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- Early disrupted neurovascular coupling and changed event level hemodynamic response function in type 2 diabetes: an fMRI studyPublication . Duarte, JV; Pereira, JM; Quendera, B; Raimundo, M; Moreno, C; Gomes, L; Carrilho, F; Castelo-Branco, MType 2 diabetes (T2DM) patients develop vascular complications and have increased risk for neurophysiological impairment. Vascular pathophysiology may alter the blood flow regulation in cerebral microvasculature, affecting neurovascular coupling. Reduced fMRI signal can result from decreased neuronal activation or disrupted neurovascular coupling. The uncertainty about pathophysiological mechanisms (neurodegenerative, vascular, or both) underlying brain function impairments remains. In this cross-sectional study, we investigated if the hemodynamic response function (HRF) in lesion-free brains of patients is altered by measuring BOLD (Blood Oxygenation Level-Dependent) response to visual motion stimuli. We used a standard block design to examine the BOLD response and an event-related deconvolution approach. Importantly, the latter allowed for the first time to directly extract the true shape of HRF without any assumption and probe neurovascular coupling, using performance-matched stimuli. We discovered a change in HRF in early stages of diabetes. T2DM patients show significantly different fMRI response profiles. Our visual paradigm therefore demonstrated impaired neurovascular coupling in intact brain tissue. This implies that functional studies in T2DM require the definition of HRF, only achievable with deconvolution in event-related experiments. Further investigation of the mechanisms underlying impaired neurovascular coupling is needed to understand and potentially prevent the progression of brain function decrements in diabetes.
- Relations between Cardiac and Visual Phenotypes in Diabetes: A Multivariate ApproachPublication . Oliveiros, B; Sanches, M; Quendera, B; Graça, B; Guelho, D; Gomes, L; Carrilho, F; Caseiro-Alves, F; Castelo-Branco, MCardiovascular disease and diabetes represent a major public health concern. The former is the most frequent cause of death and disability in patients with type 2 diabetes, where left ventricular dysfunction is highly prevalent. Moreover, diabetic retinopathy is becoming a dominant cause of visual impairment and blindness. The complex relation between cardiovascular disease and diabetic retinopathy as a function of ageing, obesity and hypertension remains to be clarified. Here, we investigated such relations in patients with diabetes type 2, in subjects with neither overt heart disease nor advanced proliferative diabetic retinopathy. We studied 47 patients and 50 controls, aged between 45 and 65 years, equally distributed according to gender. From the 36 measures regarding visual structure and function, and the 11 measures concerning left ventricle function, we performed data reduction to obtain eight new derived variables, seven of which related to the eye, adjusted for age, gender, body mass index and high blood pressure using both discriminant analysis (DA) and logistic regression (LR). We found moderate to strong correlation between left ventricle function and the eye constructs: minimum correlation was found for psychophysical motion thresholds (DA: 0.734; LR: 0.666), while the maximum correlation was achieved with structural volume density in the neural retina (DA: 0.786; LR: 0.788). Controlling the effect of pairwise correlated visual constructs, the parameters that were most correlated to left ventricle function were volume density in retina and thickness of the retinal nerve fiber layers (adjusted multiple R2 is 0.819 and 0.730 for DA and LR), with additional contribution of psychophysical loss in achromatic contrast discrimination. We conclude that visual structural and functional changes in type 2 diabetes are related to heart dysfunction, when the effects of clinical, demographic and associated risk factors are taken into account, revealing a genuine relation between cardiac and retinal diabetic phenotypes.
