A robust method for simultaneous determination of eight B vitamins in human serum by liquid chromatography tandem mass spectrometry.

The level of vitamin B group in human serum is an important index of human health. Among B vitamins, cyanocobalamin in serum is unstable and its content is extremely low. Rapid and simultaneous detection of multiple B vitamins including cyanocobalamin is a challenge. Herein, we have developed a rapid and stable method that can realize the determination of thiamine, riboflavin, nicotinamide, pantothenic acid, pyridoxic acid, biotin, 5-methyltetrahydrofolate, and cyanocobalamin simultaneously in 6 min. The method was established based on protein precipitation with methanol and then chromatographic separation was achieved using Waters acquity ultra-high-performance liquid chromatography high strength silica T3 column, which was stable and sensitive especially for cyanocobalamin. Limit of quantification, precision, trueness, and matrix effect were validated according to the European Medicines Agency and United States Food and Drug guidelines and Clinical and Laboratory Standards Institute guidelines on bioanalytical method. The limit of quantification for thiamine, riboflavin, nicotinamide, pantothenic acid, pyridoxic acid, biotin, 5-methyltetrahydrofolate, and cyanocobalamin was 0.4, 0.4, 0.8, 2.0, 0.4, 0.1, 0.4, and 0.04 ng/mL separately, respectively. Intra- and interday precisions were 1.1%-12.4% and 2.0%-13.5%, respectively. The relative errors were between 0.3% and 13.3%, and the matrix effects were between 2.6% and 10.4%.

Circular RNA circEYA3 promotes the radiation resistance of hepatocellular carcinoma via the IGF2BP2/DTX3L axis.

BACKGROUND: Hepatocellular carcinoma (HCC) has a high incidence and mortality rate despite various treatment options, including 125I seed implantation. However, recurrence and radiation resistance remain challenging issues. Hsa_circ_0007895 (circEYA3)-derived from exons 2-6 of EYA3-facilitates the proliferation and progression of pancreatic ductal adenocarcinoma. However, the role of circEYA3 in HCC 125I radiation resistance remains unclear. Thus, we aimed to investigate the functions and underlying molecular mechanisms of circEYA3 in HCC under 125I and X-ray irradiation conditions. METHODS: CircEYA3 was identified by RNA-seq in patients with HCC before and after 125I seed implantation treatment, followed by fluorescence in situ hybridization and RNase R assays. The radiosensitivity of HCC cell lines irradiated with 125I seeds or external irradiation were evaluated using the Cell Counting Kit 8, flow cytometry, γH2A.X immunofluorescence and comet assays. RNA pull-down and RNA immunoprecipitation assays were performed to explore the interactions between circEYA3 and IGF2BP2. DTX3L mRNA was identified by RNA-seq in PLC/PRF/5 cells with overexpressed circEYA3. The corresponding in vitro results were verified using a mouse xenograft model. RESULTS: CircEYA3 decreased the radiosensitivity of HCC cells both in vitro and in vivo. Notably, using a circRNA pulldown assay and RNA-binding protein immunoprecipitation, we identified IGF2BP2 as a novel and robust interacting protein of circEYA3. Mechanistically, circEYA3 binds to IGF2BP2 and enhances its ability to stabilize DTX3L mRNA, thereby specifically alleviating radiation-induced DNA damage in HCC cells. CONCLUSIONS: Our findings demonstrate that circEYA3 increases the radioresistance of HCC to 125I seeds and external irradiation via the IGF2BP2/DTX3L axis. Thus, circEYA3 might be a predictive indicator and intervention option for 125I brachytherapy or external radiotherapy in HCC.

High Diagnostic Accuracy and Safety of Endoscopic Ultrasound-Guided Fine-Needle Aspiration in Malignant Lymph Nodes: A Systematic Review and Meta-Analysis.

