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Critical limb ischemia (CLI) is associated with skeletal muscle damage. However, the pathophysiology of the muscle damage is poorly understood. Toll-like receptors (TLR) have been attributed to play a role in ischemia-induced tissue damage but their role in skeletal muscle damage in CLI is unknown. TLR2 and TLR6 expression was found to be upregulated in skeletal muscle of patients with CLI. In vitro, ischemia led to upregulation of TLR2 and TLR6 by myotubes, and activation of the downstream TLR signaling pathway. Ischemia-induced activation of the TLR signaling pathway led to secretion of the pro-inflammatory cytokine interleukin-6 and muscle apoptosis, which were abrogated by neutralising TLR2 and TLR6 antibodies. Our study demonstrates that TLR2 and TLR6 are upregulated in ischemic muscle and play a role in ischemia-induced muscle damage. Thus, manipulating the TLR pathway locally may be of potential therapeutic benefit.

Objective: To compare three-dimensional (3D) ClinCheck™ models with the subjects' actual 3D posttreatment models using the American Board of Orthodontics Objective Grading System (OGS)., Materials and Methods: This prospective, within-subject study included 27 consecutive cases treated with aligner therapy. The posttreatment plaster models taken immediately after treatment were scanned and converted to stereolithography (STL) files; the ClinCheck models were also converted to STL format. MeshLab software was used to measure the seven components of the OGS, including alignment, marginal ridges, buccolingual inclinations, occlusal contacts, occlusal relationships, overjet and interproximal contacts. An overall OGS deduction score was also calculated., Results: Compared with the posttreatment models, the ClinCheck models showed significantly (P  =  .016) fewer overall OGS point deductions (24 vs 15). These overall differences were due to significantly (P < .05) more deductions among the posttreatment models than the ClinCheck models for alignment (4.0 vs 1.0 deductions), buccolingual inclinations (4.0 vs 3.0 deductions), occlusal contacts (3.0 vs 2.0 deductions), and occlusal relations (4.0 vs 2.0 deductions)., Conclusion: The ClinCheck models do not accurately reflect the patients' final occlusion, as measured by the OGS, at the end of active treatment.

Hepatitis C virus (HCV) is increasingly common among human immunodeficiency virus (HIV)-infected men who have sex with men. We evaluated the efficacy of HCV core antigen in diagnosing acute HCV in an HIV-infected cohort. Compared with HCV polymerase chain reaction, core antigen proved sensitive (100%) and specific (97.9%). As a quick, simple, and cost-effective test, it has considerable utility in screening for acute HCV., (© The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)

Objective: To compare the time efficiency of aligner therapy (ALT) and conventional edgewise braces (CEB) based on large samples of patients treated by the same highly experienced orthodontist, with the same treatment goals for both groups of patients., Materials and Methods: The retrospective portion of the study evaluated 150 CEB patients who were matched, based on mandibular crowding and number of rotated teeth, to 150 ALT patients. All records were obtained at one orthodontist's office. All of the patients had mild-to-moderate Class I malocclusions (≤5 mm incisor crowding) and were treated nonextraction. Age, gender, total treatment time, total number of appointments, types of appointments, materials used, mandibular crowding, and number of rotated teeth were recorded from the patients' records. The prospective portion of the study timed the various types of appointments for both treatments with a stopwatch., Results: Compared to ALT, CEB required significantly (P<.01) more visits (approximately 4.0), a longer treatment duration (5.5 months), more emergency visits (1.0), greater emergency chair time (7.0 minutes), and greater total chair time (93.4 minutes). However, ALT showed significantly (P<.01) greater total material costs and required significantly more total doctor time than CEB (P<.01)., Conclusions: Whether the greater time efficiency of ALT offsets the greater material costs and doctor time required depends on the experience of the orthodontist and the number of ALT case starts.

Rates of osteoporosis and fracture may be increased in HIV but there are few UK data. Our aim was to examine the prevalence of and risk factors for osteoporosis and fractures among a homogeneous cohort of well-characterized HIV-infected men. In total, 168 men were recruited, median age 45 years, 37 combination antiretroviral therapy (cART) naïve, 46 with <3 years cART exposure and 85 cART-exposed longer term (median >10 years). All participants provided information on bone health and underwent DEXA scanning. Osteopenia was found in 58% of subjects and osteoporosis in 12%; 14% reported fractures since HIV diagnosis. Number of fractures since HIV diagnosis was significantly increased among those with osteoporosis (OR 3.5, 95% CI 1.2-10.4, p = 0.018). Duration of infection greater than 13 years was significantly associated with osteoporosis. Duration of cART was associated in univariate but not multivariate analyses. Strategies to prevent osteoporosis and fractures in HIV will require attention to viral and lifestyle factors and not just cART.

Unlabelled: There is growing awareness that HIV infection is associated with low bone mass and fracture. DXA is a relatively scarce resource. Therefore, we evaluated two tools: peripheral DXA (pDXA) at the forearm and Fracture Risk Assessment Tool (FRAX®) to see which performed best at identifying men who should undergo DXA. In this setting, neither pDXA nor FRAX® showed good sensitivity and specificity for DXA., Purpose: Infection with human immunodeficiency virus (HIV) is associated with an increased risk of low bone mineral density (BMD) and fractures. European guidance advocates screening using the FRAX® tool at diagnosis, on initiation of antiretroviral therapy and biannually thereafter in order to decide the need for DXA scanning. This cross-sectional study evaluates the performance of FRAX® and compares its sensitivity and specificity with that of another screening tool, peripheral forearm DXA (pDXA)., Methods: HIV-infected men with varying exposure to antiretroviral therapies were recruited. FRAX® scores were calculated for all participants and everybody underwent pDXA scanning. Femoral neck and lumbar spine BMD was acquired on a Hologic QDR machine by an assessor blinded to the results of the FRAX® and pDXA., Results: One hundred and sixty-eight men (median age 45 years) were recruited with a median duration since HIV diagnosis of 74 months. In total, 21 % of subjects had either osteoporosis (aged ≥50 years) or BMD lower than expected for age (aged <50 years), according to axial DXA. Using a pDXA screening threshold of T ≤ -0.9, sensitivity was high (91 %) in defining those with the worst BMD on axial DXA but with poorer specificity (33 %). Alternately, using a threshold of T ≤ -2.7 reduced sensitivity (34 %) with an increase in specificity (91 %). FRAX® with HIV included as a secondary risk factor had poor sensitivity (31 %) and specificity (74 %) for detecting those with the poorest BMD on axial DXA., Conclusion: In this setting, neither pDXA scanning nor FRAX® was sensitive and specific for low bone mass on DXA and neither was performance much improved by using both screening tools. Prospective studies with fracture as an outcome are required in HIV.

Abstract Objective: To compare the time efficiency of aligner therapy (ALT) and conventional edgewise braces (CEB) based on large samples of patients treated by the same highly experienced orthodontist, with the same treatment goals for both groups of patients. Materials and Methods: The retrospective portion of the study evaluated 150 CEB patients who were matched, based on mandibular crowding and number of rotated teeth, to 150 ALT patients. All records were obtained at one orthodontist's office. All of the patients had mild-to-moderate Class I malocclusions (≤5 mm incisor crowding) and were treated nonextraction. Age, gender, total treatment time, total number of appointments, types of appointments, materials used, mandibular crowding, and number of rotated teeth were recorded from the patients' records. The prospective portion of the study timed the various types of appointments for both treatments with a stopwatch. Results: Compared to ALT, CEB required significantly (P < .01) more visits (approximately 4.0), a longer treatment duration (5.5 months), more emergency visits (1.0), greater emergency chair time (7.0 minutes), and greater total chair time (93.4 minutes). However, ALT showed significantly (P < .01) greater total material costs and required significantly more total doctor time than CEB (P < .01). Conclusions: Whether the greater time efficiency of ALT offsets the greater material costs and doctor time required depends on the experience of the orthodontist and the number of ALT case starts.

