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Multilamellar spherical particles as potential sources of excessive light scattering in human age-related nuclear cataracts.

Publication ,  Journal Article
Costello, MJ; Johnsen, S; Metlapally, S; Gilliland, KO; Frame, L; Balasubramanian, D
Published in: Exp Eye Res
December 2010

The goal of this project was to determine the relative refractive index (RI) of the interior of multilamellar bodies (MLBs) compared to the adjacent cytoplasm within human nuclear fiber cells. MLBs have been characterized previously as 1-4 μm diameter spherical particles covered by multiple lipid bilayers surrounding a cytoplasmic core of variable density. Age-related nuclear cataracts have more MLBs than transparent donor lenses and were predicted to have high forward scattering according to Mie scattering theory, assuming different RIs for the MLB and cytoplasm. In this study quantitative values of relative RI were determined from specific MLBs in electron micrographs of thin sections and used to calculate new Mie scattering plots. Fresh lenses were Vibratome sectioned, immersion fixed and en bloc stained with osmium tetroxide and uranyl acetate, or uranyl acetate alone, prior to dehydration and embedding in epoxy or acrylic resins. Thin sections 70 nm thick were cut on a diamond knife and imaged without grid stains at 60 kV using a CCD camera on a transmission electron microscope (TEM). Integrated intensities in digital electron micrographs were related directly to protein density, which is linearly related to RI for a given substance. The RI of the MLB interior was calculated assuming an RI value of 1.42 for the cytoplasm from the literature. Calculated RI values for MLBs ranged from 1.35 to 1.53. Thus, some MLBs appeared to have interior protein densities similar to or less than the adjacent cytoplasm whereas others had significantly higher densities. The higher density MLBs occurred preferentially in older and more advanced cataracts suggesting a maturation process. The bilayer coats were more often observed in MLBs from transparent donors and early stage cataracts indicating that bilayer loss was part of the MLB maturation, producing large low-density spaces around dense MLB cores. These spaces were frequently observed in advanced cataracts from India as large low-density crescents and annular rings. Predicted scattering from Mie plots using particles with dense cores and low-density rims was higher than reported previously, although the most important factor was the relative RI, not the MLB coat or lack thereof. In conclusion, the measurements confirm the high protein density and RI of some MLB interiors compared to adjacent cytoplasm. This high RI ratio used in the Mie calculations suggests that for 2000 MLBs/mm³, about half that reported for early stage nuclear cataracts from the US, the forward scattering could be more than 30% of the incident light. Therefore, the extent of forward scattering and its influence on macular visual acuity could be important components of ophthalmological evaluations of cataract patients.

Duke Scholars

Published In

Exp Eye Res

DOI

EISSN

1096-0007

Publication Date

December 2010

Volume

91

Issue

6

Start / End Page

881 / 889

Location

England

Related Subject Headings

  • Scattering, Radiation
  • Refraction, Ocular
  • Ophthalmology & Optometry
  • Middle Aged
  • Microscopy, Electron, Transmission
  • Lipid Bilayers
  • Light
  • Lens Nucleus, Crystalline
  • Inclusion Bodies
  • Humans
 

Citation

APA
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ICMJE
MLA
NLM
Costello, M. J., Johnsen, S., Metlapally, S., Gilliland, K. O., Frame, L., & Balasubramanian, D. (2010). Multilamellar spherical particles as potential sources of excessive light scattering in human age-related nuclear cataracts. Exp Eye Res, 91(6), 881–889. https://doi.org/10.1016/j.exer.2010.09.013
Costello, M Joseph, Sönke Johnsen, Sangeetha Metlapally, Kurt O. Gilliland, Lesley Frame, and Dorairajan Balasubramanian. “Multilamellar spherical particles as potential sources of excessive light scattering in human age-related nuclear cataracts.Exp Eye Res 91, no. 6 (December 2010): 881–89. https://doi.org/10.1016/j.exer.2010.09.013.
Costello MJ, Johnsen S, Metlapally S, Gilliland KO, Frame L, Balasubramanian D. Multilamellar spherical particles as potential sources of excessive light scattering in human age-related nuclear cataracts. Exp Eye Res. 2010 Dec;91(6):881–9.
Costello, M. Joseph, et al. “Multilamellar spherical particles as potential sources of excessive light scattering in human age-related nuclear cataracts.Exp Eye Res, vol. 91, no. 6, Dec. 2010, pp. 881–89. Pubmed, doi:10.1016/j.exer.2010.09.013.
Costello MJ, Johnsen S, Metlapally S, Gilliland KO, Frame L, Balasubramanian D. Multilamellar spherical particles as potential sources of excessive light scattering in human age-related nuclear cataracts. Exp Eye Res. 2010 Dec;91(6):881–889.
Journal cover image

Published In

Exp Eye Res

DOI

EISSN

1096-0007

Publication Date

December 2010

Volume

91

Issue

6

Start / End Page

881 / 889

Location

England

Related Subject Headings

  • Scattering, Radiation
  • Refraction, Ocular
  • Ophthalmology & Optometry
  • Middle Aged
  • Microscopy, Electron, Transmission
  • Lipid Bilayers
  • Light
  • Lens Nucleus, Crystalline
  • Inclusion Bodies
  • Humans