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PubMed2004

The influence of some aminoalkanolic xanthone derivatives on central nervous and cardiovascular systems in rodents.

A series of appropriate aminoalkanolic derivatives 2- or 4-methylxanthone was synthesized and evaluated for anticonvulsant activity in the maximal electroshock seizure (MES) and subcutaneous pentylenetetrazole seizure threshold (scPtz) assays, and for neurotoxicity (TOX). The most interesting result was the anticonvulsant activity of (R,S)-2N-(6-chloro-2-xanthonemethyl-2N-methylamino-1-propanol hydrochloride (II, which displayed anti-MES and anti-scPtz activity. Some of the obtained compounds (I - IV and V - VII) were also tested for their effect on the circulatory system (the effect on normal electrocardiogram, protection against adrenaline-, barium-, calcium- and/or strophanthine-induced arrhythmias, the effect on the arterial blood pressure and respiratory movements) and acute toxicity.

Animals↗
PubMed1987

Comparative effects of divalent cations on the methylmercury-induced alterations of acetylcholine release.

Bath application of methylmercury (MeHg) at the murine neuromuscular junction blocks synchronous evoked release of acetylcholine (ACh) and then increases spontaneous release of ACh effects observed electrophysiologically as cessation of EPPS, and increased MEPP frequency (MEPPf), respectively. The objectives of the present study were to test whether the effect of MeHg on spontaneous release was Ca++-specific by substituting Sr++ or Ba++ for Ca++, whether the time course of MeHg-induced block of synchronous evoked release was altered by varying Ca++ concentrations or substituting Sr++ and whether the processes involved in the decay of elevated MEPPf after repetitive stimulation (asynchronous evoked release) were altered by MeHg. MEPPf was recorded continuously from the rat hemidiaphragm using conventional methods during pretreatment with 2 mM Ca++, 2 mM Sr++ or 0.5 mM Ba++ and subsequently with the cation plus 100 microM MeHg. The time to peak MEPPf in MeHg was not different under any condition; however, peak MEPPf was lower in Sr++ solutions than in Ca++ or Ba++ solutions. EPPs were recorded from the rat hemidiaphragm cut muscle preparation during pretreatment with either 2, 4 or 8 mM Ca++ or 2 or 4 mM Sr++ and subsequently with the cation plus 100 microM MeHg. The latency to block of the EPP in 4 and 8 mM Ca++ was not significantly different from the latency in 2 mM Ca++. The latency to block in 2 or 4 mM Sr++ was also not different from that in Ca++. In addition, under all conditions EPP amplitude remained virtually unchanged from pretreatment values until block occurred after 8 to 9 min exposure to MeHg.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1979

Intracranial vasospasm: a study with iron compounds.

The effects of topically applied hemoglobin, methemoglobin, hemin, ferrous chloride (FeCl2) and ferric chloride (FeCl3) were investigated by observation through the operating microscope to determine their effect on the normal and spastic canine basilar artery. Following transclival exposure, the artery was made spastic by puncture or topical barium chloride. No consistent changes in arterial diameter were seen with topical hemoglobin, methemoglobin, or hemin. The buffered ferrous ion (Fe++) caused marked vasodilation at concentrations of 10 microgram/ml. The buffered ferric ion (Fe++) caused mild vasoconstriction at similar concentrations. The possible role of iron (a component of hemoglobin) in vasospasm following subarachnoid hemorrhage and subsequent hemoglobin degradation is discussed.

Animals↗
PubMed2000

Ba(2+)-induced chromaffin cell death: cytoprotection by Ca(2+) channel antagonists.

Exposure of bovine adrenal medullary chromaffin cells to Ba(2+) ions (in the absence of Ca(2+) ions) caused their death, measured as lactate dehydrogenase (LDH) release. The concentration of Ba(2+) required to damage the cells by about 65% ranged between 1 and 10 mM (no Ca(2+) added); the required exposure time was rather brief (15 min-4 h). The simultaneous presence of Ca(2+), Mg(2+) or Zn(2+) together with Ba(2+) (2 mM, 4 h) afforded cyprotection (60-80%). Individual selective blockers of Ca(2+) channel subtypes afforded no protection. However, combined nifedipine (3 microM) plus omega-conotoxin MVIIC (3 microM) offered full protection. Substantial protection was also seen with the "wide-spectrum" Ca(2+) channel blockers penfluridol (0.3 microM), lubeluzole (3 microM), dotarizine (3 microM), flunarizine (3 microM), and mibefradil (3 microM). This protection was due to blockade of Ba(2+) entry through Ca(2+) channels because dotarizine (10 microM) inhibited the increase in cytosolic [Ba(2+)] seen in fura-2-loaded chromaffin cells. Once Ba(2+) accumulated in the cytosol, it was not extruded by the Na(+)/Ca(2+) exchanger, as shown by the prolonged and sustained elevation of the fura-2 signal. This contrasts with the fast dissipation of the fura-2 signal generated by [Ca(2+)](i) elevation. Thus, Ba(2+) overload can cause cell death by mechanisms similar to those reported for Ca(2+) overload and might be used as a novel and convenient tool to search for new cytoprotective compounds.

