The Novel Diagnostic Index Based on HLA-DRB1 Genotype and PD-L1 Expression can Predict Severe irAEs in Patients with Metastatic Melanoma Taking Immune Checkpoint Inhibitors. The Results of the Pilot Study.

Immune-related adverse events (irAEs) occur in up to 50% of patients treated with an anti-CTLA-4 antibody and 30% of patients treated with PD-1/PD-L1 antibodies. Severe forms of toxicity are observed in 3% of patients and require systemic steroid therapy and constant monitoring. One of the considered predictor biomarkers of irAEs development is HLA-genotypes. This research aims to evaluate the diagnostic significance of HLA-DRB1 genotypes and other clinical and laboratory parameters to predict the development of irAEs. The study involved 28 patients with metastatic melanoma taking checkpoint inhibitors therapy [nivo 53.6%, Ipi+nivo 32.1%, other (pembro, prolgo) 14.3%]. The PD-L1 expression and HLA-DRB1 genotype were evaluated. After 2-3 months the development of irAES was assessed. The complications of 3-4 grade or multi-organ damage were termed as severe irAEs. Various IrAEs developed in 57.1% (16/28) of patients, while severe irAEs occurred in 35.7% (10/28). Among all patients, HLA-DRB1 genotypes associated with the risk of autoimmune diseases were found in 78.5% (22/28). The PD-L1 expression was detected in 60.7% (17/28) of individuals. Combination treatment increases the risk of toxicity, p = 0.0028, with a diagnostic sensitivity of 56% and a diagnostic specificity of 100% (RR = 2.71, OR = 31.67). An index based on the parameters studied (HLA-DRB1, absence of PD-L1 expression, and type of treatment) was created. It allows assuming the risk of developing severe irAES (p = 0.0126). When comparing this indicator between irAEs 1-2 and irAEs 3-4, the presence of an index value of more than 2 gives a sensitivity for predicting severe toxicity of 40.00% and a specificity of 83.33%.

Modeling of Benign Prostatic Hyperplasia in Rats with a High Dose of Testosterone.

In order to optimize the testosterone model of benign prostatic hyperplasia, we studied the effect of castration and different doses of testosterone on the induction of the proliferative process in the prostate of Wistar rats. It was shown that 4-week subcutaneous administration of testosterone propionate in a dose of 20 mg/kg causes pronounced proliferative and hemodynamic disorders in the dorsolateral gland morphologically similar in castrated and non-castrated males. Administration of testosterone in a dose of 3 mg/kg had no significant effect on the dynamics of the pathological process in non-operated rats and normalized the structure of the gland in castrated animals. Morphological study showed that castration of males provides no visible advantages in reproducing the testosterone model of benign prostatic hyperplasia. The proposed non-traumatic modification of the model with a high dose of testosterone has good reproducibility and sensitivity to therapeutic agents, as shown by the example of finasteride.

[The assessment of physical fitness level, the functional status and the social features of the elderly that decided to engage in physical exercises.]

For the sake of maintaining active longevity of the elderly the adequate, individually selected physical activity, that was get after the integrated assessment of physical fitness level, the functional status and the social features, is necessary. 121 women (mean age 66,77±5,37) who decided to engage in physical exercises were included in the study. For every participant professional, social and sport anamnesis, the presence of illnesses, the clinical information and the functional tests (Stange, orthostatic, «6 minutes walking¼, «Up and go¼) were evaluated. Was get, that 75,21% participants of the study had hypertension. The normal type of systolic blood pressure reaction during orthostatic test was present in 71,07% people, by diastolic blood pressure - in 84,29% people. The body mass index corresponded to the excess body weight. The indices of the grip strength, spirometry were decreased, but were not critical. The indices of the grip right and left arm correlated with age (R=0,33; p<0,01; R=0,31; p<0,01). The results of the tests «Up and Go¼ and «6 minutes walking¼ were evaluated as normal. The orthopedic examination has revealed the flatfoot and scoliosis. 91,73% of the retired individuals did not have a job. Cause of retirement for the majority of patients were stuff cuts after the age 60, which was not in accordance with the satisfactory physical state of the participants of the investigation. Therefore, nowadays the questions of part-time employment of the elderly and re-education of the people with the age «50+¼, together with the development of physical exercise programs are of great importance.

[Factors associated with an increase in spatial and frontal QRS-T angles in patients with anterior myocardial infarction].

