[Role of blood markers in predicting the failure of prosthesis removal and antibiotic-loaded bone cement spacer implantation for treatment of periprosthetic joint infection]

Objective: To investigate the value of inflammation,coagulation and nutrition markers in predicting the failure of prosthesis removal and antibiotic-loaded bone cement spacer implantation for treatment of periprosthetic joint infection(PJI). Methods: A retrospective study was conducted on 70 patients who undertook prosthesis removal and antibiotic-loaded bone cement spacer implantation due to PJI from June 2016 to October 2020 in the Department of Orthopedics,Henan Provincial People's Hospital. There were 28 males and 42 females,aged (65.5±11.9) years (range: 37 to 88 years). Patients were divided into two groups as the successful group and the failed group depended on whether reinfection occurred after prosthesis removal and antibiotic-loaded bone cement spacer implantation at the last follow up. Patient demographics,laboratory values (C-reactive protein (CRP),erythrocyte sedimentation rate (ESR),ESR and CRP ratio (ESR/CRP),white blood cell count(WBC),platelet count(PLT),hemoglobin(HB),total lymphocyte count(TLC),albumin、fibrinogen(FIB),CRP and albumin ratio (CAR),prognostic nutritional index(PNI)),and reinfection rates were assessed. Comparison between groups was conducted by the independent sample t test or χ2test. Receiver operating characteristic (ROC) curve was plotted,and the area under the curve (AUC),optimal diagnostic threshold,sensitivity,and specificity were analyzed to predict the failure of prosthesis removal and antibiotic-loaded bone cement spacer implantation. Results: All patients were followed up for at least two years,and the follow-up time was (38.4±15.2) months (range: 24 to 66 months). Fifteen patients suffered failure after prosthesis removal and antibiotic-loaded bone cement spacer implantation,while the other 55 patients succeeded. The overall failure rate of prosthesis removal and antibiotic-loaded bone cement spacer implantation in PJI treatment was 21.4%. Level of preoperative CRP ((35.9±16.2)mg/L),PLT ((280.0±104.0)×109/L) and CAR (1.3±0.8) in successful group were lower than CRP ((71.7±47.3)mg/L),PLT ((364.7±119.3)×109/L) and CAR (2.5±2.0) in failed group (all P<0.05).Whereas,level of preoperative ESR/CRP (3.3±3.1), Albumin ((35.3±5.2)g/L) and PNI (43.6±6.2) in successful group were higher than ESR/CRP (1.6±1.4),Albumin ((31.3±4.8)g/L) and PNI (39.2±15.1) in failed group (all P<0.05). AUC of ROC curve,optimal threshold value,sensitivity and specificity of CRP,ESR/CRP, PLT, Albumin,CAR and PNI for the predicting failure of prosthesis removal and antibiotic-loaded bone cement spacer implantation were 0.776(95%CI:0.660 to 0.867),35.4 mg/L,86.7%,67.3%;0.725(95%CI:0.605 to 0.825),1.0,60.0%,78.2%;0.713(95%CI:0.593 to 0.815),253,93.3%,47.3%;0.721(95%CI:0.601 to 0.822),35.7,93.3%,49.1%;0.772(95%CI:0.656 to 0.863),1.1,86.7%,67.3%;0.706(95%CI:0.585 to 0.809),45.7,100%,41.8% respectively. Conclusion: In patients with PJI,CRP>35.4,ESR/CRP≤1.0 and CAR>1.1 could predict the failure of prosthesis removal and antibiotic-loaded bone cement spacer implantation.

[Progress in epidemiological research of norovirus infection]

With characteristics of high infectivity, diverse transmission routes and high variation, norovirus is the main pathogen of sporadic cases and outbreaks of acute gastroenteritis, resulting in a serious disease burden. This paper summarizes the latest progress in epidemiological research of norovirus infection from aspects of disease burden caused by acute gastroenteritis, virus variation and predominant strains, prevention and control measures, and immunization and vaccine development.

[Application of two RT-PCR methods for detection of norovirus in market-sold oysters and norovirus genetic characteristic analysis, a survey conducted in Beijing]

Objective: To evaluate the application of real-time RT-PCR and semi-nested RT-PCR in the detection of norovirus in oysters and analyzing the genetic characteristics of the isolates. Methods: Real-time fluorescent RT-PCR and semi-nested RT-PCR were used to detect norovirus GⅠ/GⅡ in fresh oysters collected from the markets in Beijing from November 2014 to October 2015. The detection rate of the parallel test was also analyzed. In addition, the reliability of semi-nested RT-PCR was evaluated by agreement rate and consistency test (Kappa value). The positive products of norovirus GⅠ/GⅡ capsid protein region gene by semi-nested RT-PCR were sequenced. Software BioEdit 7.0.9.0 was used for sequence alignment, and software Mega 6.0 was used to construct the evolutionary tree. Results: In 72 samples, the detection rate of norovirus was 31.94% (23/72) by real-time RT-PCR, 38.89% (28/72) by semi-nested RT-PCR and 48.61% (35/72) by parallel test. The coincidence rate of the two methods was 73.61%, a moderate degree (Kappa value =0.43). A total of 13 norovirus strains were successfully sequenced, and 11 strains (7 GⅡ.17 strains, 2 GⅡ. 4 Sydney_ 2012 strains, 1 GⅡ. 1 strain and 1 GⅡ. 21 strain) were obtained from norovirus positive samples by two RT-PCR methods, two strains (1 GⅡ. 17 strain and 1 GⅡ. 3 strain) were obtained from real-time RT-PCR negative samples which were positive for norovirus by semi-nested RT-PCR. The similarity between these strains and reference strains from diarrhea patients, environmental sewage, and shellfish products were 84.4% - 100.0%. Conclusions: The parallel test of norovirus in oysters by two RT-PCR methods can improve the detection rate and detect more genotypes. Norovirus strains in oysters were highly homologous with reference strains from diarrheal patients, environmental sewage, and shellfish products. Therefore, surveillance, prevention and control for norovirus should be carried out in people who have frequent contacts with oysters and related environments.

[Exploration on contamination and transmission of SARS-CoV-2 in imported cold chain aquatic products]

Contaminations of SARS-CoV-2 have been found for many times in imported cold chain aquatic products and their packaging materials in China. The purpose of this paper is to analyze the contamination status, sources and transmission risks of SARS-CoV-2 in imported cold chain aquatic products, and try to put forward relevant suggestions and strategies in order to provide evidence for the prevention and control of SARS-CoV-2 infection.

[Comparative study on metagenomics of esophageal flora in elderly and middle-aged esophageal squamous cell carcinoma patients]

