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K Graf

Publications and source records attributed to K Graf.

At least 19 recordsLinked to original sources
PubMed2000

Peroxisome proliferator-activated receptor and retinoid X receptor ligands inhibit monocyte chemotactic protein-1-directed migration of monocytes.

Monocyte chemotactic protein-1 (MCP-1)-directed transendothelial migration of monocytes plays a key role in the development of inflammatory diseases. Infiltration of tissues by monocytes requires degradation of extracellular matrices, a process that involves matrix metalloproteinases. We studied the effects of peroxisome proliferator-activated receptor (PPAR) gamma, alpha, and retinoid X receptor alpha (RXRalpha) ligands on MCP-1-directed migration and matrix metalloproteinase expression of a human acute monocytic leukemia cell line (THP-1). PPARgamma ligands attenuated MCP-1-induced migration, with 50% inhibition (IC(50)) at 2.8 microM for troglitazone and 4.8 microM for rosiglitazone. PPARalpha ligands WY-14643 (IC(50): 0.9 microM) and 5,8,11,14-eicosatetranoic acid (IC(50): 9.9 microM), and the potent RXRalpha ligand AGN 4204 (IC(50): 3.6 nM) also blocked monocyte migration. Troglitazone, rosiglitazone, or AGN 4204 inhibited phorbol 12-myristate 13-acetate (PMA)-induced matrix metalloproteinase-9 expression. PPARalpha activators WY-14643 and 5,8,11,14-eicosatetraynoic acid, however, had no inhibitory effect. AGN 4204 increased PMA-induced tissue inhibitor of matrix metalloproteinases-1 (TIMP-1) expression, whereas all PPAR ligands showed no effect. All PPAR and RXRalpha ligands blocked chemotaxis of THP-1 monocytes in the absence of a matrix barrier. This study demonstrates that activated PPARs and RXRalpha, block MCP-1-directed monocyte migration, mediated, at least in part, through their effects on matrix metalloproteinase-9 or TIMP-1 production, or chemotaxis.

5,8,11,14-Eicosatetraynoic Acid↗
PubMed2000

Effects of abciximab and tirofiban on vitronectin receptors in human endothelial and smooth muscle cells.

human umbilical venous endothelial cells. 7E3 binding correlated with alphavbeta3-expression in all cell types. Integrin-mediated cell functions were analysed with adhesion and spreading assays on vitronectin. In human umbilical venous endothelial cells, these functions were mediated by alphavbeta3 and in human iliac arterial smooth muscle cells by alphavbeta5. In human umbilical venous smooth muscle cells, both vitronectin receptors were involved. Abciximab potently inhibited alphavbeta3-mediated cell adhesion and spreading. With tirofiban, no significant inhibition of vascular cell functions was observed. The present data demonstrate that vitronectin-cell interactions in vascular cells are mediated via two distinct integrin-receptors, alphavbeta3 and alphavbeta5. Abciximab, which solely inhibits alphavbeta3-mediated cell functions, may be particularly effective in human endothelium and in beta3-integrin expressing vascular smooth muscle cells.

Abciximab↗
PubMed2000

Angiotensin II directly increases transforming growth factor beta1 and osteopontin and indirectly affects collagen mRNA expression in the human heart.

