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Biomedical subjects

E De Vecchi

Publications and source records attributed to E De Vecchi.

18 recordsLinked to original sources
PubMed2000

Serum and lung levels of thiamphenicol after administration of its glycinate N-acetylcysteinate ester in experimentally infected guinea pigs.

Thiamphenicol is an analogue of chloramphenicol and is characterised by a broad spectrum of action. In this study, serum and lung levels of thiamphenicol (TAP) were studied in infected guinea pigs after the administration of thiamphenicol glycinate N-acetylcysteinate (TGA). Animals received a single dose of TGA (15 mg/kg, subcutaneously) immediately after intra-tracheal infection with Haemophilus influenzae (about 10(7) CFU/animal). Serum and lung concentrations of TAP were determined at 0, 1, 3, 6, 12 and 24 h after drug administration by means of HPLC. TAP serum levels were elevated at 1 h and remained detectable for 24 h after drug administration. Tissue lung levels were comparable to peak serum concentrations but remained higher and decreased more slowly than serum concentrations.

Acetylcysteine↗
PubMed1999

Effects of three different fish oil formulations on Helicobacter pylori growth and viability: in vitro study.

Helicobacter pylori infection is currently treated with antimicrobial agents in combination with antacids. Recent studies have described the in vitro bactericidal activity of fish oils and polyunsaturated fatty acids on H. pylori, and reduced rates of duodenal ulcer in people with high intake of these substances. In this study we have tested the in vitro activity of three different fish oil formulations on H. pylori strains using the Kirby Bauer method and an in vitro antibacterial test on bacteria adhered to cellular monolayers. Our results demonstrate that one of the oils is active. In this study we cannot speculate on which component of the active oil is effective and its mechanism of action, but we hypothesize that a higher concentration of icosapentaenoic acid and docosahexaenoic acid occurs in the active oil. Further in vitro and in vivo studies are needed before proposing fish oils as treatment of H. pylori infection.

Agar↗
PubMed1998

Protection from renal ischemia-reperfusion injury by the 2-methylaminochroman U83836E.

BACKGROUND: In a prior study the 21-aminosteroid (lazaroid) U74389F provided in vivo protection from oxidative stress when used as a preventive therapy in ischemia-reperfusion injury in the kidney. As the cell membrane is the principal site for lipoperoxidation, in the current study the very lipophilic 2-methylaminochroman U83836E, a recently developed lazaroid, was administered to rats at 3 mg/kg before renal ischemia-reperfusion. In addition to the biochemical parameters, the renal function and the histological appearance were carefully evaluated. METHODS: Glutathione, adenine nucleotides and lipid peroxidation products were determined in kidneys reperfused for 2 and 24 hours after 90 minutes of ischemia. Renal function was assessed by plasma creatinine, and renal injury by histological examination. RESULTS: Reperfusion-induced glutathione oxidation, expressed as an oxidized-to-total glutathione ratio, was significantly attenuated both after 2 and 24 hours of reperfusion by treatment with U83836E. Adenosine triphosphate (ATP) was still significantly depleted after 24 hours in the control group, while at the same time treated animals had already recovered to baseline values. Lipid peroxidation products were significantly lower in lazaroid-groups both after 2 and 24 hours of reperfusion. Renal function after 24 hours of reperfusion was notably better in the treated rats. Histological examination confirmed the protective action of the drug. After 24 hours the control group showed large areas of parenchymal hemorrhage and necrosis with dilated tubules and blood vessel thrombosis, while treated animals showed small necrotic areas with a background of mild interstitial inflammatory cells. CONCLUSIONS: Our results suggest that there is a protective effect of U83836E in ischemia-reperfusion injury, in that tissue damage due to oxidative stress is reduced, thus ameliorating renal function impairment.

Animals↗
PubMed1998

Relation between left ventricular function and oxidative stress in patients undergoing bypass surgery.

