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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Demographic characteristics and association of serum Vitamin B12, ferritin and thyroid function with premature canities in Indian patients from an urban skin clinic of North India: A retrospective analysis of 71 cases

Sonthalia, S., Priya, A., Tobin, Desmond J. 12 May 2017 (has links)
Yes / Background: The incidence of self-reported premature hair graying (PHG) seems to be on the rise. PHG has a profound impact on the patient's quality of life. It remains an incompletely understood etiology with limited and modest treatment options. Aim: The evaluation of the demographic and clinical profile of patients with premature canities, and exploration of the association of this entity with certain systemic disorders suspected to be related to its etiology. Methods: Seventy-one cases of premature canities (onset noticed by patients before 25 years of age) presenting to an urban skin clinic in Gurugram, India, between September 2012 and September 2015 with this complaint were retrospectively analyzed. The patient records were retrieved that provided details of the onset, duration and pattern of involvement, history, and examination findings (scalp, cutis, and general physical). Since all these patients had been screened for anemia, thyroid disorder, fasting blood glucose, and Vitamin B12 levels at the time of presentation, these parameters were also available for analysis. Results: The mean age at onset of graying was 10.2 ± 3.6 years (range: 5–19 years), with an almost equal gender distribution. The earliest age of onset recorded was 5 years. A positive family history of PHG (at least one of the biological parents or siblings) was obtained in 64 (90.1%) of the cases. The temporal regions of the scalp (35.2%) were most commonly involved followed by the frontal region (18.3%). Hypovitaminosis B12 and hypothyroidism showed significant association with the disorder, whereas anemia, serum ferritin, and fasting blood glucose did not. Conclusion: The age of onset of hair graying can be as low as 5 years. Temporal and frontal areas are the most commonly involved sites. A strong family history, Vitamin B12 deficiency, and hypothyroidism are strongly associated with PHG. Larger case–control studies are mandated for discerning the correlation of these and other risk factors with PHG.
2

Synthèse de peptides modifiés pour la lutte contre l’alopécie et la canitie, et développement de nouvelles méthodologies pour la polymérisation de séquences peptidiques. / Synthesis of modified peptide to fight against Alopecia and Canities, and new methodology to polymerize peptide sequences

Soultan, Al Halifa 10 December 2014 (has links)
De part leurs nombreuses activités biologiques et leur propriétés physicochmiques et structurales, les peptides présentent un intérêt considérable pour la conception de molécules actives mais aussi pour l'élaboration de biomatériaux. Pour lutter contre l'alopécie (perte de cheveux) et la canitie (blanchiment des cheveux), nous avons axé nos travaux sur la recherche de peptides bioactifs. Pour cela, nous avons identifié des peptides têtes de série provenant soit de la littérature soit d'un criblage réalisé par l'institut européen de biologie (IEB). Ces peptides têtes de séries ont été modifiés afin d'améliorer leur activité et leur biodisponibilité tout en tenant compte du mode d'administration par voie topique. Lors de ce travail, nous avons également développé deux nouvelles méthodologies permettant la polymérisation de séquences peptidiques. En effet, les polymères à base de peptide présentent un intérêt majeur pour des applications en biotechnologie (tissus artificiels, implants), ou comme systèmes de transport ou de délivrance de principes actifs. Nous avons notamment mis au point la polymérisation de peptides hybrides présentant des fonctions dimethylsilanol ainsi que la polymérisation par ouverture du cycle de N-carboxyanhydrides portant une séquence peptidique. Ces deux stratégies ont permis d'obtenir des polymères linéaires ou en peigne. / Because of their numerous biological activities and their structural and physico-chemical properties, peptides are of considerable interest for the design of active molecules but also for the development of biomaterials. To fight against alopecia (hair loss) and canities (whitning hair), we focused our attention on the research of bioactive peptides. In this context, we have identified leads peptides either from the literature or from a screening conducted by the European Institute of Biology (IEB). These Leads were modified to improve their activity and bioavailability knowing that they will be applied topically. In this work, we have also developed two new methodologies for the polymerization of peptide sequences. Indeed, peptide-based polymers are of major interest for applications in biotechnology (i.e. artificial tissue,implants), or as systems of transport and delivery of drug. The first methodology relies on the polymerization of the hybrid peptides displaying dimethyl hydroxysilane functions. The other one involves the ring opening polymerization of N-carboxyanhydrides bearing a peptide sequence. Both strategies were used to obtain linear or comb peptide-polymers.
3

The cell biology of human hair follicle pigmentation.

