Regulation of the B cell receptor repertoire and self-reactivity by BAFF

The TNF-family cytokine BAFF (BLyS) promotes B lymphocyte survival and is overexpressed in individuals with systemic lupus erythematosus and Sjögren's Syndrome. BAFF can rescue anergic autoreactive B cells from death, but only when competition from nonautoreactive B cells is lacking. Yet, high BAFF levels promote autoantibody formation in individuals possessing diverse B cells. To better understand how excess BAFF promotes autoimmunity in a polyclonal immune system, Ig L chain usage was analyzed in 3H9 site-directed IgH chain transgenic mice, whose B cells recognize DNA and chromatin when they express certain endogenous L chains. BAFF levels were manipulated in 3H9 mice by introducing transgenes expressing either BAFF or its natural inhibitor ΔBAFF. B cells in BAFF/3H9 mice were elevated in number, used a broad L chain repertoire, including L chains generating high-affinity autoreactivity, and produced abundant autoantibodies. Comparison of spleen and lymph node B cells suggested that highly autoreactive B cells were expanded. By contrast, ΔBAFF/3H9 mice had reduced B cell numbers with a repertoire similar to that of 3H9 mice, but lacking usage of a subset of Vκ genes. The results show that limiting BAFF signaling only slightly selects against higher affinity autoreactive B cells, whereas its overexpression leads to broad tolerance escape and positive selection of autoreactive cells. The results have positive implications for the clinical use of BAFF-depleting therapy.

Peripheral B cell tolerance and function in transgenic mice expressing an IgD superantigen

Transitional B cells turn over rapidly in vivo and are sensitive to apoptosis upon BCR ligation in vitro. However, little direct evidence addresses their tolerance sensitivity in vivo. A key marker used to distinguish these cells is IgD, which, through alternative RNA splicing of H chain transcripts, begins to be coexpressed with IgM at this stage. IgD is also expressed at high levels on naive follicular (B-2) and at lower levels on marginal zone and B-1 B cells. In this study, mice were generated to ubiquitously express a membrane-bound IgD-superantigen. These mice supported virtually no B-2 development, a greatly reduced marginal zone B cell population, but a relatively normal B-1 compartment. B cell development in the spleen abruptly halted at the transitional B cell population 1 to 2 stage, a block that could not be rescued by either Bcl-2 or BAFF overexpression. The developmentally arrested B cells appeared less mature and turned over more rapidly than nontransgenic T2 cells, exhibiting neither conventional features of anergy nor appreciable receptor editing. Paradoxically, type-2 T-independent responses were more robust in the transgenic mice, although T-dependent responses were reduced and had skewed IgL and IgH isotype usages. Nevertheless, an augmented memory response to secondary challenge was evident. The transgenic mice also had increased serum IgM, but diminished IgG, levels mirrored by the increased numbers of IgM(+) plasma cells. This model should facilitate studies of peripheral B cell tolerance, with the advantages of allowing analysis of polyclonal populations, and of B cells naturally lacking IgD.

Effects of Rehydration on Dentin Strengthened by Heating or UV Irradiation

Type I collagen, the major organic component of human dentin, plays an important role in regulating the mechanical strength of dentin. Collagen in dentin can be strengthened by heating. We hypothesized that UV irradiation could produce similar strengthening effects and might maintain the strength of dentin after rehydration. Beam-shaped dentin specimens from the crowns of human third molars were subjected to flexural testing. Flexural strengths were two and three times greater than those in the control group after 5 minutes’ UV irradiation and heating to 140°C, respectively. After 30 days of rehydration, the heated specimens reverted to their original strength, whereas the UV specimens were 69% stronger than the original. Raman spectra of dental collagen were unchanged after heating, whereas several peaks, including a C-C bond in a proline ring, were amplified by UV irradiation. It is concluded that dentin strengthened by UV irradiation retains strength after rehydration because of chemical changes in collagen.

Decoration of T-independent antigen with ligands for CD22 and Siglec-G can suppress immunity and induce B cell tolerance in vivo

Autoreactive B lymphocytes first encountering self-antigens in peripheral tissues are normally regulated by induction of anergy or apoptosis. According to the “two-signal” model, antigen recognition alone should render B cells tolerant unless T cell help or inflammatory signals such as lipopolysaccharide are provided. However, no such signals seem necessary for responses to T-independent type 2 (TI-2) antigens, which are multimeric antigens lacking T cell epitopes and Toll-like receptor ligands. How then do mature B cells avoid making a TI-2–like response to multimeric self-antigens? We present evidence that TI-2 antigens decorated with ligands of inhibitory sialic acid–binding Ig-like lectins (siglecs) are poorly immunogenic and can induce tolerance to subsequent challenge with immunogenic antigen. Two siglecs, CD22 and Siglec-G, contributed to tolerance induction, preventing plasma cell differentiation or survival. Although mutations in CD22 and its signaling machinery have been associated with dysregulated B cell development and autoantibody production, previous analyses failed to identify a tolerance defect in antigen-specific mutant B cells. Our results support a role for siglecs in B cell self-/nonself-discrimination, namely suppressing responses to self-associated antigens while permitting rapid “missing self”–responses to unsialylated multimeric antigens. The results suggest use of siglec ligand antigen constructs as an approach for inducing tolerance.

