The effect of bisphosphonate treatment on the biochemical and cellular events during bone remodelling in response to microinjury stimulation

Osteoporosis is one of the most prevalent bone diseases worldwide and is characterised by high levels of bone turnover, a marked loss in bone mass and accumulation of microdamage, which leads to an increased fracture incidence that places a huge burden on global health care systems. Bisphosphonates have been used to treat osteoporosis and have shown great success in conserving bone mass and reducing fracture incidence. In spite of the existing knowledge of the in vivo responses of bone to bisphosphonates, the cellular responses to these drugs have yet to be fully elucidated. In vitro model systems that allow the decoupling of complex highly integrated events, such as bone remodelling, provide a tool whereby these biological processes may be studied in a more simplified context. This study firstly utilised an in vitro model system of bone remodelling and comprising all three major cell types of the bone (osteocytes, osteoclasts and osteoblasts), which was representative of the bone's capacity to sense microdamage and subsequently initiate a basic multicellular unit response. Secondly, this system was used to study the effect of two commonly utilised aminobisphosphonate treatments for osteoporosis, alendronate and zoledronate. We demonstrated that microinjury to osteocyte networks being treated with bisphosphonates modulates receptor activator of nuclear factor kappa-B ligand and osteoprotegerin activity, and subsequently osteoclastogenesis. Furthermore, bisphosphonates increased the osteogenic potential following microinjury. Thus, we have shown for the first time that bisphosphonates act at all three stages of bone remodelling, from microinjury to osteoclastogenesis and ultimately osteogenesis.

Quantification of liver herniation in fetuses with isolated congenital diaphragmatic hernia using two-dimensional ultrasonography

OBJECTIVES

To describe a method of quantifying the amount of liver herniation in fetuses with isolated congenital diaphragmatic hernia (CDH) using two-dimensional ultrasonography and to correlate this finding with neonatal outcome.

METHODS

Ultrasound images obtained from 77 consecutive fetuses that presented with isolated CDH between January 2004 and July 2012 were reviewed. Liver herniation and thoracic area were measured in a cross-sectional plane of the fetal chest at the level of the four-chamber view of the heart (the same section as is used to measure the lung area-to-head circumference ratio) and the ultrasound-derived liver-to-thoracic area ratio (US-LiTR) was calculated by dividing the liver herniation area by the thoracic area. Receiver-operating characteristics (ROC) curve analysis was used to evaluate the performance of US-LiTR in predicting neonatal outcome (survival to 6 months after delivery and need for extracorporeal membrane oxygenation (ECMO)). In addition, the US-LiTR was compared with the magnetic resonance imaging (MRI)-derived volume ratio (MRI-LiTR) and percentage of liver herniation (MRI-%LH).

RESULTS

The overall neonatal mortality in the 77 cases with isolated CDH was 20.8% (16/77). ECMO was needed in 35.5% (27/76) of the newborns, with a survival rate of 52%. The US-LiTR was associated statistically with mortality (P < 0.01) and with the need for ECMO (P < 0.01). Good correlations were observed between US-LiTR and MRI-LiTR (r = 0.87; P < 0.001) and between US-LiTR and MRI-%LH (r = 0.90; P < 0.001). Based on ROC curve analysis, all three parameters had similar accuracy in predicting mortality (US-LiTR: area under the ROC curve (AUC), 0.78 (95% CI, 0.65-0.92), P < 0.01; MRI-LiTR: AUC, 0.77 (95% CI, 0.63-0.90), P < 0.01; MRI-%LH: AUC, 0.79 (95% CI, 0.65-0.92), P < 0.01, respectively) as well as the need for ECMO (US-LiTR: AUC, 0.72 (95% CI, 0.60-0.84), P < 0.01; MRI-LiTR: AUC, 0.73 (95% CI, 0.60-0.88), P < 0.01; MRI-%LH: AUC, 0.77 (95% CI, 0.64-0.89), P < 0.01, respectively).

CONCLUSIONS

Two-dimensional ultrasound measurement of the amount of liver herniation in fetuses with isolated CDH is feasible and demonstrates a predictive accuracy for neonatal outcome similar to that of MRI.