Tobin, Desmond J. 10 November 2010 (has links)
No / Although we have made significant progress in understanding the regulation of the UVR-exposed epidermal-melanin unit, we know relatively little about how human hair follicle pigmentation is regulated. Progress has been hampered by gaps in our knowledge of the hair growth cycle’s controls, to which hair pigmentation appears tightly coupled. However, pigment cell researchers may have overly focused on the follicular melanocytes of the nocturnal and UVR-shy mouse as a proxy for human epidermal melanocytes. Here, I emphasize the epidermis-follicular melanocyte pluralism of human skin, as research models for vitiligo, alopecia areata and melanoma, personal care/cosmetics innovation. Further motivation could be in finding answers to why hair follicle and epidermal pigmentary units remain broadly distinct? Why melanomas tend to originate from epidermal rather than follicular melanocytes? Why multiple follicular melanocyte sub-populations exist? Why follicular melanocytes are more sensitive to aging influences? In this perspective, I attempt to raise the status of the human hair follicle melanocyte and highlight some species-specific issues involved which the general reader of the pigmentation literature (with its substantial mouse-based data) may not fully appreciate.
4

Androgenetic alopecia : a possible treatment and a relationship with hair greying : assessment of the herbal mixture Xiantene for the treatment of androgenetic alopecia and a relationship between early hair greying and the progression of androgenetic alopecia

Davies, Paul Gorton January 2010 (has links)
Hair plays an important role in human social and sexual communication. The androgen-stimulated, patterned loss of hair in cases of androgenetic alopecia (or common baldness) in genetically pre-disposed individuals, is associated with ageing and can cause marked phychological distress. However, it is poorly controlled. To investigate the effectiveness of daily topical application of a Chinese medicine-derived herbal mixture, Xiantene, on balding progression, two double-blind, placebo-controlled studies (3 and 12 months) were carried out on balding men using the trichogram approach. Xiantene significantly increased both the total number of hairs and those in anagen, improving the ratio of anagen:telogen hairs. This suggests that topical Xiantene increased the length of the anagen phase and may promote a cessation, or partial reversal, of the progression of androgenetic alopecia in men. Canities, loss of scalp hair colour, is another mark of ageing. To investigate whether early greying may protect follicles from androgenetic alopecia, the extent of alopecia, assessed using the Hamilton scale, was compared between men who first became grey before, or after, 30. Both alopecia and greying increased with age in 843 men (217 European, 626 Thai) whenever they first started greying. However, men who showed greying before 30 were significantly less bald, though more grey, in both groups. Hair follicle melanocytes synthesise the pigment melanin, producing reactive oxygen species (ROS) and oxidative stress; losing melanocyte pigmentary activity, and therefore these toxic factors, appears to enable hair follicles to maintain their full size for longer, despite the androgen drive to miniaturisation.
5

Androgenetic alopecia: a possible treatment and a relationship with hair greying. Assessment of the herbal mixture Xiantene for the treatment of androgenetic alopecia and a relationship between early hair greying and the progression of androgenetic alopecia

Davies, Paul G. January 2010 (has links)
Hair plays an important role in human social and sexual communication. The androgen-stimulated, patterned loss of hair in cases of androgenetic alopecia (or common baldness) in genetically pre-disposed individuals, is associated with ageing and can cause marked phychological distress. However, it is poorly controlled. To investigate the effectiveness of daily topical application of a Chinese medicine-derived herbal mixture, Xiantene, on balding progression, two double-blind, placebo-controlled studies (3 and 12 months) were carried out on balding men using the trichogram approach. Xiantene significantly increased both the total number of hairs and those in anagen, improving the ratio of anagen:telogen hairs. This suggests that topical Xiantene increased the length of the anagen phase and may promote a cessation, or partial reversal, of the progression of androgenetic alopecia in men. Canities, loss of scalp hair colour, is another mark of ageing. To investigate whether early greying may protect follicles from androgenetic alopecia, the extent of alopecia, assessed using the Hamilton scale, was compared between men who first became grey before, or after, 30. Both alopecia and greying increased with age in 843 men (217 European, 626 Thai) whenever they first started greying. However, men who showed greying before 30 were significantly less bald, though more grey, in both groups. Hair follicle melanocytes synthesise the pigment melanin, producing reactive oxygen species (ROS) and oxidative stress; losing melanocyte pigmentary activity, and therefore these toxic factors, appears to enable hair follicles to maintain their full size for longer, despite the androgen drive to miniaturisation. / Tri-Mill Charitable Trust, Global Beauty International Management Ltd.

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