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At least 1,189 records · Page 66Linked to original sources
PubMed2006

Embolization of experimental wide-necked aneurysms with iodine-containing polyvinyl alcohol solubilized in a low-angiotoxicity solvent.

BACKGROUND AND PURPOSE: To evaluate the ready-to-use iodine-containing polyvinyl alcohol (I-PVA) dissolved in the low angiotoxic solvent N-methyl pyrrolidone (NMP) for embolization of porcine wide-necked aneurysms. METHODS: Fourteen broad-based carotid sidewall aneurysms were surgically constructed in 7 swine. I-PVA (40%) in NMP was injected under temporary balloon occlusion bridging the aneurysm neck. After 4 weeks, follow-up angiography, multisection CT angiography (MSCTA), and 3T MR imaging including MR angiography (MRA) sequences were performed. Afterward, harvested aneurysms were investigated histopathologically. RESULTS: The liquid embolic was well visible under fluoroscopy and displayed a favorable precipitation pattern, allowing for controlled polymer delivery. Ten aneurysms (71%) were initially completely occluded, whereas in 1 aneurysm, a minimal polymer leakage was observed. The other 4 aneurysms (29%) were almost completely occluded. One animal suffered a lethal rebleeding from the anastomosis after uneventful embolization. Aneurysms embolized with I-PVA could be discriminated well from the parent artery without beam-hardening artifacts on MSCTA, and no susceptibility artifacts were encountered on MR imaging. Histologic examination revealed all aneurysms covered with a membrane of fibroblasts and an endothelial cell layer while a moderate intraaneurysmal inflammatory response to the polymer was observed. CONCLUSION: I-PVA dissolved in NMP has proved its effectiveness for the embolization of experimental wide-necked aneurysms. This precipitating liquid embolic offers several interesting features in that it needs no preparation before use and no radiopaque admixtures, the latter allowing for artifact-free evaluation of treated aneurysms with MSCTA and MRA. Moreover, it uses NMP as a solvent, which has only a low angiotoxicity.

Animals↗
PubMed2006

Organic solvents as vehicles for precipitating liquid embolics: a comparative angiotoxicity study with superselective injections of swine rete mirabile.

BACKGROUND AND PURPOSE: The organic solvent dimethyl-sulfoxide (DMSO), as a commonly used vehicle for nonadhesive liquid embolics, is not devoid of local angiotoxic effects. We compared microvascular toxicities of superselective infusions of DMSO with potentially more compatible solvents in swine rete mirabile. METHODS: Fourteen swine underwent angiography for superselective catheterization of 28 arteries of the rete while electrocardiography and intra-arterial pressure were continuously monitored. The investigated solvents were DMSO, dimethyl isosorbide (DMI), ethyl lactate, glycofurol 75, N-methyl pyrrolidone (NMP), and solketal. Control infusion of saline ruled out catheter induced vasospasm in all cases. Each artery of the rete was infused only once with 0.8 mL of one of the solvents over 60 seconds. Acute angiographic and hemodynamic consequences were evaluated. Blood samples were assessed for signs of intravascular hemolysis. Brains and retia were harvested for gross and histopathologic investigation. RESULTS: On the basis of the angiographic data, DMSO induced the most pronounced vasospasm with the longest recovery period of all solvents investigated. Ethyl lactate, glycofurol 75, and solketal elicited less severe vasospasms and accordingly resolved much more quickly. DMI and NMP induced only minimal vasospasms with comparably short duration. No solvent caused significant hemodynamic alterations or hemolysis. Gross inspection of brains showed no abnormalities, whereas histopathologic examination revealed mostly nonspecific findings. One rete exposed to solketal displayed possible causal histotoxic changes. CONCLUSION: DMI and NMP produced far less vasospasm than DMSO. No changes in hemodynamic or hemolytic parameters and no histopathologic findings were observed with infusion of these solvents.

Alkenes↗
PubMed2006

Formulation of tablets from the crude extract of Rhinacanthus nasutus (Thai local plant) against Aedes aegypti and Culex quinquefasciatus larvae: a preliminary study.

