Sumiko Hamanaka

Glucosylceramide accumulates preferentially in lamellar bodies in differentiated keratinocytes

Background  Sphingolipids, e.g. ceramide (Cer), glucosylceramide (GlcCer) and sphingomyelin (SM), are important bulk constituents of plasma membranes in mammalian cells. In addition, these lipids are also enriched in certain intracellular organelles, as well as in the epidermal lamellar bodies (LBs) of differentiating keratinocytes (KCs). Epidermal Cer, which comprises a heterogeneous family of at least 10 members, is a key component of the stratum corneum (SC) lipids, and regulates permeability barrier function. Levels of GlcCer, but not SM, significantly increase during epidermal differentiation, and then both GlcCer and SM are enzymatically hydrolysed to Cer at and just above the transition from the stratum granulosum to the SC.

Tumor Necrosis Factor-α Stimulates the Production of Squamous Cell Carcinoma Antigen in Normal Squamous Cells

Squamous cell carcinoma (SCC) antigen, a tumor marker of squamous cell carcinoma, is also increased in several nonmalignant skin lesions, e.g. pemphigus. The aim of the present investigation was to determine if tumor necrosis factor-alpha (TNF-alpha), one of the important environmental factors, stimulated the production of SCC antigen in the normal squamous cells. The exposure of normal human epidermal keratinocytes to TNF-alpha (100 IU/ml) for 72 h greatly increased the SCC antigen production. The stimulatory effect of TNF-alpha (1,000 IU/ml) on the production of SCC antigen was also observed in the normal squamous epithelium tissue. These results would be helpful for understanding the increase of SCC antigen in several nonmalignant skin disorders.

Porokeratosis large skin lesions are susceptible to skin cancer development : histological and cytological explanation for the susceptibility

Porokeratosis (PK), an autosomal dominant inherited skin disorder, is known to develop malignant skin tumors on its skin lesions. Our recent literature survey has revealed that large PK skin lesions are frequently a precursor of malignant changes. In the study, large and small PK skin lesions were investigated in terms of histological features of the epidermis and of the cellular DNA content of epidermal cells. Large PK lesions frequently showed hypertrophic epidermis with many epidermis without such mitotic cells. Abnormal cells, like those containing hyperchromatic, large, and/or irregularly shaped nuclei, were present in the epidermis of both large and small lesions with a preponderance in the former over the latter. DNA polyploidy was seen more frequently in large PK lesions than in small ones. DNA index values were significantly higher in large lesions than in small ones. The histological features and DNA ploidy abnormalities probably reflect the higher proliferation and the greater potential for malignant changes of large PK skin lesions. Our study helps to explain the clinical evidence that large PK skin lesions are frequently a precursor of malignant skin tumors.

Structure determination of glycosphingolipids of cultured human keratinocytes

From cultured human keratinocytes, seven glycolipid fractions were isolated by DEAE and silica-gel column chromatographies, and further by HPLC on a silica-gel column. By means of 1H-NMR spectroscopy, fast atom bombardment mass spectrometry and GLC-mass spectrometry, one fraction was determined to contain acylglucosylceramides, which consist of amide linked omega-hydroxy fatty acids (C30:0, C30:1, C32:1 and C34:1), fatty acids linked to the omega-hydroxy fatty acids through ester linkages (C14:1, C16:1, C18:1 and C18:2), a long-chain base (d18-sphingenine), and beta-glucose. Five of the other fractions contained glucosylceramides, and the seventh fraction contained a mixture of glucosylceramides and galactosylceramides. Glucosylceramides containing long-chain omega-hydroxy fatty acids, which are assumed to be immediate precursors of the acylglucosylceramides, were hardly detected in these glycolipid fractions. Six glucosylceramide fractions were separated due to differences in their fatty acids and sphingosines. On comparison with the results reported in our previous paper, the acylglucosylceramide content of the cultured human keratinocytes was about half that of human epidermis. Under the culture conditions used, the human keratinocytes did not differentiate into granular or horny cells. Taken together, the results suggest that the synthesis of acylglucosylceramides is not activated much in the cultured keratinocytes, but would be more activated in differentiated cells.

Lipid composition and fatty acid analysis ofHelicobacter pylori

Lipids extracted fromHelicobacter pylori were separated into lipid classes by thin-layer chromatography. SimpleH. pylori lipids consisted of cholesterol esters, triglycerides, free fatty acids, cholesterol, diacylglycerols, and monoacylglycerols. Fatty acids were released from each lipid class by acid methanolysis, and analyzed by gas liquid chromatography and mass spectrometry. Unique methoxy fatty acids, including 11-methoxy heptadecanoic and 11-methoxy nonadecanoic acids, were the major components of the cholesterol esters and triglycerides. The predominance of methoxy fatty acids in the cholesterol esters ofH. pylori may contribute to the acid-resistant characteristic of this bacillus.

