Use of Diprivan in radiology

For radiological examinations, propofol is administered, depending on the indications, at following doses: for anxiolysis: i.v. bolus of 10-20 mg, repeated as required; for sedation with maintenance of spontaneous ventilation: i.v. bolus of 0.5 mg.kg-1 or continuous infusion of 3 mg.kg.h-1. for general anaesthesia: i.v. bolus of 2 mg.kg-1 and maintenance with a continuous infusion of 6-10 mg.kg-1.h-1. These doses are modified according to the patient's reactions and painful episodes. In neuroradiology, indications for anaesthesia include vascular explorations, MRI, computerized axial tomography, as well as biopsies of organs and tumors, with the exception of explorations in patients with tight stenoses of the carotid artery. The use of propofol for cardiological explorations is questioned in adults and mainly in children with a congenital cardiopathy. For some authors this agent is contra-indicated, as during induction it decreases, sometimes excessively, the mean arterial pressure.     

Human tracheal epithelial cells in culture: a suitable model for testing the cytocompatibility of materials for endotracheal use

It is well known that cuffs of endotracheal tubes can induce ischemic injuries on tracheal epithelium, as a result of mechanical hyperpressure caused by the cuff on the airway tissue. Whether or not material components are leached out and may provoke a direct toxic effect on the respiratory epithelium is much less clear. To study the cytocompatibility of such materials, we have developed an in vitro cell system using human tracheal epithelial cells, arising from trachea superficial biopsies. In culture, cells have been characterized by morphological and immunocytochemical criteria. Ultrastructural observations suggest that our culture conditions are permissive for the expression of both squamous and secretory phenotypes. We have assessed the cytocompatibility of a cuff towards epithelial cells, first, by an indirect test, and second by a direct test. By the indirect test, using material extracts, we did not find any toxic effect towards human airway epithelial cells of the cuff components. By a direct test, we found a slight cell lysis after a 24 h incubation. Our study shows that this human tracheal epithelial cell system is a useful and relevant model which could be used in a quality control procedure for testing the cytocompatibility of materials for endotracheal use.     

Impact of heterozygosity for the chemokine receptor CCR5 32-bp-deleted allele on plasma virus load and CD4 T lymphocytes in perinatally human immunodeficiency virus-infected children at 8 years of age

The CCR5 gene encodes one of the major human immunodeficiency virus type 1 (HIV-1) coreceptors. A 32-bp deletion in this gene (delta ccr5) is associated with relative resistance to disease progression in heterozygous HIV-1-infected persons. The effect of this mutation on virologic and immunologic parameters was determined in a cohort of 45 perinatally HIV-1-infected children prospectively followed after 5 years of age. At a median age of 8.3 years, heterozygous children had significantly lower virus load than homozygous children (median, 3.3 vs. 4.1 log copies/mL, P < .009) and higher percentages of CD4 T cells (median, 26% vs. 17%, P < .07). However, there was no discernible influence of the CCR5 genotype on the percentages of CD8 T cells (P < .27) or on HIV-specific cytotoxic T lymphocyte activities (P < .65). There was a trend for lower rates of progression to AIDS (CDC stage C) in heterozygous children. These data confirm a major role for the CCR5 coreceptor in HIV-1 pathogenesis in children.     

A canine ex vivo shunt for isotopic hemocompatibility evaluation of a NHLBI DTB primary reference material and of a IUPAC reference material

Factors determining the thrombogenic response to particular artificial surfaces were investigated ex vivo in a canine shunt model. Methods using radioisotopic tracers made it possible to dynamically monitor the deposition of labelled blood cells and proteins on a NHLBI.DTB primary reference material polydimethylsiloxane (PRM.PDMS) and on a IUPAC reference material polyvinyl chloride (IUPAC.PVC). On the one hand, leukocyte affinity tau s(leu) (number of deposited leukocytes mm-2s-1) was not significantly different between IUPAC.PVC (tau s(leu) = 1.2-2.5) and PRM.PDMS (tau s(leu) = 1.5-3.4) and the fibrinogen adsorption rate varied from 33 to 48.10(-5) micrograms mm-2s-1 for both these materials. On the other hand, platelet affinity tau s(plat) (number of deposited platelets mm-2s-1) was significantly different (p < 0.05) for IUPAC.PVC and PRM.PDMS (tau s(plat)PVC = 683 +/- 200 > tau s(plat)PDMS = 327 +/- 80). Scanning electron micrographs of adherent platelets, red cells and leukocytes after blood contact ex vivo were performed after each experiment. This preliminary work contributes not only to quantify the adsorption of different radiotracers, but also to evaluate the superficial distribution of the labelled biological species on the inner surface of the tested biomaterials.     

