Active osseointegration in an ex vivo porcine bone model

Achieving osseointegration is a fundamental requirement for many orthopaedic, oral, and craniofacial implants. Osseointegration typically takes three to 6 months, during which time implants are at risk of loosening. The aim of this study was to investigate whether osseointegration could be actively enhanced by delivering controllable electromechanical stimuli to the periprosthetic bone. First, the osteoconductivity of the implant surface was confirmed using an in vitro culture with murine preosteoblasts. The effects of active treatment on osseointegration were then investigated in a 21-day ex vivo model with freshly harvested cancellous bone cylinders (n = 24; Ø10 mm × 5 mm) from distal porcine femora, with comparisons to specimens treated by a distant ultrasound source and static controls. Cell viability, proliferation and distribution was evident throughout culture. Superior ongrowth of tissue onto the titanium discs during culture was observed in the actively stimulated specimens, with evidence of ten-times increased mineralisation after 7 and 14 days of culture (p < 0.05) and 2.5 times increased expression of osteopontin (p < 0.005), an adhesive protein, at 21 days. Moreover, histological analyses revealed increased bone remodelling at the implant-bone interface in the actively stimulated specimens compared to the passive controls. Active osseointegration is an exciting new approach for accelerating bone growth into and around implants.

Electromechanical and biological evaluations of 0.94Bi0.5Na0.5TiO3-0.06BaTiO3 as a lead-free piezoceramic for implantable bioelectronics

Smart implantable electronic medical devices are being developed to deliver healthcare that is more connected, personalised, and precise. Many of these implantables rely on piezoceramics for sensing, communication, energy autonomy, and biological stimulation, but the piezoceramics with the strongest piezoelectric coefficients are almost exclusively lead-based. In this article, we evaluate the electromechanical and biological characteristics of a lead-free alternative, 0.94Bi0.5Na0.5TiO3-0.06BaTiO3 (BNT-6BT), manufactured via two synthesis routes: the conventional solid-state method (PIC700) and tape casting (TC-BNT-6BT). The BNT-6BT materials exhibited soft piezoelectric properties, with d33 piezoelectric coefficients that were inferior to commonly used PZT (PIC700: 116 pC/N; TC-BNT-6BT: 121 pC/N; PZT-5A: 400 pC/N). The material may be viable as a lead-free substitute for soft PZT where moderate performance losses up to 10 dB are tolerable, such as pressure sensing and pulse-echo measurement. No short-term harmful biological effects of BNT-6BT were detected and the material was conducive to the proliferation of MC3T3-E1 murine preosteoblasts. BNT-6BT could therefore be a viable material for electroactive implants and implantable electronics without the need for hermetic sealing.

Parents of preschoolers use multiple strategies to feed their children: Findings from an observational video pilot study

The current study leveraged observational data collection methods to fill gaps in our understanding of parent approach to feeding as well as child responses to various parental approaches. Specifically, the study aimed to: 1) characterize the broad range of food parenting practices used by parents of preschoolers during shared mealtimes at home, including differences by child gender, and 2) describe child responses to specific parent feeding practices. Forty parent-child dyads participated by recording two in-home shared meals. Meals were coded using a behavioral coding scheme that coded the occurrence of 11 distinct food parenting practices (e.g. indirect and direct commands, praise, bribes) and eight child responses (e.g., eat, refuse, cry/whine) to food parenting practices. Results revealed that parents engaged in a broad range of food parenting practices at meals. On average, parents in our sample used 10.51 (SD 7.83; Range 0-30) total food parenting practices per mealtime with a mean use of 3.38 (SD 1.67; Range 0-8) unique food parenting practices per mealtime. Use of indirect and direct commands to eat were most common; direct and indirect commands were used by 97.5% (n = 39) and 87.5% (n = 35) of parents at meals, respectively. No statistically significant differences were observed by child gender. No one specific feeding practice consistently yielded compliance or refusal to eat from the child, instead child responses were often mixed (e.g., compliance followed by refusal and/or refusal followed by compliance). However, use of praise to prompt eating was the practice that most often resulted in child compliance; 80.8% of children complied following parent's use of praise as a prompt to eat. Findings deepen our understanding of the types and frequency of food parenting practices used by parents of preschoolers during meals eaten at home and illuminate child responses to specific food parenting practices.

Bioreactor analyses of tissue ingrowth, ongrowth and remodelling around implants: An alternative to live animal testing

Introduction: Preclinical assessment of bone remodelling onto, into or around novel implant technologies is underpinned by a large live animal testing burden. The aim of this study was to explore whether a lab-based bioreactor model could provide similar insight. Method: Twelve ex vivo trabecular bone cylinders were extracted from porcine femora and were implanted with additively manufactured stochastic porous titanium implants. Half were cultured dynamically, in a bioreactor with continuous fluid flow and daily cyclic loading, and half in static well plates. Tissue ongrowth, ingrowth and remodelling around the implants were evaluated with imaging and mechanical testing. Results: For both culture conditions, scanning electron microscopy (SEM) revealed bone ongrowth; widefield, backscatter SEM, micro computed tomography scanning, and histology revealed mineralisation inside the implant pores; and histology revealed woven bone formation and bone resorption around the implant. The imaging evidence of this tissue ongrowth, ingrowth and remodelling around the implant was greater for the dynamically cultured samples, and the mechanical testing revealed that the dynamically cultured samples had approximately three times greater push-through fixation strength (p < 0.05). Discussion: Ex vivo bone models enable the analysis of tissue remodelling onto, into and around porous implants in the lab. While static culture conditions exhibited some characteristics of bony adaptation to implantation, simulating physiological conditions with a bioreactor led to an accelerated response.

