PubMed Health⌕ Search

Biomedical subjects

P Carraro

Publications and source records attributed to P Carraro.

At least 19 recordsLinked to original sources
PubMed2004

An experimental swine model of small bowel cross transplantation.

AIM: In this study we evaluated the possibility of performing a cross small bowel transplantation (CrSBTx) in which, at the same time, 2 pigs were both donors and later recipients of intestinal grafts. The hemodynamic and metabolic impact of this original transplantation model on the animals was determined. METHODS: Ten large White adult female pigs underwent a 2 stage procedure. The principal intraoperative hemodynamic and metabolic parameters were measured at different times during the operation. In the 3 days that followed the operation, renal function, liver and pancreatic damage were investigated. RESULTS: Our surgical model permits us to keep excellent hemodynamic and metabolic stability with low mortality. CONCLUSION: The need of half of animals with respect to conventional models represents an ethical and economic advantage of CrSBTx and we propose it for intestinal transplant studies in large animals.

Animals↗
PubMed2002

ALEX (artificial liver for extracorporeal xenoassistance): a new bioreactor containing a porcine autologous biomatrix as hepatocyte support. Preliminary results in an ex vivo experimental model.

Long-term maintenance of viability and expression of differentiated hepatocyte function is crucial for bioartificial liver support. We developed a new bioreactor design (ALEX), associated with a new extracellular autologous hepatocyte biomatrix (Porcine Autologous Biomatrix - PBM) support. To test this new bioreactor, we compared it to a standard BAL (BioArtificial Liver) cartridge in a ex vivo model using human plasma added to bilirubin, ammonium and lidocaine. A pathology study was performed on both bioreactors. The results suggest that ALEX allows a maximal contact between the perfusing plasma and the liver cells and a proper hepatocyte support by a cell-to-matrix attachment. ALEX is a suitable cell support bioreactor, guaranteeing long-term maintenance of the metabolic activity of hepatocytes when compared to a standard BAL cartridge.

Ammonia↗
PubMed2001

Point-of-care testing of cardiac markers: results from an experience in an Emergency Department.

AIM: An experimental approach to the use of point-of-care testing for cardiac markers in the Emergency Department (ED) of our Institution has been carried out using two devices (SCS, Dade Behring and Triage Cardiac Panel, Biosite Diagnostics) for the measurement of cardiac markers. RESULTS: (1) From the analytical point of view, a fundamental tool for an efficient management of patients was the agreement between results from point-of-care testing and from the instruments located in STAT lab and/or central laboratory: in about 5% of patients, a lack of comparability of data, resulted in an inappropriate admission of patients (medical vs. intensive care unit). (2) The actual total turnaround time (TAT) in the management of samples sent to STAT lab was estimated to be equal to 82.5 min (50th percentile). (3) In the same organizational setting, the use of a point-of-care device produced a turnaround time equal to 17 min (50th percentile). (4) The reduction in turnaround time resulted in a faster discharge for five patients who had normal ECG findings and cardiac marker values, the Delta time (POCT-STAT lab) ranging from -10 to -70 min. CONCLUSIONS: The point-of-care option evaluated also in relation to personnel issues for staff working in the ED, brought some interesting questions about the characteristics of POCT devices (easy to use 100%, safety for operator 91%) and the obtained results (quantitative and correlated to STAT lab, 91%), as well as the need of other options such as the implementation of rapid tube sample delivery.

Attitude of Health Personnel↗
PubMed2001

Tissue factor pathway inhibitor release induced by defibrotide and heparins.

We evaluated the release of tissue factor pathway inhibitor (TFPI) induced by defibrotide (DF), a single-stranded, negatively charged polydeoxyribonucleotide extracted from mammalian organ. Ten normal volunteers were injected with an intravenous bolus of 400 mg DF and 2,000 IU unfractionated heparin (UFH). In addition, three volunteers were also injected with an intravenous bolus of 2,000 anti-Xa U of two low-molecular-weight heparins (LMWHs), enoxaparin and nadroparin. UFH caused a 4-fold increase in plasma TFPI at 5 minutes, with a decrease that was parallel to the heparin level measured by the anti-Xa assay. However, at 80 minutes, although the plasma anti-Xa activity of UFH was almost undetectable, the level of TFPI remained 2-fold baseline. DF induced an increase of TFPI that was 2-fold higher than the baseline level, with a steady state achieved between 5 and 20 minutes. At 40 minutes, the TFPI levels returned to basal level. This pattern was not coincident with the clearance of DF and at 40 minutes, the concentration of DF was still one third of the levels at 5 minutes (25.4 +/- 4.04 microg/mL). Both of the LMWHs induced a similar TFPI peak level at 5 minutes (1.5-fold increase) and at 40 minutes the TFPI levels returned to the initial levels. At 5 minutes, both LMWHs showed a higher plasma anti-Xa activity than UFH, which was detectable even at 80 minutes. The current study demonstrated that one of the mechanisms of the antithrombotic activity of DF is mediated via TFPI. Furthermore, the release of TFPI by heparin is mediated by non-antithrombin III binding fragments. Thus, polyanionic electrolytes are capable of releasing TFPI irrespective of their antithrombin III effect.

