PubMed Health⌕ Search

Biomedical subjects

Betti Giusti

Publications and source records attributed to Betti Giusti.

At least 19 recordsLinked to original sources
PubMed2006

Role of glycoprotein Ia gene polymorphisms in determining platelet function in myocardial infarction patients undergoing percutaneous coronary intervention on dual antiplatelet treatment.

Response variability to antiplatelet treatment has been described and the widespread use of acetylsalicylic acid (ASA) and clopidogrel requires clarification of the residual platelet reactivity (RPR). Various glycoprotein Ia (GpIa) polymorphisms have been investigated, but their influence on platelet reactivity in myocardial infarction (MI) patients undergoing percutaneous coronary intervention (PCI) on dual antiplatelet treatment is not still elucidated. Aim of this study was to evaluate the effect of C807T, G873A and T837C polymorphisms of GpIa on modulating platelet function in MI patients on dual antiplatelet treatment undergoing PCI. We measured platelet function by both a point-of-care assay (PFA100) and platelet-rich-plasma aggregation in 289 MI patients undergoing PCI and receiving dual antiplatelet treatment. Our data show that C807T/G873A polymorphisms, but not T837C, are associated with higher platelet reactivity. Carriers of the 807T/873A allele had significantly higher platelet aggregation values after arachidonic acid (AA) and collagen stimuli and, even if they did not reach the statistical significance, after 2 and 10 microM ADP stimuli; 807T/873A allele carriers had also significantly shorter closure times on PFA100/epinephrine membranes. At the multiple analyses, C807T/G873A polymorphisms resulted an independent risk factor for RPR defined by both AA induced platelet aggregation (OR=3.0, 95%CI 1.17-7.89, p=0.022) or by PFA100/epinephrine (OR=4.1, 95%CI 1.53-10.89, p=0.005). In conclusion, this study shows the 807T/873A allele of the GpIa gene is an independent risk factor for the RPR on dual antiplatelet treatment, and extends, in a larger acute coronary syndrome population, the observation that the 807T/873A allele is associated with higher platelet reactivity.

Adult↗
PubMed2006

A model of anti-angiogenesis: differential transcriptosome profiling of microvascular endothelial cells from diffuse systemic sclerosis patients.

The objective of this work was to identify genes involved in impaired angiogenesis by comparing the transcriptosomes of microvascular endothelial cells from normal subjects and patients affected by systemic sclerosis (SSc), as a unique human model disease characterized by insufficient angiogenesis. Total RNAs, prepared from skin endothelial cells of clinically healthy subjects and SSc patients affected by the diffuse form of the disease, were pooled, labeled with fluorochromes, and hybridized to 14,000 70 mer oligonucleotide microarrays. Genes were analyzed based on gene expression levels and categorized into different functional groups based on the description of the Gene Ontology (GO) consortium to identify statistically significant terms. Quantitative PCR was used to validate the array results. After data processing and application of the filtering criteria, the analyzable features numbered 6,724. About 3% of analyzable transcripts (199) were differentially expressed, 141 more abundantly and 58 less abundantly in SSc endothelial cells. Surprisingly, SSc endothelial cells over-express pro-angiogenic transcripts, but also show up-regulation of genes exerting a powerful negative control, and down-regulation of genes critical to cell migration and extracellular matrix-cytoskeleton coupling, all alterations that provide an impediment to correct angiogenesis. We also identified transcripts controlling haemostasis, inflammation, stimulus transduction, transcription, protein synthesis, and genome organization. An up-regulation of transcripts related to protein degradation and ubiquitination was observed in SSc endothelial cells. We have validated data on the main anti-angiogenesis-related genes by RT-PCR, western blotting, in vitro angiogenesis and immunohistochemistry. These observations indicate that microvascular endothelial cells of patients with SSc show abnormalities in a variety of genes that are able to account for defective angiogenesis.

Biopsy↗
PubMed2006

COL6A1 genomic deletions in Bethlem myopathy and Ullrich muscular dystrophy.

