Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: CAS:7440-70-2 (calcium)
 333,191 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of intracellular pH (pH(i)) on intracellular Ca2+ concentration ([Ca2+]i) vary in different cells, and mechanisms underlying these effects are still not clear. In the experiments reported here, the effects of changes in pH(i) produced by ammonium chloride and butyric acid were studied in enzymatically dispersed acinar cells of rat parotid glands. The changes in pH(i) and [Ca2+]i were estimated using the fluorescent dyes biscarboxyethyl-5,6-carboxyfluorescein (BCECF) and fura-2, respectively. pH(i) was altered using NH4Cl, butyric acid, or propionic acid while keeping the external pH constant at 7.4. NH4Cl (20 mM) applied for 4-5 min increased pH(i) from 7.18 to 7.79 (a decrease of proton concentration, [H+]i, from 66 to 16 nM) and produced a transient [Ca2+]i increase followed by a small sustained decrease. On the other hand, butyric acid (20 mM) decreased pH(i) from 7.16 to 6.81 (an increase of [H+]i from 69 to 155 nM) and produced a small sustained increase in [Ca2+]i. Washing out the butyric acid 4 min after application induced the recovery of pH(i) from 6.93 to 7.43 (a decrease of [H+]i from 118 to 37 nM) and a further transient increase in [Ca2+]i. The removal of external Ca2+ had little effect on changes in pH(i) produced by NH4Cl or butyric acid, but markedly reduced both the sustained and transient components of [Ca2+]i response. Cyclopiazonic acid (0.3 microM), an inhibitor of Ca2+ pump in intracellular stores, abolished the transient [Ca2+]i increase produced by the application of NH4Cl or withdrawal of butyric acid. These results suggest that a decrease in [H+]i, not the absolute level of [H+]i may release Ca2+ from intracellular stores.
 ...
PMID:Changes in intracellular Ca2+ concentration produced by the alteration of intracellular pH in rat parotid acinar cells. 915 41

The role of diet in the aetiology and pathogenesis of ulcerative colitis (UC) remains uncertain. Impaired utilization by colonocytes of butyrate, a product of bacterial fermentation of dietary carbohydrates escaping digestion, may be important. Sulphur-fermenting bacteria may be involved in this impaired utilization. Oxidative stress probably mediates tissue injury but is probably not of causative importance. Patients with UC are prone to malnutrition and its detrimental effects. However, there is no role for total parenteral nutrition and bowel rest as primary therapy for UC. The maintenance of adequate nutrition is very important, particularly in the peri-operative patient. In the absence of massive bleeding, perforation, toxic megacolon or obstruction, enteral rather than parenteral nutrition should be the mode of choice. Nutrients may be beneficial as adjuvant therapy. Butyrate enemas have improved patients with otherwise recalcitrant distal colitis in small studies. Non-cellulose fibre supplements are of benefit in rats with experimental colitis. Eicosapentaenoic acid in fish oil has a steroid-sparing effect which, although modest, is important, particularly in terms of reducing the risk of osteoporosis, but it seems to have no role in the patient with inactive disease. gamma-Linolenic acid and anti-oxidants also are showing promise. Nutrients may also modify the increased risk of colorectal carcinoma. Oxidative stress can damage tissue DNA but there are no data published at present on possible protection from oral anti-oxidants. Butyrate protects against experimental carcinogenesis in rats with experimental colitis. Folate supplementation is weakly associated with decreased incidence of cancer in UC patients when assessed retrospectively. Vigilance should be maintained for increased micronutrient requirements and supplements given as appropriate. Calcium and low-dose vitamin D should be given to patients on long-term steroids and folate to those on sulphasalazine.
 ...
PMID:Nutrition and ulcerative colitis. 919 66

