bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrokinetic properties of endotoxins and their significance for the limulus amoebocyte lysate test
Authors: Baggerman C , Bonekamp B C , Kannegieter E M , Loos J A , Junginger H E 
Published: April 2011

Abstract
The electrokinetic properties of the endotoxins of Escherichia coli and Serratia marcescens have been examined. Both endotoxins are negatively charged, with the zetapotential being increased by the presence of cations whose relative influence resembles the Schulze-Hardy rule for colloid stability. Fe3+ and Th4+ ions are capable of reversing the negative charge of the endotoxin particles to positive. These cations were found to have a strong inhibitory effect on the activity of endotoxins in the limulus amoebocyte lysate test but the inhibitory effect did not parallel changes in the zetapotential because the effect occurred at concentrations too low to affect this parameter.
Evaluation of the percutaneous absorption and metabolism of some aminopropiophenones
Authors: Markantonis S L , Kyroudis A , Beckett A H 
Published: April 2011

Abstract
The absorption of diethylpropion (DEP I), dimethylpropion (DMP I) and some of their basic metabolites into and passage through the skin was investigated and a comparison of their metabolism following oral and percutaneous administration made. High percentages (60–80%) of DEP I and its metabolites and a small percentage of DMP I and its metabolites were taken up into the skin in less than 2 min—the remaining percentages of the compounds were absorbed into the skin by a first order process. The rate of appearance of the compounds in the blood, which reflects their rate of passage through the skin, did not correlate with their rate of absorption into the skin. More metabolism occurred with all the compounds after their oral administration than after their percutaneous application.
Locomotion and stereotyped behaviours induced by 1-amino-3,5-dimethyladamantane (D 145) and apomorphine in the rat: a comparison
Authors: Ljungberg Thomas 
Published: April 2011

Abstract
The locomotion and stereotyped behaviours induced by the two dopamine agonists, 1-amino-3,5-dimethyladamantane (D 145) and apomorphine in rats have been investigated using a holeboard apparatus. Unlike apomorphine, D 145 did not induce compulsive gnawing, but it did induce locomotion dose-dependently. However, the pattern of locomotion was different from that induced by apomorphine and the locomotion itself was potently antagonized by haloperidol but not by sulpiride; this is the opposite to apomorphine-induced locomotion. This indicates that locomotion induced by dopamine agonists is not a unitary phenomenon but that different ‘types’ of locomotion, with different pharmacological properties, can be induced. Low doses of D 145, given before apomorphine, reduced apomorphine-induced gnawing and enhanced apomorphine-induced locomotion. The long lasting ‘priming’ effect known to occur after repetitive injections of apomorphine was not mimicked by D 145. Apomorphine and D 145 are considered to be two specific DA agonists; their behavioural-pharmacological profiles, however, are quite different.
Localized cracking around pigment particles in tablet film coatings: a theoretical approach
Authors: Rowe R C 
Published: April 2011

Abstract
The problem of localized cracking around pigment particles in tablet film coatings has been treated as being analogous to stress cracking in two phase ceramics. For this purpose a simple model of a spherical cavity in an infinite isotropic medium has been used. As well as allowing the estimation of the stresses generated by the differences in thermal expansion of the dispersed pigment and the polymer matrix, the model predicts the effect of some formulation variables. The predictions are in agreement with the observed cracking on film-coated tablets.
The influence of chronic or acute nicotine pretreatment on ethanol-induced gastric ulceration in the rat
Authors: Wong S H , Ogle C W , Cho C H 
Published: April 2011

