Mycobacteria in the Intestine of Japanese Patients with Inflammatory Bowel Disease

Objectives : It is still controversial whether or not a mycobacterial infection may be a cause of Crohn's disease. Mycobaclerium paratuberculosis may be very difficult to detect using routine culture techniques. To clarify this, we delected mycobacterial DNA in patients with inflammatory bowel disease. Methods : IS900 sequences highly specific to M. paratuberculosis and groEL gene encoding a conserved mycobacterial antigen were studied in colonic mucosa using polymerase chain reaction (PCR). PCR products were analyzed by Southern blot hybridization. Results : IS900 sequences were detected in all (100%)of 10 patients with Crohan's disease, in 11 (61.1%) of 18 patients with ulcerative colitis, and in 14 (87.5%) of 16 control patients with noninflammatory bowel disease. All IS900 positive samples had groEL PCR products. Conclusions : Our results, on the basis of the prevalence, do not support the hypothesis that M. paratuberculosis is involved in the pathogenesis of Crohn's disease.     

Fully automated diagnostic system with artificial intelligence using endocytoscopy to identify the presence of histologic inflammation associated with ulcerative colitis (with video)

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Input–output analysis on the economic impact of medical care in Japan

Objectives

Since the Cabinet’s decision concerning the Basic Policies 2005, the Japanese government has implemented specific measures to suppress increases in national medical care expenditure. However, we believe that the economic significance of medical care should be quantified in terms of its economic impact on national medical care expenditure. No one has examined the economic impact of all medical institutions in Japan using data from a statement of profits and losses. We used an input–output analysis to quantitatively estimate economic impact of medical care and examined its estimation range with a probabilistic sensitivity analysis.

Methods

To estimate the economic impact and economic impact multipliers of all medical institutions in Japan, an input–output analysis model was developed using an input–output table, statement of profits and losses, margin rates, employee income rates, consumption propensity and an equilibrium output model. Probabilistic sensitivity analysis was conducted using a Monte Carlo simulation.

Results

Economic impact of medical care in all medical institutions was ¥72,107.4 billion ($661.5 billion). This impact yielded a 2.78-fold return of medical care expenditure with a 95 % confidence interval ranging from 2.74 to 2.90.

Conclusion

Economic impact of medical care in Japan was two to three times the medical care expenditure (per unit). Production inducement of medical care is comparable to other industrial sectors that are highly influential toward the economy. The contribution to medical care should be evaluated more explicitly in national medical care expenditure policies.     

A case of cryopyrin-associated periodic fever syndrome during canakinumab administration complicated by inflammatory bowel disease

Clinical Rheumatology - Cryopyrin-associated periodic fever syndrome (CAPS) is a highly debilitating disorder, which is characterized by unregulated interleukin-1β production driven by...     

Conductance of P2X4 purinergic receptor is determined by conformational equilibrium in the transmembrane region

