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Biomedical subjects

F Paganelli

Publications and source records attributed to F Paganelli.

At least 19 recordsLinked to original sources
PubMed2007

The lakes of Titan.

The surface of Saturn's haze-shrouded moon Titan has long been proposed to have oceans or lakes, on the basis of the stability of liquid methane at the surface. Initial visible and radar imaging failed to find any evidence of an ocean, although abundant evidence was found that flowing liquids have existed on the surface. Here we provide definitive evidence for the presence of lakes on the surface of Titan, obtained during the Cassini Radar flyby of Titan on 22 July 2006 (T16). The radar imaging polewards of 70 degrees north shows more than 75 circular to irregular radar-dark patches, in a region where liquid methane and ethane are expected to be abundant and stable on the surface. The radar-dark patches are interpreted as lakes on the basis of their very low radar reflectivity and morphological similarities to lakes, including associated channels and location in topographic depressions. Some of the lakes do not completely fill the depressions in which they lie, and apparently dry depressions are present. We interpret this to indicate that lakes are present in a number of states, including partly dry and liquid-filled. These northern-hemisphere lakes constitute the strongest evidence yet that a condensable-liquid hydrological cycle is active in Titan's surface and atmosphere, in which the lakes are filled through rainfall and/or intersection with the subsurface 'liquid methane' table.

Journal Article↗
PubMed2006

Titan Radar Mapper observations from Cassini's T3 fly-by.

Cassini's Titan Radar Mapper imaged the surface of Saturn's moon Titan on its February 2005 fly-by (denoted T3), collecting high-resolution synthetic-aperture radar and larger-scale radiometry and scatterometry data. These data provide the first definitive identification of impact craters on the surface of Titan, networks of fluvial channels and surficial dark streaks that may be longitudinal dunes. Here we describe this great diversity of landforms. We conclude that much of the surface thus far imaged by radar of the haze-shrouded Titan is very young, with persistent geologic activity.

Journal Article↗
PubMed2006

The sand seas of Titan: Cassini RADAR observations of longitudinal dunes.

The most recent Cassini RADAR images of Titan show widespread regions (up to 1500 kilometers by 200 kilometers) of near-parallel radar-dark linear features that appear to be seas of longitudinal dunes similar to those seen in the Namib desert on Earth. The Ku-band (2.17-centimeter wavelength) images show approximately 100-meter ridges consistent with duneforms and reveal flow interactions with underlying hills. The distribution and orientation of the dunes support a model of fluctuating surface winds of approximately 0.5 meter per second resulting from the combination of an eastward flow with a variable tidal wind. The existence of dunes also requires geological processes that create sand-sized (100- to 300-micrometer) particulates and a lack of persistent equatorial surface liquids to act as sand traps.

Extraterrestrial Environment↗
PubMed2006

Effect of long-term atorvastatin treatment on the electrophysiological and mechanical functions of muscle.

OBJECTIVE: To study alterations in muscle function combining physiological, electrophysiological and metabolic measurements in patients receiving a statin at various dosages during long-term therapy. MATERIAL: A 3-month (D0, D30 and D90) longitudinal physiological and electrophysiological muscle study was performed in 26 patients receiving 10, 40 or 80 mg/day atorvastatin. METHOD: All subjects performed maximal (MVC) and submaximal (60% MVC) isometric thumb adduction, handgrip and knee extension exercises during the recording of surface electromyograms (EMG) of the adductor pollicis (AP), flexor digitorum (FD) and vastus lateralis (VL). The compound muscle potential (M-wave) evoked by direct muscle stimulation was measured at rest and after 60% MVCs and the EMG power spectrum was analyzed during sustained effort. Blood was sampled from an antecubital vein for measurements of pH, lactate and potassium levels after thumb adduction and handgrip exercises. The measurements were repeated on Day 0 (D0), D30 and D90. RESULTS: Atorvastatin did not affect the MVC and endurance time to fatigue. Post-exercise M-wave alterations in the AP began at D30 with the 80 mg/day treatment and there was a reduced or suppressed leftward shift in the EMG power spectrum in the AP and VL with all 3 dosages. In the AP, the EMG changes appeared earlier (D30) with 80 mg/day whereas they only occurred at D90 on the lower dosages. Atorvastatin had no effect on the maximal postexercise variations in pHv and lactate but it significantly reduced the maximal increase in plasma potassium concentration after thumb adduction and handgrip exercise, the effects being only present at D90 on 10 mg/day but occurring as early as D30 with higher dosages. CONCLUSION: A 3-month atorvastatin treatment did not affect the maximal performance of skeletal muscle during voluntary efforts but EMG analysis revealed a reduced muscle excitability and an attenuated adaptation to fatigue. These effects prevailed in muscles containing the largest proportion of slow-oxidative fibers and were associated with a reduced outward flow of potassium.

