Abstract:
An apparatus includes a smoke emitting section which emits smoke containing particulate matter, a dilution section for diluting the smoke emitted by the smoke emitting section, a clean air unit which supplies clean air to the dilution section, at least one chamber which incorporates a cell-adhered surface and into which the smoke diluted by the dilution section is introduced, and an exhaust section for exhausting the smoke from the chamber and the dilution section. A smoke flow in the chamber is shut off to make the smoke settle down in the chamber and expose the cell-adhered surface to the smoke.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This is a Continuation Application of U.S. patent application Ser. No. 10/793,774, field Mar. 8, 2004, and PCT Application No. PCT/JP02/03399, filed Apr. 4, 2002, which was not published under PCT Article 21(2) in English. 
         [0002]    This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2001-303668, filed Sep. 28, 2001, the entire contents of which are incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0003]    1. Field of the Invention 
         [0004]    The present invention relates to an apparatus for exposing cells to smoke containing particulate matter. This apparatus is aimed for exposure tests of cells to aerosols such as tobacco smoke. However, the apparatus is not limited to them and may be applied to exposure tests using other samples. 
         [0005]    2. Description of the Related Art 
         [0006]    As apparatuses for exposing cultured cells to samples such as smoke and checking their influences on the cells, a Fraunhofer research institute&#39;s exposure apparatus disclosed in Internal Publication Number WO99/36505 and R. J. Reynolds&#39;s exposure apparatus (Food and Chemical Toxicology 36 (1998) 191-197) are known. 
         [0007]    In the Fraunhofer research institute&#39;s exposure apparatus, clean air is made to always flow into a chamber. The smoke emitted by a smoke emitting section is introduced into the chamber through the flow of clean air only when blown, and is brought into contact with a cell in the chamber, thereby exposing the cell to the smoke. 
         [0008]    In the Reynolds&#39;s exposure apparatus, the sample emitted by a smoke emitting section is temporarily retained in a vessel to set a concentration for the sample. The sample whose concentration has been set is always supplied from this vessel into the chamber. The sample is continuously introduced into and exhausted from the chamber. That is, the sample is brought into contact with a cell surface through a continuous flow into the non-sealed chamber, thereby exposing the cell surface to the sample. 
         [0009]    These apparatuses differ in that cell surfaces are exposed to smoke containing particulate matter continuously or intermittently, but are common in that cell surfaces are exposed to a sample by using an exposure principle of bringing a sample into contact with the cell surfaces through the continuous flow of air. These apparatuses are effective when a sample has a vapor phase. 
         [0010]    According to the exposure principle of bringing the sample into contact with the cell surface through the continuous flow of air in exposing a cell surface to a sample, the cell surface may not be sufficiently exposed to smoke containing a particulate phase. 
         [0011]    According to the exposure principle for a conventional apparatus, cell surfaces can be sufficiently exposed to a sample in a vapor phase, on the basis of the diffusion principle. However, a sample in a particulate phase is exhausted through the flow of air continuously flowing in a non-sealed chamber because of the size of particles. This causes a considerable reduction in exposure efficiency of exposure of cells to a particulate phase portion in the sample. In an exposure test conducted by an exposure apparatus having the above exposure principle, smoke containing a particulate phase varies in the exposure ratios of constituents in smoke as compared with a sample in a vapor phase. The test result may not reflect the true influence on the sample. In an exposure test of smoke containing a particulate phase using an apparatus having the conventional exposure principle, a cell surface is not properly exposed to an aerosol amount with a set concentration. 
         [0012]    It is therefore hoped to develop an exposure apparatus having a principle of reliably exposing a cell to a sample such as smoke containing a particulate phase, e.g., tobacco smoke, in particular. 
       BRIEF SUMMARY OF THE INVENTION 
       [0013]    It is an object of the present invention to provide a whole smoke exposure apparatus which allows cells to be sufficiently and efficiently exposed to smoke even in an exposure test using smoke containing a particulate phase and/or a vapor phase as a sample. 
