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Biomedical subjects

V Riccardi

Publications and source records attributed to V Riccardi.

14 recordsLinked to original sources
PubMed2006

An absence of cutaneous neurofibromas associated with a 3-bp inframe deletion in exon 17 of the NF1 gene (c.2970-2972 delAAT): evidence of a clinically significant NF1 genotype-phenotype correlation.

Neurofibromatosis type 1 (NF1) is characterized by cafe-au-lait spots, skinfold freckling, and cutaneous neurofibromas. No obvious relationships between small mutations (<20 bp) of the NF1 gene and a specific phenotype have previously been demonstrated, which suggests that interaction with either unlinked modifying genes and/or the normal NF1 allele may be involved in the development of the particular clinical features associated with NF1. We identified 21 unrelated probands with NF1 (14 familial and 7 sporadic cases) who were all found to have the same c.2970-2972 delAAT (p.990delM) mutation but no cutaneous neurofibromas or clinically obvious plexiform neurofibromas. Molecular analysis identified the same 3-bp inframe deletion (c.2970-2972 delAAT) in exon 17 of the NF1 gene in all affected subjects. The Delta AAT mutation is predicted to result in the loss of one of two adjacent methionines (codon 991 or 992) ( Delta Met991), in conjunction with silent ACA-->ACG change of codon 990. These two methionine residues are located in a highly conserved region of neurofibromin and are expected, therefore, to have a functional role in the protein. Our data represent results from the first study to correlate a specific small mutation of the NF1 gene to the expression of a particular clinical phenotype. The biological mechanism that relates this specific mutation to the suppression of cutaneous neurofibroma development is unknown.

Adolescent↗
PubMed1994

[Do our patients follow the clinical indications prescribed after coronary angiography?].

BACKGROUND: Aim of the study is to evaluate patients compliance with therapeutic recommendations after coronary angiography. METHODS: We analyzed all patients who underwent coronary angiography in an university center during 1990. One of the following treatments were recommended: medical therapy without revascularization, percutaneous transluminal coronary angioplasty, coronary artery bypass grafting. A cohort of 392 patients was assessed one year after coronary angiography in order to evaluate clinical predictors of non compliance with the treatment recommended. RESULTS: Of the 141 patients, for whom medical treatment was recommended, 16 (11%: 95% confidence interval 6-17%) had revascularization. By stepwise discriminant regression analysis, older age, congestive heart failure and critical lesion of the left anterior descending artery were statistically significant predictors of non compliance. Of the 137 patients, for whom PTCA was recommended, 8 (6%: 2-9%) were non compliant. No variables were predictive of non compliance. Of the 114 patients, for whom CABG was recommended, 15 (13%: 7-19%) were non compliant. By stepwise regression analysis, absence of typical angina was predictive of non compliance. For 12 patients non compliance was related to personal preferences, for 10 to clinical deterioration, for 9 to a second opinion, and 3 were still in the surgical waiting list one year after coronary angiography. One year mortality was not affected by non compliance. CONCLUSIONS: Non compliance to recommended treatment after coronary angiography is uncommon and is mainly related to patients preference towards a less invasive treatment or to a change of clinical conditions over time.

Aged↗
PubMed1989

Type 1 neurofibromatosis: selective expression of extracellular matrix genes by Schwann cells, perineurial cells, and fibroblasts in mixed cultures.

Cutaneous neurofibromas, characteristic lesions of neurofibromatosis 1, are composed of an abundant extracellular matrix and nerve connective tissue-derived cell types: Schwann cells, perineurial cells, and fibroblasts. In this study, the extracellular matrix gene expression by these cells was examined under culture conditions that allowed them to be metabolically active and readily identifiable by morphologic and immunocytochemical criteria. Northern hybridizations demonstrated expression of genes for type I, III, IV, and VI collagens, as well as for fibronectin, laminin, and elastin. In situ hybridizations revealed that all three cell types expressed pro alpha 1 (I), pro alpha 2 (VI), and laminin B1 chain genes. However, fibroblasts did not contain [35S]cDNA-mRNA hybrids specific for type IV collagen, whereas both Schwann cells and perineurial cells expressed these genes. Perineurial cells and fibroblasts readily expressed the fibronectin gene whereas Schwann cells were essentially devoid of the corresponding mRNA. Perineurial cells also expressed the gene for laminin A chain. The results indicate that the extracellular matrix gene expression profiles of Schwann cells, perineurial cells, and fibroblasts are distinct: all three cell types are capable of expressing some of the genes for extracellular matrix components, such as type I and VI collagens, whereas Schwann cells and perineurial cells may have the primary role in synthesizing basement membrane zone components, type IV collagen and laminin. These observations potentially relate to the mechanisms of growth and development of human neurofibromas. The results attest to the applicability of the methodology utilized here to study other human tumors with mixed cell populations.

