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Biomedical subjects

T Fujimoto

Publications and source records attributed to T Fujimoto.

At least 163 records · Page 9Linked to original sources

18F-FDG PET imaging of muscle activity in runners.

UNLABELLED: PET with three-dimensional data acquisition using 18F-fluorodeoxyglucose (FDG) was applied to evaluate skeletal muscle activity in runners. METHODS: Seven healthy adult male volunteers were studied. They ran for a total of 35 min, 15 min before and 20 min after intravenous injection of FDG. Another 7 adult male control subjects were also examined at rest. Images obtained through a set of whole-body PET scans were analyzed. Regions of interest (ROIs) were manually drawn on images of muscles of both thighs, legs and feet, and the standardized uptake ratio (SUR) and total radioactivity distribution (TRD) for each region were calculated. RESULTS: The work load was below the anaerobic threshold. SUR of foot, leg and thigh were low at rest but during running increased 5.19, 4.30 and 1.74 times, respectively. The SUR of posterior-to- anterior compartment of the leg was 1.1+/-0.1 at rest and 1.6+/-0.5 (P < 0.01) during running. The laterality index of both SUR and TRD changed significantly only in the foot of the dominant side during running. TRD of the leg, less than half that of the thigh at rest, became equivalent to that of the thigh during running. TRD of the foot did not change significantly. CONCLUSION: Sole muscles showed highest metabolic activation per unit volume during running, which was higher in the dominant side. Comparison of whole muscle activity during running indicated the highest metabolic activation was in the posterior compartment of the leg, whereas thigh muscles showed relatively little changes during running. Our data indicate that whole-body FDG PET, especially three-dimensional data acquisition, is a useful tool for the investigation of muscular activity during exercise.

Adult↗

Frequent aberration of FHIT gene expression in acute leukemias.

We analyzed the mRNA expression of the FHIT gene by reverse transcription-PCR (RT-PCR) in 54 cases of acute lymphoblastic leukemia (ALL; 11 cases of T-cell ALL [T-ALL] and 43 cases of non-T-ALL) and 40 cases of acute myeloid leukemia (AML). In 46% of the ALL cases and 55% of the AML cases, FHIT expression was absent or markedly decreased. Only abnormal short bands were detected in 30% of the ALL cases and 5% of the AML cases. Eighteen of 19 abnormal transcripts had the same fusion of exons 2-7, and all lacked the starting codon in exon 5. No obvious normal-sized PCR products were detected in cases exhibiting abnormal transcripts. These findings suggest that the expression of functional FHIT protein was lost in the majority of ALL (76%) and AML (60%) cases. Differential quantitative PCR of exons 3-9 of the FHIT gene and RT-PCR of the PTPRG gene, which is centromeric to the FHIT gene, showed the presence of the target sequences. Fluorescence in situ hybridization analysis using probes covering exons 5 and 8 revealed no difference in the signal patterns between leukemia and normal cells, showing one or two signal doublets in more than 90% of nuclei, and indicated that gross segments of the FHIT gene were not homozygously deleted in these cases. A small number of transcripts with an aberrant fusion between exons 2 and 7 were detected by RT-PCR in the bone marrow cells from four healthy individuals. Granulocytes, lymphocytes, and monocytes in the bone marrow cells of a healthy individual contained transcripts with the same fusion. This unique fusion of exons 2 and 7 might be preferentially seen in either neoplastic or normal hematopoietic cells, regardless of their lineage. The finding that FHIT expression was abolished in the majority of leukemia cases might support the hypothesis that the FHIT gene acts as a tumor suppressor, at least in leukemia.

Acid Anhydride Hydrolases↗

An atypical PKC directly associates and colocalizes at the epithelial tight junction with ASIP, a mammalian homologue of Caenorhabditis elegans polarity protein PAR-3.

