Combined spectroscopic and biochemical measurements were used to improve diagnostic accuracy and to evaluate gastrointestinal tract (GIT) neoplasia development parameters noninvasively. Experiments were performed in mongrel male rats divided into 2 groups – control and experimental. To induce gastric cancer, the rats underwent to chronic stress (overpopulation during 9 months) and diet including the daily using of mtoluidine (25 μg/kg weight) in food and water with a solution of sodium nitrite (0.2%) for 9 months. We studied effectiveness of 5-ALA/PpIX fluorescent analysis of gastric carcinoma and biochemical stress-corresponding indices detection for early diagnosis of primary gastric tumours and their metastatic spreading in liver. Affected by precancerous and cancerous alterations mucosa reveal red fluorescence, related to the accumulation of 5- ALA/PpIX. Liver tissues investigated also presented increase of the red fluorescence, which was used as an indicator for possible pathologic process detection there. The histological examination revealed liver metastases in 67.8 % of the rats with gastric cancer. Biochemical indicators detected malignant alterations presence in GIT, and fluorescent observation addressed the exact area and borders of neoplastic lesions. 5-ALA/PpIX fluorescence detection allow to find and precisely map premalignant and malignant areas of gastric mucosa and liver metastases of stress-induced gastric heterogeneous adenocarcinoma and biochemical evaluation of stressrelated compounds increased the efficiency of such diagnosis and reveal information about the dynamics of lesions development. Diagnostic accuracy achieved using fluorescent detection reaches 93% for gastric carcinoma, and 87% for pre-cancerous mucosa alterations observed.
Gastrointestinal cancerous lesions were induced in laboratorial animals using prolonged exposure to social (overpopulation) and chemical stress (nitrosamine diet), mimicking typical stress factors for humans in the big cities. Twenty laboratorial rats with developed stress-induced neoplasia in gastrointestinal tract were used. Three of them formed control group - without application of exogenous contrast fluorescent marker. Exogenous fluorescent spectroscopic measurements were used to evaluate gastrointestinal tract (GIT) neoplasia development noninvasively using excitation at 405 nm and emission was detected in the region of 500-850 nm using microspectrometer. We used as exogenous fluorescent marker protoporphyrin IX applying its precursor delta aminolevulinic acid in a dose of 20mg/kg, in laboratorial rats with stress-induced neoplasia. Spectroscopic analysis of primary gastric tumours and their metastases spreading in rats’ liver was carried out on animals in vivo, as excitation and emission light were delivered by fiberoptic probe 6+1 to the organs investigated during open surgery procedure. Biochemical indicators detected malignant alterations presence in GIT were also evaluated and used as complementary indices for lesions’ growth. Fluorescent observation using exogenous fluorophore addressed the exact area and borders of neoplastic lesions in stomach and liver. In some cases in inflammatory areas significant accumulation of delta-ALA had place, which lead to false-positive fluorescent signal of protoporphyrin IX in these tissues. Photodiagnostics accuracy of 93% was reached for cancerous cases and 87% for gastric pre-cancer lesions evaluation. Very good correlation between fluorescence data and histology examination of the lesions investigated was achieved as well.
We obtained impedance dispersion curves of stomach and liver tissues of rats in dynamics, while affecting with tumorigenic inductors: sodium nitrite (0.2%) and m-toluidine (25 mg per 1 kg body weight) in chronic experiment (over 10 months) in male outbred white rats aged 3 and 14 months at the beginning of the experiment. A substantial decrease in the impedance values for all test frequencies (50 Hz to 1 MHz) was shown.
It was shown in the experience with 60 white mice that separate and combined effects of stress factors: noctidial lighting (800 lux), sodium nitrite (0.2% solution in water) and p-toluidine (with food) within 107 days causes a change in impedance value of erythrocytes at frequencies 1 Hz – 1MHz. Changes in the activity of intracellular aminotransferases, creatinine and urea were observed, indicating cardiotoxic and hepatotoxic effects.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.