Clinical Evaluation of Compression Ratios using JPEG2000 on Computed Radiography Chest Images

The efficient compression of radiographic images is of importance for improved storage and network utilization in support of picture archiving and communication systems (PACS) applications. The DICOM Working Group 4 adopted JPEG2000 as an additional compression standard in Supplement 61 over the existing JPEG. The wavelet-based JPEG2000 can achieve higher compression ratios with less distortion than the Discrete Cosine Transform (DCT)-based JPEG algorithm. However, the degradation of JPEG2000-compressed computed radiography (CR) chest images has not been tested comprehensively clinically. The authors evaluated the diagnostic quality of JPEG2000-compressed CR chest images with compression ratios from 5:1 to 200:1. An ROC (receiver operating characteristic analysis) and t test were performed to ascertain clinical performance using the JPEG2000-compressed images. The authors found that compression ratios as high as 20:1 can be utilized without affecting lesion detectability. Significant differences between the original and the compressed CR images were not recognized up to compression ratio of 50:1 within a confidence level of 99%.     

Cytokine responses in mice infected with<Emphasis Type="Italic"> Clonorchis sinensis</Emphasis>

FVB and BALB/c mice show different morbidity, development of Clonorchis sinensis, and pathological changes following C. sinensis infection. FVB mice are susceptible and BALB/c mice are relatively more resistant to C. sinensis infection. To investigate the relationship between cytokine reaction and susceptibility to C. sinensis infection in FVB and BALB/c mice, we described both the patterns and kinetics of Th1 cytokines and Th2 cytokines in spleen cell culture. Interleukin (IL)-4 and IL-10 cytokine production in the culture supernatants of the concanavalin-A-stimulated spleen cells increased at 2–3 weeks post-infection in both strains. IL-5 production increased between 2 and 5 weeks post-infection in both strains, and reached a peak level at 2 weeks post-infection in BALB/c mice and 4 weeks post-infection in FVB mice. In contrast, gamma interferon (IFN-) production decreased between 2 and 4 weeks in both strains. IL-2 production increased slightly in BALB/c mice following infection, but was unchanged in FVB mice. IL-4 production over preinfection levels was significantly higher in FVB mice, whereas IFN-, IL-2, and IL-10 production were significantly higher in BALB/c mice. The levels of serum immunoglobulin E (IgE) and blood eosinophils in both mouse strains significantly increased between 3 and 6 weeks postinfection. Serum IgE levels were significantly higher in FVB mice than in BALB/c mice. The results of this study suggest that susceptibility to C. sinensis infection is associated with Th2 cytokine production, especially IL-4 which is predominant in relatively susceptible FVB mice.     

Nonvascular interventions of the urinary tract

Nonvascular intervention of the urinary tract is a well-established uroradiologic subspecialty, which is more important for avoiding invasive open surgery in the age of rising demand about the value of less invasive treatment. Various kinds of nonvascular intervention are recently performed under image-guidance and are as follows: percutaneous nephrostomy, percutaneous nephrostolithotomy, percutaneous dilatation of the urinary tract, sclerotherapy for renal cysts, percutaneous catheter drainage, percutaneous foreign body retrieval and biopsy. Percutaneous nephrostomy is a basic technique to provide a direct access to urinary tract, which makes it possible to perform other interventional procedures. Although nonvascular intervention may produce some complications, it is generally considered to be less invasive than open surgery and has advantages such as short hospital stay, early return to normal life and therefore economic savings. This review is described to help clinicians easily understand the procedures, indications, techniques, and complications with figures of cases the authors experienced.     

Nerve injury alters profile of receptor-mediated Ca2+ channel modulation in vagal afferent neurons of rat nodose ganglia

Although nerve injury is known to up- and down-regulate some metabotropic receptors in vagal afferent neurons of the nodose ganglia (NG), the functional significance has not been elucidated. In the present study, thus, we examined whether nerve injury affected receptor-mediated Ca2+ channel modulation in the NG neurons. In this regard, unilateral vagotomy was performed using male Sprague-Dawley rats. One week after vagotomy, Ca2+ currents were recorded using the whole-cell variant of patch-clamp technique in enzymatically dissociated NG neurons. In sham controls, norepinephrine (NE)-induced Ca2+ current inhibition was negligible. Following vagotomy, however, the NE responses were dramatically increased. This phenomenon was in accordance with up-regulation of alpha2A/B-adrenergic receptor mRNAs as quantified using real-time RT-PCR analysis. In addition, neuropeptide Y (NPY) and prostaglandin E2 responses were moderately augmented in vagotomized NG neurons. The altered NPY response appears to be caused by up-regulation of Y2 receptors negatively coupled to Ca2+ channels. In contrast, nerve injury significantly suppressed opioid (tested with DAMGO)-induced Ca2+ current inhibition with down-regulation of micro-receptors. Taken together, these results demonstrated for the first time that the profile of neurotransmitter-induced Ca2+ channel modulation is significantly altered in the NG neurons under pathophysiological state of nerve injury.     

