Lipofuscin-Type Pigment as a Marker of Colorectal Cancer

Carvalho, Sónia; Carneiro, Isa; Henrique, Rui; Tuchin, Valery V.; Oliveira, Luís

doi:10.20944/preprints202010.0306.v1

Cited by 3 publications

(11 citation statements)

References 26 publications

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“…The optical properties of biological tissues are unique to those tissues and provide means for their identification. The estimation of their wavelength dependence allows the identification of biological components in tissues and the discrimination of pathologies [1]. There are various optical properties, but the most commonly used to characterize a biological tissue are the refractive index (RI), the absorption coefficient (µa), the scattering coefficient (µs) or the reduced scattering coefficient (µ's) and the scattering anisotropy (g) [2,3].…”

Section: Introductionmentioning

confidence: 99%

“…This means that a fast way to obtain the optical properties of a tissue for a wide spectral range is necessary. As recently published [1,9], if some spectral measurements from the tissue samples are available, certain equations can be used for a fast calculation of such properties. Considering µa, its spectrum can be calculated from the total transmittance (Tt) and total reflectance (Rt) spectra that were measured from a tissue.…”

Section: Introductionmentioning

confidence: 99%

“…Considering µa, its spectrum can be calculated from the total transmittance (Tt) and total reflectance (Rt) spectra that were measured from a tissue. Equation ( 1) describes such calculation [1]:…”

Section: Introductionmentioning

confidence: 99%

“…Once µa(λ) is calculated with Equation (1), and if collimated transmittance (Tc) spectra from the tissue are available, then the Bouguer-Beer-Lambert law can be used to calculate µs(λ) for the same wavelength range [1][2][3]:…”

Section: Introductionmentioning

confidence: 99%

“…By running those simulations, the generated µ's values are then fitted with Equation ( 3) to obtain µ's(λ). Such data can be combined with the calculated µs spectrum to obtain the wavelength dependence of tissue scattering anisotropy (g(λ)) [1][2][3]17]:…”

Section: Introductionmentioning

confidence: 99%

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Spectral Optical Properties of Rabbit Brain Cortex Between 200 and 1000 nm

Gonçalves¹,

Martins²,

Silva³

et al. 2021

Preprint

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The knowledge of the optical properties of biological tissues in a wide spectral range is highly important for the development of noninvasive diagnostic or treatment procedures. The absorption coefficient is one of those properties, from which various information about tissue components can be retrieved. Using transmittance and reflectance spectral measurements acquired from ex vivo rabbit brain cortex samples, allowed to calculate its optical properties in the ultraviolet to the near infrared spectral range. Melanin and lipofuscin, the two pigments that are related to the ageing of tissues and cells were identified in the cortex absorption. By subtracting the absorption of these pigments from the absorption of the brain cortex, it was possible to evaluate the true ratios for the DNA/RNA and hemoglobin bands in the cortex – 12.33 fold (at 260 nm), 12.02 fold (at 411 nm) and 4.47 fold (at 555 nm). Due to the fact that the accumulation of melanin and lipofuscin increases with the ageing of the brain tissues and are related to the degeneration of neurons and their death, further studies should be performed to evaluate the evolution of pigment accumulation in the brain to prevent the development of Alzheimer, Parkinson and stroke pathologies in the brain.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Spectral Optical Properties of Rabbit Brain Cortex Between 200 and 1000 nm

Gonçalves¹,

Martins²,

Silva³

et al. 2021

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

Spectral Optical Properties of Rabbit Brain Cortex between 200 and 1000 nm

et al. 2021

View full text Add to dashboard Cite

The knowledge of the optical properties of biological tissues in a wide spectral range is highly important for the development of noninvasive diagnostic or treatment procedures. The absorption coefficient is one of those properties, from which various information about tissue components can be retrieved. Using transmittance and reflectance spectral measurements acquired from ex vivo rabbit brain cortex samples allowed to calculate its optical properties in the ultraviolet to the near infrared spectral range. Melanin and lipofuscin, the two pigments that are related to the aging of tissues and cells were identified in the cortex absorption. By subtracting the absorption of these pigments from the absorption of the brain cortex, it was possible to evaluate the true ratios for the DNA/RNA and hemoglobin bands in the cortex—12.33-fold (at 260 nm), 12.02-fold (at 411 nm) and 4.47-fold (at 555 nm). Since melanin and lipofuscin accumulation increases with the aging of the brain tissues and are related to the degeneration of neurons and their death, further studies should be performed to evaluate the evolution of pigment accumulation in the brain, so that new optical methods can be developed to aid in the diagnosis and monitoring of brain diseases.

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Fast Estimation of the Spectral Optical Properties of Rabbit Pancreas and Pigment Content Analysis

et al. 2022

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The pancreas is a highly important organ, since it produces insulin and prevents the occurrence of diabetes. Although rare, pancreatic cancer is highly lethal, with a small life expectancy after being diagnosed. The pancreas is one of the organs less studied in the field of biophotonics. With the objective of acquiring information that can be used in the development of future applications to diagnose and treat pancreas diseases, the spectral optical properties of the rabbit pancreas were evaluated in a broad-spectral range, between 200 and 1000 nm. The method used to obtain such optical properties is simple, based almost on direct calculations from spectral measurements. The optical properties obtained show similar wavelength dependencies to the ones obtained for other tissues, but a further analysis on the spectral absorption coefficient showed that the pancreas tissues contain pigments, namely melanin, and lipofuscin. Using a simple calculation, it was possible to retrieve similar contents of these pigments from the absorption spectrum of the pancreas, which indicates that they accumulate in the same proportion as a result of the aging process. Such pigment accumulation was camouflaging the real contents of DNA, hemoglobin, and water, which were precisely evaluated after subtracting the pigment absorption.

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Lipofuscin-Type Pigment as a Marker of Colorectal Cancer

Cited by 3 publications

References 26 publications

Spectral Optical Properties of Rabbit Brain Cortex Between 200 and 1000 nm

Spectral Optical Properties of Rabbit Brain Cortex Between 200 and 1000 nm

Spectral Optical Properties of Rabbit Brain Cortex between 200 and 1000 nm

Fast Estimation of the Spectral Optical Properties of Rabbit Pancreas and Pigment Content Analysis

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