ROI-Based Compression Strategy of 3D MRI Brain Datasets for Wireless Communications

ObjectivesBecause of the large amount of medical imaging data, the transmission process becomes complicated in telemedicine applications. Thus, in order to adapt the data bit streams to the constraints related to the limitation of the bandwidths a reduction of the size of the data by compression of the images is essential. Despite the improvements in the field of compression, the transmission itself can also introduce errors. For this reason, it is important to develop an adequate strategy which will help reduce this volume of data without having to introduce some distortion and resist the errors introduced by the channel noise during transmission. Thus, in this paper, we propose a ROI-based coding strategy and unequal bit stream protection to meet this dual constraint.Material and methodsThe proposed ROI-based compression strategy with unequal bit stream protection is composed of three parts: the first one allows the extraction of the ROI region, the second one consists of a ROI-based coding and the third one allows an unequal protection of the ROI bit stream.First, the Regions Of Interest (ROI) are extracted by hierarchical segmentation of these regions according to a segmentation method based on the technique of Marker-based-watershed combined with the technique of active contours by level set. The resulting regions are selectively encoded by a 3D coder based on a shape adaptive discrete wavelet transform 3D-BISK, where the compression ratio of each region depends on its relevance in diagnosis. These obtained regions of interest are protected with an error-correcting code of Reed-Solomon type with a code rate that varies according to the relevance of the region by an unequal protection strategy (UEP).ResultsThe performance of the proposed compression scheme is evaluated in several ways. First, tests are performed to study the impact of errors on the different bit streams. In the first place, these tests are carried out in order to study the effect of the variation of the compression rates on the different bit streams. Secondly, different Reed Solomon error-correcting codes of different code rates are tested at different compression rates on a BSC channel. Finally, the performances of this coding strategy are compared with those of SPIHT 3D in the case of transmission on a BSC channel.ConclusionThe obtained results show that the proposed method is quite efficient in transmission time reduction. Therefore, our proposed scheme will reduce the volume of data without having to introduce some distortion and resist the errors introduced by the channel noise in the case of telemedicine.     

Extent of copper LDL oxidation depends on oxidation time and copper/LDL ratio: chemical characterization

The aim of our study was to determine, as a function of [Cu(2+)]/[LDL] ratios (0.5 and 0.05) and of oxidation phases, the extent of LDL oxidation by assessing the lipid and apo B oxidation products. The main results showed that: (i) kinetics of conjugated diene formation presented four phases for Cu(2+)/LDL ratio of 0.5 and two phases for [Cu(2+)]/[LDL] ratio of 0.05; (ii) oxidation product formation (cholesteryl ester and phosphatidylcholine hydroperoxides, apo B carbonyl groups) occurred early in the presence of endogenous antioxidants, under both copper oxidation conditions; (iii) apo B carbonylated fragments appeared when antioxidants were totally consumed at [Cu(2+)]/[LDL] ratio of 0.5; and (iv) antioxidant concentrations were stable, oxysterol formation was negligible, and no carbonylated fragment was detected at [Cu(2+)]/[LDL] ratio of 0.05. Depending on the copper/LDL ratio, oxidized LDL differ greatly in the nature of lipid peroxidation product and the degree of apo B fragmentation.     

Pharmacological blockage of serotonin biosynthesis and circadian changes in oxaliplatin toxicity in rats

This study investigates if the serotoninergic system plays a role in chronotoxic effects of the anticancer agent oxaliplatin (l-OHP). Four groups of female rats (120 in total) synchronized with light-dark (12 h:12 h) were treated with: (i) saline, (ii) para-chlorophenylalanine (pCPA, an inhibitor of serotonin biosynthesis: 300 mg/kg/d, i.p. for two consecutive days), (iii) l-OHP (23 mg/kg, i.v.) at three different dosing times, or (iv) both pCPA and l-OHP. The results show pCPA (ii) obliterates the circadian rhythm in plasma ACTH but not in corticosterone or leukocytes, and (iii) l-OHP exerts circadian time-dependent toxic effects (body weight loss, leukopenia, and intestinal lesions) with greatest toxicity coinciding with treatment at the end of the nocturnal activity span (P < 0.05). In rats whose serotonin biosynthesis was blocked (iv), the circadian rhythms in the toxic effects of l-OHP and in ACTH were obliterated, while the rhythms in corticosterone and leukocytes persisted.     

