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Biomedical subjects

Naoki Takahashi

Publications and source records attributed to Naoki Takahashi.

At least 19 recordsLinked to original sources
PubMed2007

Renal involvement in patients with autoimmune pancreatitis: CT and MR imaging findings.

PURPOSE: To retrospectively evaluate computed tomographic (CT) and magnetic resonance (MR) imaging renal findings at clinical presentation, during treatment, and at follow-up in patients with autoimmune pancreatitis (AIP). MATERIALS AND METHODS: This HIPAA-compliant study received institutional review board approval. All patients included had previously consented to the use of their medical records for the purpose of research. Forty-five patients (38 male and seven female patients; mean age, 64 years) with diagnosis of AIP were included. Forty patients underwent CT or MR imaging at clinical presentation; 33 patients (including five without imaging at presentation) underwent follow-up. CT and MR images were reviewed in consensus by two radiologists for the presence of renal involvement. Various features were evaluated. Clinical characteristics at presentation were compared between patients with and patients without renal involvement. RESULTS: Of the 40 patients who underwent imaging at presentation, 14 (35%) had renal involvement (12 with parenchymal involvement and five with extraparenchymal involvement). Renal parenchymal lesions showed decreased enhancement and appeared as small peripheral cortical nodules, round or wedge-shaped lesions, or diffuse patchy involvement. Thirteen patients with renal involvement at presentation underwent a follow-up study. Renal lesions in 10 patients regressed (in nine, after steroid treatment) but progressed in three patients without steroid treatment. Renal lesions were found in two other patients during follow-up. No significant difference in the clinical characteristics was found between patients with and patients without renal involvement. CONCLUSION: Renal involvement in patients with AIP is relatively common and predominantly involves the cortex of the kidney. The lesions improve after steroid treatment but can progress without steroid treatment.

Adolescent↗
PubMed2006

Negative correlation of G+C content at silent substitution sites between orthologous human and mouse protein-coding sequences.

We conducted a genome-wide analysis of variations in guanine plus cytosine (G+C) content at the third codon position at silent substitution sites of orthologous human and mouse protein-coding nucleotide sequences. Alignments of 3776 human protein-coding DNA sequences with mouse orthologs having >50 synonymous codons were analyzed, and nucleotide substitutions were counted by comparing sequences in the alignments extracted from gap-free regions. The G+C content at silent sites in these pairs of genes showed a strong negative correlation (r = -0.93). Some gene pairs showed significant differences in G+C content at the third codon position at silent substitution sites. For example, human thymine-DNA glycosylase was A+T-rich at the silent substitution sites, while the orthologous mouse sequence was G+C-rich at the corresponding sites. In contrast, human matrix metalloproteinase 23B was G+C-rich at silent substitution sites, while the mouse ortholog was A+T-rich. We discuss possible implications of this significant negative correlation of G+C content at silent sites.

Amino Acid Sequence↗
PubMed2006

MR imaging features of pure mucinous carcinoma of the breast.

OBJECTIVE: To characterize MR imaging features of pure mucinous carcinoma of the breast. MATERIALS AND METHODS: MR images obtained from 16 women (age range, 29-81; mean age, 57 years) with pure mucinous carcinoma of the breast determined at surgery were reviewed. The MR findings used were shape, margin, internal mass enhancement, kinetic curve pattern on dynamic study, signal intensity on short time inversion recovery (STIR) T2-weighted images, and non-mass-like enhancement around the main tumor. Non-mass-like enhancement was compared with the presence of extensive intraductal component (EIC) on histopathological findings. RESULTS: Eleven tumors (69%) had lobular contour, and nine tumors (56%) had smooth margin. Eight tumors (50%) showed rim enhancement and six tumors (38%) showed heterogeneous enhancement. Fourteen tumors (88%) showed a persistent enhancing pattern on kinetic curve. Fifteen tumors exhibited homogenous strongly high signal intensity on STIR T2-weighted images. In six cases with EIC, five cases had non-mass-like enhancement around the main mass. CONCLUSIONS: MR findings such as lobular shape, rim or heterogeneous enhancement, persistent pattern on kinetic curve, and homogeneous strongly high signal intensity on STIR T2-weighted images may be useful in diagnosing pure mucinous carcinoma. Moreover, linear-ductal enhancement around main mass may indicate presence of EIC.

