Novel Virus Air Sampler Based on Electrostatic Precipitation and Air Sampling of SARS-CoV-2.

The assessment of airborne viruses in air is a critical step in the design of appropriate prevention and control measures. Hence, herein, we developed a novel wet-type electrostatic air sampler using a viral dissolution buffer containing a radical scavenging agent, and verified the concentration of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA in the air of hospital rooms inhabiting coronavirus disease 2019 (COVID-19) patients and public areas. RNA damage caused by corona discharge was negligible when Buffer AVL was used as the collecting electrode. The viral RNA concentration in the air of the room varied by patient: 3.9 × 103 copy/m3 on the 10th day after onset in a mild case and 1.3 × 103 copy/m3 on the 18th day in a severe case. Viral RNA levels were 7.8 × 102 and 1.9 × 102 copy/m3 in the air of the office and food court, respectively, where people removed their masks when eating and talking, but it remained undetected in the station corridor where all the people were wearing masks. The assessment of airborne SARS-CoV-2 RNA using the proposed sampler can serve as a basis for the safe discontinuation of COVID-19 isolation precautions to identify exposure hotspots and alert individuals at increased infection risks.

Functional analysis of the N-terminal region of Vibrio FlhG, a MinD-type ATPase in flagellar number control.

GTPase FlhF and ATPase FlhG are two key factors involved in regulating the flagellum number in Vibrio alginolyticus. FlhG is a paralogue of the Escherichia coli cell division regulator MinD and has a longer N-terminal region than MinD with a conserved DQAxxLR motif. The deletion of this N-terminal region or a Q9A mutation in the DQAxxLR motif prevents FlhG from activating the GTPase activity of FlhF in vitro and causes a multi-flagellation phenotype. The mutant FlhG proteins, especially the N-terminally deleted variant, were remarkably reduced compared to that of the wild-type protein in vivo. When the mutant FlhG was expressed at the same level as the wild-type FlhG, the number of flagella was restored to the wild-type level. Once synthesized in Vibrio cells, the N-terminal region mutation in FlhG seems not to affect the protein stability. We speculated that the flhG translation efficiency is decreased by N-terminal mutation. Our results suggest that the N-terminal region of FlhG controls the number of flagella by adjusting the FlhF activity and the amount of FlhG in vivo. We speculate that the regulation by FlhG, achieved through transcription by the master regulator FlaK, is affected by the mutations, resulting in reduced flagellar formation by FlhF.

[A Case of Small Cell Carcinoma of Esophagus in Which Long-Term Survival Was Achieved with Multimodal Treatment].

A 79-year-old man presented to our hospital with 1-month history of discomfort on swallowing and pain in the thoracodorsal region. Image investigation revealed a tumor lesion affecting the area from the lower esophagus to the gastric antrum, and small cell carcinoma of esophagus was diagnosed based on biopsy. He was treated with resection of the lower esophagus and the upper part of the stomach and a postoperative chemoradiotherapy. The patient follow-upwas without recurrence until a malignant lymphoma developed 4 years and 5 months after the surgery. Chemotherapy was provided for the malignant lymphoma, however, the patient died 6 years and 4 months after the surgery for small cell carcinoma of esophagus. Small cell endocrine carcinoma of the esophagus is a relatively rare disease and its prognosis is poor. In our patient, long-term survival was achieved with multimodal treatment, however malignant lymphoma developed during the follow-upp eriod. This is the second case of metachronous cancer after the treatment for small cell carcinoma of the esophagus in Japan, and it is considered to be extremely rare.

Biological characterization of expression quantitative trait loci (eQTLs) showing tissue-specific opposite directional effects.

