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Biomedical subjects

E Ito

Publications and source records attributed to E Ito.

At least 73 records · Page 4Linked to original sources
PubMed2000

Multiple organ damage caused by a new toxin azaspiracid, isolated from mussels produced in Ireland.

A new type of food poisoning resulting from ingestion of mussels produced in Ireland occurred in the Netherlands in 1995 and then reoccurred in Ireland in 1997. As the causative agent, azaspiracid, was isolated in pure form and revealed to have a structure entirely unlike other known algal toxins, in vivo studies with mice were carried out to elucidate the pathological injuries caused by the toxin. By per os administration, the toxin caused necrosis in the lamina propria of the small intestine and in lymphoid tissues such as thymus, spleen and the Peyer's patches. Both T and B lymphocytes were injured. Additionally a fatty change was observed in the liver. These injuries distinctly differed from those caused by the representative diarrhetic shellfish toxin, okadaic acid.

Administration, Oral↗
PubMed2000

Temperature-dependent modulation of blood platelet movement and morphology on poly(N-isopropylacrylamide)-grafted surfaces.

Poly(N-isopropylacrylamide) (PIPAAm) exhibits a reversible, temperature-dependent soluble/insoluble transition at its lower critical solution temperature (LCST) of 32 degrees C in aqueous media. The temperature-responsive PIPAAm was grafted onto tissue culture polystyrene (TCPS) dish surfaces by electron beam irradiation. Blood platelet behaviors on PIPAAm-grafted surface were examined by computerized image analysis and scanning electron microscopy. Platelet behaviors on this surface were dramatically dependent upon temperature, but those on poly(ethylene glycol)(PEG)-grafted or polystyrene remained unchanged. Below the 32 degrees C (LCST), platelets on PIPAAm-grafted surfaces retained a rounded shape and an oscillating vibratory microbrownian motion for extended times, similarly to those on PEG-grafted surfaces. Above the LCST, platelets readily adhered, spread and developed characteristic pseudopodia on PIPAAm-grafted surface similarly to those on TCPS. An ATP synthesis inhibitor failed to hinder prevention of platelet adhesion onto PIPAAm-grafted surface (below the LCST) suggesting that the preventive mechanism is ATP-independent similarly to that of PEG-grafted surfaces. These results correlate platelet surface activation state with the hydration and structure of polymer surfaces, and demonstrate the ability to modulate such reactions by a small temperature change in situ.

Acrylamides↗
PubMed2000

Acquisition of neuronal proteins during differentiation of NG108-15 cells.

The differentiated type of neuroblastomaxglioma hybrid cell line, NG108-15, has widely been used in in vitro studies instead of primary-cultured neurons. Here we examined whether NG108-15 cells can be used as a model for studying the neuronal differentiation process. We compared the expression of neuronal proteins (neurofilament 200 (NF200), phosphorylated-NF200 (p-NF200), microtubule associated protein 2, synaptophysin, syntaxin 1, choline acetyltransferase, and acetylcholinesterase (AChE)) and a glial protein (vimentin) between undifferentiated and differentiated NG108-15 cells by immunocytochemistry and immunoblot analysis. The expression of all neuronal proteins, with the exception of NF200 and p-NF200, was positive in differentiated cells, but almost negative in undifferentiated cells. On the other hand, cytoskeletal intermediate filaments (NF200 and p-NF200) for neurons and that (vimentin) for glia were present in both undifferentiated and differentiated cells. Furthermore, a high expression of AChE mRNA was confirmed in differentiated cells by reverse transcription-PCR analysis. Our results showed that even though the expression of cytoskeletal filaments does not change during differentiation of NG108-15 cells, these cells during differentiation can serve as an appropriate tool for investigating and understanding the mechanisms involved in neuronal development and differentiation.

Acetylcholinesterase↗
PubMed2000

Neuronal components of the superior and inferior tentacles in the terrestrial slug, Limax marginatus.

To identify the types of neurons and to infer the patterns of connectivity in slug tentacles, we stained the neurons in the superior and inferior tentacles in the terrestrial slug, Limax marginatus, by backfilling of the tentacular nerves with Lucifer yellow. Four types of stained neurons, '(1) sensory neurons', '(2) gamma cells', '(3) ganglion cells', '(4) lateral cells', were identified both in the superior and inferior tentacles. Three subtypes of the sensory neurons, '(1a) round sensory neurons', '(1b) spindle-shaped sensory neurons', and '(1c) small sensory neurons', were found in the digits. The gamma cells and the ganglion cells were interneurons. Three subtypes of gamma cells, '(2a) round monopolar gamma cells', '(2b) round bipolar gamma cells', and '(2c) large gamma cells', were present in the digits. The ganglion cells were composed of '(3a) monopolar ganglion cells', '(3b) bipolar ganglion cells', and '(3c) elongated ganglion cells'. The monopolar and bipolar types were located both in the tentacular ganglia and digits, whereas the elongated type was present only in the tentacular ganglia. The lateral cells, whose function is unknown, were found in the dermo-muscular sheaths of the tentacles. Our study provides the first description of the neuronal map of inferior tentacles in gastropods. The results showed no differences in the morphological features of stained neurons between the superior and inferior tentacles in L. marginatus.

