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Biomedical subjects

J Durlach

Publications and source records attributed to J Durlach.

At least 91 records · Page 5Linked to original sources
PubMed1988

Study of the antagonism between zinc and various embryonic toxics on human amnion permeability. I. Zinc and cadmium.

The effects of Cd and Zn have been studied on the ionic permeation of the isolated human amnion, expressed by the measure of the transamniotic conductance Gt and the flux ratio (mother-fetus/fetus-mother: F1/F2). Cd has no action on Gt on the fetal side and decreases Gt on the maternal side by a screening effect. Zn acts on the two faces by a screening-binding effect. The ratio F1/F2 remains constant with Zn concentration, but decreases with Cd and becomes less than 1 at 5 mmol/l of Cd. F1/F2 decreases with the duration of the administration of Cd. Zn has the opposite effect of Cd on the ionic transfer and has a stabilizing action on the amnion. Moreover, Zn may antagonize the noxious effect of Cd on the maternal side.

Amnion↗
PubMed1988

Magnesium research: a brief historical account.

The early historical period, from the 18th century to the first quarter of our century, is mainly that of the development of chemical and pharmacological knowledge. The modern period began in 1926 when the essential character of magnesium was acknowledged. The early part of the modern period, up to the 60s, saw the foundation of our knowledge of the basic physiological, epidemiological and clinical aspects. The present modern period began in 1971 with the First International Symposium on magnesium and the creation of SDRM (the International Society for the Development of Research on Magnesium), an international coordinating structure, which holds its Fifth International Symposium in August 1988 in Kyoto. The subjects of the 20 sessions show that today's magnesium research while remaining active in the basic sciences also embraces all the facets of pathology.

Animals↗
PubMed1988

Modification of human amniotic membrane stability after addition of magnesium salts.

Membrane stability is determined by the measure of two electrical parameters: the total ionic conductance (Gt) and the ionic fluxes (F1, F2). These two categories of interaction between the membrane polar groups and magnesium explain its effects on membrane stability. The screening interaction is characterized by the fact that the polar groups are masked by magnesium and by a decrease of Gt, F1 and F2. The membrane stability increases. The binding interaction is characterized by the fact that the polar groups are accessible to other ions and by an increase of Gt, F1 and F2. The membrane stability decreases. Among the different magnesium salts studied, MgCl2, Mg acetate and Mg citrate increase then decrease the stability on the two faces of the amnion. MgSO4, Mg lactate and Mg nitrate increase the stability on the maternal side, but decrease it on the fetal side. MgCl2, Mg acetate and Mg citrate have an identical effect on the two faces of the amnion which does not influence the transfer ratio.

Amnion↗
PubMed1988

Analysis of magnesium membraneous effects: binding and screening.

There are two categories of electrostatic interactions between cations and negatively membrane charged surfaces. First, there is the usual type of electrostatic binding where the cations complex to anionic surface moieties. There exists, however, a second type of association, often referred to as screening. In this case, the cations remain mobile, being held loosely in a diffuse layer close to the surface. When divalent cations are added in the bathing medium, a screening effect (S) induces a reduction of Gt, a binding effect (B) induces an increase of Gt and a screening-binding effect (S-B) induces a reduction, then an increase, of Gt. In the isolated human amnion, among the magnesium salts studied, only MgCl2, Mg citrate and Mg acetate have a S-B effect on both faces of the membrane.

Amnion↗
PubMed1988

Relationship between magnesium, carcinogenic metals and ionic permeability of the human amnion.

The effects of the well established carcinogenic metals or metalloids (As, Be, Cr, Ni), hypothetically carcinogenic but well-established cocarcinogenic metals (Cd, Pb, Co) and weak co-carcinogenic metals (Al, Cu, Fe, Zn) and the antagonism between Mg and these metals were studied on the ionic transfer through the isolated human amnion. The ionic transfer is estimated by the measure of the membrane potential (delta psi), the cationic number transference t+ and the ionic fluxes (F1, F2). All carcinogenic metals increase delta psi (+) and reduce t+, F1 and F2. Mg has an opposite action with regard to Cd, Pb and Ni, but may act as a co-carcinogenic agent by increasing the effects of Al, Cu and Zn.

