8 resultados para hair growth

em BORIS: Bern Open Repository and Information System - Berna - Suiça


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BACKGROUND Hirsutism occurs in 5% to 10% of women of reproductive age when there is excessive terminal hair growth in androgen-sensitive areas (male pattern). It is a distressing disorder with a major impact on quality of life. The most common cause is polycystic ovary syndrome. There are many treatment options, but it is not clear which are most effective. OBJECTIVES To assess the effects of interventions (except laser and light-based therapies alone) for hirsutism. SEARCH METHODS We searched the Cochrane Skin Group Specialised Register, CENTRAL (2014, Issue 6), MEDLINE (from 1946), EMBASE (from 1974), and five trials registers, and checked reference lists of included studies for additional trials. The last search was in June 2014. SELECTION CRITERIA Randomised controlled trials (RCTs) in hirsute women with polycystic ovary syndrome, idiopathic hirsutism, or idiopathic hyperandrogenism. DATA COLLECTION AND ANALYSIS Two independent authors carried out study selection, data extraction, 'Risk of bias' assessment, and analyses. MAIN RESULTS We included 157 studies (sample size 30 to 80) comprising 10,550 women (mean age 25 years). The majority of studies (123/157) were 'high', 30 'unclear', and four 'low' risk of bias. Lack of blinding was the most frequent source of bias. Treatment duration was six to 12 months. Forty-eight studies provided no usable or retrievable data, i.e. lack of separate data for hirsute women, conference proceedings, and losses to follow-up above 40%.Primary outcomes, 'participant-reported improvement of hirsutism' and 'change in health-related quality of life', were addressed in few studies, and adverse events in only half. In most comparisons there was insufficient evidence to determine if the number of reported adverse events differed. These included known adverse events: gastrointestinal discomfort, breast tenderness, reduced libido, dry skin (flutamide and finasteride); irregular bleeding (spironolactone); nausea, diarrhoea, bloating (metformin); hot flushes, decreased libido, vaginal dryness, headaches (gonadotropin-releasing hormone (GnRH) analogues)).Clinician's evaluation of hirsutism and change in androgen levels were addressed in most comparisons, change in body mass index (BMI) and improvement of other clinical signs of hyperandrogenism in one-third of studies.The quality of evidence was moderate to very low for most outcomes.There was low quality evidence for the effect of two oral contraceptive pills (OCPs) (ethinyl estradiol + cyproterone acetate versus ethinyl estradiol + desogestrel) on change from baseline of Ferriman-Gallwey scores. The mean difference (MD) was -1.84 (95% confidence interval (CI) -3.86 to 0.18).There was very low quality evidence that flutamide 250 mg, twice daily, reduced Ferriman-Gallwey scores more effectively than placebo (MD -7.60, 95% CI -10.53 to -4.67 and MD -7.20, 95% CI -10.15 to -4.25). Participants' evaluations in one study with 20 participants confirmed these results (risk ratio (RR) 17.00, 95% CI 1.11 to 259.87).Spironolactone 100 mg daily was more effective than placebo in reducing Ferriman-Gallwey scores (MD -7.69, 95% CI -10.12 to -5.26) (low quality evidence). It showed similar effectiveness to flutamide in two studies (MD -1.90, 95% CI -5.01 to 1.21 and MD 0.49, 95% CI -1.99 to 2.97) (very low quality evidence), as well as to finasteride in two studies (MD 1.49, 95% CI -0.58 to 3.56 and MD 0.40, 95% CI -1.18 to 1.98) (low quality evidence).Although there was very low quality evidence of a difference in reduction of Ferriman-Gallwey scores for finasteride 5 mg to 7.5 mg daily versus placebo (MD -5.73, 95% CI -6.87 to -4.58), it was unlikely it was clinically meaningful. These results were reinforced by participants' assessments (RR 2.06, 95% CI 0.99 to 4.29 and RR 11.00, 95% CI 0.69 to 175.86). However, finasteride showed inconsistent results in comparisons with other treatments, and no firm conclusions could be reached.Metformin demonstrated no benefit over placebo in reduction of Ferriman-Gallwey scores (MD 0.05, 95% CI -1.02 to 1.12), but the quality of evidence was low. Results regarding the effectiveness of GnRH analogues were inconsistent, varying from minimal to important improvements.We were unable to pool data for OCPs with cyproterone acetate 20 mg to 100 mg due to clinical and methodological heterogeneity between studies. However, addition of cyproterone acetate to OCPs provided greater reductions in Ferriman-Gallwey scores.Two studies, comparing finasteride 5 mg and spironolactone 100 mg, did not show differences in participant assessments and reduction of Ferriman-Gallwey scores (low quality evidence). Ferriman-Gallwey scores from three studies comparing flutamide versus metformin could not be pooled (I² = 62%). One study comparing flutamide 250 mg twice daily with metformin 850 mg twice daily for 12 months, which reached a higher cumulative dosage than two other studies evaluating this comparison, showed flutamide to be more effective (MD -6.30, 95% CI -9.83 to -2.77) (very low quality evidence). Data showing reductions in Ferriman-Gallwey scores could not be pooled for four studies comparing finasteride with flutamide as the results were inconsistent (I² = 67%).Studies examining effects of hypocaloric diets reported reductions in BMI, but which did not result in reductions in Ferriman-Gallwey scores. Although certain cosmetic measures are commonly used, we did not identify any relevant RCTs. AUTHORS' CONCLUSIONS Treatments may need to incorporate pharmacological therapies, cosmetic procedures, and psychological support. For mild hirsutism there is evidence of limited quality that OCPs are effective. Flutamide 250 mg twice daily and spironolactone 100 mg daily appeared to be effective and safe, albeit the evidence was low to very low quality. Finasteride 5 mg daily showed inconsistent results in different comparisons, therefore no firm conclusions can be made. As the side effects of antiandrogens and finasteride are well known, these should be accounted for in any clinical decision-making. There was low quality evidence that metformin was ineffective for hirsutism and although GnRH analogues showed inconsistent results in reducing hirsutism they do have significant side effects.Further research should consist of well-designed, rigorously reported, head-to-head trials examining OCPs combined with antiandrogens or 5α-reductase inhibitor against OCP monotherapy, as well as the different antiandrogens and 5α-reductase inhibitors against each other. Outcomes should be based on standardised scales of participants' assessment of treatment efficacy, with a greater emphasis on change in quality of life as a result of treatment.

