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At least 703 records · Page 39Linked to original sources
PubMed2001

pH changes in dental plaque after using sugar-free pediatric medicine.

The aim of this study was to compare the pH changes in the dental plaque after rinsing with sugared- (sucrose) or sugar-free (saccharine, cyclamate and sorbitol) versions of the same pediatric acetaminophen solution (ekosetol) up to one hour. Twenty-nine undergraduate dental students (17 girls and 12 boys) collected plaque for 48 hours by abstaining from oral hygiene, during which period they maintained normal dietary habits. Plaque sampling was done in two subsequent days before and 2, 5, 10, 15, 20, 25, 30, 40, 50 and 60 minutes after rinsing with both solutions. Measurements of pH were done within one hour using a micro pH electrode and a pH meter. All experiments were finished in 6 days by dividing the group to three. Results showed a significant difference between groups in respect to pH values and pH drops after rinsing. Mean pH values were below 5.70 for one hour in sugared solution, whereas no mean pH value was detected below 5.80 for one hour with the sugar-free solution. Minimum pH values (sugar-free: 5.62+/-0.36; sugared: 5.00+/-0.33, p<0.001) and maximum pH drops (sugar-free: -0.57+/-0.26; sugared: -1.16+/-0.44, p<0.001) were also significantly different. No difference was found between genders. We concluded that changing of sucrose to non-acidogenic sweeteners was essential to prevent the cariogenic potential of the pediatric medicines.

Acetaminophen↗
PubMed2006

The heterodimeric sweet taste receptor has multiple potential ligand binding sites.

The sweet taste receptor is a heterodimer of two G protein coupled receptors, T1R2 and T1R3. This discovery has increased our understanding at the molecular level of the mechanisms underlying sweet taste. Previous experimental studies using sweet receptor chimeras and mutants show that there are at least three potential binding sites in this heterodimeric receptor. Receptor activity toward the artificial sweeteners aspartame and neotame depends on residues in the amino terminal domain of human T1R2. In contrast, receptor activity toward the sweetener cyclamate and the sweet taste inhibitor lactisole depends on residues within the transmembrane domain of human T1R3. Furthermore, receptor activity toward the sweet protein brazzein depends on the cysteine rich domain of human T1R3. Although crystal structures are not available for the sweet taste receptor, useful homology models can be developed based on appropriate templates. The amino terminal domain, cysteine rich domain and transmembrane helix domain of T1R2 and T1R3 have been modeled based on the crystal structures of metabotropic glutamate receptor type 1, tumor necrosis factor receptor, and bovine rhodopsin, respectively. We have used homology models of the sweet taste receptors, molecular docking of sweet ligands to the receptors, and site-directed mutagenesis of the receptors to identify potential ligand binding sites of the sweet taste receptor. These studies have led to a better understanding of the structure and function of this heterodimeric receptor, and can act as a guide for rational structure-based design of novel non-caloric sweeteners, which can be used in the fighting against obesity and diabetes.

Amino Acid Sequence↗
PubMed1992

Pedagogical patronizing of the pharmacodynamic promises of illicit drugs.

A review of popular drug education textbooks and curricula indicated most juxtapose the physiologic effects of licitly manufactured drugs under headings representing illicitly prepared drugs. This misrepresentation ignores the literature, which is undivided, in reporting that illicit drugs contain adulterants and substitutes such as: sodium acetate, sodium cyclamate, dolomite, acetaminophen, gypsum, mannitol, inositol, lidocaine, amydricaine, benzocaine, caffeine, ephedrine, intercaine, phenylpropanolamine, piperocaine, procainamide, azopyridine, bromodiphenhydramine, ibuprofen, methaqualone, phenobarital trazodone, acetylcodine, codeine, quinine, quinidine, thallium, arsenic and strychnine. The temptation to extrapolate the results of licitly pure drug lots administered at precisely measured doses to represent the pharmacodynamics of illegally prepared drug lots administered at indiscernible doses must be avoided in drug educational resources. There is a pressing need to correct the factual base, both implied and suggestive, of drug education resources regarding the purity and toxicity of illicitly manufactured and purchased drugs.

