Search PubMed⌕ Search

Biomedical subjects

T Takagi

Publications and source records attributed to T Takagi.

At least 631 records · Page 35Linked to original sources
PubMed1990

HPLC resolution of diacylglycerol moieties of natural triacylglycerols on a chiral phase consisting of bonded (R)-(+)-1-(1-naphthyl)ethylamine.

Chiral phase high performance liquid chromatographic resolution of sn-1,2(2,3)- and X-1,3-diacylglycerols generated by partial Grignard degradation from natural triacylglycerols was carried out using a chiral column (25 cm x 4.6 mm i.d.) containing (R)-(+)-1-(1-napthyl)ethylamine polymer chemically bonded to 300A wide pore spherical silica (5 microns particles). The diacylglycerols were chromatographed as 3,5-dinitrophenyl-urethanes and detected at 226 or 254 nm UV. By an isocratic elution with n-hexane- 1,2-dichloroethane-ethanol 40:10:1 (v/v/v) as the mobile phase, the sn-1,2(2,3)-diacylglycerols from corn, linseed, and menhaden oils were resolved into two clearly distinguishable enantiomer groups, although some peak overlappings between the enantiomers were observed in the linseed and menhaden oil diacylglycerols. In addition to the excellent enantiomer resolution, each enantiomer and the X-1,3-isomers were partially resolved into several peaks, which could be tentatively identified on the basis of equivalent carbon number. It is concluded that chiral phase high performance liquid chromatography can be utilized for effective resolution, identification, and quantitation of enantiomeric diacylglycerols from complex natural mixtures.

Chromatography, High Pressure Liquid↗
PubMed1990

[Prominent lymphadenopathy and double Ph1 chromosomes as initial and recurrent manifestations of chronic myelogenous leukemia in blast crisis: report of a case and review of the literature].

A 60-year-old woman was admitted because of fatigue. Physical examination revealed prominent peripheral lymphadenopathy, marked tonsillar swelling and hepatosplenomegaly. The leukocyte count was 68,900/microliters with 75% lymphoid blasts and 5% basophils. The karyotype of the blood cells was 46, XX, Ph1/47, XX, Ph1, +Ph1. The diagnosis of CML in blast crisis was made. After chemotherapy using adriamycin, cyclophosphamide, vincristine, and prednisolone (CHOP), lymphadenopathy and splenomegaly reduced and lymphoid blasts disappeared from the blood and bone marrow. At that time only single Ph1 (46, XX, Ph1) clone was detected in her bone marrow. Four months later, hematological relapse accompanied by lymphadenopathy occurred and DNA analysis of the blasts showed the rearrangement of bcr gene. The simultaneous chromosomal analyses of the blood, bone marrow and lymph node revealed that almost all cells examined had the karyotype "47, XX, Ph1, + Ph1". In spite of repeated chemotherapy the patient did not improve and died. This case suggests a relationship between lymphadenopathy and double Ph1 chromosomes in CML.

Blast Crisis↗
PubMed1990

Evolution and progression in malignant lymphoma of Waldeyer's ring: histopathological and immunohistochemical studies of three cases of total tonsillectomy.

Histopathological and immunohistochemical studies were performed in three patients with malignant lymphoma of Waldeyer's ring (ML-WR) who underwent total tonsillectomies. Residual reactive follicles mixed with neoplastic follicles were present beneath the surface epithelium of the crypts at the base of the tonsils. The neoplastic follicles were growing expansively and fusing with each other until finally, the process resulted in a diffuse proliferation pattern. Both of the tumor and follicular center cells (FCCs) in the reactive follicles were positive for LN-1; accordingly, the ML-WR tumor cells were considered to originate from FCCs. Anti-S-100 positive follicular dendritic cells (FDCs) were much scarcer in the neoplastic follicles of the tonsils than in the neoplastic follicles of the lymph nodes. FDCs may have a role to play in regulating the proliferation pattern of tumor cells in ML-WR.