         [0014]    In order to solve the above problems, according to the present invention, there is provided a whole smoke exposure apparatus comprising a smoke emitting section which emits smoke containing particulate matter, dilution means for diluting the smoke emitted by the smoke emitting section, by adding a gas to the smoke, an air unit which supplies a gas to the dilution means, at least one exposure chamber which incorporates a cell-adhered surface and into which the smoke diluted by the dilution means is introduced, blocking means for blocking a gas flow so as to seal the chamber after the smoke is introduced into the chamber, and exhaust means for exhausting the smoke introduced into the chamber. Preferably, the dilution means includes concentration setting means for arbitrarily setting a concentration for a smoke to be diluted. 
         [0015]    According to this arrangement, since the flow of smoke into the chamber is blocked at the time of exposure, smoke with a set concentration is brought into contact with a cell-adhered surface in a sealed state without changing the set concentration, thereby efficiently exposing the cell-adhered surface to the smoke. In the chamber into which the flow of smoke is blocked, since a particulate phase in the sample settles down in the chamber for a predetermined period of time, a cell can be reliably exposed to even smoke containing a particulate phase as well as a vapor phase. In addition, if the dilution means has a concentration setting means for arbitrarily setting a dilution concentration, a predetermined amount of sample can be introduced into the chamber. 
         [0016]    The whole smoke exposure apparatus further comprises a header which is located between the smoke emitting section and the chamber and in which smoke emitted by the smoke emitting section is temporarily stored before being introduced into the chamber. Preferably, the apparatus includes a three-way connector having one pipe line connected to the header, another pipe line connected to the exhaust means, and still another pipe line open to the atmosphere. 
         [0017]    This arrangement is designed to store the sample emitted by the smoke emitting section in the header so as to dilute the sample instead of making a gas always flow in the chamber. Therefore, the sample is not swept away by the continuous flow of a gas, and hence a loss in the absolute amount of sample can be suppressed when the sample is diluted. This also contributes to a reduction in pressure fluctuations at the time of generation of a sample and stabilization of secondary dilution. Furthermore, when smoke in the header is exhausted, an abrupt pressure fluctuation in the header can be prevented by the three-way connector. The sample emitted by the smoke emitting section may be diluted in both the front and rear portions of the header. 
         [0018]    The whole smoke exposure apparatus may include a manifold which is positioned between the smoke emitting section and a plurality of chambers for exposure, and has a piping structure uniformly branched to allow smoke emitted by the smoke emitting section to be introduced to be supplied to the plurality of chamber for exposure. Alternatively, the apparatus may include a dilution tank which is positioned between the smoke emitting section and the plurality of chambers for exposure to allow smoke diluted by the dilution means to flow into the dilution tank, and has a piping structure uniformly connected to the plurality of chambers for exposure. 
         [0019]    According to this arrangement, samples uniform in concentration and amount can be delivered into a plurality of chambers as compared with a case wherein samples are directly delivered from the dilution means into the respective chambers through glass pipes or the like. In the whole smoke exposure apparatus having a plurality of chambers, a high-precision exposure test can be conducted, and the exposure efficiency improves. 
         [0020]    The combination, number, and layout order of constituent elements of the header, manifold, and dilution tank can be arbitrarily changed between the smoke emitting section and the chamber as long as the smoke can be efficiency introduced into the chamber. As an example of the structure of the whole smoke exposure apparatus having these constituent elements, a structure can be conceived which has the smoke emitting section, header, dilution means, and dilution tank arranged in the order named. Another example can be conceived which has the smoke emitting section, header, manifold, and dilution means arranged in the order named (in this case, no dilution tank is provided). 
         [0021]    The chamber has an inlet for the smoke which is positioned at an upper portion of the chamber, and an outlet for the smoke which is positioned near the cell-adhered surface. 
         [0022]    As a consequence, after settling down/exposure, the sample is efficiently exhausted from near the cell-adhered surface. 
         [0023]    The chamber has a structure which has an inlet and outlet for a culture medium in which the cell-adhered surface is to be immersed, and in which the culture medium inlet and outlet are provided at different positions. 
