Virological characteristics of the SARS-CoV-2 Omicron BA.2 spike.

Soon after the emergence and global spread of the SARS-CoV-2 Omicron lineage BA.1, another Omicron lineage, BA.2, began outcompeting BA.1. The results of statistical analysis showed that the effective reproduction number of BA.2 is 1.4-fold higher than that of BA.1. Neutralization experiments revealed that immunity induced by COVID vaccines widely administered to human populations is not effective against BA.2, similar to BA.1, and that the antigenicity of BA.2 is notably different from that of BA.1. Cell culture experiments showed that the BA.2 spike confers higher replication efficacy in human nasal epithelial cells and is more efficient in mediating syncytia formation than the BA.1 spike. Furthermore, infection experiments using hamsters indicated that the BA.2 spike-bearing virus is more pathogenic than the BA.1 spike-bearing virus. Altogether, the results of our multiscale investigations suggest that the risk of BA.2 to global health is potentially higher than that of BA.1.

Virological characteristics of the SARS-CoV-2 Omicron BA.2 subvariants, including BA.4 and BA.5.

After the global spread of the SARS-CoV-2 Omicron BA.2, some BA.2 subvariants, including BA.2.9.1, BA.2.11, BA.2.12.1, BA.4, and BA.5, emerged in multiple countries. Our statistical analysis showed that the effective reproduction numbers of these BA.2 subvariants are greater than that of the original BA.2. Neutralization experiments revealed that the immunity induced by BA.1/2 infections is less effective against BA.4/5. Cell culture experiments showed that BA.2.12.1 and BA.4/5 replicate more efficiently in human alveolar epithelial cells than BA.2, and particularly, BA.4/5 is more fusogenic than BA.2. We further provided the structure of the BA.4/5 spike receptor-binding domain that binds to human ACE2 and considered how the substitutions in the BA.4/5 spike play roles in ACE2 binding and immune evasion. Moreover, experiments using hamsters suggested that BA.4/5 is more pathogenic than BA.2. Our multiscale investigations suggest that the risk of BA.2 subvariants, particularly BA.4/5, to global health is greater than that of original BA.2.

Attenuated fusogenicity and pathogenicity of SARS-CoV-2 Omicron variant.

The emergence of the Omicron variant of SARS-CoV-2 is an urgent global health concern1. In this study, our statistical modelling suggests that Omicron has spread more rapidly than the Delta variant in several countries including South Africa. Cell culture experiments showed Omicron to be less fusogenic than Delta and than an ancestral strain of SARS-CoV-2. Although the spike (S) protein of Delta is efficiently cleaved into two subunits, which facilitates cell-cell fusion2,3, the Omicron S protein was less efficiently cleaved compared to the S proteins of Delta and ancestral SARS-CoV-2. Furthermore, in a hamster model, Omicron showed decreased lung infectivity and was less pathogenic compared to Delta and ancestral SARS-CoV-2. Our multiscale investigations reveal the virological characteristics of Omicron, including rapid growth in the human population, lower fusogenicity and attenuated pathogenicity.

Enhanced fusogenicity and pathogenicity of SARS-CoV-2 Delta P681R mutation.

During the current coronavirus disease 2019 (COVID-19) pandemic, a variety of mutations have accumulated in the viral genome of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and, at the time of writing, four variants of concern are considered to be potentially hazardous to human society1. The recently emerged B.1.617.2/Delta variant of concern is closely associated with the COVID-19 surge that occurred in India in the spring of 2021 (ref. 2). However, the virological properties of B.1.617.2/Delta remain unclear. Here we show that the B.1.617.2/Delta variant is highly fusogenic and notably more pathogenic than prototypic SARS-CoV-2 in infected hamsters. The P681R mutation in the spike protein, which is highly conserved in this lineage, facilitates cleavage of the spike protein and enhances viral fusogenicity. Moreover, we demonstrate that the P681R-bearing virus exhibits higher pathogenicity compared with its parental virus. Our data suggest that the P681R mutation is a hallmark of the virological phenotype of the B.1.617.2/Delta variant and is associated with enhanced pathogenicity.