Objective: To explore the flora characteristics and differences of esophageal tissues between elderly esophageal squamous cell carcinoma (ESCC) patients and young and middle-aged ESCC patients, so as to assist in studying the potential biomarkers of elderly ESCC patients. Methods: In this study, a retrospective study was adopted. 72 ESCC patients diagnosed in Taihe Hospital, Shiyan City, Hubei Province from July 2018 to July 2019 were selected, including 49 patients in the elderly group (≥ 60 years old, 40 males and 9 females), 23 patients in the young and middle-aged group (<60 years old, 21 males and 2 females). In the same period, 20 healthy persons without abnormal gastroscopy in endoscopy center were selected as the control group (aged 35-78 years old, median age 57 years old, 16 males and 4 females). The genomic DNA was extracted from the affected esophageal tissues of patients with ESCC and the middle esophageal samples of the control group. The V4 hypervariable region of bacterial 16SrRNA gene sequence was amplified. Illumina HiSeq sequencing technology was adopted. The flora characteristics of elderly, young and middle-aged ESCC patients was compared and analyzed. QIIME and Rstudio software were used to analyze the sequence data, and nonparametric Kruskal-Wallis test or Wilcoxon rank sum test were used for statistical methods. Results: Shannon index [5.17 (4.53, 5.95) vs. 4.79 (3.74, 5.97)], Simpson index [0.94 (0.91, 0.96) vs. 0.92 (0.83, 0.96)] and Chao1 index [343.55 (259.76, 570.59) vs. 329.16 (268.88, 648.00)] were similar in flora of two groups, and there was no significant difference (Z=-0.791, -1.057, -0.380, all P>0.05). There was no significant difference in β-diversity between the elderly group and the young and middle-aged group (PC1=19.14%, PC2=6.95%, P_PC1=0.67, P_PC2=0.42). At the phyla level, the top 5 phyla in abundance were as follows: Firmicutes, Bacteroidetes, Proteobacteria, Actinobacteria and Fusobacteria in the young and middle-aged group, while the top 5 phyla in abundance were as follows: Firmicutes, Bacteroidetes, Proteobacteria, Fusobacteria and Actinobacteria in the elderly group; the significant difference between the two groups was Fusobacteria (Q=0.596, P<0.05). At the genus level, the top 5 genera in the young and middle-aged group in abundance were as follows: Prevotella, Bacteroides, Streptococcus, Selenomonas and Veillonella. In the elderly group, Prevotella, Bacteroides, Streptococcus, Selenomonas and Haemophilus were the top 5 in abundance, and there were significant difference in Fusobacterium between the two groups (Q=0.938, P<0.05). PICRUSt function prediction showed that the abundance of Aminoacyl.tRNA.biosynthesis, Nucleotide.excision.repair, RNA.polymerase, Ribosome, Clavulanic.acid.biosynthesis, Photosynthesis and Photosynthesis. proteins in the elderly group were lower than those in the young and middle-aged group (all Q=0.734, P<0.05). Conclusion: There is no significant difference in α-diversity and β-diversity between elderly ESCC patients and young and middle-aged patients, but the abundance of Fusobacterium flora increased.

[Progress on genotyping of norovirus]

Norovirus are now recognized as one of the main pathogens causing acute gastroenteritis in both developed and developing countries. However, norovirus are easily mutated and recombined, and have many genotypes. In early studies, norovirus were amplified and identified by amino acid sequence of VP1 region. It was found that norovirus were easily mutated and recombined in or near the overlapping regions of polymerase and capsid. A two regions genotyping method was positively proposed internationally. Depending on the 2 times standard deviation standard method for two regions identification, norovirus polymerase regions can be divided into 10 gene groups and 76 genotypes including 2 tentative gene groups and 16 tentative genotypes. The VP1 region can be divided into 12 gene groups and 53 genotypes including 2 tentative gene groups and 5 tentative genotypes. However, the tentative gene groups and genotypes need to be further identified and reclassified. In this article, characteristics of norovirus sequences, principles of different genotyping methods, methods of sequence amplification, on-line genotyping tools and the latest studies in norovirus genotypes are reviewed and introduced.

[Sampling survey report on Chinese physicians' cognition of the guidelines on diagnosis and treatment of colorectal cancer]

Objective: To investigate and evaluate the mastery and recognition degree of Chinese clinicians on the 2015 edition of the Chinese Criteria for Diagnosis and Treatment of Colorectal Cancer in order to provide useful suggestions for updating and formulating diagnosis and treatment standards. Methods: Simple random sampling was used to conduct a questionnaire survey in 1500 colorectal cancer-related doctors in general hospitals and cancer hospitals from 115 cities in China. The study included the following guidelines: (1) Chinese Criteria for Diagnosis and Treatment of Colorectal Cancer (2015 edition); (2) Chinese Society of Clinical Oncology Colorectal Cancer Guidelines 2017 (CSCO 2017); (3) National Comprehensive Cancer Network (NCCN) Colon Cancer Guidelines 2017.v1; (4) European Society for Medical Oncology (ESMO) Rectal Cancer Guidelines. The survey was carried out in 2017 and 2019 respectively. In the first phase, the questionnaire included 4 dimensions (guideline cognition, detection and diagnosis, pathology and staging, treatment), and 1500 questionnaires were distributed. In the second phase, the questionnaire contained 3 dimensions (basic information, current treatment status of metastatic colorectal cancer, academic expectations), and 350 questionnaires were distributed. Case (%) was used to indicate the categorical variable data, and chi-square test was used for comparison between groups. P<0.05 indicated that the difference was statistically significant. Results: In the first phase, 1472 valid questionnaires were collected, and the questionnaire efficiency was 98.1% (1472/1500). In the second phase, 337 valid questionnaires were collected, and the questionnaire efficiency was 96.3% (337/350). In the survey of the first phase, doctors had some knowledge and compliance with various guidelines, but the most familiar one was the NCCN guidelines, accounting for 90.7% (1335/1472). In the dimension of detection and diagnosis, the overall correct rate was 64.1% (944/1472). The correct rate of doctors in the first-tier cities was 55.6% (148/266), which was lower than 59.1% (182/308) and 72.9% (369/506) in the second- and the third-tier cities, and the difference was statistically significant (χ(2)=42.140, P<0.001). More than 60.0% (883/1472) of doctors was clear about the specification requirements of the staging evaluation and pathological examination. However, in terms of rectal cancer local staging evaluation, the ratio of doctors who would choose rectal MRI in the first-tier cities was lower than that of those in other tier cities [51.5% (137/266) vs. 65.6% (202/308), 63.2% (320/506) and 61.2% (240/392)], and the difference was statistically significant (χ(2)=41.886, P<0.001). In the dimensions of staging evaluation and pathological examination, there were no statistically significant differences in cognition between general and specialist hospitals (P>0.05). In the treatment dimension, 79.8% (1175/1472) of doctors considered the preoperative treatment as a necessary option for patients with middle and low locally advanced (over cT3) rectal cancer. 46.3% (681/1472) of doctors, including 60.3% (433/718) of surgeons, and 31.4% (225/716) of physicians, had a vague idea that irinotecan could not be used for postoperative adjuvant treatment of colorectal cancer. In the survey of the second phase, 93.8% (316/337) of doctors approved potentially curative systemic (conversion) therapy, and 95.3% (321/337) of doctors followed the clinical guidelines in the treatment of metastatic colorectal cancer. Regarding academic expectations, the clinician's concern for surgery was more practical, and 79.2% (267/337) of doctors wanted to know the best options of conversion therapy for potentially curable metastatic colorectal cancer. In contrast, the clinician's concern for internal medicine was more exploratory, and 80.1% (270/337) of doctors focused on selecting targeted drugs and the sequence of treatment. Conclusions: This investigation has a preliminary understanding of the diagnosis and treatment of colorectal cancer in China. (1) There are many guidelines for doctors' reference, but doctors' understanding of domestic guidelines is not as good as NCCN guidelines. (2) The degree of understanding of the guidelines varies significantly among doctors in different cities. (3) The promotion of guidelines should focus on basic concepts and theories. (4) The detection, diagnosis, and treatment of colorectal cancer should be better trained and promoted. (5) The concept of conversion therapy for metastatic colorectal cancer is highly recognized.

