Effects of estrogen deprivation on human benign prostatic hyperplasia

Sex steroids are thought to play an essential role in the pathogenesis of human benign prostatic hyperplasia (BPH). Since recent studies in animal models and in men have shown that estrogens might be causally linked to the onset and maintenance of BPH, we examined the effect of 1-methyl-androsta-1,4-diene-3,17-dione (Atamestane), a newly developed aromatase inhibitor, in men with BPH. In an open multicenter study 49 men (mean age 70.1 years, range 55 to 84) with obstructive BPH were treated with atamestane (3 × 200 mg/day) for 3 months. Of the 49 patients 44 completed the treatment period; the other patients discontinued the study for reasons unrelated to treatment. With treatment BPH-related symptoms such as daytime voiding frequency, nycturia, peak flow and residual urine improved considerably; however, these parameters did not reach statistical significance. The mean prostatic volume decreased significantly from 74.2 ± 31.7 to 64.0 ± 31 ml (mean ± SD). Serum estrogen levels decreased markedly during treatment. In addition intraprostatic estrogen concentration decreased with treatment as compared to estrogen levels in hyperplastic prostates from untreated patients. The following conclusions can be drawn from this study: first, estrogens appear to have an important supportive role in established BPH, and second, estrogen deprivation improved BPH-related symptoms and reduced significantly prostatic volume.     

Basal and stimulated hyperinsulinemia in obesity: relationship to adipose-cell size.

In 17 non-selected, non-hyperlipoproteinemic subjects without overt diabetes both adipose tissue biopsy and an oral glucose tolerance test (50 g) were performed. All persons were weight-stable at the time of investigation. A significant correlation between fasting insulin concentration and mean adipocyte volume was observed, whereas no correlation existed between ideal body weight index and fasting insulin level. Persons with larger adipocytes had elevated basal insulin levels as well as higher and longer lasting increments following the glucose challenge. They also exhibited significantly higher mean glucose levels during the OGTT. When these patients were matched for glucose tolerance with the subgroup having smaller mean adipocyte volumes, the difference in insulin levels was still demonstrable. This study underlines the importance of adipose-cell enlargement regulating basal and stimulated insulin output.     

Evidence for changes in the conformational status of rat liver microsomal glucose-6-phosphate:phosphohydrolase during detergent-dependent membrane modification. Effect of p-mercuribenzoate and organomercurial agarose gel on glucose-6-phosphatase of native and detergent-modified microsomes

Comparative studies investigating influences of temperature and time of preincubation on the interactions of an organomercurial agarose gel and p-mercuribenzoate with glucose-6-phosphatase of native and Triton X-114-modified rat liver microsomes were carried out. The effect of p-mercuribenzoate on glucose 6-phosphate hydrolysis is a result of two processes, a moderate membrane perturbation connected with release of some latency and temperature- and time-dependent inhibition of the catalytic activity. Short-term preincubation with both organic mercurials at 37 degrees C is a necessary condition for the entire inhibition of the enzyme activity of native as well as of Triton X-114-modified microsomes. A binding site of the phosphohydrolase itself is accessible to p-mercuribenzoate and the phenyl mercury residue of the affinity gel from the cytoplasmic surface even in native microsomes. Kinetic analyses reveal a formally competitive mechanism of inhibition using native microsomes, but the kinetic picture changes to a noncompetitive pattern of Lineweaver-Burk plots when the inhibitor-loaded microsomes are modified optimally by Triton X-114. This behavior can be evaluated as the first convincing evidence for drastic changes of the conformational status of the phosphohydrolase during the membrane modification process. A combined conformational flexibility-substrate transport model characterizing the microsomal glucose-6-phosphatase as an integral channel-protein embedded within the hydrophobic interior of the membrane is proposed.     

Environmental regulation of surface conductance for evaporation from vegetation

We examine conductances for evaporation from both vegetation and soil in response to environmental variables. Data from a vertically-structured pristine forest of Nothofagus are presented as an example of the effects of biodiversity on the scaling of conductances between tiers of plant organisation. Available data sets of maximum leaf stomatal conductances (g _lmax ) and bulk vegetation surface conductances (G _smax ) are compared. Overall, the ratio G _smax /g _lmax is consistently close to 3 for seven major vegetation types of diverse structure. An analytical model accounts for this close relationship, and in particular how G _smax is conservative against changes in leaf area index because of the compensating decrease in plant canopy transpiration and increase in soil evaporation as leaf area index diminishes. The model is also successfully tested by comparison with canopy conductances of emergent trees measured in the Nothofagus forest. The constraint of vegetation surface conductance and evaporation via environmental regulation by irradiance, air saturation deficit and root zone water supply are discussed.     

Voxel-Based Morphometry in Women with Borderline Personality Disorder with and without Comorbid Posttraumatic Stress Disorder

Patients with Borderline Personality Disorder (BPD) showed reduced volume of amygdala and hippocampus, but similar findings are evident in Posttraumatic Stress Disorder (PTSD). Applying voxel-based morphometry (VBM) in a larger cohort of patients with BPD, we sought to extend earlier findings of volume abnormalities in limbic regions and to evaluate the influence of co-occurring PTSD in BPD patients. We used voxel-based morphometry to study gray matter volume (GMV) in 60 healthy controls (HC) and 60 patients with BPD. Subgroup analyses on 53 patients concerning the role of co-occurring PTSD were conducted. Additionally, regression analyses were calculated to assess the relation between borderline symptom severity as well as dissociative experiences and GMV. Differences in local GMV between patients with BPD and HC were observed in the amygdale and hippocampus as well as in the fusiform and cingulate gyrus. Co-occurring PTSD was accompanied by increased GMV in the superior temporal gyrus and dorsolateral prefrontal cortex. Independent of co-occurring PTSD, severity of BPD symptoms predicted smaller GMV in the amygdala and dorsal ACC. Dissociation was positively related to GMV in the middle temporal gyrus. We could replicate earlier findings of diminished limbic GMV in patients with BPD and additionally show that patients with co-morbid PTSD feature increased GMV in prefrontal regions associated with cognitive control.