Significance and Amplification Methods of the Purine Salvage Pathway in Human Brain Cells.

Previous studies suggest that uric acid or reactive oxygen species, products of xanthine oxidoreductase (XOR), may associate with neurodegenerative diseases. However, neither relationship has ever been firmly established. Here, we analyzed human brain samples, obtained under protocols approved by research ethics committees, and found no expression of XOR and only low levels of uric acid in various regions of the brain. In the absence of XOR, hypoxanthine will be preserved and available for incorporation into the purine salvage pathway. To clarify the importance of salvage in the brain, we tested using human induced pluripotent stem cell-derived neuronal cells. Stable isotope analyses showed that the purine salvage pathway was more effective for ATP synthesis than purine de novo synthesis. Blood uric acid levels were related to the intracellular adenylate pool (ATP + ADP + AMP), and reduced levels of this pool result in lower uric acid levels. XOR inhibitors are related to extracellular hypoxanthine levels available for uptake into the purine salvage pathway by inhibiting the oxidation of hypoxanthine to xanthine and uric acid in various organs where XOR is present and can prevent further decreases in the intracellular adenylate pool under stress. Furthermore, adding precursors of the pentose phosphate pathway enhanced hypoxanthine uptake, indicating that purine salvage is activated by PRPP replenishment. These findings resolve previous contradictions regarding XOR products and provide new insights into clinical studies. It is suggested that therapeutic strategies maximizing maintenance of intracellular adenylate levels may effectively treat pathological conditions associated with ischemia and energy depletion.

Characteristics and clinical outcomes of patients with combined burns and trauma in Japan: Analysis of a nationwide trauma registry database.

INTRODUCTION: Patients with combined burns and trauma are often seen in the United States. The combination of trauma with burns increases mortality. In contrast, the characteristics and outcomes of these cases remain unknown in Japan. This study investigated the characteristics and outcomes of trauma associated with burns in Japan. METHODS: This multicenter retrospective cohort study was conducted by utilizing data from the Japan Trauma Data Bank for the period between 2004 and 2017. We evaluated the characteristics of burn patients (n = 5783) divided into two groups: burns only (n = 5537) and combined burns and trauma (n = 246). Clinical characteristics, including patient background, severity of trauma, injury mechanism, total body surface area affected, injury location, treatments, and clinical outcomes, were examined. RESULTS: Most patients in both the groups were injured by flames. The number proportion of patients with 40-89% of the total body surface area affected was 1069/5537 (19.3%) in the burn-only group and 23/246 (9.3%) in the combined burn and trauma group. The in-hospital mortality was 1006/5537 (18.2%) in the burn-only group and 17/246 (6.9%) in the combined burn and trauma group. CONCLUSIONS: We demonstrated the characteristics of Japanese patients with burns only compared with those with combined burns and trauma. Flames were the main cause of burns, and in-hospital mortality was lower in the combined burn and trauma group associated with a smaller burn area.

The components of the AhR-molecular chaperone complex differ depending on whether the ligands are toxic or non-toxic.

The aryl hydrocarbon receptor (AhR) forms a complex with the HSP90-XAP2-p23 molecular chaperone when the cells are exposed to toxic compounds. Recently, 1,4-dihydroxy-2-naphthoic acid (DHNA) was reported to be an AhR ligand. Here, we investigated the components of the molecular chaperone complex when DHNA binds to AhR. Proteins eluted from the 3-Methylcolanthrene-affinity column were AhR-HSP90-XAP2-p23 complex. The AhR-molecular chaperone complex did not contain p23 in the eluents from the DHNA-affinity column. In 3-MC-treated cells, AhR formed a complex with HSP90-XAP2-p23 and nuclear translocation occurred within 30 min, while in DHNA-treated cells, AhR formed a complex with AhR-HSP90-XAP2, and translocation was slow from 60 min. Thus, the AhR activation mechanism may differ when DHNA is the ligand compared to toxic ligands.

Refolding, Crystallization, and Crystal Structure Analysis of a Scavenger Receptor Cysteine-Rich Domain of Human Salivary Agglutinin Expressed in Escherichia coli.

