Sildenafil Protects Endothelial Cells From Radiation-Induced Oxidative Stress.

INTRODUCTION: The etiology of radiation-induced erectile dysfunction (ED) is complex and multifactorial, and it appears to be mainly atherogenic. AIM: To focus on vascular aspects of radiation-induced ED and to elucidate whether the protective effects of sildenafil are mediated by attenuation of oxidative stress and apoptosis in the endothelial cells. METHODS: Bovine aortic endothelial cells (BAECs), with or without pretreatment of sildenafil (5 µM at 5 minutes before radiation), were used to test endothelial dysfunction in response to external beam radiation at 10-15 Gy. Generation of reactive oxygen species (ROS) was studied. Extracellular hydrogen peroxide (H2O2) was measured using the Amplex Red assay and intracellular H2O2 using a fluorescent sensor. In addition, ROS superoxide (O2•-) was measured using a O2•- chemiluminescence enhancer. Both H2O2 and O2•- are known to reduce the bioavailability of nitric oxide, which is the most significant chemical mediator of penile erection. Generation of cellular peroxynitrite (ONOO-) was measured using a chemiluminescence assay with the PNCL probe. Subsequently, we measured the activation of acid sphingomyelinase (ASMase) enzyme by radioenzymatic assay using [14C-methylcholine] sphingomyelin as substrate, and the generation of the proapoptotic C16-ceramide was assessed using the diacylglycerol kinase assay. Endothelial cells apoptosis was measured as a readout of these cells' dysfunction. MAIN OUTCOME MEASURES: Single high-dose radiation therapy induced NADPH oxidases (NOXs) activation and ROS generation via the proapoptotic ASMase/ceramide pathway. The radio-protective effect of sildenafil on BAECs was due to inhibition of this pathway. RESULTS: Here, we demonstrate for the first time that radiation activated NOXs and induced generation of ROS in BAECs. In addition, we showed that sildenafil significantly reduced radiation-induced O2•- and as a result there was reduction in the generation of peroxynitrite in these cells. Subsequently, sildenafil protected the endothelial cells from radiation therapy-induced apoptosis. STRENGTHS AND LIMITATIONS: This is the first study demonstrating that single high-dose radiation therapy induced NOXs activation, resulting in the generation of O2•- and peroxynitrite in endothelial cells. Sildenafil reduced ROS generation by inhibiting the ASMase/ceramide pathway. These studies should be followed in an animal model of ED. CONCLUSIONS: This study demonstrated that sildenafil protects BAECs from radiation-induced oxidative stress by reducing NOX-induced ROS generation, thus resulting in decreased endothelial dysfunction. Therefore, it provides a potential mechanism to better understand the atherogenic etiology of postradiation ED. Wortel RC, Mizrachi A, Li H, et al. Sildenafil Protects Endothelial Cells From Radiation-Induced Oxidative Stress. J Sex Med 2019;16:1721-1733.

[Recent development of hypertension and acute renal failure in a 59-year-old woman]. / Neu aufgetretene Hypertonie und akutes Nierenversagen bei einer 59-jährigen Patientin.

We report on a 59-year-old woman who presented with nausea, fatigue, arterial hypertension, and acute renal failure. Clinical examination, laboratory findings of blood and urine and abdominal sonography were inconclusive. Renal biopsy revealed infiltration by a diffuse large B­cell lymphoma. In fluorodeoxyglucose positron emission tomography/computed tomography tracer enrichment was demonstrated in both kidneys, skeletal system and retroperitoneal lymph nodes. Renal function improved already after the first cycle of R­CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone). After chemotherapy, a complete remission, normalization of blood pressure and renal function were achieved.

Transvenous Renal Transplant Biopsy via a Transfemoral Approach.

Percutaneous renal biopsy (PRB) of kidney transplants might be prevented by an elevated risk of bleeding or limited access to the allograft. In the following, we describe our initial experience with 71 transvenous renal transplant biopsies in 53 consecutive patients with unexplained reduced graft function who were considered unsuitable candidates for PRB (4.2% of all renal transplant biopsies at our institution). Biopsies were performed via the ipsilateral femoral vein with a renal biopsy set designed for transjugular renal biopsy (TJRB) of native kidneys. Positioning of the biopsy system within the transplant vein was achievable in 58 of 71 (81.7%) procedures. The specimen contained a median of 10 glomeruli (range 0-38). Tissue was considered as adequate for diagnosis in 56 of 57 (98.2%) biopsies. With respect to BANFF 50.9% of the specimen were adequate (>10 glomeruli), 47.4% marginally adequate (1-9 glomeruli) and 1.8% inadequate (no glomeruli). After implementation of real-time assessment all specimen contained glomeruli. One of the fifty-eight (1.8%) procedure-related major complications occurred (hydronephrosis requiring nephrostomy due to gross hematuria). Transfemoral renal transplant biopsy (TFRTB) is feasible and appears to be safe compared to PRB. It offers a useful new alternative for histological evaluation of graft dysfunction in selected patients with contraindications to PRB.

