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PubMed2005

A new method for concentration of proteins in the calcareous corpuscles separated from the spargana of Spirometra erinacei.

Calcareous corpuscles are a characteristic structure found in larval and adult stage cestodes. These corpuscles are known to contain several protein components and to possess protein-binding activity. However, the proteins bound to calcareous corpuscles in situ have not been studied. The present study was undertaken to identify the proteins on calcareous corpuscles. Calcareous corpuscles were purified from the plerocercoids (= spargana) of Spirometra erinacei, and serially dissolved using 0.1 M sulfamic acid solution. Collected supernatants were examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and silver staining. The results showed that only the fraction remaining after the 19th dissolved fraction contained proteins. A total of 20 protein molecules were detected in gel, with major bands at 56, 53, 46, 40, 35, 29, 28, 24.5, 21, 19, 16, 13, 10 and 8 kDa. In particular, the proteins corresponding to the 21 and 16 kDa bands were most abundant. Our results demonstrated for the first time the protein contents of the calcareous corpuscles of spargana. Further studies on the functions of these proteins are required.

Animals↗
PubMed1988

N-azamonobactams. 1. The synthesis of some 3-substituted N-azamonobactam derivatives.

Ring closure of the N-(tert-butyloxycarbonyl)-L-serine 2-(diphenylmethylene)hydrazide (10a) and the corresponding L-threonine derivative (10b) gave good yields of the beta-lactams 11a and 11b. Catalytic hydrogenation afforded the corresponding N-amino beta-lactams 12a and 12b. These compounds were then further transformed into 3-(S)-[[(2-amino-4-thiazolyl)-(Z)-(methoxyimino)acetyl]amino-2-oxo-1- azetidinyl]sulfamic acid analogs 18, 23, and 30a and 30b. None of these compounds exhibited any interesting biological activity.

Aztreonam↗
PubMed1991

A phase I clinical and pharmacokinetic trial of hepsulfam.

Hepsulfam (1,7-heptanediol-bis-sulfamate) is one of a series of bis-sulfamate acid esters that was synthesized in an attempt to improve the antitumor efficacy of busulfan. Hepsulfam has shown broad antineoplastic activity in preclinical studies. This Phase I trial evaluated hepsulfam given as a single i.v. dose every 21-35 days. Twenty-nine patients with refractory solid tumors participated in this study. Twenty-six of these patients had had either prior chemotherapy or radiation therapy. Fifty-two courses of treatment were given at doses ranging from 30 to 360 mg/m2/day. The dose limiting toxicity was prolonged thrombocytopenia and granulocytopenia. This toxicity was cumulative with Grade 3 or 4 thrombocytopenia occurring in 3 of 15, 4 of 9, and 2 of 2 patients in the first, second, and third courses of greater than or equal to 210 mg/m2, respectively. This toxicity was noted in patients with less than or equal to 1 prior chemotherapeutic regimen, as well as in patients with greater than 1 prior chemotherapeutic regimens. Nonhematological toxicities included Grade 1 or 2 nausea and vomiting and fatigue. There was no evidence of pulmonary toxicity. Plasma levels of hepsulfam were quantified by gas chromatography in 12 patients. The plasma and blood half-lives were 15.9 +/- 4.6 and 90 +/- 13 h, respectively. No objective tumor responses were seen. We conclude that the maximally tolerated dose when hepsulfam is given as a single dose every 35 days is 210 mg/m2, but that there is significant risk of cumulative hematological toxicity at this level.

Aged↗
PubMed1987

An improved method for analysis of total N-nitroso compounds in gastric juice.

An improved procedure for the analysis of total N-nitroso compounds (NOC) in human gastric juice was developed by modifying previous methods. The gastric juice sample, treated with sulfamic acid to remove nitrite, is injected directly into refluxing ethyl acetate containing either acetic acid for determining thermo/acetic acid-labile-thermal energy analyser (TEA)-responsive compounds (TAC), or into hydrogen bromide for the analysis of TAC and NOC. The nitric oxide (NO) levels released are measured by chemiluminescence by TEA, and the difference between the two determinations represents the concentrations of NOC in gastric juice. This method also allows the determination of nitrite and is not affected by nitrate concentrations up to 1,000 mumol/l. The method was found to be reproducible and sensitive (detection limit, 0.02 mumol NOC/l), requiring only small volumes of gastric juice and no prior extraction. Because the difficulties arising from the 'system response' to the denitrosating agent and variability of NO release by acetic acid from nitrite were eliminated, this improved method can more accurately distinguish NOC from most other TEA-responsive species. Suitable techniques for stabilizing gastric juice samples from duodenal ulcer/atrophic gastritis patients and the influence of the time and storage conditions on NOC concentrations have been studied.

