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Biomedical subjects

S Taddei

Publications and source records attributed to S Taddei.

At least 19 recordsLinked to original sources

Analysis of risk factors for early hepatic artery thrombosis after liver transplantation. Possible contribution of reperfusion in the early morning.

BACKGROUND: Since the incidence of myocardial infarction and other cardiovascular ischaemic events is highest in early morning, on account of a relative hypercoagulable state occurring in this time period, an attempt was made to test whether reperfusion of the hepatic artery at this time of the day, at liver transplantation, produces an increased risk of early thrombosis. METHODS: The records of 255 consecutive patients receiving a first transplant for chronic liver disease were retrospectively analysed. As possible risk factors, for early post-operative thrombosis (<30 days from transplantation), several medical and surgical parameters were taken into consideration. Arterial reperfusion was considered to have taken place at a time of high coagulability when occurred between 6.00 a.m. and 10.00 a.m. on the basis of previous reports. RESULTS: Logistic regression identified donor age (OR for age >60: P=0.017), bench reconstruction of the artery (OR: 5.06, P=0.013) and time of high coagulability at reperfusion (OR 2.93, P=0.087), as independently associated with early hepatic artery thrombosis. CONCLUSIONS: The present findings identified three independent predictors of early hepatic thrombosis, warranting stricter post-surgical follow-up of patients presenting such conditions. Interestingly, these factors are consistent with arterial reperfusion in the early morning being associated with an increased risk of early hepatic artery thrombosis, suggesting relative coagulative imbalances to provide a contribution in the pathogenesis of this severe complication of liver transplantation.

Blood Coagulation↗

Endothelial function in young subjects with vaso-vagal syncope.

BACKGROUND: The aim of this study was to determine whether endothelial function and inappropriate peripheral vasomotion have a significant role in the pathogenesis of neurally mediated syncope. METHODS: In 16 patients (mean age 28.2+/-5.8 years) with previous vaso-vagal syncope and in matched healthy subjects, endothelium-dependent flow-mediated dilation (FMD) and endothelium-independent response to glyceryl trinitrate (GTN), 25 mug, were measured in the brachial artery from high-resolution ultrasonography. Heart rate variability (HRV) analysis at rest and during tilt test was compared between two groups. RESULTS: In the subjects with positive tilt test, all HRV parameters were significant higher respect to subjects with negative tilt test (P<0.001). The patients with positive tilt test, showed persistent, marked variability of heart rate (HR), due to increased vagal activity with withdrawal sympathetic tone and consequently reduction of blood pressure (BP) (-30.4+/-4.2 mmHg, P<0.001) accompanied by a decrease in HR (-24.3+/-4.5 beats/min, P<0.001) compared to negative tilt test subjects. These findings prove the real presence of vagal hypertone in patients with syncope. In our study, HR reached values lower than 40 beats/min. FMD in patients with neurally mediated syncope were significantly greater than those in controls (respectively, 9.2+/-2.8% vs. 4.6+/-1.4%, P<0.01) whereas no differences were shown in the response to GTN (18.4+/-4.4% vs. 16.1+/-4.2%, n.s.). CONCLUSIONS: The augmented endothelial function and the abnormal vasodilation of peripheral arteries in association with bradycardia play an important role in the development of vaso-vagal syncope in young subjects.

Adult↗

Ambulatory blood pressure monitoring and endothelium-dependent vasodilation in the elderly athletes.

