According to fiber characteristics of length and diameter (aspect

According to fiber characteristics of length and diameter (aspect ratio),

fibers with high aspect ratio (10-15 nm diameter and containing two different length distributions of 545 +/- 230 and 10451 +/- 8422 nm length) are more toxic to lung than low-aspect-ratio fibers (10-15 nm diameter and length of 192 nm). It was thus of interest to investigate the effects of multiwall carbon nanotubes (MWCNT) on selleckchem the viability of normal human embryonic lung cells (WI-38) using trypan blue dye exclusion, the tetrazolium salt WST-1 (4-[3-(4-iodophenyl)-2-(4-nitrophenyl)-2H-5-tetrazolio]-1,3-benzene disulfonate) assay, and lactate dehydrogenase (LDH) activity assay. MWCNT produced cell growth inhibition and death at 12.5-200 g/ml after 24-72 h of incubation. In addition, high-aspect-ratio MWCNT were found to produce Cl-amidine purchase higher incidence of cytotoxicity than low-aspect-ratio fibers at 50-200 g/ml concentration. In the presence of less than 10% trace element content such as iron in MWCNT, the trace element exerted no marked effect on cellular viability. Data indicate that MWCNT inhibited cell proliferation and triggered cell death, and it would appear that the MWCNT fiber characteristics rather than impurities play a predominant role in the observed the cytotoxicity attributed to MWCNT.”
“Marijuana discontinuation

has been recently reported to be anxiogenic in humans, which may predict relapse. Limited animal research has been carried out to model this withdrawal-associated negative affect. The current study sought to investigate the potential anxiety-like effects of cannabinoid withdrawal in mice. Male ICR mice were injected s.c. with delta9-tetrahydrocannabinol (THC) at 10 mg/kg or vehicle once daily for 10 days. To precipitate withdrawal, the cannabinoid CBI antagonist SR141716 (0.3, 1.0, or 3.0 mg/kg) or vehicle was administrated i.p. 4 h following the last THC or vehicle treatment. Thirty minutes later, mice were tested on the elevated plus-maze (EPM) for 5 min. SR141716 did not significantly change EPM behaviors in vehicle-treated mice. In contrast, SR141716 precipitated a reduction in exploration of the open arms of EPM in mice repeatedly

treated with THC vs vehicle. At 3.0 mg/kg, SR141716 significantly reduced % open arm entries of the total arm entries, % open arm time of total time in arms, and the absolute time spent in open arms. No significant differences in the number of closed or total arm entries were observed, indicating that the behavioral changes were not due to altered motor activity. Collectively, the present results constitute the first evidence that cannabinoid withdrawal produces anxiety-like effects in mice. This animal model may help to identify the mechanisms that contribute to adaptations in the neuronal circuitry of the brain that are expressed as emotional symptoms of cannabinoid withdrawal. (C) 2010 Elsevier Ireland Ltd. All rights reserved.

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