第一届世界毛发学学术大会内容简述

毛发学（Ｔｒｉｃｈｏｌｏｇｙ）是一门研究毛发生理特性及其疾病的科学，是皮肤科学的一个特殊分支。毛发学以一门科学出现仅是２０世纪３０年代的事。１９２６年Ｄｒｙ首先描述了毛发生长周期：生长期、退行期、休止期；１９２７年ＦｅｌｉｘＰｉｎｋｕｓ进行了毛囊发生...     

毛发疾病

褪黑素对毛发生长的影响（综述）;脱发对患者心理及精神的影响（综述）;脱发患者生活质量调查;复方甘草酸苷治疗斑秃107例临床疗效观察;复方甘草酸苷治疗斑秃55例疗效观察     

健康人群毛发分布影响因素的研究进展

健康人群毛发分布的相关数据对于客观评价毛发生理或病理变化及评估各种治疗毛发疾病药物的疗效具有重要作用,健康人群毛发分布受到人种差异、衰老等多种因素的影响,本文将对这些因素的研究进展进行综述。     

毛发游离移植术

毛发游离移植近年发展较快 ,其中最大的进展是使用手术显微镜制作微型移植物并以各种新设计的器械将之植入小的受区切口之中 ,使移植结果更自然。本文就脱发生理、患者的选择和手术设计、供区和移植物的制备、受区和移植物的植入、以及该技术的展望作了综述。     

小鼠毛发周期相关的蛋白质组学初步研究

目的:构建小鼠毛发周期的动物模型,筛选差异表达蛋白.方法:提取不同毛发周期(0,8,20 d)蛋白质样品进行双向电泳分离及质谱分析,识别差异表达的蛋白质.结果:其中45 个蛋白通过质谱分析和SwissProt 蛋白数据库检索得到鉴定,如肌球蛋白轻链、原肌球蛋白1、膜联蛋白A、核纤层蛋白A/C、延伸因子1、细胞色素b、磷酸甘油醛脱氢酶等.结论:初步筛选出毛发周期中存在的45 个差异表达的蛋白,为今后的研究提供方向.     

31例成年男性头发生长特性的初步观察

目的 探讨中国成年男性头发的生长特性.方法 将31名志愿者头皮顶部及颞部各剃去约1.2 cm×1.2 cm范围内的头发;间隔7天后对上述部位微距照相,分析图像,得到头发密度及头发生长速度;拔取观察部位的头发,显微镜下测量头发尖端、中部及根部的直径.结果 31例成年男性头发密度为(132±42)根/cm²,顶部的头发密度显著高于颞部(P<0.001).头发生长速度为(461±44)μm/d,颞部的头发生长速度显著高于顶部(P<0.01).头发直径为(97±9)μm,顶部和颞部之间头发直径差异无统计学意义(P>0.05),头发尖端、中部及根部之间直径的差异亦无统计学意义(P>0.05).结论 与白人和非洲人相比,中国成年男性头发的密度较低,但头发生长速度较快.     

面部肤色丘疹——毛皮上皮瘤

患者女,37岁.面部丘疹10余年.患者10余年前发现双侧鼻唇沟出现数个粟粒大丘疹,未予诊治,随年龄增长丘疹增大、增多,渐至豌豆大,无自觉症状.皮肤科检查:双侧鼻唇沟、鼻根部可见簇集的豌豆至黄豆大圆形或椭圆形肤色丘疹,皮损呈半球形,质硬,表面光滑,对称分布,少数融合,皮损表面无破溃和毛细血管扩张.     

毛发游离移植术

毛发游离移植近年发展较快,其中最大的进展是使用手术显微镜制作微型移植物并以各种新设计的器械将之植入小的受区切口之中,使移植结果更自然。本文就脱发生理、患者的选择和手术设计、供区和移植物的制备、受区和移植物的植入、以及该技术的展望作了综述。     

白癜风病人发锌检查结果分析

微量元素与白癜风的关系,是近年来正在研究的一个课题.为探讨锌与白癜风的关系,我们自1986~1987年检测了白癜风患者头发中微量元素锌的含量,并与正常对照组加以分析比较,现将结果报告如下.     

