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Biomedical subjects

F Bernardi

Publications and source records attributed to F Bernardi.

At least 109 records · Page 6Linked to original sources
PubMed1998

Geographic distribution of the 20210 G to A prothrombin variant.

A variant in prothrombin (clotting factor II), a G to A transition at nucleotide position 20210, has recently been shown to be associated with the prothrombin plasma levels and the risk of both venous and arterial thrombosis. The purpose of this study was to investigate the prevalence of carriership of this mutation in various populations. We combined data from 11 centres in nine countries, where tests for this mutation had been performed in groups representing the general population. We calculated an overall prevalence estimate, by a precision-weighted method, and, since the distribution of the prevalences did not appear homogeneous, by an unweighted average of the prevalences. We examined differences in the prevalences by geographical location and ethnic background as a possible explanation for the heterogeneity. Among a total of 5527 individuals who had been tested, 111 heterozygous carriers of the 20210A mutation were found. The prevalence estimates varied from 0.7 to 4.0 between the centres. The overall prevalence estimate was 2.0 percent (CI95 1.4-2.6%). The variation around the summary estimate appeared more than was expected by chance alone, and this heterogeneity could be explained by geographic differences. In southern Europe, the prevalence was 3.0 percent (CI95 2.3 to 3.7%), nearly twice as high as the prevalence in northern Europe (1.7%, CI95 1.3 to 2.2%). The prothrombin variant appeared very rare in individuals from Asian and African descent. The 20210A prothrombin variant is a common abnormality, with a prevalence of carriership between one and four percent. It is more common in southern than in northern Europe. Since this distribution within Europe is very different to that of another prothrombotic mutation (factor V Leiden or factor V R506Q), founder effects are the most likely explanation for the geographical distribution of both mutations.

Brazil↗
PubMed1998

Molecular bases of pseudo-homozygous APC resistance: the compound heterozygosity for FV R506Q and a FV null mutation results in the exclusive presence of FV Leiden molecules in plasma.

Pseudo-homozygous APC resistance, the condition resulting from compound heterozygosity for FV R506Q (FV Leiden) and quantitative FV deficiency, provides a natural model to study the interaction between procoagulant and anticoagulant defects. This paper reports a complete FV characterization of a pseudo-homozygous APC resistant thrombotic patient. The expression of the patient's non-Leiden gene was found to be severely impaired both at the mRNA and protein levels. In particular, only FV Leiden molecules were detected in the patient's plasma by immunoblotting, which accounts for the observed marked APC resistance. Analysis of the FV cDNA obtained by reverse transcription of platelet RNA revealed that the mRNA of the non-Leiden gene was extremely reduced in amount. A PAC clone containing the whole FV gene was used to design primers for a complete FV exon scanning. A 2-bp insertion at nucleotide 3706 in the large exon 13 of the non-Leiden gene, predicting a frame-shift and premature termination of protein synthesis, was identified as responsible for the FV defect. Failure to find any case of pseudo-homozygous APC resistance in a large sample (6,804) of blood donors suggests that this condition is extremely rare among normal controls and that its detection is favoured by the thrombotic risk that it may confer.

Aged↗
PubMed1998

Molecular and clinical aspects of factor VII deficiency.

Factor VII (FVII) plays an important role in the initiation of blood coagulation, forming a complex with tissue factor (TF) which activates FIX and FX and FVII zymogen. FVII deficiency displays considerable phenotypic and molecular heterogeneity and there are inconsistencies between the clinical picture observed and the underlying clotting and molecular defects. We have reviewed the data available in the literature on FVII-deficient patients. Clinically, cases range from asymptomatic to patients with severe haemorrhagic tendencies. Asymptomatic patients typically have FVII activity levels of >20% and are heterozygotes, double heterozygotes or homozygotes. Mild FVII-deficient patients, with FVII activity levels >2%, may be double heterozygotes or homozygotes for FVII gene missense mutations. Undetectable FVII levels in severely affected patients are often due to severe gene defects such as frameshifts or mutations affecting the splice sites. The analysis of structure-function relationships in FVII deficiency is difficult due to the complexity of the interactions involving FVII. Also, assays using different reagents may give different results with a given plasma sample, and are not very accurate at low levels of FVII which, although relatively low, may be clinically significant, adding complexity to the analysis of FVII deficiency. The sensitivity of our methods for phenotypic evaluation of FVII deficiency remains inadequate.

