Relationship between impaired apoptosis of lymphocytes and distribution of dendritic cells in peripheral blood and synovial fluid of children with juvenile idiopathic arthritis

INTRODUCTION: The pathogenesis of juvenile idiopathic arthritis (JIA) is not fully understood. Recently the present authors described disturbed apoptosis of JIA lymphocytes in both peripheral blood (PB) and synovial fluid (SF) as well as an abnormal distribution of blood dendritic cells (BDCs) between the PB and SF in this disease. Possible relationships between these events during the development of JIA process are assessed here. MATERIALS AND METHODS: Lymphocyte apoptosis and BDC counts were assessed in the PB and SF of untreated JIA children. Lymphocyte apoptosis was analyzed by the Annexin-V/propydium iodide assay. Total DC (TDC) number was based on the sum of three BDC subpopulations determined using a panel of monoclonal antibodies against BDC antigens (BDCA): myeloid type 1 (mDC1, BDCA-1(+)/HLA-DR(+)/CD19(-)), myeloid type 2 (mDC2, BDCA-3(+)/HLA-DR(+)/CD14(-)), and plasmacytoid (pDC, BDCA-2(+)/HLA-DR(+)/CD123(+)). Cells were enumerated by the flow cytometric "single-platform" method. The concentration of tumor necrosis factor (TNF)-alpha and the distribution of particular lymphocyte subtypes in both PB and SF were also investigated. RESULTS: There was significant positive correlation between apoptosis of PB lymphocytes and SF TDC count (p=0.002) as well as SF TNF-alpha concentration (p=0.007). SF TNF-alpha levels also correlated with SF TDC count (p=0.003). Moreover, JIA SF was distinctly enriched with CD4+ and CD8+ T lymphocytes and included CD4(+)/CD25(high) cells as well. There was significant positive correlation between the number of CD4(+)/CD25(high) cells and SF JIA BDC count (p=0.015). CONCLUSIONS: These data suggest a possible link between impaired apoptosis of PB/SF lymphocytes and increased recruitment of PB BDCs to SF and other elements of the immune system in JIA, including regulatory CD4+/CD25high cells.     

Genetic susceptibility to visceral leishmaniasis in The Sudan: linkage and association with IL4 and IFNGR1

Longitudinal studies in Sudan show ethnic differences in incidence and clinical phenotypes associated with Leishmania donovani. Immunologically, bias in type 1 vs type 2 cytokine responses is important. To determine whether polymorphisms at IL4/IL9 or IFNGR1 contribute to susceptibility, we examined 59 multicase families of visceral leishmaniasis (VL) with/without post Kala-azar dermal leishmaniasis (PKDL). Multipoint nonparametric analysis (Allegro) linked IL4/IL9 to VL per se (P=0.002). Transmission disequilibrium testing with robust variance estimates confirmed association in the presence of linkage between VL per se and IL4 (P=0.008) but not IL9. Stepwise logistic regression analysis showed both IL4RP2 and IL4RP1 markers contributed significantly to the association, suggesting a common disease-associated haplotype. In contrast, IFNGR1 was linked (P=0.031) and associated (P=0.007) to PKDL but not VL or VL per se. Hence, polymorphism in a type 2 cytokine gene influences underlying susceptibility to VL, whereas IFNGR1 is specifically related to susceptibility to PKDL.     

Role of heat-shock factor 2 in cerebral cortex formation and as a regulator of p35 expression

Heat-shock factors (HSFs) are associated with multiple developmental processes, but their mechanisms of action in these processes remain largely enigmatic. Hsf2-null mice display gametogenesis defects and brain abnormalities characterized by enlarged ventricles. Here, we show that Hsf2-/- cerebral cortex displays mispositioning of neurons of superficial layers. HSF2 deficiency resulted in a reduced number of radial glia fibers, the architectural guides for migrating neurons, and of Cajal-Retzius cells, which secrete the positioning signal Reelin. Therefore, we focused on the radial migration signaling pathways. The levels of Reelin and Dab1 tyrosine phosphorylation were reduced, suggesting that the Reelin cascade is affected in Hsf2-/- cortices. The expression of p35, an activator of cyclin-dependent kinase 5 (Cdk5), essential for radial migration, was dependent on the amount of HSF2 in gain- and loss-of-function systems. p39, another Cdk5 activator, displayed reduced mRNA levels in Hsf2-/- cortices, which, together with the lowered p35 levels, decreased Cdk5 activity. We demonstrate in vivo binding of HSF2 to the p35 promoter and thereby identify p35 as the first target gene for HSF2 in cortical development. In conclusion, HSF2 affects cellular populations that assist in radial migration and directly regulates the expression of p35, a crucial actor of radial neuronal migration.     

