A case report on intravascular lithotripsy to facilitate retrograde wire passage from the subintimal to the luminal space in a calcified chronic total occlusion

Background

Severe calcifications are a major reason for failures in chronic total coronary occlusions, as they can obstruct the wire passage both in the antegrade and retrograde technique.

Case summary

The proximal occlusion of the left anterior descending artery in a 75-year-old man presented with a completely concentric calcified ring all along the segment proximal to the occlusion. The antegrade wire could not pass the calcified occlusion, and in a retrograde approach via the right posterior descending artery the retrograde wire was not able to enter the lumen from a subintimal position outside of the calcified ring. Intravascular lithoplasty in the proximal segment led to a crack in this ring to enable the same retrograde wire now to pass into the true lumen with then successful conclusion of the case. Intravascular ultrasound demonstrated the modification of the calcified ring and the passage of the wire with only a very short subintimal pathway.

Discussion

Intravascular lithoplasty is a new option to modify severely calcified vessel segments to facilitate the reverse controlled antegrade and retrograde tracking approach. In the present case, this helped to avoid a long subintimal pathway and preserved the vessel anatomy.

Prognostic Impact of Renal Function on 5-Year Outcomes After Fractional Flow Reserve-Guided Deferral of Revascularization

Background Chronic kidney disease (CKD) might influence fractional flow reserve (FFR) value, potentially attenuating its prognostic utility. However, few large-scale data are available regarding clinical outcomes after FFR-guided deferral of revascularization in patients with CKD. Methods and Results From the J-CONFIRM registry (Long-Term Outcomes of Japanese Patients With Deferral of Coronary Intervention Based on Fractional Flow Reserve in Multicenter Registry), 1218 patients were divided into 3 groups according to renal function: (1) non-CKD (estimated glomerular filtration rate ≥60 mL/min per 1.73 m2), n=385; (2) CKD (estimated glomerular filtration rate 15-59 mL/min per 1.73 m2, n=763); and (3) end-stage renal disease (ESRD) (eGFR <15 mL/min per 1.73 m2, n=70). The primary study end point was the cumulative 5-year incidence of target vessel failure (TVF), defined as a composite of cardiac death, target vessel myocardial infarction, and clinical driven target vessel revascularization. Cumulative 5-year incidence of TVF was significantly higher in the ESRD group than in the CKD and non-CKD group, whereas it did not differ between the CKD and non-CKD groups (26.3% versus 11.9% versus 9.5%, P<0.001). Although the 5-year TVF risk increased as the FFR value decreased regardless of renal function, patients with ESRD had a remarkably higher risk of TVF at every FFR value than those with CKD and non-CKD. Conclusions At 5 years, patients with ESRD showed a higher incidence of TVF than patients with CKD and non-CKD, although with similar outcomes between patients with CKD and non-CKD. Patients with ESRD had an excess risk of 5-year TVF at every FFR value compared with those with CKD and non-CKD. Registration URL: https://www.umin.ac.jp; Unique identifier: UMIN000014473.

Objective Evaluation With Noncontrast Computed Tomography Can Reveal Calcified Plaque Solidity in Peripheral Artery Diseases

PURPOSE

The presence of severely calcified plaque remains problematic in endovascular therapy, and no specific endovascular treatment strategy has been established. Estimating plaque solidity before the procedure may help operators penetrate calcified plaque with a guide wire. The aim of this study was to establish a method of measuring plaque solidity with noncontrast computed tomography (CT).

METHODS

This retrospective, single-center study included consecutive patients who, between October 2020 and July 2022, underwent noncontrast 5 mm and 1 mm CTs before endovascular therapy to penetrate calcified plaque with a wire in the common femoral, superficial femoral, and popliteal arteries. Three cross-sectional CT slices were selected. To target a calcified plaque lesion, the operator identified a region of interest, which corresponded to 24×24 pixels, and Hounsfield unit (HU) values of each pixel were displayed on the CT image. The average HU values and the ratio of number of pixels of lower values (130-599 HU) represented plaque solidity. We used the Mann-Whitney-Wilcoxon rank-sum test and the chi-square test to compare the solidity of plaques penetrated and not penetrated by the wire.

RESULTS

We evaluated 108 images of 36 calcified plaque lesions (in 19 patients). The wire penetrated 28 lesions (77.8%) successfully. The average HU value was significantly lower in the lesions that the wire penetrated than in the others, in both the 5 mm CT slices (434.7±86.8 HU vs 554.3±112.7 HU, p=0.0174) and 1 mm slices (497.8±103.1 HU vs 593.5±114.5 HU, p=0.0381). The receiver operating curve revealed that 529.9 and 533.9 HU in the 5 and 1 mm slices, respectively, were the highest values at which wires could penetrate. Moreover, at the lesions that were penetrates successfully, the ratio of number of lower HU value pixels was significantly higher both in 5 mm slice CTs (74.7±13.4 vs 61.7±13.1%, p=0.0347) and 1 mm (68.7±11.8 vs 57.1±11.4%, p=0.0174).

CONCLUSION

The use of noncontrast CT to evaluate plaque solidity was associated with successful wire penetration of calcified lesions in peripheral arteries.

CLINICAL IMPACT

This study revealed an association between the wire penetration inside calcified plaque and plaque solidity estimated using non-contrasted computed tomography. The mean Hounsfield unit values of three cross-sections in calcified plaques were associated with the successful wire penetration. This wire penetration difficulty is associated with extended procedure time, excessive radiation exposure, usage of extra contrast agents, and increased medical costs. Therefore, estimating calcified plaque solidity before procedure enables us to choose effective and lean procedures. In addition, to predict the success of dilating calcified plaque from the inside is also beneficial when the operator wants to avoid extra scaffold implantation for target lesions.

Impact of bystander cardiopulmonary resuscitation on neurological outcomes in patients undergoing veno-arterial extracorporeal membrane oxygenation

BACKGROUND

Veno-arterial extracorporeal membrane oxygenation (V-A ECMO) requires a large amount of economic and human resources. The presence of bystander cardiopulmonary resuscitation (CPR) was focused on selecting appropriate V-A ECMO candidates.