Curriculum↗
PubMedDate not supplied

Fructose as a dietary sweetener in diabetes mellitus.

Human beings, including those with diabetes, have a desire for sweetness in the diet that cannot be ignored. The Food and Drug Administration ban of cyclamates and possible ban of saccharin have raised the question of alternative sweeteners for diabetic persons. Considerable interest has been focused on fructose, and both basic and clinical research has delineated its metabolic effects. This paper reviews the characteristics of fructose, as well as its physiology and metabolism in both normal and diabetic man. Findings seems to indicate that, in controlled diabetes, chronic or limited consumption of fructose at moderate doses has no adverse effects on the levels of blood glucose, cholesterol, or tryglycerides.

Adolescent↗
PubMed1988

Factors affecting metabolic activity of the intestinal microflora.

1. The metabolic activity of the gastrointestinal microflora can be modified by numerous factors derived from the host, the host's environment, and the flora itself. 2. Marked differences exist in microbial composition and metabolism of the gut floras of different species of animal, and in the degree of colonization of the various regions of the gut. 3. The microbial flora changes with age, particularly in early infancy, and developmental changes in in vivo metabolism attributable to the gut flora have been noted for methylmercury. 4. Gastrointestinal disease can have a profound effect on microbial colonization and metabolism in the upper regions of the human gut. In particular, hypochlorhydria can lead to elevation in bacterial numbers, and nitrite and nitrosamine concentrations in gastric juice. 5. Environmental factors such as drugs (particularly antibiotics), diet, and xenobiotics can modify microbial metabolism and toxicity of foreign compounds. In some cases exposure to xenobiotics (e.g., cyclamate, rutin) results in metabolic adaptation and increased biotransformation of the foreign compound. 6. By their fermentation of dietary residues and endogenous carbohydrates, the gut bacteria produce acids which can lower lumenal pH and, in turn, modify bacterial enzyme activities. However, the changes in activity appear to be enzyme specific, some increasing with pH and others being inversely related to pH of incubation.

Humans↗
PubMed1990

Intestinal microflora: metabolism of drugs and carcinogens.

The intestinal microflora are capable of performing a wide variety of metabolic transformations. The digestive tract can be exposed to orally ingested, bile excreted, or blood-borne exogenous and endogenous substances that can be converted by the intestinal flora into carcinogens, mutagens, cocarcinogens or tumor promoting agents. In addition, the intestinal microflora can metabolize a wide variety of pharmacological agents resulting in production of metabolites required for the physiological activity of these agents or conversely in the inactivation of these agents. This article reviews the current knowledge of the relationship between the intestinal microflora and the metabolic reactions leading to the transformation of drugs and the production of mutagenic or carcinogenic compounds. The composition and distribution of bacteria in the gastrointestinal tract is discussed and the type of reactions these bacteria perform is summarized. The conversion of specific substrates such as, rutin, digoxin, cycasin, azulfidine and cyclamate are discussed and the physiological implication of these conversions are presented.

Amines↗
PubMed2004

[Profiles of people who return unused medicine to pharmacies in Puy-de-Dôme, and their motivations for doing so].

An unused drug (U.D.) is described as a drug which is purchased, whether according to a prescription or not, but which is not taken. In the past few years, French people have acquired the habit of returning U.D.s to pharmacies. Nevertheless, few studies have been performed to define their typical features and the motivations of these individuals. A descriptive study was carried out in 1/5 of the pharmacies in Puy de Dôme (France) over three 1 week periods between February and June 1998. 377 people (that is, 82% of those who bring U.D. back to the pharmacies) accepted to participate in this study. The main results are as follows: 1. the U.D. are primarily brought back by women (of all ages); 2. these women mainly return U.D. from the family medicine cabinet; 3. the donations result essentially from "the force of habit", "cleaning out the family medicine cabinet" and also, although in lesser proportion, for "humanitarian reasons". This behaviour is contradictory with the communication messages of Cyclamed, the official French association whose mission is to collect drug waste and unused drugs in order to preserve the environment and to promote energy development and valorisation.