Interpreting the susceptible loci documented by genome-wide association studies (GWASs) is of utmost importance in the post-GWAS era. Since most complex traits are contributed by multiple tissues, analyzing tissue-specific effects of expression quantitative trait loci (eQTLs) is a promising approach. Here we describe "opposite eQTL effects", i.e., gene expression effects of eQTLs that are in the opposite direction between different tissues, as the biologically meaningful annotations of genes and genetic variants for understanding the GWAS loci. The genes and single-nucleotide polymorphisms (SNPs) associated with the opposite eQTL effects (opp-multi-eQTL-Genes and opp-multi-eQTL-SNPs) were extracted from the largest eQTL database provided by the Genotype-Tissue Expression (GTEx) project (release version 7). The opposite eQTL effects were detected even between closely related tissues such as cerebellum and brain cortex, and a significant proportion of the genes having eQTLs were annotated as the opp-multi-eQTL-Genes (2,323 out of 31,212; 7.4%). The opp-multi-eQTL-SNPs showed locational enrichment at the transcription start site and also possible involvement of epigenetic regulation. The biological importance of the opposite eQTL effects was also assessed using the SNPs reported in GWASs (GWAS-SNPs), which demonstrated that a high proportion of the opp-multi-eQTL-SNPs are in linkage disequilibrium with the GWAS-SNPs (2,498 out of 9,290; 26.9%). Based on the results, the opposite eQTL effects can be a common phenomenon in the tissue-specific gene regulation with a possible contribution to the development of complex traits.

Biochemical analysis of GTPase FlhF which controls the number and position of flagellar formation in marine Vibrio.

FlhF controls the number and position of the polar flagellar formation of Vibrio species. FlhF, is a paralog of FtsY, a GTPase acting in the Sec membrane transport system of bacteria, and localizes at the cell pole. Mutations in the conserved GTPase motif of FlhF lost polar localization capability and flagellar formation. Vibrio FlhF has not, until now, been purified as soluble protein. Here, we report that addition of MgCl2 and GTP or GDP at the step of cell lysis greatly improved the solubility of FlhF, allowing us to purify it in homogeneity. Purified FlhF showed GTPase activity only in the presence of FlhG. Of twelve FlhF GTPase motif mutants showing reduced function, eleven were recovered as precipitate after the cell disruption. The E440K substitution could be purified and showed no GTPase activity even in the presence of FlhG. Interestingly an FlhF substitution in the putative catalytic residue for GTP hydrolysis, R334A, allowed normal flagellar formation although GTPase activity of FlhF was completely abolished. Furthermore, size exclusion chromatography of purified FlhF revealed that it forms dimers in the presence of GTP but exists as monomer in the presence of GDP. We speculate that the GTP binding allows FlhF to dimerize and localize at the pole where it initiates flagellar formation, and the GDP-bound form diffuses as monomer.

Suture-induced arthritis as a clinical mimicker of septic arthritis.

Foreign body-induced arthritis is a rare etiology of mono-arthritis. It should be suspected in the case of postoperative arthritis, even if some decades have passed since surgery. Histopathology of the tissues is required for a definitive diagnosis, and debridement is essential for complete recovery.

Direct single-molecule observations of DNA unwinding by SV40 large tumor antigen under a negative DNA supercoil state.

Superhelices, which are induced by the twisting and coiling of double-helical DNA in chromosomes, are thought to affect transcription, replication, and other DNA metabolic processes. In this study, we report the effects of negative supercoiling on the unwinding activity of simian virus 40 large tumor antigen (SV40 TAg) at a single-molecular level. The supercoiling density of linear DNA templates was controlled using magnetic tweezers and monitored using a fluorescent microscope in a flow cell. SV40 TAg-mediated DNA unwinding under relaxed and negative supercoil states was analyzed by the direct observation of both single- and double-stranded regions of single DNA molecules. Increased negative superhelicity stimulated SV40 TAg-mediated DNA unwinding more strongly than a relaxed state; furthermore, negative superhelicity was associated with an increased probability of SV40 TAg-mediated DNA unwinding. These results suggest that negative superhelicity helps to regulate the initiation of DNA replication.

Auroral molecular-emission effects on the atomic oxygen line at 777.4 nm.

One of the representative auroral emission lines that radiates from F-region heights and is measurable on the ground is the 777.4 nm line from excited atomic oxygen. This line has been adopted, along with another E-region emission line, for example 427.8 nm, to estimate the mean energy and total energy flux of precipitating auroral electrons. The influence of emissions from part of the molecular nitrogen band, which mainly radiate from E-region heights, should be carefully evaluated because it might overlap the 777.4 nm atomic oxygen line in the spectrum. We performed statistical analysis of auroral spectrograph measurements that were obtained during the winter of 2016-2017 in Tromsø, Norway, to derive the ratio of the intensity of the 777.4 nm atomic oxygen line to that of the net measurement through a typically used optical filter with a full width at half maximum of a few nm. The ratio had a negative trend against geomagnetic activity, with a primary distribution of 0.5-0.7 and a minimum value of 0.3 for the most active auroral condition in this study. This result suggests that the 30-50% emission intensities measured through the optical filter may be from the molecular nitrogen band.

