OBJECTIVE: To investigate the hemodynamic changes of the end-to-end anastomosed arteries with nitinol clips. METHODS: Fifteen New Zealand rabbits were divided into anastomosis clip group, suture group and control group randomly. The carotid arteries were resected and end-to-end anastomosis were carried out with nitinol clips in anastomosis clip group and with traditional suture in suture group. The carotid arteries remained undamaged in control group. On the days of 3, 9, 21 and 30 postoperatively, mean blood velocity (Vm), pulsatility index (PI) and resistance index (RI) of anastomosed arteries were determined by Ultrasonography Doppler. RESULTS: On the days of 8 and 9 postoperatively, there were no significant differences of VM, PI and RI between two experimental groups (P gt; 0.05). On the days of 20 and 30 postoperatively, the differences of Vm and RI were significant (Vm: P lt; 0.01, P lt; 0.05: RI: P lt; 0.01, P lt; 0.05). The hemodynamic restoration of the anastomosis clip group was better than that of the suture group. CONCLUSION: The hemodynamics of arteries anastomosed with nitinol clips is better than that with traditional suture. This technique has practical value clinically.
The transmission and interaction of neural information between the hippocampus and the prefrontal cortex play an important role in learning and memory. However, the specific effects of learning memory-related tasks on the connectivity characteristics between these two brain regions remain inadequately understood. This study employed in vivo microelectrode recording to obtain local field potentials (LFPs) from the ventral hippocampus (vHPC) and medial prefrontal cortex (mPFC) in eight rats during the performance of a T-maze task, assessed both before and after task learning. Additionally, dynamic causal modeling (DCM) was utilized to analyze alterations in causal connectivity between the vHPC and the mPFC during memory task execution pre- and post-learning. Results indicated the presence of forward connections from vHPC to mPFC and backward connections from mPFC to vHPC during the T-maze task. Moreover, the forward connection between these brain regions was slightly enhanced after task learning, whereas the backward connection was diminished. These changes in connectivity corresponded with the observed trends when the rats correctly performed the T-maze task. In conclusion, this study may facilitate future investigations into the underlying mechanisms of learning and memory from the perspective of connectivity characteristics between distinct brain regions.
Objective To evaluate the histocompatibil ity of porous hydroxyapatite (HAP) coating NiTi shape memory alloy and to provide a theoretical basis for its cl inical appl ication in bone defect repair. Methods Twenty-four Chinchilla rabbits weighing 2.0-2.5 kg were randomized into experimental group and control group (n=12). HAP coating NiTi shape memory alloy was implanted into the distal part of left femur of 12 rabbits in the experimental group, while holes without alloy implantation were performed on the control group. At 7, 14, 28 and 56 days after implantation, the animals werekilled (3 rabbits in each group at a time). Gross observation, histology observation, BMP-2 immunohistochemistry observation and image grey scale analysis were performed. And the histology observation was evaluated by GB/T16886.6-1997 in terms of inflammation, capsule wall of fibrous tissue, materials degradation and the response of peripheral tissue. Results All of the animals survived until being killed. The implants reached a peak embedded in bone tissue wholly, without loosening and bone absorption. The inflammatory cell infiltration and fibrous hyperplasia were at 7 days after implantation, with the formation of cyst wall of fibrous tissue and the implant wrapped by the cyst wall. The response of connective tissue proliferation was still obvious in partial samples of experimental group at 56 days after implantation, which was wrose than the control group but consistent with the in vivo implantation standard of GB/T16886.6-1997. Immunohistochemistry observation displayed the endogenous BMP-2 were in the cytoplasm of MSCs and osteoblast. The result of image analysis showed the expression of BMP-2 were staged in line with the repair of bone defect, two groups witnessed the peak expression of the BMP-2 at 14 days after implantation. There wereno significant differences among different time points in the staining gray scale of BMP-2 (P gt; 0.05). Conclusion HAP coating NiTi shape memory alloy, as a biomedical material, has excellent histocompatibility with bone.
The task of automatic generation of medical image reports faces various challenges, such as diverse types of diseases and a lack of professionalism and fluency in report descriptions. To address these issues, this paper proposes a multimodal medical imaging report based on memory drive method (mMIRmd). Firstly, a hierarchical vision transformer using shifted windows (Swin-Transformer) is utilized to extract multi-perspective visual features of patient medical images, and semantic features of textual medical history information are extracted using bidirectional encoder representations from transformers (BERT). Subsequently, the visual and semantic features are integrated to enhance the model's ability to recognize different disease types. Furthermore, a medical text pre-trained word vector dictionary is employed to encode labels of visual features, thereby enhancing the professionalism of the generated reports. Finally, a memory driven module is introduced in the decoder, addressing long-distance dependencies in medical image data. This study is validated on the chest X-ray dataset collected at Indiana University (IU X-Ray) and the medical information mart for intensive care chest x-ray (MIMIC-CXR) released by the Massachusetts Institute of Technology and Massachusetts General Hospital. Experimental results indicate that the proposed method can better focus on the affected areas, improve the accuracy and fluency of report generation, and assist radiologists in quickly completing medical image report writing.
