Toward clinical X-ray phase-contrast CT: demonstration of enhanced soft-tissue contrast in human specimen

X-ray computed tomography (CT) using phase contrast can provide images with greatly enhanced soft-tissue contrast in comparison to conventional attenuation-based CT. We report on the first scan of a human specimen recorded with a phase-contrast CT system based on an x-ray grating interferometer and a conventional x-ray tube source. Feasibility and potential applications of preclinical and clinical phase-contrast CT are discussed.

Implantation of the biodegradable polymer biolimus-eluting stent in patients with high SYNTAX score is associated with decreased cardiac mortality compared to a permanent polymer sirolimus-eluting stent: two year follow-up results from the "all-comers" LEADERS trial

Background: The SYNTAX score (SXscore) has been shown to be an effective predictor of clinical outcomes in patients undergoing percutaneous coronary intervention (PCI). Methods and results: The SXscore was prospectively collected in 1,397 of the 1,707 patients enrolled in the “all-comers” LEADERS trial (patients post-surgical revascularisation were excluded). Post hoc analysis was performed by stratifying clinical outcomes at two-year follow-up, according to one of three SXscore tertiles: SXlow ≤8 (n=464), 816 (n=461). At two-year follow-up the rate of major adverse cardiovascular events was 18.4%, 12.0% and 9.4% in the SXhigh, SXmid, and SXlow tertile, respectively (HR 1.45; CI 1.21-1.74; p<0.01). There was a significantly higher rate of cardiac death in patients in the highest SXscore tertile (7% SXhigh versus 2.4% SXmid versus 1.8% SXlow; HR 2.22; CI 1.5-3.27; p<0.001). Within the SXhigh tertile the rate of cardiac death was significantly lower in patients treated with the biolimus-eluting stent compared with the sirolimus-eluting stent (4.7% versus 9.6%, HR 0.48; CI 0.23-0.99; p=0.046). Conclusions: The SXscore when applied to an “all-comers” patient population allows for prospective risk stratification of patients undergoing PCI up to two years follow-up. In addition, the SXscore appears to separate the performance of devices in high risk patient groups.

Two-year follow-up of patients undergoing transcatheter aortic valve implantation using a self-expanding valve prosthesis

The purpose of this study was to evaluate the safety, device performance, and clinical outcome up to 2 years for patients undergoing transcatheter aortic valve implantation (TAVI).

Neuropsychological problems after paediatric stroke: two year follow-up of Swiss children

AIM: The aim of this study was to obtain information about neurological and cognitive outcome for a population-based group of children after paediatric ischaemic stroke. METHODS: Data from the Swiss neuropaediatric stroke registry (SNPSR), from 1.1.2000 to 1.7.2002, including children (AIS 1) and neonates (AIS 2). At 18-24 months after a stroke, a follow-up examination was performed including a history, neurological and neuropsychological assessment. RESULTS: 33/48 children (22 AIS 1, 11 AIS 2) participated in the study. Neurological outcome was good in 16/33. After childhood stroke mean IQ levels were normal (94), but 6 children had IQ < 85 (50-82) and neuropsychological problems were present in 75%. Performance IQ (93) was reduced compared to verbal IQ (101, p = 0.121) due to problems in the domain of processing speed (89.5); auditory short-term memory was especially affected. Effects on school career were common. Outcome was worse in children after right-sided infarction. Children suffering from stroke in mid-childhood had the best prognosis. There was no clear relationship between outcome and localisation of the lesion. After neonatal stroke 7/11 children showed normal development and epilepsy indicated a worse prognosis in the remaining 4. CONCLUSION: After paediatric stroke neuropsychological problems are present in about 75% of children. Younger age at stroke as well as an emergence of epilepsy were predictors for worse prognosis.

