Tolerance development to cadmium-induced alteration of drug action

Cadmium administration potentiates the duration of hexobarbital-induced hypnosis and inhibits the rate of hepatic microsomal metabolism of this drug in the male rat. The threshold dose of cadmium required to produce these alterations in drug action is 0.84 mg Ck/kg. If subthreshold doses of cadmium (0.21 or 0.42 mg Cd/kg) are administered prior to the 0.84 mg Cd/kg dose, the cadmium-induced alterations in drug action are no longer observed.     

Sex-related differences in thermoregulatory responses while wearing protective clothing

In previous studies on the formation of Lymantria dispar nuclear polyhedrosis virus (LdMNPV) few polyhedra (FP) mutants, several polyhedron formation mutants (PFM) were identified that appeared to be unique. These viral mutants are being characterized to investigate the processes of polyhedron formation and virion occlusion. LdMNPV isolate PFM-1 is one of these mutants, and is described in this report. Genetic techniques were used to determine if isolate PFM-1 contained a mutation in the polyhedrin or 25K FP gene. Wild-type viruses were recovered after coinfection of Ld652Y cells with isolate PFM-1 and a FP mutant, and with isolates PFM-1 and PFM-C (isolate PFM-C contains a mutation in the polyhedrin gene). These viruses were analyzed by genomic restriction endonuclease digestion and found to be chimeras of the original PFMs used in the coinfections. Marker rescue studies mapped the mutation in isolate PFM-1 to a genomic region that does not include the polyhedrin or 25K FP genes. Isolate PFM-1 produced approximately 14-fold fewer polyhedra than LdMNPV isolate A21-MPV, an isolate that produces wild-type levels of polyhedra, and approximately 2-fold more polyhedra compared to the FP isolate 122-2. Polyhedra generated by isolate PFM-1 were normal in size and shape but contained very few viral nucleocapsids. The same amount of budded virus (BV) was released from cells infected with isolates PFM-1 and A21-MPV. In contrast, isolate 122-2 yielded significantly more BV than isolates PFM-1 and A21-MPV.     

Sex-related differences in spatial ability: Are they trivial?

Refutes the P. J. Caplan et al (see record 1986-10956-001) claim that no appreciable sex differences in spatial ability have been proven, suggesting that the Caplan et al study failed to (1) distinguish among studies that do and do not adequately reflect the spatial ability construct, (2) recognize well-established developmental differences in this ability, and (3) provide convincing documentation of the purported triviality of admitted differences. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sex-related differences in cortical function after medial frontal lesions in rats.

The effects of sex on the performance of 4 spatial mazes (Morris water task, landmark task, radial arm maze, and egocentric radial arm maze) were studied in male and female rats given medial frontal lesions. Operated rats from both sexes were impaired at all of the tasks, but the frontal males were much less impaired than frontal females on the Morris task and the radial arm maze, both of which require animals to use multiple visual-spatial cues for their successful solution. Males also performed better on the egocentric maze. In contrast, frontal females performed better than frontal males at the landmark task, which is best solved by using a single spatial cue. The only sex difference in unoperated rats was a small advantage for females on the egocentric task. The sex differences may reflect an underlying difference in cortical organization or a differential response to cortical lesion in males and females. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sex-related differences in spatial divided attention and motor impulsivity in rats.

The acquisition and performance of a self-paced test of spatial divided attention linked with frontal cortex function were assessed in postpubertal (> 60 days) normal or gonadectomized male and female rats. Males were more accurate at detecting relatively brief visual stimuli than females, but this difference was eliminated by increasing the target stimulus duration, indicating an attentional basis for this effect. Premature errors were, however, greater in males than in females, suggesting greater impulsivity in males. Subsequent experiments in gonadectomized rats suggest that circulating hormones influence attention and impulsivity, but not necessarily sex differences. These results demonstrate a double dissociation between components of impulse control and divided attention in male and female rats and may have implications for sex differences in disorders of attention and cognition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Professionals in scientific disciplines: Sex-related differences in working life commitments.

Examined sex differences in job involvement and organizational commitment along with issues pertaining to role conflicts, treatment on the job, and involvement in professional activities. Data were collected via a mail survey from 440 women and 447 men who were randomly selected from various professional societies. The mean age of women was 39.8 yrs; the mean age for males was 43.8 yrs. No significant differences were observed between men and women on the job involvement and professional activities scales. Men and women differed, however, on their level of organizational commitment, their perceptions of on-the-job treatment, and the extent of their role conflicts. These differences are discussed, and the stronger correlates of job and organizational commitment are identified. (13 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The magnified molehill and the misplaced focus: Sex-related differences in spatial ability revisited.

