Monoclonal antibody A7-superparamagnetic iron oxide as contrast agent of MR imaging of rectal carcinoma

Superparamagnetic iron oxide (SPIO)-based colloid has been used clinically as a tissue-specific magnetic resonance contrast agent. We coupled monoclonal antibody A7 (Mab A7), which reacts specifically with human colorectal carcinoma, to Ferumoxides (SPIO) and examined the accumulation of this conjugate in xenografted tumours in nude mice. We examined in vitro immunoreactivity of Mab A7 coupled to Ferumoxides and its in vivo distribution in nude mice with human colorectal carcinoma. Magnetic resonance imaging of tumour-bearing nude mice was performed 72 h after injection of A7-Ferumoxides. A7-Ferumoxides retained binding activities that were nearly identical to intact Mab A7. More of the radiolabelled A7-Ferumoxides accumulated in the tumour than normal mouse IgG-Ferumoxides from 12 h onwards after injection (P<0.05). Both A7-Ferumoxides and normal mouse IgG-Ferumoxides disappeared from blood linearly over time. The accumulation levels in normal tissue decreased linearly over time but were lower than levels in tumours from 6 h. In magnetic resonance T2-weighted imaging of the tumour-bearing nude mice, signal intensity was reduced at the margin of the tumour by injection of A7-Ferumoxides. Mab A7 coupled to Ferumoxides is potentially suitable as a magnetic resonance contrast agent for detecting local recurrence of rectal carcinoma

Three cases of small hepatocellular carcinoma presenting as obstructive jaundice

BackgroundDespite improved diagnostic tools, it is often difficult to make a correct diagnosis of small hepatocellular carcinoma (HCC) in patients with obstructive jaundice.Case outlinesThree cases of small HCC (<2 cm diameter) presenting as obstructive jaundice are reported. All tumours were initially diagnosed as hilar cholangiocarcinoma based on ultrasonography, computed tomography, cholangiography and angiography. Because of insufficient hepatic function, none of the patients underwent hepatic resection. One patient died 8­months after first admission to our hospital, another died of disseminated intravascular coagulation 1 month after admission, and the third was treated with hepatic arterial infusion chemotherapy and survived >36 months.ConclusionIt is important to consider HCC in the diagnosis of obstructive jaundice in patients who are predisposed to HCC because of liver cirrhosis and/or chronic viral hepatitis, and have elevated serum alpha‐fetoprotein