A long-term serial histological evaluation of the patellar tendon in humans after harvesting its central third

AbstractRetinal degenerative disorders, including age-related macular degeneration and retinitis pigmentosa (RP), are characterized by the irreversible loss of photoreceptor cells and retinal pigment epithelial (RPE) cells; however, the long-term effect of implanting both human induced pluripotent stem cell (hiPSC)-derived RPE and photoreceptor for retinal regeneration has not yet been investigated. In this study, we evaluated the long-term effects of hiPSC-derived RPE and photoreceptor cell transplantation in Pde6b knockout rats to study RP; cells were injected into the subretinal space of the right eyes of rats before the appearance of signs of retinal degeneration at 2–3 weeks of age. Ten months after transplantation, we evaluated the cells using fundus photography, optical coherence tomography, and histological evaluation, and no abnormal cell proliferation was observed. A relatively large number of transplanted cells persisted during the first 4 months; subsequently, the number of these cells decreased gradually. Notably, immunohistochemical analysis revealed that the hiPSC-derived retinal cells showed characteristics of both RPE cells and photoreceptors of human origin after transplantation. Functional analysis of vision by scotopic electroretinogram revealed significant preservation of vision after transplantation. Our study suggests that the transplantation of hiPSC-derived retinal cells, including RPE cells and photoreceptors, has a potential therapeutic effect against irreversible retinal degenerative diseases.

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Impact of oral contraceptive use and menstrual phases on patellar tendon morphology, biochemical composition, and biomechanical properties in female athletes

Journal of Applied Physiology ◽

10.1152/japplphysiol.01255.2012 ◽

2013 ◽

Vol 114 (8) ◽

pp. 998-1008 ◽

Cited By ~ 19

Author(s):

Mette Hansen ◽

Christian Couppe ◽

Christina S. E. Hansen ◽

Dorthe Skovgaard ◽

Vuokko Kovanen ◽

...

Keyword(s):

Patellar Tendon ◽

Female Athletes ◽

Maximum Voluntary Contraction ◽

Biomechanical Properties ◽

Cross Sectional Area ◽

Cross Linking ◽

Sectional Area ◽

Cross Sectional ◽

Collagen Cross Linking

Sex differences exist with regards to ligament and tendon injuries. Lower collagen synthesis has been observed in exercising women vs. men, and in users of oral contraceptives (OC) vs. nonusers, but it is unknown if OC will influence tendon biomechanics of women undergoing regular training. Thirty female athletes (handball players, 18–30 yr) were recruited: 15 long-term users of OC (7.0 ± 0.6 yr) and 15 nonusers (>5 yr). Synchronized values of patellar tendon elongation (obtained by ultrasonography) and tendon force were sampled during ramped isometric knee extensor maximum voluntary contraction to estimate mechanical tendon properties. Furthermore, tendon cross-sectional area and length were measured from MRI images, and tendon biopsies were obtained for analysis of tendon fibril characteristics and collagen cross-linking. Overall, no difference in tendon biomechanical properties, tendon fibril characteristics, or collagen cross-linking was observed between the OC users and nonusers, or between the different phases of the menstrual cycle. In athletes, tendon cross-sectional area in the preferred jumping leg tended to be larger than that in the contralateral leg ( P = 0.09), and a greater absolute ( P = 0.01) and normalized tendon stiffness ( P = 0.02), as well as a lower strain ( P = 0.04), were observed in the jumping leg compared with the contralateral leg. The results indicate that long-term OC use or menstrual phases does not influence structure or mechanical properties of the patellar tendon in female team handball athletes.

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Intramuscular Injection of Botox Induces Tendon Atrophy and Senescence of Tendon-Derived Stem Cells

10.21203/rs.3.rs-70180/v1 ◽

2020 ◽

Author(s):

Peilin Chen ◽

Ziming Chen ◽

Christopher Mitchell ◽

Junjie Gao ◽

Lianzhi Chen ◽

...

Keyword(s):

Stem Cells ◽

Mechanical Loading ◽

Patellar Tendon ◽

Intramuscular Injection ◽

Vastus Lateralis ◽

Collagen Fibre ◽

Differentiation Capacity ◽

Botox Injection

Abstract Background: Botulinum toxin (Botox) injection is in widespread clinical use for the treatment of muscle spasms and tendinopathy but the mechanism of action is poorly understood. Hypothesis: We hypothesised that the reduction of patellar-tendon mechanical-loading following intra-muscular injection of Botox results in tendon atrophy that is at least in part mediated by the induction of senescence of tendon-derived stem cells (TDSCs). Study Design: Controlled laboratory study Methods: A total of 36 mice were randomly divided in 2 groups (18 Botox-injected and 18 vehicle-only control). Mice were injected into to right vastus lateralis of quadriceps muscles either with Botox to induce mechanical stress deprivation of the patellar tendon or with normal saline as control. At 2 weeks post-injection, animals were euthanized prior to tissues harvest for either evaluation of tendon morphology or in vitro studies. TDSCs were isolated by cell-sorting prior to determination of viability, differentiation capacity and senescence markers, as well as assessing their response to mechanical loading in a bioreactor. Finally, to examine the mechanism of tendon atrophy in vitro, key proteins in the PTEN/AKT pathway were evaluated in TDSCs in both groups. Results: Two weeks after Botox injection, patellar tendons displayed atrophic features including tissue volume reduction and collagen fibre misalignment and increased degradation. The colony formation assay revealed the significantly reduced colony units of TDSCs in Botox injected group compared to controls. Multipotent differentiation capacity of TDSCs has also diminished after Botox injection. To examine if mechanical deprived TDSC is capable of forming tendon tissue, we used an isolated bioreactor system to culture 3D TDSCs constructs. The result showed that TDSCs from the Botox-treated group failed to restore tenogenic differentiation after appropriate mechanical loading. Examination of PTEN/AKT signalling pathway revealed that injection of Botox into quadriceps muscle causes PTEN/AKT mediated cell senescence of TDSCs. Conclusion: Intramuscular injection of Botox interferes with tendon homeostasis by inducing tendon atrophy and senescence of TDSCs. Botox injection may have long-term adverse consequences for the treatment of tendinopathy. Clinical relevance: Intramuscular Botox injection for tendinopathy and tendon injury could cause adverse effects in human tendons and re-evaluation of its long-term efficacy is warranted.