Cell polarity is fundamental to differentiation and function of most cells. Studies in mammalian epithelial cells have revealed that the establishment and maintenance of cell polarity depends upon cell adhesion, signaling networks, the cytoskeleton, and protein transport. Atypical protein kinase C (PKC) isotypes PKCzeta and PKClambda have been implicated in signaling through lipid metabolites including phosphatidylinositol 3-phosphates, but their physiological role remains elusive. In the present study we report the identification of a protein, ASIP (atypical PKC isotype-specific interacting protein), that binds to aPKCs, and show that it colocalizes with PKClambda to the cell junctional complex in cultured epithelial MDCKII cells and rat intestinal epithelia. In addition, immunoelectron microscopy revealed that ASIP localizes to tight junctions in intestinal epithelial cells. Furthermore, ASIP shows significant sequence similarity to Caenorhabditis elegans PAR-3. PAR-3 protein is localized to the anterior periphery of the one-cell embryo, and is required for the establishment of cell polarity in early embryos. ASIP and PAR-3 share three PDZ domains, and can both bind to aPKCs. Taken together, our results suggest a role for a protein complex containing ASIP and aPKC in the establishment and/or maintenance of epithelial cell polarity. The evolutionary conservation of the protein complex and its asymmetric distribution in polarized cells from worm embryo to mammalian-differentiated cells may mean that the complex functions generally in the organization of cellular asymmetry.

3T3 Cells↗

Mutations in the E-domain of RAR portion of the PML/RAR chimeric gene may confer clinical resistance to all-trans retinoic acid in acute promyelocytic leukemia.

The binding of all-trans retinoic acid (ATRA) to the ligand-binding region in the E-domain of retinoic acid receptor-alpha modifies the transcriptional activity of RARalpha protein. ATRA probably induces differentiation of acute promyelocytic leukemia (APL) cells by binding to the E-domain of the RARalpha portion (RARalpha /E-domain) of PML/RARalpha chimeric protein. Therefore, molecular alteration in the RARalpha /E-domain of the chimeric gene is one mechanism by which patients with APL may acquire resistance to ATRA therapy. In this study using reverse transcription-polymerase chain reaction and single-strand conformation polymorphism, DNA segments amplified from the RARalpha /E-domain in fresh APL cells of 23 APL patients (8 males and 15 females from 4 to 76 years of age) were screened for mutations. Of those patients, 3 patients (1 with de novo and 2 with relapse) had clinical resistance to ATRA therapy. We found mutations in the RARalpha /E-domain of PML/RARalpha chimeric gene exclusively in the 2 patients who exhibited ATRA-resistance at relapse, whereas the mutations were not detected at their initial onset. Interestingly, these patients received a prolonged or intermittent administration of ATRA before relapse with ATRA-resistance. The mutations lead to the change of amino acid in the ligand-binding region of RARalpha /E-domain, Arg272Gln, or Met297Leu according to the amino acid sequence of RARalpha, respectively. Further study demonstrated that the in vitro ligand-dependent transcriptional activity of the mutant PML/RARalpha protein was significantly decreased as compared with that of wild-type PML/RARalpha. These findings suggest that mutations in the RARalpha /E-domain of the PML/RARalpha chimeric gene may confer clinical resistance to ATRA therapy in patients with APL.

Adolescent↗

High-performance liquid chromatographic analysis of aminoglycoside antibiotics.

A simple precolumn derivatisation method for the determination of aminoglycoside antibiotics (AGs) is described. The stability of the o-phthalaldehyde (OPA) derivatives of the AGs obtain using beta-mercaptopropionic acid (beta-MP) was investigated by reversed-phase HPLC. One of the fluorescent derivatives of sisomicin was stable at least for 6 h in 50% methanol under the optimal conditions used (OPA concentration, pH and temperature). When plasma samples spiked with sisomicin were analysed the response was linear in the calibration range of 136-900 micrograms of sisomicin per injected volume (40 microliters). As little as 0.06 micrograms of sisomicin per 1 ml of plasma could be detected with a signal-to-noise ratio > or = 2. The method was also applied to whole blood samples from rabbit after a subcutaneous injection of 1 mg/kg of the AGs using dried blood spots (DBS) on the filter-paper punched discs. The detection of sisomicin and netilmicin in the DBSs on punched discs (10.1 micrograms of whole blood) were 0.053 and 0.50 micrograms per ml of whole blood, respectively (signal-to-noise ratio > or = 2). The method permits a simple collection of blood at the microlitre level and should prove particularly useful for monitoring the AGs in blood at therapeutic levels in geriatric and paediatric patients and could be also used for the preclinical study of the AGs blood levels of a number of mice or rats without killing. An RP-HPLC method using an on-line clean-up procedure for large sample-volume analysis of serum AGs is also described.

