Risk factors and prevalence of urinary incontinence in mid-life Singaporean women: the Integrated Women's Health Program.

INTRODUCTION AND HYPOTHESIS: The objective was to identify the prevalence and risk factors for urinary incontinence (UI) in healthy midlife Singaporean women. METHODS: Healthy women, aged 45-69 years, were assessed for UI and sociodemographic characteristics, including ethnicity, menopausal status, parity, and body mass index (BMI). UI subtypes corresponding to stress (SUI) alone, urge (UUI) alone, mixed (MUI), and leakage (drops only) incontinence were classified using the Urinary Distress Inventory 6 (UDI-6). Risk factors were examined using Chi-squared tests, followed by sequential multivariate logistic regression to estimate adjusted odds ratios (aOR and 95% confidence intervals). RESULTS: A total of 1,119 women (mean age 56.2 ± 5.2) completed the UDI-6. 52.3% reported any UI; MUI and SUI were the most common, each affecting 20% of women. Post-menopausal women had a lower risk (aOR 0.5 [0.3-0.9]) of SUI, but a higher risk (aOR 4.4 [1.0-19.9]) of UUI compared with premenopausal women. Higher education was negatively associated (aOR 0.3 [0.2-0.7]) with UUI, but positively associated with MUI (aOR 2.3 [1.3-4.0]). Parity (1-2 children) increased the risk of SUI (aOR 1.8 [1.0-3.1]), but reduced the risk of UUI (aOR 0.4 [0.2-0.9]). Obesity was associated with increased risk for MUI (aOR 2.2 [1.4-3.4]) and leakage (aOR 2.0 [1.0-4.1]). Malays and Indians had a higher risk of MUI, having (aOR 2.1 (1.2-3.7) and 1.7 (1.1-2.7) respectively compared with Chinese, a difference mediated by higher BMI. CONCLUSION: Urinary incontinence is a major morbidity prevalent in healthy midlife Asian women. Post-menopausal status, education level, parity, BMI (and its link with ethnicity) are independent risk factors in this population, and should be incorporated into counseling and targeted interventions.

Effects of Intranasal Oxytocin on the Interpretation and Expression of Emotions in Anorexia Nervosa.

Altered social-emotional functioning is considered to play an important role in the development and maintenance of anorexia nervosa (AN). Recently, there has been increasing interest in investigating the role of intranasal oxytocin in social-emotional processing. The present study aimed to investigate the effects of intranasal oxytocin on the interpretation and expression of emotions among people with AN. Thirty women with AN and 29 age-matched healthy women took part in the present study, which used a double-blind, placebo-controlled, cross-over design. The participants received a single dose of 40 IU of intranasal oxytocin in one session and a placebo spray in the other. Fifteen minutes after administration, the participants completed the Reading the Mind in the Eyes Test to assess the interpretation of complex emotions and mental states followed by a video task, which assessed expressions of facial affect when they were viewing humorous and sad film clips. The intranasal oxytocin did not significantly influence the expression or interpretation of emotions in the AN or healthy comparison groups. The AN group expressed significantly less positive emotion, spent more time looking away and reported experiencing a significantly more negative affect in response to the film clips. The finding that intranasal oxytocin had little to no effect on the interpretation or expression of emotions in either group supports the notion that the effects of oxytocin on social-emotional processing are not straightforward and may depend on individual and environmental differences, as well as the emotion being processed. Replication of these findings is necessary to explore the effect of timing on the effects of oxytocin before firm conclusions can be drawn. Nonetheless, these findings add to the steady accumulation of evidence that people with AN have reduced emotional expression and avoidance of emotionally provoking stimuli.

ß-Phase poly(vinylidene fluoride) films encouraged more homogeneous cell distribution and more significant deposition of fibronectin towards the cell-material interface compared to α-phase poly(vinylidene fluoride) films.

