Acute exacerbation of immunoglobulin A nephropathy complicated by alveolar hemorrhage after coronavirus disease 2019 vaccination: A case report

RATIONALE

Reports have suggested a relationship between coronavirus disease 2019 (COVID-19) vaccination and new-onset or recurring renal diseases, of which immunoglobulin A (IgA) nephropathy is a representative disease. Alveolar hemorrhage in patients with IgA nephropathy is rare but reportedly has a high mortality and morbidity. To our knowledge, there have been no reports regarding the development of IgA nephropathy with alveolar hemorrhage following COVID-19 vaccination.

PATIENTS CONCERN

A 23-year-old Japanese man presented with hemoptysis and peripheral edema a few days after receiving a second dose of a COVID-19 mRNA vaccine. Severe renal failure and alveolar hemorrhage were noted thereafter, and renal biopsy showed crescentic glomerulonephritis with mesangial proliferation accompanied by mesangial electron-dense deposits containing IgA. Renal biopsy tissue also showed chronic histological changes suggestive of acute exacerbation of preexisting IgA nephropathy.

DIAGNOSIS

The diagnosis of IgA nephropathy complicated by alveolar hemorrhage was made.

INTERVENTIONS AND OUTCOMES

Renal function did not recover despite treatment with high-dose steroids; the patient was maintained on hemodialysis and eventually underwent successful renal transplantation.

LESSONS

The present case suggested that although extremely rare, severe renal failure requiring renal replacement therapy could occur in patients with IgA nephropathy after COVID-19 vaccination. Future accumulation of similar cases is needed to predict the risk of renal injury following vaccination.

Histological transition from minimal change disease to THSD7A-associated membranous nephropathy in a patient receiving long-term steroid treatment: A case report

RATIONALE

A predominant Th2 immune response is suggested in the pathogenesis of both minimal change disease (MCD) and membranous nephropathy (MN); however, consecutive development of the 2 diseases in a patient is extremely rare.

PATIENT CONCERN

A Japanese man, who developed nephrotic syndrome in his 50s and was diagnosed with MCD by renal biopsy, experienced a relapse of proteinuria approximately 3 years later during long-term steroid treatment. Since the proteinuria was resistant to increase in steroid dosage, repeat renal biopsy was performed, which revealed a small amount of glomerular subepithelial immune deposits containing immunoglobulin (Ig)G (dominantly IgG4). Immunostaining for thrombospondin-type-1-domain-containing-7A (THSD7A) was positive on the glomerular capillary walls, whereas that for other causative antigens of MN, such as phospholipase A2 receptor or neural epidermal growth factor-like 1 protein, was negative. Detailed examination found no associated condition, including malignancies and allergic diseases.

DIAGNOSIS

The diagnosis of THSD7A-associated idiopathic MN was made.

INTERVENTIONS AND OUTCOMES

He received further increased dose of steroids. Thereafter he maintained clinical improvement because his urinary protein level was decreased.

LESSONS

The present case suggested that histological transition from MCD to MN is possible and repeat biopsy would be crucial for accurate diagnosis.

Proliferative glomerulonephritis with monoclonal immunoglobulin G3 lambda deposits accompanied by glomerular positive staining for nephritis-associated plasmin receptor and related plasmin activity: A report of two cases

Proliferative glomerulonephritis with monoclonal immunoglobulin (Ig) G deposits (PGNMID) is a relatively uncommon entity of monoclonal gammopathy of renal significance, and its detailed pathogenesis is not well understood. We, herein, report two cases of patients with PGNMID; their renal biopsy showed glomerular histological features of membranoproliferative glomerulonephritis pattern with endocapillary proliferation accompanied by non-organized granular electron-dense deposits that consisted of monoclonal IgG3-lambda. Neither symptomatic episodes of preceding infection nor infection foci were found in both patients; however, glomerular positive staining for nephritis-associated plasmin receptor (NAPlr) and related plasmin activity were observed. Although NAPlr was originally considered as a candidate nephritogenic protein for post-streptococcal acute glomerulonephritis, its positive staining and related plasmin activity have been observed in glomeruli of various cases with bacterial infection-related glomerulonephritis and is considered to be a general histological biomarker of infection-related glomerulonephritis. The present cases suggest that evaluation of immunoreactivity for NAPlr and related plasmin activity in glomeruli provides an important clue regarding the infection-related pathogenesis of PGNMID.

Association between Dairy Product intake and Risk of Osteoporotic Fractures in Postmenopausal Japanese Women: Secondary Analysis of 15-Year Follow-Up data from the Japanese Population-Based Osteoporosis (JPOS) Cohort Study

OBJECTIVES

Few prospective cohort studies have evaluated the relationship between dairy product intake frequency and risk of osteoporotic fractures in Asians. This study aimed to investigate the association between habitual dairy product intake and risk of osteoporotic fractures.

DESIGN

Secondary analysis of prospective cohort study.

SETTING

Five municipalities of Japan.

PARTICIPANTS

This study included 1,429 postmenopausal Japanese women (age ≥45 years at baseline).