Congenital heart anomaly in newborns with congenital diaphragmatic hernia: a single-center experience

OBJECTIVE

To evaluate the impact of the presence of a congenital heart anomaly (CHA) and its potential contribution to morbidity and mortality in infants with congenital diaphragmatic hernia (CDH).

METHODS

In this retrospective cohort study, prenatal and postnatal data of all newborns diagnosed with CDH between January 2004 and December 2012 in a single center were reviewed. Cases were classified into two groups: those with 'isolated' CDH and those with both CDH and CHA. Patients with CHA were further subclassified into those with a major or minor CHA based on the Risk Adjustment for Congenital Heart Surgery-1 (RACHS-1), and the Society of Thoracic Surgeons-European Association for Cardiothoracic Surgery (STS-EACTS) scoring systems. Patients with associated non-cardiac anomalies, including 'syndromic cases', were excluded from the analysis. Primary and secondary outcomes were survival up to 1 year of age and a need for extracorporeal membrane oxygenation (ECMO), respectively.

RESULTS

Of the 180 infants with CDH, 41 were excluded because of the presence of non-cardiac associated anomalies, 118 had isolated CDH and 21 had CDH with CHA (16 with minor and five with major CHA). Receiver-operating characteristics curve analysis demonstrated that the best cut-off for survival was when the score for CHA was ≤ 2 for both RACHS-1 (area under the curve (AUC), 0.74 (P = 0.04); sensitivity, 80.0%; specificity, 87.5%) and STS-EACTS (AUC, 0.83 (P = 0.03); sensitivity, 100%; specificity, 87.5%). Survival rate at 1 year was significantly lower in those with CHD and a major CHA (40.0%; P = 0.04) than in those with isolated CDH (77.1%) and those with CDH and a minor CHA (81.3%). We found no significant differences among the groups with regard to the need for ECMO.

CONCLUSIONS

In general, a milder form of CHA does not appear to have a negative impact on the survival of infants with CDH. However, mortality appears to be significantly higher in infants with CDH and a major form of CHA. The scoring systems appear to be useful as predictors for classifying the effects of CHA in this population of patients.

Realgar (As4S4) nanoparticles and arsenic trioxide (As2O3) induced autophagy and apoptosis in human melanoma cells in vitro

The aim of the present study was to compare the effect of realgar nanoparticles and arsenic trioxide (ATO) on viability, DNA damage, proliferation, autophagy and apoptosis in the human melanoma cell lines BOWES and A375. The application of various flow cytometric methods for measurements cell viability, DNA cell cycle, mitochondrial potential, lysosomal activity, and intracellular content of glutathione was used. In addition, quantitative PCR, western blotting and multiplex bead array analyses were applied for evaluation of redox stress, autophagic flux, and cell signaling alterations.The results showed that realgar treatment of studied cells caused modulation of cell proliferation, induced a block in G2/M phase of the cell cycle and altered phosphorylation of IκB, Akt, ERK1/2, p38, and JNK kinases, as well as decreased mitochondrial membrane potential. Additionally, it appeared that induction of cell death by both realgar and ATO was dose-dependent, when lower (0.3 µM) dosage increased lysosomal activity and induced autophagy and higher (1.25 µM) concentration resulted in the appearance of apoptosis, while pan-caspase inhibitor attenuated more efficiently realgar- than ATO-induced cell death. Furthermore, low concentrations of ATO and realgar nanoparticles increased the content of intracellular glutathione and elevated γ-H2AX expression confirmed DNA damage preferentially at higher concentrations of both drugs used. Further analysis revealed slight differences in time-dependent phosphorylation pattern due to both realgar and ATO treatments, while significant differences were noticed between cell lines. In conclusion, realgar nanoparticles and ATO treatment induced dose-dependent activation of autophagy and apoptosis in both melanoma cell lines, when autophagy flux was determined at lower drug concentrations and the switch to apoptosis occurred at higher concentrations of both arsenic forms.

