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Results 351 - 400 of 1091
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Balboni G - - 2000
In lieu of H-Dmt-Tic-OH, H-Dmt-analogues included 2-amino-3(1H-benzoimidazol-2-yl)-propionic acid, N(Bzl)Gly, L-octahydroindole-2-carboxylic acid, [3S-(3alpha,4abeta, 8abeta)]-decahydro-3-isoquinoline carboxylic acid, benzimidazole-, pyridoindole- or spiroinden-derivatives, or C-terminally modified. L- or D-Ala, Sar, or Pro were spacers between aromatic nuclei. Only H-Dmt-(Xaa-)-pyridoindole exhibited high affinities with delta and mu antagonism. The peptides competed equally against [3H]DPDPE (delta ...
van den Akker J T - - 2000
An important limitation of topical 5-aminolevulinic acid (ALA)-based photodetection and photodynamic therapy is that the amount of the fluorescing and photosensitizing product protoporphyrin IX (PpIX) formed is limited. The reason for this is probably the limited diffusion of ALA through the stratum corneum. A solution to this problem might be ...
Mesenhöller M - - 2000
The aim of this study was to determine the part played by the mitochondrial benzodiazepine receptor in cellular photosensitisation with the protoporphyrin IX precursor, delta-aminolaevulinic acid. Evaluation of the delta-aminolaevulinic acid-concentration dependence and kinetics of fluorescent protoporphyrin IX accumulation in monolayers of rat AR4 2J pancreatoma cells established a basis ...
Gerscher S - - 2000
Our novel approach was to compare the pharmacokinetics of 5-aminolevulinic acid (ALA), ALA-n-butyl and ALA-n-hexylester induced protoporphyrin IX (PpIX), together with the phototoxicity after photodynamic therapy (PDT) in human skin in vivo, using iontophoresis as a dose-control system. A series of four increasing doses of each compound was iontophoresed into ...
Parsch J - - 2000
In vivo levels of enzymatic activity may be increased through either structural or regulatory changes. Here we use Drosophila melanogaster alcohol dehydrogenase (ADH) in an experimental test for selective differences between these two mechanisms. The well-known ADH-Slow (S)/Fast (F) amino acid replacement leads to a twofold increase in activity by ...
Brenner R R - - 2000
Streptozotocin diabetes depresses delta 9, delta 6 and delta 5 fatty acid desaturases, decreasing arachidonic acid and increasing linoleic acid, but also unexpectedly increasing docosahexaenoic acid in the different phospholipids of liver microsomal lipids. 18:0/20:4n-6, 16:0/20:4n-6 and 16:0/18:2n-6 are the predominant phosphatidyl choline (PC) molecular species in control rats, determining ...
Casas A - - 2000
BACKGROUND: The optimal vehicle to ensure adequate penetration of 5-aminolaevulinic acid (ALA) for its use in photodynamic therapy (PDT) of skin lesions has not been determined. OBJECTIVES: We aimed to study the effects of ALA in various vehicle formulations [saline lotion with and without dimethylsulphoxide (DMSO), cream, liposomes and vaseline] ...
Barbe J C - - 2000
Carbonyl compounds play an important role in musts from botrytized grapes. Some of them, such as glyoxal and methylglyoxal, may explain a considerable part of bindable SO(2). Others, such as 2- and 5-oxogluconic acids, produced by gluconic acid oxidation in proportions respectively from 2.5 per 1 play an interesting role ...
Hongcharu W - - 2000
Topical aminolevulinic acid is converted into a potent photosensitizer, protoporphyrin, in human hair follicles and sebaceous glands. Photodynamic therapy with topical aminolevulinic acid was tested for the treatment of acne vulgaris, in an open-label prospective human study. Each of 22 subjects with acne on the back was treated in four ...
