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Biomedical subjects

A Luca

Publications and source records attributed to A Luca.

At least 19 recordsLinked to original sources
PubMed2006

In situ split liver transplantation for adult and pediatric recipients: an answer to organ shortage.

BACKGROUND: We report our initial experience with in situ split liver transplantation (SLT) for adult and pediatric patients. PATIENTS AND METHODS: From June 2003 to August 2005, 177 liver transplantations in 165 patients, 133 adults (81%) and 32 children (19%), were performed at our institution. Over this period, 45 liver transplantations (25%) were performed with an in situ split liver technique in 44 patients: 17 (39%) were adults and 27 (61%) children. All of the adult split liver recipients were transplanted with an extended right graft (ERG; segments I + IV-VIII), while pediatric recipients received in 23 cases a left lateral segment (LLS; segments II-III) and in 4 cases an ERG from a pediatric donor. The 45 split liver grafts (21 ERGs and 24 LLSs) were generated from 35 donors. In 10 cases we used both grafts generated with an in situ split procedure to transplant our patients, while in 25 cases the procurement procedure was performed in collaboration with other transplant centers. RESULTS: After a median follow-up of 9 months (range, 1-27 months), the overall patient survival rate was 88% for adult patients and 82% for pediatric patients. Graft survivals were 88% and 79%, respectively. Two adult patients (12%) died from sepsis in the early postoperative period. Five children (18%) died after their transplantations. Only one pediatric recipient (2%) of primary SLT underwent retransplantation. Vascular complications were absent in adult recipients, whereas 4 arterial (14%) and 4 venous (14%) complications developed in the pediatric population. The incidence of biliary complications was 23% in adult and 18% in pediatric recipients. CONCLUSIONS: The use of in situ SLT for adult and pediatric populations allowed us to expand the cadaveric donor pool, significantly eliminating pediatric waiting list mortality without penalizing the adult population.

Adult↗
PubMed2006

Efficacy of interventional radiology procedures for the treatment of early ureteral complications after kidney transplantation.

UNLABELLED: Ureteral stricture and ureteral leakage are the most common early urological complications after kidney transplantation causing decreased urine output and increased serum creatinine and blood urea nitrogen. We report our experience with internal-external ureteral stent placement and ureteroplasty. MATERIALS AND METHODS: From August 1999 to January 2005, we treated nine patients presenting with stricture or leak. After an anterograde pyelogram, an internal-external nephrostomy catheter was inserted in all patients; in four patients we also performed ureteroplasty. RESULTS: The stricture and leak appeared from 12 to 93 days after kidney transplantation (mean = 39 +/- 29 days). After a mean of 80 +/- 43 days (range 25-141 days), the stent was successfully removed in seven patients (77%); no patient had a recurrence. The success was confirmed by a decline in serum creatinine (from 3.7 +/- 1.4 to 1.6 +/- 0.7 mg/dL) and blood urea nitrogen (from 54 +/- 24 to 28 +/- 7 mg/dL) with resolution of hydronephrosis on sonography. No procedure-related complications were observed. Surgical correction was necessary in two patients due to the persistence of a stricture. At long-term follow-up (50 +/- 17 months), seven kidneys were still functioning and two had failed due to chronic rejection. CONCLUSION: Nephrostomy catheter placement and ureteroplasty are safe, effective alternatives to surgery to treat early ureteral complications after kidney transplantation. Interventional radiology procedures reducing the morbidity and the likelihood of loss of graft function may improve graft and patient survival.

Catheters, Indwelling↗
PubMed2002

Results obtained in the metrological certification of a commercially available radionuclide calibrator.

The paper presents the results obtained at IFIN-HH during a metrological certification of the commercially available radionuclide calibrator, the CURIEMENTOR2. Its performance was tested for the radionuclides: 57Co, 99mTc, 131I and 137Cs. The calibration factors determined by the manufacturer and those obtained at IFIN-HH differed by less than 3.5%. New calibration factors were determined for 60Co and 188Re, which have, until now, not been distributed by the manufacturer to the users. Furthermore, the linearity of instrument response and the dependence of measuring geometry were checked and found in accordance with the international accepted standards and legal requirements.

