Paratirotoxicosis y tumor cervical palpable: caso clínico de cáncer de paratiroides

ResumenIntroducciónEl cáncer de paratiroides es poco frecuente. Suele presentarse como hiperparatiroidismo primario, en ocasiones como crisis hipercalcémica, con malestar general, náuseas, vómitos, alteraciones del ánimo y pérdida de peso. En algunos casos se presenta como osteítis fibrosa quística, osteopenia difusa, osteoporosis y fracturas patológicas. El diagnóstico suele estar dado por biopsia quirúrgica que muestra invasión a estructuras adyacentes, o metástasis locales y distantes. El tratamiento es la resección quirúrgica del tumor, sin uso de terapias adyuvantes. Su tasa de recurrencia es alta, de 25 a 100%. Algunos factores de mal pronóstico son metástasis a linfonodos en la presentación inicial, metástasis distantes y carcinomas no funcionantes.Caso clínicoPaciente masculino de 64 años que consultó por compromiso del estado general, bradipsiquia, poliuria, cefalea y masa cervical. Además presentaba hipercalcemia y gran elevación de PTH. Se realizó resección quirúrgica de la masa cervical, con biopsia rápida con atipias y mitosis 1/10, y de un nódulo hiperplásico tiroideo. Tras esto, sus niveles de PTH disminuyeron, así como también descendieron sus niveles de calcio.DiscusiónLos pacientes que presentan cáncer de paratiroides suelen tener valores más elevados de calcemia y PTH. Para su diagnóstico, no se recomienda usar biopsia por punción, por riesgo de diseminación y por el bajo rendimiento de esta técnica.ConclusiónPese a ser poco frecuente, se debe pensar en cáncer de paratiroides en el contexto de un paciente con hipercalcemia, especialmente si presenta PTH muy elevada. La sospecha clínica de este diagnóstico tiene directa relación con la posibilidad de tratamiento y pronóstico de la enfermedad.AbstractIntroductionParathyroid cancer is rare. Usually presented as primary hyperparathyroidism, sometimes as hypercalcemic crisis, with general malaise, nausea, vomiting, mood disturbances and low weight. In some cases it occurs as osteitis fibrosa cystica, diffuse osteopenia, osteoporosis and pathological fractures. The diagnosis is usually made by surgical biopsy shows invasion of adjacent structures, or local and distant metastases. The treatment is surgical resection of the tumor, without the use of adjuvant therapies. Their recurrence rate is high, 25 to 100%. Poor prognostic factors are lymph node metastases at initial presentation, distant metastases and nonfunctional carcinomas.Case reportMale patient consulted for 64 years in general conditions, bradypsychia, polyuria, headache and neck mass. He also had hypercalcemia and high elevation of PTH. Surgical resection of the cervical mass was performed, with rapid biopsy atypia and mitosis 1/10, and hyperplastic thyroid nodule. After this, PTH decreased levels as well as levels of calcium.DiscussionPatients with parathyroid cancer tend to have higher serum calcium and PTH of values. For diagnosis, it is not recommended to use needle biopsy, risk of spread and the poor performance of this technique.ConclusionDespite being rare, you should think parathyroid cancer in the context of a patient with hypercalcemia, especially if you have very high PTH. The clinical suspicion of this diagnosis is directly related to the possibility of treatment and prognosis of the disease

Non-heme iron enzymes: Contrasts to heme catalysis

Non-heme iron enzymes catalyze a wide range of O(2) reactions, paralleling those of heme systems. Non-heme iron active sites are, however, much more difficult to study because they do not exhibit the intense spectral features characteristic of the porphyrin ligand. A spectroscopic methodology was developed that provides significant mechanistic insight into the reactivity of non-heme ferrous active sites. These studies reveal a general mechanistic strategy used by these enzymes and differences in substrate and cofactor interactions dependent on their requirement for activation by iron. Contributions to O(2) activation have been elucidated for non-heme relative to heme ligand sets, and major differences in reactivity are defined with respect to the heterolytic and homolytic cleavage of O—O bonds

Biological and molecular properties of yellow venom of the Amazonian coral snake Micrurus surinamensis

Introduction: The coral snake Micrurus surinamensis, which is widely distributed throughout Amazonia, has a neurotoxic venom. It is important to characterize the biological and molecular properties of this venom in order to develop effective antitoxins. Methods: Toxins from the venom of M. surinamensis were analyzed by two-dimensional polyacrylamide gel electrophoresis and their neurotoxic effects in vivo were evaluated. Results and Conclusions: Most proteins in the venom had masses < 14kDa, low phospholipase A2 activity, and no proteolytic activity. The toxins inhibited the coagulation cascade. The venom had neurotoxic effects in mice, with a median lethal dose upon intravenous administration of 700 µg/kg. Immunogenic studies revealed abundant cross-reactivity of antielapidic serum with 14kDa toxins and limited cross-reactivity with toxins < 10kDa. These results indicate that antielapidic serum against M. surinamensis venom has weak potency (0.35mg/ml) in mice. © 2017, Sociedade Brasileira de Medicina Tropical. All rights reserved