AVONET: morphological, ecological and geographical data for all birds.

Functional traits offer a rich quantitative framework for developing and testing theories in evolutionary biology, ecology and ecosystem science. However, the potential of functional traits to drive theoretical advances and refine models of global change can only be fully realised when species-level information is complete. Here we present the AVONET dataset containing comprehensive functional trait data for all birds, including six ecological variables, 11 continuous morphological traits, and information on range size and location. Raw morphological measurements are presented from 90,020 individuals of 11,009 extant bird species sampled from 181 countries. These data are also summarised as species averages in three taxonomic formats, allowing integration with a global phylogeny, geographical range maps, IUCN Red List data and the eBird citizen science database. The AVONET dataset provides the most detailed picture of continuous trait variation for any major radiation of organisms, offering a global template for testing hypotheses and exploring the evolutionary origins, structure and functioning of biodiversity.

Role of ghrelin isoforms in the mitigation of hepatic inflammation, mitochondrial dysfunction, and endoplasmic reticulum stress after bariatric surgery in rats.

BACKGROUND/OBJECTIVES: Bariatric surgery improves nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH), but the underlying mechanisms remain elusive. We evaluated the potential role of ghrelin isoforms in the amelioration of hepatic inflammation after sleeve gastrectomy and Roux-en-Y gastric bypass (RYGB). SUBJECTS/METHODS: Plasma ghrelin isoforms were measured in male Wistar rats (n = 129) subjected to surgical (sham operation, sleeve gastrectomy, or RYGB) or dietary interventions [fed ad libitum a normal (ND) or a high-fat diet (HFD) or pair-fed diet]. The effect of acylated and desacyl ghrelin on markers of inflammation, mitochondrial dysfunction, and endoplasmic reticulum (ER) stress in primary rat hepatocytes under palmitate-induced lipotoxic conditions was assessed. RESULTS: Plasma desacyl ghrelin was decreased after sleeve gastrectomy and RYGB, whereas the acylated/desacyl ghrelin ratio was augmented. Both surgeries diminished obesity-associated hepatic steatosis, CD68+- and apoptotic cells, proinflammatory JNK activation, and Crp, Tnf, and Il6 transcripts. Moreover, a postsurgical amelioration in the mitochondrial DNA content, oxidative phosphorylation (OXPHOS) complexes I and II, and ER stress markers was observed. Specifically, following bariatric surgery GRP78, spliced XBP-1, ATF4, and CHOP levels were reduced, as were phosphorylated eIF2α. Interestingly, acylated and desacyl ghrelin inhibited steatosis and inflammation of palmitate-treated hepatocytes in parallel to an upregulation of OXPHOS complexes II, III, and V, and a downregulation of ER stress transducers IRE1α, PERK, ATF6, their downstream effectors, ATF4 and CHOP, as well as chaperone GRP78. CONCLUSIONS: Our data suggest that the increased relative acylated ghrelin levels after bariatric surgery might contribute to mitigate obesity-associated hepatic inflammation, mitochondrial dysfunction, and ER stress.

Dissociation of body mass index, excess weight loss and body fat percentage trajectories after 3 years of gastric bypass: relationship with metabolic outcomes.

BACKGROUND/OBJECTIVES: Body weight, body mass index (BMI) and excess weight loss (EWL) are the most frequently used measures to analyse bariatric surgery outcomes. However, these measurements do not provide accurate information on body composition (BC) with body fat (BF), importantly determining the levels of cardiometabolic risk factors. Our aim was to analyse the evolution of BC after Roux-en-Y Gastric Bypass (RYGB) and its influence on the changes of cardiometabolic risk factors in comparison to BMI and EWL. SUBJECTS/METHODS: A group of 81 obese Caucasian patients (19 males/62 females) aged 44.9±1.3 years undergoing RYGB between January 2006 and December 2011 was prospectively followed up for a period of 3 years. BC was determined by air-displacement plethysmography. Visceral adiposity, physical activity and cardiometabolic risk factors were measured. RESULTS: BF was markedly (P<0.001) reduced after the first year, increasing progressively during the second and third years after RYGB, following a different trajectory than body weight, BMI and EWL that decreased up to the second year post surgery. Markers of glucose homeostasis decreased during the first month and continued to decrease during the first year (P<0.05), remaining stabilised or slightly increased between the second and third years following RYGB. However, markers of lipid metabolism decreased (P<0.05) markedly during the first 12 months, increasing thereafter in parallel to the changes observed in BC, with the exception of high-density lipoprotein-cholesterol, which increased progressively throughout the whole period analysed. CONCLUSIONS: The adverse switch in the changes in BC between the first and the second years after RYGB may underlie the changes observed in cardiometabolic risk factors. Tracking of adiposity during the follow-up of bariatric/metabolic surgery yields clinically relevant information to better identify patients in need of increased lifestyle advice or treatment intensification.

