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Biomedical subjects

F M Rubino

Publications and source records attributed to F M Rubino.

16 recordsLinked to original sources
PubMed2006

Aluminum determination in biological fluids and dialysis concentrates via chelation with 8-hydroxyquinoline and solvent extraction/fluorimetry.

We describe a simple, rapid, and sensitive fluorescence method for measurement of aluminum (Al) in human biological fluids, in dialysis solutions, and in tap water, which uses 8-hydroxyquinoline for ion chelation. The fluorescence intensity of the toluene-extracted metal chelate (excitation wavelength, 380 nm; emission wavelength, 504 nm) remains unchanged for over 48 h at room temperature. Fluorescence intensity is a linear function of the concentration of Al in the 2-1000 microg/L range with detection limits of 0.7-2 microg/L. A large excess of other ions normally found in biological fluids does not interfere in Al determination. The method developed was successfully used in assaying Al in serum and urine of reference subjects, in serum samples from patients undergoing long-term dialysis, and in dialysis solutions. Al concentrations, measured by this fluorimetric procedure, were compared with those obtained by Zeeman graphite-furnace atomic absorption spectrometry. A correlation coefficient of 0.98 was obtained. The proposed method could be used for routine analysis in clinical laboratories for accurate determination of aluminum in aqueous or biological fluids.

Aluminum↗
PubMed2001

Separation methods for methotrexate, its structural analogues and metabolites.

Methotrexate (MTX) is the prototype folate antagonist cytotoxic drug, employed in the therapy of solid tumors and leukaemias, and recently also as an immunosuppressive agent in organ transplantation, in the treatment of some autoimmune diseases and in the therapy of severe asthma. MTX is one of the very few antineoplastic drugs the therapeutic concentration monitoring of which is currently employed in clinical practice and can be routinely measured in biological samples by a number of different analytical techniques, among which are immunoenzymatic and chromatographic methods. Each technique has of course its own advantages in terms of sensitivity, specificity, speed, cost and level of expertise required. Along with therapeutic drug concentration monitoring and clinical pharmacology, fundamental research into the mechanism of action of antifolate drugs is still a field which requires the measurement of MTX, of its new analogues and of their metabolites in biological samples. This review summarizes the instrumental conditions and the performance of several published chromatographic methods employed to measure MTX, its metabolites and some analogues in clinical and biological research. More than 70 papers describing chromatographic assays for MTX and its metabolites have been published in the literature between 1975 and 2000. A wide array of experimental conditions for sample preparation, analyte separation and detection have been employed. According to their chemical properties, MTX, its metabolites and analogue drugs present in several biological samples (plasma, serum, saliva, urine, cerebrospinal fluid, tissue specimens) can be extracted, separated and detected under a variety of chromatographic conditions, i.e. on different stationary phases, under a wide choice of mobile phase conditions (acidic or neutral, employing ion-pair or micellar chromatography), followed by several detection techniques (UV-Vis spectrophotometry, pre- or post-column oxidation and fluorimetry, electrochemistry, mass spectrometry). Optimized methods allow simultaneous measurement within a few minutes of the plasma levels of MTX and its main metabolites at concentrations in the low-nM range. One special field which needs sensitive, fast and inexpensive methods for the detection and measurement of MTX is the monitoring of contamination in workplace environments, such as pharmaceutical industries and oncological hospital pharmacies, and in sewage waters. The measurement of the intracellular gamma-oligo-glutamate metabolites of biological folates, of MTX and of some analogue drugs is of great importance in basic pharmacological research. The existence of empirical quantitative relationships between the retention of individual oligomers under different chromatographic conditions and the number of added glutamic acid units allows identification of the metabolites even when authentic standards are not available.

Folic Acid Antagonists↗
PubMed1999

High-performance liquid chromatography of methotrexate for environmental monitoring of surface contamination in hospital departments and assessment of occupational exposure.

