Effects of long-term exercise on the biomechanical properties of the Achilles tendon of guinea fowl

2001 ◽  
Vol 90 (1) ◽  
pp. 164-171 ◽  
Author(s):  
Cindy I. Buchanan ◽  
Richard L. Marsh
Keyword(s):  
Biomechanical Properties ◽  
Guinea Fowl ◽  
Cross Sectional ◽  
Tendon Stiffness ◽  
Mechanical Fatigue ◽  
Downhill Running ◽  
Numida Meleagris ◽  
Tendon Compliance

The purpose of this study was to determine the effect of long-term exercise on tendon compliance and to ascertain whether tendons adapt differently to downhill running vs. running on a level surface. We carried out this investigation on the gastrocnemius tendon of helmeted guinea fowl ( Numida meleagris) that were trained for 8–12 wk before commencing experimental procedures. We used an in situ technique to measure tendon stiffness. The animals were deeply anesthetized with isofluorane during all in situ procedures. Our results indicate that long-term exercise increased tendon stiffness. This finding held true after normalization for the cross-sectional area of the free tendon, likely reflecting a change in the material properties of the exercised tendons. Whether training consisted of level or downhill running did not appear to influence response of the tendon to exercise. We hypothesize that the increased stiffness observed in tendons after a long-term running program may be a response to repeated stress and may function as a mechanism to resist tendon damage due to mechanical fatigue.

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

2013 ◽  
Vol 114 (8) ◽  
pp. 998-1008 ◽  
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.

Evaluation of permeable reactive barrier (PRB) integrity using electrical imaging methods

Geophysics ◽  
2003 ◽  
Vol 68 (3) ◽  
pp. 911-921 ◽  
Author(s):  
Lee Slater ◽  
Andrew Binley
Keyword(s):  
Geophysical Methods ◽  
Permeable Reactive Barrier ◽  
Electrical Measurements ◽  
Cross Sectional ◽  
Imaging Methods ◽  
Reactive Barrier ◽  
Electrical Imaging ◽  
Granular Iron

The permeable reactive barrier (PRB) is a promising in‐situ technology for treatment of hydrocarbon‐contaminated groundwater. A PRB is typically composed of granular iron which degrades chlorinated organics into potentially nontoxic dehalogenated organic compounds and inorganic chloride. Geophysical methods may assist assessment of in‐situ barrier integrity and evaluation of long‐term barrier performance. The highly conductive granular iron makes the PRB an excellent target for conductivity imaging methods. In addition, electrochemical storage of charge at the iron–solution interface generates an impedance that decreases with frequency. The PRB is thus a potential induced polarization (IP) target. Surface and cross‐borehole electrical imaging (conductivity and IP) was conducted at a PRB installed at the U.S. Department of Energy's Kansas City plant. Poor signal strength (25% of measurements exceeding 8% reciprocal error) and insensitivity at depth, which results from current channeling in the highly conductive iron, limited surface imaging. Crosshole 2D and 3D electrical measurements were highly effective at defining an accurate, approximately 0.3‐m resolution, cross‐sectional image of the barrier in‐situ. Both the conductivity and IP images reveal the barrier geometry. Crosshole images obtained for seven panels along the barrier suggest variability in iron emplacement along the installation. On five panels the PRB structure is imaged as a conductive feature exceeding 1 S/m. However, on two panels the conductivity in the assumed vicinity of the PRB is less than 1 S/m. The images also suggest variability in the integrity of the contact between the PRB and bedrock. This noninvasive, in‐situ evaluation of barrier geometry using conductivity/IP has broad implications for the long‐term monitoring of PRB performance as a method of hydrocarbon removal.

scholarly journals Short Term Versus Long Term Catheterization after Urogenital Prolapse Surgery

2012 ◽  
Vol 3 (2) ◽  
pp. 41-43
Author(s):  
Farzana Rabee Choudhury ◽  
Maliha Rashid ◽  
Ratu Rumana ◽  
ABM Zakir Uddin ◽  
Nilufar Nasrin Ava
Keyword(s):  
Genital Prolapse ◽  
Cross Sectional Study ◽  
Prolapse Surgery ◽  
Case Group ◽  
Short Term ◽  
Cross Sectional ◽  
Medical College ◽  
Better Than

Background: Genital prolapse is a common gynaecological problem in developing country like Bangladesh.Objectives: The aim of this study was to evaluate the advantages of short term catheterization in comparison to long term catheterization after genital prolapse surgery. Methodology: This was a prospective analytical cross sectional study being carried out from 1st July 2005 to 30th July 2006 in the Department of Gynaecology & Obstetrics of Sir Salimullah Medical College & Mitford Hospital. A total of 200 patients undergoing genital prolapse surgery were selected for this study. Patients were divided into two groups. In short term catheterization group the urinary catheter was withdrawal within one day after surgery and in the short term catheterization group the catheter was remained in situ for 5 days after surgery. Result: Positive urine culture was found in 16% in long term catheterization group compared with 6% in short term group (P=0.02). Mean duration of hospital stay was 6.98 days in long term catheterization group and 4.68 days in short term catheterization group (P<0.01). Residual volume was more than 200 ml and need for re-catheterization occurred in 3% in group whereas it was 10% in case group (P=0.04). Conclusion: This study permits to conclude that short term catheterization is better than long term catheterization. J Shaheed Suhrawardy Med Coll, 2011;3 (2): 41-43 DOI: http://dx.doi.org/10.3329/jssmc.v3i2.12077