We report here the first two cases of hepatobiliary pathology in HIV-positive men following recreational use of ketamine: >1 g/day over a 12-month period while on ritonavir-based antiretroviral therapy. Presentation in each case was acute with nausea, vomiting and epigastric pain. Alanine aminotransferase was raised at 3.2× and 10.1 × upper limit of normal and alkaline phosphatase was raised at 1.7× and 2.5 × ULN for cases 1 and 2, respectively. Magnetic resonance cholangiopancreatography showed dilatation of the common bile duct; case 1, 18 mm and case 2, 14 mm with no ductal obstruction on endoscopic retrograde cholangiopancreatography. The symptoms resolved, common bile duct dilatation and liver function improved on discontinuation of ketamine use. Time to development of symptoms is shorter than reported in HIV-negative cases (12 months vs. 4 years) which may be explained by an interaction between ketamine and ritonavir.

Aim: Endothelial dysfunction is a marker for development and progression of atherosclerosis. Statin therapy improves endothelial function in cardiovascular patients by reducing LDL-cholesterol and by pleiotropic effects. B-group vitamin supplementation restores endothelial function mainly by reducing homocysteine-induced oxidative stress. Thus, we evaluated the effect of rosuvastatin, B-group vitamins and their combination on endothelial function in high-risk cardiovascular patients., Methods: Thirty-six patients with cardiovascular disease were randomly, double-blinded assigned to either rosuvastatin 10 mg (group R, n = 18) or vitamin supplementation consisting of folic acid 1 mg, vitamin B12 0.4 mg, and B6 10 mg (group V, n = 18) for 6 weeks. After 6 weeks all patients received rosuvastatin and vitamin supplementation in combination for additional 6 weeks. Endothelial function was assessed by flow-mediated vasodilation (FMD) at baseline and after 6- and 12-week treatment., Results: At baseline, FMD, plasma lipids, vitamins, and homocysteine were comparable between both groups. After 6 weeks, FMD improved in both groups (from 4.4 ± 1.6 to 6.9 ± 1.4% group R, P= 0.0004 and from 4.9 ± 1.8 to 6.4 ± 1.8% group V, P= 0.0002). This improvement in FMD was mainly associated with a decrease of plasma lipids in group R and a decrease of homocysteine in group V. After 12 weeks, the combined therapy with rosuvastatin and vitamins further improved FMD to the normal range in 26/33 patients compared to 5/36 at baseline (P < 0.0001)., Conclusions: In conclusion, both treatments, rosuvastatin and B-group vitamin supplementation, improved endothelial function in high-risk cardiovascular patients. The combination of both therapies had an additive effect on endothelial function suggesting different mechanisms of action., (© 2011 Blackwell Publishing Ltd.)

Aims: A marked increase in HDL notwithstanding, the cholesterol ester transfer protein (CETP) inhibitor torcetrapib was associated with an increase in all-cause mortality in the ILLUMINATE trial. As underlying mechanisms remain elusive, the present study was designed to delineate potential off-target effects of torcetrapib., Methods and Results: Spontaneously hypertensive rats (SHRs) and Wistar-Kyoto (WKY) rats were treated with torcetrapib (100 mg/kg/day; SHR-T and WKY-T) or placebo (SHR-P and WKY-P) for 3 weeks. Blood pressure transiently increased during the first 3 days of torcetrapib administration in SHRs and returned to baseline thereafter despite continued drug administration. Acetylcholine-induced endothelium-dependent relaxations of aortic rings were markedly impaired, and endothelial nitric oxide synthase (eNOS) mRNA and protein were down-regulated after 3 weeks of torcetrapib treatment in SHR (P < 0.0001, <0.01, and <0.05, resp. vs. SHR-P). Torcetrapib reduced NO release in cultured aortic endothelial cells (P < 0.01 vs. vehicle-treated cells) and increased generation of reactive oxygen species in aortas of SHR-T (P < 0.05, vs. SHR-P). Vascular reactivity to endothelin-1 (ET-1) and aortic ET-1 tissue content were increased in SHR-T (P < 0.05 vs. SHR-P). Importantly, the ET-1 receptor A/B (ET(A/B)) antagonist bosentan normalized endothelial function in SHR-T (P < 0.05)., Conclusion: Torcetrapib induces a sustained impairment of endothelial function, decreases eNOS mRNA, protein as well as NO release, stimulates vascular ROS and ET production, an effect that is prevented by chronic ET(A/B)-receptor blockade. These unexpected off-target effects of torcetrapib need to be ruled out in the clinical development of novel CETP inhibitors, particularly before a large patient population at increased cardiovascular risk is exposed to these compounds.

Toll-like receptors (TLRs) are key receptors of the innate immune system which are expressed on immune and nonimmune cells. They are activated by both pathogen-associated molecular patterns and endogenous ligands. Activation of TLRs culminates in the release of proinflammatory cytokines, chemokines, and apoptosis. Ischaemia and ischaemia/reperfusion (I/R) injury are associated with significant inflammation and tissue damage. There is emerging evidence to suggest that TLRs are involved in mediating ischaemia-induced damage in several organs. Critical limb ischaemia (CLI) is the most severe form of peripheral arterial disease (PAD) and is associated with skeletal muscle damage and tissue loss; however its pathophysiology is poorly understood. This paper will underline the evidence implicating TLRs in the pathophysiology of cerebral, renal, hepatic, myocardial, and skeletal muscle ischaemia and I/R injury and discuss preliminary data that alludes to the potential role of TLRs in the pathophysiology of skeletal muscle damage in CLI.

Dendritic cells (DC) are professional antigen presenting cells that represent an important link between innate and adaptive immunity. Danger signals such as toll-like receptor (TLR) agonists induce maturation of DC leading to a T-cell mediated adaptive immune response. In this study, we show that exogenous as well as endogenous inflammatory stimuli for TLR4 and TLR2 induce the expression of HIF-1alpha in human monocyte-derived DC under normoxic conditions. On the functional level, inhibition of HIF-1alpha using chetomin (CTM), YC-1 and digoxin lead to no consistent effect on MoDC maturation, or cytokine secretion despite having the common effect of blocking HIF-1alpha stabilization or activity through different mechanisms. Stabilization of HIF-1alpha protein by hypoxia or CoCl(2) did not result in maturation of human DC. In addition, we could show that TLR stimulation resulted in an increase of HIF-1alpha controlled VEGF secretion. These results show that stimulation of human MoDC with exogenous as well as endogenous TLR agonists induces the expression of HIF-1alpha in a time-dependent manner. Hypoxia alone does not induce maturation of DC, but is able to augment maturation after TLR ligation. Current evidence suggests that different target genes may be affected by HIF-1alpha under normoxic conditions with physiological roles that differ from those induced by hypoxia.

