Characteristics of neutralizing antibody titers of the SARS-CoV-2 vaccine in maintenance hemodialysis patients

AIMS

Hemodialysis patients have high COVID-19 severity and mortality rates. For this high-risk group of hemodialysis patients with SARS-CoV-2 infection, early SARS-CoV-2 vaccination is recommended to prevent infection and severe disease. Thus far, few reports have evaluated COVID-19 antibody titers in hemodialysis patients. In this study, we investigated the time course of antibody titers acquired by vaccination in patients on dialysis.

MATERIALS AND METHODS

The anti-SARS-CoV-2 spike protein S1 IgG (anti-SP-IgG) antibody titers were compared between 33 outpatient maintenance hemodialysis patients and 32 age- and sex-matched healthy subjects. Antibody tests were performed at five time points: 6 months after the 2nd vaccination, immediately before the 3rd vaccination (8 months after the 2nd vaccination), and 2 weeks, 1 month, and 3 months after the 3rd vaccination.

RESULTS

The dialysis patient group had significantly lower values of anti-SP-IgG antibody titers than the control group 6 months after the 2nd vaccination (433.7 ± 36.24 vs. 650.2 (427.2 - 759.4) (AU/mL), p = 0.006) and immediately before the 3rd vaccination (219.3 (129.4 - 423.4) vs. 443.3 (267.1 - 600.4) (AU/mL), p = 0.034), but no significant differences were observed after the 3rd vaccination (19,000.0 (11,000.0 - 3,6000.0) vs. 23,500.0 (20,250.0 - 29,000.0) (AU/mL), p = 0.538).

CONCLUSION

This study confirmed that patients undergoing hemodialysis were proven to have acquired sufficient antibody titers after the vaccination.

Characteristics of Month-by-Month Blood Pressure Variability in Patients on Hemodialysis

INTRODUCTION

Poor prognosis in hemodialysis (HD) patients is due to the increased prevalence of cardiovascular diseases among them. We previously reported that higher visit-by-visit blood pressure variability is associated with increased cardiovascular mortality in HD patients. This present study aimed to investigate the characteristics of month-by-month blood pressure variability (MMBPV) in these patients.

METHODS

A total of 324 maintenance HD patients, who could be followed up for 60 months, were recruited. We used standard deviation (SD), coefficient of variation (CV), and variation independent of the mean (VIM) in pre- and post-dialysis systolic blood pressure (pre- and post-SD, pre- and post-CV, and pre- and post-VIM) as an index of MMBPV. We investigated (1) the reproducibility of MMBPV, (2) relationship between these values and background factors, and (3) association between these values and mortality.

RESULTS

MMBPV (pre- and post-SD, pre- and post-CV, and pre- and post-VIM) showed significant reproducibility (intraclass correlation, 0.483 [p < 0.001], 0.553 [p < 0.001], 0.450 [p < 0.001], 0.518 [p < 0.001], 0.456 [p < 0.001], and 0.522 [p < 0.001], respectively). High pre-VIM was associated with high interdialytic weight gain and poor nutritional status. High post-VIM was associated with glucose intolerance, high interdialytic weight gain, and poor nutritional status and associated with high rate of cardiovascular deaths independent of other factors (hazard ratio: 1.104, 95% confidence interval: 1.011-1.207, p = 0.028).

CONCLUSION

These data suggested that pre- and post-VIM in HD patients are reproducible and associated with various background factors, and especially post-VIM is independently correlated with cardiovascular mortality. Further studies are necessary to confirm the mechanism of increased post-VIM and clarify whether reducing post-VIM can improve the prognosis of HD patients.

Erratum: Search for Cosmic-Ray Boosted Sub-GeV Dark Matter Using Recoil Protons at Super-Kamiokande [Phys. Rev. Lett. 130, 031802 (2023)]

This corrects the article DOI: 10.1103/PhysRevLett.130.031802.

