Tissue accumulation and toxicity of isothiazolinone in Ctenopharyngodon idellus (grass carp): Association with P-glycoprotein expression and location within tissues

Isothiazolinone is widely used as a broad-spectrum fungicide in various industries, such as oil, paper, pesticide, dyes, tanning and cosmetics. There is an increasing concern over protection of the aquatic environment due to its large-scale use. The acute toxicity (LC₅₀) of isothiazolinone in Ctenopharyngodon idellus was investigated. The residual time and accumulation in tissues, P-glycoprotein mRNA level and localization of P-glycoprotein in the liver and kidney were also analyzed. The LC₅₀ (48 h) values of isothiazolinone to C. idellus were 0.53 ± 0.17 mg/L and 0.41 ± 0.08 mg/L at 15 °C and 25 °C, respectively. The LC₅₀ values decreased as the temperature increased. The accumulation of isothiazolinone in livers and kidneys in the high temperature group (25 °C) was significantly greater than that of the low temperature group (15 °C). Prolonged tissue residual time of isothiazolinone was seen in all the groups. There were significant differences in P-glycoprotein mRNA expression between isothiazolinone-treated groups and control samples (P < 0.05–0.01). Temperature affected accumulation and toxicity of isothiazolinone.     

Optimization of mead production using Response Surface Methodology

The main aim of the present work was to optimize mead production using Response Surface Methodology. The effects of temperature (x₁: 20–30 °C) and nutrients concentration (x₂: 60–120 g/hL) on mead quality, concerning the final concentrations of glucose (Y₁), fructose (Y₂), ethanol (Y₃), glycerol (Y₄) and acetic acid (Y₅), were studied. Twelve operational conditions were tested. No delays and moods were observed during fermentations. The second order polynomial models determined produced satisfactory fittings of the experimental data with regard to glucose (R² = 0.646, p = 0.001), ethanol (R² = 0.741, p = 0.049), glycerol (R² = 0.899, p = 0.002), fructose (R² = 0.902, p = 0.033) and acetic acid (R² = 0.913, p = 0.001). The optimum extraction conditions determined in order to maximize the combined responses were 24 °C and a nutrients concentration of 0.88 g/L. The mead produced under these conditions had the following characteristics: ethanol concentration of 10.2%, acetic acid 0.54 g/L, glycerol 7.8 g/L, glucose 1.8 g/L and fructose 2.5 g/L. These values were in agreement with the predicted and were within the safe limit established for acetic acid and the recommended range for glycerol. Furthermore, the residual sugars concentration was also low, decreasing the possibility of occurring undesirable refermentations.     

Changes in ambient temperature differentially alter the thermoregulatory,cardiac and locomotor stimulant effects of 4-methylmethcathinone (mephedrone)

BackgroundThe substituted cathinone compound known as mephedrone (4-methylmethcathinone; 4-MMC) has become popular with recreational users of psychomotor-stimulant compounds. Only recently have the first preclinical studies provided information about this drug in the scientific literature; nevertheless, media reports have led to drug control actions in the UK and across several US states. Rodent studies indicate that 4-MMC exhibits neuropharmacological similarity to 3,4-methylenedioxymethamphetamine (MDMA) and prompt investigation of the thermoregulatory, cardiac and locomotor effects of 4-MMC. This study focuses on the role of ambient temperature, which has been shown to shift the effects of MDMA from hyperthermic to hypothermic.MethodsMale Sprague-Dawley rats were monitored after subcutaneous administration of 4-MMC (1.0–5.6 mg/kg) using an implantable radiotelemetry system under conditions of low (20 °C) and high (30 °C) ambient temperature.ResultsA pharmacokinetic study found a T_max of 0.25 h and a C_max of 1206 ng/ml after 5.6 mg/kg 4-MMC. A dose-dependent reduction of body temperature was produced by 4-MMC at 20 °C but there was no temperature change at 30 °C. Increased locomotor activity was observed after 4-MMC administration under both ambient temperatures, however, significantly more activity was observed at 30 °C. Heart rate was slowed by 1.0 and 5.6 mg/kg 4-MMC at 20 °C, and was slower in the 30 °C vs. 20 °C condition across all treatments.ConclusionThese results show that the cathinone analog 4-MMC exhibits in vivo thermoregulatory properties that are distinct from those produced by MDMA.     

