Biomedical subjects

T Okada

Publications and source records attributed to T Okada.

At least 469 records · Page 26Linked to original sources

PubMed1996

[Emergency myectomy in a patient with hypertrophic obstructive cardiomyopathy complicated with left heart failure and cardiac arrest].

Major cause of death in HOCM is sudden death due to ventricular arrhythmias, and only 10% of the death is caused by congestive heart failure. We report a 38-year-old woman of HOCM complicated with lung edema and cardiac arrest due to acute left heart failure. Intraventricular pressure gradient showed 125 mmHg in previous study, and echocardiogram demonstrated evidences suggestive of terminal-staged HOCM. After unsuccessful attempts of intravenous propranolol administration, emergency myectomy of left ventricular outflow tract was carried out. Postoperative course was uneventful, and intraventricular pressure gradient was relieved. The patient is now asymptomatic without medication after 1 years of operation. This case suggests that emergency myectomy may be a choice to relieve refractory congestive heart failure in patient with HOCM.

Adult↗

PubMed1996

[Charge selectivity of peritoneal transport in CAPD patients under stable states and during peritonitis].

To investigate charge selectivity of peritoneal transport in CAPD, dialysate/plasma concentration ratios (D/P) were calculated for creatinine (Cr) and 3 amino acids with almost the same molecular weight but quite different charges: glutamic acid (Glu: negatively charged), glutamine (Gln: near neutrally charged) and lysine (Lys: positively charged). The study population consisted of 23 stable patients and 11 patients with peritonitis on CAPD. In the stable patients, the samples of dialysate were taken at 2 and 4 hours and blood samples were obtained at 4 hours after the infusion of 2 liters of 2.27 or 2.5% glucose CAPD dialysate; the samples of patients with peritonitis were obtained at 4.1 +/- 1.1 hours of dwell time. In stable patients, D/P of Glu was much lower than the values for Gln, Lys and Cr at both 2 and 4 hours (p < 0.01), and D/P of Lys was significantly lower than that of Gln (p < 0.01). There was no significant difference in D/P between Gln and Cr. In patients with peritonitis, D/P of Glu was also significantly lower than the values for Gln and Cr (p < 0.05 and p < 0.01), however, no significant differences were found between D/P of Lys and the values of Glu and Gln. Ratios of both [D/P Glu]/[D/P Lys] and [D/P Glu]/[D/P Gln] were much higher in peritonitis patients than in stable patients. In conclusion, peritoneal transport in stable CAPD patients shows charge selectivity, and the order of molecular charge for transperitoneal mobility among small solutes is neutral > positive > negative. The selectivity, however, is decreased or lost during peritonitis.

Adult↗

PubMed1996

[A clinical evaluation of azithromycin in the treatment of pediatric infection].

Fine granule preparation of azithromycin (AZM), a new macrolide antibiotic, was given to treat various infections in pediatric patients. Efficacies of AZM in a total of 21 patients (tonsillitis in six, bronchitis in five, pneumonia in five, impetigo contagiosa in three, staphylococcal scalded skin syndrome in one and bacterial enterogastritis in one) were rated "excellent" in 11 patients and "good" in eight. The remaining two cases were not included in the evaluation. AZM eradicated all strains of infection-causative bacteria identified in the 21 patients: Staphylococcus aureus in two, Streptococcus pneumoniae in four, Moraxella (Branhamella) catarrhalis in four, Haemophilus influenzae in six, Haemophilus parainfluenzae in three and Mycoplasma pneumoniae in one. One patient complained of mild diarrhea, while two patients showed increases in eosinophils as abnormal laboratory changes.

Anti-Bacterial Agents↗

PubMed1996

[Pharmacokinetic and clinical evaluations of azithromycin in the pediatric field].