Factor VII Deficiency↗
PubMed1997

Several cytogenetic subclones may be identified within plasma cells from patients with monoclonal gammopathy of undetermined significance, both at diagnosis and during the indolent course of this condition.

Monoclonal gammopathy of undetermined significance (MGUS) is a frequent condition in patients over 50 years old, that ultimately leads to multiple myeloma (MM) in 20% of patients after 20 to 35 years of follow-up. Little is known about cytogenetic changes associated with this condition. We studied 19 MGUS patients both at diagnosis and after 12 to 35 months of follow-up (mean = 26), using DNA content measurement of bone marrow plasma cells (BMPC), and a new interphase fluorescence in situ hybridization technique (FISH) allowing the simultaneous identification of monotypic BMPC (fluorescent anti light-chain antibodies) and the determination of the number of copies for two different chromosomes within the same PC nucleus (one biotin-labeled probe coupled next to texas red avidin and one FITC-labeled probe). At diagnosis of the MGUS, single interphase FISH showed at least one numeric chromosome change in 13 of 19 patients, after the use of centromeric probes directed against chromosomes no. 3, no. 7, no. 9, and no. 11. At follow-up, abnormalities found at diagnosis in 13 patients were still shown. Moreover, abnormalities occurred in three of the last six patients (trisomy for one to three different chromosomes), although no patient evolved into MM. Dual interphase FISH showed that some BMPC bore numeric changes with both probes tested whereas other BMPC bore abnormality with only one of the probes tested. In patients who showed trisomy for at least three different chromosomes, distribution of numeric changes within BMPC defined significant numbers of up to seven different BMPC clones. All these various clones were shown both at diagnosis and at follow-up. In every patient, these various clones differed only for the number of abnormalities they exhibited, and could be related to each other in a model of gradual acquisition of chromosome changes. Eventually, data reported here show that MGUS patients acquire slowly, gradually, but ineluctably chromosome changes, distributed within several related subclones. However, these changes are not related to transformation into MM: among the various clones coexisting within the same patient, a peculiar change, still to demonstrate, might develop and lead to overt MM.

Adult↗
PubMed1997

A factor V genetic component differing from factor V R506Q contributes to the activated protein C resistance phenotype.

Factor V gene polymorphisms were investigated to detect components that may contribute to the activated protein C (APC) resistance phenotype in patients with venous thromboembolism. A specific factor V gene haplotype (HR2) was defined by six polymorphisms and its frequency was found to be similar in normal subjects coming from Italy (0.08), India (0.1), and Somalia (0.08), indicating that it was originated by ancestral mutational events. The relationship between the distribution of normalized APC ratios obtained with the functional assay and haplotype frequency was analyzed in patients heterozygous for factor V R506Q (factor V Leiden). The HR2 haplotype was significantly more frequent in patients with ratios below the 15th percentile than in those with higher ratios or in normal controls. Moreover, the study of 10 patients with APC resistance in the absence of the factor V R506Q mutation showed a 50-fold higher frequency of HR2 homozygotes. The HR2 haplotype was associated with significantly lower APC ratios both in patients with venous thromboembolism and in age- and sex-matched controls. However, the two groups showed similar HR2 haplotype frequencies. Plasma mixing experiments showed that an artificially created double heterozygote for the factor V R506Q mutation and the HR2 haplotype had an APC ratio lower than that expected for a simple R506Q heterozygote. Time-course experiments evaluating the decay of factor V in plasma showed the normal stability of the molecule encoded by the factor V gene marked by the HR2 haplotype, which ruled out the presence of a pseudo-homozygous APC resistance mechanism. Our results provide new insights into the presence of factor V genetic components other than the factor V R506Q that are able to contribute to the APC resistance phenotype in patients with venous thromboembolism.

