Biomedical subjects

T Masumoto

Publications and source records attributed to T Masumoto.

At least 19 recordsLinked to original sources

PubMed2003

Neuro-Behçet's disease: analysis of apparent diffusion coefficients.

Little is known about the diffusion properties of brain lesions in neuro-Behçet's disease (NBD). We looked at 19 NBD lesions (13 active, six chronic) in six patients, using diffusion-weighted MRI (DWI). We calculated the apparent diffusion coefficients (ADC) of the lesions and compared them with normal contralateral brain, expressing this ratio as relative ADC (rADC). The rADC was 1.29+/-0.33 in active and 1.44+/-0.47 in chronic lesions, i.e., significantly higher than in the control regions. Increased diffusivity in both active and chronic phases in NBD is different from the pattern in ischaemic infarcts, so that ADC analysis might be helpful for differentiating between these conditions.

Adolescent↗

PubMed2003

MR imaging of postischemic neuronal death in the substantia nigra and thalamus following middle cerebral artery occlusion in rats.

The goal of this study was to investigate apparent diffusion coefficient (ADC) and T(2) relaxation time (T(2)) in the substantia nigra and thalamus after middle cerebral artery occlusion in rats. In the substantia nigra ipsilateral to infarct, ADC was significantly lower and T(2) was significantly higher on the third and fourth days, but they did not change significantly on the first, second, eighth and 15th days. In the ipsilateral thalamus, ADC and T(2) did not change significantly between the first and fourth days, but were significantly lower on the eighth and 15th days. This combination of MR findings suggested that secondary degeneration in the thalamus was different from that in the substantia nigra.

Animals↗

PubMed2003

A phase I study of S-1 combined with weekly cisplatin for metastatic gastric cancer in an outpatient setting.

A dose-escalation study was conducted for patients with metastatic gastric cancer to determine the recommended dose of weekly intravenous (i.v.) cisplatin combined with a fixed dose of a new oral dihydropyrimidine dehydrogenase-inhibitory fluoropyrimidine, S-1, on an outpatient basis. Secondary endpoints were to define the toxicity profile and to determine tumour responses. S-1 was fixed at a dose of 70 mg/m(2)/day and was administered for 2 weeks followed by a 1-week rest. Three dose levels of cisplatin (10, 15 and 20 mg/m(2)) were studied. Cisplatin was infused over 30 min on days 1 and 8. 20 patients were enrolled. No dose-limiting toxicities (DLTs) were recorded during the administration of cisplatin up to 20 mg/m(2), except for grade 3 diarrhoea and stomatitis in one patient at dose level 3. No grade 4 adverse events occurred. However, grade 2 gastrointestinal adverse reactions, such as nausea and anorexia, were seen in 7 of 13 patients at dose level 3 within the first two treatment cycles. This was determined to be the maximum acceptable level that would not negate the advantages observed with use of an oral drug such as S-1. An objective tumour response was seen at all dose levels, and the overall response rate in the 18 patients evaluated was 61%. A higher response rate of 78% was observed in 9 patients who had received no prior chemotherapy. Oral S-1 with weekly cisplatin is a feasible and promising combination regimen that is appropriate for an outpatient setting. A randomised phase II study comparing this combination with S-1 alone in chemo-nai;ve patients is warranted.

Adult↗

PubMed2002

Two-dimensional thick-slice MR digital subtraction angiography in the assessment of small to medium-size intracranial arteriovenous malformations.

