Linked Life Data

12808646

Source:http://linkedlifedata.com/resource/pubmed/id/12808646

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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2003-6-16
pubmed:abstractText
This study examines relationships between bone morphology and mechanically mediated strain/fluid-flow patterns in an avian species. Using mid-diaphyseal transverse sections of domestic turkey ulnae (from 11 subadults and 11 adults), we quantified developmental changes in predominant collagen fiber orientation (CFO), mineral content (%ash), and microstructure in cortical octants or quadrants (i.e., %ash). Geometric parameters were examined using whole mid-diaphyseal cross-sections. The ulna undergoes habitual bending and torsion, and demonstrates nonuniform matrix fluid-flow patterns, and high circumferential strain gradients along the neutral axis (cranial-caudal) region at mid-diaphysis. The current results showed significant porosity differences: 1) greater osteocyte lacuna densities (N.Lac/Ar) (i.e., "non-vascular porosity") in the caudal and cranial cortices in both groups, 2) greater N.Lac/Ar in the pericortex vs. endocortex in mature bones, and 3) greater nonlacunar porosity (i.e., "vascular porosity") in the endocortex vs. pericortex in mature bones. Vascular and nonvascular porosities were not correlated. There were no secondary osteons in subadults. In adults, the highest secondary osteon population densities and lowest %ash occurred in the ventral-caudal, caudal, and cranial cortices, where shear strains, circumferential strain gradients, and fluid displacements are highest. Changes in thickness of the caudal cortex explained the largest proportion of the age-related increase in cranial-caudal breadth; the thickness of other cortices (dorsal, ventral, and cranial) exhibited smaller changes. Only subadult bones exhibited CFO patterns corresponding to habitual tension (ventral) and compression (dorsal). These CFO variations may be adaptations for differential mechanical requirements in "strain-mode-specific" loading. The more uniform oblique-to-transverse CFO patterns in adult bones may represent adaptations for shear strains produced by torsional loading, which is presumably more prevalent in adults. The micro- and ultrastructural heterogeneities may influence strain and fluid-flow dynamics, which are considered proximate signals in bone adaptation.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
1552-4884
pubmed:author
pubmed:copyrightInfo
Copyright 2003 Wiley-Liss, Inc.
pubmed:issnType
Print
pubmed:volume
273
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
609-29
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2003
pubmed:articleTitle
Ontogenetic and regional morphologic variations in the turkey ulna diaphysis: implications for functional adaptation of cortical bone.
pubmed:affiliation
Bone and Joint Research Laboratory, Department of Veterans Affairs Medical Center, Salt Lake City, Utah 84148, USA. jskedros@utahboneandjoint.com
pubmed:publicationType
Journal Article, Comparative Study, Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't