Poly-ε-Caprolactone/Fibrin-Alginate Scaffold: A New Pro-Angiogenic Composite Biomaterial for the Treatment of Bone Defects

We hypothesized that a composite of 3D porous melt-electrowritten poly-ɛ-caprolactone (PCL) coated throughout with a porous and slowly biodegradable fibrin/alginate (FA) matrix would accelerate bone repair due to its angiogenic potential. Scanning electron microscopy showed that the open pore structure of the FA matrix was maintained in the PCL/FA composites. Fourier transform infrared spectroscopy and differential scanning calorimetry showed complete coverage of the PCL fibres by FA, and the PCL/FA crystallinity was decreased compared with PCL. In vitro cell work with osteoprogenitor cells showed that they preferentially bound to the FA component and proliferated on all scaffolds over 28 days. A chorioallantoic membrane assay showed more blood vessel infiltration into FA and PCL/FA compared with PCL, and a significantly higher number of bifurcation points for PCL/FA compared with both FA and PCL. Implantation into a rat cranial defect model followed by microcomputed tomography, histology, and immunohistochemistry after 4- and 12-weeks post operation showed fast early bone formation at week 4, with significantly higher bone formation for FA and PCL/FA compared with PCL. However, this phenomenon was not extrapolated to week 12. Therefore, for long-term bone regeneration, tuning of FA degradation to ensure syncing with new bone formation is likely necessary.

Pro-angiogenic and osteogenic composite scaffolds of fibrin, alginate and calcium phosphate for bone tissue engineering

Due to the limitations of bone autografts, we aimed to develop new composite biomaterials with pro-angiogenic and osteogenic properties to be used as scaffolds in bone tissue engineering applications. We used a porous, cross-linked and slowly biodegradable fibrin/alginate scaffold originally developed in our laboratory for wound healing, throughout which deposits of calcium phosphate (CaP) were evenly incorporated using an established biomimetic method. Material characterisation revealed the porous nature and confirmed the deposition of CaP precursor phases throughout the scaffolds. MC3T3-E1 cells adhered to the scaffolds, proliferated, migrated and differentiated down the osteogenic pathway during the culture period. Chick chorioallantoic membrane (CAM) assay results showed that the scaffolds were pro-angiogenic and biocompatible. The work presented here gave useful insights into the potential of these pro-angiogenic and osteogenic scaffolds for bone tissue engineering and merits further research in a pre-clinical model prior to its clinical translation.

Towards the Development of a Novel Ex Ovo Model of Infection to Pre-Screen Biomaterials Intended for Treating Chronic Wounds

This communication reports preliminary data towards the development of a live ex vivo model of persistent infection that is based on the chick embryo chorioallantoic membrane (CAM), which can be used for pre-screening biomaterials with antimicrobial properties for their antimicrobial and angiogenic potential. Our results showed that it was possible to infect chicken embryos with Staphylococcus aureus, one of the main types of bacteria found in the persistent infection associated with chronic wounds, and maintain the embryos’ survival for up to 48 h. Survival of the embryos varied with the dose of bacteria inoculum and with the use and time of streptomycin application after infection. In infected yet viable embryos, the blood vessels network of the CAM was maintained with minimal disruption. Microbiological tests could confirm embryo infection, but quantification was difficult. By publishing these preliminary results, we hope that not only our group but others within the scientific community further this research towards the establishment of biomimetic and reproducible ex vivo models of persistent infection.

0820 Meta-Analysis of the Association of Age and Actigraphy-Assessed Sleep Across the Lifespan

Introduction

Sleep quantity and continuity vary across the lifespan. Actigraphy is reliable, ecologically valid, and is the most widely-used behavioral measure of sleep in research and personal health monitoring. The extent to which age is associated with actigraphy-assessed sleep has not been evaluated across the lifespan. The aim of this meta-analysis was to evaluate the associations between age and actigraphy-assessed sleep in relatively healthy individuals.

Methods

A systematic search of PubMed, Embase.com, Cochrane CENTRAL, and PsycINFO using “actigraphy” and “sleep” terms provided 7,079 titles/abstracts, which were screened to exclude studies of only individuals with mental health disorders, medical conditions, sleep disorders, or shift workers. We evaluated 1,379 full-text articles for reports on the association between age and actigraphy-assessed sleep duration, efficiency, timing, and/or regularity. Overall, 88 articles met these criteria (182 effect sizes; N=18,443). Four meta-analyses were conducted, examining sleep duration (k=86), sleep efficiency (k=58), bedtime (k=27), and wake-up time (k=11). There were insufficient numbers of studies (less than 5) to evaluate sleep midpoint or sleep regularity. We tested continent of the study, study design, actigraphy device type, and number of nights of data collection as moderators of meta-analytic associations.

Results

With increasing age, sleep duration was shorter (r = -0.13) and sleep efficiency was lower (r = -0.06). Bedtime was later with age for ages 6-21 (r = 0.31) and earlier for ages 22 and up (r = -0.65). Wake-up time was not associated with age for ages 6-21 (r = 0.20) but was earlier with increasing age for ages 22 and up (r = -0.71). The strength of these associations was modified by continent and study design, but not by type of actigraphy device or number of nights of data collection.

Conclusion

Weak associations between age and actigraphy-assessed duration and efficiency suggest that inadequate sleep quantity or poor sleep continuity should not be dismissed as typical consequences of aging. Large associations between age and sleep timing, despite a small literature, highlights a promising area for further study, particularly to determine the age at which sleep timing shifts from delaying to advancing.

Support

MAB was supported by T32 HL07560.

A Synergistic Relationship between Polycaprolactone and Natural Polymers Enhances the Physical Properties and Biological Activity of Scaffolds

Biomaterials for tissue engineering include natural and synthetic polymers, but their clinical application is still limited due to various disadvantages associated with the use of these polymers. This uncertainty of the polymeric approach in tissue engineering launches an opportunity to address a key question: can we eliminate the disadvantages of both natural and synthetic polymers by combining them to form a synergistic relationship? To answer this question, we fabricated scaffolds from elastin, collagen, fibrin, and electrospun polycaprolactone (PCL) with different ratios. The material characterization of these scaffolds investigated degradation, water contact angle, angiogenesis by an ex ovo chorion allantoic membrane (CAM) assay, and mechanical and structural properties. Biological activity and specific differentiation pathways (MSC, adipogenic, osteogenic, myogenic, and chondrogenic) were studied by using human adipose-derived stem cells. Results indicated that all composite polymers degraded at a different rate, thus affecting their mechanical integrity. Cell-based assays demonstrated continual proliferative and viable properties of the cells on all seeded scaffolds with the particular initiation of a differentiation pathway among which the PCL/collagen/fibrin composite was the most angiogenic material with maximum vasculature. We were able to tailor the physical and biological properties of PCL-based composites to form a synergistic relationship for various tissue regeneration applications.