Aim    To determine existence of a relationship between any clinical, echocardiographic and coronarographic factors and increased spatial QRS-T (sQRS-T) angle and frontal QRS-T (fQRS-T) angle in patients with anterior myocardial infarction.Material and methods    This study included 137 patients aged 62 [53; 72] years with anterior acute myocardial infarction managed at the A.L. Myasnikov Institute of Clinical Cardiology. fQRS-T was calculated as the module of difference between the frontal plane QRS complex axis and the T wave axis. sQRS-T was calculated as a spatial angle between QRS and T integral vectors from a synthesized vectorcardiogram.Results    fQRS-T values for a group (median [25th; 75th percentile]) were 81 [37; 120]°; sQRS-T values were 114 [80; 141]°. The correlation coefficient between fQRS-T and sQRS-T values was 0.41 (p<0.001). fQRS-T weakly but statistically significantly correlated with patients' age (r=0.28; p=0.001), left ventricular ejection fraction (LV EF, r= -0.22; p=0.01), and glomerular filtration rate (r=-0.32; p=0.0002). sQRS-T weakly but statistically significantly correlated with left ventricular end-diastolic dimension (r=0.24; p=0.0048), LV EF (r=-0.28; p=0.0009), and the number of affected segments according to echocardiography data (r=0.27; p=0.002). fQRS-T values were significantly higher in the presence of concurrent arterial hypertension. sQRS-T values were significantly higher in the presence of a history of chronic heart failure. Both fQRS-T and sQRS-T values increased with increasing number of affected blood vessels and Killip class of acute heart failure.Conclusion    In patients after anterior acute myocardial infarction, increases in fQRS-T and sQRS-T are associated with more severe damage of the vasculature, decreased LV EF, and, thus, more severe clinical course of disease.

[Computed Tomography Coronary Angiography Possibilities in "High Risk" Plaque Identification in Patients with non-ST-Elevation Acute Coronary Syndrome: Comparison with Intravascular Ultrasound].

Aim      To evaluate structural characteristics of atherosclerotic plaques (ASP) by coronary computed tomography arteriography (CCTA) and intravascular ultrasound (IVUS).Material and methods  This study included 37 patients with acute coronary syndrome (ACS). 64-detector-row CCTA, coronarography, and grayscale IVUS were performed prior to coronary stenting. The ASP length and burden, remodeling index (RI), and known CT signs of unstable ASP (presence of dot calcification, positive remodeling of the artery in the ASP area, irregular plaque contour, presence of a peripheral high-density ring and a low-density patch in the ASP). The ASP type and signs of rupture or thrombosis were determined by IVUS.Results The IVUS study revealed 45 unstable ASP (UASP), including 25 UASP with rupture and 20 thin-cap fibroatheromas (TCFA), and 13 stable ASP (SASP). No significant differences were found between distribution of TCFA and ASP with rupture among symptom-associated plaques (SAP, n=28) and non-symptom-associated plaques (NSAP, n=30). They were found in 82.1 and 73.3 % of cases, respectively (p>0.05), which indicated generalization of the ASP destabilization process in the coronary circulation. However, the incidence of mural thrombus was higher for SAP (53.5 and 16.6 % of ASP, respectively; p<0.001). There was no difference between UASP and SASP in the incidence of qualitative ASP characteristics or in values of quantitative ASP characteristics, including known signs of instability, except for the irregular contour, which was observed in 92.9 % of UASP and 46.1 % of SASP (p=0.0007), and patches with X-ray density ≤46 HU, which were detected in 83.3 % of UASP and 46.1 % of SASP (р=0.01). The presence of these CT criteria 11- and 7-fold increased the likelihood of unstable ASP (odd ratio (OR), 11.1 at 95 % confidence interval (CI), from 2.24 to 55.33 and OR, 7.0 at 95 % CI, from 5.63 to 8.37 for the former and the latter criterion, respectively).Conclusion      According to IVUS data, two X-ray signs are most characteristic for UASP, the irregular contour and a patch with X-ray density ≤46 HU. The presence of these signs 11- and 7-fold, respectively, increases the likelihood of unstable ASP.

Computed Tomography Myocardial Perfusion Imaging With Transesophageal Atrial Pacing Stress Test in Patients With Borderline Stenoses in the Coronary Arteries: a Comparison With Fractional Flow Reserve.