- Controversies in the management of hyperglycaemic emergencies in adults with diabetesPublication . Cardoso, L; Vicente, N; Rodrigues, D; Gomes, L; Carrilho, FHyperglycaemic emergencies are associated with significant morbi-mortality and healthcare costs. Management consists on fluid replacement, insulin therapy, and electrolyte correction. However, some areas of patient management remain debatable. In patients without respiratory failure or haemodynamic instability, arterial and venous pH and bicarbonate measurements are comparable. Fluid choice varies upon replenishment phase and patient's condition. If patient is severely hypovolaemic, normal saline solution should be the first option. However, if patient has mild/moderate dehydration, fluid choice must take in consideration sodium concentration. Insulin therapy should be guided by β-hydroxybutyrate normalization and not by blood glucose. Variations of conventional insulin infusion protocols emerged recently. Priming dose of insulin may not be required, and fixed rate insulin infusion represents the best option to suppress hepatic glucose production, ketogenesis, and lipolysis. Concomitant administration of basal insulin analogues with regular insulin infusion accelerates ketoacidosis resolution and prevents rebound hyperglycaemia. Simpler protocols using subcutaneous rapid-acting insulin analogues for mild/moderate diabetic ketoacidosis treatment have proven to be safe and effective, but further studies are required to confirm these results. Treatment with bicarbonate, phosphate, and low-molecular-weight heparin is still disputable, and randomized controlled trials are urgently needed to optimize patient management and decrease the morbi-mortality of hyperglycaemic emergencies.
- Emerging drugs for Cushing's diseasePublication . Guelho, DL; Grossman, ABINTRODUCTION: Considering the effects of uncontrolled hypercortisolism on morbidity and mortality, there is a clear need for effective medical therapy for patients with Cushing's disease (CD). Therefore, the search for new medical effective tools remains active, and already promising results have been obtained. AREAS COVERED: The importance of the design and conduct of trials to validate old drugs or to test new compounds is discussed. The results of the ongoing clinical trials, targeting the specific properties of drugs, such as ketoconazole, LCI699, mifepristone, etomidate and pasireotide, are also reported. The authors also emphasise the advantages and drawbacks of each particular drug, and the potential combined use of agents with complementary mechanisms of action. EXPERT OPINION: CD is an excellent example of a situation where effective therapy is essential, but where the balance of risk and benefit must be carefully judged. Metyrapone is the drug of choice when rapid control of the hypercortisolaemia is required, ketoconazole represents a good second-line drug, although in the future LCI699 may be a better alternative. Mifepristone can also be used in the rare situation when previous drugs are inappropriate. Etomidate is useful where immediate parenteral action is required. For drugs working directly on the pituitary, cabergoline is occasionally effective and pasireotide can be attempted in patients with mild CD.
- Long-term survival in a patient with brain metastases of papillary thyroid carcinomaPublication . Guelho, D; Ribeiro, C; Melo, M; Carrilho, FWe present the case of a 43-year-old woman who underwent total thyroidectomy with bilateral lymphadenectomy for a papillary thyroid carcinoma (PTC), solid variant (T4bN1bMx), with V600E BRAF mutation. After ablative therapy, she presented undetectable thyroglobulin (Tg) but progressively increasing anti-Tg antibodies (TgAbs). During follow-up, nodal, lung and brain metastases were identified. She was submitted to surgical excision of lung lesions, radiosurgery of brain metastases and five radioiodine treatments. The latest brain MRI showed no lesions, pulmonary CT showed stable micronodules and there was progressive reduction in TgAbs. This is a peculiar case of a PTC with lung and brain metastatic lesions detected through TgAbs. Initial histological and molecular study suggested a more aggressive clinical behaviour, which was eventually confirmed. Although PTC brain metastases are extremely rare and present poor prognosis, our patient presented a good response to treatment and longer survival than usually reported for similar cases.
