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A higher concentration of H2O2 solution (>1 wt%) was catalytically and directly synthesized from O2 and H2 over a [active carbon+vapor-grown-carbon-fiber] cathode by a new type of fuel cell system at 1 atm.

A bovine genomic library was constructed using a cosmid vector, pHC79, and bovine DNA partially digested by EcoRI. Bovine P-450(11 beta) cDNA, pcP-450(11 beta)-2 [Morohashi et al. (1987) J. Biochem. 102,559-568], was used as a probe for screening the genomic library. Ten clones carrying P-450(11 beta) genomic DNA were isolated from 8 x 10(4) colonies and classified into five groups (CB11 beta-1, CB11 beta-3, CB11 beta-7, CB11 beta-20, and CB11 beta-21) according to differences in the restriction endonuclease sites. Nucleotide sequences of amino acid coding regions of the five clones were determined by the dideoxy sequencing method using synthetic nucleotides corresponding to various parts of the cDNA as primers. The nucleotide sequences revealed that three clones, CB11 beta-1, CB11 beta-3, and CB11 beta-21, were pseudogenes. Amino acid sequences coded by the other two clones, CB11 beta-7 and CB11 beta-20, were identical with that coded by a previously described cDNA, pcP-450(11 beta)-3 [Kirita et al. (1988) J. Biochem. 104, 683-686]. The promoter regions of the five clones were introduced in front of chloramphenicol acetyltransferase (CAT) gene of pSV00CAT and used to examine P-450(11 beta) gene regulation in cultured cells. The five recombinant plasmids showed cAMP-responsive CAT activities in Y-1 cells, a cell strain derived from adrenal tumor. The induction rates of the recombinant plasmids carrying the promoters of normal genes, CB11 beta-7 and -20, were larger than those of pseudogenes, CB11 beta-1, -3, and -21. CAT activities expressed by the promoter regions of the normal genes in the presence or absence of cAMP in Y-1 cells were almost equal to that by the promoter region of human P-450(SCC) gene. Though the promoter of the P-450(SCC) gene also showed cAMP-responsive CAT activity in I-10 cells, a cell strain derived from Leyding cell tumor, P-450(11 beta) gene promoter did not express the activity in I-10 cells.

Insulin resistance is linked with a cluster of multiple risk factors for atherosclerosis, such as diabetes, hypertension and dyslipidaemia. The underlying mechanism for a cluster of risk factors and subsequent acceleration of atherosclerosis, however, are not fully understood. Recently, non-esterified fatty acids (NEFAs) have emerged as an important link between obesity, insulin resistance, and Type II (non-insulindependent) diabetes mellitus [1]. Plasma non-esterified fatty acids (NEFAs), which are commonly higher in obesity, can induce peripheral and hepatic insulin Diabetologia (2001) Abstract Aims/hypothesis. Insulin resistance is linked with a cluster of multiple risk factors and excessive acceleration of atherosclerosis. The underlying mechanism is not, however, fully understood. Methods. To determine the link between insulin resistance and altered vascular function, we focused on the effect of various non-esterified fatty acids on diacylglycerol-protein kinase C pathway and mitogenactivated protein kinase activity in cultured aortic smooth muscle cells. Results.Incubation of the cells with saturated non-esterified fatty acids (200 mmol/l) for 24 h, such as palmitate or stearate, induced a significant increase in diacylglycerol concentrations by about fivefold or eightfold, respectively, whereas oleate induced a slight increase in diacylglycerol concentrations by 1.8-fold and arachidonate induced none. In addition, the increased diacylglycerol concentrations induced by palmitate were completely restored to control concentrations by triacsin C, acyl-CoA synthetase inhibitor. These results suggest that saturated non-esterified fatty acids may increase diacylglycerol concentrations through de novo pathway by stepwise acylation. In parallel with the increased diacylglycerol, incubation of the cells with saturated non-esterified fatty acids significantly induced the activation of protein kinase C and mitogen-activated protein kinase. The palmitate-induced increase in mitogen-activated protein kinase activity was restored to control concentrations by GF109203X (5´10 ±7 mol/l), a specific protein kinase C inhibitor, suggesting a protein kinase C-dependent activation of mitogen-activated protein kinase. Conclusion/interpretation. Saturated non-esterified fatty acids induced an increase in de novo diacylglycerol synthesis and subsequent activation of protein kinase C and mitogen-activated protein kinase in cultured aortic smooth muscle cells. This could contribute to the altered vascular functions in the insulin resistant state. [Diabetologia (2001) 44: 614±620]