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Y Takeda

Publications and source records attributed to Y Takeda.

At least 523 records · Page 29Linked to original sources
PubMed1995

Identification of glycosaminoglycans using high-performance liquid chromatography on a hydroxyapatite column.

Glycosaminoglycans (heparin, heparan sulfate, dermatan sulfate, chondroitin sulfate, and hyaluronic acid) were labeled with a fluorescent reagent, 2-aminopyridine. The fluoro-labeled glycosaminoglycans were subjected to high-performance liquid chromatography on a hydroxyapatite column. The binding property of each glycosaminoglycan to hydroxyapatite was different. The structural properties of glycosaminoglycans bound to hydroxyapatite were then investigated using chemical desulfated or enzymic depolymerized glycosaminoglycans. This revealed that the sulfate content and molecular weight of the glycosaminoglycans correlated with their binding properties to hydroxyapatite. Desulfated dermatan sulfate but not desulfated chondroitin 6-sulfate bound to the hydroxyapatite. These data indicate that iduronic acid residues of glycosaminoglycans are important for the binding property. The method described which uses hydroxyapatite columns facilitates rapid separation and microanalysis of the glycosaminoglycans, especially dermatan sulfate and chondroitin sulfate.

Aminopyridines↗
PubMed1995

Requirement of AP-1 for ceramide-induced apoptosis in human leukemia HL-60 cells.

Ceramide has emerged as a novel lipid mediator in cell proliferation, differentiation, and apoptosis. In this work, we demonstrate that the levels of c-jun mRNA, c-Jun protein, and DNA binding activity of a nuclear transcription factor AP-1 to 12-o-tetradecanoylphorbol 13-acetate responsive elements all increased following treatment with the cell-permeable ceramide, N-acetylsphingosine in human leukemia HL-60 cells. N-Acetylsphingosine (1-10 microM) increased the levels of c-jun mRNA in a dose-dependent manner, and maximal expression was achieved 1 h after treatment. Increase of c-jun expression treated with 5 microM N-acetyldihydrosphingosine, which could not induce apoptosis, was one third of that with 5 microM N-acetylsphingosine. Ceramide-induced growth inhibition and DNA fragmentation were both prevented by treatment with curcumin, 1,7-bis[4-hydroxy-3-methoxy-phenyl]-1,6-heptadiene-3,5-dione (an inhibitor of AP-1 activation), or antisense oligonucleotides for c-jun. These results suggest that the transcription factor AP-1 is critical for apoptosis in HL-60 cells and that an intracellular sphingolipid mediator, ceramide, modulates a signal transduction inducing apoptosis through AP-1 activation.

Apoptosis↗
PubMed1995

A generalized epistasis analysis as a method of reconstruction of developmental process and its application to Drosophila dorso-ventral axis formation.

Epistasis analysis has been used in molecular genetics to infer cause and effect relationships among loci that decide a developmental fate. In this paper, in order to investigate the logical background of the rule that relates epistasis and causal relation, a mathematical epistasis analysis is formulated. An "orderliness index" is introduced by which the cause-and-effect relation can systematically be extracted from genotype-phenotype data. This method is applied to Drosophila melanogaster dorso-ventral axis formation and it is shown that the method of reconstructing the framework of the causal relation between a locus and its sign (activation or inhibition) as an "orderliness diagram" from eight groups of the genes. From the diagram it can be seen that the dorsal gene works as a morphogen. The difference between orderliness diagrams of the dorsal and ventral sides of the embryo shows that the cells on the ventral side receive the signal and the fate of the cells on the dorsal side is default in the wild-type embryo.

Animals↗
PubMed1995

Progression toward metastatic phenotype with loss of growth-inhibiting tumor-cell/cell interactions in vivo.