Endothelin-1 (ET-1) is mainly secreted by endothelial cells and acts as a potent vasoconstrictor. In addition ET-1 has also been shown to have pleiotropic effects on a variety of other systems including adaptive immunity. There are two main ET-1 receptors, ET(A) and ET(B), which have different tissue and functional distributions. Dendritic cells (DC) are pivotal antigen-presenting cells linking the innate with the adaptive immune system. DC are sentinels expressing pattern-recognition receptors, e.g. the toll-like receptors (TLR) for detecting danger signals released from pathogens or tissue injury. Here we show for the first time that stimulation of human monocyte-derived DC with exogenous as well as endogenous selective TLR4 and TLR2 agonists induces the production of ET-1 in a dose- and time-dependent manner. 'Alternative' activation of DC in the presence of 1alpha,25-dihydroxyvitamin D(3) results in a marked potentiation of the endothelin response, whereas prostaglandin E(2) or dexamethasone do not increase ET-1 production. Furthermore, chetomin, an inhibitor of the transcription factor hypoxia-inducible factor 1alpha (HIF-1alpha), prevents TLR-mediated secretion of ET-1. Surprisingly, stimulation of human monocytes with LPS does not lead to secretion of detectable amounts of ET-1. These results suggest a role of ET-1 as an important player in human DC biology and innate immunity in general.

Objective: Conventional harvesting of saphenous vein used for coronary artery bypass surgery induces a vasospasm that is overcome by high-pressure distension. Saphenous vein harvested with its cushion of perivascular tissue by a "no touch" technique does not undergo vasospasm and distension is not required, leading to an improved graft patency. The aim of this study is to investigate the effect of surgical damage and high-pressure distension on endothelial integrity and endothelial nitric oxide synthase expression and activity in saphenous vein harvested with and without perivascular tissue., Methods: Saphenous veins from patients (n = 26) undergoing coronary artery bypass surgery were prepared with and without perivascular tissue. We analyzed the effect of 300 mm Hg distension on morphology and endothelial nitric oxide synthase/nitric oxide synthase activity using a combination of immunohistochemistry, Western blot analysis, reverse transcriptase polymerase chain reaction, and enzyme assay in distended (with and without perivascular tissue) compared with nondistended (with and without perivascular tissue) segments., Results: Distension induced substantial damage to the luminal endothelium (assessed by CD31 staining) and vessel wall. Endothelial nitric oxide synthase expression and activity were significantly reduced by high-pressure distension and removal of, or damage to, perivascular tissue. The effect of distension was significantly less for those with perivascular tissue than for those without perivascular tissue in most cases., Conclusion: The success of the saphenous vein used as a bypass graft is affected by surgical trauma and distension. Veins removed with minimal damage exhibit increased patency rates. We show that retention of perivascular tissue on saphenous vein prepared for coronary artery bypass surgery by the "no touch" technique protects against distension-induced damage, preserves vessel morphology, and maintains endothelial nitric oxide synthase/nitric oxide synthase activity.

Background: Studies were carried out to test the hypothesis that administration of a glucocorticoid Type II receptor antagonist, mifepristone (RU38486), just prior to withdrawal from chronic alcohol treatment, would prevent the consequences of the alcohol consumption and withdrawal in mice., Materials and Methods: The effects of administration of a single intraperitoneal dose of mifepristone were examined on alcohol withdrawal hyperexcitability. Memory deficits during the abstinence phase were measured using repeat exposure to the elevated plus maze, the object recognition test, and the odor habituation/discrimination test. Neurotoxicity in the hippocampus and prefrontal cortex was examined using NeuN staining., Results: Mifepristone reduced, though did not prevent, the behavioral hyperexcitability seen in TO strain mice during the acute phase of alcohol withdrawal (4 hours to 8 hours after cessation of alcohol consumption) following chronic alcohol treatment via liquid diet. There were no alterations in anxiety-related behavior in these mice at 1 week into withdrawal, as measured using the elevated plus maze. However, changes in behavior during a second exposure to the elevated plus maze 1 week later were significantly reduced by the administration of mifepristone prior to withdrawal, indicating a reduction in the memory deficits caused by the chronic alcohol treatment and withdrawal. The object recognition test and the odor habituation and discrimination test were then used to measure memory deficits in more detail, at between 1 and 2 weeks after alcohol withdrawal in C57/BL10 strain mice given alcohol chronically via the drinking fluid. A single dose of mifepristone given at the time of alcohol withdrawal significantly reduced the memory deficits in both tests. NeuN staining showed no evidence of neuronal loss in either prefrontal cortex or hippocampus after withdrawal from chronic alcohol treatment., Conclusions: The results suggest mifepristone may be of value in the treatment of alcoholics to reduce their cognitive deficits.

Effects of the dihydropyridine, nimodipine, an antagonist at L-type calcium channels, on the memory loss in rats caused by long term alcohol consumption were examined. Either a single dose of nimodipine or 2 weeks of repeated administration was given prior to withdrawal from 8 months of alcohol consumption. Memory was measured by the object recognition test and the T maze. Both nimodipine treatments prevented the memory deficits when these were measured between 1 and 2 months after alcohol withdrawal. At the end of the memory testing, 2 months after cessation of chronic alcohol consumption, glucocorticoid concentrations were increased in specific regions of rat brain without changes in plasma concentrations. Both nimodipine treatment schedules substantially reduced these rises in brain glucocorticoid. The data indicate that blockade of L-type calcium channels prior to alcohol withdrawal protects against the memory deficits caused by prolonged alcohol intake. This shows that specific drug treatments, such as nimodipine, given over the acute withdrawal phase, can prevented the neuronal changes responsible for subsequent adverse effects of long term consumption of alcohol. The results also suggest the possibility that regional brain glucocorticoid increases may be involved in the adverse effects of long term alcohol intake on memory. Such local changes in brain glucocorticoid levels would have major effects on neuronal function. The studies indicate that L-type calcium channels and brain glucocorticoid levels could form new targets for the treatment of cognitive deficits in alcoholics.

Concentrations of corticosterone in brain areas of TO strain mice were measured by radioimmunoassay. The studies examined the effects of routine laboratory maneuvers, variation during the circadian peak, adrenalectomy, social defeat and acute injections of alcohol on these concentrations. Brief handling of mice increased corticosterone levels in plasma but not in striatum and reduced those in the hippocampus. Single injections of isotonic saline raised the plasma concentrations to a similar extent as the handling, but markedly elevated concentrations in the three brain regions. Five minutes exposure to a novel environment increased hippocampal and cerebral cortical corticosterone levels and striatal concentrations showed a larger rise. However, by 30 min in the novel environment, plasma concentrations rose further while those in striatum and cerebral cortex fell to control levels and hippocampal corticosterone remained elevated. Over the period of the circadian peak the hippocampal and striatal concentrations paralleled the plasma concentrations but cerebral cortical concentrations showed only small changes. Adrenalectomy reduced plasma corticosterone concentrations to below detectable levels after 48 h but corticosterone levels were only partially reduced in the hippocampus and striatum and remained unchanged in the cerebral cortex. Single or repeated social defeat increased both brain and plasma concentrations after 1 h. Acute injections of alcohol raised the regional brain levels in parallel with plasma concentrations. The results show that measurements of plasma concentrations do not necessarily reflect the levels in brain. The data also demonstrate that corticosterone levels can change differentially in specific brain regions. These results, and the residual hormone seen in the brain after adrenalectomy, are suggestive evidence for a local origin of central corticosterone.