First Report of Bacterial Gall on Loropetalum chinense Caused by Pseudomonas savastanoi in the United States.

Bacterial gall symptoms were observed on Loropetalum chinense (R. Br.) Oliv. in two separate commercial nurseries in South Alabama during the spring of 2012. Limb dieback and plant death was first reported by the growers. Plants with dieback symptoms had galling and irregular dark callus formation on the lower stem and lower branches. Galls were small, 0.2 to 1 cm, inconspicuous, and in some cases girdled the stem causing breakage of the main stem. In both locations, 30 to 40% of the crop was affected. Similar symptoms have been observed on L. chinense in nursery and landscape plantings in central Alabama, North Carolina, and Georgia in previous years. Bacterial colonies were isolated from four plants representing two different locations. Isolates were recovered from surface sterilized symptomatic tissue on nutrient agar and King's medium B (KMB). All isolates were gram-negative and fluoresced blue-green under UV light after 48 h of growth at 28°C on KMB. One representative isolate from each site was identified as Pseudomonas savastanoi based on their fatty acid profiles (similarity index of 0.776; MIS-TSBA, version 4.0, MIDI Inc., Newark, DE) and LOPAT tests (2). The identity was confirmed by sequencing a 900-bp portion of the 16S rDNA gene, which revealed 98% similarity to the P. savastanoi type strain in NCBI (Accession No. AB021402). In greenhouse pathogenicity tests, eight Loropetalum liners were inoculated with a bacterial suspension (107 CFU/ml) of each of the two isolates. Plants were inoculated by injecting the suspension into the lower stem after wounding by puncturing with needles or slicing sections of the bark. Controls were inoculated with water. All plants inoculated with the bacteria developed gall symptoms in 8 weeks under 90% relative humidity at 30°C. The bacteria were reisolated from five inoculated plants. DNA was extracted from each isolate, amplified using primer pair 27F/1492R targeting the 16S rDNA gene (1), and sequenced. Sequences (900 bp) from all isolates shared 98 to 99% similarity to P. savastanoi type strain in GenBank (Accession No. AB021402). Nucleotide sequence data reported are available in GenBank under accessions JX915832 to 37. To our knowledge, this is the first report of bacterial gall of L. chinense caused by P. savastanoi in the United States. Given the increasing prevalence of this disease in South Alabama, its confirmation is a significant step toward management recommendations for growers. References: (1) D. J. Lane. 16S/23S rRNA sequencing. Page 115-175 in: Nucleic Acid Techniques in Bacterial Systematics. E. Stackebrandt and M. Goodfellow, eds. John Wiley and Sons, New York, 1991. (2) N. W. Schaad et al. Laboratory Guide for Identification of Plant Pathogenic Bacteria. 3rd ed. The American Phytopathological Society, St. Paul, MN, 2001.

Sympathetic blockade prevents the decrease in cardiac VEGF expression and capillary supply in experimental renal failure.

Uremic cardiomyopathy of men and rodents is characterized by lower myocardial capillary supply that in rats could be prevented by central and peripheral blockade of the sympathetic nervous system. The underlying pathomechanisms remain largely unknown. We investigated whether alterations of cardiac vascular endothelial growth factor (VEGF) gene and protein expression were involved. In our long-term experiment, we analyzed whether VEGF gene and protein expression was altered in the heart of male Sprague-Dawley rats with either sham operation (sham, n=10) or subtotal nephrectomy (SNX, n=10). In our short-term experiment (17 sham, 24 SNX), the effect of a putative downregulation of sympathetic nervous activity by surgical renal denervation (interruption of renal afferent pathways) on cardiac gene expression of VEGF, flt-1, and flk-1 and on myocardial capillary supply was analyzed. In the long-term study, cardiac capillary supply and vascular endothelial growth factor gene and protein expression were significantly lower in SNX than in sham. In the short-term experiment, cardiac VEGF mRNA expression was significantly lower in untreated SNX (4,258±2,078 units) than in both sham groups (11,709±4,169 and 8,998±4,823 units); this decrease was significantly prevented by renal denervation (8,190±3,889, P<0.05). We conclude that cardiac VEGF gene and protein expression is reduced in experimental renal failure, and this may be considered as one potential reason for impaired myocardial adaptation under the situation of cardiac hypertrophy. The beneficial effect of sympathetic downregulation on cardiac structure and function in renal failure may be at least in part explained by increased cardiac VEGF gene expression.

