Kazushige Iinuma

Acute Jaundice in Vientiane, Lao People's Democratic Republic

Analysis of serum samples from patients with acute jaundice by means of enzyme-linked immunosorbent assay and polymerase chain reaction testing provided the first profile of this condition in Vientiane, Lao PDR, in 1995 and 1996. In a case-control, hospital-based study, evidence of acute infections due to hepatitis A and B viruses was found in 14% and 10% of cases, respectively. Hepatitis E virus, however, did not appear to contribute to clinically recognized acute jaundice. Similarly, antibody to hepatitis C virus was recognized in almost equal proportions of cases (8%) and controls (6%), thus representing probable background infections. The detection of hepatitis G virus marks the first report of this virus in Lao PDR. The large proportion (21%) of new leptospiral infections in cases without acute hepatitis A or B was notable. This finding suggests significant regional underreporting of leptospirosis as a cause of acute jaundice. The limited laboratory diagnostic capabilities for confirming a differential diagnosis of leptospirosis contribute to the lack of attention paid to this important health problem.

Hemodynamic, renal, and hormonal responses to alpha‐human atrial natriuretic peptide in patients with congestive heart failure

Hemodynamic, renal, and hormonal effects of intravenous bolus injection of 50 µg synthetic α‐human atrial natriuretic peptide (α‐hANP) were studied in eight patients with congestive heart failure. α‐hANP caused significant reductions in mean blood pressure and systemic vascular resistance. These responses were sustained up to 90 minutes and not accompanied by reflex tachycardia. Cardiac index and stroke volume index increased significantly at 90 minutes and pulmonary capillary wedge pressure, pulmonary arterial pressure, and mean right atrial pressure remained unchanged. Urine volume, urinary sodium excretion, creatinine clearance, and fractional excretion of sodium increased significantly, but fractional excretion of potassium and phosphate did not change. Elevated plasma renin activity, plasma aldosterone, and norepinephrine were suppressed after the injection of α‐hANP. The bolus injection of this peptide has moderately hypotensive, vasorelaxant, and natriuretic effects in patients with congestive heart failure.

Changes in the plasma hANP level during long-term salt loading in patients with essential hypertension

Serial changes in the plasma hANP (human atrial natriuretic peptide) level in patients with essential hypertension were determined during high salt intake for two weeks after salt restriction for 5 days. The mean plasma hANP level decreased during salt depletion for 5 days from 60 +/- 10 pg/ml to 39 +/- 8 pg/ml. During high salt intake (20 g NaCl/day) for two weeks, the plasma hANP level increased gradually to a maximum of 71 +/- 16 pg/ml on day 7 and then decreased to 54 +/- 9 pg/ml on day 14. The plasma levels of renin activity, aldosterone and noradrenaline decreased during salt repletion. Changes in the plasma hANP level were correlated positively with those of urinary sodium excretion and negatively with those of plasma renin activity on days 7 and 14 of salt repletion. Change in the plasma hANP level correlated with that in the mean blood pressure on day 14, but not day 7 of salt repletion. These findings indicate that the plasma hANP level is closely related to sodium intake in patients with essential hypertension.

A simplified Radioimmunoassay for serum aldosterone

: A simplified direct radioimmunoassay system for serum aldosterone measurement was developed by using radio iodine-labeled aldosterone and highly specific antiserum to aldosterone. 8-anilino-1-naphthalene sulfonic acid(ANS) was used to prevent the binding of aldosterone to serum proteins. Polyethylene glycol was used to separate the antibody-bound aldosterone from the free aldosterone as the precipitant. The minimum measurable concentration of aldosterone is 30pg/ml of serum by short incubation method (at 25 degrees C for 3hr incubation) and 15pg/ml of serum by long incubation method (at 4 degrees C for 20 hr incubation) respectively. Present radioimmunoassay eliminates extraction of the aldosterone from serum and chromatographic separation procedures, and requires only 0.1ml of serum sample for assay. The intra-assay precision was C. V. 6.9% (average of 4 samples) and the inter-assay precision was C. V. 10.7% (average of 4 samples). There is an excellent correlation between the extraction method and this direct method in serum aldosterone value obtained (correlation coefficient, 0.96). The normal value was 36.8+/-25.9pg/ml (recumbent) and 113.6+/-6.15pg/ml (upright).

