The present invention relates to a puncture device and an in vivo component measurement system.
In order to measure a specific component such as glucose in a tissue fluid of a subject, for example, U.S. Patent Publication No. 2007/0233011 discloses a fine pore formation device which forms fine pores on a skin of a subject by puncturing the skin with a fine needle chip having many fine needles. According to this fine pore formation device, the glucose of the subject is measured in such a way that, after a puncture action, a tissue fluid is extracted from the subject's skin by contacting an extraction cartridge with a site of the puncture. In such measurement, time for extracting the tissue fluid has been previously set up and the subject has measured the time required for the extraction by using a watch or the like which is prepared separately.
However, there is a possibility that the subject forgets the measurement of the extraction time while conducting the puncture operation and the extraction operation or does not notice that the scheduled extraction has been completed.
The scope of the present invention is defined solely by the appended claims, and is not affected to any degree by the statements within this summary.
In accordance with a first aspect of the present invention, there is provided a puncture device which punctures a skin of a subject for extracting a tissue fluid from a puncture site of the subject, comprising:
a timer;
a notifying section which notifies a user that specific time measured by the timer has passed;
a puncture mechanism which punctures the skin; and
an interlock mechanism which causes the timer to start time measurement in conjunction with a puncture action by the puncture mechanism.
In accordance with a second aspect of the present invention, there is provided an in vivo component measurement system comprising:
a puncture device which punctures a skin of a subject for extracting a tissue fluid from a puncture site of the subject, comprising:
a collection member for accumulating a specific component in the tissue fluid extracted from the puncture site punctured by the puncture device; and
a measurement device for obtaining a value related to a quantity of the specific component accumulated in the collection member.
A puncture device 1 (Refer to
The puncture device 1 forms plural fine extraction pores which do not reach up to vascular plexus in a dermis although they penetrate a stratum corneum of epidermis of the skin and reach the stratum granulosum and the like of the epidermis, and exudates a tissue fluid from the extraction pores. This puncture device 1 comprises a main body 1a having a puncture mechanism for puncturing a subject's skin, and a timer unit 140 having a timer function described below. As shown in
[Configuration of Respective Elements of Main Body]
As shown in
As shown in
The chip accommodation tool insertion member 30 is provided for inserting a chip accommodation tool 120 accommodating the fine needle chip 110 (Refer to
Further, according to the present embodiment, the opening 33a formed on the contact surface 32 is configured so that the chip accommodation tool 120 for removably accommodating the fine needle chip 110 (Refer to
The array chuck 40 which functions as a piston for striking or contacting the fine needle chip 110 to or with the subject's skin is configured so that the array chuck 40 is capable of moving in Y direction along the guide groove 16 of the rear cover 10 and the guide groove 26 of the front cover 20. The fine needle chip 110 (Refer to
Here, according to the present embodiment, in a case where two pieces of engagement sections 44 are not engaged with two pieces of lock sections 62 of a release button 60 described below, the array chuck 40 is so configured that the fine needle chip 110 accommodated in the chip accommodation tool 120 is automatically retained by inserting the chip accommodation tool 120 (Refer to
Further, according to the present embodiment, in a case where two pieces of the engagement sections 44 are not engaged with two pieces of the lock sections 62 of the release button 60 described below, the fine needle chip 110 retained by the array chuck 40 is so configured that the fine needle chip 110 is automatically removed from the chuck section 42 of the array chuck 40 by inserting the chip accommodation tool 120 in the opening 33a of the chip accommodation tool insertion member 30.
Further, according to the present embodiment, the chuck section 42 is integrally formed with other sections (body 41, guide section 43a, 43b, engagement section 44, convex 45, and bush section 46) and all are made of synthetic resin.
