Activation of the classical complement pathway by Bacillus anthracis is the primary mechanism for spore phagocytosis and involves the spore surface protein BclA

Interactions between spores of Bacillus anthracis and macrophages are critical for the development of anthrax infections, as spores are thought to use macrophages as vehicles to disseminate in the host. In this study, we report a novel mechanism for phagocytosis of B. anthracis spores. Murine macrophage-like cell line RAW264.7, bone marrow-derived macrophages, and primary peritoneal macrophages from mice were used. The results indicated that activation of the classical complement pathway (CCP) was a primary mechanism for spore phagocytosis. Phagocytosis was significantly reduced in the absence of C1q or C3. C3 fragments were found deposited on the spore surface, and the deposition was dependent on C1q and Ca(2+). C1q recruitment to the spore surface was mediated by the spore surface protein BclA, as recombinant BclA bound directly and specifically to C1q and inhibited C1q binding to spores in a dose-dependent manner. C1q binding to spores lacking BclA (ΔbclA) was also significantly reduced compared with wild-type spores. In addition, deposition of both C3 and C4 as well as phagocytosis of spores were significantly reduced when BclA was absent, but were not reduced in the absence of IgG, suggesting that BclA, but not IgG, is important in these processes. Taken together, these results support a model in which spores actively engage CCP primarily through BclA interaction with C1q, leading to CCP activation and opsonophagocytosis of spores in an IgG-independent manner. These findings are likely to have significant implications on B. anthracis pathogenesis and microbial manipulation of complement.     

Oligomeric Aβ-Induced Microglial Activation is Possibly Mediated by NADPH Oxidase

Recent studies have shown that oligomeric amyloid-β (oAβ) peptide can potentially activate microglia in addition to inducing more potent neurotoxicity compared with fibrillar Aβ (fAβ); however, its mechanisms of action remain unclear. This study was designed to investigate the possible mechanisms involved in the microglial activation induced by oAβ in BV-2 microglial cells. The results showed that oAβ induced activated properties of microglia, including higher proliferative capacity as well as increased production of reactive oxygen species, nitric oxide (NO), tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β). NADPH oxidase inhibitors [diphenylene iodonium (DPI) and apocynin (4-hydroxy-3-methoxy-acetophenone)] prevented the microglial activation induced by oAβ, suggesting that NADPH oxidase activation was involved in microglial activation. In addition, TNF-α and IL-1β, which are massively released by activated microglia, significantly induced the activation of microglia, thereby resulting in the production of NO and proliferation of microglia, respectively. These effects could be inhibited by diphenylene iodonium and apocynin, indicating a self-cycle regulated by NADPH oxidase in microglial activation in response to oAβ. In conclusion, microglial activation induced by oAβ is possibly mediated by NADPH oxidase, suggesting that oAβ, which is normally considered a neurotoxin, may also lead to indirect neuronal damage through the pro-inflammation activation of microglia in Alzheimer’s disease and that NADPH oxidase could be a potential target to prevent oAβ-induced inflammatory neurodegeneration.     

抗甲3型流感病毒卵黄抗体的研制

制备抗H3N2型流感病毒特异性鸡卵黄免疫球蛋白（IgY),防治同型流感病毒引起的流感,制备H3N2型流感病毒,通过两种途径免疫母鸡,以水稀释-硫酸铵沉淀及离子交换层析法提纯,并进行理化性质分析和动物效力试验。两种途径免疫均可使母鸡产生特异性IgY,其中以静脉为主的混合免疫法效果较好,提纯后纯度可达90%以上,通过被动免疫可使小鼠对同型流感病毒的攻击产生保护作用。结果表明,已成功地制备出高效价的H3N2型流感病毒特异性IgY。     

