杭白菊、当归、丹参提取液抑制黄褐斑形成及机制研究

目的观察杭白菊、当归、丹参提取液对im黄体酮及紫外(UV)照射导致的黄褐斑小鼠模型的抗氧化与抗黄褐斑形成作用。方法将小鼠随机分成对照组、模型组、维生素C组、杭白菊组、当归组、丹参组共6组。采用im黄体酮及辅助UV照射方法建立黄褐斑小鼠模型。测定各组肝脏及皮肤组织中的谷胱甘肽过氧化酶(GSH-Px)、超氧化物歧化酶(SOD)、酪氨酸酶(TYR)活性与总抗氧化能力(T-AOC),以及丙二醛(MDA)、一氧化氮(NO)、肝脏脂褐质水平,并测定血液流变学指标,进行皮肤病理学检查。结果杭白菊、当归、丹参提取液显著增强黄褐斑小鼠肝脏和皮肤中GSH-Px、SOD活性,降低MDA水平,抑制TYR增加,使黑素细胞(MC)生成减少,抑制黑色素合成,从而减轻皮肤色素沉着。结论杭白菊、当归、丹参提取液有一定的防治黄褐斑的功效,其作用与提高机体抗氧化能力,抑制TYR活性,减少黑色素的合成以及改善机体的血液流变学有关。     

止血环酸抑制黑色素合成的实验研究

目的 观察止血环酸抑制黑素瘤细胞的黑素合成作用并探讨其机理。方法 比色法和免疫组化法分别用于B16黑素瘤细胞黑素含量测定和酪氨酸酶测定，氨基酸自动分析仪和高效液相色谱用于酪氨酸酶代谢的测定。结果 止血环酸虽不能抑制B16黑素瘤细胞生长和减少黑素瘤细胞酪氨酸酶含量，但能干扰酪氨酸酶对酪氨酸的催化作用，减少黑素合成。结论 止血环酸是通过干扰酪氨酸酶的酪氨酸催化作用抑制黑素合成。     

六味地黄丸对体外培养黑素细胞的抑制作用

目的 :研究六味地黄丸对体外培养的黑素细胞的抑制作用。方法 :采用 MTT法测定细胞增殖情况 ;Na OH裂解法测定黑素合成 ;Takahashi法测定酪氨酸酶含量。结果 :六味地黄丸对黑素细胞的增殖有抑制作用 ,能使细胞数明显减少 (P<0 .0 5 ) ,并能使黑素合成显著下降 (P<0 .0 1) ,使酪氨酸酶活性逐渐减弱 (P<0 .0 1)。结论 :六味地黄丸能抑制黑素细胞增殖、黑素合成、酪氨酸酶活性 ,这可能是临床应用六味地黄丸治疗皮肤色素性疾病的机制     

Do different ethnic groups need different sun protection?

Background: In the present study, the transmission of sunlight trough the human skin barrier into the living tissue was investigated in the spectral region between 280 and 700 nm.
Methods: The experiments were performed with a fiber-based spectrometer on sliced skin obtained from volunteers with different skin types. One fiber was positioned directly on the skin surface and the second one underneath the skin samples. The distribution of the sunlight under the epidermis was determined.
Results: Significant differences were found in the absorption properties of the different skin types, which were mainly determined by the variations in melanin concentration and distribution. It was found that sunscreens for specific ethnic groups need different combinations of UV filters, if a balanced relation between ultraviolet B (UVB) and ultraviolet A (UVA) protection is to be obtained. On the other hand, it could be demonstrated that the human skin is also well protected against visible and near-infrared light by melanin.
Conclusions: The higher the skin type category, the better the protection in the visible part of the spectrum of the sun. This stimulates the hot discussion at the present time, as to whether sunscreens should also contain protection compounds in the visible and near-infrared parts of the spectrum.     

Neuropeptide-E-1 Antagonizes the Action of Melanin-Concentrating Hormone on Stress-Induced Release of Adrenocorticotropin in the Rat

The physiological role of melanin-concentrating hormone (MCH) in mammals is still very elusive, but this peptide might participate in the central control of the hypothalamopituitary adrenal (HPA) axis during adaptation to stress. Cloning and sequencing of the rat MCH (rMCH) cDNA revealed the existence of additional peptides encoded into the MCH precursor. Among these peptides, neuropeptide (N) glutamic acid (E) isoleucine (I) arnide (NEI) is co-processed and secreted with MCH in rat hypothalamus. In the present work we examined: (1) The pattern of rMCH mRNA expression during the light and dark conditions in the rat hypothalamus and (2) The effect of intracerebroventricular (ICV) injections of rMCH and NEI in the control of basal or ether stress-modified release of corticotropin (ACTH), prolactin (PRL) and growth hormone (GH) secretion in vivo in light-on and light-off conditions. Our data indicate that rMCH mRNA levels do not change during the light-on period, but increase after the onset of darkness. Either alone or co-administered, rMCH and NEI do not modify basal secretion of GH and PRL at any time tested nor do they alter ether stress-induced changes in these two hormonal secretions. At the end of the light on period corresponding to the peak of the circadian rhythm in ACTH, administration of rMCH but not NEI leads to a decrease in ACTH levels while MCH is not effective during the light off period of the cycle (i.e. when basal ACTH levels are already low). Using a moderate ether induced stress, ACTH levels are only stimulated during the dark phase of the cycle. rMCH (63 or 210 nmoles) prevents the rise in ACTH release while NEI alone does not modify the stress response. Co-administration of both peptides before stress results in an abolition of the rMCH induced inhibition of ACTH plasma levels. Taken together, these data indicate that rMCH may act as a central corticotropin inhibitory factor involved in the circadian rhythmicity of plasma ACTH levels and that NEI antagonizes its action.     

