Home  About us  Contact
 

Fractional Area (fractional + area)

Distribution by Scientific Domains
Medical Sciences60%

Selected Abstracts

Evidence of a hypermineralised calcified fibrocartilage on the human femoral neck and lesser trochanter

JOURNAL OF ANATOMY, Issue 2 2001
J. E. SHEA
Femoral neck fractures are a major cause of morbidity and mortality in elderly humans. In addition to the age-related loss of cancellous bone, changes to the microstructure and morphology of the metaphyseal cortex may be a contributing factor in osteoporotic hip fractures. Recent investigations have identified a hypermineralised tissue on the neck of the femur and trochanteric region that increases in fractional area with advancing age in both males (Boyce & Bloebaum, 1993) and females (Vajda & Bloebaum, 1999). The aim of this study was to determine if the hypermineralised tissue previously observed on the proximal femur is calcified fibrocartilage. Regional variations in the fractional area of hypermineralised tissue, cortical bone, and porosity of the cortical bone along the neck of the femur and lesser trochanter were also quantified. Comparison of back scattered electron and light microscope images of the same area show that regions of hypermineralised tissue correlate with the regions of calcified fibrocartilage from tendon and capsular insertions. The hypermineralised tissue and calcified fibrocartilage had similar morphological features such as the interdigitations of the calcified fibrocartilage into the bone, lacunar spaces, and distinctly shaped pores adjacent to the 2 tissues. Regions of the neck that did not contain insertions were covered with periosteum. There were no regional differences (P > 0.05) on the superior and inferior femoral neck in terms of the percentage area of hypermineralised calcified fibrocartilage, cortical bone, or cortical bone porosity. The lesser trochanter exhibited regional differences in the fractional area of hypermineralised calcified fibrocartilage (P = 0.007) and cortical bone (P = 0.007) but not porosity of the cortical bone (P > 0.05). The effects of calcified fibrocartilage on femoral neck periosteal expansion, repair, and mechanics are unknown, but may play a role in osteoporotic fractures and intracapsular fracture healing. [source]

Effect of Segregating Impurities on the Grain-Boundary Character Distribution of Magnesium Oxide

JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 12 2009
Francine Papillon
The grain-boundary character distribution (GBCD) of undoped MgO has been measured and compared with samples containing small concentrations of Ca, Sr, Ba, and Y. Auger electron spectroscopy measurements of intergranular fracture surfaces verified that Ca, Ba, and Y segregated anisotropically to grain boundaries (GBs). The segregation of Sr was not detected. The GBCDs of Ca, Ba, and Y doped MgO have more GBs comprised of {100} planes than the undoped material and the fractional area of these planes was highest in the Ca-containing samples. Sr impurities, on the other hand, have no measurable influence on the GBCD. The results demonstrate that GB plane distributions can be controlled through impurity additions. [source]

Biventricular Pacing as Alternative Therapy for Dilated Cardiomyopathy Associated with Congenital Heart Disease

PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 2 2001
EDWIN RODRÍGUEZ-CRUZ
RODRÍGUEZ-CRUZ, E., et al.: Biventricular Pacing as Alternative Therapy for Dilated Cardiomyopathy Associated with Congenital Heart Disease. Biventricular, alternative, and multisite pacing are currently being explored to improve cardiac function among patients with medically refractory, end-stage dilated cardiomyopathies. Although, due to inherent myocardial abnormalities, patients with repaired congenital heart defects may be at a greater risk than others to develop heart failure, often requiring cardiac transplantation. The efficacy of biventricular pacing among these patients is unknown. This report presents a patient with successfully repaired congenital heart disease in infancy who developed a symptomatic dilated cardiomyopathy at 22 years of age. Following biventricular pacing, systemic ventricular function showed a 14% improvement in ventricular dP/dt. One month later, subjective symptoms improved and cardiac ultrasound illustrated a 125% increase in fractional area of change. Exercise stress testing showed a 17% improvement in aerobic work capacity. [source]

Inflammation and angiogenesis in osteoarthritis

ARTHRITIS & RHEUMATISM, Issue 8 2003
L. Haywood
Objective To quantify the relationship between inflammation and angiogenesis in synovial tissue from patients with osteoarthritis (OA). Methods Hematoxylin and eosin staining and histologic grading for inflammation were performed for 104 patients who met the American College of Rheumatology criteria for OA and had undergone total joint replacement or arthroscopy. A purposive sample of synovial specimens obtained from 70 patients was used for further analysis. Vascular endothelium, endothelial cell (EC) proliferating nuclei, macrophages, and vascular endothelial growth factor (VEGF) were detected by immunohistochemical analysis. Angiogenesis (EC proliferation, EC fractional area), macrophage fractional area, and VEGF immunoreactivity were measured using computer-assisted image analysis. Double immunofluorescence histochemical analysis was used to determine the cellular localization of VEGF. Radiographic scores for joint space narrowing and osteophyte formation in the knee were also assessed. Results Synovial tissue samples from 32 (31%) of 104 patients with OA showed severe inflammation; thickened intimal lining and associated lymphoid aggregates were often observed. The EC fractional area, EC proliferation, and VEGF immunoreactivity all increased with increasing histologic inflammation grade and increasing macrophage fractional area. In the synovial intimal lining, VEGF immunoreactivity was localized to macrophages and increased with increasing EC fractional area and angiogenesis. No inflammation or angiogenic indices were significantly correlated with radiographic scores. Conclusion Inflammation and angiogenesis in the synovium are associated with OA. The angiogenic growth factor VEGF generated by the inflamed synovium may promote angiogenesis, thereby contributing to inflammation in OA. [source]

Ultrasonographic characteristics of soft tissue tumours in dogs

AUSTRALIAN VETERINARY JOURNAL, Issue 8 2009
ZHK Loh
Objective To identify and describe the ultrasonographic features of soft tissue tumours in dogs. Procedure Superficial soft tissue tumours of various histological types, including mast cell tumours (MCTs) and soft tissue sarcomas (STSs), were evaluated. Ultrasound was used to visualise internal characteristics of the tumour, including vascularity. Tumours were categorised according to size, shape, margin definition, tissue plane mobility, echogenicity, echotexture, acoustic shadowing or enhancement and vessel distribution. Objective measurements of intratumoural blood flow included velocities and maximal perfused cross-sectional area (fractional area). Logistic regression models incorporating a variety of data were used in an attempt to predict the histopathological type of tumours. Results,, The logistic regression model defined by the parameters echotexture, margin definition and presence of subcapsular vessels was highly predictive of MCTs (> 73%; P = 0.024). Several other trends, including a larger size for STSs and less vascularity for both MCTs and STSs, were observed, but did not reach statistical significance. Conclusion,, This preliminary study has shown the potential diagnostic value of ultrasound in differentiating soft tissue tumours. However, at present, ultrasound cannot replace biopsy and histopathological evaluation for tumour diagnosis. [source]