Scavenger receptors are a protein superfamily that typically consists of one or more repeats of the scavenger receptor cysteine-rich structural domain (SRCRD), which is an ancient and highly conserved protein module. The expression and purification of eukaryotic proteins containing multiple disulfide bonds has always been challenging. The expression systems that are commonly used to express SRCRD proteins mainly consist of eukaryotic protein expression systems. Herein, we established a high-level expression strategy of a Type B SRCRD unit from human salivary agglutinin using the Escherichia coli expression system, followed by a refolding and purification process. The untagged recombinant SRCRD was expressed in E. coli using the pET-32a vector, which was followed by a refolding process using the GSH/GSSG redox system. The SRCRD expressed in E. coli SHuffle T7 showed better solubility after refolding than that expressed in E. coli BL21(DE3), suggesting the importance of the disulfide bond content prior to refolding. The quality of the refolded protein was finally assessed using crystallization and crystal structure analysis. As proteins refolded from inclusion bodies exhibit a high crystal quality and reproducibility, this method is considered a reliable strategy for SRCRD protein expression and purification. To further confirm the structural integrity of the refolded SRCRD protein, the purified protein was subjected to crystallization using sitting-drop vapor diffusion method. The obtained crystals of SRCRD diffracted X-rays to a resolution of 1.47 Å. The solved crystal structure appeared to be highly conserved, with four disulfide bonds appropriately formed. The surface charge distribution of homologous SRCRD proteins indicates that the negatively charged region at the surface is associated with their calcium-dependent ligand recognition. These results suggest that a high-quality SRCRD protein expressed by E. coli SHuffle T7 can be successfully folded and purified, providing new options for the expression of members of the scavenger receptor superfamily.

"KAIZEN" method realizing implementation of deep-learning models for COVID-19 CT diagnosis in real world hospitals.

Numerous COVID-19 diagnostic imaging Artificial Intelligence (AI) studies exist. However, none of their models were of potential clinical use, primarily owing to methodological defects and the lack of implementation considerations for inference. In this study, all development processes of the deep-learning models are performed based on strict criteria of the "KAIZEN checklist", which is proposed based on previous AI development guidelines to overcome the deficiencies mentioned above. We develop and evaluate two binary-classification deep-learning models to triage COVID-19: a slice model examining a Computed Tomography (CT) slice to find COVID-19 lesions; a series model examining a series of CT images to find an infected patient. We collected 2,400,200 CT slices from twelve emergency centers in Japan. Area Under Curve (AUC) and accuracy were calculated for classification performance. The inference time of the system that includes these two models were measured. For validation data, the slice and series models recognized COVID-19 with AUCs and accuracies of 0.989 and 0.982, 95.9% and 93.0% respectively. For test data, the models' AUCs and accuracies were 0.958 and 0.953, 90.0% and 91.4% respectively. The average inference time per case was 2.83 s. Our deep-learning system realizes accuracy and inference speed high enough for practical use. The systems have already been implemented in four hospitals and eight are under progression. We released an application software and implementation code for free in a highly usable state to allow its use in Japan and globally.

Evaluation of the therapeutic efficiency and efficacy of blood purification in the treatment of severe acute pancreatitis.

This study aimed to evaluate the therapeutic efficacy and effect of blood purification (BP) therapy on severe acute pancreatitis (SAP). Information on 305 patients (BP group 68, control group 237) diagnosed with SAP was retrieved from the Medical Information Mart for Intensive Care IV (MIMIC IV) database. Firstly, the influence of BP treatment was preliminarily evaluated by comparing the outcome indicators of the two groups. Secondly, multiple regression analysis was used to screen the mortality risk factors to verify the impact of BP on the survival outcome of patients. Then, the effect of BP treatment was re-validated with baseline data. Finally, cox regression was used to make the survival curve after matching to confirm whether BP could affect the death outcome. The results indicated that the BP group had a lower incidence of shock (p = 0.012), but a higher incidence of acute kidney injury (AKI) (p < 0.001), with no differences observed in other outcome indicators when compared to the control group. It was also found that the 28-day survival curve of patients between the two groups was significantly overlapped (p = 0.133), indicating that BP treatment had no significant effect on the survival outcome of patients with SAP. Although BP is beneficial in stabilizing hemodynamics, it has no effect on short- and long-term mortality of patients. The application of this technology in the treatment of SAP should be done with caution until appropriate BP treatment methods are developed, particularly for patients who are not able to adapt to renal replacement therapy.

