Many studies have focused on the significance of remnant-like lipoproteins (RLP) with respect to the relationship between postprandial hyperlipidemia and atherosclerosis. A novel method to measure RLPcholesterol (RLP-C) by utilizing monoclonal antibodies to apo A-I and apo B was recently developed. We determined RLP-C levels in Japanese-American and Japanese subjects, and investigated their association with glucose tolerance, insulin resistance and serum lipids.
1) Fasting RLP-C was positively associated with total cholesterol (TC) and triglycerides (TG), and negatively associated with HDL-cholesterol (HDL-C). In particular, it showed a close positive association with the fasting TG level. An association between RLP-C and fasting serum glucose was not found, but fasting serum insulin showed a significant association with RLP-C among Japanese-Americans. The higher RLP-C level observed among Japanese-Americans may have been caused by higher TC and TG concentrations, as well as insulin resistance.
2) Investigation of the changes in RLP-C concentration during the glucose tolerance test showed that the area under the curve for blood glucose was significantly associated with the increase in RLP-C.
These results suggest that RLP-C significantly influences the pathogenesis of atherosclerosis as glucose tolerance worsens and hyperlipidemia develops, especially when low HDL-C levels are observed.

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In the previous study we clarified that postprandial lipid metabolism was delayed in individuals with visceral fat accumulation. In the present study, we investigated how abdominal visceral fat accumulation affected postprandial remnat lipoprotein metabolism.
Subjects with obesity and visceral fat area/subcutaneous fat area>0.4, or those without obesity and visceral fat area>100cm² for male (>90cm² for female) were defined as visceral fat accumulation(VFA). Midband lipoproteins analyzed by PAGE and plasma IDL-C levels determined by ultracentrifugation were used as indicators of remnant lipoproteins.
Individuals with VFA had midband lipoprotein more frequently and higher plasma levels of IDL-C both at 0 and 4 hours after oral fat loading than those without VFA.
These results suggest that accumulation of abdominal visceral fat causes delayed metabolism of plasma remnant lipoprotein, which may lead to the development of coronary atherosclerosis.

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Remnant lipoproteins have been identified as atherogenic lipoproteins. Recently, remnant-like particles (RLP), which are almost identical to the remnant lipoproteins, were measured rapidly using anti-apo A-1 and anti-apo B-100 immunoafinity gel suspension. To evaluate the association of RLP with the coagulation/fibrinolytic system which plays an important role in the pathogenesis of myocardial infarction, we examined the correlations between plasma levels of RLP and coagulation/fibrinolytic markers in patients with myocardial infarction.
Methods: The subjects were 107 patients with myocardial infarction not receiving antihyperlipidemic or anticoagulant agents. Blood sampling was performed at least 6 months or longer after the onset of myocardial infarction. We measured fasting blood concentrations of total cholesterol, triglyceride, HDLcholesterol, RLP-cholesterol, RLP-triglyceride, fibrinogen, factor VII (FVII) antigen, activated factor VII (FVIIa), tissue factor, prothrombin fragment 1+2, and plasminogen activator inhibitor-I.
Results: In simple regression analysis, the plasma levels of RLP-triglyceride showed significant positive correlations with plasma levels of FVIIa and the FVIIa/FVII ratio (r=0.21, p<0.05 and r=0.20, p<0.05, respectively). In normolipidemic patients (n=72), RLP-triglyceride showed a positive correlation with FVIIa (r=0.31, p<0.01), FVIIa/FVII ratio (r=0.34, p<0.01), and plasminogen activator inhibitor-I (r=0.24, p<0.05). In hyperlipidemic patients (n=35), RLPtriglyceride showed a positive correlation with FVIIa (r=0.35, p<0.05), FVIIa/FVII ratio (r=0.37, p<0.05). None had significant correlations with plasma levels of the FVII antigen, tissue factor, or prothrombin fragment 1+2.
Conclusions: RLP-triglyceride may be involved in the pathogenesis of myocardial infarction by activating the extrinsic coagulation pathway and suppressing fibrinolytic activity.

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Second derivative of photoplethysmogram (SDPTG) or acceleration plethysmogram (APG) is the second derivative wave of the photoplethysmogram. SDPTG has been developed to allow more accurate recognition of the inflection points on the original plethysmographic wave, ie, anacrotic or dicrotic notches. It has been recognized as the independent examination tool for vascular properties.
SDPTG includes 4 systolic waves and 1 diastolic wave, namely a-wave (early systolic positive wave), b-wave (early systolic negative wave), c-wave (late systolic reincreasing wave), d-wave (late systolic redecreasing wave) and e-wave (early diastolic positive wave).
The ratio of the height of the each wave to that of the a-wave (b/a, c/a, d/a and e/a) are usually used for wave analyses.
We previously reported characteristic age related wave changes of SDPTG in 600 subjects (each 50 men and 50 women in each decade from the 3rd to the 8th) in our health assessment center (Hypertension, 1998; 32: 365-370.).
SDPTG-AI increased with augmentation index of original photoplethysmogram which is known to increase with increasing age, and is defined as the ratio of the amplitude of the late systolic component to that of the early systolic component of the original plethysmogram.
The b/a increased with age and c/a, d/a and e/a decreased with age. Thus b-c-d-e/a was taken as the aging index of SDPTG (SDPTG aging index: SDPTGAI) which increased with age. SDPTG (Y) increased with age (X) as Y=0.023X-1.515, r=0.80, p<0.001).
Similar distribution of vascular ages were seen in different districts group, including women in Toba city in Mie prefecture, subjects in shinjuku in Tokyo and patients in Broussias Hospital in Paris.
SDPTGAI increased with vascular stiffness represented by inceased b/a and increasing reflection wave represented by decreasing d/a. Vascular age estimated by SDPTG=43.5SDPTGAI+65.9.
SDPTGAI and vascular age were significantly higher in patients with a history of hypertension, diabetes mellitus, and hyperlipidemia than in subjects without any disease (p<0.01).
The possibility of arteriosclerotic disease can be considered when vascular age is higher than actual age. Though cut-off value of the difference of vascular and actual ages are under examination, the tentative cut-off value is a difference of 15-20 years, which will provide us useful information for screening of arteriosclerotic diseases.
A new type of apparatus (Fukuda FCP series) provides full automated detection of each indices and prints out within 30 seconds, which will be widely used for noninvasive evaluation of arteriosclerosis through vascular age.

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