Abstract:
The machine is configured to perform an automated rapid plasma reagent (RPR) agglutination test or other agglutination test. The machine includes a sample rack with multiple sample locations thereon and a reagent rack for storing of reagent. A shaker assembly supports at least one microtiter plate or other well supporting structure thereon with a plurality of wells in the plate. An automated syringe or other aspirator and dispenser accesses samples and reagent and deposits them within wells of the microtiter plate. The shaker assembly shakes multiple samples within the wells of the microtiter plate according to the RPR or other agglutination test. Finally, a camera photographs the wells of the plate, preferably from above with a light source below and the plate at least partially transparent, to evaluate whether the specimen is reactive or non-reactive. Test results and photographic evidence of the test results are preferably archived within a database.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims benefit under Title 35, United States Code §119(e) of U.S. Provisional Application No. 61/847,469 filed on Jul. 17, 2013. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The following invention relates to machines and automated processes for performing automated agglutination assays, such as those used in a rapid plasma reagin (RPR) test. More particularly, this invention relates to machines and processes for automated conducting of assays such as a BD Macro-Vue RPR test, such as that utilized to detect syphilis. 
       BACKGROUND OF THE INVENTION 
       [0003]    Etiological agents responsible for various infections and other diseases, such as syphilis can be detected in a test referred to as a rapid plasma reagin (RPR) test. One specific such assay is known as a BD Macro-Vue RPR test provided by Becton Dickinson and Company of Franklin Lakes, New Jersey. The RPR test is a non-treponemal flocculation test that is used to detect and quantify reagin, an antibody present in serum or plasma as a screen test for syphilis. The etiological agent responsible for syphilis produces at least two kinds of antibodies in human infections. The treponemal antibodies can be detected by florescent treponemal antibody-absorption (FTA-ABS) test whereas the reagin antibody is detected by the RPR antigen test. In the presence of the reagin antibody and the reactive sample, the RPR antigen preparation will produce flocculation consisting of black clumps against the white background of a test card. By contrast, non-reactive samples will yield an even light gray homogenous suspension. 
         [0004]    The RPR test known in the prior art is performed upon EDTA plasma and unheated or heated serum. The specimen should be free of bacterial contamination and haemolysis. A reagent is also utilized in the test. One such reagent is an RPR carbon antigen formed of 0.003 percent cardiolipin, 0.020-0.022 percent lecithin, 0.09 percent cholesterol, 0.0125 M EDTA, 0.1 MNa 2 HPO 4 , 0.01 MKH 2 PO 4 , 0.1 percent thimerosal, 0.0188 percent charcoal and ten percent choline chloride. 
         [0005]    In performing the test the specimen and the reagent are combined together on a test card, such as by applying a drop of each onto the test card. The sample and antigen reagent are not mixed. Rather, they are put onto an automatic rotator, preferably under a humidity cover, with the rotator rotating the combination of the sample and reagent at 100 rpm for eight minutes. Following rotation, a brief hand rotation and tilting of card (three to four times) should be made to aid in differentiating non-reactive from minimally reactive results. Results are then read by studying the combination of the sample and the reagent. A non-reactive sample will have no clumping of the carbon particles in the reagent or very slight roughness, with a smooth gray overall appearance. If the sample is reactive, presence of large aggregates of carbon particles will be visually detected and usually against a clear background. A reactive specimen is considered to have undergone agglutination. In a more detailed variation of the test for more quantitative results, the sample is diluted two to one, four to one, eight to one, sixteen to one, etc. and the reagent is added and after rotation the sample is read for agglutination. In such a test those specimens which are non-reactive can be distinguished from those which are reactive and also minimally reactive specimens can be identified where there is a presence of small or fine aggregates of carbon particles. 
         [0006]    Such a test involves combining a sample of a prepared blood product with an appropriate reagent that includes carbon (e.g. charcoal) particles therein. The reagent may or may not react with the specimen by undergoing flocculation. If the carbon particles become trapped in the flocculation and appear agglutinated or as black clumps against a light background, the specimen is considered to be reactive with the reagent. If the reagent maintains a uniform light gray color with even particle distribution and no clumping, it is indicative of a non-reactive specimen. 
