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Biomedical subjects

K Fujimoto

Publications and source records attributed to K Fujimoto.

At least 469 records · Page 26Linked to original sources
PubMed1995

[Septic lung caused by methicillin-resistant Staphylococcus epidermidis].

A 55-year-old man was admitted to our department one month after resection of rectal carcinoma, with complaints of fever and general malaise. Shock developed rapidly after admission. The chest X-ray film and computed tomography showed diffuse small nodular shadows and bilateral pleural effusion. Septic lung caused by Methicillin-resistant Staphylococcus epidermidis (MRSE) was diagnosed from the results of a bacteriological study. This bacteria is a Coagulase Negative Staphylococcus (CNS). Chemotherapy with Minocycline and Cefotiam was effective. Characteristic radiologic features of this case may be related to the early stage of adult respiratory distress syndrome (ARDS) and septic pulmonary microembolism.

Anti-Bacterial Agents↗
PubMed1994

Nerve growth factor treatment induces high-potassium-evoked calcium-dependent acetylcholine release in cultured embryonic rat septal cells.

The effects of dibutyryl cAMP (dbcAMP) and nerve growth factor (NGF) on acetylcholine (ACh) release from primary cultured cells of embryonic rat septum were studied. Both dbcAMP and NGF increased the activity of choline acetyltransferase and contents of intracellular and spontaneously released ACh without affecting the total protein content. High-potassium-evoked ACh release was observed in NGF-treated cells but not in untreated and dbcAMP-treated cells. These results indicate that NGF induces cholinergic maturation from induction of the ACh-synthetic enzyme to the excitation-secretion processes.

Acetylcholine↗
PubMed1994

[Arterial infusion chemotherapy with human tumor necrosis factor (TNF): an experimental study using rabbits bearing VX2 tumor].

To evaluate the direct effects of TNF on tumor vessels, three groups of Japanese white rabbits bearing VX2 tumor received 5000 U, 25000, U, and 5000 U of TNF respectively. Angiograms were obtained before, and at 1, 15 and 30 minutes after arterial TNF injection. At 1 minute after TNF injection, dilated tumor vessels and dense tumor stains, depending on the dose of TNF, were demonstrated. At 30 minutes after injection these findings had disappeared However, there were no changes in normal vessels. It is suggested that arterial TNF injection influenced tumor vessels without damaging on normal vessels, indicating that it is effective as cancer therapy.

Animals↗
PubMed1994

Site-directed mutagenesis of the histamine H1 receptor: roles of aspartic acid107, asparagine198 and threonine194.

Based on structural comparison with other biogenic amine receptors and the histamine H2 receptor, it has been suggested that in the human histamine H1 receptor, Asp107, Thr194, and Asn198 are the residues involved in binding of histamine. We therefore used site-directed mutagenesis to investigate the roles of these three amino acid residues. Asp107 was essential for both agonist and antagonist binding. Asn198 was necessary for agonist but not for antagonist binding. Thr194 was not important for either type of binding. A good correlation was found between agonist binding and receptor activation for all the wild-type and mutant receptors. The results show that the histamine H1 receptor recognizes and is activated by histamine through the interactions of Asp107 and the amino group, and Asn198 and the imidazole ring.

Amino Acid Sequence↗
PubMed1994

Location of active sites of NiFe hydrogenase determined by the combination of multiple isomorphous replacement and multiwavelength anomalous-diffraction methods.

The active centers of NiFe hydrogenase from Desulfovibrio vulgaris Miyazaki F have been located in the electron-density map calculated at 4 A resolution. The electron-density map based on five heavy-atom derivatives showed four strong peaks which were clearly distinguished from the protein region. These strong densities have been successfully assigned to three iron-sulfur clusters and one Ni atom by a difference Fourier technique with coefficients of the best phases from the multiple isomorphous replacement (MIR) method and structure factors obtained at five wavelengths (1.040, 1.487, 1.730, 1.743 and 1.750 A) with the use of a synchrotron radiation source. Four active centers are approximately lined up at a distance of ca 13 A, which seems reasonable if they are connected with the electron-transfer chain.

Journal Article↗
PubMed1994

Phorbol ester stimulates acetylcholine synthesis in cultured endothelial cells isolated from porcine cerebral microvessels.