Alleles↗
PubMed1997

Phenotypic homozygous activated protein C resistance associated with compound heterozygosity for Arg506Gln (factor V Leiden) and His1299Arg substitutions in factor V.

Two patients from two unrelated families with a history of thrombosis showed severe plasma activated protein C (APC) resistance. However, genotypic analysis demonstrated that the patients were heterozygous for factor V (FV) Leiden mutation. Coagulation studies revealed that FV clotting activity and antigen were similarly reduced at about 50% of normal in the patients. One brother of propositus A also showed the same abnormalities. Genetic analysis showed that, in addition to FV Leiden mutation in exon 10 of the FV gene (G1691A), these patients had a transition in exon 13 of the FV gene (A4070G; R2 allele) predicting His1299Arg substitution in the mature FV. Study by RT-PCR of platelet FV mRNA indicated that the mRNA produced by the FV gene, marked by the R2 allele, was reduced in amount in both pseudohomozygous patients of family A. The R2 allele has previously been demonstrated to be significantly associated with plasma FV deficiency in the Italian population. The presence of FV deficiency did not protect the propositi from thrombosis. These data confirm that genotypic analysis is mandatory in patients with phenotypic severe APC resistance before these patients are definitely classified as homozygotes for FV Leiden and that further genotypic analysis is advisable.

Adult↗
PubMed1997

Value of thyroid echography in the long-term follow-up of lithium-treated patients.

Psychiatric patients on long-term lithium (Li) therapy frequently develop goiter and/or hypothyroidism. It has also been suggested that Li may trigger/exacerbate thyroid autoimmunity. Previous studies provided evidence that underlying thyroid diseases represent important predisposing factors for the development of Li-induced thyroid dysfunction. The aim of the present paper was to assess the value of thyroid ultrasound-a simple and reliable tool to detect subtle thyroid abnormalities-in the longitudinal evaluation of 23 Li-treated psychiatric patients without evidence of biochemical thyroid abnormalities before therapy. For this purpose, thyroid ultrasound was associated with a clinical and laboratory (serum thyroxine, serum triiodothyronine, serum TSH, antithyroglobulin (AbTg), antithyroid microsomal (AbM) and antithyroid peroxidase autoantibodies) evaluation prior to and at 6- to 12-month intervals during Li treatment. On the basis of thyroid ultrasound before Li, patients were subdivided into two groups: group A (n = 15, 7 males, 8 females) with a normal echography and group B (n = 8, 5 males, 3 females) with mild ultrasound abnormalities. In group A the development of a small diffuse goiter was confirmed by physical examination during Li therapy; 2 patients displayed a transient increase of serum TSH concentration and none developed detectable serum antithyroid autoantibodies. Beside the small volumetric increase, no other ultrasound abnormalities were observed during the entire follow-up. In all group B patients a mild diffuse goiter was clinically detected before and on Li administration and no significant volumetric changes were observed during follow-up. Two patients developed high titers of AbM and AbTg 12 and 18 months after the beginning of Li, respectively; in 1 a persistent increase of serum TSH concentration was also observed. Thyroid echography before Li displayed different degrees of scattered or diffuse hypoechogenicity and a further decrease in echogenicity was detected during Li therapy in 2 patients. In conclusion, we provided further evidence that long-term Li administration is not associated with de novo appearance of thyroid autoimmune phenomena in humans, but rather with an exacerbation of underlying thyroid autoimmunity. In addition to thyroid autoantibody and TSH measurements, thyroid echography appears to be a sensitive tool in the identification of patients at risk of developing autoimmune hypothyroidism during long-term Li therapy.

Adult↗
PubMed1997

The heterozygous 20210 G/A prothrombin genotype is associated with early venous thrombosis in inherited thrombophilias and is not increased in frequency in artery disease.

