Browsing by Subject "Hair"

Now showing 1 - 6 of 6
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    Dermal exosomes containing miR-218-5p promote hair regeneration by regulating β-catenin signaling.
    (Science advances, 2020-07) Hu, Shiqi; Li, Zhenhua; Lutz, Halle; Huang, Ke; Su, Teng; Cores, Jhon; Dinh, Phuong-Uyen Cao; Cheng, Ke
    The progression in the hair follicle cycle from the telogen to the anagen phase is the key to regulating hair regrowth. Dermal papilla (DP) cells support hair growth and regulate the hair cycle. However, they gradually lose key inductive properties upon culture. DP cells can partially restore their capacity to promote hair regrowth after being subjected to spheroid culture. In this study, results revealed that DP spheroids are effective at inducing the progression of the hair follicle cycle from telogen to anagen compared with just DP cell or minoxidil treatment. Because of the importance of paracrine signaling in this process, secretome and exosomes were isolated from DP cell culture, and their therapeutic efficacies were investigated. We demonstrated that miR-218-5p was notably up-regulated in DP spheroid-derived exosomes. Western blot and immunofluorescence imaging were used to demonstrate that DP spheroid-derived exosomes up-regulated β-catenin, promoting the development of hair follicles.
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    Developing Methods for Access to High Quality Genome Sequences from Wild Ape Populations
    (2014-05-07) Koundakjian, Dylan
    Modern evolutionary study of wild ape populations requires the collection of genomic DNA from individuals living in their natural habitat. In order to be maximally useful, these samples must be robust enough for the amplification and subsequent assembly of genomic sequences, which are driving much of modern evolutionary research. Additionally, conservation efforts require that these samples be collected with zero intervention on the study species, because all great apes are now critically endangered. Consequently, the conventional method for genomic DNA collection has been extraction from cells present in fecal samples. However, this approach presents multiple difficulties to investigators, including extensive contamination of sequences from gut microbiota and limited storage time. The purpose of this study is to explore alternative procedures of noninvasive DNA collection to overcome these challenges. Specifically, the study looks at DNA extraction from hair follicle cells and from cells present in urine. These sources of genomic information confer a number of advantages over feces, such as smaller volumes of collection, much lower levels of microbial contamination, and relative ease of storage and transport. In this study, a method for isolating genomic DNA from chimpanzee (Pan troglodytes) hair follicle cells is developed and tested for limit of detection using a decreasing number of hairs per extraction. Validation of the method is then established through the determination of the frequency of polymorphisms due genomic amplification error by comparing sequences obtained from three identically handled samples. After laying out the next steps of development for this method, the study also suggests a similar investigation for samples derived from urine. The overall aim of these studies is a future incorporation of these procedures into the suite of DNA collection techniques available to researchers working with natural populations of great apes and other mammals.
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    Hair cortisol as a biomarker of stress in mindfulness training for smokers.
    (J Altern Complement Med, 2014-08) Goldberg, Simon B; Manley, Alison R; Smith, Stevens S; Greeson, Jeffrey M; Russell, Evan; Van Uum, Stan; Koren, Gideon; Davis, James M
    OBJECTIVES: Stress is a well-known predictor of smoking relapse, and cortisol is a primary biomarker of stress. The current pilot study examined changes in levels of cortisol in hair within the context of two time-intensity matched behavioral smoking cessation treatments: mindfulness training for smokers and a cognitive-behavioral comparison group. PARTICIPANTS: Eighteen participants were recruited from a larger randomized controlled trial of smoking cessation. OUTCOME MEASURES: Hair samples (3 cm) were obtained 1 month after quit attempt, allowing for a retrospective analysis of hair cortisol at preintervention and post-quit attempt time periods. Self-reported negative affect was also assessed before and after treatment. INTERVENTION: Both groups received a 7-week intensive intervention using mindfulness or cognitive-behavioral strategies. RESULTS: Cortisol significantly decreased from baseline to 1 month after quit attempt in the entire sample (d=-0.35; p=.005). In subsequent repeated-measures analysis of variance models, time by group and time by quit status interaction effects were not significant. However, post hoc paired t tests yielded significant pre-post effects among those randomly assigned to the mindfulness condition (d=-0.48; p=.018) and in those abstinent at post-test (d=-0.41; p=.004). Decreased hair cortisol correlated with reduced negative affect (r=.60; p=.011). CONCLUSIONS: These preliminary findings suggest that smoking cessation intervention is associated with decreased hair cortisol levels and that reduced hair cortisol may be specifically associated with mindfulness training and smoking abstinence. RESULTS support the use of hair cortisol as a novel objective biomarker in future research.
