Angiotensin-converting enzyme gene polymorphism in patients with minimal-change nephrotic syndrome and focal segmental glomerulosclerosis.

To evaluate angiotensin-converting enzyme (ACE) gene insertion/deletion polymorphism in nephrotic syndrome, 85 patients (minimal-change nephrotic syndrome, MCNS: 55 cases; focal segmental glomerulosclerosis, FSGS: 30 cases) and 61 control subjects were examined. The distribution of ACE genotype in the control group was II 44%, ID 41% and DD 15%. The distribution of ACE genotypes in MCNS was similar to that in controls.

Genetically selected cardiomyocytes from differentiating embronic stem cells form stable intracardiac grafts.

This study describes a simple approach to generate relatively pure cultures of cardiomyocytes from differentiating murine embryonic stem (ES) cells. A fusion gene consisting of the alpha-cardiac myosin heavy chain promoter and a cDNA encoding aminoglycoside phosphotransferase was stably transfected into pluripotent ES cells. The resulting cell lines were differentiated in vitro and subjected to G418 selection.

Molecular determinants of the clearance function of type C receptors of natriuretic peptides.

Receptor-mediated endocytosis is the cellular mechanism by which type C receptors of natriuretic peptides exert their clearance function. In the present work, performed in recombinant Chinese hamster ovary cells stably transfected with wild type or mutated human kidney C receptors, we determined net endocytic rates (ER) of C receptor-ligand complexes, lysosomal hydrolysis of ligand (125I-labeled native atrial natriuretic factor, ANF1-28), and receptor recycling. Equilibrium ligand binding, immunocytochemistry, and immunoprecipitation were performed to characterize the transfected receptors.

Changes of atrial natriuretic peptide level in patients with nephrotic syndrome after supine bicycle exercise.

Objectives: The exact role of atrial natriutetic peptide (ANP) in the pathogenesis of edema in nephrotic syndrome (NS) has not been fully elucidated. We aimed to investigate the possible contribution of ANP to edema formation in NS.

Methods: We subjected 18 nephrotic subjects and 20 healthy volunteers to supine bicycle exercise (SBE), a maneuver that seemed to increase venous return and to enhance the release of ANP.

Stable fetal cardiomyocyte grafts in the hearts of dystrophic mice and dogs.

This report documents the formation of stable fetal cardiomyocyte grafts in the myocardium of dystrophic dogs. Preliminary experiments established that the dystrophin gene product could be used to follow the fate of engrafted cardiomyocytes in dystrophic mdx mice. Importantly, ultrastructural analyses revealed the presence of intercalated discs consisting of fascia adherens, desmosomes, and gap junctions at the donor-host cardiomyocyte border.

Strategies for myocardial repair.

The therapeutic recourse for end-stage heart disease is currently limited to cardiac transplantation. The ability to augment cardiomyocyte number in an end-stage heart might facilitate myocardial function. Augmentation of cardiomyocyte number may be achievable by the targeted expression of cell cycle regulatory genes to the myocardium.

Potential approaches for myocardial regeneration.

Cardiomyocytes in the adult mammal retain little or none of their developmental capacity for hyperplastic growth. As a consequence of this differentiated, nonproliferative phenotype, cardiomyocyte loss due to injury or disease is irreversible. Therapeutic intervention in end-stage diseased hearts is currently limited to cardiac transplantation.

Targeted expression of transforming growth factor-beta 1 in intracardiac grafts promotes vascular endothelial cell DNA synthesis.

Intracardiac grafts comprised of genetically modified skeletal myoblasts were assessed for their ability to effect long-term delivery of recombinant transforming growth factor-beta (TGF-beta) to the heart. C2C12 myoblasts were stably transfected with a construct comprised of an inducible metallothionein promoter fused to a modified TGF-beta 1 cDNA. When cultured in medium supplemented with zinc sulfate, cells carrying this transgene constitutively secrete active TGF-beta 1.

Delayed processing of the insulin proreceptor by hepatocytes from diabetic rats.

The effect of diabetes on insulin receptor processing was assessed in rat hepatocytes, 2-4 weeks after the induction of diabetes with streptozotocin. Isolated hepatocytes from control and diabetic rats were labelled for 30 min with [35S]methionine in methionine-free medium and chased with complete medium for 1-3 hrs. Solubilized cell extracts were immunoprecipitated with a site-specific anti-insulin receptor antibody, proteins were separated by electrophoresis and labelling quantified following autoradiography.

Tumor suppressor gene expression during normal and pathologic myocardial growth.

Previous studies have identified several host proteins (p53, p107, and p193), which form prominent complexes with SV40 T antigen in transformed cardiomyocytes. Expression of p53 and p107 was monitored during normal and pathologic growth in nontransformed murine myocardium. Both genes were expressed at relatively high levels in embryonic cardiomyocytes.

Formation of nascent intercalated disks between grafted fetal cardiomyocytes and host myocardium.

Fetal cardiomyocytes isolated from transgenic mice carrying a fusion gene of the alpha-cardiac myosin heavy chain promoter with a beta-galactosidase reporter were examined for their ability to form stable intracardiac grafts. Embryonic day 15 transgenic cardiomyocytes delivered directly into the myocardium of syngeneic hosts formed stable grafts, as identified by nuclear beta-galactosidase activity. Grafted cardiomyocytes were observed as long as 2 months after implantation, the latest date assayed.

Atrial natriuretic factor and transgenic mice.

