The following themes were described about the relationship between lipid metabolism and lipid accumulation in arterial wall.
1. Introduction of metabolism in arterial wall
(1) Lipid metabolism
(2) Protein metabolism
(3) Glucose metabolism
2. Lipoprotein metabolism in arterial wall
(1) Lipoprotein and arterial wall
(2) Lipoprotein and lipid accumulation
3. Cholesterol metabolism in arterial wall
(1) Cholesterol ester metabolism in lysosomes
(2) Cholesterol ester metabolism in microsomes
4. Phospholipid metabolism in arterial wall
5. Triglyceride metabolism in arterial wall
6. Free fatty acid metabolism in arterial wall
7. Lipoperoxide in arterial wall
8. Risk factors and lipid metabolism in arterial wall
(1) Thrombosis and lipids
(2) Hormone and lipid metabolism
(3) Hypertension and lipid metabolism
9. Regression of atherosclerosis

View full abstract

The composition, structure and metabolism of high density lipoprotein (HDL) were reviewed and the relationship between HDL and atherosclerosis was discussed.
The metabolism of hepatic HDL and intestinal HDL were described separately, because apoproteins of nascent HDL from two sources are different. A metabolic pathway was proposed in which nascent HDL grows to HDL₃ by taking cholesterol and esterifying it and then HDL₃ changes to HDL₂ by increasing lipid content.
HDL has anti-atherogenic erect and the amount of HDL is clinically estimated by measuring cholesterol in it. HDL is separated from VLDL and LDL by precipitating them with heparin and MfCl₂.
The results obtained by heparin-MnCl₂ method were compared to those obtained by ultracentrifugation, phosphotungustate-MnCl₂ and dextransulfate-MgCl₂ methods and good correlation was found among all methods.
The normal level of plasma HDL-cholesterol in Japanese was 56±16mg/dl for men and 61±15mg/dl for women. These values are higher than those reported in western countries and the reason was investigated. HDL-cholesterol levels in cord blood were similar in all countries and people from western countries who were living in Japan and eating Japanese food had similar HDL-cholesterol levels to Japanese. These results indicate that high HDL-cholesterol of Japanese is caused by environmental factors rather than genetic factor.
HDL-cholesterol levels were measured in several diseases. HDL-cholesterol was significantly decreased in hyperlipidemia, obesity, coronary heart disease and diabetes mellitus and it was variable in liver disease.

View full abstract

The pig liver was perfused with Krebs-Ringer bicarbonate buffer containing glucose, bovine serum albumin, amino acids and washed human erythrocytes and VLDL metabolism was studied.
Hepatic catabolism of VLDL to IDL or LDL was investigated by adding ¹²⁵I-VLDL to the perfusate, perfusing the liver for 4 hours and measuring adioactivities in IDL and LDL. No radio-activity was observed in IDL and LDL ranges and hepatic catabolism of VLDL was excluded.
Since VLDL was not catabolized by the liver, VLDL obtained from liver perfusion is considered to represent nascent VLDL. Physical and chemical characteristics of perfusate and plasma VLDL were compared and VLDL metabolism was investigated.
The size of VLDL particle was measured by laser selfbeat spectroscopy. It was shown that nascent VLDL is relatively large particle and uniform in size. Therefore, it is considered that various VLDLs which are seen in plasma are caused by the action of lipoprotein lipase.
Perfusate VLDL contained more lipids and less protein than plasma VLDL and the most striking difference was seen in phispholipid.
Apoproteins of VLDL were analyzed by Sephadex G-200 column chromatography and 7.5% polyacrylamide gel electrophoresis containing 0.1% SDS. Elution pattern from the column showed that apoprotein of nascent VLDL consists mainly of apoB. Perfusate VLDL comprise a small amount of apoC, but is devoid of apoE. The same result was obtained from analysis by polyacrylamide gel electrophoresis. In contrust, nascent HDL is rich in apoE and plasma HDL is almost devoid of apoE. The studies on the incorporation of ¹⁴C-leucine into apoproteins during perfusion showed that the estimated specific activities of apoA-I and apoE are virtually the same for VLDL and HDL suggesting one pool for these apoproteins. In contrust, the specific activity of apoC-II isolated from perfusate VLDL was significantly higher than that isolated from perfusate HDL suggesting the presence of more than one pool. These results indicate that a small amount of apoC is secreted in VLDL by the liver, but apoE is transfered from HDL to VLDL in the cirulation.

