Correlation of regenerable opsin with rod ERG signal in Rpe65-/- mice during development and aging

PURPOSE: RPE65 has been shown to be essential for the production of 11-cis retinal by the retinal pigment epithelium. Mutations in RPE65 are known to be associated with severe forms of early-onset retinal dystrophy. This project was designed to determine the amount of regenerable opsin in Rpe65-/- mice during development and aging, and to examine the function of this rhodopsin by electroretinography (ERG). METHODS: Young and aged Rpe65-/- and wild-type (WT) mice were dark adapted. Endogenous rhodopsin and regenerable opsin were measured using absorption-difference spectrophotometry. Photoreceptor function was assessed with scotopic single-flash ERGs and photoreceptors were counted in histologic sections. Opsin's primary structure was analyzed by mass-spectrometric mapping. RESULTS: Unlike WT mice, amounts of regenerable opsin in Rpe65-/- mice decreased significantly with age, which correlated with a decrease in the number of photoreceptors and a decline in ERG amplitudes. Opsin structure, however, did not change. No endogenous levels of rhodopsin were measurable in the Rpe65-/- mice (detection limit: 0.225 pmol). 11-cis Retinal injections resulted in the regeneration of similar amounts of rhodopsin and improved rod function in a comparable way, irrespective of age. CONCLUSIONS: In the aged Rpe65-/- mouse, opsin levels decrease because of the loss of photoreceptors. The remaining opsin is structurally intact, and the components of the phototransduction cascade and the retinal circuitry remain functional, despite the absence of normal photoreceptor activity.     

An evaluation of rapid point-of-collection oral fluid drug-testing devices

New technology is currently being marketed to rapidly test oral fluids for drugs of abuse at the point of collection (POC). There are no nationally accepted standards or cutoff concentrations for detecting drugs in oral fluids and for most analytes there are significant differences in cutoff concentrations across devices. Four devices were evaluated (OralLab), RapiScan, Drugwipe, and SalivaScreen) for their ability to meet manufacturers claims, and proposed federal standards for criminal justice and workplace programs. Human oral fluid fortified with known quantities of drug [drug(s) or metabolite(s)] was used to test these devices. Overall, the performance of these rapid POC oral fluid drug-testing devices was quite variable. Some devices performed well for the analysis of some drug classes but poorly for others. In general, most devices performed well for the detection of methamphetamine and opiates, but all performed poorly for the detection of cannabinoids. The ability to accurately and reliably detect cocaine and amphetamine was dependent on the individual device.     

Ethnicity in child maltreatment research: a content analysis

The present study represents a content analysis of 1,133 articles published between 1977 and 1998 in Child Abuse and Neglect, Child Maltreatment, and Journal of Child Sexual Abuse was performed. Although there were indications of increased attention to ethnicity in child maltreatment research published between 1977 and 1998, the improvements were modest. Of the 1,133 articles examined, 6.7% focused on ethnicity. The percentage of studies that provided information on the ethnic composition of samples increased across time; however, only half of the studies published in the most recent years examined (1995-1998) reported information on the ethnicity of the participants. Although the percentage of articles that used ethnicity in analyses or as a control variable increased across time, three quarters of the articles published in the most recent years examined (1995-1998) did not include ethnicity in their analyses or design.