Biomedical subjects

L Campanella

Publications and source records attributed to L Campanella.

At least 37 records · Page 2Linked to original sources

PubMed2001

Evaluation of radical scavenging properties of several plants, fresh or from a herbalist's, using a superoxide dismutase biosensor.

The experimental evaluation of properties of defence against free radicals represents an extremely interesting heuristic and applicational objective. Research was carried out to experimentally evaluate the scavenging properties of several fruits and plants, fresh or from a herbalist's using an amperometric superoxide dismutase (SOD) biosensor recently developed by the present authors. The superoxide radical was produced in solution using the xanthine/xanthine oxidase system; measurements were carried out by comparing biosensor response to superoxide radical both in the presence and absence of the sample considered.

Biosensing Techniques↗

PubMed2001

Two OPEEs (organic phase enzyme electrodes) used to check the percentage water content in hydrophobic foods and drugs.

The development and optimization of an analytical method using enzymatic biosensors able to operate in organic solvents [organic phase enzyme electrodes (OPEEs)] for the determination of the water content in food fats (butter, margarine) or pharmaceutical or cosmetic ointments is described. The method is based on the increase in enzymatic activity which is related to the increase in the percentage water content in the organic phase into which the biosensor is dipped. The enzymes used to assemble the biosensors were tyrosinase or catalase, the substrates were phenol or p-cresol and tert-butyl hydroperoxide, respectively, and the organic solvents were acetonitrile or dioxane. A gas diffusion amperometric electrode for oxygen measurement was used as electrochemical transducer. The results were compared with those obtained applying the Karl Fischer method to the same food or drug matrices. The correlations among the two methods proved satisfactory, as the difference in the computed values of water content was never higher than 7%. Also, the precision of measurements was acceptable (RSD < 6%) in all the analyses of real matrices.

Biosensing Techniques↗

PubMed2000

New biosensor for superoxide radical used to evidence molecules of biomedical and pharmaceutical interest having radical scavenging properties.

A superoxide dismutase biosensor was used to determine the antioxidant properties of scavenger molecules and the antiradical activity of healthy and diseased human kidney tissues; this biosensor is based on the use of the enzyme superoxide dismutase (SOD), which is physically entrapped in a kappa-carrageenan gel membrane, and of a transducer consisting of an amperometric hydrogen peroxide electrode. Several compounds with scavenging properties were tested, including some commercial drugs.

Biosensing Techniques↗

PubMed2000

Flow injection analysis of cholic acids in pharmaceutical preparations using a polymeric membrane ISE as detector.

The results reported in this paper regard the setting up of a polymeric membrane ISE that is selective for cholic acids (CA) and able to work in a flow system, especially in flow injection analysis (FIA), based on the exchanger (tetrakisdecylammoniumcholate, TDACh), which has proved effective, is of very simple but suitable structure and is above all easy to synthesise starting from commercially available chemicals. A complete analytical characterisation of the sensor was performed working both in batch conditions and in FIA, using in the latter case a 'wall jet' type of flow cell. The response toward different bile acid sodium salts such as the CA, deoxycholic (DCA), chenodeoxycholic (CDCA), ursodeoxycholic (UDCA), taurocholic (TCA) sodium salts was checked. The application to the analysis of different commercial drugs by FIA was also performed to determine the UDCA or CDCA acid content of several pharmaceutical formulations. Lastly, a preliminary study is presented concerning the use of the investigated electrochemical sensor as high performance liquid chromatography (HPLC) detector.

Cholic Acids↗

PubMed1999

Simultaneous determination of cysteine, cystine and 18 other amino acids in various matrices by high-performance liquid chromatography.

An extraction protocol and a reversed-phase high-performance liquid chromatographic method for the simultaneous determination of cysteine, cystine and 18 other amino acids in biological and vegetable samples are described. Among the different methods proposed for amino acid determination, phenylisothiocyanate was used as the reagent for derivatization. Chromatograms obtained in the analysis of standard solutions and actual samples are reported, together with regression equation, correlation coefficient (> 0.999 for all), limit of detection and recoveries (between 86 and 102% for all the examined matrices) for each amino acid. Practical protocol and method applications in normal patients and patients affected by different pathologies, and in algal products are discussed.

Amino Acids↗

PubMed1998

Hydrogen peroxide determination in pharmaceutical formulations and cosmetics using a new catalase biosensor.

The possibility of evaluating the content of hydrogen peroxide in several authentic matrices, such as cosmetic and pharmaceutical formulations, was studied. A new catalase biosensor fabricated using an amperometric gas-diffusion oxygen sensor as electrochemical transducer and the catalase enzyme immobilized in kappa-carrageenan gel and capable of operating in both aqueous and non aqueous solvents was developed and tested for this purpose. Creams, emulsions and disinfectant solutions were analysed. To this end, a preliminary check was needed to establish the best conditions to analyse these matrices; the choice of solvent was one of the most important points studied. The solvents considered included dioxane, water-dioxane mixtures, water saturated chloroform and aqueous solutions. The different solubility properties of the matrices analysed were taken into account.

