Subchondral Bone Mineral Density Patterns Representing the Loading History of the Wrist Joint

2002 ◽  
Vol 27 (2) ◽  
pp. 150-154 ◽  
Author(s):  
M. M. HOOGBERGEN ◽  
W. J. NIESSEN ◽  
A. H. SCHUURMAN ◽  
P. H. M. SPAUWEN ◽  
J. M. G. KAUER
Keyword(s):  
Bone Density ◽  
Subchondral Bone ◽  
Wrist Joint ◽  
Force Transmission ◽  
Mineral Density ◽  
Distal Ulna ◽  
Before And After ◽  
History Of ◽  
Lunate Fossa

Ten cadaver wrists were examined with CT-Absorptiometry in order to assess bone density in the subchondral bone. In normal wrists the distal radius contained two centroids of bone density, one in the lunate fossa and another in the scaphoid fossa. Pathologically altered wrists showed a shift in bone density towards the scaphoid fossa, with the subchondral bone in the lunate fossa and distal ulna becoming less dense. Bone density patterns in the wrist reflect the long-term force transmission. As bone density alters according to loading conditions, this method can be used to determine force transmission patterns before and after wrist surgery.

Subchondral bone mineral density patterns representing the loading history of the wrist joint after a proximal row carpectomy

2008 ◽  
Vol 31 (3) ◽  
pp. 101-107
Author(s):  
J. M. P. Schots ◽  
W. J. Niessen ◽  
A. H. Schuurman ◽  
P. H. M. Spauwen ◽  
J. M. G. Kauer ◽  
...  
Keyword(s):  
Bone Mineral Density ◽  
Bone Mineral ◽  
Subchondral Bone ◽  
Wrist Joint ◽  
Loading History ◽  
Proximal Row Carpectomy ◽  
Mineral Density ◽  
History Of

scholarly journals Fine-tuning citrate synthase flux potentiates and refines metabolic innovation in the Lenski evolution experiment

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Erik M Quandt ◽  
Jimmy Gollihar ◽  
Zachary D Blount ◽  
Andrew D Ellington ◽  
George Georgiou ◽  
...  
Keyword(s):  
Citrate Synthase ◽  
Fine Tuning ◽  
Ecological Niches ◽  
Glta Gene ◽  
Evolutionary Changes ◽  
Before And After ◽  
Evolution Experiment ◽  
History Of ◽  
Second Wave

Evolutionary innovations that enable organisms to colonize new ecological niches are rare compared to gradual evolutionary changes in existing traits. We discovered that key mutations in the gltA gene, which encodes citrate synthase (CS), occurred both before and after Escherichia coli gained the ability to grow aerobically on citrate (Cit+ phenotype) during the Lenski long-term evolution experiment. The first gltA mutation, which increases CS activity by disrupting NADH-inhibition of this enzyme, is beneficial for growth on the acetate and contributed to preserving the rudimentary Cit+ trait from extinction when it first evolved. However, after Cit+ was refined by further mutations, this potentiating gltA mutation became deleterious to fitness. A second wave of beneficial gltA mutations then evolved that reduced CS activity to below the ancestral level. Thus, dynamic reorganization of central metabolism made colonizing this new nutrient niche contingent on both co-opting and overcoming a history of prior adaptation.

scholarly journals Serum 25(OH)D3 vitamin status of elderly Finnish women is suboptimal even after summer sunshine but is not associated with bone density or turnover

2010 ◽  
Vol 162 (1) ◽  
pp. 183-189 ◽  
Author(s):  
Tuula Pekkarinen ◽  
Ursula Turpeinen ◽  
Esa Hämäläinen ◽  
Eliisa Löyttyniemi ◽  
Henrik Alfthan ◽  
...  
Keyword(s):  
Vitamin D ◽  
Bone Density ◽  
Bone Turnover ◽  
Population Based ◽  
Type I ◽  
Vitamin D Status ◽  
Mineral Density ◽  
Type I Procollagen ◽  
Before And After ◽  
Before And After Summer

