TEP/TDM 18F-choline dans les récidives biologiques des cancers de la prostate traites par radiothérapie externe ou curiethérapie : impact du PSA et de sa cinétique

AimTo determine the impact of PSA and its kinetics on ¹⁸F-Choline PET/CT (FCH PET) ability to detect site of relapse in prostate cancer initially treated with external beam radiotherapy (EBRT) or brachytherapy (IBT).MethodsWe retrospectively enrolled PET FCH performed for suspicion of biochemical relapse after EBRT/IBT from January 2010 to January 2017 at Institut Curie. PSA_trigger, ΔPSA_nadir (PSA_trigger-PSA_nadir), PSA doubling time (PSA_dt) and velocity (PSA_vel) were compared between positive and negative results. Logistic regression analysis was used to determine the relationship between these parameters and PET ability to detect True Positives (TP).ResultsIn all, 271 FCH PET met the inclusion criteria: 169 after treatment with EBRT and 102 after IBT. Positivity rate was 67.9%, and 63.4% of TP were local relapses. Overall sensitivity and specificity were 81.2% and 71.0%. PSA_trigger was 3.32 ng/mL (interquartile space: IQS 2.28–5.77) when PET was negative and 5.15 ng/mL (IQS 3.16–10.17) when positive, ΔPSAnadir was respectively 2.76 ng/mL (IQS 1.84–4.69) and 4.57 ng/mL (IQS 2.48–8.85), PSA_dt 10.78 months (IQS 5.46–20.07) and 7.23 months (EI 2.58–14.14), and PSA_vel 2.16 ng/mL/year (EI 1.02–4.80) et 4.92 ng/mL/year (1.89–16.02) (P < 0.001). Positivity rate increased with PSA_trigger and ΔPSA_nadir. We found PSA_dt ≤ 9 months (P = 0.029; OR = 2.97, IC_95% [1.12–7.88]) and ΔPSA_nadir ≥ 3 ng/mL (P = 0.03; OR = 2.56, IC_95% [1.37–4.77]) to be independent predictive factors of PET sensitivity.ConclusionDetection of relapse after EBRT or IBT with PET FCH is influenced by PSA and its kinetics. In our study, PSA_dt and ΔPSA_nadir were independant predictors of PET performance, but initial treatment and tumor characteristics were not.     

Liquid chromatography–tandem mass spectrometry method for the simultaneous quantitative determination of the organophosphorus pesticides dimethoate,fenthion, diazinon and chlorpyrifos in human blood

Simultaneous determination of the organophosphorus pesticides dimethoate, fenthion, diazinon and chlorpyrifos in human blood by HPLC–tandem mass spectrometry was developed and validated. The pesticides were extracted by a simple one-step protein precipitation procedure. Chromatography was performed on a Luna C₁₈ (30 mm × 2.0 mm, 3 μm) column, using a step-gradient at a flow rate of 0.4 ml/min. The assay was linear from 0.5 to 100 ng/ml (r² > 0.992, n = 24) for all pesticides. The inter- and intra-day accuracy and precision for the method was 96.6–106.1% and <10%, respectively. The lower limit of quantification was 0.5 ng/ml. In conclusion, the method described displays analytical performance characteristics that are suitable for the quantification of these pesticides in cases of acute poisoning.     

Selective inhibition of human acetylcholinesterase by xanthine derivatives: In vitro inhibition and molecular modeling investigations

The commonly used beverage and psychostimulant caffeine is known to inhibit human acetylcholinesterase enzyme. This pharmacological activity of caffeine is partly responsible for its cognition enhancing properties. However, the exact mechanisms of its binding to human cholinesterases (acetyl and butyrylcholinesterase; hAChE and hBuChE) are not well known. In this study, we investigated the cholinesterase inhibition by the xanthine derivatives caffeine, pentoxifylline, and propentofylline. Among them, propentofylline was the most potent AChE inhibitor (hAChE IC₅₀ = 6.40 μM). The hAChE inhibitory potency was of the order: caffeine (hAChE IC₅₀ = 7.25 μM) < pentoxifylline (hAChE IC₅₀ = 6.60 μM) ? propentofylline (hAChE IC₅₀ = 6.40 μM). These compounds were less potent relative to the reference agent donepezil (hAChE IC₅₀ = 0.04 μM). Moreover, they all exhibited selective inhibition of hAChE with no inhibition of hBuChE (IC₅₀ > 50 μM) relative to the reference agent donepezil (hBuChE IC₅₀ = 13.60 μM). Molecular modeling investigations indicate that caffeine binds primarily in the catalytic site (Ser203, Glu334 and His447) region of hAChE whereas pentoxifylline and propentofylline are able to bind to both the catalytic site and peripheral anionic site due to their increased bulk/size, thereby exhibiting superior AChE inhibition relative to caffeine. In contrast, their lack of hBuChE inhibition is due to a larger binding site and lack of key aromatic amino acids. In summary, our study has important implications in the development of novel caffeine derivatives as selective AChE inhibitors with potential application as cognitive enhancers and to treat various forms of dementia.     

