scholarly journals Musculoskeletal Outcomes from Chronic High-Speed, High-Impulse Resistance Exercise

2018 ◽  
Vol 39 (10) ◽  
pp. 791-801 ◽  
Author(s):  
John Caruso ◽  
Michael Voor ◽  
Jason Jaggers ◽  
T. Symons ◽  
Jeremy Stith ◽  
...  
Keyword(s):  
Mechanical Loading ◽  
High Speed ◽  
Type I Collagen ◽  
Training Session ◽  
Knee Extension ◽  
Type I ◽  
Before And After ◽  
Force Peak ◽  
Blood Marker ◽  
Hip Extension

AbstractWhile bones and muscles adapt to mechanical loading, it appears that very specific types of stimuli must be applied to achieve osteogenesis. Our study assessed musculoskeletal outcomes to 30 training sessions on an Inertial Exercise Trainer (Newnan, GA). Subjects (n=13) performed workouts with their left leg, while their right served as an untreated control. Workouts entailed three 60-s sets each of knee extension, hip extension and calf press exercises, separated by 90-s rests. Before and after the 30 training sessions, subjects underwent strength tests (knee and ankle extensors of both legs), DEXA scans (hip, knee and ankles of both legs), and blood draws. After 30 training sessions 2×2 ANOVAs showed left leg peak torques rose significantly. 2×2 ANCOVAs, with bone scan area as a covariate, showed significant left leg calcaneal bone mineral content (+29%) and density (+33%) increases after 30 training sessions. A significant decline in C-terminal telopeptides of type I collagen, a blood marker of bone resorption, also occurred after 30 training sessions. The Inertial Exercise Trainer’s large volume of training session repetitions elicited high peak force, peak acceleration and impulses that likely provided a mechanical loading stimulus that evoked calcaneal accretion.

Platelet deposition on stainless steel, spiral, and braided polylactide stents

2004 ◽  
Vol 92 (12) ◽  
pp. 1394-1401 ◽  
Author(s):  
Paula Maasilta ◽  
Hanne Juuti ◽  
Juha-Pekka Nuutinen ◽  
Ari Harjula ◽  
Ulla-Stina Salminen ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Flow Rate ◽  
Type I Collagen ◽  
Blood Perfusion ◽  
Type I ◽  
Thrombotic Occlusion ◽  
Protein Deposition ◽  
Biodegradable Stents ◽  
Platelet Deposition ◽  
Before And After

SummaryPlatelets play a key role in (sub)acute thrombotic occlusion after stenting. We examined the possible differences between biodegradable polylactide (PLA) and stainless steel (SS) stents in platelet attachment and morphology after whole blood perfusion. PLA stents of different configurations (spiral/braided) and polycaprolactone-polylactide (PCL-PLA)-coatings, or SS stents were implanted into a PVC tube (Ø 3.2 mm), with or without precoating of the tube with type-I collagen. PPACK (30 µM)-anticoagulated blood with 3H-serotonin prelabeled platelets was perfused (flow rate: 30 ml/min, 90 s) over the stents. Platelet deposition was assessed by scintillation counting and morphology by scanning electron microscopy (SEM). To examine coagulation activation, plasma prothrombin fragments (F1+2) were measured before and after the perfusion. Protein deposition on PLA/SS stents was assessed at augmented shear forces mimicking coronary flow (rate: 60 ml/min, 60 s) under minimal anticoagulation (PPACK 1 µM). More platelets deposited on PLA stents than on SS stents under all study conditions (p <0.03). Under anticoagulation (PPACK 30 µM) the generation of F1+2 remained unaltered. Under higher flow rate and limited anticoagulation SS stents accumulated 3.27 ± 0.75 µg and PLA stents 5.25 ± 1.74 µg of protein (Mean ± SD, p <0.95). Among all biodegradable stents, the braided PLA stent coated with PCL-PLA-heparin accumulated the fewest platelets (p <0.02). In SEM, signs of platelet activation on braided heparin-coated PLA stents, when compared with uncoated braided PLA/SS stents, appeared modest. In conclusion, PCL-PLAheparin coating of biodegradable stents may enhance their hemocompatibility, expressed by less platelet deposition. Nevertheless, materials, design, and coating techniques of biodegradable stents must be further developed.

scholarly journals Response to Three Weeks of Sprint Interval Training Cannot Be Explained by the Exertional Level