OBJECTIVE: To determine whether preoperative left ventricular ejection fraction (LVEF) is related to the degree of myocardial oxidative stress during bypass surgery in man. DESIGN: Observational study. SETTING: Tertiary care centre. PATIENTS AND INTERVENTIONS: 31 patients (LVEF range was 20% to 68%) undergoing elective coronary bypass surgery with blood cardioplegic reperfusion were studied. Arterial and coronary sinus blood was collected before aortic cross clamping (T0) and at 0 (T1), 15 (T2), and 30 (T3) minutes after unclamping. Transmural left ventricular biopsies were also obtained from 15 patients at T0 and at T1. MAIN OUTCOME MEASURES: Glutathione and adenine nucleotides were measured in myocardial biopsies, while coronary sinus-artery differences for glutathione, nucleotides, and products of lipid peroxidation were calculated from blood specimens. Creatine kinase (myocardial band; CK-MB) was measured in plasma at four and 12 hours after operation. RESULTS: Myocardial glutathione and adenine nucleotides were correlated (p < 0.02) with preoperative LVEF both at T0 (r = 0.909 and 0.672) and T1 (r = 0.603 and 0.605). Oxidised glutathione released from the heart during reperfusion was inversely correlated with LVEF (r = -0.448, -0.466, and -0461 at T1, T2, and T3, p < 0.01), while reduced glutathione (r = 0.519 and 0.640 at T1 and T2) and glutathione redox ratio (r = 0.647, 0.714, 0.645, and 0.702 at T0, T1, T2, and T3) showed a direct correlation (p < 0.01). Lipid peroxidation at T1 was negatively related to LVEF (r = -0.492). CK-MB was also negatively related to LVEF (r = -0.440 at 4 h and -0.462 at 12 h). CONCLUSIONS: The capacity to counterbalance oxidative burst following ischaemia and reperfusion appears to be related to the functional ability of the heart.

Adenine Nucleotides↗
PubMed1998

Serum and bone concentrations of teicoplanin and vancomycin: study in an animal model.

Teicoplanin and vancomycin are antibiotics widely used in the therapy of bone and joint infections. The aim of this study was to compare bone and serum concentrations of each antibiotic in guinea pigs after administration of 50 mg/kg of teicoplanin or vancomycin by the intravenous route. Serum and bone concentrations were determined immediately before and 0.5, 1, 2, 6, 12 and 24 h after drug administration by means of high performance liquid chromatography. Teicoplanin concentrations were always higher than vancomycin levels. Area under the concentration/time curve was significantly greater for teicoplanin than for vancomycin. In bone, teicoplanin concentration increased up to 6 h, while vancomycin reached its peak after 2 h. Moreover, teicoplanin showed markedly higher levels at 6, 12 and 24 h than vancomycin. In conclusion, the ability of teicoplanin to penetrate bone in greater amount than vancomycin confirms the potential use of teicoplanin in the treatment of bone infections and in the prophylaxis of orthopedic surgery.

Analysis of Variance↗
PubMed1997

Role of leucocytes in free radical production during myocardial revascularisation.

OBJECTIVE: To evaluate the role of leucocytes in free radical production in patients with depressed or normal ejection fraction undergoing coronary bypass. DESIGN: Two randomised control trials. SETTING: Tertiary care centre. PATIENTS AND INTERVENTIONS: In the first study, 22 patients with ejection fractions of < or = 40% received blood cardioplegic reperfusion with (n = 11) or without (n = 11) leucocyte depletion. In the second study, 22 patients with ejection fractions > or = 45% received either leucocyte depleted (n = 11) or blood cardioplegia (n = 11). MAIN OUTCOME MEASURES: Glutathione, hypoxanthine, and lipid peroxidation products were measured in coronary sinus blood and plasma before aortic cross clamping and at 0, 15, and 30 minutes after unclamping. Haemodynamic variables and creatine kinase MB isoenzymes were monitored on the first postoperative day. Comparison between treatments was performed on difference (delta) between measurements at time 0 and at baseline, and on slopes obtained by fitting measurements after unclamping with a linear regression model. RESULTS: At unclamping no difference in delta for plasma glutathione redox ratio (oxidised/total glutathione, %) was observed between treated and control groups with low ejection fraction (delta = 16 (SD 8.39) and 24 (7.0) redox ratio %, respectively). Baseline value recovery rate (redox ratio %/min) was significantly faster in treated v control patients (slope -0.912 (0.380) v -0.158 (0.200), P < 0.005, respectively). Cardiac index showed a trend to greater improvement in the treated group (slope 0.04 (0.03) v 0.003 (0.002) 1/min/m2/h, P < 0.02, treated v controls, respectively). In patients with normal ejection fraction, leucocyte depletion did not result in significant improvement v controls. CONCLUSIONS: Leucocyte depletion seems to provide benefit only in patients with left ventricular dysfunction.