Apoptotic effects and glucose-6-phosphate dehydrogenase responses in liver and gill tissues of rainbow trout treated with chlorpyrifos

We investigated apoptotic effects and changes in glucose-6-phosphate dehydrogenase (G6PD) enzyme activity in liver and gill tissues of fish exposed to chlorpyrifos. Three different chlorpyrifos doses (2.25, 4.5 and 6.75 μg/L) were administrated to rainbow trout at different time intervals (24, 48, 72 and 96 h). Acute exposure to chlorpyrifos showed time dependent decrease in G6PD enzyme activity at all concentrations (p < 0.05). Immunohistochemical results showed that chlorpyrifos caused mucous cell loss in gill tissue and apoptosis via caspase-3 activation in fish. The present study suggested that chlorpyrifos inhibits G6PD enzyme and causes mucous cell loss in gill and apoptosis in gill and liver tissues.     

IGF-I mediated inhibition of leptin receptor expression in porcine hepatocytes

A study was conducted to elucidate hormonal control of leptin receptor gene expression in primary cultures of porcine hepatocytes. Hepatocytes were isolated from swine and seeded into T-25 flasks. Cultures were established in medium containing fetal bovine serum for one day and switched to serum-free medium (William's E medium and 1 ng/mL insulin) for the remainder of the 3 d culture period. For the final 24 h, medium was supplemented with porcine growth hormone (GH, 100 or 500 ng/mL), insulin-like growth factor 1 (IGF-1, 50 to 250 ng/mL) or triiodothyronine (T3, 100 ng/mL). RNA was extracted and relative quantitative RT-PCR was performed with primers for long form leptin receptor. Receptor expression was calculated relative to 18S rRNA. Insulin had no effect (P > 0.05), while T3 increased leptin receptor mRNA abundance (P < 0.05). Treatment with GH or IGF-I reduced leptin receptor expression (P < 0.05). Phosphorylation of ERK1/2 in response to acute leptin treatment was inhibited by previous exposure to GH or IGF-I. Hepatocytes secreted IGF-I under basal conditions and this was enhanced by GH addition. These data suggest porcine hepatocytes may be less sensitive to leptin stimulation due to the actions of endogenous IGF-I on leptin receptor expression.     

Evaluating agro-industrial by-products as dietary roughage source on growth performance of fattening steers

Silages from pineapple peel, sweet corn husk and cob mixed with bagasse and vinasse were evaluated to determine their chemical composition and fermentation characteristics as well as feeding performance in fattening steers. The experiment, which lasted 90 days, involved 48 fattening steers (264 ± 37.4 kg BW) randomly allocated to three diets. Treatments included: a control diet containing rice straw and molasses (T1); diet containing bagasse–vinasse mixture including sweet corn husk and cob silage (BS; T2); and diet containing bagasse–vinasse mixture including pineapple peel silage (BP; T3). All treatments included a commercial concentrate feed (13% CP) and ad libitum rice straw throughout the experiment. Results from chemical analysis showed that dry matter (DM) of BS was higher than BP (P < 0.05), whereas the protein content of BS and BP was similar (P > 0.05). For fermentation characteristics, pH in BP was lower than BS (P < 0.05); in addition, acetic and butyric acids in BS were higher than BP (P < 0.05). Findings from growth trial showed that total DM intake in steers fed T1 was higher compared to the other dietary treatments (P < 0.05), whereas the average BW gain was found to be grater in T3 steers (P < 0.05). As result from our findings, bagasse–vinasse mixture with pineapple peel silage appeared to be a viable feed ingredient in fattening steer diet and moreover it could become an economically feasible agro-industrial by-product for farmers.     

