Linking behavioural alterations with biomarkers responses in the European seabass Dicentrarchus labrax L. exposed to the organophosphate pesticide fenitrothion

The acute effects of the organophosphate insecticide fenitrothion on Dicentrarchus labrax juveniles were investigated through a bioassay using biomarkers and swimming behaviour as effect criteria. After 96 h of exposure to sub-lethal concentrations of fenitrothion, the swimming velocity and several biomarkers were individually determined, namely: brain acetylcholinesterase (AChE) activity; muscle cholinesterases (ChE), lactate dehydrogenase and isocitrate dehydrogenase activities; liver ethoxyresorufin-O-deethylase (EROD), glutathione S-transferases, glutathione peroxidase, glutathione reductase, catalase and superoxide dismutase (SOD) activities and lipid peroxidation levels (LPO). A significant decrease of the swimming velocity (LOEC = 2 mg l⁻¹), an inhibition of both AChE (LOEC = 0.06 mg l⁻¹) and ChE activities (LOEC = 0.03 mg l⁻¹), and a positive and significant correlation between the swimming velocity and AChE were found in exposed fish, suggesting an influence of the inhibition of these enzymes in the swimming velocity decrease. An increase of EROD activity (LOEC = 1 mg l⁻¹), indicating the involvement of this enzyme in fenitrothion biotransformation, and a negative and significant correlation between EROD activity and swimming velocity were also found, suggesting that the two findings may somehow be related. Furthermore, results show a significant induction of SOD (LOEC = 0.13 mg l⁻¹) without LPO increase, suggesting that the enzyme is preventing oxidative stress damage. No significant alterations were found in any of the other parameters tested. Thus, exposure of seabass to fenitrothion in the wild at concentrations similar to those tested here may have adverse consequences at population level as neurotransmission and swimming ability are essential for fish performance and survival.     

The physiological response and sub-cellular localization of lead and cadmium in Iris pseudacorus L.

The seedling development and physiological responses of Iris pseudacorus L. to Pb and Cd and their combination were studied for 28 days liquid culture and sub-cellular localization of Pb and Cd in the root tip cells treated with 2,070 mg L⁻¹ Pb and 1,000 mg L⁻¹Cd for 16 days sand culture was evaluated. Results showed that the dry weights (DWs) of shoots and roots of I. pseudacorus were significantly decreased at 500 mg L⁻¹Pb and 25 mg L⁻¹Cd + 500 mg L⁻¹Pb treatments and the root DWs under all treatments were significantly decreased in comparison with that of control. The concentrations of Chla in the leaves were decreased at all treatments, while, the concentrations of Chlb and total carotenoids were not significantly decreased under 25 mg L⁻¹Cd and 25 mg L⁻¹Cd + 500 mg L⁻¹Pb treatments. The MDA and proline concentrations and POD activities in the shoots and roots were increased under treatments of 500 mg L⁻¹Pb and 25 mg L⁻¹Cd + 500 mg L⁻¹Pb, but POD activities in the shoots and roots and MDA concentrations in the shoots were significantly decreased at 25 mg L⁻¹ Cd treatment. The results of sub-cellular localization of Pb and Cd showed that numerous Pb deposits were found on the inner surface of died cell walls in the cortex treated with 2,070 mg L⁻¹ Pb and Cd deposits were found in the cell wall treated with 1,000 mg L⁻¹ Cd. Pb and Cd deposits were not found in the cytoplasm. The results indicated that POD and proline showed strong beneficial properties against Pb and Cd stress and there were some mechanisms keeping most cells with normal activities in the plant from Pb toxicity by sacrificing a few cells that accumulated a large amount Pb. Sub-cellular localizations of Pb and Cd in the root tip cells of I. pseudacorus were little difference with the localizations in other species of Iris in the previous studies.     

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.     

Cytogenotoxicity of fifth-generation quaternary ammonium using three plant bioindicators

The investigation aimed to determine the cytogenotoxic effect of fifth-generation quaternary ammonium using three plant species as bioindicators. Bulbs of A. cepa and seeds of L. culinaris and P. sativum were exposed to different concentrations of fifth-generation quaternary ammonium and a control solution of distilled water for 72 h. The results showed that the A. cepa bioindicator presented the greatest reduction in root length at 50 mg L⁻¹ and no mitotic index at 40 and 50 mg L⁻¹, reaching 100% mitotic inhibition. Cell abnormalities were present among the three bioindicator species, where the highest index of micronuclei occurred at 50 mg L⁻¹, being A. cepa the bioindicator with the highest relative rate of abnormality (25.28%). It was concluded that fifth-generation quaternary ammonium, in all treatments, caused a cytogenotoxic effect on the apical meristematic cells of the three species, A. cepa was the most sensitive species.     

