Effects of energy restriction diet on heterozygous familial hypercholesterolemia were studied. The choline esterase activity was well correlated with T. cholesterol, and also correlated with intake calory. During intake energy restriction (24Kcal/Kg/day), serum T, cholesterol levels lowered by 43 and 76mg/dl at 4 weeks and 8 weeks respectively. Choline esterase was also decreased. The responders for intake energy restriction could be defined from initial choline esterase activities and the expected cholesterol level controlled by energy restriction was obtained as follow; T, chol. -50×(Ch. E-6). Isocaloric low fat diet (P:F:C=30:15:65) for 2 weeks lowered T, cholesterol by 10%.

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Effects of a thromboxane synthetase inhibitor was studied in an experimental model of acute myocardial infarction. Intracoronary thrombus was precipitated by a mock atheromatous plaque in 13 of 15 control dogs.
Myocardial infarction was induced in 10 of them and sudden death in 2.
There were 2 types of reduction of the coronary blood flow due to thrombus formation: a gradual decrease associated with the delayed appearance of abnormalities in myocardial contraction and the electrocardiogram in 7 of the 12 dogs with myocardial infarction or sudden death (Type A) and repetition of the alteration of reduction and sudden increase in coronary blood flow in the remaining (Type B). In either type, coronary blood flow decreased to induce myocardial infarction in 212±41 minutes.
Thromboxane B₂ and 6-keto-prostaglandin F_1α were significantly elevated in the coronary venous blood during the reduction of the coronary blood flow.
The model was utilized to investigate the effects of a selective thromboxane synthetase inhibitor, OKY-046, on an additional 10 dogs. OKY-046 could significantly interrupt the occurrence of myocardial infarction when administered intravenously during Type A or B reduction of the coronary blood flow (3/10 vs. 12/15, p<0.02). A significant reduction in thromboxane A₂ appeared to be the major mechanism of the interruption of the thombus formation and completion of myocardial infarction.

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Antiaggregatory properties of the prostacyclin analogue Iloprost were investigated in relation to cyclic AMP levels in the pig platelets. Dosedependent cyclic AMP accumulation in response to Iloprost was noted with the ED₅₀ being 9.2×10^-8M, which was similar to the IC₅₀ for the inhibition of collagen-induced aggregation by Iloprost. Iloprost significantly suppressed thromboxane A₂ release from the platelets induced by collagen, determined as thromboxane B₂ by radioimmunoassay. Phosphodiesterase inhibitors, such as IBMX, Milrinone or Dipyridamole, markedly enhanced cyclic AMP accumulation in response to Iloprost in the platelets and potentiate antiaggregatory property of the agent.
These results suggest that combined therapy of Iloprost with phosphodiesterase inhibitors may be of benefit in the clinical setting.

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The suppressive effect of porcine pancreatic elastase on experimental atherosclerosis was examined. Three groups of rabbits were studied for 53 weeks: one control group and two groups on a 1% cholesterol diet. Of the cholesterol-fed groups, one group received the 1% cholesterol diet alone, and the other group was administered intramuscularily with porcine pancreatic elastase (Eisai Co. Ltd., 10mg/rabbit/day).
The enzyme activity in sera of the three groups toward Suc-(Ala)₃-pNA, a synthetic substrate of elastase, was significantly higher in elastase-treated rabbits for periods of 53 weeks. We estimated this activity as an elastase activity because elastatinal, a specific inhibitor of elastase, strongly inhibited the enzyme activity in sera of elastase-treated rabbits as well as the activity of porcine pancreatic elastase used for administration.
Treatment with elastase suppressed the elevations of serum cholesterol and triglyceride levels and calcium concentrations induced by the cholesterol diet. Rabbits given the cholesterol diet without elastase had a high content of cholesterol, triglyceride and calcium in aortic elastin as well as in aortic tissue. However, in rabbits treated with elastase, these components in both aortic tissue and elastin were reduced markedly, especially in elastin. A content of aortic elastin decreased in rabbits fed the cholesterol diet without elastase, but was restored in rabbits treated with elastase. Amino acid compositions of the isolated elastin preparations from aortas of untreated rabbits on the cholesterol diet showed a marked increase in polar amino acids and a significant decrease in cross-linking amino acids. However, treatment with elastase suppressed these changes in amino acids in elastin.
In microscopic studies on aortic media of the three groups, as compared to control rabbits, rabbits receiving the cholesterol diet without elastase showed not only severely deranged and fragmented elastic fibers but also heavy accumulations of calcium and lipids on the damaged elastic fibers. However, in rabbits treated with elastase, elastic fibers were almost normal and there was little accumulation of calcium and lipids on these elastic fibers except for a few deposits of calcium and lipids around the internal elastic lamina.
It was demonstrated from these biochemical and morphological studies that treatment with elastase resulted in a marked suppression of atherosclerosis. In particular, the prevention of alteration of elastin may play an important role in the antiatherogenic effect of elastase.

