Diffuse and focal palmoplantar keratoderma can be caused by a keratin 6c mutation.

The palmoplantar keratodermas (PPKs) are a large group of genodermatoses comprising nearly 60 genetically distinct diseases. They are characterized by hyperkeratosis on the palms and soles with or without extrapalmoplantar hyperkeratotic lesions. Focal PPK is one of the hallmarks of pachyonychia congenita, a rare autosomal dominant disorder resulting from mutations in the keratin genes KRT6A, KRT6B, KRT16 or KRT17. Recently, in-frame deletion mutations of KRT6C have been identified in three families with focal PPK with slight or no nail changes. We report here a novel KRT6C mutation identified in a Japanese family with PPK with phenotypic heterogeneity, presenting with not only focal but also diffuse hyperkeratosis. The proband had diffuse hyperkeratosis on the soles and small focal hyperkeratoses on the palms, while the two other affected individuals showed focal hyperkeratoses on the soles. All three patients were heterozygotes for c.1414G>A in KRT6C, predicted to result in p.Glu472Lys. These findings strongly suggest that screening of patients with nonepidermolytic diffuse PPK, in whom the pathogenic mutations are yet to be determined, might identify mutations in KRT6C.

Highly selective aldose reductase inhibitors. II. Optimization of the aryl part of 3-(arylmethyl)-2,4,5-trioxoimidazolidine-1-acetic acids.

Accumulation of intracellular sorbitol, the product of glucose reduction catalyzed by aldose reductase (AR) [EC 1.1.1.21], is thought to be the main culprit in the development of diabetic complications. A series of 3-arylalkyl-2,4,5-trioxoimidazolidine-1-acetic acids was prepared and tested for inhibitory activities towards AR and aldehyde reductase (ALR) [EC 1.1.1.2]. These derivatives showed strong inhibitory activity against AR without markedly inhibiting ALR. In particular, the compounds with 3-nitrophenyl, 4-chloro-3-nitrophenyl, and chloro-substituted benzothiazolyl groups as the aryl part showed powerful AR-inhibitory activity. The chloro-substituted benzothiazolyl compound showed an AR selectivity of more than 5,000 fold.

Highly selective aldose reductase inhibitors. 1. 3-(Arylalkyl)-2,4,5-trioxoimidazolidine-1-acetic acids.

A series of 3-(arylalkyl)-2,4,5-trioxoimidazolidine-1-acetic acids (1) was prepared and tested for aldose reductase (AR) and aldehyde reductase (ALR) inhibitory activities. These compounds showed strong inhibitory activity against AR without significant inhibitory activity for ALR. The ratio of IC50(ALR)/IC50(AR) was > 1000 in some compounds. On the basis of pharmacological tests such as the recovery of reduced motor nerve conduction velocity and toxicological profile, 3-(3-nitrobenzyl)-2,4,5-trioxoimidazolidine-1-acetic acid (NZ-314) was selected as the candidate for clinical development.

Sialyl cholesterol enhances the development of grafted neurons and motor recovery.

Trophic actions of alpha-sialyl cholesterol (SC) and its sialidase-tolerant derivative, alpha-(3 beta-hydroxysialyl) cholesterol (SCt), were carried out on the development of midbrain neurons both in vitro and in vivo transplantation studies. Low to moderate concentrations of SC (0.01 to 0.05 micrograms/ml) facilitated neurite extension but had no effects on cell survival of primary cultured midbrain neurons. However, high concentration of SC (0.1 micrograms/ml) disturbed both neurite genesis and cell survival. SCt had a similar effect on midbrain neurons. At higher concentrations, SC and SCt induced concentration-dependent morphological changes in astrocytes from flat to fibrous. The effect on astrocytes was stronger in SCt than SC. At highest concentration tested (20 micrograms/ml), the proliferation of astrocytes was completely blocked, cells became detached and finally died. This effect of SC and SCt was partially blocked by simultaneous application of aFGF. Following dopaminergic cell grafting in vivo, SC and SCt had biphasic effects: a low dose (0.2 mg/kg, SC) enhanced motor recovery at 4 and 6 weeks after transplantation, while the highest dose (20 mg/kg, SC) disturbed motor recovery at all periods tested. These effects on motor recovery were paralleled by an effect on neurite genesis as studied by tyrosine hydroxylase immunostaining. Thus, at low concentrations, SC and SCt are neurotrophic agents that stimulate the development and differentiation of dopaminergic neurons.