Preparation and characterisation of novel chlorothiazide potassium solid-state salt forms: Intermolecular self assembly suprastructures

Chlorothiazide (CTZ) is a poorly soluble diuretic agent. The aim of the present work was to produce and characterise a potassium salt form of chlorothiazide which has the potential advantages of improved aqueous solubility and potassium supplementation. A number of novel potassium salt forms of CTZ (CTZK) were prepared: CTZK monohydrate (form I), CTZK dihydrate (form II), anhydrous CTZK (form III), CTZK monohydrate hemiethanolate (form IV) and a desolvate of CTZK monohydrate hemiethanolate (form V). These salt forms were characterised by thermal analysis, PXRD, NMR, elemental analysis, FTIR, Karl Fisher titrimetry, ICP-MS and GC–MS. The ethanol-free CTZK forms were also characterised by dynamic vapour sorption analysis (DVS). CTZK form I was stable (in the DVS) over the range 0–60% RH. The dihydrate form of the salt was stable (in the DVS) over a broader range of relative humidities, 10–90% RH at 25 °C. CTZK form II was less hygroscopic at high humidities (70–90% RH) than the previously reported CTZNa dihydrate. Single crystal X-ray analysis indicated that chlorothiazide potassium, crystallised from water or water/acetone mixture, formed a dihydrated polymeric-like intermolecular self-assembly (ISA) suprastructure. The ISA coordination was determined to be: (CTZ)₃·K·(H₂O)₂(CTZ)₂·(H₂O)₂·K·(CTZ)₃ (monoclinic, space group: C2/c, single crystal cell parameters: a = 18.328(4) Å, b = 7.3662(16) Å, c = 19.993(5) Å, α = 90°, β = 99.729(3)°, γ = 90°). When CTZK was crystallised from ethanol, a monohydrate hemiethanolate ISA was formed, described as (CTZ)₃·K·CTZ·(H₂O)₂·CTZ·K·(CTZ)₂ (triclinic, space group: P-1, single crystal cell parameters: a = 7.078(3) Å, b = 9.842(5) Å, c = 21.994(11) Å, α = 87.522(13)°, β = 84.064(14)°, γ = 78.822(12)°). The aqueous solubility of CTZK dihydrate, was determined to be 78.71 ± 1.82 mg/ml, approximately 400-fold higher than chlorothiazide, indicating a biopharmaceutical advantage associated with the potassium salt form.     

Investigation of PEG Crystallization in Frozen PEG-Sucrose-Water Solutions. I. Characterization of the Nonequilibrium Behavior during Freeze-Thawing

Our objective was to characterize the nonequilibrium thermal behavior of frozen aqueous solutions containing PEG and sucrose. Aqueous solutions of (i) sucrose (10%, w/v) with different concentrations of PEG (1–20%, w/v), and (ii) PEG (10%, w/v) with different concentrations of sucrose (2–20%, w/v), were cooled to ? 70°C at 5°C/min and heated to 25°C at 2°C/min in a differential scanning calorimeter. Annealing was performed at temperatures ranging from ? 50 to ? 20°C for 2 or 6 h. Similar experiments were also performed in the low-temperature stage of a powder X-ray diffractometer. A limited number of additional DSC experiments were performed wherein the samples were cooled to ? 100°C. In unannealed systems with a fixed sucrose concentration (10%, w/v), the T′_g decreased from ? 35 to ? 48°C when PEG concentration was increased from 1% to 20% (w/v). On annealing at ? 25°C, PEG crystallized. This was evident from the increase in T′_g and the appearance of a secondary melting endotherm in the DSC. Low- temperature XRD provided direct evidence of PEG crystallization. Annealing at temperatures ≤?40°C did not result in crystallization and a devitrification event was observed above the T′_g. In unannealed systems with a fixed PEG concentration (10%, w/v), the T′_g increased from ? 50 to ? 40°C when sucrose concentration was increased from 5% to 50%, w/v. As the annealing time increased (at ? 25°C), the T′_g approached that of a sucrose-water system, reflecting progressive PEG crystallization. A second glass transition at ~? 65°C was evident in unannealed systems [10%, w/v sucrose and 10 (or 20%), w/v PEG] cooled to ? 100°C. Investigation of the nonequilibrium behavior of frozen PEG-sucrose-water ternary system revealed phase separation in the freeze-concentrate. Annealing facilitated PEG crystallization.     

