Timectomía toracoscópica en pacientes con Miastenia Gravis juvenil

Objetivo: Describir la evolución clínica postquirúrgica de una serie de casos de pacientes con Miastenia Gravis juvenil (MGJ) tratados con timectomía por toraoscópica videoasistida (TVA) derecha. Materiales y Métodos: Estudio retrospectivo que incluyó 13 pacientes pediátricos con diagnóstico de MGJ sometidos a timectomía toracoscópica derecha en la Unidad Médica de Alta Especialidad Hospital de Pediatría, Centro Médico Nacional Siglo XXI de México, entre marzo de 2016 y abril de 2022. Los pacientes fueron caracterizados clínicamente y la enfermedad fue clasificada de acuerdo a los criterios de Osserman. La evolución postquirúrgica se evaluó con la clasificación de DeFilippi para determinar la proporción de pacientes con mejoría y la remisión completa. Resultados: Los pacientes incluidos fueron, en su mayoría, mujeres (84,6%) con edad promedio al diagnóstico fue de 11,1 ± 3,1 años. Las cuatro clasificaciones de MG fueron incluidas, con mayor proporción de MG generalizada leve (38,5%), seguida de ocular (23,1%) y generalizada moderada grave (23,1%). La evaluación de la progresión postquirúrgica demostró que a los tres meses de seguimiento 92,3% presentó mejorías, incluyendo la disminución del uso de medicamentos. La remisión total solo se registró en uno de los pacientes. Los pacientes que tuvieron cirugía antes de los 12 meses de evolución de la MGJ presentaron mejores resultados post timectomía por TVA. Conclusión: Se demostró la utilidad de timectomía por TVA en pacientes pediátricos mexicanos con MGJ. Nuestra experiencia agrega evidencia de que los pacientes pediátricos se benefician de la timectomía, mejorando su estado clínico y disminuyendo el uso de medicamentos y complicaciones e la enfermedad.

Objective: To describe the post-surgical clinical evolution of a case series of patients with juvenile myasthenia gravis (JMG) treated with right video-assisted thoracoscopic (TVA) thymectomy. Materials and Methods: Retrospective study that included 13 pediatric patients with JMG who underwent right TVA thymectomy at the Siglo XXI National Medical Center of Mexico between March 2016 and April 2022. Patients were clinically characterized, and the disease was classified according to Osserman's criteria. Post-surgical evolution was evaluated using the DeFilippi classification to determine the proportion of patients with improvement and complete remission. Results: The included patients were mostly women (84.6%) with a mean age at diagnosis of 11.1 ± 3.1 years. The four MG classifications were included, with the highest proportion of mild generalized MG (38.5%), followed by ocular (23.1%) and moderate-severe generalized (23.1%). The evaluation of post-surgical progression showed that after three months of follow-up, 92.3% presented improvements, including a decrease in the use of medications. Complete remission was only recorded in one of the patients. Patients who underwent surgery before 12 months of evolution of JMG had better results after TVA thymectomy. Conclusion: The usefulness of TVA thymectomy in Mexican pediatric patients with JMG was demonstrated. Our experience adds evidence that pediatric patients benefit from thymectomy by improving their clinical status and decreasing the use of medications and complications of the disease.

Melatonin decreases in vitro viability and migration of spheres derived from CF41.Mg canine mammary carcinoma cells.

BACKGROUND: Mammary cancer is a common disease affecting female dogs, where approximately 50% of the cases are malignant. There is a subpopulation of cancer cells with stem cell-like features within the tumour microenvironment, which can form in vitro spheres, cell structures that grow in anchor-free conditions. This cell population shows resistance to conventional antitumor treatments explaining in part the recurrence of some type of cancers. It has been previously reported that spheres derived from CF41.Mg canine mammary carcinoma cells exhibit several stemness features. Melatonin has shown antitumor effects on cancer mammary cells; nevertheless, its effects have been poorly evaluated on canine mammary cancer stem-like cells. In this regard, it has described that melatonin decreases the expression of OCT-4 in CMT-U2229 mammary cancer cells, a transcription factor that participates in the modulation of self-renewal and drug resistance in cancer stem-like cells. The aim of this study was to compare the effects of melatonin on viability and migration of canine mammary carcinoma CF41.Mg-spheres, and CF41.Mg-parental cells. CF41.Mg cells were grown in DMEM high-glucose medium containing 10% bovine foetal serum. CF41.Mg-spheres were cultured in ultra-low attachment plates with serum-free DMEM/F12 containing several growth factors. Cell viability (MTS reduction) and migration (transwell) assays were conducted in presence of melatonin (0.01, 0.1 or 1 mM). RESULTS: Melatonin decreased cell viability at 1 mM (P < 0.05), with a significant reduction in spheres compared to parental cells at 24 and 48 h (P < 0.05). Cell migration was inhibited in response to non-cytotoxic concentration of melatonin (0.1 mM) (P < 0.05) in spheres and monolayer of cells, no significant differences were detected between both cell subtypes. CONCLUSIONS: These results indicate that melatonin reduces viability and migration of CF41.Mg cells, where spheres exhibit greater sensitivity to the hormone. Thus, melatonin represents a valuable potential agent against mammary cancer cells, especially cancer stem-like cells.

Characterization of the 2012 highly pathogenic avian influenza H7N3 virus isolated from poultry in an outbreak in Mexico: pathobiology and vaccine protection.

In June of 2012, an H7N3 highly pathogenic avian influenza (HPAI) virus was identified as the cause of a severe disease outbreak in commercial laying chicken farms in Mexico. The purpose of this study was to characterize the Mexican 2012 H7N3 HPAI virus (A/chicken/Jalisco/CPA1/2012) and determine the protection against the virus conferred by different H7 inactivated vaccines in chickens. Both adult and young chickens intranasally inoculated with the virus became infected and died at between 2 and 4 days postinoculation (p.i.). High virus titers and viral replication in many tissues were demonstrated at 2 days p.i. in infected birds. The virus from Jalisco, Mexico, had high sequence similarity of greater than 97% to the sequences of wild bird viruses from North America in all eight gene segments. The hemagglutinin gene of the virus contained a 24-nucleotide insert at the hemagglutinin cleavage site which had 100% sequence identity to chicken 28S rRNA, suggesting that the insert was the result of nonhomologous recombination with the host genome. For vaccine protection studies, both U.S. H7 low-pathogenic avian influenza (LPAI) viruses and a 2006 Mexican H7 LPAI virus were tested as antigens in experimental oil emulsion vaccines and injected into chickens 3 weeks prior to challenge. All H7 vaccines tested provided ≥90% protection against clinical disease after challenge and decreased the number of birds shedding virus and the titers of virus shed. This study demonstrates the pathological consequences of the infection of chickens with the 2012 Mexican lineage H7N3 HPAI virus and provides support for effective programs of vaccination against this virus in poultry.