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The hair follicle has a lifelong capacity to cycle through recurrent phases of controlled growth (anagen), regression (catagen) and quiescence (telogen), each associated with specific morphological changes. A comprehensive classification scheme is available for mice to distinguish the cycle stages anagen I-VI, catagen I-VIII and telogen. For dogs, such a classification system does not exist, although alopecia associated with hair cycle arrest is common. We applied analogous morphological criteria and various staining techniques to subdivide the canine hair cycle stages to the same extent as has been done in mice. Of all the staining techniques applied, haematoxylin and eosin stain, Sacpic, Masson Fontana and immunohistochemistry for vimentin and laminin proved to be most useful. To evaluate the applicability of our criteria, we investigated skin biopsies from healthy beagle dogs (n=20; biopsies from shoulder and thigh) kept in controlled conditions. From each biopsy, at least 50 hair follicles were assessed. Statistical analysis revealed that 30% of the follicles were in anagen (12% early and 18% late), 8% in catagen (2% early, 5% late and 1% not determinable) and 27% in telogen. Thirty-five per cent of hair follicles could not be assigned to a specific cycle stage because not all follicles within one biopsy were oriented perfectly. In conclusion, this guide will not only be helpful for the investigation of alopecic disorders and possibly their pathogenesis, but may also serve as a basis for research projects in which the comparison of hair cycle stages is essential, e.g. comparative analysis of gene expression patterns.

