PubMed Health⌕ Search

Biomedical subjects

A Barbieri

Publications and source records attributed to A Barbieri.

At least 55 records · Page 3Linked to original sources
PubMed1999

Liver ischemia modifies the concentration of plasmatic catecholamines after reperfusion in the rat.

Pulmonary hypertension is one of the most frequent and severe consequences of liver ischemia. The aim of this study is to evaluate the presence of humoral vasoactive mediators, generated during liver ischemia, which could be able to determine the onset of pulmonary hypertension. Thus, we evaluated the plasmatic concentration of catecholamines (adrenaline, noradrenaline, dopamine) during the immediate reperfusion period. Wistar rats were used. Animals (n = 89) were divided into four groups. Group 1 served as control (sham-operated). In group 2 animals underwent 60 min of left hepatic exclusion. In group 3 animals underwent to bilateral adrenectomy. In group 4 animals had both bilateral adrenectomy and liver ischemia. Ischemia in group 2 and 4 was induced by interrupting the vascular supply to the left and median lobes, so avoiding the use of a portal shunt. Blood samples were collected from the suprahepatic inferior caval vein immediately after reperfusion. Strips of the main pulmonary artery were put into an isolated organ bath and tested for the response to noradrenaline, adrenaline and plasma samples. Plasma samples collected after ischemia caused a significantly greater (p < 0.01) contraction of the pulmonary artery compared to controls. Plasma samples collected after adrenectomy caused a weak contraction which was not different from that obtained in the adrenectomy + ischemia group. Plasma concentrations of catecholamines after liver ischemia were significantly increased in the control group (p < 0. 01). In adrenectomized rats only the adrenaline level was greatly reduced. However ischemia did not increase plasma catecholamines as it occurred in sham-operated rats.

Animals↗
PubMed1999

Diabetes mellitus and cardiovascular complications: pathophysiological peculiarities and therapeutic implications.

Diabetes mellitus is a chronic illness frequently associated with cardiovascular complications. The cardiologist must therefore play an important role in the management of diabetic patients, aware of the different natural history of the insulin-dependent and non-insulin-dependent forms, as well as of the pathophysiological peculiarities of the disease which requires particular diagnosis and therapy. Unfortunately, treatments which have proved to be most effective are still underused. Cardiovascular complications in diabetic patients are aggravated by higher morbidity and mortality rates than in the general population. In an attempt to prevent major cardiovascular events, the cardiologist must identify those patients at greater risk, particularly those with asymptomatic coronary heart disease.

Acute Disease↗
PubMed1998

Detection of xanthine oxidase activity products by EPR and HPLC in bronchoalveolar lavage fluid from patients with chronic obstructive pulmonary disease.

Xanthine oxidase (xanthine: oxygen oxidoreductase, EC 1.1.3.22), a molybdenum-containing hydroxylase that produces superoxide and uric acid from purine substrates and molecular oxygen, is involved in the oxidative stress underlying several human pathologies including lung diseases. An enzymatic activity similar to xanthine oxidase was previously reported in bronchoalveolar lavage fluid of patients with chronic obstructive pulmonary disease (COPD-BAL), by fluorometric analysis of DNA unwinding and cytochrome c reduction kinetics. Here we report the detection of xanthine oxidase activity products by electron paramagnetic resonance (EPR) in presence of the spin-trap 5,5-dimethyl-1-pyrroline N-oxide (DMPO) and reversed-phase high-performance liquid chromatography (RP-HPLC) in COPD-BAL (n = 14, average age of patients 65 years, range 38-81) and BAL from healthy nonsmoker controls (n = 6, average age 64 years, range 44-73). Superoxide DMPO adducts were detected in COPD-BAL and in an in vitro system containing xanthine and xanthine oxidase (XA/XO), but not in BAL controls and when superoxide dismutase (SOD, 1000 I.U./ml) was added to COPD-BAL. The HPLC analyses after addition of xanthine showed production of uric acid in COPD-BAL and in the XA/XO system but not in BAL controls. These results support the involvement of xanthine oxidase in the mechanisms of superoxide production by BAL supernatant, which increases oxidative stress in chronic obstructive pulmonary disease.

Adult↗
PubMed1998

Pharmacological characterization of alpha-adrenoceptors that mediate contraction in splenic artery strips from the pig.

