[Elevation of serum apo E-rich HDL concentration in a patient with cholestatic liver disease]

A remarkable elevation of serum HDL cholesterol concentration (165mg/dl) was found in a 42-year-old Japanese male with chronic pancreatitis who had been cholestatic for several years. An abnormal slow alpha-migrating lipoprotein, larger in particle size and more enriched with cholesteryl ester and apo E than normal HDL, was found in the patient's plasma. Quantitative determination of apo E-rich HDL revealed a striking increase of this lipoprotein in plasma. After choledocho-jejunostomy, a prompt and remarkable decrease of plasma apo E-rich HDL was observed, indicating a direct contribution of cholestasis to the accumulation of apo E-rich HDL in plasma in this patient.

[A case of hyperalphalipoproteinemia with complete deficiency of cholesteryl ester transfer activity]

A 68-year-old male patient with benign hypertension shows high levels of high density lipoprotein cholesterol (HDL-C) of 171 mg/dl. The serum total cholesterol was 240 mg/dl. An abnormal slow alpha band and polydisperse low density lipoprotein (LDL) bands were detected by agarose gel and polyacrylamide gel electrophoresis. The slow alpha band was considered as an apo E-rich HDL. A peak of large HDL particle and a peak of abnormal high-molecular-LDL particle were observed in the patient's serum by gel permeation high performance liquid chromatography. Cholesteryl ester transfer activity (CETA) of the patient's serum was completely deficient (0.0%/10 microliters/18 hr). From these results, it is strongly suggested that patient's hyper-HDL-cholesterolemia caused by a complete deficiency of CETA.

Separation and characterization of sialic acid-containing salivary-type amylase from patients' sera with immunoglobulin A-type myeloma

Isoamylases, with an abnormal anodic migration, were detected by an electrophoretic technique in the sera from two patients with immunoglobulin A-type myeloma. The abnormal isoamylase bands migrate towards the anode faster than the salivary isoamylase (S2) band and were stained more strongly than the S2 sub-band. The abnormal isoamylase could be separated from patients' sera by using size-exclusion high-performance liquid chromatography. The serum abnormal isoamylases were showed to be sialic acid residues containing amylase, after the study of treatment with neuraminidase (EC 3.2.1.18), and to be salivary-type amylase, after the study of reaction with human salivary monoclonal antibody. The abnormal bands were not detected in the saliva from one patient. The two patients had no detectable malignancies except myeloma. These findings strongly suggest that the sialic acid-containing salivary-type amylases were produced ectopically from myeloma cells. In this regard the ectopic amylase production by myeloma cells is discussed.

Incidence and properties of aspartate aminotransferase-immunoglobulin complexes in patients with a high serum aspartate to alanine aminotransferase ratio

Sera of 260 patients with high serum aspartate aminotransferase (L-aspartate: 2-oxoglutarate aminotransferase, EC 2.6.1.1; AST)/alanine aminotransferase (L-alanine: 2-oxoglutarate aminotransferase, EC 2.6.1.2; ALT) ratio (greater than 2.0) and high serum AST (greater than 45 IU/1) were selected and tested for the presence of immunoglobulin complexed-AST, by using immunoprecipitation reaction and counterimmunoelectrophoresis. The macromolecular AST was confirmed by size-exclusion high-performance liquid chromatography (HPLC). 34 patients out of 260 were found to have AST-immunoglobulin complexes (13.1%). The classes of AST-linked immunoglobulins were identified to be alpha in 28 cases (82.4%, P less than 0.01), mixed type of alpha and gamma in 5 cases (14.7%) gamma in one case (2.9%). Positive frequency was the highest in liver malignancies, either primary (9/26, 34.6%) or metastatic (7/17, 42.2%), followed by other malignancies (6/55, 10.9%) and chronic liver diseases (4/22, 18.2%). Thus, it can be strongly suggested that the immunoglobulin A complexed-AST is frequently found in association with liver malignancies.

Characterization of amylase linked immunoglobulin G to distinguish human salivary and pancreatic isoamylases

An immunoglobulin G of the kappa type linked to salivary amylase was identified in the serum of a patient with colon cancer and persistent hyperamylasemia. The binding site on the immunoglobulin in the complex is located in F(ab')2 portion. The purified IgG recombined only with purified human salivary amylase, and could be used to separate human isoamylases.

Mitochondrial aspartate aminotransferase linked to immunoglobulin G of the kappa-lambda type: report of a case

Macromolecular aspartate aminotransferase (L-aspartate: 2-oxoglutarate aminotransferase EC 2.6.1.1, AST) was found in the serum of a patient with benign hypertension. The serum total AST and mitochondrial AST (mAST) activities were proportionately higher. The abnormal AST was found to be a macromolecular complex composed of mAST and immunoglobulin G of the kappa-lambda type. The dissociated IgG from the complex was shown to combine with human and rat mAST, but not with cytosolic AST of both species. Molecular mass of the macromolecular AST was estimated to be 360,000 Da. These results indicate that the complex may consist of one IgG molecule associated with two mAST molecules. By the method of papain digestion the binding site of immunoglobulin in the complex appeared to be located in the Fab portion of the IgG molecule. This finding strongly suggests that the AST-immunoglobulin complex is a specific antigen-antibody complex.

[Macroamylasemia, report of two cases]

Serum amylase isozyme was determined in 2 cases with normal urinary amylase but persistantly high serum amylase. Both cases showed dominant S-type amylase associated with tailing findings that was characteristic of macroamylasemia. Moreover, using the immunofixation method, the serum amylase was found to be bound with IgG (K) in case 1 and with IgA (L) in case 2.