bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Different β-Adrenergic Agonists on the Intestinal Absorption of Galactose and Phenylalanine
Authors: Díez-Sampedro Ana , Pérez Mercedes , Cobo M Teresa , Martínez J Alfredo , Barber Ana 
Published: April 2011

Abstract
Nutrient transport across the mammalian small intestine is regulated by several factors, including intrinsic and extrinsic neural pathways, paracrine modulators, circulating hormones and luminal agents. Because β-adrenoceptors seem to regulate gastrointestinal functions such as bicarbonate and acid secretion, intestinal motility and gastrointestinal mucosal blood flow, we have investigated the effects of different β-adrenergic agonists on nutrient absorption by the rat jejunum in-vitro.
When intestinal everted sacs were used the β2-agonist salbutamol had no effect either on galactose uptake by the tissue or mucosal-to-serosal flux whereas mixed β1- and β2-agonists (isoproterenol and orciprenaline) and β3-agonists (BRL 35135, Trecadrine, ICI 198157 and ZD 7114) inhibited galactose uptake and transfer of D-galactose from the mucosal-to-serosal media across the intestinal wall (although the inhibiting effects of isoproterenol and Trecadrine were not statistically significant). In intestinal everted rings both Trecadrine and BRL 35135 clearly reduced galactose uptake, the effect being a result of inhibition of the phlorizin-sensitive component. Total uptake of phenylalanine by the intestinal rings was also reduced by those β3-adrenergic agonists.
These results suggest that β1 and β3-adrenergic receptors could be involved in the regulation of intestinal active transport of sugars and amino acids.
Nicotine-induced Perturbations on Heart Rate, Body Temperature and Locomotor Activity Daily Rhythms in Rats
Authors: Pelissier Anne Laure , Gantenbein Manon , Bruguerolle Bernard 
Published: April 2011

Abstract
The aim of this study was to evaluate the influence of nicotine on the daily rhythms of heart rate, body temperature and locomotor activity in unrestrained rats by use of implanted radiotelemetry transmitters.
The study was divided into three seven-day periods: a control period, a treatment period and a recovery period. The control period was used for baseline measurement of heart rate, body temperature and locomotor activity. During the treatment period three rats received nicotine (1 mgkg−1, s.c.) at 0900 h. Three rats received saline under the same experimental conditions. Heart rate, body temperature and locomotor activity were continuously monitored and plotted every 10min. During the three periods a power spectrum analysis was used to determine the dominant period of rhythmicity. If daily rhythms of heart rate, body temperature and locomotor activity were detected, the characteristics of these rhythms, i.e. the mesors, amplitudes and acrophases, were determined by cosinor analysis, expressed as means ± s.e.m. and compared by analysis of variance.
Nicotine did not suppress daily rhythmicity but induced decreases of amplitudes and phase-advances of acrophases for heart rate, body temperature and locomotor activity. These perturbations might result from the effects of nicotine on the suprachiasmatic nucleus, the hypothalamic clock that co-ordinates biological rhythms.
Effect of Particle Size and Coating Level on the Diffuse Reflectance of Wax Matrices
Authors: Dredán J , Zelkó R , Antal I , Bihari E , Rácz I 
Published: April 2011

Abstract
The aim of this study was to examine the influence of particle size and extent of coating on the diffuse-reflectance spectra of wax matrices containing embedded potassium chloride.
Near-infrared spectroscopy was used to analyse the diffuse-reflectance characteristics of the prepared multi-particulate matrices without destructive sample preparation. A 2-factor, 3-level face-centred central composite design was selected to construct a second-order polynomial model which described the effect of particle size and amount of coating on the intensity of the diffusely reflected light. A non-linear model was used to demonstrate the effect of the selected parameters on the intensity of the reflected light; good correlation was obtained between experimental and predicted results. The results indicated that the extent of coating and the particle size of the examined systems in the selected particle size-range modified the intensity of the reflected light.
It can be concluded that near-infrared spectroscopy is a sensitive means of measuring not only the particle size of powders (substrates and their mixtures), but also that of coated multi-particulate systems.
An Investigation of the Mechanism of Flux Across Polydimethylsiloxane Membranes by use of Quantitative Structure-Permeability Relationships
Authors: Cronin M T D , Dearden J C , Gupta R , Moss G P 
Published: April 2011

