自体移植皮片中黑皮素1受体表达与黑色素含量的相关性研究

目的检测黑皮素1受体(melanocortin 1 receptor,MC-1R)及黑色素在不同类型自体移植皮片中的表达,并与自身正常皮肤作对照,初步认识MC-1R在自体移植皮片过度色素沉着中的作用。方法取颈部自体皮片移植术后1年的皮片(包括全厚皮片、中厚皮片及刃厚皮片),以及原供区、受区周围皮肤作为正常对照,采用免疫组织化学方法、银染-丽春红法检测自体移植皮片与正常皮肤中MC-1R表达及黑色素含量。结果MC-1R的表达定位于表皮基底部黑色素细胞、角质形成细胞胞浆;在各类自体移植皮片中均呈阳性表达,皮片愈薄MC-1R表达愈明显;MC-1R在各类移植皮片中的表达与两类正常对照皮肤比较差异均有统计学意义(P<0.01),但两类正常对照皮肤内的表达差异无统计学意义(P>0.01)。不同类型移植皮片表皮中黑色素含量较两种正常对照皮肤均明显增加,且差异有统计学意义(P<0.01);且不同类型移植皮片表皮中黑色素含量的差异亦均有统计学意义(P<0.01),皮片愈薄,黑色素含量愈多;皮片中黑色素含量与MC-1R表达量呈正相关。结论自体移植皮片中黑色素含量与MC-1R表达量呈正相关,MC-1R在自体移植皮片中的高表达能使皮片中黑色素含量增加,在自体移植皮片过度色素沉着中起重要调控作用。     

产黑素培养基在新生隐球菌病诊断和预后评估中的临床意义

目的:寻找新生隐球菌病的临床快速诊断方法和临床预后的评估指标.方法:用咖啡酸玉米吐温和多巴(CT)两种产黑素培养基培养128株已被明确鉴定的新生隐球菌,并以白念珠菌等作对照,25℃生长,了解显色结果.结果:非新生隐球菌及一部分新生隐球菌在两种培养基中均不显色,有12株新生隐球菌病仅在一种培养基中显色,2株临床分离株在两种培养基上均不显色.结论:产黑素培养基在新生隐球菌病的快速诊断和临床预后评估中均可起重要的作用.     

Recent advances in genetic analyses of oculocutaneous albinism types 2 and 4

Patients with OCA are characterized by reduced skin and hair pigmentation and consequent photosensitivity, actinic damage and risk of skin cancer, and by reduced visual acuity and nystagmus. Our survey of Japanese patients revealed that OCA1 was the most frequent type at 34%, while type 2 was present at less than 10%. OCA3 was absent. OCA4, which is a rare type worldwide, was the second most frequent type at 27%. Unexpectedly 10% of the patients turned out to be Hermansky–Pudlak syndrome type 1. Furthermore, the pathogenic p.A481T allele for OCA2, which has 70% melanogenesis activity, was found in approximately 12% of normally pigmented people, indicating that sub-clinical OCA2 might be more frequent in the Japanese than currently thought. And OCA4 is one of the most common types in Japanese patients, despite being rare worldwide.     

Pigmented Papillary Carcinoma: A Rare Tumor of the Male Breast

Primary melanin pigment containing tumors of the breast are rare. We report a pigmented papillary carcinoma of a 60-year-old male patient who presented a firm mass 1.7 cm in diameter with an ill defined border on ultrasonography behind the mamilla. To the best of our knowledge this is the third case report of this type of tumor in male breast.     

Role of melanin in mechanical properties of Glycera jaws

The remarkable mechanical prowess of the jaws of the bloodworm Glycera dibranchiata appears to be a consequence of a robust cross-linked network of organic molecules, notably melanin and proteins, as well as small amounts of unmineralized Cu and a Cu-based mineral. The present study focuses on the role of melanin. Mechanical properties of untreated jaws and the constituent melanin are probed through nanoindentation, both in air and underwater. Complementary information is obtained from density and porosity measurements and attempts at Cu removal from the jaws using EDTA, an effective metal chelator in most biological systems. In near-tip regions of the jaws, mechanical properties attain the highest values and diminish only slightly when wet (by 15-25%), in contrast to the behavior of other organic biomaterials. The melanin constituent contributes significantly to the mechanical integrity of the jaw; its hardness and elastic modulus are about half those of untreated jaws. Although melanin may be the dominant shape-determining component of the structure, it remains to be shown whether jaw assembly is mediated by protein deposition on a melanin scaffold or, conversely, by melanin deposition on a protein scaffold. The inability of EDTA to chelate Cu from the jaws and the relatively high density of the jaws and the melanin support the notion of a highly cross-linked molecular structure. Finally, based on the metric H(3)/E(2) (H being hardness and E the Young's modulus), the results suggest that the abrasion resistance of the jaws is superior to all engineering polymers and competitive with the hardest metallic alloys.     

