Optics: measuring and testing – Blood analysis
Patent
1989-12-18
1991-12-10
McGraw, Vincent P.
Optics: measuring and testing
Blood analysis
356 40, 356427, 250214L, G01N 3348, G01N 2190, H01J 4014
Patent
active
050712470
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to medical instrumentation and, in particular, to methods for the analysis of aggregations of thrombocytes also known as blood platelets and devices utilizing this method.
2. Description of the Related Art
Blood cells are known to form aggregates in response to some physiological agents, referred to as aggregation inducers hereinbelow, such as: ADP, platelet activating factor, thrombin, collagen, thromboxane A.sub.2, and others. The ability to form aggregates makes platelets the leading factor in triggering the hemostasis mechanisms. Any disruption in the functional activity of blood platelets lead to pathological changes. Analysis of spontaneous or induced aggregation of blood platelets in response to the inducer action makes it possible to diagnose various pathological conditions associated with disruptions of the cell link of hemostasis. It is important that spontaneous aggregation of thrombocytes or large-size aggregations caused by standard action of an aggregation inducer creates the tendency for thromboses, while a decrease in or the absence of a response to such action creates a tendency to bleeding. Concentration of blood cells, particularly platelets, is also an indication of the physiological condition. Thus, a decrease in concentration of circulating platelets may occur during severe toxicosses, disseminated intravascular coagulation of blood, serious and vast injuries, irregular thrombocytopoiesis, and some other deseases. A change in the concentration of platelets during their in vivo aggregation is a diagnostic indication of the condition of the hemostasis system of a body.
Known in the art are several methods for the analysis of thrombocyte aggregation such as optical microscopy, electronic microscopy and conductometric platelet count. These methods are based on direct counting of the number of thrombocytes and determination of distribution of aggregates in accordance with size in appropriately prepared blood samples. However, methods of preparation of blood samples cause substantial errors in the results because of the action of substances, and in particular fixatives, dyes and the like upon blood cells. In addition, these methods are very labour-consuming and unsuitable for such a rapidly occurring process as aggregation of thrombocytes.
The most similar to the method according to the invention is a photometric method for the analysis of thrombocyte aggregation, comprising measuring intensity of light flux passed through a thrombocyte suspension sample. A standard platelet rich plasma is turbid because of the presence of thrombocytes in the suspension. The value of intensity of light passed through the sample is used for determining concentration of thrombocytes. When aggregates are formed, turbidity decreases, and this is used for recording aggregation. For carrying out the method, a blood sample is illuminated with a light beam, and intensity of light flux passed through the sample is recorded. A change in the light flux passed through the sample during aggregation of thrombocytes gives a typical "picture" of aggregation, and the kinetics and degree of aggregation of thrombocytes are evaluated by maximum increase in light transmission (Journal of Physiology, vol. 162, 1962, London, Born B.V.R. Quantitative Investigation into the Aggregation of Blood Platelets, p. 67).
Known in the art are apparatuses used for carrying out the above described method. They comprise a light flux source, a means for holding a blood sample and for stirring it, and a photosensitive member converting light flux passed through the blood sample into an electric signal.
Thus known in the art is an apparatus for the investigation into aggregation with an automatic ranging of an output signal in which a reference signal is in the form of an electric signal corresponding to a light transmission of an autologous sample of platelet poor plasma. The apparatus has two cell compartments, a sample of platelet rich plasma being placed in one comp
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The Heathway Machinery Co. Ltd.-Aggregation of Blood Platelets by Adenosine.
Diphosphate and Its Reversal-vol. 194, No. 4832-Jun. 9, 1962.
Gabbasov Zufar A.
Gavrilov Ilya J.
Markosian Ruben A
Popov Evgeny G.
Pozin Evgeny Y.
Keesce LaCharles
McGraw Vincent P.
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