Surgery – Diagnostic testing – Measuring or detecting nonradioactive constituent of body...
Reexamination Certificate
1999-03-11
2001-03-06
Winakur, Eric F. (Department: 3736)
Surgery
Diagnostic testing
Measuring or detecting nonradioactive constituent of body...
C600S341000, C600S364000, C128S903000
Reexamination Certificate
active
06198950
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to implantable diagnostic apparatuses for determining analytes and methods for their use.
BACKGROUND
Implantable diagnostic apparatuses have already been described, for example, as parts of implantable insulin pumps. Such apparatuses essentially comprise an implantable measurement chamber in which a biosensor generates an analyte-dependent signal which, for its part, serves to control the insulin pump. These apparatuses have to be exchanged periodically when the insulin reserve is exhausted. Since this exchange takes place relatively frequently, the exchange interval is frequently shorter than the service life of the biosensors.
What is disadvantageous in the case of previous methods, and probably also a reason why the previous methods for glucose determination in connection with insulin pumps have not been applied to other parameters, is the problem that would arise if the biosensors are in contact with blood over a relatively long period of time and then their function is impaired, or even rendered impossible, by deposits such as, for example, fat- or protein-containing deposits (clots).
In particular, methods for determining coagulation parameters, which, by their nature, are often associated with clot formation, are not considered to be promising.
The object underlying the present invention is to provide an implantable diagnostic apparatus which enables the intervals between the exchanges of the apparatuses to be significantly lengthened and which allows the detection of coagulation and fibrinolysis parameters to determine hemostasis disturbances, e.g. by detecting factor VIII or measuring the PT (prothrombin) time.
It has been found, surprisingly, that the apparatus according to the invention, either as an individual measurement chamber or as an apparatus containing a plurality of measurement chambers, can advantageously be used to determine hemostasis disturbances, i.e. any malfunction of the hemostasis system.
SUMMARY OF THE INVENTION
The present invention relates to a diagnostic apparatus for determining analytes, which comprises at least (i) one measurement unit for single or continuous determination of an analyte, wherein the measurement unit generates a signal in the presence of the analyte to be determined; (ii) a signal transmission unit capable of converting that signal and capable of forwarding it to a signal-processing unit or forwarding the unconverted signal to a signal-processing unit; and (iii) a sample feeder to the measurement unit(s) which extends into the relevant liquid-containing body compartment, for instance a blood vessel. A light source which radiates a light suitable for exciting photosensitizers, preferably such as those as disclosed in EP-A2-0 515 194 (incorporated herein by reference), projects into the measurement chamber of said measurement unit. The surface within the measurement chamber shall be at least partly conductive or alternatively, the measurement chamber shall contain a light receiver. The measurement chamber preferably contains photosensitizers, especially photosensitizers incorporated into so-called sensitizer beads, capable of producing oxygen radicals after illumination. The analytes to be determined react with photosensitizers in such a way that the photosensitizers yield, depending on the analyte's concentration or activity, singlet oxygen which is measured by electrodes and converted into a transmittable signal. Alternatively, the signal is generated in the presence of analytes by photosensitizers that are in close proximity with acceptors, which might be incorporated into so-called acceptor beads, and the singlet oxygen generated by the photosensitizers activates said acceptors which subsequently produce light, and said light is detected. Acceptors preferably comprise substances such as described as a chemiluminescent compound in EP-A2-0 515 194.
The present invention relates fither to methods for determining analytes or their activity, preferably for the detection of hemostatsis disturbances, comprising an diagnostic apparatus as described above (i) wherein the analytes react with photosensitizers in such a way that the photosensitizers yield, depending on the analyte's concentration or activity, singlet oxygen which is measured by electrodes and converted into a transmittable signal; or (ii) wherein in the presence of analytes the signal is generated by photosensitizers that are in close proximity with acceptors and the singlet oxygen generated by the photosensitizers activates said acceptors which subsequently produce light, and said light is detected.
REFERENCES:
patent: 4759371 (1988-07-01), Franetzki
patent: 5109850 (1992-05-01), Blanco et al.
patent: 5616719 (1997-04-01), Davalian et al.
patent: 6049727 (2000-04-01), Crothall
patent: 0 515 194 A2 (1992-11-01), None
Dade Behring Marburg GmbH
Finnegan, Henderson Farabow, Garrett and Dunner L.L.P.
Winakur Eric F.
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