Refined prefrontal working memory network as a neuromarker for Alzheimer’s disease

Detecting Alzheimer’s disease (AD) is an important step in preventing pathological brain damage. Working memory (WM)-related network modulation can be a pathological feature of AD, but is usually modulated by untargeted cognitive processes and individual variance, resulting in the concealment of this key information. Therefore, in this study, we comprehensively investigated a new neuromarker, named “refined network,” in a prefrontal cortex (PFC) that revealed the pathological features of AD. A refined network was acquired by removing unnecessary variance from the WM-related network. By using a functional near-infrared spectroscopy (fNIRS) device, we evaluated the reliability of the refined network, which was identified from the three groups classified by AD progression: healthy people (N=31), mild cognitive impairment (N=11), and patients with AD (N=18). As a result, we identified edges with significant correlations between cognitive functions and groups in the dorsolateral PFC. Moreover, the refined network achieved a significantly correlating metric with neuropsychological test scores, and a remarkable three-class classification accuracy (95.0%). These results implicate the refined PFC WM-related network as a powerful neuromarker for AD screening.     

Detection of Rotator Cuff Tears by Ultrasound: How Many Scans Do Novices Need to Be Competent?

BackgroundUltrasound is commonly used for evaluating rotator cuff tears. However, little training in ultrasound imaging is provided during orthopedic residents’ training period. Therefore, we performed this study to determine how many ultrasound scans are required for orthopedic residents to be competent and self-confident in the diagnosis of supraspinatus tendon tears and to investigate whether senior residents outperformed junior residents.MethodsWe studied two third-year residents who had no previous experience of shoulder ultrasound and evaluated their ability to detect rotator cuff pathologies. Their learning curves were plotted using a cumulative summation analysis with a 20% acceptable failure rate compared to arthroscopic findings. Downward, upward, and horizontal cumulative summation trends indicated incompetence, exceptional competence, and competence, respectively. The diagnostic accuracy of third-year residents was compared with that of second-year residents and the number of cases required to gain self-confidence was evaluated.ResultsCumulative summation analysis showed that after 26–28 scans, residents achieved the competence to correctly diagnose supraspinatus tears: an upward trend was observed from the beginning for full-thickness tears and a downward trend was observed for partial-thickness tears. Sensitivity and specificity were 0.95 and 0.79, respectively, for third-year residents and 0.91 and 0.58, respectively, for second-year residents. Residents reported self-confidence after 30 ultrasound scans for the detection of rotator cuff tears.ConclusionsThe number of scans that novices needed to be competent for detecting rotator cuff tears was approximately 30 cases, and the diagnostic accuracy of third-year residents was significantly higher than that of second-year residents.     

Relationship between Dietary Habits and Control of Lipid Profiles in Patients with Dyslipidemia Using Pravastatin

We investigated the association between dietary habits, evaluated using the modified Mini Dietary Assessment Index for Koreans (MDA), and lipid control among patients aged ≥20 years who had used pravastatin for dyslipidemia for 6 months. Participants were administered questionnaires regarding sociodemographic characteristics and lifestyle factors. Odds ratios and 95% confidence intervals for the control of low-density lipoprotein cholesterol (LDL-C), triglyceride (TG), and total cholesterol (TC) at 6 months for each category of the modified MDA items were calculated through multivariate logistic regression analysis. The odds for controlled LDL-C was higher among those who consumed cholesterol-rich foods <1 time/week (3.27, 1.25–8.57) than for those who did so ≥4 times/week. The odds for controlled TG was higher among those who always consumed dairy products (2.96, 1.36–6.44), ate protein-rich foods three times/day (2.94, 1.06–8.10), and had a regular eating schedule (3.02, 1.30–7.00) than among those who did not have any of these. The odds for controlled TC was higher among those with a regular eating schedule (3.47, 1.55–7.76) than among their counterparts. Patients with dyslipidemia should consume less cholesterols, consume more dairy and protein-rich foods, and follow a regular eating schedule to control lipid profiles.     

