Preparation of 89Zr-labeled mesenchymal stem cells and PET monitoring in mice with systemic lupus erythematosus / 中华核医学与分子影像杂志

Objective:To label mesenchymal stem cells (MSCs) with 89Zr-oxine complex, and assess its characteristics of PET imaging in systemic lupus erythematosus (SLE) model (MRL/lpr mice). Methods:SLE mice were screened by 18F-FDG PET imaging. 89Zr-oxine was prepared and used for labeling MSCs (10 6 MSCs and 1 MBq 89Zr-oxine). 89Zr-oxine-labeled MSCs (0.2 MBq) were injected into MRL/lpr mice and BALB/c mice (each n=5) via tail vein at a dose of 1.2×10 6 cells per mouse, and followed with microPET imaging in vivo at 2 h, 6 h, 1 d, 3 d, 7 d, 10 d and 14 d after injection. The percentage activity of injection dose per gram of tissue (%ID/g) was calculated. Independent-sample t test was used to analyze the data. Results:MSCs was successfully labeled with 89Zr-oxine, with the labeling efficiency of 20% and cell viability >90%. MicroPET imaging showed that MSCs were mainly distributed in lungs and the liver sites at 2 h after injection. The number of MSCs homing to kidneys of MRL/lpr mice ( n=5) increased significantly 24 h after the injection, and the renal uptake of MSCs in MRL/lpr mice was much higher than that in BALB/c mice ((8.28±1.27) vs (4.33±0.94) %ID/g; t=3.54, P=0.024). The renal uptake increased firstly and then decreased and then leveled off, indicating MSCs homing to kidneys. Conclusions:A method for 89Zr-oxine labeling of MSCs is successfully established. 89Zr-labeled MSCs can home to kidneys of SLE mice. PET imaging of 89Zr-labeled MSCs can be effectively used to explore the in vivo distribution and migration behavior of transplanted MSCs during the treatment of diseases such as SLE.

Multicenter study on the etiology characteristics of neonatal purulent meningitis / 中华传染病杂志

Objective:To study the distribution and antibiotics resistance of the main pathogens of neonatal purulent meningitis in different regions of China.Methods:A retrospective descriptive clinical epidemiological study was conducted in children with neonatal purulent meningitis which admitted to 18 tertiary hospitals in different regions of China between January 2015 to December 2019. The test results of blood and cerebrospinal fluid, and drug sensitivity test results of the main pathogens were collected. The distributions of pathogenic bacteria in children with neonatal purulent meningitis in preterm and term infants, early and late onset infants, in Zhejiang Province and other regions outside Zhejiang Province, and in Wenzhou region and other regions of Zhejiang Province were analyzed. The chi-square test was used for statistical analysis.Results:A total of 210 neonatal purulent meningitis cases were collected. The common pathogens were Escherichia coli ( E. coli)(41.4%(87/210)) and Streptococcus agalactiae ( S. agalactiae)(27.1%(57/210)). The proportion of Gram-negative bacteria in preterm infants (77.6%(45/58)) with neonatal purulent meningitis was higher than that in term infants (47.4%(72/152)), and the difference was statistically significant ( χ2=15.54, P=0.001). There were no significant differences in the constituent ratios of E. coli (36.5%(31/85) vs 44.8%(56/125)) and S. agalactiae (24.7%(21/85) vs 28.8%(36/125)) between early onset and late onset cases (both P>0.05). The most common pathogen was E. coli in different regions, with 46.7%(64/137) in Zhejiang Province and 31.5%(23/73) in other regions outside Zhejiang Province. In Zhejiang Province, S. agalactiae was detected in 49 out of 137 cases (35.8%), which was significantly higher than other regions outside Zhejiang Province (11.0%(8/73)). The proportions of Klebsiella pneumoniae, and coagulase-negative Staphylococcus in other regions outside Zhejiang Province (17.8%(13/73) and 16.4%(12/73)) were both higher than those in Zhejiang Province (2.9%(4/137) and 5.1%(7/137)). The differences were all statistically significant ( χ2=14.82, 12.26 and 7.43, respectively, all P<0.05). The proportion of Gram-positive bacteria in Wenzhou City (60.8%(31/51)) was higher than that in other regions in Zhejiang Province (38.4%(33/86)), and the difference was statistically significant ( χ2=6.46, P=0.011). E. coli was sensitive to meropenem (0/45), and 74.4%(32/43) of them were resistant to ampicillin. E. coli had different degrees of resistance to other common cephalosporins, among which, cefotaxime had the highest resistance rate of 41.8%(23/55), followed by ceftriaxone (32.4%(23/71)). S. agalactiae was sensitive to penicillin, vancomycin and linezolid. Conclusions:The composition ratios of pathogenic bacteria of neonatal purulent meningitis are different in different regions of China. The most common pathogen is E. coli, which is sensitive to meropenem, while it has different degrees of resistance to other common cephalosporins, especially to cefotaxime.