Biosensing Techniques↗

PubMed1998

Lidocaine and benzalkonium analysis and titration in drugs using new ISFET devices.

Two new ISFETs recently developed by us have now been applied to some pharmaceutical determinations in real matrices; the first device, responsive to cationic surfactants, was employed in the determination of benzalkonium chloride contained in two different disinfectant solutions and in three types of commercial collyrium; the second device, responsive to cocaine hydrochloride, showed an appreciable response also to lidocaine hydrochloride and was used in the determination of lidocaine hydrochloride contained in some injectable antibiotics. The repeatability and accuracy of measurements performed in the analysis of these pharmaceutical matrices using new solid state sensors were evaluated. A further aspect of the research involved the use of two sensors to record complete titration curves for the determination of benzalkonium chloride, cocaine hydrochloride and lidocaine hydrochloride, respectively. Applications to real matrices were also performed by analysing by titration pharmaceutical formulations containing benzalkonium chloride, or lidocaine hydrochloride and an illicit powder containing cocaine hydrochloride and sugars.

Benzalkonium Compounds↗

PubMed1998

Analysis of lecithin in pharmaceutical products and diet integrators using a new biosensor operating directly in non aqueous solvent.

One of the first examples of a bienzymatic organic phase enzyme electrode (OPEE) is described. It was obtained using two enzymes (phospholipase D and choline oxidase), both immobilised in kappa-Carrageenan gel and, as electrochemical transducer, an amperometric gas diffusion electrode for oxygen. The response of the biosensor was recorded and its sensitivity, linearity range, response time evaluated. Lastly drugs and diet products containing lecithin were analysed using the new biosensor device working in an organic mixture.

Alcohol Oxidoreductases↗

PubMed1997

Antimitotic effects of usnic acid on different biological systems.

Usnic acid is a biosynthesis product characteristic of several epiphytic lichens such as Evernia, Cladonia and Parmelia. Usnic acid has several interesting biological properties. It is an antibiotic and it also seems to exert an antimitotic action. It has even been postulated that usnic acid can play a role as an environmental indicator, since its concentration varies according to the presence of toxic agents. A series of tests have been run on different biological systems such as fungi, yeasts, plant cells and neoplastic human cell cultures in order to make a general evaluation of the properties of usnic acid and to highlight any analogy between its effects on phylogenetically distant organisms. The results obtained confirm some of the already known properties of usnic acid and identify concentration ranges that are active against cells from different organisms. Furthermore, at low concentrations, the acid displays a capacity to stimulate cell metabolism in some of the biological systems tested.

Adenocarcinoma↗

PubMed1996

Genetic damage in urban mice exposed to traffic pollution.

Wild rodents (Mus domesticus) were collected in three areas in Rome exposed to different traffic flows to ascertain a possible correlation between genetic damage and heavy metal concentration. The concentration of lead, cadmium and zinc were determined in liver, kidney and bones and two mutagenicity tests (micronucleus test and sperm abnormality assay) were employed. The results obtained showed that the contents of lead and cadmium were higher in animals collected in areas with high traffic flows than in those from control areas. A statistically significant increase of the frequency of micronucleated erythrocytes and of abnormal sperm cells was also obtained in animals collected in sites with high traffic flows. The investigation confirmed the suitability of using wild rodents as bioindicators of environmental pollution and as key-organisms in programs of pollution monitoring and environmental conservation.

Journal Article↗

PubMed1996

Toxicity order of cholanic acids using an immobilised cell biosensor.

There is considerable published evidence of the use of cells of various species to evaluate the toxicity of numerous compounds, many of pharmaceutical interest. The coupling of cell colonies with a suitable transduction device has led to the development in recent years of toxicity biosensors based on the alteration of a process or a cell metabolic function by the toxic substance under examination. A biosensor based on immobilised yeast cells (Saccharomyces cerevisiae) has been developed recently in this department for the purpose of performing a rapid toxicity test in aqueous environmental matrices. This biosensor has now been used in the toxicity screening of a number of sodium salts of conjugated and free cholanic acids. The "toxicity degree" scale, which was found by placing in decreasing order the values of the slopes of the straight lines obtained by quantifying changes in the behaviour of the respirometric curve, plotted before and after incubation, using known concentrations of cholanic acid sodium salts, was: deoxycholic acid > chenodeoxycholic acid > ursodeoxycholic acid > cholic acid, for free cholanic acids; and glycodeoxycholic acid > glycochenodeoxycholic acid > glycocholic acid, for glycocholanic acids. These values are in good agreement with published toxicity data obtained in vitro. This sensor can thus be considered to provide a valid instrument for the preliminary evaluation of the toxicity of organic compounds or drugs.

Biosensing Techniques↗

PubMed1996

Comparison of three analytical methods for cocaine analysis of illicit powders.