Gastric Juice↗
PubMed1981

Gas-liquid chromatographic-thermal energy analyzer determination of N-nitrosodimethylamine in beer at low parts per billion level.

A gas-liquid chromatographic (GLC) procedure is described for the determination of low ppb levels of N-nitrosodimethylamine (NDMA) in beer. The sample is treated with sulfamic acid under acidic conditions followed by alkalinization with dilute KOH, distillation at atmospheric pressure, extraction of NDMA from alkaline aqueous distillate with dichloromethane, concentration of dichloromethane extract by Kuderna-Danish concentrator, and, finally determination by a GLC-thermal energy analyzer technique with N-nitrosodipropylamine (NDPA) as an internal standard. The method gave results comparable with 2 other well established methods. Recoveries of added NDMA, N-nitrosodiethylamine, and NDPA at levels ranging from 0.08 to 10 ppb were 75-112, 86-115, and 85-109%, respectively. Five replicate analyses of a beer sample gave a mean NDMA concentration (corrected for recovery) of 2.21 +/- 0.08 ppb (+/- SD). Minimum detection limit of the method is about 0.1 ppb.

Beer↗
PubMed1981

Volatile N-nitrosamines in dried foods.

An investigation was carried out to determine the levels of volatile N-nitrosamines in several dried food commodities such as malt, instant skim milk powder, infant formula containing milk powder, instant coffee, soup and soup bases, and baby cereals. The method involves vacuum distillation of the sample from 3N KOH or 1% sulfamic acid, followed by extraction of the aqueous distillate with dichloromethane. The dichloromethane extract is then washed with an acidic buffer (to remove amines), dried over anhydrous sodium sulfate, concentrated in a Kuderna-Danish concentrator, and analyzed by gas-liquid chromatography, using a thermal energy analyzer. Detection limit is 0.1-0.5 ppb. Of the samples analyzed thus far, all malts (22 samples) and instant skim milk powders (11 samples ) were positive for N-nitrosodimethylamine (NDMA); average levels were 7.4 ppb (1.3-67.0 ppb) and 0.4 ppb (0.3-0.7 ppb), respectively. Traces of NDMA and/or N-nitrosopyrrolidine were also detected in 3 of 20 dried soups and 5 of 10 instant coffees analyzed. Traces of NDMA and/or N-nitrosopiperidine (NPIP) were detected in 3 of 8 powdered instant formulas. All for baby cereal samples were negative. The identity of NDMA in 14 samples of malt and that of NDMA and NPIP in a infant formula was confirmed by gas liquid chromatography-mass spectrometry; identity of N-nitrosamines in 3 instant coffees and 1 infant formula was independently verified by high pressure liquid chromatographic analysis.

Chromatography, High Pressure Liquid↗
PubMed1999

Biological monitoring of workers exposed to 4,4'-methylene-bis-(2-orthochloroaniline) (MOCA). II. Comparative interest of "free" and "total" MOCA in the urine of exposed workers.

OBJECTIVES: The objectives of the study were to investigate the best urinary marker of exposure to MOCA in urine samples of exposed workers and to study its applicability in exposure evaluation in polyurethane resin production plants. In addition, our intention was to contribute to the question of biological target value in order to reduce exposure levels. METHODS: Urinary MOCA markers were measured in urine samples collected at the end of the workshifts. 40 workers from four factories were observed for three consecutive days in the same week. "Free" MOCA in non-acid-stabilized urines, "total" MOCA in urines after alkaline hydrolysis, "acid-labile" MOCA in sulfamic or citric acid-protected urines were measured in all urine samples. MOCA liberated by heating the non-acid-stabilized urines ("heat-labile" MOCA) was also measured in 17 urine samples of exposed workers. RESULTS: The median value of "free" MOCA was lower than that of "sulfamic acid-labile" MOCA: 6.0 and 12.5 micrograms/l respectively. The difference between "free" and "total" MOCA was statistically significant (Mann-Whitney test, P = 0.023) for the urine samples collected without acid. Correlations between urinary MOCA concentrations in hydrolysed and non-hydrolysed urine samples were high (r = 0.984, 0.966 and 0.950; P < 0.001) for urine samples with sulfamic acid, with citric acid and without acid respectively. For all the factories, the postshift urinary MOCA concentrations ranged between 1 microgram/l (detection limit) and 570 micrograms/l; 25% of "sulfamic acid-labile" MOCA concentrations exceeded 50 micrograms/l. Workers handling crystallized MOCA excreted the highest amounts of MOCA in urine. The urinary MOCA concentrations (median) were: 84.0 micrograms/l (mixer), 15.5 micrograms/l (moulder). 59.0 micrograms/l (maintenance) and 3.0 micrograms/l (others). CONCLUSIONS: MOCA measured in sulfamic acid-protected urine samples without hydrolysis provides a more practical and reliable biomarker than "total" MOCA (after hydrolysis) or "free" MOCA. A biological guiding value of 20 micrograms/l expressed as "sulfamic acid-labile" MOCA is proposed.