Assessment of intracranial arteriovenous malformations (AVMs) by conventional catheter angiography carries risks; moreover, this invasive procedure is often repeated for follow-up. We investigated the clinical applicability of two-dimensional thick-slice, contrast-enhanced magnetic resonance digital subtraction angiography (2D MRDSA) with high temporal resolution in the assessment of AVMs. We performed 78 2D MRDSA studies of treated or untreated small to medium-size AVMs on a 1.5 tesla imager. Two observers independently evaluated demonstration of nidus flow void on T2-weighted images and each component of the AVM on 2D MRDSA employing a three-point grading scale. In 55 patients with AVMs, the mean ratings of nidus flow voids, feeding vessels, nidi, draining vessels and early venous filling on MRI were 2.8, 2.4, 2.6, 2.8 and 2.8, respectively. sensitivity, specificity, positive and negative predictive values for an AVM using 2D MRDSA were 87, 100, 100 and 78%, respectively and for nidus flow voids on T2-weighted images 80, 91, 96 and 66%, respectively. 2D MRDSA can thus demonstrate haemodynamic features of AVMs. It can be employed as a less invasive, dynamic angiographic tool for follow-up of AVMs previously delineated by catheter angiography.

Adult↗

PubMed2002

Diffusion-weighted magnetic resonance imaging of dural sinus thrombosis.

Magnetic resonance imaging (MRI) is useful to diagnose dural sinus thrombosis. However, the representative appearance of dural sinus thrombosis on diffusion-weighted MRI has not been established. This study was aimed at determining whether cytotoxic or vasogenic edema is more predominant in the affected cerebral parenchyma and assessing the time courses and prognosis of dural sinus thrombosis lesion. The studies on sixteen patients with dural sinus thrombosis who underwent diffusion-weighted MRI were retrospectively reviewed. The diagnosis was confirmed by digital subtraction angiography in 11 patients and magnetic resonance angiography in five patients. Diffusion-weighted images with echo-planar imaging were obtained using two or three b values, with the highest b value of up to 1,000 s/mm(2). A region of interest was placed on an area of abnormal signal intensity to calculate apparent diffusion coefficients (ADCs). Nine of the 16 patients had lesions with an increased ADC, whereas, three of these nine patients also had lesions with a decreased ADC. Among 11 patients who underwent initial MRI within 7 days of their last episode, eight had lesions with an increased ADC, of whom three had lesions mixed with both decreased and increased ADC areas. Follow-up studies of these three patients revealed the development of hemorrhagic infarction in two and subcortical hemorrhage in one. Vasogenic edema develops more predominantly and earlier in dural sinus thrombosis, though cytotoxic edema was also associated with the pathological changes in the early phase. Decrease of ADC value is presumed to reflect severe pathological conditions and indicate possible future development of infarction or hemorrhage.

Adult↗

PubMed2002

The value of the chest computed tomography halo sign in the diagnosis of invasive pulmonary aspergillosis. An autopsy-based retrospective study of 48 patients.

To evaluate the diagnostic value of a halo on computed tomography (CT) in the diagnosis of invasive pulmonary aspergillosis (IPA), we retrospectively reviewed chest CT scans and autopsy reports for patients who had been admitted to our hospitals for the treatment of hematological malignancy. Pulmonary complications were suspected in all patients and chest CT scans were taken within a month of death. We examined the association between autopsy and CT findings in 48 patients who were diagnosed as IPA (n = 17), candidosis (n = 4), zygomycosis (n = 2), infiltration of hematological malignancy (n = 12), bacterial pneumonia (n = 6), cytomegalovirus pneumonia (n = 2), pulmonary hemorrhage (n = 2), or pulmonary congestion (n = 1). Patients with IPA showed a variety of CT findings, including halo (n = 13), nodules (n = 14), granular shadows (n = 3), masses (n = 6), consolidations (n = 9), wedge-shaped consolidations (n = 1), and cavitation (n = 2). In contrast, 0, 11 and two of the 31 patients without IPA showed halo, nodules and masses, respectively. These signs were more frequently observed in IPA patients than in non-IPA patients. The CT halo, especially, seemed to be specific for IPA in hospitalized neutropenic patients with hematological malignancies who developed antibiotic-resistant fever. For CT findings other than these three signs, there were no significant differences between IPA- and non-IPA patients.