We have identified highly similar heterozygous COL6A1 genomic deletions, spanning from intron 8 to exon 13 or intron 13, in two patients with Ullrich congenital muscular dystrophy and the milder Bethlem myopathy. The 5' breakpoints of both deletions are located within a minisatellite in intron 8. The mutations cause in-frame deletions of 66 and 84 amino acids in the amino terminus of the triple-helical domain, leading to intracellular accumulation of mutant polypeptides and reduced extracellular collagen VI microfibrils. Our studies identify a deletion-prone region in COL6A1 and suggest that similar mutations can lead to congenital muscle disorders of different clinical severity.

Adult↗
PubMed2005

Using a calibration experiment to assess gene-specific information: full Bayesian and empirical Bayesian models for two-channel microarray data.

MOTIVATION: Microarray studies permit to quantify expression levels on a global scale by measuring transcript abundance of thousands of genes simultaneously. A difficulty when analysing expression measures is how to model variability for the whole set of genes. It is usually unrealistic to assume a common variance for each gene. Several approaches to model gene-specific variances are proposed. We take advantage of calibration experiments, in which the probes hybridized on the two channels come from the same population (self-self experiment). In this case it is possible to estimate the gene-specific variance, to be incorporated in comparative experiments on the same tissue, cellular line or species. RESULTS: We present two approaches to introduce prior information on gene-specific variability from a calibration experiment: an empirical Bayes model and a full Bayesian hierarchical model. We apply the methods in the analysis of human lipopolysaccharide-stimulated leukocyte experiments. AVAILABILITY: The calculations are implemented in WinBugs. The codes are available on request from the authors.

Algorithms↗
PubMed2005

A homozygous COL6A2 intron mutation causes in-frame triple-helical deletion and nonsense-mediated mRNA decay in a patient with Ullrich congenital muscular dystrophy.

Ullrich congenital muscular dystrophy (UCMD) is a severe disorder caused, in most cases, by a deficiency in collagen VI microfibrils. Recessive mutations in two of the three collagen VI genes, COL6A2 and COL6A3, have been identified in eight of the nine UCMD patients reported thus far. A heterozygous COL6A1 gene deletion, resulting in a mutant protein that exerts a dominant negative effect, has recently been described in a severely affected UCMD patient. Here we describe a patient in whom reverse transcription-PCR analysis of fibroblast RNA suggested a heterozygous in-frame deletion of exon 13 in the triple-helical domain of COL6A2, which is predicted to be dominantly acting. However, a homozygous A --> G mutation at -10 of intron 12 was found in the genomic DNA. The intron mutation activated numerous cryptic splice acceptor sites, generating normal and exon 13-deleted COL6A2 mRNA, and multiple aberrant transcripts containing frameshifts that were degraded through a nonsense-mediated decay mechanism. Northern analysis indicated diminished COL6A2 mRNA expression as the primary pathogenic mechanism in this UCMD patient. Our results underscore the importance of multifaceted analyses in the accurate molecular diagnosis and interpretation of genotype-phenotype correlations of UCMD.

Base Sequence↗
PubMed2005

Dominant and recessive COL6A1 mutations in Ullrich scleroatonic muscular dystrophy.

In this study, we characterized five Ullrich scleroatonic muscular dystrophy patients (two Italians, one Belgian, and two Turks) with a clinical phenotype showing different degrees of severity, all carrying mutations localized in COL6A1. We sequenced the three entire COL6 complementary DNA. Three of five patients have recessive mutations: two patients (P1and P3) have homozygous single-nucleotide deletions, one in exon 9 and one in exon 22; one patient (P2) has a homozygous single-nucleotide substitution leading to a premature termination codon in exon 31. The nonsense mutation of P2 also causes a partial skipping of exon 31 with the formation of a premature termination codon in exon 32 in 15% of the total COL6A1 messenger RNA. The remaining two patients carry a heterozygous glycine substitution in exons 9 and 10 inside the triple-helix region; both are dominant mutations because the missense mutations are absent in the DNA of their respective parents. As for the three homozygous recessive mutations, the apparently healthy consanguineous parents all carry a heterozygous mutated allele. Here, for the first time, we report a genotype-phenotype correlation demonstrating that heterozygous glycine substitutions in the triple-helix domain of COL6A1 are dominant and responsible for a milder Ullrich scleroatonic muscular dystrophy phenotype, and that recessive mutations in COL6A1 correlate with more severe clinical and biochemical Ullrich scleroatonic muscular dystrophy phenotypes.