MEASUREMENTS

Baseline milk-intake frequency was obtained using nurse-administered questionnaires. Intakes of yogurt and cheese, and estimated calcium intake, were assessed using a validated food frequency questionnaire. Osteoporotic fracture was defined as a clinical fracture diagnosed using radiography. Hazard ratios (HRs) with 95% confidence intervals (CIs) were estimated using Cox proportional hazards models.

RESULTS

Over a median follow-up period of 15.1 years (interquartile range [IQR], 10.1-15.4 years; total, 18,118 person-years), 172 women sustained at least one osteoporotic fracture. The proportions of participants with milk intakes <1, 1, and ≥2 cups/d were 34.4%, 48.0%, and 17.6%, respectively. After adjustment for age, frequency of yogurt intake, frequency of cheese intake, body mass index, history of osteoporotic fractures, and frequency of natto intake, the HRs compared with that for milk intake <1 cup/d were 0.71 (95% CI: 0.51-0.98) and 0.57 (95% CI: 0.35-0.92) for 1 cup/d and ≥2 cups/d, respectively. After adjustment for bone mineral density, HR significance for milk intakes ≥2 cups/d remained significant. Yogurt and cheese intakes were not related to the risk of osteoporotic fractures.

CONCLUSION

High habitual milk intake, but not a habitual yogurt or cheese intake is associated with a decreased risk of osteoporotic fractures, independent of bone mineral density, in postmenopausal Japanese women.

Study of beamlets extracted from a multi-aperture and five-stage acceleration system

A beam optics study using the ITER-relevant high intense negative ion beams, such as 1 MeV, 200 A/m², has been performed experimentally and analytically using a multi-aperture and five-stage accelerator. Initially, multi-beamlets generated from this accelerator were deflected in various directions due to the magnetic field and space charge repulsion between beams and showed various divergences. These had limited the pulse length and the beam energy. Compensation methods of the beamlet deflections have worked effectively and contributed to achieving the ITER requirement, the divergence angle of <7 mrad, and the deflection angle of <1 mrad for 1 MeV beam. The beam pulse has been gradually extended from 1 to 100 s and is now going to a longer pulse based on these results. One of the remaining issues is to understand and suppress peripheral components of the beam, namely, the halo, and to reduce the local heat loads observed around the aperture edge. This halo component has been successfully distinguished from the beam core by using a newly developed beam emittance measurement system for high intense beams. By combining this measured beam emittance and the beam simulation, it was clarified for the first time that the halo components are generated in an area of 1 mm width from the aperture edge.

Thrombotic microangiopathy with transiently positive direct Coombs test in an adult with poststreptococcal acute glomerulonephritis: a case report

Background

To date, a few case reports have described the association between poststreptococcal acute glomerulonephritis (PSAGN) and hemolytic anemia/thrombocytopenia, both with or without a pathology similar to that of thrombotic microangiopathy (TMA). However, the detailed mechanism leading to the complication of TMA in PSAGN patients remains to be clarified. In contrast, infection with neuraminidase-producing Streptococcus pneumoniae is a well-known cause of TMA, and it has been reported that transient positivity of the direct Coombs test is observed in up to 90% of such patients.

Case presentation

A 44-year-old man was hospitalized for acute nephritic syndrome 3 weeks after developing pharyngitis. PSAGN was suspected owing to a low complement C3, increased antistreptolysin-O and serum creatinine (5.46 mg/dL), and hematuria/proteinuria. The throat antigen test for group A Streptococcus was positive. He developed hemolytic anemia with thrombocytopenia from hospital day 9. TMA was suspected owing to minimal coagulation abnormalities. ADAMTS-13 activity was normal, whereas the direct Coombs test was transiently positive. Renal biopsy demonstrated glomerular endocapillary proliferation without crescents, but with severe tubulitis and peritubular capillaritis on light microscopy. Immunofluorescence demonstrated C3 deposition along the glomerular capillary walls, and many subepithelial humps were observed on electron microscopy. The deposition of nephritis-associated plasmin receptor (NAPlr), a nephritogenic protein of Streptococcus pyogenes, was observed only in glomeruli. Thus, the histological diagnosis was typical PSAGN, but with atypical severe tubulointerstitial lesions. A positive direct Coombs test is often observed in pneumococcal TMA patients, which is attributed to the exposure of Thomsen–Friedenreich (T) antigen by neuraminidase. As Streptococcus pyogenes is one of the neuraminidase-producing bacteria other than Streptococcus pneumoniae, T-antigen exposure was analyzed in the renal tissue of this patient using labelled peanut lectin as a probe, which has strong and specific binding affinity for T-antigen. Exposure of T-antigen was found on tubular epithelial cells and small vessels in the tubulointerstitial area, but not in the glomeruli of this patient.

Conclusion

These findings suggest that 2 pathogenic proteins of Streptococcus pyogenes, i.e., NAPlr and neuraminidase, induced glomerular lesions of PSAGN and tubulointerstitial inflammation with TMA, respectively, resulting in severe acute kidney injury in this patient.

The impact of intraoperative pericardial three-dimensional echocardiography for the atrioventricular valve repair in the patient with congenital heart disease

Background

Atrioventricular valve (AVV) regurgitation enormously affected the survival outcome of the patients with congenital heart disease (CHD). However, the image quality by use of transthoracic echocardiography has not reached a level that is sufficient, and also, three-dimensional echocardiography, which is useful to clarify complex AVV anatomy, cannot be applied for the patients less than 15kg, to guide for the AVV repair in pediatric patients. We try to show surgeons more precise three-dimensional images about an AVV by using intraoperative pericardial three-dimensional echocardiography (IP3DE) and improve the surgical outcome.