[Analysis of pathogenic composition and clinical characteristics of viral acute gastroenteritis in children under five years old in Beijing]

Objective: To understand the epidemiological characteristics and clinical features of rotavirus-, norovirus-, adenovirus-and astrovirus-associ ated acute gastroenteritis in children under 5 years old in Beijing from Octorber, 2015 to March, 2017. Methods: In the intestinal clinic of 6 hospitals in 6 districts of Beijing, information and stool samples of the first 30 patients with acute gastroenteritis who are under the age of 5 years are collected monthly.Rotavirus, norovirus, adenovirus and astrovirus are identified by PCR.Descriptive epidemiological method was used to describe the epidemiological characteristics of diarrhea caused by rotavirus, norovirus, adenovirus and astrovirus in Beijing. One-way analysis of variance was used to analyze the Vesikari clinical severity score of of acute gastroenteritis caused by each virus. Unconditional logistic regression analysis was used to analysis the associated factors of clinical features. Results: Of the 2 052 samples, 709 (34.6%) were non-mixed infections: the positive rate of rotavirus, norovirus, adenovirus and astrovirus were 20.0%, 7.5%, 4.2% and 2.9%, respectively. A total of 135 cases (6.6%) were mixed infection. The mean and standard deviation of Vesikari clinical severity score was 8.0±3.1 for rotavirus associated acute gastroenteritis, which was significantly higher than norovirus (6.4±2.4, P<0.001), adenovirus (6.2±2.1, P<0.001) and astrovirus (6.1±2.0, P<0.001). The comparison of clinical features showed that compared with astrovirus, the children under 5 years old infected with rotavirus were more likely to have a diarrhea ≥5 days (OR=3.334), have vomiting ≥3 times within one day (OR=8.788), have vomiting≥1 day (OR=3.963), have a Vesikari clinical severity score ≥11 severe cases (OR=13.194). Norovirus infected cases were prone to have vomiting≥3 times in 1 day (OR=5.710).Adenovirus infected cases were prone to have a diarrhea≥5 days (OR=2.616). When using rotavirus as a reference, children under 5 years of age were less likely to develop fever≥38.4 ℃ after infection with norovirus (OR=0.397) or adenovirus (OR=0.280). Conclusions: The results of this study showed that the characteristics of acute gastroenteritis caused by different viruses are different. The clinical symptoms caused by rotavirus are more serious. Children under 24 months of age are at high risk of rotavirus infection. Effective preventive measures such as vaccination should be taken as soon as possible.

miR-144-3p increases radiosensibility of gastric cancer cells by targeting inhibition of ZEB1

PURPOSE

This study set out to probe into the effect and mechanism of miR-144-3p on radiosensitivity of gastric cancer (GC) cells.

METHODS

Cancer tissue and paracancerous tissue of GC patients admitted to our hospital were collected, their miR-144-3p expression was tested, GC cells were transfected, and survival and biological behavior of those cells under radiation were detected.

RESULTS

After detection, miR-144-3p expression was down-regulated in GC tissue, while ZEB1 was up-regulated. There was no remarkable difference in the survival fraction of cells in each group before receiving radiation, but that of tumor cells decreased obviously (p < 0.05) after radiation exposure. Survival fraction of cells overexpressing miR-144-3p or silencing ZEB1 decreased more obviously, while the inhibition of miR-144-3p or overexpressing ZEB1 was weaker. Biological behavior of cells under 6 Gy radiation was detected. It was found that miR-144-3p overexpression or silencing ZEB1 dramatically inhibited the proliferation activity of GC cells under 6 Gy radiation, increased the levels of pro-apoptotic Bax and caspase-3 proteins (p < 0.05) and decreased the anti-apoptotic protein Bcl-2 level (p < 0.05), resulting in an increase in the apoptosis rate of cells. miR-144-3p was confirmed to be ZEB1 targeting site by dual luciferase report. Moreover, rescue experiments prove that it can increase the radiosensitivity of GC cells by regulating ZEB1 expression.

CONCLUSION

miR-144-3p expression was down-regulated in GC, and it can increase the radiosensitivity of those cells by inhibiting ZEB1 expression.

[Analysis on influencing factors for acute gastroenteritis outbreaks caused by norovirus in Beijing, 2014-2018]

Objective: To analyze the influencing factors of acute gastroenteritis outbreaks caused by norovirus in Beijing from 2014 to 2018. Methods: Data of acute gastroenteritis events caused by norovirus in Beijing from April 2014 to March 2018 were collected. Unconditional logistic regression model was conducted to identify the risk factors of the outbreaks. Results: A total of 765 acute gastroenteritis epidemics caused by norovirus were reported in Beijing, in which 85.88% (657/765) were cluster events and 14.12% (108/765) were outbreaks. Among the outbreaks, 70.37% (76/108) were reported in 2017; 84.26% (91/108) were reported in winter and spring; 88.89% (96/108) were reported in kindergartens, primary or secondary schools; 81.48% (88/108) were through person-to-person transmission; 93.52% (101/108) were caused by norovirus GⅡ infection. The risk of outbreaks in suburban and out suburb area were 1.84 times (95%CI: 1.13-3.02) and 3.78 times (95%CI: 1.62-8.82) as high as that in urban area, respectively. The risks of outbreaks in primary, secondary schools and other institutions were 6.26 times (95%CI: 3.53-11.10), 14.98 times (95%CI: 6.23-36.01) and 8.71 times (95%CI: 3.07-24.71) as high as that in kindergartens, respectively. The risk of outbreak in which patients having lower hospital visiting rate than the median rate of all events was 2.29 times than that in the context of having higher hospital visiting rate (95%CI:1.42-3.68). The risk of foodborne outbreak was 14.55 times as high as that transmitted through person-to-person (95%CI: 3.15-67.07). Conclusion: Measures such as strengthening the prevention and control of norovirus outbreaks in suburbs, primary schools, secondary schools and other institutions, promoting patients to visit the hospital actively, improving the management of foodborne events and kitchen workers should be taken to reduce the incidence of acute gastroenteritis outbreaks caused by norovirus.

[Systematic review on the characteristics of acute gastroenteritis outbreaks caused by sapovirus]

Objective: To understand the epidemiological and etiological characteristics of outbreaks on acute gastroenteritis caused by sapovirus (SaV) worldwide. Methods: Literature about the outbreaks on acute gastroenteritis caused by SaV were retrieved from the databases including WanFang, CNKI, PubMed and Web of Science after evaluation. Time, geography, setting and population distributions of outbreaks, transmission mode, SaV genotype and clinical characteristics of the patients were analyzed. Results: A total of 34 papers about SaV were included, involving 146 outbreaks occurred between October 1976 and April 2016. In these papers, 138 outbreaks were reported on the related months. All these outbreaks occurred in northern hemisphere. SaV outbreaks occurred all year around, but mainly in cold season, the incidence was highest in December (25 outbreaks) and lowest in in August (2 outbreaks). Most outbreaks were reported by Japan, followed by Canada, the United States of America and the Netherlands. There were 141 outbreaks for which the occurring settings were reported, child-care settings were most commonly reported setting (48/141, 34.04%), followed by long-term care facility (41/141, 29.08%) and hospital (16/141, 11.35%). Clinical symptoms of 1 704 cases in 31 outbreaks were reported, with the most common symptom was diarrhea (1 331/1 704, 78.12%), followed by nausea (829/1 198, 69.20%), abdominal pain (840/1 328, 63.25%), vomiting (824/1 704, 48.36%) and fever (529/1 531, 34.53%). Genotypes of SaV were determined for 119 outbreaks. GⅠ(51/119, 42.86%) and GⅣ (45/119, 37.82%) were predominant. The outbreaks of GⅣ SaV increased suddenly in 2007, and the outbreaks of GⅠ SaV mainly occurred in 2008 and during 2011-2013. Conclusions: SaV outbreaks were reported mainly by developed countries, with most outbreaks occurred in cold season, in child-care settings and long term care facility. GⅠ and GⅣ were the most common genotypes of SaV. Prevention and control of SaV outbreak in China seemed relatively weak, and it is necessary to conduct related training and to strengthen the SaV outbreak surveillance in areas where service is in need.

The role of miR-320a and IL-1β in human chondrocyte degradation

Objectives

This study aimed to explore the role of miR-320a in the pathogenesis of osteoarthritis (OA).

Methods

Human cartilage cells (C28/I2) were transfected with miR-320a or antisense oligonucleotides (ASO)-miR-320a, and treated with IL-1β. Subsequently the expression of collagen type II alpha 1 (Col2α1) and aggrecan (ACAN), and the concentrations of sulfated glycosaminoglycans (sGAG) and matrix metallopeptidase 13 (MMP-13), were assessed. Luciferase reporter assay, qRT-PCR, and Western blot were performed to explore whether pre-B-cell leukemia Homeobox 3 (PBX3) was a target of miR-320a. Furthermore, cells were co-transfected with miR-320a and PBX3 expressing vector, or cells were transfected with miR-320a and treated with a nuclear factor kappa B (NF-κB) antagonist MG132. The changes in Col2α1 and ACAN expression, and in sGAG and MMP-13 concentrations, were measured again. Statistical comparisons were made between two groups by using the two-tailed paired t-test.

