Multicenter Evaluation of AI-generated DIR and PSIR for Cortical and Juxtacortical Multiple Sclerosis Lesion Detection.

Background Cortical multiple sclerosis lesions are clinically relevant but inconspicuous at conventional clinical MRI. Double inversion recovery (DIR) and phase-sensitive inversion recovery (PSIR) are more sensitive but often unavailable. In the past 2 years, artificial intelligence (AI) was used to generate DIR and PSIR from standard clinical sequences (eg, T1-weighted, T2-weighted, and fluid-attenuated inversion-recovery sequences), but multicenter validation is crucial for further implementation. Purpose To evaluate cortical and juxtacortical multiple sclerosis lesion detection for diagnostic and disease monitoring purposes on AI-generated DIR and PSIR images compared with MRI-acquired DIR and PSIR images in a multicenter setting. Materials and Methods Generative adversarial networks were used to generate AI-based DIR (n = 50) and PSIR (n = 43) images. The number of detected lesions between AI-generated images and MRI-acquired (reference) images was compared by randomized blinded scoring by seven readers (all with >10 years of experience in lesion assessment). Reliability was expressed as the intraclass correlation coefficient (ICC). Differences in lesion subtype were determined using Wilcoxon signed-rank tests. Results MRI scans of 202 patients with multiple sclerosis (mean age, 46 years ± 11 [SD]; 127 women) were retrospectively collected from seven centers (February 2020 to January 2021). In total, 1154 lesions were detected on AI-generated DIR images versus 855 on MRI-acquired DIR images (mean difference per reader, 35.0% ± 22.8; P < .001). On AI-generated PSIR images, 803 lesions were detected versus 814 on MRI-acquired PSIR images (98.9% ± 19.4; P = .87). Reliability was good for both DIR (ICC, 0.81) and PSIR (ICC, 0.75) across centers. Regionally, more juxtacortical lesions were detected on AI-generated DIR images than on MRI-acquired DIR images (495 [42.9%] vs 338 [39.5%]; P < .001). On AI-generated PSIR images, fewer juxtacortical lesions were detected than on MRI-acquired PSIR images (232 [28.9%] vs 282 [34.6%]; P = .02). Conclusion Artificial intelligence-generated double inversion-recovery and phase-sensitive inversion-recovery images performed well compared with their MRI-acquired counterparts and can be considered reliable in a multicenter setting, with good between-reader and between-center interpretative agreement. Published under a CC BY 4.0 license. Supplemental material is available for this article. See also the editorial by Zivadinov and Dwyer in this issue.

Identification and Characterization of Leptomeningeal Metastases Using SPINE, A Web-Based Collaborative Platform.

BACKGROUND AND PURPOSE: Leptomeningeal metastases (LMs) carry a poor prognosis. Existing LM scoring systems show limited reproducibility. We assessed the contribution of education level on the reproducibility of LM scoring using structured planning and implementation of new experiments (SPINE), a novel web-based platform. METHODS: Stringent radiological definitions of LM and a customized interactive scoring system were implemented in SPINE. Five patients with brain LM and 3 patients with spine, but no brain LM, were selected. Each patient's baseline post-contrast T1-weighted brain MRI was analyzed by three attending neuroradiologists, two neuroradiology fellows, and two radiology residents. Raters identified and characterized all LMs based on: (1) location (cerebrum, cerebellum, brainstem, ventricle, and/or cranial nerves); (2) shape (nodular and/or linear/curvilinear); (3) size (≥ or <5mm in two orthogonal diameters); (4) spatial extension (focal or diffuse). Inter-rater agreement and association of LM with patient survival were investigated. RESULTS: On average, 6.5 LMs per case were detected. Forty-nine percent of LMs were cerebral, 77.7% were nodular, 86.6% were focal, and 66% were <5 × 5 mm. Agreement on the total number of LMs and the above-mentioned common LM characteristics was higher between attendings (intra-class correlation [ICC] = 0.8-0.94) than fellows (ICC = 0.6-0.82) or residents (ICC = 0.43-0.73). Agreement on ventricular, cranial nerve, and nodular + linear LM was low even between attendings. The number of brainstem LMs showed significant correlation with survival. CONCLUSION: Structured education using SPINE may improve consistency in LM reporting. Future work should address the impact of the presented approach on the reproducibility of longitudinal analyses directly relevant to the assessment of treatment-response.

