The receptor LMIR3 negatively regulates mast cell activation and allergic responses by binding to extracellular ceramide.

Mast cells (MCs) are key effector cells in allergic reactions. However, the inhibitory mechanism that prevents excessive activation of MCs remains elusive. Here we show that leukocyte mono-immunoglobulin-like receptor 3 (LMIR3; also called CD300f) is a negative regulator of MC activation in vivo. LMIR3 deficiency exacerbated MC-dependent allergic responses in mice, including anaphylaxis, airway inflammation, and dermatitis. Both physical binding and functional reporter assays via an extracellular domain of LMIR3 showed that several extracellular lipids (including ceramide) and lipoproteins were possible ligands for LMIR3. Importantly, MCs were frequently surrounded by extracellular ceramide in vivo. Upon engagement of high-affinity immunoglobulin E receptor, extracellular ceramide-LMIR3 binding inhibited MC activation via immunoreceptor tyrosine-based inhibitory and switch motifs of LMIR3. Moreover, pretreatment with LMIR3-Fc fusion protein or antibody against either ceramide or LMIR3 interfered with this binding in vivo, thereby exacerbating passive cutaneous anaphylaxis. Thus, the interaction between extracellular ceramide and LMIR3 suppressed MC-dependent allergic responses.

First case of an invasive Bacteroides dorei infection detected in a patient with a mycotic aortic aneurysm-raising a rebellion of major indigenous bacteria in humans: a case report and review.

BACKGROUND: Bacteroides dorei is an anaerobic gram-negative bacterium first described in 2006. Because of the high similarity in mass spectra between B. dorei and Bacteroides vulgatus, discriminating between these species is arduous in clinical practice. In recent decades, 16S rRNA gene sequencing has been a complementary method for distinguishing taxonomically close bacteria, including B. dorei and B. vulgatus, at the genus and species levels. Consequently, B. dorei has been shown to contribute to some diseases, including type 1 autoimmune diabetes mellitus and atherosclerotic diseases. However, there are no reports on invasive infectious diseases caused by B. dorei. This report describes the first case of direct invasion and colonisation of human tissue by B. dorei, thus providing a warning regarding the previously proposed application of B. dorei as a live biotherapeutic for atherosclerotic diseases. CASE PRESENTATION: A 78-year-old Japanese man complained of intermittent chest/back pain and was diagnosed with a mycotic thoracic aortic aneurysm by enhanced computed tomography on admission. Despite strict blood pressure control and empirical antibiotic therapy, the patient's condition worsened. To prevent aneurysmal rupture and eliminate infectious foci, the patient underwent surgical treatment. The resected specimen was subjected to tissue culture and 16S rRNA gene sequencing analysis to identify pathogenic bacteria. A few days after the surgery, culture and sequencing results revealed that the pathogen was B. dorei/B. vulgatus and B. dorei, respectively. The patient was successfully treated with appropriate antibacterial therapy and after improvement, was transferred to another hospital for rehabilitation on postoperative day 34. There was no recurrence of infection or aneurysm after the patient transfer. CONCLUSIONS: This report describes the first case of invasive infectious disease caused by B. dorei, casting a shadow over its utilisation as a probiotic for atherosclerotic diseases.

[Aortic Root Pseudoaneurysm due to Avulsion of Aortic Valve Commissure Following to Infective Endocarditis;Report of a case].

A 40-year-old man presented to our hospital with fever and slight palpitation. The echocardiogram revealed bicuspid aortic valve, massive aortic regurgitation, and aneurysm of Valsalva sinus. Operative findings showed an aortic root pseudoaneurysm originating just below the avulsion of the right to left commissure. The orifice was closed with a part of a woven vascular graft, and the aortic valve was replaced with a mechanical valve. There was no sign of marked inflammation, although pathophysiologic findings indicated infective endocarditis. His postoperative course was uneventful.

Non-occlusive mesenteric ischemia after trans-catheter aortic valve implantation with thyroid storm: A case report.

