The author has previously shown that continuous intimal injury induced in the rabbit aorta by insertion of polyethylene tubing causes atherosclerotic lesions resembling those seen in man.
There were experimentally studied the initial, morphologic events of the aortic intima that preceded atherosclerotic lesions. Endothelial damage was induced in the aortas of the male New Zealand White rabbits by insertion of a poly-ethylene tubing into the aorta from the femoral artery.
Intact endothelialized arterial intima in vivo did not react with circulating platelets and did not induce thrombosis. Denudation of the endothelial cells and direct exposure of subendothelial materials mainly of microfibrils were essential to platelet adhesion and initiation of mural thrombosis in vivo. The most denuded areas were graudlly covered with neoendothelial cells extended only from the surrounding normally endothelialized region and proliferation of smooth muscle cells simultaneously occurred as a repair process. The mural white thrombi were occasionally formed on the denuded areas and subsequently organized by proliferation of smooth muscle cells derived from the underlying media.
These two processes resulted in more or less diffuse but a little intimal thickening or in focal, raised intimal thickening which are considered to be “preatheromatous” lesion. If the endothelial damage repeatedly occurs, the lesion may reach the pronounced intimal thickening that further develops the atherosclerotic lesions.
Thus, this study supports the concept that the endothelial damage is a major prerequisite for intimal thickening.
We must learn how the endothelial damage occurs in vivo under a physiological or subphy-siological condition.

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There was not much doubt that cells grown out from the rabbit aortic wall after peeling off the adventitia and outer part of the media were smooth muscle cells in vitro. Growth factors for the arterial smooth muscle cells prepared from platelets and hyperlipidemic sera stimulated proliferation of the cells, more effective in the latter.
Hyperlipidemic low-density lipoprotein increased uptake of radioactive proline into the muscle cells, but crude platelet growth factors did not show any influence on this phenomenon.
The platelet growth factors appeared to enhance internalization of cholesterol into the smooth muscle cells.
Results of these experiments could suggest that some kinds of growth factors for the arterial smooth muscle cell not only increased proliferation, but also altered metabolism of the cells to facilitate development of atherosclerosis.

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A total of 215 autopsied hearts with myocardial infarction was pathologically studied. Coronary arteries were examined by multiple cross sections at each 0.3cm interval. Grade of the coronary narrowing was estimated by scores: 1 for minimal, 2 for 25%, 3 for 50%, 4 for 75% stenosis and 5 for complete occlusion. Entire epicardial course of the coronary main branches including left main trunk (LS), anterior descending branch (Ad), circumflex branch (C) and right coronary artery (RCA), was divided into 17 segments with equal length approximately 1.5cm long, and stenotic score was expressed by the maximal stenosis at each segment. Coronary thrombosis was diagnosed mainly using a magnifying glass and divided in fresh or old thrombosis either its organizing process was under progression or already finished, and a microscopic study was added whenever necessary. Thrombosis in intramyocardial small vessels was microscopically studied in and around the infarcted area. The myocardial infarction was divided into massive necrosis (M) type, scattered necrosis (S) type and extensive subendocardial infarction.
The overall incidence of coronary thrombosis was 53% and the incidence was high in the M type infarction to 70% in male (especially highest to 84% at the seventh decade) and to 63% in female. The thrombosis appeared only 43% even in the M type infarction during initial 24 hours from the attack and increased thereafter up to 80%. The anterior infarction fairly matched thrombosis in Ad, but the lateral or posterior infarction did not show so intimate relation to thrombosis in C or RCA respectively. S type and subendocardial infarction seemed to be not essentially related to coronary thrombosis.
Fourty-six fresh thrombi detected in the materials, had a trend to occur at moderately narrowed atherosclerotic lesion. In male, average stenotic score at the proximal segment to thrombosis was 0 for LS, 3.6 for Ad, 3.8 for C and 2.0 for RCA. In female, it was 1.5 for Ad, 3.2 for C and 3.5 for RCA, showing a quite difference to male. One hundred and fourteen old thrombi made 17% increase of stenotic score at the proximal segment and 27% increase at the distal segment to thrombosis, after incorporation to the slcerotic lesion. The old thombi showed less marked branch difference in stenotic score than the fresh ones. Histological study on thrombosis revealed a possibility of dissolution of organizing thrombi when formed on mildly narrowed lesion.
Thrombosis or abnormal intimal proliferation in the intramyocardial small arteries appeared by approximately 30% of fresh or old infarction cases respectively, and venous thrombosis was recognized in 12% of fresh cases only. The coronary thrombosis in major branches seemed to be primarily related to typical myocardial infarction and those in intramyocardial vessels would be secondarily formed after myocardial circulatory failure started.

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The purpose of this study is to reveal t he relationships of several risk factors such as blood pressure, HDL-and LDL-cholesterol levels, blood hematocrit values, blood viscosity and antithrombin III values to the non-embolic athero-thrombotic brain infarctions (ABI) in the aged.
The materials consisted of 119 cases with ABI, 68 males and 51 females, with the average age of 70.8 years. Patients diagnosed as cerebral embolism were excluded. Angiographic examinations were performed in all cases to determine the site of occlusion and to estimate the degree of atherosclerotic changes. The results were as follows:
1) Arterial occlusion due to thrombosis was found in 30% of ABI patients, in which 13.4% were found in extracranial arteries and 16.7% in intracranial arteries. In the remaining 70% of ABI cases occlusions were not found.
2) Atherosclerotic changes were more frequent and severe in intracranial arteries than in extracranial arteries. The degree of atherosclerosis was more severe in hypertensives than in normotensives. But there was no such difference in the degree of atherosclerosis between cases with diabetes mellitus and cases without.
3) Atherosclerotic ulcers at carotid bifurcations were found in 18.5% of the cases. However, there was no difference in the incidence of patients who has transient ischemic attacks before complete stroke between cases with atherosclerotic ulcers in the carotid bifurcations and cases without.
4) There was no significant difference in high density lipoprotein cholesterol levels between ABI cases and control subjects in both sexes of the same age groups. However, HDL-cholesterol levels were significantly lower in cases with occlusions in extracranial arteries than in cases without. In female patients LDL-cholesterol levels were significantly higher and therefore lower HDL/LDL cholesterol ratios compared to controls. But in male patients such tendency was not found.
5) The average hematocrit value was signicantly higher in ABI cases; in 26% of ABI cases blood viscosity was higher than the upper limit of control group.
6) The average antithrombin III value was significantly lower in cases with ABI than in controls. However, there was no difference in antithrombin III values between cases with arterial occlusion and cases without.
In conclusion, arterial occlusions were found in relatively small proportion of cases with ABI in the aged, and atherosclerotic changes were more frequent and severe in intracranial arteries than in extracranial arteries. High blood viscosity and low antithrombin III were related to ABI as a whole, but low HDL cholesterol levels had relation only to occlusions of extracranial arteries.

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The mechanisms of development of thrombosis or intravascular coagulation were discussed with respect to blood coagulation and fibrinolysis.
The significance of antithrombin III and α₂-plasmin inhibitor was emphasized. Also hereditary nonfunctioning abnormal plasminogen found in a patient with recurrent thrombosis was discussed in view of the possible cause of idiopathic venous thrombosis.