Chemical composition and anticancer,antiinflammatory, antioxidant and antimalarial activities of leaves essential oil of Cedrelopsis grevei

The essential oil from Cedrelopsis grevei leaves, an aromatic and medicinal plant from Madagascar, is widely used in folk medicine. Essential oil was characterized by GC–MS and quantified by GC–FID. Sixty-four components were identified. The major constituents were: (E)-β-farnesene (27.61%), δ-cadinene (14.48%), α-copaene (7.65%) and β-elemene (6.96%). The essential oil contained a complex mixture consisting mainly sesquiterpene hydrocarbons (83.42%) and generally sesquiterpenes (98.91%). The essential oil was tested cytotoxic (on human breast cancer cells MCF-7), antimalarial (Plasmodium falciparum), antiinflammatory and antioxidant (ABTS and DPPH assays) activities. C. grevei essential oil was active against MCF-7 cell lines (IC₅₀ = 21.5 mg/L), against P. falciparum, (IC₅₀ = 17.5 mg/L) and antiinflammatory (IC₅₀ = 21.33 mg/L). The essential oil exhibited poor antioxidant activity against DPPH (IC₅₀ > 1000 mg/L) and ABTS (IC₅₀ = 110 mg/L) assays. A bibliographical review was carried out of all essential oils identified and tested with respect to antiplasmodial, anticancer and antiinflammatory activities. The aim was to establish correlations between the identified compounds and their biological activities (antiplasmodial, anticancer and antiinflammatory). According to the obtained correlations, 1,4-cadinadiene (R² = 0.61) presented a higher relationship with antimalarial activity. However, only (Z)-β-farnesene (R² = 0.73) showed a significant correlation for anticancer activity.     

Toxicological effects of clofibric acid and diclofenac on plasma thyroid hormones of an Indian major carp,Cirrhinus mrigala during short and long-term exposures

In the present investigation, the toxicity of most commonly detected pharmaceuticals in the aquatic environment namely clofibric acid (CA) and diclofenac (DCF) was investigated in an Indian major carp Cirrhinus mrigala. Fingerlings of C. mrigala were exposed to different concentrations (1, 10 and 100 μg L⁻¹) of CA and DCF for a period of 96 h (short term) and 35 days (long term). The toxic effects of CA and DCF on thyroid hormones (THs) such as thyroid stimulating hormone (TSH), thyroxine (T₄) and triiodothyronine (T₃) levels were evaluated. During the short and long-term exposure period TSH level was found to be decreased at all concentrations of CA (except at the end of 14^th day in 1 and 10 μg L^−l and 21^st day in 1 μg L^−l) whereas in DCF exposed fish TSH level was found to be increased when compared to control groups. T₄ level was found to be decreased at 1 and 100 μg L^−l of CA exposure at the end of 96 h. However, T₄ level was decreased at all concentrations of CA and DCF during long-term (35 days) exposure period. Fish exposed to all concentrations of CA and DCF had lower level of T₃ in both the treatments. These results suggest that both CA and DCF drugs induced significant changes (P < 0.01 and P < 0.05) on thyroid hormonal levels of C. mrigala. The alterations of these hormonal levels can be used as potential biomarkers in monitoring of pharmaceutical drugs in aquatic organisms.     