Lymphoplasmacytic sclerosing cholangitis: assessment of clinical, CT, and pathological findings

AIM

To assess the clinical, computed tomography (CT), and pathological findings in patients with lymphoplasmacytic sclerosing cholangitis.

MATERIALS AND METHODS

Fifteen consecutive patients (four women and 11 men, mean age 71 years) with lymphoplasmacytic sclerosing cholangitis and without the characteristic features of underlying disorders causing benign biliary strictures were retrospectively recruited. Two radiologists evaluated multiphase contrast-enhanced CT images acquired with 0.5 or 1-mm collimation. One pathologist performed all histological examinations, including IgG4 immunostaining.

RESULTS

The intrahepatic biliary ducts showed dilatation in all 15 patients, but only seven presented with jaundice. Although laboratory data were not available in all patients, serum gammaglobulin and IgG levels were elevated in five of six patients and six of eight patients, respectively. Anti-nuclear antibody was detected in three of six patients. The involved biliary ducts showed the following CT findings: involvement of the hilar biliary duct (14/15), a mean wall thickness of 4.9 mm, a smooth margin (10/15), a narrow but visible lumen (6/15), hyper-attenuation during the late arterial phase (9/15), homogeneous hyper-attenuation during the delayed phase (11/11), and no vascular invasion (14/15). Abnormal findings in the pancreas and urinary tract were detected in eight of 15 patients. In 13 patients with adequate specimens, moderate to severe lymphoplasmacytic infiltration associated with dense fibrosis was observed. Infiltration of IgG4-positive plasma cells was moderate or severe in nine patients and minimal or absent in four patients.

CONCLUSION

Lymphoplasmacytic sclerosing cholangitis exhibits relatively characteristic clinical and CT findings, although they are not sufficiently specific for differentiation from other biliary diseases.

Distinct roles for E12 and E47 in B cell specification and the sequential rearrangement of immunoglobulin light chain loci

The E2A gene products, E12 and E47, are critical regulators of B cell development. However, it remains elusive whether E12 and E47 have overlapping and/or distinct functions during B lymphopoiesis. We have generated mice deficient for either E12 or E47 and examined their roles in B cell maturation. We show that E47 is essential for developmental progression at the prepro–B cell stage, whereas E12 is dispensable for early B cell development, commitment, and maintenance. In contrast, both E12 and E47 play critical roles in pre–B and immature B cells to promote immunoglobulin λ (Igλ) germline transcription as well as Igλ VJ gene rearrangement. Furthermore, we show that E12 as well as E47 is required to promote receptor editing upon exposure to self-antigen. We demonstrate that increasing levels of E12 and E47 act to induce Igλ germline transcription, promote trimethylated lysine 4 on histone 3 (H3) as well as H3 acetylation across the Jλ region, and activate Igλ VJ gene rearrangement. We propose that in the pre–B and immature B cell compartments, gradients of E12 and E47 activities are established to mechanistically regulate the sequential rearrangement of the Ig light chain genes.

Suppression of IgE B cells and IgE binding to Fc(epsilon)RI by gene therapy with single-chain anti-IgE

IgE plays a pivotal role in allergic reactions and asthma through its ability to bind to the mast cell FcR for IgE (FcepsilonRI). Current therapies to suppress such reactions include passive treatment with neutralizing Abs to IgE that block its binding to FcepsilonRI. In theory, induction of immune tolerance in the B lymphocytes that carry IgE Ag receptors and give rise to IgE-secreting cells should provide longer term efficacy. However, recent data have suggested that such memory cells may lack cell surface IgE. Using a gene therapy approach, we show that a recombinant single-chain neutralizing anti-IgE could not only neutralize circulating IgE, but also reduce IgE(+) B cell numbers and H chain transcripts. Therapeutic anti-IgE stimulated a calcium response in primary B cells or in a B cell line expressing membrane IgE and suppressed IgE secretion in vitro, suggesting that active signaling through membrane IgE likely promoted tolerance. Interestingly, upon subsequent challenge of anti-IgE-treated mice with an IgE cross-linking reagent capable of inducing activation of IgE-decorated mast cells, an anaphylaxis reaction was induced, apparently via a FcgammaRIII pathway involving recognition of anti-IgE Ab itself. These studies have important implications for the optimal design of safe and effective anti-IgE therapies and suggest that the IgE memory B cells may be targeted by such genetic Ab therapies.

Mapping of brain acetylcholinesterase alterations in Lewy body disease by PET

OBJECTIVE

To characterize brain cholinergic deficits in Parkinson disease (PD), PD with dementia (PDD), and dementia with Lewy bodies (DLB).

METHODS

Participants included 18 patients with PD, 21 patients with PDD/DLB, and 26 healthy controls. The PD group consisted of nine patients with early PD, each with a disease duration of less than 3 years, five of whom were de novo PD patients, and nine patients with advanced PD, each with a disease duration greater than or equal to 3 years. The PDD/DLB group consisted of 10 patients with PDD and 11 patients with DLB. All subjects underwent PET scans with N-[11C]-methyl-4-piperidyl acetate to measure brain acetylcholinesterase (AChE) activity. Brain AChE activity levels were estimated voxel-by-voxel in a three-compartment analysis using the arterial input function, and compared among our subject groups through both voxel-based analysis using the statistical parametric mapping software SPM5 and volume-of-interest analysis.