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The clinical significance of platelet function tests in arteriosclerotic patients is not yet defined although the important role of platelets in pathogenesis of arteriosclerosis and its complication have been established. We had encountered a 74-year old male suffered from acute cerebral thrombosis and observed enhancement in his platelet function including release reaction and aggregation immediately after the onset of the disease. To inquire into the mechanism of his interesting results, platelet functions in arteriosclerotic patients are analyzed after exercise test as an analogous state of acute thrombosis and the results were compared to normal healthy controls.
Ten healthy males (H) and 21 arteriosclerotic male patients (A) including 13 with ischemic heart disease and 8 with ischemic cerebrovascular disease were exercised on a treadmill using Balke protocol. Blood samples were taken before (C) and immediately after the exercise (E). Platelet functions were studied by measuring maximum intensity of platelet aggregation, platelet sensitivity to ADP-aggregation, plasma β-thromboglobulin (β-TG), plasma platelet factor 4 (PF-4), plasma thromboxane B₂ (Tx-B₂) and plasma von Will-brand factor (vWF).
Maximum intensity of platelet aggregation by collagen 2μg/ml in AC (60.9±5.4%) was significantly enhanced compared to HC (48.1±8.9%). Plasma Tx-B₂ in AC (311±17pg/ml) was significantly higher than in HC (254±17). There were, however, no significant changes after the exercise. β-TG levels were significantly elevated after the exercise in both groups; HC: 31.1±3.7, HE: 41.3±5.1, AC: 43.6±6.7, AE: 79.1±11.8ng/ml. But the increment in arteriosclerotic patients was significantly higher comparing to controls. Plasma PF-4 levels were also elevated after the exercise in both groups, but not significant. There was no significant difference between HC and AC in platelet sensitivity to ADP-aggregation and plasma vWF level. But their significant enhancement was seen after the exercise in arteriosclerotic patients. As a summary, in arteriosclerotic patients, the intensity of platelet aggregation and Tx-B₂ were elevated before the exercise, and platelet sensitivity to ADP-aggregation, β-TG and vWF were significantly increased after the exercise.
These results suggest that enhanced platelet aggregability and increased Tx-B₂ were considered to reflect a tendency of platelets to induce aggregation and release reaction, and that the increase in platelet sensitivity to aggregation and platelet release reaction were considered to show a trigger state to induce next thrombotic complication in arteriosclerotic patients.

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Platelet aggregation was inhibited in the rabbits administered aspirin or ticlopidine. Ingestion of more than 50mg of aspirin or 100mg of ticlopidine significantly reduced the incidence of total occulusion in the femoral artery with experimentally induced stenosis following injection with ellegic acid, although no effects were observed in stasis thrombus formation in the jugular vein of rabbits. Daily i.v. injection with 33mg of aspirin/kg of body weight or oral ingestion of more than 100mg of aspirin for 3 days completely inhibited PG I₂ formation in the aorta of the experimental rabbits. Significant formation of PG I₂ was observed in the aorta of the rabbits i.v. injected with 6.6mg/kg or orally ingested with 50mg of aspirin, while collagen (20μg/ml)-induced platelet aggregation was almost completely inhibited.
On the basis of these results, the basic problems relating to antithrombotic therapy with drugs which inhibit platelet function have been discussed.

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Our previous epidemiological study in the farming village (Tanushimaru) proved the importance of hypertension and hypoalbuminemia as risk factors for stroke.
The purpose of this report is to identify the features of stroke in the fishing village (Ushibuka) where hypoalbuminemia is unusual due to high intake of fish protein.
Cohort of the fishing village was consisted of stroke free 314 males (aged 50-79) and age, systolic blood pressure, electrocardiogram, serum cholesterol, serum triglyceride, serum α-lipoprotein fraction, serum albumin, serum uric acid, drinking habits, smoking habits and body mass index of each individual were checked at the systematic re-examination in 1970. Statistical data were computed by multivariate analysis.
Thirty males had stroke during 8-year of following up period (1970-1978).
The mean value of age, systolic blood pressure and serum uric acid level were significantly higher in the stroke group compared with that in the non-stroke group, while serum cholesterol, triglyceride, α-lipoprotein fraction and albumin level were not significant.
High level of serum uric acid was correlated with high incidence of stroke.
According to stepwise discriminant analysis using above mentioned 11 variables, electrocardiographic abnormalities (Minnesota Code 4-1, 2, 3 7-1, 2 8-3) could discriminate 66.6% of strokes and when systolic blood pressure, serum uric acid, serum α-lipoprotein fraction and age were added in order, resultant discriminant rates were 71.6%, 73.9%, 74.2% and 74.5% respectively.
Standardized coefficients of linear discriminant functions were significant only in the following variables of electrocardiographic abnormalities, systolic blood pressure and serum uric acid level.
As well as electrocardiographic abnormalities and systolic blood pressure, high level of serum uric acid was noted to be an important risk factor of stroke in the fishing village (Ushibuka) where high intake of fish protein is common.

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Among 16, 759 persons, 107 persons with hyperlipidemis and with a total cholesterol level over 300mg/100ml were found. The prevalence rate of hyperlipidemia was found to be 0.64 per cent. Among them, 72 persons received reexamination; and by the electrocardiographic finding they were divided into two groups, one group with and the other without ischemic change. The results are as follows:
1) In the group with ischemic change; the average age, the degree of obesity, the mean systolic blood pressure and the mean cardiothoracic ratio were found to be larger than those of the group without ischemic change.
2) In the group with ischemic change; the mean fasting blood sugar, triglyceride and uric acid were found to be elevated compared with the group without ischemic change. The mean HDL-cholesterol level in the former group was a little lower than that of the latter group. It is presumed that the above mentioned differences of clinical findings will act additively on the development of ischemic heart desease.

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The term cardiocerebral apoplexy was advocated by Okinaka and later defined as a syndrome by Fujii et al.
This syndrome begins with a symptome of cerebral apolexy and has sometimes macroscopic encephalomalacia combined with evidence of acute myocardial infarction.
For the purpose of investigation of this syndrom, the cerebrum in 41 unselected consecutive cases of myocardial infarction were pathologically studied and following results were obteined.
1) Seventeen cases had macroscopic encephalomalacia without bleeding (39%).
The remaining cases had no macroscopic changes (61%).
2) Three cases of the former change group had vascular thrombi around the point 1cm distal to the origin of middle cerebral arteries.
3) The rest of cases with no macroscopic cerebral abnormalities showed variable non-specific microscopic changes which were not particularly related to acute myocardial infarction.
4) In comparison with the macroscopic cerebral change group to non change group, arterial atherosclerosis was more severe in the former group.
5) Three cases of clinical cardiocerebral apoplexy were found in macroscopic change group.
6) Concerning to the pathogenesis, cardiocerebral apoplexy is thought to be the results of severe ischemia of systemic organs including heart and brain.

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A pathological study on the cerebrovascular lesions was performed on 59 diabetic human autopsy cases and 292 non-diabetic cases (controls).
At first, the cerebrovascular lesions were observed macroscopically on all cases, and the correlation to ages was investigated.
Secondary, microscopical softening or subsoftening changes were observed on specimens obtained from bilateral ganglionic regions of 27 diabetic cases. Each findings was divided into five grades, and it's correlation to blood pressure, diabetic glomerular lesions, etc. were investigated.
Following results were obtained.
1. The cerebral softening was more frequent in diabetic cases than in controls, but the cerebral hemorrhage was more frequent in controls than in diabetic cases, as far as in macroscopical observation.
2. Microscopically, many softening and subsoftening changes were found in the basal ganglionic sections of the many diabetic cases that have revealed no obvious macroscopical changes. The severe changes were seen more frequent in hypertensive cases than in normotensive cases.

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The common carotid arteries of rabbits previously fed a normal or an atherogenic (normal diet supplemented with 1% cholesterol and 5% lard) diet were injured by local freezing for one minute with liquid nitrogen. After injurey, animals were divided in three groups. Group Ia was fed the normal diet for 3 to 4 weeks before injury and then given also the normal diet for up to 8 weeks after injury. Group Ib and II were pretreated with the atherogenic diet for 3 to 4 weeks before freezing. After injury, group Ib was given the atherogenic diet through the experimental period up to 14 weeks, and group II was fed the atherogenic diet for 2, 4 and 8 weeks and then given the normal diet for the next 3 or 6 weeks. The arterial lesions were studied by light and electron microscopy, and intimal thickening of the central part of the injured segments was measured with a planimeter.
In group Ia, only slight cellurofibrous intimal thickening was observed even 8 weeks after injury. In group Ib, severe intimal thickening consisted mainly of foam cells was formed in animals which were killed 4 or 8 weeks after injury. In group II, after cessation of the atherogenic diet, foam cells and extracellular lipids decreased and smooth muscle cells, collagen and elastic fibers and ground substance increased in the intima, resulting in more marked intimal thickening as compared with that of group Ib.