Aged↗
PubMed1997

Plasma mitomycin C concentrations determined by HPLC coupled to solid-phase extraction.

The aim of this study was to set up a method for quantification of plasma mitomycin C (MMC) concentrations during intravesical chemotherapy delivered in the presence of local bladder hyperthermia (HT). In comparison with existing methods, this assay, characterized by relative simplicity and efficiency, resulted in the facilitation of performance with nondedicated instrumentation or nonspecialized staff. Purification from plasma matrix was carried out by solid-phase extraction under vaccuum. The purified drug was then collected directly into the vials of the HPLC autosampler. Chromatographic analysis was performed on a reversed-phase C18 column with water:acetonitrile (85:15 by vol) as the mobile phase and the UV detector set at 365 nm. The use of porfiromycin as internal standard provided a method with good within-day precision (CV 6.0% at 5 micrograms/L, n = 6), linearity (0.5-50 micrograms/L), and specificity. The lower limit of detection (< or = 0.5 microgram/L) proved to be suitable for plasma pharmacokinetics monitoring in two tested patients treated with MMC + HT for superficial bladder cancer.

Antibiotics, Antineoplastic↗
PubMed1995

Influence of the 21-aminosteroid U74389F on ischemia-reperfusion injury in the rat.

We examined the effects of the administration of 21-[4-(2,6-di-1-pyrrolidinyl-4-pyrimidinyl)-1-piperazinyl]-pregna-1,4,9( 11)-triene-3,20-dione, monomethansulfonate (U74389F), a 21-aminosteroid and so-called lazaroid, that is characterized by an inhibitory activity against iron-dependent lipid peroxidation, on ischemia-reperfusion renal injury in a rat model. After either 60 or 90 min of ischemia, plus 2 or 24 h of reperfusion, kidneys were assayed for glutathione, adenine nucleotides and lipid peroxidation products. 60 min of ischemia produced too little oxidative stress and/or too much spontaneous recovery to allow visualization of the protective effect of the drug. 90 min of ischemia followed by reperfusion induced significant glutathione oxidation, the free oxidized glutathione to total glutathione redox ratio (%) being enhanced from 4.6 +/- 0.7% before kidney clamping to 11 +/- 1 and 8.6 +/- 1.4% at 2 and 24 h reperfusion, respectively. Treatment with the lazaroid provided significant protection against this oxidation (4.9 +/- 1.05% at 24 h reperfusion). Results of lipid peroxidation confirmed the antioxidant effect of the lazaroid. In conclusion this study provides evidence for a protective role of the tested lazaroid against ischemia-reperfusion renal injury in the rat.

Adenosine Triphosphate↗
PubMed1995

HPLC with o-phthalaldehyde precolumn derivatization to measure total, oxidized, and protein-bound glutathione in blood, plasma, and tissue.

This HPLC assay with o-phthalaldehyde precolumn derivatization is used to measure the total, oxidized, and protein-bound forms of glutathione in human blood, plasma, and rat tissue. Total glutathione (i.e., sum of reduced, oxidized, and protein-bound fractions) was determined after reduction with dithiothreitol and protein precipitation with perchloric acid (PCA). A preliminary selective blockage of free sulfhydryl groups with N-ethylmaleimide was necessary to evaluate the different oxidized forms. The assay showed high sensitivity (< 0.05 pmol injected) and good precision (within-day CVs of 5.5% to 6.4%), recovery (101% +/- 4%), and linearity (r > 0.999). Samples, after PCA acidification, were stable at room temperature and 4 degrees C for 3 days, and at -20 degrees C and -80 degrees C for > 1 month. The method (involving automated derivatization) not only is very rapid and simple but also allows immediate processing of many different biological samples.