Molecular mechanism of Fe3+ binding inhibition to Vibrio metschnikovii ferric ion-binding protein, FbpA, by rosmarinic acid and its hydrolysate, danshensu.

Global warming has increased the growth of pathogenic Vibrio bacteria, which can cause foodborne illnesses and death. Vibrio bacteria require iron for growth and survival. They utilize a ferric ion-binding protein (FbpA) to bind and transport Fe3+ into the cell. FbpA from Vibrio metschnikovii (Vm) is a potential target for inhibiting its growth. Rosmarinic acid (RA) can block the binding of VmFbpA to Fe3+ ; however, the molecular mechanism of Fe3+ binding and RA inhibition to VmFbpA is unclear. In this study, we used x-ray crystallography to determine the Fe3+ -binding mode of VmFbpA and the mechanism of RA inhibition. The structures revealed that in the Fe3+ bound form, Fe3+ was coordinated to VmFbpA by two Tyr residues, two HCO3 - ions, and two water molecules in a six-coordinated geometry. In contrast, in the inhibitor bound form, RA was initially bound to VmFbpA following gel filtration purification, but it was hydrolyzed to danshensu (DSS), which occupied the binding site as shown in an electron density map and reverse phase chromatography (RPC) analysis. Both RA and DSS exhibited a stronger binding affinity to VmFbpA, higher Fe3+ reduction capacity, and more potent bacteriostatic effect on V. metschnikovii compared with caffeic acid (CA), another hydrolysis product of RA. These results provide insight into the mechanism of iron acquisition by V. metschnikovii and inhibition by RA and DSS. Our findings offer clues on the development of effective strategies to prevent Vibrio infections.

Therapeutic interventions and the length of hospital stay for pediatric patients with COVID-19: a multicenter cohort study.

The evidence for pediatric patients with COVID-19 was very limited, which was attributed to the small number of the cases as well as the rare incidence of severe pneumonia in this population. This retrospective cohort study aimed to identify the characteristics of pediatric patients with COVID-19 in the early period of the pandemic by analyzing Diagnosis Procedure Combination (DPC) data in Japan. This retrospective cohort analysis of Japanese multicenter research on COVID-19 using DPC data compared the outcomes and costs of treatment for pediatric patients with COVID-19. Of 4700 patients with COVID-19, 186 pediatric patients were included in this study. Among the included pediatric patients, 17 received therapeutic drugs specifically for COVID-19, while the remaining 169 pediatric patients received only symptomatic therapy. There were no significant differences in the length of hospital stay (9 vs. 8 days, p = 0.96), and medical cost (97,585 vs. 73,291 JPY) for the intervention and control groups, respectively by multiple regression analysis. This is the first epidemiological study to use DPC data to summarize the pathophysiology of pediatric patients in the early period of COVID-19 pandemic. There was no significant difference in length of hospital stay or medical cost by intervention.

Comparative genomic and transcriptomic analyses of African swine fever virus strains.

African swine fever (ASF) is the most devastating disease caused by the African swine fever virus (ASFV), impacting the pig industry worldwide and threatening food security and biodiversity. Although two vaccines have been approved in Vietnam to combat ASFV, the complexity of the virus, with its numerous open reading frames (ORFs), necessitates a more diverse vaccine strategy. Therefore, we focused on identifying and investigating the potential vaccine targets for developing a broad-spectrum defense against the virus. This study collected the genomic and/or transcriptomic data of different ASFV strains, specifically from in vitro studies, focusing on comparisons between genotypes I, II, and X, from the National Center for Biotechnology Information (NCBI) database. The comprehensive analysis of the genomic and transcriptomic differences between high- and low-virulence strains revealed six early genes, 13 late genes, and six short genes as potentially essential ORFs associated with high-virulence. In addition, many other ORFs (e.g., 14 multigene family members) are worth investigating. The results of this study provided candidate ORFs for developing ASF vaccines and therapies.