Pre-screening the intrinsic angiogenic capacity of biomaterials in an optimised ex ovo chorioallantoic membrane model

Biomaterial development for clinical applications is currently on the rise. This necessitates adequate in vitro testing, where the structure and composition of biomaterials must be specifically tailored to withstand in situ repair and regeneration responses for a successful clinical outcome. The chorioallantoic membrane of chicken embryos has been previously used to study angiogenesis, a prerequisite for most tissue repair and regeneration. In this study, we report an optimised ex ovo method using a glass-cling film set-up that yields increased embryo survival rates and has an improved protocol for harvesting biomaterials. Furthermore, we used this method to examine the intrinsic angiogenic capacity of a variety of biomaterials categorised as natural, synthetic, natural/synthetic and natural/natural composites with varying porosities. We detected significant differences in biomaterials' angiogenesis with natural polymers and polymers with a high overall porosity showing a greater vascularisation compared to synthetic polymers. Therefore, our proposed ex ovo chorioallantoic membrane method can be effectively used to pre-screen biomaterials intended for clinical application.

Biomimetic In Vitro Model of Cell Infiltration into Skin Scaffolds for Pre-Screening and Testing of Biomaterial-Based Therapies

Due to great clinical need, research where different biomaterials are tested as 3D scaffolds for skin tissue engineering has increased. In vitro studies use a cell suspension that is simply pipetted onto the material and cultured until the cells migrate and proliferate within the 3D scaffold, which does not mimic the in vivo reality. Our aim was to engineer a novel biomimetic in vitro model that mimics the natural cell infiltration process occurring in wound healing, thus offering a realistic approach when pre-screening and testing new skin substitutes. Our model consists of porous membrane cell culture inserts coated with gelatin and seeded with human dermal fibroblasts, inside which two different commercially available dermal substitutes were placed. Several features relevant to the wound healing process (matrix contraction, cell infiltration and proliferation, integration of the biomaterial with the surrounding tissue, and secretion of exogenous cytokines and growth factors) were evaluated. Our results showed that cells spontaneously infiltrate the materials and that our engineered model is able to induce and detect subtle differences between different biomaterials. The model allows for room for improvements or "adds-on" and miniaturization and can contribute to the development of functional and efficient skin substitutes for burns and chronic wounds.

Bone remodelling in vitro: Where are we headed?: -A review on the current understanding of physiological bone remodelling and inflammation and the strategies for testing biomaterials in vitro

Bone remodelling is a dynamic process required for the maintenance of bone architecture in response to the changing mechanical needs. It is also a vital process during the repair of bone tissue following injury. Clinical intervention in terms of autografting or allografting is often required to heal bone injuries where physiological healing fails. The use of biomaterials as alternatives to autografts and allografts has spurred a significant research interest into further development of biomaterials for better clinical outcomes. Unfortunately, many biomaterials fail to make it to the clinic or fail after implantation due to the inconsistencies observed between in vitro and in vivo studies. It is therefore important to mimic the in vivo situation as closely as possible in an in vitro setting for testing biomaterials. The current in vitro models focus mostly on investigating the behaviour of osteoblast progenitors with the biomaterial under development as well as assessing the behaviour of osteoclasts, endothelial cells etc. However, the sequence of events that take place during bone healing or remodelling are not incorporated into the current in vitro models. This review highlights our current understanding of the physiological bone remodelling and the bone healing process followed by strategies to incorporate both the physiological and pathophysiological events into an in vitro environment. Here, we propose three strategies for the assessment of biomaterials for bone, which includes; (1) testing biomaterials in the presence of immune cells, (2) testing biomaterials for osteogenesis, and (3) testing biomaterials in the presence of osteoclasts followed by osteoblasts to recapitulate the physiological events of bone resorption prior to bone formation. The focus of this review is to discuss the third strategy in details as the first two strategies are currently incorporated into a majority of in vitro experiments.

Preliminary clinical assessment and non- toxicity evaluation of an ayurvedic formulation BGR-34 in NIDDM

In view of the overall health impact of NIDDM, inventers understand the necessity of improving glycemic control in adults with type 2 diabetes. BGR-34 provides an effective treatment option for adults with type 2 diabetes who have been inadequately controlled on lifestyle with or without other oral hypoglycemic agents (OHGAs) such as metformin, sulfonylurea, or a glitazones. BGR-34 is an appropriate option to consider for addition to a managed care drug formulary. Treatment with BGR-34 produced clinically relevant and statistically significant reductions in all three key measures of glucose control studied -FPG, PPBG and HbA1c- when compared with placebo. BGR-34, showed the promising result with respect to glycemic parameters in NIDDM patient with a significant reduction in fasting blood sugar by 34.3%, postprandial blood sugar 35.5% & glycosylated haemoglobin by 20.31% as compared to placebo group showing a reduction by 13.2%, 10.9% & 10.87% respectively. The trial has also been registered to CTRI, India. This study has been registered in the clinical trial registry-India.

Evaluation of an assessment instrument for a sexual health curriculum for nurses and midwifery students in Tanzania: The sexual health education for professionals scale (SHEPS)

We assessed the structure and content of a new scale, the SHEPS, to assess change in sexual health confidence, knowledge and attitudes in nursing and midwifery students following an intervention (a 2-day standardized workshop on sexual health). Students were 78 Tanzanian nursing and midwifery students attending a University of Health Sciences, who were assessed immediately before and after the workshop on matched pre- and post-workshop questionnaires. Data confirmed significant changed pre- and post-test on knowledge and confidence on topics taught in the workshop, with the effect also extending to some topics not or minimally covered, suggesting that there was a general increase in confidence and a perception of increased knowledge following the workshop. There was power to detect differences even with a moderate sized matched sample. Correlations between knowledge and confidence on the same content items were between 0.52 and 0.63, suggesting that respondents could clearly distinguish between knowledge and confidence. There were no significant differences pre- and post-test on several controversial cultural and religious attitudes including on abortion and non-vaginal penetrative sex. Alpha coefficients were 0.93 for pre-test and 0.90 for post-test. This field test demonstrates the preliminary appropriateness of the SHEPS as a tool for evaluating sexual health interventions in health care workers.

