谷氨酸受体非竞争性拮抗剂及激动剂调节表皮细胞伪足形成及黑素小体转运的观察

【摘要】 目的 探讨谷氨酸信号通路在黑素细胞及角质形成细胞伪足形成及黑素小体转运中的作用机制。 方法 原代培养并纯化黑素细胞、角质形成细胞,建立黑素细胞与角质形成细胞体外共培养体系。扫描电镜观察离子型谷氨酸受体N-甲基-D-天冬氨酸（NMDA）受体非竞争性拮抗剂MK801及激动剂NMDA作用下黑素细胞、角质形成细胞的伪足形态变化,以311 nm中波紫外线（UVB）照射为阳性对照。免疫荧光双染色激光共聚焦显微镜下观察MK801及NMDA对黑素小体转运的调节。 结果 扫描电镜观察发现,100 μmol/L MK801作用24 h后黑素细胞树突末端明显变细,树突变长,树突数量无明显变化而细胞表面的丝状伪足数量明显变少,且伪足长度变短;100 μmol/L NMDA作用24 h后黑素细胞树突的末端明显变宽、树突变短,树突数量无明显变化而细胞表面丝状伪足数量明显增多,丝状伪足长度增加。黑素细胞与角质形成细胞共培养体系中,未用药组黑素细胞与角质形成细胞间有丝状伪足相连接,黑素细胞的角质形成细胞侧丝状伪足数量多于对侧。100 μmol/L MK801作用于共培养体系24 h后,黑素细胞与角质形成细胞之间的丝状伪足数量及黑素细胞伸向角质形成细胞的丝状伪足数量减少;100 μmol/L NMDA作用于共培养体系24 h后,黑素细胞与角质形成细胞之间的丝状伪足数量及黑素细胞伸向角质形成细胞的丝状伪足数量增多。激光共聚焦显微镜观察显示,共培养体系下,未用药组角质形成细胞中存在黑素小体;100 μmol/L MK801作用24 h后角质形成细胞中的黑素小体数量减少;100 μmol/L NMDA作用24 h后角质形成细胞中的黑素小体数量增多,且与黑素细胞不相邻的角质形成细胞中也发现黑素小体存在。 结论 谷氨酸信号通路可能通过调节黑素细胞树突的形态及丝状伪足的形成参与调节黑素小体自黑素细胞至角质形成细胞的转运。 【关键词】 角蛋白细胞; 黑素细胞; 谷氨酸; 伪足; 黑色素小体; 树突     

人表皮黑素细胞、毛囊无色素黑素细胞和鼠黑素瘤细胞的原子力显微镜观察

目的：观察培养的人表皮黑素细胞、毛囊无色素黑素细胞和S91鼠黑素瘤细胞的形态结构。方法：培养并纯化来自正常人包皮的黑素细胞以及来自毛囊的无色素黑素细胞，同时复苏S91细胞株，传代后接种到内置云母片的培养板中，细胞贴附到云母片上后固定，用原子力显微镜扫描观察。结果：正常人表皮黑素细胞有3级分支，在主干及分支的顶端和侧缘可见膨出的球形结构。鼠黑素瘤细胞仅有很短的2级分支，在2级树突近端可见黑素小体。毛囊无色素黑素细胞只有1级树突，并只在树突近端有少数黑素小体。结论：表皮黑素细胞在形态上比黑素瘤细胞、毛囊无色素黑素细胞更成熟，有更多的黑素颗粒从树突的顶端和侧缘以胞吐的形式被输出。     

人表皮黑素细胞与角质形成细胞共培养体外模型中黑素小体转运的观察

目的:建立人表皮黑素细胞与角质形成细胞共培养的体外模型,并且在模型中观察黑素小体的转运。方法:分别培养人表皮黑素细胞和角质形成细胞,用二乙酰羧基荧光素-琥珀酰亚胺酯(CFDA-SE)标记黑素细胞内黑素小体,然后将两种细胞共培养,并在倒置显微镜和共聚焦显微镜下观察共培养模型中黑素小体由黑素细胞向角质形成细胞的转运。结果:培养至第3天和第7天可在倒置显微镜下观察到黑素细胞与角质形成细胞共同存活,并通过树突发生联系,在共聚焦显微镜下可直接观察到黑素小体由黑素细胞向角质形成细胞的转运。结论:成功建立黑素细胞与角质形成细胞共培养的体外模型,并利用CFDA-SE标记,在共聚焦显微镜下直接观察到黑素向角质形成细胞的转运。     

龙胆草在人表皮黑素细胞与角质形成细胞共培养体系中对酪氨酸酶活性及黑素生成影响

目的：探讨龙胆草对人表皮黑素细胞与角质形成细胞共培养体系酪氨酸酶活性及黑素生成的影响。方法：培养人表皮黑素细胞与角质形成细胞共培养体系,利用四甲基偶氮唑蓝（MTT）还原法测定细胞活力,采用酶学方法测定酪氨酸酶活性,475nm比色法测定黑素含量。结果：0．1mg／mL、0．2mg／mL和0．5mg／mL龙胆草对于共培养细胞酪氨酸酶活性有较强的剂量相关性激活作用（P〈0．01）,0．2mg／mL及0．5mg／mL龙胆草与对于共培养细胞黑素生成有较强的剂量相关性激活作用（P〈0．01）。结论：龙胆草对于共培养体系酪氨酸酶活性及黑素生成有较强的剂量相关性激活作用。     

