Heterozygosity and retention of ejaculatory reflex after castration in male mice.

10 genotypes were used as quantified independent variables to test the hypothesis that degree of heterozygosity is associated with retention of the ejaculatory reflex after castration in 156 male mice. The hypothesis was supported when a significant positive correlation was found between percent heterozygosity and days to last postcastrational ejaculatory reflex. However, results also indicate that unknown environmental factors contribute importantly to the variance. Findings are discussed in terms of environmental and intra- and interspecific genetic variables affecting the trait. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of castration and exogenous testosterone supplementation in an animal model of penile erection

The dependence of erectile behavior on androgen functioning is well established. Castration produces loss of both libido and potency in man and animals. The present study, using an animal model for potency, demonstrates the dependence of centrally induced erectile behavior on an intact androgen milieu. Castrated rats failed to produce an erection in response to apomorphine, an agent shown to produce erection in nearly all normal rats. Administration of exogenous testosterone propionate in dosages exceeding 60 micrograms./kg. produced a significant increase in erectile behavior. Yawning, an essentially parallel phenomenon to the stimulation of the erectile response, was also decreased following castration and responded similarly to increasing amounts of exogenous testosterone, demonstrating the influence of androgen functioning on the central nervous system. It was concluded that testosterone is a necessary prerequisite for the maintenance of a centrally induced erectile and yawning response. In an animal model of penile erection, testosterone increases the number of erections in a dose-dependent manner in castrated rats. The dependence of the erectile response on testosterone is, at least in part, centrally mediated.     

Neonatal castration and adult responsiveness to testosterone in male rats: an interstrain comparison

We have previously demonstrated that the spontaneously hypertensive rat (SHR) has a lower central nervous responsiveness to testosterone than its normotensive counterpart the Wistar-Kyoto rat (WKY). The adult psychoendocrine response capacity depends on a neonatal testosterone surge. On that basis, we compared the effects of neonatal endocrine manipulation on the adult responsiveness to testosterone in the SHR, WKY, and yet another breed of Wistar (Wi) male rats. Interstrain differences in testosterone-induced copulatory behavior at three different doses of testosterone propionate (TP) were investigated. Neonatal treatments were as follows: TP (0.25 mg/animal) given on postnatal days (PND) 0, 2, and 4 (SHR and Wi only) or castration PND 0, 10, or 50. Neonatal TP treatment impaired copulatory performance in the adult SHR but not in the Wi. Neonatal castration improved the responsiveness to TP in the SHR but less so in WKY, whereas no evident effects were seen in the Wi. No significant interstrain differences in plasma testosterone were observed 2, 6-12, or 24 h postpartum. The demonstrated interstrain differences suggest not only that the adult responsiveness to testosterone is established on the basis of the neonatal gonadal secretion as such but that this secretion is kept to an optimal level with respect to subsequent hormone-sensitive mechanisms.     

Sexual behavior and alpha-2 adrenoreceptors in the neocortex of male rats after castration and testosterone administration

Castration of male rats inhibited their sexual behaviour and increased the density of the alpha-2 adrenergic receptors in the brain cortex. Treatment of castrated or intact males with testosterone activated their sexual behaviour and decreased the receptor density in the brain cortex. The obtained evidence testify to the involvement of the brain alpha-2 adrenergic receptors in the effect of testosterone on male sexual behaviour.     

Expression of glutathione-peroxidase (GSH-PO) in the rat ventral prostate--effect of castration and administration of testosterone

This series retrospectively reviewed 3657 patients who received thyroid ultrasonography with fine-needle aspiration cytological (FNAC) examinations at Chang Gung Memorial Hospital during the period from January 1, 1993 to December 31, 1993. Thyroid ultrasonography studies were performed using a real-time ultrasonographic machine with a 10 MHz transducer. The aspirates were air dried and stained by the Romanowsky-based Liu method. Three hundred seventy-eight cases (10.3%) received surgical treatment after the ultrasonographic and FNAC examinations. Benign lesions were diagnosed in 269 patients. Thyroid malignancy was confirmed histopathologically in 109 cases including 76 papillary thyroid carcinomas, 17 follicular carcinomas, 5 medullary thyroid carcinomas, 3 anaplastic carcinomas, 3 Hürthle cell carcinomas, and 3 lymphomas. Another 2 cases were metastatic cancer to thyroid. The results demonstrated that 28.8% of the surgically treated patients had histopathologically proven malignancies. The incidence of thyroid malignancy was 2.98% in this study. The sensitivity of the cytological diagnosis was 79.80% and the specificity was 98.66%. The positive predictive value was 96.34%. Negative predictive value was 91.70%. The false negative index was 20.20%. The diagnostic accuracy was 92.89%. Thyroid ultrasonography with the FNAC can provide high specificity and sensitivity in differentiating malignant lesions from benign.     