The hypothalamo-pituitary-adrenal axis shows functional changes in alcoholics, with raised glucocorticoid release during alcohol intake and during the initial phase of alcohol withdrawal. Raised glucocorticoid concentrations are known to cause neuronal damage after withdrawal from chronic alcohol consumption and in other conditions. The hypothesis for these studies was that chronic alcohol treatment would have differential effects on corticosterone concentrations in plasma and in brain regions. Effects of chronic alcohol and withdrawal on regional brain corticosterone concentrations were examined using a range of standard chronic alcohol treatments in two strains of mice and in rats. Corticosterone was measured by radioimmunoassay and the identity of the corticosterone extracted from brain was verified by high performance liquid chromatography and mass spectrometry. Withdrawal from long term (3 weeks to 8 months) alcohol consumption induced prolonged increases in glucocorticoid concentrations in specific regions of rodent brain, while plasma concentrations remained unchanged. This effect was seen after alcohol administration via drinking fluid or by liquid diet, in both mice and rats and in both genders. Shorter alcohol treatments did not show the selective effect on brain glucocorticoid levels. During the alcohol consumption the regional brain corticosterone concentrations paralleled the plasma concentrations. Type II glucocorticoid receptor availability in prefrontal cortex was decreased after withdrawal from chronic alcohol consumption and nuclear localization of glucocorticoid receptors was increased, a pattern that would be predicted from enhanced glucocorticoid type II receptor activation. This novel observation of prolonged selective increases in brain glucocorticoid activity could explain important consequences of long term alcohol consumption, including memory loss, dependence and lack of hypothalamo-pituitary responsiveness. Local changes in brain glucocorticoid levels may also need to be considered in the genesis of other mental disorders and could form a potential new therapeutic target.

Background: Dysfunction of the nitric oxide pathway is implicated in peripheral arterial disease. Nitric oxide synthase (NOS) isoforms and NOS activity were studied in muscle from patients with critical leg ischaemia (CLI). Alterations in NOS during revascularization surgery were also assessed., Methods: Muscle biopsies were taken from patients with CLI undergoing amputation and also from patients undergoing femorodistal bypass at the start of surgery, after arterial clamping and following reperfusion. The presence of NOS within muscle sections was confirmed using reduced nicotinamide adenine dinucleotide phosphate diaphorase histochemistry. NOS isoform distribution was studied by immunohistochemistry. NOS mRNA and protein levels were measured using real-time reverse transcriptase-polymerase chain reaction and western blotting. NOS activity was assessed with the citrulline assay., Results: All three NOS isoforms were found in muscle, associated with muscle fibres and microvessels. NOS I and III protein expression was increased in CLI (P = 0.041). During revascularization, further ischaemia and reperfusion led to a rise in NOS III protein levels (P = 0.008). NOS activity was unchanged., Conclusion: Alterations in NOS I and III occurred in muscle from patients with CLI and further changes occurred during bypass surgery., (Copyright (c) 2007 British Journal of Surgery Society Ltd.)

Background: Chronic extrinsic denervation induced by small bowel transplantation (SBT) results in adrenergic hypersensitivity in rat ileum. This study evaluated the role of neuronal and/or muscular beta1-, beta2-, and beta3-adrenoceptor (AR) mechanisms on contractility., Methods: Ileal longitudinal muscle strips from Lewis rats (n = 6 rats per group, 8 strips per rat): naïve controls (NC), 4 months after sham operation (SC) or after syngeneic orthotopic SBT were studied in vitro. Spontaneous contractile activity and dose responses (10(-8)-10(-4) mol) to isoprenaline (IP), a nonspecific beta-AR agonist were studied with or without selective antagonists (10(-5) mol), for beta1- (atenolol), beta2- (ICI 118551), or beta3- (SR 59230A) AR subtypes in the presence or absence of tetrodotoxin (TTX; 10(-6) mol; nerve blocker)., Results: pEC50 (neg log of EC50, which is the concentration where 50% of inhibition was observed) of IP was 7.2 +/- 0.2 (mean value +/- SEM) in SBT vs 6.3 +/- 0.1 in SC and 6.3 +/- 0.2 in NC (both P < .05 vs SBT), reflecting adrenergic hypersensitivity. Beta1- and beta2-AR blockade induced a TTX-sensitive right shift of the curve only in SBT and normalized pEC50 values from 7.2 +/- 0.2 to 6.4 +/- 0.1 and 7.2 +/- 0.2 to 6.6 +/- 0.1, respectively (P < .05). Beta3-AR blockade shifted the curve independent of the presence of TTX to the right in all groups (all P < .05)., Conclusions: In rat ileum, adrenergic inhibition of contractility was dependent on muscular beta3-AR pathways, whereas posttransplant hypersensitivity was due to upregulated neuronal beta1- and beta2-AR mechanisms that were inactive before SBT.

Alterations in nitric oxide synthase (NOS) are implicated in ischemia and ischemia-reperfusion injury. Changes in the 3 NOS isoforms in human skeletal muscle subjected to acute ischemia and reperfusion were studied. Muscle biopsies were taken from patients undergoing total knee replacement. Distribution of the specific NOS isoforms within muscle sections was studied using immunohistochemistry. NOS mRNA levels were measured using real-time reverse transcription-polymerase chain reaction and protein levels studied using Western blotting. NOS activity was also assessed using the citrulline assay. All 3 NOS isoforms were found in muscle sections associated with muscle fibers and microvessels. In muscle subjected to acute ischemia and reperfusion, NOS I/neuronal NOS mRNA and protein were elevated during reperfusion. NOS III/endothelial NOS was also upregulated at the protein level during reperfusion. No changes in NOS II/inducible NOS expression or NOS activity occurred. In conclusion, alterations in NOS I and III (neuronal NOS and endothelial NOS) at different levels occurred after acute ischemia and reperfusion in human skeletal muscle; however, this did not result in increased NOS activity. In the development of therapeutic agents based on manipulation of the NO pathway, targeting the appropriate NOS isoenzymes may be important.

N-acetylcysteine (NAC) is neuroprotective in animal models of acute brain injury such as caused by bacterial meningitis. However, the mechanism(s) by which NAC exerts neuroprotection is unclear. Gene expression of endothelin-1 (ET-1), which contributes to cerebral blood flow decline in acute brain injury, is partially regulated by reactive oxygen species, and thus a potential target of NAC. We therefore examined the effect of NAC on tumor necrosis factor (TNF)-alpha-induced ET-1 production in cerebrovascular endothelial cells. NAC dose dependently inhibited TNF-alpha-induced preproET-1 mRNA upregulation and ET-1 protein secretion, while upregulation of inducible nitric oxide synthase (iNOS) was unaffected. Intriguingly, NAC had no effect on the initial activation (i.e., IkappaB degradation, nuclear p65 translocation, and Ser536 phosphorylation) of NF-kappaB by TNF-alpha. However, transient inhibition of NF-kappaB DNA binding suggested that NAC may inhibit ET-1 upregulation by inhibiting (a) parallel pathway(s) necessary for full transcriptional activation of NF-kappaB-mediated ET-1 gene expression. Similar to NAC, the MEK1/2 inhibitor U0126, the p38 inhibitor SB203580, and the protein kinase inhibitor H-89 selectively inhibited ET-1 upregulation without affecting nuclear p65 translocation, suggesting that NAC inhibits ET-1 upregulation via inhibition of mitogen- and stress-activated protein kinase (MSK). Supporting this notion, cotreatment with NAC inhibited the TNF-alpha-induced rise in MSK1 and MSK2 kinase activity, while siRNA knock-down experiments showed that MSK2 is the predominant isoform involved in TNF-alpha-induced ET-1 upregulation.

