Clostridium difficile (C.difficile) infection is the leading cause of hospital-acquired diarrhea and pseudomembranous colitis.C.difficile-associated disease (CDAD) is mediated mainly by two bacterial toxins, TcdA and TcdB, which cause the diarrhea, as well as colitis and even intestinal necrosis.It has been indicated that level of C.difficile toxin is an important factor influencing the clinical phenotype of CDAD, however, the exact association between toxin and clinical phenotype remains unclear.In this article, we summarized the clinical phenotype of CDAD, the structure, function and regulatory mechanism of C.difficile toxin and discussed the relationship between C.difficile toxin and clinical phenotype, which may help to understand the pathogenic mechanism and provide possible therapeutic target for C.difficile infection.

Clostridium difficile( C. difficile)is a major nosocomial infection pathogen and the principal causative agent of antibiotic-associated diarrhea. The toxigenic C. difficile strains cause colonic injury and inflammation mainly by secreting enterotoxin A( TcdA)and cytotoxin B( TcdB). The severity of C. difficile associated disease( CDAD)is correlated to the toxin level during host infection. However,the toxigenic capacity of C. difficile varies widely among strains,which correlates with the gene regulation involved during toxin production. This article reviewed the regulatory mechanism of C. difficile toxin-associated pathogenic gene and anti-toxin treatment.

A chemiluminescence enzyme immunoassay based on magnetic microparicles (MmPsCLEIA) was developed to evaluate serum α-fetoprotein (AFP) in parallel with tramional colorimetric enzyme-linked immunsorbrnt assay (ELISA).A sestematic comparison between the MmPs-CLEIA and colorimetric ELISA concluded that the MPs-CLEIA exhibited fewer of immunoreagents,less total assay time,and better linearity,recovery,precision,senitivity and validity.AFP was detected in forty human serum samples by the proposed MPs-CLEIA and ELISA,and the results werecompared with commercial electrochemilunminescence immunoassay (ECLIA) kit.The correlation coefficient between MPs-CLEIA and ELISA was obtained with R2=0.6703; however,the correlation between MPs-CLEIA and ECLIA (R2=0.9582) was obviously better than that between colorimetric ELISA and ECLIA (R2=0.6866).

Glypican-3 (GPC3) is reported as a great promising tumor marker for hepatocellular carcinoma (HCC) diagnosis.Highly sensitive and accurate analysis of serum GPC3 (sGPC3),in combination with or instead of traditional HCC marker alpha-fetoprotein (AFP),is essential for early diagnosis of HCC.Biomaterial-functionalized magnetic particles have been utilized as solid supports with good biological compatibility for sensitive immunoassay.Here,the magnetic nanoparticles (MnPs) and magnetic microparticles (MmPs) with carboxyl groups were further modified with streptavidin,and applied for the development of chemiluminescence enzyme immunoassay (CLEIA).After comparing between MnPs- and MmPs-based CLEIA,MnPs-based CLEIA was proved to be a better method with less assay time,greater sensitivity,better linearity and longer chemiluminescence platform.MnPs-based CLEIA was applied for detection of sGPC3 in normal liver,hepatoeirrhosis,secondary liver cancer and HCC serum samples.The results indicated that sGPC3 was effective in diagnosis of HCC with high performance.

Glypican-3 （GPC3） is reported as a great promising tumor marker for hepatocellular carcinoma （HCC） diagnosis. Highly sensitive and accurate analysis of serum GPC3 （sGPC3）, in combination with or instead of traditional HCC marker alpha-fetoprotein （AFP）, is essential for early diagnosis of I-ICC. Biomaterial-functionalized magnetic particles have been utilized as solid supports with good biological compatibility for sensitive immunoassay. Here, the magnetic nanoparticles （MnPs） and magnetic microparticles （MmPs） with carboxyl groups were further modified with streptavidin, and applied for the development of chemiluminescence enzyme immunoassay （CLEIA）. After comparing between MnPs- and MmPs-based CLEIA, MnPs-based CLEIA was proved to be a better method with less assay time, greater sensitivity, better linearity and longer chemiluminescence platform. MnPs-based CLEIA was applied for detection of sGPC3 in normal liver, hepatocirrhosis, secondary liver cancer and HCC serum samples. The results indicated that sGPC3 was effective in diagnosis of HCC with high performance.

