Trans men can achieve adequate muscular development through low-dose testosterone therapy: A long-term study on body composition changes.

BACKGROUND: Transgender individuals undergo the gender-affirming hormone therapy (GAHT) to achieve physical changes consistent with their gender identity. Few studies are available on the long-term safety and efficacy of GAHT. OBJECTIVES: To investigate the long-term physical effects and the safety of the testosterone therapy for trans men and to assess the impact of differential hormone dose. MATERIALS AND METHODS: Trans men who initiated GAHT between May 2000 and December 2021 were included in this retrospective analysis. Physical findings (body mass index, body fat percentage (BFP), lean body mass (LBM), and grip strength), blood testing results (hemoglobin, hematocrit, uric acid, creatinine, total cholesterol, triglycerides, and total testosterone), and menstrual cessation were recorded. We assessed the effects of testosterone on body composition changes and laboratory parameters, comparing a low-dose group (≤ 62.5 mg/wk) to a high-dose group (> 62.5 mg/wk). RESULTS: Of 291 participants, 188 patients (64.6%) were in the low-dose group and 103 (35.4%) in the high-dose group. Cumulative menstrual cessation rates up to 12 months were not significantly different between groups. Both groups showed a decrease in BFP and an increase in LBM during the first year of therapy, followed by a slight increase in both over the long term. The high-dose group exhibited greater LBM gains during the first year. Higher hormone doses and lower initial LBM values were associated with LBM increases at 3 and 6 months (3 mo, P = 0.006, P < 0.001; 6 mo, P = 0.015, P < 0.001). There were no long-term, dose-dependent side effects such as polycythemia or dyslipidemia. CONCLUSION: Long-term GAHT for trans men is safe and effective. Low-dose testosterone administration is sufficient to increase LBM in trans men. Higher testosterone doses can lead to an earlier increase in muscle mass.

Linearly Polarized Coherent Emission from Relativistic Magnetized Ion-Electron Shocks.

Fast radio bursts (FRBs) are millisecond transient astrophysical phenomena and bright at radio frequencies. The emission mechanism, however, remains unsolved yet. One scenario is a coherent emission associated with the magnetar flares and resulting relativistic shock waves. Here, we report unprecedentedly large-scale simulations of relativistic magnetized ion-electron shocks, showing that strongly linear-polarized electromagnetic waves are excited. The kinetic energy conversion to the emission is so efficient that the wave amplitude is responsible for the brightness. We also find a polarization angle swing reflecting shock front modulation, implicating the polarization property of some repeating FRBs. The results support the shock scenario as an origin of the FRBs.

Mice Recognise Mice in Neighbouring Rearing Cages and Change Their Social Behaviour.

Mice are social animals that change their behaviour primarily in response to visual, olfactory, and auditory information from conspecifics. Rearing conditions such as cage size and colour are important factors influencing mouse behaviour. In recent years, transparent plastic cages have become standard breeding cages. The advantage of using a transparent cage is that the experimenter can observe the mouse from outside the cage without touching the cage. However, mice may recognise the environment outside the cage and change their behaviour. We speculated that mice housed in transparent cages might recognise mice in neighbouring cages. We used only male mice in this experiment. C57BL/6 mice were kept in transparent rearing cages with open lids, and the cage positions were maintained for 3 weeks. Subsequently, we examined how mice behaved toward cagemate mice, mice from neighbouring cages, and mice from distant cages. We compared the level of interest in mice using a social preference test. Similar to previous reports, subject mice showed a high degree of interest in unfamiliar mice from distant cages. By contrast, subject mice reacted to mice from neighbouring cages as familiar mice, similar to cagemate mice. This suggests that mice housed in transparent cages with open lids perceive the external environment and identify mice in neighbouring cages. Researchers should pay attention to the environment outside the mouse cage, especially for the social preference test.

Effects of home-cage elevation on behavioral tests in mice.

BACKGROUND: Research reproducibility is a common problem in preclinical behavioral science. Mice are an important animal model for studying human behavioral disorders. Experimenters, processing methods, and rearing environments are the main causes of data variability in behavioral neuroscience. It is likely that mice adapt their behavior according to the environment outside the breeding cage. We speculated that mice housed on elevated shelves and mice housed on low shelves might have differently altered anxiety-like behavior toward heights. PURPOSE: The purpose of this study was to investigate potential behavioral changes in mice raised at different heights for 3 weeks. Changes in behavior were examined using various experimental tests. RESULTS: Mice housed on elevated shelves showed reduced anxiety-like behavior in a light/dark traffic test compared with mice housed on low shelves. There were no significant differences between the two groups in terms of activity, exploratory behavior, muscle strength, or depression-like behavior. CONCLUSIONS: Our results indicate that different cage heights and corresponding light exposure may alter the anxiety-like behavior of mice in response to brightness. Researchers need to carefully control the cage height and light intensity experienced by the mice to produce reproducible test results.