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Changes in the mechanical properties of patellar tendon preparations of spontaneously diabetic dogs under long-term insulin therapy

Journal of Biomechanics ◽

10.1016/0021-9290(94)90228-3 ◽

1994 ◽

Vol 27 (8) ◽

pp. 1105-1108 ◽

Cited By ~ 13

Author(s):

Ronald L. Lancaster ◽

Roger C. Haut ◽

Charles E. DeCamp

Keyword(s):

Mechanical Properties ◽

Insulin Therapy ◽

Patellar Tendon ◽

Diabetic Dogs

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LONG-TERM CLINICAL AND HISTOLOGICAL EVALUATION OF BIOCERAMIC TOTAL HIP ENDOPROSTHESES

Orthopedics ◽

10.3928/0147-7447-19811101-04 ◽

1981 ◽

Vol 4 (11) ◽

pp. 1231-1240

Author(s):

Martin Salzer ◽

Karl Knahr ◽

H Plenk

Keyword(s):

Histological Evaluation ◽

Total Hip

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Short and long term clinical and histological evaluation of medium-depth chemical facial peel with 35°/o trichloroacetic acid on photo damaged skin

Ain Shams Journal of Surgery ◽

10.21608/asjs.2014.179131 ◽

2014 ◽

Vol 13 (2) ◽

pp. 415-424

Author(s):

Sherien Metwally Salama ◽

Mohamed Saber Mohamed

Keyword(s):

Trichloroacetic Acid ◽

Histological Evaluation ◽

Short And Long Term

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Safety and effectiveness of a novel generator algorithm for bipolar vessel sealing: a randomised controlled chronic animal study

BMC Surgery ◽

10.1186/s12893-019-0625-2 ◽

2019 ◽

Vol 19 (1) ◽

Author(s):

Bernhard Kraemer ◽

Christos Tsaousidis ◽

Stephan Kruck ◽

Martin Schenk ◽

Marcus Scharpf ◽

...

Keyword(s):

Animal Study ◽

Clinical Success ◽

Lateral Spread ◽

Histological Evaluation ◽

Vascular Bundles ◽

The Novel ◽

Success Rates ◽

Vessel Sealing ◽

Thermal Spread

Abstract Background Electrosurgical vessel sealers are gradually replacing conventional techniques such as ligation and clipping. Algorithms that control electrosurgical units (ESU), known as modes, are important for applications in different surgical disciplines. This chronic porcine animal study aimed to evaluate the safety and effectiveness of the novel thermoSEAL electrosurgical vessel sealing mode (TSM). The BiClamp® mode (BCM) of the renowned VIO® 300 D ESU served as control. BCM has been widely available since 2002 and has since been successfully used in many surgical disciplines. The TSM, for the novel VIO® 3 ESU, was developed to reduce sealing time and/or thermal lateral spread adjacent to the seal while maintaining clinical success rates. The primary aim of this study was to investigate the long-term and intraoperative seal quality of TSM. Methods The BiCision® device was used for vessel sealing with TSM and BCM in ten German Landrace pigs which underwent splenectomy and unilateral nephrectomy during the first intervention of the study. The seals were cut with the BiCision® knife. Ninety-nine arteries, veins and vascular bundles were chronically sealed for 5 or 21 days. Thereafter, during the second and terminal intervention of the study, 97 additional arteries and veins were sealed. The carotid arteries were used for histological evaluation of thermal spread. Results After each survival period, no long-term complications occurred with either mode. The intraoperative seal failure rates, i.e. vessel leaking or residual blood flow after the first sealing activation, were 2% with TSM versus 6% with BCM (p = 0.28). The sealing time was significantly shorter with TSM (3.5 ± 0.69 s vs. 7.3 ± 1.3 s, p < 0.0001). The thermal spread and burst pressure of arteries sealed with both modes were similar (p = 0.18 and p = 0.61) and corresponded to the histological evaluation. The measured tissue sticking parameter was rare with both modes (p = 0.33). Tissue charring did not occur. Regarding the cut quality, 97% of the seals were severed in the first and 3% in the second attempt (both with TSM and BCM). Conclusions The novel TSM seals blood vessels twice as fast as the BCM while maintaining excellent tissue effect and clinical success rates. Trial registration Not applicable.

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