Dual-energy CT for gastrointestinal bleeding.

Dual-energy computed tomography (DECT) can be used for various types of analyses, including iodine quantification, and its usefulness in diagnosing gastrointestinal diseases has been reported. This pictorial review describes the use of DECT in the diagnosis of gastrointestinal bleeding. Virtual non-contrast computed tomography (CT) is available in DECT and can be used as a substitute for pre-contrast CT in the case of gastrointestinal haemorrhage. The omission of pre-contrast CT can reduce radiation exposure by approximately 30%. A low-keV virtual monochromatic X-ray image (VMI) can increase the contrast of iodine, and iodine maps can provide better visibility of extravasation. These analytical images can provide a diagnosis with a high degree of confidence. In addition, the low-keV VMI clearly illustrates the vascular structure, which may be useful for improving the visibility of vascular lesions and for confirming the arterial anatomy before embolisation. Considering that these analytical images are created on the basis of contrast-enhanced CT, the positional information of organs is entirely identical, thus allowing the comparison of images regardless of intestinal peristalsis or body motion. In conclusion, the analytical images of DECT can solve the problems of conventional protocols, and DECT is considered useful in the imaging diagnosis of gastrointestinal bleeding.

Identification of patients with Graves' disease who benefit from high-dose radioactive iodine therapy.

OBJECTIVE: Radioactive iodine (RAI) therapy is a useful treatment for Graves' disease (GD). Most RAI sessions administer ≤ 500 MBq of iodine (I)-131. Sometimes patients require repeated RAI, often for longer periods of remission. We investigated the characteristics of patients for whom high dose (mostly 1110 MBq of I-131) RAI was effective as RAI therapy for GD. METHODS: We retrospectively analyzed the cases of 79 patients who underwent RAI for GD in a multicenter setting. We divided the patients into two groups based on the I-131 dose administered: the low dose (LD) group who received ≤ 500 MBq (n = 44) and the high dose (HD) group who received > 500 MBq (n = 35). The therapeutic effect was defined as achieving remission and reaching the point of participating in thyroid hormone replacement therapy within 1 year after RAI. We compared the LD and HD groups' remission rates and conducted a multivariate logistic regression analysis of predictive factors for remission. In a simulation, using the formula for predicting the probability of remission obtained from the analysis results, we estimated how much the remission rate would change if the I-131 dose is increased from 500 to 1110 MBq. RESULTS: The mean ± standard deviation I-131 dose administered in the LD group was 480 ± 6 MBq, and that of the HD group was 1054 ± 265 MBq. Thirty-five patients (80%) in the LD group and 26 patients (74%) in the HD group achieved remission; this difference in the remission rate was not significant. The multivariate analysis results demonstrated that the absorbed dose and thyroid-stimulating antibody (TSAb) were independent predictors of remission. Seven patients (8.9%) showed an increased probability of remission from < 50% to > 50% when the higher RAI dose was applied (1110 MBq instead of 500 MBq). The thyroid volume and TSAb values in these patients were relatively large at 54.7 ± 34.2 mL and 1378.4 ± 586.3%, respectively. CONCLUSION: Although the overall remission rate was not significantly different between the patients who received high- or low-dose I-131, treatment with high-dose RAI may improve the probability of remission in patients with a massive thyroid volume and/or high-TSAb Graves' disease.

Potential roles for ubiquitin and the proteasome during ribosome biogenesis.

We have investigated the possible involvement of the ubiquitin-proteasome system (UPS) in ribosome biogenesis. We find by immunofluorescence that ubiquitin is present within nucleoli and also demonstrate by immunoprecipitation that complexes associated with pre-rRNA processing factors are ubiquitinated. Using short proteasome inhibition treatments, we show by fluorescence microscopy that nucleolar morphology is disrupted for some but not all factors involved in ribosome biogenesis. Interference with proteasome degradation also induces the accumulation of 90S preribosomes, alters the dynamic properties of a number of processing factors, slows the release of mature rRNA from the nucleolus, and leads to the depletion of 18S and 28S rRNAs. Together, these results suggest that the UPS is probably involved at many steps during ribosome biogenesis, including the maturation of the 90S preribosome.

Phylogenetic and expression analysis of amphibian Xenopus Toll-like receptors.

An anuran amphibian, South African clawed frog (Xenopus laevis), is used to study the immune system, as it possesses a set of acquired immune system represented by T and B lymphocytes and the immunoglobulins. The acquired immune system is impaired throughout the larva and the metamorphosis stage in the amphibians. On the other hand, the role of innate immune system in the tadpole remains unclear. Recently, insect Toll protein homologues, namely, Toll-like receptors (TLRs), have been identified as sensors recognizing microbe-pattern molecules in vertebrates. Whole-genome analysis of Xenopus tropicalis supported the existence of the tlr genes in the frog. In this study, we annotated 20 frog tlr gene nucleotide sequences from the latest genome assembly version 4.1 on the basis of homology and identified cDNAs of the predicted frog TLR proteins. Phylogenetic analysis showed that the repertoire of the frog TLRs consisted of both fish- and mammalian-type TLRs. We showed that the frog TLRs are constitutively expressed in the tadpole as well as in the adult frog. Our results suggest that tadpoles are protected from microbes by the innate system that includes TLRs, despite impaired acquired immune system in tadpoles. This is the first report on the properties of TLRs in the most primitive terrestrial animals like amphibia.