OBJECTIVES: Angiotensin II (Ang II) induces fibroblast proliferation and collagen synthesis in the myocardium, but its precise mechanisms of action in human hearts are still unknown. Therefore, we investigated whether Ang II directly affects the collagen mRNA content in the human myocardium and in isolated human cardiac fibroblasts or whether the growth factors TGFbeta-1 and osteopontin are involved in this process. METHODS AND RESULTS I: In a first set of experiments, the direct effect of Ang II on collagen I, TGFbeta-1 and osteopontin mRNA content in fresh samples of human atrial myocardium was determined by the use of a short stimulation period. After 4 h, Ang II-stimulated atrial samples gave a significantly higher expression of both TGFbeta-1 (183+/-21% of control, p<0.05) and osteopontin mRNA (275+/-58%, p<0.02) than the controls. In contrast, the expression of collagen I mRNA was unchanged (95+/-8%). Stimulation with TGFbeta-1 led to an increase in collagen I and III mRNA (127+/-10%, p<0.05; 140+/-15%, p<0.02). METHODS AND RESULTS II: In a second protocol, to assess the effects of longer stimulation periods, we determined the effects of Ang II and its potential mediator TGFbeta-1 on collagen I, III and fibronectin mRNA expression and on proliferation of cultured human cardiac fibroblasts. Ang II caused a dose-dependent stimulation of proliferation but did not affect collagen I, II or fibronectin mRNA content after 24 h. In contrast, TGFbeta-1 stimulation significantly increased collagen I and III mRNA expression (124+/-5% and 128+/-5%, p<0.002). CONCLUSIONS: In the human heart, Ang II does not directly increase collagen or fibronectin mRNA, but it does increase TGFbeta-1 and osteopontin mRNA expression. Since TGFbeta-1 induces collagen I and III mRNA in atrial samples and in isolated cardiac fibroblasts, it may represent a necessary mediator of the Ang II effects in the human heart.

Aged↗
PubMed2000

Troglitazone inhibits mitogenic signaling by insulin in vascular smooth muscle cells.

Troglitazone (TRO) is an oral insulin-sensitizer that has direct effects on the vasculature to inhibit cell growth and migration. In vascular smooth muscle cells (VSMCs), insulin transduces a mitogenic signal that is dependent on the ERK1/2 MAP kinases. We examined the effects of TRO on this pathway and found that it inhibits mitogenic signaling. In quiescent VSMCs, insulin (1 microM) induced a 3.2-fold increase in DNA synthesis. TRO (1-20 microM) inhibited insulin-stimulated DNA synthesis by 72.8% at the maximal concentration. TRO at I and 10 microM had no significant effect on insulin-stimulated ERK1/2 activity. At 20 microM, however, TRO modestly enhanced insulin-stimulated ERK1/2 activity by 1.5-fold. ERKs transduce a mitogenic signal by phosphorylating transcription factors such as Elk-1. which regulate critical growth-response genes. We used GAL-Elk-1 expression plasmids to detect ERK-dependent activation of Elk-1. TRO at 1-20 microM potently inhibited insulin-stimulated, ERK1/2-dependent Elk-1 transcription factor activity. Neither early steps in insulin signaling nor the phosphatidylinositol 3-kinase (PI3K) branch of this pathway were affected by TRO, because it had no effect on IRS-1 phosphorylation, PI3K/IRS-1 association, or Akt phosphorylation. Because TRO is a known ligand for the nuclear transcription factor peroxisome proliferator-activated receptor gamma (PPARgamma), we tested two other ligands for this receptor, rosiglitazone (RSG) and 15-deoxy-delta12,14 prostaglandin J2 (15d-PGJ2). Both also inhibited insulin-induced DNA synthesis. In summary, these data show that TRO inhibits mitogenic signaling by insulin at a point distal of ERK1/2 activation, potentially by a PPARgamma-mediated inhibition of ERK-dependent phosphorylation and activation of nuclear transcription factors that regulate cell growth.

Animals↗
PubMed2000

Angiotensin II and PDGF-BB stimulate beta(1)-integrin-mediated adhesion and spreading in human VSMCs.

