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PubMedDate not supplied

Determination of sulfonamides in edible salmon tissue by liquid chromatography with postcolumn derivatization and fluorescence detection.

Fourteen sulfonamides-sulfanilamide, sulfadiazine, sulfathiazole, sulfapyridine, sulfamerazine, sulfamethazine, sulfamethizole, sulfamethoxypyridazine, sulfachloropyridazine, sulfamonomethoxine, sulfadoxine, sulfamethoxazole, sulfadimethoxine, and sulfaquinoxoline-residues of which could be found in aquacultured species, were separated in < 25 min by reversed-phase (C18) liquid chromatography (LC) with gradient elution. Analytes were extracted from edible salmon tissue (muscle and adhering skin) with acetonitrile-2% aqueous acetic acid, isolated with 2 liquid-liquid partitionings, and derivatized with fluorescamine after eluting from the column. The derivatives were detected by fluorescence. Recoveries (n = 4) from coho salmon fortified with sulfonamides at 5, 10, and 20 ng/g tissue averaged 79.7 +/- 7.3, 84.6 +/- 7.7, and 88.2 +/- 7.1%, respectively. Limits of quantitation were 5 ng/g tissue, for sulfanilamide, sulfamethoxypyridazine, and sulfaquinoxoline and 1 ng/g tissue for the remaining sulfonamides.

Acetic Acid↗

PubMed1996

Bicarbonate absorption in eel intestine: evidence for the presence of membrane-bound carbonic anhydrase on the brush border membranes of the enterocyte.

Bicarbonate absorptive fluxes through the isolated intestine of the European eel (Anguilla anguilla) were evaluated by the pH-stat method under short-circuited conditions. It was found that bicarbonate absorptive flux was dependent on the luminal Na+ and was inhibited by luminal 4-acetamido-4' stilbene-2-2' disulfonic acid (SITS; 2.5 x 10(-4) M) and luminal acetazolamide (10(-4) M), while luminal amiloride (1 mM) was without effect. Furthermore, by using brush border membrane vesicles (BBMV) isolated from eel intestine, the existence of two carbonic anhydrase (CA) isoforms, one tightly associated to the brush border membrane (BBM) and the other soluble in the cytosol, was demonstrated. The membrane-bound CA differs from the cytoplasmic isoform in that 1) it is relatively resistant to treatment with 0.045% lauryl sulfate sodium salt (SDS); 2) it is less inhibitable by ethoxzolamide and sulfanilamide; and 3) its Kmapp is significantly lower than that of the cytoplasmic isoform. These results suggest that a BBM-bound CA isozyme would play an important role in bicarbonate absorption from the lumen, facilitating the HCO3- transfer through the luminal membrane of the eel enterocyte most likely via a Na+ (HCO3-) or (OH-) cotransport system.

Anguilla↗

PubMed1991

Use of differential scanning potentiometry in pharmaceutical analysis.

The use of differential scanning potentiometry (DSP) to assay pure drugs and mixtures is illustrated through a set of model cases. The profiles obtained by scanning glycine (0.3 mmol), sulfanilamide (0.3 mmol), epinephrine (0.06 mmol), and norfloxacin (0.05 mmol) are reported, as well as the areas (A+, A-, and At) obtained in each scan. Such information is useful to assess identity and/or chemical purity and to get the pKa of the ionizing groups of the drugs. The degree of hydrolysis of a parenteral solution of procaine hydrochloride is also determined through DSP as an example of mixture assay. Comparison with conventional aqueous acid-based potentiometry shows that the new technique exhibits much better performance to assay small samples or samples carrying weak acidic and/or basic groups.

Chemistry, Pharmaceutical↗

PubMed1992

Enhancement of percutaneous absorption by laurocapram.

The in vitro treatment of shed snake skin and hairless rat skin with laurocapram resulted in dramatic decreases in the amounts of cholesterol, phospholipids, and ceramides but not triglycerides in the skins. Scanning electron microscopic observations of hairless rat skin treated with laurocapram indicated looseness and cell separation of the stratum corneum probably caused by the extensive extraction of the intercellular lipids. An ESR study demonstrated the increased fluidity of the corneum lipids after laurocapram treatment. The apparent rotational correlation time of 16-doxyl-stearic acid was decreased by 1.6-2 times after treatment with laurocapram. No penetration of laurocapram itself through shed snake skin and hairless rat skin was detected in vitro, except when the reservoir solvent was 60% ethanol or propylene glycol. The enhancer was hardly metabolized during a 48-h incubation with skin homogenate. Pretreatment of shed snake skin with laurocapram increased significantly the penetration of sulfanilamide and indomethacin through the skin. These results indicate that laurocapram penetrating into the stratum corneum interacts with structured lipids in the intercellular channels and releases them, thereby enhancing the penetration of hydrophilic drugs through the channels. Additionally, laurocapram penetrating into the intracellular matrix of the corneum fluidizes the intracellular lipids and causes the reduction of diffusional resistance.

