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Tomoaki Ando

Publications and source records attributed to Tomoaki Ando.

At least 19 recordsLinked to original sources
PubMed2007

Difficulty in diagnosing autoimmune pancreatitis by imaging findings.

BACKGROUND: Autoimmune pancreatitis (AIP) presents as diffuse enlargement of the pancreas and as diffuse irregular narrowing of the main pancreatic duct. However, some AIP cases are difficult to diagnose because of atypical imaging findings. OBJECTIVE: To clarify a variety of imaging findings of AIP and the reason for its misdiagnosis. DESIGN: We examined the imaging findings of 37 AIP cases and also examined misdiagnosed cases of AIP to determine their reasons for misdiagnosis. PATIENTS: A total of 37 patients with AIP who reported to our hospital or its affiliate over a 17-year period (1989 to May 2005). RESULTS: Patients in 15 AIP cases showed segmental narrowing of the main pancreatic duct. There were 6 patients with focal enlargement of the pancreas, whereas 3 patients showed no enlargement. There were 3 cases of calcification of the pancreas. Pancreatic cysts were detected in 2 patients. Abdominal US showed multiple low-echoic masses in 1 case and a single mass in 3 cases. Sixteen patients had stenosis of the bile duct at the hilar hepatic lesion and/or the intrahepatic duct. Only 7 patients had typical AIP findings. Six patients were misdiagnosed with pancreatic cancer and 2 with bile-duct cancer. Seven cases were surgically treated. Five cases were misdiagnosed because of the nonexistence of, or the unfamiliarity with, the concept of AIP and sclerosing cholangitis with AIP. Another 3 cases were diagnosed with pancreatic cancer because of segmental stenosis of the main pancreatic duct and no or focal enlargement of the pancreas. CONCLUSIONS: The results of this study suggest that AIP presents a variety of imaging findings. The most important diagnostic factor is clinician awareness of the concept of AIP and the diverse nature of imaging findings.

Autoimmune Diseases↗
PubMed2006

Characterization of extracellular RNAs produced by the marine photosynthetic bacterium Rhodovulum sulfidophilum.

The marine photosynthetic bacterium Rhodovulum sulfidophilum produces extracellular nucleic acids that are involved in its flocculation. These were found to be produced concomitantly with cell growth. The RNA fraction of these extracellular nucleic acids was subjected to cDNA analysis by applying a micro RNA cloning method and found to contain mainly fully mature-sized tRNAs and fragments of 16S and 23S rRNAs. Analyses of modified bases and genes of the RNAs revealed no structural difference between the intracellular and extracellular RNAs. This is the first report of structural analyses of bacterial extracellular RNAs.

Base Sequence↗
PubMed2005

Reversal of experimental colitis disease activity in mice following administration of an adenoviral IL-10 vector.

Genetic deficiency in the expression of interleukin-10 (IL-10) is associated with the onset and progression of experimental inflammatory bowel disease (IBD). The clinical significance of IL-10 expression is supported by studies showing that immune-augmentation of IL-10 prevents inflammation and mucosal damage in animal models of colitis and in human colitis. Interleukin-10 (IL-10), an endogenous anti-inflammatory and immunomodulating cytokine, has been shown to prevent some inflammation and injury in animal and clinical studies, but the efficacy of IL-10 treatment remains unsatisfactory. We found that intra-peritoneal administration of adenoviral IL-10 to mice significantly reversed colitis induced by administration of 3% DSS (dextran sulfate), a common model of colitis. Adenoviral IL-10 (Ad-IL10) transfected mice developed high levels of IL-10 (394 +/- 136 pg/ml) within the peritoneal cavity where the adenovirus was expressed. Importantly, when given on day 4 (after the induction of colitis w/DSS), Ad-IL10 significantly reduced disease activity and weight loss and completely prevented histopathologic injury to the colon at day 10. Mechanistically, compared to Ad-null and DSS treated mice, Ad-IL10 and DSS-treated mice were able to suppress the expression of MAdCAM-1, an endothelial adhesion molecule associated with IBD. Our results suggest that Ad-IL10 (adenoviral IL-10) gene therapy of the intestine or peritoneum may be useful in the clinical treatment of IBD, since we demonstrated that this vector can reverse the course of an existing gut inflammation and markers of inflammation.