RESULTS

Among patients with PD, AChE activity was significantly decreased in the cerebral cortex and especially in the medial occipital cortex (% reduction compared with the normal mean = -12%) (false discovery rate-corrected p value <0.01). Patients with PDD/DLB, however, had even lower AChE activity in the cerebral cortex (% reduction = -27%) (p < 0.01). There was no significant difference between early PD and advanced PD groups or between DLB and PDD groups in the amount by which regional AChE activity in the brain was reduced.

CONCLUSIONS

Brain cholinergic dysfunction occurs in the cerebral cortex, especially in the medial occipital cortex. It begins in early Parkinson disease, and is more widespread and profound in both Parkinson disease with dementia and dementia with Lewy bodies.

A comparison of interface pressure and stiffness between elastic stockings and bandages

Objectives

To compare the interface pressure during posture changes and exercise between elastic stockings and bandages.

Methods

Using a pressure transducer (air pack-type analyzer), the interface pressures associated with three different elastic stockings and three different elastic bandages were measured during supine resting, standing and exercise in 15 healthy volunteers.

Results

Short-stretch bandages showed a significantly higher static stiffness index value, which is defined as the pressure difference between lying and standing, than long-stretch bandages and short-stretch stockings ( P < 0.001). Furthermore, short-stretch bandages showed a significantly greater pressure difference between muscle contraction and relaxation in both tip-toe and knee-bending exercises than long-stretch bandages and short-stretch stockings ( P < 0.001).

Conclusion

Short-stretch bandages can be expected to have more pronounced benefits for augmenting muscle pump than long-stretch bandages and short-stretch stockings.

Clinicopathologic and prognostic features of triple-negative breast cancer analyzed in registration data of the Japanese Breast Cancer Society, 11705 cases

e22122

Background: Triple-negative (TN) breast cancers which are negative for ER, PgR, and HER2 by immunohistochemistry are associated with a poor prognosis. To clarify the characteristics of TN tumors, the data of the registration committee of the Japanese Breast Cancer Society were analyzed with respect to clinicopathologic factors, response to neoadjuvant chemotherapy (NAC) and prognosis. Methods: Of 14,748 cases that were registered in 2004, 11,705 cases (79.4%) were examined for ER, PgR, and HER2 status, which was based on local institute. In the 2,331 cases of all registered cases, the prognosis and details of the treatment were analyzed with 47.8 months as median follow-up period. In 184 cases (7.9%), NAC was mainly performed using anthracycline and taxane based chemotherapy. Results: Luminal A type with positive for ER and/or PgR and negative for HER2 was most prevalent (53.8%), followed by TN type (15.5%). TN cancers were diagnosed at a slightly advanced stage and more of the cases had lymph node metastases compared to other types. Mucinous or tubular carcinoma was frequently seen in the Luminal A type. Squamous cell, spindle cell carcinoma, or metaplastic carcinoma with bone/cartilage metaplasia was found in only TN type. The HER2 type and TN type had statistically worse outcome compared to Luminal type in DFS and OS (P<.0001 and P<.0001, respectively). Pathological response rate of NAC, including grade 2 and 3, was higher in TN tumor as 51.5 % (22/53) than in Luminal A tumor as 16.7% (12/72). Responders in TN tumors have a better prognosis than non-responder (P=.0016), but this tendency was not recognized in non-TN tumors (P=.15). Conclusions: The ratio of the TN tumors in Japan was 15–6%. Central reviews of immunohistochemistry, such as ER, PgR, HER2, CK5/6, EGFR etc, will be confirmed in this cohort, for TN tumors are similar to basal-like tumors discriminated by gene- profiling.

[Table: see text]

A novel signal processing method using system identification for underwater surface electromyography

PURPOSE

Currently, to record underwater surface electromyography (EMG), electrodes are covered with waterproof tape. For short-term measurement, waterproof tape prevents electrical leakage. However, during long-term measurement, water or sweat can contact the electrodes, changing the measurement conditions and gradually affecting the EMG data. The purpose of present study was to devise a novel method for prolonged underwater EMG recording, which estimate dry-land EMG from underwater EMG recorded by non-waterproofed electrodes using system identification techniques.

METHOD

One healthy male participated in this study. System identification was used to convert underwater EMG signals to the estimated dry-land signals. Transfer functions were derived using two pairs of surface recording electrodes on the same muscle in parallel. System input was the EMG recorded using non-waterproofed electrodes; the output was the signal recorded underwater using waterproofed electrodes (supposed to be the same as dry-land signals). To examine the validity of the present method, three experiments were conducted.

RESULT

There was a high positive correlation between the estimated dry-land EMG based on the non-waterproofed electrodes and the EMG obtained using waterproofed electrodes. To test the validity of long-term recording using the novel method, the estimated dry-land EMG signals were measured during 30 minutes of underwater stepping and were stable.

CONCLUSION

The novel method using non-waterproofed electrodes with system identification techniques eliminated the effect of changes in measurement conditions and appears effective for long-term, underwater surface EMG recording.

