Exogenous and endogenous lipids of human hair.

PURPOSE: The aim of this study was to characterize the external and internal lipids of Caucasian hair and their influence in different hair properties such as moisture content, hydrophobic character, and mechanical properties. METHODS: Lipid extraction and their analysis by thin layer chromatography with flame ionization detector were carried out. Lipid rearrangement and water sorption and desorption evaluation of these fibers with and without lipids will also be determined using different techniques such as differential scanning calorimetry, thermogravimetric analysis and dynamic vapor sorption, mainly to evaluate permeation changes of these hair fibers possibly related to the fluidity of the lipids extracted. RESULTS: Caucasian fibers were found to be well hydrated, and moisture diminution was observed mainly for the external lipid extracted fibers. Unexpectedly, the lipid extraction promoted an increase in the break tenacity of the Caucasian fibers. The hydrophobic character of the fiber surfaces indicates the marked hydrophobicity of all fibers. Delipidization promotes only a slight diminution of their hydrophobic properties. Water uptake and desorption studies indicate an important water regain for Caucasian fibers. The external extracted hair fibers presented a diminution of maximum water regain, which surprisingly increases with the following internal lipid extraction. This can be due to a higher water desorption found only for external extracted fibers. CONCLUSIONS: The relationship between fluidity of lipids extracted and hair fiber water diffusion were established. Extraction of internal lipids of Caucasian fibers, which have a higher unsaturated lipid content than external lipids of the same hair fiber, leads to a lower water permeability of the fiber. On the capillar formulations should be considered the importance of lipid fluidity to modify the permeability of the fiber.

The influence of hair lipids in ethnic hair properties.

OBJECTIVE: Biochemical studies have mainly focused on the composition of hair. African hair exhibited lower moisturization and less radial swelling when flushing with water compared with Asian or Caucasian hair, and they assumed a possible lipid differentiation among human populations. This study consists in the lipid characterization of different ethnic hairs (Caucasian, Asian and African hairs) and the influence of these lipids in different hair properties such as humidity and mechanical properties. Evaluation of water sorption and desorption of the different ethnic hairs and with and without lipids is also studied mainly to determine permeation changes of the keratin fibres. METHODS: Extractions of exogenous and endogenous lipids with different organic solvents were performed; lipid analysis and its quantification using thin-layer chromatography coupled to an automated flame ionization detector (TLC/FID) were performed. Absorption and desorption curves were obtained in a thermogravimetric balance equipped with a controlled humidity chamber, the Q5000SA Sorption Analyzer (TA Instruments, New Castle, IL, U.S.A.). Also, mechanical properties (breaking stress and breaking elongation) were analysed using a computer programmable dynamometer (Instron 5500R). RESULTS: Lipid extraction showed the highest amount of total lipids for the African hair which may come from external sebaceous lipids compared with Asian or Caucasian hair. Caucasian fibres were found to be the most hydrated fibre, and a decrease in moisture was found in the extracted fibres, again, which is more important for the Caucasian hair. A superior lineal mass was found for the Asian fibres which supported their higher strength. The results obtained from the analysis of the mechanical properties of delipidized fibres indicate a surprising increase in the strength of African and Caucasian fibres. Perhaps this increase in strength could be related to the humidity decrease in lipid-extracted hair fibres. Results of water uptake and desorption indicate that Asian and Caucasian hairs present the lower diffusion coefficients compared with the African ones. At least for the African fibre, an extraction of its lipids that mainly account for apolar lipids ameliorates the fibre structure, decreasing its permeability to water and increasing its tensile strength. CONCLUSION: The ethnic hairs were assessed related to their lipid composition, and some differences between them were found in terms of water uptake and mechanical properties.

Proteomic and transcriptomic analysis of rice tranglutaminase and chloroplast-related proteins.

