Search PubMed⌕ Search

Biomedical subjects

M Fukuda

Publications and source records attributed to M Fukuda.

At least 433 records · Page 24Linked to original sources
PubMed1998

The role of mucosal mast cell degranulation and free-radical generation in intestinal ischaemia-reperfusion injury in rats.

OBJECTIVES: In this study, we determined the role of mucosal mast cell (MMC) activation in the pathogenesis of intestinal ischaemia-reperfusion (I/R) injury by immunohistochemical analysis using anti-RMCP II antibody. In addition, we investigated the role of free-radical generation in the activation of MMCs in this model. METHODS: In the first experiment, rats were divided into four groups: (1) sham operated; (2) I/R + saline; (3) I/R + the mast cell stabilizer, MAR-99 (30 mg/kg); and (4) I/R + MAR-99 (100 mg/kg). Treatment with MAR-99 was started 1 h before the occlusion of the superior mesenteric artery (SMA). In the second experiment, rats were divided into five groups: (1) sham operated; (2) I/R + saline; (3) I/R + superoxide dismutase (SOD; 50,000 U/ml); (4) I/R + catalase (90,000 U/ml); and (5) I/R + allopurinol (50 mg/kg/day). Intravenous administration of SOD and catalase was performed 1 h before SMA occlusion. Oral administration of allopurinol was started 2 days before I/R surgery. We measured several parameters of intestinal mucosal injury and evaluated the degranulation of MMCs by using an immunohistochemical technique. RESULTS: The number of resting MMCs, detected by anti-RMCP II antibody, was significantly decreased in the I/R-treated rats. The I/R treatment induced a decrease in the mucosal histamine content and an increase in plasma histamine levels. Mucosal permeability in the small intestine was significantly enhanced by I/R treatment. However, these changes were significantly prevented by pretreatment with the MMC stabilizer, MAR-99. Furthermore, administration of several free-radicals scavengers (SOD, catalase, and allopurinol) also blocked the I/R-induced degranulation of MMCs. CONCLUSION: These data indicate that activation of MMCs was involved in the pathogenesis of I/R-induced intestinal mucosal injury. In addition, some parts of the I/R-induced MMC activation pathway were mediated by free-radical generation.

Animals↗
PubMed1998

Fecal excretion of a nonenveloped DNA virus (TTV) associated with posttransfusion non-A-G hepatitis.

Five patients with type B or C hepatocellular carcinoma were found to be infected with a nonenveloped DNA virus (TTV) associated with posttransfusion hepatitis of non-A-G etiology. Paired feces and serum samples from these patients were tested for TTV DNA by polymerase chain reaction with seminested primers and their sequences were compared. TTV DNA was detected in sera from all of the patients, while it was detected in feces from three patients, including two with high viral titers in serum. When feces and serum from one patient were subjected to floatation ultracentrifugation in CsCl, TTV in feces banded at a peak density of 1.35 g/cm3 and that in serum at 1.31-1.32 g/cm3. TTV isolates in three pairs of feces and serum had the identical sequence of 222 base pairs. The excretion of TTV into feces indicates that TTV would be transmitted not only parenterally but also nonparenterally by a fecal-oral route.

Base Sequence↗
PubMed1998

[Two cases of spontaneous hemopeumothorax].

We experienced two cases of spontaneous hemopeumothorax. One case was a 17-year-old male with a complaint of back pain. A chest tube for rapid pleural evacuation disclosed hemorrhage as much as 3,000 ml, with drainage volume being gradually decreased. He needed about two month's admission because of complication of pyothorax. The other case was a 46-year-old male with a complaint of chest pain. Chest X-P gave the diagnosis of right hemopeumothorax. Thirty minutes later, he became shock, and five hours later, we performed an emergency intervention of video-assisted thoracoscopic surgery (VATS). Bleeding site of a funicular structure from the parietal pleura was stopped by clipping, with excellent postoperative results. Spontaneous hemopeumothorax is often indicated for early surgical intervention because of association with a high risk of hemorrhagic shock. In such a case, VATS is very helpful.