Trajectory of posttraumatic stress disorder caused by myocardial infarction: a two-year follow-up study

OBJECTIVE: A substantial proportion of patients develop posttraumatic stress disorder (PTSD) following myocardial infarction (MI). Previous research on the trajectory over time of PTSD in post-MI patients is scant and refers to self-rated posttraumatic symptoms. The aim of this study was to investigate the longitudinal course of an interviewer-rated diagnosis of PTSD and PTSD symptom severity following MI. METHODS: Study participants were 40 patients (78% men, mean age 54 +/- 8 years) who were diagnosed with PTSD using the Clinician-administered PTSD Scale (CAPS) after an average of 5 +/- 4 months (range 2-16 months) following an index MI. After a mean follow-up of 26 +/- 6 months (range 12-36 months), 24 patients underwent a second diagnostic interview. RESULTS: Two-thirds of patients (n = 16) still qualified for a diagnosis of PTSD at follow-up. In all 24 patients, total PTSD symptoms (p = 0.001), re-experiencing symptoms (p < 0.001), avoidance symptoms (p = 0.015), and, with borderline significance, hyperarousal symptoms (p < 0.06) had all decreased over time. However, in the subgroup of the 16 patients who had retained PTSD diagnostic status at follow-up, symptoms of avoidance (p = 0.23) and of hyperarousal (p = 0.48) showed no longitudinal decline. Longer duration of follow-up was associated with a greater decrease in avoidance symptoms (p = 0.029) and, with borderline significance, in re-experiencing symptoms (p < 0.07) across all patients. CONCLUSION: Although PTSD symptomatology waned over time and in relation to longer follow-up, two-thirds of patients still qualified for a diagnosis of PTSD 2 years after the initial diagnosis. In post-MI patients, clinical PTSD is a considerably persistent condition.

Two-phase change in CO2, Antarctic temperature and global climate during Termination II

The end of the Last Glacial Maximum (Termination I), roughly 20 thousand years ago (ka), was marked by cooling in the Northern Hemisphere, a weakening of the Asian monsoon, a rise in atmospheric CO2 concentrations and warming over Antarctica. The sequence of events associated with the previous glacial–interglacial transition (Termination II), roughly 136 ka, is less well constrained. Here we present high-resolution records of atmospheric CO2 concentrations and isotopic composition of N2—an atmospheric temperature proxy—from air bubbles in the EPICA Dome C ice core that span Termination II. We find that atmospheric CO2 concentrations and Antarctic temperature started increasing in phase around 136 ka, but in a second phase of Termination II, from 130.5 to 129 ka, the rise in atmospheric CO2 concentrations lagged that of Antarctic temperature unequivocally. We suggest that during this second phase, the intensification of the low-latitude hydrological cycle resulted in the development of a CO2 sink, which counteracted the CO2 outgassing from the Southern Hemisphere oceans over this period.

Circumferential distribution of the neointima at six-month and two-year follow-up after a bioresorbable vascular scaffold implantation: a substudy of the ABSORB Cohort B Clinical Trial

Aims: To investigate the extent and the circumferential distribution of the neointima tissue developed following an Absorb bioresorbable vascular scaffold (BVS) implantation. Methods and results: Twenty-three patients who were treated with the Absorb BVS and had optical coherence tomographic examination after scaffold implantation, at six-month and at two-year follow-up, were included in the current analysis. The lumen and the scaffold borders were detected and the circumferential thickness of the neointima was measured at one degree intervals. The symmetry of the neointima was defined as: minimum/maximum thickness. The lumen area was decreased at six months compared to baseline but it did not change between six-month and two-year follow-up (baseline: 7.49 [6.13-8.00] mm2, six months: 6.31 (4.75-7.06) mm2, two years: 6.01 [4.67-7.11] mm2, p=0.373). However, the mean neointima thickness (six months: 189 [173-229] μm, two years: 258 [222-283] μm, p<0.0001) and the symmetry index of the neointima (six months: 0.06 [0.02-0.09], two years: 0.27 [0.24-0.36], p<0.0001) were increased at two years. Full circumferential coverage of the vessel wall by neointima tissue was seen in 91% of the studied frames at two years. Conclusions: This study demonstrates that after an Absorb BVS implantation neointima tissue develops that covers almost the whole circumference of the vessel wall. In contrast to the metallic stents, the neointima tissue does not compromise the luminal dimensions. Further research is required to evaluate the neointimal characteristics and assess the potential value of the device in passivating high-risk plaques.