Dried root powder of Rhinacanthus nasutus, Thong Phan Chang (Thai name) were extracted with methanol (MeOH) in a Soxhlet apparatus and made into 2 formulations of tablet containing the extract at 5% and 10% concentration. Due to the viscous and poor flow properties of the crude MeOH extract obtained, a wet granulation method was conducted in developing the tablets. Lactose was used as a filler. Polyvinyl pyrrolidone (PVP) K30 (15% w/w solution in alcohol) was used as the binding agent, while stearic acid (2% w/w) was used as a lubricant. Both formulas of prepared tablets had a smooth shiny surface with a round shape. Other physical properties of the tablets, such as weight variation, friability and disintegration time, met the requirements of the USP XX standard. The mosquito larvicidal activity of prepared tablets containing 5% and 10% R. nasutus extract against Aedes aegypti were not significantly different from each other (p > 0.05), with 48-hour LC50 values of 13.6 and 14.2 mg/I for the 5% and 10% tablets, respectively, while their activities against Culex quinquefasciatus were similar (p > 0.05) with LC50 values of 18.7 and 17.3, respectively. The larvicidal activity levels against Ae. aegypti and Cx. quinquefasciatus were also not significantly different from each other (p > 0.05). No larval mortality was observed in the two control groups: lactose solution and dechlorinated water. Toxicity to female and male fish (Poecilia reticulata) was tested with the prepared tablets. The toxicity of tablets containing 5% and 10% extracts were not significantly different from each other for the P. reticulata females with 48-hour LC50 values of 105.2 and 110.8 mg/I, respectively, and for P. reticulata males with LC50 values of 99.1 and 103.4 mg/I, respectively. Female and male P. reticulata were sensitive to the same dose of the extract. No fish died in the two control groups, with lactose solution and dechlorinated water. Acute-toxicity bioassay with fish showed that with an exposure of 48 hours the LC50 values of the tablets containing 5% and 10% were 5- to 10-fold higher than the LC50 of R. nasutus against mosquito larvae. These prepared tablets could possibly used to control mosquito vectors and be introduced into the mosquito control program.

Acanthaceae↗
PubMed1975

Effect of Clostridium perfringens epsilon toxin on the blood brain barrier of mice.

It was shown that Clostridium perfringens epsilon toxin has the effect of allowing the passage of 125I polyvinyl-pyrrolidone and 125I human serum albumin into mouse brain. These substances did not enter the brains of normal control mice. The passage of albumin into the brains of mice poisoned with epsilon toxin was extremely rapid. When large doses of toxin (+/-4 000 MLD) were given death ensued within 2-3 min at which stage 1,5% of the injected albumin had already entered the brain. In cases where smaller doses were given and the time interval between injection and death was longer the figure was increased to 2-2 1/2% of the injected plasma albumin.

Animals↗
PubMedDate not supplied

[Impregnation and liberation of nicotine with hydrogen copolymer discs].

Reticulated copolymers with products N-vinyl-2 pyrrolidone (NVP), hydroxy-2 ethyl (HEMA) and methyl methacrylate (MMA) were realized in disc form. Nicotine was used as active principle. On these discs the following study was carried out: permeation, percentage of liquid absorbed, texture, as well as nicotine release kinetics. A 2-variable (NVP and HEMA/MMA), 5-level experimental plan has enabled the outlining of the significant differences on the action of these parameters. The release kinetics show particularly that these discs behave as forms of prolonged released and that the released quantities are sufficient to envisage the use of these reticulated copolymers within the framework of a transdermal system.

Administration, Cutaneous↗
PubMedDate not supplied

HBTU activation for automated Fmoc solid-phase peptide synthesis.

Excellent results have been obtained for the Fmoc solid-phase syntheses of peptides using the activating reagent 2-(1H-benzotriazol-1-yl)-1,1,3,3,-tetramethyluronium hexafluorophosphate (HBTU). Activation occurs very rapidly in N,N-dimethylformamide and N-methyl-pyrrolidone, optimal solvents for peptide-resin solvation. It has been observed that complete coupling reactions occur in only 10-30 min. Residues such as Arg, Ile, Leu and Val, which often require double coupling by other activation methods, react with high efficiency by single coupling when HBTU is used. The Fmoc/HBTU chemistry has recently been applied to the peptide synthesizers. The incorporation of trityl side-chain protection for Fmoc-Asn and Fmoc-Gln further enhances coupling efficiencies in difficult sequences.