The spring stopper 50 is provided for supporting the mainspring 80 which biases the array chuck 40 in a direction of arrow mark Y1. This spring stopper 50, as shown in
The release button 60, as shown in
Further, according to the present embodiment, the ejector 70 has a function of discharging the chip accommodation tool 120 accommodating the fine needle chip 110 through the through-hole 33 (Refer to
The mainspring 80 is provided for biasing the array chuck 40 in a direction of arrow mark Y1. The shaft section 51 of the spring stopper 50 is inserted inside the mainspring 80 as shown in
The spring 90a which is installed in the spring installation section 17 of the rear cover 10 and inserted in the boss section 73a of the contact section 73 of the ejector 70 has a function of biasing the ejector 70, which is pressed up in a direction of arrow mark Y2, in a direction of arrow mark Y1 as shown in
[Timer Unit]
Further, the user operates the decision button 161 and the select/manner button 162 for causing the CPU 351 to adjust time of the timer 141, set extraction time, and select a notifying method through the input-output interface 354. For example, according to the present embodiment, when the decision button 161 is pressed down in a state in which the timer unit 140 is not mounted on the main body 1a, a screen displays time as shown in
When the decision button 161 is pressed down in a state in which the portion displaying “minute” blinks, the screen displays extraction time as shown in
Next, when the array chuck 40 is ejectably loaded as described below, the power supply of the display section 160 is turned on, and the extraction time set up by the user is displayed on the display section 160. Subsequently, when the array chuck 40 is ejected, “remaining time” is displayed on the display section 160 as shown in
The timer unit 140 is provided with the memory 352 which memorizes variety of information related to the subject and measurement. The memory 352 is composed of ROM and RAM. As the variety of information memorized by the memory 352, examples are a name of the subject (patient) and a lot and a type of gel being an extraction medium. The timer unit 140 is provided with the connection terminal 353 for transferring these types of information from the timer unit 140 to the measurement device or PC (personal computer). In a case where the puncture device of the present invention is utilized in a medical institution, the subject carries around the timer unit 140 with a gel reservoir member (collection member) for extraction being applied to the puncture site of the subject. A component subject to be measured in the extracted tissue fluid is measured, after the timer unit 140 and the gel reservoir member in which the tissue fluid is extracted and retained are collected after the specific extraction time has passed. Here, it is possible for a measurer to obtain information about the patient being the subject only by receiving the timer unit 140 and the gel reservoir member for extraction, so that work such as recording the variety of information by the measurer is not required.
Further, when extraction time and measurement date and time are memorized by the memory 352 of the timer unit 140, an individual is not required to record separately, and therefore convenience improves.
Further, it is also possible to cause time when the subject has a meal to be memorized. It is possible to review it when the obtained data are analyzed by recording meal time when puncture is performed and measurement starts after the meal or history of meal time.
Further, it is possible to cause the timer unit 140 to record a past blood glucose level of the subject which is obtained by the self-monitoring of blood glucose (SMBG) and it is possible to consider it together with a result of AUC measurement which is currently obtained. Especially, in the case of the SMBG result which is measured in combination with the AUC measurement, the result is possible to be applied to AUC wave analysis.
It is also possible to display these outputs from the timer unit 140 on the display section 160 together with measurement time and it is possible to output the outputs to PC for data analysis from the connection terminal 353 for PC provided in the timer unit 140.
The timer unit 140 is removably mounted on the main body 1a as shown in
When the timer unit 140 is mounted on the main body 1a, as shown in
Further, a guide groove 146 for guiding a rib (not shown) which is formed in a lower side wall defining the concave 20a is formed in other side surface 143b which faces the one side surface 143a of the casing 143.
In a case where the timer unit 140 having the above-mentioned configuration is mounted on the main body 1a so that the timer unit 140 is positioned inside the concave 20a of the front cover 20, the engagement nail 20d of the engagement piece 20e moves in the guide groove 144 in the one side surface 143a of the casing 143, and the rib formed in the lower side wall moves in the guide groove 146 in the other side surface 143b of the casing 143. Here, the engagement nail 20d of the engagement piece 20e moves in the guide groove 144 in contact with the bottom surface 144a of the guide groove 144, and passes over the convex line 145, and is engaged with an engagement concave 147. Mount of the timer unit 140 on the main body 1a is completed by engagement between the engagement nail 20d and the engagement concave 147, and it prevents the timer unit 140 from being removed from the main body 1a due to contact and the like.