Anticholesteremic Agents↗
PubMed2006

The imbalance between circulating endothelial cells and progenitors in cardiovascular diseases: a mirror of disrupted endothelial integrity.

The disruption of endothelial integrity is at the crossroads of the initiation and progression of multiple cardiovascular diseases pathophysiology. During these last years, it has been evidenced that endothelium is a highly dynamic tissue in equilibrium with a circulating compartment composed of various sub-populations offering important opportunities for a non-invasive exploration. Among these, circulating endothelial cells (CEC) are mature cells detached from injured vessels. Rarely found in blood in the health, CEC number is raised in a wide variety of pathological conditions associated with profound vascular insult. An additional population are the endothelial progenitor cells derived from bone marrow and characterised by their ability to participate in endothelial repair. Reduced number and impaired function of EPC have been related to situations with increased cardiovascular risk or to clinical atherosclerotic diseases. This review will focus on present data concerning CEC and endothelial cells and progenitors (PEC) in the setting of cardiovascular diseases. Particular emphasis will be given on the clinical value of these endothelial biomarkers to monitor endothelial homeostasis depending on the balance between endothelial injury and repair.

Biomarkers↗
PubMed2005

Covered stent for closure of symptomatic plexus-like coronary fistula.

Coronary to pulmonary artery fistula are the most frequent congenital anomalies of the coronary arteries. When they are symptomatic they have to be treated in order to prevent complications such as sudden death or myocardial infarction. Surgery is the gold standard for their closure. However an increasing number of reports have shown that interventional cardiology could be a safe and efficient alternative. Plexus-like fistula are composed of multiples and tortuous branches that make them difficult to treat. We report the use of polytetrafluoroethylene-covered (PTFE) stent to cure a plexus-like coronary to pulmonary artery fistula, without associated atherosclerosis, responsible for myocardial ischemia.

Aged↗
PubMed2005

Cassini radar views the surface of Titan.

The Cassini Titan Radar Mapper imaged about 1% of Titan's surface at a resolution of approximately 0.5 kilometer, and larger areas of the globe in lower resolution modes. The images reveal a complex surface, with areas of low relief and a variety of geologic features suggestive of dome-like volcanic constructs, flows, and sinuous channels. The surface appears to be young, with few impact craters. Scattering and dielectric properties are consistent with porous ice or organics. Dark patches in the radar images show high brightness temperatures and high emissivity and are consistent with frozen hydrocarbons.

Atmosphere↗
PubMed2005

Lipid-altering efficacy of switching from atorvastatin 10 mg/day to ezetimibe/simvastatin 10/20 mg/day compared to doubling the dose of atorvastatin in hypercholesterolaemic patients with atherosclerosis or coronary heart disease.