BACKGROUND AND AIMS: Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is increasingly being used for diagnosing lymphadenopathy. We aim to systematically review the accuracy of EUS-FNA in differentiating benign and malignant mediastinal and abdominal lymph nodes (LNs). METHODS: A comprehensive literature search was performed on multiple electronic databases through February 2020. A random or fixed effect model generated the pooled sensitivity, specificity, likelihood ratio (LR), and diagnostic odds ratio (DOR) of EUS-FNA. Subgroup analyses and meta-regression were used to explore sources of heterogeneity. RESULTS: Twenty-six studies involving 2753 patients with 2833 LNs were included. In the differential diagnosis of benign and malignant LNs, EUS-FNA had a pooled sensitivity, specificity, positive LR, and negative LR of 87% (95% confidence interval [CI] 86-90%), 100% (95% CI 99-100%), 68.98 (95% CI 42.10-113.02), and 0.14 (95% CI 0.11-0.17), respectively. The pooled rate of adverse events associated with EUS-FNA was 1.57% (95% CI 1.06-2.24%). The summary receiver operating characteristic (SROC) yielded an area under the curve (AUC) of 0.9912. EUS-FNA performed in mediastinal LNs gained a sensitivity of 85% (95% CI 81-88%), while in abdominal LNs, it reached 87% (95% CI 82-91%). The sensitivity of the subgroup with rapid on-site evaluation (ROSE) was 91% (95% CI 89-93%), while non-ROSE was 85% (95% CI 82-87%). CONCLUSIONS: EUS-FNA is a sensitive, highly specific, and safe method for distinguishing benign and malignant mediastinal or abdominal LNs. However, the sensitivity of EUS-FNA still varies significantly among different centers.

Short report: sleep quality and associations with health locus of control and coping styles in young people with ankylosing spondylitis.

The poor sleep of young people with ankylosing spondylitis (AS) has not attracted enough attention of clinicians and experts. This study aimed to evaluate the sleep quality and associations with health locus of control (HLC) and coping styles in young people with AS. A total of 133 patients completed the measures of demographics, disease characteristics, HLC, coping styles, and Pittsburgh sleep quality index (PSQI). The patients were worse than general population in PSQI global score and multiple domains. Among patients, the poor sleep was positively related to chance HLC (CHLC) and resignation. Resignation completely mediated the association between CHLC and sleep. There were severe sleep problems in young people with AS, and strategies to change the resignation coping style should be implemented.

Analysis of Fine-Needle Biopsy vs Fine-Needle Aspiration in Diagnosis of Pancreatic and Abdominal Masses: A Prospective, Multicenter, Randomized Controlled Trial.

BACKGROUND & AIMS: Endoscopic ultrasound (EUS)-guided fine needles with side fenestrations are used to collect aspirates for cytology analysis and biopsy samples for histologic analysis. We conducted a large, multicenter study to compare the accuracy of diagnosis via specimens collected with fine-needle biopsy (FNB) versus fine-needle aspiration (FNA) for patients with pancreatic and nonpancreatic masses. METHODS: We performed a prospective single-blind study at 5 tertiary care centers in China. The study comprised 408 patients undergoing EUS for a solid mass (>1 cm) in the pancreas, abdomen, mediastinum, or pelvic cavity, from December 2014 through January 2016. Patients were randomly assigned to groups (1:1) for assessment by FNA (n = 190) or FNB (n = 187). After lesions were identified by EUS, samples were collected in a total of 4 passes by each needle. All procedures were performed by experienced endosonographers; cytologists and pathologists were blinded to the sample collection method. Patients were followed for at least 48 weeks, and final diagnoses were obtained after surgery, imaging analysis, or resolution of lesion. The primary aim was to compare diagnostic yields of EUS-FNA with EUS-FNB for all solid masses, then separately as pancreatic and nonpancreatic masses. The secondary endpoint was the quality of histologic specimen. RESULTS: Findings from FNB analysis were accurate for 91.44% of all cases, compared with 80.00% for all FNA cases, based on final patient diagnoses (P = .0015). In patients with pancreatic masses (n = 249), findings from histologic analysis of FNBs were accurate for 92.68% of the cases, compared with 81.75% for FNAs (P = .0099). In cytology analysis of pancreatic masses, samples collected by FNB accurately identified 88.62% of all pancreatic lesions, whereas samples collected by FNA accurately identified 79.37% (P = .00468). Analyses of samples of nonpancreatic masses collected by FNA versus FNB produced similar diagnostic yields. CONCLUSIONS: In a prospective study of patients with pancreatic masses, we found EUS-guided FNB samples to produce more accurate diagnoses than samples collected by EUS-guided FNA samples. No difference in diagnostic yield was seen between EUS-FNA and EUS-FNB for nonpancreatic masses. Clinical Trials.gov no: NCT02327065.

