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F Tagliaro

Publications and source records attributed to F Tagliaro.

At least 73 records · Page 4Linked to original sources
PubMed1990

Direct injection high-performance liquid chromatographic assay of morphine with electrochemical detection, a polymeric column and an alkaline eluent.

A simple method is described for the direct determination of morphine in untreated plasma or serum, using reversed-phase high-performance liquid chromatography with amperometric electrochemical detection. A basic eluent [0.05 mol/l phosphate buffer-isopropanol-tetrahydrofuran (88:10:2) (pH 9.5)] allows both reversed-phase chromatography of morphine under ionization control conditions and its detectability at an unprotected thin-layer glassy carbon electrode at a potential of 350 mV (vs. an Ag/AgCl reference electrode). In addition, the alkaline mobile phase promotes the ionization of serum proteins, which, being poorly retained by the hydrophobic column packing [poly(styrene-divinylbenzene) copolymer], elute early in the chromatogram, leaving a clean baseline. Up to 50 microliters of simply filtered plasma can be injected. The absolute limit of detection is 0.75 ng on-column. No interferences were observed from more than 80 opiate and non-opiate drugs. The intra- and inter-assay relative standard deviations (n = 5) were 3.2 and 6.6%, respectively, at a morphine concentration of 100 ng/ml in plasma and 0.09 and 4.2%, respectively, at the level of 500 ng/ml.

Chromatography, High Pressure Liquid↗
PubMed1990

Use of enzymatic reactors in the high performance liquid chromatographic determination of ethanol and methanol with electrochemical detection.

Despite numerous applications both in industry and in analytical chemistry, immobilized enzyme technology has encountered only limited success in modern liquid chromatography. The strict requirements of enzymatic reactors for high performance liquid chromatography (HPLC) (i.e., mechanical resistance, limited void volumes, high contact surface, high binding capacity, stable enzyme-to-matrix bond without loss of enzyme activity) are not yet fully met by commercially available products. In our laboratory, the development of post-column reactors with immobilized alcohol oxidase on-line with an HPLC/EC system has been undertaken. Three home-made reactors were produced: in the first alcohol oxidase from Candida boidinii was quasi-immobilized onto an HPLC-sized anion exchange support, in the second the enzyme was bound to a silica-based support via Schiff's base formation, and in the third a covalent linkage to an epoxy-activated hydroxyalkyl methacrylate material was chosen. Chemical immobilization proved superior to the ionic binding. The importance of limiting the post-column band spreading due to the reactor void volume, by using HPLC-size supports, was confirmed.

Chromatography, High Pressure Liquid↗
PubMed1990

Non-extraction HPLC method for simultaneous measurement of dyphylline and doxofylline in serum.

A direct injection HPLC method for the simultaneous measurement of dyphylline and doxofylline in serum is reported. Chromatography is carried out with a "Pinkerton" internal surface reversed-phase column and phosphate buffer (0.1 mol/L, pH 6.8) as mobile phase. Absorbance at 275 nm is monitored. Only 10 microL of serum is required to detect less than 1 mg of each drug per liter in biological samples. The standard curve for the method is linear over the range 6-100 mg/L, and precision is acceptable for both drugs, with CVs of 2% and 1.5% for respective concentrations of 6.2 and 25 mg/L. None of the 76 drugs tested for interference affected the measurement of either drug. Four samples can be injected per hour. This method provides a fast, accurate way to monitor two interesting therapeutic agents used in chronic obstructive airway diseases.

Chromatography, High Pressure Liquid↗
PubMed1990

[The identification of esterase D isoenzyme (EsD) phenotypes in the dental pulp by isoelectric focusing].

