MXPA99006285A - A centrifuge apparatus with temperature control means - Google Patents

Abstract

An apparatus is adapted to centrifuge and furthermore automatically handle a container (10) for separating a component, such as fibrin monomer, from plasma. The container (10) comprises a cylindrical member (11) and a piston (25) displaceable therein and comprising a tubular piston rod (12), which extends through the top wall. The piston (25) divides the cylindrical member (11) into a first chamber positioned above said piston (25) between said piston and said top wall and a second chamber positioned below said piston (25). The apparatus comprises a supporting turntable (1) with means for releasably retaining the cylindrical member (11), said supporting turntable being connected to a first activating means (5) for rotating the supporting turntable (1) with the container (10) about the central axis thereof. The apparatus comprises furthermore a rotatably journalled piston activating mechanism (13, 15, 16) adapted to activate the piston by means of a second activating means (21). A heat-emitting device (26, 27) is provided opposite the position of the cylindrical member (11) in the apparatus.

Description

A CENTRIFUGE APPARATUS WITH TEMPERATURE CONTROL MEANS FIELD OF THE INVENTION The present invention relates to methods and apparatuses for centrifuging and monitoring / controlling the temperature of a liquid, for example, blood, inside a centrifugal rotating container.

BACKGROUND OF THE INVENTION The U.S. 5,603,845, WO 96/16713, WO 96/16714 and WO 96/16715 describe a method and a container for the separation of a component, such as fibrin monomer, from the blood or plasma by centrifugation, by means of which the blood is fed to a first annular chamber in a device, wherein the annular chamber is defined by an external cylindrical wall and an internal cylindrical wall, both walls coaxially extending around a common axis, as well as by an upper wall and a lower wall. The upper wall is formed by a displaceable piston body inside Ref .: 30671 the first chamber. This method involves a centrifugation of the device around said common axis to substantially separate the blood in a cell fraction and a fraction of the plasma followed by the fraction of the resulting plasma being transferred while being influenced by the piston body to a second chamber defined by a external cylindrical wall. The outer cylindrical wall extends coaxially with said common axis, thereby a fraction with a fibrin monomer is caused to separate in the second chamber while a suitable enzyme is added. The separation of the fibrin monomer from the plasma fraction in the second chamber is carried out during continuous centrifugation, whereby a polymerized fibrin is deposited in the external cylindrical wall of said second chamber, where later, the fraction of the fluid collected in the bottom of the second chamber is transferred while being influenced by the piston body to the first chamber. The fraction with polymerized fibrin deposited on the cylindrical wall in the second chamber is caused to be dissolved by the addition of a solvent and by centrifugation, where it is later transferred to a receiver container placed inside the piston rod by passing after the capture and filtration of the enzyme, thereby providing a solution containing fibrin monomer.

The U.S. 5,603,845 describes an apparatus for initiating such centrifugation. This apparatus comprises a housing which is basically divided into three components, an upper compartment, a central compartment and a lower compartment. The container with the fluid to be separated is placed in the central compartment. It is placed on a rotating rotary support which is rotatably articulated on a hinge axis, said axis constitutes an output shaft of a motor which is housed in the lower compartment. Accordingly, this motor constitutes a means to general the high rotational speed at which the container is rotated about its central axis to a number of process steps. The last stage of the procedure corresponds to the separation process in which the fluid is subjected to be separated into the components of the desired fluid. The container is retained on the rotating support by means of fastening means which engage the openings formed along the lower flange of the container. An engine is arranged in the upper compartment. Said motor cooperates with a fastening means which is rotatably articulated and adapted to be vertically displaced as well as to engage and cooperate with the piston rod of the container. The centrifugal device corresponds to the apparatus described in the introduction in the specification.

EP 592242 discloses a new fibrin sealant method which prepares and uses the fibrin monomer which is understood to refer to fibrin I, fibrin II or fibrin BB. The monomer can be prepared using apparatus and methods as described in the aforementioned U.S. patents. 5, 603,845, WO 96/16713, WO 96/16714 and WO 96/16715. Essentially, the plasma fibrinogen is subjected to an enzyme, which catalyzes the unfolding of fibrinopeptide A and / or B of fibrinogen, that is, the thrombin or thrombin-like enzyme which converts fibrinogen to fibrin. The non-dynamic fibrin monomer compositions can later be obtained for example, by the solubility of the resulting non-crosslinked fibrin polymer at a low pH, ie, of about pH-4 buffer where the fibrin monomer is hindered from polymerization until the pH rises.