Neuroimaging and neurobiological models of depression

We review the data from structural neuroimaging studies (computed tomography and magnetic resonance imaging) related to depressive disorders. In addition, we review the relevant functional neuroimaging research, including studies of normal emotional processing, studies of the functional neuroanatomy of major depression, and neurochemical neuroimaging studies of depression. Finally, we discuss existing neurobiological models of depression and offer modifications based upon the body of neuroimaging research we have presented.     

Appraisal of the self-schema construct in cognitive models of depression.

Discusses the role of self-schemata in cognitive models of depression and evaluates the empirical support for this notion according to criteria consonant with this construct's usage in cognitive psychology and social cognition. Whereas the concept of a negative self-schema was initially proposed as a distal cognitive diathesis to depressive disorder, measurement problems have hindered a meaningful test of this construct's predictive capacity. Furthermore, conceptual and design-related confounds in extant depressive-schema studies prevent the demonstration of schematic processing independent of the effects of depressed mood on the dependent variables used. It is argued that reconceptualizing self-schema in cognitive-structural terms may help address and resolve some of these current problems. For example, methods used to assess more general knowledge structures, such as semantic networks, might be profitably used to verify whether information about the self is similarly organized. This can then begin the process of specifying the exact nature of the information thought to be stored within this structure and allow researchers to move beyond a simple dichotomy of positive and negative elements to models that better reflect the complexity of self-construal. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Predicting depressive symptomatology: Cognitive-behavioral models and postpartum depression.

170 women (mean age 26.6 yrs), seen in their 2nd trimester of pregnancy, were followed-up about 3 mo postpartum. Level of depression (Beck Depression Inventory) was just as high during pregnancy as during the postpartum period. Several variables assessed during pregnancy and during the postpartum period were significant predictors of postpartum depression level, including measures of prepartum depression, attributional style, delivery stress, and stressful life events. The predictor variables accounted for about 40% of the variance in level of postpartum depression. Predictor variables from earlier research such as history of menstrual problems, parity, education, and income did not account for significant variance in postpartum depression level. These findings provide some evidence for the role of cognitive-behavioral factors and stressful life events in depression. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Type III error in research on interpersonal models of depression.

Reviews an interactional model of depression proposed by J. C. Coyne (see PA, Vols 56:2455 and 61:1146), empirical evaluations of this model, and related research. It is contended that laboratory studies designed to test these interactional models have examined stangers' reactions to depressives and therefore have little relevance to these models, which focus on the interactional processes between a depressed individual and his/her family and friends. It is argued that relevant empirical research is necessary before theoretical conjectures and treatment strategies based on an interactional model are accepted. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Uncontrollability, depression, and the construction of mental models.

Three studies examined mental model generation after preexposure to uncontrollability and in a depressive state. The purpose of the experiments was to test the implications of the cognitive exhaustion model, applying an explicit conceptualization of social mental models and a process-tracing method developed by U. von Hecker (1997). An experimental situation was created for observation of consecutive, rule-based construction steps as a function of input diagnosticity, and for the quality assessment of constructed mental models. The findings show that participants preexposed to uncontrollability, as well as depressed students, were able, as were controls, to identify rule-relevant information needed for model construction. However, they were less able than control participants to engage in a more cognitively demanding and generative step of processing (i.e., in integrating the pieces of input information into a coherent mental model of sentiment relations). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dopamine-stimulated sexual behavior is testosterone dependent in mice