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An investigation was undertaken in order to elucidate the pathogenesis of atherosclerosis, focusing attention on the relationship between elastin and artery wall constituents.
<Results›
1. Gross and Histological Examination of Thoracic and Abdominal Aortas
Whereas the experimental atherosclerosis group (Group A) had marked elastic fiber destruction and calcification, there was a tendency in the elastase group (Group AE) that such changes were inhibited. Further, the development of atherosclerotic changes was inhibited in the group receiving both elastase and a Ca²⁺-antagonist. In electron micrographs it was plain that rats of the elastase group had less foam cells but more mitochondria and endoplasmic reticulum in smooth muscle than control animals. Further, in the former group myofilaments were formed in artery smooth muscle and microfibrils and amorphous components were present around smooth muscle cells.
2. Cell Proliferation and Elastin Production in Cultured Smooth Muscle Cells of the Aortic Intima
Smooth muscle cell division and proliferation was inhibited in the elastase group unlike in the control group, and the content of desmosine was significantly higher in the elastase than in the control group.
<Conclusion›
The results of this study have led us to the postulate that elastase stimulates smooth muscle cells of the aortic intima to produce elastin so that fibrillogenesis in the elastic fiber is promoted.

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Migration of smooth muscle cells from the media into the intima of the artery to proliferate has been regarded as a primary key event in the morphogenesis of atherosclerosis. Metabolism and functions of vascular smooth muscle cells seem to be deeply influenced by their phenotypes, contractile or synthetic type. Intimal smooth muscle cells obtained from atherosclerotic plaques of animals placed on atherogenic diets exhibited more frequently synthetic phenotype, which is characterized by not only abundant rough surfaced endoplasmic reticuli, free ribosomes and mitochondria but scanty myofilaments, than normal medial smooth muscle cells in vivo and vitro. The former cells showed higher rates of DNA-, collagen- or prostacycline-synthesis and higher activity of various lysosomal enzymes than the latter cells.
In order to disclose the time of the phenotype change at migration, we investigated fine structures of the smooth muscle cells regarded as migrating from the media into the intima, based upon a morphological finding in which cells stretched into the intima through fenestrae of the internal elastic lamella. Out of fourteen migrating cells, 12 cells showed the contractile type in the part of their cytoplasms still remaining in the media, and simultaneously synthetic type in their cytoplasms reached in the intima. There were also few basement-membrane like substances accompanied with the migrating cells, particularly around the medial part. Thick and intermediate filaments were observed more frequently in the intimal part than in the medial part of cytoplasm of the migrating cell.
Finally we could draw the conclusion that change of phenotype of arterial smooth muscle cells migrating occurred within a short period after reach in the intima.

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Reduced prostacyclin (PGI₂) production by the vascular wall can cause platelet hyperaggregation, which is considered to be one pathogenesis of diabetic angiopathy. In the present study, we confirmed a stimulatory activity on PGI production (PGI₂ stimulatory activity; PSA) in rat and human plasma derived serum (PDS) by cultured bovine aortic endothelial cells (EC) and rat lung fibroblasts (FB). Furthermore, the abnormality of PSA was studied in streptozotocin-induced (STZ) diabetic rats and human noninsulin-dependent diabetic patients (NIDDM) using these in vitro systems.
Cultured EC and FB were incubated with DME medium containing rat and human PDS. After incubation, the concentration of 6-keto-PGF_1α (a stable metabolite of PGI₂) in the medium was assayed by RIA. 6-keto-PGF_1α production by cultured EC and FB was stimulated by the addition of rat and human PDS in a time and dose dependent manner. The addition of 10% PDS from STZ diabetic rats or NIDDM showed a significant decrease in 6-keto-PGF_1α production by cultured EC and FB as compared with that from controls. These findings suggested that PSA in PDS decreased in both STZ diabetic rats and human NIDDM. In addition, the reduced PSA was also present in NIDDM without diabetic vascular complications as well as NIDDM with vascular complications. Furthermore, the difference in PSA between NIDDM and controls still remained in PDS treated with dialysis. It is concluded that the decreased PSA in PDS can cause the reduction of PGI₂ production by the vascular wall and play an important role in the pathogenesis of diabetic vascular complications.