Tempol, a Membrane-Permeable Radical Scavenger, Exhibits Anti-Inflammatory and Cardioprotective Effects in the Cerulein-Induced Pancreatitis Rat Model.

To date, it remains unclear whether mild form of acute pancreatitis (AP) may cause myocardial damage which may be asymptomatic for a long time. Pathogenesis of AP-related cardiac injury may be attributed in part to ROS/RNS overproduction. The aim of the present study was to evaluate the oxidative stress changes in both the pancreas and the heart and to estimate the protective effects of 1-oxyl-2,2,6,6-tetramethyl-4-hydroxypiperidine (tempol) at the early phase of AP. Cerulein-induced AP led to the development of acute edematous pancreatitis with a significant decrease in the level of sulfhydryl (-SH) groups (oxidation marker) both in heart and in pancreatic tissues as well as a substantial increase in plasma creatine kinase isoenzyme (CK-MB) activity (marker of the heart muscle lesion) which confirmed the role of oxidative stress in the pathogenesis of cardiac damage. The tempol treatment significantly reduced the intensity of inflammation and oxidative damage and decreased the morphological evidence of pancreas injury at early AP stages. Moreover, it markedly attenuated AP-induced cardiac damage revealed by normalization of the -SH group levels and CK-MB activity. On the basis of these studies, it is possible to conclude that tempol has a profound protective effect against cardiac and pancreatic damage induced by AP.

The influence of intravenous ondansetron on maternal blood haemodynamics after spinal anaesthesia for caesarean section: a double-blind, placebo-controlled study.

OBJECTIVE: verification of a hypothesis assuming that 5-HT3 receptor blockade by intravenous administration of ondansetron reduces the incidence of hypotension and bradycardia in patients undergoing spinal anaesthesia for Caesarean section. MATERIAL AND METHODS: The study design was approved by the Bioethics Committee and included 72 patients undergoing elective Caesarean section, randomly assigned to ondansetron group (group 0) or placebo group (group P). Finally group 0 encompassed 35 patients administered ondansetron 8 mg i.v. dissolved in 10 ml 0.9% NaCl whereas group P consisted of 34 patients receiving 0.9% NaCl 10 mg. Systolic and diastolic pressures were measured every 2 minutes since the onset of anaesthesia. Heart rate (HR) was monitored continuously The criterion of hypotension requiring ephedrine was a decrease in systolic pressure by 20% compared to its baseline value or a decrease in systolic pressure below 90 mm Hg. The criterion of bradycardia was a decrease in HR below 60/min. RESULTS: Hypotension was observed in 14 group 0 patients (39%) and in 15 group P patients (44%); the difference was not statistically significant. Bradycardia was noted in 1 group 0 patient (3%) and in 2 group P patients (6%); the difference was not statistically significant. CONCLUSION: A hypothesis assuming a reduction in pressure following subarachnoid anaesthesia for Caesarean section after the administration of 8 mg of ondansetron was not confirmed.

Activity Coefficients at Infinite Dilution and Physicochemical Properties for Organic Solutes and Water in the Ionic Liquid 1-Ethyl-3-methylimidazolium trifluorotris(perfluoroethyl)phosphate.