Animals↗
PubMed2000

Nitric oxide generation around buccal ganglia accompanying feeding behavior in the pond snail, Lymnaea stagnalis.

Although there are many lines of evidence for both the presence of nitric oxide synthase (NOS) in the central nervous system (CNS) and the effects of NO on activating and modulating the feeding circuit in Lymnaea stagnalis, there has been no direct evidence that NO generation in the CNS accompanies feeding behavior. In the present study, we used a NO specific electrode to measure the increase in NO concentration around the buccal ganglia when the lips of semi-intact preparations of L. stagnalis were stimulated by sucrose. The NO concentration of the buccal ganglia was significantly increased by an application of sucrose to the lips. A NO scavenger and a NOS inhibitor suppressed this increase in NO concentration. A pair of putative NO-generative neurons in the buccal ganglia, the B2 cells, are active during the inter-feeding phase, and the bursting of the B2 cell elicited by sucrose application starts simultaneously with the feeding response. The rhythmic pulses of NO generation corresponded well with the rhythmic bursting of the B2 cells, which itself corresponds to the 'fictive feeding response'. The present data provide the first direct evidence that NO is generated in the buccal ganglia of L. stagnalis and is involved in a specific behavior such as feeding.

Animals↗
PubMed2000

Functional characterization of the two alternative promoters of human p45 NF-E2 gene.

OBJECTIVE: The transcription factor NF-E2, a heterodimeric protein complex composed of p45 and small Maf family proteins, is considered crucial for the proper differentiation of erythrocytes and megakaryocytes in vivo. We report the results of studies aimed at understanding the regulatory mechanisms controlling p45 gene expression in erythroid cells. MATERIALS AND METHODS: Human p45 mRNAs have two alternative isoforms, aNF-E2 and fNF-E2, and these isoforms are transcribed from the alternative promoters. We investigated lineage-specific expression of both isomers in human erythroid and megakaryocytic cells by reverse transcriptase polymerase chain reaction or Northern blot analysis. For functional characterization of both promoters, plasmids in which reporter genes were placed under the control of a series of truncated or mutated promoter fragments were transfected to human hematopoietic cell lines. RESULTS: When CD34(+) cells isolated from human cord blood were induced to unilineage erythroid or megakaryocytic differentiation in liquid suspension culture, both transcripts, although barely detected at day 0, were induced in both erythroid and megakaryocytic cultures. fNF-E2 mRNA was found to be more abundant in erythroid cells than megakaryocytic cells at day 7 of culture. Although both isomers were expressed in human erythroid-megakaryocytic cell lines, megakaryocytic maturation with loss of erythroid phenotype induced by phorbol 12-myristate 13-acetate (PMA) resulted in exclusive downregulation of fNF-E2, suggesting that fNF-E2 promoter is more erythroid specific. Functional analysis of fNF-E2 promoter showed that the promoter is active only in erythroid-megakaryocytic cells and that the double GATA site in the proximal region is necessary for its efficient activity. CONCLUSION: These results suggest that GATA proteins, which govern the differentiation of erythroid lineage cells, are required for full promoter activity of the p45 gene.

Binding Sites↗
PubMed2000

Elasticity mapping of living fibroblasts by AFM and immunofluorescence observation of the cytoskeleton.

Using the force mapping mode of atomic force microscopy (AFM), we measured spatial distribution of elastic moduli of living mouse fibroblasts (NIH3T3) in a physiological condition. The nuclear portion of the cellular surface is about 10 times softer than the surroundings. Stiffer fibers are confirmed in the elastic images. In order to investigate origin of the softer nuclear portion and the stiffer fibers, we fixed the identical cells imaged by the AFM, and carried out immunofluorescence observation for three types of cytoskeletal filaments--actin filaments, microtubules, and intermediate filaments, using confocal laser scanning microscopy (CLSM). A comparison between the AFM and the CLSM images revealed that the elasticity of the cells was concerned not only with the distribution of actin network, but also with intermediate filaments, whereas microtubules had no large effect on the measured elasticity.