Early postoperative imaging and image-guided procedures on patients with face transplants

Face transplantation is being performed with increasing frequency. Facial edema, fluid collections, and lymphadenopathy are common postoperative findings and may be due to various etiologies, some of which are particular to face transplantation. The purpose of this study was to demonstrate how postoperative imaging and image-guided minimally invasive procedures can assist in diagnosing and treating complications arising from face transplantation. Retrospective evaluation of 6 consecutive cases of face transplantation performed at Brigham and Women's Hospital between April 2009 and March 2014 was performed with assessment of postoperative imaging and image-guided procedures, including aspiration of postoperative fluid collection, lymph node biopsy, and treatment of salivary gland leak. Through these cases, we demonstrate that early postoperative imaging and image-guided procedures are key components for the management of complications following face transplantation.

Fetal lung volume and quantification of liver herniation by magnetic resonance imaging in isolated congenital diaphragmatic hernia

OBJECTIVE

To determine associations between fetal lung and liver herniation volumes measured by magnetic resonance imaging (MRI) and mortality/need for extracorporeal membrane oxygenation (ECMO) in cases of isolated congenital diaphragmatic hernia (CDH). A secondary objective was to compare prenatal MRI parameters with two-dimensional ultrasound lung measurements.

METHODS

A retrospective review of medical records of all fetuses with isolated CDH evaluated between January 2004 and July 2012 was performed. The following MRI parameters were measured at 20-32 weeks: observed/expected total fetal lung volume (o/e-TLV), predicted pulmonary volume (PPV), percentage of liver herniated into the fetal thorax (%LH) and the liver/thoracic volume ratio (LiTR). These were compared with the ultrasound-determined lung-to-head ratio (LHR) and the observed/expected LHR (o/e-LHR) in the same cohort. The predictive value of MRI and ultrasound parameters for mortality and the need for ECMO was evaluated by univariate, multivariate and factor analysis and by receiver-operating characteristics curves.

RESULTS

Eighty fetuses with isolated CDH were evaluated. Overall mortality was 18/80 (22.5%). Two newborns died a few hours after birth. ECMO was performed in 29/78 (37.2%) newborns, with a survival rate of 48.3% (14/29). The side of the diaphragmatic defect was not associated with mortality (P = 0.99) or the need for ECMO (P = 0.48). Good correlation was observed among o/e-TLV, PPV, LHR and o/e-LHR as well as between %LH and LiTR (r = 0.89; P < 0.01); however, fetal lung measurements and measures of liver herniation were not correlated (all P > 0.05). All parameters were statistically associated with mortality or the need for ECMO. The best combination of measurements to predict mortality was o/e-TLV and %LH, with 83% accuracy.

CONCLUSION

Mortality and the need for ECMO in neonates with isolated CDH can be best predicted using a combination of MRI o/e-TLV and %LH.

Systematic review with network meta-analysis: the efficacy of anti-TNF agents for the treatment of Crohn's disease

BACKGROUND

Anti-tumour necrosis factor-alpha agents (anti-TNF) are effective therapies for the treatment of Crohn's disease (CD), but their comparative efficacy is unknown.

AIM

To perform a network meta-analysis comparing the efficacy of anti-TNF therapies in CD.

METHODS

After screening 506 studies, reviewers extracted information on 10 studies. Traditional meta-analysis (TMA) was used to compare each anti-TNF agent to placebo. Bayesian network meta-analysis (NMA) was performed to compare the effects of anti-TNF agents to placebo. In addition, sample sizes for comparative efficacy trials were calculated.

RESULTS

Compared to placebo, TMA revealed that anti-TNF agents result in a higher likelihood of induction of remission and response (RR: 1.66, 95% CI: 1.17-2.36 and RR: 1.43, 95% CI: 1.17-1.73, respectively) as well as maintenance of remission and response (RR: 1.78, 95% CI: 1.51-2.09 and RR: 1.68, 95% CI: 1.46-1.93, respectively). NMA found nonsignificant trends between infliximab and adalimumab or certolizumab pegol. Among subcutaneous therapies, NMA demonstrated superiority of adalimumab to certolizumab pegol for induction of remission (RR: 2.93, 95% CrI: 1.21-7.75). Sample size calculations suggest that adequately powered head-to-head comparative efficacy trials would require greater than 3000 patients.