Identification of Tomato yellow leaf curl virus and Tomato mottle virus in Two Counties in Alabama.

During July 2005, approximately 23% of tomato plants (Solanum lycopersicum L. 'Sebring') in a commercial field in St. Clair County, Alabama showed symptoms of stunting, leaf deformation, mottling, and reduced leaf size, which resembled symptoms of Tomato yellow leaf curl virus (TYLCV). A high population of whiteflies (Bemisia tabaci) was observed in this field, and as the season progressed, 100% of the plants became symptomatic. During October 2006, similar symptoms in tomato were observed at low incidences (less than 10%) in a commercial greenhouse in Jefferson County. Two samples from St. Clair County and six from Jefferson County were collected and tested for the presence of a begomovirus by PCR using three pairs of primers, PAR1c496 and PAL1v1978, a degenerate primer pair designed to amplify regions of the begomovirus A component, PBL1v2040 and PCRc154, a degenerate primer pair that amplifies a hypervariable region of the begomovirus B component (3), and C473 and PTYC1v2406, which are specific to TYLCV (1,2). Primer pair PAR1c496 and PAL1v1978 produced two amplicons (1,360 and 1,159 bp) in all samples tested, which suggests the presence of a monopartite and bipartite begomovirus. Primer pair pBL1v2040 and PCRc154 produced a 678-bp amplicon that would be consistent with the presence of a bipartite begomovirus. Primer pair C473 and PTYC1v2406 produced an 850-bp amplicon that would be consistent with the presence of TYLCV. Sequence analysis revealed that the 1,360-bp amplicon had 98% sequence identity to isolates of TYLCV from Cuba (GenBank Accession No. AJ223505), the Dominican Republic (GenBank Accession No. (AF04715), Florida (GenBank Accession Nos. AF260331 and AY530931), Egypt (GenBank Accession No. AY594174), and Almeria (GenBank Accession No. AJ489258). The 1,159-bp amplicon had a 97 to 99% sequence identity to the A component of Tomato mottle virus (ToMoV) Florida (GenBank Accession Nos. L14460, EF028241, and M90495) and Puerto Rico (GenBank Accession No. AY965900). Each of the eight tomato samples were shown to be infected with TYLCV and ToMoV. Symptoms of plants infected with both viruses resembled those of TYLCV because the milder symptoms of ToMoV are masked in the field by the more severe symptoms of TYLCV. To our knowledge, this is the first report of ToMoV and TYLCV in the state of Alabama. Reference: (1) M. Ghanim et al. Virology 240:295, 1998. (2) M. K. Nakhla et al. Phytopathol. Mediterr. 32:163, 1993. (3) M. R. Rojas et al. Plant Dis. 77:340, 1993.

Effect of the angiotensin II type 2-receptor gene (+1675 G/A) on left ventricular structure in humans.

OBJECTIVES: Our study goal was to analyze whether gene variants of angiotensin II type 2-receptor (AT2-R) modulate the effects of angiotensin II on the left ventricle (LV). BACKGROUND: Experimental data suggest that angiotensin II modifies ventricular growth responses via angiotensin II type 1-receptors (AT1-R) and AT2-R. METHODS: In 120 white, young male subjects with normal or mildly elevated blood pressure, we assessed plasma angiotensin II and aldosterone concentrations (RIA), 24-h urinary sodium excretion, 24-h ambulatory blood pressure and LV structure (two-dimensional guided M-mode echocardiography). The intronic +1675 G/A polymorphism of the X-chromosomal located AT2-R gene was investigated by single-strand conformational polymorphism analysis and DNA-sequencing. RESULTS: Hypertensive subjects with the A-allele had a greater LV posterior (11.0 +/- 1.3 vs. 9.9 +/- 1.3 mm, p < 0.001), septal (11.8 +/- 1.4 vs. 10.1 +/- 1.2 mm, p < 0.001) and relative wall thickness (0.44 +/- 0.06 vs. 0.39 +/- 0.06, p < 0.01) as well as LV mass index (138 +/- 23 vs. 120 +/- 13 g/m2, p < 0.001) than those with the G-allele. Confounding factors (i.e., body mass index and surface area, plasma angiotensin II, sodium excretion, systolic and diastolic ambulatory blood pressure) were similar between the two genotypes. In normotensive subjects, relative wall thickness (0.36 +/- 0.05 vs. 0.35 +/- 0.05) and LV mass index (115 +/- 21 vs. 112 +/- 17 g/m2) were nearly identical across the two genotypes, with similar confounding variables. CONCLUSIONS: Our data indicate that the X-chromosomal located +1675 G/A-polymorphism of the AT2-R gene is associated with LV structure in young male humans with early structural changes of the heart due to arterial hypertension.