The effects of commercially available calcium supplements (calcium carbonate, calcium gluconate, oyster shell preparation and bovine bone preparation) and gluconic acid on the absorption of calcium and magnesium were evaluated for 30 days in male Wistar rats. There were no differences in the apparent absorption ratio of calcium among rats fed each calcium supplement; however, the rats fed the calcium gluconate diet had a higher apparent absorption ratio of magnesium than the rats fed the other calcium supplements. Dietary gluconic acid also more markedly stimulated magnesium absorption than the calcium carbonate diet, and the bone (femur and tibia) magnesium contents of rats fed the gluconic acid diet were significantly higher than those of the rats fed the calcium carbonate diet. Furthermore, the weight of cecal tissue and the concentrations of acetic acid and butyric acid in cecal digesta of rats fed the calcium gluconate diet or the gluconic acid diet were significantly increased. We speculate that the stimulation of magnesium absorption in rats fed the calcium gluconate diet is a result of the gluconic acid component and the effect of gluconic acid on magnesium absorption probably results from cecal hypertrophy, magnesium solubility in the large intestine and the effects of volatile fatty acids on magnesium absorption.
 ...
PMID:The effect of calcium gluconate and other calcium supplements as a dietary calcium source on magnesium absorption in rats. 920 82

Modes of action of anthelmintic drugs are described. Some anthelmintic drugs act rapidly and selectively on neuromuscular transmission of nematodes. Levamisole, pyrantel and morantel are agonists at nicotinic acetylcholine receptors of nematode muscle and cause spastic paralysis. Dichlorvos and haloxon are organophosphorus cholinesterase antagonists. Piperazine is a GABA (gamma-amino-butyric acid) agonist at receptors on nematode muscles and causes flaccid paralysis. The avermectins increase the opening of glutamate-gated chloride (GluCl) channels and produce paralysis of pharyngeal pumping. Praziquantel has a selective effect on the tegument of trematodes and increases permeability of calcium. Other anthelmintics have a biochemical mode of action. The benzimidazole drugs bind selectively to beta-tubulin of nematodes, cestodes and fluke, and inhibit microtubule formation. The salicylanilides: rafoxanide, oxyclozanide, brotianide and closantel and the substituted phenol, nitroxynil, are proton ionophores. Clorsulon is a selective antagonist of fluke phosphoglycerate kinase and mutase. Diethylcarbamazine blocks host, and possibly parasite, enzymes involved in arachidonic acid metabolism, and enhances the innate, nonspecific immune system.
 ...
PMID:Modes of action of anthelmintic drugs. 926 48

Current frontline antiepileptic drugs tend to fall into several cellular mechanistic categories, and these categories often correlate with the clinical spectrum of action of the various antiepileptic drugs. Many antiepileptic drugs effective in control of partial and generalized tonic-clonic seizures are use- and voltage-dependent blockers of sodium channels. This mechanism selectively dampens pathologic activation of sodium channels, without interacting with normal sodium channel function. Examples include phenytoin, carbamazepine, valproic acid, and lamotrigine. Many antiepileptic drugs effective in control of generalized absence seizures block low threshold calcium currents. Low threshold calcium channels are present in high densities in thalamic neurons, and these channels trigger regenerative bursts that drive normal and pathologic thalamocortical rhythms, including the spike wave discharges of absence seizures. Examples include ethosuximide, trimethadione, and methsuximide. Several antiepileptic drugs that have varying clinical actions interact with the gamma-amino-butyric acid (GABA)ergic system. Diazepam and clonazepam selectively augment function of a subset of GABAA receptors, and these drugs are broad-spectrum antiepileptic drugs. In contrast, barbiturates augment function of all types of GABAA receptors, and are ineffective in control of generalized absence seizures, but effective in control of many other seizure types. Tiagabine and vigabatrin enhance cerebrospinal levels of GABA by interfering with reuptake and degradation of GABA, respectively. These antiepileptic drugs are effective in partial seizures. Lamotrigine is effective against both partial and generalized seizures, including generalized absence seizures. Its sole documented cellular mechanism of action is sodium channel block, a mechanism shared by phenytoin and carbamazepine. These drugs are ineffective against absence seizures. Consequently, unless there are unique aspects to the sodium channel block by lamotrigine, it seems unlikely that this mechanism alone could explain its broad clinical efficacy. Therefore, lamotrigine may have as yet uncharacterized cellular actions, which could combine with its sodium channel blocking actions, to account for its broad clinical efficacy.
 ...
PMID:Antiepileptic drug cellular mechanisms of action: where does lamotrigine fit in? 942 23

