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.

Clinical Practice Guidelines for Sustained Neuromuscular Blockade in the Adult Critically Ill Patient

"OBJECTIVE: To update the 2002 version of ""Clinical practice guidelines for sustained neuromuscular blockade in the adult critically ill patient."" DESIGN: A Task Force comprising 17 members of the Society of Critical Medicine with particular expertise in the use of neuromuscular-blocking agents; a Grading of Recommendations Assessment, Development, and Evaluation expert; and a medical writer met via teleconference and three face-to-face meetings and communicated via e-mail to examine the evidence and develop these practice guidelines. Annually, all members completed conflict of interest statements; no conflicts were identified. This activity was funded by the Society for Critical Care Medicine, and no industry support was provided. METHODS: Using the Grading of Recommendations Assessment, Development, and Evaluation system, the Grading of Recommendations Assessment, Development, and Evaluation expert on the Task Force created profiles for the evidence related to six of the 21 questions and assigned quality-of-evidence scores to these and the additional 15 questions for which insufficient evidence was available to create a profile. Task Force members reviewed this material and all available evidence and provided recommendations, suggestions, or good practice statements for these 21 questions. RESULTS: The Task Force developed a single strong recommendation: we recommend scheduled eye care that includes lubricating drops or gel and eyelid closure for patients receiving continuous infusions of neuromuscular-blocking agents. The Task Force developed 10 weak recommendations. 1) We suggest that a neuromuscular-blocking agent be administered by continuous intravenous infusion early in the course of acute respiratory distress syndrome for patients with a PaO2/FIO2 less than 150. 2) We suggest against the routine administration of an neuromuscular-blocking agents to mechanically ventilated patients with status asthmaticus. 3) We suggest a trial of a neuromuscular-blocking agents in life-threatening situations associated with profound hypoxemia, respiratory acidosis, or hemodynamic compromise. 4) We suggest that neuromuscular-blocking agents may be used to manage overt shivering in therapeutic hypothermia. 5) We suggest that peripheral nerve stimulation with train-of-four monitoring may be a useful tool for monitoring the depth of neuromuscular blockade but only if it is incorporated into a more inclusive assessment of the patient that includes clinical assessment. 6) We suggest against the use of peripheral nerve stimulation with train of four alone for monitoring the depth of neuromuscular blockade in patients receiving continuous infusion of neuromuscular-blocking agents. 7) We suggest that patients receiving a continuous infusion of neuromuscular-blocking agent receive a structured physiotherapy regimen. 8) We suggest that clinicians target a blood glucose level of less than 180 mg/dL in patients receiving neuromuscular-blocking agents. 9) We suggest that clinicians not use actual body weight and instead use a consistent weight (ideal body weight or adjusted body weight) when calculating neuromuscular-blocking agents doses for obese patients. 10) We suggest that neuromuscular-blocking agents be discontinued at the end of life or when life support is withdrawn. In situations in which evidence was lacking or insufficient and the study results were equivocal or optimal clinical practice varies, the Task Force made no recommendations for nine of the topics. 1) We make no recommendation as to whether neuromuscular blockade is beneficial or harmful when used in patients with acute brain injury and raised intracranial pressure. 2) We make no recommendation on the routine use of neuromuscular-blocking agents for patients undergoing therapeutic hypothermia following cardiac arrest. 3) We make no recommendation on the use of peripheral nerve stimulation to monitor degree of block in patients undergoing therapeutic hypothermia. 4) We make no recommendation on the use of neuromuscular blockade to improve the accuracy of intravascular-volume assessment in mechanically ventilated patients. 5) We make no recommendation concerning the use of electroencephalogram-derived parameters as a measure of sedation during continuous administration of neuromuscular-blocking agents. 6) We make no recommendation regarding nutritional requirements specific to patients receiving infusions of neuromuscular-blocking agents. 7) We make no recommendation concerning the use of one measure of consistent weight over another when calculating neuromuscular-blocking agent doses in obese patients. 8) We make no recommendation on the use of neuromuscular-blocking agents in pregnant patients. 9) We make no recommendation on which muscle group should be monitored in patients with myasthenia gravis receiving neuromuscular-blocking agents. Finally, in situations in which evidence was lacking or insufficient but expert consensus was unanimous, the Task Force developed six good practice statements. 1) If peripheral nerve stimulation is used, optimal clinical practice suggests that it should be done in conjunction with assessment of other clinical findings (e.g., triggering of the ventilator and degree of shivering) to assess the degree of neuromuscular blockade in patients undergoing therapeutic hypothermia. 2) Optimal clinical practice suggests that a protocol should include guidance on neuromuscular-blocking agent administration in patients undergoing therapeutic hypothermia. 3) Optimal clinical practice suggests that analgesic and sedative drugs should be used prior to and during neuromuscular blockade, with the goal of achieving deep sedation. 4) Optimal clinical practice suggests that clinicians at the bedside implement measure to attenuate the risk of unintended extubation in patients receiving neuromuscular-blocking agents. 5) Optimal clinical practice suggests that a reduced dose of an neuromuscular-blocking agent be used for patients with myasthenia gravis and that the dose should be based on peripheral nerve stimulation with train-of-four monitoring. 6) Optimal clinical practice suggests that neuromuscular-blocking agents be discontinued prior to the clinical determination of brain death."

