Stephen L Ledis

US Patent:

7083936, Aug 1, 2006

Filed:

Aug 1, 2003

Appl. No.:

10/633382

Inventors:

Stephen L. Ledis - Pembroke Pines FL, US
Olavi Siiman - Davie FL, US
Cynthia G. Healy - Miami FL, US

Assignee:

Beckman Coulter, Inc. - Fullerton CA

International Classification:

G01N 33/567

US Classification:

435 721, 436518, 436524, 436525, 427 211, 427 213, 427 214, 427127, 427128, 427129, 427 713, 435 5, 435 792, 435177, 435178, 435180, 530812, 530813, 530815, 530816

Abstract:

A composition containing polydisperse aminodextran polymer molecules is soluble in an aqueous solution at a concentration of 10 mg/ml. The molecules therein have a narrow size distribution characterized by an average molecule mean hydrodynamic diameter of greater than 115 nm, a polydispersity index of between 0. 10 and 0. 47, an average molecular weight (MW) greater than 3 million daltons, and an amine content of greater than 50 amines per molecule. Similar soluble compositions contain the polymer molecules with an average MW of greater than 7 million daltons. These compositions are useful in forming reagents by conjugation with proteins for labeling cells. Methods of making these compositions and reagents from conventional mixtures of aminodextran polymers involve fractionation on column chromatography.

US Patent:

42997267, Nov 10, 1981

Filed:

May 7, 1979

Appl. No.:

6/036794

Inventors:

Harold R. Crews - Miami FL
David L. Chastain - Fort Lauderdale FL
Stephen L. Ledis - Hialeah FL

Assignee:

Coulter Electronics, Inc. - Hialeah FL

International Classification:

G01N 3348
C09K 300

US Classification:

252408

Abstract:

A process for preparing whole blood reference controls having long term stability up to six months for devices using electronic means for whole blood determinations including platelet count and mean cell volume and red blood distribution width. The preconditioning diluent for the red blood cells consists essentially of an aqueous solution of lactose, sodium azide, and a non-ionic surfactant and is pH buffered and osmolality adjusted. The media of the whole blood control includes lactose, fungicides and antibiotics, and supplementary agents including purine nucleosides. It also includes additional components which alter red blood cell membranes including bile salts and cholic acid derivatives, phenothiazine compounds and the salts thereof having antihistamine properties, and 4-aminobenzoic acid ester derivatives and their salts having local anesthetic properties. In the process, the red blood cells are separated from the whole blood and preconditioned by the diluent to attain desired size distribution width and volume. The preconditioned red blood cells then are mixed in the media in suitable number for yielding the desired cell count for the whole blood reference control.

US Patent:

56165013, Apr 1, 1997

Filed:

Nov 17, 1995

Appl. No.:

8/560423

Inventors:

Carlos M. Rodriguez - Miami FL
Stephen L. Ledis - Hialeah FL

Assignee:

Coulter Corporation - Miami FL

International Classification:

G01N 3348

US Classification:

436 63

Abstract:

A reticulocyte analyzing method and apparatus in which a biological sample stream of ghosted red cells is passed into and through a point focused beam of light, such as laser light. A light detector structure is positioned with respect to the axis of the light beam to provide a light output pulse indicative of the passage of each cell. Electrically conductive contacts within the fluid stream can provide additional electrical pulse outputs of each cell. A staining reagent can be utilized with a ghosting reagent to further differentiate the reticulocytes. The light and the light and electronic produced output pulses or signals can be combined to define and quantify reticulocytes as distinct from other known cell types.

US Patent:

45215189, Jun 4, 1985

Filed:

Jul 6, 1982

Appl. No.:

6/395530

Inventors:

James H. Carter - Ft. Lauderdale FL
Stephen L. Ledis - Hialeah FL
Harold R. Crews - Miami FL

Assignee:

Coulter Electronics, Inc. - Hialeah FL

International Classification:

G01N 3348
C09K 300

US Classification:

436 10

Abstract:

An isotonic multipurpose blood diluent, and a method for use of this diluent with a weak lysing reagent system which is especially suitable for routine enumeration of traditional hemogram values, and also the determination of lymphoid-myeloid populations of leukocytes, particularly in automatic particle counting systems. This blood diluent is capable of affording accurate, reproducible test results. It is an osmotically balanced aqueous solution of preselected pH containing Procaine hydrochloride for maintaining erythrocyte morphology during operation, N-(2-acetamido)iminodiacetic acid (ADA) as a blood cell stabilizing agent, and bacteriostatic agents including sodium 1-hydroxypyridine-2-thione, and dimethylolurea which, together with the ADA, allow preferential determination of myeloid-lymphoid leukocytes, and other hematological values. The lysing agent is a mixture of an aqueous solution of at least one quaternary ammonium salt having surface active properties, and an alkali metal cyanide.

