Hirobumi Metoki

Acceleration of platelet aggregability due to modulation of native LDL.

The aim of this experiment was to clarify whether low density lipoprotein (LDL) causes an acceleration of platelet aggregability. Native LDL was separated into two fractions by filtered tap-water dialysis, namely, water-soluble LDL (WS-LDL) and non-water-soluble LDL. Although native LDL did not enhance the platelet aggregability, WS-LDL made it markedly increased. WS-LDL consisted of the lipid constituents that were not found in native LDL. Namely, in thin-layer chromatography of WS-LDL, an unknown spot between triolein and free fatty acid was clearly stained. This unknown spot in the WS-LDL was produced by the peroxidation of cholesteryl ester in native LDL. It was confirmed that the spot has the same Rf value as the peroxidate of cholesteryl linolate in thin-layer chromatography. If native LDL is modulated by divalent metal ions and oxygen in the fluids, LDL with biological activity such as an increase of platelet aggregability is produced.

A new approach to prevention and treatment of atherosclerosis by dyslipoproteinemia.

A number of papers’.’ have been published on the treatment and prevention of atherosclerosis. The main points of those papers were to reduce the concentrations of low density lipoprotein cholesterol (LDL-CH), apoprotein B (apo B), and lipid peroxide (LPO) or to increase that of high density lipoprotein cholesterol (HDL-CH). Furthermore, in several human and nonhuman primate experiment^^.^ it was shown that atherosclerotic lesions regressed by reducing the concentration of LDL-CH for an extended period of time. Recently, Steinberg’ and Kitah reported that the foramtion of atheroma was suppressed in WHHL rabbits by probucol treatment. They pointed out that the suppression of LPO was more important for the treatment and prevention of atherosclerosis than the reduction of LDL-CH. In this paper, new aspects for the treatment and prevention of atherosclerosis will be discussed from the viewpoint of the composition and physical character of LDL.

Comparison among lipid constituents in native LDL, ultra-water-soluble LDL, and vessel wall, and their significance in arteriosclerosis

The lipid constituents in native low-density lipoproteins (LDL), ultra-water-soluble LDL (UWS-LDL), and aortic intimal tissues were compared. These lipoproteins were obtained from healthy persons and patients with atherosclerotic diseases. Also, aortic intimas were separated from arterial walls obtained within 5 hr after the donors death. (1) From the native LDL, cholesterol esters (CE), triglycerides (TG), small amounts of free fatty cid (FFA), free cholesterol (CF), and phospholipids (PL) were demonstrable by iodine vapor on TLC, but from UWS-LDL the above lipids plus a new lipid (spot X) were observed between TG and FFA on TLC. And also, an unknown spot with the same Rf value as spot X was recognized on TLC of lipid extract from the atherosclerotic lesion, but not from the normal intima. (2) The production of spot X in UWS-LDL is probably related to the oxidation of lipids in native LDL. Also, the spot X in UWS-LDL and the spot X in the atherosclerotic lesions are probably related to the oxidation of CE in these lipids. (3) The existence of UWS-LDL is important to the initiation and probably the progression of atherosclerosis.

Peroxidized low-density lipoprotein with four kinds of hydroperoxidized cholesteryl linoleate estimated in plasma of young heavy smokers.

AIM To clarify the mechanisms of vascular complications due to heavy smoking, it was studied whether hydroperoxidized low-density lipoprotein (HPO-LDL) was estimated in plasma of young heavy smokers. METHOD Plasmas were separated from 15 young male students (HS-M) who smoked more than 30 cigarettes/day over 5 years, and from 10 nonsmoker students (NS-M) too. LDL was isolated by ultracentrifugation. HPO-cholesteryl linoleate (HPO-CL) was identified by thin-layer chromatography (TLC), and lipid peroxide was measured by Determiner LPO (Kyowa Medics Co., Ltd, Tokyo, Japan). The molecular structure of lipid peroxide in LDL was identified using GMS analysis, HPLC chromatography and 1H-NMR analysis. RESULTS (1) HPO-CL was clearly observed on the TLC in LDL lipids of HS-M but from NS-M it was barely found. (2) Lipid peroxide in LDL separated from HS-M consisted of HPO-CL and reduced HPO-CL. CONCLUSION Peroxidized LDL was estimated in plasma with young heavy smokers. Because of injurious reactions in vessels of peroxidized LDL, it is considered that heavy smoking is one of the risk factors for vascular complications in heavy smokers.

Sodium ionophore converts growth manner of vascular smooth muscle cells from spontaneously hypertensive rats.

OBJECTIVES Vasoconstrictor peptides such as endothelin (ET) cause hypertrophy of vascular smooth muscle cells (VSMC) in Wistar Kyoto rats (WKY) and hyperplasia in spontaneously hypertensive rats (SHR). They also induce an increase in Na+ concentration ([Na+]i) and activate protein kinase C (PKC) independently. Therefore, we tested the hypothesis that the increase in [Na+]i may be involved in the conversion of growth manner under activated PKC in SHR VSMC. METHODS AND RESULTS 10(-7) M phorbol ester (TPA) increased the diameter and protein content of VSMC from both strains under 18% serum conditions. Further addition of 10(-6) M gramicidin (Na+ ionophore) converted TPA-induced hypertrophy to hyperplasia, which was due to the quick transition from S to G2/M phase, only in SHR VSMC. Western blot analysis showed that serum- and TPA-induced tyrosine phosphorylation of mitogen-activated protein (MAP) kinase was potentiated by 10(-6) M gramicidin in SHR. [Na+]i, which was measured by sodium-binding benzofuran isophthalate (SBFI), was increased about 35 mM by 10(-6) M gramicidin in both strains, but TPA did not affect basal [Na+]i and the gramicidin-induced increase in [Na+]i. CONCLUSIONS We conclude that sodium ionophore may convert hypertrophy to hyperplasia synergistically with activated PKC in SHR VSMC, possibly by MAP kinase phosphorylation.