Aminoglycosides↗

Endothelial Ca2+ waves preferentially originate at specific loci in caveolin-rich cell edges.

Stimulation of endothelial cells (ECs) with ATP evoked an increase in intracellular Ca2+ concentration ([Ca2+]i). In a single bovine aortic EC, the [Ca2+]i rise started at a specific peripheral locus and propagated throughout the entire cell as a Ca2+ wave. The initiation locus was constant upon repeated stimulation with ATP or other agonists (bradykinin and thrombin). The Ca2+ wave was unaffected by the removal of extracellular Ca2+, demonstrating its dependence on intracellular Ca2+ release. Microinjection of heparin into the cell inhibited the ATP-induced Ca2+ responses, indicating that the Ca2+ wave is at least partly mediated by the inositol 1,4, 5-trisphosphate receptor. Immunofluorescence staining revealed that caveolin, a marker protein for caveolae, is distributed heterogeneously in the cell and that Ca2+ waves preferentially originate at caveolin-rich cell edges. In contrast to caveolin, internalized transferrin and subunits of the clathrin-associated adaptor complexes such as adaptor protein-1 and -2 were diffusely distributed. Disruption of microtubules by Colcemid led to redistribution of caveolin away from the edges into the perinuclear center of the cell, and the ATP-induced [Ca2+]i increase was initiated on the rim of the centralized caveolin. Thus, caveolae may be involved in the initiation of ATP-induced Ca2+ waves in ECs.

Adaptor Protein Complex alpha Subunits↗

Occludin-deficient embryonic stem cells can differentiate into polarized epithelial cells bearing tight junctions.

Occludin is the only known integral membrane protein of tight junctions (TJs), and is now believed to be directly involved in the barrier and fence functions of TJs. Occludin-deficient embryonic stem (ES) cells were generated by targeted disruption of both alleles of the occludin gene. When these cells were subjected to suspension culture, they aggregated to form simple, and then cystic embryoid bodies (EBs) with the same time course as EB formation from wild-type ES cells. Immunofluorescence microscopy and ultrathin section electron microscopy revealed that polarized epithelial (visceral endoderm-like) cells were differentiated to delineate EBs not only from wild-type but also from occludin-deficient ES cells. Freeze fracture analyses indicated no significant differences in number or morphology of TJ strands between wild-type and occludin-deficient epithelial cells. Furthermore, zonula occludens (ZO)-1, a TJ-associated peripheral membrane protein, was still exclusively concentrated at TJ in occludin-deficient epithelial cells. In good agreement with these morphological observations, TJ in occludin-deficient epithelial cells functioned as a primary barrier to the diffusion of a low molecular mass tracer through the paracellular pathway. These findings indicate that there are as yet unidentified TJ integral membrane protein(s) which can form strand structures, recruit ZO-1, and function as a barrier without occludin.

Animals↗

Bcl-2 expression and prognosis of patients with endometrial carcinoma.

Bcl-2 protein inhibits apoptosis, reduces the requirement for growth factors, and thereby extends the survival of cells. Recent findings of Bcl-2 in several solid tumors suggest that it might contribute to the genesis of some types of cancer. Over-expression of Bcl-2 might play a role in carcinogenesis and malignant progression of endometrial carcinoma. The aims of this study were to determine Bcl-2 expression in endometrial carcinoma in relation to other histopathologic prognostic factors, and to test its prognostic significance in patients with endometrial carcinoma. A total of 61 endometrioid-type endometrial carcinomas were immunohistochemically investigated for Bcl-2 expression on cryostat sections. Bcl-2 localization was observed in cytoplasm in 18 tumors, in nucleus in 27 tumors, or in both in 5 tumors. In 11 tumors, Bcl-2 was observed neither in cytoplasm nor in nucleus. There was not a statistically significant relationship between grade of tumor and Bcl-2 expression. Cytoplasmic Bcl-2 became less frequently expressed as the tumor invaded the myometrium deeper (p < 0.025). Retroperitoneal lymph-node dissection was performed in 57 patients. Multiple-regression analysis showed that lymph-vascular space invasion and nuclear expression of Bcl-2 were correlated to pelvic lymph-node metastasis (p < 0.0001 and < 0.05 respectively). Univariate Cox regression analysis revealed that nuclear Bcl-2 expression was associated with shorter survival (p < 0.05) than that of patients with cytoplasmic Bcl-2 expression. Pelvic node metastasis was a significant prognostic factor for patients who underwent systematic retroperitoneal lymph-node dissection. Cox multivariate-regression analysis revealed that pelvic node metastasis and cervical invasion were the most important prognostic factors in this series of patients. When the analysis was made after exclusion of pelvic node metastasis, histologic grade (hazard ratio = 2.4), cervical invasion (hazard ratio = 3.7) and nuclear Bcl-2 expression (hazard ratio = 11.5) were shown to be significant predictors of survival of the patients. These results indicate that aberrant Bcl-2 expression might be involved in malignant progression of endometrioid-type endometrial carcinoma. Site of Bcl-2 localization may be an important predictor of prognosis for patients with endometrioid-type endometrial carcinoma.