Aldosterone synthase (CYP11B2) -344 C/T polymorphism is associated with left ventricular structure in human arterial hypertension.

OBJECTIVES: This study examined the association between the -344 C/T polymorphism of the human aldosterone synthase promoter and left ventricular structure in arterial hypertension. BACKGROUND: Because of conflicting results from different studies, the mechanism of such an association, if any, has not been determined. METHODS: We examined the aldosterone synthase promoter genotype in 120 young (age: 26 +/- 3 years) male, white subjects with normal or mildly elevated blood pressure. Left ventricular structural parameters and urinary sodium excretion over 24 h before and after additional oral sodium load (6 g/day over 1 week) were determined. RESULTS: Hypertensive subjects with the CC genotype had a greater left ventricular end-diastolic diameter but smaller relative wall thickness than those with the TT genotype (54 +/- 2 vs. 50 +/- 4 mm, and 0.37 +/- 0.07 vs. 0.44 +/- 0.06 mm, respectively; p < 0.05). Hypertensive subjects with the TT genotype (n = 15) had a greater increase in urinary sodium excretion after oral sodium load than those with the CC genotype (n = 11) (135 +/- 95 vs. 24 +/- 133 mmol/liter/day; p < 0.05). Serum aldosterone levels were found to be decreased after oral sodium load in hypertensive subjects with the TT and CT genotypes only (-37 +/- 45 and -38 +/- 51 pg/ml, respectively; all p < 0.01) but not in those with the CC genotype (-12 +/- 30 pg/ml, n.s.). Such differences were not found in normotensive subjects. CONCLUSIONS: Hypertensive subjects with the -344 CC genotype of the aldosterone synthase promoter are characterized by a pattern of early eccentric left ventricular hypertrophy. Differences in renal sodium handling across the genotypes might contribute to this finding.

Rapid improvement of nitric oxide bioavailability after lipid-lowering therapy with cerivastatin within two weeks.

OBJECTIVES: We investigated whether improvement of endothelial dysfunction in hypercholesterolemia can be achieved with short-term lipid-lowering therapy. BACKGROUND: Impaired endothelium-dependent vasodilation plays a pivotal role in the pathogenesis of atherosclerosis and acute coronary syndromes. METHODS: In a randomized, double-blind, placebo-controlled trial, we studied 37 patients (52 +/- 11 yrs) with low density lipoprotein cholesterol > or = 160 mg/dl (196 +/- 44 mg/dl) randomly assigned to either cerivastatin (0.4 mg/d) or placebo. Endothelium-dependent vasodilation of the forearm vasculature was measured by plethysmography and intra-arterial infusion of acetylcholine (ACh 12, 48 microg/min) and endothelium-independent vasodilation by intra-arterial infusion of nitroprusside (3.2, 12.8 microg/min). RESULTS: Low density lipoprotein cholesterol decreased after two weeks of treatment (cerivastatin -33 +/- 4% vs. placebo + 2 +/- 4%, x +/- SEM, p < 0.001). Endothelium-dependent vasodilation improved after two weeks of therapy with cerivastatin compared with baseline (ACh 12 microg/min: + 22.3 +/- 5.2 vs. + 11.2 +/- 1.9 ml/min/100 ml, p < 0.01; ACh 48 microg/min: +31.2 +/- 6.3 vs. +19.1 +/- 3.1 ml/min/100 ml, p < 0.05). In contrast, changes in forearm blood flow to ACh were similar before and after therapy in the placebo group (ACh 12 microg/min: + 12.9 +/- 3.6 vs. + 9.0 +/- 1.9 ml/min/100 ml, NS; ACh 48 microg/min: +20.7 +/- 3.7 vs. 19.4 +/- 2.9 ml/min/100 ml, NS). Endothelium-dependent vasodilation improved in comparison with placebo (ACh 48 microg/min: +203 +/- 85% [cerivastatin] vs. -26 +/- 71% [placebo], p < 0.05). This improvement in endothelium-dependent vasodilation was no longer observed when the nitric oxide-synthase inhibitor N(G)-monomethyl-L-arginine was coinfused (ACh 48 microg/min + N(G)-monomethyl-L-arginine 4 micromol/min -48 +/- 85% [cerivastatin]). CONCLUSIONS: Short-term lipid-lowering therapy with cerivastatin can improve endothelial function and NO bioavailability after two weeks in patients with hypercholesterolemia.

