US4936998A
Expired / Lapsed
US
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Filter medium for selectively removing leucocytes
Assignee: Asahi Kasei Medical Co Ltd
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Filing: 1987-03-28
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Granted: 1990-06-26
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Expires: 2007-03-28
Abstract
Abstract There is disclosed a filter medium for selectively removing leucocytes, which is composed of fibers, each containing nonionic hydrophilic groups and nitrogen-containing basic functional groups at least in its peripheral surface portion. The present filter medium is useful for efficiently removing leucocytes while holding down the loss of platelets to a minimum and, therefore, the present filter medium can be effectively utilized in platelet transfusions and extracorporeal circulation leucocyte removal therapies and the like.
Inventors
- 👤 Takao Nishimura
- 👤 Yoshiyuki Mizoguchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 06:00
CPC Classifications
B; B01; B01D; B01D39/00; B01D39/14; B01D39/16; B01D39/1607; B01D39/1623; A; A61; A61M; A61M1/00; A61M1/36; A61M1/3679; A61M2202/00; A61M2202/04; A61M2202/0413; A61M2202/0427; A61M2202/0439
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
160 words
A method for selectively removing leukocytes from a suspension containing leucocytes and platelets, comprising: contacting a suspension containing leucocytes and platelets with a filter medium, said filter medium comprising a plurality of fibers, each comprising a body portion and a peripheral surface portion, at least said peripheral surface portion of which comprises a polymer obtained by polymerization of at least one vinyl monomer having a nonionic hydrophilic group with at least one vinyl monomer having a nitrogen-containing basic functional group and has a basic nitrogen atom content of from 0.2 to 4.0% by weight, thereby causing said leucocytes to selectively adhere to said filter medium while allowing the resultant platelet-enriched suspension substantially free of leucocytes to pass through said filter medium, and collecting said platelet-enriched suspension, and wherein said collected platelet-enriched suspension is adapted to be used for platelet transfusion or to be returned to a donor of said suspension containing leucocytes and platelets for performing extracorporeal leucocyte removal therapy.
Claim 2
Independent Claim
160 words
A method for selectively removing leukocytes from a suspension containing leucocytes and platelets, comprising: contacting a suspension containing leucocytes and platelets with a filter medium, said filter medium comprising a plurality of fibers, each comprising a body portion and a peripheral surface portion, at least said peripheral surface portion of which comprises a polymer obtained by polymerization of at least one vinyl monomer having a nonionic hydrophilic group with at least one vinyl monomer having a nitrogen-containing basic functional group and has a basic nitrogen atom content of from 0.2 to 4.0% by weight, thereby causing said leucocytes to selectively adhere to said filter medium while allowing the resultant platelet-enriched suspension substantially free of leucocytes to pass through said filter medium, and collecting said platelet-enriched suspension, and wherein said collected platelet-enriched suspension is adapted to be used for platelet transfusion or to be returned to a donor of said suspension containing leucocytes and platelets for performing extracorporeal leucocyte removal therapy.
Claim 3
Dependent Claim
24 words
The method according to claim 1; wherein the basic nitrogen atom content of said peripheral surface portion is from 0.2 to 1.5% by weight.
Claim 4
Dependent Claim
17 words
The method according to claim 1, wherein the average fiber diameter is from 10 μm or less.
Claim 5
Dependent Claim
20 words
The method according to claim 3, wherein the average fiber diameter is from 0.3 μm to less than 3.0 μm.
Claim 6
Dependent Claim
18 words
The method according to claim 1, wherein said filter medium is in the form of a non-woven fabric.
Claim 7
Dependent Claim
37 words
The method according to claim 1, wherein said peripheral surface portion is formed integrally with or separately from said body portion and said body portion has a chemical composition different from that of said peripheral surface portion.
Claim 8
Dependent Claim
61 words
The method according to claim 6, wherein said peripheral surface portion comprises a polymer containing nonionic hydrophilic groups and nitrogen-containing basic functional groups, and has a basic nitrogen atom content of from 0.2 to 4.0% by weight, said peripheral surface portion being comprised of a coating formed on said body portion having a chemical composition different from that of said polymer.
Claim 9
Dependent Claim
18 words
The method according to claim 6, wherein said peripheral surface portion is formed integrally with said body portion.
Claim 10
Independent Claim
29 words
The method according to any one of claims 1 to 3, wherein the basic nitrogen atom content of said peripheral surface portion is from 0.3 to 1.5% by weight.
Claim 11
Dependent Claim
52 words
The method according to claim 1, wherein said peripheral surface portion is formed integrally with said body portion, and each of said body portion and said peripheral surface portion contains nonionic hydrophilic groups and nitrogen-containing basic functional groups and has a basic nitrogen atom content of from 0.2 to 4.0% by weight.
Claim 12
Dependent Claim
56 words
The method according to claim 1, wherein said nonionic hydrophilic group is a hydroxyl group, an amide group, a polyethylene oxide chain or mixtures thereof, and said nitrogen-containing basic functional group is a primary amino group, a secondary amino group, a tertiary amino group, a quaternary ammonium group, a nitrogen-containing aromatic ring group or mixtures thereof.
Claim 13
Dependent Claim
34 words
The method according to claim 1, wherein said vinyl monomer having a nonionic hydrophilic group is selected from the group consisting of 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate, vinyl alcohol, (meth)acrylamide, N-vinyl pyrrolidone and monomethoxy polyethylene glycol methacrylate.
