Hirohisa Omura

Antitumor potency of ascorbic, dehydroascorbic or 2,3-diketogulonic acid and their action on deoxyribonucleic acid.

Three nutritively significant enediol compounds mentioned in above title can inhibit sarcoma-180 growth. The inhibition by ascorbic acid is enhanced by cupric ions. These enediols depolymerize DNA, particularly in co-operation with copper. Dehydroascorbic acid is able to break denatured DNA and to bring about single strand scission for native one. A mixture of dehydroascorbate and Cu decomposes apurinic acid and liberates deoxy-cytidylic acid from it. Only the oligo-form pf pyrimidine tetra- and penta-nucleotides is disintegrated by this reagent. The results were briefly discussed in relation to metabolic carcinostasis and to the formulation of Yamafuji effect causing cellular differentiation and anomalization. Die im obigen Titel erwähnten, drei nutritiv bedeutenden Endiol-Verbindungen können Sarkom-180 hemmen. Die hemmende Wirksamkeit von Ascorbinsäure wird durch Cupri-Ionen verstärkt. Diese Endiolen depolymerisieren DNS, besonders unter Mitwirkung von Kupfer. Dehydroascorbinsäure besitzt die Fähigkeit, denaturierte DNS zu brechen und eine einstrangige Spaltung für native Nucleinsäure zu bewirken. Eine Mischung von Dehydroascorbat und Cu zersetzt Apurinsäure und trennt daraus Deoxy-cyctidylsäure. Nur die Oligo-Form von Pyrimidin-Tetra- und Penta-Nucleotiden wird durch dieses Reagens desintegriert. Die Ergebnisse wurden im Zusammenhang mit der metabolischen Carcinostasis und der Formulierung des cellulären, Differenzierung und Anomalisation verursachenden Yamafuji-Effekts kurz diskutiert.

HO-323, a human B-lymphoblastoid cell line useful for making human-human hybridomas.

A 6-thioguanine-resistant human B-lymphoblastoid cell line, HO-323, was isolated for making human-human hybridomas with high efficiency. Fusions with peripheral blood lymphocytes of systemic lupus erythematosus (SLE) patients and lymphocytes isolated from lymph nodes of lung and breast cancer patients yield constantly more than one hybridoma clones per 10(5) HO-323 cells plated. HO323 cells also fused with lymphocytes from normal peripheral blood to give hybridomas in the same efficiency. The HO-323 cells were diploid with 46 chromosomes and non-secretors of immunoglobulins. This parent cells doubled every 15 hr and could proliferate in serum-containing medium, even if they were plated at low cell density of less than 10(3) cells/ml. The cells could grow in serum-free medium as well as in serum-containing medium, and the resultant human-human hybridomas could also grow in the same media.

Egg yolk lipoprotein, a new supplement for the growth of mammalian cells in serum-free medium : Egg yolk lipoprotein for serum-free growth of cells.

Egg yolk lipoprotein promoted growth of a wide variety of mammalian cell lines, including plasma-cytomas and epithelial cell lines, in serum-free medium. The lipoprotein was active for cell growth when used with insulin, transferrin, ethanolamine and selenite. The most active lipoprotein fraction (YLP-pI7.5) was purified to give a single peak by chromatofocusing and gel filtration, and was homogeneous on a 0.35% agarose gel electrophoretogram. The lipoprotein was characterised as a very low density lipoprotein with a protein content of only 1.3%. This lipoprotein had an optimal concentration of 300 μg/ml (4 μg protein/ml). It was easily separable from proteinous molecules secreted into the serum-free medium by the cells, since it floated on the surface of the medium after addition of ammonium sulfate, to precipitate protein, and centrifugation. An associated structure of lipid and protein seemed to be still necessary for the lipoprotein to exhibit a growth promoting activity.

PRODUCTION OF HUMAN-HUMAN HYBRIDOMAS SECRETING MONOCLONAL ANTIBODIES REACTIVE TO BREAST CANCER CELL LINES

SummaryWe produced human-human hybridomas by fusing lymph node lymphocytes of breast cancer patients with a fusion partner, HO-323 cells, in the presence of 50% polyethylene glycol, and screened hybridomas producing monoclonal antibodiy (MoAb) reactive to a breast cancer cell line, MCF-7. Among 11 hybridomas secreting IgM reactive to MCF-7, four hybridomas (H15A3, H15F2, K15B4, and K15C3) produced IgM reacting specifically to breast cancer cell lines (MCF-7 and HBC-5). Among them, H15A3 proliferated in a serum-free (RDF) medium supplemented with insulin, transferrin, ethanolamine, selenium, and endothelial cell growth supplement, as fast as in 10% FCS-RDF medium. According to transfer blotting analysis, the H15F2 MoAb reacted with a 40 000 dalton antigen in MCF-7 cells.