Adult↗

Apical vesicles bearing inositol 1,4,5-trisphosphate receptors in the Ca2+ initiation site of ductal epithelium of submandibular gland.

In polarized epithelial cells, agonists trigger Ca2+ waves and oscillations. These patterns may be caused by the compartmentalization of inositol 1,4,5-trisphosphate (IP3)-sensitive Ca2+ pools into specific regions. We have investigated the relationship between the distribution of IP3 receptors (IP3Rs) and the spatiotemporal pattern of Ca2+ signaling in the duct cells of the rat submandibular gland (SMG). Using immunofluorescence, although labeling was somewhat heterogeneous, the IP3Rs were colocalized to the apical pole of the duct cells. Immunoelectron microscopy identified small apical vesicles bearing IP3R2 in some types of duct cells. Real-time confocal imaging of intact ducts demonstrated that, after carbachol stimulation, an initial Ca2+ spike occurred in the apical region. Subsequently, repetitive Ca2+ spikes spread from the apical to the middle cytoplasm. These apical Ca2+ initiation sites were found only in some "pioneer cells," rather than in all duct cells. We performed both Ca2+ imaging and immunofluorescence on the same ducts and detected the strongest immunosignals of IP3R2 in the Ca2+ initiation sites of the pioneer cells. The subcellular localization and expression level of IP3Rs correlated strongly with the spatiotemporal nature of the intracellular Ca2+ signal and distinct Ca2+ responses among the rat SMG duct cells.

Animals↗

Age-related changes in the cerebrospinal fluid level of beta-endorphin and substance P. Short communication.

To evaluate the early age-related changes in neuropeptides, we have measured the cerebrospinal fluid (CSF) levels of beta-endorphin and substance P in young patients over a range of ages. Specimens of CSF were obtained from 39 neurologically normal children, aged 1 month to 10 years of age, and in 9 adult controls. CSF levels of both neuropeptides were observed to peak during the first year of life, and showed a negative correlation with increasing age. A significant positive correlation was observed between the CSF level of beta-endorphin and that of substance P.

Adult↗

Isolated trigeminal nerve metastases from breast cancer: an unusual cause of trigeminal mononeuropathy.

BACKGROUND: Mononeuropathy of a cranial nerve caused by brain metastases rarely occurs in patients with a malignant neoplasm. Even after the development of computed tomography (CT) and magnetic resonance imaging (MRI), few cases of brain metastases resulting in trigeminal mononeuropathy have been reported. We report a case of trigeminal mononeuropathy caused by a brain metastases that was detected on CT and MRI preoperatively, and was successfully treated by microsurgery and radiation. CASE DESCRIPTION: A 49-year-old woman with a history of breast cancer complained of right facial pain. CT and MRI revealed a brain tumor in the right Meckel's cave and cerebellopontine angle. She underwent surgery, and the diagnosis was metastatic breast cancer. No recurrence was detected on MRI performed 2 years after the resection and radiation of the tumor. CONCLUSIONS: Most of the reported cases of brain metastases causing a mononeuropathy occurred before the availability of CT; the mononeuropathy was diagnosed by neurologic or postmortem examination. Even after the development of CT and MRI, few cases of brain metastases resulting in trigeminal mononeuropathy have been reported. If such patients do not manifest symptoms of brain metastases other than the mononeuropathy, it is difficult to make the correct diagnosis without CT and MRI. Physicians must be aware of mononeuropathy as an uncommon presenting symptom of brain metastases.