In the frame of applicative research in occupational hygiene of hospital workplaces, we investigate hospital indoor contamination as a consequence of the use of antineoplastic drugs (ANDs), with the purpose of assessing exposure of medical and nursing personnel to potentially harmful doses of ANDs, and ultimately of yielding advice on safe operating procedures for manipulation of ANDs in hospitals and in house-care of cancer patients. Among the large number of currently employed ANDs, methotrexate (MTX) has been selected as a tracer of surface contamination, on the basis of its wide use in therapy, its ease of measurement and of its chemical properties relevant to persistence and transport in the indoor environment. MTX is a polyelectrolyte, with a high water, but lower organic solvent solubility, a negligible vapour pressure and a high chemical robustness to environmental stress, thus allowing to measure surface-to-surface carryover (e.g. from spillage or glove fingerprint) and indoor contamination due to aerosol transport (e.g. from syringe manipulation procedures). Monitoring of MTX in environmental samples such as swab washings of surfaces and objects requires an analytical method with characteristics of sensitivity, reproducibility, precision, analytical speed, ease of automation and robustness. We have therefore developed an analytical procedure which employs simple short-column RP-HPLC with UV detection, automated sample injection and a close analogue internal standard for improved precision and solid-phase extraction (SPE) for sample concentration. Our method has proven suitable for detecting traces of MTX on a wide variety of surfaces and objects, with a limit of quantification in the range of 50 microg/dm3 for direct injection of unconcentrated washings, corresponding to the possible detection of surface contamination as low as 1 microg/m3 and a limit of detection in the range of 10 ng/m2 for samples as large as 100 dm3 concentrated by SPE. We present preliminary results from a recent hospital case-study, assessing the contamination level of furniture and equipment in drug preparation areas. Spillage fractions as high as 5% of the employed mass (70-260 mg/day) are measured on the polythene-backed paper disposable hood cover sheet; traces of MTX in the microgram range can also be measured on floor surfaces, furniture and handles, even at a distance from the preparation hoods.

Antimetabolites, Antineoplastic↗
PubMed1999

Measurement of surface contamination from nucleoside analogue antineoplastic drugs by high-performance liquid chromatography in occupational hygiene studies of oncologic hospital departments.

Within the frame of a continuing interest in occupational hygiene of hospitals as workplaces, we describe an automated analytical method by reversed-phase high-performance liquid chromatography for the measurement of contamination from the three most important nucleoside analogue antineoplastic drugs (5-fluorouracil, 5FU; cytarabin, CYA; gemcytabin, GCA) on such surfaces as those of preparation hoods and work-benches in departmental pharmacies of oncologic departments. Our method is characterized by a short analysis time (7 min) under isocratic conditions, by the use of a mobile phase devoid of organic solvent and by high sensitivity (LOD > or = 40 micrograms/l for all compounds), adequate to detect surface contamination above a threshold of 4 micrograms/m2 for wide surfaces and of 30 micrograms/m2 for small irregular objects. We present some results from a preliminary survey study recently performed in seven oncologic departments of two large general hospitals in Milan. To exemplify the contamination levels on various surfaces (such as on handles, floor surfaces and window glass panes, even far from the preparation hood), analyte concentrations in the order of 0.03-0.06 microgram/ml, corresponding to 0.8-1.5 micrograms of 5FU were measured on telephones, of 0.02-0.6 microgram/ml (0.85-28 micrograms/m2) of CYA were measured on table boards, of 0.05-10.6 micrograms/ml (1.2-1150 micrograms/m2) of GCA on furniture and floors. Spillage fractions up to 1% of the employed ANDs (employed daily 5FU 7-13 g; CYA 0.1-7.1 g; GCA 0.2-5 g) are measured on the polyethylene-backed paper disposable cover sheet of the preparation hood.

Antineoplastic Agents↗
PubMed1992

Application of triple quadrupole tandem mass spectrometry to the analysis of pyridine-containing derivatives of long-chain acids and alcohols.

An improved derivatization procedure for the preparation of nicotinate and 3-picolinyl esters from mixtures of fatty alcohols and acids has been developed. The derivatives can be analysed by capillary gas chromatography on an SE-54 type column, which affords separation of the acid and alcohol derivatives with the same carbon chain. Detection with tandem mass spectrometric techniques on a triple quadrupole instrument is feasible, and yields informative spectra devoid of coeluting interferences.

Chromatography, Gas↗
PubMed1992

Characterization of putative neurotransmitter N-acetyl-aspartyl-glutamic acid and some related compounds by fast atom bombardment and tandem mass spectrometry.