Objective:To observe effect of acupuncture combined with hypothermia therapy on MAPK/ERK pathway and apoptosis related factorsin rats suffered cerebral ischemia reperfusion and to explore underlying mechanisms.Methods:Middle cerebral artery ischemia model were established.Ninety SD rats were randomly assigned into a blank group,a control group,a model group,an acupuncture group,a mild hypothermia group,and an acupuncture with hypothermia group.After 72 h treatment,nervefunction defect scores were observed,and infarction area percent was detected by 2,3,5-triphenyl-2H-tetrazolium chloride (TTC) staining;expressions of Bcl-2 and Bax were examined by immunohistochemistry;apoptotic cells were detected by TUNEL assay;and expression levels of phospho-mitogen-activated protein kinase(p-MEK2) and phospho-extracellular signal regulated kinase 1/2 (p-ERK1/2) in the rats' hippocampus ischemic side were determined by Western blot.Results:In the rats of the model group,the neural function defect scores,the infarction area percent,the expression level of Bax,and apoptotic cells increased,while the level of Bcl-2 decreased significantly.The level of p-MEK2 and p-ERK1/2 increased obviously compared with the blank and control groups (P＜0.05 or P＜0.01).After treatment with acupuncture and hypothermia,the neural function defect scores,infarction area percent,and the level ofBax,apoptotic cells and the levels of p-MEK2 and p-ERK1/2 were significantly decreased,while the level of Bcl-2 in the treatment group was significantly elevated (P＜0.05 or P＜0.01) compared with the model group.Compared with the acupuncture group or the hypothermia group,the neural function defect scores and the levels of p-MEK2 and p-ERK1/2 in the acupuncture combined with hypothermia group were significantly reduced (P＜0.05 or P＜0.01).Conclusion:Acupuncture and hypothermia therapy can improve cerebral function,and reduce the cerebral injury through down-regulation of Bax level,and up-regulation of Bcl-2 level,which is related to reducing the levels of p-MEK2 and p-ERK1/2.The therapeutic effects on cerebral ischemia reperfusion injury for combination of acupuncture with hypothermia are better than those with single application of acupuncture or hypothermia.

Objective: To investigate the effect of acupuncture plus mild hypothermia on neurological function impairment score, cerebral infarct size and apoptosis-related factors in cerebral ischemia reperfusion injury (CIRI) rats.Methods: Sixty healthy male Sprague-Dawley (SD) rats were routinely reared for 1 week. Ten rats were randomly selected as the sham operation group and 10 rats as the blank control group, while the remaining 40 rats were subjected to preparing the middle cerebral artery occlusion (MCAO) model by modified filament occlusion method. The 40 MCAO rats were further randomly divided into a model group, an acupuncture group, a mild hypothermia group and an acupuncture plus mild hypothermia group, with 10 rats in each group. Rats in the sham operation group, the blank control group and the model group did not accept treatment except binding; rats in the acupuncture group received acupuncture treatment; rats in the mild hypothermia group received mild hypothermia treatment; rats in the acupuncture plus mild hypothermia group received acupuncture and mild hypothermia treatment. 72 h after the treatment, neurological function impairment score was performed; the infarct area ratio was determined by 2,3,5-tripheyl tetrazolium chloride (TTC) staining; apoptosis of brain cells was observed by TUNEL method; the expressions of Bcl-2, Bax and Caspase-3 were detected by immunohistochemistry.Results: Compared with the blank control group and the sham operation group, the neurological function impairment score, cerebral infarct area ratio, apoptosis, and the expressions of Bax and Caspase-3 in the model group were significantly increased, while the expression of Bcl-2 was significantly decreased, and there were significant between-group differences (allP<0.05). After the treatment, there were statistically significant differences among the treatment groups in the neurological function impairment score, cerebral infarct area ratio and apoptosis in the ischemic side of rats, as well as the expressions of Bcl-2, Bax and Caspase-3 (allP<0.05), and from the figures, tables and statistical analysis, it was found that a better tendency in the acupuncture plus mild hypothermia group than the acupuncture group or mild hypothermia group.Conclusion: Acupuncture plus mild hypothermia can protect the brain cells by improving neurological function impairment, decreasing cerebral infarct area ratio, reducing the number of apoptotic cells in the ischemic area and regulating the expressions of apoptosis related proteins to inhibit apoptosis.