Aqueous and ethanolic extracts of Galinsoga parviflora and Galinsoga ciliata. Investigations of caffeic acid derivatives and flavonoids by HPTLC and HPLC-DAD-MS methods

Galinsoga ciliata Raf. Blake like Galinsoga parviflora Cav., comes from the Andes region. The chemical composition, activity and use are similar for both species. Galinsoga species are used in folk medicine as anti-inflammatory agents and accelerators for wound healing. Extracts are applied topically onto the skin to treat dermatological diseases, eczemas, lichens and hard-healing-wounds, and also to treat snakebites. Orally they used to cure flu and colds.In the studies using HPTLC method, different stationary phases, including unmodified silica gel, silica gels modified with CN, NH₂, DIOL and RP18 groups were tried. The best separation of the tested compounds was achieved on silica gel plates, when as mobile phases mixtures – ethyl acetate–acetic acid–formic acid–water (100:11:11:26, v/v/v/v), ethyl acetate–methanol–formic acid–water (50:3:4:6, v/v/v/v) and ethyl acetate–methyl ethyl ketone–formic acid–water (30:9:3:3, v/v/v/v) – were used. Using reference substances, in the examined extracts the presence of flavonoids: patulitrin, quercimeritrin, quercitagetrin, and phenolic acids – caffeic and chlorogenic acids was found.HPLC analyses of extracts were carried out on a reversed-phase Zorbax SB column (150 mm × 2.1 mm, 1.9 μm). The mobile phase (A) was water/acetonitrile/formic acid (95:5:0.1, v/v/v) and the mobile phase (B) was acetonitrile/formic acid (100:0.1, v/v). A linear gradient system was used: 0–30 min, 1–30% B. Application of HPLC-DAD-MS method confirmed the results obtained by HPTLC method. Moreover, in the tested extracts the presence of caffeoylglucaric acids as dominating compounds was detected.     

Characterizing response behavior of medaka (Oryzias latipes) under chemical stress based on self-organizing map and filtering by integration

Behavioral responses (BRs) of medaka (Oryzias latipes) were observed after exposure to low concentrations (0.1 TU (Toxic Unit, TU), 1 TU, 5 TU, and 10 TU) of trichlorfon, parathion and malathion. Overall response patterns of test organisms were reflected from surface shapes of BS (Behavior Strength) values in 3-D: parathion appeared to be most variable in presenting response behaviors whereas trichlorfon showed relatively simple response patterns. The self-organizing map (SOM) addressed the time and toxic effects efficiently. An evident circadian rhythm observed in the control diminished at a low concentration of toxic unit, and variability of toxic effects was accordingly observed according to chemicals and concentrations. Subsequently filtering by integration was conducted to time series BS values. The highly fluctuating nature of original BS values was filtered efficiently to produce linear fitting closely. Slopes of regression decreased monotonically as toxic concentrations increased. Residual curves of integral BS values from linear fitting were further used for determining different BS phases proposed by empirical observations; the positive and negative phases were in accordance with acclimation, adjustment and toxic effects in behavior response modes. According to inclination and declination periods observed in residual curves, new states of test organisms were further defined to present intoxicating and recovering tendencies Profiles based on residual curves of integral BS values were able to show landscape of response patterns across toxic concentrations in different chemicals. Computational methods for defining behavior states provide an objective ground for analyzing complex stress response and could be suitable in referencing toxic behavior modes of test organisms quantitatively.     

