The Effectiveness of Ferritin as a Contrast Agent for Cell Tracking MRI in Mouse Cancer Models

PURPOSE: We aimed to investigate the effectiveness of ferritin as a contrast agent and a potential reporter gene for tracking tumor cells or macrophages in mouse cancer models. MATERIALS AND METHODS: Adenoviral human ferritin heavy chain (Ad-hFTH) was administrated to orthotopic glioma models and subcutaneous colon cancer mouse models using U87MG and HCT116 cells, respectively. Brain MR images were acquired before and daily for up to 6 days after the intracranial injection of Ad-hFTH. In the HCT116 tumor model, MR examinations were performed before and at 6, 24, and 48 h after intratumoral injection of Ad-hFTH, as well as before and every two days after intravenous injection of ferritin-labeled macrophages. The contrast effect of ferritin in vitro was measured by MR imaging of cell pellets. MRI examinations using a 7T MR scanner comprised a T1-weighted (T1w) spin-echo sequence, T2-weighted (T2w) relaxation enhancement sequence, and T2*-weighted (T2*w) fast low angle shot sequence. RESULTS: Cell pellet imaging of Ad-hFTH in vitro showed a strong negatively enhanced contrast in T2w and T2*w images, presenting with darker signal intensity in high concentrations of Fe. T2w images of glioma and subcutaneous HCT116 tumor models showed a dark signal intensity around or within the Ad-hFTH tumor, which was distinct with time and apparent in T2*w images. After injection of ferritin-labeled macrophages, negative contrast enhancement was identified within the tumor. CONCLUSION: Ferritin could be a good candidate as an endogenous MR contrast agent and a potential reporter gene that is capable of maintaining cell labeling stability and cellular safety.

The Compliance of the Patients advised Additional Laboratory Test or Treatment in the Periodic Health Screening

BACKGROUND: Recent increase in use of the periodic health screening is due to a concern for health. But study of patient's compliance with recommended periodic health screening has not yet been conducted. This study was accomplished to clarify which aspect to be considered in order to increase patient's compliance after health screening. METHODS: This study was done from March 3 to May 15 in 1997 by Hanil health care center, Among 370 workers in a state-run corporation who received health screening tw? years ago, 170 men were advised to receive an additional laboratory test or treatment at the time. They were asked to fill out a questionnaire and were inte?iewed by doctors to evaluate their compliance. 162 of 170 patients(95.3%) were enrolled in the study, except 8 patients who did not answer the questionnaire. RESURTS: The mean age of patients was 54 years. Most of them were technicians and managers, graduated from high school or higher, and had an annual income of at least 35,000,000 won. The disease of requiring an additional test or treatment were in the order of liver disease, hypertension, gastrointestinal disease, urologic disease and abnormal urinalysis. 68 patients(42%) were compliant and 94 patients(58%) were noncompliant. For reasons of noncompliance,27 patients(28.7%) answered "because l had no symptoms", 20 patients(21.2%) answered "because I didn't think I needed the test or the treatment" and 12 patients(12.7%) answered "because I was busy". The factors influencing compliance were analyzed through chi-square or Fisher's exact test. Their compliance was highly related to the patients'insight into the necessity of the test. the existing disease, and the reporting method of the health screening results. It was not associated with the patients'feeling about their health status, the health behaviors such as smoking and drinking, occupational factors, distance from shire homes to the hospital, or the presence of a hospital near home for those who didn't live in Seoul. The independent effect of the factors influencing the compliance was evaluated by means of stratified analysis. The only independent factor associated with the compliance was the patients' insight. The compliance according to diseases was higher than average in hypertension, liver disease, diabetes mellitus and urologic disease, and lower than average in pulmonary disease, gastrointestinal disease, thyroid disease, cardiac disease, opthalmologic disease and abnormal urinalysis. CONCLUSIONS: The most influencing factor related to compliance was the patient's insight into the necessity of the further testing. We should consider a proper way to increase compliance on health screening. Direct counseling, if possible, is recommended following health screening and way to increase patient's compliance utiliging mail report as another.