bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Solvent Composition During Preparation on the Characteristics of Enoxacin Microparticles
Authors: Yang Qing , Reams Renee , Owusu-Ababio Godfried 
Published: July 2003

Abstract
We have studied the effect of the solvent system during preparation on the morphology, encapsulation efficiency, and release characteristics of enoxacin microparticles intended for localized delivery to the bone for the treatment of bone infections.
Microparticles of enoxacin were formulated using poly(glycolic acid-co-DL-lactic acid) (PGLA) of different viscosity grades by the solvent-evaporation technique. Micro-particles prepared with pure dichloromethane had smoother surfaces and less tendency to aggregate than microparticles prepared with dichloromethane-acetone solvent mixtures, which had porous surfaces.
Approximately 65% of the microparticles prepared with pure dichloromethane were &lt; 125 μm in diameter compared with 16% (approx.) of microparticles prepared with dichloromethane-acetone mixtures. Increasing the proportion of acetone from dichloromethane-acetone, 10:0, to dichloromethane-acetone, 1:1, resulted in an increase in encapsulation efficiency from 25 to 37%, and an increase in the yield of microparticles harvested from 39 to 51%. Although a further increase in the amount of acetone to dichloromethane-acetone, 1:9, had no significant effect on the yield, aggregation, or fraction of microparticles below 125 in diameter, the encapsulation efficiency increased to 56%. Approximately 55% of enoxacin was released in 24h for microparticles prepared with dichloromethane-acetone, 1:9, compared with 100% release in 10h and 2h for microparticles of the same size range prepared with dichloromethane-acetone, 1:1, and dichloromethane-acetone, 10:0, respectively.
The results suggest that the composition of the dichloromethane-acetone solvent system significantly influences the encapsulation efficiency and the rate of release of enoxacin from microparticles. This is important for the formulation of sustained-release enoxacin microparticles for the localized treatment of osteomyelitis.
Evaluation of the Factors Influencing Stomach-specific Delivery of Antibacterial Agents for Helicobacter pylori Infection
Authors: Shah Sweta , Qaqish Roula , Patel Vijay , Amiji Mansoor 
Published: July 2003

Abstract
Because Helicobacter pylori infection is localized in the gastric mucus layer and at the mucus layer-epithelial cell interface, we have developed amoxycillin- and metronidazole-containing chitosan microspheres for stomach-specific drug delivery.
Drug-loaded porous chitosan microspheres were prepared by simultaneous crosslinking and precipitation with sodium tripolyphosphate. The release of antibacterial agents into simulated gastric fluid (SGF, pH 1.2), and the stability and permeability through gastric mucin, were examined at 37°C. Because of the high porosity of drug-loaded chitosan microspheres, all the amoxycillin and metronidazole were released in 2 h. High-performance liquid chromatography assays of the antibacterial agents in SGF at 37°C indicated 40% degradation of amoxycillin after 10h. Metronidazole was completely stable for up to 24h in SGF. Amoxycillin and metronidazole were highly permeable through the gastric mucin gel layer.
The results of this study show that acid-stable antibacterial agents, such as metronidazole, that rapidly permeate the gastric mucus layer would be very effective for the complete eradication of H. pylori infection when delivered specifically at the site of infection in the stomach.
Comparison of Different Membranes with Cultures of Keratinocytes from Man for Percutaneous Absorption of Nitroglycerine
Authors: Minghetti Paola , Casiraghi Antonella , Cilurzo Francesco , Montanari Luisa , Marazzi Mario , Falcone Leonarda , Donati Vera 
Published: July 2003