View full abstract

Postheparin plasma lipoprotein lipase and hepatic triglyceride lipase have been studied in human and rats. Two lipases were measured separately with the use of antiserum prepared against hepatic triglyceride lipase.
Two lipase activities Change depending on the amounts of heparin administered and time of sampling. After administration of 10U/kg heparin, both lipoprotein lipase and hepatic triglyceride lipase reached maxima at 10min. Lipoprotein lipase in men was slightly, but not significantly, lower than that in women. Hepatic triglyceride lipase in women varied greatly. Older rats had lower activities of both enzymes. After overnight fasting, two lipase activities decreased approximately 40% in rats. The administration of insulin in a daily dosage of 2 units for 10 days increased lipoprotein lipase activity in rats, indicating that this is an insulin-dependent enzyme.

View full abstract

Recent biochemical, genetic, and ultrastructural studies have shown that nonhepatic human cells, such as fibroblasts, lymphocytes, and aortic smooth muscle cells, utilize a specific metabolic pathway, the low density lipoprotein (LDL) pathway, to supply themselves with cholesterol. The LDL pathway, which was proposed by Goldstein and Brown in 1976, was outlined and discussed in the first half of the present report.
In the last half of the paper, evidence was presented that the activity of sterol synthesis in the cells is regulated by a metabolite derived from mevalonate, possibly lanosterol, as well as by cholesterol.

View full abstract

In this study the role of high density lipoproteins on the plasma LCAT reaction was reported. When the fresh plasma was filtered through Sephadex G200, the enzyme peak coincided with HDL which was shown by lecithin determination. The association of the enzyme with HDL was demonstrated by the determination of LCAT activity present in D=1.25 supernatant fraction which had been separated after the incubation of inactivated HDL with LCAT. ApoA-1, which is one of the two major apoproteins present in HDL, activated the LCAT reaction when lecithin: cholesterol emulsions were used as substrate. To investigate the mechanism of the activation of LCAT reaction by ApoA-1, apoHDL-Sepharose was prepared and was subsequently used for the binding with LCAT. The binding of the enzyme to apoHDL-Sepharose was almost negligible, however, weak but definite binding of LCAT to lecithin-apoA-Sepharose was shown.
The physiological significance of the plasma LCAT reaction remains to be disclosed. However, the fact that the plasma LCAT reaction is higher in hyperlipemic diabetics and in extreme obesity, supports some role of LCAT reaction on plasma triglyceride metabolism.

View full abstract

Plasma HDL cholesterol was determined by the enzymatic cholesterol assay after precipitation of apo B containing lipoproteins with heparin and manganese chloride. Apoprotein A-I and A-II were measured by the rocket immunoelectrophoresis with the specific antisera for each of the apoproteins. The levels of HDL cholesterol in 8 healthy young men and 8 women were 56±6 and 60±7mg/100ml, respectively. The levels of A-I and A-II in 10 healthy young men were 119±10 and 112±18U/100ml, respectively. The apoprotein levels in 9 young women revealed 135±13 for A-I and 115±12U/100ml for A-II. (The concentration of apo A-I and A-II in the reference serum was taken arbitrarily as 100U/100ml). The levels of A-I was significantly higher in women but no sex related difference was observed in A-II level. The results were compatible with the abundance of HDL₂ in women. The patients with liver disease showed decreased levels of A-I and A-II in same extent suggesting the decrease mainly in HDL₃ concentration. It is also important to consider the ratio of HDL cholesterol and A-I since the ratio is higher in HDL₂. In addition to the HDL cholesterol determination, the measurement of A-I and A-II concentration provide us more detailed informations on HDL metabolism.

