Genotoxicity assessment using micronuclei assay in rheumatoid arthritis patients

OBJECTIVES: This study investigated whether: (i) rheumatoid arthritis (RA) patients have more micronuclei (MN) than healthy controls; (ii) methotrexate (MTX) treated RA patients have more MN than those not using MTX, and (iii) folic acid supplementation decreases the number of MN in MTX treated patients. METHODS: MN assays were performed in oral mucosa sweeps of 50 consecutive MTX treated RA patients, 30 consecutive RA patients not receiving MTX and 39 healthy controls. MTX treated RA patients were then randomly placed in a cross-over design to receive folic acid supplementation, and MN assays were repeated after 6 weeks. RESULTS: The MTX-RA patients had a mean age of 46 +/- 10 yrs and a mean disease duration of 12 +/- 9 yrs; 80% were women. The MTX dose range was 8.7 +/- 1.5 mg/week and the mean duration of use was 16 +/- 18 months. In the non-MTX RA group, the mean age was 48 +/- 14 yrs, the mean disease duration was 13 +/- 9 yrs, and 87% were women. At baseline, the number of MN were significantly higher in RA patients as compared with controls (3.31 +/- 2.3 vs 0.8 +/- 0.8, p <0.001). No difference in MN numbers was observed between users and non-users of MTX. Folic acid supplementation did not decrease the MN number in the MTX treated RA patients. CONCLUSIONS: Genotoxicity, as assessed by the MN assay, is increased in RA patients. These results suggest that genotoxicity is associated with RA itself and not with MTX use. Folic acid supplementation had no effect on the number of MN.     

The estrogen receptor is not essential for all estrogen neuroprotection: new evidence from a new analog

We synthesized an estrogen analog, ZYC-5, lacking activity at the classical estrogen receptor and examined its neuroprotective potential against necrosis induced by N-methyl-d-aspartate (NMDA) and apoptosis/necrosis induced by the NMDA receptor antagonist (+)-3-(2-carboxypiperazine-4-yl)-propyl-1-phosphonic acid (CPP). ZYC-5 protected cortical neurons in a dose-dependent manner, and the neuroprotection was more robust than with 17beta-estradiol. The effect of ZYC-5 was not mediated by the classical estrogen receptor, because it was unaffected by the antagonists 4-hydroxytamoxifen and ICI 182,780. The ZYC-5 protection against excitotoxicity was not directly mediated through the NMDA receptor, because there was no effect of ZYC-5 on NMDA current or the intracellular calcium increase induced by NMDA. Results obtained with the free-radical-sensitive dye, dihydroethidium, suggested that the neuroprotection of ZYC-5 was partly related to its radical scavenging properties. Although some of estrogen's neuroprotective effects may depend upon the estrogen receptor, our results suggest the possibility of neuroprotection without hormonal side effects.     

新疆哈萨克族隔离群血管紧张素转换酶基因I/D多态性与高血压病的关系

目的 探讨哈萨克族人群血管紧张素转换酶(angiotensin converting enzyme,ACE)基因第16内含子中的插入／缺失(insertion／deletion，I／D)多态性是否为高血压病(essential hypertension，EH)的遗传易患因素。方法 应用聚合酶链反应检测了新疆巴里坤县201例哈萨克族高血压病患者和151名正常人的ACE基因16内含子I／D多态性。结果 哈萨克族正常人群及高血压患者的ACE基因I／D多态性DD、ID、Ⅱ基因型频率分布分别为0．17、0．43、0．40和0．18、0．52、0．30，D和I等位基因分布频率分别为0．39和0．61和0．44、0．56，符合Hardy-Weinberg平衡。群体相关分析结果表明，ACE基因的D及I等位基因分布在高血压病组及正常血压组的差异无显著性(x^2＝1．98，P＝0.16)；基因型频率之间差异也无显著性(x^2＝4．0，P＝0．14)。结论 ACE基因16内含子I／D多态性可能与新疆巴里坤哈萨克族高血压病无关。     

Decreased phosphorylation and protein expression of ERK1/2 in the brain of hypoxic preconditioned mice

Accumulated reports have suggested that activation of protein kinase C (PKC) isoforms may involve the activation of extracellular signal-regulated kinases 1/2 (ERK1/2) in the neuronal response to hypoxic stimuli. We have previously demonstrated that the membrane translocation or activation of conventional PKC (cPKC) betaII, gamma and novel PKC (nPKC) varepsilon are increased in the early phase of cerebral hypoxic preconditioning in mice. However, the role of ERK1/2 in the development of cerebral hypoxic preconditioning is unclear. In the current study, we used Western blot analysis to investigate the effects of repetitive hypoxic exposure (H0-H6, n=6 for each group) on the levels of phosphorylation and protein expression of ERK1/2 in the frontal cortex and the whole hippocampus of mice. We found that the levels of phosphorylated ERK1/2, not protein expression of ERK1/2, decreased significantly in both cortex and hippocampus of the early hypoxic preconditioned mice (H1-H4), when compared to that of the normoxic group (p<0.05). In addition, a significant decrease (p<0.05) in the ERK1/2 protein expression, not the phosphorylated form of ERK1/2, was found both in the frontal cortex and hippocampus of mice followed hypoxia with previous hypoxia (H5 and H6). These results suggest that the decreased phosphorylation and downregulation of protein expression of ERK1/2 might be involved in the development of hypoxic preconditioning.     