毛发图像分析技术及其应用进展

毛发图像分析技术是一种客观定量地评估毛发生长情况的方法,具有非侵入性、完整性、精确性及可重复性等优点,已经被广泛地用于毛发基础研究和临床药物研究.近年来,研究者尝试将数字成像分析系统与之结合,以使该技术趋于计算机化和标准化.目前,毛发图像分析技术已经成为相关毛发研究领域公认的评估毛发生长状况的标准方法,但在实现可靠的计算机化测量以及降低测试成本两个方面有待进一步完善.     

褪黑激素及其受体对毛囊的作用

褪黑激素是松果体分泌的主要产物,其生物学作用及其受体在毛囊中的表达与毛发的生长和色素沉着有着密切关系,褪黑激素不仅作用于相应受体,还能通过雄激素受体和雌激素受体介导的信号传导通路起作用,对褪黑激素的深入研究也许可以为毛发疾病的临床治疗提供新的靶点.     

Alterations of melatonin secretion in atopic eczema

The circadian rhythm of melatonin secretion of the pineal gland can be disturbed in a variety of clinical conditions and diseases including some psychic disorders. To study the rhythmic behaviour of melatonin secretion in atopic eczema (AE), melatonin serum levels were measured every 2 h, starting at 8 a.m. in 18 patients suffering from severe AE. In 6 patients exhibiting low serum levels of melatonin, the circadian melatonin rhythm was found to be abolished. In 8 patients a diminished nocturnal melatonin increase was observed compared with the controls (n = 40). Only 4 patients showed a normal secretion pattern of melatonin. The results provide some evidence of a dysfunction of the pineal gland in AE, possibly due to a partially reduced activity of the sympathetic nervous system being involved in the control of melatonin secretion.     

Melatonin as a major skin protectant: from free radical scavenging to DNA damage repair

Abstract:  Melatonin, one of the evolutionarily most ancient, highly conserved and most pleiotropic hormones still operative in man, couples complex tissue functions to defined changes in the environment. Showing photoperiod-associated changes in its activity levels in mammals, melatonin regulates, chronobiological and reproductive systems, coat phenotype and mammary gland functions. However, this chief secretory product of the pineal gland is now recognized to also exert numerous additional functions which range from free radical scavenging and DNA repair via immunomodulation, body weight control and the promotion of wound healing to the coupling of environmental cues to circadian clock gene expression and the modulation of secondary endocrine signalling (e.g. prolactin release, oestrogen receptor-mediated signalling). Some of these activities are mediated by high-affinity membrane (MT1, MT2) or specific cytosolic (MT3/NQO2) and nuclear hormone receptors (RORα), while others reflect receptor-independent antioxidant activities of melatonin. Recently, it was shown that mammalian (including human) skin and hair follicles are not only melatonin targets, but also sites of extrapineal melatonin synthesis. Therefore, we provide here an update of the relevant cutaneous effects and mechanisms of melatonin, portray melatonin as a major skin protectant and sketch how its multi-facetted functions may impact on skin biology and pathology. This is illustrated by focussing on recent findings on the role of melatonin in photodermatology and hair follicle biology. After listing a number of key open questions, we conclude by defining particularly important, clinically relevant perspectives for how melatonin may become therapeutically exploitable in cutaneous medicine.     

Melatonin as an antioxidant – a role in human aging?

N -Acetyl-5-methoxytryptamine, commonly known as melatonin, was isolated and structurally identified by a dermatologist, Aaron B. Lerner, in 1958. His interest stemmed from the fact that melatonin has potent skin-lightening effects in amphibians and some other non-mammalian species. In humans, however, melatonin is not capable of lightening skin or in reducing pigmentation. While melatonin synthesis is the best known to occur in the pineal gland, it is also produced in several other organs including the skin. Melatonin is a powerful, multifaceted direct free radical scavenger and indirect antioxidant. Numerous studies have shown that melatonin production wanes with increasing age and its loss has been speculated to be consequential in free radical-mediated cellular and organ deterioration that occurs in the elderly. Additionally, a number of free radical-related diseases, e.g. Alzheimer's disease, Parkinsonism, cataract formation, etc., may in part be a consequence of the loss of endogenous melatonin production. The administration of melatonin in animal models of these diseases typically defers their progression and limits their severity. Likewise, due to its antioxidant properties and via other mechanisms, melatonin may reduce skin aging. Melatonin, when applied topically to the skin of humans, has obvious protective effects against ultraviolet (UV) light-induced erythema. Also, lipid peroxidation in human skin fibroblasts due to their exposure to UV-B is reduced when melatonin is present.     