Non-occlusive mesenteric ischemia (NOMI) is a rare but well-known life-threatening disease. However, reports on NOMI following trans-catheter aortic valve implantation (TAVI) are limited. This report presents a case of NOMI after trans-apical (TA) TAVI with thyroid storm. A 73-year-old man was admitted for a planned aortic valve surgery. Because he had severe aortic calcification and a right renal tumor that was suspected to be malignant, TA-TAVI was performed. At 61 h after TAVI, the patient complained of abdominal pain, and contrast-enhanced computed tomography showed ischemic necrosis of the cecum to the ascending colon. An ileocecal resection was performed emergently. He was extubated 61 h postoperatively, but severe delirium, high fever, and atrial fibrillation persisted. Due to a history of Basedow's disease, he was diagnosed with thyroid storm and treated with thiamazole and supportive care. The general status gradually improved, and he was transferred to the rehabilitation unit on the 17th postoperative day. We encountered a case of NOMI following TA-TAVI with a thyroid storm, which made it difficult to understand the patient's medical condition. Learning objective: The occurrence of non-occlusive mesenteric ischemia after trans-catheter aortic valve implantation is rare but possible, and a thyroid storm could occur even after a less invasive surgery. It is important to perform postoperative management while considering the possible occurrence of this condition.

A Case of Alport Syndrome Associated with Recurrent Stanford Type B Aortic Dissections.

Alport syndrome is often characterized by renal dysfunction and hearing loss due to abnormalities in type IV collagen production. In this study, we report a rare case of recurrent aortic dissections that developed in a young patient with Alport syndrome over a short period. We discuss the associations between Alport syndrome and aortic dissection with a literature review and emphasize the need for regular follow-up of patients with Alport syndrome for early detection of aortic disease.

Infective Endocarditis with a Left Ventricular Pseudoaneurysm Caused by Proteus mirabilis: A Case Report.

Infective endocarditis (IE) due to Proteus mirabilis is rare. Given that cases of IE complicated with a left ventricular pseudoaneurysm (LVP) caused by P. mirabilis have not been reported thus far, here we report a case of IE complicated with an LVP caused by P. mirabilis. An 83-year-old woman was admitted to our hospital for urinary tract infection, and P. mirabilis was detected in blood cultures. Transesophageal echocardiography and electrocardiogram-gated computed tomography revealed mitral regurgitation and a mass protruding from the mitral annulus on the dorsal side. We made a diagnosis of an LVP due to IE and performed mitral valve replacement and patch plasty of the mitral annulus. Thus, P. mirabilis can cause bloodstream infections and lead to IE, which may result in LVPs. .

An activating and inhibitory signal from an inhibitory receptor LMIR3/CLM-1: LMIR3 augments lipopolysaccharide response through association with FcRgamma in mast cells.

Leukocyte mono-Ig-like receptor 3 (LMIR3) is an inhibitory receptor mainly expressed in myeloid cells. Coengagement of Fc epsilonRI and LMIR3 impaired cytokine production in bone marrow-derived mast cells (BMMCs) induced by Fc epsilonRI crosslinking alone. Mouse LMIR3 possesses five cytoplasmic tyrosine residues (Y241, Y276, Y289, Y303, Y325), among which Y241 and Y289 (Y241/289) or Y325 fit the consensus sequence of ITIM or immunotyrosine-based switch motif (ITSM), respectively. The inhibitory effect was abolished by the replacement of Y325 in addition to Y241/289 with phenylalanine (Y241/189/325/F) in accordance with the potential of Y241/289/325 to cooperatively recruit Src homology region 2 domain-containing phosphatase 1 (SHP)-1 or SHP-2. Intriguingly, LMIR3 crosslinking alone induced cytokine production in BMMCs expressing LMIR3 (Y241/276/289/303/325F) mutant as well as LMIR3 (Y241/289/325F). Moreover, coimmunoprecipitation experiments revealed that LMIR3 associated with ITAM-containing FcRgamma. Analysis of FcRgamma-deficient BMMCs demonstrated that both Y276/303 and FcRgamma played a critical role in the activating function of this inhibitory receptor. Importantly, LMIR3 crosslinking enhanced cytokine production of BMMCs stimulated by LPS, while suppressing production stimulated by other TLR agonists or stem cell factor. Thus, an inhibitory receptor LMIR3 has a unique property to associate with FcRgamma and thereby functions as an activating receptor in concert with TLR4 stimulation.

Ectopically expressed PIR-B on T cells constitutively binds to MHC class I and attenuates T helper type 1 responses.

