Influence of COVID-19 pandemic on otitis media with effusion in children: A multicenter, retrospective survey in northern Japan.

OBJECTIVE: The purpose of this study is to compare patient trends in otitis media with effusion (OME) symptoms and diagnoses before and after the COVID-19 pandemic in order to investigate the effects of the coronavirus disease of 2019 (COVID-19). METHODS: A retrospective, multi-center, observational study was carried out between January 2018 and December 2022 at hospitals in the Iwate Prefecture with full-time doctors. All patients were initially separated into two groups, one for the pre-COVID-19 era (from January 2018 to June 2020), and the other for the COVID-19 era (from July 2020 to December 2022). RESULTS: In the pre-COVID-19 era, 132 patients had tympanostomy tubes (TT) placed, while 64 patients had them placed in the COVID-19 era. Between the pre-COVID-19 and COVID-19 eras, there were no statistically significant differences in terms of age, sex, side, craniofacial deformity, or adenoidectomy. Children in elementary school showed a greater decline than those in preschool (42-11 patients in elementary school (74%) and 49 to 32 patients in preschool school (35%); p = 0.025). CONCLUSIONS: The percentage of TT placements for OME dropped to roughly half during the COVID-19 epidemic. This was particularly obvious in elementary school students.

Salivary gland cancer organoids are valid for preclinical genotype-oriented medical precision trials.

Salivary gland cancers (SGCs) are heterogeneous tumors, and precision oncology represents a promising therapeutic approach; however, its impact on SGCs remains obscure. This study aimed to establish a translational model for testing molecular-targeted therapies by combining patient-derived organoids and genomic analyses of SGCs. We enrolled 29 patients, including 24 with SGCs and 5 with benign tumors. Resected tumors were subjected to organoid and monolayer cultures, as well as whole-exome sequencing. Organoid and monolayer cultures of SGCs were successfully established in 70.8% and 62.5% of cases, respectively. Organoids retained most histopathological and genetic profiles of their original tumors. In contrast, 40% of the monolayer-cultured cells did not harbor somatic mutations of their original tumors. The efficacy of molecular-targeted drugs tested on organoids depended on their oncogenic features. Organoids recapitulated the primary tumors and were useful for testing genotype-oriented molecular targeted therapy, which is valuable for precision medicine in patients with SGCs.

Development of a dye nanoparticle-loaded test strip for the Zn(II) determination in metal plating wastes.

Zincon/Latex-NR3+ nanocomposite-loaded dye nanoparticle coated test strip (Zincon/Latex-NR3+ DNTS) was fabricated to detect Zn(II) in plating wastewater by a unique color change from red-purple to deep blue and evaluated its detection performance in actual plating samples. The 5 × 5 mm square-cut DNTS attached sticks were immersed into 10 mL aliquots of aqueous solutions containing Zn(II) ion and 0.01 M TAPS buffer at pH 8.4 with stirring at 250 rpm for 60 min. The calibration curve for Zn(II) was prepared based on the integrated area intensity of reflectance by TLC at 620 nm with the 3σ detection limit was 48.61 ppb, and the quantitative range was approximately up to 1000 ppb. Although Cu(II), Mn(II), Ni(II), and Co(II) showed competitive interference due to complex formation with Zincon, a mixture of masking reagent including thiourea, 2-aminoethanthiol, and o-phenanthroline was effective in removing the contamination. To eliminate Cr(III) interference based on the incorporation of Zn(II) into Cr(III) hydrolyzed polymer, adding KBrO3 and H2SO4 under boiling for several minutes was required. With appropriate pretreatment, all results of actual plating water samples by Zincon/LatexNR3+ DNTS were close to those of ICP-OES.

Biosynthetic Gene Expression and Tissue Distribution of Diosgenin in Dioscorea japonica.

