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P Villa

Publications and source records attributed to P Villa.

At least 37 records · Page 2Linked to original sources
PubMed2001

Evaluation of an automated method for the quantification of von Willebrand factor antigen. Its application in the study of vascular dysfunction.

BACKGROUND AND OBJECTIVES: Abnormally high levels of von Willebrand factor (VWF) have been described as a response to physiologic and chronic alterations. It is therefore of great interest to have sensitive, accurate, fast and easy to use assays to quantify VWF. The aim of this study was to evaluate the performance characteristics of the immunoturbidimetric assay IL Test VWF:Ag and the use of this determination in the study of vascular dysfunction. DESIGN AND METHODS: The reproducibility, accuracy and linearity of the method were determined. A method comparison study was performed using an ELISA as the reference test. The assay reference range and its age-dependence were established. To evaluate the utility of the assay in vascular dysfunction, a cohort of 30 type 1 diabetes mellitus (DM) patients were analyzed, 11 of whom showed microvascular complications. RESULTS: The linearity range found was 10-150 IU/dL. Reported values above 150 IU/dL should be diluted and reanalyzed, expanding the range up to 600 IU/dL. The coefficients of variation were below 5% and inaccuracies below +/-15% within the linearity range. The comparison with the reference ELISA showed a good correlation coefficient (r = 0.985, VWF values from 5-680 IU/dl). The reference range was found to be 40.8 - 158.1 IU/dL. Significant differences between the DM type 1 patients with microvascular complications and a sex-age matched control group were observed. This difference was not observed for the DM patients not showing vascular alterations. INTERPRETATION AND CONCLUSIONS: The method is reproducible, accurate and linear. The assay correlates well with the reference ELISA. There is a relationship between patients showing microvascular diabetic complications and high levels of VWF:Ag. The assay is easy to perform, fully automated, and suitable for analyzing a small number of samples.

Adolescent↗
PubMed2001

Low level of circulating activated protein C is a risk factor for venous thromboembolism.

The levels of circulating activated protein C (APC) reflect in vivo protein C activation. The aim of this study was to determine whether a low APC level is an independent risk factor for venous thromboembolism (VTE). We measured APC in 160 patients with a history of VTE and without recognized thrombophilic defects, and in 199 healthy individuals. The mean (+/- SD) APC level was lower in patients (0.99 +/- 0.44 ng/ml) than in controls (1.19 +/- 0.41 ng/ml) (p < 0.0001), and showed a different distribution in the two groups. Thirty-eight patients (23.7%) had APC levels below the 5th percentile of the control group (<0.69 ng/ml) and 57 patients (35.6%) had APC levels below the 10th percentile (<0.77 ng/ml). APC levels <0.69 ng/ml increased the risk of a single or recurrent episode of VTE 4.2-fold (95% confidence interval, 2.0-9.0) or 6.9-fold (2.6-17.9). respectively, and APC levels <0.77 ng/ml increased these risks 3.4-fold (1.9-6.2) or 5.1-fold (2.3-11.2), respectively, compared with controls. Familial studies revealed that in some cases the low APC phenotype seems to be hereditary. We conclude that a low level of circulating APC in individuals without any of the most recognized thrombophilic defects is a prevalent, independent risk factor for VTE, and that it predisposes to recurrent VTE.

Adult↗
PubMed2000

Synthesis and amphiphilic properties of glycosyl-1,4-benzodiazepin-2,5-diones.

Glycosyl-1,4-benzodiazepin-2,5-diones were prepared by coupling polyhydroxylated groups at N-1 of the corresponding benzodiazepine. The groups include 1-deoxy-D,L-xylit-1-yl, 6-deoxy-D-glucopyranos-6-yl, and 6-deoxy-3-OR-D-glucopyranos-6-yl (R = n-CnH(2n +1); n = 8, 12, and 16). The structural variations of the sugar group allowed comparison of such amphiphilic data as water solubility (Sw), critical micelle concentration (CMC), and corresponding surface tension (gamma) values. At 25 degrees C, unsubstituted benzodiazepines have Sw values from 0.9 to 4.2 10(-3) mol L(-1), whereas xylit-1-yl and 6-deoxy-D-glucopyranos-6-yl derivatives are, respectively, 7.4-25 and 58-204 times more soluble. Also, compounds with R = n-C8H17 are more soluble than corresponding benzodiazepines (1.4-5.8 times) and give micelles with CMC from 2.7 to 5.6 10(-3) mol L(-1) and corresponding gamma from 29 to 37 mN m(-1). In contrast, compounds with R = n-C12H25 and n-C16H33 are not soluble enough to reach the critical micelle concentration.