         [0007]    Known RPR tests, are currently known to be performed manually and to involve a variety of steps where the potential for human error or variation in manual performance of the test can result in less reliable results. Also, the test is significantly time intensive even when properly performed, requiring significant amounts of time expenditure by well trained practitioners. Accordingly, a need exists to automate the RPR test to more rapidly and reliably conduct tests with fewer skilled operator hours being required. Furthermore, it is desirable to have test results archived in a variety of different ways for later analysis and for verification of test results. By automating the RPR test, an opportunity is presented for high quality archiving of large numbers of assays for efficient and reliable management of test results from RPR tests or agglutination assays. 
       SUMMARY OF THE INVENTION 
       [0008]    With this invention a process is provided for automated agglutination assay performance for use in tests such as an RPR test, as well as a robotic analyzer for automating the performance of the processes of this invention. The process generally involves a series of steps which can be performed in sequence by the machine of this invention or a related machine for multiple samples. The sequence for one sample can overlap with the sequence for other samples in the same machine to maximize efficacy. 
         [0009]    In one embodiment the steps are generally defined as loading samples/specimens into a sample rack of a machine, loading reagent into a reagent rack of the machine, loading a microtiter plate (or other structure with one or more wells or other test locations therein) onto a shaker assembly of the machine, using an automated microsyringe (or other aspirator and dispenser) to gather a sample from the sample rack and reagent from the reagent rack and deposit the combined sample and reagent in a well of the microtiter plate, shaking the microtiter plate for a predetermined amount of time, detect agglutination such as by photographing the well of the microtiter plate, reading the photograph for a result (reactive or non-reactive) and archiving the photograph and/or result within a database. 
         [0010]    One machine capable of housing a plurality of samples, the reagent, and also to carry the shaker assembly and a carriage for automated motion of the microsyringe and camera is disclosed herein in a preferred embodiment. The machine has an overall housing with a lower region, a mid-region and an upper region. The lower region includes at least one sample rack with multiple locations therein. Most preferably, this sample rack is a “smart rack” which can carry test tubes or other containers of samples which can themselves have a bar code thereon and a scanner is built into the machine so that the samples are intelligently known by the machine to be positioned wherever they are placed within the rack. The reagent rack is also preferably in this lower region of the enclosure of the machine. 
         [0011]    A midlevel of the machine preferably supports a shaker assembly thereon. This shaker assembly preferably only has half of a depth of the overall enclosure and can move forward and rearward. In this way, all of the sample racks and reagent rack locations can be accessed by moving the shaker assembly out of the way (either forward or backward). The shaker assembly is configured to support at least one microtiter plate thereon with each microtiter plate including a plurality of wells thereon. The shaker assembly is also configured with a shaker motor which can shake the microtiter plates upon the shaker assembly. 
         [0012]    An upper portion of the enclosure has a carriage therein which preferably supports both an automated syringe, such as a microsyringe, and a camera. The carriage is configured to allow the microsyringe and camera to move both laterally and forwardly and rearwardly to access each of the samples of the sample rack, each of the wells of the microtiter plates on the shaker assembly and each of the reagent containers within the reagent rack. Appropriate robotics cooperate with the carriage and the shaker assembly to cause the microsyringe to move where required to gather a sample and reagent, and deposit them on an appropriate one of the wells within one of the microtiter plates. The robotic equipment then causes one or more combined specimen and reagent combinations to be shaken by the shaker assembly for a predetermined amount of time. A camera is then carried by the carriage to appropriate locations for photographing the wells of the microtiter plate. In a preferred embodiment the shaker assembly is configured with a diffuser beneath an at least partially transparent microtiter plate and with at least one LED light source below the diffuser, so that the wells of the microtiter plate are backlit during the photographing process. 
       OBJECTS OF THE INVENTION 
       [0013]    Accordingly, a primary object of the present invention is to provide a process for automating an RPR agglutination test. 
         [0014]    Another object of the present invention is to perform an RPR agglutination test in a reliable fashion. 
         [0015]    Another object of the present invention is to perform an RPR agglutination test with more rapid throughput of multiple samples. 
         [0016]    Another object of the present invention is to provide an RPR agglutination test which records results of the test in a manner allowing review of both test results and underlying photographic data upon which test result conclusions are based. 
         [0017]    Another object of the present invention is to provide a machine which automates an RPR agglutination test. 