The piezoelectric response from ß-phase poly(vinylidene fluoride) (PVDF) can potentially be exploited for biomedical application. We hypothesized that α and ß-phase PVDF exert direct but different influence on cellular behavior. α- and ß-phase PVDF films were synthesized through solution casting and characterized with FT-IR, XRD, AFM and PFM to ensure successful fabrication of α and ß-phase PVDF films. Cellular evaluation with L929 mouse fibroblasts over one-week was conducted with AlamarBlue® metabolic assay and PicoGreen® proliferation assay. Immunostaining of fibronectin investigated the extent and distribution of extracellular matrix deposition. Image saliency analysis quantified differences in cellular distribution on the PVDF films. Our results showed that ß-phase PVDF films with the largest area expressing piezoelectric effect elicited highest cell metabolic activity at day 3 of culture. Increased fibronectin adsorption towards the cell-material interface was shown on ß-phase PVDF films. Image saliency analysis showed that fibroblasts on ß-phase PVDF films were more homogeneously distributed than on α-phase PVDF films. Taken collectively, the different molecular packing of α and ß-phase PVDF resulted in differing physical properties of films, which in turn induced differences in cellular behaviors. Further analysis of how α and ß-phase PVDF may evoke specific cellular behavior to suit particular application will be intriguing.

Parathyromatosis following spontaneous rupture of a parathyroid adenoma: natural history and the challenge of management.

Parathyromatosis, the presence of small nodules of hyper-functioning parathyroid tissue scattered throughout the soft tissues of the neck and superior mediastinum, is a rare cause of persistent primary hyperparathyroidism. We report the first case of parathyromatosis secondary to spontaneous rupture of a parathyroid adenoma. Despite running an indolent course, this case highlights the potential challenges of management of parathyromatosis and the value of calcimimetic therapy as an adjunct to surgery for disease control.

Titanium dioxide nanomaterials cause endothelial cell leakiness by disrupting the homophilic interaction of VE-cadherin.

The use of nanomaterials has raised safety concerns, as their small size facilitates accumulation in and interaction with biological tissues. Here we show that exposure of endothelial cells to TiO2 nanomaterials causes endothelial cell leakiness. This effect is caused by the physical interaction between TiO2 nanomaterials and endothelial cells' adherens junction protein VE-cadherin. As a result, VE-cadherin is phosphorylated at intracellular residues (Y658 and Y731), and the interaction between VE-cadherin and p120 as well as ß-catenin is lost. The resulting signalling cascade promotes actin remodelling, as well as internalization and degradation of VE-cadherin. We show that injections of TiO2 nanomaterials cause leakiness of subcutaneous blood vessels in mice and, in a melanoma-lung metastasis mouse model, increase the number of pulmonary metastases. Our findings uncover a novel non-receptor-mediated mechanism by which nanomaterials trigger intracellular signalling cascades via specific interaction with VE-cadherin, resulting in nanomaterial-induced endothelial cell leakiness.

Scanning tunneling microscope with two-dimensional translator.

Since the invention of the scanning tunneling microscope (STM), it has been a powerful tool for probing the electronic properties of materials. Typically STM designs capable of obtaining resolution on the atomic scale are limited to a small area which can be probed. We have built an STM capable of coarse motion in two dimensions, the z- and x-directions which are, respectively, parallel and perpendicular to the tip. This allows us to image samples with very high resolution at sites separated by macroscopic distances. This device is a single unit with a compact design making it very stable. It can operate in either a horizontal or vertical configuration and at cryogenic temperatures.

α- and ß-poly(vinylidene fluoride) evoke different cellular behaviours.