Adenocarcinoma, Mucinous↗
PubMed2006

A series of luminescent Cu(I) mixed-ligand complexes containing 2,9-dimethyl-1,10-phenanthroline and simple diphosphine ligands.

A series of Cu(I) mixed-ligand complexes containing dmp (2,9-dimethyl-1,10-phenanthroline) and one of simple diphosphine ligands (Ph2P(CH2)nPPh2) were prepared. Among the complexes, [Cu(dppp)(dmp)]PF6 (n=3) and [Cu2(dppb)2(dmp)2](PF6)2 (n=4) were characterized by X-ray structure analyses. The dppp complex has been characterized as a mononuclear complex, while [Cu2(dppb)2(dmp)2]2+ exists as a dinuclear complex in which two dppb ligands bridge between the two Cu(I) atoms. Although the distorted tetrahedral structures around the central metals of the two complexes are similar, the P-Cu-P angles are different between the two complexes. All of the series of complexes show photoluminescence in solution, and the intensity of the luminescence increases with n (n=2-4). The non-radiative rate constants of the complexes decrease markedly with n although radiative rate constants of the complexes are similar.

Journal Article↗
PubMed2006

Diagnosis of autoimmune pancreatitis: the Mayo Clinic experience.

BACKGROUND & AIMS: The Japan Pancreas Society criteria for diagnosis of autoimmune pancreatitis (AIP) mandate presence of characteristic imaging (diffuse pancreatic enlargement with diffusely irregular, narrow pancreatic duct). AIP has unique histologic features associated with infiltration of tissues of affected organs with abundant IgG4-positive cells. We propose expanded diagnostic criteria for AIP with a cohort of histologically confirmed AIP. METHODS: We reviewed the pancreatic imaging findings on computed tomography scans, serum IgG4 levels, other organ involvement, and response to steroids in 29 consecutive patients who met histologic criteria for AIP. RESULTS: Computed tomography scans (n = 22) showed diffuse pancreatic enlargement in 6 (27%) patients; the rest had focal enlargement, distinct mass, normal pancreas, or focal acute pancreatitis. Serum IgG4 level was elevated in 15 of 21 (71%) patients, and other organ involvement (eg, intrahepatic biliary strictures) was noted in 11 of 29 (38%) patients. All 17 patients treated with steroids exhibited resolution/marked improvement of pancreatic/extrapancreatic manifestation. On the basis of this experience we propose that diagnosis of AIP can be made in patients with > or =1 of these criteria: (1) diagnostic histology, (2) characteristic imaging on computed tomography and pancreatography with elevated serum IgG4 level, or (3) response to steroid therapy of pancreatic/extrapancreatic manifestations of AIP. Twenty additional patients met expanded diagnostic criteria for AIP, and their demographic and clinical profile was similar to that of the 29 patients meeting histologic criteria. CONCLUSIONS: AIP defined by histological criteria shows a wide spectrum of radiologic features, with characteristic imaging seen only in a minority. Incorporation of additional features into current diagnostic criteria can identify the full spectrum of clinical presentations of AIP.

Adolescent↗
PubMed2006

Abeta-2M-amyloidosis and related bone diseases.

Abeta-2M-amyloidosis is a type of systemic amyloidosis that is specifically seen in patients with chronic kidney diseases. The precursor protein of Abeta-2M-amyloid fibril is beta2-microglobulin, and its elevated serum level is the main cause of Abeta-2M-amyloidosis in patients with kidney failure. However, the precise mechanism of Abeta-2M-amyloidogenesis remains unclear. In vitro analyses of Abeta-2M amyloidogenesis are still being actively conducted. Osteolytic lesions are often found around synovial membrane with Abeta-2M-amyloid deposition. Both evident osteoclastogenesis and active osteoclastic bone resorption are found, while osteoblastic bone formation is absent in the lesion most likely associated with the inflammation caused by infiltrating macrophages/monocytes into Abeta-2M-amyloid deposition. The precise cell biological mechanism of this inflammatory change is unknown. Further studies are needed to establish specific treatments against this as yet unsolved problem with long-term dialysis therapy.

