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Biomedical subjects

M Yamaguchi

Publications and source records attributed to M Yamaguchi.

At least 37 records · Page 2Linked to original sources
PubMed2005

A rare case of the cutaneous form of adult T-cell leukaemia/lymphoma: assessment of remission by PCR for clonal T-cell receptor gamma gene rearrangements in an electron beam-irradiated cutaneous lesion.

Adult T-cell leukaemia/lymphoma is a lymphoproliferative disorder aetiologically associated with human T-cell lymphotropic virus type I infection. A cutaneous lesion often develops in the disease, and in rare cases, is even the only manifestation. Here we report a rare case of 'cutaneous' adult T-cell leukaemia/lymphoma with neither atypical cells in the peripheral blood nor lymph node involvement. All nodular lesions were completely eliminated after local electron beam irradiation (20 Gy/nodule in total). To evaluate whether or not there were residual lymphoma cells in the skin, we performed PCR to detect clonal T cell receptor gamma gene rearrangements. The sample from the nodule before irradiation showed evidence of a rearranged band, which was not detected at the same site after treatment nor in any peripheral blood. The findings suggest that this procedure is useful for the evaluation of therapeutic effects and the early detection of lymphoma recurrence.

Female↗
PubMed2005

Multi-aspect gene relation analysis.

Recent progress in high-throughput screening technologies has led to the production of massive amounts data that we can use to understand biological systems. To interpret this data, biologists often need to analyze the characteristics of a set of genes by using Gene Ontology (GO) annotation. We are proposing a novel method for assisting such an analysis. Given a set of genes, the method automatically extracts several analyzing aspects in terms of a subset of genes that are attached to some related GO terms. It then creates a gene-attribute bipartite graph that highlights the aspect selected by the user according to his/her interests. We describe this method in detail and report on an experiment where the proposed method is applied to the analysis of rat kidney expression data.

Animals↗
PubMed2005

Thiazolidinedione (pioglitazone) blocks P. gingivalis- and F. nucleatum, but not E. coli, lipopolysaccharide (LPS)-induced interleukin-6 (IL-6) production in adipocytes.

An elevated level of C-reactive protein (CRP) predicts the future development of coronary heart disease. Periodontitis appears to up-regulate CRP. CRP is produced by hepatocytes in response to interleukin-6 (IL-6). A major source of IL-6 in obese subjects is adipocytes. We hypothesized that lipopolysaccharide (LPS) from periodontal pathogens stimulated adipocytes to produce IL-6, and that the production was suppressed by the drugs targeted against insulin resistance, thiazolidinedione (pioglitazone), since this agent potentially showed an anti-inflammatory effect. Mouse 3T3-L1 adipocytes were stimulated with E. coli, P. gingivalis, and F. nucleatum LPS. The IL-6 concentration in culture supernatants was measured. All LPS stimulated adipocytes to produce IL-6. Although pioglitazone changed adipocyte appearance from large to small, and completely suppressed P. gingivalis and F. nucleatum LPS-induced IL-6 production, E. coli LPS-induced IL-6 production was not efficiently blocked. Thus, pioglitazone completely blocked periodontal-bacteria-derived LPS-induced IL-6 production in adipocytes, a major inducer of CRP.

3T3 Cells↗
PubMed2005

Age-related changes in haematology and serum chemistry of Weiser-Maples guineapigs (Cavia porcellus).

Age-related changes in haematology and serum chemistry values were examined in male and female Weiser-Maples guineapigs (Cavia porcellus). Haematological changes that significantly (P<0.01) correlated with ageing were increased white blood cell and neutrophil counts in both sexes, decreased lymphocyte counts in both sexes, decreased reticulocyte and platelet counts in males, and decreased basophil counts in females. For serum chemistry, increases in total protein, triglycerides, blood urea nitrogen and creatinine were seen in both sexes, along with increases in total cholesterol in males and sodium in females. Decreased alkaline phosphatase in both sexes and decreased chloride in males were significantly (P<0.01) associated with age. These age-related changes are compared with the published literature.

Age Factors↗
PubMed2005

Hypercoagulant states in malignant lymphoma.

