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2021 ◽  
Vol 10 (21) ◽  
pp. 4928
Author(s):  
Lovepreet K. Mann ◽  
Jong Hak Won ◽  
Rajan Patel ◽  
Eric P. Bergh ◽  
Jeannine Garnett ◽  
...  

Objectives: Use of off-label tissue graft materials, such as acellular dermal matrix (ADM), for in utero repair of severe spina bifida (SB), where primary skin layer closure is not possible, is associated with poor neurological outcomes. The cryopreserved human umbilical cord (HUC) patch has regenerative, anti-inflammatory, and anti-scarring properties, and provides watertight SB repair. We tested the hypothesis that the HUC is a superior skin patch to ADM for reducing inflammation at the repair site and preserving spinal cord function. Methods: In timed-pregnant ewes with twins, on gestational day (GD) 75, spina bifida was created without a myelotomy (functional model). On GD 95, repair was performed using HUC vs. ADM patches (randomly assigned) by suturing them to the skin edges. Additionally, full thickness skin closure as a primary skin closure (PSC) served as a positive control. Delivery was performed on GD 140, followed by blinded to treatment neurological assessments of the lambs using the Texas Spinal Cord Injury Scale (TSCIS) for gait, proprioception, and nociception. Lambs without spina bifida were used as controls (CTL). Ex vivo magnetic resonance imaging of spines at the repair site were performed, followed by quantitative pathological assessments. Histological assessments (blinded) included Masson’s trichrome, and immunofluorescence for myeloperoxidase (MPO; neutrophils) and for reactive astrocytes (inflammation) by co-staining vimentin and GFAP. Results: The combined hind limbs’ TSCIS was significantly higher in the HUC group than in ADM and PSC groups, p = 0.007. Both ADM and PSC groups exhibited loss of proprioception and mild to moderate ataxia compared to controls. MRI showed increased pathological findings in the PSC group when compared to the HUC group, p = 0.045. Histologically, the meningeal layer was thickened (inflammation) by 2–3 fold in ADM and PSC groups when compared to HUC and CTL groups, p = 0.01. There was lower MPO positive cells in the HUC group than in the ADM group, p = 0.018. Posterior column astrocyte activation was increased in ADM and PSC lambs compared to HUC lambs, p = 0.03. Conclusion: The HUC as a skin patch for in utero spina bifida repair preserves spinal cord function by reducing underlying inflammation when compared to ADM.


2021 ◽  
Vol 7 (27) ◽  
pp. eabg1969
Author(s):  
Stine Lauritzen Sønder ◽  
Swantje Christin Häger ◽  
Anne Sofie Busk Heitmann ◽  
Lisa B. Frankel ◽  
Catarina Dias ◽  
...  

The plasma membrane shapes and protects the eukaryotic cell from its surroundings and is crucial for cell life. Although initial repair mechanisms to reseal injured membranes are well established, less is known about how cells restructure damaged membranes in the aftermath to restore homeostasis. Here, we show that cells respond to plasma membrane injury by activating proteins associated with macropinocytosis specifically at the damaged membrane. Subsequent to membrane resealing, cells form large macropinosomes originating from the repair site, which eventually become positive for autophagy-related LC3B protein. This process occurs independent of ULK1, ATG13, and WIPI2 but dependent on ATG7, p62, and Rubicon. Internalized macropinosomes shrink in the cytoplasm, likely by osmotic draining, and eventually fuse with lysosomes. We propose that a form of macropinocytosis coupled to noncanonical autophagy, which we term LC3-associated macropinocytosis (LAM) functions to remove damaged material from the plasma membrane and restore membrane integrity upon injury.


Author(s):  
Sven Maier ◽  
Friedhelm Beyersdorf ◽  
Christoph Benk
Keyword(s):  

A correction to this paper has been published: https://doi.org/10.1007/s10047-021-01280-6


2021 ◽  
Author(s):  
Yoo-Sun Won ◽  
Jae Sung Lee ◽  
Hyoung-Seok Jung ◽  
Ye-Hoon Jang ◽  
Chan-Woo Jung ◽  
...  