New data of activity coefficients at infinite dilution, γ13∞, for 65 different solutes including alkanes, alkenes, alkynes, cycloalkanes, aromatic hydrocarbons, alcohols, thiophene, ethers, ketones, aldehydes, esters and water in the ionic liquid 1-ethyl-3-methylimidazolium trifluorotris(perfluoroethyl)phosphate, were determined using inverse gas chromatography within the temperature range from 318.15 to 368.15 K. This is a continuation of our study of ionic liquids based on this anion. The results are compared with the other trifluorotris(perfluoroethyl)phosphate ionic liquids. The γ13∞ values were used to calculate thermodynamic functions such as partial molar excess Gibbs energies [Formula: see text], enthalpies [Formula: see text] and entropies [Formula: see text] as well as gas-liquid partition coefficients of the solutes, KL. These values were used to determine the linear free energy relationship (LFER) system constants as a function of temperature. The selectivities at infinite dilution needed for some extraction problems were calculated and compared with literature data of ionic liquids based on the trifluorotris(perfluoroethyl)phosphate anion and the 1-ethyl-3-methylimidazolium cation. Additionally, the density and viscosity of the investigated ionic liquid at temperatures from 298.15 to 348.15 K were measured.

Interspecies comparison of chlorinated contaminant concentrations and profiles in wild terrestrial mammals from northwest Poland.

The aim of this study was to determine residual polychlorinated biphenyls (PCBs) and organochlorine pesticides in the adipose tissue of wild terrestrial mammals coming from the same area in northwest Poland and to compare the organochlorine content and profile between species. The study was performed on five mammalian species, including omnivores (badger, wild boar, raccoon dog) and herbivores (roe deer, red deer). The obtained results show that the levels of residues of most of the analyzed compounds were greater in omnivorous mammals than herbivorous mammals. We found differences in the pattern of accumulation of organochlorines. In the raccoon dog organochlorines accumulated in the following descending order: DDTs > PCBs > HCHs > endrin > dieldrin; in the badger, wild boar, and roe deer, the order was as follows: DDTs > HCHs > PCBs > endrin > dieldrin; and in red deer, the order was as follows: HCHs > DDTs > PCBs > endrin > dieldrin. PCB 153 was dominant in herbivores and in the wild boar, whereas in the raccoon dog it was lower than PCB 138 and in badger lower than PCB 180. These differences in the tested species may reflect differences in metabolic capacity and/or feeding habits and an uneven distribution of organochlorines in the area where the animals lived. Maximum residue levels (MRLs) were exceeded in single samples from animals whose meat and fat can be consumed by humans. The greatest number of cases where MRLs were exceeded was observed in the adipose tissue of the badger (HCHs, DDTs, endrin, non-dioxin-like PCBs) and the fewest in the adipose tissue of roe deer (only lindane).

Wild boar (Sus scrofa) as a bioindicator of organochlorine compound contamination in terrestrial ecosystems of West Pomerania Province, NW Poland.

The aim of this study was to detect the presence and determine the residue levels of DDT, lindane, endrin and polychlorinated biphenyls (PCBs) in the liver of wild boars from the area of West Pomerania, NW Poland; to determine the activity of glutathione S-transferase (GST) as a biomarker of biological response and to assess the toxicological risk for consumers of the wild boar offal. The presence of pesticide residues and PCBs was found in all examined liver samples. The highest concentration was observed for endrin, and then, the descending order was PCBs >DDTs >lindane >dl-PCBs. The mean hepatic concentrations of endrin, PCBs, DDTs and lindane were 117.28, 78.59, 67.95 and 7.24 ng/g lipid weight, respectively. Among the dioxin-like PCB congeners, 118 and 156 were dominant in liver samples. The mean toxic equivalent (TEQ) level calculated for dl-PCBs was 2.10 ± 1.11 pg WHO-PCB-TEQ/g. There was a statistically significant (p < 0.05) negative correlation between the concentration of lindane, DDTs and PCBs (as a sum of indicator congeners) in the liver and in the activity of GST. However, GST activities showed no significant correlation with any of the dl-PCBs. In five boar liver samples, the levels of certain organochlorine compounds exceeded the maximum residue levels (MRLs). In one sample, the MRLs were exceeded simultaneously for PCBs, endrin and DDTs and in another one-for endrin and DDTs. In the remaining three samples, only PCB levels were exceeded.

The influence of epidural anesthesia on the electrical activity of heart atria.