α-Phase poly(vinylidene fluoride) (PVDF) has chains of zero dipole moments and is, therefore, nonpiezoelectric, while ß-phase PVDF has the most significant piezoelectric properties among the polymorphs due to its polar chains. Although many reports describe PVDF as a suitable biomaterial due to its stability and biocompatibility, few considered the specific effects that the different polymorphs exert on cellular behaviour. We hypothesized that α- and ß-phase PVDF will exert direct but different influences on cell attachment and metabolic activity. PVDF films were fabricated using N,N-dimethylformamide (DMF) and hexamethylphosphoramide (HMPA) by solvent casting. Samples were characterized by differential scanning calorimetry, Fourier transform infrared spectroscopy and X-ray diffraction. Films containing 83.5% α-phase PVDF (DMF-PVDFα) and 91.4% of ß-phase PVDF (HMPA-PVDFß within the crystalline regions were produced and used to evaluate in vitro attachment and metabolic activity of L929 cells. Cell metabolic activity on both PVDF conformations increased 3-fold over the 1-week culture period, with higher cell metabolic activity observed on DMF-PVDFα on day 5 of culture, compared to HMPA-PVDFß. Cells grown on DMF-PVDFα were well-spread, flat and expressed spotted paxillin in focal adhesions that were mainly localized to perinuclear regions of the cells, while a high proportion of cells on HMPA-PVDFß were bulging, round and expressed relatively fewer paxillin spots. Our results suggest that α-phase PVDF supports higher cell metabolic activity and better cell spreading compared to ß-phase PVDF. Such variations can potentially be exploited for different biomedical applications.

Integration of CAD/CAM planning into computer assisted orthopaedic surgery.

Modern Computer Aided Design/Modeling (CAD/CAM) software allows complex surgical simulations, but it is often difficult to transfer and execute precisely the planned scenarios during actual operations. We describe a new method of integrating CAD/CAM surgical plans directly into a computer surgical navigation system, and demonstrate its use to guide three complex orthopaedic surgical procedures: a periacetabular osteotomy of a dysplastic hip, a corrective osteotomy of a post-traumatic tibial deformity, and a multi-planar resection of a distal femoral tumor followed by reconstruction with a CAD custom prosthesis.

DietPLUS- a User-friendly '2 in 1' Food Composition Database and Calculator of Nutrient Intakes.

The teaching and research tool called 'DietPLUS', developed by the present author at an institution of higher learning in 2007, contains nutrient information of 840 food items in Excel format. DietPLUS functions as a '2-in-1' food composition database plus a rapid calculator of nutrient intakes, with the option of 'collapsing' the food composition face leaving only the nutrient calculator face. The macronutrients featured in the programme are energy, protein, fat, carbohydrates, dietary fibre, sugars (intrinsic + added), polyunsatuared omega-6 fatty acids (mainly linoleic acid, LA) and polyunsaturated omega-3 fatty acids [alphalinolenic acid (ALA) or eicosapentaenic acid (EPA) + docosahexaenolic acid (DHA)]. The micronutrients in the programme are vitamin A (as retinol equivalents, RE), vitamin C, thiamin (vitamin B1), riboflavin (vitamin B2), and niacin. Cholesterol content was included to complete the list of food components tabled. Food items consumed are converted into gram quantities (edible portion) and are entered in one column in the Excel programme which emphasises the simplicity and user-friendliness of the present nutrient calculator. DietPLUS instantaneously sums up the macronutrients and micronutrients consumed with each subsequent entry. Macronutrients (protein, fat, carbohydrate, sugars and dietary fibre) consumed are presented as gram quantities and a percentage of the Recommended Nutrient Intakes for Malaysia 2005. An approximate number of servings are also provided for vegetables, fruits, legumes, fish and meat, which may be useful in meal planning and nutrition/dietetic counselling.

Future developments in osteoporosis therapy.

Anti-resorptives that prevent osteoclasts from resorbing bone are the mainstay of treatment for osteoporosis, while parathyroid hormone is the only agent available that stimulates osteoblasts to form bone. Advances in knowledge about metabolic pathways in bone cell biology have identified specific points of intervention whereby formation and function of osteoclasts and osteoblasts can be inhibited or stimulated. The next generation of therapies for osteoporosis may include molecules that antagonize integrin or inhibit Src tyrosine kinase, vacuolar H+-ATPase, chloride channel or cathepsin K, thus preventing osteoclasts from attaching to bone, form a ruffled border, acidify resorption lacunae or digest organic bone matrix. At least some of these may form a novel class of anti-resorptives capable of inhibiting bone resorption without being coupled to inhibition of bone formation. Human and mouse genetics studies demonstrating the pivotal role of the Wnt signaling pathway in bone metabolism have led to the development of strategies to disrupt Wnt signaling in order to increase bone formation. Selective androgen receptor modulators that produce an anabolic effect on muscle and bone without undesirable androgenic side effects can potentially be used to treat osteoporosis, aged-related frailty, muscle wasting disorders and glucocorticoid-induced osteoporosis. Studies involving these molecules are still in either preclinical or early investigational stage, without fracture data. Nonetheless, preliminary results hold the promise that at least some of these new therapies may develop into effective means of treating and preventing osteoporosis. Any new therapy for osteoporosis must take into consideration its safety, efficacy, affordability and specificity of action.