RESULT

This study retrospectively enrolled 39 patients with V-A ECMO due to out-of-hospital cardiac arrest (CA) between January 2010 and March 2019. The introduction criteria of V-A ECMO included the following: (1) < 75 years old, (2) CA on arrival, (3) < 40 min from CA to hospital arrival, (4) shockable rhythm, and (5) good activity of daily living (ADL). The prescribed introduction criteria were not met by 14 patients, but they were introduced to V-A ECMO at the discretion of their attending physicians and were also included in the analysis. Neurological prognosis at discharge was defined using The Glasgow-Pittsburgh Cerebral Performance and Overall Performance Categories of Brain Function (CPC). Patients were divided into good or poor neurological prognosis (CPC ≤ 2 or ≥ 3) groups (8 vs. 31 patients). The good prognosis group had a significantly larger number of patients who received bystander CPR (p = 0.04). The mean CPC at discharge was compared based on the combination with the presence of bystander CPR and all five original criteria. Patients who received bystander CPR and met all original five criteria showed significantly better CPC than patients who did not receive bystander CPR and did not meet some of the original five criteria (p = 0.046).

CONCLUSION

Considering the presence of bystander CPR help in selecting the appropriate candidate of V-A ECMO among out-of-hospital CA cases.

Association of guideline-directed medical therapy adherence with outcomes after fractional flow reserve-based deferral of revascularization

AIMS

Guideline-directed medical therapy (GDMT) is essential to prevent future cardiovascular events in chronic coronary syndrome (CCS) patients. However, whether achieving optimal GDMT could improve clinical outcomes in CCS patients with deferred lesions based on fraction flow reserve (FFR) remains thoroughly investigated. We sought to evaluate the association of GDMT adherence with long-term outcomes after FFR-based deferral of revascularization in a real-world registry.

METHODS AND RESULTS

This is a post-hoc analysis of the J-CONFIRM registry (long-term outcomes of Japanese patients with deferral of coronary intervention based on fractional flow reserve in multicentre registry). Optimal GDMT was defined as combining four types of medications: antiplatelet drug, angiotensin-converting enzyme inhibitor/angiotensin II receptor blocker, beta-blocker, and statin. After stratifying patients by the number of individual GDMT agents at 2 years, landmark analysis was conducted to assess the relationship between GDMT adherence at 2 years and 5-year major adverse cardiac events (MACEs), defined as a composite of all-cause death, target vessel-related myocardial infarction, clinically driven target vessel revascularization. Compared with the suboptimal GDMT group (continuing ≤3 types of medications, n = 974), the optimal GDMT group (n = 139) showed a lower 5-year incidence of MACE (5.2% vs. 12.4%, P = 0.02). The optimal GDMT was associated with a lower risk of MACE (hazard ratio: 0.41; 95% confidence interval: 0.18 to 0.92; P = 0.03).

CONCLUSION

Patients with optimal GDMT were associated with better outcomes, suggesting the importance of achieving optimal GDMT on long-term prognosis in CCS patients after FFR-guided deferral of revascularization.

Thrombotic Risk and Cardiovascular Events in Patients With Revascularization Deferral After Fractional Flow Reserve Assessment

OBJECTIVES

The aim of this study was to evaluate the impact of thrombotic risk on the occurrence of cardiovascular events in patients with coronary artery disease with deferred revascularization after fractional flow reserve (FFR) measurements.

BACKGROUND

Deferral of revascularization on the basis of FFR is generally considered to be safe, but after deferral, some patients have cardiovascular events over time.

METHODS

From J-CONFIRM registry (Long-Term Outcomes of Japanese Patients With Deferral of Coronary Intervention Based on Fractional Flow Reserve in Multicenter Registry), 1,263 patients with deferral of revascularization on the basis of FFR were evaluated. The association between thrombotic risk as assessed by CREDO-Kyoto (Coronary Revascularization Demonstrating Outcome Study in Kyoto) thrombotic score and 5-year target vessel failure (TVF) and major adverse cardiac and cerebrovascular events (MACCE) was investigated.

RESULTS

FFR and high thrombotic risk (HTR) were associated with increased risk for 5-year TVF (FFR per 0.01-unit decrease: HR: 1.08; 95% CI: 1.05-1.11; P < 0.001; HTR: HR: 2.16; 95% CI: 1.37-3.39; P < 0.001) and MACCE (FFR per 0.01-unit decrease: HR: 1.05; 95% CI: 1.02-1.06; P < 0.001; HTR: HR: 2.11; 95% CI: 1.56-2.84; P = 0.001). Patients with HTR had higher risk for 5-year TVF (HR: 2.30; 95% CI: 1.45-3.66; P < 0.001) and MACCE (HR: 2.34; 95% CI: 1.75-3.13; P < 0.001) than those without HTR, even when they had negative FFR.

CONCLUSIONS

Assessment of thrombotic risk provides additional prognostic value to FFR in predicting 5-year TVF and MACCE in patients with deferral of revascularization after FFR measurements. (Long-Term Outcomes of Japanese Patients With Deferral of Coronary Intervention Based on Fractional Flow Reserve in Multicenter Registry; UMIN000014473).

Five-Year Outcomes After Fractional Flow Reserve-Based Deferral of Revascularization in Chronic Coronary Syndrome: Final Results From the J-CONFIRM Registry

BACKGROUND

Little large-scale data is available about the long-term (beyond 3 years) clinical outcomes after fractional flow reserve (FFR)-based deferral of revascularization in clinical practice. We sought to assess the 5-year outcomes after deferral of revascularization based on FFR.

METHODS

The J-CONFIRM registry (Long-Term Outcomes of Japanese Patients With Deferral of Coronary Intervention Based on Fractional Flow Reserve in Multicenter Registry) prospectively enrolled 1263 patients with 1447 lesions in whom revascularization was deferred based on FFR from 28 Japanese centers. The primary study end point was the cumulative 5-year incidence of target vessel failure (TVF), including cardiac death, target vessel-related myocardial infarction, and clinically driven target vessel revascularization.

RESULTS

Five-year follow-up was completed in 92.2% of patients. The 5-year TVF rate was 11.6% in deferred lesions, mainly driven by clinically driven target vessel revascularization (9.8%). Cardiac death and target vessel-related myocardial infarction were 1.9% and 0.95%, respectively. Cumulative 5-year incidence of TVF was similar between the FFR 0.75 to 0.80 and 0.81 to 0.85 groups even after adjustment for baseline characteristics (12.2% versus 13.0%, inverse probability-weighted hazard ratio, 0.86 [95% CI, 0.46-1.60]; P=0.63). Compared with the almost normal FFR (0.86-1.00) group, the significant (<0.75) and borderline (0.75-0.85) FFR groups showed a higher incidence of TVF at 5 years (29.9% versus 12.8% versus 8.6%, P<0.001). Independent predictors of the 5-year TVF were hemodialysis, FFR value, left main coronary artery lesion, prior percutaneous coronary intervention, and male sex.