Objective:To observe the protective effect of acupuncture plus mild hypothermia on brain tissues in rats with cerebral ischemia-reperfusion injury (CIRI), and the influence on protein expression levels of phosphorylated Raf-1, MEK-2 and ERK1/2 in the mitogen-activated protein kinase (MAPK)/extracellular regulated protein kinases (ERK) pathway, and to explore the mechanism of acupuncture plus mild hypothermia therapy for the ischemic stroke. Methods:Ninety Sprague-Dawley (SD) rats were randomly divided into a blank control group, a sham operation group, a model group, an acupuncture group, a mild hypothermia group and an acupuncture plus mild hypothermia group, 15 rats in each group. Except the rats in the blank control group, the remaining rats were used to prepare the middle cerebral artery occlusion (MCAO) models according to the modified occlusion method using lines, while only the occlusion lines were inserted without blocking the brain arteries of rats in the sham operation group. When the vital signs of rats were stable, rats in the blank control group did not receive any intervention; rats in the sham operation group and the model group received fastening without treatment; rats in the acupuncture group, the mild hypothermia group, and the acupuncture plus mild hypothermia group were treated with the corresponding therapeutic methods. 72 h later, observed neurologic injury score, evaluated infarction area ratio by 2,3,5-tripheyl tetrazolium chloride (TTC) staining, determined apoptosis by TUNEL assay, and measured the phosphorylated Raf-1, MEK-2 and ERK1/2 protein expression levels in rat ischemic hippocampal tissues by Western blot assay. Results: Compared with the blank control group and the sham operation group, after modeling, the neurologic injury score, infarction area ratio and apoptotic cells were increased, and phosphorylated Raf-1, MEK-2 and ERK1/2 protein expression levels were significantly increased in the model group; the differences were statistically significant (P<0.05 orP<0.01). Compared with the model group, after acupuncture or mild hypothermia therapy, neurologic injury score and infarction area ratio were decreased; apoptotic cells and phosphorylated Raf-1, MEK-2 and ERK1/2 protein expression levels were significantly decreased; the differences were statistically significant (P<0.05 orP<0.01). Compared with the acupuncture group, neurologic injury score and phosphorylated Raf-1, MEK-2 and ERK1/2 protein expression levels were decreased in the acupuncture plus mild hypothermia group; differences between the groups were statistically significant (P<0.05 or P<0.01). Compared with the mild hypothermia group, phosphorylated Raf-1, MEK-2 and ERK1/2 protein expression levels decreased in the acupuncture plus mild hypothermia group, and differences were statistically significant (P<0.01). Conclusion:Acupuncture or mild hypothermia therapy can improve neurologic injury, reduce infarction area and apoptosis, which brought about protective effect on the brain tissues, in the MCAO model. The protective effect of acupuncture plus mild hypothermia group is the strongest. The mechanism may involve the MAPK/ERK pathway, by reducing the phosphorylated Raf-1, MEK-2 and ERK1/2 protein expression levels.

Objective To evaluate the risk factors and sonographic findings of pregnancies complicated by placenta increta or placenta percreta. Methods Totally, 2219 cases were retrospectively analyzed from 20 tertiary hospitals in China from January 2011 to December 2015. The data were collected based on the original case records. All cases were divided into two groups, the placenta increta (PI) group (79.1％, 1755/2219) and the placenta percreta (PP) group (20.9％, 464/2219), according to the degree of placental implantation. The risk factors and sonographic findings of placenta increta or percreta were analyzed by uni-factor and logistic regression statistic methods. Results The risk factors associated with the degree of placental implantation were age, gravida, previous abortion or miscarriage, previous cesarean sections, and placenta previa (all P<0.05), especially, previous cesarean sections (χ2=157.961) and placenta previa (χ2=91.759). Sonographic findings could be used to predict the degree of placental invasion especially the boundaries between placenta and uterine serosa, the boundary between placenta and myometrium, the disruption of the placental-uterine wall interface and loss of the normal retroplacental hypoechoic zone(all P<0.01). Conclusions Previous cesarean sections and placenta previa are the main independent risk factors associated with the degree of placenta implantation. Ultrasound could be used to make a prenatal suggestive diagnosis of placenta accreta spectrum disorders.