Stockholm Convention organochlorine pesticides and polycyclic aromatic hydrocarbons in Hong Kong air.

Organochlorine pesticides (OCPs) including eight of the original nine pesticides listed in the Stockholm Convention on Persistent Organic Pollutants, and polycyclic aromatic hydrocarbons (PAHs) were measured in 90 air samples collected from January 2004 to March 2005, and in 304 air samples collected from January 1998 to December 2005 in Hong Kong, respectively. The annual average OCP concentrations at Tap Mun, Yuen Long and Tsuen Wan were 135+/-140 (ND-482), 186+/-183 (ND-656), and 190+/-239 fg m(-3) (ND-966), respectively, while annual (January 1998 to December 2005) average concentrations of total PAHs at Tsuen Wan, and Central/Western were 578+/-261 (117-938) and 588+/-248ngm(-3) (103-874), respectively. No seasonal and spatial variations in OCP concentrations were observed due to trace levels, and estimation of carcinogenic risks of OC pesticides was low. Naphthalene (>70%) was the dominant PAH in terms of concentrations measured. The sum of three-ring PAHs, including acenaphthene, acenaphthylene, anthracene, fluorene and phenanthrene, contributed to around 20% of the total PAH concentration while the contribution of heavier PAHs (sum of four-, five- and six-rings) was less than 5%. t-Values of the paired samples T-test for the individual PAHs showed that the concentrations of benzo(a)pyrene, the relative high cancer risk PAH, and most of the PAHs detected at Tsuen Wan and Central/Western were significantly different (p<0.01), with higher concentrations detected at Tsuen Wan. Several PAHs exhibited strong seasonality with higher concentrations in winter. Sources of PAHs were determined by investigating PAH isomer ratios which suggested petrogenic sources as primary sources of PAHs in Hong Kong air.

Clinical features and epidemiology of chikungunya infection in Singapore.

Chikungunya is a re-emerging mosquito-borne viral infection that has spread from East Africa to Indian Ocean islands and re-emerged in India since 2004. In Malaysia, chikungunya re-emerged after a hiatus of seven years, causing a localised outbreak in a north-western coastal town in 2006 and subsequently widespread outbreaks in 2008. Since the first local outbreak of chikungunya in Singapore in January 2008, chikungunya infections have been increasingly reported in Singapore. In this case series, five patients aged 37-62 years, with chikungunya infection confirmed in August 2008, were reported. Three of the five were male, and only one had medical comorbidities. Two had a travel history to Johor, Malaysia, where local outbreaks of chikungunya had been reported. Fever, arthralgia and rash were the most common symptoms. Fever lasted four to five days while viraemia lasted four to 11 days, persisting two to three days after defervescence in three patients. A biphasic pattern of fever was observed in two patients. Leucopenia was noted in all patients, while mild thrombocytopenia and transaminitis occurred in three of five patients. Two patients had persistent polyarthralgia at two to three weeks after the onset of symptoms. Fever, arthralgia and rash should prompt consideration of acute chikungunya in Singapore. While taking the travel history, doctors should be mindful that indigenous chikungunya cases can occur.

Analysis of radial variations in material properties and matrix composition of chondrocyte-seeded agarose hydrogel constructs.