         [0024]    According to the above arrangement, the chamber has a structure having a culture medium inlet and outlet independently formed. As a consequence, the culture medium in which a soluble component in a sample dissolves owing to exposure is discharged from the outlet, and a new culture medium is supplied from the inlet different from the outlet. This makes it possible to prevent a culture medium containing unnecessary substances from mixing with a fresh culture medium. In the whole smoke exposure apparatus having this arrangement, a new culture medium is always supplied into the chamber every time an exposure test is conducted. Therefore, this apparatus is also suitable for consecutive exposure tests to be conducted while culture media are replaced. If there are a plurality of chambers identical to the above chamber, each chamber may have a culture medium inlet and outlet. The replacement speed of culture media is preferably set to a predetermined speed enough to prevent any adverse effect on cells. 
         [0025]    The positions of the culture medium inlet and outlet can be so changed as to improve the culture medium replacement efficiency in accordance with the state in the chamber. For example, one of the inlet and outlet may be position above the other. Preferably, the inlet and outlet have the same arrangement, so that their functions can be interchanged. 
         [0026]    It is preferable that the shape of the chamber be optimally designed to improve the culture medium replacement efficiency. If, for example, the culture medium inlet is positioned above the outlet, the lower portion of the chamber may taper off toward the outlet. According to this shape, since a culture medium automatically gathers at the outlet, the culture medium can be efficiently replaced with a new culture medium. The amount of culture medium required can therefore be reduced. In addition, this can eliminate the fear that soluble components affect a cell. 
         [0027]    Preferably, the cell-adhered surface has at least one hole through which the culture medium passes. 
         [0028]    According to this arrangement, the fluid level of a culture medium can be quickly lowered to a level lower than the cell-adhered surface so as to bring the cell-adhered surface into contact with a sample at the time of exposure, and can be quickly raised to a level higher than the cell-adhered surface so as to protect the cells after exposure. This makes it possible to raise and lower the fluid level of a culture medium in the chamber even during consecutive exposure tests in which a sample is introduced into the chamber, exhausted after exposure, and introduced again into the chamber. The whole smoke exposure apparatus is also suitable for consecutive exposure tests in which the fluid level of a culture medium is raised and lowered. The speed at which the fluid level of a culture medium is raised and lowered is preferably set to a predetermined speed high enough to prevent any adverse effect on cells. 
         [0029]    The whole smoke exposure apparatus may have a means for controlling the fluid level of a culture medium so as to raise and lower it with respect to a cell-adhered surface in the chamber. 
         [0030]    It is preferable that the whole smoke exposure apparatus further comprise warm keeping means for keeping the culture medium and the cell-adhered surface at a constant temperature. 
         [0031]    As this warm keeping means, for example, a circulating device which keeps a constant temperature by circulating an isothermal medium can be used. Preferably, this temperature to be kept is 35° C. to 40° C. 
         [0032]    Preferably, the whole smoke exposure apparatus further comprises means for measuring and controlling a pressure in the chamber. 
         [0033]    According to this arrangement, when a pressure change occurs in each constituent element in operation, the influence of the pressure change on cells can be avoided by controlling the pressure in the chamber. This pressure control can be realized by, for example, opening/closing a valve provided in each pipe line connected to the chamber in accordance with pressure fluctuations. 
         [0034]    More preferably, the whole smoke exposure apparatus further comprises at least one monitor chamber which has a concentration measurement sensor S for measuring a concentration of smoke in the chamber at the time of exposure. 
         [0035]    The preparation of this monitor chamber makes it possible to evaluate the concentration of a sample actually flowing into the chamber in real time. Therefore, more accurate tests can be conducted. 