The alpha-adrenoceptors that mediate contractions in strips of splenic artery from the pig were characterized by the use of selective agonists and subtype-selective antagonists. Noradrenaline, the alpha1-selective agonist phenylephrine and the alpha1-/alpha2-agonist oxymetazoline caused the preparations to contract with potency (pD2) values of 6.94, 6.14 and 7.27, respectively. Compared to noradrenaline, phenylephrine and oxymetazoline induced 93% and 78% of noradrenaline maximum effect. Conversely, the two alpha2-selective agonists clonidine and B-HT 920 induced only 31% and 13% of noradrenaline maximum effect. B-HT 920 only marginally contracted the tissue even when it was precontracted with phenylephrine. The alpha2-selective antagonist yohimbine antagonized oxymetazoline- and phenyleprine-induced contractions with affinity (pA2) values (6.80 and 6.74, respectively) consistent with alpha1-adrenoceptor interaction. This suggests that the pig splenic artery possesses only functional alpha1-adrenoceptors. The alpha1-adrenoceptor antagonists of varying subtype selectivities like WB-4101, 5-methylurapidil, benoxathian and BMY 7378 competitively antagonized phenylephrine-induced contractions with affinity values of 9.46, 8.26, 9.06 and 6.91, respectively. These values correlated highly with published affinity values for functional alpha1A-adrenoceptors (r=0.92) and alpha1a-clones (r=0.94) and less well with affinity values for functional alpha1B-adrenoceptors (r=0.84) and alpha1b-clones (r=0.87). Conversely, correlation with functional alpha1D-adrenoceptors (r=0.26) and alpha1d-clones (r=0.33) was poor. In addition the alpha1D-selective antagonist BMY 7378 had a low affinity value compared to that reported for alpha1D-adrenoceptors. Therefore, based on correlation studies, the plot that resembled the line of equal values most closely was that for the alpha1A-subtype. The alpha1A-selective antagonist RS-17053 antagonized phenylephrine-induced contractions in an apparently non-competitive manner and gave an apparent pA2 value of 7.06 which is similar to the "low" affinity values reported in other alpha1A-containing tissues. Exposure to the irreversible alpha1B/D-antagonist chloroethylclonidine slightly decreased maximum response to phenylephrine without significantly affecting its potency value, indicating that the phenylephrine response is substantially chloroethylclonidine-insensitive. It is concluded that splenic artery strips from the pig contract in response to phenylephrine through activation of alpha1-adrenoceptors which display the pharmacological profile of the alpha1A-subtype for which the recently reported alpha1A-selective antagonist RS-17053 shows low affinity. Evidence for contribution of the alpha1B-subtype in the overall contractile response is elusive while no evidence was obtained for the involvement of the alpha1D-subtype. The contribution of functional alpha2-adrenoceptors to the contractile response was ruled out.

Adrenergic alpha-1 Receptor Agonists↗
PubMed1998

Quantitative changes in pharmacodynamic parameters of noradrenaline in different rat aorta preparations: influence of endogenous EDRF.

1. The aim of the present study was to assess the role of endothelial cells in the modulation of vasocontractile responses to noradrenaline in rat isolated aorta when cut as standard helical strips or as ring segments. 2. Noradrenaline-potency in helical strip preparations evaluated as -logEC50 was greater than that obtained in endothelium-intact ring preparations (9.45 +/- 0.28 versus 8.69 +/- 0.09, respectively) (P < 0.05). The maximum contractile response of helical strips was significantly higher than the response of ring preparations (P < 0.05). 3. Subsequent experiments were performed on helical strips and ring preparations where the endothelium was removed by rubbing the luminal surface of the aorta with filter paper. Removal of the endothelium potentiated the noradrenaline-induced contraction in ring preparations, but not in the helical strips. 4. The nitric oxide synthase inhibitors L-NAME (3 x 10(-5)-3 x 10(-4) M) or L-NNA (1 x 10(4)-3 x 10(-4) M) which were added to the tissue bath potentiated the noradrenaline-induced contraction in the endothelium-intact ring preparations, although only L-NNA induced a statistically significant potentiation. Both L-NAME and L-NNA had no effect on the noradrenaline-contraction induced in rings without endothelium, or in helical strips with or without endothelium. 5. Vascular acetylcholine-induced relaxation is dependent on endothelium derived relaxing factor (nitric oxide). Acetylcholine (10(-9)-10(-6) M) induced a concentration-dependent relaxation in noradrenaline preconstricted intact rings. The relaxant response was strongly reduced by L-NAME (3 x 10(-5)-1 x 10(-4) M). The relaxant response to acetylcholine was very weak in ring and helical strip preparations without endothelium, but also, surprisingly, in unrubbed standard helical strips. 6. The present results suggest that the endothelium of standard helical strip preparations may be greatly damaged, a view confirmed by morphological studies. The structural and functional damage of the endothelium induced very important changes in pharmacodynamic parameters such as in the potency and the maximal responses of vascular preparations to noradrenaline. Therefore, caution must be observed when the potency and intrinsic activity of agonists evaluated on different preparations are compared, even if these come from the same vascular segment.