AIM: Regular exercise is a key component of cardiovascular risk prevention strategies, because it is associated with a variety of beneficial metabolic and vascular effects that reduce mortality and the incidence of cardiovascular adverse events. Endothelium plays an important role in the local regulation of vascular tone and structure, mainly by nitric oxide (NO) synthesis and action. Aim of the present study was to evaluate in elderly athletes the effect of regular aerobic exercise on arterial blood pressure (BP) and on endothelium-dependent flow-mediated dilation (FMD) of the brachial artery. METHODS: The study population included 30 male subjects (mean age 65.6+/-5.6 years), who had practiced endurance running at a competitive level for at least 40 years, and 28 age- and sex-matched subjects (mean age 64.5+/-4.5 years) with sedentary lifestyle and free of cardiovascular disease. Athletes and control subjects underwent standard 12-lead ECG, clinic BP, 24-h ambulatory BP monitoring and endothelium-dependent FMD and endothelium-independent response to glyceryl trinitrate (GTN), 400 microg, in the brachial artery by high-resolution ultrasonography. RESULTS: Systolic clinic and ambulatory 24-h BP were significantly lower in the athletes, than in the controls (P<0.001, respectively). Systolic and diastolic 24-h BP variability, when assessed either by the standard deviation (S.D.), or by the coefficient of variation (CV), were also significantly lower in the athletes (P<0.01). The athletes also had a lower 24-h, day-time and night-time heart rate (HR) (P<0.01), as well as a lower HR variability (P<0.01). As regards circadian BP change, the %Delta was statistically significant greater in athletes (P<0.05). Elderly athletes showed higher FMD than elderly sedentary subjects (P<0.001), whereas no differences were shown in the response to GTN. CONCLUSIONS: Our results, suggest that long-term physical activity can counteract the age-related endothelial dysfunction that characterizes sedentary aging, preserving the capacity of the endothelium-dependent vasodilation and reduces BP values improving arterial pressure control.

Aged↗

Opioid-related side-effects after intrathecal morphine: a prospective, randomized, double-blind dose-response study.

BACKGROUND AND OBJECTIVE: The aim of this prospective, randomized, double-blind investigation was to assess the dose-effect characteristics of postoperative nausea and vomiting after intrathecal administration of small doses of morphine (from 0.015 to 0.25 mg) in opioid-naïve, non-surgical patients. METHODS: With Ethic Committee approval and written informed consent 144 opioid-naïve patients suffering from non-cancerous chronic back-pain, and receiving intrathecal morphine as diagnostic test for their chronic pain, were randomly allocated to receive intrathecal injection of 0.015 mg (Group I, n=25), 0.03 mg (Group II, n=30), 0.06 mg (Group III, n=31) or 0.25 mg (Group IV, n=33) morphine. The control group consisted in 25 further patients not included in the dose-effect study and receiving a placebo injection of normal saline in the interspinous ligament. A blinded observer recorded the occurrence of pruritus, nausea, vomiting, urinary retention and respiratory depression (respiratory rate<6 bpm) at 2, 4 and 24 h after injection. RESULTS: Clinically significant pain relief was observed in all patients receiving intrathecal morphine but only six patients (25%) of the control group (P=0.0005). The incidence of pruritus was lower in patients of Groups III (6%) and IV (3%) than in Groups I (12%) and II (20%) (P=0.002). The incidence of nausea and vomiting was higher at 2- and 4-h observation times, and decreased 24 h after intrathecal injection. Surprisingly, nausea was more frequent in Groups I (56%) and II (50%) than in Groups III (33%) and IV (24%) (P=0.0005). Vomiting was higher in patients receiving morphine than in control group, but without differences among the four doses. No urinary retention was observed in the control group, while 2 h after intrathecal injection urinary retention was observed in 20-40% of cases, and decreased to less than 10% 24 h after spinal injection without differences among the four doses. CONCLUSIONS: The onset and incidence of minor opioid-related side-effects after intrathecal morphine administration do not depend on its dose, occurring with even very small doses of morphine. Accordingly, they can be considered as a patient-dependent effect of the drug, suggesting the presence of a primary dose-independent excitatory component that might be related to the theory of the bimodal activation of opioid receptors. The very low incidence major respiratory depression prevents us from drawing any conclusion about the dose-effect relationship for this side-effect, and further properly powered studies should be advocated to evaluate major respiratory depression after spinal morphine.

Aged↗

[Diagnosis of renal cysts].

