电免疫学在心房颤动发病机制和诊疗策略中的研究进展

心房颤动(房颤)是临床上最常见的心律失常,严重影响患者生命健康及生活质量。目前房颤发生机制尚未完全阐明,研究表明免疫系统在房颤发生过程中被激活,参与心房重塑过程,并由此提出“电免疫学”的概念。现就免疫细胞电生理特性、免疫细胞与心肌细胞互作、免疫系统异常活动在房颤中的作用及机制进行系统综述。

Immunohistochemical localization of glutathione S-transferase-pi in human colorectal polyps

AIM:To investigate the distribution of the placental form of glutathione-S-transferase (GST) in colon polyps in order to evaluate the role of GST-pi in these tissues. METHODS: Sixteen polyp tissues removed at colonoscopy were examined. Tissues were investigated histologically and ultrastructurally. GST-pi expression was also analysed immunohistochemically, using peroxidase anti-peroxidase (PAP) method and immunogold labelling method, for light and electron microscope respectively. RESULTS: All polyp tissues examined were adenoma of low, mild and high-grade dysplasia as shown in the histopathological reports. Nevertheless, the examination of the above specimens with electron microscope revealed that 3 of 9 adenoma of mild dysplasia had ultrastuctural features similar to high-grade dysplasia adenoma. GST-pi was variably expressed in adenoma, with the lowest relative levels occurring in low-gradeadenoma and the highest levels found in high-grade adenoma. GST-pi was located mainly in undifferentiated epithelial cells. GST-pi positive particles were found in the cytoplasm and especially in the nucleus adjacent to the nuclear membrane of these cells. CONCLUSION:The overexpression of GST-pi in mildgrade adenomas with significant subcellular changes and in the majority of high-grade dysplasia adenoma suggests that this might be related to the carcinogenetic proceeding. Immunohistochemical localization of GST-pi in combination with ultrastructural changes indicate that GST-pi might be a sensitive agent for the detection of preneoplastic transformations in adenoma.

Proteomic analysis of gastric cancer and immunoblot validation of potential biomarkers

AIM： To search for and validate differentially expressed proteins in patients with gastric adenocarcinoma.METHODS： We used two-dimensional gel electrophoresis and mass spectrometry to search for differentially expressed proteins in patients with gastric adenocarcinoma. A set of proteins was validated with immunoblotting.RESULTS： We identified 30 different proteins involved in various biological processes： metabolism, development, death, response to stress, cell cycle, cell communication, transport, and cell motility. Eight proteinswere chosen for further validation by immunoblotting. Our results show that gastrokine-1, 39S ribosomal protein L12 （mitochondrial precursor）, plasma cell-induced resident endoplasmic reticulum protein, and glutathione S-transferase mu 3 were significantly underexpressed in gastric adenocarcinoma relative to adjacent non-tumor tissue samples. On the other hand, sep- tin-2, ubiquitin-conjugating enzyme E2 N, and transaldolase were significantly overexpressed. Translationally controlled tumor protein was shown to be differentially expressed only in patients with cancer of the gastric cardia/esophageal border.CONCLUSION： This work presents a set of possible diagnostic biomarkers, validated for the first time. It might contribute to the efforts of understanding gastric cancer carcinogenesis,

Effects and possible anti-tumor immunity of electrochemotherapy with bleomycin on human colon cancer xenografts in nude mice

AIM: To evaluate the anti-tumor effects and possible involvement of anti-tumor immunity of electrochemotherapy (ECT) employing electroporation and bleomycin in human colon cancer xenografts in nude mice, and to establish the experimental basis for clinical application of ECT. METHODS: Forty nude mice, inoculated subcutaneously human colon cancer cell line LoVo for 3 wk, were allocated randomly into four groups: B+E+ (ECT), B+E- (administration of bleomycin alone), B-E+ (administration of electric pulses alone), and B-E- (no treatment). Tumor volumes were measured daily. The animals were killed on the 7* d, the weights of xenografts were measured, and histologies of tumors were evaluated. Cytotoxicity of spleen natural killer (NK) and lymphokine-activated killer (LAK) cells was then assessed by lactic dehydrogenase release assay. RESULTS: The mean tumor volume of group B+E+ was statistically different from the other three groups after the treatment (F= 36.80, P<0.01). There was one case of complete response, seven cases of partial response (PR) in group B+E+, one case of PR in group B+E- and group B-E+ respectively, and no response was observed in group B-E-. The difference of response between group B+E+ and the other three groups was statistically significant (X2 = 25.67,P<0.01). Histologically, extensive necrosis of tumor cells with considerable vascular damage and inflammatory cells infiltration were observed in group B+E+. There was no statistical difference between the cytotoxicity of NK and LAK cells in the four treatment groups. CONCLUSION: ECT significantly enhances the chemosensitivity and effects of chemotherapy in human colon cancer xenografts in nude mice, and could be a kind of novel treatment modality for human colon cancer. The generation of T-cell-dependent, tumor-specific immunity might be involved in the process of ECT.

