Comparative dissolution profiles of two anti-emetic delayed release dosage forms of doxylamine and pyridoxine: Xonvea® tablets vs. Cariban® capsules.

OBJECTIVE: Nausea and vomiting of pregnancy is a common disease that affects many women suffering from mild to severe symptoms. Amongst the different treatments, a fixed dose combination of doxylamine and pyridoxine has been proven safe and effective although the mechanism of action is not well established. There are different pharmaceutical dosage forms in the European market. The objective of this study was to compare the characteristics of a capsule formulation, Cariban® and a tablet formulation, Xonvea® to evaluate the potential impact of their release profiles on their onset of action. MATERIALS AND METHODS: 10 mg/10 mg of doxylamine succinate/pyridoxine hydrochloride capsules (Cariban®) and tablets (Xonvea®) were used as reference materials. Appearance, mass, composition, and in vitro dissolution profiles were compared. Bibliographic data from 4 pharmacokinetic studies of Xonvea® and 1 pharmacokinetic study of Cariban® was reviewed. RESULTS: In vitro dissolution studies showed significant differences in dissolution profiles of tablets and capsules. The later exhibiting some release of both drug substances in acid conditions followed by a non-complete release after a total of 3 hours while the tablets demonstrated gastro-resistant properties and rapid API release in about 20-30 minutes after the acid stage. Comparison of PK data showed greater Cmax for pyridoxine. CONCLUSIONS: At pH 6.8, complete and faster release of the fixed dose combination for Xonvea® gastro-resistant tablets compared to Cariban® capsules could possibly explain the greater Cmax observed in vivo for the tablet's formulation. This could translate into faster onset of action and relief of nausea for pregnant women taking the tablets vs. the capsules.

Alternativas reconstructivas post maxilectomía por enfermedad neoplásica / Reconstructive alternatives post maxillectomy for oncologic disease

Introducción: La reconstrucción de defectos mediofaciales representa un gran desafío. Los maxilares son los huesos más importantes del esqueleto facial, proveen soporte entre base del cráneo y arcos maxilares, separan cavidades, participan en la deglución, fonación, masticación, visión y apariencia. La maxilectomía conlleva diferentes grados de alteración funcional. La reconstrucción maxilar va desde el uso de prótesis obturadoras, colgajos locales hasta colgajos libres. Objetivo: Presentar las alternativas reconstructivas post maxilectomía por enfermedad neoplásica utilizadas en nuestro centro. Pacientes y Métodos: Análisis retrospectivo de todos los pacientes sometidos a maxilectomía por causa oncológica entre los años 2008 y 2011. Resultados: La serie estuvo compuesta por 12 pacientes, 8 mujeres, mediana de edad 57 años (rango 25-84). Se realizó maxilectomía Tipo IIA a cinco pacientes, Tipo IIB a dos pacientes, Tipo IIIA a cuatro pacientes y IIIB a un paciente. Se logró R0 en todos los casos. La reconstrucción se realizó con prótesis obturadora en cuatro pacientes, tres pacientes con colgajos pediculados y cinco pacientes con colgajos microquirúrgicos. En todos los pacientes se logró un resultado funcional adecuado. En un paciente hubo pérdida parcial del colgajo. Discusión: Es recomendable ajustar la alternativa reconstructiva según el pronóstico del paciente. Prótesis obturadoras son una opción para pacientes seleccionados. El colgajo de músculo temporal presenta un buen resultado funcional, recomendado en pacientes con enfermedad avanzada y mal pronóstico. La reconstrucción microquirúrgica es la alternativa de elección con los mejores resultados funcionales y estéticos en pacientes con maxilectomías Tipo II, III y IV.