Development and construction of comprehensive examination database for periodontology based on curriculum integration / 中华医学教育探索杂志

Periodontology is one of the important disciplines in oral clinical medicine, which covers a wide range of subjects and intersects with many basic disciplines. Under the environment of the implementation of modular teaching in Shanghai Jiao Tong University School of Medicine, the assessment method with separate propositions for the teaching and research section is still adopted. There is a mismatch between the assessment mode and the curriculum setting; the basic subject propositions are difficult to be combined with clinical cases; the knowledge point assessment is single, and the students' ability to integrate the knowledge points cannot be assessed. The development and construction of the comprehensive examination database for periodontology was based on curriculum integration, gathering the teaching backbones of various disciplines, focusing on periodontology, radiating all related disciplines, unifying the proposition outline, proposition type, proposition principle, combining with relevant knowledge points of various disciplines based on clinical cases, and tried to apply to clinical students majoring in stomatology. The use of the examination database promotes students' ability to flexibly apply theoretical knowledge to clinical case analysis, further promotes the reform of modular teaching, lays a solid foundation for future clinical work, and meanwhile provides an important basis for directions of the teaching and research section.

The Mechanism of Brain Injury Induced by Rotational Motion / 医用生物力学

Traumatic brain injury ( TBI ) has caused serious economic and social burdens, but due to its heterogeneity, there is no effective treatment. In TBI with different severity, diffuse axonal injury (DAI) incidenceis high. The investigation on DAI will contribute to the diagnosis and treatment of TBI. In this study, the classification of TBI and the research status of DAI were summarized. The method to judge the severity of TBI and DAI, and animal experimental models and related injury criteria and thresholds were reviewed. The result show that DAI is mainly generated by rotational acceleration and it is related to angular acceleration, angular velocity and duration. Several TBI animal models can induce the pathology of DAI, and inertial rotation models which can produce only rotational acceleration have been developed. However, these models are instantaneous rotation models, and the rotation duration is uncontrollable, thus a longer duration is impossible, and DAI severity under long rotational motion cannot be studied. The study proposes that a new rotation animal model which can control rotation duration should be developed. The development of the animal model and investigation on pathomechanism of the model will contribute to the prevention and treatment of DAI.

Fracture Classification and Injury Segment Analysis of Tibiofibula and Ankle in Half-Squat Parachuting Landing / 医用生物力学

Objective To make classification and segment measurement for the cases with tibiofibular and ankle fractures in parachuting landing, and investigate main classification types of parachuting fractures and fracture segments of high risk.Methods A total of 56 fracture cases in parachuting landing were collected, and the tibiofibula and ankle fractures were classified according to AO-OTA or Lauge-Hansen classification standards respectively based on their digital X-ray images. The medium plane between talus and tibia joint planes in ankle joint was defined as the reference plane. The highest and lowest injury points of tibia and fibula were marked respectively, and the fracture segment was defined between the highest and lowest point for statistical analysis.Results For tibiofibular and ankle fracture cases in parachuting landing, fracture at both tibia and fibula accounted for 80.4%. The major classification of tibiofibula fracture was 42-D/5.2 (45.8%) and 42-D/5.1 (16.7%). The major classification for ankle fracture was pronation-external rotation (PER, 59.4%) and supination-external rotation (SER, 37.5%). When tibiofibular and ankle fracture cases in parachuting landing occurred, the fracture segment of the tibia was mainly from 57 to 143 mm above the reference plane and from 6 mm below the reference plane to 24 mm above the reference plane, while the fracture segment of the fibula was 4-45 mm and 74-83 mm above the reference plane. Injury risks of all above segments were higher than 50%.Conclusions For protection of lower limbs in parachuting landing, the fracture at both tibia and fibula should be highly noticed. The ankle motion of PER and SER should be especially restricted in parachuting ankle protection.

