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Biomedical subjects

K Tagawa

Publications and source records attributed to K Tagawa.

At least 37 records · Page 2Linked to original sources
PubMed1998

Enzyme-linked immunosorbent assay for TA-2005-glucuronide in human plasma.

A sensitive enzyme-linked immunosorbent assay (ELISA) for TA-2005-glucuronide, a main metabolite of new adrenergic beta-receptor agonist TA-2005, has been investigated without prior deconjugation. Coupling of the hapten with bovine serum albumin (BSA) or beta-D-galactosidase was carried out by the N-hydroxysuccinimide ester method. An anti-TA-2005-glucuronide antiserum was obtained from guinea pig immunized with the hapten-BSA conjugate. The ELISA was based upon a competitive assay in which the separation of bound from free fraction was performed by the double antibody technique using rabbit anti guinea pig immunoglobulin antibody adsorbed to microtiter plates. A satisfactory standard curve for the ELISA of TA-2005-glucuronide was observed in the range of 30 pg-3 ng ml-1 using 25 microliters of human plasma. Inter-day and intra-assay variations were 7.0-17.5% and 1.0-11.7% respectively. The recoveries of TA-2005-glucuronide spiked to plasma samples were 95.5-120% (inter-assay) and 96.0-123.3% (intra-assay). The cross-reactivities of the prepared antiserum with the related compound of TA-2005-glucuronide were quite low though there was a considerable cross-reaction with TA-2005. However, TA-2005-glucuronide could be easily separated from TA-2005 by a simple pretreatment of the plasma sample with a C18 cartridge column. This method was applied to the determination of TA-2005-glucuronide in human plasma samples for the evaluation of the pharmacokinetics of TA-2005. From the results, it was demonstrated that the ELISA developed was useful for the determination of TA-2005-glucuronide in human plasma and that the method was applicable to pharmacokinetic studies in humans.

Administration, Oral↗
PubMed1998

Novel pattern of Brachyury gene expression in hemichordate embryos.

Together with echinoderms and chordates, hemichordates constitute the third major group of the deuterostomes, which share a number of common developmental features. The Brachyury gene is responsible for the formation of notochord, the most defining feature of chordates. Therefore, isolation and characterization of the hemichordate homolog of Brachyury is key to understand the origin and evolution of chordates. Here we show that the hemichordate Brachyury gene (PfBra) is expressed in two regions of the gastrula and young tornaria larva, the archenteron invagination region and the stomodeum invagination region.

Amino Acid Sequence↗
PubMed1998

The carboxyl-terminal region of the yeast ATPase inhibitor is indispensable for the stability of the protein in mitochondria.

The role of the carboxyl-terminal region of the yeast mitochondrial ATPase inhibitor was investigated. Three progressive C-terminal deletion mutants of the inhibitor were constructed: (i) Ile58-->end; (ii) Ile51-->end; and (iii) Gln43-->end. The truncated inhibitor was detected in extracts of Ile58-->end mutant yeast cells. For the Ile51-->end mutant, the truncated inhibitor was only detected when the cells were grown on medium containing the membrane-permeable metal chelator, o-phenanthroline, which inhibits mitochondrial proteases. The most greatly truncated inhibitor protein, Gln43-->end, was never detected even in the cells grown in the presence of the metal chelator. The rates of ATP synthesis and hydrolysis in the mutant mitochondria containing the Ile51-->end inhibitor were similar to those in wild type control cells, while the Ile51-->end inhibitor protein was degraded in the cells unless they were incubated in the presence of the chelator. These results indicate that the carboxyl-terminal region of the ATPase inhibitor is not involved in the its inhibitory action on the F1Fo-ATPase, but is required for the stable conformation of the protein which is protected against degradation by proteases.

Adenosine Triphosphatases↗
PubMed1998

Characterization of an ascidian maternal T-box gene, As-mT.

The T-box genes encode a novel family of transcriptional factors that seem to play crucial roles in various processes of animal development, in particular, mesoderm formation of chordate embryos. The ascidian egg has been regarded as a typical mosaic egg, in which several types of embryonic cells are specified autonomously dependent on prelocalized maternal factors or determinants. In the present study, we investigated a possible role of a maternal T-box gene (As-mT) of the ascidian Halocynthia roretzi. A cDNA clone we obtained predicted As-mT protein of 891 amino acids with a distinct T-domain, which was divergent from those of other T-box genes. Expression of As-mT was exclusively maternal. Although the transcript became barely detectable by the gastrula stage, no zygotic expression was evident during embryogenesis. The maternal transcript was distributed rather evenly within eggs and early embryos without any special localization. Injection of synthetic As-mT mRNA into fertilized eggs induced retardation of embryogenesis. Although cleavage occurred normally, the initiation of gastrulation was delayed, and delay in the morphogenesis resulted in dumpy larvae. Expression of a muscle-specific actin gene, a notochord-specific Brachyury gene, and an epidermis-specific gene was not detected at the early gastrula stage, all of the three genes being expressed in normal embryos at that stage. However, the expression of these genes as well as a mesenchyme-specific gene and histochemical activity of endoderm-specific alkaline phosphatase were evident by the mid-tailbud stage.

