Examination method of infection with Helicobacter pylori

Details Examination method of infection with Helicobacter pylori Examination method of infection with Helicobacter pylori

1995-04-18

2001-11-06

Gitomer, Ralph (Department: 1623)

Chemistry: molecular biology and microbiology

Measuring or testing process involving enzymes or...

Involving viable micro-organism

C435S012000

Reexamination Certificate

active

06312918

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a simple examination method of infection with
Helicobacter pylori
(hereinafter may also be abbreviated as “
H.p
.”) which is a bacillus and may present in gastric mucosa, and a device therefor. According to the invention, the information on
H.p
.-infection and the activity of
H.p
. at the time of examination can be easily obtained.
2. Related Arts
Because of the strongly acidic environment of the inside of the stomach, the gastric cavity had been considered unsuitable for the survival of bacilli since old times; however, about 100 years ago, the existence of spiral bacillus was observed and reported. The bacilli were formally discovered in the second half of the 1970's. In 1983, the bacilli were firstly isolated from gastric mucosa by Waren et al., and was named at first as “
Campylobacter pyloridis
, because it morphologically and biologically resembled Campylobacter which is one or
Salmonella enteritidis
, in addition to the fact that it was isolated from gastric antral mucosa in the vicinity of the pylorus. Later, the name was once changed to
Campylobacter pylori
. The genetic name has been changed to “Helicobacter” based on its form, since the difference from Campylobacter became clear in 1989.
Continuous effort has been made investigating the correlation between
H.p
. and diseases of the upper alimentary tract even since the bacilli were isolated at a high rate by Marshall et al. From patients with gastric ulcer, duodenal ulcer or chronic gastritis in 1984, and the association between the presence of the bacilli and these diseases has been reported [“The lancet”, No. 8390, pages 1311-1314 (June 1984)].
According to the subsequent study results, although the correlation has not been proved,
H.p
. are regarded as an important factor in the etiology of cancer of the stomach; therefore, the diagnosis of
H.p
.-infection has an important clinical significance to the treatment for the aforesaid diseases.
At the present time, such methods of examining
H.p
. as a microscopic examination method on gastric mucosa, a cultivation method of gastric mucosa tissue, and a rapid urease test on gastric mucosa tissue have been in the art, but all of the conventional methods need endoscopy which requires advanced technical skill or expertise and is too heavy a burden for patients; therefore, the clinical application of these methods is limited.
On the other hand, a method, which is now under consideration, for measuring anti-
H.p
. antibodies in blood or sputum cannot be applied for obtaining information on the present state of
H.p
.-infection, because of the time lag between
H.p
.-infection and appearance of the antibodies, or between
H.p
.-elimination and disappearance of the antibodies.
There is a
13
C-breath test as the method for obtaining informations on the present state of
H.p
.-infection without causing pain to the patients, but the clinical application thereof is also limited, because of the necessity of a radioisotope in combination with a large-sized and expensive apparatus, in addition to the inability of speeding up the operation of the apparatus in connection with the transportation of the specimen.
We have just found U.S. Pat. No. 4,947,861 (issued Aug. 14, 1990) disclosing a diagnosis of
H.p
. infection. In the patent specification (columns 2-4), Hamilton teaches a fact that ammonia could not be detected in expired alveolar air with a conventional apparatus, although the detection has been made based on theory that if urea is administered to a person infected with
H.p
., at least some portion of ammonia generated by the activity of
H.p
. is absorbed into the blood stream, passes through the liver without being broken down there, and is delivered to expired air at the alveoli of the lungs, but can be detected with the conventional apparatus, if a breath sample is treated by a desiccant material such as sodium hydroxide to absorb therein H
2
O and CO
2
in the sample breath and collect the dried breath, prior to the detection. however, he does not disclose any actual Example on diagnosis of
H.p
.-infection. We think this means that even if ammonia in the breath sample can be detected, an application of the method for the actual diagnosis is quite difficult or impossible from the view point of sensitivity, since almost all part of ammonia absorbed into the blood stream will be broken down by the liver and only a trace amount thereof shall appear in the breath sample, as stated also by him (line 24 in column 3).
OBJECT AND SUMMARY OF THE INVENTION
As described above, conventional methods of examining
H.p
.-infection have both advantages and disadvantages.
Therefore, a principal object of the invention is to provide a simple examination method of infection with
H.p
. without causing pain to the patients, wherein the method does not need a large-sized expensive apparatus, and informations on
H.p
.-infection and activity of
H.p
. can be obtained in situ.
A secondary but important object of the invention is to provide a simple device for examining
H.p.
It has been estimated that
H.p
. produce alkaline ammonia for neutralizing the gastric acid to make possible their survival in the strong acidic gastric cavity. Thus, on the basis of the recognition that
H.p
. have a high unit of urease which is specific to the production of ammonia and the produced ammonia shall present in high concentrations in the intragastric gas and gastric juice of
H.p
.-infected patients, the inventors have energetically studied and investigated to find out that there is a close correlation between the intragastric ammonia concentration and
H.p
.-infection, and by measuring the concentration, information on the present activity of
H.p
. at the time of examination can be obtained, so that the invention has been established.
The simple examination method of infection with
H.p
. according to the invention, therefore, comprises collecting a given amount, of gas in the gastric cavity, and then measuring primarily the ammonia and secondarily organic amines therein.
A number of ways have been presented in order to collect the intragastric gas; one is a method of collecting the gas directly by use of a cannula. However, the method cannot be conducted to collect the intragastric gas without causing pain to the subjects.
For the purpose of collecting the intragastric gas, it has now been found to be advantageous to lead the gas to the oral cavity with the aid of vomiting-reflexive belching, so-called “eructation” caused by the stimulation, for example, of the throat or the larynx.
It is preferable to administer an alkaline agent, urea preparation or hot water prior to the collection of the intragastric gas. The alkaline agent is used to facilitate the gasification of ammonia and organic amines, such as methyl amine, by reacting it with gastric acid. The urea preparation is used to produce ammonia in amounts correspond to the degree of
H.p
.-infection or the state of activity of
H.p
. by reacting it as substrate with urease which
H.p
. has, and the hot water (40-50° C. ) is used to increase the efficiency of gasification of ammonia by raising temperature in the gastric cavity.
Examples of the alkaline agents include sodium bicarbonate, precipitated calcium carbonate, magnesium oxide, magnesium carbonate, magnesium hydroxide, magnesium silicate, magnesium aluminate, aluminum silicate, aluminum hydroxide, magnesium meta-silicate aluminate, dimagnesium silicate aluminate, a co-precipitated composition comprising aluminum hydroxide/magnesium carbonate/calcium carbonate, and the like.
The gas collected from the gastric cavity is led to a sensor to measure total amount or ammonia and organic amines, because of that the gas consists primarily of ammonia, but organic amine gases shall possibly present therein, and the sensor detects the amines in addition to ammonia. Examples of such sensors include a gas detection tube (gas-detecting reagents in the tube changes in color by contacting with ammon

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