[Comparison of 2 different invitation methods for mammography screening].
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Female↗
Biomedical subjects
C Lucarelli
Publications and source records attributed to C Lucarelli.
Analytical strategy for the assessment of the protein glycation status in uremic patients by high-performance liquid chromatography.
We propose a newly integrated procedure for the analysis of furosine (early glycation product) and pentosidine (glycoxidation end-product) in plasma proteins and the simultaneous assessment of advanced glycation end-product (AGE) peptides and free pentosidine in plasma. In order to determine furosine and protein-linked pentosidine, plasma proteins were hydrolyzed in 8 M HCl and each analyte was purified by solid-phase extraction. Furosine was determined by ion-pair RP-HPLC methodology with isocratic elution and spectrophotometric detection at 280 nm and pentosidine by ion-pair RP-HPLC by using gradient elution and fluorimetric detection at 335/385 nm. To assess free pentosidine concentration and simultaneously evaluate the AGE peptides, an aliquot of plasma sample was diluted and ultrafiltered by using Centricon 10 M(r) < or = 10,000) ultrafiltration membranes. Free pentosidine and AGE peptides were analysed by ion-pair RP-HPLC, by using gradient elution and fluorimetric detection at 385 nm upon excitation at 335 nm. The HPLC methodology has been successfully used for the determination of glycation and glycoxidation protein status in uremic patients.
Arginine↗
High-performance liquid chromatographic determination of total plasma homocysteine with or without internal standards.
Hyperhomocysteinemia is an independent risk factor for atherosclerosis and vascular occlusive disease. Assessment of total plasma concentration of homocysteine (tHcys) requires accurate and reproducible measurements. The aim of this study was to test a rapid isocratic HPLC method for tHcys analysis with an internal standard (I.S.) of alpha-mercaptopropionylglycine (MPG), 2-mercaptoethylamine (ME), or N-acetylcysteine (NAC) or without I.S., and to verify whether the use of an I.S. improves the precision. The method without I.S. showed an excellent linearity (y = 1.59x - 0.15, r = 1), recovery (100%) and a within-assay relative standard deviation (R.S.D.) of 1.2%. Instead, in our hands, the presence of I.S.s decreased the reproducibility (within-assay R.S.D. ranged from 4.5 to 6.5%) and lengthened the chromatogram by up to four to five times. In conclusion, HPLC measurement of plasma tHcys without I.S. improves accuracy with respect to determination with I.S.; moreover, this approach allows to routinely process larger amounts of plasma samples.
Chromatography, High Pressure Liquid↗
Possible functional modulation by acetylcholine of nitric oxide on guinea pig isolated trachea.
The aim of this study was to evaluate whether acetylcholine induces NO release. We determined the responses on the cholinergic component of the response to electrical field stimulation (EFS) the effects of L-nitro-arginine-methyl-ester (L-NAME; 1 mM), an inhibitor of NO synthase, of L-Arginine (L-ARG; 1 mM), a precursor of NO synthesis, and methoctramine (0.01-0.1-1 microM), an antagonist of M2 receptors, alone or associated with L-NAME. The experiments were performed on guinea pig isolated intact- or denuded-epithelium tracheal rings contracted in a frequency-dependent manner to EFS. At the maximum frequency tested (30 Hz), the contractile response elicited was 60.36 +/- 0.61% of acetylcholine (100 microM) contraction, while the maximal relaxant effect induced by EFS was -28.40 +/- 0.61% in epithelium intact preparations. A pretreatment with L-NAME significantly (P<0.05) increased the contraction (76.08 +/- 1.39%) and reduced the relaxation elicited by EFS. L-NAME effect on both EFS induced responses were statistically (P<0.05) reversed by the association L-NAME + L-ARG. Methoctramine (1 microM) enhanced contractile (P<0.05) (79.20 +/- 2.21%), as well as relaxant responses (-38.73 +/- 0.99%) elicited by EFS in guinea pig epithelium-intact tracheal rings; in a separate series of experiments, performed on guinea pig epithelium-intact rings, L-NAME increased the contractile responses to methoctramine (82.6 +/- 2.31), but reduced the relaxant ones (26.38 +/- 1.29). In contrast, at the maximum frequency tested, it increased only the contractile response, but not modify the relaxant one, in epithelium denuded rings. In conclusion, the present data showed that the release of acetylcholine from postganglionic cholinergic nerves plays an important role on NO formation and this effect may be modulate by epithelium.