CONCLUSIONS

All anti-TNF agents are effective for induction and maintenance of response and remission in the treatment of CD. Although adalimumab is superior to certolizumab pegol for induction of remission, there is no evidence of clinical superiority among anti-TNF agents. Head-to-head trials among the anti-TNF agents are impractical in terms of size and cost.

Fatigue failure of osteocyte cellular processes: implications for the repair of bone

The physical effects of fatigue failure caused by cyclic strain are important and for most materials well understood. However, nothing is known about this mode of failure in living cells. We developed a novel method that allowed us to apply controlled levels of cyclic displacement to networks of osteocytes in bone. We showed that under cyclic loading, fatigue failure takes place in the dendritic processes of osteocytes at cyclic strain levels as low as one tenth of the strain needed for instantaneous rupture. The number of cycles to failure was inversely correlated with the strain level. Further experiments demonstrated that these failures were not artefacts of our methods of sample preparation and testing, and that fatigue failure of cell processes also occurs in vivo. This work is significant as it is the first time it has been possible to conduct fatigue testing on cellular material of any kind. Many types of cells experience repetitive loading which may cause failure or damage requiring repair. It is clinically important to determine how cyclic strain affects cells and how they respond in order to gain a deeper understanding of the physiological processes stimulated in this manner. The more we understand about the natural repair process in bone the more targeted the intervention methods may become if disruption of the repair process occurred. Our results will help to understand how the osteocyte cell network is disrupted in the vicinity of matrix damage, a crucial step in bone remodelling.

Holistic management of venous ulcers especially with endovenous laser treatment using 980nm laser in an ethnically diverse society

AIM

Chronic venous ulcers usually occur as an occupational hazard due to venous insufficiency with venous hypertension. Endovenous laser treatment (EVT) is used to treat varicose veins with venous ulcers and outcome including demography assessed in the different races.

PROCEDURE

145 lower limbs(right 39.3%, left 60.7%) with venous ulcers involving reflux of the great saphenous (132 cases) and / or small saphenous (57 cases) veins underwent EVT with 980 nm diode laser for single (123 cases) or both (11 cases) legs intervention. Supplementary procedures required multiple avulsions and / or sclerotherapy. Holistic advice of multilayered bandaging, graduated compression stockings, weight reduction and lifestyle changes enforced.

RESULT

The average age with venous ulcers was 53.6 years.The mean BMI was 26.8 : the Chinese, Indian and Malay BMIs were 25.1, 28.1 and 31.3 respectively. Symptoms that included pain, swelling, heaviness and cramps assessed pre- and postsurgically were significantly reduced (<0.0001), using the Wilcoxan signed rank test. Of the occupations involved by race, the Chinese were mostly salespersons, Indians blue collar workers and Malays foodrelated workers. Young overweight Indians with sedentary occupations were most predisposed to venous ulcers. Gram negative organisms 63.4% and gram positive organisms 36.6% were isolated in the ulcers. Most ulcers 63.5% measured <2 cm and majority 73.8% localised in the gaiter area.

DISCUSSION

Results of EVT in healing ulcers with no recurrences more than 2 years were successful in 89.7% (130/145). Complications included numbness foot 7.5% and DVT 1.4%. 10.3% (15 cases) had recurrence of venous ulcers within 2 years. In terms of satisfaction 32.3% experienced as very satisfied while 63.4% were satisfied and 4.3% unsatisfied. In conclusion EVT is a useful adjunct with with minimal invasion in managing venous ulcers holistically.

Rotavirus activity and meteorological variations in an Asian subtropical city, Hong Kong, 1995-2009