Fluorescence in situ hybridization studies using BAC clones of the EVI1 locus in hematological malignancies with 3q rearrangements

Chromosomal rearrangements involving 3q26 are a recurrent aberration in malignant myeloid disorders. Several of these rearrangements involve the EVI1 oncogene or its surrounding sequences and are associated with a poor prognosis. Fluorescence in situ hybridization (FISH) studies using bacterial artificial chromosome (BAC) clones were conducted to determine whether the EVI1 locus was rearranged in nine patients with hematological malignancies carrying 3q abnormalities. A dual-color probe was constructed with nine BACs; centromeric clones covering 1 Mb and including the EVI1 gene were labeled with a red fluorescent dye and telomeric clones covering 1 Mb were labeled with a green fluorescent dye. Two patients showed normal copies of the EVI1 locus, four patients showed one EVI1 locus rearranged (in all of them the breakpoint on 3q26 was telomeric to EVI1), one patient showed one copy of the EVI1 locus translocated to another chromosome, one patient showed one copy of the EVI1 locus rearranged and the other copy translocated, and one patient showed one extra copy of the EVI1 locus. In four cases, FISH studies using the EVI1 clones detected different 3q abnormalities not previously found by conventional cytogenetics. FISH analysis with BAC clones was a useful tool for identifying the chromosome breakpoints affecting the EVI1 locus in patients with 3q26 rearrangements.     

Performance enhancement for audio-visual speaker identification using dynamic facial muscle model

Science of human identification using physiological characteristics or biometry has been of great concern in security systems. However, robust multimodal identification systems based on audio-visual information has not been thoroughly investigated yet. Therefore, the aim of this work to propose a model-based feature extraction method which employs physiological characteristics of facial muscles producing lip movements. This approach adopts the intrinsic properties of muscles such as viscosity, elasticity, and mass which are extracted from the dynamic lip model. These parameters are exclusively dependent on the neuro-muscular properties of speaker; consequently, imitation of valid speakers could be reduced to a large extent. These parameters are applied to a hidden Markov model (HMM) audio-visual identification system. In this work, a combination of audio and video features has been employed by adopting a multistream pseudo-synchronized HMM training method. Noise robust audio features such as Mel-frequency cepstral coefficients (MFCC), spectral subtraction (SS), and relative spectra perceptual linear prediction (J-RASTA-PLP) have been used to evaluate the performance of the multimodal system once efficient audio feature extraction methods have been utilized. The superior performance of the proposed system is demonstrated on a large multispeaker database of continuously spoken digits, along with a sentence that is phonetically rich. To evaluate the robustness of algorithms, some experiments were performed on genetically identical twins. Furthermore, changes in speaker voice were simulated with drug inhalation tests. In 3 dB signal to noise ratio (SNR), the dynamic muscle model improved the identification rate of the audio-visual system from 91 to 98%. Results on identical twins revealed that there was an apparent improvement on the performance for the dynamic muscle model-based system, in which the identification rate of the audio-visual system was enhanced from 87 to 96%.     

Prevalence of aminoglycoside-modifying enzymes genes among isolates of Enterococcus faecalis and Enterococcus faecium in Iran

Disks containing 120 microg of gentamicin were used to detect high-level gentamicin-resistant phenotype (HLGR) among isolates of Enterococcus faecalis (n = 79) and E. faecium (n = 35). These isolates were collected from three hospitals in Tehran during 2002-2004. The macrobroth dilution assay was then used to determine the minimum inhibitory concentration (MIC) of gentamicin. The susceptibility of isolates against amikacin, netilmicin, tobramycin, and kanamycin were also determined by Kirby-Bauer method. All isolates were subjected to polymerase chain reaction (PCR) assays targeting aminoglycoside modifying enzyme (AMEs) genes including aac(6 ')-aph(2 "), aph(2 ")-Ib, aph(2 ")-Ic, aph(2 ")-Ia, aph(2 ")-Id, aph(3 ')-IIIa, and ant(4 ')-Ia. Fifty-nine isolates (52%) showed HLGR phenotype. All isolates with HLGR phenotype and those showing 64 < MIC < 500 microg/ml contained aac(6 ')-aph(2 "). The aph(3 ')-IIIa was found in 61% of the isolates with HLGR phenotypes and in 65% of isolates with MIC < 500. Coexistence of aac(6 ')-aph(2 ") and aph(3 ')-IIIa gene among HLGR isolates of E. faecalis and E. faecium were 60% and 65%, respectively. The gene aph(2 ")-Ic was amplified in two isolates of E. faecium. The results of PCR for aph(2 ")-Id, ant(4 ')-Ia and aph(2 ")-Ib genes were negative. The aac(6 ')-aph(2 ") was the most frequent gene encoding resistance to gentamicin and other aminoglycosides followed by aph(3 ')-IIIa. Isolates lacking these genes were susceptible to all aminoglyocosides tested in this study.     