Adolescent↗
PubMed2005

The antiangiogenic tissue kallikrein pattern of endothelial cells in systemic sclerosis.

OBJECTIVE: Postnatal angiogenesis relies on a proper response of endothelial cells to angiogenic stimuli. In systemic sclerosis (SSc), endothelial cells are unresponsive to angiogenic factors. Since circumstantial and experimental evidence points to tissue kallikreins as powerful effectors of the angiogenic response, we undertook this study to investigate the kallikrein pattern of normal and SSc endothelial cells in order to identify differences that can account for defective angiogenesis. METHODS: Expression of 14 tissue kallikreins was studied by a microarray approach, by reverse transcription-polymerase chain reaction, and by Western blotting in endothelial cells isolated from the skin of clinically healthy subjects and SSc patients. Cell proliferation was quantified by direct cell counting. Invasion and capillary morphogenesis were evaluated in a Boyden chamber and in culture flasks layered with Matrigel. Cyclic nucleotide production was measured by enzyme immunoassay. MAP kinase and ERK activation were measured by Western blotting. RESULTS: Endothelial cells from SSc patients showed poor expression of kallikreins 9, 11, and 12 compared with endothelial cells from normal subjects. Antibodies against the relevant kallikreins on normal endothelial cells revealed that while kallikreins 9, 11, and 12 induced cell growth, only kallikrein 12 regulated invasion and capillary morphogenesis. Buffering of kallikrein 12 with antibodies resulted in the acquisition of an SSc-like pattern by normal cells in in vitro angiogenesis. Reduction of cAMP and cGMP production and of ERK phosphorylation upon administration of antikallikrein antibodies revealed that the activity of kallikreins 9, 11, and 12 was mediated by kinins. CONCLUSION: Reduction of tissue kallikreins 9, 11, and 12 may be relevant to reduced angiogenesis in SSc patients.

Antibodies, Blocking↗
PubMed2005

Altered expression of the MCSP/NG2 chondroitin sulfate proteoglycan in collagen VI deficiency.

NG2, the rat homologue of the human melanoma chondroitin sulfate proteoglycan (MCSP), is a ligand for collagen VI (COL6). We have examined skeletal muscles of patients affected by Ullrich scleroatonic muscular dystrophy (UCMD), an inherited syndrome caused by COL6 genes mutations. A significant decrease of NG2 immunolabeling was found in UCMD myofibers, as well as in skeletal muscle and cornea of COL6 null-mice. In UCMD muscles, truncated NG2 core protein isoforms were detected. However, real-time RT-PCR analysis revealed marked increase in NG2 mRNA content in UCMD muscle compared to controls. We hypothesize that NG2 immunohistochemical and biochemical behavior may be compromised owing to the absence of its physiological ligand. MCSP/NG2 proteoglycan may be considered an important receptor mediating COL6-sarcolemma interactions, a relationship that is disrupted by the pathogenesis of UCMD muscle.

Animals↗
PubMed2005

High levels of homocysteine, lipoprotein (a) and plasminogen activator inhibitor-1 are present in patients with abdominal aortic aneurysm.