Abstract
Quantitative structure-permeability relationships (QSPRs) based on readily calculated parameters have been developed to study penetration across a polydimethylsiloxane membrane.
Maximum steady-state flux values for 256 compounds through a polydimethylsiloxane membrane were taken from previous studies. Forty-three physicochemical parameters were calculated for each compound and their significance to flux determined. Removal of fourteen outliers enabled derivation of a significant three-parameter QSPR based on the number of hydrogen-bond acceptor and donor groups and sixth-order path molecular connectivity. Models based on parameters important for penetration across human skin (log P and molecular weight) were comparatively poor.
This model suggests that the mechanism of flux across a polydimethylsiloxane membrane is based mainly on hydrogen-bonding effects; as such it occurs via a mechanism of action different from that of penetration of the skin in man.
Chitosan-EDTA Conjugate: A Novel Polymer for Topical Gels
Authors: Valenta Claudia , Christen Barbara , Bernkop-Schnürch Andreas 
Published: April 2011

Abstract
A recently developed chitosan-EDTA conjugate, neutralized with sodium hydroxide (NaChito-EDTA), has been tested for possible topical use. The technical properties and microbial stability of NaChito-EDTA have been compared with those of carmellose sodium (NaCMC), hydroxypropylmethylcellulose (HPMC), sodium polycarbophil (NaPCP) and sodium carbopol 980 (NaC980), well established gelatinizing agents.
NaChito-EDTA forms stable, colourless, completely transparent hydrogels at a polymer concentration of 0.5%. Of the polymers tested the novel polymer had the lowest incompatibility with multivalent cations and with ethanol, and much the best swelling properties. After 28 days of incubation at room temperature the rates of growth of the complete bacterial spectrum occurring in demineralized water and of Escherichia coli, serving as model strain representative of Gram-negative bacteria, were at least 2 log and 5–7 log, respectively, lower in NaChito-EDTA gels than in the other hydrogels. This antimicrobial activity of NaChito-EDTA can be explained by its highest binding affinity towards magnesium, which stabilizes the outer membrane of Gram-negative bacteria. However, this antimicrobial effect is insufficient to guarantee microbial stability. Further results showed that the antimicrobially acting polypeptide nisin can be recommended as an alternative novel preservative for NaChito-EDTA gels, because its antimicrobial spectrum could also be increased towards Gram-negative bacteria in combination with chelating excipients.
NaChito-EDTA seems, therefore, to be a promising novel polymer for topically-used gels, with advantages over well established gelatinizing agents.
Effect of Cyclosporin on Liver Antioxidants and the Protective Role of Vitamin E in Hyperoxaluria in Rats
Authors: Adhirai Marimuthu , Selvam Ramasamy 
Published: April 2011

Abstract
This study aimed to evaluate whether administration of cyclosporin to hyperoxaluric rats affects liver antioxidant status, and whether pretreatment with vitamin E reverses the effect.
Male Wistar rats were divided into two major groups of 40. One group was given vitamin E. Both major groups were then divided into four subgroups which received vehicle (olive oil), cyclosporin in olive oil (50 mg kg−1), 3% ammonium oxalate or cyclosporin + 3% ammonium oxalate for three days. The activities of liver lactate dehydrogenase, glycolic acid oxidase and xanthine oxidase, and the level of malondialdehyde, an indicator of lipid peroxidation, increased when cyclosporin was administered to hyperoxaluric rats. The levels of antioxidants ascorbic acid, vitamin E and reduced glutathione and the activities of glutathione-metabolizing enzymes were altered significantly when hyperoxaluric rats were treated with cyclosporin. All these enzymes and antioxidants showed highly significant correlation values, r. These changes were restored to near normal by pretreatment with vitamin E.
These findings suggest that cyclosporin-induced hepatotoxicity is aggravated in hyperoxaluria. This was almost totally prevented by pretreatment with vitamin E.
Biochemical and Pharmacological Characteristics of 3-Butyryl-8-methoxy-4-[(2-thiophenyl)amino]quinoline, a New Proton-pump Inhibitor, in Rabbit Gastric Microsomes and in Rats
Authors: Kim Kyu Bong , Chang Man Sik , Chung Young Kuk , Sohn Sang Kwon , Kim Sung Gyu , Choi Wahn Soo 
Published: April 2011