Adsorption of hexavalent chromium in aqueous solution on activated carbon prepared from apple peels

In the present study, activated carbon prepared from apple peels (ACAP) was used to remove chromium (VI) from aqueous solution. The characterization of this ACAP has been performed using different analytical techniques such as FTIR and SEM. The adsorption parameters studied were: pH [2- 7], adsorbent dose [0.025–0.15 g/50 mL], initial Cr(VI) concentration [10–50 mg/L] and temperature [10–40 °C]. Maximum Cr(VI) adsorption of 36.01 mg/g was achieved using Cr(VI) concentration of 50 mg/L, pH of 2, adsorbent dose of 0.05 g/50 mL, contact time of 4 h and temperature of 28 °C. This ACAP gave a Cr(VI) adsorption capacity better than a commercial activated carbon. The experimental data fitted well to Freundlich isotherm (R² = 0.99) and kinetics followed the pseudo-second order model. Thermodynamic parameters, ΔG < 0, ΔH° = 1.99 (Kcal/mol) and ΔS° = 0.0079 (Kcal/K mol) indicate that the adsorption process is spontaneous and endothermic.     

5-HT1D receptor inhibits renal sympathetic neurotransmission by nitric oxide pathway in anesthetized rats

Although serotonin has been shown to inhibit peripheral sympathetic outflow, serotonin regulation on renal sympathetic outflow has not yet been elucidated. This study investigated which 5-HT receptor subtypes are involved. Wistar rats were anesthetized (sodium pentobarbital; 60 mg/kg, i.p.), and prepared for in situ autoperfused rat kidney, which allows continuous measurement of systemic blood pressure (SBP), heart rate (HR) and renal perfusion pressure (PP). Electrical stimulation of renal sympathetic nerves resulted in frequency-dependent increases in PP (18.3 ± 1.0, 43.7 ± 2.7 and 66.7 ± 4.0 for 2, 4 and 6 Hz, respectively), without altering SBP or HR. 5-HT, 5-carboxamidotryptamine (5-HT_1/7 agonist) (0.00000125–0.1 μg/kg each) or l-694,247 (5-HT_1D agonist; 0.0125 μg/kg) i.a. bolus inhibited vasopressor responses by renal nerve electrical stimulation, unlike i.a. bolus of agonists α-methyl-5-HT (5-HT₂), 1-PBG (5-HT₃), cisapride (5-HT₄), AS-19 (5-HT₇), CGS-12066B (5-HT_1B) or 8-OH-DPAT (5-HT_1A) (0.0125 μg/kg each). The effect of l-694,247 did not affect the exogenous norepinephrine-induced vasoconstrictions, whereas was abolished by antagonist LY310762 (5-HT_1D; 1 mg/kg) or l-NAME (nitric oxide; 10 mg/kg), but not by indomethacin (COX_1/2; 2 mg/kg) or glibenclamide (ATP-dependent K⁺ channel; 20 mg/kg). These results suggest that 5-HT mechanism-induced inhibition of rat vasopressor renal sympathetic outflow is mainly mediated by prejunctional 5-HT_1D receptors via nitric oxide release.     

Serum antioxidant enzyme activities and oxidative stress parameters as possible biomarkers of exposure in veal calves illegally treated with dexamethasone

Low doses of the synthetic glucocorticoid dexamethasone (DEX) are often illegally used, alone or in association with steroids and β-agonists, to improve meat performances in cattle. As it is known that oestrogens and β-agonists may generate reactive oxygen species (ROS) and induce oxidative stress, the effects of illicit DEX protocols on the antioxidant status and oxidative stress parameters were measured in veal calves.Ten cross-bred male veal calves were given DEX (0.4 mg/day administered per os, for 23 days or 2 mg pro capite, injected intramuscularly on days 14 and 21 after the beginning of the oral DEX administration). Five further animals were used as controls. Blood samples were withdrawn before (T₀), and 4 (T₁), 10 (T₂), 14 (T₃), 21 (T₄) and 28 (T₅) days. Antioxidant enzyme activities (AOEs), the serum antioxidant capacity (SAC) and ROS were measured in sera.Calves orally treated showed a significant increase of both glutathione peroxidase isoforms (P < 0.05) and SAC (P < 0.05), too.Antioxidant enzymes have already been used as biomarkers (BMs) of response, measured in target or in surrogate tissues. Our results suggest glutathione peroxidase and SAC as possible BMs of illicit oral low-dose administration of DEX in cattle.     

