Production and Evaluation of Immunoreactivity of Poly Lysine-Tagged Single Chain Fragment Variable (ScFv) Lym-1 Antibody for Direct Conjugation to Fluorescence Dye / 핵의학분자영상

PURPOSE: Small size of recombinant scFv antibody has many advantages such as rapid blood clearances and improved targeting antibodies to tumor region. On the other hand owing to small size, number of amino group is insufficient in conjugation with chelator and fluorescence labeling. This study is to introduce poly lysine tag to the C-terminal end of scFv lym-1 sequence for fluorescence chelator conjugation. MATERIALS AND METHODS: Poly lysine scFv lym-1 gene, cloned into pET-22b (+) vector, was expressed in E. coli BL21 (DE3) strain. Antibody purification was performed with Ni-NTA column and then size exclusion column chromatography. Expression and purification levels of poly lysine tagged scFv lym-1 antibody were confirmed by western blot analysis. I-124, I-125, I-131 and Tc-99m were used for radiolabeling of purified poly lysine scFv lym-1. Flow cytometry analysis of FITC conjugated poly lysine scFv lym-1 was performed for confirmation of immunoreactivity of human Burkitt`s lymphoma cells. RESULTS: Poly lysine scFv lym-1 antibody was purified through two steps and identified as molecular weight of 48 KDa. Radiolabeling yields of I-124, I-125, I-131 and Tc-99m into poly lysine scFv lym-1 were >99%, >99%, >95% and >99%, respectively. Flow cytometry analysis of poly lysine scFv and scFv lym-1 was showed similar immunoreactivity to human Burkitt`s lymphoma cells. CONCLUSION: Poly lysine tag was useful for the sufficient number of amino groups to scFv lym-1 antibody for chelator conjugation with minimizing loss of immunoreactivity.

The Usefulness of 18F-FDG PET/CT for Predicting the Response of Locally Advanced Rectal Cancer to Neoadjuvant Chemoradiation Therapy / 대한방사선종양학회지

PURPOSE: This study aimed at assessing the value of fluorine-18 fluorodeoxyglucose positron emission tomography (18F-FDG PET) for predicting the response of locally advanced rectal cancer to neoadjuvant CRT. MATERIALS AND METHODS: Between August 2006 and January 2008, we prospectively enrolled 20 patients with locally advanced rectal cancer and who were treated with neoadjuvant CRT at the Korea Institute of Radiological and Medical Sciences. The treatment consisted of radiation therapy and chemotherapy, and this was followed by curative resection 6 weeks later. All the patients underwent 18F-FDG PET/CT both before CRT and 6 weeks after completing CRT. The measurements of the FDG uptake (SUV(max)), the absolute difference (DeltaSUV(max)) and the percent SUV(max) difference (response index, RI(SUV)) between the pre- and post-CRT 18F-FDG PET/CT scans were assessed. The measurements of the metabolic volume, the absolute difference (Delta metabolic volume) and the percent metabolic volume difference (response index, RI(metabolic volume)) were also assessed. RESULTS: Of the 20 patients who underwent surgery, 11 patients (55%) were classified as responders according to Dworak's classification. The post-CRT SUV(max) was significantly lower than the pre-CRT SUV(max). However, there were no significant differences in the SUV(max) and the metabolic volume reduction between the responders and non-responders. We used a minimum SUV(max) reduction of 67% as the cut-off value for defining a response, with a sensitivity of 45.5%, a specificity of 88.9%, a positive predictive value of 77% and a negative predictive value of 53.8%. CONCLUSION: Although there were no statistically significant results in this study, other studies have revealed that 18F-FDG PET/CT has the potential to assess the tumor response to neoadjuvant CRT in patients with locally advanced rectal cancer.

Clinical Study of 55 Seizure Patients

The authors had studied 55 cases with clinical seizure who were regularly treated with appropriate anticonvulsants over 6 months. In their distribution of age, teens are most freguent and their twenties followed. Males are more affected than female in the ratio of 3 to 2. Seizure may occur at any age; but our study shows that it is commoner in the first to third decades of life, about 72% of all cases, commonest in teens. The figures for 55 cases collected by us are : generalized type, 78% ; partial type, 22% ; 60% of all cases 33 are ldiopathic group, who had no demonstrable underlying neurologic abnormality. The major part of all idiopathic cases had their attacks of seizure before 30 years of age and; those of symptomatic cases are rather late over age of 30, and their figures are; cerebrovascular disorder, 6 cases; brain tumor, 5 cases; cerebral cysticercosis, 4 cases. 51 cases of all patients had evident abnormalities on their EEG. According to both their type of seizure and EEG findings, their drug was determined and, if need be, second drug was added. Freguently used drugs were dilantin, phenobarbital & Valproic acid etc. Mean therapeutic serum levels of anticonvulsants are: dilantin, 8.3 mg/L phenobarbital, 12.4 mg/L; which levels are less than those in U. S. A. In our study, the reponse to anticonvulsants were mostly good in about 2 years.

A Case of "Flip-Flap" Pattern in Cerebral Neuclear Angiogram

The characteristics of radionuclide brain scan imaging of intracranial lesion are determined, in part, by the rate and quantity of radioactive material in the region of involvement, which is associated with alterations in the blood brain barrier. Findings, noted on the blood flow studies, often serve to direct attention to forthcoming imaging of specific pathological change on the status studies, e.g, carotid artery occlusion and cerebral infarction. We have seen that the 62 year old woman with left side hemiparesis shows typical "Flip-Flap" pattern in brain scan imaging, thought to be due to carotid artery occlusion.