Azithromycin (AZM), an oral macrolide antibiotic drug, was studied for its efficacy and pharmacokinetics in the treatment of pediatric patients with respiratory tract infections. The results of the study are presented. Fifteen pediatric patients in an age range between 1 and 10 years were given 8.9 to 14.7 mg/ kg body weight of AZM once daily for 3 to 4 days. Pharmacokinetics of AZM in three patients were examined. AZM concentration in plasma was 0.037 microgram/ml at 72 hours after final dosing, while urine concentration was 10.9 micrograms/ml measured during a period between 72 and 96 hours post-dosing. Fourteen patient cases were included in analysis of drug efficacy for AZM. AZM was found "markedly effective" in all seven patients with pneumonia, and "effective" in all three patients with acute bronchitis, two patients with mycoplasmal pneumonia, and one patient with tonsillitis. In one patient with mycoplasmal bronchitis, AZM was found slightly effective. The efficacy rate was 92.9% (13/14). The study found one case of side effect, moderate diarrhea. No laboratory abnormality was documented. In conclusion, an antibiotic AZM was found useful in a treatment of pediatric respiratory tract infections.

Anti-Bacterial Agents↗

PubMed1996

[Detection of numerical chromosomal aberrations in hematopoietic malignancy by in situ hybridization on bone marrow aspirate paraffin sections].

We evaluated the usefulness of in situ hybridization (ISH) with chromosome specific DNA probe on paraffin sections of bone marrow aspirates. Twenty cases of hematopoietic malignancy and eight control cases of non-hematopoietic malignancy were examined with centromere-specific probes for chromosomes 8 and 17. In the eight control cases, the mean rates of cells with more than three hybridization signals were 1.13 (2SD = 1.90) for chromosome 8, and 0.88 (2SD = 2.25) for chromosome 17. The mean rates plus 2SD were 3.03 for chromosome 8, and 3.19 for chromosome 17. Therefore, we defined cases of more than 4.0% of cells showing more than three hybridization signals per nuclei as having a numerical abnormality (trisomy). We compared these results with conventional cytogenetic results by karyotype analysis. In twenty hematopoietic malignancy cases, three cases demonstrated trisomy 8 by ISH. Two cases also demonstrated this abnormality by karyotype analysis, but one case showed no abnormality by karyotype analysis. While trisomy 17 detected in one case that did not demonstrate numerical abnormality, only structural abnormality by karyotype analysis. The rate of discrepancy between results of ISH analysis and those of karyotype analysis was only 5% (2/40) for both chromosomes. In five cases, re-examinations were performed within three months. In one case, we could not obtain adequate material for karyotype analysis. However, this case showed trisomy 8 by ISH. Structural chromosomal abnormalities such as translocation or deletion could not be detected by this ISH analysis with centromere-specific probes. However, this method has the advantage result that we can perform retrospective assessments, do not need to culture cell, and can compare with pathological findings. Thus, we conclude that ISH analysis with paraffin sections of bone marrow aspirates will provide more useful information by combining ISH analysis and karyotype analysis.

Bone Marrow Cells↗

PubMed1995

Nerve growth factor prevents apoptosis of rat peritoneal mast cells through the trk proto-oncogene receptor.

We investigated the inhibitory activity of nerve growth factor (NGF) on apoptosis of rat peritoneal mast cells (PMCs) and compared it with that of recombinant stem cell factor (rSCF), which is a mast cell growth factor. When PMCs were incubated up to 72 hours in the presence of control medium, internucleosomal fragmentation of DNA indicating apoptosis was detected by agarose gel electrophoresis and flow cytometry. The aged PMCs showed morphological changes typical for apoptosis, such as chromatin condensation and loss of microvilli of the cell membrane. Addition of NGF or rSCF prevented development of the characteristic DNA fragmentation and decreased the proportion of apoptotic cells with low DNA content values in a dose-dependent manner. Polyclonal antibody to NGF completely abolished the inhibitory activity of NGF but not of rSCF. NGF-induced PMCs were in the G0/G1 phase of the cell cycle, but rSCF transited them from the G0/G1 phase to the S/G2M phase, suggesting that NGF, unlike rSCF, may have no proliferation activity to PMCs. By flow cytometric analysis with antibodies to NGF receptors p75LNGFR and p140trk, we defined that PMCs expressed p140trk but not p75LNGFR. Addition of herbimycin A or K-252a, tyrosine kinase inhibitors, to NGF resulted in blockage of the NGF-induced p140trk phosphorylation and restriction of the inhibitory activity of NGF on apoptosis of PMCs. These results indicated that NGF suppressed apoptosis of rat PMCs through the p140trk tyrosine phosphorylation and possessed no proliferative activity. Thus, NGF may act as a key factor to promote survival of connective tissue-type mast cells.