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    Probing near-infrared photorelaxation pathways in eumelanins and pheomelanins.
    (J Phys Chem A, 2010-11-04) Piletic, Ivan R; Matthews, Thomas E; Warren, Warren S
    Ultraviolet-visible spectroscopy readily discerns the two types of melanin pigments (eumelanin and pheomelanin), although fundamental details regarding the optical properties and pigment heterogeneity are more difficult to disentangle via analysis of the broad featureless absorption spectrum alone. We employed nonlinear transient absorption spectroscopy to study different melanin pigments at near-infrared wavelengths. Excited-state absorption, ground-state depletion, and stimulated emission signal contributions were distinguished for natural and synthetic eumelanins and pheomelanins. A starker contrast among the pigments is observed in the nonlinear excitation regime because they all exhibit distinct transient absorptive amplitudes, phase shifts, and nonexponential population dynamics spanning the femtosecond-nanosecond range. In this manner, different pigments within the pheomelanin subclass were distinguished in synthetic and human hair samples. These results highlight the potential of nonlinear spectroscopies to deliver an in situ analysis of natural melanins in tissue that are otherwise difficult to extract and purify.
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    Stable isotope ratios indicate diet and habitat use in New World monkeys.
    (Am J Phys Anthropol, 1997-05) Schoeninger, MJ; Iwaniec, UT; Glander, KE
    This paper demonstrates the use of stable isotope ratios of carbon and nitrogen in animal tissue for indicating aspects of species behavioral strategy. We analyzed hair from individuals representing four species of New World monkeys (Alouatta palliata, the mantled howler; Ateles geoffroyi, the spider monkey; Cebus capucinus, the capuchin; and Brachyteles arachnoides, the woolly-spider monkey or muriqui) for delta 13C and delta 15N using previously developed methods. There are no significant differences in either carbon or nitrogen ratios between sexes, sampling year, or year of analysis. Seasonal differences in delta 13C reached a low level of significance but do not affect general patterns. Variation within species was similar to that recorded previously within single individuals. The omega 13C data show a bimodal distribution with significant difference between the means. The two monkey populations living in an evergreen forest were similar to each other and different from the other two monkey populations that inhabited dry, deciduous forests. This bimodal distribution is independent of any particular species' diet and reflects the level of leaf cover in the two types of forest. The delta 15N data display three significantly different modes. The omnivorous capuchins were most positive reflecting a trophic level offset. The spider monkeys and the muriquis were similar to one another and significantly more positive than the howlers. This distribution among totally herbivorous species correlates with the ingestion of legumes by the howler monkey population. In combination, these data indicate that museum-curated primate material can be analyzed to yield information on forest cover and diet in populations and species lacking behavioral data.
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    Straight Hair, Brown Skin, and a Killa' Shape: Beauty Standards for Young Black Girls
    (2011-05-04) Johnson, Naomi
    My goal in conducting this research is to include black adolescent women in the discourse on body image, respond to the shortcomings of the literature and research attempting to speak on behalf of black adolescent women, and empower black adolescent women to address and complicate these prevailing misconceptions by encouraging them to speak on their own behalf. Based on the qualitative research that I conducted with the 7th and 8th grade young black girls participating in “Girl Talk”, I found that there is a recognizable standard of beauty that young black girls desire to live up to. The girls identified straight, long, flowy hair, medium skin, and a curvy but skinny shape as an approved template for attaining beauty. On the other hand, the girls felt insecure when they did not have their hair done, were poorly dressed, or felt that their skin was too dark. As the girls actively negotiated black womanhood, they remained both connected and disconnected to a legacy that preceded them. The issues that the girls were facing such as a desire for agency, self-definition, inclusion and mobility were very similar to the desires of black women in the past. As the girls navigated beauty ideals, their awareness of the battle they were simultaneously fighting against racism (and the extent to which their social norms have been intoxicated with white ideals) remained vastly underdeveloped.