Journal Article↗
PubMed2005

DSS-induced colitis is exacerbated in STAT-6 knockout mice.

BACKGROUND: Several transcription factors have been proposed to regulate IBD including the signal transducer and activator of transcription-6 (STAT-6). METHODS: The role of STAT-6 was examined in the 5% dextran sulfate sodium (DSS)-induced murine model of colitis using STAT-6 and wildtype mice. RESULTS: The disease activity index (DAI) revealed a significant increase in DAI in STAT-6 mice over STAT-6 mice given DSS. Both STAT-6 and wildtype mice displayed severe inflammation and crypt damage. Additionally, STAT-6 mice showed significant injury to the proximal colon compared with their littermate controls. Furthermore, STAT-6 mice receiving DSS had dramatically higher levels of serum nitrite/nitrate than all other groups. STAT-6 animals also displayed higher levels of inteferon-gamma than wildtype mice. CONCLUSIONS: Because STAT-6 has been reported to regulate the expression and activity of inducible NO synthase (iNOS), our data suggest that, in DSS colitis, STAT-6 may modulate iNOS, to limit NO formation and control the extent of inflammation in the colon. We conclude that STAT-6 may normally play an important regulatory role in the pathogenesis of inflammatory bowel disease, possibly through modulation of iNOS and interferon-gamma.

Animals↗
PubMed2005

Systemic extrapancreatic lesions associated with autoimmune pancreatitis.

OBJECTIVES: Autoimmune pancreatitis (AIP) is often associated with systemic extrapancreatic lesions. We studied 31 cases of AIP to clarify the diversity of associated systemic extrapancreatic lesions and the differences between AIP with and without systemic extrapancreatic lesions. METHODS: The clinical features and courses were compared by age, sex, and blood chemistry between those with and without systemic extrapancreatic lesions. In addition, we reviewed the available literature on systemic extrapancreatic lesions with AIP. RESULTS: Seven of the 31 cases of AIP had associated systemic extrapancreatic lesions, which were diagnosed simultaneously with AIP; however, 1 case presenting with various extrapancreatic lesions was diagnosed independently of the AIP lesion. Patients with systemic extrapancreatic lesions needed maintenance steroid therapy for AIP in 4 cases and systemic extrapancreatic lesions in 2 cases; the ratio of cases requiring maintenance steroid therapy was significantly higher among those with systemic extrapancreatic lesions (6/8) than those without (7/23). There were no significant differences between groups with regard to age, sex, extent of narrowing of the main pancreatic duct, and enlargement of the pancreas. gamma-globulin, IgG, and IgG4 levels were significantly higher in patients with AIP with systemic extrapancreatic lesions than those without. The systemic extrapancreatic lesions associated with AIP found in the literature were Sjögren syndrome, ulcerative colitis, retroperitoneal fibrosis, sialadenitis, thyroiditis, and idiopathic thrombocytopenic purpura. CONCLUSIONS: The results of this study suggest that, when encountering a case of AIP with elevated levels of gamma-globulins, IgG, and IgG4, an effort should be made to detect other systemic extrapancreatic abnormalities and initiate steroid administration.

Aged↗
PubMed2005

Clinical differences between primary sclerosing cholangitis and sclerosing cholangitis with autoimmune pancreatitis.

OBJECTIVES: Sclerosing cholangitis (SC) with autoimmune pancreatitis (AIP) is similar to primary sclerosing cholangitis (PSC) with regard to cholangiographic findings, but only the former responds well to steroid therapy. This report concentrates on the clinical differences between these diseases. METHODS: The presenting complaint or abnormality, associated disease, cholangiographic findings, pancreatic changes, treatment, and clinical course were studied for several cases of PSC (n = 27) and SC with AIP (n = 20). RESULTS: SC with AIP as a diagnosis occurs abruptly with obstructive jaundice compared with PSC where diagnosis is often based on findings of asymptomatic liver test abnormalities. In addition, inflammatory bowel disease is only associated with PSC. The most prominent features of cholangiograms for the SC with AIP cases were stenosis of the lower common bile duct. However, sclerosing changes in the intra- and extrahepatic bile ducts or hilar hepatic region were observed for half of the cases. Only PSC showed stage III or IV liver biopsy findings. IgG4 was significantly higher in SC with AIP. CONCLUSIONS: SC with AIP and PSC are different clinical entities.