Effects of Bisphosphonate on Long-Term Culture of Cartilage Allografts

2013 ◽  
Author(s):  
Yilu Zhou ◽  
Lauren Resutek ◽  
Liyun Wang ◽  
X. Lucas Lu
Keyword(s):  
Medial Meniscus ◽  
Biomechanical Properties ◽  
Culture Conditions ◽  
Protective Mechanisms ◽  
Post Traumatic ◽  
Biochemical Mechanisms ◽  
Altered Metabolism

Zoledronic acid (ZA), an FDA approved bisphosphonate (BP) medicine, is widely used for the treatment of osteoclast-related bone loss diseases [1]. Our previous study has found that systemic administration of ZA could dramatically suppress the development of post-traumatic osteoarthritis (PTOA) in the DMM (destabilization of the medial meniscus) mouse model, a model recapitulating the altered joint loading associated with PTOA [2]. This finding is consistent with a few similar studies using different animal models [3]. However, little is known about the cellular and biochemical mechanisms of BP mediated chondro-protection in PTOA pathogenesis. Studies have shown that PTOA often initiates from the apoptosis and altered metabolism of cartilage chondrocytes. In this study, we will investigate the direct effects of ZA on the metabolisms of chondrocytes using long-term in vitro culture of cartilage allografts. As one of the earliest responses of chondrocytes to mechanical stimulation, intracellular calcium ([Ca 2+] i) signaling is the upstream of numerous mechanotransduction pathways [4]. We hypothesize that the chondro-protective mechanisms of ZA could be represented by the characteristics of [Ca 2+] i signaling of in situ chondrocytes. Our specific aims were to: (i) compare the in situ spontaneous [Ca 2+] i responses of chondrocytes cultured in non-ZA and ZA supplemented environments, and (ii) compare the biomechanical properties of cartilage allografts under the two culture conditions.

scholarly journals Long-term bisphosphonate treatment coupled with ovariectomy in mice provokes deleterious effects on femoral neck fracture pattern and modifies tibial shape

2020 ◽  
Vol 1 (9) ◽  
pp. 512-519
Author(s):  
Samuel Monzem ◽  
Rafael Y. Ballester ◽  
Behzad Javaheri ◽  
Blandine Poulet ◽  
Dábila A. Sônego ◽  
...  
Keyword(s):  
Femoral Neck ◽  
Biomechanical Properties ◽  
Fracture Pattern ◽  
Bisphosphonate Treatment ◽  
Atypical Fracture ◽  
Cross Sectional ◽  
Yield Displacement ◽  
Neck Fracture ◽  
Old Mice

Aims The processes linking long-term bisphosphonate treatment to atypical fracture remain elusive. To establish a means of exploring this link, we have examined how long-term bisphosphonate treatment with prior ovariectomy modifies femur fracture behaviour and tibia mass and shape in murine bones. Methods Three groups (seven per group) of 12-week-old mice were: 1) ovariectomized and 20 weeks thereafter treated weekly for 24 weeks with 100 μm/kg subcutaneous ibandronate (OVX+IBN); 2) ovariectomized (OVX); or 3) sham-operated (SHAM). Quantitative fracture analysis generated biomechanical properties for the femoral neck. Tibiae were microCT scanned and trabecular (proximal metaphysis) and cortical parameters along almost its whole length measured. Results Fracture analyses revealed that OVX+IBN significantly reduced yield displacement (vs SHAM/OVX) and resilience, and increased stiffness (vs SHAM). OVX+IBN elevated tibial trabecular parameters and also increased cortical cross-sectional area and second moment of area around minor axis, and diminished ellipticity proximally. Conclusion These data indicate that combined ovariectomy and bisphosphonate generates cortical changes linked with greater bone brittleness and modified fracture characteristics, which may provide a basis in mice for interrogating the mechanisms and genetics of atypical fracture aetiology. Cite this article: Bone Joint Open 2020;1-9:512–519.

In Situ Calcium Signaling of Chondrocytes Under Non-Serum and Serum Culture

2013 ◽  
Author(s):  
Yilu Zhou ◽  
Lauren Resutek ◽  
Liyun Wang ◽  
X. Lucas Lu
Keyword(s):  
Calcium Signaling ◽  
Mechanical Stimulation ◽  
Biomechanical Properties ◽  
Cellular Level ◽  
Cartilage Explants ◽  
Serum Free ◽  
Better Than

Chemically defined serum-free medium has been shown to maintain the mechanical properties of cartilage allografts better than serum supplemented medium during long-term in vitro culture [1]. Little is known about this beneficial mechanism at a cellular level. Intracellular calcium ([Ca2+]i) signaling is one of the earliest responses in chondrocytes under mechanical stimulation [2]. It was recently found that calcium signaling is involved in the regulation of chondrocyte morphology changes and its short-term anabolic and catabolic responses under mechanical stimulation [3]. In this study we hypothesized that the beneficial mechanisms of serum-free culture could be indicated by the spatiotemporal features of [Ca2+]i signaling of chondrocytes in situ. We aimed to: (i) compare the in situ spontaneous [Ca2+]i responses of chondrocytes cultured in medium with and without serum; (ii) investigate the correlation between the [Ca2+]i responses of chondrocytes and the biomechanical properties of cartilage explants.

