scholarly journals Analysis of “old” proteins unmasks dynamic gradient of cartilage turnover in human limbs

2019 ◽  
Vol 5 (10) ◽  
pp. eaax3203 ◽  
Author(s):  
Ming-Feng Hsueh ◽  
Patrik Önnerfjord ◽  
Michael P. Bolognesi ◽  
Mark E. Easley ◽  
Virginia B. Kraus
Keyword(s):  
Lower Limb ◽  
Protein Turnover ◽  
Limb Regeneration ◽  
Molecular Clocks ◽  
Repair Capacity ◽  
Insoluble Collagen ◽  
Potential Link ◽  
Joint Repair ◽  
Human Limb ◽  
Cartilage Turnover

Unlike highly regenerative animals, such as axolotls, humans are believed to be unable to counteract cumulative damage, such as repetitive joint use and injury that lead to the breakdown of cartilage and the development of osteoarthritis. Turnover of insoluble collagen has been suggested to be very limited in human adult cartilage. The goal of this study was to explore protein turnover in articular cartilage from human lower limb joints. Analyzing molecular clocks in the form of nonenzymatically deamidated proteins, we unmasked a position-dependent gradient (distal high, proximal low) of protein turnover, indicative of a gradient of tissue anabolism reflecting innate tissue repair capacity in human lower limb cartilages that is associated with expression of limb-regenerative microRNAs. This association shows a potential link to a capacity, albeit limited, for regeneration that might be exploited to enhance joint repair and establish a basis for human limb regeneration.

Bilateral asymmetries in professional cyclists during a Grand Tour

2020 ◽  
pp. 1-7
Author(s):  
Alejandro Javaloyes ◽  
Manuel Mateo-March ◽  
Felipe P. Carpes ◽  
Manuel Moya-Ramon ◽  
Raúl Lopez-Grueso ◽  
...  
Keyword(s):  
Injury Prevention ◽  
Intensity Distribution ◽  
Power Output ◽  
Lower Limb ◽  
Overuse Injury ◽  
Power Balance ◽  
Grand Tour ◽  
Race Time ◽  
Potential Link

BACKGROUND: Pedalling asymmetries are a topic of interest to cycling coaches and athletes due to a potential link with performance and injury prevention. OBJECTIVES: The aim of this study is to describe the bilateral asymmetry of professional cyclists during two editions of a Grand Tour. METHODS: Here we set out to determine the power balance (power produced by each lower limb) between stronger and weaker leg (dominant vs. non-dominant) of 12 UCI professional cyclists competing at two Giro d’Italia editions. Power data were recorded during competition stages. Further analysis considered power data clustered into individual intensity zones (from Z1 to Z7). RESULTS: Higher intensity elicited better power balance (lower asymmetry) regardless of the stage profile. Intensity distribution analysed according to the role of the cyclist was lower for climbers in Z2 (p= 0.006) and Z7 (p= 0.002) and higher in Z5 (p= 0.023) compared to team helpers. Power balance ranged from 0 to 9 % across the different athletes. CONCLUSIONS: Increase in power output improves power balance, especially in team helpers, and the lower power balance at lower exercise intensities, which are most of the race time, may elicit significant cumulative loading on a given leg of the cyclists, which requires further attention regarding risks of overuse injury.

scholarly journals Multifunctional Medical Recovery and Monitoring System for the Human Lower Limbs

Sensors ◽  
2019 ◽  
Vol 19 (22) ◽  
pp. 5042
Author(s):  
Adriana Comanescu ◽  
Ileana Dugaesescu ◽  
Doru Boblea ◽  
Liviu Ungureanu
Keyword(s):  
Monitoring System ◽  
Lower Limb ◽  
Lower Limbs ◽  
Relative Rotation ◽  
Monitoring Equipment ◽  
Medical Needs ◽  
Median Part ◽  
Rotation Motion ◽  
Human Limb ◽  
Angular Amplitude

In order to develop multifunctional medical recovery and monitoring equipment for the human lower limb, a new original mechanical structure with three degrees mobility has been created for the leg sagittal model. This mechanism is integrated in the equipment and includes elements that have similar functions to the different anatomic parts (femur, median part), leg, and foot. The independent relative rotation motion between the previously mentioned anatomic parts is ensured. The femur may have an oscillation rotation of about 100° relative to the trunk. The median part (leg) alternatively rotates 150° relative to the superior segment. The lower part (foot) is initially placed at 90° relative to the median part and may have an alternative rotation of 25°. Depending on a patient’s medical needs and their recovery progress, device sensors provide varying angular amplitude of different segments of the human limb. Moreover, the mechanism may actuate either anatomic leg segment, two parts, or all of them.