High-frequency four noise parameters of silicon-on-insulator-basedtechnology MOSFET for the design of low-noise RF integratedcircuits

An exhaustive experimental study of the high-frequency noise properties of MOSFET in silicon-on-insulator (SOI) technology is presented. Various gate geometries are fabricated to study the influence of effective channel length, gate finger width, and gate sheet resistivity on the four noise parameters. The high level of MOSFET sensitivity to the minimum noise matching condition is demonstrated. From experimental results, optimal ways to realize ultra low noise amplifiers are discussed. The capability of the fully depleted standard SOI CMOS process for realizing low-noise amplifiers for multigigahertz portable communication systems is shown     

The -700/-310 fragment of the apolipoprotein A-IV gene combined with the -890/-500 apolipoprotein C-III enhancer is sufficient to direct a pattern of gene expression similar to that for the endogenous apolipoprotein A-IV gene

Spatial gene expression in the intestine is mediated by specific regulatory sequences. The three genes of the apoA-I/C-III/A-IV cluster are expressed in the intestine following cephalocaudal and crypt-to-villus axes. Previous studies have shown that the -780/-520 enhancer region of the apoC-III gene directs the expression of the apoA-I gene in both small intestinal villi and crypts, implying that other unidentified elements are necessary for a normal intestinal pattern of apoA-I gene expression. In this study, we have characterized transgenic mice expressing the chloramphenicol acetyltransferase gene under the control of different regions of the apoC-III and apoA-IV promoters. We found that the -890/+24 apoC-III promoter directed the expression of the reporter gene in crypts and villi and did not follow a cephalocaudal gradient of expression. In contrast, the -700/+10 apoA-IV promoter linked to the -500/-890 apoC-III enhancer directed the expression of the reporter gene in enterocytes with a pattern of expression similar to that of the endogenous apoA-IV gene. Furthermore, linkage of the -700/-310 apoA-IV distal promoter region to the -890/+24 apoC-III promoter was sufficient to restore the appropriate pattern of intestinal expression of the reporter gene. These findings demonstrate that the -700/-310 distal region of the apoA-IV promoter contains regulatory elements that, in combination with proximal promoter elements and the -500/-890 enhancer, are necessary and sufficient to restrict apoC-III and apoA-IV gene expression to villus enterocytes of the small intestine along the cephalocaudal axis.     

Left ventricular diastolic function: physiology, physiopathology, evaluation, therapy, consequences of anesthesia

With the exception of cardiac surgery, the acute disturbance of the left ventricular diastole occurs mainly in the elderly. Today it represents 30 to 40% of congestive cardiac failures, however with a lower mortality than for acute systolic disturbances. Generally indicated are relaxation anomalies, proto-mesodiastolic mechanism and problems with compliance, an indicator of the pressure/volume diastolic relationship. Invasive techniques remain the standard method. Doppler echocardiography is becoming increasingly important for the assessment of diastolic function. In most cardiopathies, relaxation anomalies occur early, whereas compliance disturbances are mainly associated with advanced cardiac diseases. During anaesthesia, adverse events (auricular fibrillation, hypovolaemia) may worsen a fragile situation. Anaesthetic agents, in particular volatile agents, act on the ventricular diastole. Long-term therapy of diastolic anomalies includes agents amending left ventricular hypertrophy. Emergency therapy has not yet been systematised.     

Intra-hepatic post-traumatic cholestasis. Apropos of 22 cases

The authors report 22 observations of patients showing an intra-hepatic cholestasis following a traumatism. The frequency of this complication amounted to about 1.5 p. 100. Among the mechanisms of this cholestasis some factors were kept in mind: 1. the severity of the traumatism; 2. the surgical act; 3. the use of massive transfusions, the polyvisceral complications of the traumatic shock, the infectious complications. The pathophysiology of this cholestasis seems to be in relation to an increase of the production of the conjugated bilirubin. This production is associated with a decrease of the biliary excretion depending essentially on hepatic intracellular injury, secondary to: the hemorragic shock, the anoxia, the surgical intervention, the infection. From these different factors, they draw practical conclusions as much in the diagnosis of cholestasis as in the therapeutics.     

Irradiation behavior of experimental fuel particles containing chemically vapor deposited zirconium carbide coatings

Four experimental fuel particle designs, utilizing zirconium carbide coatings in combination with porous and dense pyrocarbon coatings, were tested under high-temperature irradiation. As a fission-product corrosion test for the zirconium carbide, two particle designs employed carbide coatings applied directly over either UC₂ or (8Th, 1U)O₂ fuel kernels. The other two designs utilized zirconium carbide outside of porous pyrocarbon coatings but without the conventional inner dense pyrocarbon coating on either UC₂ or (8Th, 1U)O₂ fuel kernels. The particles were irradiated at 1200°C to a fast-neutron fluence of $\text{5 × 10}{}^{21}\text{n/cm}{}^2\text{(E μ'0.18 MeV)}$ and fractional burnups of the initial metal atoms of 0.7 and 0.08 for the UC₂ and (8Th, 1U)O₂ kernels, respectively. Stereoscopic, metallographic and electron-beam microprobe examination of the irradiated particles showed that the zirconium carbide possesses exceptional resistance to chemical attack by fission products and good mechanical stability under irradiation.     

Information-theoretic temporal segmentation of video and applications: multiscale keyframes selection and shot boundaries detection

The first step in the analysis of video content is the partitioning of a long video sequence into short homogeneous temporal segments. The homogeneity property ensures that the segments are taken by a single camera and represent a continuous action in time and space. These segments can then be used as atomic temporal components for higher level analysis like browsing, classification, indexing and retrieval. The novelty of our approach is to use color information to partition the video into segments dynamically homogeneous using a criterion inspired by compact coding theory. We perform an information-based segmentation using a Minimum Message Length (MML) criterion and minimization by a Dynamic Programming Algorithm (DPA). We show that our method is efficient and robust to detect all types of transitions in a generic manner. A specific detector for each type of transition of interest therefore becomes unnecessary. We illustrate our technique by two applications: a multiscale keyframe selection and a generic shot boundaries detection.