bluuebunny/crossref_metadata_2025_split huggingface dataset:
The importance of reductive mechanisms for intestinal uptake of iron from ferric maltol and ferric nitrilotriacetic acid (NTA)
Authors: Barrand Margery A , Hider Robert C , Callingham Brian A 
Published: April 2011

Abstract
Intestinal iron absorption is thought to proceed with iron mainly in the ferrous form, yet the novel iron complex, ferric maltol is an effective oral preparation. Although possessing a high oil: water partition coefficient, ferric maltol does not diffuse across the intestine but donates its iron to the endogenous uptake system. Reduction of the ferric iron in the gut lumen appears to precede iron uptake both from ferric maltol and from ferric nitrilotriacetic acid (NTA) which is a non-penetrating iron ligand. Uptake of radiolabelled iron (59Fe) into isolated fragments of rat small intestine was inhibited by the ferrous chelator, bathophenanthroline sulphonate (BPS) and enhanced at low concentrations by the reducing agent ascorbic acid. Spectrophotometric evidence was obtained that ferrous ions are generated from these ferric complexes in the presence of ascorbic acid and other reducing agents. The rate of ferrous ion formation was independent of ferric maltol concentration at low ascorbic acid levels and decreased with increasing ferric maltol concentration at higher levels of ascorbate. Maltol has a high affinity for ferric ions and may delay reduction at higher concentrations. By contrast, a higher rate of ferrous ion generation was seen with ferric NTA and this increased with iron ligand concentration. Washings from the intestinal lumen also brought about ferrous ion formation from these ferric ligands. Gel filtration revealed these reducing factors to be of low molecular weight. The washings, however, interfered with 59Fe uptake into the isolated fragments, but when reducing fractions only from the filtered washings were used, enhanced iron uptake was seen. There are thus additional, heat stable factors, unrelated to reduction, present in-vivo in the gut lumen that interfere with iron absorption. Intestinal absorption of iron from ferric maltol appears to occur as with other ferric chelates by initial reduction of the metal. Since maltol has a high affinity for ferric iron it may limit ferrous ion generation but it has a low affinity for the reduced form of the iron and so can donate the ferrous iron once formed immediately to the intestinal cell surface carrier. Ferric maltol may thus act as a relatively non-toxic reservoir for soluble iron in the intestinal lumen.
Increased dopamine turnover in the ventral striatum by 8-OH-DPAT administration in the rat
Authors: Ahlenius Sven , Hillegaart Viveka , Wijkström Agneta 
Published: April 2011

Abstract
The administration of the 5-HT1A agonist 8-OH-DPAT (0.8 μmol kg−1 s.c. — 40 min) produced an increase in dopamine (DA) turnover, estimated by the quotient (DOPAC + HVA) DA−1, in the ventral striatum of the rat. No statistically significant effects were obtained in the dorsal striatum. The accumulation of 3-MT in pargyline-treated animals (375 μmol kg−1 s.c.— 60 min) was not affected by 8-OH-DPAT treatment (0.15-2.4 μmol kg−1 s.c.-30 min). These findings indicate that 8-OH-DPAT has weak antagonist properties at striatal DA receptors in normal rats. Both the 5-HT1A agonist flesinoxan (0.06–17.8 μmol kg−1 s.c. — 50 min) and the mixed 5-HT1 and 5-HT2 agonist 5-MeODMT (1.6–26.0 μmol kg−1 s.c. −50 min) produced a decrease in forebrain 5-HTP accumulation (striatum and neocortex), following decarboxylase inhibition by means of NSD-1015 in reserpine treated rats, indicating stimulation of central 5-HT receptors by these two compounds. At the same time, the DOPA accumulation in the ventral striatum was decreased by flesinoxan and increased by 5-MeODMT treatment. These observations show that, under these conditions, the decrease in DA synthesis is not directly coupled to the decreased 5-HT synthesis produced by flesinoxan, as previously demonstrated for 8-OH-DPAT. Taken together with previous observations, the present results suggest that 8-OH-DPAT, depending on the experimental conditions, is an agonist or antagonist at striatal DA receptors, in all probability due to partial DA receptor agonist properties of the compound.
Effects of Verapamil, Nifedipine and Flunarizine on Haemodynamics and Regional Blood Flows in Pentobarbitone-anaesthetized Rats
Authors: Waite R P , Pang C C Y , Walker M J A 
Published: April 2011

