Distinct features of SARS-CoV-2 humoral immunity against Omicron breakthrough infection.

BACKGROUND: SARS-CoV-2 Omicron breakthrough infection (Omicron-BTI) after vaccination has been frequently observed. A more detailed understanding of the humoral immunity against Omicron-BTI is required. METHODS: We measured strain-specific live-virus based neutralizing activity, anti-spike IgG, and anti-receptor-binding domain (RBD) IgG titers in individuals with Omicron/BA.1-BTI and directly compared them with controls with diverse combinations of wild-type (WT) mRNA vaccination and infection history. RESULTS: Omicron-BTI individuals showed markedly higher neutralizing titers against all the WT, Delta, and Omicron strains in convalescent sera, compared with unvaccinated Omicron-infection individuals with only Omicron neutralizing activity. Similar tendencies were found in strain-specific anti-spike and anti-RBD IgG titers. The Omicron-specificity (BA.1/WT neutralizing ratio), Omicron-neutralizing efficiency per antibody unit, and anti-Omicron RBD-directivity of anti-spike antibodies in Omicron-BTI individuals were all significantly lower than those in unvaccinated Omicron-infection individuals, but they were equivalent to or higher than those in uninfected vaccinees. The induction of Omicron-specific neutralizing activity after Omicron-BTI was not weakened for eight months from the last vaccination. CONCLUSIONS: These findings suggest that cross-reactive vaccine-induced immunity was intensively stimulated following Omicron breakthrough infection, which contributed to Omicron neutralization. Measuring SARS-CoV-2 variant-specific antibody levels as well as neutralizing activity is useful for evaluating humoral immunity after breakthrough infection in the current situation of antigenic gaps between vaccinated and epidemic (Omicron sub-lineages) strains.

SARS-CoV-2 strain-specific anti-spike IgG ELISA utilizing spike protein produced by silkworms.

BACKGROUND: A cost-effective and eco-friendly method is needed for the assessment of humoral immunity against SARS-CoV-2 in large populations. OBJECTIVE: We investigated the performance of an ELISA that uses silkworm-produced proteins to quantify the strain-specific anti-Spike IgG (anti-S IgG) titer. METHODS: The OD values for the anti-His-tag antibody, a standard material of ELISA quantification, were measured. Correlations between the ELISA for each strain and the Abbott SARS-CoV-2 IgG II Quant assay for the wild type were evaluated with serum samples from nine participants with various infection and vaccination statuses. RESULTS: Linear dose-responses were confirmed by high coefficients of determination: 0.994, 0.994, and 0.996 for the wild-type, Delta, and Omicron (BA.1) strain assays, respectively. The coefficient of determination for the wild-type and Delta strain assays was high at 0.959 and 0.892, respectively, while the Omicron strain assay had a relatively low value of 0.563. Booster vaccinees showed similar or higher titers against all strains compared to infected persons without vaccination. The Omicron-infected persons without vaccination had lower antibody titers against wild type than did the vaccinated persons. CONCLUSIONS: This study provides data indicating that the ELISA with silkworm-produced proteins makes it possible to discriminate and quantify the strain-specific anti-S IgG antibody induced by vaccination or infection.

High yield production of norovirus GII.4 virus-like particles using silkworm pupae and evaluation of their protective immunogenicity.

Noroviruses (NoVs) are one of the major causes of acute viral gastroenteritis in humans. Virus-like particles (VLPs) without genomes that mimic the capsid structure of viruses are promising vaccine candidates for the prevention of NoVs infection. To produce large amounts of recombinant protein, including VLPs, the silkworm-expression vector system (silkworm-BEVS) is an efficient and powerful tool. In this study, we constructed a recombinant baculovirus that expresses VP1 protein, the major structural protein of NoV GII.4. Expression analysis showed that the baculovirus-infected silkworm pupae expressed NoV VP1 protein more efficiently than silkworm larval fat bodies. We obtained about 4.9 mg of purified NoV VP1 protein from only five silkworm pupae. The purified VP1 protein was confirmed by dynamic light scattering and electron microscopy to form VLPs of approximately 40 nm in diameter. Antisera from mice immunized with the antigen blocked NoV VLPs binding to histo-blood group antigens of pig gastric mucin and also blocked NoV infection in intestinal epithelial cells derived from human induced pluripotent stem (iPS) cells. Our findings demonstrated that NoV VLP eliciting protective antibodies could be obtained in milligram quantities from a few silkworm pupae using the silkworm-BEVS.

