METHYLATION OF SUGAR MERCAPTALS: II. L-ARABINOSE DIETHYL MERCAPTAL

Methylation of L-arabinose diethyl mercaptal in tetrahydrofuran with methyl iodide and silver oxide yielded mainly 2-O-methyl-L-arabinose and a trace of 5-O-methyl-L-arabinose. The identity of the major component was inferred by its behavior on electrophoresis and confirmed by the preparation of the crystalline amide. The polymethylated components were not examined. 2-O-Methyl-L-arabono-γ-lactone, previously known as a sirup, has now been obtained crystalline.

THE SYNTHESIS OF 5-O-METHYL-L-ARABINOSE

5-O-Methyl-L-arabinose is thought to occur in the hydrolysis products of methylated wheat bran hemicellulose. This sugar has now been synthesized from ethyl 2,3-di-O-acetyl-5-O-trityl-α-L-arabinoside by detritylation, methylation, and hydrolysis. The free sugar was obtained as a sirup and was characterized by periodate oxidation together with the preparation of a crystalline osazone and a crystalline lactone.

Immunohistochemical studies on dust mite antigen in positive reaction site of patch test

We demonstrated that eczematous reactions could be induced by patch testing with mite antigens in the majority of patients with atopic dermatitis (AD). By using immuno-double labelling technique, many mite antigen-bearing Langerhans cells were seen in the epidermis in the early stage of the patch testing. Twenty-four hours later, these cells were observed only in the deep dermis. Immunoelectron microscopically, it was found that the mite antigens were trapped by macrophages, which were apposing lymphocytes. On the other hand, we observed that Langerhans cells and Leu 3a positive cells in the AD lesions carried IgE molecules. Furthermore, many IgE-positive dendritic cells bearing mite antigen were seen in the positive patch testing sites. Taken together, IgE-mediated contact hypersensitivity to mite antigen may play an important role in the pathogenesis of AD.

Immunohistochemical localization of desmosomal and cytoskeletal proteins in the epidermis of healthy individuals and patients with Hailey-Hailey's disease

We have studied the immunohistochemical localization of desmosomal and cytoskeletal proteins in the epidermis of healthy individuals and patients with Hailey-Hailey's disease. It was found that the localization of desmosomal proteins (desmoplakin, desmoglein) and keratin filaments in the involved epidermis of patients with Hailey-Hailey's disease was almost same as that in the normal epidermis of healthy individuals. In contrast, the localization of actin filaments in the involved epidermis of patients with Hailey-Hailey's disease differed from that in the normal epidermis of healthy individuals.