Abstract Background: Rotator cuff repair is a widely performed surgery, with the re-tear rate reportedly above 20%. To protect the repair site, patients are instructed to wear braces for 4-6 weeks, but the compliance is known to be poor. This study aimed to identify the risk factors for poor compliance and to determine whether poor compliance leads to complications such as re-tears. Additionally, we planned to determine the patients’ subjective factors for self-removal of the brace.Method: This study included 101 patients who underwent rotator cuff repair between June 2019 and August 2020. The patients could select from two types of braces, namely, the sling-type and hard-type abduction brace. They were then instructed to wear the brace for 6 weeks postoperatively. During the follow-up, ultrasonography was performed to evaluate the repair site, and a questionnaire was administered to evaluate the compliance. Result: The participants were categorized into three groups (Groups A, B, and C) according to the degree of self-removal. Compliance was found to be poor, and only 35 patients met the standard of Group A. There were no statistically significant patient factors affecting the compliance. Re-tears were noted in 4 patients. Only the surgery type (open versus arthroscopic surgery) was a statistically significant factor for re-tears. Among the subjective factors, discomfort while sleeping was the most common complaint and the most common reason for the actual removal of the brace.Conclusion: Although the risk factors for self-removal of the braces could not be identified clearly and statistically, catastrophic re-tears requiring re-operation were observed in patients with poor compliance. For better compliance, the postoperative guidelines and education of the patients should be reviewed. Furthermore, the braces need to be modified to a more comfortable design.


2021 ◽  
Author(s):  
Jessica E Ackerman ◽  
Katherine T Best ◽  
Samantha N Muscat ◽  
Chia-Lung Wu ◽  
Alayna E Loiselle

The tendon healing process is regulated by the coordinated interaction of multiple cell types and molecular processes. However, these processes are not well-defined leading to a paucity of therapeutic approaches to enhance tendon healing. Scleraxis-lineage (ScxLin) cells are the major cellular component of adult tendon and make time-dependent contributions to the healing process. Prior work from our lab and others suggests heterogeneity within the broader ScxLin population over the course of tendon healing; therefore delineating the temporal and spatial contributions of these cells is critical to understanding and improving the healing process. In the present study we utilize lineage tracing of the adult ScxLin population to determine whether these cells undergo cellular activation and subsequent myofibroblast differentiation, which is associated with both proper healing and fibrotic progression in many tissues. We show that adult ScxLin cells undergo transient activation in the organized cellular bridge at the tendon repair site, contribute to the formation of an organized neo-tendon, and contribute to a persistent myofibroblast population in the native tendon stubs. The mechanisms dictating this highly specialized spatial response are unknown. We therefore utilized spatial transcriptomics to better define the spatio-molecular program of tendon healing. Integrated transcriptomic analyses across the healing time-course identifies five distinct molecular regions, including key interactions between the inflammatory bridging tissue and highly reactive tendon tissue at the repair site, with adult ScxLin cells being a central player in the transition from native tendon to reactive, remodeling tendon. Collectively, these data provide important insights into both the role of adult ScxLin cells during healing as well as the molecular mechanisms that underpin and coordinate the temporal and spatial healing phenotype, which can be leveraged to enhance the healing process.


2021 ◽  
pp. 175319342110183
Author(s):  
Ya Fang Wu ◽  
Jin Bo Tang

We assessed the effects of tendon core sutures' transverse components on the tensile resistance of two commonly used 6-strand tendon repairs. Tang and Yoshizu #1 repairs (6-strand) were tested and compared with 4-strand rectangular and double Kessler sutures (4-strand). A total of 40 pig flexor tendons were tested under cyclic loading. We recorded the number of tendons that formed a 2-mm gap between two tendon ends during 20 cycles of cyclic loading test, stiffness at the 1st and 20th loading cycle, and gap distance at the repair site and the ultimate repair strength at the 20th cycles. We found that the Yoshizu #1 repairs were more prone to form gaps and their ultimate strength was significantly lower than that of the Tang repair. The transverse components in a 6-strand repair affect gap formation and failure strength.