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It is well known that an aortic wall contains acid mucapolysaccarides (AMPS) and their components change with the progression of arteriosclerosis. To observe their changes in arteriosclerosis, the thoratic aorta from 10 normal rabbits and 10 rabbits, feeded by 1% cholesterol diet for 8 weeks, were examined with Ruthenium red stain which had been reported to stain AMPS specifically. We had the following result from the electron microscopic observation of endotherial cell and subendotherial space in the materials.
The surface of the endotherial cell and the intercellular junction of the thoratic aorta in normal rabbits were stained better than that in cholesterol feeded rabbits. In cholesterol feeded rabbits, they were stained poor and rough. The ruthenium red positive substances were observed in the subendotherial space of normal rabbits aorta. They connected each other making a network structure and touched to the transverse stripe of collagen fibers in the subendotherial space.
From the observations stated above, the AMPS covered over endotherial cell surface may protect the invasion of plasma into the subendotherial space.
Rough ruthernium red stain of the endotherial cell surface may suggest change of components of AMPS.
The invasion of plasma components into the subendotherial space produced the intimal edema and resulted in the disappearance of the network structure in subendotherial space of cholesterol feeded rabbits aorta.

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The difference between diabetics and nondiabetics in the pattern of major coronary circulation, distal to the complete obstruction through nonvisualized collaterals are seen on the cine-angiography. Distal circulation to the complete or near-complete obstruction via nonvisualized collaterals shows approximately one second delay filling, although that filling of nondiabetics has immediate. In order to explain this difference, major coronary arteries and their small intramural branches were histologically examined in each 9 cases of diabetics and nondiabetics. The degree of major coronary stenosis were macroscopically determined with every 5mm length.
The several samples of the muscles containing obstructed and nonobstructed arteries were obtained to see the state of intramural small arteries. Tissue were stained HE, EVG, Azan and PAS. The histological findings were classified into five lesions according to the descriptions of Blumenthal and Saphier; 1) Hemodynamic lesions: Fibrous or fibroelastic intimal thickening or plaque formation. 2) Atheromatous lesions: Atheromatous thickening with lipid in intima or in plaque. Atheromatous hyalinized thickened intima. 3) Thrombotic lesions: Mass of fibrin or enmeshing erythrocytes attached to the endothelial surface. 4) Inflamatory lesions: Perivascular cellular infiltration, perivascular adventitial fibrosis, intimal fibrosis and hyalinization and fibrous changes in the media. 5) Proliferative lesions: Endothelial proliferation forming mounds, papillary projection and bridges. Intramural small arteries were divided into three group, 20-60 microns (small), 70-150 microns (medium) and 160-500 microns (large) according to their calibers.
The degree of lesions were expressed as the percentage, the number of abnormal vessels in the total number of examined ones. These were as the following:
Diabetic group Nondiabetic group
small 44.8% 32.3%
medium 61.3% 33.8%
large 62.1% 38.9%
total 54.2% 34.0%
In the cases of complete or near-complete obstruction, distal filling from the proximal portion as bridgning collaterals must be due to anastomoses via intramural small arteries. Although these small vessels are not visualized angiographically, the filling delay to the distal segment beyond the obstruction in diabetics are believed due to small vessel disease, being seen more frequently in diabetic patients. These abnormalities would affect the prognosis of the diabetic patient to be worse than nondiabetics with the same degree of major coronary artery obstruction.

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The acquirement of nutrition of the coronary arterial wall seems to be a very important subject in studying on the pathogenesis of atherosclerosis. One of the most impressive morphological characteristic of coronary atherosclerosis is a localized eccentric intimal thickening, which may be caused by many factors. This characteristic may not be explained only from stand point of the serum lipid insudation theory. Local circulatory disturbances within the arterial wall may be one of the factors that cause such localized and eccentric lesions of atherosclerosis.
To study this subject, about 100 segments of coronary arteries and veins obtained from 15 autopsy cases without significant heart diseases, aged 36 to 78 years were used. The arteries and veins were injected with silicone rubber from the coronary sinus and orifices of the coronary arteries, and then were cleared with solution of alcohol-metyl salicylate. They were observed to analyse a morphology of the vasorum in the coronary arteries on multiple sections under a dissection microscope.
The obtained results were as follows:
1. Three types of arterial vasculature were distinguished, as almost same results as those that had been previously reported by many researchers.
2. It was apparently recognized that venous channels existed within the media of the coronary arteries and were drained out toward the adventitia.
3. Atherosclerotic plaques of coronary arteries showed localized proliferation of intramural vasculature in the intima and also in media.
These results were indicative that the disturbance of intramural circulation in the arterial wall might be one of factors in developing such characteristic of coronary atherosclerosis.

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Coronary arteries were obtained from 198 cases of accidental sudden death. The intimal surface of both left and right branchs was examined to divide into 3 portions as follows: I, normal; II, slight change (lipid deposition, smoothly surfaced fibrous plaques); III, moderate plus severe change (plaques, necrosis and calcification). The extent of coronary atherosclerosis was measured by the wet weight ratio of sclerotic portion (wet weight ratio of II and III to total wet weight).
The correlations among 4 factors (age, right, left and total sclerotic weight ratios) were calculated by using a computer, HITAC 8700/8800. The coeffecient of correlation between right and left sclerotic weight ratios was 0.6801 (p<0.01). This was lower than the others. The coefficient of correlation between right and total and between left and total were 0.8901 (p<0.01) and 0.9171 (p<0.01), respectively. Those of age to right sclerotic weight ratio, age to left sclerotic weight ratio and age to total sclerotic weight ratio were 0.3862, 0.4024 and 0.4217, respectively.
In the coronary artery, the atherosclerosis seemed to advance in a different manner between right left branchs. Closed relation, however, was obtained between coronary arteriosclerosis and aging under the present condition.

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The pathological changes of the conduction system which involve in aging process has attract much attention of the cardiologists as it may lead to unexpected clinical death, however, scanty morphological observation of it has been hitherto documented.
Moreover the interrelationship between the degenerative process of the cells composing the conduction system and extent of the arterioscerosis of the distributing vessels should awaits further confirmation.
In this viewpoint, the authors have conducted an investigation of the histo-pathologic pattern of the various portion of the conduction system (Sinus node, A-V node, bundle branches in 32 cases varying in various age group which are devoid of any discernible heart diseases.
Observation:
The decrease of the cell population in the sinus node, A-V node and His bundle is observed in age group of beyond fifty without exception.
The pathological changes involving the both bundle branches remained to be a lesser extent, however, gradual involutional changes are discernible beyond sixty.
The authors failed to confirm the arteriosclerotic changes of the small arteries, particularly of sinus node artery which give supply to the sinus node and other arteries giving supply to the region beneath the A-V node on aging.
In some cases which are involved in relatively remarkable degeneration and loss of cells of the conduction system, rather intensive lipid infiltration in the medial layer, however, the extent of the myocardial fibrosis remained to be a lesser extent which are obviously substantiated with the ultrastructural observation.
The facts may not be justifiable as the reflect of ischemic process and some abnormalities of the intermediate metabolism involving the lipid and associated substances should be taken into the consideration.
In the group which showed arteriosclerosis and loss of the cells revealed remarkable fibrosis while the lipid infiltration remained to be minimal range.
The ultrastructural observation revealed disintegration of the myocardial fibrils, accumulation of lipid, swelling of the endothelial cells of the capillary vessels and fragmentation of the basal lamina.
Koizumi and Yajima has observed the scerotic changes of the small arteries distributing the conduction system in cases of ventricular septal defect and Tetroalgy of Fallot which may suggest a possibility that the circulatory derangement would be very important contributing factor for direct causing of ischemic process.
In this vicinity the authors incline to believe that the less extent of the screlotic changes in aged conduction system could be explained on based that the ischemic changes in this region is hardly taken placed on account for the specific anatomical distributing pattern of the blood supply.
The authors conclusively would like to place an emphasis on a possibility that the sclerotic changes of the small vessels distributing the conduction system is rather hardly recongnizable without concomitant occurence of the micro-circulatory derangement in this particular region.
The patho-physiological aspect of this microcirculatory derangement is fully augmented in this communication in connection with the arteriosclerotic process, involving the cells and vasculature of the conduction system per se.

