Search PubMed⌕ Search

Biomedical subjects

K Sugimoto

Publications and source records attributed to K Sugimoto.

At least 379 records · Page 21Linked to original sources
PubMed1994

Functional cloning of centromere protein B (CENP-B) box-enriched alphoid DNA repeats utilizing the sequence-specific DNA binding activity of human CENP-B in vitro.

The centromere is a distinctive portion of the chromosome consisting of 'centromere DNA' and 'centromere proteins'. Recently, a direct molecular interaction was discovered between human centromere protein B (CENP-B) and human centromeric alphoid repeats. This enabled us to isolate the CENP-B-targeted centromeric DNA sequences by positively utilizing the biologic activity of CENP-B in vitro. In the previous model experiment, we found that oligonucleotides covering the CENP-B binding sequences were enriched by the DNA immunoprecipitation procedure. Here we apply the same technique to the direct isolation of a functional part of human centromeric DNA from a genomic DNA library. Restriction digestion of two isolated clones showed the typical repeating pattern of an alphoid family that is known to localize at the centromeric region of all human chromosomes. Sequence analysis showed that these two clones frequently contain the authentic CENP-B binding motif, CTTCGTTGGAAACGGGA, or a new one with one base replaced, CTTCGTTGGAAACGGGT. The frequent distribution of these motifs suggests that the isolated sequences are directly involved in the organization of centromeric heterochromatin at the primary constriction in conjunction with CENP-B.

Autoantigens↗
PubMed1994

The role of angiography in the assessment of blunt liver injury.

Angiography and therapeutic embolism (TE) were studied retrospectively in cases of blunt liver injury with regard to their indications and usefulness. The management of patients fell into three groups distinguished by the clinical evidence of the severity of the liver injuries. The most severe 42 cases (39.6 per cent) were managed surgically and promptly, the least severe 38 cases were not subjected to angiography and the intermediate group (26 cases; 24.5 per cent) underwent angiography and 12/26 cases underwent TE. However, haemodynamic stability on admission was not significantly different between these groups. In addition, all patients who underwent angiography and TE had more severe parenchymal injury on imaging studies while their haemodynamic instability was not identified on admission. Angiography and TE for blunt liver injury were most strongly indicated in patients with good haemodynamic responses to intravenous fluid administration during the acute phase and/or in cases of severe parenchymal injury on imaging.

Algorithms↗
PubMed1994

Age-related decreases in the reconstituting ability of hemopoietic cells and the ability of hemopoietic microenvironment to support hemopoietic reconstitution in senescence accelerated (SAM-P) mice.

The effect of the aging process on the hemopoietic system in senescence-accelerated (SAM-P) mice with respect to the reconstituting ability of hemopoietic cells and the ability of the microenvironment to support hemopoietic reconstitution was investigated by bone marrow transplantation (reconstitution assay). When the bone marrow cells, obtained from young or old mice, were transplanted to lethally irradiated young SAM-P mice no difference in the reconstituting pattern of femoral spleen colony-forming units (CFU-S), splenic CFU-S and splenic granulocyte macrophage colony-forming units (CFU-GM) was observed between the mice transplanted with young and old donor cells. However, the reconstitution of femoral CFU-GM in mice transplanted with old donor cells was delayed compared to that in mice transplanted with young donor cells. Moreover, the recovery of WBC in mice transplanted with old donor cells was noticeably delayed. When the bone marrow cells obtained from young mice were transplanted to young or old recipient mice, no difference in the reconstituting pattern of femoral CFU-S and CFU-GM as well as splenic CFU-S and CPU-GM was observed between young and old recipient mice. However, the recovery of WBC in old recipient mice was noticeably delayed. These data indicate that the functions of both the hemopoietic cells and the hemopoietic microenvironment deteriorated with age in SAM-P mice.

Aging↗
PubMed1994

Constitutive production of IL-6 in the anemic mice of W/Wv genotype.