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Several investigators have reported the decreased PGI₂ synthesis by arteries obtained from atherosclerotic animals and patients with atherosclerosis. In contrast to those results, FitzGerald et al, have suggested the increased PGI₂ production in atherosclerotic patients in vivo by measuring their increased PGI₂-metabolite in urine. On the other hand, the proliferative growth of SMC in intima has been shown to play an important role in the process of atherosclerosis because of its increased capability to produce PGI₂.
Therefore, we reexamined in vitro PGI₂ synthesis by aortic explants of thoracic aorta obtained from atherosclerotic rabbit fed a cholesterol rich diet for 4 months. Aortic explants weighing about 10-20mg were incubated in 1ml of KRB-glucose buffer (pH 7.4), for 30 min at 37°C. Aortic SMC were also obtained from medial explants of normal rabbits (thoracic aorta) and from Intimal explants of atherosclerotic rabbits and then cultured in DME medium supplemented with 10% FCS, routinely. PGI₂ levels in incubation media and culture media were determined as 6-keto-PGF_1α by RIA after extraction and separation as reported previously.
Both basal and arachidonic acid-induced productions of PGI₂ by aortic explants from atherosclerotic aorta were significantly higher than those of controls. Furthermore, cultured intimal SMC obtained from atherosclerotic rabbit aorta produced a significantly greater amount of PGI₂ than medial SMC from normal rabbit aorta under various conditions examined. Therefore, the present data further suggest that intimal growth of SMC may play a pivotal role in the process of atherosclerosis.

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The cellular origin and development of early intimal lesions of rabbits fed a cholesterol diet for 8 to 12 weeks were studied morphologically and analyzed for several features of macrophage properties.
Scanning and transmission electron microscopic observations demonstrated a large number of circulating cells attached to the endothelial surface and the number of these which appeared to be migrating across the endothelium. Early fatty lesions were characterized by accumulations of fat-filled foam cells in the intima accompanied by appreciable numbers of blood-derived cells, notably monocytes, lymphocytes and polymorphonuclear leukocytes. Transitional sequences from the monocytes to the lipid-containing macrophages or foam cells were discerned. According to the method of Schaffner et al., foam cells were isolated from suspensions by substrate adherence to analyze the presence of authentic Fc and C3 receptors, immune or nonimmune phagocytic capacity, or to perform cytochemical examination. Easily dislodged plastic-adherent cells were filled with oil red O-positive granules and showed remarkable staining for nonspecific esterase. More than 90% of these plasticadherent cells had Fc receptors, whereas about 80% of them possessed C3 receptors. Attached erythrocytes were rapidly phagocytized. Ultrastructural observation of rosette-forming cells confirmed several features compatible with foam cells derived from macrophages. In addition, these cells exhibited phagocytosis of yeasts with or without pretreatment with normal rabbit serum. Among the cells migrating from the explants, a population of round cells revealed properties of macrophages such as positive nonspecific esterase activity, surface receptors, and phagocytosis of coated erythrocytes. The results indicate that foam cells, which characterize the early atherosclerotic plaques of cholesterol-fed rabbits, possess structural and functional properties of macrophages. It seems likely that circulating monocytes are the prime source of foam cells in the early phase of atherogenesis.

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1) Atherosclerotic aortic intimas of cholesterol-fed rabbits were enzymatically dispersed into single cells by collagenase and elastase. And macrophages were separated from smooth muscle cells, using the ability of Mφ to adhere to a plastic dish firmly even in the enzyme solutions.
(2) Macrophage-derived foam cells (Mφ-FC) showed very strong activity for non-specific esterase by α-naphthyl butyrate, while smooth muscle cells showed little or no activity. This method will be useful to estimate the purity of the separated Mφ-FC.
(3) Some of the Mφ-FC were large and multinucleated (we call them giant multinucleated foam cells).
4) Mφ-FC produced various prostanoids into the medium (PGE₂>6-keto PGF_1α>TXB₂>PGF_2α).
5) Mφ-FC did not proliferate in DMEM+10% FCS. They gradually died and the number of cells decreased.
6) Almost no Mφ-FC were obtained from the intima-medias of grossly normal portions of atherosclerotic aortas and control aortas.
(7) This method of separating Mφ-FC from atherosclerotic lesions will be useful for studying the role of Mφ in atherosclerosis.