Adolescent↗

PubMed2002

Hemorrhagic brain metastases with high signal intensity on diffusion-weighted MR images. A case report.

Diffusion-weighted MR imaging has been applicable to the differential diagnosis of abscesses and necrotic or cystic brain tumors. However, restricted water diffusion is not necessarily specific for brain abscess. We describe ring-enhancing metastases of lung carcinoma characterized by high signal intensity on diffusion-weighted MR images. The signal pattern probably reflected intralesional hemorrhage. The present report adds to the growing literature regarding the differential diagnosis of ring-enhancing brain lesions.

Brain Abscess↗

PubMed2001

Peripheral blood T-cell responses to pyruvate dehydrogenase complex in primary biliary cirrhosis: role of antigen-presenting dendritic cells.

Patients with primary biliary cirrhosis (PBC) are usually characterized by the presence of antibody to pyruvate dehydrogenase complex (PDC) in the sera and PDC-specific T cells in the liver. However, most of the patients with PBC do not show peripheral blood T cells response to PDC. In this study, we re-evaluated the peripheral blood T cell responses to PDC in PBC using antigen-presenting dendritic cells (DCs). Twenty-four patients with PBC (AMA-positive: 16; AMA-negative: 8) and 13 normal controls were enrolled in the study. Peripheral blood mononuclear cells (PBMC) and highly enriched populations of T cells were stimulated with either only PDC or DCs plus PDC or PDC-pulsed DC plus PDC. Antibodies to different components of PDC were estimated by an immunoblotting technique. PBMC from only one out of ten AMA-positive PBC patients proliferated when cultured with only PDC. However, peripheral blood T cells from ten out of ten AMA-positive PBC patients and three out of ten AMA-negative PBC patients, but none of the five normal controls showed PDC-specific proliferation when cultured with PDC-pulsed DCs. Two of these three AMA-negative PBC patients, although negative for AMA, were positive for antibodies to other components of PDC. PDC-specific T cells are present in the peripheral blood from most of the patients with PBC. This is the first report on the effectiveness of antigen-pulsed DCs for the elucidation of autoantigen-specific immune response in human autoimmune diseases.

Adult↗

PubMed2001

Relationships among facial type, buccolingual molar inclination, and cortical bone thickness of the mandible.

The purpose of this study was to evaluate the relationships between different facial types, and both the buccolingual molar inclination and cortical bone thickness of the mandible. The material consisted of 31 dry skulls of modern Japanese males from the Museum of the University of Tokyo. They all demonstrated normal occlusion with minimal dental discrepancy, and without crossbite or facial asymmetry. The buccolingual inclination of the second molar (M2) in the long-faced subjects was significantly smaller than the same dimension in the average- and short-faced subjects. It was found that the teeth of long-faced subjects were more lingually inclined than those of the short-faced subjects. The cortical bone thickness of the first molar (M1) and M2 sections was thicker in short-faced subjects than in average- and long-faced subjects. The results of this study provide evidence that a significant, but complex relationship exists between structures of the mandibular body and facial types. The morphological features that relate to masticatory function and facial types are associated with the cortical bone thickness of the mandibular body, and the buccolingual inclination of the first and second molars.

Adolescent↗

PubMed2001

An autopsy case of primary biliary cirrhosis with severe interstitial pneumonia.

A 74-year-old woman was admitted to our hospital because of interstitial pneumonia. She had a 14-year history of primary biliary cirrhosis (PBC) diagnosed histologically, with a positive test for anti-mitochondrial antibodies and elevated biliary enzyme activity. She also had a 7-year history of rheumatoid arthritis and a 26-year history of Sjögren's syndrome. Though the symptoms of these complications improved, the interstitial pneumonia deteriorated very quickly and the patient died of respiratory failure due to acute exacerbation of interstitial pneumonia when the activity of PBC decreased. We report this case because it is relatively rare for PBC to be complicated by severe interstitial pneumonia, and it may offer insight into the etiology of these diseases.