beta(1)-Integrins play an important role for adhesion and spreading of human smooth muscle cells. In the present study we examined the influence of angiotensin II and platelet-derived growth factor (PDGF)-BB on beta(1)-integrin-dependent functions of human smooth muscle cells obtained from iliac arteries. Treatment of these cells with PDGF-BB (20 ng/mL) and Angiotensin II (1 micromol/L) did not change beta(1)-integrin expression up to 48 hours as analyzed by flow cytometry and reverse transcription polymerase chain reaction. beta(1)-integrins predominantly mediated adhesion of human smooth muscle cells to collagen I (79.7+/-4.4%, P<0.01) and fibronectin (66. 6+/-2.4%, P<0.01). Treatment of smooth muscle cells with Angiotensin II (1 micromol/L) and PDGF-BB (20 ng/mL) significantly increased the adhesion to collagen I by 56.5% and 44.3%, respectively, and to fibronectin by 49.6% and 36.4%, respectively (all P<0.05). Angiotensin II-induced effects were mediated by the AT(1) receptor. The PDGF-BB mediated increase of adhesion was inhibited in the presence of genestein, a tyrosine-kinase inhibitor and by protein kinase C downregulation with phorbol 12-myristate 13-acetate. Spreading of smooth muscle cells also was beta(1)-integrin dependent on collagen I and alpha(5)beta(1)-integrin dependent on fibronectin. Angiotensin II and PDGF-BB increased cell spreading on fibronectin up to 276% and 318%, respectively, and on collagen I up to 133% and 138% (all P<0.05). These increases were significantly inhibited by blocking antibodies against beta(1)-integrin, alpha(5)-integrin on fibronectin, the AT(1) receptor blocker irbesartan, and genestein. The present data demonstrate that angiotensin II and as well PDGF-BB enhance beta(1)-integrin-dependent adhesion and spreading of human vascular smooth muscle cells. Furthermore, the experiments with PDGF suggest an involvement of protein kinase C activation leading to these enhanced effects.

Angiotensin II↗
PubMed2000

Angiotensin II enhances integrin and alpha-actinin expression in adult rat cardiac fibroblasts.

Angiotensin II (Ang II) plays an important role in cardiac remodeling through stimulation of proliferation and extracellular matrix (ECM) production in cardiac fibroblasts. Integrins are a family of transmembrane receptors that mediate the attachment of cells to ECM. We hypothesized that Ang II regulation of integrins further contributes to its role in cardiac remodeling. We cultured adult rat cardiac fibroblasts with and without Ang II (100 nmol/L) to determine the effects on mRNA and protein levels of integrins, as well as alpha-actinin and other cytoskeletal proteins that link to integrins at the site of focal adhesions. Ang II was also added in the presence of irbesartan (10 micromol/L), a specific Ang II type 1 (AT(1)) receptor antagonist, or PD 123319 (10 micromol/L), a specific Ang II type 2 receptor antagonist. To investigate the function of these integrins, we determined the effects of blocking antibodies on Ang II-induced adhesion to ECM. We also treated spontaneously hypertensive rats (SHR) with an AT(1) receptor blocker, losartan, or with hydralazine to investigate integrin and alpha-actinin expression in treated and untreated SHR. Ang II enhanced alpha(v), beta(1), beta(3), and beta(5) integrins; osteopontin; and alpha-actinin mRNA and protein levels in cardiac fibroblasts. All of these effects were inhibited by irbesartan but not by PD 123319. Pretreatment of cardiac fibroblasts with Ang II enhanced cell attachment to ECM proteins and induced focal adhesion kinase phosphorylation. Blocking antibodies to beta(3) and alpha(v)beta(5) attenuated Ang II-induced adhesion. In SHR, ventricular alpha(v) and beta(5) integrin expression and alpha-actinin were increased compared with those in Wistar-Kyoto rats. Although both losartan and hydralazine lowered mean arterial pressure and decreased peripheral vascular resistance, only losartan attenuated the increased integrin, alpha-actinin, fibronectin laminin, and osteopontin expression and the increased left ventricular mass (as determined with echocardiography). Hydralzine had none of these effects. Although both agents attenuated beta-myosin heavy chain expression, a marker of hypertrophy, losartan had a greater effect. These results suggest that integrins and alpha-actinin are upregulated by Ang II and in left ventricular hypertrophy and that the block of expression of these proteins through inhibition of the AT(1) receptor is associated with attenuation of the hypertrophic response. Ang II induces integrin and alpha-actinin expression in cardiac fibroblasts that is associated with adhesion and left ventricular hypertrophy and blocked through inhibition of the AT(1) receptor.

