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Biomedical subjects

H Itakura

Publications and source records attributed to H Itakura.

At least 163 records · Page 9Linked to original sources
PubMed1983

Serum lipoprotein measurement--liquid chromatography and sequential floatation (ultracentrifugation) compared.

An HPLC method [J. Biochem. (Tokyo) 91:1381, 1982] was used for evaluating serum lipoproteins, with on-line monitoring of either cholesterol or phospholipids. Five well-distinguished lipoprotein fractions were observed, based on their particle sizes. Serum of 15 normal persons, 12 subjects with various types of hyperlipidemia, 20 patients with various liver diseases, and two cases of familial LCAT deficiency were examined and the results compared with those by a sequential ultracentrifugal floatation technique. In the normal group, the amounts of fractions 2, 3, and 4 by the HPLC method correlated well with concentrations of the LDL, HDL2, and HDL3 fractions as measured by the ultracentrifugal method, respectively. In the hyperlipidemic group, similar good correlations were observed between fractions 1, 2, 3, 4 and chylomicrons + VLDL, LDL, HDL2, and HDL3 fractions, respectively. For those with liver diseases or LCAT deficiency, the corresponding fractions correlated less well, and characteristically the elution profile of lipoproteins in these groups showed heterogeneity of particle size within each lipoprotein density class, especially in LDL and HDL2.

Cholesterol↗
PubMed1983

Changes in aminolevulinate synthase and aminolevulinate dehydratase activity in cirrhotic liver.

Delta-Aminolevulinate synthase and delta-aminolevulinate dehydratase activities were determined in liver biopsy specimens obtained from 12 patients with hepatic cirrhosis. Delta-Aminolevulinate synthase activity was determined by the incorporation of [1,4-14C]succinyl coenzyme A into delta-aminolevulinate. The mean activity of delta-aminolevulinate synthase was significantly higher in cirrhotic liver specimens (mean +/- SE, 193.7 +/- 34.5 picomoles delta-aminolevulinate per milligram protein per 30 minutes) than in controls with minimal histologic changes (32.7 +/- 13.6, p less than 0.01). Furthermore, the mean activity of delta-aminolevulinate synthase was higher in micronodular cirrhosis (281.6 +/- 58.8) than in the other types of cirrhosis (131.0 +/- 23.1, p less than 0.05). Levels of indocyanine green retention at 15 min correlated with the activity of hepatic delta-aminolevulinate synthase (p less than 0.05). The mean activity of delta-aminolevulinate dehydratase, in contrast, was significantly lower in cirrhotic liver specimens (9.4 +/- 1.3 nanomoles porphobilinogen per milligram protein per hour) than in controls (22.0 +/- 2.6, p less than 0.05). These results suggest that the extent of liver injury or the degree of portosystemic shunting, or both, influence the rate of hepatic heme biosynthesis.

5-Aminolevulinate Synthetase↗
PubMed1982

Plasma apolipoprotein E levels in hypertriglyceridemia.

A specific, precise and sensitive double-antibody radioimmunoassay for the measurement of human apolipoprotein E (apo E) was developed. Antibody specific to apo E was raised in a rabbit. This antibody did not crossreact with plasma low density lipoproteins (d = 1.030-1.063) and apo-proteins such as pao CII, CIII, AI and AII. Mean plasma level with SD of apo E in 29 normalipidemic subjects was 9.5 +/- 1.8 mg/100 ml. Plasma apo E concentrations in 25 hypertriglyceridemic patients with plasma triglyceride concentrations ranging from 169 to 1190/mg/100 ml correlated positively with plasma triglyceride concentrations (r = 0.84, p less than 0.001). Among subjects with hypertriglyceridemia, there was a negative correlation between the apo E per mg triglyceride ratio and plasma triglyceride concentrations (r = 0.49, p less than 0.02). Plasma apo E levels did not show any correlation with plasma cholesterol concentrations. These results indicate that plasma apo E is closely associated with plasma triglyceride levels, which suggests a possible connection of this apoprotein with the metabolism of plasma triglyceride.

Adult↗
PubMed1982

Primary liver carcinoma and liver cirrhosis in atomic bomb survivors, Hiroshima and Nagasaki, 1961-75, with special reference to hepatitis B surface antigen.