BRIEF DESCRIPTION OF THE INVENTION It has now been found that the process for producing and using the fibrin monomer is increased when the blood or plasma is heated to about 37 ° C during the processing cycle. Accordingly, the present invention involves methods of preparing fibrin monomer solutions and compositions from blood or plasma wherein the blood or plasma is heated to about 37 ° C before and during processing with the enzyme thrombin or thrombin-like enzyme. . In preferred embodiments, the blood is preheated at low rotational speeds, for example, 500-2000 RPM, with a heat source which radiates energy in the visible light range and the temperature of the blood is directly perceived using the formula.

T blood = AT air + BT surface where T blood = the temperature of the blood T air = the temperature of the circulating air T surface = the temperature of the surface of the blood container A = a coefficient of air B = a coefficient for the surface of the container. Using this formula and measuring T air and T surface, the temperature of the blood can be determined. In addition, it can be fed into a control unit which controls the heat source.

BRIEF DESCRIPTION OF THE DIBUKOS The invention will be explained in great detail below with reference to the accompanying drawings, in which Figure 1 is a diagrammatic front view of parts of the apparatus according to the invention and with a container arranged there for the separation of the components of a liquid.

DETAILED DESCRIPTION OF THE PREFERRED MODALITIES In accordance with the present invention, an increased centrifugation system is provided with capabilities to monitor and control the temperature of a liquid, eg, blood, during centrifugation. It has been found that plasma fibrinogen subjected to an enzyme which catalyzes the cleavage of fibrinopeptides A and / or B of fibrinogen, ie a thrombin or thrombin-like enzyme which convert fibrinogen to fibrin, proceed more efficiently when the blood or plasma are at approximately 37 ° C. The careful control of the temperature is important since the temperatures also low will not provide the increased effect and the temperatures that exceed 40 ° C can damage the component and the cells of the blood.

According to the invention, it is particularly advantageous that the heat-emitting device comprises a first heating source for emission of visible light substantially directed towards the blood-containing portion, or the first chamber of the centrifugal container. Correspondingly, the wall of the centrifugal container is selected to be of a visible light transmitting material so that the heat is effectively transferred to the blood with minimal absorption of excess heat by the container itself. Preferred are medical grade plastics such as polycarbonates. The utilization resulting from the release of energy from the device that emits heat through the wall to the blood is thus optimal.

In addition, the heat emitting device can, in accordance with the invention, optionally comprise a second heat source for the emission of infrared radiation is substantially directed towards a second chamber in the container in which, a fraction of the blood will subsequently be transferred by additional processing at the desired temperature. In this way, it is possible to maintain the wall of the container by absorbing the infrared radiation at a desired temperature.

According to the invention, it is particularly preferred that the heat-emitting device is associated with a first temperature sensor for detecting the temperature of the air in the area around or around the container to be handled, as well as with a second temperature sensor for detecting the temperature of the surface of the container, and, further, that a control unit is provided to control the heat emitting device in response to the detected temperatures. Thus, it is ensured in a particularly simple manner that the desired temperatures are maintained.

In addition, the control unit may, in accordance with the invention, be adapted to successively activate the first and second heat sources in response to the part of the container running the separation process. In this way, the desired temperatures are ensured in the most advantageous manner.

According to the invention, the first heat source can be particularly advantageous, a halogen source, and the second heat source a heat metal plate.

The apparatus shown in FIGURE 1 comprises a rotating support 1 which is rotatably articulated in a housing not shown in great detail, by means of a ball bearing 2, compare FIGURE 2. The rotating support is formed integral with an axis or vertical drive shaft 3. The drive shaft or shaft is connected through a coupling 4 to a motor 5 causing the rotary support to follow a rotary motion about a vertical axis of rotation. An activation bar 6 is rotatably articulated coaxially with the axis of internal rotation of the shaft or drive shaft 3 of the rotary support 1, said activation bar 6 is connected through a coupling 7 with a motor mandrel 8 with a mandrel 9. in a manner that when the mandrel of the motor 8 is activated, the activation bar 6 can be displaced vertically upwards or downwards for a releasable retention of a container 10 in the rotary support 1.

