Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Laurates”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 55 records · Page 3Linked to original sources
PubMed2005

Syntheses of new androstane brassinosteroids with 17beta-ester groups--butyrates, heptafluorobutyrates, and laurates.

New androstane brassinosteroids with 17beta-ester groups - butyrates, heptafluorobutyrates, and laurates (4-18) - were prepared. Brassinolide activity was evaluated using both the bean second internode bioassay and the rice lamina inclination test. Brassinosteroid 16 was found to be the most active by the bean second internode bioassay. This activity in the bean second internode bioassay corresponded with the field yield, while the RLIT bioassay does not.

Androstanes↗
PubMedDate not supplied

A thermoresponsive chitosan-NIPAAm/vinyl laurate copolymer vector for gene transfection.

A carboxyl-terminated N-isopropylacrylamide/vinyl laurate (VL) copolymer was prepared and coupled with chitosan (molecular weight = 2000) to produce a chitosan-NIPAAm/VL copolymer (PNVLCS) vector. The aqueous solution of PNVLCS displayed an obvious thermoresponsive behavior with a lower critical solution temperature (LCST) about 26 degrees C. The transmission electron microscopy (TEM) showed that the size of PNVLCS/DNA complexes varied with charge ratios (+/-), and the smaller nanoparticles were formed at higher charge ratios. DLS revealed that the size of complex particles was dependent on temperature. The results of temperature-variable circular dichroism (CD), UV, and electrophoresis retardation indicated that at lower charge ratios, DNA in the complexes assume a B conformation, whereas increasing charge ratios caused B --> C type conformation transformation; the dissociation-formation of PNVLCS/DNA complexes could be tuned by varying temperature: at 37 degrees C, the collapse of PNIPAAm in PNVLCS was favorable for the formation of compact complexes, shielding more DNA from exposure; at 20 degrees C, the hydrated and extended PNIPAAm chains facilitated the unpacking of DNA from PNVLCS, increasing the exposure of DNA. PNVLCS was used to transfer plasmid-encoding beta-galactosidase into C2C12 cells. The level of gene expression could be controlled by varying incubation temperature. The transfection efficiency of PNVLCS was well improved by temporarily reducing culture temperature to 20 degrees C, whereas naked DNA and Lipofectamine 2000 did not demonstrate the characteristics of thermoresponsive gene transfection.

Acetanilides↗
PubMed1993

Use of pyrenemethyl laurate for fluorescence-based determination of lipase activity in intact living lymphoblastoid cells and for the diagnosis of acid lipase deficiency.

Pyrenemethyl laurate (PMLes), a fluorogenic substrate for determining in vitro lipase activity [Nègre, Salvayre, Dagan and Gatt (1989) Biochim. Biophys. Acta 1006, 84-88], has been administered to cultured lymphoblastoid cells from normal subjects and from a patient affected with Wolman disease, which is characterized by a deficiency of lysosomal acid lipase. The intracellular degradation of PMLes was dependent on the mode of administration of the substrate into the cells, and occurred by two separate pathways involving lysosomal and extra-lysosomal hydrolases. PMLes incorporated into LDL was taken up by normal lymphoblastoid cells through the apolipoprotein-B/E-receptor-mediated pathway and degraded in the lysosomal compartment, as suggested by the degradation block in Wolman cells. In contrast, when PMLes dissolved in 2% dimethyl sulphoxide was added directly to the culture medium, its hydrolysis was similar in lymphoblastoid cells from controls and from patients affected with Wolman disease, neutral lipid storage disease or familial hypercholesterolaemia. This suggested that the administered PMLes was degraded by a non-lysosomal enzyme which is not deficient in Wolman cells. This enzyme also differs from the neutral lipase system which is deficient in lymphoblastoid cells from patients with neutral lipid storage disease. When pyrenemethanol was administered directly to the cell culture, it was only poorly acylated and was rapidly released into the culture medium. These results and the fluorescence properties of PMLes ('monomeric' emission in a hydrophobic environment and 'excimeric' emission in a hydrophilic environment) and pyrenemethanol ('monomeric' emission in a hydrophilic environment) allowed us to design a 'direct reading' procedure by monitoring (without any lipid extraction) the fluorescence of intact living cells and that of the culture medium during pulse-chase experiments. This method allowed the direct evaluation of the time course of in situ degradation of PMLes. In pulse-chase experiments with LDL-PMLes, the fluorescence of normal cells decreased relatively rapidly with time whereas the fluorescence of the culture medium increased concomitantly. With Wolman cells, the cellular fluorescence decreased only very slightly, whereas that of the culture medium remained at the basal level; this demonstrates the catabolic block in intact living cells from patients with Wolman disease. In vitro degradation of PMLes indicated the existence of two PMLes-degrading enzymes in lymphoblastoid cell homogenates: one is the acid lipase which is involved in PMLes degradation in the lysosomal compartment (and is deficient in Wolman cells), while the second is a cytoplasmic enzyme (not deficient in Wolman cells).