Lusutrombopag Reduces the Risk of Hemoperitoneum Caused by Percutaneous Radiofrequency Ablation for Hepatocellular Carcinoma Compared with Platelet Transfusion.

INTRODUCTION: Patients with liver cirrhosis develop thrombocytopenia and an increased risk of bleeding events after invasive procedures. Lusutrombopag, a thrombopoietin receptor agonist, can increase the platelet count. This study assessed whether lusutrombopag reduces the risk of hemoperitoneum following percutaneous radiofrequency ablation for hepatocellular carcinoma, compared with platelet transfusion. METHODS: Participants in the present study comprised patients with severe thrombocytopenia (platelet count <50,000/µL) enrolled between November 2012 and March 2020, excluding patients with idiopathic thrombocytopenia or anticoagulant use. Hemoperitoneum rate, hemostasis rate, hemoglobin reduction rate, rate of achieving a platelet count ≥50,000/µL, and increases in platelet count and factors contributing to hemoperitoneum were retrospectively analyzed. RESULTS: This study enrolled 41 patients, comprising 18 patients administered lusutrombopag and 23 patients who received platelet transfusion. The major hemoperitoneum rate after RFA was tend to be lower in the lusutrombopag group (0%) than in the platelet transfusion group (21.7%). All of the major hemoperitoneum was observed in the platelet transfusion group. Hemoglobin reduction rate was lower in the lusutrombopag group (-0.17%) than in the platelet transfusion group (6.79%, p = 0.013). Hemostasis rate was lower in the lusutrombopag group (0%) than in the platelet transfusion group (21.7%, p = 0.045). The rate of achievement of platelet counts ≥50,000/µL the day after RFA was higher in the lusutrombopag group (100%) than in the platelet transfusion group (60.9%, p = 0.005). CONCLUSION: Lusutrombopag may be able to perform RFA more safely with respect to the hemoperitoneum caused by percutaneous radiofrequency ablation compared with platelet transfusion.

A Novel Hemostatic Peptide Solution for Common Acute Gastrointestinal Bleeding Diseases: First Case Series Study on the Treatment Results of Endoscopic Hemostasis by Nonexpert Endoscopists.

INTRODUCTION: We investigated the hemostatic effect and safety of a hemostatic peptide solution for the treatment of gastrointestinal bleeding requiring emergency endoscopy. METHODS: We retrospectively examined the patient backgrounds, hemostatic results, and procedural safety in patients who were treated with a hemostatic peptide solution for hemostasis during emergency endoscopies for gastrointestinal bleeding. All hemostatic procedures were performed by nonexpert physicians with less than 10 years of endoscopic experience. All of the cases were treated at a single institution over the months from January 2022 to January 2023. RESULTS: Twenty-six consecutive patients (17 males and 9 females) with a median age of 74 (45-95) years were included. Their conditions requiring emergency endoscopy were melena in 8 patients, hematochezia in 2, hematemesis in 8, anemia in 6, and bleeding during esophagogastroduodenoscopy in 2. The sites of bleeding were the esophagus in 3 patients, the stomach in 17, the duodenum in 3, the small intestine in 2, and the colon in 1. Hemostasis was obtained with another hemostasis device used in conjunction with the hemostatic peptide solution in 13 cases and with the hemostatic peptide solution alone in 13 cases. The hemostasis success rate was 100%, with no complications. Rebleeding occurred within 1 week in 4 cases. CONCLUSION: Hemostasis with the hemostatic peptide solution was safe and provided a temporary high hemostatic effect in emergency gastrointestinal endoscopy.

Scalable Synthesis of Planar Macroscopic Lipid-Based Multi-Compartment Structures.