Ligand-gated ion channels are partially activated by their ligands, resulting in currents lower than the currents evoked by the physiological full agonists. In the case of P2X purinergic receptors, a cation-selective pore in the transmembrane region expands upon ATP binding to the extracellular ATP-binding site, and the currents evoked by α,β-methylene ATP are lower than the currents evoked by ATP. However, the mechanism underlying the partial activation of the P2X receptors is unknown although the crystal structures of zebrafish P2X₄ receptor in the apo and ATP-bound states are available. Here, we observed the NMR signals from M339 and M351, which were introduced in the transmembrane region, and the endogenous alanine and methionine residues of the zebrafish P2X₄ purinergic receptor in the apo, ATP-bound, and α,β-methylene ATP-bound states. Our NMR analyses revealed that, in the α,β-methylene ATP-bound state, M339, M351, and the residues that connect the ATP-binding site and the transmembrane region, M325 and A330, exist in conformational equilibrium between closed and open conformations, with slower exchange rates than the chemical shift difference (<100 s⁻¹), suggesting that the small population of the open conformation causes the partial activation in this state. Our NMR analyses also revealed that the transmembrane region adopts the open conformation in the state bound to the inhibitor trinitrophenyl-ATP, and thus the antagonism is due to the closure of ion pathways, except for the pore in the transmembrane region: i.e., the lateral cation access in the extracellular region.In chemical neurotransmission, various neurotransmitters bind to ligand-gated ion channels expressed in the plasma membrane of postsynaptic cells, such as the NMDA, AMPA, and P2X receptors, leading to changes in membrane potential and the concentration of intracellular ions. Each ligand for a ligand-gated ion channel has a distinct ability to evoke currents (1), and the ligands are classified according to the evoked current level: such as, full agonists, partial agonists, and antagonists. Partial agonists of ligand-gated ion channels reportedly offer clinical advantages over antagonists and full agonists in antidepressant and smoking-cessation treatment (2, 3).Two mechanisms have been proposed for the partial activation of the ligand-gated ion channels: the equilibrium between the open and closed conformations and the distinct conformation of the partial agonist-bound states from the closed and open conformations (4, 5). In the crystal structures of the extracellular region of the AMPA receptor, in which the distances between the two extracellular domains are changed upon agonist binding, the interdomain distances in the partial agonist-bound states correlated with the conductance level, suggesting that the AMPA receptor adopts specific intermediately permeable conformations (4, 6).The P2X receptors are a family of cation channels gated by extracellular ATP (1, 7–9) and are involved in many physiological and pathophysiological processes (10–12). Seven subtypes of the P2X receptors have been identified in mammals (13), and they share ∼40% sequence identity. The P2X₄ receptor is involved in the pathogenesis of chronic neuropathic, inflammatory pain and the endothelial cell-mediated control of vascular tone (11, 14, 15). Compared with ATP, α,β-methylene ATP (α,β-meATP), in which the oxygen atom linking the α- and β-phosphorous atoms of ATP is replaced by a methylene group (Fig. S1A), reportedly induces a lower maximum current in cells expressing the mouse, rat, and human P2X₄ receptors and other P2X receptors (16, 17).Open in a separate windowFig. S1.Characterization of the P2X₄ receptor. (A) Chemical structures of ATP and α,β-meATP. (B and C) TEVC recordings of ATP- and α,β-meATP-evoked currents from rat P2X₄ receptor expressed in Xenopus oocytes, respectively. In B, the currents were evoked twice by ATP (30 μM, 1 min, black bar). In C, the currents were firstly evoked by ATP (30 μM, 1 min, black bar) and subsequently by α,β-meATP (300 μM, 1 min, black bar). (D) TEVC recording of the ATP-evoked current (30 μM, 30 s, black bar) from the N-terminally EGFP-tagged ΔzfP2X₄–A′ construct expressed in Xenopus oocytes. (E) Size exclusion chromatogram of purified EGFP-tagged ΔzfP2X₄–A′ in rHDLs. Elution volumes corresponding to 17.0, 12.2, 10.4, and 7.1 nm Stokes diameters were determined by thyroglobulin, ferritin, catalase, and BSA, respectively. V₀ and 1CV are void volume and single column volume, respectively. (F) SDS/PAGE analyses of purified ΔzfP2X₄–A′ embedded in rHDLs. The samples were analyzed by 12% SDS/PAGE with Coomassie Brilliant Blue staining. (G) Measurement of [³H]ATP saturation binding to the purified ΔzfP2X₄–A′ in rHDLs. (H and I) Estimation of the effects of deuteration based on the crystal structures of zfP2X₄ (PDB ID code 4DW1) and the deuteration incorporation rates. The plots on the Left (without deuteration) and the Right (with deuteration) are the sums of the inverse sixth power of the distances between pseudoatoms centered on the methyl hydrogens of M108, M249, M268, or M325 and each hydrogen atom in the crystal structure of zfP2X₄ (sums of the r⁻⁶) and the sums of the r⁻⁶ multiplied by [1 − (deuterium incorporation rates)] of each hydrogen atom, respectively. The graphs in H and I were calculated from the crystal structure in the apo state (PDB ID code 4DW0) and that in the ATP-bound state (PDB ID code 4DW1), respectively. Sums of the r⁻⁶ of each methionine methyl group and Hαβγ of the intraresidue methionine (green), Hαβγ of the interresidue methionine (light green), Hαβ of tyrosine (light violet), Hδεζη of tryptophan (orange), Hαβδεζ of phenylalanine (pink), Hαβγ of valine (blue), Hαβγδ of leucine (light blue), Hαβγδ of isoleucine (cyan), Hαβγ of threonine (light cyan), Hαβ of alanine (red), Hαβγδ of arginine (dark blue), Hα of glycine (dark green), and Hαβ of serine (magenta) residues, and the other hydrogens connected to carbon atoms (other unexchangeable hydrogens, light gray) are shown with colors. Hydrogen atoms connected to nitrogen, oxygen, or sulfur atoms were not considered in these calculations because these hydrogens should be exchanged with deuterium in D₂O. The deuterium incorporation rates of the hydrogen atoms within each methionine residue (intraresidue) and the deuterium incorporation rates of other methionine residues (interresidue) were set to 98% and 85%, respectively, because the methionine residues would be derived from 85% of [α-, β-, γ-98% ²H-, methyl-¹³C]-methionine and 15% of nonlabeled methionine in the medium.The crystal structures of zebrafish P2X₄ receptor (zfP2X₄) (18, 19), together with mutational analyses (20–26), provided the structural basis for the channel opening of P2X receptors upon ATP binding. In the crystal structures, zfP2X₄ forms a homotrimer (27, 28), in which the transmembrane region of each subunit is composed of two helices (19). In the crystal structure of zfP2X₄ in the ATP-bound state, three ATP molecules are bound to the intersubunit nucleotide binding pockets. In addition, the region that connects the ATP-binding site and the transmembrane region, which is referred to as the “lower body” (Fig. 1 A and B), is expanded by ∼10 Å in the ATP-bound state, and a pore is formed in the transmembrane region, which is proposed to expand by the iris-like movement of the transmembrane helices (18). However, the mechanism underlying the partial activation of P2X receptors is unknown because the structures of the P2X receptors have not been examined in the partial agonist-bound states.Open in a separate windowFig. 1.NMR resonances from the endogenous methionine residues of zfP2X₄ in rHDL. (A and B) Distribution of the methionine residues in the ΔzfP2X₄–A′. One subunit from the crystal structure of zfP2X₄ in the apo form (A) (PDB ID code 4DW0) and one from the ATP-bound form (B) (PDB ID code 4DW1) are shown in ribbons. The lower body and the right flipper are yellow. The A330 residues, the methionine residues, and the residues in which methionine mutations were introduced, L339 and L351, are depicted by green sticks. ATP is depicted by red sticks. Dummy atoms generated by Orientations of Proteins in Membranes (OPM), which represent membrane boundary planes, are gray. (C) Overlaid ¹H-¹³C HMQC spectra of [²H-11AA, α, β-²H, methyl-¹³C-Met]ΔzfP2X₄-A′, embedded in rHDLs, in the apo state (black) and the ATP-bound state (red). The regions with resonances from methionine residues are shown, and the assigned resonances are indicated. The centers of the resonances are indicated with dots. Cross-sections at lines through the centers of each resonance in the ATP-bound state and the cross-sections of the spectra using [α, β-²H, methyl-¹³C-Met]ΔzfP2X₄-A′ are shown on the top of the overlaid spectra. The intensities of the cross-sections were normalized by the concentration of ΔzfP2X₄-A′ and the conditions of the NMR measurements.The P2X₄ receptor used in the previous crystallographic studies was solubilized by detergents, which are widely used for structural investigations of membrane proteins, but the P2X₄ receptor is embedded in lipid bilayers under physiological conditions. It was recently reported that reconstituted high-density lipoproteins (rHDLs), which are also known as nanodiscs (29), can accommodate membrane proteins within a 10-nm-diameter disk-shaped lipid bilayer (30). The rHDLs reportedly provide a lipid environment with more native-like properties, compared with liposomes, in terms of the lateral pressure and curvature profiles because detergent micelles have strong curvature and different lateral pressure profiles from lipid membranes (31). Our NMR analyses of a G protein-coupled receptor (GPCR) and an ion channel in rHDL lipid bilayers revealed that the population and the exchange rates of the conformational equilibrium determine their signal transduction and ion transport activities (32–34) and that the population of the active conformation of the GPCR in rHDLs correlated better with the signaling levels than that in detergent micelles (32). Therefore, NMR investigations of membrane proteins in the lipid bilayer environments of rHDLs are necessary for accurate measurements of the exchange rates and the populations in conformational equilibrium.Here, we used NMR to observe the conformational equilibrium of the alanine and methionine residues of zfP2X₄ bound to α,β-meATP in rHDLs. Based on the conformational equilibrium, we discuss the mechanism underlying the partial activation of P2X receptors.     