This randomised, double-blind study evaluated the efficacy and safety of ezetimibe/simvastatin (EZE/SIMVA) 10/20 mg tablet compared to doubling the atorvastatin (ATV) dose in hypercholesterolaemic patients with atherosclerotic or coronary heart disease (CHD). The study group included 435 male and female CHD patients (aged >or=18 years) who had not achieved their low-density lipoprotein cholesterol (LDL-C) goal of <2.50 mmol/l while on a stable dose of ATV 10 mg for >or=6 weeks. After a 1-week diet/stabilisation period, patients with LDL-C >or=2.50 mmol/l and <or=4.20 mmol/l were randomised (1:1) to EZE/SIMVA 10/20 mg/day (n = 221) or ATV 20 mg/day (n = 214) for 6 weeks. The primary efficacy objective was to determine the per cent reduction from baseline in LDL-C at week 6. EZE/SIMVA 10/20 mg produced significantly greater mean per cent changes from baseline in LDL-C compared with ATV 20 mg (-32.8 vs. -20.3%; p </= 0.001). A significantly greater proportion of patients achieved an LDL-C goal <2.50 mmol/l with EZE/SIMVA than ATV (77.9 vs. 51.9%; p <or= 0.001). Significant improvements in total cholesterol (-20.3 vs. -13.0%), non-high-density lipoprotein cholesterol (non-HDL-C) (-27.9 vs. -17.0%), apolipoprotein B (-23.4 vs. -14.7%) and HDL-C (1.8 vs. -0.4%) were observed after switching to EZE/SIMVA 10/20 mg for 6 weeks (p < 0.05 for all parameters). EZE/SIMVA 10/20 mg was generally well tolerated, with an overall safety profile similar to that of ATV 20 mg. EZE/SIMVA 10/20 mg produced superior lipid-altering efficacy by dual inhibition of cholesterol synthesis and intestinal absorption compared with doubling the dose of ATV from 10 to 20 mg.

Adult↗
PubMed2004

The SF-36 instrument for the follow-up of health-related quality-of-life assessment of patients undergoing home parenteral nutrition for benign disease.

INTRODUCTION: The non-disease-specific SF-36 instrument was applied to detect changes in quality of life among patients at a single center who were receiving home parenteral nutrition (HPN) for intestinal failure. METHODS: All HPN patients completed the questionnaire during routine visits. The SF-36 examines eight domains (scores: 0% to 100%): physical functioning (PF), role-functioning physical (RP), body pain (BP), general health (GH), vitality (VT), social functioning (SF), as well as role-functioning emotional (RE) and mental health (MH). Patient responses were standardized for the sex- and age-matched group scores of the healthy population by calculating the Z-score: (healthy population mean score - patient raw score)/healthy population standard deviation (reduced value: Z-score < -1). A difference in a domain score was considered significant in the individual patient if it was greater than the 90% confidence interval for healthy subjects and if it produced a change in Z-score category. General, sociodemographic, underlying disease and HPN-related factors were collected. RESULTS: For 31 enrolled adult patients, the baseline mean Z-score was reduced in five domains: PF, RP, BP, GH and SF. Twenty patients underwent a second SF-36 assessment 10 +/- 2 months later: the HRQOL worsened in eight and improved in 10 (no. worsened domains > no. improved or vice versa). The worsened subgroup showed a decrease in body mass index (P =.104), an increase in the number of HPN infusions per week (P =.065), and a greater incidence of intestinal motility disorders (P =.161), of liquid oral diet (P =.027), and of nycturia (P =.028). CONCLUSIONS: The SF-36 instrument reflecting the generic HRQOL assessment may be a suitable tool for patients on HPN.

Adolescent↗
PubMed2004

Italian guidelines for intestinal transplantation: potential candidates among the adult patients managed by a medical referral center for chronic intestinal failure.

In 2002, the Italian guidelines for eligibility of patients for intestinal transplantation (ITx) were defined as: life-threatening complications of home parenteral nutrition (HPN), lack of venous access for HPN, locally invasive tumors of the abdomen, Chronic intestinal failure (CIF) with a high risk of mortality, primary disease-related poor quality of life (QoL) despite optimal HPN. Our aim was to identify potential candidates for ITx according to these national guidelines among patients managed by a medical referral center for CIF. Records of patients who received HPN were reviewed. CIF was considered reversible or irreversible (energy by HPN <50% or >50% basal energy expenditure). Patients with irreversible CIF were considered eligible for ITx in the absence of a contraindication, as are used for solid organs Tx. From 1986 to 2003 among 64 patients who met the entry criteria 23 showed reversible and 41 irreversible, CIF. Twenty-one patients with irreversible CIF had an indication for ITx, but eight had also contraindications; thus 13 were eligible, including intestinal pseudo-obstruction (n = 6), mesenteric ischemia (n = 3), Crohn's (n = 2), radiation enteritis (n = 1), and desmoid (n = 1). Indications for ITx included HPN liver failure (n = 2), lack of venous access (n = 2), CIF with high risk of mortality (n = 3), very poor QoL (n = 6 including 5 with pseudo-obstruction). According to the Italian guidelines for ITx, 31% of patients with irreversible CIF managed by a medical referral center were eligible for ITx. Primary disease-related poor QoL was the indication in half of them. Studies on the QoL after ITx are required to allow patients to make an educated decision.