ObjectiveConcentrations of 50 and 75 nmol/l are proposed as serum 25-hydroxyvitamin D (25(OH)D) target for older people from the view of bone health. We evaluated vitamin D status of elderly Finnish women in light of these definitions, its relationship to bone mineral density (BMD) and turnover, and improvement by summer sunshine.DesignPopulation-based study.MethodsA total of 1604 ambulatory women aged 62–79 years were studied; 66% used vitamin D supplements. Serum 25(OH)D3was measured with HPLC before and after summer, and heel BMD in spring. In subgroups, serum parathyroid hormone (PTH) and type I procollagen aminoterminal propeptide (PINP) were analyzed.ResultsIn spring, 60.3% of the women had 25(OH)D3≤50 nmol/l, and the target of 75 nmol/l was reached by 9.1%. For supplement users, the respective numbers were 52.1 and 11.9%. Serum 25(OH)D3did not determine BMD or bone turnover measured by serum PINP. Summer sunshine increased serum 25(OH)D3by 17.4% (P<0.0001), but in autumn 84% of the subjects remained under the target of 75 nmol/l. In supplement users, PTH remained stable but decreased in others during summer (P=0.025).ConclusionsVitamin D status of elderly Finnish women is suboptimal if 25(OH)D3levels of 50 or 75 nmol/l are used as a threshold. It is moderately increased by supplement intake and summer sunshine. However, 25(OH)D3concentrations did not influence bone density in terms of serum PINP and bone turnover rate.

Long-term effects of tibial plateau leveling osteotomy and tibial tuberosity advancement on tibial plateau subchondral bone density in dogs

2018 ◽  
Vol 47 (4) ◽  
pp. 566-571 ◽  
Author(s):  
Elizabeth S. Leach ◽  
Ursula Krotscheck ◽  
Kelsey J. Goode ◽  
Galina M. Hayes ◽  
Peter Böttcher
Keyword(s):  
Bone Density ◽  
Subchondral Bone ◽  
Tibial Plateau ◽  
Tibial Tuberosity ◽  
Long Term Effects ◽  
Subchondral Bone Density

scholarly journals Spatial Subchondral Bone Density Reflecting Joint Loading of the Talus in Different Canidae

2019 ◽  
Vol 32 (03) ◽  
pp. 207-214
Author(s):  
Walter Dingemanse ◽  
Ingrid Gielen ◽  
Henri van Bree ◽  
Magdalena Müller-Gerbl ◽  
Nikola Krstić ◽  
...  
Keyword(s):  
Bone Density ◽  
Density Distribution ◽  
Subchondral Bone ◽  
Canis Lupus ◽  
Joint Loading ◽  
German Shepherd ◽  
Canis Aureus ◽  
Joint Biomechanics ◽  
Subchondral Bone Density

Objective Subchondral bone density distribution can be used to study joint biomechanics non-invasively. Differences in joint loading between related species can aid in the understanding of joint loading and the development of certain types of orthopaedic pathology. This study was conducted to evaluate density distribution in the subchondral bone of the talus of different Canidae species, as a parameter reflecting the long-term joint loading in the tarsocrural joint. Materials and Methods The tarsal joints of cadaveric dogs of different breeds were included, that is, German Shepherd (n = 5), Bouvier des Flandres (n = 3) and Labrador Retriever (n = 6).Additionally, golden jackals (n = 5) (Canis aureus) and wolves (n = 5) (Canis lupus) were included. Consecutive computed tomography slices were made and the subchondral bone density distribution was evaluated using computer tomographic osteoabsorptiometry. Different breeds and species were visually compared. Results Differences were found in the subchondral bone density distribution of the talus between breeds and between species (Canis familiaris, Canis lupus and Canis aureus). Discussion and Conclusion Based on the density distribution, there are differences in loading conditions of the tarsocrural joint in different species of Canidae. The joint loading distribution is very similar between dogs of the same breed and within the same species. Although between-breed differences can be explained by conformational differences, the between-species differences remain subject to further research.

Priming-Induced Shift in Synaptic Plasticity in the Rat Hippocampus

1999 ◽  
Vol 82 (4) ◽  
pp. 2024-2028 ◽  
Author(s):  
Hongyan Wang ◽  
John J. Wagner
Keyword(s):  
Synaptic Plasticity ◽  
Hippocampal Slices ◽  
Long Term Potentiation ◽  
Crossover Point ◽  
Term Potentiation ◽  
Before And After ◽  
History Of ◽  
The Brain ◽  
Dependent Mechanism

The activity history of a given neuron has been suggested to influence its future responses to synaptic input in one prominent model of experience-dependent synaptic plasticity proposed by Bienenstock, Cooper, and Munro (BCM theory). Because plasticity of synaptic plasticity (i.e., metaplasticity) is similar in concept to aspects of the BCM proposal, we have tested the possibility that a form of metaplasticity induced by a priming stimulation protocol might exhibit BCM-like characteristics. CA1 field excitatory postsynaptic potentials (EPSPs) obtained from rat hippocampal slices were used to monitor synaptic responses before and after conditioning stimuli (3–100 Hz) of the Schaffer collateral inputs. A substantial rightward shift (>5-fold) in the frequency threshold between long-term depression (LTD) and long-term potentiation (LTP) was observed <1 h after priming. This change in the LTD/P crossover point occurred at both primed and unprimed synaptic pathways. These results provide new support for the existence of a rapid, heterosynaptic, experience-dependent mechanism that is capable of modifying the synaptic plasticity phenomena that are commonly proposed to be important for developmental and learning/memory processes in the brain.

