Search PubMed⌕ Search

Biomedical subjects

T Adachi

Publications and source records attributed to T Adachi.

At least 415 records · Page 23Linked to original sources
PubMed1991

Molecular cloning of the gene for indolepyruvate decarboxylase from Enterobacter cloacae.

Although indole-3-acetic acid (IAA) is a well-known plant hormone, the main IAA biosynthetic pathway from L-tryptophan (Trp) via indole-3-pyruvic acid (IPyA) has yet to be elucidated. Previous studies have suggested that IAA is produced by Enterobacter cloacae isolated from the rhizosphere of cucumbers and its biosynthetic pathway may possibly be the same as that in plants. To elucidate this pathway, the IAA biosynthetic gene was isolated from a genomic library of E. cloacae by assaying for the ability to convert Trp to IAA. DNA sequence analysis showed that this gene codes for only one enzyme and its predicted protein sequence has extensive homology with pyruvate decarboxylase in yeast and Zymomonas mobilis. Cell-free extracts prepared from Escherichia coli harboring this gene could convert IPyA to indole-3-acetaldehyde (IAAld). These results clearly show that this pathway is mediated only by indolepyruvate decarboxylase, which catalyzes the conversion of IPyA to IAAld.

Amino Acid Sequence↗
PubMed1991

Repression of the cell wall protein gene operon in Bacillus brevis 47 by magnesium and calcium ions.

Transcription from P2, one of the major promoters of the cell wall protein gene operon of Bacillus brevis 47, was markedly enhanced at the early stationary phase of growth. MgCl2, when added at 1 to 5 mM to the medium, inhibited this enhancement of transcription as well as shedding of the cell wall protein layers from the cell surface. MgSO4 or CaCl2 showed an effect similar to that of MgCl2. The possible coordination of the cell wall structure with regulation of the cell wall protein genes is discussed.

Bacillus↗
PubMed1991

Myocardial infarct size-limiting effect of ischemic preconditioning was not attenuated by oxygen free-radical scavengers in the rabbit.

BACKGROUND: The limiting effect of ischemic preconditioning on infarct size has been reported in canine hearts, which contain considerable amounts of xanthine oxidase, a free radical-producing enzyme. Furthermore, a recent study suggested that free radicals generated during preconditioning may contribute to the cardioprotective effect of preconditioning. The present study examined 1) whether preconditioning limits infarct size in rabbits, which, like humans, lack myocardial xanthine oxidase and 2) whether the cardioprotective effect of PC is mediated by free radicals. METHODS AND RESULTS: A branch of the circumflex coronary artery in rabbits was occluded for 30 minutes and then reperfused for 72 hours. Myocardial infarct size and area at risk were determined by histology and fluorescent particles, respectively. Five groups were studied: an untreated control group, a preconditioned group (PC group), a high-dose superoxide dismutase (SOD)-treated preconditioned group (high-dose SOD-PC group), a low-dose SOD-treated preconditioned group (low-dose SOD-PC group), and a SOD-plus-catalase-treated preconditioned group (SOD/CAT-PC group). Preconditioning was performed with four episodes of 5 minutes of ischemia and 5 minutes of reperfusion. The free radical scavengers (30,000 units/kg SOD for high-dose SOD-PC group, 15,000 units/kg SOD for low-dose SOD-PC group, and 30,000 units/kg SOD plus 55,000 units/kg catalase for SOD/CAT-PC group) were infused intravenously over 60 minutes starting 20 minutes before preconditioning. Infarct size as the percentage of area at risk was 45.1 +/- 3.5% (mean +/- SEM) in the control group (n = 11), 13.3 +/- 3.0% in the PC group (n = 12), 9.7 +/- 1.8% in the high-dose SOD-PC group (n = 8), 11.9 +/- 2.2% in the low-dose SOD-PC group (n = 6), and 9.6 +/- 2.3% in the SOD/CAT-PC group (n = 6) (p less than 0.05 versus control for the last four values). The differences in infarct size as the percent of area at risk among the PC, high-dose SOD-PC, low-dose SOD-PC, and SOD/CAT-PC groups were not significant. CONCLUSION: Ischemic preconditioning delays ischemic myocardial necrosis regardless of myocardial xanthine oxidase content. Free radicals are unlikely to have a major role in the mechanism of the preconditioning in rabbits.

Animals↗
PubMed1991

Enzyme immunoassay for the drug of anti-ulcer using avidin-biotin system.