Evaluation and management of renal cysts Renal cystic diseases are a heterogeneous group of conditions including heritable, developmental, and acquired disorders. They are united by the presence of microscopic or giant fluid-filled cavities and affect both children and adults. The definitive diagnosis of many of the renal cystic diseases requires clinical, radiological, pathological, and genetic analysis. A precise diagnosis is essential for prognosis, treatment, and future genetic counselling.

Cysts↗

Is Hyperhomocyst(e)inemia a humoral predictor of coronary heart disease?

Elevated plasma homocyst(e)ine levels have prothrombotic and proatherosclerotic effects. Data from prospective studies indicated that plasma homocyst(e)ine acts as a modest independent predictor of coronary heart disease. At present, no conclusive data are available on the possible interaction between hyperhomocyst(e)inemia and hypertension and the occurrence of cardiovascular events. Recent longitudinal studies in high risk patients indicated that hyperhomocyst(e)inemia is strongly associated with recurrent cardiovascular events. However, this finding is not in line with the few available data from prospective studies, which failed to observe a protective role of homocyst(e)ine-lowering therapy in secondary prevention of cardiovascular events. Future results from ongoing larger trials are expected to provide more definitive answers concerning the need to support the routine use of folic acid in patients with CHD. Since the definitive impact of mild hyperhomocyst(e)inemia on coronary heart disease is still to be established, widespread determination of homocyst(e)ine levels is not needed in a general population at the present time. In contrast, knowledge of homocyst(e)inemia may be important for specific groups of individuals, such as high risk patients, and for those patients in whom traditional risk factors do not appear to account for an increased incidence of cardiovascular events.

Clinical Trials as Topic↗

Effect of levothyroxine replacement on lipid profile and intima-media thickness in subclinical hypothyroidism: a double-blind, placebo- controlled study.

Subclinical hypothyroidism (sHT) is associated with dyslipidemia and enhanced cardiovascular risk. We assessed carotid artery intima-media thickness (IMT, high-resolution ultrasonography) and lipoprotein profile in 45 sHT patients (aged 37 +/- 11 yr) at baseline and after 6 months of randomized, placebo-controlled L-T(4) replacement. In comparison with 32 age- and sex-matched controls, sHT patients had elevated total and low-density lipoprotein (LDL) cholesterol and ApoB levels (P = 0.002, P = 0.0007, and P = 0.01, respectively) and higher mean-IMT values (P < 0.0001). In stepwise regression analysis, mean-IMT was positively related (r(2) = 0.71, P < 0.0001) to age, TSH, and LDL cholesterol. L-T(4) replacement significantly reduced both total and LDL cholesterol (P < 0.0001 for both) and mean-IMT (by 11%, P < 0.0001). The decrement in IMT was directly related to the decrements of both total cholesterol and TSH (P = 0.02 and P = 0.0001, respectively). We conclude that early carotid artery wall alterations are present in sHT patients. Whether such IMT increase is related to an early atherosclerotic involvement of the arterial wall cannot be clearly decided on the basis of the present results. However, the fact that L-T(4) replacement therapy was able to improve both the atherogenic lipoprotein profile and intima-media thickening suggests that lipid infiltration of arterial wall may represent a major mechanism underlying IMT increase in subclinical hypothyroidism.

Adult↗

Bacteriologic findings in ostrich (Struthio camelus) eggs from farms with reproductive failures.

From January 2001 to December 2002, 543 ostrich eggs were submitted for bacteriologic investigation. The eggs were laid by 387 domesticated ostriches that suffered fertility disorders and that came from 44 farms located in different areas of Northern and Central Italy. Microbiologic investigations showed bacterial isolation in 105 (19.3%) of 543 eggs examined, with a high prevalence of enterobacteria from albumen and yolk. In only a few cases did bacterial isolation result from yolk or albumen alone. An antibiotic sensitivity test was conducted on isolates by the Kirby-Bauer disc diffusion method. This is the first report regarding the microbiologic status of eggs from ostrich farms located in different Italian regions.

Animals↗

Practice of opportunistic PSA screening in the Florence District.

