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Biomedical subjects

P Pastore

Publications and source records attributed to P Pastore.

At least 19 recordsLinked to original sources
PubMed2005

Determination of biogenic amines in fresh and processed meat by suppressed ion chromatography-mass spectrometry using a cation-exchange column.

A new method for simultaneous determination of underivatized biogenic amines based on the separation by cation-exchange chromatography and suppressed conductivity coupled with mass spectrometry detection has been developed. The method has been applied to the analysis of cadaverine, putrescine, histamine, agmatine, phenethylamine and spermidine in processed meat products. The amines were extracted from muscle tissue with methanesulfonic acid without any additional derivative step or sample clean-up. Biogenic amines were separated by the IonPac CS17 column, a cation-exchange column used with gradient elution, and detection was done by suppressed conductivity and mass spectrometry. Tyramine was simultaneously analysed by using a spectrophotometer (275 nm) before the suppressed conductivity detection. Linearity of response was obtained in the range 0.25-25 microg mL(-1). The detection limits ranged from 23 microg L(-1) for putrescine to 155 microg L(-1) for spermidine (suppressed conductivity) and from 9 microg L(-1) for agmatine to 34 microg L(-1) for spermidine (MS). Average recoveries from meat samples ranged from 85 to 97% and coefficients of variation ranged from 4.5 to 9.7%. The analysis of biogenic amines in fresh and processed meats (dry-cured, cooked and fermented products) can be used as a quality marker of raw material and for studying the relationship between their changes and the fermentation process involved in dry sausage ripening.

Animals↗
PubMed2001

Characterization of dehydroascorbic acid solutions by liquid chromatography/mass spectrometry.

The composition of a commercial dehydroascorbic acid (DA) solution at pH 2 was investigated by liquid chromatography/mass spectrometry (LC/MS) and liquid chromatography/tandem mass spectrometry (LC/MS/MS) to establish the nature of its different forms and its decomposition products. In freshly prepared solutions, dimeric forms of DA and the hydrated bicyclic hemiketal of DA are the species mainly present in solution. In the presence of light, the initial dimeric species disappears over time to give other dehydrated dimers some of which decompose to the monomer. The comparison of these data with similar data obtained for ascorbic acid (AA) solutions under the same experimental conditions revealed that, in the presence of light, the aging of such AA solutions gives rise to only the hemiketal form of DA, and that no dimeric species of DA were formed. The presence of the hemiketal form of DA was not revealed by analysis of the same AA solutions using the conventional LC/UV technique. The natural form of DA from the oxidation of AA is the hydrated bicyclic form.

Ascorbic Acid↗
PubMed2000

A single calibration graph for the direct determination of ascorbic and dehydroascorbic acids by electrogenerated luminescence based on Ru(bpy)(3)2+ in aqueous solution

Ascorbic (H2A) and dehydroascorbic (DA) acids were for the first time directly determined in a single chromatographic run by means of the tris(2,2'-bipyridine)ruthenium(II) (Ru(bpy)(3)2+) based electrogenerated chemiluminescence (ECL) detection. For the first time, it was demonstrated that DA, a nonelectroactive compound, is ECL active and is responsible for the ECL behavior of H2A. This fact, together with the lack of a DA standard, suggested the use of a calibration graph obtained for H2A, for determining both analytes. The proven ECL activity of DA, together with literature data relative to the standard redox potentials of the different species coming from H2A, led to a reconsideration of the proposed ECL reaction mechanism for H2A. The role of the OH- ion in the reaction mechanism of the two analytes appeared to be crucial. H2A and DA could be separated by a suitable C18-reversed-phase HPLC column using an aqueous 30 mM H3PO4 solution as the mobile phase. The optimal ECL response was achieved by polarizing the working electrode at 1.150 Vvs SCE (standard calomel electrode) (oxidation diffusion limiting potential for both H2A and Ru(bpy)(3)2+). The Ru(bpy)(3)2+ solution, at pH 10 for carbonate buffer, was mixed to the eluent solution in a postcolumn system, obtaining, still at pH 10, the final 0.25 mM Ru(bpy)(3)2+ concentration. The detection limit found for the two analytes was 1 x 10(-7) M. The method was successfully applied to the determination of the analytes in a commercially available orange fruit juice.

