Search

Background: Few studies have investigated the importance of glycemic control in patients with diabetes mellitus (DM) for reducing the incidence of late target lesion revascularization (TLR) after implantation of new-generation drug-eluting stents (DES). Methods and Results: We retrospectively identified 1,568 patients who underwent new-generation DES implantation. Patients were divided into 3 groups based on diabetic status and glycemic control 1 year after the procedure: those without DM (non-DM group; n=1,058) and those with DM at follow-up with either good (HbA1c

Background: Pteridines are metabolites of tetrahydrobiopterin, which serves as co-enzyme of nitric oxide synthase. We sought to investigate the usefulness of pteridines as biomarkers for childhood asthma control. Methods: We conducted a single-center prospective cohort study involving 168 asthmatic children aged 4–17 years who visited the periodical asthma checkup program. Serum neopterin and biopterin levels were measured as pteridines at each visit along with measurement of FeNO, respiratory function tests, nasal eosinophil test, blood eosinophil count, and IgE level. We calculated coefficients for relation between pteridines and asthma control, which was assessed by questionnaires (JPAC: Japanese Pediatric Asthma Control Program). Results: A total of 168 participants aged 10.3 ± 3.39 years (mean ± SD) with asthma were recruited. The participants in this study contained 58 patients (34.5%) of complete-controlled based on JPAC, 132 patients (76.0%) of well-controlled group based on GINA. FeNO and serum neopterin level did not correlate with following period's JPAC scores. In contrast, serum biopterin level significantly correlated with following period's JPAC total score (Coefficients 0.398; 95% CI 0.164 to 0.632; p value 0.001) and frequency of wheezing during exercise (Coefficients 0.272; 95% CI 0.217 to 0.328; p value

A 19-year-old woman developed hypotension and abdominal distension during lumbar discectomy. Computed tomography revealed a right common artery injury and a large retroperitoneal hematoma. She was transferred to our hospital and brought to an angiography room directly. Endovascular balloon occlusion of the aorta was performed by cardiologists while surgeons were preparing for surgery. With the hemodynamics stabilized, the injured artery was repaired. In such a case, closing the artery as soon as possible, whether by clamping or by balloon occlusion, is vital. The ability to respond with a "Heart Team" is essential for a small-manpower hospital to rescue a patient with a serious condition.

Everolimus-eluting stent (EES) is effective for treating in-stent restenosis (ISR). However, the long-term incidence of target lesion revascularization (TLR) is unknown. Further, the role of post-intervention minimal stent area (MSA) measured by intravascular ultrasound (IVUS) in TLR is unknown in this setting.Overall, 223 ISR lesions (192 patients) that were treated with EES between 2010 and 2016 were analyzed retrospectively. Lesions were divided into two groups according to the post-intervention MSA [ ≤ 5.3 mm: 72 lesions (67 patients), and5.3 mm: 151 lesions (138 patients)]. The cut-off point was determined on the basis of receiver operating characteristic curve analysis.The cumulative 5-year incidence of TLR was significantly higher in the group with MSA of 5.3 mm or less than in the group with MSA more than 5.3 mm (15.8 and 7.2%, P = 0.01). After adjusting for confounders, the excess risk of the group with MSA of 5.3 mm or less relative to the group with MSA more than 5.3 mm for TLR remained significant [hazard ratio: 3.07, 95% confidence interval (CI): 1.17-8.51, P = 0.02]. Using multivariate logistic regression analysis, we identified female sex (odds ratio: 2.39, 95% CI: 1.06-5.49, P = 0.04) and stent size of 3.0 mm or less (odds ratio: 13.43, 95% CI: 6.23-32.38, P0.0001) as independent predictors of MSA of 5.3 mm or less.EES implantation for ISR was associated with an acceptable rate of TLR through long-term follow-up. Postintervention MSA of 5.3 mm or less was associated independently with a higher risk for TLR.