Biological Transport↗
PubMed2000

AT-1015, a novel serotonin (5-HT)2 receptor antagonist, blocks vascular and platelet 5-HT2A receptors and prevents the laurate-induced peripheral vascular lesion in rats.

The serotonin (5-HT2A) antagonistic activities and the protective effect on laurate-induced peripheral vascular lesions of AT-1015, a novel 5-HT2 receptor antagonist, were investigated. In platelet aggregation, AT-1015 selectively inhibited in vitro 5-HT2A receptor-mediated aggregation, and the activity was almost equivalent to that of ketanserin (5-HT2A/2C receptor antagonist) and 100 times more potent than sarpogrelate (5-HT2A receptor antagonist). AT-1015 also inhibited 5-HT2A receptor-mediated aggregation by oral administration in rat, and the dose required for inhibition was equivalent to ketanserin. In a 5-HT-induced vasoconstriction study in rat, AT-1015 slightly reduced maximal contraction and caused a rightward shift of the concentration-response curve (pKB value, 9.5), which was unlike competitive inhibitors such as ketanserin and sarpogrelate (pA2 value, 9.3 and 8.7, respectively). Moreover, the ex vivo inhibitory activity significantly remained after oral administration (1 mg/kg). In the rat peripheral vascular lesion model, AT-1015 (1 mg/kg, p.o.) effectively prevented progression of peripheral lesions, and it was more potent compared with ketanserin, sarpogrelate, and cilostazol. These results suggest that AT-1015 is a potent 5-HT2A receptor antagonist, and its insurmountable antagonism may be relevant to its therapeutic potential in peripheral vascular disease.

Animals↗
PubMed1992

Ionization of tyrosine residues in human serum albumin and in its complexes with bilirubin and laurate.

Spectrophotometric titration of human serum albumin indicates that ionization of the 18 tyrosine residues takes place between pH 9 and 12.7. A Hill plot indicates that protons dissociate co-operatively from tyrosine residues, in pure albumin between pH 11.0 and 11.4 with a Hill coefficient 1.7, and in the bilirubin-albumin complex between pH 11.2 and 11.7 with a Hill coefficient 1.6. With a stopped-flow technique it is shown that about seven of the tyrosines ionize fast, with rate constants well above 10(2) s-1, when pH is suddenly changed from near neutral to pH 11.76. Further residues ionize slowly, with rate constants around 10(2) s-1 or less. The N-form of albumin (pH 6) contains one more fast ionizing tyrosine than the B-form of albumin (pH 10). Binding of bilirubin or laurate to the albumin molecule (molar ratio 1:1) transforms one to three of the fast ionizing tyrosines to slowly ionizing.

Bilirubin↗
PubMed2004

Effective accumulation of poly(vinylpyrrolidone-co-vinyl laurate) into the spleen.