Measurements of neutrino oscillation parameters from the T2K experiment using 3.6×1021 protons on target

The T2K experiment presents new measurements of neutrino oscillation parameters using 19.7 ( 16.3 ) × 10 20 protons on target (POT) in (anti-)neutrino mode at the far detector (FD). Compared to the previous analysis, an additional 4.7 × 10 20 POT neutrino data was collected at the FD. Significant improvements were made to the analysis methodology, with the near-detector analysis introducing new selections and using more than double the data. Additionally, this is the first T2K oscillation analysis to use NA61/SHINE data on a replica of the T2K target to tune the neutrino flux model, and the neutrino interaction model was improved to include new nuclear effects and calculations. Frequentist and Bayesian analyses are presented, including results on sin 2 θ 13 and the impact of priors on the δ CP measurement. Both analyses prefer the normal mass ordering and upper octant of sin 2 θ 23 with a nearly maximally CP-violating phase. Assuming the normal ordering and using the constraint on sin 2 θ 13 from reactors, sin 2 θ 23 = 0 . 561 - 0.032 + 0.021 using Feldman-Cousins corrected intervals, and Δ m 32 2 = 2 . 494 - 0.058 + 0.041 × 10 - 3 eV 2 using constant Δ χ 2 intervals. The CP-violating phase is constrained to δ CP = - 1 . 97 - 0.70 + 0.97 using Feldman-Cousins corrected intervals, and δ CP = 0 , π is excluded at more than 90% confidence level. A Jarlskog invariant of zero is excluded at more than 2 σ credible level using a flat prior in δ CP , and just below 2 σ using a flat prior in sin δ CP . When the external constraint on sin 2 θ 13 is removed, sin 2 θ 13 = 28 . 0 - 6.5 + 2.8 × 10 - 3 , in agreement with measurements from reactor experiments. These results are consistent with previous T2K analyses.

Search for Cosmic-Ray Boosted Sub-GeV Dark Matter Using Recoil Protons at Super-Kamiokande

We report a search for cosmic-ray boosted dark matter with protons using the 0.37  megaton×years data collected at Super-Kamiokande experiment during the 1996-2018 period (SKI-IV phase). We searched for an excess of proton recoils above the atmospheric neutrino background from the vicinity of the Galactic Center. No such excess is observed, and limits are calculated for two reference models of dark matter with either a constant interaction cross section or through a scalar mediator. This is the first experimental search for boosted dark matter with hadrons using directional information. The results present the most stringent limits on cosmic-ray boosted dark matter and exclude the dark matter-nucleon elastic scattering cross section between 10^{-33}cm^{2} and 10^{-27}cm^{2} for dark matter mass from 1  MeV/c^{2} to 300  MeV/c^{2}.

Modeling Low Muscle Mass Screening in Hemodialysis Patients

<b><i>Introduction:</i></b> Computed tomography (CT) can accurately measure muscle mass, which is necessary for diagnosing sarcopenia, even in dialysis patients. However, CT-based screening for such patients is challenging, especially considering the availability of equipment within dialysis facilities. We therefore aimed to develop a bedside prediction model for low muscle mass, defined by the psoas muscle mass index (PMI) from CT measurement. <b><i>Methods:</i></b> Hemodialysis patients (<i>n</i> = 619) who had undergone abdominal CT screening were divided into the development (<i>n</i> = 441) and validation (<i>n</i> = 178) groups. PMI was manually measured using abdominal CT images to diagnose low muscle mass by two independent investigators. The development group’s data were used to create a logistic regression model using 42 items extracted from clinical information as predictive variables; variables were selected using the stepwise method. External validity was examined using the validation group’s data, and the area under the curve (AUC), sensitivity, and specificity were calculated. <b><i>Results:</i></b> Of all subjects, 226 (37%) were diagnosed with low muscle mass using PMI. A predictive model for low muscle mass was calculated using ten variables: each grip strength, sex, height, dry weight, primary cause of end-stage renal disease, diastolic blood pressure at start of session, pre-dialysis potassium and albumin level, and dialysis water removal in a session. The development group’s adjusted AUC, sensitivity, and specificity were 0.81, 60%, and 87%, respectively. The validation group’s adjusted AUC, sensitivity, and specificity were 0.73, 64%, and 82%, respectively. <b><i>Discussion/Conclusion:</i></b> Our results facilitate skeletal muscle screening in hemodialysis patients, assisting in sarcopenia prophylaxis and intervention decisions.

Identification of a polyphenol and its antioxidant properties from the roasting reaction of alginic acid

The radical scavenging activity of marine polysaccharides was enhanced by their high-temperature treatment (roasting reaction model). The product obtained from alginic acid exhibited maximum activity, and a radical scavenger, alginetin, was identified in the product. Its antioxidant activities were examined by chemical methods, which confirmed that it possessed a stoichiometrically greater antioxidant capacity than that of Trolox.