Toxicity of the amphoteric surfactant, cocamidopropyl betaine, to the marine macroalga, Ulva lactuca

The degradation of the synthetic, amphoteric surfactant, cocamidopropyl betaine (CAPB) and its toxicity to the marine macroalga, Ulva lactuca, has been evaluated using several different physiological test end-points over different periods of exposure up to 120 h. Droplet surface angle measurements revealed that, following a period of acclimation of about 24 h, CAPB began to degrade and that primary degradation was complete within 120 h. Effective quantum yield (∆F/F_m′) and relative growth rates (RGRs) were the most sensitive measures of phytotoxicity, with CAPB concentrations at and above 10 mg l⁻¹ eliciting irreversible, time-dependent and/or dose-dependent responses. Cell membrane damage, estimated from measurements of ion leakage, was detected only at a concentration of 40 mg l⁻¹ after 48 h of exposure to CAPB but by 120 h damage was evident at all measured concentrations above 10 mg l⁻¹. These observations suggest that both CAPB and its metabolites are intrinsically toxic to U. lactuca. The findings of this study are discussed in terms of the environmental consequences of applying CAPB to control harmful algal blooms.     

Can Lemna minor mitigate the effects of cadmium and nickel exposure in a Neotropical fish?

We aimed to evaluate if Lemna minor can mitigate the observed effects of cadmium (Cd) and nickel (Ni) exposure in Prochilodus lineatus. Fish were exposed for 96 h to 20 µg L^-1 of Cd, 1.5 mg L^-1 of Ni, or to a mixture of these two metals. In all tests, one group was exposed to the metals with duckweed on the water surface, and other group was exposed only to the metals, without plants. After each exposure, samples of P. lineatus tissues were collected to evaluate multiple biomarkers. Duckweed prevented bioaccumulation in some fish tissues and attenuated changes in acetylcholinesterase activity, increases in erythrocytic nuclear abnormality frequency, and hyperglycemia. However, the changes in plasma ion concentrations, reduction in activity of ion transport enzymes, and histological damage were not mitigated. Therefore, we concluded that L. minor partially attenuates the effects caused by Cd and Ni exposure.     

Antimicrobial activity of isolate HL-12 against Clavibacter michiganensis subsp. michiganensis in the presence of cadmium

An actinomycete, strain HL-12, that was isolated from a farmland on the Huajiachi campus of Zhejiang University was capable of inhibiting the growth of Clavibacter michiganensis subsp. michiganensis (Cmm) and was identified as a member of Streptomyces. Its antimicrobial activity against Cmm was measured using the agar plate sensitivity method in pure culture and evaluated by the inhibition ratio of Cmm in soil. The inhibitory activity of strain HL-12 against Cmm following exposure to low concentrations of Cd was greater than the inhibitory activity following exposure to high concentrations of Cd both in liquid culture and in soil. A stronger inhibition was also seen following a 24 h preculture in the presence of Cd in liquid culture. The growth of Cmm in soil was stimulated at low concentrations of Cd (<5.0 mg Cd kg⁻¹ dry soil) but inhibited when cultured in high concentrations of Cd (5.0 and 10.0 mg Cd kg⁻¹ dry soil). A higher inhibition ratio of strain HL-12 against Cmm, which was over 40% after soil incubation for 2 weeks, was observed following exposure to low concentrations of Cd (<5.0 mg Cd kg⁻¹ dry soil).     

Acute and chronic effects of sodium and potassium on the tropical freshwater cladoceran <Emphasis Type="Italic">Pseudosida ramosa</Emphasis>

