Although evidence indicates that exposure to organophosphorus (OP) pesticides induces neurobehavioral disorders, little is known about the effects of OP on aggressive behaviour. Our study investigated the effects of repeated exposure to an OP pesticide, methamidophos, on the isolation-induced aggressive behaviour in mice. Forty seven male mice were individually housed for a month. Socially isolated animals were then confronted with a standard non-isolated opponent for 15 minutes (pre-treatment trial), and the latency and frequency of aggressive and general exploratory behaviours were recorded. Based on the presence of attack behaviour in the pre-treatment trial, mice were classified as isolation-induced aggressive and non-aggressive. All mice were then treated for seven days with methamidophos (3.5 mg/kg/day, n=22, ip) or saline (1 mL/kg/day, control group, n=25, ip) and a second trial performed. Repeated exposure to methamidophos induced attack behaviour in non-aggressive mice. The treatment with methamidophos also decreased plasma butyrylcholinesterase and brain acetylcholinesterase activity. These results suggest that methamidophos has a pro-aggressive effect on socially isolated mice.
We compared bacillary loads after splitting sputum specimens by chemical (N-acetyl-L-cysteine [NALC]) and mechanical homogenization by vortexing with sterile glass beads. NALC and vortexing with glass beads were equally effective at homogenizing sputum specimens, resulting in an equal distribution of tubercle bacilli in the aliquots.
Interest in and development of new diagnostic tools for tuberculosis (TB) have increased dramatically over the past decade. Surprisingly little attention has been paid to the optimal method to compare diagnostic tests using sputum specimens, the specimens most commonly collected for TB diagnosis globally. As part of a study to compare two methods of microscopy to detect acid-fast bacilli (AFB), we aimed to determine an optimal method to split sputum specimens evenly. We preferred this approach to that of comparing specimens obtained on different days or at different times due to the known variability in bacillary load, most often reflected in the AFB semiquantification, among specimens obtained at different points in time. The macroscopic appearance of sputum samples may vary considerably, and many laboratories use a time-honored descriptive classification of mucoid, mucopurulent, purulent, and bloody (5). Purulent sputum specimens have long been recognized as having a higher likelihood of being positive for AFB on microscopy (5). Accordingly, laboratory personnel have been instructed to sample the most purulent portion of the specimens to maximize recovery of tubercle bacilli (4). Mycobacteria may also clump within specimens (2), which could in turn result in an unequal distribution of bacilli upon splitting. Given these recognized sources of variability both between and within sputum specimens, we aimed to use a method that would most evenly split the specimen based on quantitative culture. We compared splitting after homogenization by chemical mucolysis versus that by mechanical homogenization by vortexing with sterile glass beads.The protocol was approved by the institutional review board. The study was conducted from August 2007 to May 2009. A total of 103 adults (18 to 65 years) with 2ϩ (42%) or 3ϩ (58%) acid-fast bacillus smear-positive pulmonary TB were enrolled. These diagnoses were confirmed by the cultivation of Mycobacterium tuberculosis. In order to evaluate the efficacy of chemical and mechanical procedures to digest sputum, native sputum samples were subjected to one of the following procedures (Fig. 1). In procedure 1, 43 samples were treated with N-acetyl-L-cysteine (NALC) (50 mg/ml) in a volume equivalent to 10% of the total sample volume for 15 min at room temperature, homogenized by vortexing, split into two equal aliquots and cultured on selective Middlebrook 7H11 agar plates as described previously (3). In procedure 2, 42 samples were vigorously vortexed with sterile glass beads (4 mm in diameter) three times, 1 min each, split into two equal aliquots, treated with NALC, and cultured on selective Middlebrook 7H11 agar plates. In procedure 3, 18 samples were hom...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.