Comprehensive behavioral study of C57BL/6.KOR-ApoEshl mice.

Background: Apolipoprotein E (ApoE) is associated with Alzheimer's disease (AD) and cognitive dysfunction in elderly individuals. There have been extensive studies on behavioral abnormalities in ApoE-deficient (Apoeshl) mice, which have been described as AD mouse models. Spontaneously hyperlipidemic mice were discovered in 1999 as ApoE-deficient mice due to ApoE gene mutations. However, behavioral abnormalities in commercially available Apoeshl mice remain unclear. Accordingly, we aimed to investigate the behavioral abnormalities of Apoeshl mice. Results: Apoeshl mice showed decreased motor skill learning and increased anxiety-like behavior toward heights. Apoeshl mice did not show abnormal behavior in the Y-maze test, open-field test, light/dark transition test, and passive avoidance test. Conclusion: Our findings suggest the utility of Apoeshl mice in investigating the function of ApoE in the central nervous system.

Semi-enzymatic acceleration of oxidative protein folding by N-methylated heteroaromatic thiols.

We report the first example of a synthetic thiol-based compound that promotes oxidative protein folding upon 1-equivalent loading to the disulfide bonds in the client protein to afford the native form in over 70% yield. N-Methylation is a central post-translational processing of proteins in vivo for regulating functions including chaperone activities. Despite the universally observed biochemical reactions in nature, N-methylation has hardly been utilized in the design, functionalization, and switching of synthetic bioregulatory agents, particularly folding promotors. As a biomimetic approach, we developed pyridinylmethanethiols to investigate the effects of N-methylation on the promotion of oxidative protein folding. For a comprehensive study on the geometrical effects, constitutional isomers of pyridinylmethanethiols with ortho-, meta-, and para-substitutions have been synthesized. Among the constitutional isomers, para-substituted pyridinylmethanethiol showed the fastest disulfide-bond formation of the client proteins to afford the native forms most efficiently. N-Methylation drastically increased the acidity and enhanced the oxidizability of the thiol groups in the pyridinylmethanethiols to enhance the folding promotion efficiencies. Among the isomers, para-substituted N-methylated pyridinylmethanethiol accelerated the oxidative protein folding reactions with the highest efficiency, allowing for protein folding promotion by 1-equivalent loading as a semi-enzymatic activity. This study will offer a novel bioinspired molecular design of synthetic biofunctional agents that are semi-enzymatically effective for the promotion of oxidative protein folding including biopharmaceuticals such as insulin in vitro by minimum loading.

Component-specific reduction in perineuronal nets in senescence-accelerated mouse strains.

With increased life expectancy, age-related diseases are a significant health concern in Western societies. Animal models (e.g., rodents) have been used to understand age-related changes in brain function-particularly through the senescence-accelerated mouse (SAM) strain. Previous reports have shown that the senescence-accelerated mouse propensity (SAMP)8 and SAMP10 strains have learning disabilities. In this study, we analyzed the prefrontal cortex, which is involved in cognitive function. We aimed to clarify the changes in parvalbumin-positive interneurons (PV-positive neurons), which are related to cognitive function, and perineuronal nets (PNNs), which are special extracellular matrix molecules formed around them. We performed histological analysis of PV-positive neurons and PNNs in the prefrontal cortex to elucidate the mechanism of behavioral abnormalities in SAMP8 and SAMP10 strains. Expression of Cat-315-positive PNN was not confirmed in the prefrontal cortex of SAMP10 mice. However, the density of AB1031-positive PNN, tenascin-R-positive PNN, and brevican-positive PNN decreased in the prefrontal cortex of SAMP8 and SAMP10 mice compared to that of the senescence-accelerated mouse resistance (SAMR1) mice. In addition, the density of PV-positive neurons was lower in SAMP8 mice than in SAMR1 mice. These mice, which exhibited behavioral and neuropathological phenotypes with age, showed different PV-positive neurons and PNNs in the prefrontal cortex compared with the SAMR1 mice. We believe that the results of this study will be useful for elucidating the mechanisms of age-related decline in cognitive and learning functions using SAM.