In this study, the toxicities of sodium and potassium to the tropical freshwater cladoceran Pseudosida ramosa were assessed. Acute toxicity tests on this species showed that the 48-h LC₅₀ of Na⁺ was 556 mg l⁻¹, while that of K⁺ was 17.7 mg l⁻¹. Long-term exposure of female P. ramosa to sodium reduced the total number of survivors from 10 to 6 at a concentration of 249 mg l⁻¹, 21-day fecundity from 20.4 to 14.3 eggs female⁻¹ at concentrations ranging from 72 to 249 mg l⁻¹, 21-day fertility from 20.1 to 6.5 neonates female⁻¹ at concentrations ranging from 25 to 249 mg l⁻¹. Furthermore, fecundity of each brood from the second to the fifth was significantly lower at 249 mg l⁻¹ and fertility of each brood from the first to the fifth at concentrations ranging from 25 to 249 mg l⁻¹. A significant decrease in fertility was associated with an increase in the number of aborted eggs. Long-term exposure to potassium decreased the 21-day fecundity of P. ramosa from 14.2 to 10.8 eggs female⁻¹ at a concentration of 11 mg l⁻¹ and fertility (fourth brood only) at 6.2 and 11 mg l⁻¹. Tropical reservoirs located near areas where the soil is overloaded with fertilizers and ferti-irrigation with vinasse already show concentrations of Na⁺ and K⁺ very close to those producing sub-lethal long-term effects on P. ramosa. A possible consequence is that organisms of the aquatic biota cannot adapt and freshwater taxa may become locally extinct, transferring dominance to salt-tolerant taxa.     

A study of genotoxicity and oxidative stress induced by mercuric chloride in the marine polychaete Perinereis aibuhitensis

The marine polychaete worm Perinereis aibuhitensis was used to study the genotoxic effects of mercuric chloride by means of the comet assay and micronucleus (MN) test. P. aibuhitensis was subjected in vivo to two different concentrations of mercuric chloride (0.05 mg L⁻¹ and 0.5 mg L⁻¹) for 96 h. The comet assay of coelomocytes demonstrated that TailDNA% values increased with extended exposure to or increased concentrations of HgCl₂ (p < 0.01). The frequency of MNs was the highest in the treatment with 96 h of exposure at all concentrations (p < 0.01). The genotoxic effect of HgCl₂ was both dose- and time-dependent in exposed P. aibuhitensis. The activities of the antioxidant enzymes, superoxide dismutase (SOD) and glutathione peroxidases (GPx) were also estimated. Significant variations in antioxidant enzyme activities depended on the sampling time and the concentrations of mercuric chloride. Compared with the control, the activities of the antioxidant enzymes (SOD and GPx) were elevated at the lower concentration of mercuric chloride (0.05 mg L⁻¹) (p < 0.05) for shorter exposure periods (24 h and 72 h). At the higher concentration of mercury (0.5 mg L⁻¹), the activities of GPx and SOD were inhibited; no variation was observed. These results proved that the use of the comet assay and MN test in coelomocytes of P. aibuhitensis is appropriate for determining the levels of DNA damage and that P. aibuhitensis is a species that is sensitive to mercury pollutants. This species may be considered a suitable candidate for monitoring marine heavy metal pollution.     

In vitro endocrine disruption and TCDD-like effects of three novel brominated flame retardants: TBPH,TBB, & TBCO

The novel brominated flame retardants (NBFRs), 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (TBB), Bis(2-ethylhexyl)-2,3,4,5-tetrabromophtalate (TBPH), and 1,2,5,6-tetrabromocyclooctane (TBCO) are components of flame retardant mixtures including Firemaster 550 and Saytex BC-48. Despite the detection of these NBFRs in environmental and biotic matrices, studies regarding their toxicological effects are poorly represented in the literature. The present study examined endocrine disruption by these three NBFRs using the yeast YES/YAS reporter assay and the mammalian H295R steroidogenesis assay. Activation of the aryl hydrocarbon receptor (AhR) was also assessed using the H4IIE reporter assay. The NBFRs produced no TCDD-like effects in the H4IIE assay or agonistic effects in the YES/YAS assays. TBB produced a maximal antiestrogenic effect of 62% at 0.5 mg L⁻¹ in the YES assay while TBPH and TBCO produced maximal antiandrogenic effects of 74% and 59% at 300 mg L⁻¹ and 1500 mg L⁻¹, respectively, in the YAS assay. Significant effects were also observed in the H295R assay. At 0.05 mg L⁻¹, 15 mg L⁻¹, and 15 mg L⁻¹ TBB, TBPH, and TBCO exposures, respectively resulted in a 2.8-fold, 5.4-fold, and 3.3-fold increase in concentrations of E2. This is one of the first studies to demonstrate the in vitro endocrine disrupting potentials of TBB, TBPH, and TBCO.     