View full abstract

In various tissues the liver plays a major role in the clearance of plasma lipoprotein. The hydrolysis of triglyceride-rich lipoprotein (chylomicron and VLDL) is mediated by lipoprotein lipase (LPL) localized on the capillary endothelial surface and but the role of hepatic triglyceride lipase (HTGL) in lipoprotein metabolism is still not clear.
Recent studies indicated that the liver took up and hydrolyzed chylomicron-remnant, a product which chylomicron was degradated by LPL. In this study we have determined the fate of labeled chylomicron in circulating blood following intravenous injection in the normal and the supradiaphragmatic rat. And the effect of various sizes of chylomicron on the uptake of the lipoprotein in the liver was also investigated.
As a result, the apparent half-life of injected chylomicron was 2.5min in the normal rat and prolonged to more than 5min in the supradiaphragmatic rat. The radioactive ratio of triglyceride to cholesterol in the blood and the liver was not different from the labelled origin during 10min after the injection. The liver hydrolyzed the large-chylomicron far more efficiently than the middle or the small-chylomicron.

View full abstract

In order to investigate the Metabolism of HDL, approx. 50g/day of alcohol for 7 days, 1.5g/day of cholesterol for 7 days and 750mg/day of niceritrol for 4 weeks were administered for 30-45 years old female subjects. Then, serum lipids, lipoproteins, lipoprotein lipids and apoproteins were determined before and after administrations.
Results: 1) In the alcohol group, HDL and HDL-cholesterol levels increased even though the subjects still did not show the increase of VLDL levels. However, in the HDL subfractions, HDL₂ decreased and HDL₃ increased significantly. Apo-AI/AII ratio decreased.
2) In the cholesterol group, serum concentrations of LDL, VLDL and HDL increased. In the HDL subfractions, both of HDL₂ and HDL₃ increased simultaniously, and increase of HDL₃ was more dominant than that of HDL₂. β/α ratio increased.
3) In the niceritrol group, LDL and especially VLDL levels decreased, and HDL and HDL-cholesterol levels increased. In the HDL subfractions, both HDL₂ and HDL₃ increased simultaneously. In this group, increase of HDL₃ was also dominant. β/α ratio decreased.
Discussion and conclusion: Reciprocal relationship between VLDL and HDL have been reported. So, the increase of HDL in the niceritrol group seems to be reasonable. In the cholesterol group, it may be the facts that the increase of HDL occured by the acceleration of VLDL catabolism which had been caused by the increase of VLDL produced in the cholesterol administration. In these groups, the stream of HDL metabolism seems to move normaly. However, it seems that the stream of HDL metabolism is so disturbed by the alcohol administration that the decrease of HDL₂ and retension of HDL₃ occrued.
From the above mentioned results, it may be concluded that the direction of HDL metabolism should be from HDL₃ to HDL₂.

View full abstract

High density lipoprotein (HDL) cholesterol was assayed with heparin-MnCl₂ precipitation method in patients diagnosed as diabetes mellitus. Mean±standard deviation of serum HDL-cholesterol levels in male patients (numbers=162) was 54.1±12.3mg/dl and those in female patients (n=157) was 58.0±12.1mg/dl. In male patients who had been drunk alcohol, mean HDL-cholesterol level was significantly higher than non alcoholic male patients (55.9±12.0 (n=50) vs. 51.9±11.6 (n=79)).
Family tolerance of diabetes mellitus, cerebro-vascular diseases and myocardial infarction did not show any significant changes on the HDL-cholesterol levels. HDL-cholesterol distributions by 5-year age groups in male and female patients were analysed. Between 35-59 years, HDL-cholesterol levels in female were higher than in male. After 55 years HDL-cholesterol levels decreased gradually in female, however HDL-cholesterol levels in male were almost constant through all years observed.
There were no correlation between fasting blood sugar and HDL-cholesterol levels. HDL-cholesterol levels were negatively correlated with serum triglyceride cocentration and relative body weight In female between 40-59 years the incidence of aortic elongation and or aortic calcification in chest X-ray was higher in lower HDL-cholesterol patients. The incidence of complications proteinuria, abnormal ECG findings and diabetic retinopathy were also higher in lower HDL-cholesterol patients than higher HDL-cholesterol patients. These results suggest that lower HDL-cholesterol levels might accelrate the atherosclerosis in diabetic patients and HDL-cholesterol levels might not be dpeend on the controled state of blood sugar.
We had investigated the effect of different forms of antidiabetic treatment on HDL-cholesterol levels. Insulin-treatment group showed higher HDL-cholesterol levels than non insulin-treatment groups. Mean HDL-cholesterol levels of sulfonylurea group was lower than dietary group, however these differences were not significant statistically. Patients suffered from cerebral hemorrage, cerebral infarction or myocardial infarction showed low HDL-cholesterol levels.