Rotavirus is a leading cause of severe infectious diarrhea in infants and young children aged <5 years. Rotavirus infections have minimal to strong seasonality depending on geographical locations. In this study, a comprehensive retrospective analysis was performed to evaluate the association between rotavirus admission and multiple key meteorological variables, including air temperature, relative humidity, atmospheric pressure, and solar radiation over a 15-year period from 1995 to 2009 in Hong Kong. Rotavirus infections were found to show a distinct cyclical pattern with an annual peak in cold season. The weekly number of cases showed the strongest correlation with average air temperature of the previous 7 days (rho=-0.69; P<0.0001), followed by atmospheric pressure (rho=+0.67; P<0.0001); whereas only weak correlation with relative humidity (rho=-0.252; P<0.0001) and solar radiation (rho=-0.312; P<0.0001) was observed. Curve fitting regression analysis suggested that the correlation was nonlinear in nature in which the effect was more profound towards lower air temperature and higher atmospheric pressure conditions. In binary logistic regression analysis, a final model that included air temperature (≤ 20°C) and atmospheric pressure (≥ 1,013 hPa) predicted correctly 85.3% and 82.6% of weeks with rotavirus activity above and below the baseline level, respectively. In multivariate Poisson model, air temperature and solar radiation were independent factors associated with the weekly number of rotavirus cases, adjusted for seasonal variation. In summary, the current study provides evidence suggesting that local seasonal activity of rotavirus correlated strongly with air temperature, followed by atmospheric pressure but only minimally with relative humidity in pre-vaccine era.

Examination of osteoarthritis and subchondral bone alterations within the stifle joint of an ovariectomised ovine model

The exact relationship between osteoporosis and osteoarthritis is still a matter for debate for many. The ovariectomised ewe is frequently used as a model for osteoporosis, resulting in significant alterations in bone morphometry and turnover in both trabecular and subchondral bone after 1 year. This study examines whether ovariectomy has any impact on development of osteoarthritis within the ovine stifle joint at the same time point. In addition, we investigate whether there are any significant correlations present between articular cartilage degeneration and alterations in microstructural parameters or turnover rates in the underlying bone. Twenty-two sheep were examined in this study; 10 of the sheep underwent ovariectomy and 12 were kept as controls. Five distinctive fluorochrome dyes were administered intravenously at 12-week intervals to both groups, to label sites of bone turnover. All animals were then sacrificed 12 months postoperatively. Although most specimens showed some evidence of osteoarthritis, no measurable difference between the two study groups was detected. Osteoarthritis was associated with a thinning of the subchondral plate, specifically the subchondral cortical bone; however, whereas previous studies have suggested a link between trabecular thinning and osteoarthritis, this was not confirmed. No correlation was found between osteoarthritis and bone turnover rates of either the subchondral trabecular bone or bone plate. In conclusion, despite the fact that ovariectomy results in marked morphological and structural changes in the ovine stifle joint at 1-year postoperatively, no evidence was found to suggest that it plays a direct role in the aetiology of osteoarthritis.

Subchondral osteopenia and accelerated bone remodelling post-ovariectomy - a possible mechanism for subchondral microfractures in the aetiology of spontaneous osteonecrosis of the knee?

Osteopenia and subchondral microfractures are implicated in the aetiology of spontaneous osteonecrosis of the knee (SPONK). The ovine tibia shows significant alterations of the trabecular architecture within the subchondral bone of the medial tibial plateau post-ovariectomy (OVX), including reduced trabecular bone volume fraction. We hypothesise that accelerated subchondral bone resorption may also play a role in increasing microfracture risk at this site. Twenty-two sheep were examined in this study; 10 of the sheep underwent OVX, while the remainder (n = 13) were kept as controls (CON). Five fluorochrome dyes were administered intravenously at 12-week intervals via the jugular vein to both groups, to label sites of bone turnover. These animals were then killed at 12 months post-operatively. Bone turnover was significantly increased in the OVX group in both trabecular bone (2.024 vs. 1.047 no. mm(-2) ; P = 0.05) and within the subchondral bone plate (4.68 vs. 0.69 no. mm(-2) ; P < 0.001). In addition to the classically described turnover visible along trabecular surfaces, we also found visual evidence of intra-trabecular osteonal remodelling. In conclusion, this study shows significant alterations in bone turnover in both trabecular bone and within the subchondral bone plate at 1 year post-OVX. Remodelling of trabecular bone was due to both classically described hemi-osteonal and intra-trabecular osteonal remodelling. The presence of both localised osteopenia and accelerated bone remodelling within the medial tibial plateau provide a possible mechanism for subchondral microfractures in the aetiology of SPONK. Further utilisation of the OVX ewe may be useful for further study in this field.

