RESUMEN
OBJECTIVE: The purpose of this study was the evaluation of thiolated silicone oil as novel skin protectant exhibiting prolonged residence time, enhanced barrier function and reinforced occlusivity. METHODS: Two silicone conjugates were synthesized with mercaptopropionic acid (MPA) and thioglycolic acid (TGA) as thiol ligands. Adhesion, protection against artificial urine and water vapour permeability with both a Payne cup set-up and transepidermal water loss (TEWL) measurements on porcine skin were assessed. RESULTS: Silicone thiomers showed pronounced substantivity on skin with 22.1 ± 6.3% and 39.2 ± 6.7% remaining silicone after 8 h for silicone-TGA and silicone-MPA, respectively, whereas unmodified silicone oil and dimethicone were no longer detectable. In particular, silicone-MPA provided a protective shield against artificial urine penetration with less than 25% leakage within 6 h. An up to 2.5-fold improved water vapour impermeability for silicone-MPA in comparison with unmodified control was discovered with the Payne cup model. In addition, for silicone-MPA a reduced TEWL by two-thirds corresponding to non-thiolated control was determined for up to 8 h. CONCLUSION: Thiolation of silicone oil leads to enhanced skin adhesiveness and barrier function, which is a major advantage compared to commonly used silicones and might thus be a promising treatment modality for various topical applications.
Asunto(s)
Aceites de Silicona/química , Piel/efectos de los fármacos , Compuestos de Sulfhidrilo/química , Agua Corporal , Permeabilidad , Aceites de Silicona/farmacología , Piel/metabolismo , Compuestos de Sulfhidrilo/farmacologíaRESUMEN
A screening assay based on real-time PCR and melt curve analysis was developed to detect DNA from nine common European animal families/species and human. The assay consists of a 10-cycle universal pre-amplification followed by specific nested PCR and was designed to exploit the different melting temperatures (T m) of family/species-specific 12S ribosomal ribonucleic acid and cytochrome b fragments, which are amplified in duplex reactions. Case-related modular application is possible. Beyond determination of the animal family and discrimination from human DNA, evaluation of the melt curve in some cases additionally allows for species determination (e.g. cat vs. lynx). The method presents a quick, flexible and sample-saving approach to assess non-human DNA at low expenses, and it is especially useful in resolution of DNA mixtures.
Asunto(s)
Animales Domésticos/genética , Animales Salvajes/genética , Citocromos b/genética , Genética Forense/métodos , Tamizaje Masivo/métodos , ARN Ribosómico/genética , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Especificidad de la Especie , Animales , ADN Mitocondrial/genética , Humanos , Lynx/genéticaRESUMEN
The segregation of mitochondrial genomes and the inheritance of mitochondrial DNA are constant matters of debate. To obtain more information about this issue and to answer the question whether or not it is possible to distinguish mitochondrial DNA (mtDNA) samples from monozygous individuals by analysing heteroplasmic length variants, 290 monozygous and 121 dizygous twin pairs and 34 sets of multiples were studied by RFLP and partly by direct sequencing. A factor D describing the respective pattern of length variants in a given sample was also calculated. The results show that monozygous individuals exhibit a significantly lower median and closer distribution of D than non-monozygous siblings. Thus, a differentiation of mtDNA samples from monozygous twins by this trait is not possible. The high percentage of heteroplasmic individuals, the low median of the D values and the unexpectedly very similar distribution of length variants in monozygotic individuals support the existence of a relatively wide bottleneck or the assumption of a regeneration of length heteroplasmy following a tight bottleneck and agree with a random segregation of mtDNA genomes in dividing oocytes.
Asunto(s)
ADN Mitocondrial/genética , Gemelos Monocigóticos/genética , Variación Genética , Humanos , Reacción en Cadena de la Polimerasa , Análisis de Secuencia de ADN , HermanosRESUMEN
Artificial recombination of two or more mitochondrial DNA fragments from different samples would constitute a serious cause of error in forensic DNA typing, and yet one can demonstrate that such events have happened in the preparation of several published mtDNA databases. Focussed database searches, phylogenetic analysis, and network representations can highlight mosaic patterns and thus pinpoint sample mix-up. Therefore, we suggest that this approach should be applied to data prior to publication in order to uncover such errors in time.