Amino Acid Sequence↗
PubMed1991

Effects of chloroquine on lysosomes and endocytosis by liver cells in vivo.

1. Chloroquine accumulation in rat liver after a single and repeated drug administration and lysosomal changes resembling some symptoms of lysosomal storage diseases were observed. 2. Repeated chloroquine treatment of rats resulted in increased activity of liver lysosomal enzymes acid phosphatase and beta-galactosidase and a significant enhancement of the activities of cathepsin D and cysteine proteinases were found. 3. No changes in the activity of liver macrophages (as assessed by the colloidal carbon clearance test) or in fluid-phase endocytosis of the marker 125I-polyvinyl-pyrrolidone by hepatocytes in vivo were found.

Acid Phosphatase↗
PubMedDate not supplied

Action of metadoxine on isolated human and rat alcohol and aldehyde dehydrogenases. Effect on enzymes in chronic ethanol-fed rats.

Metadoxine (pyridoxine-pyrrolidone carboxylate) has been reported to accelerate ethanol metabolism. In the present work we have investigated the effect of metadoxine on the activities of isolated alcohol and aldehyde dehydrogenases from rat and man, and on the activity of these enzymes in chronic ethanol-fed rats. Our results indicate that in vitro metadoxine does not activate any of the enzymatic forms of alcohol dehydrogenase (classes I and II) or aldehyde dehydrogenase (low-Km and high-Km, cytosolic and mitochondrial). At concentrations higher than 0.1 mM, metadoxine inhibits rat class II alcohol dehydrogenase, although this would probably not affect the physiological ethanol metabolism. Chronic ethanol intake for 5 weeks results in a 25% decrease of rat hepatic alcohol dehydrogenase (class I) activity as compared with the pair-fed controls. The simultaneous treatment with metadoxine prevents activity loss, suggesting that the positive effect of metadoxine on ethanol metabolism can be explained by the maintenance of normal levels of alcohol dehydrogenase during chronic ethanol intake. No specific effect of chronic exposure to ethanol or to metadoxine was detected on rat aldehyde dehydrogenase activity.

Alcohol Dehydrogenase↗
PubMedDate not supplied

Pharmacokinetics of disopyramide in the dog. Importance of mono-N-dealkylated metabolite kinetics in assessing pharmacokinetic modeling of the parent drug.

The antiarrhythmic drug disopyramide (DP) is metabolized to the mono-N-dealkylated compound (MND) and to the pyrrolidone derivative (PYR). This study examines the detailed pharmacokinetic characteristics of DP and MND when given simultaneously or separately to dogs. DP and MND were both relatively well absorbed and showed similar pharmacokinetic characteristics. However, the amount of PYR relative to MND as judged by the area under the plasma concentration-time curves (AUC) following oral or iv administration was much greater with DP than with MND. These findings were also supported by the urinary excretion values where the PYR/MND ratio with DP was much greater than with the MND administration. For an explanation of this phenomenon, plasma concentration-time curves for DP, MND, and PYR were simultaneously analyzed assuming various pharmacokinetic models. The plasma levels of these compounds were best described when nonlinear kinetics were assumed for conversion of MND to PYR.

Absorption↗
PubMed1991

Oral magnesium successfully relieves premenstrual mood changes.

Reduced magnesium (Mg) levels have been reported in women affected by premenstrual syndrome (PMS). To evaluate the effects of an oral Mg preparation on premenstrual symptoms, we studied, by a double-blind, randomized design, 32 women (24-39 years old) with PMS confirmed by the Moos Menstrual Distress Questionnaire. After 2 months of baseline recording, the subjects were randomly assigned to placebo or Mg for two cycles. In the next two cycles, both groups received Mg. Magnesium pyrrolidone carboxylic acid (360 mg Mg) or placebo was administered three times a day, from the 15th day of the menstrual cycle to the onset of menstrual flow. Blood samples for Mg measurement were drawn premenstrually, during the baseline period, and in the second and fourth months of treatment. The Menstrual Distress Questionnaire score of the cluster "pain" was significantly reduced during the second month in both groups, whereas Mg treatment significantly affected both the total Menstrual Distress Questionnaire score and the cluster "negative affect." In the second month, the women assigned to treatment showed a significant increase in Mg in lymphocytes and polymorphonuclear cells, whereas no changes were observed in plasma and erythrocytes. These data indicate that Mg supplementation could represent an effective treatment of premenstrual symptoms related to mood changes.