Aged↗

PubMed2000

TT virus infection among renal transplant recipients.

To clarify the prevalence of TT virus (TTV) infection in renal transplant recipients and to estimate the role of TTV in patients with post-transplant liver function abnormalities, TTV-DNA of 47 renal transplant recipients was screened by polymerase chain reaction (PCR) according to a method described by Okamoto et al. before and after the renal transplantation. One of them was positive for hepatitis B surface antigen (HBsAg), one was positive for anti-hepatitis C virus (HCV) and other 45 were negative for both HBsAg and anti-HCV. TTV-DNA was detected in 22 of 47 patients before renal transplantation, and nine became positive after transplantation. All 47 patients showed a normal level of ALT before transplantation. Three of nine (33%) who became positive for TTV-DNA after transplantation and three of 16 (19%) who were negative for TTV-DNA before and after transplantation showed transient elevation of ALT. These results indicate that TTV was highly prevalent among renal transplant recipients, but a clear association between TTV and post-transplant liver function abnormality was not found.

Journal Article↗

PubMed2000

Contrast-enhanced magnetic resonance imaging of the cranial nerves in patients with acoustic schwannoma: correlation with surgical findings.

Eighteen patients with acoustic schwannoma were examined on a 1.5-T magnetic resonance imaging (MRI) unit with precontrast and postcontrast T1-weighted spin-echo sequences. Each abnormality was assessed in terms of the size, location, extensions and signal intensity of the lesions. If a nerve was enhanced and was involved by the tumor around the fundus of the internal auditory canal (IAC), the nerve was interpreted to be the originating nerve. The postcontrast T1-weighted images revealed enhanced masses of the cerebellopontine angle and/or the IAC in all cases. In 11 of the 19 operated patients with shwannomas, the site of tumor origin (or origin nerve) was confirmed by surgery. In 2 of the 11 cases (18%), surgical findings coincided with the T1-weighted image findings. Facial nerve enhancement on the ipsilateral side of the tumor was noted in 10 cases (53%) and the contralateral facial nerve enhancement was demonstrated in 7 (70%). The enhancement of facial nerve associated with acoustic schwannoma was not correlated to the degree of nerve compression by the tumor. These results demonstrate that it was possible, although infrequent, to predict the site of origin of acoustic schwannoma before surgery in some patients. Improvement of the imaging matrix or multiplanar reconstruction techniques with three-dimensional data acquisition may make it possible to overcome the limitations of MRI.

Adult↗

PubMed2000

Temporal changes of the apparent diffusion coefficients of water and metabolites in rats with hemispheric infarction: experimental study of transhemispheric diaschisis in the contralateral hemisphere at 7 tesla.

The purpose of the present study was to clarify the temporal changes of the apparent diffusion coefficients (ADCs) of cerebral metabolites during early focal ischemia using stimulated echo acquisition mode with short echo time at a 7 T magnet to assess the pathophysiology of the reduction in diffusion properties observed both in the ischemic cerebral hemisphere and in the contralateral hemisphere. The ADCs of metabolites in the infarcted hemisphere 1 hour and 3 hours after the onset of ischemia decreased with 25% and 29% for choline containing compounds (Cho), 16% and 26% for creatine and phosphocreatine (Cre), and 19% and 19% for N-acetylaspartate (NAA), respectively, compared with the ADC values 2 hours later in the contralateral hemisphere. There were decreases in the ADC of Cho, Cre, and NAA with 21%, 7%, and 18% 8 hours later, respectively, in the noninfarcted hemisphere, which suggested transhemispheric diaschisis in rats with focal cerebral ischemia. The present study proposed that the diffusion characteristics of the brain metabolites might offer new insights into circulatory and metabolic alteration in the cerebral intracellular circumstance.

