SEARCH · PubMed Health

Results for “Calcium Compounds”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

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

At least 937 records · Page 52Linked to original sources

PubMed1995

Comparative pharmacology of calcium antagonists.

OBJECTIVE: To compare clinically relevant pharmacokinetic, pharmacodynamic and toxico logical characteristics of calcium-modulating compounds used in ischemic heart disease. DATA SOURCES: A MEDLINE search (1990 pt B to 1991 pt A revised for 1993; 1991 pt B to 1992 revised for 1993; and January to May 1993) combining the search phrases 'calcium channel blockers', 'myocardial ischemia', 'pharmacodynamics' and 'pharmacokinetics', and a search in Compact Cambridge Drug Information Source vol-6 (revised 1992, fourth quarter) using the search phrase 'calcium antagonists' and medical subject headings (MeSH) 'pharmacokinetics' and 'pharmacodynamics' were used to obtain title and abstract information on available current literature. STUDY SELECTION: Review articles, proceedings and studies published in English and available within the University of Saskatchewan library system, as they appeared to relate closely to the objective, were obtained for closer evaluation. In addition, primary references were examined, and journal reprints were selected from the authors' files. DATA EXTRACTION: The focus was on studies and objective reviews that profiled one or more representative compounds in a manner suitable for deriving background and comparative information pertaining to the objective. Data from multiple studies, or from studies that employed multiple methodological approaches, were preferentially extracted and summarized for presentation. DATA SYNTHESIS: The role of calcium in cardiac and vascular smooth muscle physiology was reviewed, highlighting the major mechanisms responsible for maintaining calcium homeostasis in these cells. With a focus on verapamil, diltiazem and 1,4-dihydropyridines currently employed in the treatment of cardiovascular disorders, a general survey of their sites of action, tissue selective pharmacodynamics, pharmacokinetic properties and side effects was undertaken in a comparative context. CONCLUSIONS: Calcium antagonists are employed in the treatment of angina, certain cardiac arrhythmias and hypertension. They are a chemically and pharmacologically heterogeneous group of compounds that act principally to inhibit the influx of calcium across certain voltage-dependent membrane channels. Concepts pertaining to calcium mobilization in the pathophysiology of myocardial ischemia, particularly at the molecular level, have evolved remarkably over the past decade. The repertoire of agents having calcium-regulating properties has expanded in parallel. The task of integrating new knowledge in both of these areas requires further attention in order to determine optimal approaches to treatment.

Animals↗

PubMed1983

Role of hexose monophosphate shunt in parathyroid hormone secretion.

The metabolism of labeled glucose by collagenase-dispersed bovine parathyroid cells was examined. When the medium calcium ion concentration was increased to 2.0 mM, the rate of 14CO2 release from [1-14C]glucose was increased 169 +/- 45% compared with the rate of 0.5 mM calcium. There was no significant change in the rate of 14CO2 release from [6-14C]glucose by this maneuver. The greatest increase in 14CO2 release and decrease in parathyroid hormone secretion occurred between medium calcium ion concentrations of 0.5-1.5 mM. This difference in the metabolism of glucose represents a true increase in hexose shunt activity because the incorporation of label from either [1-14C]- or [6-14C]glucose into parathyroid tissue lipids was equal. This suggests equilibration of label at the level of triose-phosphates. The increase in hexose shunt activity was not due to a calcium-mediated increase in glucose uptake because calcium changes did not affect 2-[3H]deoxyglucose transport by the cells. Phenazine methosulfate added to cells incubated at 0.5 mM calcium selectively increased hexose shunt activity in a dose-dependent manner (91 +/- 33% overall) and concomitantly inhibited parathyroid hormone secretion 65% overall at 0.5 mM calcium. The compound 6-aminonicotinamide inhibited hexose shunt activity but could not overcome the inhibition of hormone secretion at 2.0 mM calcium. A decrease in protein biosynthesis cannot fully explain the inhibition of hormone secretion by calcium or phenazine methosulfate because [3H]-leucine incorporation into total cell protein was not as affected as secretion.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1997

Modulation of human neutrophil function in vitro by gastrin.

