As the immersion comes to an end, I spent most of this week preparing and running experiments to wrap up my project. I ran another flow cytometry experiment to check for tissue factor (TF) expressions in prostate cancer cell line. Expanding on the list of cell line, I tested C4-2 (metastatic prostate cancer LNCap cells planted into castrated mice host and removed after week 4 twice), RWPE (benign prostate epithelial cells) and MDA-MB-231 cells (metastatic breast cancer cell from Ithaca to be used as a control) in addition to PC3 cells (metastatic prostate cancer cells) which I tested last time. Unfortunately, C4-2 was negative for TF expression, while PC3 was once again weakly positive. RWPE cells were positive, however, much to my disbelief. This is most likely the fact that they are epithelial cells, not benign non-metastatic cancer cells. TF can be expressed in subendothelial cells to form blood clots in the case of blood vessel damage. I had thought that RWPE cells were non-metastatic cancer cells, so they can give some differences with PC3 cells as TF is typically only expressed on metastatic cancer cells.
In a second experiment, I spiked PC3 cells into blood from a non-cancerous person to see if TF can be used to identified the cancer cells. The PC3 cells were pre-stained with a live dye before spiking to distinguish it from other cells from the blood donor. The blood was processed with Ficoll and the buffy layer with the PC3 cells and mononuclear (PBMC) cells were separated and further stained with TF antibodies for flow cytometry. Compared to blood controls, the spiked controls has two populations - PBMC cells and PC3 cells. However, the TF expression in the PC3 cell population was not that high. Compared to mouse IgG antibody control, the number of events positive for TF was increased from 196 to 210. The small difference could be because most of the cells detected were PBMC cells. If I had increased the number of events further, the difference may be more significant. However, given how weak TF expression is in the cell line, TF may not be the best marker for prostate cancer cells.
In terms of clinic, I went to PICU twice this week to shadow each of the two teams. The residents, fellows and attending were all very friendly and have taken the chance and opportunity to explain many of the cases and details to me. Some of the people were there post-op, others were preparing for operations. There was a cardio and a neuro team. In the cardio team, most of the babies have congenital cardiac defects in which the heart did not develop properly, and a surgery is necessary to fix it. One of the baby I saw in delivery had an aortic arch that stopped at the end, so then the surgeon must connect the arch back to the heart. In the neuro team, some of the babies have tumor in neural tissue. Other babies have recurrent tumor in the brain, and little can be done to treat the babies.
I always spent a few hours in radiation oncology to see what radiation therapy is and the procedure used to treat patients. In general, a consultation session is needed in which a CAT scan is taken of the region to be treated of the patient. The radiation oncologist then planned the treatment (i.e. the dose, type of radiation, where to shoot) with dosimetrist and physicist to come up with a plan. Then, the patient goes through the treatment daily from Monday to Friday for weeks. This treatment is usually used for local tumors, but is also used to palliate bone pain and to prevent new bone growth after hip implant.
I only went to see one surgery this week. I was originally in another surgery, but then I heard about an emergency surgery that required bypass instantly across the hall. The circulating nurse pulled me aside and told me to go to that room and it would be definitely worthwhile. So I went into the room which was in a state of chaos with 30 surgeons, anthesiologist, nurses, students, residents and fellows running around. A surgeon was performing heart compression, while surgeons are attempting to perform a bypass through the femoral vein, the anesthesiologists working their magic and the rest of the room prepping him for surgery. Before further describing the procedure, it is probably better to explain the conditions. All in all, I don't exactly know what happen was most of the nurses and surgeons don't either and I didn't want to get into the way for a good chunk of the surgery. What happened was that the patient had a Nissen procedure to connect the stomach to the esophagus to prevent acid reflux. The procedure was successful and the patient was wheeled back to his room when suddenly he crashed. They suspect that he had a embolus in the femoral vein from lying too long on the table, and the change in pressure in the abdomen caused it to dislodge and caused his heart to stop functioning. There was also a mention of arrhythmia which may be caused the conditions. Back to the surgery - they then opened the heart, and also accessed the femoral vein from the other leg to put a balloon in to regulate the blood flow. Further operation was performed on the heart (which I can't see). After awhile, they tried to remove bypass, but cannot after multiple tries as the blood pressure was really low (40s/30s). In the end, they transferred him to a VAD (mobile bypass unit) and he was to be kept on bypass and wheeled back to ICU in that manner. Brain damage may also be a problem for the patient as he may have accumulation of CO2 in his brain.
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