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Biomedical subjects

K Takeda

Publications and source records attributed to K Takeda.

At least 793 records · Page 44Linked to original sources
PubMed1993

[Flow cytometry study on purification of human eosinophils and cell function].

The eosinophil is a well-known leukocyte acting as an effector cell in the allergic reaction mechanism. The application of appropriate materials has led to more exact results from allergic examinations. In an effort to further improve analysis, we established a novel purification method for eosinophils using the flow cytometry (PCM) of peripheral blood and bronchoalveolar lavage fluid (BALF) leucocytes from healthy and allergic subjects. We examined the function of these cells in chemotaxis by platelet activating factor (PAF) and recombinant human (rh) IL-5. We obtained following results. First, we were able to separate human eosinophils containing autofluorescence substance, which was detectable by FCM employing a 450 nm argon ion laser. Second, the purity and recovery rate of the eosinophils were 90.1 +/- 4.2% and 32.1 +/- 7.6% in the healthy subjects who had no peripheral eosinophilia (< 6%) and 93.7 +/- 4.4% and 37.2 +/- 7.5% in the allergic subjects who had eosinophila (> 6%). A relationship was readily apparent between the peripheral and purified eosinophil counts in the healthy subjects (r = 0.62). Autofluorescence of the eosinophil fraction on PCM was further found to be decreased in patients with marked eosinophilia because of an increase in hypodense eosinophils. Third, highly purified eosinophils (76%) were also obtained from the 6.5% eosinophils present in the bronchoalveolar lavage fluid of one bronchial asthma patient. Fourth, the maximal chemotaxis of these eosinophils was shown at 10(-6) M of platelet activating factor (PAF) and at 1 micrograms/ml of IL-5 in a dose-dependent manner. This activity in allergic patients was accelerated compared with that in healthy subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

[Pharmacokinetic study on aspoxicillin transfer into pulmonary and tracheal tissues].

Each of 36 patients who underwent tracheotomy for removal of malignant or benign tumors or for treatment of pneumothorax was infused with 2 g of aspoxicillin (ASPC, Doyle injection) intravenously over 1-hour period. ASPC concentrations determined at 1 postoperative time-point in tissues of the lung and trachea and in serum of each patient were analyzed pharmacokinetically to elucidate the transfer of ASPC to the thoracic tissues. The preventive effect of ASPC against postoperative infections was also investigated in 39 tracheotomy patients. 1. The analysis of ASPC concentrations in 36 patients with tracheotomy gave the following results; 1) The peak blood level (about 80 micrograms/ml) was attained at the end of infusion. The serum level then decreased with time to below about 10 micrograms/ml at 6 hours after the start of infusion, with an elimination half-life of about 1.4 hours, which was comparable to that in healthy adults. 2) Peak levels in the lung and tracheal tissues were achieved at about 30 minutes after the start of infusion, at levels of about 30 and 40 micrograms/g, respectively, which decreased to about 5 micrograms/g in both tissues at 6 hours after the start of infusion. 2. Thirty nine patients who were treated with ASPC before operation were examined for the preventive effect of ASPC against postoperative infections for 1 week after operation. No postoperative infection was noted in any patients and ASPC was found to be useful for prevention of postoperative infections. 3. No side effects or abnormal laboratory findings were noted in any patients. Based on the results of the transfer into the tissues of respiratory organs and preventive effect against postoperative infections, we have concluded that ASPC is useful for prevention of infections after thoracic operation.

Adolescent↗
PubMed1993

[Bronchial asthma pediatric field].

The role of eosinophils and their activation products in the development of asthma in children has been reviewed, based on the recent data from our laboratory. The levels of the peripheral blood eosinophils and eosinophil cationic protein (ECP), and bronchial sensitivity to methacholine (PC20) were compared among three groups: Group A, mite-sensitive asthmatic children, Group B, mite-sensitive non-asthmatic children having the same level of IgE antibody against mite(Df) as Group A, and Group C, mite-insensitive normal control children. Group A had significantly higher eosinophil and ECP levels than Group B, and Group B had also higher levels than Group C. The PC20 values in Group A were significantly lower than those in Group B, and the values in Group B were also significantly lower than those in Group C. These results have suggested that activation of eosinophil is an important contributing factor for the development of asthma in children in addition to allergic sensitization.