Abstract
We have investigated the properties of the newly synthesized proton-pump inhibitor, 3-butyryl-8-methoxy-4-[(2-thiophenyl)amino]quinoline (YJA20379–6), on gastric mucosal proton-pump (H+/K+-ATPase) activity, gastric acid secretion and gastroduodenal lesions in experimental rats.
YJA20379–6 markedly inhibited H+/K+-ATPase activity in rabbit isolated gastric mucosal microsomes, confirming its classification as a proton-pump inhibitor. The inhibitory efficacy of YJA20379-6 on the proton pump was approximately 14-times higher than that of omeprazole at pH 7.4. YJA20379–6 given intraduodenally had a potent inhibitory effect on gastric secretion in pylorus-ligated rats (ED50 22.9 mg kg−1) but was less active than omeprazole. Pretreatment of rats with YJA20379-6 dose-dependently protected the gastric mucosa from damage induced by water-immersion stress, indomethacin and absolute ethanol, and the duodenal mucosa from damage induced by mepirizole. Repeated administration of YJA20379-6 also dose-dependently accelerated the spontaneous healing of acetic acid-induced gastric ulcers.
These results suggest that YJA20379-6 has potent anti-secretory and anti-ulcer effects which are exerted by suppression of H+/K+-ATPase activity in gastric parietal cells. YJA20379–6 might be useful for the clinical treatment of peptic ulcer diseases.
The 5-HT and α-Adrenoceptor Antagonist Effect of Four Benzylisoquinoline Alkaloids on Rat Aorta
Authors: Catret M , Ivorra M D , D’ocón M P , Anselmi E 
Published: April 2011

Abstract
The action of four benzylisoquinoline alkaloids (two aporphines—glaucine and apomorphine, a benzylisoquinoline—papaverine and a bisbenzyltetrahydroisoquinoline—antioquine) on 5-HT-induced contraction in rat thoracic aorta has been examined and compared with that of the control drugs: ketanserin, nifedipine, prazosin and phentolamine. The relaxant action on 5-HT-induced contraction was contrasted with that on the contraction induced by noradrenaline and KCl.
The results obtained with control drugs show that ketanserin has clear selectivity for 5-HT receptors, whereas prazosin and phentolamine have high selectivity for the α1-adrenoceptor and nifedipine seems to have a more potent effect on KCl-induced contraction than on that induced by 5-HT or noradrenaline. The contraction evoked by 5-HT (10 μm) was inhibited in a concentration-dependent manner by all the alkaloids. The order of potency was: papaverine = glaucine &gt; apomorphine &gt; antioquine. Papaverine had a non-specific relaxant action on 5-HT-, noradrenaline- and KCl-induced contraction, antioquine had a weak relaxant action on the agonist assays, and glaucine and apomorphine inhibited noradrenaline- and 5-HT-induced contraction more potently than they inhibited the K+-depolarized response.
These results indicate that the aporphines assayed, S-glaucine and R-aporphine, had selective action against agonist (noradrenaline or 5-HT)-induced contraction rather than against KCl-depolarization of rat aorta. In contrast papaverine, a benzylisoquinoline alkaloid, relaxes all agents used non-selectively as could be expected from the lack of specificity that characterizes this alkaloid.
Interaction Between Substance P and β-Adrenergic Agonists in the Modulation of the Secretion of Fluid and Protein by the Rat Submandibular Gland
Authors: Iwabuchi Yoshiki , Kimura Tomohiko 
Published: April 2011

Abstract
The interactions between substance P and β-adrenergic agonists such as isoprenaline, dobutamine and terbutaline in the control of the secretion of fluid and protein from the rat submandibular gland have been examined.
Substance P elicited large volumes of saliva whereas isoprenaline, dobutamine and terbutaline elicited small volumes only. The secretion of fluid in response to substance P was markedly enhanced when substance P was administered in combination with isoprenaline or dobutamine but not when it was administered in combination with terbutaline. Isoprenaline elicited large amounts of protein, whereas substance P elicited small amounts. The secretion of protein in response to isoprenaline did not change when isoprenaline was administered in combination with substance P. The secretion of fluid and protein induced by substance P in combination with isoprenaline was antagonized by metoprolol and by spantide, but it was unaffected by pretreatment with ICI118551.
These results suggest that in the rat submandibular gland stimulation of β1-adrenoceptors but not of β2-adrenoceptors potentiates the secretion of fluid that is induced by stimulation of tachykinin receptors, whereas stimulation of tachykinin receptors does not enhance the secretion of protein that is induced by stimulation of β1-adrenoceptors.
Compatibility of Tropisetron with Glass and Plastics. Stability under Different Storage Conditions
Authors: Brigas F , Sautou-Miranda V , Normand B , Geneve S , Chopineau J 
Published: April 2011