Background Data are scarce on the role of aortic valve area (AVA) to identify those patients with asymptomatic severe aortic stenosis (AS) who are at high risk of adverse events. We sought to explore the prognostic impact of AVA in asymptomatic patients with severe AS in a large observational database. Methods and Results Among 3815 consecutive patients with severe AS enrolled in the CURRENT AS (Contemporary Outcomes After Surgery and Medical Treatment in Patients With Severe Aortic Stenosis) registry, the present study included 1309 conservatively managed asymptomatic patients with left ventricular ejection fraction ≥50%. The study patients were subdivided into 3 groups based on AVA (group 1: AVA >0.80 cm2, N=645; group 2: 0.8 cm2 ≥AVA >0.6 cm2, N=465; and group 3: AVA ≤0.6 cm2, N=199). The prevalence of very severe AS patients (peak aortic jet velocity ≥5 m/s or mean aortic pressure gradient ≥60 mm Hg) was 2.0%, 5.8%, and 26.1% in groups 1, 2, and 3, respectively. The cumulative 5‐year incidence of AVR was not different across the 3 groups (39.7%, 43.7%, and 39.9%; P=0.43). The cumulative 5‐year incidence of the primary outcome measure (a composite of aortic valve–related death or heart failure hospitalization) was incrementally higher with decreasing AVA (24.1%, 29.1%, and 48.1%; P, See Editorial by Tribouilloy et al

Background KCNQ1-T587M is a C-terminal mutation correlated with severe phenotypes of long QT syndrome (LQTS). However, functional analysis of KCNQ1 channels with the T587M mutation showed a mild genotype in the form of haploinsufficiency in a heterologous expression system. This study sought to explore the molecular mechanism underlying the phenotype–genotype dissociation of LQTS patients carrying the KCNQ1-T587M mutation. Methods cDNAs for wild-type (WT) and KCNQ1 mutations (R259C and T587M) were transiently transfected into HEK293 cells stably expressing hERG (hERG-HEK), and whole-cell patch-clamp technique was performed to examine the effect of KCNQ1 mutations on IKr-like currents. In addition, fluorescence resonance energy transfer (FRET) was conducted to demonstrate the molecular interaction between KCNQ1 and hERG when co-expressed in HEK293 cells. Results KCNQ1-T587M mutation produced a significant (p Conclusions The disruption of hERG trafficking caused by the KCNQ1-T587M mutation is likely the reason why some patients exhibit severe LQTS phenotypes.

The aim of this study was to evaluate the prognostic impact of left ventricular ejection fraction (LVEF) in patients with severe aortic stenosis (AS).The prognostic impact of LVEF in severe AS remains controversial.Among 3,815 consecutive patients with severe AS enrolled in the CURRENT AS (Contemporary Outcomes After Surgery and Medical Treatment in Patients With Severe Aortic Stenosis) registry, the present study population consisted of 3,794 patients after excluding 21 patients without LVEF data. Patients were divided into 4 groups according to LVEF at index echocardiography (50%, 50% to 59%, 60% to 69%, and ≥70%; conservative strategy: n = 388, n = 390, n = 1,025, and n = 800; initial aortic valve replacement strategy: n = 206, n = 170, n = 375, and n = 440). Echocardiographic data were site reported, and there was no echocardiography core laboratory.In the conservative group, the cumulative 5-year incidence of the primary outcome measure (a composite of aortic valve-related death or heart failure hospitalization) was significantly higher in patients with LVEFs 50% and 50% to 59% than in those with LVEFs 60% to 69% and ≥70% (72.3%, 58.4%, 38.7%, and 35.0%, respectively, p 0.001), whereas in the initial aortic valve replacement group, the negative effect of low LVEF was markedly attenuated (20.2%, 20.3%, 17.7%, and 12.4%, respectively, p = 0.03). After adjusting for confounders, LVEF 50% (hazard ratio: 1.82; 95% confidence interval: 1.44 to 2.28; p 0.001) and 50% to 59% (hazard ratio: 1.77; 95% confidence interval: 1.42 to 2.20; p 0.001) but not 60% to 69% (hazard ratio: 1.14; 95% confidence interval: 0.94 to 1.39; p = 0.17) were independently associated with poorer outcomes compared with LVEF ≥70% (reference) in the conservative group. In the initial aortic valve replacement group, the adjusted risk for the primary outcome measure was not significantly different across the 4 LVEF groups.This study demonstrates that survival in patients with severe AS is impaired when LVEF is 60%, and these findings have implications for decision making with regard to the timing of surgical intervention.