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To study the mechanism of cholesterol deposition in the monocyte-macrophage (foam cell formation), we incubated peritoneal macrophages from normal and Watanabe heritable hyperlipidemic (WHHL) rabbits with various types of lipoprotein. Rabbit macrophages were induced by intraperitoneal injection of liquid paraffin oil. Each dish contained 2×10⁶ adherent cell which had characteristics of macrophage. After 18 hours incubation with DMEM, mechanism of lipoprotein uptake was investigated by reacylation reaction of [¹⁴C]oleate with cholesterol and degradation of ¹²⁵I-labeled lipoproteins. When incubated with normal rabbit macrophages for 5 hours, 50μg/ml of human LDL, acetyl LDL, and rabbit β-VLDL stimulated the cholesteryl [¹⁴C]oleate synthesis of 30, 15, and 35nmol/mg protein, respectively. On the other hand, macrophages from WHHL rabbit showed different response. About 0, 15, and 24nmol/mg protein of cholesteryl [¹⁴C]oleate was synthesized by WHHL macrophages. When 50μg/ml of ¹²⁵I β-VLDL was incubated with macrophages from normal and WHHL rabbit for 5 hours, ¹²⁵I β-VLDL was degraded by saturable high affinity mechanism. Each macrophage degraded 11.5 and 3.2μg/mg protein of ¹²⁵I β-VLDL, respectively. This β-VLDL degradation was inhibited only by excess β-VLDL. These data suggest the existence of the receptor specific to β-VLDL. We have already reported that cholesterol rich very low density lipoprotein from WHHL rabbit stimulates cholesteryl ester synthesis in mouse peritoneal macrophages via β-VLDL receptor. Considered together, macrophages from WHHL rabbit may accumulate cholesteryl ester by taking up cholesterol rich VLDL via their β-VLDL receptor, and this mechanism may be responsible for atherogenesity of patients of homozygote FH.

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The histological findings in the subendothelial lesions of coronary arteries were observed in 14 autopsy cases who had a clinical history and ECG changes of unstable angina at rest within a month of death. 308 cross-sections (2 from each 11 segments from each heart) obtained from the cases were examined and compared with 616 sections from 28 controls who had no anginal history and ECG changes within a month of death.
Of the 308 sections from the anginal group, 76 (24.7%) were narrowed 76% to 100% by atherosclerotic plaque (control; 4.5%) and 32 (10.8%) had occulusive thrombi (control; 0%). In the subendothelial space of thickened coronary intima, the infiltration of mononuclear cells (i. e. monocytes, macrophages and foam cells) with edematous changes was present, and more frequent in the anginal group (30.4%) than the control (8.1%, p<0.01). These findings in the coronary subendothelial space may be a feature of increased endothelial permeability due to coronary vasospasm, and the repeated spasms may result in progression of coronary atherosclerosis.

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The effects on fibrinolysis of purified normal human high density lipoproteins (HDL) and their apolipoproteins (apo) were assessed in an in vitro system containing urokinase, plasminogen and fibrin. HDL significantly increased lysis area of plated fibrin compared to controls. The hydrolysis of a chromogenic substrate (S-2251: H-D-Val-Leu-Lys-pNA) specific to plasmin or urokinase activated plasminogen was higher in the presence of apo A-I, apo HDL₂, and apo HDL₃. These data suggest that the major protein of HDL—apo A-I— and possibly certain minor apo constituent(s) of HDL may participate in the fibrinolytic process and propose a new function for HDL.

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Patients, who had suffered from cerebral thrombosis more than a month before and were in chronic state, were randomly divided into 2 groups. In group 1 they were first administered cinepazide malate for one month, which hardly inhibited platelet aggregation, and followed by an addition of a low dose of aspirin (50mg/day) for a further one month. In group 2 both drugs were administered in the reserve way; namely, at first the low dose of aspirin for one month and then cinepazide malate additively for a further one month. Platelet aggregability was checked by use of lumi-aggregometer and when the inhibitory effect on the aggregability was still inadequate, 50mg of aspirin were added every week untill the platelet aggregation decreased to the adequate level. A neurologist who was not informed about the trial schedule evaluated the clinical signs and symptoms of each patients in detail at the fixed intervals.
The results were as follows:
1) In most patients, platelet aggregability was adequately inhibited by a low dose of aspirin (50mg/day).
2) It was suggested that drugs improving cerebral circulation were clinically more useful if they had simultaneously the inhibitory effect on platelet aggregability.