Altered expression of G1 regulatory proteins in human soft tissue sarcomas

CONTEXT: Soft tissue sarcomas constitute a heterogeneous group of tumors for which tumorigenesis is not fully understood. Altered cell-cycle regulation may underlie the development and/or progression of human malignancies. However, data concerning the occurrence of cell-cycle aberrations in soft tissue sarcomas are very limited. OBJECTIVES: To detect the abnormal features of cell-cycle regulatory proteins in soft tissue sarcomas and to determine the potential role of these proteins in clinical behavior. DESIGN: The p53 and Rb-cyclin D pathways were investigated by immunohistochemical studies of p53, mdm2, pRb, p16, cyclin D1, and cdk4 proteins, respectively. RESULTS: Of the 67 sarcomas analyzed, nuclear accumulation of p53 was detected in 25 samples (37%), and overexpression of mdm2 was found in 16 samples (24%). Both p53 and mdm2 expression correlated with tumor grade. Abnormalities involving the Rb-cyclin D pathway were identified in all of the tumors by the altered expression of either pRb (72%) or p16 (94%). Fourteen (21%) and 64 (96%) cases demonstrated cyclin D1 or cdk4 expression, respectively. Overexpression of cyclin D1 showed an association with pRb and p53. There was no correlation between pRb, p16, cyclin D1, or cdk4 and tumor grade or relapse. CONCLUSION: Disturbance in the cell-cycle regulatory system involving the p53 pathway and the Rb-cyclin D pathway is relatively frequent in soft tissue sarcomas and may be a contributing factor in the tumorigenesis of these tumors. The alterations in the Rb-cyclin D pathway probably constitute an early event, whereas the abnormalities in the p53 pathway seem to be involved in tumor progression. It is noteworthy that cyclin D1 may play a key role in linking both pathways.     

Monophosphoryl lipid A (MPL) upregulates major histocompatibility complex (MHC) class I expression by increasing interferon-gamma (IFN-gamma)

Tumor immunity is primarily mediated by cells as CD8+ cytotoxic T lymphocytes (CTL) recognize tumor antigen by MHC class I molecules. But most tumors are associated with a decreased expression of MHC class I to escape the antitumor immunity of the host. Our previous data have demonstrated that MPL has an antitumor effect on metastatic lung cancer of B16 melanoma with enhancing cytotoxicity due to increase of IFN-gamma and IL-2, and decrease of IL-4, which indicates the stimulation of type 1 helper T cells (Th1). To determine the effects of MPL, IFN-gamma, TNF-alpha, and IL-1 alpha on MHC class I expression of B16 melanoma cells, we evaluated the expression of MHC class I molecules with treatments of MPL, IFN-gamma, TNF-alpha, and IL-1 alpha by flow cytometry. The supernatant of MPL-treated spleen cells in vitro upregulated the expression of MHC class I molecules of B16 melanoma cells compared to the control supernatant of spleen cells. The MHC class I expression of B16 melanoma cells treated with IFN-gamma, but not TNF-alpha or IL-1 alpha, increased in a time-dependent manner. In conclusion, MPL upregulated MHC class I expression of B16 melanoma cells by activating spleen cells via IFN-gamma. These data suggest that increased IFN-gamma by MPL is responsible for the upregulation of MHC class I expression to augment cytotoxicity. Therefore, we suggest that MPL could play an important role in immunotherapy.     

Multiple imputation technique applied to appropriateness ratings in cataract surgery

Missing data such as appropriateness ratings in clinical research are a common problem and this often yields a biased result. This paper aims to introduce the multiple imputation method to handle missing data in clinical research and to suggest that the multiple imputation technique can give more accurate estimates than those of a complete-case analysis. The idea of multiple imputation is that each missing value is replaced with more than one plausible value. The appropriateness method was developed as a pragmatic solution to problem of trying to assess "appropriate" surgical and medical procedures for patients. Cataract surgery was selected as one of four procedures that were evaluated as a part of the Clinical Appropriateness Initiative. We created mild to high missing rates of 10%, 30% and 50% and compared the performance of logistic regression in cataract surgery. We treated the coefficients in the original data as true parameters and compared them with the other results. In the mild missing rate (10%), the deviation from the true coefficients was quite small and ignorable. After removing the missing data, the complete-case analysis did not reveal any serious bias. However, as the missing rate increased, the bias was not ignorable and it distorted the result. This simulation study suggests that a multiple imputation technique can give more accurate estimates than those of a complete-case analysis, especially for moderate to high missing rates (30 - 50%). In addition, the multiple imputation technique yields better accuracy than a single imputation technique. Therefore, multiple imputation is useful and efficient for a situation in clinical research where there is large amounts of missing data.     