Amino Acid Sequence↗
PubMed1997

Pharmacokinetics and pharmacodynamics of a sustained-release biodegradable pellet containing imidapril, a new angiotensin-converting enzyme inhibitor in spontaneously hypertensive rats.

The pharmacokinetics and pharmacodynamics (PK/PD) of a sustained-release biodegradable pellet containing imidapril, a new angiotensin-converting enzyme (ACE) inhibitor, were investigated in comparison with those of an osmotic pump in male spontaneously hypertensive rats (SHRs). A pellet was prepared from copolymer of DL-lactic acid and glycolic acid by the melt-pressing technique. Imidapril was released in vitro from the pellet at an approximately zero-order rate and the release profile was similar to that of the osmotic pump. Imidapril was administered subcutaneously via a pellet or an osmotic pump implanted under the skin in the back of SHRs. Plasma concentrations of imidaprilat as an active metabolite of imidapril, plasma ACE activity and systolic blood pressure (SBP) were determined periodically. The plasma concentration of imidaprilat during the administration of a pellet was maintained for 4 weeks, and the plasma concentration profile was close to that of the osmotic pump. Both groups of pellet and osmotic pump significantly inhibited plasma ACE activity and reduced SBP for 4 weeks, and these action profiles were similar in both groups. In addition, in vivo release profile of the pellet was close to the in vitro release profile, and the in vivo release profiles of the pellet and the osmotic pump were similar to each other. From these results, it was found that the PK/PD of a biodegradable pellet were close to those of the osmotic pump, and it was shown that the pellet may be a useful system to maintain the plasma concentration of imidaprilat for a long time.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1997

The recently-described ascidian species Molgula tectiformis is a direct developer.

Molgula tectiformis is a new ascidian species recently described by Nishikawa (1991). In Otsuchi Bay, Iwate, Japan, they are easily obtainable from cages for culturing scallops. We report here that M. tectiformis is another example of a direct developer: their embryonic development is lacking the tadpole larva. The fertilized egg is orange and about 150 microns in diameter. At 18 degrees C, the egg cleaves at about 20 min intervals and gastrulation occurs about 5 hr after fertilization. In contrast to conventionally-developing ascidians, M. tectiformis does not form a tadpole larva. Immediately before hatching, three stolons or ampullae begin to extend from the tailless embryo. After hatching the stolons mediate the attachment of the juvenile body to the substratum. Histochemistry for tissue-specific enzyme activity did not detect muscle-specific acetyl-cholinesterase, endoderm-specific alkaline phosphatase, and pigment cell-specific tyrosinase. In addition, in situ hybridization could not prove the presence of muscle actin gene transcripts in the embryo. These results suggest that these larval tissues do not differentiate in M. tectiformis embryos. Because M. tectiformis is common and gravid year-around in Otsuchi Bay, this direct developer provides the opportunity for further analysis of molecular changes during evolution that cause an alternative mode of development.

Acetylcholinesterase↗
PubMed1996

Mutation of potential N-linked glycosylation sites in the Alzheimer's disease amyloid precursor protein (APP).

In order to study the mechanism of intracellular sorting and processing of the Alzheimer's disease amyloid precursor protein (APP), we deleted two potential N-linked glycosylation sites of APP by site-directed mutagenesis. Substitution of alanines for the critical asparagine residues Asn467 and Asn496 was performed. Wild-type and mutant APPs were expressed in COS-1 cells by cDNA transfection and the expressed of the protein and secretion of N-terminal large fragment was observed. The initial secretion of the mutant APP appeared to be slow compared with wild-type. In addition, we found that a distinct APP fragment, the cytosolic form, is transiently increased in the cytosol fraction of COS-1 cells. These results suggest that aberrant processing occurs following the expression of a mutant APP with Ala substituted for Asn, and that glycosylation may modulate the intracellular sorting of APP.

Alzheimer Disease↗
PubMed1996

Effects of active and passive recoveries on splitting of the inorganic phosphate peak determined by 31P-nuclear magnetic resonance spectroscopy.