Chemical Industry↗
PubMed2000

The sulfamate functional group as a new anchor for solid-phase organic synthesis

[reaction: see text] Sulfamate derivatives were loaded on trityl chloride resin, and two variants of cleavage were developed for this sulfamate anchor: an acid treatment to easily restore the free sulfamate and a nucleophilic treatment to generate the corresponding phenol. In addition to loading/cleavage assays and stability experiments, a model sequence of reactions was performed with the new sulfamate anchor to show its applicability in further combinatorial solid-phase synthesis of libraries of biologically relevant sulfamate derivatives.

Journal Article↗
PubMedDate not supplied

Metabolism of the food mutagen 2-amino-3-methylimidazo[4,5-f]quinoline in nonhuman primates undergoing carcinogen bioassay.

2-Amino-3-methylimidazo[4.5-f]quinoline (IQ) is a potent bacterial mutagen and rodent carcinogen which also produces hepatocellular carcinoma in monkeys. The metabolism and disposition of this procarcinogen were investigated in monkeys undergoing carcinogen bioassay and in monkeys given an acute dose of IQ. Analysis of urine, feces, and bile revealed that IQ was extensively metabolized. A number of metabolites in urine were purified by high-performance liquid chromatography and characterized by 1H NMR and mass spectroscopy. Metabolites resulted from cytochrome P450-mediated ring oxidation at the C-5 position or N-demethylation. These metabolites could be further transformed by conjugation to sulfate or beta-glucuronic acid. Glucuronidation and sulfamate formation at the exocyclic amine group were other major routes of metabolism. Enteric bacteria also contributed to IQ biotransformation by forming the 7-oxo derivatives of IQ and N-demethyl-IQ. The metastable N2-glucuronide conjugate of the carcinogenic metabolite, 2-(hydroxyamino)-3-methylimidazo[4,5-f]quinoline, was found in urine. This indicates that metabolic activation through cytochrome P450-mediated N-oxidation occurs in vivo and that glucuronidation is a means of transport of the carcinogenic metabolite to extrahepatic tissues.

Animals↗
PubMed1993

Carbonic anhydrase inhibitory activity and ocular pharmacology of organic sulfamates.

Organic sulfamates are a new variation to the carbonic anhydrase (CA) inhibitor structure-action relationship. Inhibitory activity is conferred by the classic sulfonamide group, but through linkage to the benzene ring by an oxygen. AHR-16329, a representative sulfamate, has an acidic (sulfonamide, pKa 8.9) and basic (imidazole, pKa 6.0) group and has desirable physicochemical properties for topical intraocular pressure lowering: good water solubility below pH 6.0, a CHCl3/buffer ratio of 0.5 at pH 7.0 and a Kl against CA-II of 7 nM. Inhibition of CO2 hydration is noncompetitive. When applied locally to the eye, AHR-16329 reaches significant levels in ocular tissues and fluids and reduces significantly intraocular pressure. Five percent concentration gives the greatest reduction, equivalent to systemic inhibitors; 2 and 5% have similar pressure x time duration. These studies expand structure-action relations in the field of CA inhibitors and the validity of developing topical CA inhibitors for treatment of glaucoma.

Animals↗
PubMed2003

Effect of estradiol sulfamate (ES-J995) on affinity of hemoglobin for oxygen, cardiovascular function and acid-base balance in ovariectomized rats.