3T3 Cells↗
PubMed2000

Three-dimensional characterization of interior structures of exocytotic apertures of nerve cells using atomic force microscopy.

We examined the interior structure of exocytotic apertures in synaptic vesicles of neuroblastoma x glioma hybrid cells using atomic force microscopy. The atomic force microscopy detected apertures of 50-100nm in diameter at various depths within the varicosities of these cells. We were also able to image a regular radial pattern on the wall and lump-like structures at the bottom of these apertures. In contrast, scanning electron microscopy could only detect the apertures but not the fine details of their interior. The cells examined here exhibited the same electrophysiological properties and expression of synaptophysin and syntaxin 1 as presynaptic terminals, as studied by various electrophysiological and imaging techniques. Our results indicate that atomic force microscopy allows three-dimensional viewing of the fine structures located inside exocytotic apertures in nerve cells.

Calcium↗
PubMed2000

Neuron-independent Ca(2+) signaling in glial cells of snail's brain.

To directly monitor the glial activity in the CNS of the pond snail, Lymnaea stagnalis, we optically measured the electrical responses in the cerebral ganglion and median lip nerve to electrical stimulation of the distal end of the median lip nerve. Using a voltage-sensitive dye, RH155, we detected a composite depolarizing response in the cerebral ganglion, which consisted of a fast transient depolarizing response corresponding to a compound action potential and a slow depolarizing response. The slow depolarizing response was observed more clearly in an isolated median lip nerve and also detected by extracellular recording. In the median lip nerve preparation, the slow depolarizing response was suppressed by an L-type Ca(2+) channel blocker, nifedipine, and was resistant to tetrodotoxin and Na(+)-free conditions. Together with the fact that a delay from the compound action potential to the slow depolarizing response was not constant, these results suggested that the slow depolarizing response was not a postsynaptic response. Because the signals of the action potentials appeared on the saturated slow depolarizing responses during repetitive stimulation, the slow depolarizing response was suggested to originate from glial cells. The contribution of the L-type Ca(2+) current to the slow depolarizing response was confirmed by optical recording in the presence of Ba(2+) and also supported by intracellular Ca(2+) measurement. Our results suggested that electrical stimulation directly triggers glial Ca(2+) entry through L-type Ca(2+) channels, providing evidence for the generation of glial depolarization independent of neuronal activity in invertebrates.

Animals↗
PubMed2000

Prolonged recovery of cardiac output after maximal exercise in patients with chronic heart failure.

OBJECTIVES: The aim of this study was to characterize the kinetics of cardiac output during recovery from maximal exercise in patients with chronic heart failure (CHF). BACKGROUND: Recent studies have shown that oxygen uptake kinetics during recovery from exercise are delayed in patients with CHF. However, the kinetics of cardiac output during recovery from maximal exercise in CHF has not been examined. METHODS: Thirty patients with CHF performed maximal upright ergometer exercise with respiratory gas analysis. Kinetics of oxygen uptake (VO2) and carbon dioxide output (VCO2) during recovery were characterized by T1/2, the time to reach 50% of the peak values. Cardiac output was measured at 1-min intervals during exercise and recovery. Kinetics of cardiac output during recovery were characterized by the ratios of cardiac output during the first 4 min of recovery to cardiac output at peak exercise. Overshoot of cardiac output was defined as a further increase in cardiac output at 1 min of recovery above the cardiac output at peak exercise. RESULTS: Both T1/2 VO2 and T1/2 VCO2 increased as CHF worsened. The ratios of cardiac output during recovery to cardiac output at peak exercise were significantly correlated with T1/2 VO2 (r = 0.47 to 0.62, p < 0.05) and T1/2 VCO2 (r = 0.40 to 0.70, p < 0.05). There was a negative correlation between cardiac index at peak exercise and both T1/2 VO2 (r = -0.65, p < 0.001) and T1/2 VCO2 (r = -0.60, p < 0.001). Overshoot of cardiac output was recognized in 11 of 30 patients. Cardiac index at peak exercise was significantly lower in patients with overshoot (4.5 +/- 0.9 L/min/m2) than in those without overshoot (6.1 +/- 2.1 L/min/m2, p < 0.05). However, because of a continued increase in cardiac output at 1 min of recovery in patients with overshoot, there were no differences in cardiac index after the first minute of recovery. Heart rate at peak exercise and recovery of heart rate did not differ between these groups. Overshoot of cardiac output was caused by a rebound increase in stroke volume which was due to a reduction in systemic vascular resistance. CONCLUSIONS: Prolonged kinetics of VO2 or VCO2 during recovery from maximal exercise represent impairment of circulatory response to exercise and delayed recovery of cardiac output after exercise. Overshoot of cardiac output at 1 min of recovery was characteristic of severe CHF with poor cardiac output response to exercise.