The characterization of the N-blocked neuropeptide N-acetyl-aspartyl-glutamic acid and of some related compounds was carried out by negative-ion fast atom bombardment mass spectrometry and collision-induced dissociation of the generated [M-H]- species. Thorough analysis of the fragment ion spectra allowed discrimination between sequence isomeric compounds, and highlighting of differences between dipeptides linked in the normal or iso mode.

Amino Acid Sequence↗
PubMed1992

A structural study on elcatonin, a novel synthetic analogue of eel calcitonin, by fast atom bombardment and tandem mass spectrometry.

Elcatonin (ELC), a synthetic analogue of eel calcitonin, successfully used in the treatment of diseases characterized by an increase of osteoclastic activity, has been fully sequenced by combined enzymatic hydrolysis and fast atom bombardment (FAB) mass spectrometric methodology. The FAB mass spectrometric analysis on the entire molecule gave only the cluster corresponding to the molecular ion. Digestion with trypsin afforded four oligopeptides corresponding to fragments 1-11, 12-18, 19-24 and 25-32. B/E daughter ion analysis performed in turn on each protonated molecule ion in the tryptic mixture allowed complete sequencing of fragments 1-11 and 12-18, while in fragments 19-24 and 25-32 the portions 23-24 and 25-26 remained respectively unclarified. Investigation on the single oligopeptide isolated by preparative high-performance liquid chromatography and chymotryptic digestion of the molecule failed to provide any new information. One step of Edman degradation on tryptic digest permitted attribution of the 25-26 sequence to Thr-Asp. The connectivity between tryptic ELC fragments and the 23-24 sequence were proved by cleavage with V8 protease, which gave the oligopeptides 1-15 and 16-32. These were exhaustively analysed by FAB mass spectrometry.

Calcitonin↗
PubMed1989

Electron impact mass spectrometry of substituted 1,3,8-triazaspiro[4,5]decan-4-ones.

The neuroleptic butyrophenone drug spiroperidol (8-[4-fluorophenyl)-4-oxobutyl]-1-phenyl-1,3,8-triazaspiro [4,5]decan-4-one) and related compounds are valuable tools for mapping the dopamine receptors in the brain. During the development of the radiochemical synthesis of these compounds with very short-lived isotopes suitable for positron emission tomography studies, positive electron impact mass spectrometric information was obtained. Ion series are present in the spectra of all 12 compounds studied, which unambiguously allow recognition of type and site of substitution on the spiro system.

Gas Chromatography-Mass Spectrometry↗
PubMed1988

Pre-column derivatization of amino acids with N,N-diethyl-2,4-dinitro-5-fluoroaniline and reversed-phase liquid chromatographic separation.

A new method for the separation and quantification of primary and secondary amino acids by reversed-phase high-performance liquid chromatography and spectrophotometric detection is described. The use of the novel derivatizing reagent N,N-diethyl-2,4-dinitro-5-fluoroaniline yields derivatives that are more stable to light and heat in solution than the traditional ones. A simple gradient between acidic acetate buffer and acetonitrile allows the complete separation of 21 amino acids in 80 min at room temperature. The good reproducibility of peak areas and retention times allows the application of this simple and low-priced method to the determination of amino acids in the range 50-500 pmol per residue.

Amino Acids↗
PubMed1987

FD and FAB mass spectra of some oligopeptides of the tryptophyllin family.

Mass spectra of some natural thryptophyllins and synthetic analogues have been obtained by using field desorption and fast atom bombardment as soft ionization techniques to overcome the low volatility of these oligopeptides. Field desorption spectra generally show the molecular ion as base peak; some fragments of thermal origin are present at higher emitter heating current, thus providing additional structural information. Fast atom bombardment mass spectra show a more regular fragmentation of the peptide backbone, which allow the complete amino acid sequence to be checked. The presence of two consecutive proline residues in some of the examined molecules affects their fragmentation pattern in both field desorption and fast atom bombardment mass spectrometry giving rise to spectral features which are useful from the diagnostic point of view. The two ionization methods are compared and the advantage of the combined use of both techniques is pointed out.

Mass Spectrometry↗
PubMedDate not supplied

[Occupational respiratory allergopathies: environmental monitoring, air allergens, prevention].