Ssu72 phosphatase directly binds to ZAP-70, thereby providing fine-tuning of TCR signaling and preventing spontaneous inflammation

ZAP-70 is required for the initiation of T cell receptor (TCR) signaling, and Ssu72 is a phosphatase that regulates RNA polymerase II activity in the nucleus. However, the mechanism by which ZAP-70 regulates the fine-tuning of TCR signaling remains elusive. Here, we found that Ssu72 contributed to the fine-tuning of TCR signaling by acting as tyrosine phosphatase for ZAP-70. Affinity purification–mass spectrometry and an in vitro assay demonstrated specific interaction between Ssu72 and ZAP-70 in T cells. Upon TCR stimulation, Ssu72-deficient T cells increased the phosphorylation of ZAP-70 and downstream molecules and exhibited hyperresponsiveness, which was restored by reducing ZAP-70 phosphorylation. In vitro assay demonstrated that recombinant Ssu72 reduced tyrosine phosphorylation of ZAP-70 via phosphatase activity. Cd4-CreSsu72^fl/fl mice showed a defect in the thymic development of invariant natural killer T cells and reductions in CD4⁺ and CD8⁺ T cell numbers in the periphery but more CD44^hiCD62L^lo memory T cells and fewer CD44^loCD62L^hi naïve T cells, compared with wild-type mice. Furthermore, Cd4-CreSsu72^fl/fl mice developed spontaneous inflammation at 6 mo. In conclusion, Ssu72 phosphatase regulates the fine-tuning of TCR signaling by binding to ZAP-70 and regulating its tyrosine phosphorylation, thereby preventing spontaneous inflammation.

Ssu72 phosphatase regulates the recycling of RNA polymerase II by binding to the C-terminal domain (CTD) of RNA polymerase II and inhibiting the phosphorylation of serine and tyrosine residues in the CTDs in yeast and mammalian cells (1, 2). Recently, Ssu72 phosphatase was found to regulate the cell cycle by directly binding to Aurora B kinase in HeLa cells and retinoblastoma protein in hepatocytes (3). Moreover, Woo et al. demonstrated that Ssu72 bound to and reduced the phosphorylation of GM-CSF receptor (GM-CSFR) β-chain of alveolar macrophages, thereby providing fine-tuning of GM-CSFR signaling and being critical for the development and maturation of alveolar macrophages (4). These findings suggest that Ssu72 exerts RNA polymerase II–independent phosphatase activity in different cellular events, including immune cells. However, the function of Ssu72 in T cells has yet to be clearly reported.T cells make up a major subset of the adaptive immune system that plays critical roles in the regulation of autoimmunity, defense against pathogens, and tumor surveillance. To establish efficient T cell–mediated adaptive immune responses in vivo, the initiation and maintenance of appropriate T cell receptor (TCR)–mediated activation in T cells are mandatory (5, 6). Under steady-state conditions, ζ-chain–associated protein kinase 70 (ZAP-70) is bound to immunoreceptor tyrosine-based activation motifs (ITAMs) but is not phosphorylated, thus remaining in an auto-inhibited conformation during the response to self-peptides that are presented by a major histocompatibility complex class I or II molecule (5). In contrast, upon agonist peptide recognition, TCR complexes are clustered and lymphocyte-specific protein tyrosine kinase (Lck) phosphorylates tyrosine residues in the ITAMs of CD3 and ζ-chains. ZAP-70 is activated by binding to the phospho-tyrosine residues of the ζ-chains and by being phosphorylated itself (5, 6). In turn, activated ZAP-70 phosphorylates tyrosine residues on adaptor molecules such as linker for activation of T cells (LAT), thereby providing docking sites for cytosolic enzymes, including phospholipase C-γ1, and activating Ras and G proteins upstream of MAP kinases (5, 6). These findings indicate that ZAP-70 is an essential signaling molecule that regulates and propagates TCR signaling. In accordance, ZAP-70–deficient mice show an absolute defect in thymic development at the positive selection stage because of failure in TCR signaling (7).To ensure the appropriate stimulation of T cells, this signaling cascade of intracellular molecules is tightly regulated by a variety of mechanisms, thereby fine-tuning TCR signaling (5, 6). Thus, the regulation of the TCR signaling cascade contributes to the determination of TCR signaling strength, which affects the responses of T cells during development and activation. Aberrant mutations of ZAP-70 trigger an altered transduction of TCR signaling in T cells, resulting in dysregulation of thymic selection and autoimmune arthritis (8). Therefore, the fine-tuning of TCR signaling is critical for thymic development and the effector functions of T cells. For such fine-tuning, several mechanisms such as the progressive use of ITAM and modulation of signaling by coreceptors and inhibitory receptors have been suggested. The balancing of positive and negative regulation in critical signaling molecules, such as ZAP-70, also contributes to the fine-tuning of TCR signaling during T cell activation (5). However, less is known about the mechanism by which negative regulation of ZAP-70 determines TCR signaling strength than about that underlying positive regulation. ZAP-70 is dephosphorylated by several phosphatase, including phosphatase suppressor of TCR signaling (Sts)1, Sts2, low molecular weight phosphotyrosine phosphatase, and a vaccinia virus VH1-related, dual-specific protein phosphatase (5, 9–12). Ubiquitination and deubiquitination processes also regulate ZAP-70 activity by affecting interactions between ZAP-70 and phosphatases (13, 14). The ubiquitin E3 ligase Nrdp1 terminates CD8⁺ T cell activation via K33-linked polyubiquitination of ZAP-70, whereas Usp9X and Otud7b promote T cell activation by removing inhibitory ubiquitin from ZAP-70 (13–15). Moreover, Nrdp1 and Otud7b regulate the association of ZAP-70 and Sts1/Sts2 during T cell activation (15). Thus, ubiquitination/deubiquitination and phosphorylation/dephosphorylation systems cross-talk and play critical roles in the regulation of ZAP-70 activation balance in T cells. Nevertheless, the mechanism by which ZAP-70 is regulated via phosphorylation–dephosphorylation during T cell activation remains unclear.In this study, we found that the phosphatase Ssu72 was bound to ZAP-70 and inhibited its tyrosine phosphorylation via phosphatase activity. Moreover, Cd4-CreSsu72^fl/fl mice developed spontaneous inflammation via hyperactivation of T cells and the promotion of naïve T cell differentiation into effector and memory T cells.     

