For the purpose of diagnosis of sudden manhood death syndrome, immu- nohistochemical study of ANP was performed in right atria of 10 cases of sudden manhood death syndrome (SMDS) and 10 cases of noncardiac death controls with LSAB-method. It was found that the ANP granulus in right atria of SMDS were obviously depleted, compared with that in the control groups. The results showed that depletion of ANP granules in atria plays an important role in the causes of death of SMDS. This experiment also provides a new approach for studying the causes of SMDS.

Experimental studies on the myocardial ischemia and reperfusion injury in 16 anaethetized SDrats,of which,8 animals were pretreated with morphine(5 mg/kg,i.p.)for preventing of arrhyth-mias,were studied immunocytochemically with anti-muscle actin specific monoclonal antibody (HHF_(35)),8 shan-operated rats were used as control.With HHF_(35) ABC immunocytochemical method,the area of myocardial ischemia and reperfusion injury(without morphine)showed decrease or ab-sence of staining,large areas of staining loss were also seen.In the group with morphine,only smallfoci of staining absence were shown.The myocardium in control animals showed evenly positive stain-ing.No change were seen with HE staining in all groups.The results obtained with HHF_(35) stainingsupport its important value in studying on myocardic reperfusion injury,and indicated that the degreeof myocardic damage may be relative to the arrhythmias in myocardial reperfusion injury.

LIN28 is an RNA binding protein with important roles in early embryo development, stem cell differentiation/reprogramming, tumorigenesis and metabolism. Previous studies have focused mainly on its role in the cytosol where it interacts with Let-7 microRNA precursors or mRNAs, and few have addressed LIN28's role within the nucleus. Here, we show that LIN28 displays dynamic temporal and spatial expression during murine embryo development. Maternal LIN28 expression drops upon exit from the 2-cell stage, and zygotic LIN28 protein is induced at the forming nucleolus during 4-cell to blastocyst stage development, to become dominantly expressed in the cytosol after implantation. In cultured pluripotent stem cells (PSCs), loss of LIN28 led to nucleolar stress and activation of a 2-cell/4-cell-like transcriptional program characterized by the expression of endogenous retrovirus genes. Mechanistically, LIN28 binds to small nucleolar RNAs and rRNA to maintain nucleolar integrity, and its loss leads to nucleolar phase separation defects, ribosomal stress and activation of P53 which in turn binds to and activates 2C transcription factor Dux. LIN28 also resides in a complex containing the nucleolar factor Nucleolin (NCL) and the transcriptional repressor TRIM28, and LIN28 loss leads to reduced occupancy of the NCL/TRIM28 complex on the Dux and rDNA loci, and thus de-repressed Dux and reduced rRNA expression. Lin28 knockout cells with nucleolar stress are more likely to assume a slowly cycling, translationally inert and anabolically inactive state, which is a part of previously unappreciated 2C-like transcriptional program. These findings elucidate novel roles for nucleolar LIN28 in PSCs, and a new mechanism linking 2C program and nucleolar functions in PSCs and early embryo development.
Animals ; Cell Differentiation ; Embryo, Mammalian/metabolism* ; Embryonic Development ; Mice ; Pluripotent Stem Cells/metabolism* ; RNA, Messenger/genetics* ; RNA, Ribosomal ; RNA-Binding Proteins/metabolism* ; Transcription Factors/metabolism* ; Zygote/metabolism*