Purpose

To determine the efficacy of IP3DE by assessing the surgical outcome of an AVV repair and re-intervention rate.

Method

Eighty-five patient with CHD who underwent atrioventricular repair with significant regurgitation (Grade 2–4+) before operation were divided into two groups imaged IP3DE or not, in our hospital from 1993 to 2020. We assessed the surgical outcome and re-intervention rate between two arms and re-evaluate AVV images before surgery compared to the IP3DE.

Result

IP3DE was performed in forty-six patients (IP3DE group) and thirty-nine patients were not (control group). Median age at AVV repair was 3.0/2.8 years, respectively. The AVV was tricuspid (n=25), mitral (n=41), or common (n=19). The IP3DE group had a significantly higher improvement in regurgitation of AVV (IP3DE: Grade 3.2±0.3 → 1.7±0.3 vs Control: Grade 2.8±0.3 → 1.8±0.3, p&lt;0.05). Fifty-nine percent of the IP3DE group was successful outcome (Grade&lt;1+ after repair). There was no significant difference in the rate of re-intervention after surgery between two groups. In multivariate analysis, using IP3DE contributed to successful outcome for AVV repair (OR: 4.66, 95% CI: 1.46–14.8, p&lt;0.01). The different and/or additional anatomical AVV findings were obtained in sixty-one percent of patients by the IP3DE.

Conclusion

IP3DE contributes to successful outcome for AVV repair by obtaining further information on complicated AVV anatomy in congenital heart disease. IP3DE also enables both cardiovascular surgeons and cardiologists to share the accurate and detail “surgeon's view” in the operating room for planning of AVV repair.

Funding Acknowledgement

Type of funding sources: None.

Membranous Nephropathy With Monoclonal IgM Lambda Deposits in a Patient With IgM Monoclonal Gammopathy: A Case Report

We report a case of membranous nephropathy with monoclonal immunoglobulin (Ig)M lambda deposits in a patient with IgM monoclonal gammopathy, in whom histological changes were observed on repeat renal biopsy. A 72-year-old Japanese woman was referred to our hospital because of massive proteinuria. A prominent increase in monoclonal IgM lambda level was identified, and she was diagnosed as having IgM monoclonal gammopathy of undetermined significance. Renal biopsy showed glomerular subepithelial electron-dense deposits that were found to be granular deposits of IgM lambda but not kappa or IgG by immunofluorescence staining, resulting in a diagnosis of membranous nephropathy with monoclonal IgM deposits. The second biopsy, which was performed 2 years later because of exacerbation of her nephrotic syndrome, demonstrated less immunofluorescence staining of IgM, and dominant IgG2 deposition without light chain restriction. Interestingly, immunostaining for thrombospondin-type-1-domain-containing-7A was positive in both renal biopsy tissues, although the second biopsy showed clearly stronger immunoreactivity. The effect of steroid therapy was limited; however, rituximab treatment improved both the hematological and renal abnormalities. Solitary deposition of IgM in membranous nephropathy is a quite rare condition. To our knowledge, this is the first case of monoclonal gammopathy of renal significance presenting as membranous nephropathy with monoclonal IgM deposits, in which chronological immunohistochemical changes were observed and rituximab therapy was effective.

Complete remission of DnaJ homolog subfamily B member 9-positive fibrillary glomerulonephritis following steroid monotherapy in an elderly Japanese woman

A 74-year-old Japanese woman was referred to our department because of anasarca and massive proteinuria. She was clinically diagnosed with nephrotic syndrome, and renal biopsy showed membranoproliferative glomerulonephritis accompanied by marked glomerular infiltration with macrophages and full-house immunofluorescence glomerular deposition. Furthermore, randomly arranged nonbranching fibrils, approximately 12 nm in diameter, were found by electron microscopy, and immunostaining for DnaJ homolog subfamily B member 9 (DNAJB9), a recently identified diagnostic biomarker of fibrillary glomerulonephritis (FGN), showed positive result, thereby confirming the diagnosis of FGN. Steroid treatment was initiated, and she obtained complete remission of nephrotic syndrome and has maintained it. FGN is an uncommon form of glomerular disease, and reported cases of DNAJB9-positive FGN among Asians, particularly among Japanese population, are rare. There have been no established therapeutic regimens and its renal prognosis is generally unfavorable. The present case suggests that some patients with FGN can achieve favorable clinical outcomes through steroid monotherapy.

Analysis of the cesium distribution in the JT-60SA negative ion sources for steady long-pulse operation

To realize stable negative ion beams for 100 s required in the neutral beam injector of JT-60SA, a physical model to control cesium (Cs) distribution inside the negative ion source has been developed in order to maintain the stable negative ion production at the plasma grid (PG) surface with Cs. In this work, to quantitatively evaluate Cs coverage on the PG, a three-dimensional Cs transportation code was introduced to consider the spatial Cs distribution in the source. The spatial temperature distribution of the chamber wall was also introduced in this model. As a result, the reasonable variation of the Cs coverage for 100 s was obtained, compared to that in the initial model. Based on the modified model, the operational temperature of the chamber wall was proposed to be less than 60 °C to suppress the desorption of Cs in the chamber wall and to sustain the stable negative ion production. In addition, it was also suggested that a slightly higher wall temperature before the operation leads to a decrease in the amount of Cs stored at the chamber wall, resulting in suppression of Cs consumption in the ion source.