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In the field of experimental arteriosclerosis, it is a most important problem, how to examine the sclerotic grade of arteries non-invasively, because we desire to know the changing phases of arteriosclerosis induced in animals, and to estimate the regression or the effect of antisclerotic medicine. We already reported invasive aortic Pulse Wave Velosity (PWV) method and showed to be able to estimate the sclerotic grade of aorta by this technic. Now we improved it in some respects to establish non-invasive measurement. (Materials) Materials consisted of 32 rabbits from 28 W-280W. (Method) 1. Procedure of carotid arterial loop. We can not recongnize the pulsation of carotid artery through the skin in rabbit. So we gave two incision on the skin of the frontal neck. Then we exposed carotid artery and made it free from the surrounding tissues. It was coated by the skin to make loop, which length was about 40mm, and which diameter was about 7-10mm. 2. Measurement of blood pressure. We can estimate blood pressure from the changing phases of the waves described continuously as the diameter change of the carotid artery by the displacement transducer attached to the periphery of the cuff placed on the carotid loop. Under the cuff pressure over maximum pressure, waves will not be appeared. If a wave with a notch on the ascending limb will be appeared, it will point out maximum pressure. Next, the notch will be disappeared and wave amplitude will be reached to maximum. This point will show the minimum pressure. 3. Measurement of PWV. Pulse wave transducer were attached to carotid loop and the portion over femoral artery, and a PCG microphone to the precordium. The pulse wave velosity was then calculated from the equation PWV=D/(t+tc), where D was the distance from the upper sternal border to the point measuring femoral pulse wave. 4. normalization of PWV. PWV were dependent on minimum pressure. So we made up nomogram for normalization of PWV by invasive method in 118 rabbits. (Result) 1. Maximum and minimum pressure were estimated clearly with average error under ±2mmHg. Correlation between the first and second trial was 0.98 in maximum pressure, and 0.92 in minimum pressure. 2. In PWV, correlation between the first and the second (the next day) measurement was 0.97. Its average error was within ±0.3m/sec. 3. PWV and its standard deviation obtained were 5.5±0.49 in un der 39W group, 5.8±0.47 in 40-79W, 6.8±0.37 in 80-119W, 7.1±1.17 in 120-159W, 6.8±0.49 in over 160W. 4. PWVs were increased with ageing and its deviation became higher over 120W.

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Clinical evaluation of atherosclerotic changes of the aorta is difficult except using angiography. The present study was intended to estimate extent of atherosclerosis or compliance of the aorta with non-invasive procedures.
To determine compliance of the aorta, the pressure-volume relationship was employed for the study. Up to this time, measurements of aortic pressure and volume have been done using invasive methodes.
In the present study, pressure-volume Lissajow's figure was plotted with computerized X-Y recorder from simultaneously recorded pulswave by miniature semiconductor pressure transducer fixed upon the brachial artery and plethysmogram by trans-thoracic impedance plethysmography.
Experimentally, pressure-volume Lissajow's figures were recorded invasively with the same computer processing from pressure wave by catheter tip pressure transducer introduced into the thoracic aorta and volume curve with mercury straingage binded on the thoracic aorta of dog.
High correlations were observed between pressure waves recorded by the invasive and noninvasive method and also plethysmogram between mercury straingage and trans-thoracic impedance plethysmography.
Changes of two pressure-volume Lissajow's fingures obtained by invasive or non-invasive techniques were closely correlated by hemodynamic alterations induced by propranolol and methoxamine administration.
These findings may support that the non-invasive pressure-volume Lissajow's figure is an indirect manifestation of the pressurevolume relationship of the thoracic aorta.
Non-invasive pressure-volume Lissajow's figures were recorded on 170 subjects of various aged.
Inclination from the origin to top of the pressurevolume Lissajow's figure was supposed to indicate compliance of the aorta.
The inclination of the third decade was 0.30+0.14mlmmHg and of more than 60 years old was 0.14+0.09mlmmHg.
Thus, non-invasive pressure-volume Lissajow's figure is an complehensive indicator of compliance of the aorta.

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Noninvasive estimation of aortic sclerosis has been studied by a pulse wave velocity method which provided a space mean characteristics. However, sclerotic changes of the aorta were not homogeneous so that estimation of aortic sclerosis should be determined in a given segment. The purpose of this study is to estimate the grade of aortic sclerosis of a given segment of the aorta, of its origin just above the Valsalva sinus using an echo technique. The materials consisted of 63 patients with hypertension, 52 patients with ischemic heart diseases and 100 normal subjects as a control. On 31 cases with ischemic heart diseases coronary stenosis was determined by the coronary angiography. The echo of the aorta was obtained from the anterior chest wall with simultaneous blood pressure determination. Elastance or stiffness of the aorta was calculated from the following equation; Elastance=R₀×ΔP/ΔR×1.33×10³dyne/cm². The elastances were also obtained after the handgrip exercise in order to analyze effect of diastolic pressure on the elastance. Results were as follows; 1) The aortic diameters increased with the aging. 2) The elastance increased with increasing the age. 3) The elastance was affected by changes in diastolic pressure. 4) The mean elastance of the normal subjects was between 0.5 and 1.7×10⁶ dyne/cm², whereas those of the hypertensives and the patients with ischemic heart disease were 2.52 and 2.07×10⁶dyne/cm², respectively. 5) The effect of the exercise test on the elastance was seen in all the groups, especially in the patients with ischemic heart diseases. There was no significant correlation between the elastance after exercise and the stenotic grades. This method for detecting aortic sclerosis is one of the useful method in clinical practice.

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Since typical rapid arterial fat deposition was first noted in hypertensive rats (SHR, DOCA-salt or renal hypertensivee rats) within one or two weeks of high-fat-cholesterol (HFC) diet feeding by Yamori in 1974, experimental studies on atherogenesis in rats have made a great progress. Especially, the exploitation of a simple method to detect arterial fat deposits in cerebrovascular system (Barium Contrasted Sudan Staining (BCSS) Method) has enabled us to investigate factors affecting cerebrovascular atherogenesis such as hypertension local hemodynamic derangements and hyperlipidemia. Moreover, the establishment of arteriolipidosis-prone rats (ALR) by the selection of substrains of SHR which showed a greater reactive hypercholesterolemia indicated the involvement of genetic factors in atherogenesis. In order to analyze genetic factors of atherogenesis, we have attempted to isolate genetic factors of arterial fat deposition from hypertension by separating the colony of normotensive rats which are prone to develop cerebrovascular fat deposits within a short period.
Strain difference in arterial fat deposition in normotensive rats
Six strains of normotensive rats, 20 rats of each, were fed on an HFC diet (containing 5% cholesterol, 20% suet and 2% cholic acid) for 1 year from the age of 30 days. After blood pressure and serum cholesterol level were repeatedly checked, the animals were sacrificed to detect fat deposits in cerebral and mesenteric arteries by BCSS method. Fat deposits were noted only in Wistar-Kyoto (WK) rats, of which 5 and 15% developed fat deposits in cerebral and mesenteric arteris, respectively.
Fat deposition in F₂ generation obtained by the cross-breeding between normotensive rats and stroke-prone SHR (SHRSP)
Therefore, the normotensive WK rats which were proven to be a little more sensitive to fat deposition were mated with 3 female SHRSP with blood pressure 180, 190 and 192mmHg, respectively, to obtain F₁ generation from which F₂ generation was further produced, and blood pressure, serum cholesterol levels and arterial fat deposits were checked as mentioned above. Blood pressure and cholesterol levels in average in F₂ generation were 143±3mmHg (M±SE) and 375±36mg/dl, respectively, after the HFC diet feeding for 3 weeks. Fat deposits in mesenteric and cerebral arteries were noted in 15 and 11 rats out of 26 (58 and 42%), respectively. The F₂ rats with cerebrovascular fat deposits showed no difference in blood pressure from those without fat deposits (137±2 vs. 147±2mmHg), but a slightly higher cholesterol level than the latter group (457±60 vs. 304±32mg/dl).
Summary with Discussion
The establishment of ALR which quickly develop hypercholesterolemia (500 and 800mg/dl) within a week of HFC diet feeding indicates that genetic abnormality related to hypercholesterolemia (increased intestinal cholesterol absorption and decreased catabolism) is involved in the proneness to arterial fat deposition, the initial step of atherogenesis. The present experiment has demonstrated that arterial fat deposition develop in F₂ generation without hypertension, indicating that the proneness to arterial fat deposition can be genetically separated from the heredity of hypertension. These normotensive F₂ rats with arteriolipidosis are hopefully continued to be bred until the establishment of the inbred strain of “normotensive atherogenic rats (NAR)”, the proper model for the analyses on the heredity of atherogenesis.

