Normalisation to Blood Activity Is Required for the Accurate Quantification of Na/I Symporter Ectopic Expression by SPECT/CT in Individual Subjects

The utilisation of the Na/I symporter (NIS) and associated radiotracers as a reporter system for imaging gene expression is now reaching the clinical setting in cancer gene therapy applications. However, a formal assessment of the methodology in terms of normalisation of the data still remains to be performed, particularly in the context of the assessment of activities in individual subjects in longitudinal studies. In this context, we administered to mice a recombinant, replication-incompetent adenovirus encoding rat NIS, or a human colorectal carcinoma cell line (HT29) encoding mouse NIS. We used 99mTc pertechnetate as a radiotracer for SPECT/CT imaging to determine the pattern of ectopic NIS expression in longitudinal kinetic studies. Some animals of the cohort were culled and NIS expression was measured by quantitative RT-PCR and immunohistochemistry. The radioactive content of some liver biopsies was also measured ex vivo. Our results show that in longitudinal studies involving datasets taken from individual mice, the presentation of non-normalised data (activity expressed as %ID/g or %ID/cc) leads to ‘noisy’, and sometimes incoherent, results. This variability is due to the fact that the blood pertechnetate concentration can vary up to three-fold from day to day. Normalisation of these data with blood activities corrects for these inconsistencies. We advocate that, blood pertechnetate activity should be determined and used to normalise the activity measured in the organ/region of interest that expresses NIS ectopically. Considering that NIS imaging has already reached the clinical setting in the context of cancer gene therapy, this normalisation may be essential in order to obtain accurate and predictive information in future longitudinal clinical studies in biotherapy

A new MRI rating scale for progressive supranuclear palsy and multiple system atrophy: validity and reliability

AIM To evaluate a standardised MRI acquisition protocol and a new image rating scale for disease severity in patients with progressive supranuclear palsy (PSP) and multiple systems atrophy (MSA) in a large multicentre study. METHODS The MRI protocol consisted of two-dimensional sagittal and axial T1, axial PD, and axial and coronal T2 weighted acquisitions. The 32 item ordinal scale evaluated abnormalities within the basal ganglia and posterior fossa, blind to diagnosis. Among 760 patients in the study population (PSP = 362, MSA = 398), 627 had per protocol images (PSP = 297, MSA = 330). Intra-rater (n = 60) and inter-rater (n = 555) reliability were assessed through Cohen's statistic, and scale structure through principal component analysis (PCA) (n = 441). Internal consistency and reliability were checked. Discriminant and predictive validity of extracted factors and total scores were tested for disease severity as per clinical diagnosis. RESULTS Intra-rater and inter-rater reliability were acceptable for 25 (78%) of the items scored (≥ 0.41). PCA revealed four meaningful clusters of covarying parameters (factor (F) F1: brainstem and cerebellum; F2: midbrain; F3: putamen; F4: other basal ganglia) with good to excellent internal consistency (Cronbach α 0.75-0.93) and moderate to excellent reliability (intraclass coefficient: F1: 0.92; F2: 0.79; F3: 0.71; F4: 0.49). The total score significantly discriminated for disease severity or diagnosis; factorial scores differentially discriminated for disease severity according to diagnosis (PSP: F1-F2; MSA: F2-F3). The total score was significantly related to survival in PSP (p<0.0007) or MSA (p<0.0005), indicating good predictive validity. CONCLUSIONS The scale is suitable for use in the context of multicentre studies and can reliably and consistently measure MRI abnormalities in PSP and MSA. Clinical Trial Registration Number The study protocol was filed in the open clinical trial registry (http://www.clinicaltrials.gov) with ID No NCT00211224

Valley-addressable polaritons in atomically thin semiconductors

The locking of the electron spin to the valley degree of freedom in transition metal dichalcogenide (TMD) monolayers has seen these materials emerge as a promising platform in valleytronics. When embedded in optical microcavities, the large oscillator strengths of excitonic transitions in TMDs allow the formation of polaritons that are part-light part-matter quasiparticles. Here, we report that polaritons in MoSe2 show an efficient retention of the valley pseudospin contrasting them with excitons and trions in this material. We find that the degree of the valley pseudospin retention is dependent on the photon, exciton and trion fractions in the polariton states. This allows us to conclude that in the polaritonic regime, cavity-modified exciton relaxation inhibits loss of the valley pseudospin. The valley-addressable exciton-polaritons and trion-polaritons presented here offer robust valley-polarized states with the potential for valleytronic devices based on TMDs embedded in photonic structures and valley-dependent nonlinear polariton–polariton interactions

Nurses' perceptions of aids and obstacles to the provision of optimal end of life care in ICU

