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Biomedical subjects

G Zonios

Publications and source records attributed to G Zonios.

5 recordsLinked to original sources
PubMed2001

Skin melanin, hemoglobin, and light scattering properties can be quantitatively assessed in vivo using diffuse reflectance spectroscopy.

Noninvasive and real-time analysis of skin properties is useful in a wide variety of applications. In particular, the quantitative assessment of skin in terms of hemoglobin and melanin content, as well as in terms of its light scattering properties, is a challenging problem in dermatology. We present here a technique for examining human skin, based on the in vivo measurement of diffuse reflectance spectra in the visible and near-infrared ranges of the electromagnetic spectrum. Spectra were measured by means of a fiber optic probe, and they were analyzed using an analytical model of light diffusion in the skin. The results of the analysis indicate that it is possible to obtain quantitative information about hemoglobin and melanin content, as well as basic information regarding the scattering properties of the skin.

Fiber Optic Technology↗
PubMed2000

Endogenous skin fluorescence is a good marker for objective evaluation of comedolysis.

OBJECTIVE: evaluation of comedone lesions, especially in vivo, remains a challenge. We have used the rhino mouse model in combination with topical application of all-trans retinoic acid as a comedolytic agent, to investigate the potential of fluorescence spectroscopy as a noninvasive technique in the assessment of noninflammatory acne. The results indicate that there is a strong correlation between the fluorescence excitation spectral features assessed in vivo, and the histologic changes identified, particularly the size of the utriculi as well as the dermal and epidermal thickness. We conclude that fluorescence excitation spectroscopy represents a promising novel and useful tool in the quantitative evaluation of the pseudocomedones and could also be used for the rapid and noninvasive assessment of comedolysis induced by the application of pharmacologic agents such as retinoids.

Acne Vulgaris↗
PubMed2000

Fluorescence excitation spectroscopy provides information about human skin in vivo.

Fluorescence spectroscopy of human skin has the potential to provide useful morphologic and biochemical information. The endogenous fluorescence of human skin has been investigated in vivo on normal human volunteers as well as on patients with psoriasis and it was found that characteristic bands can be identified in the fluorescence spectra that are associated with specific skin fluorophores. One epidermal band (295 nm excitation, attributed to tryptophan) and two dermal bands (335 and 370 nm excitation, attributed to collagen cross-links) were consistently present in all fluorescence spectra. In addition, the fluorescence spectra obtained from lesions and nonlesional sites of psoriatic patients differed from those obtained from healthy volunteers and the hyperproliferative state of the lesions was characterized by a significantly larger signal at 295 nm excitation. These results indicate that fluorescence spectroscopy is a promising technique for the investigation of human skin in vivo.

Adult↗
PubMed1998

Spectral pathology.

We are investigating the use of optical spectroscopy (fluorescence, reflectance, Raman scattering) for detecting precancerous lesions in the mucosal linings of hollow organs. We present a morphological model for extracting quantitative pathological information from fluorescence spectra, using colonic dysplasia as an example. The potential of this technique in providing histological information in real time without the need for tissue removal is discussed.

Humans↗