Adult↗
PubMed1990

[Effect of low-dose aspirin therapy on utero-placental blood flow and malondialdehyde (MDA) as an indicator of its therapeutic effect].

Pregnancy-induced hypertension (PIH) and preeclampsia develop when an imbalance occurs between prostacyclin (PGI2) and thromboxane A2 (TXA2) production. PGI2 promotes vasodilation and decreases platelet adhesiveness, while TXA2 acts as a vasoconstrictor and enhances platelet aggregation and adhesion to vascular walls. The PGI2/TXA2 ratio appears to be important in pregnancy and the development of the functioning uteroplacental unit. Recently, antiplatelet treatment such as low-dose aspirin therapy has been effective in preventing the development of PIH and preeclampsia. TXA2 breaks down spontaneously into a stable substance, TXB2, which is inactive. Another stable, inactive metabolite, malondialdehyde (MDA), is formed via the same pathway. TXB2 and MDA are produced in approximately equimolar quantities. We studied the effects of a low-dose aspirin prescription. Production of MDA was remarkably suppressed during the low-dose aspirin therapy. Furthermore, pulsed doppler ultrasound assessment of blood flow was performed in the fetal descending aorta, umbilical artery and uterine artery of the low-dose aspirin therapy patients. Doppler abnormalities were improved during the therapy. It is concluded that low-dose aspirin improves the uteroplacental blood flow assessed by pulse doppler waveform and that determination of MDA is useful as an indicator of platelet thromboxane synthesis.

Adult↗
PubMed1990

[Group specific component protein (Gc) in patients with acute hepatic necrosis].

We studied the clinical significance of serum Gc levels in the sera of patients with acute hepatic necrosis. Gc concentration were measured using an EIA in double sandwich technique with purified Gc as standard. Mean levels of serum Gc were 6.0 +/- 7.4 mg/dl in fulminant hepatitis, 20.8 +/- 13.6 mg/dl in acute hepatitis and 39.4 +/- 13.8 mg/dl in normal subjects respectively. There was slight correlation between Gc and PTT (P less than 0.05). In the observation of sequential study in patients with fulminant hepatitis, serum Gc levels of live cases elevated but those of dead cases slightly elevated, thereafter decreased. These results suggested that serum Gc levels was the useful marker as a grade of liver cell damage and a parameter of regeneration in liver cells.

Acute Disease↗
PubMed1990

[Experience with shunting operation using a pressure-adjustable valve].

Ten patients, 8 with hydrocephalus and 2 with a subdural fluid collection, were operated using a pressure-adjustable shunt system (SOPHY). The valve-pressure of this shunt device can be adjusted percutaneously by means of a specially designed magnet. In the postoperative course, the valve-pressure was reset in 7 patients. In four patients, valve-resetting was necessitated because of inappropriate valve pressure. In the others, resetting was performed in order to confirm shunt-independence. Especially, in the case with disproportional large communicating fourth ventricle, we could adjust valve-pressure three times without surgical procedure. Although the number of cases in this study is small, this shunt device seems to be efficient in treating both the disorders of CSF circulation and subdural fluid collections. However, this device must make an artifact in the MR imaging because of its small pieces of magnet. So we recommend the device is placed on the chest if the follow-up MR imaging is necessitated. And as it is larger than other kinds of shunt devices, it might cause the necrosis of the skin on the device, especially in the newborn. But we have never seen the necrotic change of the skin since our first operation using it.

Adolescent↗
PubMed1990

[Transient monocytic skin infiltrate during preleukemic phase of acute myelomonocytic leukemia].

An acute myelomonocytic leukemia presenting transient skin rash during preleukemic phase was described. Following four years of unexplained leukopenia, a generalized exanthema developed and subsequently regressed spontaneously. The skin biopsy and immunohistochemistry revealed monocytic infiltration into the dermis. Twenty-eight months later, the patient became leukemic and died. The skin lesions, however, did not occur after leukemic transformation. Probably transient monocytic skin infiltrate was a symptom of preleukemia, a stem cell neoplasm manifested by functionally abnormal maturation.

