Lack of relationship between Langerhans cells, epidermal cell proliferation and epidermal G1 chalone.

Mouse tail interscale epidermis contains numerous Langerhans cells, whereas the adjacent scale regions are devoid of these cells. No difference in a) proliferative activity and b) inhibitory effect of the epidermal G1 chalone can be demonstrated in both regions. A direct relationship between Langerhans cells and growth control may be excluded.     

The balance between immunity and tolerance: The role of Langerhans cells

Langerhans cells are immature skin-homing dendritic cells that furnish the epidermis with an immune surveillance system, and translate information between the internal and external milieu. Dendritic cells, in particular Langerhans cells, are gaining prominence as one of the potential principal players orchestrating the decision between immunity and tolerance. Langerhans cells capture aberrant self-antigen and pathogen-derived antigen for display to the efferent immune response. Recent evidence suggests redundancy in the antigen-presenting function of Langerhans cells, with dermal dendritic subsets capable of fulfilling an analogous role. There is mounting evidence that Langerhans cells can cross-prime T cells to recognize antigens. Langerhans cells are proposed to stimulate T regulatory cells, and are implicated in the pathogenesis of cutaneous T cell lymphoma.The phenotype of Langerhans cells, which may be tolerogenic or immunogenic, appears to depend on their state of maturity, inciting immunogen and cytokine environment, offering the potential for manipulation in immunotherapy. Received 6 August 2008; received after revision 18 September 2008; accepted 13 October 2008     

Elektronenmikroskopischer nachweis von langerhansschen zellen im epithel normaler menschlicher vagina

Summary Typical Langerhans cells were demonstrated in the normal human vaginal epithel by electron- microscopic means.     

Granules of Langerhans cells in the thymus contain gold

The granules of Langerhans cells in the thymus of the rat were subjected to X-ray microanalysis. It was established that gold is present in these morphological structures.     

Granules of langerhans cells in the thymus contain gold

Summary The granules of Langerhans cells in the thymus of the rat were subjected to X-ray microanalysis. It was established that gold is present in these morphological structures.     

Die licht- und sublichtmikroskopische Morphologie der Epidermis des neotenen Axolotls (Siredon mexicanum Shaw)

Summary Three different cell types are the most frequent elements of the epidermis of the neotenic axolotl: (1) the common epidermal cells are small and multiform. They show bundles of tonofilaments (figures ofEberth) in the stratum basale. (2) The big Leydig cells contain numerous gross granules and a special network in the peripheral cytoplasm (Langerhans net). (3) The cover cells forming the outer layer of the epidermis possess a striking mucin zone in the apical cytoplasm.     

Persistance of endocrine cells in immuno-induced carcinoma of the exocrine pancreas: insulin, glucagon, and somatostatin cells]

In immuno-induced exocrine pancreatic carcinomas, which keep their exocrine secretory specificity through their different evolution stages [(1), (2)], normal B, A and D endocrine cells are still found, demonstrated by immunochemical techniques. They are localized in the islets of Langerhans. B and A cells are scattered in adenomatous pancreatic remains, and in the anaplasic carcinoma; D cells are found in the ductular and adenomatous remains. The three types of endocrine secretion granules are analyzed by electron microscopy at the early and late stages of carcinogenesis. The origin of the persisting endocrine cells and the nature of undifferentiated cells proliferating from the ductular epithelium are discussed.     

N-acetylglucosaminyltransferase V modifies the signaling pathway of epidermal growth factor receptor

Transfection of sense cDNA of N-acetylglucosamyltransferase V (GnTV-S) into human H7721 hepatocarcinoma cells resulted in an increase in the N-acetylglucosamine1,6mannose1,3- branch (GnT-V product) on the N-glycans of epidermal growth factor (EGF) receptor (EGFR), and promotion of its EGF binding and tyrosine autophosphorylation, but showed little effect on the expression of EGFR protein. The phosphorylation at T308, S473 and tyrosine residue(s) and the activity of protein kinase B (Akt/PKB) as well as the phosphorylation of p42/44 mitogen-activated protein kinase (MAPK) and MAPK kinase (MEK) before and after EGF stimulation were concomitantly increased. Conversely, in the antisense GnT-V (GnTV-AS)-transfected H7721 cells, all the results were the reverse of those with GnTV-S-transfected cells. After the cells were treated with 1-deoxymannojirimycin, an inhibitor of N-glycan processing at high mannose, or antibody against the extracellular glycan domain of EGFR, the differences in PKB activity, p42/44 MAPK and MEK phosphorylation among GnTV-S-, GnTV-AS- and mock-transfected cells were significantly attenuated. These findings indicate that the altered expression of GnT-V will change the glycan structure and function of EGFR, which may modify downstream signal transduction.Received 24 March 2004; received after revision 1 May 2004; accepted 25 May 2004     

Chalone regulation of the epidermal cell cycle.

