DE29902593U1 - Gas analyzer for medical diagnostics - Google Patents

Description

G 39 G 4

·

Keil&Schaafhausen

PATENT ATTORNEYS

Genzyme Virotech GmbH Löwenplatz

65428 Rüsselsheim

Gas analyzer for medical diagnostics

12.02.99

^{G 39 G 4} .; ··** ♦. .*

_ &igr; _ KEIL&SCHAAFHAUSEN

PATENT ATTORNEYS

Gas analyzer for medical diagnostics

The subject of the invention is a system for medical diagnostics containing gas sensors.

When examining body fluids for diagnostic purposes, it is still common to take a sample and analyze it at another location if necessary. This requires a lot of time and money, and the results of the examination are often only available after days. There is therefore a great need for diagnostic methods that can be used to obtain medical findings as quickly as possible, as directly as possible at the patient's bedside or in the specialist's office. Non-invasive methods are particularly desirable. The possibilities of making medical diagnoses through odor analysis have so far been little researched. Reliable statements about the type 5 of an illness by analyzing and identifying typical gas mixtures that body fluids, stool samples or body odors release in specific illnesses have so far been considered impossible.

There is therefore a need for a system that is able to quickly and reliably identify the gas mixtures that occur during an illness and to derive a medical diagnosis from this.

12.02.99

G 39 G 4

_ 2 - KEIL&SCHAAFHAUSEN

PATENT ATTORNEYS

Various devices have already been developed that are referred to as "electronic noses" and are used in quality control in the food industry, in the cosmetics or plastics industry, but also for monitoring in environmental technology, e.g. in the case of odor nuisances or in safety technology, e.g. for monitoring solvent storage facilities. Semiconductor gas sensors are used in such systems, which change their electrical resistance in the presence of gaseous compounds. Since the sensors are not identical, but differ in their semiconductors, their doping and operating temperatures, they provide different signals for different compounds in the gas phase. The detection limits of the sensors are in the upper ppb or lower ppm range. The signals provide a characteristic pattern that can be compared with previously stored patterns. The comparison and identification can then be carried out using neural networks. The electronic nose can therefore recognize previously learned compounds or substance mixtures.

In contrast to the human nose, the results are objective, i.e. they do not depend on the test person's mood or state of health. However, an electronic nose 5 does not smell exactly the same compounds as the human nose. For some substances, the odor threshold of the human nose is in the ppt-ppb range. However, there are also compounds for which the detection limit of the electronic nose is lower than that of the human nose. The intensity of the sensor signals is proportional to the concentration of the organic compounds in the air. Using olfactometric comparison measurements, a scaling in odor units can be carried out if the composition of the odorous substances is constant.

12.02.99

G 39 G 4 . ...i

_ 3 - KEIL&SCHAAFHAUSEN

PATENT ATTORNEYS

Gas mixtures often consist of complicated mixtures of different gaseous substances that cannot be detected in their entirety by a single gas sensor. Using suitable combinations of semiconductor gas sensors, signal patterns can be detected and the gas mixtures identified. It can be assumed that every smell occurring in nature can be understood as a linear combination of a limited number of smells, the so-called "primary smells" (2). Primary smells are not chemical substances, but rather classes of substances that have certain smell properties. The gas sensors used are therefore not selectively aimed at a single chemical substance, but rather, depending on the gas sensor, entire classes of substances are detected in the gas to be examined.

When analyzing natural odors, the gas sensors used to detect primary odors are combined to form a system of different semiconductor gas sensors (=array). The gas sensors used in the sensor array generate signal patterns that are interpreted by comparing them with the patterns of the primary odors. The evaluation is conveniently done graphically. Different primary odors produce different forms of signal patterns (fingerprints). These signal patterns can be distinguished by the human sense organs as well as by a computer. The combination of sensor array and computer analysis enables reliable detection of the individual primary odors.

0 They can be reproduced perfectly and compared with the

odor.

A gas analyzer for medical diagnostics has now been developed that is equipped with gas sensors to detect gaseous substances that can be produced by a disease.

12.02.99

^{G 39 G 4}

- 4 - KEIL&SCHAAFHAUSEN

PATENT ATTORNEYS

detect characteristic gaseous substances released from solid, liquid or gaseous body excretions or from cultures of pathogens or parasites and convert them into signal patterns which are compared with the characteristic signal patterns of gaseous substances produced by pathogens or parasites in known diseases previously stored in a database and identified, thus enabling a medical diagnosis.

It is known that many diseases caused by pathogens give rise to body odors or odors from body secretions that are typical for the type of disease. For example, in the case of an infection with Mycoplasma hominis, a fishy odor can be detected in the patient (3), while in the case of bacterial vaginosis, for example, a characteristic amine odor occurs (4).

Pathogenic agents 0 grown on nutrient media and cultures often form a characteristic pattern of gaseous substances that can be used for their unambiguous identification.

Basically, it is possible to record the smells that occur in various diseases in the form of signal patterns (fingerprints) and store them in a computer or in another way, for example. These signal patterns can then be compared with the smell pattern that occurs in an unknown disease and thus be used for medical diagnostics immediately, reliably and quickly without the use of invasive methods.

This new diagnostic option, also known as olfactometric pathogen diagnostics, for which portable, computer-controlled complete systems are available, can be used in

12.02.99

- 5 - Keil&Schaafhausen

PATENT ATTORNEYS

can be easily carried out at the bedside or in the doctor's office.