Adult↗
PubMed2004

[Cardiovascular symptoms and risks of subclinical dysthyroidism].

PURPOSE: To clarify the importance of cardiovascular symptoms and risks in subclinical dysthyroidism in order to define the best way of treatment and follow-up. CURRENT KNOWLEDGE AND KEY POINTS: Subclinical dysthyroidism is defined by abnormal circulating TSH values in face and normal free thyroid hormones levels, in asymptomatic individuals. If the cardiovascular effects of overt hyperthyroidism are well documented, the relation between subclinical dysthyroidism and the heart is not well established. Subclinical hyperthyroidism may be caused by the same thyroid disorders that results in overt hyperthyroidism, but the most common cause is excessive dosage in levothyroxine. The most frequent cardias complication of subclinical hyperthyroidism is atrial fibrillation. Recently minimal alterations of myocardial function have also been described. In most patients, one tries to return to euthyroidism in order to prevent cardiovascular complications. Subclinical hypothyroidism is 3 to 10 times more frequent, especially in women after 60 years. Subtle modifications of cardiac function and lipid metabolism and an increased risk of atherosclerosis have been described in this condition. There is still debate about the decision to treat or not to treat these patients. FUTURE PROSPECTS AND PROJECTS: Until now, treatment of subclinical dysthyroidism is mainly based upon experiences and convictions to physicians. Prospective studies are necessary to assess the true benefits and risks of either early treatment or therapeutic abstention with regular clinical and biological follow up. In such studies, patients should be separated according to age and the nature (endogenous or exogenous) of dysthyroidism.

Cardiovascular Diseases↗
PubMed2004

Protective effect of a low K+ cardioplegic solution on myocardial Na,K-ATPase activity.

Long duration ischemia in hypothermic conditions followed by reperfusion alters membrane transport function and in particular Na,K-ATPase. We compared the protective effect of two well-described cardioplegic solutions on cardiac Na,K-ATPase activity during reperfusion after hypothermic ischemia. Isolated perfused rat hearts (n = 10) were arrested with CRMBM or UW cardioplegic solutions and submitted to 12 hr of ischemia at 4 degrees C in the same solution followed by 60 min of reperfusion. Functional recovery and Na,K-ATPase activity were measured at the end of reperfusion and compared with control hearts and hearts submitted to severe ischemia (30 min at 37 degrees C) followed by reflow. Na,K-ATPase activity was not altered after 12 hr of ischemia and 1 hr reflow when the CRMBM solution was used for preservation (55 +/- 2 micromolPi/mg prot/hr) compared to control (53 +/- 2 micromol Pi/mg prot/hr) while it was significantly altered with UW solution (44 +/- 2 micromol Pi/mg prot/hr, p < 0.05 vs control and CRMBM). Better preservation of Na,K-ATPase activity with the CRMBM solution was associated with higher functional recovery compared to UW as represented by the recovery of RPP, 52 +/- 12% vs 8 +/- 5%, p < 0.05 and coronary flow (70 +/- 2% vs 50 +/- 8%, p < 0.05). The enhanced protection provided by CRMBM compared to UW may be related to its lower K+ content.

Adenosine↗
PubMed2004

Dose dependent accretion of docosahexaenoic acid (DHA) in cardiac membranes of rats fed egg yolk powder enriched in DHA.