US Patent:

47511796, Jun 14, 1988

Filed:

May 31, 1984

Appl. No.:

6/615966

Inventors:

Stephen L. Ledis - Hialeah FL
Harold R. Crews - Pembroke Pines FL
Ted Sena - Miami FL

Assignee:

Coulter Electronics, Inc. - Hialeah FL

International Classification:

C12Q 104
C12Q 106
G01N 100
G01N 3348

US Classification:

435 34

Abstract:

This invention describes a reagent system, including saponin in a lysing reagent and a rapidly active cross-linking agent such as glutaraldehyde as a fixing reagent, which reproducably affects whole blood to cause the red blood cells to stromatolyze and modifies the leukocytes to generate data to define four distinct clusters for detection and classification by flow analysis instrumentation. The clusters represent the four major leukocyte types found in blood: lymphocytes, monocytes, neutrophils and eosinophils, thus providing a method of leukocyte differential analysis. The parameters used for the leukocyte classification include combinations of two or more of DC (Coulter) volume, high frequency (RF) size, opacity (RF size/DC volume), light scatter at various angular ranges, and fluorescence at various wavelengths of illumination.

US Patent:

51550440, Oct 13, 1992

Filed:

Dec 12, 1991

Appl. No.:

7/808041

Inventors:

Stephen L. Ledis - Hialeah FL
Harold R. Crews - Pembroke Pines FL
Timothy J. Fischer - Plantation FL
Ted Sena - Miami FL

Assignee:

Coulter Electronics, Inc. - Hialeah FL

International Classification:

G01N 3100

US Classification:

436 17

Abstract:

A method and reagent system are disclosed for the rapid isolation, identification and/or analysis of leukocytes from a whole blood sample. The method and reagent system of this invention has application to any environment in which the study and/or analysis of the leukocyte fraction of whole blood requires their isolation in their native or near native state. One of the environments in which this invention can be used to advantage is in the performance of white cell differentiation on automated instrumentation designed for that purpose. In one of the preferred embodiments of this invention, the lytic reagent can contain a mixture of both formic and acetic acid, with the formic acid comprising the major component thereof and the acetic acid being present in only minor quantities, (if at all). This reagent system is used to selectively effect stromatolysis of red blood cells and create subtle modifications to the leukocyte population to enable their automated differentiation into five (5) sub-populations. The advantage and uniqueness of this reagent system is the surprising speed at which it is able to effect the foregoing objectives (generally less than 10 seconds at room temperature) and the ability to further differentiate the leukocyte population (notably, the granulocyte population).

US Patent:

44851758, Nov 27, 1984

Filed:

Jan 3, 1983

Appl. No.:

6/454926

Inventors:

Stephen L. Ledis - Hialeah FL
Ted Sena - Miami FL
Harold R. Crews - Pembroke Pines FL
James H. Carter - Ft. Lauderdale FL

Assignee:

Coulter Electronics, Inc. - Hialeah FL

International Classification:

G01N 3348
G01N 3372

US Classification:

436 63

Abstract:

A method and reagent system is described for differential determination of three-populations of leukocytes (lymphocyte, monocyte and granulocyte), using an automatic counting system. The reagent system includes a blood diluent and lysing reagent. The blood diluent is an osmotically balanced aqueous solution of ingredients at a preselected pH for maintaining erythrocyte morphology, blood cell stabilizing, buffering and bacteriostatic action. The lysing reagent is a mixture of an aqueous solution of quaternary ammonium salts, which lysing reagent is added to the diluted blood under more mild conditions of concentration and at a slower rate than is current practice in order to obtain an unexpected volumetric modification of at least one of the three-populations of leukocytes, whereby volumetric differential analysis can be accomplished.

US Patent:

42448379, Jan 13, 1981

Filed:

Dec 3, 1979

Appl. No.:

6/099757

Inventors:

Harold R. Crews - Miami FL
Dave Chastain - Ft. Lauderdale FL
Stephen Ledis - Hialeah FL

Assignee:

Coulter Electronics, Inc. - Hialeah FL

International Classification:

G01N 3316
C09K 300

US Classification:

252408

Abstract:

A multi-purpose blood diluent especially suitable for use in electronic enumeration and sizing of blood cells, determination of hemoglobin concentration and their collective indices and platelet parameters in a single blood sample by means of suitable electronic instrumentation. The diluent is characterized as azide-free and capable of affording accurate, reproducible hematological test results from the said suitable electronic instrumentation. The diluent employs a chelating agent which functions as a bacteriostat and fungistat agent to prevent adverse growth of microorganisms, methohexital sodium barbituate as a compatible stabilizing agent for maintaining desired morphology of red blood cells, and an inorganic metallic sulfate for suppressing turbidity caused by abnormal globulins and/or high leukocyte counts which are encountered in certain blood samples. Because of the capability for use of the diluent in platelet determinations by the instrumentation, the diluent further is free of detergent action which would cause bubbles capable of interfering with the enumeration of platelets by the instrumentation. A modified and adjusted embodiment of the diluent enables its use in veterinary laboratory testing applications.