Aims Andersen-Tawil Syndrome (ATS) and catecholaminergic polymorphic ventricular tachycardia (CPVT) are both inherited arrhythmic disorders characterized by bidirectional ventricular tachycardia (VT). The aim of this study was to evaluate the diagnostic value of exercise stress tests for differentiating between ATS and CPVT. Methods and results We included 26 ATS patients with KCNJ2 mutations from 22 families and 25 CPVT patients with RyR2 mutations from 22 families. We compared the clinical and electrocardiographic (ECG) characteristics, responses of ventricular arrhythmias (VAs) to exercise testing, and the morphology of VAs between ATS and CPVT patients. Ventricular arrhythmias were more frequently observed at baseline in ATS patients compared with CPVT patients [the ratio of ventricular premature beats (VPBs)/sinus: 0.83 ± 1.87 vs. 0.06 ± 0.30, P = 0.01]. At peak exercise, VAs were suppressed in ATS patients, whereas they were increased in CPVT patients (0.14 ± 0.40 vs. 1.94 ± 2.71, P

Background There are limited data regarding the risk stratification based on peak aortic jet velocity (Vmax) in patients with severe aortic stenosis ( AS ). Methods and Results Among 3815 consecutive patients with severe AS enrolled in the CURRENT AS (Contemporary Outcomes After Surgery and Medical Treatment in Patients With Severe Aortic Stenosis) registry, the study population consisted of 1075 conservatively managed patients with Vmax ≥4.0 m/s and left ventricular ejection fraction ≥50%. The study patients were subdivided into 3 groups based on Vmax (group 1, 4.0 ≤ Vmax AS ‐related events (aortic valve–related death or heart failure hospitalization) was incrementally higher with increasing Vmax (entire population; 38.0%, 49.4%, and 62.8%, P P =0.008; and asymptomatic patients; 29.4%, 38.9%, and 47.7%, P =0.005). After adjusting for confounders, the excess risk of group 2 and group 3 relative to group 1 for AS ‐related events remained significant (hazard ratio, 1.39; 95% CI , 1.07–1.81; P =0.02, and hazard ratio, 1.53; 95% CI , 1.17–2.00; P =0.002, respectively). The effect size of group 3 relative to group 1 for AS ‐related events in asymptomatic patients (N=479) was similar to that in symptomatic patients (N=596; hazard ratio, 1.59; 95% CI , 1.01–2.52; P =0.047, and hazard ratio, 1.67; 95% CI , 1.16–2.40, P =0.008, respectively), and there was no significant overall interaction between the symptomatic status and the effect of the Vmax categories on AS ‐related events (interaction, P =0.88). Conclusions In conservatively managed severe AS patients with preserved left ventricular ejection fraction, increasing Vmax was associated with incrementally higher risk for AS ‐related events. However, the cumulative 5‐year incidence of the AS ‐related events remained very high even in asymptomatic patients with less greater Vmax.

