白热斯油处方搽剂及其组分对人G-361细胞活力与产生黑色素能力的影响

探讨维吾尔医白热斯油处方搽剂及其单味药、即:补骨脂、白花丹、黄芥子、黑种草子和駆虫斑鳩菊生药材水提物等通过对G-361细胞存活率、增殖以及黑色素产生的影响。对维医白癜风专用12种处方水提物进行酪氨酸酶激活实验、根据激活率(OD值)进行排序并定位。用MTT法检测不同浓度白热斯油处方搽剂及其组分药材水提物、对G-361细胞72 h细胞存活率、增值以及黑色素产生进行观测。经检测、对维吾尔医12种治疗白癜风专用药材水提物酪氨酸酶激活率超出200%的有4个专用处方、白热斯油为第3位,高于其它9种处方(P<0.001)。各药材及各浓度72 h培养细胞存活率与对照组之间相比无显著性差异(P>0.05)。72 h培养细胞增殖和黑素产生能力与对照组相比有显著性差异、分别为P<0.05和P<0.01、而且最佳浓度集中在125μg/m L和62.5μg/m L、其中后者较为稳定。白热斯油处方及其组分药材水提物在适宜浓度,对72 h培养G-361细胞有增殖作用、使黑色素含量增加、且细胞存活率正常、未发现明显的细胞毒性作用。     

阿育魏实提取物对酪氨酸酶的激活作用

目的： 研究阿育魏实不同提取物对酪氨酸酶活性和黑色素生成的影响。 方法： 以阿育魏实为材料,通过乙醇提取得到总提取物即醇提物,然后依次用石油醚、三氯甲烷、乙酸乙酯、正丁醇萃取,得到相应的提取物。采用蘑菇酪氨酸酶多巴速率氧化法和NaOH裂解法研究了该提取物对酪氨酸酶的效应和黑色素上调率。 结果： 所得阿育魏实乙醇和乙酸乙酯提取物对酪氨酸酶激活作用较明显,对黑色素生成具有直接刺激作用,与对照品补骨脂和驱虫斑鸠菊相比,阿育魏实乙酸乙酯提取物IC₅₀为（13.64±7.78） g·L^-1,对酪氨酸酶激活作用优于临床治疗白癜风药物补骨脂[IC₅₀ （21.18±2.88） g·L^-1]。 结论： 阿育魏实乙酸乙酯提取物具有较好的体外酪氨酸酶激活及促进黑色素生成作用,可为临床治疗白癜风药物提供依据。     

脲溶性色素相关抗原诱导实验性葡萄膜炎研究

目的 探讨脲溶性牛黑素相关抗原能否在不同大鼠身上诱导实验性自身免疫性葡萄膜炎。 方法 将脲溶性牛黑素相关抗原加弗氏完全佐剂和百日咳杆菌分别免疫Lewis、F344及Wistar大鼠，通过临床观察和组织病理学对动物模型作动态观察比较。 结果 脲溶性牛黑素相关抗原可在Lewis、F344及Wistar大鼠身上诱导出实验性自身免疫性葡萄膜炎，其表现为双眼同时发病，以眼前段为主，个别严重者可伴有局灶性脉络膜炎，不伴视网膜炎和松果体炎，与牛黑素相关抗原所诱发的实验性自身免疫性前葡萄膜炎相类似。Lewis和F344大鼠发病时间及炎症严重程度相似，而Wistar大鼠发病时间较迟，炎症较轻。 结论 脲溶性牛黑素相关抗原可在Lewis、F344和Wistar大鼠身上诱导出实验性自身免疫性前葡萄膜炎。Wistar大鼠与Lewis和F344大鼠相比，发病时间较迟，炎症改变较轻，这种差异可能与遗传背景不同有关。(中华眼底病杂志,1998,14:149-152)     

Melanin as a virulence factor in pathogenic fungi

The pigment melanin is found universally in nature and is attributed to a variety of functions. In some fungi it is thought to play a decisive role in the determination of virulence. This review examines the experimental evidence which has led to an understanding of the mechanisms by which melanin functions in pathogenic fungi, particularly in plant pathogens, in Cryptococcus neoformans and Wangiella dermatitidis.     

Melanin and facial skin fluorescence as markers of yellowish discoloration with aging

Background: Although one clinical sign of aging and/or photoaging is a yellowish discoloration of the facial skin, little is known about the cause of this change. In addition to the increase in the epidermal melanin content, it has been suggested that advanced glycation end products (AGEs), which are known to accumulate in photoaged skin, may affect this discoloration. Aim: The objective of this pilot study was to non‐invasively investigate the roles of melanin and AGEs in this yellowish discoloration of the facial skin. Methods: We examined the spectral reflectance at the cheek in 40 healthy Japanese women of various ages (mean age, 38.1 years) using a reflectance spectrophotometer and a spectrofluorimeter. The degree of yellowish tint was evaluated in terms of b^*. The amount of melanin in the skin was evaluated by calculating the melanin index (MI) A₆₄₀–A₆₇₀ [A_λ: log₁₀ (1/reflectance) at a wavelength of λ]. The amount of AGEs was roughly evaluated using the AGEs index, which is thought to linearly correlate with the amount of intrinsic fluorescence markers irrespective of the concentration of melanin and is defined as follows: AGEs index=I₅/SQR (I₁×I₂). In this equation, the intensities of reflectance are I₁ at an excitation wavelength of 335 nm, I₂ at an emission wavelength of 390 nm and I₅ at 390 nm under an excitation wavelength of 335 nm. Results: Both b^* and the AGEs index were significantly correlated with subject age (r=0.34, P<0.05 and r=0.68, P<0.0001, respectively). Significant correlations were also observed between MI and b^* (r=0.63, P<0.0001) and between the AGEs index and b^* (r=0.53, P<0.0005). However, no significant correlations were seen between MI and the AGEs index. Conclusion: The AGEs index does not appear to be influenced by the amount of melanin and may be utilized as an indicator of the amount of AGEs in the skin. AGEs are likely to play a role in the yellowish discoloration of skin with aging.     