         [0036]    Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0037]    The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein: 
           [0038]      FIG. 1  is a view showing the first embodiment of a whole smoke exposure apparatus according to the present invention; 
           [0039]      FIG. 2A  is a view showing a main cross-sectional portion of each module; 
           [0040]      FIG. 2B  is a left side view of  FIG. 2A ; 
           [0041]      FIG. 2C  is a right side view of  FIG. 2A ; 
           [0042]      FIG. 2D  is a plan view of  FIG. 2A ; 
           [0043]      FIG. 3  is a plan view of a cell-adhered surface; 
           [0044]      FIG. 4  is a view showing the second embodiment of the whole smoke exposure apparatus according to the present invention; and 
           [0045]      FIG. 5  is a partial perspective view of a manifold according to the second embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0046]    The first embodiment of a whole smoke exposure apparatus according to the present invention will be described in detail below with reference to  FIGS. 1 to 3 . Referring to  FIG. 1 , the whole smoke exposure apparatus denoted by reference numeral  1  has a compressor  2 . The compressor  2  supplies compressed air to a clean air unit  3  connected thereto through a pipe line P 1 . The clean air unit  3  is connected to a clean air supply section  4  and smoke emitting section  5  through a pipe line P 2  branched into two lines. The smoke emitting section  5  is connected to a dilution means  6  through a pipe line P 3 . The dilution means  6  is connected to the clean air supply section  4  through a pipe line P 7 . 
         [0047]    The smoke emitting section  5  has a diluent air section  51 , clean air section  52 , and concentration setting section  53 . The diluent air section  51  having a pair of valves  51 V and clean air section  52  are connected to the two pipe lines branching from the pipe line P 2 . The pipe lines P 2  become a single pipe line P 4  again which is connected to the concentration setting section  53 . The smoke emitting section  5  has a plurality of tobaccos  54  rotatably supported on a revolver type support tool  55 . The tobaccos  54  are connected to the concentration setting section  53  through a cylinder  56  connected to a pipe line P 5  in a T shape. 
         [0048]    The dilution means  6  is connected to five modules  7  through the same number of pipe lines P 6  ( FIG. 1  shows only one of the five modules; an illustration of the four remaining modules is omitted), and is connected to an exhaust means  8  through a pipe line P 8 . The dilution means  6  has a header  61  and concentration setting sections  62  mounted in the respective pipe lines P 6 . Each of the concentration setting sections  62  may have the same function as that of the concentration setting section  53  mounted in the smoke emitting section  5 . 
         [0049]    The exhaust means  8  is connected to a first exhaust tank  81  and a vacuum pump  82  connected thereto through a pipe line P 9 . The first exhaust tank  81  is connected to the header  61  through the pipe line P 8 . The pipe line P 8  is a three-way connector  63  having one line connected to the header  61 , another line connected to the first exhaust tank  81 , and the remaining line open to the atmosphere. 
         [0050]    As described above, the exposure apparatus according to this embodiment is a five-module whole smoke exposure apparatus having five modules. Only one module will be described below. When, however, the apparatus has a plurality of modules as in this embodiment with the five-module structure, all the remaining modules have the same arrangement. 
         [0051]    The module  7  has a dilution tank  71  located at an upper position with respect to chambers  10 . The dilution tank  71  is connected to the header  61  through the pipe line P 6 . The dilution tank  71  is connected to a second exhaust tank  83  through a pipe line P 10 . The second exhaust tank  83  is connected to a second vacuum pump  84  through a pipe line P 11 . 
         [0052]    The whole smoke exposure apparatus  1  according to the first embodiment has the three chambers  10  connected to the dilution tank  71  through pipe lines P 12  for each module. That is, the apparatus has a total of 15 chambers (20 chambers if aerosol monitors (to be described later) are added) and five dilution tanks  71  as a whole. 
         [0053]    The dilution tank  71  is connected to the two pipe lines P 12  having uniform structures. Each of the pipe lines P 12  is equally branched into two lines; a total of four branch lines are connected to the chambers  10 . The three ends of the four branch lines of the pipe lines P 12  are respectively connected to the inlets of the three chambers  10 . The one remaining end is connected to the inlet of an aerosol monitor  11  for monitoring the concentration of smoke in the chamber. 
         [0054]    The aerosol monitor  11  has the same structure as that of the remaining chambers  10  except that a concentration sensor S is mounted in the monitor  11 . The chambers  10 , including the aerosol monitor  11 , have outlets connected to the second exhaust tank  83  through a pipe line P 13 , like the dilution tank  71 . 
         [0055]    The pipe lines P 1  to P 13  respectively have valves each capable of adjusting the flow rate of a sample or clean air flowing in a corresponding of the pipe lines. The types of valves to be used may be selected in accordance with the application purpose of the respective sections. 