Role of aquaporin-7 in ghrelin- and GLP-1-induced improvement of pancreatic ß-cell function after sleeve gastrectomy in obese rats.

BACKGROUND/OBJECTIVES: Glycerol is a key metabolite for lipid accumulation in insulin-sensitive tissues as well as for pancreatic insulin secretion. We examined the role of aquaporin-7 (AQP7), the main glycerol channel in ß-cells, and AQP12, an aquaporin related to pancreatic damage, in the improvement of pancreatic function and steatosis after sleeve gastrectomy in diet-induced obese rats. SUBJECTS/METHODS: Male Wistar obese rats (n=125) were subjected to surgical (sham operation and sleeve gastrectomy) or dietary (pair-fed to the amount of food eaten by sleeve-gastrectomized animals) interventions. The tissue distribution and expression of AQPs in the rat pancreas were analyzed by real-time PCR, western blotting and immunohistochemistry. The effect of ghrelin isoforms and glucagon-like peptide 1 (GLP-1) on insulin secretion, triacylglycerol (TG) accumulation and AQP expression was determined in vitro in RIN-m5F ß-cells. RESULTS: Sleeve gastrectomy reduced pancreatic ß-cell apoptosis, steatosis and insulin secretion. Lower ghrelin and higher GLP-1 concentrations were also found after bariatric surgery. Acylated and desacyl ghrelin increased TG content, whereas GLP-1 increased insulin release in RIN-m5F ß-cells. Sleeve gastrectomy was associated with an upregulation of AQP7 together with a normalization of the increased AQP12 levels in the rat pancreas. Interestingly, ghrelin and GLP-1 repressed AQP7 and AQP12 expression in RIN-m5F ß-cells. AQP7 protein was negatively correlated with intracellular lipid accumulation in acylated ghrelin-treated cells and with insulin release in GLP-1-stimulated ß-cells. CONCLUSIONS: AQP7 upregulation in ß-cells after sleeve gastrectomy contributes, in part, to the improvement of pancreatic steatosis and insulin secretion by increasing intracellular glycerol used for insulin release triggered by GLP-1 rather than for ghrelin-induced TG biosynthesis.

Guanylin and uroguanylin stimulate lipolysis in human visceral adipocytes.

BACKGROUND/OBJECTIVES: Uroguanylin and guanylin are secreted by intestinal epithelial cells as prohormones postprandially and act on the hypothalamus to induce satiety. The impact of obesity and obesity-associated type 2 diabetes (T2D) on proguanylin and prouroguanylin expression/secretion as well as the potential role of guanylin and uroguanylin in the control of lipolysis in humans was evaluated. SUBJECTS/METHODS: Circulating and gastrointestinal expression of proguanylin (GUCA2A) and prouroguanylin (GUCA2B) were measured in 134 subjects. In addition, plasma proguanylin and prouroguanylin were measured before and after weight loss achieved either by Roux-en-Y gastric bypass (RYGB) (n=24) or after a conventional diet (n=15). The effect of guanylin and uroguanylin (1-100 nmol l(-1)) on lipolysis was determined in vitro in omental adipocytes. RESULTS: Circulating concentrations of prouroguanylin, but not proguanylin, were decreased in obesity in relation to adiposity. Weight loss achieved by RYGB increased plasma proguanylin and prouroguanylin. Obese T2D individuals showed higher expression of intestinal GUCA2A as well as of the receptors of the guanylin system, GUCY2C and GUCY2D, in omental adipocytes. The incubation with guanylin and uroguanylin significantly stimulated lipolysis in differentiated omental adipocytes, as evidenced by hormone-sensitive lipase phosphorylation at Ser563, an increase in fatty acids and glycerol release together with an upregulation of several lipolysis-related genes, including AQP3, AQP7, FATP1 or CD36. CONCLUSIONS: Both guanylin and uroguanylin trigger lipolysis in human visceral adipocytes. Given the lipolytic action of the guanylin system on visceral adipocytes, the herein reported decrease of circulating prouroguanylin concentrations in obese patients may have a role in excessive fat accumulation in obesity.

