Single-stranded oligonucleotide-mediated in vivo gene repair in the rd1 retina.

PURPOSE: The aim of this study was to test whether oligonucleotide-targeted gene repair can correct the point mutation in genomic DNA of PDE6b(rd1) (rd1) mouse retinas in vivo. METHODS: Oligonucleotides (ODNs) of 25 nucleotide length and complementary to genomic sequence subsuming the rd1 point mutation in the gene encoding the beta-subunit of rod photoreceptor cGMP-phosphodiesterase (beta-PDE), were synthesized with a wild type nucleotide base at the rd1 point mutation position. Control ODNs contained the same nucleotide bases as the wild type ODNs but with varying degrees of sequence mismatch. We previously developed a repeatable and relatively non-invasive technique to enhance ODN delivery to photoreceptor nuclei using transpalpebral iontophoresis prior to intravitreal ODN injection. Three such treatments were performed on C3H/henJ (rd1) mouse pups before postnatal day (PN) 9. Treatment outcomes were evaluated at PN28 or PN33, when retinal degeneration was nearly complete in the untreated rd1 mice. The effect of treatment on photoreceptor survival was evaluated by counting the number of nuclei of photoreceptor cells and by assessing rhodopsin immunohistochemistry on flat-mount retinas and sections. Gene repair in the retina was quantified by allele-specific real time PCR and by detection of beta-PDE-immunoreactive photoreceptors. Confirmatory experiments were conducted using independent rd1 colonies in separate laboratories. These experiments had an additional negative control ODN that contained the rd1 mutant nucleotide base at the rd1 point mutation site such that the sole difference between treatment with wild type and control ODN was the single base at the rd1 point mutation site. RESULTS: Iontophoresis enhanced the penetration of intravitreally injected ODNs in all retinal layers. Using this delivery technique, significant survival of photoreceptors was observed in retinas from eyes treated with wild type ODNs but not control ODNs as demonstrated by cell counting and rhodopsin immunoreactivity at PN28. Beta-PDE immunoreactivity was present in retinas from eyes treated with wild type ODN but not from those treated with control ODNs. Gene correction demonstrated by allele-specific real time PCR and by counts of beta-PDE-immunoreactive cells was estimated at 0.2%. Independent confirmatory experiments showed that retinas from eyes treated with wild type ODN contained many more rhodopsin immunoreactive cells compared to retinas treated with control (rd1 sequence) ODN, even when harvested at PN33. CONCLUSIONS: Short ODNs can be delivered with repeatable efficiency to mouse photoreceptor cells in vivo using a combination of intravitreal injection and iontophoresis. Delivery of therapeutic ODNs to rd1 mouse eyes resulted in genomic DNA conversion from mutant to wild type sequence, low but observable beta-PDE immunoreactivity, and preservation of rhodopsin immunopositive cells in the outer nuclear layer, suggesting that ODN-directed gene repair occurred and preserved rod photoreceptor cells. Effects were not seen in eyes treated with buffer or with ODNs having the rd1 mutant sequence, a definitive control for this therapeutic approach. Importantly, critical experiments were confirmed in two laboratories by several different researchers using independent mouse colonies and ODN preparations from separate sources. These findings suggest that targeted gene repair can be achieved in the retina following enhanced ODN delivery.

Impact of HSD11B1 polymorphisms on BMI and components of the metabolic syndrome in patients receiving psychotropic treatments.

BACKGROUND: Metabolic syndrome (MetS) associated with psychiatric disorders and psychotropic treatments represents a major health issue. 11β-Hydroxysteroid dehydrogenase type 1 (11β-HSD1) is an enzyme that catalyzes tissue regeneration of active cortisol from cortisone. Elevated enzymatic activity of 11β-HSD1 may lead to the development of MetS. METHODS: We investigated the association between seven HSD11B1 gene (encoding 11β-HSD1) polymorphisms and BMI and MetS components in a psychiatric sample treated with potential weight gain-inducing psychotropic drugs (n=478). The polymorphisms that survived Bonferroni correction were analyzed in two independent psychiatric samples (nR1=168, nR2=188) and in several large population-based samples (n1=5338; n2=123 865; n3>100 000). RESULTS: HSD11B1 rs846910-A, rs375319-A, and rs4844488-G allele carriers were found to be associated with lower BMI, waist circumference, and diastolic blood pressure compared with the reference genotype (Pcorrected<0.05). These associations were exclusively detected in women (n=257) with more than 3.1 kg/m, 7.5 cm, and 4.2 mmHg lower BMI, waist circumference, and diastolic blood pressure, respectively, in rs846910-A, rs375319-A, and rs4844488-G allele carriers compared with noncarriers (Pcorrected<0.05). Conversely, carriers of the rs846906-T allele had significantly higher waist circumference and triglycerides and lower high-density lipoprotein-cholesterol exclusively in men (Pcorrected=0.028). The rs846906-T allele was also associated with a higher risk of MetS at 3 months of follow-up (odds ratio: 3.31, 95% confidence interval: 1.53-7.17, Pcorrected=0.014). No association was observed between HSD11B1 polymorphisms and BMI and MetS components in the population-based samples. CONCLUSIONS: Our results indicate that HSD11B1 polymorphisms may contribute toward the development of MetS in psychiatric patients treated with potential weight gain-inducing psychotropic drugs, but do not play a significant role in the general population.

