Safe and adequate placement of nasogastric tubes in the presence of a cuffed tracheostomy tube

This case report and review of the literature aims to highlight the importance of the use of a chest radiograph to check the placement of nasogastric tubes after insertion in an awake patient with an inflated cuffed tracheostomy tube regardless of an acidic pH test.

Qualifying the use of RIS data for patient dose by comparison with DICOM header data

A system was developed in 2008 to calculate patient doses using Radiology Information System (RIS) data and presents these data as a patient dose audit. One of the issues with this system was the quality of user-entered data. It has been shown that Digital Imaging and Communication in Medicine (DICOM) header data can be used to perform dose audits with a high level of data accuracy. This study aims to show that using RIS data for dose audits is not only a viable alternative to using DICOM header data, but that it has advantages. A new system was developed to pull header data from DICOM images easily and was installed on a workstation within a hospital department. Data were recovered for a common set of examinations using both RIS and DICOM header data. The data were compared on a result-by-result basis to check for consistency of common fields between RIS and DICOM, as well as assessing the value of data fields uncommon to both systems. The study shows that whilst RIS is not as accurate as DICOM, it does provide enough accurate data and that it has other advantages over using a DICOM approach. These results suggest that a 'best of both worlds' may be achievable using Modality Performed Procedure Step (MPPS).

Steroids and recurrent IgA nephropathy after kidney transplantation

We studied the impact of steroid use on kidney graft loss due to recurrent IgA nephropathy (IgAN). We used data from the Australia and New Zealand Dialysis and Transplant Registry (ANZDATA) to conduct a survival analysis of adult recipients of a first kidney transplant for IgAN who received a graft between 1988 and 2007. Predictors of graft loss due to recurrent IgAN were analyzed in a competing risk survival analysis with steroid use modeled as a time-varying covariate. Fifteen hundred twenty-one recipients with kidney failure due to biopsy-proven IgAN received a first kidney transplant during the study period. Four hundred and twenty-eight recipients experienced graft loss, of which 54 losses (12.6%) were attributed to recurrent IgAN. The overall 10-year cumulative incidence of graft loss from recurrent IgAN was 4.3% (95% CI 3.1-5.8). Prevalence of steroid use was 92% at baseline, 84% at 1 year and 64% at 5 years. After adjusting for age, sex, HLA mismatch, dialysis duration and transplant era, steroid use was strongly associated with a reduced risk of recurrence (subhazard ratio 0.50, 95% CI 0.30-0.84). These results suggest that the risk of graft loss from recurrent disease should be considered when tailoring immunosuppression for patients with IgAN.

Assessment of diabetic macrovascular complications: a prediabetes model

Prediabetes is a condition that requires early intervention against diabetic macrovascular complications. This study aims to assess whether or not the likelihood of diabetes macrovascular complications occurring in prediabetes can be better estimated by a model combining a set of conventional and emerging biomarkers, with a view to improving cardiovascular disease (CVD) screening in individuals with elevated blood glucose levels associated with prediabetes. A total of 71 participants (female/male: 32/39) were divided into two groups - the prediabetic group (preDM: n=34) and the diabetic with cardiovascular complications group (DM+CVD: n=37). Blood glucose level (BGL), blood pressure (BP), total cholesterol (TC), high-density lipoprotein (HDL) and TC:HDL ratio, erythrocyte oxidative stress (as determined by reduced glutathione [GSH], malondialdehyde and methaemoglobin levels) and vascular events (D-dimer, homocysteine and whole blood viscosity) were measured. Statistical analysis was by binomial logistic regression modelling with forward likelihood ratio step procedures. A combination of BGL, BP, erythrocyte GSH and TC gave the best group identifications, with 28/34 (82.4%) and 29/37 (78.4%) members correctly identified in the preDM and DM + CVD groups, respectively. Six of the 34 (17.6%) prediabetes individuals were logistically identified as having diabetic macrovascular complications, but clinically did not qualify for CVD intervention under current screening models. The authors propose that a combination of BGL, BP, erythrocyte GSH and TC can provide a clinically acceptable standard for identifying CVD risk in individuals with prediabetes. This model provides a tool for early identification and targeted intervention in individuals with subclinical diabetes who are at risk of CVD.

