Abstract: The present invention presents a novel fluorescent solvatochromic dye that (1) has an ionic terminal that makes it easier to use in a hydrophilic surface or in polar solvents, (2) can be efficiently excited by commonly used Argon lasers (488 nm), (3) shifts the wavelength of emitted light according to the change of polarity, and (4) can effectively stain living tissues such as cells and the like. A pyridinium group was introduced to the electron attracting group of the neutral fluorescent solvatochromic dye (Japanese Patent Application Public Disclosure No. 20008-291210 A) displaying an excellent emission wavelength response and synthesized a fluorescent solvatochromic dye. Then it was found that the fluorescence wavelength of the fluorescent solvatochromic dye changed extensively when the polarity changed on a hydrophilic surface and that the fluorescent solvatochromic dye, when altered to a cationic form, stained cell membranes and could be used to observe the behavior thereof.

Abstract: A culture medium is disclosed for inducing the differentiation of visceral preadipocytes into mature visceral adipocytes; the culture medium contains 0.85 to 100 ng/mL insulin and 50 to 250 ng/mL IGF-1. Also disclosed is a method for using the culture medium to induce the differentiation of visceral preadipocytes into mature visceral adipocytes. Use of the differentiation induction system of the present invention enables a substantial induction of adipocyte differentiation without the addition of synthetic differentiation inducers or high insulin concentrations. The mature adipocytes obtained by the differentiation induction system of the present invention are useful for research into the biochemistry and physiology of adipocytes, for screening drugs effective for the treatment of lifestyle-related diseases such as obesity and type 2 diabetes, and for developing diagnostic reagents.

Abstract: The invention provides a method of inducing differentiation of a visceral preadipocyte and a method of culturing a visceral adipocyte comprising culturing the cell in a medium containing serum free of heparin-adsorbable components. The invention also provides for the removal of heparin-adsorbable components by, for example, applying serum to a heparin affinity column thereby adsorbing the heparin-adsorbable component to heparin. A visceral adipocyte cultured by the method of the present invention is useful in a study of differentiation, growth and metabolism of an adipocyte, elucidation of the mechanism of development and progress of diseases such as diabetes, hyperlipemia, hypertension and arteriosclerosis, and development of a drug for preventing and treating such a disease.

Abstract: An artifical skin comprising an insoluble atelocollagen sheet and an epidermal cell layer cultured only on one surface of the sheet, and a method of producing the same are disclosed, which method includes the steps of: forming an insoluble atelocollagen sheet; inoculating epidermal cells only on one surface of the atelocollagen sheet; and suspending the atelocollagen sheet in a liquid culture medium to culture the epidermal cells, thereby forming an epidermal cell layer.

Abstract: An aqueous atelocollagen solution, which can be injected into living bodies as a medical material, has a pH value in the range from about 6.5 to about 8.0 and an osmolality in the range from about 250 to about 320 mOsm/KgH.sub.2 O, and contains a phosphate buffer solution, or glucose and a phosphate buffer solution, as an agent to adjust pH and osmolality within the ranges specified above. This aqueous atelocollagen solution can be prepared by dissolving atelocollagen in an aqueous acidic solution and adding the above-mentioned pH- and osmolality-adjusting agent to the resulting solution in such an amount as to adjust pH and osmolality of the final solution within the ranges mentioned above.