Background: Although the incidence of ventricular tachyarrhythmias associated with structural heart disease is highest in winter and during the daytime, seasonal and circadian variations among cardiac events in patients with congenital long QT syndrome (LQTS) remain unknown. The present study aims to determine seasonal and circadian cardiac events in patients with a congenital LQTS genotype. Methods and Results: The medical records of 196 consecutive patients with symptomatic LQTS (age, 32±19 years; female, n=133; LQT1, n=86; LQT2, n=95; LQT3, n=15) who were genotyped between 1979 and 2006 at 2 major Japanese institutions were retrospectively analyzed. The patients with LQT1, LQT2, and LQT3 developed 223,550 and 59 cardiac events during a mean follow-up of 26, 33, and 25 years, respectively. The numbers of cardiac events significantly peaked during the summer among those with LQT1 (P

Aims We aimed to examine the validity of heart rate (HR) at rest before β-blocker therapy as a risk factor influencing cardiac events (ventricular fibrillation, torsades de pointes, or syncope) in long QT type 2 (LQT2) patients. Methods and results In 110 genetically confirmed LQT2 patients (45 probands), we examined the significance of variables [HR at rest, corrected QT (QTc), female gender, age of the first cardiac event, mutation site] as a risk factor for cardiac events. We also evaluated frequency of cardiac events in four groups classified by the combination of basal HR and QTc with cutoff values of 60 b.p.m. and 500 ms to estimate if these two electrocardiographic parameters in combination could be a good predictor of outcome (mean follow-up period: 50 ± 39 months). Logistic regression analysis revealed three predictors: HR

Background: Atrioventricular block (AVB) sometimes complicates QT prolongation and torsades de pointes (TdP). Methods and Results: The clinical and genetic background of 14 AVB patients (57±21 years, 13 females) who developed QT prolongation and TdP was analyzed. Electrophysiological characteristics of mutations were analyzed using heterologous expression in Chinese hamster ovary cells, together with computer simulation models. Every patient received a pacemaker or implantable cardioverter defibrillator; 3 patients had recurrence of TdP during follow-up because of pacing failure. Among the ECG parameters, QTc interval was prolonged to 561±76ms in the presence of AVB, but shortened to 495±42ms in the absence of AVB. Genetic screening for KCNQ1, KCNH2, SCN5A, KCNE1, and KCNE2 revealed four heterozygous missense mutations of KCNQ1 or KCNH2 in 4 patients (28.6%). Functional analyses showed that all mutations had loss of functions and various gating dysfunctions of IKs or IKr. Finally, action potential simulation based on the Luo-Rudy model demonstrated that most mutant channels induced bradycardia-related early afterdepolarizations. Conclusions: Incidental AVB, as a trigger of TdP, can manifest as clinical phenotypes of long QT syndrome (LQTS), and that some patients with AVB-induced TdP share a genetic background with those with congenital LQTS. (Circ J 2010; 74: 2562-2571)

Introduction: Patients with long QT syndrome (LQTS) become symptomatic in adolescence, but some become at age of ≥20 years. Since it remains unknown whether clinical features of symptomatic LQTS patients differ depending on the age of onset, we aimed to examine whether triggers for cardiac events are different depending on the age in genotyped and symptomatic LQTS patients. Methods and Results: We identified 145 symptomatic LQTS patients, divided them into three groups according to the age of first onset of symptoms (young

Background Accelerated intermediate inactivation, which is caused by mutations in the cardiac voltage-gated sodium channel α-subunit gene ( SCN5A ), is one of the molecular mechanisms underlying Brugada syndrome. The N406S mutation associated with Brugada syndrome results in the accelerated intermediate inactivation, in addition to unique pharmacological characteristics. Methods Functional sodium channels were expressed transiently in HEK293 cells by transfecting equally the α- and β-subunit plasmids (1 μg/ml) and the sodium current were measured in whole-cell mode of patch-clamp recording. Results Since the N406S mutant channel has a greatly reduced use-dependent block of lidocaine, we took the advantage of the mutant channel to examine the effect of lidocaine on intermediate inactivation using wild-type (WT) and N406S mutant channels recombinantly expressed in HEK293 cells. Lidocaine (100 μM) slowed the recovery from the fast inactivation similarly for WT and N406S. On the other hand, whereas lidocaine slowed the recovery from the intermediate inactivation for WT, lidocaine accelerated the recovery for N406S. Activity-dependent loss of channel availability by repetitive 500-ms pulses was more strongly enhanced and accelerated by lidocaine for WT, but lidocaine exerted little effect on the N406S channel. Conclusion We demonstrate that lidocaine may suppress Brugada syndrome associated with the N406S mutation by preventing the sodium channel from accumulating in the intermediate inactivation state.