Animals↗

PubMed2000

Computed tomographic scan of the chest, latex agglutination test and plasma (1AE3)-beta-D-glucan assay in early diagnosis of invasive pulmonary aspergillosis: a prospective study of 215 patients.

BACKGROUND AND OBJECTIVES: Blood and radiologic tests are frequently used for diagnosis of invasive pulmonary aspergillosis, but it remains unknown which is more useful for its early diagnosis. Aim of the study was to compare usefulness of computed tomographic (CT) scan of chest, latex agglutination (LA) test and determination of plasma (1-->3)-beta-D-glucan (BDG) levels for early diagnosis of invasive pulmonary aspergillosis (IPA). DESIGN AND METHODS: We treated 215 consecutive patients who underwent cytotoxic chemotherapy. From initiation of chemotherapy until death or discharge, blood samples were taken weekly and subjected to LA and BDG tests. We performed chest CT scans when patients had any signs of pulmonary infection or an antibiotic-resistant fever. RESULTS: Of the 215 patients, 30 (14. 0%) were diagnosed as having IPA. In sixteen cases the diagnosis was definite and in 14 it was suspected. In patient-based analysis, sensitivities of LA and BDG were 44% and 63%, respectively. Sensitivity tended to be lower in patients with IPA localized to the lung than those with disseminated invasive aspergillosis. Specificities were 93% and 74%, respectively. Either a halo or an air-crescent was observed in 7 of the 16 patients with IPA, and all of the IPA patients showed some abnormal signs on chest CT scans. On average, CT scan signs preceded a positive LA test by 7.1 days and a positive BDG assay by 11.5 days. In 6 of the 11 patients who became positive for either LA or BDG assay, CT scan signs preceded the positive results by more than seven days. INTERPRETATION AND CONCLUSIONS: Chest CT scan is more beneficial than the blood tests and X-ray for early diagnosis of IPA.

Adjuvants, Immunologic↗

PubMed1999

Pseudomyxoma retroperitonei.

We report a rare case of pseudomyxoma retroperitonei in a 58-year-old woman with a past history of severe appendicitis. The imaging showed a multicystic mass similar to pseudomyxoma peritonei, but the tumor was located in the retroperitoneal space.

Diagnosis, Differential↗

PubMed1999

Mechanism of action of vaccine therapy in murine hepatitis B virus carriers: vaccine-induced activation of antigen presenting dendritic cells.

BACKGROUND/AIMS: Vaccine therapy in which vaccine containing hepatitis B surface antigen (HBsAg) is injected has shown therapeutic activity (vaccine therapy) in some human and murine chronic hepatitis B virus (HBV)-carriers. Using HBV-transgenic mice (HBV-Tg), an animal model of the HBV-carrier state, the mechanism underlying the antiviral and immune modulatory capacity of vaccine therapy was studied. METHODS: Placebo-controlled, double-blind trials of vaccine therapy were conducted in HBV-Tg; some HBV-Tg responded to the therapy, whereas others were non-responders. The titers of HBV-markers, the functions of lymphocytes and antigen presenting dendritic cells were compared between vaccine responders and vaccine non-responders. RESULTS: The prevaccinated titers of HBsAg, hepatitis B e-antigen (HBeAg), HBV DNA and the responses of lymphocytes to polyclonal mitogens were almost unchanged between responders and non-responders, but the levels of proliferation of HBsAg-specific lymphocytes from non-responders was significantly lower than responders (p<0.05). The capacity of dendritic cells to induce proliferation of T cells and production of antibody to HBsAg (anti-HBs) was significantly higher in responders compared with non-responders (p<0.05). Injection with HBsAg resulted in upregulation of MHC class II and CD86 antigens (p<0.05) on dendritic cells and increased production of IL-12, IL-2 and TNF-alpha in cultures (p<0.05) in vaccine responders but not in non-responders. CONCLUSIONS: The activation of dendritic cells following injection with vaccine containing HBsAg is the vital factor underlying the therapeutic potentiality of vaccine therapy in HBV carriers.