Animals↗
PubMed1993

Ultrasonic evaluation of kidney volume in term and preterm infants.

Kidney volume in relation to gestational age, birthweight, and height was determined in 121 infants, 58 females and 63 males, with gestational ages from 23 to 43 weeks (mean, 33.3) and birthweight from 430 to 4600 gm (mean, 1982 gm). The kidney volume was measured using a real-time linear computed ultrasound scanner, with a 5 MHz transducer. The renal volume was calculated from outer kidney diameters using the volume formula for an ellipsoid. In the infants studied, mean volume of the right kidney was 6.0 ml (range, 1.4 to 13.8 ml), and of the left kidney 6.6 ml (range 1.5, to 15.6 ml), with no significant difference. A highly significant correlation was found between the volume of both kidneys and either gestational age, or birthweight, or height, with r values ranging from 0.81 to 0.92. The best correlation was observed with birthweight. No significant difference was found between males and females.

Birth Weight↗
PubMed1992

High-performance liquid chromatographic method with fluorescence detection for the determination of total homocyst(e)ine in plasma.

A high-performance liquid chromatographic method for the determination of total plasma homocyst(e)ine [H(e)] after reduction with sodium tetrahydroborate and precolumn derivatization with o-phthaldialdehyde is described. The analyses, carried out on a reversed-phase C18 column, were based on spectrofluorimetric detection. The sensitivity was 1 pmol per injection and the intra- and inter-assay relative standard deviations were 1.8% and 5%, respectively. The plasma H(e) concentration determined in 40 healthy volunteers (20-60 years old) was 12.4 +/- 2.9 microM (mean +/- S.D.), in good agreement with reference values.

Adult↗
PubMed1992

Total urinary hydroxyproline determined with rapid and simple high-performance liquid chromatography.

A precolumn derivatization method was optimized for rapid and specific analysis of total urinary hydroxyproline by HPLC. After an overnight hydrolysis, urine samples dried and reconstituted with the internal standard cysteic acid (in sodium hydrogen carbonate, pH 9.3) were derivatized with N,N-diethyl-2,4-dinitro-5-fluoroaniline (FDNDEA) at 100 degrees C for 20 min. The DNDEA-hydroxyproline adduct was separated on an Ultrasphere ODS column with a mobile phase of acetate buffer (containing triethylamine, 6 mL/L, pH 4.3) and acetonitrile (80/20, by vol), and was detected at 360 nm. A single run took 18 min with a hydroxyproline retention time of 7.3 min. The assay showed a linear response to hydroxyproline concentrations from 5 to 100 mg/L with a detection limit of 0.8 ng injected, corresponding to 2 mg/L in urine. Mean (SD) analytical recovery was 94.2 (13)% and 104 (9)% at 10 and 50 mg/L, respectively. Within-run and between-run CVs (n = 10) were 3.74% and 4.33%, respectively, for 25 mg/L. Results for samples (n = 50) analyzed by HPLC (y) vs ion-exchange chromatography with postcolumn ninhydrin reaction (x) correlated well: y = 0.98x + 1.02 (r = 0.985, Sxy = 3.13). In another comparison, involving 173 samples, a colorimetric procedure (Hypronosticon, x) gave slightly higher values than the HPLC method (y): y = 0.83x + 2.21 (r = 0.937, Sxy = 4.6).

Aniline Compounds↗
PubMed1990

Serum amino acid analysis with pre-column derivatization: comparison of the o-phthaldialdehyde and N,N-diethyl-2,4-dinitro-5-fluoroaniline methods.