Saliva as a medium for aldosterone measurement in repeated sampling studies

BackgroundSaliva is a readily available biological fluid, making it convenient in diagnosis of diseases and in multi-sampling protocols. Several salivary steroids give a useful index of free plasma levels. Increased incidence of primary aldosteronism (PA) in approximately 10% of the hypertensive population has increased interest in the mineralocorticoid aldosterone.MethodsA biotinylated-aldosterone tracer and a commercially available antibody are used in a time-resolved fluorescence immunoassay (TR-FIA) to measure salivary aldosterone (SA). Saliva was collected in various multi-sampling protocols: Investigation of diurnal rhythm in healthy and PA patients, ACTH stimulation test and posture test in healthy subjects.ResultsMethod validation showed a sensitivity of 19 ng/L and intra-/inter-assay precision between 7.2–10.1% and 8.7–15.7%, respectively. SA correlated significantly (y = 0.2995x ± 0.01, r² = 0.60) to plasma aldosterone measured by a commercial radioimmunoassay. SA (median; 95%CI) was at 111 (95–127) ng/L in PA (n = 84) and 50 (44–56) ng/L in healthy subjects (n = 60). After change in posture, aldosterone increased in both, saliva (57 (47–63) ng/L to 95 (84–117) ng/L) and plasma (26 (26–41) ng/L to 135 (110–181) ng/L). Peak levels were reached after 1 h, and were higher in females than in males.ConclusionsSA correlates well to plasma aldosterone and mirrors responses during conditions of stress. SA is significantly higher in PA, and the diurnal rhythm seen in the healthy is blunted in PA. We additionally found gender-dependent differential responses to posture, with higher increases in females. Measurement of aldosterone in saliva presents a useful and convenient method for application in multi-sampling studies.     

Synthesis and cholinesterase inhibition of cativic acid derivatives

Alzheimer’s disease (AD) is a neurodegenerative disorder associated with memory impairment and cognitive deficit. Most of the drugs currently available for the treatment of AD are acetylcholinesterase (AChE) inhibitors. In a preliminary study, significant AChE inhibition was observed for the ethanolic extract of Grindelia ventanensis (IC₅₀ = 0.79 mg/mL). This result prompted us to isolate the active constituent, a normal labdane diterpenoid identified as 17-hydroxycativic acid (1), through a bioassay guided fractionation. Taking into account that 1 showed moderate inhibition of AChE (IC₅₀ = 21.1 μM), selectivity over butyrylcholinesterase (BChE) (IC₅₀ = 171.1 μM) and that it was easily obtained from the plant extract in a very good yield (0.15% w/w), we decided to prepare semisynthetic derivatives of this natural diterpenoid through simple structural modifications. A set of twenty new cativic acid derivatives (3–6) was prepared from 1 through transformations on the carboxylic group at C-15, introducing a C2–C6 linker and a tertiary amine group. They were tested for their inhibitory activity against AChE and BChE and some structure–activity relationships were outlined. The most active derivative was compound 3c, with an IC₅₀ value of 3.2 μM for AChE. Enzyme kinetic studies and docking modeling revealed that this inhibitor targeted both the catalytic active site and the peripheral anionic site of this enzyme. Furthermore, 3c showed significant inhibition of AChE activity in SH-SY5Y human neuroblastoma cells, and was non-cytotoxic.     

Bacterial Peptide deformylase inhibition of cyano substituted biaryl analogs: Synthesis,in vitro biological evaluation,molecular docking study and in silico ADME prediction

Herein, we report the synthesis and screening of cyano substituted biaryl analogs 5(a–m) as Peptide deformylase (PDF) enzyme inhibitors. The compounds 5a (IC₅₀ value = 13.16 μM), 5d (IC₅₀ value = 15.66 μM) and 5j (IC₅₀ value = 19.16 μM) had shown good PDF inhibition activity. The compounds 5a (MIC range = 11.00–15.83 μg/mL), 5b (MIC range = 23.75–28.50 μg/mL) and 5j (MIC range = 7.66–16.91 μg/mL) had also shown potent antibacterial activity when compared with ciprofloxacin (MIC range = 25–50 μg/mL). Thus, the active derivatives were not only potent PDF inhibitors but also efficient antibacterial agents. In order to gain more insight on the binding mode of the compounds with PDF, the synthesized compounds 5(a–m) were docked against PDF enzyme of Escherichia coli and compounds exhibited good binding properties. In silico ADME properties of synthesized compounds were also analyzed and showed potential to develop as good oral drug candidates.     