Diosgenin is an aglycone of dioscin, a major bioactive steroidal saponin found in plants, including Himalayan Paris (Paris polyphylla), fenugreek (Trigonella foenum-graecum), and yam (Dioscorea spp.). We have previously demonstrated that a species of natural yam, Dioscorea japonica, contains a promising bioactive compound diosgenin, which induces anti-carcinogenic and anti-hypertriacylglycerolemic activities. Here, we found for the first time that Japanese yam (D. japonica) bulbils are richer in diosgenin than the edible tubers (rhizomes) and leaves. LC-MS and imaging-MS analyses revealed that diosgenin accumulated in the peripheral region of D. japonica bulbils. Additionally, we performed RNA-seq analysis of D. japonica, and multiple sequence alignment identified D. japonica CYP90 (DjCYP90), the orthologous gene of CYP90G4 in P. polyphylla, CYP90B50 in T. foenum-graecum, CYP90G6 in Dioscorea zingiberensis, and CYP90G in Dioscorea villosa, which encodes a diosgenin biosynthetic rate-limiting enzyme. The expression levels of DjCYP90 were significantly upregulated in D. japonica bulbils than in its rhizomes and leaves. Since diosgenin is one of the most promising functional food factors executing several favorable bioactivities, D. japonica bulbils rich in diosgenin would be a beneficial natural resource.

Management of cholesterol granuloma due to eosinophilic otitis media using large ventilation tube.

A 46-year-old man who had been diagnosed with eosinophilic otitis media (EOM) and eosinophilic chronic rhinosinusitis was referred to our department. He suffered from bilateral earache, clogged ear sensation, and otorrhea associated with EOM. He had been treated with a myringotomy and a ventilation tube (VT) insertion. However, his symptoms did not improve, and the VT repeatedly fell out. We performed canal wall down mastoidectomy via a retro-auricular incision to remove the presumed cholesterol granuloma (CG) and a long-term VT insertion. The VT fell out repeatedly. Therefore, a large VT that Komune devised was inserted. Four months after reinsertion, there was no evidence of recurrent otorrhea or fallout of a large VT. A large VT insertion could be useful in the severe case of EOM with CG.

Bilateral Congenital Preauricular Fistula of the Cavum Conchae.

A 16-year-old female who had left auricular sinus infections was admitted to our hospital. On physical examination, bilateral sinus tract openings were noted at the cavum conchae. We used a surgical microscope to complete the total resection of the bilateral sinus at the cavum conchae. Also dissected was the cartilage from the cavum conchae. To our knowledge, surgical excision of cavum conchae sinuses has not been previously described.

Simple Endoscopic Method of Scoring Swallowing Function After Treatment in Advanced Head and Neck Cancer Patients.

The aim of this prospective, observational study was to evaluate the effectiveness of a simple endoscopic method for scoring swallowing function after treatment of advanced head and neck cancer patients. A prospective, observational study was conducted involving 60 patients who had undergone surgery or chemoradiation for advanced head and neck cancer. Endoscopic score of swallowing function, penetration aspiration scale (PAS) score measured by videofluorography, and functional oral intake scale (FOIS) score were recorded, and their correlations were examined. There was a positive correlation between endoscopic and PAS scores. Patients with endoscopic scores of 4 points or more had significantly higher PAS scores and lower FOIS scores than those with scores of 3 points or less. These positive correlations were found only in patients who underwent surgery, and not those who received chemoradiation. This study showed the effectiveness of the simple endoscopic method for scoring swallowing function in patients after surgery for advanced head and neck cancers.

Investigation of the diversity of human papillomavirus 16 variants and L1 antigenic regions relevant for the prevention of human papillomavirus-related oropharyngeal cancer in Japan.