Age Factors↗
PubMed1992

Evidence that [3H]glutamate binding sites are masked by biologically relevant endogenous factor on cell membranes of frog spinal cord.

We identified the possible endogenous factor effective to modulate the binding of [3H]-labeled excitatory amino acid agonists and antagonists in the 100,000 x g supernatant of Triton X-100 (0.01%)-treated cell membranes from frog spinal cords. The factor inhibited the binding of [3H]glutamate to Triton X-100-treated cell membranes, to which the binding capacity of [3H]glutamate increased much more than that to intact cell membranes. The binding capacities of [3H]AMPA (an AMPA type agonist) and [3H]CPP (an NMDA type antagonist) to cell membranes remained low by Triton treatment, but they were enhanced significantly by the addition of the factor. The effect of the factor on the [3H]kainate binding was hardly observable. The factor may provide key information on receptor structures and the classification of receptor types concerning excitatory amino acids in the mammalian central nervous system.

Animals↗
PubMed1992

Expression of VLA-4 on thymocytes. Maturation stage-associated transition and its correlation with their capacity to adhere to thymic stromal cells.

The present study investigates the expression of VLA-4 on thymocytes at various stages of maturation and their capacity to adhere to thymic stromal cells. Whole thymocytes were stained with anti-CD4 and anti-CD8, as well as anti-VLA-4 antibodies. Flow microfluorometric analyses revealed that a) most of CD4-8- (double negative DN) and CD4-8intermediate thymocyte populations expressed large amounts of VLA-4, b) the levels of VLA-4 were considerably and markedly reduced on CD4+8+ (double positive DP) and single positive (SP) (CD4+8- or CD4-8+) populations, respectively. This contrasted with an increase in the levels of LFA-1 along with thymocyte maturation. DN, DP, and SP subsets were isolated and examined for their capacity to express VLA-4 and to adhere to fibronectin (FN) molecules as well as thymic stromal cells expressing FN. DN, DP, and SP subsets were confirmed to express the respective high, low, and very low levels of VLA-4, respectively. Approximately 70% of DN thymocytes became bound to FN-precoated culture plates, whereas 30 to 40% of DP and only 10 to 20% of SP cells adhered to FN. Similar patterns of adhesion were observed between these thymocyte subsets and thymic stromal monolayers. The binding of the DN subset to FN-plates or thymic stromal monolayers was inhibited only marginally by the RGDS peptide, but was efficiently inhibited by V10 peptide (cell-binding sequence that is located in the V region on FN and reacts with the VLA-4 integrin) or anti-VLA-4 antibody. Anti-VLA-4 antibody plus RGDS peptide strongly inhibited DN cell binding to FN-coated plates and thymic stromal monolayers. These results indicate that i) VLA-4 expressed on DN thymocytes functions as an important integrin for interacting with thymic stromal cells; ii) the expression level of this integrin decreases with the progress of thymocyte maturation, and iii) most of the mature thymocytes (SP) are rendered less adhesive to thymic stromal cells by reducing the level of VLA-4 expression.

Animals↗
PubMed1992

[Hyperresponsiveness of TSH and prolactin and impaired responsiveness of GH in Japanese patients with isolated ACTH deficiency].

