At-home wireless monitoring of acute hemodynamic disturbances to detect sleep apnea and sleep stages via a soft sternal patch.

Obstructive sleep apnea (OSA) affects more than 900 million adults globally and can create serious health complications when untreated; however, 80% of cases remain undiagnosed. Critically, current diagnostic techniques are fundamentally limited by low throughputs and high failure rates. Here, we report a wireless, fully integrated, soft patch with skin-like mechanics optimized through analytical and computational studies to capture seismocardiograms, electrocardiograms, and photoplethysmograms from the sternum, allowing clinicians to investigate the cardiovascular response to OSA during home sleep tests.

Effects of Surface Topography and Chemistry on Polyether-Ether-Ketone (PEEK) and Titanium Osseointegration.

Study Design: An in vivo study examining the functional osseointegration of smooth, rough, and porous surface topographies presenting polyether-ether-ketone (PEEK) or titanium surface chemistry.

Objective: To investigate the effects of surface topography and surface chemistry on implant osseointegration.

Summary Of Background Data: Interbody fusion devices have been used for decades to facilitate fusion across the disc space, yet debate continues over their optimal surface topography and chemistry.

Effect of porous orthopaedic implant material and structure on load sharing with simulated bone ingrowth: A finite element analysis comparing titanium and PEEK.

Osseointegration of load-bearing orthopaedic implants, including interbody fusion devices, is critical to long-term biomechanical functionality. Mechanical loads are a key regulator of bone tissue remodeling and maintenance, and stress-shielding due to metal orthopaedic implants being much stiffer than bone has been implicated in clinical observations of long-term bone loss in tissue adjacent to implants. Porous features that accommodate bone ingrowth have improved implant fixation in the short term, but long-term retrieval studies have sometimes demonstrated limited, superficial ingrowth into the pore layer of metal implants and aseptic loosening remains a problem for a subset of patients.

Impaction durability of porous polyether-ether-ketone (PEEK) and titanium-coated PEEK interbody fusion devices.

Background Context: Various surface modifications, often incorporating roughened or porous surfaces, have recently been introduced to enhance osseointegration of interbody fusion devices. However, these topographical features can be vulnerable to damage during clinical impaction. Despite the potential negative impact of surface damage on clinical outcomes, current testing standards do not replicate clinically relevant impaction loading conditions.

Getting PEEK to Stick to Bone: The Development of Porous PEEK for Interbody Fusion Devices.

Interbody fusion cages are routinely implanted during spinal fusion procedures to facilitate arthrodesis of a degenerated or unstable vertebral segment. Current cages are most commonly made from polyether-ether-ketone (PEEK) due to its favorable mechanical properties and imaging characteristics. However, the smooth surface of current PEEK cages may limit implant osseointegration and may inhibit successful fusion.

Adipose stem cell microbeads as production sources for chondrogenic growth factors.

Microencapsulating stem cells in injectable microbeads can enhance delivery and localization, but their ability to act as growth factor production sources is still unknown. To address this concern, growth factor mRNA levels and production from alginate microbeads with encapsulated human adipose stem cells (ASC microbeads) cultured in both growth and chondrogenic media (GM and CM) were measured over a two week period. Human ASCs in microbeads were either commercially purchased (Lonza) or isolated from six human donors and compared to human ASCs on tissue culture polystyrene (TCPS).

High-strength, surface-porous polyether-ether-ketone for load-bearing orthopedic implants.

Despite its widespread clinical use in load-bearing orthopedic implants, polyether-ether-ketone (PEEK) is often associated with poor osseointegration. In this study, a surface-porous PEEK material (PEEK-SP) was created using a melt extrusion technique. The porous layer was 399.

Impaired bone formation in Pdia3 deficient mice.

1α,25-Dihydroxyvitamin D3 [1α,25(OH)2D3] is crucial for normal skeletal development and bone homeostasis. Protein disulfide isomerase family A, member 3 (PDIA3) mediates 1α,25(OH)2D3 initiated-rapid membrane signaling in several cell types. To understand its role in regulating skeletal development, we generated Pdia3-deficient mice and examined the physiologic consequence of Pdia3-disruption in embryos and Pdia3+/- heterozygotes at different ages.

