Assessment of organ dose and image quality in head and chest CT examinations: a phantom study.

The purpose of this study is to assess dose for radiosensitive organs and image quality in head and chest computed tomography (CT) examinations. Our focus was in the brain, eye lens and lung organs using two protocols; one protocol with fixed mAs and filtered back projection (FBP) and another with tube current modulation (TCM) and sinogram affirmed iterative reconstruction (SAFIRE). Measurements were performed on a 128-slice CT scanner by placing thermoluminescent dosimeters (TLDs) in an anthropomorphic adult phantom. Results were compared to a CT-Expo software. Objective image quality was assessed in terms of signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). SPSS software was used for data analyses. Results showed that, using TCM, doses were reduced by 22.84%-25.06% for brain, by 21.82%-23.48% for eye lens and by 54%-53.22% for lung with TLD and CT-Expo respectively. The increased SNR and CNR values achieved for scans performed with TCM combined with iterative reconstruction techniques were 38.68%-58.81% and 38.91%-43.60% respectively. We conclude that, using TCM, a significant mean organ dose reduction is achieved for brain, eye lens and lung organs. Then, combined with iterative reconstruction, image quality was well maintained in terms of SNR and CNR. Thus it is highly recommended in clinical practice optimization in head and chest CT examinations.

Tunisian tomato by-products, as a potential source of natural bioactive compounds.

Consumption of tomato and tomato products is positively related to the reduction in cardiovascular disease and several types of cancer, thanks to the presence of natural compounds, such as antioxidants. Peels and seeds fractions of tomato, collected after industrial processing in Tunisian industries, were analysed for nutritional and antioxidants composition in perspective of its utilisation. Proximate composition, fatty acids profile, carotenoids, such as lycopene and beta-carotene, polyphenols contents, demonstrated the good potential of these residual products as a source of natural compounds, useful for food and nutraceuticals applications.

Localised impedance monitoring device for the remote clinical assessment of home-based dialysis patients.

BioImpedance Spectroscopy (BIS) has been clinically used to determine the hydrational status of patients undergoing haemodialysis (HD). In the present project we are developing a calf-localised, integrated impedimetric device to periodically and conveniently measure and transmit information on the hydrational status of home-based patients to a remote clinic. Surprisingly, we have found that simple postural changes before or during measurement lead to significant fluid shifts in the lower leg that are as important and as long lasting as the effects of haemodialysis. These must be taken into account if potentially hazardous errors are not to be made in assessing a patient's hydrational status.

Wearable impedance monitoring system for dialysis patients.

This paper describes the development and the validation of a prototype wearable miniaturized impedance monitoring system for remote monitoring in home-based dialysis patients. This device is intended to assess the hydration status of dialysis patients using calf impedance measurements. The system is based on the low-power AD8302 component. The impedance calibration procedure is described together with the Cole parameter estimation and the hydric volume estimation. Results are given on a test cell to validate the design and on preliminary calf measurements showing Cole parameter variations during hemodialysis.

Spanish human proteome project: dissection of chromosome 16.

The Chromosome 16 Consortium forms part of the Human Proteome Project that aims to develop an entire map of the proteins encoded by the human genome following a chromosome-centric strategy (C-HPP) to make progress in the understanding of human biology in health and disease (B/D-HPP). A Spanish consortium of 16 laboratories was organized into five working groups: Protein/Antibody microarrays, protein expression and Peptide Standard, S/MRM, Protein Sequencing, Bioinformatics and Clinical healthcare, and Biobanking. The project is conceived on a multicenter configuration, assuming the standards and integration procedures already available in ProteoRed-ISCIII, which is encompassed within HUPO initiatives. The products of the 870 protein coding genes in chromosome 16 were analyzed in Jurkat T lymphocyte cells, MCF-7 epithelial cells, and the CCD18 fibroblast cell line as it is theoretically expected that most chromosome 16 protein coding genes are expressed in at least one of these. The transcriptome and proteome of these cell lines was studied using gene expression microarray and shotgun proteomics approaches, indicating an ample coverage of chromosome 16. With regard to the B/D section, the main research areas have been adopted and a biobanking initiative has been designed to optimize methods for sample collection, management, and storage under normalized conditions and to define QC standards. The general strategy of the Chr-16 HPP and the current state of the different initiatives are discussed.

A modular 256-channel micro electrode array platform for in vitro and in vivo neural stimulation and recording: BioMEA.

In order to understand the dynamics of large neural networks, where information is widely distributed over thousands of cells, one of today's challenges is to successfully monitor the simultaneous activity of as many neurons as possible. This is made possible by using the Micro-Electrode Array (MEA) technology allowing neural cell culture and/or tissue slice experimentation in vitro. Thanks to development of microelectronics' technologies, a novel data acquisition system based on MEA technology has been developed, the BioMEA™. It combines the most advanced MEA biochips with integrated electronics, and a novel user-friendly software interface. To move from prototype (result of the RMNT research project NEUROCOM) to manufactured product, a number of changes have been made. Here, we present a 256-channel MEA data acquisition system with integrated electronics (BioMEA™) allowing simultaneous recording and stimulation of neural networks for in vitro and in vivo applications. This integration is a first step towards an implantable device for BCI (Brain Computer Interface) studies and neural prosthesis.