Preparation and Characterization of Apo2L/TNF-Related Apoptosis-Inducing Ligand–Loaded Human Serum Albumin Nanoparticles with Improved Stability and Tumor Distribution

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has received considerable attention as a potential anticancer agent. However, recombinant Apo2L/TRAIL has several limitations, which include a weak pharmacokinetic profile, namely, a short biological half-life and rapid renal clearance, and an inability to form a homotrimeric structure. In this research, we attempted to develop a sustained release nanoparticle (NP) formulation that stabilizes Apo2L/TRAIL and preserves its antitumor activity. Apo2L/TRAIL-loaded human serum albumin (HSA) NPs were prepared using a desolvation technique optimized by particle size, zeta-potential, and entrapment efficiency. Apo2L/TRAIL in HSA-NPs continuously released over 24 h at 37°C in phosphate buffered saline and rat plasma condition, and the biological activity of Apo2L/TRAIL-HSA-NPs was preserved (IC₅₀ = 67.2 ng/mL versus Apo2L/TRAIL IC₅₀ = 55.4 ng/mL) with negligible activity loss. Furthermore, in vivo pharmacokinetic profiles and tumor distribution demonstrated the superiority of Apo2L/TRAIL-HSA-NPs over Apo2L/TRAIL. The circulating half-life period was significantly prolonged from 9.8 to 90.7 min (9.2-fold enhancement), and drug bioavailability was clearly enhanced on the basis of area under the curve analysis (2.7-fold). And tumor distribution of Apo2L/TRAIL-HSA-NPs was also increased at 1 h after injection, which was about 14-fold (1-h point) over that of Apo2L/TRAIL. These results show that Apo2L/TRAIL-loaded HSA-NPs should be considered as potential long-acting cancer agents.     

Carvedilol stability in paediatric oral liquid formulations

ObjectiveTwo carvedilol aqueous solutions and one carvedilol aqueous suspension for paediatric oral use (1 mg/ml) were studied to determine their stability.MethodAll samples were stored at 4, 25 and 40° C. Carvedilol content of each of the three formulations was tested using high performance liquid chromatography (HPLC). Each sample was analysed in triplicate at 0, 3, 7, 14, 28 and 56 days.ResultsCarvedilol stayed stable in the acidic aqueous solution at the three different temperatures during the 56 days of the study. In the alkaline solution, carvedilol was stable during 56 days at 25° C, but only 28 days at 4 and 40° C. In the aqueous suspension, carvedilol was stable during 56 days at 4 and 25° C, but only 28 days at 40° C.ConclusionsAll the formulations that were tested can be stored at 25° C for at least 56 days.     

In vivo preliminary investigations of the effects of the benzimidazole anthelmintic drug flubendazole on rat embryos and fetuses

Flubendazole, in a new formulation with high systemic bioavailability, has been proposed as a macrofilaricide against filarial diseases.To investigate embryotoxic activity, the new flubendazole formulation was administered orally to Sprague Dawley rats at 2, 3.46, 6.32 mg/kg/day on gestation day (GD) 9.5 and 10.5. Embryos/fetuses were evaluated on GD 11.5, 12.5 or 20.At 6.32 mg/kg/day (C_max = 0.801 μg/mL after single administration), flubendazole initially induced an arrest of embryonic development followed by a generalized cell death that led to 100% embryolethality by GD 12.5.At 3.46 mg/kg/day (C_max = 0.539 μg/mL after single administration), flubendazole markedly reduced embryonic development by GD 12.5 without causing cell death. On GD 20, 80% of fetuses showed malformations.At 2 mg/kg/day (C_max = 0.389 μg/mL after single administration), it did not interfere with rat embryofetal development.     