毛乳头细胞对毛囊前体黑素细胞作用的评价

目的：确定毛乳头细胞（DPC）对毛囊前体黑素细胞（MP）的激活和趋化作用。方法：采用三维分离式共培养体系,将MP与毛囊外毛根鞘角质形成细胞（KC）以1：10比例于6孔培养板中接触式共培养,DPC以1×10^6个／孔分离培养于Transwell inserts。检测DPC对MP的趋化作用。MP内黑素小体、酪氨酸酶（TYR）、酪氨酸酶相关蛋白1（TRP-1）和酪氨酸酶相关蛋白2（TRP-2）的表达。结果：MP与KC共培养后MP内出现Ⅲ期黑素小体,当三种细胞共培养后MP内主要为Ⅲ和Ⅳ期黑素小体。DPC可促进MP中TYR和TRP-1的表达,但对TRP-2的表达无明显影响,对MP具有明显趋化作用。结论：构建了MP、KC和DPC的三维培养体系,发现DPC对MP具有明显激活和趋化移行作用。     

皮肤黑素转运的调节机制

黑素是决定皮肤颜色的主要色素，它由黑素细胞合成。黑素细胞主要存在于皮肤和毛囊中，黑素在黑素小体内合成后，随其迁移到树突末端，树突朝邻近的角质形成细胞生长并释放。然后，黑素小体在多种分子的调节下，进入邻近的角质形成细胞，形成皮肤色素并起到有效的光防护作用。     

丹皮酚在体外对人黑素细胞酪氨酸酶活性及黑素生成的影响

目的探讨丹皮酚对人表皮黑素细胞与角质形成细胞共培养体系酪氨酸酶活性及黑素生成的影响。方法培养人表皮黑素细胞及人表皮黑素细胞与角质形成细胞共培养体系,利用四甲基偶氮唑蓝(MTT)还原法测定细胞活力,采用酶学方法测定酪氨酸酶活性,475nm比色法测定黑素含量。结果50,100和200μmol/L丹皮酚对于黑素细胞及共培养细胞酪氨酸酶活性及黑素生成均有较强的剂量相关性抑制作用,100及200μmol/L丹皮酚与对照组相比差异有统计学意义(P<0.01)。结论丹皮酚对于共培养体系酪氨酸酶活性及黑素生成有较强的剂量相关性抑制作用。     

人毛囊内无色素黑素细胞的原子力显微镜观察

目的用原子力显微镜观察人头发毛囊内无色素黑素细胞的表面结构。方法分离酶Ⅱ消化带毛囊的头皮，游离单个毛囊，以胰酶／EDTA消化之，获取细胞悬液，以添加黑素细胞生长物质的254培养基重悬细胞，常规培养。传第3代后接种到内置云母片的6孔培养板中，细胞贴附到云母片上后，固定．原子力显微镜常温常压下，触摸式扫描。结果毛囊无色素性黑素细胞多呈梭形，有2个突起，少数有3个树突。每个树突无明显的二级分枝，个别在树突侧缘有隆起。在一级树突的顶端可见丝状伪足。结论毛囊内无色素性黑素细胞形态不成熟，不能转运黑素颗粒到角质形成细胞，但它有黑素小体运动的物质基础——丝状伪足。     

两味中药单体对人黑素细胞酪氨酸酶活性及黑素合成的影响

目的: 探讨蛇床子素、黄芩苷对体外培养人黑素细胞及其与角质形成细胞共培养体系中酪氨酸酶活性及黑素合成的影响.方法: 培养人表皮黑素细胞及黑素细胞与角质形成细胞共培养体系,利用MTT法、多巴氧化法及NaOH法测定蛇床子素、黄芩苷对黑素细胞的增殖、酪氨酸酶活性及黑素合成的影响.以补骨脂素作为对照.结果: 蛇床子素、黄芩苷均可促进酪氨酸酶活性及增加黑素合成,但对共培养体系中黑素细胞的作用强于体外纯黑素细胞的作用(P<0.05);在对酪氨酸酶活性的影响中,黄芩苷的作用强于蛇床子素,其差异具有显著性(P<0.05);在对黑素合成的作用上,蛇床子素强于黄芩苷(P<0.05).结论:蛇床子素、黄芩苷对人黑素细胞酪氨酸酶活性及黑素合成均有较强的促进作用,且对共培养体系的作用强于对纯黑素细胞的作用.     

