Search results for "Dermis"

DNA Content and Synthesis in Several Tissues and Variation of Moulting Hormone-Level in Gryllus bimaculatus DEG (Ensifera, Insecta)

1983

The mode of growth of several tissues in Gryllus bimaculatus was investigated during postembryonic development by cytophotometric methods. In contrast to the situation in holo- metabolous insects, the tissues growing by endomitosis reach only moderate levels of polyploidy. In this case the growth of tissues is achieved by mitotic divisions of small cells with subsequent polyploidization. The time courses of DNA synthesis were measured within the 3rd and, for comparison, the 8th larval instar by incorporation of labelled thymidine followed by autoradiography. Hemocytes, cells of the regeneration crypts of the midgut, gonads and nervous tissue showed a continuous incorporation rate; by contra…

Unmixing of human skin optical reflectance maps by Non-negative Matrix Factorization algorithm

2013

International audience; We present in this paper the decomposition of human skin absorption spectra with a Non-negative Matrix Factorization method. In doing so, we are able to quantify the relative proportion of the main chromophores present in the epidermis and the dermis. We present experimental results showing that we obtain a good estimate of melanin and hemoglobin concentrations. Our approach has been validated by analyzing the human skin absorption spectra in areas of healthy skin and areas affected by melasma on eight patients.

Cloning of Two Putative Ecdysteroid Receptor Isoforms from Tenebrio Molitor and their Developmental Expression in the Epidermis during Metamorphosis

1997

Using the Drosophila EcR-B1 cDNA as a probe, we have cloned the putative ecdysteroid receptor from the mealworm Tenebrio molitor. We have isolated two cDNAs with different 5' termini that contain a complete open reading frame. These two cDNAs encode two proteins with distinct N-terminal regions corresponding to two isoforms. The coleopteran receptor is obviously related to the ecdysteroid receptor of other insects, but shares only 89% and 61% amino acid identities with the DNA-binding and ligand-binding domains of the Drosophila receptor, respectively. Its expression pattern has been examined in the epidermis during the last larval instar and pupal stage of T. molitor, in correlation with t…

A monoclonal antibody against an adult-specific cuticular protein of Tenebrio molitor (Insecta, Coleoptera)

1989

International audience; To study the sequential expression of the epidermal program in the mealworm Tenebrio molitor, monoclonal antibodies were prepared against the water-soluble proteins from preecdysial adult cuticle. Among the 16 clones obtained, one of them (named K2F6) recognized a 20-kDa antigen, found only in adult extracts but not in the larval or pupal ones, as revealed by immunoblot analysis. Our results strongly suggest an epidermal origin for this protein. The monoclonal antibody K2F6 fails to react with water-soluble proteins from fat body and hemolymph taken during the deposition of the 20-kDa antigen. Electron microscopic immunogold localization of this antigen showed that i…

Casparian Strips in the Leaf Intrastelar Canals of Isoetes duriei Bory, a Mediterranean Terrestrial Species

2000

Abstract Anatomical observations, using light and fluorescence microscopy, were made on leaves of Isoetes duriei to verify the presence of casparian bands around the intrastelar canals. This peculiar anatomical feature, previously reported for some Isoetes species, is confirmed. The possible role of this endodermis-like structure, in the transport of water due to root pressure or in the accumulation of certain metabolites, is discussed in relation to the ecological and anatomical features of the species.

Live imaging of stem cell and progeny behaviour in physiological hair-follicle regeneration

2012

Tissue development and regeneration depend on cell-cell interactions and signals that target stem cells and their immediate progeny. However, the cellular behaviours that lead to a properly regenerated tissue are not well understood. Using a new, non-invasive, intravital two-photon imaging approach we study physiological hair-follicle regeneration over time in live mice. By these means we have monitored the behaviour of epithelial stem cells and their progeny during physiological hair regeneration and addressed how the mesenchyme influences their behaviour. Consistent with earlier studies, stem cells are quiescent during the initial stages of hair regeneration, whereas the progeny are more …

Localization of cytokeratin 10 mRNA in human epidermis using nonradioactive in situ hybridization as a routine method

1998

Tyrosinase Enzyme: 1. An Overview on a Pharmacological Target

2014

The tyrosinase enzyme (EC 1.14.18.1) is an oxidoreductase inside the general enzyme classification and is involved in the oxidation and reduction process in the epidermis. These chemical reactions that the enzyme catalyzes are of principal importance in the melanogenesis process. This process of melanogenesis is related to the melanin formation, a heteropolymer of indolic nature that provides the different tonalities in the skin and helps to the protection from the ultraviolet radiation. However, a pigment overproduction, come up by the action of the tyrosinase, can cause different disorders in the skin related to the hyperpigmentation. Several studies mainly focused on the characteristics …

CXCR3-ligand-mediated skin inflammation in cutaneous lichenoid graft-versus-host disease.

2007

Background Lichenoid graft-versus-host disease (liGVHD) histologically shares several common features with other lichenoid dermatoses, such as cutaneous lupus erythematosus and lichen planus (LP), which collectively show a junctional infiltrate of cytotoxic lymphocytes with liquefaction of the basal layer ("interface dermatitis"). Because recent studies have shown a role for type I interferon (IFN)–associated inflammation, including lymphocyte recruitment via CXCR3 ligand interaction in cutaneous lupus erythematosus and LP, we hypothesized that similar mechanisms might also be involved in liGVHD. Methods Ten representative lesional skin biopsies taken from patients with different subsets of…

Expression of Drosophila Cabut during early embryogenesis, dorsal closure and nervous system development.

2010

cabut (cbt) encodes a transcription factor involved in Drosophila dorsal closure (DC), and it is expressed in embryonic epithelial sheets and yolk cell during this process upon activation of the Jun N-terminal kinase (JNK) signaling pathway. Additional studies suggest that cbt may have a role in multiple developmental processes. To analyze Cbt localization through embryogenesis, we generated a Cbt specific antibody that has allowed detecting new Cbt expression patterns. Immunohistochemical analyses on syncytial embryos and S2 cells reveal that Cbt is localized on the surface of mitotic chromosomes at all mitotic phases. During DC, Cbt is expressed in the yolk cell, in epidermal cells and in…