Zuckerkandl tubercle of the thyroid: a common imaging finding that may mimic pathology

BACKGROUND AND PURPOSE

The posterior thyroid tubercle, also known as ZT, is an important surgical landmark due to its close proximity to the recurrent laryngeal nerve. A recent case of ZT with a nodular configuration caused clinical concern but was shown on biopsy to be normal thyroid tissue. The purpose of this study was to review a series of CT neck studies to identify how often ZT-specifically, a nodular subtype-was present.

MATERIALS AND METHODS

A total of 96 neck CTs from sequential patients were retrospectively identified from January 2010 to July 2010. ZT was defined on imaging as a thyroid lobe extending posterior to the tracheoesophageal groove. A nodular subtype was defined as having a narrowed neck at the level of the tracheoesophageal groove.

RESULTS

There were 31 women and 45 men (mean age of 56.1 years, range 22-100 years) who met inclusion criteria. Sixty-seven patients had thyroid glands that extended posterior to the tracheoesophageal groove at CT imaging; this finding was bilateral in 43 patients, more commonly on the right (60 versus 49). Thirty-two of these patients (42.1%; 16 male, 16 female) had a nodular subtype.

CONCLUSIONS

ZT is an important surgical landmark of the thyroid that has important radiologic variations. It has a nodular shape in over a third of CT neck studies in our series. Recognition of this feature of the thyroid gland at CT imaging can obviate the need for biopsy and avoid potential recurrent laryngeal nerve injury.

An experimental study on costal osteochondral graft

OBJECTIVE

To investigate usefulness of osteochondral grafting from the costo-osteochondral junction as a repair technique for articular cartilage defects histologic and biochemical analysis of grafted cartilage in rabbit knees was evaluated up to 48 weeks after transplantation.

METHODS

Twenty New Zealand White rabbits were used. A costal osteochondral plug was harvested from a middle rib. After trimming, it was transplanted into a cylindrical osteochondral 2.5 mm diameter and 5 mm deep defect created in the knee. The animals were sacrificed at 6, 12, 24, and 48 weeks after transplantation. Defect sites were inspected macroscopically, and then by light microscopy. Samples were evaluated for cell viability using a fluorescent in situ double-staining protocol with confocal laser microscopic analysis. Samples were also processed to assess type I & II collagen and aggrecan mRNA expression using reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS

Histologically, bone union was achieved in all plugs. Confocal microscopic analysis revealed chondrocyte viability in the 48-week grafts; the distribution of chondrocytes was similar to surrounding articular cartilage. The expression of type II collagen and aggrecan mRNA in the grafted cartilage was consistent with normal articular cartilage and normal costal cartilage. These results were observed over 6-48 weeks.

CONCLUSIONS

Our study revealed that chondrocytes in the grafted cartilage were viable at least up to 48 weeks and that mRNA expression of type II collagen and aggrecan was also similar to that of normal articular cartilage. These results suggest that costal osteochondral grafting can be a useful alternative in the treatment of osteochondral defects.

Lung function and respiratory symptoms in a 1-year randomized smoking cessation trial of varenicline in COPD patients

There are few data concerning changes in lung function and respiratory symptoms in smokers with chronic obstructive pulmonary disease (COPD) weeks to months after quitting smoking. We examined serial changes in spirometry and Clinical COPD Questionnaire (CCQ) scores (measuring respiratory symptoms and health-related quality of life) in COPD participants by smoking status during a smoking cessation trial. In this randomized, double-blind trial, smokers with mild-to-moderate COPD were treated with varenicline 1 mg b.i.d. or placebo for 12 weeks and followed to Week 52. Primary endpoints of abstinence were previously reported. Secondary endpoints were mean changes from baseline in post-bronchodilator forced expired volume in 1 s (FEV(1)) and CCQ scores. Change from baseline in post-bronchodilator FEV(1) was significantly improved in continuous abstainers (121.8 mL) vs. continuous smokers (37.9 mL) at Week 12 (P = 0.0069), but not at Weeks 24 or 52. Mean change from baseline at Week 12 in CCQ Total Score was significantly better in continuous abstainers (-1.04) vs. continuous smokers (-0.53; P < 0.0001): this improvement was sustained at Weeks 24 and 52. In a 1-year cessation trial of smokers with COPD, continuous abstinence compared with continuous smoking significantly improved post-bronchodilator FEV(1) at Week 12 (although the difference narrowed subsequently) and CCQ Total Scores at Week 12, with sustained improvement thereafter. (

TRIAL REGISTRY

http://www.clinicaltrials.gov; trial identifier: NCT00285012).