Autoimmune gastritis concomitant with gastric adenoma and subacute combined degeneration of the spinal cord.

A 62-year-old woman was referred to our department for further investigation of anaemia. Blood test showed macrocytic anaemia. Oesophagogastroduodenoscopy (OGD) revealed proximal-predominant gastric atrophy and flat elevated lesion in the gastric body. Several days after OGD, she complained of gait disturbance and was diagnosed with subacute combined degeneration of the spinal cord. Furthermore, laboratory tests showed positive for both anti-parietal cell and anti-intrinsic factor antibodies, as well as increased serum gastrin level and decreased pepsinogen I level, which confirmed the diagnosis of autoimmune gastritis (AIG). Anaemia and neurological symptoms were improved after vitamin B12 supplementation. Subsequently, the patient underwent gastric endoscopic submucosal dissection; histopathological examination revealed gastric adenoma. AIG can cause gastric neoplasms and vitamin B12 deficiency, with the latter resulting in pernicious anaemia and neurological disorders. These diseases are treatable but potentially life-threatening. This case highlights the importance of early diagnosis of AIG and proper management of its comorbidities.

Successful treatment with endoscopic transpapillary drainage for gallbladder perforation associated with steroid treatment for interstitial pneumonia (with video).

This case report highlights the clinical efficacy of endoscopic transpapillary drainage for gallbladder perforation in a high-risk surgical patient with a history of steroid treatment for interstitial pneumonia. The usefulness of endoscopic transpapillary gallbladder drainage in high-risk surgical patients with acute cholecystitis has not been established. In difficult cases of emergent surgery, such as described here, endoscopic transpapillary drainage is a promising method to manage gallbladder perforation and acute cholecystitis recurrence.

Approaches of validation of a 2-week combined repeated oral dose toxicity study with plasma micro sampling toxicokinetics (PMS-TK) in common marmosets.

We investigated the viability of a combined repeated dose toxicity study, including toxicokinetics (TK), in common marmosets according to the ICH-S4, ICH-S3A and ICH-S7A Guidelines using valsartan as test article whose non-clinical repeated dose toxicity studies had been conducted using this species for regulatory purpose. Valsartan was administered orally to 3 animals/sex at 200 mg/kg/day for 2 weeks. In addition to the routine parameters in repeated dose toxicity studies, safety pharmacology parameters (examinations of the central nervous, respiratory and cardiovascular systems) were also evaluated. The Plasma Micro Sampling Toxicokinetics (PMS-TK) method required ultrasensitive quantitation, was employed to evaluate the relationship between toxic changes and plasma concentrations as well as the effects of frequent blood sampling in individual animals. In valsartan, toxic findings (a deteriorated physical condition; moribundity of one male and one female on Day 14; sporadic vomitus; decreases in body weights and food consumption; decreases in erythrocytic parameters; and renal changes such as an increase in urea nitrogen, dilation of the tubules and hypertrophy of the tubular epithelium) were similar and plasma concentrations comparable to the results in the approval information. Furthermore, no side effects caused by frequent blood sampling were confirmed in the negative control group. Consequently, a combined repeated dose toxicity study including TK analysis using the PMS-TK method is viable in common marmosets and contributes to animal welfare.

Current Ventilator and Oxygen Management during General Anesthesia: A Multicenter, Cross-sectional Observational Study.

