Clinical Applications of Scanning Electron Microscopy and Energy Dispersive X-Ray Analysis in Dermatology - An Up-Date

Dermatological papers comprising scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis data published 1983 through 1986 in international journals are reviewed, as an update to our 1984 paper on Clinical applications of scanning electron microscopy and X-ray microanalysis in dermatology. The present paper not only deals with a review of recent publications in this area but also presents the application of microincineration to hair and cryosectioned freeze-dried skin specimens. Examples of the increased contrast obtained in hair cross sections are presented and a discussion on the feasibility of microincineration at analysis of hair and skin cross sections is given. Particle probe analysis (EDX: energy dispersive X-ray analysis and PMP: proton microprobe analysis) as applied to hair and skin samples are presented with stress put on the proton probe analysis. The complementarity of EDX and PMP is demonstrated and future applications are suggested

The Use of Scanning Electron Microscopy in the Analysis of Pathological Hairs

The potentials of the scanning electron microscope (SEM) have only to a certain degree been exploited in the study of pathological hair fibers. In this review brief viewpoints on aspects of preparation and interpretation are discussed. It is shown that SEM will reveal important facts on the morphology of pathological hairs is appropriate experiment are performed, such as forming a knot on the fiber. Such a simple experiment will provide information on the fiber cross section, and on the tensile strength of the cuticle and the fiber. Complementary methods for qualitative and quantitative analysis of pathological hair fibers are suggested

Particle Probe Analysis in the Study of Skin Physiology

The basic function of provide a barrier which the epidermis is will separate the body compartment from the environment thus protecting the organism from excessive loss of water and to hinder the entrance of noxious agents. A continuous renewal of the actual barrier makes it possible to fulfill these requirements. Using particle probe analysis, electron microprobe (EMP) and proton microprobe (PMP) analysis we have demonstrated the feasibility of these techniques in the study of skin physiology. The results reported here have been obtained on quench frozen skin specimens inertly prepared by cryotechniques to produce freeze-dried sections presenting cross sections of the skin. The distribution of Na and K is compatible with the idea that the Na/K pump of the cell membranes is dysfunctional above the basal cell layer. The phosphorus distribution over the epidermal cross section coincides with a previously shown phospholipid distribution. S and mass distributions correspond to the results of the keratin synthesis of the epidermis. Calcium displays a profile over the epidermis which is compatible with recent data obtained on the calcium dependence of the differentiation of epidermal cells in culture. Also this distribution corresponds to recent data obtained by histochemical methods at transmission electron microscope resolution. Zn and Fe have been shown to reside mainly in the basal cell layer of the normal epidermis but are found in high amounts in the outer cell layers of the epidermis in hyperproliferative paralesional psoriasis. The penetration of Ni and Cr (Cr2O72-) through human epidermis was studied in vitro and it was found necessary to employ the PMP for the analysis of these substances due to the low amounts present ( \u3c 100 ppm). It appears that chromate penetrates more readily than nickel at neutral pH

REPLICATION TECHNIQUES FOR DRY AND WET BIOLOGICAL SURFACES

Abstract This overview of replication techniques for light and electron microscopic applications gives a generalized background to past and current approaches. The silicone mould replication techniques, which have the great advantage of being applicable to dry as well as wet surfaces, have proven to be the most successful so far. They are discussed in some detail and a number of practical hints for a successful procedure are given. These techniques have a potential of use in material, biological and even in archaeological sciences, although so far such applications have not attracted much attention

Sodium Lauryl Sulfate Enhances Nickel Penetration Through Guinea-Pig Skin. Studies with Energy Dispersive X-Ray Microanalysis

The effect of sodium lauryl sulphate (SLS), a common ingredient of detergents, on the penetration of nickel through the stratum corneum in the guinea-pig skin model was studied with energy dispersive X-ray microanalysis ( EDX) to evaluate the barrier-damaging properties of this common detergent. The EDX technique allows a simultaneous determination of physiologically important elements, e.g., Na. Mg, P, Cl, K, Ca and S in addition to Ni at each point of measurement in epidermal cell strata. Our results show that SLS reduces the barrier function to Ni-ion penetration of the stratum corneum. In addition we have shown that EDX allows analysis of the influence of different factors involved in nickel penetration through the skin by giving data on the physiological effects on the epidermal cells caused by the applied substances