Predictive Models in Differentiating Vertebral Lesions Using Multiparametric MRI

BACKGROUND AND PURPOSE

Conventional MR imaging has high sensitivity but limited specificity in differentiating various vertebral lesions. We aimed to assess the ability of multiparametric MR imaging in differentiating spinal vertebral lesions and to develop statistical models for predicting the probability of malignant vertebral lesions.

MATERIALS AND METHODS

One hundred twenty-six consecutive patients underwent multiparametric MRI (conventional MR imaging, diffusion-weighted MR imaging, and in-phase/opposed-phase imaging) for vertebral lesions. Vertebral lesions were divided into 3 subgroups: infectious, noninfectious benign, and malignant. The cutoffs for apparent diffusion coefficient (expressed as 10^-3 mm²/s) and signal intensity ratio values were calculated, and 3 predictive models were established for differentiating these subgroups.

RESULTS

Of the lesions of the 126 patients, 62 were infectious, 22 were noninfectious benign, and 42 were malignant. The mean ADC was 1.23 ± 0.16 for infectious, 1.41 ± 0.31 for noninfectious benign, and 1.01 ± 0.22 mm²/s for malignant lesions. The mean signal intensity ratio was 0.80 ± 0.13 for infectious, 0.75 ± 0.19 for noninfectious benign, and 0.98 ± 0.11 for the malignant group. The combination of ADC and signal intensity ratio showed strong discriminatory ability to differentiate lesion type. We found an area under the curve of 0.92 for the predictive model in differentiating infectious from malignant lesions and an area under the curve of 0.91 for the predictive model in differentiating noninfectious benign from malignant lesions. On the basis of the mean ADC and signal intensity ratio, we established automated statistical models that would be helpful in differentiating vertebral lesions.

CONCLUSIONS

Our study shows that multiparametric MRI differentiates various vertebral lesions, and we established prediction models for the same.

Biomimetic surface functionalization of clinically relevant metals used as orthopaedic and dental implants

Titanium and its alloys or tantalum (Ta) are materials used in orthopaedic and dental implants due to their excellent mechanical properties and biocompatibility. However, their bioactivity and osteoconductivity is low. With a view to improving the bioactivity of these materials we hypothesised that the surface of Ta and TiAl6V4 can be functionalised with biomimetic, amorphous nano-sized calcium phosphate (CaP) apatite-like deposits, instead of creating uniform coatings, which can lead to flaking, delamination and poor adherence. We used Ta and TiAl6V4 metal discs with smooth and rough surfaces. Amorphous CaP apatite-like particles were deposited on the different surfaces by a biomimetic rapid two-step soaking method using concentrated simulated body fluid (SBF) solutions without a pre-treatment of the metal surfaces to induce CaP deposition. Immersion times in the second SBF solution of 48 and 18 h for Ta and TiAl6V4 respectively produced CaP deposits composed of amorphous globular nano-sized particles that also contained Mg, C and O. Longer immersion times produced more uniform coatings as well as an undesired calcite mineral phase. Prediction of in vivo behaviour by immersion in regular SBF showed that the obtained CaP deposits would act as a catalyst to rapidly form a Ca deficient CaP layer that also incorporates Mg. The amorphous CaP apatite-like deposits promoted initial attachment, proliferation and osteogenic differentiation of bone marrow derived mesenchymal stem cells. Finally, we used our method to functionalise 3D porous structures of titanium alloy made by selective laser sintering. Our study uses a novel and cost-effective approach to functionalise clinically relevant metal surfaces in order to increase the bioactivity of these materials, which could improve their clinical performance.

Design of a Novel Two-Component Hybrid Dermal Scaffold for the Treatment of Pressure Sores

The aim of this study is to design a novel two-component hybrid scaffold using the fibrin/alginate porous hydrogel Smart Matrix combined to a backing layer of plasma polymerized polydimethylsiloxane (Sil) membrane to make the fibrin-based dermal scaffold more robust for the treatment of the clinically challenging pressure sores. A design criteria are established, according to which the Sil membranes are punched to avoid collection of fluid underneath. Manual peel test shows that native silicone does not attach to the fibrin/alginate component while the plasma polymerized silicone membranes are firmly bound to fibrin/alginate. Structural characterization shows that the fibrin/alginate matrix is intact after the addition of the Sil membrane. By adding a Sil membrane to the original fibrin/alginate scaffold, the resulting two-component scaffolds have a significantly higher shear or storage modulus G'. In vitro cell studies show that dermal fibroblasts remain viable, proliferate, and infiltrate the two-component hybrid scaffolds during the culture period. These results show that the design of a novel two-component hybrid dermal scaffold is successful according to the proposed design criteria. To the best of the authors' knowledge, this is the first study that reports the combination of a fibrin-based scaffold with a plasma-polymerized silicone membrane.

Psychometric properties of the English version of the Oral Health Literacy Adults Questionnaire - OHL-AQ

Objective

To test the psychometric properties of the Oral Health Literacy Adult Questionnaire (OHL-AQ) in English. The OHL-AQ was designed to test functional oral health literacy in general populations and was initially validated in Iran.

Methods

The instrument was administered to 405 adult subjects (mean age 45 (SD 16) years and 67% female) attending the 2014 Minnesota State Fair. The OHL-AQ is composed of 17 items measuring four conceptual dimensions: reading comprehension, numeracy, listening, and decision-making. Participants selected the best answer for written or verbally administered items and entered answers on an electronic tablet. Item responses for each individual were combined into a summary score (range 0-17) with higher scores indicating better oral health literacy. Score dimensionality, reliability, and validity were investigated.

Results

For dimensionality, both exploratory factor analysis and a parallel analysis yielded evidence for scale unidimensionality. Reliability was sufficient indicated by a Cronbach's alpha ⟩0.74. Validity of scores was supported by "small" and "medium" effect sizes for construct validity. "Small" effect sizes were observed for global oral health self-report, OHIP-5 scores, treatment urgency, and having a regular dentist. "Medium" effect sizes were seen for presence of dentures, number of natural teeth present, and educational level.

Conclusions

Dimensionality, reliability and validity of the English version of the OHL-AQ in a general adult English-speaking population is supported, providing sufficient psychometric properties in an important target population of the instrument.