Breast Neoplasms↗

Mutational analysis of the N-ras gene in acute lymphoblastic leukemia: a study of 125 Japanese pediatric cases.

A point mutation of the N-ras gene is one of the known genetic alterations identified in patients with acute lymphoblastic leukemia (ALL), but its clinical importance is still controversial. Using polymerase chain reactions, we examined codons 12, 13 and 61 of this gene in 125 Japanese childhood ALL patients (64 common-ALL, 22 pre-B-ALL, 33 T-ALL, 2 B-ALL, 3 undifferentiated ALL, and 1 unclassified ALL) including 9 relapsed patients. An N-ras point mutation was observed in 14 (11%) patients (9 common-ALL, 3 T-ALL, and 2 undifferentiated ALL; 13 patients at diagnosis and 1 at relapse). The patients with undifferentiated ALL harbored an N-ras mutation at a significantly higher rate. However, no correlation was found between the presence of an N-ras mutation and sex, age, or white blood count. There was no significant difference in the event-free survival rate between 13 fresh patients with an N-ras mutation and 103 patients with a wild-type configuration. The N-ras mutation was present in about 10% of childhood ALL cases but it did not have a prognostic impact. The sequence analyses revealed that the majority of the patients (13/14) had an N-ras mutation of a G to A transition. This finding was consistent with previous reports on N-ras mutations in acute leukemias in which the incidence of a G to A mutation was significantly higher in ALL than in myeloid malignancies.

Child↗

Caveolae: from a morphological point of view.

Caveolae in the plasma membrane have been a focus of intensive research during the past several years. There has been confusion concerning caveolae and caveola-like membrane domains, but it is now generally thought that the latter is a region distinct from caveolae. However, due to similar buoyancy of caveolae and caveola-like membranes, whether caveolae in situ are enriched with a given molecule is often difficult to be concluded by biochemical techniques alone. Furthermore, relatively shallow caveolae may be detected by some techniques, but not by others. Thus whether a molecule is enriched in caveolae should be confirmed by methods based on different principles. Among many putative caveolar molecules, those related to Ca2+ influx and extrusion were shown to be concentrated in caveolae by both immunocytochemical and biochemical techniques. In conjunction with other characteristics, the result implies that caveolae may function as a mobile compartment for Ca2+ signalling.

Animals↗

Esophageal strictures in children with recessive dystrophic epidermolysis bullosa: experience of balloon dilatation in nine cases.

BACKGROUND: Recessive dystrophic epidermolysis bullosa is a rare disorder characterized by extreme vulnerability of the squamous epithelium and mucous membranes. Minor trauma such as is caused by swallowing solid food is followed by blistering and scarring. Stricture formation at the pharyngoesophageal junction (C6 or C7) is the severest complication of this disease. METHODS: We evaluate the effectiveness of Microvasive Rigiflex balloon dilatation and extensive nutritional support as a primary treatment for this condition. Nine of 21 recessive dystrophic epidermolysis bullosa patients developed esophageal strictures at the level of the pharyngo-esophageal junction (C6). We treated them with intensive nutritional therapy followed by balloon dilatation, which produces longitudinal pressure and provides prompt relief from esophageal stricture. Eleven balloon dilatations have been performed in 9 patients. RESULTS: All patients had poor physical development and were severely malnourished; extensive nutritional support was required before treatment could begin. Balloon dilatation was performed once in seven patients and twice in two patients. No recurrent stricture formation was observed after balloon dilatation. CONCLUSION: Intensive nutritional support followed by balloon dilatation is the first choice of treatment for esophageal strictures complicating recessive epidermolysis bullosa. By following this regime, invasive surgery can be avoided.

Adolescent↗

Selective detection and differentiation of subgenus B adenoviruses (types 3, 7 and 11) by polymerase chain reaction.

