Unsuccessful long-term outcome after treatment of a vein graft false aneurysm with a polytetrafluoethylene-coated Jostent.

We describe a case in which a stented ulcerated plaque in an old vein graft ruptured to a huge false aneurysm. By the use of a PTFE-coated Jostent, the false aneurysm could be percutaneously closed. However, 6 months later, a new false aneurysm, probably due to focal perforation of the covered Jostent, developed.     

Negative immunoregulatory effects of antidepressants: inhibition of interferon-gamma and stimulation of interleukin-10 secretion.

There is now some evidence that major depression is accompanied by activation of the inflammatory response system. There is also some evidence that antidepressants may suppress the release of cytokines, such as interleukin-1 beta (IL-1 beta) and IL-6 by activated monocytes and IL-2 and interferon-gamma (IFN gamma) by activated T cells. This study was carried out to examine the effects of clomipramine, sertraline, and trazodone on the stimulated production of IFN gamma, a pro-inflammatory cytokine, and IL-10, a negative immunoregulatory cytokine. Whole blood of nine healthy volunteers was stimulated with PHA, 5 micrograms/mL and LPS, 25 micrograms/mL for 72 hr with and without incubation with clomipramine, 10(-6) and 10(-9) M, sertraline, 10(-6) and 10(-8) M, and trazodone, 10(-6) and 10(-8) M. All three antidepressants significantly reduced IFN gamma secretion, whereas clomipramine and sertraline significantly increased IL-10 secretion in culture supernatant. All three antidepressants significantly reduced the IFN gamma/IL-10 ratio. The results suggest that antidepressants, at concentrations in the therapeutical range, have negative immunoregulatory effects through inhibition of IFN gamma and stimulation of IL-10 release.     

The integration of PET-CT scans from different hospitals into radiotherapy treatment planning.

PURPOSE: To integrate PET-CT scans from different hospitals into radiotherapy treatment planning. METHODS AND MATERIALS: A cylindrical phantom with spheres of different diameters was scanned on three different Siemens Biograph PET-CT scanners in three hospitals. The spheres and cylinder were filled with 18F-FDG such that different sphere-to-background (S/B) ratios were obtained. Scans were analyzed using dedicated software for automated delineation based on standardized uptake value (SUV) and using different reconstruction parameters. RESULTS: SUV thresholding curves for different S/B ratios were obtained for the different scanners. Differences in SUV auto-contouring thresholds were found to be significant for PET-CT simulators from different radiotherapy and nuclear medicine departments. A change in PET reconstruction parameters showed a significant effect on the results. CONCLUSION: Synchronization of PET-CT imaging protocols between cooperating hospitals is important for reliable determination of SUV auto-contouring thresholds. Whenever this goal has been achieved automated SUV delineation based on a S/B ratio using PET-CT images from different institutions can reliably be performed using individually determined threshold curves.     

Phantom pain: a sensitivity analysis

PURPOSE: To analyse how decisions to dichotomise the frequency and impediment of phantom pain into absent and present influence the outcome of studies by performing a sensitivity analysis on an existing database. METHOD: Five hundred and thirty-six subjects were recruited from the database of an orthopaedic workshop and filled out a questionnaire in which the following items were assessed: demographics, side, date, level and reason of amputation, presence and frequency of phantom sensations, phantom pain and stump pain, and impediment due to phantom pain. RESULTS: The prevalence of phantom pain ranged from 7-72% when different cut off points for the frequency of phantom pain were applied. The significance of the various risk factors for the prevalence of phantom pain changed when different cut off points were applied. Only stump pain and phantom sensations were significant risk factors for all cut off points. Risk factors for the impediment of phantom pain changed when different cut off points were applied and these risk factors were different from those for the prevalence of phantom pain. CONCLUSION: The choice of cut off points influences the outcome of phantom pain studies considerably. This study provides some insight into the differences in prevalence and risk factors found in literature.     

Localization and determination of infarct size by Gd-Mesoporphyrin enhanced MRI in dogs

Background: Accurate localization and sizing of a myocardial infarction are necessary for clinical decision making and even more in research. Gd-Mesoporphyrin enhanced magnetic resonance imaging (MRI) was recently shown to specifically delineate necrosis in liver tumors, renal and muscle necrosis and myocardial infarction in rats. In this study, we investigated this technique's potential to accurately delineate myocardial infarction in a larger animal species, the dog. Methods: Myocardial infarction was induced in 8 dogs by ligation of the left anterior descending coronary artery, 4 of which were reperfused after 3 hr. Gd-Mesoporphyrin (0.05 mmol/kg) was injected intravenously 210 min after the onset of ischemia (n = 6) or after 24 hr in 2 dogs with non-reperfused infarctions. MRI was performed 10 hr. after administration of Gd-Mesoporphyrin. In vivo MRI consisted of EKG-triggered, respiratory gated T1-weighted spin echo and segmented turboFLASH long and short axis measurements. Post-mortem, a spin echo short axis measurement was repeated. Infarct size was determined planimetrically by TTC staining of left ventricular slices. Results: In all instances, there was a very close qualitative agreement between the MRI and TTC defined myocardial infarction. Quantitatively, the linear regression from post-mortem MRI to TTC determined infarct size yielded a result very close to the line of identity (regression coefficient: 0.980 ± 0.026, p<0.000001, adjusted R² = 0.964). Conclusion: We conclude that Gd-Mesoporphyrin enhanced MRI is a promising tool for the accurate delineation of myocardial infarction.     

