Teijin Limited

Michiyuki Tokashiki

Takeo Shima

Kazumi Iwata

Kimihiko Hamamoto

Yataro Ichikawa

Noritsugu Saiki

Takeo Kawamura

Seiichi Yokoyama

Takanori Urasaki

Kenji Ishimaru

Yoshiharu Takazawa

Takami Arai

Yoshitsugu Nakamura

Yoshitugu Nakamura

A method of producing a useful high-molecular-weight substance by culturing animal cells capable of proliferation, which comprises (A) a culturing step of culturing said animal cells in suspension to form a suspension culture mixture containing the animal cells and a useful high-molecular-weight substance produced by the animal cells; (B) a separating step of separating the animal cells from the suspension culture mixture and withdrawing the culture medium; (C) a removing step of removing low-molecular-weight substances inhibiting the growth of the animal cells from the culture medium, said inhibitor substances being the metabolites of the animal cells and different from the useful high-molecular-weight substance; (D) a recycling step of recycling part or the whole of the culture medium left after removal of the growth-inhibiting low-molecular-weight substances to the culturing step (A); and (E) a recovering step of recovering the useful high-molecular-weight substance accumulated in the culture system. A culture system for culturing the animal cells is also described.

Method of producing useful high-molecular-weight substances by culturing

Adherent 293 human kidney cells are continuously cultured in suspension in serum-free medium. Fresh medium is fed into a culture vessel and spent medium is withdrawn from the vessel. The 293 cells are maintained in small aggregates in suspension at a density of at least 3.times.10.sup.6 cells/ml for 30 days. The formation of large cell clumps is prevented by maintaining the concentration of calcium in the serum-free medium at 0.002 mM to 0.3 mM.

Process for continuously culturing adherent animal cells

A method of cultivating animal or plant cells, which consists essentially of contacting a cultivation liquor having animal or plant cells suspended therein with a liquid fluorocarbon having molecular oxygen dissolved therein, characterized in that said cultivation liquor forms a continuous suspension phase which has cell densities of at least 4.times.10.sup.6 cells/ml, that said contact is made by feeding said liquid fluorocarbon into the cultivation liquor from above the cultivation liquor such that 1 ml of liquid fluorocarbon has a surface area of about 6 to about 300 cm.sup.2 whereby the liquid fluorocarbon falls downward through the cultivation liquor by gravity, and that said cultivation liquor has a volume of at least about 10 liters.

Method of cultivating animal or plant cells

An apparatus for cell culture by perfusion comprising a cell culture tank for suspension culture, said cell culture tank having a suspension cell culture zone, a cell settling zone, an opening for discharging a spent culture medium from the settling zone and an opening for supplying a culture medium to the suspension culture zone, the suspension culture zone and the setting zone being separated by a partition therebetween in a manner to communicate with each other in the lower portion of the settling zone, and the settling zone being formed between the side wall of the cell culture tank and the partition. Another type of apparatus for cell culture having a unit in which main culturing and settling are carried out in a cell settling zone, and a multiunit cell culture apparatus having at least two culturing units which are stacked longitudinally are also described. A method for culturing cells by perfusion in the culture apparatus which comprises withdrawing a substantially cell-free culture medium from the settling zone and introducing a fresh culture medium into the suspension culture zone.

Culture apparatus and method

A fire-resistant thermoplastic polyester resin composition having excellent anti-dripping properties which comprises

Fire-resistant thermoplastic polyester resin compositions and process

A fire-retardant thermoplastic polyester resin composition free from 'dripping' comprising

Fire-retardant thermoplastic polyester resin  compositions and method

In the process for preparing alkenylbenzene by the catalytic reaction of alkylbenzenes and 1,3-butadiene in the presence of an alkali metal catalyst, the improvement which comprises effecting the preliminary contact of the freshly fed alkylbenzene with the reaction product of said catalyst reaction and thereafter catalytically reacting said alkylbenzene with said 1,3-butadiene.

Process for preparing alkenylbenzenes

A process for preparing 2,6-dimethylnaphthalene by the selective isomerization of an isomeric mixture of dimethylnaphthalenes(DMN), characterized in that

Process for preparing 2,6-dimethylnaphthalenes

In the method wherein an alkenylation reaction product liquid obtained by the alkenylation reaction of an alkylbenzene and a C.sub.4 - C.sub.5 conjugated diene in the presence of alkali metal catalysts and containing unreacted alkylbenzene, alkali metal catalysts and organo-alkalimetal compounds is conveyed to a distillation zone at which said alkenylation reaction product liquid is separated by distillation to recover an alkenylbenzene-containing fraction and an unreacted alkylbenzene-containing fraction, the improvement which comprises adjusting the total of the concentrations of said alkali metal catalysts and organo-alkalimetal compounds in said alkenylation reaction product liquid introduced to the distillation zone so as to be 0.09 - 15 milligram atoms per kilogram of said product liquid, calculated as alkalimetal atoms, and thereafter conducting the distillation of said product liquid under conditions of non-addition of alcohols.

Method of separating and recovering alkenylbenzenes and unreacted

In the process for preparing monoalkenylbenzenes by reacting an alkylbenzene and a C.sub.4 - C.sub.5 conjugated diene in the presence of an alkali metal catalyst while passing the reactants progressively through a series of successive reaction zones substantially isolated from each other under non-back-flow conditions, the reaction being carried out at this time while feeding said alkylbenzene and alkali metal catalyst to the first reaction zone and the conjugated diene separately to at least two of said zones, and thereafter withdrawing the reaction product from the final reaction zone of said series; the improvement which comprises (1) reacting the reactants including the alkylbenzene, C.sub.4 - C.sub.5 conjugated diene and alkali metal catalyst under boiling conditions in at least one of the reaction zone selected from the second and subsequent reaction zones; and (2) recovering the evaporated product from said reaction zone or zones as a liquid and recycling same to a reaction zone preceding that at which the product was evaporated.

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Hachioji, Japan

Michiyuki Tokashiki