Benzodiazepinones↗
PubMed2000

Increased peripheral benzodiazepine binding sites and pentraxin 3 expression in the spinal cord during EAE: relation to inflammatory cytokines and modulation by dexamethasone and rolipram.

We have studied the mRNA expression of pentraxin 3 (PTX3) and the binding of the peripheral-type benzodiazepine receptor (PBR) ligand, [3H]-PK11195, in the spinal cord of Lewis rats where EAE was actively induced. PTX3 was induced during the active phase of EAE (day 10-14), it remained high up to 30 days and disappeared only 60 days later. Similarly, PK11195 binding peaked at day 14-17 during the recovery and it disappeared by day 60. On the other hand, the levels of TNF and IL-6 in the spinal cord were elevated at the peak and at the onset of clinical signs and returned to non-detectable by day 14-17. Dexamethasone abolished all these changes, while treatment with rolipram, delayed the appearance of the disease and then decreased its severity. However the peaks of TNF, IL-6, PBR and PTX3 levels in spinal cord were only delayed, but not reduced, by rolipram treatment. In conclusion, we show two types of inflammatory changes in EAE: acute, short term changes (TNF and IL-6), that correlate with the disease; and effects such as PTX3 expression and PK11195 binding that last longer after recovery from the disease.

Animals↗
PubMed2000

Increased tumor necrosis factor and interleukin-6 production in the central nervous system of interleukin-10-deficient mice.

Interleukin-10 (IL-10) inhibits tumor necrosis factor (TNF) production. We investigated the role of endogenous IL-10 in brain TNF production. We injected IL-10-knockout mice with lipopolysaccharide (LPS,2.5 microg/mouse i.c.v.). Brain TNF and IL-6 levels were more elevated and persisted longer in IL-10-deficient mice compared with wild type mice, suggesting that IL-10 is an important negative feedback inhibitor of TNF and IL-6 production in the CNS.

Animals↗
PubMed2000

Proteins of rat serum V: adjuvant arthritis and its modulation by nonsteroidal anti-inflammatory drugs.

The effect of adjuvant arthritis (AA) on the pattern of rat serum proteins includes the upregulation of haptoglobin, orosomucoid, alpha2-macroglobulin, serine protease inhibitor-3, thiostatin, alpha1-antitrypsin, C-reactive protein, and the downregulation of kallikrein-binding protein, alpha1-inhibitor III, apolipoprotein A-I, alpha2-HS-glycoprotein, albumin, apolipoprotein A-IV, transthyretin and transferrin. Minor changes (+/- 20%) are observed for Gc-globulin, ceruloplasmin, and alpha1-macroglobulin. AA thus grossly resembles the acute inflammatory response elicited by the injection of turpentine, although the changes in the levels of negative acute-phase proteins (APP) are smaller in acute inflammation. Indomethacine and ibuprofen inhibit the effects of arthritis on the synthesis of rat serum proteins in different ways: The former is, on average, three times as effective as the latter. Each drug interferes differently with different proteins. In animals without AA, both nonsteroidal anti-inflammatory drugs (NSAID) mimic the inflammatory pattern to a certain extent, with more effect on the negative than on the positive APPs. Overall, the shifts in serum protein levels parallel changes in inflammatory parameters such as joint swelling and serum interleukin-6 (IL-6) activity. Protein quantitation after two-dimensional electrophoresis (2-DE) reveals some effects of the drugs per se which escape detection by other routine tests.

Animals↗
PubMed2000

Synthesis and antifungal activity of novel bisdithiocarbamate derivatives of carbohydrates against Fusarium oxysporum f. sp. lini.

Novel carbamic esters possessing a carbohydrate moiety derived from glycerol or D-glucose with two N,N-diethyldithiocarbamoyl groups and a series of bisdithiocarbamic esters having a ketone or an alkyl ester have been synthesized. The in vitro activity of these new compounds was evaluated against Fusarium oxysporum f. sp. lini. Some of the compounds [bis[1,3-S-(N,N-diethyldithiocarbamoyl)]-1, 3-dideoxyglycerol) and diethyl N,N'-(1,3-dideoxyglycer-1, 3-diyl)bis(dithiocarbamate)] were more active for inhibiting vegetative mycelium growth than, respectively, the commercial N, N-diethyldithiocarbamic acid sodium salt and Maneb. The structure activity of these new compounds is discussed.