Allopurinol and oxypurinol differ in their strength and mechanisms of inhibition of xanthine oxidoreductase.

Xanthine oxidoreductase is a metalloenzyme that catalyzes the final steps in purine metabolism by converting hypoxanthine to xanthine and then uric acid. Allopurinol, an analog of hypoxanthine, is widely used as an antigout drug, as xanthine oxidoreductase-mediated metabolism of allopurinol to oxypurinol leads to oxypurinol rotation in the enzyme active site and reduction of the molybdenum Mo(VI) active center to Mo(IV), inhibiting subsequent urate production. However, when oxypurinol is administered directly to a mouse model of hyperuricemia, it yields a weaker urate-lowering effect than allopurinol. To better understand its mechanism of inhibition and inform patient dosing strategies, we performed kinetic and structural analyses of the inhibitory activity of oxypurinol. Our results demonstrated that oxypurinol was less effective than allopurinol both in vivo and in vitro. We show that upon reoxidation to Mo(VI), oxypurinol binding is greatly weakened, and reduction by xanthine, hypoxanthine, or allopurinol is required for reformation of the inhibitor-enzyme complex. In addition, we show oxypurinol only weakly inhibits the conversion of hypoxanthine to xanthine and is therefore unlikely to affect the feedback inhibition of de novo purine synthesis. Furthermore, we observed weak allosteric inhibition of purine nucleoside phosphorylase by oxypurinol which has potentially adverse effects for patients. Considering these results, we propose the single-dose method currently used to treat hyperuricemia can result in unnecessarily high levels of allopurinol. While the short half-life of allopurinol in blood suggests that oxypurinol is responsible for enzyme inhibition, we anticipate multiple, smaller doses of allopurinol would reduce the total allopurinol patient load.

A Case of Tracheoesophageal Fistula in a Non-metastatic Site During Lenvatinib Treatment for Hepatocellular Carcinoma.

BACKGROUND/AIM: We report a case of tracheo-esophageal fistula at a non-metastatic site during lenvatinib treatment of hepatocellular carcinoma with multiple bone metastases. CASE REPORT: A 58-year-old male patient was diagnosed with hepatocellular carcinoma with multiple bone metastases and was treated with atezolizumab-bevacizumab. However, as the bone metastasis progressed, palliative radiation therapy was administered to the third thoracic vertebra, and lenvatinib was administered as a second-line treatment. The patient was hospitalized for aspiration pneumonia five months later. Chest computed tomography and bronchoscopy revealed a 5 cm tracheoesophageal fistula located 3 cm cranial to the carina. We diagnosed a benign tracheoesophageal fistula due to lenvatinib because his previous CT scan showed no metastases at the site of the fistula, and we performed esophageal bypass surgery 4 weeks after discontinuation of the lenvatinib. CONCLUSION: To the best of our knowledge, this is the first case report of tracheoesophageal fistula at a nonmetastatic site during lenvatinib treatment for hepatocellular carcinoma.

Use of preoperative contrast-enhanced computed tomography in damage control strategy for blunt liver injury: A case report.

For patients with unstable abdominal trauma unresponsive to initial transfusion, the damage control strategy includes prompt hemostasis by open surgery and packing. Recently, a hybrid treatment that combines packing and transcatheter arterial embolization as a damage control strategy was reported to be effective; however, the indications and techniques are yet to be established. A 25-year-old male patient who was in shock due to severe liver injury after a traffic accident was brought to our emergency room by emergency services. After initial resuscitation, including resuscitative endovascular balloon occlusion of the aorta and blood transfusion, preoperative contrast-enhanced computed tomography indicated grade IV liver injury with active bleeding from the right hepatic artery. Damage control strategy with packing and subsequent transcatheter arterial embolization was determined to be useful. During treatment, bile leakage was observed. An endoscopic nasobiliary drainage tube was inserted, and the patient was treated conservatively. He was discharged on day 83 of hospitalization. Although using preoperative contrast-enhanced computed tomography before damage control surgery remains controversial, it can provide useful information to determine damage control strategy, including morphological evaluation of the injured area and the presence of active bleeding.

