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Biomedical subjects

N Nishi

Publications and source records attributed to N Nishi.

At least 109 records · Page 6Linked to original sources
PubMed1992

Primary structures of sardaines Z1 and Z2, protamines isolated from striped bonito (Sarda orientalis).

Striped bonito protamine, sardaine, was isolated from the sperm of striped bonito (Sarda orientalis) by extraction with sulfuric acid followed by ion-exchange chromatography. The preparation gave a single band upon polyacrylamide gel electrophoresis. Sardaine consists of 34 amino acid residues, and its sequence is: Pro-Arg-Arg-Arg-Arg-Arg-Ser(Ala)-Ser-Arg-Pro-Val-Arg-Arg-Arg-Arg-Arg-Tyr -Arg- Arg-Ser-Thr-Ala-Ala-Arg-Arg-Arg-Arg-Arg-Val-Val-Arg-Arg-Arg-Arg. At position 7, serine (sardaine Z1) is partially replaced by alanine (sardaine Z2). The ion spray mass spectrum shows that sardaines Z1 and Z2 have molecular masses of 4,612.49 and 4,596.09 Da, respectively. The sequence of sardaine Z1 is 100% identical with that of thynnine Z2 from tuna fish (both fish belong to Scombridae, Perciformes).

Amino Acid Sequence↗
PubMed1991

Rat prostatic growth factors: purification and characterization of high and low molecular weight epidermal growth factors from rat dorsolateral prostate.

Growth factors which possibly participate in androgen-induced proliferation of rat prostate epithelial cells have been purified and characterized. Four distinct forms of growth factor were found in the extract of rat dorsolateral prostate. One of the factors was a member of heparin-binding growth factor (HBGF) family judging from its high affinity for heparin-Sepharose. The other three factors were capable of competing with [125I]epidermal growth factor (EGF) for the cell surface receptor, and recognized by anti-rat EGF antiserum. These EGF-like factors (EGF1-EGF3) were purified by ion-exchange chromatography, gel filtration and reverse phase HPLC. EGF1 showed microheterogeneity on chromatographic and electrophoretic separation and N-terminal sequence analysis. EGF1 showed an average molecular weight of about 35,000 on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) under reducing conditions. These results indicated that EGF1 was a mixture of high molecular weight forms of EGF. The molecular weights of EGF2 and EGF3 were similar to that of rat submaxillary gland EGF (Mr = 5400). The amino acid sequence of EGF2 was identical with that of rat EGF except for the N- and C-terminal amino acids: aspartic acid instead of asparagine was found at the N-terminal position and C-terminal arginine was missing in EGF2. Although the N-terminal sequence of EGF3 (1-19) was identical with that of EGF2, the two factors were completely separated by gel filtration indicating a difference in the C-terminal structure. EGF1, EGF2 and EGF3 but not HBGF stimulated proliferation of primary cultured rat dorsolateral prostate epithelial cells.

Amino Acid Sequence↗
PubMed1991

Actin polymerization promoted by a heptapeptide, an analog of the actin-binding S site on myosin head.

Polymerization of G-actin to F-actin was indicated by an increase in light-scattering intensity after the addition of a heptapeptide (Ile-Arg-Ile-Cys(MT)-Arg-Lys-Gly-OEt), an analog of the actin-binding S-site on S-1 heavy chain. The half-maximal concentration of the heptapeptide which induced an increase in the light-scattering intensity at 25 degrees C was about 110 microM, which was in the range of the dissociation constant of this peptide with F-actin. The polymerization of G-actin to F-actin by binding of the heptapeptide was further demonstrated by ultracentrifugal separation, Pi liberation, and electron microscopy. The polymerization of G-actin was induced only by the heptapeptide, but not by fragments of the heptapeptide. The well known acceleration of polymerization of G-actin by the myosin head may be due to the binding of G-actin with the S-site on the myosin head.

Actins↗
PubMed1991

Role of cyclic AMP and polypeptide growth regulators in growth inhibition by interferon in PC-3 cells.