         [0018]    Another object of the present invention is to provide a machine which accurately performs multiple RPR agglutination tests on multiple separate samples accurately and efficiently. 
         [0019]    Another object of the present invention is to provide a machine and process for performing an RPR agglutination test which minimizes the potential for human error in performing the test. 
         [0020]    Other further objects of the present invention will become apparent from a careful reading of the included drawing figures, the claims and detailed description of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]      FIG. 1  is a perspective view of a machine according to this invention which can perform an RPR or other agglutination test on multiple samples in an automated fashion. 
           [0022]      FIG. 2  is a perspective view of a shaker assembly within a midlevel of the machine of  FIG. 1  and with a single microtiter plate loaded thereon. 
           [0023]      FIG. 3  is a perspective view of that which is shown in  FIG. 2  but with four microtiter plates located thereon and showing rails upon which the shaker assembly is carried. 
           [0024]      FIG. 4  is a full sectional side elevation view of the shaker assembly of  FIGS. 2 and 3  revealing interior details thereof. 
           [0025]      FIG. 5  is a flow chart depicting the steps in the automated agglutination test of this invention. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0026]    Referring to the drawings, wherein like reference numerals represent like parts throughout the various drawing figures, reference numeral  10  ( FIG. 1 ) is directed to a machine for implementing an automated agglutination test process ( FIG. 5 ) of this invention. The machine  10  can be loaded with samples, such as within the sample rack  12  and has multiple wells  32  upon a microtiter plate  30  where samples can be combined with a reagent and shaken a specified time according to the particular agglutination test protocol, such as for an RPR agglutination test. A camera  40  takes photographs of wells  32  within the microtiter  30  to record results of the test. 
         [0027]    In essence, and with particular reference to  FIG. 1 , basic details of the machine  10  are described. The machine  10  includes an enclosure with an interior generally divided into a lower portion, a mid-portion and an upper portion. The overall enclosure can be similar to that of a robotic analyzer for providing a variety of different assays and other tests in an at least partially automated fashion. A lower portion of the interior of the enclosure has at least one sample rack  12  therein. A reagent rack is also located within this lower portion of the interior of the enclosure. A midlevel of the interior of the enclosure has a shaker assembly supported therein. The shaker assembly supports at least one microtiter plate  30  thereon in a manner which facilitates shaking of the entire microtiter plate. An upper portion of the interior of the enclosure has an upper carriage therein. The upper carriage can move both laterally and forwardly and rearwardly. The upper carriage carries an automated syringe, such as a micro syringe, and a camera so that the microsyringe and the camera can access each of the wells  32  of the microtiter plate  30  and so that the microsyringe  18  can access each of the locations in the sample rack  12  and the reagent rack  14 . 
         [0028]    The machine  10  is programmed to manipulate samples and reagents through the microsyringe and the microtiter plate upon the shaker assembly to perform the agglutination test. The test is then read by the camera  40  and results for each sample, along with pictures taken from the camera can be archived within a database which is correlated with information relating to the sample and other details of the test. 
         [0029]    More specifically, and with reference primarily to  FIG. 1 , the particular details of the automated RPR agglutination test as conducted by the machine  10  are described, according to this preferred embodiment disclosed herein. With adjustment, such as using different reagent and/or different shaking procedures, other agglutination tests can similarly be performed. Initially, samples to be tested are loaded into the sample rack  12  of the machine  10 . This sample rack  12  preferably has multiple locations where test tubes or similar structures containing a sample can be placed. Most preferably, the machine  10  includes a barcode scanner  13  thereon and tubes or other structures containing samples can have a barcode thereon so that when the sample is loaded into the rack  12  of the machine  10 , the space in the rack  12  which has been loaded with the sample has been correlated with data associated with the barcode on the sample container. The user thus does not need to keep track of which space in the rack  12  has been loaded with each sample. One such rack  12  suitable for this invention is described in U.S. Published Patent Application No. 2012/0178170, incorporated herein by reference. 
         [0030]    A reagent rack  14  is also provided into which reagent liquid is placed. Details about one appropriate reagent are described above in the Background. Preferably, this reagent rack  14  also includes a cleaning reservoir containing a cleaning solution for cleaning of the microsyringe or other fluid transfer device in between fluid transfer procedures. 