IL-6 was found to be produced by bone marrow cell fraction enriched for hemopoietic stem cells in response to IL-3 stimulation. To confirm the production of IL-6 by hemopoietic stem cells, we studied the response of W/Wv mouse bone marrow cells to IL-3 stimulation in terms of IL-6 production. Genetically anemic mice of W/Wv genotype are known to be depleted of normal hemopoietic stem cells. Bone marrow cells of W/Wv mice produce IL-6 without IL-3 stimulation. But bone marrow cells of the litter mate (+/+) mice studied as controls do not produce IL-6 without stimulation. IL-3 induced the production of IL-6, GM-CSF and G-CSF from the bone marrow cells of +/+ mice. Gene expression of IL-6, GM-CSF, G-CSF and IL-3 in these mice was detected in total bone marrow cells after IL-3 stimulation. In contrast, bone marrow cells of C3H mice did not produce IL-3 even after IL-3 stimulation. Bone marrow cells of C3H mice reportedly produce a diffusible IL-3 inhibitor (NIL-3), but those of C57BL mice do not. Present findings indicate the strain-dependent differences in hemopoietic stimulating factor production. The constitutive IL-6 production in W/Wv mice might be due to a constant and strong demand for blood cell production of the anemic mice.

Anemia↗
PubMed1994

Evidence that glutamate is released from capsaicin-sensitive primary afferent fibers in rats: study with on-line continuous monitoring of glutamate.

The aim of this study is to elucidate whether the excitatory amino acid glutamate is released from capsaicin-sensitive primary afferent fibers, and to compare the releasing effect of capsaicin on glutamate with that on substance P. The release of glutamate was measured using a fluorometric on-line continuous monitoring system, in which the immobilized glutamate dehydrogenase column was connected to an in vitro superfusion system. In the presence of 0.3 microM tetrodotoxin, 2-min application of capsaicin produced an increased outflow of glutamate, as well as an increase in the release of immunoreactive substance P from dorsal horn slices of the rat. The release of glutamate was concentration-dependently increased by capsaicin at concentrations in the range of 0.1-3 microM, and the release evoked by 10 microM capsaicin was not higher than that evoked by 3 microM. On the other hand, capsaicin at concentrations of 1-10 microM produced a concentration-dependent increase in the release of immunoreactive substance P, without effect at 0.1 microM. The amount of glutamate release evoked by 3 microM capsaicin was about 42.8 pmol.mg-1 protein, and 290 times that of immunoreactive substance P. The release of glutamate by 3 microM capsaicin was suppressed by the depletion of calcium from the superfusate. Capsaicin at 3 microM failed to increase the release of glutamate from the dorsal horn slices of the rats made an L4-L6 dorsal rhizotomy. These results suggest that capsaicin evoked the release of glutamate from primary afferent fibers in the dorsal horn and that glutamate may play an important role in pain transmission between primary afferent fibers and dorsal horn neurons.

Animals↗
PubMed1994

Inverse relationships between cell proliferation and basal or androgen-stimulated apolipoprotein D secretion in LNCaP human prostate cancer cells.

We have recently demonstrated that the biphasic action of androgens on LNCaP cell proliferation is opposite to their effect on apolipoprotein D (apo-D) secretion, the stimulation of apo-D secretion being associated with a steroid-induced inhibition of cell proliferation. To further characterize the control of apo-D expression in LNCaP cells, we studied basal as well as androgen-induced apo-D secretion in slowly proliferating, low-passage (LP; 20-29th) and rapidly proliferating high-passage (HP; 111-117th) cell cultures. For comparison, the androgen-induced stimulation of prostate specific antigen secretion was also investigated in LP and HP cell cultures. In the absence of androgens, basal cell proliferation of HP cells was significantly higher than that of LP cells, whereas apo-D secretion was higher in LP cells than in HP cells. Furthermore, the biphasic action of dihydrotestosterone and of the synthetic androgenic compound R1881 on apo-D release and cell proliferation was observed in both LP and HP cells. The stimulation of apo-D secretion was inversely related to that of cell proliferation and influenced by cell density. The inhibition of basal and androgen-induced cell proliferation by the calcium channel blocker nifedipine was also associated with an increase in apo-D secretion. The amount of PSA released and the sensitivity of its response to R1881 were increased in LP cells compared with HP cells. The present study thus demonstrates, for the first time, that apo-D secretion is inversely correlated to cell proliferation and cell density in the absence as well as in the presence of androgens in both LP and HP LNCaP human prostate cancer cells. This finding suggests that apo-D expression can be modulated not only by steroid hormones, but also by other factors involved in the control of cell proliferation.

Apolipoproteins↗
PubMed1994

The Cognitive Abilities Screening Instrument (CASI): a practical test for cross-cultural epidemiological studies of dementia.