Multiple Malignant Eccrine Poroma and a Linear Epidermal Nevus

A 68‐year‐old woman developed three reddish nodules on a linear epidermal nevus on the right arm. The nodules and linear lesion were resected. The histology revealed the two larger nodules to be eccrine porocarcinoma and the other to be eccrine poroepithelioma. The linear lesion was actually epidermal nevus. To our knowledge, this is the first description of adnexal tumors developing on epidermal nevus.

Leiomyoblastoma and Leiomyomatosis of the Small Intestine in a Case of von Recklinghausen's Disease

A 70‐year‐old patient with von Recklinghausens neurofibromatosis 1 (NF1) developed a stomach ulcer and underwent a total gasterectomy. During the laparotomy, a leiomyoblastoma and multiple leiomyomas, which were histologically diagnosed as such later, were found in the small intestine and resected. It is quite possible that the association of gastrointestinal leiomyomas and NF1 is more than coincidental. It is thus important to take this complication into account in clinical treatment of patients with NF1.

Tissue accumulation of sulfatide and GM3 ganglioside in a patient with variant Farber disease

We analyzed the lipids in the tissues of a patient with an atypical form of Farber disease who developed several clinical symptoms not seen in patients with typical Farber disease (acid ceramidase deficiency). Lipids were extracted from formalin-fixed brain, liver and kidney and purified by ion exchange and silica gel column chromatographies and further by high-performance liquid chromatography on a silica gel column. We performed structural and quantitative analyses of three lipids named lipids X, Y and Z. Lipid X accumulated in the liver but not in the brain. Accumulation of lipids Y and Z was observed in liver and kidney. The content of lipid Y in the patients liver was more than ten times that in a control. The structures of lipids X, Y and Z were confirmed by means of 1H-nuclear magnetic resonance spectroscopy, fast atom bombardment mass spectrometry, infrared absorption spectroscopy, and component analysis involving gas liquid chromatography and gas chromatography-mass spectrometry. The structures of lipids X, Y and Z were identified as those of ceramide, sulfatide and GM3 ganglioside, respectively. These results suggest two possibilities. One is that the accumulation of glycolipids such as sulfatide and GM3 ganglioside is a secondary event produced by the accumulation of ceramide due to ceramidase deficiency. The other is that the accumulation of glycolipids other than ceramide is due to a deficiency of sphingolipid activator proteins which may affect the degradation of sulfatide and GM3 ganglioside as well as ceramide.

Ganglioside antigen of DU‐PAN‐2 in a human pancreatic cancer

DU‐PAN‐2 reactive gangliosides were isolated from the tumor of a patient with pancreatic cancer (duct cell carcinoma, moderately differentiated adenocarcinoma), having a negative Lewis blood phenotype, and were analyzed by means of TLC‐immunostaining, enzyme‐linked immunosorbent assay (ELISA), permethylation study, 1H NMR spectroscopy and fast atom bombardment mass spectrometry. The structures of the gangliosides were found to be NeuAcα2‐3Ga1β1‐3G1cNAcβ1‐3Ga1β1‐4Glcβ1‐1′Cer, containing normal and hydroxy fatty acids. By TLC‐immunostaining and ELISA with chemically synthesized gangliosides, DU‐PAN‐2 was demonstrated to react strongly with IV3αNeuAc‐Lc4Cer, weakly with IV3αNeuAc‐nLc4Cer, and moderately with IV6αNeuAc‐Lc4Cer and IV6αNeuAc‐nLc4Cer. Thus it was concluded that the DU‐PAN‐2 reactive ganglioside in the tumor is IV3αNeuAc‐Lc4Cer and that DU‐PAN‐2 has a rather broad specificity.

A Case of Recessive X-Linked Ichthyosis : Scale-Specific Abnormalities of Lipid Composition May Explain the Pathogenesis of the Skin Manifestation

We analyzed the lipid content of the scales, red blood cells, and plasma from a recessive X‐linked icthyosis patient. The patients scales accumulated cholesterol sulfate, had decreased levels of free sterols, sterol esters and sphingolipids, and lacked phospholipids. Although the accumulation of cholesterol sulfate was found in the patients red blood cells and plasma as well as in the scales, other lipid composition abnormalities were specific for scales. Such scale‐specific abnormal lipid composition may explain the pathogenesis of generalized hyperkeratosis and abnormal scaling of the disease.