Minimum Selenium Requirements Increase When Repleting Second-Generation Selenium-Deficient Rats but Are Not Further Altered by Vitamin E Deficiency.

Second-generation selenium-deficient weanling rats fed graded levels of dietary Se were used (a) to study the impact of initial Se deficiency on dietary Se requirements; (b) to determine if further decreases in selenoperoxidase expression, especially glutathione peroxidase 4 (Gpx4), affect growth or gross disease; and (c) to examine the impact of vitamin E deficiency on biochemical and molecular biomarkers of Se status. Rats were fed a vitamin E-deficient and Se-deficient crystalline amino acid diet (3 ng Se/g diet) or that diet supplemented with 100 µg/g all-rac-α-tocopheryl acetate and/or 0, 0.02, 0.05, 0.075, 0.1, or 0.2 µg Se/g diet as Na2SeO3 for 28 days. Se-supplemented rats grew 6.91 g/day as compared to 2.17 and 3.87 g/day for vitamin E-deficient/Se-deficient and vitamin E-supplemented/Se-deficient groups, respectively. In Se-deficient rats, liver Se, plasma Gpx3, red blood cell Gpx1, liver Gpx1 and Gpx4 activities, and liver Gpx1 mRNA levels decreased to <1, <1, 21, 1.6, 49, and 11 %, respectively, of levels in rats fed 0.2 µg Se/g diet. For all biomarkers, ANOVA indicated significant effects of dietary Se, but no significant effects of vitamin E or vitamin E × Se interaction, showing that vitamin E deficiency, even in severely Se-deficient rat pups, does not result in compensatory changes in these biochemical and molecular biomarkers of selenoprotein expression. Se requirements determined in this study, however, were >50 % higher than in previous studies that started with Se-adequate rats, demonstrating that dietary Se requirements determined using initially Se-deficient animals can result in overestimation of Se requirements.

Blood glutathione peroxidase-1 mRNA levels can be used as molecular biomarkers to determine dietary selenium requirements in rats.

Transcript (mRNA) levels are increasingly being used in medicine as molecular biomarkers for disease and disease risk, including use of whole blood as a target tissue for analysis. Development of blood molecular biomarkers for nutritional status, too, has potential application that parallels opportunities in medicine, including providing solid data for individualized nutrition. We previously reported that blood glutathione peroxidase-1 (Gpx1) mRNA was expressed at levels comparable to major tissues in rats and humans. To determine the efficacy of using blood Gpx1 mRNA to assess selenium (Se) status and requirements, we fed graded levels of Se (0-0.3 microg Se/g as selenite) to weanling male rats. Se status was determined by liver Se concentration and selenoenzyme activity, and selenoprotein mRNA abundance in liver and blood was determined by ribonuclease protection analysis. Liver Se and plasma glutathione peroxidase-3 and liver Gpx1 activities indicated that minimal Se requirements were at 0.08 microg Se/g diet. When total RNA was isolated from whole blood, Gpx1 mRNA in Se-deficient rats decreased to 10% of levels in Se-adequate (0.2 microg Se/g diet) rats. With Se supplementation, blood Gpx1 mRNA levels increased sigmoidally to a plateau with a minimum Se requirement of 0.08 microg Se/g diet, whereas glutathione peroxidase-4 mRNA levels were unaffected. Similarly, Gpx1 mRNA in RNA isolated from fractionated red blood cells decreased in Se-deficient rats to 23% of Se-adequate levels, with a minimum Se requirement of 0.09 microg Se/g diet. Additional studies showed that the preponderance of whole blood Gpx1 mRNA arises from erythroid cells, most likely reticulocytes and young erythrocytes. In summary, whole blood selenoprotein mRNA levels can be used as molecular biomarkers for assessing Se requirements, illustrating that whole blood has potential as a target tissue in development of molecular biomarkers for use in nutrition as well as in medicine.

Dietary selenium requirements based on tissue selenium concentration and glutathione peroxidase activities in old female rats.