The incidence of severe complications, such as disseminated intravascular coagulation (DIC) in malignant lymphoma, differs between clinical stages and histological types of the disease, but they occur frequently in stage IV or natural killer (NK) cell lymphoma. Patients with stage IV or NK cell lymphoma exhibit abnormal thrombotic and hemostatic states. One of the mechanisms in DIC might involve elevated cytokine expression by lymphoma cells stimulating the expression of tissue factor (TF) in blood cells or surrounding tissue. During chemotherapy for lymphoma, the white blood cell count was significantly reduced at days 1 and 3, but significantly increased at days 7 and 9. At day 7 of chemotherapy, leukocyte TF mRNA levels were significantly increased. Plasma concentrations of granulocyte elastase derived-XDP (GEXDP) levels correlated with D-dimer levels, suggesting that almost all elevated D-dimer is GE-XDP. C-reactive protein (CRP), GE-XDP and D-dimer were significantly elevated in patients with infection, DIC or acute respiratory distress syndrome (ARDS). Analysis of patients with DIC or ARDS revealed that TF mRNA correlated with D-dimer, and GE-XDP correlated with leukocyte count, CRP and D-dimer, suggesting that inflammatory changes due to thrombosis may cause the activation of leukocytes during chemotherapy.

C-Reactive Protein↗
PubMed2004

MEG measurement of event-related brain activity evoked by emotional prosody recognition.

Cortical areas involved in processing of emotional prosody (EP) in spoken language, such as joy or sadness, have been found in functional magnetic resonance imaging (fMRI) studies bilaterally or dominantly in the right frontal or temporal lobes. In this study, we investigated spatiotemporal patterns of cortical activity related to EP processing using magnetoencephalography (MEG). In this experiment, a joyful face (JF) or a sad face (SF) was displayed after voices which had emotional features of joy (joy prosody: JP) or sadness (sad prosody: SP) were presented. Subjects were requested to judge whether emotional features of the voice and the face were identical or not. MEG signals evoked by emotional voices were measured and significant differences of cortical activities associated with processing of emotional feature were observed between the right and left hemisphere during the latency of 100-150 ms that includes the N1m component. Our study suggests that MEG is a useful method, in addition to fMRI and event-related scalp potentials (ERP) for studying non-invasively EP processing in the human brain.

Acoustic Stimulation↗
PubMed2004

Effect of word familiarity on visually evoked magnetic fields.

This study investigated the effect of word familiarity of visual stimuli on the word recognizing function of the human brain. Word familiarity is an index of the relative ease of word perception, and is characterized by facilitation and accuracy on word recognition. We studied the effect of word familiarity, using "Hiragana" (phonetic characters in Japanese orthography) characters as visual stimuli, on the elicitation of visually evoked magnetic fields with a word-naming task. The words were selected from a database of lexical properties of Japanese. The four "Hiragana" characters used were grouped and presented in 4 classes of degree of familiarity. The three components were observed in averaged waveforms of the root mean square (RMS) value on latencies at about 100 ms, 150 ms and 220 ms. The RMS value of the 220 ms component showed a significant positive correlation (F=(3/36); 5.501; p=0.035) with the value of familiarity. ECDs of the 220 ms component were observed in the intraparietal sulcus (IPS). Increments in the RMS value of the 220 ms component, which might reflect ideographical word recognition, retrieving "as a whole" were enhanced with increments of the value of familiarity. The interaction of characters, which increased with the value of familiarity, might function "as a large symbol"; and enhance a "pop-out" function with an escaping character inhibiting other characters and enhancing the segmentation of the character (as a figure) from the ground.

Adult↗
PubMed2004

Role of zinc in regulation of protein tyrosine phosphatase activity in osteoblastic MC3T3-E1 cells: zinc modulation of insulin-like growth factor-I's effect.

Zinc, an essential trace element, has been demonstrated to stimulate bone growth in animal and human. The cellular mechanism by which zinc stimulates bone growth has not been fully clarified. The effect of hormone and zinc on protein tyrosine phosphatase activity in osteoblastic MC3T3-E1 cells was investigated. Cells were cultured for 72 h in medium containing 10% fetal bovine serum (FBS) to obtain subconfluent monolayers, and then exchanged to culture medium containing either vehicle, zinc sulfate or various hormones in the absence of 10% FBS. After medium change, cells were cultured for 48 h. Protein tyrosine phosphatase activity in the lysate of cells was significantly increased by culture with zinc (10(-6) - 10(-4) M). The effect of zinc in increasing the enzyme activity was completely blocked by culture with cycloheximide (10(-7 )M), an inhibitor of protein synthesis, or 5, 6-dichloro-l-beta-D- riboifuranosylbenzimidarzole (DRB) (10(-6) M), an inhibitor of translational activity. Addition of calcium chloride (10 microM) into the reaction mixture caused a significant increase in protein tyrosine phosphatase activity; this increase was completely blocked in the presence of trifluoperazine (50 microM), an antagonist of calmodulin. Culture with zinc caused a significant increase in Ca2+/calmodulin-dependent protein tyrosine phosphatase activity in osteoblastic cells. Protein tyrosine phosphatase activity was significantly raised by culture with parathyroid hormone (human PTH [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33]; 10(-7) M), 17beta-estradiol (10(-7) M), insulin-like growth factor-I (IGF-I; 10(-8) M) or insulin (10(-8) M). The enzyme activity was not significantly enhanced by the addition of calcium (10 microM) into the reaction mixture. The effect of PTH or IGF-I in increasing protein tyrosine phosphatase activity was completely blocked by culture with DRB. The IGF-I-induced increase in enzyme activity was significantly enhanced by culture with zinc. Such an effect was not seen in the case of PTH. Moreover, the effect of IGF-I in increasing proliferation of osteoblastic cells was significantly enhanced by culture with zinc. The effect of PTH was not enhanced by zinc. This study demonstrates that protein tyrosine phosphatase activity in osteoblastic cells is enhanced by various bone anabolic factors, and that zinc modulates the effect of IGF-I on protein tyrosine phosphatase activity and cell proliferation.