View full abstract

The change in lipid composition of serum HDL was investigated and effects of Y-9738 on the serum HDL were studied in patients with atherosclerosis.
Methods: Serum was added NaphT MgCl₂ or Heparin Mn and centrifuged at 3000r.p.m. for 10min. HDL cholesterol and HDL phospholipids were determined in the supernatant fraction. Subfraction of phospholipids were separated of the Silicagel G thin layer chromatography. Y-9738 was given orally 900mg/day for 4 months. α₁ lipoprotein was analyzed according to Laurell's immunoelectrophoresis before and after administration of Y-9738.
Results and discussion: (1) The serum with low HDL cholesterol showed a low HDL total phospholipid, low HDL phosphatidyl choline and low ratio of Lysophosphatidyl choline to phosphatidyl choline, but it did not show a low HDL phosphatidyl ethanolamine in patients with atherosclerosis.
Therefore, serum HDL cholesterol levels were not directly proportional to the HDL phospholipid levels, although there was a highly significant correlation between these two variables.
(2) The ratio of HDL cholesterol to HDL phospholipid was low in patients with atherosclerosis as compared with normal subjects. (0.377-0.553)
(3) Y-9738 significantly increased HDL cholesterol, HDL phospholipid and α₁ lipoprotein, regardless of initial HDL cholesterol levels.
These results are quite different from those of previous reports suggesting that some drugs increased the HDL cholesterol in patients with atherosclerosis, only when the initial HDL cholesterol was below the normal values.
(4) No change in the ratio of HDL cholesterol to HDL phospholipids was observed after administration of Y-9738.
A very unbalanced increased of lipids and apoprotein was not observed in HDL after Y-9738 administration.

View full abstract

Triglyceride-rich lipoproteins (Chylomicron and VLDL) are proven to be heterogenous in their size and chemical composition and the largerr particles are supposed to be catabolized to the smaller particles by the lipoprotein lipase (LPL). In order to investigate the VLDL metabolism, VLDL has been previously separated into subfractions by preparative ultracentrifugation, gel chromatography and so forth. Recently, it was reported that VLDL could be separated into seven subfractions by rate zonal ultracentrifugation.
In this paper, we report the compositional changes of lipoproteins, especially of VLDL subclasses, before and after the treatment with drugs which are supposed to increase the removal of TG-rich lipoproteins. We also speculate on the changes of HDL isolated by zonal ultracentrifugation.
1) The each subfraction of the VLDL is different in size and composition, and the chemical composition of VLDL subclasses was also different between the type V and type III hyperlipoproteinemias.
2) On oxandrolone treatment, the concentration of VLDL, of all VLDL subclasses and of IDL was reduced in type V patient, and the distribution of VLDL subclasses was changed remarkably, hence coming to resemble that in normal subjects.
3) In the type V patient, in whom HDL-₃ was reduced and HDL-₂ was absent, the concentration of HDL-₃ was moreover reduced after oxandrolone treatment and this HDL-₃ emerged later from the zonal rotor than before, implying increase of this HDL-₃ density.
4) Apoprotein-E (ARP), which appeared abundantly in all of the VLDL subclasses in the type V patient, disappered completely from all of the VLDL subclasses after oxandrolone treatment.
5) On clofibrate treatment, the concentration of VLDL, of VLDL subclasses and of IDL was remarkably reduced in the type III patient, and the fractions which appeared to be the chylomicron remnant and Sf-30 VLDL decreased preferencially among VLDL subclasses after treatment. Moreever, there appered another one predominant peak between the density of IDL and LDL which might be speculated as the remnant particles.
6) In this type III patient in whom the content of HDL-₃ was reduced and HDL-₂ was missing before treatment, there newly appeared HDL-₂ peak other than HDL-₃ fraction after clofibrate treatment.
7) Apoprotein-E, which was observed in high abundance throughout all the VLDL-subfractions in the type III patient, still remained predominant apoprotein in all VLDL subfractions after clofibrate treatment.

