Comparative distribution of sulphur, thiols and disulphides in the porcine stratum corneum.

Biochemical, histochemical and cytochemical analyses were used to determine the sulphur contents and the thiol and disulphide distribution in the stratum corneum (SC) of the wild boar (WB), a large domestic pig breed (DP) and the Goettingen miniature pig (GMP). The sulphur contents (% DW) were different in the three animal types (WB: 1.70-1.38 body, 0.54 ear; DP: 0.84-0.53 body, 0.50 ear; GMP: 2.28-2.51 body, 2.66 ear). The results of the histochemical analysis of SH- and -S-S- groups were clear, and densitometrical extinctions were highest in most body regions of the GMP for thiols and disulphides, followed by the DP for thiols, and the WB for disulphides. Absolute SC thickness was highest in the body of the GMP (62-80 mum), and generally lowest in the ear (20-38 mum) of all animal types. Relative SC thickness was the same for all animals in the body (40-66%), but lower in the ear (30%). Only -S-S- concentrations were correlated with SC thickness, and primarily in the GMP. Cytochemical analysis showed that high sulphur concentrations were obvious particularly in the CCE of corneal cells in the DP, as compared to the cytoplasm. Intracellular sulphur distribution was homogenous in the WB, and in the GMP, although in the latter at a higher concentration level. The results indicate breed-related effects on keratinisation in porcine corneal cells. Only the SC of the outer side of the ear of DP females is recommended as a model for humans.

The porcine ear skin as a model system for the human integument: influence of storage conditions on basic features of epidermis structure and function--a histological and histochemical study.

Based on careful tissue processing, detailed structural analysis, and histochemical as well as cytophotometrical evaluation of the epidermis, the study presents data with respect to changes of tissue integrity during two storing modes (room temperature and 4 degrees C) and various storage times of the porcine auricle. Structural degeneration was first noted in the barrier region of the epidermis from where such changes spread, independent of storage conditions, from small horizontal necrotic islands and continuously with increasing storage time. The histochemical results corroborated these observations, emphasizing, however, that the lower epidermal layers seemed intact for a longer time period than the upper layers. Cytophotometrical evaluation of histochemical stainings showed, with regard to the enzyme succinate dehydrogenase, that oxidative metabolism was negatively affected in the early stages of storage, whereas epidermal lipids (neutral fats, glycolipids) remained relatively stable, even during storage at room temperature. In conclusion, it was obvious that the barrier region is the most sensitive element of the porcine ear epidermis. Taking into consideration that this part of the epidermis is most important for permeation studies, it seems reasonable to avoid any storage of porcine auricles at room temperature, and to use only auricles that have been stored at 4 degrees C for not more than 4 to 6 hours, immediately after delivery from the slaughter-house. In this way better tissue preservation can be achieved, whereby the use of shinkage-free water-soluble plastic embedding would generally improve the histological control of structural integrity, and the application of an easy to handle enzyme histochemical procedure (e.g. succinate dehydrogenase demonstration) to unfixed fresh-frozen sections would help to control basic aspects of tissue functions. The results are discussed in relation to the use of porcine integument as a model in human dermatological research.

[The structure of the skin of the ear in domesticated pigs, with special reference to their use for human dermatological research. 2. Specific histology of the integument]. / Untersuchungen zur Struktur der Ohrhaut beim Hausschwein, unter besonderer Berücksichtigung einer Verwendung in der humandermatologischen Forschung: 2. Spezielle Histologie des Integuments.

Based on light microscopy, the study describes the specific histology of the ear integument of the white domesticated pig. After careful tissue fixation and embedding, routine histological staining, collagen fibre staining, fat demonstration based on frozen sections, and ink injection of the integumental blood vessel system were applied. A detailed description is presented of the structure of the skin layers (epidermis, dermis, hypodermis), the ear cartilage envelopes (fascia, perichondrium), the plica scaphae, the blood vessel distribution, the architecture of the collagen fibre bundles, as well as the hair follicles and the skin glands (sebaceous glands, apocrine tubular glands). The results are discussed with regard to a direct comparison with the histological structure of the human integument, and the advantages and disadvantages of the use of the porcine ear skin as model system in human dermatological research are emphasized.

[The structure of the skin of the ear in domesticated pigs, with special reference to their use for human dermatological research. 1. Macroscopic aspects and hair coat]. / Untersuchungen zur Struktur der Ohrhaut beim Hausschwein, unter besonderer Berücksichtigung einer Verwendung in der humandermatologischen Forschung: 1. Makroskopische Aspekte und Haarkleid.

To begin with, the study describes macroscopically the typical pigmentation, form and surface sculpture of the external ear of the white domesticated pig. Then the palpable stability and elasticity of the ear integument is analyzed, followed by a detailed and microscopically assisted description of the fine relief of the skin surface, the hair line, the hair density, the angle of hair follicle insertion, and the arrangement of hair follicles on both sides of the auricle. The results obtained are discussed with special regard to the use of the porcine ear integument as a model for human skin.

Remarks on the usefulness of toluidine blue staining for RNA cytophotometry in plastic embedded tissues.

The study demonstrates the usefulness of water-soluble plastic resins for the cytological quantification of RNA contents after toluidine blue staining. In this way shrinkage artefacts in delicate tissues are avoided and more exact cytophotometrical results can be obtained from embryological material.