Six male long-distance runners performed knee flexion exercises in a 2.1 T superconducting magnet. 31P MRS was used to investigate the splitting pattern of the inorganic phosphate (Pi) peak during active and passive recovery. During exercise splitting of the Pi peak into two was observed (high and low pH) and after exercise the manner in which the Pi peak disappeared was different in passive and active recoveries. During passive recovery, in which exercise was not performed at all, the high-pH Pi peak disappeared more rapidly than the low-pH Pi peak. The low-pH Pi peak remained at a similar acidified chemical shift as during exercise, and then gradually disappeared during passive recovery. Conversely, during active recovery in which unloaded exercise was followed, the high-pH Pi peak was reduced, but remained, whereas the low-pH Pi peak returned very quickly to the pre-exercise level and then disappeared. Teh recovery rate of the low pH during active recovery (0.095 +/- 0.019 pH units/min) was significantly faster than that during passive recovery (0.014 +/- 0.019 pH units/min) (p < 0.01). The slow disappearance of the low pH Pi peak during passive recovery can be explained by the halting of glycogenolysis and an insufficient oxygen supply to resting glycolytic fibers, whereas the quick disappearance observed with active recovery would have been due to elevated sufficient oxygen supply and efficient removal of lactate as a result of the maintained blood flow. Oxy-myoglobin and hemoglobin was also measured with near infrared spectroscopy.

Adult↗
PubMed1996

An intrinsic ATPase inhibitor binds near the active site of yeast mitochondrial F1-ATPase.

An ATPase inhibitor and its stabilizing factor, the 9K protein, are regulatory factors of F1F0-ATPase. The binding sites for these factors on F1 were examined using the zero length cross-linkers, N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline, and 1-ethyl-3-[3-dimethylamino)propyl]carbodiimide. The cross-linked products were analyzed by immunoblotting after SDS-polyacrylamide gel electrophoresis. The inhibitor and the 9K protein cross-linked to the alpha and beta subunits of F1, indicating that they interacted with both subunits. Peptide mapping and amino acid sequence analysis of the cross-linked products after weak acid hydrolysis showed that the inhibitor cross-linked to the Pro334-Asp363 region of the beta subunit. Amino acid sequence analysis of the cross-linked peptide showed that the inhibitor binds to Asp363 of the beta subunit. As this region contains the amino acid residues, including Tyr359, that are modified by nucleotide analogs and form the active site, the inhibitor probably binds to the catalytic site of F1.

Amino Acid Sequence↗
PubMed1996

[Antituberculous drug-resistance among homeless peoples].

We studied on the prevalence of drug-resistance among 65 homeless cases who were admitted and treated for active tuberculosis at the Nakano National Chest Hospital during the period from 1990 to 1992 and at the International Medical Center of Japan during the period from 1993 to 1994. Resistance to one or more first line antituberculous drug were revealed in 14 cases out of 65 (21.5%) in initially treated cases 6 out of 43, and in retreated cases 8 out of 22. The prevalence of drug resistance in this study was significantly higher compared with 2 out of 39 cases (5.1%) in our previous report during the period from 1986 to 1988. In these drug-resistant cases, multidrug-resistant cases, namely, resistant to at least 2 drugs including both INH and RFP were founded in 6 cases (9.2%). Compared with drug-sensitive cases, the negative convertion rate of bacilli was lower and the number of defalters was significantly larger. It was suggested that higher prevalence of drug-resistance and defalting from the adequate treatment in homeless cases of tuberculosis possibly makes the prognosis of drug-resistant tuberculosis worse and treatment of such cases more difficult.

Adult↗
PubMed1995

Muscle-specific calpain, p94, responsible for limb girdle muscular dystrophy type 2A, associates with connectin through IS2, a p94-specific sequence.

p94, a muscle-specific member of calpain family, is unique in that it undergoes rapid and exhaustive autolysis with a half-life of less than 1 h resulting in its disappearance from muscle. Recently, p94 was shown to be responsible for limb girdle muscular dystrophy type 2A. To elucidate the muscular proteolytic system mediated by p94 and to solve the mystery of its unusually rapid autolysis, we searched for p94-binding proteins by the two-hybrid system. Although calpain small subunit plays a crucial role for regulation of ubiquitous calpains, it did not associate with p94. After a screening of skeletal muscle library, connectin (or titin), a gigantic filamentous protein spanning the M- to Z-lines of muscle sarcomere, was found to bind to p94 through a p94-specific region, IS2. The connectin-insoluble fraction of washed myofibrils contained full-length intact p94, suggesting that connectin regulates p94 activity.