Results

Expression of miR-320a was elevated in OA cartilage tissues and chondrocytes, and in IL-1β-stimulated C28/I2 cells (p < 0.05 or p < 0.01). MiR-320a overexpression enhanced IL-1β-induced down-regulation of Col2α1 and ACAN and sGAG, and increased the IL-1β-induced overexpression of MMP-13 (p < 0.01). PBX3 was a direct target of miR-320a. PBX3 and MG132 co-transfection attenuated the effects of miR-320a on the expression of Col2α1, ACAN, sGAG and MMP-13(p < 0.01).

Conclusion

Overexpression of miR-320a might enhance IL-1β-induced cartilage degradation factors. These effects might be via targeting PBX3 and regulating NF-κB.

Cite this article: Y. Jin, X. Chen, Z. Y. Gao, K. Liu, Y. Hou, J. Zheng. The role of miR-320a and IL-1β in human chondrocyte degradation. Bone Joint Res 2017;6:–203. DOI: 10.1302/2046-3758.64.BJR-2016-0224.R1.

[Seasonality of clustering of fever and diarrhea in Beijing, 2009-2015]

Objective: To understand the seasonal distribution of the clustering of fever and diarrhea. Methods: Concentration degree and circular distribution methods were used to analyze the seasonal distribution of the clustering of fever and diarrhea in Beijing from 2009 to 2015. The information were collected from the Infectious Disease Surveillance Information System of Beijing. Results: The M values of the clustering of fever and diarrhea were 0.57 and 0.47. Circular distribution results showed that the clustering of fever and diarrhea angle dispersion index R values were 0.57 and 0.46 respectively, the sample average angle of Rayleigh' s test Z values were 414.14, 148.09 respectively (all P<0.01). The clustering of fever and diarrhea had seasonality. The incidence peak of fever was on October 13, and the epidemic period was during August 13-December 14. The incidence peak of diarrhea was on July 31, and the epidemic period was during May 20-October 11. Conclusion: The clustering of fever had obvious seasonality in Beijing, which mainly occurred in autumn and winter. The cluster of diarrhea had certain seasonality, which mainly occurred in summer and autumn.

A novel 31-bp indel in the paired box 7 (PAX7) gene is associated with chicken performance traits

1. A novel 31-bp indel polymorphism in intron 3 of the chicken paired box 7 (PAX7) gene was identified and genotyped in an F2 resource population of Gushi chicken crossed with Anka broiler to analyse its associations with chicken growth, carcass and meat quality traits. 2. Results showed that the 31-bp indel was significantly associated with body weight at 4, 6, 8, 10, 12 weeks of age and body size indices including shank length, shank girth, body slanting length at 8 and 12 weeks of age. Significant associations were found for carcass weight, semi-evisceration weight, evisceration weight, breast muscle fibre diameter, leg muscle fibre diameter, breast muscle fibre density, while no significant association with leg muscle fibre density was observed. 3. It was concluded that the 31-bp indel in intron 3 of the PAX7 gene was associated with chicken growth, carcass and meat quality traits where the 31-bp deletion had a negative effect on chicken growth and carcass traits and positive effect on meat quality traits.

First Report of Leaf and Sheath Spot Caused by Waitea circinata var. zeae on Paspalum vaginatum and Zoysia tenuifolia in China

Waitea circinata var. zeae was previously reported as the causal agent of leaf and sheath spot on Festuca arundinacea (1) and Panicum tennesseense (2) in the United States. In late May to mid-September 2013, a disease resembling leaf and sheath spot was observed on Paspalum vaginatum in fairways from several golf courses in Hainan Province, China. Affected plants initially had large yellow and brown spots on leaves and sheathes, then the whole plant turned yellowish-brown and eventually died. The same symptoms were also observed on a lawn established with Zoysia tenuifolia in Hainan University. Symptomatic leaves were surface sterilized in 1% hypochlorite for 1 min, rinsed with sterile water three times, and plated onto potato dextrose agar (PDA) amended with 0.01% gentamicin sulfate. Two Rhizoctonia-like fungal isolates were obtained from the diseased P. vaginatum (Isolate no. ML-WC1) and Z. tenuifolia (Isolate no. HNU-1) samples. After incubation on PDA for 1 week at 25°C, white mycelial colonies developed and eventually turned a salmon color with age. Small, white, spherical sclerotia (0.5 to 1 mm in diameter) were observed submerged throughout the agar media after incubation for 1 week and turned a reddish-brown color within 4 weeks. The two isolates were tentatively identified as W. circinata var. zeae based on these characteristics. The internal transcribed spacer (ITS) region of the ribosomal DNA gene was amplified and sequenced using primer pair ITS1/ITS4. The sequences of the two isolates (GenBank Accession Nos. KJ717943 and KJ717944) were more than 99% similar to W. circinata var. zeae (JQ688056 and JQ688059) sequences deposited in GenBank. To confirm pathogenicity, inocula were prepared by incubating autoclaved rye grains with strains ML-WC1 and HNU-1 for 2 weeks at 25°C. Ten colonized rye grains were uniformly spread around the crowns of 6-week-old P. vaginatum and Z. tenuifolia seedlings grown in 10-cm-diameter pots. Each isolate was placed in four separate pots and four control plants were treated with non-inoculated grain. All pots were covered with translucent plastic bags and placed in a greenhouse at 24 ± 2°C with a 12-h light/dark cycle. By 1 week post-inoculation, significant blighting of leaves and sheaths was observed, while non-inoculated plants showed no symptoms. W. circinata var. zeae was successfully re-isolated from symptomatic plants and confirmed by its Rhizoctonia-like mycelium and small, reddish-brown, spherical sclerotia on the PDA. Recently a related species, W. circinata var. circinata, causing brown ring patch on two cool-season grasses was reported in China (3). However, the isolates of W. circinata var. zeae were distinguished from W. circinata var. circinata base on ITS sequence data and morphological characters. To our knowledge, this is the first report of W. circinata var. zeae infecting P. vaginatum and Z. tenuifolia in China. References: (1) S. S. Martin, Jr. and L. T. Lucas. Plant Dis. 67:676, 1983. (2) N. A. Mitkowski. Plant Dis. 87:1006, 2003. (3) X. X. Ni et al. Plant Dis. 96:12, 2012.

A novel monoclonal antibody against human CD80 and its immune protection in a mouse lupus-like disease

Blockade of the interactions between CD28/CTLA-4 and their ligands, CD80 (B7, B7.1)/CD86 (B70, B7.2), is an attractive means to induce antigen-specific peripheral tolerance in autoimmune disease and organ transplantation. In this study, we generated and characterized a monoclonal antibody (Clone 4E5) against human CD80. 4E5 could recognize both human and mouse CD80 and suppress mixed lymphocyte reaction in vitro. To investigate their potency for clinical use, we further administrated 4E5 to a mouse lupus-like disease model (C57BL/J6) induced by Pristane. 4E5 could inhibit the immune response and attenuate the severity of lupus-like disease. The data showed 4E5 function and suggested that blockade of CD80/CD28 co-stimulatory signal pathway with 4E5 is a promising strategy to decelerate the progression of lupus-like disease and other autoimmune diseases.

WITHDRAWN: Spinal d-amino acid oxidase contributes to the pathogenesis of hyperalgesia in the rat formalin test

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Long-range correlations of density fluctuations in the Kerner-Klenov-Wolf cellular automata three-phase traffic flow model

Detrended fluctuation analysis (DFA) is a useful tool to measure the long-range power-law correlations in 1f noise. In this paper, we investigate the power-law dynamics behavior of the density fluctuation time series generated by the famous Kerner-Klenov-Wolf cellular automata model in road traffic. Then the complexities of spatiotemporal, average speed, and the average density have been analyzed in detail. By introducing the DFA method, our main observation is that the free flow and wide moving jam phases correspond to the long-range anticorrelations. On the contrary, at the synchronized flow phase, the long-range correlated property is observed.