2021 ◽  
pp. 175319342110183
Author(s):  
Ya Fang Wu ◽  
Wei Feng Mao ◽  
Jin Bo Tang

We investigated the effects of the transverse components of a tendon core suture on tensile resistance and strength of 4-strand repairs. Forty-four pig flexor tendons were repaired with one of the following four methods: double Tsuge, U-shaped, 4-strand cross and 4-strand rectangular repairs. We recorded the number of the repaired tendons that formed a 2 mm gap between the tendon ends during cyclic loading for 20 cycles, stiffness of the tendon at the 1st and 20th cycle, gap distance at the repair site and ultimate strength of the repair at the 20th cycle. When transverse components were added to the core suture, a greater number of tendons formed a 2 mm gap during cyclic loading. The stiffness gradually decreased, and the repair site's gap distance after cyclic loading increased with the presence of transverse components of the sutures. We conclude that the core suture's transverse components negatively impact the tensile resistance of 4-strand tendon repairs.


Author(s):  
Chiara P. Curcillo ◽  
Daniel J. Duffy ◽  
Yi-Jen Chang ◽  
George E. Moore

Abstract Objective This study aimed to evaluate the effect of increasing the number of suture strands traversing the transection site, level of suture purchase and depth of suture penetrance on the biomechanical properties of repaired gastrocnemius tendons. Study Design Thirty-eight adult cadaveric gastrocnemius tendons were randomized, transected and repaired with either two-, four- or six-strand locking multi-level repair. Tensile loads required to create a 1 and 3 mm gap, yield, peak and failure loads and failure mode were analysed. Significance was set at p < 0.05. Results Mean ± standard deviation yield, peak and failure force for six-strand repairs was 90.6 ± 22.1 N, 111.4 ± 15.2 N and 110.3 ± 15.1 N respectively. This was significantly greater compared with both four-strand (55.0 ± 8.9 N, 72.9 ± 7.8 N and 72.1 ± 8.2 N) and two-strand repairs (24.7 ± 8.3 N, 36.5 ± 6.0 N and 36.1 ± 6.3 N) respectively (p < 0.001). Occurrence of 3 mm gap formation was significantly less using six-strand repairs (p < 0.001). Mode of failure did not differ between groups with all repairs (36/36; 100%) failing by suture pull-through. Conclusion Pattern modification by increasing the number of suture strands crossing the repair site, increasing points of suture purchase from the transection site and depth of suture penetrance is positively correlated with repair site strength while significantly reducing the occurrence of gap formation in a canine cadaveric model. Additional studies in vivo are recommended to evaluate their effect on tendinous healing, blood supply and glide resistance prior to clinical implementation.


Author(s):  
C. Njoku ◽  
C. N. Mbah ◽  
O. Elom ◽  
J. O. Agwu

The study was conducted to evaluate the effect of mechanic village on selected soil physico-chemical properties and heavy metals content in Abakaliki Southeastern Nigeria. Five replicate soil samples were collected from arable land (Control), lorry automobile repair site (Lorry), motorcycle automobile repair site,(motorcycle) car and bus repair site(car and bus),  automobile spare parts market (spare parts). These samples were taken to laboratory for the determination of selected soil physico-chemical properties and heavy metal content. The data obtained from this research was analysed using analysis of variance (ANOVA) based on CRD and difference between treatment means were dictated using F-LSD at P < 0.05. The result showed significantly (p < 0.05) adverse effect among the different automobile locations studied with respect to control in bulk density, total porosity, mean weight diameter and aggregate stability. The chemical properties of soils of mechanic village were also significantly adversely affected by mechanic village. The observed heavy metals in mechanic village were higher than the recommended ranges in soils. Therefore, it advisable that some agronomical practices that could increase the nutrients and lower the heavy metals level should be employed in order to get high crop yield and safe produce.


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