The container 10 is placed in the upper part of the rotary support, said container is of the type described in U.S. Pat. 5,603,845 or WO 96/16713, comprises a cylindrical member 11 and a piston 25 shown by dotted lines. The piston 25 is driven by means of a rod of the tubular piston 12 projecting upwards from the upper end of the container 19. The rod of the piston 12 is activated by means of fastening means 13, which in turn, are activated by means of a motor mandrel 15 through a mandrel 16 and an activation bar connected thereto. The fastening means 13 are, moreover, rotatably articulated in a housing 18 through a ball bearing 19. The housing 18 and the mandrel of the motor 15 are secured to a common carrier indicated by dotted lines to the reference numeral 19. This carrier 19 is displaceably mounted on a rail or track 20 and caused to be moved vertically therein by means of a motor 21. The motor 21 co-operates through a ball mandrel with a ball nut 23 stationary secured in the apparatus such that a rotation of the ball mandrel 22 by means of the motor 21 causes a movement of the carrier 19 and consequently of the fastening means 13 along the slide 20.

The apparatus of FIGURE 1 is used in such a way that the container with its contents is subjected to a heat source by centrifugation, which is preferably described here as a halogen bulb 26, is disposed substantially opposite to the area above the piston 26, check the diagrammatic view of FIGURE 1, said halogen focus is adapted to subject this portion of the container 10 to a visible light. In a similar manner, a heat plate 27 is disposed substantially opposite to the area below the piston 25, use the diagrammatic view of FIGURE 1, likewise, said heat plate 27 subjects this portion of the container 10 to infrared radiation. The heat plate 27 can optionally be curved in such a way that substantially a mating curvature occurs at the outer periphery of the container. Both, the halogen focus 26 and the heat plate 27 are connected to a control unit 28 through respective conduits 29 and 39, respectively. The control unit 28 is also connected to the temperature sensor 31 and optionally to the sensor 32 respectively, through conduits 33 and 34 respectively. The temperature sensor 31 is adapted to measure the temperature on the surface of the container portion 10 above the piston 25 while the temperature sensor 32 is adapted to measure the temperature on the surface of the container portion 19 below the piston 25 and these sensors 31, 32 can be, for example, infrared sensors. In addition, a sensor 35 for measuring the temperature of the air around the container 19 is provided. The last temperature sensor 35 is connected to the control unit 28 through a conduit 36. Both, the halogen focus 26 and the heat 27 are controlled by means of the control unit 28 in such a manner that as soon as possible, the blood and the components thereof contained in the container 10 are maintained at a temperature of 37 ° C during the stay within the apparatus.

There are several accompanying difficulties to this. First, the heat element, that is, the focus 26, is not in direct contact with the blood to be heated and neither are some of the temperature sensors. Also, the blood is contained within a plastic container in which it can be taken into consideration. Furthermore, in many processes using such apparatuses, the container with the blood is rotated very fast, that is, it is rotated. All these factors need to be considered, since such a rotary container is extremely difficult for contrary tests of temperature directly in the blood.

It has been found that the temperature of the blood can be reached by measuring indirectly, the temperature of the surface of the container and the temperature of the surrounding air, using the formula i blood ~ AT air "*" Bi surface where Tsangre is the temperature of the blood, Tsuperf? c? e is the temperature on the surface of the wall of the container 37, and Taires is the temperature of the surrounding air.

A and B are coefficients which are functions of the heat transfer coefficient of the air to the surface of the container, respectively, and partially depend on the ratio of the rotation of the container 10.

The coefficients A and B can be obtained experimentally with a series of tests run for a given procedure by experimentally measuring the value of Tsangre, Taire and surface. The Tsangre value can be measured experimentally by stopping the procedure and taking direct temperature readings or by using a commercially available "heat pill", that is, a small temperature-sensitive capsule, which can be placed in the blood during heating for remote readings. These coefficients can also be obtained theoretically using known equations by taking into account the next energy of the container to the air, the next energy from the inside of the wall of the container to the external surface of the wall, and the next energy of the liquid (blood) to the wall of the container, assuming a state of permanence where all the energy is transferred through the wall of the container and the air. In theoretical calculations, the air heat transfer coefficient depends on the rotational velocity of the container in a directly proportionate manner.

In practice, the rotational speed increases the coefficients A and B with high rotational speeds. The higher coefficients are created to make the previous formula less sensitive and less current, lower rotational speeds are therefore less current, for example 500-2500 RPM, use has been found for preheated blood (approximately 100-150 ml) in a centrifugal cylinder contained for processing. Preferably, the speed during the initial heating and the stabilization temperature are about 1000 RPM. These speeds are employed in maintaining the values coefficients for A and B lower and providing a homogeneous mixing of the blood and an external air movement for more uniform heating.

As mentioned above, the halogen focus has been selected because it emits an essentially visible light, the energy of which passes substantially freely through the wall of the container 37 and directly into the portion of the blood 38 without fearing undue amounts of energy of heat absorbed by the material of the wall of the container.