Abstract
The effects in rats of chronic or acute nicotine pretreatment were studied on three gastric parameters: ethanol-induced ulceration, gastric wall mucus content and gastric acid secretion, under basal or histamine-stimulated conditions. Oral administration of ethanol (40%, 10 ml kg−1) depleted gastric wall mucus and produced ulceration in the gastric glandular mucosa. Ten-day nicotine pretreatment (15 or 25 μg ml−1 drinking water) worsened the adverse effects of ethanol on mucosal ulceration and mucus content, potentiated the gastric secretory action of histamine, but did not affect basal acid secretion. Single oral doses of nicotine (2 or 4 mg kg−1, given 1 h beforehand) prevented ulceration and mucus depletion in ethanol-treated animals; however, they did not influence either basal or histamine-stimulated gastric acid output. It is concluded that chronic nicotine administration aggravates ethanol ulceration, possibly by decreasing gastric wall mucus content and sensitizing the stomach to the acid secretory action of histamine. On the other hand, an acute oral dose of nicotine preserves the mucus content and prevents ethanol-induced ulcer formation.
Effects of chloroquine and didesethylchloroquine on rabbit myocardium and mitochondria
Authors: Essien E E , Ette E I 
Published: April 2011

Abstract
The effects of chloroquine and didesethylchloroquine on the rabbit isolated perfused heart and on calcium binding and accumulating ability of the heart mitochondria were investigated. The drugs produced negative chronotropy, negative inotropy and a decrease in coronary flow rate in the isolated perfused myocardium. Both chloroquine and didesethylchloroquine significantly decreased mitochondrial calcium binding and accumulation. These results suggest that the cardiodepressant actions of chloroquine could be due in part to alterations in the calcium accumulating abilities of the mitochondrial membranes, and that didesethylchloroquine, among other metabolites, does contribute significantly to the total observed effect of chloroquine on the cardiovascular system.
The ability of amine N-methyltransferases from rabbit liver to N-methylate azaheterocycles
Authors: Damani L A , Shaker M S , Godin C S , Crooks P A , Ansher S S , Jakoby W B 
Published: April 2011

Abstract
The substrate specificity of two homogeneous amine N-methyltransferases from rabbit liver has been demonstrated to extend to the azaheterocycles pyridine, R-(+)-nicotine and S-(−)-nicotine. Both enzymes methylate R-(+)-nicotine at the pyridyl nitrogen to afford the N-methylnicotinium salt, whereas S-(−)-nicotine does not act as a substrate for either enzyme. Surprisingly, R-(+)-nicotine is methylated at either the pyridyl nitrogen, or the pyrrolidine nitrogen, to afford the two isomeric monomethylate nicotinium ions when an enzymic preparation containing both methyl transferase activities was used. Under similar conditions S-(−)-nicotine was methylated only at the pyridyl nitrogen. The production of charged metabolites in-vivo, from the large number of pyridine-compounds that are used as drugs, or are present in the environment, may be of toxicological significance, in view of the reported toxicities of several such quaternary ammonium compounds.
A thermodynamic analysis of the Collander equation and establishment of a reference solvent for use in drug partitioning studies
Authors: Beezer Anthony E , Gooch Carolyn A , Hunter William H , Volpe Pedro L O 
Published: April 2011

Abstract
A thermodynamic analysis of the Collander equation, In PI = a + b In PII (I and II refer to two different partitioning systems with partition coefficients PI and PII, respectively), is given and applied to three forms of correlation. The intercept, a, is shown to have no general fundamental significance whereas the slope, b is shown to reflect differences in non-aqueous solvent properties; b is also shown to be of use in scaling solvent behaviour to select solvents which closely represent biological membrane properties for use in partitioning studies. Laboratory and literature data are subjected to the analysis.
Crystallographic, theoretical and molecular modelling studies on the conformations of the salicylamide, raclopride, a selective dopamine-D2 antagonist
Authors: Högberg Thomas , Norinder Ulf , Rämsby Sten , Stensland Birgitta 
Published: April 2011