INTRODUCTION: High thoracic epidural anesthesia (TEA) causes blockade of sympathetic fibers involved in innervation of the heart (segments T1-T4), which results in changes of cardiac electrophysiology. The anti-arrhythmic effects of TEA on supraventricular arrhythmias, mainly atrial fibrillation, are controversial. THE AIM OF THE STUDY: The aim of the study was to assess the influence of epidural anesthesia on the electrical function of heart atria, including proven markers of increased risk of perioperative atrial fibrillation, such as P wave dispersion and P wave maximum duration. MATERIAL AND METHODS: The study involved 50 male patients, without a history of previous heart diseases, scheduled for elective surgical procedures. Patients received thoracic epidural anesthesia (group T, n = 25) or lumbar epidural anesthesia (group L, n = 25). The measurements were obtained from a continuous recording of ECG before epidural anesthesia and after the detection of blockade (T1 or T8 segment sensory block in groups T and L, respectively). RESULTS: The statistical analysis of electrocardiographic parameters, including the maximum, minimum and mean P wave duration; P wave dispersion; the maximum, minimum and mean PR interval duration; and PR interval dispersion, did not show any inter- or intragroup differences at selected time points. CONCLUSIONS: Regardless of its location, epidural anesthesia and sympathetic blockade associated with this procedure do not significantly affect the electrical functions of the cardiac atria reflected in superficial ECG, including the electrocardiographic parameters that are considered to be markers of increased risk of perioperative atrial fibrillation, such as P wave dispersion and its maximum duration.

The impact of colloid infusion prior to spinal anaesthesia for caesarean section on the condition of a newborn--a comparison of balanced and unbalanced hydroxyethyl starch 130/0.4.

BACKGROUND: Fluid therapy is the most commonly used treatment to prevent hypotension associated with spinal anaesthesia. The aim of this study was to test the hypothesis that a balanced solution of 6% hydroxyethyl starch will have a more beneficial impact on the condition of newborns at birth than an unbalanced 6% solution of HES. METHODS: The study participants included 51 healthy parturients undergoing elective caesarean section with spinal anaesthesia. Patients received a transfusion of 500 mL of unbalanced 6% HES (Voluven) or balanced 6% HES (Tetraspan) prior to anaesthesia. The condition of the newborn was assessed using the Apgar score, and the acid-base balances of venous and arterial umbilical cord blood were also measured. RESULTS: The incidence of hypotension after spinal anaesthesia was 80% in Group A and 76.9% in Group B (P = 1.0). There were no differences between the two groups in the total doses of ephedrine and no differences between treatment groups in Apgar scores. Also, no differences in acid-base balance parameters (pH, H(+), pCO(2), pO(2), HCO(3)(-), BE) were found. CONCLUSION: A balanced 6% solution of hydroxyethyl starch (HES 130/0.42) did not significantly influence the condition of the newborns at birth or the acid-base and electrolyte concentration of newborns compared to an unbalanced solution of 6% hydroxyethyl starch (HES 130/0.4).

The influence of low flow anaesthesia on renal function in cancer patients previously treated with nephrotoxic chemotherapeutic agents.

BACKGROUND: The aim of this study was to assess renal morbidity, associated with the use of low flow anaesthesia (LFA), in cancer patients previously treated with nephrotoxic chemotherapeutic agents. METHODS: Seventy-five patients, aged 30-70 years, scheduled for elective surgery, were randomly allocated to three groups: Group A included those patients who had received nephrotoxic chemotherapeutic agents (cisplatin, carboplatin, methotrexate or cyclophosphamide) within 90 days before surgery, and who were anaesthetised with low flow (0.8(-1) L min(-1)) air-oxygen-sevoflurane (1-3 MAC) anaesthesia; Group B included similar patients who received high flow (6 L min-1) anaesthesia. Non-cancer patients receiving low flow anaesthesia served as controls. Blood was sampled for serum creatinine, BUN, cistatin C, and electrolytes (Na(+), K(+), Cl(-), Ca(2+), P(3+), Mg(2+)) before anaesthesia, and one, three and five days after. RESULTS: There were no statistically significant differences between the groups. CONCLUSIONS: The use of low flow sevoflurane anaesthesia is not associated with an increased risk of nephrotoxicity in those previously exposed to nephrotoxic chemotherapeutic agents.