Achievement of high power and long pulse negative ion beam acceleration for JT-60SA NBI

Long pulse acceleration of hydrogen negative ion beams with the power density over 70 MW/m² and the pulse length over 100 s has been demonstrated for the first time by using a multi-aperture 3-stage accelerator. Such long pulse acceleration was achieved by integrating the design of beam optics and voltage holding capability to meet the requirements of JT-60SA. By using the newly designed accelerator for JT-60SA, voltage holding at 500 kV with beam acceleration was stably sustained even after 5 g of cesium was seeded, and heat load on each acceleration grid was reduced below the allowable level for long pulse, less than 5% of total acceleration power. As a result, 500 keV, 154 A/m² for 118 s beam acceleration was achieved, which satisfies the requirement of the negative ion source for JT-60SA. This pulse length of such high-power density beams is longest in the world. In addition, the result contributes to the long pulse acceleration of multi-stage electrostatic accelerators, such as 1 MeV negative ion accelerator for ITER.

Decreased Perfusion in Myocardial Region of Normal Donor Artery Secondary to Collateral Development

Thirty-one patients suffering from single vessel exertional angina with collaterals (Group A) were evaluated by stress 201T1 myocardial emission CT (T1-SPECT) with 16 controls of severely stenotic single vessel exertional angina without collaterals (Group B). Group A included 21 patients (68%) who showed an extensive perfusion defect in double artery myocardial regions, including the normal donor artery myocardial region (DMR). However, there were no such cases in Group B, giving a significant difference between these 2 groups (p < 0.001). Four patients in Group A, having a perfusion defect both in DMR and in the collateral dependent myocardial region (CMR) underwent a successful percutaneous transluminal coronary angioplasty (PTCA) with disappearance of collaterals. T1-SPECT findings after PTCA showed no perfusion defect either in CMR or in DMR. This has been explained on the basis that the coronary collaterals stole blood and produced perfusion defect in DMR.

Development of the negative ion beams relevant to ITER and JT-60SA at Japan Atomic Energy Agency

In order to realize negative ion sources and accelerators to be applicable to International Thermonuclear Experimental Reactor and JT-60 Super Advanced, a large cesium (Cs)-seeded negative ion source and a multi-aperture and multi-stage electric acceleration have been developed at Japan Atomic Energy Agency (JAEA). Long pulse production and acceleration of the negative ion beams have been independently carried out. The long pulse production of the high current beams has achieved 100 s at the beam current of 15 A by modifying the JT-60 negative ion source. The pulse duration time is increased three times longer than that before the modification. As for the acceleration, a pulse duration time has been also extended two orders of magnitudes from 0.4 s to 60 s. The developments of the negative ion source and acceleration at JAEA are well in progress towards the realization of the negative ion sources and accelerators for fusion applications.

Analysis of the beam halo in negative ion sources by using 3D3V PIC code

The physical mechanism of the formation of the negative ion beam halo and the heat loads of the multi-stage acceleration grids are investigated with the 3D PIC (particle in cell) simulation. The following physical mechanism of the beam halo formation is verified: The beam core and the halo consist of the negative ions extracted from the center and the periphery of the meniscus, respectively. This difference of negative ion extraction location results in a geometrical aberration. Furthermore, it is shown that the heat loads on the first acceleration grid and the second acceleration grid are quantitatively improved compared with those for the 2D PIC simulation result.

Time evolution of negative ion profile in a large cesiated negative ion source applicable to fusion reactors

To understand the physics of the cesium (Cs) recycling in the large Cs-seeded negative ion sources relevant to ITER and JT-60SA with ion extraction area of 45-60 cm × 110-120 cm, the time evolution of the negative ion profile was precisely measured in JT-60SA where the ion extraction area is longitudinally segmented into 5. The Cs was seeded from the oven at 180 °C to the ion source. After 1 g of Cs input, surface production of the negative ions appeared only in the central segment where a Cs nozzle was located. Up to 2 g of Cs, the negative ion profile was longitudinally expanded over full ion extraction area. The measured time evolution of the negative ion profile has the similar tendency of distribution of the Cs atoms that is calculated. From the results, it is suggested that Cs atom distribution is correlated with the formation of the negative ion profile.

Development of design technique for vacuum insulation in large size multi-aperture multi-grid accelerator for nuclear fusion

Design techniques for the vacuum insulation have been developed in order to realize a reliable voltage holding capability of multi-aperture multi-grid (MAMuG) accelerators for fusion application. In this method, the nested multi-stage configuration of the MAMuG accelerator can be uniquely designed to satisfy the target voltage within given boundary conditions. The evaluation of the voltage holding capabilities of each acceleration stages was based on the previous experimental results about the area effect and the multi-aperture effect. Since the multi-grid effect was found to be the extension of the area effect by the total facing area this time, the total voltage holding capability of the multi-stage can be estimated from that per single stage by assuming the stage with the highest electric field, the total facing area, and the total apertures. By applying these consideration, the analysis on the 3-stage MAMuG accelerator for JT-60SA agreed well with the past gap-scan experiments with an accuracy of less than 10% variation, which demonstrated the high reliability to design MAMuG accelerators and also multi-stage high voltage bushings.