Acetylcholine↗
Vascular effects of acute hyperglycemia in humans are reversed by L-arginine. Evidence for reduced availability of nitric oxide during hyperglycemia.
BACKGROUND: Acute hyperglycemia may increase vascular tone in normal humans via a glutathione-sensitive, presumably free radical-mediated pathway. The objective of this study was to investigate whether or not the vascular effects of hyperglycemia are related to reduced availability of nitric oxide. METHODS AND RESULTS: Acute hyperglycemia (15 mmol/L, 270 mg/dL) was induced in 12 healthy subjects with an artificial pancreas. Systolic and diastolic blood pressures, heart rate, and plasma catecholamines showed significant increases (P < .05) starting after 30 minutes of hyperglycemia; leg blood flow decreased significantly (15%; P < .05) at 60 and 90 minutes. Platelet aggregation to ADP and blood viscosity also showed significant increments (P < .05). The infusion of L-arginine (n = 7, 1 g/min) but not D-arginine (n = 5, 1 g/min) or L-lysine (n = 5, 1 g/min) in the last 30 minutes of the hyperglycemic clamp completely reversed all hemodynamic and rheological changes brought about by hyperglycemia. Infusion of NG-monomethyl-L-arginine (L-NMMA; 2 mg/min) to inhibit endogenous nitric oxide synthesis in 8 normal subjects produced vascular effects qualitatively similar to those of hyperglycemia but quantitatively higher (P < .05); however, heart rate and plasma catecholamine levels decreased during L-NMMA infusion, presumably as a consequence of baroreflex activation. Infusion of L-NMMA during hyperglycemia produced changes not different from those obtained during infusion of L-NMMA alone. CONCLUSIONS: The results show that acute hyperglycemia in normal subjects causes significant hemodynamic and rheological changes that are reversed by L-arginine. Moreover, the effects of hyperglycemia are mimicked to a large extent, but not entirely, by infusion of L-NMMA. This suggests that hyperglycemia may reduce nitric oxide availability in humans.
Acute Disease↗
Factors affecting lipoprotein lipase in hypertensive patients.
Arterial hypertension is frequently associated with serum lipid abnormalities. Lipid metabolism can also be affected by antihypertensive treatment, possibly via an interference with lipoprotein lipase (LPL) activity. The aims of this study were to investigate the metabolic and hemodynamic factors that can interfere with plasma postheparin LPL activity in a sample of 13 patients with mild, uncomplicated arterial hypertension. The effects of vasodilator administration (prazosin and hydralazine) alone or in combination with a beta-blocker (propranolol) were also studied. A direct correlation between serum insulin levels and LPL activity was found during placebo treatment. This was confirmed by multiple regression analysis, which also showed a positive correlation of LPL activity with aortic flow velocity and plasma adrenaline (F significance = 0.0007, R2 = .905). Serum insulin was also directly correlated with cholesterol in high-density lipoproteins (HDLs) and in the HDL2 subfraction. A significant decrease in LPL activity was observed during the addition of propranolol to vasodilators as compared with vasodilators alone. A positive correlation was found between LPL and adrenaline changes induced by the combined treatment. These data suggest that LPL may play a role in the pathophysiologic connections between insulin action, the adrenergic nervous system (ANS), and lipid metabolism.
Blood Pressure↗
Glutathione reverses systemic hemodynamic changes induced by acute hyperglycemia in healthy subjects.
The present study aimed at evaluating whether acute elevations of plasma glucose concentrations could influence systemic hemodynamic parameters and baroreflex activity in humans. Plasma glucose concentrations were acutely raised to 15 mmol/l in 12 healthy male volunteers. During hyperglycemia, there were significant increments of systolic [from 118 +/- 9 to 138 +/- 12 (SD) mmHg, P < 0.01] and diastolic (from 71 +/- 5 to 85 +/- 6 mmHg, P < 0.001) blood pressure, as well as heart rate (from 76 +/- 7 to 85 +/- 10 beats/min, P < 0.01) and plasma catecholamine levels. Both maximal and steady-state mean arterial pressure after squatting were higher during hyperglycemia (27 +/- 8 and 16 +/- 6 mmHg, respectively) compared with levels obtained during euglycemia (18 +/- 5 and 2 +/- 0.6 mmHg, respectively, P < 0.001). The infusion of the somatostatin analogue octreotide (25 micrograms as i.v. bolus followed by a 0.5 microgram/min infusion), to avoid the possible confounding vascular actions of insulin, did not influence the hemodynamic effects of hyperglycemia except for a lesser increase of both heart rate and plasma catecholamines. Glutathione (600 mg as an iv bolus followed by a 5 mg/min infusion) completely prevented the vascular effects of hyperglycemia. This study shows that acute hyperglycemia, similar to that observed in poorly controlled diabetic patients, produces relevant systemic hemodynamic changes and also alters baroreflex activity via a glutathione-sensitive presumably free radical-mediated pathway.