Bioactivity of alginetin, a caramelization product of pectin: Cytometric analysis of rat thymic lymphocytes using fluorescent probes

Alginetin is the major product formed from pentoses and hexurionic acids. Alginetin is producted by cooking process of food including pection, a naturally-occurring polysacharride found in many plants. However, the biological interaction and toxicity of alginetin are not known at all. The aim of the present study was to investigate the cellular actions of alginetin on rat thymic lymphocytes. The effects of alginetin on the cell were examined using flow cytometry with fluorescent probes. Alginetin increased cellular content of non-protein thiols ([NPT]i) and elevated intracellular Zn2+ levels ([Zn2+]i). Chelation of intracellular Zn2+ reduced the effect of alginetin on [NPT]i, and chelation of external Zn2+ almost completely diminished alginetin-induced elevation of [Zn2+]i, indicating that alginetin treatment increased Zn2+ influx. Increased [NPT]i and [Zn2+]i levels in response to alginetin were positively correlated. Alginetin protected cells against oxidative stress induced by hydrogen peroxide and Ca2+ overload by calcium ionophore. It is considered that the increases in [NPT]i and [Zn2+]i are responsible for the cytoprotective activity of alginetin because NPT attenuates oxidative stress and Zn2+ competes with Ca2+. Alginetin may be produced during manufacturing of jam, which may provide additional health benefits of jam.

Impact of frailty on super elderly patients with peripheral artery disease from the I-PAD 3 year registry

Background

Unlike age, frailty is often not taken into account in treatment indications of Endovascular treatment (EVT). One of the reason is that there was little known the relationship between frailty and the outcome of EVT for super elderly patients with peripheral artery disease (PAD). We investigate impacts of frailty on the super elderly patient prognosis who underwent EVT.

Purpose

To investigate impacts of frailty on the super elderly patient prognosis who underwent EVT.

Methods

From August 2015 to July 2016, 335 consecutive patients who underwent EVT were enrolled in the I-PAD registry from 7 institutes in Nagano prefecture. Among them, we selected and analyzed 91 super elderly PAD patients (≥80 years-old) and divided them into two groups:those with moderate or higher frailty (Clinical Frailty Scale (CFS) ≥6, n=28) and those without (CFS ≤5, n=63). The primary endpoints were cardiovascular death and major adverse cardiovascular and limb events (MACLE), defined as a composite of cardiovascular death, myocardial infarction, stroke, admission for heart failure, major amputation and revascularization.

Results

The median follow-up period was 2.7 years. Freedom rate from cardiovascular death and MACLE were significantly lower among patients with moderate or higher frailty than among those without (47.0% vs. 58.0%, P=0.03; 39.1% vs. 68.5%, P&lt;0.01).

Conclusion

The prognosis of super elderly patients with moderate or higher frailty is worse than those without.

Funding Acknowledgement

Type of funding source: None

Association between serum soluble (pro)renin receptor level and worsening of cardiac function in hemodialysis patients: A prospective observational study

The (pro)renin receptor ((P)RR) is cleaved to generate soluble (P)RR (s(P)RR), which reflects the status of the tissue renin-angiotensin system. Hemodialysis (HD) patients have a poor prognosis due to the increased prevalence of cardiovascular diseases. The present study aimed to investigate whether serum s(P)RR level is associated with the worsening of cardiac function in HD patients. A total of 258 maintenance HD patients were recruited and serum s(P)RR concentration was measured. Background factors in patients who survived (S group) and patients who died (D group) during the 12-month follow-up period and relationships between serum s(P)RR level and changes in cardiac function during the follow-up period in the S group were investigated. The median serum s(P)RR value at baseline was 29.8 ng/ml. Twenty-four patients died during the follow-up period. Cardiothoracic ratio, human atrial natriuretic peptide (hANP), brain natriuretic peptide (BNP), and E over e-prime were significantly higher in the D group. In the S group, changes in hANP or BNP were significantly greater in the higher serum s(P)RR group than in the lower serum s(P)RR group. High serum s(P)RR level was significantly correlated with changes in BNP, independent of other factors. High serum s(P)RR level was associated with increases in BNP, independent of other risk factors, suggesting that an increased expression of (P)RR may be associated with a progression of heart failure in HD patients and that serum s(P)RR concentration could be used as a biomarker for selecting patients requiring intensive care.