Precht D - - 2000
In some countries the content of trans fatty acids (TFA) in margarines has strongly decreased as a result of the continuous discussion on their disadvantages regarding aspects of nutritional physiology. However, still in 1994 almost 1/3 of total fatty acids in part of German sunflower margarines, shortenings and cooking fats ...
Goese M - - 2000
The lipase inhibitor lipstatin is biosynthesized in Streptomyces toxytricini via condensation of a C(14) precursor and a C(8) precursor, which are both obtained from fatty acid catabolism. To study the mechanism of this reaction in more detail, S. toxytricini was grown in medium containing a mixture of U-(13)C,U-(2)H-lipids and unlabeled ...
Moretti M B - - 2000
In Saccharomyces cerevisiae, as in all eukaryotic organisms, delta-aminolevulinic acid (ALA) is a precursor of porphyrin biosynthesis, a very finely regulated pathway. ALA enters yeast cells through the gamma-aminobutyric acid (GABA) permease Uga4. The incorporation of a metabolite into the cells may be a limiting step for its intracellular metabolization. ...
Wennberg A M - - 2000
Delta-aminolevulinic acid (ALA) is used for photodynamic therapy of basal cell carcinoma (BCC) as it is converted to protoporphyrin IX in tumour tissue. During illumination with 635 nm light a photochemical reaction takes place, singlet oxygen is generated and the tumour destroyed. In this study we used the microdialysis technique ...
Mas E - - 2000
(Z)-11-Hexadecenyl acetate, the main pheromone component of Sesamia nonagrioides sex pheromone, is biosynthesized from palmitic acid by Delta(11)-desaturation followed by reduction and acetylation. Production of (Z)-11-hexadecenyl acetate is regulated by the Pheromone Biosynthesis Activating Neuropeptide (PBAN). Transformation of (Z)-11-hexadecen-1-ol into the corresponding acetate is a target step for PBAN in ...
Velasco L - - 2000
The evaluation of tocochromanols (tocopherols and tocotrienols) in 49 accessions from 21 Orobanche species revealed three well separated groups. The first one, characterized by high gamma-tocotrienol content, included all the accessions of sect. Orobanche. The second one, exhibiting high gamma-tocopherol content, comprised the accessions of O. arenaria Borkh. and O. ...
Boger D L - - 2000
The development of exceptionally potent inhibitors of fatty acid amide hydrolase (FAAH), the enzyme responsible for the degradation of oleamide (an endogenous sleep-inducing lipid), and anandamide (an endogenous ligand for cannabinoid receptors) is detailed. The inhibitors may serve as useful tools to clarify the role of endogenous oleamide and anandamide ...
Jeffes E W EW - - 2000
Actinic keratoses are hyperkeratotic skin lesions that represent focal abnormal proliferation of epidermal keratinocytes. Some actinic keratoses evolve into squamous cell carcinoma of the skin, while others resolve spontaneously. The conversion rate of actinic keratosis to squamous cell carcinoma is not accurately known, but appears to be in the range ...
Casimir JR - - 2000
N-Boc-protected-5-substituted delta-lactams were readily prepared from the corresponding beta 3-amino acids. Alkylation reactions of their Na enolates with various electrophiles proceeded in high yields with high facial selectivity. The structure of the alkylation products was confirmed by single-crystal X-ray analysis. This method provides a fast access to optically active alpha, ...
Garcia S C - - 2000
The first specific precursor of porphyrin biosynthesis is delta-aminolevulinic acid. delta-Aminolevulinic acid enters Saccharomyces cerevisiae cells through the gamma-aminobutyric acid specific permease Uga4p. It was described that this permease is inducible by gamma-aminobutyric acid and its regulation involves several specific and pleiotropic transcriptional factors. However, some studies showed that under ...
Parenti P - - 2000
L-leucine uptake into membrane vesicles from Bombyx mori larval midgut was tested for inhibition by 55 compounds, which included sugars, N-methylated, alpha-, beta-, gamma-, delta-, epsilon-amino acids, primary amines, alpha-amino alcohols, monocarboxylic organic acids and alpha-ketoacids. Based on cis-inhibition experiments performed at the high pH (10.8) characteristic of the midgut ...