Venepuncture during head-up tilt testing in patients with suspected vasovagal syncope - implications for the test protocol.

BACKGROUND AND PURPOSE Head-up tilt (HUT) testing is a widely used diagnostic tool in patients with suspected vasovagal syncope (VVS). However, no gold standard exists for this examination and the various protocols used have a limited sensitivity and specificity. Our aim was to determine the sensitivity of a sequential HUT testing protocol including venepuncture (VP) and sublingual nitroglycerin application. METHODS This was a retrospective analysis of the diagnostic gain of a sequential HUT testing protocol including VP applied 10 min after the start of HUT testing and sublingual application of nitroglycerin 20 min after the start of the test protocol in 106 patients with a final diagnosis of VVS. The sensitivity of the test protocol was compared between patients with positive and negative history for VP induced VVS. RESULTS Overall, pre-syncope or syncope occurred in 68 patients (64.2%). Only 17% of all patients fainted spontaneously within 10 min of passive HUT. Another 39.6% fainted within 20 min. Application of nitroglycerin after 20 min of HUT evoked syncope in another 7.5% until the end of 45 min of HUT. The sensitivity of the test protocol for evoking (pre-)syncope was 94.4% in patients with a positive history for VP associated VVS and 58% in patients with a negative history (P < 0.01**); 85.7% of patients with a positive history and 42.9% of patients with a negative history fainted within 20 min of HUT testing (P < 0.01**). CONCLUSIONS Implementation of VP in sequential HUT testing protocols allows the sensitivity of HUT testing to be increased, especially in patients with a positive history for VP associated VVS.

Effects on hepatocellular carcinoma of doxorubicin-loaded immunoliposomes designed to target the VEGFR-2

To maintain a tumour vasculature in proportion of the tumour growth, the endothelial cells proliferate and up-regulate the expression of the VEGF receptor 2 (VEGFR-2), whose expression is restricted to this cell type. This specificity implies that one therapeutically target the tumour endothelium. We investigated the use of immunoliposomes (IL), containing conjugated Fab' fragments of the monoclonal rat anti-VEGFR-2 antibody DC101 (DC101-IL) to cargo doxorubicin to the tumour endothelium. In vitro, fluorescein-labelled IL displayed a 7 fold better binding to VEGFR-2-positive 293T cells in comparison to unspecific liposomes. Balb/C mice were injected subcutaneously with syngeneic hepatocellular carcinoma cells. One set of animals was treated with DC101-IL filled with doxorubicin when the tumours were bigger than 400 mm3. A specific delivery of doxorubicin to endothelial cells of the tumour vessels could be demonstrated by the red fluorescence of doxorubicin with laser scanning microscopy, but neither a delay of tumour growth nor a shrinking of the tumour mass was observed. Yet necrosis in the tumours treated with doxorubicin containing vehicles was larger than in the tumours of the control groups. A second set of animals was treated with DC101-IL filled with doxorubicin when the tumours were smaller than 1 mm3. DC101-IL filled with doxorubicin led to a significant delay in tumour growth up to 7 weeks compared to empty DC101-IL, free doxorubicin, and HEPES/Glucose (HEPES/Glucose vs. DOX-DC101-IL, p = 0.001; unpaired, two-tailed Student's t-test) and to a higher amount of necrotic areas in the tumours (p = 0.053; 1 way ANOVA with 4 groups). These findings suggest that IL designed to bind specifically to VEGFR-2 can be used to deliver doxorubicin to the tumour endothelium and may impair the "angiogenic switch" of the tumours.