Comorbid psychiatric disorders and long-term survival after liver transplantation in transplant facilities with a psychiatric consultation-liaison team: a multicenter retrospective study.

OBJECTIVE: Comorbid psychiatric disorders negatively affect the survival rate of patients with some physical disorders. In liver transplant recipients, various psychiatric disorders have been identified as worsening prognosis. However, little is known about how the presence of any comorbid (overall) disorders affect the survival rate of transplant recipients. In this study, we examined the effect of overall comorbid psychiatric disorders on survival rate in liver transplant recipients. METHODS: A total of 1006 recipients who underwent liver transplantation between September 1997 and July 2017 across eight transplant facilities with a psychiatric consultation-liaison team were identified consecutively. Recipients were categorized into those with comorbid psychiatric disorders and those without comorbid psychiatric disorders. In the comorbid psychiatric disorder group, psychiatric disorder diagnosis and time of diagnosis were investigated retrospectively. RESULTS: Of the 1006 recipients, 294 (29.2%) had comorbid psychiatric disorders. Comorbid psychiatric disorders in the 1006 recipients were insomnia (N = 107, 10.6%), delirium (N = 103, 10.2%), major depressive disorder (N = 41, 4.1%), adjustment disorder (N = 19, 1.9%), anxiety disorder (N = 17, 1.7%), intellectual disability (N = 11, 1.1%), autism spectrum disorder (N = 7, 0.7%), somatic symptom disorder (N = 4, 0.4%) schizophrenia (N = 4, 0.4%), substance use disorder (N = 24, 2.4%) and personality disorder (N = 2, 0.2%). The most common time of psychiatric disorder diagnosis was within the first 3 months after liver transplantation (51.6%). The final mortality in patients with comorbid psychiatric disorder diagnosis during the five periods (pretransplant, transplant to 3 months, months to 1 year, 1 to 3 years, and over 3 years posttransplant) was 16.2%, 18.8%, 39.1%, 28.6%, and 16.2% respectively, and there were no significant differences between the five periods (χ2 = 8.05, df = 4, p = 0.09). Overall comorbid psychiatric disorders were significantly associated with shorter survival time (log-rank test: p = 0.01, hazard ratio: 1.59 [95% confidence interval: 1.14-2.21], survival rate at the endpoint [%]: 62.0 vs. 83.3). However, after adjusting for confounding variables using Cox proportional hazards regression, there was no significant effect of overall comorbid psychiatric disorders on prognosis. CONCLUSION: Comorbid psychiatric disorders did not affect the survival rate of liver transplant recipients in this study.

The prevention of home-cage grid climbing affects muscle strength in mice.

Experimenters and treatment methods are the major contributors to data variability in behavioral neuroscience. However, home cage characteristics are likely associated with data variability. Mice housed in breeding cages spontaneously exhibit behavioral patterns such as biting into the wire grid and climbing on the grid lid. We aimed to clarify the effect of covering the stainless steel wire grid lid in commonly used home cage with Plexiglas to prevent climbing on muscle strength in mice. Furthermore, we investigated the effects of climbing prevention on activity and anxiety-like behavior, and the impact of climbing prevention during the postnatal development period and adulthood on muscle strength. Muscle strength, anxiety-like behavior, and locomotor activity were assessed by a battery of tests (wire hang, suspension, grip strength, rotarod, elevated-plus maze, and open field tests). Mice prevented from climbing the wire grid during postnatal development displayed lower muscle strength than those able to climb. Moreover, mice prevented from climbing for 3 weeks following maturity had weakened muscles. The muscle strength was decreased with 3 weeks of climbing prevention in even 1-year-old mice. In summary, the stainless steel wire grid in the home cage contributed to the development and maintenance of muscle strength in mice.

Serum Albumin Levels Strongly Predict Survival Outcome of Elderly Patients with Diffuse Large B-Cell Lymphoma Treated with Rituximab-Combined Chemotherapy.

Background: In the current Japanese aging society, a high number of very elderly patients (age ranged from 80 to 93) with diffuse large B-cell lymphoma (DLBCL, most frequent hematological malignancy), who require chemotherapy are encountered. However, standard chemotherapy can result in severe adverse effects in elderly patients. Although various scoring systems are available to assess frailty, they are too complicated to immediately make a therapeutic decision, and studies on indications for chemotherapy in elderly patients are few. Materials and Methods: In the present study, we retrospectively analyzed the clinical records of 56 patients with DLBCL aged 80 or older who received R-CHOP or similar chemotherapy. Association of various clinical parameters, including performance status, stage, B symptom(s), laboratory data and relative dose intensity and survival outcomes was examined. Results: Pretreatment serum albumin level was identified as the only factor that predicts overall and progression-free survivals. Conclusion: We have concluded that very elderly DLBCL patients aged 80 or older with hypoalbuminemia may be unfit for standard chemotherapy, regardless of other factors. Alternative or palliative therapy should be considered for those patients.

