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H Shimasaki

Publications and source records attributed to H Shimasaki.

At least 37 records · Page 2Linked to original sources
PubMed1995

Lipid peroxidation and ceroid accumulation in macrophages cultured with oxidized low density lipoprotein.

When mouse peritoneal macrophages were cultured with oxidized human low density lipoprotein (ox-LDL), storage of ceroid-like pigments was observed within the cells by light and fluorescent microscopy, and fluorescence spectrophotometry. The fluorescent products exhibit the characteristics of Schiff base structures, having a fluorescence maximum of 430 nm and an excitation maximum of 355 nm, which has been generally accepted with fluorescent lipid peroxidation products. Similar fluorescent products were isolated from the atherosclerotic lesions of the aged human artery. Ox-LDL was also intraperitoneally injected into guinea pigs to study an early stage of ceroid accumulation in macrophages. An early event in guinea pigs was the appearance of neutrophils. The findings from the model systems suggest that the ox-LDL in the artery wall is probable chemotactic for neutrophils as well as monocytes. We propose the hypothesis that the production of superoxide by neutrophils causes further lipid peroxidation of native LDL and then produces large amounts of oxidatively modified LDL which is the souse of ceroid pigment accumulated within the foam cells in human atherosclerotic lesions.

Aged↗
PubMed1995

Hermansky-Pudlak syndrome; a case report with analysis of auto-fluorescent ceroid-like pigments.

The Hermansky-Pudlak syndrome (HPS) is an autosomal recessive disease characterized by a triad of oculocutaneous albinism, accumulation of auto-fluorescent ceroid-like pigments within macrophages, and bleeding tendency due to a storage pool disease of the platelets. We report an autopsy case (39y, male), who died of pulmonary fibrosis and hemorrhage, with analysis of auto-fluorescent ceroid-like pigments (CLP). Pigmented macrophages were seen in almost all organs, especially marked in bone marrow, spleen, liver, colon, lymph nodes and kidneys. Ultrastructurally, CLP was intracytoplasmic electron-dense and -lucent congeries. Histochemical characteristics and auto-fluorescence of CLP showed similarities to ceroid. Substance which revealed brilliant lemon yellow autofluorescent was extracted from homogenized tissue of spleen with chloroform/methanol (2:1), then separated by thin-layer chromatography. The fluorescent substance had an excitation maximum at 360nm and a fluorescence maximum at 440nm, which is the same characteristic as described fluorescent lipid peroxidation products in vitro.

Adult↗
PubMed1995

[Sphingolipid changes in rat cerebral cortex during focal ischemia--how does ceramide accumulate in an ischemic condition?].

Levels of ceramide, sphingomyelin, cerebroside and gangliosides were determined in rat cerebral cortex during focal ischemia produced by middle cerebral artery occlusion. Ceramide began to increase at 6 hours of ischemia and increased to 4.5 folds at 96 hours. Amino-linked fatty acids in increased ceramide were composed solely of non-hydroxy fatty acids, and stearic acid was the most prominent. Sphingomyelin, whose amino-linked fatty acids were mostly stearic acid, decreased in a time-dependent manner and became about a half of controls at 96 hours. Hydroxy fatty acid linked cerebroside decreased at and after 6 hours of ischemia, whereas significant decrease of non-hydroxy fatty acid linked cerebroside occurred only at 96 hours of ischemia. There were no measurable changes in the levels of gangliosides. The results suggested that ceramide was produced in the cerebral cortex by the breakdown of sphingomyelin during ischemia.

Animals↗
PubMed1994

Conformational changes in oxidized LDL recognized by mouse peritoneal macrophages.

