bluuebunny/crossref_metadata_2025_split huggingface dataset:
An assay procedure to compare sorptive capacities of activated carbon dressings: the detection of impregnation with silver
Authors: Schmidt Richard J , Shrestha Tirtha , Turner Terence D 
Published: April 2011

Abstract
A semiquantitative assay procedure for the estimation of uptake of diethylamine by activated carbon dressings has been developed. The procedure involves the use of Nessler’s reagent as a comparative indicator. The use of diethylamine allows the concomitant detection of silver with which the dressings may be impregnated. The implications of silver/amine complex formation during dressing use are discussed. Quantification of the silver content of one such fabric was carried out by atomic absorption spectrophotometry. A silver content of 2770 ppm was found. It is suggested that this method might be suitable for adoption as the basis for a pharmacopoeial assay procedure for activated carbon dressings.
Concentration and Time-dependent Inter-relationships for Cytotoxicities of Nitrogen Mustard Drugs against Lymphoblasts In-vitro
Authors: Ehrsson Hans , Wallin Inger , Ringborg Ulrik 
Published: April 2011

Abstract
Peripheral lymphoblasts were exposed either to different initial concentrations of the alkylating agents (melphalan, chlorambucil or phenylacetic acid mustard) using a fixed incubation time or a constant initial concentration with variable exposure times. The cytotoxic activity was evaluated as the inhibition of [3H]methylthymidine incorporation into the trichloroacetic acid-insoluble fraction of the cells. The concentration-time relationships were evaluated by calculating the amount of drug which had chemically reacted in the incubation system. Melphalan showed lower cytotoxicity at short exposure times and high drug concentrations, while chlorambucil exhibited higher cytotoxicity at longer exposure times. In the latter case the effect could be accounted for by the cytotoxic activity of monohydroxy chlorambucil which was formed in the incubation system.
Effects of Various Ginseng Saponins on 5-Hydroxytryptamine Release and Aggregation in Human Platelets
Authors: Kimura Yoshiyuki , Okuda Hiromichi , Arichi Shigeru 
Published: April 2011

Abstract
The effects of various ginseng saponins isolated from red ginseng roots, on aggregation and 5-hydroxytryptamine release (5-HT) human platelets have been investigated. Among the six saponins tested, only ginsenoside Rg1 inhibited adrenaline- and thrombin-induced platelet aggregation and 5-HT release dose-dependently, at concentrations of 5 to 500 μg mL−1. Ginsenoside Rg1 had no effect on adrenaline- and thrombin-induced arachidonic acid release and diacylglycerol production. But it did reduce the elevation of cytosolic free calcium concentration (Ca2+)i shown in the second phase induced by adrenaline and thrombin, at concentrations of 10 to 500 μg mL−1. Those data suggest that the inhibitory effects of ginsenoside Rg1 on 5-HT release from, and aggregation of, platelets might be due to the reduction of (Ca2+)i elevation at the second phase induced by adrenaline and thrombin. The results suggest that ginsenoside Rg1 in red ginseng roots may be active as a drug in the treatment of artheroscleorosis and thrombosis.
The Effect of Acute and Chronic Administration of Morphine and Morphine Withdrawal on Intestinal Transit Time in the Rat
Authors: Brown Nicola J , Coupar Ian M , Rumsey R David E 
Published: April 2011

Abstract
The effects of acute and chronic morphine administration and of morphine-withdrawal on intestinal transit time of a liquid meal were investigated using rats. Many experiments have assessed the effects of acute morphine administration on intestinal transit, but the intestinal effects of chronic morphine administration have been neglected. Our results showed no significant differences between morphine-dependent and control animals when assessing the leading edge of the liquid meal infusion, its distribution and geometric centre (G.C.). However, during naloxone-precipitated withdrawal from morphine, the leading edge of the infusion and its G.C. were significantly distal to values obtained from other groups. Acute morphine administration caused delayed intestinal transit of a meal infusion, an effect partly caused by significant retention of the infusion in the stomach and duodenum. The leading edge of the meal infusion and G.C. were significantly proximal to values obtained from other groups of animals. The results show that morphine-dependent rats develop complete tolerance to the delayed intestinal transit of a meal observed after acute morphine administration and that withdrawal from morphine accelerates intestinal transit of a liquid meal.
Effect of Alkylxanthines on Gentamicin-induced Acute Renal Failure in the Rat
Authors: Kellett R , Bowmer C J , Collis M G , Yates M S 
Published: April 2011

