Physico-Chemical Characterization of the Soluble 3α-Hydroxysteroid Oxidoreductase in the Rat Testis and Prostate

The present paper describes some physicochemical properties of the soluble 3α-oxidoreductases in the rat testis and prostate, and comparison with rat epididymal 3α-oxidoreductase, published previously (Hastings & Hansson 1979). The testicular enzyme shows properties very similar to that in the epididymis (size, stability, pH optium) except for minor differences in charge (iso-electric point). The prostatic enzyme revealed a slightly higher molecular weight, and was more sensitive to heating than those in the testis and epididymis, whereas the iso-electric point was the same as that in the testis (pI-5.25). The enzymes in all tissues exhibit very similar shapes (f/fo 1.14-1.17).
The similar properties of the testicular and prostate 3α-oxidoreductases to those previously reported for that in the epididymis may indicate that these enzymes represent identical peptide chains. The small differences observed in size, temperature stability and change may be due to their presence in different environments.     

Junctional complexes in the preimplantation rabbit embryo.

The morphology and development of junctional complexes between blastomeres of the preimplantation rabbit embryo were investigated using several approaches. Electron microscopic examination of embryos stained en bloc with uranyl acetate, and the study of junction permeability using horseradish peroxidase and lanthanum nitrate provided information on structure, intermembrane spacing and permeability of the junctional complexes. In addition, the freeze fracture technique was used with day 5 and day 6 blastocysts, since the large size of these embryos facilitated use of this method. These experiments showed that although rudimentary junctions were present between blastomeres of the early cleavage stages, effective tight junctions were not present until the blastocyst stage. Electron microscopic examination of thin sections revealed apical foci of membrane approximation or "fusion" between trophoblast cells by day 4. Freeze fracturing revealed a lattice of interconnecting ridges (on the A face) and grooves (on the B face) in the apical region between trophoblast cells of the day 5 blastocyst. This lattice formed a continuous band along the apical margin of each cell, and therefore constituted a zonula occludens. The zonula occludens of the day 5 blastocyst averages 2-3 ridges per lattice, while day 6 blastocysts had lattices that averaged 5-6 ridges. Also seen in the freeze fracture replicas from the day 5 and day 6 blastocysts were local accumulations of intramembranous particles on the A face. These particles were often observed in aggregates similar to those of previously described gap junctions. It could not be determined whether these small regions of particles were true gap junctions or a possible primitive form of gap junction because the complementary pitted surfaces (B face pits) were not demonstrated.     

Longitudinal relations between child vagal tone and parenting behavior: 2 to 4 years

The longitudinal relations between physiological markers of child emotion regulation and maternal parenting practices were examined from 2 to 4 years of age. At Time 1, cardiac vagal tone was assessed for one hundred four 2-year-olds (54 females); their mothers completed an assessment of parenting styles. Two years later, at Time 2, 84 of the original participants were reassessed on measures of cardiac vagal tone and parenting style. Results indicated both baseline cardiac vagal tone and maternal parenting practices to be stable from 2 to 4 years of age. Children's cardiac vagal tone predicted specific parenting practices from the toddler to preschool years. Further, child cardiac vagal tone moderated maternal restrictive-parenting practices from 2 to 4 years of age; mothers of children who were highly or moderately physiologically dysregulated were more likely to report restrictive parenting practices at both 2 and 4 years of age.     

Parathyroid hormone-related protein and lung biology

Parathyroid hormone-related protein (PTHrP) is expressed in normal and malignant lung and has roles in development, homeostasis, and pathophysiology of injury and cancer. Its effects in developing lung include regulation of branching morphogenesis and type II cell maturation. In adult lung, PTHrP stimulates disaturated phosphatidylcholine secretion, inhibits type II cell growth, and sensitizes them to apoptosis. In lung cancer, PTHrP may play a role in carcinoma progression, or metastasis. The protein could be a useful marker for assessing lung maturity or type II cell function, predicting risk of injury, and detecting lung cancer. PTHrP-based therapies could also prove useful in lung injury and lung cancer.     