芒柄花素对人表皮共培养体黑素合成的影响

目的观察芒柄花素对人表皮黑素细胞与角质形成细胞共培养体系模型(人表皮共培养体)中酪氨酸酶活性及黑素合成的影响。方法建立人表皮共培养体,建成后分别加入30 mg/L、60 mg/L、120 mg/L芒柄花素,熊果苷为阳性对照组,测定芒柄花素和熊果苷对人表皮共培养体中酪氨酸酶活性以及黑素合成的影响。结果芒柄花素3种浓度对人表皮共培养体中酪氨酸酶活性及黑素合成与对照组比较均有明显抑制作用(P0.05),且浓度越高抑制作用越明显(P0.05)。高、中浓度芒柄花素黑素抑制率高于熊果苷(P0.05)。结论芒柄花素对黑素合成有明显抑制作用,机理与其对酪氨酸酶活性有抑制作用相关。     

New fillers for the new man

ABSTRACT:  Two new collagen-based lidocaine-containing dermal fillers, ArteSense™/ArteFill™ (Artes Medical, San Diego, CA) and Evolence® (Colbar LifeScience Ltd., Herzliya, Israel), have proved to be of particular interest to men, many of whom seek a long-lasting or permanent correction. ArteFill™ has been available in the United States since 2006, and it is expected that Evolence® will reach the American market in 2008. The properties of the two products will be described, and experience based on the administration of many hundreds of syringes of both products by a Canadian dermatologist will be detailed here, with tips and precautions to optimize patient outcomes.     

Outcomes and adverse effects of ablative vs nonablative lasers for skin resurfacing: A systematic review of 1093 patients

It is generally believed that ablative laser therapies result in prolonged healing and greater adverse events when compared with nonablative lasers for skin resurfacing. To evaluate the efficacy of ablative laser use for skin resurfacing and adverse events as a consequence of treatment in comparison to other modalities, a PRISMA‐compliant systematic review (Systematic Review Registration Number: 204016) of twelve electronic databases was conducted for the terms “ablative laser” and “skin resurfacing” from March 2002 until July 2020. Studies included meta‐analyses, randomized control trials, cohort studies, and case reports to facilitate evaluation of the data. All articles were evaluated for bias. The search strategy produced 34 studies. Of 1093 patients included in the studies of interest, adverse events were reported in a total of 106 patients (9.7%). Higher rates of adverse events were described in nonablative therapies (12.2% ± 2.19%, 31 events) when compared with ablative therapy (8.28% ± 2.46%, 81 events). 147 patients (13.4%) reported no side effects, 68 (6.22%) reported expected, transient self‐resolving events, and five (0.046%) presented with hypertrophic scarring. Excluding transient events, ablative lasers had fewer complications overall when compared with nonablative lasers (2.56% ± 2.19% vs 7.48% ± 3.29%). This systematic review suggests ablative laser use for skin resurfacing is a safe and effective modality to treat a range of pathologies from photodamage and acne scars to hidradenitis suppurativa and posttraumatic scarring from basal cell carcinoma excision. Further studies are needed, but these results suggest that ablative lasers are a superior, safe, and effective modality to treat damaged skin.     

Genetic alterations in RAS‐regulated pathway in acral lentiginous melanoma

Studies integrating clinicopathological and genetic features have revealed distinct patterns of genomic aberrations in Melanoma. Distributions of BRAF or NRAS mutations and gains of several oncogenes differ among melanoma subgroups, while 9p21 deletions are found in all melanoma subtypes. In the study, status of genes involved in cell cycle progression and apoptosis was evaluated in a panel of 17 frozen primary acral melanomas. NRAS mutations were found in 17% of the tumors. In contrast, BRAF mutations were not found. Gains of AURKA gene (20q13.3) were detected in 37.5% of samples, gains of CCND1 gene (11q13) or TERT gene (5p15.33) in 31.2% and gains of NRAS gene (1p13.2) in 25%. Alterations in 9p21 were identified in 69% of tumors. Gains of 11q13 and 20q13 were mutually exclusive, and 1p13.2 gain was associated with 5p15.33. Our findings showed that alterations in RAS‐related pathways are present in 87.5% of acral lentiginous melanomas.     

Self‐resolving superficial primary cutaneous mucormycosis in a 7‐week‐old infant

A 7‐week‐old girl, born at 30 weeks' gestational age, presented to clinic for evaluation of a crop of vesicular lesions that were noted after removal of a bandage that had been in place for 4 days. A punch biopsy of the lesion revealed fungal elements that were later identified as Rhizopus spp. The lesion began to self‐resolve, and no further treatment was needed, with full resolution of the lesion by 1 month after presentation. Clinicians should be aware of the variable presentations of mucormycosis and consider fungal infection in the differential diagnosis when evaluating vulnerable patients with skin eruptions.     

Pathogenic role of IL-17 in psoriasis and psoriatic arthritis

Psoriasis is a chronic inflammatory skin disorder resulting from a complex network of cytokines and chemokines produced by various immune cell types and tissue cells. Emerging evidence suggests a central role of IL-17 and IL-23/T17 axis in the pathogenesis of psoriasis, giving a rationale for using IL-17-blocking agents as therapeutics.Three agents targeting IL-17 signaling are being studied in Phase III clinical trials: secukinumab and ixekizumab (IL-17 neutralizing agents), and brodalumab (IL-17 receptor antagonist). Preliminary results are highly promising for all anti-IL17 agents, creating fair expectations on this class of agents as the new effective therapeutic approach for the treatment of psoriasis.