Spatial Distribution of Biomechanical Characteristics for Trabecular Bone in the Femoral Head with Osteonecrosis / 医用生物力学

Objective To explore the spatial distribution of microstructural parameters and mechanical properties for trabecular bone in the femoral head with osteonecrosis. Methods Microstructural parameters and mechanical properties of trabecular bone in different regions were analyzed by combined use of imaging measurements and numerical simulation method, and the spatial distribution of biomechanical properties for trabecular bone along coronal, sagittal and vertical directions was investigated. Results Microstructural characteristics and mechanical properties of trabecular bone were Y-shaped distributed along coronal and sagittal directions, and mechanical properties of trabecular bone in Y-shaped region were higher than those in the other regions. Such distribution characteristics was consistent with the location of principle compressive group in the femoral head. Conclusions Necrotic lesions in Y-shaped region had a greater influence on stress distribution of the femoral head and might cause the deterioration of osteonecrosis. The spacial correlation between necrotic lesions and Y-shaped region should be fully considered during clinical diagnosis.

Application value of low-dose 4DCT scanning in simulation and target delineation for solitary pulmonary tumors / 中华放射肿瘤学杂志

Objective:To explore the feasibility of low-dose 4DCT scanning in simulation and target delineation for solitary pulmonary tumors (SPTs).Methods:23 patients with SPTs received 4DCT scanning simulation with the conventional scanning (CON), low voltage (LV), low current (LA) and low voltage combined with low current (LVA) in sequence. Based on the 4DCT images derived from the four sets of scanning parameters, the internal gross tumor volume (IGTV CON, IGTV V, IGTV A, IGTV VA) of SPTs were delineated and matched. Taking IGTV CON as reference, the tumor displacement and the centroid position of IGTV V, IGTV A and IGTV VA were compared with IGTV CON. The radiation doses under different scanning parameters were compared. Results:The volumes of IGTV CON, IGTV V and IGTV A were (12.26±12.30) cm 3, (12.21±12.16) cm 3 and (11.87±11.70) cm 3, respectively ( P=0.337). IGTV VA was (11.34±11.07) cm 3, significantly smaller than IGTV CON ( P=0.005). There was no significant difference in the centroid positions of IGTV CON, IGTV V, IGTV A and IGTV VA in three directions ( P=0.491, 0.360, 0.136). The Dice′s similarity coefficient (DSC VA) was significantly lower than DSC V and DSC A ( P=0.004, 0.030). The tumor displacement measured by the four sets of 4DCT images was similar in the LR direction ( P=0.470), and also in the AP direction ( P=0.108). For the displacement in the SI direction, LVA scanning was smaller than CON ( P=0.015). The radiation doses under four different scanning conditions were (397.0±140.3) mGy·cm, (175.0±61.8) mGy·cm, (264.8±95.3) mGy·cm and (116.8±41.2) mGy·cm, respectively ( P<0.001). Conclusions:LV or LA scanning exert no significant effect on the volume, centroid position of IGTV and the tumor displacement in 4DCT simulation for SPTs. The radiation dose that patients receive under LV and LV scanning is lower than that of CON. Consequently, LV or LA scanning is feasible in 4DCT simulation and target delineation for SPTs.

Changes and influencing factors of splanchnic regional oxygenation before and after feeding in preterm infants with feeding intolerance / 中国新生儿科杂志

Objective:To study the changes and influencing factors of splanchnic regional saturation before and after feeding in preterm infants with feeding intolerance (FI).Methods:From December 2018 to August 2019, preterm infants with FI admitted to the neonatal intensive care unit of our hospital within 24 hours after birth were prospectively enrolled in this same-patient before-after study. Splanchnic regional saturation (rSsO 2) and cerebral regional oxygenation (rSc0 2) 5 minutes before feeding and 1 hour after feeding were monitored using near-infrared spectroscopy (NIRS). The average values of rScO 2, rSsO 2 and splanchnic-cerebral oxygenation ratio (SCOR) before and after feeding were calculated. The clinical data including postnatal age, corrected gestational age and feeding methods (breastfeeding or formula feeding) were collected. Single-factor correlation analysis and multiple linear regression were used to analyze the influencing factors of rSsO 2 before and after feeding. Results:A total of 41 preterm infants were included. No significant differences existed in rSsO 2, rScO 2 and SCOR before and after feeding ( P>0.05). The feeding methods showed relative prominent influences on the changes of rSsO 2 and SCOR before and after feeding. The breastfeeding infants had smaller changes of rSsO 2 and SCOR before and after feeding compared with formula feeding infants, the regression equations were Y=5.538-4.065X (model complex correlation coefficient was 0.414 determination coefficient R2=0.171, F=8.050, P<0.01) and Y=0.109-0.075X (model complex correlation coefficient was 0.405 determination coefficient R=0.1642, F=7.655, P<0.01). Conclusions:Proper feeding will not increase rSsO 2 in preterm infants with FI. Comparing with formula feeding infants, breastfeeding infants has more stable post-feeding rSsO 2.Breastfeeding should be the first choice for preterm infants with FI.