3T3 Cells↗
PubMed2004

Neurovascular protection reduces early brain injury after subarachnoid hemorrhage.

BACKGROUND AND PURPOSE: Cell death, especially apoptosis, occurred in brain tissues after subarachnoid hemorrhage (SAH). We examined the relationships between apoptosis and the disruption of blood-brain barrier (BBB), brain edema, and mortality in an established endovascular perforation model in male Sprague-Dawley rats. METHODS: A pan-caspase inhibitor (z-VAD-FMK) was administered intraperitoneally at 1 hour before and 6 hours after SAH. Expression of caspase-3 and positive TUNEL was examined as markers for apoptosis. RESULTS: Apoptosis occurred mostly in cerebral endothelial cells, partially in neurons in the hippocampus, and to a lesser degree in the cerebral cortex. Accordingly, increased BBB permeability and brain water content were observed, accompanied by neurological deficit and a high mortality at 24 hours after SAH. z-VAD-FMK suppressed TUNEL and caspase-3 staining in endothelial cells, decreased caspase-3 activation, reduced BBB permeability, relieved vasospasm, abolished brain edema, and improved neurological outcome. CONCLUSIONS: The major effect of z-VAD-FMK on early brain injury after SAH was probably neurovascular protection of cerebral endothelial cells, which results in less damage on BBB.

Amino Acid Chloromethyl Ketones↗
PubMed2004

Neuropeptides stimulate production of interleukin-1 beta, interleukin-6, and tumor necrosis factor-alpha in human dental pulp cells.

OBJECTIVE: Orthodontic tooth movement causes inflammatory reactions in the periodontal membrane and dental pulp. It has been reported that substance P (SP) and calcitonin gene-related peptide (CGRP), both sensory neuropeptides, are manifested in the dental pulp of rats during experimental tooth movement, suggesting that they might be involved in the dental pulp inflammation during orthodontic tooth movement. However, the relationships between neuropeptides and pro-inflammatory cytokines have not been fully elucidated. MATERIALS AND METHODS: Human dental pulp (HDP) fibroblasts were prepared from 6 healthy young volunteers (3 males, 3 females; 15-25 years old) during the course of orthodontic treatment. HDP cells were incubated for 24 h in fresh medium containing 2% FCS in the presence of various concentrations of CGRP (10(-12) to 10(-4) M) and SP (10(-12) to 10(-4) M), and the levels of interleukin (IL)-1 beta, IL-6, and tumor necrosis factor (TNF)-alpha present in the media were determined using commercially available high-sensitivity enzyme-linked immunosorbent assay kit. RESULTS: We examined the effects of stimulation by these neuropeptides on the production of inflammatory cytokines in HDP fibroblasts, and found that the levels of IL-1 beta, IL-6, and TNF-alpha increased in a time- and concentration-dependent manner. However, the neuropeptides did not act synergistically to increase cytokine secretion in HDP cells or significantly modify LPS-induced cytokine production by HDP cells. CONCLUSIONS: Our results suggest that human pulp fibroblasts may be involved in the progress of inflammation in pulp tissue during orthodontic tooth movement, as they produced large amounts of IL-1 beta, IL-6, and TNF-alpha following stimulation with neuropeptides.

Calcitonin Gene-Related Peptide↗
PubMed2004

Development and evaluation of a new gray-scale test pattern to adjust gradients of thoracic CT imaging.