Abstract
Representative calcium antagonists from proposed class I (nifedipine), class II (verapamil) and class III (flunarizine) have been examined for effects on blood pressure, heart rate, ventricular pressures, ECG, cardiac output and regional blood flow in pentobarbitone-anaesthetized rats. Flow was measured by the microsphere technique. Low and high infusion rates of each drug were chosen to decrease mean arterial pressure by 25 and 40 mmHg, respectively. At equi-depressor infusion rates, all drugs equally decreased total peripheral resistance and slightly increased cardiac output and stroke volume. Heart rate was decreased by verapamil and flunarizine, but increased by nifedipine. Verapamil markedly decreased dP/dtmax of ventricular pressure and prolonged the PR-interval. Flunarizine was similar. Nifedipine decreased dP/dtmax and had no effect on the PR-interval of the ECG. Similar effects on regional blood flow were seen with the three drugs; flow to lungs, heart, liver, skeletal muscle and stomach increased. Correction for blood pressure changes, i.e. conductance, showed that vasodilatation occurred in all regions, with all drugs, except for the skin. Therefore, representatives from three sub-classes of calcium antagonists had similar effects on blood flow but different effects on the heart.
A pattern recognition study of acyclic ureide anticonvulsants
Authors: Khalil Maged , Weaver Donald F 
Published: April 2011

Abstract
A pattern recognition structure-activity study employing topological, geometric and physicochemical descriptors was performed on 27 acyclic ureide anticonvulsants. Twelve numerical descriptors were used as variables in a discriminant function analysis which categorized the ureide analogues with respect to their bioactivity. The results from the discriminant function analysis were interpreted to support a model for antiepileptic activity.
Chronic administration of MK-801 and the NMDA receptor: Further evidence for reduced sensitivity of the primary acceptor site from studies with the cortical wedge preparation
Authors: Beart Philip M , Lodge David 
Published: April 2011

Abstract
Cortical slices removed from rats pre-treated with MK-901 0.5 mg kg−1 twice a day for 7 days had reduced responses to N-methyl-D-aspartate (NMDA) relative to quisqualate and glutamate compared with control animals. Potencies of competitive (CPMP) and non-competitive (ketamine) NMDA antagonists appeared unchanged. These changes are consistent with a reduced density of NMDA receptors.
Potencies of mioflazine and its derivatives as inhibitors of adenosine transport in isolated erythrocytes from different species
Authors: Baer Hans P , Haq Afrozul , El-Soofi Ali , Serignese Vincent , Paterson Alan R P 
Published: April 2011

Abstract
The potency of mioflazine and related drugs (Janssen Pharmaceutica, Belgium) as inhibitors of adenosine transport in isolated erythrocytes from several species were measured and compared with those of dilazep and 6-(4-nitrobenzylmercapto)purine ribonucleoside (NBMPR). [8−3H]Adenosine was used as the permeant at 1 μM and incubation times were 10 s, and assays were conducted in the presence and absence of varying doses of potential transport inhibitors. The species investigated included mouse, hamster, rabbit, baboon and man. Dilazep was the most potent compound throughout with an IC50 of about 2 nM. In the mouse and hamster mioflazine and its derivatives were considerably less potent (IC50 values &gt; 200 nM) with the exception of R57974 with IC50 values of about 150 and 60 nM in mouse and hamster, respectively. In the man and baboon the derivatives had IC50 values in the same order of magnitude as NBMPR (&lt; 100 nM), and in the rabbit they had potencies close to that of NBMPR, ranging between 10–60 nM. Nucleoside transport inhibitors are of potential importance as host protectors during treatment of parasitic infections with cytotoxic nucleosides. Present data indicate that mioflazine and its derivatives are not very potent in some of the preferred animal models for parasitic infections (mouse, hamster) but are more effective in primates such as man and baboon.
Kynurenic acid blocks chemogenic nociception
Authors: Hajós Mihály , Engberg Göran 
Published: April 2011