Amino Acid Sequence↗
PubMed1995

Secretion of Alzheimer beta/A4 protein (1-40) and intracellular retention of beta/A4 protein (1-42) in transfected COS cells.

The amyloid beta/A4 protein (beta/A4) of Alzheimer disease is heterogeneous. A beta 1-40 (Asp1 to Val40) is rather soluble, whereas A beta 1-42 (Asp1 to Ala42) is more insoluble and can be the seed of deposition of A beta 1-40. Although beta/A4 itself could not be expressed transiently in COS cells by cDNA transfection, it was expressed after directly adding a signal sequence to its N-terminal end. The expressed A beta 1-40 was secreted, whereas A beta 1-42 was hardly secreted. A beta 1-40 secretion was not inhibited by metabolic inhibitors such as brefeldin A. The normally produced A beta 1-40 could not be retained intracellularly, whereas the abnormally generated A beta 1-42 might be accumulated intracellularly, resulting in cellular toxicity.

Amino Acid Sequence↗
PubMed1995

Ca2+ release from mitochondria induces cytosolic enzyme leakage in anoxic liver.

The mechanisms of elevation of cytosolic Ca2+ concentration during anoxia causing cytosolic enzyme leakage were studied in perfused rat liver. Before anoxia the Ca2+ contents in mitochondria of perfused rat liver were varied by addition of noradrenaline and glucagon, lowering Ca2+ concentration in the perfusion medium, and addition of Ca2+ channel blocker, either singly or in combination. The amount of cytosolic enzyme leakage during anoxic perfusion positively correlated with the mitochondrial Ca2+ content just before anoxia and also with Ca2+ release from mitochondria during anoxia. However, the amount of cytosolic enzyme leakage during anoxic perfusion did not correlate with the Ca2+ concentration in the perfusion medium and microsomal Ca2+ content. These data support the hypothesis that in anoxic liver, the cytosolic Ca2+ concentration is elevated to a pathological level mainly by Ca2+ release from mitochondria, causing the cytosolic enzyme leakage.

Animals↗
PubMed1995

Onset of diabetes with high titer anti-GAD antibody after IFN therapy for chronic hepatitis.

A case of hyperglycemia induced by the injection of interferon-alpha was experienced in our hospital. This patient showed a sustained high titer of anti-GAD antibody after the onset of diabetes, suggesting that the involvement of immunological disturbance by IFN induces the onset of the disease. However, the susceptibility and the response of the immune system differs from patient to patient, and only limited destruction of beta-cells in the islet of Langerhans and normalization of glucose tolerance by CSII was induced in this patient.

Antiviral Agents↗
PubMed1995

Cleavage of bovine mitochondrial ATPase inhibitor with endopeptidases, and binding of the resulting peptides to the interface between the alpha- and beta-subunits of F1ATPase.

Mitochondrial ATPase inhibitor binds to F1ATPase, forming an equimolar complex with the enzyme, and the binding site has been reported to be located in the beta-subunit [Klein, G. et al. (1980) Biochemistry 19, 2919-2925] or at the interface between the alpha- and beta-subunits of the enzyme [Mimura, H. et al. (1993) J. Biochem. 113, 350-354]. In the present study, bovine ATPase inhibitor as well as three peptide fragments of the inhibitor, Gly1-Asn51, Glu52-Asp84, and Lys46-Asp84, were used to examine the features of the binding of the inhibitor and F1ATPase. Only the amino terminal fragment, Gly1-Asn51, exhibited a similar level of inhibitory activity to that of the native ATPase inhibitor. Although the other two carboxyl terminal side fragments did not exhibit any inhibitory activity, they interfered with the action of the intact ATPase inhibitor when they were pre-loaded to F1ATPase. Since the two carboxyl fragments did not interfere with the inhibitory action of the amino fragment, it is inferred that the inhibitor interacts with F1ATPase at its carboxyl terminal region prior to binding at the amino terminal region of the enzyme. Cross-linking experiments revealed that ATPase inhibitor bound to the alpha- and beta-subunits of F1ATPase, and that the amino terminal peptide preferentially bound to the alpha-subunit and the carboxyl terminal peptides to the beta-subunit.

Adenosine Triphosphatases↗
PubMed1995

Proliferating trichilemmal tumor on the dorsum of the hand.

A patient with a proliferating trichilemmal tumor on the dorsum of a hand is described. A surgical excision was performed, and the skin defect was covered with a distally based posterior interosseous island flap. In the operation, an iron fragment was found beneath the mass, and this was thought to have triggered development of the tumor.

Aged↗