Paradoxical effect of gonadotrophin-inhibiting hormone to negatively regulate neuropeptide Y neurones in mouse arcuate nucleus.

Regulation of reproduction and energy homeostasis are linked, although our understanding of the central neural mechanisms subserving this connection is incomplete. Gonadotrophin-inhibiting hormone (GnIH) is a neuropeptide that negatively regulates reproduction and stimulates food intake. Neuropeptide Y (NPY) and products of the pro-opiomelanocortin (POMC) precursor (ß-endorphin melanocortins) are appetite regulating peptides produced in the neurones of the arcuate nucleus; these peptides also regulate reproduction. In the present study, we determined the effects of GnIH on NPY and POMC neurones. Using brain slices from mice with transgenes for fluorescent tags in the two types of neurone and patch clamp electrophysiology, a predominant inhibitory effect of GnIH was observed. GnIH (100 nM) inhibited the firing rate in POMC cells, confirming the results of previous studies and consistent with the stimulatory effect of GnIH on food intake. Paradoxically (i.e. because both GnIH and NPY stimulate food intake), GnIH also had a predominantly inhibitory effect on action potential activity in NPY cells. GnIH also inhibited the secretion of NPY and α-melanocyte-stimulating hormone secretion in incubated hypothalamic blocks. GnIH (100 ng) injected into the cerebral ventricles of mice did not increase the number of NPY cells that were positively immunostained for c-Fos. Finally, dual label immunocytochemistry showed that 20% of NPY neurones had close contacts from GnIH fibres/varicosities. In conclusion, we confirm a negative effect of GnIH on POMC cells and demonstrate a paradoxical reduction of electrophysiological and functional activity in NPY cells.

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.

Guidelines for the use of an insulin infusion for the management of hyperglycemia in critically ill patients

Objective: To evaluate the literature and identify important aspects of insulin therapy that facilitate safe and effective infusion therapy for a defined glycemic end point. Methods: Where available, the literature was evaluated using Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) methodology to assess the impact of insulin infusions on outcome for general intensive care unit patients and those in specific subsets of neurologic injury, traumatic injury, and cardiovascular surgery. Elements that contribute to safe and effective insulin infusion therapy were determined through literature review and expert opinion. The majority of the literature supporting the use of insulin infusion therapy for critically ill patients lacks adequate strength to support more than weak recommendations, termed suggestions, such that the difference between desirable and undesirable effect of a given intervention is not always clear. Recommendations: The article is focused on a suggested glycemic control end point such that a blood glucose ≥150 mg/dL triggers interventions to maintain blood glucose below that level and absolutely <180 mg/dL. There is a slight reduction in mortality with this treatment end point for general intensive care unit patients and reductions in morbidity for perioperative patients, postoperative cardiac surgery patients, post-traumatic injury patients, and neurologic injury patients. We suggest that the insulin regimen and monitoring system be designed to avoid and detect hypoglycemia (blood glucose ≤70 mg/dL) and to minimize glycemic variability. Important processes of care for insulin therapy include use of a reliable insulin infusion protocol, frequent blood glucose monitoring, and avoidance of finger-stick glucose testing through the use of arterial or venous glucose samples. The essential components of an insulin infusion system include use of a validated insulin titration program, availability of appropriate staffing resources, accurate monitoring technology, and standardized approaches to infusion preparation, provision of consistent carbohydrate calories and nutritional support, and dextrose replacement for hypoglycemia prevention and treatment. Quality improvement of glycemic management programs should include analysis of hypoglycemia rates, run charts of glucose values <150 and 180 mg/dL. The literature is inadequate to support recommendations regarding glycemic control in pediatric patients. Conclusions: While the benefits of tight glycemic control have not been definitive, there are patients who will receive insulin infusion therapy, and the suggestions in this article provide the structure for safe and effective use of this therapy.

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.

Isotope shift in the dielectronic recombination of three-electron ANd57+.

