Clinical Predictors of Sleep Apnea in Patients Undergoing Bariatric Surgery

Background: Sleep apnea is a frequent and unappreciated condition of morbidly obese patients. If unrecognized it could lead to significant postoperative complications. A clinical tool to assess the severity of sleep apnea is not available.We prospectively determined whether the Epworth Sleepiness Scale (ESS) or body mass index (BMI) predict the severity of sleep apnea in morbidly obese patients. Methods: 66 consecutive patients evaluated for bariatric surgery from June to November 1999 were examined and prospectively administered a health questionnaire including the ESS. Patients with an ESS ≥ 6 were referred for polysomnography with calculation of Respiratory Disturbance Index (RDI). Sleep apnea was graded as mild (RDI 6-20), moderate (RDI 21-40) and severe (RDI>40). Clinical variables such as BMI and ESS score were compared using regression analysis. Data are mean ± SEM. Results: 4 men and 23 women (27/66) who scored >6 on the ESS completed a sleep study. Mean ESS was 13 ± 4.5. Sleep apnea was mild in 13 patients, moderate in 7, severe in 6, and absent in 1. Mean age was 43 ± 9.5 years. BMI was 52 ± 10 kg/m². Linear regression analysis did not demonstrate correlation between ESS score and severity of sleep apnea (r²=0.03, p>0.05). Multiple regression analysis demonstrated no correlation between BMI, patient snoring, and RDI score. Conclusions: Sleep apnea is frequent in candidates screened for bariatric surgery. ESS is a useful tool to investigate daytime sleepiness and other manifestations of sleep apnea. However, the ESS does not predict the severity of sleep apnea. Clinical suspicion of sleep apnea should prompt polysomnography.     

Simulated increases in body fat and errors in bone mineral density measurements by DXA and QCT

Major alterations in body composition, such as with obesity and weight loss, have complex effects on the measurement of bone mineral density (BMD) by dual‐energy X‐ray absorptiometry (DXA). The effects of altered body fat on quantitative computed tomography (QCT) measurements are unknown. We scanned a spine phantom by DXA and QCT before and after surrounding with sequential fat layers (up to 12 kg). In addition, we measured lumbar spine and proximal femur BMD by DXA and trabecular spine BMD by QCT in 13 adult volunteers before and after a simulated 7.5 kg increase in body fat. With the spine phantom, DXA BMD increased linearly with sequential fat layering at the normal (p < 0.01) and osteopenic (p < 0.01) levels, but QCT BMD did not change significantly. In humans, fat layering significantly reduced DXA spine BMD values (mean ± SD: ?2.2 ± 3.7%, p = 0.05) and increased the variability of measurements. In contrast, fat layering increased QCT spine BMD in humans (mean ± SD: 1.5 ± 2.5%, p = 0.05). Fat layering did not change mean DXA BMD of the femoral neck or total hip in humans significantly, but measurements became less precise. Associations between baseline and fat‐simulation scans were stronger for QCT of the spine (r² = 0.97) than for DXA of the spine (r² = 0.87), total hip (r² = 0.80), or femoral neck (r² = 0.75). Bland‐Altman plots revealed that fat‐associated errors were greater for DXA spine and hip BMD than for QCT trabecular spine BMD. Fat layering introduces error and decreases the reproducibility of DXA spine and hip BMD measurements in human volunteers. Although overlying fat also affects QCT BMD measurements, the error is smaller and more uniform than with DXA BMD. Caution must be used when interpreting BMD changes in humans whose body composition is changing. © 2012 American Society for Bone and Mineral Research     

Psychosocial Functioning following Bariatric Surgery

Morbid obesity is associated with an increased risk of morbidity and mortality as well as psychosocial problems and poor quality of life. The ultimate goal of bariatric surgery is not only reduced weight and reduction of co-morbidities, but also improved psychosocial functioning and quality of life. However, not all patients are successful. A systematic literature search of recent articles identified relevant variables reflecting postoperative psychosocial functioning. Most studies showed that bariatric surgery does not only lead to substantial weight reduction, but also to improvement or cure of physical as well as psychological co-morbidities. Although most studies are optimistic and report broad psychosocial improvement, a significant minority of patients do not benefit psychologically from surgery. Although there are mixed results, the overall improvements in psychosocial functioning provide additional justification for surgical treatment of morbid obesity.     