Abstract
The compatibility of tropisetron (pure undiluted 1 mg mL−1 and diluted with 5% glucose or 0–9% NaCl (saline)) with glass, poly(vinyl chloride), polypropylene or polyethylene containers has been studied over a period of two weeks. The drug solutions were exposed to different light and temperature conditions. Tropisetron was assayed by high-performance liquid chromatography.
The results show that undiluted tropisetron is stable in polypropylene syringes for two weeks under all the storage conditions tested (daylight at room temperature, dark at room temperature, refrigerator at 4°C). Some variations in concentration were observed after dilution of tropisetron but these remained within 10% of the initial concentration. Tropisetron can be stored undiluted at 1 mg mL−1 in polypropylene syringes, although it is preferable to perform dilutions extemporaneously. Tropisetron diluted with 5% glucose or saline can be kept equally well in glass, poly(vinyl chloride) (Travenol bags) or polyethylene (ecoflac) containers.
Water-soluble β-Cyclodextnns in Paediatnc Oral Solutions of Spironolactone: Preclinical Evaluation of Spironolactone Bioavailability from Solutions of β-Cyclodextrin Derivatives in Rats
Authors: Kaukonen Ann M , Lennernäs Hans , Mannermaa Jukka-Pekka 
Published: April 2011

Abstract
Water-soluble derivatives of β-cyclodextrin have been considered for solubilization of spironolactone in the formulation of a safe liquid preparation for premature infants. The oral absorption of spironolactone was studied in rats to evaluate the need to adjust spironolactone dosage in prospective clinical studies. Spironolactone was administered in solutions of sulphobutyl ether β-cyclodextrin (SBE7) or dimethyl-β-cyclodextrin (DM-β-CyD) and also as spironolactone-containing powder papers (reference preparation). Spironolactone in SBE7 solution was administered intravenously to assess the extent of intestinal absorption from the different formulations.
Spironolactone and the metabolites 7α-thiospirolactone, 7α-thiomethylspirolactone and canrenone were determined in rat serum after intravenous administration of spironolactone. Half-lives for spironolactone, 7α-thiomethylspirolactone and canrenone were 0.72 ± 0.17, 1.5 ± 0.3 and 2.2 ± 0.3 h, respectively. Although, according to Cmax values, 7α-thiomethyl-spirolactone was the major serum metabolite in rats, higher AUC (area under the serum concentration-time curve) values were obtained for canrenone. After oral administration of spironolactone the bioavailabilities evaluated from the AUC values of 7α-thiomethylspirolactone were 27.5 ± 9.3%, 81.3 ± 28.8% and 82.8 ± 28.6% for powder papers, DM-β-CyD and SBE7 solutions, respectively.
The oral absorption of spironolactone by rats was better after administration of spironolactone in SBE7 and DM-β-CyD solutions than after administration as powder papers. Both cyclodextrin formulations enhanced spironolactone bioavailability to a similar extent despite some deacetylation of spironolactone in the presence of SBE7. A reduction of spironolactone dosage would be recommended during clinical studies with premature infants. These results indicate that SBE7 could be a safe and suitable excipient for the solubilization of spironolactone in paediatric formulations.
Ionic-diffusion Potential-dependent Transport of a New Quinolone, Sparfloxacin, Across Rat Intestinal Brush-border Membrane
Authors: Iseki Ken , Hirano Takeshi , Tsuji Kaori , Miyazaki Shozo , Takada Masahiro , Kobayashi Michiya , Sugawara Mitsuru , Miyazaki Katsumi 
Published: April 2011