The Cognitive Abilities Screening Instrument (CASI) has a score range of 0 to 100 and provides quantitative assessment on attention, concentration, orientation, short-term memory, long-term memory, language abilities, visual construction, list-generating fluency, abstraction, and judgment. Scores of the Mini-Mental State Examination, the Modified Mini-Mental State Test, and the Hasegawa Dementia Screening Scale can also be estimated from subsets of the CASI items. Pilot testing conducted in Japan and in the United States has demonstrated its cross-cultural applicability and its usefulness in screening for dementia, in monitoring disease progression, and in providing profiles of cognitive impairment. Typical administration time is 15 to 20 minutes. Record form, manual, videotape of test administration, and quizzes to qualify potential users on the administration and scoring of the CASI are available upon request.

Aged↗
PubMed1994

Transposition of the maize Ds element from a viral vector to the rice genome.

The geminivirus miscanthus streak virus (MiSV) was used as a gene vector to study the transposition of the maize Ds element in rice protoplasts. Efficient excision of the Ds from the MiSV vector was observed only when the MiSV vector was allowed to replicate and the plasmid expressing the transposase gene encoded by Ac was co-transfected. Under the same condition, the Ds carrying a hygromycin phosphotransferase gene (Ds::HPT) was also efficiently excised. Hygromycin-resistant calli were obtained by culturing these transfected protoplasts in order to examine the transposition of the excised Ds::HPT into the rice genome. In five out of 16 calli examined, the Ds::HPT, but not the vector sequence, was integrated into the rice genome and 8 bp target site duplication typical of Ac/Ds transposition was generated. These results show that the Ds::HPT inserted in the MiSV vector transposed directly into the rice genome. This demonstrates the direct transposition of a cloned plant transposable element into the plant genome. Implications of these finding are discussed.

Base Sequence↗
PubMed1994

Human centromere protein C (CENP-C) is a DNA-binding protein which possesses a novel DNA-binding motif.

Mammalian centromere proteins (CENPs) can be divided into those that translocate from centromere to midzone in the progress of mitosis, and those that remain at the centromere throughout the cell cycle. The latter including CENP-A, CENP-B, and CENP-C is the candidate for DNA-binding protein. CENP-B has been shown previously to possess the specific DNA-binding activity to 17-base pair sequences dispersed on human centromeric alphoid repeats. In this study, we examined DNA-binding property of CENP-C that is localized to inner kinetochore plate of the metaphase chromosome. We independently isolated a full-length cDNA encoding human CENP-C and expressed it as the polypeptide tagged with histidine oligomer in Escherichia coli. After affinity purification with Ni(2+)-chelated resin, DNA-binding activity of the recombinant CENP-C renatured on the membrane was demonstrated by using human genomic DNA and an alphoid subfamily in South-Western-type blotting analysis. By constructing a series of truncated products, the DNA-binding domain was located at an internal 101-amino-acid stretch with no apparent homology to any other DNA-binding proteins. This may suggest that CENP-C is directly involved in formation of kinetochore chromatin fibers.

Amino Acid Sequence↗
PubMed1994

The Glc7 type 1 protein phosphatase of Saccharomyces cerevisiae is required for cell cycle progression in G2/M.

We isolated a mutant carrying a conditional mutation in the GLC7 gene, encoding the catalytic subunit of a type 1 protein phosphatase, by selection of suppressors that restored the growth defect of cdc24 mutants at high temperature and simultaneously conferred cold-sensitive growth. This cold sensitivity for growth is caused by a single mutation (glc7Y-170) at position 170 of the Glc7 protein, resulting in replacement of cysteine with tyrosine. Genetic analysis suggested that the glc7Y-170 allele is associated with a recessive negative phenotype, reducing the activity of Glc7 in the cell. The glc7Y-170 mutant missegregated chromosome III at the permissive temperature, arrested growth as large-budded cells at the restrictive temperature, exhibited a significant increase in the number of nuclei at or in the neck, and had a short spindle. Furthermore, the glc7Y-170 mutant exhibited a high level of CDC28-dependent protein kinase activity when incubated at the restrictive temperature. These findings suggest that the glc7Y-170 mutation is defective in the G2/M phase of the cell cycle. Thus, type 1 protein phosphatase in Saccharomyces cerevisiae is essential for the G2/M transition.

Amino Acid Sequence↗
PubMed1994

Effects of hypertension and aging on fibronectin expression in aorta of Dahl salt-sensitive rats.