Blotting, Northern↗
PubMed1987

Nonrandom loss of maternal chromosome 11 alleles in Wilms tumors.

A series of gene probes for chromosome 11 has been used to study the genetic events associated with the development of Wilms tumor. Examination of DNA samples from five patients with Wilms tumor in whom the tumors showed loss of chromosome 11 alleles and their parents indicate that alleles lost in the tumors are of maternal origin. These data suggest that the parental derivation of chromosome 11 alleles lost in these Wilms tumors is not random.

Alleles↗
PubMed1987

Neurofibromatosis.

Neurofibromatosis (NF) is an inherited disorder characterized by the development of a wide variety of clinical manifestations, including characteristic "freckle-like" pigmentations (cafe au lait spots) that develop in infancy, followed by skin tumors that may vary widely in size, number, and distribution. In addition to skin tumors, bone, neurologic, and endocrine abnormalities are common. NF is recognized in eight different types, with clinical heterogeneity being the hallmark of this disease. Malignant degeneration of the tumor to neurofibrosarcoma is rare. Early diagnosis, genetic counseling, treatment of symptoms, and appropriate surgery are the tools available for management of NF patients. Surgical procedures generally involve judicious subtotal resection, combined with reconstructive efforts aimed at functional improvement and cosmesis.

Adult↗
PubMed1986

The French-American-British (FAB) classification of leukemia. The Pediatric Oncology Group experience with lymphocytic leukemia.

The Pediatric Oncology Group institutions initiated extensive subclassification of cases of acute lymphocytic leukemia (ALL) at diagnosis into laboratory-designated categories. Included was a French-American-British (FAB) classification of all new patients, which was reviewed by a central six-member committee. In addition, on the basis of immunologic criteria, patients were defined as having T-, B-, pre-B-, or "null" cell leukemia. Slides from 617 patients were reviewed. Five hundred forty-six (88.5%) were classified as L1, 51 (8.3%) were classified as L2, 9 (1.5%) were classified as L3, and the remainder could not be assigned. Concordance within the committee was good: in 71% of the cases the committee was unanimous, and in an additional 17% only one member disagreed. In only 11 cases (1.8%) was diagreement such that a majority classification could not be assigned. Institutions assigned L2 more frequently. There was a strong correlation with L3 for B-cell disease only. However, four patients had unequivocal B-cell disease and unmistakable L1 morphologic type, whereas one and had L3 morphologic features and had non-B-cell disease. There was no correlation between the other immunologic markers or periodic acid-Schiff stain and FAB classification, nor between L1 or L2 and risk factors. However, for the 248 null cell and pre-B-cell patients, L2 was more frequent among patients in the poor-risk group (P = 0.008). The time to first failure was significantly shorter for patients with L3 morphologic type. The induction failure rate of L2 patients was significantly greater than that of L1 patients (P = 0.016). With analysis of the duration of remission and adjustment for risk factors, the impact of L2 morphologic characteristics on outcome was not significant (P = 0.18) in null cell patients. Even unadjusted for risk factors, there was no impact of L2 morphologic type on outcome in the pre-B-cell phenotype. It can be concluded that other risk factors overshadow the impact of L1 and L2 morphologic features in predicting duration of remission.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1985

A discordant sibship analysis between beta-NGF and neurofibromatosis.

A new restriction fragment length polymorphism 5' to the beta-nerve growth factor (beta-NGF) gene has been found in proximity to the BglII polymorphism, and both polymorphisms are detectable with an EcoRI 7-kilobase (kb) subclone. Absence of the TaqI recognition site lengthens the 4.3-kb and 1.7-kb hybridizing fragments to 6 kb, and the alleles are in Hardy-Weinberg equilibrium with frequencies of 83% and 17%, respectively. Previous research has suggested that NGF is involved in disseminated neurofibromatosis (NF). We found four informative disseminated NF families with the two beta-NGF polymorphisms and have provided clearcut evidence against beta-NGF gene alteration in these families. If disseminated NF is found to be heterogeneous at a molecular level, more families should be tested to further rule out any role for beta-NGF in this syndrome.

Base Sequence↗