Adult↗
PubMed2004

Combination therapy with an angiotensin-converting enzyme inhibitor and an angiotensin II receptor blocker synergistically suppresses chronic pancreatitis in rats.

We recently demonstrated that both lisinopril and candesartan, an angiotensin-converting enzyme inhibitor and angiotensin II type 1 receptor blocker, respectively, attenuate pancreatic inflammation and fibrosis in male Wistar Bonn/Kobori (WBN/Kob) rats. The purpose of the present study was to assess whether combination therapy with low doses of both, ineffective when given alone, might synergistically exert protective effects. Lisinopril, candesartan, or a combination of both in drinking water was administered to 10-week-old male WBN/Kob rats for 10 weeks. Parameters of inflammation and fibrosis, positive immunostaining for alpha-smooth muscle actin, and gene expression of cytokine and growth factors were assessed, as well as circulating renin-angiotensin system components. Dose-dependent effects of combination therapy were also investigated. Only combination therapy attenuated gross alterations in the pancreas, as quantitatively confirmed by increases in pancreatic weights and decreases in myeloperoxidase activity, hydroxyproline content, histologic scores, relative fibrosis area, and relative area of alpha-smooth muscle actin-positive cells. Combination therapy suppressed up-regulation of tumor necrosis factor-alpha, platelet-derived growth factor-receptor beta, and transforming growth factor-beta1 mRNA in the pancreas. Dose dependence of combination therapy was recognized with reference to improvement in these parameters. The conclusions are that combination therapy synergistically alleviated pancreatic inflammation and fibrosis in male WBN/Kob rats. This effect may be related to suppression of tumor necrosis factor-alpha, platelet-derived growth factor-receptor beta, and transforming growth factor-beta1 mRNA. Compared with the either therapy alone, combination therapy with an angiotensin-converting enzyme inhibitor and an angiotensin II type 1 receptor blocker may be more beneficial for treating chronic pancreatitis.

Actins↗
PubMed2004

Extracellular RNAs produced by a marine photosynthetic bacterium Rhodovulum sulfidophilum.

A marine photosynthetic bacterium Rhodovulum sulfidophilum secretes nucleic acids. Previously we have shown that these extracellular nucleic acids are a mixture of double-strand DNAs and single-strand RNAs. Here, we have more closely analyzed the RNA fraction of these extracellular nucleic acids. We determined the sequences of secreted RNAs. They have same sequences with parts of Rhodovulum sulfidophilum DSM 2351 16SrRNA or parts of ribosomal RNA operon of related species. Some of them were tRNAs. Interestingly, these tRNAs were mature tRNAs that had mature sizes, mature 5'-ends as well as 3'-CCA sequences. Additionally, we have found that these sequences were coded on genome, as expected. All of the secreted RNAs we detected may be parts of intracellular RNAs.

Electrophoresis, Polyacrylamide Gel↗
PubMed2004

Mutational analyses of neighboring domains of active center of RNase P ribozyme.

We prepared series of P2-P4 domain variants of Escherichia coli ribonuclease P (RNase P) ribozyme, and examined enzymatic activities of them. The results indicated that mutations in these domains did not affect the cleavage site selection of the enzyme, but affected cleavage efficiencies and dependence on magnesium ion concentrations.

Base Sequence↗
PubMed2004

Examining the bases of the J3/4 domain of Escherichia coli ribonuclease P.

We prepared several mutants of the J3/4 and P4 domains of Escherichia coli ribonuclease P (RNase P): A62G, A62U, G63C/G64C, A65G, A67G, U69A, U69G, U69C, U69Delta, and U69UU. Comparison of the ribozyme and holo enzyme reactions at various concentrations of magnesium ions showed that the presence of a bulge at U69 in the P4 domain was important in the holo enzyme. The results also showed that the conserved bases G63 and G64 in the J3/4 domain were important for efficient ribozyme reactions but were replaceable in the presence of the protein component. Our data showed that the bases in the J3/4 and P4 domains displayed different responses to the metal ions that were affected by the presence of the protein component.