Adult↗
PubMedDate not supplied

Susceptibility of nonhuman primates to carcinogens of human relevance.

Nonhuman primates are a valuable experimental model for the evaluation of human carcinogenic risk but have not been widely used for various reasons, such as high cost and lack of availability. The present review discusses the findings from a long-term carcinogenesis study in nonhuman primates that was carried out under contract by the National Cancer Institute from 1961 to 1997. Among the classes of compounds investigated were model rodent carcinogens, food additives, food and environmental contaminants, heterocyclic amines, N-nitroso compounds, and antineoplastic and immunosuppressives. Of the model rodent carcinogens tested, only urethane was carcinogenic in monkeys. Long-term administration of saccharin or cyclamate did not result in toxicity or carcinogenicity in nonhuman primates, which is commonly seen in rodent models. Similar to rodent models and suspected in the human population, the fungal toxins, aflatoxin B1 and sterimatocystin, induced malignant liver tumors in monkeys. Relatively few animals administered DDT developed malignant tumors, however, hepatic and CNS toxicity was commonly observed. Hepatocellular carcinoma developed in a majority of monkeys administered the heterocyclic amine, IQ but not the structurally similar MeIQx. Resultant toxicity and carcinogenicity from N-nitroso compounds was variable. While diethylnitrosamine proved to be the most potent hepatocarcinogen tested, no malignant tumors were seen in animals administered N-methyl-N-nitro-N-nitrosoquanidine. Susceptibility of nonhuman primates to chemotherapeutic agents was also variable. Only procarbazine and N-methyl-N-nitrosourea were highly carcinogenic, whereas few tumors were seen as a result of cyclophosphamide, Adriamycin, melphalan, or azathioprine.

Animals↗
PubMed2000

Chloride channel expression in cultured human fetal RPE cells: response to oxidative stress.

PURPOSE: The human fetal cell line RPE 28 SV4 has been useful for studies of oxidative stress and apoptosis in retinal pigmented epithelium. This cell model is now assessed in functional investigations of chloride channel activity. The study aims to determine the presence of specific chloride channels, including CFTR and ClC channels, to identify the properties of membrane chloride currents and to assess their modulation by hydrogen peroxide, cAMP, and other agents. METHODS: Channel expression was determined using RT-PCR and cDNA cloning and biochemical and immunocytochemical methods. Membrane currents were analyzed using whole-cell, patch-clamp techniques. RESULTS: RT-PCR results confirmed the presence of ClC-5 mRNA, and a full-length clone encoding ClC-3 was isolated from a cDNA library for RPE 28 SV4 cells. Specific staining for CFTR and several ClC channels was detected by immunocytochemistry. Whole-cell chloride currents (under conditions of symmetrical chloride concentrations) averaged 16.9 +/- 3.4 pA/pF (at +100 mV; n = 8), showed outward rectification, and had an anion permeability sequence of Cl(-) > I(-) > cyclamate. Currents were stimulated by cAMP cocktail (250 microM cAMP, 100 microM IBMX, and 25 microM forskolin) and were inhibited by 1 mM DIDS. The oxidative agent hydrogen peroxide (100 microM) decreased the current by 34% +/- 10% (n = 4). CONCLUSIONS. These findings suggest that RPE 28 SV4 cells possess regulated chloride channels including CFTR and members of the ClC chloride channel family. The inhibition of chloride currents by H(2)O(2) suggests that this cell line may be advantageous for studies of chloride channel modulation by oxidative stress.

1-Methyl-3-isobutylxanthine↗
PubMedDate not supplied

[Infrared spectroscopy of the dry residue of liquor crystallograms in various diseases].

The article presents the results of an examination of the dry residue of liquor crystallograms (DRLC) using infrared spectroscopy technique. 36 spectrograms were studied. Elements of similarity and difference were revealed in the spectrograms of organic substance (antifreeze, sodium cyclamate and fatty tissue), of DRLC of the crystal-forming matter CuCl(2)x2H(2)0, of DRLC of a live person and cadaveric liquor (with no brain injury in respective case histories), of DRLC of liquor of live persons with a brain injury, of DRLC of liquor of persons who died of a brain injury and of persons who died of other causes.