Formation of mutagens by amino-carbonyl reactions

The formation of mutagens by amino-carbonyl reactions of 20 kinds of amino acid and sugars after heating at 100 degrees C for 10 h was examined by the Ames test. The browned solutions of Gly, Ala, Val, Leu, Ile, Ser, Thr, Gln, Lys X HCl, Arg, Phe, Cys, Met and Pro with Glc caused mutation of Salmonella typhimurium TA100 and/or TA98 with or without S9 mix. The presence of S9 mix increased the mutagenic activity of the browned solutions of Cys and Phe with Glc on TA100 and of those of Gly, Ala, Val, Ile and Cys on TA98, but decreased the activity of other solutions. No revertants of Salmonella were induced by the browned solutions of Trp, Tyr, Asp, Asn, Glu and (Cys)2 with Glc. Among positive browned solutions, Cys, Lys, Arg and Phe had the stronger activity, but their activity was weak compared with that of pyrolysates or chemical mutagens such as Trp-P-1, Trp-P-2 and 4-nitroquinoline-N-oxide. The mutagenic activity of the browned solutions increased with prolongation of heating time and varied with the pH of the reaction mixture. Fru, Gal, Ara, Xyl, Man, Lac and Suc also had the ability to form mutagens in the browning reactions with amino acids.

Immunoglobulin production stimulating and inhibiting factors derived from human lung adenocarcinoma PC-8 cells : Ig production stimulating factor in PC-8 cells.

Addition of a 3 M KCl extract of a human lung adenocarcinoma PC-8 cells to the culture media of lymphocytes, which were isolated from normal donors and from lung or breast cancer patients, elevated immunoglobulin (Ig) production by 3–5 times in the presence of pokeweed mitogen. However, addition of higher concentration of the extract inhibited Ig production and proliferation of lymphocytes. The Ig production stimulating factor (IPSF) was separated from the inhibiting factor, using 50% ammonium sulfate precipitation. Upon chromatofocusing, IPSF activity was detected mainly in the pH 4.5 fraction but minor activity was also detected in other pH fractions. IPSF also enhanced Ig production of a B-lymphoblastoid cell line transformed by Epstein-Barr virus and a human-human hybridoma, by more than 2-fold. This suggests that IPSF interacts with B-lymphocytes directly to enhance their Ig production. IPSF activity was also detected diversely in human lung squamous carcinoma QG56, human B-lymphoblastoid HO-323, and a T cell line CEM.

Human hybrid immunoglobulin M containing immunoglobulin A

SummarySome hybridoma clones made by fusion of a human lymphoblastoid cell line, HO323 with human B lymphocytes, secreted not only IgA but also IgM-like immunoglobulin molecules. The IgM-like immunoglobulin had a molecular size of 900 K which corresponded to that of IgM. Immunochemical analyses revealed that the IgM-like immunoglobulin contained two monomeric IgA and three monomeric IgM molecules. In the IgA moieties, half of original light chains were replaced withx chains derived from the IgM, and vice versa.

Comparison of Enzymatic Reduction of Diphosphopyridine Nucleotide with Ammonia and Urea

In investigating the properties of the dehydrogenating system from ammonia to nitrate, it has been observed that DPN is reduced with urea also in the presence of an enzyme from fowl liver. The properties of the enzyme are very closely similar to those of ammonium dehydrogenase. However, some fundamental differences have been demonstrated by comparing these two enzymes, especially concerning reduction of TPN, substrate inhibition, formation of some nitrogenous metabolites and reoxidation of DPNH in the reaction mixture. The reaction was postulated to be a dehydrogenation of urea by an enzyme. This activity has also been demonstrated in silkworm and yeast.

Chemical Conversion of Ribonucleoside 5'-S-Methyl Phosphorothiolates into Ribonucleotide Anhydrides Including Adenosine 5'-Triphosphate and Uridine Diphosphate Glucose

Ribonucleotide anhydrides have been prepared from corresponding ribonucleoside 5′-S-methyl phosphorothiolates by demethylthiolation with iodine in dry pyridine at room temperature in the presence of appropriate phosphates such as inorganic orthophosphate, inorganic pyrophosphate or glucose 1-phosphate. Thus synthesis of ribonucleotide anhydrides have been achieved and three ribonucleoside 5′-triphosphates (ATP, CTP and UTP), three ribonucleoside 5′-diphosphates (ADP, CDP and UDP) and a pyrophosphate coenzyme (UDPG) have been synthesized and isolated as lithium salts by charcoal treatment followed by ion exchange chromatography.

Texture Curves and Characteristic Values of Emulsified Product of Sardine with Chicken-egg

凍結イワシフィレーを磨砕し,これに鶏卵,ついで大豆油を加えて乳化処理を行ない,それらの工程におけるテクスチャー曲線を求め,応力が処理工程にともない低下することを認めた.さらに,硬さ,凝集性,付着性,ガム性,ぜい性度などの特性値を求めた.イワシフィレーのみの磨砕物の値は市販マヨネーズのものよりも高かったが,処理工程にともなって,凝集性にはほとんど変化はなく,その他の特性値はいずれも低下し,最終乳化標品の値はマヨネーズのものよりも低くなった.しかし,その低下度は特性値の種類によりそれぞれ異なった. また乳化物調製における鶏卵および大豆油の混合割合をイワシフィレーに対しそれぞれ0～0.5および0～4の範囲に変えて特性値を求めた.その結果,これらの場合も凝集性以外の値は,特性値に応じて程度は異なるが,それぞれ類似の変動を示した.