Effects of hypertension and aging on aortic fibronectin expression were investigated in male Dahl salt-sensitive (Dahl-S) and salt-resistant (Dahl-R) rats fed either a low- or high-salt diet from 5 to 37 wk of age. In comparison to low-salt controls, the steady-state mRNA levels for aortic fibronectin in salt-loaded Dahl-S rats were dramatically increased at 37 wk of age, corresponding to a severe stage of hypertension with high mortality, whereas at earlier ages representing early to established phases of hypertension, no significant changes were observed. Salt loading affected neither blood pressure nor aortic fibronectin expression in Dahl-R rats. Aging without coexisting hypertension did not cause significant changes in aortic fibronectin mRNA levels all through the study period in either strain of rats. These results suggest that aortic fibronectin may be strongly regulated by factors associated with severe hypertensive organ damages caused by long-standing hypertension in salt-loaded Dahl-S rats. Also suggested was that aortic fibronectin may not play a major role in the pathogenesis of early aortic changes occurring in response to hypertension or as a process of aging.

Aging↗
PubMed1994

Effects of B subunit of cholera toxin on histamine release from rat peritoneal mast cells.

We studied the effects of B subunit of cholera toxin (CTB) on secretagogue-induced histamine release from rat peritoneal mast cells. CTB inhibited the release of histamine in response to compound 48/80, but not in response to mastoparan, substance P, concanavalin A or ionophore A23187. The results suggest that CTB can be used as a tool for studying the cellular events involved in histamine release from mast cells.

Animals↗
PubMed1994

Mechanism of periodic breathing in patients with cardiovascular disease.

Although periodic breathing consisting of alternating hyperpnea and hypopnea has been recognized in heart failure patients, its mechanism has not been clarified. We hypothesized that heart failure patients who have oscillations in ventilation will also be found to have oscillations in pulmonary blood flow, as reflected in left ventricular ejection fraction. To test this hypothesis, we analyzed continuously gas exchange and left ventricular ejection fraction during exercise in cardiac patients who exhibited periodic breathing. Out of 48 consecutive patients with reduced left ventricular function who performed a symptom-limited incremental exercise test using an upright cycle ergometer, we selected 5 patients who exhibited clear ventilatory oscillations during exercise. These patients repeated the same exercise test on another day for measuring gas exchange and left ventricular ejection fraction continuously. Oscillatory changes were noted both in left ventricular ejection fraction and in ventilation in these patients. These observations offer support for the hypothesis that fluctuations in pulmonary blood flow are primarily responsible for the periodic breathing seen in heart failure patients.

Aged↗
PubMed1994

Induction of granulocyte-macrophage colony-stimulating factor (GM-CSF) and granulocyte colony-stimulating factor (G-CSF) expression in bone marrow and fractionated marrow cell populations by interleukin 3 (IL-3): IL-3-mediated positive feedback mechanisms of granulopoiesis.

Interleukin 3 (IL-3) induces proliferation and differentiation of mast cell progenitors in vitro, whereas it induces granulocytosis in vivo. In this paper, a positive feedback mechanism of granulopoiesis was studied in order to elucidate the granulocytosis induced by IL-3 in mouse. IL-3 induced expression of granulocyte-macrophage colony-stimulating factor (GM-CSF) and granulocyte colony-stimulating factor (G-CSF) in total bone marrow cells and a marrow adherent cell population. In fractionated marrow cell populations, a different expression pattern of induction of IL-3 stimulation was observed; GM-CSF was expressed in macrophages and fraction 1 (P < 1.061) and 2(1.061 < P 1.074) of bone marrow cells fractionated by equilibrium density centrifugation, G-CSF was expressed in macrophages and fraction 2 and 3 (1.074 < P < 1.097), and interleukin 6 (IL-6) in macrophages and fraction 1 to 3. These results indicate a hierarchical regulation of cytokine production and the existence of a positive feedback mechanism in granulopoiesis. IL-6, induced by IL-3, stimulates stem cells into cycle and induces stem cells to respond to IL-3. The stem cells differentiate to granulocyte-macrophage colony-forming cells by the combined effect of IL-3 and IL-6. IL-3 also induces GM- and G-CSF expression which in turn makes granulocyte-macrophage colony-forming cells differentiate to granulocytes. These factors organize a cytokine network in granulopoiesis.

Animals↗
PubMed1994

[Successful collection of peripheral blood stem cells mobilized by high-dose etoposide for patients with chemotherapy-resistant and/or poor prognostic testicular cancer].

