Induction of DNA-strand breaks in human peripheral blood lymphocytes and A549 lung cells by sodium dichromate: association with 8-oxo-2-deoxyguanosine formation and inter-individual variability.

Hexavalent chromium [Cr(VI)] is a genotoxic carcinogen for which inhalation is a major potential route of exposure in occupational settings. In the present study, the ability of sodium dichromate to cause DNA strand breaks in three populations of cells, human whole blood cells, isolated human peripheral blood lymphocytes and cultured A549 lung epithelial cells, was investigated. Treatment with non-cytotoxic concentrations of sodium dichromate (for 1 h) resulted in a concentration-dependent increase in the number of DNA strand breaks as measured by the Comet assay. The lowest concentrations of sodium dichromate that resulted in a statistically significant (P < 0.01) increase in the number of DNA strand breaks were 500, 50 and 10 microM, respectively, in these cells. The use of formamidopyrimidine glycosylase increased the sensitivity of detection of strand breaks in A549 cells 10-fold, suggesting a role for DNA base oxidation in the mechanism of dichromate-induced DNA strand breaks. In support of this hypothesis, immunocytochemistry indicated an elevation of 8-oxodeoxyguanosine in A549 cells treated with 10 and 500 microM sodium dichromate for 1 h. We also demonstrated 2.11- and 2.5-fold ranges in the level of control and dichromate (500 microM)-induced DNA strand breaks, respectively, in cells of whole blood within a group of healthy volunteers (n = 26). A statistically significant (P < 0.001) positive Pearson's correlation (r = 0.606) was found between control and treated levels of DNA strand breaks, suggesting that factors responsible for relatively low levels of DNA strand breaks in untreated PBL may also offer protection against the formation of dichromate-induced DNA strand breaks.

Establishing an occupational exposure limit for hexavalent chromium in the European Union.

A Criteria Document for hexavalent chromium [Cr(VI)], currently under preparation at the Institute of Occupational Health, University of Birmingham, is intended for use in setting an occupational exposure limit (OEL) for Cr(VI) in the European Union (EU). The requirement for establishing OELs, specifically known as indicative limit values, in the EU is set out in Council Directive 80/1107/EEC, amended by Council Directive 88/642/EEC. To facilitate this procedure the Commission has set up a Scientific Committee for Occupational Exposure Limits to Chemical Agents. The Committee, which is composed of independent scientific experts from member states, is responsible for reviewing available scientific data. A Criteria Document forms the basis of the scientific data considered during this process and contains an up-to-date, critical evaluation of available information which is relevant to setting an exposure limit. After consideration of the scientific data for a particular substance, the Committee advises the Commission on setting a health-based OEL. Consideration of other questions such as technical matters and socioeconomic issues occurs during later stages of the procedure, before an OEL is finally adopted. The procedure allows for consultation with interested parties. The Criteria Document for Cr(VI) contains sections on substance identification, chemical and physical properties, production and use data, recent data on occupational exposure, current methods for measurement and analysis, and toxicology. The toxicology section contains a critical evaluation of both human and animal data and forms a major part of the document. This section enables identification of critical health effects associated with exposure to Cr(VI) and consideration of dose-response relationships and provides the basis for any risk assessment and recommendation for an OEL.

Effect of quercetin on the genotoxic potential of cisplatin.

The natural product flavonoid quercetin has been shown to sensitise cells to the cytotoxic potential of cisplatin. Both cisplatin and quercetin are genotoxicants. As quercetin is currently in clinical trial as a cytotoxicant-sensitising agent, we wanted to elucidate whether it affects the genotoxicity associated with cisplatin. The genotoxic potential of both agents alone and in combination was studied in Salmonella typhimurium strains TA 98, TA 100 and TA 102 and by assessment of unscheduled DNA synthesis (UDS) in rat hepatocytes. Furthermore, effects of quercetin on levels of cisplatin-DNA adducts were studied in hepatocytes by ELISA. Cisplatin was mutagenic in all 3 bacterial strains and quercetin in strain TA 98. The number of revertant Salmonella colonies observed with the combination did not differ significantly from that caused by the drugs on their own. In the UDS assay, cisplatin was genotoxic but quercetin was not. In combination, quercetin decreased the nuclear grain count caused by cisplatin, but quercetin did not alter the level of cisplatin-DNA adduct formation in hepatocytes. Our results suggest that the mutagenic potential of the combination cisplatin-quercetin, as judged by the bacterial short-term test, does not exceed that associated with the individual components. However, in hepatocytes, quercetin appears to inhibit repair of cisplatin-induced DNA damage. Therefore, in patients who are to be treated with a combination of cisplatin and quercetin, the risk of genotoxicity in normal tissues will have to be taken into consideration.

Semistructured child sexual abuse interviews: interview and child characteristics related to credibility of disclosure.