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Endothelial permeability was electron microscopically investigated using horseradish peroxidase (HRP) or ferritin as a tracer in normotensive and hypertensive (Goldblatt type hypertension by bilateral constriction of the renal arteries) rat arteries.
In the coronary arteries, aortae and mesenteric arteries of mornotensive rats, HRP injected intravenously passed through the endothelial cell junctions and was also transported by the pinocytotic vesicles of endothelial cells. But the tracer did not permeate the endothelium of the cerebral arteries because of their complete tight junctions. In the cerebral arteries, however, pinocytotic vesicles seemed to rarely play a role in the transport of proteins.
Fibrinoid degeneration of the hypertensive rat arteries resulted from insudation and deposition of blood plasma proteins, especially fibrin in the intima and media. The blood plasma proteins were considered by the findings with tracers to insudate into the arterial wall through the endothelial cell junctions, pinocytotic vesicles of the cells, opened endothelial cell junctions and rarely through the cytoplasm of the endothelium. Opening of the junctions of endothelial cells seemed to be formed by contraction of filaments of endothelial cells and by invasion of leucocytes between endothelial cells. In the cerebral arteries, increased permeability of the endothelial cells was observed in the arterial segments showing severe medial necrotic changes.

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To investigate the effect of aging on acid mucopolysaccharides (AMPS) in the aorta, AMPS contents were measured in the aorta of Wistar rats and spontaneously hypertensive rats (SHR, Okamoto & Aoki), 7 weeks, 3, 6 and 12 months old.
Total AMPS were slightly increased with age and mono-sulfated and highly-sulfated AMPS were also increased significantly (p<0.05) with age in Wistar rat.
In SHR, total, non-sulfated and mono-sulfated AMPS were more markedly increased with blood pressure elevation than with age.
AMPS contents were decreased with blood pressure fall by the antihypertensive treatment (reserpine and hydralazine).
It is concluded that AMPS contents in the aorta of rats are more affected by blood pressure than aging.

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Elastin content of aortic media of Wistar-Kyoto rat (WKY) and SHRSP were determined histochemically using microspectrophotometric procedure (MSP method). In WKY, elastin content increased until around 150 days after birth, and then it decreased gradually with age. On the other hand, SHRSP at 50 days after birth showed a maximum content and decreased remarkably with age until around 300 days after birth. After that, it became nearly constant. SHRSP died in early stage with stroke showed a predominant lower content of aortic elastin in comparison with SHRSP without stroke, indicating the close relationship between decrease of aortic elastin and severity of hypertension.
The results of current experiment indicate that the MSP method is useful for the histochemical determination of elastin content. Furthermore, the results also indicate the decrease of elasticity in the aorta of SHRSP, suggesting that aortic elastin has the important role for development of hypertension and/or stroke in SHRSP.

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Ultrastructural and biochemical studies on collagen of the human aorta and vena cava were performed concerning with aging and atherosclerosis. Ultrastructurally the collagenous fibrils of the aortic media and vena cava consisted of two distinct groups of fibrils, small and large fibrils. The medial fibrils especially of large fibrils were surprisingly labile to aging compared to the vena cava fibrils. The medial small and large fibrils of the aorta steadily increased in size up to the age of approximately 20 years, and thereafter unchanged throughout the remaining life-span. Of significance was the fact that the diameter of the medial fibrils was always smaller than that of the vena cava fibrils. On the contrary, the diameter of the vena cave fibrils seemed to be unchanged throughout the whole life-span.
The collagenous fibrils in the atherosclerotic intima consisted of two groups of fibrils as seen in the aortic media. However the diameter of the fibrils in the atherosclerotic intima was smaller than that of the medial fibrils, and was unchanged in all age group.
Biochemical studies indicated that there were at least two genetically distinct type of collagen (type I and III) in the aortic media, vena cava and atherosclerotic intima. The vena cava contained 75% type I and 25% type III collagen. The aortic media consisted of approximately 55% type I collagen and 45% type III collagen. On the contrary, atherosclerotic intima contained larger amount of type I collagen (65%) than the aortic media. The type I/III collagen ratio in the aortic media and atherosclerotic intima was no changed in all age group.
The data described here suggest that the collagen synthesized in the atherosclerotic intima differs from that in the aortic media and that atherosclerosis may not depend on aging.

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Although an injection of renal extracts was known to produce fibrinoid necrosis in the arterioles and small arteries of the bilaterally nephrectomized rats, the substances in the renal extracts responsible for producing the lesions had not been purified and isolated. It was also repeatedly confirmed that crude renin could produce vascular lesions. In the present study, effects of the highly purified renin with or without SQ14225 on angionecrosis were investigated.
Hog renin was purified 45000 fold according to the method described by Inagami and Murakami and injected intraperitoneally into the bilaterally nephrectomized rats. Eighteen hours after injection rats were sacrificed and fibrinoid necrosis was examined histologically by PAS staining. Mean blood pressure of the conscious rats was continuously recorded from the cannulated carotid artery.
When 34μg of pure renin were injected intraperitoneally into the bilaterally nephrectomized rats, mean blood pressure elevated up to more than 170mmHg and fibrinoid necrosis was produced. The elevation of blood pressure as well as fibrinoid necrosis was prevented by the oral administration of SQ 14225 one hour prior to the injection of renin.
These results may suggest that an elevation of blood pressure through renin is essential to produce fibrinoid necrosis.

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We have reported that the vascular injurious factors in the kidney are included in microsonal fractions of the renal cortical extract, and these fractions have no pressor effects. In this experiment, for the purpose to demonstrate the presence of non-pressor renal vascular injurious factor in rats in vivo, observations were made about arterioles and small arteries upon performing right nephrectomy and left renal arterial and ureteral ligation and releasing the renal arterial ligation after 2 hours and ureteral ligation after 24 hours
One day after the surgery, angionecrosis was observed in the media of mesenteric and pancreatic arteries.
3-5 days after surgery, angionecrosis developed fibrinoid necrosis and infiltration of inflammatory cells and fibroblast-like cells was seen in the adventitia. 1 week after surgery, panarteritis-like lesions with or without fibrinoid necrosis were seen, and infiltration of lymphocyte and fibroblast-like cells was observed in all vascular layers, and elastic fibers including internal elastic lamina were elongated, fragmanted, and disappeared. 2-8 weeks after surgery, these panarteritis-like lesions with or without fibrinoid necrosis were disappeared, and proliferation of the intimal cells and cellulofibrous thickening of the media were observed. Weigert's stain pointed out the double structure of internal elastic lamina. These vascular changes were similar to arteriosclerotic vascular changes. In all course of this experiment, no rat showed high blood pressor and slight increase of serum B. U. N. was continued, but serum electrolyte and creatinine were within normal.

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To assess the extent and activity of sympathetic innervation within arterial wall with atherosclerosis, morphological, biochemical and pharmacological analysis were undertaken using normal and atherosclerotic mesenteric arteries of the rabbit. Mesenteric artery of the rabbit with atherosclerosis was produced by feeding 1% cholesterol containing diet.
Adrenergic fluorescent fibers were rarely observed in the wall of atherosclerotic mesenteric artery. Chemical determination also revealed significant decrease of norepinephrine content in the mesenteric artery with atherosclerosis. Nicotine is known to induce indirect (neurogenic) contraction of vascular smooth muscle. Contractile response to nicotine in atherosclerotic isolated mesenteric strips was considerably reduced as compared with that in normal preparation. These results led to consideration of the possibility that deficiency of the sympathetic activity in the atherosclerotic mesenteric artery would partly reflect dysfunctions in the hemodynamic aspect of the atherosclerosis.

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Direct immunofluorescent staining with FITC labelled antibodies against smooth muscle actin and myosin was carried out on cultured aortic medial cells and adventitial fibroblasts from the rat thoracic aorta.
Over 99% of the medial cells in primary culture showed an intense fluorescent staining in long straight fibrils scattered throughout the cytoplasm with antibodies against actin and myosin. After second passage, medial cells could be stained with anti-actin but not with anti-myosin antibodies. The contents of actin became less in the stepwise after second passage. Adventitial fibroblasts in both primary and secondary culture showed no actin and myosin.
It is concluded that rat aortic medial cells in primary culture are purely homogenous population of differentiated smooth muscle cells and lose the differentiated phenotype in terms of actin and myosin after second passage.

