RESUMO
The goal of the study reported here was to develop a continuous cell line from the squirrel monkey that expresses the species-specific phenotype of impaired sensitivity to glucocorticoids. Thirty milliliters of blood from a male Bolivian squirrel monkey (Saimiri boliviensis boliviensis) was fractionated, and the buffy coat was obtained and incubated in the presence of B95-8 cell-conditioned medium, an abundant source of Epstein-Barr virus (EBV), and 2 micrograms of cyclosporin A/ml. Cell growth was detected within 8 weeks, after which the cells were cloned by use of the limiting dilution method. One clone (4D8) was characterized in detail. The chromosomal count and G-banding pattern confirmed that the cells were of Bolivian squirrel monkey origin. The B-cell origin of these cells was indicated by electron microscopic analysis and was confirmed by expression of CD20. The cells stained strongly for LMP1, a marker of latent EBV infection, and occasionally for the lytic infection marker ZEBRA (BZLF1). The responsiveness of clone 4D8 cells to glucocorticoids was determined by comparing the effects of dexamethasone on cell growth and the induction of a glucocorticoid-inducible mRNA in 4D8 cells with the effects on a human EBV-transformed B-lymphoblast cell line (HL). Dexamethasone inhibited the growth of HL cells, with IC50 of approximately 9 nM, but had no effect on the growth of 4D8 cells. The induction of FK506-binding protein FKBP51 mRNA by dexamethasone was also significantly blunted in 4D8 cells. Thus, we have developed and characterized a squirrel monkey lymphoblastic cell line derived by transformation of B-lymphocytes with EBV; the cell line has diminished growth and transcriptional responses to glucocorticoids.
Assuntos
Linfócitos B/efeitos dos fármacos , Resistência a Medicamentos , Glucocorticoides/farmacologia , Saimiri , Animais , Antígenos CD20/análise , Divisão Celular/efeitos dos fármacos , Linhagem Celular Transformada , Dexametasona/farmacologia , Herpesvirus Humano 4 , Humanos , Imunofenotipagem , Imunofilinas/genética , Masculino , Microscopia Eletrônica , RNA Mensageiro/biossíntese , Especificidade da Espécie , Proteínas de Ligação a TacrolimoRESUMO
Infant botulism is a national problem with over 1000 confirmed cases in the United States since it was first recognized as a distinct clinical entity in 1976. The disease is characterized by a progressive, symmetrical descending paralysis of cranial nerves with eventual involvement of axial and trunk muscle innervation. Most infants progress to complete respiratory failure. An initial report in 1979 recommended early tracheotomy for avoidance of long-term intubation complications. However, over the past 10 years at St. Christopher's Hospital for Children, analysis of airway management in 11 patients with infant botulism revealed a median intubation time of 16 days. Following extubation, all patients progressed to complete respiratory recovery without adverse laryngotracheal sequelae. Otolaryngologists consulted for the airway management of infants with botulism should adopt a conservative approach with meticulous monitoring of endotracheal tube sizes and leak pressures. Tracheotomy is rarely required.