Two hundred and forty-one cases of isolated ACTH deficiency have been reported in Japan since 1969. Pituitary hormone responsiveness to stimulation tests before and after hydrocortisone supplementation was investigated in these cases. Plasma ACTH level showed no or little change in response to lysine vasopressin, metyrapone, CRF or insulin-induced hypoglycemia in 97.3-100% of the cases. Serum GH level changed little or not at all in response to GRF, insulin-induced hypoglycemia, glucagon, 1-dopa and arginine in 26.9, 29.3, 40.0, 50.0 and 56.1%, respectively. Serum TSH and prolactin (PRL) levels showed hyperresponse to TRH in 34.7 and 35.6%, respectively. After hydrocortisone therapy, GH secretion was more responsive than before therapy in 78.9% of the cases. After supplementation, TSH level was less responsive to TRH stimulation than before therapy in 59.3% of the cases. After hydrocortisone supplementation, TSH response to TRH decreased in 75% of ACTH-deficient patients without primary hypothyroidism but did not decrease in more than half of those with primary hypothyroidism. TSH response to TRH decreased after supplementation in 76.5% of the patients with TSH hyperresponsiveness before therapy, and increased after therapy in 66.7% of those with normal TSH responses before therapy. After supplementation, PRL response to TRH was less than that before therapy in 43.5% of ACTH--deficient patients, and greater than that before therapy in 30.4%. PRL response to TRH decreased after therapy in 66.7% of the patients with PRL hyperresponsiveness before therapy, and increased in 63.6% of those with normal PRL response before therapy. Primary hypothyroidism and Hashimoto's thyroiditis were complicated in 21.6 and 11.6%, respectively, of the 241 patients with isolated ACTH deficiency. In patients who had TSH hyperresponsiveness and/or high basal TSH levels and PRL hyperresponsiveness and/or high basal PRL levels, primary hypothyroidism was complicated in 58.4 and 42.3%, respectively. Hashimoto's thyroiditis was complicated in 29.8 and 20.5%, respectively, of these patients. Pituitary cell antibody (PCA) was detected in 36.6% of ACTH-deficient patients who were examined. Pituitary cell surface antibody (PCSA) to AtT-20 cells and GH3 cells was detected in 50.0 and 28.0% of the examined cases, respectively. The prevalence of PCA and PCSA did not differ between TSH-hyperresponsive patients and those with normal TSH basal levels and response, whereas PCA and PCSA were significantly more prevalent in PRL-hyperresponsive patients than in those with normal PRL levels and response. An empty sella was found in 30.2% of the examined case.(ABSTRACT TRUNCATED AT 400 WORDS)

Adrenocorticotropic Hormone↗
PubMed1992

Voltage-dependent calcium current and the effects of adrenergic modulation in rat aortic smooth muscle cells.

Smooth muscle cells from rat aorta were cultured in defined, serum-free medium and studied using whole-cell patch-clamp techniques. Under conditions designed to isolate currents through Ca channels, step depolarizations produced inward currents which were fast in onset and inactivated rapidly, with little sustained inward current being observed. Both Ni and Cd blocked these currents, with Ni being effective at 50 microM. Removal of external Na or addition of 1 microM tetrodotoxin had no effect. Peak inward currents were attained at about -15 mV, with half-maximal activation at -41 mV using -80 mV holding potentials. The transient inward currents were reduced by depolarized holding potentials, with half-maximal steady-state inactivation at -48 mV. In three of the 98 cells studied, small maintained inward currents were observed with a -40 mV holding potential. The Ca channel antagonist nicardipine (5 microM) blocked the transient inward current while neither of the dihydropyridine Ca channel agonists S(+)202 791 and (-)BAY K 8644 produced a significant augmentation of sustained inward current. At 10 microM, both noradrenaline and adrenaline but not phenylephrine decreased the peak inward current. This inhibition was unaffected by a variety of adrenoceptor antagonists and was also observed when internal solutions having high Ca buffering capacity were used, but was absent when GDP-beta-S instead of GTP was included in the pipette solution. The main conclusions from this study are that under our cell culture conditions, rat aortic smooth muscle cells possess predominantly a transient, low-threshold-activated inward Ca current and that this Ca current is inhibited by certain adrenoceptor agonists but with a quite atypical adrenoceptor antagonist pharmacology.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1992

Downstream region of the human tyrosinase-related protein gene enhances its promoter activity.