The prevalence of allergic diseases has increased over recent years. Several epidemiological studies have been undertaken to determine the prevalence and the incidence of asthma and/or rhinitis caused by occupational allergens, and to investigate the factors that may affect their occurrence. In the last decade, with the development of methods to measure airborne allergens concentrations. Studies have been undertaken to examine the relationship between the levels of airborne allergens and the development of symptoms. In this paper we have reviewed the main studies published on the topic, and focused our attention on three aeroallergens (wheat flour proteins, latex and laboratory animal allergens), that have been thoroughly investigated in literature, from both clinical, epidemiological and laboratory aspects, which highlighted the major responsible allergens and tried to set up the dose-response relationship for symptoms and for sensitization. These studies cannot be directly compared to each other because of differences in the methods; however they seem to suggest that low levels of airborne allergens may be sufficient to sensitize individuals. In contrast, the evidence for a dose-response relationship between exposure and symptoms is indirect and not always clear. Further epidemiological studies are necessary. In occupational medicine the presence of asthma or of another allergic disease in a severe form is suggested as a criterion for excluding workers from their job. Workers that do not manifest allergic symptoms but are atopic should be informed about the risk of developing occupational respiratory diseases, and periodic check-ups are strongly recommended. Medical controls must not be disconnected from environmental controls. Standardized methods of measurement of airborne allergens for environmental control need to be set in order to allow comparison between studies and to adopt primary prevention measures.

Air Pollutants, Occupational↗
PubMedDate not supplied

Measurement of surface contamination by certain antineoplastic drugs using high-performance liquid chromatography: applications in occupational hygiene investigations in hospital environments.

Within the context of continuing interest in occupational hygiene of hospitals as workplaces, the authors report the results of a preliminary study on surface contamination by certain antineoplastic drugs (ANDs), recently performed in eight cancer departments of two large general hospitals in Milan, Italy. Since reliable quantitative information on the exposure levels to individual drugs is mandatory to establish a strong interpretative framework for correctly assessing the health risks associated with manipulation of ANDs and rationally advise intervention priorities for exposure abatement, two automated analytical methods were set up using reverse-phase high-performance liquid chromatography for the measurement of contamination by 1) methotrexate (MTX) and 2) the three most important nucleoside analogue antineoplastic drugs (5-fluorouracil 5FU, Cytarabin CYA, Gemcytabin GCA) on surfaces such as those of preparation hoods and work-benches in the pharmacies of cancer wards. The methods are characterized by short analysis time (7 min) under isocratic conditions, by the use of a mobile phase with a minimal content of organic solvent and by high sensitivity, adequate to detect surface contamination in the 5-10 micrograms/m2 range. To exemplify the performance of the analytical methods in the assessment of contamination levels from the target analyte ANDs, data are reported on the contamination levels measured on various surfaces (such as on handles, floor surfaces and window panes, even far from the preparation hood). Analyte concentrations corresponding to 0.8-1.5 micrograms of 5FU were measured on telephones, 0.85-28 micrograms/m2 of CYA were measured on tables, 1.2-1150 micrograms/m2 of GCA on furniture and floors. Spillage fractions between 1-5% of the used ANDs (daily use 5FU 7-13 g; CYA 0.1-7.1 g; GCA 0.2-5 g) were measured on the disposable polythene-backed paper cover sheet of the preparation hood.

Antimetabolites, Antineoplastic↗
PubMedDate not supplied

[Evaluation of the neurotoxic and nephrotoxic effects following long-term exposure to metallic mercury in employed at a chlorine/sodium-hydroxide plant].

