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2.
Biomed Opt Express ; 9(2): 852-872, 2018 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-29552418

RESUMEN

Finding a path towards a more accurate prediction of light propagation in human skin remains an aspiration of biomedical scientists working on cutaneous applications both for diagnostic and therapeutic reasons. The objective of this study was to investigate variability of the optical properties of human skin compartments reported in literature, to explore the underlying rational of this variability and to propose a dataset of values, to better represent an in vivo case and recommend a solution towards a more accurate prediction of light propagation through cutaneous compartments. To achieve this, we undertook a novel, logical yet simple approach. We first reviewed scientific articles published between 1981 and 2013 that reported on skin optical properties, to reveal the spread in the reported quantitative values. We found variations of up to 100-fold. Then we extracted the most trust-worthy datasets guided by a rule that the spectral properties should reflect the specific biochemical composition of each of the skin layers. This resulted in the narrowing of the spread in the calculated photon densities to 6-fold. We conclude with a recommendation to use the identified most robust datasets when estimating light propagation in human skin using Monte Carlo simulations. Alternatively, otherwise follow our proposed strategy to screen any new datasets to determine their biological relevance.

3.
Sci Rep ; 7(1): 2797, 2017 06 05.
Artículo en Inglés | MEDLINE | ID: mdl-28584230

RESUMEN

Photobiomodulation-based (LLLT) therapies show tantalizing promise for treatment of skin diseases. Confidence in this approach is blighted however by lamentable inconsistency in published experimental designs, and so complicates interpretation. Here we interrogate the appropriateness of a range of previously-reported treatment parameters, including light wavelength, irradiance and radiant exposure, as well as cell culture conditions (e.g., serum concentration, cell confluency, medium refreshment, direct/indirect treatment, oxygen concentration, etc.), in primary cultures of normal human dermal fibroblasts exposed to visible and near infra-red (NIR) light. Apart from irradiance, all study parameters impacted significantly on fibroblast metabolic activity. Moreover, when cells were grown at atmospheric O2 levels (i.e. 20%) short wavelength light inhibited cell metabolism, while negligible effects were seen with long visible and NIR wavelength. By contrast, NIR stimulated cells when exposed to dermal tissue oxygen levels (approx. 2%). The impact of culture conditions was further seen when inhibitory effects of short wavelength light were reduced with increasing serum concentration and cell confluency. We conclude that a significant source of problematic interpretations in photobiomodulation reports derives from poor optimization of study design. Further development of this field using in vitro/ex vivo models should embrace significant standardization of study design, ideally within a design-of-experiment setting.


Asunto(s)
Dermis/citología , Dermis/efectos de la radiación , Fibroblastos/metabolismo , Fibroblastos/efectos de la radiación , Luz , Metabolismo Energético/efectos de la radiación , Humanos , Consumo de Oxígeno , Fototerapia
4.
Clin Exp Dermatol ; 42(6): 656-658, 2017 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-28543400

RESUMEN

Sensitive skin (SS) is a widespread condition, but still not completely understood. To identify risk factors that increase the likelihood of SS, 258 women aged between 20 and 65 years old and resident in the Netherlands were surveyed by questionnaire, which included questions on sociodemographic characteristics (age group, Fitzpatrick skin type, hormonal status), health state (atopic predisposition, skin diseases) and lifestyle habits (history of smoking and of sun exposure, frequency of physical exercise). Analysis of the responses confirmed that atopic predisposition, presence of skin diseases and Fitzpatrick skin types I and II are risk factors significantly associated with SS. In addition, as current or past smoking and a history of low sun exposure showed a trend to increase the likelihood of reporting SS, we suggest that the potential role of lifestyle factors in the onset or exacerbation of SS should be investigated further.


Asunto(s)
Estilo de Vida , Enfermedades de la Piel/etiología , Trastornos Somatosensoriales/etiología , Adulto , Estudios Transversales , Ejercicio Físico , Femenino , Hábitos , Humanos , Hipersensibilidad/complicaciones , Persona de Mediana Edad , Pigmentación de la Piel , Luz Solar/efectos adversos , Encuestas y Cuestionarios , Adulto Joven
5.
J Eur Acad Dermatol Venereol ; 31(2): 267-273, 2017 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-27653746

