Volumetric rendering techniques: applications for three-dimensional imaging of the hip

Volumetric rendering is a new approach to three-dimensional (3D) imaging that overcomes many of the drawbacks of currently available surface-rendering systems. Its application on the Pixar Imaging System in two cases of acetabular fracture was assessed to illustrate the features of the technique. The fast-computing architecture and large memory of this system allow rapid generation of a series of high-quality 3D images in each plane of rotation (x or spinal axis, z or somersaulting axis) that can be viewed as independent static images or as an animated real-time video loop. Editing to remove the normal contralateral hemipelvis enhances appreciation of acetabular abnormalities. Every pixel of computed tomographic data is preserved, allowing representation of both soft tissue and bone as translucent overlap. The presentation of data also allows detection of subtle abnormalities and features and minimizes the artifact generation common in surface-rendered images.     

Well-defined radiolucent lesion in the maxillary anterior region

A case of nasopalatine duct cyst is described. Such cysts often remain asymptomatic for lengthy periods and may be discovered during routine radiography. The quiescent nature of this cyst underscores the importance of thorough clinical and radiographic examination before the fabrication of a prosthesis, as such cysts may give rise to acute infection, enlargement, and penetration through the overlying mucosa if not removed before denture insertion.     

Defining Risk Thresholds for a 10-Year Probability of Hip Fracture Model That Combines Clinical Risk Factors and Quantitative Ultrasound: Results Using the EPISEM Cohort.

Using a large prospective cohort of over 12,000 women, we determined 2 thresholds (high risk and low risk of hip fracture) to use in a 10-yr hip fracture probability model that we had previously described, a model combining the heel stiffness index measured by quantitative ultrasound (QUS) and a set of easily determined clinical risk factors (CRFs). The model identified a higher percentage of women with fractures as high risk than a previously reported risk score that combined QUS and CRF. In addition, it categorized women in a way that was quite consistent with the categorization that occurred using dual X-ray absorptiometry (DXA) and the World Health Organization (WHO) classification system; the 2 methods identified similar percentages of women with and without fractures in each of their 3 categories, but the 2 identified only in part the same women. Nevertheless, combining our composite probability model with DXA in a case findings strategy will likely further improve the detection of women at high risk of fragility hip fracture. We conclude that the currently proposed model may be of some use as an alternative to the WHO classification criteria for osteoporosis, at least when access to DXA is limited.     

The sheaths ofBrugia microfilariae: Isolation and composition

Burgia malayi andB. pahangi microfilariae were isolated from the blood of infectedMastomys natalensis, and were exsheathed by freezing, thawing and agitation. Pure sheaths were obtained by a filtration procedure. The sheaths were found to contain about 95 mol% of amino acids, with proline, glutamic acid/glutamine, alanine, cysteine/cystine and glycine being the major components, and 5 mol% of carbohydrates, notably (N-acetyl)galactosamine, but no (N-acetyl)glucosamine.     

Use of ektacytometry to determine red cell susceptibility to oxidative stress

To define a more sensitive and reliable method to determine changes in the overall cellular characteristics of erythrocytes after oxidative damage, we used a viscodiffractometric method (ektacytometry) to measure the effect of oxidative stress. Erythrocytes were incubated in the presence of hydrogen peroxide, t-butyl hydroperoxide, or cumene hydroperoxide in phosphate buffer. This treatment resulted in decreased cellular deformability of the intact erythrocytes. In addition, deformability and fragility measurements of the erythrocyte ghost membranes indicated an increased membrane dynamic rigidity and altered-mechanical stability as a consequence of oxidant stress. These changes were observed before the onset of hemolysis. The observed decrease in deformability was accompanied by oxidation of hemoglobin, alterations of membrane proteins, and lipid peroxidation. To continuously measure the time course of the decrease in deformability in intact erythrocytes under oxidative stress, a new ektacytometric method was developed. Erythrocytes were oxidatively challenged within the viscometer at a constant osmolality and shear stress. The change in deformability was monitored and a typical range was defined for erythrocytes from normal individuals. Comparison of erythrocytes from patients with sickle cell disease with those from normal individuals demonstrated a higher susceptibility of sickle red cells toward oxidative stress.     

Addition of L-carnitine to additive solution-suspended red cells stored at 4 degrees C reduces in vitro hemolysis and improves in vivo viability

BACKGROUND: The role of L-carnitine (LC) as the requisite carrier of long-chain fatty acids into mitochondria is well established. Human red cells (RBCs), which lack mitochondria, possess a substantial amount of LC and its esters. In addition, carnitine palmitoyl transferase, an enzyme that catalyzes the reversible transfer of the acyl moiety from acyl-coenzyme A to LC is found in RBCs. It has recently been shown that LC and carnitine palmitoyl transferase play a major role in modulating the pathway for the turnover of membrane phospholipid fatty acids in intact human RBCs, and that LC improved the membrane stability of RBCs subjected to high shear stress. RBC membrane lesions occur during storage at 4 degrees C; this study investigated whether the addition of LC (5 mM) to a standard RBC preservative solution (AS-3) affected cellular integrity with 42 days' storage. STUDY DESIGN AND METHODS: A paired (n = 10) crossover design was used for RBCs stored in AS-3 with and without LC. Both in vitro RBC properties reflective of metabolic and membrane integrity and in vivo measures of cell viability (24-hour percentage of recovery and circulating lifespan) were measured at the end of the storage. In addition, the turnover of membrane phospholipid and long-chain acylcarnitine fatty acids and the carnitine content of control and LC-stored RBCs were measured. RESULTS: It was shown that LC was irreversibly taken up by RBCs during storage, with a fourfold increase at 42 days. Furthermore, as found by the use of radiolabeled palmitate, the stored RBCs were capable of generating long-chain acylcarnitine. The uptake of LC during storage was associated with less hemolysis and higher RBC ATP levels and by a significantly greater in vivo viability for LC-stored RBCs than for control-stored RBCs: a mean 24-hour percentage of recovery of 83.9 +/? 5.0 vs. 80.1 +/? 6.0 percent and a mean lifespan of 96 +/? 11 vs. 86 +/? 14 days, respectively (p < 0.05). CONCLUSION: A beneficial effect of the addition of LC to RBCs stored at 4 degrees C was evident. This effect may be related to both biophysical and metabolic actions on the cell membrane.