Alcoholic Intoxication↗
PubMed2001

[Simultaneous determination of various food additives by high performance liquid chromatography].

A novel method is proposed for the simultaneous separation and determination of eight food additives, acesulfame potassium (AK), aspartame (ASP), benzoic acid (BA), caffeine (CA), saccharin sodium (SA), sorbic acid (SOR), theobromine (TB) and theophylline (TP) by reversed-phase high performance liquid chromatography. The separation was achieved within 23 min by using an Alltech Econosphere C18 column with 10 mmol/L NaH2PO4(pH 4.00)-acetonitrile (90:10, V/V) as mobile phase. The qualification and quantitation were accomplished by using a photodiode array detector. The detection limits (S/N = 3) for all analytes were below mg/L level. Under the experimental conditions, other common food additives and organic acids such as cyclamate, citric acid, malic acid, tartaric acid and ascorbic acid, did not interfere with the determination. The method has been successfully applied to the analysis of various foods as well as pharmaceutical preparation, and the average recoveries for real samples ranged from 78.5% to 107.2%.

Benzoic Acid↗
PubMed2003

[Action of the pharmaceutical industry].

The presence of drugs in the environment, principally in water, can be detected analytically. Although concentrations detected are very low, their presence raises the issue of the impact on the natural medium and human health. In the first part of this review, we attempt to answer some of the most frequently asked questions: why are drugs found in the environment? where do they come from? is there a health hazard? In the second part, we describe measures taken by the pharmaceutical industry to protect the environment. Action is taken to control waste from production sites but also to coordinate the efforts of the pharmaceutical profession via CYCLAMED. Collection and reuse of unused drugs is also discussed.

Drug Industry↗
PubMed2003

[Controversies with aspartame].

INTRODUCTION: Artificial sweeteners are nowadays inevitable food additives, since they provide necessary food diversity to people suffering from diabetes. Aspartame is the most frequently used artificial sweetener ever and its safety profile is much better than that of saccharin or cyclamate. It received marketing approval in 1973, but only 3 months later aspartame was withdrawn because of allegations based on improperly designed experimental studies dealing with its carcinogen effects on rodent brain. However, extensive studies using the same model did not confirm such suspicions, and aspartame received a second marketing approval. EPIDEMIOLOGICAL STUDIES: Almost two decades later an epidemiological study found a relationship between aspartame and an increased frequency of brain tumors in humans. However, this study included a short time span of observation, and it did not estimate actual intake of aspartame, which led to loss of validity. Later on no epidemiological studies found correlation between aspartame use and incidence of brain tumors in humans. Up to now the only safety concern about aspartame, which received valid scientific proofs, is pro-seizure action of its excessive intake. In patients with epilepsy, excessive intake of aspartame can decrease the threshold for seizures or prolong them once they appear. However, if the intake is not above the recommended level of 40 mg/kg b.w./day, aspartame is well tolerated even in this subpopulation. CONCLUSION: Based on detailed analysis of published studies on safety of aspartame, it should not be restricted, but used in recommended amounts.

Animals↗
PubMed1990

Nickel-mediated inhibition in the glutathione-dependent protection against lipid peroxidation.

Glutathione protects liver microsomes against the rapid onset of lipid peroxidation via a sulfhydryl dependent heat labile factor known as free radical reductase. The administration of nickel to mice resulted in an inhibition in the activity of free radical reductase, and enhanced lipid peroxidation and the activity of glutathione S-transferase in a dose dependent manner. The pretreatment of cyclam, a known specific chelator of nickel restored free radical reductase and glutathione S-transferase activities and alleviated nickel mediated enhancement of lipid peroxidation. Our results indicate that nickel-mediated inhibition in free radical reductase activity and activation of glutathione S-transferase may be due to the interaction of nickel with sensitive-SH groups located on these proteins.

Animals↗
PubMed1986

[Contribution of stereochemistry to the study of the spatial organization of pharmacological receptors].