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Controversy exists as to whether atherosclerotic lesions were reversible or not. These conflicting views mainly derived from differences of animal species, experimental designs, or methods of evaluation. In the present study we attempted to quantitate sequential changes of sclerotic lesions with an aid of the image processing system.
Normotensive and renovascular-hypertensive rabbits were placed on a 0.5% cholesterol diet for 16 weeks and observed up to 120 weeks. After measuring surface involvement (SI) by the point counting method, a representative longitudinal section covering the whole length of the aorta was obtained, and histometric quantitative analysis was carried out concerning foam cell infiltration, fibromuscular proliferation, and atheroma formation. In addition, 10 continuous step sections of the left coronary artery (and its branches) was prepared, and the degrees of luminal stenosis were estimated in all arterial segments contained in the sections.
After stopping of cholesterol feeding, foam cell lesion of the aorta and coronary artery was gradually replaced by fibromuscular tissue. A greater degree of smooth muscle cell proliferation was a feature of hypertensive animals. Formation of atheroma occurred almost invariably after 12 weeks return to the normal diet. It was noted that hypertension accentuated the severity and extent of both aortic and coronary lesions.
Evidence of regression of nonatheromatous as well as atheromatous lesions was obtained in normotensive rabbits (and partially in hypertensive rabbits) sacrificed after 44 weeks return to the normal diet. Significant reduction of coronary lesions with luminal narrowing of more than 60 % were also documented in both normotensive and hypertensive animals. In conclusion, the present study indicated that, even in the hypertensive animals, regression of both aortic and coronary lesions of the rabbits could occur following a long period of dietary manipulations. The extent of regression, however, appeared to be less prominent, when compared with several observations demonstrated in monkeys.

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The receptor for acetyl low-density lipoprotein (Ac-LDL) was partially purified from rat liver membrane. Using 40mM octyl-glucoside buffer, Ac-LDL receptor was solubilized from liver membrane, and was partially purified using maleyl bovine serum albumin affinity column, which is a potent inhibitor of Ac-LDL binding. The K_d for membrane or partially purified receptor was about 3-4μg/ml. The receptor had apparent Mr. 249, 000 and pI 6.1.

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Recently, a new method for measuring serum lipid peroxide (LPO) has been developed. Reaction between lipid hydroperoxide and a derivative of methylene blue (MCDP; 10-N-Methylcarbamoyl-3, 7-dimethylamino-10 H-phenothiazine) produces methylene blue, by which serum lipid peroxide can be calculated. By using this new method, (1) we tried to determine the values of serum LPO in healthy subjects and in patients with various diseases, and (2) we also investigated the distributions of LPO in serum lipoprotein fractions, separated by high performance liquid chromatography (HPLC). Results were as follows;
(1) In healthy subjects, LPO level was 7.63±2.78nmol/ml. The level in patients suffering from cerebrovascular accidents (mainly in acute phase) was lower than in healthy subjects, while the levels in patients with hypertension and hyperlipidemia were higher. (2) By HPLC, only one peak of LPO was detected. This peak was possibly located in HDL-fraction, and there were no detectable peaks in LDL-fraction.
There have been several reports on the detection of LPO in lipoprotein fractions, which said, in contrast to our results, that high levels of LPO were found in two fractions, i.e. both LDL- and HDL-fractions. This difference might be due to the differences in analytical methods. Those reports used ultracentrifugation technique for lipoprotein separation, and TBA method for LPO detection. There exists a possibility that ultracentrifugation technique denatures lipoproteins. In our experiment, it is unlikely that the peak was located in LDL-peak, judged from the elution pattern. However, whether this peak was located in HDL-peak is now under investigation. Our new analytical technique is the combination of HPLC and the new method of LPO detection, and, in this system, we observed only one peak of LPO. Further investigation is needed to clarify the quality and the quantity of distribution pattern of serum LPO.

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Effects of mild exercise therapy on serum lipids (TC, TG), HDL subfraction (HDL₂ and HDL₃) and apoproteins (apo A-I, A-II, B, C-II, C-III and E) were examined in ten patients with essential hypertension and age, sex-matched nontraining hypertensive controls (n=10). Mild exercise program consisted of the exercise intensity of work load at first braking point of lactate (WBPLA₁), 60minutes/time and 3times/week for 10 weeks. Significant reduction of blood pressures was observed by 4, 7, 10th week following initiation of exercise therapy, while no significant change was found in the nonexercise hypertensive controls. Serum concentration of HDL₂-cholesterol increased significantly after 4, 7, 10th week, while no significant change was observed in total HDL-cholesterol levels. No significant changes were found in serum concentrations of total cholesterol, triglyceride and apoproteins following 10 weeks of exercise therapy program.
In conclusion, it is suggested that mild exercise training not only depress blood pressures but also improve lipoprotein profiles.

