Prototype heel effect compensation filter for cone-beam CT

The prototype cone-beam CT (CBCT) has a larger beam width than the conventional multi-detector row CT (MDCT). This causes a non-uniform angular distribution of the x-ray beam intensity known as the heel effect. Scan conditions for CBCT tube current are adjusted on the anode side to obtain an acceptable clinical image quality. However, as the dose is greater on the cathode side than on the anode side, the signal-to-noise ratio on the cathode side is excessively high, resulting in an unnecessary dose amount. To compensate for the heel effect, we developed a heel effect compensation (HEC) filter. The HEC filter rendered the dose distribution uniform and reduced the dose by an average of 25% for free air and by 20% for CTDI phantoms compared to doses with the conventional filter. In addition, its effect in rendering the effective energy uniform resulted in an improvement in image quality. This new HEC filter may be useful in cone-beam CT studies.     

Diagnostic utility of galectin-3 and CD26/DPPIV as preoperative diagnostic markers for thyroid nodules

The aim of this study was to search for diagnostic markers that could correctly identify thyroid nodular lesions requiring urgent surgical treatment. We investigated whether galectin-3 and dipeptidyl peptidase IV (CD26/DPPIV) could be potential markers for improving the diagnostic accuracy of conventional cytology. Seventy-nine patients with histologically proven thyroid diseases were analyzed. The immunocytochemical staining results showed galectin-3 expression in neoplastic cells of all 37 papillary carcinomas, five of six follicular carcinomas, all three anaplastic carcinomas, one of three medullary carcinomas, and two of 14 follicular adenomas. All 16 adenomatous goiters were negative for galectin-3 immunostaining. On the other hand, all 37 papillary carcinomas, all six follicular carcinomas, and one of three anaplastic carcinomas revealed CD26/DPPIV expression, whereas all three medullary carcinomas were negative. Among benign thyroid lesions, four of 14 follicular adenomas and two of 16 adenomatous goiters exhibited varying degrees of immunoreactivity for CD26/DPPIV. RT-PCR analysis demonstrated overexpression of galectin-3 and CD26/DPPIV mRNAs in all six papillary and all three follicular carcinomas analyzed, whereas the mRNA expressions of these molecules were barely or not detectable in benign thyroid lesions and normal thyroid tissues, except for one case of follicular adenoma. In conclusion, we demonstrate that galectin-3 and CD26/DPPIV were consistently coexpressed at protein and mRNA levels in differentiated thyroid carcinomas. We propose that combined immunostaining for galectin-3 and CD26/DPPIV in the preoperative evaluation of thyroid nodules may play a role in accurate cytodiagnosis.     

Prevention of polyglutamine oligomerization and neurodegeneration by the peptide inhibitor QBP1 in Drosophila

Polyglutamine (polyQ) diseases are a growing class of inherited neurodegenerative diseases including Huntington's disease, which are caused by abnormal expansions of the polyQ stretch in each unrelated disease protein. The expanded polyQ stretch is thought to confer toxic properties on the disease proteins through alteration of their conformation leading to pathogenic protein-protein interactions including oligomerization and/or aggregation. Hypothesizing that molecules with selective binding affinity to the expanded polyQ stretch may interfere with the pathogenic properties, we previously identified Polyglutamine Binding Peptide 1 (QBP1) from combinatorial peptide phage display libraries. We show here that a tandem repeat of the inhibitor peptide QBP1, (QBP1)(2), significantly suppresses polyQ aggregation and polyQ-induced neurodegeneration in the compound eye of Drosophila polyQ disease models, which express the expanded polyQ protein under the eye specific promoter. Most importantly, (QBP1)(2) expression dramatically rescues premature death of flies expressing the expanded polyQ protein in the nervous system, resulting in the dramatic increase of the median life span from 5.5 to 52 days. These results suggest that QBP1 can prevent polyQ-induced neurodegeneration in vivo. We propose that QBP1 prevents polyQ oligomerization and/or aggregation either by altering the toxic conformation of the expanded polyQ stretch, or by simply competing with the expanded polyQ stretches for binding to other expanded polyQ proteins. The peptide inhibitor QBP1 is a promising candidate with great potential as a therapeutic molecule against the currently untreatable polyQ diseases.     