Viscoelastic, physical, and bio-degradable properties of dermal scaffolds and related cell behaviour

Dermal scaffolds promote healing of debilitating skin injuries caused by burns and chronic skin conditions. Currently available products present disadvantages and therefore, there is still a clinical need for developing new dermal substitutes. This study aimed at comparing the viscoelastic, physical and bio-degradable properties of two dermal scaffolds, the collagen-based and clinically well established Integra(®) and a novel fibrin-based dermal scaffold developed at our laboratory called Smart Matrix(®), to further evaluate our previous published findings that suggested a higher influx of cells, reduced wound contraction and less scarring for Smart Matrix(®) when used in vivo. Rheological results showed that Integra(®) (G'  =  313.74 kPa) is mechanically stronger than Smart Matrix(®) (G'  =  8.26 kPa), due to the presence of the silicone backing layer in Integra(®). Micro-pores were observed on both dermal scaffolds, although nano-pores as well as densely packed nano-fibres were only observed for Smart Matrix(®). Average surface roughness was higher for Smart Matrix(®) (Sa  =  114.776 nm) than for Integra(®) (Sa  =  75.565 nm). Both scaffolds possess a highly porous structure (80-90%) and display a range of pore micro-sizes that represent the actual in vivo scenario. In vitro proteolytic bio-degradation suggested that Smart Matrix(®) would degrade faster upon implantation in vivo than Integra(®). For both scaffolds, the enzymatic digestion occurs via bulk degradation. These observed differences could affect cell behaviour on both scaffolds. Our results suggest that fine-tuning of scaffolds' viscoelastic, physical and bio-degradable properties can maximise cell behaviour in terms of attachment, proliferation and infiltration, which are essential for tissue repair.

An In Vitro Comparison of the Incorporation, Growth, and Chondrogenic Potential of Human Bone Marrow versus Adipose Tissue Mesenchymal Stem Cells in Clinically Relevant Cell Scaffolds Used for Cartilage Repair

AIM

To compare the incorporation, growth, and chondrogenic potential of bone marrow (BM) and adipose tissue (AT) mesenchymal stem cells (MSCs) in scaffolds used for cartilage repair.

METHODS

Human BM and AT MSCs were isolated, culture expanded, and characterised using standard protocols, then seeded into 2 different scaffolds, Chondro-Gide or Alpha Chondro Shield. Cell adhesion, incorporation, and viable cell growth were assessed microscopically and following calcein AM/ethidium homodimer (Live/Dead) staining. Cell-seeded scaffolds were treated with chondrogenic inducers for 28 days. Extracellular matrix deposition and soluble glycosaminoglycan (GAG) release into the culture medium was measured at day 28 by histology/immunohistochemistry and dimethylmethylene blue assay, respectively.

RESULTS

A greater number of viable MSCs from either source adhered and incorporated into Chondro-Gide than into Alpha Chondro Shield. In both cell scaffolds, this incorporation represented less than 2% of the cells that were seeded. There was a marked proliferation of BM MSCs, but not AT MSCs, in Chondro-Gide. MSCs from both sources underwent chondrogenic differentiation following induction. However, cartilaginous extracellular matrix deposition was most marked in Chondro-Gide seeded with BM MSCs. Soluble GAG secretion increased in chondrogenic versus control conditions. There was no marked difference in GAG secretion by MSCs from either cell source.

CONCLUSION

Chondro-Gide and Alpha Chondro Shield were permissive to the incorporation and chondrogenic differentiation of human BM and AT MSCs. Chondro-Gide seeded with BM MSCs demonstrated the greatest increase in MSC number and deposition of a cartilaginous tissue.

Human mesenchymal stem cells stimulate EaHy926 endothelial cell migration: combined proteomic and in vitro analysis of the influence of donor-donor variability

Mesenchymal stem cells (MSCs) stimulate angiogenesis within a wound environment and this effect is mediated through paracrine interactions with the endothelial cells present. Here we report that human MSC-conditioned medium (n=3 donors) significantly increased EaHy-926 endothelial cell adhesion and cell migration, but that this stimulatory effect was markedly donor-dependent. MALDI-TOF/TOF mass spectrometry demonstrated that whilst collagen type I and fibronectin were secreted by all of the MSC cultures, the small leucine rich proteoglycan, decorin was secreted only by the MSC culture that was least effective upon EaHy-926 cells. These individual extracellular matrix components were then tested as culture substrata. EaHy-926 cell adherence was greatest on fibronectin-coated surfaces with least adherence on decorin-coated surfaces. Scratch wound assays were used to examine cell migration. EaHy-926 cell scratch wound closure was quickest on substrates of fibronectin and slowest on decorin. However, EaHy-926 cell migration was stimulated by the addition of MSC-conditioned medium irrespective of the types of culture substrates. These data suggest that whilst the MSC secretome may generally be considered angiogenic, the composition of the secretome is variable and this variation probably contributes to donor-donor differences in activity. Hence, screening and optimizing MSC secretomes will improve the clinical effectiveness of pro-angiogenic MSC-based therapies.

Anatomic and Functional Outcome of Vaginal Paravaginal Repair in the Correction of Anterior Vaginal Wall Prolapse

Over a 2-year period 45 patients with bilateral paravaginal support defects underwent vaginal paravaginal repair. Postoperative evaluations were conducted and anatomic outcome was determined by vaginal examination, with grading of vaginal wall support. Functional outcome was assessed by a standardized quality of life questionnaire, voiding dairy and standing stress test with a full bladder. Thirty-five patients had long-term follow-up with a mean of 1.6 years (range 1-85). The recurrence rates for displacement cystocele, enterocele and rectocele were 3% (1/35), 20% (7/35) and 14% (5/35), respectively. In no patients did vault prolapse develop or recur. Subjective or objective evidence of persistent stress urinary incontinence was found in 57% of patients (12/21). Vaginal paravaginal repair is a safe and effective technique for the surgical correction of anterior vaginal wall prolapse but has limited applicability in the surgical correction of genuine stress incontinence.