Mouse peritoneal macrophages have been considered to recognize and take up oxidized LDL by a scavenger receptor. However, it is still unknown what conformational changes in oxidized LDL contribute to recognition by the macrophage scavenger receptor. In the present study, it was shown that the amount of oxidized LDL taken up by macrophages correlated well with the fluorescence intensity formed in oxidized LDL. The autofluorescent products generated in oxidized LDL were characterized by Ex:365 nm Em:430 nm, and the intensity of the fluorescence was reduced at base pH, and restored by adjusting the pH to neutral. The characteristics of the fluorescent products indicate that a Schiff base structure was formed in oxidized LDL. Oxidized LDLs were fractionated into native size and aggregated large particles with HPLC by monitoring fluorescence. It was demonstrated that macrophages ingest selectively or preferentially aggregated oxidized LDL, but not native size oxidized LDL. The incorporation of aggregated oxidized LDL was remarkably suppressed by heparin and cytochalasin B. These results suggest that mouse peritoneal macrophages recognize the conformational changes in oxidized LDL related to the formation of a Schiff base structure with increasing autofluorescence, and ingest selectively aggregated large particles in oxidized LDL in a phagocytic process.

Animals↗
PubMed1991

Purine and pyrimidine compounds in murine peritoneal macrophages cultured in vitro.

Extracts of murine peritoneal macrophages were analysed by ion-pair reversed-phase high-performance liquid chromatography during incubation at 37 degrees C in vitro. Four-step gradient elution was applied to an ODS column (250 x 4.6 mm I.D.) at a flow-rate of 1.3 ml/min, allowing the separation of hypoxanthine, inosine, guanosine, adenosine, IMP, CDP, AMP, GDP, UDP, ADP, CTP, GTP, UTP and ATP within 50 min. Samples of 0.4 . 10(6)-0.5 . 10(6) cells were washed twice with RPMI 1640 medium and extracted with perchloric acid. Nucleotide concentrations of murine peritoneal macrophages did not change during incubation for 4 days in vitro.

Animals↗
PubMed1991

Free radical-induced liver injury. II. Effects of intraperitoneally administered 2,2'-azobis(2-amidinopropane) dihydrochloride on the fatty acid profiles of hepatic triacylglycerol and phospholipids.

Liver injury induced by the radical initiator, 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH) and carbon tetrachloride (CCI4) was examined by the analysis of lipids in the liver of rats. Increased triacylglycerol (TAG) was found in the liver within 24 hr following injection of these drugs. In AAPH-treated and CCI4-treated rats, it was 2.1 and 1.8 times that in the controls, respectively. TAG-palmitate and -oleate were found at particularly increased levels, while polyunsaturated fatty acid profiles of hepatic phospholipids were essentially the same for the treated and untreated rats. It is evident from these findings that radical initiators cause no decrease in polyunsaturated fatty acids in hepatic lipids, but accumulate TAG in the liver. Such a condition is the equivalent of liver injury in the rats in whose diets vitamin E has long been deficient.

Amidines↗
PubMed1991

Free radical-induced liver injury. I. Effects of dietary vitamin E deficiency on triacylglycerol level and its fatty acid profile in rat liver.

Effects of dietary vitamin E deficiency on the fatty acid compositions of total lipids and phospholipids were studied in several tissues of rats fed a vitamin E-deficient diet for 4, 6, and 9 months. No significant differences were observed between the vitamin E deficiency and controls except in the fatty acid profiles of liver total lipids. Triacylglycerol (TAG) accumulation was found in the liver of rats fed a vitamin E-deficient diet. The levels of TAG-palmitate and -oleate increased particularly in the liver from such animals. The fatty acid compositions of hepatic phospholipids were not affected by the diet. Increased TAG observed in the liver of rats fed a vitamin E-deficient diet was restored to normal when the diet was supplemented with 20 mg alpha-tocopheryl acetate/kg diet. These findings indicate that dietary vitamin E deficiency causes TAG accumulation in the liver and that the antioxidant, vitamin E, is capable of preventing free radical-induced liver injury.

Animals↗
PubMed1990

Accumulation of ceroid-like pigments in macrophages cultured with phosphatidylcholine liposomes in vitro.