Administration, Cutaneous↗

PubMed2000

Disruption of cytoplasmic and mitochondrial folylpolyglutamate synthetase activity in Saccharomyces cerevisiae.

Similar to other eukaryotes, yeasts have parallel pathways of one-carbon metabolism in the cytoplasm and mitochondria and have folylpolyglutamate synthetase activity in both compartments. The gene encoding folylpolyglutamate synthetase is MET7 (also referred to as MET23) on chromosome XV and appears to encode both the cytoplasmic and mitochondrial forms of the enzyme. In order to determine the metabolic roles of both forms of folylpolyglutamate synthetase, we disrupted the met7 gene and determined that the strain is a methionine auxotroph and an adenine and thymidine auxotroph when grown in the presence of sulfanilamide. The met7 mutant becomes petite under normal growth conditions but can be maintained with a grande phenotype if the strain is tup and all media are supplemented with dTMP. A met7 gly1 strain is auxotrophic for glycine when grown on glucose but prototrophic when grown on glycerol. A met7 ser1 strain cannot use glycine to suppress the serine auxotrophy of the ser1 phenotype. A met7 shm2 strain is nonviable. In order to disrupt just the mitochondrial folylpolyglutamate synthetase activity, we constructed mutants with an inactivated chromosomal MET7 gene complemented by genes that express only cytoplasmic folylpolyglutamate synthetase, including the Lactobacillus casei folC gene and the yeast MET7 gene with its mitochondrial leader sequence deleted (MET7Deltam). All the genes providing cytoplasmic folylpolyglutamate synthetase complemented the methionine auxotrophy as well as the synthetic lethality of the shm2 strain and the synthetic glycine auxotrophy of the gly1 strain. The strains lacking the mitochondrial folylpolyglutamate synthetase had longer doubling times than the isogenic wild-type strains but retained the function of the mitochondrial folate-dependent enzymes to produce formate, serine, and glycine. Mutants complemented by the bacterial folC gene or by the MET7Deltam gene on a 2mu plasmid remained grande without the tup mutation and supplementation and dTMP. Mutants complemented by the MET7Deltam gene integrated in single copy became petites under those conditions, indicating a deficiency in dTMP production but this is likely due to lower expression of cytoplasmic folylpolyglutamate synthetase by the MET7Deltam gene.

Amino Acids↗

PubMed1998

Nitrosothiol quantification in human plasma.

A high-pressure liquid chromatography (HPLC) assay for measuring picomole quantities of nitrosothiol in biological samples was developed. The assay utilizes the catalytic reduction of nitrosothiol by mercuric cation (Hg2+). Released nitrogen oxide reacts with sulfanilamide (SA) and N-(1-napthyl)ethylenediamine (NNED) to form a stable azo dye. The azo dye is then separated from N-(1-napthyl)ethylenediamine and quantified by reversed-phase HPLC. In addition to nitrosothiol, nitrite and atmospheric nitrogen oxides are sources of nitrogen oxide that react with the reagents, SA and NNED, to form the azo dye. Therefore, a reference sample, which includes the nitrosothiol sample and all reagents except Hg2+, is utilized for the subtraction of nitrite and atmospheric nitrogen oxides which "contaminate" the nitrosothiol sample and reagents. This method is a sensitive (approximately 3 pmol; approximately 10(-1) microM) and accurate means to measure nitrosothiol concentration in biologic samples.

Azo Compounds↗

PubMed1994

DNA sequence of direct repeats of the sulI gene of plasmid pSa.

The restriction enzyme and genetic map of the antibiotic-resistance region of plasmid pSa is related to Tn21 integrons by the insertion of 5.4 kb containing a chloramphenicol resistance gene (catII) and a 1.1-kb direct repeat. We report here the nucleotide sequences of both copies of the repeat with adjoining sequences. They were identical for 1065 bp and contained the entire coding sequence of the sulfanilamide resistance gene, sulI. Since only the first copy of the repeat confers sulfonamide resistance, this leads to the conclusion that no promoter was available for the second copy. The sequence of the pSa sulI gene was identical to several published sulI sequences from other plasmids. The first junction point of the catII-containing insert was identical to the sequence for pDG0100; the second junction occurred farther into the 3'-conserved segment of integrons than does that of pDG0100. A recent report of these junction sequences for pSa and pDG0100 differs from our sequences by one nucleotide. Two additional differences were an insert of 41 bases and a single base insertion between sulI and ORF341 in our sequence. Our sequenced regions have been assigned GenBank Accession Nos. UO4277 and UO4278 for the first and second sulI genes of pSa, respectively.