Micro-Structural Brain Alterations in Aviremic HIV+ Patients with Minor Neurocognitive Disorders: A Multi-Contrast Study at High Field.

OBJECTIVE: Mild neurocognitive disorders (MND) affect a subset of HIV+ patients under effective combination antiretroviral therapy (cART). In this study, we used an innovative multi-contrast magnetic resonance imaging (MRI) approach at high-field to assess the presence of micro-structural brain alterations in MND+ patients. METHODS: We enrolled 17 MND+ and 19 MND- patients with undetectable HIV-1 RNA and 19 healthy controls (HC). MRI acquisitions at 3T included: MP2RAGE for T1 relaxation times, Magnetization Transfer (MT), T2* and Susceptibility Weighted Imaging (SWI) to probe micro-structural integrity and iron deposition in the brain. Statistical analysis used permutation-based tests and correction for family-wise error rate. Multiple regression analysis was performed between MRI data and (i) neuropsychological results (ii) HIV infection characteristics. A linear discriminant analysis (LDA) based on MRI data was performed between MND+ and MND- patients and cross-validated with a leave-one-out test. RESULTS: Our data revealed loss of structural integrity and micro-oedema in MND+ compared to HC in the global white and cortical gray matter, as well as in the thalamus and basal ganglia. Multiple regression analysis showed a significant influence of sub-cortical nuclei alterations on the executive index of MND+ patients (p = 0.04 he and R(2) = 95.2). The LDA distinguished MND+ and MND- patients with a classification quality of 73% after cross-validation. CONCLUSION: Our study shows micro-structural brain tissue alterations in MND+ patients under effective therapy and suggests that multi-contrast MRI at high field is a powerful approach to discriminate between HIV+ patients on cART with and without mild neurocognitive deficits.

Brain network analysis of patients with Temporal Lobe Epilepsy

Patients with Temporal Lobe Epilepsy (TLE) suffer from widespread subtle white matter abnormalities and abnormal functional connectivity extending beyond the affected lobe, as revealed by Diffusion Tensor MR Imaging, volumetric and functional MRI studies. Diffusion Spectrum Imaging (DSI) is a diffusion imaging technique with high angular resolution for improving the mapping of white matter pathways. In this study, we used DSI, connectivity matrices and topological measures to investigate how the alteration in structural connectivity influences whole brain structural networks. Eleven patients with right-sided TLE and hippocampal sclerosis and 18 controls underwent our DSI protocol at 3T. The cortical and subcortical grey matters were parcellated into 86 regions of interest and the connectivity between every region pair was estimated using global tractography and a connectivity matrix (the adjacency matrix of the structural network). We then compared the networks of patients and controls using topological measures. In patients, we found a higher characteristic path length and a lower clustering coefficient compared to controls. Local measures at node level of the clustering and efficiency showed a significant difference after a multiple comparison correction (Bonferroni). These significant nodes were located within as well outside the temporal lobe, and the localisation of most of them was consistent with regions known to be part of epileptic networks in TLE. Our results show altered connectivity patterns that are concordant with the mapping of functional epileptic networks in patients with TLE. Further studies are needed to establish the relevance of these findings for the propagation of epileptic activity, cognitive deficits in medial TLE and outcome of epilepsy surgery in individual patients.

A genome-wide significant linkage for severe depression on chromosome 3: the depression network study.