Abstract
Previous studies have suggested a role of excitatory amino acids (EAA) in nociception. In the present study the effects of two antagonists of EAA-receptors on capsaicin-induced eye wipings were investigated. Intracisternally administered kynurenic acid, in contrast to intravenously administered MK-801, was found to effectively block the induced eye wipings. It is proposed that EAA, by activating non-NMDA receptors, are involved in the transmission of chemogenic nociception.
Stability of Liposomes on Long Term Storage
Authors: Hernández-Caselles T , Villalaín J , Gómez-Fernández J C 
Published: April 2011

Abstract
The effect of the lipid composition of liposomes on their storage for up to one year under different environmental conditions has been examined using 5,6-carboxyfluorescein as a model drug. When cholesterol and/or α-tocopherol were included in the liposomes, a significantly greater amount of dye was retained. The presence of α-tocopherol decreased the breakdown of phosphatidylcholine to lysophosphatidylcholine and also reduced the level of peroxidation. Carboxyfluorescein retention was further enhanced when liposomes were stored at 4°C or at room temperature (20°C) in an O2-free atmosphere. Lysophosphatidylcholine formation also slowed when the liposomes were kept at 4°C, or in an O2-free atmosphere. It is concluded that egg yolk lecithin liposomes may be stored for long periods at low temperature in an O2-free atmosphere or with added stabilizers such as cholesterol and α-tocopherol.
Normal Phase HPLC as a Model System of Specific Benzodiazepine-receptor Binding
Authors: Gilli Gastone , Pietrogrande Maria Chiara , Borea Pier Andrea 
Published: April 2011

Abstract
The hypothesis that benzodiazepines interact with their receptors in the CNS via hydrogen bonding mediated by the carbonyl and imine groups has been studied by correlating a physicochemical parameter affected by hydrogen bonds potentially accepted or donated by benzodiazepines with their binding constants to synaptosomal rat brain membranes. The reference physicochemical system chosen was normal phase high-performance liquid chromatography on μ-Bondapack NH2 (propylamine groups chemically bonded to porous silica) eluted with mixtures of n-hexane and 2-propanol. A strong correlation has been found for binding of the implicated groups to the column and to the receptor.
Augmented Potentiation of Renal Vasoconstrictor Responses by Thromboxane A2 Receptor Stimulation in the Alloxan-diabetic Rat
Authors: Hodgson W C , King R G , Boura A L A 
Published: April 2011