         [0056]    The module  7  has a flow path  12  through which isothermal water circulates to keep the temperatures of a culture medium and cell in the chamber  10  constant. The flow path  12  forms a loop running through the module and a first thermostat  13 . 
         [0057]    The module  7  independently has a culture medium supply tank  14 , a tube pump  15  for supplying culture media from the culture medium supply tank  14  to the respective chambers, a culture medium discharge tank  16 , and a tube pump  17  for discharging culture media from the respective chambers into the culture medium discharge tank. That is, each chamber  10  in the module  7  has the above two pipe systems. 
         [0058]    In the first system, the culture medium supply tank  14  is connected to the supply tube pump  15  through a pipe line, and the tube pump  15  is connected to the three chambers  10  through a pipe line P 14  branched into three lines. The culture medium supply tank  14  is housed in a second thermostat  18  to be kept at a constant temperature, preferably about 37° C. 
         [0059]    In the second system, in contrast to the first system, discharge pipe lines P 15  to which the three chambers  10  are connected are merged into one line at a predetermined position and connected to the discharge tube pump  17 . The tube pump  17  is connected to the culture medium discharge tank  16  through a pipe line. 
         [0060]    The tube pumps  15 ,  17  have double-bonded heads. 
         [0061]    The apparatus according to this embodiment is a five-module whole smoke exposure apparatus, in which clean area supply sections, dilution means, vacuum pumps, and first and second thermostats are connected to the respective modules through pipe lines equal in number to the modules. Referring to  FIG. 1 , reference symbols A, B, C, D, E, and F indicate that the four omitted portions have the same structure as that of one portion described in detail. 
         [0062]      FIGS. 2A to 2D  are views showing the details of the main part of the module in the first embodiment shown in  FIG. 1 . As shown in  FIG. 1 , the module  7  has the three chambers  10 . Each of these chambers has an almost cylindrical shape with a lower portion tapering off in a conical shape. These chambers incorporate cell-adhered surfaces  30  to which cells are adhered. Each of the three chambers  10  is comprised of an upper unit  32  and lower unit  33 . A seal member  34  serving as a blocking means for hermetically sealing the lower unit  33  is provided between the upper unit  32  and the lower unit  33 . The seal member  34  is preferably made of a sterilizable material. 
         [0063]    The upper unit  32  has a sample inlet  35  and outlet  36 . The lower unit  33  has a culture medium inlet  37  and outlet  38 . 
         [0064]    The inlet  35  is formed in the peripheral portion of the upper surface of the chamber  10  in the radial direction so as to introduce smoke supplied from the dilution tank. The pipe line P 12  is connected to the inlet  35 . The pipe line P 13  having one end formed into the outlet  36  open to the inside of the chamber extends through almost the center of the upper surface of chamber. That is, the outlet  36  is provided near the cell-adhered surface  30  inside the chamber. 
         [0065]    The cell-adhered surface  30  is a membrane made of polyethylene terephthalate (PET), and has a plurality of holes  31  through which the culture medium supplied into the chamber  10  passes. In this embodiment, as shown in  FIG. 3 , the holes  31  are respectively located at the center of the cell-adhered surface  30  and the upper, lower, left, and right positions surrounding the center. The material for the cell-adhered surface  30 , the number of holes  31 , and the positions of the holes  31  are not limited to those in the above arrangement. 
         [0066]    The inlet  37  for the culture medium supplied from the culture medium supply tank  14  through the pipe line P 14  is formed in the conical inclined surface portion of the lower portion of each chamber  10 . The outlet  38  is formed in a portion corresponding to the vertex of this cone (i.e., near the bottom portion of the chamber  10 ). The pipe line P 15  is connected to the outlet  38 . The inlet  37  located above the outlet  38 . 