Five autonomous sublines, T4-O1320, T4-O1320CY, T4-O1165, T4-O1145 and T4-O196, were established from the transplantable hormone-dependent mouse mammary tumor, TPDMT-4, by passaging under different conditions. These autonomous tumors were characterized by rapid growth in DDD virgin mice and the parental TPDMT-4 by no growth in these mice. Thus, 10(5) T4-O1320, 2 x 10(4) T4-O1320CY, 2 x 10(3) T4-O1165, 2 x 10(3) T4-O1145 and 10(3) T4-O196 cells were co-injected with 5 x 10(5) TPDMT-4 cells into virgin mice to determine whether or not hormone-dependent tumor cells influence the growth of autonomous tumor cells. TPDMT-4 cells retarded the growth of T4-O1320 and T4-O1320CY tumors but accelerated that of T4-O1165, T4-O1145 and T4-O196. Irradiated TPDMT-4 cells stimulated the growth of all the sublines except T4-O1320. In 3-dimensional collagen-gel culture, T4-O1320 and T4-O1320CY cells formed branched or stellate structures similar to normal mammary glands, as did TPDMT-4, but T4-O1165, T4-O1145 and T4-O196 cells grew as rounded masses with knobs and showed a completely different morphology. T4-O1165, T4-O1145 and T4-O196 cells, but not the others, had lung-colonizing ability. Chromosomal aberration was found in T4-O1320CY and T4-O196 but not in the others. Thus, the susceptibility of autonomous subline tumor cells to growth-inhibitory regulation from the parental hormone-dependent tumor cells correlated well with growth morphology within collagen gels and metastatic ability, but not with chromosomal aberration. The results suggest that metastatically-competent tumor-cell variants, once they appear, may have a growth advantage in hormone-dependent mammary tumors.

Animals↗
PubMed1995

Effects of an antibiotic protease inhibitor, actinonin on the growth within collagen gels of non-metastatic and metastatic mouse mammary tumors of the same origin.

Of five autonomous sublines established independently from the transplantable hormone-dependent mouse mammary tumor, TPDMT-4, three but not two acquired metastatic potential. In in vitro culture using collagen gels, actinonin, an antibiotic protease inhibitor exerted a stronger growth-inhibiting effect on the metastatic than on the parent and non-metastatic tumors. Zymographic analysis demonstrated the active forms of gelatinases in the metastatic but not in the non-metastatic sublines and the complete inhibition of the enzyme activities by actinonin. Gelatinases/type IV collagenases might play an important role in tumor progression towards metastatic phenotype and actinonin may suppress tumor growth through inhibiting collagenase.

Animals↗
PubMed1995

High expression of c-kit in K562YO cells due to the prolonged half-life of its mRNA: the effects of modification with serine/threonine kinase signals.

We previously reported that the K562 cell line K562YO expressed a high level of the c-kit gene. In this study, we analyzed the mechanism of this expression and investigated the effects of the serine/threonine kinases such as protein kinase C (PKC) and cyclic adenosine 3',5'-monophosphate (cAMP)-dependent kinase (PKA) on it. The half-life of the c-kit mRNA in K562YO cells was greater than 10 hours, compared with 2 hours in the original K562 cells, which expressed a very low level of c-kit mRNA. This prolonged half-life can contribute to the high level of c-kit expression in K562YO cells. Cycloheximide (CHX), a protein synthesis inhibitor, caused increases in c-kit mRNA levels in K562YO cells. 12-O-tetradecanoylphorbol-13-acetate (TPA), by which PKC was activated at first and downregulated in a late phase, gradually decreased c-kit mRNA in K562YO cells until 9 hours and then returned to the control level 24 hours after treatment. TPA also rapidly decreased c-kit protein level on the membranes. In whole cells, c-kit protein was also decreased 6 hours after incubation with TPA. Calphostin C, a light-dependent PKC inhibitor, decreased c-kit mRNA levels within 30 minutes in a light-dependent manner. It also decreased c-kit protein in whole cells 2 hours after the addition. However, it increased the amount of c-kit protein on the cell surfaces. Dibutyryl cyclic AMP (dbc-AMP) increased c-kit mRNA as well as c-kit protein on membranes and in whole cells. Run-on transcriptional assay suggested that the agent (dbc-AMP) enhanced the transcription rate of the gene. These results suggest that c-kit protein on the membranes is downregulated by PKC activation and upregulated by PKC inhibition. In the whole cell lysate, c-kit proteins are decreased by PKC inhibition through downregulation of mRNA. On the other hand, the elevation of an intracellular cAMP level causes upregulation of both the mRNA and c-kit protein on membranes and in whole cells through enhanced transcription. Thus, c-kit gene expression is apparently modulated by PKC and PKA.

Bucladesine↗
PubMed1995

CNS myelinogenesis in vitro: time course and pattern of rat oligodendrocyte development.