In a 34-year-old man showing short QT interval (QTc 329 ms), we identified a novel C-terminal KCNH2 mutation, R1135H. Using a heterologous expression system with CHO cells, the mutant channels were found to display a significantly slow deactivation, which resulted in a gain-of-function for reconstituted 'I(Kr)' channels. This mutation could modify clinical phenotypes for this patient.

Phenylketonuria (PKU) is a heterogeneous metabolic disorder caused by a deficiency in hepatic phenylalanine hydroxylase (PAH). On the basis of phenotype/genotype correlations, determination of phenylketonuric genotype is important for classification of the clinical phenotype and treatment of PKU, including tetrahydrobiopterin therapy. We characterized the genotypes of 203 Japanese patients with PKU and hyperphenylalaninemia using the following systems: (1) denaturing high-performance liquid chromatography with a GC-clamped primer; (2) direct sequencing; and, (3) multiplex ligation-dependent probe amplification. Of 406 mutant alleles, 390 (96%) were genotyped; 65 mutations were identified, including 22 new mutations. R413P, R241C, IVS4-1g>a, R111X and R243Q were prevalent mutations. Mutations prevalent in the Japanese cohort are also common in Korean and Northern Chinese populations, suggesting same origin. The spectrum of prevalent mutations was not significantly different among six Japanese districts, indicating that Japan comprises a relatively homogeneous ethnic group. We classified the mutations by clinical phenotypes and in vivo PAH activity and estimated the mutations with potential tetrahydrobiopterin (BH(4)) responsiveness. The frequency of BH(4) responsiveness based on the genotype was 29.1% in Japanese PKU patients. A catalog of PKU genotypes would be useful for predicting clinical phenotype, deciding on the subsequent treatment of PKU including BH(4) therapy, and genetic counseling in East Asia.

Background Long QT syndrome (LQTS) can be caused by mutations in the cardiac ion channels. Compound mutations occur at a frequency of 4% to 11% among genotyped LQTS cases. Objective The purpose of this study was to determine the clinical characteristics and manner of onset of cardiac events in Japanese patients with LQTS and compound mutations. Methods Six hundred three genotyped LQTS patients (310 probands and 293 family members) were divided into two groups: those with a single mutation (n = 568) and those with two mutations (n = 35). Clinical phenotypes were compared between the two groups. Results Of 310 genotyped probands, 26 (8.4%) had two mutations in the same or different LQTS-related genes (compound mutations). Among the 603 LQTS patients, compound mutation carriers had significantly longer QTc interval (510 ± 56 ms vs 478± 53 ms, P = .001) and younger age at onset of cardiac events (10 ± 8 years vs 18 ± 16 years, P = .043) than did single mutation carriers. The incidence rate of cardiac events before age 40 years and use of beta-blocker therapy among compound mutation carriers also were different than in single mutation carriers. Subgroup analysis showed more cardiac events in LQTS type 1 (LQT1) and type 2 (LQT2) compound mutations compared to single LQT1 and LQT2 mutations. Conclusion Compound mutation carriers are associated with a more severe phenotype than single mutation carriers.