Journal Article↗
PubMed2000

Simple and effective gas chromatographic mass spectrometric procedure for the speciation analysis of organotin compounds in specimens of marine mussels. An evaluation of the organotin pollution of the lagoon of venice.

This paper describes a simple, effective analytical procedure, based on a gas chromatographic mass spectrometric technique, for the speciation analysis of organotin compounds (OTC) in mussel samples. The direct alkylation reaction of the organotin chlorides in the aqueous digestion solution by NaBEt(4) allowed a short analysis time and a good recovery. The evaluation of the yield of each step constituting the analytical procedure indicated that the alkylation step is the most critical one. The proposed method was advantageously utilised to monitor the level of OTC pollution of the Lagoon of Venice. All the sites examined, both near to and far from anthropogenic activities, revealed significant levels of OTC pollution.

Animals↗
PubMed2000

Description and validation of an analytical method for the determination of paromomycin sulfate in medicated animal feeds.

A procedure for the extraction of paromomycin from different animal feed matrices (rabbit, chicken, pig feeds) and its subsequent determination via a reversed-phase ion-pair HPLC separation coupled with pulsed amperometric detection is described. The procedure optimised in terms of the extracting solvent and the solid phase extraction stationary phase allows the total recovery of the aminoglycoside antibiotic. The criteria used for the validation of the analytical method applied to the cited matrices are the linear dynamic range of the response, the detection limit, the repeatability, the intermediate repeatability and the accuracy. A comparison with a method described in the literature for the bulk analysis of this antibiotic is made.

Animal Feed↗
PubMed1998

Increased frequency of micronucleated kidney cells in rats exposed to halogenated anaesthetics.

Six halogenated anaesthetics were tested for their ability to induce micronuclei formation in the rat kidney. A statistically significant increase in the frequency of micronucleated cells was detected in rats given a single p.o. dose of 4 mmol/kg of halothane (3.48 x baseline), chloroform (3.32 x baseline), trichloroethylene (3.24 x baseline), sevoflurane (2.98 x baseline), and isoflurane (2.95 x baseline). In contrast, the response was substantially negative in rats given the same dose of enflurane. As compared to controls, rats treated with halothane and trichloroethylene displayed a reduction in the frequency of binucleated cells presumably due to a toxicity-induced inhibition of cellular proliferation. These findings suggest a potential genotoxic activity of halogenated anaesthetics for the rat kidney.

Anesthetics, Inhalation↗
PubMed1998

[Echo-guided radiofrequency percutaneous ablation of hepatocellular carcinoma in cirrhosis using a cooled needle].

INTRODUCTION: Radiofrequency hyperthermia using the newly-developed "cooled-tip" needle is one of the latest US-guided percutaneous treatments of hepatocellular carcinoma arising in cirrhosis. The continuous cooling of the needle tip allows tissue heating and necrosis far from the electrode without tissue charring, which was the major drawback of the old monopolar technique. Herein we report our preliminary results on feasibility and effectiveness of the thermoablation of mono- or paucifocal hepatocellular carcinoma with the cooled-tip needle. MATERIAL AND METHODS: November, 1996, to January, 1998, we treated thirteen cirrhotic patients (mean age 69.5 yrs, 10 men, 12 HCV-positive; 11 in Child's Class A and 2 in Class B) with 19 hepatocellular carcinoma nodules (mean diameter: 27 mm; range: 10-41 mm; 6 with diameter > 3 cm). None of the patients had portal thrombosis and/or extrahepatic spread. We used a radiofrequency generator (100 W power) connected to an 18 G perfusion electrode needle with an exposed tip of 2-3 cm. The circuit is closed through a dispersive electrode positioned under the patient's thighs. A peristaltic pump infuses a chilled (2-5 degrees C) saline solution to guarantee the continuous cooling of the needle tip. The needle was placed into target lesions under US guidance. The interventional procedure was carried out under general anesthesia using Propofol without intubation. Dynamic CT (more recently with the helical technique) was carried out 15-20 days after thermoablation to assess treatment efficacy. RESULTS: In all, 31 thermal injuries (at 1000-1200 mA for 10-15 minutes) were caused in 21 sessions in the 19 hepatocellular carcinoma nodules (mean: 1.5 lesions per nodule and 1.6 sessions per patient). Complete necrosis as assessed at dynamic CT (no enhancement during the arteriographic phase) was achieved in 16 of 19 nodules (84%). No side-effects occurred. During the follow-up (median: 11 months) no death occurred and five patients had recurrent hepatocellular carcinoma appearing either as single nodule or as multinodular liver involvement. CONCLUSIONS: In our experience radiofrequency hyperthermia with the cooled-tip needle permits effective and safe percutaneous ablation of HCC in cirrhosis. In addition, treatment time is short and lesions > 3 cm can be treated. Further experience is needed to better define the role of percutaneous thermoablation in the treatment strategy of hepatocellular carcinoma.