Subchondral trabecular structural changes in the proximal tibia in an ovine model of increased bone turnover

Ovariectomized (OVX) sheep are now considered to be useful models for a variety of metabolic bone disorders. The specific aim of this study was to determine the effects of ovariectomy on the structural parameters and material density of the subchondral bone of the ovine tibial plateau as measured by microcomputed tomography (MicroCT). Twenty-three sheep were examined in this study; 10 of the sheep underwent ovariectomy (OVX), and the remainder (n=13) were kept as controls (CON). These animals were then sacrificed at 12 months post-operatively. Three-dimensional analyses were performed of osteochondral samples (15 mm deep) which were obtained from the medial tibial plateau using MicroCT. Bone volume fraction of the subchondral trabecular bone was reduced in the ovariectomized sheep as compared to control animals (0.439 vs. 0.483, P=0.038). Trabeculae were also significantly thinner in the OVX group (0.220 vs. 0.252 mm, P=0.010), with reduced connectivity density (7.947 vs. 11.524 mm(-3) , P=0.014). There was a trend towards lower numbers of individual trabeculae present in the OVX group as compared to controls, but this did not reach significance (2.817 vs. 3.288 mm(-1) , P=0.1). There was also increased trabecular separation in the OVX group, which again fell short of significance (0.426 vs. 0.387 mm, P=0.251). There was no difference in hydroxyapatite concentration (HA) between the two groups (929 vs. 932 mgHA cm(-3) , P=0.687). In conclusion, significant alterations of the trabecular architecture under the tibial plateau were observed following 12 months of oestrogen-deficiency in this ovine model. Despite these marked morphological and structural density differences, the material densities were equal in the two groups.

The effects of estrogen deficiency and bisphosphonate treatment on tissue mineralisation and stiffness in an ovine model of osteoporosis

While much research has been dedicated to understanding osteoporosis, the nature of mineral distribution and the mechanical property variation in diseased bone is poorly understood. The current study aimed to determine the effect of estrogen deficiency and bisphosphonate therapy on bone tissue properties using an ovine model of osteoporosis. Skeletally mature animals (4+ years) were divided into an ovariectomy group (ovx, n=20) and a non treatment control group (control, n=20). A zoledronic acid treated group was also included in which animals were estrogen deficient for 20 months prior to receiving treatment (Zol, n=4). Half of the control and ovx groups were euthanized 12 or 31 months post-operatively and all Zol animals were euthanised at 31 months. Individual trabeculae were removed from the proximal femur and were analysed at specific locations across the width of the trabeculae. The mineral content was measured using quantitative backscatter electron imaging and the modulus was measured using nanoindentation. The spatial distribution of tissue modulus and mineral content in bone from ovariectomised animals was similar to control. However, ovariectomy significantly reduced the overall mineral content and tissue modulus relative to the control group after 12 months. Interestingly, significant differences were not maintained 31 months post-OVX. Treatment with zoledronic acid increased the mineral content and tissue modulus relative to both the ovariectomised and control groups. Zoledronic acid was also found to alter the mineral and modulus gradients normally associated with healthy bone tissue. The current study provides evidence that both estrogen deficiency and zoledronic acid therapy significantly alter mineral content and the mechanical properties of trabecular tissue.

The utilization of thin film transistor liquid crystal display waste glass as a pozzolanic material