Effects of Three Lipidated Oxytocin Analogs on Behavioral Deficits in CD38 Knockout Mice.

Oxytocin (OT) is a nonapeptide that plays an important role in social behavior. Nasal administration of OT has been shown to improve trust in healthy humans and social interaction in autistic subjects. As is consistent with the nature of a peptide, OT has some unfavorable characteristics: it has a short half-life in plasma and shows poor permeability across the blood-brain barrier. Analogs with long-lasting effects may overcome these drawbacks. To this end, we have synthesized three analogs: lipo-oxytocin-1 (LOT-1), in which two palmitoyl groups are conjugated to the cysteine and tyrosine residues, lipo-oxytocin-2 (LOT-2) and lipo-oxytocin-3 (LOT-3), which include one palmitoyl group conjugated at the cysteine or tyrosine residue, respectively. The following behavioral deficits were observed in CD38 knockout (CD38-/-) mice: a lack of paternal nurturing in CD38-/- sires, decreased ability for social recognition, and decreased sucrose consumption. OT demonstrated the ability to recover these disturbances to the level of wild-type mice for 30 min after injection. LOT-2 and LOT-3 partially recovered the behaviors for a short period. Conversely, LOT-1 restored the behavioral parameters, not for 30 min, but for 24 h. These data suggest that the lipidation of OT has some therapeutic benefits, and LOT-1 would be most useful because of its long-last activity.

Structure-specific effects of lipidated oxytocin analogs on intracellular calcium levels, parental behavior, and oxytocin concentrations in the plasma and cerebrospinal fluid in mice.

Oxytocin (OT) is a neuroendocrine nonapeptide that plays an important role in social memory and behavior. Nasal administration of OT has been shown to improve trust in healthy humans and social interaction in autistic subjects in some clinical trials. As a central nervous system (CNS) drug, however, OT has two unfavorable characteristics: OT is short-acting and shows poor permeability across the blood-brain barrier, because it exists in charged form in the plasma and has short half-life. To overcome these drawbacks, an analog with long-lasting effects is required. We previously synthesized the analog, lipo-oxytocin-1 (LOT-1), in which two palmitoyl groups are conjugated to the cysteine and tyrosine residues. In this study, we synthesized and evaluated the analogs lipo-oxytocin-2 (LOT-2) and lipo-oxytocin-3 (LOT-3), which feature the conjugation of one palmitoyl group at the cysteine and tyrosine residues, respectively. In human embryonic kidney-293 cells overexpressing human OT receptors, these three LOTs demonstrated comparably weak effects on the elevation of intracellular free calcium concentrations after OT receptor activation, compared to the effects of OT. The three LOTs and OT exhibited different time-dependent effects on recovery from impaired pup retrieval behavior in sires of CD38-knockout mice. Sires treated with LOT-1 showed the strongest effect, whereas others had no or little effects at 24 h after injection. These results indicated that LOTs have structure-specific agonistic effects, and suggest that lipidation of OT might have therapeutic benefits for social impairment.

From Peptides to Peptidomimetics: A Strategy Based on the Structural Features of Cyclopropane.

Peptidomimetics, non-natural mimicries of bioactive peptides, comprise an important class of drug molecules. The essence of the peptidomimetic design is to mimic the key conformation assumed by the bioactive peptides upon binding to their targets. Regulation of the conformation of peptidomimetics is important not only to enhance target binding affinity and selectivity, but also to confer cell-membrane permeability for targeting protein-protein interactions in cells. The rational design of peptidomimetics with suitable three-dimensional structures is challenging, however, due to the inherent flexibility of peptides and their dynamic conformational changes upon binding to the target biomolecules. In this Minireview, a three-dimensional structural diversity-oriented strategy based on the characteristic structural features of cyclopropane to address this challenging issue in peptidomimetic chemistry is described.

Destruction of biological particles using non-thermal plasma.