Boundary-mediated electron-electron interactions in quantum point contacts

An unusual increase of the conductance with temperature is observed in clean quantum point contacts for conductances larger than 2(e2/h). At the same time, a positive magnetoresistance arises at high temperatures. A model accounting for electron-electron interactions mediated by boundaries (scattering on Friedel oscillations) qualitatively describes the observation. It is supported by a numerical simulation at zero magnetic field.

Improved traction for a mobile robot traveling on the heart

This document describes the effects of several design parameters on the traction generated by the suction pads of a mobile robot that walks on the surface of the heart. HeartLander is a miniature mobile robot that adheres to the epicardial surface of the heart using suction, and can travel to any desired location on the heart to administer therapeutic applications. To maximize the effectiveness of locomotion, the gripper pads must provide sufficient traction to avoid slipping. Our testing setup measured the force applied to the gripper pad adhering to ovine epicardial tissue, and recorded overhead video for tracking of the pad and tissue during an extension. By synchronizing the force and video data, we were able to determine the point at which the pad lost traction and slipped during the extension. Of the pads tested, the pad with no suction grate achieved maximum traction. Increasing the extension speed up to 20 mm/s resulted in a corresponding increase in traction. Increasing the vacuum pressure also improved the traction, but the magnitude of the effect was less than the improvement gained from increasing extension speed.

Rearrangement of mouse immunoglobulin kappa deleting element recombining sequence promotes immune tolerance and lambda B cell production

The recombining sequence (RS) of mouse and its human equivalent, the immunoglobulin (Ig) kappa deleting element (IGKDE), are sequences found at the 3' end of the Ig kappa locus (Igk) that rearrange to inactivate Igk in developing B cells. RS recombination correlates with Ig lambda (Iglambda) light (L) chain expression and likely plays a role in receptor editing by eliminating Igk genes encoding autoantibodies. A mouse strain was generated in which the recombination signal of RS was removed, blocking RS-mediated Igk inactivation. In RS mutant mice, receptor editing and self-tolerance were impaired, in some cases leading to autoantibody formation. Surprisingly, mutant mice also made fewer B cells expressing lambda chain, whereas lambda versus kappa isotype exclusion was only modestly affected. These results provide insight into the mechanism of L chain isotype exclusion and indicate that RS has a physiological role in promoting the formation of lambda L chain-expressing B cells.

The origin of the premotor potential recorded from the second lumbrical

PURPOSE

When recording with a palm electrode, a premotor potential (PMP) precedes the compound muscle action potential evoked from the second lumbrical muscle following median nerve stimulation. The origin of the premotor potential has remained uncertain. The aim of this study was to determine whether the PMP-2L is a SNAP derived from antidromically activated digital sensory branches of the median nerve.

METHODS

We recorded three active electrodes were placed over the second lumbrical muscle, the third lumbrical muscle, the fourth lumbrical muscle by multi-channel recordings.

RESULTS

PMPs are recorded only over the median digital sensory branches after stimulating the median nerve, while they are recorded only over the ulnar branch after stimulating the ulnar nerve.

CONCLUSIONS

We conclude that the origin of the PMP is a SNAP arising from antidromically activated digital sensory branches.

[Mitral valve replacement for cabergoline-related severe mitral regurgitation]

An 82-year-old man was referred to our hospital because of progressive heart failure. He had Parkinson's disease and had been treated with cabergoline during the preceding 4 years and 8 months. Echocardiography revealed severe mitral regurgitation through retracted mitral leaflets with incomplete coaptation. Heart failure persisted despite pharmacologic therapy, so the mitral valve was surgically replaced with a biological valve. Histologic analysis showed fibrous thickened mitral chordae with myxoid degeneration. These characteristics of the mitral valve of our patient are similar to the valvular heart disease described with the use of cabergoline. Clinicians must be care of valvular heart disease whenever they treat Parkinson's disease patients with cabergoline.

Treatment of squamous cell carcinoma of the uterine cervix with radiation therapy alone: long-term survival, late complications, and incidence of second cancers

The objective of this retrospective study was to determine the survival rate, incidence of late complications, and incidence of second cancers when radiation therapy alone is used for carcinoma of the uterine cervix. Between 1971 and 1995, 1495 patients with squamous cell carcinoma of the uterine cervix (stages I–IV) were treated with radiation therapy alone in our hospital. Radiation therapy consisted of a combination of high-dose-rate intracavitary brachytherapy and external beam radiotherapy. The cumulative 5-year survival rates for stages Ib, II, and III/IVa carcinoma were 93.5, 77.0, and 60.3%, respectively, and the 10-year survival rates were 90.9, 74.5, and 56.1%, respectively. Local control rates for stages Ib, II, and III/IVa carcinoma were 92.0, 79.4 and 64.2%, respectively. Eighty-two (5.5%) patients suffered grade III/IV or V (fatal) complications. A second cancer developed in 13 (0.87%) patients. Second cancers were observed most frequently in the rectum (five cases), colon (three cases), and uterine body (two cases). Long-term follow-up data revealed that our method of radiation therapy alone for locally advanced carcinoma of the uterine cervix is effective, with low incidences of late complications and second cancers.