Claim 14
Dependent Claim
52 words
The method according to claim 1, wherein said vinyl monomer having a nitrogen-containing basic functional group is selected from vinyl compounds of the group consisting of allylamine, (meth)acrylic acid derivatives, styrene derivatives and vinyl derivatives of nitrogen-containing aromatic compounds, and from derivatives obtained by converting said vinyl compounds to quaternary ammonium salts.
Claim 15
Dependent Claim
127 words
A filter medium for selectively removing leucocytes, which comprises a plurality of fibers, each comprising a body portion and a peripheral surface portion, at least said peripheral surface portion of which comprises a polymer obtained by polymerization of at least one vinyl monomer having a nonionic hydrophilic group with at least one vinyl monomer having a nitrogen-containing basic functional group and has a basic nitrogen atom content of from 0.2 to 4.0% by weight, said filter medium being for use in collecting a substantially leucocyte free, platelet-enriched suspension from a suspension containing leucocytes and platelets, said collected platelet-enriched suspension being adapted to be used for platelet transfusion or to be returned to a donor of said suspension containing leucocytes and platelets for performing extracorporeal leucocyte removal therapy.
Claim 16
Dependent Claim
127 words
A filter medium for selectively removing leucocytes, which comprises a plurality of fibers, each comprising a body portion and a peripheral surface portion, at least said peripheral surface portion of which comprises a polymer obtained by polymerization of at least one vinyl monomer having a nonionic hydrophilic group with at least one vinyl monomer having a nitrogen-containing basic functional group and has a basic nitrogen atom content of from 0.2 to 4.0% by weight, said filter medium being for use in collecting a substantially leucocyte free, platelet-enriched suspension from a suspension containing leucocytes and platelets, said collected platelet-enriched suspension being adapted to be used for platelet transfusion or to be returned to a donor of said suspension containing leucocytes and platelets for performing extracorporeal leucocyte removal therapy.
Claim 17
Dependent Claim
19 words
A filter medium according to claim 14, wherein each fiber has a diameter of from 10 μm or less.
Claim 18
Dependent Claim
22 words
The filter medium according to claim 14, wherein each fiber has a diameter of from 0.3 μm to less than 3.0 μm.
Claim 19
Dependent Claim
21 words
The filter medium according to any one of claims 14 to 16, which is in the form of a non-woven fabric.
Claim 20
Dependent Claim
43 words
The filter medium according to any one of claims 14 to 16, wherein said peripheral surface portion is formed integrally with or separately from said body portion and said body portion has a chemical composition different from that of said peripheral surface portion.
Claim 21
Dependent Claim
62 words
The filter medium according to claim 18, wherein said peripheral surface portion comprises a polymer containing nonionic hydrophilic groups and nitrogen-containing basic functional groups, and has a basic nitrogen atom content of from 0.2 to 4.0% by weight, said peripheral surface portion being comprised of a coating formed on said body portion having a chemical composition different from that of said polymer.
Claim 22
Dependent Claim
19 words
The filter medium according to claim 18, wherein said peripheral surface portion is formed integrally with said body portion.
Claim 23
Dependent Claim
40 words
The filter medium according to any one of claims 14 to 16, wherein the basic nitrogen atom content of said peripheral surface portion which contains nonionic hydrophilic groups and nitrogen-containing basic functional groups is from 0.3 to 1.5% by weight.
Claim 24
Dependent Claim
53 words
The filter medium according to claim 14, wherein said peripheral surface portion is formed integrally with said body portion, and each of said body portion and said peripheral surface portion contains nonionic hydrophilic groups and nitrogen-containing basic functional groups and has a basic nitrogen atom content of from 0.2 to 4.0% by weight.
Claim 25
Dependent Claim
57 words
The filter medium according to claim 14, wherein said nonionic hydrophilic group is a hydroxyl group, an amide group, a polyethylene oxide chain or mixtures thereof, and said nitrogen-containing basic functional group is a primary amino group, a secondary amino group, a tertiary amino group, a quaternary ammonium group, a nitrogen-containing aromatic ring group or mixtures thereof.
Claim 26
Dependent Claim
35 words
The filter medium according to claim 14, wherein said vinyl monomer having a nonionic hydrophilic group is selected from the group consisting of 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate, vinyl alcohol, (meth)acrylamide, N-vinyl pyrrolidone and monomethoxy polyethylene glycol methacrylate.
Claim 27
Dependent Claim
53 words
The filter medium according to claim 14, wherein said vinyl monomer having a nitrogen-containing basic functional group is selected from vinyl compounds of the group consisting of allylamine, (meth)acrylic acid derivatives, styrene derivatives and vinyl derivatives of nitrogen-containing aromatic compounds, and from derivatives obtained by converting said vinyl compounds to quaternary ammonium salts.
Claim 28
Dependent Claim
25 words
The filter medium according to claim 14, wherein the basic nitrogen atom content of said peripheral surface portion is from 0.2 to 1.5% by weight.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-06-25 | 1993-12-25 | 1994-06-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-06-25 | 1997-12-25 | 1998-06-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-06-25 | 2001-12-25 | 2002-06-26 | $7700.00 | Window Closed / Lapsed |