Effectiveness and safety of a structured swimming program in previously sedentary women during pregnancy

OBJECTIVE

To determine whether undertaking a swimming program in sedentary women during pregnancy would improve maternal fitness without adverse fetal consequences.

METHODS

Prospective observational investigation of healthy sedentary pregnant women participating in a monitored swimming program.

RESULTS

Twenty-three women attended swimming sessions from 16 to 28 weeks of gestation resulting in increasing distances swum and improved aerobic fitness as measured by physical work capacity (PWC170) (p = 0.003). Resting maternal heart rate decreased (p = 0.041) and resting systolic (p = 0.092) and diastolic (p = 0.971) blood pressures remained unchanged over gestation. The mean fetal heart rates decreased with advancing gestational age (p = 0.001), consistent with normal physiology. Non-stress tests and umbilical artery systolic/diastolic ratios were similar before and after swimming sessions, providing evidence that fetal well-being was unchanged.

CONCLUSIONS

A structured swimming program in sedentary pregnant women increases maternal fitness without any alteration in maternal and fetal well-being.

Recognition of emotion from facial expression following traumatic brain injury

PRIMARY OBJECTIVE

To assess three domains of emotion recognition in people with traumatic brain injury (TBI).

RESEARCH DESIGN

A between group comparison.

PROCEDURES

Twenty-four participants with severe TBI and 15 matched participants without brain damage were asked to label and match facial expressions with and without context. The participants with TBI were also interviewed regarding changes in subjective experience of emotion.

MAIN OUTCOMES AND RESULTS

Participants with TBI were found to be significantly impaired on expression labelling and matching, but experienced some improvement when provided with context. Negative emotions were particularly affected. Affective semantic knowledge and face perception appeared to be relatively intact in this group. The majority of participants with TBI reported some change in the post-injury experience of everyday emotion, although the pattern of changes differed greatly between individuals. Reduced subjective experience, especially of sadness and fear, was associated with poor emotion matching but not emotion labelling.

Material Orientation Artifact Studies in Magnetic Resonance Imaging

With the increased interest of MRI guided interventional procedures in modern medical treatments, image distortion and artifact formation based on material selection and orientation within the MRI scanner are central concerns for precise object localization. The goal of this study was to illustrate the artifact behavior of materials with various magnetic susceptibilities and radio frequency conductivity values corresponding to object orientation relative to the primary magnetic field. To test the effects of orientation on image distortion and image artifacts, 0.125 inch cylindrical test samples of various materials were imaged using a clinical Siemens 3 Tesla MR scanner. Modern medical instrumentation and surgical utensils are typically made from highly paramagnetic materials (e.g., titanium, nitinol, or stainless steel) which also have high RF conductivities. The combination of these two material properties cause both primary magnetic field (B0) and RF field (B1) inhomogeneities which lead to local image distortions. A change in the local magnetic field induces errors within the slice selection gradient, as the precessional frequency of the proton nuclei in the desired region of interest will not correspond to the exact spatial location on the object and will excite a broader region due to the RF conductivity of the material. Conversely to more traditional surgical materials, diamagnetic materials (e.g., bismuth, pyrolytic carbon, water, most plastics) are free from the susceptibility artifacts due to B0 inhomogeneities and thus offer a level of MR compatibility that traditional materials cannot. A specific testing phantom was built to fit a clinical wrist coil. The phantom consisted of an aqueous solution of gadolinium and copper sulfate to increase image contrast and a rotatable turret post for sample positioning. The particular materials studied were chosen to demonstrate the wide variation in both magnetic susceptibility values and RF conductivities (e.g., 6A1-4V titanium, 316L stainless steel, carbon fiber, 6061 T6 aluminum, brass, copper, beryllium copper). ImageJ software measured the overall pixel area and major dimension of each MR image artifact at 0, 45, and 90 degree orientations of each test sample relative to B0. The results of the measurements indicated measurable increases in signal are of the paramagnetic and highly conductive test specimens orientated orthogonal to the primary magnetic field. For instance, two common medical grade materials such as 316L stainless steel and 6Al-4V titanium resulted in artifact area increases of 770±10% and 234±10%, respectively, relative to the actual cross sectional area of the sample. Conversely, the more diamagnetic materials, carbon fiber and beryllium copper demonstrated increased artifact areas of 8±10% and 12±10%, respectively. Errors in artifact area percentage growth measurement are primarily attributed to manual image segmentation and variation in coil positioning within the MRI bore. The results indicate that MR image artifact size and object distortion characteristics can be influenced by both material selection and object orientation relative to the primary magnetic field. In the interest of accurate navigation of image guided equipment and devices, interventional devices should be tested for image distortion in multiple orientations. This work is supported by MIMTeC, a National Science Foundation Industry University Collaborative Research Center and by NIH Grant P30 NS057091.