Aluminum↗
PubMed1988

Similar antagonistic effects of Ca N-acetylhomotaurinate on depression of motor activity and lethality induced by acetaldehyde or ethanol.

Among several taurine derivatives, Ca N-acetylhomotaurinate (Ca AOTA) appears to be the most active anti-acetaldehyde and anti-alcohol agent. Studies of the antagonism of the hypomotility induced by high intravenous doses of acetaldehyde or ethanol in mice and of the lethality of high intragastric doses of acetaldehyde in rats show its superiority which appears logical after systematic studies of these derivatives and their components. The reinforcing action of the nervous activity due to N-acetylation of these sulfonic aminoacids differs according to the target. Since Ca AOTA is the most active against acetaldehyde and ethanol toxicity, this central nervous action first relies on its effects on neuromodulators, neuromediators and cations primarily involved in the mechanisms of alcohol dependence through its taurine (TA) structure, its gamma-aminobutyric acid (GABA) agonist actions, its anti-opioid receptor "naloxone-like" effects and its possible activity as a subcellular Ca carrier. Ca AOTA may also intervene through its high membrane stabilizing effect. Compared with the other compounds, it appears to be the most active both in vitro on the erythrocyte membrane of the rabbit and on the human amnion membrane and ex vivo on the alcoholic rat's erythrocyte membrane. Among several taurine derivatives similarly efficient in toxicity of both acetaldehyde and ethanol, Ca AOTA is the best. Its efficiency against the most toxic metabolite of ethanol may specifically rely on Ca and TA dependence of acetaldehyde-dehydrogenase or on an aspecific mechanism such as the role of free radical scavenger due to its taurine structure. Ca AOTA appears to be a promising drug against alcoholism because of its effects on the multiple targets involved in the mechanism of alcohol dependence. A large multicentric coordinated trial has effectively confirmed the reliability of these pharmacological speculations.

Acamprosate↗
PubMed1985

Comparative study of the effects of two tocolytic agents (magnesium sulfate and alcohol) on the ionic transfer through the isolated human amnion.

The effects of two tocolytic agents (MgSO4 and ethanol) on ionic transfer through the isolated human amnion were observed and compared. The ionic transfer was estimated by conductance and ionic flux measurements. MgSO4 increased the ionic conductance (Gt) on the fetal side; it also increased the ionic fluxes from fetus to mother and from mother to fetus, but it decreased the flux ratio. Ethanol decreased Gt in both directions as well as the ionic fluxes; the flux ratio, however, remained constant. Thus, the two tocolytic agents (MgSO4 and ethanol) show a negative effect on ionic transfer through the human amnion.

Amnion↗
PubMed1985

Influence of magnesium deficiency on liver collagen after carbon tetrachloride or ethanol administration to rats.

The effects of magnesium deficiency on liver collagen after the administration of a hepatotoxic substance were investigated. Rats, fed a control or magnesium-deficient diet (0.040 g/kg), received six CCl4 or mineral oil injections administered at 2-d intervals starting from the first day of diet treatment. They were killed 3 or 12 d after the last injection. Between postinjection d 3 and 12, no change of magnesium concentration in liver was observed in the deficient rats. Three days after the end of treatment liver calcium in the magnesium-deficient CCl4-treated rats was higher than in any other group. Liver collagen of untreated control rats and untreated magnesium-deficient rats was not significantly different. In control and magnesium-deficient animals receiving CCl4 treatment, the liver collagen levels were significantly higher than in untreated rats. The magnesium-deficient rats receiving CCl4 have higher liver collagen than the controls receiving CCl4. In a second experiment the effect of suboptimum intake of magnesium (0.120 g/kg) combined with the ingestion of ethanol was studied in rats given a solution of ethanol in water for 55 d as their only source of fluid. Mortality occurred in the magnesium-deficient rats receiving ethanol, and body weights of these rats were lower than those of animals in the other three groups. The collagen concentration in liver was higher in magnesium-deficient rats consuming ethanol than in any other group. The synergistic action between magnesium deficiency and ethanol therefore appears to be analogous to that observed with CCl4.