OBJECTIVE: To examine the radial variations in engineered cartilage that may result due to radial fluid flow during dynamic compressive loading. This was done by evaluating the annuli and the central cores of the constructs separately. METHOD: Chondrocyte-seeded agarose hydrogels were grown in free-swelling and dynamic, unconfined loading cultures for 42 days. After mechanical testing, constructs were allowed to recover for 1-2h, the central 3mm cores removed, and the cores and annuli were retested separately. Histological and/or biochemical analyses for DNA, glycosaminoglycan (GAG), collagen, type I collagen, type II collagen, and elastin were performed. Multiple regression analysis was used to determine the correlation between the biochemical and material properties of the constructs. RESULTS: The cores and annuli of chondrocyte-seeded constructs did not exhibit significant differences in material properties and GAG content. Annuli possessed greater DNA and collagen content over time in culture than cores. Dynamic loading enhanced the material properties and GAG content of cores, annuli, and whole constructs relative to free-swelling controls, but it did not alter the radial variations compared to free-swelling culture. CONCLUSION: Surprisingly, the benefits of dynamic loading on tissue properties extended through the entire construct and did not result in radial variations as measured via the coring technique in this study. Nutrient transport limitations and the formation of a fibrous capsule on the periphery may explain the differences in DNA and collagen between cores and annuli. No differences in GAG distribution may be due to sufficient chemical signals and building blocks for GAG synthesis throughout the constructs.

Influence of decreasing nutrient path length on the development of engineered cartilage.

OBJECTIVE: Chondrocyte-seeded agarose constructs of 4mm diameter (2.34 mm thickness) develop spatially inhomogeneous material properties with stiffer outer edges and a softer central core suggesting nutrient diffusion limitations to the central construct region [Guilak F, Sah RL, Setton LA. Physical regulation of cartilage metabolism. In: Mow VC, Hayes WC, Eds. Basic Orthopaedic Biomechanics, Philadelphia 1997;179-207.]. The effects of reducing construct thickness and creating channels running through the depth of the thick constructs were examined. METHODS: In Study 1, the properties of engineered cartilage of 0.78 mm (thin) or 2.34 mm (thick) thickness were compared. In Study 2, a single nutrient channel (1 mm diameter) was created in the middle of each thick construct. In Study 3, the effects of channels on larger 10 mm diameter, thick constructs were examined. RESULTS: Thin constructs developed superior mechanical and biochemical properties than thick constructs. The channeled constructs developed significantly higher mechanical properties vs control channel-free constructs while exhibiting similar glycosaminoglycan (GAG) and collagen content. Collagen staining suggested that channels resulted in a more uniform fibrillar network. Improvements in constructs of 10 mm diameter were similarly observed. CONCLUSIONS: This study demonstrated that more homogeneous tissue-engineered cartilage constructs with improved mechanical properties can be achieved by reducing their thickness or incorporating macroscopic nutrient channels. Our data further suggests that these macroscopic channels remain open long enough to promote this enhanced tissue development while exhibiting the potential to refill with cell elaborated matrix with additional culture time. Together with reports that <3 mm defects in cartilage heal in vivo and that irregular holes are associated with clinically used osteochondral graft procedures, we anticipate that a strategy of incorporating macroscopic channels may aid the development of clinically relevant engineered cartilage with functional properties.

Scaffold degradation elevates the collagen content and dynamic compressive modulus in engineered articular cartilage.

OBJECTIVE: It was hypothesized that controlled, scaffold removal in engineered cartilage constructs would improve their collagen content and mechanical properties over time in culture. DESIGN: Preliminary experiments characterized the effects of agarase on cell-free agarose disks and cartilage explants. Immature bovine chondrocytes were encapsulated in agarose, cultured to day 42, and incubated with 100 units/mL agarase for 48 h. After treatment, constructs were cultured to day 91. The compressive Young's modulus and dynamic modulus of the constructs were determined every 2 weeks and immediately after agarase treatment. Post-mechanical testing, constructs were processed for biochemistry and histology. RESULTS: Agarase treatment on explants had no detrimental effect on the cartilage matrix. Treatment applied to engineered constructs on day 42 did not affect DNA or collagen content. Agarase treatment decreased tissue GAG content (via GAG loss to the media) and Young's modulus, both of which recovered to control values over time in culture. By day 91 agarase-treated constructs possessed approximately 25% more DNA, approximately 60% more collagen, and approximately 40% higher dynamic modulus compared to untreated controls. CONCLUSIONS: Scaffold degradation increased construct collagen content and dynamic mechanical properties, affirming the experimental hypothesis. The mechanism may lie in increased nutrient transport, increased space for collagen fibril formation, and cellular response to the loss of GAG with agarase treatment. The results highlight the role of the scaffold in retaining synthesized matrix during early and late tissue formation. This work also shows promise in developing an engineered tissue that may be completely free of scaffold material for clinical implantation.

