The effect of hierarchical micro/nanosurface titanium implant on osseointegration in ovariectomized sheep

Hydrofluoric etching and anodized hierarchical micro/nanotextured surface titanium implant was placed in mandibles of ovariectomized sheep for 12 weeks, and it showed improved osseointegration by resonance frequency analysis (RFA), microcomputed tomography (micro-CT) evaluation, histomorphometry, and biomechanical test.

INTRODUCTION

This study aimed to investigate the effects of micro/nanotextured titanium implant on osseointegration in ovariectomized (OVX) sheep.

METHODS

The hierarchical micro/nanotextured surface of titanium implant was fabricated by acid in 0.5% (w/v) hydrofluoric (HF) and anodized in HF acid electrolytes with a DC power of 20 V, and the machined surface implants with no treatment served as control group. The implants were placed in mandibles of OVX sheep, respectively. Twelve weeks after implantation, RFA, microcomputed tomography, histomorphometry, and biomechanical tests were applied to detect the osseointegration of the two groups.

RESULTS

The implant stability quotient (ISQ) values, the maximum pull-out forces, and the bone-implant contact (BIC) were 65.5 ± 6.3, 490.6 ± 72.7 N, and 58.31 ± 5.79% in the micro/nanogroup and 58.3 ± 8.9, 394.5 ± 54.5 N, and 46.85 ± 5.04% in the control group, respectively. There was no significant difference between the two groups in ISQ values (p > 0.05), but in the micro/nanogroup, the maximal pull-out force and the BIC were increased significantly (p < 0.05 or p < 0.01). Micro-CT analysis showed that the bone volume ratio and the trabecular number increased significantly (p < 0.01), and the trabecular separation decreased significantly (p < 0.05) in the micro/nanogroup.

CONCLUSION

Implant modification by HF acid etching and anodization to form a hierarchical micro/nanotextured surface could improve titanium implant osseointegration in OVX sheep 12 weeks after implantation.

Part 5. Public health and air pollution in Asia (PAPA): a combined analysis of four studies of air pollution and mortality

BACKGROUND

In recent years, Asia has experienced rapid economic growth and a deteriorating environment caused by the increasing use of fossil fuels. Although the deleterious effects of air pollution from fossil-fuel combustion have been demonstrated in many Western nations, few comparable studies have been conducted in Asia. Time-series studies of daily mortality in Asian cities can contribute important new information to the existing body of knowledge about air pollution and health. Not only can these studies verify important health effects of air pollution in local regions in Asia, they can also help determine the relevance of existing air pollution studies to mortality and morbidity for policymaking and environmental controls. In addition, the studies can help identify factors that might modify associations between air pollution and health effects in various populations and environmental conditions. Collaborative multicity studies in Asia-especially when designed, conducted, and analyzed using a common protocol-will provide more robust air pollution effect estimates for the region as well as relevant, supportable estimates of local adverse health effects needed by environmental and public-health policymakers.

SPECIFIC OBJECTIVES

The Public Health and Air Pollution in Asia (PAPA*) project, sponsored by the Health Effects Institute, consisted of four studies designed to assess the effects of air pollution on mortality in four large Asian cities, namely Bangkok, in Thailand, and Hong Kong, Shanghai, and Wuhan, in China. In the PAPA project, a Common Protocol was developed based on methods developed and tested in NMMAPS, APHEA, and time-series studies in the literature to help ensure that the four studies could be compared with each other and with previous studies by following an established protocol. The Common Protocol (found at the end of this volume) is a set of prescriptive instructions developed for the studies and used by the investigators in each city. It is flexible enough to allow for adjustments in methods to optimize the fit of health-effects models to each city's data set. It provides the basis for generating reproducible results in each city and for meta-estimates from combined data. By establishing a common methodology, factors that might influence the differences in results from previous studies can more easily be explored. Administrative support was provided to ensure that the highest quality data were used in the analysis. It is anticipated that the PAPA results will contribute to the international scientific discussion of how to conduct and interpret time-series studies of air pollution and will stimulate the development of high-quality routine systems for recording daily deaths and hospital admissions for time-series analysis.

METHODS

Mortality data were retrieved from routine databases with underlying causes of death coded using the World Health Organization (WHO) International Classification of Diseases, 9th revision or 10th revision (ICD-9, ICD-10). Air quality measurements included nitrogen dioxide (NO2), sulfur dioxide (SO2), particulate matter with aerodynamic diameter < or = 10 microm (PM10), and ozone (O3) and were obtained from several fixed-site air monitoring stations that were located throughout the metropolitan areas of the four cities and that met the standards of procedures for quality assurance and quality control carried out by local government units in each city. Using the Common Protocol, an optimized core model was established for each city to assess the effects of each of the four air pollutants on daily mortality using generalized linear modeling with adjustments for time trend, seasonality, and other time-varying covariates by means of a natural-spline smoothing function. The models were adjusted to suit local situations by correcting for influenza activity, autocorrelation, and special weather conditions. Researchers in Hong Kong, for example, used influenza activity based on frequency of respiratory mortality; researchers in Hong Kong and Shanghai used autoregressive terms for daily outcomes at lag days; and researchers in Wuhan used additional smoothing for periods with extreme weather conditions.

