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Biomedical subjects

M Ambrosini

Publications and source records attributed to M Ambrosini.

At least 19 recordsLinked to original sources
PubMed2005

The use of a web-based interactive geographical information system for the surveillance of bluetongue in Italy.

Since 2000 Italy has experienced five epidemics of bluetongue, an arthropod-borne disease that affects primarily sheep and asymptomatically cattle, goats and wildlife ruminants. In four years the disease spread through Southern and Central Italy, involving 14 Italian regions out of 20. To control the disease, the Ministry of Health established a surveillance system that included clinical, entomological and serological surveillance elements. The National Reference Centre for Veterinary Epidemiology--Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise 'G. Caporale'--developed a Web-based National Information System (NIS) and a Geographical Information System (GIS)to collect and manage data from Veterinary Services across Italy. The system was designed to gather and spread information in order to support the management of control activities and to provide an early warning system. Surveillance data are displayed to the user in different ways: reports, tables and interactive maps.

Animals↗
PubMed1999

Regional distribution and cell type-specific expression of the mouse F3 axonal glycoprotein: a developmental study.

The expression of the mouse axonal adhesive glycoprotein F3 and of its mRNA was studied on sections of mouse cerebellar cortex, cerebral cortex, hippocampus, and olfactory bulb from postnatal days 0 (P0) to 30 (P30). In cerebellar cortex, a differential expression of F3 in granule versus Purkinje neurons was observed. F3 was highly expressed during migration of and initial axonal growth from cerebellar granule cells. The molecule was then downregulated on cell bodies and remained expressed, although at low levels, on their axonal extensions. On Purkinje cells, F3 was strongly expressed on cell bodies and processes at the beginning of the second postnatal week; by P16 it was restricted to neurites of Purkinje cells subpopulations. In the cerebral cortex, the molecule was highly expressed on migrating neurons at P0; by P16, it was found essentially within the neuropil with a diffuse pattern. In the hippocampal formation, where F3 was expressed on both pyramidal and granule neurons, a clear shift from the cell bodies to neurite extensions was observed on P3. In the olfactory pathway, F3 was expressed mainly on olfactory nerve fibers, mitral cells, and the synaptic glomeruli from P0 to P3, with a sharp decline from P11 to P16. As a whole, the data show that F3 protein expression is regulated at the regional, cellular, and subcellular levels and suggest that, in different regions, it can be proposed as a reliable neuronal differentiation marker.

Aging↗
PubMed1997

Functional organization of the promoter region of the mouse F3 axonal glycoprotein gene.

F3 is a developmentally regulated adhesive glycoprotein expressed by subpopulations of central and peripheral neurons which mediates neurite growth and fasciculation via cis- and trans-interactions with cell-surface or matrix components. We previously reported on the characterization of the F3 gene 5' flanking region in which we identified promoter and enhancer elements. Here, we report on the functional organization of the F3 gene regulatory regions. We show that the F3 promoter is built of linearly arranged positive and negative elements scattered through the 5' flanking region of the F3 gene and the 1st exon (exon 0). Neural- and cell type-specific expression of F3 appears to be governed by elements located in the most proximal promoter region which includes a neural-specific enhancer. In retardation assays, all these cis-acting elements bind nuclear proteins, three of which interact with the identified enhancer element while a single species interacts with sequences located within exon 0. Some of these proteins are also specifically expressed within the brain, indicating that they could correspond to neural-specific trans-acting factors. Elements located immediately upstream of the cell type-specific enhancer and within exon 0 are responsible for regulation of F3 expression by cAMP and retinoic acid.

Animals↗
PubMed1994

Detection of a conserved arrangement of three tRNA genes in the sunflower mitochondrial genome. Identification, mapping and expression of trnC-trnN-trnY genes.

The genes coding for tRNA-Cys (trnC), tRNA-Asn (trnN) and tRNA-Tyr (trnY) have been sequenced in a region of about 3.0 kb of the sunflower mitochondrial DNA. The trnC and trnY are genuine mitochondrial genes, while the trnN gene has a chloroplast origin. Despite their heterologous origin the three genes are transcribed. Their arrangement is the first detected in a highly conserved form in a specific group of advanced dicots.

Base Sequence↗
PubMed1992

[Foreign migrants in the labor force. The case of Lombardy].

"The article examines...the integration of immigrant workers into the regular labour force [in Italy]. The analysis concentrates its attention upon Lombardy, one of the regions in which the integration is more relevant. The author compares the situation in Milan, a metropolis where the tertiary sector is highly developed and job opportunities are very diversified, with the one in Brescia where immigrants are mainly employed as factory workers." (SUMMARY IN ENG AND FRE)

Acculturation↗
PubMed1991

[The transcatheter modulation of the AV node as a possible treatment of choice in nodal re-entrant tachycardia].

