Melanogenesis, or synthesis of melanin has been a focus of intense investigation by pigment cell biologists during the past few decades. Melanogenesis provides pigment in skin, thus serving as a unique, if not only, physiological defense against sun-induced injuries, including photocarcinogenesis. Moreover, skin color plays a major role in visual esthetics of an individual. Therefore, unwanted hyper- or hypo-pigmentation, especially on facial skin, could cause significant psychological stress. Epidermal melanocytes, derived from neural crest cells, are mainly responsible for melanin in skin. In human skin, nearly all normal pigmentation is due to melanin and with the exception of hemoglobin, it is one of the only endogenously synthesized pigments in man. Melanin has numerous functions in mammals, including increasing the optical efficiency of the eye, producing color patterns in various organs, including hair or skin, serving as camouflage, heat exchange, sexual recognition and protection from sunlight. The incidences of malignant melanoma have been increasing dramatically in western countries, at least by a factor of 15 over the past 60 years, and this has caused an intense interest in understanding melanogenesis. More than 40,000 new cases of malignant melanoma have been diagnosed in 1997, and it is one of the most common cancers in young adults. The research in the area of melanogenesis has exploded during the last ten years because model systems to study molecular mechanisms regulating melanogenesis have become available. This review examines currently available in vitro and in vivo model systems to study melanogenesis.
Esthetics ; Hair ; Hot Temperature ; Humans ; Incidence ; Mammals ; Melanins ; Melanocytes ; Melanoma ; Neural Crest ; Pigmentation ; Skin ; Stress, Psychological ; Young Adult

Granuloma pyogenicum is a benign vascular tumor, usually about 0.5 to 2cm in diameter. It occurs as a single lesion with few exceptions and consists of pedunulated nodule with a dull red or slightly purplish color. We observed a 29-year old man who had multiple satellite recurrences in the scapular region which developed after excision of a single lesion of granuloma pyogenicum. Histapathologic findings showed many newly formed capillaries that had prominant endothelial cells and showed varying degrees of dilation without appearance of epiderrnal collarette sign. The lesions were much improved by X-ray irradiation.
Adult ; Capillaries ; Endothelial Cells ; Granuloma* ; Granuloma, Pyogenic* ; Humans ; Recurrence ; Shoulder*

No abstract available.
Zygoma*

No abstract available.
Zygoma*

PURPOSE: The purpose of this study was to examine the effects of change of polyethylene resin type and manufacturing method on the wear of polyethylene tibial component. MATERIALS AND METHODS: Thirteen MG I and 10 MG II components were retrieved at revision surgery. Each polyethylene tibial component was graded for surface wear damage. Density profiles of the polyethylene were measured to examine the extent of oxidative degradation of the polyethylene. RESULTS: The primary damage mode of the MG I retrievals was scratching and metallic debris, but the primary damage mode of the MG II was delamination (P<0.05). For the implants with implantation time of 5 years or more, the MG II polyethylene had a higher density value (0.959+/-0.002 g/cc, n=7) compared with the MG I (0.948+/-0.004 g/cc, n=11). Both delamination and polyethylene degradation increased with length of implantation time for the MG II components (P<0.01). Even after gamma sterilization, the directly molded 1900 MG I components experienced significantly less delamination and degradation than the machined GUR 415 MG II tibial components. CONCLUSIONS: This study suggests that delamination of polyethylene tibial components is influenced by resin type and/or manufacturing method
Fungi ; Polyethylene* ; Sterilization

Nucleolar organizer regions are DNA loops encoding rihbosomal RNA production and detectable by the argyrophilia of their associated proteins(AgNORs). AgNOR numbers correlate with cellular proliferating activity. Many studies have shown a significnt difference in AgNOR counts between benign and malignant tumors. AgNOR counts were also helpful in differential diagnosis. For the evaluation of its diagnostic utility in gastric lesions, a silver staining technique was carried out in paraffin sections of 5 control cases, 5 benign peptic ulcers, 7 hyperplastic polyps, 10 tubular adenomas, 16 early gastric adenocarcinomas and 15 advanced gastric adenocarcinomas. The results were as follows. The mean numbers of AgNORs in early and advanced gastric adenocarcinomas(1.94 and 2.16) were significantly higher than those of normal foveolar epithelium(1.43) and epithelia of benign gastric ulcers(1.54), hyperplastic polyps(1.64) and tubular adenomas(1.79). In malignancy, there was increased variability in size and shape of AgNORs. There was little differences in mean AgNOR numbers between early and advanced gastric adenocarcinomas. Differentiation of the tumor made no difference in AgNOR numbers. From the above results, the AgNORs count, if its morphologic change are taken into consideration, is helpful in differentiation between malignant and non-malignant lesions.
Diagnosis, Differential ; Adenocarcinoma