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。     

Irradiation of pigmented melanoma cells with high intensity pulsed radiation generates acoustic waves and kills cells

Photokilling of pigmented mouse melanoma cells (B-16) was investigated using pulsed high intensity visible radiation. Melanin acts as an endogenous chromophore, and 694 nm radiation with 40 nsec pulse duration and 0.5-3 X 10(7)w/cm2 intensity causes cell death. Irradiation of non-pigmented human melanoma cells (U1) or human squamous carcinoma cells (FaDu) under similar conditions did not kill the cells. Also, irradiation of B-16 cells with 300 microsec laser pulses (10(3)W/cm2) or with continuous wave (CW) radiation (10(-3)W/cm2) did not kill the cells. These data indicate that pigmented cell killing is due to absorption of radiation by melanin and that the pulsewidth and intensity of radiation play important roles in cell killing. The generation of acoustic waves due to absorption of the pulsed radiation by pigmented cells and by isolated melanosomes was demonstrated at 532 and 625 nm and 8.5 nsec pulse duration (10(7)-10(8) W/cm2); the amplitudes of the acoustic signals were approximately 2.5-3.0-fold higher at 532 nm compared with 625 nm, and they increased with increasing fluence. In contrast, irradiation of U1 or FaDu cells with comparable fluences and intensities did not generate acoustic waves. A possible correlation between the generation of photoacoustic waves and pigment cell death is proposed. Since the thermal relaxation time of melanosomes is 0.5-1.0 microsec, the mechanism proposed is that thermal confinement of high intensity, short-pulse visible radiation generates acoustic waves by thermal expansion, leading to mechanical damage to the cells.     

Pigmented astrocytoma with suprasellar location: case report and literature review

A large suprasellar, partly cystic, contrast-enhancing tumor was resected from a 19-year-old woman who presented with bitemporal visual field defects and reduced visual acuity. Grossly, the tumor was brown and located in the subarachnoid space. Histologically, it was composed of spindle and pleomorphic cells, including giant tumor cells, with markedly pleomorphic nuclei. Reticulin fibers surrounded single cells and small groups of cells. Very few mitotic figures were found in the tumor, and no necrosis or microvascular proliferation was seen. The tumor thereby resembled a pleomorphic xanthoastrocytoma. Many of the tumor cells contained a dark-brown intracytoplasmic pigment, shown to be melanosomal melanin by ultrastructural examination. Immunohistochemical examination demonstrated that the pigment was present in glial tumor cells. Only four cases of pigmented astrocytic tumors have been published, none of these were suprasellar. Our patient received fractionated radiotherapy with a total dose of 48.6 Gy 14 months after gross total removal of the tumor. She is alive without relapse after 12-year follow-up.     

Protection of melanoma cells against superoxide radicals by melanins

Summary Human melanoma cells transplanted into immunocompetent mice by the 6-day subrenal capsule technique are characterized by high resistance against immunological attack. This resistance is suggested to be the consequence of scavenging of superoxide free radicals by melanin. Scavenging of superoxide radicals by the melanoma cells was clearly demonstrated using electron spin resonance techniques. From comparison with synthetic melanins it is concluded that the scavenger effect can be attributed mainly to low-molecular-mass melanins synthesized in the melanoma cells whereas high-molecular-mass melanins are practically ineffective.Abbreviations ESR electron spin resonance - DMSO dimethylsulfoxide - TEMPOL 2,2,6,6-tetramethyl-4-hydroxypiperidine-1-oxyl     

Characterization of a naturally occurring protease inhibitor in the hemolymph of the scorpion, Heterometrus bengalensis.

A protease inhibitor has been purified by ultracentrifugation, affinity chromatography on trypsin-sepharose 4B, and chromatofocusing on PBE-94 from hemolymph of the scorpion Heterometrus bengalensis. Homogeneity of the protease inhibitor was demonstrated by high performance liquid chromatography (HPLC). The protease inhibitor is a monomeric glycoprotein with a molecular weight of 120,000 dalton, which is stable between pH 4 and pH 8. The molecule inhibits serine proteases like trypsin and -chymotrypsin and shows a noncompetitive mode of inhibition towards trypsin, with a Ki value of 6.1 × 10⁻⁶ mM. Amino acid analysis shows a preponderance of aspartic acid, glutamic acid, serine, and glycine. The protease inhibitor is efficient in inhibiting phenoloxidase activity in both the hemolymph and the isolated phenoloxidase. Melanin synthesis by phenoloxidase may be influenced by this protease inhibitor.