Aged↗
PubMed1997

Relapsing neoplastic seeding after percutaneous ethanol injection for hepatocellular carcinoma. Clinical and ultrasonographic findings in a cirrhotic patient.

A case of neoplastic implant after percutaneous ethanol injection (PEI) therapy for hepatocellular carcinoma (HCC) occurring in two steps is described. A 74-year-old male cirrhotic patient underwent PEI for a 5-cm HCC nodule. To obtain complete tumoral necrosis, 80 ml were injected under sonographic guidance in four sessions. Ten months after the completion of PEI a subcutaneous nodule was palpated in the abdominal wall within the area of needle punctures. Histologic examination of the excised nodule confirmed the sonographic and Power Doppler diagnosis of metastatic HCC. At the US exam scheduled three months later a non-palpable subcutaneous nodule of 16 mm was appreciated near the surgical wound. Once again metastatic HCC was demonstrated at pathological examination. Copyright 1997 Elsevier Science Ireland Ltd.

Journal Article↗
PubMed1997

An in vivo micronucleus assay for detecting the clastogenic effect in rat kidney cells.

A micronucleus assay in vivo has been developed that is based on the use of freshly isolated kidney cells from mononephrectomized rats. In this validation study, a statistically significant increase in the frequency of micronucleated cells was detected in rats given i.p. a single dose of four kidney carcinogens, N-nitrosodimethylamine, N-nitrosodiethylamine, N-ethyl-N-hydroxyethylnitrosamine and N-nitroso-N-methylurea. The clastogenic effect was more marked when the same dose was injected for 3 successive days. As compared to controls, treated rats displayed a reduction in the frequency of binucleated cells, presumably due to a toxicity-induced inhibition of cellular proliferation. The proposed method should be suitable for the detection of the clastogenic effect of procarcinogens biotransformed into reactive species in the kidney.

Animals↗
PubMed1994

Efflux of dopamine from the synaptic cleft in the nucleus accumbens of the rat brain.

Synaptic release of dopamine in the nucleus accumbens of the intact rat brain elicited by a single electrical impulse applied to ascending dopaminergic fibers results in extracellular concentrations sufficient to bind the known dopamine receptors. The dopamine concentration observed after four rapid, sequential pulses is exactly four times greater and is unaffected by pharmacological antagonism of dopamine uptake and receptor sites at supramaximal concentrations. Thus, dopamine efflux from the synaptic cleft is not restricted by binding to intrasynaptic proteins on the time scale of the measurements (50-100 msec). The extracellular concentration, as a result of a single stimulus pulse, is 0.25 microM and is rapidly removed by extrasynaptic uptake. This maximal, transient concentration of dopamine is 60 times higher than steady-state concentrations reported previously using dialysis techniques, illustrating that dopamine extracellular concentrations are spatially and temporally heterogenous. In contrast to ACh transmission at the neuromuscular junction, the dopamine synapse in the telencephalon is designed for the effective efflux of dopamine from the synaptic cleft to the extrasynaptic compartment during neurotransmission.

Animals↗
PubMed1988

Surgical management of ileosigmoid fistulas in Crohn's disease.

Radiologic and endoscopic demonstration of ileosigmoid fistulas is difficult: some are discovered only at operation. In these cases the surgeon is faced with the decision of either to remove "en bloc " the involved bowel or to simply close the sigmoid defect. Twelve patients with Crohn's disease complicated by ileosigmoid fistulas were operated: 7 by ileal and/or colonic resection and simple closure of the sigmoid fistula, 4 by double resection and 1 by total colectomy. Stomas were performed in 2. The review of this experience demonstrated that conservative surgery is effective and safe in most cases. Local extended resection should be reserved to cases where secondary involvement of a rather long segment of the intestine is present or where the sigmoid and rectum are primarily involved by active severe Crohn's disease. In these cases, a protective stoma may be considered.