To optimize polymer-conjugated drugs as a polymeric drug delivery system, it is essential to design polymeric carriers with tissue-specific targeting capacity. Previously, we showed that polyvinylpyrrolidone (PVP) was the most suitable polymeric carrier for prolonging the blood-residency of drugs, and was one of the best parent polymers to design the polymeric carriers with targeting capacity. In this study, we synthesized some hydrophobic PVP derivatives, poly(vinylpyrrolidone-co-styrene) [poly(VP-co-S)] and poly(vinylpyrrolidone-co-vinyl laurate) [poly(VP-co-VL)], and assessed their biopharmaceutical properties after intravenous administration in mice. The elimination of hydrophobic PVP derivatives from blood was the same as PVP, and the plasma half-lives of poly(VP-co-S) were almost similar to that of poly(VP-co-VL). Poly(VP-co-VL) efficiently accumulated in the spleen, whereas poly(VP-co-S) effectively accumulated in the liver. The level of poly(VP-co-VL) in the spleen was about 20 times higher than PVP and poly(VP-co-S). These hydrophobic PVP derivatives did not show any cytotoxicity against endothelial cells in vitro. Thus, poly(VP-co-VL) may be a useful polymeric carrier for drug delivery to the spleen. This study will provide useful information to design optimal polymeric carriers with targeting capacity to the spleen and liver.

Animals↗
PubMed2002

Mechanisms of cytoprotective effect of amino acids on local toxicity caused by sodium laurate, a drug absorption enhancer, in intestinal epithelium.

Several amino acids, including L-glutamine (L-Gln), were found to protect the intestinal epithelial cells from the local toxicity caused by a drug absorption enhancer, sodium laurate (C12), in our previous study. To develop more efficient and safer formulations for enhancing drug absorption, the mechanisms of cytoprotection by amino acids were studied using rats and Caco-2 cells. Four amino acids, including L-Gln, could generally maintain the absorption-promoting action of C12, although taurine tended to attenuate it. Three amino acids, except for L-Gln, significantly suppressed the decrease in the transepithelial electrical resistance caused by C12. Quercetin, an inhibitor for biosynthesis of heat shock protein 70 (HSP70), masked only the protective effect of L-Gln in both rat large intestine and Caco-2 cells. Western blot analysis indicated clearly that HSP70 is induced extensively only by the addition of L-Gln in both rat large-intestinal cells and Caco-2 cells. C12 was found to increase the intracellular concentration of Ca(2+) ([Ca(2+)](i)) remarkably, and amino acids, especially L-arginine, L-methionine, and taurine, significantly attenuated the increase in [Ca(2+)](i) caused by C12. Furthermore, although C12 stimulated the release of histamine, an inflammatory mediator, from rat large-intestinal tissue, amino acids were also found to suppress the release of histamine enhanced by C12. The results in the present study showed that an induction of HSP70, a decrease in [Ca(2+)](i) elevated by C12, and a suppression of histamine release stimulated by C12 should be involved in the mechanisms behind the cytoprotective action of amino acids against the local toxicity caused by C12.

Algorithms↗
PubMed2003

Combinatorial use of sodium laurate with taurine or L-glutamine enhances colonic absorption of rebamipide, poorly absorbable antiulcer drug, without any serious histopathological mucosal damages.

We previously reported that the combinatorial use of sodium laurate (C12) with several amino acids such as taurine (Tau) and L-glutamine (L-Gln) enhanced the colonic absorption of phenol red with attenuating the local toxicity caused by C12. However, even these amino acids could not protect epithelial cells from being damaged if the mucosal damage got worse to the coagulation necrosis by an excessive dose of C12. Comparing C12 with sodium caprate (C10), used in drug products marketed, 100 micromol C10 was needed to exert the similar absorption-enhancement of rebamipide, a poorly absorbable antiulcer drug, to that by 10 micromol C12, and 100 micromol C10 was obviously more toxic to the mucosa than 10 micromol C12. The combinatorial use of C12 with Tau or L-Gln enhanced the colonic absorption of rebamipide four to nine times larger in AUC than the control. Histopathologic studies clearly showed that Tau and L-Gln exerted the cytoprotective action on epithelial cells suffering from slight damages such as shrinkage and exfoliation, more articulately at 6 h than at 1.5 h after dosing. In conclusion, the combinatorial use of C12 with Tau or L-Gln could lead to a novel formulation improving the bioavailability of poorly absorbable drugs without any serious local damages.

Adjuvants, Pharmaceutic↗
PubMed2001

Amino acids protect epithelial cells from local toxicity by absorption enhancer, sodium laurate.