RESUMEN

BACKGROUND: With high prevalence of sensitive skin (SS), lack of strong evidence on pathomechanisms, consensus on associated symptoms, proof of existence of 'general' SS and tools to recruit subjects, this topic attracts increasing attention of research. OBJECTIVE: To create a model for selecting subjects in studies on SS by identifying a complete set of self-reported SS characteristics and factors discriminatively describing it. METHODS: A survey (n = 3058) was conducted, comprising questions regarding socio-demographics, atopy, skin characteristics, personal care, degree of self-assessed SS and subjective and objective reactions to endogenous and exogenous factors. Exploratory factor analysis on 481 questionnaires was performed to identify underlying dimensions and multivariate logistic regression to find contributing variables to the likelihood of reporting SS. RESULTS: The prevalence of SS was found to be 41%, and 56% of SS subjects reports a concomitant atopic condition. The most discriminative were the eliciting factors toiletries and emotions, and not specific skin symptoms in general. CONCLUSION: Triggers of different origins seem to elicit SS, it is not defined by concomitant skin diseases only, suggesting existence of 'general' SS. A multifactorial questionnaire could be a better diagnostic than a one-dimensional provocative test.


Asunto(s)
Modelos Biológicos , Umbral Sensorial , Piel/fisiopatología , Adolescente , Adulto , Anciano , Vestuario , Frío , Emociones , Femenino , Remoción del Cabello , Calor , Humanos , Masculino , Persona de Mediana Edad , Prevalencia , Luz Solar , Adulto Joven
7.
Biophys J ; 84(6): 3968-81, 2003 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-12770902

RESUMEN

Nonresonant confocal Raman imaging has been used to map the DNA and the protein distributions in individual single human cells. The images are obtained on an improved homebuilt confocal Raman microscope. After statistical analysis, using singular value decomposition, the Raman images are reconstructed from the spectra covering the fingerprint region. The data are obtained at a step interval of approximately 250 nm and cover a field from 8- to 15- micro m square in size. Dwell times at each pixel are between 0.5 and 2 s, depending on the nature and the state of the cell under investigation. High quality nonresonant Raman images can only be obtained under these conditions using continuous wave high laser powers between 60 and 120 mW. We will present evidence that these laser powers can still safely be used to recover the chemical distributions in fixed cells. The developed Raman imaging method is used to image directly, i.e., without prior labeling, the nucleotide condensation and the protein distribution in the so-called nuclear fragments of apoptotic HeLa cells. In the control (nonapoptotic) HeLa cells, we show, for the first time by Raman microspectroscopy, the presence of the RNA in a cell nucleus.


Asunto(s)
Apoptosis/fisiología , ADN/metabolismo , Leucocitos Mononucleares/metabolismo , Microscopía Fluorescente/métodos , Fosfolípidos/metabolismo , Proteínas/metabolismo , Espectrometría Raman/métodos , Apoptosis/efectos de la radiación , Células Cultivadas , Estudios de Factibilidad , Células HeLa/citología , Células HeLa/metabolismo , Células HeLa/efectos de la radiación , Humanos , Rayos Láser , Leucocitos Mononucleares/citología , Leucocitos Mononucleares/efectos de la radiación , Microscopía Fluorescente/instrumentación , Espectrometría Raman/instrumentación , Distribución Tisular
8.
Biopolymers ; 72(1): 1-9, 2003.
Artículo en Inglés | MEDLINE | ID: mdl-12400086

RESUMEN

A confocal Raman microscope is used to study the protein distribution inside biological cells. It is shown that high quality Raman imaging of the protein distribution can be obtained using confocal nonresonant Raman imaging (lambda(exc) = 647.1 nm). The results are shown for two different human cell types. Perpheral blood lymphocytes are used as an example of the fully maturated cells with a low level of nuclear transcription. Human eye lens epithelial cells are used as an example of cells with a high level of nuclear activity. The protein distribution in both cell types is completely different. The nuclear distribution of the protein largely varies in the peripheral blood lymphocyte cells, while proteins are more homogenously distributed over the nuclear space in the eye lens epithelial cells. The imaging time is approximately 20 min for a field of view of 10 x 10 microm(2). The size of the sampling volume is 1.4 fL using a full width at half-maximum criterion along the z axis and a 1/e(2) criterion in the xy plane. The results presented here indicate that Raman imaging is particularly of interest in the study of cellular processes, like phagocytosis, apoptosis, chromatin compaction, and cellular differentiation, which are accompanied by relatively large-scale redistributions of the materials.


Asunto(s)
Núcleo Celular/química , Microscopía Confocal/métodos , Proteínas/análisis , Espectrometría Raman/métodos , Células Epiteliales/química , Células Epiteliales/citología , Humanos , Cristalino/química , Cristalino/citología , Linfocitos/química , Linfocitos/citología
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