Magnifying endoscopy with narrow-band imaging to assist the linear stapler closure of the pharynx during total laryngectomy.

OBJECTIVE: This study aimed to present a novel technique for stapler-assisted laryngectomy under direct visualization using a videoendoscope with narrow-band imaging (NBI-endoscopy). METHODS: A case series of five consecutive patients were treated with stapler-assisted total laryngectomy from December 2014 to March 2016. The technique involved monitoring the stapler closure of laryngopharyngeal cavity under NBI-endoscopic vision, triple checking of neo-pharynx cavity by an endoscopic view inside and transillumination verification outside, air leakage test, and guiding the insertion of feeding tube under direct visualization. The main evaluation of this study was pharyngocutaneous fistula, surgical margin, and oral feeding time. RESULTS: All the patients healed well without a pharyngocutaneous fistula. The mean of surgical time, oral feeding, and hospitalization time were 40 min, 6 days, and 8 days, respectively. CONCLUSION: This study demonstrated a technique simple to learn and associated with decreased complication rates, which could be safe and efficient for stapler-assisted laryngectomy.

Managing esophageal fistulae by endoscopic transluminal drainage in esophageal cancer patients with superior mediastinal sepsis after esophagectomy.

The management of postoperative leaks into the mediastinum after esophagectomy remains a challenge. We describe our clinical management of this complication through endoscopic transluminal drainage. Between 2008 and 2011, 4 patients with esophageal squamous cell carcinoma (ESCC) who underwent McKeown-type esophagectomy with two-field lymphadenectomy experienced complicated anastomotic fistulae in the presence of superior mediastinal sepsis. All 4 patients underwent endoscopic transluminal drainage, and all survived. The mean healing period was 50 days (range, 31 to 58 days), the mean stay in the intensive care unit was 7.3 days (range, 1 to 18 days), and the mean hospital stay was 64.5 days (range, 49 to 70 days). Endoscopically guided transluminal drainage should be considered for ESCC patients with superior mediastinal fistulae after esophagectomy.

Rapid simultaneous determination of 7 fat-soluble vitamins in human serum by ultra high performance liquid chromatography tandem mass spectrometry.

Accurate detection of vitamins is critically important for clinical diagnosis, metabolomics and epidemiological studies. However, the amounts of different vitamins vary dramatically in human serum. It is a challenge to achieve simultaneous detection of multiple vitamins rapidly. Herein, we developed and validated a sensitive and specific method using ultra high-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) for simultaneous quantification of 7 fat-soluble vitamins (FSVs) across their physiological concentrations in serum for the first time, which was subjected to protein precipitation, liquid-liquid extraction to an organic phase, evaporation to dryness and reconstitution with acetonitrile. In the present procedure, retinol (vitamin A), ergocalciferol (25-OH-D2), cholecalciferol (25-OH-D3), α-tocopherol (vitamin E), phylloquinone (vitamin K1), menatetrenone-4 (MK-4), and menaquinone-7 (MK-7) were detected in one analytical procedure for the first time within 5.0 min by triple quadrupole tandem mass spectrometry. The limit of quantification (LOQ) for vitamin A was 10.0 ng mL-1, LOQs for 25-OH-D2 and 25-OH-D3 were 1.0 ng mL-1, LOQ for vitamin E was 100.0 ng mL-1, and LOQs for vitamin K1, MK-4 and MK-7 were 0.10 ng mL-1, respectively, with a correlation (R2) of 0.995-0.999. Recoveries ranged from 80.5% to 118.5% and the intra-day and inter-day coefficients of variance (CVs) were 0.72-8.89% and 3.2-9.0% respectively. The method was validated according to the European Medicines Agency (EMA) and U.S. Food and Drug guidelines and C62-A on bioanalytical methods, and was used for clinical routine determination.

Short-Term Efficacy of the Transnasal-Transoral Approach to Endoscopic Nasopharyngectomy for Nasopharyngeal Adenocarcinoma.

