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Fourier-transform infrared anisotropy in cross and parallel sections of tendon and articular cartilage.

Ramakrishnan N, Xia Y, Bidthanapally A - J Orthop Surg Res (2008)

Bottom Line: With the change in the polarization state of the incident infrared light, the resulting anisotropic behavior of the tissue structure is described here.The parallel sections in the radial zone, however, have a nearly isotropic amide II absorption and a distinct amide I anisotropy.From the inconsistency in amide anisotropy between superficial to radial zone in parallel section results, a schematic model is used to explain the origins of these amide anisotropies in cartilage and tendon.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physics and Center for Biomedical Research, Oakland University, Rochester, MI 48309, USA.

ABSTRACT

Background: Fourier Transform Infrared Imaging (FTIRI) is used to investigate the amide anisotropies at different surfaces of a three-dimensional cartilage or tendon block. With the change in the polarization state of the incident infrared light, the resulting anisotropic behavior of the tissue structure is described here.

Methods: Thin sections (6 mum thick) were obtained from three different surfaces of the canine tissue blocks and imaged at 6.25 microm pixel resolution. For each section, infrared imaging experiments were repeated thirteen times with the identical parameters except a 15 degrees increment of the analyzer's angle in the 0 degrees-180 degrees angular space. The anisotropies of amide I and amide II components were studied in order to probe the orientation of the collagen fibrils at different tissue surfaces.

Results: For tendon, the anisotropy of amide I and amide II components in parallel sections is comparable to that of regular sections; and tendon's cross sections show distinct, but weak anisotropic behavior for both the amide components. For articular cartilage, parallel sections in the superficial zone have the expected infrared anisotropy that is consistent with that of regular sections. The parallel sections in the radial zone, however, have a nearly isotropic amide II absorption and a distinct amide I anisotropy.

Conclusion: From the inconsistency in amide anisotropy between superficial to radial zone in parallel section results, a schematic model is used to explain the origins of these amide anisotropies in cartilage and tendon.

No MeSH data available.


Related in: MedlinePlus

(a) The transitional moments of one pair of amide bonds at one location in the triple helix. The distribution of numerous amide bonds along the fibril axis would be similar to the cone structures as in (b). When the long axis of the fibrils is parallel to tissue section (b), the 'projection' of the transition moment 'cone' varies its size at the 2D z-z' plane with the change of polarization state. Consequently, there will be infrared anisotropy in (b). When the long axis of the fibrils is perpendicular to the tissue section (c), the 'projection' of the transition moment 'cone' remains the same at the 2D z' plane regardless of the polarization state. Consequently, there will be no infrared anisotropy in (c).
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Figure 7: (a) The transitional moments of one pair of amide bonds at one location in the triple helix. The distribution of numerous amide bonds along the fibril axis would be similar to the cone structures as in (b). When the long axis of the fibrils is parallel to tissue section (b), the 'projection' of the transition moment 'cone' varies its size at the 2D z-z' plane with the change of polarization state. Consequently, there will be infrared anisotropy in (b). When the long axis of the fibrils is perpendicular to the tissue section (c), the 'projection' of the transition moment 'cone' remains the same at the 2D z' plane regardless of the polarization state. Consequently, there will be no infrared anisotropy in (c).

Mentions: In infrared polarization experiments with cartilage/tendon, maximum and minimum absorption occurs when the polarization axis is parallel and perpendicular to amide bond transition moment directions respectively. Our previous results have verified such anisotropy for both amide I and amide II components using the regular sections of cartilage, as illustrated in Figure 1b1. To investigate infrared anisotropy for the tissue sections where the long axis of the fibrils is perpendicular to the section plane, such simple illustration is not sufficient. Hence, a detailed illustration is given in Figure 7, which incorporates the tilting angles of the transitional moments of amide bonds in collagen fibrils as well as the effect of polarization in infrared imaging.


Fourier-transform infrared anisotropy in cross and parallel sections of tendon and articular cartilage.

Ramakrishnan N, Xia Y, Bidthanapally A - J Orthop Surg Res (2008)

(a) The transitional moments of one pair of amide bonds at one location in the triple helix. The distribution of numerous amide bonds along the fibril axis would be similar to the cone structures as in (b). When the long axis of the fibrils is parallel to tissue section (b), the 'projection' of the transition moment 'cone' varies its size at the 2D z-z' plane with the change of polarization state. Consequently, there will be infrared anisotropy in (b). When the long axis of the fibrils is perpendicular to the tissue section (c), the 'projection' of the transition moment 'cone' remains the same at the 2D z' plane regardless of the polarization state. Consequently, there will be no infrared anisotropy in (c).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2570663&req=5

Figure 7: (a) The transitional moments of one pair of amide bonds at one location in the triple helix. The distribution of numerous amide bonds along the fibril axis would be similar to the cone structures as in (b). When the long axis of the fibrils is parallel to tissue section (b), the 'projection' of the transition moment 'cone' varies its size at the 2D z-z' plane with the change of polarization state. Consequently, there will be infrared anisotropy in (b). When the long axis of the fibrils is perpendicular to the tissue section (c), the 'projection' of the transition moment 'cone' remains the same at the 2D z' plane regardless of the polarization state. Consequently, there will be no infrared anisotropy in (c).
Mentions: In infrared polarization experiments with cartilage/tendon, maximum and minimum absorption occurs when the polarization axis is parallel and perpendicular to amide bond transition moment directions respectively. Our previous results have verified such anisotropy for both amide I and amide II components using the regular sections of cartilage, as illustrated in Figure 1b1. To investigate infrared anisotropy for the tissue sections where the long axis of the fibrils is perpendicular to the section plane, such simple illustration is not sufficient. Hence, a detailed illustration is given in Figure 7, which incorporates the tilting angles of the transitional moments of amide bonds in collagen fibrils as well as the effect of polarization in infrared imaging.

Bottom Line: With the change in the polarization state of the incident infrared light, the resulting anisotropic behavior of the tissue structure is described here.The parallel sections in the radial zone, however, have a nearly isotropic amide II absorption and a distinct amide I anisotropy.From the inconsistency in amide anisotropy between superficial to radial zone in parallel section results, a schematic model is used to explain the origins of these amide anisotropies in cartilage and tendon.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physics and Center for Biomedical Research, Oakland University, Rochester, MI 48309, USA.

ABSTRACT

Background: Fourier Transform Infrared Imaging (FTIRI) is used to investigate the amide anisotropies at different surfaces of a three-dimensional cartilage or tendon block. With the change in the polarization state of the incident infrared light, the resulting anisotropic behavior of the tissue structure is described here.

Methods: Thin sections (6 mum thick) were obtained from three different surfaces of the canine tissue blocks and imaged at 6.25 microm pixel resolution. For each section, infrared imaging experiments were repeated thirteen times with the identical parameters except a 15 degrees increment of the analyzer's angle in the 0 degrees-180 degrees angular space. The anisotropies of amide I and amide II components were studied in order to probe the orientation of the collagen fibrils at different tissue surfaces.

Results: For tendon, the anisotropy of amide I and amide II components in parallel sections is comparable to that of regular sections; and tendon's cross sections show distinct, but weak anisotropic behavior for both the amide components. For articular cartilage, parallel sections in the superficial zone have the expected infrared anisotropy that is consistent with that of regular sections. The parallel sections in the radial zone, however, have a nearly isotropic amide II absorption and a distinct amide I anisotropy.

Conclusion: From the inconsistency in amide anisotropy between superficial to radial zone in parallel section results, a schematic model is used to explain the origins of these amide anisotropies in cartilage and tendon.

No MeSH data available.


Related in: MedlinePlus