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Biomedical subjects

A Laganà

Publications and source records attributed to A Laganà.

At least 19 recordsLinked to original sources
PubMed2005

A molecular dynamics investigation of rare-gas solvated cation-benzene clusters using a new model potential.

The main static and dynamic properties of some ionic heteroclusters, involving K+, C6H6, and Ar, have been investigated. A new representation of the intermolecular potential energy, which takes into account both electrostatic and non-electrostatic contributions to the overall noncovalent interaction, was used. Dynamical calculations were performed for a microcanonical ensemble. Particular attention was paid to the opening of the isomerization and dissociation processes for K+-C6H6-Ar(n) and to the formation of some of its fragments at increasing temperatures of the cluster considered.

Benzene↗
PubMed2001

Enantiodiscrimination of chiral alpha-aminophosphonic acids by mass spectrometry.

Diastereomeric clusters between first-group metal ions (M(+)) and chiral alpha-aminophosphonic acids (A and B) have been readily generated in the gas phase by electrospray ionization (ESI) and their fragmentation investigated by mass spectrometry. The complexes studied had the general formula [MA(S)B(2)](+) and [MA(R)B(2)](+), where M = H, Li, Na, or K, A(S) and A(R) are the two enantiomers of a given acid A, and B is a reference alpha-aminophosphonic acid of defined configuration. Collision-induced decomposition (CID) of [MA(S)B(2)](+) and [MA(R)B(2)](+) leads to fragmentation patterns characterized by [MAB](+)/[MB(2)] abundance ratios which depend on the configuration of ligand A. These different spectral features were correlated to the different stability of the diastereomeric [MA(S)B(2)](+) and [MA(R)B(2)](+) complexes in the gas phase. The results have been discussed in the light of MM2 Molecular Mechanics Force Field calculations.

Journal Article↗
PubMed2000

Trace analysis of estrogenic chemicals in sewage effluent using liquid chromatography combined with tandem mass spectrometry.

A rapid, selective, sensitive, and reproducible method for the analysis of environmental estrogens, either natural or synthetic, present in samples from sewage treatment works (STW) has been developed. Isolation of these compounds from STWs was performed by applying a simple extraction procedure using an ENVI-CARB cartridge (a graphitized non porous carbon black) as the solid-phase extraction (SPE) system. Liquid chromatography coupled with atmospheric pressure chemical ionization (APCI) and tandem mass spectrometry was used for detection. For the multiple reaction monitoring (MRM) mode, the [M + H](+) ion of estrone and the [M + H-H(2)O](+) ions of 17beta-estradiol, estriol and 17alpha-ethynylestradiol were selected as the precursors for collisionally induced dissociation (CID). The average recoveries from sewage final effluent samples ranged from 84 to 93% for low levels, and from 89 to 95% for high levels. The precision of the method ranged from 11 to 8% for low level and from 9 to 7% for high level samples. The lower level of quantitation for these estrogens in STW samples was determined at 0.5 ng/L for 17beta-estradiol and 17alpha-ethynylestradiol, and 1 ng/L for estrone and estriol, based on 1-L aliquots of sewage treatment works water, using the optimum tuning parameters for each individual selected precursor ion/product ion transition. Compared to a previous gas chromatography/mass spectrometry (GC/MS) method for the analysis of ten STW samples, this method was shown to provide higher sensitivity and lower time consumption.

Calibration↗
PubMed1998

Determination of aryloxyphenoxypropionic acid herbicides in water using different solid-phase extraction procedures and liquid chromatography-diode array detection.

For isolation and trace enrichment of aryloxyphenoxypropionic acid (ArPP) herbicides from drinking, spring, and ground water a sensitive, robust method is presented. A 1-2 1 volume of aqueous samples was passed through a disposable solid-phase extraction cartridge, packed with 500 mg of Carbograph-1 at a flow-rate of 100 ml/min. After washing, ArPPs are selectively eluted with 8 ml of dichloromethane-methanol (80:20, v/v) with 50 mmol/1 formic acid and evaporated to dryness. The mixture was reconstituted with 250 microliters of water-acetonitrile (75:25; v/v) acidified with 0.1% trifluoroacetic acid and 100 microliters was injected into the high-performance liquid chromatography system. The ArPPs were separated via a binary gradient of water and a mixture of methanol-acetonitrile. Detection and confirmation were performed by diode array detection. Recovery of the six acid herbicides ranged between 90% and 98%. The limits of detection of ArPPs were 7-20 ng/l for drinking water and 16-36 ng/l for spring water. In terms of recovery and selectivity the effectiveness of Carbograph-1 cartridges was compared with that of LiChrolut-EN cartridges and polystyrene-divinylbenzene Empore disks. Relevant parameters such as pH and flow-rate for solid-phase extraction with divinylbenzene resins were optimized.