Angiofollicular lymph node hyperplasia(AFLNH) was first described in 1956 by Castleman et al. It was initially reported as a solitary mediastinal mass but multicentric and extranodal disease is now well known. Histologically two distinct variants, e.g. the hyaline vascular type and the plasma cell type, of AFLNH are recognized. And the plasma cell type is typically associated with clinical syndrome consisting of fever, anemia, elevated erythrocyte sedimentation rate and polyclonal hypergammaglobulinemia. Recently, we experineced three cases of AFLNH. Histologically, two cases were hyaline vascular type, that were presented as a right supraclavicular mass of 49-year-old female, and as an anterior mediastinal mass of 53-year-old female. The remaining one case was plasma cell type that was presented as a left axillary mass of 63-year-old male. The former two cases showed typical features of hyaline vascular type but in case 1, exuberant proliferation of hyalinized vessels of capillary size was characteristic feature. The latter case of plasma cell type characteristically showed clinical syndrome consisting of fever, hypoalbuminemia, polyclonal hypergammaglobulinemia. All cases were presented as a single mass and they were well after surgical excision.
Female ; Humans

No abstract available.
Carcinoma, Papillary* ; Thyroid Gland*

Gene expression of nm23 has been investigated in many kinds of tumors, including breast cancers, colon cancers, hepatocellular carcinomas, papillary carcinomas of the thyroid and malignant melanomas since the nm23 was dislovered by Dr. Steeg as a tumor metastatic suppressor gene. Reduced expression of nm23 gene implicated in high metastatic potential in a variety of malignancies. However, there have been only a few reports on genetic alteration and expression of nm23 in human gastric carcinomas even though gastric carcinoma is a leading malignancy in Korea. In this study, we examined the expression of nm23 protein by immunohistochemistry in advanced and early gastric carcinomas, adenomas, matching normal mucosa to elucidate the role of nm23 in the development, progression and metastasis of human gastric carcinomas. The results are as follows; 1) Nm23 was expressed in 39 cases(69.6%) of 56 advanced gastric carcinomas. Among them, strong positive cases(grade 3) were 26(46.4%) and weak positive cases(grade 2) were 13(23.2%). 2) Nm23 expression was significantly different (P<0.05) depending on the site of the neoplasm. Antral carcinomas showed grade3 positivity in the 22/37 cases(60%), but carcinomas of the body showed negative (grade 1) result in about half(42.1%). 3) Nm23 expression was more intense in the neoplasm than normal mucosa.(67.9%) 4) Nm23 expression was not significantly related to the lymph node metastasis, invasion of lymphatics or veins and depth of invasion. 5) In the well differentiated carcinomas, grade3 were more common(64.0%). But in cases of signet ring cell carcinoma, many cases were negative(50.0%). 6) Nm23 expression rate and intensity was significantly increased from the normal mucosa to the gastric adenomas, early gastric carcinomas and advanced gastric carcinomas.
Humans ; Carcinoma, Hepatocellular ; Neoplasm Metastasis ; Breast Neoplasms

BACKGROUND: Several methods have been developed to measure skin thickness, including the use of the radiography, micrometer screw gauge, Harpenden's caliper, and ultrasound, but there are no reports to measure skin thickness using computed tomography. OBJECTIVE: We measured skin thickness on the CT films retrospectively. This study was to investigaste variations of skin thickness by age, gender, and different sites. METHODS: Skin thickness was measured on the CT films of 562 patients, including 357 males and 205 females who had undergone brain, chest, and abdominal CT in our hospital. Patients with endocrinologic, malignant, or collagen disease and those on antimetabolite or steroid therapy were excluded. Comparisons of histometric and computed tomographic methods weremade in 5 skin tumors and 1 localized lipodystrophy. Results: 1. The measurements of the skin thickness(mean) in examined sites varied from 0.84 to 3.07 milimeters : the posterior part at the level of the chest(aortic arch level) was the thickest and the anterior part at the level of the forehead(aortic arch level) was the thickest and the anterior part at the level of the forehead(frontal sinus level) was the thinnest. 2. Skin thickness in males wal generally thicker than in females : the anterior and lateral part at the level of the forehead(P<0.0001), the posterior part at the level of the bladder(P<0.2) were thicker in males than in females. 3. In each gender, the thickness of the skin increased with age of 40 or 60, and then decreased with age at every level. 4. Skin on posterior parts of the body was thicker than on other parts. 5. Unlike other levels, skin was thicker on the lateral parts than on the anterior parts at the levels of the forehead and bladder. 6. The measured skin thickness in about 7% greater in formalin fixed tissues than on CT films. CONCLUSION; Computed tomographic measurement of the skin thickness in a reliable method in the aquisition of normal values and their individual variations during cutaneous aging. Moreover, this method is useful in evaluating skin tumors and monitoring the response to therapy of inflammatory conditions.
Aging ; Brain ; Collagen Diseases ; Female ; Forehead ; Formaldehyde ; Humans ; Lipodystrophy ; Male ; Radiography ; Reference Values ; Retrospective Studies ; Skin* ; Thorax ; Tomography, X-Ray Computed ; Ultrasonography ; Urinary Bladder