Anomalous resistance ridges along filling factor nu=4i

We report anomalous structure in the magnetoresistance of SiO(2)/Si(100)/SiO(2) quantum wells. When Landau levels of opposite valleys are driven through coincidence at the Fermi level, the longitudinal resistance displays elevations at filling factors that are integer multiples of 4 (nu=4i) accompanied by suppression on either side of nu=4i. This persists when either the magnetic field or the valley splitting is swept, leading to resistance ridges running along nu=4i. The range of field over which they are observed points to the role of spin degeneracy, which is directly confirmed by their disappearance with the addition of an in-plane magnetic field. The data suggest a new type of many-body effect arising from the combined degeneracy due to the valley and the spin degrees of freedom.

Automated discrimination between very early Alzheimer disease and controls using an easy Z-score imaging system for multicenter brain perfusion single-photon emission tomography

BACKGROUND AND PURPOSE

In Alzheimer disease (AD), a peculiar regional cerebral blood flow (rCBF) abnormality has been reported in the posterior cingulate gyri and precunei, even at a very early stage. We performed a multicenter brain perfusion single-photon emission tomography (SPECT) study to evaluate the discrimination ability of an easy Z-score imaging system (eZIS) with a common normal data base between patients with very early AD at the stage of mild cognitive impairment and age-matched healthy controls.

MATERIALS AND METHODS

For a multicenter study, SPECT images of 40 patients with AD and 40 healthy volunteers were acquired from 4 gamma camera systems in 4 different institutions. Systematic differences of SPECT images between gamma cameras were corrected by using conversion maps calculated from the SPECT images of the same brain phantom. Receiver operating characteristic (ROC) analysis was performed to discriminate patients and controls by using a Z-score in the volume of interest (VOI), which had been defined as a region related to AD in subjects other than those in a multicenter study.

RESULTS

Bilateral posterior cingulate gyri, precunei, and parietal cortices were defined as a VOI showing rCBF reduction in very early AD. A new indicator of rCBF abnormality in the VOI provided 86% accuracy for distinction of AD and healthy controls in the multicenter study. The area under the ROC curve was 0.934.

CONCLUSION

Because an eZIS can use a common normal data base by converting site-specific SPECT data to the core data, the eZIS was useful for automated diagnosis of very early AD in routine studies in multiple institutions.

Genes involved in oxidative phosphorylation are coordinately upregulated with fasting hyperglycaemia in livers of patients with type 2 diabetes

AIMS/HYPOTHESIS

Mitochondrial oxidative phosphorylation (OXPHOS) plays an important role in the pathophysiology of type 2 diabetes. Genes involved in OXPHOS have been reported to be down-regulated in skeletal muscle from patients with type 2 diabetes; however, hepatic regulation is unknown.

MATERIALS AND METHODS

We analysed expression of genes involved in OXPHOS from the livers of 14 patients with type 2 diabetes and 14 subjects with NGT using serial analysis of gene expression (SAGE) and DNA chip analysis. We evaluated the correlation between expression levels of genes involved in OXPHOS and the clinical parameters of individuals with type 2 diabetes and NGT.

RESULTS

Both gene analyses showed that genes involved in OXPHOS were significantly upregulated in the type 2 diabetic liver. In the SAGE analysis, tag count comparisons of mitochondrial transcripts showed that ribosomal RNAs (rRNA) were 3.5-fold over-expressed, and mRNAs were 1.2-fold over-expressed in the type 2 diabetes library. DNA chip analysis revealed that expression of genes involved in OXPHOS, which correlated with several nuclear factors, including estrogen-related receptor-alpha or peroxisome proliferator-activated receptor-gamma, was a predictor of fasting plasma glucose levels, independently of age, BMI, insulin resistance and fasting insulin levels (p = 0.04). Surprisingly, genes involved in OXPHOS did not correlate with peroxisome proliferator-activated receptor-gamma coactivator-1alpha or nuclear respiratory factor 1.

CONCLUSIONS/INTERPRETATION

Our results indicate that upregulation of genes involved in OXPHOS in the liver, which are regulated by different mechanisms from genes in the skeletal muscle, is associated with fasting hyperglycaemia in patients with type 2 diabetes.

D. Adjuvant-enhanced antibody responses in the absence of toll-like receptor signaling

Innate immune signals mediated by Toll-like receptors (TLRs) have been thought to contribute considerably to the antibody-enhancing effects of vaccine adjuvants. However, we report here that mice deficient in the critical signaling components for TLR mount robust antibody responses to T cell-dependent antigen given in four typical adjuvants: alum, Freund's complete adjuvant, Freund's incomplete adjuvant, and monophosphoryl-lipid A/trehalose dicorynomycolate adjuvant. We conclude that TLR signaling does not account for the action of classical adjuvants and does not fully explain the action of a strong adjuvant containing a TLR ligand. This may have important implications in the use and development of vaccine adjuvants.