CONCLUSIONS

The 5-year TVF rate was 11.6% in deferred lesions, mainly driven by clinically driven target vessel revascularization. Notably, cardiac death and target vessel-related myocardial infarction rarely occurred during the follow-up. Our findings highlight the long-term safety of FFR-based deferral of revascularization in patients with chronic coronary syndrome. Registration: URL: https://www.umin.ac.jp/ctr; Unique identifier: UMIN000014473.

A Case of ST-Elevation Acute Myocardial Infarction in a Nonhospitalized Patient with SARS-CoV-2 Pneumonia: Treatment with Primary Percutaneous Coronary Intervention

We experienced a case of primary percutaneous coronary intervention for ST-elevation myocardial infarction (STEMI) with coronavirus disease 2019 (COVID-19) using appropriate infection prevention protocol. However, recanalization was difficult due to severe coagulopathy. Further researches are needed to clarify optimal treatment for STEMI in patients with COVID-19.

A prospective study on the incidence of contrast-associated acute kidney injury after recanalization of chronic total coronary occlusions with contemporary interventional techniques

BACKGROUND

Contrast-associated acute kidney injury (CA-AKI) is a potential risk associated with the percutaneous coronary interventions (PCI) for chronic total coronary occlusions (CTO). This study should evaluate the incidence of CA-AKI in an era of advanced strategies of recanalization techniques and identify modifiable determinants.

METHODS

We analysed 1924 consecutive CTO procedures in 1815 patients between 2012 and 2019. All patients were carefully monitored at least up to 48 h after a CTO procedure for changes in renal function.

RESULTS

The incidence of CA-AKI was 5.6%, but there was no relation to the technical approach such as frequency of the retrograde technique, intravascular ultrasound or radial access. Procedures with CA-AKI had longer fluoroscopy times (37.6 vs 46.1 min; p = 0.005). The major determinants of CA-AKI were age, presence of diabetes and reduced ejection fraction, as well as chronic kidney disease stage ≥2, serum haemoglobin, and fluoroscopy time. Contrast volume or contrast volume/GFR ratio were not independent determinants of CA-AKI. Periprocedural perforations were more frequent in CA-AKI patients (11.3 vs 2.3%; p < 0.001), and in-hospital mortality was higher (2.8 vs 0.4%; p < 0.001).

CONCLUSIONS

CA-AKI was associated with the risk of in-hospital adverse events. Established patient-related risk factors for CA-AKI (age, diabetes, preexisting chronic kidney disease, low ejection fraction) were confirmed in this study. In addition, the length of the procedure, coronary perforations and low preprocedural serum haemoglobin were risk factors that might be preventable in patients at high risk for CA-AKI.

Reducing fluoroscopic and cineangiographic contribution to radiation exposure for chronic total coronary occlusion interventions

BACKGROUND

The treatment of chronic total coronary occlusions (CTO) carries the highest radiation exposure among percutaneous coronary interventions (PCI). In order to minimize radiation damage, we need to understand and optimize the contribution of all components of radiation exposure.

METHODS

A total of 1000 CTO procedures performed between 2011 and 2020 were compared according to implemented radiation modifications. Group 1 used the original set-up of the X-ray equipment (Artis Zee, Siemens). In group 2 a modified protocol aimed at reducing the fluoroscopy exposure, in group 3 further modifications aimed at reducing cineangiographic exposure.

RESULTS

Despite an increased lesion complexity, Air Kerma (AK) was reduced from 2619 mGy (1653-4574) in group 1 to 2178 mGy (1332-3500; p < 0.001) in group 2 by mainly reducing fluoroscopic contribution by 54.1%, the cineangiographic contribution was lowered by only 6.6%. In group 3 AK dropped drastically to 746 mGy (480-1225; p < 0.001) mainly by reducing the cineangiographic contribution by 53.4%, still there was a further reduction of fluoroscopy contribution of 8.2%. This also led to a reduction of the skin entry dose from 1038 mGy (690-1589) in group 2 to 359 mGy (204-591; p < 0.001) in group 3. This was achieved both in normal weight and obese patients, and both in antegrade and retrograde procedures.

CONCLUSIONS

The present study demonstrates that by modifying both the fluoroscopic and cineangiographic contribution to radiation exposure a drastic reduction of radiation risk can be achieved, even in obese patients. Currently accepted radiation thresholds may no longer be a limit for CTO PCI.

Serum cytokine profiling in neonates with hypoxic ischemic encephalopathy

BACKGROUND

The fetal brain is vulnerable to severe and sustained hypoxia during and after birth, which can lead to hypoxic-ischemic encephalopathy (HIE). HIE is characterized by clinical and laboratory evidence of acute or subacute brain injury. The role of cytokines in the pathogenesis of brain injury and their relation to neurological outcomes of asphyxiated neonates are not fully understood. In this study, we investigated cytokine profile related to cerebral palsy (CP) with neonatal hypoxic ischemic encephalopathy (HIE) and HIE severity.

METHODS

Eligible subjects were HIE newborns with a gestational age between 36 and 42 weeks. We included newborns who was born at our NICU and did not admit to NICU as healthy controls. The study comprised 52 newborns, including 13 with mild to severe HIE and 39 healthy control. Serum cytokine profiles were performed using a LUMINEX cytokine kit (R&D Systems).

RESULTS

VEGF, MCP-1, IL-15, IL-12p70, IL-12p40, IL-1Ra, IL-2, IL-6, IL-7, IL-8, IL-10, IFN-γ, G-CSF and eotaxin in the HIE patients were significantly increased compared with the healthy neonates. In the subgroup analysis, IL-6 and G-CSF were significantly increased in CP infants (n = 5) compared with non-CP infants (n = 8). Five and eight HIE patients were classified into the mild HIE and moderate-severe HIE groups, respectively. IL-6, 10, 1Ra, and G-CSF in the moderate-severe HIE group were significantly higher than those in the mild HIE group.

CONCLUSION

We demonstrated that higher serum IL-6 and G-CSF at birth in HIE patients were associated with CP and moderate-severe HIE.