Refutes criticisms by J. Eliot, M. Hiscock, S. A. Burnett, D. F. Halpern, and B. Sanders et al (see PA, Vol 74:305, 310, 301, 309, and 324, respectively) of the present authors' (see record 1986-10956-001) findings that (a) no-difference results in studies of sex-related spatial ability are underreported and what differences are found are often exaggerated and (b) spatial abilities is an inadequate construct, rendering premature and even inappropriate the question of whether sex differences in this area exist. (16 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Gender differences in adverse drug reactions

The objective of this study is to identify gender-related differences in the types of symptoms and drugs reported to cause an adverse drug reaction. Patient data from the Sunnybrook Health Science Centre ADR Clinic for the period from April 1986 to May 1996 were reviewed. Of the 2,367 patients assessed, 74.1% were female. The mean age of the patients was 43 +/- 17 years. Drug classes most frequently reported to elicit an adverse event were general antiinfectives (60.4%), nervous system agents (21.5%), and musculoskeletal agents (3.7%). Skin-related reactions accounted for 49.0% of all reported adverse drug reactions. More than one agent was reported to be responsible for the adverse drug reaction(s) in 50% of the female patients, versus 33.1% of all male patients. Of the female patients, 47.6% were referred for skin or oral challenge testing, versus 41.6% of the male patients. Of the female patients, 6.2% tested positive to the agent compared with 6.1% of all male patients. These results support previous findings that female gender is a risk factor for the development of adverse drug reactions. Further work is required to elucidate the mechanisms explaining the differences observed between male and female patients.     

Performance on Piagetian horizontality and verticality tasks: Sex-related differences in knowledge of relevant physical phenomena.

College women consistently perform worse than college men on tasks devised by Piaget to assess children's horizontality and verticality concepts. To determine if these sex-related differences are due to inadequate knowledge of the behavior of water and plumb lines (performances) rather than to immature spatial concepts (competence), 80 male and 80 female college students in Study 1 received the tasks (a) with or without pictorial examples and (b) with or without a verbal rule concerning the relevant physical phenomena. As predicted, main effects for sex and rule were significant, although the pictorial example had no effect. Contrary to expectations, the rule did not lead females to perform as well as males. In Study 2, 80 male and 80 female college students received the tasks with or without the rule, but here the rule was presented more emphatically. Following the tasks proper, all Ss were asked to explain what rule (if any) they had used in answering. In the no-rule condition, males' and females' score distributions differed significantly, as did the types of explanations offered. In the rule condition, neither score distribution nor explanations differed significantly by sex. Results are consistent with a performance interpretation of females' difficulty on standard Piagetian tasks, and, taken with Study 1, demonstrate the importance of central rather than incidental presentation of the relevant information. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sex-related differences in event-related potentials, face recognition, and facial affect processing in prepubertal children.

Thirty-five prepubertal children, 17 boys and 18 girls, between the ages of 8 and 11 years, were studied to examine electrophysiological and cognitive sex differences during a face-recognition-memory (FRM) task and a facial-affect-identification task (FAIT). All participants were prepubertal, as determined by J. M. Tanner's (1962) staging and endocrine evaluation. Sex-dependent event-related potential (ERP) amplitude asymmetries were found during FRM. Boys displayed greater right versus left ERP amplitude to auditory tone probes during the task, whereas girls displayed the opposite pattern. In addition, positive correlations were obtained between ERP amplitude during FRM and FAIT accuracy scores for boys, but not for girls. Results suggest that girls and boys may use different neuronal systems in the processing of faces and facial affect. Findings are consistent with developmental theories regarding sex differences in visuospatial processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Phenylclindine-induced alteration in rat muscarinic cholinergic receptor regulation

A muscarinic cholinergic receptor binding profile was performed on 3 separate regions of the rat brain following administration of the drug phencyclidine (10 mg/kg, twice a day) for 10 days. Binding assays were performed on homogenates of the hippocampus, striatum and cortex using the ligand [3H]QNB. Scatchard analysis of the binding data revealed a statistically significant decrease in the number of [3H]QNB binding sites in all phencyclidine treated animals. Binding was 22% lower in the cortex and 16% lower in the hippocampus and striatum. Phencyclidine treatment did not significantly alter the affinity of the receptor for the ligands [3H]QNB, acetylcholine or phencyclidine. This decrease in CNS muscarinic receptors could be contributing to the underlying biochemical mechanism of tolerance to the drug.     

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).     