Abstract
Dose-response curves were obtained to bolus injections of noradrenaline (NA) and 5-hydroxytryptamine (5-HT) in blood and Krebs-perfused kidneys of male Wistar rats. Vasoconstrictor responses to both NA and 5-HT were significantly attenuated in blood-perfused kidneys of alloxan-treated 14 day diabetic rats compared with non-diabetic animals. Responses to low doses of NA were also significantly attenuated in Krebs-perfused kidneys from diabetic rats but responses to 5-HT were augmented. Dose-dependent potentiation of vasoconstrictor responses to NA and 5-HT in Krebs-perfused kidneys of both non-diabetic and diabetic rats occurred during infusion of the thromboxane A2 (TxA2)-mimetic U46619 ((15S)-hydroxy-11α, 9α-(epoxymethano) prosta-5Z, 13E-dienoic acid). The potentiation by U46619 (11 ng mL−1) was inhibited in both groups during infusion of the thromboxane receptor antagonist AH23848 ([1α(Z), 2β, 5α]-(±)-7-[5[[(1,1′-biphenyl)-4-yl]methoxy]-2-(4-morpholinyl)-3-oxocyclopentyl]-4-heptenoic acid). Infusion of 5-HT in Krebs-perfused kidneys of non-diabetic rats, causing a rise in perfusion pressure of similar magnitude to that produced by infusion of 111 ng mL−1 U46619, did not significantly affect responses to bolus injections of NA. Potentiation of vasoconstrictor responses to low concentrations of 5-HT by U46619 was significantly greater in Krebs-perfused kidneys of diabetic rats than kidneys from non-diabetic animals. Activation of vascular TxA2 receptors augments the vasoconstrictor effects of 5-HT in Krebs-perfused diabetic rat kidneys to a greater extent than in non-diabetic kidneys.
The effect of fatty acids on the rectal absorption of acyclovir in rats
Authors: Yamazaki Masaru , Itoh Soichi , SawanoI Masayoshi , Kobayashi Miki , Suzuki Sayaka , Komatsu Toshiaki , Tanabe Kazuhisa 
Published: April 2011

Abstract
The enhancing effect of fatty acids on the rectal absorption of acyclovir has been evaluated in rats. Acyclovir proved to be absorbed to the extent of 3 to 9% after oral administration. After rectal administration in the absence of absorption-promoter, the bioavailability of acyclovir was 37%. Its rectal administration with 4% sodium caprate resulted in enhanced bioavailability (81 ± 3%).
Effect of Recombinant Human Erythropoietin on New Anaemic Model Rats Induced by Gentamicin
Authors: Nagano Nobuo , Koumegawa Jun-Ichi , Arai Hirofumi , Wada Michihito , Kusaka Masaru 
Published: April 2011

Abstract
The effects of recombinant human erythropoietin (r-HuEPO) on haematological parameters were studied in rats in which uraemia and anaemia had been induced by gentamicin, an aminoglycoside antibiotic and a nephrotoxic agent. After the occurrence of slight polycythaemia, the red blood cell count, haematocrit and haemoglobin concentration decreased by 20–30% compared with those of the control (saline-injected) rats. At the end of gentamicin treatment, the endogenous serum EPO level had decreased to about 40% compared with that of control rats. Gentamicin-treated rats showed marked elevation of blood urea nitrogen, extensive tubular necrosis in the kidney and haemosiderin deposition in the spleen. In the osmotic fragility test, the fragility of erythrocytes significantly increased compared with that of control rats. These findings indicate that the anaemia induced by gentamicin is due not only to a deficiency of EPO but also to an enhancement of fragility of erythrocytes in an azotaemic environment. The administration of r-HuEPO during anaemia markedly increased red blood cell count, haematocrit and haemoglobin concentration. It is suggested that a gentamicin-treated rat is a useful and convenient anaemic model and r-HuEPO is useful for treatment of anaemia in acute renal failure.
α-Adrenoceptor Involvement in Swim Stress-induced Antinociception in the Mouse
Authors: Oluyomi Ademola O , Hart Stephen L 
Published: April 2011