Amyloid↗
PubMed2006

Computer-aided nodule detection on digital chest radiography: validation test on consecutive T1 cases of resectable lung cancer.

PURPOSE: To evaluate the usefulness of a commercially available computer-assisted diagnosis (CAD) system on operable T1 cases of lung cancer by use of digital chest radiography equipment. MATERIALS AND METHODS: Fifty consecutive patients underwent surgery for primary lung cancer, and 50 normal cases were selected. All cancer cases were histopathologically confirmed T1 cases. All normal individuals were selected on the basis of chest computed tomography (CT) confirmation and were matched with cancer cases in terms of age and gender distributions. All chest radiographs were obtained with one computed radiography or two flat-panel detector systems. Eight radiologists (four chest radiologists and four residents) participated in observer tests and interpreted soft copy images by using an exclusive display system without and with CAD output. When radiologists diagnosed cases as positives, the locations of lesions were recorded on hard copies. The observers' performance was evaluated by receiver operating characteristic analysis. RESULTS: The overall detectability of lung cancer cases with CAD system was 74% (37/50), and the false-positive rate was 2.28 (114/50) false positives per case for normal cases. The mean A(z) value increased significantly from 0.896 without CAD output to 0.923 with CAD output (P = 0.018). The main cause of the improvement in performance is attributable to changes from false negatives without CAD to true positives with CAD (19/31, 61%). Moreover, improvement in the location of the tumor was observed in 1.5 cases, on average, for radiology residents. CONCLUSION: This CAD system for digital chest radiographs is useful in assisting radiologists in the detection of early resectable lung cancer.

Adult↗
PubMed2006

Pulmonary lesions associated with visceral larva migrans due to Ascaris suum or Toxocara canis: imaging of six cases.

OBJECTIVE: The objective of our study was to evaluate chest radiographic and CT findings of patients with pulmonary lesions associated with visceral larva migrans due to Ascaris suum or Toxocara canis. CT investigation was focused on the location, size, contour, and internal features of the lesions; migration of lesions; mediastinal lymphadenopathy; and pleural effusion. CONCLUSION: Pulmonary visceral larva migrans appears on CT as multifocal subpleural nodules with halo or ground-glass opacities and ill-defined margins.

Adult↗
PubMed2005

Comparison of 18FDG-PET with 99mTc-HMDP scintigraphy for the detection of bone metastases in patients with breast cancer.

OBJECTIVE: Bone is one of the most common sites of metastasis in breast cancer patients. Although bone scintigraphy is widely used to detect metastatic breast cancer, the usefulness of 18FDG-PET for detecting bone metastasis has not been clearly evaluated. The purpose of this study was to compare the diagnostic accuracy of 18FDG-PET with bone scintigraphy in detecting bone metastasis in breast cancer patients. METHODS: Forty-four women aged 35 to 81 years (mean, 56 years) with breast cancer were examined in this study. Both 18FDG-PET and bone scintigraphy were performed for each patient with 0-69 day intervals (mean, 11.5 days). The results of each image interpretation were compared retrospectively. Whole-body bones were classified into 9 anatomical regions. Metastases were confirmed at 45/187 regions in 14 patients by bone biopsy or clinical follow-up including other imaging techniques for a period of at least 6 months afterwards. RESULTS: On a region basis, the sensitivity, specificity, and accuracy of 18FDG-PET were 84%, 99% and 95%, respectively. Although these results were comparable to those of bone scintigraphy, the combination of 18FDG-PET and bone scintigraphy improved the sensitivity (98%) and accuracy (97%) of detection. False negative lesions of bone scintigraphy were mostly bone marrow metastases and those of 18FDG-PET were mostly osteoblastic metastases. 18FDG-PET was superior to bone scintigraphy in the detection of osteolytic lesions (92% vs. 73%), but inferior in the detection of osteoblastic lesions (74% vs. 95%). CONCLUSIONS: This study shows that 18FDG-PET tends to be superior to bone scintigraphy in the detection of osteolytic lesions, but inferior in the detection of osteoblastic lesions. 18FDG-PET should play a complementary role in detecting bone metastasis with bone scintigraphy.

