The importance of Merkel cells in the development of human fingerprints.

Human Merkel cells (MCs) were first described by Friedrich S. Merkel in 1875 and named "Tastzellen" (touch cells). Merkel cells are mainly located in the basal layer of the epidermis and are concentrated in touch-sensitive areas. Their density varies among different anatomical sites. Increased concentration was observed in the palms of hands with a predominance in the finger pads and also in the soles and toes. They can be classified according to the function as mechanoreceptive, endocrine, and chemo-sensitive cells. In the development of primary ridges which establish the future fingerprint patterns is assumed that Merkel cells have a significant importance in this process. At about the 7th week EGA, they first time appear in the volar skin and start to occupy the place of future primary ridges at 10 weeks EGA. It will be interesting to study their presence or absence in individuals suffering with abnormal dermatoglyphics and also to study whether the skin diseases associated with altered dermatoglyphics display some deviation regarding the distribution and density of MCs in primary ridges (Fig. 2, Ref. 40). Text in PDF www.elis.sk Keywords: Merkel cells, development, primary ridges, fingerprints, CK-20.

Merkel-like cell distribution in the epithelium of the human vagina. An immunohistochemical and TEM study.

Human Merkel cells (MCs) were first described by Friedrich S. Merkel in 1875 and named "Tastzellen" (touch cells). Merkel cells are primarily localized in the basal layer of the epidermis and concentrated in touch-sensitive areas. In our previous work, we reported on the distribution of MCs in the human esophagus, so therefore we chose other parts of the human body to study them. We selected the human vagina, because it has a similar epithelium as the esophagus and plays very important roles in reproduction and sexual pleasure. Due to the fact that there are very few research studies focusing on the innervation of this region, we decided to investigate the occurrence of MCs in the anterior wall of the vagina. The aim of our research was to identify MCs in the stratified squamous non-keratinized epithelium of the human vagina in 20 patients. For the identification of Merkel cells by light microscopy, we used antibodies against simple-epithelial cytokeratins (especially anti-cytokeratin 20). We also tried to identify them using transmission electron microscopy. Our investigation confirmed that 10 (50 %) of 20 patients had increased number of predominantly intraepithelial CK20 positive "Merkel-like" cells (MLCs) in the human vaginal epithelium. Subepithelial CK20 positive MLCs were observed in only one patient (5%). We tried to identify them also using transmission electron microscopy. Our investigation detected some unique cells that may be MCs. The purpose of vaginal innervation is still unclear. There are no data available concerning the distribution of MCs in the human vagina, so it would be interesting to study the role of MCs in the vaginal epithelium, in the context of innervation and epithelial biology.

The effect of salivary gland extract of Lucilia sericata maggots on human dermal fibroblast proliferation within collagen/hyaluronan membrane in vitro: transmission electron microscopy study.

BACKGROUND: Lucilia sericata maggots are applied to chronic wounds to aid healing when conventional treatments have failed. After their application into a necrotic wound, they potentially influence wound healing with a combination of specific proteinases that are involved in the remodeling of extracellular matrix. These proteases cause changes in fibroblast adhesion and spread upon extracellular matrix protein surfaces, affecting integrity of the protein surfaces-especially fibronectin-while maintaining cell viability. OBJECTIVE: This study focused on in vitro monitoring of the effect of homogenate substances prepared from maggot salivary gland of L sericata on the ultrastructure of human neonatal fibroblasts. METHODS: Collagen/hyaluronan membrane was used as the synthetic substitute of extracellular matrix. The cultured human neonatal fibroblasts B-HNF-1 were seeded on the surface of the collagen/hyaluronan membrane and cultured with maggot salivary gland extract (SGE) at a concentration of 2.4 glands/1 mL. RESULTS: The authors observed increased cell metabolism and protein production (euchromatic nucleus, voluminous nuclear membrane, large reticular nuclei, distended and filled cisterns of rough endoplasmic reticulum, Golgi apparatus with saccules, and vesicles packed with fine fibrillar material) after incubating the cells in culture medium with SGE. CONCLUSION: The authors believe that increased cell metabolism and protein production corresponded with formation of microfibrillar net used for migration of fibroblasts in culture, but mainly for proper production of extracellular matrix. The authors suggest that their results may help explain the effect of SGE on wound healing and support implementation of maggot therapy into human medicine.