Three-dimensional forward solver and its performance analysis for magnetic resonance electrical impedance tomography (MREIT) using recessed electrodes

In magnetic resonance electrical impedance tomography (MREIT), we try to reconstruct a cross-sectional resistivity (or conductivity) image of a subject. When we inject a current through surface electrodes, it generates a magnetic field. Using a magnetic resonance imaging (MRI) scanner, we can obtain the induced magnetic flux density from MR phase images of the subject. We use recessed electrodes to avoid undesirable artefacts near electrodes in measuring magnetic flux densities. An MREIT image reconstruction algorithm produces cross-sectional resistivity images utilizing the measured internal magnetic flux density in addition to boundary voltage data. In order to develop such an image reconstruction algorithm, we need a three-dimensional forward solver. Given injection currents as boundary conditions, the forward solver described in this paper computes voltage and current density distributions using the finite element method (FEM). Then, it calculates the magnetic flux density within the subject using the Biot-Savart law and FEM. The performance of the forward solver is analysed and found to be enough for use in MREIT for resistivity image reconstructions and also experimental designs and validations. The forward solver may find other applications where one needs to compute voltage, current density and magnetic flux density distributions all within a volume conductor.     

Age-dependent changes of gene expression in the Drosophila head

Previous gene expression profiling studies in Drosophila have provided clues for understanding the aging process at the gene expression level. For a detailed understanding, studies of specific regions of the body are necessary. We therefore employed microarray analysis to examine gene expression changes in the Drosophila head during aging. Six hundred and eighty-four of the 5405 genes present in the microarray showed significant age-dependent changes as determined by significance analysis of microarray (SAM) (q < 0.05). The biological significance of the changes was analyzed using the gene annotations provided by the Gene Ontology Consortium. Major changes involved genes affecting energy metabolism (proton transport, energy pathways, oxidative phosphorylation) and neuronal function, especially responses to light. Genes involved in protein catabolism and several other metabolic processes also showed age-dependent changes. Most of the changes were reductions in gene expression and occurred before day 13 of adult life. After day 13, the age-dependent gene expression changes were relatively smaller than earlier life. Interestingly, the two biological processes of major gene expression changes are related to the two known environmental changes that increase life span in Drosophila: caloric restriction and light reduction. Our findings suggest that light signaling and energy metabolism may be important biological processes affected by aging and be interesting targets for the further investigation related to the longevity in Drosophila.     

Surface immunoglobulins mediate efficient transport of antigen to lysosomal compartments resulting in enhanced specific antigen presentation by B cells

A BCL₁ immunoglobulin (Ig) transfectant, expressing wild-type surface (s)IgM with the TEPC-15 idiotype (T15-Id) and anti-phosphorylcholine (PC) specificity, was previously shown to present PC-conjugated hen egg-white lysozyme (PC-HEL) to a HEL-specific T cell hybridoma at a lower antigen (Ag) concentration than that required for native HEL. Two variant Ig transfectants, expressing T15-Id sIgM with substitutions either in the entire spacer, transmembrane (TM) domain and cytoplasmic tail (B186 variant) or in the NH₂-terminal third of TM domain only (TM2 variant), failed to display this sIgM-mediated, enhanced presentation of PC-HEL at low concentrations. However, prolonged treatment with anti-T15-Id monoclonal antibody (mAb) led to a reduction of surface expression of the T15-Id sIgM in the wild-type and TM2 variant, but not in the B186 variant sIgM transfectants. Treatment with anti-T15-Id mAb also resulted in an increased intracellular accumulation of T15-Id sIgM in the wild-type transfectant, but not in the B186 variant. Subcellular fractionation analysis revealed that the ligands bound to the T15-Id sIgM are not efficiently transported to the dense lysosomal compartments in both B186 and TM2 transfectants, as compared to the wild-type sIgM transfectant. A significant increase in tyrosine phosphorylation after cross-linking of the T15-Id sIgM was observed only in the wild-type sIgM transfectant. These results suggest that, while the NH₂-terminal third of the TM region is not involved in the process responsible for the ligand-induced reduction of surface expression of sIgM, it appears to be essential for subsequent transport of sIgM/ligand complexes to the lysosomal compartments, as well as efficient activation of tyrosine kinases. These results strongly suggest that sIg-mediated enhancement of specific antigen presentation reflects the ability of sIg to efficiently transport antigen to the lysosomal compartments, and possibly the activation of protein tyrosine kinases.