OBJECTIVES: Nasopharyngeal adenocarcinomas (NPACs) are rare malignant tumors. The treatment of NPACs is usually surgery with resection of normal nasal passage tissues.We introduced an innovative double endoscopic surgery for NPACs patients and evaluated the clinical efficacy of this approach. METHODS: The clinical data of 4 NPACs patients who underwent radical endoscopic nasopharyngectomy using a combined transnasal and transoral approach were analyzed to determine the efficacy of this surgery. The endpoints were en bloc resection and relief of clinical symptoms. RESULTS: All surgeries were successfully performed without any severe postoperative complications or death. Postoperative MRI revealed that en bloc resection was achieved for all patients with NPACs, and they had high quality of life without postoperative complications. CONCLUSIONS: The transnasal-transoral approach to endoscopic nasopharyngectomy for nasopharyngeal adenocarcinoma is safe and effective.

Sensitive lateral flow assay for bisulfite-free DNA methylation detection based on the restriction endonuclease GlaI and rolling circle amplification.

The detection of DNA methylation with high sensitivity and specificity is important for the early diagnosis of many human diseases, including cancers. Here, we integrated the high specificity of the methylation-dependent restriction endonuclease GlaI for methylation-dependent digestion and the high amplification efficiency of rolling circle amplification (RCA) for the detection of GlaI digestion products. GlaI can only digest a methylated template, leading to the generation of digestion products with specific ends. The specific digestion product can then be ligated to a ligation mediator with a dumbbell structure to generate a complete circular template for further RCA, and the final RCA amplicon can be detected using lateral flow detection (LFD) with the naked eye. The specificity of Gla-RCA not only depends on the specific methylation digestion of GlaI, but only the ligation process of RCA amplification. As a proof of principle, the sensitivity of GlaI-RCA assay was applied to methylated Septin 9 and showed a sensitivity of approximately 1% (50 copies of methylated template per reaction) and no cross-reactivity with 5000 copies of unmethylated DNA used as background. The application of GlaI-RCA was also evaluated with colorectal cancer tissue samples and showed great accordance with standard bisulfite sequencing. A bisulfite-free and LFD-based DNA methylation detection was successfully developed, promising high specificity and rapid visual detection and having a great potential to become a robust tool for DNA methylations analysis.

Treatment of obstructive jaundice induced by non-hodgkin lymphoma with EUS-guided transgastric anterograde common bile duct stenting: Technical case report and literature review.

Background: Non-Hodgkin lymphoma (NHL) is a rare cause of biliary obstruction. The optimum treatment for these patients is unclear. Lymphoma-associated obstructive jaundice is generally managed with open surgery, Endoscopic retrograde cholangiopancreatography (ERCP), or Percutaneous transhepatic biliary drainage. Here, we present the first description of EUS-guided anterograde common bile duct stenting via the stomach for obstructive jaundice associated with NHL. Patient and methods: A 58-year-old male patient who had been undergoing chemotherapy for NHL was admitted to our institution for severe obstructive jaundice. The patient's hepatic function indicators were: alanine aminotransferase 211 U/L, aspartate aminotransferase 301 U/L, total bilirubin 485.6 µmol/L, and direct bilirubin 340.2 µmol/L. Abdominal magnetic resonance imaging showed massive lymphomatous lesions filling the peritoneal cavity. Magnetic resonance cholangiopancreatography revealed an external compressive stricture in the superior middle common bile duct and dilation of the intrahepatic and extrahepatic ducts. ERCP was performed unsuccessfully, due to the stricture at the descending junction of the duodenal bulb caused by lymphoma infiltration. So, EUS-guided anterograde common bile duct stenting via the stomach was performed. Results: The patient's bilirubin level decreased significantly in the postoperative period, and no adverse reaction was observed. Computed tomography showed marked shrinking of the abdominal mass after targeted therapy. Conclusions: Our report suggests that early relief of biliary obstruction may be more beneficial to subsequent chemotherapy when symptoms of lymphoma-associated jaundice are persistently aggravating. Endoscopic ultrasound-guided biliary drainage is a safe, effective and timely alternative approach to treat biliary obstruction when ERCP fails, especially in cases of malignancy caused by extrahepatic bile duct space-occupying lesions.

Application of endoscopic sonography in preoperative staging of rectal cancer: six-year experience.