Atrial natriuretic factor (ANF) is a peptide hormone that induces potent but transient hypotensive and natriuretic responses on short-term administration. The role of the hormone in long-term cardiovascular regulation has remained elusive in part because of the temporal limitations of long-term infusion models and the extremely short half-life of the molecule in vivo. To circumvent these temporal limitations, a transgenic mouse model was developed that exhibits lifelong elevated plasma ANF levels.

Differentiation and long-term survival of C2C12 myoblast grafts in heart.

We have assessed the ability of skeletal myoblasts to form long-term, differentiated grafts in ventricular myocardium. C2C12 myoblasts were grafted directly into the heart of syngeneic mice. Viable grafts were observed as long as 3 mo after implantation.

Long-term survival of AT-1 cardiomyocyte grafts in syngeneic myocardium.

The long-term viability of cardiomyocyte grafts in the adult myocardium was tested. AT-1 cardiomyocytes, a differentiated tumor line derived from transgenic mice expressing an atrial natriuretic factor-simian virus 40 T antigen fusion gene, were grafted directly into the myocardium of syngeneic animals. Viable grafts were detected as long as 4 mo postimplantation.

Single injection of pentobarbital induces long-lasting effects on ANP synthesis and gene expression in the rat atria.

To define the long-term effects of pentobarbital sodium on the plasma and atrial atrial natriuretic peptide (ANP) system, experiments were performed in female Sprague-Dawley rats. The plasma levels of immunoreactive (ir) ANP showed chronic as well as acute response to pentobarbital sodium administration. A single dose (30 mg/kg, i.

Circulating levels and bone contents of bone gamma-carboxyglutamic acid-containing protein in rat models of non-insulin-dependent diabetes mellitus.

In order to investigate the pathophysiology of the diabetic osteopenia observed in non-insulin-dependent diabetes mellitus, the circulating levels and the bone contents of bone gamma-carboxyglutamic acid-containing protein (osteocalcin) were determined in rat models of non-insulin-dependent diabetes mellitus, neonatally streptozotocin-induced rats and in genetic Wistar fatty rats. In Wistar fatty rats the plasma level of osteocalcin was 8.1 +/- 0.

Deletion analysis of DMD/BMD children in Singapore using multiplex polymerase chain reaction (PCR) technique.

Twenty-three children suffering from Duchenne/Becker muscular dystrophy (DMD/BMD) in Singapore were analysed using the multiplex polymerase chain reaction (PCR) technique. Deletions were found in 14 cases. One rare case of total deletion of all nine exons was observed.

Clearance receptor and neutral endopeptidase-mediated metabolism of atrial natriuretic factor.

A novel small linear C-atrial natriuretic factor receptor ligand [C-ANF-(11-15)] and phosphoramidon (PHO) were used to determine the effects of C-ANF receptor blockade alone, or in combination with inhibition of neutral endopeptidase (NEP), on the pharmacokinetics and metabolism of ANF in the rat. C-ANF-(11-15) infusion decreased apparent volume of distribution (Vss) and metabolic clearance rate (MCR) of administered 125I-ANF-(1-28) to one-third of their control values, whereas PHO alone was without effect on these parameters. In combination with C-ANF-(11-15), however, PHO further decreased MCR of 125I-ANF-(1-28) and increased plasma half time by more than threefold.

Dynamics of atrial natriuretic factor-guanylate cyclase receptors and receptor-ligand complexes in cultured glomerular mesangial and renomedullary interstitial cells.

The dynamics of the guanylate cyclase receptor of atrial natriuretic factor (GCA-ANF receptor) were investigated in cultured glomerular mesangial and renomedullary interstitial cells from the rat. In these cells, the GCA-ANF receptor did not mediate internalization and lysosomal hydrolysis of 125I-ANF1-28 and did not undergo ligand-induced endocytosis. Glomerular mesangial cells were able, however, to mediate internalization and lysosomal hydrolysis of 125I-ANF1-28 via clearance ANF (C-ANF) receptors and to promote rapid receptor-mediated internalization and lysosomal hydrolysis of 125I-(Sar1) angiotensin II.

Insulin and glucose transporter gene expression in obesity and diabetes.

In order to determine the role of insulin and glucose transporter gene expression in the development of diabetes in obesity, we examined insulin and GLUT2-liver type and GLUT4-muscle-fat type glucose transporter mRNA levels in obese and diabetic rats. Ventromedial hypothalamus-lesioned (VMH), Zucker fatty (ZF), and Wistar fatty (WF) rats were used as models. VMH and ZF rats are most frequently used as models for simple obesity.

Ovarian atrial natriuretic peptide during the rat estrous cycle.

The changes in ovarian levels of immunoreactive atrial natriuretic peptide (irANP) and arginine vasopressin (irAVP) were observed during the estrous cycle of rat. We also demonstrated the synthesis of ovarian ANP. In adult 4-day cycling rats, ovarian level of irANP was found to be the highest on proestrus and was to be the lowest on diestrus.

Liver and muscle-fat type glucose transporter gene expression in obese and diabetic rats.

In order to investigate the regulation of glucose transporter gene expression in the altered metabolic conditions of obesity and diabetes, we have measured mRNA levels encoding GLUT2 in the liver and GLUT4 in the gastrocnemius muscle from various insulin resistant animal models, including Zucker fatty, Wistar fatty, and streptozocin(STZ)-treated diabetic rats. Northern blot analysis revealed that GLUT2 mRNA levels were significantly (P less than 0.001) elevated in 14 wk Zucker fatty and Wistar fatty rats relative to lean littermates but were similar in these two groups at 5 wk of age.