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Biomedical subjects

S Fanali

Publications and source records attributed to S Fanali.

At least 73 records · Page 4Linked to original sources
PubMed1995

[The presence of Actinobacillus actinomycetemcomitans in subgingival bacterial plaque in relation to the amount of supragingival plaque].

Actinobacillus actinomycetemcomitans (Aa) is currently considered the principal bacterium involved in juvenile forms of periodontitis. Considering that supragingival and subgingival plaque are closely correlated, the aim of the present research has been to assess if a correlation can be recognized between the amount of supragingival plaque and the presence of Aa in subgingival plaque in young subjects. Thirty-three individuals participated in the study. In each subject's dentition two periodontal sites were chosen: one (test site) was randomly selected among those sites which displayed a Plaque Index (P1I) = 0; another site was similarly chosen among those which presented the highest P1I score (2 or 3). In each test and control site Gingival Bleeding Index (GBI) was recorded and a microbiological sampling of subgingival plaque was performed. After anaerobic culture of plaque samples, the occurrence of Aa in each test and control site and the proportional representation of the bacterium in total cultivable anaerobic flora were assessed. Results showed a statistically significant difference in the occurrence of Aa between test and control sites in the same oral cavity and a correlation between GBI positivity and Aa presence. In conclusion, according to other authors, Aa seems to be more frequently founded in subgingival plaque coming from periodontal sites where supragingival plaque in more abundant.

Adolescent↗
PubMed1995

[Stereoselective analysis of pharmaceutical compounds in biological fluids with capillary electrophoresis].

Biological fluids drugs analysis are important to investigate the pharmacokinetic and pharmacodynamic of the subministered compounds for the comprehension of their behaviour and bioavailability. Many pharmaceutical preparations contain a chiral molecule as active compound often as racemic mixture of the two enantiomers of which only one exhibits pharmacological effect, the other enantiomer being inactive or responsible of toxicological effects. In fact two enantiomers with almost identical physical and chemical properties can exhibit a different behaviour in an highly stereoselective environment as the human body. With respect to the analytical methods in use for chiral separation Capillary Electrophoresis shows high efficiency and resolution together with feasibility, low costs and very short analysis time. CE and MEKC have been used for enantiomers resolution of antihypertensive and anticoagulant drugs in body fluids. By cyclodextrin modified MECK the separation of mephenytoin and 4-hydroxymephenytoin metabolite in urine samples has been performed in order to identify different phenotypes in the oxidative metabolising ability in man.

Animals↗
PubMed1994

Improved separation of diastereomeric derivatives of enantiomers by a physical network of linear polyvinylpyrrolidone applied as pseudophase in capillary zone electrophoresis.

Diastereomeric analytes were separated using capillary zone electrophoresis with polyvinylpyrrolidone as polymeric additive to the buffer solution. As test substances derivatives of D- and L- alpha-amino and alpha-hydroxy acids formed by reaction with (+)-O,O'-diacetyl- and (+)-O,O'-dibenzoyl-L-tartaric anhydride, respectively, were used. The physical network formed by the linear polymer is supposed to act as a kind of pseudophase. It was found that the network affects the mobility of diastereomeric compounds to a different extent, enhancing the selectivity of the system. In nearly all cases of aromatic acids the diastereomer carrying the D-amino acid was more strongly retained than the L-isomer, as opposed to the situation with aliphatic acids.

Amino Acids↗
PubMed1994

Separation of alpha-hydroxy acid enantiomers by high performance capillary electrophoresis using copper(II)-L-amino acid and copper(II)-aspartame complexes as chiral selectors in the background electrolyte.

Optical isomers of some alpha-hydroxy acids, namely 2-, 3-phenyllactic acid, mandelic, p-hydroxy-, m-hydroxy and 3,4-di-hydroxymandelic acid, were separated by means of capillary zone electrophoresis in free solution, using copper (II) complexes with L-amino acid or aspartame ligands in the background electrolyte. The concentration and the pH dependence of the enantiomer separations have been studied in the cases of different chiral ligands and/or analytes. With the use of L-proline as ligand only the optical isomers of 3-phenyllactic acid were resolvable, whereas using L-hydroxyproline the D and L forms of all compounds, except for 2-phenyllactic acid, were separated. Better results were obtained with aspartame as chiral ligand.

Amino Acids↗
PubMed1994

Analysis of mephenytoin, 4-hydroxymephenytoin and 4-hydroxyphenytoin enantiomers in human urine by cyclodextrin micellar electrokinetic capillary chromatography: simple determination of a hydroxylation polymorphism in man.