Lasting effect of preceding culture conditions on the susceptibility of C6 cells to peroxide-induced oxidative stress

The aim of the present study was to investigate the influence of the maintenance culture conditions on the competence of C6 rat glioma cells to cope with peroxide-induced oxidative stress. C6 cells were maintained either in Ham’s nutrient mixture F-10 supplemented with 15% horse serum and 2.5% foetal bovine serum (FBS) or in Dulbecco’s Modified Eagle’s Medium (DMEM) supplemented with 5% FBS. The differently cultured cells were exposed under identical conditions to hydrogen peroxide (H₂O₂) and cumene hydroperoxide (CHP) in serum-free DMEM. The cells maintained in high serum Ham’s F-10 medium (1) were less sensitive towards the cytotoxic action of both peroxides (EC₅₀-values: H₂O₂: 193 ± 23 μM; CHP: 94 ± 16 μM) than the cells maintained in low serum DMEM (EC₅₀-values: H₂O₂: 51 ± 10 μM; CHP: 27 ± 11 μM), (2) eliminated the peroxides (initial concentration: 100 μM) with higher rates (H₂O₂: 56 ± 5.5 vs. 32 ± 2.7, CHP: 32 ± 6 vs. 3.4 ± 0.6 nmol/min mg protein), (3) contained more glutathione (30 ± 2.5 vs. 14 ± 1.1 nmol/mg protein) and (4) owned a higher glutathione peroxidase activity (28 ± 3.4 vs. 9.5 ± 0.8 mU/mg protein). Glutathione reductase and catalase activities were not affected. These results demonstrate that the preceding culture conditions have a lasting effect on the susceptibility of cultured cells to oxidative stressors like peroxides. As cause for these differences a dissimilar supply of the cells with serum born antioxidants like selenium and α-tocopherol is discussed.     

Pre-clinical pharmacokinetics evaluation of an anticonvulsant candidate benzaldehyde semicarbazone free and included in β-cyclodextrin

The study aimed to investigate the pharmacokinetics and tissue distribution of the benzaldehyde semicarbazone (BS) a potential antiepileptic drug, administered as a free drug or complexed β-cyclodextrin (BS/β-CD). Free BS and BS/β-CD were administered to male Wistar rats as a 10 mg/kg intravenous bolus dose. For the oral route, 50 mg/kg and 100 mg/kg doses of the free drug and 50 mg/kg of the complex were administrated and plasma concentrations were determinated by a validated HPLC-UV method. Individual profiles were evaluated by non-compartmental and compartmental analysis using Excel^® and Scientist^®, respectively. Free BS plasma protein binding was 34 ± 5%. A one-compartmental model adequately described all the plasma profiles for both formulations. After intravenous (10 mg/kg) and oral (50 mg/kg) administration, the V_d (1.6 ± 0.5 and 2.2 ± 0.8 L/kg, respectively) and the Cl_tot (1.4 ± 0.5 and 1.8 ± 0.5 L/h kg, respectively) determinated for the BS/β-CD complex were higher than those obtained for the free drug, but the t_1/2 (0.8 ± 0.1 h) was similar (p < 0.05). The oral bioavailability of the BS/β-CD complex (～37%) was approximately 2-fold of the free BS (～20%). The higher drug brain penetration (2.8) after BS/β-CD dosing and the longer mean residence time in this organ, regardless of the administration route, reveals that the complex may be a potential drug carrier for the central nervous system delivery of BS.     

Alteration of pharmacokinetics of proguanil in healthy volunteers following concurrent administration of efavirenz