The recently cloned rice transglutaminase gene (tgo) is the second plant transglutaminase identified to date (Campos et al. Plant Sci. 205-206 (2013) 97-110). Similarly to its counterpart in maize (tgz), this rice TGase was localized in the chloroplast, although in this case not exclusively. To further characterise plastidial tgo functionality, proteomic and transcriptomic studies were carried out to identify possible TGO-related proteins. Some LHCII antenna proteins were identified as TGO related using an in vitro proteomic approach, as well as ATPase and some PSII core proteins by mass spectrometry. To study the relationship between TGO and other plastidial proteins, a transcriptomic in vivo Dynamic Array (Fluidigm™) was used to analyse the mRNA expression of 30 plastidial genes with respect to that of tgo, in rice plants subjected to different periods of continuous illumination. The results indicated a gene-dependent tendency in the expression pattern that was related to tgo expression and to the illumination cycle. For certain genes, including tgo, significant differences between treatments, principally at the initiation and/or at the end of the illumination period, connected with the day/night cycling of gene expression, were observed. The tgo expression was especially related to plastidial proteins involved in photoprotection and the thylakoid electrochemical gradient.

Determination of maternal-fetal biomarkers of prenatal exposure to ethanol: a review.

The deleterious effects exerted by prenatal ethanol exposure include physical, mental, behavioural and/or learning disabilities that are included in the term fetal alcohol spectrum disorder (FASD). Objective assessment of exposure to ethanol at both prenatal and postnatal stages is essential for early prevention and intervention. Since pregnant women tend to underreport alcohol drinking by questionnaires, a number of biological markers have been proposed and evaluated for their capability to highlight gestational drinking behaviour. These biomarkers include classical biomarkers (albeit indirect) of alcohol-induced pathology (mean corpuscular volume (MCV), gamma glutamyltransferase (GGT), aspartate aminotransferase (AST) and alanine aminotransferase (ALT)) acetaldehyde-derived conjugates, and finally derivatives of non-oxidative ethanol metabolism (fatty acid ethyl esters (FAEEs), ethyl glucuronide (EtG), ethyl sulphate (EtS) and phosphaditylethanol (PEth)). Since ethanol itself and acetaldehyde are only measured few hours after ethanol intake in conventional matrices such as blood, urine and sweat, they are only useful to detect recent ethanol exposure. In the past few years, the non-oxidative ethanol metabolites have received increasing attention because of their specificity and in some case wide time-window of detection in non-conventional matrices from the pregnant mother (oral fluid and hair) and fetus-newborn (neonatal hair, meconium, placenta and umbilical cord). This article reviews bioanalytical procedures for the determination of these markers of ethanol consumption during pregnancy and related prenatal exposure. In addition, clinical toxicological applications of these procedures are presented and discussed.

[Validity of a maternal alcohol consumption questionnaire in detecting prenatal exposure]. / Validez del cuestionario de consumo materno de alcohol para detectar la exposición prenatal.

INTRODUCTION: Ethanol consumption by pregnant women can produce severe effects in the foetus and the newborn, mainly in neurological and weight-height development, and are included in the term FASD (Fetal Alcohol Spectrum Disorder). Questionnaires are the most used screening method to detect prenatal exposure, but a previous population study questioned its reliability. The objective of this study was to compare alcohol prenatal exposure detection by questionnaire compared with biomarkers in meconium. METHODOLOGY: Sixty two meconium samples from mothers who denied alcohol consumption during pregnancy by questionnaire were analysed. The objective analysis was made by determination of FAEEs (fatty acid ethyl esters) as exposure biomarkers in meconium as biological matrix. RESULTS: In the meconium from 10 of 62 newborns from non-alcohol consuming mothers by questionnaire (16.12%) FAEE values were positive (≥ 2 nmol/g). DISCUSSION: Questionnaires as a screening method during pregnancy are not a reliable tool. It is necessary to identify prenatal exposure to alcohol as soon as possible by biomarkers analysis in biological matrices from the newborn or the mother. The early detection will allow these patients to benefit from follow up and treatment to reach the best possible neurological development.

Influence of dietary fat source, alpha-tocopherol, and ascorbic acid supplementation on sensory quality of dark chicken meat.

We studied the influence of dietary fat source and dl-alpha-tocopheryl acetate and ascorbic acid supplementation on the sensory quality of cooked dark chicken meat stored at -20 C for different periods. Results showed that dietary fat source and alpha-tocopheryl acetate supplementation influenced sensory scores (rancid flavor and aroma and acceptability). Ascorbic acid had no influence on these scores. Thiobarbituric acid values showed a high correlation with sensory scores. In addition, the low levels of alpha-tocopheryl acetate contained in the trace mineral-vitamin mix (20 IU/kg of feed) were enough to prevent rancidity development in cooked dark chicken meat when broilers were fed a saturated fat diet and samples were vacuum-packed and stored at -20 C for 13 mo.