To develop the safe absorption-enhancing formulation attenuating the local toxicity caused by an absorption enhancer, sodium laurate (C12), the effects of amino acids on the local toxicity by C12 were examined in rats. The absorption of phenol red, an unabsorbable marker drug, was significantly enhanced by 10 mM C12 in an in situ colon loop study and the addition of L-glutamine (L-Gln), L-arginine, or L-methionine at 10 mM did not change the promoting effect of C12. However, C12 significantly increased the elution of phospholipids, total protein, and lactate dehydrogenase, which are markers for local toxicity, from colon, but these amino acids attenuated the local toxicity caused by C12 significantly. Transport study using an Ussing-type chamber showed that the permeability of colonic membrane to phenol red was significantly enhanced by C12 and that L-Gln did not decrease the permeability enhanced by C12. Transmucosal electrical resistance was extensively decreased by C12, indicating that C12 could enhance the drug absorption at least partly by expanding the paracellular route. L-Gln significantly, but not completely, recovered resistance lowered by C12. Electrical potential difference was markedly reduced by C12, suggesting that C12 lowered the viability of mucosal cells, but 10 mM L-Gln significantly recovered potential difference almost to the control level. These results suggested the possibility that absorption-enhancing formulation with low local toxicity, which is low enough to be used practically, could be developed by using an amino acid like L-Gln as an ingredient attenuating the local toxicity caused by C12.

Amino Acids↗
PubMed2006

Involvement of intracellular Ca2+ dynamics in cytoprotective action by amino acids and cytotoxicity by sodium laurate, an absorption enhancer.

In our previous studies, taurine (Tau) and L-glutamine protected intestinal epithelial cells from local toxicity caused by sodium laurate (C12), an absorption enhancer, while maintaining sufficient absorption-enhancing effect of C12, and it was suggested that one of the mechanisms behind cytoprotection by amino acids was to prevent intracellular Ca2+ concentration ([Ca2+]i) from increasing. In the present study, we focused on the elucidation of mechanisms by which C12 increases [Ca2+]i and by which amino acids suppress [Ca2+]i by utilizing Caco-2 cells. Removal of extracellular Ca2+ remarkably suppressed the increase of [Ca2+]i by C12. Compound 48/80, an inhibitor of phospholipase C, and verapamil, a Ca2+ channel inhibitor, also significantly prevented [Ca2+]i elevation. These results indicate that C12 augmented [Ca2+]i due to (a) influx of extracellular Ca2+ through Ca2+ channel, (b) release of Ca2+ from the endoplasmic reticulum. Cytoprotective action by amino acids was significantly attenuated by orthovanadate, an inhibitor of plasma membrane Ca2+-ATPase (PMCA), suggesting that amino acids activate PMCA to enhance the efflux of intracellular Ca2+. Furthermore, Tau enhanced the mitochondrial uptake of Ca2+, which could contribute to the decrease in [Ca2+]i. These results clearly show that amino acids protect intestinal epithelial cells from being damaged by modulating intracellular Ca2+ dynamics.

Arginine↗
PubMed1976

Zonal rotor analysis of the subcellular localization of alpha-glycerphosphate dehydrogenase, alpha-naphthyl palmitate and beta-naphthyl laurate hydrolases in the mucosa of the guinea-pig small intestine.

Whole homogenate of guinea-pig small intestine mucosa was analysed by centrifugation in a zonal rotor. The results indicate that FAD-linked alpha-glycerophosphate dehydrogenase is localized in the mitochondria and that NAD-linked alpha-glycerophosphate dehydrogeanse is a soluble phase enzyme. An enzyme hydrolysing alpha-naphthyl palmitate at an acid pH was localized in the lysosomes and was activated by 0.1% Triton X-100 and by freezing and thawing. An alkaline hydrolase acting on beta-naphthyl laurate was localized in the 'microsomes'. The possibility of this enzyme being different from alpha-naphthyl acetate hydrolase is discussed.

Animals↗
PubMed2000

The distribution of caprylate, caprate and laurate in lipids from developing and mature seeds of transgenic Brassica napus L.

