Objective:To explore MRI T 2-mapping and blood oxygenation level dependent (BOLD) to evaluate the functional changes of paraspinal muscle in rats with discogenic low back pain (DLBP) after swimming. Methods:Totally 54 female 1-month-old SD rats were selected, which were divided into 3 groups by random number table method, sham operation (Sham) group, DLBP non-swimming group and DLBP swimming group, with 18 rats in each group. Under the guidance of X-ray fluoroscopy, the L4/5 and L5/6 intervertebral discs of the rats in the DLBP non-swimming group and DLBP swimming group were punctured by the posterior approach, and establishment of DLBP rat model by destroying nucleus pulposus, and only paraspinal muscles at the same level were punctured in the Sham group. After modeling, the DLBP swimming group received swimming exercise intervention for 5 consecutive days (30 min/d), while the DLBP non-swimming group and Sham group did not receive any rehabilitation exercise intervention. Each group was divided into 3 time point subgroups on average, the T 2-mapping and BOLD sequences were scanned at 30, 90 and 180 days after modeling to obtain the T 2 value, R 2* value of the paraspinal muscles, and the paraspinal muscles at the modeling level were taken for immunofluorescence staining, and the fluorescence intensity of myosin heavy chain (MYH)1 (type Ⅱ muscle fiber) and MYH7 (type I muscle fiber) was analyzed. One-way analysis of variance was used for comparison among the 3 groups, and the Bonferroni method was used for multiple comparisons, and Pearson correlation coefficient was used to evaluate the correlation between quantitative MRI parameters T 2 value, R 2* value and MYH1, MYH7 immunofluorescence intensity of rat paraspinal muscles at 180 days after modeling. Results:At 30 days after modeling, there was no significant difference in T 2 value and R 2* value among the 3 groups (all P>0.05). At 90 days after modeling, the T 2 value of the DLBP swimming group was higher than that of the DLBP non-swimming group, and the T 2 value of the DLBP non-swimming group was lower than that of the Sham group (all P<0.05), and there was no significant difference in the R 2* value among the 3 groups ( P>0.05). At 180 days after modeling, the T 2 value of the DLBP swimming group was higher than that of the DLBP non-swimming group, and the R 2* value was lower than that of the DLBP non-swimming group; the T 2 value of the DLBP non-swimming group was lower than that of the Sham group, and the R 2* value was higher than that of the Sham group (all P<0.05). At 30 and 90 days after modeling, there was no significant difference in the expressions of MYH1 and MYH7 among the 3 groups (all P>0.05). At 180 days after modeling, the expression of MYH1 decreased and the expression of MYH7 increased in the DLBP swimming group compared with the DLBP non-swimming group; the expression of MYH1 increased and the expression of MYH7 decreased in the DLBP non-swimming group compared with the Sham group (all P<0.05). At 180 days after modeling, the T 2 value had a moderate negative correlation with the fluorescence intensity of MYH1 ( r=-0.511, P=0.043), and a moderate positive correlation with the fluorescence intensity of MYH7 ( r=0.564, P=0.023); R 2* value was moderate positive correlated with the fluorescence intensity of MYH1 ( r=0.625, P=0.010), and moderate negative correlated with the fluorescence intensity of MYH7 ( r=-0.653, P=0.006). Conclusions:Swimming exercise can improve the reduction of water content and perfusion in the paraspinal muscles of DLBP rats, and reduce the transformation of muscle fibers from type Ⅰ to type Ⅱ, the changes of T 2 and R 2* value can reflect the transformation of paraspinal muscle fiber types to a certain extent.

Objective To preliminarily evaluate the application value of SpyGlass direct visualization system in the diagnosis and treatment of biliary stricture after liver transplantation. Methods Clinical data of 4 patients presenting with biliary stricture after liver transplantation who underwent SpyGlass direct visualization system examination were collected. The examination, treatment and prognosis of biliary stricture were analyzed. Results The examination results of color Doppler ultrasound, magnetic resonance cholangiopancreatography (MRCP) and endoscopic retrograde cholangiopancreatography (ERCP) in 4 patients suggested biliary anastomotic stricture with intrahepatic biliary dilatation, and 2 of them were complicated with intrahepatic biliary calculi. Repeated placement of biliary stent under ERCP yielded poor effect in 3 cases. SpyGlass direct visualization system examination hinted biliary anastomotic stricture in 4 patients, 3 cases of intrahepatic biliary dilatation, 3 cases of intrahepatic biliary calculi, 2 cases of purulent bile and 3 cases of floccules within the biliary tract, 1 case of congestion and edema of biliary tract wall and 2 cases of local epithelial necrosis and stiffness changes of intrahepatic biliary tract wall. The wire could not be inserted in 1 patient due to severe biliary anastomotic stricture. Four patients were treated with biliary stricture resection + biliary stone removal + biliary end-to-end anastomosis, biliary stricture resection + biliary-intestinal anastomosis, ERCP lithotomy + biliary metal stent implantation, and biliary metal stent implantation + percutaneous transhepatic bile duct lithotomy, respectively. Relevant symptoms were relieved without evident complications. All patients survived during the follow-up until the submission date. Conclusions Compared with traditional imaging examination, SpyGlass direct visualization system may more directly display the morphological characteristics of biliary tract wall and structural changes within biliary tract cavity, which is an effective examination tool for biliary stricture after liver transplantation. In addition, individualized treatment methods may be adopted for different biliary tract diseases, which is expected to improve clinical prognosis of patients.

Diseases of ocular fundus are the leading causes of severe vision impairment or even blindness in patients worldwide, and the medical treatments are seriously limited by the difficulty of therapeutic drugs entering the fundus due to the various physiological barriers. Nano-drug delivery systems, with their nanoscale size and large surface area, can be loaded with therapeutic drugs of different physicochemical properties and modified with various surface active substances, which can not only improve the solubility and penetration of the drugs, but also protect biologic drugs from degradation and improve the biological safety and bioavailability, as well as deliver therapeutic drugs to specific ocular targets. All of these make the therapeutic potential enormous. Currently, more and more studies have been carried out to take advantage of nanomaterials for the treatment of different fundus diseases, including neurodegenerative diseases, fundus neovascularization, endophthalmitis and fundus tumors. This review analyzes the challenges and barriers faced by different routes of drug administration in the treatment of fundus diseases, the physicochemical properties of common nano-drug delivery systems that have been studied in related fields, and further summarizes the progress, advantages, limitations, and future directions of the application of various nano-drug delivery systems for the treatment of ocular fundus diseases in recent years.

MA Yueh-ch'ing (1906—1984), graduated from Peking Union Medical College in 1934, and became the first Chinese anesthetist hired by Peking Union Medical College Hospital in 1939. Based on the development and historical background of global anesthesiology, this article briefly introduces MA Yueh-ch'ing's personal experience and major achievements in anesthesiology.