Abstract
The structure of the potent dopamine-D2 antagonist, raclopride, (S)-3,5-dichloro-N-[(1-ethyl-2-pyrrolidinyl)methyl]-6-methoxysalicylamide (+)-tartrate, has been determined by X-ray crystallography. The benzamide moiety of raclopride is planar in accordance with other salicylamides (FLA 797 and eticlopride). The planar conformation is stabilized by two intramolecular hydrogen bonds, i.e. one between the amide hydrogen and the methoxy group and one between the phenol hydrogen and the carbonyl group. The side-chain of raclopride has an extended conformation in contrast to the solid state conformations of FLA 797 and eticlopride. The side-chain conformations were studied by rigid rotations followed by MM2PI relaxations of the eight local minima found. Small energy differences (&lt;4&#x006d;̇0 kcal mol−1) exist between the various extended and folded conformations. Based on modelling studies with piquindone as template, it is suggested that the salicylamides with N-ethyl-2-pyrrolidinylmethyl side-chains interact with the dopamine-D2 receptor in a folded or a half-folded conformation.
Transmitter releasing action of selegiline ((—)-deprenyl) from peripheral sympathetic nerves under different experimental conditions
Authors: Török Tamás L , Pauló Tünde , Tóth Péter T , Nguyen Tinh Thi , Azzidani Awad M , Magyar Kálmán 
Published: April 2011

Abstract
A high concentration of selegiline ((—)-deprenyl; 10−4M) potentiated low frequency (2 Hz) nerve stimulation-evoked release of [3H]noradrenaline from the isolated main pulmonary artery of the rabbit in the presence of neuronal (cocaine, 3 times 10−5M) and extraneuronal (corticosterone, 5 times 10−5M) uptake blockers, and inhibited the postsynaptic response. The transmitter-releasing action of 10−4M selegiline was inhibited by a moderate increase of external K+ (23&#x006d;̇6mM). Excess K+ by itself abolished the nerve-evoked release of [3H]noradrenaline but did not increase the resting outflow of radioactivity. Excess Ca2+ (7&#x006d;̇ mM) increased the stimulation-evoked transmitter release. In the presence of excess Ca2+, selegiline (10−4M) was effective in increasing the [3H]noradrenaline release in response to nerve-stimulation. Excess Ca2+ partly antagonized the postsynaptic inhibitory action of selegiline. In Ca2+-free, 1 mM EGTA-containing Krebs solution both the nerve-evoked 3H release and the transmitter releasing action of selegiline were abolished, in agreement with the ‘Ca-hypothesis’. The voltage-dependent K+-channel blocker, 4-ami-nopyridine (10−5M), increased the nerve-stimulation-evoked release of tritium from arteries. If selegiline was also present in the perfusion medium the nerve-evoked transmitter release further increased. 4-Aminopyridine completely antagonized the inhibitory action of selegiline on the postsynaptic contraction.
Effect of 8-phenyltheophylline, enprofylline and hydrochlorothiazide on glycerol-induced acute renal failure in the rat
Authors: Yates M S , Bowmer C J , Kellett R , Collis M G 
Published: April 2011

Abstract
The adenosine antagonist 8-phenyltheophylline (8-PT) is a diuretic in normal rats and can ameliorate glycerol-induced acute renal failure (ARF) in this species. To define which action of 8-PT is important in its salutary effect in ARF, we have compared its effects with those of enprofylline (a xanthine with little affinity for adenosine receptors) and with those of the tubular diuretic hydrochlorothiazide. In one series of experiments, groups of rats with ARF of 24 h duration were given a single dose of drug or vehicle. Only 8-PT enhanced urine volume when compared with the vehicle-treated group. In a second set of experiments, groups of glycerol-injected rats received drug or vehicle treatment (i.p.) twice daily for 2 days. Rats which received a course of 8-PT treatment had significantly lower plasma urea and creatinine concentrations, a higher glomerular filtration rate, a lower kidney weight and improved kidney morphology when compared with vehicle-treated rats. The only beneficial effect noted after enprofylline treatment was an improved kidney morphology. Hydrochlorothiazide treatment compared with vehicle treatment did not ameliorate any index of renal function but resulted in significant elevations in plasma urea and creatinine levels. The inability of enprofylline or hydrochlorothiazide to mimic the effects of 8-PT in ARF indicate that the effects of 8-PT are probably associated with adenosine receptor blockade and not with a tubular diuretic action.
Relationship between antipyrine elimination rate constant, clearance and volume of distribution in the rat
Authors: Svensson Craig K 
Published: April 2011

