Hidematsu Hirai

Lectin affinity electrophoresis of α-fetoprotein: Increased specificity and sensitivity as a marker of hepatocellular carcinoma

alpha-Fetoprotein (AFP) is widely used as a marker of hepatocellular carcinoma (HCC) for assisting diagnosis and also for screening purposes, even though its sensitivity has been decreased slightly as a result of the earlier detection of HCC by ultrasonography. Using lectin-dependent fractionation of AFP, the diagnostic sensitivity as well as the specificity of AFP can be increased compared with measurement of total AFP. Furthermore, lectin-reactive forms of AFP, AFP-L3 and AFP-P4, have been shown to serve as preclinical markers of HCC. Accordingly, AFP is still the most reliable marker of HCC in screening and monitoring high-risk patients.

Immunochemical studies on catalase: II. An anticatalase reacting component in normal, hypocatalasic, and acatalasic human erythrocytes

Abstract Quantitative precipitin studies coupled with immunochemical techniques have identified in normal human erythrocytes a minor component of catalase which, though reacting with rabbit antihuman catalase serum, lacks enzyme activity. Hemolyzates from presumed carriers (heterozygotes) of the gene for acatalasia also show the minor component, though the quantity of the active enzyme itself is reduced. Preparations from acatalasic (homozygotic) individuals contain only the minor inactive component. Purification by Sephadex gel filtration shows the minor component to have a molecular weight about one sixth of the fully constituted active enzyme. There is no Soret absorption. The authors postulate the minor component to be a subunit or precursor of catalase, or both. Based on these findings, a possible genetic interpretation of the defect in human hereditary acatalasia is offered.

Datura stramonium Agglutinin-Reactive α-Fetoprotein Isoforms in Hepatocellular Carcinoma and Other Tumors

By means of Datura stramonium agglutinin (DSA) affinity electrophoresis, human alpha-fetoprotein (AFP) was resolved into five bands, AFP-D1, D2, D3, D4 and D5, in order of decreasing mobility. AFP-D1, which had no affinity for DSA, comprised more than 84% of the intensity of total AFP bands. The percentage of AFP-D2 increased marginally in hepatitis and liver cirrhosis with or without hepatocellular carcinoma. AFP-D3 increased characteristically in hepatocellular carcinoma and AFP-D4, which had the highest affinity for DSA, increased up to 12% in other tumors, mostly of gastrointestinal origin. AFP-D5 showed no consistent changes among the benign and malignant diseases. The assay of AFP-D3 and D4 proved useful as a highly specific marker of hepatocellular carcinoma and other tumors, respectively.

Lectin Reactivity of Alpha-Fetoprotein in a Case of Renal Cell Carcinoma

The increased serum level of alpha-fetoprotein (AFP) in a case of renal cell carcinoma, a rare condition of AFP production by mesoderm-derived cells, was evaluated for its lectin reactivity by affinity electrophoresis, followed by the antibody-affinity transfer to nitrocellulose membranes for visualization of separated AFP bands. The AFP of this case was characterized by relative increases of concanavalin A-nonreactive AFP-C1 (60.4%), erythroagglutinating phytohemagglutinin-reactive AFP-P4 (37.8%) and AFP-P5 (46.3%) and Allomyrina dichotoma lectin-nonreactive AFP-A1s (66.7%), and by the total absence of lentil lectin-reactive components, AFP-L2 and AFP-L3. Thus, the lectin-reactive pattern of AFP markedly deviated not only from that of cord serum, but also from those of other malignancies and of fetal kidney cells in culture.

Increased serum levels of monosialo-alpha-fetoprotein in hepatocellular carcinoma and other malignancies.

Serum alpha-fetoprotein (AFP) from cord blood and from patients with hepatitis, cirrhosis, hepatocellular carcinoma, gastrointestinal tumors and yolk sac tumor was analyzed by extended agarose gel electrophoresis coupled with our sensitive detection method of antibody-affinity blotting. AFP was separated into AFP-A, AFP-B and AFP-C from the anode to the cathode, corresponding to disialo-, monosialo- and asialo-AFP, respectively, as revealed by the results of neuraminidase digestion of serum AFP. AFP-Af, which migrated ahead of AFP-A as band or leading smear and varied widely in intensity, was eliminated in calculating the proportions of other band intensities. Disialo-AFP was the major component and monosialo-AFP the minor one in benign conditions, the latter being 4.2 +/- 6.0% in chronic hepatitis and 9.0 +/- 8.9% in cirrhosis. Monosialo-AFP in hepatocellular carcinoma was increased significantly, the proportion being 29.9 +/- 11.2%. AFP in other malignancies was further characterized by the appearance of asialo-AFP.

The effect of estriol on the production of alpha-fetoprotein by the liver in adult mice

A single intraperitoneal injection with a 10 mg estriol (E3) in aqueous suspension induced a large and prolonged elevation of serum alpha-fetoprotein (AFP) in adult mice. E3 also raised the mitotic activity of hepatocytes in the absence of liver injury. Although both the AFP concentration and hepatocyte proliferation reached the peak on day 5 after E3 administration, a high level (about 12500 ng/ml) of serum AFP persisted for a long period after hepatocyte proliferation declined. Five mg E3 showed a remarkable threshold effect on AFP elevation and 3 mg E3 on hepatocyte proliferation. Immunohistochemical studies indicated AFP production by hepatocytes in adult mice after the E3 administration.