OBJECTIVE: This study aimed to investigate the distribution of human papillomavirus 16 (HPV16) variants that contribute to the development of HPV-related oropharyngeal carcinoma (HPV-OPC) in the Japanese population and to evaluate genetic variations in the sequence encoding the L1 antigen region of the viral outer shell that is targeted by existing vaccines and is relevant for designing a prevention strategy to combat the exponential increase in HPV-OPC cases in Japan. METHODS: Seventy Japanese HPV-OPC patients treated at Tohoku University Hospital were included in the study. DNA was extracted from formalin-fixed, paraffin-embedded tissue samples. Polymerase chain reaction and direct nucleotide sequencing were performed to determine the nucleotide polymorphisms necessary for the classification of HPV16 variants and to assess genetic diversity in the HPV16 L1 antigen region, including the BC, DE, EF, FG, and HI loops. RESULTS: The most common variant of HPV16 was the A4 sublineage (88.6%), conventionally called the Asian type, followed by the A1/2/3 (10.0%) sublineage, classified as the European type. The only nonsynonymous substitution detected in the L1 antigen loop region was p.N181T in the EF loop, which was found in 28/70 (40%) cases. In contrast, no nonsynonymous substitutions were observed in the DE, FG, and HI loops, which are particularly important regions in the antigen loop targeted by existing HPV vaccines. CONCLUSION: The most common HPV16 variant in Japanese HPV-OPC patients was the A4 subtype. The L1 antigen region is highly conserved, suggesting sufficient efficacy of existing HPV vaccines. These findings provide important information that will aid in the design of an HPV16 infection control strategy using existing HPV vaccines to prevent the spread of HPV-OPC in Japan.

Asteltoxin inhibits extracellular vesicle production through AMPK/mTOR-mediated activation of lysosome function.

Cancer cells secrete aberrantly large amounts of extracellular vesicles (EVs) including exosomes, which originate from multivesicular bodies (MVBs). Because EVs potentially contribute to tumor progression, EV inhibitors are of interest as novel therapeutics. We screened a fungal natural product library. Using cancer cells engineered to secrete luciferase-labeled EVs, we identified asteltoxin, which inhibits mitochondrial ATP synthase, as an EV inhibitor. Low concentrations of asteltoxin inhibited EV secretion without inducing mitochondrial damage. Asteltoxin attenuated cellular ATP levels and induced AMPK-mediated mTORC1 inactivation. Consequently, MiT/TFE transcription factors are translocated into the nucleus, promoting transcription of lysosomal genes and lysosome activation. Electron microscopy analysis revealed that the number of lysosomes increased relative to that of MVBs and the level of EVs decreased after treatment with asteltoxin or rapamycin, an mTORC1 inhibitor. These findings suggest that asteltoxin represents a new type of EV inhibitor that controls MVB fate.

Discovery of two novel ALKBH5 selective inhibitors that exhibit uncompetitive or competitive type and suppress the growth activity of glioblastoma multiforme.

A group of RNA methylation enzymes is currently of interest as a new target for cancer therapy. Alpha-ketoglutarate-dependent dioxygenase B (AlkB) homolog 5 (ALKBH5) is an N6 -methyladenosine (m6 A) demethylation enzyme, and by high-throughput screening from pure small molecule compounds, we identified two novel inhibitors, Ena15 and Ena21, against it. Each compound showed either uncompetitive or competitive inhibition for 2-oxoglutarate (2OG). In addition, Ena21 had little inhibitory activity for fat mass and obesity-associated protein (FTO), which is another N6 -methyladenosine demethylation enzyme, while Ena15 enhanced the demethylase activity of FTO. The predicted binding poses of both compounds with the crystal structure of ALKBH5 (PDB ID: 4NRO) were comparable with these observations pertaining to the interaction of the 2OG catalytic site in this enzyme kinetics. Furthermore, either knockdown of ALKBH5 or inhibition with Ena15 or Ena21 inhibited cell proliferation of glioblastoma multiforme-derived cell lines, decreased cell population in the synthesis phase of the cell cycle, increased m6 A RNA level, and stabilized FOXM1 mRNA. Based on these results, Ena15 and Ena21 were found to be potential candidates that might help in further research into the biological function of ALKBH5.

MEK/ERK-mediated oncogenic signals promote secretion of extracellular vesicles by controlling lysosome function.