Albumin induces endoplasmic reticulum stress and apoptosis in renal proximal tubular cells

Chronic proteinuria appears to be a key factor in tubulointerstitial damage. Recent studies have emphasized a pathogenic role of endoplasmic reticulum (ER) stress which is induced by the accumulation of misfolded proteins in ER, extracellular stress, etc. In the present study, we investigated ER stress and ER stress-induced apoptosis in proximal tubular cells (PTCs). Immortalized rat PTCs (IRPTCs) were cultured with bovine serum albumin (BSA). The viability of IRPTCs decreased proportionately with BSA overload in a time-dependent manner. Quantitative real-time polymerase chain reaction analysis revealed that 40 mg/ml BSA increases mRNA of ER stress markers by 7.7- and 4.6-fold (glucose-regulated protein 78 (GRP78) and oxygen-regulated protein 150 (ORP150), respectively) as compared to control. The increased expression of ORP150 and GRP78 in IRPTCs with albumin overload was detected by Western blot and immunofluorescence study. These in vitro observations were supported by in vivo studies, which demonstrated that ER stress proteins were upregulated at PTCs in experimental proteinuric rats. Furthermore, increased ER stress-induced apoptosis and activation of caspase-12 were observed in IRPTCs with albumin overload and kidneys of experimental proteinuric rats. We confirmed that apoptotic cell death was attenuated by co-incubation with caspase-3 inhibitor or calpain inhibitors. These results indicate that the ER stress-induced apoptosis pathway contributed to the insult of tubular cells by proteinuria. In conclusion, renal tubular cells exposed to high protein load suffer from ER stress. ER stress may subsequently lead to tubular damage by activation of caspase-12.

Tolerance induction by the blockade of CD40/CD154 interaction in pemphigus vulgaris mouse model

Pemphigus vulgaris (PV) is an autoimmune blistering disease caused by IgG autoantibodies against desmoglein 3 (Dsg3). We have recently developed an active disease mouse model for PV by adoptive transfer of splenocytes from Dsg3(-/-) mice. The purpose of this study was to determine the role of CD40/CD154 interaction in the pathogenic antibody production and development of the disease in PV model mice. When anti-CD154 monoclonal antibody (mAb) was administered to recipient mice prior to adoptive transfer, anti-CD154 mAb almost completely blocked the anti-Dsg3 IgG production and prevented blister formation. The blockade of CD40/CD154 interaction induced tolerance against Dsg3 as the suppression of antibody production was observed through day 70, and it was maintained even after challenge by immunization with recombinant mouse Dsg3 or by adoptive transfer of immunized Dsg3(-/-) splenocytes. Furthermore, the tolerance to Dsg3 was transferable because cotransfer of splenocytes from anti-CD154 mAb-treated mice and naïve Dsg3(-/-) splenocytes significantly suppressed anti-Dsg3 IgG production in recipient mice. In contrast, when anti-CD154 mAb was injected after the mice had developed the PV phenotype, no significant suppression of the production of anti-Dsg3 IgG was observed. These findings indicate that the CD40/CD154 interaction is essential for the induction of pathogenic anti-Dsg3 IgG antibodies and that antigen-specific immune-regulatory cells induced by anti-CD154 mAb would hold a therapeutic option for autoimmune diseases.

Few-electron molecular states and their transitions in a single InAs quantum dot molecule

We study electronic configurations in a single pair of vertically coupled self-assembled InAs quantum dots, holding just a few electrons. By comparing the experimental data of nonlinear single-electron transport spectra in a magnetic field with many-body calculations, we identify the spin and orbital configurations to confirm the formation of molecular states by filling both the quantum mechanically coupled symmetric and antisymmetric states. Filling of the antisymmetric states is less favored with increasing magnetic field, and this leads to various magnetic field induced transitions in the molecular states.

Down-regulation of a morphogen (sonic hedgehog) gradient in the gastric epithelium of Helicobacter pylori-infected Mongolian gerbils

Sonic hedgehog (Shh) is a morphogen involved in many aspects of patterning of the gut during embryogenesis and in gastric fundic gland homeostasis in the adult. Intestinal metaplastic change of the gastric epithelium is associated with the loss of Shh expression, and mice that lack Shh expression show intestinal transformation of the gastric mucosa. The present study was designed to investigate the alteration of Shh expression in the stomach of an experimental model of Helicobacter pylori (H. pylori) colonization. Male Mongolian gerbils were inoculated with H. pylori and examined 4 and 51 weeks later. The level of Shh mRNA expression was determined by quantitative RT-PCR and in situ hybridization. Shh protein expression was determined by immunoblotting and immunohistochemistry. Shh was expressed in the parietal cells, zymogenic cells, and mucous neck cells of the gastric fundic glands of gerbils. Prolonged colonization by H. pylori led to extension of the inflammation from the antrum to the corpus of the stomach, with loss of Shh expression. Loss of Shh expression correlated with loss of parietal cells, disturbed maturation of the mucous neck cell-zymogenic cell lineage, and increased cellular proliferation. Shh expression is significantly reduced in H. pylori-associated gastritis. These data show for the first time that H. pylori infection leads to down-regulation of the expression of a morphogen with an established role (Shh) in gastric epithelial differentiation.