Animals↗
PubMed1998

Effect of calcium antagonists on the response to noradrenaline in the whole and bisected rat vas deferens.

1. The present study was carried out to look at the effect of different calcium antagonists on the response to noradrenaline in the whole and bisected rat vas deferens considering that the response consisted of three components (I) the phasic response (II) the tonic response and (III) the spikes (rhythmic contractions). 2. Nifedipine (3 x 10(-9)-1 x 10(-7) M) inhibited all the components at the same concentration range, verapamil (1 x 10(-7)-1 x 10(-5) M) inhibited the phasic and tonic response but not the rhythmic activity. This latter component, at a certain concentration range and especially in the prostatic portion was markedly potentiated. Diltiazem and flunarizine lay in an intermediate position. 3. Papaverine, a Ca2+ antagonist that acts mainly intracellularly, inhibited preferentially the tonic component; ryanodine was practically inactive. 4. Cromakalim inhibited only partially the phasic and tonic components but totally inhibited the rhythmic contractions. 5. These results can be explained by postulating two types of calcium channels opened by alpha-adrenoceptor stimulation. The first one is verapamil- and nifedipine-sensitive and allows the entry of Ca2+ directly available for the contraction and responsible for the phasic and partially responsible for the tonic component. The second channel is merely nifedipine-sensitive and allows the entry of Ca2+ trigger which can release Ca2+ from intracellular sites: the mobilized Ca2+ is able to sustain the tonic component and is the main one responsible for the rhythmic activity. There is the possibility that this second channel is associated with ATP-sensitive K+ channels.

Animals↗
PubMed1998

[Ileal conduit: our experience].

In the last 100 year, many progresses have been done in the ileal urinary diversion after cystectomy. Although the interest for the continent urinary diversion has increased enormously in the last ten years, the ileal conduit still represents the golden standard. We report our experience.

Adult↗
PubMed1998

[The hemodynamic effects of the in-vivo administration of insulin-like growth-factor I].

BACKGROUND: Recent studies have demonstrated that IGF-I has several biological activities that correlate with the GH axis, by acting as a cell protecting factor and a promoting compound in different tissues and organs. Our latest findings have demonstrated a potential application of IGF-I in the treatment of postischemic renal injury, which frequently appears after a kidney transplant. The beneficial effect of the renal postoperative recovery probably correlates with the regulation of the vascular tone, in which IGF-I plays a role with other cytokines. However, this rises the question whether IGF-I has any effect on the general hemodynamic status. This study was designed to underline the intraoperative hemodynamic effect of exogenous IGF-I in an experimental setting of renal transplantation in swine. METHODS: Twelve female swine underwent a left renal autotransplantation. At the reperfusion the animals were separated in two groups. Group one served as control. Group two received 400 micrograms of IGF-I (added to the flushing solution). The animals were kept under complete hemodynamic monitoring over the operation. RESULTS: Among the different parameters studied (mean arterial pressure, mean pulmonary arterial pressure, pulmonary wedge pressure, central venous pressure, cardiac output, oxygen extraction ratio, systemic vascular resistance, oxygen delivery and oxygen consumption), any statistically significant difference between group one and two were observed. CONCLUSIONS: While the clinical administration of IGF-I requires further studies, the in vivo administration of this peptide is apparently well tolerated, and does not cause any hemodynamic instability to the operation.