We have cloned and sequenced the human genomic DNA segments encoding the 5'-flanking region and the first two exons of the tyrosinase-related protein (TRP) gene, a pigment cell-specific gene. Functional analysis of its promoter suggests that the downstream region of the TRP gene, including the first intron, enhances the transient expression of the luciferase gene under control of the TRP gene promoter about 16- to 20-fold. This enhancer-like activity is detected not only in melanoma cells but also in HeLa cells whose TRP gene expression is assumed to be repressed. We suggest a possibility that the downstream region is not sufficient to confer pigment cell-specific expression, but is required for efficient transcription of the TRP gene in pigment cells.

Animals↗
PubMed1992

Identification of the reaction products of the purified hyaluronidase from stonefish (Synanceja horrida) venom.

Recently we purified to homogeneity hyaluronidase from stonefish (Synanceja horrida) venom, for the first time from a marine source [Poh, Yuen, Chung & Khoo (1992) Comp. Biochem. Physiol., in the press]. In the present study the reaction products of the hyaluronidase purified from stonefish venom were analysed. It produced tetra-, hexa-, octa- and deca-saccharides as major end products, but not disaccharides. The structure of the tetrasaccharide product was determined by enzymic analysis, in conjunction with h.p.l.c. and by 1H n.m.r., as GlcA beta 1-3GlcNAc beta 1-4GlcA beta 1-3GlcNAc. Chemical shifts of the structural-reporter-group protons of the constituent monosaccharides for the tetrasaccharide have been assigned. The enzyme did not act on chondroitin sulphate or dermatan sulphate. The results indicate that the stonefish hyaluronidase is an endo-beta-N-acetylglucosaminidase specific for hyaluronate.

Animals↗
PubMed1992

Similar, but not identical, modulation of expression of extracellular matrix components during in vitro and in vivo aging of human skin fibroblasts.

Regulation of the synthesis of procollagen and other extracellular matrix components was examined in human skin fibroblasts obtained from donors of various ages, from fetal to 80 years old (in vivo aged), and in fetal fibroblasts at varying passage levels (in vitro aged). Growth rates and saturation densities of fibroblasts decreased with increasing age of the donor and after passage 20 of fetal fibroblasts. The rates of collagen and proteoglycan synthesis also decreased during both types of aging to about 10-25% of the rate in early passage fetal fibroblasts, whereas the synthesis of total noncollagenous proteins was not greatly affected. Decreased collagen synthesis in both types of aging was correlated with lower steady-state levels of mRNAs for the two subunits of type I procollagen mRNA, although their regulation was not coordinate. Type III collagen mRNA levels also declined in both types of aging. The concentration of fibronectin mRNA also decreased during in vitro aging but more rapidly than the collagen mRNAs, whereas in fibroblasts from 51-80-year-old donors, it was similar to or higher than in early passage fetal fibroblasts. This study suggests that the decreased synthesis of procollagen and proteoglycans in in vivo aged fibroblasts represents changes that are responsible for intrinsic degenerative changes that occur in human skin during aging. Furthermore, although in vitro and in vivo aging were similar in many respects, they were not equivalent, as evidenced by the differences in regulation of fibronectin expression.

Cell Division↗
PubMed1992

Serial change of iodine-123 metaiodobenzylguanidine (MIBG) myocardial concentration in patients with dilated cardiomyopathy.

Serial change of the metaiodobenzylguanidine iodine-123 (123I-MIBG) myocardial concentration was investigated in patients with dilated cardiomyopathy (DCM). Eight DCM patients and 6 control subjects were examined. After the injection of thallium-201 and 123I-MIBG, planar chest images were obtained simultaneously for both tracers in every 30-60 min over 5 h. Serial changes of myocardial uptake ratio (MUR) were compared for both tracers. In DCM, the initial MUR of 123I-MIBG did not differ significantly from that of the controls. The washout of 123I-MIBG from the myocardium, however, was significantly increased in DCM. In particular, the decrease in the early phase (15-45 min) was significantly larger in DCM than in the controls (21.2% +/- 7.5% vs. 5.3% +/- 4.0%, P less than 0.01), showing a significant negative correlation with the left ventricular ejection fraction (r = -0.72 P less than 0.05). For 201Tl, neither the initial MUR nor the washout rate different significantly between the two. Thus, an early rapid decrease of the 123I-MIBG myocardial concentration might characterize DCM and reflect the severity of this disease.