Mechanical and biochemical characterization of cartilage explants in serum-free culture.

Allografts of articular cartilage are both used clinically for tissue-transplantation procedures and experimentally as model systems to study the physiological behavior of chondrocytes in their native extracellular matrix. Long-term maintenance of allograft tissue is challenging. Chemical mediators in poorly defined culture media can stimulate cells to quickly degrade their surrounding extracellular matrix. This is particularly true of juvenile cartilage which is generally more responsive to chemical stimuli than mature tissue. By carefully modulating the culture media, however, it may be possible to preserve allograft tissue over the long-term while maintaining its original mechanical and biochemical properties. In this study juvenile bovine cartilage explants (both chondral and osteochondral) were cultured in both chemically defined medium and serum-supplemented medium for up to 6 weeks. The mechanical properties and biochemical content of explants cultured in chemically defined medium were enhanced after 2 weeks in culture and thereafter remained stable with no loss of cell viability. In contrast, the mechanical properties of explants in serum-supplemented medium were degraded by ( approximately 70%) along with a concurrent loss of biochemical content (30-40% GAG). These results suggest that long-term maintenance of allografts can be extended significantly by the use of a chemically defined medium.

Regulatory pathways revealing new approaches to the development of anabolic drugs for osteoporosis.

The understanding of cell interactions and genetic controls of bone cells has provided new approaches to drug development for osteoporosis. Current emphasis in the development of new anabolic therapies is directed at modifying the effects of Wnt signalling on osteoblast differentiation and bone formation. Local signalling that results in bone formation during remodelling takes place in several ways. Growth factors released from resorbed bone matrix can contribute to preosteoblast differentiation and bone formation. Osteoclasts in the bone multicellular units (BMUs) might also generate activity that contributes to bone formation. The preosteoblasts themselves, growing in the resorption space, can communicate through cell contact and paracrine signalling mechanisms to differentiate. Osteocytes can sense the need for bone repair by detecting damage and pressure changes, and signalling to surface cells to respond appropriately. These recent insights into cell communication, together with discoveries from human and mouse genetics, have opened new pathways to drug development for osteoporosis. With the anabolic effect of parathyroid hormone on the skeleton having been established, human genetics revealed the major role of Wnt signalling in bone formation, and this has become the target of activity. Current approaches include activation at any of several points in the Wnt pathway, and neutralization of sclerostin, the protein product of the SOST gene that is produced in osteocytes as a powerful inhibitor of bone formation.

Amino acids supply in culture media is not a limiting factor in the matrix synthesis of engineered cartilage tissue.

Increased amino acid supplementation (0.5 x, 1.0 x, and 5.0 x recommended concentrations or additional proline) was hypothesized to increase the collagen content in engineered cartilage. No significant differences were found between groups in matrix content or dynamic modulus. Control constructs possessed the highest compressive Young's modulus on day 42. On day 42, compared to controls, decreased type II collagen was found with 0.5 x, 1.0 x, and 5.0 x supplementation and significantly increased DNA content found in 1.0 x and 5.0 x. No effects were observed on these measures with added proline. These results lead us to reject our hypothesis and indicate that the low collagen synthesis in engineered cartilage is not due to a limited supply of amino acids in media but may require a further stimulatory signal. The results of this study also highlight the impact that culture environment can play on the development of engineered cartilage.