The widespread use of the prostate-specific antigen (PSA) test had a great impact on the rise of incidence of prostate cancer. The magnitude of opportunistic screening by PSA varies across countries, being highest in the US, and considerably lower in Europe. To estimate the opportunistic use of PSA over the period of one year (2000) in the District of Florence, we analysed the Regional Database of diagnostic exams. According to the Regional Database, subjects having at least one PSA test during the year 2000 ranged from 5.8 to 6.7%, 8.8-10.8%, 11.7-15.0%, 16.5-22.3%, 18.0-24.3%, 17.0-23.8% and 14.1-18.3% in the 50-54, 55-59, 60-64, 65-69, 70-74, 75-79 and >79 years age groups, respectively. Minimum and maximum values are reported according to exclusion or inclusion of PSA determinations with incomplete subject identification data. Such a high use of PSA should deserve special attention from both the medical and health care provider community. The aim of the present study was to evaluate the frequency of opportunistic screening by PSA in the District of Florence in the general population.

Aged↗

Mechanisms of endothelial dysfunction: clinical significance and preventive non-pharmacological therapeutic strategies.

Endothelium-derived NO is not only a potent vasodilator but also inhibits platelet aggregation, vascular smooth muscle cell migration and proliferation, monocyte adhesion and adhesion molecule expression, thus protecting the vessel wall against the development of atherosclerosis. Cardiovascular risk factors are associated with an imbalance of the redox equilibrium towards oxidative stress and, therefore, impair the integrity of the endothelium, leading to endothelial activation which involves blunted endothelium-dependent vasodilation (vasodilator dysfunction) as well as inflammatory processes extending to the milieu within the whole vasculature, making plaques prone to rupture. In prospective studies endothelial dysfunction is associated with increased incidence of cardiovascular events. Thus, the prevention of endothelial dysfunction can determine a strong advantage in the clinical outcome of patients with cardiovascular risk factors. Several non-pharmacological interventions can prevent endothelial dysfunction or improve impaired endothelium-dependent vasodilation. Probably the most effective non-pharmacological measure is represented by aerobic physical activity, which can reduce production of oxidative stress associated to increasing age. Moreover, physical activity can improve endothelial dysfunction even in patients with cardiovascular risk factors such as essential hypertension. In addition several other approaches, including vitamin and fish oil supplementation, or tea and red wine consumption, can lead to an improvement of endothelium-dependent vasodilation, possibly by a restoration of NO availability. It is worth noting that most of non-pharmacological measures act by preventing or reducing oxidative stress.

Biological Factors↗

Evaluation of susceptibility of Mycobacterium bovis to antituberculous drugs by radiometric BACTEC 460TB system.

Susceptibility of Mycobacterium bovis strains to antituberculous drugs (isoniazid and rifampin) was detected by radiometric BACTEC 460TB system. M.bovis strains were isolated from tissue samples showing tuberculous lesions collected at an abbattoir from cattle belonging to 47 tuberculosis outbreaks occurring in Northern Italy in 1995-1999. Forty-six out of 61 strains (75.4%) resulted susceptible to both isoniazid and rifampin. Thirteen strains (21.3%) were resistant to isoniazid only. No strains showed resistance to rifampin only. Two strains (3.3%) resulted resistant to both drugs, showing antituberculous multidrug-resistance. Given the compulsory eradication program of bovine tuberculosis by elimination of infected animals and the ban on antituberculous drug treatments in animals, detection of resistant M. bovis strains appears of great interest.

Animals↗

Isolation of Bartonella henselae from domestic cats in an Italian urban area.

Bartonella henselae is the causative agent of Cat Scratch Disease (CSD) in humans. Cat is considered the reservoir of the bacterium. Identification of bacteriemic cats is the basic tool in the prophylaxis of CSD. Blood samples were collected between January 1999-December 2000 from 248 domestic cats living in an urban area (Reggio Emilia) in Northern Italy and tested for Bartonella henselae bacteriemia. Cultural and PCR methods were used. PCR was used directly on cat blood as well as to identify the Bartonella strain growth in culture. 24 (9.7 %) cats were found bacteriemic, most of which aged <1 year. A higher sensitivity was demonstrated by cultural method compared with PCR.