Aged↗
PubMed1990

[Assessment of primary varicose veins with plethysmographic techniques].

Venous hemodynamics were evaluated by simultaneous strain gauge- and photo-plethysmographic techniques in 40 normal limbs (normal group), 74 limbs with primary varicose veins (varicosis group) and 28 limbs with postthrombotic syndrome (thrombosis group). Furthermore, the venous function of 52 limbs with primary varicose veins was assessed before and after surgical treatment of varicose veins. The mean 1/2-refilling time in varicosis and thrombosis group was significantly shorter than that in normal group. With application of tourniquets, limbs in varicosis group showed improvement in 1/2-refilling time. Varicosis group showed a significantly higher value in expelled volume during exercise than thrombosis group, and no significant difference compared with normal group. With tourniquets, the value in varicosis group was higher than that in normal group. From these results, the pathogenesis of primary varicose veins might be characterized as a high degree of venous congestion of the leg and valvular incompetence of the superficial vein system. Postoperative recording showed the improvement in venous function. However, in early stage after the operation, all parameters were lower than those in normal group. These values normalized 3 months after surgery.

Hemodynamics↗
PubMed1989

Amino acid sequence of the dimeric hemoglobin (Hb I) from the deep-sea cold-seep clam Calyptogena soyoae and the phylogenetic relationship with other molluscan globins.

The deep-sea cold-seep clam Calyptogena soyoae has two homodimeric hemoglobins (Hbs I and II) in erythrocytes. The complete amino acid sequence of Hb I has been determined. It is composed of 144 amino acid residues, has a high content of hydrophobic residues, and a calculated molecular weight of 16,350 including a heme group. The sequence of Calyptogena Hb I showed high homology (42% identity) with that of Calyptogena Hb II (Suzuki, T., Takagi T. and Ohta, S. (1989) Biochem. J. 260, 177-182), although it has a long insertion of seven residues in the C-terminal region compared with Hb II. On the other hand, it showed low homology (12-20% identity) with other molluscan globins. As well as Hb II, Calyptogena Hb I lacked the N-terminal extension of 7-9 residues characteristic of molluscan intracellular hemoglobins, and the distal (E7) histidine was replaced by glutamine. A phylogenetic tree was constructed from 13 molluscan globins belonging to the five families Aplysiidae, Galeodidae, Potamididae, Arcidae and Vesicomyidae. The globin sequences of Calyptogena (Vesicomyidae) were found to be rather distant from other globin sequences, suggesting that they might conserve a primitive form of molluscan globins.

Amino Acid Sequence↗
PubMed1989

Cloning and sequencing of the gene for Tetrahymena calcium-binding 25-kDa protein (TCBP-25).

With the intention of studying calcium-dependent ciliary reversal in Tetrahymena, we isolated a Tetrahymena calcium-binding protein of 10 kDa (TCBP-10) which was not calmodulin and reported its properties (Ohnishi, K., and Watanabe, Y. (1983) J. Biol. Chem. 258, 13978-13985). However, immunoblotting with an antiserum against TCBP-10 and sequencing of the cDNAs and partial genomic DNAs for this calcium-binding protein prove that this previously reported TCBP-10 is the degraded product of a 25-kDa calcium-binding protein. Thus, we correct the name of the protein from TCBP-10 to TCBP-25. From the analysis of the cDNA for TCBP-25, it is shown to be composed of 218 amino acid residues and its molecular weight is estimated to be 24,702. This protein is predicted to contain four EF-hand-type calcium binding domains and to be a member of the calmodulin family. Little sequence homology with other proteins was shown by a computer search, except in the EF-hand regions. The special feature of TCBP-25 is that the distance between calcium-binding domains II and III is extraordinarily long for a calmodulin family protein having four calcium-binding domains. The genomic DNA for TCBP-25 contains two introns situated at short distances before calcium-binding domains I and III, implying gene duplication in genealogy.