Fungicides, Industrial↗
PubMed2000

PAI-1 promoter 4G/5G genotype as an additional risk factor for venous thrombosis in subjects with genetic thrombophilic defects.

Impaired fibrinolysis as a result of increased plasminogen activator inhibitor-1 (PAI-1) levels in plasma is a common finding in patients with deep vein thrombosis (DVT). A 4G/5G polymorphism in the promoter region of the PAI-1 gene has been reported to influence the levels of PAI-1. The 4G allele was found to be associated with higher plasma PAI-1 activity (act), but contradictory results on the incidence of the 4G allele in DVT patients have been reported. The aim of this study was to analyse whether the PAI-1 promoter 4G/5G genotype increases the risk of venous thrombosis in subjects with thrombophilic defects, and to determine the distribution of the PAI-1 4G/5G genotype and its relation to plasma PAI-1 levels in 190 unrelated patients with DVT in comparison with a control group of 152 healthy subjects. No differences between the 4G/5G allele distribution in the DVT group (0.43/0.57) and in the control group (0.42/0.58) were observed. However, the presence of the 4G allele significantly increased the risk of thrombosis in patients with other thrombophilic defects. Significantly higher PAI-1 levels were observed in DVT patients than in the controls. Our results also showed significant differences in the plasma levels of PAI-1 antigen (ag) and PAI-1 act among the 4G/5G genotypes in DVT patients. A multivariate analysis revealed that, in the DVT group, PAI-1 ag levels were influenced by the 4G allele dosage, triglyceride levels and body mass index (BMI). The influence of the 4G allele dosage on PAI-1 levels was independent of the triglyceride levels and BMI. In the control group, no significant correlation between PAI-1 levels and 4G allele dosage was observed. In conclusion, the PAI-1 promoter polymorphism was found to have an influence on PAI-1 levels in DVT patients and on the risk of venous thrombosis in subjects with other genetic thrombophilic defects.

Adult↗
PubMed2000

Decrease in brain cytochrome P450 enzyme activities during infection and inflammation of the central nervous system.

The effect of infection and inflammation of the central nervous system (CNS) on cytochrome-P450-dependent activities in brain, spinal cord and liver microsomes was determined. For this, two models were used: (1) the intracerebroventricularly injected lipopolysaccharide (LPS) model and (2) the experimental auto-immune encephalomyelitis (EAE) model. In the LPS model, aminopyrine N-demethylase (AMND) and ethoxycoumarin O-deethylase (ECOD) activities (both P450 dependent) were significantly decreased (35 and 20%, respectively) in brain microsomes. In the EAE model, only ECOD activity was significantly lower (18%). In the liver, a decrease in total P450, AMND and ECOD activities was only observed in the LPS model. In both models, tumour necrosis factor (TNF) was significantly elevated in brain and spinal cord tissues. In serum, TNF was only detectable in the LPS model. It is concluded that an infection or inflammation located in the CNS, which is accompanied by high TNF levels, results in a decrease in P450-dependent metabolism not only in the liver but in the brain as well.

7-Alkoxycoumarin O-Dealkylase↗
PubMed2000

Congenital and acquired thrombotic risk factors in women using oral contraceptives: clinical aspects.