CC chemokine receptors 1 and 3 (CCR1 and CCR3) are expressed by eosinophils; however, factors regulating their expression and function have not previously been defined. Here we analyze chemokine receptor expression and function during eosinophil differentiation, using the eosinophilic cell line HL-60 clone 15 as a model system. RNA for CCR1, -3, -4, and -5 was not detectable in the parental cells, and the cells did not specifically bind CC chemokines. Cells treated with butyric acid acquired eosinophil characteristics; expressed mRNA for CCR1 and CCR3, but not for CCR4 or CCR5; acquired specific binding sites for macrophage-inflammatory protein-1alpha and eotaxin (the selective ligands for CCR1 and CCR3, respectively); and exhibited specific calcium flux and chemotaxis responses to macrophage-inflammatory protein-1alpha, eotaxin, and other known CCR1 and CCR3 agonists. CCR3 was expressed later and at lower levels than CCR1 and could be further induced by IL-5, whereas IL-5 had little or no effect on CCR1 expression. Consistent with the HIV-1 coreceptor activity of CCR3, HL-60 clone 15 cells induced with butyric acid and IL-5 fused with HeLa cells expressing CCR3-tropic HIV-1 envelope glycoproteins, and fusion was blocked specifically by eotaxin or an anti-CCR3 mAb. These data suggest that CCR1 and CCR3 are markers of late eosinophil differentiation that are differentially regulated by IL-5 in this model.
 ...
PMID:CC chemokine receptors 1 and 3 are differentially regulated by IL-5 during maturation of eosinophilic HL-60 cells. 957 May 58

Chemical characteristics of developing neurons in the superior olivary complex of the ferret were analyzed using immunohistochemical methods. The present report of calcium-binding proteins in the developing and adult superior olivary complex shows distinct distribution patterns for parvalbumin, calbindin, and calretinin in the lateral superior olivary nucleus (LSO) of the developing ferret that correspond to distribution patterns for different projection cell types and neurotransmitters. In the neonate, there was an initial complementary distribution of calcium-binding proteins between the shell and core of the body of the developing LSO. Parvalbumin and calbindin-immunoreactive cells were present in the shell, whereas calretinin-immunoreactive cells were restricted to the core of the LSO. Gamma amino butyric acid (GABA), but not glycine, immunoreactive cells were distributed similarly in the shell of the LSO in the neonate. There were, in addition, reciprocal medial-to-lateral gradients of parvalbumin and calbindin-immunoreactive cells in the LSO shell of the neonate. These complementary patterns in the LSO were transient, however, and by the end of the second postnatal week, each calcium-binding protein differed markedly in its cellular distribution in the superior olive, including the LSO. GABA-immunoreactive cells also were restricted transiently to the shell of the LSO in neonates. The radial segregation of transient calcium-binding expression in LSO cells was orthogonal to the medial-to-lateral axis in the LSO and, therefore, parallels fibrodendritic layers and presumed isofrequency planes of the LSO. The early postnatal segregation of calcium-binding proteins in the isofrequency axis was congruent with the gradients of contralateral and ipsilateral projection cell types in adult LSO. It seems likely that developmental mechanisms regulate expression of calcium-binding protein and neurotransmitter phenotypes and that these mechanisms operate in development within the isofrequency axis as well as along the tonotopic axis of this auditory nucleus.
 ...
PMID:Calcium-binding proteins and GABA reveal spatial segregation of cell types within the developing lateral superior olivary nucleus of the ferret. 960 41

Cytosolic free calcium ion concentration ([Ca2+]cyt) after a salicylic acid (SA)-stimulus was monitored in cells of the yeast Saccharomyces cerevisiae expressing apoaequorin, which constitutes a Ca(2+)-sensitive luminescent protein, aequorin, when combined with coelenterazine. SA induced a transient [Ca2+]cyt elevation that was dependent on the concentration of SA and pH of the SA solution. The SA-induced [Ca2+]cyt elevation was not reduced in Ca(2+)-deficient medium, suggesting that Ca2+ was mobilized from an intracellular Ca2+ store(s). Benzoic acid, butyric acid and sorbic acid did not induced a [Ca2+]cyt elevation.
 ...
PMID:Salicylic acid induces a cytosolic Ca2+ elevation in yeast. 964 31