Adolescent↗
PubMed1998

[Long-term administration study of propiverine hydrochloride (BUP-4 tablets) in pollakiuria and urinary incontinence].

The safety and efficacy of one-year administration of propiverine hydrochloride (BUP-4 tablets) were assessed in facilities affiliated with the Department of Urology of Yokohama City University School of Medicine. Changes in subjective symptoms showed significant improvement in mean frequency of urination in the daytime from 10.3 +/- 4.0 times before administration to 7.1 +/- 2.9 times 1 year after the start of administration, in mean frequency of voiding at night from 4.2 +/- 1.7 times to 2.1 +/- 1.1 times and in mean incidence of urinary incontinence from 2.9 +/- 2.1 times to 0.7 +/- 1.0 times. The final degree of overall improvement rate was 82.0% (41/50 cases). Adverse effects were observed 26 times in 22 patients, the incidence being 15.6% (22/141 cases). They consisted of digestive symptoms in 9.9% (6 events of dry mouth, 4 of constipation, 2 of abdominal discomfort, 2 of diarrhea and 1 of gastritis), urinary tract symptoms in 3.5% (4 of dysuria and 1 of residual urine), abnormal laboratory findings in 1.4% (increase in glutamic-oxaloacetic transaminase, glutamic-pyruvic transaminase or lactate dehydrogenase levels) and others (1.4%). These results provide further evidence of the safety and efficacy of propiverine hydrochloride (BUP-4 tablets) even when administered for a long-term in the treatment of patients with pollakiuria and urinary incontinence.

Administration, Oral↗
PubMed1998

[Waldenström's macroglobulinemia effectively treated with chronic daily oral administration of low-dose etoposide].

A 77-year-old woman with complaints of fever and systemic lymphadenopathy was admitted to our hospital on February 16, 1995. Serum IgM was elevated to 2,097 mg/dl. Lymph node biopsy showed diffuse infiltration with lymphoplasmacytoid cells. Thus, she was diagnosed as having Waldenström's macroglobulinemia. Considering her age and congestive heart failure, she was treated with oral administration of low-dose etoposide (25 mg/day). Splenomegaly and superficial lymphadenopathy disappeared after one course of therapy. Until her death due to pneumonia, complete remission continued for one year without any symptoms and adverse effects except for mild diarrhea. Low-dose etoposide therapy was considered to be well tolerated and useful for elderly patients with Waldenström's macroglobulinemia.

Administration, Oral↗
PubMed1998

Intimal proliferation after stenting reflected by increased stent-to-vessel cross-sectional area ratio: serial intravascular ultrasound study.

Minimizing the extent of neointimal proliferation helps to maintain the maximal vessel lumen after the treatment of stenosis. The present study examined factors influencing the predisposition to neointimal proliferation, which is a consequence of Palmaz-Schatz stenting. Serial intravascular ultrasound examinations of 32 lesions (4 lesions/patient) were performed after stenting and at 6 months follow-up in 8 non-restenotic patients. Vessel, lumen and stent cross-sectional areas (CSA) were measured. Stent-to-vessel CSA ratio at stenting, changes of lumen CSA, vessel CSA and intima CSA (neointimal proliferation) were calculated. Six months after stenting, lumen CSA was reduced corresponding to an increase of intima without change of vessel CSA (without remodeling). Greater stent-to-vessel CSA at stenting was associated with higher neointimal proliferation at follow-up. The proliferative response was the same at all stent edges. Stent CSA was reduced as stent dilation was increased. The stent CSA became smaller but stent shrinkage did not account for late lumen loss. Late lumen loss in stents is the result of neointimal proliferation in cases without restenosis, and a larger stent-to-vessel CSA ratio reflects increased neointimal proliferation, as shown at 6-month follow-up.

Aged↗
PubMed1997

Expression cloning of cDNA encoding a human beta-1,3-N-acetylglucosaminyltransferase that is essential for poly-N-acetyllactosamine synthesis.