We describe the thrombophilic and clinical characteristics of a group of patients who suffered venous thrombosis (VT) (n = 36) and ischemic stroke (n = 8) while taking oral contraceptives (OC). Our purpose is to ascertain whether there are differences between users of second and third generation progestogen and to investigate the influence of concurrent congenital and acquired risk factors (other than OC) on the onset of the thrombosis. The group of patients included 36 women with VT and eight with ischemic stroke. The patients' recognized predisposing factors were recorded. We also considered age, length of time on OC, types of OC, rethrombosis, family history of VT, and the presence of thrombophilic genetic defects. In the group of patients with VT, 54% were treated with second generation OC (n = 23), and 30% (n = 11) were treated with third generation OC. We found no significant statistical differences with respect to age and length of time on OC between the two types of OC. The prevalence of genetic defects in these patients--factor V (FV) Leiden, prothrombin G20210A mutation and protein S deficiency--was 19% (n = 7), 17% (n = 6), and 8% (n = 3) respectively. We observed the shortest time lapse between initiating OC and the first thrombotic event in carriers of FV Leiden and in patients with combined defects, but the differences were not significant. In patients with ischemic stroke, 50% were treated with second generation OC and 50% were treated with third generation OC. Prothrombin G20210A mutation was detected in two patients. In both patients,the stroke occurred earlier than in the rest of the patients, but these differences were not statistically significant. With respect to preventing thrombotic events in these patients, our data suggest that OC therapy should be avoided in patients with a previous history of thrombosis and in patients with an evident thrombotic tendency in the family. In patients in whom the family history of thrombosis is not very evident, it would be recommended to screen for FV Leiden, prothrombin G20210A mutation, and protein S, and to rule out OC if the patient does in fact have one of these risk factors. Moreover, if a patient develops a thrombotic complication while taking OC, an evaluation to search for a thrombophilic defect is warranted, and at the same time, alternative methods of contraception should be considered.

Adolescent↗
PubMed2000

Portal vein thrombosis associated to prothrombin G20210A mutation and protein C deficiency.

We describe a patient with left branch portal vein thrombosis involving two thrombophilic alterations, the prothrombin G20210A mutation and protein C deficiency. In spite of not being under anticoagulant treatment, the thrombus in the portal vein underwent complete and spontaneous lysis. No other risk factors were detected and no family history related to thrombosis was found.

Adenine↗
PubMed2000

Intracardiac thrombosis in a case of Behcet's disease associated with the prothrombin 20210G-A mutation.

Thrombosis occurs in 20 to 30% of patients with Behçet's disease (BD), but the precise pathogenic mechanism underlying the thrombotic tendency in these patients is not well known. Venous thromboses are commonly located in the lower extremities, but right intracardiac thrombi are extremely rare. We report for the first time on a young patient with BD associated the 20210G-A prothrombin gene mutation and right intracardiac thrombosis. We suggest that the association of BD with this newly recognized prothrombotic genetic mutation may have contributed to the development of the thrombotic event in this patient.

Adolescent↗
PubMed2000

Quantification of D-dimer using a new fully automated assay: its application for the diagnosis of deep vein thrombosis.

BACKGROUND AND OBJECTIVE: A D-dimer assay can be helpful to rule out thromboembolism provided it is sensitive, reliable, fast and easy to perform. Tests based on the ELISA methodology have a high diagnostic sensitivity, and are therefore adequate for excluding deep venous thrombosis (DVT). The drawbacks are their long assay times, unsuitability to be run on single samples and cost. New methods have been developed, based either on the same principle, by immunofiltration or by microlatex immunoturbidimetric assays which seem to reach the high sensitivity and negative predictive value (NPV) required, but allowing fast and quantitative single sample analysis. The aim of this work was to evaluate one rapid test, a fully automated quantitative assay (IL Test D-dimer, run on an ACL 7000 coagulation analyzer, Instrumentation Laboratory). DESIGN AND METHODS: We compared the diagnostic value of IL Test for DVT with that of an ELISA (Dimertest Gold EIA Agen Biomedical Limited, Acacia Ridge, Australia). Eighty-six patients (43 men, 43 women, mean age: 61 years) showing DVT symptoms formed the population for this non-randomized controlled trial in a referral center. The diagnosis of DVT based on the clinical history, was confirmed by serial compression ultrasonography (CUS) with Doppler flow in 62 patients. RESULTS: The IL Test D-dimer proved to be rapid, automated and well suited for individual tests with a good reproducibility in three control plasmas with different concentrations of D-dimer (coefficient of variation range 0.54-3. 87%). Its performance was comparable to that of the Dimertest Gold EIA, as indicated by the areas under the receiver operating characteristic curves (Dimertest Gold EIA 0.748; IL Test D-dimer 0.70). On the basis of kappa coefficients, there was a good concordance between the Dimertest Gold EIA and IL Test D-dimer when the receiver operating characteristic (ROC) curves suggested cut-offs were used. The sensitivity (98.3%) and NPV (88.9%) shown by IL Test D-dimer are comparable or even better than those obtained for EIA (95%, 80%, respectively). INTERPRETATION AND CONCLUSIONS: This study shows that the new method can be included in prospective clinical trials to test the utility of D-dimer measurement in combination with other non-invasive diagnostic procedures in the management of DVT diagnosis.