Purified epidermal G2 chalone does not inhibit DNA synthesis or influx of S-phase cells and is therefore cell cycle phase-specific, inhibiting only the flow of cells into M-phase.     

Primary culture of dispersed skin epidermal cells of rainbow trout Oncorhynchus mykiss Walbaum

This is the first report on a primary culture of dispersed skin epidermal cells of rainbow trout Oncorhynchus mykiss Walbaum. These primary cells revealed a low seeding efficiency after 3 days (11.6 ± 4.6%), whereas subcultured cells had a higher seeding efficiency at the same time point (75.5 ± 34.0%) and increased in cell number (150 – 200% of seeded cells after 20 to 30 days). The cells were characterized applying histological, immunocytochemical and ultrastructural methods. The culture consisted of undifferentiated keratinocytes. Mucous cells as well as differentiated epithelial cells were absent. To date the cells were cultured for maximally 9 passages and 402 days and therefore provide the possibility for long-term studies. Received 31 March 1998; received after revision 14 July 1998; accepted 14 July 1998     

Isolation of human epidermal stem cells by adherence and the reconstruction of skin equivalents

The isolation of human epidermal stem cells is critical for their clinical applications. In the present study, we isolated three populations of epidermal keratinocytes according to their ability to adhere to collagen type IV: i.e., rapidly adhering (RA), slowly adhering (SA), and non-adhering (NA) cells. The aim of this study was to characterize RA cells and to investigate the possibility of using these cells for epidermis reconstruction. To identify RA cells, flow cytometric analysis was performed using anti-₆ integrin and anti-CD71 antibodies. RA cells express high levels of ₆ integrin and low levels of CD71, which are considered as markers of an epidermal stem cell nature. Furthermore, electron microscopy showed that RA cells are small and have a high nuclear to cytoplasmic ratio, whereas SA and NA cells have well-developed cellular organelles and abundant tonofilaments. Western blot analysis showed that RA cells are slow cycling and express p63, a putative epidermal stem cell marker, whereas SA and NA cells express c-Myc, which is known to regulate stem cell fate. To compare epidermal regenerative abilities, skin equivalents (SEs) were made using RA, SA, and NA cells. The epidermis constructed from RA cells was well formed compared to those formed from SA or NA cells. In addition, only SEs with RA cells expressed ₆ integrin and ₁ integrin at the basal layer. These results indicate that RA cells represent epidermal stem cells and are predominately comprised of stem cells. Therefore, the isolation of RA cells using a simple technique offers a potential route to their clinical application, because they are easily isolated and provide a high yield of epidermal stem cells.Received 2 July 2004; received after revision 20 August 2004; accepted 10 September 2004     

Current cases in which epitope mimicry is considered as a component cause of autoimmune disease: immune-mediated (type 1) diabetes

Autoimmune diseases result from a combination of genetic, immunologic, hormonal, and environmental factors. Infectious agents may induce the breakdown of immunological tolerance and the appearance of autoreactivity. However, the specific relationship between infection and autoimmunity is still unclear. One of the mechanisms responsible could be molecular mimicry between the infectious agent and self. The concept of molecular mimicry is a viable hypothesis in the investigation of the etiology, pathogenesis, treatment, and prevention of autoimmune disorders. Immune-mediated (type 1) diabetes in humans and in non-obese diabetic (NOD) mice is polygenic and characterized by autoimmune destruction of insulin-producing pancreatic beta cells in islets of Langerhans. In NOD mice, a T-helper 1 (Th1)-based autoimmune response arises spontaneously against glutamate decarboxylase (GAD) concurrently with the onset of insulitis. Subsequently. this Th1-type autoreactivity spreads intra- and intermolecularly to other beta cell autoantigens, suggesting that a Th1-type response is responsible for the progression of the disease, whereas Th2 responses when experimentally induced are protective. In humans, a homology between GAD and the P2-C protein of Coxsackie B make a cause-and-effect molecular mimicry an attractive hypothesis. Evidence to support the concept of molecular mimicry in diabetes is reviewed.     

