Objective To observe the effect of transplantation of embryonic stem cell(ES) on neurological functional recovery of injured spinal cord in adult mouse. Methods The ES cells were cultured and induced in vitro. Fifty C57/BL6J mice were made animal model of semicut mice of T9，10. The ES cellderived neural precursors cells were transplanted into the vertebral canalaround injured spinal cord semi-cut mice. Twenty-eight C57/BL6J mice were randomly divided into three groups: sham operation group(group A,n=9), operation／cell group (group B，n=10), and operation／DMEM group(group C,n=9). RT-PCR analysis, X-gal staining and immunofluorescence were used to observe the cells survival and differentiation in the spinal crod. BBB test was performed to study functional improvement. Results ES cells induced and cultured in vitro displayed clonal growth with circle or ovoid shape and had one or more nucleoli. RT-PCR result showed that the induced ES cells expressed mRNA of Nestin and microtubuleassociated protein, but did not express glial fibrillory acidic protein(GFAP). There was statistically significant difference in BBB scoring between group A and groups B, C after operation (P＜0.01). There was statistically significant difference in BBB scoring at 1, 2 and 4 weeks of operation(P＜0.01), but no statistically significant difference at 6 and 8 weeks of operation between groups B and C(P＞0.05). The X-gal staining results werepositive in group B and negative in groups A and C. The immunoflurescence resultshowed neurofilament green fluor and no expression of GFAP in injured spinal cord region. Conclusion After transplantation, ES cellderived cells can survive, transfer into the injury position, and differentiate into neurons, but spinal cord function has no obvious improvement.
To investigate the influence of the preload and supporting stiffness on the hearing compensation performance of round window stimulation, a coupling finite model composed of a human ear, an actuator and a support was established. This model was constructed based on a complete set of micro-computed tomography (Micro-CT) images of a healthy adult’s right ear by reverse engineering technology. The validity of the model was verified by comparing the model’s calculated results with experimental data. Based on this model, we applied different amplitude preloads on the actuator, and changed the support’s stiffness. Then, the influences of the actuator’s preload and the support’s stiffness were analyzed by comparing the corresponding displacements of the basilar membrane. The results show that after applying a preload on the actuator, its hearing compensation performance was increased at the middle and high frequencies, but was deteriorated at low frequencies; besides, compared with using the fascia as the actuator’s support in clinical practice, utilizing the titanium alloy to fabricate the support would enhance the hearing compensation performance of the round window stimulation in the whole frequency range.
In order to study the influence of tympanic membrane lesion and ossicular erosion caused by otitis media on the hearing compensation performance of round-window stimulation, a human ear finite element model including cochlear asymmetric structure was established by computed tomography (CT) technique and reverse engineering technique. The reliability of the model was verified by comparing with the published experimental data. Based on this model, the tympanic membrane lesion and ossicular erosion caused by otitis media were simulated by changing the corresponding tissue structure. Besides, these simulated diseases’ effects on the round-window stimulation were studied by comparing the corresponding basilar-membrane’s displacement at the frequency-dependent characteristic position. The results show that the thickening and the hardening of the tympanic membrane mainly deteriorated the hearing compensation performance of round-window stimulation in the low frequency; tympanic membrane perforation and the minor erosion of ossicle with ossicular chain connected slightly effected the hearing compensation performance of round-window stimulation. Whereas, different from the influence of the aforementioned lesions, the ossicular erosion involving the ossicular chain detachment increased its influence on performance of round-window stimulation at the low frequency. Therefore, the effect of otitis media on the hearing compensation performance of round-window stimulation should be considered comprehensively when designing its actuator, especially the low-frequency deterioration caused by the thickening and the hardening of the tympanic membrane; the actuator’s low-frequency output should be enhanced accordingly to ensure its postoperative hearing compensation performance.
In order to study the effect of middle ear malformations on energy absorbance, we constructed a mechanical model that can simulate the energy absorbance of the human ear based on our previous human ear finite element model. The validation of this model was confirmed by two sets of experimental data. Based on this model, three common types of middle ear malformations, i.e. incudostapedial joint defect, incus fixation and malleus fixation, and stapes fixation, were simulated by changing the structure and material properties of the corresponding tissue. Then, the effect of these three common types of middle ear malformations on energy absorbance was investigated by comparing the corresponding energy absorbance. The results showed that the incudostapedial joint defect significantly increased the energy absorbance near 1 000 Hz. The incus fixation and malleus fixation dramatically reduced the energy absorbance in the low frequency, which made the energy absorbance less than 10% at frequencies lower than 1 000 Hz. At the same time, the peak of energy absorbance shifted to the higher frequency. These two kinds of middle ear malformations had obvious characteristics in the wideband acoustic immittance test. In contrast, the stapes fixation only reduced the energy absorbance in the low frequency and increased energy absorbance in the middle frequency slightly, which had no obvious characteristic in the wideband acoustic immittance test. These results provide a theoretical reference for the wideband acoustic immittance diagnosis of middle ear malformations in clinic.