As shown in
Further, an engagement piece 152 which is movable is arranged in the housing configured by the front cover 20 and the rear cover 10. This engagement piece 152 has a second projection 152a and a third projection 152b which projects in a perpendicular direction to a projection direction of the second projection 152a. The engagement piece 152 is biased by a coil spring 153 being a bias means which is arranged in the housing in such a direction that the engagement piece 152 is engaged with the tip end 43d of the guide section 43b. The third projection 152b of the engagement piece 152 projects outward from a slit 154 (Refer to
In a state shown in
On the other hand, when the timer unit 140 is mounted on the main body 1a as described below, it is possible to mount the fine needle chip 110 on the array chuck 40 and push the array chuck 40 into the device since the engagement piece 152 moves in such a direction that the engagement with the tip end 43d of the guide section 43b is released. As shown in
A guide groove 155 being a groove is formed in a position which is on a rear surface or the bottom surface 143c (Refer to
Further, a notch 156 (Refer to
[Lock Mechanism and Turn-on Mechanism]
Next, a lock mechanism which inhibits a puncture action while the timer unit is not mounted and a turn-on mechanism which turns on a power supply of the display section 160 by loading the fine needle chip 110 on the array chuck 40 are explained.
In a state in which the timer unit 140 is not mounted on the main body 1a as shown in
When the timer unit 140 is mounted on the main body 1a, the bottom surface 156a of the notch 156 which is formed in a side wall of the casing of the timer unit 140 contacts with the third projection 152b of the engagement piece 152, and moves the engagement piece 152 in such a direction that the second projection 152a recedes from the tip end 43d against bias force of the coil spring 153. Therefore, since engagement between the tip end 43d of the array chuck 40 and the second projection 152a of the engagement piece 152 is released (lock released), it is possible that the array chuck 40 moves opposite to a puncture direction.
When the fine needle chip 110 is mounted on the array chuck 40 and the array chuck 40 is pushed into the device opposite to a puncture direction after the timer unit 140 is mounted on the main body 1a, the tip end 43d as a press member moves in the guide groove 155 of the casing 143 of the timer unit 140, and the tip end 43d presses the tip end 157a of the switch section 157, and the tip end 43d retreats the tip end 157a from inside of the guide groove 155. According to the present embodiment, the power supply of the display section 160 is turned on by pressure of the switch section 157 by the tip end 43d as a press member, and the extraction time set up by the user is displayed on the display section 160. More particularly, when the CPU 351 recognizes the pressure of the switch section 157 through the input-output interface 354, the CPU 351 can turn on the power supply of the display section 160. Here, the power supply of the display section 160 is turned off after a given time has passed.
Next, when the array chuck 40 is ejected by pressing the button section 64 of the release button 60, engagement between the tip end 43d of the array chuck 40 and the tip end 157a of the switch section 157 is released, and the tip end 157a of the switch section 157 again projects inside the guide groove 155. According to the present embodiment, the CPU 351 recognizes release of pressure of the tip end 157a or a puncture action through the input-output interface 354 and causes the timer 141 to start time measurement.