Oligodendrocyte precursor cells that develop into myelin-forming cells of the central nervous system (CNS) were cultured from newborn rat brain to study how they proliferate and differentiate in normal conditioning medium, and their cell development was characterized by scanning electron microscopy (SEM) observation and immunocytochemical studies. We have identified A2B5-negative pre-O2A progenitor cells (so-called "type-1" oligodendrocytes) in the secondary cultures on the astrocyte feeder layer. These cells are very small (diameter: 3.5 microns), round, and glossy, and develop into the process-bearing O2A progenitor cells (called "type-2" oligodendrocytes), which also express myelin basic protein (MBP) both in the cell body and in their cell processes. Finally, they develop into mature oligodendrocytes (called "type-3" oligodendrocytes). After MBP expression is elicited in these cells and MBP accumulates in the cell process in the area in contact with the axon, these cells are capable of forming the myelin sheath. Therefore, we examined the mechanism of myelin-sheath formation of "type-3" oligodendrocytes using video time-lapse movies, and demonstrated that these cells initially sent out processes to search for axons several times before the onset of myelination. Then thick filopodia extended towards the axon, and at the same time, the axonal part of neuron moved forward. Finally the ruffling lamellipodial parts wrapped up the axon similarly to a transverse wave with the secured thick filopodial process on the axon acting as scaffolding. These results suggest that our experimental systems are useful in studying normal oligodendrocyte development and their cellular biochemistry, as well as investigating the mechanism of myelin formation by oligodendrocytes.

Animals↗
PubMed1995

In vivo regulation of rat neutrophil apoptosis occurring spontaneously or induced with TNF-alpha or cycloheximide.

We previously demonstrated that human TNF-alpha induces rapid apoptosis of human neutrophils. To understand better the in vivo significance of neutrophil apoptosis, we examined spontaneous, recombinant human and mouse TNF-alpha- or cycloheximide-induced apoptosis of normal peripheral blood neutrophils (PBN), PBN from rats injected i.p. with proteose peptone or a streptococcus preparation, OK-432 (inflammatory PBN), peritoneally exudated neutrophils (PEN) obtained after a proteose peptone injection, and normal bone marrow neutrophils. The following observations were made. 1) Normal PBN responded to TNF-alpha, but PEN, normal bone marrow neutrophils, and inflammatory PBN at 12 h after stimulation did not. 2) The sensitivity to TNF-alpha of the inflammatory PBN started to decrease at 3 h, was lowest at 12 h, and was almost restored at 52 h after stimulation. 3) Spontaneous apoptosis of normal and inflammatory PBN reached 25% at 12 h after in vitro incubation, but that of PEN and normal bone marrow neutrophils was very low over this period. 4) The sensitivity to cycloheximide (6 h incubation) was high for normal PBN and bone marrow neutrophils, but low for PEN and inflammatory PBN after 12 h. 5) 125I-rhTNF-alpha binding of bone marrow neutrophils was significantly lower than that of normal and inflammatory PBN and PEN. 6) TNF-alpha-induced apoptosis of normal or inflammatory PBN and bone marrow neutrophils was enhanced by treatment with low doses of cycloheximide that alone were barely able to induce neutrophil apoptosis; however, apoptosis of PEN was not. The mechanisms and in vivo significance of these phenomena are discussed.

Animals↗
PubMed1995

Proximal subtotal gastrectomy for the treatment of carcinoma of the upper third of the stomach: its indications based on lymph node metastasis and perigastric lymphatic flow.

To clarify the indications for a proximal subtotal gastrectomy in the treatment of carcinoma in the upper third of the stomach based on lymph node metastases, 1055 patients in whom either a D2 or greater lymph node removal was performed were reviewed. In the patients in which the lesion was confined to the upper stomach and did not invade beyond the muscularis propria of the stomach wall, no metastases to either the lymph nodes above and below the pylorus or the lymph nodes along the greater curvature were observed. A lymphatic flow study revealed a minimal flow to these nodes from the upper stomach in patients without lymph node metastasis, but in cases with lymph node metastases the lymphatic flow changed. The indications for a proximal subtotal gastrectomy for a carcinoma of upper third of the stomach therefore must fulfill the following two conditions: (1) The deepest layer of cancerous invasion does not extend beyond the muscularis propria of the stomach wall, and (2) No macroscopic evidence of lymph node metastasis can be detected during surgery.

Case-Control Studies↗
PubMed1995

Effect of knee flexion on the in situ force distribution in the human anterior cruciate ligament.