Amino Acid Sequence↗

PubMed2002

Test strip for determination of nitrite in water.

A disposable test strip is proposed for the determination of nitrite in waters. The strip is an inert rectangular strip of polyester with a 6 mm o.d. circular, transparent and colorless film attached to its surface. This film contains the chemicals required for reaction and fixation of the dye formed, sulfanilamide, N-(1-naphthyl)ethylenediamine on Nafion. When the test strip is placed in an acidified (pH 2.0) sample solution containing nitrite a red-violet color develops; the absorbance of this is measured at 536 nm. The linear range of the method depends on the time of equilibration of the test strip with the sample solution. When the equilibration time was 45 min, the linear range was 8.9-500 microg L(-1) whereas for an equilibration time of 60 min it was 4.7-200 microg L(-1). The detection limit was 1.4 microg L(-1) for an equilibration time of 60 min. The precision of the method, expressed as RSD, was 8.8 % at 100.0 microg L(-1). The method was applied, and validated chemometrically, for the determination of nitrite in different types of water (spring, mineral, tap, well, and sea).

Color↗

PubMed1984

A dynamic dialysis method for studying protein-ligand binding using chromatographic theory.

A new dynamic dialysis method has been developed for studying protein-ligand binding phenomena. The method depends on analysis of the elution pattern of ligand in a single dialyzing process where the ligand concentration in the sample compartment changes greatly with time. The dialyzer is composed of a long, narrow chamber (the sample compartment) between two sheets of semipermeable membrane and two outside chambers (the sink compartment) connected as a single path. Eluting buffer flows in the sink compartment to exchange the ligand with the solution in the sample compartment. Therefore, the ligand concentration gradient in the sink compartment is in the longitudinal direction. The mathematical expressions to analyze the experimental data were derived from a modified theory of chromatography. Examination of the binding of sulfanilamide to bovine serum albumin using this method shows that these equations are valid for use in studying protein-ligand binding.

Animals↗

PubMed1990

Metabolism of dicarboxylic acids in rat hepatocytes.

[carboxyl-14C]Dodecanedioic acid (DC12) is metabolized in hepatocytes at a rate about two thirds that of [1-14C]palmitate. Shorter dicarboxylates (sebacic (DC10), suberic (DC8), and adipic (DC6) acid) are formed, mainly DC6, less DC8 and only a little DC10. In hepatocytes from clofibrate-treated rats, more polar products account for most of the breakdown products, presumably because the beta-oxidation proceeds all the way to succinate and acetyl-CoA. [carboxyl-14C]Suberic acid (DC8) is oxidized at a rate only one fifth that of dodecanedioic acid. (+)-Decanoylcarnitine inhibits palmitate oxidation but not the oxidation of dodecanedioic acid. At low concentrations of [carboxyl-14C]dodecanedioic acid or of [1-14C]palmitate, acetylsulfanilamide is more efficiently labeled by the former. High concentrations of dodecanedioic acid inhibit palmitate oxidation and the acetylation of sulfanilamide, presumably because their CoA-esters accumulate in the cytosol. These results indicate that medium-chain dicarboxylic acids are beta-oxidized mainly in the peroxisomes.

Acetylation↗

PubMed1991

Inhibition of vitamin B12-dependent microbial growth by nitrous oxide.

In methionine-free media, nitrous oxide inhibits the growth of an auxotrophic strain of Escherichia coli lacking a cobalamin-independent pathway for the de novo synthesis of methionine. Prototrophic E. coli is similarly inhibited by nitrous oxide if the cobalamin-independent pathway is selectively depressed by sulfanilamide. Nitrous oxide thus effectively inactivates cobalamin-dependent 5-methyltetrahydrofolate--homocysteine methyltransferase (methionine synthase, EC 2.1.1.13) in intact bacteria.

Escherichia coli↗

PubMed1991

A three-year photopatch study in Thailand.