Evaluation of Optimal Gravity Center Position of Backpack in Half-Squat Parachuting Landing / 医用生物力学

Objective To study effects of backpack gravity center position on kinetics and kinematics of lower-extremity joints in parachuting landing and evaluate the injuries. Methods Seven participants performed parachuting landing with backpack gravity center on three positions: low-back (position 1), upper-back (position 2) and abdomen (position 3). Results The peak vertical ground reaction force (GRF) with backpack on position 2 was significantly lower than that on position 1. The joint moment on sagittal plane of the hip with backpack on position 2 was significantly higher than that on position 1 and position 3. The joint energy absorption of the hip with backpack on position 2 was significantly higher than that on position 1. The angular displacement of the hip on sagittal plane with backpack on position 2 was significantly higher than that on position 1 and was significantly lower than that on position 3. The angular velocity of the hip on sagittal plane with backpack on position 2 was significantly lower than that on position 3. Conclusions Different positions of backpack gravity center could significantly influence kinetic and kinematic parameters of the hip. Backpack gravity center on upper-back position could decrease the lower-extremity injuries. The results can provide evidences for evaluating backpack gravity center and decreasing injuries in parachuting landing.

Study of sub-region segmentation of brain metastases based on magnetic resonance perfusion imaging / 中华放射肿瘤学杂志

Objective:To evaluate the feasibility of magnetic resonance (MR) perfusion imaging for sub-region segmentation of brain metastases (BMs), and to provide reference for individualized radiotherapy based on blood flow perfusion heterogeneity in BMs patients.Methods:96 BMs patients were selected, including 55 patients with necrosis and 41 without necrosis. Each patient was scanned with CT simulation and MR simulation before radiotherapy. MIM Maestro 6.8.8 software was used to delineate the gross tumor volume (GTV) and necrosis GTV (GTV N) from enhanced T 1W images and T 2 Propeller images, respectively, and the solid GTV (GTV S) was obtained by the subtraction of the two. Then, the cerebral blood flow map of three dimensional arterial spin labeling (3D-ASL) was employed to determine the high perfused GTV (GTV H) and low perfused GTV (GTV L). The volume and proportion of sub-regions were counted and compared between two groups and the correlation of each sub-region was analyzed. Results:The volume of GTV in the necrosis and non-necrosis groups was 19.56 and 7.34 cm 3, respectively. Besides, the AUC of the ROC between GTV volume and necrosis was 0.749. In the necrosis group, the ratio of GTV N, GTV S, GTV H and GTV L to GTV was 20.47%, 79.53%, 33.03% and 46.50%, respectively (all P<0.05). Among them, the r value between GTV S and GTV was 0.963, 0.849 for GTV L and GTV, and 0.840 for GTV L and GTV S, significantly higher than 0.683 for GTV H and GTV and 0.764 for GTV H and GTV S (all P<0.05). In the non-necrosis group, the ratio of GTV H to GTV was higher than that in the necrosis group (58.95% vs. 33.03%, P<0.05). In addition, the ratio of GTV L to GTV was slightly lower than that in the necrosis group (41.05% vs. 46.50%, P>0.05). The r value between GTV H and GTV was 0.776, significantly higher than 0.574 between GTV L and GTV ( P<0.05). Conclusion:MR-3D-ASL can quantitatively analyze the heterogeneous blood perfusion of BMs, which could guide the sub-region segmentation and local dose escalation of tumors.