We have developed a competitive enzyme immunoassay for a drug, which was a newly synthesized anti-ulcer agent, using an enzyme immunoassay. The polyclonal anti-drug antibody coupled to biotin, peroxidase labeled drug derivatives as a tracer, and a small column of Sepharose 4B covalently bound to avidin were used in the assay. This assay is simple and rapid, and the sensitivity and the measuring range can be controlled by the flow rate of the substrate solution. The correlation between serum drug concentrations (0.1-10 micrograms/ml) measured by gas chromatography and this assay was good (r = 0.991). This principle for the assay is very practical and applicable to the enzyme immunoassay for small and large molecules.

Administration, Oral↗
PubMed1991

Analysis by deletion and site-directed mutagenesis of promoters of the cell wall protein gene operon in Bacillus brevis 47.

The cell wall protein gene operon of Bacillus brevis 47 has multiple and tandem promoters. The precise locations of the two major promoters (P2 and P3) of the operon were determined by deletion analysis. This together with results of oligonucleotide-directed mutagenesis of the promoter regions confirmed that the -35 and -10 sequences of the two promoters proposed previously are essential for their promoter activity. A G + C-rich sequence upstream of the -35 region of P2 and an A-rich sequence upstream of the -35 region of P3 facilitate the transcription from P2 and P3, respectively.

Bacillus↗
PubMed1991

Establishment and characterization of a bi-phenotypic leukemic cell line, NALM-19, from a patient with acute leukemia.

Based on the immunophenotypic and genotypic findings, this acute leukemia cell line, designated NALM-19, is unique in that a partial expression of both B-cell and myeloid cell features are present in this single clonal leukemic cell population. It is noteworthy that two "normal" EB virus-transformed B cell lines, B239 and B240, (paired with NALM-19) were established from the same leukemic blood.

Acute Disease↗
PubMed1991

Two t(9;22) leukemia cell lines (NALM-24 and NALM-25) with bi-phenotypic characteristics and an EBV-positive B-cell non-leukemia cell line (B262) established from a patient with acute lymphoblastic leukemia.

Based on the immunophenotypic, cytogenetic and genotypic findings, two unique leukemia cell lines, NALM-24 and NALM-25, and an EBV-transformed "normal" B-lymphoblastoid cell line (B262) from a patient with ALL were established and characterized. NALM-24 and NALM-25 are unique in that expression of both show B cell and myeloid cell features with the t(9;22) chromosome in single clonal leukemic cell populations.

Adult↗
PubMed1991

Measurement of free form of insulin-like growth factor I in human plasma.

A method to measure free form of insulin-like growth factor I (IGF-I) in human plasma using octadecylsilyl silica (Sep-Pak C18) cartridge has been developed. IGF-I was adsorbed by Sep-Pak C18 cartridge and eluted with 75% ethanol--0.01 M HCl. Labeled and non-labeled IGF-I were recovered in yields 92.5 +/- 2.1% (Mean +/- SEM) and 94.4 +/- 6.3% after adsorption to and elution from the Sep-Pak, respectively. When EDTA plasma was applied to the Sep-Pak, less than 5% of total IGF-I was recovered in the eluate. However, when acid-ethanol extracted plasma was applied to the Sep-Pak, IGF-I was recovered in yields greater than 75% of total IGF-I. When the Sep-Pak eluate was gel filtered, 88.4 +/- 4.0% of immunoreactive IGF-I eluted in the same fraction as synthetic IGF-I did, but the fraction passed through the Sep-Pak was observed as a high molecular weight form (bound form) of IGF-I. These data indicate that this Sep-Pak method does not extract all of the IGF-I in plasma, but extracts mainly the free form IGF-I. Using this method, IGF-I values of free form (fIGF-I) in EDTA plasma were measured. The fIGF-I values in normal adults, patients with acromegaly, and patients with growth hormone (GH)-deficiency were 2.4 +/- 0.1, 13.8 +/- 1.6, and 1.1 +/- 0.1 ng/ml, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Acromegaly↗
PubMed1990

[Purification and characterization of insulin-like growth factor binding proteins (IGF-BP) in amniotic fluid--existence of a 160K IGF-BP].