Tumor necrosis factor-alpha gene promoter methylation in Japanese adults with chronic periodontitis and rheumatoid arthritis

BACKGROUND AND OBJECTIVE

Over-expression of tumor necrosis factor-alpha (TNF-α) plays a pathological role in chronic periodontitis (CP) and rheumatoid arthritis (RA), which might be regulated by the epigenetic mechanism. The aim of the present study was to evaluate whether there is a unique methylation profile of the TNF-α gene promoter in blood cells of individuals with CP and RA.

MATERIAL AND METHODS

The study participants consisted of 30 Japanese adults with RA (RA group), 30 race-matched adults with CP only (CP group) and 30 race-matched healthy controls (H group). Genomic DNA isolated from peripheral blood was modified by sodium bisulfite and analyzed, by direct sequencing, to investigate DNA methylation of the TNF-α gene promoter region. The level of TNF-α produced in mononuclear cells stimulated with Porphyromonas gingivalis lipopolysaccharide was determined using ELISA.

RESULTS

Twelve cytosine-guanine dinucleotide (CpG) motifs were identified in the TNF-α promoter fragment from -343 to +57 bp. The CP group showed a significantly higher methylation rate and frequency at -72 bp than the H group (p < 0.01). The RA group exhibited significantly higher methylation rates at seven CpG motifs (-302, -163, -119, -72, -49, -38 and +10 bp), and significantly higher methylation frequencies at six CpG motifs (-163, -119, -72, -49, -38 and +10 bp), than the H group (p < 0.01 for all comparisons). The levels of TNF-α produced were significantly different between individuals with and without methylation at -163 bp (p = 0.03).

CONCLUSION

These results suggest that the hypermethylated status of CpG motifs in the TNF-α gene promoter in blood cells may be unique to Japanese adults with CP and RA.

Roles of extracellular Ca(2+) in the occurrence of full-type hyperactivation in boar ejaculated spermatozoa pre-incubated to induce the cAMP-triggered events

There are species differences in the regulatory system for sperm capacitation and subsequent hyperactivation between livestock and laboratory animals. In livestock spermatozoa, it is poorly understood when and how extracellular Ca(2+) is necessary for hyperactivation, although it has been demonstrated that the [Ca(2+) ]i increase is indispensable to occurrence of hyperactivation. In this study, we examined necessity of extracellular Ca(2+) for the initiation and maintenance of hyperactivation and then sought possible target molecule of Ca(2+) that was involved in hyperactivation of boar spermatozoa. Boar ejaculated spermatozoa were pre-incubated with a cell-permeable cyclic adenosine monophosphate (cAMP) analog 'cBiMPS' and without CaCl2 to induce the cAMP-triggered events including capacitation-associated changes. Subsequently, they were incubated with CaCl2 to induce hyperactivation and then used for motility assessment. Many of the spermatozoa after the incubation exhibited full-type hyperactivation which was characterized by high-amplitude and extremely asymmetrical beating of whole middle piece and principal piece. The initiation of full-type hyperactivation required the millimolar concentration of CaCl2 in the medium. However, CaCl2 of the medium was less necessary for maintenance than initiation of full-type hyperactivation, as hyperactivated spermatozoa were barely affected by the incubation with the Ca(2+) -chelating reagent. On the other hand, the pre-treatment with the inhibitor for Ca(2+) -dependent protease 'calpain 1 and 2' clearly suppressed the occurrence of CaCl2 -induced hyperactivation without influences on the percentages of motile spermatozoa. Western blotting and indirect immunofluorescence showed distribution of calpain 2 in the middle and principal pieces in which full-type hyperactivated spermatozoa exhibited extremely asymmetrical beating. On the basis of these results, we conclude that the millimolar concentration of extracellular Ca(2+) is necessary for the initiation, but not for the maintenance of full-type hyperactivation in boar spermatozoa that beforehand undergo the cAMP-triggered events including capacitation-associated changes. Moreover, we suggest possible involvement of calpain 2 in the intracellular Ca(2+) signal transduction leading to full-type hyperactivation.

Long-pulse beam acceleration of MeV-class H(-) ion beams for ITER NB accelerator

In order to realize neutral beam systems in International Thermonuclear Experimental Reactor whose target is to produce a 1 MeV, 200 A/m(2) during 3600 s D(-) ion beam, the electrostatic five-stages negative ion accelerator so-called "MeV accelerator" has been developed at Japan Atomic Energy Agency. To extend pulse length, heat load of the acceleration grids was reduced by controlling the ion beam trajectory. Namely, the beam deflection due to the residual magnetic field of filter magnet was suppressed with the newly developed extractor with a 0.5 mm off-set aperture displacement. The new extractor improved the deflection angle from 6 mrad to 1 mrad, resulting in the reduction of direct interception of negative ions from 23% to 15% of the total acceleration power, respectively. As a result, the pulse length of 130 A/m(2), 881 keV H(-) ion beam has been successfully extended from a previous value of 0.4 s to 8.7 s. This is the first long pulse negative ion beam acceleration over 100 MW/m(2).