Study on the shape memory effects of poly(L-lactide-co-epsilon-caprolactone) biodegradable polymers

The thermal properties, crystalline structure and shape memory effects of poly(L-lactide) (PLLA) and poly(L-lactide-co-epsilon-caprolactone) (PCLA) copolymers are systematically investigated by differential scanning calorimetry (DSC), X-ray diffraction (XRD) and tensile tests. The effects of the deformation strain on the shape recovery rate and recovery stress are also revealed. The polymers have the PLLA crystal and the amorphous phase, which are served as the fixed phase and reversible phase, respectively. The shape recovery rate and the recovery stress are significantly affected by the compositions and the deformation strain. With the increase of the deformation strain, the shape recovery rate decrease and higher shape recovery rate can be obtained in the polymers which have higher epsilon-CL content. However, the variation of recovery stress with the deformation strain is quite different and the maximum recovery stress of all polymers exceeds 3 MPa.

[Studies of the integration and expression of exogenes in transgenic rice obtained via particle bombardment transformation]

Various integration events from simple to complex have been found in transgenic elite rice varieties, which were co-transformed with bar and cecropin B gene by particle bombardment after system studies of the structure and expression of the transgene. It was displayed that there were one to seven insertion loci and one to ten copies of transgene in different transformants. No absolute correlation was found between the numbers of transgene copies and the gene expression. Different level expression of transgenes with similar insertion mode was also discovered. The expression cassette integrity and transcription frequency of selectable bar gene were more than non-selectable cecropin B gene, whereas gene silence in plants integrated with intact bar gene was found and higher expression level of cecropin B gene with 0.6 kb fragments degraded in terminator was deduced.

Insulin regulation of beta-cell function involves a feedback loop on SERCA gene expression, Ca(2+) homeostasis, and insulin expression and secretion

The insulin receptor signaling pathway is present in beta-cells and is believed to be important in beta-cell function. We show here that insulin directly regulates beta-cell function in isolated rodent islets. Long-term insulin treatment caused a sustained increase in [Ca(2+)](i) and enhanced glucose-stimulated insulin secretion in rat islets, but failed to increase insulin content. Chronic activation of insulin receptor signaling by IRS-1 overexpression in the beta-cell inhibited gene expression of SERCA3, an endoplasmic reticulum Ca(2+)-ATPase. Insulin gene transcription was stimulated by insulin receptor signaling and insulin mimetic compound (L-783 281) in a glucose- and Grb2-dependent manner. Thus, beta-cell SERCA3 is a target for insulin regulation, which implies that beta-cell Ca(2+) homeostasis is regulated in an autocrine feedback loop by insulin. This study identifies a novel regulatory pathway of insulin secretion at the molecular level with two main components: (1) regulation of intracellular Ca(2+) homeostasis via SERCA3 and (2) regulation of insulin gene expression.

Glucose regulation of glutaminolysis and its role in insulin secretion

Leucine or the nonmetabolized leucine analog +/- 2-amino-2-norbornane-carboxylic acid (BCH) (both at 10 mmol/l) induced biphasic insulin secretion in the presence of 2 mmol/l glutamine (Q2) in cultured mouse islets pretreated for 40 min without glucose but with Q2 present. The beta-cell response consisted of an initial peak of 20- to 25-fold above basal and a less marked secondary phase. However, BCH produced only a delayed response, while leucine was totally ineffective when islets were pretreated with 25 mmol/l glucose plus Q2. With Q2, 10 mmol/l BCH or leucine caused a nearly threefold increase, a twofold increase, or had no effect on cytosolic Ca2+ levels in islets pretreated for 40 min with 0, 5, or 15 mmol/l glucose, respectively. Thus, pretreatment of islets with high glucose inhibited BCH- and leucine-induced cytosolic Ca2+ changes and insulin release. Glucose decreased glutamine oxidation in cultured rat islets when BCH was present at 10 mmol/l, but not in its absence, with a lowest effective level of approximately 0.1 mmol/l, a maximum of 18-30 mmol/l, and an inhibitory concentration, 50%, of approximately 3 mmol/l. The data are consistent with the hypothesis that glucose inhibits glutaminolysis in pancreatic beta-cells in a concentration-dependent manner and hence blocks leucine-stimulated insulin secretion. We postulate that in the basal interprandial state, glutaminolysis of beta-cells is partly turned on because glutamate dehydrogenase (GDH) is activated by a decreased P-potential due to partial fuel depletion and sensitization to endogenous activators such as leucine. Additionally, it may contribute significantly to basal insulin release, which is known to be responsible for about half of the insulin released daily. The data explain "leucine-hypersensitivity" of beta-cells during hypoglycemia and contribute to the elucidation of the GDH-linked syndrome of hyperinsulinism associated with elevated serum ammonia levels. Thus, understanding the precise regulation and role of beta-cell glutaminolysis is probably central to our concept of normal blood glucose control.

Activation of the sphingomyelinase/ceramide signal transduction pathway in insulin-secreting beta-cells: role in cytokine-induced beta-cell death

Activation of the sphingomyelin/ceramide pathway may mediate interleukin-1-induced beta-cell death (Welsh, N: Interleuken-1beta-induced ceramide and diacylglycerol generation may lead to activation of the c-Jun NH2-terminal kinase and the transcription factor ATF-2 in the insulin-producing cell line RINm5F. J Biol Chem 271: 8307-8312, 1996). In this report, we have examined this pathway in more detail. Culture of beta-TC3 cells with 25 micromol/l ceramide analogs (N-acetyl- and N-hexanoylsphingosine) for 72 h did not significantly affect glucose- and carbachol-induced insulin secretion. Dihydroceramide (N-acetyl- or N-hexanoylsphinganine), a structurally similar analog, had no effect on agonist-induced secretion. However, ceramide analogs both time- and dose-dependently decreased cell viability, while the dihydroceramide analog had no effect. The ceramide effect on cell viability mimicked the effect of the cytokines TNF-alpha, IL-1beta, and IFN-gamma, reported stimulators of sphingomyelin hydrolysis. Cytokines, however, failed to stimulate sphingomyelin metabolism. Furthermore, using two different methods to quantitate ceramide, cytokines failed to cause an increase in beta-cell ceramide content versus unstimulated or time-matched vehicle controls. Taken together, these data suggest that although ceramide analogs mimic the cytotoxic effect of cytokines, activation of the sphingomyelin/ceramide signaling pathway is not involved in cytokine-induced beta-cell death.

Insulin receptor substrate 1-induced inhibition of endoplasmic reticulum Ca2+ uptake in beta-cells. Autocrine regulation of intracellular ca2+ homeostasis and insulin secretion

To understand the role of the insulin receptor pathway in beta-cell function, we have generated stable beta-cells (betaIRS1-A) that overexpress by 2-fold the insulin receptor substrate-1 (IRS-1) and compared them to vector-expressing controls. IRS-1 overexpression dramatically increased basal cytosolic Ca2+ levels from 81 to 278 nM, but it did not affect Ca2+ response to glucose. Overexpression of the insulin receptor also caused an increase in cytosolic Ca2+. Increased cytosolic Ca2+ was due to inhibition of Ca2+ uptake by the endoplasmic reticulum, because endoplasmic reticulum Ca2+ uptake and content were reduced in betaIRS1-A cells. Fractional insulin secretion was significantly increased 2-fold, and there was a decrease in betaIRS1-A insulin content and insulin biosynthesis. Steady-state insulin mRNA levels and glucose-stimulated ATP were unchanged. High IRS-1 levels also reduced beta-cell proliferation. These data demonstrate a direct link between the insulin receptor signaling pathway and the Ca2+-dependent pathways regulating insulin secretion of beta-cells. We postulate that during regulated insulin secretion, released insulin binds the beta-cell insulin receptor and activates IRS-1, thus further increasing cytosolic Ca2+ by reducing Ca2+ uptake. We suggest the existence of a novel pathway of autocrine regulation of intracellular Ca2+ homeostasis and insulin secretion in the beta-cell of the endocrine pancreas.