MM-111: a novel bispecific antibody targeting ErbB3 with potent anti-tumor activity in ErbB2 over-expressing malignancies

Abstract #4166

ErbB3 has been identified as a preferred dimerization partner of ErbB2, critical for driving the proliferation of ErbB2 over-expressing breast tumors. We have designed a bispecific antibody, MM-111, which inhibits ligand-induced phosphorylation of ErbB3 with sub-nanomolar potency by exploiting the abundant expression of its dimerization partner, ErbB2, for specific targeting to cancer cells that express both receptors. We employed computational physicochemical modeling to guide the kinetic optimization of the monovalent binding affinities to the ErbB2 and ErbB3 receptors to increase the potency and specificity of MM-111 for tumor cells. We have demonstrated that MM-111 inhibits activation of the phosphatidylinositol 3-kinase pathway in vitro and in vivo, resulting in attenuation of tumor proliferation. Inhibition of growth by MM-111 has been observed in several murine xenograft models including BT474 and MDA-MB-361 breast tumors. While the antitumor activity of MM-111 is positively correlated with ErbB2 expression levels, MM-111's potent inhibition of ErbB3 phosphorylation and signaling downstream from this receptor differs markedly from currently available therapies targeting ErbB2 over-expressing breast tumors and thus provides a novel approach to treatment for these malignancies. In conclusion, our data demonstrate that the combination of computational biology with antibody engineering has resulted in the development of a promising, novel therapeutic, MM-111, that has potent antitumor activity in malignancies driven by the ErbB2/3 oncogenic unit.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 4166.

Tuberculous meningitis in BCG vaccinated and unvaccinated children

BACKGROUND

A modified clinical presentation of tuberculous meningitis (TBM) in children vaccinated with BCG has been described in the literature. However, most reports are old and not based on actual comparisons and tests of significance. Also, neuroimaging features were not compared. With large scale BCG coverage, it becomes pertinent to describe the "modified" presentation and identify any significant differences between vaccinated and unvaccinated children with TBM.

METHODS

A total of 150 consecutive hospitalised children (96 unvaccinated, 54 vaccinated) were enrolled. They all satisfied predefined criteria for diagnosis of TBM. Clinical and radiological features of children with/without a BCG scar were compared.

RESULTS

Univariate analysis revealed that the vaccinated children with TBM had significantly lower rates of altered sensorium (68.5% v 85.4% unvaccinated; OR 2.2 (1.1 to 6.2); p = 0.019) and focal neurological deficits (20.3% v 39.5% unvaccinated; OR 2.6 (1.1 to 6.0); p = 0.016), and higher mean (SD) Glasgow Coma Scale score (10.2 (3.4) v 8.76 (2.7) unvaccinated; p = 0.010) and cerebrospinal fluid cell count (210.9 v 140.9 unvaccinated; p = 0.019). No significant radiological differences were seen. Short term outcome was significantly better in the vaccinated group with 70% of the total severe sequelae and 75% of the total deaths occurring in the unvaccinated group (p = 0.018).

CONCLUSION

Children with TBM who have been vaccinated with BCG appear to maintain better mentation and have a superior outcome. This may in part be explained by the better immune response to infection, as reflected in the higher CSF cell counts in this group in the present study.

Dermal graft-augmented rectocele repair

We describe a new technique in the surgical treatment of rectocele using a dermal allograft to augment site-specific fascial defect repair of the rectovaginal fascia. The posterior vaginal wall is opened and discrete defects in the rectovaginal fascia are repaired in a site-specific fashion using delayed absorbable suture. A second layer of support is created using a rectangular dermal allograft placed over the site-specific repair and secured to the normal anatomic attachments of the rectovaginal fascia using permanent sutures. The vagina is then closed and routine perineorrhaphy performed as indicated. Forty-three women with advanced posterior vaginal wall prolapse underwent dermal graft augmentation of site-specific rectocele repair over a 1-year period. No major intraoperative or postoperative complications were reported. Thirty women were available for follow-up examination at an average of 12.9 months (range 8-17). The average patient age in the follow-up group was 63.6 +/- 10.9 years (range 33-79) and average parity was 2.8 +/- 1.5 (range 0-7). Using the Pelvic Organ Prolapse Quantification score, the average measurement of point A(p) was 0.25 preoperatively and -2.4 postoperatively, whereas point B(p )was 0.9 preoperatively and -2.5 postoperatively. Using a point A(p) measurement of -0.5 or greater to define surgical failure, 28/30 (93%) of women were noted to have surgical cure on follow-up. Site-specific rectocele repair augmented with dermal allograft is associated with high cure rates and minimal complications. It recreates normal anatomic support and is easily adapted into current surgical procedures for rectocele repair.

Repeat tension-free transvaginal tape (TVT) sling for the treatment of recurrent stress urinary incontinence

The pubovaginal sling is one of the preferred procedures for the treatment of female stress urinary incontinence because of its improved long-term cure rates. Recently a modified technique of the pubovaginal sling, known as the tension-free transvaginal tape (TVT), has gained popularity. We present the first reported cases of repeat TVT pubovaginal sling for the treatment of patients with recurrent stress urinary incontinence. Both patients had repeat TVT slings performed between 6 and 9 months following the initial procedure without revision or removal of the previous TVT sling. Both patients reported surgical cure without significant intraoperative or postoperative complications. It appears that reapplication of the TVT polypropolene sling may be a viable option in the event of initial TVT sling failure.

Tension-free vaginal tape: outcomes among women with primary versus recurrent stress urinary incontinence

OBJECTIVE

To evaluate the outcomes of tension-free vaginal tape in the treatment of primary versus recurrent genuine stress urinary incontinence.

METHODS

A retrospective, multicenter study of 245 consecutive women who were treated with tension-free vaginal tape for genuine stress urinary incontinence (157 for primary and 88 for recurrent genuine stress urinary incontinence) over a 27-month period was performed. Concurrent surgical repairs were performed as required. Subjective and objective outcome data were assessed from routine postoperative visits. Office and hospital records were reviewed to determine patient characteristics, intraoperative findings, and surgical outcomes.