         [0067]    The operation of the first embodiment of the whole smoke exposure apparatus  1  having the above embodiment will be described next. Smoke as a sample is sequentially emitted from the tobaccos  54  supported on the revolver type support tool  55  of the smoke emitting section  5 . Smoke can be consecutively emitted by the amount corresponding to the number of tobaccos  54  by sequentially rotating the support tool  55 . The smoke emitted from the tobacco  54  is collected in the cylinder  56  through the pipe line P 5 . The smoke collected in the cylinder  56  is supplied to the concentration setting section  53 , which performs concentration adjustment (primary dilution) using clean air supplied from the diluent air section  51 . The primarily diluted smoke is temporarily stored in the header  61  of the dilution means  6  through the pipe line P 3 . The inside of the above pipe line though which smoke flows is cleaned at predetermined intervals under the control of the clean air section  52 . 
         [0068]    The smoke is temporarily stored in the header  61  and supplied to the concentration setting sections  62  through the pipe lines P 6 . The concentration setting sections  62  are connected to the clean air supply section  4  through the pipe lines P 7  respectively connected to the pipe lines P 6  in a T shape. The concentration of the smoke stored in the header  61  is adjusted (secondary dilution) by using clean air supplied from the clean air supply section  4  to the respective pipe lines P 6 . With this operation, since the smoke is temporarily stored in the header  61  and hardly escapes outside, the absolute amount of smoke suffers a little loss at the time of dilution. 
         [0069]    In addition, the sample in the header  61  is held in the exhaust tank  81  through the pipe line P 8 , and can be exhausted by the vacuum pump  82 , as needed. The pipe line P 8  is the three-way connector  63  having one line open to the atmosphere, and hence prevents the occurrence of a negative pressure between the vacuum pump  82  and the header  61  as the vacuum pump pressure decreases. This makes it possible to reduce pressure fluctuations in each pipe line described above. 
         [0070]    The smoke secondarily diluted by the dilution means can be supplied to the dilution tank  71  placed above each module  7  after being set at a predetermined concentration. When there are a plurality of modules  7 , smoke supplied to the dilution tanks  71  placed above the respective modules  7  may be set at different concentrations. 
         [0071]    The smoke stored in the dilution tank  71  is introduced into the respective chambers  10  from the inlets  35  formed in the upper surfaces of the chambers  10  through the uniformly branched pipe line P 12 . At this time, the diluted smoke is temporarily stored in the dilution tank  71 , and the pipe lines P 12  are uniformly provided for the respective chambers. This structure makes it possible to supply homogeneous smoke into the respective chambers  10 . Therefore, a high-precision exposure test can be conducted. 
         [0072]    When smoke is introduced, the cell-adhered surface  30  has been immersed in the culture medium supplied into each chamber  10  and hence the cell is protected by the culture medium. After smoke is introduced, the fluid level of the culture medium is lowered to a level lower than the cell-adhered surface  30 . When the cell is exposed to the smoke, the entrance/exit of smoke to/from the module  7  is shut off, and the lower unit  33  of the chamber is hermetically sealed by the seal member  34 . By maintaining this state, the smoke settles down in the chamber  10  for a predetermined period of time, and the cell is exposed to the smoke. 
         [0073]    As described above, the cell is protected by the culture medium when a sample is introduced, and hence is free from the influence of the blowing pressure of the sample. In addition, since the module is shut off from the outside at the time of exposure to the smoke, the sample and cells are not influenced by the flow of clean air and the like. That is, in an exposure test by this apparatus, introduction of a sample into the chamber  10  and exposure of a cell to the sample are performed as different steps, and each chamber  10  is shut off from the outside at the time of exposure and functions as a sample reservoir tank. 
         [0074]    In addition, the flow of air in each chamber  10  is blocked by valves  51 V of the diluent air section  51  or a valve in header  61  in at the time of exposure to smoke, and the smoke settles down. For this reason, a cell can be reliably exposed to even smoke containing a particulate phase as well as a vapor phase. For the same reason, the efficiency of exposure of a cell to smoke using this apparatus is very high. 
         [0075]    In addition, the seal member  34  is formed from a sterile member, and hence contamination of the culture medium or cell-adhered surface due to fungi can be prevented. 
         [0076]    Each chamber has a function of measuring and controlling a pressure even at the time of exposure to smoke. This makes it possible to prevent pressure changes occurring in each operation from influencing the cell. 