Phospholipase pathway in Alzheimer's disease brains: decrease in Galphai in dorsolateral prefrontal cortex

There is substantial evidence that G-protein-associated signaling pathways in the brain are altered in Alzheimer's disease (AD). Using quantitative immunoblotting we find a significant decrease in Galphai levels in every AD case examined compared to controls (mean Galphai level in AD was 43.5+/-7.4% of control). Galphao levels were slightly decreased, but Galphaq and betagamma were normal. Phospholipase C-beta1, but not gamma1, levels were also decreased. Total phospholipase C activity and ceramide levels were not changed. Thus, in AD, there is impairment in the Galphai-associated signaling pathway in neurons.

Mechanisms of spontaneous cytosolic Ca2+ transients in differentiated human neuronal cells

We have studied Ca2+ homeostasis in a unique model of human neurons, the NT2N cell, which differentiates from a human teratocarcinoma cell line, NTera2/C1.D1 by retinoic acid treatment. When perifused with Krebs-HEPES buffer containing 2.5 mM CaCl2, fura-2 loaded NT2N cells produced spontaneous cytosolic Ca2+ oscillations, or Ca2+ transients. These cytosolic Ca2+ transients were not blocked by antagonists of glutamate (6-cyano-7-nitroquinoxaline-2,3-dione and D(-)-2-amino-5-phosphonopentanoic acid) or muscarinic (atropine) receptors. Omission of extracellular Ca2+ completely abolished Ca2+ oscillations and decreased the average Ca2+ level from 106 +/- 14 nM to 59 +/- 8 nM. Addition of the L-type Ca2+ channel blocker nifedipine (1 or 10 microM) or of the N-type inhibitor omega-conotoxin GVIA (5 microM) significantly, although incompletely, suppressed Ca2+ oscillations, while omega-conotoxin MVIIC (5 microM), a selective antagonist of P- and Q-channels, had no effect. Ni2+, at 100 microM, a concentration selective for T-type channels, did not inhibit Ca2+ transients. Non-specific blockage of Ca2+ channels by higher concentrations of Ni2+ (2-5 mM) or Co2+ (1 mM) abolished Ca2+ oscillations completely. The endoplasmic reticulum Ca2+-ATPase inhibitor, thapsigargin (1 microM), slightly decreased Ca2+ oscillation frequency, and induced a small transitory increase in the average cytosolic Ca2+ concentration. The mRNAs of L- (alpha1D subunit) and N-type (alpha1B subunit) Ca2+ channel were present in NT2N cells, while that of a T-type Ca2+ channel (alpha1-subunit) was not present in the NT2N cells as shown by reverse transcription-polymerase chain reaction. In conclusion, NT2N neuronal cells generate cytosolic Ca2+ oscillations mainly by influx of extracellular Ca2+ through multiple channels, which include L- and N-type channels, and do not require activation of glutamate or muscarinic receptors.

Retinoic acid induction of calcium channel expression in human NT2N neurons

Ca2+ channel expression and regulation of intracellular Ca2+ homeostasis were studied during retinoic acid (RA)-induced differentiation of the human teratocarcinoma cell line Ntera 2/C1.D1 (NT2- cells) into NT2N neurons, a unique model of human neurons in culture. The cytosolic Ca2+ level of undifferentiated NT2- cells was low (75 +/- 5 nM) and stable under basal conditions, and it was only marginally decreased (by 9%) upon removal of extracellular Ca2+. After 10 microM RA treatment, NT2- cells were irreversibly differentiated into a phenotype of neuron-like NT2N cells. Cytosolic Ca2+ level of NT2N neurons was higher (106 +/- 14 nM) than that of NT2- cells and spontaneously fluctuated (0.208 +/- 0.038 transients/min) under basal conditions. Although K+ increased 86Rb fluxes in both NT2- cells and NT2N neurons, it only increased cytosolic Ca2+ level in NT2N neurons. The K+-induced increase in cytosolic Ca2+ in NT2N neurons was antagonized by 0.1-10 microM nifedipine or verapamil, 5 microM omega-CgTx GVIA, but not by 1 microM omega-agatoxin IVA, 1 microM omega-agatoxin TK, 1 microM FTX-3.3, or 100 microM Ni+ implicating L- and N-type voltage-dependent Ca2+ channels. In L- and N-type channels, but not in P- and Q-types, mRNAs were expressed in NT2N neurons as well as NT2- cells. Quantitative analysis of L- and N-type Ca2+ protein levels showed major differences between NT2- cells and NT2N neurons. In NT2- cells, N-type Ca2+ channels were undetectable while L-type channels levels were fivefold lower compared to NT2N neurons. Our findings show that L- and N-type channels are expressed during differentiation of NT2- cells into neurons, and that these voltage-dependent Ca2+ channels have a major role in regulating intracellular Ca2+ homeostasis and neuronal excitability.

Regulation of amyloid precursor protein secretion by glutamate receptors in human Ntera 2 neurons

The amyloid precursor protein (APP) can be cleaved by a beta-secretase to generate a beta-amyloid peptide, which has been implicated in the pathogenesis of Alzheimer's disease. However, APP can also be cleaved by an alpha-secretase to form a non-amyloidogenic secreted form of APP (APP-S). APP-S secretion can be physiologically regulated. This study examined the glutamatergic regulation of APP in the human neuronal Ntera 2 (NT2N) cell line. Metabotropic glutamate receptor subtypes 1alpha/beta and 5alpha were identified in the NT2N neurons by reverse transcription-polymerase chain reaction. Stimulation of these phosphatidylinositol-linked receptors with glutamate or specific receptor agonists resulted in a dose- and time-dependent increase in the secretion of the amyloid precursor protein (APP-S), measured by the immunoprecipitation of APP-S from the medium of [35S]methionine-labeled NT2N neurons. The glutamate-induced APP-S secretion was maximal at 30 min and at a concentration of 1 mM glutamate. Glutamate-induced APP-S secretion required activation of phospholipase C, which resulted in inositol 1, 4,5-trisphosphate production, as shown by the rapid glutamate-induced accumulation of inositol 1,4,5-trisphosphate. Glutamate also caused an increase in intracellular Ca2+. The protein kinase C activator phorbol 12-myristate 13-acetate, a phorbol ester, as well as 1-oleoyl-2-acetoyl-3-glycerol, a cell-permeable diacylglycerol analog, also stimulated APP-S secretion. These findings suggest that APP-S secretion from NT2N neurons can be regulated by the activation of phosphatidylinositol-linked metabotropic glutamate receptor signaling pathway.

Cytotoxic effect of beta-amyloid on a human differentiated neuron is not mediated by cytoplasmic Ca2+ accumulation

The effects of synthetic beta-amyloid (A beta1-42) on cell viability and cellular Ca2+ homeostasis have been studied in the human neuron-like NT2N cell, which differentiates from a teratocarcinoma cell line, NTera2/C1.D1, by retinoic acid treatment. NT2N viability was measured using morphological criteria and fluorescent live/dead staining and quantified using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide metabolism. A beta1-42 dose-dependently caused NT2N cell death when it was present in the cell culture for 14 days but had no effect on viability when it was present for 4 days. The lowest effective concentration was 4 microM, and the strongest effect was produced by 40 microM. Control NT2N cells produced spontaneous cytosolic Ca2+ oscillations under basal conditions. These oscillations were inhibited dose-dependently (0.4-40 microM) by A beta1-42 that was present in the cell culture for 1 or 4 days. Ca2+ wave frequency was decreased from 0.21 +/- 0.02 to 0.05 +/- 0.02/min, amplitude from 88 +/- 8 to 13 +/- 4 nM, and average Ca2+ level from 130 +/- 8 to 58 +/- 3 nM. The Ca2+ responses to 30 mM K+ and 100 microM glutamate were not different between control and A beta-treated cells. Thus, the results do not support the hypothesis that cytosolic early Ca2+ accumulation mediates A beta-induced NT2N cell death.