Detection of secondary upper gastrointestinal tract cancer during follow-up esophagogastroduodenoscopy after gastrectomy for gastric cancer.

Aim: Esophagogastroduodenoscopy (EGD) may contribute to early detection of secondary cancer in the upper gastrointestinal tract although the clinical relevance of follow-up after gastrectomy remains unclear. This study aimed to elucidate the effectiveness of follow-up EGD by investigating the incidence of secondary cancer in any part of the upper gastrointestinal tract. Methods: Data from 1438 patients who underwent curative partial gastrectomy for primary gastric cancer between 2008 and 2014 and follow-up EGD at least once during a 5-year follow-up period were retrospectively reviewed. Incidence rates of remnant gastric cancer, laryngeal cancer, and esophageal cancer detected after follow-up EGD were determined, and risk factors for secondary cancers were examined. The characteristics of clinicopathological diagnoses of secondary cancers were reviewed and compared according to the frequency of follow-up EGD. Results: The average annual frequency of EGD was 0.7, while the 5-year cumulative incidence rates of remnant gastric cancer and secondary laryngeal and esophageal cancers were 2.9% and 1.3%, respectively. Risk factors for remnant gastric cancer included heavy smoking, proximal gastrectomy, and tumor size ≥ 30 mm. All secondary cancers were resectable upon diagnosis, with endoscopically resectable cancer accounting for 81.0% of cases. Our results found a significantly higher proportion of endoscopically resectable cancers during regular follow-up than during infrequent follow-up. Conclusions: Follow-up EGD can be a useful modality for detecting secondary upper gastrointestinal tract cancer, likely leading to curative treatment for secondary cancer. Focusing on patients presenting with risk factors may increase the value of follow-up EGD after gastrectomy.

Characteristic DNA methylation profiles of chorionic villi in recurrent miscarriage.

Dysregulation of transcriptional programs that are tightly regulated by DNA methylation during placental and fetal development at different gestational stages, may cause recurrent miscarriage. Here, we examined genome-wide DNA methylation in chorionic villi and decidual tissues from patients suffering RM and from healthy women who had undergone artificial abortion (n = 5 each). We found that 13,426 and 5816 CpG sites were differentially methylated in chorionic villi and decidua, respectively. DNA methylation profiles of chorionic villi, but not decidua, in RM patients was clearly distinct from AA controls. Among the differentially methylated genes, the enhancer region of SPATS2L was significantly more highly methylated in RM patients (n = 19) than AA controls (n = 19; mean methylation level, 52.0%-vs.-28.9%, P < 0.001), resulting in reduced expression of SPATS2L protein in the former. Functionally, depletion of SPATS2L in extravillous trophoblast cells decreased their invasion and migration abilities. Our data indicate that particularly the chorionic villi in RM patients exhibit distinct DNA methylation profiles compared with normal pregnancies and that this changed DNA methylation status may impede the progression of embryo development via the altered expression of genes such as SPATS2L in the villi.

Effect of simultaneous testing of two mice in the tail suspension test and forced swim test.

In mouse studies, the results of behavioural experiments are greatly affected by differences in the experimental environment and handling methods. The Porsolt forced swim test and tail suspension test are widely used to evaluate predictive models of depression-like behaviour in mice. It has not been clarified how the results of these tests are affected by testing single or multiple mice simultaneously. Therefore, this study evaluated the differences between testing two mice simultaneously or separately. To investigate the effect of testing multiple mice simultaneously, the Porsolt forced swim test and tail suspension test were performed in three patterns: (1) testing with an opaque partition between two mice, (2) testing without a partition between two mice, and (3) testing a single mouse. In the Porsolt forced swim test, the mice tested simultaneously without a partition demonstrated increased immobility time as compared to mice tested alone. No difference in immobility time was observed between the three groups in the tail suspension test. Our results showed that the environment of behavioural experiments investigating depression-like behaviour in mice can cause a difference in depression-like behaviour. The results of this experiment indicated that it is necessary to describe the method used for behavioural testing in detail.