A genetic variation in the 3'-untranslated region of the prothrombin mRNA (20210 G/A) has recently been reported to be associated with elevated plasma prothrombin levels and with an increased incidence of venous thrombosis. We determined the frequency of this mutation, the detection of which was improved by allele-specific amplification of exon 14 and by denaturing gradients (denaturing gradient gel electrophoresis), in cohorts of patients affected by venous thrombosis (n = 132) or by coronary or cerebrovascular diseases (n = 195) and in normal subjects from various populations. An overlapping frequency of the heterozygous genotype (4%) was found in normal subjects from Italy and Cyprus, and no carrier was detected in 40 subjects of Indian or Somali origin. The 20210 GA heterozygous genotype was not increased in frequency in patients with arterial disease. In contrast, the GA genotype was associated (P = .007) with venous thrombosis both in simple heterozygotes (16%) with a family history of thrombosis as well as in double heterozygotes (14%) for other known thrombophilic defects. A synergic interaction between the prothrombin 20210 GA genotype and the factor V Leiden mutation, both potentially affecting the prothrombinase complex, was suggested by the early onset of thrombosis (median age 22 years) in doubly heterozygous patients. The association of the 20210 A allele with higher prothrombin levels was confirmed in the Italian population. However, the prothrombin assay does not allow an efficient preselection of patients for the DNA analysis.

Adolescent↗
PubMed1997

Contribution of factor VII genotype to activated FVII levels. Differences in genotype frequencies between northern and southern European populations.

The relationship between coagulation factor VII (FVII) levels in plasma and FVII genotypes, determined by three polymorphisms (5'F7, IVS7, and 353R/Q), were studied in 500 control subjects enrolled in European multicenter study. The selection of particular FVII genotypes and the analysis of variance clearly indicated the independent contribution of a single 5'F7 insertion (A2) or 353Q (M2) allele to lowering plasma levels of activated FVII (FVIIa) (by a mean 25%). The M2 allele alone was found to make a major contribution to the genetically determined component of the FVIIa levels. Genotypes associated with low FVII levels were significantly rarer in the northern part of Europe (Oslo) than in the southern part (Rome, Murcia). The contribution made by the FVII genotype to the total variance of FVIIa levels was higher (30%) than that made to either FVII activity (25%) or FVII antigen (12%). Subjects with different FVII genotypes showed up to fivefold differences in mean FVIIa values, thus allowing attribution of a substantial part of the considerable interindividual variation to genetic variation, which may be of assistance in the interpretation of FVIIa levels on an individual basis. When FVII levels were adjusted by age and by triglyceride levels, the contribution of FVII genotypes to the FVII phenotypic variance was virtually unchanged. Taken together, these data indicate that in healthy control subjects the FVII genotype is a major predictor of plasma FVIIa levels and would support further study on the role of FVII genetic components in the development of cardiovascular disease.

Adult↗
PubMed1997

Hyperhomocyst(e)inemia and a common methylenetetrahydrofolate reductase mutation (Ala223Val MTHFR) in patients with inherited thrombophilic coagulation defects.

To assess whether certain abnormalities of the sulfated amino acid metabolism are associated with the occurrence of thromboembolic events in patients with inherited thrombophilic conditions, the levels of homocyst(e)ine, before or after methionine load, and the presence of the Ala223Val substitution in the 5,10-methylenetetrahydrofolate reductase (MTHFR) were evaluated in 119 subjects with a congenital single thrombophilic condition (type I deficiency of antithrombin n = 10, protein C n = 24, protein S n = 16; activated protein C resistance due to factor V Leiden mutation n = 69). Sixty-three subjects had experienced at least one documented thrombotic event, while the remaining 56 subjects were still free from any thrombotic symptom. Our results show that (1) high homocyst(e)ine levels, either in fasting condition or after methionine load, were not more frequent in subjects with inherited thrombophilic alterations (14.4%) than in normal control subjects (10% by definition) and (2) the frequency of hyperhomocyst(e)inemia was similar in thrombophilic subjects, who already have (14.3%) or have not (14.6%) experienced thrombotic events. As regards the MTHFR mutation, the homozygous condition was present in 23.2% of the thrombophilic patients versus 17.5% in the control subjects, a nonsignificant difference. The mutation was slightly more frequent in those thrombophilic subjects who had suffered a thrombotic episode (25.5%) versus those with no thrombosis (20.8%), with odds ratios of 1.61 (confidence interval (CI) = 0.58-4.52) and 1.24 (CI = 0.42-3.43), respectively. These differences were also nonsignificant. It is concluded that in subjects with inherited thrombophilias, a condition of hyperhomocyst(e)inemia "per se" is not a factor increasing the risk of thrombosis. The risk enhancement conferred by the MTHFR mutation, if any, seems to be slight or limited, and its significance could be ascertained only in a large multicenter trial.