Early stoma closure after low anterior resection is not recommended due to postoperative complications and asymptomatic anastomotic leakage.

The safety of early stoma closure after lower anterior resection (LAR) for rectal cancer remains controversial. In this study, patients scheduled to undergo LAR and stoma creation for rectal cancer were recruited. In absence of anastomotic leakage on radiological examination, closure of the diverting ileostomy was performed within 2 weeks. The primary endpoint was incidence of the colorectal anastomosis leakage after early stoma closure. Because of the slow accrual rate, the study was closed before recruitment reached the planned number of patients (n = 20). Among the 13 patients enrolled between April 2019 and March 2021, early stoma closure was performed in seven patients (53.8%). Non-clinical anastomotic leakage, leakage identified only on radiological examination, occurred in five cases, resulting in rescheduling of stoma closure. One patient did not undergo early stoma closure due to ileus. After stoma closure, colorectal anastomotic leakage manifested in one case; its incidence rate was 14.2%. Surgical site infection occurred in 42.8% of patients. This study revealed that asymptomatic anastomotic leakage occurred frequently. Considering the low rate of successful cases and the high rate of complications, early stoma closure within 2 weeks after LAR should not be performed routinely. Trial registration: (UMIN000036382 registered on 03/04/2019).

Sepsis-Associated Muscle Wasting: A Comprehensive Review from Bench to Bedside.

Sepsis-associated muscle wasting (SAMW) is characterized by decreased muscle mass, reduced muscle fiber size, and decreased muscle strength, resulting in persistent physical disability accompanied by sepsis. Systemic inflammatory cytokines are the main cause of SAMW, which occurs in 40-70% of patients with sepsis. The pathways associated with the ubiquitin-proteasome and autophagy systems are particularly activated in the muscle tissues during sepsis and may lead to muscle wasting. Additionally, expression of muscle atrophy-related genes Atrogin-1 and MuRF-1 are seemingly increased via the ubiquitin-proteasome pathway. In clinical settings, electrical muscular stimulation, physiotherapy, early mobilization, and nutritional support are used for patients with sepsis to prevent or treat SAMW. However, there are no pharmacological treatments for SAMW, and the underlying mechanisms are still unknown. Therefore, research is urgently required in this field.

Possible Use of Non-purine Selective Xanthine Oxidoreductase Inhibitors for Prevention of Exercise-induced Acute Kidney Injury Associated with Renal Hypouricemia.

Exercise-induced acute kidney injury (EIAKI) is frequently complicated with renal hypouricemia (RHUC). In patients with RHUC, limiting anaerobic exercise can prevent EIAKI. However, it is challenging to reduce exercise intensity in athletes. We herein report a 16-year-old Japanese football player with familial RHUC with compound heterozygous mutations in urate transporter 1 (URAT1) who presented with recurrent EIAKI. As prophylaxis (hydration during exercise) could not prevent EIAKI, febuxostat was initiated. EIAKI was not observed for 16 months despite exercising intensively. Hence, non-purine-selective xanthine oxidoreductase inhibitors may decrease the incidence of EIAKI in athletes with RHUC.

The mechanism and significance of the conversion of xanthine dehydrogenase to xanthine oxidase in mammalian secretory gland cells.