The reconstruction of midfacial defects is a major challenge. The maxillary bones are the more important of the facial skeleton, provide support between skull base and maxillary arches, separate cavities and are involved in swallowing, phonation, mastication, vision and appearance. The maxillectomy involves varying degrees of functional impairment. The maxillary reconstruction ranges from the use of obturator prosthesis, local flaps to free flaps. Aim: To present the different reconstructive alternatives used after a maxillectomy for oncologic disease in our hospital. Patients and Methods: Retrospective analysis of all patients that was submitted to a maxillectomy for oncologic disease between 2008 and 2011 in our center. Results: The series consisted of 12 patients, 8 women and median age 57 years (range, 25-84). We realized Type IIA maxillectomy in five patients, IIB to two patients, IIIA to four patients and IIIB to one patient. We achieved R0 in all cases. The reconstruction was realized with obturator prosthesis in four patients, three patients with pedicled flaps and five patients were reconstructed with free flaps. All patients obtain an adequate functional status. One patient has partial flap loss. Discussion: Is recommended adjust the surgical choice to the patient prognosis. The obturator prosthesis is a good choice for selected group. The temporal muscle flap presents adequate functional results and is recommended in advanced disease and poor prognosis. The microsurgical reconstruction is the best choice with better functional and aesthetics outcomes in type II, III and IV maxillectomy.

Navigation system for computer assisted tumor ablation using radio frequency.

Currently, physicians are using a new technique based on radiofrequency (RF) induced hyperthermia, to treat tumors in the musculoskeletal system. This method uses a RF probe, which is placed inside the tumor, which in turn is heated within the active volume of the probe, eliminating in this way the tumor cells without affecting healthy cells. For this treatment, the surgeon must know the exact shape and location of the tumor. Usually a nuclear magnetic resonance imaging (NMRI) study is performed before surgery. Ultrasound imaging is used to locate the tumor intraoperatively. In this work is presented a computer system to build a 3D model of the tumor and adjacent bones based on segmented images from the preoperative NMRI study. Then, during surgery, the model will be registered with the anatomy of the patient, using intraoperative ultrasound images segmented by the surgeon. This work is part of a larger project, which will be a complete computer aided surgery (CAS) system to help train physicians in radiofrequency treatment and to make the procedure more reliable and efficient.

Aumento del antígeno prostático específico en hipertiroidismo / Increase of the specific prostatic antigen in a pa tient with hyperthyroidism

Comentamos el caso clínico de un paciente con antecedentes de hiperplasia prostática intervenida quirúrgicamente que presenta, años después, un marcado aumento del antígeno prostático específico (PSA). Este incremento se produce en el contexto de un episodio de hipertiroidismo. Discutimos la posible asociación entre el aumento del PSA y enfermedad tiroidea (AU)

Immunohistochemical expression of S-100 beta in choroidal melanomas.

OBJECTIVE: To investigate the expressivity of S-100 beta antibodies in choroidal melanomas and to compare it with that of S-100 protein and HMB-45. DESIGN: Twenty-seven choroidal melanoma specimens obtained from the McGill University Ophthalmic Pathology Registry were classified as spindle cell, epithelioid cell or mixed-cell type. Immunohistochemistry was performed using the standard peroxidase-antiperoxidase technique with monoclonal HMB-45, polyclonal S-100, polyclonal S-100 beta and monoclonal S-100 alpha beta antibodies in formalin-fixed, paraffin-embedded sections. OUTCOME MEASURE: Intensity of immunoreaction. The result was considered positive when at least five focal areas of stained cells were observed within the tumour. RESULTS: All 27 tumours were positive for HMB-45, 19 (70%) for S-100, 23 (85%) for S-100 beta, and 21 (78%) for S-100 alpha beta. No correlation was found between the intensity of the immunoreaction and cell classification. CONCLUSIONS: HMB-45 is the most reliable marker for choroidal melanomas. S-100 beta is a more sensitive marker than S-100 for choroidal melanomas regardless of cell type. Contrary to previous reports, S-100 beta should not be considered a useful immunomarker to differentiate between primary choroidal melanoma and cutaneous melanoma metastatic to the choroid.

Primary choroidal melanoma in a patient with previous cutaneous melanoma.

A 67-year-old woman with a history of a skin melanoma that was excised 7 years previously had a 6-month history of decreased vision in her right eye. A choroidal melanoma was diagnosed clinically, and the eye was enucleated. The results of a histopathological examination revealed a primary uveal melanoma. Slides of the skin melanoma were obtained, and the initial diagnosis was confirmed. In an attempt to illustrate a biological difference between the 2 melanomas, immunohistochemical studies were performed on sections of the 2 specimens using S-100 protein, HMB-45, and S-100-beta. Primary cutaneous and choroidal melanomas appearing in a patient with no predisposition are rare; this is believed to be only the fifth such case reported in the literature.