Mechanism of inactivation of bio-particles exposed to non-thermal plasma (NTP), namely, dielectric barrier discharge (DBD), and plasma jet (PJ), has been studied using E. coli, B. subtilis spore, S. cerevisiae and bacteriophages. States of different biological components were monitored during the course of inactivation. Analysis of green fluorescent protein, GFP, introduced into E. coli. or B. subtiles spore cells proved that radicals generated by NTP penetrate into microbes, destroying the cell membrane and finally damage the genes. We have evaluated the damage of the bacteriophages. Bacteriophage λ having double stranded DNA was exposed to DBD, then DNA was purified and subjected to in vitro DNA packaging reactions. The re-packaged phages consist of the DNA from discharged phages and brand-new coat proteins were proved to be active, indicating that the damage of coat proteins is responsible for inactivation. M13 phages having single stranded DNA were also examined with the same manner. In this case, damage to the DNA was as severe as that of the coat proteins. For practical applications, DBD showed very intense sterilization ability for B. Subtilis spore with the D-value of less than 10 s. This result indicates a possibility of application of NTP for quick sterilization.

Cyclopropane-Based Peptidomimetics Mimicking Wide-Ranging Secondary Structures of Peptides: Conformational Analysis and Their Use in Rational Ligand Optimization.

Detailed conformational analyses of our previously reported cyclopropane-based peptidomimetics and conformational analysis-driven ligand optimization are described. Computational calculations and X-ray crystallography showed that the characteristic features of cyclopropane function effectively to constrain the molecular conformation in a three-dimensionally diverse manner. Subsequent principal component analysis revealed that the diversity covers the broad chemical space filled by peptide secondary structures in terms of both main-chain and side-chain conformations. Based on these analyses, a lead stereoisomer targeting melanocortin receptors was identified, and its potency and subtype selectivity were improved by further derivatization. The presented strategy is effective not only for designing non-peptidic ligands from a peptide ligand but also for the rational optimization of these ligands based on the plausible target-binding conformation without requiring the three- dimensional structural information of the target and its peptide ligands.

Proposal of the Coagulation Score as a Predictor for Short-Term and Long-Term Outcomes of Patients with Resectable Gastric Cancer.

BACKGROUND: Systemic hemostasis and thrombosis activation has been implicated in tumor progression and metastasis. This study aimed to investigate the use of coagulation factors as a novel prediction method for postoperative outcomes after curative gastrectomy in patients with stage II/III gastric cancer (GC). METHODS: Overall, 126 patients with stage II/III GC who underwent gastrectomy between May 2003 and February 2016 were eligible for inclusion in the study. We retrospectively evaluated the predictive value of preoperative platelet count and plasma fibrinogen and d-dimer levels, and coagulation score (0: fibrinogen and d-dimer both below upper limits; 1: either fibrinogen or d-dimer over upper limits; 2: both fibrinogen and d-dimer over upper limits) for short- and long-term outcomes. RESULTS: Postoperative complications were significantly more frequent in patients with elevated preoperative d-dimer levels compared with those with normal d-dimer levels (26 vs. 10 %; p = 0.032). The prevalence of postoperative complications showed a stepwise increase in proportion to the coagulation score. Patients with a coagulation score of 2 had significantly larger tumors (p = 0.013) and significantly greater intraoperative blood loss (p = 0.004) than those who scored 0 or 1. Coagulation score showed the highest values distinguished high-risk patients in overall and disease-free survival, and a coagulation score of 2 was an independent prognostic factor for recurrence. Patients with a coagulation score of 2 experienced a significantly higher prevalence of liver metastasis as an initial recurrence than those who scored 0 or 1 (p = 0.019). CONCLUSIONS: The coagulation score is a simple and promising predictor for postoperative complications and recurrence after gastrectomy in stage II/III GC patients.

Usefulness of preoperative estimated glomerular filtration rate to predict complications after curative gastrectomy in patients with clinical T2-4 gastric cancer.