[Chip Accommodation Kit]
Next, with reference to
The fine needle chip 110 is mounted in the array chuck 40 (Refer to
According to the present embodiment, the chip accommodation tool 120 formed of synthetic resin includes an opening 121 for accommodating the fine needle chip 110 (Refer to
Further, according to the present embodiment, as shown in
The sterilization preservation seal 130 is formed of aluminum film and has a function of inhibiting adhesion of viruses, germs, and the like to the fine needle chip 110 which is sterilized by y-ray irradiation. The sterilization preservation seal 130 is applied so as to cover the opening 121 which accommodates the fine needle chip 110 before use, as shown in
According to the present embodiment, there is provided the array chuck 40 for retaining the fine needle chip 110 by inserting the chip accommodation tool 120 in the opening 33a of the chip accommodation tool insertion member 30, in a case where engagement between the engagement section 44 of the array chuck 40 and the lock section 62 of the release button 60 is released. Therefore, it is possible that the subject causes the chuck section 42 of the array chuck 40 to retain the flange portion 112 of the fine needle chip 110 only by moving the puncture tool 1 in such way that the chip accommodation tool 120 is inserted in the opening 33a of the chip accommodation tool insertion member 30. Here, because the lock section 62 (release button 60) which locks the array chuck 40 by engaging with the engagement section 44 of the array chuck 40 is provided and the array chuck 40 is configured so that it can move in Y direction, it is possible that the fine needle chip 110 is retained in the array chuck 40 and the array chuck 40 is locked by the lock section 62 in a state in which the array chuck 40 is moved in a direction of arrow mark Y1 against a bias force by the mainspring 80. Therefore, the subject can set the puncture device 1 to a lock state in which the array chuck 40 retaining the fine needle chip 110 is biased in a direction toward the subject's skin (direction of arrow mark Y2). Thus, the subject can set to a state in which the puncture device 1 can form the fine pores on the subject's skin only by moving the puncture device 1 without requiring troublesome work. Because, by pressing the button section 64 of the release button 60 from this state, engagement between the engagement section 44 of the array chuck 40 and the lock section 62 is released, the fine needle chip 110 can pass through the opening 33a of the chip accommodation tool insertion member 30 and move toward a direction of arrow mark Y2, and the fine pores can be formed at the puncture site of the subject's skin.
Further, according to the present embodiment, when the chip accommodation tool 120 which is empty and does not accommodate the fine needle chip 110 is inserted in the opening 33a of the chip accommodation tool insertion member 30 in a case where the fine needle chip 110 is retained by the array chuck 40 and the engagement between the engagement section 44 of the array chuck 40 and the lock section 62 is released, it is possible that the subject easily removes the fine needle chip 110 which is already used and retained by the array chuck 40 in a state of engagement release from the lock section 62 only by moving the puncture device 1 so as to insert the chip accommodation tool 120 in the opening 33a of the chip accommodation tool insertion member 30. Therefore, it is possible that the subject safely disposes of the used fine needle chip 110 without touching the used fine needle chip 110.
[Example of AUC Measurement]
The puncture device according to the present invention can be preferably used for measuring blood glucose AUC. Hereinafter, an example of a blood glucose AUC measurement using the puncture device of the present invention is described.
First, before explanation of the example, significance and others of the blood glucose AUC measurement used in the present invention are explained.
[AUC Measurement]
Conventionally, as a method of obtaining a value which reflects a total quantity of component circulating in vivo within a specific period, there has been known a method of measuring an area under the blood concentration time curve (AUC). AUC refers to an area which is enclosed with a horizontal axis (time axis) and a curve (in vivo component blood concentration-time curve) described by a graph representing time lapse of a specific blood concentration of in vivo component. For example, in a case of oral drug administration, it is difficult to directly determine a quantity of the drug taken up in the circulating blood. However, it is possible to predict a total quantity of the drug taken up in the circulating blood by using a value obtained from AUC measurement.
In the AUC measurement, blood is sampled plural times every specific time, a specific component quantity in the blood which is sampled at respective time points is acquired, and a graph which represents time lapse of the blood concentration of the in vivo component (specific blood concentration of in vivo component) is obtained.