In Vitro Biocompatibility of New PVA-Based Hydrogels as Vitreous Body Substitutes

In order to synthesize injectable hydrogels suitable as vitreous body substitutes, a new method based on the use of trisodium trimetaphosphate (STMP) to cross-link PVA was recently proposed. Hydrogels with different molar ratios between STMP and PVA were realised. The aim of the present study was the evaluation of the biocompatibility of the different STMP/PVA hydrogels synthesised by analysing the effects of their in vitro interaction with cultures of mouse fibroblasts NIH3T3, primary human microvascular endothelial cells adult (HMVECad) and human lens cells. Cytotoxicity of hydrogels was first evaluated by analysing cell density and proliferation. Morphological and morphometric analysis of cell in contact with hydrogels was then performed using light microscopy and scanning electron microscopy, respectively. Moreover, cell adhesion and growth onto the hydrogels surface was evaluated and correlated to the amount of adsorbed proteins. At last, the biocompatibility of the sheared STMP/PVA 1:8 hydrogel was tested. The in vitro data of all the STMP/PVA hydrogels demonstrated their good biocompatibility, and indicated that the 1:8 sample was the most promising as vitreous body substitute.     

The role of vitamin D in improving physical performance in the elderly

There is an ongoing debate over the role of serum 25(OH) vitamin D [25(OH)D] levels in maintaining or improving physical performance and muscle strength. Much of the controversy is because of the variability between studies in participants' characteristics, baseline serum 25(OH)D levels, and baseline physical functioning. The aim of this ancillary study conducted within a randomized controlled clinical trial was to investigate whether supplementation with 400 or 2000 IU vitamin D₃ daily for 6 months would improve measures of physical performance and muscle strength in a community‐dwelling elderly population aged 65 to 95 years. Those with the slowest gait speed improved their ability to do chair‐stand tests after vitamin D supplementation. This finding remained significant after controlling for potential confounding variables. There was also an inverse correlation between serum 25(OH)D levels and fat mass index (FMI) among women, suggesting that higher supplementation with vitamin D is needed as weight increases. The results of this study suggest that supplementation with vitamin D may be most beneficial in older populations who have low baseline physical functioning. © 2013 American Society for Bone and Mineral Research.     

Rapid Mineralization of Electrospun Scaffolds for Bone Tissue Engineering

We investigated different techniques to enhance calcium phosphate mineral precipitation onto electrospun poly(_L-lactide) (PLLA) scaffolds when incubated in concentrated simulated body fluid (SBF), 10×SBF. The techniques included the use of vacuum, pre-treatment with 0.1 M NaOH and electrospinning gelatin/PLLA blends as means to increase overall mineral precipitation and distribution throughout the scaffolds. Mineral precipitation was evaluated using environmental scanning electron microscopy, energy dispersive spectroscopy mapping and the determination of the mineral weight percents. In addition we evaluated the effect of the techniques on mechanical properties, cellular attachment and cellular proliferation on scaffolds. Two treatments, pre-treatment with NaOH and incorporation of 10% gelatin into PLLA solution, both in combination with vacuum, resulted in significantly higher degrees of mineralization (16.55 and 15.14%, respectively) and better mineral distribution on surfaces and through the cross-sections after 2 h of exposure to 10×SBF. While both scaffold groups supported cell attachment and proliferation, 10% gelatin/PLLA scaffolds had significantly higher yield stress (1.73 vs 0.56 MPa) and elastic modulus (107 vs 44 MPa) than NaOH-pre-treated scaffolds.     

Rho GTPase protein expression and activation in murine monocytes/macrophages are not modulated by model biomaterial surfaces in serum-containing in vitro cultures

The Rho GTPase cellular signaling cascade was investigated in pro-monocyte and (monocyte-)macrophage cells by examining GTPase expression and activation in serum-containing cultures on model biomaterials. Abundance of Rho GDI and the Rho GTPase proteins RhoA, Cdc42 and Rac1 was determined in cells grown on tissue-culture polystyrene, polystyrene, poly-L-lactide and Teflon^® AF surfaces. Protein expression was compared based on cell maturity (pro-monocyte to monocyte to macrophage lineages) and by model surface chemistry: Rho proteins were present in the majority of macrophage cells tested on model surfaces suggesting that a pool of Rho proteins is readily available for signaling events in response to numerous activating cues, including biomaterials surface encounter. Rho GTPase activation profiles in these cell lines indicate active Cdc42 and Rho proteins in RAW 264.7, Rac1 and Rho in J774A.1, and Cdc42 and Rac1 in IC-21 cell lines, respectively. Collectively, these proteins are known to play critical roles in all actin-based cytoskeletal rearrangement necessary for cell adhesion, spreading and motility, and remain important to establishing cellular responses required for foreign body reactions in vivo. Differences in Rho GTPase protein expression levels based on cell sourcing (primary versus secondary-derived cell source), or as a function of surface chemistry were insignificant. Rho GTPase expression profiles varied between pro-monocytic non-adherent precursor cells and mature adherent monocyte/macrophage cells. The active GTP-bound forms of the Rho GTPase proteins were detected from monocyte-macrophage cell lines RAW 264.7 and J774A.1 on all polymer surfaces, suggesting that while these proteins are central to cell adhesive behavior, differences in surface chemistry are insufficient to differentially regulate GTPase activation in these cell types. Active Cdc42 was detected from cells cultured on the more-polar tissue-culture polystyrene and poly-L-lactide surfaces after several days, but absent from those grown on apolar polystyrene and Teflon^® AF, indicating some surface influence on this GTPase in serum-containing cultures.     