Aim      To evaluate the diagnostic accuracy of cardiac perfusion computed tomography (PCT) with transesophageal electrocardiostimulation (TE ECS) for detection of ischemia in patients with borderline coronary stenosis (50-75 %) compared to measurements of fractional flow reserve (FFR).Material and methods  The study included 25 patients with borderline (50-75 %) coronary stenosis as per data of computed tomography angiography (CTA) or coronary angiography (CAG). Later the patients underwent invasive measurement of FFR and cardiac PCT on a 320-row detector tomograph in combination with the TE ECS stress test.  FFR values <0.8 indicated the hemodynamic significance of stenosis. Myocardial perfusion was evaluated visually based on consensus of two experts.Results All patients completed the study protocol. Cardiac pacing duration was 6 min for all patients. Four patients required intravenous administration of atropine sulphate. PCT with TE ECS detected significant for FFR stenoses with sensitivity, specificity, and predictive value of a positive result and predictive value for a negative result of 47, 90, 87, and 53 %, respectively.Conclusion      PCT with TE ECS in combination with CTA can be considered as an informative method for simultaneous evaluation of the condition of coronary arteries and detection of myocardial ischemia. This method is particularly relevant for assessing the hemodynamic significance of borderline coronary stenoses.

Prostatotropic Action of Glycyrrhizic Acid Disodium Salt in Benign Prostatic Hyperplasia Models.

The prostatotropic activity of glycyrrhizic acid disodium salt (Na2GA) was studied in the models of benign prostatic hyperplasia (BPH) induced by chronic injection of sulpiride (40 mg/kg intraperitoneally for 8 weeks) or testosterone propionate (20 mg/kg subcutaneously for 4 weeks) in the Wistar rats. The oral administration of Na2GA in a dose of 100 mg/kg produced a moderate antiproliferative effect in both BPH models resulting in reduced volume density of prostatic epithelium (in the testosterone model) and increased volume density of the glandular lumen (in both models). The observed prostatotropic effects of Na2GA were similar to those of Permixon and finasteride, but they were less pronounced as confirmed by smaller drops in epithelial volume density and epithelial-to-stromal ratio compared to the effects of both reference drugs.

[Factors Associated with the Increase in Spatial and Frontal QRS-T Angles in Patients with Inferior Myocardial Infarction].

Aim      To identify clinical, echocardiographic, and angiographic factors related with an increase in the frontal QRS-T angle (fQRS-T) and the spatial QRS-T angle (sQRS-T) in patients with inferior myocardial infarction.Material and methods  The study included 128 patients aged (median [25th percentile; 75th percentile]) 59.5 [51.5; 67.0] years diagnosed with inferior wall acute myocardial infarction. fQRS-T was calculated as a module of difference between the QRS axis and the Т axis in the frontal plane. sQRS-T was calculated by a synthesized vectorcardiogram as a spatial angle between the QRS and Т integral vectors.Results The fQRS-T for the group was 54.0 [18; 80] and sQRS-T was 80.1 [53; 110]. The correlation coefficient for fQRS-T and sQRS-T values was 0.42 (p<0.001). Both fQRS-T >80° and sQRS-T >110° compared to their lower values were associated with a higher frequency of history of postinfarction cardiosclerosis (44% and 12 %, respectively; p<0.05), a lower left ventricular ejection fraction (51 [47; 60]% at fQRS-T >80° and 55 [50; 60]% at fQRS-T <80° (p<0,05); 49 [44; 57]% at sQRS-T >110° and 57 [51; 60] % at sQRS-T <110° (p<0.01); more frequent development of acute heart failure (16 and 2 %, respectively; p<0.05); and early postinfarction angina (13 and 2 %, respectively; p<0.05). The increased fQRS-T was associated with a higher incidence of damage to the circumflex artery (45 and 20 %, respectively; p<0.05). The increased sQRS-T was associated with a history of arterial hypertension (97 and 76 %, respectively; p<0.05), chronic heart failure (22 and 3 %, respectively; p<0.05), chronic kidney disease (19 and 4 %, respectively; p<0.05), and a larger myocardial lesion (mean number of damaged segments by echocardiography was 3.8 [2; 6] at sQRS-T >110° and 2.6 [1; 4] at sQRS-T <110°; p<0.01). sQRS-T was significantly greater in multivascular damage (87 [68; 121]° than in one- or two-vascular damage (72 [51; 100]°; p<0.05). sQRS-T values were significantly lower with spontaneous reperfusion (66 [29; 79] than without spontaneous reperfusion (77 [55; 115]°; p<0.05).Conclusion      In patients after inferior wall acute myocardial infarction, increases in fQRS-T and sQRS-T were associated with more severe damage of coronary vasculature, decreased left ventricular ejection fraction, and more severe course of disease.