This study provided the first empirical description of child and interviewer behaviors occurring within semistructured assessment interviews with children suspected of being victims of sexual abuse. Specifically, relationships between child and interviewer characteristics and interview credibility were examined. Using the Child Abuse Interview Interaction Coding System (CAIICS, Wood, 1990), 55 videotaped interviews of high-risk sex abuse cases seen at a multidisciplinary assessment center were behaviorally coded. Support was found for the interrater reliability and criterion related validity of the CAIICS was found. Results also revealed that children were initially rated as relaxed and displayed few emotional behaviors. Thus, the assumption that a credible disclosure of abuse must necessarily include the display of emotion by the child was not supported. Second, several behavioral differences between preschool and school-aged children were identified: however, no meaningful gender differences were found. Third, supporting evidence was found for both age and gender effects in judgments of interview credibility, with girls and school-aged children judged as more credible. Fourth, while the interviewer did engage in so called leading behaviors, these behaviors were not found to be related to rating of interview credibility. However, interviewer behaviors may have affected interview credibility through an intervening variable. Finally, implications, for further use of the CAIICS for examining interviewer-child interactions, evaluating standards of practice, and assisting with interviewer training are discussed.

The influence of acculturation and racial identity attitudes on Mexican-Americans' MMPI-2 performance.

Examination of the relationships among acculturation, racial identity, and the newly revised MMPI is warranted. This study investigated the degree to which racial identity influences Mexican-Americans' performance on the L, K, and MF scales of the MMPI-2. Also investigated were individual differences in performance on the L, K, and MF scales as a function of acculturation. Fifty-one Mexican-American undergraduates from Washington State University participated by completing an acculturation scale, a racial identity attitude scale, and the MMPI-2. Results indicated that performance on the L and K scales is influenced by racial identity attitudes and levels of acculturation, however, no evidence was found to suggest a relationship between cultural variables and performance on the MF scale.

Hypnotically created pseudomemories: further investigation into the "memory distortion or response bias" question.

In order to study whether pseudomemories represent actual memory distortions or are a result of response bias, 60 highly hypnotizable subjects and subjects from the general population were divided into 4 experimental groups and were tested for pseudomemory manifestation after receiving a false suggestion. Of the 4 groups of subjects, 3 were offered a monetary reward as a motivation to distinguish false suggestion from actual occurrence. Pseudomemory manifestation was found to be significantly higher among subjects not offered a reward than among subjects who were offered such an reward. The implications of these findings are discussed.

Modifying hypnotic suggestibility with the Carleton Skills Training program.

The Carleton Skills Training (CST) program was used to investigate (a) whether increases in hypnotic responsiveness obtained at Carleton University could be replicated at a different laboratory, (b) the influence of demand characteristics on suggestibility gains, and (c) whether initial gains are maintained over time. After two screening sessions, a replication and experimental group received the CST program, while a control group was allowed to practice hypnotic responding. All groups were then tested twice. Whereas the replication group was told that training and testing were part of the same experiment, the experimental group was told that training and testing were unrelated. Trained subjects returned after 4 months for a final session. Results indicated that (a) the CST program does increase hypnotic responsiveness, (b) suggestibility gains found in this study were relatively modest, (c) demand characteristics may influence suggestibility gains, and (d) suggestibility gains were not maintained at follow-up.

Correlates of the MMPI LB scale in a college population.

Administered the Low Back Pain Scale (LB) and the K Scale of the MMPI, the College Schedule of Recent Experience (CSRE), a psychosomatic disorder checklist, and the item, "I frequently have problems with my mother," to 53 male and 70 female college freshmen. Ss with a psychosomatic disorder scored higher on LB and on the CSRE. Females who reported problems with their mothers were more likely to have a psychosomatic disorder. The results suggest different etiology for psychosomatic disorders between males and females.

A social-learning approach to student marijuana use.

Three hundred seventy-two college students were administered a battery of questionnaires designed to assess the predictive power of four social variables (social support, perceived sanctions, availability, family models), and six psychological ones (locus of control, mortality-conscience guilt, personal meanings, functions for continuing use, belief in consequences, societal and non-societal means of valued goal attainment) with respect to marijuana use. Results support a social learning theory interpretation of marijuana use. Users have had pleasant experiences, believe that sanctions are minimal, and that marijuana is not harmful. Six predictor variables correlated +.76 with use.

Sexual stereotyping of black males in interracial sex.

Beliefs about black males' sexuality are pervasive in this society, but little studied. This investigation examined white subjects' perceptions of black and white characters in sexually explicit stories, some of which depicted interracial pairings. The perceptions were then examined in relationship to authoritarianism and sexual repression. Overall results suggest that black males are stereotyped as more potent than white males. The theoretical implications of this finding are discussed.

A comparison of chronic versus casual marijuana users on personal values and behavioral orientations.

Fifty-one chronic (daily) long-term marijuana smokers and 32 casual (1 to 3 times per week) users were interviewed and given a Rokeach Value Survey, a Personal Orientation Inventory (POI), and a Zuckerman Multiple Affect Adjective Check List. Value survey results showed that the two groups had the same general value structure. The POI showed no differences between the groups, and the adjective self-ratings were similar. The groups were significantly different on a number of social variables; number of user friends, longest period without drugs, perceived risk, etc., which indicated "drug subculture involvement." Results are discussed from a sociological point of view.