Can shed snakeskin be considered to be a model membrane for human stratum corneum?

Recently there has been some interest in the use of shed snake skin as a "model" membrane for in vitro diffusion studies. Many different species of snake have been utilised as well as different skin sites (dorsal and ventral). The species is usually named and sometimes the skin site is indicated butsometimes neither species nor skin site is reported. Insome countries it is particularly difficult to obtain human skin for in vitro experimentation and it is therefore important to have alternate biological or synthetic membranes which mimic human skin membranes for diffusion experiments. In South Africa. shed snake skin is easily obtainable from the many snake parks present in the country. Since snakes moult periodically, a single animal can provide repeated sheds, thus reducing interindividual variability. Skins can be obtained without injury to the animal and do not have to be subjected to chemical or heat stress prior to use. The epidermis is shed as a large intact sheet, thus a single snake skin can provide multiple samples. Shed snake skin is not a living tissue, can be stored for long periods at room temperature and is easily transported. Stored and fresh snake skins appear to show no differences in permeability. Since snake skin lacks hair follicles,the problems associated with the transfollicular route of penetration, which may be significant in mammalian skins, can be avoided

In vitro permeation of progesterone from a gel through the shed skin of three different snake species

The in vitro diffusion of progesterone from a gel formulation using the European Pharmacopoeia method for transdermal dosage forms is described. The membranes used were the dorsal and ventral portions of the shed skin of three different species of snake. Considerable differences are apparent between the dorsal and ventral sites and between the different species of snake. The dorsal area shows better permeability for progesterone and the permeability order for the different species is python>cobra>viper. These differences may be due to the thickness of the skin and the hinge:scale ratio. The results indicate that shed snake skin is not a model membrane for human skin

Effects of Globularia alypum L. on the gastrointestinal tract

ABSTRACT The effect of Globularia alypum L. leaf aqueous extract was studied on the guinea pig isolated ileum. It has been shown that Globularia alypum L. aqueous extract induces on basal tone guinea pig isolated ileum a dose dependent contraction with of a maximal effect of 96.57 ± 1.39% of the response to histamine 10 -6 M. Globularia alypum L.-induced contraction was demonstrated to be induced by acetylcholine, histamine and arachidonic derivatives. The order of potency of the recorded antagonism was: acetylcholine > histamine > arachidonic acid derivatives. It has also been shown by charcoal meal test in the rat that Globularia alypum L. induces an increment of intestinal peristalsis that was significant at the dose of 400 mg/kg with a proportion of intestine traversed of 71.68 ± 11.76% (n=10) versus 60.69 ± 8.55% (n=10) for the control group (P<0.05). Finally, Globularia alypum L. was shown to exert an anti-ulcer activity against the gastric mucosal damages caused by indomethacin that the mechanism of action may result from an inhibition of intraepithelial lymphocytes migration

Biopolymer-based structuring of liquid oil into soft solids and oleogels using water-continuous emulsions as templates

Physical trapping of a hydrophobic liquid oil in a matrix of water-soluble biopolymers was achieved using a facile two-step process by first formulating a surfactant-free oil-in-water emulsion stabilized by biopolymers (a protein and a polysaccharide) followed by complete removal of the water phase (by either high- or low-temperature drying of the emulsion) resulting in structured solid systems containing a high concentration of liquid oil (above 97 wt %). The microstructure of these systems was revealed by confocal and cryo-scanning electron microscopy, and the effect of biopolymer concentrations on the consistency of emulsions as well as the dried product was evaluated using a combination of small-amplitude oscillatory shear rheometry and large deformation fracture studies. The oleogel prepared by shearing the dried product showed a high gel strength as well as a certain degree of thixotropic recovery even at high temperatures. Moreover, the reversibility of the process was demonstrated by shearing the dried product in the presence of water to obtain reconstituted emulsions with rheological properties comparable to those of the fresh emulsion

Registro da opiliofauna em remanescente florestal no estado do Acre.

Os opiliões são aracnídeos inofensivos que participam dos processos ecológicos de ciclagem de nutrientes e decomposição da matéria orgânica, sendo componentes importantes da fauna edáfica, embora, pobremente conhecidos e estudados, principalmente na região amazônica. Este estudo teve como objetivo conhecer a fauna de opiliões presente em um remanescente florestal, localizado no município de Plácido de Castro, AC, no período de agosto de 2014 a agosto de 2015. Para o levantamento foram utilizados dois métodos de coleta: armadilhas pitfall (coleta passiva) e procura livre noturna (coleta ativa). Pelo método de coleta ativa foi capturado um total de 18 opiliões pertencentes às famílias Cosmetidae, Sclerosomatidae e Manaosbiidae, não sendo coletado nenhum espécime pelo método de coleta passiva. A espécie Paraprotus quadripunctatus e os gêneros Geaya e Cynorta foram registrados pela primeira vez no estado do Acre. Ainda, demonstrou-se que o método de coleta ativa "procura livre noturna" é o mais adequado para a realização deste tipo de estudo

Técnicas no invasivas para el estudio de nuevas formas de administración de fármacos

Antes de escribir este trabajo el primer problema fue establecer una definición precisa de la expresión «no invasiva». Según el diccionario, se puede ver que la «invasión» es una entrada violenta en un país o en el cuerpo. Es así como normalmente se deben presentar los métodos in vitro para el estudio de las nuevas formas de administración. Sin embargo, no es eso lo que la gente espera. Se considera las técnicas no invasivas como «técnicas no violentas, no traumatizantes», porque se hacen en seres humanos sanos a quienes se administran las formas farmacéuticas cuyo destino es estudiado directamente in situ. Estas técnicas no presentan peligro para el voluntario, no son violentas y además tienen una gran sensibilidad ya que durante el trabajo se puede tomar muchas muestras, y emplear dispositivos para facilitar la observación directa.Antes de escribir este trabajo el primer problema fue establecer una definición precisa de la expresión «no invasiva». Según el diccionario, se puede ver que la «invasión» es una entrada violenta en un país o en el cuerpo. Es así como normalmente se deben presentar los métodos in vitro para el estudio de las nuevas formas de administración. Sin embargo, no es eso lo que la gente espera. Se considera las técnicas no invasivas como «técnicas no violentas, no traumatizantes», porque se hacen en seres humanos sanos a quienes se administran las formas farmacéuticas cuyo destino es estudiado directamente in situ. Estas técnicas no presentan peligro para el voluntario, no son violentas y además tienen una gran sensibilidad ya que durante el trabajo se puede tomar muchas muestras, y emplear dispositivos para facilitar la observación directa