Development of negative ion extractor in the high-power and long-pulse negative ion source for fusion application

High power and long-pulse negative ion extractor, which is composed of the plasma grid (PG) and the extraction grid (EXG), is newly developed toward the neutral beam injector for heating and current drive of future fusion machines such as ITER, JT-60 Super Advanced and DEMO reactor. The PG is designed to enhance surface production of negative ions efficiently by applying the chamfered aperture. The efficiency of the negative ion production for the discharge power increased by a factor of 1.3 against that of the conventional PG. The EXG is also designed with the thermal analysis to upgrade the cooling capability for the long pulse operation of >1000 s required in ITER. Though the magnetic field for electron suppression is reduced to 0.75 of that in the conventional EXG due to this upgrade, it was experimentally confirmed that the extracted electron current can be suppressed to the allowable level for the long pulse operation. These results show that newly developed extractor has the high potential for the long pulse extraction of the negative ions.

100 s extraction of negative ion beams by using actively temperature-controlled plasma grid

Long pulse beam extraction with a current density of 120 A/m(2) for 100 s has been achieved with a newly developed plasma grid (PG) for the JT-60SA negative ion source which is designed to produce high power and long pulse beams with a negative ion current of 130 A/m(2) (22 A) and a pulse length of 100 s. The PG temperature is regulated by fluorinated fluids in order to keep the high PG temperature for the cesium-seeded negative ion production. The time constant for temperature controllability of the PG was measured to be below 10 s, which was mainly determined by the heat transfer coefficient of the fluorinated fluid. The measured decay time of the negative ion current extracted from the actively temperature-controlled PG was 430 s which was sufficient for the JT-60SA requirement, and much longer than that by inertial-cooling PG of 60 s. Obtained results of the long pulse capability are utilized to design the full size PG for the JT-60SA negative ion source.

Aggravation of inflammatory bowel diseases by oral streptococci

OBJECTIVES

Streptococcus mutans can aggravate colitis in mice. We evaluated the virulence of colitis using type strains as well as blood isolates of several oral streptococcal species.

MATERIALS AND METHODS

We investigated the susceptibility of blood isolates of several oral streptococci to phagocytosis, adhesion to and invasion of hepatic cells and interferon-γ secretion. A mouse model of dextran sodium sulphate-induced colitis was used to evaluate bacterial aggravation of colitis. In addition, interferon-γ antibody was administered to mice with prominent aggravation of colitis.

RESULTS

In vitro analyses showed that Streptococcus sanguinis ATCC 10556 was a possible virulent strain among type strains of several oral streptococci, and that analysis of blood isolates of S. sanguinis TW289 revealed a potential virulent strain. Intravenous administration of ATCC 10556 and TW289 caused prominent aggravation of dextran sodium sulphate-induced colitis, and histopathological examinations showed that interferon-γ secretion due to infection of hepatic cells caused colitis aggravation. Administration of interferon-γ antibody suppressed TW289-induced colitis.

CONCLUSION

These results suggest that some virulent oral streptococcal strains are associated with the aggravation of colitis induced by enhanced secretion of interferon-γ when they invade the bloodstream.

Resolution of clinical symptoms after reopening of an occluded inferior petrosal sinus in a patient with a cavernous sinus dural arteriovenous fistula. A case report

We describe a rare case with a cavernous sinus (CS) dural arteriovenous fistula (DAVF) in which the clinical symptoms disappeared after the patient underwent reopening of an occluded inferior petrosal sinus (IPS). A 66-year-old woman presented with increased intraocular pressure, chemosis, and proptosis on the left side. Angiography demonstrated a left CS DAVF supplied by the dural branches of bilateral internal carotid arteries. The shunt flow was directed to the superior and inferior ophthalmic veins, while the bilateral IPSs were not opacified. Accordingly, a transvenous embolization of the fistula was attempted. Although the microcatheter was navigated to the cavernous sinus through the occluded left IPS, obliteration of the fistula was unsuccessful because of the failure of superselective catheterization at the fistulous point. However, the final image demonstrated the development of an antegrade shunt flow through the left IPS to the internal jugular vein and disappearance of the retrograde reflux to the superior and inferior ophthalmic veins. The patient's clinical symptoms immediately resolved after the operation, and the symptoms have not recurred during a one-year follow-up period. Inappropriate transvenous embolization of CS DAVFs can result in vascular complications arising from the unintentional redistribution of shunt flow. The present case illustrates that the disappearance of retrograde shunt flow to the ophthalmic veins after reopening of the occluded IPS may be sufficient if a superselective approach fails or is anticipated to result only in an incomplete embolization of the fistulous point.

Presence of store-operated Ca2+ entry in C57BL/6J mouse ventricular myocytes and its suppression by sevoflurane

BACKGROUND

Store-operated Ca(2+) entry (SOCE) has been implicated in various pathological conditions of the heart including ischaemia/reperfusion and ventricular hypertrophy. This study investigated the effects of sevoflurane on SOCE.