scholarly journals Differential cartilage turnover along the human lower limb revealed by protein deamidation

2018 ◽  
Vol 26 ◽  
pp. S32
Author(s):  
M.-F. Hsueh ◽  
P. Onnerfjord ◽  
M.P. Bolognesi ◽  
M.E. Easley ◽  
V.B. Kraus
Keyword(s):  
Lower Limb ◽  
Cartilage Turnover

scholarly journals Tissues and Cell Types of Appendage Regeneration: A Detailed Look at the Wound Epidermis and Its Specialized Forms

2021 ◽  
Vol 12 ◽  
Author(s):  
Can Aztekin
Keyword(s):  
Limb Regeneration ◽  
Cell Types ◽  
Tissue Level ◽  
Essential Component ◽  
New Information ◽  
Wound Epidermis ◽  
Human Limb ◽  
Wound Epithelium

Therapeutic implementation of human limb regeneration is a daring aim. Studying species that can regrow their lost appendages provides clues on how such a feat can be achieved in mammals. One of the unique features of regeneration-competent species lies in their ability to seal the amputation plane with a scar-free wound epithelium. Subsequently, this wound epithelium advances and becomes a specialized wound epidermis (WE) which is hypothesized to be the essential component of regenerative success. Recently, the WE and specialized WE terminologies have been used interchangeably. However, these tissues were historically separated, and contemporary limb regeneration studies have provided critical new information which allows us to distinguish them. Here, I will summarize tissue-level observations and recently identified cell types of WE and their specialized forms in different regeneration models.

scholarly journals Single-Cell RNA-Seq Reveals Novel Mitochondria-related Musculoskeletal Cell Populations during Adult Axolotl Limb Regeneration Process

2019 ◽  
Author(s):  
Tian Qin ◽  
Chun-mei Fan ◽  
Ting-zhang Wang ◽  
Long Yang ◽  
Wei-liang Shen ◽  
...  
Keyword(s):  
Single Cell ◽  
Large Scale ◽  
Limb Regeneration ◽  
Regenerative Process ◽  
Regeneration Process ◽  
The Novel ◽  
Cell Subpopulations ◽  
Cell Transcriptome ◽  
Human Limb ◽  
Single Cell Transcriptome

ABSTRACTWhile the capacity to regenerate tissues or limbs is limited in mammals including humans, unlike us, axolotls are able to regrow entire limbs and major organs. The wound blastema have been extensively studied in limb regeneration. However, due to the inadequate characterization and coordination of cell subpopulations involved in the regeneration process, it hinders the discovery of the key clue for human limb regeneration. In this study, we applied unbiased large-scale single-cell RNA sequencing to classify cells throughout the adult axolotl limb regeneration process. We computationally identified 7 clusters in regenerating limbs, including the novel regeneration-specific mitochondria-related cluster supporting regeneration through energy providing and the COL2+ cluster contributing to regeneration through cell-cell interactions signals. We also discovered the dedifferentiation and re-differentiation of the COL1+/COL2+ cellular subpopulation and uncovered a COL2-mitochondria sub-cluster supporting the musculoskeletal system regeneration. On the basis of these findings, we reconstructed the dynamic single-cell transcriptome atlas of adult axolotl limb regenerative process, and identified the novel regenerative mitochondria-related musculoskeletal populations, which yielded deeper insights into the crucial interactions between cell clusters within the regenerative microenvironment.

scholarly journals Common kinematic synergies of various human locomotor behaviours

2021 ◽  
Vol 8 (4) ◽  
Author(s):  
Bo Huang ◽  
Caihua Xiong ◽  
Wenbin Chen ◽  
Jiejunyi Liang ◽  
Bai-Yang Sun ◽  
...  
Keyword(s):  
Lower Limb ◽  
Mechanical Energy ◽  
Human Locomotion ◽  
Formation Mechanisms ◽  
Motor Ability ◽  
Joint Coordination ◽  
Standing Up ◽  
Potential Link ◽  
Kinematic Synergies ◽  
Joint Motions