Eicosapentaenoic acid (C20:5) augments glucose-induced insulin secretion from beta-TC3 insulinoma cells

There has been a large amount of recent literature suggesting that omega-3 unsaturated fatty acids found in fish oils should be incorporated into the diet for the purpose of decreasing serum cholesterol levels. Inclusion of these fatty acids in the diet has been shown to decrease total serum cholesterol as well as low-density lipoprotein cholesterol. Some of these trials have been complicated by the fact that many of the subjects are afflicted with non-insulin-dependent diabetes mellitus. Unfortunately, the effects of omega-3 unsaturated fatty acids on insulin secretion have not been well characterized. In this study, we have examined the effect of a common omega-3 unsaturated fatty acid, eicosapentaenoic acid (C20:5), on insulin secretion. Using the beta-TC3 insulinoma cell line as a model system for studying insulin exocytosis, C20:5 selectively potentiated glucose-induced insulin secretion. At the same concentration at which it significantly increased glucose-induced insulin secretion, C20:5 did not affect glucose metabolism or intracellular free calcium concentrations. C20:5 also augmented potassium-induced insulin secretion. These data suggest that C20:5, an abundant omega-3 unsaturated fatty acid, acts to augment insulin secretion in a glucose-dependent manner.

[Investigation of cervical Chlamydia trachomatis infection in gynecologic outpatients]

A group of 662 women in our gynecologic OPD were screened for Chlamydia trachomatis with direct immunofluorecence monoclonal antibody (DFA) staining technique. Their age distribution ranged from 16 to 60 years old. The overall positivity rate was 26.3%. Of the 269 pregnant women, 64 cases were found to have Chlamydia trachomatis infection, an infection rate of 23.74%. There was no statistically significant difference of infection rates among age groups. In the positive group, however, the rate of infertility was 25.43%, much higher than that in the negative group (12.88%, P < 0.01). And there was no statistical significance of infection rates between patients taking contraception and those did not. A positive correlation existed between the degree of cervicitis and the Chlamydia trachomatis infection.

The role of protein kinase-C in signal transduction through vasopressin and acetylcholine receptors in pancreatic B-cells from normal mouse

The role of protein kinase-C (PKC) in the potentiation of insulin release by arginine vasopressin (AVP) and acetylcholine (ACh) was investigated with normal mouse islets. The islets were submitted to a short term (30-min) or long term (22-h) treatment with phorbol 12-myristate 13-acetate (PMA) to stimulate acutely or down-regulate PKC before being stimulated by AVP or ACh. Control islets were treated with the inactive 4 alpha-phorbol 12,13-didecanoate. In the presence of 15 mM glucose and 2.5 mM Ca2+, AVP and ACh stimulated inositol phosphate (IP) formation, increased cytoplasmic Ca2+ (Cai2+), and potentiated insulin release. These effects were greater with ACh than with AVP, in particular on Cai2+, which was scarcely affected by AVP. In the absence of extracellular Ca2+, only ACh induced a short-lived increase in Cai2+ and insulin. Acute treatment with PMA in the presence of extracellular Ca2+ strongly increased insulin release in spite of a marked lowering of Cai2+. Under these conditions, the effects of AVP and ACh on IP production and Cai2+ were practically abolished, and only ACh transiently increased insulin release. In the absence of Ca2+, the small mobilization of Cai2+ by ACh triggered a peak of insulin, whereas a similar mobilization of Cai2+ by AVP was ineffective on insulin. After long term treatment of the islets with PMA, AVP normally increased IP formation, but did not affect insulin release. The effect of ACh on IP was still inhibited. However, ACh produced a marked transient increase in Cai2+, with a small transient release of insulin. The releasing effect of ACh was also inhibited in the absence of Ca2+. In conclusion, PKC plays a dual role in the B-cell responses to ACh and AVP. Its activation is necessary for the sustained potentiation of insulin release that both agents produce. This effect probably results from a sensitization of the secretory machinery to Cai2+, the triggering signal. PKC also exerts a negative feedback control on the signal transduction mechanisms involving phospholipase-C, but the ACh and AVP responses are not equally affected by this feedback.

Multisite control of insulin release by glucose

Glucose controls insulin release by beta-cells at two sites at least. By controlling the membrane potential, it controls the influx of Ca2+ and the rise in cytoplasmic Ca2+ which triggers exocytosis. At this level, the principal targets of glucose are the K(+)-ATP channels whose activity may be modulated by changes in the ATP/ADP ratio. A second, newly identified, mechanism of regulation is independent of changes in beta-cell membrane potential and of changes in Cai2+. It is not sufficient to induce insulin release, but serves to increase the response. This appears to be achieved through an amplification of the effectiveness of Cai2+ on the secretory process and may also depend on the changes in energy state of beta-cells.

Arginine vasopressin and oxytocin effects in mouse pancreatic beta-cells. Receptors involved in stimulation of insulin release

Recently AVP and OT were suggested to increase insulin release by stimulating phosphoinositide metabolism in pancreatic beta-cells. In this study, mouse islets were used to identify the receptors involved in the effects of AVP and OT. Both agents caused concentration-dependent (0.1 nM to 10 microM) increases in insulin release and IP levels. The potencies of AVP and OT were similar, and their maximal effects were not additive. Synthetic agonists selective for AVP (V1) and OT receptors in other tissues were equipotent with the natural agonists on insulin release and almost equipotent on IPs. Antagonists selective for V1 and OT receptors inhibited both types of effects with a potency that varied with the nature of the agonist. Both AVP and OT were approximately 10-fold potent on insulin release (EC50 approximately 2 nM) than on IPs (EC50 approximately 25 nM). Moreover, the antagonists more readily inhibited the effects of all agonists on IPs than on insulin release. Pancreatic beta-cells may possess either a single type of receptor that is distinct from classic V1 or OT receptors, but is closer to the latter, or both V1 and OT receptors coupled to common effectors. The acceleration of phosphoinositide turnover might not be the sole mechanism involved in the stimulation of insulin release by AVP and OT.

Mechanisms by which glucose can control insulin release independently from its action on adenosine triphosphate-sensitive K+ channels in mouse B cells

Glucose stimulation of insulin release involves closure of ATP-sensitive K+ channels (K(+)-ATP channels), depolarization, and Ca2+ influx in B cells. However, by using diazoxide to open K(+)-ATP channels, and 30 mM K to depolarize the membrane, we could demonstrate that another mechanism exists, by which glucose can control insulin release independently from changes in K(+)-ATP channel activity and in membrane potential (Gembal et al. 1992. J. Clin. Invest. 89:1288-1295). A similar approach was followed here to investigate, with mouse islets, the nature of this newly identified mechanism. The membrane potential-independent increase in insulin release produced by glucose required metabolism of the sugar and was mimicked by other metabolized secretagogues. It also required elevated levels of cytoplasmic Cai2+, but was not due to further changes in Cai2+. It could not be ascribed to acceleration of phosphoinositide metabolism, or to activation of protein kinases A or C. Thus, glucose did not increase inositol phosphate levels and hardly affected cAMP levels. Moreover, increasing inositol phosphates by vasopressin or cAMP by forskolin, and activating protein kinase C by phorbol esters did not mimic the action of glucose on release, and down-regulation of protein kinase C did not prevent these effects. On the other hand, it correlated with an increase in the ATP/ADP ratio in islet cells. We suggest that the membrane potential-independent control of insulin release exerted by glucose involves changes in the energy state of B cells.