Animals↗

PubMed1995

Adhesion molecules involved in the binding of murine myeloma cells to bone marrow stromal elements.

In previous work, we reported the development of the B9/BMI syngeneic murine bone marrow metastasis model. Interleukin (IL)-6-dependent, IL-I-producing B9/BMI cells, which preferentially home to and colonise the vertebral and femoral marrow after i.v. injection, exhibit striking similarity in cell surface phenotype to human myeloma cells, especially the expression of 3 adhesion molecules, CD44, VLA-4 and ICAM-I. Because the haematopoietic microenvironment consists of different cell types, such as endothelial cells, fibroblasts, adipocytes and macrophages, we investigated the functional significance of these adhesion molecules in heterotypic binding assays between B9/BMI cells and a newly established bone marrow-derived endothelial cell line (BMEC), a fibroblastoid pre-adipocyte cell line (BMS2.2) and primary bone marrow-derived macrophages. B9/BMI cells adhered well to all stromal elements: a combination of monoclonal antibodies (MAbs) against CD44 and VLA-4 significantly inhibited the adherence of B9/BMI cells to BMEC and BMS2.2 cells, whereas binding of B9/BMI cells to macrophages was partially blocked with an anti-ICAM-I MAb. Our results implicate multiple recognition mechanisms, including those involving CD44, VLA-4 and ICAM-I, in the retention of B9/BMI cells in the bone marrow.

Animals↗

PubMed1995

A case of liposarcoma originating in the chest wall.

We encountered and reported one such rare case of liposarcoma which originated in the chest wall. A 60-year-old man came to our hospital with the chief complaint of a phyma in the right anterior chest wall. On palpation, a hard and non-mobile phyma measuring 3 x 3 cm was felt in the chest wall. Chest CT showed a phyma measuring 2.2 x 1.5 cm in the right anterior chest. The periphery of the phyma was smooth, and had a well-defined boundary with the surrounding tissues. Ultrasonic examination revealed that the tumor existed between the major and minor pectoral muscles. The inside of the tumor was nearly uniform, and showed low echo. Punctured cytological examination revealed scattered atypical cells with spindle, foamy or vacuolar sporophores on the mucoid matrix. A fat staining examination revealed lipoblasts with oil red-positive granules. Based on these findings, the patient was diagnosed as having myxoid type liposarcoma. Operation consisted of resection of the skin, subcutaneous tissues, mammary gland, part of major and minor pectoral muscles, the fourth and fifth ribs and pleura. The Reconstruction of the chest wall was performed for defects in the ribs and pleura using Marlex Mesh. Histopathological findings revealed that the tumor was myxoid type liposarcoma.

Humans↗

PubMed1995

Inhibition of anti-V3 domain antibody binding to human immunodeficiency virus type-1-infected cells by sulfated polysaccharides.