Humans show a variety of locomotor behaviours in daily living, varying in locomotor modes and interaction styles with the external environment. However, how this excellent motor ability is formed, whether there are some invariants underlying various locomotor behaviours and simplifying their generation, and what factors contribute to the invariants remain unclear. Here, we find three common kinematic synergies that form the six joint motions of one lower limb during walking, running, hopping and sitting-down-standing-up (movement variance accounted for greater than 90%), through identifying the coordination characteristics of 36 lower limb motor tasks in diverse environments. This finding supports the notion that humans simplify the generation of various motor behaviours through re-using several basic motor modules, rather than developing entirely new modules for each behaviour. Moreover, a potential link is also found between these synergies and the unique biomechanical characteristics of the human musculoskeletal system (muscular-articular connective architecture and bone shape), and the patterns of inter-joint coordination are consistent with the energy-saving mechanism in locomotion by using biarticular muscles as efficient mechanical energy transducers between joints. Altogether, our work helps understand the formation mechanisms of human locomotion from a holistic viewpoint and evokes inspirations for the development of artificial limbs imitating human motor ability.

scholarly journals Can laboratory model systems instruct human limb regeneration?

Development ◽  
2019 ◽  
Vol 146 (20) ◽  
pp. dev181016 ◽  
Author(s):  
Ben D. Cox ◽  
Maximina H. Yun ◽  
Kenneth D. Poss
Keyword(s):  
Limb Regeneration ◽  
Model Systems ◽  
Laboratory Model ◽  
Human Limb

Condition of the soleus muscle center of the immobilized human limb

1982 ◽  
Vol 63 (2) ◽  
pp. 47-49
Author(s):  
I. N. Pleshchinsky ◽  
V. I. Alatyrev ◽  
S. A. Yunaleeva ◽  
L. G. Khasanova ◽  
M. S. Davydova ◽  
...  
Keyword(s):  
Electrical Activity ◽  
Soleus Muscle ◽  
Lower Limb ◽  
The State ◽  
H Reflex ◽  
Recurrent Inhibition ◽  
Intact Side ◽  
Reflex Excitability ◽  
Human Limb

The effect of immobilization of the lower limb on the state of the soleus muscle center and its electrical activity was studied. Using the H-reflex technique, a decrease in the reflex excitability of motoneurons and an increase in recurrent inhibition on the immobilization side compared to the intact side were established. A decrease in the amplitude of the M-response of the immobilized soleus muscle was also found.

Effect of acute food restriction on pulmonary growth and protein turnover in preterm guinea pigs

1992 ◽  
Vol 262 (2) ◽  
pp. E240-E245
Author(s):  
F. J. Kelly ◽  
J. C. Fussell ◽  
T. D. Postle
Keyword(s):  
Protein Synthesis ◽  
Protein Turnover ◽  
Guinea Pigs ◽  
Food Restriction ◽  
Chain Elongation ◽  
Free Access ◽  
Repair Capacity ◽  
Reduced Body ◽  
Immature Lung

The effects of food restriction on the growth and protein turnover of the immature lung were investigated. Preterm guinea pigs, delivered by cesarean section at 65 days gestation (term = 68 days), were given free access to a lactating dam or restricted from feeding for 48 h. Food restriction resulted in significantly reduced body and lung (P less than 0.05) weight compared with fed controls. The rate of pulmonary protein synthesis determined in vivo was reduced by 33% in the food-restricted pups (28.9 +/- 10.2 vs. 19.4 +/- 4.5%, P less than 0.05 for control and food-restricted pups, respectively), whereas the calculated rate of protein breakdown remained unchanged. The inhibition of protein synthesis was accounted for by a 36% decrease in ribosomal efficiency (11.03 +/- 2.61 vs. 7.04 +/- 1.26%, P less than 0.01 for control and food-restricted pups, respectively), whereas ribosomal capacity was unaltered. Polyribosomal analysis indicated an increase in the proportion of RNA present in polysomes and a fall in the free monomer pool (26%), suggesting that food restriction blocked translation by reducing the rate of peptide chain elongation. This finding was confirmed by the analysis of ribosome transit times, which indicated a significant increase in the elongation rate in the lungs from food-restricted pups (0.51 +/- 0.11 vs. 0.94 +/- 0.19 min, P less than 0.05 for control and food-restricted pups, respectively). These results imply that nutrient supply plays an important role in protein deposition and hence growth and repair capacity of the immature lung.

scholarly journals Effects of 2 weeks lower limb immobilization and two separate rehabilitation regimens on gastrocnemius muscle protein turnover signaling and normalization genes

2012 ◽  
Vol 5 (1) ◽  
Author(s):  
Anders Nedergaard ◽  
Jakob G Jespersen ◽  
Jessica Pingel ◽  
Britt Christensen ◽  
Nicholas Sroczynski ◽  
...  
Keyword(s):  
Lower Limb ◽  
Protein Turnover ◽  
Gastrocnemius Muscle ◽  
Muscle Protein ◽  
Muscle Protein Turnover ◽  
Limb Immobilization
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