Amino Acid Sequence↗
PubMed1989

Primary structure of the silk fibroin light chain determined by cDNA sequencing and peptide analysis.

A cDNA clone, pFL18, carrying a putative full-length fibroin light chain (L-chain) sequence was isolated and its nucleotide sequence was determined. This revealed the presence of an open reading frame corresponding to a polypeptide with 262 amino acid residues. The sequence was concluded to be that of the L-chain with its signal peptide because corresponding amino acid sequences for the seven tryptic and the four chymotryptic peptides from the purified L-chain were all included and an N-terminal region having typical properties of a signal peptide was present. The N terminus of the mature form of L-chain was identified as N-acetyl serine by analyzing the acyl-dansylhydrazide derived from the N-acyl-amino acid which had been released from the N-terminal blocked chymotryptic peptide by the acylamino acid-releasing enzyme. It was suggested that a signal peptide had cleaved between Pro18 and Ser19, yielding a mature L-chain polypeptide consisting of 244 amino acid residues. The molecular weight of the L-chain was calculated to be 25,800 including the N-acetyl group. The L-chain contained three Cys residues, two of which were suggested to form an intramolecular disulfide linkage, leaving the third one at the most C-terminal position and in a relatively hydrophilic region as the most probable site of disulfide linkage with the fibroin heavy chain.

Amidohydrolases↗
PubMed1989

Amino acid sequences of the two major isoforms of troponin C from crayfish.

The primary structure of the two major isoforms (alpha and gamma) of troponin C (TnC) from crayfish tail muscle has been determined by the application of manual and automated Edman degradation procedures to fragments generated by suitable chemical and proteolytic cleavages. Both amino acid sequences commence with an acetylated methionyl residue and contain 150 amino acid residues, including a single proline residue at position 29 and 2 residues of tyrosine at positions 95 and 102. No cysteine or tryptophan are present. The molecular weights calculated for alpha- and gamma-TnC are 17,157 and 16,974, respectively. The two crayfish proteins are invariable at 129 positions and conserved at 11 others. Pairwise comparisons show that the two sequences are 33-39% identical with those of seven TnCs reported so far and 39% identical with that of bovine brain calmodulin. The N-terminal end of about 10 residues, found in vertebrate TnCs, is absent in crayfish TnCs. In the latter proteins, domains I and III appear as abortive Ca2+-binding sites due to nonconservative amino acid replacements at the key Ca2+-coordinating positions in their loops. The remaining two Ca2+-binding loops (II and IV) show a remarkable similarity with the Ca2+-specific loops (I and II) found in vertebrate TnCs. These findings are consistent with the Ca2+-binding data (Wnuk, W. (1989) J. Biol. Chem. 264, 18240-18246) which indicate the presence of two Ca2+-specific sites in crayfish TnCs. These two sites display the same affinity for Ca2+ (log KCa = 4.3) on gamma-TnC but differ in their affinity (log KCa = 6.0 and 4.1) on alpha-TnC. The only structural difference between the dodecapeptide loops II and IV in both alpha- and gamma-TnC, which correlates with the existence of the high affinity (log KCa = 6.0) Ca2+-specific site on alpha-TnC, is position 11 occupied by a methionyl residue in the loop IV of alpha-TnC as opposed to negatively charged residues found in the other three loops. This suggests that the high affinity Ca2+-specific site on alpha-TnC is located in domain IV. Since the Ca2+-binding studies show that the formation of the complex of crayfish troponin I (TnI) with alpha- and gamma-TnC increases significantly the affinity of only one of their two Ca2+-specific sites and this TnI-sensitive site is not the high affinity Ca2+-specific site on alpha-TnC, we conclude that the binding of Ca2+ to site II controls the Ca2+-dependent interaction between crayfish TnCs and TnI.