Glucose- and concentration-dependence of vasopressin-induced hormone release by mouse pancreatic islets

The effects of arginine-vasopressin (AVP) on hormone release by the endocrine pancreas have been studied with incubated islets from normal mice. A wide range of AVP concentrations (1 pM-100 nM) were tested in the presence of various glucose concentrations. AVP did not affect somatostatin release in a glucose-free medium but increased it in the presence of all tested glucose concentrations (3-30 mM). The lowest effective concentration was 1 mM and the effect was not yet maximal at 100 nM AVP. AVP markedly increased glucagon release in the absence of glucose. Its effect was attenuated but not abolished when glucagon release was inhibited by glucose. Surprisingly, the attenuation of the effect of AVP was stronger in 3-10 mM than in 15-30 mM glucose. The lowest effective concentration was 1 nM and the effect was not yet maximal at 100 nM AVP. AVP was ineffective on basal insulin release (0, 3 and 7 mM glucose), but potentiated the effect of 10, 15 and 30 mM glucose. The lowest effective concentration was 0.1-1 nM AVP and the maximal effect was produced by 10-100 nM AVP. The results suggest a direct action of AVP on each of the three islet cell types which display a roughly similar sensitivity to the peptide. This sensitivity is too low to make islet cells a possible target for circulating AVP under physiological conditions. On the other hand, the presence of AVP in the pancreas suggests that it might be involved in the peptidergic control of islet function.

Vanadate stimulation of insulin release in normal mouse islets

The effects of vanadate (Na3VO4) on pancreatic B-cell function were studied in normal mouse islets. Vanadate did not affect basal insulin release but potentiated the effect of 7-30 mM glucose at concentrations of 0.1-1 mM. This effect was progressive and slowly reversible. It was abolished by omission of extracellular Ca2+ but unaffected by blockers of adrenergic or muscarinic receptors. Comparison of the changes in membrane potential, 86Rb efflux and 45Ca efflux that vanadate and ouabain produced in B-cells made it possible to exclude the hypothesis that vanadate increases insulin release by blocking the sodium pump. Vanadate was also without effect on cAMP levels. On the other hand, it markedly changed the characteristics of the Ca(2+)-dependent electrical activity and of the oscillations of cytoplasmic Ca2+ recorded in B-cells stimulated by 15 mM glucose. In the steady state, Ca2+ influx was increased by vanadate, and this resulted in a rise in cytoplasmic Ca2+. The exact mechanisms underlying these changes could not be established but a blockade of K channels was excluded. In the presence of LiCl, vanadate markedly increased inositol phosphate levels in islet cells. This effect was attenuated but not suppressed by omission of Ca2+. A small increase in inositol bisphosphate was still produced by vanadate in the absence of LiCl. These results suggest that vanadate both stimulates phosphoinositide breakdown and inhibits inositol phosphate degradation. In conclusion, vanadate does not induce insulin release, but markedly potentiates the stimulation by glucose. This property is not due to an inhibition of the sodium pump or to a rise in cAMP concentration. It results from a complex interplay between changes in B-cell membrane potential, phosphoinositide metabolism and Ca2+ handling.

Mechanisms of the stimulation of insulin release by oxytocin in normal mouse islets

Oxytocin (OT) produced a dose-dependent increase in somatostatin, glucagon and insulin release by isolated mouse islets. A small effect on somatostatin release was observed with 0.1 nM-OT, but 1-10 nM-OT was required to affect A- and B- cells significantly. The effects of OT on somatostatin and glucagon release were similar in the presence of 3 mM- and 10 mM-glucose. No change in insulin release was produced by OT in 3 mM-glucose, but a stimulation was still observed in the presence of a maximally effective concentration of glucose (30 mM). The increase in insulin release produced by OT (in 15 mM-glucose) was accompanied by small accelerations of 86Rb and 45Ca efflux from islet cells. Omission of extracellular Ca2+ accentuated the effect of OT on 86Rb efflux, attenuated that on 45Ca efflux, and abolished that on release. OT never inhibited 86Rb efflux. It did not affect the resting potential of B-cells, but slightly increased the Ca2(+)-dependent electrical activity induced by 15 mM-glucose. OT did not affect cyclic AMP levels, but increased inositol phosphate levels in islet cells. It is suggested that the amplification of glucose-induced insulin release that OT produces is due to a stimulation of phosphoinositide metabolism, and presumably an activation of protein kinase C, rather than to a change in cyclic AMP levels or a direct action on the membrane potential. Since OT is present in the pancreas, it is possible that it exerts a neuropeptidergic control of the islet function.

Comparison of effects of magnesium valproate and sodium valproate on the action potential of isolated papillary muscle from guinea pigs and dogs

A comparison of the effects of magnesium valproate (MV) and sodium valproate (SV) on the action potential of isolated papillary muscle from guinea pigs and dogs was made in this study. The results in both animals were as follows: MV and SV induced a slight reduction of slope plateau of action potential and prolongation of action potential duration (APD). What is more, APD50 and APD90 were prolonged significantly, thus the ratio of APD90/APD25 was increased. The effective refractory period (ERP) was prolonged significantly. MV or SV showed no effects on action potential amplitude, overshoot, resting potential and phase 0 upstroke velocity. The above results suggested that MV and SV might play an antiarrhythmic role and that their effects were analogic. The mechanism of MV and SV inducing significant prolongation of APD50, APD90, and ERP, might be closely related to the slow-down of the velocity of K+ efflux during plateau and repolarization of phase 3 by radical of valproate and the slow-down of velocity of K+ efflux of repolarization of phase 3 in particular. These results showed that there was no difference in SV and MV action on guinea pigs and dogs.

Mechanisms of the stimulation of insulin release by arginine-vasopressin in normal mouse islets

The mechanisms by which arginine-vasopressin (AVP) affects pancreatic B-cell function were studied in normal mouse islets. AVP produced a dose-dependent (0.1-1000 nM; EC50 approximately 1-2 nM) amplification of glucose-induced insulin release. This amplification was of slow onset and reversibility. AVP was ineffective when the concentration of glucose was less than 7 mM, but was still very effective in 30 mM glucose. The increase in insulin release produced by AVP was accompanied by small accelerations of 86Rb and 45Ca efflux from islet cells. Omission of extracellular Ca2+ accentuated the effect of AVP on 86Rb efflux, attenuated that on 45Ca efflux, and abolished that on release. Under no condition did AVP inhibit 86Rb efflux. AVP did not significantly affect cAMP levels, but increased inositol phosphate levels in islet cells, even in the absence of extracellular Ca2+. AVP did not affect the membrane potential in unstimulated B-cells and augmented glucose-induced electrical activity only slightly. This was not due to a direct action on ATP-sensitive K+ channels as revealed by patch-clamp recordings (whole cell and outside-out patches). In conclusion, AVP is not an initiator of insulin release, but it potently amplifies glucose-induced insulin release in normal mouse B-cells. This effect involves a stimulation of phosphoinositide metabolism, and presumably an activation of protein kinase C, rather than a change in cAMP levels or a direct control of the membrane potential.

[Surgical treatment of thyroid cancer]

From 1957 to 1980, 151 patients with thyroid cancer were treated by surgery in our hospital. Papillary adenocarcinoma was predominant (53%), followed by undifferentiated (23%) and follicular types (20%). The diagnosis, established only according to the clinical symptoms and 131I scan, gave a high misdiagnosis rate (44%). The misdiagnosis could also be made on the operation. The causes are: 1) limitation of 131I scan in diagnostic specificity; 2) lack of vigilance for thyroid cancer; 3) neglecting the subtle histological changes during the operation; 4) failure in submitting the frozen section. Fine needle aspiration cytology is emphasized in order to improve the preoperative diagnostic accuracy. Lobectomy and modified neck dissection are the most common modalities of operation for papillary and follicular cancers. The 5 year survival rates were 74% and 50% respectively. Modified neck dissection increased the 5 year survival up to 85%. Undifferentiated cancer could be treated, at best, by palliative treatment. The authors believe that a rational radical operation should be performed according to the pathological type, biological behavior and stage of the lesion, followed by adjuvant endocrine and/or isotope therapy, which could improve the treatment result.