Reproductive Toxicity of Sulfamethazine in Swiss CD-1 Mice during Continuous Breeding

Sulfamethazine (SMZ) was evaluated for reproductive toxicityin Swiss CD-1 mice using a continuous breeding protocol. SMZwas administered in the diet at 0, 0.25, 0.5, or 1% (w/w), whichrepresented an average daily intake of 0, 313, 625, or 1250mg SMZ/kg/day, respectively. Exposure of F0 male and femalemice to 1% SMZ for 126 days resulted in a significant decreasein the mean number of live pups per litter and the number oflitters produced (task 2); the percentage pups born alive to1% SMZ females showed a nonsignificant decrease versus controlfemales. The effects on fertility were rapid to onset (1 to4 weeks) and cumulative in nature. F0 male and female body weightswere slightly depressed from 3 weeks to the end of the study.The crossover mating trial (task 3) revealed that the adverseeffect on ferility involved both treated partners in that littersize decreased when either 1% SMZ males were bred to controlfemales or 1% SMZ females were mated with control males. Afterapproximately 155 days of exposure of F0 mice to 1% SMZ, theterminal body weight of 1% SMZ females was significantly decreasedand that of 1% SMZ males showed a nonsignificant decrease. Inaddition, the liver weight to body weight ratio of the maleswas increased. Further, the prostate and seminal vesicle weightto body weight ratios were decreased in 1% SMZ males relativeto control males. No treatment-related gross or histopathologicallesions were noted for the pituitary or reproductive organsof either sex. Sperm assessment indicated no significant differencein the epididymal sperm concentration or percentage motile orabnormal sperm. In conclusion, SMZ was found to be a reproductivetoxicant in the male and female Swiss CD-1 mouse, albeit atrelatively high dietary intake (1250 mg/kg/day), and in thepresence of mild systemic toxicity.     

PCR with arbitrary primers: approach with care

New techniques have recently been described that employ the polymerase chain reaction (PCR) to amplify arbitrary regions of a genome using a single primer. The techniques reveal polymorphisms in insect taxa that lack allozyme variation and, for the first time, permit genetic polymorphisms to be rapidly analysed in small arthropods (e.g. mites, endoparasitic wasps). The methods have been used in identification of sub-species and cryptic species, and have applications in population genetics and genetic fingerprinting. They are fairly inexpensive, do not require the use of radioactivity, are relatively simple to learn and can easily be adapted to most laboratories. However, their application is not without technical problems and practical limitations. The purpose of this note is to indicate the critical factors to consider before launching into their use. We chiefly emphasize that most polymorphisms revealed by these methods segregate as dominant markers. Furthermore, application of these techniques requires extensive standardization and may not prove to be reproducible among various laboratories especially those employing different types of thermal cyclers. There are some unique features of these polymorphisms to consider when using them in genetic fingerprinting. In addition, because the techniques amplify arbitrary regions of genomes, similarly sized fragments amplified between two species may not be homologous. This argument and empirical observations suggest that PCR with arbitrary primers will have limited application in molecular systematics above the intraspecific level.     

A novel computerized functional assessment for human immunodeficiency virus-associated neurocognitive disorder

Human immunodeficiency virus (HIV)-associated neurocognitive disorder (HAND) is present in 30–60 % of HIV-positive (HIV+) individuals and can be assessed by neuropsychological testing and level of functional impairment. HAND diagnosis therefore requires accurate assessment of functional impairment. The Computer Assessment of Mild Cognitive Impairment (CAMCI) is a computer-based screening tool that includes performance-based measures of functional impairment. We sought to evaluate the CAMCI as a functional assessment tool in HAND. One hundred fourteen HIV+ patients and 38 HIV-negative (HIV?) patients underwent neuropsychological and CAMCI testing. Cognitive status for HIV+ subjects was classified using the Frascati criteria. HIV+ subjects grouped together and classified by cognitive impairment performed worse than HIV? subjects on several of the CAMCI tasks, including following directions to the supermarket (p?=?0.05, p?=?0.03), recalling which items to purchase (p?=?0.01, p?=?0.02), and remembering to stop at a supermarket (p?<?0.01, p?=?0.01) and the post office (p?<?0.01, p?=?0.03). After controlling for hepatitis C status and depression symptomatology, the tasks “following directions to the supermarket” and the “recalling which items to purchase” were no longer significant. The “remembering to run two separate errands” tasks retained their significance (p?<?0.01 for both tasks). A subset of the CAMCI tasks therefore successfully differentiated HIV+ patients from HIV? individuals. Differences in hepatitis C status and depression symptomatology could account for some of the function assessment differences in the CAMCI. These results suggest the CAMCI could be a useful objective performance-based functional assessment in patients with HIV.