Participation of growth factors and intracellular cAMP in direct antiproliferative action of interferon alpha (IFN-alpha) was investigated in PC-3 human prostate carcinoma cell line. IFN-alpha inhibited proliferation of PC-3 cells in a dose-dependent manner in vitro, and the effect was reversible. Fibroblast growth factor, epidermal growth factor and platelet-derived growth factor, when added to the culture medium, showed no effect on growth of PC-3 cells in presence or absence of IFN-alpha. Transforming growth factor beta (TGF-beta) significantly inhibited PC-3 cell growth, and the effect was additived to that of IFN-alpha. TGF-beta content in conditioned medium of PC-3 cells was not affected by treatment with IFN-alpha. On the other hand, IFN-alpha increased intracellular cAMP concentration about 20-fold. Dibutyryl cAMP and reagents which elevated intracellular cAMP level also inhibited PC-3 cell growth. These indicated that direct antiproliferative effect of IFN-alpha on PC-3 cells was at least partly mediated by cAMP, and that neither growth factors nor a growth inhibitor participated in the action of IFN-alpha.

Alprostadil↗
PubMed1991

Hydration of clupeine in solution.

Spin-lattice relaxation times, T1, of H2(17) O at 25 degrees were measured for aqueous solutions of clupeine and its constituent amino acids, which are serine, threonine, proline and arginine. The dynamic hydration numbers, nDHN, of clupeine and amino acids were determined from a concentration dependence of T1. The coordination numbers nh, and the rotational correlation times, tau ch, of water molecules around clupeine and amino acids were estimated and compared with that of pure water. The tau ch/tau co of clupeine was 1.85 and close to that of arginine. The experimental value of nDHN of clupeine was in good agreement with that calculated from the nDHN values of the constituent amino acids. This means that the clupeine molecule has a random conformation in solution.

Amino Acid Sequence↗
PubMed1991

Molecular properties of poly(RGD) and its binding capacities to metastatic melanoma cells.

We examined the binding capacity of anti-metastatic polypeptide containing repetitive Arg-Gly-Asp(RGD) sequence derived from cell binding site of fibronectin, poly(RGD), to the surface of tumor cells. Poly(RGD) competitively inhibited the binding of radiolabeled fibronectin to the cell surface more potently than oligo(RGD) or RGD tripeptide on a molar basis. Compared on a weight basis to oligo(RGD) or RGD peptide, poly(RGD) was more active than the oligo- and monomeric peptide at inhibiting tumor cell adhesion to immobilized fibronectin. The secondary structure of poly(RGD) was predicted to be a beta-turn from the data of CD spectra and its amino acid sequence. These findings suggest that poly(RGD)-mediated inhibition of cell adhesion is due to its potent binding capacity to fibronectin receptors on cell surface probably through its conformational properties.

Animals↗
PubMed1991

Reproductive and developmental toxicity studies on catena-(S)-[mu-[N alpha-(3-aminopropionyl) histidinato(2-)-N1,N2,O:N tau]-zinc].

To evaluate the effects of Z-103 (catena-(S)-[mu-[N alpha-(3-aminopropionyl) histidinato (2-)-N1,N2,O:N tau]-zinc], CAS 107667-60-7) on the reproductive performance of male and female rats, the general toxicity of dams, and the development, physical growth and reproductive performance of the next generation, Z-103 was administered to rats prior to, and in the early stages of pregnancy, during the period of fetal organogenesis, and during the perinatal and lactation periods, and to rabbits during the period of fetal organogenesis at the appropriate doses for each study. At the administration of Z-103 prior to and in the early stages of pregnancy in rats, no dose-related abnormalities were observed in the reproductive performance of either sex. Furthermore, there were no death or evidence of teratogenicity or repressive effect on growth in fetuses. Administration of Z-103 during the period of fetal organogenesis in rats affected the growth of embryos and fetuses at 1200 mg/kg. At 600 mg/kg or less, however, there were no death, teratogenicity or repressive effect on growth in fetuses, and furthermore, no dose-related abnormalities were observed in growth, physical development, behavior and reproductive performance in offspring. Administration of Z-103 during the period of fetal organogenesis in rabbits caused a decrease in the number of live fetuses at 300 mg/kg suggesting that 300 mg/kg of Z-103 may have a lethal effect on fetuses. There were, however, neither teratogenicity nor any repressive effect on the growth of fetuses.(ABSTRACT TRUNCATED AT 250 WORDS)

Abnormalities, Drug-Induced↗
PubMed1990

Induction of mixed erythroid-megakaryocyte colonies and bipotential blast cell colonies by recombinant human erythropoietin in serum-free culture.