         [0077]    Isothermal water is supplied from the first thermostat  13  into the module  7  through an inlet  39  and circulates along the flow path  12  for isothermal water in the module  7  to thermally insulate the cell-adhered surface  30  and culture medium. This isothermal water flows out of the module through an outlet  40  and returns to the first thermostat  13 . This isothermal water is preferably set to keep the cell-adhered surface  30  and culture medium at about 37° C. The isothermal water may be another kind of isothermal medium. 
         [0078]    After exposure of the cell to the smoke, the smoke in each chamber is exhausted out of the module through the outlet  36  formed in the center of the upper surface of the chamber and the pipe line P 13 . In this case, as described above, since the outlet  36  is formed near the cell-adhered surface  30 , the exhaust efficiency of the sample after sedimentation/exposure is high. 
         [0079]    Excess part of the sample or clean air in each chamber and the dilution tank  71  is stored in the second exhaust tank  83  through the pipe lines P 10  and P 13 . The stored extra part of the sample or clean air can be exhausted as needed. 
         [0080]    One exposure test is completed through a series of operations from emission of smoke to exhaustion of smoke in the above manner. Such a series of operations can be consecutively performed in accordance with the number of tobaccos  54  held by the revolver type support tool  55  described above. 
         [0081]    Upon completion of one exposure test, the culture medium is replaced with a new, fresh culture medium through the inlet  37  and outlet  38 . As shown in  FIG. 1 , the new culture medium is retained in the culture medium supply tank  14 . The tank  14  is installed in the second thermostat  18 , and the culture medium is preferably held at about 37° C. 
         [0082]    The culture medium is delivered from the culture medium supply tank  14  into the module  7  by the tube pump  15  and supplied into each chamber  10  through the inlet  37  in the module  7 . As described above, at the time of introduction of smoke, a cell is immersed in the culture medium to be protected, and the fluid level of the culture medium is lowered to a level lower than the cell-adhered surface  30  at the time of exposure to the smoke. The raising and lowering of the fluid level of each culture medium can be controlled by a sensor installed for each module  7 . In addition, the fluid level of a culture medium can be quickly raised or lowered by letting the culture medium pass through the holes  31  formed in the cell-adhered surface  30 . The replacement speed of the culture media is set to a predetermined speed high enough to prevent any adverse effect on cells. 
         [0083]    The culture medium in which a soluble component in smoke has dissolved at the time of introduction of the smoke and at the time of exposure to the smoke is discharged from the outlet  38  formed in the lower portion of each chamber  10  by the tube pump  17  and delivered to the culture medium discharge tank  16  through the pipe line P 15 . 
         [0084]    Preferably, since the outlet  38  is formed independently of the culture medium inlet  37 , the culture medium in which a soluble component in a sample has dissolved at the time of exposure can be completely discharged, and a new culture medium can always be supplied. That is, no culture medium containing a soluble component in smoke is mixed with a newly supplied culture medium. In addition, since two pump heads are contact-bonded to the tube pumps  15  and  17 , leakage of a culture medium from piping tubes can be prevented. 
         [0085]    In the first embodiment, the inlet  37  is formed above the outlet  38 , and the lower portion of the chamber  10  tapers off and inclines toward the outlet  38 . This makes it possible to quickly and efficiently replace the culture medium in each chamber  10 . 
         [0086]    As described above, the holes  31  formed in the cell-adhered surface  30  allow the fluid level of a culture medium to be quickly raised and lowered, and the structure of each chamber  10  makes it possible to quickly supply and discharge a culture medium. Replacement of culture media can therefore be done while a sample is blown. Consequently, the chambers  10  of this apparatus allow quick, efficient, consecutive exposure tests. 
         [0087]    Since the module  7  includes at least one aerosol monitor  11  serving as a monitor chamber having a concentration measurement sensor S for measuring the concentration of smoke in each chamber  10  at the time of exposure to the smoke, real-time monitoring in each chamber  10  during exposure to the smoke can be done. This makes it possible to evaluate an actual exposure amount. 
         [0088]    The second embodiment of the whole smoke exposure apparatus according to the present invention will be described in detail below with reference to  FIGS. 4 and 5 . As shown in  FIG. 4 , the basic arrangement and operation of the whole smoke exposure apparatus according to this embodiment are the same as those of the first embodiment. Only the different arrangement from the first embodiment will be described below. 