Prognostic significance of the MDM2/HMGA2 ratio and histological tumor grade in dedifferentiated liposarcoma

Dedifferentiated liposarcoma (DDLPS) is a relatively common soft tissue sarcoma that results from the progression of well‐differentiated liposarcoma (WDLPS). This study aimed to investigate the progression process and to clarify the pathological and genetic factors related to poor prognosis in DDLPS. In 32 DDLPS cases and five WDLPS cases, genetic factors were analyzed by custom comparative genomic hybridization (CGH) array, which was designed to densely cover gene regions known to be frequently amplified in WD/DDLPS. The analyses comparing primary and metastatic lesions and those comparing histologically different areas in the same tumor revealed intra‐tumoral genetic heterogeneity and progression. According to a prognostic analysis comparing the good‐prognosis and the poor‐prognosis groups, we selected MDM2 and HMGA2 as candidate genes associated with poor and good prognosis, respectively. The ratios of the amplification or gain levels of MDM2 and HMGA2 expressed in log ratios (log[MDM2/HMGA2] = log[MDM2]‐log[HMGA2]) were significantly associated with prognosis. An amplification or gain level of MDM2 that was more than twice that of HMGA2 (MDM2/HMGA2 > 2, log[MDM2/HMGA2] > 1) was strongly related to poor OS (P < .001) and poor distant metastasis‐free survival (DMFS) (P < .001). In the pathological analysis of 44 cases of DDLPS, histological tumor grade, cellular atypia, and MDM2 immunoreactivity were related to overall survival (OS), while HMGA2 immunoreactivity tended to be associated with OS. Cellular atypia was also associated with DMFS. In conclusion, histological grade and MDM2 expression were determined to be prognostically important, and the MDM2/HMGA2 amplification or gain ratio was found to have significant prognostic value by the custom CGH array analysis.