Metges C C - - 2000
We present the analysis of the stable carbon isotope compositions of 14 individual N-pivaloyl-isopropyl (NPP) amino acid esters by gas chromatography-combustion isotope ratio mass spectrometry (GC-C-IRMS). The mean reproducibility of derivatization procedure and GC-C-IRMS analysis was 0.45 per thousand (range, 0.12-0.68), whereas the mean analytical error was 0.26 per thousand ...
Kubica Z - - 2000
Easily accessible Ac-(Z)-delta Phe-NHMe was photoisomerized to so far unknown Ac-(E)-delta Phe-NHMe. Some parameters of the process leading to a diastereomeric mixture of ratio 90(Z):10(E) have been tested and the photoisomerization has been carried out on a preparative milligram scale. The isomers were separated via crystallization followed by preparative HPLC.
El-Saht H M - - 2000
Chloroplast development and chlorophyll biosynthesis are co-regulated. Treatment by levulinic acid resulted in a linear relation in both chlorophyll and carotenoid contents, during greening of etiolated French bean leaf discs. Chlorophyll biosynthesis appeared to control that of caroteins. In the presence of levulinic acid; at different levels, photosystem II (PS ...
Hansen Mark R - - 2000
Abstract Pf1 filamentous phage represent a simple versatile method for generating partially ordered macromolecules in solution. The phage allow tunable degrees of alignment of macromolecules under a wide range of temperature and solvent conditions. The negatively charged phage are ideal for aligning negatively charged nucleic acids and these phage-nucleic acid ...
Sajbidor J - - 2000
The effect of methylfenpropidine on growth, lipid contents, sterol and fatty acid composition was investigated in 5 strains of Candida albicans. The sensitivity of the strains decreased in the order: wild strains > erg+ ade nysR > ade nysR erg (defective delta (8-7)-isomerase) > ade nysR erg (defective delta 5-desaturase). ...
Ano A - - 2000
To investigate the effects of levulinic acid (LA) on extracellular 5-aminolevulinic acid (ALA) accumulation, a heterotrophic culture of Chlorella regularis YA-603 in basal medium containing 0 to 60 mM of LA was carried out. It was found that the extracellular and total ALA concentrations increased, while the chlorophyll (CHL) concentration ...
Akagawa M - - 1999
A trifunctional crosslinking amino acid named cyclopentenosine (CP) was isolated from the hydrolysate of bovine nuchal ligament elastin. CP and its derivatives were identified by spectroscopic methods. CP was found to consist of a 2-cyclopenten-1-one structure and its imine-enamine tautomers with enantiomers in H(2)O. A model reaction for the formation ...
Kriegmair M - - 1999
PURPOSE: We determined whether neoplastic disease, which was missed under white light can be found during transurethral resection of bladder cancer by 5-aminolevulinic acid-induced porphyrin fluorescence. MATERIALS AND METHODS: 5-Aminolevulinic acid-induced fluorescence endoscopy was carried out in 328 cases. A 3% 5-aminolevulinic acid solution was instilled intravesically in a mean ...
Silveira M M - - 1999
The bioconversion of glucose and fructose to gluconic acid and sorbitol, respectively, by the enzymes glucose-fructose oxidoreductase (GFOR) and glucono-delta-lactonase (GL), contained in untreated cells of Zymomonas mobilis ATCC 29191, was investigated in batch runs with glucose plus fructose concentrations (S0) varying from 100 to 750 g l-1 in equimolar ...
Takahashi S - - 1999
A mixture of rProROL having the full-length prosequence (97 amino acids) for a recombinant lipase of Rhizopus oryzae (rROL) and r28ROL having 28 amino acids of the same prosequence has been produced as active forms by Saccharomyces cerevisiae [Takahashi et al. (1998) J Ferment Bioeng 86: 164-168]. However, the separation ...