3-Iodobenzylguanidine↗
PubMed1992

Secondary structural changes of metmyoglobin and apomyoglobin in anionic and cationic surfactant solutions: effect of the hydrophobic chain length of the surfactants on the structural changes.

Secondary structural changes of metmyoglobin and apomyoglobin were examined in solutions of sodium alkylsulfates with hydrocarbon numbers of 8 and 12, and alkyltrimethylammonium bromides with hydrocarbon numbers of 10, 12, 14, and 16. The relative proportion of alpha-helical structure was estimated by the curve-fitting method of circular dichroic spectrum. The helical proportions of metmyoglobin and apomyoglobin were 82 and 63%, respectively. The shorter the hydrocarbon chain the surfactant had, the higher the concentration necessary to disrupt the secondary structures of these proteins. However, the helical proportion had a tendency to decrease down to lower values in solutions of the cationic surfactants with short hydrophobic groups. On the other hand, the alpha-helical structure of apomyoglobin was disrupted in lower concentrations of each cationic surfactant than that of metmyoglobin, although the disruptions of the same structures in both the proteins occurred in the same concentration range of each anionic surfactant. It appeared likely that the removal of the heme group unstabilized the myoglobin conformation only in the cationic surfactant solutions.

Anions↗
PubMed1992

Dependence of reaction rate of 5,5'-dithiobis-(2-nitrobenzoic acid) to free sulfhydryl groups of bovine serum albumin and ovalbumin on the protein conformations.

The effect of protein conformations on the reaction rate of Ellman's reagent, 5,5'-dithiobis (2-nitrobenzoic acid) (DTNB) with sulfhydryl (SH) groups of proteins was examined. The stopped-flow method was applied to follow the reaction of DTNB with SH group of two proteins, bovine serum albumin (BSA) and ovalbumin (OVA), at various concentrations of guanidine hydrochloride and urea. The rates for both the proteins were faster in guanidine than in urea. The rate sharply depended on the protein conformations, which were monitored by changes of helix contents on the basis of the circular dichroism measurements. The reaction rate of DTNB with SH groups of BSA was maximal around 2 M guanidine and 5 M urea. On the other hand, the reaction rate of DTNB with OVA was maximal at 3.5 M guanidine, while it gradually increased with an increase in the urea concentration. The amount of reactive SH group participating in the reaction with DTNB was also estimated by the absorbance change at 412 nm. The magnitudes of absorbance change for the reaction with free SH groups of OVA at low concentrations of the denaturants were appreciably smaller than those for BSA with one free SH group. Most of the four SH groups of OVA might react with DTNB above 5 M guanidine, although only a part of them did even at 9 M urea.

Dithionitrobenzoic Acid↗
PubMed1992

Experimental study on Reye's syndrome: inhibitory effect of interferon alfa on acetylsalicylate-induced injury to rat liver mitochondria.

Viral infection and acetylsalicylate (ASA)-induced mitochondrial aberration have been reported to play important roles in the pathogenesis of Reye's syndrome. We report that increasing amounts of ASA (0 to 250 mumol/L) resulted in increases in state 4 respiration and decreases in state 3 respiration in rat liver mitochondria in vitro when using alpha-ketoglutarate and/or beta-hydroxybutyrate as respiratory substrates, but not when using succinate as substrate. Interferon alfa (IFN-alpha) (1.5 to 5 x 10(4)IU/mL, approximately 1/100 the therapeutic dosage for humans) and interleukin-1 (IL-1) (1.5 to 2 x 10(4)IU/mL, nearly equivalent to the therapeutic dosage) decreased the severity of the above effects via interaction with mitochondrial membranes. Interferon gamma (IFN-gamma) and interleukin-2 (IL-2) had no such protective effect. Electron microscopic observation indicated that IFN-alpha prevented the induction of mitochondrial swelling by ASA. These results suggest that IFN-alpha may prove to be effective for the treatment of Reye's syndrome.

Animals↗