METHODS

Fluorescence imaging was performed on fluo-3- and mag-fluo-4-loaded mouse ventricular myocytes to measure the cytosolic and intraluminal sarcoplasmic reticulum (SR) Ca(2+) levels, respectively, using a confocal laser scanning microscope. Whole-cell membrane currents were recorded using the patch-clamp technique. Ventricular myocytes were exposed to thapsigargin and angiotensin II to deplete SR Ca(2+) stores and thereby activate SOCE.

RESULTS

The combined application of thapsigargin and angiotensin II to the Ca(2+)-free medium evoked a significant decrease in the SR Ca(2+) levels, which was followed by the elevation of cytosolic Ca(2+) and the development of cellular hypercontracture upon subsequent addition of extracellular Ca(2+). This cytosolic Ca(2+) elevation was inhibited by 2-aminoethoxydiphenyl borate but not by verapamil and KB-R7943, which indicates that SOCE was present in mouse ventricular myocytes. Sevoflurane concentration-dependently inhibited the SOCE-mediated Ca(2+) overload (IC(50) of 137 μM, which corresponds to 0.96%) with a significant reduction occurring at concentrations of ≥2%. Patch-clamp experiments revealed that the SOCE current was also concentration-dependently blocked by sevoflurane (IC(50) of 144 μM, which corresponds to 1.0%).

CONCLUSIONS

Sevoflurane at concentrations of ≥2% significantly inhibits the SOCE activity and prevents the resultant cellular Ca(2+) overload that leads to hypercontracture in ventricular myocytes. This inhibitory action may be involved in the cardioprotective effect of sevoflurane against Ca(2+) overload-mediated injury.

Vacuum insulation of the high energy negative ion source for fusion application

Vacuum insulation on a large size negative ion accelerator with multiple extraction apertures and acceleration grids for fusion application was experimentally examined and designed. In the experiment, vacuum insulation characteristics were investigated in the JT-60 negative ion source with >1000 apertures on the grid with the surface area of ∼2 m(2). The sustainable voltages varied with a square root of the gap lengths between the grids, and decreased with number of the apertures and with the surface area of the grids. Based on the obtained results, the JT-60SA (super advanced) negative ion source is designed to produce 22 A, 500 keV D(-) ion beams for 100 s.

Voltage holding study of 1 MeV accelerator for ITER neutral beam injector

Voltage holding test on MeV accelerator indicated that sustainable voltage was a half of that of ideal quasi-Rogowski electrode. It was suggested that the emission of the clumps is enhanced by a local electric field concentration, which leads to discharge initiation at lower voltage. To reduce the electric field concentration in the MeV accelerator, gaps between the grid supports were expanded and curvature radii at the support corners were increased. After the modifications, the accelerator succeeded in sustaining -1 MV in vacuum without beam acceleration. However, the beam energy was still limited at a level of 900 keV with a beam current density of 150 A∕m(2) (346 mA) where the 3 × 5 apertures were used. Measurement of the beam profile revealed that deflection of the H(-) ions was large and a part of the H(-) ions was intercepted at the acceleration grid. This causes high heat load on the grids and the breakdowns during beam acceleration. To suppress the direct interception, new grid system was designed with proper aperture displacement based on a 3D beam trajectory analysis. As the result, the beam deflection was compensated and the voltage holding during the beam acceleration was improved. Beam parameter of the MeV accelerator was increased to 980 keV, 185 A∕m(2) (427 mA), which is close to the requirement of ITER accelerator (1 MeV, 200 A∕m(2)).

Characterization of aortic aneurysms in cardiovascular disease patients harboring Porphyromonas gingivalis

OBJECTIVE

Porphyromonas gingivalis was recently shown to cause intimal hyperplasia in a mouse model by a novel cholesterol-independent mechanism, suggesting to be a pathogen-specific feature of cardiovascular diseases. The aim of this study was to characterize the clinical and histopathological features of aortic aneurysms in cardiovascular disease patients harboring oral P. gingivalis.

SUBJECT AND METHODS

Aortic aneurysm specimens were collected from 76 Japanese patients who underwent surgery, of whom dental plaque specimens were also collected from 31 patients. Bacterial DNA was extracted from each specimen to detect P. gingivalis by polymerase chain reaction. Histopathological analyses of the aortic aneurysm specimens, including immunohistochemical staining for embryonic myosin heavy chain isoform (SMemb) and S100 calcium-binding protein A9 (S100A9), were also performed.

RESULTS

The number of aneurysms occurring in the distal aorta was significantly higher in subjects positive for P. gingivalis in dental plaque compared with those who were negative. The expressions of S100A9 and SMemb were also significantly greater in the subjects positive for P. gingivalis in dental plaque. On the other hand, there were no significant differences in adipocellular accumulation between the groups.

CONCLUSIONS

These results suggest that aortic aneurysms in patients harboring oral P. gingivalis have greater expression of S100A9 and proliferative smooth muscle cells, which was different from the present patients without oral P. gingivalis.

Observation of a complex multistage transition in the JT-60U H-mode edge

A complex multistage transition of the edge radial electric field is observed in JT-60U H-mode phase without edge localized mode. An interesting feature is that the poloidal rotation velocity of the carbon impurity ions changes in the later H-phase without a comparable change in the main ion pressure gradient, indicating a change in the parallel momentum (and particle) balance channel.

