Basal layer

Reported studies have shown its anti-inflammatory effects and anti-oxidant action. It acts by thinning the stratum corneum, promoting epidermolysis, dispersing basal layer melanin and epidermal and dermal hyaluronic acid and collagen gene expression that increases through an elevated secretion of IL-6 [3]. 

Fig. 2.16 Comparison of the fine structure of VNOR (right) with OR (left) cells. A = axon BL = basal layer C = cilia D = dendrite G = golgi GC = glial cell MV = microvilli, PC = primordial (basal) cell SER = smooth endoreticulum. TEM, scale bar 1.0 pm (from Mendoza, 1993).

Schmidt What happens to the six cortical divisions in the p27 deficient mice Likewise, has anyone ever done the heroic thing of taking the basal layer that gives rise to the six cortical divisions and transplanting it down one day to see whether it still has five divisions left ... 

The stratum corneum consists of separated, nonviable, cornified, almost nonpermeable corneocytes embedded into a continuous lipid bilayer made of various classes of lipids, for example, ceramides, cholesterol, cholesterol esters, free fatty acids, and triglycerides [6], Structurally, this epidermis layer is best described by the so-called brick-and-mortar model [7], The stratum corneum is crucial for the barrier function of the skin, controlling percutaneous absorption of dermally applied substances and regulating fluid homeostasis. The thickness of the stratum corneum is usually 10-25 /an, with exceptions at the soles of the feet and the palms, and swells several-fold when hydrated. All components of the stratum corneum originate from the basal layer of the epidermis, the stratum germinativum. 

The basement membrane (BM) is a continuous layer of extracellular materials, forming a boundary between the basal layer of the epithelium and the connective tissues of the lamina propria and the submucosa. It can be subdivided into the lamina lucida,... 

Effects on the skin were observed in rats treated dermally with 40 mg nickel/kg/day as nickel sulfate for 15 or 30 days (Mathur et al. 1977). The effects included distortion of the epidermis and dermis after 15 days and hyperkeratinization, vacuolization, hydropic degeneration of the basal layer, and atrophy of the epidermis at 30 days. Biochemical changes in the skin (enzymatic changes, increased lipid peroxidation, and an increase in the content of sulfhydryl groups and amino nitrogen) were observed in... 

Sensations of irritation, pain and temperature, commonly referred to as trigeminal responses, are also experienced in the nose. Typically strong stimulants include CO2, menthol, ammonia and acids however, most odorants do have some chemesthetic component They have shorter response latencies than in the oral cavity, consistent with a shorter distance required to penetrate to the basal layer containing die nerve endings the stimulants also increase in intensity with repeated exposures (sniffs) (28), Irritants reduce the intensity of odorants the reverse is also true. The interaction is at the central processing level because an odorant presented in one nostril will be affected by an irritant given in the other nostril. 

The mechanism of the scaling of iron is so complex as to require special mention. Above 570 °C, wiistite (Fei xO) is thermodynamically stable and forms the relatively thick basal layer in the oxide film. This is followed by a magnetite (FesCU) layer which is followed by a final layer of Fe2C>3. Magnetite itself tends to become nonstoichiometric under oxidizing conditions, with excess Fe3+, so that its composition and color can vary from Fe3.oooC>4 (black) toward cubic Fe2.667 04 (i.e., 7-Fe203, chocolate brown). Thus, as outlined in Section 4.6, the oxidation of iron above 570 °C involves mainly... 

The composition of the Stassfurt salt beds.—The deposits about Stassfurt may very roughly be grouped in a series of strata indicated in Fig. I.13 Starting from a basal layer of anhydrite and gypsum there are ... 

The inner layer of the corneal stroma is a dense membrane of collagen like the basal membrane of the monolayer of corneal endothelium. Descemets membrane is transparent with a thickness varying from 7 to 20 pm, according to the age of the individual. Conjunctiva and cornea host nerve endings of high density in the snperhcial and basal layers. The cornea at the limbns smoothly changes to sclera with interconnected nontransparent collagen hbrils. 

Santos, M., Perez, P., Segrelles, C., Ruiz, S., Jorcano, J. L., and Paramio, J. M. (2003). Impaired NF-kappa B activation and increased production of tumor necrosis factor alpha in transgenic mice expressing keratin K10 in the basal layer of the epidermis. J. Biol. Chem. 278, 13422-13430. 

Due to the relative ease of oxidation of the parent compound, common delivery forms in cosmetic formulations and clinical trials are vitamin E acetate (a-TAc, structure in Fig. 15.7a) and vitamin E phosphate. These forms are expected to permeate and to regenerate free active a-TH through enzyme-catalyzed hydrolysis activities in skin. Although a-TAc is readily hydrolyzed by esterase action to vitamin E upon oral ingestion, no consensus as to the extent of bioconversion of topically applied a-TAc has been reached. Two published studies demonstrate bioconversion up to 10-15% in the viable epidermis [35] including the basal layer [36]. These and other studies show no detectable metabolism of a-TAc in stratum corneum [37]. 

---