BACKGROUND: Intraoperative oxygen management is poorly understood. It was hypothesized that potentially preventable hyperoxemia and substantial oxygen exposure would be common during general anesthesia. METHODS: A multicenter, cross-sectional study was conducted to describe current ventilator management, particularly oxygen management, during general anesthesia in Japan. All adult patients (16 yr old or older) who received general anesthesia over 5 consecutive days in 2015 at 43 participating hospitals were identified. Ventilator settings and vital signs were collected 1 h after the induction of general anesthesia. We determined the prevalence of potentially preventable hyperoxemia (oxygen saturation measured by pulse oximetry of more than 98%, despite fractional inspired oxygen tension of more than 0.21) and the risk factors for potentially substantial oxygen exposure (fractional inspired oxygen tension of more than 0.5, despite oxygen saturation measured by pulse oximetry of more than 92%). RESULTS: A total of 1,786 patients were found eligible, and 1,498 completed the study. Fractional inspired oxygen tension was between 0.31 and 0.6 in 1,385 patients (92%), whereas it was less than or equal to 0.3 in very few patients (1%). Most patients (83%) were exposed to potentially preventable hyperoxemia, and 32% had potentially substantial oxygen exposure. In multivariable analysis, old age, emergency surgery, and one-lung ventilation were independently associated with increased potentially substantial oxygen exposure, whereas use of volume control ventilation and high positive end-expiratory pressure levels were associated with decreased potentially substantial oxygen exposure. One-lung ventilation was particularly a strong risk factor for potentially substantial oxygen exposure (adjusted odds ratio, 13.35; 95% CI, 7.24 to 24.60). CONCLUSIONS: Potentially preventable hyperoxemia and substantial oxygen exposure are common during general anesthesia, especially during one-lung ventilation. Future research should explore the safety and feasibility of a more conservative approach for intraoperative oxygen therapy.

Toward the Atomic-Level Mass Analysis of Biomolecules by the Scanning Atom Probe.

In 1994, a new type of atom probe instrument, named the scanning atom probe (SAP), was proposed. The unique feature of the SAP is the introduction of a small extraction electrode, which scans over a specimen surface and confines the high field, required for field evaporation of surface atoms in a small space, between the specimen and the electrode. Thus, the SAP does not require a sharp specimen tip. This indicates that the SAP can mass analyze the specimens which are difficult to form in a sharp tip, such as organic materials and biomolecules. Clean single wall carbon nanotubes (CNT), made by high-pressure carbon monoxide process are found to be the best substrates for biomolecules. Various amino acids and dipeptide biomolecules were successfully mass analyzed, revealing characteristic clusters formed by strongly bound atoms in the specimens. The mass analysis indicates that SAP analysis of biomolecules is not only qualitative, but also quantitative.

[Effect of Water Intake on Allergy-like Events Associated with Non-ionic Iodine Contrast Agents].

The use of iodine contrast agents occasionally causes serious allergic symptoms including anaphylaxis. At Kyoto University Hospital to prevent nephropathy we began recommending water intake before and after administration of iodine contrast agents in September 2012. In the present study we investigated the effect of water intake on the incidence of allergy-like events after the use of non-ionic iodine contrast agents. We extracted the occurrence of allergy-like events from the incident report system in our hospital from January 2011 to September 2014, and classified these events into the following 3 grades: 1+ (follow-up); 2+ (medication treatment); and 3+ (hospitalization). The allergy-like incidence rate was calculated for subsequent evaluation according to season and water intake. Allergy-like events significantly decreased from 0.49% before the recommendation of water intake to 0.26% at 1 year and 0.20% at 2 years after implementing the recommendation. The incidence of allergy-like events was significantly higher in summer than in winter before water intake was recommended. After implementing the recommendation, the value for summer significantly decreased to an incidence similar to that of winter. Respiratory and gastrointestinal allergy-like symptoms were dramatically decreased after implementing the recommendation. Water intake may be useful for preventing allergy-like events associated with non-ionic iodine contrast agents, especially during the summer.

Effects of auxiliary ligands of Pd(II) dimers on induction of chiral nematic phases: chirality inversion and the photo-responsive structural change.