Increase in intra-abdominal pressure raises brain venous pressure, leads to brain ischaemia and decreases brain magnesium content.

BACKGROUND: Intra-abdominal hypertension (IAH) may increase brain venous pressure, which may lead to brain injury. The aim of the present study was to analyse the effect of IAH on brain venous pressure and brain total and ionised magnesium (tMg and iMg), calcium (Ca) and zinc (Zn) contents in rats. MATERIAL AND METHODS: Forty four adult Wistar rats were examined. Animals were divided into two groups: control, and IAH: rats with intra-abdominal pressure (IAP) elevated to 25 mmHg. IAP was measured directly in the abdominal cavity. After retrograde cannulation of the jugular vein, the jugular venous pressure (JVP) was measured as the brain venous pressure. JVP and IAP were noted after induction of anaesthesia, immediately following induction of IAH and 90 min after induction of IAH. In all rats, brains were removed for biochemical and histological analysis. RESULTS: Biochemical analysis was performed in 30 rats, histological visualisation in 14. IAP elevated to 25 mmHg increased JVP in the IAH group. After 90 min, JVP decreased; however, its value was still higher compared with pre-IAH. In the IAH group, tMg and iMg were significantly lower than in the control group. Moreover, Ca and Zn levels were higher in the IAH group compared with the control group. The histological examination showed changes indicative of ischaemic neuronal cell stress. CONCLUSIONS: Firstly, increase in IAP elevates JVP. Secondly, raised JVP decreases tMg and iMg. Thirdly, raised JVP increases the Ca and Zn content in the rat brain. Fourthly, IAH leads to changed characteristics of brain ischaemia.

The Hildebrand solubility parameters of ionic liquids-part 2.

The Hildebrand solubility parameters have been calculated for eight ionic liquids. Retention data from the inverse gas chromatography measurements of the activity coefficients at infinite dilution were used for the calculation. From the solubility parameters, the enthalpies of vaporization of ionic liquids were estimated. Results are compared with solubility parameters estimated by different methods.

Relationship between selenium and selected heavy metals concentration in serum of cattle from a non-polluted area.

The present study was undertaken to evaluate the concentration of selenium and selected heavy metals and their possible relationship in serum of 25 healthy lactating cows (Montbéliarde) reared in a non-polluted area, in the western part of Poland. Cadmium, lead, copper, and zinc concentrations were determined by inductively coupled plasma-atomic emission spectrometry and Se concentration was determined fluorimetrically. The content of Se, Zn, and Cu was 0.083 ± 0.026, 0.629 ± 0.413, and 0.152 ± 0.042 µg/mL, respectively. The presence of the Cd and Pb was found in all serum samples. The mean concentration of these metals was 0.0009 ± 0.0008 and 0.018 ± 0.016 µg/mL, respectively. Analysis of correlations between Se and toxic metals showed a negative and significant (P < 0.05) relationship between selenium concentration and lead and cadmium concentration in the serum of the animals studied, with correlation coefficients of r = -0.595 and r = -0.618, respectively. For copper and zinc, this relationship was also negative but not significant (r = -0.255 and r = -0.203). Our study demonstrated that the level of toxic metals decreased as serum selenium concentration increased. It seems necessary to conduct further research on the interactions between these elements in blood, serum, and target organs concomitantly with the determination of their intake.

Physicochemical properties and activity coefficients at infinite dilution for organic solutes and water in the ionic liquid 1-decyl-3-methylimidazolium tetracyanoborate.