An experience on the model-based evaluation of pharmacokinetic drug-drug interaction for a long half-life drug

Fixed-dose combinations development requires pharmacokinetic drug-drug interaction (DDI) studies between active ingredients. For some drugs, pharmacokinetic properties such as long half-life or delayed distribution, make it difficult to conduct such clinical trials and to estimate the exact magnitude of DDI. In this study, the conventional (non-compartmental analysis and bioequivalence [BE]) and model-based analyses were compared for their performance to evaluate DDI using amlodipine as an example. Raw data without DDI or simulated data using pharmacokinetic models were compared to the data obtained after concomitant administration. Regardless of the methodology, all the results fell within the classical BE limit. It was shown that the model-based approach may be valid as the conventional approach and reduce the possibility of DDI overestimation. Several advantages (i.e., quantitative changes in parameters and precision of confidence interval) of the model-based approach were demonstrated, and possible application methods were proposed. Therefore, it is expected that the model-based analysis is appropriately utilized according to the situation and purpose.     

Clinical insights into hematologic malignancies and comparative analysis of molecular signatures of acute myeloid leukemia in different ethnicities using an artificial intelligence offering

Next generation sequencing generates copious amounts of genomics data, causing manual interpretation to be laborious and non-scalable while remaining subjective (even for highly trained specialists). We evaluated the performance of the artificial intelligence-based offering Watson for Genomics (WfG), a variant interpretation platform, in hematologic malignancies for the first time.Next generation sequencing was performed for patients treated for various hematological malignancies at Hallym University Sacred Heart Hospital, South Korea, between December 2017 and August 2020 using a 54-gene panel. Both WfG and expert manual curation were used to evaluate the performance of WfG. Acute myeloid leukemia (AML) molecular profiles were compared between Koreans and other ethnic groups using a publicly available dataset.Seventy-seven patients were analyzed (AML: 45, myeloproliferative neoplasms: 12, multiple myeloma: 7, myelodysplastic syndromes: 6, and others: 7). The concordance between the manual and WfG interpretations of 35 variants in 11 random patients was 94%. Among all patients, WfG identified 39 (51%) with at least 1 clinically actionable therapeutic alteration (i.e., a variant targeted by a United States Food and Drug Administration [US FDA]-approved drug, off-label drug, or clinical trial). Moreover, 46% of these patients (18/39) had genes that were targeted by a US FDA-approved therapy. WfG identified diagnostic or prognostic insights in 65% of the patients with no targetable alterations. In those with AML, FLT3-internal tandem duplications or tyrosine kinase domain mutations were less frequent among Koreans than among Caucasians (6.7% vs 30.2%, P < .001) or Hispanics (6.7% vs 28.3%, P = .005), suggesting ethnic differences.Variant interpretation using WfG correlated well with manually curated expert opinions. WfG provided therapeutic insights (including variant-specific drugs and clinical trials that cannot easily be provided by expert manual curation), as well as diagnostic and/or prognostic information.     