Actinin↗
PubMed2000

Angiotensin II and alpha(v)beta(3) integrin expression in rat neonatal cardiac fibroblasts.

We recently demonstrated that alpha(v)beta(3) integrins are involved in the mechanisms of angiotensin II (Ang II)-induced DNA synthesis and collagen gel contractions in rat cardiac fibroblasts (CFBs), cellular mechanisms that are relevant for cardiac remodeling. The aim of the present study was to elucidate the effect of Ang II and other growth factors on the regulation of the alpha(v)beta(3) integrins in fibroblasts from neonatal rat hearts. The alpha(v)beta(3) integrin receptor expression was significantly increased (P<0.05) at the mRNA level after treatment with Ang II, transforming growth factor-beta(1) (TGF-beta(1)), and platelet-derived growth factor (PDGF) for 8 and 16 hours. The surface expression of the alpha(v) and beta(3) integrin subunits was elevated after 32 and 48 hours (P<0.05) as determined with flow cytometry. To investigate fibroblast motility, we performed chemotaxis experiments with transwell chambers. Ang II was chemotactic for CFBs, as tested with checkerboard experiments. The chemotactic effect was concentration dependent and was completely blocked by Ang II type 1 receptor blockers but not by Ang II type 2 receptor blocker PD 123319. Ang II- and PDGF-BB-mediated chemotaxis could be significantly inhibited by RGD peptides and the blocking antibodies against alpha(v)beta(3) integrin (both P<0.01). Adhesion of CFBs to vitronectin was partially inhibited by an antibody to alpha(v)beta(3) integrin but was mainly mediated by an alpha(v)beta(5) integrin. Relevant in vivo expression of alpha(v)beta(3) integrin by CFBs was confirmed with in situ hybridization with probes for alpha(v) and beta(3) mRNA in rat hearts. The present study demonstrates that the expression of alpha(v)beta(3) integrin is augmented by Ang II, PDGF, and TGF-beta(1) in neonatal CFBs. Furthermore, this integrin is involved in the chemotaxis, motility, and adhesion of CFBs. The present findings support the current concept that integrins participate in the control of fibroblast behavior during cardiac remodeling mechanisms.

Angiotensin II↗
PubMed1999

Troglitazone inhibits angiotensin II-induced extracellular signal-regulated kinase 1/2 nuclear translocation and activation in vascular smooth muscle cells.

The thiazolidinedione troglitazone inhibits angiotensin II-induced extracellular signal-regulated kinase 1/2 mitogen-activated protein kinase activity in vascular smooth muscle cells. Activation of extracellular signal-regulated kinase 1/2 by angiotensin II is a multistep process involving both its phosphorylation by mitogen-activated protein kinase extracellular signal-regulated kinase kinase in the cytoplasm and a subsequent translocation to the nucleus. The cytoplasmic activation of extracellular signal-regulated kinase 1/2 in vascular smooth muscle cells proceeds through the protein kinase Czeta --> mitogen-activated protein kinase extracellular signal-regulated kinase kinase --> extracellular signal-regulated kinase pathway. Troglitazone did not affect the angiotensin II-induced activation of protein kinase Czeta or its downstream signaling kinases extracellular signal-regulated kinase 1/2 in the cytosol. In contrast, angiotensin II-induced activation of protein kinase Czeta and extracellular signal-regulated kinase 1/2 in the nucleus were both inhibited by troglitazone. Nuclear translocation of extracellular signal-regulated kinase 1/2 induced by angiotensin II was completely blocked by troglitazone. Protein kinase Czeta, however, did not translocate upon angiotensin II stimulation. Troglitazone, therefore, inhibits both angiotensin II-induced nuclear translocation of extracellular signal-regulated kinase 1/2 and the nuclear activity of its upstream signaling kinase protein kinase Czeta. Since extracellular signal-regulated kinase 1/2 nuclear translocation may be a critical signaling step for multiple growth factors that stimulate vascular smooth muscle cells proliferation and migration, troglitazone may provide a new therapeutical approach for the prevention and treatment of atherosclerosis and restenosis.