As life evolved, the path from simple single cell organisms to multicellular enabled increasingly complex functionalities. The spatial separation of reactions at the micron scale achieved by cellular structures allowed diverse and scalable implementation in biomolecular systems. Mimicking such spatially separated domains in a scalable approach could open a route to creating synthetic cell-like structured systems. Here, we report a facile and scalable method to create multicellular-like, multi-compartment (MC) structures. Aqueous droplet-based compartments ranging from 50 to 400 µm were stabilized and connected together by hydrophobic layers composed of phospholipids and an emulsifier. Planar centimeter-scale MC structures were formed by droplet deposition on a water interface. Further, the resulting macroscopic shapes were shown to be achieved by spatially controlled deposition. To demonstrate configurability and potential versatility, MC assemblies of both homogeneous and mixed compartment types were shown. Notably, magnetically heterogeneous systems were achieved by the inclusion of magnetic nanoparticles in defined sections. Such structures demonstrated actuated motion with structurally imparted directionality. These novel and functionalized structures exemplify a route toward future applications including compartmentally assembled "multicellular" molecular robots.

Risk Factors for Infusion Reactions in Patients with Breast Cancer Administered Trastuzumab Therapy.

Trastuzumab is a humanized monoclonal antibody targeting human epidermal growth factor receptor 2 (HER2) that is indicated for the treatment of HER2-positive breast cancer. The administration of biologics, such as trastuzumab, frequently causes infusion reactions (IRs) with fever and chills. This study aimed to clarify the risk factors for IRs in trastuzumab therapy. Between March 2013 and July 2022, 227 patients with breast cancer who started trastuzumab therapy were included in this study. The severity of IRs was graded according to the Common Terminology Criteria for Adverse Events, Version 5.0. The incidence of IRs in trastuzumab therapy was 27.3% (62/227). Dexamethasone administration was significantly different between the IR and non-IR groups in patients receiving trastuzumab therapy (univariate analysis, p < 0.001; multivariate analysis, p = 0.0002). Without dexamethasone, the severity of IRs in the pertuzumab combination group (Grade 1, 8/65; Grade 2, 23/65) was significantly higher than that in the non-pertuzumab group (Grade 1, 9/37; Grade 2, 3/37; p < 0.05). Our findings suggest that the risk of IRs is significantly higher in patients not premedicated with dexamethasone in trastuzumab therapy and that the concomitant use of pertuzumab without dexamethasone increases the severity of IRs caused by trastuzumab.

Characterization of Biogenic PbS Quantum Dots.

Heavy metals in a polluted environment are toxic to life. However, some microorganisms can remove or immobilize heavy metals through biomineralization. These bacteria also form minerals with compositions similar to those of semiconductors. Here, this bioprocess was used to fabricate semiconductors with low energy consumption and cost. Bacteria that form lead sulfide (PbS) nanoparticles were screened, and the crystallinity and semiconductor properties of the resulting nanoparticles were characterized. Bacterial consortia that formed PbS nanoparticles were obtained. Extracellular particle size ranged from 3.9 to 5.5 nm, and lattice fringes were observed. The lattice fringes and electron diffraction spectra corresponded to crystalline PbS. The X-ray diffraction (XRD) patterns of bacterial PbS exhibited clear diffraction peaks. The experimental and theoretical data of the diffraction angles on each crystal plane of polycrystalline PbS were in good agreement. Synchrotron XRD measurements showed no crystalline impurity-derived peaks. Thus, bacterial biomineralization can form ultrafine crystalline PbS nanoparticles. Optical absorption and current-voltage measurements of PbS were obtained to characterize the semiconductor properties; the results showed semiconductor quantum dot behavior. Moreover, the current increased under light irradiation when PbS nanoparticles were used. These results suggest that biogenic PbS has band gaps and exhibits the general fundamental characteristics of a semiconductor.