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Hereditary hair length variability in mice and dogs is caused by mutations within the fibroblast growth factor 5 (FGF5) gene. The aim of this study was to evaluate the feline FGF5 orthologue as a functional candidate gene for the long hair phenotype in cats, which is recessive to short hair. We amplified the feline FGF5 cDNA and characterised two alternatively spliced transcripts by RT-PCR. Comparative cDNA and genomic DNA sequencing of long- and short-haired cats revealed four non-synonymous polymorphisms in the FGF5 coding sequence. A missense mutation (AM412646:c.194C>A) was found in the homozygous state in 25 long-haired Somali, Persian, Maine Coon, Ragdoll and crossbred cats. Fifty-five short-haired cats had zero or one copy of this allele. Additionally, we found perfect co-segregation of the c.194C>A mutation within two independent pedigrees segregating for hair length. A second FGF5 exon 1 missense mutation (AM412646:c.182T>A) was found exclusively in long-haired Norwegian Forest cats. The c.182T>A mutation probably represents a second FGF5 mutation responsible for long hair in cats. In addition to the c.194C>A mutation, a frameshift mutation (AM412646:c.474delT) was found with a high frequency in the long-haired Maine Coon breed. Finally, a missense mutation (AM412646:c.475A>C) was also associated with the long-haired phenotype in some breeds. However, as one short-haired cat was homozygous for this polymorphism, it is unlikely that it has a functional role in the determination of hair length.

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The mammalian Cutl1 gene codes for the CCAAT displacement protein (CDP), which has been implicated as a transcriptional repressor in diverse processes such as terminal differentiation, cell cycle progression, and the control of nuclear matrix attachment regions. To investigate the in vivo function of Cutl1, we have replaced the C-terminal Cut repeat 3 and homeodomain exons with an in-frame lacZ gene by targeted mutagenesis in the mouse. The CDP-lacZ fusion protein is retained in the cytoplasm and fails to repress gene transcription, indicating that the Cutl1(lacZ) allele corresponds to a null mutation. Cutl1 mutant mice on inbred genetic backgrounds are born at Mendelian frequency, but die shortly after birth because of retarded differentiation of the lung epithelia, which indicates an essential role of CDP in lung maturation. A less pronounced delay in lung development allows Cutl1 mutant mice on an outbred background to survive beyond birth. These mice are growth-retarded and develop an abnormal pelage because of disrupted hair follicle morphogenesis. The inner root sheath (IRS) is reduced, and the transcription of Sonic hedgehog and IRS-specific genes is deregulated in Cutl1 mutant hair follicles, consistent with the specific expression of Cutl1 in the progenitors and cell lineages of the IRS. These data implicate CDP in cell-lineage specification during hair follicle morphogenesis, which resembles the role of the related Cut protein in specifying cell fates during Drosophila development.

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BACKGROUND Follicular stem cells and their progeny are responsible for the cyclical renewal of hair follicles and maintenance of the hair coat. The understanding of pathways involved in this process is essential to elucidate the pathogenetic mechanisms of primary alopecia. Stem cells and their direct descendants are located in the bulge region of the isthmus of hair follicles. Although these cells have been studied extensively in mice and humans, data for canine isthmic keratinocyte activation and proliferation are not available. HYPOTHESIS/OBJECTIVES The aim was to establish an accurate and reliable in vitro system to study the growth potential of canine isthmic keratinocytes. We assessed the colony-promoting capability of a commercially available canine-specific medium, CELLnTEC (CnT-09), compared with a well-established home-made medium, complete FAD (cFAD). The CnT-09 medium is specific for the growth of canine keratinocytes, while the cFAD medium can support growth and colony formation of keratinocytes from several species. ANIMALS Skin biopsies were obtained from 15 recently euthanized dogs of various breeds with no skin abnormalities. METHODS The isthmic region of compound hair follicles was isolated by microdissection and cell growth monitored using several parameters with colony-forming assays. RESULTS The CnT-09 and cFAD media provided similar growth as measured by the total number and size of colonies, as well as rate of cell differentiation. CONCLUSIONS The commercial canine-specific CnT-09 medium was comparable to the home-made cFAD medium in supporting the growth and proliferation of canine follicular keratinocytes in vitro. The CnT-09 medium should be a viable alternative growth medium for molecular studies of alopecic disorders in dogs.