Cancer cells secrete large amounts of extracellular vesicles (EVs) originating from multivesicular bodies (MVBs). Mature MVBs fuse either with the plasma membrane for release as EVs, often referred as to exosomes or with lysosomes for degradation. However, the mechanisms regulating MVB fate remain unknown. Here, we investigated the regulators of MVB fate by analyzing the effects of signaling inhibitors on EV secretion from cancer cells engineered to secrete luciferase-labeled EVs. Inhibition of the oncogenic MEK/ERK pathway suppressed EV release and activated lysosome formation. MEK/ERK-mediated lysosomal inactivation impaired MVB degradation, resulting in increased EV secretion from cancer cells. Moreover, MEK/ERK inhibition prevented c-MYC expression and induced the nuclear translocation of MiT/TFE transcription factors, thereby promoting the activation of lysosome-related genes, including the gene encoding a subunit of vacuolar-type H+ -ATPase, which is responsible for lysosomal acidification and function. Furthermore, c-MYC upregulation was associated with lysosomal gene downregulation in MEK/ERK-activated renal cancer cells/tissues. These findings suggest that the MEK/ERK/c-MYC pathway controls MVB fate and promotes EV production in human cancers by inactivating lysosomal function.

Nivolumab-related myasthenia gravis with myositis requiring prolonged mechanical ventilation: a case report.

BACKGROUND: Nivolumab is an immune checkpoint inhibitor that blocks inhibitors of T-cell activation and blunts antitumor immunity and is used in the treatment of various cancers. However, immune checkpoint inhibitors have immune-related adverse effects on various organs due to promoting T-cell activity against host tissues by blocking inhibition of T-cell function. Although immune-related adverse effects including hepatitis, colitis, pneumonitis, dermatitis, nephritis, endocrinopathies, and hypophysitis are well recognized with established treatment guidelines, neuromuscular immune-related adverse effects are rare phenomena. CASE PRESENTATION: A 55-year-old Asian (Japanese) woman was diagnosed with nivolumab-related myasthenia gravis with myositis and myocarditis. She had a past history of thymectomy for large thymoma with a high anti-acetylcholine receptor antibody level without any symptoms. Nivolumab was administered for the treatment of malignant melanoma. Creatine kinase levels began to rise 2 weeks after the administration, and abnormal neurological findings appeared 3 weeks after the administration. Ventricular arrhythmia, wide QRS complex, and dyssynchrony of the left ventricle also appeared. Intravenous immunoglobulin and corticosteroids were administered, and plasma exchange was performed. The patient required intensive care and prolonged mechanical ventilation with tracheostomy owing to weakness of the diaphragm; she was eventually weaned from the ventilator and discharged. Diaphragm ultrasound was used for the decision-making of the weaning strategy and evaluation of the diaphragmatic function. CONCLUSIONS: Nivolumab-induced severe myasthenia gravis with myositis and myocarditis required intensive care and prolonged mechanical ventilation. Although immune checkpoint inhibitor-related myasthenia gravis is a rare adverse event, appropriate and prompt treatment is required because of its severity and rapid progression. Diaphragm ultrasound was useful not only in diagnosing diaphragm dysfunction and deciding the strategy for weaning from mechanical ventilation but also in evaluating the recovery of the diaphragmatic function.

Serum selenium predicts achievement of full-dose cisplatin in concurrent chemoradiotherapy for locally advanced head and neck squamous cell carcinoma: A prospective, observational study.

OBJECTIVE: Concurrent chemoradiotherapy (CCRT) with three-weekly high-dose cisplatin (100 mg/m2) is a standard treatment for locally advanced head and neck squamous cell carcinoma (HNSCC), but compliance with cisplatin is often poor due to various adverse events. The aim of this prospective, observational study was to determine the predictors of achievement of full-dose cisplatin. METHODS: A prospective, observational study was conducted involving 60 patients who received CCRT with three-weekly high-dose cisplatin (100 mg/m2) for locally advanced HNSCC. Possible predictors affecting compliance with cisplatin were subjected to univariate and multivariate logistic regression analyses. Age, sex, primary site, clinical stage, treatment intent, history of hypertension, diabetes mellitus, smoking and drinking habits, body mass index, creatinine clearance, serum albumin, controlling nutrition status, trace elements (Fe, Zn, Cu, Se), acute kidney injury, white blood cell count decrease, neutrophilia, and weight loss were the variables evaluated. RESULTS: Twenty-seven patients achieved full-dose cisplatin (300 mg/m2), and the other 33 patients did not. Multivariate logistic regression analysis showed that both mild renal dysfunction and selenium deficiency before treatment independently had negative impacts on achievement of full-dose cisplatin. CONCLUSIONS: As well as renal function, selenium deficiency is a potential therapeutic target for CCRT with high-dose cisplatin in HNSCC patients.