Adult↗
PubMed1997

Hormonal replacement therapy affects calcitonin gene-related peptide and atrial natriuretic peptide secretion in postmenopausal women.

OBJECTIVE: Menopause is associated with critical changes in the cardiovascular system, and the possible effect of hormonal replacement therapy (HRT) on these changes is under investigation. The aim of our study was to evaluate in postmenopausal women the effects of HRT and clonidine on the response of plasma calcitonin gene-related peptide (CGRP) and plasma atrial natriuretic peptide (ANP) to the upright posture test and the saline infusion test respectively. METHODS: CGRP and ANP levels were measured with specific radioimmunological assays and expressed in pmol/l (means +/- S.E.M). DESIGN: Postmenopausal women (age 46-53 years) (n = 18) were studied before and after 3 months of HRT (n = 13) or clonidine treatment (n = 5). RESULTS: After HRT or clonidine treatment plasma CGRP levels (14.9 +/- 1.6 and 15.9 +/- 3.8 pmol/l) were significantly higher than before (9.8 +/- 0.6 and 10.5 +/- 1.6 pmol/l) (P < 0.01). The assumption of upright posture caused no change in plasma CGRP levels before treatment, while after HRT, but not after clonidine treatment, an increase in plasma CGRP levels was observed (P < 0.01 at 5 and 20 min). Basal plasma ANP levels significantly decreased after both HRT and clonidine treatment (P < 0.01). In untreated women the saline infusion test did not induce any change in plasma ANP levels; a significant response to the test was restored after HRT but not after clonidine treatment (P < 0.01 at 90 and 120 min). CONCLUSIONS: The results show that some of the adaptive responses modified by menopausal changes are restored by HRT but not clonidine treatment, suggesting a modulatory role for sex steroid hormones in cardiovascular function and salt and water balance.

Atrial Natriuretic Factor↗
PubMed1997

Non-secretory multiple myeloma with multinucleated giant plasma cells.

We report a case of non-secretory multiple myeloma with unusual cytological features. The plasma cells were multinucleated and contained up to forty nuclei. All nuclei had regular outlines without multilobulated and convoluted slopes. DNA content measurement demonstrated that all nuclei of uni- and multinucleated cells were diploid. All plasma cells contained cytoplasmic alpha chain but light chains and their corresponding transcripts were absent. There is no clear explanation concerning multinuclearity. In addition, hypotheses regarding non-secretion of immunoglobulin in non-secretory multiple myeloma and in other B-cell neoplasias are discussed.

Aged↗
PubMed1997

Involvement of peripheral blood cells in multiple myeloma: chromosome changes are the rule within circulating plasma cells but not within B lymphocytes.

The mononuclear cells in the peripheral blood are implicated in the myeloma process especially with the presence of peripheral blood plasma cells (PBPC) and clonal B lymphocytes found using phenotypic or gene rearrangement techniques. The purpose of this study was to look for aneuploidy in the two main B cell components of the peripheral blood: PBPC and CD20-positive B lymphocytes. Conventional cytogenetics (CC) or DNA content analysis and fluorescence in situ hybridization (FISH) with centromeric probes were performed on bone marrow plasma cells (BMPC) of 21 patients with multiple myeloma and peripheral blood cells were studied as follows: immunostaining to look for PBPC and to assess their number, image analysis cytometry for the determination of their DNA content, and FISH chromosomes analysis. FISH was performed using probes against the chromsomes that were lost or gained in BMPC and was coupled with immunostaining of the relevant light chain or CD20 antigen to study PBPC or B lymphocytes, respectively. Monotypic PBPC were found in 16 patients. Their DNA content was the same or nearly the same as for BMPC and they exhibited the same monosomies or trisomies as those found within their BM counterpart. By contrast, DNA content of mononuclear cells other than PBPC was within normal ranges, and in 13 of 15 patients CD20-positive B lymphocytes failed to show chromosomal changes by FISH analysis. In two patients however, a few CD20+ cells with lymphoid morphology exhibited chromosome changes, hypothesizing that a few cytogenetically abnormal B cells without plasmocytic morphology may circulate. From these data, we conclude that PBPC share the same genetic abnormalities as BMPC and thus belong to the malignant clone, whereas most peripheral blood B lymphocytes are unrelated to the tumor clone.