The activity coefficients at infinite dilution γ(13)(∞) and gas−liquid partition coefficients K(L) for 43 solutes­alkanes, alkenes, alkynes, cycloalkanes, aromatic hydrocarbons, alcohols, carboxylic acids, thiophene, ethers, ketones, and water­in the ionic liquid 1-decyl-3-methylimidazolium tetracyanoborate ([dmim][TCB]) were determined by gas−liquid chromatography at temperatures from 318.15 to 378.15 K. The partial molar excess Gibbs energies ΔG(1)(E,∞), enthalpies ΔH(1)(E,∞), and entropies ΔS(1)(E,∞) at infinite dilution were calculated from the experimental γ(13)(∞) values obtained over the temperature range. Additionally, the densities for investigated ionic liquid over the temperature range were determined. The selectivities for the aliphatic/aromatic hydrocarbon separation problem were calculated from γ(13)(∞) and compared to the literature values for N-methyl-2-pyrrolidinone (NMP) and sulfolane. It was found that the investigated [dmim][TCB] ionic liquid shows much higher capacity than NMP and sulfolane and selectivity on the same level as NMP and lower than that for sulfolane for the separation of aliphatic hydrocarbons from aromatic hydrocarbons.

The differentiating effect of glimepiride and glibenclamide on paraoxonase 1 and platelet-activating factor acetylohydrolase activity.

AIMS: The present study was designed to examine the effect of sulphonylureas, glimepiride (GM) and glibenclamide (GB), on paraoxonase 1 (PON1) and platelet activating factor acetylohydrolase (PAF-AH) activity in normal and streptozotocin (STZ)-induced (50 mg/kg) diabetic rats. MAIN METHODS: In treated groups, glimepiride (0.1 mg/kg) or glibenclamide (2 mg/kg) was given orally for 4 weeks. A PON1 and PAF-AH activity were estimated by spectrophotometric method. KEY FINDINGS: Hyperglycemia was accompanied by a significant decrease in plasma PON1 activity toward paraoxon (P < 0.001) and phenyl acetate (P < 0.01) and increase in plasma PAF-AH activity (P < 0.01). In STZ-induced diabetic rats the administration of both GM and GB had no effect on plasma PON1 activity but reversed elevated plasma PAF-AH activity (GM: P < 0.05, GB: P < 0.01). In non-diabetic rats after either GM or GB administration the decreased PON1 activity in the plasma was observed (GM: P < 0.001, GB: P < 0.05), but plasma PAF-AH activity remained unchanged. Both GM and GB had no effect on total plasma antioxidant capacity in diabetic and control treated groups. Additionally, both drugs increased PON1 activity toward phenyl acetate in the liver, in diabetic rats (GM: P < 0.05, GB:ns) as well as in non-diabetic rats (GM: P < 0.001, GB: P < 0.001), and reduced lipid peroxidation in the liver. SIGNIFICANCE: These results demonstrate that in streptozotocin-induced diabetic rats as well as in normal rats glimepiride and glibenclamide have no beneficial effects on circulating PON1 and PAF-AH activities, but both drugs increase PON1 activity in the liver.

The solubility parameters of ionic liquids.

The Hildebrand's solubility parameters have been calculated for 18 ionic liquids from the inverse gas chromatography measurements of the activity coefficients at infinite dilution. Retention data were used for the calculation. The solubility parameters are helpful for the prediction of the solubility in the binary solvent mixtures. From the solubility parameters, the standard enthalpies of vaporization of ionic liquids were estimated.

Activity coefficients at infinite dilution measurements for organic solutes and water in the ionic liquid 1-(3-hydroxypropyl)pyridinium trifluorotris(perfluoroethyl)phosphate.

The activity coefficients at infinite dilution, gamma(13)(infinity), for 37 solutes, alkanes, alkenes, alkynes, cycloalkanes, aromatic hydrocarbons, alcohols, thiophene, ethers, ketones, and water, in the ionic liquid 1-(3-hydroxypropyl)pyridinium trifluorotris(perfluoroethyl)phosphate [N-C(3)OHPY][FAP] were determined by gas-liquid chromatography at the temperatures from 308.15 to 358.15 K. The partial molar excess enthalpies at infinite dilution values DeltaH(1)(E,infinity) were calculated from the experimental gamma(13)(infinity) values obtained over the temperature range. The selectivities for aliphatics/aromatics hydrocarbons separation problem were calculated from the gamma(13)(infinity) values and compared to the literature values for other ionic liquids, N-methylpyrrolidone (NMP) and sulfolane. It was found that the investigated [N-C(3)OHPY][FAP] ionic liquid shows much higher selectivity and capacity at infinite dilution than the generally used organic solvents such as NMP, sulfolane, and other ionic liquids.