An example of the medical use of a system consisting of semiconductor gas sensors for identifying odors can be seen in the breath test for detecting Helicobacter pylori. This test is known to be carried out using C ¹³ -labeled urea, which the patient takes orally in a drinking solution. In the presence of Helicobacter pylori, the C ¹³ -labeled urea is hydrolyzed to ammonia and C ¹³ O ₂ . The latter can be detected in the breath using a sensitive isotope ratio mass spectrometer. However, this requires that the breath sample containers are sent to a qualified analysis laboratory and examined there.

In order to diagnose an infection with Helicobacter pylori, a gas analyzer has been developed according to the invention, which is equipped with gas sensors that detect the ammonia present in the breath when the breath test is carried out and convert it into a corresponding signal pattern, which is compared with the signal pattern of ammonia previously stored in a database and thus enables a diagnosis of a possible infection with Helicobacter pylori.

This makes it much easier and quicker than before to detect the odorous ammonia in the exhaled air or stomach air instead of the labeled carbon dioxide. Ammonia produces a characteristic signal pattern that is easily recognizable by the electronic nose. If this signal pattern is found in the smell of the exhaled air or stomach air, it can be concluded with certainty that Helicobacter pylori is present.

12.02.99

39 G 4 , ....

KEIL & SCHAAFHAUSEN

PATENT ATTORNEYS

Lactose intolerance cannot be diagnosed using traditional internal examination methods (laboratory tests, sonography, endoscopy). As a result, this disorder is still often overlooked today and the symptoms are considered to be caused by nerves in the broadest sense. However, this disease can be easily diagnosed using a system containing gas sensors. The evidence is based on the fact that lactose intolerance is caused by a lack of an enzyme in the mucous membrane of the small intestine, lactase, which breaks down lactose into its components glucose and galactose. After consuming lactose, for example after consuming dairy products, the affected patients suffer from painful symptoms such as flatulence, abdominal pain or diarrhea because the lactose cannot be absorbed by the small intestine and is fermented by bacteria in the large intestine, producing hydrogen. According to the invention, this hydrogen can be detected in the breath and thus allows a diagnosis of lactose intolerance.

For this purpose, a gas analyzer according to the invention has been developed which is equipped with gas sensors for diagnosing lactose intolerance, which detect the hydrogen contained in the breath and convert it into a corresponding signal pattern, which is compared with the signal pattern of hydrogen previously stored in a database and thus enables a diagnosis of any lactose intolerance.

In the same way, other enzyme deficiencies can be detected that result in the release of gaseous substances in body fluids or body excretions. This also applies to the detection of parasite infestation or the detection of bacterial or viral infections that are caused by the

12.02.99

39 ,

_ 7 - KEIL&SCHAAFHAUSEN

PATENT ATTORNEYS

Release of gaseous substances in body fluids or body excretions.

For this purpose, according to the invention, a gas analyzer is provided which is equipped with gas sensors which detect the gaseous substances formed from body fluids or body excretions or from corresponding cultures of microorganisms in the event of enzyme deficiencies, bacterial or viral infections or parasite infestations and convert them into a signal pattern which is compared with the signal pattern previously stored in a database and thus enables a diagnosis.

The use of the electronic nose according to the invention makes it possible to identify gaseous substances that are released from solid, liquid or gaseous body excretions or from cultures of pathogenic organisms in the event of illness. This creates a new medical diagnostic option that enables a rapid and reliable diagnosis of a wide range of illnesses in the most gentle way possible.

12.02.99

39 G4

- 8 - KEIL& SCHAAFHAUSEN

PATENT ATTORNEYS

Bibliography :

(1) T. Tarn, Q. Lucas, L. Moy, J.W. Gardener, P. Bartlett, The Electronic Nose - A New Instrument for Sensing Vapours, LC-GC INT. Vol. 8, November.4 (1995) 218-225

(2) J.E. Amoore, Nature 214, 1095 (1967) 10

(3) Am. J. of Obstetrics and Gynecology; 176; 1 Pt1; 173-8; 1997 Jan; 9705

(4) Pathology Biology; 42; 5; 539-543; 1994May, 9504

12.02.99

Claims (1)

G 39 G 4 _ 9 _ KEIL&SCHAAFHAUSEN PATENT ATTORNEYS Protection claims: 1. Gas analyzer for medical diagnostics, characterized in that it is equipped with gas sensors for the detection of gaseous substances, which detect the characteristic gaseous substances released from solid, liquid or gaseous body excretions or from cultures of pathogenic agents or parasites during an illness and convert them into signal patterns which are compared with the characteristic signal patterns previously stored in a database of gaseous substances produced by pathogenic agents or parasites in known illnesses and are identified, thus enabling a medical diagnosis. 2. Gas analyzer according to claim 1, characterized in that it is equipped with gas sensors for diagnosing an infection with Helicobacter pylori, which detect the ammonia present in the breath when the breath test is carried out and convert it into a corresponding signal pattern, which is compared with the signal pattern of ammonia previously stored in a database and thus enables a diagnosis of a possible infection with Helicobacter pylori. 3. Gas analyzer according to claim 1, characterized in that it is equipped with gas sensors for diagnosing lactose intolerance, which detect the hydrogen contained in the breath and convert it into a corresponding signal pattern, which is compared with the signal pattern of hydrogen previously stored in a database and thus enables a diagnosis of any lactose intolerance. 12.02.99 G 39 G 4 _ 10 - KEIL&SCHAAFHAUSEN patent attorneys 4. Gas analyzer according to claim 1, characterized in that it is equipped with gas sensors which detect the gaseous substances formed from body fluids or body excretions or from corresponding cultures of microorganisms in the event of enzyme deficiencies, bacterial or viral infections or parasite infestations and convert them into a signal pattern which is compared with the signal patterns previously stored in a database and thus enables a diagnosis. 12.02.99