ObjectiveTo investigate the technique and short-term effectiveness of the umbrella-shaped memory alloy femoral head support device (umbrella-shaped support device for short) for the treatment of avascular necrosis of femoral head (ANFH). MethodsThe umbrella-shaped support device was fabricated with Ni-Ti alloy, and its biomechanics characteristics were tested by three-dimensional finite element analysis with pro/mechanica software. Between October 2009 and December 2012, 10 patients (18 hips) with ANFH were treated. There were 7 males (12 hips) and 3 females (6 hips), aged 21-53 years (mean, 40.6 years). The disease duration was 1-5 years (mean, 3.3 years). According to Ficat staged criteria, 10 hips were rated as stage Ⅱ, 6 hips as stage Ⅲ, and 2 hips as stage IV. Microtrauma methods were used to erase the necrotic tissue of the femoral head, and the umbrella-shaped support device, autogenous iliac bone graft, and artificial bone were implanted to support the collapsed femoral head. ResultsThree-dimensional finite element analysis showed that the largest stress of umbrella-shaped support device was 1 500 MPa and the largest displacement was 1.75 mm. Operation was successfully completed in the other 10 patients (17 hips) except 1 failure hip (total hip arthroplasty was performed after 6 months). The average follow-up period was 19.7 months (range, 15-26 months). At last follow-up, the results were excellent in 5 hips, good in 9 hips, fair in 2 hips, and poor in 1 hip; the excellent and good rate was 82.35%. The Ficat stage had no change when compared with preoperative stages. ConclusionThe advantages of the umbrella-shaped support device for the treatment of ANFH are to thoroughly remove the sequestrum, to rebuild blood circulation of the femoral head, to increase the machinery supporting of subchondral bone in weight-bearing area of femoral head, and to decrease the localized stress, and it has good short-term effectiveness, but long-term effectiveness needs further observation.
Objective To investigate the changes of cognitive function of epileptic patients after antiepileptic drugs (AEDs) therapy. Methods Twenty eight cases of epileptic patients with new diagnosis and untreatment from March 2015 to February 2016 were collected. According to the seizure type, degree of attack and drug efficacy, patients were divided into three groups and treated with one of three AEDs, including Lamotrigine (LTG), Oxcarbazepine (OXC), and Sodium valproate (VPA). Among them, 11 were LTG group, 12 were OXC group and 5 were VPA group.Then the patients were followed up for 1 year. The clinical memory scale was used to analyze cognitive function of epileptic patients before and after therapy. Results Compared to 30 cases of healthy volunteers, the scores of memory quotient (P<0.01), directed memory (P<0.05), associative learning (P<0.05) and image free recall (P<0.01) of epileptic patients were obviously decreased before AEDs therapy.AEDs therapy reduced or controlled seizures in new diagnostic epileptic patients, and the total effective rate was 85.7%. In the clinical memory scale tests, the scores of memory quotient (P<0.01), directed memory (P<0.05), associative learning (P<0.05), portrait characteristics contact memory (P<0.05) were improved after therapy. The scores of image free recall and meaningless graphics recognition were also improved, but there was no statistical significance. Besides, there was a statistically significant improvement in the score of portrait characteristics contact memory after LTG treatment (P<0.05), and directed memory after VPA treatment (P<0.05). Conclusions Epileptic patients accompanied with cognitive deficits before drug intervention. Through standard AEDs treatment, seizures could be better controlled. The cognitive function of epileptic patients was not declined after short-term（within 1 year） intervention of LTG, OCX or VPA. Moreover some parts of the cognitive domain could be improved.