Prevalence of Gender Dysphoria by Gender and Age in Japan: A Population-Based Internet Survey Using the Utrecht Gender Dysphoria Scale.

BACKGROUND: Several studies have attempted to estimate the prevalence of gender dysphoria (GD) from a general population sample. However, no previous studies used reliable questionnaires. AIM: To estimate the prevalence of GD in Japan by gender and age using the Utrecht Gender Dysphoria Scale (UGDS). METHODS: A cross-sectional observational study was conducted with 20,000 respondents between the ages of 20 and 69 who were registered with an internet research company. The study consisted of two phases. First, the participants were asked to self-identify their gender on two 5-point Likert scales. Second, the screened participants completed the UGDS. OUTCOMES: Self-identified gender and GD were defined as follows: ambivalent gender (equally feeling like the birth gender and another gender), incongruent gender (a stronger sense of the latter vs the former), narrow GD (incongruent gender + UGDS score ≥ 41), and broad GD (ambivalent or incongruent gender + UGDS score ≥ 41). RESULTS: Among the eligible participants, the age-adjusted proportions of those classified as male (n = 7827) and female (n = 8903) at birth were 6.0% and 5.9%, respectively, for ambivalent gender, and 0.93% and 1.0%, respectively, for incongruent gender. The age-adjusted prevalence of GD was 0.27% (95% confidence interval, 0.18-0.42) and 0.35% (95% confidence interval, 0.25-0.50) for narrow GD and 0.87% (95% confidence interval, 0.69-1.1) and 1.1% (95% confidence interval, 0.86-1.3) for broad GD, respectively. No significant gender differences were found within the age groups, except for broad GD in respondents in their 50s (P = .016). However, for both genders, significant differences were found between age groups such that GD was more prevalent in younger vs older respondents, except for broad GD in respondents classified as female at birth (P = .063). CLINICAL IMPLICATIONS: Clinicians should be aware that the prevalence of GD is not negligible and that it varies with age. GD should be assessed in detail from various perspectives in addition to self-identified gender. STRENGTHS & LIMITATIONS: This study used a reliable questionnaire to examine the prevalence of GD in a large population. However, the participants did not represent the general population because this was an internet survey. CONCLUSION: The prevalence of GD was much higher than previously estimated by clinic-based studies, and was more frequently associated with participant age vs gender. Oshima Y, Matsumoto Y, Terada S, et al. Prevalence of Gender Dysphoria by Gender and Age in Japan: A Population-based Internet Survey Using the Utrecht Gender Dysphoria Scale. J Sex Med 2022;19:1185-1195.

Anisotropy-driven quantum criticality in an intermediate valence system.

Intermetallic compounds containing f-electron elements have been prototypical materials for investigating strong electron correlations and quantum criticality (QC). Their heavy fermion ground state evoked by the magnetic f-electrons is susceptible to the onset of quantum phases, such as magnetism or superconductivity, due to the enhanced effective mass (m*) and a corresponding decrease of the Fermi temperature. However, the presence of f-electron valence fluctuations to a non-magnetic state is regarded an anathema to QC, as it usually generates a paramagnetic Fermi-liquid state with quasiparticles of moderate m*. Such systems are typically isotropic, with a characteristic energy scale T0 of the order of hundreds of kelvins that require large magnetic fields or pressures to promote a valence or magnetic instability. Here we show the discovery of a quantum critical behaviour and a Lifshitz transition under low magnetic field in an intermediate valence compound α-YbAlB4. The QC origin is attributed to the anisotropic hybridization between the conduction and localized f-electrons. These findings suggest a new route to bypass the large valence energy scale in developing the QC.

Mice can recognise water depths and will avoid entering deep water.

Rodents are averse to bodies of water, and this aversion has been exploited in experiments designed to study stress in mice. However, a few studies have elucidated the characteristics of murine water aversion. In this study, we investigated how mice behave in and around areas filled with water. Using variants of the open field test that contained pools of water at corners or sides of the field, we recorded the movements of mice throughout the field under various conditions. When the water was 8 mm deep, the mice explored the water pool regardless of whether an object was placed within it, but when the water was 20 mm deep, the mice were less willing to enter it. When the mice were placed on a dry area surrounded by 3 mm-deep water, they explored the water, but when they were surrounded by 8 mm-deep water, they stayed within the dry area. Our results indicate that mice exhibit exploratory behaviours around water, they can recognise water depths and avoid unacceptably deep water, and their willingness to enter water may be reduced by situational anxiety. Our experimental method could be used to investigate water-related anxiety-like behaviours in mice.