Aged↗
PubMed1997

New coagulation factor V gene polymorphisms define a single and infrequent haplotype underlying the factor V Leiden mutation in Mediterranean populations and Indians.

Two novel polymorphisms were identified in the factor V gene by direct sequencing of intronic areas. One of them, located in intron 9, is the marker closest to the Leiden mutation ever described, whereas the other, in intron 16, displays a rare allele invariantly associated to the mutation. Allele-specific amplification protocols were designed to perform extensive screenings for both polymorphic sites. The new markers were used in combination with six previously described polymorphisms to define specific factor V gene haplotypes. Haplotype investigations in 506Q homozygous thrombotic patients and normal controls showed the presence of a single haplotype underlying the factor V Leiden mutation in Mediterranean populations (among which Greek Cypriots, where the R506Q mutation is particularly frequent) and Indians. When traced in the absence of the Leiden mutation, the background haplotype was found to be present and roughly as frequent as the mutation itself in these populations. These findings indicate a single mutational event, that probably occurred outside Europe, as the cause of the Leiden mutation and provide a powerful tool to investigate its evolutionary history.

Cyprus↗
PubMed1996

Psychiatric disorder in a familial 15;18 translocation and sublocalization of myelin basic protein of 18q22.3.

Two related patients with similar clinical features consisting of a few dysmorphic signs and psychiatric disturbance were reported to have a partial trisomy of chromosomes 15(pter-q13.3) and 18(q23-qter) deriving from a familial translocation t(15;18). One patient is affected by bipolar disorder and the other by schizoaffective disorder. Both cases have a predominantly affective course; nevertheless, a clear diagnosis is difficult in the first patient, who is 15 years of age, and only a longitudinal course will allow us to establish a definite diagnosis. The possibility that these two pathologies belong to a single category is discussed, and the presence of a susceptibility locus on chromosome 18 is hypothesized. Cytogenetic data, FISH, and DNA studies indicate that the myelin basic protein (MPB) gene is not involved in the translocation, and localize it centromeric to the breakpoint on chromosome 18(q22.3). Thus, it is unlikely to be involved in the disease.

Adolescent↗
PubMed1996

Mutation pattern in clinically asymptomatic coagulation factor VII deficiency.

A total of 122 subjects, referred after presurgery screening or checkup for prolonged prothrombin time, were characterized for the presence of coagulation factor VII deficiency. Fourteen subjects carried a partial and asymptomatic deficiency, and in half of them dysfunctional molecules were detected in plasma. In nine subjects we found five missense mutations differing from those previously found in factor VII deficient patients. The others were homozygous for a common polymorphism (R353Q) that affects factor VII levels. A new codon dimorphism (A330) was also found in exon 8. Four mutations (R223W, M298I, R304Q, and R353Q) located at FVII-specific residues point out protein regions that are important for coagulation factor evolution, and two mutations (G342E and E265K) affect generic or partially generic residues. The newly reported mutations were combined with those we previously found, totalling 17 independent mutations responsible for FVII deficiency in 27 Italian pedigrees. We observed several similarities with the mutation pattern determined in factor IX, which include a high percentage of transitions at CpG doublets, the presence of hot spot sites affected by multiple substitutions, and of several topologically equivalent mutations.

Factor VII Deficiency↗