The third variable domain (V3 domain) of the human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein gp120 is an immunodominant region. Anti-V3 domain antibodies neutralize both HIV-1 infection and syncytium formation. The V3 domain has a high density of positive charge which is a potential binding site for anti-HIV-1 sulfated polysaccharides. To investigate the inhibitory effect of sulfated polysaccharides on the binding of anti-V3 domain antibody, fluorescence-activating cell sorting analysis was performed using two kinds of antibodies, NEA9284 (purified, 0.25 micrograms/ml) and 0.5 beta (ascite, 2.0 mg/ml), and HIV-1-infected CEM cells. When the binding assay with a 1:100 dilution of each antibody was performed in the presence of dextran sulfate, heparin, and inositol hexasulfate at concentrations which are antiviral, the compounds did not inhibit the binding of either antibody. As the antibody concentration was decreased with higher dilution, dextran sulfate was able to reduce antibody binding by 50-60%. Thus, antagonism of anti-V3 domain antibody binding by sulfated polysaccharides is not as extensive as reported previously by several groups.

Amino Acid Sequence↗

PubMed1995

Difference between cancer cells and the corresponding normal tissue in view of stereoselective hydrolysis of synthetic esters.

This study has aimed at taking information necessary for design of anticancer prodrugs modified with chiral acyl group, especially about the effect of chirality of the acyl group on its enzymic removal in specific cells. Thus, 13 species of chiral esters were synthesized and stereoselectivity in their enzymic hydrolysis was investigated with six cancer cell lines, solid tumors, and the corresponding normal tissues. Cultured cancer cells from rat liver, pancreas, and muscle hydrolyzed the R enantiomer of (+/-)-ethyl 2-methoxy-2-phenylacetate (3c) more preferentially than its antipode, whereas this stereoselectivity was reversed in the reaction by homogenate of the corresponding normal tissue of rat. The difference in stereoselectivity between cancer cells and normal tissue was also found in the hydrolysis of other esters including those of actual anticancer agents, p-hydroxyaniline mustard and 5-fluorouridine. The investigation was expanded to real tumor to show that the degree of stereoselectivity or the hydrolytic activity was significantly different between a human brain tumor and its surrounding normal tissue for such substrates as (+/-)-ethyl 2-phenoxypropanoate and N-trifluoroacetylphenylalaninate. The esterases of rat liver cancer cells (Anr4) and normal rat liver gave different band patterns in active staining after gel electrophoresis. The enzymes were fractionated by ion exchange column chromatography and then tested on their stereoselectivity against (+/-)-3c. Comparison of the results and electrophoretograms of the fractions suggests that esterases with different stereoselectivity are expressed in different ways by normal and cancer cells. These results show that stereoselectivity in enzymic hydrolysis of some synthetic chiral esters is different between cancer and normal cells, leading to the possibility that specific activation of ester-type anticancer prodrugs in cancer cells would be controlled by the chiral structure of the acyl group.

Animals↗

PubMed1995

Protein kinase Byr2 is a target of Ras1 in the fission yeast Schizosaccharomyces pombe.

Conservation of the structure and function of Ras proteins has been observed in a variety of eukaryotic organisms. However, the nature of their downstream effectors appears to be quite divergent; adenylyl cyclase and a protein kinase Raf-1, which do not share any structural homology with each other, are effectors of Ras in the budding yeast and in higher organisms, respectively. We show here that a protein kinase Byr2, which has been known to act downstream of Ras1 in a mating pheromone signal transduction system of Schizosaccharomyces pombe, binds directly to Ras proteins in a GTP-dependent manner. The region of Byr2 responsible for the Ras binding was mapped by a gene deletion analysis to its N-terminal segment of 206 amino acid residues, which does not possess any significant homology with the other effectors of Ras. The affinity of the Byr2 N terminus for Saccharomyces cerevisiae Ras2 was determined by measuring its activity to competitively inhibit Ras-dependent adenylyl cyclase activity and found to be comparable with those of yeast adenylyl cyclase and human Raf-1, with a dissociation constant (Kd) of about 1 nM. Furthermore, Byr2 inhibited a Ras GTPase-activating activity of Ira2, a S. cerevisiae homologue of neurofibromin. These results indicate that Byr2 is an immediate downstream target of Ras1 in S. pombe.