[Possibilities of Stress Computed Tomography Myocardial Perfusion Imaging in the Diagnosis of Ischemic Heart Disease].

Computed tomography angiography (CT-angiography, CTA) allows noninvasive visualization of coronary arteries (CA). This method is highly sensitive in detecting coronary atherosclerosis. However, standard CTA does not allow evaluation of the hemodynamic significance of found CA stenoses, which requires additional functional tests for detection of myocardial ischemia. This review focuses on possibilities of clinical use, limitations, technical aspects, and prospects of a combination of CT-angiography and CT myocardial perfusion imaging in diagnostics of ischemic heart disease.

Morphological Assessment of Prostatotropic Activity of (3,5-Dimethyl-4-Hydroxy)Benzyl Thiododecane on a Model of Benign Prostatic Hyperplasia in Rats.

Prostatotropic activity of (3,5-dimethyl-4-hydroxy)benzyl thiododecane (T-DD) was evaluated on a model of benign prostatic hyperplasia induced in Wistar rats by chronic (2 months) intraperitoneal administration of sulpiride (40 mg/kg). Morphometric analysis of the dorsolateral lobe of the prostate showed that after the 2-month course of intragastric T-DD (100 mg/kg) administered in parallel with sulpiride, the volume density of glandular epithelium decreased by 1.7 times, while the volume density of prostate stroma increased by 2 times. After administration of the reference drug Permixon at a dose of 50 mg/kg, the volume densities of epithelium decreased by 1.3 times and stromal volume density increased by 1.5 times. The observed effects are presumably related to suppression of 5α-reductase activity and modulation of estrogen receptors in the prostate.

[Spontaneous Coronary Artery Dissection].

During several recent decades spontaneous coronary artery dissection (SCAD) has been known as one of causes of development of acute coronary syndrome (ACS). It has been assumed that this condition is extremely rarely met and is associated with pregnancy and postpartum period. The use in clinical practice of high sensitivity troponin, coronary angiography (CAG) in early period of ACS, in conjunction with the growing awareness of doctors about this pathology led to a revision of the viewse on prevalence of the disease. At present SCAD is considered as one of the causes of ACS in young and middle-aged women. In this review we present results of studies of pathogenesis, diagnostics, and treatment of SCAD, describe various angiographic types of this disease, and discuss problems of choice of optimal strategy of management of patients with SCAD.

[Endovascular closure of a ventricular septal defect from Takotsubo Syndrome].

Takotsubo Syndrome is a transient condition characterized by left ventricular systolic dysfunction. Although the prognosis is excellent in most cases, rare cases of serious complications can occur. We present a case of a 81-year - old woman with Takotsubo Syndrome complicated by ventricular septal rupture that was successfully closed with an occluder Occlutech with good immediate and long - term outcomes.

Analysis of Gut Microbiota in Patients with Parkinson's Disease.

Gut microbiota of patients with Parkinson's disease and healthy volunteers was analyzed by the method of high throughput 16S rRNA sequencing of bacterial genomes. In patients with Parkinson's diseases, changes in the content of 9 genera and 15 species of microorganisms were revealed: reduced content of Dorea, Bacteroides, Prevotella, Faecalibacterium, Bacteroides massiliensis, Stoquefichus massiliensis, Bacteroides coprocola, Blautia glucerasea, Dorea longicatena, Bacteroides dorei, Bacteroides plebeus, Prevotella copri, Coprococcus eutactus, and Ruminococcus callidus, and increased content of Christensenella, Catabacter, Lactobacillus, Oscillospira, Bifidobacterium, Christensenella minuta, Catabacter hongkongensis, Lactobacillus mucosae, Ruminococcus bromii, and Papillibacter cinnamivorans. This microbiological pattern of gut microflora can trigger local inflammation followed by aggregation of α-synuclein and generation of Lewy bodies.

Specific Features of Progression of the Parasitic Invasion, caused by Opisthorchis felineus, in Golden Hamsters.