View full abstract

Serum lipoprotein levels were studied in 7 patients who had an attack of myocardial infarction under 40 years old (IHD group) and 4 subjects with no attach (non IHD group). 5 subjects in IHD group had a hyperlipoproteinemia and 2 subjects had a normolipoproteinemia, all IHD subjects were maken certain about the abnormality of coronary artery by coronary angiography. Non IHD subjects had also a hyperlipoproteinemia, but did not have the abnormality of coronary artery.
1) There were no differences in the ratio of major lipoprotein fruction's Protein/TC, Protein/TG, Free Chol/TC and Free Chol/TG between IHD group and non IHD group.
2) There were no differences in the ratio of VLDL-TC/TG and the level of LDL-TC between two groups, but the levels of HDL-TC in IHD group with hyperlipoproteinemia were lower than that in IHD group with normolipoproteinemia and non IHD group.

View full abstract

The activity of lipoprotein lipase varies in different tissue. Membrane-bound lipase have different reaction velosities than do sulubilized lipase by heparin. In this study, the catalytic rate of lipoprotein lipase was determined from the perfused rat heart. Rat chylomicron and human very low density lipoprotein (VLDL) were used as substrate.
Materials and Methods
The experimental procedure is fundamentally that described by C. J. Fielding et al. The hearts were isolated from male Sprague-Dawley rats (350-400g) after an overnight fast and perfused with a modified recirculating Langendorff apparatus. The perfusion was carried out using Krebs-Hens eit bicarbonate buffer gassed with 95% O₂ and 5% CO₂. ³H labeled human VLDL, rat chylomicron, 15% w/v of Bovone Serum Albumin, 0.04% v/v of three fold concentrated recalcified citrated plasma, from which LDL and VLDL had been excluded, were added to perfusion medium. Approximately 1.0 micro mol TG/ml of lipoprotein substrates were perfused through the heart. The perfusion period was 20-30min, during which 6 duplicate 0.2ml samples were drawn from the reservoir and the kinetic constant, maximal reaction velocity (Vmax), was determined from the specific activity of the extracted ³H-TG.
Results
Lipoprotein TG was hydrolysed by perfusion through the rat hert heart. Approximately 1.0 micro mol/ml of the lipoproteins represented zero order kinetics with both human VLDL and rat chylomicron. The calculated Vmax of human VLDL was 0.057±0.004 micro mol/min and that of rat chylomicron was 0.06±0.00 micro mol/min. These results indicate that the heart lipoyrotein lipase is satulated with a physiologically normal TG concentration. The addition of LDL to the medium decreased the maximal removal rate of TG. An inhibitory effect on lipoprotein lipase activity was evidenced by abnormally high LDL cholesterol concentration.
Conclusion
Assay by rat heart perfusion leads to a clear understanding of the physiological activity of lipoprotein lipase supported on the vascular surface of the heart than do measurement after solibulization by heparin.
The human VLDL is an active substrate for rat heart lipoprotein lipase and the kinetic constant is close to that of rat chylomicron.
An abnormal increase of serum LDL cholesterol might inhibit lipoprotein lipase activity on the vascular surface of the heart.

View full abstract

A study was made on clinical and biochemical features of sibling patients, a 13 year-old girl and a 15 year-old boy, with hyperchylomicronemia. They both were usually in good health and asymptomatic. Neither hepatosplenomegaly nor xanthomas were observed. Serum triglyceride concentrations were very high, 1094mg/dl and 1090mg/dl, but cholesterol levels were within normal range on a mild fat-restricted diet. The lipoprotein pattern on polyacrylamide gel disc electrophoresis revealed a high chylomicron peak in each patient but normal patterns were observed in other relatives.
In our patients, analysis of apoprotein of triglyceride-rich lipoproteins demonstrated the lack of apo C-II which is an important activator for LPL. Although a marked reduction in LPL activity was observed by standard assay procedure of PHLA, the activity was completely recovered by addition of normal serum or purified apo C-II to the assay mixture. These results indicate that the patients are not really deficient in LPL but the cause of chylomicronemia is a deficiency in its activator.
Their parents who had normal lipoprotein cencentrations were first cousins. The activating power of their sera upon guinea pig postheparin lipolytic activity were reduced approximately a half of the control values, suggesting that there was a reduction of apo C-II level in both parents. However the father had almost normal LPL activity in postheparin plasma, and the activity was not influenced by the addition of the normal serum.
Our observations in thie study strongly suggest that familial apo C-II deficiency is transmitted as an autosomal recessive mode of inheritance and heterozytotes have no abnormalities of plasma lipid and lipoprotein concentrations in spite of the reduced plasma apo C-II levels.