Effect of phospholipase A2 inhibitors on mouse T lymphocytes. I. Phospholipase A2 inhibitors exert similar immunological activities as glycosylation inhibiting factor

Since our previous experiments suggested that glycosylation-inhibiting factor (GIF) is a phosphorylated derivative of a phospholipase inhibitory protein, we determined whether other well-known phospholipase inhibitors may have similar biological activities. The results showed that phospholipase A2 (PLA2) inhibitors, such as recombinant human lipocortin I and ONO-RS-082, could switch T cell hybridoma 12H5 cells from the formation of glycosylated IgE-binding factors (IgE-BF) to the formation of unglycosylated IgE-BF, whereas neomycin, a phospholipase C inhibitor, failed to affect the nature of IgE-BF formed by the cells. The minimum concentrations of lipocortin I and ONO-RS-082 required for switching the 12H5 cells to the formation of unglycosylated IgE-BF were comparable to or less than IC50 of the inhibitors for PLA2. The ability of partially purified GIF to switch the 12H5 cells to the formation of unglycosylated IgE-BF was markedly enhanced by treatment of the preparation with alkaline phosphatase. It was also found that lipocortin I and ONO-RS-082, but not neomycin, facilitated the generation of GIF-producing T cells. When spleen cells of ovalbumin (OVA)-primed BDF1 mice were stimulated with homologous antigen and the activated T cells were propagated by recombinant IL-2 in the presence of GIF, lipocortin I, or ONO-RS-082, T cells obtained in the cultures constitutively produced their own GIF. Antigenic stimulation of the T cells induced the formation of unglycosylated IgE-BF and GIF with an affinity for OVA.(ABSTRACT TRUNCATED AT 250 WORDS)     

Virolysis and in vitro neutralization of HIV-1 by humanized monoclonal antibody hNM-01

Antibody humanization by transplanting the complimentarity determining region (CDR) to a human framework aims to reduce the response of the human immune system against a foreign molecule during passive immunization. We transferred the CDR from the murine monoclonal antibody (MAb) NM-01 to a human IgG frame. The humanized NM-01 (hNM-01) recognizes the same epitope on Human Immunodeficiency Virus type 1 (HIV-1) envelope as its murine progenitor, but with greater efficiency, and shows enhanced neutralization of HIV-1. We have shown that this increase in reactivity may be attributed to residue 4 of the humanized kappa chain, where the presence of a methionine residue rather than the murine leucine appears to promote a more advantageous conformation of the antigen-binding site, perhaps via packing interactions with the V(kappa) CDR1. The capacity of humanized NM-01 to neutralize direct clinical isolates was also examined with the expectation that hNM-01 will prove suitable for development as a therapeutic agent. This reshaped antibody reacted with several clinical isolates of HIV-1 tested. Moreover, we proved the ability of this antibody of its activation of complement by flow cytometry and electron microscopy analysis. Although hNM-01 alone was capable of neutralizing HIV-1, the presence of complement enhanced neutralization. The enhancement of complement activation was also observed in hNM-01 than murine progenitor. This finding supports a potential role for antibody-dependent complement-mediated virolysis and more effective neutralization in HIV-1 therapy.     

Laminin M is found in placental basement membranes, but not in basement membranes of neoplastic origin

Laminin is a high molecular weight glycoprotein found in all basement membranes studied to date. Two subunits of laminin, A and B, have been isolated and characterized from a variety of tumor matrices. Recently we have reported the finding, in human placenta, of a new laminin subunit which we termed M. In the present study we report on the presence of laminin M in placentae of other species such as bovine, rat and mouse. In addition, we have examined laminin extracted from mouse EHS-tumor, rat ED-PYS carcinoma and three human carcinoma cell lines. The laminin subunits were detected by the electroimmunoblot technique using antibodies against mouse, rat and human laminin. Laminin M could not be demonstrated either in the two murine tumors, or in the three different human neoplastic cell lines studied. If the absence of laminin M is the consequence of neoplastic transformation, then studies of the metabolism of this subunit may provide new information on neoplastic transformation and invasion, and a useful marker in tumor diagnosis.     

New hepatitis C virus (HCV) genotyping system that allows for identification of HCV genotypes 1a, 1b, 2a, 2b, 3a, 3b, 4, 5a, and 6a.

Recent studies have focused on whether different hepatitis C virus (HCV) genotypes are associated with different profiles of pathogenicity, infectivity, and response to antiviral therapy. The establishment of a simple and precise genotyping system for HCV is essential to address these issues. A new genotyping system based on PCR of the core region with genotype-specific PCR primers for the determination of HCV genotypes 1a, 1b, 2a, 2b, 3a, 3b, 4, 5a, and 6a was developed. A total of 607 samples (379 from Japan, 63 from the United States, 53 from Korea, 35 from Taiwan, 32 from China, 20 from Hong Kong, 15 from Australia, 6 from Egypt, 3 from Bangladesh, and 1 from South Africa) were tested by both the assay of Okamoto et al. (H. Okamoto, Y. Sugiyama, S. Okada, K. Kurai, Y. Akahane, Y. Sugai, T. Tanaka, K. Sato, F. Tsuda, Y. Miyamura, and M. Mayumi, J. Gen. Virol. 73:673-679, 1992) and this new genotyping system. Comparison of the results showed concordant results for 539 samples (88.8%). Of the 68 samples with discordant results, the nucleotide sequences of the HCV isolates were determined in 23, and their genotypes were determined by molecular evolutionary analysis. In all 23 samples, the assignment of genotype by our new genotyping system was correct. This genotyping system may be useful for large-scale determination of HCV genotypes in clinical studies.