多巴胺对PC12细胞的双重影响

本实验运用PC12细胞,研究不同浓度多巴胺（dopamine,DA)对细胞的影响,同时利用兼具促进多巴胺释放和抑制多巴胺摄取双重作用的安排它命（amphetamine,AMP)观察胞内外多巴胺对细胞的不同作用。结果显示;胞外高浓度DA能引起细胞抗氧化能力下降,胞内游离Ca^2 浓度上升。细胞存活率大幅度降低,部分细胞出现凋亡;低浓度DA对细胞存活率无明显影响,而使细胞抗氧化能力有一定提高,长时间安非它命单独作用也可引起细胞存活率下降,并伴随胞内GSH水平降低;安非它命与多巴胺共同作用在一定程度上可导致细胞内抗氧化物质水平低于多巴胺单独作用,表明细胞内一定浓度DA可以维持或提高细胞抗氧化物质水平。结果提示,脑内同样存在的多巴胺神经元对DA重摄取功能下降,胞外氧化应激增强,可能是引起脑内多巴胺神经元退行性病变的重要原因之一。     

128-Slice Acceletated-Pitch Dual Energy CT Angiography of the Head and Neck: Comparison of Different Low Contrast Medium Volumes

Background

Our study aims to evaluate the image quality and feasibility of 128-slice dual-energy CTA (DE-CTA) for supra-aortic arteries using reduced amounts of contrast medium (CM).

Methods

A prospective study was performed in 54 patients receiving CTA of the head and neck with a 128-slice dual-source CT system. Patients were randomized into two groups with a volume of either 40 mL of CM (Group I) or 50 mL of CM (Group II). Arterial and venous enhancements were recorded for quantitative assessment. Qualitative assessments for images without bone removal (BR) were based on a) the visualization of the circle of Willis and b) streak artifacts due to residual CM in the subclavian or internal jugular veins ipsilateral to injection of CM. Qualitative assessment of dual-energy images using BR was based on the presence of bone remnants and vessel integrity. Quantitative data was compared using the Student t test. The χ² test was used for the qualitative measurements of streak artifacts in veins while the Mann-Whitney U test was used for the qualitative measurements of images with BR.

Results

Arterial and venous attenuation was significantly higher in Group II (P=0.000). Image quality regarding the circle of Willis was excellent in both groups (3.90±0.30 for Group I and 4.00±0 for Group II) . Imaging of the internal jugular veins was scored higher in Group I (1.87±0.72) compared with Group II (1.48±0.51) (P=0.021). Within Group I using BR, mean scores for bone remnants did not differ significantly (P>0.05) but mean scores of vessel integrity (P<0.05) did.

Conclusions

Contrast-enhanced head and neck CTA is feasible using a scan protocol with low amounts of contrast medium (40 mL) on a 128-slice dual-energy CTA. The 40-mL protocol provides satisfactory image quality before and after dual-energy bone-removal post-processing.     

Altered Pattern of Spontaneous Brain Activity in the Patients with End-Stage Renal Disease: A Resting-State Functional MRI Study with Regional Homogeneity Analysis

Purpose

To investigate the pattern of spontaneous neural activity in patients with end-stage renal disease (ESRD) with and without neurocognitive dysfunction using resting-state functional magnetic resonance imaging (rs-fMRI) with a regional homogeneity (ReHo) algorithm.

Materials and Methods

rs-fMRI data were acquired in 36 ESRD patients (minimal nephro-encephalopathy [MNE], n = 19, 13 male, 37±12.07 years; non-nephro-encephalopathy [non-NE], n = 17, 11 male, 38±12.13 years) and 20 healthy controls (13 male, 7 female, 36±10.27 years). Neuropsychological (number connection test type A [NCT-A], digit symbol test [DST]) and laboratory tests were performed in all patients. The Kendall''s coefficient of concordance (KCC) was used to measure the regional homogeneity for each subject. The regional homogeneity maps were compared using ANOVA tests among MNE, non-NE, and healthy control groups and post hoc t -tests between each pair in a voxel-wise way. A multiple regression analysis was performed to evaluate the relationships between ReHo index and NCT-A, DST scores, serum creatinine and urea levels, disease and dialysis duration.

Results

Compared with healthy controls, both MNE and non-NE patients showed decreased ReHo in the multiple areas of bilateral frontal, parietal and temporal lobes. Compared with the non-NE, MNE patients showed decreased ReHo in the right inferior parietal lobe (IPL), medial frontal cortex (MFC) and left precuneus (PCu). The NCT-A scores and serum urea levels of ESRD patients negatively correlated with ReHo values in the frontal and parietal lobes, while DST scores positively correlated with ReHo values in the bilateral PCC/precuneus, MFC and inferior parietal lobe (IPL) (all P<0.05, AlphaSim corrected). No significant correlations were found between any regional ReHo values and disease duration, dialysis duration and serum creatinine values in ESRD patients (all P>0.05, AlphaSim corrected).