Analysis of Variance↗
PubMed2000

Low serum lipids suggest severe bone marrow failure in children with aplastic anemia.

BACKGROUND: Significantly low serum lipid levels are occasionally seen at the time of diagnosis in children with aplastic anemia (AA). The aim of the present study was to clarify the pathologic and clinical significance of pretreatment serum lipid levels in AA. METHODS: A questionnaire seeking precise data about AA in pediatric patients, including the initial laboratory data at the time of onset of AA and the clinical course of these patients, was sent to 18 institutes in Japan; 13 institutes responded to the questionnaire. In this retrospective study, data concerning hematologic examination and serum lipids were available for analysis in 127 children with AA. Serum lipoprotein patterns were analyzed using conventional agarose electrophoresis in eight patients. In order to elucidate the cause of hypolipidemia in AA, we assayed serum macrophage colony stimulating factor (M-CSF), which is well known to have apparent cholesterol-lowering activity, by using an enzyme-linked immunosorbent assay in seven patients with hypocholesterolemia and compared the results with those obtained in patients with iron-deficiency anemia (IDA). RESULTS: We found that pretreatment total cholesterol (TC) and triglyceride levels in the serum correlated well with counts of both nucleated cells and hemopoietic cells in the bone marrow (BM) and were inversely correlated with the lymphocyte ratio in both the BM and peripheral blood. Patients with serum TC lower than 150 mg/dL showed a poor response to any form of therapy except BM transplantation. There was no difference in the serum lipoprotein patterns between the controls and patients examined. The serum M-CSF level was significantly higher in patients with TC levels lower than 150 mg/dL compared with controls. CONCLUSIONS: These results indicate that the pretreatment serum lipid level may reflect hematopoietic activity within the BM and can help to predict the therapeutic response of each case of AA to treatment with immunosuppressive drugs, corticosteroids and anabolic steroids. These results also indicate that M-CSF may be one of the contributing causes of the hypocholesterolemia that occurs in both AA and IDA.

Adolescent↗
PubMed2000

Effect of cytokines on antifungal activity of human polymorphonuclear leucocytes against yeast cells of Paracoccidioides brasiliensis.

In our previous study, it was observed that human peripheral blood polymorphonuclear leucocytes (PMNs) exhibited a fungistatic effect on yeast cells of Paracoccidioides brasiliensis, and that interferon-gamma (IFN-gamma), but not tumor necrosis factor-alpha or interleukin-8 (IL-8), enhanced the antifungal activity of PMNs. In the present study, granulocyte-macrophage colony-stimulating factor (GM-CSF) also enhanced the PMN activity. GM-CSF-activated PMNs exhibited a killing effect on P. brasiliensis isolate Bt-4 and an enhanced fungistatic effect on isolate Aoki. IL-1beta activated PMNs to kill isolate Bt-4. Granulocyte colony-stimulating factor had no effect. Combinations of IFN-gamma with GM-CSF or IL-1beta, but not a combination of GM-CSF and IL-1beta, exhibited a synergistic effect in enhancing the antifungal activity of PMNs. These results strongly suggest that PMNs activated with IFN-gamma, GM-CSF and/or IL-1beta might play an important role in host defense in early infection with P. brasiliensis due to their enhanced antifungal activity.

Colony Count, Microbial↗
PubMed2000

Quantitative analyses of topography and elasticity of living and fixed astrocytes.

The topography and elasticity of living and fixed astrocytes cultured from the rat cerebra were studied quantitatively by atomic force microscopy (AFM). Ridge-like structures reflecting F-actin beneath the cell membrane were prominent in the contact-mode images of living astrocytes. Many of these ridges became unclear after fixation (2% glutaraldehyde). In addition, the ridge-like structures were invisible in the topography of living cells observed at zero-loading force in the force mapping mode, which is considered to show the real cell surface not pressed down by an AFM tip. The topography of fixed cells observed both in the contact mode and at zero-loading force in the force mapping mode was similar to that of living cells observed at zero-loading force in the force mapping mode, although some deformed areas were detected in the fixed cells. The elasticity map images of living astrocytes showed that the cell membrane above the nucleus was softer (2-3 kPa) than the surroundings, and that the cell membrane above F-actin was stiffer (10-20 kPa) than the surroundings. In the elasticity map images of fixed astrocytes, on the other hand, the elasticity of the cells was found to be relatively uniform (200-700 kPa) irrespective of the inner structures of cells. These results show that images observed by AFM should be carefully examined in consideration of the force introduced to specimens and the elasticity of specimens to find out the real surface topography.