         [0031]    Because the reagent typically has carbon particles within the liquid reagent which have a tendency to settle and detrimentally affect the quality of the reagent taken up by the microsyringe during operation of the procedure of this invention, the reagent rack  14  preferably includes a stirrer associated therewith to keep the carbon particles in suspension. In one embodiment this stirrer is a magnetic stirrer. Such a stirrer can have an impeller contained within the reagent fluid itself and which is caused to spin and keep the reagent stirred by an adjacent rotating magnetic field such as that provided by an electromagnet beneath the reagent rack  14 . Other forms of stirrers could be utilized including mechanical stirrers or stirrers which repeatedly aspirate and dispense reagent sufficiently rapidly to keep the carbon products within the reagent suspended. 
         [0032]    The microtiter plate  30  (or other well supporting structure) is loaded onto the shaker assembly  20 . The microtiter plate  30  includes a plurality of wells  32  or other spaces (or at least one space in a simplest embodiment) thereon which can receive samples and reagents. The shaker assembly  20  is configured so that it can shake such as by rotating the microtiter plate  30  at 100 RPMs with an amplitude of about five millimeters. Preferably, multiple wells  32  are located on the microtiter plate  30  so that multiple samples and reagents can undergo reactions on the common microtiter plate  30  and be shaken by the common shaker assembly  20 . 
         [0033]    An automated microsyringe  18  or other fluid aspirator and dispenser gathers a sample and reagent and deposits the combined sample and reagent onto a well  32  or space on the microtiter plate  30 . Most preferably, this microsyringe  32  is carried upon an upper carriage  16  which can move over the various different samples on the sample rack  12  and can also move over the reagent rack  14 . The microsyringe  18  will typically first gather a predefined quantity of reagent and then further gather a predefined amount of sample and then carry both the reagent and sample to a well  32  on the microtiter plate  30  for dispensing thereon. The microsyringe  18  or other fluid transfer device could then pass to a cleaning reservoir such as adjacent the reagent rack  14  to undergo a cleaning procedure and then can gather further reagent and sample from another location on the sample rack  12  and deposit them onto another well  32  on the microtiter plate  30  located on the shaker assembly  20 ; and so on essentially ad infinitum. 
         [0034]    The microtiter plate  30  undergoes shaking through action of the shaker assembly  20 . The elapsed time is also tracked for each well  32  that has been loaded with a sample and reagent. After an amount of elapsed time and shaking called for by the testing protocol has been achieved, a camera  40  is aligned with the well  32  of the microtiter plate  30  which has the sample and reagent thereon and a photograph is taken of the well  32 . The shaker assembly  20  preferably includes a light diffuser plate  27  beneath the microtiter plate  30  and the microtiter plate  30  (or other well support structure) is preferably formed of a transparent or translucent material to allow light to travel up through the microtiter plate  30 . 
         [0035]    An LED board  29  with a plurality of light emitting diodes surface mounted on a printed circuit board is preferably contained within the shaker assembly  20  beneath the diffuser  27  and supplied with power so that light from the LED board  29  shines up through the diffuser  27  and up through the microtiter plate  30 . A backlit photograph is thus taken by the camera  40  from above looking down on the well  32  of the microtiter plate  30 . 
         [0036]    The LEDs are selected to minimize heat generation and are well ventilated to keep heat from transferring up to the microtiter plate  30 . A fan can also optionally be provided to keep temperature substantially constant and at a desired temperature. 
         [0037]    The photograph taken by the camera  40  is read to determine whether agglutination has occurred or not, and whether a positive or negative test is to be indicated. In one embodiment the reading of the photograph occurs by a trained professional. In other embodiments software might be employed to evaluate the image taken by the camera  40  with the software program automatically determining whether or not a positive test is indicated. 
         [0038]    The photograph and/or the result of reading the photograph can be archived in a database also containing information such as that associated with the barcode on the sample container, and other information such as the date of the test, lot numbers or the reagent, and any other pertinent information (e.g. temperature at time of test, humidity at time of test, atmospheric pressure at time of test, etc.). 