We compared two pre-column derivatization methods, o-phthaldialdehyde (OPA) and N,N-diethyl-2,4-dinitro-5-fluoroaniline (FDNDEA), for analysis of serum amino acids by reversed-phase high-performance liquid chromatography. Separations took 102 and 106 min for FDNDEA and OPA (reconditioning included), respectively, allowing a very good resolution of 30 amino acids by the former process and 38 by the latter. Linearity, within- and between-day variability and advantages in terms of accuracy and speed were studied for both methods. Twenty serum samples from healthy volunteers were assayed with OPA, FDNDEA and with the reference method of ion-exchange and post-column ninhydrin reaction (amino acid analyser), which took 170 min. The correlation between OPA and ninhydrin was good for all the amino acids (r = 0.959) except for the last-eluting lysine. Good agreement was found for FDNDEA (r = 0.987), which appeared in general to be a highly reproducible technique. Both pre-column methods were more sensitive than the post-column ninhydrin method.

Adult↗
PubMed1990

Increased renal echogenicity in the neonate.

We report data on newborn infants with increased renal echogenicity observed at the Division of Neonatal Intensive Care of Pavia during a five-year period. Review of 1600 abdominal ultrasonic evaluations revealed 103 newborn infants (56 females and 47 males, with birth weight from 560 to 3700 g and gestational age from 25 to 42 weeks) whose kidneys showed increased echogenicity. Three patients with infantile polycystic kidney disease, two with renal candidiasis, three with dysplastic kidney and two with renal vein thrombosis showed diffuse hyperechogenicity. Three patients with hemolytic-uremic syndrome showed cortical hyperechogenicity. Increased medullary echogenicity was observed in 90 infants with renal disease secondary to perinatal asphyxia. In 76 of these patients the evaluation of renal echogenicity and the renal function improved, while in the remaining 14 newborns the renal alteration persisted until death.

Female↗
PubMed1989

Ultrasonic evaluation of kidney length in term and preterm infants.

Kidney length was evaluated by ultrasound in 132 healthy neonates with gestational ages from 27 to 42 weeks and birth weights from 790 to 4200 g. A highly significant correlation was found between the length of the kidneys and gestational age or birth weight.

Birth Weight↗
PubMedDate not supplied

Lack of in vitro and in vivo selection of bacterial resistance by roxithromycin.

The in vitro and in vivo selective pressure exerted by roxithromycin on Lancefield group A beta-haemolytic streptococci (GABHS) was investigated. In vitro antimicrobial activity on fifty GABHS strains was determined by the microdilution method and by boundary concentration (BC) determination. Insorgence of resistance was evaluated by redetermining MIC and BC after exposure to 16 x MIC roxithromycin concentration. In vivo insorgence of resistance was evaluated by MIC and BC determinations on the GABHS strain recovered from infected mice peritoneum, after treatment with 20 mg/kg roxithromycin. The roxithromycin serum kinetics was established in healthy and infected mice. Neither significant changes in GABHS MIC or BC after in vitro or in vivo exposure to roxithromycin nor a difference in roxithromycin serum levels between healthy and infected mice were detected, suggesting that the roxithromycin selection of resistance in GABHS is low.

Animals↗
PubMedDate not supplied

Comparative effect of thiamphenicol glycinate, thiamphenicol glycinate N-acetylcysteinate, amoxicillin plus clavulanic acid, ceftriaxone and clarithromycin on pulmonary clearance of Haemophilus influenzae in an animal model.

BACKGROUND: Thiamphenicol glycinate (TG) and its derivative thiamphenicol glycinate N-acetylcysteinate (TGA) could be a valid therapeutic option in the treatment of respiratory tract infections. METHODS: Time-kill curves of TG and TGA and pulmonary clearance in Haemophilus influenzae infected guinea pigs were compared with those of clarithromycin, ceftriaxone and amoxicillin plus clavulanic acid. RESULTS: The bacterial activities of the tested antibiotics were comparable. When compared to the control group, lung bacterial counts were significantly lower for the TGA group at 3 h vs. controls, while for the other treatments, significant decreases were recorded after 6 h. All drugs showed a log count of <2.0 at 24 h with respect to the control while at 48 h all groups demonstrated a log count of <2.0. CONCLUSIONS: Although the in vitro activity of the tested drugs evaluated by time-kill curves seemed comparable, some pharmacokinetic and pharmacodynamic characteristics of TGA contribute to improving the resolution of the infective process.

Acetylcysteine↗