Primary hepatic carcinoid:A case report and literature review

Carcinoids are tumors derived from neuroendocrine cells and often produce functional peptide hormones.Approximately 54.5% arise in the gastrointestinal tract and frequently metastasize to the liver.Primary hepatic carcinoid tumors(PHCT) are extremely rare;only 95 cases have been reported.A 65-year-old man came to our attention due to occasional ultrasound findings in absence of clinical manifestations.His previous medical history,since 2003,included an echotomography of the dishomogeneous parenchymal area but no focal lesions.A computed tomography scan performed in 2005 showed an enhanced pseudonodular-like lesion of about 2 cm.Cholangio-magnetic resonance imaging identified the lesion as a possible cholangiocarcinoma.No positive findings were obtained with positron emission tomography.Histology suggested a secondary localization in the liver caused by a low-grade malignant neuroendocrine tumor.Immunohistochemistry was positive for anti chromogranin antibodies,Ki67 antibodies and synaptophysin.Octreoscan scintigraphy indicated intense activity in the lesion.Endoscopic investigations were performed to exclude the presence of extrahepatic neoplasms.Diagnosis of PHCT was established.The patient underwent left hepatectomy,followed by hormone therapy with sandostatine LAR.Two months after surgery he had a lymph nodal relapse along the celiac trunk and caudate lobe,which was histologically confirmed.The postoperative clinical course was uneventful,with a negative follow-up for hematochemical,clinical and radiological investigations at 18 mo post-surgery.Diagnosis of PHCT is based principally on the histopathological confi rmation of a carcinoid tumor and the exclusion of a non-hepatic primary tumor.Surgical resection is the recommended primary treatment for PHCT.Recurrence rate and survival rate in patients treated with resection were 18% and 74%,respectively.

Development of an electrochemical immunoassay for detection of gatifloxacin in swine urine

To detect gatifloxacin （GAT） residue in swine urine, an electrochemical immunoassay was established, An indirect competitive immunoassay was developed, in which the coating antigen is immobilized in an enzyme-linked immunosorbent assay （ELISA） plate and GAT residue from the sample competes with the limited binding sites in added anti-GAT antibody. Horseradish peroxidase （HRP） conjugated to goat anti-rabbit IgG was used as the enzymatic label. A carbon fiber working electrode was constructed and current signals were detected by using hydrogen peroxide as a substrate and hydroquinone as an electrochemical mediator. The electrochemical immunoassay was evaluated by analysis of GAT in buffer or swine urine and an average value of half inhibition concentration （IC50） of 8.9 ng/ml was obtained. Excellent specificity of the antibody was achieved with little cross-reaction with Iomefloxacin （3.0%）, ciprofloxacin （3.0%）, and ofloxacin （1.9%） among commonly used （fluoro）quinolones. In conclusion, the im- munoassay system developed in this research can be used as a rapid, powerful and on-site analytical tool to detect GAT residue in foods and food products.

Comparative effect of electroacupuncture and moxibustion on the expression of substance P and vasoactive intestinal peptide in patients with irritable bowel syndrome

OBJECTIVE: To compare the impacts of electroacupuncture(EA) and moxibustion(Mox) on the primary gastrointestinal symptoms and the expressions of colonic mucosa-associated neuropeptide substance P(SP) and vasoactive intestinal peptide(VIP)in patients with either diarrhea-predominant or constipation-predominant irritable bowel syndrome(IBS-D and IBS-C,respectively).METHODS: Eighty-five IBS patients were randomly allocated to the EA and Mox groups. Zusanli(ST 36)and Shangjuxu(ST 37) were selected as acupoints for electroacupuncture or warm moxibustion treatment once a day for 14 consecutive days. Before and after the treatment sessions,a Visual Analog Pain Scale and the Bristol Stool Form Scale were used to evaluate gastrointestinal symptoms. There were four dropout cases,leaving 81 participants(41 with IBS-D and 40 with IBS-C) who volunteered to undergo colonoscopy before and after the treatment sessions. During colonoscopy,sigmoid mucosa were collected to detect SP and VIP expression using immunohistochemistry assay.RESULTS: Both EA and Mox treatments were effective at relieving abdominal pain in IBS-D and IBS-C patients. However,Mox was more effective at reducing diarrhea in IBS-D patients,whereas EA was more effective at improving constipation in IBS-C patients. EA and Mox treatments both down-regulated the abnormally increased SP and VIP expression in the colonic mucosa,with no significant difference shown between the two treatments.CONCLUSION: Both EA and Mox treatments are effective at ameliorating gastrointestinal symptoms by reducing SP and VIP expression in the colonic mucosa of IBS patients.