Abstract
The permeability barrier function of cell-culture membranes to the permeation of nitroglycerine was evaluated to find an alternative to skin from man for ex-vivo skin-permeation tests.
The membranes were prepared, under submerged conditions, by inducing the growth of keratinocytes, from different donors, on a film of esterified jaluronic acid for different times (10, 20 and 30 days). Their permeability barrier functions were compared with those of some of the most widely used artificial membranes, silicone rubber (Silastic), cellulosic material (Cuprophan, Millipore HAWP), polysulphone membrane (Supor) and polytetrafluoroethylene membrane (TF-PTFE), and with those of biological membranes such as fresh and frozen skin, stratum corneum and epidermis from man, and hairless mouse skin. For each membrane the permeation profile was obtained and the flux was calculated. The permeation profiles for nitroglycerine were similar and linear in the first 2-3h for all the synthetic membranes tested except TF-PTFE. For this membrane the profile was linear throughout the period considered and the amount permeating in 24h (1603 μg cm−2) was significantly lower than those obtained for the other artificial membranes (between 1926 and 2508 μg cm−2). The amounts permeating through all the biological membranes in 24h were in the range 520 to 781 μg cm−2, except those for the keratinocyte-culture membranes, which were in the range 1730 to 2553 μg cm−2. Prolonging the growth period of cultured keratinocytes did not affect nitroglycerine permeation.
The findings suggest that these keratinocyte-culture membranes have some advantages—good reproducibility if obtained from the same donor; many membranes can be obtained from the same donor; the preparation is simple; they can be handled more easily than traditional cell-culture membranes; and they afford constant penetration rates for a longer period than synthetic membranes. The membranes could be used for preliminary in-vitro permeation studies.
Influence of Infused Catecholamines on the Pharmacokinetics of Cocaine and Benzoylecgonine Formation after Bolus Dose or Continuous Cocaine Administration in the Rat
Authors: Mets Berend , Jamdar Subhash , Diaz Jaime 
Published: July 2003

Abstract
The purpose of this study was to determine whether a catecholamine infusion administered to simulate a stress state could alter the pharmacokinetics of administered cocaine and effect the formation of benzoylecgonine, its major metabolite, in the rat. In a previous investigation we determined that catecholamine infusion enhanced the toxicity of continuous cocaine infusion by reducing the time before the onset of convulsions and respiratory arrest. We postulated that this enhanced toxicity was an effect of catecholamines on the pharmacokinetics of cocaine.
To test this hypothesis we studied plasma cocaine and benzoylecgonine disposition after intravenous bolus administration of cocaine (5 mg kg−1) to 19 male Sprague-Dawley rats and to 10 rats which received an initial loading-dose cocaine infusion of 1 mg kg−1 min−1 (for 5 min) followed by continuous infusion of 100 μgkg−1 min−1. Rats in both studies randomly received either continuous catecholamine infusion comprising adrenaline (7.25 μg mL−1), noradrenaline (4.4 μg mL−1) and dopamine (8.0 μg mL−1) or saline, administered at a similar rate. Bolus dose cocaine administration, simultaneously with catecholamine infusion, resulted in significantly higher Cmax levels for cocaine (3.8 compared with 2.5 μg mL−1) and lower distribution half-lives (3.3 compared with 5.9 min) and central compartment volumes of distribution (1.5 compared with 2.1 L kg−1) compared with saline infusion. Benzoylecgonine formation was significantly reduced in rats receiving catecholamines whereas the elimination half-lives (26.3 compared with 25.0 min) and systemic clearances (146 compared with 146 mL kg−1 min−1) were not different. Continuous cocaine infusion (after an initial loading infusion) resulted in the doubling of plasma cocaine levels in rats receiving catecholamines compared with the control group.
These data indicate that elevated plasma catecholamines have significant effects on cocaine pharmacokinetics. This might serve to explain the enhanced toxicity from concomitant cocaine and catecholamine infusion demonstrated in previous experiments.
[3H]AL-5848 ([3H]9β-(+)-Fluprostenol). Carboxylic Acid of Travoprost (AL-6221), a Novel FP Prostaglandin o study the Pharmacology and Autoradiographic Localization of the FP Receptor
Authors: Sharif N A , Davis T L , Williams G W 
Published: July 2003