Embryo–fetal toxicity assessment of vonoprazan in rats and rabbits

Vonoprazan is a new potassium‐competitive acid blocker to treat acid‐related diseases. However, its safety during pregnancy is unclear. The aim of the study was to investigate the potential reproductive toxicity on the embryo–fetal development of vonoprazan. Vonoprazan acetate was administered by intravenous injection to pregnant rats (0, 2, 6 and 20 mg kg^–1 day^–1) and rabbits (0, 1.2, 3.6 and 12 mg kg^–1 day^–1) during the organogenetic period (gestation day 6–15 [rats] and 6–18 [rabbits]). Maternal reproductive endpoints were evaluated, together with effects on fetal growth and morphological development. In rats, no treatment‐related effects were found in the highest dose group (20 mg kg^–1) and the maternal plasma exposure was ≥50‐fold the expected clinical human exposure. However, in rabbits, dose‐related clinical signs (soft or liquid feces) occurred in the 12 mg kg^–1 group, which was regarded as a maternal toxicity. Besides, decreased maternal weight gain also was considered as a minimal maternal toxicity. At 12 mg kg^–1, delayed fetal ossification was found as evidence of embryo–fetal growth retardation, which was related to decreased fetal and placental weights. There was no maternal and developmental toxicity in the 1.2 and 3.6 mg kg^–1 groups. Thus, the no‐observed‐adverse‐effect levels of vonoprazan acetate in rabbits are considered 3.6 mg kg^–1 day^–1, which produced plasma exposure that was about 18‐fold human clinical exposure.     

Growth response of the duckweed <Emphasis Type="Italic">Lemna gibba</Emphasis> L. to copper and nickel phytoaccumulation

To assess the tolerance and phytoaccumulation ability of the duckweed Lemna gibba L. to copper (Cu) and nickel (Ni), the plants were exposed to different concentrations of Cu and Ni (0.1–2.0 mg/l) under laboratory conditions. The results showed that Cu and Ni were tolerated by L. gibba at concentrations ≤0.3 and ≤0.5 mg/l, respectively. However, plant growth decreased by 50% (I₅₀) when the medium contained 0.45 mg Cu/l or 0.75 mg Ni/l. The observed LCI (lowest concentration causing complete inhibition) were 0.5 and 1.0 mg/l respectively in the presence of Cu and Ni. Results from metal analysis in plant biomass revealed a high accumulation of Cu (1.5 mg g⁻¹ DW), a low accumulation of Ni (0.5 mg g⁻¹ DW) within the plants and a corresponding decrease of metals in the water. The removal percentage of Cu was about 60–80%. We conclude that the duckweed L. gibba L. showed a higher accumulation potential for Cu from polluted water than Ni after 4 days of exposure.     

Tissue-specific accumulation of cadmium and its effects on antioxidative responses in Japanese flounder juveniles

This study investigated the accumulation of cadmium (0-8 mg Cd L⁻¹) and its toxicological effects on oxidative stress biomarkers in different tissues of Japanese flounder juveniles. Following Cd exposure for 28 d, accumulation of Cd in fish was dose-dependent and tissue-specific, with the greatest accumulation in the liver, followed by the kidney, gill, and muscle. Although the gill and liver mounted active antioxidant responses at ≥4 mg L⁻¹ Cd including a decrease in glutathione level and GST and GPx activities, the antioxidant response failed to prevent lipid peroxidation induction in these organs. In the kidney, increased GPx and GST activities and decreased SOD activity were observed in fish exposed to high Cd concentrations, but LPO levels did not significantly differ among the exposure concentrations. The gill was most sensitive to oxidative damage, followed by the liver; the kidney was the least affected tissue.     

Differential developmental toxicities of di‐n‐hexyl phthalate and dicyclohexyl phthalate administered orally to rats

The objective of this study was to evaluate the developmental toxic potential of di‐n‐hexyl phthalate (DnHP) and dicyclohexyl phthalate (DCHP) in rats. Pregnant Sprague–Dawley rats were exposed to DnHP or DCHP at doses of 0 (olive oil), 250, 500 and 750 mg kg^–1 per day, by gavage, on gestational days (GD) 6–20. Maternal food consumption and body weight gain were significantly reduced at 750 mg kg^–1 per day of DnHP and at the two high doses of DCHP. Slight changes in liver weight associated with peroxisomal enzyme induction were seen in dams treated with DnHP or DCHP. DnHP caused dose‐related developmental toxic effects, including marked embryo mortality at 750 mg kg^–1 per day, and presence of malformations (mainly cleft palate, eye defects and axial skeleton abnormalities) and significant decreases in fetal weight at 500 and 750 mg kg^–1 per day. Significant delay of ossification and increase in the incidence of skeletal variants (e.g. supernumerary lumbar ribs) also appeared at 250 mg kg^–1 per day. DCHP produced fetal growth retardation at 750 mg kg^–1 per day, as evidenced by significant reduction of fetal weight. DnHP and DCHP induced a significant and dose‐related decrease in the anogenital distance of male fetuses at all doses, and there was a significant increase in the incidence of male fetuses with undescended testis at 500 and 750 mg kg^–1 per day of DnHP. In conclusion, DnHP showed clear embryolethality and teratogenicity, but not DCHP. There was evidence that both phthalates could alter the development of the male reproductive system after in utero exposure, DnHP being much more potent than DCHP. Copyright © 2009 John Wiley & Sons, Ltd.     