Tailoring adipose stem cell trophic factor production with differentiation medium components to regenerate chondral defects.

Recent endeavors to use stem cells as trophic factor production sources have the potential to translate into viable therapies for damaged or diseased musculoskeletal tissues. Adipose stem cells (ASCs) can be differentiated into chondrocytes using the chondrogenic medium (CM), but it is unknown if this approach can optimize ASC growth factor secretion for cartilage regeneration by increasing the chondrogenic factor production, while decreasing angiogenic and hypertrophic factor production. The objective of this study was to determine the effects the CM and its components have on growth factor production from ASCs to promote cartilage regeneration.

Interrelationship of cranial suture fusion, basicranial development, and resynostosis following suturectomy in twist1(+/-) mice, a murine model of Saethre-Chotzen syndrome.

The interrelationships among suture fusion, basicranial development, and subsequent resynostosis in syndromic craniosynostosis have yet to be examined. The objectives of this study were to determine the potential relationship between suture fusion and cranial base development in a model of syndromic craniosynostosis and to assess the effects of the syndrome on resynostosis following suturectomy. To do this, posterior frontal and coronal suture fusion, postnatal development of sphenooccipital synchondrosis, and resynostosis in Twist1(+/+) (WT) and Twist1(+/-) litter-matched mice (a model for Saethre-Chotzen syndrome) were quantified by evaluating μCT images with advanced image-processing algorithms.

Coordinated tether formation in anatomically distinct mice growth centers is dependent on a functional vitamin D receptor and is tightly linked to three-dimensional tissue morphology.

Bone bridges linking the epiphysis and metaphysis termed "tethers" have been found in the femoral growth plates of C57Bl/6 mice and are disrupted when the vitamin D receptor (VDR) is ablated. It is unknown if tethers are found in other growth centers, if they are regulated in a comparable manner, or if they have a functional role in skeletal development or stability. To address this, distal femoral growth plates (GPs) and spheno-occipital synchondroses (SOSs) of wild-type C57Bl/6 mice from 2 to 15 weeks of age were analyzed using μCT scans.

Regulating in vivo calcification of alginate microbeads.

Alginate calcification has been previously reported clinically and during animal implantation; however no study has investigated the mechanism, extensively characterized the mineral, or evaluated multiple methods to regulate or eliminate mineralization. In the present study, alginate calcification was first studied in vitro: calcium-crosslinked alginate beads sequestered surrounding phosphate while forming traces of hydroxyapatite. Calcification in vivo was then examined in nude mice using alginate microbeads with and without adipose stem cells (ASCs).

The synergistic effects of 3-D porous silk fibroin matrix scaffold properties and hydrodynamic environment in cartilage tissue regeneration.

Autologous cell-based tissue engineering using three-dimensional porous scaffolds has provided a good option for the repair of cartilage defects. Silk fibroin-based scaffolds are naturally degradable materials with excellent biocompatibility and robust mechanical properties, indicating potential applications in cartilage tissue engineering. In this study, silk fibroin scaffolds prepared by freeze-drying (FD) and salt-leaching (SL300 and SL500) were fully characterized and used to study the effects of silk fibroin scaffold properties on chondrocyte attachment, proliferation and differentiation.

Diagnosis of bladder cancer with microelectromechanical systems-based cystoscopic optical coherence tomography.

Objectives: To examine the utility and potential limitations of microelectromechanical systems-based spectral-domain cystoscopic optical coherence tomography (COCT) so as to improve the diagnosis of early bladder cancer.

Methods: An optical coherence tomography catheter was integrated into the single instrument channel of a 22F cystoscope to permit white-light-guided COCT over a large field of view (4.6 mm wide and 2.

Formation of tethers linking the epiphysis and metaphysis is regulated by vitamin d receptor-mediated signaling.