Use of Colloidal Graphite Coating to Reduce Magnetic Resonance Imaging Artifacts Caused by Metallic Objects

Magnetic susceptibility mismatch, between human tissue and a foreign metallic object, is one of several factors responsible for image distortions in magnetic resonance imaging (MRI). Combining diamagnetic materials such as bismuth or carbon with paramagnetic materials such as nitinol or titanium can reduce the mismatch in bulk susceptibility of a foreign object and the surrounding tissue. Muller-Bierl et al. have succeeded in reducing MRI field distortion by coating titanium wire with bismuth. Wilson et al. used a pyrolytic graphite mouth shim to improve brain functional MRI performance. Conolly et al. have successfully used pyrolytic graphite in foam to reduce image artifacts at air-tissue interfaces. In this study, it was hypothesized that coating a metallic object with carbon particles suspended in a polymer can reduce the size of image artifacts. Four 6Al-4V titanium discs (2.3mm×9.5mm∅) were encapsulated in an epoxy-graphite mixture. Mixtures of graphite and epoxy were poured around the titanium discs in molds and allowed to cure. A specimen of titanium was encapsulated in plain epoxy to serve as the control sample. Polycrystalline graphite was mixed at mass ratios of 1:2 and 1:1 to epoxy for two of the samples. Pyrolytic graphite flakes were mixed at a 1:2 mass ratio to epoxy. The sample discs were placed in an aqueous solution of copper sulfate and gadolinium contrast agent inside a wrist imaging coil at the isocenter of a 3 Tesla MRI machine; disc axes were perpendicular to the B0 direction. A T2-weighted gradient echo MRI image was taken in the coronal plane. Echo time, relaxation time, flip angle, and phase encode direction set to 71 ms, 3430 ms, 80 degrees, and right to left respectively. The control sample produced an arrowhead artifact sweeping in the same direction as the static magnetic field vector, B0. The two samples containing powdered polycrystalline graphite produced arrowhead shaped artifacts. The direction of image distortion, however, was opposite from that of the control sample. The change in direction of the image artifact is attributed to the change in bulk magnetic susceptibility of the sample from paramagnetic behavior of titanium encapsulated in plain epoxy to a diamagnetic behavior from the added carbon powder. The titanium sample encapsulated in the pyrolytic graphite-epoxy mixture produced an artifact with irregular outline and no discernable directional bias relative to B0. The hypothesized cause for this difference in artifact shape between the polycrystalline and pyrolytic graphite samples is an increase in air bubble entrapment due to the planar structure of the pyrolytic graphite flakes during the epoxy mixing process. Further study is underway to find a specific carbon-polymer mass ratio and coating thickness that will reduce MR image artifacts that would otherwise appear due to the presence of a metallic object in the MRI region of interest. This work is supported by MIMTeC, a National Science Foundation Industry University Collaborative Research Center and by NIH Grant P30NS057091.