Abstract
AL-5848 (5Z,13E)-(9 S,11R,15S)-9,11,15-trihydroxy-5,13-prostadienoic acid) is the carboxylic acid of travoprost (AL-6221), a single (+)-isomer of (±)-fluprostenol, an FP-class prostaglandin agonist which lowers intraocular pressure. We have prepared a radioligand from this selective prostaglandin and demonstrated its utility for studying the pharmacology and autoradiographic location of the FP-receptor. Specific [3H]AL-5848 binding (84% of total) was linearly related to bovine corpus luteum tissue concentration and reached equilibrium within 275 min at 23°C. Scatchard analysis of saturation isotherms indicated interaction of [3H]AL-5848 with a single class of high-affinity (dissociation constant, Kd, = 33.8 ± 2.9 nM, n = 4) and saturable (Bmax = 37.3 ± 3.0 pmol (g wet weight tissue)−1) FP receptor-binding sites in bovine corpus luteum. Specific [3H]AL-5848 binding was potently inhibited by the FP-receptor ligands 16-phenoxyPGF2α (inhibition constant Ki = 17.3 nM); cloprostenol (Ki = 56.8 nM); 17-phenyl PGF2α (Ki = 87.0 nM); AL-5848 (Ki = 52.1 nM); PGF2α (Ki = 195 nM); PHXA85 (Ki = 223 nM); (n = 3–11) but very weakly by PGD2, ZK118182, BW245C, PGE2, PGI2 and U-46619. The pharmacology of specific [3H]AL-5848 binding correlated well with the pharmacology of [3H]PGF2α binding in the bovine corpus luteum preparation (r = 0–98, n = 14, P &lt; 0.0001) and also with functional responses in Swiss 3T3 and rat vascular smooth muscle cells (A7r5) (r = 0.96) expressing FP receptors. Autoradiographic studies revealed high levels of specific FP-receptor binding with [3H]AL-5848 on granulosa cells in the bovine corpus luteum sections, and on longitudinal ciliary muscle, the ciliary process, the iris sphincter and the retina in eye sections from man.
These studies show [3H]AL-5848 to be a high-affinity agonist radioligand capable of selectively labelling the FP prostaglandin receptor.
Thromboxane A2 Receptor Antagonism in Man and Rat by a Sulphonylcyanoguanidine (BM-144) and a Sulphonylurea (BM-500)
Authors: Masereel B , Damas J , Fontaine J , Lembege M , Lacan F , Nuhrich A , Delarge J , Pochet L , Dogne J M 
Published: July 2003

Abstract
Torasemide, a loop diuretic, has been reported to relax dog coronary artery precontracted by thromboxane A2 (TXA2), an endogenous prostanoid involved in cardiovascular and pulmonary diseases. N-cyano-N′-{[4-(3′-methylphenylamino)pyrid-3-yl]sulphonyl}homopiperidinoamidine (BM-144) and N-isopropyl-N′-[5-nitro-2-(3′-methylphenylamino)-benzenesulphonyl]urea (BM-500), chemically related to torasemide, have been examined for their TXA2 antagonism.
The affinity (IC50, the concentration resulting in 50% inhibition) of BM-144 and BM-500 for the TXA2 receptor of washed platelets from man was 0.28 and 0.079 μM, respectively. This is better than for sulotroban (IC50 = 0.93 μM) but less than for SQ-29548 (IC50 = 0.021 μM), two TXA2 antagonists used as reference. The aggregation of platelets from man induced by arachidonic acid was prevented by BM-144 (IC50 = 9.0 μM) and by BM-500 (IC50 = 14.2 μM). Similar results were obtained by use of U-46619, a TXA agonist, as aggregating agent (BM-144, IC50 = 12.9 and BM-500, IC50 = 9.9 μM). The contracting effect of U-46619 on rat stomach strip was abolished by BM-144 (IC50 = 1.01 μM) and BM-500 (IC50 = 2–54 μM). Both drugs (BM-144: IC50 = 0.12 and BM-500: IC50 = 0.19 μM) also relaxed rat aorta precontracted by U-46619; both were more potent than sulotroban (IC50 = 1.62 μM). The two torasemide derivatives (100 μM) did not significantly affect the myo-stimulating effect of some prostaglandins (PGE2, PGI2, PGF2α) or aorta contraction elicited by KCl (30 mM). They did not modify rat diuresis after administration of a 30-mg kg−1 dose.
In conclusion, BM-144 and BM-500 can be regarded as novel non-carboxylic TXA2 receptor antagonists and offer a novel template for the design of more potent molecules.
Anti-inflammatory Profile of N-Phenylpyrazole Arylhydrazone Derivatives in Rats
Authors: Barja-Fidalgo Christina , Fierro Iolandda Margherita , Lima Aline C Brando , Da Silva Emerson Teixeira , Câmara Celso De Amorim , Barreiro Eliezer J 
Published: July 2003

