Limbal stem cells carried by a four-dimensional -printed chitosan-based scaffold for corneal epithelium injury in diabetic rabbits.

Methods: Herein, we obtained and characterized deltaN p63- and adenosine triphosphate-binding cassette subfamily G member 2-expressing limbal stem cells (LSCs). Chitosan and carboxymethyl chitosan (CTH) were cross-linked to be an in situ thermosensitive hydrogel (ACH), which was printed through four-dimensional (4D) printing to obtain a porous carrier with uniform pore diameter (4D-CTH). Rabbits were injected with alloxan to induce diabetes mellitus (DM). Following this, the LSC-carrying hydrogel was spread on the surface of the cornea of the diabetic rabbits to cure corneal epithelium injury. Results: Compared with the control group (LSCs only), rapid wound healing was observed in rabbits treated with LSC-carrying 4D-CTH. Furthermore, the test group also showed better corneal nerve repair ability. The results indicated the potential of LSC-carrying 4D-CTH in curing corneal epithelium injury. Conclusion: 4D-CTH holds potential as a useful tool for studying regenerative processes occurring during the treatment of various diabetic corneal epithelium pathologies with the use of stem cell-based technologies.

Tibial cortex transverse transport promotes ischemic diabetic foot ulcer healing via enhanced angiogenesis and inflammation modulation in a novel rat model.

BACKGROUND: Tibial Cortex Transverse Transport (TTT) represents an innovative surgical method for treating lower extremity diabetic foot ulcers (DFUs), yet its underlying mechanisms remain elusive. Establishing an animal model that closely mirrors clinical scenarios is both critical and novel for elucidating the mechanisms of TTT. METHODS: We established a diabetic rat model with induced hindlimb ischemia to mimic the clinical manifestation of DFUs. TTT was applied using an external fixator for regulated bone movement. Treatment efficacy was evaluated through wound healing assessments, histological analyses, and immunohistochemical techniques to elucidate biological processes. RESULTS: The TTT group demonstrated expedited wound healing, improved skin tissue regeneration, and diminished inflammation relative to controls. Marked neovascularization and upregulation of angiogenic factors were observed, with the HIF-1α/SDF-1/CXCR4 pathway and an increase in EPCs being pivotal in these processes. A transition toward anti-inflammatory M2 macrophages indicated TTT's immunomodulatory capacity. CONCLUSION: Our innovative rat model effectively demonstrates the therapeutic potential of TTT in treating DFUs. We identified TTT's roles in promoting angiogenesis and modulating the immune system. This paves the way for further in-depth research and potential clinical applications to improve DFU management strategies.

If we should remove internal fixation devices for rib fractures?

BACKGROUND: Internal fixation for rib fractures has been widely carried out worldwide, and its surgical efficacy has been recognized. However, there is still controversy about whether implant materials need to be removed. At present, the research on this topic is still lacking at home and abroad. Therefore, in this study, the patients undergoing removal of internal fixation for rib fractures in our department within one year were followed up, to statistically analyze implant-related complications, postoperative complications and postoperative remission rate. METHODS: A retrospective analysis was conducted on 143 patients undergoing removal of internal fixation for rib fractures from 2020 to 2021 in our center. The implant-related complications, postoperative complications and postoperative remission rate of patients with internal fixation were analyzed. RESULTS: In this study, a total of 143 patients underwent removal of internal fixation, among which 73 suffered from preoperative implant-related complications (foreign-body sensation, pain, wound numbness, sense of tightness, screw slippage, chest tightness, implant rejection), and 70 had no post operative discomfort but asked for removal of internal fixation. The average interval between rib fixation and removal was 17 ± 9.00 (months), and the average number of removed materials was 5.29 ± 2.42. Postoperative complications included wound infection (n = 1) and pulmonary embolism (n = 1). of the 73 patients with preoperative implant-related complications, the mean postoperative remission rate was 82%. Among the 70 patients without preoperative discomfort, the proportion of discomforts after removal was 10%. No perioperative death occurred. CONCLUSION: For patients with internal fixation for rib fractures, removal of internal fixation can be considered in the case of implant-related complications after surgery. The corresponding symptoms can be relieved after removal. The removal presents low complication rate, and high safety and reliability. For patients without obvious symptoms, it is safe to retain the internal fixation in the body. For the asymptomatic patients who ask for removal of internal fixation, the possible risk of complications should be fully informed before removal.

The Color Improvement of Underwater Images Based on Light Source and Detector.

As one of the most direct approaches to perceive the world, optical images can provide plenty of useful information for underwater applications. However, underwater images often present color deviation due to the light attenuation in the water, which reduces the efficiency and accuracy in underwater applications. To improve the color reproduction of underwater images, we proposed a method with adjusting the spectral component of the light source and the spectral response of the detector. Then, we built the experimental setup to study the color deviation of underwater images with different lamps and different cameras. The experimental results showed that, a) in terms of light source, the color deviation of an underwater image with warm light LED (Light Emitting Diode) (with the value of Δa*2+Δb*2 being 26.58) was the smallest compared with other lamps, b) in terms of detectors, the color deviation of images with the 3×CMOS RGB camera (a novel underwater camera with three CMOS sensors developed for suppressing the color deviation in our team) (with the value of Δa*2+Δb*2 being 25.25) was the smallest compared with other cameras. The experimental result (i.e., the result of color improvement between different lamps or between different cameras) verified our assumption that the underwater image color could be improved by adjusting the spectral component of the light source and the spectral response of the detector. Differing from the color improvement method with image processing, this color-improvement method was based on hardware, which had advantages, including more image information being retained and less-time being consumed.