         [0039]    After all the wells  32  in the microtiter plate  30  have been utilized, the microtiter plate  30  can be disposed of or potentially sanitized for reuse. In addition to the basic procedure identified above, with many RPR tests it is desirable to re-perform the tests multiple times at different reagent and/or sample dilution levels. This series of titers can be selected as desired for the parameters of the RPR tests to be conducted. In one embodiment, dilution of the reagent can occur by including a diluting solution in the reagent rack  14  and having the microsyringe  18  or other automated fluid transport device take up both a predetermined amount of reagent and a predetermined amount of diluting solution, and then gathering a predetermined amount of sample from the sample location on the sample rack before transferring the combined gathered liquids to a well  32  or other location on the microtiter plate  30 . 
         [0040]    With particular reference to  FIGS. 1-4 , further details of the machine  10  for performing the process of this invention are described according to one embodiment of this invention. The machine  10  is generally in the form of an enclosure which includes a lower level, midlevel or upper level. The sample racks  12  preferably reside at the lower level and also a reagent rack  14 . The midlevel of the enclosure is configured with the shaker assembly  20  riding upon rails  22  to allow the shaker assembly  20  to move forward and backward within the enclosure at a midlevel above the sample racks  12  and the reagent rack  14 . An upper level of the enclosure includes the upper carriage  16  which rides on a bar which spans the enclosure laterally and can also be carried forwardly and rearwardly within the enclosure. A cover can isolate the entire enclosure, which pivots on a rear hinge. Such a cover is omitted in  FIG. 1  to most clearly show the interior details of the machine  10 . 
         [0041]    The camera  40  and the automated microsyringe  18  (or other fluid aspirator and dispenser) are carried upon the upper carriage  16  in a manner which allows the camera  40  and automated microsyringe  18  to move laterally upon the upper carriage (along arrow A of  FIG. 1 ). The upper carriage itself can move front to back (along arrow B of  FIG. 1 ). Both the camera  40  and automated microsyringe  18  thus have access to be placed directly over each of the wells  32  within the microtiter plates  30  located upon the shaker assembly  20  and the microsyringe has access to each of the sample containers within the sample rack  12  and each of the reagent containers within the reagent rack  14 . 
         [0042]    The shaker assembly  20  is configured so that it can move front to back (along arrow C of  FIG. 1 ). The automated microsyringe is configured so that it can move up and down (along arrow D) such as to access samples located within the sample rack  12  or to access reagents or diluting agents contained within the reagent rack  14 . 
         [0043]    The enclosure preferably includes the barcode scanner  13  built thereinto so that when the sample rack  12  is configured to hold tubes of samples, a barcode sticker can be placed on an exterior of the tube or other sample holder and the tube can first have its associated barcode scanned by the barcode scanner  13  before the tube is placed into one of the locations within the sample rack  12 . The sample rack  12  is “intelligent” in that it can recognize when a tube has been placed therein. The rack  12  thus associates the recently loaded location in the rack  12  with the most recently scanned barcode so that a user does not need to place the test tube into a particular location, but the system automatically records where the sample test tube has been located within the sample rack  12 . In this manner, an operator can load samples into the sample rack  12  by first passing tubes containing samples past the barcode scanner  13  and then placing them into a vacant location on the sample rack  12 . 
         [0044]    During this procedure, the shaker assembly  20  is typically located at a rear of the enclosure. If a large number of samples are being stored on the sample rack,  12  a rear lower portion of the enclosure can have portions of the sample rack  12  located there and the shaker assembly  20  can move to a forward location so that an operator can access locations within the sample rack  12  rear area. Reagent materials are supplied into appropriate reagent locations on the reagent rack  14  when the shaker assembly  20  is in a forward position (moving forward along arrow C of  FIG. 1 ) so that the reagent rack  14  can be accessed. Software and/or sensors can be employed to prevent collisions, such as between the microsyringe  18  and the shaker assembly  20 . 
         [0045]    At least one microtiter plate  30  is loaded onto the shaker assembly  20 . The shaker assembly  20  is configured so that four “6×8” microtiter plates  30  can be provided thereon which each include forty-eight wells  32 . A magnetic stirrer or other stirrer associated with the reagent rack  14  is activated to keep carbon particles within the reagent in suspension. The machine  10  is now ready to automatically perform the RPR assay test according to particular design protocols for the test to be conducted. 