Boosting photosynthetic biogas upgrading via carbon-coated zero-valent iron nanoparticle addition: A pilot proof of concept study

The effect of carbon-coated zero-valent iron nanoparticles (NPs) on the upgrading of biogas based on bacterial-algal symbiosis was assessed in an indoor pilot scale algal open pond interconnected to a biogas purification column. The addition of NPs at 70 mg L^?1 stimulated photosynthetic activity, resulting in an enhanced concentration of biomass from 1.56 to 3.26 g VSS L^?1. The presence of NPs in the culture broth increased CO₂ removal from 86% to 92% at low IC concentrations (≤600 mg L^?1) and a decrease in the content of O₂ and N₂ in the upgraded biomethane. This entailed an increase of the CH₄ concentration in the upgraded biomethane from 83% to 91%. However, the higher biomass productivity resulted in a gradual depletion of the IC concentration concomitant with a reduction of the buffer capacity which requires a further optimization in the operational conditions to maintain the beneficial effects of NPs.     

Biological responses of maize (Zea mays) plants exposed to chlorobenzenes. Case study of monochloro-, 1,4-dichloro- and 1,2,4-trichloro-benzenes

A 7-day-exposure time experiment was designed to investigate the phytotoxicity of chlorobenzenes (CBs) on Zea mays seedlings, focusing on the growth and generation of oxidative stress. Significant growth inhibition (based on biomass gain) was observed for exposure to monochlorobenzene (MCB), dichlorobenzene (DCB) and trichlorobenzene (TCB) concentrations higher than 10 mg l⁻¹. It would seem that CBs inhibit cell division, since the mitotic index decreased for roots exposed to DCB at 80 mg l⁻¹ dose (8%) and to all the TCB concentrations tested (20% inhibition). CBs exposure resulting in an increase in the oxidative stress response in maize seedlings [reactive oxygen species like H₂O₂, antioxidant enzymes (POD, GR), lipid peroxidation] correlated to the compound’s degree of chlorination, where damage increasing with the number of chlorine atoms (MCB < DCB < TCB). This biological response was also dependent on the dose-exposure. Z. mays exposed to CBs at concentrations <10 mg l⁻¹ did not induce sufficient oxidative damage to cause root cell death. Therefore, CBs at current environmental concentrations are unlikely to produce evident phytotoxic effects on Z. mays seedlings.     

Maternal and fetal zidovudine pharmacokinetics during pregnancy and labour: too high dose infused at labour?

Aims

The main goal of the study was to describe the pharmacokinetics of maternal zidovudine (ZDV) administration during pregnancy and labour and to evaluate their impact on fetal concentrations and exposures.

Methods

A total of 195 HIV-infected pregnant and non-pregnant women aged 16–59 years were included and 273 maternal and 79 cord blood ZDV concentrations were collected. A population pharmacokinetic model was developed to describe ZDV concentrations as a function of time in the mother and the fetus. Fetal exposures resulting from maternal oral administration and infusion were estimated and compared with therapeutic exposures (3–5 mg l⁻¹ h) and to exposure providing higher risk of toxicity (>8.4 mg l⁻¹ h). Different protocols for ZDV administration during labour were simulated.

Results

The median fetal exposure and the percentage of children with values above 8.4 mg l⁻¹ h were 3.20 mg l⁻¹ h and 0% after maternal oral administration, respectively, and 9.71 mg l⁻¹ h and 51% after maternal infusion during labour. Two options were considered to reduce fetal exposure during labour: (i) maternal infusion rates could be 1 mg kg⁻¹ h⁻¹ during 1 h followed by 0.5 mg kg⁻¹ h⁻¹ and (ii) the mother could only take oral ZDV every 5 h from start of labour until delivery with her neonate having their first ZDV dose as soon as possible after birth.