Administration, Oral↗
PubMed1990

Noninvasive transdermal chemical collection. I. In vitro adsorption characteristics of gel/charcoal matrices.

We characterized in vitro adsorption of representative chemicals in candidate gel/charcoal matrices being investigated for use in noninvasive transdermal chemical collection. Binding properties of three model compounds of widely varying water and lipid solubilities (theophylline, methotrexate, and parathion) were studied in hydrophilic (agarose, or polyvinyl alcohol/polyvinyl pyrrolidone) and lipophilic (silicone) gel/charcoal compositions. Analysis of adsorption isotherms indicate that agarose is the superior gel selection for hydrophilic compounds such as theophylline and methotrexate (greater than 90% uptake for each), and that a silicone lipogel allows for greatest lipophilic (parathion) adsorption (greater than 95% uptake).

Absorption↗
PubMedDate not supplied

Antibody responses to thymic independent antigens in the peripheral and mesenteric lymph nodes of mice.

Differentiation of B lymphocytes from various peripheral lymph nodes (PLN) of mice was studied in the in vitro and in vivo conditions. Subcutaneous (SC) immunization in the foot pads with thymic independent (TI)-2 antigens such as polyvinyl pyrrolidone (PVP), R36A, and Trinitrophenyl (TNP)-Dextran failed to elicit plaque forming cell (PFC) responses from the draining popliteal and inguinal lymph nodes, whereas the splenic B cells of these animals exhibited good PFC response. Injection of unconjugated Brucella abortus (BA) along with TNP-Dextran was able to induce anti-TNP PFC formation from the draining lymph node B cells. However, PVP + BA or R36A + BA failed to stimulate such antigen specific B cell responses from the lymph nodes. Since TI antigens are metabolized slowly because of their long repeating subunits, we measured antibody responses up to 8 weeks after SC immunization with TNP-Ficoll and failed to observe any anti-TNP IgM PFC in the lymph nodes. TNP-Ficoll, in contrast to TI-1 antigen TNP-BA, did not induce IgG PFC response in the draining lymph node cells. In in vitro cultures, TNP-Ficoll induced the B cell differentiation from mesenteric lymph node (MLN) cells but not from the PLN cells. This activation of MLN B cells with TNP-Ficoll was limited to normal DBA/2J mice and was absent in the MLN cells of X-linked immune defective CBA/N mice. Finally, there was good antibody response from the inguinal and lumbar lymph node cells after an intraperitoneal immunization with TNP-BA but not with TNP-Ficoll.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

[Synthesis of new fluorogenic substrates derivated of 7-amino-4-trifluoromethylcoumarin. Detection of gram-negative bacteria, Streptococci group A and Enterococci].

The synthesis of substrates having 7-amino 4-trifluoromethyl coumarin as fluorogenic reagent is described. The first group is performed from L-alanine derivative in order to investigate L-alanine aminopeptidase activity for the detection of Gram-negative bacteria. The second group is synthesized from the L-pyrrolidon carboxylic acid. It allows us to detect the PYRase activity of group A Streptococci and Enterococci. These substrates are evaluated with the N-protected form and the amino free one.

Aminopeptidases↗
PubMed1990

Transdermal absorption of radioprotectors in the rat using permeation-enhancing vehicles.

Topical radioprotection of rat skin with WR-2721 has not been effective presumably because the drug does not cross the stratum corneum to reach the epidermis and dermis. Earlier, we showed in the mouse that WR-2721 and cysteine dissolved in permeation-enhancing vehicles passed through the skin more readily than when in water. However, the most effective vehicles in the mouse were not necessarily as effective in the rat. Here we report that the most effective transport vehicles in the rat were (1) water with WR-2721, (2) water and dimethylformamide (DMF) with cysteine, and (3) water and DMF with prostaglandin E2 (PGE2). Pretreatment of the skin with dimethylsulfoxide (DMSO) further improved the transfer of the radioprotectors across the skin in most cases. After pretreatment with DMSO, the most effective vehicles were (1) water for WR-2721, (2) water and methyl-2-pyrrolidone (M-2-P) for cysteine, and (3) DMF for PGE2.