Conclusion

Diffused decreased ReHo values were found in both MNE and non-NE patients. The progressively decreased ReHo in the default mode network (DMN), frontal and parietal lobes might be trait-related in MNE. The ReHo analysis may be potentially valuable for elucidating neurocognitive abnormalities of ESRD patients and detecting the development from non-NE to MNE.     

Testicular protein Spag5 has similarity to mitotic spindle protein Deepest and binds outer dense fiber protein Odf1

Outer dense fibers (ODF) and the fibrous sheath (FS) are major cytoskeletal structures in the mammalian sperm tail. The molecular mechanisms underlying their morphogenesis along the axoneme or their function are poorly understood. Recently, we reported the cloning and characterization of Odf2, a major ODF protein, and Spag4, an axoneme-binding protein, by virtue of their strong interaction with Odf1, the 27 kDa major ODF protein. We proposed a crucial role for leucine zippers in molecular interactions during sperm tail morphogenesis. Here we report the cloning and characterization of a novel gene, Spag5, which encodes a 200 kDa testicular protein that interacts strongly with Odf1. Spag5 is transcribed and translated in pachytene spermatocytes and spermatids. It bears 73% similarity with the mitotic spindle protein Deepest of unknown function. We identified two putative leucine zippers in the C-terminal part of the Spag5 protein, the downstream one of which is involved in interaction with Odf1. Interestingly, these motifs are present in Deepest. These results highlight the importance of the leucine zipper in sperm tail protein interactions. Mol. Reprod. Dev. 59: 410-416, 2001.     

同型半胱氨酸对大鼠血管平滑肌细胞增殖的作用

血中同型半胱氨酸（ｈｏｍｏｃｙｓｔｅｉｎｅ,ＨＣＹ）浓度的升高已成为动脉粥样硬化发生的一个独立危险因子．为进一步阐明ＨＣＹ促进血管平滑肌细胞（ｖａｓｃｕｌａｒｓｍｏｏｔｈｍｕｓｃｌｅｃｅｌｓ,ＶＳＭＣｓ）增殖,从而引起动脉粥样硬化发生的机理．本实验采用细胞计数、３Ｈ－ＴｄＲ参入、细胞周期分析、Ｎｏｒｔｈｅｒｎ杂交方法证明,一定剂量的ＨＣＹ可促进离体培养的ＷＫＹ大鼠血管平滑肌细胞增殖,使其ＤＮＡ合成增加,细胞周期中Ｓ期细胞所占比例增加４３％,并促进ｃ－ｍｙｃ与ｃ－ｆｏｓ原癌基因ｍＲＮＡ表达增加．提示ＨＣＹ可能通过促进ＶＳＭＣｓ增殖而诱发动脉粥样硬化     

Effect of feeding frequency on growth, feed utilization, and size variation of juvenile gibel carp (Carassius auratus gibelio)

Juvenile (3.0 ± 0.2 g) gibel carp (Carassius auratus gibelio) were fed to satiation for 8 weeks to investigate the effect of feeding frequency on growth, feed utilization and size variation. Five feeding frequencies were tested: two meals per day (M2), three meals per day (M3), four meals per day (M4), 12 meals per day (M12) and 24 meals per day (M24). The results showed that daily food intake increased significantly with the increase in feeding frequency and there was no significant difference between daily food intakes in M12 and M24 treatments. Growth rate, feed efficiency increased significantly with increasing feeding frequencies. Size variation was not affected by feeding frequency. Apparent digestibility of dry matter was not influenced by feeding frequency, while apparent digestibility of protein and energy increased significantly at high feeding frequencies. The feeding frequency had no significant effect on the moisture, lipid, protein, or energy contents of gibel carp, while the ash content decreased with increased feeding frequency. It was recommended that 24 meals per day was the optimal feeding frequency for juvenile gibel carp.