Adult↗
Effects of RO 5-4864 and PK 11195 on guinea pig trachea.
Previous reports have suggested a role played by peripheral benzodiazepine receptors (PBZ) in the regulation of calcium. The aid of this investigation was to evaluate the effects of Ro 5-4864 (PBZ agonist) and PK11195 (PBZ antagonist) in guinea pig trachea and their possible role in the regulation of calcium. Ro 5-4864 and PK 11195 showed spasmolytic effects on the contraction curve induced by acetylcholine. Moreover, Ro 5-4864, PK 11195 and diltiazem (a Ca2+ -antagonistic drug) shifted to the right the contraction curves induced by acetylcholine, potassium chloride (KCl), calcium chloride (CaCl2), or by Bay K 8644. These results demonstrate that the benzodiazepines and their antagonists may exhibit Ca2+ -antagonistic activity. Ro 5-4864 and PK 11195 may exert this effect at a site that is a component of, or is associated with, voltage operated calcium channels (VOC).
Acetylcholine↗
Ondansetron, an antagonist of 5-HT3 receptors, in the treatment of antineoplastic drug-induced nausea and vomiting in children.
The aim of this study was to evaluate the efficacy and safety of ondansetron, an antagonist of 5-hydroxytryptamine type 3 (serotonin 3) (5-HT3) receptors, in controlling nausea and vomiting induced by antineoplastic therapy in children affected by cancer. Six patients affected by nausea and vomiting due to antineoplastic drugs were treated with ondansetron (4 mg/m2). Urinary samples for the assay of serotonin and 5-hydroxy-indoleacetic acid (5-HIAA) were collected 24 hr before antineoplastic drug treatment, 24 hours after the start of antineoplastic therapy and, 24 hr after the start of ondansetron therapy. All patients were affected by nausea and vomiting within two to four hr after the antineoplastic treatment. Urinary concentrations of serotonin and 5-HIAA were higher and statistically significant (P < 0.01) with respect to basal values. Treatment with ondansetron significantly reduced the number of episodes of nausea and vomiting, as well as the urinary values for serotonin and 5-HIAA.
Antineoplastic Combined Chemotherapy Protocols↗
Evaluation of 2-(2-thiophenecarboxy)benzoic acid and related active metabolites in biological samples.
This paper describes a quantitative assay of 2-(2-thiophenecarboxy)benzoic acid and its systemic metabolites, namely salicylic acid and thiophenecarboxylic acid, by high-performance liquid chromatography with ultraviolet detection at 254 nm. Analytes were extracted from acidified samples with tert.-butylmethyl ether and separated with an RP-18 column (150 mm x 3 mm I.D., 5 microns particle size) with a mixture of 0.01 M potassium phosphate and methanol (70:30, v/v) at pH 3.1. The method proved to have the validation required for pharmacokinetic investigations in animals and humans.
Animals↗
Free plasma catecholamine levels in healthy subjects: a basal and dynamic study. The influence of age.
We studied the levels of free plasma noradrenaline (norepinephrine, NE), adrenaline (epinephrine, E), and dopamine (DA) in 143 normal subjects, either basally or, in a part of them, in response to four tests stimulating the sympathoadrenomedullary activity: the tilt-table test (TTT), the cold-pressor test (CPT), the mental-arithmetic test (MAT), and the insulin tolerance test (ITT). In both cases we evaluated the influence of age, which is considered the main physiological variable affecting the peripheral sympathetic activity. A normal distribution of values was observed, in the basal study, only for NE, while E and particularly, DA levels were distributed in an non-homogeneous fashion; a direct correlation was observed between age of subjects and NE levels, while neither E, nor DA levels showed any correlation with the aging process; sex did not influence any of the catecholamines. In the dynamic study, CPT, ITT and, above all, TTT elicited a significant rise in NE levels, while the E release was greatly stimulated by the insulin-induced hypoglycaemia. Neither NE, nor E levels rose after the MAT stimulation. Also in this case, the elderly showed an increased noradrenergic responsiveness when compared with the young subjects, confirming the existence of an 'up-regulation' of the peripheral sympathetic tone in old people.