An anti-passivation ink for the preparation of electrodes for use in electrochemical immunoassays

p-Nitrophenylphosphate （PNPP） is usually employed as the substrate for enzyme-linked immunosorbent assays, p-Nitrophenol （PNP）, the product of PNPP, with the catalyst alkaline phosphatase （ALP）, will passivate an electrode, which limits applications in electrochemical analysis. A novel anti-passivation ink used in the preparation of a graphene/ionic liquid/chitosan composited （rGO/IL/Ghi） electrode is proposed to solve the problem. The anti-passivation electrode was fabricated by directly writing the graphene-ionic liquid-chitosan composite on a single-side conductive gold strip. A glassy carbon electrode, a screen-printed electrode, and a graphene-chitosan composite-modified screen-printed electrode were investigated for comparison. Scanning electron microscopy was used to characterize the surface structure of the four different electrodes and cyclic voltammetry was carried out to compare their performance. The results showed that the rGO/IL/Ghi electrode had the best performance according to its low peak potential and large peak current. Amperometdc responses of the different electrodes to PNP proved that only the rGO/IL/Chi electrode was capable of anti-passivation. The detection of cardiac troponin I was used as a test example for electrochemical immunoassay. Differential pulse voltammetry was performed to detect cardiac troponin I and obtain a calibration curve. The limit of detection was 0.05 ng/ml.

Gold nanolabels and enzymatic recycling dual amplification-based electrochemical immunosensor for the highly sensitive detection of carcinoembryonic antigen

A sensitive electrochemical immunoassay system for the detection of a protein tumor biomarker through a dual amplified strategy was reported. Firstly, this protocol involves in the electropolymerization of o-aminobenzoic acid (o-ABA) on a glass carbon electrode (GCE). Subsequently, capture anti-CEA (Abl) is covalently linked to poly(o-ABA) (PAB) film, via N-(3-dimethylamminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC), and N-hydroxysulfosuccinimid sodium salt (NHS) activation of the carboxyl groups and surface blocking with ethanolamine. Later, the target, carcinoembryonic antigen (CEA), is sandwiched between an electrode surface confined Ab1 and the alkaline phosphatase-labeled signal anti-CEA antibodies conjugated with gold nanoparticles (Ab2-ALP-AuNP bioconjugates). The dual biocatalytic signal amplification for CEA monitoring is achieved by coupling the numerous enzymes loaded on the AuNPs with redox-recycling of the enzymatic products in the presence of the secondary enzyme and the corresponding substrate. The novel dramatic signal amplification strategy, exhibits a good linearity at the studied concentration range from 0.005 to 50 ng mL-1 towards CEA with a detection limit of 2 pg mL-1 (S/N=3). There is a 5-100-fold improvement in detection limit compared to other similar studies. The developed dual signal amplified strategy shows good selectivity, regeneration, stability and acceptable reproducibility. Therefore, the signal amplification approach holds great potential applications in detection of ultra-trace protein biomarkers.

Ultrasensitive label-free electrochemiluminescence immunosensor based on N-(4-aminobutyl)-N-ethylisoluminol-functionalized graphene composite

The electrochemiluminescence(ECL) behavior of N-(4-aminobutyl)-N-ethylisoluminol(ABEI)-functionalized graphene composite(ABEI-GC) modified on an indium tin oxide(ITO) electrode was studied. ABEI-GC exhibited excellent ECL activity. On this basis, a label-free ECL immunosensor was developed for the sensitive detection of human immunoglobulin G(h Ig G) by using ABEI-GC as the ECL nano-interface via a layer-by-layer assembly technique. ABEI-GC was first assembled onto an ITO electrode. Positively charged chitosan was then electrostatically adsorbed to the modified electrode. Finally, negatively charged antibody-coated gold nanoparticles were attached to the surface to form the ECL immunosensor. In the presence of h Ig G, h Ig G was captured by its antibody. In addition, an ECL signal was detected in the presence of H2O2 when a double potential was applied. The ECL immunosensor for the determination of h Ig G showed a linear range of 1.0×10-13–1.0×10-8 g/mL with a detection limit of 5.0×10-14 g/m L. This immunosensor has high sensitivity, wide linearity and good reproducibility. The superior sensitivity of the proposed ECL immunoassay mainly derives from the incorporation of ABEI-GC, which not only improves the ECL intensity, response speed, and stability, but also provides a large specific surface for high levels of protein loading. This work reveals that ABEI-GC is good nano-interface for the construction of ECL biosensors. Our strategy is promising for protein detection and may open up a new avenue for ultrasensitive label-free immunoassays.