Adolescent↗
PubMed2000

Risk of venous thrombosis in carriers of the prothrombin G20210A variant and factor V Leiden and their interaction with oral contraceptives.

BACKGROUND AND OBJECTIVES: The prothrombin G20210A mutation and factor V Leiden have been found to be associated with an increased risk of venous thrombosis, but the reported prevalences of the prothrombin gene variant both in the normal population and in patients with deep venous thrombosis (DVT) vary greatly in the literature. Moreover, the influence of oral contraceptives (OC) on thrombotic events in patients with the prothrombin G20210A variant has not been well established. In this study we evaluate both circumstances. DESIGN AND METHODS: A case-control study was run on 229 patients with DVT and 246 healthy controls. The patients' history of thrombosis and acquired thrombotic risk factors, especially OC, were recorded. Prothrombin G20210A mutation, factor V Leiden, antithrombin, heparin II cofactor, plasminogen and proteins C and S were evaluated. RESULTS: Seven and a half percent of the patients and 2.9% of the controls were carriers of the prothrombin mutation, while 12.2% of the patients and 1.6% of the controls had factor V Leiden. Among the 229 DVT patients there were 130 patients with clinically suspected thrombophilia (first thrombotic event occurring before the age of 45 years or positive family history of thrombosis or recurrent venous thrombosis). Ten percent of these 130 patients were carriers of the prothrombin G20210A mutation and 18.5% had the factor V Leiden mutation. The odds ratios (OR) for DVT risk were: 2.4 (95% CI, 1.0-6.3) for the total DVT patients and 5.2 (95% CI, 1.4-19.5) for the patients with clinically suspected thrombophilia with the prothrombin mutation. The risk of thrombosis was 6.9 (95% CI, 2.3-20.6) for the DVT patients and 14.3 (95% CI, 3.3-64.6) for the patients with clinically suspected thrombophilia with factor V Leiden. Fifty-five percent of the patients with combined congenital defects (prothrombin mutation G20210A plus another congenital defect) had recurrent thrombosis. In women receiving OC the risk of DVT was 3.5 (95% CI, 1.5-8.2) that of the patients not receiving OC. When women with combined defects were also taking OC, the risk of thrombosis increased significantly. INTERPRETATION AND CONCLUSIONS: The prevalence of the prothrombin G20210A mutation in the healthy population in our study is similar to that observed in other southern European countries. The prothrombin G20210A mutation does not by itself seem to be a high thrombotic risk factor. However, when it is present together with other thrombotic risk factors, the predicted risk of thrombotic events increases. The use of OC by women with the prothrombin G20210A variant or FV Leiden, either alone or combined with other thrombotic risk factors, was associated with a significant increase in the risk of venous thrombosis.

Adult↗
PubMed1999

Role of factors downstream of caspases in nuclear disassembly during apoptotic execution.

We used cytoplasmic extracts from chicken DU249 cells at various stages along the apoptotic pathway to analyse the events of apoptotic execution. So-called S/M extracts from morphologically normal 'committed-stage' cells induce apoptotic morphology and DNA cleavage in substrate nuclei. These apoptotic changes appear to require the function of multiple caspases (cysteine aspartases, a specialized class of proteases) acting in parallel. Extracts from 'execution-stage' apoptotic cells induce apoptotic events in added nuclei in a caspase-independent manner. Biochemical fractionation of these extracts reveals that a column fraction enriched in endogenous active caspases is unable to induce DNA fragmentation or chromatin condensation in substrate nuclei, whereas a caspase-depleted fraction induces both changes. 'Execution-stage' extracts contain an ICAD/DFF45-inhibitable nuclease resembling CAD, plus another activity that is required for the apoptotic chromatin condensation. 'Committed-stage' S/M extracts lack these downstream activities. These observations reveal that caspases act in an executive fashion, serving to activate downstream factors that disassemble the nucleus rather than disassembling it themselves. They also suggest that activation of the downstream factors (rather than the caspases) is the critical event that occurs at the transition from the latent to the execution phase of apoptosis.

Animals↗