Dietary nutrient requirements for older animals have been studied far less than have requirements for young growing animals. To determine dietary selenium (Se) requirements in old rats, we fed female weanling rats a Se-deficient diet (0.007 microg Se/g) or supplemented rats with graded levels of dietary Se (0-0.3 microg Se/g) as Na(2)SeO(3) for 52 weeks. At no point did Se deficiency or level of Se supplementation have a significant effect (P>0.05) on growth. To determine Se requirements, Se response curves were determined for 7 Se-dependent parameters. We found that minimum dietary Se requirements in year-old female rats were at or below 0.05 microg Se/g diet based on liver Se, red blood cell glutathione peroxidase (Gpx1) activity, plasma Gpx3 activity, liver and kidney Gpx1 activity, and liver and kidney Gpx4 activity. In conclusion, this study found that dietary Se requirements in old female rats were decreased at least 50% relative to requirements found in young, rapidly growing female rats. Collectively, this indicates that the homeostatic mechanisms related to retention and maintenance of Se status are still fully functional in old female rats.

The influence of reported trauma and adverse events on eating disturbance in young adults.

OBJECTIVE: Early experiences of trauma or adverse events may be associated with eating disturbance later in life, but evidence is scarce. This study examined whether reported history of adverse life events predicted eating disturbance upon college entry and prospective changes over the first semester of college. METHOD: First semester college students (n = 249) reported trauma/adverse event histories and completed disordered eating questions (with two factors, restriction and binging/purging) at the beginning and end of their first semester. RESULTS: At college entry, trauma type, frequency, and overall trauma severity were related to restricted eating, and trauma type and severity was related to binging/purging. Prospective increases in reported restricted eating were predicted by trauma type. Prospective increases in binging/purging were associated with trauma type and total trauma severity. CONCLUSION: These data suggest that reports of past trauma and adverse events cross-sectionally predict reported disordered eating at college entry as well as prospective increases in disordered eating over the first semester of college. Research and clinical implications for these findings are discussed.

Alcohol-related legal infractions and student retention.

OBJECTIVE: The present study employed municipal alcohol-related arrest reports to determine if being arrested/cited reduced the probability of academic retention. METHOD: Alcohol-related legal infraction data implicating 1,310 college students was gathered during a 4-year period. First- through third-year students were identified in the database by cross-checking names in the campus directory. A random sample of nonarrested students functioned as the comparison group (n = 856). Students not appearing in the directory the following year were defined as nonretained students. RESULTS: Retention was not affected by the experience of one alcohol-related legal infraction. Retention odds were 31% lower for students experiencing multiple arrests, however, than for nonarrested or single-arrested students. Gender moderated the association between arrest and retention, with women who had been arrested more likely to return to school than those who had not been arrested. Retention odds were higher for arrested/cited students if they were in their second or third year of college, a fraternity/sorority member, or charged with an offense other than driving under the influence. CONCLUSIONS: Multi-arrested college students are at risk for attrition. Immersion in college life may reduce the odds of attrition among arrested college students.

Dietary selenium requirements based on glutathione peroxidase-1 activity and mRNA levels and other Se-dependent parameters are not increased by pregnancy and lactation in rats.

The hierarchy of selenium (Se) requirements for growing rats ranges from <0.01 to 0.1 microg Se/g diet, depending on the choice of Se status parameter. To further evaluate the efficacy of molecular biology markers to determine Se requirements in later periods of the life cycle, which are less amenable to traditional approaches, we studied pregnant and lactating rats. Female weanling rats were fed a Se-deficient diet (<0.01 microg Se/g) or supplemented with graded levels of dietary Se (0-0.3 microg Se/g) for >10 wk, bred, and killed on d 1, 12, and 18 of pregnancy and d 7 and 18 of lactation; Se response curves were determined for 10 parameters including liver glutathione peroxidase (GPX). Growth, and mRNA levels for selenoprotein P, 5'-deiodinase, and GPX4 were not decreased by Se deficiency. GPX4 activity required 0.05 microg Se/g diet for maximum activity, similar to growing rats. Dietary Se requirements for plasma GPX3 activity decreased 33% in pregnancy, but returned during lactation to the requirement of growing rats. The Se requirement for GPX1 activity decreased 25% in pregnancy but not in lactation. GPX1 mRNA required 0.05 microg Se/g diet for maximum levels in both pregnancy and lactation, similar to growing rats. Clearly, Se requirements do not increase during pregnancy and lactation relative to Se requirements in growing rats. Unexpectedly, Se-adequate levels of GPX1 mRNA and activity declined to <40 and 50%, respectively, of nonpregnant Se-adequate levels during pregnancy and lactation, illustrating the need to fully understand biomarkers at all stages of the life cycle.

