The rabbit enteropathogenic E. coli (rEPEC) strain RDEC-1 possesses a lifA homologue adjacent to the LEE pathogenicity island. To study the entire nucleotide sequence and biological function of lifA,the DNA sequence and biological function of RDEC-1 lifA were analysed with gene cloning,gene knock-out and in vivo virulence examination. The result showed that the entire coding sequence of the lifA of RDEC-1 shares nearly absolute homology with the lifA of human isolates. RDEC-1 lifA inhibited IL-2 expression in stimulated rabbit peripheral blood mononuclear cells. We further demonstrated significant reduction in fecal bacterial shedding by RDEC-1 derivative lifA mutant when compared with its parent strain. In a competitive study when rabbits were inoculated with a combination of the WT and the mutant, the WT was the predominant bacteria recovered from fecal samples, while fewer mutant bacteria were recovered. However,the lifA mutant is able to induce A/E type of lesions as efficient as the parent strain. The data provide direct evidence that lifA of rEPEC plays a role in immunomodulation and in in vivo colonization in the intestinal tract.

Objective To observe the protective effects of melatonin against spinal cord injury from seawater immersion in rabbits.Methods The 120 mature and health New Zealand White rabbits,weight range from 2.6 to 2.9kg,were randomly divided into four groups (30 each):control group,ethanol group,melatonin group (100mg/kg),methylPrednisolone group (30mg/kg).The rabbit model of spinal cord injury were built by modified Allen's method taking the 10th thoracic vertebra as a center,seawater immersion for 60 minutes,and then by grouping to give the appropriate treatment.After each group was given the corresponding treatment,six rabbits in each group were randomly selected at 1,6,12,24 and 48 hours five different time points.The neurological function scores of the rabbits were evaluated by Tarlov method,the spinal cord ofT9 to T.which were obtained from all the groups were used for further study,including immunohistochemical detection of apoptosis proteins:Bax,Bcl-2,neurofilament protein 200 (NF200) and in situ end labeling (TUNEL) method to detect spinal neuronal cell apoptosis.Results Within each observation time point,the Tarlov score was higher in melatonin group and methylprednisolone group compared with control group and ethanol group (P＜0.05),there was no significant difference between melatonin group and methylprednisolone group (P＞0.05).The expressions of Bcl-2 and NF200 were significantly higher in melatonin group and methylprednisolone group compared with control group and ethanol group,while Bax expression was significantly lower (P＜0.05).There were no significant difference between melatonin group and methylprednisolone group in the expression of three proteins (P＞0.05).The TUNEL-positive apoptotic cells were fewer in melatonin group and methylprednisolone group compared with control group and ethanol group (P＜0.05),and there was no significant difference between melatonin group and methylprednisolone group (P＞0.05).Conclusion Melatonin has protective effect against spinal cord injury from seawater immersion in rabbits,no difference in efficacy exists compare with methylprednisolone.

Objective:To analyze the clinical and imaging features of patients with spontaneous intracranial hypotension (SIH) combined with vestibulocochlear nerve symptoms, and explore the mechanism of vestibulocochlear nerve damage.Methods:From January 2014 to September 2019, 72 patients with SIH were chosen in our hospital; their clinical data were retrospectively analyzed; all patients underwent brain MR imaging. Based on vestibulocochlear nerve symptoms including dizziness, vertigo, tinnitus, aural fullness, and hearing loss, these patients were divided into two groups: 27 patients with vestibulocochlear nerve symptoms and 45 patients without vestibulocochlear nerve symptoms. The clinical and brain MR imaging features were compared between the two groups. The quantitative indexes of brain MR imaging were measured including the height of the pituitary gland, distances of the suprasellar cistern and prepontine cistern, distance from optic chiasm to pituitary fossa, mamillopontine distance, pontomesencephalic angle, and angle of transverse sinus. The qualitative signs of brain MR imaging were evaluated including pachymeningeal enhancement, subdural effusion or hematoma, effaced suprasellar cistern and prepontine cistern, decreased mamillopontine distance and pontomesencephalic angle, and transverse sinus distention.Results:In 27 SIH patients with vestibulocochlear nerve symptoms, the mean CSF pressure was (37.50±27.54) mmH 2O, and 22 patients (91.7%) presented with orthostatic headache. In 45 SIH patients without vestibulocochlear nerve symptoms, the mean CSF pressure was (39.00±26.91) mmH 2O, and 39 patients (95.1%) presented with orthostatic headache. As compared with SIH patients without vestibulocochlear nerve symptoms, the patients with vestibulocochlear nerve symptoms showed significantly lower height of the pituitary gland ( P<0.05). The positive rate of effaced suprasellar cistern in SIH patients with vestibulocochlear nerve symptoms was significantly decreased as compared with those without vestibulocochlear nerve symptoms ( P<0.05); there were no significant differences in other quantitative indexes and positive rates of qualitative signs between the two groups ( P>0.05). Conclusion:The decrease of pituitary height and effaced suprasellar cistern may be closely related to the pathogenesis of vestibulocochlear nerve symptoms in SIH patients.