Over the last few years,there has been increasing interest in the investigation of the pathogenesis of AAA, and a role for some novel risk factors, in particular thrombophilic risk factors, has been suggested. The aim of this study was to evaluate a number of thrombophilic parameters in a large group of patients with AAA. In 438 patients with AAA, and in 438 healthy subjects, selected to be comparable for age and gender with patients and without instrumental evidence of AAA, a pattern of thrombophilic parameters [homocysteine (Hcy), lipoprotein (a) [Lp(a)], plasminogen activator inhibitor-1 (PAI-1), anticardiolipin antibodies (ACA), MTHFR C677T polymorphism, prothrombin gene G20210A variant and FactorV Leiden mutation] has been evaluated. A significant difference for Hcy, PAI-1 and Lp(a) plasma levels has been observed between patients and controls. After adjustment for the traditional cardiovascular risk factors, a significant increased risk of having AAA has been observed for high levels of Hcy (OR: 7.8; p<0.0001), Lp(a) (OR: 2.4; p<0.0001) and PAI-1 (OR: 3.2; p<0.0001). The association has been confirmed after exclusion of patients with other localization of atherosclerosis. Moreover, a significant association between larger abdominal aortic diameters and the number of thrombophilic parameters has been reported (r = 0.13; p = 0.005). In conclusion, a significant association between abnormal levels of some metabolic parameters related to thrombosis such as Hcy, Lp(a) and PAI-1 and AAA has been observed.

Adult↗
PubMed2004

Hyperhomocysteinemia and vitamin B6 deficiency: new risk markers for nonvalvular atrial fibrillation?

BACKGROUND: A recent "ex-vivo" study showed that nonvalvular atrial fibrillation (NVAF) is associated with enhanced activity of metalloproteinases at the atrial level, and in animal models homocysteine (Hcy) is able to activate metalloproteinases. The aim of this case-control study was to investigate the association of total Hcy plasma levels, vitamin status (folate, vitamin B6, and vitamin B12), and methylenetetrahydrofolate reductase C677T and CBS 844ins68 polymorphisms with NVAF. Furthermore, the role of these variables in the occurrence of ischemic events was investigated. METHODS: We studied 310 NVAF patients on oral anticoagulant treatment (168 patients with previous ischemic events and 142 without) and 310 controls. RESULTS: Hyperhomocysteinemia (highest quartile) and vitamin B6 deficiency (lowest quartile) were independently associated with NVAF after multivariate analysis (Hcy: odds ratio [OR] 6.40, 95% CI 3.29-12.46; vitamin B6: OR 3.02, 95% CI 1.02-8.95). A significant correlation was found between Hcy levels and left atrial diameter (r = 0.46; P <.001). As shown by multivariate analysis, elevated Hcy levels were an independent risk factor for ischemic complications during NVAF (OR 2.66, 95% CI 1.15-6.20). CONCLUSIONS: This study demonstrates a significant association of both elevated Hcy levels and low vitamin B6 levels with the presence of NVAF; in addition, it confirms the role of Hcy as a risk factor for ischemic events during NVAF.

Adult↗
PubMed2003

Increased plasma levels of lipoprotein(a) and the risk of idiopathic and recurrent venous thromboembolism.

PURPOSE: Elevated lipoprotein(a) [Lp(a)] levels are a recognized risk factor for cardiovascular disease; however, little is known about their effects on venous thromboembolism. METHODS: We conducted a case-control study of 603 adult patients with a history of venous thromboembolism (at least 6 months after the acute event) and 430 healthy subjects. We measured Lp(a), homocysteine, and antithrombin levels, factor V Leiden and factor II (prothrombin) polymorphisms, and anticardiolipin antibodies. RESULTS: Lp(a) levels >300 mg/L were found in 24% (n = 146) of the patients and in 13% (n = 58) of the controls (P = 0.005). In a multivariate analysis adjusted for acquired and hemostasis-related risk factors, there was an independent association between elevated (>300 mg/L) Lp(a) levels and venous thromboembolism (odds ratio = 2.1; 95% confidence interval: 1.4 to 3.2; P = 0.002). These results were confirmed in the 341 patients with idiopathic venous thromboembolism, as well as in those with recurrent thromboembolism. CONCLUSION: These results show that Lp(a) is an independent risk factor for venous thromboembolism in adults, suggesting that it may be involved in the pathogenesis of idiopathic and recurrent disease.

Adolescent↗
PubMed2003

Genetic determinants of fasting and post-methionine hyperhomocysteinemia in patients with retinal vein occlusion.