Simultaneous determination of bisoprolol and hydrochlorothiazide in human plasma by HPLC coupled with tandem mass spectrometry

A sensitive, specific and selective method has been developed for the simultaneous determination of bisoprolol and hydrochlorothiazide in human plasma. The method employed a state of the art LC–MS/MS operated in the positive and negative ionization switching modes. A simple sample preparation step involving protein precipitation with acetonitrile has been optimized; the analytes and the internal standard moxifloxacin were separated on a Purosphere^® STAR C₈ column (125 mm × 4 mm, 5 μm). The mobile phase was an ammonium acetate solution (1 mM) with formic acid (0.2%): methanol and acetonitrile (65:17.5:17.5, v/v/v (%)), the flow rate was set at 0.65 mL/min. Bisoprolol and hydrochlorothiazide were ionized using ESI source prior to detection by Multiple Reaction Monitoring (MRM) mode while monitoring at the following transitions: positive m/z 326 → 116 for bisoprolol, negative m/z 296 → 269 and m/z 296 → 205 for hydrochlorothiazide. Linearity was demonstrated over the concentration range 0.10–30.0 (ng/mL) for bisoprolol and 1.00–80.00 ng/mL for hydrochlorothiazide. The limits of detection were 0.100 (ng/mL) for bisoprolol and 1.00 (ng/mL) for hydrochlorothiazide. The validated method was successfully applied to a pharmacokinetic study of 5 mg bisoprolol fumarate with 12.5 mg hydrochlorothiazide tablet in healthy volunteers.     

Postoperative plasma copeptin levels independently predict delirium and cognitive dysfunction after coronary artery bypass graft surgery

Copeptin can reflect individual's stress state and are correlated with poor outcome of critical illness. The occurrence of postoperative delirium (POD) and cognitive dysfunction (POCD) is associated with worse outcome after coronary artery bypass graft (CABG) surgery. The present study aimed to investigate the ability of postoperative plasma copeptin level to predict POD and POCD in patients undergoing CABG surgery. Postoperative plasma copeptin levels of 108 patients were measured by an enzyme-linked immunosorbent assay. It was demonstrated that plasma copeptin levels were substantially higher in patients with POD than without POD (1.8 ± 0.6 ng/mL vs. 1.1 ± 0.3 ng/mL; P < 0.001) and in patients with POCD than without POCD (1.9 ± 0.6 ng/mL vs. 1.1 ± 0.4 ng/mL; P < 0.001). Plasma copeptin level and age were identified as independent predictors for POD [odds ratio (OR), 67.386; 95% confidence interval (CI), 12.031–377.426; P < 0.001 and OR, 1.202; 95% CI, 1.075–1.345; P = 0.001] and POCD (OR, 28.814; 95% CI, 7.131–116.425; P < 0.001 and OR, 1.151; 95% CI, 1.030–1.285; P = 0.003) using a multivariate analysis. For prediction of POD, the area under receiver operating characteristic curve (AUC) of the copeptin concentration (AUC, 0.883; 95% CI, 0.807–0.937) was markedly higher than that of age (AUC, 0.746; 95% CI, 0.653–0.825; P = 0.020). For prediction of POCD, the AUC of the copeptin concentration (AUC, 0.870; 95% CI, 0.792–0.927) was markedly higher than that of age (AUC, 0.735; 95% CI, 0.641–0.815; P = 0.043). Thus, postoperative plasma copeptin level may be a useful, complementary tool to predict POD and POCD in patients undergoing CABG surgery.     

Rat intestinal sucrase inhibition of constituents from the roots of Rosa rugosa Thunb.

A new octanordammarane triterpene, 3β,15α-dihydroxymansumbinol (1) and a novel A-ring contracted oleanane triterpenoid, 2-formyl-(A)1–19α-hydroxy-1-norolean-2,12-dien-28-oic acid (2) were isolated from the roots extract of Rosa rugosa along with fifteen known compounds (3–17). Their structures were elucidated by extensive spectroscopic analysis, including 1D and 2D NMR, and FTICRMS. The MeOH extract, as well as CH₂Cl₂ and EtOAc fractions at a concentration of 0.5 mg/mL showed potent sucrase inhibitory activity, with inhibition percentage values of 84.67 ± 5.37%, 87.50 ± 2.78%, and 81.91 ± 2.90%, respectively. In addition, compounds 7–13 (1.0 mM) showed potent sucrase inhibitory activity (61.88 ± 3.19% to 84.70 ± 3.07% inhibition), which was comparable to that of the positive control, acarbose, with an inhibition percentage value of 50.96 ± 2.97%. Compounds 1, 2, 4, and 14–17 showed moderate and/or weak inhibitory activities at the same concentration. The α-glucosidase inhibitory activities of the extracts and purified compounds may provide a novel opportunity to develop a new class of antidiabetic agents.     

