Biology subjects

Nagatomo, Y.

Publications and source records attributed to Nagatomo, Y..

3 recordsLinked to original sources

bioRxiv2021

Deep learning-based chest X-ray age serves as a novel biomarker for cardiovascular aging

Chest X-ray (CXR) is one of the most commonly performed medical imaging tests. Although aging, sex and disease status have been known to cause changes in CXR findings, the extent of these effects has not been fully characterized. Here, we present a deep neural network (DNN) model trained using more than 100,000 CXRs to estimate the patients age and sex solely from CXRs. Our DNN exhibited high performance in terms of estimating age and sex, with Pearsons correlation coefficient between the actual and estimated age of above 0.9 and an area under the ROC curve of 0.98 for sex estimation. The difference between the actual and estimated age is large in CXRs with abnormal findings, suggesting that the estimated age ("CXR age") can be a biomarker for disease status. Furthermore, by applying our DNN to CXRs of consecutive 1,562 hospitalized heart failure patients, we demonstrated that an elevated CXR age is not only associated with aging-related diseases, such as hypertension and atrial fibrillation, but also a worse outcome of heart failure. Given these results, our new concept "CXR age" serves as a novel biomarker for cardiovascular aging and can help clinicians to predict, prevent, and manage cardiovascular diseases.

bioinformatics↗

bioRxiv2020

The IgG3 Subclass of β1-adrenergic receptor autoantibody is an endogenous biaser of β1AR signaling

Autoantibodies recognizing human {beta}1ARs generated due to dysregulation in autoimmune response are generally associated with deleterious cardiac outcomes. However, cellular studies show that isolates of {beta}1AR autoantibody from patients differentially modulate {beta}1AR function. {beta}1AR autoantibodies belong to the IgG class of immunoglobulins, however it is not known whether the IgG sub-classes mediate variability in {beta}1AR responses. To determine whether the IgG3 subclass of {beta}1AR autoantibodies uniquely modulate {beta}1AR function, HEK293 cells stably expressing human {beta}1ARs were utilized. Treatment of cells with IgG3(-) serum resulted in significant increase of cAMP compared to IgG3(+) serum. Pre-treatment of cells with IgG3(+) serum impaired dobutamine-mediated Adenylate Cyclase (AC) activity and cAMP generation whereas, it surprisingly increased AC activity and cAMP generation with {beta}-blocker metoprolol. Consistently, purified IgG3(+) {beta}1AR autoantibodies impaired dobutamine-mediated cAMP while elevating metoprolol-mediated AC activity and cAMP. Despite IgG3(+) autoantibodies reducing cAMP response to dobutamine, they mediate significant ERK activation upon dobutamine. IgG3(+) {beta}1AR autoantibodies did not alter {beta}2AR function, reflecting their specificity. The study shows that IgG3(+) {beta}1AR autoantibody impairs agonist-mediated G-protein coupling while preferentially mediating G-protein-independent ERK activation. Furthermore, it uniquely biases {beta}-blocker towards G-protein coupling. This unique biasing capabilities of IgG3(+) {beta}1AR autoantibodies may underlie the beneficial outcomes in patients.

pharmacology and toxicology↗

bioRxiv2019

Monitoring quinolone resistance due to Haemophilus influenzae mutations (2012-17)

Among drug-resistant bacteria of recent concern, we determined minimum inhibitory concentrations (MICs) of six different quinolone antibacterial agents in Haemophilus influenzae and performed molecular genetic analysis in addition to the exploration for {beta}-lactamase-producing and {beta}-lactamase negative ampicillin-resistant H. influenzae (BLNAR). A total of 144 clinical H. influenzae strains isolated at the Showa University Hospital between 2012 and 2017 were subjected to MIC determination for penicillin/quinolone antibacterial agents using the nitrocefin method and the Clinical and Laboratory Standards Institute broth microdilution method. Moreover, amino acid mutations in the quinolone resistance-determining regions (QRDRs) were analyzed in the isolates showing MIC value of [≥] 0.25 {micro}g/ml of quinolone antibacterial agents. Increasing proportions of BLNAR were noted, with 15% in 2015 to 43.5% in 2016 and 63.6% in 2017. Among quinolone antibacterial agents, all isolates remained susceptible to sitafloxacin (STFX), and STFX showed strong inhibitory potencies against both DNA gyrase and topoisomerase IV. For moxifloxacin (MXF), however, strains with MIC value of 0.5 {micro}g/ml were detected every year since 2013 except 2015. Amino acid mutations were investigated in 17 isolates (11.8%) with MXF MIC value of [≥]0.25 {micro}g/ml, and confirmed in 11 isolates (7.6%), of which mutations of GyrA were found in 9 isolates. Future antibacterial drug regimens may need to address the emergence of quinolone-resistant H. influenzae.

molecular biology↗