We tested the hypothesis that enrichment of the diet with docosahexaenoic acid (DHA) enriched egg yolk powder could modify specifically the (n-3) fatty acids content of rat plasma, red blood cells and heart membranes. Dose-dependent effect of DHA was studied in rats supplemented during 4 weeks. Three groups of adult male rats, DHA10, DHA35 and DHA60 (n = 5 each), had their diet supplemented with 10 mg, 35 mg or 60 mg DHA/kg body weight/day, respectively. Fatty acid composition of membranes and plasma lipids were determined. A significant dose-dependent increase in DHA was observed in all three types of samples. Arachidonic acid (AA) levels did not change in heart and red blood cell membranes whereas it increased significantly in plasma with the DHA35 diet. These results contrast with that previously reported for fish oil supplementation where a decrease in AA levels was reported. Hence, DHA enriched egg yolk supplementation leads to a specific accretion of DHA without competition on AA status.

Animals↗
PubMed2003

Hypothalamo-pituitary-adrenal axis in acute myocardial infarction treated by percutaneous transluminal coronary angioplasty: effect of time of presentation.

Acute myocardial infarction (AMI) is associated with a stimulation of cortisol which lasts 24 hours in patients treated by thrombolysis. Percutaneous transluminal coronary angioplasty (PTCA) is an alternative treatment for AMI which reduces the length of myocardial ischemia. Our objective was the determination of the amplitude and duration of cortisol and other hormones of the hypothalamo-pituitary-adrenal (HPA) axis release in patients undergoing PTCA. These responses were also analyzed in relation with the time of onset of AMI. The effect of coronarography with or without angioplasty in patients without AMI was also studied. Plasma ACTH, cortisol, corticotropin-releasing hormone and arginine vasopressin levels were determined during the first 48 hours in 20 patients with first AMI, treated by PTCA and in 10 patients without AMI undergoing coronarography (and angioplasty in five of them). A strong stimulation of the HPA axis was observed in AMI patients, but the duration of cortisol secretion was significantly reduced (less than 8 hours) as compared with previous studies in patients treated with thrombolysis. A clear-cut ACTH-cortisol dissociation was also observed after the third hour. ACTH and cortisol stimulation was higher in patients admitted between 04:00 h and 16:00 h than in patients admitted between 16:00 h and 04:00 h In patients without AMI, coronarography induced a moderate, but significant short-lasting ACTH and cortisol stimulation. In conclusion, our data suggest that the degree of stimulation of the HPA axis may depend upon the type of treatment and the circadian rhythm of this axis.

Adrenocorticotropic Hormone↗
PubMed2003

Safety and efficacy of home parenteral nutrition for chronic intestinal failure: a 16-year experience at a single centre.

BACKGROUND: Comparisons between safety and efficacy of home parenteral nutrition and of intestinal transplantation for treatment of chronic intestinal failure derived from observational studies. AIMS: To present the 16-year experience of home parenteral nutrition by the Chronic Intestinal Failure Centre of Bologna University. PATIENTS: A total of 40 adult patients were enrolled between 1986 and 2001. METHODS: Safety indices: survival and cause of death, catheter-related bloodstream infection, deep vein thrombosis, liver disease. Efficacy indices: nutritional and rehabilitation status, quality of life (SF36 instrument), re-hospitalisation rate. STATISTICS: Kaplan-Maier analysis and Cox model for survival probability and risk factors; logistic regression for catheter-related bloodstream infection risk factors. RESULTS: Survival rates at 1, 3 and 5 years were 97, 82 and 67% respectively. Survival was higher in patients < or = 40 years. One death was home parenteral nutrition-related. Incidence of catheter-related bloodstream infection: 0.30/year home parenteral nutrition, was lower in patients treated by a specialized nursing protocol. Incidence of deep vein thrombosis was 0.05/year home parenteral nutrition. Hepatosteatosis occurred in 55%. Body weight remained stable or increased in 80%. Rehabilitation was total or partial in 74%. Re-hospitalisation rate was 0.70/year home parenteral nutrition. Quality of life scored significantly lower than in healthy populations in six out of eight domains. CONCLUSIONS: Home parenteral nutrition is a safe and efficacious therapy for chronic intestinal failure. Survival compares favourably with survival after intestinal transplantation.

Adolescent↗