Reproductive responses of ram lambs under short-term exposure to endophyte-infected tall fescue seed

Our objective was to determine the influence of short-term exposure to endophyte-infected tall fescue on reproductive function of ram lambs. Rams (214 days of age) were fed a diet free of endophyte-infected fescue seed (EF; n = 8) or endophyte-infected fescue seed (EI; n = 9; 34% of diet; 4.8 μg g⁻¹ ergovaline) for 6 weeks. Feed offered to EF rams, individually fed, was reduced to the average intake of EI lambs from previous day so that intake was similar between treatments and averaged 2.4% BW (DM basis), leading to daily intake of 33.7 μg ergovaline kg⁻¹ BW for the EI fed lambs. Daily high ambient temperature for the trial ranged between 16 and 26 °C. Respiration rate and rectal temperature were measured at 14:00 daily. Blood was collected for serum concentrations of prolactin (weekly) and testosterone (twice weekly). Body weight and body condition scores (BCS; 1 = thin; 5 = fat) were determined every 14 days. Scrotal circumference, scrotal skin temperature, and semen characteristics were determined weekly. Rams were slaughtered after 6 weeks of feeding. Signs of fescue toxicosis in EI fed rams included increased rectal temperature (P < 0.001, R² = 0.11) and respiration rate (day, P < 0.001, R² = 0.25) when high ambient temperature exceeded 22 °C and reduced serum concentrations of prolactin (diet × day, P < 0.001). Body weight of EI fed rams tended to decrease after 36 days of feeding compared with EF fed rams (−3.0 kg versus 0.51 kg; P < 0.07) and BCS was similar between treatment throughout the trial. Serum concentrations of testosterone were greater in EI compared with EF fed rams (diet × day, P < 0.005, R² = 0.08). Scrotal skin temperature, scrotal circumference, semen volume, percent sperm motility, and percent abnormal sperm were similar between treatments. Spermatozoa concentration tended to be greater in EF compared with EI fed rams after 43 days of feeding (P < 0.10; R² = 0.15). Rate of forward movement of spermatozoa tended to increase at a greater rate between Days 8 and 29 in EF compared with EI fed rams (diet × day, P < 0.08). Feeding endophyte-infected fescue seed to ram lambs was associated with potential decreased fertility and increased serum concentrations of testosterone. Short term exposure of endophyte toxins to male ruminants may negatively impact reproductive responses. Feeding for longer periods may further reduce fertility and merits further research.     

High serum osteopontin levels in pediatric patients with high risk Langerhans cell histiocytosis

Osteopontin (OPN) acts as an osteoclast activator, a proinflammatory cytokine, and a chemokine attracting histiocytes/monocytes and is abundantly expressed in Langerhans cell histiocytosis (LCH). We investigated whether serum OPN levels are related to disease types in LCH. Fifty-eight newly diagnosed LCH patients were studied; eight with risk organ (liver, spleen and/or hematopoietic) involvements positive multisystem (MS+) disease, 27 with risk organ involvement negative multisystem (MS−) disease and 23 with single system (SS) disease. Pediatric patients with non-inflammatory disease (n = 27) were used as controls. All of patients with MS+ disease were younger than 3 years. Serum OPN levels and 44 kinds of humoral factors were measured by ELISA and Bio-Plex suspension array system, respectively. In the patients younger than 3 years, the median serum OPN level (interquartile range) was 240.3 ng/ml (137.6–456.0) in MS+ (n = 8); 92.7 ng/ml (62.0–213.8) in MS− (n = 14) and 72.5 ng/ml (55.6–94.0) in SS (n = 9) and 74.4 ng/ml (42.2–100.0) in control (n = 12). The OPN values were significantly higher in the MS+ group than the MS−, SS and control groups (p = 0.044, p = 0.001 and p = 0.002, respectively), but not different between the MS−, SS and control groups. In the patients older than 3 years, the median level of serum OPN (IQR) was 56.2 ng/ml (22.9–77.5) in MS− (n = 13), 58.9 ng/ml (31.0–78.7) in SS (n = 14) and 41.9 (28.9–54.1) in control (n = 15). These values did not differ significantly between each group. The serum OPN levels were positively correlated with the serum IL-6, CCL2, IL-18, IL-8 and IL-2 receptor concentration. OPN may be involved in risk organ dissemination and poor prognosis of LCH through the function as inflammatory cytokine/chemokine.     