Photopatch testing was performed on 274 patients who had history of photosensitivity at the Institute of Dermatology Thailand from 1987 through 1989. A total of 92 positive photocontact reactions and 71 positive contact reactions were seen. The most frequent positive photopatch test reactions were to sulfanilamide (18.2%) followed by Jadit (4.4%) chlorpromazine (3.6%) promethazine (3.6%) and fenticlor (3.2%). The most common photodermatoses was polymorphous light eruption (60.9%). Photocontact dermatitis was established in 28 patients (10.2%) while other skin diseases aggravated by sunlight were seen in 47 patients (17.2%).

4-Aminobenzoic Acid↗

PubMed2005

Carbonic anhydrase inhibitors. Novel sulfanilamide/acetazolamide derivatives obtained by the tail approach and their interaction with the cytosolic isozymes I and II, and the tumor-associated isozyme IX.

A series of sulfonamides has been obtained by reacting sulfanilamide or 5-amino-1,3,4-thiadiazole-2-sulfonamide with omega-chloroalkanoyl chlorides, followed by replacement of the omega-chlorine atom with secondary amines. Tails incorporating heterocyclic amines belonging to the morpholine, piperidine and piperazine ring systems have been attached to these sulfonamides, by means of an alkanoyl-carboxamido linker containing from two to five carbon atoms. The new derivatives prepared in this way were tested as inhibitors of three carbonic anhydrase (CA, EC 4.2.1.1) isozymes, the cytosolic isozymes CA I and II, and the catalytic domain of the transmembrane, tumor-associated isozyme CA IX. Several low nanomolar CA I and CA II inhibitors were detected both in the aromatic and heterocyclic sulfonamide series, whereas the best hCA IX inhibitors (inhibition constants in the range of 22-35 nM) all belonged to the acetazolamide-like derivatives.

Acetazolamide↗

PubMed2006

Base excision repair of both uracil and oxidatively damaged bases contribute to thymidine deprivation-induced radiosensitization.

PURPOSE: Increased cellular sensitivity to ionizing radiation due to thymidine depletion is the basis of radiosensitization with fluoropyrimidine and methotrexate. The mechanism responsible for cytotoxicity has not been fully elucidated but appears to involve both the introduction of uracil into, and its removal from, DNA. The role of base excision repair of uracil and oxidatively damaged bases in creating the increased radiosensitization during thymidine depletion is examined. METHODS AND MATERIALS: Isogenic strains of S. cerevisiae differing only at loci involved in DNA repair functions were exposed to aminopterin and sulfanilamide to induce thymidine deprivation. Cultures were irradiated and survival determined by clonogenic survival assay. RESULTS: Strains lacking uracil base excision repair (BER) activities demonstrated less radiosensitization than the parental strain. Mutant strains continued to show partial radiosensitization with aminopterin treatment. Mutants deficient in BER of both uracil and oxidatively damaged bases did not demonstrate radiosensitization. A recombination deficient rad52 mutant strain was markedly sensitive to radiation; addition of aminopterin increased radiosensitivity only slightly. Radiosensitization observed in rad52 mutants was also abolished by deletion of the APN1, NTG1, and NTG2 genes. CONCLUSION: These data suggest radiosensitization during thymidine depletion is the result of BER activities directed at both uracil and oxidatively damaged bases.

Aminopterin↗

PubMedDate not supplied

Pharmacokinetics of organic anions in rats with arterial calcinosis.

1. Ageing induces calcium accumulation in the vascular system. The simplest experimental way of producing high degrees of arterial calcium overload is by administration of an overdose of vitamin D(3) to rats. The aim of the present study was to evaluate the pharmacokinetics of organic anions in rats with arterial calcinosis induced by an overdose of vitamin D(3). 2. We used bromosulfophthalein (BSP) and sulfanilamide (SA) as models of organic anions with preferential biliary and renal excretion, respectively. 3. Increases in the clearance and elimination rate constant of BSP were observed in treated rats. The clearance and the elimination rate constant for SA were also increased in rats with arterial calcinosis. 4. Variations in arterial hepatic blood flow, aspartate aminotransferase activity and liver calcium accumulation were not observed in treated rats. In contrast, treated rats had a lower renal blood flow and increased renal calcium levels. 5. In summary, rats with arterial calcinosis showed an increase in total body clearance of both BSP and SA, probably associated with modifications in their metabolism and/or in organ extraction. Alterations to hepatic and renal blood flow do not account for these phenomena.

Animals↗

PubMed1953

The permeability of human sweat glands to a series of sulfonamide compounds.

