Impaired interleukin-2 production in T-cells from a patient with Wiskott-Aldrich syndrome: basis of clinical effect of interleukin-2 replacement therapy.

Interleukin-2 production may be one of the underlying causes of Wiskott-Aldrich syndrome immunodeficiency and recombinant interleukin-2 administration (or an infusion of T-cells expanded by CD3 stimulation and rIL-2) is able, to some extent, to restore defective T-cell function.

Hepatitis C virus infection in a patient with dermatomyositis and left ventricular dysfunction.

Hepatitis C virus (HCV) infection is frequently associated with autoimmune disease. We present here a case of dermatomyositis manifested as heart failure in which HCV was detected from an endomyocardial biopsy sample. HCV infection may have contributed to the left ventricular dysfunction in this patient with dermatomyositis.

Spitz nevus on the palmar surface.

Relatively little is known about the incidence of Spitz nevus on palmar surfaces. This report places a case study in the context of the Japanese literature regarding the occurrence of Spitz nevus on palmar surfaces. Although the proportion of palms and soles in relation to the body surface is about 5%, the incidence of the Spitz nevus was 2%. The mean age at onset was 17.8 years, and all 4 cases were women. The clinical features were a black macule or flatly elevated small modules. The size of the lesions was relatively small, extending from 3.5 mm to 8.0 mm. Although the backs of the hands and insteps have almost the same area as the palms and soles, the incidence of onset in these regions was 6.3% (13 cases). We thus concluded that Spitz nevus tends to be rare on palms and soles.

Hyperpigmentation caused by hyperthyroidism: differences from the pigmentation of Addison's disease.

Two cases of hyperthyroidism with hyperpigmentation are presented. In both cases, hyperpigmentation was seen on the lower extremities, most strikingly on the shins, backs of the feet and the nail bed. Histology of the pigmented skin showed basal melanosis and heavy deposition of haemosiderin around dermal capillaries and sweat glands. Treatment with mercazol in both cases resulted in no significant waning of pigmentation. Distribution of hyperpigmentation, haemosiderin deposition and poor response to the treatment may be characteristic features of the pigmentation caused by hyperthyroidism, and may represent differences from the pigmentation seen in Addison's disease.

Efficient production of a small peptide by expression as a multimeric form fused with the dihydrofolate reductase affinity handle.

A pentapeptide which potently inhibits primary IgE antibody formation, Asp-Ser-Asp-Gly-Lys (DSDGK), has been efficiently produced with the aid of the dihydrofolate reductase (DHFR) handle [M. Iwakura, et al. (1992) J. Biochem. 111, 37-45]. The genes coding fused proteins comprising DHFR and multimeric forms of DSDGK, namely, DHFR-(DSDGK)3, DHFR-(DSDGK)14, and DHFR-(DSDGK)28, were constructed and expressed in Escherichia coli. The C-terminal peptides attached to DHFR did not affect the expression or the function of the DHFR handle, even when the length of the C-terminal peptide was as long as 160 amino acid residues. The fused proteins were easily purified by methotrexate affinity chromatography, one of the major advantages of the DHFR handle. The fused proteins were digested with trypsin and the monomeric peptide, DSDGK, was purified by HPLC. The yields of the peptide were estimated to be 11, 43, and 99 mg per 1 gram of the total cell proteins from E. coli cells producing DHFR-(DSDGK)3, DHFR-(DSDGK)14, and DHFR-(DSDGK)28, respectively.

Voltage-gated anion channel of the electric organ of Narke japonica incorporated into planar bilayers.

Voltage-gated anion channels in vesicles prepared from the electric organ of Narke japonica were studied using two methods. Ionic permeability was measured by the light scattering method, which could be used to measure the ion permeation of whole vesicles but only at a time scale of slower than about 0.1 s. The single channel conductances and permeability ratios for various ions were measured after fusing the vesicles to phospholipid bilayers. Both sets of results coincided, indicating that the anion channels observed with the planar bilayer method are the major route for anion passage in these vesicles. The channels showed anion selectivity and did not allow the permeation of cations such as K+ and choline+. The single channel conductance was 18 pS in 0.1 M Cl-. SCN- inhibited the conductance in a voltage-dependent reversible manner on both sides of a channel. SCN- may bind to the Cl- binding site in a channel and thus block it. 4,4'-Diisothiocyanostilbene-2,2'-disulfonic acid (DIDS) blocked a channel on the cis (extracellular) side irreversibly. The number of anion channels per vesicle was estimated to be about 50. It was also shown that all anion channels in the vesicles were open at the very instance of fusion with planar membranes.