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Acute effect (1 hour after administration) and the effects for relative short periods of cholestyramine on the cholesterol and triglyceride levels of plasma and lipoprotein fractions, apolipoprotein levels, and platelet aggregation were studied in 13 male healthy volunteers (25.5 year old in average, ranged from 22 to 29 year old).
After 10 days administration of cholestyramine (12g/day, 3 tid), total, VLDL- and LDL-cholesterol were significantly decreased, while the HDL-and HDL₂-cholesterol were significantly increased. Cholestyramine also had the effect of the reduction in the total and LDL-cholesterol, and increase in the HDL-cholesterol even 1 hour after the administration. On the other hand, there were no significant changes of plasma triglyceride both at 1 hour after the administration of cholestyramine and 10 days for the administration of cholestyramine.
The apolipoprotein B level was significantly decreased, while there were no significant changes of other apolipoprotein levels for the 10 days administration of cholestyramine.
There were no effects of cholestyramine on platelet aggregation.
From these results, we concluded that the cholestyramine reduced the total, VLDL- and LDL-cholesterol, and increased the HDL-cholesterol for the relative short period as many reports. It was also suggested that there are acute effects of cholestyramine on the LDL-cholesterol.

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Myocardial infarcts were frequently seen in the homozygous WHHL rabbits that had severe atherosclerotic lesions at radices of main coronary arteries. Normal control rabbits with normolipidemia at the same age had neither atherosclerosis of main coronary arteries nor myocardial infarcts. However, some control and homozygous WHHL rabbits had intimal thickening of small arteries in the myocardium with tiny focal necroses of myocardium around those affected vessels.
These findings suggest that intimal thickening of small arteries was related to neither a predisposition of WHHL rabbits nor hyperlipidemia, and that the myocardial infarcts peculiar to the WHHL rabbits were mainly caused by hypercholesterolemia like familial hypercholesterolemia in man. Thus, the WHHL rabbit may be a useful model of human myocardial infarction in general as well as a model of familial hypercholesterolemia.

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Physical activity and serum lipids, lipoproteins and apolipoproteins were examined in 12 healthy men. Physical activity was calculated based on the relative metabolic rate of individual activities and expressed as total energy expenditure (kcal/kg/day). Physical activity had a tendency to correlate with HDL-C (r=0.536, p<0.1). Physical activity was significantly correlated with apo C-II (r=-0.646, p<0.05). Also, physical activity was significantly correlated with apo A-I/B ratio (r=0.660, p<0.05). No significant correlations were observed between physical activity and TC, LDL-C, TG, apo A-I, apo A-II, apo B, apo C-III, apo E.

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Phosphatases in rat thoracic aorta and cultured smooth muscle cells derived from the aorta have been investigated. In the present study, changes in the phosphatase activity of cultured smooth muscle cells with the passage and with the growth and the effect of change of medium on acid phosphatase activity were investigated.
Acid phosphatase activities of rat thoracic aorta and cultured smooth muscle cells in early passages (4-30) increased at pH 5.5, while those of cells in late passages (more than 100) increased at pH 3.5. This suggests that there may be two types of acid phosphatase. Although alkaline phosphatase activity of the intact aorta increased at pH 10.5, that of cultured cells was significantly weak at any alkaline pH.
Acid phosphatase activity expressed on the basis of protein content increased with the growth, while that expressed on the basis of cell number remained nearly constant.
Acid phosphatase activities of cells cultured for 1-2 days after change of medium were lower than those of cells cultured for the same period without change of medium. Of components present in the medium, serum was most effective for this reduction of enzyme activity.

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Glucocorticoid excess is known to evoke plasma lipid elevation in both men and animals, however, the effect on lipid metabolism in patients with nephrotic syndrome (NS) is still unclear. Present study deals with the effect of prednisolone, the most widely used oral glucocorticoid preparation, in two nephrotic groups of steroid resistant NS (SRNS) and steroid sensitive NS (SSNS), and changes of serum lipids, lipoproteins and apolipoproteins were investigated.
Total cholesterol (TC) was significantly increased after prednisolone treatment (80-125mg, alternate day) among the patients with SRNS whose urinary protein unchanged, while TC was remarkably decreased after the drug treatment (30-60mg, every day) in the patient with SSNS whose urinary protein rapidly disappeared. These changes well related to serum total proteins or albumin concentration. A prospective study was then carried out in 7 patients with SRNS, and a significant rise in high density lipoprotein (HDL) cholesterol and its major apolipoprotein (apo) A-I were observed during 2 months therapy by prednisolone. Apo C-II, apo C-III, apo E but apo B were significantly increased after one month of prednisolone. Triglyceride did not change. Increased HDL-C levels was associated with the appearance of smaller HDL particle and the reduction of larger HDL particle in the plasma as assessed by gradient gel electrophoresis. These data indicates that prednisolone accerelates the direct synthesis of HDL and its major protein apo A-I without affecting triglyceride or apo B levels, which suggests an antiatherogenic effect of prednisolone in SRNS.

