The basis of life-long spermatogenesis is spermatogonial stem cells (SSCs) located at the basal membrane of the seminiferous tubules in the testis. After several rounds of proliferation and spermatogonial differentiat...The basis of life-long spermatogenesis is spermatogonial stem cells (SSCs) located at the basal membrane of the seminiferous tubules in the testis. After several rounds of proliferation and spermatogonial differentiation, the male germ cells will eventually undergo meiosis to form haploid spermatids. Disturbance of the molecular regulation of spermatogenesis can lead to spermatogenic arrest, in humans often during meiosis,1,2 and subsequent azoospermia. Unfortunately, no treatment option enabling conception of a genetically own child is currently available for men suffering from spermatogenic arrest before spermatids are formed.展开更多
Fetal growth restriction(FGR)is the condition in which a fetus does not reach its intrinsic growth potential and in which the shortterm and long-term risks of severe complications are increased.FGR is a frequent compl...Fetal growth restriction(FGR)is the condition in which a fetus does not reach its intrinsic growth potential and in which the shortterm and long-term risks of severe complications are increased.FGR is a frequent complication of pregnancy with a complex etiology and limited management options,other than timely delivery.The most common pathophysiological mechanism is placental insufficiency,due to many underlying causes such as maternal vascular malperfusion,fetal vascular malperfusion and villitis.Identifying truly growth restricted fetuses remains challenging.To date,FGR is often defined by a cut-off of the estimated fetal weight below a certain percentile on a population-based standard.However,small fetal size as a single marker does not discriminate adequately between fetuses or newborns that are constitutionally small but healthy and fetuses or newborns that are growth restricted and thus at risk for adverse outcomes.In 2016,the consensus definition of FGR was internationally accepted to better pinpoint the FGR population.In this review we will discuss the contemporary diagnosis and management issues.Different diagnostic markers are considered,like Doppler measurements,estimated fetal growth,interval growth,fetal movements,biomarkers,and placental markers.展开更多
文摘The basis of life-long spermatogenesis is spermatogonial stem cells (SSCs) located at the basal membrane of the seminiferous tubules in the testis. After several rounds of proliferation and spermatogonial differentiation, the male germ cells will eventually undergo meiosis to form haploid spermatids. Disturbance of the molecular regulation of spermatogenesis can lead to spermatogenic arrest, in humans often during meiosis,1,2 and subsequent azoospermia. Unfortunately, no treatment option enabling conception of a genetically own child is currently available for men suffering from spermatogenic arrest before spermatids are formed.
文摘Fetal growth restriction(FGR)is the condition in which a fetus does not reach its intrinsic growth potential and in which the shortterm and long-term risks of severe complications are increased.FGR is a frequent complication of pregnancy with a complex etiology and limited management options,other than timely delivery.The most common pathophysiological mechanism is placental insufficiency,due to many underlying causes such as maternal vascular malperfusion,fetal vascular malperfusion and villitis.Identifying truly growth restricted fetuses remains challenging.To date,FGR is often defined by a cut-off of the estimated fetal weight below a certain percentile on a population-based standard.However,small fetal size as a single marker does not discriminate adequately between fetuses or newborns that are constitutionally small but healthy and fetuses or newborns that are growth restricted and thus at risk for adverse outcomes.In 2016,the consensus definition of FGR was internationally accepted to better pinpoint the FGR population.In this review we will discuss the contemporary diagnosis and management issues.Different diagnostic markers are considered,like Doppler measurements,estimated fetal growth,interval growth,fetal movements,biomarkers,and placental markers.