Acetylcholine (ACh) is one of the factor which induces vasodilation through the release of endothelium-derived relaxing factor. The aim of this study was to clarify whether endothelial cells can synthesize ACh and the types of substance which regulate the synthesis of ACh in endothelial cells. We determined the ACh content of endothelial cells isolated from porcine cerebral microvessels and of the culture medium. ACh was detected in the medium after 12 h incubation in the presence of diisopropylfluorophosphate, a non-specific cholinesterase inhibitor, and increased linearly up to 24 h. Phorbol 12-myristate 13-acetate (PMA, 10(-7) M) increased the ACh content of the medium in a dose-dependent manner. The effect of PMA was most apparent between 12 and 24 h after treatment, and was inhibited by cycloheximide. Calphostin C, a specific inhibitor of protein kinase C (PKC), did not inhibit the effect of PMA. Dioctanoyl glycerol, a specific activator of PKC, did not increase the intracellular ACh content or the amount released into the culture medium. ACh synthesis was not inhibited by bromoacetylcholine, a specific inhibitor of choline acetyltransferase (ChAT). PMA treatment did not affect the specific activity of ACh synthesis in endothelial cells. These data show that endothelial cells are able to synthesize ACh, and that ACh synthesis is up-regulated by PMA through the PKC independent mechanism via protein induction. The enzyme which synthesizes ACh in endothelial cells is not ChAT. The increase in ACh synthesis induced by PMA may not be due to induction of the ACh synthetic enzyme.

Acetylcholine↗
PubMed1994

Gene sequence, purification and characterization of N-acetyl-beta-glucosaminidase from a marine bacterium, Alteromonas sp. strain O-7.

The gene (cht60) encoding N-acetyl-beta-glucosaminidase (Cht; EC 3.2.1.30) from the marine bacterium Alteromonas sp. strain O-7 was cloned into pUC18 in Escherichia coli JM109. The nucleotide (nt) sequence of cht60 was determined. A 1797-bp open reading frame encoded a polypeptide of 598 amino acids (aa) (M(r) 64,535). The aa sequence of the cloned enzyme (Cht60) deduced from the nt sequence showed no significant sequence homologies with available aa sequences from databases. Cht60 was purified from the periplasmic fraction of E. coli cells carrying pCHT982. The enzyme was most active towards p-nitrophenyl-N-acetyl-beta-D-glucosaminide(PNP-beta-GlcNAc) and diacetylchitobiose. The optimum pH and temperature of the enzyme were pH 7.5 and 37 degrees C, respectively. The N-terminal 11 aa residues of Cht60 were sequenced, and the location of the signal peptide cleavage site was clarified.

Acetylglucosaminidase↗
PubMed1994

Two different cellular redox systems regulate the DNA-binding activity of the p50 subunit of NF-kappa B in vitro.

The NF-kappa B/Rel/Dorsal (NRD) transcription factor family binds target DNA sequences through their conserved N-terminal basic region that contains a single cysteine residue flanked by basic residues. This cysteine residue plays a critical role in the regulation of the DNA-binding activity of NRD members, since chemical modifications of this residue modulate the DNA-binding activity of NRD members. Here we show that cellular factors regulate the DNA-binding activity of NRD members in vitro by reduction-oxidation (redox) mechanisms. Two cellular redox systems, thioredoxin/thioredoxin reductase and apurinic/apyrimidinic endonuclease (also called Redox factor-1), independently, as well as, synergistically stimulate the DNA-binding activity of bacterially synthesized (recombinant) p50, one of the subunits of NF-kappa B that is a major NRD factor inducible in various types of cells. Since the mutation of the conserved residue (Cys61) in the N-terminal basic region of p50 impairs the stimulation of p50 DNA-binding activity by these redox factors, the regulation of p50 DNA-binding activity by these redox factors is mediated through this cysteine residue. It is, therefore, possible that these two cellular redox systems could play independent, as well as synergistic roles in the regulation of NF-kappa B functions in vivo through the redox control of their DNA-binding activity.

Amino Acid Sequence↗
PubMed1994

Molecular cloning of the human histamine H1 receptor gene.

