Angiotensin I to angiotensin II conversion in the human forearm and leg. Effect of the angiotensin converting enzyme gene insertion/deletion polymorphism.

Objective: The angiotensin-converting enzyme (ACE) gene I/D polymorphism accounts for part of the variation in ACE concentration; subjects with one or two D alleles have approximately 25 and 50% higher ACE levels, respectively, than subjects with two I alleles. Data from studies on the pressor effects of angiotensin (Ang) I in DD compared with II subjects are inconsistent, because enhanced conversion in DD subjects may have been masked by a decreased responsiveness to Ang II. Here we quantify ACE genotype-related Ang I to Ang II conversion in the human forearm and leg using non-pressor 125I-Ang I infusions.

AT1 receptor A/C1166 polymorphism contributes to cardiac hypertrophy in subjects with hypertrophic cardiomyopathy.

The development of left ventricular hypertrophy (LVH) in subjects with hypertrophic cardiomyopathy (HCM) is variable, suggesting a role for modifying factors such as angiotensin II. We investigated whether the angiotensin II type 1 receptor (AT1-R) A/C1166 polymorphism, the angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphism, and/or plasma renin influence LVH in HCM. Left ventricular mass index (LVMI) and interventricular septal thickness were determined by 2-dimensional echocardiography in 104 genetically independent subjects with HCM.

Activation of overexpressed receptors for insulin and epidermal growth factor interferes in mitogenic signaling without affecting the activation of p21ras.

Activated receptors with a tyrosine kinase activity induce a variety of responses like changes in the differentiation and mitogenic status of cells. These responses are mediated in part by p21ras. Some of these activated receptors induce in certain cell types a pronounced, but transient, increase in Ras-GTP.

Epidermal-growth-factor receptors generate Ras.GTP more efficiently than insulin receptors.

Activation of the Ras proto-oncogene contributes in general to mitogenic activation of cells. We show here that epidermal growth factor (EGF) stimulates Ras.GTP formation very efficiently in a variety of cell lines expressing endogenous EGF receptors only.

Relation between the insulin receptor number in cells, autophosphorylation and insulin-stimulated Ras.GTP formation.

We showed previously that upon insulin stimulation of an insulin receptor overexpressing cell line, most of the p21ras was rapidly converted into the GTP bound state (Burgering, B. M. T.

The role of ras proteins in insulin signal transduction.

Ras-proteins are guanine nucleotide binding proteins, which, in the GTP bound state emit a strong mitogenic signal. In the GDP bound state, the protein appears inactive. We have found that stimulation by insulin of cells expressing elevated levels of insulin receptors results in a rapid conversion of Ras-GDP into Ras-GTP.

Identification and characterization of a novel antigen complex on mouse mammary tumor cells using a monoclonal antibody against platelet glycoprotein Ic.

The rat monoclonal antibody GoH3 identifies a complex of glycoproteins Ic and IIa on human and mouse platelets. The GoH3 epitope is located on glycoprotein Ic. A novel glycoprotein complex is identified by GoH3 on the surface membranes of mouse mammary epithelial tumor cells.

Analysis of doxorubicin, 4'-epidoxorubicin, and their metabolites by liquid chromatography.

An analytical method based on isocratic HPLC separation and fluorescence detection was developed to allow for sensitive and specific analysis of anthracyclines and their metabolites in plasma and urine. The method is particularly advantageous when comparing the metabolism and/or pharmacokinetics of analogues, such as doxorubicin [(8S, 10S)-10-[(3-amino-2,3,6-trideoxy-alpha-L-lyxo-hexopyranosyl)- oxy]-8-glycolyl-7,8,9,10-tetrahydro-6,8,11-trihydroxy-1-meth- oxy-5,12-naphthacenedione] (1) and 4'-epidoxorubicin (2), since both drugs and their metabolites can be analyzed under identical conditions. The analytical properties of 1, 2, and eight metabolites were studied in plasma, serum, buffer solution, and urine.