Mechanical Properties of Calcification from Human Aortic Valve / 医用生物力学

Objective To measure mechanical properties of calcified tissues from human aortic valve by nanoindentation test. Methods Leaflets from 5 patients with aortic stenosis were collected. Elastic modulus and hardness of the calcified leaflets were obtained by nanoindentationtest. Results The elastic modulus and hardness of the calcified leaflets were (15.69±3.89) GPa and (0.59±0.15) GPa, respectively. Conclusions The elastic modulus and hardness of the calcified valve tissues can be obtained by nanoindentationtest, which provides experimental data for biomechanical research of the valve.

Evaluation of the feasibility of Gd-based contrast clearance difference to delineate subvolume target in radiotherapy for primary and metastatic brain tumors / 中华放射肿瘤学杂志

Objective:To evaluate the feasibility of delineating subvolume target in radiotherapy for brain tumors using Gd-based contrast clearance difference.Methods:Twenty-six patients with malignant brain tumors were scanned with MRI. The first and second acquisitions of standard T 2-weighted images (T 2WI) and T 1-weighted images (T 1WI) were performed at 5 min and 60 min after injection of contrast agent. Delayed contrast extravasation (DCEM) MRI computed by Brainlab comprised regions of contrast agent clearance representing active tumors and regions of contrast accumulation representing non-tumor tissues. Based on T 2WI images, 14 patients with liquefaction necrosis were divided into group A, and 12 patients without liquefaction necrosis into group B, respectively. Then, gross target volume (GTV) was delineated on T 1WI images. Based on the GTV, active tumor (GTV tumor) and non-tumor regions (GTV non-tumor) were delineated on T 1WI-DCEM fusion images, while liquefaction necrosis (GTV liquefaction) and non-liquefaction (GTV non-liquefaction) were delineated on T 1-T 2WI fusion images. Finally, the differences between different subvolumes were compared by paired t-test. Results:In group A, the GTV non-liquefaction and GTV liquefaction were (13.65±18.15) cm 3 and (6.30±7.57) cm 3. The GTV tumor was (10.40±13.52) cm 3 and the GTV non-tumor was (9.55±14.57) cm 3. The GTV non-liquefaction was significantly increased by 16.3% on average compared with the GTV tumor ( P<0.05). The GTV non-tumor was significantly increased by 16.3% on average compared with the GTV liquefaction ( P<0.05). In group B, The GTV non-tumor was significantly reduced by 68.8% on average compared with the GTV tumor ( P<0.05). Conclusions:Compared with T 2WI, DCEM has advantages in identifying the liquefaction area and can clearly differentiate the subvolume of active tumors from non-liquefaction necrosis. DCEM provides evidence for guiding the delineation of subvolume in primary and metastatic brain tumors.

Effectiveness and safety of tirofiban combined with intravenous thrombolysis in the treatment of elderly patients with acute ischemic stroke / 国际脑血管病杂志

Objective:To investigate the effectiveness and safety of early combined with tirofiban in the treatment of elderly patients with acute ischemic stroke after intravenous thrombolysis with alteplase.Methods:Elderly (60-75 years old) patients with acute ischemic stroke received intravenous alteplase thrombolysis in the Department of Neurology, Traditional Chinese Medicine Hospital of Huangdao District, Qingdao from January 2018 to May 2020 were enrolled prospectively. According to whether tirofiban is combined or not, they were divided into tirofiban group and non-tirofiban group. Tirofiban was pumped intravenously 2 h after intravenous thrombolysis, first 0.4 μg/(kg·min) for 30 min, then 0.1 μg/(kg·min) for 24 h. The efficacy endpoints included National Institutes of Health Stroke Scale (NIHSS) score at 7 d after treatment and modified Rankin Scale (mRS) score at 90 d after onset. 0-2 was defined as good outcome, and >2 was defined as poor outcome. The safety endpoints included the incidence of hemorrhagic transformation, symptomatic intracranial hemorrhage (sICH) and mortality within 90 days after onset.Results:A total of 124 patients with acute ischemic stroke were enrolled. The median age was 68 years (range, 60-75 years). There were 73 males (58.9%) and 51 females (41.1%). There were 62 patients (50%) in the tirofiban group and 62 (50%) in the non-tirofiban group. The median baseline NIHSS score was 14. Hemorrhagic transformation occurred in 7 patients (5.6%), of which 2 were sICH (1.6%). The follow-up at 90 d after onset showed that 68 patients (54.8%) had a good outcome, 56 (45.2%) had a poor outcome, of which 4 (3.2%) died. The NIHSS score at 7 d after treatment (5.52±4.79 vs. 7.35±3.80; t=2.357, P=0.020) and the rate of good outcome at 90 d after onset (64.5% vs. 45.2%; χ2=4.689, P=0.030) in the tirofiban group were significantly better than those of the non-tirofiban group, and there were no significant differences among the incidence of hemorrhagic transformation (4.8% vs. 6.5%; P=1.000), sICH (1.6% vs. 1.6%; P=1.000), and 90 d mortality (3.2% vs. 3.2%; P=1.000). Conclusion:After intravenous thrombolysis with alteplase, the early combined treatment with tirofiban in elderly patients with acute ischemic stroke can significantly improve the efficacy and outcome, and will not increase the risk of hemorrhagic transformation, sICH and death.

