Browsing by Author "Lopes, R"
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- Animal Models of Acute Gastric Mucosal Injury: Macroscopic and Microscopic EvaluationPublication . Simões, S; Lopes, R; Dias Campos, MC; Marruz, MJ; Meirinhos da Cruz, ME; Corvo, LAcute gastric mucosal injury is a common disorder of the gastrointestinal tract and the search for new therapeutics is ongoing. The aim of this study is to update and expand the information related to the most widely used rat models of acute gastric ulcer, the ethanol-induced ulcer and the indomethacin-induced ulcer. These two models are compared in terms of macroscopic and microscopic features. Experimentally, ethanol was given orally in a single dose and indomethacin was subcutaneously injected into male Wistar rats. After ulcerative challenges, the stomachs were removed and visually inspected. Anti-ulcerative drugs were used to validate the models. Histological analysis of the stomachs determined the microscopic score. The methodology used for model evaluation applied to macroscopic and microscopic gastric lesions. With these methods it was possible to induce lesions in the gastric mucosa. Microscopic evaluation permitted assessment of the inflammatory and apoptotic impact in the mucosa not observable by macroscopic evaluation. Groups of animals were treated with two standard drugs: sulcralfate suspension or lansoprazole solution. Both drugs reduced macroscopic and microscopic lesions, particularly the hemorrhagic ones. Both models induced acute gastric mucosal injury and no single evaluation method can address all the aspects of the pathology of gastric lesions. As a complement to macroscopic evaluation, microscopy appears to be a relevant tool to selectively identify specific aspects of the development of mucosal injury, quantify the extent of lesions, and contribute to an appropriate interpretation of results. The score systems established here offer a reliable method for testing antiulcer drugs.
- Cor Triatriatum num Adulto Assintomático. Diagnóstico por AngioTC CardíacaPublication . Ferreira, F; Ferreira, AM; Lopes, R; Ferreira, J; Correia, MG; Gil, VM
- Dynamics of Epileptic Activity in a Peculiar Case of Childhood Absence Epilepsy and Correlation with Thalamic Levels of GABAPublication . Leal, A; Vieira, JP; Lopes, R; Nunes, R; Gonçalves, S; Lopes da Silva, F; Figueiredo, PChildhood absence epilepsy (CAE) is a syndrome with well-defined electroclinical features but unknown pathological basis. An increased thalamic tonic GABA inhibition has recently been discovered on animal models (Cope et al., 2009), but its relevance for human CAE is unproven. METHODS: We studied an 11-year-old boy, presenting the typical clinical features of CAE, but spike-wave discharges (SWD) restricted to one hemisphere. RESULTS: High-resolution EEG failed to demonstrate independent contralateral hemisphere epileptic activity. Consistently, simultaneous EEG-fMRI revealed the typical thalamic BOLD activation, associated with caudate and default mode network deactivation, but restricted to the hemisphere with SWD. Cortical BOLD activations were localized on the ipsilateral pars transverse. Magnetic resonance spectroscopy, using MEGA-PRESS, showed that the GABA/creatine ratio was 2.6 times higher in the hemisphere with SWD than in the unaffected one, reflecting a higher GABA concentration. Similar comparisons for the patient's occipital cortex and thalamus of a healthy volunteer yielded asymmetries below 25%. SIGNIFICANCE: In a clinical case of CAE with EEG and fMRI-BOLD manifestations restricted to one hemisphere, we found an associated increase in thalamic GABA concentration consistent with a role for this abnormality in human CAE.
- Gynecological History Up to Diagnosis and Pregnancy Outcomes in Diagnosed Wilson's Disease Under Therapy - a Bicentric Matched Control Cohort StudyPublication . Roseira, J; Lopes, R; Silva, MJ; Vieira, AM; Sampaio, M; Calinas, FIntroduction: most studies narrowly focus on pregnancy outcome comparisons between Wilson’s disease (WD) patients on and off treatment. We aimed to identify menses irregularities in untreated WD, and to evaluate pregnancy outcomes in treated WD patients as compared to matched controls (with and without liver disease). Methods: females with WD, hepatitis C (liver disease controls), and other gastrointestinal conditions (controls without liver disease) were identified at two tertiary hospital gastroenterology departments. Gynecological and obstetric data were retrospectively collected. A comparison of gynecological and obstetric outcomes was performed between the groups, and regression models were used to further assess obstetric outcomes. Results: a total of 18 females with WD were identified, comprising 19 pregnancies under treatment in 11 patients, and 20 females were included in each control group. Age and liver disease stage were adjusted between groups. The incidence of menses irregularities was higher for WD (late menarche, 83 % vs. 10 % vs. 10 %, p < 0.01; irregular cycles, 100 % vs. 20 % vs. 20 %, p < 0.01; amenorrhea, 67 % vs. 10 % vs. 5 %, p < 0.01). Logistic regression models identified WD as a predictor of miscarriage and low birth weight (OR: 6.0; CI: 1.1-33.3; p < 0.05) but not of birth defects. Neither therapies (D-penicillamine 300 mg or zinc acetate 150 mg) nor disease presentation (hepatic and/or neurological) were associated with obstetric complications in WD subjects. Conclusion: there was a higher incidence of menses irregularities in untreated females with WD. In addition, our data suggest that treated WD still carries a higher risk of spontaneous abortion and low birth weight when compared to matched control groups with and without liver disease.