RESULTS

Women with recurrent genuine stress urinary incontinence were older (mean age 64.6 versus 59.4 years, P =.004) than those with primary incontinence; they were less likely to have an intact uterus (22.7% versus 66.9%, P <.001), and were more likely to have intrinsic sphincter deficiency (70.5% versus 47.1%, P <.001). The mean duration of follow-up was 38 (+/-16) weeks. Cure rates among patients with recurrent versus primary genuine stress urinary incontinence were similar (85% and 87%, respectively, P =.23). Complication rates were similarly low in both groups (4.5% versus 7.6% for recurrent and primary genuine stress urinary incontinence, respectively, P =.35). Postoperative voiding dysfunction occurred at low rates in both groups.

CONCLUSION

Tension-free vaginal tape is a highly effective treatment among patients with recurrent stress incontinence, with outcomes comparable with those among patients with primary incontinence.

Release of tension-free vaginal tape for the treatment of refractory postoperative voiding dysfunction

OBJECTIVE

To report our experience with surgical release of tension-free vaginal tape (TVT) for the treatment of persistent post-TVT voiding dysfunction.

METHODS

A total of 1175 women underwent TVT placement for treatment of genuine stress urinary incontinence and/or intrinsic sphincter deficiency over a 2-year period. Additional procedures and vaginal repairs were performed as indicated. Among these patients, 23 women (1.9%) had persistent voiding dysfunction (urinary retention, incomplete bladder emptying, or severe urgency or urge incontinence) refractory to conservative management. This cohort underwent a simple vaginal TVT release procedure, performed on an outpatient basis. Preoperative characteristics, intraoperative, and postoperative details were assessed by review of operative notes, medical records, and office notes. Continence status was assessed using subjective and objective information.

RESULTS

Mean age was 67 years (range 46-86 years), and the mean interval between TVT placement and release was 17.3 weeks (range 2-69 weeks; median 8.6 weeks). For the release procedure, there were no intraoperative complications, and all patients were discharged on the day of surgery. All cases of impaired emptying were completely resolved, and all cases of irritative symptoms were resolved (30%) or improved (70%) by 6 weeks. Fourteen (61%) patients remained continent 6 weeks after the release procedure, six (26%) were improved over baseline, and three patients (13%) had recurrence of stress incontinence.

CONCLUSION

Refractory voiding dysfunction after TVT is a relatively uncommon situation and can be successfully managed with a simple midline release procedure. In most cases, the release procedure does not compromise overall improvement in symptoms of stress incontinence.

Levatorplasty release and reconstruction of rectovaginal septum using allogenic dermal graft

The goal of reconstructive vaginal surgery include: restoration of normal anatomy, as well as maintaining visceral and sexual function. Rectocele repair can be performed utilizing a number of techniques, however some of these techniques severely distort the posterior vaginal wall anatomy and subsequently may result in dyspareunia. We report two patients with postoperative dyspareunia following levatorplasty technique for the treatment of rectocele. The patients elected to have their levatorplasty released and their rectovaginal septum reconstructed utilizing allogenic dermal graft. Postoperatively both patients are sexually active without evidence of dyspareunia or rectocele.

Vaginal configuration on MRI after abdominal sacrocolpopexy and sacrospinous ligament suspension

An MRI study was conducted to compare the vaginal configuration of women who had undergone sacrospinous fixation with transvaginal needle suspension or abdominal sacrocolpopexy with retropubic colposuspension with that of normal controls. MRI examination demonstrated that in normal controls the lower vagina formed an acute angle (mean 53 degrees) with the pubococcygeal line and intersected the upper vagina at a mean angle of 145 degrees. In the abdominal repair group the lower vagina intersected the pubococcygeal line at a mean angle of 57 degrees and joined the upper segment at a mean angle of 137 degrees. In the vaginal repair group the lower vagina intersected the pubococcygeal line at a mean angle of 54 degrees and joined the upper segment at a mean angle of 220 degrees. Our study demonstrated that abdominal sacrocolpopexy with retropubic colposuspension more closely restored the vagina to its normal configuration, whereas sacrospinous fixation with transvaginal needle suspension creates an abnormal vaginal axis.

Ethical issues surrounding separation of conjoined twins

Conjoined twins are a rare occurrence, with an incidence of about 1 in 250,000 live births. Approximately 60% are stillborn. Though they can be joined at the hip, abdomen, chest, or head, the majority are joined at the chest, and share a heart. Although they are fascinating to the public, conjoined twins present complex and challenging ethical, medical, and legal issues to all of those involved in their care. Among the issues discussed here are: right to life, presumed consent, physician duty, quality of life, allocation of resources, and futile care. This paper also discusses the pros and cons of separation and then offers alternative solutions.

Use of synthetic mesh and donor grafts in gynecologic surgery

Traditional surgery for the correction of pelvic organ prolapse continues to result in suboptimal long-term cure rates. In an effort to improve clinical outcomes, various new surgical techniques have been proposed and use of synthetic and donor graft has been advocated. Although the technique of graft placement for the correction of anterior, posterior, and apical vaginal wall reconstruction is easy to perform, controversy exists regarding the optimal choice of material. Synthetic materials have the advantage of being readily available, cost-effective, and consistent in quality, but may present with significant complications, including infection and erosion. In contrast, autologous and heterologous donor grafts provide naturally occurring biomaterials that may undergo desired remodelling, but the in vivo tissue response is still not fully understood. The use of graft materials is still in an early period of evaluation and it is expected that its use will steadily rise with increasing experience and new product development. The following review analyzes our current experience with the use of graft materials in reconstructive pelvic surgery.

Laparoscopic management of urinary incontinence, ureteric and bladder injuries

The present review focuses on the most recently published English language literature, and addresses results and complications associated with the laparoscopic approach to urinary incontinence, anterior vaginal wall prolapse, and lower urinary tract injury. Laparoscopic Burch procedures continue to show equal efficacy, but lower morbidity as compared with conventional open techniques. Lower urinary tract injuries may also be managed effectively using the same techniques as those employed in open procedures. Laparoscopy continues to be considered a mode of surgical access, and is effective in treating urinary incontinence, anterior vaginal wall prolapse, and lower urinary tract injuries.