The human histamine H1 receptor gene, an intron-lacking gene, was isolated with bovine H1 receptor cDNA [Yamashita, M., Fukui, H., Sugama, K., Horio, Y., Ito, S., Mizuguchi, H., and Wada, H. (1991) Proc. Natl. Acad. Sci. USA 88, 11515-11519] used as a probe. The receptor protein deduced from the nucleotide sequence of this gene was composed of 487 amino acid residues with a calculated Mr of 55,781 and possessed characteristic properties of GTP binding protein-coupled receptors. At the 5' flanking region of the human H1 receptor gene, we located potential TATA box and CACCC sequences, AP1 binding site-like sequences, glucocorticoid responsive element-like sequences, and other binding sequences for inducers. Northern blot analysis showed that H1 receptor mRNAs visualized as two bands with 3.0-kilobase and 3.5-kilobase nucleotides were expressed in peripheral tissues such as placenta, lung, skeletal muscle, and kidney and that only one species with 3.5-kilobase nucleotides was present in the brain. H1 receptor mRNA was most abundant in the placenta. The human H1 receptor gene was mapped to the chromosome 3p25 by the fluorescence in situ hybridization method.

Amino Acid Sequence↗
PubMed1994

Activation of human neutrophils by Arg-Gly-Asp-Ser immobilized on microspheres.

The adhesive interaction of cells with extracellular matrix components is essential for a variety of cellular functions, and is frequently mediated by a tetra peptide, Arg-Gly-Asp-Ser (RGDS), located within fibronectin and other proteins. In this study, the RGDS-mediated activation of polymorphonuclear leukocytes accompanied by phagocytosis was investigated using monodisperse polymeric microspheres carrying RGDS. The parent and Arg-Gly-Glu-Ser (RGES)-carrying microspheres, which have no adhesion activity, were employed as controls. The ingestion of microspheres into PMN was not enhanced by immobilizing RGDS. However, PMNs exhibited unique oxygen consumption and enhanced liberation of reactive oxygen when RGDS-carrying microspheres were phagocytosed. These PMN responses disappeared with the addition of soluble RGDS. Furthermore, cytochalasin D, which inhibits actin polymerization, showed a marked inhibitory effect on oxygen consumption in the RGDS-carrying microsphere system, as compared with those in other systems. These findings show that RGDS-carrying microspheres induced the biospecific activation of PMNs by the signal transduction via RGDS-integrin binding without alteration in the degree of phagocytosis.

Amino Acid Sequence↗
PubMed1994

Effects of the centrally acting cholinesterase inhibitors tetrahydroaminoacridine and E2020 on the basal concentration of extracellular acetylcholine in the hippocampus of freely moving rats.

The effects of the centrally acting cholinesterase (ChE) inhibitors, tetrahydroaminoacridine (THA) and E2020 (1-benzyl-4-[(5,6-dimethoxy-1-indanon)-2-yl] methylpiperidine hydrochloride), potential drugs for the treatment of senile dementia, on the basal extracellular acetylcholine (ACh) concentration in the hippocampus of freely moving rats, were determined using a microdialysis technique without the use of a ChE inhibitor in the perfusion fluid and a sensitive RIA. The mean (+/- SEM) basal ACh content in the perfusate was 103.1 +/- 3.6 fmol/sample collected over 30 min when microdialysis probes with a length of 3 mm dialysis membrane were used. The content of ACh decreased to an almost undetectable level upon perfusion of magnesium, suggesting that, in the present study, most of the ACh detected in the perfusates was due to cholinergic neuronal activity. THA (1.65 mg/kg, i.p.) produced an insignificant increase in the extracellular ACh concentration, but a dose of 5 mg/kg, i.p. caused a prolonged and significant 5.5-fold increase from the control value. E2020 (0.65 and 2 mg/kg, i.p.) produced significant, prolonged and dose-dependent increases (4 and 12 times the control value, respectively), the peak effect occurring within 1 h. Perfusion with 10 mumol/l physostigmine produced an about 30-fold increase of ACh output, suggesting that the basal extracellular ACh concentration is highly dependent on ChE activity. When ChE was inhibited locally by perfusion with physostigmine, THA (5 mg/kg) produced a transient and, at its maximum, a 1.42-fold increase in extracellular ACh concentration.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1994

Distribution of metastatic lymph nodes in colorectal cancer by the modified clearing method.