Oral administration of estradiol sulfamate (ES, prodrug of estradiol) leads to increased systemic and reduced hepatic effects than estradiol because ES is accumulated in erythrocytes. However, possible alterations of erythrocytic oxygen transport by intraerythrocytic ES accumulation has not been studied. Therefore, ovariectomized adult female rats (n = 58; body wt.) were randomly treated orally either with single doses (day 1) or multiple dose (days 1-4) with vehicle, with estradiol sulfamate (ES-J995, 1 mg x kg(-1) b.w.) or with estradiol (30 mg x kg(-1) b.w.). Under general anesthesia arterial blood pressure, heart rate, blood gases, and acid-base balance were measured. Hypoxia was performed by lowering the inspired fraction of oxygen from 0.35 to 0.12. In addition, individual oxygen dissociation curves and ES-J995 distribution in blood and plasma were estimated. ES-J995 was accumulated in erythrocytes by approximately 98% (P < 0.01), but oxygen transport capacity was not altered (P50: 35.6 +/- 1.0 mm Hg to 37.1 +/- 1.1 mm Hg). Blood gases and acid-base balance parameters were not altered after ES-J995 treatment under normoxic and hypoxic conditions. In conclusion, ES-J995 accumulation in erythrocytes does not alter the affinity of hemoglobin for oxygen nor any function which would indicate an impaired oxygen delivery to the body.

Acid-Base Imbalance↗
PubMed2004

Carbonic anhydrase inhibitors. Inhibition of the beta-class enzyme from the methanoarchaeon Methanobacterium thermoautotrophicum (Cab) with anions.

The first inhibition study of the beta-class carbonic anhydrase (CA, EC 4.2.1.1) from the methanoarchaeon Methanobacterium thermoautotrophicum (Cab) with anions is reported here. Inhibition data of the alpha-class human isozymes hCA I and hCA II (cytosolic) as well as the membrane-bound isozyme hCA IV and the gamma-class enzyme from another archaeon, Methanosarcina thermophila (Cam) with a large number of anionic species such as halides, pseudohalides, bicarbonate, carbonate, nitrate, nitrite, hydrosulfide, bisulfite, sulfate, etc., are also provided for comparison. The best Cab anion inhibitors were thiocyanate and hydrogen sulfide, with inhibition constants in the range of 0.52-0.70 mM, whereas cyanate, iodide, carbonate, and nitrate were weaker inhibitors (Ki's in the range of 7.8-13.2 mM). Fluoride, chloride, and sulfate do not inhibit this enzyme appreciably, whereas the CA substrate bicarbonate, or other anions, such as bromide, nitrite, bisulfite, or sulfamate behave as weak inhibitors (Ki in the range of 40-45 mM). It is interesting to note that the metal poison, coordinating anions cyanide and azide are also rather weak Cab inhibitors (Ki in the range of 27-55 mM), whereas sulfamide is a very weak Cab inhibitor (Ki of 103 mM), although it strongly inhibits Cam (Ki of 70 microM). Surprisingly, phenylboronic and phenylarsonic acids, which have been investigated for the inhibition of all these CAs for the first time, showed very weak activity against the alpha-CA isozymes, but were effective Cab and Cam inhibitors. The best Cab inhibitors were just these two compounds (Ki's of 0.20-0.33 mM), whereas the best Cam inhibitor was sulfamic acid (Ki of 96 nM). These major differences of behavior between the diverse CAs investigated here toward anion inhibitors can be difficultly explained considering the convergent evolution of so diverse enzymes for the binding and turnover of small molecules such as carbon dioxide and anions.

Anions↗
PubMed1998

Taste preference in nonhuman primates to compounds sweet in man.

Primates have stimulated more interest than any other group as humans are ranked in this same mammalian order. Gustatory responses of human and nonhuman primates have already been compared for compounds such as monosaccharides, oligosaccharides, polyols, amino acids, dipeptides, proteins, dihydrochalcones, sulfamates, saccharin, acesulfame, diterpenes or urea derivatives, all known to be sweet in man. But no rational comparison in primates has been attempted. Using a structure-activity relationship study in primates, it is now possible to classify the primate sweetness receptors into four types according to the behavioral responses observed from various selected compounds sweet in humans. The four types are represented by (1) the Callitrichidae and (2) the Cebidae, both from the infraorder Platyrrhini (New World monkeys), (3) the Lemuridae and Lorisidae, from the suborder Prosimii (prosimians), and (4) the Cercopithecidae (Old World monkeys), Hylobatidae (lesser apes), Pongidae (great apes), and Hominidae (humans) from the infraorder Catarrhini (Old World simians). By a comparative study of the putative receptor recognition sites postulated for each type of receptor, it is inferred that the Callitrichidae (marmosets and tamarins) have retained the most primitive sweetness receptor among primates. As we believe that the evolution of the sweetness receptor is a key factor involved in the raising of nonhuman primates from a 'primitive grade' towards a more 'advanced' or 'simian grade,' the possible phylogenetic implications of these findings will be discussed.