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Recently many growth substances have been discovered. We tried to extract the crude platelet factor and fibroblast growth factor (F. G. F.) from the bovine platelets and brains respectively to know whether these are effective to enhance the proliferation of the cultured endothelial cells from canine femoral vein. For this purpose, two conditions were prepared; adequate condition and non-adequate condition. In this experiment, we adopted the cell dencities, more than 3800cells/cm² as adequate condition and less than 1300cells/cm² as non-adequate condition.
Prostaglandin F_2α, thrombin, and platelet factor were also compared concerning proliferative effects for the cultured endothelial cells.
Results;
1. Crude platelet factor was contained in peak 3 of the bovine platelet extracts.
2. Thrombin and Prostaglandin F_2α also promoted the proliferation of cultured endothelial cells, but these were not so effective as platelet factor. And mixture of these three substances was 2 times effective as the control containing no growth factors.
3. Crude F. G. F. appeared in peak 3 of the bovine brain tissue samples.
4. When cell density was more than 3800cells/cm², no difference of growth promoting effect could be seen among control, F. G. F., and platelet factor.
5. When cell density was less than 1300cells/cm², F. G. F. and platelet factor indicated multiplying effect for cultured endothelial cells compared with control. F. G. F. showed multiplying effect stronger than platelet factor.

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Vascular replacement reported by Sparks (1972), silicone mandril method, is difficult for practical use because of its poor antithrombogenicity. We have examined this mandril method concerning the effect of various mandrils and meshes on the growth of granulation tissues. Six mandrils, such as glass, silicone-rubber, polyamide, polytetrafluoroethylene, polymethylmethacrylate, and polyethylene, were covered with Nylon or Tetoron meshes, and then implanted subcutaneously into rats. Each granulation tissue grew around the implant after 20 days. We cut it off with the granulation tissue and then removed the mandril leaving a tissue containing mesh. In the case of polymeric mandrils, such as silicone-rubber, polyamide, polytetrafluoroethylene, polymethylmethacrylate, and polyethylene, the luminal surface were covered with collagen fibers. While, in the case of glass mandril, the luminal surface was covered with a cell-lining. On its surface, platelets did not adhere when the tube was infused with blood. Such antithrombogenic tendency was scarcely obtained in the case of the tube grown by silicone mandril method. The lining cells in the case of glass mandril possibly belong to fibroblast in an active state of collagen production. The antithrombogenic tissue obtained by the implantation of the glass mandril would be useful for practical vascular replacement.

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Endothelial and smooth muscle cells were isolated from freshly excised intact thoracic aorta of 6-month-old swine. Cells were grown in 40ml plastic flasks (NUNC) containing 4ml of TCM 199 supplemented with 20% fetal calf serum for endothelial cells or 10% for smooth muscle cells at 37°C in a moist atmosphere of 95%air and 5% CO₂. The cultured media were changed twice a week. Aortic endothelial cells became confluent in 3 to 6 days and retained the characteristic “cobblestone” appearance. Aortic smooth muscle cells grew to confluency within 2 to 4 weeks depending on the initial plating density and formed a characteristic pattern of “hills and valleys”. After confluency, growing cells were subcultured with trypsin (1:5 routinely). All experiments were performed with cells in primary or in passage of tripsirization 1 through 4.
When the cultured cells grew to confluency, cells were washed with cold physiological saline solution several times and then gently scratched from the flask-bottom with a plastic plate. Cell pellets were collected by centrifugation at 250g for 5 to 10 minutes. The number of cells was prepared approximately 1×10⁷ cells per 1ml of physiological saline solution. The cell-riched suspension were immediately freezed at -20°C and melted at room temperature 2 times repeatedly. The regular fibrin-agar plate method was used to estimate fibrinolytic activity from the supernate. The regular fibrin-agar plate contained 0.2% fibrinogen (plasminogen-rich) and 1.4% agar in 0.01M phosphate buffered physiological saline solution with a pH of 7.4; A thrombin solution was added; A 2mm hole was made in the plate prior to use. Five μl of the supernate was dropped on a regular fibrin-agar plate. For control digestion of the fibrin-agar plate, 5μl of solution of 1000units of streptokinase was used. The plates were incubated for 4 hours at 37°C in a moist chamber.
Contrary to our expectations, plasminogen tissue activator from the cultured aortic endothelial cells was not detected, while occasional fibrinolysis was detectable in the third to fifth subcultured cells; Cultured aortic smooth muscle cells had fibrinolytic activity slightly. In this study, successfull results to estimate the fibrinolytic activity from the cultured endothelial cells were not obtained, although some studies of various ration of cultured medium and calf serum, addition of plasminogen solution, and cellular fraction by ultracentrifugation were performed. There may be still unsolved technical problems; The results would be changeable by extraction methods, culture conditions or estimation methods for studies of plasminogen activator.

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Cholesterol ester hydrolysis activities in rat arterial wall homogenates were determined using artificial lipid inclusions and vesicles sonicated with cholesterol ester and phosphatidylcholine as substrates. Artificial inclusions were prepared with cholesteryl oleate, cholesteryl [1-¹⁴C] oleate, free cholesterol, triolein and phospholipids which were the same components and contents as those of lipid inclusions found in atherosclerotic lesions, namely fatty streak inclusion (FSI) and fibrous plaque inclusion (FPI). Incubations were performed at 37°C.
The influence of temperature at which inclusions were prepared on hydrolysis of cholesterol ester in artificial lipid inclusions and vesicles was observed.
Cholesterol ester hydrolysis was not observed using vesicles without phosphatidylcholine and was increased with phosphatidylcholine when the substrates were prepared at 4°C. When the substrates were prepared at 56°C, cholesterol ester was hydrolysed solely and activating effect of phospholipid was less prominent than that at 4°C. Cholesterol ester in artificial lipid inclusions was hydrolysed when the inclusions were prepared at 4°C. These results suggest that the hydrolysis of cholesterol ester in artificial lipid inclusions was regulated by other components of lipid inclusions.
To evaluate the effects of components of lipid inclusions, the lipid inclusions from which some components were omitted were used as substrates. Among free cholesterol, triolein and phospholipids, cholesterol ester hydrolysis activities in FSI and FPI were remarkably decreased when phospholipids were omitted.

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In an attempt to clarify the mechanism of sex-related differences in susceptibility of atherosclerosis, sex-related differences, and fluctuation in lypolytic enzyme activities of rat aorta due to orchiectomy and gonadal hormone treatment were investigated. Sex-related differences in acid cholesteryl ester hydrolase (CEH) activity were slight at 1 month of age but were marked at 2.5 and 6 months. Mature female rats showed significantly higher activity in acid CEH, neutral CEH and lipoprotein lipase (LPL) compared to the age matched male rats. Orchiectomy was performed at weaning and 2 months of age (young and adult castration), and rats were killed at 2.5 or 7 months. Young castration significantly enhanced the acid CEH activity, while adult castration showed only the tendency. LPL activity fluctuated due to castration in a similar way to that of acid CEH. These results of orchiectomy fitted well a hypothesis concerning the sexual differenciation of hepatic metabolism of steroid hormones. Administration of testosterone (100-500μg/kg, s.c. for 2 weeks to months) to female rats markedly decreased acid CEH activity, while administration of 17β-estradiol (100-500μg/kg, s. c. for 2 weeks to 5 months) to male rats only tended to increase the activity. These results indicate 1) that the observed sex-related differences in aortic acid CEH activity may explain at least partly sex-related differences in atherosclerosis, 2) that testosterone rather than estradiol exerted a greater effect on arterial acid CEH activity. A hypothalamicopituitary control of the enzyme activity was discussed.