The ingestion of viable bacteria is thought to be required to modify intestinal microflora. In the present study, the effects on fecal flora of consumption of cell-free concentrated whey from milk that had been fermented with Bifidobacterium breve C50 was tested using 10 healthy human volunteers. Results were compared with effects of a commercial milk formula that had been fermented with Streptococcus thermophilus and B. breve C50 and given to 10 control subjects. Nitroreductase and beta-glucuronidase activities were assessed as risk indexes for colon carcinogenesis, and beta-galactosidase was measured as an indicator of the fermentation capacity of the colonic flora. Fecal excretion of Bacteroides fragilis, Clostridium perfringens, and clostridial spores decreased after 7 d of consumption of either preparation; however, counts of bifidobacteria only increased after intake of B. breve whey. Fecal pH was reduced from 7.1 +/- 0.2 to 6.6 +/- 0.3 after intake of whey that had been fermented with Bif. breve. Fecal nitroreductase and beta-glucuronidase significantly decreased, and beta-galactosidase activity increased, after consumption of either preparation. The results indicate that ingestion of viable bifidobacteria was not required to modify intestinal flora of humans. Repression of B. fragilis and clostridia seems to be independent of colonic bifidobacterial overgrowth in humans.     

Caregiver models of self and others, coping, and depression: Predictors of depression in children with chronic pain.

In a sample of 59 chronically ill pediatric patients and their maternal caregivers, both child-reported pain and caregiver-reported depression predicted child-reported depression. Results further suggested that the association between pain and depression in children is ameliorated by caregiver coping strategies and that how caregivers cope is a function of their attachment-related representations of the self and others. Caregivers with a negative model of the self were more depressed, and those with a negative model of others were more prone to use avoidant coping strategies, and, in turn, to be more depressed. However, the extent to which caregivers with negative models of self used more avoidant and less approach coping appeared to depend on whether they perceived that others were likely to respond to their needs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of policosanol on circulating endothelial cells in experimental models in Sprague-Dawley rats and in rabbits

The effect of policosanol on circulating endothelial cells has been studied in different experimental models with endothelium damage. Oral administration of 25 mg kg-1 policosanol to Sprague-Dawley rats resulted in significant protection of the endothelial lining against the desquamating effect of citrate. Oral administration of 5 mg kg-1 policosanol to spontaneously hypertensive rats (SHR) resulted in a significant reduction of circulating endothelial cells compared with controls. Moreover, comparison between groups revealed a lower frequency of aortic lesions in policosanol-treated animals than in controls. On the other hand, administration of 5 mg kg-1 policosanol to rabbits with intimal hyperplasia induced by cuff placement in the carotid artery resulted in levels of circulating endothelial cells significantly lower than in controls. These results demonstrate the protective effect of policosanol in different experimental models and suggest its potential for endothelial protection.     

The effects of castration and treatment with testosterone on the biliary excretion of (3H)aldosterone in rats

The rate of excretion of aldosterone radiometabolites into the bile duct cannulation, and the intravenous injection of (3H)aldosterone, was demonstrated to be markedly increased in male rats following castration. In 1 h, 72% of the injected 3H-radioactivity was excreted in the bile of castrated male rats compared with 26% in the intact male control rats. Castration of the males led to the increased biliary excretion of aldosterone metabolites and the elimination of the sex-dependence of this process in rats. The ovariectomy of female rats did not substantially increase the rate of excretion of aldosterone metabolites via the bile. Castrated male rats treated with testosterone excreted aldosterone metabolites into the bile at a slower rate. A similar treatment of ovariectomized female rats with testosterone also significantly slowed the rate of biliary excretion of the aldosterone metabolites. These findings suggest that the presence of androgens plays an important role in regulating the routes of hepatic metabolism of aldosterone and the rates of clearance of aldosterone and its metabolites from the plasma into the bile of rats.     

Steroid glucuronyltransferases of rat liver. Properties of oestrone and testosterone glucuronyltransferases and the effect of ovariectomy, castration and administration of steroids on the enzymes