Application of the polymerase chain reaction (PCR) method for detection of subgenus B adenoviruses (types 3, 7 and 11) was investigated. It is based on a simple (nonnested) PCR using primer pairs specific for the hexon-coding region. The PCR allowed amplification of DNA from subgenus B adenovirus prototype strains (types 3, 7 and 11) and adenovirus isolates (types 3 and 7), whereas it did not amplify DNA from subgenus A (type 31), C (types 1, 2, 5 and 6), D (types 8, 19 and 37), E (type 4) and adenovirus isolates (types 1, 2, 5 and 6). These results suggest that subgenus B adenoviruses (types 3, 7 and 11) are detectable selectively by means of PCR with primer pairs developed in this study. Amplified fragments from adenovirus types 3, 7 and 11 could be differentiated with restriction endonuclease analysis with Rsa I.

Adenoviridae↗

Coronary artery diameter and left ventricular function in patients on maintenance hemodialysis treatment: comparison between diabetic and nondiabetic patients.

BACKGROUND/AIMS: This study examined the role of diabetes mellitus on determining left ventricular function by evaluating coronary artery diameter in patients with end-stage renal disease on maintenance hemodialysis treatment. METHODS: We studied 12 diabetic and 12 nondiabetic patients on maintenance hemodialysis treatment without significant stenoses of the major epicardial coronary arteries. Patients were matched for age, sex distribution, duration of dialysis and incidence of major coronary risk factors. Left ventricular wall thickness (septal and posterior walls) and left ventricular diameter (end-diastolic and systolic phases), were measured by echocardiography. Hemodynamic measurements and coronary angiography were performed on the day of hemodialysis and coronary artery diameter at the proximal and mid portion of three major coronary arteries were measured using the computed densitometry method. RESULTS: Right and left anterior descending and circumflex coronary artery diameters were all significantly smaller and the frequency of coronary artery calcification was higher in diabetic (58%) compared to nondiabetic (8%) patients. Although there were no significant differences in left ventricular wall thickness, left ventricular diameter, mean right atrial pressure and cardiac index between the two groups, left ventricular end-diastolic pressure was significantly higher in diabetic (22 +/- 9 mm Hg) compared to nondiabetic patients (14 +/- 5 mm Hg). CONCLUSION: Despite that there were no significant stenoses of the major epicardial coronary arteries, diffuse luminal narrowing of the epicardial coronary arteries in diabetic patients on maintenance hemodialysis treatment was associated with increased left ventricular end-diastolic pressure.

Aged↗

Relationship between lupus nephritis activity and the serum level of soluble VCAM-1.

We measured the serum levels of soluble vascular cell adhesion molecule-1 (sVCAM-1), soluble E-selectin (sE-selectin) and soluble intercellular adhesion molecule-1 (sICAM-1) in 72 patients with systemic lupus erythematosus (SLE) (including patients with active nephritis) and 33 normal control subjects, to investigate the correlation between levels of adhesion molecules and disease and histological activity. Serum samples were obtained at the time of renal biopsy in 27 patients with lupus nephritis. The 27 patients were divided into groups according to the World Health Organization (WHO) class as follows: class I + II, n = 11; class III + IV, n = 13 and class V, n = 3. We also determined the activity index (AI) in these 27 renal biopsy specimens. We obtained serial measurements of the serum levels of soluble adhesion molecules in 11 patients to examine the difference between active and remission stages. The serum level of sVCAM-1, but not sE-selectin or sICAM-1, was correlated with parameters of SLE disease activity, including the SLE disease activity index score, the anti-double stranded DNA antibody titer, the C3 level, the C4 level and the CH50 level. The serum levels of sVCAM-1, sE-selectin and sICAM-1 were significantly higher in patients with SLE than in controls (P = 0.006, P = 0.0005 and P = 0.04, respectively). The serum level of sVCAM-1 was significantly higher in patients with active lupus nephritis (WHO classes III and IV) than in patients in inactive lupus nephritis (WHO classes I and II) (P = 0.0016). The sVCAM-1 level was significantly elevated in patients with an AI > or = 4 compared with patients with an AI < 4 (P = 0.0025). The sVCAM-1 level decreased significantly during remission (P = 0.0033). The serum level of sVCAM-1 was elevated in patients with active lupus nephritis (WHO classes III and IV) and in patients with high AI scores. The serum level of sVCAM-1 was correlated with the SLE disease activity and decreased during remission. Therefore, the sVCAM-1 level may be a useful marker of lupus nephritis activity.

Adolescent↗