Adult↗
PubMed2001

Comparison of pig, human and rat hepatocytes as a source of liver specific metabolic functions in culture systems--implications for use in bioartificial liver devices.

The limited availability of human hepatocytes results in the use of animal cells in most bioartificial liver support devices. In the present work, clinically relevant liver specific metabolic activities were compared in rat, pig and human hepatocytes cultured on liver-derived biomatrix to optimize the expression of differentiated functions. Pig hepatocytes showed higher rates of diazepam metabolism (2.549+/-0.821 microg/h/million cells vs. 0.474+/-0.079 microg/h/million cells rats, p<0.005, and vs. 0.704+/-0.171 microg/h/million cells in man, p<0.005) and of bilirubin conjugation (21.60116+/-8.433237 micromoles/l/24 h vs. 6.786809+/-2.983758 in man, p<0.001 and vs. 9.956538+/-1.781016 micromoles/l/24 h in rats, p<0.005). Urea synthesis was similar in pig and in human hepatocytes (150+/-46.3 vs. 144.8+/-21.46 nmoles/h/million cells) and it was lower in rats (84.38+/-35.2; p<0.001 vs. man, p<0.02 vs. pig). High liver specific metabolic activities in cultured pig hepatocytes further support their use as a substitue for human cells in bioartificial liver devices.

Animals↗
PubMed2000

Proteases in gastrointestinal neoplastic diseases.

Cysteine and serine proteases are involved in cancer invasion and metastasis. In the past few years we investigated the tissue levels of these proteases in gastric cancer (GC), gastric precancerous changes (CAG), colorectal cancer (CRC) and the plasma and serum levels of proteases in several gastrointestinal tumours, using ELISA methods. Significantly higher antigen levels were found not only in GC tissue but also in CAG with respect to the levels found normal tissue; with respect to CAG, patients with dysplasia had higher levels than patients without dysplasia. The same findings were obtained in CRC. In general protease levels correlated with the major histomorphological parameters, such as grading and histotype in GC as well as in CRC. Tissue protease levels had a strong prognostic impact in GC, in which UPA was singled out by multivariate analysis as the major prognostic factor, and CRC. The plasma levels of urokinase-type plasminogen activator (UPA) and the serum levels of cathepsin B were significantly increased in patients with gastrointestinal tumours. In conclusions, cysteine and serine proteases may have a part not only in GC and CRC invasion and metastasis, but also in the progression of gastric precancerous changes into cancer. They are strong prognostic factors in GC and CRC. These proteases may also have a role as tumour markers in the early diagnosis of gastrointestinal tract tumours.

Biomarkers, Tumor↗
PubMed2000

Increased fibrinogen production in type 2 diabetic patients without detectable vascular complications: correlation with plasma glucagon concentrations.

Fibrinogen is a strong cardiovascular risk factor in the general population, and increased fibrinogen plasma concentrations have been reported in type 2 diabetic patients. However, the mechanisms leading to hyperfibrinogenemia in type 2 diabetes are not known. It is also not known whether possible alterations of fibrinogen turnover may precede clinical diabetic micro- and macrovascular complications and therefore potentially contribute to their onset. To address these questions, fibrinogen production was determined in six male type 2 diabetic patients without detectable micro- and macrovascular complications (age, 45 +/- 4 yr; body mass index, 27 +/- 0.9 kg/m2) and in seven nondiabetic matched controls using leucine isotope precursor-product relationships. Plasma glucose (P < 0.001), insulin (P < 0.05), and glucagon concentrations (P < 0.01) were increased in the patients. Diabetic patients also had increased plasma fibrinogen concentration (+ approximately 50%; P < 0.01) and pool (+ approximately 40%; P < 0.01) as well as fractional (+ approximately 35%; P = 0.08) and absolute (+ approximately 100%; P < 0.01) synthetic rates. The plasma glucagon concentration was positively related (P < 0.005 or less) to the fibrinogen concentration as well as to fractional and absolute synthetic rates. Thus, fibrinogen production is markedly enhanced, and this alteration is likely to determine the observed hyperfibrinogenemia in type 2 diabetic patients. Hyperglucagonemia may contribute to the increased fibrinogen production. These findings in normoalbuminuric patients without clinical complications support the hypothesis that increased fibrinogen production and plasma concentrations may precede and possibly contribute to the onset of clinical cardiovascular complications in type 2 diabetes.