Adenylyl Cyclases↗

PubMed1995

Repression of transient expression by DNA methylation in transcribed regions of reporter genes introduced into cultured human cells.

We developed a convenient method to methylate all CpG dinucleotides in both strands in a selected region of a plasmid, and investigated the effect of DNA methylation in the transcribed regions of reporter genes on the transient expression in HeLa cells. In a construct containing the chloramphenicol acetyltransferase (CAT) gene linked to the SV40 early promoter, methylation in the CAT structural gene repressed CAT activity. Methylation in the transcribed region of the Escherichia coli lacZ gene driven by the human cytomegalovirus immediate early promoter also inhibited expression of beta-galactosidase activity. These results suggest that methylation in the transcribed region as well as promoter methylation may affect transcription.

Chloramphenicol O-Acetyltransferase↗

PubMed1995

Stereoselective hydrolysis of xenobiotic esters by different cell lines from rat liver and hepatoma and its application to chiral prodrugs for designated growth suppression of cancer cells.

Stereoselectivity in the hydrolysis of racemic ethyl 2-phenylacetate derivatives by cultured cells of noncancerous cell lines from rat liver (BRL, BRL 3A, Clone 9, and ARLJ301-3), spontaneously or oncogene transformed rat liver cell lines (ARLJ301-3TR1, Anr4, Anr9-1, and Anr13-1), and cancer cell lines from rat hepatoma (H4-II-E, McARH7777, and MH1C1) and sarcoma (XC) was studied. A strong (R)-enantiomer preference was found in the hydrolysis of ethyl 2-hydroxy-(2c) and 2-methoxy-2-phenylacetate (3c) by the noncancerous and oncogene-transformed cells and an (S)-enantiomer preference for ethyl N-acylphenylalaninates with all the present cell lines. These inclinations were, however, not recognized with ethyl 2-methoxy-2-phenylpropanoate and ethyl N-difluoroacetyl- or N-trifluoroacetylphenylalaninate. Moreover, the R preference for 3c was reversed in the reaction by hepatoma cells. Thus, the stereoselectivity is influenced by both structure of acyl group and species of cell lines. The hepatoma cells were considerably different from the noncancerous or oncogene-transformed cells in stereoselectivity. This fact was consistent with the order of colony formation in soft agar cultures (index of malignancy) and the resemblance in actively stained esterase patterns in gel electrophoresis. The stereoselective hydrolysis leads to cell-specific activation of anticancer prodrugs. This has been confirmed for the first time by the stereoselectivity of Anr4 and H4-II-E cells in the hydrolysis of a chiral mustard ester, bis(2-chloroethyl)aminophenyl 2-methoxy-2-phenylacetate (14) and by the difference of IC50 values of (R)- and (S)-14 against the two cell lines.

Agar↗

PubMed1995

Surface and blood-contacting properties of alkylsiloxane monolayers supported on silicone rubber.

Self-assembled monolayers of alkylsiloxanes supported on polydimethyl siloxane (PDMS) rubber were used as model systems to study the relation between blood compatibility and surface chemistry. The inner lumen of PDMS tubes was first treated with an oxygen plasma. The resultant oxidized surfaces were postderivatized by reacting them with alkyltrichlorosilanes to form the monolayer films. The chemical properties of the monolayers were controlled by varying the head-group chemical compositions. Surface derivatization was verified using variable-angle X-ray photoelectron spectroscopy (XPS or ESCA). Blood compatibility was evaluated using a canine ex vivo arteriovenous series shunt model. Surfaces grafted with hydrophobic head-groups as -CH3 and -CF3 had significantly lower platelet and fibrinogen deposition than the surfaces composed of hydrophilic groups such as -CO2CH3, -(CH2CH2O)3COCH3, and -(OCH2CH2)3OH.