Abstract
Adenosine antagonists have been previously shown to be of benefit in some ischaemic and nephrotoxic models of acute renal failure (ARF). In the present study, the effects of three alkylxanthines with different potencies as adenosine antagonists 8-phenyltheophylline, theophylline and enprofylline, were examined in rats developing acute renal failure after 4 daily injections of gentamicin (200 mg kg−1). Renal function was assessed by biochemical (plasma urea and creatinine), functional (urine analysis and [3H]inulin and [14C]p-aminohippuric acid clearances) and morphological (degree of necrosis) indices. The various drug treatments produced improvements in some, but not all, measurements of renal function. However, any improvement produced by drug treatment was largely a result of a beneficial effect exerted by its vehicle (polyethylene glycol and NaOH). The lack of any consistent protective effect noted with the alkylxanthines tested in the present study indicates that adenosine plays little, if any, pathophysiological role in gentamicin-induced ARF.
Enhanced bioavailability of morphine after rectal administration in rats
Authors: Katagiri Yoshihiro , Itakura Tadanori , Naora Kohji , Kanba Yasuhiro , Iwamoto Kikuo 
Published: April 2011

Abstract
Plasma morphine levels and the area under the plasma concentration-time curve (AUC) after i.v. (10 mg kg−1), p.o. (100 mg kg−1) and rectal (unrestricted or restricted to 1.5 cm from the anus, 10 mg kg−1) administration of morphine hydrochloride were determined in 10 or 11-week-old male Wistar rats to compare bioavailability of morphine after the rectal dosage with that after oral administration. The AUC value after oral administration (15 μg min mL−1), which was normalized by the dose, was only one-tenth of that after i.v. dosing (151 μg min mL−1). In contrast, the AUC after rectal administration (unrestricted, 133 μg min mL−1; restricted, 142 μg min mL−1) was almost comparable with that after i.v. administration. From the comparison of these AUC values, the extent of systemic availability of morphine after rectal (unrestricted or restricted) and p.o. administration was estimated to be approximately 90 and 10%, respectively.
Reversal of neuroleptic-induced catalepsy by novel aryl-piperazine anxiolytic drugs
Authors: McMillen Brian A , Scott Sara M , Davanzo Elizabeth A 
Published: April 2011

Abstract
The novel anxiolytic drug, buspirone, reverses catalepsy induced by haloperidol. A series of aryl-piperazine analogues of buspirone and other 5-hydroxytryptaminergic agonists were tested for their ability to reverse haloperidol induced catalepsy. Those drugs with strong affinity for 5-hydroxytryptamine1a receptors were able to reverse catalepsy. Drugs with affinity for other 5-HT receptors or weak affinity were ineffective. However, inhibition of postsynaptic 5-HT receptors neither inhibited nor potentiated reversal of catalepsy and leaves open the question as to the site or mechanism for this effect.
The influence of urotensin II on calcium flux in rat aorta
Authors: Gibson A , Conyers S , Bern H A 
Published: April 2011

Abstract
The fish neuropeptide urotensin II (UII, 10 nM) caused a 51% increase in uptake of 45Ca by segments of rat aorta; this increase was abolished by the Ca channel blocking drug nitrendipine (200 nM). 45Ca efflux was unchanged in the presence of UII, but was significantly increased following washout of the peptide; again, this increase was not observed in the presence of nitrendipine. The results provide direct evidence that the nitrendipine-sensitive component of the contractile response of rat aorta to UII involves mobilization of extracellular Ca, with subsequent activation of a Ca-induced, Ca-release process intracellularly. The mechanisms responsible for the nitrendipine-resistant component of the contractile response to UII remain to be established.
The Disposition of The Enantiomers of Warfarin Following Chronic Administration to Rats: Relationship to Anticoagulant Response
Authors: Pratt S K , Winn M J , Park B K 
Published: April 2011

