Environmental chemical-induced bone marrow B cell apoptosis: Death receptor-independent activation of a caspase-3 to caspase-8 pathway

ABSTRACT Programmed cell death is a critical process in B lymphocyte development. Premature apoptosis in developing B cells could affect the repertoire and number of mature B cells produced. Of particular concern is the ability of environmentally ubiquitous polycyclic aromatic hydrocarbons (PAH) to induce B cell apoptosis within the bone marrow microenvironment in a clonally nonspecific way. Here, models of bone marrow B cell development were used to assess the role of the "extrinsic" apoptosis pathway in PAH-induced apoptosis and to compare PAH-induced apoptosis with that induced during clonal deletion. A

Differences in Clinical Features According to Boryoung and Karp Genotypes of Orientia tsutsugamushi

Scrub typhus is an infectious disease caused by Orientia tsutsugamushi. The differences in virulence of O. tsutsugamushi prototypes in humans are still unknown. We investigated whether there are any differences in the clinical features of the Boryoung and Karp genotypes.Patients infected with O. tsutsugamushi, as Boryoung and Karp clusters, who had visited 6 different hospitals in southwestern Korea were prospectively compared for clinical features, complications, laboratory parameters, and treatment responses. Infected patients in the Boryoung cluster had significantly more generalized weakness, eschars, skin rashes, conjunctival injection, high albumin levels, and greater ESR and fibrinogen levels compared to the Karp cluster. The treatment response to current antibiotics was significantly slower in the Karp cluster as compared to the Boryoung cluster.The frequency of occurrence of eschars and rashes may depend on the genotype of O. tsutsugamushi

Validation of the Korean Version of the Lewy Body Composite Risk Score (K-LBCRS)

The Lewy body composite risk score (LBCRS) is a useful clinical screening tool to help determine whether the dementia is related to Lewy body pathology. The purpose of this study is to verify reliability, validity, and diagnostic usefulness of Korean version of LBCRS (K-LBCRS). CDR-sum of boxes, Mini-Mental State Examination, and standardized scales related to cognition, mood, behavior, and motor function were administered to a total of 107 subjects, including 30 dementia with Lewy bodies (DLB), 54 Alzheimer's disease (AD), and 23 cognitively normal elderly people and their collateral informants. Internal consistency of the K-LBCRS was good with Cronbach's alpha of 0.85, and concurrent validity was also satisfactory, with K-LBCRS correlating highly with CDR-SB and other scales. The test-retest reliability was very high with a Pearson correlation coefficient of 0.97. The mean scores of K-LBCRS were significantly different among three groups, with DLB (6.2 +/- 2.4), AD (1.4 +/- 1.3), and controls (0.3 +/- 0.6). We identified a cut-off score of 3 as best to differentiate between DLB and AD, having AUC of 0.97 (95% CI 0.94-1.00), sensitivity 97%, specificity 83%, positive predictive value 76%, negative predictive value 98%, which is the same score suggested in the original study. This study shows K-LBCRS as a new useful screening tool for Korean DLB patients in clinical settings

Endotoxin Contamination in Commercially Available Pokeweed Mitogen Contributes to the Activation of Murine Macrophages and Human Dendritic Cell Maturation

Commercially available pokeweed mitogen (PWM) has been reported to activate macrophages, leading to production of proinflammatory cytokines and nitric oxide (NO). However, we found that polymyxin B (PMB), a specific inhibitor of endotoxin activity, inhibited the PWM-induced expression of proinflammatory cytokines and NO and the activation of Toll-like receptor 4 (TLR4). A kinetic-turbidimetric Limulus amebocyte lysate assay demonstrated that commercial PWM contained substantial endotoxin, over 10(4) endotoxin units/mg of the PWM. A PWM repurified by PMB-coupled beads no longer induced the expression of proinflammatory cytokines, TLR4 activation, or dendritic cell maturation. However, the repurified PWM remained able to induce proliferation of human lymphocytes, which is a representative characteristic of PWM. These results suggest that commercial PWM might be contaminated with a large amount of endotoxin, resulting in the attribution of misleading immunological properties to PWM

Leicoteipoic acid partially contributes the inflammatory response to E. faecalis

Enterococcus faecalis, a pathogenic gram-positive bacterium, is closely related to refractory apical periodontitis. Because lipoteichoic acid (LTA) is considered a major virulence factor of gram-positive bacteria, in the present study, highly pure LTA from E. faecalis was prepared, and its ability to stimulate murine macrophages was investigated in comparison with those of the killed whole cells. Upon exposure to E. faecalis LTA, RAW 264.7 (a murine macrophage cell line) produced a significantly (p < 0.05) high level of tumor necrosis factor-α (TNF-α) and nitric oxide (NO) in a concentration-dependent manner. It is to note that the LTA was able to stimulate Toll-like receptor 2 (TLR2) but not TLR4. Concomitantly, LTA enhanced the DNA-binding activity of a transcription factor, nuclear factor-kappa B (NF-κB), which plays an important role in the transcriptional activation of genes encoding inflammatory mediators. In contrast, heat-killed E. faecalis stimulated both TLR2 and TLR4, whereas the killed E. faecalis whole cells induced significant (p < 0.05) levels of TNF-α and NO in RAW 264.7 cells as their LTA did. These results suggest that LTA partially contributes to E. faecalis–induced inflammatory responses

Anti-Inflammatory Potential of Newly Synthesized 4-[(Butylsulfinyl)methyl]-1,2-benzenediol in Lipopolysaccharide-Stimulated BV2 Microglia

In this study, we investigated the anti-inflammatory effects of newly synthesized 4-[(butylsulfinyl)methyl]-1,2-benzenediol (SMBD) in lipopolysaccharide (LPS)-stimulated BV2 microglia and the subsequent signaling events. Following stimulation with LPS, elevated production of nitric oxide (NO) and prostaglandin E2 (PGE2) was detected in BV2 cells; however, SMBD pretreatment inhibited the production of NO and PGE2 through suppressing gene expression of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2), respectively, at non-toxic concentrations. LPS-stimulated gene expression and production of interleukin (IL)-1β and tumor necrosis factor (TNF)-α were also significantly reduced by SMBD. The anti-inflammatory effects of SMBD were associated with suppression of LPS-induced nuclear translocation of nuclear factor-kappa B (NF-κB), and phosphorylation of mitogen-activated protein kinases (MAPKs) and Akt, a phosphatidylinositol 3-kinase (PI3K) downstream effector. Therefore, the present results demonstrate that SMBD down-regulates inflammatory gene expression by inhibiting the activation of NF-κB through interference with the activation of MAPKs and PI3K/Akt signaling. Taken together, our data suggest that SMBD may have potential to be developed into an effective anti-inflammatory agent