Simultaneous quantification of rosiglitazone and its two major metabolites,N-desmethyl and p-hydroxy rosiglitazone in human plasma by liquid chromatography/tandem mass spectrometry: Application to a pharmacokinetic study

We present a simple, rapid, and sensitive liquid chromatography (LC)–tandem mass spectrometry (MS/MS) method for the simultaneous quantification of rosiglitazone and its two major metabolites via CYP2C8/9, N-desmethyl and p-hydroxy rosiglitazone, in human plasma. The procedure was developed and validated using rosiglitazone-d₃ as the internal standard. Plasma samples (0.1 ml) were prepared using a simple deproteinization procedure with 0.2 ml of acetonitrile containing 40 ng/ml of rosiglitazone-d₃. Chromatographic separation was carried out on a Luna C₁₈ column (100 mm × 2.0 mm, 3-μm particle size) using an isocratic mobile phase consisting of a 60:40 (v/v) mixture of acetonitrile and 0.1% formic acid_(aq). Each sample was run at 0.2 ml/min for a total run time of 2.5 min per sample. Detection and quantification were performed using a mass spectrometer in selected reaction-monitoring mode with positive electrospray ionization at m/z 358.1 → 135.1 for rosiglitazone, m/z 344.2 → 121.1 for N-desmethyl rosiglitazone, m/z 374.1 → 151.1 for p-hydroxy rosiglitazone, and m/z 361.1 → 138.1 for rosiglitazone-d₃. The linear ranges of concentration for rosiglitazone, N-desmethyl rosiglitazone, and p-hydroxy rosiglitazone were 1–500, 1–150, and 1–25 ng/ml, respectively, with a lower limit of quantification of 1 ng/ml for all analytes. The coefficient of variation for assay precision was less than 14.4%, and the accuracy was 93.3–112.3%. No relevant cross-talk and matrix effect were observed. This method was successfully applied to a pharmacokinetic study after oral administration of a 4-mg rosiglitazone tablet to healthy male Korean volunteers.     

Syntheses of 4,6-dihydroxypyrimidine diones,their urease inhibition,in vitro,in silico,and kinetic studies

A library of 4,6-dihydroxypyrimidine diones (1–35) were synthesized and evaluated for their urease inhibitory activity. Structure-activity relationships, and mechanism of inhibition were also studied. All compounds were found to be active with IC₅₀ values between 22.6 ± 1.14–117.4 ± 0.73 µM, in comparison to standard, thiourea (IC₅₀ = 21.2 ± 1.3 µM). Kinetics studies on the most active compounds 2–7, 16, 17, 28, and 33 were performed to investigate their modes of inhibition, and dissociation constants K_i. Compounds 2, 3, 7, 16, 28, and 33 were found to be mixed-type of inhibitors with K_i values in the range of 7.91 ± 0.024–13.03 ± 0.013 µM, whereas, compounds 4–6, and 17 were found to be non-competitive inhibitors with K_i values in the range of 9.28 ± 0.019–13.05 ± 0.023 µM. In silico study was also performed, and a good correlation was observed between experimental and docking studies. This study is continuation of our previously reported urease inhibitory activity of pyrimidine diones, representing potential leads for further research as possible treatment of diseases caused by ureolytic bacteria.     

Facile synthesis and characterization of novel pyrazole-sulfonamides and their inhibition effects on human carbonic anhydrase isoenzymes

In the current study, a series of pyrazole-sulfonamide derivatives (2–14) were synthesized, characterized, and the inhibition effects of the derivatives on human carbonic anhydrases (hCA I and hCA II) were investigated as in vitro. Structures of these sulfonamides were confirmed by FT-IR, ¹H NMR, ¹³C NMR and LC–MS analysis. ¹H NMR and ¹³C NMR revealed the tautomeric structures. hCA I and hCA II isozymes were purified from human erythrocytes and inhibitory effects of newly synthesized sulfonamides on esterase activities of these isoenzymes have been studied. The K_i values of compounds were 0.062–1.278 μM for hCA I and 0.012–0.379 μM for hCA II. The inhibition effects of 7 for hCA I and 4 for hCA II isozymes were almost in nanomolar concentration range.