Objective: The purpose of this study was to find loci for major depression via linkage analysis of a large sibling pair sample. Method: The authors conducted a genome-wide linkage analysis of 839 families consisting of 971 affected sibling pairs with severe recurrent major depression, comprising waves I and II of the Depression Network Study cohort. In addition to examining affected status, linkage analyses in the full data set were performed using diagnoses restricted by impairment severity, and association mapping of hits in a large case-control data set was attempted. Results: The authors identified genome-wide significant linkage to chromosome 3p25-26 when the diagnoses were restricted by severity, which was a maximum LOD score of 4.0 centered at the linkage marker D3S1515. The linkage signal identified was genome-wide significant after correction for the multiple phenotypes tested, although subsequent association mapping of the region in a genome-wide association study of a U.K. depression sample did not provide significant results. Conclusions: The authors report a genome-wide significant locus for depression that implicates genes that are highly plausible for involvement in the etiology of recurrent depression. Despite the fact that association mapping in the region was negative, the linkage finding was replicated by another group who found genome-wide-significant linkage for depression in the same region. This suggests that 3p25-26 is a new locus for severe recurrent depression. This represents the first report of a genome-wide significant locus for depression that also has an independent genome-wide significant replication.

Accès sans prescription aux statines: bénéfique ou délétère. [Over-the-counter statins: benefit or harmful?]

Making statin available over the counter is one of the measures proposed to correct its underuse. Since May 2004, simvastatin 10 mg is sold over the counter in Great Britain. But uncertainties persist concerning the efficacy of statin in primary prevention and at a 10 mg dose. Finally, there is a risk of side effects and drug interactions. Beyond the correction of statin underuse and the hope of coronary heart disease mortality reduction, the British decision highlighted the will to give individuals a sense of responsibility concerning their health and its financial cost. Anyway, the benefit of switching statin from prescription to over the counter should be experimentally evaluated before its introduction.

Chirurgie de l'avant-pied: quoi de neuf [What's new in forefoot surgery].

New implants and instruments have recently emerged in foot surgery. However, an additional and important development is the technique of minimally invasive surgery. As a result of new surgical approaches some common foot deformities can be corrected in a percutaneous manner. The benefits include improved wound healing, less pain, faster recovery, and less need for outpatient care. The main indications for such a technique are hallux valgus, correction of the lesser metatarsals, hallux rigidus, and some diabetic foot deformities.

3-d residual eddy current field characterisation: applied to diffusion weighted magnetic resonance imaging.

Clinical use of the Stejskal-Tanner diffusion weighted images is hampered by the geometric distortions that result from the large residual 3-D eddy current field induced. In this work, we aimed to predict, using linear response theory, the residual 3-D eddy current field required for geometric distortion correction based on phantom eddy current field measurements. The predicted 3-D eddy current field induced by the diffusion-weighting gradients was able to reduce the root mean square error of the residual eddy current field to ~1 Hz. The model's performance was tested on diffusion weighted images of four normal volunteers, following distortion correction, the quality of the Stejskal-Tanner diffusion-weighted images was found to have comparable quality to image registration based corrections (FSL) at low b-values. Unlike registration techniques the correction was not hindered by low SNR at high b-values, and results in improved image quality relative to FSL. Characterization of the 3-D eddy current field with linear response theory enables the prediction of the 3-D eddy current field required to correct eddy current induced geometric distortions for a wide range of clinical and high b-value protocols.

Hypertension portale et prise en charge de l'ascite [Management of ascites due to portal hypertension].

Portal hypertension is regularly encountered by the general practitioner. It is defined by an elevation of the porto-systemic pressure gradient, with complications such as ascites, spontaneous bacterial peritonitis, hepatorenal syndrome, variceal bleeding, hypersplenism, hepatopulmonary syndrome or hepatic encephalopathy occuring when a significant elevation of this gradient is reached. Cirrhosis is the primary cause of portal hypertension in industrialized countries. Symptomatic portal hypertension carries a poor prognosis. Management should be initiated rapidly, including the identification and correction of any reversible underlying condition. Liver transplantation should be considered in advanced cases.

Is intra-operative blood fllow predictive for early failure of radiocephalic arteriovenous fistula ?