Regeneration of an electret filter by contact electrification

A facile and efficient method for the regeneration of electrostatic potential in electret filters by contact electrification (i.e., triboelectrification) was developed herein. The efficiency of a commercial polypropylene (PP) electret filter (PEF) for face masks was evaluated for filtration of particulate matter (PM) composed of fine solid dust and liquid droplets containing airborne bacteria (bioaerosol). The efficiency of pristine PEF for filtration of fine dust was 72.4%; however, this decreased to 62.7% following the removal of electrostatic charges in PEF by ethanol treatment. In contrast to fine dust, the bioaerosol (BA) removal efficiency of the filter was not affected by ethanol treatment because micro-sized liquid droplets could not penetrate the hydrophobic PEF surface. The electrostatic potential of PEF was restored or even enhanced by rubbing with Teflon, which exhibited a large triboelectric charge density. The PM removal efficiency of the resulting filter was higher than that of pristine PEF. Importantly, no performance degradation was observed even after 10 regenerations, demonstrating that the disposable filter can be reused to reduce the environmental problems associated with accumulation of waste.

Contact electrification restores the surface potential of a polypropylene electret filter for face masks and regenerates its filtration efficiency.     

Gongjin-Dan Enhances Neurite Outgrowth of Cortical Neuron by Ameliorating H2O2-Induced Oxidative Damage via Sirtuin1 Signaling Pathway

Gongjin-dan (GJD) is a multiherbal formula produced from 10 medicinal herbs and has been traditonally used as an oriental medicine to treat cardiovascular diseases, alcoholic hepatitis, mild dementia, and anemia. Additionally, increasing evidence suggests that GJD exerts neuroprotective effects by suppressing inflammation and oxidative stress-induced events to prevent neurological diseases. However, the mechanism by which GJD prevents oxidative stress-induced neuronal injury in a mature neuron remains unknown. Here, we examined the preventive effect and mechanism of GJD on primary cortical neurons exposed to hydrogen peroxide (H₂O₂). In the neuroprotection signaling pathway, Sirtuin1 is involved in neuroprotective action as a therapeutic target for neurological diseases. After pre-treatment with GJD at three concentrations (10, 25, and 50 µg/mL) and stimulation by H₂O₂ (30 µM) for 24 h, the influence of GJD on Sirtuin1 activation was assessed using immunocytochemistry, real-time PCR, western blotting, and flow cytometry. GJD effectively ameliorated H₂O₂-induced neuronal death against oxidative damage through Sirtuin1 activation. In addition, GJD-induced Sirtuin1 activation accelerated elongation of new axons and formation of synapses via increased expression of nerve growth factor and brain-derived neurotrophic factor, as well as regeneration-related genes. Thus, GJD shows potential for preventing neurological diseases via Sirtuin1 activation.     

Mesogen-jacketed liquid crystalline polymers via stable free radical polymerization

Stable free radical polymerization has been used in the controlled synthesis of poly(2,5-bis[(4-butylbenzoyl)oxy]styrene), PBBOS. This “mesogen-jacketed liquid crystalline polymer”, which has mesogenic units attached directly to the backbone in a side-on mode, has been found to exhibit thermotropic liquid crystallinity similar to more conventional main-chain architectures. Stable free radical polymerization of PBBOS consistently produced molecular weight distributions below the theoretical limiting polydispersity of 1.5 calculated for a conventional free radical polymerization process. Surprisingly, a comparison of the synthesis of polystyrene to the polymerization of PBBOS under nearly identical conditions showed that the PBBOS polymerized with a significantly higher reaction rate and monomer conversion efficiency. The nematic phase of these polymers was determined to be stable over the temperature range spanning the polymer glass transition temperature up to the temperature for thermal decomposition. The molecular arrangement of the PBBOS polymers was examined by wide-angle X-ray diffraction and is described here.     

Impact of the COVID-19 Pandemic on the Diagnosis and Surgery of Breast Cancer: A Multi-Institutional Study

PurposeThe coronavirus disease 2019 (COVID-19) pandemic has significantly impacted the rates of screening, case identification, and referral for cancer diagnosis. We investigated the diagnosis and surgery status of breast cancer before and after the COVID-19 pandemic at a multi-institutional level.MethodsWe collected breast cancer data from the clinical data warehouse which contained the medical records of patients from six academic institutions in South Korea. Patients were divided into two groups: February to April (period A) and May to July (period B). The data from the two groups were then compared against the same periods in 2019 and 2020. The primary objective was to investigate the differences in breast cancer stages before and after the COVID-19 pandemic.ResultsAmong 3,038 patients, there was a 9.9% reduction in the number of diagnoses in 2020. This decrease was more significant during period A than period B. The breast cancer stage was not statistically different in period A (p = 0.115), but it was in period B (p = 0.001). In the subset analysis according to age, there was a statistical difference between 2019 and 2020 in period B for patients under the age of 65 years (p = 0.002), but no difference was observed in the other groups.ConclusionThe number of breast cancer cases declined during the pandemic, and the staging distribution has changed after the pandemic peak.