Reduced Circulating Androgen Levels After Gastric Bypass Surgery in Severely Obese Women

Background

Previous studies have shown a reduction of elevated androgen levels in premenopausal women after marked weight loss induced by bariatric surgery. In this study, we aimed to assess whether circulating androgen levels also decline after bariatric surgery in women displaying normal values preoperatively as well as in postmenopausal women.

Methods

In 36 severely obese women (six postmenopausal), levels of total testosterone, dehydroepiandresterone sulfate (DHEA-S), and sex hormone-binding globulin (SHBG) were assessed before and at ~1 year after gastric bypass. Free and bioavailable testosterone levels as well as the free androgen index were calculated by established formulas.

Results

After the surgery, women had lost on average 43.1?±?1.8 kg. Independently of the pre/postmenopausal state, women showed a marked reduction in all testosterone-related androgen markers and DHEA-S levels, while SHBG levels markedly increased (all P?<?0.001). Respective changes were found in both women with and without preoperatively elevated levels. Changes after the surgery in testosterone-related markers as well as in SHBG levels but not in DHEA-S levels were correlated with changes in insulin levels independently of body weight changes.

Conclusions

Data show a marked reduction of androgen levels in severely obese women after a surgically induced weight loss, which is independent from the menopausal state and preoperative levels. The mechanisms and consequences of these hormonal changes induced by bariatric surgery should be addressed in further studies.     

Omnidirectional displacements for deformable surfaces

Deformable surface models are often represented as triangular meshes in image segmentation applications. For a fast and easily regularized deformation onto the target object boundary, the vertices of the mesh are commonly moved along line segments (typically surface normals). However, in case of high mesh curvature, these lines may not intersect with the target boundary at all. Consequently, certain deformations cannot be achieved. We propose omnidirectional displacements for deformable surfaces (ODDS) to overcome this limitation. ODDS allow each vertex to move not only along a line segment but within the volumetric inside of a surrounding sphere, and achieve globally optimal deformations subject to local regularization constraints. However, allowing a ball-shaped instead of a linear range of motion per vertex significantly increases runtime and memory. To alleviate this drawback, we propose a hybrid approach, fastODDS, with improved runtime and reduced memory requirements. Furthermore, fastODDS can also cope with simultaneous segmentation of multiple objects. We show the theoretical benefits of ODDS with experiments on synthetic data, and evaluate ODDS and fastODDS quantitatively on clinical image data of the mandible and the hip bones. There, we assess both the global segmentation accuracy as well as local accuracy in high curvature regions, such as the tip-shaped mandibular coronoid processes and the ridge-shaped acetabular rims of the hip bones.     

Immediate versus conventional loading of palatal implants in humans: a first report of a multicenter RCT

This study aims to analyze the clinical performance of two loading concepts on second-generation palatal implants (Orthosystem, Straumann, Basel, Switzerland) in a prospective multicenter randomized controlled clinical trial. At the time of this interim analysis, 41 patients have been randomized on a 1:1 basis to one of two treatment groups. Group 1 underwent conventional loading of palatal implants after a healing period of 12 weeks (gold standard) while group 2 underwent immediate implant loading within 1 week after implant insertion. We report initial results at 6 months after functional loading. The primary outcome parameter was implant success (no implant mobility, no implant loss). The implants in both groups were initially stable at the time of insertion, and all were eligible for randomization. Twenty-two patients (group 1) were subjected to conventional implant loading after 12 weeks while 19 patients (group 2) received immediate functional loading within the first week after insertion. Direct (e.g. distal jet appliances) as well as indirect forms of anchorage (conventional or modified transpalatal arch) were used. The magnitude of orthodontic forces ranged between 1 and 4 N for the immediate loading group and between 1 and 5 N for the conventional loading group. One implant in group 1 was lost during the healing phase. One dropout was registered in group 2. Thirty-nine implants were functionally loaded for over 6 months now. These preliminary data provide first evidence of the fact that immediate loading of palatal implants yields equivalent success rates as conventional loading to 4 N after 6 months.     

Use of a serum-free medium for long-term storage of human corneas. Influence on endothelial cell density and corneal metabolism

BACKGROUND: The success of long-term corneal organ culture is limited by the progressive loss of endothelial cells during culture and the use of culture medium supplemented with fetal calf serum as a possible source of contamination with infectious agents. In this study, we investigated the suitability of a serum-free medium (Endothelial-SFM) to improve preservation conditions for human donor corneas. METHODS: Six pairs of corneas were stored in Minimum Essential Medium (MEM) supplemented with 2% fetal calf serum (FCS) for 8-14 days. One cornea of each pair was then further cultivated in Endothelial-SFM supplemented with 2% FCS or in MEM with 2% FCS, respectively. In a second series of experiments, the endothelial cell density of seven pairs of freshly isolated donor corneas was determined during cultivation in Endothelial-SFM with 2% FCS or serum-free Endothelial-SFM. RESULTS: After precultivation in conventional medium, the endothelial cell density of corneas allocated to cultivation in Endothelial-SFM was 1000-1950 cells/mm2 and that of those subsequently cultured in MEM 1200-2000 cells/mm2. At 9 weeks, cell densities of 900-1500 cells/mm2 were found after cultivation in Endothelial-SFM compared with a total cell loss in MEM. Freshly isolated corneas cultured in Endothelial-SFM with or without FCS supplementation showed a decrease of endothelial cell density of about 20% within the first 2 weeks of storage. During further cultivation cell density remained constant without statistically significant differences between the groups. Glucose consumption of the corneas was higher in Endothelial-SFM than in MEM. Corneas stored in Endothelial-SFM with 2% FCS showed a higher glucose consumption than those preserved in serum-free Endothelial-SFM. CONCLUSION: Organ culture of human donor corneas using the serum-free basal medium Endothelial-SFM is superior to conventional culture conditions because the decrease in endothelial cell density can be ameliorated, the culture period can be prolonged and the risk of transmitting infectious agents via serum can be minimised.