A new cocaine-sensitive ISFET device based on a cocaine-reineckate ion-pair complex dispersed in a PVC--sebacate matrix has been fabricated. this sensor displays a linear range for cocaine hydrochloride between about 3 x 10(-6) and 2 x 10(-2) M and a fast response (< or = 25 s), which remains almost constant over the pH range 3-7. The sensor has been applied to the analysis of authentic illicit powders containing cocaine hydrochloride and other substances commonly associated with it, or of cocaine free base (crack). Experimental results were compared with those obtained employing two more common instrumental methods of analysis: gas chromatography (GC), and UV absorption spectrometry (the latter applied directly or based on second derivative absorption spectroscopy). Good agreement was found between results obtained by ISFET and GC methods, while UV absorption spectrophotometry proved suitable only in the case of pure cocaine hydrochloride and free base, or in samples also containing lidocaine, but using second derivative absorption spectroscopy.

Chromatography, Gas↗

PubMed1995

Immobilised yeast cells biosensor for total toxicity testing.

An immobilised yeast cell biosensor has been developed for the total toxicity testing of a sample that may contain a number of different pollutant species; the biosensor uses an amperometric gas diffusion oxygen as indicator electrode. The method is based on the perturbation of the respiratory activity of a yeast, Saccharomyces cerevisiae, immobilised on an agar gel containing the culture medium (i.e., 'agarised medium'), by the toxic test substance. Glucose is used as substrate while the toxic substances tested consist of several metallic ions, phenol and cationic or anionic surfactants.

Biosensing Techniques↗

PubMed1995

A complex of microperoxidase with a synthetic peptide: structural and functional characterization.

This paper reports the kinetic and thermodynamic characterization of the complex obtained by binding to microperoxidase (the heme-containing undecapeptide derived from peptic hydrolysis of cytochrome c) a 13 residues synthetic peptide with some propensity to acquire alpha-helical secondary structure (P13). Our results indicate that P13 binds to the sixth coordination position of the Fe(III) of microperoxidase (Keq = 4.8 x 10(4) M-1 at pH 7.0 and 25 degrees C) via the imidazole of His-12, forming a stable complex. The kinetics of complex formation, its secondary structure and its electrochemical activity are reported. This is a first step towards engineering a miniature-heme complex, for a better understanding of the mechanisms governing electron transfer in hemes and heme-proteins, and possibly for novel biotechnological applications.

Amino Acid Sequence↗

PubMed1995

Aspartate analysis in formulations using a new enzyme sensor.

A biosensor has been developed for the purpose of directly analysing aspartate in pharmaceutical formulations and aspartame in sweeteners. This biosensor consists of an ammonia-sensitive gas-diffusion electrode and the enzyme L-aspartase immobilized by means of polyazetidine on a dialysis membrane.

Aspartame↗

PubMed1995

A new salicylate ISFET for the determination of salicylic and acetylsalicylic acid in drugs.

A salicylate ISFET for the analysis of salicylic and acetylsalicylic acid in drugs is described. It is based on a salicylate ion selective membrane coated on the surface of the Si3N4 gate of the FET. The sensitive membrane consists of tetra-dodecylammonium salicylate, polyvinyl chloride and a proper plasticizer. The linearity range of the sensor is 5 x 10(-5)-1.5 x 10(-2) M for the salicylic acid, and 7 x 10(-5)-1.5 x 10(-2) M for the acetylsalicylic acid, respectively. The detection limit for the two compounds is 5 x 10(-5) M while the response time is < or = 20 s. The effect of pH and different interfering ions was also studied. The sensor was used to analyse the content of acetylsalicylic and salicylic acid in some drugs, and the accuracy of the method was evaluated through recovery tests. The results obtained with this method are well correlated either with those obtained with a classical ISE employing the same sensitive membrane or with the classical volumetric method.

Aspirin↗

PubMed1993

Biosensor for direct determination of glucose and lactate in undiluted biological fluids.

This paper describes the implementation of a bienzyme sensor for the direct determination of glucose and lactate in undiluted biological samples. The biosensor exploits the competitive action versus the substrate itself by two different enzymes immobilized into a sandwich of two different membranes. In this way the quantity of substrate reaching the indicating electrode is reduced and this determines an extension of the linearity range.

Biosensing Techniques↗

PubMed1991

Use of 'solid-state' promoters in the electrochemistry of cytochrome c at a gold electrode.

The direct electrochemistry of cytochrome c at a gold electrode was investigated by cyclic voltammetry using, as promoters, microperoxidase (the haem-undecapeptide obtained by hydrolysis of cytochrome c), Fe(III)-protoporphyrin IX or protoporphyrin-IX, all entrapped in a cellulose triacetate membrane. The results indicate that these immobilized systems strongly enhance the rate of electron transfer between the protein in solution and the electrode surface, and thus behave as 'solid-state' promoters, though with differing efficiencies. These results are of interest because they raise the possibility of engineering an efficient and versatile promoter active also at inert electrode surfaces.

Animals↗