First Report of Brown Ring Patch Caused by Waitea circinata var. circinata on Poa annua in Virginia

Brown ring patch was first described as a disease of cool-season turfgrass on creeping bentgrass (Agrostis palustris) (4) in Japan and later reported in California on annual bluegrass (Poa annua) (2). Brown ring patch symptoms were observed beginning in December 2007 through spring 2008 on 6 of 18 putting greens on a golf course in Reston, VA. Symptoms included yellow rings and patches of blighted turfgrass on the mixed stands of creeping bentgrass (A. palustris) and primarily annual bluegrass (Poa annua). Chlorosis and blight occurred predominantly on P. annua. A turfgrass sample was received from a consultant in April 2008, and disease severity on affected greens was estimated to be 40%. After incubating for 2 days in a moist chamber, Rhizoctonia-like aerial mycelia were observed. The pathogen was isolated on water agar and potato dextrose agar amended with thiophanate-methyl (100 mg/L), rifampicin (100 mg/L), and ampicillin (500 mg/L) from P. annua plants that had been surface sterilized with 70% ethanol for 15 s. Colony and sclerotia morphology were consistent with Waitea circinata var. circinata as previously described (2,4). Hyphae were stained with aniline blue and multiple nuclei were observed per cell. The teleomorph was not observed on plant material or in culture. Amplified fragments of rDNA including internal transcribed spacers from the isolate were amplified in three bacterial clones and sequenced bidirectionally (GenBank Accession Nos. FJ154894, FJ154895, and FJ154896) using primers ITS1/ITS4 (2,4). The consensus sequences matched, with 99% homology and 99% sequence overlap, isolate TRGC1.1 of W. circinata var. circinata (GenBank Accession No. DQ900586) (2). Annual bluegrass was not available for use in performing Koch's postulates, but previous studies have shown that W. circinata var. circinata is pathogenic to roughstalk bluegrass (P. trivialis) (1,3). Pots of P. trivialis cv. Cypress that were 1 week postemergence were inoculated with seven wheat grains that had been autoclaved and then infested with the isolate. Plants were incubated at 25°C in a sealed plastic bag with a moist paper towel on the bottom. Hyphae grew from the grains and colonized the grass. Individual plants began to turn chlorotic within 3 days, and more than 80% of the turf in pots was dead after 1 week. Control pots were inoculated with autoclaved wheat seed and showed no disease symptoms after 1 week. Inoculations were repeated twice more with the same results. W. circinata var. circinata was reisolated from affected plants in all replications of the test. To our knowledge, this is the first report of brown ring patch in Virginia. Additional research is needed to assess the prevalence and importance of this disease on golf course putting greens in Virginia. References: (1) C. M. Chen et al. Plant Dis. 91:1687, 2007. (2) K. A. de la Cerda et al. Plant Dis. 91:791, 2007. (3) N. Flor et al. Plant Dis. 92:1586, 2008. (4) T. Toda et al. Plant Dis. 89:536, 2005.

Brachiopod punctae: a complexity in shell biomineralisation

Perforations ("punctae") are one of the most characteristic morphological shell features in calcite brachiopods. The significance of punctae is that they represent discontinuities in shell biomineralisation and thus add a level of complexity that must be accounted for in any model of brachiopod shell formation. A significant hindrance to understanding punctae growth and formation is the absence of sufficient information on volume, size and density. Here, we use synchrotron-radiation X-ray tomographic microscopy (SRXTM) to obtain three-dimensional information about punctae of five species of calcite brachiopods. X-ray tomography shows that punctae morphology is species-specific and reveals previously unknown levels of complexity for each species. This information is combined with previous data on morphology to discuss the function and growth of punctae. Overall the present study demonstrates the need to increase our understanding of discontinuities and the role of cell biology in the context of biomineralisation.