Abstract
A series of synthetic N-phenylpyrazole arylhydrazone compounds, rationally designed as mixed-hybrid isosteres of two known inhibitors of prostaglandin synthase and 5-lipoxygenase enzymes, BW-755c and CBS-1108, has been investigated for anti-inflammatory activity in the carrageenan-induced pleurisy model in rats. The compounds have different oxygenated substituent groups in the aryl group of the hydrazone framework to ensure a different range of redox properties. A new arylhydrazone derivative, 2,6-di-tert-butyl-4-(4-nitro-3-methyl-N-phenylpyrazol-5-yl-hydrazonomethyl)phenol, was also synthesized and tested for anti-inflammatory activity.
Although all the compounds significantly inhibited (by 30–90%) neutrophil accumulation in the pleural cavity, there was great variability in the anti-oedematogenic effect of the compounds (3–96%). 5-(4′-Hydroxy-3′-methoxybenzylidene)hydrazone-3-methyl-4-nitrophenylpyrazole was the most active compound in this series; it had a remarkable antiinflammatory profile, almost blocking both assays. In contrast, the compound with a 2,6-di-tert-butylated hydroxybenzene ring on the hydrazone group inhibited neutrophil migration only.
These results will be useful for further structure-activity relationship studies devoted to improving the dual prostaglandin synthase-5-lipoxygenase activity of these derivatives and determining the minimum structural requirements necessary for this activity.
Effect of Caffeine on Ibuprofen-induced Gastric Mucosal Damage in Rats
Authors: Koyama Rika , Kataoka Hirofumi , Tanaka Yoshiyuki , Nakatsugi Seiichi , Furukawa Masumi 
Published: July 2003

Abstract
During investigations on the effect of caffeine on ibuprofen-induced gastric mucosal lesions in rats, we have found that caffeine (p.o.) inhibits the development of ibuprofen-induced gastric lesions in a dose-dependent manner (ED50 18.4mg kg−1). To investigate this protective effect of caffeine, we have studied the effect of caffeine on HCl-ethanol-induced gastric mucosal lesions with or without indomethacin pretreatment.
Caffeine inhibited the development of HCl-ethanol-induced gastric lesions with and without indomethacin pretreatment. These results indicate that caffeine did not act as a mild irritant but, on the contrary, had protective effects. We measured the gastric mucosal prostaglandin E2 (PGE2) concentrations and gastric mucosal blood flow, as representative protective factors for gastric mucosa. Caffeine did not affect the gastric mucosal PGE2 concentrations 4 h after administration of ibuprofen. However, topical administration of caffeine resulted in an increase in gastric mucosal blood flow, as measured by laser Doppler flowmetry. We investigated the gastric acid secretion and gastric mucosal myeloperoxidase activity as representative aggressive factors for gastric mucosa. When caffeine was administered intraduodenally in pylorus-ligated rats, gastric acid secretion decreased in a dose-dependent manner, with an ED50 of 44.9mg kg−1. Caffeine decreased ibuprofen-induced gastric myeloperoxidase activity in a dose-dependent manner, with an ED50 of 9.1mg kg−1.
These findings indicate that caffeine, at least in rats, may inhibit the development of acute gastric mucosal injury. The mechanisms underlying the protective actions of caffeine are unclear, but may be related in part to an increase in gastric mucosal blood flow and suppression of neutrophil activation.
The Therapeutic Effect of Proton Pump Inhibitors on Helicobacter pylori-positive Gastric Ulcers
Authors: Sasakii M , Joh T , Yokoyama Y , Seno K , Tsuchida K , Kurokawa T , Itoh M 
Published: July 2003