Angiotensin II↗
PubMed1999

[Differential reaction of human cardiac macro- and microvascular endothelial cells with respect to leucocyte adhesion and exposition to atherogenic lipoproteins].

While the cellular mechanisms of atherosclerosis have been intensively studied, the mechanisms leading to preferential localization of atherosclerotic lesions are less well understood. To further define these mechanisms, endothelial cells from coronary arteries, i.e., vessels with frequent atherosclerotic lesions, were isolated and grown in vitro. In order to compare the reactions of both cell types, endothelial cells derived from microvessels of human hearts were isolated and cultured under identical conditions. Incubation of endothelial cells with oxidized LDL (75 microg/ml protein) induced a significant increase in PAI-1 activity (182%, p < 0.05) in coronary macrovascular endothelial cells. This stimulatory effect of ox-LDL was less significant in microvascular endothelial cells (144%, p < 0.05). n-LDL did not influence secreted PAI-1 activity. Stimulation with angiotensin II induced expression of E-selectin more effectively in coronary macrovascular than in microvascular endothelial cells. In addition, angiotensin II-induced E-selectin expression led to increased E-selectin-dependent adhesion of HL60 cells to coronary macrovascular endothelial cells under flow conditions, while only little effect was observed with cardiac microvascular endothelial cells. In contrast, L-selectin-dependent adhesion, which has been shown to play an important role in inflammatory reactions, was preferentially observed in cardiac microvascular endothelial cells and could only be stimulated with TNFalpha, not by angiotensin II. Therefore, these cellular differences may in part explain specific properties of cardiac endothelial cells: Such that atherosclerotic lesions are localized in macrovascular vessel segments, whereas inflammatory responses are predominantly found in the microvasculature.

Cell Adhesion Molecules↗
PubMed1999

Functional, biochemical, and molecular investigations of renal kallikrein-kinin system in diabetic rats.

A reduction of renal kallikrein has been found in non-insulin-treated diabetic individuals, suggesting that an impaired renal kallikrein-kinin system (KKS) contributes to the development of diabetic nephropathy. We analyzed relevant components of the renal KKS in non-insulin-treated streptozotocin (STZ)-induced diabetic rats. Twelve weeks after a single injection of STZ, rats were normotensive and displayed hyperglycemia, polyuria, proteinuria, and reduced glomerular filtration rate. Blood bradykinin (BK) levels and prekallikrein activity were significantly increased compared with controls. Renal kallikrein activity was reduced by 70%, whereas urinary BK levels were increased up to threefold. Renal kininases were decreased as indicated by a 3-fold reduction in renal angiotensin-converting enzyme activity and a 1.8-fold reduction in renal expression of neutral endopeptidase 24.11. Renal cortical expression of kininogen and B2 receptors was enhanced to 1.4 and 1. 8-fold, respectively. Our data suggest that increased urinary BK levels found in severely hyperglycemic STZ-diabetic rats are related to increased filtration of components of the plasma KKS and/or renal kininogen synthesis in combination with decreased renal kinin-degrading activity. Thus, despite reduced renal kallikrein synthesis, renal KKS is activated in the advanced stage of diabetic nephropathy.

Animals↗
PubMed1999

Central role of the MAPK pathway in ang II-mediated DNA synthesis and migration in rat vascular smooth muscle cells.