Chromatography, High Pressure Liquid↗
PubMed1998

Simultaneous determination of imidazolinone herbicides from soil and natural waters using soil column extraction and off-line solid-phase extraction followed by liquid chromatography with UV detection or liquid chromatography/electrospray mass spectroscopy.

This paper describes the simultaneous quantification of the imidazolinone herbicides (IMIs) imazapyr, m-imazamethabenz, p-imazamethabenz, m,p-imazamethabenz-methyl, imazethapyr, and imazaquin in two types of samples. (a) Groundwater, lake water, and river water samples were enriched by off-line solid-phase extraction with a Carbograph-1 cartridge and analyzed by reversed-phase liquid chromatography using a UV detector (lambda = 240 nm). The overall recoveries of IMIs extracted from 1 L of groundwater (fortified with 500-100 ng/L), 0.5 L of lake water (fortified with 500-100 ng/L), and 0.5 L of river water (fortified with 1000-200 ng/L) samples were not lower than 89%. The mean relative standard deviation (RSD) was 5.1% (ranging from 4.1% to 6.8%) in natural water. The detection limits were 30-39 ng/L in groundwater, 43-51 ng/L in lake water, and 55-67 ng/L in river water. The method involves confirmatory analysis by LC/ES-MS in full-scan mode. The dependence of the ion signal intensities on proton concentration in the mobile phase was investigated with a view to optimizing the sensitivity of the ES-MS detector. When LC/ES-MS was used, the limit of detection, calculated from extracted-ion current profiles (EICPs), was 4-7 ng/L for ground-water and 9-13 ng/L for river water. (b) Soil sample analysis utilized combined soil column extraction (SCE) and off-line solid phase extraction (SPE) for sample preparation, analyzing with LC/ES-MS under selected ion monitoring (SIM). Several different extractants were evaluated for the purpose of SCE optimization. The system that best optimizes the extractability IMIs from the soil was found to be the mixture CH3OH/(NH4)2CO3 (0.1 M, 50:50 v/v). The effect of IMI concentration in the matrix on recovery was evaluated. The total recovery of each IMI from soil at each of the two levels investigated ranged from 87% to 95%. Under three ion SIM conditions, the limit of detection (S/N = 3) was 0.1-0.05 ng/g in soil samples.

Chromatography, High Pressure Liquid↗
PubMed1995

Determination of serum total lipid and free N-acetylneuraminic acid in genitourinary malignancies by fluorimetric high performance liquid chromatography. Relevance of free N-acetylneuraminic acid as tumour marker.

The reliability of total sialic acid (TSA), lipid sialic acid (LSA) and free sialic acid (FSA) as markers in genitourinary malignancies was evaluated in 20 normal subjects, 21 patients with prostatic cancer, 22 patients with urinary bladder cancer and 14 patients with renal cell carcinoma. We introduce the new concept of 'corrected' lipid sialic acid (CLSA), which expresses the actual concentration of sialic acid bound to glycolipds by subtracting the concentration of FSA determined by a novel ultrafiltration method. TSA did not show significant differences with respect to normal controls, except for renal cell carcinoma, whose mean value (879 +/- 145 micrograms/ml) showed a P value < 0.001. Instead, CLSA showed only significant differences (P = 0.001), with respect to normal controls in stage I and in all grades of renal cell carcinoma. While all data indicated significant increases (P = 0.001) in the FSA values, (means +/- S.D.) of 0.621 +/- 0.272 micrograms/ml were found in patients with prostatic cancer, 0.796 +/- 0.443 micrograms/ml in patients with urinary bladder cancer and 0.667 +/- 0.146 micrograms/ml in patients with renal cell carcinoma. Separate TSA and CLSA measurements appeared to be of limited value in the detection of genitourinary malignancies. However, results show that FSA was the most sensitive of the three markers tested for detecting malignancies.

Adult↗
PubMed1995

Epileptic seizures in subjects previously affected by disorders of arousal.

Six patients (3M, 3F, mean age 17.3 yrs) presenting different types of evolution from disorders of arousal to epilepsy are described. All subjects during their childhood had been diagnosed in a sleep center as affected by sleep-walking (three cases) and night terrors (the other three). Successively they developed nocturnal events different from those previously exhibited and consisting of clear epileptic seizures, generalized tonic-clonic in one case and complex partial in five cases. Nocturnal monitoring allowed recognition of clear interictal paroxysmal activity in three patients, while ictal events were recorded in the remaining three. Anticonvulsant treatment (carbamazepine in five patients, phenytoin in one patient) led to the resolution of the ictal events in all cases. The fact that both disorders of arousal and epilepsy are strictly related to sleep and often share common features such as age range of onset and precipitating factors, suggests the existence of common functional substrates identifiable in constitutional maturative and biologic factors. The possible occurrence of seizures in subjects exhibiting parasomnia during their childhood has to be considered in patients with familial history of epilepsy and in all doubtful cases.

Adolescent↗
PubMed1994

Is erythropoietin-induced hypertension a phenomenon due to the intracellular Ca++ mobilisation?