Transcatheter modification of the AV node with radiofrequency energy (RF) was performed in 6 patients (mean age 24 years) with inducible AV node reentry tachycardia (AVNRT). Although tachycardia could be controlled with antiarrhythmic drugs in each patient, the option was offered to eliminate the arrhythmia by means of RF catheter technique. A 7F catheter with 2 mm interelectrode distance and a large tip electrode was positioned to record the maximal His deflection, then withdrawn until the smallest possible His and ventricular potentials with a large atrial signal could be recorded. RF energy was delivered at this site in unipolar mode in incremental steps, until AVNRT was no longer inducible or VA block occurred. The procedure resulted in non-inducibility of tachycardia in 5/6 patients. The fast and the slow pathways were abolished in 2 and 1 patients, respectively, while the AV node duality persisted in 2 in spite of non-inducibility. VA block occurred in 2 patients, while the anterograde conduction was preserved in all. During the follow-up (mean 4.5 months) 5/6 patients remained free of AVNRT without drugs. It is concluded that transcatheter RF modulation of the AV node can be advised, provided that similar results will be obtained in larger series with longer follow-up, as the first line therapy in patients with AVNRT.

Adolescent↗
PubMed1991

[The disappearance of the circadian rhythm of the heart rate in heart transplantation in the presence of acute rejection].

The present study is aimed to investigate the circadian rhythm (CR) of heart rate (HR) in acute rejecting and non-rejecting heart transplanted patients (HTP). The purpose is to provide evidence that an impairment in the HR CR may have a role in predicting episodes of acute rejection in HTP. The study was carried out on 32 Holter monitorings of 13 patients: 9 Holter monitorings were carried out during an episode of acute rejection documented by endomyocardial biopsy. Time data series were analyzed by Cosinor method in order to validate the occurrence of HR CR. The Cosinor analysis found a highly statistically significant HR CR in non-rejecting HTP. The occurrence of the HR CR was not statistically validated in acute rejecting HTP. These findings suggest that the lack of a periodic variability in the 24-hour HR pattern may be useful to diagnose acute heart rejection.

Acute Disease↗
PubMed1991

[The transcatheter ablation of arrhythmias].

The introduction of transcatheter ablation techniques has opened a new era of the management of tachyarrhythmias. The rationale of these therapeutic procedures lies in the induction of an irreversible and limited damage to cardiac tissue involved in arrhythmias. In its original form, the technique involves the delivery of high energy DC discharges (fulguration) to the target area through a temporary catheter electrode. A primary drawback of fulguration, when used for ablation of AV node-His bundle, is the induction of a pacemaker-dependent state; the barotraumatic effect that results from high energy impulses constitutes the major limitation in the case of ablation of accessory pathways or arrhythmogenic areas. Recently, the efficiency of the procedure has been substantially improved by the use of low-power, high-frequency alternating current (radiofrequency), that allows to deliver graded amounts of disrupting energy to selected areas while avoiding undesirable biophysical effects to the surrounding tissue. Remarkable results, with a success rate close to 100%, are reported with radiofrequency ablation of AV node reentry tachycardia, as well as reciprocating tachycardia associated with the preexcitation syndrome, so that this technique can be considered the procedure of choice for both categories of patients. Catheter modification of AV conduction provides a therapeutic tool for treating atrial tachyarrhythmias with rapid ventricular responses. In such cases, however, the risk of AV block with the need for pacemaker implantation must be taken into account. Results of catheter ablation of ventricular tachycardia have been inconstant and generally disappointing, except for ventricular tachycardias due to reentry in the His-Purkinje system, for which a high success rate is reported. Experience with radiofrequency ablation in ventricular tachycardia is very limited, but localization of a critical segment of reentry could improve the efficiency of this technique.

Arrhythmias, Cardiac↗
PubMed1990

[Fulguration of the bundle of His. Description of 3 new cases].

With the purpose to call attention to the clinical utility of fulguration of the His bundle (a therapeutic procedure somewhat neglected in Italy) 3 new cases are presented. All patients had a long history of supraventricular tachyarrhythmias refractory to conventional treatment. Patients 1 and 2, in whom surgical correction of tetralogy of Fallot and mitral valve replacement, respectively, had been performed several years before, had chronic atrial tachycardia with congestive heart failure. Patient 3 suffered from persistent atrial flutter, in the absence of demonstrable organic heart disease. Three shocks of 320 J were necessary to induce complete AV block in patient 1 and 2. In patient 3, a single discharge (320 J) resulted in interruption of AV conduction. Twenty-four hours after the procedure, a rate-responsive ventricular pacemaker was implanted in all patients. The success of the procedure was confirmed 3 months later, during transitory pacemaker inhibition. Patients 1 and 3 exhibited atrial tachycardia and atrial flutter, respectively, but complete AV block was still present, with junctional escape rhythm at a rate of 40 and 45 b/min; in patient 2 atrial tachycardia with high degree AV block, and a mean ventricular rate of 75 b/min, were observed. Refinement of transcatheter ablative techniques is desirable. However, even in the present status, catheter ablation of the His bundle is an effective, low-risk procedure for patients with refractory supraventricular tachyarrhythmias.

Adult↗