- Novel FGFR1 mutations in Kallmann syndrome and normosmic idiopathic hypogonadotropic hypogonadism: evidence for the involvement of an alternatively spliced isoformPublication . Gonçalves, C; Bastos, M; Pignatelli, D; Borges, T; Aragüés, JM; Fonseca, F; Pereira, BD; Socorro, S; Lemos, MCOBJECTIVE: To determine the prevalence of fibroblast growth factor receptor 1 (FGFR1) mutations and their predicted functional consequences in patients with idiopathic hypogonadotropic hypogonadism (IHH). DESIGN: Cross-sectional study. SETTING: Multicentric. PATIENT(S): Fifty unrelated patients with IHH (21 with Kallmann syndrome and 29 with normosmic IHH). INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Patients were screened for mutations in FGFR1. The functional consequences of mutations were predicted by in silico structural and conservation analysis. RESULT(S): Heterozygous FGFR1 mutations were identified in six (12%) kindreds. These consisted of frameshift mutations (p.Pro33-Alafs*17 and p.Tyr654*) and missense mutations in the signal peptide (p.Trp4Cys), in the D1 extracellular domain (p.Ser96Cys) and in the cytoplasmic tyrosine kinase domain (p.Met719Val). A missense mutation was identified in the alternatively spliced exon 8A (p.Ala353Thr) that exclusively affects the D3 extracellular domain of FGFR1 isoform IIIb. Structure-based and sequence-based prediction methods and the absence of these variants in 200 normal controls were all consistent with a critical role for the mutations in the activity of the receptor. Oligogenic inheritance (FGFR1/CHD7/PROKR2) was found in one patient. CONCLUSION(S): Two FGFR1 isoforms, IIIb and IIIc, result from alternative splicing of exons 8A and 8B, respectively. Loss-of-function of isoform IIIc is a cause of IHH, whereas isoform IIIb is thought to be redundant. Ours is the first report of normosmic IHH associated with a mutation in the alternatively spliced exon 8A and suggests that this disorder can be caused by defects in either of the two alternatively spliced FGFR1 isoforms
- Resistência à hormonas tiroideiasPublication . Santos, J; Paiva, I; Carvalheiro, M
- Persistent primary hyperparathyroidism: an uncommon location for an ectopic gland: Case report and reviewPublication . Gouveia, S; Rodrigues, D; Barros, L; Ribeiro, C; Albuquerque, A; Carvalheiro, MPrimary hyperparathyroidism (PHPT) is a common endocrine disorder that mainly affects middle-aged women. Patients are usually asymptomatic. The disease might be ascribable to hyperplasia, carcinoma, and single or multiple adenomas. PHPT may be sporadic or familial, the latter comprising multiple endocrine neoplasia type 1 or 2A, familial benign hypocalciuria hypercalcemia, and hyperparathyroidism-jaw tumor syndrome. The most common causes for persistent PHPT are multiglandular disease, and missed abnormal ectopic or orthotopic parathyroid glands. Imaging localization studies should precede a new surgical intervention. Ectopic parathyroid glands are rarely located at the aortopulmonary window. For diagnosis confirmation, 99mTc-sestamibi SPECT/CT seems to be an advantageous test. Another possibility is to perform 99mTc-sestamibi followed by thoracic CT or MRI. Parathyroidectomy may be performed by means of median sternotomy, thoracotomy, or video-assisted thoracoscopy. We describe a case of persistent primary hyperparathyroidism due to the presence of an ectopic parathyroid gland found at the aortopulmonary window. As the investigation necessary to clarify the etiology of recurrent nephrolithiasis proceeded, the diagnosis of PHPT was determined. The patient underwent subtotal parathyroidectomy; nevertheless, PHPT persisted. Genetic syndromes that could account for this condition were excluded. Imaging studies available at that time were not able to locate abnormal glands; moreover, the patient refused to undergo surgical exploration. Later, the patient underwent 99mTc-sestamibi SPECT/CT, which revealed a parathyroid gland at the aortopulmonary window.
- Ácido acetilsalicílico e diabetes mellitusPublication . Paiva, SThe physiopathologic mechanisms underlying cardiovascular disease in diabetic patients are briefly reviewed. The use of inhibitors of platelet aggregation is discussed as being potentially valuable in the pharmacological prevention of this condition. Acetylsalisylic acid turns out to be the reference within the repertoire of currently available drugs since it has been extensively tested in clinical trials. We conclude by discussing the recommendations of the American Diabetes Association (ADA) concerning the primary and secondary prevention of cardiovascular disease in diabetes mellitus.
- Tiroidites agudasPublication . Paiva, S; Bastos, M; Gomes, L; Durão, A; Moreira, A; Barros, L; Rodrigues, D; Ruas, L; Ribeiro, C; Rodrigues, F; Paiva, I; Fagulha, A; Carrilho, F; Geraldes, E; Carvalheiro, M; Ruas, AWe review the pathophysiology, clinical features and therapy of acute thyroiditis. Four cases are reported stressing the role of fine needle aspiration for the diagnosis of this clinical entity.