Stimulation of peripheral guinea pig blood lymphocytes by autologous epidermal cells]

Using a strictly autologous (and not syngeneic) mixed culture system in the guinea-pig, it was shown that Mitomycin C treated ear epidermal cells (E) were capable of stimulating peripheral blood lymphocytes (L) from the same animal. The proliferative response of the lymphocytes as measured by 3H thymidine incorporation, is optimal on the 5th day of culture, and when the ratio of the concentrations of the two cell populations (L : E) is 1 : 1. The autoreactivity of the lymphocytes varies with the animal.     

Possible target of Abelson virus phosphokinase in cell transformation

By fusing interphase cells to cells undergoing mitosis, the interphase chromosomes can be visualized. When analyzed in this way, chromosomes of normal mouse cells show characteristic undercondensed centromeric regions. We have found that the centromeric regions of chromosomes from Abelson virus-transformed cells are fully condensed. Abelson virus transforms mouse cells by introducing into them a virally encoded phosphokinase that is expressed constitutively. Thus, we propose that the condensation of centromeric chromatin is a result of overphosphorylation by the Abelson virus phosphokinase, and that the centromeric region is the relevant target of overphosphorylation in transformed cell growth.     

Very large common fragile site genes and their potential role in cancer development

Common fragile sites (CFSs) are large chromosomal regions that are hot-spots for alterations especially within cancer cells. The three most frequently expressed CFS regions (FRA3B, FRA16D and FRA6E) contain genes that span extremely large genomic regions (FHIT, WWOX and PARK2, respectively), and these genes were found to function as important tumor suppressors. Many other CFS regions contain extremely large genes that are also targets of alterations in multiple cancers, but none have yet been demonstrated to function as tumor suppressors. The loss of expression of just FHIT or WWOX has been found to be associated with a worse overall clinical outcome. Studies in different cancers have revealed that some cancers have decreased expression of multiple large CFS genes. This loss of expression could have a profound phenotypic effect on these cells. In this review, we will summarize the known large common fragile site genes and discuss their potential relationship to cancer development.     

Erythrocytes within pancreatic B-cells of corticosteroid-treated mice.

An ultrastructural study of the endocrine pancreas of female ICR mice that received 21 daily injections of the synthetic glucocorticoid, Triamcinolone diacetate (8 mg/kg b.wt) revealed some examples of microhaemorrhage within islets of Langerhans, extravasation of erythrocytes, and the presence of erythrocytes within B-cells, where they undergo degradation to form myelin-like configurations.     

Erthrocytes within pancreatic B-cells of corticosteroid-treated mice

Summary An ultrastructural study of the endocrine pancreas of female ICR mice that received 21 daily injections of the synthetic glucocorticoid, Triamcinolone diacetate (8 mg/kg b. wt) revealed some examples of microhaemorrhage within islets of Langerhans, extravasation of erythrocytes, and the presence of erythrocytes within B-cells, where they undergo degradation to form myelin-like configurations.     

Injury-induced neurogenesis in the mammalian forebrain

It has been accepted that new neurons are added to the olfactory bulb and the hippocampal dentate gyrus throughout life in the healthy adult mammalian brain. Recent studies have clarified that brain insult raises the proliferation of neural stem cells/neural progenitor cells existing in the subventricular zone and the subgranular zone, which become sources of new neurons for the olfactory bulb and the dentate gyrus, respectively. Interestingly, convincing data has shown that brain insult invokes neurogenesis in various brain regions, such as the hippocampal cornu ammonis region, striatum, and cortex. These reports suggest that neural stem cells/neural progenitor cells, which can be activated by brain injury, might be broadly located in the adult brain or that new neurons may migrate widely from the neurogenic regions. This review focuses on brain insult-induced neurogenesis in the mammalian forebrain, especially in the neocortex.     

Migratory patterns of clonally related cells in the developing central nervous system

Neurons and glioblasts that arise in the ventricular zone migrate to form discrete nuclei and laminae as the central nervous system develops. By stably labeling precursor cells in the ventricular zone, pathways taken by different cells within an individual clone can be described. We have used recombinant retroviruses to label precursor cells with a heritable marker, the E. coli lacZ gene; clones of lacZ-positive cells are later mapped histochemically. Here we review results from three regions of the chicken central nervous system--the optic tectum, spinal cord, and forebrain--and compare them with previous results from mammalian cortex and other regions of the vertebrate CNS. In particular, we consider the relationship between migratory patterns and functional organization, the existence of multiple cellular sources of migratory guidance, and the issue of whether a cell's choice of migratory pathway influences its ultimate phenotype.