A simple method measuring plasma aldosterone by radioimmunoassay without extraction

: A radioimmunoassay method was developed to measure plasma aldosterone levels. Antibody was produced in rabbits by injecting aldosterone oxime coupled with bovine gamma-globulin once a month. Plasma aldosterone was measured simultaneously by two methods: the direct method without extraction and a method using paper chromatography. 125I-aldosterone was used in the first method and 3H-aldosterone in the second. The antibody had a high specificity adequate to show zero water blank in the first method. Adequate precision, accuracy and sensitivity were obtained in a direct method using 125I-aldosterone. Plasma aldosterone levels were 7.1+/-3.0ng/100ml (Mean +/-SD) in normal subjects and slightly higher after injecting ACTH-Z. The correlative coefficient between the first and the second method was significantly high (r=0.970, P less than 0.001, n=37). Plasma aldosterone was high (34.3+/-14.1ng/100ml, n=7) in primary aldosteronism, slightly high (14.2+/-2.6ng/100ml) in secondary aldosteronism, normal in Cushings syndrome (10ng/100ml) and low in Addisons disease (1ng/100ml), hypopituitarism (1ng/100ml) and pseudoaldosteronism (2ng/100ml). From these results, it is concluded that the direct method without extraction was a very useful and reliable method for measuring plasma aldosterone. It was superior in simplicity and there is no need to use a liquid scintillation counter.

A Simplified Direct Radioimmunoassay for Urinary Aldosterone

A simplified direct radioimmunoassay for urinary acid labile aldosterone was developed. One ml of urine was hydrolysed with 2 ml of 0.2N HCL at 30 degrees C for 16hrs. One tenth ml of hydrolysed urine diluted 10 times with charcoal treated aldosterone-free calf serum was used for the radioimmunoassay. The radioimmunoasssay was done with a specific antibody, 125I-aldosterone, as the labeled antigen and polyethylene glycol for bound-free separation. There were excellent correlations between the present methods and other methods, i.e., i) a method using dichloromethane extraction before the assay as well as pre-extraction before hydrolysis and ii) a commercial kit using 3H-aldosterone. The intra-assay coefficient of variation was 5.8%, and the inter-assay coefficient of variation was 9.5%. The normal value of urinary aldosterone was excretion was 3.7 plus or minus 2.5 micrograms/day by the present method, and values of patients with primary aldosteronism were between 24 to 43 micrograms/day.

A simple and direct radioimmunoassay for serum and urinary metanephrine

A simple, direct and specific radioimmunoassay for serum and urinary metanephrine was developed, in which we used 125I-Synephrine and specific antiserum generated in rabbits by injecting with metanephrine conjugated with bovine serum albumin as described by Grota and Brown. The sensitivity of the assay was 2 pg/tube. Intra- and inter-assay coefficients of variation were 2.6 approximately 7.8% and 5.0 approximately 9.6%, respectively. The recoveries of metanephrine added at two levels of 250 pg/ml and 500 pg/ml to ten serum samples and ten urine samples (hydrolyzed and diluted) were 96.7 and 108% in serum, and 94.8 and 103% in urine, respectively. Normal values of serum metanephrine were 40.3 +/- 25.8 pg/ml (mean +/- SD) from 20 normal subjects. Normal values of 24 hour urinary metanephrine excretion were 12.5 +/- 6.7 ug/day from 24 normal subjects. Serum metanephrine values for 7 patients with pheochromocytoma were 210 approximately 628 pg/ml. Urinary metanephrine values for 9 patients with pheochromocytoma 8.7 approximately 302 ug/day.