Diversity of structures carrying the aac(6')-aph(2") gene in clinical Enterococcus faecalis and Enterococcus faecium strains isolated in Tunisia.

The diversity of structures carrying the aac(6')-aph(2") gene was studied in 46 high-level gentamicin-resistant Enterococcus faecalis and Enterococcus faecium clinical strains recovered in a Tunisian hospital during the period 2000-2003. The inclusion of the aac(6')-aph(2") gene within the Tn4001 composite element or in its truncated forms (lacking the IS256 at the right, the left or at both sides of the aac(6')-aph(2") gene) was investigated by PCR and sequencing. The aac(6')-aph(2") gene was included in the composite Tn4001 element in 19 of 34 high-level gentamicin-resistant E. faecalis strains (56%) and in 1 of 12 E. faecium strains (12%). A truncated form of Tn4001 lacking IS256 at the left-hand (in 10 E. faecalis and 8 E. faecium), at the right-hand (3 E. faecalis and 2 E. faecium) or at both sides of the aac(6')-aph(2") gene (in 2 E. faecalis and 1 E. faecium) was also detected in 26 of our enterococci. The transference by conjugation of the aac(6')-aph(2") gene, associated with other resistance genes, was demonstrated in seven of the high-level gentamicin-resistant E. faecalis strains.

Antibiotic resistance and mechanisms implicated in clinical enterococci in a Tunisian hospital.

Susceptibility testing for 15 antibiotics was performed in a series of 191 clinical enterococci recovered in a Tunisian Hospital during 2000-2003. Species detected were the following ones (number of isolates): E. faecalis (139), E. faecium (41), E. casseliflavus (5), E. gallinarum (3), E. avium (2) and E. hirae (1). The percentages of antibiotic resistance detected were as follows (E. faecalis/ E. faecium/ other species) : penicillin (0/ 73/ 9%), tetracycline (78/ 44/ 54%), chloramphenicol (52/ 29/ 27%), erythromycin (66/ 100/ 82%), spiramycin (84/ 83/ 64%), pristinamycin (100/ 0/ 73%), trimethoprim-sulfamethoxazole (88/ 78/ 91%), rifampicin (72/ 41/ 0%), vancomycin (0/ 0/ 36%), teicoplanin (0/ 0/ 0%), high-level-resistance for gentamicin (24/ 29/ 45%), streptomycin (34/ 56/ 55%) and kanamycin (41/ 68/ 55%). Increased vancomycin minimum inhibitory concentrations (MICs) were only detected in E. casseliflavus and E. gallinarum isolates (MIC range 8-24 microg/ml). The erm(B), catA, tet(M), aac(6')-aph(2''), aph(3')-IIIa, and ant(6)-Ia genes were detected in 91%, 32%, 86%, 98%, 100%, and 72% of the E. faecium and E. faecalis isolates resistant to erythromycin, chloramphenicol, tetracycline and high-level-resistant to gentamicin, kanamycin and streptomycin, respectively. A total of 20 unrelated pulsed-field-gel-electrophoresis patterns were found in the series of 46 high-level gentamicin-resistant E. faecalis and E. faecium isolates of this study.

Plasmachemical degradation of azo dyes by humid air plasma: Yellow Supranol 4 GL, Scarlet Red Nylosan F3 GL and industrial waste.

A recent non-thermal plasma technique (i.e., a gliding arc discharge which generates reactive species at atmospheric pressure) is tested for pollution abatement of dyes dispersed in synthetic solutions and industrial effluents. Yellow Supranol 4 GL (YS) and Scarlet Red Nylosan F3 GL (SRN) are toxic synthetic dyes widely used in the Algerian textile industry and frequently present in liquid wastes of manufacture plants. Classical removal treatment processes are not efficient enough, so that the presence of dyes in liquid effluents may cause serious environmental problems, in connection with reusing waste waters for irrigation. The degradation processes achieved by the oxidising species formed in the plasma are followed by UV/VIS spectroscopy and by chemical oxygen demand measurements. They are almost complete (i.e., 92.5% for YS and 90% for dilute SRN) and rapidly follow pseudo-first-order laws, with overall estimated rate constants 3 x 10(-4) and 4 x 10(-4)s-1 for YS and SRN, respectively. The degradation rate constant for the industrial mixture (i.e., k = 1.45 x 10(-3)s-1) is a mean value for two consecutive steps (210(-3) and 6 x 10(-5)s-1) measured at the absorption peaks of the major constituent dyes, YS and SRN.

Cellular responses to ErbB-2 overexpression in human mammary luminal epithelial cells: comparison of mRNA and protein expression.