The composition and positional distribution of lipids in developing and mature transgenic Brassica napus seeds accumulating up to 7 mol% of caprylate (8:0), 29 mol% caprate (10:0) or 63 mol% of laurate (12:0) were examined. The accumulation of 8:0 and 10:0 resulted from over-expression of the medium-chain-specific thioesterase (Ch FatB2) alone or together with the respective chain-length-specific condensing enzyme (Ch KASIV). Seeds containing high levels of 12:0 were obtained from plants expressing bay thioesterase (BTE) alone or crossed with a line over-expressing the coconut lysophosphatidic acid acyltransferase (LPAAT), an enzyme responsible for the increase in acylation of 12:0 at the sn-2 position. In all instances, 10:0 and 12:0 fatty acids were present in substantial amounts in phosphatidylcholine during seed development with a drastic decrease of 80-90% in mature seeds. At all stages of seed development however, 8:0 was barely detectable in this membrane lipid. Altogether, these results indicate that these transgenic seeds exclude and/or remove the medium-chain fatty acids from their membrane and that this mechanism(s) is more effective with the shorter-chain fatty acids. Furthermore, seeds of 8:0- and 10:0-producing lines had only negligible levels of these fatty acids present in the sn-2 position of the triacylglycerols. In contrast, all 12:0-producing seeds had a substantial amount of this fatty acid in the sn-2 position of the triacylglycerols, suggesting that the endogenous LPAAT is able to acylate 12:0 if no other acyl-CoA species are available.

Brassica↗
PubMed1984

Induction of laurate omega-hydroxylase by di (2-ethylhexyl)phthalate in rat liver microsomes.

Liver microsomes, prepared from rats fed a diet containing di (2-ethylhexyl)phthalate, were observed to hydroxylate lauric acid at carbon 12 at a specific activity 6 times greater than control rats. There was no increase in the specific activity of the laurate 11-hydroxylase. The specific activity of hepatic microsomal NADPH-cytochrome c reductase was increased 2-fold by phthalate feeding, but no effect was observed in the specific contents of cytochromes b5 or P-450. These results indicate that di (2-ethylhexyl)phthalate is similar to the hypolipidemic agent and peroxisomal proliferator , clofibrate, which was previously reported to be a novel inducer of the cytochrome P-450 mediated omega-hydroxylation of fatty acids.

Animals↗
PubMed1987

Induction of peroxisomal fatty acyl-CoA oxidase and microsomal laurate hydroxylase activities by beclobric acid and two metabolites in primary cultures of rat hepatocytes.

Beclobrate [2-(4-[(4-chlorophenyl)methyl]phenoxy)-2-methylbutyric acid ethyl ester], a structural analog of clofibrate, is used clinically as a lipid-lowering agent. Although, like clofibrate, beclobrate produces a profound hepatomegalic response in rodents, no studies of this drug on hepatic peroxisome proliferation have appeared. We have examined, relative to clofibric acid (CPIB), the concentration-dependent effects of beclobric acid (Beclo), the activity moiety of beclobrate, and two oxidized metabolites [a carbinol (M2) and a benzophenone (M3)] on peroxisomal fatty acyl-CoA oxidase (FACO) and microsomal laurate hydroxylase (LH) activities in primary cultures of rat hepatocytes. All compounds induced FACO and LH activities in a concentration-dependent manner after a 72 hr incubation with the cultured cells. Beclo was 4.8- and 6.5-fold more potent than CPIB as an inducer of FACO and LH respectively. M2 and M3 were more potent than Beclo as inducers of FACO and LH. Additionally, all compounds produced significant elevations relative to untreated control cultures in cellular lactate dehydrogenase activity (1.6- to 2.2-fold). We conclude that (1) Beclo is more potent than CPIB as an inducer of peroxisome proliferation-associated enzyme activities; (2) two metabolites of Beclo are more potent than the parent molecule as inducers of these activities and (3) these metabolites may contribute to the lipid-lowering and/or hepatomegalic effects of beclobrate in rats.

Acyl-CoA Oxidase↗
PubMed1988

The importance of threonine-301 from cytochromes P-450 (laurate (omega-1)-hydroxylase and testosterone 16 alpha-hydroxylase) in substrate binding as demonstrated by site-directed mutagenesis.

Threonine-301 from rabbit liver cytochromes P-450 (laurate (omega-1)-hydroxylase and testosterone 16 alpha-hydroxylase) has been replaced by histidine via site-directed mutagenesis. In the oxidized state the mutant P-450s exhibited typical low-spin type absorption spectra of P-450 and their reduced CO complexes showed a Soret peak at 450 nm. However, no spectral change was induced on addition of substrates for their wild-type counterparts. The mutant P-450s were also completely devoid of the hydroxylase activity. These findings suggest that threonine-301, which is highly conserved in P-450s and located at the distal heme surface, plays an important role in substrate binding.