Endothelial Cell Injuries by an Infusion of Various Low Density Lipoproteins into the Rabbit Auricular Vein

Three-month-old white rabbits weighing 3 kg were used for the study. LDL was separated by Havel’s method. ’ The rabbits were divided into four groups by the kinds of feeding, namely, group 1, standard food; group 2 , group 1 + 1% cholesterol; group 3, group 2 + 2% probucol; and group 4, group 2 + 10% soycream (soycream was made from soybeans). LDL which was separated after feeding with each food for 5 weeks, was infused into the rabbit auricular vein. The concentration of the infused LDL was diluted to normal serum cholesterol level, and 400 ml of this diluted LDL were infused into the vein at a rate of 2.2 mumin for 3 hours. Similarly, LDL separated from the rabbits of the four groups was diluted to the same concentration, and the same amount was infused. Cerebral basilar arteries were observed by scanning electron microscope and transmission electron microscope,* and the findings were compared among the four groups. Platelet aggregability was measured by Born’s m e t h ~ d . ~

Chemical Characterization of Peroxidized Low-Density Lipoprotein in Plasma and Aortic Atheroma

Hydroperoxidized cholesteryl linoleate (HPO-CL, spot X1 ) was produced by peroxidation of normal LDL isolated from plasma of healthy persons. Spot X1 stained on

Chemical characterization of peroxidized low density lipoprotein(LDL) in plasma and aortic atheroma

Hydroperoxidized cholesteryl linoleate (HPO-CL, spot X1) was produced by peroxidation of normal LDL isolated from plasma of healthy persons. Spot X stained on thin-layer chromatography plate (silica 60) between triglycerides and free fatty acids. The solvent mixture used consisted of petroleum ether 75, ethyl ether 25, and acetic acid 1. Spot X1 of plasma from healthy subjects stained slightly. It was also identified in plasma LDL of patients with atherosclerotic diseases, and in total lipids extracted from aortic atheroma obtained at autopsy. Whereas spot X1 obtained from plasma LDL of patients with atherosclerotic diseases consisted of HPO-CL, spot X1 obtained from aortic atheroma was reduced HPO-CL (hydroxide CL). Spot X1 of obtained from aortic atheroma was reduced HPO-CL (hydroxide CL). Spot X1 of aortic atheroma did not react to p-methoxydiphenylpyrenylphosphine (MP3)-an agent which shows only positive reaction to hydroperoxide chemical structures-although spot X1 of plasma LDL from atherosclerotic diseases reacted positively to MP3. Moreover, spot X1 obtained from aortic atheroma showed the same Rf value as that of the reduced HPO-CL. The IR profile of spot X1 obtained from aortic atheroma was similar to that of hydroxide CL, although the IR profiled HPO-CL was similar to that obtained from plasma LDL of atherosclerotic patients. In addition, HPO-CL was not recognized in the LDL fraction with clathrin-coated pits from aortic atheroma.

Eleven cases with chilaiditi's syndrome in stroke patients.

昭和50年1月より昭和62年3月までの13年間に当院へ入院した脳卒中患者2,588例中に11例のChilaiditi症候群が認められた.男性7例, 女性4例, 発症時平均66.4±6.6歳であった.発症率は0.43%であり, 一般の集団検診における発症率より高く, 本症候群と脳卒中との関連が示唆された.全例とも特有の症状はみられず, 定期的な胸部X線写真により発見された.消化管の嵌入は一過性の場合が多く, その部位は総て結腸であった.発症の背景として, 全例に片麻痺があり, 頭部CT像および脳波から高度の脳機能障害の存在が推察された.100gGTT正常例は2例のみであった.腹部の合併症は, 胆石症と十二指腸潰瘍があり, 抗コリン剤の使用は2例であった.脳卒中発症から本症候群発症まで平均24.2±10.8ヵ月が経過しており, 長期のリハビリテーション治療を必要とする症例が多かった.成因として, 高度の脳機能障害による横隔膜および腸管の運動異常, および日常生活動作の著明な低下による腸管運動の低下などが考えられた.

A case of SIADH caused by hemorrhage in the right caudate nucleus

ADH分泌異常症候群 (SIADH) の誘因として中枢神経系疾患はよく知られているが, 脳血管障害は稀であるといわれている.著者らは脳血栓症患者が尾状核頭出血の併発後, 約1ヵ月間低Na血症を呈した症例を経験した.症例は67歳, 男性.主訴は左片麻痺.昭和53年10月14日脳血栓による左不全麻痺が発症し, 以後2回の脳血栓再発作と頻回のTIAを繰り返していた.抗凝固剤投与中, 昭和56年3月31日右尾状核頭出血発症.頭部CTscan.で側脳室及び第3脳室への穿破が確認された.検査成績は, 血清Na122rnEq/l, 尿Na5.2g/日, 血清及び尿浸透圧262mOsm/l, 440mOsm/l, 血液pH7.48, PRA5.Ong/ml/hr, 血中ADH 1.5Pg/ml.高張食塩水500ml/日投与したが低Na血症は改善されなかった.PRAの上昇は降圧利尿剤の使用によるもので, SchwartzらのSIADHの診断基準に矛盾する点はなかった.血中ADHは低Na血症の改善開始時に採血され, 正常範囲であったが, 本症例は尾状核頭出血によりSIADHが併発されたものと考えられた.