Adolescent↗
Clinical pharmacokinetics of teicoplanin and aminophylline during cotreatment with both medicaments.
The influence of teicoplanin and aminophylline (theophylline ethylenediamine) on their mutual steady-state pharmacokinetics was studied in two parts, namely experimental and clinical studies. The concentrations of teicoplanin and aminophylline (theophylline) were evaluated at several times after intravenous administration of teicoplanin (3 and 15 mg/kg) and aminophylline (5 mg/kg) in 12 rabbits. Ten COPD patients were treated for 5 consecutive days with a short-term intravenous infusion of 240 mg aminophylline twice daily; ten more patients received for 5 days a short-term intravenous infusion of 200 mg teicoplanin twice daily. On the last day, blood samples were taken for teicoplanin and theophylline determination by means of the HPLC method. Subsequently, while aminophylline and teicoplanin were continued at the same dosage, the first ten patients received in addition a short-term intravenous infusion of 200 mg teicoplanin twice daily, and the second ten patients a short-term intravenous infusion of 240 mg aminophylline twice daily. After 5 days the serial assays of serum teicoplanin and theophylline were repeated. Our results demonstrated, in both experimental and clinical studies, no influence of theophylline on the steady-state pharmacokinetics of teicoplanin. Likewise teicoplanin had no significant effect on the steady-state pharmacokinetics of intravenous administration of theophylline in the form of aminophylline.
Aged↗
Serum steroid hormonal profiles by reversed-phase liquid chromatography in patients with 17-hydroxylase deficiency and in an affected family.
We used an optimized isocratic reversed-phase high-performance liquid-chromatographic procedure to separate and measure 12 steroid hormones, and studied the steroid hormone profiles in sera from three patients with 17-hydroxylase deficiency (17-OHD). Two of the patients were sisters, one of whom (II-3), expressing normotension and primary amenorrhea, was diagnosed on the basis of chromatographic data and followed up for seven years. The untreated patients had obvious abnormalities on chromatograms of serum extracts, characterized by markedly increased corticosterone (B) and decreased or undetectable cortisol (F) and cortisone (E). The concentration of 11-deoxycorticosterone was much greater in the patient with classical symptoms than in the normotensive patient. In all three patients, concentrations of aldosterone were within the normal range, but concentrations of progesterone were much lower than in the patients with 21-hydroxylase deficiency. We evaluated the responses to corticotropin and dexamethasone. HPLC evaluation of the serum steroid profiles before and after corticotropin stimulation in the affected family showed that in the parents and one other sibling, concentrations of F before and after stimulation were within the normal ranges. The sums of the ratio of B to F before and the ratio of B to F after corticotropin stimulation (sigma B/F) in the parents and the other sibling were 0.292, 0.496, and 0.614, respectively, all much higher than the normal value (mean +/- SD: 0.164 +/- 0.038). Thus the sigma B/F value may be a hormonal marker of heterozygotes carrying this defect.
Adolescent↗
Determination of 2'-deoxy-5-iodouridine and its metabolite 5-iodouracil by high-performance liquid chromatography with ultraviolet absorbance detection in human serum.
A new assay is described for 2'-deoxy-5-iodouridine, a drug employed as an antiviral agent by topical application. The parent drug, its systemic metabolite 5-iodouracil and an internal standard (5-iodouridine) were extracted from salted serum by an ethyl acetate partition at pH 6.7, back-extracted in alkalinized water and injected into a reversed-phase column. Potassium phosphate buffer-acetonitrile (95:5, v/v) eluted the analytes at a flow-rate of 1.5 ml/min. Detection was at 290 nm. The method proved to be linear in the 100-2000 ng/ml range.
Antiviral Agents↗
Micro-liquid chromatography method for the determination of ciclopiroxolamine after pre-column derivatization in topical formulations.