Abstract
Three different intensities of swim stress produced stress-induced antinociception (SIA) in mice which was assessed either by the reduction in the number of abdominal constrictions produced by acetic acid or by an increase in reaction time on a hot-plate. The involvement of α-adrenoceptors in the three models of SIA was investigated using selective antagonists. SIA produced by the mild stress of a 30 s warm water swim was attenuated by idazoxan (0.5-1 mg kg−1), and by yohimbine at a dose (1 mg kg−1) which reduced antinociception produced by clonidine (12.5–50 μg kg−1). Indoramin (1–2 mg kg−1) did not affect this model of SIA, but reversed phenylephrine induced inhibition of the constrictions. A 3 min room temperature swim increased reaction times on the hot-plate and this naloxone-sensitive SIA was reduced significantly by prazosin (1–2 mg kg−1), idazoxan (0.5-1 mg kg−1) and yohimbine (0.5-1 mg kg−1) but enhanced by clonidine (0.5 mg kg−1) and noradrenaline (NA) (10 μg i.c.v.). Mice treated with 6-hydroxydopamine (60 + 60 μg i.c.v.) were hypersensitive to the hot-plate and did not develop SIA. Levels of noradrenaline in the brain (minus the cerebellum) were decreased after the room temperature swim SIA. The most severe stress of a cold water swim produced SIA on the hot-plate which was initially naloxone-insensitive. Both components of the cold water swim SIA were enhanced by NA (10 μg i.c.v.) and reduced by yohimbine (5 μg i.c.v.) whilst prazosin (5 μg i.c.v.) inhibited only the later naloxone-sensitive component; and these adrenoceptor agents potentiated cold water swim hypothermia induced by the cold water swim. These results show the differential involvement of α1-and α2-adrenoceptors in SIA in the mouse.
A disintegration test for vaginal tablets: comparison with BP test
Authors: Yamaguchi Masatoshi , Tanno Keiki , Sucibayashi Kenji , Morimoto Vasunori 
Published: April 2011

Abstract
To improve the disintegration test for vaginal tablets described in the British Pharmacopoeia (BP), a monitoring apparatus was added, and tested with seven effervescent and five non-effervescent tablets. A tablet was placed on the metal disc of the BP disintegration apparatus, and the guided plate was placed on the tablet. The guided plate moved downward smoothly in a cylinder as the tablet disintegrated. The movement was recorded by using a kymograph. The end-point and process of disintegration of the tablet were automatically recorded and the results obtained suggest that the modified test is a useful tool for the quality control of vaginal tablets.
Phenytoin-bupropion interaction: effect on plasma phenytoin concentration in the rat
Authors: Tekle A , Al-Khamis Khalil I 
Published: April 2011

Abstract
The effect of coadministration of bupropion (50 mg kg−1, p.o.) on the disposition profile of phenytoin has been studied in the rat. Plasma phenytoin concentration was measured serially for 10 h by HPLC. Bupropion had little or no effect on the pharmacokinetic parameters of an acutely administered dose of phenytoin. Following multiple doses of phenytoin however (i.e. steady state) the coadministration of bupropion resulted in significant increases in the elimination half-life (t 1/2), the area under the plasma concentration-time curve (AUC) and the time to maximum plasma concentration (tmax). Allowing for the limitations of single dose studies, these results point to a possible pharmacokinetic interaction between bupropion and phenytoin—the clinical significance of which needs to be assessed.
Susceptibility of bacterial isolates from AIDS patients to six fluoroquinolones
Authors: Lewin C S , Naden M , Watt B , Amyes S G B 
Published: April 2011

Abstract
The susceptibilities to ciprofloxacin, DR-3355 (S-(—)-ofloxacin), enoxacin, lomefloxacin, ofloxacin and PD127,391 of 69 significant bacterial isolates from HIV-positive patients at the City Hospital, Edinburgh have been determined. With the exception of the enterococci, most of the strains tested (including staphylococci, Escherichia coli and Pseudomonas aeruginosa) were susceptible to the fluoroquinolones. Ciprofloxacin was the most active of the clinically available drugs followed by ofloxacin, lomefloxacin and enoxacin. PD127,391 and DR-3355, the new fluoroquinolones tested, were at least as active as ciprofloxacin. Hence bacterial infections in AIDS patients should respond to fluoroquinolone therapy.
Dependence of the Renal Excretion of Theophylline on its Plasma Concentrations and Urine Flow Rate in Asthmatic Children
Authors: Agbaba D , Pokrajac M , Varagić V M , Pešić V 
Published: April 2011