Reduced hepatic aquaporin-9 and glycerol permeability are related to insulin resistance in non-alcoholic fatty liver disease.

BACKGROUND/OBJECTIVES: Glycerol represents an important metabolite for the control of lipid accumulation and hepatic gluconeogenesis. We investigated whether hepatic expression and functionality of aquaporin-9 (AQP9), a channel mediating glycerol influx into hepatocytes, is impaired in non-alcoholic fatty liver disease (NAFLD) and steatohepatitis (NASH) in the context of insulin resistance. SUBJECTS/METHODS: Liver biopsies were obtained from 66 morbid obese patients undergoing bariatric surgery (66% women, mean body mass index (BMI) 46.1±1.0 kg m(-2)) with available liver echography and pathology analysis of the biopsies in this cross-sectional study. Subjects were classified according to normoglycemia (NG), impaired glucose tolerance (IGT) or type 2 diabetes (T2D). Hepatic expression of AQP9 was analyzed by real-time PCR, western blotting and immunohistochemistry, while glycerol permeability (P(gly)) was measured by stopped-flow light scattering. RESULTS: AQP9 was the most abundantly (P<0.0001) expressed aquaglyceroporin in human liver (AQP9>>>AQP3>AQP7>AQP10). Obese patients with T2D showed increased plasma glycerol as well as lower P(gly) and hepatic AQP9 expression. The prevalence of NAFLD and NASH in T2D patients was 100 and 65%, respectively. Interestingly, AQP9 expression was decreased in patients with NAFLD and NASH as compared with those without hepatosteatosis, in direct relation to the degree of steatosis and lobular inflammation, being further reduced in insulin-resistant individuals. The association of AQP9 with insulin sensitivity was independent of BMI and age. Consistent with these data, fasting insulin and C-reactive protein contributed independently to 33.1% of the hepatic AQP9 mRNA expression variance after controlling for the effects of age and BMI. CONCLUSIONS: AQP9 downregulation together with the subsequent reduction in hepatic glycerol permeability in insulin-resistant states emerges as a compensatory mechanism whereby the liver counteracts further triacylglycerol accumulation within its parenchyma as well as reduces hepatic gluconeogenesis in patients with NAFLD.

The usefulness of plasma histamine and different tryptase cut-off points in the diagnosis of peranaesthetic hypersensitivity reactions.

UNLABELLED: Anaesthetic hypersensitivity reactions can be IgE- or not IgE-mediated and are a challenge to find the causal agent. Histamine and tryptase determination are classically considered useful in the diagnosis of these reactions. The aim of our study was to assess the diagnostic usefulness of plasma histamine and different cut-off points of serum tryptase. METHODS: Patients suffering a reaction suggestive of hypersensitivity during general anaesthesia in Clínica Universidad de Navarra (2008-2012) were included. Serum tryptase and plasma histamine were measured at the time of the reaction and 2 h later. Baseline tryptase was also determined. Four to eight weeks after the reaction an allergological study was performed to all the drugs or products involved in the reaction. RESULTS: Sixty-five patients suffered an immediate hypersensitivity reaction during the period of the study. Thirty-seven patients (20 male) with median age 48 years (12-79) were included because they completed allergological study, and histamine and tryptase were correctly obtained. Elevated plasma histamine was observed in 34 cases (92%). Tryptase exceeded twice the basal values in 10 patients (31%). Using different cut-off points of tryptase, the number of patients with elevated tryptase would be 15 patients (41%) for a cut-off point of 5 µg/L; 12 patients (32%) for a cut-off point of 8.23 µg/L; nine patients (24%) for 10.5 µg/L; and eight patients (22%) for 11.4 µg/L. The median tryptase level for the IgE-mediated reactions was 9.0 µg/L (2-70 µg/L) and 4.0 µg/L (3-13 µg/L) in non-IgE-mediated reactions (P < 0.01). Median tryptase levels were higher in more severe reactions (grade 2 or 3) in comparison with grade 1. The best ratio for serum-tryptase-during-reaction/basal-serum-tryptase to discriminate between IgE and non-IgE reactions was 2.0. CONCLUSION: The best criterion for discriminating IgE- and non IgE-mediated hypersensitivity reactions in anaesthesia was a tryptase value exceeding twice the basal one.

Early skin testing is effective for diagnosis of hypersensitivity reactions occurring during anesthesia.