Biomimetic Fabrication of Hydroxyapatite–Polysaccharide–Formate Dehydrogenase Composite Capsules for Efficient CO2 Conversion

In this study, a novel kind of hydroxyapatite–polysaccharide capsules was prepared through a bio-inspired process in simulated body fluid for efficient encapsulation of formate dehydrogenase. In this process, a thin alginate/chitosan film formed immediately around the capsules coupled with in situ precipitation of hydroxyapatite when alginate HPO₄ ^2?-stock solution droplets were added into chitosan Ca²⁺-stock solution. The biomineralization of hydroxyapatite was mimicked by the counter-diffusion system in which calcium ions and phosphate ions migrated into the alginate/chitosan film from opposite directions. Formation of capsule was confirmed by Zoom Stereo Microscopy, the surface morphology of the capsule was characterized by SEM, the surface element composition of capsules was analyzed by EDX and the pore size distribution of capsule shell was determined by BET. As compared to the free formate dehydrogenase, hydroxyapatite–polysaccharide–formate dehydrogenase composite capsules exhibited significantly higher activity and storage stability in a broader temperature and pH range when converting CO₂ to formic acid.     

Effect of an oral contraceptive containing drospirenone and ethinylestradiol on general well-being and fluid-related symptoms

Oral contraception is the most widely used reversible contraceptive method. Continuous research over the past decades has led to a range of highly reliable, effective and safe oral contraceptives. Newly developed progestogens may also provide additional non-contraceptive health-related benefits that differentiate the products from each other. Women desiring contraception may thus choose from a wide range of oral contraceptives according to their individual needs. A variety of physical and emotional changes have been linked to hormonal fluctuations during the menstrual cycle. To date, only very few studies have been performed on the impact of fluid retention-related symptoms on well-being and few data are hence available on suggested methods of measurement. This open, multicenter, uncontrolled study evaluated the effects of a combined preparation containing 3 mg drospirenone and 30 μg ethinylestradiol (Yasmin^®, Schering AG, Berlin, Germany) on general well-being and fluid-related symptoms in women experiencing psychological, behavioral and somatic premenstrual symptoms. The study was conducted over six 28-day cycles, with 336 subjects enrolled. A significant beneficial effect on psychological general well-being, as measured by the Psychological General Well-Being Index (PGWBI), was evident by cycle 3 and maintained at cycle 6. There was a significant reduction in both the incidence and severity of somatic symptoms associated with the menstrual cycle (abdominal bloating and breast tension) during treatment. Assessment by the investigator showed that 80% of subjects had improved on study treatment and 75% of subjects considered themselves satisfied with the study treatment. There was good agreement between the clinician and subject in their assessment of the treatment. Cycle control was very good and body weight remained stable or decreased slightly during the study. In conclusion, 3 mg drospirenone in combination with 30 μg ethinylestradiol has been shown to have a beneficial effect on psychological general well-being, as measured by the PGWBI. Reductions in the incidence and severity of somatic symptoms associated with the menstrual cycle were also observed, suggesting a beneficial effect due to the antimineralocorticoid nature of drospirenone. To our knowledge, this is the first study on oral contraceptives which has used the PGWBI in this population. As quality of life is one of the least explored segments in oral contraceptive users, more studies should investigate the impact of oral contraceptives on quality of life and general well-being in this overall healthy population.     

Effects of hyperprolactinemia on osteoporotic fracture in premenopausal women

The aim of the study was to evaluate the osteoporotic fracture risk in premenopausal women with hyperprolactinemia due to prolactinoma. Bone mineral density (BMD) was measured in 20 white ,premenopausal women with prolactinoma and in 60 healthy control white women ,using quantitative ultrasound (QUS) at the os calcis ,with an Achilles Lunar Plus device. We measured all three parameters of QUS: broadband ultrasound attenuation (BUA) ,speed of sound (SOS) and stiffness. BMD results were expressed also as T- and Z-scores. Age and body mass index (BMI) were not statistically significantly different between the two groups. Comparative analysis showed reduced values of QUS parameters in women with prolactinoma versus controls. Only the difference in SOS parameter was statistically significant between the two studied groups (p = 0.0001). The Z-score was significant lower in women with prolactinoma than in healthy women. These data reveal a significant bone loss in women with prolactinoma compared to controls.The SOS parameter showed a good negative correlation with age ,and all the QUS parameters were positively correlated with BMI. The relative risk for developing osteoporosis in women with prolactinoma was found to be 4.5 ,indicating that hyperprolactinemia in women is a major risk factor for osteoporosis.