Activated mature T cells induce various inhibitory receptors implicated in maintaining peripheral tolerance in response to the trans-acting ligands. Interestingly, paired Ig-like receptor (PIR)-B, an inhibitory MHC class I receptor on B cells and myeloid cells, could be involved in regulating early T cell development because epitope for PIR is detected on pre-thymic T/NK progenitors but not on thymocytes or mature T cells. We hypothesized that PIR-B is not only a regulator for T cell development but is also detrimental if expressed on mature T cells. Here we demonstrated, using PIR-B-deficient fetuses, that PIR-B is indeed expressed on the T cell progenitors but failed to identify its distinctive roles in the development. Forced expression of PIR-B in thymocytes and mature T cells also resulted in no abnormalities in development. However, upon antigenic or allogeneic stimulation, peripheral T cells with the ectopic PIR-B showed reduced T(h) type 1 responses due to the suppression of proximal TCR signaling by constitutive binding of PIR-B to MHC class I on the same cell surface. Our findings suggest that T cell expression of PIR-B with the cis-interacting MHC class I is strictly prohibited in periphery so as to secure prompt immune responses.

Persistence of constrictive pattern despite improvement in symptoms after the waffle procedure: A case report of constrictive pericarditis.

Constrictive pericarditis (CP) is an uncommon disease characterized by clinical signs of right-sided heart failure subsequent to loss of pericardial compliance. Although pericardiectomy is the accepted treatment for improving cardiac hemodynamics in CP, some patients fail to improve after pericardiectomy. We herein report a case of CP that showed some physical and hemodynamic features with a constrictive pattern that persisted despite the improvement in heart failure symptoms after pericardiectomy. A 61-year-old man was diagnosed with CP 7 months after the onset of symptoms of shortness of breath and edema in the legs. The waffle procedure was performed using an ultrasonic scalpel. Post-operative cardiac catheterization demonstrated a dip-and-plateau pattern in both right ventricular (RV) and left ventricular (LV) pressures, but the RV and LV end-diastolic pressures improved. Moreover, Doppler echocardiography showed an improvement in the change in mitral and tricuspid early velocities with respiration. Decrease in intraoperative right atrial pressure and respiratory variability in LV and RV inflow on echocardiography are important predictors of improvement in post-operative heart failure symptoms. Learning objective: Decrease in intraoperative right atrial pressure and respiratory variability in left ventricular and right ventricular inflow on post-operative echocardiography are important predictors of improvement in heart failure symptoms even if some hemodynamic features characterizing constrictive pericarditis (dip and plateau pattern, Friedreich's sign) persist.>.

A Case of Superior Mesenteric Venous Thrombosis Managed by Thrombectomy without Bowel Resection.

We present a case of superior mesenteric venous thrombosis (SMVT) treated successfully with thrombectomy without bowel resection. A 73-year-old female was referred to our hospital with complaints of stomach ache. The patient was diagnosed with SMVT with impending bowel necrosis and underwent an emergency operation, after computed tomography (CT) revealed a thrombus in the superior mesenteric vein (SMV) extending to the splenic vein, ascites, and extremely edematous intestines. The intestines were not necrotic though highly congested. To avoid massive bowel resection, aggressive thrombectomy was performed. Postoperative CT confirmed resolved SMV and improved bowel edema. Prompt thrombectomy should be considered in such cases.

Left Subclavian-Bilateral External Carotid Artery Bypass for Symptomatic Carotid Artery Dissection Secondary to Open Repair of Type A Aortic Dissection.

Symptomatic carotid dissection, secondary to surgical repair of Stanford type A acute aortic dissection (AAD), requires prompt intervention. A 56-year-old man who underwent total arch replacement with frozen elephant trunk for AAD presented with left hemiplegia and unilateral spatial neglect 16 h after the surgery. Cerebral computed tomography (CT) revealed no fresh lesions, and CT angiography showed severe bilateral carotid dissection. The patient's neurological symptoms improved soon after left subclavian-bilateral external carotid artery bypass to correct symptomatic severe right cerebral ischemia. Therefore, this technique can be a good option for symptomatic carotid dissection in selected patients.

Eco-Friendly Highly Sensitive Transducers Based on a New KNN-NTK-FM Lead-Free Piezoelectric Ceramic for High-Frequency Biomedical Ultrasonic Imaging Applications.

