Browsing by Author "Ferreira, Aníbal"
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- Biochemical Clusters as Substitutes of Bone Biopsies in Kidney Transplant Patients.Publication . Ferreira, Ana Carina; Mendes, Marco; Silva, Cecília; Cotovio, Patrícia; Aires, Inês; Navarro, David; Caeiro, Fernando; Salvador, Rute; Correia, Bruna; Cabral, Guadalupe; Nolasco, Fernando; Ferreira, AníbalBone and mineral metabolism abnormalities are frequent in kidney transplant recipients and have been associated with cardiovascular morbidity. The primary aim of this study was to analyse the association between routine clinically available biochemical evaluation, non-routine histomorphometric bone evaluation, and vascular disease in kidney transplanted patients. A cross-sectional analysis was performed on 69 patients, 1-year after kidney transplantation. Laboratory analysis, radiography of hands and pelvis, bone biopsy, bone densitometry, and coronary CT were performed. One-year post-transplantation, nearly one-third of the patients presented with hypercalcemia, 16% had hypophosphatemia, 39.3% had iPTH levels > 150 pg/mL, 20.3% had BALP levels > 40 U/L, and 26.1% had hypovitaminosis D. Evaluation of extraosseous calcifications revealed low Adragão and Agatston scores. We divided patients into three clusters, according to laboratory results routinely used in clinical practice: hypercalcemia and hyperparathyroidism (Cluster1); hypercalcemia and high BALP levels (Cluster2); hypophosphatemia and vitamin D deficiency (Cluster 3). Patients in clusters 1 and 2 had higher cortical porosity (p = 0.001) and osteoid measurements, although there was no difference in the presence of abnormal mineralization, or low volume. Patients in cluster 2 had a higher BFR/BS (half of the patients in cluster 2 had high bone turnover), and most patients in cluster 1 had low or normal bone turnover. Cluster 3 has no differences in volume, or turnover, but 60% of the patients presented with pre-osteomalacia. All three clusters were associated with high vascular calcifications scores. Vascular calcifications scores were not related to higher bone mineral density. Instead, an association was found between a higher Adragão score and the presence of osteoporosis at the femoral neck (p = 0.008). In conclusion, inferring bone TMV by daily clinical biochemical analysis can be misleading, and bone biopsy is important for assessing both bone turnover and mineralization after kidney transplantation, although hypophosphatemia combined with vitamin D deficiency is associated with abnormal mineralization. The presence of hypercalcemia with high levels of PTH or high levels of BALP, or hypophosphatemia and vitamin D deficiency should remind us to screen vascular calcification status of patients.Clinical Research: ClinicalTrials.gov ID NCT02751099.
- Calcium Polystyrene Sulfonate-Induced Colitis: Advanced Characterization of Crystal Nature With Infrared Spectroscopy.Publication . Vidal, Helena; Salgado, Vilma; Alves, Patrícia; Fonseca, Nuno Moreira; Frochot, Vincent; Ferreira, Aníbal; OxfordClassical potassium binders are used in the treatment of hyperkalemia and are widely associated with gastrointestinal side effects, with crystal colonic injury being rare but potentially fatal. In this report, we describe the case of an 82-year-old male with hyperkalemia and calcium polystyrene sulfonate crystal-associated colonic necrosis. Traditionally, this diagnosis has relied on the examination of crystal morphology and polarization through microscopy. Our study enhances crystal identification by incorporating an analysis of the physical characteristics of the crystals using infrared spectroscopy. This is the first description, to our knowledge, of the calcium polystyrene sulfonate infrared spectrum.