Ciclopiroxolamine is a broad-spectrum antimycotic drug. Neither the free acid (ciclopirox) nor its salt with ethanolamine (ciclopiroxolamine) can directly be quantified by liquid chromatography (LC) on both normal and reversed phases. This is due to the chelating function of the N-hydroxypyridone group that interacts strongly with stationary phases. Derivatization by alkylation forms a 1-alkyloxypirydone with regular chromatographic behaviour. A micro-LC method based on an isocratic elution reversed-phase system for quantification of ciclopiroxolamine in topical formulations is described. Chromatography was carried out using an LC Packings fused-silica capillary column (15 cm x 330 microns I.D.; Delta Pak, RP-18, 5 microns, 300 A) coupled to a Kontron 433 UV capillary detector. Data with respect to the derivatization reaction, recovery, reproducibility and limits of detection of the proposed method are reported and discussed.
Administration, Topical↗
High-performance liquid chromatographic determination of acetone in blood and urine in the clinical diagnostic laboratory.
A method for the determination of acetone in plasma or urine by high-performance liquid chromatography (HPLC) was developed. Plasma specimens are deproteinized with acetonitrile (1:1, v/v) 2,4-dinitrophenylhydrazine (DNPH) is added to the supernatant or to filtered urine samples, similarly treated with acetonitrile (2:1, v/v) to prevent crystallization of the synthesized phenylhydrazone. An aliquot (20 microliters) of the reaction mixture was subjected to HPLC at ambient temperature using a reversed-phase Pecosphere 3 x 3 C18 column with acetonitrile-water (45:55, v/v) as eluent at a flow-rate of 1 ml/min and detection at 365 nm. Hydroxyacetone and acetoacetate phenylhydrazone derivatives do not interfere. The identification of acetone by its retention time was confirmed by comparison with a laboratory-synthesized acetone DNPH derivative. The concentration of acetone, eluted within 3 min, was determined by the peak-height method. The detection limit was 0.034 mmol/l; the relative standard deviations were less than 5% within run (n = 20) and less than 10% between run (n = 20).
Acetone↗
Measurement of the ovarian cancer-associated antigen CA 125 in monitoring tumor burden and response to chemotherapy.
CA 125 serum levels were measured in 74 patients with ovarian carcinoma. Among 31 patients undergoing a second look laparotomy (SL) after chemotherapy pathologic complete response (PCR) was observed in 14 patients, residual disease (RD) less than 2 cm in 7 patients and RD greater than 2 cm in 10 patients. The disease status was compared to the CA 125 serum levels measured just before SL. Thirteen of the 14 patients with PCR had serum CA 125 values less than 35 U/ml (specificity: 93%). On the other hand, only 10 of the 17 patients with RD showed serum levels greater than 35 U/ml (sensitivity: 59%). Moreover, in the 43 patients receiving chemotherapy, CA 125 levels correlated with the course of the disease in 36 (84%). With regard to early detection of recurrence, in 9/14 patients with PCR, whose CA 125 levels were monitored monthly, by 1 to 7 months an increase of the tumor marker preceded clinical evidence of relapse in 9/9 relapses (100%). In conclusion, CA 125 assay can be helpful in the management of ovarian cancer patients, in monitoring the response to chemotherapy, in the early detection of tumor recurrence, and in predicting the SL findings, although the low sensitivity could be a major drawback in patients with RD before SL.
Adult↗
Improvements in automated analysis of catecholamine and related metabolites in biological samples by column-switching high-performance liquid chromatography.
Previously two fully automated methods based on column switching and high-performance liquid chromatography have been described, one for plasma and urinary catecholamines and the other for catecholamine urinary metabolites. Improvements in these methods, after 3 years of routine application, are now reported. The sample processing scheme was changed in order to eliminate memory effects and, in the procedure for plasma catecholamines, a pre-analytical deproteinization step was added which enhances the analytical column lifetime. The applied voltages for the electrochemical detector have been optimized, resulting in an automated method, suitable for the simultaneous determination of vanillylmandelic acid, 3,4-dihydroxyphenylacetic acid, homovanillic acid and 5-hydroxyindoleacetic acid. The sensitivity of the methods allows the detection of 2-3 ng/l of plasma catecholamines and 0.01-0.06 mg/l of urinary metabolites. Also, it is possible to switch from one method to the other in only 30 min. The normal values obtained from 200 healthy people are reported, together with a list of 57 potential interfering substances tested.
Catecholamines↗