The present study was undertaken to investigate the effects of extracellular pH (pHe) and intracellular pH (pHi) on 5-hydroxytryptamine (5-HT)-induced contraction and Ca2+ mobilization in vascular smooth muscles. Strip preparations of the rabbit basilar artery without endothelium were loaded with 40 microM fura-2-AM and 2 microM BCECF-AM and mounted in an organ bath. The isometric tension was recorded by using a force displacement transducer. Administration of 5-HT caused dose-dependent contraction in the rabbit basilar arteries. Acidification of pHe from 7.40 to 6.90 reduced the 5-HT-induced contraction and [Ca2+]i transients. Alkalinization of pHe from 7.40 to 7.90, on the other hand, enhanced the contraction and elevation of [Ca2+]i. In the other series of experiments, pHi (7.12 in normal PSS) was selectively altered by adding either butyric acid or trimethylamine. Intracellular acidification (pHi = 6.89) and alkalinization (pHi = 7.35) without changes in pHe produced qualitatively similar effects to those caused by extracellular acidification and alkalinization, respectively. Ca-sensitivity, which is defined as Deltatension/Delta[Ca2+]i, was not affected by the alteration of pHe nor pHi. In the Ca2+-free solution, the addition of 5-HT produced transient increases in [Ca2+]i and isometric tension that were much smaller than those in the normal physiological salt solution. The 5-HT-induced responses of [Ca2+]i and tension in the Ca2+-free solution were not affected by acidification nor alkalinization. These results suggest that a 5-HT-induced contraction is significantly modulated by pH through changing the [Ca2+]i transients, and that the change of pHi plays, at least in part, a role in the alteration of 5-HT-induced contraction resulting from acidosis or alkalosis in the rabbit basilar artery.
 ...
PMID:Effects of pH on contraction and Ca2+ mobilization in vascular smooth muscles of the rabbit basilar artery. 1021 9

Short chain fatty acids (SCFA) are considered to be beneficial fermentation products in the gut by exerting trophic effects in non-transformed colon cells and by slowing proliferation and enhancing differentiation in colonic tumour cells. We have studied the further effects of SCFA on cellular events of early carcinogenesis, genotoxicity and cytotoxicity in rat distal colon cells. Cytotoxicity was assessed by measuring trypan blue exclusion and by determining the H2O2-induced changes in intracellular calcium concentration ([Ca2+]i) using a fluorospectrophotometer and the calcium-sensitive fluorescent dye Fura-2. The microgel electrophoresis technique (COMET assay) was used to assess oxidative DNA damage. Individual SCFA and physiological SCFA mixtures were investigated for their potential to prevent DNA and cell damage induced by H2O2. For this, freshly isolated colon cells were treated with H2O2 (100-500 microM) and 6.25 mM SCFA. We have found 100-500 microM H2O2 to cause a fast initial increase in [Ca2+]i, whereafter the levels gradually further increased. Addition of SCFA did not affect [Ca2+]i nor did it reduce the H2O2-induced increase in [Ca2+]i. Butyrate and acetate were able to reduce the induction of DNA damage by 100, 200 and 500 microM H2O2, respectively. In contrast, i-butyrate and propionate were ineffective. The degree of reduction of DNA damage for the two protective SCFA was similar. Physiological mixtures containing acetate, propionate and butyrate in ratios of 41:21:38 or 75:15:10 that are expected to arise in the colon after fermentation of resistant starches and pectin, respectively, did not show significant antigenotoxic effects. The major difference between butyrate and acetate, on one hand, and i-butyrate and propionate, on the other hand, is that the former compounds are utilized best as energy sources by the colon cells. Therefore, our results on antigenotoxicity coupled with the findings on [Ca2+]i homeostasis indicate that molecular effects on the energy system render these non-transformed, freshly isolated colon cells to be less susceptible to H2O2.
 ...
PMID:Potential of short chain fatty acids to modulate the induction of DNA damage and changes in the intracellular calcium concentration by oxidative stress in isolated rat distal colon cells. 1022 91


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>