         [0046]    First, the upper carriage  16  is positioned so that the automated microsyringe  18  can access the reagent container on the reagent rack  14 . Any dilution fluid is also gathered from the reagent rack  14 . Next, the automated microsyringe  18  moves upon the upper carriage  16  and the upper carriage  16  moves itself (along arrows A and B of  FIG. 1 ) to place the automated microsyringe  18  over the appropriate location on the sample rack  12  to gather a portion of one of the samples into the microsyringe  18 . A portion of the sample is then aspirated. The microsyringe  18  is then elevated (along arrow D of  FIG. 1 ) and through a combination of movement of the upper carriage  16  and the shaker assembly  20  (along arrows A, B and C) the automated microsyringe is placed over one of the wells  32  on one of the microtiter plates  30  resting on the shaker assembly  20 . The automated microsyringe  18  then is moved down over the well  32  (along arrow D of  FIG. 1 ) and caused to dispense the sample, reagent and any diluting agent into the well  32 . 
         [0047]    A shaker motor  24  is activated and the shaker assembly  20  is caused to shake the microtiter plate  30 . The shaker motor  24  is preferably coupled to an eccentric  26  weight or weights, or coupled to a belt that is unbalanced or other known shaker elements are utilized to perform the desired shaking. The machine  10  keeps track of the time that the reagent and sample came into contact or were dispensed into the well  32 . Multiple times for multiple wells  32  can be simultaneously tracked. The shaker assembly  20 , and upper carriage  16  and automated microsyringe  18  can repeat the above process to gather further reagent and further sample, typically after a self-cleaning procedure for the microsyringe  18  is conducted. In this way, a second sample and reagent combination can be dispensed onto a second well  32  on the microtiter plate  30 . 
         [0048]    Typically, the shaker motor  24  will stop briefly during this dispensing process and then recommence shaking. Any movement of the shaker assembly  20  front to back (along arrow C of  FIGS. 1 and 3 ) is sufficiently slow that it does not interrupt the shaking procedure for the specimen and reagent. This process can be continued potentially for as many tests as there are samples stored on the sample rack  12  and for the number of wells  32  available on the microtiter plates  30  on the shaker assembly  20 . 
         [0049]    After the predetermined amount of time for the assay has elapsed, the upper carriage  16  is moved appropriately to position the camera  40  over wells  32  for which the time has elapsed. The shaker assembly  20  is typically briefly stopped while a photograph is taken with the camera  40 . Before this photograph is taken, the LED board  29  is energized so that light emitting from the LED board passes through the diffuser  27  and through the transparent or translucent microtiter plate  30  for backlighting of the photograph. The shaker assembly  20  can then recommence the shaking procedure. 
         [0050]    An image file is created by the camera  40  and this image file is archived. The image file can also be transmitted to a display for viewing by a trained operator so that the photograph can be read to determine what the result of the test is. Alternatively, the reading of the test can be automated. Test results can be added to this archive data file. 
         [0051]    When all of the wells  32  on all of the microtiter plates  30  have been read the microtiter plates  30  that have been fully utilized can be removed from the shaker assembly  20  and disposed of or washed and sanitized for reuse. New (or cleaned) microtiter plates  30  can be loaded onto the shaker assembly  20 . Sample containers can be removed from the sample rack  12  and new samples loaded into the sample rack  12 , and additional reagent can be provided into the reagent rack  14  and the entire testing procedure can continue with a new set of samples. 
         [0052]    While the machine  10  and process are particularly defined herein for RPR tests such as a test for evaluating whether or not agglutination/flocculation has occurred when a sample is brought into contact with a reagent, other similar tests could also be performed utilizing the process and machine  10  of this invention. In particular, any tests which require combination of two or more liquids together, with or without the requirement of shaking and/or elapsed time, and which require a photograph to create an image of the liquids after any reaction has occurred, could be performed utilizing the machine  10  and process of this invention. 
         [0053]    This disclosure is provided to reveal a preferred embodiment of the invention and a best mode for practicing the invention. Having thus described the invention in this way, it should be apparent that various different modifications can be made to the preferred embodiment without departing from the scope and spirit of this invention disclosure. When structures are identified as a means to perform a function, the identification is intended to include all structures which can perform the function specified. When structures of this invention are identified as being coupled together, such language should be interpreted broadly to include the structures being coupled directly together or coupled together through intervening structures. Such coupling could be permanent or temporary and either in a rigid fashion or in a fashion which allows pivoting, sliding or other relative motion while still providing some form of attachment, unless specifically restricted.