View full abstract

In order to study the effect of Triton WR1339 on apoproteins in more detail and specifically, to investigate the role of HDL apoproteins on VLDL catabolism, we have measured changes in apoprotein concentrations of whole plasma and lipoproteins at various times after injecting Triton WR 1339 into rats.
Monovalent antisera to sereral key rat apoproteins were used to quantitate changes in apoprotein concentration.
The large increase in plasma triglyceride and cholesterol (mostly confined to the VLDL fraction) was preceded by a rapid fall in the concentration of HDL and more particularly in the reduction of HDL apoprotein. The fall in HDL protein was due to the removal of AI, ARP and C proteins, all of which appeared in the d>1.21 fraction presumably as lipidfree or lipid-poor complexes.
We suggest that the presence of intact HDL is probably essential for VLDL catabolism and therefore the absence of intact HDL cofactor comlex is the primary cause of the massive increase in plasma triglyceride which follows Triton injection.

View full abstract

Apo B is a major protein of low density lipoprotein. Unlike most of other apolipoprotein, Apo B is a water-insoluble protein. Many investigators have attemped to solubilize Apo B with reagents which commonly used to unfold proteins, but were in vain for Apo B. Although some patially solubilized Apo B, Apo B still remained a big aggregate which was impossible for chemical or structual studies. Therefore, there is very little information available in literature. Even for the simple information as molecular weight of Apo B is still very controversial. We developed a new solubilization method of Apo B using copper.
1) Human Apo B in 6M guanidine-HCl became completely soluble after overnight stirring with Cu²⁺ in cold room.
2) The aggregation and viscosity of Cu²⁺-treated Apo B (Cu²⁺-Apo B) decreased and dissociated into 3 to 4 subunits. The molecular weight of Apo B ranged from 75000 to 90000.
3) Anti-human-Cu²⁺ Apo B rabbit serum gave single precipitin line with human whole plasma or low density lipoprotein. Although the separation of Cu²⁺-Apo B on DEAE-Sephacel was not complete, the above results obtained indicate that ApoB consists of at least three polypeptides.

View full abstract

The effect of insulin on a lipid content of the aorta and lipid distribution of the lipoprotein was studied in normal rabbits.
The study was performed on 12 male rabbits, being divided into two groups; one group (7 animals) was injected long acting insulin (1 unit/kg daily) (insulin-group) and the other (5) was used as control (control-group). The food (commercial rabbit pellet) intake was limited 200g daily.
Three months later, the blood collected in the fasting state for the determination of blood sugar, IRI and lipoprotein, thereafter the aorta was removed for the determination of cholesterol (Ch) and cholesterol ester (Ch-E) in the wall of the aorta.
There were no significant differences between two groups in weight gain, blood sugar and IRI. Ch content in the aorta was higher in insulin-group (2.96±0.28mg/g wet weight) than in controlgroup (2.28±0.12mg/g wet weight), though the difference was not significant. Ch-E content in the aorta was higher in insulin-group than in controlgroup, too. HDL-Ch levels were similar in two groups. LDL-Ch levels in insulin-group (12.8±1.4mg/dl) were significantly higher (p<0.05) than that in control-group (7.3±1.5mg/dl).
As a result of this study, it is suggested that insulin may have atherogenic action in the normal rabbit, probably by means of an increment of LDL-Ch.

View full abstract

Enzymatic staining methods for cholesterol, triglyceride and phospholipid were carried out to demonstrate them which were deposited on the aortic walls of the atherosclerosis.
Therefore, this staining methods are very useful to clarify the location of the each component of deposited lipids on the aortic wall.
Using this enzymatic methods, because of the comprehension for the lipid-laden or containing materials on the atherosclerotic lesions, our methods have the advantage of resolving the atherosclerosis.

