Résumé
Objective@#To investigate the imaging features of cerebral small vessel disease(SVD) in systemic lupus erythematosus(SLE) patients with impaired renal function and their related risk factors.@*Methods@#Seventy-six SLE patients and forty age- and sex-matched healthy controls were recruited, and SLE patients were divided into the impaired renal function group [estimated glomerular filtration rate (eGFR) <90 ml/(min·1.73 m2)] (n=38) and the normal renal function group [eGFR≥90 ml/(min·1.73 m2)] (n=38) according to their eGFR. All subjects underwent brain MRI, cognitive and psychiatric testing. The SVD scores were measured, total white matter hyperintensity (WMH) and SVD scores were calculated, and the risk factors of SVD scores were analyzed by using ordinal logistic regression.@*Results@#SLE patients in the impaired renal function group showed higher basal ganglia PVS, centrum semiovale perivascular space (PVS), periventricular WMH, deep WMH and total SVD scores compared with normal controls or patients with normal renal function (H=44.568, 31.380, 31.172, 43.419, 24.317, P<0.001) . The ordinal logistic regression analysis showed that C-reactive protein was a risk factor for SVD in patients with SLE(OR=1.323, P<0.01).@*Conclusion@#SLE patients with impaired renal function had a higher SVD burden on MR imaging, particularly PVS in the basal ganglia and deep WMH, which was affected by the C-reactive protein level.
Résumé
4D Flow MRI is a new phase contrast MR technique,which can spatially encode velocity in three-direction,collect multi-directional blood flow data,and result in complex three-dimensional dynamic parameters.4D Flow MRI is more accurate and comprehensive than 2D phase contrast MRI and Doppler echocardiography.However,4D Flow MRI have some disadvantages,such as long scanning time,noise,etc.,which are the future key technical issues to be addressed.4D Flow MRI technology has a great potential in clinical applications,such as intracranial vascular diseases,cardiac magnetic resonance imaging,and other aspects of aortic diseases.Research advances in clinical application of 4D Flow MRI were reviewed in this paper.
Résumé
Objective To construct a mutant strain of Streptococcus mutans ( S.mutans ) with clpC-deletion and to investigate the role of clpC gene in genetic competence.Methods The fragment of clpC gene and the kanamycin resistant cassette flanked by two loxP sites were amplified by PCR.The purified fragment of clpC gene was cloned into pMD-19T simple vector to construct pCKX1.The pCKX1 vector was digested with ClaⅠ/EcoRⅠ, then blunted and introduced into lox71-KMR-lox66 to obtain pCKX2 vector via homologous recombination.The pCKX2 vector was linearized with SalⅠ and transformed into S.mutans UA159 strain.The positive strains constructed via homologous recombination were screened with kanamycin and transformed with the thermosensitive plasmid pCrePA.The KMR cassette was excised after incubating at 30℃ for 48 hours.Then the pCrePA plasmid was removed after overnight incubating at 37℃for the prepara-tion of clpC-deletion mutant.Total RNA were extracted from the S.mutans UA159 strain and the clpC-dele-tion mutant strain respectively, and then reverse transcribed into first strand cDNA.The target gene frag-ments were amplified by RT-PCR and analyzed by the agarose gel electrophoresis and sequencing.After be-ing verified by PCR and sequencing, the S.mutans UA159 strain and the clpC-deletion mutant strain were re-spectively transformed with E.coli-S.mutans shuttle vector pDL276 to observe the competence development induced by the competence-stimulating peptide (CSP).Results The PCR and sequencing results showed that the pCKX2 vector and the mutant strain with clpC-deletion were constructed successfully via homologous recombination.No clpC gene was detected in the clpC-deletion mutant as indicated by RT-PCR analysis.The formation of competent clpC-deletion mutant was delayed and the competence state was prolonged as com-pared with its parent strains.Conclusion The clpC gene negatively regulated the formation of competent S.mutans.