| 1. |
- Forslind, Bo, et al.
(author)
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Aspects on the physiology of human skin : studies using particle probe analysis
- 1997
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In: Microscopy research and technique (Print). - 1059-910X .- 1097-0029. ; 38:4, s. 373-386
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Journal article (peer-reviewed)abstract
- The cellular part of the skin, the epidermis, is a very thin structure, approximately 120 microns thick, a fact which has hindered the exploration of the physiology of the epidermis in normal and pathological conditions. An additional complication is the fact that the epidermis contains layers of cells at different stages of differentiation. Therefore, conventional physiological capillary probes cannot, with any satisfactory precision, be located within a specified cell of a specified layer of the skin in vivo. Hence, alternative ways for the exploration of skin physiology have been sought for. In the past, analysis of the elemental content of skin was done was done as bulk measurements, and surprisingly wide ranges of elemental content were recorded. The width of these ranges was most certainly due to the sampling methods used rather than the sensitivity of the chosen method of analysis. Also, these older measurements did not discriminate between the different strata, and therefore the information provided little if any substance for a functional analysis of processes involved in normal and pathological differentiation of the epidermis. Particle probes, however, have been able to overcome such methodological problems. Over a period of 15 years we have studied normal human skin, normal-looking, paralesional skin from psoriatics, and skin from persons suffering from atopic dermatitis using PIXE analysis. In recent years, trace elements have been shown to work as secondary messengers or regulatory substances. As an example, calcium (Ca2+) has proven to be a very important signalling substance in a great variety of cellular systems. Studies with the transmission electron microscope (TEM) as well as histochemical methods have allowed an understanding of the role of Ca2+ in the differentiation process of the epidermis. Ca2+ has also been shown to play an important role in apoptosis (programmed cell death), which is currently a hot subject for the obvious reason that the final differentiation step between the stratum granulosum level and the stratum corneum represents a particular aspect of programmed cell death. The importance of the balance between calcium and zinc in apoptosis has been clearly demonstrated in a number of cellular systems, but we have still to clarify the validity of topical treatment with Zn ointments in different skin conditions. Substantial iron (Fe) losses via psoriatic lesions were demonstrated more than two decades ago, and these data were given new meaning when we found that a more discrete loss occurs in clinically normal-looking psoriatic skin. Obviously, such findings stress the importance of understanding the relation between the elemental content and normal and abnormal physiology. The ultimate goal of particle probe studies is to provide an understanding of the formation of a mature stratum corneum with a functional barrier reflected in physiological/biochemical mechanisms behind the properties of changed skin in patients afflicted with skin disorders of genetic or constitutional origin. This paper aims to give an overview of the state of the art in skin physiology made possible through the use of particle probes.
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| 2. |
- Forslind, Bo, et al.
(author)
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Elemental Analysis Mirrors Epidermal Differentiation
- 1999
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In: Acta Dermato-Venereologica. - : Medical Journals Sweden AB. - 0001-5555 .- 1651-2057. ; 79:1, s. 12-17
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Journal article (peer-reviewed)abstract
- Using a scanning nuclear microprobe, the distribution of elements and trace elements of skin cross sections of normal skin, non-lesional psoriatic skin and in dry atopic skin have been mapped. In non-lesional psoriatic skin and in dry atopic skin the epidermal Ca-gradient is higher than that of normal skin. In addition, abnormally high Fe and Zn levels were recorded in the stratum granulosum and corneum regions in the pathological skin. It is suggested that these findings correlate to an increased cell turnover in the basal cell layer of the psoriatic and atopic skins. The ratio of Ca/Zn in stratum corneum of paralesional psoriatic skin is approximately 8:1 compared to 12: 1 in normal skin and 15: 1 in atopic skin. This suggests that the differentiation process in paralesional psoriatic skin may actually be an example of disturbed programmed cell death.
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| 3. |
- Forslind, Bo, et al.
(author)
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Human skin physiology studied by particle probe microanalysis
- 1995
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In: Scanning Microscopy. - 0891-7035. ; 9:4, s. 1011-1025
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Journal article (peer-reviewed)abstract
- Particle probe methods (electron probe and proton probe X-ray microanalysis) have been applied to investigate the distribution of elements and water over the different layers of the epidermis. For major elements, electron probe X-ray microanalysis (XRMA) provides the advantage of superior spatial resolution, but for trace element analysis the more sensitive proton probe (particle induced X-ray emission, PIXE) analysis has to be used. On a dry weight basis, the concentration of S is rather constant across the epidermis, whereas the concentrations of P, K, Cl and Na show gradients with high levels in stratum germinativum (basale) and stratum spinosum but low levels in the stratum granulosum and stratum corneum. Essentially, Fe and Zn are confined to the basal region in normal skin. The concentration of Ca, however, increased steadily from the basal region to the stratum corneum. The probe technique allows quantitative analysis of stratum-specific changes in elemental content in a variety of pathological conditions, e.g., changes induced by nickel, detergents and other chemicals, or in psoriatic skin. Of particular interest are findings of increased Fe and Zn in non-involved psoriatic skin. Since the different layers of the skin have different elemental concentrations and react differently under pathological conditions, the probe techniques are far superior to bulk chemical analysis in elucidating physiological and pathological processes in the skin.
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