Tolosa I - - 1999
Some applications in the use of compound-specific isotopic analyses (CSIA) for biomarker source elucidation in the marine environment and its potential applications to paleoclimatology are evaluated in the present study. The potential use of the carbon isotope ratios of marine biomarkers as recorders of CO2 levels has been considered. A ...
Lewis S A SA - - 1999
Recently potassium nitrite has been used as an adulterant to interfere with the analysis of 11-nor-delta 9-tetrahydro-cannabinol-9-carboxylic acid (THC-COOH) in urine. A comprehensive study of the THC-COOH and nitrite reaction chemistry and stability under various conditions is presented. Reverse phase high performance liquid chromatography (HPLC) and negative electrospray mass spectrometry ...
Matthan N R - - 1999
Recent findings indicate that certain (t-C18:1 delta 9) but not all (t-C16:1 delta 9 and t-C18:1 delta 11) trans fatty acid isomers influence intestinal lipoprotein secretion. A mechanism is suggested that appears to be sensitive to properties associated not only with geometric configuration but also with fatty acid chain length ...
Ulhaq S S Department of Pharmacy and Pharmacology, University of Bath, Claverton Down, - - 1999
L-Thiocitrulline is a known potent inhibitor of several isoforms of nitric oxide synthase (NOS). To explore the structure-activity relationships (SARs) for this molecule in more depth than has previously been reported, three analogues substituted at the sulphur of the isothioureas have been synthesised. In two of these, the S-substituent was ...
Carballeira N M - - 1999
The delta 5,9 fatty acids (5Z,9Z)-5,9-hexadecadienoic acid, (5Z,9Z)-5,9-nonadecadienoic acid, and (5Z,9Z)-5,9-eicosadienoic acid were synthesized for the first time in four steps (9-12% overall yield) starting from commercially available 2-(2-bromoethyl)-1,3-dioxolane. The synthetic approach provided enough material to corroborate the structure and stereochemistry of (5Z,9Z)-5,9-nonadecadienoic acid which was recently identified in the ...
Martín M - - 1999
Fatty acid omega3 desaturases act on membrane lipids to catalyse the formation of trienoic fatty acids, the most abundant in plant tissues being alpha-linolenic acid. This fatty acid is a precursor of jasmonic acid, a plant growth regulator involved in the control of wound-induced gene activation in plants and in ...
Toledo M S - - 1999
Significant differences exist between mammals and fungi with respect to glycosphingolipid (GSL) structure and biosynthesis. Thus, these compounds, as well as the cellular machinery regulating their expression, have considerable potential as targets for the diagnosis and treatment of fungal diseases. In this study, the major neutral GSL components extracted from ...
Langer S - - 1999
Topical 5-aminolevulinic acid is used for the fluorescence-based diagnosis and photodynamic treatment of superficial precancerous and cancerous lesions of the skin. Thus, we investigated the kinetics of 5-aminolevulinic acid-induced fluorescence and the mechanisms responsible for the selective formation of porphyrins in tumors in vivo. Using amelanotic melanomas (A-Mel-3) grown in ...
Vilas G L - - 1999
The aim of this work is to study the effect of thioctamide--the commercial form of alpha lipoic acid amide--on the porphyrinogenic action of hexachlorobenzene (HCB). For this purpose, porphyria was induced in rats by chronic HCB treatment, with or without simultaneous thioctamide administration. Two different groups of rats were used ...
Nakano N - - 1999
9,12-Hexadecadienoic acid (16:2 n-4), present in small amounts in fish oils as a naturally occurring unique fatty acid, was incorporated into the phospholipids in rat liver BRL-3A cells to a similar extent as linoleic acid (18:2 n-6). 11,14-Octadecadienoic acid (18:2 n-4) and 8,11,14-octadecatrienoic acid (18:3 n-4) were detected in the ...