Base Sequence↗
PubMed2004

The natural intron sequence of human tyrosine pre-transfer RNA is not a temporal stabilizer for cloverleaf structure.

We have developed the hyperprocessing technique to evaluate the stability of the cloverleaf shape of pre-transfer RNA (pre-tRNA). Application of this strategy to hyperprocessible human tyrosine pre-tRNA indicated that the natural intron sequence did not contribute to stabilization of the cloverleaf shape of this pre-tRNA, while the artificial intron with elongated anticodon-stem completely inhibited hyperprocessing of it. Our data suggested that the contemporary intron sequence may be a vestige of the ancient pre-biotic world, but not has been retained as a temporal stabilizer of the pre-tRNA before the base modifications.

Base Sequence↗
PubMed2003

Candesartan, an angiotensin II receptor antagonist, suppresses pancreatic inflammation and fibrosis in rats.

Angiotensin-converting enzyme inhibitors and angiotensin receptor antagonists attenuate fibrosis in the kidney, heart, and liver by suppressing transforming growth factor-beta1 mRNA and decreasing production of extracellular matrix proteins. We recently demonstrated that lisinopril, an angiotensin-converting enzyme inhibitor, alleviates pancreatic inflammation and fibrosis in male Wistar Bonn/Kobori rats. The involvement of angiotensin II receptor and its receptor interaction in the pathogenesis of spontaneous chronic pancreatitis was assessed in this model. Candesartan, an angiotensin II receptor antagonist, was administered in drinking water (10.5, 42, or 125 mg/l) to 10-week-old male WBN/Kob rats for 10 weeks and inflammatory parameters, fibrosis, and gene expression of renin-angiotensin system components and transforming growth factor-beta1 were assessed in the pancreas. Immunostaining for alpha-smooth muscle actin was also performed. Candesartan significantly suppressed decrease in pancreatic weight and increases in pancreatic myeloperoxidase activity, hydroxyproline content, ratio of fibrous tissue, histologic scores, and ratio of alpha-smooth muscle actin-positive cells (activated pancreatic stellate cells) at 20 weeks. The high dose enhanced the expression of angiotensinogen and angiotensin II receptor type 2 mRNA and suppressed the overexpression of transforming growth factor-beta1 mRNA. The conclusion is that candesartan alleviates chronic pancreatitis and fibrosis by suppressing the overexpression of transforming growth factor-beta1, resulting in prevention of activation of pancreatic stellate cells in male WBN/Kob rats. We propose that angiotensin II receptor type 1 antagonists may be useful for the treatment of chronic pancreatitis involving angiotensin II interaction with its receptor.

Actins↗
PubMed2003

Kupffer-cell depletion attenuates colonic and extracolonic granulomatous inflammation in chronic colitis.

Intramural injection of peptidoglycan-polysaccharide polymers into the distal colon in rats induces granulomatous colitis associated with extracolonic manifestations. We sought to clarify the effects of Kupffer-cell depletion induced by the intravenous administration of gadolinium on colonic and extracolonic inflammation in this model. The effects of Kupffer-cell depletion on acute and chronic inflammation were evaluated 3 days and 3 weeks after injection of peptidoglycan-polysaccharide, respectively. We assessed the effects of gadolinium on colonic cytokine levels in vivo and the viability of elicited peritoneal macrophages and peptidoglycan-polysaccharide-induced production of nitrite, an indirect index of nitric oxide production, by these cells in vitro. A single injection of gadolinium caused a marked decrease in the number of Kupffer cells stained with antibodies within 3 days. Gadolinium treatment did not alter acute inflammation at 3 days. Repeated treatment with gadolinium dramatically attenuated grossly observed chronic inflammation, including thickening of colon wall, hepatic and splenic nodules, and swelling of foot joints; and significantly reduced the proportional areas occupied by granulomas in the colon, liver, and spleen at 3 weeks. These protective effects were reflected in significant reduction in colon and liver weights; gross scores; colonic myeloperoxidase activity, an indirect quantitative index of granulocyte infiltration; colonic interleukin-1beta levels; plasma nitrite and nitrate levels; and decreased tendency toward arthritis. Although gadolinium did not cause injury in elicited peritoneal macrophages in vitro, the compound dose-dependently attenuated peptidoglycan-polysaccharide-induced production of nitrite by these cells. Chronic Kupffer-cell depletion attenuates peptidoglycan-polysaccharide-induced granulomatous inflammation in the colon, liver, and spleen and reduces the incidence of arthritis, possibly by suppressing the production of interleukin-1beta and nitric oxide.