Mastery of chest wall reconstruction with a titanium sternum-rib fixation system: a case series.

Background: Chest wall disease is a common disease in thoracic surgery. For most chest wall lesions, surgical resection is the mainstay of treatment. Reconstruction is indicated for a wide range of chest wall defects. Currently, various reconstruction materials are used in clinic, including 3D printing materials and various types of metal materials. At present, most of the studies using titanium sternum-rib fixation system for reconstruction are case reports. The purpose of this paper is to analyze the experience to discuss our essential surgical techniques for treating various types of chest wall reconstruction with a titanium sternum-rib fixation system over the last 5 years. Case Description: A retrospective analysis was performed on patients with chest wall tumors treated with a titanium sternum-rib fixation system in our center from 2016 to 2020. Chest wall reconstruction techniques, experiences, postoperative complications, and quality of life including chest discomfort, chronic pain, average time to return to normal life, chest wall deformity after resection for various types of chest wall tumors were analyzed. In this study, a total of 57 patients were successfully operated without chest wall deformity and return to daily life early. With an average of 2.3 ribs removed, including 10 procedures involving sternotomy and reconstruction and 3 procedures involving sternoclavicular joint resection and reconstruction. The follow-up time of the whole group ranged from 3 months to 5 years. Postoperative chest discomfort occurred in 6 patients during follow-up; 2 patients had chronic pain. The average time to return to normal life was 1.4 months. One patient developed a deformed depression of the chest wall, and 2 patients developed wound infections. There was no perioperative death. Conclusions: In our clinical experience, the titanium sternum-rib fixation system is safe, effective, and feasible. The technique is straightforward. The early and middle postoperative curative effect is satisfactory and can be used clinically.

Smooth Surface Visual Imaging Method for Eliminating High Reflection Disturbance.

At present, visual imaging is widely applied for surface defects such as bumps and scratches in the manufacture of precise parts with a highly reflective surface. However, the high light reflection and halo disturbance as a result of the illumination in visual imaging exert a direct influence on the accuracy of defect detection. In this regard, the present paper develops an adaptive illumination method based on space-time modulation for a visual imaging system. Furthermore, a digital micro-mirror device (DMD) is employed to realize the pixel-level spatiotemporal modulation of illumination. Then, in combination with the illumination intensity feedback of charge coupled device (CCD), the time-space ratio is adjusted automatically to achieve adaptive uniform illumination and effectively suppress the high light reflection and halo disturbance of highly reflective surfaces. The experimental results show that, in terms of restraining high light disturbance, the visibility and accuracy of visual imaging are improved.

Antitumor effect of hyaluronic-acid-modified chitosan nanoparticles loaded with siRNA for targeted therapy for non-small cell lung cancer.

Purpose: Nanoparticle (NP)-mediated targeted delivery of therapeutic genes or siRNAs to tumors has potential advantages. In this study, hyaluronic acid (HA)-modified chitosan nanoparticles (CS NPs-HA) loaded with cyanine 3 (Cy3)-labeled siRNA (sCS NPs-HA) were prepared and characterized. Methods: Human non-small cell lung cancer (NSCLC) A549 cells expressing receptor CD44 and tumor-bearing mice were used to evaluate the cytotoxic and antitumor effects of sCS NPs-HA in vitro and in vivo. Results: The results showed that noncytotoxic CS NPs-HA of small size (100-200 nm) effectively delivered the Cy3-labeled siRNA to A549 cells via receptor CD44 and inhibited cell proliferation by downregulating the target gene BCL2. In vivo experiment results revealed that sCS NPs-HA directly delivered greater amounts of Cy3-labeled siRNA to the tumor sites, resulting in the inhibition of tumor growth by downregulating BCL2, as compared to unmodified NPs loaded with siRNA (sCS NPs) and to naked Cy3-labeled siRNA. Conclusion: The HA-modified NPs based on chitosan could serve as a promising carrier for siRNA delivery and targeted therapy for NSCLC expressing CD44.

An in situ hydrogel based on carboxymethyl chitosan and sodium alginate dialdehyde for corneal wound healing after alkali burn.

There is currently no optimal scaffold for the transplantation of limbal stem cells (LSCs) to induce corneal reconstruction after corneal alkali burns. This study attempts to fabricate a novel in situ Alginate-Chitosan hydrogel (ACH) for LSCs transplantation. Sodium alginate dialdehyde (SAD), a biological crosslinker, was prepared by periodate-mediated sodium alginate oxidization. Carboxymethyl chitosan was rapidly crosslinked with SAD via Schiff's base formation between the available aldehyde and amino groups. The ACH is rapidly formed on the wound surface by self-crosslinking without adding any chemical crosslinking component. Gelation time, transmittance, microscopic structure, equilibrium swelling, cytotoxicity, histocompatibility and degradability of the hydrogel were all examined. Rabbit primary LSCs were encapsulated in the hydrogel and transplanted to alkali burn wounds in vivo. Cornea reconstruction was evaluated by visual observation, slit lamp, histological analysis, and immunofluorescence staining. Results showed that the in situ hydrogel was highly transparent, gelated quickly, biocompatible, and had low cytotoxicity. LSCs cultured in vitro expressed the stem marker p63 but lacked the differentiated epithelial markers cytokeratin 3 and 12. Furthermore, the hydrogel encapsulating LSCs could be formed quickly on the alkali burn wound of the cornea and was shown to significantly improve epithelial reconstruction. Taken together, treatment with this novel in situ hydrogel-mediated LSC transplantation system may serve as a rapid and effective method for corneal wound healing. © 2018 The Authors. Journal of Biomedical Materials Research Part A published by Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 742-754, 2019.