Using cyclodextrin micellar electrokinetic capillary chromatography (CD-MECC), baseline separation of mephenytoin, 4-hydroxymephenytoin and 4-hydroxyphenytoin enantiomers in urine was effected with beta-cyclodextrin. After single-dose administration of 100 mg of racemic mephenytoin, the 0-8 h urine was collected, and enzymatically hydrolyzed urine specimens were applied. For extensive metabolizers, a single peak for 4-hydroxymephenytoin was detected corresponding to the S-enantiomer. This peak was either very small or undetectable in samples of poor metabolizers. Typically, mephenytoin could not be detected in these samples. However, application of undeglucuronidated extracts revealed the presence of free S-4-hydroxymephenytoin and R,S-mephenytoin and thus permitted phenotyping via both the urinary S:R enantiomeric ratio of mephenytoin and the hydroxylated metabolite. Application of enzymatically hydrolyzed and extracted urines after phenytoin administration (100 mg; 0-8 h urine collection) revealed the presence of S-4-hydroxyphenytoin. Thus, CD- MECC is shown to be a simple and attractive approach for (i) the confirmation of the stereoselectivity of the aromatic hydroxylation of mephenytoin and phenytoin, (ii) the simple and rapid differentiation between extensive and poor metabolizers for mephenytoin, and (iii) assessment of compliance.

Buffers↗
PubMed1994

Consequences of a maximum existing in the dependence of separation selectivity on concentration of cyclodextrin added as chiral selector in capillary zone electrophoresis.

The maximum in the dependence of the separation selectivity on the concentration of cyclodextrin may be utilized for the determination of the mean value of host-guest interaction constants of the separated enantiomers. For the hosting of N-t-BOC-DL-tryptophan by beta-cyclodextrin, the mean value of these constants, found by drop line estimated from the cyclodextrin concentration corresponding at the maximum, is 350 L.mol-1. The separation at this concentration of cyclodextrin offers the highest resolution in the shortest separation time. It is shown that commonly used simple preliminary experiments, testing the capability of a cyclodextrin to resolve chiral compounds, and based on relatively high cyclodextrin concentrations, may easily lead to incorrect conclusions in cases of enantiomers strongly interacting with the cyclodextrin used.

Cyclodextrins↗
PubMed1992

Micellar electrokinetic chromatographic study of hydroquinone and some of its ethers. Determination of hydroquinone in skin-toning cream.

The separation of hydroquinone and some of its ether derivatives was studied by micellar electrokinetic chromatography with sodium dodecyl sulphate as an anionic surfactant in the background electrolyte. The optimized method was used for the determination of hydroquinone in a sample of skin-toning cream. On-column detection at 254 nm with caffeine as an internal standard gave good quantitative results.

Caffeine↗
PubMed1991

Application of capillary zone electrophoresis to the characterization of multiple antigen peptides.

Capillary zone electrophoresis (CZE) was applied to the analysis of a recently described class of synthetic branched peptides, multiple antigen peptides (MAPs). In comparison with high-performance liquid chromatography (HPLC), CZE showed superior resolution of minor impurities in samples of MAPs obtained by preparative chromatography. MAPs that differed only in the substitution of uncharged residues (Ala-Ser) could be separated by the addition of organic solvents (acetonitrile, methanol, ethanol) to the aqueous background electrolyte.

Amino Acid Sequence↗
PubMed1991

Capillary zone electrophoresis and mass spectrometry for the characterization of genetic variants of human hemoglobin.

This paper describes a simple and rapid analytical method for the structural identification of abnormal human hemoglobins. Globin chains obtained by precipitation of erythrocyte hemolysate in cold acetone are directly analyzed by capillary zone electrophoresis in coated capillaries without any prior treatment. The speed and the high resolving power of capillary zone electrophoresis allow fast differentiation of hemoglobins with similar charges. Capillary zone electrophoretic tryptic mapping has also been performed for each globin, so that complete variant characterization can be achieved by direct comparison of the variant tryptic map with the corresponding normal one. Coupling electrophoretic data with analysis of enzymatic digests by mass spectrometry according to the "fast atom bombardment mapping" procedure makes it possible to quickly identify amino acid variations. This paper describes how the method can be applied to the characterization of common and uncommon variants and underlines the advantages and limitations of the procedure along with its potential uses in structural analysis of proteins.

Chromatography, High Pressure Liquid↗
PubMed1991

[An embryological analysis of the variation in the lipid content of the dental pulp at different developmental stages].