Rapport de Synthèse : Introduction : Depuis plus de 50 ans, les fistules artérioveineuses radiocéphaliques (FAV) restent le meilleur accès d'hémodialyse en termes de perméabilité et de complications. Néanmoins, l'échec précoce dû aux thromboses ou à la non maturation entraîne leur abandon chez un nombre significatif de patients. Cette étude prospective est destinée à investiguer la mesure peropératoire du débit sanguin dans les FAV comme valeur prédictive d'échec précoce. Méthode : Nous avons sélectionné des patients nécessitant la confection d'une FAV pour hémodialyse en se basant sur le repérage veineux effectué par ultrason dans la période préopératoire. La mesure du débit sanguin dans la FAV a été réalisée systématiquement après la réalisation de l'anastomose en utilisant une sonde mesurant le temps de transit des globules rouges. Durant le suivi, le débit a été estimé par ultrason à des intervalles réguliers. Résultats : Nous avons réalisés 58 FAV chez 58 patients avec un suivi moyen de 30 jours. La thrombose et non maturation a été observée chez 8 patients (14%) et 4 patients (7%) respectivement. La valeur de débit peropératoire des fistules sans échec précoce était significativement plus élevée que dans les fistules avec échec précoce (230 v. 98 mL/min ; Ρ = 0.007), tout comme à une semaine (753 vs 228 mL/min ; P=0.0008) et 4 semaines (915 vs 245 mL/min, P<0.0001j. La mesure du débit avec une valeur seuil à 120 mL/min présente une sensibilité de 67%, une spécificité de 75% et une valeur prédictive positive de 91%. Conclusions : Un débit sanguin < 120mL/min a une bonne valeur prédictive positive d'échec précoce dans les FAV. Durant la procédure, cette valeur seuil, doit être utilisée pour sélectionner de manière appropriée les FAV nécessitant durant la même intervention une correction immédiate afin d'améliorer le débit. Une étude consécutive devra investiguer les origines des débits faibles des FAV objectivés durant leur confection.

Assessment of myocardial edema and area-at-risk in acute myocardial infarction by CMR: Evaluation of a novel T2-mapping method

Objectives. The goal of this study is to evaluate a T2-mapping sequence by: (i) measuring the reproducibility intra- and inter-observer variability in healthy volunteers in two separate scanning session with a T2 reference phantom; (2) measuring the mean T2 relaxation times by T2-mapping in infarcted myocardium in patients with subacute MI and compare it with patient's the gold standard X-ray coronary angiography and healthy volunteers results. Background. Myocardial edema is a consequence of an inflammation of the tissue, as seen in myocardial infarct (MI). It can be visualized by cardiovascular magnetic resonance (CMR) imaging using the T2 relaxation time. T2-mapping is a quantitative methodology that has the potential to address the limitation of the conventional T2-weighted (T2W) imaging. Methods. The T2-mapping protocol used for all MRI scans consisted in a radial gradient echo acquisition with a lung-liver navigator for free-breathing acquisition and affine image registration. Mid-basal short axis slices were acquired.T2-maps analyses: 2 observers semi- automatically segmented the left ventricle in 6 segments accordingly to the AHA standards. 8 healthy volunteers (age: 27 ± 4 years; 62.5% male) were scanned in 2 separate sessions. 17 patients (age : 61.9 ± 13.9 years; 82.4% male) with subacute STEMI (70.6%) and NSTEMI underwent a T2-mapping scanning session. Results. In healthy volunteers, the mean inter- and intra-observer variability over the entire short axis slice (segment 1 to 6) was 0.1 ms (95% confidence interval (CI): -0.4 to 0.5, p = 0.62) and 0.2 ms (95% CI: -2.8 to 3.2, p = 0.94, respectively. T2 relaxation time measurements with and without the correction of the phantom yielded an average difference of 3.0 ± 1.1 % and 3.1 ± 2.1 % (p = 0.828), respectively. In patients, the inter-observer variability in the entire short axis slice (S1-S6), was 0.3 ms (95% CI: -1.8 to 2.4, p = 0.85). Edema location as determined through the T2-mapping and the coronary artery occlusion as determined on X-ray coronary angiography correlated in 78.6%, but only in 60% in apical infarcts. All except one of the maximal T2 values in infarct patients were greater than the upper limit of the 95% confidence interval for normal myocardium. Conclusions. The T2-mapping methodology is accurate in detecting infarcted, i.e. edematous tissue in patients with subacute infarcts. This study further demonstrated that this T2-mapping technique is reproducible and robust enough to be used on a segmental basis for edema detection without the need of a phantom to yield a T2 correction factor. This new quantitative T2-mapping technique is promising and is likely to allow for serial follow-up studies in patients to improve our knowledge on infarct pathophysiology, on infarct healing, and for the assessment of novel treatment strategies for acute infarctions.

Evaluation of the quantity of Fe3+ in spinels for obtaining the oxygen fugacities in xenoliths.

The analysis by electron microprobe allows the evaluation of the quantity of Fe3+ ih spinels with considerable errors. The use of a correction equation which is based on a the calibration of analyses with an electron microprobe in relation to those carried out with Mossbauer spectroscopy gives more precise evaluations of Fe3+. In fact, it allows a calculation of the oxygen fugacity in peridotitic xenoliths. The obtained results show that peridotites of the French Central Massif crystallised under oxygen fugacities which were higher than those of the Moroccan Anti-Atlas.