Abstract
While the relationship between the inverse of antipyrine half-life and clearance has been shown to be approximately linear in man, a recent report indicated that there was no significant relationship between antipyrine elimination rate constant (λ) and clearance (CL) in the rat. Since this relationship is critical to the use of non-invasive methods to estimate drug metabolizing capacity, we have re-examined the relationship between λ and CL in the rat. A significant correlation (r = 0·887) was found between antipyrine λ and CL, while only a weak relationship (r = 0·442) was found between λ and volume of distribution. These data support the use of non-invasive methods to estimate antipyrine elimination in the rat when invasive methods need to be avoided.
Effect of ibuprofen and indomethacin on human plasma melatonin
Authors: Surrall K , Smith J A , Bird H , Okala B , Othman H , Padwick D J 
Published: April 2011

Abstract
Ibuprofen reduced human plasma melatonin (MT) after 2 h when administered orally (400 mg) at 2400h. Increasing plasma concentrations correlated well with increasing inhibition of serum MT levels during this time. Maximum plasma ibuprofen coincided with minimum plasma MT in 3 out of 4 volunteers. Although two volunteers exhibited a partial recovery in MT levels, concentrations after 6 h were significantly less than 0600h values in drug-free volunteers. Administration of ibuprofen (400 mg) at 1800h delayed the nocturnal surge of plasma MT. When a slow release preparation of indomethacin (75 mg) was administered at 1800h, the dark phase rise of plasma MT was completely prevented. Thus the longer acting cyclooxygenase inhibitor exhibited a longer lasting inhibition of plasma MT concentration.
Choice and concentration of contractile agent influence responses of rat aorta to vascular relaxant drugs
Authors: O'Donnell Stella R , Wanstall Janet C 
Published: April 2011

Abstract
Concentration-response (relaxation) curves to diltiazem, forskolin, isobutylmethylxanthine (IBMX), procaterol, isoprenaline and sodium nitrite were obtained on isolated ring preparations of rat aorta contracted either submaximally or maximally with noradrenaline or KCl. Diltiazem was more potent on KCl-contracted than on noradrenaline-contracted preparations whether the preparations were submaximally or maximally contracted. The other relaxant drugs were at least 20-fold less potent against KCl than against noradrenaline, but only on maximally contracted preparations. On submaximally-contracted preparations there was no potency difference between preparations contracted with these two contractile agents. Increasing the KCl concentration had a marked influence on the location of the concentration-response (relaxation) curves to all the drugs except diltiazem. This influence was different for drugs that act via cyclic AMP and those that act via cyclic GMP. It is concluded that both the choice of contractile agent (noradrenaline or KCl) and the concentration (especially of KCl) influence relaxant responses of rat aorta to vasodilator drugs.
Stability of insulin mixtures in disposable plastic insulin syringes
Authors: Adams P S , Haines-Nutt R F , Town R 
Published: April 2011

Abstract
The miscibility of short and long acting porcine, human and bovine insulins has been investigated using HPLC. Soluble insulin is rapidly lost from solution when mixed with both isophane and zinc insulin, although the mechanism may be different in these two cases. The time for up to 50% or more to be lost is often less than 2 min. The percentage lost is dependent upon the ratio of the mixture and the type and origin of the insulin. In the case of soluble: zinc mixtures it is greatest for porcine and least for bovine, in the case of soluble: isophane mixtures it was least for human and greatest for bovine. The greater the original amount of soluble insulin present the less the loss. The results help explain recent clinical reports that mixtures of soluble and zinc insulins fail to achieve satisfactory control of post-prandial blood sugar levels.
Effects of glucagon on cAMP accumulation and ketogenesis in hepatocytes from euthyroid and hypothyroid rats
Authors: Shaheen Omar , Otham Sadeq , Al-Turk Walid A , Sliman Naif 
Published: April 2011