Leishmania infantum species-specific kDNA probes: isolation and evaluation

The study refers to the isolation of specific DNA probes to the parasite species Leishmania (L) infantum according to different strategies using recombinant minicircles isolated from L. infantum kinetoplast DNAs. A first probe was identified following a classical procedure. One mini-circle selected for strong reactivity to L. infantum total DNA was used to identify specific subfragments to this species among which the 95bp fragment, 3B8HaeIII-2 was selected. For the obtention of the second probe, a strategy based on sequential screenings for specificity and sensitivity was applied. This allowed identification of a set of minicircles showing an increased specificity to L. infantum as compared to other species, and an increased sensitivity of reaction as compared to the other minicircles. Subclonings and screenings allowed a final selection of a 137bp-minicircle fragment: 3E9HaeIII-12. Reactivities of the 2 probes were assessed on a panel of total DNAs and promastigotes from 74 isolates pertaining to 9 species encountered in the Old World. Parasites isolated in Tunisia from different foci, different hosts after different transmission seasons were included. Hybridizations have shown the exquisite specificity of these probes to L. infantum in this country. Probe 3E9HaeIII-12 was found to be the more sensitive where down to 10 ng of total DNA and 10(3) promastigotes could be detected. From this study and as compared to data provided in the literature, the second procedure allowed at least 10-fold increase in sensitivity.     

Effect of Some Variables on theIn VivoDetermination of Scorpion and Viper Venom Toxicities

An adequate assessment of scorpion and snake venom LD50 is an important step for accurate evaluation of antivenom sera potencies and the optimization of serotherapy. The LD50 variation of Tunisian scorpion (Androctonus australis garzonii: Aag and Buthus occitanus tunetanus: Bot) venoms with body weight, sex and strain (Swiss or C57BI/6) of mice used, the route of venom injection, the venom-milking procedures (manually or electrically) and the venom batches have been studied over a 7-year period (1990-1996). Aag venom is 3-4 times more toxic than Bot venom. However for both venoms, the LD50 determined in C57BI/6 mice, in small body weight animal or by intraperitoneal route were respectively significantly lower than those determined in Swiss mice, in high body weight or by subcutaneous route. Significant LD50 variations (25-50%) were also seen from one electrically prepared batch to another. A good correlation (r = 0.982) was observed between the concentrations of the crude venom toxic fraction determined by ELISA and LD50 values when assessed in vivo. The LD50 variation of Tunisian viper (Cerastes cerastes: Cc and Vipera lebetina: VI) venoms with the strain (Swiss or BALB/c), sex and body weight of mice used, the season and the year of venom milking were also investigated over a 3-year period (1990-1992). No significant LD50 variations were observed with the mouse strain, the sex or the season of venom milking. However, LD50 varies significantly with the year of the venom collection and the body weight of mice used. Furthermore, SDS-PAGE analysis shows annual variation for VI venom composition where no such variations were observed for Cc venom. These results stress the need either for the standardization of the venom LD50 evaluation or of the venom quality used for the development of an efficient antivenom.     

Effect of Some Variables on theIn VivoDetermination of Scorpion and Viper Venom Toxicities

An adequate assessment of scorpion and snake venom LD₅₀is an important step for accurate evaluation of antivenom sera potencies and the optimization of serotherapy. The LD₅₀variation of Tunisian scorpion (Androctonus australis garzonii: Aag andButhus occitanus tunetanus: Bot) venoms with body weight, sex and strain (Swiss or C57Bl/6) of mice used, the route of venom injection, the venom-milking procedures (manually or electrically) and the venom batches have been studied over a 7-year period (1990–1996). Aag venom is 3–4 times more toxic than Bot venom. However for both venoms, the LD₅₀determined in C57Bl/6 mice, in small body weight animal or by intraperitoneal route were respectively significantly lower than those determined in Swiss mice, in high body weight or by subcutaneous route. Significant LD₅₀variations (25–50%) were also seen from one electrically prepared batch to another. A good correlation (r=0·982) was observed between the concentrations of the crude venom toxic fraction determined by ELISA and LD₅₀values when assessedin vivo.The LD₅₀variation of Tunisian viper (Cerastes cerastes: Cc andVipera lebetina: VI) venoms with the strain (Swiss or BALB/c), sex and body weight of mice used, the season and the year of venom milking were also investigated over a 3-year period (1990–1992). No significant LD₅₀variations were observed with the mouse strain, the sex or the season of venom milking. However, LD₅₀varies significantly with the year of the venom collection and the body weight of mice used. Furthermore, SDS–PAGE analysis shows annual variation for VI venom composition where no such variations were observed for Cc venom. These results stress the need either for the standardization of the venom LD₅₀evaluation or the venom quality used for the development of an efficient antivenom.     