Calibration↗
PubMed2002

Lactate levels in open interstitial thermal ablation for liver tumors.

Intraoperative radio frequency interstitial thermal ablation (RITA) may result in a reduction of the functional hepatic reserve. To assess this further, we evaluated perioperative lactate levels as a measure of hepatic dysfunction. Sixteen patients scheduled for open RITA (O-RITA) were enrolled in the study. Arterial lactate levels (mmol/L) were measured prior to tumor needle insertion (T0), after O-RITA completion (T1), after wound closure (T2) and 24 hrs after surgery (T3). Correlation between hemodynamic parameters including MAP, and CVP, at T0, T1, T2, T3 and the perioperative rate of lactate production were also analyzed. Total bilirubin, transaminases and international normalized ratio for prothrombin activity (INR) were measured preoperatively and postoperative at day 1, 2, 3 and 7. Data are expressed as mean +/- SD and analyzed with ANOVA. Additionally, the Duncan post hoc test was used for multiple comparisons of the differences in mean values. A p-value <0.05 was considered significant. Lactate levels did not increase significantly at time points specified above (P = NS). Similarly, hemodynamic parameters analyzed did not show any significant change at the different time points (P = NS). Total bilirubin and INR did not demonstrate statistically significant changes at the aforementioned time points. Serum transaminases peaked during the immediate postoperative period and normalized to preoperative values by one-week post surgery. These results demonstrate that O-RITA does not induce hyperlactatemia and does not reduce the functional residual liver parenchyma.

Aged↗
PubMed2001

The hepatic artery in liver transplantation and surgery: vascular anomalies in 701 cases.

The purpose of this study is to report the variations in hepatic arterial supply of a mixed population of organ donors in which the anatomy was individually examined during the bench surgery, and patients who underwent a selective angiogram of the celiac axis and superior mesenteric artery. We reviewed the donor forms and/or angiograms of 701 patients. The donor forms were completed personally by one of the authors, while all the radiology images were obtained through studies performed by one single radiologist. The arterial anatomy was anomalous in 296 out of 701 cases with an overall incidence of hepatic artery anomalies of 42.22%. In this paper we describe previously unreported arterial anomalies of the hepatic artery, collecting the second largest series of hepatic artery anatomical variations of the English literature. This anatomical update can be useful for transplant and general surgeons, as well as vascular radiologists.

Female↗
PubMed2001

Observation interval for evaluating the costs of surgical interventions for older women with a new diagnosis of breast cancer.

OBJECTIVE: To estimate the episodic costs of surgical treatments for breast cancer. METHODS: The surgical treatment period as the 6 weeks following diagnosis is defined. Using a sample of 205 women aged 65 and older and their Medicare claim files, the cost of treatment is estimated and the progression from first to subsequent surgical procedures during the 6-week interval is demonstrated with a decision tree. Two equations are then estimated: the probability of mastectomy versus breast conserving surgery (BCS) as first surgery using Probit regression and the log of total charges using a generalized linear regression model. RESULTS: It was found that only stage predicts the probability of mastectomy versus BCS and that 54% of women receiving BCS undergo a second surgery. Once all treatments in the initial surgical period are accounted, the difference between the adjusted cost of mastectomy alone and BCS followed by a second surgery was not statistically significant. Only a successful first BCS is statistically significantly (P <0.05) less costly than a mastectomy alone ($4,955 vs. $9,049). CONCLUSIONS: By defining a 6-week surgical treatment episode it is shown that BCS followed by subsequent surgeries is the more costly option for initial treatment. Given the high prevalence of second surgeries, previous work may have underestimated the costs of surgical interventions for breast cancer.