Dinuclear square planar palladium(ii) complexes, [{Pd(ii)La}2(baet)] (La(-) = ß-diketonato and baet(2-) = 1,2-diacetyl-1,2-bis(3-methylbutanoyl)ethanato), were prepared and used as chiral dopants to induce chiral nematic phases. The following ß-diketones were used as LaH: pentane-2,4-dione (acacH), dibenzoylmethane (dbmH), di-4-nonyloxybenzoylmethane (C9-dbmH) and 3-[4'-(4''-(octyloxy)phenylazo)phenyl]-2,4-dione (C8-azoacacH). When the enantiomers were doped in a nematic liquid crystal, they induced a chiral nematic phase with a helical twisting power (HTP) of 5-50 µm(-1). In particular, the sample doped with [{Pd(ii)(C8-azoacac)}2(baet)] exhibited a reversible change of the circular dichroism spectrum under alternate irradiation at 350 nm and 460 nm. It implied that the HTP changed reversibly in response to the cis-trans isomerization of the coordinated C8-azoacac ligand.

[Triexponential diffusion analysis in invasive ductal carcinoma and fibroadenoma].

To simultaneously obtain information on diffusion and perfusion in breast lesions by diffusion-weighted magnetic resonance imaging (DWI), we analyzed three diffusion components using a triexponential function. Eighteen subjects [10 with invasive ductal carcinoma (IDC), 8 with fibroadenoma] were evaluated using DWI with multiple b-values. We derived perfusion-related diffusion, fast free diffusion, and slow restricted diffusion coefficients (Dp, Df, Ds) calculated from the triexponential function using the DWI data. Moreover, the triexponential analysis was compared with biexponential and monoexponential analyses. Each diffusion coefficient with a triexponential function was correlated to a relative enhancement ratio (RER) using dynamic contrast-enhanced MRI. In triexponential analysis, Dp and Ds in IDC were significantly higher than those for fibroadenoma. There was no correlation between each diffusion coefficient from the triexponential analysis in any of the groups (Dp, Df, and Ds), but biexponential analysis revealed a positive correlation between each diffusion coefficient in breast lesions. Strong correlations were found between Dp and RERs. Triexponential analysis thus makes it possible to obtain, in noninvasive fashion, more detailed diffusion and perfusion information in breast lesions.

Expression and purification of mouse peptide ESP4 in Escherichia coli.

Pheromones are species-specific chemical signals that regulate a wide range of social and sexual behaviors in many animals. In mice, the male-specific peptide ESP1 (exocrine gland-secreting peptide 1) is secreted into tear fluids and enhances female sexual receptive behavior. ESP1 belongs to the ESP family, a multigene family with 38 genes in mice. ESP1 shares the highest homology with ESP4. ESP1 is expressed in the extraorbital lacrimal gland, whereas ESP4 is expressed in some exocrine glands. Thus, ESP4 is expected to have a function that has not been elucidated yet. Large amounts of the purified ESP4 protein are required for structural and biochemical studies. Here we present an expression and purification scheme for the recombinant ESP4 protein. The N-terminally histidine-tagged ESP4 fusion protein was expressed in Escherichia coli as inclusion bodies, which were solubilized and purified by nickel affinity chromatography. The histidine tag was cleaved with thrombin and removed by a second nickel affinity chromatography step. The ESP4 protein was isolated with high purity by reversed-phase chromatography. For NMR analyses, we prepared a stable isotope-labeled ESP4 protein. Three repeated freeze-drying steps after the reversed-phase chromatography were required, to remove a volatile contaminating compound and to obtain an NMR spectrum with a homogeneous line shape. AMS-modification and far-UV CD spectroscopic analyses suggested that ESP4 has an intramolecular disulfide bridge and a helical structure, respectively. The present study provides a powerful tool for structural and biochemical studies of ESP4, leading toward the elucidation of the roles of the ESP family members.

Backbone and side-chain ¹H, ¹5N and ¹³C assignments of mouse peptide ESP4.