Adult↗
PubMed1999

Procoagulant effect of anti-beta2-glycoprotein I antibodies with lupus anticoagulant activity.

Prothrombin time (PT) is routinely used to monitor oral anticoagulant treatment in patients with the antiphospholipid antibody syndrome (APS). The fact that PT is a phospholipid (PL)-dependent coagulation test raises the possibility that lupus anticoagulant (LA) might interfere with this test, thus complicating the control of anticoagulant treatment. The effect of 6 affinity-purified preparations of anti- (a)beta2-glycoprotein I (GPI) antibodies with LA activity on the PT was tested. Instead of prolonging PT as expected, the abeta2-GPI antibodies reduced the PT of both normal plasma and anticoagulated plasma by a mean of 2.4 seconds and 5.6 seconds, respectively. This effect was also observed using other 5 commercially available preparations of thromboplastin. The abeta2-GPI-mediated reduction in PT was dose-dependent and was lost upon removal of beta2-GPI. The failure of abeta2-GPI antibodies to express LA activity in PT was found to depend on the fact that calcium ions were added together with PL at the beginning of the assay. In fact, modification of the standard diluted Russell viper venom time (dRVVT) test by adding calcium ions together with PL resulted in a loss of abeta2-GPI anticoagulant activity. The procoagulant effect was not as evident in an assay that used stimulated monocytes as a source of thromboplastin. These results show that abeta2-GPI antibodies exhibit an 'in vitro' procoagulant effect in PT and an anticoagulant effect in dRVVT only when the interaction with their antigen and PL occurs in the absence of calcium ions.

Antibodies↗
PubMed1999

The role of cysteine and serine proteases in colorectal carcinoma.

BACKGROUND: Cathepsin B (CATB) and cathepsin L (CATL), which are cysteine proteases, urokinase-(UPA) and tissue-type plasminogen activator (TPA), both serine proteases, and their inhibitor type-1 (PAI-1) are believed to play an important role in colorectal carcinoma (CRC) invasion and metastasis. The objective of this study was to measure CATB, CATL, UPA, TPA, and PAI-1 in the same cancerous tissue (CANCER) and in tissues obtained from a tumor free area (NORMAL) to compare their respective prognostic roles in patients with CRC. METHODS: CANCER and NORMAL samples were obtained from 60 CRC patients undergoing surgery (36 males and 24 females; mean age, 63.8 years [range, 27-85 years]). The antigen concentrations were measured using an enzyme-linked immunoadsorbent assay method. The CANCER tissue also was examined in terms of major histomorphologic parameters such as differentiation, vascular invasion, degree of necrosis, and mucus production. RESULTS: Significantly higher antigen levels were found: 1) in CANCER versus NORMAL (with respect to CATL, UPA, and PAI-1, with significantly lower levels for TPA); 2) in CRC with versus without metastasis (CATB, CATL, and PAI-1); 3) in poorly versus well differentiated CRC (UPA and PAI-1); and 4) in advanced Dukes stages (PAI-1). CATB and CATL significantly correlated with UPA and PAI-1. Finally, CATL (P = 0.0001), UPA (P = 0.006), PAI-1 (P = 0.006), Dukes stage (P = 0.0001), presence of metastases (P = 0.003), and vascular invasion (P = 0.03) had a significant prognostic impact. CONCLUSIONS: The simultaneous up-regulation of cysteine and serine proteases in CRC confirms their role in colorectal tumor biology and particularly in the process of invasion and metastasis. Together with Dukes stage, determinations of CATL, UPA, and PAI-1 have a major prognostic impact in patients with CRC.

Adult↗
PubMed1999

[The role of cathepsins and the plasminogen activator/inhibitor system in colorectal cancer].

Cysteine proteases [Cathepsin B and L (CATB, CATL)] and the serine protease urokinase type plasminogen activator (UPA) with its inhibitor type-1 (PAI-1) are thought to play an important part in colorectal cancer invasion and metastasis. To our knowledge, however, cathepsins and plasminogen activator/inhibitor system have not been evaluated in the same study. The authors using the ELISA method, determined the protease antigen concentrations in colorectal cancer tissue and in normal tissue distant from tumour, in 35 patients with colorectal cancer. They also evaluated the relationship that these proteases may have with the major histomorphological parameters and tumour staging. Significantly higher antigen levels were found: 1. in cancerous tissue vs. tumour free tissue (CATB, CATL, UPA, PAI-1); in colorectal cancer with vs. without metastasis (CATB, CATL, UPA, PAI-1); 3. in poorly vs. well differentiated tumours (CATB, UPA, PAI-1); 4. in advanced Dukes' stages (CATB, UPA, PAI-1). The simultaneous activation of cathepsins and plasminogen activator/inhibitor system in colorectal cancer confirms their role in colorectal tumor biology and particularly in the process of invasion and metastasis. Our results suggest the possible prognostic impact of these proteases in colorectal cancer.

