Residual effects of food deprivation on food consumption and runway performance in the satiated rat.

2 experiments studied the residual effects of prior food deprivation in 35 female and 28 male Holtzman rats as measured by probability to eat and acquisition of a running response under satiated conditions. Although the effects were positively related to the severity of prior deprivation (Exp II), a drive-conditioning interpretation was questioned because of 3 findings: (a) effects were not dependent on exposure to the test situation when Ss were deprived (Exp I and II); (b) prolonged testing during satiation increased rather than decreased the effects (Exp I and II); and (c) the instrumental response decreased only when reward was withheld (Exp I). (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sex differences in dehydroepiandrosterone-induced hepatocarcinogenesis in the rat

The direct quantification of antibiotics in agar allows one to study the quality of the agar matrix, the kinetics of diffusion and the bacteria-antibiotic interaction. Mueller-Hinton agar (MHA) plates from three manufacturers were tested using HPLC and the disc diffusion test of ceftazidime (CAZ). Notable differences in the chromatographic profiles of MHA plate extracts from OXOID, DID and Becton Dickinson (BD) were shown, with a higher CAZ concentration after 24 h a 6 mm in BD P. aeruginosa inoculated plates (5.1 +/- 1.7 micrograms/ml, n = 6) vs. OXOID and DID (1.6 +/- 0.3 micrograms/ml, n = 12). BD plates gave also a different inhibition zone diameter (26 +/- 0.5 mm, n = 3) with respect to DID and OXOID (29 +/- 0.5 mm, n = 3).     

Sex differences in the relationship between activity and weight loss in the rat.

Access to a running wheel combined with restricted feeding produced body weight loss at an equivalent rate in male and female litter-mate rats (Experiment 1). Thus, despite weighing less and running more, females were not more vulnerable to this procedure. When factors influencing weight loss were varied, no sex difference was found in adaptation to a new feeding schedule or in the effect of single versus group housing (Experiment 2). The apparent critical difference was that body weight loss increased running in males but not in females (Experiment 3). In all rats, rapid recovery of body weight occurred when food access was no longer restricted (Experiment 1), suggesting that "activity-based anorexia" is a misnomer for weight loss by rats in a running wheel. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Relations of heart rate level to motor activity and food deprivation in the rat.

Measured heart rate, an activity index, and duration of grooming and rearing episodes in 10 male hooded rats which leverpressed under either continuous or VI schedules of reinforcement while undergoing increasing levels of food deprivation. Results show that heart rate level did not change with increasing deprivation and was not influenced by activity levels or behavior patterns (e.g., rearing or grooming). Extinction produced a decrease in heart rate level, though behavior became more invigorated. Observations of phasic heart rate and activity curves associated with instrumental lever responses are also presented. Data are discussed in relation to studies showing heart rate-deprivation functions and heart rate-movement associations. (French summary) (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sex differences in discriminative stimulus and diuretic effects of the kappa opioid agonist U69,593 in the rat

BACKGROUND AND PURPOSE: The purpose of this study was to determine the effect of change in video display terminal (VDT) height from desktop height (96.5 cm [38 in]) to an elevated position (109.2 cm [43 in]) on postural angles of the head and neck and the effect on cervical spine flexion moments. SUBJECTS: Twenty-seven persons (3 male, 24 female) who spent at least 3 hours per day using a computer while seated were the subjects. The subjects had a mean age of 36.7 years (SD=6.0, range=25-47). METHODS: Subjects were photographed over two 10-minute periods while seated using a computer with the VDT at two different heights. Later, a goniometer was used over images to record angles. RESULTS: There was no difference in cervical flexion moment between the two screen positions. Several postural angles of the head and neck showed changes, but the clinical relevance of these changes is questionable. CONCLUSION AND DISCUSSION: Changing the VDT height from 96.5 to 109.2 cm (floor to midscreen) has no effect on flexion moment on the cervical spine during short periods of VDT operation. If flexion moment is considered a biomechanical indicator of postural stress, it does not appear that the elevated screen position reduces postural stress on the cervical spine during short periods of VDT operation.     