Aged↗
PubMed2000

Low level gamma spectrometry by beta-gamma coincidence

A beta-gamma coincidence system consisting of a 2pi plastic beta detector and a Ge(Li) detector, is described. Such a system allows for a drastic reduction of background (approximately 70 times) as well as of Minimum Detectable Activity (approximately 7 times). An integral background (50-1500 keV) of less than 0.1 cps is obtained. The difficulty of the method, otherwise simple and inexpensive, is the precise determination of beta detector efficiency.

Journal Article↗
PubMed2000

Emission probabilities of the main gamma-rays of 237Np in equilibrium with 233Pa

Due to the needs in environment monitoring and nuclear waste survey, there has been increasing interest over recent years for measuring the activity of 237Np. Thus, the EUROMET project No. 416 has been proposed by NPL, in order to improve as well as possible the knowledge of the decay scheme of this radionuclide. In order to achieve this objective, the emission probabilities of the main gamma-rays following the decay of 237Np in equilibrium with its daughter 233Pa, have been precisely measured, using calibrated Ge-HP detectors and sources for which the activity has been determined from absolute measurement. The obtained results, the main instrumentation characteristics, details of the experimental procedure, are presented and discussed in this paper.

Journal Article↗
PubMed2000

The standardization of a 204Tl solution

Two methods were used for the standardization of the 204Tl solution received in the framework of the 1997 BIPM comparison. The first method, 4pi liquid scintillation (LS), consisted of the extrapolation of the 4pi counting rate to the zero discrimination level. A home-made, single channel instrument and a commercial Packard INSTA-GEL scintillator were used. The radioactivity concentration on the reference date 1 April 1997 was 63.1+/-1.3 kBq g(-1). The second method was the efficiency tracer technique, using a 60Co standard solution; the radioactivity concentration was calculated as the mean of several extrapolated values of the curve NbetaTl-204 = N0Tl-204f(1 - epsilon(betaCo-60)). The preliminary reported value was 62.8+/-0.8 kBq g(-1); the revised value is 61.8+/-1.2 kBq g(-1), in good agreement with other 4pi (p.c.) tracer results in the comparison. Some remarks are made regarding our measurements and the comparison results.

Journal Article↗
PubMed2000

Standardization of 169Yb by the 4pibeta-gamma method

169Yb was standardized in the framework of an EUROMET international comparison. Two solutions, with approximately activity concentrations of 16 MBq g(-1) and 1.6 MBq g(-1) were distributed to the participants by BNM-LPRI-(France). In the Radionuclide Metrology Laboratory of INFIN-HH, the weak solution was standardized using a coincidence method, applying the 'beta-efficiency extrapolation' variant. A simple 4pi beta-gamma coincidence equipment was used. Due to the presence of a metastable state with a half-life of 0.66 micros in the decay scheme of 169Tm, a resolution time of 5.1 micros was chosen for the coincidence module. A gamma threshold of 150 keV was used. A second degree extrapolation graph was used, providing an activity concentration value of 1.18 MBq g(-1) at 15 November 1997, 12 h UT. The combined uncertainty was 0.9%. Using the dilution factor provided by BNM-LPRI, the corresponding activity concentration for the strong solution is 11.989 MBq g(-1) (uA = 0.110MBq g(-1); 0.92%).

Journal Article↗
PubMed1999

Effects of end-to-side portacaval shunt and distal splenorenal shunt on systemic and pulmonary haemodynamics in patients with cirrhosis.