Angiotensin II (Ang II) promotes vascular smooth muscle cell (VSMC) growth and migration, but the signaling pathways mediating these VSMC behaviors critical to restenosis and atherosclerosis are not completely known. The purpose of the present investigation was to define the role of mitogen-activated protein kinase (MAPK) in Ang II-induced DNA synthesis, migration, and c-fos induction in VSMCs. PD 98059, a synthetic inhibitor of MAPK kinase, or antisense oligodeoxynucleotides (ODNs) to deplete extracellular signal-regulated kinase (ERK)1 and ERK2 MAPKs, were used to inhibit MAPK signaling. PD 98059 at 30 micromol/L reduced Ang II-induced MAPK activity by 69% (P<0.01). Under these conditions, Ang II-induced DNA synthesis was completely inhibited (P<0.01), and Ang II-directed migration was attenuated by 76% (P<0.05). In contrast, induction of c-fos by Ang II was only partially suppressed (58% inhibition, P<0.01). Antisense ODNs against the initiation site of rat ERK1 and ERK2 MAPK mRNAs reduced corresponding protein levels by 63% (P<0.01) and completely inhibited MAPK activation by either Ang II (1 micromol/L) or 10% serum. Antisense ODNs (0.4 micromol/L) completely inhibited Ang II-induced DNA synthesis (P<0.01), decreased migration by 47% (P<0.01), and reduced c-fos induction by 40% (P<0.01 versus control ODN-transfected VSMCs). The Ang II type 1 (AT1)-receptor blocker irbesartan completely blocked DNA synthesis, migration, MAPK activation, and c-fos induction by Ang II in VSMCs. These results demonstrate that activation of MAPK plays a crucial role in Ang II-directed migration and DNA synthesis through the AT1 receptor. In contrast, Ang II-mediated c-fos induction and migration were only partially inhibited by either antisense ODNs or PD 98059, suggesting that other pathways in addition to the MAPK pathway may be involved in these actions of Ang II. We conclude that MAPK is a critical regulatory factor for Ang II-mediated migration and growth in VSMCs. Ang II-induced DNA synthesis showed a stronger MAPK dependence than did Ang II-directed migration or c-fos induction.

Angiotensin II↗
PubMed1999

Angiotensin II promotes integrin-mediated collagen gel contraction by adult rat cardiac fibroblasts.

Remodeling is a fundamental cardiac response to injury and involves cardiac fibroblast proliferation and extracellular matrix (ECM) production. Angiotensin II (Ang II) directly promotes these changes in cardiac fibroblasts and thus, plays critical roles in cardiac hypertrophy and wound healing. Osteopontin, fibronectin and laminin mRNA were detected in total RNA harvested from cultured adult rat cardiac fibroblasts. Immunocytochemistry staining of cultured adult rat cardiac fibroblasts grown on coverslips revealed the presence of beta 3 integrins on the surfaces of the cells. In the present study, we investigated the role of Ang II in a model of wound repair using floating collagen gels harboring adult rat cardiac fibroblasts, and we determined which members of the integrin family existed on these cells. The presence of either MPIIIB10, a monoclonal antibody against osteopontin (7.2 micrograms/ml) or RGD (arginine-glycine-aspartate) peptide (10(4) M) had no effect on gel contraction. Osteopontin itself induced gel contraction; however this effect was completely neutralized by MPIIIB10 (7.2 micrograms/ml, RGD peptide (10(4) M) and a monoclonal antibody against rat beta 3 integrin (25 micrograms/ml). We identified alpha v, beta 3 and beta 5 integrins on adult rat cardiac fibroblasts by fluorescence-activated cell sorting and confirmed that RGD peptide and an antibody against beta 3 integrin completely blocked osteopontin-induced gel contraction. These results suggest that Ang II promotes cardiac wound healing and remodeling processes by inducing expression of osteopontin and beta 3 integrin by cardiac fibroblasts.

Angiotensin II↗
PubMed1998

Mitogen-activated protein kinase activation mediates PDGF-directed migration of RPE cells.

