Senshu Hifumi

Comparison of waist circumference with body mass index for predicting abdominal adipose tissue

AIMS To compare waist circumference (WC) with body mass index (BMI) for the prediction of abdominal adipose tissues in Japanese men and women. METHODS 1432 men and 1038 women aged 38-60 years were recruited. WC, BMI, visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) using CT scans were measured. RESULTS Women had a lower mean VAT than men (79.3 cm(2) vs. 132.3 cm(2); p<0.001) and a higher mean SAT (196.2 cm(2) vs. 139.7 cm(2); p<0.001). The correlation with WC or BMI was greatest for total adipose tissue (TAT), followed by SAT, and least for VAT. The correlation coefficients were not significantly different between WC and BMI for any adipose tissue except for VAT in men (p<0.05). Age was positively correlated with VAT in both genders (p<0.001). Using multiple regression analyses on VAT, R(2) values using WC and age were 0.45 in men and 0.48 in women. For SAT, the values were 0.57 in men and 0.59 in women. CONCLUSIONS The relationship with WC or BMI was greatest for TAT and SAT, and least for VAT. WC and BMI provided essentially similar estimates of TAT, VAT, and SAT in both genders.

Stereoselective pharmacokinetics of amlodipine in elderly hypertensive patients.

Amlodipine is a dihydropyridine calcium antagonist and is widely used for the treatment of cardiovascular diseases. Amlodipine has two stereoisomers [R(+), S(−)], and only the S(−) isomer exerts vasodilating action. In this preliminary study, amlodipine (5 mg) was given to three elderly hypertensive patients once daily for 10 days. Blood samples were obtained, and serum concentrations of R(+)- and S(−)-amlodipine were measured by a gas chromatographic method. The R(+)/S(−) ratio of plasma amlodipine in these elderly subjects was greater than that reported in young subjects. These results suggest that the influence of aging on the pharmacokinetic profiles might differ between the R(+)- and S(−)-isomers of amlodipine.

The role of prostaglandins for norepinephrine clearance in borderline hypertension

Studies were done to determine the role of endogenous prostaglandins (PGs) for norepinephrine (NE) clearance in 10 male borderline hypertensives (BHT) (age: 20-28) and six age-matched male normotensives (NT). Two experimental protocols were followed in these subjects: 10 min orthostasis with blood sampling (protocol I), and 100 ng/kg/min of L-NE infusion for 60 min at supine position. Blood was collected from indwelling catheter at every min for 10 min after stopping the NE infusion (protocol II). Plasma NE was measured by THI method using HPLC. Disappearance curve of plasma NE was analyzed following the two compartment open model. The orthostasis and the steady state NE infusion were repeated after 150 mg/day of indomethacin (Ind) for three days. There were significant increases in plasma NE after orthostasis in both groups: from 180.8 +/- 28.0 pg/ml to 346.2 +/- 78.0 pg/ml (p less than 0.05) in NT and from 120.1 +/- 12.8 pg/ml to 289.6 +/- 20.3 pg/ml (p less than 0.001) in BHT, but there were no significant differences between the two groups. Ind pretreatment did not alter these responses. The calculated half-time of the first exponential phase (T 1/2) was 1.50 +/- 0.07 min in NT which decreased to 0.98 +/- 0.10 min (p less than 0.05) after Ind pretreatment. In BHT, T 1/2 was 1.03 +/- 0.08 min (p less than 0.01 vs NT), which was not significantly changed after Ind. These results may suggest that endogenous PGs have some role(s) in NT for NE clearance, probably exerting inhibitory action on neuronal uptake. In BHT, neuronal uptake of NE is increased, probably due to an adaptation mechanism to elevated blood pressure.