High-frequency ultrasonic imaging with improved spatial resolution has gained increasing attention in the field of biomedical imaging. Sensitivity of transducers plays a pivotal role in determining ultrasonic image quality. Conventional ultrasonic transducers are mostly made from lead-based piezoelectric materials that may be harmful to the human body and the environment. In this study, a new (K,Na)NbO3-KTiNbO5-BaZrO3-Fe2O3-MgO (KNN-NTK-FM) lead-free piezoelectric ceramic was utilized in developing eco-friendly transducers for high-frequency biomedical ultrasonic imaging applications. A needle transducer with a small active aperture size of 0.45 × 0.55 mm2 was designed and evaluated. The fabricated transducer exhibits great performance with a high center frequency (52.6 MHz), a good electromechanical coupling (keff ∼ 0.45), a large bandwidth (64.4% at -6 dB), and a very low two-way insertion loss (10.1 dB). Such high sensitivity is superior to those transducers based on other lead-free piezoelectric materials and can even be comparable to the lead-based ones. Imaging performance of the KNN-NTK-FM needle transducer was analyzed by imaging a wire phantom and an agar tissue-mimicking phantom. Imaging capabilities of the transducer were further demonstrated by ex vivo imaging studies on a porcine eyeball and a rabbit aorta. The results suggest that the KNN-NTK-FM piezoceramic has many attractive properties over other lead-free piezoelectric materials in developing eco-friendly highly sensitive transducers for high-frequency biomedical ultrasonic imaging applications.

Left Ventricular Blood Flow Dynamics In Aortic Stenosis Before And After Aortic Valve Replacement.

Surgical intervention for aortic valve stenosis (AS) has been established; however its diagnosis based on echocardiographic assessment is still limited by aortic valvular velocity, aortic valvular pressure gradients, and color Doppler imaging. Echo-dynamography (EDG) is a method to determine intracardiac flow dynamics, such as two-dimensional blood flow velocity, vortex, and dynamic pressure. These flow dynamics may be influenced by left ventricular (LV) wall motion and the resistance in LV outflow caused by AS. The objective of the present study was to assess the changes and differences in LV vortices and vorticity before and after AS surgery. Five patients who underwent aortic valve replacement surgery for AS and five control patients were included. Besides routine echocardiographic measurement, EDG was applied to determine the two-dimensional blood flow vector and vorticity. The LV vortex flow in the isovolumetric contraction phase had multiple formations in preoperative cases. The clockwise vortex was found in all cases postoperatively; the vortex formation showed no significant difference between postoperative and normal control groups. EDG may serve important information on LV flow dynamics, non-invasively.

Potential establishment of lung metastatic xenograft model of androgen receptor-positive and androgen-independent prostate cancer (C4-2B).

OBJECTIVE: To establish a mouse xenograft model of metastatic prostate cancer (PCa) and investigate the relationship between metastasis and circulating tumor cells. METHODS: Flow cytometry (FACS) was used to detect suitable PCa cells and markers for detecting circulating tumor cells in vivo. We orthotopically injected androgen receptor-positive and androgen-independent C4-2B PCa cells into 12 severe combined immunodeficiency (SCID) mouse prostates, including 1 vehicle control. We measured the serum prostate-specific antigen levels biweekly after tumor inoculation. Circulating tumor cells (CTCs) were measured qualitatively by fluorescent microscopy immediately after the mice were sacrificed. The mouse prostates and lungs were examined for tumor formation using immunohistochemistry because we found no apparent metastasis, except in the lung. RESULTS: FACS analyses in vitro identified the marker, prostate-specific membrane antigen, and C4-2B cells to be appropriate for additional in vivo study. We confirmed that the serum prostate-specific antigen increase was dependent on time and prostate tumor weight in mice. Of the 11 mice, 6 could be used as the mouse PCa xenograft model. Fluorescent microscopy detected CTCs in the peripheral blood in 5 of the 6 mice constituting the PCa model. Human prostate-specific antigen expression was detected by immunohistochemistry in the prostates of all the mice and in the lung of 2 of the 6 mice, suggesting 2 mice with lung metastasis. CONCLUSION: We have shown the potential establishment of a mouse lung metastatic xenograft model of androgen receptor-positive and androgen-independent C4-2B PCa tumor. However, the present model requires improvement to be a more reproducible, accurate and complete experimental model. Additional study is necessary to verify the relationship between metastasis and CTCs.

Detection of tumor markers in prostate cancer and comparison of sensitivity between real time and nested PCR.