Towards the complex dependence of MTRasym on T1w in amide proton transfer (APT) imaging

Amide proton transfer (APT) imaging is a variation of chemical exchange saturation transfer MRI that has shown promise in diagnosing tumors, ischemic stroke, multiple sclerosis, traumatic brain injury, etc. Specific quantification of the APT effect is crucial for the interpretation of APT contrast in pathologies. Conventionally, magnetization transfer ratio with asymmetric analysis (MTR_asym) has been used to quantify the APT effect. However, some studies indicate that MTR_asym is contaminated by water longitudinal relaxation time (T_1w), and thus it is necessary to normalize T_1w in MTR_asym to obtain specific quantification of the APT effect. So far, whether to use MTR_asym or the T_1w‐normalized MTR_asym is still under debate in the field. In this paper, the influence of T_1w on the quantification of APT was evaluated through theoretical analysis, numerical simulations, and phantom studies for different experimental conditions. Results indicate that there are two types of T_1w effect (T_1w recovery and T_1w‐related saturation), which have inverse influences on the steady‐state MTR_asym. In situations with no or weak direct water saturation (DS) effect, there is only the T_1w recovery effect, and MTR_asym linearly depends on T_1w. In contrast, in situations with significant DS effects, the dependence of MTR_asym on T_1w is complex, and is dictated by the competition of these two T_1w effects. Therefore, by choosing appropriate irradiation powers, MTR_asym could be roughly insensitive to T_1w. Moreover, in non‐steady‐state acquisitions with very short irradiation time, MTR_asym is also roughly insensitive to T_1w. Therefore, for steady‐state APT imaging at high fields or with very low irradiation powers, where there are no significant DS effects, it is necessary to normalize T_1w to improve the specificity of MTR_asym. However, in clinical MRI systems (usually low fields or non‐steady‐state acquisitions), T_1w normalization may not be necessary when appropriate sequence parameters are chosen.     

On the origins of chemical exchange saturation transfer (CEST) contrast in tumors at 9.4 T

Chemical exchange saturation transfer (CEST) provides an indirect means to detect exchangeable protons within tissues through their effects on the water signal. Previous studies have suggested that amide proton transfer (APT) imaging, a specific form of CEST, detects endogenous amide protons with a resonance frequency offset 3.5 ppm downfield from water, and thus may be sensitive to variations in mobile proteins/peptides in tumors. However, as CEST measurements are influenced by various confounding effects, such as spillover saturation, magnetization transfer (MT) and MT asymmetry, the mechanism or degree of increased APT signal in tumors is not certain. In addition to APT, nuclear Overhauser enhancement (NOE) effects upfield from water may also provide distinct information on tissue composition. In the current study, APT, NOE and several other MR parameters were measured and compared comprehensively in order to elucidate the origins of APT and NOE contrasts in tumors at 9.4 T. In addition to conventional CEST methods, a new intrinsic inverse metric was applied to correct for relaxation and other effects. After corrections for spillover, MT and T₁ effects, corrected APT in tumors was found not to be significantly different from that in normal tissues, but corrected NOE effects in tumors showed significant decreases compared with those in normal tissues. Biochemical measurements verified that there was no significant enhancement of protein contents in the tumors studied, consistent with the corrected APT measurements and previous literature, whereas quantitative MT data showed decreases in the fractions of immobile macromolecules in tumors. Our results may assist in the better understanding of the contrast depicted by CEST imaging in tumors, and in the development of improved APT and NOE measurements for cancer imaging. Copyright © 2014 John Wiley & Sons, Ltd.     

血管紧张素Ⅱ对单核细胞趋化蛋白及基因调节的意义

目的　观察血管紧张素Ⅱ (AⅡ )对人单核细胞株THP 1分泌单核细胞趋化因子 (MCP 1)蛋白及基因的影响。方法　利用ELISA法检测AⅡ作用后THP 1分泌MCP 1的表达 ,利用RT PCR检测其MCP 1的mRNA表达。结果　 4种不同浓度的AⅡ (1× 10 -6、1× 10 -7、1× 10 -8、1× 10 -9mol/L)刺激THP 12 4h后 ,MCP 1蛋白及mRNA的表达明显增加 ,且呈浓度依赖性。结论　AⅡ可调节THP 1细胞MCP 1基因及蛋白的表达 ,AⅡ可通过致炎症作用参与动脉粥样硬化的发病过程     

Differentiating between Burkitt lymphoma and CD10+ diffuse large B-cell lymphoma: the role of commonly used flow cytometry cell markers and the application of a multiparameter scoring system

The goal of this study was to evaluate routine flow cytometric (FC) immunophenotypic markers in differentiating between Burkitt lymphoma (BL) and CD10+ diffuse large B-cell lymphoma (DLBCL). We performed retrospective analysis of FC data from 55 patients. We evaluated 9 FC parameters: forward and side scatter (FSC and SSC); mean fluorescent intensity (MFI) for CD20, CD10, CD38, CD79b, CD43, and CD71; and the percentage of neoplastic cells positive for CD71 (%CD71). The FSC; MFIs of CD10, CD43, CD79b, and CD71; and %CD71 cells were significantly different between BL and CD10+ DLBCL (P < .05; Student t test). A 5-point scoring system (FSC, %CD71, and MFIs of CD43, CD79b, and CD71) was devised, and 6 (60%) of 10 BLs scored 3 or greater and 1 (10%) of 10 CD10+ DLBCLs scored 3 (P = .04; χ(2)). Our findings indicate that routine FC parameters can aid in differentiating BL from CD10+ DLBCL.