Abstract
The mechanism of uptake of sparfloxacin, a new quinolone, by intestinal brush-border membrane vesicles was investigated to clarify whether there is a common transport process for new quinolones mediated by the diffusion potential across the intestinal membrane bilayer.
Sparfloxacin was taken up pH-dependently by rat intestinal brush-border membrane vesicles, behaviour analogous to that of organic cations including enoxacin and ciprofloxacin. Transient overshooting uptake of this quinolone was observed in the presence of an outward H+ gradient. Momentary dissipation of the H+ gradient by addition of carbonyl cyanide p-(trifluoromethoxy)phenylhydrazone did not affect the uptake of sparfloxacin, and a marked but incomplete reduction in the H+-sensitive overshooting uptake of sparfloxacin was apparent in the voltage-clamped brush-border membrane vesicles. Furthermore, a valinomycin-induced K+-diffusion potential (interior negative) and an inward Cl—-diffusion potential stimulated the initial uptake of Sparfloxacin at pH 5.5. Sparfloxacin uptake was inhibited by tetracaine and imipramine. The inhibitory effect of these cations correlated well with changes in membrane surface charges induced by the presence of tetracaine or imipramine.
These results indicate that sparfloxacin transport across the brush-border membrane depends upon the inside-negative ionic diffusion potential, that the H+- or K+-diffusion-potential-dependent uptake of sparfloxacin by intestinal brush-border membrane vesicles is affected by the membrane surface potential and that inhibition of sparfloxacin uptake originates from changes in the membrane surface potential caused by the organic cations.
Adenosine Receptor mRNA Levels During Postnatal Renal Maturation in the Rat
Authors: Morton M J , Sivaprasadarao A , Bowmer C J , Yates M S 
Published: April 2011

Abstract
Adenosine may affect the pattern of intrarenal blood flow during renal development. It provides an angiogenic stimulus for the growth of new blood vessels and may be involved in compensatory renal growth. It is therefore of interest to investigate the expression of adenosine receptor genes during postnatal renal development. In the present study this was carried out by measuring adenosine receptor mRNA levels in rats aged between 2 and 60 days.
The order of abundance of adenosine receptor mRNA levels in 60-day-old rats was A2A &gt; A2B ≥ A1 &gt; A3. A1 receptor mRNA levels showed only small changes with increasing age although, by contrast, A3 receptor mRNA increased markedly with age with levels at 60 days twenty-fold greater than at 2 days. A2A receptor mRNA levels declined during renal maturation with transcript numbers four- to fivefold that at 12–18 days compared with numbers at 60 days. By contrast to the A2A receptor, there were no significant changes in the renal levels of A2B receptor mRNA during kidney maturation.
During postnatal renal maturation, the levels of mRNA for A2A and A3 adenosine receptor subtypes undergo marked changes which may be related to functional maturation, morphological development, or both.
Alteration of Activities of Hepatic Antioxidant Defence Enzymes in Developing Chick Embryos After Glucocorticoid Administration - A Factor to Produce Some Adverse Effects?
Authors: Lee Jung Wha , Iwatsuru Motoharu , Nishigori Hideo 
Published: April 2011

Abstract
Liver tissue is one of the principal targets of glucocorticoids, therefore changes in the balance between hepatic oxidative and reductive capacity may greatly influence adverse effects of glucocorticoid therapy. In this study, effects of glucocorticoid on the activities of hepatic antioxidant defence enzymes were examined by using developing chick embryos.
After the administration of 0.25 μmol hydrocortisone sodium succinate, a typical glucocorticoid, to 15-day-old chick embryos, glutathione peroxidase, glutathione reductase, catalase and superoxide dismutase in the liver generally began to decrease at around 4 h, reaching 60–70% of control levels between 24 and 48 h. These changes were observed much earlier than the elevation of the hepatic thiobarbituric acid reacting substance (TBARS) level which began to increase from 20 h, reaching about six times the control level at 48 h after hydrocortisone administration. Conversely, the elevated TBARS level decreased back to the normal level with the recoveries of these enzyme activities. Furthermore, it was found that the aniline hydroxylase activity, measured as a marker of oxidative activity, began to increase after around 12 h.
These results suggested that TBARS levels were possibly produced by the suppression of antioxidant defence abilities and the significant induction of oxidative activity in the liver by glucocorticoid. As the elevated TBARS in the liver can be distributed to tissues, TBARS will be involved in the occurrence of some of the glucocorticoid-induced adverse effects such as cataract formation.