[Primary mediastinal large B-cell lymphoma, spindle cell variant demonstrating atypical image findings].

The patient was a 40-year-old woman referred to our hospital after an anterior mediastinal tumor was detected. Imaging findings revealed a tumor with irregular margins and a marked tendency to infiltrate, with some calcification. Rather than malignant lymphoma, thymic carcinoma or high-grade invasive thymoma was suspected. Endobronchial ultrasound-guided transbronchial needle aspiration biopsy and computed tomography-guided needle biopsy were performed, but no diagnosis was made. Mediastinal tumor biopsy by video-assisted thoracic surgery led to the diagnosis of primary mediastinal large B-cell lymphoma, spindle cell variant. A retrospective examination of the needle biopsy specimens revealed that some tissues considered to have been crushed were composed of spindle-shaped lymphoma cells. This study indicates that it is crucial to note that there is a subtype of primary mediastinal large B-cell lymphoma with an unusual pathological morphology.

An older age, a longer duration between injury and surgery, and positive pivot shift test results increase the prevalence of articular cartilage injury during ACL reconstruction in all three compartments of the knee in patients with ACL injuries.

PURPOSE: To investigate factors that influence the prevalence of articular cartilage injury in patients with anterior cruciate ligament (ACL) injury. METHODS: This multicentre study included patients with ACL injury. Logistic regression analysis was conducted to identify factors that influence the prevalence of cartilage injury during ACL reconstruction. RESULTS: A total of 811 patients were enrolled. The factors that significantly influenced the prevalence of cartilage injury were age (odds ratio [OR], 1.04; P = 0.000), a positive pivot shift test result (OR, 1.43; P = 0.021), medial meniscal injury (OR, 2.55; P = 0.000), and delayed surgery (≥ 12 months) (OR, 2.52; P = 0.028) in the medial compartment of the knee; age (OR, 1.05; P = 0.000), subjective grades of apprehension during the pivot shift test (OR, 1.46; P = 0.010), lateral meniscal injury (OR, 1.98; P = 0.003), femoro-tibial angle (FTA) (OR, 0.92; P = 0.006), and delayed surgery (≥ 12 months) (OR, 2.63; P = 0.001) in the lateral compartment; and age (OR, 1.06; P = 0.000), body mass index (OR, 1.07; P = 0.028), a positive pivot shift test result (OR, 1.60; P = 0.018), FTA (OR, 0.90; P = 0.006), and delayed surgery (≥ 12 months) (OR, 3.17; P = 0.008) in the patellofemoral compartment. CONCLUSION: An older age, a longer duration between injury and surgery, and a positive pivot shift test result were positively associated with the prevalence of cartilage injury in three compartments in patients with ACL injuries. Early ACL reconstruction is recommended to prevent cartilage injury. LEVEL OF EVIDENCE: Level III.

[Primary leptomeningeal lymphoma with oculomotor paralysis as the initial presentation].

An 85-year-old man presented with right eye ptosis and visual abnormalities. Due to a lack of abnormal findings on plain magnetic resonance imaging (MRI) and laboratory examination, prednisolone therapy was initiated, and ocular myasthenia gravis and ocular symptoms subjectively improved. However, anorexia and conscious disorder appeared during the same period, and he was hospitalized for scrutiny. After admission, left eye adduction disorder and bilateral abduction nerve paralysis were also observed. Enhanced MRI revealed cranial nerve and leptomeninx enhancement. Subsequently, the patient developed seizures and died on the 10th day of hospitalization without being diagnosed. An autopsy revealed infiltration of B-cell lymphoma cells into the subarachnoid space, particularly in the parietal lobe. Similar infiltration was observed in the cerebellum, brainstem, spinal cord, and bilateral oculomotor nerve. Primary leptomeningeal lymphoma is a rare form of primary central nervous system lymphoma without simultaneous parenchymal brain lesions. Clinicians should be aware of this form of lymphoma and carefully monitor its possible occurrence, even when patients are already being treated for other neurological diseases.