Laparoscopic paravaginal repair plus burch colposuspension: review and descriptive technique

The objective of this article was to review the available literature on laparoscopic Burch urethropexy cure rates and describe the authors' laparoscopic technique and experience with Burch urethropexy and paravaginal repair. A MEDLINE search (1991 to 1999) was performed for articles describing the laparoscopic Burch urethropexy using suture to elevate and stabilize the paraurethral tissue. Also a retrospective chart review of the authors' 171 consecutive patients between January 1997 and December 1999 was done. The laparoscopic Burch urethropexy and paravaginal repair is described using an open laparoscopic technique with 3 accessory ports for access. A transperitoneal approach is taken to gain access to the space of Retzius. The anterior vaginal wall and its paravaginal defects, if present, are identified. Nonabsorbable sutures are placed in a conventional fashion. The paravaginal repair is used for support of the anterior vaginal wall proximal to the urethral vesical junction and the Burch urethropexy distal to the vesical neck. An average of 6 sutures are used for the paravaginal repair and 4 sutures for the Burch urethropexy. Cystoscopy is performed to ensure no breech of lower urinary tract integrity. In all, 20 articles describing a laparoscopic Burch urethropexy and postoperative cure rate were identified. Cure rates ranged from 69% to 100%. A review of our experience revealed 130 of 171 patients had a Burch urethropexy and paravaginal repair, 23 of 171 patients a Burch urethropexy alone, and 18 of 171 patients a paravaginal repair alone. Of the authors' 171 patients, 4 (2.3%) had injury to the lower urinary tract during laparoscopic Burch urethropexy or paravaginal repair. All 4 injuries were cystotomies, 2 in patients with previous open retropubic urethropexies. No ureteral ligations or intravesical placement of suture was diagnosed. Other surgical parameters for the laparoscopic Burch uethropexy and paravaginal repair include an estimated blood loss of 50 mL, average hospital stay of less than 23 hours, and an average operative time of 70 minutes. All patients had their surgery completed via laparoscopy. The literature review and our personal experience suggests that the laparoscopic Burch urethropexy and paravaginal repair are safe and effective alternatives to traditional laparotomy for the treatment of genuine anatomic stress urine incontinence and cystourethrocele resulting from lateral vaginal wall defects.

Routine hematocrit after elective gynecologic surgery

OBJECTIVE

To determine the clinical use and associated costs of routine postoperative hematocrit after elective gynecologic surgery.

METHODS

We reviewed the charts of all women who had elective gynecologic surgery over 12 months at a community hospital. Demographic data, estimated blood loss at surgery, pre- and postoperative hematocrits, postoperative symptoms suggesting anemia, and incidence of transfusion were tabulated. Laboratory charges for hematocrit at the hospital were used to develop an economic assessment. Statistical analysis was done with Student t test, Mann-Whitney U test, and Fisher exact test.

RESULTS

Among 1105 women who had elective surgery, a single postoperative hematocrit was done in 761 (69%) and two or more postoperative hematocrits (mean 2.4, range 2-6) were done in 201 (18%). The overall incidence of blood transfusion related to elective gynecologic surgery was 1.9% (21 of 1105). Five of those women needed preoperative transfusions, eight needed intraoperative transfusions, and the remaining eight had postoperative transfusions. All women who needed postoperative transfusion showed some sign or symptom of anemia. None received transfusions based solely on hematocrit. Risk factors for postoperative transfusion included low preoperative hematocrit and increased intraoperative blood loss.

CONCLUSION

Routine postoperative hematocrit in asymptomatic women after uncomplicated elective gynecologic surgery did not improve outcome.

Periurethral collagen injection for stress incontinence with and without urethral hypermobility

OBJECTIVE

To compare the use of periurethral collagen injection in the treatment of female stress urinary incontinence due to intrinsic sphincter deficiency in women with and without urethral hypermobility.

METHODS

A retrospective review was performed of 60 periurethral collagen injections performed on 40 consecutive women from January 1996 to December 1997. A review of the office chart and operative notes was performed to obtain demographic, urodynamic, and procedural data. Outcome data were obtained by personal or telephone interview, using patients' subjective assessments including an analog satisfaction scale.

RESULTS

Nine of 40 patients (23%) had urethral hypermobility. Compared with patients without hypermobility, patients with hypermobility required a similar number of procedures (a mean of 1.9 compared with 1.4, P = .13) and required similar amounts of collagen on the first injection (5.6 mL compared with 5.3 mL, P = .69). Preoperative urodynamic parameters were similar in both groups. Rates of subjective dryness were equivalent in patients with and without hypermobility at 1 month (76% and 46%, P = .24) and at 6 months (71% and 32%, P = .09) following initial injection. A post hoc power analysis was performed to evaluate the primary study measures of continence at 1 and 6 months, and number of collagen injections. This revealed that a sample size of 40 patients would be sufficient to detect a 2.5-fold difference in number of injections and a 3-fold difference in subjective dryness.

CONCLUSION

Coexisting urethral hypermobility should not preclude the use of collagen injections in women with stress urinary incontinence.

Periurethral collagen injection for stress incontinence with and without urethral hypermobility

OBJECTIVE

To compare the use of periurethral collagen injection in the treatment of female stress urinary incontinence due to intrinsic sphincter deficiency in women with and without urethral hypermobility.

METHODS

A retrospective review was performed of 60 periurethral collagen injections performed on 40 consecutive women from January 1996 to December 1997. A review of the office chart and operative notes was performed to obtain demographic, urodynamic, and procedural data. Outcome data were obtained by personal or telephone interview, using patients' subjective assessments including an analog satisfaction scale.

RESULTS

Nine of 40 patients (23%) had urethral hypermobility. Compared with patients without hypermobility, patients with hypermobility required a similar number of procedures (a mean of 1.9 compared with 1.4, P = .13) and required similar amounts of collagen on the first injection (5.6 mL compared with 5.3 mL, P = .69). Preoperative urodynamic parameters were similar in both groups. Rates of subjective dryness were equivalent in patients with and without hypermobility at 1 month (76% and 46%, P = .24) and at 6 months (71% and 32%, P = .09) following initial injection. A post hoc power analysis was performed to evaluate the primary study measures of continence at 1 and 6 months, and number of collagen injections. This revealed that a sample size of 40 patients would be sufficient to detect a 2.5-fold difference in number of injections and a 3-fold difference in subjective dryness.

CONCLUSION

Coexisting urethral hypermobility should not preclude the use of collagen injections in women with stress urinary incontinence.