The important discovery by Pasteur of optical isomerism and the recent developments of stereochemistry showed that a complementarity exist between the geometry of molecules and their pharmacological receptors. The stereochemical bases and the principal configurational nomenclatures are briefly overviewed. The stereospecificity of the biological response and theories leading to an approach to stereochemical structures of main pharmacological receptors are developed. So, the biological activity of steroids is due to junctional modes of cycles and alpha or beta configurations of substituents. Acetylcholine has a skew conformation but it react by an anticlinal/anti-planar conformation with muscarinic receptor. To explain the difference in activity of adrenaline enantiomers, Easson and Stedman proposed a "three points" fixation to the adrenergic receptor. Dopaminergic receptor present a good degree of stereoselectivity: dopamine act by an anti-planar conformation in which the N-O distance is the same as in apomorphine (N-O10). The analgesic activity of morphinans is due to a cis junction of B and C cycles and to the stereoelectronic effect of the unshared lone pair on nitrogen. In the cyclamate sweeteners, some authors proposed for the sweet taste receptor a model with two points fixation (one acceptor and one donor) and two spatial barriers located at precise distances from this two sites. The stereoselectivity of molecules acting as substrates or inhibitors of enzymes is described. For example some oxazolidinone derivatives showed a selective inhibition toward monoamine oxidase A. Finally, the pharmacological activity falls often when molecules are administrated in racemic form. It seems that xenobiotics need to be dissymmetric for chiral recognition by biological systems.

Animals↗
PubMed1988

[Ion pair-HPLC of a pharmaceutical multicomponent system].

A multicomponent system of non-ionic (methyl- and propylhydroxybenzoate) and ionic (theophylline, phenobarbital, atropine methobromide, demelverine hydrochloride) analytes, which are applied in therapy as bronchospasmolytically effective drug (Aminophyllin compositum tablets), was investigated by means of ion-pair-HPLC-technique on reversed phases. As ion-interaction-reagents (IIR) were tried alkylsulfonates and sodium cyclamate. The influence of some factors on retention was described. The use of "mixed" IIR for improvement of the separation was investigated.

Aminophylline↗
PubMed1987

Amine N-sulfotransferase.

A highly purified amine N-sulfotransferase has been isolated from guinea pig liver that catalyzes sulfuryl group transfer from 3'-phosphoadenosine 5'-phosphosulfate to one of a large number of either primary or secondary amines forming the appropriate sulfamate and adenosine 3',5'-bisphosphate. Amines as different as aniline, 2-naphthylamine, octylamine, 1,2,3,4-tetrahydroisoquinoline and 1,2,3,4-tetrahydroisoquinoline, desmethylimipramine, and cyclohexylamine serve as acceptors; the product of the last of these substrates is the sugar-substitute cyclamate. Amine N-sulfotransferase activity is dependent on the presence of an unprotonated amino group. The purified enzyme preparation also has O-sulfotransferase activities, suggesting that transfer to oxygen could represent an intrinsic function of the N-sulfotransferase.

Animals↗
PubMedDate not supplied

Reverse-phase liquid chromatographic determination of benzoic and sorbic acids in foods.

An isocratic liquid chromatographic (LC) technique is described for the determination of benzoic acid and sorbic acid in foods such as beverages, fruits, seafood, vegetables, sauces, and dairy, bakery, and confectionery products. A C18 column is used with methanol-phosphate buffer (5 + 95) as mobile phase and 4-hydroxyacetanilide or 3,5-dinitrobenzoic acid as internal standard. Sample preparation is simple, rapid, and produces a sample extract that has a minimum effect on the column performance and life. Specificity of the method was checked against common food additives such as L-ascorbic acid, caffeine, artificial sweeteners (saccharin, cyclamate, aspartame), antioxidants (BHT, BHA) and artificial colors. Also described are 2 procedures for confirmation of the preservatives, using either redox reaction of sorbic acid with potassium permanganate or gas chromatography/mass spectrometry. Mean recoveries of 90-105% were obtained with a precision of 1-6% and a detection limit of 20 mg/kg for the 2 preservatives.

Benzoates↗