Abstract
A model of chronic anticoagulation has been used to investigate the whole liver and subcellular disposition of the individual enantiomers of warfarin in the Wistar rat in relation to anticoagulant response. Consistent pharmacodynamic responses were achieved by dosing daily with R-warfarin (0·4, or 0·8 mg kg−1 day−1 i.p.) or S-warfarin (0·1 mg kg−1 day−1 i.p.). After the administration of increasing doses of R-warfarin, prothrombin times were dose-dependent (16·3 ± 0·5 s, 0·1 mg kg−1 day−1; 21·6 ± 1·7 s, 0·4 mg kg−1 day−1; 55·1 ± 9·0 s, 0·8 mg kg−1 day−1; results all measured 24 h after the final dose). Increasing doses of R-warfarin also produced increases in plasma, whole liver, and cytosolic concentrations of warfarin. However, there were no significant differences between the microsomal concentrations of R-warfarin in the three groups. The dose of S-warfarin required to produce a consistent and significant increase in the prothrombin time was four-fold lower than the dose of R-warfarin required to cause a similar effect. Plasma concentrations of S-warfarin were not significantly different from those seen after 0·4 mg kg−1 day−1 R-warfarin. Whole liver and cytosolic concentrations of the S-enantiomer were lower than those observed after a dose of 0·4 mg kg−1 day−1 R-warfarin. However, consistent with microsomal concentrations following increasing doses of R-warfarin, there was no significant difference between microsomal concentrations of R(+)- and S(—)-warfarin. Thus, in contrast to plasma, whole liver or liver cytosol, microsomal concentrations of warfarin do not appear to be related to either dose or pharmacological response. Our results appear consistent with the possibility of there being a saturable binding site in the microsomal fraction of the liver, with a capacity of approximately 4·0 μg g−1 protein.
Excitatory Effect of Morphine and Opioid Peptides in the Rat Isolated Colon
Authors: Laniyonu Adebayo , McCulloch Cameron , Pollock David 
Published: April 2011

Abstract
Morphine and the opioid peptides cause isolated segments of rat colon to contract and relax rhythmically. This study re-examines two hypotheses to explain this phenomenon: Release of 5-hydroxytryptamine (5-HT)/acetylcholine by morphine or inhibition of a tonically active non-adrenergic, non-cholinergic (NANC) inhibitory mechanism. Rhythmic contractions induced by morphine (5 × 10−6 M) were naloxone sensitive (10−6 M) but unaffected by methysergide (10−6 M), atropine (10−6 M) or pretreatment of rats with p-chlorophenylalanine (200 mg kg−1 i.p. for four days) which lowered the 5-HT level in the colon from 3·73 ± 0·83 mg g−1 in controls to 0·41 ± 0·06 mg g−1 (P &lt; 0·001). The pattern of rhythmic contractions produced by morphine was unlike those produced by 5-HT (5 × 10−6 M), acetylcholine (5 × 10−6 M) or potassium chloride (30 mM). Tetrodotoxin (10−6 M), apamin (10−8 M), clonidine (2 × 10−8 M), phentolamine (10−5 M) or oxprenolol (10−5 M) caused rhythmic contractions which were unaffected by naloxone. Clonidine contractions were inhibited by yohimbine (10−7 M) but not by prazosin (10−6 M). Electrical field stimulation at the peak of a contraction induced by morphine, apamin or Clonidine, produced an inhibitory response which was unaffected by atropine, phentolamine, propranolol and guanethidine (all 10−5 M). It persisted in colon segments from rats pretreated with reserpine or 6-hydroxydopamine. These results suggest that neither the 5-HT/acetylcholine hypothesis nor inhibition of the NANC mechanism adequately explains the excitatory effect of morphine in the rat colon.
On the Relevance of Non-steroidal Anti-inflammatory Drugs in the Prevention of Paralytic Ileus in Rodents
Authors: Pairet Michel , Ruckebusch Yves 
Published: April 2011

Abstract
In the mouse, the gastrointestinal transit of a charcoal marker, halved following the intraperitoneal administration of acetic acid, was no longer inhibited after pretreatment with the nonsteroidal anti-inflammatory drugs (NSAIDs), indomethacin, ketoprofen, piroxicam or ximoprofen (0·25–2·5 mg kg−1 orally). In the fasted rat, the migrating myoelectric complex pattern of the small intestine which was disrupted for about one hour by acetic acid was unaltered by pretreatment with indomethacin or ximoprofen (0·5 mg kg−1 i.p.). In the anaesthetized rat, the inhibition by about 50% of the gastrointestinal transit due to laparotomy, did not occur following treatment with NSAIDs. It is concluded that NSAIDs prevent the occurrence of chemically-induced and postoperative ileus in rodents, an effect probably related to the analgesic properties of NSAIDs.
Blood Pressure, the Renin-angiotensin System and Neurogenic Vasoconstriction in Pithed Rats
Authors: Henrion D , Eglème C , Criscione L , Wood J M 
Published: April 2011