OBJECTIVES: The aim of this study was to evaluate our experience with the application of endoscopic sonography in preoperative staging of rectal cancer. METHODS: Between April 2004 and May 2010, 192 patients with rectal cancer first underwent endoscopic sonography and then underwent surgery at our hospital. None of the patients in this study received neoadjuvant therapy. The endoscopic sonographic staging results were compared with those of postoperative pathologic staging. RESULTS: The accuracy of overall T staging was 86.5%, and for T1, T2, T3, and T4, the accuracy rates were 86.7%, 94.0%, 86.2%, and 65.5%, respectively. The accuracy of T staging for ulcerated lesions was significantly lower than that for nonulcerated lesions (P = .013). The accuracy of T staging between nontraversable stenotic lesions and traversable lesions was also significantly different (P = .002). The accuracy of N staging was 77.8%, and the specificity and sensitivity were 85.6% and 74.2%, respectively. CONCLUSIONS: Endoscopic sonography is safe and effective for preoperative staging of rectal cancer and should be a routine examination before surgery. As for ulcerated and nontraversable stenotic lesions, however, the results of endoscopic sonographic staging could be doubtful. Moreover, the accuracy of endoscopic sonographic N staging still needs modification by further research.

PFKFB4 Overexpression Facilitates Proliferation by Promoting the G1/S Transition and Is Associated with a Poor Prognosis in Triple-Negative Breast Cancer.

BACKGROUND: 6-Phosphofructo-2-kinase/fructose-2,6-biphosphate-4 (PFKFB4) is a key factor that plays an important role in tumorigenesis. However, its role in triple-negative breast cancer (TNBC) progression needs to be further validated. We investigated whether PFKFB4 is directly involved in the oncogenic signaling networks of TNBC. METHODS: First, we assessed the expression level of PFKFB4 in tumor tissue specimens by immunohistochemistry and evaluated its prognostic value. Next, the effect of PFKFB4 on TNBC cell growth and associated mechanisms were investigated. Finally, the results were further verified in vivo. RESULTS: We found that PFKFB4 overexpression was associated with an unfavorable prognosis in TNBC patients. PFKFB4 was overexpressed in TNBC cell lines in hypoxic environments, and its overexpression promoted tumor progression in vitro and in vivo. Further analyses demonstrated that the possible mechanism might be that PFKFB4 overexpression facilitates TNBC progression by enhancing the G1/S phase transition by increasing the protein level of CDK6 and phosphorylation of Rb. CONCLUSIONS: These data suggest that PFKFB4 plays significant roles in the tumorigenesis and development of TNBC.

S100A1 is a sensitive and specific cardiac biomarker for early diagnosis and prognostic assessment of acute myocardial infarction measured by chemiluminescent immunoassay.

BACKGROUND: A member of the S100 family of Ca2+-binding proteins, S100A1 is highly expressed in cardiac muscle tissue. Although this protein is considered an indicator of acute myocardial infarction (AMI), high-throughput and sensitive detection methods are still urgently needed. We constructed a rapid and sensitive method for detecting S100A1 and to investigate the clinical utility of S100A1 as a biomarker for the early diagnosis of AMI and subsequent prognostic assessments. We developed an automated chemiluminescent immunoassay to detect S100A1. We then analyzed the performance of the newly developed assay including evaluation of the analytical sensitivity, analytical selectivity, linear range, accuracy and repeatability. METHODS: We recruited 87 patients with AMI or angina pectoris to explore the value of this marker for the early diagnosis and prognostic assessment. RESULTS: The chemiluminescent-immune-based S100A1 assay had functional analytical sensitivity with a detection limit of 0.13 ng/ml, and a wide linear range of 0.13-31.66 ng/ml. It also exhibited good repeatability with intra-assay and inter-assay findings of <5% and <15%, respectively. Plasma S100A1 was found to have a higher diagnostic sensitivity than conventional cardiac biomarkers (creatine kinase-MB and cardiac troponin T). The survival analysis showed that a higher concentration of plasma S100A1 (>1.02 ng/ml) was notably associated with the poor prognosis of AMI patients after first PCI. CONCLUSIONS: Measurement of circulating S100A1 concentrations with our newly developed chemiluminescent-immune-based assay shows potential for use in the clinic. This assay could enable early identification and prognostic assessment of AMI.

Submucosal Saline Injection Followed by Endoscopic Ultrasound versus Endoscopic Ultrasound Only for Distinguishing between T1a and T1b Esophageal Cancer.