Animals↗
PubMed1985

[Comparison of the effects of taurine and magnesium on electrical characteristics of artificial and natural membranes. IV. Effects on different components of the paracellular and cellular conductances of the human amnion].

The ionic conductance, Gt, through the isolated human amnion is the sum of several conductances: Gt = Gp + Gc + Gs. Gp, the paracellular conductance is: Gp = Gj + Gjc (Gj is due to the intercellular channel and Gjc due to the electrical coupling factor); Gc, the cellular conductance is: Gc = Gc1. Gc2/Gc1 + Gc2 with Gc1 = GAC + GAC1 and Gc2 = GM + GM1, GAC and GM being the dependent conductances on amniotic cavity (AC) and maternal (M) sides; GAC1 and GM1 being the leak conductances on AC and M. Gp and Gc are due to epithelial cell layer and Gs (conductance in a series) is due to the other layers. The utilization of metabolic inhibitors (ouabain, amiloride, DNP) allows one to split up Gt into various components. In this study, the action of magnesium and taurine (TA) was studied on the various conductances in Hanks' solution modified by metabolic inhibitors. In Hanks' solution: + ouabain, Mg and TA increased GAC1 and GM1; - + amiloride, Mg increased GAC and GM but TA had no effect; - + ouabain + amiloride, Mg and TA increased GK. In this way, Mg appears to have an action on the ATPase and on the regulation of the Na+ and K+ channels, but TA has no effect on the ATPase but TA appears to govern the viability of the Na+ and K+ channels. Moreover, TA and Mg have a compensatory effect on GAC1, GM1 and Gjc in Hanks' solution, but their actions are not cumulative.

Adenosine Triphosphatases↗
PubMed1985

[Comparison of the effects of taurine and magnesium on electrical characteristics of artificial and natural membranes. V. Study on the human amnion of the antagonism between magnesium, taurine and polluting metals].

The effects of metal pollutants (Pb, Cd, Hg, As) were studied on strips of human amnion isolated from the placental zone put in between two Ussing chambers with Hanks' solution at 37 degrees C and pH 7.4. The total conductance Gt through the human isolated amnion was decreased on the fetal side by Pb and As; on the maternal side by Cd, Hg and As. When Gt was decreased by metal pollutants, Mg or taurine (TA) were added in the external medium to induce an antagonism between Mg or TA and metal pollutants. The addition of Mg increased significantly the Gt reduced by Pb, Cd and Hg, but had no effect on the Gt reduced by As. The addition of taurine increased significantly the Gt reduced by Cd and Hg, but had no effect on the Gt reduced by Pb and As. Dixon's kinetics (Gt as a function of the Mg or TA concentration when the metal pollutant concentration increased) indicate that there is a competitive inhibition between Mg-Pb and Mg-Cd (the inhibition constant Ki is lower with Pb (= 2.5) than with Cd (= 11.4) and suggests a greater antagonism between Mg-Pb than between Mg-Cd). Moreover, there appears to be a noncompetitive inhibition between Mg-Hg, TA-Cd and TA-Hg. These results indicate that Mg and TA, on the fetal side, exert an action on the same sites and that, on the maternal side, their action takes place on the same sites and also on different ones. Also, TA can be considered as a partial magnesium agonist, at least in the human amnion.

Air Pollutants↗
PubMed1985

Monovalent cations transfer through isolated human amnion: a new pharmacological model.

Transfer of monovalent cation through the isolated human amnion consists of different factors: paracellular, coupling, ATPase dependent cellular transfer, leak cellular transfer. Understanding this transfer permits testing of the action of various substances. Physiological substances (Mg, taurine) increase ionic transfer and there is a vicarious effect between Mg and taurine. The tocolytic agents MgSO4 and ethanol do not exhibit a good effect on the transfer: decrease with ethanol; equality between entry and exit fluxes with MgSO4. On the other hand, amphotericin B increases mother-to-fetus transfer. Polluting metals (Pb, Cd, Hg, As) dramatically reduce exchanges and almost completely inhibit amnion permeability. Ingestion of ethanol also exhibits a dramatic effect on the exchange between mother and fetus through the amnion. Study of ionic transfer in vitro can be considered a pharmacological model to investigate the modifications of mother-fetus exchanges by various substances.