An optional heat plate 27 emitting an infrared light has been selected to heat the portion of the container below the piston 25 because the energy of the infrared light is absorbed in the material in the wall "of the container 37. Such selection of light is the most advantageous selection of this portion of the container 10 because nothing but a relatively small amount of liquid is present within the wall of the container 37 in this portion.Therefore, the heat plate 27 is controlled only by one measure of the surface temperature of the container wall in this portion of the container.This temperature is, as mentioned, measured by means of the temperature sensor 32.

When the described apparatus is used, the halogen focus 26 is initially activated, and this activation continues as long as the portion of the blood placed above the piston 25 is subjected to centrifugation, and the separated desired component is transferred from this position to the area below. of the piston 25 by means of a pulse of the piston 25 through the rod of the piston 12. Subsequently, the halogen focus 26 is deflected and thereby urges the heat plate 27 in this manner the heat to the lowermost portion of the container 10 during the continuous step of the separation process.

The invention has been described with reference to a preferred embodiment. Many modifications can be made without thereby deviating from the scope of the invention. It is for example possible to use other heat sources by emitting the desired light beams instead of the previous heat sources, the halogen bulb 26 and the heat plate 27. Only one heat source can, if desired, be used to cover the entire container providing the heat source that emits light beams of both types. The previous constants A and B have been calculated in consideration of the visible light of the halogen bulb that passes more freely through the wall of the container 37, which is the case, when said wall of the container is made of polycarbonate, which It is very frequent. When the container is made of another plastic material, it may be necessary to adjust the coefficients in question in response to that, said coefficients are found by means of practical tests as described herein.

It is noted that, in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the description herein. Having described the invention as above, the content of the following is claimed as property.

Claims (12)

1. An apparatus for centrifugation and, in addition, automatically manipulating a container for separating a component, such as a fibrin monomer from the plasma, wherein the container comprises a cylindrical member and a displaceable piston therein and comprises a tubular piston rod, the which extends through the upper wall, and wherein said piston divides the cylindrical member into a first chamber positioned above the piston, between the piston and the upper wall and a second chamber positioned below the piston, and wherein said apparatus comprises a rotating support with means for releasably retaining the cylindrical member, said rotating support is connected to a first activation member for rotating the rotatable support with the container around the central axis thereof, and wherein said apparatus further comprises a piston activation mechanism rotatably articulated, adapted to activate the piston by means of a second activation means n, characterized in that a heat-emitting device is provided contrary to the position of the cylindrical member in the apparatus.

2. An apparatus as claimed in claim 1, characterized in that the heat emitting device comprises a first heat source for emitting substantially direct visible light towards the position of the first chamber in the container to be handled.

3. An apparatus as claimed in claim 2, characterized in that the heat-emitting device comprises a second source of heat of emission of infrared radiation substantially direct towards the position of the second chamber in the container to be handled.

4. An apparatus as claimed in claims 1, 2 or 3, characterized in that the heat-emitting device is associated with a first temperature sensor for detecting the air temperature in the area around the container to be handled, as well as with a second temperature sensor for detecting the temperature of the surface of the container, and a control unit provided for controlling the heat emitting device in response to the detected temperatures.

5. An apparatus as claimed in claim 4, characterized in that the control unit is adapted to successively activate the first and second heat sources in response to the part of the container running the separation process.

6. An apparatus as claimed in claim 2, characterized in that the first heat source is a halogen source.

7. An apparatus as claimed in claim 3, characterized in that the second heat source is a metal heat plate.

8. A method for converting fibrinogen to fibrin, characterized in that it comprises a) heating a blood or plasma sample at about 37 ° C; and b) subjecting said sample to an enzyme which catalyzes the unfolding of fibrinopeptides A and / or B of fibrinogen in said blood or plasma.

9. The method of claim 8, characterized in that said step (b) of the method is performed under centrifugation.

10. The method of claim 8, characterized in that the blood is separated centrifugally in a blood cell fraction and a plasma fraction before step (b).

11. A method of indirectly determining the temperature of a blood sample in a container, characterized in that it comprises a) measuring the temperature of the external surface of the container; b) measure the temperature of the air surrounding the container; and c) use the formula T blood = l air "*" BT surface wherein A is a heat transfer coefficient for the surrounding air; B is a heat transfer coefficient for the surface of the container; solve for the temperature of the blood.

12. A method of controlling the temperature of blood in a container, characterized in that it comprises using an apparatus comprising a container with blood there, a source of heat and a control unit for said source of heat with a control unit in response to a inherent determination as claimed in claim 11.