Animals↗

PubMed1999

Dendritic cells with immature phenotype and defective function in the peripheral blood from patients with hepatocellular carcinoma.

BACKGROUND/AIMS: Defects and dysfunctions in antigen-presenting dendritic cells have been shown during carcinogenesis. The phenotype and function of dendritic cells have been studied in patients with hepatocellular carcinoma to explore the possibility of dendritic cell-based immune therapy in hepatocellular carcinoma. METHODS: The stimulatory capacity of dendritic cells in allogenic mixed leukocytes reaction, the expression of surface makers on dendritic cells, the production of cytokines and nitric oxide by dendritic cells and the levels of maturation of dendritic cells from 17 patients with hepatocellular carcinoma, 10 patients with liver cirrhosis and 10 normal controls were compared. RESULT: Dendritic cells from hepatocellular carcinoma had significantly lower capacity to stimulate allogenic T cells in allogenic mixed leukocytes reaction compared with dendritic cells from liver cirrhosis and normal controls (p<0.05). Dendritic cells from hepatocellular carcinoma expressed significantly lower levels of HLA DR and induced decreased amounts of interleukin-12 compared with dendritic cells from normal controls (p<0.05). On the other hand, dendritic cells from hepatocellular carcinoma produced significantly higher levels of nitric oxide and tumor necrosis factor-a compared with dendritic cells from liver cirrhosis and normal controls (p<0.05). The uptake of fluorescein isothiocyanate-labeled dextran revealed an immature phenotype of dendritic cells from hepatocellular carcinoma compared with dendritic cells from liver cirrhosis (p<0.05). CONCLUSION: The results of this study on the function of dendritic cells in hepatocellular carcinoma, and the prevalence of immature dendritic cells in hepatocellular carcinoma in the microenvironment of high levels of inflammatory cytokines indicate a specific defect of dendritic cell maturation during hepatocarcinogenesis. These data show that induction of dendritic cell maturation might be an approach to dendritic cell-based immune therapy during hepatocellular carcinoma.

Biomarkers↗

PubMed1999

Potent synergistic effect of sho-saiko-to, a herbal medicine, during vaccine therapy in a murine model of hepatitis B virus carrier.

BACKGROUND: Traditional herbal medicine, sho-saiko-to (TJ-9), improves subjective symptoms, and a recently developed vaccine therapy reduces the viral replication in some chronic hepatitis B virus (HBV)-carriers. The study presented here considers the impact of a combination of vaccine therapy and TJ-9 and the mechanism underlying the therapeutic effect of TJ-9. MATERIALS AND METHODS: HBV-transgenic mice (HBV-Tg) expressing similar levels of HBV-related antigens and HBV DNA were used as an animal model of HBV-carrier state, and were assigned to receive either a TJ-9-enriched diet or a monthly injection of vaccine containing hepatitis B surface antigen (HBsAg), or both, for 12 consecutive months. RESULTS: Twelve months after starting the therapy, 9% (1 of 11), 61% (11 of 18), and 100% (10 of 10) of HBV-Tg receiving only the TJ-9-treatment, only the monthly vaccine, and both the TJ-9 and vaccine, respectively, responded to therapy and became completely negative for HBsAg. Spleen lymphocytes and antigen presenting cells (APC) from TJ-9-treated HBV-Tg produced significantly higher levels of IgM, IgG and antibodies to keyhole limpet hemocyanin (KLH) and showed significantly higher stimulatory capacity in allogenic mixed leukocyte reaction (MLR) compared with the spleen cells and APC from HBV-Tg receiving normal diet without TJ-9 (P < 0.05). CONCLUSION: These data confirm the therapeutic role of TJ-9 during HBV infection and inspire optimism of a widespread use of TJ-9 during immune therapies.

Adjuvants, Immunologic↗