Optogenetic activation of melanin‐concentrating hormone neurons increases non‐rapid eye movement and rapid eye movement sleep during the night in rats

Neurons containing melanin‐concentrating hormone (MCH) are located in the hypothalamus. In mice, optogenetic activation of the MCH neurons induces both non‐rapid eye movement (NREM) and rapid eye movement (REM) sleep at night, the normal wake‐active period for nocturnal rodents [R. R. Konadhode et al. (2013) J. Neurosci., 33, 10257–10263]. Here we selectively activate these neurons in rats to test the validity of the sleep network hypothesis in another species. Channelrhodopsin‐2 (ChR2) driven by the MCH promoter was selectively expressed by MCH neurons after injection of rAAV‐MCHp‐ChR2‐EYFP into the hypothalamus of Long–Evans rats. An in vitro study confirmed that the optogenetic activation of MCH neurons faithfully triggered action potentials. In the second study, in Long–Evans rats, rAAV‐MCH‐ChR2, or the control vector, rAAV‐MCH‐EYFP, were delivered into the hypothalamus. Three weeks later, baseline sleep was recorded for 48 h without optogenetic stimulation (0 Hz). Subsequently, at the start of the lights‐off cycle, the MCH neurons were stimulated at 5, 10, or 30 Hz (1 mW at tip; 1 min on – 4 min off) for 24 h. Sleep was recorded during the 24‐h stimulation period. Optogenetic activation of MCH neurons increased both REM and NREM sleep at night, whereas during the day cycle, only REM sleep was increased. Delta power, an indicator of sleep intensity, was also increased. In control rats without ChR2, optogenetic stimulation did not increase sleep or delta power. These results lend further support to the view that sleep‐active MCH neurons contribute to drive sleep in mammals.     

Lateral hypothalamic 'command neurons' with axonal projections to regions involved in both feeding and thermogenesis

The concept of 'command neurons', whereby single neurons mediate complex and complementary motor functions to generate a stereotyped behaviour, is well developed in invertebrate physiology. The term has also been adopted more recently to explain the neural basis of 'fight or flight'. In this study we have investigated the possibility that single lateral hypothalamic neurons have the necessary neuroanatomical connections to coordinate two complementary limbs of body weight control, feeding and thermogenesis, thereby acting as 'command neurons'. The transynaptic retrograde transport of pseudorabies virus (Bartha) from a thermogenic endpoint in the brown adipose tissue of rats has been used in conjunction with other neuronal tracers, introduced into putative CNS feeding centres, to assess the potential for the involvement of command neurons in coordinating these processes. In discrete regions of the lateral hypothalamus, neurons have been identified which have the necessary complement of orexigenic peptides and collateral branching axons to both putative feeding sites and thermogenic sites in brown fat to qualify as candidate central command neurons controlling body weight.     

Inhibitory effects of 1,3‐thiazine derivatives on melanogenesis

Objectives The aim of this study was to identify a novel skin‐depigmenting agent from synthetic 1,3‐thiazine derivatives. Methods We investigated the inhibitory effects of six kinds of 1,3‐thiazine derivative on melanogenesis by examining their effects on tyrosinase activity and melanin biosynthesis in melan‐a cells and the zebrafish model. Key findings Of the six compounds, 4‐hydroxy‐2,6‐dimethyl‐5,6‐dihydro‐4H‐1,3‐thiazine (TZ‐6) had the strongest anti‐melanogenic effects in cultured melan‐a cells (30.4% inhibition at 100 μM). In addition, TZ‐6 exhibited an inhibitory effect on mushroom and cellular tyrosinase. Based on the results of Western blotting, TZ‐6 reduced the expression of tyrosinase at 100 mM. Additionally, TZ‐6 reduced body pigmentation and inhibited tyrosinase activity in the zebrafish model. Conclusions The results have provided useful information for the development of a skin whitening agent.     

甲氧沙林脂质体对小鼠黑素瘤细胞黑素生成影响的研究

目的:探讨甲氧沙林脂质体(8-MOPL)对小鼠B16F黑素瘤细胞增殖、黑素含量、酪氨酸酶活性的影响。方法:采用体外培养的小鼠B16F黑素瘤细胞株,以等浓度的甲氧沙林(8-MOP)为对照,用四甲基偶氮唑蓝(MTT)法测定细胞增殖情况;NaOH裂解法测定黑素合成;多巴氧化法测定酪氨酸酶活性。结果:与等浓度8-MOP相比,低浓度8-MOPL(10-25μmol/L)能显著提高酪氨酸酶活性和黑素含量(P<0.05)。高浓度8-MOPL(100-200μmol/L)对细胞的抑制作用更显著(P<0.05)。结论:用脂质体作为8-MOP的载体可以显著提高8-MOP对靶细胞的作用,为8-MOPL制剂治疗白癜风的临床应用提供了实验依据。