Hyporeninemia and hypoaldosteronism in diabetes mellitus.

The changes in plasma renin activity (PRA) and plasma aldosterone concentration (PA) in response to postural stimuli were evaluated in 12 patients with stable diabetes mellitus and in five volunteers. Seven diabetic patients had hyperkalemia, and several had renal insufficiency and neurological complications. Five diabetics and had normal serum potassium concentration, a mean creatinine clearance within the normal range, and few complications. PRA and PA were measured in these patients and in the control subjects, all of whom were receiving a diet containing 10 mEq of sodium and 50 mEq of potassium while they were in a supine position, after they were tilted to a 90 degrees position, and after upright posture for two hours. The results indicate that impaired responsiveness of PRA and PA may occur in patients with complicated and those with uncomplicated diabetes and may be responsible in part for a relatively high prevalence of hyperkalemia especially in those diabetic patients with reduced renal function.

Dual sites of inhibition by metyrapone of human adrenal steroidogenesis: correlation of in vivo and in vitro studies.

In a patient with pituitary ACTH-dependent adrenal hyperplasia (AH), the standard oral metyrapone test resulted in a decrease in "apparent 11beta-hydroxylase activity" (-48%) accompanied by an increase in "apparent cholesterol cleavage activity" (+318%). When incubated adrenal mitochondria from this patient were studied, metyrapone inhibited both 11beta-hydroxylation of labeled 11-deoxycorticosterone and cleavage of labeled cholesterol, although at 0.1 and 1.0 mM metyrapone concentrations, depression of cholesterol cleavage (23 and 54%, respectively) was less than that of 11beta-hydroxylation (62 and 84%, respectively). The inhibition of cholesterol cleavage by metyrapone (26 and 62%, at 0.1 and 1.0 mM concentrations, respectively) was also demonstrable in adrenal mitochondria from a patient with hypercorticism resulting from an ACTH-independent adrenal adenoman (AA). Metyrapone administration to AA resulted in a significant depression of both 11beta-hydroxylase (-62%) and cholesterol cleavage (-36%) "apparent activities"; when metyrapone and ACTH were given together to this patient, however, only 11beta-hydroxylase "apparent activity" diminished (-26%), while cholesterol cleavage "apparent activity" was greatly augmented (+231%), thereby simulating the results of the standard metyrapone test in AH. These data demonstrate that metyrapone inhibits both mitochondrial reactions involved in cortisol synthesis--initial cholesterol cleavage and final 11beta-hydroxylation; these effects probably result from interference by this agent with the interaction between substrate and related cytochrome P - 450. Since ACTH has a major stimulatory effect on cholesterol cleavage but not on 11beta-hydroxylation, the outcome of metyrapone administration is thus determined by whether a change in ACTH level ensues: while 11beta-hydroxylation is inhibited by metyrapone under any circumstances, total steroid output rises when a compensatory ACTH increase overcomes metyrapone inhibition of cholesterol conversion into pregnenolone and falls when metyrapone inhibition of this reaction is unopposed.

Mildly elevated homocysteine concentrations impair endothelium dependent vasodilation in hypercholesterolemic patients.