Abstract
The dependence of the renal excretion of theophylline on its plasma concentration and urine flow rate has been investigated in asthmatic children of either sex. One group (age 12.25 ± 0.80, mean ± s.d. n = 8) was given aminophylline intravenously (i.v.), while another (age 10.00 ± 3.64 n = 14) was given a sustained release preparation of theophylline orally (single dose and repeated doses). Unchanged drug (11.6% ± 1.75) was excreted in the urine corresponding to a renal clearance of 10.6 ± 1.6 mL h−1 kg−1. Time dependence of the renal clearance of theophylline was found only after i.v. administration. Dependence of the renal clearance on urine flow rate was found both after i.v. administration and at steady state, but not after a single oral dose of theophylline. After oral administration, renal clearance of theophylline was higher at steady state than after a single dose (0.58 ± 0.06 L h−1 kg−1 vs 0.23 ± 0.03 L h−1 kg−1), while urine flow rate was lower (1.1 ± 0.5 mL min−1 vs 1.8 ± 0.9 mL min−1). High correlation of theophylline plasma concentration and theophylline excretion rate was obtained in 10 of 14 patients after administration of a single oral dose of the preparation (r = 0.8567 to 0.9830). There was no dose dependence of the renal clearance of the drug either after a single dose, or at steady state.
Regulation of Sympathetic and Parasympathetic Receptor Responses in the Rat Trachea by Epithelium: Influence of Mechanical and Chemical Removal of Epithelium
Authors: Doelman Cees J A , Oosterom Willem C , Bast Aalt 
Published: April 2011

Abstract
Removal of the epithelial layer of rat tracheal tissue did not affect the methacholine-induced contraction of the tracheal smooth muscle, but attenuated the (—)-isoprenaline induced relaxation (expressed as percentage of the methacholine contraction). In this way the epithelial layer seemed to play a role in the maintenance of an autonomic balance between sympathetic and parasympathetic receptor responses. Incubation of rat tracheal tissue with cumene hydroperoxide (3 × 10−5-10−3 M) resulted in a dose-dependent destruction and (partial) removal of the epithelial layer. Cumene hydroperoxide diminished muscarinic receptor responses of the rat trachea. Moreover, the autonomic balance between muscarinic and β-adrenoceptor responses was affected. The effects of cumene hydroperoxide on receptor responses were more pronounced after epithelium removal. The protective role of the epithelial layer of pulmonary tissue against oxidative stress has therefore been emphasized.
Effect of Anti-inflammatory Drugs on the Cardiotoxin-induced Hind-paw Oedema in Rats
Authors: Wang Jih-Pyang , Teng Che-Ming 
Published: April 2011

Abstract
Cardiotoxin, isolated from Naja naja atra venom, induced rat hind-paw oedema. This effect was suppressed by the pretreatment with dexamethasone or BW 755C, or subplantar co-injection with FPL 55712. Pretreatment with aspirin alone did not affect this response, while a significant reduction of cardiotoxin-induced paw oedema was achieved with aspirin in combination with diphenhydramine and methysergide. Subplantar co-injection of PAF antagonist, BN 52021 or L 652731, with cardiotoxin had no effect on paw oedema, whereas superoxide dismutase/catalase reduced this oedematous response. Cardiotoxin-induced paw oedema was also suppressed by pretreating the rats with isoprenaline. Pretreatment with rat anti-platelet plasma, which greatly reduced peripheral platelet count, did not affect cardiotoxin-induced paw oedema. Cardiotoxin did not trigger platelet aggregation or release reaction either in platelet-rich plasma or in washed platelet suspension. The oedematous response after subplantar co-injection of cardiotoxin with basic or acidic phospholipase A2 appeared to be only an additive effect. These results suggest that arachidonate metabolites, in which leukotrienes are most important, participated in cardiotoxin-induced paw oedema. Superoxide radical was also involved, while PAF and platelets showed little influence in this oedema effect.