Comparisons of plasma aldosterone and renin data between an automated chemiluminescent immunoanalyzer and conventional radioimmunoassays in the screening and diagnosis of primary aldosteronism.

Determining values of plasma renin activity (PRA) or plasma active renin concentration (ARC), plasma aldosterone concentration (PAC), and aldosterone-to-renin ratio (ARR) is essential to diagnose primary aldosteronism (PA), but it takes several days with conventional radioimmunoassays (RIAs). Chemiluminescent enzyme immunoassays for PAC and ARC using the Accuraseed® immunoanalyzer facilitated the determination, but relations between Accuraseed® immunoanalyzer-based and RIA-based values in samples of PA confirmatory tests and adrenal venous sampling remained to be elucidated. We addressed this issue in the present study. This is a prospective, cross-sectional study. ARC and PAC values were measured by the Accuraseed® immunoanalyzer in samples, in which PRA and PAC values had been measured by the PRA-FR® RIA and SPAC®-S Aldosterone kits, respectively. The relations between Accuraseed® immunoanalyzer-based and RIA-based values were investigated with regression analyses. The optimal cutoff of Accuraseed® immunoanalyzer-based ARR for PA screening was determined by the receiver operating characteristic analysis. After log-log transformations, linear relations with high coefficients of determination were observed between Accuraseed® immunoanalyzer-based and RIA-based data of renin and aldosterone. Following the PA guidelines of Japan Endocrine Society, Accuraseed® immunoanalyzer-based cutoffs were calculated from the regression equations: the basal PAC for PA screening >12 ng/dL, PAC for the saline infusion test >8.2 ng/dL, ARC for the furosemide-upright test <15 pg/mL, and ARR for the captopril challenge test >3.09 ng/dL per pg/mL. The optimal cutoff of Accuraseed® immunoanalyzer-based ARR for PA screening was >2.43 ng/dL over pg/mL not to overlook bilateral PA patients. The present study provided conversion formulas between Accuraseed® immunoanalyzer-based and RIA-based values of renin, aldosterone, and ARR, not only in basal samples but also in samples of PA confirmatory tests and adrenal venous sampling. Although validation studies are awaited, the present study will become priming water of harmonization of renin and aldosterone immunoassays.

Parameters of captopril challenge test can predict results of other confirmatory tests for primary aldosteronism and propose the next test to be done.

In Japan, primary aldosteronism (PA) is diagnosed if any one of the captopril challenge test (CCT), saline infusion test (SIT), furosemide-upright test (FUP), and oral salt-loading test (OST) is positive. The present study aimed to investigate if parameters of CCT, the safest confirmatory test, could predict decisions of other tests and propose the next test to diagnose PA in CCT-negative patients. In a cross-sectional design, 142 patients, who were referred to our hospital for the scrutiny of PA and underwent at least two confirmatory tests, were enrolled. While 123 patients underwent all of the CCT, SIT, and FUP, the OST was successfully done in only six patients and excluded from further analyses. CCT parameters showing correlations of higher degrees with SIT and FUP parameters were selected, and their powers to predict SIT and FUP decisions were investigated by receiver operating characteristic analyses. Proposals of the next test based on the CCT parameters were validated with SIT and FUP decisions in subsets of CCT-negative patients divided by cut-offs of the CCT parameters. The plasma aldosterone concentration and plasma renin activity 60 min after the load of CCT (CCT60-PAC and CCT60-PRA) were selected, and CCT60-PAC ≤59.0 pg/mL and CCT60-PRA ≥1.05 ng/mL/h could predict negativities of SIT and FUP, respectively, with >95% specificities. Based on the validation, the present study suggested the SIT as the next test to be done if the CCT-negative patient belonged to the subset with CCT60-PAC >59.0 pg/mL and CCT60-PRA ≥1.05 ng/mL/h, otherwise the FUP should be selected.

Thyroid lesions in the great cormorant (Phalacrocorax carbo) of Niigata, central Japan: a possible association with dioxin accumulation.

Necropsy and histopathologic examination of three Great Cormorants (Phalacrocorax carbo) shot in Niigata, central Japan, revealed goitrous changes in the thyroids. Thyroids had a hypertrophic follicular epithelium, loss or deficiency of luminal colloid, occasional small follicles suggesting hyperplasia, and occasional collapsed follicles. Irregularly shaped follicles were frequent, and hyperemia, deposition of dark pigment, and sporadic lymphoid aggregates were also seen. Chemical analysis simultaneously conducted showed higher than normal levels of dioxins in the liver, muscle, and fat, i.e., polychlorinated dibenzo-dioxins, polychlorinated dibenzo-furans, and coplanar polychlorinated biphenyls. The present results, together with those of relevant previous studies, strongly suggest an association between these pollutants and thyroid lesions in the Great Cormorant.

Efficacy and pharmacokinetics of fluvoxamine maleate in patients with mild depression undergoing hemodialysis.

Seven Japanese patients on maintenance hemodialysis who were comorbid with mild depression were medicated with 50 mg/day fluvoxamine maleate for 28 days. Effectiveness was obtained in four out of seven patients (57%). The plasma fluvoxamine concentrations were examined in three patients. The plasma fuvoxamine concentration decreased by 22% by hemodialysis. There is a tendency for the dialyzed rate of fluvoxamine to become lower if the plasma albumin concentration is higher. The half-life of fluvoxamine was possibly shortened more in the patient with hypoalbuminaemia. The plasma fluvoxamine concentration reached a steady state 8 days after the start of medication and thereafter. The time required to reach steady state was lengthened when compared with the results in normal Japanese volunteers.