Asunto(s)
Enfermería de Práctica Avanzada/legislación & jurisprudencia , Buprenorfina/uso terapéutico , Sustancias Controladas , Equidad en Salud , Trastornos Relacionados con Opioides/tratamiento farmacológico , Política de Salud , Humanos , Concesión de Licencias/clasificación , Concesión de Licencias/estadística & datos numéricos , Tratamiento de Sustitución de Opiáceos , Racismo , Estados UnidosRESUMEN
Across different niches, subsets of highly functional stem cells are maintained in a relatively dormant rather than proliferative state. Our understanding of proliferative dynamics in tissue-specific stem cells during conditions of increased tissue turnover remains limited. Using a TetO-H2B-GFP reporter of proliferative history, we identify skeletal muscle stem cell, or satellite cells, that retain (LRC) or lose (nonLRC) the H2B-GFP label. We show in mice that LRCs and nonLRCs are formed at birth and persist during postnatal growth and adult muscle repair. Functionally, LRCs and nonLRCs are born equivalent and transition during postnatal maturation into distinct and hierarchically organized subsets. Adult LRCs give rise to LRCs and nonLRCs; the former are able to self-renew, whereas the latter are restricted to differentiation. Expression analysis revealed the CIP/KIP family members p21(cip1) (Cdkn1a) and p27(kip1) (Cdkn1b) to be expressed at higher levels in LRCs. In accordance with a crucial role in LRC fate, loss of p27(kip1) promoted proliferation and differentiation of LRCs in vitro and impaired satellite cell self-renewal after muscle injury. By contrast, loss of p21(cip1) only affected nonLRCs, in which myogenic commitment was inhibited. Our results provide evidence that restriction of self-renewal potential to LRCs is established early in life and is maintained during increased tissue turnover through the cell cycle inhibitor p27(kip1). They also reveal the differential role of CIP/KIP family members at discrete steps within the stem cell hierarchy.
Asunto(s)
Inhibidor p27 de las Quinasas Dependientes de la Ciclina/metabolismo , Músculo Esquelético/citología , Coloración y Etiquetado , Células Madre/citología , Células Madre/metabolismo , Animales , Animales Recién Nacidos , Diferenciación Celular , Linaje de la Célula , Proliferación Celular , Inhibidor p21 de las Quinasas Dependientes de la Ciclina/metabolismo , Progresión de la Enfermedad , Proteínas Fluorescentes Verdes/metabolismo , Histonas/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos mdx , Distrofia Muscular Animal/patología , FenotipoRESUMEN
Spontaneous pneumothorax is the most common cause of pneumothorax. We report a case of a 29-year-old healthy woman who presented to the emergency department with a spontaneous pneumothorax caused by a yoga breathing technique called Kapalabhati pranayama, or breath of fire. Yoga breathing exercises are commonly practiced, and a limited number of studies have shown various physiologic benefits of yoga breathing. This is the only known report of spontaneous pneumothorax caused by pranayama, but some other rare causes are noted. This case should illustrate that adverse side effects can occur when one pushes the body to physiologic extremes.