Sexual trauma, spirituality, and psychopathology.

This study assessed the association between spirituality and psychopathology in a group of sexual abuse victims and controls with a focus on whether spirituality moderated the association between sexual trauma and psychopathology. Seventy-one sexual trauma victims were compared to 25 control subjects on spiritual well-being, the Eating Disorder Examination, the PTSD Symptom Scale, and the SCID-I/P. The data showed that the two groups did not differ in terms of spiritual well-being. Sexual trauma status was associated with most of the psychopathology outcomes, but its impact on psychopathology was largely unmoderated by spirituality. Among sexual trauma victims, the level of spiritual well-being did not alter the probability of current psychopathology. However, increased spiritual well-being was generally associated with lower psychopathology for the entire sample.

Psychopathology and sexual trauma in childhood and adulthood.

This study evaluates the occurrence of psychopathology among 97 women who (1) experienced sexual abuse in childhood only, (2) were raped in adulthood only, (3) experienced both childhood sexual abuse and rape in adulthood, or (4) experienced no sexual trauma. Women were recruited from advertisements and assessed using the Structured Clinical Interview for DSM-IV (SCID-I/P) and the Modified PTSD Symptom Scale Self-Report. Women who reported sexual trauma were significantly more likely to exhibit psychopathology than controls. Being sexually victimized in childhood and raped in adulthood was associated with a particular risk for substance dependence.

Adolescent and adult alcohol attitudes in a high alcohol consumption community.

The study examines alcohol-related attitudes among adolescents and adults in a high consumption community, exploring whether adolescents and adults hold similar or different views regarding adolescent drinking. Data were gathered from adults in a Midwestern city via random telephone survey of 487 adults (30% with children under the age of 21). Students in grades 6-12 (n = 558) also completed a youth version of the survey in classrooms. Results indicated that becoming a parent was associated with more restrictive attitudes about adolescent alcohol use, regardless of the age of their children. Adolescents aged 14 to 17 had the least restrictive attitudes. Adults aged 18 to 24 (who were not parents) reported values similar to older adolescents. Younger adolescents, while similar to older adolescents in perception of community alcohol problems, were more like parents and older adults in attitudes about adolescent drinking. Both adolescents and adults greatly overestimated actual amounts of community adolescent binge drinking.

Dietary selenium regulation of glutathione peroxidase mRNA and other selenium-dependent parameters in male rats.

Weanling male rats were fed a basal torula yeast diet (0.007 µg Se/g diet) supplemented with graded levels of Se (0 to 0.2 µg Se/g diet as Na2SeO3) (three rats/group) to evaluate classical glutathione peroxidase (GPX1, GSH:H2O2, oxidoreductase, EC 1.11.1.9) mRNA level as an indicator of intracellular Se status. Growth was followed throughout the dietary treatment and a number of Se-dependent parameters including liver GPX1 mRNA levels were determined after 33 days. Growth was not impaired at any level of dietary Se supplementation. In rats fed the Se-deficient basal diet, liver Se concentration was 5 ± 1%, liver GPXI mRNA levels were 10 ± 2%. plasma GPX activity was 2 ± 1%, erythrocyte GPX activity was 37 ± 1%, and liver GPX activity was 0 ± 2% of the levels in rats fed 0.1 µg Se/g diet; these parameters increased sigmoidally with increasing dietary Se, showing a breakpoint near 0.1 µg Se/g diet. Graphical analysis indicated that the increase in liver GPX1 mRNA level with increasing dietary Se, preceded the increase in liver GPX activity. Se supplementation had no effect on polyadenylated mRNA levels or on ß-actin mRNA levels, demonstrating that Se regulation of GPX1 mRNA is specific. Se-deficient liver selenoprotein P mRNA levels were 69 ± 2% of the levels in rats fed 0.1 µg Se/g diet. We hypothesize that GPX1 mRNA is a primary target of the Se regulatory mechanism, making GPX1 mRNA level a potentially useful indicator of the status of an important intracellular regulatory pool of Se.