Risk factors for ischemic stroke in patients with spontaneous extracranial vertebral artery dissection / 国际脑血管病杂志

Objective:To investigate the risk factors for ischemic stroke in patients with spontaneous extracranial vertebral artery dissection.Methods:From November 2013 to December 2019, patients with spontaneous extracranial vertebral artery dissection admitted to the Department of Neurology, Baotou Central Hospital were enrolled retrospectively. According to whether they had ischemic stroke or not, they were divided into ischemic stroke group and non-ischemic stroke group. The independent risk factors for ischemic stroke in patients with spontaneous extracranial vertebral artery dissection were identified by binary logistic regression analysis. Results:A total of 39 patients were enrolled, 25 were female (64.1%), 14 were males (35.9%), their age was 51.51±14.98 years old, 16 of them (41.0%) had ischemic stroke. The proportion of patients with double-lumen sign, intimal flap sign of occluded lumen (37% vs. 4%; P=0.013) and specific initial symptoms (56% vs. 9%; P=0.003) of the ischemic stroke group were significantly higher than those of the non-ischemic stroke group. Multivariate logistic regression analysis showed that double-lumen sign and intimal flap sign of occluded lumen (odds ratio 47.951, 95% confidence interval 26.284-87.478; P<0.001), and specific initial symptoms (odds ratio 19.232, 95% confidence interval 10.695-34.587; P<0.001) were independently associated with ischemic stroke in patients with spontaneous extracranial vertebral artery dissection. Conclusions:Double-lumen sign, intimal flap sign of occluded lumen and specific clinical symptoms are the independent risk factors for ischemic stroke in patients with spontaneous extracranial vertebral artery dissection.

MicroPET and biodistribution of 68Ga-labeled human epidermal growth factor receptor 2 binding affibody imaging probe / 中华核医学与分子影像杂志

Objective:To prepare a 68Ga labeled human epidermal growth factor receptor 2 (HER2) affibody 68Ga-1, 4, 7-triazacylononane-1, 4, 7-triacetic acid (NOTA)-maleimide (MAL)-Cysteine (Cys)-Glycine-Glycine-Glycine-Arginine-Aspartic acid-asparagine-HER 2: 342 affibody (GGGRDN-ZHER 2: 342)( 68Ga-MZHER), and evaluate its biodistribution and microPET characteristics. Methods:NOTA-MAL-Cys-GGGRDN-ZHER 2: 342 conjugate was labeled with 68Ga in one step. Radiochemical purity, radiolabeling yield and stability in vitro were analyzed. Normal mice ( n=24) were scarified at 15, 30, 60 and 120 min postinjection (1.85 MBq 68Ga-MZHER) to measure radioactive counts (percentage activity of injection dose per gram of tissue (%ID/g)) in main organs. Biodistribution and kinetics were evaluated by dynamic microPET in mice. Ovarian cancer (SKOV-3) models were established and microPET was performed at 30, 60 and 120 min postinjection of radiotracer. After administration of unlabeled Cys-ZHER 2: 342 peptide (10 mg/kg body weight) for 30 min, 68Ga-MZHER was injected into mice and PET images were acquired at 60 min postinjection. Region of interest (ROI) was drawn to access time-activity curve (TAC) in main organs and tumor. Six normal mice were used for the safety study. Results:68Ga-MZHER was synthesized in about 15 min with the yields more than 90%, and radiochemical purity more than 95%. The radiochemical purity was also determined to be more than 95% after being stored for 120 min at room temperature. Predominant uptake of 68Ga-MZHER was in the kidneys, and was cleared rapidly in normal tissues except the kidney. At 15 min postinjection, the renal uptake value was (106.36±15.74) %ID/g, then gradually increased with time, up to (145.15±28.04) %ID/g (60 min), and decreased to (86.12±22.75) %ID/g after 120 min postinjection. The blood pharmacokinetic of the probe in mice was fit with the two-compartment model. MicroPET imaging in mice bearing HER2 positive SKOV-3 tumors showed that the xenografts were clearly visualized with good contrast to normal tissue. The uptakes in tumors was determined to be (11.26±0.50), (12.27±1.13) and (12.65±0.89) %ID/g at 30, 60 and 120 min postinjection. Block experiment showed that the corresponding values decreased to (1.25±0.28) %ID/g at 60 min postinjection. Safety studies showed that after injection of 68Ga-MZHER for 30 d, the mice survived and no obvious abnormalities were observed in the main organs as shown in pathological results. Conclusions:68Ga-MZHER can be successfully labeled by one-step method. The 68Ga-MZHER probe owns the advantages of favorable imaging properties, convenient preparation, excellent stability, safety, rapid clearance in the blood, which support its application for further research.