Allergic skin tests have to be performed 4-6 weeks after an allergic anesthetic reaction. Patients with allergic reactions during anesthesia were prospectively included (n = 44). Skin tests were performed in two stages: (i) Stage 1 (S1), 0-4 days after the reaction; and (ii) Stage 2 (S2), 4-8 weeks after. Five (11.5%) surgical procedures were suspended due to the reaction. Positive skin tests were obtained in 25/44 patients (57%). Allergic diagnosis was carried out at S1 in 15/25 (60%) and at S2 in 10/25 (40%). Three patients resulted positive only in S1. Overall agreement among S1 and S2 skin tests was 70.45%. The kappa statistic was 0.41 (P-value = 0.002). Odds ratio of obtaining a false negative in S1 (compared with S2) was 3.33. Early allergological study is useful, could minimize false negatives, but should be considered as a complement to late skin tests.

Impact of Routine and Long-Term Follow-Up on Weight Loss after Bariatric Surgery.

BACKGROUND: Weight loss after bariatric surgery varies among patients. Patients who do not complete long-term follow-up are considered to loose less weight than those with regular follow-up visits. OBJECTIVE: To evaluate the influence of patients' follow-up compliance on long-term excess weight loss (%EWL) and total weight loss (%TWL) after bariatric surgery, comparing results between gastric bypass (GB) and sleeve gastrectomy (SG). METHODS: Patients with up to 5 years of follow-up data after bariatric surgery were included in this retrospective analysis. Patients were divided in 2 groups: those in group 1 who had attended every scheduled postoperative appointment and those in group 2 who had been lost to follow-up before 1 year and were later contacted by telephone. %EWL and %TWL were compared to determine the possible relationship between type of surgery and regularity of the follow-up. RESULTS: A total of 385 patients were included. A significant difference in EWL was observed at 5 years in the SG group (78% for group 1 versus 39% for group 2; p = 0.02) and GB group (75% for group 1 versus 62% for group 2; p = 0.01). No significant differences between surgeries were found when comparing long-term EWL in group 1 patients 77% for SG versus 75% for GB. For group 2 patients, GB achieved greater EWL than SG; p = 0.005. %TWL patients in group 2 showed significant differences in all periods of study (p < 0.05). CONCLUSION: Bariatric surgery patients who attended all scheduled follow-up appointments experienced significantly greater long-term EWL and TWL than those who did not. GB has apparent increased benefits for weight loss in long-term follow-up when compared with SG for patients who did not attend long-term follow-up. Therefore, continued long-term follow-up of bariatric patients should be encouraged to increase postoperative weight loss results.

Theory, simulation and experiments for precise deflection control of radiotherapy electron beams.

Conventional radiotherapy is mainly applied by linear accelerators. Although linear accelerators provide dual (electron/photon) radiation beam modalities, both of them are intrinsically produced by a megavoltage electron current. Modern radiotherapy treatment techniques are based on suitable devices inserted or attached to conventional linear accelerators. Thus, precise control of delivered beam becomes a main key issue. This work presents an integral description of electron beam deflection control as required for novel radiotherapy technique based on convergent photon beam production. Theoretical and Monte Carlo approaches were initially used for designing and optimizing device´s components. Then, dedicated instrumentation was developed for experimental verification of electron beam deflection due to the designed magnets. Both Monte Carlo simulations and experimental results support the reliability of electrodynamics models used to predict megavoltage electron beam control.

Mapping public policy options responding to obesity: the case of Spain.

This study assesses the opinions of the main Spanish stakeholders from food and physical exercise policy networks on public policy options for responding to obesity. We followed the multi-criteria mapping methodology in the framework of the European project 'Policy options in responding to obesity' (PorGrow), through a structured interview to 21 stakeholders. A four-step approach was taken: options, criteria, scoring and weighting, obtaining in this way a measure of the performance of each option which integrates qualitative and quantitative information. In an overall analysis, the more popular policy options where those grouped as educational initiatives: include food and health in the school curriculum, improve health education to the general public, improve the training of health professionals in obesity care and prevention, incentives to caterers to provide healthier menus and improve community sports facilities. Fiscal measures as subsidies and taxes had the lowest support. The criteria assessed as priorities were grouped as efficacy and societal benefits. Obesity in Spain can be approached through public policies, although the process will not be easy or immediate. The feasibility of changes requires concerned public policymakers developing long-term actions taking into account the map of prioritized options by the stakeholders.

Subcellular localization and properties of adenosine diphosphatase in human placenta.

