Macrophages and nitric oxide: A deadly combination

In the late 1980s, Carl Nathan and colleagues pinpointed nitric oxide (NO) as a molecule that macrophages use to kill tumor cells. This discovery helped verify the role of radicals as signaling molecules in the immune system

A robust digital method for film contrast correction in subtraction radiography

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66366/1/j.1600-0765.1986.tb01484.x.pd

Mathieu De Costa: Missing

Public history poster on Mathieu Da Costa by students Anmol Scolia, HarminderMall, Maria Domdom, Diana Lewars, and Wayne Ruttimann.https://source.sheridancollege.ca/swfhass_black_poster/1009/thumbnail.jp

Effect of Periodontal Therapy on Alveolar Bone as Measured by Subtraction Radiography

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141973/1/jper0633.pd

A Pyramid Approach to Subpixel Registration Based on Intensity

We present an automatic sub-pixel registration algorithm that minimizes the mean square difference of intensities between a reference and a test data set, which can be either tri-dimensional (3-D) volumes or bi-dimensional (2-D) images. It uses spline processing, is based on a coarse-to-fine strategy (pyramid approach), and performs minimization according to a new variation of the iterative Marquardt-Levenberg algorithm for non-linear least-square optimization (MLA). The geometric deformation model is a global 3-D affine transformation, which one may restrict to the case of rigid-body motion (isometric scale, rotation and translation). It may also include a parameter to adjust for image contrast differences. We obtain excellent results for the registration of intra-modality Positron Emission Tomography (PET) and functional Magnetic Resonance Imaging (fMRI) data. We conclude that the multi-resolution refinement strategy is more robust than a comparable single-scale method, being less likely to get trapped into a false local optimum. In addition, it is also faster

Detection of ATP by "in line” 31P magnetic resonance spectroscopy during oxygenated hypothermic pulsatile perfusion of pigs' kidneys

Object: To demonstrate that adenosine triphosphate (ATP), which provides a valuable biomarker for kidney viability in the context of donation after cardiac death (DCD) transplantation, can be detected by means of 31P magnetic resonance spectroscopy (MRS) if kidneys are perfused with oxygenated hypothermic pulsatile perfusion (O2+HPP). Materials and methods: Porcine kidney perfusion was carried out using a home made, MR-compatible HPP-machine. Consequently, kidney perfusion could be performed continuously during magnetic resonance imaging and magnetic resonance spectroscopy recording. 31P MR spectroscopy consisted of 3-dimensional chemical shift imaging (CSI), which allowed for the detection of ATP level in line. 31P CSI was performed at 3tesla in 44min with a nominal voxel size of 6.1cc. Results: 31P CSI enabled the detection of renal ATP when pO2 was equal to 100kPa. With pO2 of 20kPa, only phosphomonoester, inorganic phosphate and nicotinamide adenine dinucleotide could be found. Semi-quantitative analysis showed that ATP level was 1.3mM in normal kidney perfused with pO2 of 100kPa. Conclusions: This combined technology may constitute a new advance in DCD organ diagnostics prior to transplantation, as it allows direct assessment of ATP concentration, which provides a reliable indicator for organ bioenergetics and viability. In this study, kidneys presenting no warm ischemia were tested in order to establish values in normal organs. The test could be easily integrated into the clinical environment and would not generate any additional delay into the transplantation clinical workflo

Fractal analysis of mandibular trabecular bone: optimal tile sizes for the tile counting method

Purpose: This study was performed to determine the optimal tile size for the fractal dimension of the mandibular trabecular bone using a tile counting method. Materials and Methods: Digital intraoral radiographic images were obtained at the mandibular angle, molar, premolar, and incisor regions of 29 human dry mandibles. After preprocessing, the parameters representing morphometric characteristics of the trabecular bone were calculated. The fractal dimensions of the processed images were analyzed in various tile sizes by the tile counting method. Results: The optimal range of tile size was 0.132 mm to 0.396 mm for the fractal dimension using the tile counting method. The sizes were closely related to the morphometric parameters. Conclusion: The fractal dimension of mandibular trabecular bone, as calculated with the tile counting method, can be best characterized with a range of tile sizes from 0.132 to 0.396 mm. ⓒ 2011 by Korean Academy of Oral and Maxillofacial Radiology

Statistical Analysis of Functional MRI Data in the Wavelet Domain

The use of the wavelet transform is explored for the detection of differences between brain functional magnetic resonance images (fMRI's) acquired under two different experimental conditions. The method benefits from the fact that a smooth and spatially localized signal can be represented by a small set of localized wavelet coefficients, while the power of white noise is uniformly spread throughout the wavelet space. Hence, a statistical procedure is developed that uses the imposed decomposition orthogonality to locate wavelet-space partitions with large signal-to-noise ratio (SNR), and subsequently restricts the testing for significant wavelet coefficients to these partitions. This results in a higher SNR and a smaller number of statistical tests, yielding a lower detection threshold compared to spatial-domain testing and, thus, a higher detection sensitivity without increasing type I errors. The multiresolution approach of the wavelet method is particularly suited to applications where the signal bandwidth and/or the characteristics of an imaging modality cannot be well specified. The proposed method was applied to compare two different fMRI acquisition modalities. Differences of the respective useful signal bandwidths could be clearly demonstrated; the estimated signal, due to the smoothness of the wavelet representation, yielded more compact regions of neuroactivity than standard spatial-domain testing

Mortality in very long-stay pediatric intensive care unit patients and incidence of withdrawal of treatment

Background: The mortality for children with prolonged stay in pediatric intensive care units (PICU) is much higher than overall mortality. The incidence of withdrawal or limitation of therapy in this group is unknown. Purpose: To assess mortality and characteristics of children admitted for ≥28 days to our ICU, and to describe the extent to which limitations of care were involved in the terminal phase preceding death. Methods: For the period 2003 to 2005 clinical data were collected retrospectively for children with prolonged stay (defined as ≥28 days) in a medical/surgical PICU of a university children's hospital. Results: In the PICU, 4.4% of the children (116/2,607, equal gender, mean age 29 days) had a prolonged stay. Median (range) stay was 56 (28-546) days. These children accounted for 3% of total admissions and occupied 63% of total admission days. Mortality during admission for this group was fiv