Resolving chronic stent under-expansion in calcified lesions by intravascular lithoplasty

Severe coronary calcification is a common cause for stent under-expansion, which is associated with an increased risk of stent thrombosis and restenosis. Presently the devices for treatment of under-expanded stent due to severe calcification are rotational atherectomy and high-pressure non-compliant balloons with the limitation of potential balloon rupture and perforation risk. We report on a series of seven successful treatments of chronically under-expanded stents due to severe calcification using shockwave coronary intravascular lithoplasty (IVL). Our report suggests that IVL is a feasible and safe tool for such chronically under-expanded stents. <Learning objective: Severe coronary calcification is a common cause for stent under-expansion, which is associated with an increased risk of stent thrombosis and restenosis. Presently the devices for treatment of under-expanded stent due to severe calcification are rotational atherectomy and high-pressure non-compliant balloons. Our report suggests that intravascular lithoplasty is a feasible and safe tool to expand chronically under-expanded stents due to severe calcification, and that it is superior to rotational atherectomy and high-pressure balloons.>.

Association between cognitive impairment patient with solid cancer and insulin resistance

Objectives

In an aging population, an increase in the number of elderly cancer patients with cognitive impairment is expected. The possible association between cancer and cognitive impairment is important to elucidate, because it can have a serious impact on quality of life. Here, we focused on glucose metabolism as a factor that links cancer and cognitive impairment.

Results

Thirteen subjects with solid cancers and cognitive impairment were recruited. As a control group, 14 subjects with cognitive impairment alone and 8 subjects with cancer alone were recruited. A Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) and that of β-cell function (HOMA-B) were used. In comparison with patients with solid cancer alone, those with cognitive impairment alone and those with both cancer and cognitive impairment had increased HOMA-IR values. Insulin resistance was increased in patients with cognitive impairment alone and those with both cognitive impairment and solid cancer than in patients without cognitive impairment; however, β-cell function was not affected. The present data indicated that elderly cancer patients with high HOMA-IR score may be at a relatively high risk for developing cognitive impairment. Furthermore, early treatment to reduce insulin sensitivity may prevent cognitive impairment.

Abstract 294: Decreased Plasma Omega-3 to Omega-6 Polyunsaturated Fatty Acid Ratio Associated with Apical Ballooning Syndrome (Tako-Tsubo cardiomyopathy -TTC)

Background: Eicosapentaenoic acid (EPA) of the omega-3 polyunsaturated fatty acids (ω-3 PUFA) family plays important roles in the prevention of cardiovascular disease, while, arachidonic acid (AA) of the ω-6 PUFA family promotes inflammatory and prothrombotic influences. Tako-Tsubo cardiomyopathy (TTC) is a heart syndrome associated with transient myocardial contractile dysfunction. Decreased endothelial function in response to acute mental stress has been reported in patients with a prior episode of TTC. However, the pathogenesis of TTC remains unclear and the relationship between TTC and EPA/AA ratio has not been elucidated.

Methods and Results: This study consisted of 10 consecutive patients with clinically diagnosed TTC. The aim of this study was to investigate the association between the plasma EPA/AA ratio and the early stage of clinically diagnosed TTC. To examine the plasma fatty acid level, blood samples were obtained from control, old myocardial infarction, and clinically diagnosed TTC patients. A clinically diagnosed TTC patients revealed a lower plasma EPA/AA ratio [Control patients, 0.58 (n=18) vs OMI patients, 0.38 (n=22) vs TTC patients, 0.12 (n=10), p=0.011]. High-sensitivity CRP levels and a low plasma EPA/AA ratio could independently predict the prevalence of TTC on multivariate logistic regression analysis [odds ratio 1.83 (95%CI 1.03-3.25), p=0.036 and odds ratio 2.05 (95%CI 1.12-3.92), p=0.02)].

Conclusion: In patients with TTC, a low plasma EPA/AA ratio was significantly associated with the early stage of clinically diagnosed TTC. The findings implicate lower EPA/AA ratio and the following endothelial dysfunction as a potential mechanism involved in the pathogenesis of this unique cardiomyopathy.

Propensity score analysis of 10-year long-term outcome after bypass surgery or plain old balloon angioplasty in patients with metabolic syndrome

Clinical hard outcomes (death and myocardial infarction) between bypass surgery (CABG) and percutaneous coronary intervention (PCI) are generally similar, whereas target vessel revascularization and angina relief are often superior with CABG. However, there are no data regarding 10-year long-term clinical outcomes between the two procedures in metabolic syndrome (MetS). The aim of this study was to assess the long-term outcomes of CABG and plain old balloon angioplasty (POBA) in MetS patients. We enrolled 869 patients, 318 (36.6%) and 551 (63.4%) of whom underwent POBA and CABG, respectively. During follow-up (10.1 ± 3.5 years), 221 patients died (118 cardiovascular deaths) and 256 underwent revascularization. We predicted the probability of undergoing CABG using propensity analysis. Unadjusted survival was significantly lower in the CABG group because of unfavorable baseline characteristics. After adjusting for baseline variables including propensity score, POBA and CABG did not differ in terms of all cause (hazard ratio [HR] of CABG, 1.46; P = 0.132) and cardiovascular mortality (HR of CABG, 1.11; P = 0.757). However, the risk of subsequent revascularization was significantly lower in the CABG group than in the POBA group (HR of CABG, 0.15; P < 0.001). This study demonstrated that CABG is superior to POBA in terms of target vessel revascularization in MetS patients, whereas there were no significant differences in mortality after adjusting for baseline variables including propensity score.

Increased circulating plasma lysophosphatidic acid in patients with acute coronary syndrome

BACKGROUND

The platelet activator lysophosphatidic acid (LPA) has recently been identified as an ingredient in oxidized LDL and it has been isolated from atherosclerotic plaques. The lysophospholipase D activity of autotaxin produces LPA extracellularly from lysophosphatidylcholine (LPC). The present study determines whether circulating LPA is associated with acute coronary syndrome (ACS).

METHODS

We enrolled 141 consecutive patients (age, 62.6±3.8 y; male, 69.2%) with ACS (n=38), stable angina pectoris (SAP; n=72) or angiographically normal coronary arteries (NCA; n=31). The relationships between LPA and other established biomarkers were examined. Concentrations of plasma LPA were determined using an enzymatic assay.

RESULTS

Concentrations of LPA significantly correlated with LPC (r=0.549), autotaxin (r=0.370) and LDL-C (r=0.307) (all p<0.01). Lysophosphatidic acid concentrations were significantly higher in patients with ACS than with SAP and NCA (p<0.01), but did not significantly differ between patients with SAP and NCA. Multivariate logistic regression analyses revealed that the highest LPA tertile was independently associated with ACS (odds ratio 1.99, 95% CI: 1.18-3.39, p=0.02).

CONCLUSIONS

The present study demonstrated that increased circulating plasma LPA concentrations are significantly associated with ACS.