It was found that mitochondria from human placenta exhibited an ADPase activity with the following characteristics. The enzyme responsible for this activity was associated with the inner mitochondrial membrane. It was not released by treatment of the submitochondrial particles with solutions of high ionic strength. Maximal ADP hydrolysis was reached at pH 8. Specific inhibitors for alkaline phosphatase (L-phenylalanine), myokinase (P1,P5-di(adenosine-5')pentaphosphate), or 5'-nucleotidase (concanavalin A) did not decrease ADP hydrolysis. ATP synthesis from ADP by myokinase was about 13 nmol/mg/min, whereas ADP hydrolysis reached values around 500 to 550 nmol/mg/min, indicating that a myokinase-H+ATPase combination could not account for the observed rates of ADP hydrolysis. The activity was stimulated by Mg2+, but high concentrations of this cation produced inhibition. High ADP concentrations did not inhibit ADPase activity. Kinetic measurements of the activity in the submitochondrial particles showed that the true substrate was ADP-Mg. The kinetic studies showed V(app) values of 476 and 270 nmol/mg/min, and Kmapp values of 416 and 8.7 microM.

Mediastinitis from odontogenic and deep cervical infection. Anatomic pathways of propagation.

Potentially lethal consequences can quickly occur once the mediastinum is subjected to the ravages of an anaerobic infection. Mediastinitis from odontogenic or deep cervical infections is extremely rare in the era of antibiotic drugs. We have recently encountered five such cases, with a rapid spread of the inflammatory process into the mediastinum resulting in a number of local and systemic complications. All were caused by anaerobic bacteria. Awareness of such complications and early roentgenographic diagnosis lead to prompt surgical drainage, proper antibiotic therapy, and survival after a stormy clinical course. The anatomic pathways between the various fascial planes of the neck and mediastinum will be described.

Cytogenetic interactions of contrast media and antineoplastic drugs.

The cytogenetic interactions of ionic (diatrizoate, ioxaglate) and nonionic (iohexol) contrast media (CM) with antineoplastic drugs cyclophosphamide (CPA) and carmustine (CARM) were evaluated in a rat bone marrow cell model. Male Wistar rats were anesthetized with a 6% chloral hydrate solution and divided into five groups of five rats each. In protocol 1, three groups of rats received diatrizoate, ioxaglate, and iohexol (2.5 mL/kg) intravenously within 30 seconds. The remaining two groups were similarly injected with CPA and CARM (10 mg/kg). Control animals were injected with nonpyrogenic sterile water or saline solution. After 12 and 24 hours, the animals were killed with an overdose of chloral hydrate, and bone marrow smears were prepared for determining chromosomal damage in polychromatic erythrocytes (PCEs) by a micronucleus test. In protocol 2, CPA and CARM were injected, and 15 minutes later, bolus injections of diatrizoate, ioxaglate and iohexol were given through the same route. Both ionic and nonionic CM induced significant numbers of micronuclei in PCEs (P less than .05). CPA caused a severe cytogenetic effect, whereas CARM did not produce a significant number of micronuclei in PCEs compared with control. In protocol 2 experiments, antagonism with CPA and synergism with CARM was demonstrable. Clinical implication of the cytogenetic interactions between CM and antineoplastic drugs remains to be established.

Ultrastructural changes in rat aortic endothelium during contrast media infusion.

A rat model was employed to investigate contrast media (CM) induced ultrastructural changes in the vascular endothelium. Ionic contrast materials such as Renografin-76 (diatrizoate meglumine diatrizoate sodium), MD-76 (diatrizoate meglumine diatrizoate sodium), and Angiovist (meglumine diatrizoate) were injected into the femoral vein of anesthetized male Wistar rats (240-260 g) and allowed to circulate. Control animals were similarly injected with equiosmolar sucrose and physiologic saline. The thorax was opened 15 minutes, 1 hour, and 4 hours postinjection and cardiac perfusion performed using Karnovsky's fixative; the thoracic aorta was then surgically removed, and processed for transmission electron microscopy. All CM produced shrinkage in cell cytoplasm and nuclear structures thereby causing distortions in cell morphology. In control tissues, however, no such ultrastructural damages were noted. Within 15 minutes of CM infusion, electron dense granules were seen on the luminal surface of endothelial cells, in pinocytotic vesicles, as well as in the gap junctions between cells. These observations indicate that contrast media intake occurs via vesicular transport, and through the cell junction.

Contrast media-induced lipid peroxidation in the rat kidney.