During 1961-75, 128 cases of primary liver carcinoma (PLC) in the Radiation Effects Research Foundation life-span study extended sample and 301 cases of liver cirrhosis in the pathology study sample were observed. The presence of hepatitis B surface antigen (HBsAg) was assessed in all of the cases with the use of orcein and aldehyde fuchsin stains and was confirmed by the immunofluorescence technique. The incidence of PLC was two times higher in Nagasaki than in Hiroshima, which was statistically significant, but little difference was noted in the prevalence of cirrhosis in the two cities. Findings that might possibly explain the higher PLC incidence in Nagasaki were 1) the 2.3 times higher presence in Nagasaki than in Hiroshima of HBsAg in the livers of subjects without liver disease and 2) the two times higher prevalence in Nagasaki than in Hiroshima of cirrhosis with PLC. We believe that the higher incidence of PLC in Nagasaki is attributable to hepatitis B virus infection, although other factors (e.g., immunologic competence affected by radiation) cannot be excluded. In both cities, a suggestive relationship of radiation dose to cirrhosis prevalence, but not to PCL prevalence, was noted. To clarify possible radiation effects on cirrhosis prevalence, further follow-up of the populations of these two cities is necessary.

Adult↗
PubMed1982

Familial plasma lecithin: cholesterol acyltransferase deficiency. A new family with partial LCAT activity.

A 43-year-old woman and her 47-year-old brother were studied because of corneal opacity. They showed a marked decrease in plasma high density lipoproteins (HDL) and a decrease in the ester ratio of plasma total cholesterol. Discoidal particles were found in the HDL2 fraction (d 1.063-1.125). A marked heterogeneity of low density lipoproteins was disclosed in both patients by electron microscopy. Apoprotein analysis revealed an increase in apo E and a decrease in apo A-I and A-II in both patients. These abnormalities were similar to the data reported in other cases with hereditary lecithin : cholesterol acyltransferase (LCAT) deficiency. However, several interesting dissimilarities have been disclosed as compared with the previously reported cases. Neither patient had proteinuria, and their kidney functions were within the normal limits. The ester ratios of plasma cholesterol of both patients were the highest among the cases reported thus far. Their plasma LCAT activities were 14.4 and 15% of the normal mean values determined by Glomset-Wright's common-substrate method. The enzyme activities determined by Stokke-Norum's self-substrate method were 40.2 and 29% respectively. These results may indicate that this inherited disorder is not characterized by absence of plasma LCAT or presence of inhibitory factors in plasma, but by the presence of partially inactive LCAT in patients' plasma.

Adolescent↗
PubMed1981

Ascites chylomicron: a poor substrate for hepatic triglyceride lipase.

A patient with nephrotic syndrome and morbus Kimura (eosinophilic granuloma) showed chylous ascites. Ascites chylomicrons were analyzed and used to study the substrate specificity of lipoprotein lipase and hepatic triglyceride lipase. Ascites triglyceride and cholesterol concentrations were 191 and 12 mg/dl, respectively. Both apo CII and apo CIII content in ascites were approximately one-third of those of plasma from normal subjects. Ascites chylomicrons were incubated with either lipoprotein lipase or hepatic triglyceride lipase, which were prepared from postheparin plasma using heparin-Sepharose affinity chromatography. Lipoprotein lipase hydrolyzed ascites chylomicrons, while hepatic triglyceride lipase did not. These results suggest different functions of these two lipases in chylomicron catabolism.

Ascites↗
PubMed1981

Accumulation of intermediate density lipoprotein in plasma after intravenous administration of hepatic triglyceride lipase antibody in rats.

In an attempt to define the role of hepatic triglyceride lipase in plasma lipoprotein metabolism, in vivo experiments using an antibody specifically prepared against this enzyme were conducted in rats. The antibody gamma globulins were injected into rats three times during a 40 min period. Control rats received non-immune rabbit gamma globulins prepared in the same way as the immune gamma globulins. After treatment, blood was taken and the plasma was separated. Plasma lipoproteins were fractionated by ultracentrifugation into VLDL, IDL, LDL and HDL. Treatment of recipient rats with the antibody significantly increased cholesterol, phospholipid and protein concentrations in the IDL fraction. These concentrations were also elevated in the LDL fraction. However, we speculate that this increase represents the accumulation of small remnants rather than bona fide LDL. VLDL compositions in antibody-treated rats did not differ from those in control animals. In HDL, only the phospholipid level was elevated in antibody-treated rats. The data of the present study indicate that hepatic triglyceride lipase mediates the catabolism of remnant lipoproteins by the liver.

Animals↗
PubMed1980

Isolation and partial characterization of two immunologically similar vitamin D-binding proteins in rat serum.