Background: The benefit of intravenous recombinant tissue plasminogen activator (rtPA) in acute stroke is linked to clot lysis and artery recanalization. Argatroban is a direct thrombin inhibitor that safely augments the benefit of rtPA in animal stroke models. There are no human data on this combination., Design: We report the first phase of the Argatroban tPA Stroke Study, an ongoing prospective, open-label, dose-escalation, safety and activity study of argatroban and rtPA in patients with ischemic stroke. The primary outcome was incidence of intracerebral hemorrhage; secondary outcome, complete recanalization at 2 hours. After standard-dose intravenous rtPA administration, a 100-mug/kg bolus of argatroban followed by infusion of 1 mug/kg per minute for 48 hours was adjusted to a target partial thromboplastin time of 1.75 times that of the control group., Results: Fifteen patients (including 10 men) were enrolled, with a mean +/- SD age of 61 +/- 13 years. All patients had middle cerebral artery occlusions. Baseline median National Institute of Health Stroke Scale score was 14 (range, 4-25). The mean +/- SD time from symptom onset to argatroban bolus administration was 172 +/- 53 minutes. Symptomatic intracerebral hemorrhage occurred in 2 patients, including 1 with parenchymal hemorrhage type 2. Asymptomatic bleeding occurred in 1 patient and there was 1 death. Recanalization was complete in 6 patients and partial in another 4, and reocclusion occurred in 3 within 2 hours of rtPA bolus administration., Conclusion: The safety of low-dose argatroban combined with intravenous rtPA may be within acceptable limits, and its efficacy for producing fast and complete recanalization is promising, but a larger cohort of patients is required to confirm these preliminary observations.

Although experimental prevention studies have suggested therapeutic potential of endothelin (ET) antagonists for the treatment of heart failure, the results of clinical trials using ET antagonists on top of standard heart failure medications have been largely disappointing. This experimental study investigated the effects of chronic ET(A) receptor blockade in long-term survivors of myocardial infarction who had developed stable chronic heart failure in the absence of other treatments. Systolic blood pressure, heart rate, organ weights of the right atrium and ventricle, and the lungs were determined, and tissue ET-1 peptide levels were measured in cardiac tissue, lung, and aorta. The results show that chronic blockade of ET(A) receptors stabilizes systolic blood pressure and reverses the heart failure-induced weight increases of right heart chambers and lung. The changes observed occurred independently of tissue ET-1 concentrations and heart rate, suggesting mechanisms independent of local cardiac or pulmonary ET-1 synthesis, which are yet to be identified.

Endothelin regulates cytokine expression in vitro and in vivo. This study investigated the effects of chronic allograft rejection on hepatic endothelin-converting enzyme-1 (ECE-1) gene expression and endothelin-1 (ET-1) plasma clearance. Using the Lewis-F344 minor histocompatibility mismatch model of heterotopic cardiac transplantation, hepatic ECE-1 gene expression was measured by real-time polymerase chain reaction and host plasma clearance of ET-1 was measured 8 weeks after transplantation in the absence of immunosuppression. In animals undergoing allograft rejection, hepatic ECE-1 gene expression increased 2-fold (P < 0.05), whereas no effect of rejection on ET-1 clearance from plasma was observed. In summary, upregulation of ECE-1 gene expression occurs in the liver of the host during chronic allograft rejection. Because the liver represents both a key organ for cytokine production and for endothelin metabolism, increased hepatic ECE-1-mediated ET-1 synthesis may contribute to host responses and cytokine production during allograft rejection.

Altered activity of retinal endothelin-1 (ET-1) and nitric oxide may play a causal role in the hemodynamic and histopathological changes of diabetic retinopathy. This study evaluated the therapeutic potential of long-term selective blockade of the ET-1(A) receptor (ETRA) to prevent the development of retinopathy in a genetic mouse model of nonobese type 1 diabetes (NOD). Mice with NOD that received subcutaneous implantation of insulin pellets and wild-type control mice were treated for 4 months with the selective ETRA antagonist LU208075 (30 mg/kg/day) via drinking water. At the end of the study, blood glucose levels were evaluated, and animals were anesthetized and perfused intracardially with FITC-labeled dextran. Retinas were removed and either fixed in formalin for confocal microscope evaluation of retinal vascular filling or transferred to RNALater for quantitative reverse transcriptase-polymerase chain reaction to evaluate expression of NOS-3, NOS-1, ET-1, ETRA, ETRB, and the angiogenic factor adrenomedullin. Compared with wild-type controls, expression of ET-1, ETRA, ETRB, and adrenomedullin in mice with NOD were markedly upregulated in the retinas of nontreated mice (cycle time values relative to GAPDH [deltaCt], 14.8 vs. 13.7, 18.57 vs. 17.5, 10.76 vs. 9.9, and 11.7 vs. 9.1, respectively). Mean integral fluorescence intensity (MIFI) of retinal vascular filling was reduced from normal values of 24 to 12.5 in nontreated animals. LU208075 treatment normalized the upregulated expression of ET-1 and adrenomedullin, as well as the deficit in MIFI, but did not affect the increased ETRA and ETRB expression or the elevated plasma glucose levels found in nontreated animals. NOS isoform expression was essentially unchanged. ETRA antagonists may provide a novel therapeutic strategy to slow or prevent progression of retinal microvascular damage and proliferation in patients for whom there is clear evidence of activation of the ET-1 system.

There is increasing evidence to suggest that chronic activation of the endothelin-1 system can lead to heterologous desensitization of the glucose-regulatory and mitogenic actions of insulin with subsequent development of glucose intolerance, hyperinsulinemia, impaired endothelial function and exacerbation of cardiovascular disease. Effects are mediated through a variety of mechanisms that include attenuation of key insulin signalling pathways and decreased tyrosine phosphorylation of insulin receptor substrates IRS-1, SHC and G alpha q/11. Other actions involve hemodynamic changes leading to reduced delivery of insulin and glucose to peripheral tissues as well as enhanced hepatic glycogenolysis, decreased glucose-transporter translocation and modulation of various adipokines that regulate insulin action. Overall the data suggest that ET-1 antagonists may provide an effective means of improving cardiac dysfunction and favourably influencing glucose tolerance in obese humans and patients with early insulin sensitivity where there is clear evidence for activation of the ET-1 system. Although most effects of ET-1 that modulate mechanisms leading to glucose intolerance appear to involve the ETA receptor subtype recent data indicates that combined ETA/ETB receptor antagonists may function as effectively as selective ETA blockers. Prospective trials are needed to assess whether ET-1 antagonists, either alone or in combination, are superior to other more conventional therapies such as insulin sensitizers and to evaluate effects of combined treatments on the development of insulin resistance and the progression of diabetes. Early screening of patients at risk for evidence of ET-1 activation would help to identify subjects who may benefit most from such treatment.

Background/aims: It is postulated that nitric oxide (NO) is responsible for the hyperdynamic circulation of portal hypertension. Therefore, we investigated induction of fibrosis and hyperdynamic circulation in endothelial NO synthase knock-out (KO) mice., Methods: Fibrosis was induced by bile duct ligation. Hemodynamic studies were performed after portal vein ligation. All studies were performed in wild-type (WT) and KO mice., Results: Three to 4 weeks after bile duct ligation (BDL), both WT and KO groups had similar degrees of portal hypertension, 12 (9-14) and 11(8-15) mmHg, median (range), and liver function. Fibrosis increased from 0.0% in sham operated to 1.0 and 1.1% in WT and KO mice, respectively. Cardiac output was similar after portal vein ligation (20 and 17 ml/min in WT and KO mice, respectively). There was no difference in liver of mRNA for endothelin 1, inducible NO synthase (iNOS) and hem-oxygenase 1 (HO1); proteins of iNOS, HO1 and HO2; nor in endothelin A and B (EtA and EtB) receptor density between WT and KO mice after BDL., Conclusions: These results suggest that endothelial NO synthase is neither essential for the development of fibrosis and portal hypertension in bile duct ligated mice, nor for the hyperdynamic circulation associated with portal hypertension in the portal vein ligated mice.