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In an attempt to investigate the mechanism by which hypertension accelerates atherosclerosis, fluctuation due to hypertension in aortic acid cholesteryl ester hydrolase (CEH), N-acetyl-β-glucosaminidase (NAGA) and acid phosphatase (AP) activities, were examined. SHRSP (stroke prone spontaneously hypertensive rats), SHR (spontaneously hypertensive rats) and WKR (normotensive Wistar Kyoto rats) were treated for 2 and 4 months with hypotensive drugs (reserpine, methyclothiazide and hydralazine); and arterial and venous enzyme activities were com- pared between the treated and nontreated rats. The results were also compared with those in DOCA-salt hypertension, which was induced by treating Wistar strain rats with DOCA (5mg/rats s. c. twice weekly for 1 month, 1% NaCl given as drinking water).
In spontaneously hypertensive rats, blood pres-sure of SHRSP (219mmHg) and SHR (172mmHg) was lowered to almost normal levels due to the hypotensive treatment, which hardly affected the blood pressure of WKR. Acid CEH activity in the aorta from nontreated SHRSP and SHR was significantly lower than the activity in the treated SHRSP and SHR respectively. Reversely, aortic NAGA activity was higher in the former group. However, both the activities in the vein was not different between the two groups. No effect of the treatment was observed in WKR. Accompanying a decrease in the enzyme activity there was a significant increase in aortic cholesterol content in the nontreated groups compared to the treated ones; the percent increase in cholesteryl ester was 108% (SHRSP) and 95% (SHR), and that in free cholesterol was 43% (SHRSP) and 14% (SHR).
In DOCA hypertensive rats, CEH and AP activities were significantly higher both in the aorta and the vein compared with those in the control rats. NaCl loading as drinking water also produced a similar result. These results indicate 1) that hypertension affected arterial CEH activity, leading to an accumulation of cholesterol, and 2) that an increase in CEH activity due to DOCA hypertension seemed ascribale to humoral factors.

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We studied the mechanism of regulation of cholinephosphotransferase (CPT) activity, which is one of the enzymes that synthesize lecithin, in hypercholesterolemic rabbit aorta and brain microvessels.
Atheromatosis in which lipid deposition occurs is related to hyperlipidemia and not infrequently, involves coronary arteries and aorta causing obliteration or dissection of involved arteries. Angionecrosis, another arterial disease, has relation to hypertention rather than hyperlipidemia and does not show lipid deposition. Angionecrosis is considered to cause cerebral bleeding.
In atheromatous arteries, phospholipids are increased as well as cholesterol esters which are the main component of deposited lipids. It has been reported that synthesis of lecithin is the most marked in phospholipids synthesized in atheromatous arteries. Cholesterol-fed (HCD) rabbits, that had been fed high cholesterol diet (1% cholesterol and 0.5% cholic acid), showed the prominent atheromatous lesions in the aorta, but no visible atheroma was seen in the brain microvessels. CPT activity was significantly higher in HCD rabbit aorta than that in control (ND) rabbit aorta. This result suggests that increase of lecithin in atheromatous lesion may be brought by increased CPT activity. In the brain microvessels of HCD rabbit, contrary, CPT activity was not changed compared with that in the control, and the changes of the other enzymes concerning lipid metabolism were not so significant that lipid deposition occurs in the vessels.
Portman reported that increase of lecithin was seen in atheromatous aorta after cholesterol content had been increased. The fact that CPT activity was increased in atheromatous aorta and not increased in non-atheromatous brain microvessels in the same hypercholesterolemic rabbit implies that the lipid deposition in the arterial wall may play an important role in activation of CPT activity. From the point of view of lipid metabolism, it was also suggested that the brain microvessels are not easily involved in lipid deposition by hyperlipidemia.
Deposited lipids of atheromatosis, that is, cholesterol, cholesterol oleate and triolein, did not activate CPT activity so much in particulate fraction of normal rabbit aorta. Nor did lipoproteins (VLDL, LDL, HDL) significantly increase the activity. The supernatant fraction of atheromatous aorta of HCD rabbit markedly increased the activity com pared with that of control. This means that some activating factor which activates CPT appeared in the process or result of lipid deposition in the arterial wall.

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We already reported an experimental model of atherosclerosis in rats which was produced in 6 weeks by loading massive doses of vitamin D₂ and atherogenic diet.
In the present study, we have studied lipid metabolism in the aortic walls of the atherosclerotic rats. The tests included lipid composition, fatty acid composition in cholesteryl ester (CE) fraction, CE synthesizing and hydrolase activities and prostacyclin production in the aortic tissue. We have also investigated the effect of PGI₂ on the CE synthesizing and hydrolase activities in the aorta in vitro.
Free and esterified cholesterol increased markedly in the aortas of the atherosclerotic rats, while triglyceride and phospholipid didn't increase significantly. Vascular FFA content reduced in the atherosclerotic rats. A high possitive correlation was observed between vascular deposition of CE (r=0.83) or free cholesterol (r=0.88) and the degree of arterial lesions at the aortas of the atherosclerotic rats.
Palmitoleic and linoleic acids in the CE fraction of the aortic wall reduced in the atherosclerotic rats, while oleic acid increased markedly.
The CE hydrolase activity at PH 4.5 increased slightly in the aortas of the atherosclerotic rats when compared to the normal one, while the activity at PH 7.4 decreased. The CE synthesizing activity increased significantly in the aortic wall of the atherosclerotic rats. The ratio of the CE synthesizing activity to the CE hydrolase activity was always higher in the atherosclerotic rats than in the control.
Prostacyclin production decreased in the aortic tissue from the atherosclerotic rats in proportion to the degree of the atheromatous lesion. These changes were normarized by the treatment with pantethine.
PGI₂-S didn't influence the CE hydrolase and synthesizing activities of the aorta at the concentrations equivalent to physiological concentrations of PGI₂ (10^-8-10^-7M) in vitro.
These findings were discussed in relation to pathogenesis and development of the atherosclerotic vascular changes.

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Two groups were prepared, one had been treated with enough doses of α-tocopherol nicotinate and the other was control. On these two groups, death rate, number of platelet, level of serum α-tocopherol, lipoperoxide (TBARS), and lipids were studied before and after the intravenous administration of peroxidized arachidonic acid (P. A. A.); 2.0mg/kg, 1.4mg/kg, 0.7mg/kg. Following results were obtainted;
(1) The death rate of the treated group after the injection of 1.4mg/kg P. A. A. was 22% (n=9) and that of the control group was 78% (n=8).
(2) Histologically, destruction of the tissue, bleeding and microthrombus were detected in the lung of dead cases. On the other hand, these changes were apparently mild in the lung of alive cases.
(3) The reduction rate of number of platelet was not so remarkable in the alive cases; 75.3±13.1% (n=6), as in the dead cases; 49.3±13.9 (n=7).
(4) Serum α-tocopherol level was decreased in both groups. TBARS level was slightly increased in the control group. Total cholesterol level and the ratio of α-tocopherol to cholesterol were decreased after injection of 1.4mg/kg P. A. A. Serum FFA level was elevated after the injection of P. A. A. and this change was more remarkable in the control group.
(5) Time course of α-tocopherol and TBARS after thee injection of 0.7mg/kg P. A. A. was observed. Day by day, α-tocopherol level of the prior treated group was decreased, but that of the control group was flat. TBARS level was increased in both groups three days after the injection of P. A. A.
The results imply that α-tocopherol may be comsumed quickly and defensively against a series of occurence produced by P. A. A. administration.

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Owing to the depelopment of Prostaglandin reserch, it has been known that the endothelial cell of blood vessels generate prostacyclin (PGI₂) which is protective for platelet aggregation and vasoconstriction.
On the other hand, Thromboxane A₂ (TXA₂) is a powerful stimulant of platelet aggregation and vasoconstriction. Both PGI₂ and TXA₂ are the derivatives from the prostaglandin endoperoxides PGG₂ and PGH₂.
It was also reported that these substances play an important role in the developement of cardiovascular disease.
In this report we investigated the effect of antiplatelet aggregating and vasoactive agents of PGI₂ release from rat aorta.
PGI₂ activity was assayed by the inhibitory effect on ADP-induced platelet aggregation. Thoracic aorta was isolated from 200g male wistar rat under pentobarbital anesthesia and cut into rings. The aortic rings were kept in cold KRP buffer and used for the experiment within 40min. The aortic ring was incubated in 0.5ml of 0.05M Tris HCl buffer (pH 7.5) per 1mg aortic ring at room temperature for 10min. Aliquot of this incubation medium (50μl) was added into 0.3ml of human PRP (Platelet Rich Plasma, count 300.000/mm³) and then incubated at 37°C for 2min. and ADP induced aggregation was evaluated.
When the aortic ring was incubated in the medium containing Dipyridamole (50 and 100μ/ml) or Trapymin (50 and 100μg/ml), PGI₂ release from aortic ring was significantly accelerated. The accelation of PGI₂ generation was inhibited by the preincubation of Indomethacin (11.5μg/ml).
Moreover, the aorta of rat intravenously injected with these agents (Dipyridamole 25mg/kg and Trapymin 30mg/kg) was incubated in the same condition. PGI₂ release was significantly increased in the aorta of rats injected with the agents as described above.
This PGI₂ generation were inhibited in the aorta of rats previously injected with Indomethacin (3.57mg/kg).
These agents have been established as the inhibitory agents for the platelet aggregation. As demonstrated in this paper, it is noteworthy that these agents have potentiating activity in the PGI₂ generation from the arterial wall.