Chronic Inhibition of Aggressive Behavior Induces Behavioral Change in Mice.

Suppression of anger is more common than its expression among Asian individuals. Emotional suppression is considered an unhealthy emotional regulation. Most studies on emotional suppression have concluded that suppression adversely affects social outcomes, with approximately 5% of the world's population suffering from emotional disorders. However, anger suppression has not received academic attention, and details of the effects of chronic anger suppression on the central nervous system remain unclear. In this study, we performed the resident-intruder test to investigate the effect of chronic suppression of aggressive behavior in mice using a behavioral test battery and to clarify whether suppression of this aggressive behavior is stressful for mice. Mice chronically inhibited aggressive behavior and lost weight. Mice with inhibited aggressive behavior showed a reduced percentage of immobility time during the tail suspension test as well as no changes in activity, anxiety-like behavior, muscle strength, or temperature sensitivity. This study provides scientific evidence for the effects of chronic aggressive behavior inhibition on the body and central nervous system.

Fingolimod increases parvalbumin-positive neurons in adult mice.

In recent years, it has been shown that central nervous system agents, such as antidepressants and antiepileptic drugs, reopen a critical period in mature animals. Fingolimod, which is used for the treatment of multiple sclerosis, also restores neuroplasticity. In this study, we investigated the effects of parvalbumin (PV)-positive neurons and perineuronal nets (PNN) on fingolimod administration with respect to neuroplasticity. Fingolimod was chronically administered intraperitoneally to mature mice. PV-positive neurons and PNN in the hippocampus, prefrontal cortex, and somatosensory cortex were analyzed. An increase in PV-positive neurons was observed in the hippocampus, prefrontal cortex, and somatosensory cortex of the fingolimod-treated mice. An increase in Wisteria floribunda agglutinin-positive PNN was confirmed in mice treated with fingolimod in the somatosensory cortex only. Fingolimod increased the density of PV-positive neurons in the brains of mature mice. The results indicate that fingolimod may change the critical period in mature animals.

Successful treatment of paraneoplastic pemphigus and bronchiolitis obliterans associated with follicular lymphoma with obinutuzumab and bendamustine.

We herein report the rare case of a 72-year-old female who presented with paraneoplastic pemphigus (PNP) and bronchiolitis obliterans (BO) associated with follicular lymphoma (FL), who was successfully treated with obinutuzumab (GA101; G) and bendamustine (B). The patient had severe erosive stomatitis and bilateral conjunctival hyperemia that persisted for more than 6 months. A huge mass was found in the abdominal cavity, and a biopsy revealed grade 1 FL (stage IV). Based on a lip biopsy result, the patient was diagnosed with PNP associated FL. The patient received bendamustine and obinutuzumab (BG) chemotherapy and FL and PNP responded very well, but BO was additionally associated during the course of BG. BO progressed without exacerbation as BG therapy progressed to a 2 year maintenance therapy with G, and combination of azithromycin, inhaled bronchodilator therapy, and corticosteroid. She was followed up at the outpatient department with no pulmonary function decline or FL and PNP recurrence. Our case suggests that BG could be a promising treatment option for PNP and BO.

Evaluation of artificial intelligence using time-lapse images of IVF embryos to predict live birth.

RESEARCH QUESTION: Can artificial intelligence (AI) improve the prediction of live births based on embryo images? DESIGN: The AI system was created by using the Attention Branch Network associated with deep learning to predict the probability of live birth from 141,444 images recorded by time-lapse imaging of 470 transferred embryos, of which 91 resulted in live birth and 379 resulted in non-live birth that included implantation failure, biochemical pregnancy and clinical miscarriage. The possibility that the calculated confidence scores of each embryo and the focused areas visualized in each embryo image can help predict subsequent live birth was examined. RESULTS: The AI system for the first time successfully visualized embryo features in focused areas that had potential to distinguish between live and non-live births. No visual feature of embryos were visualized that were associated with live or non-live births, although there were many images in which high-focused areas existed around the zona pellucida. When a cut-off level for the confidence score was set at 0.341, the live birth rate was significantly greater for embryos with a score higher than the cut-off level than for those with a score lower than the cut-off level (P < 0.001). In addition, the live birth rate of embryos with good morphological quality and confidence scores higher than 0.341 was 41.1%. CONCLUSIONS: The authors have created an AI system with a confidence score that is useful for non-invasive selection of embryos that could result in live birth. Further study is necessary to improve selection accuracy.