The conversion of xanthine dehydrogenase (XDH) to xanthine oxidase (XO) occurs only in mammalian species. In fresh bovine milk, the enzyme exists predominantly as the oxidase form, in contrast to various normal organs where it is found primarily as the dehydrogenase: the mechanism of conversion to the oxidase in milk remains obscure. A systematic search for the essential factors for conversion from XDH to XO has been performed within fresh bovine milk using the highly purified dehydrogenase form after removal endogenous oxidase form by fractionation analysis. We find that conversion to the oxidase form requires four components under air: lactoperoxidase (LPO), XDH, SCN-, and substrate hypoxanthine or xanthine; the contribution of sulfhydryl oxidase appears to be minor. Disulfide bond formation between Cys-535 and Cys-995 is principally involved in the conversion, consistent with the result obtained from previous work with transgenic mice. In vitro reconstitution of LPO and SCN- results in synergistic conversion of the dehydrogenase to the oxidase the presence of xanthine, indicating the conversion is autocatalytic. Milk from an LPO knockout mouse contains a significantly greater proportion of the dehydrogenase form of the enzyme, although some oxidase form is also present, indicating that LPO contributes principally to the conversion, but that sulfhydryl oxidase (SO) may also be involved to a minor extent. All the components XDH/LPO/SCN- are necessary to inhibit bacterial growth in the presence of xanthine through disulfide bond formation in bacterial protein(s) required for replication, as part of an innate immunity system in mammals. Human GTEx Data suggest that mRNA of XDH and LPO are highly co-expressed in the salivary gland, mammary gland, mucosa of the airway and lung alveoli, and we have confirmed these human GTEx Data experimentally in mice. We discuss the possible roles of these components in the propagation of SARS-CoV-2 in these human cell types.

Free Jejunal Graft Interposition with Vascular Reconstruction in Patients Undergoing Pharyngo Laryngo Esophagectomy.

BACKGROUND: Pharyngo-esophageal reconstruction using free jejunal grafts has been widely used for the treatment of locally advanced carcinomas of the hypopharynx and cervical esophagus. However, the procedure is technically demanding and requires complex recontractions. The aim of this study was to evaluate our institutional outcomes of reconstruction using a free jejunal graft with vascular reconstruction in patients undergoing pharyngo laryngo esophagectomy with a multidisciplinary surgical team. METHODS: There were 90 consecutive patients between October 2006 and February 2021. The mean age was 64.6 ± 10.3 years, and there were 76 male patients. Of 90 patients, 49 underwent preoperative chemotherapy and/or radiotherapy. Jejunal vessels were commonly anastomosed to the common carotid artery and the internal jugular vein (77.8% and 92.2%, respectively). Continuous intravenous infusion of heparin was used postoperatively. RESULTS: Necrosis of the graft was observed in 5 patients. An isolated revision of vein was necessary in 1 patient. In all cases of graft failure, heparin was not used postoperatively. On the other hand, among the patients without graft failure, heparin was used for about two-thirds of the patients and was significantly different (0% vs. 66%, P = 0.01). CONCLUSIONS: Free jejunal graft with vessel reconstruction is a safe and effective method for patients undergoing pharyngo laryngo esophagectomy. The position for the prevention of kinking as well anastomosis maneuver of vein is especially important. Moreover, early postoperative anticoagulation is essential.

Assessing the impact of watershed characteristics and management on nutrient concentrations in tropical rivers using a machine learning method.

Excessive loadings of terrestrial nitrogen and phosphorus, as well as their imbalances with silicon, have been recognized as one of the major causes of water quality and ecosystem deterioration in receiving waters. In this study, a periodic water quality monitoring was conducted in the rivers and streams of a tropical island (Ishigaki Island, Japan) to identify the factors controlling the concentrations of dissolved inorganic nitrogen (DIN), total phosphorus (TP) and dissolved silicon (DSi) with a special focus on the catchment characteristics (e.g., land use, surface geology, topography). Random Forest (RF) machine learning algorithm was employed to develop predictive models for nutrient concentrations from the catchment properties. The developed models could predict nutrient concentrations with sufficient accuracy, demonstrating that the studied nutrients are strongly affected by catchment properties. Agricultural land uses (e.g., livestock barn, sugarcane field) were ranked as the most important parameters for DIN and TP, while broadleaf forest was the most influential factor for DSi. Using the RF models, the contributions of DIN originating from sugarcane fields (i.e., fertilizers) and barns (i.e., manure) to riverine DIN were estimated, which were up to 60% in total in the studied river basins. Furthermore, the yield of DIN from sugarcane fields, calculated as the concentration of DIN derived from sugarcane fields divided by the percent area of sugarcane fields, strongly positively correlated with the areal coverage of limestone, suggesting that fertilizer-derived DIN is more prone to leaching out from cropland soil to groundwater and rivers in catchments with a higher dominance of calcareous geology. These results, including the methodology employed, have implications for water quality assessment and management in inland and coastal waters not only at the study site but also other regions.