Amino Acid Sequence↗
PubMed1989

Pentylenetetrazole-induced changes of the single potassium channel in primary cultured cerebral cortical neurons.

To elucidate the behavior of the single ionic channels of cerebral cortical neurons during bursting activity, the effects of pentylenetetrazole (PTZ) on a single potassium channel of primary cultured cerebral cortical neurons from mice were examined. All of the examined 10-day-old primary cultured neurons of the cerebral cortex showed clear bursting activity after extracellular application of PTZ using whole-cell patch-clamp recording. Less than half of the examined single potassium channels, both outward and inward, of the 2- and 3-day-old as well as 6-10-day-old primary cultured cerebral cortical neurons showed the bursting-type open-close state by application of PTZ. The PTZ-sensitive single potassium channels were found in the voltage-dependent as well as calcium-activated channels.

Animals↗
PubMed1989

Minimum enzyme unit for Na+/K+-ATPase is the alpha beta-protomer. Determination by low-angle laser light scattering photometry coupled with high-performance gel chromatography for substantially simultaneous measurement of ATPase activity and molecular weight.

The oligomeric state of canine renal NA+/K+ -ATPase solubilized by octaethylene glycol n-dodecyl ether (C12E8) was studied by means of low-angle laser light scattering photometry coupled with high-performance gel chromatography (HPGC). At around 0 degree C the solubilized enzyme was separated into the (alpha beta)2-diprotomeric and alpha beta-protomeric protein components with Mr values of 302,000 +/- 10,000 and 156,000 +/- 4,000, respectively, in approximately equal quantities. As the temperature of chromatography was increased toward 20 degrees C, the two protein components converged into a single major component. The Mr of this component depended on the monovalent cation included in the elution buffer, and was 255,000 or 300,000 in the presence of 0.1 M NaCl or 0.1 M KCl, respectively. A computer simulation technique showed that the solubilized enzyme was in a dissociation-association equilibrium of 2 protomers = diprotomer at 20 degrees C, and the difference in apparent Mr of the solubilized enzyme between the two species of monovalent cation was interpreted by an association constant (Ka) in the presence of 0.1 M KCl that was about 50-fold larger than in the presence of 0.1 M NaCl. In order to measure ATPase activity and Mr of the solubilized enzyme simultaneously, a TSKgel G3000SW column had been equilibrated and was eluted with an elution buffer containing 0.30 mg/ml C12E8 and 60 microgram/ml phosphatidylserine (bovine brain) as well as the ligands necessary for the enzyme to exhibit the activity at pH 7.0 and 20 degrees C. The solubilized enzyme was always eluted as a single protein component irrespective of the the amount of the protein applied to the column, ranging between 240 and 10 microgram. The Mr of the protein component, however, decreased from 214,000 and 158,000 with the decrease of the protein amount. The specific ATPase activity, however, remained constant at a level of 64 +/- 4% of that of the membrane-bound enzyme even in the range of protein concentration sufficiently low as to allow the enzyme to exist only in the protomeric form. Thus, the alpha beta-protomer is concluded to be the minimum functional unit for the ATPase activity. The value of Ka obtained from the concentration-dependent dissociation curve was 5 . 10(5) M-1 for the enzyme turning over, and 1.1 . 10(7) M-1 for the enzyme inhibited with ouabain. It was discussed, based on the values of Ka obtained, that the enzyme would exist as the diprotomer or the higher oligomer in the membrane.

Animals↗
PubMed1989

Protozoan myoglobin from Paramecium caudatum. Its unusual amino acid sequence.