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The morphological changes of coronary and middle cerebral arteries in the cases of cerebral apoplexy and myocardial infarction were analyzed by morphometric techniques at light microscopic levels.
The ratio of circular extension length per thickness of media (MED) was increased with intimal thickness in coronary artery.
The increased MED accompanied with the increasing of medial smooth muscle cells in coronary arteries. The mesenchymal components composed of elastic and collagen fibers was differenced in the ratio between cerebral and coronary arteries.
The characteristics of atherosclerosis is circumference thickening instead of concentric thickening in coronary arteries compared with cerebral artery.
The atherosclerosis shows organ specificity in cerebral apoplexia and myocardial infarction and it suggests the difference in the angiospastic potentiality of each arteries.

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In this study, phospholipid composition as well as lipid composition of VLDL, LDL and HDL in hypertriglyceridemia and hypercholesterolemia were investigated. As hypercholesterolemic subjects, familial hypercholesterolemia were studied. Lipid composition and phospholipid composition were determined by thin layer chromatography. All hyperlipoproteinemic subjects were classified into type IIa, IIb and IV. In the type ha hyperlipoproteinemia, VLDL has more amounts of cholesterol esters and HDL contains more amounts of free cholesterol than those in the control subjects. In the type IIb hyperlipoproteinemia, VLDL is enriched in free cholesterol. In the type IV hyperlipoproteinemia, LDL and HDL are characterized by an elevation of triglyceride. As for phospholipid, in the type IV, LDL is enriched in phosphatidylcholine (PC) and poor in sphyngomyelin (SM) although other lipoproteins are almost the same composition as those in the control subjects. In the type IIa hypercholesterolemia, compositional change of increment of SM and depletion of PC were observed only in HDL. There was not any change in the type IIb lipoproteins.
Furthermore, the data suggest that LDL particle is smaller in type IIa, IIb and IV than normal LDL particle. And HDL particle in familial hypercholesterolemia seems to be less fluid.

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Lipids metabolism during prolonged fasting (10-days complete fasting) has been studied in 23 psychosomatic patients (9 male and 14 female, average 29.2 y. o.), who had no metabolic disease.
During the fasting period, serum F.F.A. and Cholesterol levels significantly elevated (p<0.001).
In the lipoprotein fraction, LDL-cholesterol and LDL-triglyceride (d: 1.006-1.063) significantly elevated by fasting (p<0.001), but VLDL-triglyceri de (d;<1.006) decreased (p<0.05).
The increase of LDL reflected the increase of LDL₂-fraction (d; 1.019-1.063), and this was related to thyroid hormone levels. T₃ levels decreased during prolonged fasting (p<0.01).
It was considered that increase of LDL was related to the decrease of LDL-receptor activity which was dependent on T₃-levels.

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We compared the effects of an anti-hypertensive drug, guanfacine, as α₂-adrenoceptor agonist and an anti-depressant, mianserin, as α₂-antagonist on platelet aggregation in in vitro and in vivo studies. In the in vitro study in 6 healthy male subjects aged 24 to 37, both agents suppressed platelet aggregation induced by epinephrine (10μM) in a dose-dependent manner. The percentages of aggregation at 5 minutes with the α₂-agonist were significantly lower at the concentrations of 10^-5M (mean±SEM=19.8±4.6%, p<0.05) and 10^-4M (6.7±1.2, p<0.005) than those of the saline controls (52.8±11.3) as well as the α₂-antagonist. However, the aggregation induced by ADP (10μM) or collagen (10μg/ml) was not affected by either drug. Since synthetic α₂-agonists such as clonidine are considered to be partial agonists for platelet aggregation induced by sub-threshold concentrations of ADP and thrombin etc., we compared the effects of guanfacine (10^-6 to 10^-4M) on the aggregation induced by ADP (0.5 to 10μM) in two of the subjects. The results demonstrated that the α₂-agonist increased aggregation induced by ADP (0.5μM) in a dose-dependent manner (1st degree aggregation, 12% at 10^-4M) compared with the control level (4%), whereas it did not affect aggregation induced by 2μM (1st degree, 29%) or 10μM (2nd degree, 71%) of ADP. In the in vivo study in 6 patients with essential hypertension aged 46 to 69, platelet aggregation induced by epinephrine (2μM) and collagen (2μg/ml) were significantly suppressed by guanfacine treatment at 3 months compared with the 0 month controls, whereas that induced by ADP (2 and 10μM) was not affected by the drug. The blood pressure was also significantly lowered at 1 and 3 months. These results suggest that an α₂-agonist, guanfacine, may have no noteworthy partial agonistic effect clinically, and may act as if it is an α₂-antagonist at least against platelets. This hypothesis may be supported by the suppression of collagen-induced platelet aggregation in vivo after treatment with it, which was not seen in the in vitro study. The association of such anti-platelet action in addition to the original anti-hypertensive effect of guanfacine may be clinically beneficial for the prevention of cardiovascular accidents, although the precise mechanisms remain to be clarified.