A series of sulfonamide compounds, para-aminohippurate, and inulin were used to study the permeability of the epithelium of human sweat glands. Inulin was not excreted in the sweat. The ratios of the concentrations in sweat to the concentrations in plasma, S/P, of sulfanilamide, sulfapyridine, sulfathiazole, sulfadiazine, and para-aminohippurate were found to be 0.69, 0.58, 0.13, 0.11, and 0.02 respectively, independent of the plasma concentrations and the sweating rates. The fact that the S/P ratios are thus unaffected by the absolute number of molecules transported suggests that these compounds enter into the sweat by simple diffusion and not via a specific secretory mechanism which could become saturated by increasing load. If this is so, the difference in the S/P ratios must be explained by an unequal permeability of the epithelium of the sweat gland to the various compounds and some explanation for these differences in the rate of excretion must exist in terms of physicochemical properties of the compounds. A comparison between the S/P ratios and the pK values of the various sulfonamides indicates that the differences in their rates of excretion in the sweat depend upon the degree of ionization of the various compounds at the physiological pH. Compounds which are mainly non-ionized are excreted with high S/P ratios, whereas ionized compounds appear with low ratios. A quantitative relationship was shown to exist between the S/P ratio for each compound and the percentage of the compound which is non-ionized at pH 7.4.

Humans↗

PubMed1996

13C nuclear magnetic resonance detection of interactions of serine hydroxymethyltransferase with C1-tetrahydrofolate synthase and glycine decarboxylase complex activities in Arabidopsis.

In C3 plants, serine synthesis is associated with photorespiratory glycine metabolism involving the tetrahydrofolate (THF)-dependent activities of the glycine decarboxylase complex (GDC) and serine hydroxymethyl transferase (SHMT). Alternatively, THF-dependent serine synthesis can occur via the C1-THF synthase/SHMT pathway. We used 13C nuclear magnetic resonance to examine serine biosynthesis by these two pathways in Arabidopsis thaliana (L.) Heynh. Columbia wild type. We confirmed the tight coupling of the GDC/ SHMT system and observed directly in a higher plant the flux of formate through the C1-THF synthase/SHMT system. The accumulation of 13C-enriched serine over 24 h from the GDC/SHMT activities was 4-fold greater than that from C1-THF synthase/SHMT activities. Our experiments strongly suggest that the two pathways operate independently in Arabidopsis. Plants exposed to methotrexate and sulfanilamide, powerful inhibitors of THF biosynthesis, reduced serine synthesis by both pathways. The results suggest that continuous supply of THF is essential to maintain high rates of serine metabolism. Nuclear magnetic resonance is a powerful tool for the examination of THF-mediated metabolism in its natural cellular environment.

Amino Acid Oxidoreductases↗

PubMed1984

Expression of plasmid R388-encoded type II dihydrofolate reductase as a dominant selective marker in Saccharomyces cerevisiae.

The R388 plasmid-encoded drug-resistant type II dihydrofolate reductase gene (R . dhfr) was expressed in Saccharomyces cerevisiae by fusing the R . dhfr coding sequence to the yeast TRP5 promoter. Yeast cells harboring these recombinant plasmids grew in media with 10 micrograms of methotrexate per ml and 5 mg of sulfanilamide per ml, a condition which inhibits the growth of wild-type cells. Addition of a 390-base-pair fragment from the 3'-noncoding region of TRP5 downstream from R . dhfr increased expression. Presumably, the added segment promoted termination or polyadenylation or both of the R . dhfr transcript. The activity of the plasmid-encoded dihydrofolate reductase and the copy number of the R . dhfr plasmid in cells grown in drug-selective media were higher by one order of magnitude than those grown in nutrition-selective media. Plasmid copy number, as well as the plasmid-encoded enzyme level, decreased when cells were selected for prototrophy. In drug-selective media, the plasmid-encoded enzyme level and the content of R . dhfr transcripts were nearly constant in cells harboring R . dhfr plasmids containing different yeast promoters. In contrast, the plasmid copy number and beta-lactamase activity encoded in cis by plasmids were much higher when R . dhfr was associated with the weak TRP5 promoter than when it was fused to the strong ADC1 promoter. These results indicate that plasmid copy number, i.e., gene dosage of R . dhfr, correlates inversely with the strength of the promoter associated with R . dhfr, and cells with a higher plasmid copy number were enriched in drug-selective media. The transformation efficiency of R . dhfr fused to the ADC1 promoter was almost the same on drug-selective plates as on nutrition-selective plates, indicating that R . dhfr is suitable as a dominant selective transformation marker in S. cerevisiae.

DNA Restriction Enzymes↗