INTRODUCTION: Moderate hyperhomocysteinemia is considered a risk factor for both venous and arterial thrombosis. A prevalence of up to 30% of fasting hyperhomocysteinemia has been recently reported in patients with retinal vein occlusion (RVO) whereas conflicting data exist on the role of C677T polymorphism of the methylenetetrahydrofolate reductase (MTHFR) gene as a risk factor for RVO. No report has been published on cystathionine beta-synthase (CBS) 844ins68 polymorphism (another genetic determinant of blood Hcy levels) in RVO patients. Moreover, scarce information is available on the usefulness of measuring homocysteine also after methionine loading to increase the diagnostic efficacy of hyperhomocysteinemia in RVO patients. MATERIALS AND METHODS: In 55 consecutive patients with diagnosis of RVO and 65 matched controls, plasma fasting total homocysteine (Hcy) levels and CBS and MTHFR polymorphisms were evaluated. In patients with normal fasting Hcy levels, post-methionine Hcy levels were determined. RESULTS: Moderate fasting hyperhomocysteinemia was detected in 18/55 patients (32.7%). In the remaining 37 patients, Hcy was measured again post-methionine loading (PML). Only 3/37 (8.1%) patients had PML hyperhomocysteinemia. Thus, the total prevalence of moderate hyperhomocysteinemia in this cohort of RVO patients was 21/55 (38.2%). The prevalence of homozygosity for C677T MTHFR genotype, but not that of heterozygosity for CBS844ins68, was significantly higher in RVO patients than in controls. CONCLUSIONS: Differently from what has been reported for arterial and/or venous thrombosis, a single fasting Hcy measurement is able to detect most of RVO patients (85.7%) with moderate hyperhomocysteinemia. C677T MTHFR, but not CBS 844ins68, genotype may play a role as risk factor for RVO.

Adolescent↗
PubMed2003

Phenotypic variability of cardiovascular manifestations in Marfan Syndrome. Possible role of hyperhomocysteinemia and C677T MTHFR gene polymorphism.

AIMS: The aim of this study was to evaluate (1) homocysteinemia and the prevalence of the C677T MTHFR polymorphism in Marfan patients and (2) whether the severity of cardiovascular manifestations is associated with homocysteinemia and/or C677T polymorphism. METHODS AND RESULTS: We studied 107 patients subdivided into three subgroups based on the severity of cardiovascular manifestations: (A) no involvement (n=4); (B) mild involvement (n=45); (C) aortic dilatation or aortic dissection (n=58), and 189 controls. Total homocysteine (tHcy) was significantly higher in subgroup C than in subgroup B. In subgroup C patients with dissection tHcy was higher than in those without dissection. In subgroup C the prevalence of 677T homozygotes was higher, but not significantly, than in the subgroup B. In patients with dissection the prevalence of 677T homozygotes was significantly higher than in those without dissection and than in subgroup B. In the logistic regression analysis, severe cardiovascular manifestations and aortic dissection in Marfan patients were associated with tHcy plasma levels. CONCLUSIONS: Our data indicate an association between the severity of the cardiovascular manifestations, in particular aortic dissection, and elevated tHcy levels. This suggests an important role for tHcy in determining phenotypic variability in Marfan patients and provides further evidence for the association of homocysteinemia with the damage of the vascular system.

Adolescent↗
PubMed2003

Evaluation of a new point-of-care celite-activated clotting time analyzer in different clinical settings. The i-STAT celite-activated clotting time test.