We have studied the effects in vitro of gastrin-17 and gastrin-34, at concentrations from 10(-14) M to 10(-6) M, on several of the functions of peripheral blood human neutrophils, i.e. adherence to substrate, mobility (spontaneous and directed by a chemical gradient or chemotaxis), ingestion of inert particles (latex beads) and cells (Candida albicans) and superoxide anion production. Both gastrins inhibited several steps of the phagocytic process of human neutrophils, such as mobility and ingestion. By contrast, these peptides increased adherence and had no effect on superoxide anion production. In general, these effects were significant at peptide concentrations between 10(-12) M and 10(-8) M with a maximal effect at 10(-10) M. In addition, gastrin peptides induced a significant increase in intracellular cAMP levels at 30, 60 and 120 s. Moreover, the inhibitory effect of gastrin-17 on the ingestion capacity of neutrophils (latex bead phagocytosis) was similar to that obtained with EGTA, a well-known extracellular calcium chelating compound. Gastrin-17 was found to inhibit completely the stimulation of latex bead phagocytosis in neutrophils caused by the calcium ionophore A23187. These results suggest that gastrin is a negative modulator of the phagocytic process of human neutrophils, and that this effect might involve an increase in intracellular cAMP levels and a decrease in calcium entry into the cells.

Adult↗

PubMed1975

Morphological changes after simultaneous administration of isoproterenol (ISO) and K+,MG2+-Aspartate (KMg-ASP) as a physiological Ca2+ antagonist.

Calcium antagonistic compounds including physiological ions of K and Mg are supposed to protect the heart against the deleterious effect of calcium overload. Pretreatment with K,Mg-aspartate in a single i.v. dose of 100 mg/kg was performed in dogs 5--10 min prior to isoproterenol chloride injection in a single dose of 7 mg/kh s.c. Administration of K,Mg-aspartate alone in the above-mentioned dose produced reversible changes of mitochondria after 2--6 hr. K,Mg-aspartate pretreatment applied prior to isoproterenol application revealed summarization of both K,Mg-aspartate and isoproterenol-produced changes after 2--6 h without significantly preventing hypoxic-like alterations. However, the final result after 24 h was good improvement of ultrastructure generally resembling metabolic regeneration and/or enhanced metabolic activity.

Animals↗

PubMed1981

[Field study of workers with longterm exposure to calcium cyanamide (author's transl)].

"Kalkstickstoff" (calcium cyanamide) is extensively used as a fertilizer and a herbicide and also as a chemical intermediate. Its main compounds are calcium cyanamide (CaCN2) (60%) and calcium oxide (15%). In earlier times cauterized damages of the skin and the mucous membranes caused by the content of calcium oxide were common. A certain effect of CaCN2 is the reaction of intolerance after alcohol intake, which expresses as a so-called burning, a flush with redness and feeling of heat of the head, the neck and the upper part of the body often combined with tachycardia and dyspnea. Further health impairments, sometimes with fatal end, were reported repeatedly in the older literature. Convincing evidences for the causal connections between the exposure to CaCN2 and these damages are missed. They exclusively concerned farmers but not workers in the production of CaCN2. Except of the damages of the skin also diseases of the respiratory and gastrointestinal tract, the kidneys, the nervous and circulatory system as well as favoring of infectious complications and goitrogenic effects are in discussion. Furthermore it was suggested that CaCN2 causes a lack of reduced glutathione in the organism. On the occasion of establishing a preliminary MAC-value for CaCN2 in the F.R.G. an occupationally medical field study was performed on 65 workers of a calcium cyanamide factory with long-term exposure to CaCN2. The maximal CaCN2 concentration measured at the working places was 8.3 mg/m3. No signs of diseases or health impairments, which are possibly caused by CaCN2, were found with the medical examination in the above mentioned organs and organ systems. There also was no decrease of the glutathione content of the total blood detectable. With an alcohol load of 22 voluntary workers 1 till 7 hours after the working shift in 6 cases modest and in 7 cases weak flush reactions were observed. As result of the study an elevation of the MAC-value from 1 to at least 2.5 mg/m3 is proposed.

Adult↗

PubMed1990

Voltage-dependent calcium currents in trigeminal chick neurons.

The presence of action potentials, when sodium and potassium currents were blocked, has been investigated in trigeminal ganglion neurons, using the patch-clamp technique. In this conditions, inward currents, sensitive to the external application of cadmium, were detected. Activation and inactivation properties were investigated, as well as the behaviour of the current in the presence of extracellular Barium. The properties of these inward currents in trigeminal neurons are correlated to high threshold voltage-dependent calcium channels.

Action Potentials↗

PubMed1985