BACKGROUND: Elevated low density lipoproteins (LDL)-cholesterol and homocysteine levels have both been found to be associated with an increased risk for atherosclerotic vascular disease. To assess the effects of elevated homocysteine levels in hypercholesterolemic subjects on endothelial function, we examined basal and stimulated nitric oxide (NO) mediated vasodilation in the forearm vascular bed in hypercholesterolemic subjects with normal or elevated homocysteine levels. METHODS: Twenty-seven white subjects (age: 48 +/- 12 years) with elevated LDL-cholesterol (> or = 160 mg/dl) were divided into two groups with normal (n = 11) or mildly elevated (n = 16) homocysteine plasma concentration. We used strain gauge plethysmography to measure changes in forearm blood flow in response to intraarterial administration of increasing doses of acetylcholine (3, 12, 24, 48 microg/min), sodium nitroprusside (200, 800, 3200 ng/min), and N-monomethyl L-arginine (L-NMMA) (1, 2, 4 micromol/min). Total homocysteine plasma concentrations were determined by high performance liquid chromatography fluorimetry. RESULTS: Endothelium independent vascular relaxation tested by i.a. sodium nitroprusside and changes in forearm blood flow after i.a. L-NMMA indicating basal production and release of nitric oxide were similar between the two groups with normal or elevated homocysteine levels. In contrast, endothelium dependent vasodilation as assessed by the administration of i.a. acetylcholine differed between the groups with normal or elevated homocysteine levels for all doses tested (MANOVA P < 0.01: ACH 48 microg/min: 480 +/- 237% with normal vs 234 +/- 130% with elevated homocysteine; P < 0.002). This was significant even after taking possible covariates such as age, blood pressure, body mass index, LDL-, high density lipoproteins (HDL)-cholesterol, and trigylcerides into account (MANOVA P < 0.02). CONCLUSIONS: From our study we conclude that homocysteine impairs endothelium dependent vasodilation in subjects with elevated LDL-cholesterol levels. The most intriguing finding is that even mildly elevated homocysteine levels seem to be of crucial importance for deterioration of endothelial function, especially if other cardiovascular risk factors such as hypercholesterolemia preexist.

825T allele of the G-protein beta3 subunit gene (GNB3) is associated with impaired left ventricular diastolic filling in essential hypertension.

OBJECTIVE: Recently, a novel C825T polymorphism in the gene (GNB3) encoding for the G-protein beta3 subunit was identified. The 825T allele is associated with the generation of a novel splice variant, enhanced intracellular signal transduction, and arterial hypertension. In this study, we investigated the impact of the 825T allele on left ventricular structure and function in mild to moderate essential hypertensive subjects. METHODS: In 34 white patients with established mild to moderate essential hypertension (World Health Organization stage I or II, mean age 52 +/- 9 years) genotype analysis of GNB3 C825T polymorphism, insertion/deletion polymorphism of the ACE gene and 1166 A/C polymorphism of the AT1 receptor gene was performed. In each patient, 24 h ambulatory blood pressure measurement (SpaceLabs 90207) and two-dimensional guided M-mode echocardiography combined with Doppler sonography were performed. RESULTS: In our homogenous study group, the GNB3 825T allele was not associated with casual and 24 h ambulatory blood pressure (CC versus TC/TT: 144 +/- 13/92 +/- 8 versus 151 +/- 14/97 +/- 7 and 143 +/- 11/92 +/- 7 versus 150 +/- 16/ 96 +/- 9 mmHg, respectively) or parameters of left ventricular structure (relative wall thickness: CC versus TC/TT, 0.48 +/- 0.1 versus 0.46 +/- 0.1; left ventricular mass: CC versus TC/TT, 281 +/- 65 versus 299 +/- 80 g). However, transmitral flow variables reflecting left ventricular diastolic filling were impaired in patients expressing the TC/TT genotype (ratio of peak late (A) to early (E) velocities: CC versus TC/TT, 0.95 +/- 0.24 versus 1.2 +/- 0.26, P< 0.02; velocity time integrals A/E: CC versus TC/TT, 0.57 +/- 0.16 versus 0.76 +/- 0.23, P< 0.01) while all co-variables such as age, body mass index, ambulatory blood pressure, heart rate and end-diastolic volume were similar between the two groups. If patients were stratified according to the I/D polymorphism of the ACE gene and the A1166C polymorphism of the AT1 receptor gene, no differences in blood pressure, left ventricular structure or systolic and diastolic function of the left ventricle were found between different genotypes. CONCLUSION: The GNB3 825T allele was associated with impaired left ventricular diastolic filling in hypertensive subjects in this study. Since alterations in left ventricular filling have been identified as an early marker of hypertensive heart disease, the GNB3 C825T polymorphism may influence cardiac adaptation to increased afterload.

Low-density lipoprotein-cholesterol determines vascular responsiveness to angiotensin II in normocholesterolaemic humans.