The structure and biosynthesis of poly-N-acetyllactosamine display a dramatic change during development and oncogenesis. Poly-N-acetyllactosamines are also modified by various carbohydrate residues, forming functional oligosaccharides such as sialyl Lex. Herein we describe the isolation and functional expression of a cDNA encoding beta-1,3-N-acetylglucosaminyltransferase (iGnT), an enzyme that is essential for the formation of poly-N-acetyllactosamine. For this expression cloning, Burkitt lymphoma Namalwa KJM-1 cells were transfected with cDNA libraries derived from human melanoma and colon carcinoma cells. Transfected Namalwa cells overexpressing the i antigen were continuously selected by fluorescence-activated cell sorting because introduced plasmids containing Epstein-Barr virus replication origin can be continuously amplified as episomes. Sibling selection of plasmids recovered after the third consecutive sorting resulted in a cDNA clone that directs the increased expression of i antigen on the cell surface. The deduced amino acid sequence indicates that this protein has a type II membrane protein topology found in almost all mammalian glycosyltransferases cloned to date. iGnT, however, differs in having the longest transmembrane domain among glycosyltransferases cloned so far. The iGnT transcript is highly expressed in fetal brain and kidney and adult brain but expressed ubiquitously in various adult tissues. The expression of the presumed catalytic domain as a fusion protein with the IgG binding domain of protein A enabled us to demonstrate that the cDNA encodes iGnT, the enzyme responsible for the formation of GlcNAcbeta1 --> 3Galbeta1 --> 4GlcNAc --> R structure and poly-N-acetyllactosamine extension.

Adult↗
PubMed1997

The effect of GABAergic system activity on hyperthermia-induced seizures in rats.

Developing rats were given GABA antagonists and agonist before electrical seizure discharges were induced by heating the brain of a rat with infra-red rays. The thresholds for the GABA antagonist groups were significantly lower than that for the control, and the threshold for the GABA agonist group was significantly higher than that for the control. These results support the hypothesis that reduced GABAergic system activity underlies febrile seizures.

Analysis of Variance↗
PubMed1997

A novel regulatory mechanism in the mitogen-activated protein (MAP) kinase cascade. Role of nuclear export signal of MAP kinase kinase.

Mitogen-activated protein kinase (MAPK) kinase (MAPKK, also known as MEK), a direct activator for MAPK/extracellular signal-regulated kinase, localizes to the cytoplasm excluded from the nucleus during signal transmission. This nuclear exclusion of MAPKK is directed by its nuclear export signal (NES), but its physiological significance has been unknown. We have found that disruption of the NES dramatically potentiates the ability of constitutively active MAPKK to induce morphological changes and malignant transformation of fibroblastic cells. Readdition of the NES sequence reversed the effects induced by the NES disruption. Moreover, we observed that a dramatic increase of activated MAPK in the nucleus was induced by the NES-disrupted MAPKK and that coexpression of MAPK phosphatase-1 (CL-100) or a kinase negative form of MAPK counteracted the phenotypes induced by the NES-disrupted MAPKK, indicating the crucial role of MAPK in the responses. These findings reveal a novel regulatory role of the NES of MAPKK that may be essential for proper signal transductions.

Animals↗
PubMed1997

Carcinoma-associated expression of core 2 beta-1,6-N-acetylglucosaminyltransferase gene in human colorectal cancer: role of O-glycans in tumor progression.