Effect of Seleno-L-methionine on Oxidative Stress in the Pancreatic Islets of a Short-Term Induced Diabetic Mouse Model in Insufficient Selenium Status.

The protective effects of seleno-L-methionine (SeMet) on oxidative stress in pancreatic islets were investigated with a short-term nicotinamide (NA) and streptozotocin (STZ)-induced diabetic mouse model. ICR mice were intraperitoneally injected twice with 100 mg/kg STZ and 120 mg/kg NA at a 1-d interval and were then orally administered 158 µg Se/kg SeMet with free access to a selenium-deficient diet for 5 weeks. Administration of SeMet significantly improved the levels of glycated hemoglobin (HbA1c), non-fasting and oral glucose tolerance-tested (OGTT) blood glucose, plasma adiponectin and hepatic glycogen that deteriorated by NA/STZ treatment. However, supplementary SeMet did not restore non-fasting plasma insulin levels in NA/STZ treatment group and significantly suppressed OGTT plasma insulin levels in the control group. Although SeMet significantly suppressed 8-hydroxy-2'-deoxyguanosine density in pancreatic islets, SeMet did not restore insulin density. The hepatic and pancreatic mRNA levels of glutathione peroxidase 1 (GPX1) increased by NA/STZ treatment or SeMet administration. These results suggest that although a physiological level of SeMet improves glucose tolerance by exhibiting insulin-mimetic activity in a short-term induced diabetic mouse model under insufficient Se status, the suppression of pancreatic oxidative stress with the induction GPX1 by SeMet supplementation is unlikely to restore insulin storage and secretion.

Stepwise radical cation Diels-Alder reaction via multiple pathways.

Herein we disclose the radical cation Diels-Alder reaction of aryl vinyl ethers by electrocatalysis, which is triggered by an oxidative SET process. The reaction clearly proceeds in a stepwise fashion, which is a rare mechanism in this class. We also found that two distinctive pathways, including "direct" and "indirect", are possible to construct the Diels-Alder adduct.

Kupffer Imaging by Contrast-Enhanced Sonography With Perfluorobutane Microbubbles Is Associated With Outcomes After Radiofrequency Ablation of Hepatocellular Carcinoma.

OBJECTIVES: An ultrasound contrast agent consisting of perfluorobutane microbubbles (Sonazoid; Daiichi Sankyo, Tokyo, Japan) accumulates in Kupffer cells, which thus enables Kupffer imaging. This study aimed to elucidate the association of defect patterns of hepatocellular carcinoma during the Kupffer phase of Sonazoid contrast-enhanced sonography with outcomes after radiofrequency ablation (RFA). METHODS: For this study, 226 patients with initial hypervascular hepatocellular carcinoma, who could be evaluated by contrast-enhanced sonography with Sonazoid before RFA, were analyzed. Patients were divided into 2 groups according to the tumor defect pattern during the Kupffer phase. The irregular-defect group was defined as patients with hepatocellular carcinoma that had a defect with an irregular margin, and the no-irregular-defect group was defined as patients with hepatocellular carcinoma that had either a defect with a smooth margin or no defect. Critical recurrence was defined as more than 3 intrahepatic recurrences, vascular invasion, dissemination, or metastasis. RESULTS: The irregular-defect and no-irregular-defect groups included 86 and 140 patients, respectively, and had cumulative 5-year critical recurrence rates of 49% and 17% (P < .01). Multivariate analysis indicated that the tumor diameter, lens culinaris agglutinin- reactive α-fetoprotein level, and defect pattern were independent factors related to critical recurrence. The cumulative 5-year overall survival rates for the irregular-defect and no-irregular-defect groups were 46% and 61% (P< .01). Multivariate analysis indicated that the Child-Pugh class, tumor diameter, lens culinaris agglutinin-reactive α-fetoprotein level, and defect pattern were independent factors related to survival. CONCLUSIONS: The defect pattern of hepatocellular carcinoma during the Kupffer phase of Sonazoid contrast-enhanced sonography is associated with critical recurrence and survival after RFA.