Evaluation of bovine pericardium performance after liquid nitrogen freezing and thinning / 生物医学工程学杂志

In the present study, the performance of the liquid nitrogen frozen and thinned bovine pericardium was studied and compared with the porcine pericardium. The microstructure and mechanical properties of the bovine pericardium were observed and tested by hematoxylin-eosin (HE) staining and tensile test respectively. In all conditions, porcine pericardium was selected as a control group. The results showed that there was little difference in the performance of bovine pericardium after being frozen by liquid nitrogen. The secant modulus and ultimate strength of the thinned bovine pericardium were similar to those of porcine pericardium, however, the elastic modulus was a little higher than porcine pericardium. The study suggested that the performance of the thinned bovine pericardium was similar to those of porcine pericardium. It was easy for the thinned bovine pericardium to obtain a relatively ideal thickness and expected performance, therefore, the thinned bovine pericardium can be used as the materials of transcatheter aortic valve leaflets.

Efficacy of multi-sensory stimulation on psychological, behavioral symptoms and health-related quality of life in patients with Alzheimer's disease / 中华行为医学与脑科学杂志

Objective To investigate the effects of multisensory stimulation on mental behavioral symptoms and health-related quality of life in patients with Alzheimer's disease (AD).Methods From March 2018 to August 2018,159 AD patients (65-75 years old) in neurology and psychiatric clinic of the Second Affiliated Hospital of Fujian Medical University were enrolled.Randomized grouping was performed by randomized software,experimental group (multi-sensory stimulation),81 cases,control group (no intervention),78 cases.The experimental group had a multi-sensory stimulation for 16 weeks,twice a week,40 minutes each time,for a total of 32 times.At the time of enrollment and 16 weeks after the intervention,the simple neuropsychiatry scale (NPI-Q) and the health-related quality of life questionnaire (HRQLS) were filled out.The t-test and two-factor repeated measures analysis of variance were used to analyze the data.Results The NPI-Q scores of the two groups before and after intervention were compared by two-factor repeated measurement ANOVA.There was no significant difference in NPI-Q average score between the expermental group(2.20±0.22) and control group(2.17±0.35) before intervention (t=0.53,P=0.595).After intervention NPI-Q average score of the experimental group(2.17±0.46) was lower than that of the control group (1.71±0.29) (t =7.56,P＜ 0.01).The intervention effect (F=50.77,P＜ 0.0 1),the time effect (F=39.20,P＜0.01) and interaction effect (F=33.89,P＜0.01) were statistically significant.The HRQLS scores of the two groups before and after intervention were compared by two-factor repeated measurement ANOVA.The intervention effect(F=140.82,P＜0.01),the time effect (F=56.64,P＜0.01) and interaction effect (F=60.38,P＜0.01) were statistically significant.Conclusion Multisensory stimulation can improve mental behavioral symptoms in patients with Alzheimer's disease and improve health-related quality of life.