The influence of Opisthorchis felineus invasion on the development of pathological changes in the hepatobiliary system was studied in 120 golden hamsters in a long-term experiment (42 weeks) after single infection per os in the dose of 50 metacercariae per animal. The animals were sacrificed on weeks 4, 8, 12, 16, 28 and 42. Chronic experimental infestation with O. felineus triggered a cascade of morphogenetic processes in both extrahepatic and intrahepatic biliary systems. At the early stages of the experiment, polyps and strictures of bile ducts were formed in the lobar bile ducts; in portal tracts, hyperplasia and adenomatous transformation of the newly formed epithelial structures were observed. At the later stages, third-degree biliary intraepithelial neoplasia developed in the lobar bile ducts; in the intrahepatic bile ducts, increased epitheliocyte hyperplasia and invasive growth of cell cords were observed, that impaired tissue architectonics. Progressing cell atypia can be classified as cholangiocellular cancer.

[Correlation Between Emotional-Affective Disorders and Gut Microbiota Composition in Patients with Parkinson's Disease].

Background: Despite the efforts of scientific community the data available on the correlation between emotional-affective symptoms of Parkinson's disease and changes in microbiome is still scarce. Deeper studies of nonmotor symptoms evident in premotor stages of the disease and the reciprocal influence of microbiota may help to understand the etiology and pathogenesis of PD neurodegeneration better. Aim of the Study: Discover the relations between emotional-affective disorders prevalent in PD population and changes in gut microbiota composition. Methods: 51 patient diagnosed with PD participated in the study. Every participant's emotional-affective state was examined using Beck's Depression Inventory (BDI) and Hospital Anxiety and Depression Scale (HADS). Taxonomic richness of microbiome was studied using 16S ribosomal RNA gene sequencing, bioinformatics, and statistical analysis. Results: Anxiety and depression are prevalent affective disorders in patients with PD. In our study, most of the subjects demonstrated certain anxiety and depression. Taxonomic diversity of gut microbiota in BP was increasing with the increase in anxiety levels, reaching the maximum in the group with subclinical anxiety, and decreasing in the group with clinically significant anxiety disorder. At the species level, patients with clinically significant anxiety had higher abundance of Clostridium clariflavum compared to the anxiety-free patients. Patients with moderate depression were characterized by the higher prevalence of Christensenella minuta, Clostridium disporicum, and Oscillibacter valericigenes compared to subjects without depression or with mild depression. Conclusion: The data we received in our study allow better understanding of PD pathogenesis.

[Blood fatty acids in the development and correction of metabolic syndrome]. / Zhirnye kisloty krovi v formirovanii i korrektsii metabolicheskogo sindroma.

AIM: to investigate the composition of plasma fatty acids (FA) and red blood cells and the level of eicosanoids in patients with metabolic syndrome (MS) and to assess whether metabolic disturbances may be corrected during a cycle use of an ω-3 polyunsaturated fatty acid (PUFA). SUBJECTS AND METHODS: Examinations were made in 46 patients, including Group 1 (a control group) of 15 persons without MS components; Group 2 of 31 patients with MS, Group 3 of 16 MS patients who had taken an ω-3 PUFA for 6 months, and Group 4 of 15 MS patients who had received the drug for 12 months. The composition of plasma FA and red blood cells was analyzed on a gas-liquid chromatograph. An enzyme immunoassay was used to measure the serum levels of tumor necrosis factor-α (TNF-α) and eicosanoids (thromboxane B2, 6-keto-prostaglandin F1α, leukotriene B4). A biologically active additive from the king crab (Paralithodes camtschatica) hepatopancreas was used as a source of ω-3 PUFA. RESULTS: Having a higher proportion of linoleic and α-linolenic acids in the plasma, the patients were found to have decreased levels of ω-3 and ω-6 PUFAs (linoleic and α-linolenic, arachidonic, and eicosapentaenoic acids) and a larger proportion of Mead acid and saturated FAs (myristic and stearic acids) in the red blood cells, suggesting that that cellular blood FA transfer was impaired and FAs were absorbed by cells. Their serum samples showed the high levels of leukotriene B4, 6-keto-prostaglandin F1α, and thromboxane A2. The long-term (6- and 12-month) use of ω-3 PUFA from the king crab hepatopancreas had a positive impact in modifying the lipid FA composition of red blood cells and in eliminating deficiencies of physiologically important ω-3 and ω-6 PUFAs in the blood cells. CONCLUSION: The findings suggest that FAs and their metabolites play an important role in the pathogenesis of MS and that dietary ω-3 PUFA should be incorporated into a package of preventive and therapeutic measures for MS.