When mouse peritoneal macrophages as well as P388D1 cells, an established macrophage-like cell line, were cultured with liposomes composed of rat liver phosphatidylcholine and phosphatidylserine, storage of fluorescent products, ceroid-like pigments, within those cells was observed with light and fluorescence microscopy, and fluorescence spectrophotometry. The amounts of thiobarbituric acid-reactive substances and fluorescent products in macrophages were increased gradually to reach a maximal level to between 6 and 8 days of culture. The involvement of peroxidation of liposomal lipids in the formation of the pigments was further suggested by the 6 days that incorporation of alpha-tocopherol into liposomes decreased the storage of the pigments. No appreciable formation of the pigments was observed in macrophages cultured with liposomes containing dipalmitoylphosphatidylcholine instead of rat liver phosphatidylcholine. The fluorescent products formed in cultured cells were found in lipid-soluble and -insoluble fractions. Lipid-insoluble fluorescent products had an excitation maximum at 360 nm and a fluorescence maximum at 430 nm in SDS-aqueous solution (pH 7.4) and the intensity of the fluorescence was quenched at base pH, but it was not changed in acidic media. These findings indicate that the macrophages can store Schiff base fluorescent substances formed by the reaction between peroxidation products of exogenous lipids and amino compounds in the cells, under some pathological conditions.

Animals↗
PubMed1990

Free radical-mediated chain oxidation of low density lipoprotein and its synergistic inhibition by vitamin E and vitamin C.

The oxidation of human low density lipoprotein (LDL) initiated by free radical initiator and its inhibition by vitamin E and water-soluble antioxidants have been studied. It was found that the kinetic chain length was considerably larger than 1, suggesting that LDL was oxidized by a free radical chain mechanism. Vitamin E acted as a lipophilic chain-breaking antioxidant. Water-soluble chain-breaking antioxidants such as ascorbic acid and uric acid suppressed the oxidation of LDL initiated by aqueous radicals but they could not scavenge lipophilic radicals within LDL to break the chain propagation. Ascorbic acid acted as a synergistic antioxidant in conjunction with vitamin E.

Ascorbic Acid↗
PubMed1990

Changes in cerebral free fatty acids and triacylglycerols in focal cerebral ischemia.

1. Focal cerebral ischemia was induced in anesthetized rats by occluding the stem of the proximal middle cerebral artery. 2. The levels of free fatty acids, such as stearic and arachidonic acids, in the ischemic cerebral cortex increased progressively until 60 min after occlusion, but thereafter they decreased rapidly. 3. In contrast to the time-dependent changes in free fatty acids, the levels of triacylglycerol (TAG) in the ischemic cerebral cortex continued to increase for 120 min after occlusion. Increases in TAG-palmitate, -stearate and -arachidonate accounted for the increase in the triacylglycerol level. 4. The pattern of the lipid changes in focal cerebral ischemia differs from those reported in bilateral diffuse cerebral ischemia induced by arterial occlusion or in decapitation ischemia.

Animals↗
PubMed1989

Lipid peroxidation and storage of fluorescent products by macrophages in vitro as a model of ceroid-like pigment formation.

Storage of fluorescent products, ceroid-like pigments was observed in P388D1 cells, an established macrophage-like cell line, when the cells were cultured in the presence of rat liver phosphatidylcholine liposomes containing polyunsaturated fatty acids. Some fluorescent products accumulated in the cells were extractable in organic solvents, ethanol/ether (3:1, v/v), while others were insoluble in organic solvents, but soluble in detergent. The fluorescent products dissolved in organic solvents or in detergent had a fluorescence maximum at 430 nm when excited at 360 nm. The formation of the ceroid-like pigments was inhibited, at least in part, by antioxidants, such as alpha-tocopherol and butylated hydroxytoluene (BHT). The fluorescence intensity of the pigments was quenched in alkaline media and restored by adjustment of pH to neutrality. These findings indicate that liposome uptake by macrophages causes the formation of ceroid-like pigments, and that the fluorescent chromophores of the pigments are Schiff base structures derived from the reaction of lipid peroxides from the exogenous phospholipids and subcellular amino compounds.