Medicina ◽  
2020 ◽  
Vol 56 (8) ◽  
pp. 395
Author(s):  
Raulas Krusnauskas ◽  
Nerijus Eimantas ◽  
Neringa Baranauskiene ◽  
Tomas Venckunas ◽  
Audrius Snieckus ◽  
...  
Keyword(s):  
Average Power ◽  
Lactate Concentration ◽  
Training Session ◽  
Blood Lactate Concentration ◽  
Interval Training ◽  
Knee Extension ◽  
Peak Oxygen Uptake ◽  
Sprint Interval Training ◽  
Low Responders ◽  
Before And After

Background and Objectives: The all-out mode of sprint interval training (SIT) has been shown to be an efficient method for improving sports performance, exercise capacity, and aerobic fitness. Although the benefits of SIT are well described, the mechanisms underlying the different degrees of response remain largely unexplored. We aimed to assess the effects of exertion on the responsiveness to SIT. Materials and Methods: The participants were 28 young untrained men (mean ± SD age 25.7 ± 6.03 years) who exhibited either a large or small increase in Wingate test average power in response to nine SIT sessions performed over three weeks. Each training session comprised four–six bouts of 30 s all-out cycling interspaced with 4 min of rest. Individual responses were assessed using heart rate (HR) during exercise for all nine sessions, as well as blood lactate concentration up to 1 h, and the decrement in maximal voluntary knee extension torque (MVC) up to 24 h after the first and last training sessions. Peak oxygen uptake (VO2peak) and maximum HR were measured before and after training during an incremental cycling test to exhaustion. Results: Although all participants showed benefits of SIT such as increased VO2peak, the increase in anaerobic cycling power varied between participants. We identified 17 high responders and nine low responders, whose average power outputs were 0.80 ± 0.22 and 0.22 ± 0.19 W/kg, respectively. The HR achieved during any of the training sessions did not differ between high and low responders. The lactate kinetics did not differ between groups before and after the intervention. Training resulted in a more rapid recovery of MVC without any discernible differences between the high and low responders. Conclusion: The differences in the responses to SIT are not dependent on the exertion level during training.

scholarly journals A Type I Collagen-Targeted MR Imaging Probe for Staging Fibrosis in Crohn’s Disease

2021 ◽  
Vol 8 ◽  
Author(s):  
Zhoulei Li ◽  
Baolan Lu ◽  
Jinjiang Lin ◽  
Shaofu He ◽  
Li Huang ◽  
...  
Keyword(s):  
Crohn’S Disease ◽  
Crohn's Disease ◽  
Mr Imaging ◽  
Rat Model ◽  
Type I Collagen ◽  
Type I ◽  
Imaging Probe ◽  
Antifibrotic Therapy ◽  
Before And After ◽  
Targeted Mri

Fibrostenosis is a serious complication of Crohn’s disease (CD), affecting approximately one-half of all patients. Surgical resection is the typical clinical end due to ineffective antifibrotic therapy mainly through anti-inflammatory treatment and fibrosis can be reverted only at early stages. Mover, human fibrotic disorders is known to be associated with aging process. Thus, accurate monitoring of the progression of fibrosis is crucial for CD management as well as can be benefit to aging related fibrosis. The excessive deposition of type I collagen (ColI) is the core point in major complications of fibrosis, including that in patients with CD and aging related fibrosis. Therefore, a MR imaging probe (EP-3533) targeted ColI was employed to stage bowel fibrosis in CD using a rat model and to compare its efficiency with the common MR imaging contrast medium gadopentetatedimeglumine (Gd-DTPA). The bowel fibrotic rat model was established with different degrees of bowel fibrosis, were scanned using a 3.0-T MRI scanner with a specialized animal coil. MRI sequence including T1 mapping and T1-weighed imaging were performed before and after injecting the MRI probe (EP-3533 or Gd-DTPA). The T1 relaxation time (T1 value) and change in the contrast-to-noise ratio (ΔCNR) were measured to evaluate bowel fibrosis. Masson’s trichrome staining was performed to determine the severity of fibrosis. EP-3533 offered a better longitudinal relaxivity (r1) with 67.537 L/mmol·s, which was approximately 13 times that of Gd-DTPA. The T1 value on bowel segments was reduced in the images from EP-3533 compared to that from Gd-DTPA (F = 16.478; p &lt; 0.001). Additionally, a better correlation between ΔCNR calculated from EP-3533 imaging and bowel fibrosis (AUC = 0.846) was determined 10 min after enhanced media administration than with Gd-DTPA (AUC = 0.532). The 10th-minute ΔCNR performed using the ColI probe showed the best correlation with the severity of bowel fibrosis (r = 0.538; p = 0.021). Our results demonstrates that targeted MRI probe (EP-3533) supplies a better enhanced effect compared to Gd-DTPA and could be a promising method to evaluate the progression and monitor the therapeutic response of bowel fibrosis.