The effects of recombinant human erythropoietin (rEp) on murine hematopoietic progenitors were studied using a serum-free culture. A high concentration of rEp stimulated the formation of mixed erythroid-megakaryocyte colonies (EM colonies) and blast cell colonies, as well as erythroid colonies, erythroid bursts, and megakaryocyte colonies from normal mouse bone marrow cells. Direct effects of rEp on EM colony, megakaryocyte colony, and erythroid burst formation were confirmed by depletion of accessory cells such as T cells, B cells, and macrophages from crude bone marrow cells, and inhibition of the colonies by the addition of rabbit anti-rEp antibody to the culture in a dose-dependent fashion. Replating experiments were performed to confirm the differentiating ability of blast cell colonies grown in the presence of rEp. Most of the blast cell colonies yielded not only secondary erythroid colonies but also megakaryocyte colonies in the presence of 2 IU/mL rEp. Some of the blast cell colonies produced secondary EM colonies in the presence of 16 IU/ml rEp of 2 IU/mL rEp plus interleukin-3, although no granulocyte-macrophage colonies were found in the secondary culture. These results suggest that Ep acts not only as a late-acting factor that is specific for erythroid progenitors, but also as a bipotential EM-stimulating factor for murine hematopoietic cells.

Animals↗
PubMed1990

Purification and identification of a growth factor produced by Paramecium tetraurelia.

We previously reported that the jumyo mutant of a cilate protozoan Paramecium tetraurelia excretes into the medium a factor which promotes its own cell division. Here, the factor was purified to electrophoretic homogeneity through a series of liquid chromatographic procedures. This substance is a protein with a molecular weight of 17,000 which at concentrations of 1 X 10(-9) M (17 ng/ml) or more results in the recovery of the cell division rate of the jumyo mutant to the level of the wild type. The factor is therefore considered to be a growth factor and was named Paramecium growth factor (ParGF). This is the first report of direct proof for the production of a growth factor in an organism other than vertebrates.

Animals↗
PubMed1990

[Recanalization of long segment occlusion of superficial femoral artery by percutaneous transluminal laser angioplasty--report of a case].

Percutaneous Transluminal Laser Angioplasty (PTLA) for 46 cm complete occlusion of right superficial femoral and popliteal artery was successfully carried out. Intravenous digital subtraction angiography five months after the procedure showed almost complete recanalization of the arteries, and good flow of the contrast medium through the femoral and popliteal artery. Only Percutaneous Transluminal Angioplasty (PTA) was previously done for the stenosis of right popliteal artery, but restenosis of the artery took place. On this occasion PTLA was carried out to treat stenosis of the popliteal artery as well as the femoral artery lesions. It is speculated that one of the major causes of reocclusion of the femoral and popliteal artery is due to recurrence of a few portions of severe stenosis of superficial femoral and popliteal arteries. This case will illustrate the long term effect of PTLA, because stenotic segments treated only with balloon dilatation recurred, but those stenoses treated with laser did not recur.

Angioplasty, Balloon↗
PubMed1990

Inhibition of actomyosin subfragment 1 ATPase activity by analog peptides of the actin-binding site around the Cys(SH1) of myosin heavy chain.

The synthetic heptapeptide, Ile-Arg-Ile-Cys-Arg-Lsy-Gly-ethoxy, an analog of one of the actin binding sites on myosin head (S-site) (Suzuki, R., Nishi, N., Tokura, S., and Morita, F. (1987) J. Biol. Chem. 262, 11410-11412) was found to completely inhibit the acto-S-1 (myosin subfragment 1) ATPase activity. The effect of the heptapeptide on the binding ability of S-1 for F-actin was determined by an ultracentrifugal separation. Results indicated that the heptapeptide scarcely dissociated the acto-S-1 complex during the ATPase reaction. Consistent results were obtained from the acto-S-1 ATPase activities determined as a function of S-1 concentrations in the absence or presence of the heptapeptide at a fixed F-actin concentration. The heptapeptide reduced the maximum acto-S-1 ATPase activity without affecting the apparent dissociation constant of the acto-S-1 complex. The heptapeptide bound by a site on actin complementary to the S-site probably inhibits the activation of S-1 ATPase by F-actin. These results suggest that S-1 ATPase is necessary to rebind transiently with F-actin at the S-site in order to be activated by F-actin. This is consistent with the activation mechanism proposed assuming the two actin-binding sites on S-1 ATPase (Katoh, T., and Morita F. (1984) J. Biochem. (Tokyo) 96, 1223-1230).