Rat tibial growth plates have X-ray opaque tethers that link the epiphysis and metaphysis and increase with age as the growth plate (GP) becomes thinner. To determine if tether formation is a regulated process of GP maturation, we tested the hypotheses that tether properties and distribution can be quantified by micro-computed tomography (microCT), that rachitic GPs typical of vitamin D receptor knockout (VDR(-/-)) mice have fewer tethers and altered tether distribution, and that tether formation is regulated by signaling via the VDR. Distal femoral GPs from VDR(+/+) and VDR(-/-) 8-week-old mice were analyzed with microCT and then processed for decalcified and undecalcified histomorphometry.

The past, present and future of cystoscopy: the fusion of cystoscopy and novel imaging technology.

Non-muscle-invasive bladder cancer is a frequent disease with many recurrences, making it a labour-intensive and costly disease. In part, these frequent recurrences are due to inadequate diagnosis. Diagnostic reference standards to date are urinary cytology and cysto-urethroscopy, but both standards have significant limitations.

Adhesive properties of laminated alginate gels for tissue engineering of layered structures.

A significant challenge in tissue engineering is the creation of tissues with stratified morphology or embedded microstructures. This study investigated methods to fabricate composite gels from separately deposited alginate layers and examined the effects of processing methods on the mechanics of adhesion. Laminated alginate gels were created through a three step process which included: treatment of the interfaces with citrate; annealing of the gels to allow for molecular rearrangement of the alginate chains; and exposure to a CaCl(2) to crosslink the alginate sheets.

In vivo bladder imaging with microelectromechanical-systems-based endoscopic spectral domain optical coherence tomography.

We report the recent technical improvements in our microelectromechanical systems (MEMS)-based spectral-domain endoscopic OCT (SDEOCT) and applications for in vivo bladder imaging diagnosis. With the technical advances in MEMS mirror fabrication and endoscopic light coupling methods, the new SDEOCT system is able to visualize morphological details of the urinary bladder with high image fidelity close to bench-top OCT (e.g.

Integration of layered chondrocyte-seeded alginate hydrogel scaffolds.

Motivated by the necessity to engineer appropriately stratified cartilage, the shear mechanics of layered, bovine chondrocyte-seeded 20mg/mL alginate scaffolds were investigated and related to the structure and biochemical composition. Chondrocyte-seeded alginate scaffolds were exposed to a calcium-chelating solution, layered, crosslinked in CaCl(2), and cultured for 10 weeks. The shear mechanical properties of the layered gels were statistically similar to those of the non-layered controls.

A microfluidic biomaterial.

We report on the incorporation of microfluidic structure within a high-water-content hydrogel [4% (w/v) calcium alginate]. We used the microfluidic network to control the chemical environment within the hydrogel and demonstrated higher rates of delivery and extraction of solutes than was achievable by diffusion alone.

Highlights from the Society of Urologic Oncology 4th annual meeting.

Purpose: The 4th annual meeting of the Society of Urologic Oncology (SUO) was held December 5-6, 2003 in Bethesda, Maryland. The meeting was attended by urologists, medical and radiation oncologists, and researchers whose focus is genitourinary (GU) malignancies. More than 500 participants registered for the meeting.

Management of metastatic malignant melanoma of the bladder.

Recombinant interleukin-2 (IL-2) has demonstrated antitumor activity and durable clinical responses in patients with metastatic melanoma. Careful screening and selection of appropriate patients has improved the safety profile of IL-2 administration. Gross hematuria would ordinarily preclude the safe delivery of IL-2.

Insertion of interleukin-2 (IL-2) and interleukin-12 (IL-12) genes into vaccinia virus results in effective anti-tumor responses without toxicity.

Identification of novel tumor-associated antigens (TAA) capable of eliciting T-cell responses has renewed interest in the development of anti-tumor vaccines. The insertion of genes encoding specific TAA into a vaccinia virus (rVV) is one approach to vaccination since large amounts of foreign DNA can be stably integrated into the poxvirus genome. Recent reports have documented an increased therapeutic effectiveness of poxvirus-based vaccines when additional treatment with cytokines, such as interleukin-2 (IL-2) or interleukin-12 (IL-12) were used, but the combination of these cytokines as adjuvants for a rVV encoding TAA have not been previously reported.