TSCOT+ thymic epithelial cell-mediated sensitive CD4 tolerance by direct presentation.

Although much effort has been directed at dissecting the mechanisms of central tolerance, the role of thymic stromal cells remains elusive. In order to further characterize this event, we developed a mouse model restricting LacZ to thymic stromal cotransporter (TSCOT)-expressing thymic stromal cells (TDLacZ). The thymus of this mouse contains approximately 4,300 TSCOT+ cells, each expressing several thousand molecules of the LacZ antigen. TSCOT+ cells express the cortical marker CDR1, CD40, CD80, CD54, and major histocompatibility complex class II (MHCII). When examining endogenous responses directed against LacZ, we observed significant tolerance. This was evidenced in a diverse T cell repertoire as measured by both a CD4 T cell proliferation assay and an antigen-specific antibody isotype analysis. This tolerance process was at least partially independent of Autoimmune Regulatory Element gene expression. When TDLacZ mice were crossed to a novel CD4 T cell receptor (TCR) transgenic reactive against LacZ (BgII), there was a complete deletion of double-positive thymocytes. Fetal thymic reaggregate culture of CD45- and UEA-depleted thymic stromal cells from TDLacZ and sorted TCR-bearing thymocytes excluded the possibility of cross presentation by thymic dendritic cells and medullary epithelial cells for the deletion. Overall, these results demonstrate that the introduction of a neoantigen into TSCOT-expressing cells can efficiently establish complete tolerance and suggest a possible application for the deletion of antigen-specific T cells by antigen introduction into TSCOT+ cells.

Changes in Na(+)-K(+)-Cl(-) cotransporter immunoreactivity in the gerbil hippocampus following transient ischemia.

We examined alterations in Na(+)-K(+)-Cl(-) cotransporter 1 (NKCC1) immunoreactivity following ischemia. Twelve hours after ischemia, NKCC1 immunoreactivity in the CA1 region and in the hilar region was significantly diminished. Twenty-four hours after ischemia, NKCC1 immunoreactivity was intensified in these hippocampal regions as well as CA2-3. Two days after ischemia, NKCC1 immunoreactivity in the CA1 and the hilar neurons had disappeared, although in the CA2-3 and the granule cell layer NKCC1 immunoreactivities had recovered to the sham level. This finding suggests that NKCC1 may play an important role in the ischemic neuronal injury induced by excitotoxicity as well as neuronal edema.

The impact of hepatitis B on heart transplantation: 19 years of national experience in Korea.

BACKGROUND: Hepatitis B virus (HBV) infection is endemic in Korea. With an increasing number of heart transplantation, problems associated with hepatitis B reactivation are becoming an important issue. We aimed to evaluate the functional significance of HBV infection on outcomes of heart transplantation. MATERIAL AND METHODS: We reviewed all medical records of overall national heart transplantation recipients and donors who had HBV hepatitis at the time of the transplantation, from March 1994 to May 2013. We investigated the HBV serology status, HBV-DNA level of donors and recipients, liver function test, immunosuppressive agent and antiviral agent prescription, and hepatitis morbidity and mortality. RESULTS: 1) There were 12 HBsAg (+) recipients and 6 HBsAg (+) donors. Median duration of follow-up was 1715 days (minimum 162 days to maximum 6553 days). 2) Nine HBsAg (+) recipients (75%), who continued antiviral treatment, have survived without any hepatic event. Reactivation of HBV developed in 3 recipients at a median duration of 238 days after transplantation. They died of fulminant hepatitis despite antiviral rescue therapy. 3) In contrast, 6 recipients with immunity to HBV before the transplantation, who had received heart from HBV (+) donors, have survived without any liver-related event. CONCLUSIONS: HBV (+) recipients have perioperative results and long-term survival rates comparable to HBV (-) recipients. However, absence or cessation of antiviral prophylaxis indiscriminately brought reactivation of HBV, which rapidly progressed to hepatic failure and death. In contrast, HBV (+) hearts transplanted to HBV-immune recipients were maintained without hepatitis reactivation. Nineteen years of national experience strongly suggests that long-term antiviral prophylaxis is necessary for HBV (+) recipients.

Successful Medical Treatment of Prosthetic Mitral Valve Endocarditis Caused by Brucella abortus.

Although Brucella endocarditis is a rare complication of human brucellosis, it is the main cause of the mortality in this disease. Traditionally, the therapeutic approach to endocarditis caused by Brucella species requires a combination of antimicrobial therapy and valve replacement surgery. In the literature, only a few cases of mitral prosthetic valve endocarditis caused by Brucella species have been successfully treated without reoperation. We present a case of a 42-year-old man with a prosthetic mitral valve infected by Brucella abortus who was cured solely by medical treatment.

A case of cardiac beriberi: a forgotten but memorable disease.

Thiamine (vitamin B1) serves as an important cofactor in body metabolism and energy production. It is related with the biosynthesis of neurotransmitters and the production of substances used in defense against oxidant stress. Thus, a lack of thiamine affects several organ systems, in particular the cardiovascular and nervous system. The cardiac insufficiency caused by thiamine deficiency is known as cardiac beriberi, with this condition resulting from unbalanced nutrition and chronic excessive alcohol intake. Given that the disease is now very rare in developed nations such as Korea, it is frequently missed by cardiologists, with potentially fatal consequences. Herein, we present a case study in order to draw attention to cardiac beriberi. We believe that this case will be helpful for young cardiologists, reminding them of the importance of this forgotten but memorable disease.

Organized prosthetic tricuspid valve thrombosis treated successfully with medical treatment.

Prosthetic valve thrombosis (PVT) can be a life-threatening complication that requires immediate treatment. We present a case of 57-year-old woman with tricuspid PVT who was definitely diagnosed by multi-detector-row computed tomography limited with echocardiography. The patient was treated successfully with an alternative approach using low molecular weight heparin bridging therapy followed by intensifying anticoagulation alone.

Primary malignant pericardial mesothelioma presenting as acute pericarditis.

We report on a 21-year-old man with fever, dyspnea, and pleuritic chest pain. An electrocardiography showed ST elevation in multiple lead and thoracic echocardiography revealed moderate pericardial effusion. He was initially diagnosed with acute pericarditis, and treated with nonsteroidal anti-inflammatory drugs and colchicines with clinical and laboratory improvement. After 1 month of medication, his symptoms recurred. An echocardiography showed constrictive physiology and the patient was treated with steroid on the top of current medication. The patient had been well for 7 months until dyspnea and edema developed, when an echocardiography showed marked increased pericardial thickness and constriction. Pericardial biopsy was performed and primary malignant pericardial mesothelioma was diagnosed. Malignancy should be considered in the differential diagnosis of recurrent pericarditis.

Total Occlusion of Right Main Pulmonary Artery in a Patient with Takayasu's Arteritis and Severe Pulmonary Hypertension.

Takayasu's arteritis is a chronic inflammatory disorder that mainly involves medium to large sized arteries. Although pulmonary artery involvement is reported with a prevalence of about 10% to 50%, its clinical significance is underestimated. We report here one case of Takayasu's arteritis complicated by severe pulmonary hypertension due to right main pulmonary artery total occlusion.