To understand the mechanism of muscle remodeling during Xenopus laevis metamorphosis, we examined the in vitro effect of insulin-like growth factor 1 (IGF-1) on growth and differentiation of three different-fate myogenic cell populations: tadpole tail, tadpole dorsal, and young adult leg muscle. IGF-1 promoted growth and differentiation of both tail and leg myogenic cells only under conditions where these cells could proliferate. Inhibition of cell proliferation by DNA synthesis inhibitor cytosine arabinoside completely canceled the IGF-1's cell differentiation promotion, suggesting the possibility that IGF-1's differentiation-promotion effect is an indirect effect via IGF-1's cell proliferation promotion. IGF-1 promoted differentiation dose dependently with maximum effect at 100-500 ng/ml. RT-PCR analysis revealed the upregulation (11-fold) of ifg1 mRNA expression in developing limbs, suggesting that IGF-1 plays a role in promoting muscle differentiation during limb development. The combined effect of triiodo-L-thyronine (T) and IGF-1 was also examined. In adult leg cells, IGF-1 promoted growth and differentiation irrespective of the presence of T. In larval tail cells, cell count was 76% lower in the presence of T, and IGF-1 did not promote proliferation and differentiation in T-containing medium. In larval dorsal cells, cell count was also lower in the presence of T, but IGF-1 enhanced proliferation and differentiation in T-containing medium. This result is likely due to the presence among dorsal cells of both adult and larval types (1:1). Thus, IGF-1 affects only adult-type myogenic cells in the presence of T and helps accelerate dorsal muscle remodeling during metamorphosis.

BACKGROUND AND AIMS In Japan, > 97% of patients with end-stage kidney disease (ESKD) select hemodialysis as a renal replacement therapy (RRT). Hemodialysis (HD) and peritoneal dialysis (PD) have been provided at our hospital for many years, and kidney transplantation (KT) has been available here since 2015. In January 2018, we introduced the option of RRT for outpatients based on the shared decision-making (SDM) method, which was recently shown to be useful for patients. METHOD Patients receive ∼1-h explanation of the SDM method by a nurse in the outpatient department. If patients desire additional outpatient visits, they receive as many as they want; a decision about RRT is not required after a single visit and patients can change their decision at any time. We conducted a prospective observational study to investigate patients’ selection of RRT and the influence of the SDM method on the selection of RRT. The data were examined by Fisher's exact test and significance was accepted at P < 0.05. RESULTS During the period from January 2018 to December 2021, 116 patients visited our outpatient department and 69 patients underwent RRT. Only 53% of the patients initially requested hemodialysis (Figure 1), but > 80% of the patients eventually underwent hemodialysis (Figure 2). From 2018 to 2021, 156 patients started RRT; 58 of them (37%) had visited the outpatient department before starting RRT. The number of patients who visited the outpatient department has increased year by year. The emergency initiation of dialysis decreased significantly after the outpatient use of the SDM method began [odds ratio (OR) 0.44, P = 0.024]. CONCLUSION There was a tendency for patients’ satisfaction regarding their own selection of RRT via the SDM method in the outpatient department. Patients can obtain the information they need and select a better treatment for themselves via an explanation of the SDM method. The SDM method is thus very effective for both patients and medical staff when considering RRT.

Introduction Epstein–Barr virus (EBV) genome is positive not only in B-, but also T- or NK-lymphoid neoplasms: extranodal NK/T-cell lymphoma (ENKL), aggressive NK-cell leukemia, and EBV-positive T- or NK-cell lymphoproliferative disorders (EBV-T/NK-LPDs). EBV-T/NK-LPDs are disorders formerly called chronic active EBV infection presenting sustained inflammation, such as infectious mononucleosis-like symptoms, hypersensitivity to mosquito bites, or hydroa vacciniforme-like eruption accompanied by clonal proliferation of EBV-infected T or NK cells. EBV makes the infected B-cells immortal leading to B-cell lymphomas. However, why and how EBV infects T or NK cells and the mechanism of action responsible for the development of EBV-T/NK-neoplasms has not been elucidated yet. STAT3 is a transactivation factor which mediates proliferation and anti-apoptotic signaling. It was reported that a large variety of primary tumor cells as well as tumor-derived cell lines from patients harbored constitutively activated STAT3. In addition, tyrosine 705 (Y705) of STAT3 was constitutively phosphorylated in ENKL cells (Leukemia, 23, p1667, 2009). Objectives We designed this study to investigate STAT3 activation and its contribution to EBV-T/NK-LPDs development. Materials and Methods EBV-positive T-cell lines, SNT8, SNT15, SNT16, and NK-cell lines, SNK1, SNK6, SNK10, were examined. The EBV-negative T-cell lines HPB-ALL, Jurkat, MOLT4 and peripheral blood mononuclear cells (PBMCs) from healthy donors were used as the negative controls. Clinical samples were obtained from EBV-T/NK-LPDs patients who were diagnosed according to the previously described criteria (Blood, 119, p.673, 2012). To detect and isolate EBV-infected cells, T and NK cells were separated using magnetic beads from PBMCs. STAT3 phosphorylation in EBV-T/NK-LPDs cells were examined in clinical samples and xenograft models of EBV-T/NK-LPDs generated by transplantation of PBMCs from the EBV-T/NK-LPDs patients to NOD/Shi-scid/IL-2Rγnull mice. Mutation of STAT3 was examined by direct sequencing. For in vitro EBV infection, EBV was prepared from the culture medium of B95-8 cells and added to MOLT4 cells (Proc Natl Acad Sci, 100, p7836, 2003). Results First, we investigated the activation of STAT3 in EBV-positive T- or NK-cell lines. Phosphorylation of STAT3 on Y705 and serine 727 (S727) was more clearly detected in comparison with that in EBV-negative cell lines by western blotting under their maintenance condition. STAT3 was localized in the nucleus in the EBV-T/NK-cells. These results indicated STAT3 was constitutively activated in EBV-T/NK-cells. We validated the results in EBV-infected T or NK cells derived from 5 EBV-T/NK-LPDs patients (infected cell types: CD4, 1; CD8, 2; and CD56, 2). Phosphorylation of Y705 and S727 of STAT3 was detected in EBV-infected T or NK cells in them. Immunohistological staining also detected the phosphorylation of EBV-positive cells in the tissue of the xenograft models. In these EBV-T/NK-cells, gene mutation was not identified in SH2 domain of STAT3. Next, we examined the direct effect of EBV on STAT3 activation by in virto EBV infection on MOLT4 cells. Immunofluorescence staining detected that STAT3 moved to the nucleus after the infection. Finally, STAT3 specific inhibitor STA-21 suppressed the proliferation of EBV-T/NK-cells. Conclusions STAT3 is activated by EBV leading to growth promoting effects on EBV-T/NK-LPDs. STAT3 can be an attractive molecular target of the treatment for the disorders. Disclosures No relevant conflicts of interest to declare.