UNLABELLED: The authors evaluated the ability of rHuEPO (recombinant human erythropoietin) in performing a vasoactive calcium-mediated action. Forty healthy volunteers were evaluated for the muscle blood flow at rest (RBF) and after reactive hyperemia by Xenon 133 clearance. Pre-treatments with several calcium antagonists were used. RESULTS: The i.v. infusion of rHuEPO brought about a reduction of the RBF and MBF (maximal blood flow). This reduction was maintained with nifedipine or verapamil. Gallopamil and ketanserine prevented the reduction of blood flow induced by rHuEPO. CONCLUSIONS. The rHuEPO has a vasoconstrictive action in vivo since gallopamil and ketanserine, drugs able to prevent intracellular mobilisation of the Ca++, can block the rHuEPO induced vasoconstriction. The action exerted by rHuEPO could be due not an increased flow of the Ca++ from the extracellular department but to a mobilisation from Ca++ deposits.

Adult↗
PubMed1993

A hydrolysis method using microwaves: determination of N-acetyl- and N-glycolylneuraminic acids in biological systems by fluorometric high-performance liquid chromatography.

A simple, rapid, and extremely sensitive method for determining N-acetyl- and N-glycolylneuraminic acids in serum and in submandibular, sublingual, and parotid glands using high-performance liquid chromatography with a fluorometric detector is described. The neuraminic acids contained in the samples are released in the presence of 2 M CH3COOH by means of microwave hydrolysis (only 10 min required) and are subsequently converted using 1,2-diamino-4,5-methylenedioxybenzene, a fluorogenic reagent for alpha-ketoacids, into highly fluorescent derivatives. In order to optimize the release of sialic acids and to minimize the effect of destruction, the following analytical variables were investigated: temperature, time, and concentration of the acid. Within 12 min after derivatization, the compounds were separated on a reversed-phase column by means of isocratic elution using a mobile phase of water (pH 3 with H3PO4)-methanol-acetonitrile (86:6:8, v/v). Fluorescence detection was performed at an excitation wavelength of 373 nm and an emission wavelength of 448 nm.

Animals↗
PubMed1993

Effects of intravenous administration of recombinant human erythropoietin in rats subject to hemorrhagic shock.

The effects of recombinant human erythropoietin (rHuEPO) on survival and blood pressure in hypovolemic hemorrhagic shock in rats have been studied by intravenous administration. The hormone caused an increase in the time of survival compared to the group of rats without treatment (102 +/- 4.5 vs. 25 +/- 4.5 min, p < 0.01, vehicle; 102 +/- 4.5 vs. 25 +/- 2 min, p < 0.01, saline solution) and an increase in the percentage of the surviving animals (5/7 after 120 min vs. 0/7, p < 0.05). The animals treated showed an increase in mean arterial pressure that was not present in the control group. Through their data, the authors suggest the vasopressor effect of erythropoietin. Furthermore, from other studies done before, they hypothesize that the vasoactive ability of the hormone is endothelin mediated.

Animals↗
PubMed1992

Subcutaneous bursitis in scleroderma.

We encountered 3 types of subcutaneous bursitis in our patients with scleroderma: dry bursitis characterized by a rub, sterile bursitis characterized by inflammatory effusions without crystals by polarizing microscopy, and septic (staphylococcal) subcutaneous bursitis. The latter, which occurred in 6 of 40 consecutive patients, had a protracted course, was often complicated by fistulas, and tended to involve several bursae particularly in patients with extensive calcinosis.

Adult↗
PubMed1991

General and selective isolation procedure for high-performance liquid chromatographic determination of anabolic steroids in tissues.

A multi-residue method has been developed for the determination of anabolic steroids in animal tissue. The analytes are extracted from tissue with methanol and the extract is subjected to two solid-phase extractions, one using a non-specific adsorbing material, such as graphitized carbon black (Carbopack B), and the other Amberlite CG-400 I in the OH form. This procedure allowed the neutral anabolics (testosterone, trenbolone and progesterone) to be isolated and separated from the acidic type (phenolic group), such as diethylstilbestrol, oestradiol, zeranol/zearalenone and their respective metabolites. The determination was effected using high-performance liquid chromatography with different detectors (ultraviolet, fluorimetric and electrochemical). Several analytical parameters were studied: chromatographic conditions, recoveries, evaporation step, solvent flow-rate, cartridges reusability, interference of plastic cartridges. For all the anabolics investigated the recoveries were greater than 83.6%.

Adsorption↗
PubMed1989

Simple and complex dislocations of the carpus.

The authors report 33 dislocations of the carpus; 9 simple lunate dislocations and 24 complex fracture dislocations. The number and variety of the lesions and, in particular, the variety of the types of treatment carried out allow us to draw several conclusions regarding the correct management of these rare lesions based on a long-term evaluation of the results.

Adolescent↗