Infective endocarditis with Lactococcus garvieae in Japan: a case report

Introduction

Lactococcus garvieae is a well-recognized fish pathogen, and it is considered a rare pathogen with low virulence in human infection. We describe the 11th case of L. garvieae infective endocarditis reported in the literature, and the first reported case in Japan.

Case presentation

We report a case of a 55-year-old Japanese woman who had native valve endocarditis with L. garvieae. The case was complicated by renal infarction, cerebral infarction, and mycotic aneurysms. After anti-microbial treatment, she was discharged from the hospital and is now well while being monitored in the out-patient clinic.

Conclusion

We encountered a case of L. garvieae endocarditis that occurred in a native valve of a healthy woman. The 16S ribosomal RNA gene sequencing was useful for the identification of this pathogen. Although infective endocarditis with L. garvieae is uncommon, it is possible to treat high virulence clinically.

Catheter Ablation of Tachycardias After Undergoing a Surgical Atriotomy Using a Multipolar Electrode Catheter

BACKGROUND

A variety of supraventricular tachyarrhythmias may occur in patients after undergoing a surgical atriotomy. The purpose of this study was to characterize them and determine the role of conventional mapping.

METHODS AND RESULTS

In 45 patients after a surgical atriotomy, 68 atrial tachyarrhythmias were observed. A conventional mapping system with a 20-pole electrode catheter used in the electrophysiological study detected 39 atrial tachycardias (ATs). Type 1 atrial flutter (AFL) was observed in 23 and reverse type 1 AFL in 4. AT was classified into 3 subgroups, namely, incisional macroreentrant AT (n=31), incisional focal AT (n=1) and non-incisional AT (n=7). In the patients with incisional macroreentrant AT after the standard right atriotomy, the 20-pole electrode catheter placed on the incision could easily record the entire sequence of the atrial activation. Successful catheter ablation was achieved in all patients with incisional reentrant AT. The ablation site of incisional reentrant AT was the isthmus between the incision and the superior vena cava cannulation scar in 4, between the incision and the inferior vena cava cannulation scar in 22, and the area at the septal incision in 3. The remaining 2 incisional ATs were left atrial AT and right atrial transincisional AT.

CONCLUSIONS

The conventional mapping system is still very useful for making an electrophysiological diagnosis in patients after a standard right atriotomy.

Distinct functional properties of three human paired-box-protein, PAX8, isoforms generated by alternative splicing in thyroid, kidney and Wilms' tumors

The mammalian paired box (Pax) genes encode a family of transcription factors involved in embryogenesis. The murine and human Pax8 genes are expressed in developing and adult thyroid as well as in the developing secretory system and at the lower level in adult kidney. In the secretory system expression is localized to the induced, extensively differentiating parts that undergo a transition from mesenchyme to epithelium. The human PAX8 gene generates at least five different alternatively spliced transcripts encoding different PAX8 isoforms. These isoforms differ in their carboxy-terminal regions downstream of the paired domain that has been shown previously to be responsible for the DNA binding. The PAX8a isoform contains a 63 amino-acid serine-rich region that is absent in the isoform PAX8b whereas PAX8c reveals a novel 99-amino-acid proline-rich region. This proline-rich region arises due to an unusual reading-frame shift in the PAX8 transcript. RNAse protection and RT(reverse transcription)-PCR analysis show the expression of all three PAX8 transcripts in human thyroid, kidney and five Wilms' tumors. Band-shift assay indicates a greatly reduced binding affinity of the isoform PAX8c to a DNA sequence from the promoter of the thyroperoxidase gene compared to the binding of PAX8a and PAX8b to this sequence. Deletion analysis of murine PAX8a indicates that its activating domain residues at the carboxy terminus of the protein which is shared by isoforms PAX8a and PAX8b. In accordance with these data PAX8a and PAX8b activate transcription from a thyroglobulin promoter as well as from a cotransfected synthetic PAX8-specific promoter/chlorampericol acetyltransferase (CAT) reporter containing a Pax8-binding oligonucleotide in front of the basal herpes simplex virus thymidine kinase (HSV-TK) promoter (P11/12-TK-CAT). However if the basal HSV-TK promoter of this reporter is substituted by a minimal adenovirus E1b TATA element, PAX8a and PAX8b fail to activate transcription. Of the three chimaeric forms containing the GAL4 DNA-binding domain at the amino-terminal end fused to the corresponding carboxy-terminal regions of the PAX8 isoforms beginning immediately downstream of the paired domain only a GAL4-PAX8b fusion significantly activates transcription from a cotransfected GAL4-specific upstream-activating-sequence (UAS)-TK-CAT reporter. Substitution of the basal HSV-TK promoter in this reporter by the minimal E1b TATA element does not affect this activation. These results indicate that the PAX8 isoforms display different functional properties and may also function differently in vivo.(ABSTRACT TRUNCATED AT 400 WORDS)

A transcription initiation site for the hepatitis B virus X gene is directed by the promoter-binding protein

Recent studies have demonstrated the transacting function of the X gene product of hepatitis B virus. However, little information is available on the regulation of X gene expression. In this report, we first investigate a cellular factor regulating X gene transcription by DNA transfection, using the human hepatoma cell line HuH-7, which is permissive for HBV replication as well as X mRNA transcription. A sequence-specific cellular factor was found to bind to the promoter region upstream of the first ATG (nucleotide [nt] 1248) of the X open reading frame. DNase I footprinting analysis showed the binding sequence of this factor to be situated between nt 1097 and 1119, where an 8-bp palindrome structure resides. S1 nuclease analysis of X gene transcripts demonstrated the binding site to be adjacent to two major start sites (nt 1117 and 1125) of X mRNA. Second, we demonstrate that introduction of a mutation into the binding site gives rise to a loss of the binding with a concomitant shift of the transcription start site of X mRNA beyond the 8-bp palindrome structure, causing it to become more heterogeneous. Thus, the promoter-binding protein appears to be involved in directing the transcription initiation site of the X gene toward the downstream region of the X promoter when X protein is produced from X mRNA.

GHF-1-promoter-targeted immortalization of a somatotropic progenitor cell results in dwarfism in transgenic mice

During pituitary development, the homeo domain protein GHF-1 is required for generation of somatotropes and lactotropes and for growth hormone (GH) and prolactin (PRL) gene expression. GHF-1 mRNA is detectable several days before the emergence of GH- or PRL-expressing cells, suggesting the existence of a somatotropic progenitor cell in which GHF-1 transcription is first activated. We have immortalized this cell type by using the GHF-1 regulatory region to target SV40 T-antigen (Tag) tumorigenesis in transgenic mice. The GHF-Tag transgene caused developmental entrapment of somatotropic progenitor cells that express GHF-1 but not GH or PRL, resulting in dwarfism. Immortalized cell lines derived from a transgenic pituitary tumor maintain the characteristics of the somato/lactotropic progenitor in that they express GHF-1 mRNA and protein yet fail to activate GH or PRL transcription. Using these cells, we identified an enhancer that activates GHF-1 transcription at this early stage of development yet is inactive in cells representing later developmental stages of the somatotropic lineage or in other cell types. These experiments not only demonstrate the potential for immortalization of developmental progenitor cells using the regulatory regions from cell type-specific transcription factor genes but illustrate the power of such model systems in the study of developmental control.