This investigation elucidates the pozzolanic behavior of waste glass blended cement (WGBC) paste used in thin film transistor liquid crystal displays (TFT-LCD). X-ray diffraction (XRD) results demonstrate that the TFT-LCD waste glass was entirely non-crystalline. The leaching concentrations of the clay and TFT-LCD waste glass all met the current regulatory thresholds of the Taiwan EPA. The pozzolanic strength activity indices of TFT-LCD waste glass at 28 days and 56 days were 89% and 92%, respectively. Accordingly, this material can be regarded as a good pozzolanic material. The amount of TFT-LCD waste glass that is mixed into WGBC pastes affects the strength of the pastes. The strength of the paste clearly declined as the amount of TFT-LCD waste glass increased. XRD patterns indicated that the major difference was the presence of hydrates of calcium silicate (CSH, 2 theta=32.1 degrees), aluminate and aluminosilicate, which was present in WGBC pastes. Portland cement may have increased the alkalinity of the solution and induced the decomposition of the glass phase network. WGBC pastes that contained 40% TFT-LCD waste glass have markedly lower gel/space ratios and exhibit less degree of hydration than ordinary Portland cement (OPC) pastes. The most satisfactory characteristics of the strength were observed when the mixing ratio of the TFT-LCD waste glass was 10%.

CT grading of otosclerosis

BACKGROUND AND PURPOSE

The CT grading system for otosclerosis was proposed by Symons and Fanning in 2005. The purpose of this study was to determine if this CT grading system has high interobserver and intraobserver agreement.

MATERIALS AND METHODS

All 997 petrous bone CTs performed between December 2000 and September 2007 were reviewed. A total of 81 subjects had CT evidence of otosclerosis on at least 1 side; 68 (84%) had bilateral disease. Because otosclerosis was clinically suspected in both ears of all 81 subjects even if CT evidence was only unilateral, both petrous bones (162 in total) were included. Two blinded neuroradiologists independently graded disease severity using the Symons/Fanning grading system: grade 1, solely fenestral; grade 2, patchy localized cochlear disease (with or without fenestral involvement) to either the basal cochlear turn (grade 2A), or the middle/apical turns (grade 2B), or both the basal turn and the middle/apical turns (grade 2C); and grade 3, diffuse confluent cochlear involvement (with or without fenestral involvement). One reviewer repeat-graded the petrous bone CTs to determine intraobserver agreement with a 7-month intervening delay to mitigate recall bias.

RESULTS

There were 154 agreements (95%) comparing the first grading of reviewer 1 with that of reviewer 2 (kappa = 0.93). When the repeat 7-month delayed grading of reviewer 1 was compared with that of reviewer 2, there were 151 (93%) agreements (kappa = 0.90). Therefore, mean interobserver agreement was excellent (mean kappa = 0.92). There were 155 agreements (96%) comparing the original grading of reviewer 1 with the delayed grading (kappa = 0.94), demonstrating excellent intraobserver agreement.

CONCLUSIONS

A recently published CT grading for otosclerosis on the basis of location of involvement yielded excellent interobserver and intraobserver agreement.

Biomechanical properties across trabeculae from the proximal femur of normal and ovariectomised sheep

The elastic behaviour of trabecular bone is a function not only of bone volume and architecture, but also of tissue material properties. Variation in tissue modulus can have a substantial effect on the biomechanical properties of trabecular bone. However, the nature of tissue property variation within a single trabecula is poorly understood. This study uses nanoindentation to determine the mechanical properties of bone tissue in individual trabeculae. Using an ovariectomised ovine model, the modulus and hardness distribution across trabeculae were measured. In both normal and ovariectomised bone, the modulus and hardness were found to increase towards the core of the trabeculae. Across the width of the trabeculae, the modulus was significantly less in the ovariectomised bone than in the control bone. However, in contrast to this hardness was found not to differ significantly between the two groups. This study provides valuable information on the variation of mechanical material properties in healthy and diseased trabecular bone tissue. The results of the current study will be useful in finite element modelling where more accurate values of trabecular bone modulus will enable the prediction of the macroscale behaviour of trabecular bone.

Observation of strong electron dephasing in highly disordered Cu93Ge4Au3 thin films

We report the observation of strong electron dephasing in a series of disordered Cu93Ge4Au3 thin films. A very short electron dephasing time possessing very weak temperature dependence around 6 K, followed by an upturn with further decrease in temperature below 4 K, is found. The upturn is progressively more pronounced in more disordered samples. Moreover, a lnT-dependent, but high-magnetic-field-insensitive, resistance rise persisting from above 10 K down to 30 mK is observed in the films. These results suggest a nonmagnetic dephasing process which is stronger than any known mechanism and may originate from the coupling of conduction electrons to dynamic defects.