scholarly journals Effects of the Non-Face-To-Face Learning on Health-Related Physical Fitness and Balance in Adolescents According to COVID-19

2021 ◽  
Vol 30 (2) ◽  
pp. 229-236
Author(s):  
Kwang-Jin Lee ◽  
Kyong-Won Seo ◽  
Keun-Ok An
Keyword(s):  
Muscle Strength ◽  
Physical Fitness ◽  
Knee Extension ◽  
Female Group ◽  
Balance Test ◽  
Face To Face ◽  
Before And After ◽  
Health Related ◽  
Face To Face Learning ◽  
Hip Extension

PURPOSE:This study aimed to examine the effects of non-face-to-face learning on health-related physical fitness and balance in adolescents according to the coronavirus disease 2019 (COVID-19).METHODS:Twenty-nine middle-school students (14 girls and 15 boys) were enrolled. We measured the students’ health-related physical fitness (body composition, muscle strength, muscle endurance, flexibility, and cardiac endurance) and balance (static and dynamic) before and after 12 weeks of non-face-to-face learning without any exercise intervention. Cardiac endurance was measured using the Harvard step test.RESULTS: Body fat, muscle strength (hip flexion, hip extension, knee flexion, knee extension), and Y-balance test exhibited significant differences before and after non-face-to-face learning (<i>p</i><.05). Body fat, muscle strength (hip flexion, hip extension), and Y-Balance test exhibited significant differences in the female group (<i>p</i><.05). Hip extension muscle strength exhibited a significant difference in the male group (<i>p</i><.05). Analysis of covariance showed that muscle strength (hip extension and knee extension) and Harvard step of the female group were significantly decreased compared to the male group (<i>p</i><.05).CONCLUSIONS: Non-face-to-face classes according to COVID-19 had a negative effect on health-related physical fitness and balance in adolescents. Particularly, the muscle strength and cardiac endurance of female adolescents were lower than those of male adolescents.

scholarly journals T Cell Migration in Three-dimensional Extracellular Matrix: Guidance by Polarity and Sensations

2000 ◽  
Vol 7 (2-4) ◽  
pp. 249-266 ◽  
Author(s):  
Peter Friedl ◽  
Eva-Bettina Bröker
Keyword(s):  
Extracellular Matrix ◽  
Cell Migration ◽  
T Cell ◽  
High Speed ◽  
Type I Collagen ◽  
Shape Change ◽  
Type I ◽  
Cell Trafficking ◽  
T Cell Migration ◽  
Migration Strategies

The locomotion of T lymphocytes within 3-D extracellular matrix (ECM) is a highly dynamic and flexible process following the principles of ameboid movement. Ameboid motility is characterized by a polarized yet simple cell shape allowing high speed, rapid directional oscillations, and low affinity interactions to the substrate that are coupled to a low degree of cytoskeletal organization lacking discrete focal contacts. At the onset of T cell migration, a default program, here described as migration-associated polarization, is initiated, resulting in the polar redistribution of cell surface receptors and cytoskeletal elements. Polarization involves protein cycling either to the leading edge (i.e. LFA-1, CD45RO, chemokine receptors, focal adhesion kinase), to a central polarizing compartment (MTOC, PKC, MARCKS), or into the uropod (CD44, CD43, ICAM- and –3, β1 integrins). The function of such compartment formation may be important in chemotactic response, scanning of encountered cells, and a flexible and adaptive interaction with the ECM itself. Due to the simple shape and a diffusely organized cytoskeleton, the interactions to the surrounding extracellular matrix are rapid and reversible and appear to allow a broad spectrum of molecular migration strategies. These range from (1) adhesive and haptokinetic following i.e. chemokine-induced motility across 2-D surfaces to (2) largely integrin-independent migration predominantly guided by shape change and morphological flexibility, as seen in 3-D type I collagen matrices. Their prominent capacity to rapidly adapt to a given structural environment coupled to contact guidance mechanisms set T cell locomotion apart from slow, focal contact-dependent and more adhesive migration strategies established by fibroblast-like cells and cell clusters. It is therefore likely that, within the tissues, besides chemotactic or haptotactic gradients, the preformed matrix structure has an important impact on T cell trafficking and positioning in health and disease.

