Seasonal Changes in the IGF Regulatory System and The Relationship to Bone Loss in Elderly Women

2002 ◽  
pp. 151-154
Author(s):  
Clifford J. Rosen ◽  
Subburaman Mohan ◽  
Michael F. Holick
Keyword(s):  
Bone Loss ◽  
Seasonal Changes ◽  
Elderly Women ◽  
Regulatory System ◽  
The Relationship

The relationship of severe health disorders with bone loss, grip strength, and mobility in postmenopausal women – a 15-year follow-up study

2015 ◽  
Vol 38 (14) ◽  
pp. 1407-1414
Author(s):  
Juha Suuronen ◽  
Samu Sjöblom ◽  
Risto Honkanen ◽  
Heli Koivumaa-Honkanen ◽  
Heikki Kröger ◽  
...  
Keyword(s):  
Bone Loss ◽  
Grip Strength ◽  
Postmenopausal Women ◽  
Follow Up Study ◽  
Health Disorders ◽  
Relationship Of ◽  
The Relationship

scholarly journals The plate-to-rod transition in trabecular bone loss is elusive

2021 ◽  
Vol 8 (6) ◽  
pp. 201401
Author(s):  
A. A. Felder ◽  
S. Monzem ◽  
R. De Souza ◽  
B. Javaheri ◽  
D. Mills ◽  
...  
Keyword(s):  
Bone Loss ◽  
Trabecular Bone ◽  
Volume Fraction ◽  
Bone Volume ◽  
Continuous Measure ◽  
Bone Volume Fraction ◽  
Trabecular Bone Loss ◽  
Mouse Tibia ◽  
Disease Stages ◽  
The Relationship

Changes in trabecular micro-architecture are key to our understanding of osteoporosis. Previous work focusing on structure model index (SMI) measurements have concluded that disease progression entails a shift from plates to rods in trabecular bone, but SMI is heavily biased by bone volume fraction. As an alternative to SMI, we proposed the ellipsoid factor (EF) as a continuous measure of local trabecular shape between plate-like and rod-like extremes. We investigated the relationship between EF distributions, SMI and bone volume fraction of the trabecular geometry in a murine model of disuse osteoporosis as well as from human vertebrae of differing bone volume fraction. We observed a moderate shift in EF median (at later disease stages in mouse tibia) and EF mode (in the vertebral samples with low bone volume fraction) towards a more rod-like geometry, but not in EF maximum and minimum. These results support the notion that the plate to rod transition does not coincide with the onset of bone loss and is considerably more moderate, when it does occur, than SMI suggests. A variety of local shapes not straightforward to categorize as rod or plate exist in all our trabecular bone samples.

Cooperative attachment of cross bridges predicts regulation of smooth muscle force by myosin phosphorylation

2004 ◽  
Vol 287 (3) ◽  
pp. C594-C602 ◽  
Author(s):  
Christopher M. Rembold ◽  
Robert L. Wardle ◽  
Christopher J. Wingard ◽  
Timothy W. Batts ◽  
Elaine F. Etter ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Smooth Muscle ◽  
Time Course ◽  
Muscle Force ◽  
Regulatory System ◽  
Force Development ◽  
Cross Bridge ◽  
Cross Bridges ◽  
The Relationship ◽  
Cooperative Activation

Serine 19 phosphorylation of the myosin regulatory light chain (MRLC) appears to be the primary determinant of smooth muscle force development. The relationship between MRLC phosphorylation and force is nonlinear, showing that phosphorylation is not a simple switch regulating the number of cycling cross bridges. We reexamined the MRLC phosphorylation-force relationship in slow, tonic swine carotid media; fast, phasic rabbit urinary bladder detrusor; and very fast, tonic rat anococcygeus. We found a sigmoidal dependence of force on MRLC phosphorylation in all three tissues with a threshold for force development of ∼0.15 mol Pi/mol MRLC. This behavior suggests that force is regulated in a highly cooperative manner. We then determined whether a model that employs both the latch-bridge hypothesis and cooperative activation could reproduce the relationship between Ser19-MRLC phosphorylation and force without the need for a second regulatory system. We based this model on skeletal muscle in which attached cross bridges cooperatively activate thin filaments to facilitate cross-bridge attachment. We found that such a model describes both the steady-state and time-course relationship between Ser19-MRLC phosphorylation and force. The model required both cooperative activation and latch-bridge formation to predict force. The best fit of the model occurred when binding of a cross bridge cooperatively activated seven myosin binding sites on the thin filament. This result suggests cooperative mechanisms analogous to skeletal muscle that will require testing.

