Telomere Length Differences upon Keratinization and its Variations in Normal Human Epidermal Keratinocytes
Issue:
Volume 2, Issue 4, July 2014
Pages:
28-35
Received:
20 August 2014
Accepted:
6 September 2014
Published:
20 September 2014
Abstract: Telomeres are the physical ends of chromosomes, and are cleaved with each cell division. Telomere loss results from not only incomplete DNA replication (“end replication problem”), followed by the processing of chromosome, but also exposure to various DNA damaging agents. Human epidermis is constantly replaced through replication at the basal layer, followed by upward movement and terminal differentiation at the suprabasal layer. The objective of this study was to assess differences in telomere length between basal and suprabasal keratinocytes, and variations of telomere lengths among basal cells. We investigated terminal restriction fragment (TRF) length in fractions of epidermal cells by Southern blot analysis. Time-dependent trypsin treatment to epidermis divided into basal cell rich and suprabasal cell rich fractions. In the five skin samples from various sites of the body, the mean TRF length were 5,932 ± 470 (range 5,182-6,630) bp in basal cell rich fraction showing 21.5% ± 5.8% (range 12.6-28.6%) of keratin 10 (K10)-positivity, which is marker of keratinizing suprabasal cell, and 5,320 ± 640 (range 4,495-6,212) bp in suprabasal cell rich fraction showing 78.8% ± 4.0% (range 72.8-83.0%) of K10-positivity. It was calculated that K10 positive cells have 1,091 ± 963 (range 248-2,650) bp shorter telomeres compared to K10 negative cells. In addition, fluorescence in situ hybridization (FISH) study showed that columnar groups of keratinocytes with statistically longer telomere in each nucleus than the other epidermal cells in the vicinity occupied occasionally between the tip of dermal papilla and the bottom of rete ridge. The present study showed that the keratinizing suprabasal cells have shorter telomeres compared to basal cells. FISH study showed that some groups of epidermal cells having different replicative histories among the groups of epidermal cells in the vicinity.
Abstract: Telomeres are the physical ends of chromosomes, and are cleaved with each cell division. Telomere loss results from not only incomplete DNA replication (“end replication problem”), followed by the processing of chromosome, but also exposure to various DNA damaging agents. Human epidermis is constantly replaced through replication at the basal layer...
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Acute Oral Coumestrol Treatment Induces Sperm and Sex Steroid Alterations in Mice
Hector Serrano,
Guillermo Mora-Ramiro,
Sheila Peña-Corona,
Pablo León-Ortíz,
Arturo Salame-Mendez,
Enrique Mendieta-Márques,
José Luis Gómez-Olivares,
María Dolores García-Suárez
Issue:
Volume 2, Issue 4, July 2014
Pages:
36-40
Received:
8 September 2014
Accepted:
20 September 2014
Published:
30 September 2014
Abstract: Plant phytoestrogens interfere with normal estrogen-regulated functions like steroid synthesis and gonad physiology and morphology. Much evidence has been obtained by using high dose treatments or in vitro exposure to phytoestrogens but little is known about low, dietary level concentrations of these compounds, particularly coumestrol. In order to explore the possible effects on gonads and serum progesterone of oral 10, 20 or 40 μg/Kg body weight dose coumestrol were administered to three experimental groups and compared to a vehicle-only control group (n=5 animals per group) for two weeks and a similar period for treatment recovery. After treatment, testes and blood were obtained and processed for testis and sperm morphology alterations, and steroid hormone evaluation, respectively. Coumestrol treatment induces a significant dose-dependent testis volume decrease and a decrease in 17β hydroxysteroid dehydrogenase activity causing a progesterone increase in response to phytoestrogen concentration. These alterations impair the normal sperm production with an increase in abnormal head and tail shapes. These data strongly suggest a deleterious effect of oral, low concentration phytoestrogen content in adult male diets.
Abstract: Plant phytoestrogens interfere with normal estrogen-regulated functions like steroid synthesis and gonad physiology and morphology. Much evidence has been obtained by using high dose treatments or in vitro exposure to phytoestrogens but little is known about low, dietary level concentrations of these compounds, particularly coumestrol. In order to ...
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