Clinicopathologic study of uterine endometrial carcinoma in young women aged 40 years and younger

To clarify what constitutes the adequate management of uterine endometrial carcinoma in young women, we reviewed clinicopathologically 31 patients aged 40 years and younger between January 1991 and June 2004. As a primary treatment, 12 cases chose hormonal treatment with medroxyprogesterone acetate (MPA; 600 mg/day) due to no findings of myometrial invasion and diagnosis of a grade 1, well-differentiated adenocarcinoma. In remaining 19 cases, surgery was performed. All the 19 patients who received surgery as a primary treatment are alive, with no evidence of a recurrence of the disease. In the 12 patients who received hormonal treatment, 8 patients eventually received a hysterectomy because of recurrence or no response to MPA. Of these eight patients, myometrial invasion was recognized in three patients. One of the eight patients died of the metastasized disease to the liver and brain after hysterectomy. After hormonal treatment, 4 of the 12 patients were exempted from surgery and showed no evidence of recurrence. Two patients had viable children. Progesterone receptor was negative in one case that died. Careful consideration should be given to hormonal treatment with MPA for the conservative management of endometrial carcinoma in young women. Moreover, MPA is not always a consistent management for every patient.

In vivo ultrastructural localization of the desmoglein 3 adhesive interface to the desmosome mid-line

Desmoglein (Dsg) is a cadherin cell-cell adhesion molecule located in desmosomes and its precise mechanism for cell-cell adhesion still remains to be elucidated. Opposing cadherin molecules may adhere to the N-terminal EC1 domains, or the entire length of the extracellular (EC) domains may overlap. To solve this controversy, we performed immunoelectron microscopy to map the Dsg3 epitopes in desmosomes. Three different hybridoma cell lines producing anti-Dsg3 monoclonal antibodies (mAb) were intraperitoneally injected into immunodeficient mice and the precise ultrastructural location of bound IgG between the mucosal epithelial cells in vivo was statistically measured and analyzed. The binding site of the AK23 mAb that recognizes the N-terminal EC1 domain was localized to the electron-dense mid-line of desmosomes. The binding sites of AK7 and AK18, which recognize the C-terminal membrane proximal and middle portions of the EC domains, were localized to the desmosomal region proximal to the membrane and the region between the plasma membrane and the dense mid-line, respectively. These results indicate that the N-terminal regions of Dsg3 from opposing cells interact at the dense mid-line of desmosomes where EC1 overlaps.

Clinicopathologic study of uterine endometrial carcinoma in young women aged 40 years and younger

To clarify what constitutes the adequate management of uterine endometrial carcinoma in young women, we reviewed clinicopathologically 31 patients aged 40 years and younger between January 1991 and June 2004. As a primary treatment, 12 cases chose hormonal treatment with medroxyprogesterone acetate (MPA; 600 mg/day) due to no findings of myometrial invasion and diagnosis of a grade 1, well-differentiated adenocarcinoma. In remaining 19 cases, surgery was performed. All the 19 patients who received surgery as a primary treatment are alive, with no evidence of a recurrence of the disease. In the 12 patients who received hormonal treatment, 8 patients eventually received a hysterectomy because of recurrence or no response to MPA. Of these eight patients, myometrial invasion was recognized in three patients. One of the eight patients died of the metastasized disease to the liver and brain after hysterectomy. After hormonal treatment, 4 of the 12 patients were exempted from surgery and showed no evidence of recurrence. Two patients had viable children. Progesterone receptor was negative in one case that died. Careful consideration should be given to hormonal treatment with MPA for the conservative management of endometrial carcinoma in young women. Moreover, MPA is not always a consistent management for every patient

Aberrant promoter methylation in human DAB2 interactive protein (hDAB2IP) gene in gastrointestinal tumour

The human DOC-2/DAB2 interactive protein (hDAB2IP) gene is a novel member of the Ras GTPase-activating family and has been demonstrated to be a tumour-suppressor gene inactivated by methylation in several cancers. In this study, we analysed the methylation and expression status of hDAB2IP in gastrointestinal tumours. The promoter region of hDAB2IP was divided into two regions (m2a and m2b) based on our previous report, and the methylation status was determined by bisulphite DNA sequencing in gastric cancer cell lines. The gene expression was semiquantified by real-time RT–PCR, and the results indicated that the m2b promoter region might be an authentic methylation-mediated key regulator of the gene expression. Based on the sequence data, we developed a methylation-specific PCR (MSP) for the m2a and m2b regions and applied it to the samples. Methylation-specific PCR revealed aberrant methylation in the m2a region in eight of 12 gastric cancer cell lines (67%), 16 of 35 gastric cancer tissues (46%) and 29 of 60 colorectal cancer tissues (48%), and in the m2b region in eight of 12 cell lines (67%), 15 of 35 gastric cancer tissues (43%) and 28 of 60 colorectal cancer tissues (47%). On the other hand, seven (12%) and 11 (19%) of 59 gastrointestinal nonmalignant mucosal specimens showed methylation in the m2a and m2b regions, respectively, suggesting that hDAB2IP methylation might play a causative role in carcinogenesis. The 5-aza-2′-deoxycytidine treatment restored the gene expression in the m2b-methylated cell lines, confirming that the methylation caused gene downregulation. We also examined the relationship between hDAB2IP methylation and the clinicopathological features in patients with primary tumours, and determined that methylation in the m2b region was associated with location of the tumour in the stomach. In summary, our results demonstrated that hDAB2IP methylation is frequently present in gastrointestinal tumours and that the resulting gene silencing plays an important role in gastrointestinal carcinogenesis.

