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The epidermal cornified cell envelope (CE) is a complex protein-lipid composite that replaces the plasma membrane of terminally differentiated keratinocytes. This lamellar structure is essential for the barrier function of the skin and has the ability to prevent the loss of water and ions and to protect from environmental hazards. The major protein of the epidermal CE is loricrin, contributing approximately 70% by mass. We have generated mice that are deficient for this protein. These mice showed a delay in the formation of the skin barrier in embryonic development. At birth, homozygous mutant mice weighed less than control littermates and showed skin abnormalities, such as congenital erythroderma with a shiny, translucent skin. Tape stripping experiments suggested that the stratum corneum stability was reduced in newborn Lor(-/-) mice compared with wild-type controls. Isolated mutant CEs were more easily fragmented by sonication in vitro, indicating a greater susceptibility to mechanical stress. Nevertheless, we did not detect impaired epidermal barrier function in these mice. Surprisingly, the skin phenotype disappeared 4-5 d after birth. At least one of the compensatory mechanisms preventing a more severe skin phenotype in newborn Lor(-/-) mice is an increase in the expression of other CE components, such as SPRRP2D and SPRRP2H, members of the family of "small proline rich proteins", and repetin, a member of the "fused gene" subgroup of the S100 gene family.

It is known that a high incidence of hepatocellular carcinoma in rat liver can be induced with 3'-methyl-4-dimethylaminoazobenzene (3'-MeDAB). In the present study, we investigated serum levels of alpha-fetoprotein (AFP) and thymidine kinase (TK), DNA-synthesizing enzyme in the salvage pathway, and tissue TK and its isozyme activities in the liver of rats treated with 3'-MeDAB. Serum TK activities rose abruptly right after the onset of 3'-MeDAB treatment, peaking after one week and then gradually decreasing. At 3 weeks, though serum TK was decreasing, serum AFP and tissue TK began to increase, and oval cells appeared in the liver. At 5 weeks, though serum TK reached a nadir, serum AFP and tissue TK formed transient peaks, and oval cells occupied a major part of the hepatic lobules with hyperplastic nodules. Thereafter, serum TK continued to increase, and serum AFP and tissue TK, after transiently decreasing, re-increased; at 20 weeks, each value was at high level, and mixed type hepatocarcinoma was observed. The liver TK isozymes were separated into 3 types by DEAE-cellulose column chromatography. A 3'-MeDAB induced a remarkable increase in activity of cytosolic and fetal type isozyme in non-tumorous regions of livers at 5 weeks and tumorous regions at 20 weeks. These results indicate that biochemical changes in 3'-MeDAB-treated rat liver may provide a valuable insight into two step process in hepatocarcinogenesis.

It has been known that a high incidence of adenocarcinoma in distal colon can be induced by s.c. injection of 1, 2-dimethylhydrazine (DMH) into rats at weekly intervals. We investigated effects of radiofrequency hyperthermia (RF-HT) in combination with anti-cancer drug UFT (a combination of tegafur and uracil) on activities of DNA-synthesizing enzymes, using colon carcinomas induced by DMH treatment in rats. 1) Thymidylate synthetase (TS), DNA-synthesizing enzyme in de novo pathway of pyrimidine metabolism, increased to approximately 7-fold that of normal control colon in DMH-induced colon carcinomas in activity, but was markedly reduced to 48% of that in the carcinomas by administration of UFT. 2) Thymidine kinase (TK) in salvage pathway increased to approximately 8-fold that of the control in the carcinomas in activity, but was markedly reduced to 25% of that in the carcinomas by RF-HT treatment. 3) The TK-isozyme, that was thought to be a fetal type in the intracellularly cytoplasmic fraction and closely involved in rapid DNA replication, increased to approximately 24-fold that of the control in the carcinomas in activity, but was reduced to the nearly same level as that of the control by RF-HT treatment. This isozyme was labile in thermostability and easy to be inactivated in low pH. 4) The activities of TS and TK in the carcinomas were extremely suppressed by UFT administration in combination with RF-HT treatment. These results indicate that hyperthermochemotherapy with UFT may serve as an available treatment for colon carcinomas.

Carcinoma of the colon was induced in rats by injection of a carcinogen 1,2-dimethylhydrazine (DMH), and thymidylate synthetase (TS) and thymidine kinase (TK) activities, which catalyze the biosynthesis of dTMP by the de novo pathway and the salvage pathway of pyrimidine synthesis, respectively, were measured in normal control colon, DMH-treated normal colon, and DMH-induced colon carcinoma with or without administration of two doses of an anti-cancer drug UFT (a combination of tegafur and uracil). TS and TK activities were both increased after treatment with DMH, markedly in colon carcinoma tissue, and to a lesser degree in normal-appearing colon tissue. This phenomenon is well explained by the hypothesis that biochemical alterations of DNA-synthesizing enzyme activities occur as a preliminary step prior to the development of overt cancerous transformation. A low dose of UFT inhibited TS activity but enhanced TK activity, therefore, the salvage pathway may compensate for the reduced level of the de novo synthesis. On the other hand, a large dose of UFT reduced both TS and TK activities, perhaps due to cytotoxic effects of UFT incorporation into RNA.

Thymidylate synthetase (TS) and thymidine kinase (TK) are known to catalyse the methylation of dUMP for the de novo synthesis of dTMP and the phosphorylation of thymidine for the salvage synthesis of dTMP in the pyrimidine pathway, respectively. High TS and TK activities have been observed in rapidly proliferating tissues such as foetal tissue, regenerating liver and carcinomas. TS and TK activities were measured in histologically normal colon mucosa and colorectal carcinomas with or without neo-adjuvant chemotherapy of an antitumor drug UFT (a combination of tegafur and uracil) in humans. In colorectal carcinomas, 5-FU and uracil levels were increased to 2.6- and 3.2-fold, respectively, those in normal colon mucosa by neo-adjuvant chemotherapy of UFT. In colorectal carcinomas, TS and TK activities were both increased to approximately 2- and 3-fold, respectively, those in normal colon mucosa without UFT treatment. In normal colon mucosa and colorectal carcinomas with neo-adjuvant chemotherapy of UFT, TS activities were reduced to approximately 50% and 40%, respectively, those without UFT treatment. These results indicate that neo-adjuvant chemotherapy with UFT may prevent dissemination of cancer cells during operation, and local recurrence and distant metastasis after operation, inhibiting DNA synthesis via the de novo pathway of pyrimidine synthesis in carcinomas.

Recent studies have suggested the possibility that the lightest supersymmetric particle is a suitable dark matter candidate. In this theoretical framework, annihilations in high density environments like the center of dark matter halo es may produce an intense flux of gamma-rays. In this paper we discuss the possibility of detecting the signatures of neutralino annihilation in nearby galaxies with next generation ground-based detectors.