This study was conducted to evaluate the effect of applied load on the magnitude, direction, and point of tibial intersection of the in situ forces of the anteromedial (AM) and posterolateral (PL) bands of the human anterior cruciate ligament (ACL) at 30 degrees and 90 degrees of knee flexion. An Instron was used to apply a 100 N anterior shear force to 11 human cadaver knees, 6 at 30 degrees of knee flexion and 5 at 90 degrees of knee flexion. A Universal Force Sensor (UFS) recorded the resultant 6 degree-of freedom (DOF) forces/moments. Each specimen then underwent serial removal of the AM and PL bands. With the knee limited to 1 DOF (anteroposterior), tests were performed before and after each structure was removed. Because the path was identical in each test, the principle of superposition was applied. Thus, the difference between the resultant forces could be attributed to the force carried by the structure just removed. The magnitudes of force in the ACL at 30 degrees and 90 degrees of knee flexion were 114.1 +/- 7.4 N and 90.8 +/- 8.3 N, respectively (P < 0.05). At 30 degrees, the AM and PL bundles carried 95% and 4% of the total ACL force, respectively. At 90 degrees, the AM and PL bands carried 85% and 13%, respectively (P < 0.05). The direction of the in situ force in the whole ACL as well as its two bands correlated with the anatomic orientation of the ligament.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1995

Regulation of IGF binding proteins by FSH in human luteinizing granulosa cells.

OBJECTIVE: To evaluate the regulation of the secretion of insulin-like growth factor (IGF) binding proteins (IGFBPs) by FSH in human luteinizing granulosa cells. DESIGN AND RESULTS: Luteinizing granulosa cells were incubated with and without FSH. Levels of IGFBP-1 and -3 in the medium were measured by EIA and RIA, respectively and binding activities of these IGFBP were evaluated by Western ligand blot. FSH inhibited the secretion of IGFBP-1 dose dependently. FSH did not inhibit the secretion of immunoreactive IGFBP-3, but inhibited the binding activity of IGFBP-3. To assess the protease activity, 125I-IGFBP-3 was incubated with the cultured medium. 125I-IGFBP-3 degraded into small fragments when it was incubated with the cultured medium treated with FSH. CONCLUSIONS: FSH enhances the action of IGF-I in human granulosa cells by inhibiting the secretion of IGFBP-1 and the binding activity of IGFBP-3 by stimulating the proteolysis of IGFBP-3.

Blotting, Western↗
PubMed1995

The fetal central venous pressure waveform in normal pregnancy and in umbilical placental insufficiency.

OBJECTIVE: Our purpose was to study the fetal central venous pressure waveform recorded noninvasively from the inferior vena cava in normal and complicated pregnancies by means of newly developed equipment to follow the vessel lumen diameter. STUDY DESIGN: A paired ultrasonic phase-locked loop echo tracking system with a high sampling frequency (3000 Hz) was used to follow the movement (point displacement) of diametrically opposite points of the vessel wall. The lumen was measured as the interval between these points. We studied 70 normal fetuses (20 to 40 weeks) and 54 complicated pregnancies with increased umbilical placental resistance. RESULTS: The four component waves of the central venous pressure waveform (A, X, V, Y) were identified and measured in the fetal recording. The crests of the A and V waves were of approximately equal height. An increase in the descent of the Y trough was observed with advancing gestation. By means of data from the normal group, the complicated group was divided into three subgroups. In 10 fetuses the waveform was normal. In 31 there was a high pulsatile pattern with deep descent from the A crest to X trough so that the pulsatility of the waveform appeared increased. In 13 this was shallow and the pulsatility appeared reduced. Clinical outcome (nonreactive fetal heart rate, percentile birth weight, days in neonatal intensive care unit) was significantly worse in both these latter two subgroups in comparison with normal and in the low compared with the high-pulsatile group. CONCLUSIONS: Human fetal central venous pressure waveforms can be simply recorded and represented by the transluminal diameter waveform. In fetal compromise the high pulsatility waveform may result from a reduced ventricular ejection and increased end-diastolic pressure in response to the increase in ventricular afterload caused by the placental vessel obliteration. In the most profoundly compromised fetuses the low pulsatility waveform may indicate depressed myocardial function and output.

Central Venous Pressure↗
PubMed1995

Iridoid glucosides from the leaves and stems of Duranta erecta.

From the leaves of Duranta erecta, four new iridoid glucosides, duranterectosides A, B, C and D, were isolated along with durantosides I and II, lamiide, lamiidoside and verbascoside. Duranterectoside A was also isolated from the stems together with durantosides I, II and III, and lamiidoside. The structures of the new compounds were elucidated based on the spectroscopic evidence.

Carbohydrate Conformation↗
PubMed1995

Aldosterone biosynthesis and action in vascular cells.