Efavirenz and proguanil are likely to be administered concurrently for the treatment of patients with HIV and malaria. The metabolism of proguanil is mediated principally by CYP2C19 while efavirenz is known to inhibit this enzyme. This study therefore investigated the effect of efavirenz on proguanil disposition. Fifteen healthy volunteers were each given 300 mg single oral doses of proguanil alone or with the 9th dose of efavirenz (400 mg daily for 11 days) in a crossover fashion. Blood samples were collected at pre-determined time intervals and analyzed for proguanil and its major metabolite, cycloguanil, using a validated HPLC method. Co-administration of proguanil and efavirenz resulted in significant increases (p < 0.05) in C_max, T_max, AUC_T and elimination half-life (T_1/2β) of proguanil compared with values for proguanil alone [C_max: 2.55 ± 0.24 mg/l vs 3.75 ± 0.48 mg/l; T_max: 2.80 ± 0.99 h vs 4.80 ± 0.99 h; AUC_T: 45.58 ± 12.75 mg h/l vs 97.00 ± 23.33 mg h/l; T_1/2β: 16.50 ± 4.55 h vs 23.24 ± 4.08 h]. Also, efavirenz caused a pronounced decrease in the AUC(metabolite)/AUC(unchanged drug) ratio of proguanil along with a significant decrease (p < 0.05) in C_max and AUC of the metabolite.These results indicate that efavirenz significantly alters the pharmacokinetics of proguanil. These suggest that the protection against malaria by proguanil may be decreased when the drug is co-administered with efavirenz and the antimalarial efficacy is dependent on cycloguanil plasma levels.     

Darunavir/ritonavir and raltegravir coadministered in routine clinical practice: Potential role for an unexpected drug interaction

The present study aimed to investigate potential drug interactions between darunavir and raltegravir in patients treated for HIV infection. We enrolled HIV-infected subjects on darunavir-containing regimens that underwent measurement of plasma darunavir trough concentration (12 ± 3 h after dosing). Two groups of patients were compared: those taking darunavir plus a nucleoside/nucleotide backbone (group 1) or a backbone + raltegravir (group 2). Interindividual pharmacokinetic variability was evaluated through the coefficient of variation (CV_inter).We obtained 156 plasma samples from 63 patients, of which 44 in group 1 and 19 in group 2. Overall, darunavir geometric mean concentration was 2.90 mg/L (95% CI 2.34–3.60) while ritonavir geometric mean concentration was 0.21 mg/L (95% CI 0.17–0.27). We observed a high inter-individual variability in darunavir (CV_inter 59%) and ritonavir (CV_inter 103%) plasma levels. Darunavir concentration correlated with concomitant ritonavir levels (r = 0.476, p < 0.001). Patients in group 1 had a higher darunavir geometric mean concentration than those in group 2 [3.44 mg/L (95% CI 2.79–4.23) versus 1.95 mg/L (95% CI 1.19–3.20), p = 0.017]. However, the proportion of subjects with concomitant HIV-RNA <50 copies/mL was higher in group 2 (78.9% versus 47.7%, p = 0.028). In a multivariable model, raltegravir co-administration was independently related to a lower darunavir concentration (mean difference ?0.25 log₁₀ mg/L, 95% CI ?0.46/?0.04, p = 0.020) after adjusting for time from last drug intake and concomitant drugs used.In conclusion, a potential drug interaction between darunavir and raltegravir was observed, although this did not seem virologically significant. For the distinct metabolic pathways of these drugs, its mechanism remains to be determined.     

Methodological agreement on the in vitro activity of ceftaroline against cefotaxime-susceptible and -resistant pneumococci

Ceftaroline reportedly has lower minimum inhibitory concentrations (MICs) than established cephalosporins for Streptococcus pneumoniae. We further evaluated this activity using 155 pneumococci chosen by serotype and cefotaxime MIC. MICs were determined by agar dilution on Mueller–Hinton agar and Iso-Sensitest agar and by Etest. Inhibition zones were measured for 5 μg and 30 μg ceftaroline discs using both CLSI/EUCAST and BSAC methodology. Ceftaroline was more active than cefotaxime, with MICs 2–8-fold lower for isolates with cefotaxime MICs of ≤1 mg/L and mostly in the range 0.125–0.5 mg/L for those with cefotaxime MICs of 2 mg/L to ≥16 mg/L. Twelve isolates belonging to serotypes 14 (n = 2), 19A (n = 6) and 19F (n = 4) were ceftaroline-resistant, with MICs of 0.5–1 mg/L. Essential agreement between MIC methods was excellent, with values on Iso-Sensitest agar and Mueller–Hinton agar identical ±1 doubling dilution in all cases, and with 154/155 values identical ±1 doubling dilution between agar dilution and Etest. Nevertheless, 5/11 isolates with agar dilution MICs of 0.5 mg/L (i.e. just resistant) ‘had’ MICs of 0.25 mg/L (just susceptible) by Etest. Inhibition zones also correlated with MICs, but discrimination around the breakpoint MICs was poor irrespective of method and disc type. In summary, the results confirm the good activity of ceftaroline against pneumococci, but susceptibility testing will present challenges in routine laboratories, with discs poorly discriminatory and with Etest prone to give susceptible results for isolates with MICs one doubling dilution above the breakpoint.     

