초록 ▼

Systems and techniques for forming microcellular polymeric material, via injection molding, blow molding, continuous extrusion, or the like, at very low blowing agent levels, are described. The invention involves, in one aspect, the discovery of a region of very low blowing agent level where, surpri

Systems and techniques for forming microcellular polymeric material, via injection molding, blow molding, continuous extrusion, or the like, at very low blowing agent levels, are described. The invention involves, in one aspect, the discovery of a region of very low blowing agent level where, surprisingly, microcellular material can be formed. Articles with particularly good surface properties are provided.

대표청구항 ▼

Systems and techniques for forming microcellular polymeric material, via injection molding, blow molding, continuous extrusion, or the like, at very low blowing agent levels, are described. The invention involves, in one aspect, the discovery of a region of very low blowing agent level where, surpri

Systems and techniques for forming microcellular polymeric material, via injection molding, blow molding, continuous extrusion, or the like, at very low blowing agent levels, are described. The invention involves, in one aspect, the discovery of a region of very low blowing agent level where, surprisingly, microcellular material can be formed. Articles with particularly good surface properties are provided. he mammal with an enhancer of nitric oxide synthase after transplanting the hematopoietic tissue. 15. A method according to claim 12 further comprising: d) treating the mammal with an inhibitor of nitric oxide synthase after transplanting the hematopoietic tissue. 16. A method of increasing a population of progenitor blood cells which are capable of undergoing normal hematopoiesis, differentiation and maturation, comprising contacting progenitor cells of blood with multiple doses of at least one inhibitor of nitric oxide synthase, thereby increasing the population of progenitor blood cells. 17. The method of claim 16 wherein the inhibitor is contacted with the blood for a period of days selected from the group consisting of: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 and 12 days. 18. A method according to claim 16 wherein the progenitor cells of the blood are obtained from hematopoietic tissue selected from the group consisting of: bone marrow, umbilical cord vein blood, peripheral blood, fetal liver and long term hematopietic cell cultures. 19. A method according to claim 16 wherein the inhibitor of nitric oxide synthased is selected from the group consisting of L-nitroarginine methyl ester, 2-ethyl-2thiopseudourea, aminoguanidine hemisulfate and N-monomethyl-L-arginine. 20. A method of increasing a population of dividing cells in a tissue of a mammal comprising contacting the cells with multiple doses of at least one inhibitor of nitric oxide. 21. A method according to claim 20 wherein the inhibitor is an inhibitor of nitric oxide synthase. 22. A method according to claim 20 which results in an increase in the size of an organ with which the tissue is associated. 23. A method of decreasing a population of cells in S phase in a tissue of a mammal and inducing differentiation of the cells, comprising contacting the tissue with multiple doses of at least one enhancer or nitric oxide. 24. A method according to claim 23 wherein the enhancer is an enhancer of nitric oxide synthase. 25. A method to claim 23 which results in a decrease in the size of an organ with which the tissue is associated. 26. A method of regenerating tissue in an adult mammal comprising contacting a selected tissue with multiple doses of at least one inhibitor of nitric oxide, thereby inhibiting differentiation and inducing proliferation of cells of the tissue, then contacting the selected tissue with a compound which inhibits proliferation and induces differentiation. 27. The method of claim 26 wherein the compound which inhibits proliferation and induces differentiation is selected from the group consisting of: nitric oxide, a growth factor, or a combination of both. 28. The method of claim 26 wherein the inhibitor of nitric oxide is an inhibitor of nitric oxide synthase. 29. The method of claim 26 which results in an increase in the size of an organ with which the tissue is associated. 30. A method according to claim 26, wherein the tissue is selected from the group consisting of blood, skin, bone, digestive epithelium, fat tissue, bone marrow stroma, cartilage and tendon. 31. A method of repopulating an organ or tissue having normally nondividing cells comprising contacting a selected organ or tissue with multiple doses of at least one inhibitor of nitric oxide, thereby inhibiting differentiation and inducing proliferation of cells of the organ or tissue, then contacting the selected organ or tissue with a compound which inhibits proliferation and induces differentiation. 32. The method of claim 31 wherein the compound which inhibits proliferation and induces differentiation is selected from the group consisting of: nitric oxide, a growth factor, or a combination of both. 33. The method of claim 31 wherein the inhibitor of nitric oxide is an inhibitor of nitric oxide synthase. 34. The method of claim 31 which results in an increase in the size of the organ. 35. A method according to claim 31 wherein the organ or tissue is selected from the group consisting of muscle and nerve fibers. 36. A method of producing a subpopulation of hematopoietic cells in hematopoietic tissue comprising the steps of: a) contacting the hematopoietic tissue with multiple doses of at least one inhibitor of nitric oxide synthase, thereby producing hematopoietic tissue having an increased population of hematopoietic stem cells which are capable of undergoing normal hematopoiesis, differentiation and maturation; and b) contacting the hematopoietic tissue with at least one hematopoietic growth factor selected to induce specific differentiation of the hematopoietic stem cell population, thereby producing a subpopulation of hematopoietic tissue. 37. The method of claim 36 wherein the inhibitor is contacted with the bone marrow for a period of days selected for the group consisting of: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 and 12 days. 38. A method according to claim 36 wherein the inhibitor of nitric oxide synthase is selected from the group consisting of L-nitroarginine methyl ester, 2-ethyl-2-thiopseudourea, aminoguanidine hemisulfate and N-monomethyl-L-arginine. 39. A method of increasing a population of cells in S phase in a tissue of a mammal, comprising contacting the tissue with multiple doses of at least one inhibitor of nitric oxide. 40. A method according to claim 39 wherein the cells in S phase can be used in gene therapy.