Abstract
The aim of the present study was to elucidate the risk factors that could delay gastric ulcer healing when either a proton pump inhibitor or an H2-receptor antagonist is used for gastric ulcer treatment.
Endoscopically-diagnosed gastric ulcer patients (216 men and 96 women, mean age: 57 ± 13 years) were investigated. All patients were consecutively recruited and randomly assigned to receive H2-receptor antagonist (n = 196) or proton pump inhibitor (n = 116) treatment for eight weeks. Chi-squared tests and multivariate analysis to determine factors influencing ulcer healing were used to analyse the patients profiles, endoscopic findings, and Helicobacter pylori-infection status.
In the H2-receptor antagonist group, the most important risk factor was a large ulcer size (&gt; 2 cm diam.), followed by a linear shape of the ulcer, undermining tendency of ulcer, previous history of gastric ulcer, and H. pylori infection. In the proton pump inhibitor group, linear shape of the ulcer was the only significant risk factor for slow ulcer healing; other factors, including H. pylori infection, were insignificant.
These results indicate that ulcer morphology may be the most important information for predicting ulcer healing, and that H. pylori infection does not delay gastric ulcer healing when proton pump inhibitor treatment is used.
Possible Involvement of Ca2+ Entry and its Pharmacological Characteristics Responsible for Endothelium-dependent, NO-mediated Relaxation Induced by Thapsigargin in Guinea-pig Aorta
Authors: Taniguchi Haruyori , Hirano Haruko , Tanaka Yoshio , Tanaka Hikaru , Shigenobu Koki 
Published: July 2003

Abstract
Thapsigargin, a specific inhibitor of Ca2+ -pump Ca2+-ATPase in the sarcoplasmic/endoplasmic reticulum (SR/ER), produces an endothelium-dependent vascular relaxation. In the present study, pharmacological features of thapsigargin-induced endothelium-dependent relaxation were functionally characterized in the isolated guinea-pig aorta especially focusing on the Ca2+ mobilization mechanisms in endothelial cells.
Thapsigargin-induced endothelium-dependent vascular relaxation was markedly suppressed by NG-nitro-L-arginine (L-NNA) and calmidazolium, suggesting that the vascular relaxation to thapsigargin is largely attributable to endothelium-derived nitric oxide (NO) produced as a result of the activation of Ca2+, calmodulin-dependent NO synthase (NOS). Removal of Ca2+ from the external solution abolished the endothelium-dependent relaxation of guinea-pig aorta in response to thapsigargin. Thapsigargin-induced endothelium-dependent relaxation was inhibited more strongly compared with the endothelium-independent relaxation to an NO donor, SIN-1 (3-(4-morpholinyl)-sydnonimine), when the artery preparation was preconstricted with a high concentration (80 mM) of KCl instead of agonistic stimulation. Endothelium-dependent relaxation induced by thapsigargin was not affected by diltiazem, a blocker of L-type voltage-gated Ca2+ channels. SK&F96365 (1-β-[3-(4-methoxyphenyl)propoxy]-4-methoxyphenethyl]-1 H-imidazole) and Ni2+, both of which block capacitative Ca2+ entry, did not show any appreciable inhibitory effects on the endothelium-dependent relaxation to thapsigargin.
These findings suggest that in guinea-pig aorta, endothelium-dependent NO-mediated relaxation induced by thapsigargin is preceded by the increase in the cytosolic free Ca2+ concentrations ([Ca2+]cyt) following the depletion of stored Ca2+ in thapsigargin-sensitive store sites in endothelial cells. Although the increase in [Ca2+]cyt responsible for the activation of endothelium NOS leading to thapsigargin-induced vascular relaxation may be ascribed to the capacitative Ca2+ entry from extracellular space, the Ca2+ entry mechanism stimulated with thapsigargin is deficient in sensitivity to SK&F96365 and Ni2+ in the endothelium of guinea-pig aorta.
A Mild Transient Decrease of Peripheral Red Blood Cell Counts Induced by a Suprapharmacological Dose of Pegylated Human Megakaryocyte Growth and Development Factor in Rats
Authors: Harada Katsuhiko , Ide Youichi , Tazunoki Yoshiko , Imai Atsuko , Yanagida Makoto , Kikuchi Yasuko , Imai Atsushi , Ishii Hiromo , Kawahara Jun-Ichi , Izumi Hideakira , Kusaka Masaru , Tokiwa Tomonobu 
Published: July 2003