BACKGROUND: Patients with cirrhosis exhibit splanchnic, peripheral and pulmonary vasodilation, which are thought to play a role in increasing portal pressure, promoting sodium retention and determining arterial hypoxaemia. The present study investigated whether these abnormalities are influenced by portal hypertension or by portal systemic shunting. METHODS: Sixty-one patients with cirrhosis who had haemodynamic measurements before and after end-to-side portacaval shunt (n = 30) or distal splenorenal shunt (n = 31) were evaluated. RESULTS: End-to-side portacaval shunts were more effective than distal splenorenal shunts in decompressing the portal system (portocaval pressure gradient 3.2 +/- 2.5 vs splenocaval gradient 6.5 +/- 3.2 mmHg, P < 0.0001), because of a greater shunt blood flow (33 +/- 12 vs 21 +/- 12 mL/min per kg, P < 0.005). Azygos blood flow and hepatic blood flow decreased significantly after both surgical shunts. However, end-to-side portacaval shunts caused a greater decrease in peripheral resistance than distal splenorenal shunts (-23 +/- 18 vs -11+/- 27%, P < 0.05). Mean arterial pressure and pulmonary vascular resistance were significantly reduced after an end-to-side portacaval shunt (-7 +/- 10%, P < 0.001 and -14 +/- 33%, P < 0.004, respectively), but not after splenorenal shunt. CONCLUSIONS: These results show that end-to-side portacaval shunts, despite normalizing portal pressure, worsen the peripheral and pulmonary vasodilatation. The splenorenal shunt that maintained a higher portal pressure, caused less peripheral vasodilatation and did not enhance pulmonary vasodilatation. These findings suggest that portal systemic shunting is more important than increased portal pressure in determining peripheral vasodilatation in cirrhosis.

Adult↗
PubMed1999

TIPS for prevention of recurrent bleeding in patients with cirrhosis: meta-analysis of randomized clinical trials.

PURPOSE: To compare the effects of transjugular intrahepatic portosystemic shunt (TIPS) creation with those of endoscopic treatment with or without propranolol administration (i.e, conventional treatment) on recurrent bleeding, encephalopathy, and mortality by using meta-analysis of 11 published randomized clinical trials. MATERIALS AND METHODS: Data from 11 relevant studies were retrieved by means of computerized and manual search. The combinability of the studies was assessed in terms of clinical and statistical criteria. Data were extracted on the basis of the intention-to-treat principle, and treatment effects were measured as risk differences between TIPS creation and conventional treatment. Pooled estimates were computed according to a random-effects model. RESULTS: A total of 750 patients were included in 11 trials. No significant heterogeneity was found for any of the outcomes. Pooled risk differences were recurrent bleeding, -31% (95% CI, -39%, -23%); encephalopathy, +16% (95% CI, +10%, +22%); death due to all causes, +2% (95% CI, -4%, +9%); and death due to bleeding, -5% (95% CI, -11%, +6%). Clinically important complications occurred in 22% of patients and were associated with both treatments. TIPS dysfunction occurred in 55% of patients. CONCLUSION: TIPS creation markedly reduces risk of rebleeding but increases risk of encephalopathy without affecting survival. Therefore, TIPS creation may not be the best first-choice therapy for prevention of recurrent variceal bleeding. Criteria for selection of candidates for TIPS creation should be assessed in future prospective studies.

Esophageal and Gastric Varices↗
PubMed1998

[Focal liver lesions. A comparison between magnetic resonance under base conditions and after a superparamagentic contrast medium].

