Reliability of the step phase detection using inertial measurement units: pilot study

The use of inertial sensors for the gait event detection during a long-distance walking, for example, on different surfaces and with different walking patterns, is important to evaluate the human locomotion. Previous studies demonstrated that gyroscopes on the shank or foot are more reliable than accelerometers and magnetometers for the event detection in case of normal walking. However, these studies did not link the events with the temporal parameters used in the clinical practice; furthermore, they did not clearly verify the optimal position for the sensors depending on walking patterns and surface conditions. The event detection quality of the sensors is compared with video, used as ground truth, according to the parameters proposed by the Gait and Clinical Movement Analysis Society. Additionally, the performance of the sensor on the foot is compared with the one on the shank. The comparison is performed considering both normal walking and deviations to the walking pattern, on different ground surfaces and with or without constraints on movements. The preliminary results show that the proposed methodology allows reliable detection of gait events, even in case of abnormal footfall and in slipping surface conditions, and that the optimal location to place the sensors is the shank

Reconstitution of Mouse Spermatogonial Stem Cell Niches in Culture

SummarySpermatogonial stem cells (SSCs) reside in specific niches within seminiferous tubules. These niches are thought to secrete chemotactic factors for SSCs, because SSCs migrate to them upon transplantation. However, the identity of these chemotactic molecules remains unknown. Here, we established a testis feeder cell culture system and used it to identify SSC chemotactic factors. When seeded on testis cells from infertile mice, SSCs migrated beneath the Sertoli cells and formed colonies with a cobblestone appearance that were very similar to those produced by hematopoietic stem cells. Cultured cells maintained SSC activity and fertility for at least 5 months. Cobblestone colony formation depended on GDNF and CXCL12, and dominant-negative GDNF receptor transfection or CXCL12 receptor deficiency reduced SSC colonization. Moreover, GDNF upregulated CXCL12 receptor expression, and CXCL12 transfection in Sertoli cells increased homing efficiency. Overall, our findings identify GDNF and CXCL12 as SSC chemotactic factors in vitro and in vivo

Discrimination of Stem Cell Status after Subjecting Cynomolgus Monkey Pluripotent Stem Cells to Naïve Conversion

Experimental animal models have played an indispensable role in the development of human induced pluripotent stem cell (iPSC) research. The derivation of high-quality (so-called “true naïve state”) iPSCs of non-human primates enhances their application and safety for human regenerative medicine. Although several attempts have been made to convert human and non-human primate PSCs into a truly naïve state, it is unclear which evaluation methods can discriminate them as being truly naïve. Here we attempted to derive naïve cynomolgus monkey (Cm) (Macaca fascicularis) embryonic stem cells (ESCs) and iPSCs. Several characteristics of naïve Cm ESCs including colony morphology, appearance of naïve-related mRNAs and proteins, leukaemia inhibitory factor dependency, and mitochondrial respiration were confirmed. Next, we generated Cm iPSCs and converted them to a naïve state. Transcriptomic comparison of PSCs with early Cm embryos elucidated the partial achievement (termed naïve-like) of their conversion. When these were subjected to in vitro neural differentiation, enhanced differentiating capacities were observed after naïve-like conversion, but some lines exhibited heterogeneity. The difficulty of achieving contribution to chimeric mouse embryos was also demonstrated. These results suggest that Cm PSCs could ameliorate their in vitro neural differentiation potential even though they could not display true naïve characteristics

Functional Differences between GDNF-Dependent and FGF2-Dependent Mouse Spermatogonial Stem Cell Self-Renewal

精子幹細胞の新しい自己複製様式の発見 -男性不妊症の原因解明、遺伝病の発症機序の理解に期待-. 京都大学プレスリリース. 2015-02-13.Spermatogonial stem cells (SSCs) are required for spermatogenesis. Earlier studies showed that glial cell line-derived neurotrophic factor (GDNF) was indispensable for SSC self-renewal by binding to the GFRA1/RET receptor. Mice with mutations in these molecules showed impaired spermatogenesis, which was attributed to SSC depletion. Here we show that SSCs undergo GDNF-independent self-renewal. A small number of spermatogonia formed colonies when testis fragments from a Ret mutant mouse strain were transplanted into heterologous recipients. Moreover, fibroblast growth factor 2 (FGF2) supplementation enabled in vitro SSC expansion without GDNF. Although GDNF-mediated self-renewal signaling required both AKT and MAP2K1/2, the latter was dispensable in FGF2-mediated self-renewal. FGF2-depleted testes exhibited increased levels of GDNF and were enriched for SSCs, suggesting that the balance between FGF2 and GDNF levels influences SSC self-renewal in vivo. Our results show that SSCs exhibit at least two modes of self-renewal and suggest complexity of SSC regulation in vivo

Current Targeted Therapy for Metastatic Colorectal Cancer

Colorectal cancer (CRC) is the third most common type of cancer and the second leading cause of cancer deaths worldwide. Surgery or surgery plus radiotherapy and/or chemotherapy for patients with metastatic CRC (mCRC) were accepted as the main therapeutic strategies until the early 2000s, when targeted drugs, like cetuximab and bevacizumab, were developed. The use of targeted drugs in clinical practice has significantly increased patients’ overall survival. To date, the emergence of several types of targeted drugs has opened new possibilities and revealed new prospects for mCRC treatment. Therapeutic strategies are continually being updated to select the most suitable targeted drugs based on the results of clinical trials that are currently underway. This review discusses the up-to date molecular evidence of targeted therapy for mCRC and summarizes the Food and Drug Administration-approved targeted drugs including the results of clinical trials. We also explain their mechanisms of action and how these affect the choice of a suitable targeted therapy