OBJECTIVE: Both LDL-cholesterol and angiotensin II have been shown to increase the risk for and severity of cardiovascular disease. In hypercholesterolaemia, experimental studies have demonstrated an increased angiotensin type 1 (AT1) receptor expression on vascular smooth muscle cells and an increased vascular responsiveness to vasopressors has been documented in humans. We investigated in a normocholesterolaemic young population whether vascular responsiveness to angiotensin II (Ang II) infusion depends on LDL-cholesterol serum levels in the systemic and renal circulation. DESIGN AND METHODS: Changes in systolic and diastolic blood pressure (deltaBP) to Ang II infusion (0.5 and 3.0 ng/kg per min) were investigated in 103 normocholesterolaemic (LDL-cholesterol < 160 mg/dl) young white men (26+/-3 years; 24 h BP: 128+/-10/75+/-7 mmHg) without cardiovascular disease. According to their LDL-cholesterol levels, participants were classified into tertiles (lower tertile < 85 mg/dl, middle tertile 85-111 mg/dl, upper tertile > 111 mg/dl). RESULTS: Blood pressure (BP) responses to Ang II infusion 3.0 ng/kg per min were enhanced in the group with the highest LDL-cholesterol levels (delta systolic BP: +12.8+/-6.7, +13.2+/-8.6, +17.9+/-9.6, P < 0.02; delta diastolic BP: +11.1+/-5.8, +11.5+/-6.5, +16.5+/-8.3, P < 0.01, for the lower, middle and upper tertiles, respectively). This holds true when baseline BP was taken into account as a confounding covariable (P < 0.015). BP responses to Ang II infusion were related to LDL-cholesterol serum levels (delta systolic BP: r = 0.26, P = 0.01; delta diastolic BP: r = 0.32, P = 0.001). In multiple stepwise regression analysis, LDL-cholesterol emerged as the strongest determinant of vascular responsiveness to Ang II (delta systolic BP: P < 0.01; delta diastolic BP: P < 0.001). CONCLUSION: In young male subjects, responsiveness to Ang II is determined by the LDL-cholesterol serum level even in the normal range of LDL-cholesterol, thereby potentially contributing to the cardiovascular risk of LDL-cholesterol even within the so-called normal range.

Lack of association between polymorphisms of angiotensin II receptor genes and response to short-term angiotensin II infusion.

OBJECTIVES: The physiological effects of polymorphisms of the renin-angiotensin-aldosterone system (RAAS) are poorly understood. Long-term effects of genetic variants can be studied in cross-sectional linkage studies. In this study, we examined the short-term effects of genetic polymorphisms of the angiotensin II AT1 - and AT2-receptor subtypes in humans by means of angiotensin II infusion. METHODS: In 120 male, white, young (26 +/- 3 years) subjects with normal or mildly elevated blood pressure, changes in mean arterial blood pressure, aldosterone levels, glomerular filtration rate (GFR), and renal plasma flow (RPF) were measured in response to angiotensin II infusion (0.5 ng/kg per min and 3.0 ng/kg per min, each over 30 min). The -2228 G/A polymorphism of the AT1-receptor gene, and the +1675 G/A polymorphism of the AT2-receptor gene were determined by restriction digestion and single strand conformation polymorphism analysis, respectively. RESULTS: Infusion of angiotensin II resulted in an increase in mean arterial pressure, serum aldosterone levels and GFR, and in a decrease in RPF (all P< 0.001). However, at similar baseline mean arterial pressure, aldosterone levels, and renal haemodynamics, the response to angiotensin II did not significantly differ across the AT1 - and AT2-receptor genotypes with the sample size of our study being adequate to detect relevant differences across the genotypes with a power of > 90% for all parameters. CONCLUSIONS: The response to angiotensin II infusion does not differ across the the AT1- and AT2-receptor genotypes examined in our study. However, long-term effects of variants of angiotensin II receptor genes cannot be ruled out with this approach.

Prospective analysis of the value of 24-hour ambulatory blood pressure on renal function after kidney transplantation.