Plasma melatonin levels in psoriasis

Melatonin is synthesized and secreted by the pineal gland. A daily rhythm of melatonin secretion, with high plasma values during the dark period, has been found in all vertebrates studied so far. In psoriatics, several hormones, including GH and prolactin, have altered chronobiology, and some studies in humans suggest that melatonin affects the levels of GH and prolactin. We investigated circadian melatonin rhythm in 13 male psoriatics and 13 healthy males with an RIA specific for measuring the hormone in plasma. Samples were taken at 6 a.m., 8 a.m., 12.00, 4 p.m., 8 p.m. and 2 a.m. Differences in (mean +/- SD) plasma melatonin levels were analysed by Student's t-test. Our results show that psoriatic patients had lost the nocturnal peak and usual circadian rhythm of melatonin secretion. Levels of melatonin were significantly lower than in controls at 2 a.m., and higher at 6 and 8 a.m. and at 12 noon. Further investigations of this disorder of melatonin secretion in psoriasis are needed to understand its significance.     

Melatonin reduces X-ray irradiation-induced oxidative damages in cultured human skin fibroblasts

Melatonin is a hormone with multiple functions in humans, produced by the pineal gland and stimulated by beta-adrenergic receptors. Melatonin has been shown to have radioprotection properties, but there has been little progress toward identifying the specific mechanisms of its action. To clarify the role of melatonin as a radioprotective compound, in response to X-ray irradiation, we investigated the effects of X-ray irradiation and melatonin on cytotoxicity, lipid peroxidation and alteration of the cell cycle in cultured skin fibroblast. An 8 Gy dose of X radiation resulted in cell death in 63% of irradiated cells, i.e. the cell viability was 37%. The damage was associated with lipid peroxidation of the cell membrane, as shown by the accumulation of malondialdehyde (MDA). By pre-incubation with melatonin (10(-5) M), a significant preventive effect was noted on the increase in the absolute number of surviving cells (up to 68% of cells were survived), and the levels of MDA were markedly decreased. These findings suggest a close correlation between an increase of lipid peroxidation and a rate of cell death. Morphological changes associated with apoptotic cell death were demonstrated by TEM. DNA flow-cytometry analysis revealed that X radiation increased pre-G1 apoptotic population by 7.6% compared to a very low level (1.3%) of non-irradiated cells. However, in the presence of melatonin, this apoptotic population decreased up to 4.5% at 10(-5) M. The p53 and p21 protein levels of skin fibroblasts increased 4 h after 8 Gy irradiation, but melatonin pretreatment did not change those levels. This study suggests that melatonin pretreatment inhibits radiation-induced apoptosis, and melatonin exerts its radioprotective effect by inhibition of lipid peroxidation and without any involvement of the p53/p21 pathway.     

Einfluss von Melatonin auf die Physiologie des Haares

Melatonin, the pineal gland hormone and a strong antioxidant, has long been known, particularly in animal-experiment based research and the wool-producing industry, to be a potent regulatory neuroendocrine substance in relation to hair growth, hair color and hair cycle, depending on light periods, seasonal rhythms, environmental factors and reproductive rhythms. Nevertheless, the biological mechanisms of this extremely versatile hormone, especially with regard to human hair follicles, are not fully understood. In recent years, however, essential knowledge has been gained on the melatoninergic system of the skin, melatonin levels in keratinocytes and hair follicles, extrapineal intrafollicular melatonin synthesis and noradrenalin-induced increase in synthesis, as well as hair cycle-dependent expression of the membrane-bound melatonin receptor MT2 and the nuclear receptor RORα. Functional data on the growth of human hair both in vitro and in vivo show that melatonin might play an essential role in hair physiology.     