The authors have considered the per cent differences of lipidic content in Bos taurus dental pulp taken from differently aged animals. The studies have been carried out on 6-7 months fetus, on 1-2 years old animals (deciduous erupted tooth and developing non erupted permanent teeth) and on 8-10 years old animals. Moreover the percentages of free and esterified cholesterol, fatty free acids, triglycerides as well as different phospholipids have been calculated.

Aging↗
PubMed1991

[The embryological development of the nerve fibers of the tooth. An analysis of their formation and development correlated with the different evolutionary stages of the dental structures].

In this review the research on the growth and development of nerve fibers in the dental pulp have been summarized. The first part present the distribution, type, morphology and way of impulse transmission as well as the role of the pulpal nerves. The second part present the growth of the nerve fibers in the dental structures. Through the analysis of all the research done on this subjects two important thighs can be deduced: the developing innervation correlates with the stage of the development of individual teeth rather than the chronological age of the animal, and the dental pulp compared to other structures is relatively late in maturing. This is why the axons don't penetrate into the dental papilla until crown formation commences. Then the probable role of the pulpal nerves in tooth growth (dentinogenesis) has been analysed, but this activity, even though unessential, is evident only in developing final phases and not in the early ones; this is why the axons are separated from the early growing tissues. Concluding, our review shows the variation in number, type and function of the pulpal nerves from their developing period to their complete formation until senescence.

Dental Pulp↗
PubMed1990

Applicability of dynamic change of pH in the capillary zone electrophoresis of proteins.

A method to extend the separation power of CZE is described. The method is based on the separation of sample components at two different pH values during one separation run, and involves dynamic buffering of the pH inside a separation capillary by controlling the flow of H+ ions from the anodic electrode chamber. By changing the anolyte in the chamber, a dynamic pH step is generated, which proceeds rapidly along the capillary and establishes the required new pH value. The use of the method has been demonstrated by the cationic separation of a model mixture of proteins.

Animals↗
PubMed1990

Capillary zone electrophoresis in pharmaceutical analysis.

The paper presents a brief characterization of capillary zone electrophoresis, a modern analytical separation method with high expediency for practical applications, especially in pharmaceutical analysis. Basic theoretical considerations are presented and discussed to explain the effects of the operational parameters upon the separation efficiency and resolution of species. Descriptions of simple instrumentation and of the analytical procedure itself are given. Experimental examples are given of the separation of mixtures of pharmaceutically important compounds and of the effects of operational parameters, especially pH of BGE and voltage applied. Lastly, the practical application of CZE for analysis of isoxsuprine in commercial preparations is shown.

Electrophoresis↗
PubMed1990

Enantiomer resolution by using capillary zone electrophoresis: resolution of racemic tryptophan and determination of the enantiomer composition of commercial pharmaceutical epinephrine.

The enantiomers of D- and L-tryptophan were separated by capillary electrophoresis, using alpha-cyclodextrin as a chiral active component in the background electrolyte. The separation of (-) and (+) epinephrine was achieved by supplementing the background electrolyte with Heptakis (2,6-di-O-methyl-beta-cyclodextrin). As a practical application of the method, the quantitative analysis of (-) and (+) enantiomers in commercial pharmaceutical solutions of adrenaline is shown.

Cyclodextrins↗
PubMed1990

Capillary zone electrophoresis of rare earth metals with indirect UV absorbance detection.

The separation of 14 lanthanides by capillary zone electrophoresis was studied in the background electrolyte containing hydroxyisobutyric acid as complexing counter-ion and creatinine as a UV absorbing coion for indirect detection of lanthanide zones. A complete separation was achieved in less than 5 min and the applicability of the method for the analysis of real samples was demonstrated.

Creatinine↗
PubMed1990

[A comparative evaluation of oral and parenteral cephalosporins in inhibiting the growth of bacteria pathogenic to the periodontium].

A study was carried out in vitro to assess the inhibitory activity on the growth of Bacteroides gingivalis and Bacteroides intermedius using two oral cephalosporins (Cephalexin and Cephradine) in comparison to two parenteral cephalosporins (Cefotaxime and Ceftriaxon) and the classic Tetracycline HCl. The results of the study show that the inhibitory activity on the growth of the two periodontopathogenic bacteria produced by the oral cephalosporins is comparable to that of other antibiotics studied, and that in comparison to parenteral cephalosporins the former have the advantage of being better accepted and more economic.

Administration, Oral↗