BACKGROUND: No prospective study has been performed to determine the prognostic value of 24-hr ambulatory blood pressure (24-hr ABP) versus casual blood pressure (CBP) in patients after kidney transplantation. We have addressed this issue by analyzing renal graft function in patients for the first 5 years after transplantation. METHODS: The 24-hr ABP (SpaceLabs 90207) was monitored 6 and 18 months after transplantation in 46 renal transplant recipients without any acute episodes of rejection. Combined study endpoints were death of patients, need for dialysis, second transplantation, and doubling of serum creatinine. RESULTS: Six months after transplantation systolic and diastolic 24-hr ABP correlated with serum creatinine (r=0.41, P=0.005 and r=0.37, P<0.01, respectively) although CBP did not. Divided into tertiles according to average 24-hr ABP (lower tertile: < or =91 mmHg; middle tertile: 92-97 mmHg; upper tertile: > or =98 mmHg) serum creatinine significantly differed between the three groups (1.26 +/- 0.38 vs. 1.32 +/- 0.25 vs. 1.65 +/- 0.39 mg/dl, respectively; analysis of variance, P< 0.01). Confounding factors of renal function such as age, body weight, cold and warm ischemic time, cytomegaly virus status, methylprednisone and cyclosporine dosages, cyclosporine concentrations, as well as concomitant antihypertensive medication did not differ among the three groups. In the long-term follow-up (5 years), combined endpoints were reached in 3 of 15 of the lower tertile group, in 3 of 15 of the median tertile group, and in 8 of 16 of the upper tertile group (log-rank test, P<0.01). No relation to long-term out come was found when patients were stratified according to their CBP. CONCLUSION: In our small but homogenous study cohort 24-hr ABP was more closely related to renal function in patients after transplantation than CBP suggesting that 24-hr ABP is superior for evaluation of hypertension-related renal graft dysfunction.

Nuclear diameter in the anterior pituitary gland of the rat: effects of estrogen, bromocriptine, and haloperidol.

Nuclear diameter, DNA synthesis, and mitotic index in the pituitary cells of male rats and serum prolactin were measured after a period of 8 days of treatment with a dopamine agonist and an antagonist given with and without estrogen. In the absence of estrogen, the dopamine agonist, bromocriptine, diminished the mean nuclear diameter of the pituitary cells and lowered pituitary DNA synthesis, and the dopamine-blocking agent haloperidol had no effect. Estrogen increased the mean nuclear diameter, pituitary mitotic index, and DNA synthesis. Bromocriptine prevented the estrogen-induced increase in mean nuclear diameter and pituitary DNA synthesis and mitotic index were lowered. Haloperidol augmented the estrogen-induced increase in mean nuclear diameter, pituitary DNA synthesis, and mitotic index. Positive correlations were obtained between mean nuclear diameter and DNA synthesis and serum prolactin. It was concluded that nuclear diameter was influenced by both DNA synthesis and secretory activity in pituitary cells.

Onset of oestrogen-induced prolactin secretion and DNA synthesis by the rat pituitary gland.

The times of onset of oestrogen-induced prolactin secretion and DNA synthesis were studied in the pituitary gland of the male rat. At intervals from 3 to 96 h after injection of 10 mg diethylstilboestrol dipropionate, serum and pituitary prolactin concentrations were measured by radioimmunoassay and pituitary DNA synthesis by incorporation of [3H]-thymidine in vitro. Serum prolactin was raised significantly from 6 h onwards and DNA synthesis was increased from 30 h onwards. Pituitary prolactin concentration began to increase at 30 h. Significant correlations were obtained between serum prolactin and DNA synthesis from 24 to 72 h but not during the period of prolactin secretion from 6 to 24 h.

DNA synthesis and depletion of prolactin in the pituitary gland of the male rat.

Haloperidol, bromocriptine and diethylstilboestrol dipropionate were given in various régimes to male rats to determine their effects on pituitary DNA synthesis, prolactin secretion and growth hormone secretion. Haloperidol increased serum prolactin but did not stimulate pituitary DNA synthesis or reduce pituitary prolactin concentrations. Haloperidol potentiated the effects of oestrogen on serum prolactin and on pituitary DNA synthesis; pituitary prolactin concentrations were greatly reduced, and growth hormone secretion was slightly inhibited. The inhibitory effects of bromocriptine in oestrogen-stimulated rats were demonstrated by smaller pituitary weights and decreased DNA synthesis; serum prolactin levels were lowered and pituitary prolactin concentrations were increased. Haloperidol, given to rats treated with oestrogen and bromocriptine, reversed the inhibitory effects of bromocriptine on DNA synthesis and serum prolactin; pituitary prolactin concentrations fell to well below normal. The results suggest that the haloperidol potentiation of oestrogen-induced pituitary DNA synthesis may depend upon stimulation of prolactin secretion together with reduction of intracellular prolactin levels.