PURPOSE: The aim of this study was to clarify the distribution of lymph node metastasis in colorectal cancer. We also examined the relationship between the primary tumor (T) and the regional node (N) categories of the TNM (primary tumor, regional nodes, metastasis) classification. METHOD: Lymph nodes of surgical specimens in 311 consecutive patients with colorectal cancer were studied using the modified clearing method. RESULTS: Lymph node metastasis was seen in 59.2 percent of the total cases. The upward metastasis rate was 30.7 percent. In the longitudinal spread, most of the lymph node metastasis was seen within 10 cm. On the oral side in rectal cancer, there was no metastasis beyond 4 cm. The lateral metastasis rate in rectal cancer was 8.8 percent and in the lower rectum, the rate of cancer within 6 cm from the anal verge or beyond pT3 was much higher. CONCLUSION: In the TNM classification, there was no significant difference between colon and rectal cancer except pT1 with rectal cancer. In the lower rectal cancer within 6 cm from the anal verge or beyond pT3, there is a high risk of lateral metastasis, and lateral lymph node dissection or radiation therapy should be performed.

Anus Neoplasms↗
PubMed1994

Role of histamine receptors in intestinal repair after ischemia-reperfusion in rats.

BACKGROUND/AIMS: Previously, we showed that an elevated production of histamine promotes the healing of injured intestinal mucosa after ischemia-reperfusion. The aim of the present study was to determine whether histamine-mediated repair of the intestinal mucosa after ischemia-reperfusion involves the engagement of H1 or H2 receptors. METHODS: The superior mesenteric artery was occluded for 15 minutes followed by reperfusion, and H1- or H2-receptor antagonists were infused intraduodenally. After ischemia-reperfusion, ornithine decarboxylase activity in the jejunal mucosa and lipid transport to mesenteric lymph were examined. RESULTS: In jejunal mucosa, ornithine decarboxylase activity markedly increased at 6 hours after reperfusion and remained elevated at 48 hours. The ischemia-reperfusion-induced increase in ornithine decarboxylase activity was attenuated (in a dose-dependent manner) by an H1-receptor antagonist (chlorpheniramine maleate) but not by an H2 antagonist (cimetidine). Intraperitoneal injection of an H3 antagonist (thioperamide) increased histamine output in mesenteric lymph and stimulated intestinal ornithine decarboxylase activity. Transport of dietary lipid into mesenteric lymph was depressed 24 hours after an ischemic insult, yet it returned to the normal level 48 hours after ischemia-reperfusion. The recovery of the lipid transport normally observed at 48 hours after ischemia-reperfusion was attenuated by the H1 antagonist. CONCLUSIONS: The beneficial effects of histamine on the repair of intestinal mucosa after ischemia-reperfusion results from the engagement and activation of the H1 receptor.

Animals↗
PubMed1994

Effect of ageing on erythrocyte aldose reductase and sorbitol dehydrogenase activity.

We measured erythrocyte aldose reductase and sorbitol dehydrogenase activity in erythrocytes in healthy individuals aged from 16 to 91 years to determine the mechanism of age-dependent sorbitol accumulation. Erythrocyte aldose reductase activity increased significantly with age but ageing had no effect on sorbitol dehydrogenase activity. Age and the aldose reductase/sorbitol dehydrogenase ratio were positively correlated. These findings suggest that an increase in the ratio of aldose reductase to sorbitol dehydrogenase may contribute to the tissue accumulation of sorbitol in the elderly and may be a mechanism of a disease that is common in elderly individuals.

Adolescent↗
PubMed1994

Influence of the structure of support microspheres on leucocyte activation by RGDS-carrying microspheres.

A cell adhesive peptide, Arg-Gly-Asp-Ser (RGDS), enhances leucocyte response to stimuli when insolubilized or conjugated with proteins. In order to investigate the contribution of the microsphere structure to leucocyte response. RGDS was immobilized onto several polymeric microspheres. The respiratory burst of polymorphonuclear leucocytes (PMNs) contacting contacting microspheres was enhanced by RGDS in cases where it was immobilized on polystyrene and, more effectively, a positively charged one. This was not observed in polyacrylamide-based or negative-charged microsphere systems. These results demonstrate that the property of supports strongly affects the regulation of the PMN response via an adhesive interaction.

Amino Acid Sequence↗