Conclusions

Zidovudine exposures are very important during labour and during the first days of a neonate''s life. Maternal ZDV dose should be reduced in addition to the neonate doses reduction already proposed.     

Multi-biomarker approach and IBR index to evaluate the effects of bisphenol A on embryonic stages of zebrafish (Danio rerio)

This study assessed the effects of Bisphenol A in embryonic stages of zebrafish, applying an IBR multi-biomarker approach that included alterations in growth and oxidative status and relates it with the expression of Nrf1, Nrf2, Wnt3a, Wnt8a, COX-2, Qdpra, and DKK1 genes. For this purpose, we exposed zebrafish embryos to eight environmentally relevant concentrations of BPA (220, 380, 540, 700, 860, 1180, 1340, and 1500 ng L⁻¹) until 96 h post-fertilization. Our results show that BPA induces several malformations in embryos (developmental delay, hypopigmentation, tail malformations, and on), leading to their death. The LC₅₀, EC₅₀ of malformations, and teratogenic index (TI) were 1234.60 ng L⁻¹, 987.77 ng L⁻¹, and 1.25, respectively; thus, this emerging contaminant is teratogenic. Regarding oxidative stress and gene expression, we demonstrated BPA altered oxidative status and the gene expression in embryos of Danio rerio.     

Dose- and time-dependence of L-NAME neuroprotection in transient focal cerebral ischaemia in rats

1. In this study the effect of the dose and administration time of N^G-nitro-L-arginine methyl ester (L-NAME), an NO-synthase inhibitor, in a model of transient focal cerebral ischaemia in rats was investigated.
2. Two injections of L-NAME were given, of 1, 3 and 10 mg kg⁻¹, 5 min and 3 h after the onset of ischaemia. None of the doses gave any striatal neuroprotection, but 1 and 3 mg kg⁻¹ L-NAME reduced the infarcted volume in the cortex (by 26%, P<0.01 for 1 mg kg⁻¹ and 21%, P<0.05 for 3 mg kg⁻¹), whereas 10 mg kg⁻¹ had no neuroprotective effect.
3. Single injections of L-NAME 1 mg kg⁻¹, given 5 min or 3 h after ischaemia onset, had similar neuroprotective effects on the cortical infarction as did the repeated injections.
4. L-NAME 1 mg kg⁻¹ given 3, 6 or 9 h after ischaemia induction reduced the cortical infarct volume by 19% (P<0.01) when given 3 h after ischaemia, by 21% (P<0.01) when given at 6 h, and by 16% (P<0.5) when given at 9 h, but had no neuroprotective activity when given 12 h after ischaemia.
5. Thus a low dose of L-NAME is neuroprotective in a model of transient focal ischaemia, with a wide therapeutic window, much larger than that found for MK-801.

     

Carbamazepine sorption characteristics onto bentonite clay: Box-Behnken process design

A comprehensive study has been hold as a function of ionic strength, pH, equilibrium (Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherm models), kinetic (pseudo-first order, pseudo-second order and intraparticular kinetic models) and thermodynamic for the removal of carbamazepine (CBZ) from its aqueous solutions onto bentonite. A statistical experimental design method (Box-Behnken) has been applied for the optimal adsorption conditions (0.089 g resin/10.31 mL solution under 144 rpm mixing speed of shaking bath) in order to achieve the maximum yield (≈80% removal). Partition coefficient (PC) was also employed for the evaluation of the bentonite clay's performance. The equilibrium time was determined as 15 min depending on the kinetic study, where the maximum adsorption capacity (2.3550 mg g^-1) and PC (0.0684 mg g^-1 μM^-1) were achieved for an initial CBZ concentration of ≈30 mg L^-1. Effects of pH (3, 5, 7, 9 and 11) and ions (chloride, fluoride and lead) on the CBZ adsorption have been explored. The acidic media (pH ~ 3) enhanced the removal, while ionic strength caused to drop the adsorption from 22 to 51% depending on the ion and its concentration (0.17, 0.86 and 1.71 mol L^-1 for chloride; 0.24, 0.48 and 0.95 mol L^-1 for floride; 0.03, 0.15 and 0.30 mol L^-1 for lead) in the solution. Finally, the nature of the adsorption process for the CBZ removal onto bentonite has been detected to be a non-spontaneous and endothermic, having a tendency to an irregular structure.