PURPOSE: To examine whether submucosal saline injection (SSI) can improve traditional endoscopic ultrasound (EUS) accuracy in distinguishing between T1a and T1b stage esophageal squamous cell carcinoma (ESCC). EXPERIMENTAL DESIGN: Patients with T1N0M0 stage ESCC (n = 180) ages 18 to 85 years were enrolled between February 14, 2012 to June 4, 2018 at Sun Yat-sen University Cancer Center (Guangdong, China). They were randomly assigned (1:1) to receive either EUS examination after 3-5 mL SSI or EUS only examination. All the patients were referred to thoracic surgeons to receive endoscopic resection (ER) or esophagectomy 5 to 10 days after EUS examination. Standard EUS criteria were used to preoperatively stage the ESCC cases, and surgical pathology reports after referral were used to postoperatively stage the cases. The primary endpoint was the diagnostic accuracy of T1b staging [defined as the sum of the true positive (T1b) and true negative (T1a) cases divided by the total number of cases]. RESULTS: Among the per-protocol population, the SSI+EUS group (n = 81) was superior to the EUS-only group (n = 85) in terms of the diagnostic accuracy for T1b staging [93.8% (95% confidence interval (CI), 88.6-99.1) vs. 65.9% (95% CI, 55.8-76.0); P < 0.001]. The positive predictive value of SSI+EUS for diagnosing T1b ESCC reached 90.9% (95% CI, 81.1-100), which was significantly superior to that of EUS only [0.576 (0.450-0.702), P = 0.001]. CONCLUSIONS: SSI significantly improves the diagnostic accuracy of EUS in distinguishing between T1a and T1b ESCC, which might help avoid unnecessary esophagectomy and diagnostic ER.

Probucol attenuates atrial structural remodeling in prolonged pacing-induced atrial fibrillation in dogs.

AIMS: Oxidative stress has recently been implicated in atrial fibrillation (AF); however, the mechanisms remain unclear. Herein, we hypothesize that probucol can attenuate atrial structure remodeling. METHODS: Twenty dogs were randomly divided into sham-operated, control, and probucol-treated groups. We identified apoptosis and histopathological changes in the atria. Oxidative stress was measured by lipid peroxidation and echocardiographic examinations were performed. RESULTS: Atrial apoptosis indexes were dramatically decreased in the probucol-treated group compared to the control group. Relative to the control group, the percentage of myolysis was dramatically decreased in the probucol-treated group (p < 0.01). There was less lipid peroxidation in the probucol-treated group than the control group. Atrial function was dramatically elevated in the probucol-treated group. CONCLUSIONS: The results of this study indicate that the antioxidant probucol suppresses atrial structural remodeling and may act as a new therapy for AF.

Rapid Detection of Bacillus cereus Using Cross-Priming Amplification.

Bacillus cereus is a spore-forming gastrointestinal pathogen that can cause life-threatening diseases. Here, a simple and effective assay to detect B. cereus was developed, using cross-priming amplification (CPA). Amplicons were detected using disposable cartridges that contained nucleic acid detection strips. The sensitivity of CPA assay for B. cereus was assessed using serial dilutions of genomic DNA, which indicated a detection limit of 3.6 × 101 CFU/mL. No cross-reactions were detected when genomic DNA extracted from 12 different B. cereus strains and 20 other bacterial foodborne strains were tested, suggesting that the assay is highly specific. Finally, we evaluated the practical applications of the CPA assay for the detection of B. cereus in 150 food samples and found that its sensitivity and specificity, compared with real-time PCR, were approximately 98.18 and 100%, respectively. In conclusion, CPA combined with nucleic acid detection strips is easy to perform, requires simple equipment, and offers highly specific and sensitive B. cereus detection.

Calpain I inhibition prevents atrial structural remodeling in a canine model with atrial fibrillation.