[The influence of sinusoidal modulated currents on the fatty acid composition of plasma and blood erythrocytes in the patients presenting with chronic cholecystitis]. / Vliyanie sinusoidal'nykh modulirovannykh tokov na sostav zhirnykh kislot plazmy i eritrotsitov krovi u patsientov s khronicheskim kholetsistitom.

The objective of the present study was to evaluate the effectiveness of the treatment with sinusoidal modulated currents on lipid metabolism in the patients presenting with chronic cholecystitis in the state of remission. PATIENTS AND METHODS: The study included 25 patients with chronic non-calculosis cholecystitis in phase of remission and 20 healthy subjects (controls). We studied the serum lipid spectrum as well as the fatty acid composition of plasma and blood erythrocytes before and after therapy with sinusoidal modulated currents applied to the right-sided hypochondrium region. RESULTS AND DISCUSSION: The treatment of the patients with chronic cholecystitis in remission with the use of sinusoidal modulated currents produced moderate lipid-modulatory and membranotropic effects mediated through the activation of the processes of lipid metabolism that may result in the depletion of the pool of essential polyunsaturated fatty acids. CONCLUSION: The results of this study give evidence that it is advisable to treat the patients presenting with chronic cholecystitis by sinusoidal modulated currents in the combination with the oral intake of exogenous polyunsaturated fatty acids.

PT/Y Mice Are Sensitive to the Inhibitory Effect of o-Aminoazotoluene on Glucocorticoid Induction of Tyrosine Aminotransferase and Its Hepatocarcinogenic Effect.

PT/Y mice used for studies of the effects of mutagens are characterized by the absence of spontaneous tumors of the liver, but often develop these tumors in response to chronic oaminoazotoluene treatment. The level of glucocorticoid induction of adaptive hepatic enzyme tyrosine aminotransferase decreases by more than 70% 24 h after acute injection of o-aminoazotoluene to these animals. These mice can serve as a model for studies of the relationship between the effect of carcinogens on the regulation of activity of adaptive hepatic enzymes and their capacity to induce the development of liver tumors.

Hepatoprotective properties of betulonic acid amide and heptral in toxic liver injury induced by carbon tetrachloride in combination with ethanol.

Toxic liver injury with the development of fibrosis and cirrhosis was modeled in Wistar rats by intragastric administration of 0.1 ml/kg CCl4 in combination with 5% ethanol with glucose 3 times a week for 6 weeks. The animals were treated with betulonic acid amide (50 mg/kg in Tween aqueous solution) and heptral (6 mg/kg) as hepatoprotective compounds. It was found that betulonic acid amide stimulated the regenerative response in hepatocytes under conditions of combined toxic exposure and promoted recovery of their qualitative and quantitative characteristics, which was accompanied by a significant decrease in the severity of liver fibrosis and the absence of cirrhotic transformation of the liver.

[Role of opisthorchis felineus on induction of bile duct cancer].

Opisthorchis felineus (Trematoda) is widespread in the Russian Federation, especially in Siberia, and other countries of Europe. Infestation of endemic area population with O. felineus reaches 80%. On animal models of the infection of closely related Opisthorchis viverrini combined with the nitrosamines' intake it has been shown that the parasite induces cholangiocarcinoma. However carcinogenic potential of O. felineus is still poorly studied. The present study is aimed to investigate the role of O. felineus in cholangiocarcinoma carcinogenesis in hamster treated additionally by dimethylnitrosamine (DMN). Golden hamsters were divided into 4 groups (15 specimens in the control group and 20 for other groups): (I) untreated control, (II) 12.5 ppm DMN solution intake, (III) infected with 50 metacercariae of O. felineus and (IV) infected with 50 metacercariae of O. felineus and 12.5 ppm DMN solution intake. According to the histological data, in the. O. felineus-infested group significant hyperplastic and dysplastic biliary changes were found considered as a precancerogenic state. Such pathological changes of bile ducts were more severe in group treated with both factors, with cholangiocarcinoma being found out at 18th week in all the animals of this group. These results demonstrate that O. felineus could play promoting role in two-step model in cholangiocarcinoma carcinogenesis and may be used to define the O.felineus group in the International Agency for Research on Cancer classification of agents, mixtures and exposures (IARC categories).