Further, the blood glucose AUC is an area (unit: mg·h/dl) which is enclosed with curve described by a graph representing time lapse of a blood glucose level and a horizontal axis. The blood glucose AUC is an index which is used for response evaluation of insulin and oral drugs in diabetes treatment. For example, it is possible to predict a total quantity of the glucose circulating in vivo of a subject after glucose load, by measuring based on the blood glucose AUC a value which reflects a total quantity of the glucose (blood sugar) circulating in the blood within a specific time after the glucose load (after meal).
As significance of such measurement of blood glucose AUC, it is considered that the blood glucose AUC measurement can control influence caused by personally different glucose metabolism. In other word, because there is a personal difference in time for showing reaction in the blood glucose level to the glucose load, it is impossible to recognize whether the blood glucose level is at a rise time or at a peak time, by measuring only the blood glucose level at a certain time after the glucose load. Further, even if the blood glucose level at the peak time can be measured, it is still impossible to recognize how long such high blood glucose state lasts. In this respect, in a case where the blood glucose AUC is measured, since a value which reflects a total quantity of the blood glucose circulating in the blood within specific period can be obtained, the measurement value is not influenced by time until the blood glucose level shows reaction to the glucose load. Further, it is possible to predict how long the high blood glucose state lasts based on the measurement value. Therefore, by measuring the blood glucose AUC, it is possible to obtain a value useful for predicting the glucose tolerance due to the glucose load without influence of personally different glucose metabolism.
In the blood glucose AUC measurement, a blood glucose AUC is ordinarily obtained by sampling blood every specific time (e.g. every 30 minutes), obtaining a blood glucose level of the sampled blood respectively, obtaining a graph representing time lapse of the blood glucose level, and obtaining an area enclosed with a curve described by the graph and a horizontal axis.
However, as described above, the conventional AUC measurement method has problems of plural times of blood samplings required within a specific period, high invasiveness, and a heavy burden on the subject.
Therefore, in PCT/JP2009/63668, the present applicant proposes an in vivo component measurement method capable of obtaining a value which reflects a total quantity of components to be measured which circulates in biological body within a specific period while decreasing a subject's burden. According to this in vivo component measurement method, an extraction medium made of pure water is used for extracting the tissue fluid from biological body and accumulating the tissue fluid.
Meanwhile it is considered that the quantity of thus extracted component to be measured, specifically the glucose extraction quantity changes in response to skin states which differ among the subjects. In this consideration, it is possible to calculate a blood glucose level more accurately by amending the glucose extraction quantity with glucose permeability (P) (indicating easiness for glucose to be extracted). For example, according to the in vivo component measurement method of the above-mentioned PCT/JP2009/63668, skin of the subject is punctured with a fine needle and the tissue fluid is extracted through the skin with a fine pore formed thereon. However, even if skins are punctured with the same fine needles, a quantity of extracted glucose of a subject who has soft and thin stratum corneum is large because the fine pore is easily formed. On the other hand, a quantity of the extracted glucose of a subject who has hard and thick stratum corneum is small because the fine pore is hard to be formed. Therefore, U.S. Patent Publication No. 2007/0232875 proposes that glucose permeability (P) in the extracted site of the subject is predicted and a blood glucose level is calculated with computation formula (BG=J/P where BG represents calculated blood glucose level and J represents extracted glucose quantity).
Prediction principle of the glucose permeability (P) in a measurement method described in Patent Publication No. 2007/0232875 is described below. It is known that electrolyte concentration in the tissue fluid is substantially similar among plural subjects having different blood glucose levels. For this reason, it is possible to predict a degree of tissue fluid permeating the skin (i.e. glucose permeability (P)) by measuring the electrolyte quantity which is included in the tissue fluid extracted through the skin. Therefore, pure water containing no electrolyte is used as an extraction medium holding the extracted tissue fluid, electricity is supplied to the extraction medium with the tissue fluid extracted, and electric conductivity (K) is measured so that the electrolyte quantity included in the extracted tissue fluid can be predicted. In other words, it is possible to predict the glucose permeability (P) from the electric conductivity (K) of the electrolyte of the extraction medium with the tissue fluid extracted.