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Lipid contents of human platelets were analysed by a thin-layer chromatography with flame ionization detection in 28 healthy adults and 57 patients with diabetes mellitus. The values of phosphatidylcholine, phosphatidylethanolamine and sphyngomyelin were higher in the diabetic group compared to those of the healthy group. Molar ratio of cholesterol/phospholipid (C/P) of the platelets decreased significantly in the diabetic patients than in the healthy group (0.01<P<0.02). From a view point of the relationship between serum lipoprotein and platelet lipid contents, only the molar ratio of cholesterol/phospholipid of the diabetic platelets correlated significantly with (total cholesterol-HDL cholesterol)/HDL cholesterol of the diabetics (r=0.35, P<0.01). It is of interest that the patients with the same lipids levels as healthy adult showed most lower values of C/P molar ratio of the platelets. These data provide us to conclude that the high levels of phospholipids in the diabetic platelets than healthy platelets were not necessarilly corresponded to the abnormalities of serum lipoprotein. The other factors except the serum lipoprotein have to be proposed to be clarified the mechanism of the higher phospholipid levels of platelets in patients with diabetes mellitus.

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The effects of dried Chlorella powder on lipid metabolism and pathological changes of aortae were investigated in cholesterol-fed rabbits, using clofibrate for comparison. Japanese white male rabbits were fed on a high cholesterol diet for 20 weeks in the following manner: 1) High cholesterol diet (0.5% cholesterol in normal stock diet), 2) High cholesterol diet plus 1% Chlorella, 3) High cholesterol diet plus 5% Chlorella, 4) High cholesterol diet plus 0.5% clofibrate.
Administration of Chlorella inhibited the increase of serum total cholesterol and phospholipid levels caused by cholesterol feeding. The percentage of atherosclerotic intimal involvement was significantly lower in Chlorella-fed groups than cholesterol-fed group. Clofibrate did not affect the levels of serum lipids, but it reduced the aortic intimal involvement.

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Cholesterol concentration of five kinds of Shellifish, eight kinds of cephalopoda or crustacea, eight kinds of eggs, ten kinds of meat, nine kinds of processing meat, 23 kinds of fishes, five kinds of processing fish meat, three kinds of processing fats and three kinds of treated milk, that is 74 kinds as a whole, is determined using colorimetric, enzymatic, thin layer chromatographic, and gas-liquid-mass-spectrometric method.
These values may be helpful for patient with antherosclerosis in dietary cure to prevent a development of the disease.

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Diet has a powerful effect on plasma cholesterol concentration, however these levels often vary among individual cases on the same diet. The most important indication for treatment of hyperlipidemia is for the prevention of atherosclerosis, a suspected but unproved benefit. Over past five years these has been an intense degree of interest in relation of HDL-cholesterol for the development of ischemic heart disease.
In this study, eight hospitalized patients, who were men aged under 65 years old, were kept on a formula diet constituting of 71g protein (28% of total calory), 129g carbohydrate and 20g fat (p/s ratio=1.8). After normalized VLDL-release and catabolism in plasma by the formula-diet, all subjects consumed the experiment-diet, which was 1500cal./day containing 105g protein (28% of total calory intake) and 50g fat (p/s ratio=1.7, 30% of total calory).
Fasting plasma sample which were collected before and after 34 days (average) of the experiment-diet therapy, were subjected to ultracentrifugation for isolation of lipoprotein-fraction and measurement therein of total cholesterol (TC), free cholesterol (FC), and triglyceride (TG).
As results, an increased intake in 500cal./day from formula-diet caused to following change; (1) TG and FC in VLDL slightly but significantly increased. (2) TC in LDL decreased in 6 of 8 subjects. (3) TC in HDL increased in 6 of 8 subjects, and FC in HDL and FC/TC in HDL decreased in 4 of 8 subjects.
These results indicated that 1500cal./day might be suited to keep the normalized plasma lipoprotein metabolism and to repair hyperlipidemia as the prevention of atherosclerosis.

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In view of the tendency toward vascular complications in diabetes mellitus and ischemic heart disease (IHD), platelet aggregation and plasma β-thromboglobulin (β-TG) levels were studied in 35 healty controls, 25 non-diabetic patients with IHD and 85 diabetic patients. Blood platelet from diabetic patients showed no significant platelet hyperaggregation induced by three aggregating agents (ADP, collagen and epinephrine), compared with controls and non-diabetic patients with IHD, and no significant differences was demonstrated in platelet aggregation between diabetics with diabetic microangiopathy and those without diabetic microangiopathy. Significant high plasma β-TG level was observed in diabetics in comparison to controls and non-diabetic patients with IHD. Patients with diabetic microangiopathy had more significantly elevated β-TG level than diabetics without, diabetic microangiopathy. Diabetics without diabetic vascular complications had no more significantly high β-TG level than controls and non-diabetic patients with IHD. High levels of plasma β-TG in diabetics with microangiopathy seemed to be due to platelet hyperfunction in vivo in those.

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It is well established that high blood pressure is an important factor in the pathogenesis of atherosclerotic disease. Clinically, the risk of incidence of thromboembolic complication in hypertensive patients is higher than normal persons. In hypertension, for example, renovascular hypertension, Angiotensin II (A II) is often elevated. On the other hand, the importance of platelets in the pathogenesis of thrombotic disease is also well known. There are several reports concerning A II effects on platelet aggregation but no reports about (1-Sar, 8-Ileu) Angiotensin II (Angiotensin II Antagonist) effects on platelet aggregation in vivo. In this point of view, we investigated A II and A II Antagonist effects on platelet aggregation induced by ADP in normotensive and hypertensive subjects. The results are summarized in Table 1 and Table 2. The present findings confirm that A II infusion increases the aggregating effect by ADP. And A II Antagonist can also have stimulatory effect and inhibitory effect on platelet aggregation by ADP. Further studies about the detail mechanisms of these phenomena are necessary.

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Effect of urokinase (UK) therapy on acute myocardial infarction (AMI) was investigated. Based on previously published results, UK was administered by concomitant administration of one shot (60, 000IU) and continuous infusion (300, 000IU/12 hours). In order to evaluate the effect of UK administration, 13 parameters in 4 items which reflects pathophysiological meanings of UK therapy in AMI was classified into 2-3 subgroups and got marks: Item I: the time from the onset of AMI to UK infusion—if it is within 8 hours, 10 marks are given; 8-24 hours, 5 marks, and more than 24 hours, zero. Item II: blood coagulation and fibrinolysis factors (fibrinogen, plasminogen, α₂-macroglobulin, antithrombin III and α1-antitrypsin)—if it's fluctuation is more than 50% of its pre-administration (or normal) value, zero mark is given; 25-50%, 5 marks, and less than 25%, 10 marks. If the value of FDP is more than 10μg, 10 marks are given; 2.5-10, 5 marks, and less than 2.5μg, zero mark. Item III: ECG patterns—If Q wave appears, zero mark is given and otherwise, 10 marks. If the time when ST segment returns to initial level is within 1-2 days, 10 marks are given, 3-4 days, 5 marks, and more than 7 days, zero mark. If coronary T wave does not appear, 10 marks are given and otherwise, zero mark. Item IV: serum enzymes (CPK, GOT, GPT, LDH and HBD)—if it's fluctuation is more than 2 times of pre-administration (or normal) value, zero mark is given; 2-1.5 times, 5 marks, and less than 1.5 times, 10 marks. If total score is more than 60 marks, such case is regarded to belong to “effective” group, and otherwise, “ineffective”. The four cases out of 8 AMI patients belonged to effective group, and the other four, ineffective group. In the 13 parameters measured in this study, two parameters showed significant difference between two groups: the time from the onset of AMI to UK administration, and the time of ST segment to return to normal level. Therefore, it is concluded that, in UK trial to AMI, UK is effective to recover elevated ST segment to normal level within 1-2 days, if UK (60, 000IU/one shot +300, 000IU/12 hours) is administered within 8 hours after onset of AMI.

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