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Biomedical subjects

V Piazza

Publications and source records attributed to V Piazza.

At least 19 recordsLinked to original sources
PubMed2005

Functional analysis of R75Q mutation in the gene coding for Connexin 26 identified in a family with nonsyndromic hearing loss.

Mutations in the gene (GJB2) coding for Connexin 26 (Cx26) are responsible for genetic forms of sensorineural hearing loss. This article describes a family characterized by congenital profound hearing loss, inherited in an autosomal dominant fashion and associated to a R75Q substitution in Cx26. Cell transfection and fluorescence imaging, dye transfer experiments and dual patch clamp recording showed that the mutant completely prevents the formation of functional channels despite assembling into junctional plaques, in communication incompetent HeLa cells. The disease is not associated with palmar and plantar keratosis in any of the family members, suggesting that R75Q substitution is not sufficient for the development of the complete syndromic phenotype. The association of palmar and plantar keratosis with profound hearing loss may be dependent on genetic background, requiring a functional interaction between the mutated Cx26 and other epidermally expressed connexins.

Connexin 26↗
PubMed2003

Involvement of acetyl choline in settlement of Balanus amphitrite.

The aim of the present study was to investigate the presence and distribution of cholinergic molecules in Balanus amphitrite cyprids and their possible involvement in settlement and adhesion. Acetylcholinesterase (AChE, the lythic enzyme of acetylcholine) activity was detected, for the first time, by biochemical and histoenzymological methods, in the thoracic muscles, gut wall and cement gland. The immunodetection of choline acetyltransferase-like (ChAT) molecules in the same area and in the neuropil of the central nervous system suggests the presence of a cholinergic innervation, and the involvement of acetylcholine in muscular contraction and cement gland exocytosis. The binding of FITC-conjugate alpha-bungarotoxin in the cement gland cells confirms the latter hypothesis. Acetylcholine involvement in the settlement process was also investigated by laboratory tests employing cholinergic antagonists and agonists. An increase of available acetylcholine due to the partial inhibition of AChE activity produced an increase in cyprid settlement. The data presented support the hypothesis that acetylcholine has a neurotransmitter/neuromodulator role in settlement and adhesion of barnacle cyprids.

Acetylcholine↗
PubMed1998

Dialysis hypersensitivity: a fading problem?

Allergic-type reactions experienced by patients on chronic hemodialysis are frequently reported in the literature, often related to compounds released during the hemodialysis sessions, in particular ethylene oxide (ETO). In these studies, dialysis patients seem to have higher values of IgE than those observed in a reference population. The aim of our work was to investigate IgE-related parameters of 126 dialysis patients in comparison with two control groups composed of healthy subjects and predialysis patients. IgE values were not significantly different in nonallergic dialysis patients, with a geometric mean (X) of 27.5 kU/l, when compared to healthy controls (X = 38 kU/l) and predialysis subjects (X = 40.7 kU/l). Higher values of IgE (X = 74.1 kU/l) were detected in allergic dialysis patients. However, only 3 patients, all without detectable antibodies against ETO, complained of anaphylactic symptoms during dialysis sessions in a 4-year surveillance period. At variance, 6 symptom-free patients carried IgE antibodies against ETO (range 0.7-15 kU/l), usually with high total IgE. Our results suggest a reduced frequency of hypersensitivity reactions during dialysis sessions. Furthermore, uremia does not alter IgE reactivity in the predialysis period or after long-term maintenance dialysis treatment.

Adult↗
PubMed1997

Use of statistical classifiers as support tools for the diagnosis of iron-deficiency anemia in patients on chronic hemodialysis.

Discriminant analysis, logistic regression and neural network models were applied to the diagnosis of iron-deficiency anemia in hemodialyzed patients. The ability of the three quantitative approaches to distinguish between subjects suffering or not from iron-deficiency anemia was compared by re-substitution and cross-validation testing. Methods performance was evaluated by means of sensitivity, specificity and accuracy. All the methods performed globally well (sensitivity and specificity > 0.85), revealing that the problem is classifiable. Neural networks showed the highest accuracy, both in the re-substitution (models developed and tested on the complete data set) and 3-way cross-validation (data set randomly splitted into 3 developmental and validation data sets) testing. These preliminary results suggest that the correct classification of iron status in the hemodialytic population can be treated as a pattern classification problem, for which neural networks and traditional statistical modelling can be a valuable aid to the clinical diagnosis of iron-deficiency anemia. A better performance of the neural network model must be confirmed through prospective testing on a larger data set.

Anemia, Iron-Deficiency↗
PubMed1997

[Three-dimensional transesophageal echocardiography: a new cardiologic diagnostic tool. Initial experience with 150 patients].

BACKGROUND: Three-dimensional transesophageal echocardiography is a new diagnostic tool and its potential has been investigated mainly in international centers dealing with research in the field of cardiac pathologies. The clinical usefulness and the potential additional information over multiplane transesophageal echocardiography in daily clinical practice have not been exstensively studied. OBJECTIVES: This study sought to assess the feasibility and to define the potential role of three-dimensional technique in a clinical cardiology department. POPULATION AND METHODS: One hundred-fifty patients (73 males, 77 females) aged 17-82 underwent a three-dimensional transesophageal echocardiographic study. Indications for the study were the following: 39 mitral (26%), 13 aortic (8%) and 4 tricuspidal (2%) valvulopathies, 23 valvular prostheses (15%), 6 aortic diseases (4%), 16 sources of embolism (10%), 16 congenital heart diseases (10%), 14 ischemic heart diseases (9.3%), 14 cardiomyopathies (9%), 5 other pathologies (3%). The 3 D examination quality was graded as insufficient, sufficient and good. The information obtained by "volume rendered" and "anyplane" three-dimensional echocardiography were compared with the traditional two-dimensional images to determine whether they provided additional information. RESULTS: A total of 288 acquisitions were obtained in the 150 patients (1.9 acquisitions per patient). Examinations were graded of good quality in 99 patients (61%), sufficient in 36 (24%) and insufficient in 15 patients (10%). Additional informations were obtained in 33 patients (22%) by "volume rendered" echocardiography and by "anyplane echocardiography", including mitral regurgitation or repair for valvular prolapse (11 patients), aortic valve malformations and endocarditis (4 patients), congenital heart diseases (9 patients), right ventricular dysplasia (6 patients) or hypertrophic cardiomyopathy (1 patient), tricuspid regurgitation (2 patients). The additional information were obtained in patients in the group of good 3 D reconstructions quality in all but two cases. CONCLUSIONS: The diagnostic use of the transesophageal technique with 3 D facilities permitted to obtain an overall 22% of additional information. These results will stimulate further study to evaluate the advantages of the three-dimensional technique in specific clinical fields of application.

Adolescent↗