Recently, it was demonstrated that an increased level of NeuNAc alpha2-3Gal beta1-4(Fuc alpha1-3)GlcNAc beta-R (sialyl Le(x)) and NeuNAc alpha2-3Gal beta1-3(Fuc alpha1-4)GlcNAc beta-R (sialyl Le(a)) expression on the surface of colorectal cancer cells is positively correlated with progression of the disease. It has not been determined, however, which type of glycans, N- or O-glycans, is more closely associated with progression when cancer cells express those oligosaccharides. To address this problem, we have examined expression of sialyl Le(a) and sialyl Le(x), those oligosaccharides in O-glycans, and core 2 beta-1,6-N-acetylglucosaminyltransferase (C2GnT) transcripts in colorectal cancer specimens from 46 patients and compared those results with clinicopathological variables. C2GnT is a glycosyltransferase that is responsible for the core 2 branch, which is critical for biosynthesis of sialyl Le(a) and sialyl Le(x) in O-glycans. Sialyl Le(a) and sialyl Le(x) were determined by immunohistochemistry, and C2GnT transcripts were detected by reverse transcription-PCR. Sialyl Le(a) or sialyl Le(x) in O-glycans was assessed by combining immunohistochemistry for sialyl Le(a) or sialyl Le(x) with reverse transcription-PCR for C2GnT. Sialyl Le(a), detected on cancer cells in 74% of patients, was well correlated with lymph node metastasis, whereas sialyl Le(a) and sialyl Le(x) in O-glycans, which were specifically detected in cancer tissues of 50 and 61% of patients, respectively, were closely associated with lymphatic and venous invasion. In addition, C2GnT, which was specifically detected in cancer tissues of 63% of patients, was closely correlated with the vessel invasion, as well as depth of tumor invasion. These results strongly suggest that sialyl Le(a) and sialyl Le(x) in O-glycans and C2GnT, expressed in cancer cells, may play important roles in tumor progression through vessel or direct invasion.

Adult↗
PubMed1997

Human canalicular multispecific organic anion transporter (cMOAT) is expressed in human lung, gastric, and colorectal cancer cells.

Human canalicular multispecific organic anion transporter (cMOAT), a glutathione conjugate membrane transporter, has been isolated from cisplatin-resistant cancer cells and is distributed mainly in normal liver. We analyzed the expression of human cMOAT in 14 lung, 11 gastric, and 9 colorectal non-drug-selected human cancer cells, two multidrug-resistant cells, and one cisplatin-resistant cells, using quantitative RT-PCR and newly developed anti-human cMOAT antibody. All cell lines analyzed here expressed human cMOAT at the level of mRNA and protein, and some of them expressed higher levels of human cMOAT than the cisplatin-resistant cells. The two multidrug-resistant cell lines co-expressed human cMOAT gene and both or either of MRP and MDR1 genes. Immunostaining showed that human cMOAT was predominantly localized to the cytoplasm of these single cells. Our results indicate that human cMOAT is expressed in various human cancer cells including drug-resistant cells.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1997

CRM1 is responsible for intracellular transport mediated by the nuclear export signal.

The discovery of nuclear export signals (NESs) in a number of proteins revealed the occurrence of signal-dependent transport of proteins from the nucleus to the cytoplasm. Although the consensus motif of the NESs has been shown to be a leucine-rich, short amino-acid sequence, its receptor has not been identified. A cytotoxin leptomycin B (LMB) has recently been suggested to inhibit the NES-mediated transport of Rev protein. Here we show that LMB is a potent and specific inhibitor of the NES-dependent nuclear export of proteins. Moreover, we have found a protein of relative molecular mass 110K (p110) in Xenopus oocyte extracts that binds to the intact NES but not to the mutated, non-functional NES. The binding of p110 to NES is inhibited by LMB. We show that p110 is CRM1, which is an evolutionarily conserved protein originally found as an essential nuclear protein in fission yeast and known as a likely target of LMB. We also show that nuclear export of a fission yeast protein, Dsk1, which has a leucine-rich NES, is disrupted in wild-type yeast treated with LMB or in the crm1 mutant. These results indicate that CRM1 is an essential mediator of the NES-dependent nuclear export of proteins in eukaryotic cells.

Animals↗
PubMed1997

Regulation of AP-2-synaptotagmin interaction by inositol high polyphosphates.

