RESUMO
The existence of a barrier between anesthetic behavioral state transitions has been observed across phyla, but demonstrating that such a barrier exists and is not a pharmacokinetic artifact has not yet been possible in humans. Such an investigation requires temporally precise information regarding the brain concentration of anesthetic in order to demonstrate the specific pharmacokinetic-pharmacodynamic mismatch that is hysteresis. We propose a method to noninvasively determine brain tissue anesthetic concentration using computerized tomography and the radiopaque gaseous anesthetic xenon. Such a technique can be used to investigate pharmacokinetic-pharmacodynamic mismatches in humans.
Assuntos
Anestesia/métodos , Anestésicos Inalatórios/farmacologia , Escala de Avaliação Comportamental , Encéfalo/diagnóstico por imagem , Xenônio/farmacologia , Encéfalo/efeitos dos fármacos , Estado de Consciência/efeitos dos fármacos , Eletroencefalografia/métodos , Voluntários Saudáveis , Humanos , Tomografia Computadorizada por Raios X/métodosRESUMO
Angiopoietin-like proteins (angptls) are capable of ex vivo expansion of mouse and human hematopoietic stem and progenitor cells (HSPCs). Despite this intriguing ability, their mechanism is unknown. In this study, we show that angptl2 overexpression is sufficient to expand definitive HSPCs in zebrafish embryos. Angptl1/2 are required for definitive hematopoiesis and vascular specification of the hemogenic endothelium. The loss-of-function phenotype is reminiscent of the notch mutant mindbomb (mib), and a strong genetic interaction occurs between angptls and notch. Overexpressing angptl2 rescues mib while overexpressing notch rescues angptl1/2 morphants. Gene expression studies in ANGPTL2-stimulated CD34(+) cells showed a strong MYC activation signature and myc overexpression in angptl1/2 morphants or mib restored HSPCs formation. ANGPTL2 can increase NOTCH activation in cultured cells and ANGPTL receptor interacted with NOTCH to regulate NOTCH cleavage. Together our data provide insight to the angptl-mediated notch activation through receptor interaction and subsequent activation of myc targets.
Assuntos
Angiopoietinas/genética , Células-Tronco Hematopoéticas/metabolismo , Receptores Notch/genética , Transdução de Sinais/genética , Proteínas de Peixe-Zebra/genética , Proteína 1 Semelhante a Angiopoietina , Proteína 2 Semelhante a Angiopoietina , Proteínas Semelhantes a Angiopoietina , Angiopoietinas/metabolismo , Animais , Animais Geneticamente Modificados , Western Blotting , Células Cultivadas , Perfilação da Expressão Gênica , Regulação da Expressão Gênica no Desenvolvimento , Técnicas de Silenciamento de Genes , Células HEK293 , Hematopoese/genética , Humanos , Células K562 , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/metabolismo , Camundongos , Microscopia Confocal , Ligação Proteica , Interferência de RNA , Receptores Imunológicos/genética , Receptores Imunológicos/metabolismo , Receptores Notch/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Imagem com Lapso de Tempo , Peixe-Zebra/embriologia , Peixe-Zebra/genética , Peixe-Zebra/metabolismo , Proteínas de Peixe-Zebra/metabolismoRESUMO
BACKGROUND: Individuals with atopic dermatitis (AD) have frequent colonization and infection with Staphylococcus aureus. Rapid elimination of S. aureus depends on constitutive synthesis and mobilization of human beta-defensin-3 (HBD-3). OBJECTIVE: To determine whether keratinocytes in AD, compared with normal, skin are less able to kill S. aureus rapidly, and to assess the potential role that abnormally low mobilization of HBD-3 onto S. aureus has in this process. METHODS: Skin samples from 10 normal individuals and 10 patients with AD were compared for synthesis and mobilization of HBD-3 onto surface-associated S. aureus. Furthermore, keratinocytes from 10 individuals were studied for the effects of T(H)2 cytokines on the ability of the cells to synthesize and mobilize HBD-3, and to kill S. aureus. RESULTS: Keratinocytes in skin biopsies from subjects with AD were defective in killing S. aureus relative to normal individuals (P < .001). The constitutive levels of HBD-3 in the epidermal keratinocytes were similar between normal individuals and those with AD. However, the cells of patients with AD were unable to mobilize HBD-3 efficiently to kill S. aureus. Physiologic Ca(++) was essential for development of normal HBD-3 levels by cultured human keratinocytes. Mobilization of HBD-3 and the ability to kill S. aureus were significantly (P < .05) inhibited by IL-4 and IL-13. Antagonism of IL-4/10/13 with antibodies significantly (P < .01) improved mobilization of HBD-3 onto the surface of S. aureus by skin from patients with AD. CONCLUSION: Patients with AD have problems with S. aureus skin infection. This is a result of increased levels of T(H)2 cytokines, which inhibit keratinocyte mobilization of HBD-3.