Objective:To investigate the clinical characteristics and therapeutic efficacy of spontaneous intracranial hypotension (SIH) complicated with cerebral venous thrombosis (CVT).Methods:The clinical data of 4 patients with SIH complicated with CVT admitted to our hospital from March 2014 to April 2020 were retrospectively analyzed. And the clinical data of 35 patients with SIH complicated with CVT were included for summary analysis through literature retrieval (the databases included PubMed, CNKI and Wanfang; retrieval period was from database construction to December 31, 2020).Results:These 4 patients were with onset of orthostatic headache; one was with recurred orthostatic headache after relief, and the other 3 developed persistent headache and epileptic seizure; case 1 was with superior sagittal sinus and cortical vein thrombosis, case 3 was with superior sagittal sinus thrombosis, and other 2 patients were with isolated cortical vein thrombosis. Twenty-six documented cases demonstrated headache changes: 12 patients (46.15%) developed persistent headache, 12 patients (46.15%) showed orthostatic headache persistently, and 2 patients (7.69%) had disappeared headache. The most common new symptoms were epilepsy in 17 patients (48.57%) and limb weakness in 10 patients (28.57%). Totally, these 31 patients (4 patients from our hospital+27 patients from literature retrieval) had hemorrhage after treatment; the percentage of patients having hemorrhage changes in the 17 patients accepted anticoagulant therapy was significantly increased as compared with that in 14 patients accepted other treatments (7/17 vs. 1/14, P<0.05); there were no bleeding changes in 5 patients accepted epidural blood patch and anticoagulant therapy. Conclusions:The clinical features of SIH complicated with CVT are various, and the change of headache is not a reliable marker. In the course of SIH, it is necessary to be alert to the occurrence of CVT if there are new symptoms such as epileptic attack or limb weakness. The etiological treatment of SIH is essential and the hemorrhage risk after anticoagulant therapy should be concerned in patients with SIH complicated with CVT.

Objective:To investigate the characteristics of magnetic resonance myelography (MRM) and its application in the treatment of spontaneous intracranial hypotension (SIH).Methods:The clinical data, MRM characteristics, and treatment of 15 patients with SIH who underwent MRM examination in the First Affiliated Hospital of Zhengzhou University from August 2014 to August 2019 were retrospectively analyzed. According to treatment methods, nine patients were divided into conservative treatment group and six patients were divided into combined epidural blood patch treatment group. The gender, age, time interval from onset to MRM examination, cerebrospinal fluid pressure and MRM characteristics between the two groups were compared. SPSS 20.0 software was used for statistical description, and independent sample t-test was applied to compare the differences between groups. Results:All of the 15 cases reported orthostatic headache. Their cerebrospinal fluid pressure was (29.67±19.77, range 0-55) mmH 2O (1 mmH 2O=0.009 8 kPa), and onset-MRM interval was (33.07±24.22, range 7-90) days. The MRM characteristics were observed, including all 15 cases with periradicular leaks, four cases with anterior epidural fluid collections, six cases with posterior epidural fluid collections, and eight cases with high cervical (C 1-2 to C 2-3) retrospinal cerebrospinal fluid collections. There were 2 to 32 leak sites with an average of (10.20±7.87) sites. Among the 153 leak sites, 58(37.9%) sites were located at cervical vertebra, 77(50.3%) sites at thoracic vertebra, 18(11.8%) sites at lumbar vertebra, and 61(39.9%) sites at either the cervicothoracic junction (C 7-T 1 to T 1-2) or the upper thoracic region (T 2-3to T 6-7). Five patients responded well to one-time targeted autologous epidural blood patch on the basis of the location of the cerebrospinal fluid leakage. Besides, one patient improved with targeted epidural blood patch twice. There were no statistically significant differences in gender, age, onset-MRM interval, cerebrospinal fluid pressure, number and location of leak sites between the conservative treatment group and combined treatment group. Conclusions:The periradicular leaks of cerebrospinal fluid at cervical vertebra and thoracic vertebra are the most common feature of MRM in patients with SIH. MRM can identify the existence and location of cerebrospinal fluid leakage, assist in the diagnosis of SIH, and guide targeted epidural blood patch.