scholarly journals Long-term Stress Distribution Patterns Across the Ankle Joint in Soccer Players: A Computed Tomography Osteoabsorptiometry Study

2020 ◽  
Vol 8 (11) ◽  
pp. 232596712096308
Author(s):  
Junki Shiota ◽  
Daisuke Momma ◽  
Takayoshi Yamaguchi ◽  
Norimasa Iwasaki
Keyword(s):  
Bone Density ◽  
Stress Distribution ◽  
Ankle Joint ◽  
Subchondral Bone ◽  
Articular Surface ◽  
Distribution Patterns ◽  
High Density ◽  
Soccer Players ◽  
Subchondral Bone Density

Background: The distribution pattern of subchondral bone density is considered to accurately reflect the stress distribution over a joint under long-term physiologic loading. The biomechanical characteristics of the surface of the ankle joint in soccer players can be determined by measuring this distribution pattern under long-term loading. Purpose: To evaluate the distribution of subchondral bone density across the ankle joint in soccer players and to determine the effects of soccer activities, including kicking motion, on the ankle joint surface under long-term loading conditions by computed tomography (CT) osteoabsorptiometry (CTOAM). Study Design: Cross-sectional study; Level of evidence, 3. Methods: CT imaging data were obtained from both ankles of 10 soccer players (soccer group) and 10 nonathletic volunteers (control group). The distribution patterns of subchondral bone density across the articular surface of the ankle joints were assessed by CTOAM. Quantitative analysis was performed of the locations and percentages of high-density areas on the articular surface. Results: Stress distribution patterns over the ankle joint differed between the soccer players and controls. In the soccer players, the high-density areas were found in the anterior part of the distal tibia and proximal talus as well as the distal fibula. The percentages of high-density areas were greater in the soccer players compared with controls ( P < .0001). Conclusion: Stress distribution over the articular surface of the ankle joint was affected by soccer activities. A high stress concentration was seen in soccer players in the anterior part of the tibia and talus and in the fibula; such excessive stress may lead to anterior impingement.

Comparison Between DEXA and Finite Element Studies in the Long-Term Bone Remodeling of an Anatomical Femoral Stem

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
A. Herrera ◽  
J. J. Panisello ◽  
E. Ibarz ◽  
J. Cegoñino ◽  
J. A. Puértolas ◽  
...  
Keyword(s):  
Finite Element ◽  
Bone Density ◽  
Bone Mass ◽  
Simulation Model ◽  
Load Transfer ◽  
Fe Simulation ◽  
Femoral Stem ◽  
Mineral Density ◽  
Biomechanical Behavior

The implantation of a cemented or cementless femoral stem changes the physiological load transfer on the femur producing an effect on the bone called adaptative remodeling. The patterns of this remodeling are attributed to mechanical and biological factors, and those changes in bone mineral density have been determined in long-term densitometry studies. This technique has proved to be a useful tool able to quantify small changes in bone density in different femoral areas, and it is considered to be ideal for long-term studies. On the other hand, the finite element (FE) simulation allows the study of the biomechanical changes produced in the femur after the implantation of a femoral stem. The aim of this study was to contrast the findings obtained from a 5 year follow-up densitometry study that used a newly designed femoral stem (73 patients were included in this study), with the results obtained using a finite element simulation that reproduces the pattern of load transfer that this stem causes on the femur. In this study we have obtained a good comparison between the results of stress of FE simulation and the bone mass values of the densitometry study establishing a ratio between the increases in stress (%) versus the increases in bone density (%). Hence, the changes in bone density in the long term, compared with the healthy femur, are due to different load transfers after stem implantation. It has been checked that in the Gruen zone 7 at 5 years, the most important reduction in stress (7.85%) is produced, which coincides with the highest loss of bone mass (23.89%). Furthermore, the simulation model can be used with different stems with several load conditions and at different time periods to carry out the study of biomechanical behavior in the interaction between the stem and the femur, explaining the evolution of bone density in accordance to Wolff’s law, which validates the simulation model.

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