Clinical effects of peripheral blood stem cell autotransplantation (PBSCT) after ultra high-dose chemotherapy were evaluated in patients with chemotherapy-resistant and/or poor prognostic testicular cancer. Four patients with testicular cancer, who had high-risk malignancy, were treated with high-dose etoposide (500 mg/m2 x 4 days) in order to collect peripheral blood stem cells. After the administration of high-dose etoposide, rG-CSF (250 micrograms/body) was administered from nadir state. Blood mononuclear cells were collected using a Fenwall CS-3000 blood cell separator. Fractions enriched for stem cells were obtained by discontinuous Percoll gradient centrifugation and were stored in liquid nitrogen using patient's sera and DMSO. The mean number of peripheral blood granulocyte-macrophage-colony-forming units (CFU-GM) collected by one apheresis was 22.3 x 10(5)/kg body weight. In addition, CFU-GM more than 2.0 x 10(5)/kg body weight could be collected in each apheresis, which was though to be sufficient dosis to perform PBSCT in safe, based upon our previous studies. All the patients were treated by a combination of cisplatin (20 mg/m2 x 5 days), etoposide (100 mg/m2 x 5 days) and bleomycin (15 mg x 3 days). Three patients responded to BEP therapy and obtained a CR, however, remaining 1 patient failed to achieve CR, who was later treated by ultrahigh-dose chemotherapy including carboplatin (200 mg/m2 x 4 days), etoposide (250 mg/m2 x 4 days) and cyclophosphamide (50 mg/kg x 2 days) followed by PBSCT. He responded to this therapy and obtained a CR for 10 months. The results suggested the method was promising for patients with chemotherapy-resistant and/or poor prognostic testicular cancer.

Adult↗
PubMed1994

[Effect of verapamil on adriamycin resistant bladder tumor cells].

RBT-K5 cell line was established from a male Wistar rat bladder tumor induced with N-butyl-N-(4-hydroxybutyl) nitrosamine. RBT-K5 (ADM res.) cell line, adriamycin (ADM) resistant, was also established from RBT-K5 cells by stepwise escalation of ADM concentrations in vitro. In this study, we have examined the effect of verapamil (VR) on intracellular ADM concentration in these cell lines. The viability of RBT-K5 cells was significantly lower than that of RBT-K5 (ADM res.) at the concentration from 0.5 to 4 micrograms/ml of ADM. The cytotoxic effect of ADM was enhanced by the addition of VR in the both cell lines. The intracellular ADM concentrations of RBT-K5 and RBT-K5 (ADM res.) were increased from 607.7 +/- 74.1 ng/10(6) cells to 1152.1 +/- 187.6 ng/10(6) cells (1.9-fold) and from 185.1 +/- 36.5 ng/10(6) cells to 751.5 +/- 258.4 ng/10(6) cells (4.1-fold), respectively, 24 hours after incubation in the presence of 10 micrograms/ml of VR. Furthermore, the intracellular ADM concentration was maintained at high-level in combination with VR even after the removal of ADM from culture medium. These results suggest that the combination therapy with VR is more effective against ADM-resistant than ADM-sensitive bladder tumor.

Animals↗
PubMed1994

[Ultra high-dose chemotherapy with peripheral blood stem cell autotransplantation for refractory testicular cancer].

This is a report of 45-year-old man with advanced nonseminomatous germ cell tumor (stage IIIB2: embryonal carcinoma, yolk sac tumor, seminoma), who had relapse after PVB (cisplatin, vinblastine, bleomycin) chemotherapy. Peripheral blood stem cells (PBSCs) were taken by two consecutive apheresis using a CS-3000 blood separator after high-dose chemotherapy of cytarabine and mitoxantrone. In total, 6.4 x 10(5)/kg of granulocytic cells (CFU-GM) was collected. He was treated with ultra high-dose chemotherapy consisting of carboplatin (800 mg/m2), etoposide (1,000 mg/m2) and cyclophosphamide (100 mg/kg) from day 1, followed by peripheral blood stem cell autotransplantation (PBSCT) on day 9. We transfused 2.4 x 10(5)/kg CFU-GM, which was enough number of stem cells for safe PBSCT. No serious side effects or complications were encountered. The patient achieved partial remission for more than two months. However, he died of respiratory dysfunction caused by metastatic lung cancer 5 months later. It was thought that ultra high-dose chemotherapy with PBSCT might be a new therapy for refractory testicular cancer.

Antineoplastic Combined Chemotherapy Protocols↗