Whole exome sequencing and establishment of an organoid culture of the carcinoma showing thymus-like differentiation (CASTLE) of the parotid gland.

Carcinoma showing thymus-like differentiation (CASTLE) is a rare tumor, especially in the parotid gland. We encountered a CASTLE of the parotid gland and analyzed its clinicopathological features, as well as the genotype using whole exome sequencing (WES). Moreover, we successfully established an organoid culture cell line from the primary tumor tissue. The patient was a 23-year-old woman who underwent superficial parotidectomy with peripheral neck dissection, followed by radiotherapy. Pathologically, the resected specimen showed atypical epithelioid nests and trabeculae with squamous differentiation, separated by thick fibrous septa, accompanied by dense lymphocytes and plasma cell infiltration. Immunohistochemistry revealed that the tumor cells were positive for AE1/AE3, p40, p63, p16, CK5/6, and CD5, and the background lymphocytes were positive for CD5 and CD99. Based on these findings, the tumor was diagnosed as CASTLE. WES uncovered five nonsynonymous and splicing somatic mutations, namely, FREM2 p.Val861Phe, CLK3 p.Phe376Leu, DLGAP1 p.Lys294Asn, NOX1 p.Val165Met, and PSG9 c.430 + 4A > T. Organoid culture cells preserved the histopathological characteristics of the epithelioid component of CASTLE and harbored all five somatic mutations detected in the primary tumor. In conclusion, for the first time to the best of our knowledge, we successfully analyzed a comprehensive genotype and established an organoid culture cell line of a parotid gland CASTLE, which should serve for analyzing the nature of this rare tumor.

Role of Raf-like kinases in SnRK2 activation and osmotic stress response in plants.

Environmental drought and high salinity impose osmotic stress, which inhibits plant growth and yield. Thus, understanding how plants respond to osmotic stress is critical to improve crop productivity. Plants have multiple signalling pathways in response to osmotic stress in which the phytohormone abscisic acid (ABA) plays important roles. However, since little is known concerning key early components, the global osmotic stress-signalling network remains to be elucidated. Here, we review recent advances in the identification of osmotic-stress activated Raf-like protein kinases as regulators of ABA-dependent and -independent signalling pathways and discuss the plant stress-responsive kinase network from an evolutionary perspective.

Clinical utility of apparent diffusion coefficient and diffusion-weighted magnetic resonance imaging for resectability assessment of head and neck tumors with skull base invasion.

BACKGROUND: The usefulness of apparent diffusion coefficient (ADC) and diffusion-weighted magnetic resonance imaging (DWI) in the detection of malignant tumors has been reported. The purpose of this study is to clarify the role of ADC and DWI for diagnosis of skull base tumors. METHODS: A total of 27 patients with head and neck tumors with skull base invasions undergoing skull base surgery were enrolled in this study. Pathological findings of dural invasion and bone invasion were compared with the diagnostic imaging. RESULTS: Advanced magnetic resonance imaging techniques revealed that ADC values in regions of pathological bone and dural invasions were significantly lower than in regions of no invasion. The area under the curve of ADC in bone invasions and dural invasions were 0.957 and 0.894, respectively. CONCLUSIONS: Our findings indicate that ADC and DWI are useful tools for the diagnosis of head and neck tumors with skull base invasion.