Effect of growth hormone on aging connective tissue in muscle and tendon: gene expression, morphology, and function following immobilization and rehabilitation

2014 ◽  
Vol 116 (2) ◽  
pp. 192-203 ◽  
Author(s):  
A. P. Boesen ◽  
K. Dideriksen ◽  
C. Couppé ◽  
S. P. Magnusson ◽  
P. Schjerling ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Mrna Expression ◽  
Biomechanical Properties ◽  
Gene Expressions ◽  
Cross Sectional ◽  
Tendon Stiffness ◽  
Transmission Electron ◽  
Fibril Morphology ◽  
And Function ◽  
Elderly Humans

It is unknown whether loss in musculotendinous tissue during inactivity can be counteracted by growth hormone (GH), and whether GH accelerate rehabilitation in aging individuals. Elderly men (65–75 yr; n = 12) had one leg immobilized 2 wk followed by 6 wk of retraining and were randomly assigned to daily injections of recombinant GH (rhGH; n = 6) or placebo (Plc; n = 6). Cross-sectional area (CSA), muscle strength (MVC), and biomechanical properties of m. quadriceps and patellar tendon were determined. Muscle and tendon biopsies were analyzed for gene expressions (mRNA) of collagen (COL1A1/3A1) and insulin-like growth factors (IGF-1Ea/Ec). Fibril morphology was analyzed by transmission electron microscope (TEM). In tendon, CSA and biomechanical properties did not change following immobilization, but an increase in CSA was found after 6 wk of rehabilitation in both groups. The changes were more pronounced when GH was injected. Furthermore, tendon stiffness increased in the GH group. Muscle CSA declined after immobilization in the Plc but not in the GH group. Muscle CSA increased during retraining, with a significantly larger increase in the GH group compared with the Plc group. Both a time and a group effect were seen for IGF-1Ea/Ec and COL1A1/3A1 mRNA expression in muscle, with a difference between GH and Plc. IGF-1Ea/Ec and COL-1A1/3A1 mRNA expression increased in muscle following immobilization and retraining in subjects receiving GH, whereas an increase in IGF-1Ec mRNA expression was seen in the Plc group only after retraining. In conclusion, in elderly humans, GH seems to have a matrix stabilizing effect during inactivity and rehabilitation by stimulating collagen expression in the musculotendinous tissue and increasing tendon CSA and stiffness.

The reaction of amorphous Ni-Nb films with Si in the presence of a native SiO2 layer

1990 ◽  
Vol 48 (4) ◽  
pp. 664-665
Author(s):  
N. Rozhanski ◽  
A. Barg
Keyword(s):  
High Temperature ◽  
Crystallization Temperature ◽  
Diffusion Barriers ◽  
Sio2 Layer ◽  
Si Substrate ◽  
Cross Sectional ◽  
Plan View ◽  
Temperature Range ◽  
Sputter Deposited

Amorphous Ni-Nb alloys are of potential interest as diffusion barriers for high temperature metallization for VLSI. In the present work amorphous Ni-Nb films were sputter deposited on Si(100) and their interaction with a substrate was studied in the temperature range (200-700)°C. The crystallization of films was observed on the plan-view specimens heated in-situ in Philips-400ST microscope. Cross-sectional objects were prepared to study the structure of interfaces.The crystallization temperature of Ni5 0 Ni5 0 and Ni8 0 Nb2 0 films was found to be equal to 675°C and 525°C correspondingly. The crystallization of Ni5 0 Ni5 0 films is followed by the formation of Ni6Nb7 and Ni3Nb nucleus. Ni8 0Nb2 0 films crystallise with the formation of Ni and Ni3Nb crystals. No interaction of both films with Si substrate was observed on plan-view specimens up to 700°C, that is due to the barrier action of the native SiO2 layer.

Theoretical and Methodological Problems of a 10-Year Follow-Up Program Evaluation Study

2002 ◽  
Vol 18 (3) ◽  
pp. 229-241 ◽  
Author(s):  
Kurt A. Heller ◽  
Ralph Reimann
Keyword(s):  
Program Evaluation ◽  
Evaluation Studies ◽  
Evaluation Study ◽  
Control Groups ◽  
Cross Sectional ◽  
Long Term Study ◽  
Partial Inclusion ◽  
Methodological Problems

Summary In this paper, conceptual and methodological problems of school program evaluation are discussed. The data were collected in conjunction with a 10 year cross-sectional/longitudinal investigation with partial inclusion of control groups. The experiences and conclusions resulting from this long-term study are revealing not only from the vantage point of the scientific evaluation of new scholastic models, but are also valuable for program evaluation studies in general, particularly in the field of gifted education.

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