Amino Acid Sequence↗
PubMed2005

A kinetic and thermodynamic study on hydrolysis of sodium laurate in aqueous phase accompanied by transfer into oil phases containing different organic additives (I).

The kinetic and thermodynamic behavior at the interface between an aqueous solution of sodium laurate (NaLA) and various oil phases comprised primarily of benzene (Bz) and/or different organic compounds including amphiphiles has been investigated in regard to the hydrolysis of NaLA accelerated at the interface, transfer of lauric acid (LA) into oil phase and reverse transfer of Bz into aqueous phase in addition to interface tension. The contact of aqueous NaLA solution with the oil phase was found to accompany the mass transfer of LA and simultaneously promote the hydrolysis of NaLA in water phase. Analysis of the change of OH- ion concentration ([OH-]) over time allowed us to treat the events as a first order reaction. From the rate constant data the activation parameters such as the activation enthalpy and entropy, both of which control the transfer of LA molecules, were determined. The parameters were found to depend greatly on varied situations of the oil phase, being clearly able to explain the physicochemical behavior of the interface. Comparing the cases where the oil phase is one of the respective single systems such as Bz, dodecane (C12) and dodecylbenzene (C12Bz), C12Bz resulted in the lowest rate constant. The transfer (or hydrolysis) rate was measured for the amphiphile-added oil systems as a function of amphiphile concentration. When 0.206 M C16OH-Bz came in contact with aqueous phase, emulsion formation at the interface layer was brought about with approximately zero activation enthalpy, leading to facile or spontaneous transfer of LA. In addition, UV absorbance representing the transfer of Bz from the oil phase to the aqueous phase also demonstrated the effects of added amphiphiles on the action of the interface.

Diffusion↗
PubMed2004

Development of suppository formulation safely improving rectal absorption of rebamipide, a poorly absorbable drug, by utilizing sodium laurate and taurine.

To develop the safe formulation that can safely improve bioavailability of poorly absorbable drugs and that is practically available, we prepared the suppositories of rebamipide, a poorly soluble and poorly absorbable antiulcer drug, by employing the combinatorial use of sodium laurate (C12), an absorption enhancer, with taurine (Tau) or L-glutamine (L-Gln), an adjuvant exerting the cytoprotective action. Although the dissolution of rebamipide from fatty base (FB) suppository prepared using Witepsol H-15 was very slow, it was remarkably improved by the addition of C12 and L-Gln or Tau into the suppository. On the other hand, the dissolution of rebamipide from water-soluble base (WB) suppository prepared using polyethylene glycol was very rapid and the addition of adjuvants did not influence its dissolution so much. Rectal absorption of rebamipide examined in rats was remarkably improved by FB suppository containing C12 or both C12 and Tau, while the enhancing effect of C12 was relatively small in the case of WB suppositories. Biochemical and histopathological studies have confirmed that FB suppository containing both C12 and Tau or L-Gln did not cause any serious local damage, while FB suppository containing C12 only caused the erosion and shrinkage for a lot of rectal epithelial cells. In conclusion, FB suppository employing the combinatorial use of C12 with Tau could be a promising formulation that is effective and safe enough for poorly absorbable drugs to be practically administered.

Alanine↗
PubMed2003

Magnetophoretic velocity of microorganic droplets adsorbed by dysprosium(III) laurate in water.

By using an improved apparatus for the observation of magnetophoresis, the magnetophoretic velocity of 2-fluorotoluene droplets including lauric acid was measured in aqueous dysprosium(III) solution. The magnetophoretic velocity of pure 2-fluorotoluene droplets was proportional to the square of the radius. On the other hand, the velocity of the organic droplets including lauric acid in the dysprosium(III) solution showed a deviation from the square radius relationship, more remarkably in smaller droplets than 2 microm in radius. These results indicated that the dysprosium(III)-laurate complex was formed at the liquid-liquid interface. This study is the first report on the detection of the interfacial complex by the magnetophoresis of the microdroplet.

Adsorption↗