Search for Electron Antineutrino Appearance in a Long-Baseline Muon Antineutrino Beam

Electron antineutrino appearance is measured by the T2K experiment in an accelerator-produced antineutrino beam, using additional neutrino beam operation to constrain parameters of the Pontecorvo-Maki-Nakagawa-Sakata (PMNS) mixing matrix. T2K observes 15 candidate electron antineutrino events with a background expectation of 9.3 events. Including information from the kinematic distribution of observed events, the hypothesis of no electron antineutrino appearance is disfavored with a significance of 2.40σ and no discrepancy between data and PMNS predictions is found. A complementary analysis that introduces an additional free parameter which allows non-PMNS values of electron neutrino and antineutrino appearance also finds no discrepancy between data and PMNS predictions.

Triphenyltin disrupts intracellular Zn2+ homeostasis in rat thymic lymphocytes

Triphenyltin (TPT), previously used as an agricultural fungicide and industrial antifoulant, is now considered an environmental pollutant. The effect of TPT on human health is concerning due to its presence as a contaminant in seafood. In this study, the changes in intracellular Zn²⁺ concentration ([Zn²⁺]i) and cellular content of nonprotein thiols ([NPT]i) induced by triphenyltin chloride (TPTCH), were measured in rat thymic lymphocytes. This was studied by flow-cytometry using the fluorescent probes FluoZin-3-AM and 5-chloromethylfluorescein diacetate (5-CMF-DA). Incubation with TPTCH, at 0.1 μM or more (up to 3 μM), increased [Zn²⁺]i in a concentration-dependent manner. The TPTCH-induced elevation in [Zn²⁺]i was due to the increase in membrane Zn²⁺ permeability and intracellular Zn²⁺ release. Incubation with TPTCH at 0.3 μM significantly increased [NPT]i levels, whereas the addition of an intracellular Zn²⁺ chelator had no effect on the same. TPT at higher concentrations (1 or 3 μM) reduced [NPT]i. TPT may disturb intracellular Zn²⁺ signaling in lymphocytes that disturbs cellular functions.

Modification of cell vulnerability to oxidative stress by N-(3-oxododecanoyl)-L-homoserine-lactone, a quorum sensing molecule, in rat thymocytes

N-(3-oxododecanoyl)-l-homoserine-lactone (ODHL), a quorum sensing molecule, affects intracellular Zn²⁺ concentration ([Zn²⁺]i) and cellular levels of nonprotein thiols ([NPT]i) of rat thymic lymphocytes, both of which are assumed to affect cell vulnerability to oxidative stress. Therefore, it is interesting to examine the effects of ODHL on the cells under oxidative stress. ODHL augmented the cytotoxicity of H₂O₂, but not calcium ionophore A23187. ODHL potentiated the H₂O₂-induced elevation of [Zn²⁺]i, wherein, it greatly attenuated the H₂O₂-induced increase in intracellular Ca²⁺ concentration. ODHL did not affect [NPT]i in the presence of H₂O₂. Therefore, we conclude that the elevation of [Zn²⁺]i is involved in the ODHL-induced potentiation of H₂O₂ cytotoxicity. Our findings suggest that ODHL modifies cell vulnerability to oxidative stress in host cells.

Characteristics of visit-to-visit blood pressure variability in hemodialysis patients

Visit-to-visit blood pressure variability (VVBPV) is an independent risk factor for cardiovascular morbidity and mortality in the general population. Hemodialysis (HD) patients have a poor prognosis due to an increased prevalence of cardiovascular disease. Intradialytic hypotension is associated with excess mortality, but whether VVBPV influences mortality is still unclear in HD patients. The present study aimed to investigate the characteristics of VVBPV in these patients. A total of 324 maintenance HD patients, who could be followed for 60 months, were recruited. We used variation independent of the mean (VIM) in pre-dialysis systolic blood pressure (pre-VIM-SBP) as an index of VVBPV. We investigated (1) the reproducibility of pre-VIM-SBP, (2) the relationship between pre-VIM-SBP and background factors, and (3) the association between pre-VIM-SBP and mortality. Pre-VIM-SBP showed significant reproducibility [intraclass correlation, 0.45 (P < 0.001)]. Higher pre-VIM-SBP was associated with less physical activity and worse left ventricular diastolic function. Higher pre-VIM-SBP was associated with a higher rate of cardiovascular deaths independent of other factors. These data suggest that VVBPV in HD patients is reproducible and associated with various background factors. VVBPV is independently correlated with cardiovascular mortality (hazard ratio: 1.166, 95% confidence interval: 1.030-1.320, P = 0.015). Further studies are necessary to confirm the mechanism of increased VVBPV and to clarify whether reducing VVBPV will improve the prognosis for HD patients.