Actins↗
PubMed2000

Time-lapse viscoelastic imaging of living fibroblasts using force modulation mode in AFM.

Using the force modulation mode in atomic force microscopy, we have succeeded in capturing time-lapse viscoelastic images of living mouse fibroblasts (NIH3T3) for several hours in a physiological condition without damaging the fibroblasts. Elongation of the lamellipodia and swelling of blebs were observed in time-lapse topographic images, which were taken every 10 min. The corresponding viscoelastic responses at a frequency of 600 Hz were visualized as consecutive images. The stiffer part of the cell body was fairly stable and did not show morphological changes for over 1 h. This is probably due to excess condensation of the actin network, hardening the cell cortex, and lowering the cytoskeletal activity. The nuclear portion of the cell body seems to be slightly less viscous than the peripheral region.

3T3 Cells↗
PubMed2000

A case of stage-IVb cervical adenocarcinoma successfully treated by combination chemotherapy: case report.

A 54-year-old patient with a Stage IVb adenocarcinoma of the cervix was treated with combination chemotherapy. This regimen consisted of intravenous cisplatin (70 mg/m2) and aclacinomycin A (30 mg/m2) on Day 1, followed by mitomycin C (5 mg/m2) on Day 2 and 3. A pathologically complete response was achieved by this regimen. The patient is well and has been free of symptoms for 66 months.

Adenocarcinoma↗
PubMed2000

Surgical management of genital prolapse: is chain cystourethrography useful for evaluating anatomical corrections and urinary symptoms after surgery?

OBJECTIVE: To evaluate the relationship between chain cystourethrography and surgery for genital prolapse and urinary symptoms. METHODS: A retrospective study of women with genital prolapse was conducted from January 1991 through December 1997. To assess the preoperative and postoperative anatomical situations objectively, chain cystourethrography was performed. RESULTS: Fifty-seven patients underwent surgical repairs for genital prolapse. All of them recovered from the genital prolapse both subjectively and objectively after surgery. Chain cystourethrography is useful for evaluating postoperative anatomical corrections. However, 6 patients (12%) suffered from a recurrent feeling of genital prolapse, and 14 patients (28%) had urinary symptoms postoperatively. CONCLUSIONS: Our treatment showed good anatomical corrections based on chain cystourethrography, and there were no prognostic differences among the surgical procedures. However, anatomical correction does not always mean improvement of urinary symptoms. Further studies are needed to clarify what factors contribute to the prognosis in such cases.

Adult↗
PubMed2000

Expression of transcription factors during megakaryocytic differentiation of CD34+ cells from human cord blood induced by thrombopoietin.

Although normal megakaryocytic development has been shown to require the presence of functional GATA-1 and NF-E2 transcription factors in vivo, the roles of other members of the GATA binding factors and NF-E2 family during megakaryocytic differentiation are unclear. the present study, the expression of GATA family members, GATA-1 and GATA-2, a GATA-binding factor, EVI-1, the large subunit of NF-E2 factor, p45 and the related factors, Nrf1, Nrf2, Nrf3, BACH1, BACH2, and the small subunit of NF-E2, MAFK and MAFG has been examined in human megakaryocytic and erythroid cells by reverse transcriptase-polymerase chain reaction. CD34+ cells isolated from human cord blood were induced to unilineage megakaryocytic or erythroid differentiation in liquid suspension culture in the presense of thrombopoietin or erythropoietin, respectively. Each lineage was identified by monoclonal antibody against GPIIb/IIIa or glycophorin A. In megakaryocytic culture, p45, Nrf1, Nrf2, BACH1, MAFK and MAFG mRNAs were induced similarly to erythroid culture. Nrf3 mRNA was barely detected in both cultures. BACH2 was induced only in megakaryocytic culture, although the level of expression was low. Furthermore, the profiles of transcription factors involved in hematopoiesis, EVI-1 and Ets-1 mRNAs were induced only in megakaryocytic culture. Megakaryocytic and erythroid differentiation pathways are closely related to each other, and these two lineage cells share a number of lineage-specific transcription factors. However, the results showed that the profile of the expression of these transcription factors in megakaryocytic cells is distinct from that of erythroid lineage. The dynamic changes in the levels of different transcription factors that occur during primary megakaryocytic differentiation suggest that the levels of these factors may influence the progression to specific hematopoietic pathways.

Antigens, CD34↗