Positive perceptions held by support staff in community mental retardation services

Existing research on support staff has been focused on variables associated with stress. However, there has been little attention to the possibility that staff may also experience a number of positive outcomes or perceptions. In the present study, 101 support staff working with adults who had mental retardation completed measures of burnout and mental health and a new measure: the Staff Positive Contributions Questionnaire (SPCQ). A range of positive perceptions of their work was endorsed by participants, demonstrating that such perceptions do exist and require theoretical explanation. The SPCQ had promising internal consistency, test-retest reliability, and construct validity. Thus, further research with this instrument is warranted.     

Microglial activation precedes dopamine terminal pathology in methamphetamine-induced neurotoxicity

Previous studies have demonstrated methamphetamine (METH)-induced toxicity to dopaminergic and serotonergic axons in rat striatum. Although several studies have identified the nature of reactive astrogliosis in this lesion model, the response of microglia has not been examined in detail. In this investigation, we characterized the temporal relationship of reactive microgliosis to neuropathological alterations of dopaminergic axons in striatum following exposure to methamphetamine. Adult male Sprague-Dawley rats were administered a neurotoxic regimen of methamphetamine and survived 12 h, or 1, 2, 4, and 6 days after treatment. Immunohistochemical methods were used to evaluate reactive changes in microglia throughout the brain of methamphetamine-treated rats, with a particular focus upon striatum. Pronounced morphological changes, indicative of reactive microgliosis, were evident in the brains of all methamphetamine-treated animals and were absent in saline-treated control animals. These included hyperplastic changes in cell morphology that substantially increased the size and staining intensity of reactive microglia. Quantitative analysis of reactive microglial changes in striatum demonstrated that these changes were most robust within the ventrolateral region and were maximal 2 days after methamphetamine administration. Analysis of tissue also revealed that microglial activation preceded the appearance of pathological changes in striatal dopamine fibers. Reactive microgliosis was also observed in extra-striatal regions (somatosensory and piriform cortices, and periaqueductal gray). These data demonstrate a consistent, robust, and selective activation of microglia in response to methamphetamine administration that, at least in striatum, precedes the appearance of morphological indicators of axon pathology. These observations raise the possibility that activated microglia may contribute to methamphetamine-induced neurotoxicity.     

Salivary testosterone diurnal variation and psychopathology in adolescent males and females: individual differences and developmental effects

Individual differences in salivary testosterone were examined in 213 adolescents (106 boys, 107 girls; mean age = 13.66 years) in relation to externalizing and internalizing psychopathology. Self- and parent-report measures of behavior problems and psychiatric symptoms were obtained. Latent anxiety-depression, disruptive behavior, and attention problem constructs were developed using multitrait, multimethod procedures. Saliva samples were collected in the morning, midday, and late afternoon on multiple days and were later assayed for testosterone. Latent constructs were derived for testosterone level and diurnal variation across the six sampling occasions. Structural equations modeled relationships between problem behavior and intra- and interindividual differences in testosterone separately by gender. For boys, lower levels of testosterone and testosterone levels that decreased more slowly across the day were related to higher levels of anxiety-depression and attention problems. These associations were not moderated by pubertal development. For girls, steep declines in testosterone production across the day related to higher levels of disruptive behavior problems, but this association was only evident after including pubertal development as a moderator in the model. These findings raise novel questions regarding the nature and magnitude of links between testosterone and problem behavior in youth.     

'They look like my kind of people'--perceptions of smoking images in youth magazines

Ten years ago research showed that pro-smoking images were prevalent in British youth magazines, whereas there was little coverage of smoking and health. Since then there has been a great expansion in the number of youth magazines, and particularly those aimed at young men. Titles such as FHM and Loaded, which did not exist at the time of the previous research, are now market leaders. New qualitative and quantitative research has therefore been conducted to examine the prevalence and impact of smoking images in this revitalised youth style magazines market. This paper presents the findings of the qualitative element of this research, which examined British first year students' perceptions of the pro-smoking imagery found in the magazines and explored the relationship between this and their own smoking images and identities. The research found that: (a) this imagery was perceived to be, on the whole, attractive, sociable and reassuring; (b) that it supported young people's perceptions of smoking and reinforced their smoker identities; and (c) that it has the potential to be more powerful than advertising imagery.