Intraperitoneal Echinococcus multilocularis infection in mice modulates peritoneal CD4+ and CD8+ regulatory T cell development

Intraperitoneal proliferation of the metacestode stage of Echinococcus multilocularis in experimentally infected mice is followed by an impaired host immune response favoring parasite survival. We here demonstrate that infection in chronically infected mice was associated with a 3-fold increase of the percentages of CD4+ and CD8+ peritoneal T (pT) cells compared to uninfected controls. pT cells of infected mice expressed high levels of IL-4 mRNA, while only low amounts of IFN-γ mRNA were detected, suggesting that a Th2-biased immune response predominated the late stage of disease. Peritoneal dendritic cells from infected mice (AE-pDCs) expressed high levels of TGF-β mRNA and very low levels of IL-10 and IL-12 (p40) mRNA, and the expression of surface markers for DC-maturation such as MHC class II (Ia) molecules, CD80, CD86 and CD40 was down-regulated. In contrast to pDCs from non-infected mice, AE-pDCs did not enhance Concanavalin A (ConA)-induced proliferation when added to CD4+ pT and CD8+ pT cells of infected and non-infected mice, respectively. In addition, in the presence of a constant number of pDCs from non-infected mice, the proliferation of CD4+ pT cells obtained from infected animals to stimulation with ConA was lower when compared to the responses of CD4+ pT cells obtained from non-infected mice. This indicated that regulatory T cells (Treg) may interfere in the complex immunological host response to infection. Indeed, a subpopulation of regulatory CD4+ CD25+ pT cells isolated from E. multilocularis-infected mice reduced ConA-driven proliferation of CD4+ pT cells. The high expression levels of Foxp3 mRNA by CD4+ and CD8+ pT cells suggested that subpopulations of regulatory CD4+ Foxp3+ and CD8+ Foxp3+ T cells were involved in modulating the immune responses within the peritoneal cavity of E. multilocularis-infected mice.     

Bacterial community diversity assessment in municipal solid waste compost amended soil using DGGE and ARISA fingerprinting methods

Bacterial community structure and diversity of Tunisian agricultural soil treated with different amounts of municipal solid waste compost (MSWC) and other fertilizers were studied using DGGE and ARISA fingerprinting methods. Sequence analysis of dominant DGGE bands revealed the presence of three major clusters, Cytophaga/Flexibacter/Bacteroides (CFB) group, Proteobacteria and Acidobacteria group. Using ARISA profiles, dominant populations were assigned to low and high GC Gram positive bacteria, Cyanobacteria, Spirochetes and Cytophagales. The two methods revealed the absence of significant bacterial community shifts related to the different MSWC applications. Moreover, indigenous bacterial population of the used loam-clayey soil was observed to limit proliferation and survival of Proteobacteria, initially dominant in MSWC and farmyard manure. Effectiveness of the two methods for soil bacterial community studying was shown. While DGGE was more accurate for bacterial identification, ARISA was more practical for handling and rapid estimation of dominant bacteria.     

Broad-range PCR,cloning and sequencing of the full 16S rRNA gene for detection of bacterial DNA in synovial fluid samples of Tunisian patients with reactive and undifferentiated arthritis

Introduction

Broad-range rDNA PCR provides an alternative, cultivation-independent approach for identifying bacterial DNA in reactive and other form of arthritis. The aim of this study was to use broad-range rDNA PCR targeting the 16S rRNA gene in patients with reactive and other forms of arthritis and to screen for the presence of DNA from any given bacterial species in synovial fluid (SF) samples.

Methods

We examined the SF samples from a total of 27 patients consisting of patients with reactive arthritis (ReA) (n = 5), undifferentiated arthritis (UA) (n = 9), rheumatoid arthritis (n = 7), and osteoarthritis (n = 6) of which the latter two were used as controls. Using broad-range bacterial PCR amplifying a 1400 bp fragment from the 16S rRNA gene, we identified and sequenced at least 24 clones from each SF sample. To identify the corresponding bacteria, DNA sequences were compared to the EMBL (European Molecular Biology Laboratory) database.

Results

Bacterial DNA was identified in 20 of the 27 SF samples (74, 10%). Analysis of a large number of sequences revealed the presence of DNA from more than one single bacterial species in the SF of all patients studied. The nearly complete sequences of the 1400 bp were obtained for most of the detected species. DNA of bacterial species including Shigella species, Escherichia species, and other coli-form bacteria as well as opportunistic pathogens such as Stenotrophomonas maltophilia and Achromobacter xylosoxidans were shared in all arthritis patients. Among pathogens described to trigger ReA, DNA from Shigella sonnei was found in ReA and UA patients. We also detected DNA from rarely occurring human pathogens such as Aranicola species and Pantoea ananatis. We also found DNA from bacteria so far not described in human infections such as Bacillus niacini, Paenibacillus humicus, Diaphorobacter species and uncultured bacterium genera incertae sedis OP10.

Conclusions

Broad-range PCR followed by cloning and sequencing the entire 16S rDNA, allowed the identification of the bacterial DNA environment in the SF samples of arthritic patients. We found a wide spectrum of bacteria including those known to be involved in ReA and others not previously associated with arthritis.