Michiya Yamamoto

Paraoxonase gene polymorphism in Japanese subjects with coronary heart disease.

We investigated the association of paraoxonase (PON) gene polymorphism with both the occurrence of coronary heart disease (CHD) and the severity of coronary artery stenosis in Japanese subjects. PON is a protein associated with plasma HDL. It has been hypothesized an A/B (Gln 192-->Arg) polymorphism of PON may be involved in the pathogenesis of CHD, especially among subjects with non-insulin-dependent diabetes mellitus (NIDDM). The polymorphism was determined in 134 patients with myocardial infarction (MI) or angina pectoris, and in 252 healthy subjects as controls. The frequencies of the AA, AB, and BB genotypes in the patients were 15, 50 and 35%, respectively, and these frequencies did not differ from those in control subjects (14, 49, and 37%). The relative risk of CHD was not found to be associated with these genotypes. These data also were similar among selected subgroups (patients with MIs, those with a low-risk lipoprotein profile for CHD, and those with NIDDM). Neither the number of affected vessels nor Gensinis scores differed among the genotype groups. Our case-control study in Japanese subjects did not show that the PON A/B polymorphism is associated with a risk of CHD.

Significance of angiotensin I-converting enzyme and angiotensin II type 1 receptor gene polymorphisms as risk factors for coronary heart disease

The D allele of an insertion/deletion (I/D) polymorphism in the angiotensin I-converting enzyme (ACE) gene is associated with a risk of myocardial infarction, and the relative risk associated with the ACE D allele is increased by the C allele of an angiotensin II type 1 receptor (AT1R) gene polymorphism (an A-->C transversion at nucleotide position 1166) [28]. The relation of the ACE and AT1R gene polymorphisms to coronary heart disease and the severity of coronary artery stenosis has now been investigated in 133 patients with myocardial infarction (MI) or angina pectoris who underwent coronary angiography and in 258 control subjects. The frequency of the ACE DD genotype as compared with non-DD was significantly higher in the patients who experienced an MI and in the low-risk patients than that in the controls (P < 0.05). The DD genotype showed a significantly increased risk of MI (odds ratio 1.85). The frequency of the AT1R A/C genotypes did not differ between the patients and the controls. The severity of coronary stenosis in the patients was estimated by the number of affected vessels (> 75% stenosis) and the coronary score of Gensini. Neither the number of affected vessels nor the coronary score differed among the ACE I/D genotypes. However, the number of affected vessels was significantly greater in patients with the AT1R AC genotype than in those with the 4A genotype (1.93 +/- 0.27 vs. 1.27 +/- 0.99; P < 0.05) (CC genotype was not found in the patients). After excluding patients with diabetes mellitus, the coronary score of those with the AC genotype was also significantly higher than in those with the AA genotype (51.7 +/- 34.4 vs. 18.2 +/- 23.3; P < 0.01). These results suggest that the ACE D allele is associated with the occurrence of myocardial infarction, while the AT1R C allele is involved in the development of the coronary artery stenosis.

Suppression of plasma cholesteryl ester transfer protein activity in acute hyperinsulinemia and effect of plasma nonesterified fatty acid

Cholesteryl ester transfer protein (CETP) is a major determinant of the plasma high-density lipoprotein cholesterol (HDL-C) level and plays an important role in the reverse cholesterol transport system. The purpose of this study was to determine the effect of acute hyperinsulinemia on plasma CETP activity in normal subjects and patients with non-insulin-dependent diabetes mellitus (NIDDM). Hyperinsulinemia was achieved using the hyperinsulinemic-euglycemic clamp. CETP activity was determined as the transfer of radiolabeled cholesterol in HDL3 to acceptor lipoprotein. Mean plasma CETP activity during an insulin infusion in both subject groups was significantly decreased compared with the mean basal activity. Suppression of plasma CETP activity in the NIDDM patients was significantly less than in the normal subjects (-4.2% +/- 7.9% v -9.6% +/- 6.4%, P < .02). Regression analysis showed that this suppression was correlated with plasma nonesterified fatty acid (NEFA) levels after the clamp and with the magnitude of the NEFA decrease (r = .318, P < .02 and r = .292, P < .05, respectively). The data suggest that acute hyperinsulinemia reduces plasma CETP activity through a decrease in plasma NEFA.

Renal actinomycosis mimicking renal tumor: case report.

A 68-year-old man was admitted after fever and general fatigue with severe inflammatory signs and anemia. T1- and T2-weighted magnetic resonance imaging showed low- to isointensity and low-intensity tumor in the right kidney, respectively, suggesting renal actinomycosis. However, the right kidney was explored transabdominally because the possibility of renal malignant lymphoma could not be excluded. After nephrectomy, characteristic colonies of Actinomyces were seen microscopically, and the histologic diagnosis was renal actinomycosis. The patient was treated with antibiotics and made good progress after operation. This case highlights the importance of magnetic resonance imaging for the diagnosis of renal actinomycosis.