Structural requirement and stereospecificity of tetrahydroquinolines as potent ecdysone agonists.

Tetrahydroquinoline (THQ)-type compounds are a class of potential larvicides against mosquitoes. The structure-activity relationships (SAR) of these compounds were previously investigated (Smith et al., Bioorg. Med. Chem. Lett. 2003, 13, 1943-1946), and one of cis-forms (with respect to the configurations of 2-methyl and 4-anilino substitutions on the THQ basic structure) was stereoselectively synthesized. However, the absolute configurations of C2 and C4 were not determined. In this study, four THQ-type compounds with cis configurations were synthesized, and two were submitted for X-ray crystal structure analysis. This analysis demonstrated that two enantiomers are packed into the crystal form. We synthesized the cis-form of the fluorinated THQ compound, according to the published method, and the enantiomers were separated via chiral HPLC. The absolute configurations of the enantiomers were determined by X-ray crystallography. Each of the enantiomers was tested for activity against mosquito larvae in vivo and competitive binding to the ecdysone receptor in vitro. Compared to the (2S,4R) enantiomer, the (2R,4S) enantiomer showed 55 times higher activity in the mosquito larvicidal assay, and 36 times higher activity in the competitive receptor binding assay.

Iodotyrosine deiodinase, a novel target of environmental halogenated chemicals for disruption of the thyroid hormone system in mammals.

Many synthetic chemicals have been identified as environmental contaminants with activity to disrupt normal function of the thyroid hormone system. Thyroid hormones play important roles in growth, development, differentiation, and basal metabolic homeostasis, as well as in brain development in human fetus and children, and thyroid dysfunction can have very serious consequences, including mental retardation. Environmental chemicals may affect thyroid hormone action in multiple ways, including reduced thyroid hormone synthesis owing to direct toxicity at the thyroid gland, interaction with thyroid hormone receptors and transporters such as transthyretin, and disturbance of thyroid hormone metabolism (e.g., glucuronidation, sulfation and deiodination). In addition, iodotyrosine deiodinase, which is involved in iodide salvage by catalyzing deiodination of iodinated by-products of thyroid hormone production, was recently identified as a possible new target for disruption of thyroid hormone homeostasis by environmental halogenated chemicals. This topic, after briefly summarizing findings on the thyroid hormone-disrupting action of environmental chemicals in mammals, focuses on the effects of environmental halogenated chemicals on iodotyrosine deiodinase activity.

Effects of administering sodium selenite, methylseleninic acid, and seleno-L-methionine on glucose tolerance in a streptozotocin/nicotinamide-induced diabetic mouse model.

The effects of administering the selenocompounds, sodium selenite, methylseleninic acid (MSA), and seleno-L-methionine (SeMet) on glucose tolerance were compared in the nicotinamide (NA) and streptozotocin (STZ)-induced diabetic mouse model. ICR mice were intraperitoneally treated twice with STZ (100 mg/kg) 15 min after an injection of NA (120 mg/kg) at a 1-d interval. Non-fasting blood glucose levels were then monitored weekly while orally administering the selenocompounds at 158 µg Se/kg body weight with free access to a selenium-deficient diet for 5 weeks. The mean body weights of NA/STZ-induced diabetic mice were partly restored by the administration of selenocompounds, while SeMet led to a higher selenium content and glutathione peroxidase 1 activity in the pancreas. Non-fasting and oral glucose tolerance-tested blood glucose levels, which were elevated by NA/STZ, were significantly suppressed by the administration of SeMet. These results suggest that SeMet may improve glucose tolerance in a NA/STZ-induced mild diabetic mouse model by increasing bioavailability in the pancreas.