scholarly journals Preparative Purification of Bioactive Compounds fromFlos Chrysanthemi Indiciand Evaluation of Its Antiosteoporosis Effect

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Jia Li ◽  
Xiaosheng Lin ◽  
Yuping Zhang ◽  
Weicai Liu ◽  
Xiaohui Mi ◽  
...  
Keyword(s):  
Bioactive Compounds ◽  
High Speed ◽  
Type I Collagen ◽  
Ethanol Extract ◽  
Ethyl Acetate Fraction ◽  
Gradient Elution ◽  
Type I ◽  
Mrna Levels

To understand the material basis and underlying molecular machinery of antiosteoporosis activity of theFlos Chrysanthemi Indici(FCI), the consequences of ethanol extract on the bone loss in mice induced due to ovariectomy (OVX) was evaluated. Also, the antiosteoporosis fraction obtained from the FCI ethanol extract was isolated and purified using a preparative high-speed countercurrent chromatography (HSCCC). Thein vitroimpact of the compounds was investigated on osteoblast proliferation and differentiation. The results revealed that ethyl acetate fraction with robustin vivoantiosteoporosis activity was obtained. The important compounds purified by HSCCC using gradient elution system included acacetin, apigenin, luteolin, and linarin. The four compounds enhanced the differentiation and proliferation of osteoblasts in MC3T3-E1 cells. They also augmented the mRNA levels of runt-related transcription factor 2 (Runx2), osteocalcin (OCN), osteopontin (OPN), and type I collagen (COL I). The AKT signaling pathway was also activated in MC3T3-E1 cells by the four compounds. The present study demonstrated that the antiosteoporosis effects of FCI did not depend on a single component, and HSCCC efficiently isolated and purified the antiosteoporosis bioactive compounds from FCI.

scholarly journals Synergist ablation induces rapid tendon growth through the synthesis of a neotendon matrix

2014 ◽  
Vol 117 (11) ◽  
pp. 1287-1291 ◽  
Author(s):  
Jonathan P. Gumucio ◽  
Anthony C. Phan ◽  
David G. Ruehlmann ◽  
Andrew C. Noah ◽  
Christopher L. Mendias
Keyword(s):  
Mechanical Loading ◽  
Type I Collagen ◽  
Fluorescent Microscopy ◽  
Type I ◽  
Fibroblast Cells ◽  
Cellular Mechanisms ◽  
Fast Green ◽  
Cross Sectional ◽  
Plantaris Tendon ◽  
Insight Into

Mechanical loading can increase tendon cross-sectional area (CSA), but the mechanisms by which this occurs are largely unknown. To gain a greater understanding of the cellular mechanisms of adult tendon growth in response to mechanical loading, we used a synergist ablation model whereby a tenectomy of the Achilles tendon was performed to induce growth of the synergist plantaris tendon. We hypothesized that after synergist ablation progenitor cells in the epitenon would proliferate and increase the size of the existing tendon matrix. Adult male mice were subjected to a bilateral Achilles tenectomy, and plantaris tendons were isolated from mice at 0, 2, 7, 14, and 28 days after surgery. Tendons were sectioned stained with either fast green and hematoxylin, prepared for fluorescent microscopy, or prepared for gene expression of scleraxis and type I collagen. After overload, there was a dramatic increase in total CSA of tendons, whereas the size of the original tendon matrix was not changed. Growth primarily occurred through the formation of a neotendon matrix between the original tendon and the epitenon, and contained cells that were proliferative and scleraxis positive. Additionally, an initial expansion of fibroblast cells occurred before the synthesis of new extracellular matrix. Fibroblasts in the original tendon did not re-enter the cell cycle. The results from this study provide new insight into the mechanisms of tendon growth, indicate tendon consists mostly of postmitotic cells, and that growth of tendon primarily occurs from the most superficial layers outward.

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