Sex differences in hepatic sulfation of taurolithocholate in the rat

Metabolism of the bile salts by formation of sulfate esters is catalyzed by bile salt sulfotransferase, an enzyme isolated from rat liver and kidney. The activity of bile salt sulfotransferase was measured in liver and kidney of male and female rats and in oophorectomized rats with or without estrogen replacement. In vitro sulfotransferase activity was correlated with in vivo sulfation by measuring the percentage of an infused dose (0.03 micron per 100 g per min) of taurolithocholate, which was excreted in bile as the sulfate. The activity of sulfotransferase in liver was higher in females (26.3 +/- 3.0 pmoles per mg of protein per min) than in males (9.6 +/- 3.9) and was lower (12.1 +/- 3.8) after oophorectomy. The decrease in activity was prevented by replacement of estrogen. Renal sulfotransferase activity did not differ between the sexes and was unaffected by oophorectomy. Hepatic sulfotransferase activity measured in vitro correlated with in vivo sulfation of taurolithocholate. This study shows definite sex differences in hepatic bile salt sulfotransferase activity, which in females is affected by the presence of estrogen. The correlation between in vitro sulfotransferase activity and in vivo bile salt sulfation suggests that bile salt sulfotransferase is responsible for bile salt sulfation in vivo.     

Sex differences in effects of social and value similarity in same-sex friendship.

Explored sex differences in effects of social and value similarity in a longitudinal study of 146 same-sex college roommate pairs (62 male and 84 female). The clearest findings concerned actual value similarity among women; those who chose each other as roommates were more similar than those who had been assigned to be roommates. Actual value similarity (measured in the fall quarter) was correlated with liking in the fall and liking in the spring among female chosen pairs; it also predicted which female assigned pairs would remain roommates. None of the analyses of actual value similarity was significant for men, although tests of sex differences in effects yielded mixed results. Few effects were obtained for similarity on social characteristics, except for similarity on year in college. Results are discussed in terms of prior roommate studies, and issues are raised concerning the use of roommates in research on friendship development. (28 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sex differences in influenceability.

Examines the hypothesis that women are more influenceable than men in a variety of situations. For persuasion research and for conformity studies not involving group pressure, there is scant empirical support for a sex difference, and for group pressure conformity research, there is support among a substantial minority of studies. Also explored is the possibility that various sex differences in social influence studies are a product of contextual features of experimental settings. This is suggested by the fact that findings reporting greater influenceability among females were more prevalent in studies published prior to 1970 than in those published in the 1970s. Finally, sex differences in various psychological processes that may mediate persuasion and conformity are evaluated as possible explanations for those influenceability sex differences that appear to be genuine. It is suggested that a propensity to yield inherent in the female sex role appears to account for some aspects of influenceability findings, but a 2nd explanation, a tendency for women more than men to be oriented to interpersonal goals in group settings, is also plausible. (7? p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Analytical issues in the evaluation of food deprivation and sucrose concentration effects on the microstructure of licking behavior in the rat

A microstructural analysis of licking behavior in nondeprived and 23-hr food-deprived rats (n = 15) presented with various sucrose solutions (0.03-1.0 M) in daily single-bottle, 1-hr sessions was conducted. Food deprivation and concentration interacted to increase total licks. The effects of food deprivation and concentration on burst size (BS), burst number (BN), and other parameters varied as a function of the pause criterion (PC; 0.3-100 s) used to define licking bursts. A rationale for selecting a 1-s PC for further analysis is presented. Despite the lack of correlations between temporally contiguous burst and pause combinations, mean BS decreased and pause duration increased as meals progressed. At the 1-s PC, BS increased linearly with concentration, implying that this microstructural parameter is influenced in part by taste. Food deprivation did not affect BS but rather increased BN and proportionally extended the meal duration.     

Sex and menstrual cycle differences in the subjective effects from smoked cocaine in humans.

To investigate sex and menstrual cycle effects in response to cocaine administration, data from existing studies were analyzed. First, responses to a single delivery of 0.4 mg/kg smoked cocaine were investigated. Women reported lower ratings for measures of paranoid/suspicious and heart racing/pounding than did men. In addition, women in the luteal phase reported diminished ratings for a measure of feel high than did both women in the follicular phase of the menstrual cycle and men. Second, responses to up to 6 deliveries of 0.4 mg/kg smoked cocaine were investigated. Women, compared with men, had lower ratings on feel high, heart racing/pounding, and feel stimulated. Results suggest that there are significant sex and menstrual phase differences in the subjective effects of cocaine. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sex differences in the allocation of pay.

Examined the possibility that relative to males, females perceive less of a connection between their work and monetary rewards. In Study 1, 66 females and 60 males (respondents to an advertisement in a student newspaper) determined either their own pay or the pay of another person. Results support the hypothesis in that females paid themselves less than did males and less than other people (males or females) paid females. Results also suggest that Ss were more generous when they paid females. In Study 2, sex differences in self-pay were examined in 80 1st-, 4th-, 7th-, and 10th-grade Ss. Results replicate those of Study 1, in that at every grade level, females paid themselves less than did males. In addition, the extent to which females allocated pay the way their male counterparts did was highly related to the masculinity of their career goals. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sex differences in health and illness.