Abstract
The resistance to the effects of glucagon was studied in isolated hepatocytes prepared from male rats treated with 6N-propyl-2-thiouracil (PTU). Incorporation of [14C]oleate into ketone bodies in response to various concentrations of glucagon (10−5 to 10−10 M) was reduced in hepatocytes from hypothyroid rats compared with the euthyroid group. The reduced sensitivity to the effects of glucagon on ketogenesis after treatment with PTU was associated with a reduced ability of those hepatocytes to maintain cyclic adenosine-3’,5’- monophosphate (cAMP) at levels required to stimulate ketogenesis. The concentration of cAMP in response to glucagon (10−5 to 10−10 M) was diminished in hepatocytes from hypothyroid rats, compared with those from euthyroid animals.
Comparison of the mode of action of succinylcholine and succinylmonocholine on rat skeletal muscle after denervation
Authors: Andrews Margaret M , Doro Catherine , Nolan Jennifer , Whittaker R 
Published: April 2011

Abstract
The effects of equimolar concentrations (3.0 × 10−5 M) of succinylcholine (SCh) and succinylmonocholine (SMC) were studied in-vitro at 20°C in rat extensor digitorum longus muscle (EDL) 0–147 days after common peroneal nerve section. Analysis of simultaneous measurements of K+ efflux (mmolL−1 g−1) and contracture tension (mN) to SCh showed that there was a rapid increase in the mean values of both parameters up to 22–28 days after denervation (7.7 mmolL−1 g−1, 36 mN). At the end of the period studied, the contracture response declined to 4.0 mN whilst the capacity for K+ efflux remained relatively high (4.8 mmolL−1 g−1) in comparison with normal contralateral EDL muscle (n = 82) K+ efflux measurements (0.62 mmolL−1 g−1). A significant correlation (r = 0.86, P ≤ 0.001) was found between SCh-induced K+ efflux and contracture tension 1–56 days following nerve section which indicated that the development of the contracture response and K+ efflux were concomitant during the period specified. The ratios of maximum contracture tension/K+ efflux in response to SCh and SMC, 18–22 days after denervation were similar, 4.9 and 5.0, respectively. Results indicated that the mode of action of each agent was similar in denervated rat skeletal muscle, and that they were equally potent in their hyperkalaemic potential. Results of comparative measurements of membrane depolarization and contracture tension in response to SCh and SMC showed that both agents produced quantitatively similar responses at 7 and 14 days after denervation; 23 mN c.f. 20 mN/17 mV c.f. 15 mV, and 32 mN c.f. 33 mN/20 mV c.f. 19 mV, respectively. It is proposed that SMC would not be a suitable substitute for SCh for use with either normal or denervated skeletal muscle.
The synergistic effects of concurrent administration to rats of EDTA and sodium salicylate on the rectal absorption of sodium cefoxitin and the effects of inhibitors
Authors: Nishihata Toshiaki , Lee Chia-Shun , Rytting J Howard , Higuchi Takeru 
Published: April 2011

Abstract
Plasma levels of cefoxitin, as enhanced by rectal coadministration of sodium salicylate, were reduced by concurrent administration of &lt;0.5 mg mL−1 N-ethylmaleimide (NEM) or p-chloromercuriphenylsulphonic acid, sodium salt (p-CMP). Concentrations of these inhibitors above 1 mg mL−1 resulted in enhanced peak plasma values of cefoxitin. This did not occur after coadministration with either ethylenediaminetetraacetic acid (EDTA) or polyoxyethylene-23 lauryl ether (POE). Ouabain and 2,4-dinitrophenol (DNP) suppressed plasma cefoxitin levels in the presence of salicylate and the enhancing effects of EDTA and POE when EDTA and POE were administered at low doses. At higher concentrations of EDTA and POE, DNP had little effect, while ouabain had little effect on POE and only partially suppressed the effects of EDTA. Plasma concentrations of cefoxitin after coadministration with salicylate and POE together, or with EDTA and POE together, were about the same as expected from summing the plasma levels resulting from coadministration of each adjuvant individually at the same concentrations. However, combined administration of salicylate and EDTA with cefoxitin yielded plasma cefoxitin concentrations which were much higher than expected from the sum of their individual actions.