Analysis on High Purity Magnesium Bone Screws in vivo / 医用生物力学

Objective To compare the in vivo degradation rates of two different kinds of high purity magnesium bone screws by animal experiments, so as to make some suggestions on structural design of high purity magnesium bone screws. Methods High purity magnesium bone screws with threads and without threads were implanted into femoral condyles of New Zealand rabbits separately. Twenty-four rabbits were randomly divided into 3 groups. They were euthanized at 8, 12 and 16 weeks after operation, respectively. The in vivo degradation rates of bone screws with two different shapes were compared through micro-CT scanning and Skyscan CT-analyser software, and the stress changes during the progress of bone screw degradation were analyzed. Results The initial surface area of threaded screws ［(31.70±0.06) mm2］ was significantly greater than that of the non-threaded ones ［(29.56±0.22) mm2］. After 8, 12 and 16 weeks, the volume loss ratios of the threaded screws were (26.01±3.44)%, (33.35±5.05)%, (36.84±6.99)%, respectively, and the volume loss ratios of the non-threaded screws were (22.53±4.78)%, (31.12±6.59)%, (43.22±9.31)%, respectively. At the same time point, there were no significant differences in the volume loss ratio between two kinds of screws. The relationship between the volume reduction and the implantation time was linear for non-threaded screws and gradually decreasing for threaded screws. Conclusions Under the low-bearing condition, different structural design for high purity magnesium screws has no obvious effect on their degradation rate in vivo.

Effects from Fiber Orientations of Bovine Pericardium on its Compression Performance / 医用生物力学

Objective To investigate the mechanical behavior of bovine pericardium with different orientations after compression and evaluate its effects on the duration of transcatheter aortic valve. Methods According to the fiber directions, the pericardial strips were divided into 12 groups of transverse, longitudinal and oblique pericardial strips, and each group included 3 strips of pericardium. One strip maintained the original state, and the other two strips were under 12.5 N and 25 N compression, respectively for 1 h. The mechanical properties of compressed samples were tested and analyzed subsequently in uniaxial tension test. Results The samples with different orientations showed obvious anisotropy before and after compression. The secant modulus, elastic modulus and ultimate tensile strength of the longitudinal pericardium were generally greater than those of the oblique pericardium, while the oblique pericardium was larger than the transverse pericardium. For longitudinal and oblique bovine pericardium under 25 N compression, the average tensile strength ratio was 0.92 and 0.87, respectively, and the ratio of tensile strength before and after compression had a significant difference (P＜0.05). The average tensile strength ratio of transverse bovine pericardium after 25 N compression was 0.97, and there was no significant difference in the ratio of tensile strength before and after compression (P＞0.05). Conclusions The compressive damage of the pericardia with different fiber orientations was very small under low stresses at transitory time. For design and production of transcatheter aortic valves, the orientations of the pericardium and the changes of strength after compression should be taken into consideration.

Bone Microstructual Changes Around the Magnesium Based-Implant after Implantation in Rabbit Femur / 医用生物力学

Objective To study the change patterns of bone microstructural parameters around the magnesium based- implants after implantation in rabbit femur at different implantation time points. Methods The threaded and non-threaded high-purity magnesium (HP Mg, 99.99 wt.%) screws, with a 2 mm diameter and a 7 mm length, were implanted into the femoral condyle of the rabbits. The control group was the drilled and healthy group. Micro-CT scanning and analysis were performed at 8th, 12th and 16th week after operation. The obtained microstructural parameters included bone mineral density (BMD), bone volume fraction (BV/TV), trabecular thickness (Tb.Th), trabecular number (Tb.N), trabecular separation (Tb.Sp). Results At 8th week, BMD and BV/TV in non-threaded magnesium screw group were significantly higher than those in healthy group, Tb.N was significantly higher than that in drilled and healthy group, and Tb.Sp was significantly lower than that in healthy group. At 12th week, BMD, BV/TV and Tb.N in threaded magnesium screw group were significantly higher than those in drilled and healthy group, Tb.Th was significantly higher than that in healthy group, and Tb.Sp was significantly lower than that in drilled and healthy group. At 16th week, BMD, BV/TV and Tb.N in non-threaded magnesium screw group were significantly higher than those in drilled and healthy group, and Tb.Sp was significantly lower than that in drilled and healthy group. Conclusions The magnesium based-implant promoted higher BMD, BV/TV, Tb.Th, Tb.N and lower Tb.Sp of surrounding implant, indicating that osseointegration and bone growth were in good condition. Magnesium based-implant could effectively promote the regeneration of bone. The results provide a theoretical basis for the orthopedic application of magnesium based-implants in clinic.