Analysis of Variance↗
PubMed1998

[Bilateral renal oncocytoma. A clinical case and review of the literature].

Renal oncocytoma is an epithelial tumour of the kidney, originally considered benign neoplasm, but now it is thought have a limited but real malignant or metastatic potential. Usually monolateral, in 6% of cases it is bilateral in a synchronous or metachronous way. A case of bilateral renal oncocytoma in a 56-year-old woman, observed by chance during a follow-up carried out after breast cancer is described. The etiopathogenic and clinical-therapeutic aspects of this neoplasm are examined, and the conclusion is drawn that the most correct therapeutic approach must aim at both the protection of kidney function and complete removal of the tumour.

Adenoma, Oxyphilic↗
PubMed1998

[Eosinophilic cystitis: an incidental diagnosis. An underdiagnosed entity].

The authors report on two cases of eosinophilic cystitis diagnosed by chance, are reported. Both patients had suffered from prostatic and vesical diseases. Since the endoscopic appearance and clinical manifestation of this disease are aspecific, the diagnosis of eosinophilic cystitis is always made on histological specimen. Even if it has been described as a rare entity, personal opinion is that the real incidence of eosinophilic cystitis is underestimated. The main features of pathogenesis and therapy are also described.

Aged↗
PubMed1998

[Sertoli cell tumor. Case report].

A case of Sertoli cell tumor is described. It represents 1% of testicular neoplasms. Its clinical features, histology, histogenesis and treatment on the basis of the current literature are reported. The malignant potential of this kind of tumor is also stressed.

Adult↗
PubMed1997

Insulin-like growth factor-I ameliorates delayed kidney graft function and the acute nephrotoxic effects of cyclosporine.

BACKGROUND: Delayed graft function (DGF) is a relatively common complication after cadaveric renal transplantation. The adverse effect of DGF on long-term graft survival has lead to intensive efforts to reduce ischemic graft injury. In this study we examined the effects of a new protective treatment based on insulin growth factor (IGF)-I. We evaluated the impact of the treatment on renal recovery and on the nephrotoxicity that is a common side effect of mainstream immunosuppressants. Because therapy with IGF-I or the analog des(1-3)IGF-I is effective in treating experimental ischemic renal failure, these peptides may be useful as perspective clinical treatments. METHODS: We have addressed three areas relating to the potential use of IGF-I and its analog des(1-3)IGF-I. First, because of the immunogenic properties of IGF-I, we assessed the effect of des(1-3)IGF-I on the rejection of skin allografts in Lewis rats. Next we determined whether treatment with des(1-3)IGF-I influences the early function of transplanted kidneys in a model of DGF induced by a combination of warm and cold ischemia. Finally we tested whether IGF-I protects against acute cyclosporine nephrotoxicity. RESULTS: Des(1-3)IGF-I did not accelerate the rejection of the skin grafts (P=0.57). The administration of this peptide in a model of syngenic renal transplant improved the early function of the graft. Postoperative values of creatinine and blood urea nitrogen were significantly better (P<0.05) in treated animals. IGF-I also ameliorated the nephrotoxicity of cyclosporine, with better values of creatinine and blood urea nitrogen (P<0.05). CONCLUSIONS: In evaluating this study it should be recognized that the animal models studied, although widely used, differ from the human condition. However, IGF-I and des(1-3)IGF-I exhibit properties that strongly suggest their value in preventing clinical DGF, and they deserve further studies.

Animals↗
PubMed1997

M4 muscarinic autoreceptor-mediated inhibition of -3H-acetylcholine release in the rat isolated urinary bladder.