Human amniotic fluid has been reported to contain 28-34K insulin-like growth factor (IGF) binding protein (32K-AFBP). The existence of 160K IGF-binding protein (160K-AFBP) in amniotic fluid was also demonstrated by affinity labeling studies. In this paper we describe procedures for purification of 160K-AFBP as well as 32K-AFBP from pre-term amniotic fluid and characterize these two binding proteins. IGF binding proteins were purified from batches of 500ml of pre-term amniotic fluid using ammonium sulphate precipitation, anion-exchange chromatography (Q-Sepharose) and Sephacryl S-200 HR chromatography. IGF binding activity during purification was quantitated by incubation with 125I-IGF-I and dextran-coated charcoal separation. The total recovery and purification of binding protein were 38% and 81.5-fold, respectively. The three major binding activities were eluted in fractions corresponding to a relative molecular mass of 160K, 60K and 30K when Q-Sepharose purified AFBPs were chromatographed on Sephacryl S-200 HR at neutral pH. HPLC of purified 160K binding activity on size exclusion column yielded a single peak of absorbance at 280nm, corresponding to an apparent molecular weight of 160K with three predominant peaks of binding to 125I-IGF-I, corresponding to molecular weights of 160K, 79K and 32K, respectively. On the other hand, purified 30K binding activity on HPLC yielded a single peak of absorbance at 280nm, corresponding to an apparent molecular weight of 32K coincident with a peak of binding to 125I-IGF-I. SDS-PAGE of HPLC purified 160K-AFBP in the presence of mercaptoethanol revealed eight bands by Coomassie Blue staining, five major bands corresponding to 160K, 78K, 69K, 54K, and 51K and three weaker bands corresponding to 45K, 36K, and 28K. The HPLC purified 32K-AFBP showed a single band of a molecular mass estimate of 32K on SDS-PAGE. These results indicate that human amniotic fluid contains at least two distinct IGF-binding proteins, and the structure of 160K-AFBP is similar to those of 150K binding protein in the circulation.

Amniotic Fluid↗
PubMed1990

Responses of regional cerebral blood flow following focal electrical stimulation of the nucleus basalis of Meynert and the medial septum using the [14C]iodoantipyrine method in rats.

The effects of focal electrical stimulation of the nucleus basalis of Meynert (NBM) and the medial septum (MS) on regional cerebral blood flow (rCBF) of the 14 brain regions were examined in halothane-anesthetized rats using the [14C]iodoantipyrine ([14C]IAP) method. The stimulation of the unilateral NBM (with parameters of 200 microA, 0.5 ms, 50 Hz for 60 s) produced significant increases in frontal, parietal and occipital cortical blood flows in the hemisphere ipsilateral to the stimulated NBM; no rCBFs in all other brain regions examined were influenced by the stimulation. The stimulation of the MS produced significant increases in bilateral hippocampal rCBFs, but rCBFs in other brain regions were not influenced by the stimulation. In summary, the response of increase in rCBF following focal electrical stimulation of the NBM or MS is restricted to regions that receive cholinergic nerve projections from the NBM or MS.

Animals↗
PubMed1990

Stimulation of the nucleus basalis of Meynert and substantia innominata produces widespread increases in cerebral blood flow in the frontal, parietal and occipital cortices.

The effect of a focal stimulation of the magnocellular nucleus of the basal forebrain at two different areas, the nucleus basalis of Meynert (NBM) and the substantia innominata (SI), on local cerebral blood flow (CBF) in the frontal, parietal and occipital cortices was examined in urethane-anesthetized rats. The stimulation, either electrically or chemically, of both the NBM and SI produced significant CBF increase in all these 3 cortices ipsilateral to the stimulation site. This fact suggests that activation of neurons originating in the NBM and SI produces widespread increases in local CBF in the ipsilateral cerebral cortex.

Animals↗
PubMed1990

Genomic organization and physical mapping of the transfer RNA genes in Escherichia coli K12.

By using a set of 476 ordered DNA clones (in lambda phage vector) that covers the entire chromosome of Escherichia coli K12, we have made an exhaustive survey of tRNA genes in the E. coli genome. Ultraviolet-irradiated bacteria were separately infected with each of the 476 clones and the RNA molecules produced upon infection were labeled with 32P. The labeled tRNAs were separated by gel electrophoresis and then characterized by fingerprinting analysis. Fifty-nine of the 476 clones produced tRNAs, including adjacent overlapping ones that share the same tRNA genes. The products of all the previously mapped tRNA genes (about 60, to date) were detected according to their expected positions, and 19 more tRNA genes were newly elucidated. These new tRNA genes were identified by sequencing the DNA from relevant regions of the clones; the DNA sequences were scanned for the stretches that could be folded into the familiar cloverleaf structure and the transcription units were deduced by predicting the promoters and terminators. The total complement of the tRNA genes in E. coli K12 was 78 for 45 tRNA (or 41 anticodon) species, distributed in 40 different transcription units throughout the chromosome. In addition, a gene for selenocysteine tRNA was detected by hybridization and mapped to a specific DNA segment. A comprehensive tRNA gene map of E. coli was constructed, including the selenocysteine tRNA gene. All the tRNA genes encode the 3' CCA, and in several cases the terminal 19 nucleotides (including the 3' CCA) of a tRNA gene is repeated several times. Finally, in the present study the sites for a long inversion (approx. 800 x 10(3) base-pairs, around the oriC region) in Kohara's library was determined to be within the 23 S-5 S regions in rrnD and rrnE, revealing the exchange of combinations of spacer and distal tRNA genes between these two ribosomal RNA operons.