A peptide or a small protein released from an exocrine gland or in urine is utilized as a chemosignal that elicits social or reproductive behavior in mice. Recently, we identified the male-specific peptide, exocrine gland-secreting peptide 1 (ESP1), in mouse tear fluids that enhanced female sexual receptive behavior, and determined the three dimensional structure. ESP1 appears to be a member of multigene family that consists of 38 genes in mice, which we call the ESP family. ESP4, a member of the ESP family, is expressed in various exocrine glands, and shows the highest sequence similarity with ESP1. Here, we report the NMR assignments of ESP4 which provides a basis for NMR analyses of this protein. Our results will give insight into structural relationships within the ESP family.

Chirality effects on core-periphery connection in a star-burst type tetranuclear Ru(III) complex: application of vibrational circular dichroism spectroscopy.

Vibrational circular dichroism (VCD) spectroscopy was applied to study the stereochemical properties of a star-burst type tetranuclear Ru(III) complex, Δ-(or Λ-)[{Δ-(or Λ-)-Ru(III)(acac)(2)(taet)}(3)Ru(III)] (acac = acetylacetonato; taet = tetraacetylethanato). By comparing the VCD spectra of eight diastereomeric enantiomers, it was shown that the spectra reflected the homo- or hetero-chiral nature of the bridging part connecting the central core and the peripheral region.

[Evaluation of crosstalk effect on spin-echo images at 1.5 and 3 T].

The purpose of this study is to evaluate the crosstalk effect on spin-echo (SE) images at 1.5 and 3 T MRI. We examined the influence of crosstalk by comparing the full width at half-maximum (FWHM) and slice profile of images of a wedge-shaped phantom for various slice gaps. We also assessed crosstalk effect in the brain by comparing image contrast among healthy volunteers (n=8). Among the subjects, the shapes of the slice profiles at 1.5 T were similar to those at 3 T for long repetition times (TRs); however, at shorter TRs, differences in slice profiles were observed among the subjects and were more apparent at 3 than at 1.5 T. The relative contrast between white matter and gray matter on T(1)-weighted images was lower at 3 than at 1.5 T. The crosstalk effect was strongest when the TR of the excitation pulse was short. The influence of the adjacent excitation pulse is important in the process of T(1) relaxation because T(1) values are greater at 3 T. In conclusion, the influence of crosstalk on SE T(1)-weighted images is greater at 3 than at 1.5 T.

[Anesthetic management of radical nephrectomy using cardiopulmonary bypass in patients with vena caval or atrial extension of renal cell carcinoma].

We experienced three cases of anesthesia for radical nephrectomy using cardiopulmonary bypass in patients with vena caval or atrial extension of renal cell carcinoma. Pulmonary thromboembolism (PTE) did not occur. One patient with preoperative hepatorenal dysfunction died of multiple organ failure. Other two patients were discharged in good condition. We must pay attention to treatment of intraoperative PTE and massive hemorrhage, prevention of organ damage, and presence of preoperative organ dysfunction.

Increased carbon monoxide concentration in exhaled air after surgery and anesthesia.

Heme oxygenase-1 (HO-1) is induced by oxidative stress and is thought to confer protection against oxidative tissue injuries. HO-1 catalyzes the conversion of the heme moiety of hemeproteins, such as hemoglobin, myoglobin, and cytochrome P450, to biliverdin, liberating carbon monoxide (CO) in the process. CO reacts with hemoglobin to form carboxyhemoglobin. In this study, to examine the effect of anesthesia and/or surgery on endogenous CO production, we measured the amount of exhaled CO and the arterial carboxyhemoglobin concentration of patients who underwent surgery under general or spinal anesthesia. Both CO and carboxyhemoglobin concentrations were significantly larger on the day after surgery than during the preoperative period (P < 0.05) and in the recovery room (P < 0.05), regardless of anesthesia. However, neither index differed between general and spinal anesthesia. These results suggest that oxidative stress caused by anesthesia and/or surgery may induce HO-1, which catalyzes heme to produce CO, leading to increased exhaled CO concentration.