The X gene of hepatitis B virus induced growth stimulation and tumorigenic transformation of mouse NIH3T3 cells

To examine the transforming potential of the X gene product of hepatitis B virus (HBV), the X-gene-containing region (referred to as the HBx region) was introduced into mouse NIH3T3 cells. Each transformed cell line expressed X-coding mRNA at a different level. A positive correlation was found between the level of X-coding mRNA and the saturation density of the cells. The HBx-transformed cell lines exhibited X protein production and tumor formation in nude mice. The function of HBV in oncogenesis may involve the continuous expression of the X-gene-coded product in the HBV DNA-integrated cells.

Identification of a promoter region for 3.6-kilobase mRNA of hepatitis B virus and specific cellular binding protein

The promoter region for transcription of the 3.6-kilobase mRNA of hepatitis B virus was identified by the chloramphenicol acetyltransferase assay by using HuH-7 hepatoma cells and was found to function directly in virus production by way of the transient expression system of HBV. The 5'-upstream sequence from nucleotides 1573 to 1657 (the transcription start site) was indispensable for promoter function, while the AT-rich sequence (from nucleotides 1581 to 1604) containing a directly repeated sequence TGTT connecting the same flanking sequence PyAAAGAC (where Py is a pyrimidine) at both sides was an essential element within this promoter region. A specific cellular factor which interacted with the essential element was detected in the HuH-7 cell extract. A similar binding factor was also observed in HepG2 and huH2-2 hepatoma cells. This factor may thus be responsible for regulating 3.6-kilobase mRNA, pregenome RNA transcription, or both.

Oncogenic potential of hepatitis B virus

The function of the X gene was clarified by examination of the transient production of hepatitis B virus (HBV) particles by transfected recombinant HBV DNA (pHBV-3 DNA) and its frameshift mutant (delta X) of the X open reading frame into hepatocellular carcinoma HuH-7 and HepG2 cells. No reduction of viral mRNAs was observed in the HuH-7 cells by the delta X mutant, whereas mRNAs underwent marked reduction in HepG2 cells. No reduction in core particle production was observed in HuH-7 cells, but in HepG2 cells reduction was considerable. To clarify the significance of the delta X mutation in the trans-acting function of the X gene in hepatoma cells, the chloramphenicol acetyl/transferase (CAT) assay was conducted. Transfection of plasmid pHBV-3 into HepG2 cells increased CAT activity of pSV2-CAT, while the delta X mutation clearly showed no stimulation of activity. On the other hand, in the HuH-7 cells, pHBV-3 exhibited no such stimulation. The trans-acting function of the X gene product in two different hepatoma cells was clearly shown to differ. Furthermore, transfection of X gene expression plasmid pKSV-HBx into mouse NIH3T3 cells increased the CAT activity of pSV2-CAT. Trans-activation was still detectable even following deletion of enhancer sequences in the pSV2CAT. The oncogenic potential of HBV is discussed with special attention to the X gene product, which may be able to activate a cellular transcription factor at the viral and cellular promotor sequences in the cells.

[Local hyperthermia using a device made of temperature-sensitive ferrite. The first report: temperature, output characteristics]

The basic study of intracavitary and interstitial hyperthermia was made with the Soft-Heating Method. In this method, a hybrid device composed of non-magnetic metal ring and ferrite rod is used as a heater. Being exposed to external magnetic field, the device produces heat, and its temperature rises to the Curie Temperature of the ferrite rod with self-regulation. The accuracy of the regulation is +/- 0.2 degrees C near the Curie Temperature which can be set up almost freely. In addition to that, the frequency of magnetic field is not so high (20-50 KHz) that there is no damping nor reflection of the field in a human body. Therefore the system seems to be very useful for hyperthermia of deep seated tumor. In this paper, experimental discussion of the possibility of local hyperthermia by the system is made. From the results, it is concluded that the system will be applied to clinical uses.

Glidobactins A, B and C, new antitumor antibiotics. II. Structure elucidation

The structures of new antitumor antibiotics, glidobactins A (Ia), B (Ib) and C (Ic) were elucidated by a combination of chemical and enzymatic degradations and spectral analyses. They have in common a cyclized tripeptide nucleus composed of L-threonine, 4(S)-amino-2(E)-pentenoic acid and erythro-4-hydroxy-L-lysine, and differ from each other in the unsaturated fatty acid moiety attached to the peptide.

Duck hepatitis B virus (DHBV) particles produced by transient expression of DHBV DNA in a human hepatoma cell line are infectious in vitro

Transfection of the human hepatocellular carcinoma cell line HuH7 with a plasmid containing a tandem copy of the duck hepatitis B virus DNA sequence resulted in transient replication of the virus. Viral particles secreted by transfected HuH7 cells exhibited physical properties similar to those of serum-derived duck hepatitis B virus and were infectious in primary duck hepatocyte cultures.

Integrated structures of duck hepatitis B virus DNA in hepatocellular carcinoma

The structure of integrated viral DNA in a hepatocellular carcinoma of a duck from Chi-tung county in China was analyzed. Three different clones of integrated viral DNA, lambda DHS 6-1, lambda DHS 6-2, and lambda DHE 6-2, were obtained from the neoplastic portion of the liver by molecular cloning. One of the three clones, lambda DHS 6-1, showed inverted repetition of integrated viral DNA with chromosomal flanking sequences. Another clone, lambda DHS 6-2, showed a head-to-head configuration of the core and surface gene regions of duck hepatitis B virus (DHBV) DNA. The virus-chromosome junctions were often located near direct repeat 1 or 2 of DHBV DNA in three independent clones. Nucleotide sequences at the virus-virus junctions in two clones, lambda DHS 6-1 and 6-2, indicated the possible rearrangement of chromosomal DNA and recombination of viral DNA. DHBV DNA appears to be integrated into the genome of hepatocytes in a manner similar to that of human and woodchuck hepatitis viruses. Thus, the duck system may serve as a useful animal model for the study of human hepatocarcinogenesis.