The purpose of the present study was to evaluate the usefulness of a new gray-scale test pattern (NGTP) that was developed to easily adjust the gradients of thoracic CT imaging and enable visual consistency. The Society of Motion Picture and Television Engineers (SMPTE) pattern and the NGTP were used for comparison. The luminance character of two test patterns was evaluated by a luminance meter with three different window widths and levels (for default, mediastinum and lung). We also investigated whether SMPTE or NGTP is more suitable for adjusting the gradient of thoracic CT imaging. We found that it was easier to adjust the gradient of thoracic CT imaging with NGTP than with SMPTE, because the digital range of NGTP is 12 bits (the value of 4,096 HU, from -1,024 to 3,071 HU), and adjustable in any window width. We were able to adjust the gradients of hard-copy and soft-copy thoracic CT imaging within several hours using NGTP. We propose that NGTP is the most suitable tool for adjusting the gradients of thoracic CT imaging. NGTP can cope with any medical diagnostic display system connected with CT or MRI equipment in a network because it is in DICOM format.

Quality Control↗
PubMed2004

Non-invasive monitoring of gingival crevicular fluid for estimation of blood glucose level.

Development of a non-invasive method for measuring the blood glucose level is an urgent necessity, and putting such a method into practical use will enable some of the physical and mental stress that patients with diabetes have to endure to be removed. To realise a non-invasive blood glucose monitor, the gingival crevicular fluid (GCF) was measured. A GCF-collecting device was developed that was designed to be disposable, biocompatible and small enough to be inserted in the gingival crevice for collection of a sub-microlitre sample of GCF. Also, a high-sensitivity glucose testing tape incorporated in the device was developed. Red laser light in a portable optical device measured the colour density of the testing tape. Standard glucose solutions were used to investigate the measurement accuracy of the GCF glucose monitor and showed a correlation coefficient of R = 0.99 (n = 20) between the optical density and the glucose levels. The GCF glucose monitor was evaluated on healthy Swedish and Japanese adults (n = 10) and both GCF glucose levels (GCFLs) and blood glucose levels (BGLs) were measured in conjunction with meal loads. The GCFLs were about 1/10-1/560 lower than the BGLs. No difference in the range of GCFLs between the Swedish and the Japanese subjects was observed. Therefore it was concluded that physique, body mass index and life-style, such as dietary habit, did not significantly influence the GCFLs. Further, the correlation coefficients of all the subjects were 0.70 and 0.88 with each group. It was suggested that GCF could be used as a method of non-invasive blood glucose measurement.

Adult↗
PubMed2004

Stability of 11C-labeled PET radiopharmaceuticals.

The stability of widely used 11C-radiopharmaceuticals was investigated. The purity of many 11C-radiopharmaceuticals was found to be low even at the end of synthesis and to lower with time by radiolysis. Examinations of the effects of radical scavengers showed that the radiopharmaceuticals were classified into four groups: Group 1 showing excellent stability; Group 2 showing suppressed radiolysis in the presence of a selective scavenger of hydroxyl radicals; Group 3 showing suppression in the presence of a selective scavenger of hydrated electrons; Group 4 showing suppression in the presence of both scavengers. Using appropriate additives according to these classes, 11C-radiopharmaceuticals were prepared with excellent radiochemical purity even with high levels of radioactivity and specific activity.

Carbon Radioisotopes↗
PubMed2004

Significance of administration of fat emulsion: hepatic changes in infant rats receiving total parenteral nutrition with and without fat.

Total parenteral nutrition (TPN) is associated with cholestasis and hepatic steatosis, which can be lethal in infants who cannot be fed orally. The present animal study focused on the metabolic complications in the liver that may occur due to the excessive administration of fat-free TPN. Thirty infant (3-week-old) male SD rats weighing 60-70 g were randomly allocated to five groups (n = 6): the OD group received an oral diet, the FT group received an oral diet and was fasted overnight on the last day of experiment before sacrifice, the 0% fat group received TPN without fat, the 20% fat group received TPN with 20% of calories from fat emulsion, and the 40% fat group received TPN with 40% of calories from fat emulsion. All TPN regimens were isocaloric, isonitrogenic, and administered for 4 days. In the 0% fat group, plasma levels of liver enzymes were significantly higher than in the other groups. Pathological examination showed hepatomegaly and severe fatty changes without cholestasis in the 0% fat group. The results of this study in infant rats indicate the importance of including fat in the TPN regimen in order to prevent the abnormal hepatic changes associated with the excessive administration of fat-free TPN.

Alanine Transaminase↗