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We investigated the effect of an anti-arteriosclerotic agent Elastase (Elaszym®) on coronary arteriosclerosis in rabbits by histochemical observation and quantitative analysis of smooth muscle cell (SMC), elastin (EL), collagen (CL), acid mucopolysaccharides (AMPS) and glycoprotein (GP) in coronary media. The subjects were male 38 month-old Japanese White Rabbits. Of the 23 rabbits studied, 8 were healthy (H group), 9 had coronary arteriosclerosis (S group), and 6 had coronary arteriosclerosis and were administered with the Elaszym (A group). Arteriosclerotic rabbits were prepared by the combination of 3 method, the hypoxic method in which N₂ gas inhalation was given to the rabbits daily for 2 consecutive weeks, the injury method in which intramuscular administration of norepinephrine was given for 22 weeks, and the preparation method of coronary intimal lesion in which oral administration of cholesterol (0.5g/day) was given for 22 weeks. The rabbits in A group were given Elastase at the dose of 6 cap/day (10.800 EU) once a day for 22 consecutive weeks starting simultaneously with the load of above mentioned preparation. On completion of the treatment, all the rabbits were terminated and histologic specimen was picked up from the left coronary tissue with myocardium for subsequent observation and quantitative analysis of above mentioned 5 components in proximal coronary artery by microspectrophotometry. Comparisons were made of histologic image and quantity of each component among these 3 groups, furthermore, each group was comprehensively evaluated for its characteristics by the principal component analysis of change in 5 components.
S group demonstrated decrease in SMC because of hypertrophy, swelling, atrophy, necrosis and extinction. Uniform distribution of EL and CL was observed due to swelling decomposition and local abnormal hyperplasia. More active hyperplasia was recognized in AMPS and GP than in the case of EL or CL as a repair mechanism of damage. There appeared stratified delamination of elastic fibers from internal elastic membrane and it caused hypertrophy of intima as well as diminution on plasmotomy of elastic membrane. In A group, every kind of impairment as observed in S group was suppressed and the basic architecture of coronary artery was well maintained. The values of SMC, EL, CL, AMPS, GP were 65.4, 9.6, 25.7, 14.4, 22.8%E respectively in H group, 46.7, 12.2, 35.6, 20.2, 31.6%E respectively in S group, and 62.6, 11.3, 29.1, 11.8, 26.2%E respectively in A group. In S group, significant decrease was observed in SMC value with significant increase in EL, CL, AMPS and GP compared with those in H group. In A group, these changes were significantly suppressed compared with those in S group. Individual scores in the 1st and 2nd components were plotted in the two-dimensional coodinates for each case. The dots of H group were distributed in the left narrow range while the dots of S group were distributed in the right wide range of the coodinates. Thus these 2 groups showed quite different architectural characteristics of artery. However, the distribution of A group was observed in the left narrow range similarly to that of H group. Therefore, it can be considered that the rabbits in A group have architectural characteristics closely akin to those in H group. These findings suggests an inhibitory effect of Elaszym on development of coronary arteriosclerosis.

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Using 52 healthy human controls, the composition of fatty acid was determined serum phosphatidyl choline (PC), lysophosphatidyl choline (lyso PC) and cholesterol esters (CE) in patients with ischemic heart disease (IHD).
The activity of lecithin cholesterol acyltransferase (LCAT), which is believed to be related to the transfer of fatty acid in the lipid fraction, was determined. As well, the activity of lysolecithin acyltransferase (LAT), which transfers the acyl group into lyso PC to synthesize PC, was also determined. These studies were conducted to evaluate the enzymes' influence on the changes in composition of the fatty acids in arteriosclerotic diseases.
When compared to the control group, the IHD group had higher levels of palmitic acid and stearic acid in PC and CE, and lower levels of linoleic acid in PC and CE. Whereas, in the case of lyso PC, the levels of palmitic acid and stearic acid were lower and the level of linoleic acid was higher in the IHD group.
The activity of LAT was significantly higher in the IHD group. PC had a positive relationship to the level of palmitic acid, and lyso PC had a negative relationship. The synthesis of PC with lyso PC as the substrate was confirmed by these studies. It is believed that the elevation of LAT activity can accerelate the synthesis of PC in a high concentration by means of this mechanism.
These results suggest that the elevation of LAT activity in cases with IHD may influence changes in composition of fatty acids in PC, lyso PC and CE.

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