Suh M C - - 1999
Seeds of coriandrum sativum (coriander) and Thunbergia alata (black-eyed Susan vine) produce unusual monoenoic fatty acids which constitute over 80% of the total fatty acids of the seed oil. The initial step in the formation of these fatty acids is the desaturation of palmitoyl-ACP (acyl carrier protein) at the delta(4) ...
Sakuradani E - - 1999
Based on the sequence information for delta 9-desaturase genes (from rat, mouse and yeast), which are involved in the desaturation of palmitic acid and stearic acid to palmitoleic acid and oleic acid, respectively, the corresponding cDNA and genomic gene were cloned from the fungal strain, Mortierella alpina 1S-4, which industrially ...
Boger D L - - 1999
The examination of a series of trifluoromethyl ketone inhibitors of Fatty Acid Amide Hydrolase (FAAH, oleamide hydrolase, anandamide amidohydrolase) is detailed in efforts that define structural and conformational properties that contribute to enzyme inhibition and substrate binding. The results imply an extended bound conformation, highlight a role for the presence, ...
Matin A - - 1999
The acidophilic bacteria comprise an environmentally important group that includes pathogens. A fundamental requirement for existence in strongly acidic environments is generation of a large pH gradient (delta pH) to maintain the cytoplasmic pH near neutrality and safeguard the acid-labile cell constituents. These organisms require the capacity to extrude H+ ...
Quintela J C - - 1999
Peptidoglycan from Deinococcus radiodurans was analyzed by high-performance liquid chromatography and mass spectrometry. The monomeric subunit was: N-acetylglucosamine-N-acetylmuramic acid-L-Ala-D-Glu-(gamma)-L-Orn-[(delta)Gly-Gly]-D-Ala-D-Ala. Cross-linkage was mediated by (Gly)2 bridges, and glycan strands were terminated in (1-->6)anhydro-muramic acid residues. Structural relations with the phylogenetically close Thermus thermophilus are discussed.
Mino K - - 1999
Incubation of serine acetyltransferase (SAT) from Escherichia coli at 25 degrees C in the absence of protease inhibitors yielded a truncated SAT. The truncated SAT was much less sensitive to feedback inhibition than the wild-type SAT. Analyses of the N- and C-terminal amino acid sequences found that the truncated SAT ...
Brune A - - 1998
Citrate transport into the vacuoles of acid lime juice cells was investigated using isolated tonoplast vesicles. ATP stimulated citrate uptake in the presence or in the absence of a Delta mu H+. Energization of the vesicles only by an artificial K+ gradient (establishing an inside-positive Delta psi) also resulted in ...
Winkler D - - 1998
Analogs of Met-enkephalin and [D-Pen2, D-Pen5]enkephalin (DPDPE) containing the partially fluorinated amino acid 4,4-difluoro-2-aminobutyric acid (DFAB) in the 2- or 3-position of the peptide sequence were synthesized and their opioid activities and receptor selectivities were determined in vitro. The linear fluorinated [D-DFAB2, Met5-NH2]enkephalin showed mu and delta agonist potencies comparable ...
El-Naggar G A - - 1998
The First and second dissociation constants of adipic acid were determined by EMF measurements in water/methanol mixtures with 0, 30, 50 and 70 wt% organic cosolvent. Measurements were made at four different temperatures (ranging from 30 to 60 degrees C) using the cell: glass electrode/HCL (m(1)), H(2)L (m(2)), Na(2)CO(3) (m(3))/AgCl ...
John H - - 1998
It is shown that 12-(S)-hydroxy-(5Z, 8E, 10E)-heptadecatrienoic acid (5-cis-HHT)--a physiological metabolite of arachidonic acid--is acid-catalyzed converted into a less polar substance with its maximum UV-absorption at (1)max=232 nm and a molar absorptivity of about epsilon=26600 +/- 200 M(-1)cm(-1). Using a reversed-phase high-performance liquid chromatographic (HPLC) method this equilibrium reaction (K(c) ...
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