Recent Advances in X-Ray Microanalysis in Dermatology

Electron microprobe and proton microprobe X-ray analysis can be used in several areas of dermatological research. With a proton probe, the distribution of trace elements in human hair can be determined. In contrast to sulfur, which is homogeneously distributed, calcium, iron, and zinc appear to be non-homogeneously distributed over the hair cross-section. Electron microprobe analysis on freeze-dried cryosections of guinea-pig and human epidermis shows a marked gradient of Na, P and K over the stratum granulosum. In sections of freeze-substituted human skin this gradient is less steep. This difference is likely to be due to a decrease in water content of the epidermis towards the stratum corneum. Electron microprobe analysis of the epidermis can, for analysis of trace elements, be complemented by the proton microprobe. Quantitative agreement between the two techniques can be obtained by the use of a standard. Proton micro probe analysis was used to determine the distribution of Ni or Cr in human epidermis exposed to nickel or chromate ions. Possible differences in water content between the stratum corneum of patients with atopic eczema and normal stratum corneum was investigated in skin freeze- substituted with Br-doped resin. No significant differences were observed. Proliferative reactions in the epidermis appear to be associated with increased levels of the elements P and K. Such changes were found in guinea-pig skin after exposure to sodium lauryl sulfate, and in plaques of skin from patients with psoriasis

Proton-Induced X-Ray Emission Analysis - A New Tool in Quantitative Dermatology

Proton-Induced X-ray emission analysis (PIXE) constitutes a method for trace element analysis characterized by multielemental capability, detection limits in the low ppm-range and size resolution down towards a micrometre. In applications where the sensitivity of the Electron-Induced X-ray Emission (EIXE) analysis is not sufficient and where a spatial resolution not better than a few micrometres is required, the PIXE technique provides a powerful tool. In this paper properties of the PIXE method are demonstrated by quantitative results from three different samples of dermatological interest. Firstly, mercury results from a longitudinal scan of a single hair strand from a mercury poisoned person are shown. With a spatial resolution of one or a few millimetres very fast scans may be performed on hair strands giving information on time and magnitude of intoxication or other exposures, as well as deficiencies. Secondly, results are given from a radial scan with a beam width of 4 micron on hair from a person exposed to high amounts of iron. The calcium, iron and zinc distributions but not the sulphur and potassium distributions show narrow peaks of concentration (less than 4 micron) about 15micron from the surface of the hair. Further investigations have to be performed in order to interpret these data. Thirdly, the depth profiles in skin of some elements were measured with a beam width of 10 micron. The results show significant increases in sulphur, calcium and zinc concentrations and significant decreases in phosphorous and potassium concentrations at the skin surface i.e. in the stratum corneum

Proton and Electron Microprobe Analysis of Human Skin

In order to demonstrate the feasibility of the proton microprobe in the analysis of dermatological material when a spatial resolution of a few micrometres is sufficient and to compare it with the electron microprobe technique, duplicate sections of human skin have been analysed with both methods. A skin sample was obtained from each of three healthy volunteers. After cryosectioning (12 μm) and freeze-drying adjacent sections of each sample were scanned by the electron microprobe and the proton microprobe, respectively

Elemental Analysis on Freeze-Dried Sections of Human Skin: Studies by Electron Microprobe and Particle Induced X-Ray Emission Analysis

The possibility of using the proton microprobe (PMP) in the elemental analysis of dermatological material, under conditions where the spatial resolution can be restricted to a few micrometers, was demonstrated. Comparison with the electron microprobe (EMP) technique using duplicate sections from the same human skin biopsies revealed that the PMP and EMP techniques are complementary and yield closely corresponding elemental distributions for elements of dermatological interest. The concentrations of phosphorus and potassium were low in the dermis, high in the stratum basale and stratum spinosum, and decreased markedly in the stratum granulosum to a low level in the stratum corneum. The sulfur concentration was highest in the stratum corneum