Aim: To compare the plasma levels of endothelin-1 (ET-1) between patients with primary open angle glaucoma with visual field progression despite normal or normalised intraocular pressure and patients with stabile visual fields in a retrospective study., Methods: The progressive group consisted of 16 primary open angle glaucoma patients and the group with stable visual field consisted of 15 patients. After a 30 minute rest in a supine position, venous blood was obtained for ET-1 dosing. Difference in the plasma level of ET-1 between two groups was compared by means of analysis of covariance (ANCOVA), including age, sex, and mean arterial blood pressure as covariates., Results: ET-1 plasma levels were found to be significantly increased in patients with deteriorating (3.47 (SD 0.75) pg/ml) glaucoma when compared to those with stable (2.59 (SD 0.54) pg/ml) visual fields (p = 0.0007)., Conclusions: Glaucoma patients with visual field progression in spite of normal or normalised intraocular pressure have been found to have increased plasma endothelin-1 levels. It remains to be determined if this is a secondary phenomenon or whether it may have a role in the progression of glaucomatous damage.

Background: In recent years, the assessment of the plasma aldosterone-to-renin ratio (ARR) has become an established screening method for the diagnosis of primary aldosteronism. Plasma renin activity (PRA) is usually measured to define ARR although, increasingly, renin concentration alone is often measured in clinical routine., Objective: To determine the threshold of ARR using active renin concentration to screen for primary aldosteronism., Design and Participants: To determine the ARR threshold based on plasma immunoreactive renin concentration (irR), we measured plasma aldosterone concentration (PAC), irR and PRA in 36 hypertensive patients, nine thereof with adrenal adenoma, and compared ARRs calculated from irR and PRA, respectively., Setting: Single-centre, hypertension clinic in a tertiary care hospital., Results: PRA ranged from 0.41-14.9 ng/ml per h and irR from 1.1-72 ng/l. There was an excellent correlation between PRA and irR (r = 0.98, P < 0.0001) and between ARRPRA and ARRirR (r = 0.96, P < 0.0001). An ARRPRA > 750 pmol/l per ng/ml per h was previously found to be highly predictive of primary aldosteronism because 90% of the corresponding patients failed to suppress PAC upon saline infusion or fludrocortisone. The corresponding threshold value for ARRirR was 150 pmol/ng in our patients. Using these cut-offs, nine subjects had both increased ARRPRA and ARRirR while, in three patients, either ARRPRA or ARRirR were increased. The nine patients with increased ARRPRA and ARRirR also had PAC > 650 pmol/l. Only these patients had adrenal adenomas., Conclusions: The ARR threshold to screen for primary aldosteronism may be based on measurement of irR. An ARRirR > 150 pmol/ng may indicate primary aldosteronism.

Purpose: To analyze how far an ischemic component might have been involved in optic neuritis., Case Report: a 32-year-old man with symptoms characteristic for optic neuritis underwent extensive clinical, laboratory/serological and vascular examination for systemic associations and vascular involvement., Results: The patient was found to have a temporary ocular blood flow dysregulation and increased plasma endothelin-1 levels which decreased after the acute phase of the optic nerve., Conclusions: We conclude that there might be an ischemic component in this patient with optic neuritis and hypothesize that this ischemic component is at least in part due to a temporarily increased endothelin-1 level., (Copyright 2003 S. Karger AG, Basel)

Secondary complications of diabetes mellitus often involve gastrointestinal dysfunction. In the experimental Goto Kakizaki rat, a model of Type II diabetes, hyperglycaemia and reduced glucose clearance is associated with elevated plasma endothelin (ET)-1 levels and selective decreases in nitric oxide synthase in circular muscle, longitudinal muscle and neuronal elements of the gastrointestinal tract. Functionally, this is accompanied by decreased nitrergic relaxatory responses of jejunal longitudinal muscle to tetrodotoxin-sensitive electrical field stimulation. Long-term treatment with a selective ET A-type receptor antagonist, markedly reduced hyperglycaemia and restored plasma glucose clearance rates towards normal. This was associated with a restoration of N(G)-nitro-L-arginine methyl ester-sensitive relaxatory responses of jejunal longitudinal muscle to electrical field stimulation. The results indicate that beneficial effects of ETA receptor blockade on gastrointestinal function may result from an improvement in insulin sensitivity with concomitant reduction of the severity of hyperglycaemia. ETA receptor blockade may represent a new therapeutic principle for improving glucose tolerance in Type II diabetes and could be beneficial in alleviating or preventing hyperglycaemia-related secondary complications in this condition.

A 3-month-old, full-term female infant was hospitalized with pneumonia and bronchiolitis. Laboratory studies revealed a profoundly low level of IgG (41 mg/dL) and low level of IgA (< 6.67 mg/dL). Other causes of immunodeficiency were ruled out, and there was no evidence of protein loss to account for the low immunoglobulin levels. The immunoglobulin levels normalized over time. Our patient had a transient hypogammaglobulinemia of infancy, with severely low IgG and low IgA levels. We found no other reports of cases with such low values of IgG that proved to be transient.

Background: The enzyme 11beta-hydroxysteroid dehydrogenase (11beta-HSD) prevents inappropriate activation of the nonselective mineralocorticoid receptors by glucocorticoids. Renal activity of 11beta-HSD is decreased in patients with apparent mineralocorticoid excess (SAME), licorice-induced hypertension, and essential hypertension. Although expressed in vascular cells, the role of 11beta-HSD in the regulation of vascular tone remains to be determined., Methods and Results: lycyrrhizic acid (GA; 50 mg/kg IP, twice daily for 7 days) caused a significant inhibition of 11beta-HSD activity and induced hypertension in Wistar-Kyoto rats (157 versus 127 mm Hg in controls; P<0.01). After 11beta-HSD inhibition, aortic endothelial nitric oxide (NO) synthase (eNOS) protein content, nitrate tissue levels, and acetylcholine-induced release of NO were blunted (all P<0.05 versus controls). In contrast, vascular prepro-endothelin (ET)-1 gene expression, ET-1 protein levels, and vascular reactivity to ET-1 were enhanced by GA treatment (P<0.05 versus controls). Chronic ET(A) receptor blockade with LU135252 (50 mg. kg(-1). d(-1)) normalized blood pressure, ET-1 tissue content, vascular reactivity to ET-1, vascular eNOS protein content, and nitrate tissue levels and improved NO-mediated endothelial function in GA-treated rats (P<0.05 to 0.01 versus untreated and verapamil-treated controls). In human endothelial cells, GA increased production of ET-1 in the presence of corticosterone, which indicates that activation of the vascular ET-1 system by 11beta-HSD inhibition can occur independently of changes in blood pressure but is dependent on the presence of glucocorticoids., Conclusions: Chronic ET(A) receptor blockade normalizes blood pressure, prevents upregulation of vascular ET-1, and improves endothelial dysfunction in 11beta-HSD inhibitor-induced hypertension and may emerge as a novel therapeutic approach in cardiovascular disease associated with reduced 11beta-HSD activity.