INTRODUCTION: Superparamagnetic iron oxide (Spio) is a negative contrast material which is phagocytosed by reticuloendothelial cells. It significantly decreases the signal intensity of the organs where it is taken up selectively, especially on T2-weighted images. According to previous reports, it improves the visualization of focal liver lesions with(out) a low content of Kupffer's cells. We investigated the yield of Spio-enhanced MRI in the detection and characterization of focal liver lesions. MATERIALS AND METHODS: Eighteen patients underwent MRI before and after the administration of Spio particles. T1, PD, T2 SE and T2* GE images were acquired with a .5 T superconductive unit. The Spio dose was .075 mL/kg which was administered i.v. in 35-45 minutes' infusions. Images were acquired about 30-90 minutes after the end of administration. Scanning was repeated in one patient about 8 hours after the end of Spio administration. RESULTS: Baseline MRI showed hepatocellular carcinoma (HCC) in 10 patients, metastases in 4, 1 dysplastic lesion, 1 single and 1 multiple hemangioma, 1 focal nodular hyperplasia (FNH) and 1 intrahepatic cholangiocarcinoma. No lesion was detected in one patient. Spio-enhanced MRI detected 7 more lesions that baseline MRI, with 11.47% sensitivity improvement. Moreover, Spio-enhanced MRI detected more lesions that baseline MRI in 5/18 patients (27.78%). PD/T2 SE images were the most sensitive ones, followed by T2* GE and finally by T1 SE. Nearly all HCC nodules (17/18), all metastatic lesions and the cholangiocarcinoma did not take up iron oxide and were relatively hyperintense to the liver. However, in one well-differentiated HCC, the nodule partially took up the contrast agent and became isointense, with high-signal borders on PD/T2 SE images. Both the dysplastic lesion and FNH took up iron oxide; the former was isointense to the liver, while the latter appeared slightly hyperintense, with a high-signal central scar. Finally, hemangiomas became hyperintense on Spio-enhanced T1 SE images and had slightly decreased signal intensity on Spio-enhanced T2 SE images. CONCLUSIONS: In our experience iron oxide was an effective contrast material. Spio-enhanced MRI improved the detection and characterization of focal liver lesions relative to baseline MRI. Several liver-specific contrast agents are now available or in an advanced experimental stage. Therefore, future studies could be aimed at assessing the effectiveness of iron oxide versus other contrast agents and at establishing the role of Spio-enhanced MRI versus spiral CT and CT during arterial portography.

Adult↗
PubMed1997

Effects of ethanol consumption on hepatic hemodynamics in patients with alcoholic cirrhosis.

BACKGROUND & AIMS: Increased portal blood flow represents a compensatory mechanism preventing hepatic hypoxia after ethanol consumption. In addition, alcohol increases hepatic vascular resistance. Thus, ethanol consumption, by increasing hepatic vascular resistance and portal flow, may worsen portal hypertension in patients with cirrhosis. The aim of this study was to investigate the effects of ethanol consumption on hepatic hemodynamics in patients with alcohol-induced cirrhosis. METHODS: Measurements of hepatic venous pressure gradient (HVPG), azygos blood flow, hepatic blood flow, heart rate, and arterial pressure were obtained in 16 patients with alcohol-induced cirrhosis and portal hypertension before and after random administration of a noncaloric fruit drink (250 mL, n = 7) or of an identical beverage plus 0.5 g/kg of ethanol (n = 9). RESULTS: Vehicle caused no effects. By contrast, ethanol increased HVPG (P < 0.0001). The increase in HVPG was maximum at 15 minutes and remained significant at 45 minutes (P < 0.05 vs. vehicle). Ethanol increased azygos blood flow (P < 0.05) without changes in hepatic blood flow. Heart rate and arterial pressure slightly increased. CONCLUSIONS: Oral ethanol consumption increases portal pressure and portocollateral blood flow in patients with alcohol-induced cirrhosis. These findings suggest that even moderate alcohol consumption worsens the portal-hypertensive syndrome and, therefore, may increase the risk of variceal bleeding in patients with alcohol-induced cirrhosis.

Adult↗
PubMed1997

Platelet cytosolic calcium concentration in patients with liver cirrhosis. Relationship with hepatic and systemic hemodynamics.

BACKGROUND/AIMS: Due to structural and functional similarities between platelets and vascular smooth muscle cells, platelet cytosolic calcium concentration ([Ca2+]i) has been suggested to be a useful tool to study regulatory mechanisms of peripheral vascular tone. The aim of the present study was to investigate platelet [Ca2+]i in patients with cirrhosis and whether this parameter is related with the systemic and splanchnic vasodilatation found in these patients. METHODS: Seventeen patients with cirrhosis and eight age- and sex-matched controls were studied. Mean arterial pressure, cardiac output, femoral blood flow and basal and thrombin-stimulated platelet [Ca2+]i were measured. Cardiac output (thermal dilution), azygos blood flow, hepatic venous pressure gradient and hepatic blood flow were also measured in patients with cirrhosis. RESULTS: Patients with cirrhosis had severe portal hypertension and a significantly higher cardiac output and femoral blood flow and a significantly lower systemic and femoral vascular resistance than controls. Patients with cirrhosis had a lower basal platelet [Ca2+]i than normal subjects. However, there was no relationship between platelet [Ca2+]i and any of the hemodynamic parameters that evaluate systemic or splanchnic vasodilatation. CONCLUSIONS: This study shows that cirrhotic patients with portal hypertension have a significant reduction in platelet basal [Ca2+]i. The lack of correlation between platelet [Ca2+]i and hepatic and systemic hemodynamics does not support the use of platelet [Ca2+]i as a model to study mechanisms involved in the pathophysiology of the hyperdynamic circulation associated to portal hypertension.