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Bacterial infections represent a rapidly growing challenge to human health. Aminoglycosides are widely used broad-spectrum antibiotics, but they inflict permanent hearing loss in up to ~50% of patients by causing selective sensory hair cell loss. Here, we hypothesized that reducing aminoglycoside entry into hair cells via mechanotransducer channels would reduce ototoxicity, and therefore we synthesized 9 aminoglycosides with modifications based on biophysical properties of the hair cell mechanotransducer channel and interactions between aminoglycosides and the bacterial ribosome. Compared with the parent aminoglycoside sisomicin, all 9 derivatives displayed no or reduced ototoxicity, with the lead compound N1MS 17 times less ototoxic and with reduced penetration of hair cell mechanotransducer channels in rat cochlear cultures. Both N1MS and sisomicin suppressed growth of E. coli and K. pneumoniae, with N1MS exhibiting superior activity against extended spectrum β lactamase producers, despite diminished activity against P. aeruginosa and S. aureus. Moreover, systemic sisomicin treatment of mice resulted in 75% to 85% hair cell loss and profound hearing loss, whereas N1MS treatment preserved both hair cells and hearing. Finally, in mice with E. coli-infected bladders, systemic N1MS treatment eliminated bacteria from urinary tract tissues and serially collected urine samples, without compromising auditory and kidney functions. Together, our findings establish N1MS as a nonototoxic aminoglycoside and support targeted modification as a promising approach to generating nonototoxic antibiotics.

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An unusual ice type, called hair ice, grows on the surface of dead wood of broad-leaf trees at temperatures slightly below 0 °C. We describe this phenomenon and present physical, chemical, and biological investigations to gain insight in the properties and processes related to hair ice. Tests revealed that the biological activity of a winter-active fungus is required in the wood for enabling the growth of hair ice. We confirmed the fungus hypothesis originally suggested by Wegener (1918) by reproducing hair ice on wood samples. Treatment by heat and fungicide suppresses the formation of hair ice. Fruiting bodies of Asco- and Basidiomycota are identified on hair-ice-carrying wood. One species, Exidiopsis effusa (Ee), was present on all investigated samples. Both hair-ice-producing wood samples and those with killed fungus show essentially the same temperature variation, indicating that the heat produced by fungal metabolism is very small, that the freezing rate is not influenced by the fungus activity, and that ice segregation is the common mechanism of ice growth on the wood surface. The fungus plays the role of shaping the ice hairs and preventing them from recrystallisation. Melted hair ice indicates the presence of organic matter. Chemical analyses show a complex mixture of several thousand CHO(N,S) compounds similar to fulvic acids in dissolved organic matter (DOM). The evaluation reveals decomposed lignin as being the main constituent. Further work is needed to clarify its role in hair-ice growth and to identify the recrystallisation inhibitor.

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Hair cycle disturbances are common in dogs and comparable to some alopecic disorders in humans. A normal hair cycle is maintained by follicular stem cells which are predominately found in an area known as the bulge. Due to similar morphological characteristics of the bulge area in humans and dogs, the shared particularity of compound hair follicles as well as similarities in follicular biomarker expression, the dog is a promising model to study human hair cycle and stem cell disorders. To gain insight into the spatial distribution of follicular keratinocytes with stem cell potential in canine compound follicles, we microdissected hair follicles in anagen and telogen from skin samples of freshly euthanized dogs. The keratinocytes isolated from different locations were investigated for their colony forming efficiency, growth and differentiation potential as well as clonal growth. Our results indicate that i) compound and single hair follicles exhibit a comparable spatial distribution pattern with respect to cells with high growth potential and stem cell-like characteristics, ii) the lower isthmus (comprising the bulge) harbors most cells with high growth potential in both, the anagen and the telogen hair cycle stage, iii) unlike in other species, colonies with highest growth potential are rather small with an irregular perimeter and iv) the keratinocytes derived from the bulbar region exhibit characteristics of actively dividing transit amplifying cells. Our results now provide the basis to conduct comparative studies of normal dogs and those with hair cycle disorders with the possibility to extend relevant findings to human patients.