RESULTS AND DISCUSSION

For mortality due to all natural (nonaccidental) causes at all ages, the effects of air pollutants per 10-microg/m3 increase in concentration was found to be higher in Bangkok than in the three Chinese cities, with the exception of the effect of NO2 in Wuhan. The magnitude of the effects for cardiovascular and respiratory mortality were generally higher than for all natural mortality at all ages. In addition, the effects associated with PM10 and O3 in all natural, cardiovascular; and respiratory mortality were found to be higher in Bangkok than in the three Chinese cities. The explanation for these three findings might be related to consistently higher daily mean temperatures in Bangkok, variations in average time spent outdoors by the susceptible populations, and the fact that less air conditioning is available and used in Bangkok than in the other cities. However, when pollutant concentrations were incorporated into the excess risk estimates through the use of interquartile range (IQR), the excess risk was more comparable across the four cities. We found that the increases in effects among older age groups were greater in Bangkok than in the other three cities. After excluding data on extremely high concentrations of PM10 in Bangkok, the effect estimate associated with PM10 concentrations decreased in Bangkok (suggesting a convex relationship between risk and PM10, where risk levels off at high concentrations) instead of increasing, as it did in the other cities. This leveling off of effect estimates at high concentrations might be related to differences in vulnerability and exposure of the population to air pollution as well as to the sources of the air pollutant. IMPLICATIONS OF THE STUDY: The PAPA project is the first coordinated Asian multicity air pollution study ever published; this signifies the beginning of an era of cooperation and collaboration in Asia, with the development of a common protocol for coordination, data management, and analysis. The results of the study demonstrated that air pollution in Asia is a significant public health burden, especially given the high concentrations of pollutants and high-density populations in major cities. When compared with the effect estimates reported in the research literature of North America and Western Europe, the study's effect estimates for PM10 were generally similar and the effect estimates for gaseous pollutants were relatively higher. In Bangkok, however, a tropical city where total exposures to outdoor pollution might be higher than in most other cities, the observed effects were greater than those reported in the previous (i.e., Western) studies. In general, the results suggested that, even though social and environmental conditions across Asia might vary, it is still generally appropriate to apply to Asia the effect estimates for other health outcomes from previous studies in the West. The results also strongly support the adoption of the global air quality guidelines recently announced by WHO.

Selection of the distraction implant length with improved biomechanical properties by three-dimensional finite element analysis

In this study, the distraction length of distraction implant was set as input variable which ranged from 2 to 10 mm. The effect of distraction length on the maximum Von Mises stress in the jaw bones and the implant were evaluated by a finite element method. The results showed that under axial load, the maximum equivalent stresses in cortical bone, cancellous bone, and distraction screw decreased by 5·8%, 8·6%, and 11·0%, respectively, with the changing of distraction length, and under buccolingual load those decreased by 0·3%, 18·0%, and 13·0%, respectively. The data indicate that cancellous bone is more sensitive to distraction length than the cortical bone. Under both loads, the central distraction screw was subjected to the stress concentration and more easily damaged by buccolingual force than by axial force. Distraction implant with distraction length exceeding 8 mm showed relatively better biomechanical behaviour.

Further evaluation of 11C-PD153035 as a molecular imaging probe for the assessment of the epidermal growth factor receptor status in non-small cell lung cancer patients