Adult↗
PubMed2005

Multifocal nodular lymphoid hyperplasia of the lung.

Nodular lymphoid hyperplasia (NLH) is one of the pulmonary lymphoproliferative disorders, and was initially described as pseudolymphoma. However, reports focusing on CT findings of NLH of the lung have been rare. We report a case of a pulmonary NLH in a 49-year-old woman who showed multiple pulmonary nodules on HRCT and was misdiagnosed preoperatively with adenocarcinoma on the basis of transthoracic cytology. A final diagnosis of NLH was made on postoperative histologic examination.

Female↗
PubMed2005

Gorham's disease of the chest wall: CT and MR characteristics.

We report a case of Gorham's disease of the chest wall in a 29-year-old man. A chest radiograph showed osteolysis of the left first, second, and third ribs. CT and MR images revealed a soft tissue mass around the affected ribs. The mass presented as having heterogeneous high signal intensity on T2-weighted MR images, and it showed minimal enhancement on contrast-enhanced MR images. A histologic specimen obtained by incisional biopsy from the left third rib revealed proliferation of lymphangiomatous tissue in the bone marrow. A diagnosis of Gorham's disease was made based on these clinical, radiologic, and histologic findings.

Adult↗
PubMed2005

shk1-D, a dwarf Arabidopsis mutant caused by activation of the CYP72C1 gene, has altered brassinosteroid levels.

Brassinosteroids (BRs) are plant steroidal hormones that regulate plant growth and development. An Arabidopsis dwarf mutant, shrink1-D (shk1-D), was isolated and the phenotype was shown to be caused by activation of the CYP72C1 gene. CYP72C1 is a member of the cytochrome P450 monooxygenase gene family similar to BAS1/CYP734A1 that regulates BR inactivation. shk1-D has short hypocotyls in both light and dark, and short petioles and siliques. The seeds are also shortened along the longitudinal axis indicating CYP72C1 controls cell elongation. The expression of CPD, TCH4 and BAS1 were altered in CYP72C1 overexpression transgenic lines and endogenous levels of castasterone, 6-deoxocastasterone and 6-deoxotyphasterol were also altered. Unlike BAS1/CYP734A1 the expression of CYP72C1 was not changed by application of exogenous brassinolide. We propose that CYP72C1 controls BR homeostasis by modulating the concentration of BRs.

Amino Acid Sequence↗
PubMed2005

[Successful treatment with CHOP therapy for progressive of primary macroglobulinemia without further increase of serum IgM].

A 61-year-old man with primary macroglobulinemia (PMG) had been followed without any treatment as he had no apparent manifestations. After 1 year and 3 months, he was admitted to our hospital with a fever. No signs or symptoms of infection and no progressive increase of serum IgM levels was observed. Non-Hodgkin's lymphoma was not additionally found. Fever without infection, elevated serum LDH level and further enlargement of the spleen compelled us to diagnose his condition as deterioration of the PMG. An immediate fall in his temperature and serum IgM levels was observed after CHOP therapy. Effective therapy must be discussed in the deterioration of this type of disease.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2005

[Diffuse large B-cell lymphoma with strongly positive MIB-1 stain and clinical features resembling Burkitt lymphoma].

A 62-year-old woman was admitted to our hospital because of gastric mucosal bleeding. Gastroendoscopy revealed a gastric tumor which was diagnosed from the biopsied specimen as diffuse large B-cell lymphoma (DLBCL). Lymphoma cells had infiltrated the bone marrow showed morphological features resembling Burkitt lymphoma (BL). Nearly 100% of the cells in the bone marrow were positive for MIB-1 immunostaining. The chromosomal study was normal. Surface marker analysis disclosed that the cells were positive for CD10, CD19, CD20 and CD25. As lymphoma cells had infiltrated the central nervous system, combined chemotherapy was performed accompanied with intrathecal administration of anticancer drugs. Although transient improvement was observed, the patient died of the advanced disease three months after admission. As we have shown here, there are some cases of DLBCL with immunohistochemical features resembling BL. Further consideration about the appropriate chemotherapy program for this type of disease might be necessary.

Antineoplastic Combined Chemotherapy Protocols↗