Contains fulltext : 172380.pdf (publisher's version ) (Open Access

Passive Complementary Safety Devices for ASTRID severe accident prevention

International audienceSodium-cooled Fast Reactor is one of the Generation IV reactor concepts. It has been selected to secure the nuclear fuel resources and to manage radioactive waste. In this context, the CEA (French Commission for Atomic Energy and Alternative Energy) with its partners is involved in a substantial effort on the ASTRID (Advanced Sodium Technological Reactor for Industrial Demonstration) Project. ASTRID core design is mainly guided by safety objectives. The first one is prevention of the core meltdown accident, at first through natural favourable behaviour of the core and of the reactor, and with the addition of passive complementary systems if natural behaviour is not sufficient for some transient cases. The second one is the mitigation of the severe accident to guarantee that core melting accidents do not lead to significant mechanical energy release. The robust safety demonstration is supported by complementing ASTRID core with two types of Complementary Safety Devices dedicated to core damage prevention that would passively shut down the reactor. The first type is based on the Curie point use of electromagnetic devices that hold some specific ASTRID shutdown systems to address unprotected loss of heat sink transients (ULOHS)

Bradykinin-induced contractions of canine saphenous veins: Mediation by B2 receptors and involvement of eicosanoids

1. Experiments were designed to determine the subtype of kinin-receptors mediating the contraction of venous smooth muscle to bradykinin and to investigate the involvement of metabolites of arachidonic acid in this response. 2. Bradykinin (10-9 to 10-6 M) caused concentration-dependent contractions of the canine isolated saphenous vein without endothelium, which were potentiated by indomethacin (10-5 M, an inhibitor of cyclo-oxygenase). The concentration-response curve was biphasic, reaching an asymptote at 10-8 M and a secondary maximal response at 10-6 M. 3. Bradykinin (10-8 M to 3 x 10-6 M) caused a three fold stimulation in the release of the vasodilator prostaglandin E2 (PGE2) and a two fold stimulation of that of the vasodilator prostacyclin, measured by the production of 6-keto-PGF(1α) (its stable breakdown product). 4. Under control conditions, nordihydroguaiaretic acid (NDGA, 10-5 M), an inhibitor of lipoxygenase, did not affect the response to bradykinin. In the presence of indomethacin (10-5 M), NDGA reduced contractions to bradykinin, suggesting the involvement of lipoxygenase metabolites in the potentiation evoked by the inhibitor of cyclo-oxygenase. 5. The selective B1 receptor agonist [des-Arg9]-bradykinin, in the concentration-range 10-6 to 10-5 M, induced contractions, which were abolished by the B2 receptor antagonist D-Arg-[Hyp3,Thi5,D-Tic7,Oic8]-bradykinin (Hoe 140, 10-6 M). The selective B1 receptor antagonist [des-Arg9,Leu8]-bradykinin, (10-7 to 10-5 M) had no significant effect on bradykinin-induced contractions. 6. The B2 receptor antagonists Hoe 140 (10-8 to 10-6 M) and D-Arg[Hyp3,D-Phe7]-bradykinin (10-7 to 10-5 M) shifted the concentration-response curve to bradykinin to the right in a concentration-dependent manner. 7. These results indicate that, in the canine saphenous vein, bradykinin causes contraction by activating B2 receptors. This results in the production of metabolites of arachidonic acid, which play a key role in the contraction of canine saphenous venous smooth muscle.link_to_subscribed_fulltex

Domains of high Ca2+ beneath the plasma membrane of living A7r5 cells.

Theoretical models and indirect experimental observations predict that Ca2+ concentrations at the inner surface of the plasma membrane may reach, upon stimulation, values much higher than those of the bulk cytosol. In the past few years, we have shown that the Ca2+-sensitive photoprotein aequorin can be intracellularly targeted and utilized for specifically monitoring the [Ca2+] of various organelles. In this work, we extend this approach to the study of the cytoplasmic rim beneath the plasma membrane. We have constructed a new aequorin chimera by fusing the photoprotein with SNAP-25, a neuronal protein which is recruited to the plasma membrane after the post-translational addition of a lipid anchor. The SNAP-25-aequorin chimera, expressed in the rat aortic smooth muscle cell line A7r5, appears correctly sorted as revealed by immunocytochemistry. Using this probe, we demonstrate that the mean [Ca2+] of this cytoplasmic region ([Ca2+]pm) can reach values >10-fold higher than those of the bulk cytosol ([Ca2+]c) upon activation of Ca2+ influx through plasma membrane channels. In unstimulated cells, the mean [Ca2+]pm appears also to be higher than the bulk cytosol, presumably reflecting the existence of microdomains of high [Ca2+]