Search for CP Violation in Neutrino and Antineutrino Oscillations by the T2K Experiment with 2.2×10^{21} Protons on Target

The T2K experiment measures muon neutrino disappearance and electron neutrino appearance in accelerator-produced neutrino and antineutrino beams. With an exposure of 14.7(7.6)×10^{20} protons on target in the neutrino (antineutrino) mode, 89 ν_{e} candidates and seven anti-ν_{e} candidates are observed, while 67.5 and 9.0 are expected for δ_{CP}=0 and normal mass ordering. The obtained 2σ confidence interval for the CP-violating phase, δ_{CP}, does not include the CP-conserving cases (δ_{CP}=0, π). The best-fit values of other parameters are sin^{2}θ_{23}=0.526_{-0.036}^{+0.032} and Δm_{32}^{2}=2.463_{-0.070}^{+0.071}×10^{-3}  eV^{2}/c^{4}.

Captan-induced increase in the concentrations of intracellular Ca2+ and Zn2+ and its correlation with oxidative stress in rat thymic lymphocytes

Captan, a phthalimide fungicide, is considered to be relatively nontoxic to mammals. There is a possibility that captan affects membrane and cellular parameters of mammalian cells, resulting in adverse effects, because of high residue levels. To test the possibility, we examined the effects of captan on rat thymic lymphocytes using flow-cytometry with appropriate fluorescent probes. Treatment with 10 and 30 μM captan induced apoptotic and necrotic cell death. Before cell death occurred, captan elevated the intracellular concentrations of Ca²⁺ and Zn²⁺ and decreased the concentration of cellular thiol compounds. These captan-induced phenomena are shown to cause cell death and are similar to those caused by oxidative stress. Captan also elevated the cytotoxicity of hydrogen peroxide. Results indicate that 10 and 30 μM captan cause cytotoxic effects on mammalian cells. Despite no report on the significant environmental toxicity hazard of captan in humans, it may exhibit adverse effects, described above, on wild organisms.

Conflicting actions of 4-vinylcatechol in rat lymphocytes under oxidative stress induced by hydrogen peroxide

4-Vinylcatechol (4VC) has been identified as an aroma compound in roasted foods, especially coffee. It is also a component in traditional herbal medicines. This compound may be subconsciously ingested through foods and herbs. Recent experimental evidence has shown that 4VC possesses an antioxidative action. However, the antioxidative action of 4VC at cellular levels is not well characterized. The effects of 4VC (0.1-100 µM) were examined on rat thymic lymphocytes without and with oxidative stress induced by 300 µM hydrogen peroxide (H₂O₂). Cell treatment with 100 µM 4VC alone for 4 h significantly increased the population of dead cells. Thus, 4VC at 100 µM or above elicits cytotoxicity. However, 4VC at sublethal concentrations (1-10 µM) significantly attenuated the H₂O₂-induced increase in cell lethality in a concentration-dependent manner. While application of 10 µM 4VC slowed the process of cell death induced by H₂O₂, 4VC did not antagonize the H₂O₂-induced reduction of cellular nonprotein thiols. Although 4VC at 10 µM did not affect intracellular Ca²⁺ and Zn²⁺ levels, the agent potentiated the H₂O₂-induced increases in these levels. These actions of 10 µM 4VC are adverse to the cells under the oxidative stress. However, 10 µM 4VC partly attenuated the cell death induced by 100 nM A23187, a calcium ionophore. There are conflicting actions of 4VC at 1-100 µM on the cells under oxidative stress although the agent is used for an antioxidant. Thus, caution is required when using 4VC as a therapeutic agent.

Search for Boosted Dark Matter Interacting with Electrons in Super-Kamiokande

A search for boosted dark matter using 161.9 kt yr of Super-Kamiokande IV data is presented. We search for an excess of elastically scattered electrons above the atmospheric neutrino background, with a visible energy between 100 MeV and 1 TeV, pointing back to the Galactic center or the Sun. No such excess is observed. Limits on boosted dark matter event rates in multiple angular cones around the Galactic center and Sun are calculated. Limits are also calculated for a baseline model of boosted dark matter produced from cold dark matter annihilation or decay. This is the first experimental search for boosted dark matter from the Galactic center or the Sun interacting in a terrestrial detector.