         [0089]    In the second embodiment, the dilution means  6  includes a header  64  which temporarily stores the smoke emitted by the smoke emitting section  5 , a manifold  65  which is connected to the header  64  through a single pipe line, and a plurality of concentration setting sections  62  which are uniformly connected to the manifold  65 . As shown in  FIG. 5 , the manifold  65  has five pipe lines P 16  which are uniformly branched therefrom. The concentration setting sections  62  are respectively provided for the pipe lines P 16 . The pipe lines P 16  are respectively connected to modules  7 . Each pipe line P 16  is branched into two lines in the module  7 . Each of the two pipe lines is further branched into two pipe lines to form four pipe lines. Three ends of the four branch pipe lines of the pipe line P 16  are respectively connected to the inlets of three chambers  10 . The one remaining end is connected to the inlet of an aerosol monitor  11  for monitoring the concentration of smoke in the chamber. In accordance with this structure, the dilution tank  71  provided in the first embodiment is removed. Referring to  FIG. 4 , reference symbol G indicates that the four omitted portions have the same structure as that of one portion described in detail. 
         [0090]    In the second embodiment, the culture medium supply and discharge directions are opposite to those in the first embodiment. More specifically, the chamber  10  includes a culture medium supply tank  14  connected to an inlet positioned at the bottom portion of the chamber  10 , and a culture medium discharge tank  16  connected to an outlet positioned above the inlet. In correspondence with the arrangement of the chamber  10 , a tank (the culture medium supply tank  14  in the second embodiment) connected to the bottom portion of the chamber  10  is housed in the second thermostat  18  and is preferably held at 37° C. 
         [0091]    The operation of the second embodiment having the above arrangement is basically the same as that of the first embodiment. The smoke emitted by the smoke emitting section  5  is temporarily stored in the header  64  through a pipe line P 3 . The smoke temporarily stored in the header  64  is supplied to the manifold  65  through a pipe line. This smoke can be further supplied to the module  7  after a concentration is set by a plurality of concentration setting sections  63  uniformly connected to the manifold  65 . If there are a plurality of modules, smoke can be supplied to the respective modules  7  after being set at different concentrations. The smoke is delivered to the chambers  10  connected through the four branched pipe lines P 16  in the module  7 . A culture medium is supplied into the chamber  10  through the inlet positioned at the bottom portion of the chamber  10 , and discharged from the outlet located above the inlet. 
         [0092]    In the second embodiment, the smoke emitted by the smoke emitting section  5  can flow into a plurality of chambers  10 , as samples uniform in concentration and amount, from the manifold  65  connected to the header  64  through the concentration setting section  63 . This allows a high-precision exposure test in a whole smoke exposure apparatus  1  having a plurality of chambers  10 , and increases the exposure efficiency. In addition, the installation of the manifold  65  between the header  64  and the concentration setting section  63  makes it possible to stabilize the behavior of diluted smoke and introduce homogenous smoke into the chambers  10 . 
         [0093]    A culture medium is supplied into the chamber  10  through an inlet positioned at the bottom portion of the chamber, and is discharged through an outlet positioned above the inlet. This can prevent the occurrence of air bubbles in a culture medium. 
         [0094]    Other operations and effects in the second embodiment are the same as those in the first embodiment. 
         [0095]    The above modules, chambers, and remaining constituent elements described above are the same in number and shape as those in the first embodiment of the whole smoke exposure apparatus according to the present invention, and are not limited in a narrow sense as well as they fall within the technical idea and the scope of claims of the present invention. 
         [0096]    As described above, in the whole smoke exposure apparatus according to the present invention, since the flow of smoke into the chamber is blocked at the time of exposure, the smoke with a set concentration comes into contact with a cell-adhered surface in a sealed state without changing the set concentration. This allows the cell to be reliably exposed to smoke containing a particulate phase as well as a vapor phase or their mixture. In addition, the cell is free from the influence of the blowing pressure of a sample or the flow of clean air. That is, efficient, high-precision exposure tests can be conducted by the whole smoke exposure apparatus according to the present invention.