Production of hepatitis B virus surface antigen particles by the human hepatoma cell line huGK-14 in a serum-free medium

The human hepatoma cell line, huGK-14, containing integrated hepatitis B virus (HBV) DNAs, produced a large number of 23 nm spherical particles of HBV surface antigen (HBsAg) in a serum-free medium. These particles closely resembled the HBsAg particles found in the sera of HBV carriers and elicited a high antibody response in guinea pigs. The huGK-14 cells in a serum-free medium would provide a new, economic source of HBV vaccine.

RNA transcripts of hepatitis B virus in hepatocellular carcinoma

The states of hepatitis B virus DNA, RNA transcripts and antigens (HBsAg and HBcAg) were studied in the liver with hepatocellular carcinoma by blot hybridization and immunohistological methods. We used whole hepatitis B virus DNA and gene specific probes (S, C and X genes) for hybridization. Integrated viral DNA was found in all five tumors, but episomal DNA was not detected in the neoplastic tissue. In the nonneoplastic cirrhotic liver, episomal DNA was found in four cases and integrated viral DNA in four cases. A large amount of hepatitis B virus-specific RNA transcripts was demonstrated in nonneoplastic liver of all five cases. Two major transcripts, 2.4 and 3.4 kb in length, were identified. The former hybridized with the S gene probe and the latter with the C gene probe, suggesting that they were messenger RNAs for HBsAg and HBcAg, respectively. In contrast to nonneoplastic liver, RNA transcripts were found in the neoplastic portion in only two cases, small in quantity; they primarily hybridized with S and X, but not with C genes. Novel species of 4.0 and 3.9 kb transcripts were found in the neoplastic and the nonneoplastic portions, respectively, in one case. They may represent fusion transcripts of integrated viral DNA and cellular flanking sequences.

Multiple integration site of hepatitis B virus DNA in hepatocellular carcinoma and chronic active hepatitis tissues from children

Attention was directed to hepatitis B virus (HBV) integration in tissues obtained from an hepatocellular carcinoma (HCC) of an 11-year-old boy and from the liver of his 6-year-old brother, who had chronic active hepatitis. Multiple HBV DNA integration sites were demonstrated in both tissues. Cell population(s) in the HCC and liver from the patient with chronic active hepatitis were assumed to be heterogeneous with regard to HBV integration. The integrated forms in the two tissues showed similar genetic organization without gross rearrangement. The location of one of the virus-chromosomal junctions was restricted to the 5'-end region of the minus-strand DNA of HBV. The experimental results support our previous model for the mechanism of HBV integration, in which minus-strand replicative intermediates integrate into chromosomal DNA. The integrated HBV DNAs were conserved in the same region of the viral genome, spanning from the C gene through the S gene to the X gene, which contains intrinsic promoter-enhancer sequences.

Hepatitis B virus (HBV) particles are produced in a cell culture system by transient expression of transfected HBV DNA

An in vitro system for the production of hepatitis B virus (HBV) particles was established by the transient expression of transfected HBV DNA using a human hepatocellular carcinoma cell, HuH-7, as a recipient. The 3.6- and 2.2-kilobase transcripts observed were similar to those in virus-infected liver cells. Both transcripts revealed the microheterogeneity of their 5' ends. The formation of virus-related particles subsequent to the RNA transcription was demonstrated. The core particles observed in the cytoplasm and the virus particles secreted in the culture medium contained the replicative intermediates of HBV DNA and banded at densities of 1.35-1.36 g/cm3 and 1.22-1.24 g/cm3, respectively. Furthermore, the in vitro mutagenesis of the template HBV DNA demonstrated that the P gene as well as the C gene products were essential for the production of HBV particles.

[Studies on hypoaldosteronism associated with diabetes mellitus: response of plasma steroids to angiotensin II or ACTH administration]

This study was designed to clarify the cause of hyporeninemic hypoaldosteronism (HH) associated with diabetes mellitus. Fourty diabetic patients (DP) were divided into 3 groups; 12 patients without neuropathy or nephropathy, 13 with neuropathy and without nephropathy, and 15 with neuropathy and nephropathy; in the third group 3 HH patients were included. Fourteen normal subjects served as controls. In all DP and the normal subjects, plasma concentration of aldosterone (PAld), 18-hydroxycorticosterone (P18-OH-B), corticosterone (PB), 11-deoxycorticosterone (PDOC) and cortisol (PF) were measured before and after intravenous administration of angiotensin II (AII, 10 ng/kg/min, for 30 min) or ACTH (1-24 ACTH, 0.25 mg). In 27 DP, plasma renin activity (PRA) increased from 0.8 +/- 0.6 SD to 2.4 +/- 2.2 ng/ml/h (normal: 1.2 +/- 0.7 to 3.2 +/- 1.7 ng/ml/h) 2 hours after intravenous administration of furosemide (1 mg/kg) and assumption of the upright posture. No significant difference in PRA was found between DP and controls, whereas the response to these stimuli decreased significantly in 9 DP with neuropathy and nephropathy (from 0.4 +/- 0.2 to 0.7 +/- 0.4 ng/ml/h). The major results were as follows: 1) The mean of PAld (5.9 +/- 2.4 ng/100 ml) in DP was significantly lower than that in controls (7.7 +/- 2.2 ng/100 ml). There was no significant difference of PAld between DP without complications and controls. PAld in DP with neuropathy alone (5.0 +/- 1.5 ng/100 ml, p less than 0.05) and that in DP with neuropathy and nephropathy (4.7 +/- 2.4 ng/100 ml, p less than 0.05) were lower than that in controls. The mean of P18-OH-B (12.3 +/- 4.3 ng/100 ml) in DP was similar to that (14.2 +/- 3.2 ng/100 ml) in controls. P18-OH-B in DP without complications and that in DP with neuropathy alone were similar to that in controls. However, P18-OH-B (8.8 +/- 3.2 ng/100 ml) in DP with neuropathy and nephropathy was significantly lower than that in controls (p less than 0.001). No difference in PB, PDOC or PF was observed between DP and controls. 2) PAld increased from 6.0 +/- 2.5 ng/100 ml in DP (p less than 0.001) and from 7.6 +/- 2.2 to 15.7 +/- 5.3 ng/100 ml in controls (p less than 0.001) 30 min after A II infusion.(ABSTRACT TRUNCATED AT 400 WORDS)

[The effect of metoclopramide and dopamine on mineralocorticoid secretion--in vivo and in vitro studies]