The literature on sex differences in illness and disease was examined. Although some biologic sex differences are thought to exist, the overlap between the sexes precluded separation of the sexes for treatment or control of problem conditions. Statistics Canada data on mental illness among males and females in Canada were also examined, and deficiencies in available information were discussed. Most notably lacking were statistics on the use of outpatient mental health services. A number of recommendations were made regarding the collection of Canadian mental health statistics. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Behavioral consequences of agonistic experience in rats: Sex differences and the effects of testosterone.

Studied the effects of winning or losing on subsequent aggressive behavior in male and female rats. By using 3 strains with different levels of aggression (40 WEzob, 40 S3, and 40 Wistar), a procedure was developed to create winners and losers. Subsequently, winners were tested against losers. Behavioral analysis of all tests enabled a thorough study of these processes and of their consequences. Results (1) indicate that significant and relatively permanent behavioral changes were induced in intact and castrated, testosterone-treated males but not in females and (2) suggest that behavioral inhibition is a specific characteristic of the male's agonistic behavioral repertoire. (30 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sex differences and placebo effects: Motivation as an intervening variable.

Investigated the effects of sex, motivation (positive or neutral) and placebo on the dynamometer performance of undergraduates. As predicted, given the level of motivation appropriate for S's sex, males and females did not differ in the effects of the placebo. However, males in the neutral motivation condition were significantly more affected by the placebo than females. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sex differences in monitoring performance.

220 male and 220 female undergraduates monitored a visual display for 1 hr. Although the results indicate females were poorer monitors, detecting 10% fewer signals and committing more false alarms, these sex differences accounted for only 4% of the variance of detection performance and less than 1% of the variance of the false alarm measure. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sex differences in problem solving.

Used a 20-item set of problems (similar to those used by E. Sweeney [1953]) in 9 experiments with 558 male and 578 female undergraduates to determine which sex was superior in problem solving, the role of previous experience, whether sex differences extended throughout the domain of problem-solving tasks, whether they extended to other word problems, the role of spatial ability and verbal ability, the role of mathematics aptitude, and the relative importance of aptitude and social learning variables. Results show that the male advantage, averaging 35% across experiments, persisted at the same level as in experiments conducted in the 1950's. Sex differences extended to other word problems. The male advantage was related to similar advantages in spatial and mathematical ability. Aptitude variables dominated attitude and mathematics experience variables in accounting for the sex difference. (48 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sex differences and adolescent depression.

This study investigates the role of certain psychosocial variables—sex, age, body image/self-esteem, self-consciousness, stressful life events, and the degree to which an individual identifies with the cultural stereotype of masculinity—as correlates and antecedents to depression in adolescents and explores possible intraindividual mediators of the stress–depression relationship in adolescents. A battery of self-report measures was administered to public high school students in Grades 9–12 in their classrooms at two different times 1 month apart. Female adolescents reported more depressive symptoms, self-consciousness, stressful recent events, feminine attributes, and negative body image and self-esteem; no age effects were obtained. Results suggest a model of adolescent depression in which body image/self-esteem and stressful recent events are significant contributors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sex differences in altruistic behavior.

Assessed helping and donation behavior in 35 female and 35 male White middle-class 5th graders. Results reveal (a) no significant differences between male and female donation behavior, (b) significantly more helping behavior from females, and (c) no significant correlations between donation and helping behavior. Since helping behavior was only observed in situations with same-sexed younger children, future investigations should include both opposite- and same-sexed pairs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sex differences in job satisfaction.

Measures of 5 separate aspects of job satisfaction gathered from 295 male workers and 163 female workers drawn from 4 different plants were analyzed with respect to the mean job satisfaction for the male and female workers. T2 analyses indicated that in 3 plants the female workers were significantly less satisfied than their male counterparts (p     

Sex differences in effects of predictable and unpredictable footshock on fentanyl self-administration in rats.

An operant conditioning paradigm was used to examine effects of predictable and unpredictable footshock on oral fentanyl (50 μg/ml) self-administration (SA) in 12 female and 12 male Wistar rats (Rattus norvegicus). Rats were tested for drug SA under a progressive ratio schedule with and without repeated predictable or unpredictable footshock over 8 weeks. Female rats consumed greater amounts of fentanyl than did male rats. Male rats exhibited greater withdrawal behaviors following naloxone challenge. Predictable footshock with repeated exposure (i.e., chronic stress) was accompanied by greater fentanyl SA than was unpredictable footshock, particularly for female rats. Corticosterone levels were positively correlated with fentanyl SA. Predictability of the stressor also had a greater effect on maintenance of fentanyl SA than it did on relapse to fentanyl SA. Results suggest that sex plays an important role in drug-taking behavior by rats. (PsycINFO Database Record (c) 2010 APA, all rights reserved)