Shorter survival in adolescent and young adult patients, compared to adult patients, with stage IV colorectal cancer in Japan

Abstract Background The incidence of colorectal cancer in adolescent and young adult patients is increasing. However, survival and clinical features of young patients, especially those with stage IV disease, relative to adult patients remain unclear. Methods This retrospective single-institution cohort study was conducted at a tertiary care cancer center. Subjects were 861 consecutive patients who were diagnosed with stage IV colorectal cancer at the age of 15 to 74 years and who were referred to the division of surgery or gastrointestinal oncology at the National Cancer Center Hospital from 1999 to 2013. Overall survival (OS) was investigated and clinicopathological variables were analyzed for prognostic significance. Results Of these, 66 (8%) were adolescent and young adult patients and 795 (92%) were adult patients. Median survival time was 13.6 months in adolescent and young adult patients and 22.4 months in adult patients, and 5-year OS rates were 17.3% and 20.3%, respectively, indicating significant worse prognosis of adolescent and young adult patients (p = 0.042). However, age itself was not an independent factor associated with prognosis by multivariate analysis. When compared with adult patients, adolescent and young adult patients consisted of higher proportion of the patients who did not undergo resection of primary tumor, which was an independent factor associated with poor prognosis in multivariate analysis. In patients who did not undergo resection (n = 349), OS of adolescent and young adult patients were significantly worse (p = 0.033). Conclusions Prognoses were worse in adolescent and young adult patients with stage IV colorectal cancer compared to adult patients in Japan, due to a higher proportion of patients who did not undergo resection with more advanced and severe disease, but not due to age itself

Update on Epidemiology, Diagnosis, and Biomarkers in Gastroenteropancreatic Neuroendocrine Neoplasms

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) are a heterogeneous group of malignancies that originate from the diffuse neuroendocrine cell system of the pancreas and gastrointestinal tract and have increasingly increased in number over the decades. GEP-NENs are roughly classified into well-differentiated neuroendocrine tumors and poorly differentiated neuroendocrine carcinomas; it is essential to understand the pathological classification according to the mitotic count and Ki67 proliferation index. In addition, with the advent of molecular-targeted drugs and somatostatin analogs and advances in endoscopic and surgical treatments, the multidisciplinary treatment of GEP-NENs has made great progress. In the management of GEP-NENs, accurate diagnosis is key for the proper selection among these diversified treatment methods. The evaluation of hormone-producing ability, diagnostic imaging, and histological diagnosis is central. Advances in the study of the genetic landscape have led to deeper understanding of tumor biology; it has also become possible to identify druggable mutations and predict therapeutic effects. Liquid biopsy, based on blood mRNA expression for GEP-NENs, has been developed, and is useful not only for early detection but also for assessing minimal residual disease after surgery and prediction of therapeutic effects. This review outlines the updates and future prospects of the epidemiology, diagnosis, and management of GEP-NENs

Utility of circulating tumour DNA for prognosis and prediction of therapeutic effect in locally recurrent rectal cancer: study protocol for a multi-institutional, prospective observational study (JCOG1801A1, CAP-LR study)

Introduction In locally recurrent rectal cancer (LRRC), surgery is a standard treatment for resectable disease. However, short-term and long-term outcomes are unsatisfactory due to the invasive nature of surgical procedures and the high proportion of local recurrence. Consequently, the identification of reliable prognostic and predictive biomarkers to guide treatment decisions may improve outcomes. The presence of circulating tumour DNA (ctDNA) in plasma after surgery may signify the presence of minimal residual disease (MRD) in various cancers. Therefore, we have launched a multi-institutional prospective observational study of ctDNA for MRD detection in conjunction with JCOG1801, a randomised, controlled phase III trial evaluating the efficacy of preoperative chemoradiotherapy (pre-CRT) compared with up-front surgery for LRRC (jRCTs031190076, NCT04288999).Methods and analysis JCOG1801A1 is the first correlative study that assesses ctDNA in LRRC patients enrolled in JCOG1801. Patients randomised to up-front surgery will provide whole blood samples at three time points (prior to surgery, after surgery and after postoperative chemotherapy); those to pre-CRT will provide at five time points (prior to pre-CRT, after pre-CRT, prior to surgery, after surgery and after postoperative chemotherapy). Cell-free DNA will be extracted from plasma and analysed by Guardant Reveal, a tumour tissue–agnostic assay that assesses both genomic alterations and methylation patterns to determine the presence or absence of ctDNA. We will compare the prognosis and treatment response of patients according to their ctDNA status after surgery and at other time points.Ethics and dissemination The study protocol received approval from the Institutional Review Board of National Cancer Center Hospital East on behalf of the participating institutions in February 2023. The study is conducted in accordance with the precepts established in the Declaration of Helsinki and Ethical Guidelines for Medical and Biological Research Involving Human Subjects. Written informed consent will be obtained from all eligible patients prior to registration