Otitis media is one of the common ear diseases, and its accurate diagnosis can prevent the deterioration of conductive hearing loss and avoid the overuse of antibiotics. At present, the diagnosis of otitis media mainly relies on the doctor's visual inspection based on the images fed back by the otoscope equipment. Due to the quality of otoscope equipment pictures and the doctor's diagnosis experience, this subjective examination has a relatively high rate of misdiagnosis. In response to this problem, this paper proposes the use of faster region convolutional neural networks to analyze clinically collected digital otoscope pictures. First, through image data enhancement and preprocessing, the number of samples in the clinical otoscope dataset was expanded. Then, according to the characteristics of the otoscope picture, the convolutional neural network was selected for feature extraction, and the feature pyramid network was added for multi-scale feature extraction to enhance the detection ability. Finally, a faster region convolutional neural network with anchor size optimization and hyperparameter adjustment was used for identification, and the effectiveness of the method was tested through a randomly selected test set. The results showed that the overall recognition accuracy of otoscope pictures in the test samples reached 91.43%. The above studies show that the proposed method effectively improves the accuracy of otoscope picture classification, and is expected to assist clinical diagnosis.
ObjectiveElectrospinning technique was used to manufacture polycaprolactone (PCL)/collagen typeⅠ nanofibers orientated patches and to study their physical and chemical characterization, discussing their feasibility as synthetic patches for rotator cuff repairing.MethodsPCL patches were prepared by electrospinning with 10% PCL electrospinning solution (control group) and PCL/collagen typeⅠorientated nanofibers patches were prepared by electrospinning with PCL electrospinning solution with 25% collagen type Ⅰ(experimental group). The morphology and microstructure of the two patches were observed by gross and scanning electron microscopy, and the diameter and porosity of the fibers were measured; the mechanical properties of the patches were tested by uniaxial tensile test; the composition of the patches was analyzed by Fourier transform infrared spectroscopy; and the contact angle of the patch surface was measured. Two kinds of patch extracts were co-cultured with the third generation of rabbit tendon stem cells. Cell counting kit 8 (CCK-8) was used to detect the toxicity and cell proliferation of the materials. Normal cultured cells were used as blank control group. Rabbit tendon stem cells were co-cultured with the two patches and stained with dead/living cells after 3 days of in vitro culture, and laser confocal scanning microscopy was used to observe the cell adhesion and activity on the patch.ResultsGross and scanning electron microscopy showed that the two patch fibers were arranged in orientation. The diameter of patch fibers in the experimental group was significantly smaller than that in the control group (t=26.907, P=0.000), while the porosity in the experimental group was significantly larger than that in the control group (t=2.506, P=0.032). The tensile strength and Young’s modulus of the patch in the experimental group were significantly higher than those in the control group (t=3.705, P=0.029; t=4.064, P=0.034). Infrared spectrum analysis showed that PCL and collagen type Ⅰ were successfully mixed in the experimental group. The surface contact angle of the patch in the experimental group was (73.88±4.97)°, which was hydrophilic, while that in the control group was (128.46±5.10) °, which was hydrophobic. There was a significant difference in the surface contact angle between the two groups (t=21.705, P=0.002). CCK-8 test showed that with the prolongation of culture time, the cell absorbance (A) value increased gradually in each group, and there was no significant difference between the experimental group and the control group at each time point (P>0.05). Laser confocal scanning microscopy showed that rabbit tendon stem cells could adhere and grow on the surface of both patches after 3 days of culture. The number of cells adhered to the surface of the patches in the experimental group was more than that in the control group, and the activity was better.ConclusionPCL/ collagen type Ⅰ nanofibers orientated patch prepared by electrospinning technology has excellent physical and chemical properties, cell adhesion, and no cytotoxicity. It can be used as an ideal scaffold material in tendon tissue engineering for rotator cuff repair in the future.