Pigmented lateral periodontal cyst and other pigmented odontogenic lesions

OBJECTIVE: To report a case of lateral periodontal cyst (LPC) with marked melanin pigmentation in a 38-year-old Black male and to discuss the phenomenon of melanin pigmentation in odontogenic cysts and tumors.
RESULTS: Histologically, the epithelial lining of the LPC contained an abundant amount of melanin granules throughout the entire epithelium. Ultrastructurally, epithelial cells contained mature melanosomes (stage IV melanosomes). Melanophages containing aggregates of melanosomes were identified in the connective tissue cyst wall. Perusal of the literature revealed that melanin pigmentation in odontogenic lesions is uncommon. Melanin has been reported in calcifying odontogenic cyst (18 cases), odontogenic keratocyst (8 cases), adenomatoid odontogenic tumor (3 cases), ameloblastic fibroma (3 cases), odontoma (2 cases), and amelobastic fibro-odon-toma, odonto-ameloblastoma, and odontogenic fibroma (I case each).
CONCLUSIONS: Almost all pigmented odontogenic lesions occurred in Blacks and Asians; they are almost non-existent in Whites. Thus, racial pigmentation probably plays an important role in such lesions.     

The Tissue-Disposition of Gentamicin in Rats

Abstract: The tissue disposition of ¹⁴C-gentamicin was studied in young rats after a single-dose administration by autoradiographic techniques. The autoradiograms showed a high accumulation of the substance in non-parenchymateous tissues such as cartilages and connective tissues and a strong uptake in the kidney cortex. The in vivo bound substance was displaced from the cartilage at incubations in cation-containing solutions, indicating an ionic binding of the polycationic gentamicin to negatively charged groups in the cartilage (probably carboxyl and sulphate groups of chondroitin sulphate). In the inner ear a localization of the substance was found in the membraneous walls of the chochlea and, at short survival intervals, in the perilymph, whereas the radioactivity in the endolymph was low. Studies in vitro showed an ionic binding of gentamicin to cartilage and in addition to several other tissues, such as the lymphomyeloid system, the gastrointestinal mucosa, the exocrine pancreas, salivary glands, and most prominent, the pigmented tissues. A strong in vitro binding of gentamicin to pigment from beef eyes was also shown. The potential binding sites in the latter tissues are localized intracellularly and are therefore apparently unattainable for the charged hydrophilic gentamicin molecule in vivo.     

Incidence of a Latanoprost-Induced Increase in Iris Pigmentation in Japanese Eyes

Purpose

To prospectively determine the incidence of a latanoprost-induced increase in iris pigmentation in Japanese brown iris eyes by identifying changes in iris pigmentation on a series of iris color photographs.

Methods

In a cohort study, we prospectively and consecutively enrolled 104 patients (104 eyes) with primary open-angle glaucoma or normal-tension glaucoma who began treatment with latanoprost eye drops for the first time. None of the enrolled patients had a history of previous intraocular surgery or laser surgery. Patients comprised 51 men and 53 women. Their ages ranged from 23 to 80 years (mean ± SD, 63.8 ± 10.4 years). Before and every 3 months after starting latanoprost treatment, iris photographs were taken using a slit-lamp biomicroscope with an attached camera. To identify an increase in iris pigmentation, seven glaucoma specialists independently read the series of photographs. If five of the seven observers agreed that iris pigmentation had increased, we determined that the iris pigmentation had increased from the time the previous photograph was taken. Ten normal volunteers served as controls, and photographs of their eyes were used in the evaluation of iris pigmentation. The Kaplan-Meier life table analysis was adopted to evaluate the incidence of increase in iris pigmentation during treatment with latanoprost.

Results

The Kaplan-Meier life table analysis indicated that the incidence of increased iris pigmentation at 3, 6, 9, 12, and 15 months after the start of latanoprost treatment was 16.3%, 34.2%, 49.5%, 58.2%, and 58.2%, respectively.

Conclusions

Latanoprost instillation for at least 1 year induced increased iris pigmentation in approximately 50% of the treated Japanese eyes, which is a considerably higher percentage than that reported in Caucasians.?Jpn J Ophthalmol 2006;50:96–99 © Japanese Ophthalmological Society 2006     

清斑胶囊对ICR鼠皮肤色素生成及抗氧化作用的实验研究

目的：探讨清斑胶囊对黄体酮诱导的孕期全身色素加深小鼠血液和肝脏中的SOD、MDA、GSH的影响,以及对小鼠皮肤组织黑色素的影响。方法：制备黄体酮体内注射诱导小鼠全身色素加深模型,给药治疗后采用SOD、MDA、GSH试剂盒检测血清和肝脏中相关指标的变化;体外观察清斑胶囊对酪氨酸酶活性影响;免疫组化法观察对小鼠皮肤组织黑色素的影响。结果：清斑胶囊低中高三剂量组可以明显提高SOD、GSH活力,降低MDA含量;体外实验表明,清斑胶囊明显抑制酪氨酸酶活性,有效抑制皮肤组织黑色素的形成。结论：清斑胶囊具有良好的抗氧化作用及抑制小鼠皮肤黑素生成的作用。