Efficacy of relaxin for cisplatin-induced testicular dysfunction and epididymal spermatotoxicity.

BACKGROUND: Cisplatin (CP) is an extremely effective anticancer agent widely used to treat various cancer types, however, the potential side effects include testicular dysfunction. This study was to investigate, using a rat model of CP-induced testicular dysfunction, the protective effects of relaxin (RLN) against oxidative stress, testicular function, histological damage, spermatogenesis, germ-cell apoptosis, and sperm output, and to explore the usefulness of RLN as a potential protective drug for use with CP in chemotherapeutic treatments. METHODS: Sprague-Dawley male rats were used, which were divided into three groups: sham control, CP, and CP + RLN. Porcine RLN (500 ng/h) or saline was infused for 5 days using an implanted osmotic mini-pump following intraperitoneal injection of CP (6 mg/kg). RLN dose was chosen based on previous studies showing that it resulted in serum relaxin levels comparable to those in rats at the middle of pregnancy. At 5 days after CP administration, samples were collected and assessment of testicular histopathology, germ-cell apoptosis, oxidative stress, lipid peroxidation, and sperm quality was performed as main measures. RESULTS: The testicular CP model showed reduced testis weight and significantly decreased spermatogenesis scores. Additionally, CP administration induced a 4.6-fold increase in the apoptotic index associated with a significant increase in oxidative stress and upregulation of pro-apoptotic Casp3 and downregulation of anti-apoptotic Bcl2 levels, resulting in a marked reduction in sperm concentration. However, RLN administration caused a significant reduction in CP-mediated damage by attenuating oxidative stress and cell apoptosis. RLN administration efficiently scavenged ROS via the activation of SOD, CAT, and GPx and upregulation of GSH to prevent lipid peroxidation and decreased apoptosis by altering Bcl2 and Casp3 expression, thereby reducing histopathological damage and restoring spermatogenesis. Furthermore, RLN ameliorated attenuated sperm motility in the cauda epididymis resulting from CP treatment. CONCLUSIONS: This study clearly indicates that RLN exerts a protective effect against CP-induced testicular damage through attenuation of oxidative stress and suppression of apoptosis. Our findings suggest RLN as a potentially efficacious drug for use with cisplatin chemotherapy in order to ameliorate CP-induced side effects and testicular injury adversely affecting spermatogenesis, sperm quality, and oxidative-stress parameters.

CONTEXTE: Le cis platine (CP) est un agent anticancéreux extrêmement efficace largement utilisé pour traiter divers types de cancer. Parmi les effets secondaires potentiels associés aux traitements par CP on compte le dysfonctionnement des testicules. Le propos de ce manuscrit est d'étudier, à l'aide d'un modèle rat de dysfonctionnement testiculaire induit par la prise de CP, l'action protectrice de la relaxine (RLN) contre les effets délétères dus au CP lesquels incluent le stress oxydant, la perte de fonction testiculaire, les dommages histologiques au testicule, l'apoptose des cellules germinales et la baisse de la qualité des spermatozoïdes. L'objectif est d'explorer l'utilité de la RLN comme médicament protecteur potentiel à utiliser avec le CP dans les traitements chimiothérapeutiques. MÉTHODES: Des rats mâles Sprague-Dawley ont été utilisés. Trois groupes : contrôle, CP, et CP + RLN ont été comparés. Après une injection intrapéritonéale de CP (6mg/kg), de la RLN porcine (500 ng/h) ou du sérum physiologique a été perfusé pendant 5 jours en utilisant une mini-pompe osmotique implantée. La dose de RLN a été choisie en fonction d'études antérieures qui avaient montré qu'elle entraînait des taux sériques de RLN comparables à ceux de rats en milieu de la gestation. Cinq jours après l'administration de la CP, des échantillons ont été prélevés afin d'évaluer l'histopathologie, l'apoptose des cellules germinales, le stress oxydant, la peroxydation des lipides et les paramètres spermatiques. RÉSULTATS: Le groupe CP a montré une réduction du poids des testicules et une diminution significative des scores de spermatogenèse. De plus, l'administration de CP a entraîné une augmentation de l'apoptose de 4,6 fois associée à une augmentation significative du stress oxydant, de la régulation à la hausse de la Caspase 3 pro-apoptotique et à la baisse de Bcl2 anti-apoptotique conduisant in fine à une réduction marquée de la concentration en spermatozoïdes. La RLN a ainsi significativement corrigée les effets négatifs du CP en atténuant le stress oxydant et l'apoptose. La RLN a permis d'éliminer efficacement les ROS via l'activation de la triade enzymatique anti-oxydante superoxyde dismutase (SOD)/catalase (CAT)/glutathion peroxydase (GPx) et via la régulation à la hausse du GSH prévenant ainsi la lipopéroxydation. La RLN a par ailleurs diminué les atteintes histopathologiques testiculaires préservant la spermatogenèse. En parallèle, la RLN a amélioré la mobilité spermatique des spermatozoïdes prélevés dans la queue de l'épididyme. CONCLUSIONS: Cette étude montre clairement que la RLN exerce un effet protecteur contre les lésions testiculaires par l'atténuation du stress oxydant et la suppression de l'apoptose induite par le CP. Nos résultats suggèrent que la RLN est un médicament potentiellement pertinent à utiliser afin de diminuer les effets secondaires induits par le CP sur la fonction testiculaire et sur les spermatozoïdes lors de la chimiothérapie cancéreuse.