Zeeman polarimetry measurement for edge current density determination using Li-beam probe on JT-60U

Zeeman polarimetry system using Li-beam probe has been developed for the edge current density measurement in the JT-60U tokamak, which measures the polarization angle alpha (related to the pitch angle of the magnetic field) by means of photoelastic modulators, etalons, and phase sensitive detection using digital lock-in amplifiers with the accuracy in the alpha of Delta alpha approximately 0.1 degrees. The diagnostic has 20-channel viewing chords covering the plasma peripheral region of normalized minor radius r/a approximately 0.8-1 with a spatial resolution of up to approximately 1 cm. Li-beam injection with beam current of up to approximately 5 mA has been achieved. A new tuning method of the wavelength for the etalon has been demonstrated, scanning the beam acceleration voltage and keeping a beam current constant during a single shot. The peak wavelength of the etalon is adjusted in the direction to both blue- and redshifts by changing the angle of incidence and increasing the temperature, respectively. Time evolution of the edge current density profile has been determined for the current ramp experiment in the Ohmically heated discharges. In addition, the edge current density profile with the local peak of j(ped) approximately 0.15-0.25 MA/m(2) at r/a approximately 0.9 has been identified in the H-mode plasma, which is correlated with large pressure gradient in the pedestal region.

Achievement and improvement of the JT-60U negative ion source for JT-60 Super Advanced (invited)

Developments of the large negative ion source have been progressed in the high-energy, high-power, and long-pulse neutral beam injector for JT-60 Super Advanced. Countermeasures have been studied and tested for critical issues of grid heat load and voltage holding capability. As for the heat load of the acceleration grids, direct interception of D- ions was reduced by adjusting the beamlet steering. As a result, the heat load was reduced below an allowable level for long-pulse injections. As for the voltage holding capability, local electric field was mitigated by tuning gap lengths between large-area acceleration grids in the accelerator. As a result, the voltage holding capability was improved up to the rated value of 500 kV. To investigate the voltage holding capability during beam acceleration, the beam acceleration test is ongoing with new extended gap.

Long pulse H- ion beam acceleration in MeV accelerator

A multiaperture multigrid accelerator called "MeV accelerator" has been developed for neutral beam injection system of international thermonuclear experimental reactor. In the present work, long pulse H(-) ion beam acceleration was performed by the MeV accelerator equipped with new water-cooled grids. At present, the pulse length was extended to 5 s for the beams of 750 keV, 221 mA, and 10 s for the beams of 600 keV, 158 mA. Energy density, defined as products of beam energy (keV), current (mA), and pulse (s) divided by aperture area (m(2)), increased more than one order of magnitude higher compared with original MeV accelerator without water cooling in its grids. At higher energy and current, the grid was melted by beam deflection. Due to this grid melting, breakdowns occurred between the grids, and hence, the pulse length was limited. Beam deflection will be compensated by aperture displacement in next experiment.

Improvement of voltage holding capability in the 500 keV negative ion source for JT-60SA

Voltage holding capability of JT-60 negative ion source that has a large electrostatic negative ion accelerator with 45 cm x 1.1 m acceleration grids was experimentally examined and improved to realize 500 keV, 22 A, and 100 s D- ion beams for JT-60 Super Advanced. The gap lengths in the acceleration stages were extended to reduce electric fields in a gap between the large grids and at the corner of the support flanges from the original 4-5 to 3-4 kV/mm. As a result, the voltage holding capability without beam acceleration has been successfully improved from 400 to 500 kV. The pulse duration to hold 500 kV reached 40 s of the power supply limitation.

Molecular characterization of Streptococcus mutans strains containing the cnm gene encoding a collagen-binding adhesin

OBJECTIVE

Streptococcus mutans, known to be a major pathogen of dental caries, is also considered to cause infective endocarditis. Its 120-kDa Cnm protein binds to type I collagen, which may be a potential virulence factor. In this study, we characterized S. mutans clinical strains focusing on the cnm gene encoding Cnm.

DESIGN

A total of 528 S. mutans strains isolated from Japanese, Finnish, and Thai subjects were investigated. Using molecular techniques, the distribution frequency of cnm-positive strains and location of the inserted cnm were analyzed. Furthermore, isogenic mutant strains were constructed by inactivation of the cnm gene, then their biological properties of collagen-binding and glucan-binding were evaluated. Southern hybridization of the genes encoding glucan-binding proteins was also performed.

RESULTS

The distribution frequency of cnm-positive strains from Thai subjects was 12%, similar to that previously reported for Japanese and Finnish subjects. Furthermore, the location of insertion of cnm was the same in all cnm-positive clinical isolates. As for the cnm-inactivated mutant strains constructed from 28 clinical isolates, their collagen-binding activity was negligible. In addition, glucan-binding activity in the cnm-positive clinical isolates was significantly reduced and corresponded to a lack of gbpA encoding glucan-binding protein A.

CONCLUSIONS

Our results indicate that strains with cnm genes, the most crucial factor for the collagen-binding property of S. mutans, are detectable at similar frequencies over several different geographic locations. In addition, the common properties of these strains are a high level of collagen-binding activity and tendency for a low level of glucan-binding activity.