Abstract
Previous studies have shown that pegylated recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF) at suprapharmacological dose induces a mild transient decrease of red blood cell counts according to thrombopoiesis in normal mice. To unravel the mechanism underlying this mild transient decrease of red blood cells, we have studied the effect of PEG-rHuMGDF on the circulating plasma and blood volume, and the serum biochemical parameters of anaemia and splenectomy. Also, we have performed histological studies of the bone marrow and the spleen of PEG-rHuMGDF-treated rats.
PEG-rHuMGDF (300 μg kg−1) or vehicle was subcutaneously administered to rats once a day for up to five days. From day 6 after the start of PEG-rHuMGDF administration, the platelet counts and plateletcrit levels were significantly increased, reaching peak values on day 10, and recovering to normal by day 20. The red blood cell counts and the haematocrit levels were significantly decreased on day 6 to 13. The decreases in red blood cell levels and haematocrit produced by PEG-rHuMGDF treatment were mild and had recovered by day 15. The plasma and blood volumes were significantly increased on day 10 in PEG-rHuMGDF-treated rats. No alteration of the serum biochemical parameters for anaemia, iron or total bilirubin, were observed on day 10. The histological examination on day 10 revealed a marked increase in megakaryocytes and a slight decrease in erythropoiesis in the bone marrow of rats that received PEG-rHuMGDF (300 μg kg−1). There was also a slight increase in splenic megakaryocytes and erythropoiesis. The decrease of red blood cells by PEG-rHuMGDF was not affected by splenectomy.
These results suggest that the mild transient decrease of red blood cells induced by PEG-rHuMGDF treatment for up to five days is based mainly on the increases in the plasma and blood volume. These events are secondary changes due to the regulation of the excess production of megakaryocytes in the marrow and the peripheral platelets.
Choline Uptake by Mouse Brain Capillary Endothelial Cells in Culture
Authors: Sawada Naoyuki , Takanaga Hitomi , Matsuo Hirotami , Naito Mikihiko , Tsuruo Takashi , Sawada Yasufumi 
Published: July 2003

Abstract
Choline, a precursor of the neurotransmitter acetylcholine, is synthesized in only small amounts in the brain, so the choline concentration in the brain may vary depending on the plasma concentration and the transport rate across the blood-brain barrier. To elucidate the transport mechanism of choline, we carried out uptake experiments with mouse brain capillary endothelial cells in culture (MBEC4).
[3H]Choline uptake was linear for up to 5min. An examination of the concentration dependence of [3H]choline uptake revealed the operation of both saturable (Jmax = 423 ± 27pmol min−1 (mg protein)−1 and Kt = 20.0 ± 3.1 μM) and non-saturable (kd = 1.23 ± 0.045 μL min−1 (mg protein)−1) processes. The saturable process was independent of Na+ and pH, but was dependent on membrane potential as a driving force. Various basic drugs and endogenous substances, including substrates and inhibitors of the organic cation transporter, significantly inhibited the [3H]choline uptake.
These data suggest that choline was taken up into the endothelial cells via two routes and that a membrane potential-dependent carrier-mediated transport system may participate in choline transport across the blood-brain barrier.