1. Microsomal preparations from rat liver, kidney and intestine were tested for UDP-glucuronyltransferase activity by using oestrone, oestradiol-17 beta, oestriol, testosterone, cortisol, cortisone, corticosterone, aldosterone, tetrahydrocortisol and tetrahydrocortisone as substrates. The microsomal preparation from the liver glucuronidated oestrone, oestradiol-17 beta and testosterone. 2. The specific activity of the enzyme was significantly higher in livers from female rats than in those from male rats. 3. Testosterone was actively glucuronidated by both sexes. Cortisol, cortisone, corticosterone, aldosterone, tetrahydrocortisol and tetrahydrocortisone were not glucuronidated by any of the three tissues. 4. The non-ionic detergent Lubrol WX activates liver microsomal UDP-glucuronyltransferase 2-3-fold with oestrone and testosterone as substrates. 5. Oestrone glucuronyltransferase was inhibited by oestradiol-17 beta, predominantly competitively and by testosterone non-competitively. Bilirubin was a non-competitive inhibitor of oestrone glucuronidation. p-Nitrophenol had no effect. 6. Oestrone glucuronyltransferase could not be stimulated by either acute or prolonged treatment of animals with phenobarbital, whereas a single dose of 3-methylcholanthrene led to a moderate stimulation. 7. Ovariectomy leads to a 56% decrease in oestrone glucuronyltransferase activity; administration of oestradiol-17 beta induces the enzyme to normal activity after 12 days, and after 15 days the activity is twice the control value. Actinomycin D and cycloheximide block the oestradiol-17 beta-induced increase in enzyme activity. 8. Castration has no effect on the activity of testosterone glucuronyltransferase, nor does administration of testosterone influence enzyme activity. The results provide strong evidence for the existence of multiple steroid glucuronyltransferases in the liver of the rat.     

Sex hormones and metabolism of glycosaminoglycans. I. Effect of orchidectomy and administration of testosterone in rabbits

The effect of orchidectomy in male rabbits and administration of testosterone to orchidectomized animals on the metabolism of glycosaminoglycans (GAG) has been studied. The response of the different GAG fractions in the aorta varies with the nature of the GAG, and in some cases is different in different segments of the aorta. Orchidectomy produced an increase in hyaluronic acid fraction, decrease in heparin sulphate fraction, and no response in the chondroitin sulphate A fraction in the aortic arch, thoracic aorta, and abdominal aorta. Chondroitin sulphate C and chondroitin sulphate B fractions decreased only in the abdominal aorta and were not significantly altered in the other two segments, while heparin fraction decreased only in the thoracic aorta and was not affected in the other segments. Administration of testosterone to the orchidectomized animals counteracted these changes in the aortic GAG fractures. The enzymes concerned with the synthesis of precursors of GAG--L-glutamine:D-fructose-6-phosphate aminotransferase, UDPG dehydrogenase, and UDPG pyrophosphorylase-- all decreased in the orchidectomized animals; testosterone administration increased their activity in the orchidectomized animals. Enzymes concerned with degradation of GAG--beta-glucuronidase, beta-hexosaminidase, aryl sulphatase, cathepsin, and hyaluronidase--increased in the orchidectomized and decreased on administration of testosterone. Concentration of PAPS and activity of sulphate-activating system and sulphotransferase also decreased in the orchidectomized animals, and testosterone administration tended to restore this decrease to normal levels.     

Perceptual independence: Definitions, models, and experimental paradigms.

Necessary distinctions in an analysis of the study of perceptual independence are: (1) between the definition of independence as zero correlation and its definition as performance parity, (2) between normative models of perceptual process and models of perceptual state, and (3) between experimental designs which use orthogonal stimulus inputs and those which use correlated inputs. Implications of this analysis are: (1) perceptual independence is not a unitary concept; (2) it can be studied most effectively with experiments using orthogonal inputs; (3) when correlated stimulus inputs are used, so many underlying assumptions have to be made that it is almost impossible not to find a model which satisfies both the concept of independence and any given experimental result; (4) state independence is intimately related to process independence; and (5) search for the locus of interaction is probably a more useful approach than trying to determine whether independence exists. (29 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceptions of stressful life events and depression: A test of attributional models.

Tested the attributional models of depression proposed by L. Y. Abramson et al (see record 1979-00305-001), using 278 undergraduates who had recently experienced a stressful event and 51 55–79 yr old adults who sought treatment for problems with depression. Three questions were addressed: (a) the validity of the hypothesized independent and direction relation between each of the dimensions of internality, stability, controllability, intentionality, and globality and depression; (b) the causal relation between attributions and depression in a 2-mo prospective study; and (c) evaluation of the model on the 2 disparate samples. Ss were administered a battery of depression measures; students completed an attribution questionnaire, while adults completed a measure of life stress attributions. Causal modeling statistical procedures were applied to both the question of concurrent relations and causal relations between cognitions and depression. Results suggest minimal support for the attributional model: The dimensions were not each independently and directly associated with depression in the manner predicted, and the model that best fit the data was generally congruent for both the normal and clinical samples. In terms of direction of causality, the data were more consistent in indicating that depression causes cognitions than in indicating the reverse. (45 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)