Depressed expression of MuRF1 and MAFbx in areas remote of recent myocardial infarction: a mechanism contributing to myocardial remodeling?

Ventricular remodeling following myocardial infarction (MI) includes myocardial hypertrophy, a process requiring increased protein synthesis and sarcomere assembly. The anti-hypertrophic effect of MuRF1/MafBx, both muscle-specific E3-ubiquitin ligases, has been demonstrated in animal experiments and in cultured cardiomyocytes. We assessed MuRF1/MAFbx expression in myocardium remote of recently (<2 weeks) infarcted regions (MI), compared with patients undergoing coronary artery bypass surgery, with normal systolic function and without previous infarction (control or Con). Left ventricular myocardial biopsies were obtained from the contralateral normal zone in MI (n = 14) patients and from the Con (n = 12) group. MuRF-1/MAFbx expression was assessed using RT-PCR and Western blot (WB). In addition, the myocardial expression of TNF-α was measured (RT-PCR) and troponin I, β-myosin and phosphorylated Akt/Akt (pAkt/Akt) were quantified (WB). MuRF1 and MAFbx expression (mRNA and protein level) were significantly reduced in biopsies from MI patients. TNF-α was significantly higher in MI and exhibited a negative correlation with MuRF1 and MAFbx. The expression of troponin I and cardiomyocyte size were increased in MI in comparison to Con, whereas β-myosin expression was not altered. When compared with Con, pAkt/Akt was elevated. The results of the present study suggest that the atrogenes MuRF1/MAFbx are involved in regulating the hypertrophic response, characteristic of the early post-infarction remodeling phase. Reduced expression of MuRF1 and MAFbx in the myocardium might permit hypertrophy, which is supported by the elevation of troponin I. A regulatory role of TNF-α needs to be confirmed in further experiments.     

Image quality assessment in digital mammography: part II. NPWE as a validated alternative for contrast detail analysis

Assessment of image quality for digital x-ray mammography systems used in European screening programs relies mainly on contrast-detail CDMAM phantom scoring and requires the acquisition and analysis of many images in order to reduce variability in threshold detectability. Part II of this study proposes an alternative method based on the detectability index (d') calculated for a non-prewhitened model observer with an eye filter (NPWE). The detectability index was calculated from the normalized noise power spectrum and image contrast, both measured from an image of a 5 cm poly(methyl methacrylate) phantom containing a 0.2 mm thick aluminium square, and the pre-sampling modulation transfer function. This was performed as a function of air kerma at the detector for 11 different digital mammography systems. These calculated d' values were compared against threshold gold thickness (T) results measured with the CDMAM test object and against derived theoretical relationships. A simple relationship was found between T and d', as a function of detector air kerma; a linear relationship was found between d' and contrast-to-noise ratio. The values of threshold thickness used to specify acceptable performance in the European Guidelines for 0.10 and 0.25 mm diameter discs were equivalent to threshold calculated detectability indices of 1.05 and 6.30, respectively. The NPWE method is a validated alternative to CDMAM scoring for use in the image quality specification, quality control and optimization of digital x-ray systems for screening mammography.     

Image quality assessment in digital mammography: part I. Technical characterization of the systems

In many European countries, image quality for digital x-ray systems used in screening mammography is currently specified using a threshold-detail detectability method. This is a two-part study that proposes an alternative method based on calculated detectability for a model observer: the first part of the work presents a characterization of the systems. Eleven digital mammography systems were included in the study; four computed radiography (CR) systems, and a group of seven digital radiography (DR) detectors, composed of three amorphous selenium-based detectors, three caesium iodide scintillator systems and a silicon wafer-based photon counting system. The technical parameters assessed included the system response curve, detector uniformity error, pre-sampling modulation transfer function (MTF), normalized noise power spectrum (NNPS) and detective quantum efficiency (DQE). Approximate quantum noise limited exposure range was examined using a separation of noise sources based upon standard deviation. Noise separation showed that electronic noise was the dominant noise at low detector air kerma for three systems; the remaining systems showed quantum noise limited behaviour between 12.5 and 380 μGy. Greater variation in detector MTF was found for the DR group compared to the CR systems; MTF at 5 mm(-1) varied from 0.08 to 0.23 for the CR detectors against a range of 0.16-0.64 for the DR units. The needle CR detector had a higher MTF, lower NNPS and higher DQE at 5 mm(-1) than the powder CR phosphors. DQE at 5 mm(-1) ranged from 0.02 to 0.20 for the CR systems, while DQE at 5 mm(-1) for the DR group ranged from 0.04 to 0.41, indicating higher DQE for the DR detectors and needle CR system than for the powder CR phosphor systems. The technical evaluation section of the study showed that the digital mammography systems were well set up and exhibiting typical performance for the detector technology employed in the respective systems.     

Malignancy after kidney transplantation: still a challenge

Long-term complications of continuous immunosuppression still remain a serious threat and are currently drawing the attention of transplant physicians. Wimmer et al. show that malignancy occurs approximately fourfold more frequently in renal-transplant recipients than in a normal control population. Besides immunosuppression, viruses probably play an important oncogenic role in transplant recipients. The retrospective analysis by Wimmer et al. suggests that mTOR inhibitors and interleukin-2 receptor antibodies are promising immunosuppressive drugs to reduce the risk of cancer after transplantation. These preliminary results must be confirmed in large, prospective, randomized, controlled trials, with long follow-up, designed to evaluate the incidence of de novo malignancy in transplant recipients.