The inositol high-polyphosphate series (IHPS) inhibits neurotransmission through binding to the second C2 domain of synaptotagmins I and II(Syt), synaptic vesicle membrane proteins. We have revealed that several proteins, including alpha adaptins which are specific subunits of clathrin assembly protein, AP2, were eluted from mouse brain by affinity elution chromatography from the C2 domains of Syt II-immobilized Sepharose using 50 microM of InsP6. The interaction between Syt II and AP2 was more markedly inhibited by IHPS than by the same concentration of InsP3. Limited digestion of mouse crude synaptosomal fractions with trypsin revealed different cleavage patterns in the presence and absence of 50 microM InsP6. These results suggest that IHPS-binding to the C2B domain of synaptotagmin alters the state of protein-protein interaction including the synaptotagmin-AP2 interaction, possibly resulting in the inhibition of events involved in the synaptic vesicle trafficking.

Adaptor Protein Complex 2↗
PubMed1997

Branched O-linked oligosaccharides ectopically expressed in transgenic mice reduce primary T-cell immune responses.

Core 2 beta-1,6-N-acetylglucosaminyltransferase, C2GnT, is a key enzyme in O-linked oligosaccharide (O-glycan) biosynthesis and the resultant core 2 branch serves as a backbone for additional glycosylation to form oligosaccharide ligands such as sialyl Le(x). Since the expression of C2GnT is highly regulated during T-cell development and increases in pathological conditions such as the Wiskott-Aldrich syndrome, we have generated transgenic mice overexpressing C2GnT in the T-cell lineage. Surprisingly, T lymphocytes in the transgenic mice develop normally, but they exhibit a reduced immune response when assayed by delayed-type hypersensitivity, proliferation upon stimulation and cytokine production. Moreover, T lymphocytes from the transgenic mice adhere much less efficiently to ICAM-1 and fibronectin than do T lymphocytes from non-transgenic mice. These results indicate that overexpression of the core 2 branched O-glycans in T lymphocytes results in reduced immune responses due to impaired cell-cell interaction. Such an impaired immune response may be one of the causes for immunodeficiency in the Wiskott-Aldrich syndrome.

Animals↗
PubMed1997

Relationship between change of movement direction and activity of hippocampal place cells.

Hippocampal neurons which increase their activity when the rat passes through a certain position in the environment are called place cells. This paper describes the relationship between their temporal firing patterns and the behavior of the rat with the aim of characterizing the information they encode. The place field was identified in a circular open field during locomotion rewarded by intracranial self-stimulation of lateral hypothalamus. Detailed analysis of temporal firing patterns shows a correlation between changes in the orientation of movement trajectory and occurrence of the last firing of the burst trains emitted during passage of the animal through the place field. This suggests that some hippocampal neurons may encode the spatial information about the orientation changes in the place field.

Animals↗
PubMed1997

Inositol-1,3,4,5-tetrakisphosphate binding sites in control and ras-transformed NIH/3T3 fibroblasts.

Inositol-1,3,4,5-tetrakisphosphate (Ins(1,3,4,5)P4) binding properties were investigated in NIH/3T3 fibroblasts and its ras-transformant (DT cells), in which inositol tetrakisphosphates induce Ca2+ influx. [3H]-Ins(1,3,4,5)P4 bound to membranes of both types of cells with Kd values of 10.6 and 8.6 nM, respectively. The rank order of inositol polyphosphates for displacing [3H]Ins(1,3,4,5)P4 in DT cells was Ins(1,3,4,5)P4 > inositol-1,3,4,5,6-pentakisphosphate > inositol hexakisphosphate > inositol-1,4,5-trisphosphate. This order is similar to that reported in two Ras-GTPase-activating proteins, GAP1IP4BP and GAP1m, which are also the Ins(1,3,4,5)P4 binding proteins. Northern blot analysis revealed that NIH/3T3 and DT cells expressed mRNA species that were hybridizable with GAP1m cDNA. These results suggest that parental and ras-transformed NIH/3T3 fibroblasts possess GAP1-like proteins, which may be responsible for triggering inositol tetrakisphosphate-dependent Ca2 influx.

3T3 Cells↗