BACKGROUND: Gastrectomy with systemic lymphadenectomy is the standard of care for resectable gastric cancer (GC), but it is sometimes associated with postoperative morbidity. Predicting complications is therefore an essential part of risk management in clinical practice. The renal function is routinely evaluated before surgery by blood examinations to determine dose of medication and infusion. However, the value of various parameters of renal function in prediction of postoperative complications remain unclear. METHODS: We included 315 patients who underwent curative D2 gastrectomy for clinical T2-T4 GC without preoperative treatment, and evaluated the correlation between the incidence of postoperative complications and the indicators of renal function. RESULTS: Forty-three patients experienced clinically relevant postoperative complications. Estimated glomerular filtration rate (eGFR) showed a higher area under the curve for predicting complications compared with urea nitrogen, creatinine, and creatinine clearance. The optimal eGFR cutoff value was 63.2 ml/min/1.73 m2, and eGFR < 63.2 was an independent risk factor for postoperative complications in multivariable analysis (odds ratio 4.67; 95 % confidence interval 2.16-10.5; p < 0.001). Particularly, the incidence of anastomotic leakage was significantly higher in patients with eGFR < 63.2 than those with eGFR ≥ 63.2 (9.4 % vs. 3.5 %). eGFR < 63.2 was also associated with a higher incidence of postoperative complications independent of age, body mass index, operative procedure, and clinical disease stage. Postoperative hospital stay was significantly longer in the eGFR < 63.2 group. CONCLUSIONS: Preoperative eGFR is a simple and useful predictor for complications after gastrectomy in patients with GC and may improve clinical care and the process of obtaining informed consent.

Nutritional predictors for postoperative short-term and long-term outcomes of patients with gastric cancer.

Evidence indicates that impaired immunocompetence and nutritional status adversely affect short-term and long-term outcomes of patients with cancer. We aimed to evaluate the clinical significance of preoperative immunocompetence and nutritional status according to Onodera's prognostic nutrition index (PNI) among patients who underwent curative gastrectomy for gastric cancer (GC).This study included 260 patients with stage II/III GC who underwent R0 resection. The predictive values of preoperative nutritional status for postoperative outcome (morbidity and prognosis) were evaluated. Onodera's PNI was calculated as follows: 10 × serum albumin (g/dL) + 0.005 × lymphocyte count (per mm).The mean preoperative PNI was 47.8. The area under the curve for predicting complications was greater for PNI compared with the serum albumin concentration or lymphocyte count. Multivariate analysis identified preoperative PNI < 47 as an independent predictor of postoperative morbidity. Moreover, patients in the PNI < 47 group experienced significantly shorter overall and disease-free survival compared with those in the PNI ≥ 47 group, notably because of a higher prevalence of hematogenous metastasis as the initial recurrence. Subgroup analysis according to disease stage and postoperative adjuvant treatment revealed that the prognostic significance of PNI was more apparent in patients with stage II GC and in those who received adjuvant chemotherapy.Preoperative PNI is easy and inexpensive to determine, and our findings indicate that PNI served as a significant predictor of postoperative morbidity, prognosis, and recurrence patterns of patients with stage II/III GC.

Tumor Infiltrative Pattern Predicts Sites of Recurrence After Curative Gastrectomy for Stages 2 and 3 Gastric Cancer.

BACKGROUND: In East Asia, the tumor infiltrative pattern (INF) has been routinely evaluated by hematoxylin and eosin-stained sections as a pathologic characteristic of surgically resected specimens. METHODS: The infiltrative pattern of gastric cancer (GC) has been histopathologically classified as INFa (expansive growth), INFb (intermediate type) and INFc (infiltrative growth) according to the Japanese Classification of Gastric Carcinoma. The prognostic value and characteristics of the disease recurrence pattern for each INF type were assessed in 785 patients with various stages of GC and also in 243 patients with stages 2 and 3 GC. RESULTS: Comparison of the overall survival experienced by patients independently of stage showed that INF was significantly associated with prognosis. Specifically, peritoneal metastasis was present in 91 % of stage 4 patients in the INFc group, whereas hepatic metastasis was present in 39 % of stage 4 patients in the INFa and INFb group. After curative gastrectomy of patients with stages 2 or 3 GC, INF was not significantly associated with survival. The prevalence of peritoneal recurrence was significantly higher in the INFc group than in the INFa and INFb group, whereas the prevalence of hepatic recurrence was significantly higher in the INFa and INFb group than in the INFc group. Multivariate analysis identified INFc as an independent risk factor for peritoneal recurrence after curative gastrectomy. The association of the INF type with the incidence of peritoneal recurrence was observed with all disease stages regardless whether the patient was given adjuvant chemotherapy or not. CONCLUSIONS: Evaluation of the INF type shows promise for its role as a predictor of postoperative recurrence sites in patients with GC.