Monitoring protein-protein interactions between the mammalian integral membrane transporters and PDZ-interacting partners using a modified split-ubiquitin membrane yeast two-hybrid system

PDZ-binding motifs are found in the C-terminal tails of numerous integral membrane proteins where they mediate specific protein-protein interactions by binding to PDZ-containing proteins. Conventional yeast two-hybrid screens have been used to probe protein-protein interactions of these soluble C termini. However, to date no in vivo technology has been available to study interactions between the full-length integral membrane proteins and their cognate PDZ-interacting partners. We previously developed a split-ubiquitin membrane yeast two-hybrid (MYTH) system to test interactions between such integral membrane proteins by using a transcriptional output based on cleavage of a transcription factor from the C terminus of membrane-inserted baits. Here we modified MYTH to permit detection of C-terminal PDZ domain interactions by redirecting the transcription factor moiety from the C to the N terminus of a given integral membrane protein thus liberating their native C termini. We successfully applied this "MYTH 2.0" system to five different mammalian full-length renal transporters and identified novel PDZ domain-containing partners of the phosphate (NaPi-IIa) and sulfate (NaS1) transporters that would have otherwise not been detectable. Furthermore this assay was applied to locate the PDZ-binding domain on the NaS1 protein. We showed that the PDZ-binding domain for PDZK1 on NaS1 is upstream of its C terminus, whereas the two interacting proteins, NHERF-1 and NHERF-2, bind at a location closer to the N terminus of NaS1. Moreover NHERF-1 and NHERF-2 increased functional sulfate uptake in Xenopus oocytes when co-expressed with NaS1. Finally we used MYTH 2.0 to demonstrate that the NaPi-IIa transporter homodimerizes via protein-protein interactions within the lipid bilayer. In summary, our study establishes the MYTH 2.0 system as a novel tool for interactive proteomics studies of membrane protein complexes.

Concentration-dependent isoflurane effects on withdrawal reflexes in pigs and the role of the stimulation paradigm

In this prospective two-phase experimental trial, 10 pigs were anaesthetized twice with isoflurane only. In the first phase, the individual minimum alveolar concentration (MAC) was determined and in the second phase the effects on withdrawal reflexes of increasing end-tidal isoflurane concentrations (from 1.6% to 2.8%) were assessed. Single, 10 and 60 repeated electrical stimulations were used to evoke withdrawal reflexes which were recorded and quantified by electromyography. Recruitment curves for reflex amplitude for increasing stimulation intensities and isoflurane concentrations were constructed. Isoflurane MAC was 1.9+/-0.3%. Reflexes evoked by repeated stimulation were suppressed at isoflurane concentrations significantly higher than those which suppressed complex movements during MAC determination (P=0.014 and P=0.006 for 10 and 60 repeated stimuli respectively). Isoflurane up to 2.8% was still not able to abolish reflex activity evoked by repeated stimulations in all pigs. Single stimulation reflexes were suppressed at significantly lower concentrations than repeated stimulation reflexes (P=0.008 and P=0.004 for 10 and 60 repeated stimuli, respectively). Reflex amplitude was significantly correlated with isoflurane concentration (P<0.001, r=-0.85) independent of the individual MAC. The findings indicate that the level at which isoflurane suppresses withdrawal reflexes is dependent on the stimulation paradigm (single vs. repeated electrical stimulation), and there is limited value in expressing reflex withdrawal suppression in terms of MAC as purposeful and reflex movements are independently affected by isoflurane in individual animals.

Intrapartum detection of Group B streptococci colonization by rapid PCR-test on labor ward

OBJECTIVE Group B streptococci (GBS) may lead to early onset neonatal sepsis with severe morbidity and mortality of newborns. Intrapartum detection of GBS is needed. The objective was to compare a PCR-based test performed in the laboratory versus labor ward. STUDY DESIGN 300 patients were included prospectively. In phase I, swabs were analyzed by selective culture and rapid PCR in the laboratory. In phase II, swabs were analyzed accordingly, but the PCR test was conducted in labor ward. Test performances were analyzed and compared. RESULTS In phase I the rapid PCR test had a sensitivity of 85.71% and a specificity of 95.9%. The GBS colonization rate was 18.67%. Overall 8.5% of the PCR results were invalid. In phase II the PCR test showed a sensitivity of 85.71% and a specificity of 95.65%. The GBS colonization rate was 23.3%. Overall 23.5% of swabs tested with PCR were invalid. Initiation of specific, short 2-hour training for operating personnel in the labor ward reduced the invalid test rate to 13.4%. CONCLUSION The rapid PCR-based test yields adequate results to identify GBS colonization when performed in labor ward. In order to reduce the number of invalid tests a short training period is needed.