Osamu Tochikubo

Estimation of 24-h urinary sodium excretion using lean body mass and overnight urine collected by a pipe-sampling method.

Background Although salt intake can be estimated from 24-h urinary sodium excretion (Na24), for a long time there has been no precise and easy method for its measurement. Objective To investigate the possibility of estimating Na24 using pipe-sampling of overnight urine and lean body mass. Participants and methods Body height, body weight and body fat determined by bioelectrical impedance (lean body mass = body weight − body fat) was measured in 351 healthy individuals (126 men, 225 women). Twenty-four-hour urine was collected and creatinine and sodium were measured. To predict 24-h urinary creatinine excretion (Cr24), the relationship between Cr24 and lean body mass was investigated. Both 24-h urine and overnight urine specimens were collected in 149 individuals (71 men, 78 women) using a sampling pipe (semi-automatic proportional urine sampling device; height 16 cm, width 1.5 cm). Multiple regression analysis was used to estimate Na24. Results The prediction of Cr24 (Pr.UCr24) was derived from lean body mass. Using Pr.UCr24 and the overnight urinary Na/Cr excretion ratio (Nan/Crn), Na24 was estimated as 0.634 × (Nan/Crn) × Pr.UCr24 + 104.7 mmol/day for men and 0.682 × (Nan/Crn) × Pr.UCr24 + 62.6 mmol/day for women. The correlation coefficient (r) between true Na24 and Na24 estimated by these formulae was r = 0.78 (P < 0.001; mean difference ± SD–0.03 ± 39.0 mmol/day). Conclusions A new pipe-sampling method using overnight urine and lean body mass was easy and reliable for the estimation of Na24. Furthermore, this method is convenient and may enable counselling on salt intake.

Reliability of resolution of ST-segment elevation after coronary reperfusion in predicting myocardial salvage in anterior wall acute myocardial infarction

Resolution of ST-segment elevation (ST resolution) after reperfusion therapy has been shown to correlate with improved left ventricular (LV) function in patients with acute myocardial infarction (AMI). However, not all patients with ST resolution have preserved LV function. We evaluated the clinical significance of ST resolution in 129 patients with anterior wall AMI who underwent successful coronary recanalization within 6 hours after symptom onset by studying the relation to myocardial blush grade, another angiographic marker of myocardial reperfusion. A reduction of > or =50% in ST-segment elevation after recanalization was defined as ST resolution. Ninety-eight patients had ST resolution and 31 patients did not. Patients with ST resolution were subdivided into 2 groups according to myocardial blush grade after recanalization: 67 patients with blush grade 2 or 3, and 31 with blush grade 0 or 1. The QRS score after recanalization was higher (5.9 +/- 1.9 vs 3.4 +/- 2.0, p <0.01) and predischarge LV ejection fraction was lower (39 +/- 8% vs 57 +/- 9%, p <0.01) in patients with blush grade 0 or 1 than in those with blush grade 2 or 3. However, the QRS score after recanalization and the predischarge LV ejection fraction were similar in patients who had ST resolution with blush grade 0 or 1 and in those without ST resolution. Our findings suggest that ST resolution after recanalization does not consistently predict myocardial salvage in patients with anterior AMI.

Relationship Between Visceral Fat Accumulation and Hypertension in Obese Men

Purpose.u2002Visceral‐fat (VF) accumulation is suggested to be a major contributor to such cardiovascular‐disease risk factors as hypertension (H), glucose intolerance (G), and hyperlipidemia (L). We have devised a simple way of estimating VF accumulation, and investigated the relationship between VF and hypertension in obese men. Methods.u2002First, CT scan was used to measure VF area in the umbilical region in 108 obese men. Then the umbilical‐region circumference (C) was measured with a tape measure and abdominal skinfold thickness (S) with a skinfold caliper. The data obtained with a model formula (VFe = αC2 − βCS + γ) and actual VF area were compared, and three coefficients, α, β, and γ, were calculated by means of multivariate analysis. Next, in 354 male company employees, VFe was estimated using this model formula, and cardiovascular risk factors were investigated. Results.u2002The formula for estimating VF (cm2) was VFe = 0.03C2 − 0.36CS − 47 (correlation coefficient; r = 0.72). Discriminant analysis between the merely obese group (O) and the group complicated by multiple cardiovascular risk factors (O, H, G, and L) determined a VFe‐cutoff value of 120 cm2. Its discriminant sensitivity/specificity values were significantly higher than those based on body mass index (BMI) (cutoff value of 27 kg/m2) (p < 0.05). Hypertensive obese (HO) men with high VFe value (>120 cm2) had a higher frequency of other risk factors (G or L: 86%). Conclusion. VFe is considered useful in estimating VF accumulation, and seems more effective than BMI for predicting multiple cardiovascular risk factors (VF syndrome) in obese hypertensive men.

Relation between C-reactive protein levels on admission and pattern of acute myocardial infarction onset

The pathogenic mechanisms underling the onset of acute myocardial infarction (AMI) have not been fully clarified. Recent observations of inflammatory cell infiltration in unstable coronary plaques suggest that inflammation may play an important role in the pathogenesis of AMI. Plasma levels of C-reactive protein (CRP), a sensitive marker of inflammation, start to rise at least 6 hours after the onset of AMI. Therefore, CRP levels within the first 6 hours after the onset of AMI more likely reflect preexisting inflammatory activity rather than myocardial cell necrosis. We examined the relation between CRP levels on admission and the onset pattern of AMI to estimate the contribution of inflammation to the pathogenesis of AMI.

Factors associated with preventable out-of-hospital nontraumatic cardiac arrest

To identify ways to decrease the risk of out-of-hospital cardiac arrest (CA) caused by an acute coronary syndrome, we examined factors associated with the development of CA > or = 1 hour after symptom onset. Multivariate analysis revealed that a low level of physical activity, a history of diabetes mellitus, and a history of unstable angina are associated with out-of-hospital CA occurring > or = hour after symptom onset.