OBJECTIVES: Within the frame work of a wide multicentre study, a sub-study was developed in order to explore the occurrence of early effects on the central nervous system, on the kidney and on the neuro-immune system in the workers of a chloro-alkali production plant exposed to metallic mercury at airborne concentration levels lower than 0.025 mg/m3 (TLV-TWA). They were compared to a control population of employees of the same huge petrochemical plant with different job that did not implicate exposure to mercury vapors. Specifically, the study aimed at revealing the occurrence of early effects on the central nervous system related with mercury exposure, as can be assessed through neurophysiological and neurobehavioral tests. METHODS: The excretion of urinary mercury was measured by atomic absorption spectrometry. The study of renal function was assessed by measurement of the urinary excretion of some high and low molecular weight protein markers (albumin, beta 2-microglobulin, retinol-binding protein, fibronectin, specific proximal tubule brush border antigens, N-acetyl-beta-D-glucosaminidase). The neurobehavioral status of the study subjects was assessed by means of several test parameters (Simple Reaction Time, Color Word Vigilance Test, Symbol Digit, Finger Tapping, Mood Scale of Kjellberg and Iwanowski, Subjective symptoms questionnaire (QSS), Luria Nebraska Motor Scale, Branches Alternate Movement Task and Tremometry). RESULTS: The values of urinary excretion averaged 12 +/- 8 micrograms Hg/g of creatinine for the exposed workers group (n = 38), while for the reference group (n = 34 cases) urinary excretion was statistically lower, averaging 4 +/- 6 micrograms Hg/g of creatinine. Neither the parameters selected for the assessment of renal functions, nor those chosen to probe the neurobehavioral status of the probands revealed statistically reliable differences between the group of exposed workers (length of exposure: range 1-34 years) and the control group. Nevertheless, some minor but still statistically reliable correlations were found between some neurobehavioral parameters and some demographic variables describing the whole group of tested workers, but not to the level of occupational exposure to mercury. CONCLUSIONS: The results of the study confirm the lack of toxic effects of clinical importance on the central nervous system and on the kidney for values of mercury urinary excretion lower than the suggested index of biological exposure (IBE) of 35 micrograms Hg/gram of creatinine.

Adult↗
PubMedDate not supplied

[Evolution of industrial toxicology toward vanishing doses and the human genome].

BACKGROUND: This article aims to discuss the influence that the application of the recent discoveries in genomics will have on the theory and practice of industrial toxicology in developed post-industrial countries. It is stressed that the recent advances in toxicogenomics can be integrated into the existing wealth of knowledge on the toxic properties of industrial chemicals to improve the efficacy of prevention of toxicological risk. METHODS AND RESULTS: The understanding of the biochemical and physiological mechanisms underlying susceptibility or resistance to the toxic effects of industrial xenobiotics, and in particular to carcinogens, allows us to split the epidemiologically derived relationship linking the frequency of disease in the exposed population to the level of workplace contamination into a set of sequential sub-relationships linking: a) the exposure level to that of workplace contamination; b) the internal dose to the exposure level; c) the biological effect (e.g., measured through biochemical markers of early effect) to the internal dose; d) the frequency of disease to that of observation of early biochemical effects. Each of the cited relationships is affected by a degree of uncertainty due to the variability of biological response among the examined individuals, which in turn requires a definition of the statistical limits for the association functions between the variables. As a consequence, the possibility of investigating the individual biochemical and physiological steps in the causal mechanism that links toxic exposure to disease does not necessarily lead to an increase in the information potential of biological monitoring, since the uncertainty due to inter-individual variability is amplified through the sequence of causal relationships to the point that the data from biological monitoring become valueless with regard to the prediction of the frequency or probability of disease. This is particularly true when exposure to 'low doses' is investigated, as is now increasingly frequent in post-industrial developed countries, where workplace contamination is now greatly reduced to levels which may be borderline with those in the general environment. Thus at the low-dose end of the range of contamination and exposure values there is an area where, for statistical reasons consequent to the heterogeneity of examined populations, a quantitative prediction of internal exposure due to environmental contamination, of biological adverse effects due to exposure levels and of frequency of disease due to the extent or frequency of biological effects is no longer reliably possible. This in turn impairs the preventive efficacy of biological monitoring. CONCLUSIONS: A closer integration between industrial toxicology and state-of-the-art molecular genetics derived from the recent sequencing of the human genome is the way to overcome the limitations described. In particular, the individual subjects in the examined populations can be classified with regard to some genetically controlled characters relevant to the biotransformation of xenobiotics and to DNA repair and the statistical analysis of data can be performed on more homogeneous subpopulations, in order to decrease inter-individual variability of biochemical and physiological response. This in turn increases the predictive power of the biological markers, both of dose and effect, and improves the efficacy of prevention, e.g., by highlighting oversensitive subpopulations or lifestyles which can increase the risk of occupational and environmental disease.

Carcinogens, Environmental↗