According to the in vivo component measurement method related to PCT/JP2009/63668 using the glucose permeability prediction method described in U.S. Patent Publication No. 2007/0232875, it is possible to measure (predict) a blood glucose AUC of the subject at certain accuracy without giving burden on the subject. However, based on knowledge that quantity of sodium ion among various species of ions (Na+, K+, Ca2+, Mg2+, etc.) is much more highly correlated with the glucose extraction quantity than that of the other ions, glucose permeability is obtained based on only quantity of sodium ion extracted in the example described below.
As shown in
The display unit 201 has a function of displaying measurement results by the analysis unit 203 and data recorded in the recording unit 202. The recording unit 202 is provided for storing past data. The analysis unit 203 has a function of calculating a glucose concentration and a concentration of electrolyte (sodium ion) based on an output value of the electric circuit 206. The installation unit 205 has a concave shape and is configured so as to install the sensor chip 300 and the collection member 400. The electric circuit 206 includes a glucose concentration measurement circuit 206a and a sodium ion concentration measurement circuit 206b. The glucose concentration measurement circuit 206a includes terminals 206c and 206d which are exposed inside the installation unit 205. The sodium ion concentration measurement circuit 206b includes terminals 206e and 206f which are exposed inside the installation unit 205. The electric circuit 206 includes a switch 206g for switching the glucose concentration measurement circuit 206a and the sodium ion concentration measurement circuit 206b. The user can switch the glucose concentration measurement circuit 206a and the sodium ion concentration measurement circuit 206b by operating the operation button 207 to operate the switch 206g. The operation button 207 is provided for switching the switch 206g and switching display of the display unit 201.
As shown in
As shown in
The support member 402 has a support main body 402a having a concave portion and a flange portion 402b formed in outer periphery of the support main body 402a, and the gel 401 is retained inside the concave portion of the support main body 402a. An adhesive layer 403 is formed on a surface of the flange portion 402b, and a peel-off paper 404 for sealing the gel 401 retained in the concave portion is applied to the adhesive layer 403 in a premeasurement state. During measurement, the gel 401 and the adhesive layer 403 are exposed by removing the peel-off paper 404 from the adhesive layer 403 and the collection member 400 is enabled to be applied and fixed to the subject's skin through the adhesive layer 403 in a state in which the gel 401 contacts to the subject's skin.
First, with reference to
First, a site to be measured of the subject is cleaned (Step S1). Next, tissue-fluid extraction time is set up using the timer unit 140 (at this stage, the timer unit 140 is not mounted on the main body 1a), and time is set up as needed in a case where end time is displayed by the display section 160 of the timer unit 140 (Step S2). Subsequently, the timer unit 140 is mounted on the main body 1a, the array chuck 40 is ejected, and the puncture action is carried out (Step S3). Next, the collection member 400 is fit at measurement site (Step S4), tissue fluid extraction starts and accumulation of glucose and sodium ion in the tissue fluid starts (Step S5). Next, it is judged whether or not end of the extraction time set up in Step S2 is notified by the alarm 142 of the timer unit 140 (Step S6). In a case where it is notified, the collection member 400 is removed and the tissue fluid extraction is finished (Step S7). Next, the collection member 400 already finishing extraction is installed in the installation unit 205 of the measurement device 200, the tissue fluid measurement and the blood glucose AUC analysis are carried out (Step S8), and measurement ends.
Hereinafter, respective processes are explained in detail.
First, the subject cleans skin 600 with alcohol and the like for removing objects (sweat, dust, etc.) to be a disturbing factor for measurement results.
Next, the subject sets up time (extraction time) of the timer unit 140 by operating the decision button 161 and the select/manner button 162. The setup time is set at, for example, “3:00” (3 hours). It may be inputted and set up as 180 minutes. In a case where the display section 160 of the timer unit 140 is caused to display end time, time is set up or confirmed as needed.