Predictive value of drain amylase content for peripancreatic inflammatory fluid collections after laparoscopic (assisted) distal gastrectomy.

BACKGROUND: Laparoscopic (assisted) distal gastrectomy (LDG) with radical lymphadenectomy for gastric cancer has been widely conducted, particularly in the Far East. Peripancreatic inflammatory fluid collection (PIFC) is a serious and frequent postoperative complication after LDG for gastric cancer. The aim of this study was to evaluate the diagnostic performance of drain amylase content (D-AMY) for clinically relevant PIFC after LDG. METHODS: Two hundred and sixty-four patients who underwent LDG with prophylactic drains were enrolled. The predictive value of D-AMY on postoperative day (POD) 1 and POD 3 in the diagnosis of PIFC was evaluated. RESULTS: Twenty (7.6 %) patients experienced postoperative PIFC. Area under the curve in terms of receiver operating characteristics curve analysis of D-AMY on POD 1 was 0.801, and the optimal cutoff value for prediction of PIFC was 904 IU/l, with 98.2 % negative predictive value. Another cutoff was proposed as 4078 IU/l, with 92.2 % specificity. Multivariable analyses identified D-AMY on POD 1 ≥900 and ≥4000 IU/l as independent diagnostic factors for PIFC. Among patients at high risk of PIFC (D-AMY on POD 1 ≥900 IU/l), those who on POD 3 retained D-AMY value in excess of 31.2 % of the D-AMY value on POD 1 were more likely to experience PIFC compared with those with a pronounced decrease in D-AMY. CONCLUSIONS: D-AMY on POD 1 serves as a predictive factor for clinically relevant PIFC after LDG. Time-dependent changes in D-AMY can also be used for determining management of drains in patients at high risk of PIFC.

Adverse Effects of Intraoperative Blood Loss on Long-Term Outcomes after Curative Gastrectomy of Patients with Stage II/III Gastric Cancer.

BACKGROUND/AIMS: Gastrectomy with systemic lymphadenectomy sometimes causes excessive bleeding even by experienced surgeons. The aim of this study was to evaluate how intraoperative estimated blood loss (EBL) affected the long-term outcomes after curative surgery of patients with stage II/III gastric cancer (GC). METHODS: This study included 203 patients with stage II/III GC who did not receive perioperative blood transfusion between 1999 and 2015. The optimal cutoff and the prognostic significance of EBL were determined retrospectively. RESULTS: The median EBL was 285 ml. Receiver operating characteristic curve analysis identified 400 ml as an optimal cutoff. Patients with EBL ≥400 ml were more likely to have hepatic relapse and worse prognosis compared to those with EBL <400 ml. EBL ≥400 ml was identified as an independent prognostic factor for mortality by multivariable analysis. When patients were subdivided according to administration of adjuvant chemotherapy, there was a significant difference between the EBL ≥400 and <400 ml groups in patients who underwent surgery alone, whereas the prognosis was similar for patients of both groups who received adjuvant chemotherapy. CONCLUSION: EBL serves as a useful predictor for risk stratification after curative gastrectomy in patients with stage II/III GC.

Fundamental study on a gene transfection methodology for mammalian cells using water-in-oil droplet deformation in a DC electric field.

We have developed a gene transfection method called water-in-oil droplet electroporation (EP) that uses a dielectric oil and a liquid droplet containing live cells and exogenous DNA. When a cell suspension droplet is placed between a pair of electrodes, an intense DC electric field can induce droplet deformation, resulting in an instantaneous short circuit caused by the droplet elongating and contacting the two electrodes simultaneously. Small transient pores are generated in the cell membrane during the short, allowing the introduction of exogenous DNA into the cells. The droplet EP was characterized by varying the following experimental parameters: applied voltage, number of short circuits, type of medium (electric conductivity), concentration of exogenous DNA, and size of the droplet. In addition, the formation of transient pores in the cell membrane during droplet EP and the transfection efficiency were evaluated.