Adolescent↗
PubMed1984

Arginine thiazolidinecarboxylate in the treatment of chronic active hepatitis: double-blind comparison with placebo.

Forty-four patients with chronic active hepatitis were given arginine thiazolidinecarboxylate (800 mg/day per os for 40 days) or placebo in a randomized, double-blind trial. The most important liver function parameters were measured in each patient at the beginning of the trial, after 20 days, and at the end of the trial. The active drug lessened the parameters of necrosis and cholestasis while protein synthesis improved in liver cells. The differences between ATCA and placebo groups were highly significant. No treatment-related side-effects were reported.

Adolescent↗
PubMed1984

Twenty-five years' experience treating cerebro-rhino-orbital mucormycosis.

Mucormycosis is an acute fungal disease with high mortality exhibiting craniofacial, pulmonary, cutaneous, gastrointestinal and disseminated forms. Cerebro-rhino-orbital (CRO) mucormycosis is the type that most frequently involves the structures of the head and neck. While usually non-pathogenic, these saprophytic organisms can be particularly lethal in chronically debilitated patients. Between the years 1957 and 1982, 18 cases of CRO mucormycosis were seen at the Medical College of Virginia Hospital and the McGuire VA Medical Center. Four illustrative cases of CRO mucormycosis are presented to emphasize: the importance of clinical awareness of the disease, the necessity of tissue biopsy for diagnosis, the need of appropriate management of any underlying disorder, administration of amphotericin-B, and the performance of adequate surgery.

Adult↗
PubMedDate not supplied

Substernal goiters.

BACKGROUND: Substernal goiter, also said cervico-mediastinic goiter, is a thyroid formation with cervical departure that goes beyond, with stretched neck, the superior thoracic strait for at least 3 cm and that preserves, generally, the parenchimal or fibrous connections between the cervical and thoracic portion, maintaining a direct vascularization supplied by the thyroid arteries. The prevalence of this pathology is very variable and fluctuates between 1.7% and 30% of all thyroid damages. The actual classification is provided by the radiologic examination of the chest and, above all, by the new techniques of imaging. METHODS: In the period between January 1998 and December 2003, 332 patients with thyroid pathology have been treated surgically. Forthy-five (13.5%) of these were afflicted with a cervico-mediastinic goiter. In 32/45 (71.1%) cases a total thyroidectomy has been performed by collar carving in accordance with Kocher; in 11/45 (24.5%) cases an hemithyroidectomy has been performed by collar incision; in 2/45 (4.4%) cases, already submitted to surgical intervention of isthmus-lobectomy a totalization has been performed. RESULTS: The surgical technique foresees always an anterior collar neck incision. This way of access is to prefer in the substernal goiters, both for the presence of a cervical vascularization easy to control and for the possibility, nearly always realizable, to dislocate the goiter by that way. As for what concerns the results of the histological examination, in 2/45 (4.5%) cases it has been set a diagnosis of follicular carcinoma (one of them surely invading and the other, leastly invading), in 3/45 (6.6%) cases papillary carcinoma, in 4/45 (8.8%) cases colloido-cystic goiter, in 33/45 (73.5%) cases micro-macrofollicular hyperplasia (in one of which contemporarily compromise from lymphoma of Hodgkin); in 3/45 (6.6%) cases of adenomatous hyperplasia of the thyroid. DISCUSSION: The surgical approach has been in all cases the collar neck incision in accordance to Kocher, and it has never been necessary to associate a sternotomy or thoracotomy. After the intervention, in all the patients the symptomatology tied to the mediastinal compression has disappeared. The goiter showed signs of neoplastic degeneration in 11.1% of the cases, with prevalence of the papillary carcinoma in the 6.6% and, in the remaining 4.5%, of follicular carcinoma. These data are superimposable to the data gathered in other surveys. All the patients passed the post-operating hospitalization in optimal conditions and have been discharged during the fourth post-operating day with the prescription of increasing levothyroxine doses according to the body weigh.

Adenocarcinoma, Follicular↗