Background: Currently, colorectal cancer (CRC) ranks as the third most common cancer and the second leading cause of cancer-related mortality worldwide. CRC frequently metastasizes to the liver (50%), lungs (10–15%), peritoneum (4%), bones (10.7%–23.7%), brain (0.3%–6%), and spinal cord. Approximately 35% of CRC cases are diagnosed before distant metastasis, 36% upon lymph node involvement, and 23% after distant organ metastasis. Although several studies have established primary tumor models in mice in our country, there are limited studies on experimental lung metastasis models, prompting the need for this research. Aim: To establish and evaluate a lung metastasis model of colorectal cancer in C57BL/6J mice using the MC38 cell line. Materials and Methods: This study was conducted at the Institute of Biomedical Sciences, Mongolian National Uni versity of Medical Sciences. Approval was obtained from the Ethics Review Board of the Mongolian National Univer sity of Medical Sciences (2023/3-09) and all laboratory safety regulations and protocols were strictly followed. Male C57BL/6J mice bred at the Experimental Animal Center of Mongolian National University of Medical Sciences were used. MC38 murine colorectal carcinoma cells were cultured and injected intravenously (via the tail vein) at a concen tration of 0.25×10⁶ cells per mouse (n=12) to induce lung metastasis. Histological analysis was subsequently performed. Results: Histological examination revealed significant alterations in lung tissue architecture, characterized by areas of dense infiltration by pleomorphic, hyperchromatic cells, disrupting the normal alveolar structure. No histological abnor malities were observed in other organs. Conclusion Intravenous injection of MC38 colorectal adenocarcinoma cells into the tail vein of C57BL/6J mice success fully induced lung metastases, characterized by hyperchromatic, pleomorphic cell infiltrates forming glandular structures within the lung parenchyma.

Background: Cardiac surgery with cardiopulmonary bypass is grown rapidly in last years. The application of cardiopulmonary bypass using a heart-lung machine to perform open heart surgery is known to be associated with numerous pathophysiologic changes including injury of cellular components as erythrocyte, platelets, coagulopathy, and fibrinolysis. Objectives: Our study objective is to study on relation of open heart surgery phases and blood coagulation parameters. Materials and Methods: Blood samples from 49 patients (28 females and 21 males, aged 18- 63 years) who underwent open heart surgery with cardiopulnonary bypass (CPB) were collected before and at several time points during, after surgery and analyzed for coagulation parameters at Shastin Third Central Hospital. Results: To compare long continued cardiopulmonary bypass (over 1 h) surgery with less 1 h groups there prothrombin time was found 18.8±5.9 sec, international normalized ratio (INR) 2.09±0.9 sec prolonged (p<0.001) in 7 days after surgery. All coagulation parameters were decreased significantly (p<0.001) in during extracorporeal circulation and after 1 h declamping than preoperative level and reached near normal value in 48 h after surgery. Our results have referred to platelet counts reduction to about 53% in during surgery, 46.8% in 48 h after surgery of the preoperative level 237.4±57.1 with final return to normal levels 228.9±78.6 within 7 days. Conclusions
1. The cardiopulmonary bypass time and patient age in relation to open heart surgery type there were significant difference (p <0.01).
2. The coagulation parameters have revealed significant changes (p <0.01) in relation cardiopulmonary bypass time.
3. All coagulation parameters were decreased significantly (p<0.001) in during extracorporeal circulation and after 1 h decamping than preoperative level and reached near normal value in 48 h after surgery.
4. There was direct and less correlation between platelet level and CPB time (r=0.37, p<0.001).