Toxic effects of juvenile sablefish,Anoplopoma fimbria by ammonia exposure at different water temperature

Juvenile sablefish, Anoplopoma fimbria (mean length 17.1 ± 2.4 cm, and mean weight 75.6 ± 5.7 g) were used to evaluate toxic effects on antioxidant systems, immune responses, and stress indicators by ammonia exposure (0, 0.25, 0.75, and 1.25 mg/L) at different water temperature (12 and 17 °C) in 1 and 2 months. In antioxidant responses, superoxide dismutase (SOD) and catalase (CAT) were significantly increased by ammonia exposure, whereas glutathione (GSH) was decreased. In immune responses, lysozyme and phagocytosis activity were significantly increased by ammonia exposure. In stress indicators, plasma glucose, heat shock protein 70 (HSP 70), and cortisol were significantly increased. At high water temperature (17 °C), alterations by ammonia exposure were more distinctly. The results of this study indicated that ammonia exposure can induce toxic effects in the sablefish, and high water temperature can affect the ammonia exposure toxicity.     

Ceftolozane/tazobactam activity tested against Gram-negative bacterial isolates from hospitalised patients with pneumonia in US and European medical centres (2012)

During 2012, a total of 2968 isolates were consecutively collected from 59 medical centres in the USA and 15 European countries from hospitalised patients with pneumonia. Ceftolozane/tazobactam (tazobactam at a fixed concentration of 4 mg/L) and comparator agents were tested by reference methods, and MIC endpoints were interpreted by CLSI (2013) and EUCAST (2013) breakpoint criteria. Pseudomonas aeruginosa was the most common isolated pathogen (1019 strains; 34.3%), and ceftolozane/tazobactam was the most active β-lactam tested against P. aeruginosa (MIC_50/90, 0.5/4 mg/L; 94.1% inhibited at ≤8 mg/L). P. aeruginosa exhibited moderate susceptibility to meropenem (MIC_50/90, 0.5/>8 mg/L; 73.7% susceptible), ceftazidime (MIC_50/90, 2/>32 mg/L; 73.6% susceptible), cefepime (MIC_50/90, 4/>16 mg/L; 76.5% susceptible), piperacillin/tazobactam (MIC_50/90, 8/>64 mg/L; 69.5% susceptible), levofloxacin [MIC_50/90, 0.5/>4 mg/L; 69.9/61.0% susceptible (CLSI/EUCAST criteria)] and gentamicin (MIC_50/90, 2/>8 mg/L; 80.7% susceptible). Ceftolozane/tazobactam exhibited activity against many ceftazidime-non-susceptible, meropenem-non-susceptible and piperacillin/tazobactam-non-susceptible, multidrug-resistant (MDR) and extensively drug-resistant (XDR) P. aeruginosa isolates. Ceftolozane/tazobactam was active (MIC_50/90, 0.25/4 mg/L; 94.6% inhibited at ≤8 mg/L) against 1530 Enterobacteriaceae, including activity against many MDR and XDR strains. MDR and XDR prevalence varied widely between countries both for P. aeruginosa (24.1% MDR and 17.1% XDR overall) and Enterobacteriaceae (15.4% MDR and 2.7% XDR overall). All β-lactams had limited activity against Acinetobacter spp. and Stenotrophomonas maltophilia. Ceftolozane/tazobactam demonstrated greater in vitro activity than currently available cephalosporins, carbapenems and piperacillin/tazobactam when tested against P. aeruginosa. In addition, ceftolozane/tazobactam demonstrated greater activity than contemporary cephalosporins and piperacillin/tazobactam when tested against most Enterobacteriaceae.