View full abstract

A total of 556 semiconsecutive autopsied hearts in Japanese was subjected for macroscopical study for narrowing of the coronary artery, using multiple cross sectioning method according to WHO technical report. Grade of coronary narrowing was estimated as coronary narrowing index (CNI) which was calculated as a total of score representing 0 as no luminal narrowing, 1 as minimal, 2 as 25%, 3 as 50%, 4 as 75% and 5 as 100% narrowing or obstruction, in 3 main branches consisted of the anterior descending branch, circumflex branch and right coronary artery.
Significant average coronary narrowing more than 5 in the CNI, was observed at the 4th decade and later of male and at the 5th decade and later of female, with 10 years delay in female to male. The CNI in cases without any risk factors for atherosclerosis, increased with linear parallelism to growing age in male showing more than 5 of the CNI at the 5th decade or later, and it increased with a dome formation at the 5th to 6th decade in female with not beyond 5 of the CNI at any age group.
The CNI was significantly higher in the ischemic heart disease (IHD) including myocardial infarction than in any other miscellaneous diseases. In the IHD, extensive subendocardial and massive necrosis type myocardial infarction showed higher CNI than scattered necrosis type infarction or IHD without infarction. Diabetes mellitus was complicated to the IHD with higher incidence than any other diseases, and its existence increased the CNI by 50% compared to its absence.
Hypercholesterolemia more than 230mg/dl increased markedly the CNI at the 5th decade of male and moderately at every decade of female. Hypertension more than 150/90mmHg increased the CNI at the 6th decade of male and at every decade of female with a dominancy of female. The combination of both, increased the CNI more markedly in female. Complication of hypercholesterolemia to diabetes mellitus accelerated the coronary narrowing by 70% compared to its absence. The age specific acceleration of the CNI in male was partly related to coronary thrombosis superimposed to atherosclerotic narrowing.
The general tendency of progression in the CNI showed a considerable similarity to that of the aortic sclerosis in the same materials. The sex difference in the coronary narrowing was explained partly by different connective tissue reaction to mechanical stimulation and a protection mechanism against atherosclerosis through female hormone secretion.

View full abstract

In order to analyze the role of thromboxane A₂ (TX-A₂) during human platelet aggregation, changes in stable thromboxane B₂ (Tx-B₂) was studied with radioimmunoassay by Tx-A₂ ¹²⁵I-tyramide. Platelet aggregation was induced by ADP, adrenalin, collagen, arachidonate and Tx-A₂ mixture. Amounts of Tx-B₂, ATP, ADP, cAMP and cGMP in platelet rich plasma and platelet poor plasma were measured before and during aggregation.
ATP and ADP were released out of platelets in aggregation by any agents. However, the concentration of Tx-B₂ with ADP- and adrenalin-induced aggregation was remarkably lower than with collagen-, arachidonate- and Tx-A₂ mixture- induced aggregation. cAMP level was decreased during aggregation, but did not relate to Tx-B₂ level.
These results suggest that Tx-A₂ involves in platelet aggregation in different ways according to stimulating agents.

View full abstract

Cyclic GMP (c-GMP) is an important key substance in cell function, however, the related mechanisms have not been entirely elucidated as the content of this nucleotide within the cell is so small that an accurate estimation was difficult. We designed a microassay for cyclic GMP in 500μg d.w. of tissue samples, using succinylation, and were able to assay, separately, the content of cyclic GMP in the intima or media of the arterial wall. In addition, we attempted to develop a method for a simultaneous determination of both cyclic AMP and cyclic GMP in a small amount of the same assay mixture. 500μg d.w. of intima or media of rabbit aorta was prepared under a streomicroscope. After deproteinization and lyophilization, the samples was dissolved with 60μl of H₂O and 30μl of succinylation mixture (40mg succinic anhydride dissolved in 0.9ml dioxane was added: triethylamine=9:1). After succinylation, 40μl of each of the tissue extractions were sampled to determine the levels of cyclic AMP and cyclic GMP. The radioimmunoassay was performed, using YAMASA's kit. The recovery rates of cyclic AMP and cyclic GMP in our method were 86.2±1.2% and 87.6±1.3% respectively. The levels of cyclic GMP in the intima and media of aorta of cow, pig and rabbits were estimated to be, intima: 0.18±0.02, 0.06±0.03 and 0.20±0.01 pmole/mg protein, media: 0.08±0.01, 0.04±0.01 and 0.09±0.01. The cyclic GMP levels in the intima of aorta of cow and rabbits were high as compared to levels in the media and this difference was statistically significant (p<0.05).

View full abstract