Terrestrial arthropod abundance and phenology in the Canadian Arctic: modelling resource availability for Arctic-nesting insectivorous birds

2013 ◽  
Vol 145 (2) ◽  
pp. 155-170 ◽  
Author(s):  
Elise Bolduc ◽  
Nicolas Casajus ◽  
Pierre Legagneux ◽  
Laura McKinnon ◽  
H. Grant Gilchrist ◽  
...  
Keyword(s):  
Seasonal Changes ◽  
Canadian Arctic ◽  
Insectivorous Birds ◽  
Weather Variables ◽  
Degree Day ◽  
Terrestrial Arthropods ◽  
Bird Breeding ◽  
Using Data ◽  
The Relationship ◽  
Arthropod Abundance

AbstractArctic arthropods are essential prey for many vertebrates, including birds, but arthropod populations and phenology are susceptible to climate change. The objective of this research was to model the relationship between seasonal changes in arthropod abundance and weather variables using data from a collaborative pan-Canadian (Southampton, Herschel, Bylot, and Ellesmere Islands) study on terrestrial arthropods. Arthropods were captured with passive traps that provided a combined measure of abundance and activity (a proxy for arthropod availability to foraging birds). We found that 70% of the deviance in daily arthropod availability was explained by three temperature covariates: mean daily temperature, thaw degree-day, and thaw degree-day2. Models had an adjusted R2 of 0.29–0.95 with an average among sites and arthropod families of 0.67. This indicates a moderate to strong fit to the raw data. The models for arthropod families with synchronous emergence, such as Tipulidae (Diptera), had a better fit (average adjusted R2 of 0.80) than less synchronous taxa, such as Araneae (R2 = 0.60). Arthropod abundance was typically higher in wet than in mesic habitats. Our models will serve as tools for researchers who want to correlate insectivorous bird breeding data to arthropod availability in the Canadian Arctic.

scholarly journals The Relationship between Maxillary Sinus Lateral Wall Thickness, Alveolar Bone Loss, and Demographic Variables: A Cross-Sectional Cone-Beam Computerized Tomography Study

2018 ◽  
Vol 28 (2) ◽  
pp. 109-114 ◽  
Author(s):  
Tuba Talo Yildirim ◽  
Güliz Nigar Güncü ◽  
Mehmet Colak ◽  
Tolga Fikret Tözüm
Keyword(s):  
Bone Loss ◽  
Maxillary Sinus ◽  
Computerized Tomography ◽  
Wall Thickness ◽  
Alveolar Bone ◽  
Lateral Wall ◽  
Cone Beam ◽  
Cone Beam Computerized Tomography ◽  
And Gender ◽  
The Relationship

Objectives: Sinus floor elevation and augmentation surgery is widely used as a reliable procedure to increase insufficient bone height in the posterior maxillary area. The purpose of the present clinical study was to determine the associations between periodontal bone loss (PBL), maxillary sinus lateral bone wall thickness, age, and gender using cone-beam computerized tomography (CBCT). Materials and Methods: The current retrospective study consists of 716 maxillary sinus CBCT images of 358 patients. The CBCT scans were assessed to detect the relationship between lateral wall thickness and PBL. ANOVA and Student t test analysis were used to determine the influence of PBL on sinus lateral wall thickness. Results: Sinus lateral wall thickness was significantly associated with PBL (p < 0.05) at 3, 13, and 15 mm height. There was no significant association between lateral wall thickness and gender (p > 0.05). However, there was a significant association between lateral wall thickness at 3 and 13 mm and age (p < 0.05). There were significant associations between PBL and age (p < 0.001), and PBL and gender (p < 0.05). Conclusions: PBL might have an association with maxillary sinus lateral bone wall thickness. Further studies are needed to confirm this possible relationship.

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