Blood Platelets↗
PubMed1997

Natural history. Clinical-haemodynamic correlations. Prediction of the risk of bleeding.

Promoting the development of oesophageal varices and ascites, portal hypertension dominates the clinical course of cirrhosis. Varices appear in patients with portal pressure gradient above 10 mmHg and enlarge in 10-20% within 1-2 years of their detection. Bleeding occurs in patients with portal pressure gradient above 12 mmHg when the wall tension causes the rupture of varices, with an incidence of about 10% per year. Indicators of bleeding risk are portal pressure gradient, variceal pressure, large varices and liver dysfunction. Mortality per bleeding episode is 30-50%. Among survivors 60% will rebleed and 30% will die in the following year. The risk of rebleeding decreases in patients with spontaneous or treatment induced reduction of portal pressure gradient or variceal pressure. Ascites develops in almost all patients along the course of the disease. Median survival after its appearance is less than 2 years. Less than 5% of cirrhotic patients die without ascites or without a previous bleeding. Thus portal hypertension is a major determinant of survival in cirrhosis.

Acute Disease↗
PubMed1996

Effects of isosorbide-5-mononitrate on variceal pressure and systemic and splanchnic haemodynamics in patients with cirrhosis.

BACKGROUND: Isosorbide-5-mononitrate is a long-acting nitrovasodilator which was introduced for the treatment of portal hypertension because of its capacity to reduce portal pressure. In contrast to vasoconstrictors, isosorbide-5-mononitrate acts primarily by decreasing portal-collateral resistance without deleterious effects on liver function, although at high doses, a reflex splanchnic vasoconstriction elicited by the fall in arterial pressure may further decrease portal pressure. However, there is no information on the effects of isosorbide-5-mononitrate on variceal pressure, which is thought to be a major determinant of variceal haemorrhage. METHODS: We investigated the effects of isosorbide-5-mononitrate (40 mg, orally; n = 12) or placebo (n = 10) on variceal pressure (non-invasive endoscopic gauge) and hepatic haemodynamics in 22 patients with cirrhosis. RESULTS: Placebo administration had no significant effects. In contrast, isosorbide-5-mononitrate significantly reduced variceal pressure (from 13.5 +/- 3.6 to 9.8 +/- 3.2 mmHg, p < 0.005). This was associated with a fall in wedged hepatic venous pressure (from 28 +/- 5.8 to 25.9 +/- 6.2 mmHg, p < 0.005), hepatic venous pressure gradient (from 20 +/- 4 to 18 +/- 4.7 mmHg, p < 0.005) and azygos blood flow (from 668 +/- 197 to 597 +/- 160 ml/min, p < 0.05), suggesting that the decrease in variceal pressure caused by isosorbide-5-mononitrate could be caused by both reductions in collateral resistance and collateral blood flow. Isosorbide-5-mononitrate moderately reduced mean arterial pressure (-13 +/- 16%; p < 0.005), its fall being directly related to the fall in hepatic venous pressure gradient (r = 0.6, p < 0.01). CONCLUSIONS: The results of this study show that isosorbide-5-mononitrate markedly and significantly reduces variceal pressure in patients with cirrhosis and provide further support for its clinical use in the pharmacological treatment of portal hypertension.

Aged↗