Amnion↗
PubMed1985

Magnesium level in drinking water and cardiovascular risk factor: a hypothesis.

Water hardness can no longer be considered as the most reliable "water factor' with regard to the cardiovascular risk observed in epidemiologic studies. Only two out of three studies have shown a reverse correlation between cardiovascular mortality and water hardness. But studies carried out on the water Mg level alone, as opposed to those on water hardness (Ca + Mg) have all shown a reverse correlation between cardiovascular mortality and the Mg level. In developed countries, the Mg intake is often marginal and the Mg intake coming from drinking water represents the critical factor through which the Mg intake is deficient or satisfactory. Thus, Mg deficiency, either experimental or in man facilitates cardiovascular pathology. The importance of the Mg intake in drinking water is both quantitative and qualitative. Water containing Mg is better and more quickly absorbed than dietary Mg. This particular availability might help to understand why an adequate water Mg level may determine a better state of health, even without any Mg deficiency. Epidemiological data in man and experimental data in rats have demonstrated that the intake of water containing a sufficient amount of Mg may prevent arterial hypertension and correlated ionic and nervous disturbances. Indirectly the water Mg level also interferes in the leakage of food-borne Mg during cooking. There is an inverse correlation between the Mg loss in the cooked food and the Mg level of the cooking water itself. Mg appears to be an antagonist of noxious polluting agents (e.g. in the human amnion, Mg is a competitive inhibitor of Pb and Cd). It is not advisable to enrich water in Mg in the course of the processing since its corrosivity index would also increase. The best pathway is probably to neutralize corrosive water by filtration on calibrated grains of earth-alkaline metals (Neutralite or Magno or Akdolit) to ensure the highest possible Mg/Ca ratio, with the best anticorrosive power.

Animals↗
PubMed1984

A homotaurine derivative reduces the voluntary intake of ethanol by rats: are cerebral GABA receptors involved?

The effects of some derivatives of homotaurine (3 APS), the well known GABA agonist, were tested on the voluntary intake of ethanol by rats. Spontaneously ethanol drinking rats (DR) were selected and had a constant voluntary intake of ethanol by rats. Spontaneously ethanol drinking rats (DR) were selected and had a constant voluntary intake of a 12% ethanol solution (VIE) during 14 days (about 5 g/kg body weight daily). Calcium acetylhomotaurine (0.26 and 0.52 mmol/kg daily IP) significantly reduced VIE and this was inhibited by the GABA antagonist bicuculline (2 mg/kg IP). The conditioned aversion test to saccharin was negative. Bicuculline alone did not affect VIE. Other homotaurine (3-APS) derivatives: sodium acetyl homotaurine (Na AOTA), homotaurine (OTA), sodium acetyltaurine (Na A TA) and calcium chloride (CaCl2) did not affect VIE. These data suggest that the gabaergic system could be implicated in VIE. MERAM Lab. patent.

Acamprosate↗
PubMed1984

Vigilance states and cerebral monoamine metabolism in experimental magnesium deficiency.

Correlations between cerebral monoamine metabolism and electrophysiological parameters were compared in 18 male Wistar rats subjected to a magnesium-restricted diet and in 14 normal rats. During the 40-day experimental period, plasma and erythrocyte Mg2+ levels and plasma Ca2+ and phosphorus levels were measured, and electroencephalographic tracings as well as clinical data were recorded at regular intervals. At the end of the study, the animals were killed and cerebral concentrations of monoamines and their metabolites were determined. Cerebral monoamine disorders characterized by a rise of dopamine and 5-hydroxyindole-3-acetic acid levels were observed in the magnesium-deficient group. This rise was accompanied by an increase in wakefulness and a decrease in sleep percent. The role played by magnesium in cerebral monoamine metabolism and sleep cycles is discussed.

3,4-Dihydroxyphenylacetic Acid↗