Juan Carlos de Vicente Rodríguez

Interaction of gypsum with As(V)-bearing aqueous solutions: Surface precipitation of guerinite, sainfeldite, and Ca2NaH(AsO4)2·6H2O, a synthetic arsenate

Abstract The interaction of arsenate-bearing aqueous solutions with gypsum at a starting pH of 9 and 25 °C results in surface precipitation of guerinite, Ca5(HAsO4)2(AsO4)2·9H2O, sainfeldite, Ca5(HAsO4)2(AsO4)2·4H2O, and occasionally Ca2Na(HAsO4)(AsO4)·6H2O, a new arsenate. These three solid phases are characterized by the simultaneous presence of HAsO42- and AsO43- groups in their structure, which is explainable since crystallization occurs within a pH range in which both HAsO42- and AsO43- are available in the aqueous solution. The interaction leads to a decrease in the As(V) concentration in the aqueous phase to reach values controlled by the solubility of these solid phases. The study combines several macroscopic experiments, in which changes in the solution chemistry are monitored as a function of time, with the characterization of solid phases by SEM-EDS and XRD. The crystal morphologies of the precipitating phases are interpreted on the basis of their respective structures. The thermodynamic solubility products of both guerinite and the new arsenate have been determined, being 10-31.17±0.05 and 10-13.83±0.03, respectively. The reaction paths followed by the system and the equilibrium endpoints have been modeled using the geochemical code PHREEQC.

Spontaneous fracture of hypertrophied genial tubercles

A case of spontaneous fracture of hypertrophied genial tubercles is reported. This is an uncommon event with only six previously reported cases. This entity is usually associated with severe edentulous bone resorption, a condition related to the pathogenesis of this fracture. Clinical complaints include painful swelling of the floor of the mouth and impaired tongue function. If left untreated, mucosal inflammatory changes may appear and a biopsy should be performed. Total recovery is obtained after removal of the fractured fragments.

Small Cell Undifferentiated Carcinoma of the Submandibular Gland with Neuroendocrine Features

This article reports the clinical, histopathologic, and immunohistochemical findings in a case of small cell undifferentiated carcinoma of the submandibular gland. The tumor was composed of anaplastic cells slightly larger than lymphocytes without ductal differentiation. On immunohistochemical analysis, the tumor contained cells that reacted positively with antibodies to cytokeratin, neuron-specific enolase, synaptophysin, and chromogranin. The present case supports the hypothesis that small cell undifferentiated carcinomas of the salivary glands arise from presumed multipotential ductal stem cells. When this tumor entity is located on the salivary glands, it appears to behave less aggressively than when it is a primary tumor of the bronchial tree.

Diagnóstico y plan de tratamiento en cirugía ortognática

La cirugia ortognatica es una practica cada vez mas extendida y que, en el momento actual, no se aplica exclusivamente en deformidades dentofaciales extremadamente severas. Debido a sus implicaciones tanto esteticas como funcionales, los pacientes aceptan cada vez con mas frecuencia someterse a este tipo de tratamientos. El objetivo de este trabajo consiste en mostrar al odontologo general algunos de los aspectos concernientes al manejo que realiza el cirujano con respecto al diagnostico y plan de tratamiento de este tipo de deformidades. Palabras clave: Cirugia ortognatica. Deformidades dentofaciales.

Keratocyst Capnocytophaga superinfection

INTRODUCTION Capnocytophaga spp are Gram-negative bacteria that cause severe infections in immunosuppressed patients. This situation is extremely rare in immunocompetent patients. CASE REPORT This clinical report describes the unusual infection of an immunocompetent patient with Capnocytophaga spp. The imaging studies showed the existence of a cyst in the left jawbone. After treatment and a microbiological study of the content, it was found to be an outbreak of septicaemia. DISCUSSION Capnocytophaga spp, commensal bacteria of the oral cavity, can lead to serious illness and that is why an empirical treatment is needed until a diagnostic confirmation can be obtained.

Carcinoma escamoso oral en pacientes trasplantados: Estado actual de la cuestión

Los canceres de cabeza y cuello representan el 15% de todos los tumores malignos en los pacientes trasplantados. La principal causa que justifica este incremento de incidencia con relacion a la poblacion general, es el significativo aumento de los canceres de labio. En el presente trabajo se documentan dos casos de carcinoma apidermoide oral desarrollados en pacientes sometidos a un trasplante renal. Se realiza una revision sobre la cuestion, definiendo aquellos aspectos de mayor trascendencia clinica para el odonto-estomatologo. Palabras clave: Carcinoma escamoso oral. Neoplasias en trasplantados. Inmunosupresion.