Now, with respect to “specific time” in the present invention, time measurement starts with the puncture action and ends with time passage of set time (e.g. 3 hours). On the other hand, “extraction time” is a range from time when the subject applies the collection member 400 as an extraction medium on the skin after puncture to time when the subject who is notified that the set time has passed removes the collection member 400 from the skin 600. Strictly, “extraction time” does not correspond with “specific time”. However, time from puncture action to application of the collection member 400 and time from notification of lapse of set time to removal of the collection member 400 are both as short as about dozen seconds to 30 seconds, and both times offset by each other. In view of these, there is no problem to consider that “specific time” set up in the timer unit 140 substantially corresponds with “extraction time” when the tissue fluid is extracted.
Next, the timer unit 140 is mounted on the main body 1a. This mount releases the lock mechanism as described above and the array chuck 40 can be mounted. Then, the fine needle chip 110 is mounted on the array chuck 40, and the array chuck 40 is pushed in depth direction up to the position that the array chuck 40 can be ejected, so that the power supply of the display section 160 is turned on.
Subsequently, a contact surface 32 of the chip accommodation tool insertion member 30 is applied to the subject's skin which is cleaned, the button section 64 of the release button 60 is pressed, and the array chuck 40 is ejected in a direction of puncture. Subsequently, fine pores 601 are formed on the subject's skin 600 by the fine needle 113a of the fine needle chip 110.
Next, as shown in
Next, as shown in
In a case where concentration of the extracted glucose is measured, the subject switches a switch 206g to the glucose concentration measurement circuit 206a by an operation button 207 and instructs start of measurement. Thus, a constant voltage of specific value is applied to the first circuit through a constant voltage control circuit, and a current value IGlc detected by an ammeter is inputted in an analysis unit 203. Here, the following formula (1) is established between the current value (IGlc) and the glucose concentration (CGlc) of the gel 401.
C
Glc
=A·I
Glc
+B (A and B are constant numbers) (1)
The analysis unit 203 calculates the glucose concentration CGlc from the current value IGlc based on the formula (1).
Further, the analysis unit 203 calculates an extraction glucose quantity (MGlc) using thus obtained glucose concentration CGlc, and extraction solvent quantity or a gel volume V (constant number) based on the following formula (2).
M
Glc
=C
Glc
·V (2)
Further, in a case where an extracted sodium ion concentration is measured, the subject switches a switch 206g to the sodium ion concentration measurement circuit 206b by the operation button 207 and instructs start of measurement. Thus, a voltage value VNa is detected by a voltmeter which is connected in parallel with the second circuit and inputted in the analysis unit 203. Here, the following formula (3) is established between the voltage value VNa and a sodium ion concentration CNa of the gel 401.
C
Na
=C·V
Na
+D (C and D are constant numbers) (3)
The analysis unit 203 calculates the sodium ion concentration CNa from the voltage value VNa based on the formula (3).
Further, the analysis unit 203 calculates an extraction rate JNa of sodium ion at the extraction site from the sodium ion concentration CNa, a volume V of the gel 401, and extraction time t based on the following formula (4).
J
Na
=C
Na
·V·l/t (4)
Then, the analysis unit 203 calculates predicted glucose permeability (PGlc(calc)) indicative of easiness of glucose extraction from thus calculated sodium ion extraction rate JNa based on the following formula (5).
P
Glc(calc)=E·JNa+F (E and F are constant numbers) (5)
The formula (5) is obtained as follows.
The glucose permeability indicative of easiness of glucose extraction is originally given by a ratio (this ratio is tentatively referred to as true glucose permeability P·Glc) of the blood glucose AUC obtained by blood sampling to an extracted glucose quantity. As described below, because the indicates constant correlation with the sodium ion extraction rate JNa, an approximation formula is obtained based on the sodium ion extraction rate JNa and the true glucose permeability P·Glc, and the formula (5) can be obtained.
