Andreas P. Russ

Contribution of angiotensin i converting enzyme gene polymorphism and angiotensinogen gene polymorphism to blood pressure regulation in essential hypertension

The renin-angiotensin system (RAS) is involved in the pathogenesis of essential hypertension. In the present study we examined the genotype frequencies of the insertion/deletion polymorphisms of the ACE gene and the M235T polymorphism of the Angiotensinogen (Agt) gene in patients with essential hypertension in comparison with normotensive subjects. In hypertensive patients functional effects of blood pressure response to ACE inhibition were investigated. A total of 121 patients with essential hypertension (group 1) and 125 normotensive control subjects (group 2) were included in this study. All patients were genotyped by polymerase chain reactions (PCR) for the insertion/deletion (I/D) polymorphism of the ACE gene and the M235T polymorphism of the Agt gene. To analyze possible functional impacts on blood pressure regulation 50 mg of captopril was administered to hypertensive patients. No significant association of essential hypertension with polymorphisms of the Agt and ACE gene was found. The ACE serum levels in patients with the DD-genotype of the ACE I/D polymorphism were higher than in patients with the II-genotype (P < .01). In patients with the ID-genotype the ACE serum levels were in-between. A captopril test was performed in hypertensive patients. The patients were further divided into subgroups according to the diastolic and systolic blood pressure response. Group 1a consisted of patients with a diastolic blood pressure drop of > 5 mm Hg and group 1b with < or =5 mm Hg. Group 1c consisted of patients with a systolic blood pressure drop of > 10 mm Hg and group 1d with < or =10 mm Hg. Twice as many patients with the DD genotype of the ACE gene were found in group 1a compared to group 1b (chi(2) = 5.673; P = .017). No association of systolic blood pressure change to the investigated polymorphisms was found. Our results do not support the hypothesis that the investigated polymorphisms contribute to essential hypertension. Furthermore, no major impact of these polymorphisms on blood pressure response to captopril were detected. We conclude that the investigated genotypes have no influence on blood pressure level and homeostasis.

Selective Disruption of Genes Transiently Induced in Differentiating Mouse Embryonic Stem Cells by Using Gene Trap Mutagenesis and Site-Specific Recombination

ABSTRACT A strategy employing gene trap mutagenesis and site-specific recombination (Cre/loxP) has been used to identify genes that are transiently expressed during early mouse development. Embryonic stem cells expressing a reporter plasmid that codes for neomycin phosphotransferase and Escherichia coli LacZ were infected with a retroviral gene trap vector (U3Cre) carrying coding sequences for Cre recombinase (Cre) in the U3 region. Activation of Cre expression from integrations into active genes resulted in a permanent switching between the two selectable marker genes and consequently the expression of β-galactosidase (β-Gal). As a result, clones in which U3Cre had disrupted genes that were only transiently expressed could be selected. Moreover, U3Cre-activating cells acquired a cell autonomous marker that could be traced to cells and tissues of the developing embryo. Thus, when two of the clones with inducible U3Cre integrations were passaged in the germ line, they generated spatial patterns of β-Gal expression.

Amplification and direct sequencing of a cDNA encoding human cytosolic 3-hydroxy-3-methylglutaryl-coenzyme A synthase

Cytosolic 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) synthase (E.C. 4.1.3.5) is a highly regulated enzyme involved in isoprenoid biosynthesis and therefore a potential target for cholesterol-lowering drugs. Up to now, primary structure data have only been available for chicken, rat and hamster HMG-CoA synthase. Using in vitro amplification and direct sequencing, we have determined the nucleotide sequence of the coding region of the human cytosolic 3-hydroxy-3-methylglutaryl CoA synthase cDNA.