Cathepsins↗
PubMed1998

The effect of heparin on trinitrobenzene sulphonic acid-induced colitis in the rat.

BACKGROUND: Reduced blood coagulability seems to protect against inflammatory bowel disease; pilot studies using heparin in patients with inflammatory bowel disease have reported positive results. AIM: To evaluate the effects of heparin treatment on microangiographic and on inflammatory parameters in experimental colitis, induced by trinitrobenzene sulphonic acid (TNBS)-ethanol. METHODS: Four groups of rats: (i) controls (saline enema), TNBS-induced colitis with (ii) sham treatment (saline, s.c.), (iii) dexamethasone (0.25 mg/kg/day s.c.) and (iv) heparin (500 U/kg t.d.s., s.c.). Microangiography was performed 2 and 4 days after colitis induction. Partial thromboplastin time, colonic wet weight, macroscopic damage score and mucosal myeloperoxidase (MPO) activity were determined at day 4. RESULTS: TNBS-induced colitis caused a reduction in visible bowel wall vessels, which was prevented by heparin (P < 0.05) but not by steroids. The macroscopic damage scores and colon wet weights were similar in all colitis groups. Compared to untreated colitis the MPO activity in heparin-treated animals was of borderline significance. CONCLUSIONS: Heparin treatment improved microangiographic features and reduced inflammation to a certain degree. Steroids delayed development of colon hypoperfusion, but were ineffective on MPO activity. It remains to be determined if the observed effects are due to the antithrombotic activity of heparin or to an anti-inflammatory action.

Animals↗
PubMed1998

External Quality Assessment of stat test intralaboratory turnaround times. Pilot study from the Members of the Working Group for the Standardization and Promotion of Turnaround Time Control under the Auspices of the Comitato Italiano per la Standardizzazione dei Metodi Ematologici e di Laboratorio.

We describe procedures, results and prospects of a pilot program in External Quality Assessment (EQA) of the stat test intralaboratory turnaround times. Our goals are to promote quality by systematic monitoring and comparison of performances by laboratories, continuous investigation into the state of the art of the processes from receipt of sample to transmission of results and creation of a data base for standardization of measures and definition of consensus values for turnaround time. Of 30 laboratories invited to participate, 25 took part, agreeing to record times of arrival and transmission for all determinations of three analytes (blood hemoglobin, serum/plasma potassium and plasma prothrombin time) for seven consecutive days and to continue for one or more further periods of seven days as necessary if there were less than 300 determinations for each analyte. Within a preset time limit, data were sent by e-mail on an Excel file and we sent back two reports per analyte, showing: i) the graph for time vs. percentage of tests completed and several measures of turnaround time; ii) results of all laboratories in graph form, allowing each laboratory to identify only its own data. The high proportion of participating laboratories among those invited (83%) encourages us to implement the EQA program systematically, on a half-yearly basis, extending it to all laboratories wishing to participate in Italy or elsewhere in Europe.

Italy↗
PubMed1997

Accuracy of two newly described D-dimer tests in patients with suspected deep venous thrombosis.

Accumulating evidence suggests that the ELISA determination of D-Dimer might be a useful tool for the exclusion of deep vein thrombosis (DVT) of lower extremities, because of its high sensitivity and negative predictive value. However, conventional ELISA assay is time-consuming and, therefore, is not suitable for emergency use. To evaluate the accuracy of two rapid assays recently described, 126 consecutive outpatients with the clinical suspicion of DVT underwent the NycoCard D-Dimer and the Instant I.A. D-Dimer determination, using venography as the reference test. In all patients, the conventional ELISA assay was also performed. Venography confirmed the presence of DVT in 30 patients (23.8%), and ruled out the diagnosis in the remaining 96. Instant I.A D-Dimer was positive in 28 patients with DVT (sensitivity, 93.3%), and negative in 90 subjects free from thrombosis (specificity, 93.8%). Nycocard D-Dimer correctly identified 27 patients with DVT (sensitivity 90.0%), and was negative in 77 subjects free from thrombosis (specificity, 80.2%). Sensitivity, specificity, negative and positive predictive values of both tests did not differ from those found with the classic ELISA method. In conclusion, both Instant I.A. D-Dimer and Nycocard D-Dimer assays show a great potential for clinical use.

Adult↗