Lipid peroxidation of biological membranes is often implicated in tissue injury. The authors compared the effects of ionic and nonionic contrast media (CM) on the induction of lipid peroxidation in rat kidney and its impact on renal function. Male Wistar rats weighing 200 to 230 grams were dehydrated for 24 hours and divided into 6 groups (n = 15/group). On day 0, groups 1 through 3 were injected with 25% glycerol (10 mL/kg, im) and rats from groups 4 through 6 received an equivalent amount of intramuscular saline. The next day, rats from groups 1 and 4 were injected with normal saline (10 mL/kg, iv); groups 2 and 5 received the ionic CM, diatrizoate, and groups 3 and 6 received the nonionic CM, iopromide. Each CM was tested at 10 mL/kg BW. At 24-hour intervals, 5 rats from each group were sacrificed. In rats injected with CM (diatrizoate or iopromide) alone, no changes in serum creatinine or kidney structure were demonstrated. In glycerol treated rats, a peak in serum creatinine was seen on day 2 which returned to normal level by day 4. Histologic changes included focal tubular damage and intraluminal debris. Malondialdehyde (MDA), a marker of lipid peroxidation concentration was higher than in controls (P less than 0.05). In diatrizoate-injected rats, increase in serum creatinine on day 4 was ten times higher than glycerol; severe morphological alterations in proximal tubules were noted and significant increases in renal MDA concentration were obtained (P less than .05). Iopromide (on day 4), caused a five-fold increase in serum creatinine compared with glycerol.(ABSTRACT TRUNCATED AT 250 WORDS)

Contrast media-induced chromosomal damage in human lymphocyte cultures.

Ionic (diatrizoate, ioxaglate) and nonionic (iohexol, iosimide, iopromide, and iotrolan) contrast media (CM) were evaluated for their cytogenetic effects in lymphocytes. Heparinized blood was mixed with culture medium RPMI-1640 supplemented with phytohemagglutinin, fetal calf serum, and antibiotics. Plastic tubes containing blood samples were incubated at 37 degrees C in 5% CO2 humidified air for 48 hours. To these cultures, increasing amounts of CM were added and cells incubated for an additional 24 hours. After this exposure, red blood cells were lysed with hypotonic KC1, lymphocyte smears fixed on glass slides and stained with May-Grünwald Giemsa. Chromosomal damage was analyzed by a micronucleus test. All CM tested induced micronuclei in lymphocytes quite significantly (P less than .001) when compared with the frequency of micronuclei in controls. These observations on the genotoxic potential of nonionic CM suggest that factors other than ionic composition and osmolality are involved in clastogenesis; further studies are needed to establish the molecular mechanisms in CM induced chromosomal damage.

Antiplatelet action of intravascular contrast media. Implications in diagnostic procedures.

The antiplatelet action of intravascular contrast media (CM) Renografin-76 (diatrizoate meglumine and diatrizoate sodium) was studied in vitro and in 21 patients undergoing radiodiagnostic procedures. In vitro studies suggested that in Renografin-76, meglumine was the chief constituent responsible for its antiplatelet action. In post-CM plasma from patients, clotting times were prolonged and platelet aggregation greatly impaired, albeit normal aggregation restored within 3 hours. Although changes in global clotting times and platelet aggregation were mostly transient, it is possible that CM usage in patients with thrombocytopenia, sickle cell phenomenon, and on anticoagulant-antiplatelet drugs may present a serious risk to their hemostatic integrity.

Effect of contrast media on prostaglandin synthesis in vivo.

Since systemic reactions to contrast media (CM) in patients often resemble pathophysiologic conditions associated with prostaglandin metabolites prostacyclin (PGI2), and thromboxane B2 (TXB2), plasma levels of these mediators are likely to provide an index of CM pathogenesis. In this study, patients undergoing peripheral arteriography were injected either with a hyperosmolal CM sodium diatrizoate or with a newer low osmolal CM, iohexol. Arterial blood samples were collected before and after the procedure. Prostacyclin and thromboxane were quantified as 6 ketoprostaglandin F1a (PGF1a) and TXB2 by using radioimmunoassay kits. Diatrizoate caused prostaglandin I2 (PGI2) release in 60% of patients, whereas 66% receiving iohexol also exhibited increased levels of PGI2 in their plasma. TXB2 concentration remained unchanged. No clinically adverse reactions were seen following the procedure. These results indicate that both high and low osmolality CM are capable of stimulating vascular endothelium, thereby causing prostacyclin release. Molecular mechanisms, however, remain to be determined.