Base Sequence↗
PubMed1990

Molecular cloning of the Bombyx mori prothoracicotropic hormone.

Prothoracicotropic hormone (PTTH), a brain secretory polypeptide of insects, stimulates the prothoracic glands to produce and release ecdysone, the steroid essential to insect development. The complementary DNAs encoding PTTH of the silkmoth Bombyx mori were cloned and characterized, and the complete amino acid sequence was deduced. The data indicated that PTTH is first synthesized as a 224-amino acid polypeptide precursor containing three proteolytic cleavage signals. The carboxyl-terminal component (109 amino acids) that follows the last cleavage signal represents one PTTH subunit. Two PTTH subunits are linked together by disulfide bonds, before or after cleavage from prepro-PTTH, to form a homodimeric PTTH. When introduced into Escherichia coli cells, the complementary DNA directed the expression of an active substance that was functionally indistinguishable from natural PTTH. In situ hybridization showed the localization of the prepro-PTTH mRNA to two dorsolateral neurosecretory cells of the Bombyx brain.

Amino Acid Sequence↗
PubMed1990

A one-step enzyme immunoassay for human manganese superoxide dismutase with monoclonal antibodies.

A one-step enzyme immunoassay for the determination of manganese superoxide dismutase in serum has been developed with two kinds of monoclonal antibodies. Proposed method had high sensitivity (assay range, 0.4-200 ng/ml), good recovery (recovery percentage, 102.9-106.2%) and reproducibility (intraassay, C.V. = 1.87-3.66%; interassay, C.V. = 3.03-10.4%). From these results, it is possible to apply this method to routine clinical analysis and biochemical research with various purposes.

Animals↗
PubMed1990

Cutaneous stimulation regulates blood flow in cerebral cortex in anesthetized rats.

The effect of noxious or innocuous mechanical stimulation of cutaneous areas (face, forelimb and paw, back, hindlimb and paw) on cerebral blood flow in cortex was examined with laser Doppler flowmetry in anesthetized rats. Pinching of the face, forepaw and hindpaw for 15 s produced significant increases of systemic blood pressure and of cortical blood flow, whereas pinching of the back or brushing of any cutaneous area produced no significant changes in either parameter. Following spinal transection at the first thoracic level, the blood pressure response to forepaw pinching was suppressed, whereas the increase in cortical blood flow still took place. Thus the results suggest that the increase in cortical blood flow following cutaneous noxious stimulation is, in part at least, independent of changes in blood pressure and of any concomitant vasodilatation.

Anesthesia↗
PubMed1990

Does verapamil limit myocardial infarct size in a heart deficient in xanthine oxidase?

1. The delay of ischaemic myocardial necrosis by verapamil has been reported in the dog heart, which contains a high level of xanthine oxidase, a potential source of cytotoxic free radicals. To test whether the retardation of ischaemic myocyte death by verapamil is not an isolated phenomenon in the xanthine oxidase rich heart, we assessed the effect of verapamil in the rabbit heart, which lacks xanthine oxidase. 2. Verapamil (200 micrograms/kg, i.v. bolus plus 40 micrograms/kg per min) was administered in a group of rabbits (n = 5) to test the haemodynamic response to this agent. The heart rate, blood pressure and left ventricular dp/dt max were reduced by 11, 25 and 57%, respectively, and the plasma concentration of verapamil was maintained at 300-400 ng/mL during the infusion. 3. In other groups of rabbits, the effect of the same dosage of verapamil on the size of myocardial infarct after 20 or 30 min ischaemia and 72 h reperfusion was examined. The verapamil was administered for 45 min, starting 15 min prior to ischaemia. The percentage of area at risk infarcted (%I/AAR) was 15.2 +/- 3.9% in the 20 min ischaemia control group and 15.4 +/- 4.5% in the 20 min ischaemia verapamil group, 49.1 +/- 3.4% in the 30 min ischaemia control group and 41.2 +/- 3.3% in the 30 min ischaemia verapamil group. The %I/AAR was significantly smaller in the 20 min ischaemia control groups and 15.4 +/- 4.5% in the 20 min ischaemia there was no difference in %I/AAR between the control and verapamil treated animals in either the 20 or the 30 min ischaemia groups. 4. These results suggest that verapamil does not delay the transition from reversible to irreversible myocardial injury during coronary occlusion in the rabbit, which like the human, lacks myocardial xanthine oxidase.

Animals↗