Animals↗

Association between Chlamydia psittaci seropositivity and abortion in Italian dairy cows.

Although the seroprevalence of Chlamydia psittaci is widespread in Italian dairy herds, its role in inducing genital disorders has not been elucidated. We therefore set up a case-control study to compare seroprevalence to C. psittaci in an aborted-cow population and in a randomly selected control group in the province of Parma (the Po Valley of northern Italy). The true seroprevalence (45%) in aborted cows was significantly higher than that in the control group (24%) (adjusted odds ratio=2.53).

Abortion, Veterinary↗

Automatic evaluation of arterial diameter variation from vascular echographic images.

An automatic procedure for accurate arterial diameter evaluation from B-mode images obtained by diagnostic ultrasound systems is presented. It is used for measuring brachial artery dilation following reactive hyperemia induced by forearm ischemia, which is an appropriate parameter to study endothelial function in humans. B-mode images obtained from the diagnostic ultrasound system are acquired on a personal computer as grey intensity fields (pixels). A completely automatic algorithm is then applied and the artery walls are identified by two discrete sets of points. Artery diameter is evaluated by parabolic least-square approximation. The accuracy and extensive range of applicability of the diameter evaluation procedure were demonstrated both by preliminary analytic test cases and in vivo analyses. Reproducibility of the diameter estimate was assessed by in vivo measurements. The proposed procedure permits fast and accurate analysis of large amounts of data, because it requires no action by the operator. It thus represents a valuable tool for assessment of endothelium-dependent vasodilation, especially in large, multicentric clinical trials.

Adult↗

Mechanisms responsible for endothelial dysfunction induced by fasting hyperhomocystinemia in normotensive subjects and patients with essential hypertension.

OBJECTIVES: We sought to evaluate whether fasting hyperhomocystinemia reduces endothelial function by oxidative stress in normotensive subjects and hypertensive patients. BACKGROUND: Subjects with hyperhomocystinemia have endothelial dysfunction. METHODS: In 23 normotensive subjects and 28 hypertensive patients, classified into normohomocystinemic and hyperhomocystinemic groups according to homocysteine plasma levels (< 8.7 and >14.6 micromol/l, respectively), we studied forearm blood flow changes (strain-gauge plethysmography) induced by intrabrachial administration of acetylcholine (0.15 to 15 microg/100 ml tissue per min) or sodium nitroprusside (1 to 4 microg/100 ml per min), an endothelium-dependent and -independent vasodilator, respectively. Acetylcholine was repeated with N(G)-monomethyl-L-arginine (L-NMMA; 100 microg/100 ml per min), vitamin C (8 mg/100 ml per min) and L-NMMA plus vitamin C. RESULTS: Normotensive hyperhomocystinemic patients showed a blunted response to acetylcholine and a lower inhibiting effect of L-NMMA on acetylcholine, as compared with normohomocystinemic patients. Although vitamin C was ineffective in normohomocystinemic subjects, it increased the response to acetylcholine and restored the inhibiting effect of L-NMMA on acetylcholine in hyperhomocystinemic patients. Hypertensive hyperhomocystinemic patients showed a reduced response to acetylcholine, as compared with normohomocystinemic subjects. In both subgroups, L-NMMA failed to blunt the response to acetylcholine. The potentiating effect of vitamin C on acetylcholine was greater in hyperhomocystinemic patients than in normohomocystinemic subjects, although it restored the inhibitory effect of L-NMMA on acetylcholine-induced vasodilation to the same extent in both groups. Hyperhomocystinemia did not change the response to sodium nitroprusside. CONCLUSIONS: In normotensive subjects and hypertensive patients, hyperhomocystinemia impairs endothelium-dependent vasodilation. It could be related to oxidant activity.

