Metastatic Choriocarcinoma with Negative Pelvic Examination

Apeculiar case of choriocarcinoma of the left parietal lobe of the brain with intracerebral hemorrhge is presented. Pelvic findings by physical and radiological examination were negative postoperatively, a thorough radiological study that included chest PA, chest CT, abdominal CT, pelvic CT and pelvic ultrasonography were performed for the detection of its primary focus. The level of urine and serum beta-HCG was above 100.000mlU and of CSF was 1,600mlU. This case is thus metastatic in nature, yet the primay focus of the tumor could not be demonstrated.

Antioxidant Action of Transthyretin in Human Cerebrospinal Fluid

Protective effect of human cerebrospinal fluid antioxidants against enzyme inactivation caused by metal-catalyzed oxidation systems were investigated. When purified glutamine synthetase(GS) was incubated with human cerebrospinal fluid(CSF), the enzyme was progressively inactivated. Catalase and EDTA could inhibit the enzyme inactivation by 50-80%. Small-molecular(Mr-10,000) fraction did not. The GS inactivation by the small-molecular fraction was also markedly inhibited by catalase and EDTA. These results suggested that metal-catalyzed oxidation is involved in the GS inactivation by the small-molecular fraction of CSF. Dithiothreitol(DTT)was shown to inhibit almost completely the oxidative inactivation of GS by CSF. However, DTT inhibited only partially the oxidative inactivation of GS caused by small-molecular fraction of CSF. When large-molecular fraction of CSF was separated by anion-exchange HPLC chromatography, there was a peak of antioxidant activity inhibiting the small-molecular fraction-induced GS inactivation in the presence of DTT. The antioxidant activity was neutralized by monoclonal antibodies to transthyretin. Purified transthyretin was found to efficiently inhibit ascorbate/Cu2+-induced GS inactivation in the presence of DTT. Uric acid and glucose did not shoe any protective effect on the GS inactivation in the same condition. The above results suggest that metal-catalyzed oxidation occurs normally in human CSF, and the transthyretin may play an important role as a CSF antioxidant in protecting proteins from metal-catalyzed oxidation.