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Background: Epidermal growth factor receptor (EGFR) plays a key role in tumorgenosis and is therefore an important target for new therapeutic and prognostic strategies. Our pilot study has demonstrated that 11C-PD153035, a highly EGFR selective tracer for positron emission tomography (PET), accumulated in tumor mass of non-small cell lung cancer (NSCLC) and the tracer uptake correlated with EGFR expression. Here, we further evaluate correlation between the intensity of 11C-PD153035 uptake and EGFR protein expression level and gene mutation. Methods: Fourteen patients (45–71y, mean 59.2±9.2 y, Male: Female = 8:6, squamous carcinoma: adenocarcinoma = 9:5) with pathologically proved NSCLC were examined with PET using 11C-PD153035 one week before surgery. Radioactivity concentrations, derived from regions of interest (ROI), were analyzed mathematically to maximum standardized uptake value (SUVmax). The EGFR protein expression of surgical specimen was utilized by immunohistochemistry (IHC) with a three-tier system intensity scored and Western Blot assay. The EGFR genetic alterations in exon 19 and 21 were examined by direct sequencing of polymerase chain reaction (PCR) products. Results: 11C-PD153035 uptake was observed in 9 out of 14 NSCLC patients (mean SUV 3.94±1.06, range 0.8–5.9) and the biodistribution study further demonstrated accumulation of radioactivity in the tumor mass. The SUVmax of 11C-PD153035 molecular images did not correlate with tumor size and injection dose of the tracer. A closely correlation between SUVmax and EGFR protein expression as determined by IHC (r = 0.84, p = 0.005) was observed but not with the protein expression level of Western Blot analysis (r = 0.442, p = 0.114), as well as EGFR exon 19 (r = -0.078, p = 0.790) or exon 21 (r = 0.118, p = 0.689) gene mutation. With ROC analysis according to IHC intensity, the cut-off value of SUVmax was 2.45. Conclusions: PET with 11C-PD153035 might therefore be used to visualize EGFR pattern on tumor in NSCLC patients and for individualized planning of therapeutic strategies with EGFR targeted drugs, especially small-molecule TKIs (gefitinib and erlotinib) which targeting the intracellular EGFR tyrosine kinase domain as PD153035.

No significant financial relationships to disclose.

The role of whole body 18F-FDG PET/CT scan in patients with carcinoma of unknown primary

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Background: Carcinoma of unknown primary (CUP) is a heterogeneous group of tumors and usually follows an aggressive biological and clinical behavior. Difficult challenges in oncology which the identification of the primary tumor and a complete disease staging could offer a more rational and efficient treatment in order to improve the survival time. Our aim was to evaluate the role of 18F-FDG PET/CT scan with two aspects: detection of the primary site, and estimation of tumor biological behavior which essential for the development of new, individual and targeted effective therapies. Methods: One hundred and seventeen patients presenting with histologically confirmed metastatic carcinoma (76 lymph nodes, 41 visceral biopsy proven) of unknown primary site were included in this retrospective study. The evaluations as follows had not revealed a primary site: detailed medical history, full physical and laboratory examinations, and diagnostic imaging methods. All patients underwent PET/CT. Results: In 42 (35.90%) patients, a primary tumor site which was confirmed by follow-up or surgery was showed by PET/CT. In 15 (12.82%) patients, the primary tumor site was suggested by PET/CT but not confirmed. In 60 (51.28%) patients, the primary tumor site was not localized modifying the stage of disease. In the other 17 (14.53%) patients, PET/CT scan identified further unexpected metastases. Overall, the following oncological treatment was influenced by the PET/CT scan, in a total of 38 (32.47%) patients. Between the adenocarcinoma and squamous cell carcinoma groups, no significant difference in SUVmax was found ( t=1.191, p = 0.244). A significantly higher SUVmax was found among patients with poorly or undifferentiated carcinoma compared with patients with well to moderately ( t=4.013, p<0.01) differentiation; In 42 patients with a confirmed primary tumor site, the SUVmax of Metastatic tumours have a closely relationship correlate with those of primary tumours, ( r=0.738, p<0.01). Furthermore, a significantly higher SUVmax was found among metastases compared with primary tumors ( t=3.470, p<0.01). Conclusions: Our data strongly support 18F-FDG PET/ CT imagings not only provide new insights in the diagnosis and staging of patients with CUP, but also evaluate biologic characters of tissue. 1

No significant financial relationships to disclose.

A comparative study of the skeletal morphology of the temporo-mandibular joint of children and adults

BACKGROUND

The skeletal morphology of the temporo-mandibular joint (TMJ) is constantly remodeled.

AIMS AND OBJECTIVES

A comparative study was undertaken to determine and characterize the differences in the skeletal morphology of TMJ of children and adults.

MATERIALS AND METHODS

The study was conducted on 30 children cadavers and 30 adult volunteers. Parameters that could reflect TMJ skeletal morphology were measured with a new technology combining helical computed tomography (CT) scan with multi-planar reformation (MPR) imaging.

RESULTS

Significant differences between children cadavers and adults were found in the following parameters (P<0.05): Condylar axis inclination, smallest area of condylar neck/largest area of condylar process, inclination of anterior slope in inner, middle, and outer one-third of condyle, anteroposterior/mediolateral dimension of condyle, length of anterior slope/posterior slope in inner and middle one-third of condyle, anteroposterior dimension of condyle/glenoid fossa, mediolateral dimension of condyle/glenoid fossa, inclination of anterior slope of glenoid fossa, depth of glenoid fossa, and anteroposterior/mediolateral dimension of glenoid fossa.

CONCLUSION

There are significant differences of TMJ skeletal morphology between children and adults.