Influence of cation structure on binary liquid-liquid equilibria for systems containing ionic liquids based on trifluoromethanesulfonate anion with hydrocarbons.

Binary liquid-liquid equilibria for 15 systems containing an ionic liquid (1-butyl-3-methylimidazolium trifluoromethanesulfonate, 1-butyl-3-methylpyridinium trifluoromethanesulfonate, 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate) with a hydrocarbon (n-hexane, n-heptane, cyclohexane, benzene, toluene) were measured by the dynamic method. The influence of cation structure of trifluoromethanesulfonate anion based ionic liquids on solubility of aliphatic and aromatic hydrocarbons is discussed.

Resistance to acute NO-mimetic and EDHF-mimetic effects of leptin in the metabolic syndrome.

AIMS: We examined mechanisms leading to the impairment of nitric oxide (NO) and endothelium-derived hyperpolarizing factor (EDHF)-dependent vasorelaxation in response to acutely administered leptin in rats with the metabolic syndrome. MAIN METHODS: Effects of leptin on blood pressure and NO and cGMP in the aortic wall were studied in four groups of rats: (1) lean control, (2) obese, fed "cafeteria diet" for 3months (hyperleptinemia and hyperinsulinemia), (3) hyperleptinemia induced by administration of exogenous leptin for 8days, and (4) fructose-fed, receiving 20% fructose in the drinking water for 8weeks (hyperinsulinemia with slightly elevated leptin). KEY FINDINGS: Stimulatory effect of leptin on NO and cGMP production in the aortic wall was impaired in obese and hyperleptinemic groups but not in the fructose group. In contrast, EDHF-mimetic effect of leptin was impaired in obese and fructose-fed but not in the hyperleptinemic group. Leptin increased tyrosine phosphorylation of insulin receptor substrate-1 (IRS-1) in the aortic wall, and this effect was impaired in obese and fructose-fed animals. The EDHF-mimetic effect of leptin was abolished by phosphoinositide 3-kinase inhibitor, wortmannin, whereas its effect on NO was not. In addition, IRS-1 phosphorylation at Ser(307) and Ser(612) was enhanced in obese and fructose-fed but not in hyperleptinemic rats. SIGNIFICANCE: These results indicate that: (1) long-term hyperleptinemia induces resistance to acute vascular NO-mimetic effect of leptin in obesity/metabolic syndrome, (2) leptin stimulates EDHF in IRS-1 and PI3K-dependent manner, and this effect is impaired in obesity due to excessive serine phosphorylation of IRS-1.

Activity coefficients at infinite dilution measurements for organic solutes and water in the ionic liquid 1-butyl-3-methylimidazolium trifluoromethanesulfonate.

The activity coefficients at infinite dilution, gamma 13 (infinity) for 32 solutes: alkanes, alkenes, alkynes, cycloalkanes, aromatic hydrocarbons, alcohols, thiophene, tetrahydrofurane, tert-butyl methyl ether, and water in the ionic liquid 1-butyl-3-methylimidazolium trifluoromethanesulfonate [BMIM][CF3SO3] were determined by gas-liquid chromatography at the temperatures from 298.15 to 368.15 K. The partial molar excess enthalpies at infinite dilution values Delta H 1 (E,infinity) were calculated from the experimental gamma 13 (infinity) values obtained over the temperature range. The selectivities for the hexane/benzene, cyclohexane/benzene, n-hexane/thiophene, n-decane/thiophene, cyclohexane/thiophene, toluene/thiophene, and oct-1-ene/thiophene separation problems were calculated from the gamma 13 (infinity). Obtained values were compared to the literature values for the other ionic liquids, NMP, and sulfolane.