Regional differences in the morphology of the rat subfornical organ

Properties of whole milk and milk fractions from cows fed a diet that gave a greatly increased proportion of unsaturated fatty acid residues (especially of linoleic acid) in the milk lipids were studied, and this milk (high-linoleic milk) was compared with milk from cows on a control diet (control milk). The milk fractions were isolated by high-speed centrifugation of whole milk or cream and were examined by chemical analysis and electron microscopy. During centrifugation the globules of milk fat were disrupted and the membranes (fat-globule 'ghosts') floated as a layer beneath the free lipid. Membrane proteins from the 2 sorts of milk gave the same electrophoretic pattern and the amino acid compositions were the same. Lipid analysis of the membrane fraction from high-linoleic milk showed the expected increase in the proportion of unsaturated fatty acid residues in the neutral lipids, but there was an unexpected decrease in the proportion of unsaturated residues in the membrane phospholipids. No differences were found between high-linoleic and control milk in the ultrastructure of the milk-fat globules or the isolated membranes.     

Race and sex differences in the prediction of drug use.

Efforts to prevent adolescent substance abuse often direct prevention efforts at known correlates of substance use. The applicability to minority populations of risk factors uncovered for the general population has been questioned, and the development of different programs targeting the risk factors most salient for different groups has been recommended. Such differentiated programming requires a more precise understanding of ethnic differences in the predictors of substance use than is now available. This article assesses these differences using data from 981 Black and White male and female adolescents and latent variable structural equations techniques. No group differences were observed in the prediction of past year variety of drug use for 9 of the 12 risk factors examined. The predictive validity was higher for Whites than for Blacks for 3 risk factors. The prediction of frequency of use was weaker for Black women than for other groups. The low predictive validity observed for Black women is most likely due to the extremely low level of use among this group. The study concludes that the measures of risk factors predict substance use for all groups examined but that extremely rare behaviors are not well predicted. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Severe and early alteration of action potential during acute cardiac rejection in rats

INTRODUCTION: Alteration of cardiac action potential and its adaptation to heart rate could contribute to cardiac dysfunction and arrhythmias during acute cardiac rejection. METHODS AND RESULTS: Heterotopic heart transplantation was performed in allogeneic and syngeneic rats in which the action potentials of right and left ventricles were measured at 1, 2.5, 3.3, and 5.7 Hz successively using standard microelectrode techniques and compared with nontransplanted hearts. For each frequency, we measured action potential amplitude, action potential duration, transmembrane resting potential, and Vmax. In the right ventricle, at 1 Hz in the presence of rejection (n = 40), a significant increase was observed in action potential duration at 20%, 50%, and 70% repolarization (82.5%, 75.6%, and 70.8%, respectively) and in action potential amplitude (+17.9 mV), and the resting potential was decreased (-5.3 mV). A lack of adaptation of action potential duration to the driving frequency was observed in the rejecting heart group in contrast to controls (n = 20) and nonrejecting hearts (n = 13). Similar results were observed in the left ventricle and surprisingly in the native hearts (n = 11) of recipients with allografted rejecting hearts in the abdominal position. CONCLUSION: Action potential and its adaptation to the driving frequency is considerably altered during acute rejection. A humoral factor could contribute to cardiac dysfunction.     

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.     

Gender differences in the activities of aspirin-esterases in rat tissues

The activities of aspirin (acetylsalicylic acid)-esterases were measured in several tissues (liver, kidney, adrenal glands, brain and serum) from adult male and female Wistar rats. In males, both aspirin-esterase I (assayed at pH 5.5) and II (assayed at pH 7.4) activities were higher in liver homogenates when compared to females (aspirin-esterase I: males 48.9 +/- 4.8 (N = 8) and females 29.3 +/- 4.2 (N = 8) nmol of salicylic acid formed min-1 mg protein-1; aspirin-esterase II: males 41.4 +/- 4.1 (N = 8) and females 26.1 +/- 4.5 (N = 8) nmol of salicylic acid formed min-1 mg protein-1, P < 0.001). In serum, enzyme activity was higher in females than in males (aspirin-esterase I: males 0.85 +/- 0.06 (N = 6) and females 1.18 +/- 0.11 (N = 6) nmol of salicylic acid formed min-1 mg protein-1, aspirin-esterase II: males 1.03 +/- 0.13 (N = 6) and females 1.34 +/- 0.11 (N = 6) nmol of salicylic acid formed min-1 mg protein-1, P < 0.001). In the other tissues assayed, no statistically significant difference between males and females was found. There were no statistically significant differences when the enzymes were assayed in different phases of the estrous cycle in liver and serum. These results show that the differences in aspirin-esterase activity observed between males and females are not due to the estrous cycle. The gender difference obtained in our study may indicate an involvement of gonadal hormones in the control of the hydrolysis of aspirin. This possibility is currently under investigation.