RESUMEN
CASE PRESENTATION: A woman in her 70s was found unresponsive and brought to our hospital with respiratory distress, cardiomyopathy and volatile alternation between hypotension and hypertension. She was intubated and admitted to intensive care for supportive treatment of suspected baclofen overdose. She gradually recovered and was discharged 10 days after presentation. Laboratory testing confirmed baclofen overdose. CONCLUSION: This case illustrates the classic features of baclofen toxicity but also includes unusual features including ST elevations on ECG and apical ballooning on echocardiogram. Lack of immediate laboratory testing can be a significant diagnostic challenge, so a high index of suspicion is needed to definitively diagnose baclofen overdose. Furthermore, haemodynamic volatility requires careful and frequent re-evaluation of treatment, so early recognition and anticipation of complications are essential for effective management of this life-threatening condition.
Asunto(s)
Baclofeno , Sobredosis de Droga , Humanos , Baclofeno/envenenamiento , Femenino , Sobredosis de Droga/complicaciones , Anciano , Relajantes Musculares Centrales/envenenamiento , Electrocardiografía , EcocardiografíaRESUMEN
Tumorigenesis requires accumulation of genetic and epigenetic alterations, some of which drive tumor initiation. "Oncogene addiction" describes the phenomenon that (1) well-established cancers are dependent on one mutated oncogene or pathway for the maintenance of a malignant phenotype and that (2) withdrawal of the single oncogenic event leads to growth arrest and/or cancer regression. While oncogene addiction has been experimentally validated in advanced tumor models, its role in tumor precursors has not been investigated. We utilized the requirement of Forkhead box A1 (Foxa1) for transcriptional activation of the Upk2-promoter to temporally control the expression of Upk2-HRAS* oncogene, an inducer of urothelial hyperplasia in transgenic mice. Inducible homozygous knockout of Foxa1 in Upk2-HRAS*/UBC-CreERT2/Foxa1loxp/loxp mice results in reduced HRAS* levels. This led to a marked reduction of urothelial proliferation as evidenced by urothelial thinning, degenerative changes such as intracellular vacuole formation, and reduced Ki67 expression. Reduced proliferation did not affect basal, Krt14-positive cells, supporting the fact that Foxa1-regulated Upk2-HRAS* expression occurs primarily in supra-basal cells. Our results indicate that maintenance of urothelial hyperplasia in Upk2-HRAS* mice depends on continuous expression of Foxa1 and activated HRAS, and that mutated receptor tyrosine kinases, FOXA1 and/or other downstream effectors may mediate oncogene addiction in urothelial hyperplasia.
Asunto(s)
Carcinoma de Células Transicionales/genética , Carcinoma de Células Transicionales/patología , Factor Nuclear 3-alfa del Hepatocito/metabolismo , Lesiones Precancerosas/patología , Proteínas Proto-Oncogénicas p21(ras)/genética , Neoplasias de la Vejiga Urinaria/genética , Animales , Carcinogénesis/genética , Proliferación Celular/genética , Modelos Animales de Enfermedad , Regulación Neoplásica de la Expresión Génica , Factor Nuclear 3-alfa del Hepatocito/genética , Humanos , Hiperplasia/genética , Hiperplasia/patología , Ratones , Ratones Noqueados , Ratones Transgénicos , Lesiones Precancerosas/genética , Activación Transcripcional , Vejiga Urinaria/patología , Neoplasias de la Vejiga Urinaria/patología , Urotelio/patologíaRESUMEN
The 5-HT1A receptor is a G protein coupled receptor (GPCR) that activates G proteins of the Gαi/o family. 5-HT1A receptors expressed in the raphe, hippocampus and prefrontal cortex are implicated in the control of mood and are targets for anti-depressant drugs. Regulators of G protein signaling (RGS) proteins are members of a large family that play important roles in signal transduction downstream of G protein coupled receptors (GPCRs). The main role of RGS proteins is to act as GTPase accelerating proteins (GAPs) to dampen or negatively regulate GPCR-mediated signaling. We have shown that a mouse expressing Gαi2 that is insensitive to all RGS protein GAP activity has an anti-depressant-like phenotype due to increased signaling of postsynaptic 5-HT1A receptors, thus implicating the 5-HT1A receptor-Gαi2 complex as an important target. Here we confirm that RGS proteins act as GAPs to regulate signaling to adenylate cyclase and the mitogen-activated protein kinase (MAPK) pathway downstream of the 5-HT1A receptor, using RGS-insensitive Gαi2 protein expressed in C6 cells. We go on to use short hairpin RNA (shRNA) to show that RGS19 is responsible for the GAP activity in C6 cells and also that RGS19 acts as a GAP for 5-HT1A receptor signaling in human neuroblastoma SH-SY5Y cells and primary hippocampal neurons. In addition, in both cell types the synergy between 5-HT1A receptor and the fibroblast growth factor receptor 1 in stimulating the MAPK pathway is enhanced following shRNA reduction of RGS19 expression. Thus RGS19 may be a viable new target for anti-depressant medications.