Objective: To perform an observational study of the demographics, clinical factors, and therapeutic efficacy in patients presenting to the emergency department with a chief complaint of headache., Background: Acute headache presentations to the emergency department are a therapeutic dilemma for physicians., Methods: Patients presenting with nontraumatic headache to the emergency department of Hermann Hospital in Houston, Texas, during a 16-month period were prospectively ascertained by active and passive surveillance. The medical record was abstracted. Demographic and clinical information are presented with descriptive statistics. Relative benefit of individual therapies are compared with odds ratios (95% confidence intervals)., Results: Of the 38 730 patients who were prospectively screened, 455 presented with a chief complaint of headache. Seventy-six percent were women, and the mean age was 37 years. Non-Hispanic whites were more likely diagnosed with migraine compared with Hispanics or African Americans (P<.001). Three percent had subarachnoid hemorrhage. Neurologist follow-up was ordered in 10%. The median time in the emergency department was 265 minutes. With the initial treatment, 44% resolved, 47% improved, and 9% had no change; none worsened. In comparison with all other therapies used, there was a trend suggesting the superiority of antiemetics (odds ratio, 2.66; 95% confidence interval, 0.81 to 8.61). Acetaminophen was less helpful (odds ratio, 0.27; 95% confidence interval, 0.10 to 0.70). When comparing specific agents to therapies which could be used at home, antiemetics led to headache resolution most often (odds ratio, 3.18; 95% confidence interval, 1.40 to 7.22); ketorolac showed a similar trend (odds ratio, 2.05; 95% confidence interval, 0.86 to 4.89)., Conclusions: Headache in the emergency department is a phenomena of young women who spend a long time waiting and receive many tests. A variety of therapies are used. Antiemetics may be especially useful for headache resolution.

Objective: We tested the hypothesis that the plasma level of endothelin-1 (ET-1) is increased in patients with multiple sclerosis (MS). The peptide ET-1 is one of the most potent known vasoconstrictors. An increased level of endothelin could explain some of the vascular symptoms of these patients., Materials and Methods: A specific radioimmunoassay was used to determine ET-1 plasma levels. Twenty patients with MS were compared to 20 age- and sex-pair-matched healthy subjects., Results: The plasma ET-1 levels were, on average, 224% higher in the patients with MS than in the controls (p < 0.005). The mean ET-1 levels (mean +/- standard deviation [SD]) were 3.5 +/- 0.83 pg/mL (min 2.13, max 5.37 pg/mL) in patients with MS and 1.56 +/- 0.3 pg/mL (min 0.9, max 2.13 pg/mL) in healthy volunteers. Neither the different forms nor stages of MS had an influence on the results. The ET-1 level was also not correlated with the duration of the disease., Conclusions: The plasma ET-1 level is markedly and significantly increased in patients with MS. Neither the cause of such an increase nor the pathogenetic role is known.

Unlabelled: Distracting painful injuries (DPIs) may mask symptoms of spinal injury in blunt trauma victims and form an important element in a decision instrument used to identify individuals who require cervical spine radiography., Objective: To identify the types and frequencies of injuries that actually act as DPIs among blunt trauma patients undergoing cervical spinal radiography., Methods: This was a prospective observational study of consecutive blunt trauma victims presenting to an urban Level 1 regional trauma center between April 1, 1998, and September 30, 1998. Prior to cervical spinal radiography, treating physicians evaluated each patient to determine whether a DPI was present or absent and, if present, what type of injury was sustained. Injuries were categorized as fractures, soft-tissue injuries and lacerations, burns, visceral injuries, crush injuries, or other injuries., Results: Data were collected for 778 patients, between 1 month and 98 years old, of whom 264 (34%) were considered to have DPIs. Physicians were unable to determine the DPI status in 47 (6%) additional cases. Fractures accounted for a majority of DPIs (154, or 58%), 42 (16%) were soft-tissue injuries or lacerations, and 86 (34%) were due to a variety of other entities, including visceral, crush, burn, or other miscellaneous injuries. Among the 37 (5%) patients with an acute cervical spinal injury, 20 (54%) had a DPI, including three (8%) who had DPI as the only indication for cervical radiography., Conclusions: A significant number of blunt trauma patients are believed by clinicians to have DPIs that can possibly mask the presence of cervical spinal injury. Fractures and trauma to soft tissues are the most common types of DPI.

Objective: Reperfusion injury may affect the cardiac NO and endothelin production. We investigated whether 20 min of total ischemia followed by 40 min of reperfusion can induce apoptosis in a Langendorff model of retrogradely perfused rat hearts (37 degrees C; paced at 300/'), and we attempted to correlate these findings with measured tissue NO and ET-1 levels., Methods: An apoptosis detection system was utilized which catalytically incorporates fluorescein-12-dUTP at the 3'-OH DNA ends using the principle of the TUNEL assay, with direct visualization of the labeled DNA. ET-1 was measured by radioimmunoassay and NO3/NO2 by ion pairing HPLC on C18 reverse phase columns., Results: None of the postischemic (n = 6) nor of the control perfused (90 min, n = 6) hearts showed signs of apoptosis, while those exposed to longer ischemia (40 min) and reperfusion (2 h) confirmed the presence of apoptotic cells. Myocardial ET-1 concentrations were 4.8 +/- 1.0 versus 8.3 +/- 2.5 pg/100 mg (control vs. ischemic hearts, respectively; mean +/- SD; p < 0.05). Myocardial NO contents showed no differences., Conclusion: These data suggest that the time window of apoptosis with detectable DNA fragmentation exceeds 20 min of global total ischemia and 40 min of reperfusion, a model frequently used for inducing myocardial stunning. While NO was not increased in postischemic hearts, increased ET-1 levels indirectly argue for a role of ET-1 as inducer of apoptosis, but only at a later stage of reperfusion.

The possible diagnostic or prognostic significance of changes in circulating level of endothelins in a variety of pathological conditions is currently of interest. Unfortunately, no consensus regarding optimization of sensitivity and extraction procedures for the reliable radioimmunoassay of endothelin-1 (ET-1), big endothelin-1 (BigET-1), and endothelin-3 (ET-3) currently exists. The object of the present study was to evaluate aspects of currently used extraction and assay procedures that limit accurate determination of ET in human plasma and define criteria to reduce variability. Critical parameters include the selectivity of commercial antibodies and the ability to remove interfering material after Sep-Pak absorption by selective washing with 24% ethanol in 4% acetic acid or methylene chloride in 0.1% trifluoroacetic acid. Assay sensitivity and specificity in the physiological range is improved by optimizing total binding parameters for the antibodies to give approximately 15-20% binding of radiolabeled peptide. With these modifications normal plasma values for ET-1, BigET-1, and ET-3 averaged 1.7 +/- 0.06, 2.5 +/- 0.3, and 5.8 +/- 0.2 pg/ml, respectively. These data suggest that such modifications may help to resolve many of the earlier difficulties concerning the role of ET under normal and pathological conditions., (Copyright 2000 Academic Press.)