An identification method based on the isoelectrofocusing (IEF) assay of the EsD phenotypes in dental cavity pulp is reported. The IEF has been carried out on polyacrylamide gel (T = 5% and C = 3%), using ampholines ranging pH 4.5-5.4. A pre-focusing of 20 min at 2,000 V, 100 mA and 8 W was used; focusing conditions were: 2,000 V, unlimited current and W, for 75 min at 4 degrees C. Electropherograms were read under UV at 366 nm after reaction with 4-methylumbelliferyl acetate giving a fluorescent product. The content of a single dental cavity has been found to be the smallest amount of sample needed for the assay in alive subjects, excluding dental pathology which could interfered with the results. In bodies, excluding interferences from abnormal preservation conditions, a clear decrease in the reliability of the assay has been observed after the 6th day since the death. In any case, on the basis of the authors' experience, the dental pulp, as compared to blood, seems a preferable sample for identification purposes.

Carboxylesterase↗
PubMed1989

High-performance liquid chromatographic determination of morphine in biological samples: an overview of separation methods and detection techniques.

High-performance liquid chromatogrpahy with electrochemical detection at present suits most of the needs of toxicologists for the determination of morphine and some related compounds in biological samples, although fluorescence detection is still a useful alternative. Chemiluminescence detection may be promising, but needs further optimization of its coupling with HPLC to give the best performances. Morphine detection by absorbance spectrophotometry does not seem to allow the degree of sensitivity and selectivity from matrix interferences that is required in most instances. However, this approach is useful when morphine congeners undetectable by alternative means (i.e., heroin and morphine-3-glucuronide) are to be determined or when a general toxicological screening is required.

Chromatography, High Pressure Liquid↗
PubMed1987

Collisional spectroscopy for unequivocal and rapid determination of morphine at ppb level in the hair of heroin addicts.

A new analytical procedure for the identification of morphine in the hair of heroin addicts has been developed using collisional spectroscopy, on a commercially available, reverse geometry, double focusing instrument. Either collision-induced dissociation (B/E = const) linked scans or mass analysed ion kinetic energy spectra lead to an unequivocal and rapid determination of morphine in hydrolysed hair extract which may be compared with the data obtained by different and more traditional analytical methods.

Chromatography, High Pressure Liquid↗
PubMed1986

Parathyroid hormone, calcitonin and vitamin D metabolites in beta-thalassaemia major.

Serum calcium (Ca), phosphorus (P), alkaline phosphatase (Al-P), parathyroid hormone (PTH), calcitonin (CT), 25-hydroxyvitamin D3 (25OHD3), 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) levels and urinary excretion of Ca, P, hydroxyproline (OH-P) and cyclic AMP (cAMP) were determined in summer and in winter in 13 thalassaemic children (7 aged 3-5 years-group 1-; and 6 aged 10-13 years-group 2-), who had never taken vitamin D supplements or therapy, and in two groups of 14 controls of the same age. In thalassaemics of group 1 only serum Al-P levels and OH-P urinary excretion were higher than in controls (P less than 0.01). In thalassaemics of group 2 Ca (P less than 0.05), P (P less than 0.05), PTH (P less than 0.001), CT (P less than 0.001), 25OHD3 (P less than 0.05), 1,25(OH)2D3 (P less than 0.001) levels and cAMP urinary excretion (P less than 0.001) were lower, whereas Al-P (P less than 0.001) and CT (P less than 0.001) levels and urinary excretion of P (P less than 0.05) and of OH-P (P less than 0.001) were higher than in controls, both in summer and in winter. Advancing age induces in thalassaemic patients a decrease in PTH secretion and a consequent deficit in synthesis of 1,25(OH)2D3 that may explain some aspects of bone changes, which CT hypersecretion may tend to counteract.

Adolescent↗
PubMed1985

Liquid chromatography with pre-column dansyl derivatisation and fluorimetric detection applied to the assay of morphine in biological samples.

A simple method employing pre-column dansylation and liquid chromatography is proposed for a very sensitive and specific assay of morphine in biological samples. Nalorphine is used as an internal standard. The detection limit is 0.2 picomol of injected morphine. In the assay of human sera spiked with 150 nmol/l, the intra- and inter-assay coefficients of variation were 3.7% (n = 10) and 4.5% (n = 10), respectively. No interferences were observed from more than 70 opiate and non-opiate drugs. Urine, plasma and total blood were assayed, using different extraction methods, with negligible interference from coextractives.