Melatonin in der Dermatologie Experimentelle und klinische Aspekte

Melatonin (N-acetyl-5-methoxytryptamine) is a hormone with multiple functions in humans, produced by the pineal gland and stimulated by beta-adrenergic receptors. Serum melatonin levels exhibit a circadian rhythm with low levels during the day, rise in the evening and maximum levels at night between 2 and 4 a.m. Melatonin participates in the regulation of several physiological processes such as seasonal biological rhythm, daily sleep induction, aging and modulation of immunobiological defence reactions. Furthermore, melatonin has a highly lipophilic molecular structure facilitating penetration of cell membranes and serving as an extra- and intracellular free radical scavenger. Melatonin seems to quench mainly hydroxyl radicals, the most damaging of all free radicals. Melatonin may play a role in the etiology and treatment of several dermatoses e.g. atopic eczema, psoriasis and malignant melanoma. The influence of melatonin on hair growth is another aspect. Topical application of melatonin inhibits the development of UV-erythema. Penetration through skin after topical application and oral bioavailability auxit further investigations on the pharmacokinetic and pharmacodynamic actions of melatonin.     

Integral hair lipid in human hair follicle

Integral hair lipid (IHL) is bound to the keratinized cell surface to make an environmentally resistant lipid envelope. It is mainly positioned on the hair cuticle and inner root sheath. IHL in the hair follicle may regard as hair barrier to be similar to the epidermal lipid layer functioning as skin barrier. Major constituents of IHL are fatty acid, phytosphingosine, ceramide in decreasing order. Minor constituents of IHL are cholesterol, cholesterol sulfate and cholesterol oleate. Cuticle or cortical cell surface in hair are abundant in fatty acids unlike the keratinized area of epidermis or sebaceous gland, and about 30-40% of such fatty acids are composed of 18-methyl-eicosanoic acid which is known to be bound to proteins by ester or thioester bond. Various factors including moisture, solvent, oxidative damage during bleaching or permanent waving affect IHL. Photochemical changes also can occur in IHL as well as in hair protein and hair pigment. Lipid metabolism is thought to play an essential role in lipid envelope of hair, but also involvement in hair development and function.     

The effects of the melatonin on ultraviolet-B irradiated cultured dermal fibroblasts

It has been reported that reactive oxygen species (ROS) and oxygen-derived free radicals are generated by ultraviolet (UV) radiation and various chemicals and their important roles in cellular damage and apoptosis are being increasingly recognized. Melatonin is a hormone with multiple functions in humans, produced by the pineal gland and stimulated by beta-adrenergic receptors. Melatonin has been shown to have photo protection properties, but there has been little progress toward identifying the specific mechanisms of its action. To clarify the role of melatonin as a free radical scavenger, in response to ultraviolet-B (UVB) irradiation, we investigated the effects of UVB and melatonin on cytotoxicity, lipid peroxidation, terminal deoxynucleotidyl transferase-mediated digoxigenin-dUTP nick end-labeling (TUNEL) assay and alteration of cell cycle in cultured skin fibroblast. Cell survival curves after UVB irradiation showed dose dependent decrement pattern by trypan blue exclusion assay. Only 56% of dermal fibroblasts were survived at 140 mJ/cm2 UVB irradiation. The damage was associated with cell membrane lipid peroxidation, as shown by accumulation malondialdehyde (MDA). By pre-cultivation with melatonin (10(-9) M), a significant preventive effect was noted on the increase in the absolute number of surviving cells (up to 92.5% of cells were survived) and the levels of MDA were markedly decreased. These finding suggest significant correlation between an increase of lipid peroxide and cell viability. Morphological changes associated with apoptotic cell death were easily distinguished by TUNEL stain. Quantitative analysis of DNA content of skin fibroblasts was evaluated by flow cytometric analysis performed after vital staining with propidium iodide. UVB suppresses the G1 progression induced pre-G1 arrest leading to apoptotic changes of dermal fibroblast and those are blocked by melatonin pre-treatment. The results show the photodynamic effects of UVB that supposes the production of ROS and arrest the cell cycle. Melatonin, which have newly accepted as a potential UV protection properties, is effective membrane peroxidation inhibitor and prevent the pre-G1 arrest when present in relevant concentration during UVB irradiation.