Abstract
The influence of changing baseline blood pressure by various means, both related or unrelated to the renin-angiotensin system, on the pressor responses to spinal cord stimulation has been examined in the pithed rat. Mean arterial pressure and neurogenic vasoconstriction were higher in pithed rats with intact kidneys (2-kidney rats) than in nephrectomized pithed rats. Increasing blood pressure by infusion of vasopressin increased the pressor response to nerve stimulation in both 2-kidney and nephrectomized pithed rats. Decreasing blood pressure produced by administration of enalaprilat or hydralazine in 2-kidney pithed rats or by administration of hydralazine in nephrectomized pithed rats, decreased the pressor responses to nerve stimulation. Our results showed a positive correlation between the mean arterial blood pressure and the response to nerve stimulation in pithed rats. Therefore, we conclude that the pithed rat is an animal model which should be used with caution to study the interaction between the sympathetic nervous system and drugs which change baseline blood pressure.
The plasma disposition of sheep antibody (Fab) Fragments in the guinea-pig and rabbit
Authors: Timsina M P , Ostenfeld T , Hewick D S 
Published: April 2011

Abstract
The plasma elimination of sheep digoxin-specific Fab (fragment antigen-binding) antibody fragments has been studied after intravenous injection (1 mg kg−1) in guinea-pigs and rabbits using an enzyme-linked immunosorbent assay. The log concentration versus time profiles were best described by biexponential and triexponential functions for the response in the guinea-pig and rabbit, respectively. However, the elimination half-lives and apparent volumes of distribution were similar in both species (about 140 min and 120 mL kg−1, respectively). The value for the Fab distribution volume suggests that the antibody fragments distribute out of the vascular compartment but do not fully occupy the extracellular space. Our estimates of the latter, using thiocyanate as a marker, ranged from 220 to 327 mL kg−1 (rabbits and guinea-pigs, respectively). The distribution of Fab fragments in these two species differs significantly from that in the rat, where our earlier studies have shown that these antibody fragments are confined to the intravascular compartment with a distribution volume approximately equivalent to that of plasma (about 40 mL kg−1).
Brain tyrosine increases after treating with prodrugs: comparison with tyrosine
Authors: Topall Guy , Laborit Henri 
Published: April 2011

Abstract
After mice had been treated with L-tyrosine, O-phospho-L-tyrosine, L-tyrosine methyl ester or N-acetyl-L-tyrosine, tyrosine was assayed by HPLC coupled with fluorometric detection. O-Phospho-L-tyrosine behaved as a tyrosine prodrug after its hydrolysis by acid and alkaline phosphatases. After the intraperitoneal administration of O-phospho-L-tyrosine or the methyl ester, there was a substantial increase in bioavailability in terms of the effect of tyrosine. The two prodrugs were as powerful as tyrosine following oral administration. N-Acetyl-L-tyrosine was the least effective prodrug tested. The stability, solubility and bioavailability of O-phospho-L-tyrosine are consistent with proposing it for use as a tyrosine prodrug. In addition, it can be used parenterally. The use of a tyrosine aminotransferase inhibitor is necessary for limiting the hepatic breakdown of tyrosine and for increasing its bioavailability.
The effect of monoamine depletors on metrazol induced convulsions and brain γ-aminobutyric acid (GABA) contents in rats
Authors: Abed Wadie T 
Published: April 2011

Abstract
The thresholds for metrazol (pentylenetetrazol) clonic convulsions and brain γ-aminobutyric acid contents were significantly reduced after treatment with the monoamine depletors reserpine, tetrabenazine and p-chlorophenylalanine. Moreover, α-methyltyrosine, and α-methyl-m-tyrosine also lowered metrazol threshold seizures, but had no effect on brain α-aminobutyric acid contents. Furthermore, neither 5-hydroxytryptophan nor tranylcypromine had a significant effect on metrazol threshold seizures or brain α-aminobutyric acid contents, but blocked the changes previously induced by p-chlorophenyl alanine and reserpine.
Albumin Microspheres as Vehicles for the Sustained and Controlled Release of Doxorubicin
Authors: Jones C , Burton M A , Gray B N 
Published: April 2011

Abstract
Biodegradable albumin microspheres have been prepared with the intention of targeting doxorubicin preferentially to tumour tissue. A high-yielding microsphere manufacturing process has been developed that involved the denaturation of an aqueous protein emulsion by chemical and/or thermal crosslinking methods. Microspheres can be closely sized to a diameter of 25·3 ± 2·6 μm with the aid of microsieves. The in-vitro release of doxorubicin from albumin microspheres was measured using a continuous flow system. Doxorubicin release can be sustained for up to 10 days and the rate of release could be controlled by manipulating protein denaturation conditions between the temperatures 110–135°C in the presence of 0–2% gluturaldehyde. Release of doxorubicin was significantly faster in human plasma compared with isotonic saline.
An In-vitro Study of the Interactions Between Intravenous Induction Agents and the Calcium Antagonists Verapamil and Nifedipine
Authors: Bunting P , Ramsay T M , Pleuvry B J 
Published: April 2011