Syndrome X may be caused by a coronary microvascular dysfunction, possibly due to abnormalities in coronary endothelial function. Previous studies suggested that endothelin-1 (ET-1) might be involved in the pathogenesis of syndrome X. Baseline arterial and coronary sinus ET-1 levels were measured in 13 patients with syndrome X (10 women, 52+/-7 years) and in 8 control patients (5 women, 46+/-11 years). ET-1 was also measured after atrial pacing in 12 patients with syndrome X and all controls. To simultaneously assess the activity of nitric oxide, guanosine 3'-5'-cyclic monophosphate (cGMP) was also measured in 11 patients with syndrome X and 7 controls. Baseline arterial (2.27+/-0.46 vs. 1.90+/-0.22 pg/ml, p<0.05) and coronary sinus (2.03+/-0.43 vs. 1.68+/-0.28 pg/ml, p = 0.06) ET-1 plasma levels were higher in patients than in controls. After pacing, arterial ET-1 levels did not change in either group and coronary sinus ET-1 levels were also unchanged in controls. In contrast, coronary sinus ET-increased significantly in response to atrial pacing in patients with syndrome X (p = 0.023), and differences between coronary sinus ET-1 levels of patients with syndrome X and controls after pacing became highly significant (2.22+/-0.45 vs. 1.69+/-0.20 pg/ml, respectively, p = 0.006). No significant differences in arterial and coronary sinus cGMP concentrations were found between the 2 groups, both at baseline and after pacing. Our findings suggest that an increased vasoconstrictor activity of microvascular endothelium is present in at least some patients with syndrome X and may be involved in the pathogenesis of the syndrome.

The generation and activity of NK cells appear to be regulated by a particular set of cytokines. We examined the in vivo effects of recombinant human Flt3 ligand (Flt3-L), a recently cloned potent hemopoietic cytokine, on NK cell development in mice. Daily i.p. administration of Flt3-L consistently induced striking increases in both the absolute number and the total cytotoxic activity of mature nonactivated NK cells within various tissues. Dose- and time-dependent increases were observed in the bone marrow (approximately 2- and approximately 11-fold, respectively), thymus (approximately 2.8- and approximately 2.0-fold), blood (approximately 11- and approximately 15-fold), spleen (approximately 10- and approximately 9-fold), and liver (approximately 15- and approximately 39-fold). In addition, IL-2 induced a rapid increase in NK activity, NK cell proliferative responses, generation of lymphokine-activated killer activity, and development of activated adherent NK cells, which were all significantly increased by Flt3-L treatment. Thus, in addition to its recently reported capacity to stimulate dendritic cell production, Flt3-L has a prominent biologic role in NK cell generation in vivo. This is probably a result of selectively induced expansion of NK cell progenitors (pro-NK cells), because Flt3-L stimulates in vitro proliferation of pro-NK cells without affecting the cytotoxicity of mature NK cells. The results also indicate that either alone or in combination with a potent activator of NK cells, such as IL-2, Flt3-L could be used to markedly augment the number and activity of NK cells, especially in the liver. Flt3-L appears to have considerable potential for therapy of both cancer and viral infection.

Study Objective: This study investigated the hypothesis that modern computed tomographic (CT) imaging is sufficient to exclude subarachnoid hemorrhage (SAH) in patients with severe headache., Methods: All 38,730 adult patients who presented to Hermann Hospital in Houston, Texas, during a 16-month period were prospectively screened to detect those with "the worst headache of my life." Two neuroradiologists blinded to the study hypothesis interpreted the CT scans. Patients with negative scans underwent comprehensive cerebrospinal fluid (CSF) analysis including cell count in first and last tubes, visual and spectrophotometric detection of xanthochromia, and CSF D-dimer assay., Results: A chief complaint of headache was elicited in 455 patients, and 107 of these had "worst headache" and were enrolled in the study. CT-confirmed SAH was found in 18 of the 107 (17%). Only 2 patients (2.5%, 95% confidence interval, .3% to 8.8%) had SAH detected by CSF analysis among those with negative CT imaging result. CSF spectrophotometric detection was the most sensitive test for blood. Three patients with less than 6 red blood cells in tube 1 had positive spectrophotometric results, but in all 3, tube 4 was negative on spectrophotometric analysis, suggesting a high false-positive rate., Conclusion: Modern CT imaging is sufficient to exclude 97.5% of SAH in patients presenting to the ED with "worst headache" symptoms.

Humans genetically predisposed to hypertension tend to develop at a prehypertensive stage subtle metabolic and hormonal dysregulations, and certain of these could potentially be angiotensin II dependent. Therefore the aim of this study was to investigate the effects of the angiotensin II-receptor antagonist losartan on insulin sensitivity, lipid profile, and plasma endothelin-1 (ET-1) levels in normotensive offspring of hypertensive parents with a randomized, double-blind, placebo- controlled, crossover design. Insulin sensitivity index (SI), determined by the Minimal Model Method of Bergman, fasting plasma insulin and glucose concentrations, serum total and HDL cholesterol, serum triglycerides, and plasma ET-1 levels were assessed in 19 young (26.2 +/- 0.7 years, mean +/- SEM), healthy, lean [body mass index (BMI), 22.6 +/- 0.7 kg/m2] normotensive male offspring of essential hypertensive parents after 14 days of losartan, 50 mg, and 14 days of placebo, respectively. Compared with placebo, losartan administration did not significantly modify SI (12.2 +/- 1.7 vs. 12.7 +/- 1.5 x 10(-4)/min/microU/ml on placebo), fasting plasma insulin and glucose, as well as the areas under the insulin and glucose curves. Plasma ET-1 levels also did not differ significantly between the placebo and losartan administration phases (1.1 +/- 0.06 vs. 1.2 +/- 0.06 pg/ml). However, serum total cholesterol and triglycerides decreased significantly with losartan treatment (3.8 +/- 0.2 vs. 4.1 +/- 0.2 mM and 0.9 +/- 0.1 vs. 1.1 +/- 0.1 mM, respectively; p < 0.01). Body weight, BMI, heart rate (HR), blood pressure (BP), and 24-h urinary sodium, potassium, and creatinine values were stable throughout the study. These findings demonstrate that angiotensin II-receptor blockade with losartan, administered in the therapeutic dose of 50 mg daily, does not alter insulin sensitivity determined by the Minimal Model Method of Bergman and does not affect ET-1 in normotensive offspring of essential hypertensive parents. The normal insulin sensitivity in the subjects studied might explain why losartan did not improve it. However, losartan significantly reduced serum total cholesterol and total triglyceride levels.

To investigate the effects of antihypertensive treatment with the angiotensin-converting enzyme (ACE) inhibitor lisinopril on insulin sensitivity and related metabolic variables, the insulin sensitivity index (SI), determined with the Minimal Model Method of Bergman, fasting plasma insulin and glucose concentrations, serum total triglyceride and lipoprotein cholesterol fractions, and blood pressure were assessed in 24 lean, non-diabetic patients with essential hypertension. Following a double-blind, randomised crossover design, these parameters were measured after a 4-week run-in period, after 8 weeks of lisinopril or placebo, and after an additional 8 weeks on placebo or lisinopril, respectively. Furthermore, the level of physical fitness was estimated using the Conconi bicycle ergometer test. SI was low in this study population (5.6 vs 13.3 x 10(-4).min-1.mU-1.l-1 in normal lean control subjects). It did not differ between the placebo run-in phase, the lisinopril phase, and the placebo crossover phase (5.8, 5.5, and 5.4 x 10(-4).min-1.mU-1.l-1, respectively). Moreover, during the administration of lisinopril, no significant changes occurred in fasting plasma insulin and glucose, areas under the glucose and insulin curves, glucose disappearance rate, serum total triglycerides, and cholesterol or lipoprotein cholesterol fractions. Heart rate at rest, body weight, and anaerobic threshold remained stable throughout the study. Compliance assessed by pill-counting exceeded 90% at all visits. These findings demonstrate that the ACE inhibitor lisinopril is neutral with regard to insulin sensitivity, plasma insulin and glucose, and lipoprotein metabolism in patients with essential hypertension.