Acetylcholine↗

Soluble E-selectin in essential hypertension: a correlate of vascular structural changes.

BACKGROUND: Increased expression of the endothelial leukocyte adhesion molecule E-selectin is implicated in vascular disease and may accompany the development of hypertension. We evaluated plasma soluble (s) E-selectin to assess its relationship with endothelium-dependent and endothelium-independent vasodilation in patients with hypertension. METHODS: Thirty-one previously untreated and uncomplicated essential hypertensive patients were compared with 16 normotensive controls for changes in forearm blood flow (by strain-gauge plethysmography) in response to brachial artery infusion of the endothelium-dependent vasodilator acetylcholine, and of the endothelium-independent vasodilator sodium nitroprusside. As an index of structural changes, minimal forearm vascular resistances were calculated as the ratio between maximal vasodilation after 13 min of ischemia and mean blood pressure. RESULTS: Responses to acetylcholine were significantly lower and minimal forearm vascular resistances higher in hypertensives versus controls, whereas responses to nitroprusside were comparable. Baseline sE-selectin concentrations were (mean +/- SEM) 37.4 +/- 1.8 ng/mL in hypertensives and 27.8 +/- 0.7 ng/mL in normotensives (P < .001). In essential hypertensive patients, a significant (P < .01) correlation with the response to nitroprusside (r = -0.47) was found, but not with the response to acetylcholine or minimal forearm vascular resistances. sE-selectin was also positively correlated with age and LDL cholesterol. At multivariate analysis, sE-selectin remained significantly correlated with nitroprusside responses and LDL cholesterol. CONCLUSIONS: In patients with essential hypertension, plasma levels of sE-selectin are higher than in normotensive controls and mostly related to structural vascular changes.

Acetylcholine↗

Role of endothelin in the control of peripheral vascular tone in human hypertension.

Endothelins are potent 21 amino acid vasoconstrictor isopeptides produced in different vascular tissues, including vascular endothelium. Endothelin-1 is the main endothelin generated by the endothelium and probably the most important in the cardiovascular system. Endothelin-1 acts through specific receptors termed ET(A), represented only on smooth muscle cells and having the function of growth promotion and mediating contractions, and ET(B), located both on smooth muscle cells, where they evoke contractions, and on endothelial cells, inducing relaxation by production of the endothelium-derived relaxing factor nitric oxide. In physiological conditions endothelin-1 administration causes vasodilation and vasoconstriction at low and high concentrations, respectively. However, administration of mixed ET(A)/(B) receptor antagonists causes slight or absent vasodilation, indicating that the direct vasoconstrictor effect of the peptide is probably masked by ET(B)-induced NO-dependent vasodilation. In essential hypertensive patients, the activity of exogenous endothelin-1 is either increased, similar or decreased as compared to normotensive subjects, depending on which vascular district or scheme of administration is considered. But although available evidence does not indicate increased endothelin-1 plasma levels in patients with essential hypertension, simultaneous antagonism of ET(A)/(B) receptors causes a greater degree of vasodilation in hypertensives than in normotensive subjects. Moreover administration of a selective ET(B) receptor antagonist causes vasoconstriction in normotensive subjects and vasodilation in essential hypertensive patients. Finally, the vasodilating effect of a mixed ET(A)/(B) receptor antagonist is inversely related to NO availability. Taken together these findings suggest that essential hypertension is characterized by increased endothelin-1 vasoconstrictor tone. This alteration seems to be dependent on decreased endothelial ET(B)-mediated NO production attributable to impaired NO availability. In such conditions endothelial ET(B)-induced vasodilation no longer compensates for the direct classical endothelin vasoconstrictor effect mediated by smooth muscle cell ET(A) and ET(B) receptors. Therefore endothelin-1 could potentially be involved in the pathogenesis of essential hypertension or of its complications, and blockade of this system is a fascinating new target for therapeutic intervention in this disease.

Endothelin Receptor Antagonists↗