- N170 Asymmetry as an Index of Inferior Occipital Dysfunction in Patients With Symptomatic Occipital Lobe EpilepsyPublication . Lopes, R; Cabral, P; Canas, N; Breia, P; Foreid, JP; Calado, E; Silva, R; Leal, AObjective: Localizing epileptic foci in posterior brain epilepsy remains a difficult exercise in surgery for epilepsy evaluation. Neither clinical manifestations, neurological, EEG nor neuropsychological evaluations provide strong information about the area of onset, and fast spread of paroxysms often produces mixed features of occipital, temporal and parietal symptoms. We investigated the usefulness of the N170 event-related potential to map epileptic activity in these patients. Methods: A group of seven patients with symptomatic posterior cortex epilepsy were submitted to a high-resolution EEG (78 electrodes), with recordings of interictal spikes and face-evoked N170. Generators of spikes and N170 were localized by source analysis. Range of normal N170 asymmetry was determined in 30 healthy volunteers. Results: In 3 out of 7 patients the N170 inter-hemispheric asymmetry was outside control values. Those were the patients whose spike sources were nearest (within 3 cm) to the fusiform gyrus, while foci further away did not affect the N170 ratio. Conclusions: N170 event-related potential provides useful information about focal cortical dysfunction produced by epileptic foci located in the close neighborhood of the fusiform gyrus, but are unaffected by foci further away. Significance: The N170 evoked by faces can improve the epileptic foci localization in posterior brain epilepsy.
- Neuropsychological Abnormalities in Children with the Panayiotopoulos Syndrome Point to Parietal Lobe DysfunctionPublication . Lopes, R; Simões, M; Leal, APanayiotopoulos syndrome (PS) is a common epilepsy syndrome associated with rare clinical seizures and unknown localization of the epileptogenic area. Despite findings of normal development in patientswith PS, recent neuropsychological studies point to subtle and diverse cognitive impairments. No well-outlined hypothesis about the localization of the brain dysfunction responsible for these impairments has been proposed.We further explored the cognitive dysfunctions in PS andmade inferences on the most likely anatomical localization of brain impairment. A group of 19 patients (aged 6–12) with PS was rated according to spike activity and lateralization. The patients were submitted to a neuropsychological evaluation to assess general intelligence, memory, language, visual–perceptual abilities, attention, and executive functions. Using 35-channel scalp EEG recordings, the N170 face-evoked event-related potential (ERP)was obtained to assess the functional integrity of the ventral pathway. All patientswith PS showed normal IQ but subtle and consistent neurocognitive impairments. Namely, we found abnormalities in the copy task of the Rey–Osterrieth Complex Figure and in theNarrative Memory Test. There was no correlation between neuropsychological impairments with spike activity and hemispheric spike lateralization. The N170 ERP was normal in all patients except for one. Our neuropsychological findings demonstrate impairments in visual–perceptual abilities and in semantic processing. These findings, paired with the absence of occipital lobe dysfunction in all neuropsychological studies of PS performed to this date, support the existence of parietal lobe dysfunction.
- Review of Piezoelectrical Materials Potentially Useful for Peripheral Nerve RepairPublication . Casal, D; Casimiro, MH; Ferreira, L; Leal, JP; Rodrigues, G; Lopes, R; Lino Moura, D; Gonçalves, L; Lago, J; Pais, D; Santos, PIt has increasingly been recognized that electrical currents play a pivotal role in cell migration and tissue repair, in a process named "galvanotaxis". In this review, we summarize the current evidence supporting the potential benefits of electric stimulation (ES) in the physiology of peripheral nerve repair (PNR). Moreover, we discuss the potential of piezoelectric materials in this context. The use of these materials has deserved great attention, as the movement of the body or of the external environment can be used to power internally the electrical properties of devices used for providing ES or acting as sensory receptors in artificial skin (e-skin). The fact that organic materials sustain spontaneous degradation inside the body means their piezoelectric effect is limited in duration. In the case of PNR, this is not necessarily problematic, as ES is only required during the regeneration period. Arguably, piezoelectric materials have the potential to revolutionize PNR with new biomedical devices that range from scaffolds and nerve-guiding conduits to sensory or efferent components of e-skin. However, much remains to be learned regarding piezoelectric materials, their use in manufacturing of biomedical devices, and their sterilization process, to fine-tune their safe, effective, and predictable in vivo application.