Microarray analysis offers a powerful tool for studying the mechanisms of cellular transformation, although the correlation between mRNA and protein expression is largely unknown. In this study, a microarray analysis was performed to compare transcription in response to overexpression of the ErbB-2 receptor tyrosine kinase in a model mammary luminal epithelial cell system, and in response to the ErbB-specific growth factor heregulin beta1. We sought to validate mRNA changes by monitoring changes at the protein level using a parallel proteomics strategy, and report a surprisingly high correlation between transcription and translation for the subset of genes studied. We further characterised the identified targets and relate differential expression to changes in the biological properties of ErbB-2-overexpressing cells. We found differential regulation of several key cell cycle modulators, including cyclin D2, and downregulation of a large number of interferon-inducible genes, consistent with increased proliferation of the ErbB-2-overexpressing cells. Furthermore, differential expression of genes involved in extracellular matrix modelling and cellular adhesion was linked to altered adhesion of these cells. Finally, we provide evidence for enhanced autocrine activation of MAPK signalling and the AP-1 transcription complex. Together, we have identified changes that are likely to drive proliferation and anchorage-independent growth of ErbB-2- overexpressing cancer cells.

Impact of Heavy Metals on the Selective Phenotypical Markers of Pseudomonas aeruginosa.

The aim of this study was to characterize the impact of heavy metals on phenotypical markers of Pseudomonas aeruginosa. Twenty-two isolates of P. aeruginosa, either clinical (20) or secondary treated wastewater (2), were used to inoculate micro-ecosystems of sterile distilled water or secondary waste effluent in the presence of subminimal inhibitory concentrations of a variety of heavy metals commonly encountered in the aquatic naturally habitat (Ca2+, Co2+, Cr3+, Cu2+, Hg2+, Ni2+, Zn2+). Micro-ecosystems were exposed to visible light at laboratory temperature and individual strains were reisolated after a 1-, 3-, or 6-month period. The re-isolates (129) were characterized using hierarchical classification analysis in order to define affinities among variants of P. aeruginosa. Subsequently, discriminant analysis was used to detect eventual relationships among the different phenotypical markers studied. Results of the hierarchical classification, based on qualitative or quantitative approaches, showed clearly that incubation of P. aeruginosa in the presence of heavy metals altered the studied phenotypical markers, namely serotype, phage type, MIC of metals, and pyocin type. Discriminant analysis showed that the studied phenotypical markers could be classified into four clusters: C1 (L1 and L2 phage types, Hg tolerance and/or resistance, S2 serotype), C2 (P2 pyocin type, Cd tolerance and/or resistance, S1 serotype), C3 (Co and Cr tolerance and/or resistance) and C4 (P1 pyocin type, Ni, Zn, and Cu tolerance and/or resistance).

Infection of mice by a Toxoplasma gondii isolate from an AIDS patient: virulence and activation of hosts' immune responses are independent of parasite genotype.

Virulence of a Toxoplasma gondii isolate from an AIDS patient (designated as PTN) was compared with that of PLK, a variant of P-strain. Virulence was assessed in term of host survival upon inoculation in different strains of mice. All C57BL/6 mice died of acute toxoplasmosis by 7-10 days following intraperitoneal infection with 1 x 105 tachyzoites of PTN and 40% of BALB/c died on day 23 of infection, whereas 100% CBA/J infected with the same dose of PTN survived, as did outbred Swiss Webster mice. All C57BL/6, BALB/c, CBA/J, or Swiss Webster died of acute toxoplasmosis by 3-9 days postinfection upon inoculation with same dose of tachyzoites of the PLK strain. Further studies in CBA/J mice demonstrated that mice infected with PTN elicited a significantly higher lymphoproliferative response to crosslinked anti-CD3 mAb or Con A than PLK infected mice, and augmented production of TNFalpha, lower levels of nitrite and a higher number of NK cells. Genetical analysis indicated that both PLK and PTN strains of T. gondii are from type ll. Interestingly, being of the same genotype, the later showed less virulence upon inoculation in mice and had greater capacity to activate host immune system than the PLK strain.

[Evaluation of the clinical benefit of decompression hemicraniectomy in intracranial hypertension not controlled by medical treatment]. / Evaluation du bénéfice clinique de l'hémicraniectomie décompressive dans l'hypertension intracranienne non contrôlée par le traitement médical.

Through the findings in the literature on the basis of 9 personal cases, we review the indications and value of decompressive hemicraniectomy with plasty of the dura mater in cases of medically uncontrolled and decompensated intracranial hypertension. Seven patients had a pseudo-tumoral brain infarction. Five patients survived and their functional recovery is consistent with an autonomous daily life. Another patient with acute traumatic sub-dural haemorrhage died. The ninth patient had presuppurative encephalitis and recovered with no disability. At the time of surgery, all the patients were comatose with herniation of the mesencephalon (n = 3), uncal transtentorial herniation which was either unilateral (n = 4) or bilateral (n = 2). ICP was between 25 and 60 mmHg before the operation. After flap removal, ICP decreased by 15% and, after opening of the dura, it fell a further 70%. In 6 patients we were able to carry out continued post-operative monitoring of ICP, which stayed below 50% of initial values. Decompressive hemicraniectomy is an effective means of treating ICH caused by carotid cerebrovascular accidents with a high degree of edema, where mortality rises to 70-85% when only medical treatment is administered. No haemorrhagic complications, which can occur during hemispherectomies, were observed during decompression.