT vaccine containing pertussis vaccine inactivated by heat, formaldehyde, thimerosal or acetone did not pass the test. The adsorbed DPT vaccine became innocuous when it was stored at 4-8 degrees C. The innocuity test was passed more easily in guinea pigs than in mice.

Animals↗
PubMed1996

Calcium-dependent action of hypertrehalosemic hormone on activation of glycogen phosphorylase in cockroach fat body.

Signaling mechanisms for Blaberus discoidalis hypertrehalosemic hormone (Bld-HrTH)-dependent glycogen phosphorylase activation were investigated in vitro using fat body of the tropical cockroach, B. discoidalis. Brief treatment of fat bodies with Bld-HrTH in the absence of extracellular Ca2+ showed a significant activation of phosphorylase. Although extracellular Ca2+ was required for a full activation of phosphorylase by Bld-HrTH, stimulation in the absence of extracellular Ca2+ suggested that intracellular Ca2+ was also involved in Bld-HrTH signal transduction. Thapsigargin and thimerosal mobilize Ca2+ from intracellular stores by different mechanisms, and both chemicals stimulated phosphorylase activities as effectively as a maximum dose of Bld-HrTH. Bld-HrTH likely induces intracellular Ca2+ release followed by extracellular Ca2+ entry across the plasma membrane. Inositol-1,4,5-trisphosphate (InsP3) levels were greatly increased by Bld HrTH in a time- and dose-dependent manner, suggesting that InsP3 might be a Ca(2+)-mobilizing intracellular second messenger for Bld-HrTH.

Animals↗
PubMed1996

Mechanisms of intracellular calcium regulation in adult astrocytes.

Microfluorimetric techniques were used to measure changes in intracellular calcium in astrocytes cultured from the forebrain of the adult rat. Application of ATP consistently raised intracellular calcium. The response persisted in the absence of extracellular calcium, but then quickly declined upon repeated agonist application. Thapsigargin abolished responses to nucleotides following depletion of the endoplasmic reticular calcium stores. Calcium release was inhibited by caffeine, but was dramatically increased through inositol phosphate receptor sensitization by the sulphydryl reagent thimerosal. Responses to repeated nucleotide applications resulted in a gradual decline of peak calcium concentrations, suggesting a (post)receptor-mediated desensitization or gradual depletion of the internal calcium stores. Subsequent application of ionomycin suggested intracellular calcium depletion as the relevant mechanism. Depletion of the internal calcium stores with ATP, ionomycin or thapsigargin failed to reveal a calcium influx pathway. These results suggest that the capacitative mechanism of calcium entry does not operate in response to nucleotide receptor activation in these cells, and that the immediate refilling of the internal calcium stores is primarily determined by re-uptake of cytosolic calcium into the endoplasmic reticulum. A complete refilling of this calcium store by extracellular calcium may be a much slower process. Control of these signal transduction pathways is crucial to the maintenance of the calcium/energy homeostasis of the adult astrocyte in the central nervous system.

Adenosine Triphosphate↗