BACKGROUND: Atrial fibrillation (AF) is accompanied by atrial structural remodeling. Calpain activity is induced during AF. To test a causal relationship between calpain activation and atrial structural changes, N-acetyl-Leu-Leu-Met (ALLM), a calpain inhibitor, was utilized in a canine AF model. METHODS: Fifteen dogs were randomly divided into 3 groups: sham-operated group, control group and calpain inhibitor group; each with 5 dogs. Sustained AF was induced by rapid right atrium pacing at 600 beats per minute for 3 weeks. ALLM was administered at a dosage of 1.0 mg x kg(-1) x d(-1) in the calpain inhibitor group. Three weeks later, the proteolysis, protein expression of TnT and myosin, calpain I localization and expression and structural changes were examined in left atrial free walls, right atrial free walls and the interatrial septum respectively. Atrial size and contractile function were also measured by echocardiography. RESULTS: Long-term rapid atrial pacing induced marked structural changes such as enlarged atrial volume, myolysis, degradation of TnT and myosin, accumulation of glycogen and changes in mitochondrial shape and size, which were paralleled by an increase in calpain activity. The positive correlation between calpain activity and the degree of myolysis (r(s) = 0.90 961, P < 0.0001) was demonstrated. In addition to structural abnormalities, pacing-induced atrial contractile dysfunction was observed in this study. The pacing-induced atrial structural alterations and loss of contractility were partially prevented by the calpain inhibitor ALLM. CONCLUSIONS: Activation of calpain represents key features in the progression towards overt structural remodeling. Calpain inhibitor, ALLM, suppressed the increased calpain activity and reversed structural remodeling caused by sustained atrial fibrillation in the present model. Calpain inhibition may therefore provide a possibility for therapeutic intervention in AF.

[Influence of oxidative stress on atrial myocardium pathohistological and ultrastructural changes in atrial fibrillation: experiment with dogs].

OBJECTIVE: To evaluate the effects of oxidative stress on the protein expression of atrial calpain I and pathohistological and ultrastructural changes of atrial myocardium in atrial fibrillation (AF). METHODS: Twenty dogs were all implanted with pacemaker in a subcutaneous pocket and attached to a screw-in epicardial lead in right atrial appendage. They were randomly divided into 3 groups: sham-operation group (n = 6 without pacing), control group (n = 7 per minutes for 6 weeks), and probucol group (n = 7, pacing 1 week after recovery for 6 weeks, and administration of probucol 100 mg x kg(-1) x d(-1) 1 week before pacing till the end of pacing). One thin silicon plaque containing 4 pairs of electrodes were sutured to the right atrium. The dogs in control group, probucol group were paced at 400 beats per minutes for 6 weeks. Then the dogs were killed with their hearts taken out. The expression of atrial calpain I was measured by Western-blotting and immunohistochemistry. The pathohistological and ultrastructural changes in atrial tissue were tested by light and electron microscopy. The inducibility and duration of AF were measured in the control group and probucol group. The indexes of oxidative stress total anti-oxidation capability (T-AOC), malonyldiadehyde (MDA), and scavenging activities of superoxide anion (O2-) radical were measured by colorimetric method. RESULTS: The percentage of myolysis in the left and right atria of the control group were (53.6 +/- 11.8)% and. (58.5 +/- 9.2)% respectively, significantly higher than those of the sham operation group [(4.4 +/- 3.1)% and (4.1 +/- 2.9)% respectively, both P < 0.01]. The percentage of myolysis in the left and right atria of the probucol group were (12.3 +/- 3.2)% and (12.0 +/- 2.6)% respectively, both significantly lower than those of the control group (both P < 0.01). The protein expression of calpain I of the control group was significantly higher than that of the sham-operation group, and the protein expression of calpain I of the probucol group was significantly lower than that of the control group. The AF inducibility rate after pacing of the probucol group was 60%, significantly lower than that of the control group (92.9%, P < 0.01). The average AF duration time after pacing of the probucol group was (601 +/- 328) s, significantly shorter than that of the control group (1458 +/- 498) s. The indexes of oxidative stress in probucol group were lower than the level in control group. The MDA levels of the probucol group was (3.08 +/- 0.20) mmol/mg protein, significantly lower than that of the control group (4.15 +/- 0.23) mmol/mg protein). The anti-O2- and T-AOC level of the probucol group were 279 +/- 20 U/g protein and 30.5 +/- 1.3 nmol/mg protein, both significantly higher than those of the control group (215 +/- 16 U/g protein and 25.6 +/- 1.5 nmol/mg protein respectively, both P < 0.01). There were more sarcomere vacuolization and dissolution in atrial myocytes in the control group than in the sham operation group. And the pathohistological and ultrastructural changes of the probucol were lighter than those of the control group. CONCLUSION: Probucol prevents the pathohistological and ultrastructural changes in atrial myocardium by inhibiting calpain I expression, thus suppressing atrial structural remodeling, and preventing the induction and promotion of AF.