Browsing by Author "Silveira, I."
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- Complexo de Von Meyenburg ou Metástases Hepáticas? Caso Clínico e Revisão da LiteraturaPublication . Silveira, I.; Mota, F.; Ferreira, J.; Dias, R.; Leuschner, P.Hepatic lesions represent a common finding in clinical practice. Bile ducts hamartomas, also known as Von Meyenburg complex, are benign hepatic malformations composed of small dilated cystic bile ducts lined by fibrous stroma. They represent a rare and asymptomatic clinic-pathological entity. Imagiological findings are variable, and may present as multiple small scattered lesions, or rarely as a single nodule. These findings may resemble secondary lesions and, although benign, there are cases of progression to colangiocarcinoma. Thus it is important to include this complex in the differential diagnoses of focal hepatic lesions, being necessary a detailed investigation for their differentiation. This case represents an atypical presentation of a rare and not frequently considered entity in clinical practice
- Efficacy And Safety Of Implantable Loop Recorder: Experience Of A CenterPublication . Silveira, I.; Sousa, M.; Antunes, N.; Silva, V.; Roque, C.; Pinheiro-Vieira, A.; Lagarto, V.; Hipólito-Reis, A.; Luz, A.; Torres, S.Introduction: Symptoms like syncope or palpitations frequently present a diagnostic challenge. An implantable loop recorder (ILR) is an important aid in the management of these patients. Methods: A retrospective study of patients that underwent ILR implantation from November 2007 to 2014. For each patient the indication for implantation, baseline characteristics, previous study, complications, recorded tracing and interventions were evaluated. Results: A total of 62 patients were included, 50% men, with a mean age of 62.5±18.8 years old. Previously to ILR implantation 88.7% of patients had performed Holter, 17.7% external events recorder, 33.9% Tilt test and 29% an electrophysiological study. The implantation indications were recurrent syncope in 90.3%, palpitations 8.1% and ischemic stroke in one patient. Mean follow-up time was 17.1±16.3 months. Symptoms were reported in 66.1% of the patients, 46.8% of those yielding a diagnostic finding. In all cases of palpitation complaints with diagnosis we found atrial fibrillation (AF). In patients with syncope atrioventricular conduction disturbance was demonstrated in 19.6%, sinus node dysfunction in 16.1%, paroxysmal supra-ventricular tachycardia 7.1% and AF in 1.8%. These finding resulted in 19 pacemaker and one CRT-D implantation, introduction of anticoagulation in five patients and one ablation of accessory pathway. There were no major complications. Conclusion: ILR proved to be safe and efficient. It has enabled the identification or exclusion of serious rhythm disturbances in more than half of patients and provided a targeted therapeutic intervention.
- High germinal instability of the (CTG)n at the SCA8 locus of both expanded and normal allelesPublication . Silveira, I.; Afonso, I.; Guimarães, L.; Mendonça, P.; Santos, C.; Maciel, P.; Matos, J.; Costa, M.; Barbot, C.; Tuna, A.; Barros, J.; Jardim, L.; Coutinho, P.; Sequeiros, J.Abstract The autosomal dominant spinocerebellar ataxias (SCAs) are a group of late-onset, neurodegenerative disorders for which 10 loci have been mapped (SCA1, SCA2, SCA4-SCA8, SCA10, MJD, and DRPLA). The mutant proteins have shown an expanded polyglutamine tract in SCA1, SCA2, MJD/SCA3, SCA6, SCA7, and DRPLA; a glycine-to-arginine substitution was found in SCA6 as well. Recently, an untranslated (CTG)n expansion on chromosome 13q was described as being the cause of SCA8. We have now (1) assessed the repeat size in a group of patients with ataxia and a large number of controls, (2) examined the intergenerational transmission of the repeat, and (3) estimated the instability of repeat size in the sperm of one patient and two healthy controls. Normal SCA8 chromosomes showed an apparently trimodal distribution, with classes of small (15-21 CTGs), intermediate (22-37 CTGs), and large (40-91 CTGs) alleles; large alleles accounted for only0.7% of all normal-size alleles. No expanded alleles (>/=100 CTGs) were found in controls. Expansion of the CTG tract was found in five families with ataxia; expanded alleles (all paternally transmitted) were characterized mostly by repeat-size contraction. There was a high germinal instability of both expanded and normal alleles: in one patient, the expanded allele (152 CTGs) had mostly contraction in size (often into the normal range); in the sperm of two normal controls, contractions were also more frequent, but occasional expansions into the upper limit of the normal size range were also seen. In conclusion, our results show (1) no overlapping between control (15-91) and pathogenic (100-152) alleles and (2) a high instability in spermatogenesis (both for expanded and normal alleles), suggesting a high mutational rate at the SCA8 locus.
- Partial Papillary Muscle Rupture after Myocardial Infarction and Early Severe Obstructive Bioprosthetic Valve Thrombosis: an Unusual CombinationPublication . Silveira, I.; Oliveira, M.; Gomes, C.; Cabral, S.; Luz, A.; Torres, S.Mechanical complications after myocardial infarction (MI) have become uncommon since the introduction of primary angioplasty. They can lead to a rapid clinical deterioration and a fatal outcome, with patient’s survival being dependent on their prompt recognition and intervention. We describe a case of two rare mechanical complications: a partial papillary muscle rupture after MI, followed by an early severe obstructive thrombosis of the implanted bioprosthetic valve.
- Phenotypes of spinocerebellar ataxia type 6 and familial hemiplegic migraine caused by a unique CACNA1A missense mutation in patients from a large familyPublication . Alonso, I.; Barros, J.; Tuna, A.; Coelho, J.; Sequeira, J.; Silveira, I.; Coutinho, P.Background: Different mutations in the 1A-subunit of the brain P/Q-type calcium channel gene (CACNA1A) are responsible for familial hemiplegic migraine (FHM), episodic ataxia type 2, and spinocerebellar ataxia type 6 (SCA6). Missense and splice site mutations have been found in FHM and episodic ataxia type 2, respectively, whereas a CAG repeat in the CACNA1A gene was found expanded in patients with SCA6. Objective: To identify the disease causing mutation in a large family of patients with phenotypes of hemiplegic migraine with or without cerebellar signs or permanent cerebellar ataxia without migraine inherited in a dominant manner. Patients and Methods: We examined 15 patients from a large family identified through a systematic survey of hereditary ataxias being conducted in Portugal. Linkage analysis was performed with CACNA1A gene markers, and mutation analysis was performed by single strand conformational polymorphism analysis and sequencing. Results: Genetic linkage analysis with CACNA1A intragenic markers showed positive LOD scores. The maximal LOD score was obtained with the polymorphic CAG repeat (Zmax=4.47, =0). By single-strand conformational polymorphism analysis, a shift in exon 13 of the CACNA1A gene was detected in all patients.AG-to-A substitution was then identified, resulting in an arginine-to-glutamine change at codon 583 of this calcium channel 1A-subunit. Conclusions: The disease-causing mutation in this family was identified, showing that a unique mutation in the CACNA1A gene causes several phenotypes, including those of SCA6 and FHM, thus suggesting that SCA6 and FHM are not only allelic diseases but are the same disorder with a large phenotypic variability.