Amifostine↗
PubMedDate not supplied

[The composition of amino acid-peptide mixtures obtained during hydrolysis of proteins].

The composition of the amino acid and peptide fraction of the protein hydrolyzate and its dependence upon the spray-drying process at elevated temperatures were investigated by GLC and GLC-MS. Spray-drying leads to decrease in the Glu and Met contents, to transformation of Cys into cystine and to formation of lactames (pyroglutamic acid and pyrrolidone) and diketopiperazines. Some dipeptides, acetylproline, paraffines, fatty acid pyridinecarboxylic and lactic acids, ethylene glycol were identified in the fraction. The incidental occurrence of these compounds should be taken into account when investigating the biological activity of protein hydrolyzates.

Amino Acids↗
PubMed1990

[A polyvinyl alcohol (PVA) hydrogel as a soft contact lens material].

A transparent polyvinyl alcohol (PVA) hydrogel was prepared from a PVA solution in a mixed solvent consisting of water and a water miscible organic solvent by cooling. The physical properties were evaluated in comparison with commercially available soft contact lens materials, such as polyhydroxyethyl methacrylate (PHEMA) and copolymers of methyl methacrylate (MMA) and N-vinyl pyrrolidone (VP). The PVA hydrogel showed higher tensile strength and elongation at break than the other materials, while it had high water content and oxygen permeability the latter being comparable to those of PMMA/VP copolymers. The protein adsorption of the PVA hydrogel was much less than those of the other materials. The PVA hydrogel soft contact lenses were applied on rabbit eyes for 12 weeks. The influence on the cornea was studied by biomicroscopy, ultrasonic corneal pachymetry and histopathological examination. These examinations revealed no abnormal findings in the cornea. These results suggest that the PVA hydrogel may be promising as a new soft contact lens material.

Adsorption↗
PubMed1990

[Bioavailability studies on the preparations of biphenyl dimethyl dicarboxylate(DDB)].

Since the bioavailability of the suspension and the tablet of DDB given orally is only 20-30%, we have prepared four kinds of DDB solid dispersion preparations (DDB pilule I with polyethylene glycol 6000 as the vehicle, DDB pilule II with polyethylene glycol 6000 and absorption accelerator as the vehicle, capsule of DDB-urea fusing mixture and DDB-polyvinyl pyrrolidone coprecipitate), and the bioavailability of these preparations were studied in rabbits, rats and human volunteers by HPLC method. All four preparations showed better absorption than the DDB tablet, and the area under serum DDB concentration-time curve of pilule II was 19 fold that of the tablet in rabbits, meaning that the absorption of pilule II is the best of the four preparations. After administration of the four solid dispersion preparations, the fecal excretion of DDB were all lower than the tablet in both animals and human volunteers. The protective action of pilule II against CCl4 hepatotoxicity was about six times stronger than that of the suspensions. Therefore, there are good reasons to use DDB pilule II instead of the tablets of suspension in the clinic.

Animals↗
PubMed1975

Proton magnetic resonance studies of alpha-keto acids.

Pulsed Fourier transform proton magnetic resonance was used to study alpha-ketoglutaramic, and several other alpha-keto acids in aqueous solutions as a function of pH. Most alpha-keto acids were found to exist in equilibrium with the hydrate (gem-doil). The equilibrium position favors the nonhydrated alphs-keto acid at neutral pH, but at low pH values (below the pKa of the alpha-carboxylic acid group) the hydrate predominates. We found evidence that alpha-ketoglutaric acid exists in a third equilibrium form which is assigned to the lactol. alpha-Ketoglutaramic acid (the alpha-keto acid analog of glutamine) which is known to exist predominantly in a cyclic form at pH 7.0 was shown to exist as a cyclic structure over a wide pH range. However, the cyclic form is an equilibrium mixture of 2-pyrrolidone-5-hydroxy-5-carboxylic and 1-pyrrolin-2-one-5-carboxylic acids.

Deuterium↗