Chromatography, High Pressure Liquid↗
PubMed1985

Free and bound testosterone in male heroin addicts.

The plasma levels of the active (free) fraction of testosterone (Te) and of Te Binding Globulin (TeBG) in a group of 42 heroin addicts with similar sexual difficulties were investigated for almost 2 years. Plasma levels of free Te were significantly low and TeBG were significantly high not only in the addicts with low total Te concentrations, but also in the addicts with normal values of total Te.

Adult↗
PubMed1985

A sensitive and simple assay of saliva on stamps.

Identification of saliva on stamps or envelope flaps remains yet a not widely studied problem. In most forensic laboratories it is seldom carried out, but this fact does not reduce the importance of the assay. Most authors consider amylase a sufficiently specific marker of the presence of saliva; really, the only other human body fluid that contains high amounts of this enzyme is the pancreatic juice (and therefore feces). Here we present a simple and sensitive assay for the determination of alpha-amylase that uses a commercially available and well-known substrate. It is hydrolyzed by amylase with the production of soluble blue fragments, that can be measured by photometry, obtaining objective results. The presented assay identifies 1 X 10(-6) diluted saliva or that present on 0.5 mg of a stamp; 16-year-old samples can also be identified. Intra-assay and day-to-day CV resulted in 10.8% and 13.7%, respectively. Owing to the high sensitivity of the test, handling samples or reagents can introduce contamination with saliva traces, giving false-positive results. Addition of EDTA 0.1 mol/l to the incubation mixture, lowering the sensitivity to 1 X 10(-3) diluted saliva, overcomes this problem.

Amylases↗
PubMed1985

Calcitonin serum levels in heroin addicts: effects of methadone and clonidine detoxication treatments.

Calcitonin (CT), a 32-aminoacid peptide, is secreted by the parafollicular 'C' cells of the thyroid which derive from the ultimobranchial body and, ultimately, from the neural crest. In man, the main role of this hormone is to protect the skeleton during periods of physiological stress, such as growth, pregnancy and lactation by reducing calcium loss [1]. Nevertheless, some recent data, such as the finding of immunoreactive CT-like material (iCT) in the central nervous system [2] and in the cerebrospinal fluid and the demonstration of its analgesic action in rabbits [4] and in man [5] indicate a relationship between CT and the neuroendocrine system. The purpose of the present study is to evaluate the levels of CT in a group of addicts to heroin both before and during detoxication treatment with methadone or a non-opioid drug like clonidine.

Adolescent↗
PubMed1984

High serum calcitonin levels in heroin addicts.

An involvement of calcitonin in the mechanism of pain perception has recently been hypothesized. In order to collect information about the relationship between this hormone and well known analgesic substances such as opioids, we have studied the serum levels of calcitonin in a group of heroin addicts, finding higher average concentrations than in normal subjects of matched age and sex. In these addicts there were no severe signs of impaired renal or hepatic function, or alterations of the serum levels of calcium and phosphate. So we think that opioids, in a direct or indirect way, can stimulate the secretion of calcitonin.

Adolescent↗
PubMedDate not supplied

Determination of morphine in the hair of heroin addicts by high performance liquid chromatography with fluorimetric detection.

A procedure has been presented for the quantitative determination of morphine contained in the hair of heroin addicts, by means of heat-acid hydrolysis, pre-column dansyl derivatization, straight phase liquid chromatography, and fluorescence detection. External standardization was used. Intra-assay and day-to-day variation coefficients were 5.6 and 7.8%, respectively (n = 10), when hair containing 1 ng/mg of morphine was assayed. Hair samples of 22 heroin addicts showed positive results in the range 0.08 to 15.7 ng/mg. No false positive results were found in 20 control subjects. A close correlation was shown between high performance liquid chromatography and radioimmunoassay results (y = 0.97x + 0.26)(r = 0.997, n = 15). Morphine hair content results significantly correlated with the grade of heroin use roughly estimated by means of serial determinations of morphine in urines during the last months before hair sampling.

Adolescent↗