A protozoan myoglobin (or monomeric hemoglobin) was isolated from Paramecium caudatum, and its complete amino acid sequence determined. It consists of 116 amino acid residues with a molecular mass of 12,565 daltons, this being much smaller than sperm whale myoglobin by 37 residues and even smaller than a bacterial hemoglobin from Vitreoscilla by 30 residues in terms of the monomer unit. A computer search showed no notable sequence homology with other hemoproteins. It contains two histidine residues at positions 68 and 84, but other lines of evidence seem to be needed to complete their final alignment. This is the first protozoan myoglobin to be sequenced. It may provide us with a new molecular basis for a further understanding of myoglobin-hemoglobin chemistry and their evolution.

Amino Acid Sequence↗
PubMed1989

Primary structure of a dimeric haemoglobin from the deep-sea cold-seep clam Calyptogena soyoae.

The heterodont clam Calyptogena soyoae, living in the cold-seep area of the upper bathyal depth of Sagami Bay, Japan, has two homodimeric haemoglobins (Hb I and Hb II) in erythrocytes. The complete amino acid sequence of 136 residues of C. soyoae Hb II was determined. The sequence showed low homology with any other globins (at most 20% identity) and lacked the N-terminal extension of seven to nine amino acid residues characteristic of all the molluscan haemoglobins sequenced hitherto. Although the subunit assembly of molluscan haemoglobin is known to be 'back-to-front' relative to vertebrate haemoglobin, C. soyoae Hb II is unlikely to undergo such a subunit assembly because it lacks homology in the sequence involving subunit interaction. These structural features suggest that C. soyoae haemoglobin may have accomplished a unique molecular evolution. The distal (E7) histidine residue of C. soyoae Hb II is unusually replaced by glutamine. However, the oxyhaemoglobin is stable enough to act as an O2 carrier, since the autoxidation rate at near physiological temperature (3 degrees C) is about 3 times lower than that of human haemoglobin at 37 degrees C. H.p.l.c. patterns of peptides (Figs. 5-7), amino acid compositions of intact protein and peptides (Table 1) and amino acid sequences of intact protein and peptides (Tables 2 and 3) have been deposited as Supplementary Publication SUP 50150 (11 pages) at the British Library Document Supply Centre, Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies may be obtained on the terms indicated in Biochem. J. (1989) 257, 5.

Amino Acid Sequence↗
PubMed1989

Amino acid sequence of crayfish troponin I.

Troponin I is the actomyosin ATPase inhibitory subunit present in the thin filament regulatory complex. The complete amino acid sequence of crayfish tail muscle troponin I has been determined. The protein is composed of 201 amino acid residues and has a molecular weight of 23,547. The N terminus is blocked, likely by an acetyl group. Crayfish troponin I shows a rather low (20-25%) sequence identity with vertebrate troponin Is as compared to the 60-82% identity within the vertebrate phylum. Similar to vertebrate cardiac troponin I, crayfish troponin I contains a 30-residue-long N-terminal extension. In crayfish troponin I, this segment bears significant sequence homology with the heavy or light chains of particular myosins. The actin-binding domain of crayfish troponin I, which displays 57% sequence homology with vertebrate troponin Is, possesses 2 unusual trimethyllysine residues. The consensus sequence of this domain in five troponin Is is as follows: D-L-R-G-K-F-X-R*-P-X-L-R*-R*-V, where R+ stands for Arg/Lys, R* for Arg/trimethyllysine, and X for any amino acid residue. Troponin I possesses two Ca2+-dependent interactive sites for troponin C; one partly overlaps with the actin binding domain and is highly conserved, and the other, corresponding to the 30-residue-long segment following the N-terminal extension in vertebrate cardiac and crayfish troponin I, is poorly conserved in the different troponin Is. Troponin I also interacts with troponin T. The consensus sequence for the interacting site on troponin I is as follows: h-D- -X-D- -R+-Y-D-h-E-h, where h stands for a hydrophobic residue, D- for Asp/Glu, R+ for Arg/Lys, and X for any residue. The five troponin Is further possess one more 15-residue-long segment of high sequence identity near the C terminus. Its evolutionary conservation suggests that this domain is involved in protein-protein interaction.

Actins↗