Actins↗
PubMed1990

Production and significance of TGF-beta in AT-3 metastatic cell line established from the Dunning rat prostatic adenocarcinoma.

A colony formation assay using NRK-49F cells revealed that a metastatic cell line, AT-3, established from the Dunning prostatic carcinoma could produce TGF-beta in a latent form. TGF-beta at a concentration as low as 0.05 ng/ml either stimulated the attachment or detachment of AT-3 cells depending on the kind of culture media. Acid extracts from conditioned medium (5 micrograms/ml) showed the activity comparable to that of TGF-beta (5 ng/ml). The detached cells were able to grow in suspension. TGF-beta (0.1 ng/ml) could also stimulate the growth of MC3T3-El osteoblasts established from mouse calvaria. These results suggest that TGF-beta is a key growth factor for osteoblastic bony metastasis of prostate cancer.

Adenocarcinoma↗
PubMed1990

Differences in growth requirements between epithelial and stromal cells derived from rat ventral prostate in serum-free primary culture.

Different procedures of enzymatic digestion of rat prostatic tissue and unique sets of mitogenic factors made it possible to culture practically pure populations of epithelial and stromal cells without previous separation of the two types of cells. Keratin-positive epithelial cells dissociated by trypsin and collagenase from adult rat ventral prostate proliferated in medium WAJC 404 supplemented with epidermal growth factor, insulin, cholera toxin, and bovine pituitary extract. Proliferation of epithelial cells was completely inhibited by dexamethasone as low as 30 nM. On the other hand, fibroblast-like stromal cells released by trypsin digestion required a plastic substratum coated with calf serum or fibronectin, and proliferated in Eagle's minimum essential medium supplemented with cholera toxin, bovine pituitary extract, dexamethasone, and bovine serum albumin. Epidermal growth factor and insulin had negligible effect on proliferation of stromal cells. Physiological concentrations of dihydrotestosterone and estradiol showed no effect on proliferation of both types of cells.

Animals↗
PubMed1990

Roles of the amino acid side chains in the actin-binding S-site of myosin heavy chain.

The heptapeptide Ile-Arg-Ile-Cys-Arg-Lys-Gly-OEt is the analog of the S-site, one of the actin-binding sites in myosin [Suzuki et al. (1987) J. Biol. Chem. 262, 11410-11412]. Various substituted heptapeptides were synthesized, and the dissociation constants of each acto-heptapeptide complex was measured. Comparison of the dissociation constants indicated that the hydrophobic side chain of Ile-1 was critical for the binding with F-actin, but not that of Ile-3. The positive charge and the side chain length of Arg-2 were also important. The presence of a sulfur atom in the Cys-4 was also necessary. The affinity of the N-terminal Ile-Arg-Ile part for F-actin was influenced by the kind of residues in the C-terminal tetrapeptide part. Based on these results, the side chains of Ile(702), Arg(703), and Cys(SH1)(705) in myosin subfragment-1 heavy chain were assigned to be critical for the binding with F-actin. The amino acid sequence of S-1 heavy chain containing these critical residues for the S-site from residue number 700 to 717 can be predicted as an analogue of the segment B of the ATP-binding site [Walker et al. (1982) EMBO J. 1, 945-951]. The actin-binding S-site possibly shares a part of the ATP-binding site in myosin. We discuss the possibility that the S-site is an inhibitory site of myosin ATPase and the so-called actin-activation of myosin ATPase is a deinhibition induced by transient binding of F-actin to the S-site.

Actins↗
PubMed1990

[Comparison of factors related to hospitalization versus home care of elderly].

This study was done to identify factors affecting present hospitalization versus home care in 4,578 elderly subjects representing 87.1% of the elderly population living in S. city near Osaka. Subjects or their families were asked by interviews regarding the age of the subjects, the kind of persons living together in the family unit, the kind of housing, the number of rooms in the family dwelling, and health conditions. Subjects were also asked whether he or she could walk unassisted and whether home care would be preferred in case of an illness. Among the 153 hospitalized subjects, ability to walk, age, and the number of rooms were all significant factors, in decreasing order. Among the 1,193 persons who preferred home care in case of an illness, the number of rooms, age, ability to walk, and the size of the family unit were all significant factors, in decreasing order. Among subjects who could not walk unassisted, the number of rooms was the main factor determining their admission and not preferring home care if their condition worsened. Thus, although the ability to walk is the major factor among the factors we investigated, housing conditions are also important if home care is to be possible.

Aged↗