Multiple organ failure caused by end-stage liver disease successfully treated with living donor liver transplantation using perioperative percutaneous cardiopulmonary support: a case report

A 54-year-old female diagnosed with primary biliary cirrhosis (PBC) 10 years earlier was referred for a living donor liver transplant (LDLT). During her workup, she developed pulmonary edema and respiratory failure due to aspiration pneumonia, which required artificial ventilation. The PaO2/FiO2 (P/F) ratio at that time was 60. Although continuous hemodiafiltration (CHDF) and plasma exchange (PE) were initiated, improvement in the P/F ratio was limited to 133. As transplantation was the only approach to save this patient, we performed LDLT using a right lobe graft aided by percutaneous cardiopulmonary support (PCPS). The graft weight was 650 g and the graft weight/recipient weight ratio was 1.6%. During LDLT, the patient's cardiopulmonary function was stable with PCPS, and the surgical procedure was completed without complications. Following the surgery, she continued to have high-end inspiratory pressure and progressed to the chronic phase of adult respiratory distress syndrome (ARDS). We treated her with low-dose steroid therapy and she improved gradually. The patient was weaned off mechanical ventilation and was discharged approximately 25 weeks after LDLT. In the condition of cardiac or respiratory failure, cadaveric liver transplantation using plasmapheresis is contraindicated because of the associated high mortality rate. Our case suggests that if infections are controlled, a patient with multiple organ failure (MOF) due to end-stage liver disease might be successfully treated with LDLT aided by plasmapheresis and PCPS.

Genetic identification and detection of human pathogenic Rhizopus species, a major mucormycosis agent, by multiplex PCR based on internal transcribed spacer region of rRNA gene

BACKGROUND

Mucormycosis is an invasive opportunistic infection caused by fungi belonging to the order Mucorales. Due to the lack of laboratory tests, the diagnosis of mucormycosis is notoriously difficult. Added with its rapid progression as well as the debilitated state of the patients who contract the disease, mortality is extremely high.

OBJECTIVE

The goal of this study was to genetically identify human pathogenic Rhizopus species, a major mucormycosis agent, by the internal transcribed spacer (ITS) region of rRNA gene.

METHODS

Primers were designed to identify five Rhizopus species known to cause human disease by multiplex PCR. PCR was done not only with test strains and clinical isolates, but also with clinical samples from cutaneous mucormycosis patients. Sporangiospore morphology was observed by scanning electron microscopy to confirm the correlation of phenotypic and genotypic features.

RESULTS

Multiplex PCR identified five Rhizopus species including Rhizopus oryzae, where R. azygosporus could only be distinguished from R. microsporus by certain polymorphisms that were present in its sequence. When this multiplex PCR was applied to clinical samples from three mucormycosis patients (paraffin sections from all and sera from one patient), Rhizopus DNA corresponding to the isolated pathogens were specifically detected.

CONCLUSION

While fungal DNA detection from clinical samples is a rigorously studied area, this is the first report to genetically identify and detect Rhizopus species from human mucormycosis specimens. This may expand the possibility of this multiplex PCR system not only to identify isolated fungi, but also as a screening method for visceral mucormycosis.

A mouse model of pemphigus vulgaris by adoptive transfer of naive splenocytes from desmoglein 3 knockout mice

BACKGROUND

Pemphigus vulgaris (PV) is an autoimmune blistering disease caused by antidesmoglein3 (anti-Dsg3) IgG autoantibodies. Recently, we developed a PV mouse model by adoptive transfer of splenocytes from recombinant Dsg3-immunized Dsg3(-/-) mice to Rag2(-/-) immunodeficient mice that expressed Dsg3.

OBJECTIVES

We determined whether the adoptive transfer of naive splenocytes from nonimmunized Dsg3(-/-) mice induces the anti-Dsg3 IgG production and the PV phenoytpe in recipient mice.

METHODS

We adoptively transferred naive Dsg3(-/-) splenocytes into Rag2(-/-) mice and compared their PV phenoytpe with those mice receiving immunized Dsg3(-/-) splenocytes. The numbers of splenocytes and their subpopulations required for anti-Dsg3 IgG production were examined.

RESULTS

Mice that received naive Dsg3(-/-) splenocytes produced anti-Dsg3 IgG, which bound to keratinocyte cell surfaces in vivo, and developed the PV phenotype, including oral erosions with suprabasilar acantholysis. Antibody production and the appearance of the PV phenotype were delayed by approximately 2 weeks in mice that received naive splenocytes compared with mice that received immunized splenocytes. However, once the PV phenotypes developed, there were no apparent differences in disease severity between the two models. Interestingly, the anti-Dsg3 IgG titres were significantly lower in mice that received naive splenocytes than in mice that received immunized splenocytes, suggesting that the former antibodies were more potent than the latter. The frequency of anti-Dsg3 IgG production depended on the number of transferred naive splenocytes. Both CD4+ T cells and B220+ B cells from naive Dsg3(-/-) mice were essential for the production of anti-Dsg3 IgG antibodies.

CONCLUSIONS

Dsg3-specific naive lymphocytes in Dsg3(-/-) mice can be primed and activated by the endogenous Dsg3 in recipient mice to produce pathogenic anti-Dsg3 IgG without active immunization. This approach using naive lymphocytes provides a unique model to dissect immunological mechanisms of tolerance against peripheral autoimmune targets.