Isotope shifts in dielectronic recombination spectra were studied for Li-like (A)Nd(57+) ions with A=142 and A=150. From the displacement of resonance positions energy shifts deltaE(142 150)(2s-2p(1/2))=40.2(3)(6) meV [(stat)(sys)] and deltaE(142 150)(2s-2p(3/2))=42.3(12)(20) meV of 2s-2p(j) transitions were deduced. An evaluation of these values within a full QED treatment yields a change in the mean-square charge radius of (142 150)deltar(2)=-1.36(1)(3) fm(2). The approach is conceptually new and combines the advantage of a simple atomic structure with high sensitivity to nuclear size.

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.

Subtotal nephrectomy impairs ischemia-induced angiogenesis and hindlimb re-perfusion in rats.

Kidney disease is associated with increased cardiovascular morbidity, but underlying mechanisms are poorly understood. We tested the hypothesis that chronic renal insufficiency impairs angioadaptation in a rat model of hindlimb ischemia. Twenty male Sprague-Dawley rats (8 weeks old) underwent subtotal nephrectomy (5/6SNX) or sham surgery (each n=10). Ten weeks later, unilateral hindlimb ischemia was induced in all animals. Hindlimb perfusion was assessed by laser Doppler perfusion imaging and fluorescent microsphere injection studies 2 weeks after surgery. Ischemia-induced angiogenesis was measured by analyzing capillary density using CD31 immunofluorescence. Expression of vascular endothelial growth factor (VEGF), its receptors (VEGFRs) and inducible as well as endothelial nitric oxide (NO) synthase was measured by real-time reverse transcription-polymerase chain reaction. Laser Doppler hindpaw perfusion was significantly reduced in 5/6SNX compared to sham-operated animals. Impaired hindlimb re-perfusion in 5/6SNX vs control rats was confirmed by fluorescent microsphere injection studies (relative perfusion of ischemic vs non-ischemic limb: 68.9+/-6.4 vs 92.4+/-3.6%, P=0.005). Ischemic skeletal muscle neovascularization increased to a greater extent in sham-operated compared to 5/6SNX rats (69+/-8 vs 29+/-7%, P<0.05). VEGF and VEGFR-1/2 mRNA expression increased in ischemic hindlimbs of control rats, whereas no change or a decrease was observed in 5/6SNX. In contrast, inducible and endothelial NO synthase expression did not significantly differ between sham and 5/6SNX rats. Chronic renal insufficiency impairs angiogenesis and limb perfusion in a rat hindlimb ischemia model. Impaired angioadaptation may contribute to the poor prognosis of patients with renal failure suffering from peripheral arterial disease.

The presence of erythropoietin receptors in the human peripheral nervous system.

Erythropoietin (EPO) is a well-known hematopoietic factor and a major determinant of tissue oxygenation. EPO receptors have been identified on a wide variety of non-erythroid cell types including human central nervous system and peripheral nervous system of animal models. The presence or function of EPO receptors in human peripheral nervous system is unknown. By examining nerve segments from radicular and autonomic nerves using immunohistochemical methods, we demonstrated the presence of EPO receptors on myelin sheath of radicular nerves in the human peripheral nervous system.

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.

Effects of endothelin receptor antagonists on the progression of diabetic nephropathy.

BACKGROUND: Diabetic nephropathy is the leading cause of end-stage renal disease in European countries and is associated with an enhanced renal synthesis of endothelin (ET)-1. ETs are - beside their potent vasoconstrictor properties - very potent profibrotic acting paracrine hormones especially in the kidney. METHODS: We analyzed in rats with streptozotocin-induced diabetes the effects of an ETA-type (ETA) receptor antagonist (LU 135252) in comparison to a combined ETA/ETB receptor antagonist (LU 224332) on the expression of interstitial and glomerular collagen type I, III and IV as well as on fibronectin and laminin by quantitative immunohistochemistry using a computer-aided image analysis system. Global glomerular matrix deposition was analyzed after PAS staining. In addition to the morphometric examination of the kidneys, we also investigated GFR, urinary albumin and total protein excretion. The diabetic rats were treated for 36 weeks. RESULTS: Treatment with either LU 135252 or LU 224332 normalized the amount of PAS-positive material within the glomeruli. The expression of glomerular fibronectin and type IV collagen was increased 36 weeks after induction of diabetes. The overexpression of these two matrix proteins within the glomeruli of diabetic rats was completely abolished by both ET receptor antagonists, whereas protein excretion was only reduced by about 50% as compared to diabetic rats without treatment. CONCLUSION: The present study indicates that ETA receptor antagonists as well as combined ETA/ETB receptor antagonists reduce proteinuria and completely normalize the renal matrix protein expression in hyperglycemic rats with streptozotocin-induced diabetes. The antifibrotic effect seems to be mediated via the ETA receptor. ET receptor antagonists might be a new approach in the treatment of diabetic nephropathy.

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.

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.