Regeneration of esophagus using a scaffold-free biomimetic structure created with bio-three-dimensional printing.

Various strategies have been attempted to replace esophageal defects with natural or artificial substitutes using tissue engineering. However, these methods have not yet reached clinical application because of the high risks related to their immunogenicity or insufficient biocompatibility. In this study, we developed a scaffold-free structure with a mixture of cell types using bio-three-dimensional (3D) printing technology and assessed its characteristics in vitro and in vivo after transplantation into rats. Normal human dermal fibroblasts, human esophageal smooth muscle cells, human bone marrow-derived mesenchymal stem cells, and human umbilical vein endothelial cells were purchased and used as a cell source. After the preparation of multicellular spheroids, esophageal-like tube structures were prepared by bio-3D printing. The structures were matured in a bioreactor and transplanted into 10-12-week-old F344 male rats as esophageal grafts under general anesthesia. Mechanical and histochemical assessment of the structures were performed. Among 4 types of structures evaluated, those with the larger proportion of mesenchymal stem cells tended to show greater strength and expansion on mechanical testing and highly expressed α-smooth muscle actin and vascular endothelial growth factor on immunohistochemistry. Therefore, the structure with the larger proportion of mesenchymal stem cells was selected for transplantation. The scaffold-free structures had sufficient strength for transplantation between the esophagus and stomach using silicon stents. The structures were maintained in vivo for 30 days after transplantation. Smooth muscle cells were maintained, and flat epithelium extended and covered the inner surface of the lumen. Food had also passed through the structure. These results suggested that the esophagus-like scaffold-free tubular structures created using bio-3D printing could hold promise as a substitute for the repair of esophageal defects.

N-terminal HCV core protein fragment decreases 20S proteasome activity in the presence of PA28γ.

The Hepatitis C virus (HCV) core protein plays a crucial role in the development of chronic liver diseases such as chronic hepatitis, cirrhosis, and hepatocellular carcinoma (HCC). Its involvement in these diseases is reportedly abolished by a knockout of the proteasome activator PA28γ gene in transgenic mice, suggesting an interaction between the core protein and the PA28γ-proteasome system. This study found a direct interaction between the N-terminal 1-71 fragment of HCV core protein (Core71) and PA28γ in vitro, and that this interaction was found to enhance PA28γ-20S proteasome complex formation. While 20S proteasome activity was increased by PA28γ, it was significantly reduced by Core71 attachment in a dose-dependent manner. These results suggest that the Core-PA28γ interaction has an important role in regulating 20S proteasome activity and furthers our understanding of the pathogenesis of HCV.