Animals↗
PubMed2003

Substrate shape specificity of E coli RNase P ribozyme is dependent on the concentration of magnesium ion.

The bacterial RNase P ribozyme can accept a hairpin RNA with CCA-3' tag sequence as well as a cloverleaf pre-tRNA as substrate in vitro, but the details are not known. By switching tRNA structure using an antisense guide DNA technique, we examined the Escherichia coli RNase P ribozyme specificity for substrate RNA of a given shape. Analysis of the RNase P reaction with various concentrations of magnesium ion revealed that the ribozyme cleaved only the cloverleaf RNA at below 10 mM magnesium ion. At 10 mM magnesium ion or more, the ribozyme also cleaved a hairpin RNA with a CCA-3' tag sequence. At above 20 mM magnesium ion, cleavage site wobbling by the enzyme in tRNA-derived hairpin occurred, and the substrate specificity of the enzyme became broader. Additional studies using another hairpin substrate demonstrated the same tendency. Our data strongly suggest that raising the concentration of metal ion induces a conformational change in the RNA enzyme.

Base Sequence↗
PubMed2003

Revisiting the substrate recognition of bacterial ribonuclease P: in the view of the recognition of the base N73 in the substrate.

The RNA subunit of bacterial ribonuclease P (RNase P) is a ribozyme which can cleave a canonical cloverleaf tRNA precursor and a hairpin RNA with a CCA-3' tag sequence as its substrate. At high concentration of Mg ion, the substrate shape preference of the ribozyme becomes broader to accept a hairpin shape RNA. In hairpin RNA cleavage reactions, we found that the base interaction between the base U294 of E. coli ribozyme and the base N73 of the substrate RNA did not obey the response according to the Watson-Crick type interaction which is usually observed in the interaction between the base U294 of ribozyme and the base N73 of tRNA precursor.

Base Pairing↗
PubMed2003

Recognition of tRNA bottom half by bacterial ribonuclease P.

Bacterial ribonuclease P (RNase P) contains a catalytic RNA that cleaves precursor tRNA to form the 5'-end of mature tRNA. Bacterial RNase P mainly recognizes the acceptor stem and T arm modules of tRNA molecules. The region consisting of T arm, acceptor stem and 3' CCA motif in the tRNA is generally termed "top half", and the region consisting of the others, anticodon arm, extra loop and D arm, is called "bottom half". The stems in the top half contribute to recognition, but effects of the bottom half have not been elucidated. To study the effects of the bottom half on the RNase P recognition, we have synthesized several mutant substrates that have the bottom half on different positions along the top half stem. Most of these mutants were cleaved by Escherichia coli RNase P precisely at the expected position, but the cleavage efficiencies were very different especially at low Mg2+ concentration. We also found that RNase P holoenzyme prefered somewhat mutated tRNA precursor to the wild-type tRNA precursor.

Animals↗
PubMed2003

Bacterial ribonuclease P reaction is affected by substrate shape and magnesium ion concentration.

Bacterial RNase P is a ribonucleoprotein enzyme which cleaves 5'-precursor sequence of pre-tRNA for pre-tRNA maturation. The RNA component of bacterial RNase P is ribozyme. It recognizes cloverleaf shaped pre-tRNA and hairpin RNA with a CCA-3' tag sequence as its substrates. Previously, we reported that the substrate recognition of the E. coli RNase P ribozyme depends on the concentration of magnesium ion in vitro. In this report, we examined the substrate shape preference of the Bacillus subtilis RNase P ribozyme and compared it with that of the E. coli ribozyme. The results of the B. subtilis ribozyme displayed same tendency as the E. coli ribozyme. We also examined the effect of the protein component of the E. coli RNase P. Under the conditions tested, magnesium ion concentration dependency to substrate shape recognition was not observed when the holo enzyme was used.

Bacillus subtilis↗