Deblurring of breathing motion artifacts in thoracic PET images by deconvolution methods

In FDG-PET imaging of thoracic tumors, blurring due to breathing motion often significantly degrades the quality of the observed image, which then obscures the tumor boundary. We demonstrate a deblurring technique that combines patient-specific motion estimates of tissue trajectories with image deconvolution techniques, thereby partially eliminating breathing-motion induced artifacts. Two data sets were used to evaluate the methodology including mobile phantoms and clinical images. The clinical images consist of PET/CT co-registered images of patients diagnosed with lung cancer. A breathing motion model was used to locally estimate the location-dependent tissue location probability function (TLP) due to breathing. The deconvolution process is carried by an expectation-maximization (EM) iterative algorithm using the motion-based TLP. Several methods were used to improve the robustness of the deblurring process by mitigating noise amplification and compensating for motion estimate uncertainties. The mobile phantom study with controlled settings demonstrated significant reduction in underestimation error of concentration in high activity case without significant superiority between the different applied methods. In case of medium activity concentration (moderate noise levels), less improvement was reported (10%-15% reduction in underestimation error relative to 15%-20% reduction in high concentration). Residual denoising using wavelets offered the best performance for this case. In the clinical data case, the image spatial resolution was significantly improved, especially in the direction of greatest motion (cranio-caudal). The EM algorithm converged within 15 and 5 iterations in the large and small tumor cases, respectively. A compromise between a figure-of-merit and entropy minimization was suggested as a stopping criterion. Regularization techniques such as wavelets and Bayesian methods provided further refinement by suppressing noise amplification. Our initial results show that the proposed method provides a feasible framework for improving PET thoracic images, without the need for gated/4-D PET imaging, when 4-D CT is available to estimate tumor motion.     

In vitro and in vivo degradation of oxidized acetyl- and ethyl-cellulose sponges

The objective of this study was to assess the in vitro and in vivo degradation properties of macroporous sponges composed of oxidized acetyl-cellulose (AC; 45.000 Mw) and ethyl-cellulose (EC; 50.000 Mw). The sponges were constructed by solvent-casting and particulate-leaching technique using a polymer concentration of 2.5 and 5.0% (w:v), and periodate oxidation. The resulting sponges were: AC2.5, AC5.0, EC2.5 and EC5.0. While AC sponges exhibited a gradual degradation overtime, EC sponges had a very slow in vitro mass loss. In general, sponges made up of 2.5% (w:v) polymer content degraded faster than the ones with 5.0% (w:v). The sponges degraded faster at pH 5.0, compared to pH 6.0 and 7.4 conditions. About 60%, 44% and 31% of dry mass loss was determined for AC2.5 sponges after 60 weeks at pH 5.0, pH 6.0 and pH 7.4 conditions, respectively; thus, ca. 21%, 13% and 12% of dry mass loss from EC2.5 sponges was observed at the same pH conditions, in the same order. The in vivo degradation studies were performed on Wistar rats (n = 24) for a duration of 60 weeks. In general, all sponge implants were well-tolerated by the subjects. While granulation tissue or fibrotic capsule was not formed around the sponges, neovascularization was observed. AC and EC sponges demonstrated an in vivo degradation behavior quite similar to that observed for the in vitro study conducted at pH 5.0 conditions. Histomorphometric analysis revealed that the in vivo degradation of AC2.5 and EC2.5 after 60 weeks was about 47% and 18%, respectively. The results indicate that oxidized acetyl cellulose may be considered as a partially degradable scaffold material for tissue engineering applications.     

Preimplantation genetic diagnosis

Pre-Implantation genetic diagnosis is available to couples at risk of conceiving a pregnancy affected with a known genetic disorder. Assisted reproductive techniques are used in combination with micromolecular diagnostic technologies to recognise at-risk embryos with pathogenic genetic variants at the pre-implantation stage using polar body, blastomere or trophectoderm biopsy. This review will discuss the varying genetic disorders diagnosed by Pre-Implantation Genetic Diagnosis, as well as the ethical, legal and safety implications of the process. Pioneering advances in molecular biology and cytogenomics have been utilised to expand the spectrum of genetic disorders detected.