A pharmacological analysis was carried out in the rat urinary bladder to assess the nature of muscarinic receptors subtypes functionally involved in the negative feedback mechanism regulating acetylcholine (ACh) secretion from postganglionic cholinergic nerve terminals and in smooth muscle contraction. Bladder strips were preincubated with 3H-choline, and the electrically evoked [3H]ACh release was detected simultaneously with contraction in the absence of acetylcholinesterase inhibitors. The effects were compared of seven muscarinic antagonists on [3H]ACh secretion (prejunctional effect) and muscle contraction (postjunctional effect). The rank order of postjunctional potencies (-log EC50) for the seven antagonists (atropine > 4-diphenylacetoxy-N-methylpiperidine methiodide (4-DAMP) > hexahydrosiladiphenidol hydrochloride (HHSiD) > tripitramine > pirenzepine > AF DX-116 > methoctramine) as well as their postjunctional affinity estimates (pA2) are in keeping with the notion that muscarinic receptors responsible for bladder contraction belong to the M3 subtype. The M3 subtype-preferring 4-DAMP and HHSiD did not discriminate between prejunctional and postjunctional effects. The M2/M4 subtype-preferring antagonists tripitramine, methoctramine and AF-DX 116 were more potent in facilitating the evoked [3H]ACh release than in inhibiting the contractile response. The rank order of prejunctional potencies was atropine > 4-DAMP > tripitramine > HHSiD > methoctramine > AF-DX 116 > pirenzepine, indicating the involvement of M4 receptors. Furthermore, when potency relationship was determined by correlating prejunctional-log EC50 values with published constants for cloned and natives muscarinic receptor subtypes, the correlations were significant for both M4 and M5 subtypes, but the best correlation found (P < .001) was for the M4 subtype. These findings suggest that the negative feedback mechanism inhibiting the release of ACh in the rat urinary bladder is mediated by prejunctional autoreceptors of the M4 subtype.

Acetylcholine↗
PubMed1997

[Valsalva leak point-pressure (LPP) and maximal urethral closure pressure (MUCP) in women with stress urinary incontinence (SUI)].

One-hundred and twenty-two women with USI have been evaluated with clinical examination and urodynamics and divided in two groups: only in 74 patients with urinary loss during the Valsalva manoeuvre, LPP was compared to MUCP by linear regression analysis and its ability (cut-off = 60 cmH2O) to predict a MUCP < or = 20 cmH2O was tested. Weak correlations were observed between MUCP and LPP (r = 0.56). Fifty-two patients presented a LPP < or = 60 cmH2O, in 6 of them MUCP was < or = 20 cmH2O; none with LPP > 60 cmH2O showed a MUCP < or = 20 cmH2O. Median MUCP and intravesical pressures at the instant of leakage of patients with LPP < or = 60 cmH2O were significantly different from those of patients with LPP > 60 cmH2O (p < 0.01). The specificity and positive predictive value of LPP < or = 60 cmH2O for the detection of a "low pressure urethra" were respectively 32% and 11.5%, while sensibility and negative predictive value were 100%. LPP can not be regarded as a specific test for urethral sphincteric deficits. For its sensibility, it can be an useful screening tool for patients at high risk of type III urinary incontinence.

Aged↗
PubMed1997

[Value and limitations of transrectal ultrasonography and computer tomography in preoperative staging of prostate carcinoma].

A careful evaluation of local tumoral extension is mandatory in patient selected for radical surgery for prostate cancer. Nevertheless, prostatic imaging, achieved with transrectal ultrasonography (TRUS) and CT scan, is often unable to stage accurately the disease. The Authors report a retrospective analysis of 43 patients treated with radical retropublic prostatectomy: their findings support the idea that both TRUS and CT scan are unable to define the extent of the tumor, reaching respectively accuracies of 38 and 46%. From these data they conclude that CT can be excluded from the preoperatory workup of prostate cancer, except in selected patients, at high risk of nodal metastasis on the basis of PSA. TRUS is the mainstay of prostate cancer diagnosis and staging because it guides transrectal biopsies, but any conclusion made exclusively on the base of its imaging seems not reliable.

Aged↗
PubMed1997

[State of the art in Nd:Yag laser treatment of benign prostatic hyperplasia].

Laser energy is widely used in medical sciences nowadays. Recently it has gained importance in urology as an alternative treatment, less invasive than conventional surgical approaches, to benign prostatic hypertrophy (BPH). The Authors present a review of the literature describing the different approaches to the laser treatment of BPH: visual laser ablation of the prostate (VLAP), TULIP, contact vaporization and interstitial laser therapy. They try to show vantages and limitations of this technique respect to conventional surgery. They also present their personal experience with VLAP. They conclude that prostate laser therapy is an alternative to TURP for patients suffering for uncomplicated BPH of small to medium volumes (< 40 ml). According to literature's data and personal experience, it seems that VLAP, the easiest technique, is able to achieve the best results.

Humans↗