According to the formula (5), it is possible to obtain the predicted glucose permeability PGlc(calc) indicative of easiness of glucose extraction based on sodium ion extraction rate JNa obtainable without blood sampling.
The analysis unit 203 calculates predicted blood glucose AUC (predicted AUCBG) from the extraction glucose quantity MGlc obtained by the formula (2) and the predicted glucose permeability PGlc(calc) obtained by the formula (5), based on the following formula (6).
predicted AUCBG=MGlc/PGlc(calc) (6)
This predicted blood glucose AUC (predicated AUCBG) is a value having high correlation with the blood sampling glucose AUC which is calculated by plural times of blood sampling. A value of the predicated blood glucose AUC is displayed on the display unit 201 and recorded in the recording unit 202. Thus, the measurement process ends.
According to Example 1, the gel 401 in which the tissue fluid extracted from biological body is accumulated in the installation unit 205 of the measurement device 200 is installed, and the glucose concentration and the sodium ion concentration in the gel 401 are measured. However, an analyte in the gel 401 is collected in the pure water and an analyte concentration in thus collected fluid may be measured.
For example, a gel reservoir 420 (the gel 401 is arranged on one surface of a tape member 421) having the gel 401 which finishes extraction of analyte from the skin is set in a collection cartridge 450 for exclusive use. This collection cartridge 450 is formed of a cartridge main body 451 in a box shape, an inlet 452 of the collection fluid is formed on one of facing wall surfaces of the cartridge main body 451, and an outlet 453 of the collection fluid is formed on the other. The gel reservoir 420 is set in the collection cartridge 450 so that the gel 401 projects into the cartridge main body 451 from an opening 454 formed on one surface of the cartridge main body 451.
Next, as shown in
The state of the cartridge main body 451 filled up with the collection liquid 469 is suspended for a given time, and the analyte in the gel 401 is collected in the collection liquid 469. Subsequently, the valve is opened and the collection liquid 469 is transferred to the measurement unit 463 by driving the pump unit 462, as shown in
In the present embodiment, since the timer unit 140 is removably mounted on the main body 1a, it is possible to separate from the main body 1a the timer unit 140 which is lighter and more compact than the main body 1a and carry it conveniently.
Further, in the present embodiment, there is provided the lock mechanism for inhibiting the puncture action of the puncture mechanism of the main body 1a in a case where the timer unit 140 is removed from the main body 1a. Therefore, it is possible to prevent erroneous operation of starting puncture while forgetting that measurement of extraction time.
Further, in the present embodiment, since the turn-on mechanism is provided for turning on the power supply of the display section 160 by loading the fine needle chip 110 on the array chuck 40 in ejectable condition, there is no need to turn on the power supply of the display section 160 in advance. Therefore, according to the present embodiment, it is possible to save consumption power of the timer unit 140.
Meanwhile the present invention is not limited to the embodiment described before but it is possible to appropriately modify design thereof.
For example, although the timer unit 140 is removable with respect to the main body according to the embodiments described before, the timer unit may be locked on and integrated with the main body. In the embodiment described before, the tip end 157a of the switch section 157 is pressed for turning on the power supply of the display section 160, and the pressure is released by the puncture action and time measurement starts by this release. However, two types of switch sections may be set, in which one of them turns on the power supply of the display section 160 and the other starts time measurement.
Further, although it is described that time is set every 10 minutes in this embodiment, there is no problem for setting every 5 minutes.
Further, in the above-described embodiment, the puncture action is activated by pressure of the button section 64 of the release button 60, and the time measurement by the timer 141 is activated by pressure release of the tip end 157a of the switch section 157 which is caused by the tip end 43d of the array chuck 40. However, the button section 64 may be linked with the tip end 157a of the switch section 157 for starting time measurement by the timer 141, and time measurement by the timer 141 may be activated by the pressure action of the button section 64.
Number | Date | Country | Kind |
---|---|---|---|
2009-071684 | Mar 2009 | JP | national |