BACKGROUND: Activated clotting time (ACT) is used to monitor heparin therapy during cardiopulmonary bypass, interventional cardiology, and hemodialysis. Traditionally, ACT is performed by use of the Hemochron system. Recently, a new device, the i-STAT system, has been introduced to measure ACT. The aim of this study was to correlate the performances of these two systems and to compare ACT values with heparin levels. METHODS: One hundred sixty-five samples from 29 patients undergoing cardiopulmonary bypass or hemodialysis were assayed in duplicate with two Hemochron and two i-STAT devices. Heparin levels were determined by anti-factor Xa assay. RESULTS: The Hemochron ACT ranged from 88 to 1,028 s, and the i-STAT ACT ranged from 80 to 786 s. Heparin plasma levels ranged from 0.01 to 10.8 U/mL. Bland-Altman analysis showed a mean difference between the two methods of 24 +/- 101 s. Strong relationships between anti-factor Xa activity and Hemochron ACTs (r2 = 0.69, P < 0.001) and i-STAT ACTs (r2 = 0.79, P < 0.001) were observed. During cardiac surgery, significant correlations were found: Hemochron, r2 = 0.61, P < 0.001 and i-STAT, r2 = 0.74, P < 0.001. During hemodialysis, relationships between anti-factor Xa activity and ACTs were found: Hemochron, r2 = 0.62, P < 0.001 and i-STAT, r2 = 0.55, P < 0.001. CONCLUSIONS: During cardiopulmonary bypass procedure and hemodialysis, i-STAT provides measurements of clotting time quite similar to Hemochron ACT, which were significantly correlated with heparin levels.

Aged↗
PubMed2002

Plasma and serum levels of D-dimer and their correlations with other hemostatic parameters in pregnancy.

The measurement of D-dimer in serum samples (s-DD) after standardized coagulation has been reported as a possible single global test for fibrinolysis in unstimulated conditions in healthy subjects and in patients with ischemic heart disease and with different metabolic disorders. No study has been performed on the use of this test in pregnancy, a condition characterized by physiological changes both in coagulation and in fibrinolysis. In this preliminary study, we have evaluated in 28 women with physiological pregnancy and in 23 comparable controls s-DD and a number of markers of coagulation and fibrinolysis. In nonpregnant women s-DD showed a good correlation with fibrinolytic parameters [euglobulin lysis time (ELT) and type 1 inhibitor of tissue plasminogen activator (PAI-1) act: P<.01; tissue plasminogen activator (t-PA) ag and PAI-1 ag: P<.05], confirming previous data, whereas in pregnant women no correlation was observed. Plasma DD (pls-DD) and s-DD levels were not correlated either in pregnant or in control women. s-DD levels were significantly higher than pls-DD in controls and in 15/28 pregnant women whose pls-DD values were in normal range or mildly increased (<110 ng/ml; P<.05), whereas in the 13 pregnant women with high pls-DD levels no significant differences were found between pls-DD and s-DD levels. Because in pregnancy high pls-DD levels are frequently found, possibly only as a consequence of enhanced clotting activation and fibrin deposition, we cannot exclude that D-dimer measured in serum reflects, at least in part, cross-linked fibrin degradation products (FDP) already present in blood before standardized coagulation. Therefore, D-dimer generated in vitro would account only in part for s-DD measured. This can explain why in pregnant women, differently from controls, s-DD does not correlate with fibrinolytic parameters. In conclusion, this preliminary study indicates that baseline pls-DD levels may be an important potential confounder in the interpretation of s-DD results in pregnant women and that s-DD cannot be proposed as a tool for a rapid evaluation of fibrinolytic activity in pregnancy.

Adult↗
PubMed2002

Novel COL6A1 splicing mutation in a family affected by mild Bethlem myopathy.

Bethlem myopathy is an early-onset benign myopathy characterized by proximal muscular weakness and multiple flexion contractures. It is a dominantly inherited disorder associated with mutations in the three COL6 genes encoding type VI collagen. We detected a g-->a substitution at +1 position of COL6A1 intron 3 in a four-generation Italian family affected by a mild form of Bethlem myopathy. The mutation results in the activation of a cryptic splice donor site at the 3' end of exon 3, leading to the loss of 66 nucleotides and an "in-frame" deletion of 22 amino acids in the NH2-domain. Molecular analysis on fibroblasts of the propositus showed that the mutated mRNA was present and stable, but the mutated protein could not be detected. Western blot and immunofluorescence analyses showed a decreased level of collagen VI synthesis and deposition in fibroblasts of the propositus. Together, the results suggest that the mutated protein was highly unstable and rapidly degraded, and that the mild phenotype was caused by a reduced amount of normal collagen VI microfibrils. In addition, we demonstrated that lymphocytes can be used for the first mutation screening analysis of patients with Bethlem myopathy.

Adolescent↗