Animals↗

PubMed1995

A cDNA clone encoding an IgE-binding protein from Brassica anther has significant sequence similarity to Ca(2+)-binding proteins.

Thirteen cDNA clones encoding IgE-binding proteins were isolated from expression libraries of anthers of Brassica rapa L. and B. napus L. using serum IgE from a patient who was specifically allergic to Brassica pollen. These clones were divided into two groups, I and II, based on the sequence similarity. All the group I cDNAs predicted the same protein of 79 amino acids, while the group II predicted a protein of 83 amino acids with microheterogeneity. Both of the deduced amino acid sequences contained two regions with sequence similarity to Ca(2+)-binding sites of Ca(2+)-binding proteins such as calmodulin. However flanking sequences were distinct from that of calmodulin or other Ca(2+)-binding proteins. RNA-gel blot analysis showed the genes of group I and II were preferentially expressed in anthers at the later developmental stage and in mature pollen. The recombinant proteins produced in Escherichia coli was recognized in immunoblot analysis by the IgE of a Brassica pollen allergic patient, but not by the Ige of a non-allergic patient. The cDNA clones reported here, therefore, represent pollen allergens of Brassica species.

Amino Acid Sequence↗

PubMed1995

Laparoscopic extramucosal myectomy with anterior fundoplication (Dor) for esophageal achalasia using intraoperative manometry.

Laparoscopic extramucosal myectomy with anterior fundoplication according to the Dor technique was performed on a 24-year-old-woman. Intraoperative inflation of a pneumatic balloon made the operative procedures such as extended submucosal dissection quite easy. Intraoperative gastrofiberscopy was useful for confirming that the remaining mucosal layer was not injured after completion of myectomy. Intraoperative manometry confirmed a complete decompression of the high-pressure zone in the lower esophageal sphincter. Complete relief of the symptoms has been recognized for 6 months after operation without any medication. It is considered that these laparoscopic procedures including intraoperative inflation of a pneumatic balloon, gastrofiberscopy, and intraoperative manometry can be used as a standard operation for esophageal achalasia.

Adult↗

PubMed1995

Ca(2+)-dependent Cl- current at the presynaptic terminals of goldfish retinal bipolar cells.

In ON-type bipolar cells dissociated from the goldfish retina, a slowly declining inward current (Itail) was observed after the termination of depolarizing voltage step commands, during which a Ca2+ current was elicited. The properties of Itail were investigated under the whole-cell voltage clamp. Introduction of the membrane permeant Ca2+ chelator, BAPTA/AM, into the cell suppressed Itail, indicating that Itail was activated by the increase of intracellular free Ca2+ concentration ([Ca2+]i). The major component of Itail was identified as the Ca(2+)-dependent Cl- current (ICl(Ca)), since the reversal potential of Itail was almost identical to the Cl- equilibrium potential at various extracellular Cl- concentrations ([Cl-]o). The contribution of the Na+/Ca2+ exchanger current to Itail was very small. ICl(Ca) was partially suppressed by 4-acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic acid (SITS) when it was locally applied to the axon terminal but not to the cell body region, suggesting that Ca(2+)-dependent Cl- channels were localized to the axon terminal. The relationship between the peak amplitude of ICl(Ca) and the amount of charge carried by the Ca2+ current was almost linear at levels less than ca. 50 pC, but became saturated at a higher Ca2+ charge.

Animals↗

PubMed1995

Wortmannin as a unique probe for an intracellular signalling protein, phosphoinositide 3-kinase.

Wortmannin is a fungal metabolite that so far has been shown to act as a selective inhibitor of phosphoinositide 3-kinase. It can therefore be used to investigate the convergence between two major cellular signalling systems: those involving G-protein-coupled receptors and those involving receptor tyrosine kinases. Importantly, wortmannin can enter intact cells, making whole-cell studies of the above signalling pathways possible.

Androstadienes↗