Abstract
Thiopentone, propofol and etomidate inhibit the contractions of the rat isolated atria and portal vein. The actions of thiopentone and propofol summate with those of verapamil and nifedipine. Verapamil potentiates the action of etomidate on both preparations. The depressant actions of thiopentone and propofol on the portal vein are associated with a reduced response to calcium. Etomidate does not reduce the response to calcium in this preparation.
Increased influence of endothelium in obese Zucker rat aorta
Authors: Auouet M , Delaflotte S , Braquet P 
Published: April 2011

Abstract
The ability of endothelium to alter contractile events in phenylephrine (PE)-triggered contraction has been tested on ring segments of the thoracic aorta removed from obese Zucker rats (plasma cholesterol 3·63 mM; n = 8) and from age matched lean rats (plasma cholesterol 2·38 mM; n = 8). In normal medium, PE (1 μM) elicited similar contractions in endothelium-denuded arteries of both strains. However, the presence of endothelium reduced these contractile events and the endothelium-dependent relaxation induced by carbachol (10 μM) was higher in obese rats. In rings incubated in Ca2+ free medium containing EGTA (1 mM), PE (1 μM) induced a phasic contraction and a sustained contraction following addition of Ca2+ (2·5 mM) to the medium. The phasic contraction was due to intracellular Ca + release, whereas the sustained response was dependent on extracellular Ca2+ influx. In endothelium-free preparations, the size of both the phasic and sustained contraction was similar for the two strains. The Ca2+ antagonist gallopamil (1 μM) reduced the sustained contraction of lean (24%) and obese (34%) rats without affecting the phasic contraction. In preparations possessing endothelium, the sustained, but not the phasic contraction, of both strains was inhibited. This inhibitory effect of endothelium on the sustained contraction was significantly higher in obese than in lean rats. Thus, it can be concluded that phenylephrine elicited quantitatively and qualitatively similar contractions in obese and lean rats. In both strains, the endothelium diminished the contraction induced by PE, however, this effect was more pronounced in obese rats than in lean ones. These results may explain, in part, the described absence of atherosclerotic lesions in the obese strain.
Supersensitivity of atherosclerotic rabbit aorta to ergometrine is mediated by 5-HT2 receptors
Authors: Kalkman H O , Neumann V , Brauner V 
Published: April 2011

Abstract
The concentration response curve of ergometrine in aortae from rabbits fed a high cholesterol diet for 12 weeks is biphasic. The first phase of the biphasic curve is antagonized by ketanserin, spiperone and cyproheptadine, but not by prazosin. pKB values are compatible with a 5-HT2 receptor mediated effect. The second phase is shifted to the right by prazosin, ketanserin and spiperone but not by cyproheptadine. In this case the pKB values are compatible with an α1-adrenoceptor mediated effect. The concentration response curves for ergometrine and phenylephrine in aortae from control rabbits are monophasic and pKB values again indicate an α1-adrenoceptor mediated response. Thus, ergometrine contracts the aortae of normal and cholesterol-fed rabbits via activation of α1-adrenoceptors. The supersensitivity observed in atherosclerotic strips seems to reflect the appearance of a high affinity component mediated by 5-HT2 receptors.
A simple intravenous infusion method in rodents for determining the potency of anticonvulsants acting through GABAergic mechanisms
Authors: Green A R , Murray T K 
Published: April 2011

Abstract
A simple method of intravenous infusion of convulsant drugs (pentetrazol and bicuculline) into the tail vein of rats has been used to determine seizure threshold and construct log-dose seizure threshold response curves for several anticonvulsant drugs (diazepam, phenobarbitone, pentobarbitone, chlormethiazole and valproate). It has been shown that an index of the dose required to increase seizure threshold by 50% (TI50) can be obtained using small numbers of animals. The advantages of this method over that of the subcutaneous pentetrazol method are several: small numbers of animals required, speed and reproducibility. The data also demonstrate the concordance between TI50 values obtained using pentetrazol and bicuculline as the convulsant agent. It is suggested that this method can be used routinely in screens of anticonvulsant drugs thought to work through GABAergic mechanisms.