In view of the hypothetical possibility that the vascular renin-angiotensin system (RAS) might include aldosterone biosynthesis and action in the vasculature, we have undertaken a study to identify aldosterone released into the perfusion circuit from the rat mesenteric artery, and to investigate the effects of an angiotensin converting enzyme inhibition (ACEI) on aldosterone production from the vasculature. After 30 min equilibration, 240 mL of perfusate was collected and subjected to reverse-phase HPLC and subsequent mass spectrometry. Mass spectra corresponding to authentic corticosterone and aldosterone were obtained from the samples of mesenteric artery perfusate. Production of aldosterone in the mesenteric artery was not changed by adrenalectomy, although it was reduced in the arterial perfusate from rats pretreated with ACEI. By RT-PCR the expression of CYP 11B2 and mineralocorticoid receptor genes were demonstrated in both vascular endothelial and smooth muscle cells. These studies constitute indirect evidence supporting our hypothesis that locally produced aldosterone in the vascular tissue acts on vascular tone and remodeling via a paracrine or autocrine manner.

Aldosterone↗
PubMed1995

Significance of 19-noraldosterone, a new mineralocorticoid, in clinical and experimental hypertension.

19-Noraldosterone, which was recently shown to be synthesized and produced in the human adrenal gland, possesses potent mineralocorticoid and hypertensinogenic activities. 18,19-Dihydroxycorticosterone (18,19-(OH)2-B) and 18-hydroxy-19-norcorticosterone (18-OH-19-nor-B), a possible precursor of 19-noraldosterone, have been identified in human urine. These mineralocorticoid hormones are regulated by the renin-angiotensin system and synthesized in adrenal glomerulosa cells. Urinary 19-noraldosterone correlated with urinary 18,19-(OH)2-B, 18-OH-19-nor-B, 18-hydroxycorticosterone (18-OH-B), and aldosterone. Urinary excretion of 19-noraldosterone, 18,19-(OH)2-B, and 18-OH-19-nor-B were increased in patients with aldosterone-producing adenoma (APA) and in those with idiopathic hyperaldosteronism (IHA), but the two did not differ significantly. Urinary 18-OH-B and 18-hydroxycortisol (18-OH-F) were significantly higher in APA compared with IHA. Though urinary 18-OH-F and 18-OH-B concentrations were useful markers, urinary 19-noraldosterone, 18,19-(OH)2-B, and 18-OH-19-nor-B could not be used to distinguish the two subsets of primary aldosteronism. Urinary 19-noraldosterone did not differ in hypertensive and normotensive patients. However, urinary 19-noraldosterone was increased in some hypertensive patients. In spontaneously hypertensive rats (SHR) and stroke-prone SHR (SHRSP), urinary 19-noraldosterone was increased at the prehypertensive stage compared with Wistar-Kyoto (WKY) rats. Urinary 19-noraldosterone was decreased in 9-week-old SHR and SHRSP compared with WKY rats. However urinary 19-noraldosterone was higher in SHRSP than in SHR. These elevated levels of 19-noraldosterone may contribute to hypertension in some individuals and in experimental hypertensive rats.

Aldosterone↗
PubMed1995

Erythroid differentiation and growth inhibition of K562 cells by 2',5'-dideoxyadenosine: synergism with interferon-alpha.

We found that 2',5'-dideoxyadenosine (DDA), a P-site specific adenylate cyclase inhibitor, inhibited the growth of K562 cells and caused them to become benzidine positive. The continuous exposure of cells to DDA was needed to recruit cells for growth inhibition and differentiation. Fetal calf or human sera were also necessary for DDA to induce differentiation. DDA at a concentration of 1.5 mM with serum induced 98% of the cells to produce hemoglobin and inhibited their growth to 15% of that of the control. An increase of epsilon-globin mRNA and a decrease of c-myc and c-myb mRNA occurred only during differentiation in the presence of fetal calf serum (FCS). An incubation with DDA and interferon-alpha (IFN-alpha) or hemin synergistically induced more benzidine-positive cells than in the presence of DDA alone, although IFN-alpha did not trigger differentiation by itself. The erythroid differentiation and growth inhibition were, however, not related to a decreased intracellular cyclic AMP (cAMP) concentration induced by DDA. The simultaneous incubation with dibutyryl cyclic AMP (dbc-AMP) and DDA enhanced the effects of DDA. Adenine, a possible metabolite of DDA digestion by purine nucleoside phosphorylase (PNP), also induced erythroid differentiation in K562 cells. However, it did not act synergistically with IFN-alpha.

Adenine↗