Objective To investigate the detailed biomechanics of TiNi shape-memory sawtooth-arm embracing plate (TiNi SMA) by comparing with l imited-contact dynamic compression plate (LC-DCP) and static interlocking intramedullary nail (SIiN), so as to provide theoretical evidence for cl inical appl ication. Methods Eight paired cadaveric femurs immersed in formaldehyde were harvested from eight specimens of adults. After making X-ray films and modeling midpiece transverse fracture, one side randomly was fixed by TiNi SMA (group A) and SIiN (group C) orderly, the other side was fixed by LC-DCP (group B). The axial compression, three-point bending (pressed from plate side and opposite side both of group A and group B, from inside of group C), and torsion were tested, and the stress shielding rate was compared. Results At every classified axial compression load, the strains of group A were greater than those of group B and group C (P lt; 0.05), the displacements of group A were greater than those of group B and group C (P lt; 0.05) except 100 N. At every classified three-point bending moment, the displacement of group A were greater than those of group B and group C pressed both from two sides, but there was no difference when pressing from two sides under the same load of group A (P gt; 0.05). At every torsion moment, the torsion angels of group A were greater than those of group B (P lt; 0.05), but equal to those of group C (P gt; 0.05). At 600 N of axial compression load, the stress shielding rates of groups A, B, C were 48.30% ± 22.99%, 89.21% ± 8.97%, 95.00% ± 3.15%, respectively, group A was significantly less than group B and group C (P lt; 0.01). Conclusion The anti-bending abil ity of TiNi SMA is weaker than LC-DCP and SIiN; the anti-torsion abil ity of TiNi SMA is weaker than SIiN, but TiNi SMA is a center-type internal fixation, the superior stress shielding rate and micromovement promote the stress stimulation of fracture, which makes it an ideal internal fixation device.
ObjectiveTo evaluate the effect of nickel-titanium three-dimensional memory alloy mesh combined with autologous bone for living model of canine tibial plateau collapse fracture by biomechanical testing. MethodsSixteen healthy 12-month-old Beagle dogs were randomly divided into 4 group, 4 dogs in each group. The dogs were used to establish the tibial plateau collapse fracture model in groups A, B, and C. Then, the nickel-titanium three-dimensional memory alloy mesh combined with autologous bone (the fibula cortical bone particles), the artificial bone (nano-hydroxyapatite), and autologous fibula cortical bone particles were implanted to repair the bone defects within 4 hours after modeling in groups A, B, and C, respectively; and the plate and screws were fixed outside the bone defects. The dogs were not treated in group D, as normal control. At 5 months after operation, all animals were sacrificed and the tibial specimens were harvested and observed visually. The destructive axial compression experiments were carried out by the biomechanical testing machine. The displacement and the maximum failure load were recorded and the axial stiffness was calculated. ResultsAll animals stayed alive after operation, and all incisions healed. After 1-3 days of operation, the animals could stand and move, and no obvious limb deformity was found. The articular surfaces of the tibial plateau specimens were completely smooth at 5 months after operation. No obvious articular surface collapse was observed. The displacement and maximum failure load of specimens in groups A and D were significantly higher than those in groups B and C (P<0.05). But no significant difference was found between groups A and D and between groups B and C (P>0.05). ConclusionThe nickel-titanium three-dimensional memory alloy mesh combined with autologous bone for subarticular bone defect of tibial plateau in dogs has good biomechanical properties at 5 months after operation, and has better axial stiffness when compared with the artificial bone and autologous bone graft.
ObjectiveTo evaluate the effectiveness of nitinol memory alloy two foot fixator combined with Kirschner wire in the treatment of trans-scaphoid perilunate dislocation.MethodsBetween September 2011 and October 2018, 17 patients with trans-scaphoid perilunate dislocation were treated with nitinol memory alloy two foot fixator and Kirschner wire. There were 12 males and 5 females, with an average age of 32.6 years (range, 23-52 years). The disease duration was 8 hours to 9 days, with an average of 6.5 days. The causes of injury included 6 cases of falling injury, 4 cases of traffic accident injury, 3 cases of stress injury of wrist caused by sports, 2 cases of violent injury of wrist caused by machine impact, 1 case of military training injury, and 1 case of other injury. One case was complicated with nerve injury. According to Herbert’s classification, all the fractures were type B4. At 1 week before operation, 3 months, 6 months after operation and last follow-up, the wrist function was evaluated according to the Krimmer scale score.ResultsAll the 17 patients were followed up 10.5-48 months, with an average of 18.6 months. There was no loosening or infection of the internal fixator, no necrosis of the scaphoid and lunate. The periosteal dislocations of the patients were well reduced and the scaphoid fractures all healed. The healing time was 4-18 months, with an average of 11.3 months. The Krimmer wrist scores were 37.5±4.4, 61.3±7.2, 83.3±9.3, 87.3±8.2 at 1 week before operation, 3 months, 6 months after operation and last follow-up, respectively. The Krimmer wrist score at each time point after operation was significantly improved when compared with that before operation (P<0.05), and at 6 months after operation and last follow-up than at 3 months after operation (P<0.05). There was no significant difference between at 6 months and last follow-up (P>0.05). At last follow-up, the Krimmer wrist function was excellent in 13 cases, good in 2 cases, fair in 1 case, poor in 1 case, and the excellent and good rate was 88.23%.ConclusionNitinol memory alloy two foot fixator combined with Kirschner wire in the treatment of trans-scaphoid periosteal dislocation has definite effectiveness, simple operation, and good recovery of wrist function after operation.