Visual loss after orthopedic procedures.

Perioperative visual loss (PVL) is a very rare and unpredictable complication of surgery performed at distance from the visual pathways, mostly after spine or cardiac procedures. We report 6 consecutive patients with PVL after routine orthopedic procedures (osteosynthesis for complex fracture of the femur [2], total hip arthroplasty [2], hip prosthesis arthroplasty [1], bilateral simultaneous total knee arthroplasty [1]) and reviewed the literature on the subject. An ischemic optic neuropathy was diagnosed in all cases, and visual loss was bilateral in 5 of 6 patients. Partial visual improvement occurred in only 3 of 11 eyes. No specific therapy is available for PVL. Postoperative visual disturbances should prompt without delay an ophthalmic evaluation because emergent correction of anemia, systemic hypotension, or hypovolemia might improve visual prognosis of PVL.

Determining the activity of Pu-241 by liquid scintillation counting

Liquid scintillation counting (LSC) is one of the most widely used methods for determining the activity of 241Pu. One of the main challenges of this counting method is the efficiency calibration of the system for the low beta energies of 241Pu (Emax = 20.8 keV). In this paper we compare the two most frequently used methods, the CIEMAT/NIST efficiency tracing (CNET) method and the experimental quench correction curve method. Both methods proved to be reliable, and agree within their uncertainties, for the expected quenching conditions of the sources.

Fonction surrénalienne après bolus d'étomidate en chirurgie cardiaque : une étude rétrospective

Rapport de synthèse : Enjeux et contexte Etant le seul agent hypnotique à avoir des effets hémodynamiques négligeables, l'étomidate est souvent considéré comme l'agent anesthésique d'induction de choix lors de l'anesthésie de patients hémodynamiquement instables Cependant, une dose unique de cet hypnotique imidazolé inhibe la 11-ß hydroxylase, une enzyme mitochondriale de la phase terminale de la synthèse du cortisol. Au Centre Hospitalier Universitaire Vaudois, tout patient candidat à une chirurgie cardiaque reçoit de l'étomidate à l'induction de l'anesthésie. L'objectif de cette étude a été de déterminer l'incidence de dysfonction surrénalienne chez les patients subissant une chirurgie cardiaque et présentant un état de choc postopératoire nécessitant de hautes doses de noradrénaline. t Méthodes Une étude rétrospective et descriptive a été réalisée dans le service de médecine intensive adulte du Centre Hospitalier Universitaire Vaudois. Soixante-trois patients admis en réanimation après chirurgie cardiaque nécessitant plus de 0.2 νg/kg/min de noradrénaline au cours des premières 48 heures postopératoires ont été étudiés. L'insuffisance surrénalienne absolue a été définie par un cortisol basal inférieur à 414mmo/L, l'insuffisance surrénalienne relative par un cortisol basal entre 414mmo/L et 938nmo/L avec augmentation de la cortisolémie (à 60 minute .après un test de stimulation par 250Ng of corticotropine de synthèse) inférieure à 250mmo/L. Statistiques Les résultats ont été rapportés en médianes et extrêmes. Les comparaisons entre les groupes ont été réalisées, lorsque cela était indiqué, par un test Chi 2 ou un test de Wilcoxon. Pour les comparaisons répétées des taux de cortisol et des doses de noradrénaline, une correction de Bonferroni a été appliquée. Une valeur de p<0,05 a été considérée comme significative. Résultats : Quatorze patients [22%] ont présenté une fonction surrénalienne normale, 10 [16%] une insuffisance surrénalienne absolue et 39 [62%] une insuffisance surrénalienne relative. Tous les patients ont reçu une substitution stéroïdienne, sans aucune différence d'évolution clinique entre les différents groupes. Conclusions : L'incidence d'insuffisance surrénalienne chez les patients qui ont reçu un bolus d'étomidate à l'induction, subi une chirurgie cardiaque avec circulation extra-corporelle et présenté une défaillance circulatoire postopératoire est élevée. Il convient probablement de garder à l'esprit qu'une telle insuffisance peut contribuer à l'état de choc du patient. Dans de telles circonstances, l'exploration de la fonction surrénalienne et la suppléance par stéroïdes d'une éventuelle insuffisance surrénalienne en attendant les résultats des examens endocrinologiques devraient être discutés.