There is considerable information suggesting that dopamine is a physiological regulator of aldosterone secretion. Metoclopramide, a specific dopamine antagonist, elicits a rapid rise in plasma aldosterone independent of the known aldosterone-regulating factors. However, the mechanism and the site of action of metoclopramide, whether adrenal or extra-adrenal, in stimulation of aldosterone production remain to be defined. The present studies were designed to investigate the mechanism of dopaminergic control of corticosteroid secretion and to determine at which step in the aldosterone biosynthetic pathway metoclopramide and dopamine exert their effect. Plasma concentrations of progesterone, 11-deoxycorticosterone (DOC), and cortisol were not altered by a bolus intravenous administration of 10 mg metoclopramide in 8 healthy male volunteers. Metoclopramide increased plasma aldosterone from 6.9 +/- 2.8 (Mean +/- 2SD) ng/100 ml to a maximum level of 18.2 +/- 4.7 ng/100 ml, 18-hydroxycorticosterone (18-OHB) from 12.6 +/- 6.5 ng/100 ml to a maximum of 41.3 +/- 7.3 ng/100 ml and corticosterone from 0.36 +/- 0.09 microgram/100 ml to a maximum of 0.85 +/- 0.22 microgram/100 ml. The aldosterone, 18-OHB and corticosterone responses displayed a parallel time course, with a significant response of each occurring within 5 minutes after metoclopramide administration. These data suggest that metoclopramide may modulate the activities of 18-hydroxylase and 11 beta-hydroxylase. Studies in vitro revealed that metoclopramide (10(-8)-10(-4) M had little effect on basal production of aldosterone, 18-OHB and corticosterone from human adrenal slices. Dopamine (10(-4) M) did not alter the basal secretion of aldosterone, 18-OHB and corticosterone, but suppressed the secretion of these 3 mineralocorticoids by ACTH, which were diminished by addition of 10(-4) M metoclopramide. There was a concentration-dependent inhibitory effect of dopamine on conversion of corticosterone to 18-OHB and DOC to corticosterone in vitro using bovine adrenal mitochondrial fractions. IC50 of dopamine inhibiting 18-hydroxylation and 11 beta-hydroxylation were 7.5 X 10(-7) M and 9.5 X 10(-4) M, respectively. It appears that physiological concentration of dopamine can modulate the activity of 18-hydroxylase enzyme. In summary, it can be concluded that the in vivo and in vitro studies are compatible with a view that dopamine has a physiological role in the regulation of aldosterone by modulating the activity of 18-hydroxylase enzyme.

Direct evidence for the expression of integrated hepatitis B virus DNA in human hepatoma tissue

The intracellular structure and expression of integrated hepatitis B virus (HBV) DNA in the hepatoma tissue #1707 obtained from an 11-year-old boy were studied. It was found that most of the HBV genome was present in the #1707 DNA. Virus-specific 21S mRNA was also demonstrated by blot hybridization. This is the first direct evidence for the expression of the integrated viral genome in human hepatoma tissue.

Effects of metoclopramide, a dopamine antagonist, on secretion of aldosterone and renin release in patients with primary aldosteronism

To assess the interaction between dopamine and aldosterone secretion in primary aldosteronism, the dopamine antagonist, metoclopramide (methoxy-2-chloro-5-procainamide), was given as an i.v. bolus (10 mg) to 5 patients with primary aldosteronism and 5 normal subjects treated with dexamethasone (2 mg/day) to eliminate an influence of ACTH. Metoclopramide increased plasma aldosterone concentration (PAC) in primary aldosteronism from 39.1 +/- 15.5 to 42.5 +/- 15.9 ng/100 ml (p less than 0.05) and also from 12.9 +/- 2.3 to 23.6 +/- 3.4 ng/100 ml (p less than 0.01) in normal subjects at 15 min. Plasma renin activity (PRA), and plasma concentrations of cortisol, potassium, and sodium did not significantly change with metoclopramide in either primary aldosteronism or normal subjects. Plasma prolactin increased by 12- and 20-fold in primary aldosteronism and in normal subjects, respectively, but there was no significant positive correlation between changes in PAC and in plasma prolactin in either primary aldosteronism or normal subjects. It is suggested that dopamine inhibits the secretion of aldosterone in primary aldosteronism as well as in normal subjects. It seems unlikely that dopamine affects the release of renin in primary aldosteronism.

[Relation between dopamine secretion and saltsensitivity in essential hypertension]

The study was designed to explore the mechanism of dopamine secretion related to blood pressure in patients with essential hypertension. The 19 patients with essential hypertension were administered to first 153 mEq of sodium and 70 mEq of potassium diet, next 51 mEq of sodium and finally 340 mEq of sodium for every one week. The patients whose mean blood pressure elevated 10 mmHg or more on the high-sodium loading and depleted 10 mmHg or more on the low-sodium loading were classified as A-, and depleted 10 mmHg or more on the high-sodium loading and elevated 10 mmHg or more on the low-sodium loading as B- and the other patients as C-group. The hypertensive patients were also classified to low- (below 1.0 ng/ml/h), normal- (from 1.0 to 6.0 ng/ml/h) and high- (above 6.0 ng/ml/h) renin groups from the results of plasma renin activity (PRA) obtained after an intravenous injection of furosemide (1 mg/kg) followed by 2-hour ambulation. PRA, plasma aldosterone concentration (PAC), plasma epinephrine concentration (PE), plasma norepinephrine concentration (PNE), plasma dopamine concentration (PDC), circulating plasma volume, body weight, hematocrit and pulse rate were measured at 8 a.m. after sodium loading for 8-days. The patients with essential hypertension were classified into 6 of A- and 2 of B- and 11 of C-groups with the maneuver of sodium loading. The A-group contained 5 patients with low-renin. The circulating plasma volume was relatively large (44.7 +/- 4.8 ml/kg) and markedly increased on the high-sodium loading in 6 patients of A-group. The increment of body weight was higher in A-group than the other groups on the high-sodium loading. In the 2 patients of B-group, hematocrit and pulse rate increased on the low-sodium and decreased on the high-sodium loading, and the variability were larger than the other groups. In the A-group, PRA was significantly low (0.5 +/- 0.4 ng/ml/h) and increased on the low-sodium loading and decreased on the high-sodium loading, and the variability of PRA was lesser than the other groups. In the A-group, PAC was within normal range (5.4 +/- 2.8 ng/dl) and the variation of PAC paralleled with the change of PRA, but the variability of PAC was remarkably low. PE and PNE were unchanged in the A- and the C-groups, but the significant high values were observed in the B-group on the high-sodium loading.