Growth factor-directed migration is a critical component of the wound healing response although little is known about the signaling pathways involved. We examined the effect of inhibiting the mitogen-activated protein kinase (MAPK) pathway on platelet-derived growth factor (PDGF) and fibronectin-induced cell migration of human retinal pigment epithelial (RPE) cells. Using transwell cell-culture chambers, the effect of PDGF-BB (10-50 ng/ml) and fibronectin on components of migration was measured with or without the MAPK pathway inhibitor PD98059 (10-30 microM) MAPK activation of serum-starved cells by PDGF-BB was demonstrated by an immunoprecipitation/kinase assay and by immunohistochemistry using antibody specific for phosphorylated MAPK. PDGF-BB (10 ng/ml) stimulated MAPK activity in RPE (10 min) and its nuclear localization (1 h). PD98059 inhibited the activation of MAPK by PDGF-BB or serum. PDGF-BB stimulated RPE chemokinesis, chemotaxis, and haptotaxis; chemokinesis was additively increased and chemotaxis synergistically increased by the presence of a fibronectin substratum. PD98059 potently inhibited fibronectin-induced haptotaxis and PDGF-BB-induced chemotaxis but inhibited chemokinesis only at higher PDGF-BB (50 ng/ml) concentrations in the presence of fibronectin substratum. These results demonstrate that MAPK is critically involved in multiple components of RPE migration in vitro and suggest the potential of targeting MAPK to inhibit RPE migration in vivo.

Becaplermin↗
PubMed1998

Glucocorticoids and protein kinase C regulate neutral endopeptidase 24.11 in human vascular smooth muscle cells.

Neutral endopeptidase 24.11 (NEP) degrades vasoactive peptides, including natriuretic peptides, kinins, angiotensins, and endothelins. It contributes to the regulation of vascular tone and body fluid homeostasis. In the present study the expression of NEP was investigated in cultured human smooth muscle cells derived from umbilical veins (HSMC) and human coronary arteries (HCSMC). A constitutive NEP expression was found in growing and starved smooth muscle cells and was about 4 fold higher than in endothelial cells derived from umbilical veins. Treatment of smooth muscle cells with dexamethasone (0.01-0.1 microM Dex) and with the protein kinase C activator, phorbol myristate acetate (0.1 microM PMA), increased NEP mRNA by 3-4 fold and two fold, respectively. Dexamethasone (0.1 microM) and prednisolone (0.1 microM) increased protein concentrations of NEP and NEP-activity after 3 days and continued to increase at 5 days, whereas PMA induced maximal increase of NEP concentrations after 48 hours. The effect of dexamethasone was concentration-dependent and was completely abolished by cycloheximide (10 microM), a protein synthesis inhibitor. The effect of PMA on NEP protein was completely blocked by protein kinase C inhibitors, calphostin C and H7 (both 10 microM). NEP 24.11 is constitutively expressed in human smooth muscle cells from umbilical veins and coronary arteries and is upregulated by glucocorticoids and by protein kinase C activation in these cells.

Blotting, Northern↗
PubMed1998

Metacarpal index in short stature before and during growth hormone treatment.

AIMS: To assess the usefulness of the metacarpal index (MCI) as a radiographic measure of the proportions of the metacarpals in the differential diagnosis of short stature. To investigate the significance of the MCI in following the longitudinal growth and proportions of individual long bones during growth hormone stimulated catch up growth in children with short stature with and without growth hormone deficiency. SUBJECTS: 124 children, including 65 children with short stature caused by growth hormone deficiency, 13 with familial short stature, 29 with idiopathic short stature, and 17 with Ullrich-Turner syndrome. METHODS: Retrospective analysis of the MCI in five posterior-anterior radiographs of the left hand of all patients, which were performed sequentially for routine bone age determinations (Greulich and Pyle) before and during the first three years of growth hormone treatment. RESULTS: The MCI was similar in all patient groups, resembled that of healthy children, and correlated significantly with chronological age, bone age, and height before and during growth hormone treatment. Despite a remarkable growth hormone stimulated catch up growth, the MCI did not change significantly during growth hormone treatment. CONCLUSIONS: The role of the MCI is insignificant in the diagnosis of short stature, but the MCI can serve as an auxological measure of osseous proportions during longitudinal growth. Growth hormone treatment accelerates longitudinal growth without affecting the proportions of the long bones, indicating that growth hormone stimulated bone growth closely resembles spontaneous bone growth.

Body Height↗