Animals↗
PubMed2006

Carbonic anhydrase inhibitors: inhibition of the cytosolic human isozyme VII with anions.

An inhibition study of the cytosolic carbonic anhydrase (CA, EC 4.2.1.1) isozyme VII (hCA VII) with anions has been conducted. Cyanate, cyanide, and hydrogensulfite were weak hCA VII inhibitors (K(I)s in the range of 7.3-15.2 mM). Cl- and HCO3- showed good inhibitory activity against hCA VII (K(I)s of 0.16-1.84 mM), suggesting that this enzyme is not involved in metabolons with anion exchangers or sodium bicarbonate cotransporters. The best inhibitors were sulfamate, sulfamide, phenylboronic, and phenylarsonic acid (K(I)s of 6.8-12.5 microM).

Animals↗
PubMed1995

Sulfhydryl oxidation and activation of red cell K(+)-Cl- cotransport in the transgenic SAD mouse.

The SAD mouse is characterized by the expression of human SAD hemoglobin (Hb), a super S Hb with a higher tendency to polymerize than HbS due to the presence of two additional mutations, Antilles beta 23Ile and D Punjab beta 121Glu. Monovalent cation transport was studied in erythrocytes from SAD-1 (Hb SAD = 19%) and beta-thal/SAD-1 (Hb SAD = 26%) mice. Erythrocytes containing Hb SAD exhibited dehydration, increased maximal rate of Na(+)-K+ pump, unchanged Rb+ flux via the Gardos channel, and increased K(+)-Cl- cotransport. K(+)-Cl- cotransport was defined as Cl(-)-dependent (substitution with sulfamate or methanesulfonate) okadaic acid-sensitive K+ efflux. Volume regulatory decrease via K(+)-Cl- cotransport was also increased in swollen SAD erythrocytes compared with controls. K(+)-Cl- cotransport was stimulated by staurosporine in all mouse strains, but the extent of stimulation was reduced in beta-thal/SAD-1 mice. Treatment with dithiothreitol reduced K(+)-Cl- cotransport activity in SAD-1 and beta-thal/SAD-1 mice to levels similar to that of control strains, indicating that reversible sulfhydryl oxidation contributes to the activated state of K(+)-Cl- cotransport in mouse erythrocytes that express transgenic human Hb SAD.

Animals↗
PubMed1980

Kinetics of nitrosamine formation in mice following oral administration of trace-level precursors.

Groups of 3-5 Swiss CD1 mice were gavaged with aqueous solutions of sodium nitrite (250 micrograms), followed immediately by morpholine (5 micrograms) or dimethylamine (250 micrograms). At subsequent intervals, up to 30-60 min, mice were frozen, pulverized in liquid nitrogen and extracted with methylene chloride. Volatile nitrosamines were then quantitatively determined using a Thermal Energy Analyzer, interfaced to GC or HPLC. Biosynthesis of both N-nitrosodimethylamine (NDMA) and N-nitrosomorpholine (NMOR) showed a time-dependent increase for 3 and 9 min, respectively, followed by a steady decline. Levels of NDMA and NMOR were generally less than 0.1 ng/g in control mice gavaged with amine or nitrite alone. Zero-time recovery of NDMA and NMOR ranged from 50-70% and 70-90%, respectively. Biosynthesis of NDMA and NMOR was inhibited by prior administration of ascorbic acid, sodium ascorbate or ammonium sulfamate.

Administration, Oral↗
PubMed2004

Carbonic anhydrase inhibitors: aliphatic N-phosphorylated sulfamates--a novel zinc-anchoring group leading to nanomolar inhibitors.

A small library of phosphorylated sulfamates (N-(O-alkylsulfamoyl)-phosphoramidic acids) incorporating long aliphatic chains (C8-C16) has been synthesized and investigated for their interaction with two physiologically relevant carbonic anhydrase (CA) isozymes. These compounds behaved as very potent inhibitors of both isozymes, with inhibition constants in the range of 8.2-16.1nM against isozyme hCA I, and 5.3-11.9nM against isozyme hCA II. Activity was optimal for the n-octyl derivative (similarly with that of the corresponding unsubstituted sulfamates) and gradually decreased for the longer chain derivatives. Some of these compounds are much more effective CA inhibitors as compared to the clinically used derivatives acetazolamide, sulfanilamide or topiramate, which are used as standards for the enzymatic determinations. The phosphorylated sulfamate moiety represents a novel zinc-binding group for the design of effective CA inhibitors.

Binding Sites↗