3 beta-Hydroxysialic acid glycosides. I. Calcium-binding ability and chemical and enzymatic stabilities.

Methyl alpha- and beta-glycosides of N-acetylneuraminic acid (Neu5Ac) and N-acetyl-3 beta-hydroxyneuraminic acid (Neu5Ac beta 3OH) (1-4) were prepared to evaluate their calcium-binding ability. (Methyl alpha-glucopyranosidonyl) alpha- and beta-, and 4-methylumbelliferyl alpha-glycosides of Neu5Ac and Neu5Ac beta 3OH (5-10) were also synthesized for the comparison of chemical and enzymatic stabilities, respectively. Methyl beta-glycosides of Neu5Ac and Neu5Ac beta 3OH, 3 and 4, respectively, showed intense calcium-binding abilities, while no such ability was observed in the corresponding alpha-glycosides, 1 and 2. The Neu5Ac beta 3OH glycosides, 6, 8, and 10, showed much stronger resistance to acidic hydrolysis and sialidase digestion than the corresponding Neu5Ac glycosides, 5, 7, and 9.

Effect of Neurotropin on the activation of the plasma kallikrein-kinin system.

Bradykinin (BK), an important mediator of allergic reactions and pain induction, is released by the activation of the plasma kallikrein-kinin (K-K) cascade. Neurotropin is a biological material obtained from inflamed rabbit skin inoculated with vaccinia virus and is widely used clinically in Japan as an effective agent for these disorders. Since its mechanism of action is not clearly known, we have investigated the effects of Neurotropin on the human plasma K-K system. In dextran sulfate-activated plasma, Neurotropin inhibited the formation of BK, the cleavage of high molecular weight kininogen (HK) and the formation of kallikrein-C1 inhibitor and activated coagulation factor XII (FXIIa)-C1 inhibitor complexes. Experiments using purified enzyme of the K-K cascade indicated that Neurotropin inhibited surface-mediated activation of coagulation factor XII (FXII) and the activation of prekallikrein by FXIIa. Neurotropin also inhibited the binding of FXII and HK to the activating surface. These data suggest that the ameliorating effects of Neurotropin in allergic disorders and pain syndromes may be related to this ability to inhibit activation of the K-K cascade and consequently the formation of BK.

Simple method for determination of A1c-type glycated hemoglobin(s) in rats using high performance liquid chromatography.

We have developed a new chromatographic method for the determination of rat glycated hemoglobins by cation exchange high-performance liquid chromatography. The hemoglobins were eluted by a two-step gradient, and the total assay time, including re-equilibration of the column, was 27 min. Two A1c type and one pre-A1c type rat glycated hemoglobins were separated and measured. The change in major HbA1c of rats, in which diabetes was induced by streptozotocin and which were subsequently treated with insulin, was monitored. In diabetic rats (n = 10, average blood glucose greater than 300 mg/dL), major HbA1c rose to 3.39 +/- 0.06% compared with controls (n = 10, 1.20 +/- 0.03%) during 5 wk. Insulin treatment decreased the HbA1c from 3.48 +/- 0.16% to 2.74 +/- 0.15% (p less than 0.01) in 6 wk. This method was also effective for the determination of mouse HbA1c.

Study on the in vitro assay method for evaluating the inhibitory effect of various substances on the production of plasma kallikrein.

The assay method based on the principle of kallikrein-kinin cascade was established for evaluating the inhibitory effects of various substances on the production of plasma kallikrein. In this in vitro assay, it was found that indomethacin, ketoprofen, ibuprofen and an extract obtained from inflamed rabbit skin inoculated with vaccinia virus (NSP) had the inhibitory effect on the production of plasma kallikrein. Kinins generated in the reaction mixture were measured by RIA. It was shown that the generation of kinins was also inhibited by these substances. From these results, it is hoped that this assay method may be useful for screening the substances which inhibited the production of kinin.