Animals↗
PubMed1984

[Compound technic: the effect on lateral resolution, acoustic shadowing and the detection threshold of calculi].

The examination under discussion shows the specialities of the compound technique, by example of the octoson machine. When the number of transducers is increased, i.e. as by compound technique, an improvement in the lateral resolution can be recognized. The transducers lying outside the C-curve of the octoson demonstrate the structure very nearly axial. The shadowing of concrements (which is very important for recognition) is only evident when using 1-2 transducers and disappear in the compound technique. By increasing the number of transducers, shadowing behind air and bariumsulphate disappears.

Air↗
PubMed1979

Comparative uptake of fluoride from sodium fluoride, ammonium fluoride, and barium fluoride in rat teeth when predominantly administered in the pre-eruptive stage of development.

A comparative study was undertaken which focused on the systemic uptake of sodium fluoride (NaF), ammonium fluoride (NH4F), and barium fluoride (BaF2) in rat pups. Two critical achievements made this comparative study possible: (a) the demonstration of significant increases in fluoride (F) uptake-deposition in the treatment group pups relative to control group rats as a result of stomach tube feeding; and (b) the demonstration of clear-cut differences in F concentration levels between the treatment groups as a result of this stomach tube-systemic uptake. Data were reliable and significant enough to suggest that, of the 3 compounds in question, NH4F is absorbed most successfully in a systemic fashion, whereas BaF2 is the least absorbed.

Ammonia↗
PubMed1989

Histopathologic findings and energy dispersive X-ray spectroscopic analysis of experimentally induced foreign-body pneumonias in rats.

To document the diagnostic features of foreign-body pneumonias, four commonly used orally administered medicaments were instilled into the lungs of Sprague-Dawley rats. Rats in each group received a single 0.4 ml dose of either barium sulfate suspension (BaSO4), mineral oil, Pepto-bismol, or Kaopectate inoculated into a lung via a mainstem bronchus. The other lung served as a non-inoculated control. Rats were euthanatized on post-inoculation day 2 or 7 in order to document fully-developed acute pulmonary lesions and developing, chronic pulmonary lesions, respectively. Light microscopic features of BaSO4-inoculated lungs were distinctive from changes in mineral oil-inoculated lungs at both post-inoculation days. On post-inoculation day 2, rats inoculated with BaSO4 had pneumonia characterized by large numbers of alveolar macrophages containing green-to-brown granular material. There was minimal interstitial involvement. On post-inoculation day 2, mineral oil caused pneumonia characterized by giant cells and alveolar macrophages that had cytoplasms distended with variably-sized clear vacuoles. Lungs inoculated with BaSO4 or mineral oil had changed little on post-inoculation day 7 compared to the light microscopic features observed on day 2. On post-inoculation day 2, rats inoculated with either Pepto-bismol or Kaopectate had broncho-interstitial pneumonia with areas of necrosis and hemorrhage. On post-inoculation day 7, lungs inoculated with Pepto-bismol or Kaopectate had extensive fibrosis within alveolar lumens. Energy dispersive spectroscopy performed on sections of lung from rats given BaSO4, Pepto-bismol, and Kaopectate yielded a unique elemental spectrum for each compound in situ on post-inoculation days 2 and 7.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Accessory bile duct draining into the stomach: case report and review.

Accessory bile duct with ectopic drainage into the gastrointestinal tract is an extremely rare congenital anomaly, and only 55 cases have been reported in the literature. We present another case of accessory bile duct draining into the stomach. Barium meal study of the stomach first revealed the accessory bile duct, and the diagnosis was confirmed by gastrofiberscopy, ultrasonography, hepatobiliary scintigraphy, computed tomography (CT), and endoscopic retrograde cholangiopancreatography (ERCP).

Adult↗
PubMed1988

The membrane potential modulates the ATP-dependent Ca2+ pump of cardiac sarcolemma.

The effect of membrane potential on the activity of the ATP-dependent Ca2+ pump of isolated canine ventricular sarcolemmal vesicles was investigated. The membrane potential was controlled by the intravesicular and extravesicular concentration of K+, and the initial rates of Ca2+ uptake both in the presence and the absence of valinomycin were determined. The rate of Ca2+ uptake was stimulated by a inside-negative potential induced in the presence of valinomycin. The valinomycin-dependent stimulation was enhanced by the addition of K+ channel blocker, tetraethylammonium ion or Ba2+. The electrogenicity of cardiac sarcolemmal ATP-dependent Ca2+ pump is suggested from the increase of Ca2+ uptake by negative potential induced by valinomycin.

Adenosine Triphosphate↗
PubMed1984

Combinations of laxatives for bowel preparation: are they necessary?