The objective of this study is to investigate and compare the sensitivity in conventional PCR, quantitative real time PCR, nested PCR and western blots for detection of prostate cancer tumor markers using prostate cancer (PCa) cells. We performed conventional PCR, quantitative real time PCR, nested PCR, and western blots using 5 kinds of PCa cells. Prostate specific antigen (PSA), prostate specific membrane antigen (PSMA), and androgen receptor (AR) were compared for their detection sensitivity by real time PCR and nested PCR. In real time PCR, there was a significant correlation between cell number and the RNA concentration obtained (R(2)=0.9944) for PSA, PSMA, and AR. We found it possible to detect these markers from a single LNCaP cell in both real time and nested PCR. By comparison, nested PCR reached a linear curve in fewer PCR cycles than real time PCR, suggesting that nested PCR may offer PCR results more quickly than real time PCR. In conclusion, nested PCR may offer tumor maker detection in PCa cells more quickly (with fewer PCR cycles) with the same high sensitivity as real time PCR. Further study is necessary to establish and evaluate the best tool for PCa tumor marker detection.

Analysis of mouse LMIR5/CLM-7 as an activating receptor: differential regulation of LMIR5/CLM-7 in mouse versus human cells.

We have analyzed leukocyte mono-Ig-like receptor 5 (LMIR5) as an activating receptor among paired LMIRs. Mouse LMIR5 (mLMIR5) is expressed in myeloid cells such as mast cells, granulocytes, macrophages, and dendritic cells. Cross-linking of transduced mLMIR5 in bone marrow-derived mast cells (BMMCs) caused activation events, including cytokine production, cell survival, degranulation, and adhesion to the extracellular matrix. mLMIR5 associated with DAP12 and to a lesser extent with DAP10, and mLMIR5-mediated functions of BMMCs were strongly inhibited by DAP12 deficiency. Importantly, cross-linking of endogenous mLMIR5 induced Syk-dependent activation of fetal liver-derived mast cells. Unlike mLMIR5, cross-linking of human LMIR5 (hLMIR5) induced cytokine production of BMMCs even in the absence of both DAP12 and DAP10, suggesting the existence of unidentified adaptors. Interestingly, hLMIR5 possessed a tyrosine residue (Y188) in the cytoplasmic region. Signaling via Y188 phosphorylation played a predominant role in hLMIR5-mediated cytokine production in DAP12-deficient, but not wild-type BMMCs. In addition, experiments using DAP10/DAP12 double-deficient BMMCs suggested the existence of Y188 phoshorylation-dependent and -independent signals from unidentified adaptors. Collectively, although both mouse and human LMIR5 play activatory roles in innate immunity cells, the functions of LMIR5 were differentially regulated in mouse versus human cells.

Functional analysis of activating receptor LMIR4 as a counterpart of inhibitory receptor LMIR3.

The leukocyte mono-Ig-like receptor (LMIR) belongs to a new family of paired immunoreceptors. In this study, we analyzed activating receptor LMIR4/CLM-5 as a counterpart of inhibitory receptor LMIR3/CLM-1. LMIR4 is expressed in myeloid cells, including granulocytes, macrophages, and mast cells, whereas LMIR3 is more broadly expressed. The association of LMIR4 with Fc receptor-gamma among immunoreceptor tyrosine-based activation motif-bearing molecules was indispensable for LMIR4-mediated functions of bone marrow-derived mast cells, but dispensable for its surface expression. Cross-linking of LMIR4 led to Lyn- and Syk-dependent activation of bone marrow-derived mast cells, resulting in cytokine production and degranulation, whereas that of LMIR3 did not. The triggering of LMIR4 and TLR4 synergistically caused robust cytokine production in accordance with enhanced activation of ERK, whereas the co-ligation of LMIR4 and LMIR3 dramatically abrogated cytokine production. Notably, intraperitoneal administration of lipopolysaccharide strikingly up-regulated LMIR3 and down-regulated LMIR4, whereas that of granulocyte colony-stimulating factor up-regulated both LMIR3 and LMIR4 in granulocytes. Cross-linking of LMIR4 in bone marrow granulocytes also resulted in their activation, which was enhanced by lipopolysaccharide. Collectively, these results suggest that the innate immune system is at least in part regulated by the qualitative and quantitative balance of the paired receptors LMIR3 and LMIR4.