Animals↗
PubMed1989

Isolation of isoflavonoids possessing antioxidant activity from the fermentation broth of Streptomyces sp.

Three antioxidant isoflavonoids characterized as 4',7,8-trihydroxyisoflavone (1), 3',4',7-trihydroxyisoflavone (2) and 8-chloro-3',4',5,7-tetrahydroxyisoflavone (3) were isolated from the cultured broth of Streptomyces sp. OH-1049. Among them, 3 is a novel isoflavonoid possessing a chlorine atom in the molecule. In in vitro studies, these antibiotics were found to possess antioxidant activity whereas showed almost no cytocidal activities against HeLa S3 cells.

Animals↗
PubMed1989

Accumulation of ceramide in ischemic human brain of an acute case of cerebral occlusion.

An increase of ceramide, which is the major component of sphingolipids, was found in the ischemic human brain of an acute case of internal carotid artery occlusion. Amide-linked fatty acids in the ceramide isolated from the ischemic human brain were mostly non-hydroxy fatty acids, such as stearic acid (66.9%) and palmitic acid (20.2%). Other long-chain fatty acids, C24:0 and C21:1, were rare components in the ceramide. The ceramide contained C-20 sphingosine, and the ratio of C-20 to C-18 was 0.13. These findings indicate that an ischemic insult accelerates the degradation of gangliosides and causes an accumulation of ceramide in the ischemic human brain.

Aged↗
PubMed1988

Morphometrical and biochemical analysis on autofluorescent granules in various tissues and cells of the rats under several nutritional conditions.

The effects of age and nutritional conditions on accumulation of autofluorescent granules in various organs and tissues of male Sprague-Dawley rats were compared morphometrically. The relative intensity of the specific fluorescence of these autofluorescent granules was similar in all tissues and cells examined. In almost all cases, there were more autofluorescent granules in the 12-month experiment than in the 4-month one. Multiple necrotic foci of myofibrils with an accumulation of autofluorescent granules were seen in striated muscles in the rats on vitamin E-deficient diets for 12 months. In splenocytes, renal proximal convoluted tubules and hepatic cells, autofluorescent granules quantitatively increased significantly with an increase of the corn oil contents in the diets. The increase was rather marked in the splenocytes and renal epithelia of vitamin E-deficient rats. In the Purkinje cells and bronchial epithelial cells, no significant differences were noted according to the difference in the vitamin E and corn oil contents in diets. The accumulation of autofluorescent granules was not merely considered to be an age-related change, but to be influenced by a relationship to the cell metabolism and functional activity in various organs.

Animals↗
PubMed1988

Comparison of fluorescence characteristics of products of peroxidation of membrane phospholipids with those of products derived from reaction of malonaldehyde with glycine as a model of lipofuscin fluorescent substances.

The fluorescence characteristics of product (I), formed during the lipid peroxidation of rat liver phosphatidylcholine liposomes containing glycine, and fluorescent product (II), derived from the reaction of malonaldehyde with glycine, were examined to elucidate the mechanism of fluorescent chromophore formation. Fluorescent product (I) had a fluorescence emission maximum at 430 nm when excited at 360 nm; its fluorescence intensity decreases in alkaline medium, but is restored by readjustment of pH to neutrality. In contrast, fluorescent product (II) exhibited an emission maximum at 458 nm, and the fluorescence was quenched at acidic pH. The fluorescent substances formed during the lipid peroxidation of hemoglobin-free human erythrocyte ghost membranes had similar fluorescence characteristics to product (I). Gel filtration experiments showed that molecular size of fluorescent product (I) was larger than that of fluorescent product (II). The thiobarbituric acid-reactive substances released from peroxidizing liposomal phospholipids had a larger molecular size than malonaldehyde, and produced little or no fluorescence with glycine. It is concluded that the precursor of the fluorescent product formed during the lipid peroxidation of membrane phospholipids differs from malonaldehyde. The mechanism of the formation of blue emitting fluorescent material, believed to be a component of lipofuscin, seems to involve peroxidized phospholipids of the membrane.

Animals↗