To determine whether combinations of saline and surface-acting laxatives have any superior action over saline laxatives alone in cleansing the colon, patients having double-contrast barium enema examinations were randomly allocated to magnesium citrate alone and magnesium citrate with either oral or rectal bisacodyl. The addition of bisacodyl conferred no benefit over magnesium citrate alone. A companion study of magnesium citrate and sodium picosulphate (Picolax) showed no benefit over magnesium citrate alone. It is concluded that it is unnecessary to add a contact or surface-acting laxative to 25 g of magnesium citrate for bowel preparation.

Administration, Oral↗
PubMed1988

Barium enemas are a headache.

The frequency of headache after Picolax (sodium picosulphate, Nordic Ltd) preparation for barium enema was investigated and its association with dehydration, as assessed by haemoconcentration, was determined. Eleven out of 41 patients (26.8%) complained specifically of headaches. Although patients with and without headaches developed significant increases in haemoglobin concentration after Picolax preparation, the rise in haemoglobin in those with headaches was significantly greater than in those without (P less than 0.05). In both groups the haemoglobin concentration returned to normal after a bowel washout. These results suggest an association between dehydration and headache developing after a Picolax regimen. It may be possible to prevent this symptom by advising on the intake of specific volumes of fluid during preparation for barium enema.

Adult↗
PubMed1999

Capillary zone electrophoresis of potassium in human vitreous humour: validation of a new method.

The analysis of potassium in the vitreous humour has long been regarded as an important tool in medicolegal and forensic toxicological investigation, particularly for the determination of the post-mortem interval. The present work was aimed at the optimisation and validation of a reliable, simple and fast capillary electrophoresis method for potassium analysis in the human vitreous humour with indirect UV detection at a wavelength of 214 nm. Electrophoretic separations were carried out in a running buffer comprising 5 mM imidazole, 5 mM 18-crown-6 ether and 6 mM D,L alpha-hydroxybutyric acid (HIBA), adjusted to pH 4.5. Constant voltage runs were carried out by applying a voltage of 500 V/cm at 25 degrees C. The samples were injected in the hydrodynamic mode at the anodic end of the capillary (0.5 p.s.i. for 10 s; 1 p.s.i. = 6894.76 Pa). The method showed good linearity in the concentration range from 6.5 mM to 16.25 microM, with an r2 value of 0.9994. The limit of detection, based on a signal-to-noise ratio of three, was 9.0 microM. Absolute intra-day RSDs of migration times were <0.40%, while the day-to-day values were < or =1.72%. Absolute peak area reproducibility was always better than 2.50%. A comparison of capillary electrophoresis with flame photometry on twelve real autopsy samples showed an excellent correlation with an r2 value of 0.9333. A preliminary application to real cases (20 subjects) was carried out plotting vitreous humour potassium vs. post-mortem interval with a resulting r2 of 0.904 and a Y-intercept of 4.75 mM, in agreement with the existing literature.

Aqueous Humor↗
PubMed1993

Divalent cation-induced lipid mixing between phosphatidylserine liposomes studied by stopped-flow fluorescence measurements: effects of temperature, comparison of barium and calcium, and perturbation by DPX.

To understand the mechanism of membrane fusion, it is important to study the processes that mix the lipids of two apposed membranes. We measured the rates of divalent cation-induced aggregation and lipid mixing of bovine brain phosphatidylserine (BBPS) LUV, using light scattering and a resonance energy transfer assay. The lipid and divalent cation solutions were combined by stopped-flow mixing, which permitted measuring the half-times of aggregation and lipid mixing between pairs of liposomes. The collisional quencher DPX [p-xylene-bis(pyridinium bromide)], used in a liposome contents-mixing assay, lowered the main transition temperature (Tm) of BBPS by about 10 degrees C and decreased the temperature threshold for lipid mixing. Since DPX was inside the liposomes for the latter measurements, this implies that perturbations to the inner monolayer affect the reactivity of the liposome. When palmitoyl-oleoyl-PS (POPS) was substituted for BBPS, little or no lipid mixing occurred. Ca(2+)- and Ba(2+)-induced BBPS aggregation and lipid mixing were compared as a function of temperature and divalent cation concentration. Aggregation rates were nearly insensitive to temperature and correlated with the percent of PS bound to either Ba2+ or Ca2+. Above Tm, lipid-mixing rates increased with the Ba2+ and Ca2+ concentrations and temperature, even above the Tm of the Ba2+/PS complex. Arrhenius plots were linear for both ions. The temperature dependence was greater for Ca(2+)- than Ba(2+)-induced reactions, and the slopes were independent of divalent cation concentration. When equivalent fractions of PS were bound with divalent cation at, and above, 20 degrees C, the lipid-mixing rate was greater with Ca2+ than with Ba2+. The faster rate may reflect greater activation entropies and/or greater attempt frequencies at one or more steps in the Ca(2+)-induced process. We conclude that stopped-flow mixing permits better characterization of initial interaction between liposomes, that small changes in the acyl chain region of the PS bilayer or the inner monolayer can have large effects on lipid-mixing rates, and that the differences between Ba(2+)- and Ca(2+)-induced interactions may be related to qualitative differences in the destabilization step.

Animals↗