Two immunologically similar, probably identical, binding proteins for vitamin D and its metabolites (DBP1 and DBP2) were isolated separately from rat serum after approximately 180-fold purification by novel procedures using Blue Sepharose CL-6B chromatography. The freshly purified DBP1 and DBP2 each showed a single band of protein on polyacrylamide gel electrophoresis, and had alpha-mobility, although DBP1 moved slightly faster than DBP2. DBP1 and DBP2 had the same molecular weight, which was estimated as approximately 54,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The isoelectric points of DBP1 and DBP2 were estimated as 4.9 and 5.0, respectively, from the results of isoelectric focusing experiments. DBP1 and DBP2 both appeared to have one binding site for 25-hydroxyvitamin D3 per molecule of protein, with apparently similar association constants at 4 degrees C of 5--7 x 10(9) M-1. The amino acid compositions of DBP1 and DBP2 were also determined and compared. A monospecific antiserum against rat DBP2 was prepared in a rabbit and was used for immunological studies of rat DBP. On double immunodiffusion, anti-DBP2 antiserum produced precipitin lines of complete reaction-of-identity against the purified DBP1, the purified DBP2, and rat whole serum. There was no immunological cross-reactivity between rat DBP and sera from man, dog, and rabbit, but mouse serum showed a pattern of partial identity with rat DBP. When rat serum samples were analyzed by immunoelectrophoresis using anti-DBP antiserum, three patterns of precipitin line were observed: a pattern showing the existence of only DBP1, designated as DBP 1-1; a pattern showing the existence of only DBP2, designated as DBP 2-2; and a pattern showing the existence of both DBP1 and DBP2, designated as DBP 2-1. Using single radial immunodiffusion assay for rat serum DBP, the mean (+/- S.D.) serum DBP concentrations were found to be 461 +/- 59 microgram/ml in adult male rats and 328 +/- 16 microgram/ml in adult female rats, and the difference was significant (p < 0.001). In molar terms, DBPs are present in normal rat serum in large excess relative to vitamin D and its metabolites, and most of the serum DBP, therefore, circulates as apo-DBP, not containing a bound molecule of vitamin D or of its metabolites. The immunoprecipitation studies of DBP in rat serum showed that DBPs were common main transport proteins for naturally occurring vitamin D and its metabolites, and that DBP played some, but not a principal, role in the transport of synthetic 1 alpha-hydroxyvitamin D3.

Amino Acids↗
PubMed1980

Serum 25-hydroxyvitamin D and vitamin D-binding protein levels and mineral metabolism after partial and total gastrectomy.

The effects of gastrectomy, especially total gastrectomy, on the serum levels of 25-hydroxyvitamin D and vitamin D-binding protein and on mineral metabolism were examined. The serum 25-hydroxy-vitamin D levels were markedly decreased in patients with total gastrectomy and Billroth II gastrectomy. Decreased levels of serum vitamin D-binding protein and serum calcium, and increased levels of serum alkaline phosphatase were observed in both patients with partial gastrectomy and patients with total gastrectomy. The results show that vitamin D deficiency could develop in high frequency patients with total gastrectomy and Billroth II gastrectomy, and that deranged mineral metabolism could develop in patients with any type of gastrectomy with or without vitamin D deficiency. The decreased levels of serum vitamin D-binding protein in postgastrectomy patients may be a sensitive reflection of the failure of hepatic protein synthesis.

Aged↗
PubMed1979

A selective deficiency of hepatic triacylglycerol lipase in guinea pigs.

The properties of postheparin plasma triacylglycerol-hydrolyzing enzymes were investigated in guinea pig and rat. In rat, lipoprotein lipase and hepatic triacylglycerol lipase were separated on a heparin-Sepharose affinity chromatography. In postheparin plasma of guinea pig, however, hepatic triacylglycerol lipase was almost completely absent, while lipoprotein lipase was present. Hepatic triacylglycerol lipase was also deficient in the liver tissue extract of guinea pig. Plasma lipoprotein compositions of high-fat fed and control guinea pigs were analyzed. One of the outstanding changes found in high-fat fed animals was the presence of chylomicronemia. One guinea pig showed gross hyperlipemia with triacylglycerol concentrations of 2715 mg/100 ml. Plasma triacylglycerol concentrations of each lipoprotein fraction of very low density, intermediate density, low density and high density lipoproteins from high-fat fed animals were almost the same as those of the corresponding lipoprotein fractions from controls. Discussion was focused on the development of chylomicronemia in relation to the defects of triacylglycerol-hydrolyzing enzyme systems in this animal.

Animals↗