Background— Drugs with I Kr -blocking action cause secondary long-QT syndrome. Several cases have been associated with mutations of genes coding cardiac ion channels, but their frequency among patients affected by drug-induced long-QT syndrome (dLQTS) and the resultant molecular effects remain unknown. Methods and Results— Genetic testing was carried out for long-QT syndrome–related genes in 20 subjects with dLQTS and 176 subjects with congenital long-QT syndrome (cLQTS); electrophysiological characteristics of dLQTS-associated mutations were analyzed using a heterologous expression system with Chinese hamster ovary cells together with a computer simulation model. The positive mutation rate in dLQTS was similar to cLQTS (dLQTS versus cLQTS, 8 of 20 [40%] versus 91 of 176 [52%] subjects, P =0.32). The incidence of mutations was higher in patients with torsades de pointes induced by nonantiarrhythmic drugs than by antiarrhythmic drugs (antiarrhythmic versus others, 3 of 14 [21%] versus 5 of 6 [83%] subjects, P KCNQ1 and KCNH2 mutant channels showed complex gating defects without dominant negative effects or a relatively mild decreased current density. Drug sensitivity for mutant channels was similar to that of the wild-type channel. With the Luo-Rudy simulation model of action potentials, action potential durations of most mutant channels were between those of wild-type and cLQTS. Conclusions— dLQTS had a similar positive mutation rate compared with cLQTS, whereas the functional changes of these mutations identified in dLQTS were mild. When I Kr -blocking agents produce excessive QT prolongation (dLQTS), the underlying genetic background of the dLQTS subject should also be taken into consideration, as would be the case with cLQTS; dLQTS can be regarded as a latent form of long-QT syndrome.

QT prolongation, a risk factor for arrhythmias, can result from genetic variants in one (or more) of the genes governing cardiac repolarization as well as intake of drugs known to affect a cardiac K+ channel encoded by human ether-a-go-go–related gene (HERG). In this paper, we will report a case of drug-induced long QT syndrome associated with an H1-receptor antagonist, hydroxyzine, in which a mutation was identified in the HERG gene. After taking 75 mg of hydroxyzine for several days, a 34-year-old female began to experience repetitive syncope. The deleterious effect of hydroxyzine was suspected because QTc interval shortened from 630 to 464 ms after cessation of the drug. Later on, the patient was found to harbor an A614V-HERG mutation. By using the patch-clamp technique in the heterologous expression system, we examined the functional outcome of the A614V mutation and confirmed a dominant-negative effect on HERG expression. Hydroxyzine concentration-dependently inhibited both wild-type (WT) and WT/A614V-HERG K+ currents. Half-maximum block concentrations of WT and WT/A614V-HERG K+ currents were 0.62 and 0.52 μM, respectively. Thus, accidental combination of genetic mutation and intake of hydroxyzine appeared to have led to a severe phenotype, probably, syncope due to torsade de pointes. Keywords:: hydroxyzine, QT prolongation, human ether-a-go-go–related gene (HERG), potassium channel, torsade de pointes

ObjectivesThis study aims to address whether D85N, a KCNE1 polymorphism, is a gene variant that causes long QT syndrome (LQTS) phenotype.BackgroundKCNE1 encodes the beta-subunit of cardiac voltage-gated K+channels and causes LQTS, which is characterized by the prolongation of the QT interval and torsades de pointes, a lethal arrhythmia. D85N, a KCNE1 polymorphism, is known to be a functional variant associated with drug-induced LQTS.MethodsIn order to elucidate the prevalence and clinical significance of this polymorphism, we performed genetic screening in 317 LQTS probands. For comparison, we examined its presence in 496 healthy control subjects. We also conducted biophysical assays for the D85N variant in mammalian cells.ResultsThe allele frequency for D85N carriers was 0.81% in healthy people. In contrast, among LQTS probands, there were 1 homozygous and 23 heterozygous carriers (allele frequency 3.9%). Seven of 23 heterozygous carriers had additional mutations in LQTS-related genes, and 3 female subjects had documented factors predisposing to the symptom. After excluding these probands, the D85N prevalence was significantly higher compared with control subjects (allele frequency 2.1%, p < 0.05). In a heterologous expression study with Chinese hamster ovarian cells, KCNE1-D85N was found to exert significant loss-of-function effects on both KCNQ1- and KCNH2-encoded channel currents.ConclusionsThe KCNE1-D85N polymorphism was significantly more frequent in our LQTS probands. The functional variant is a disease-causing gene variant of LQTS phenotype that functions by interacting with KCNH2 and KCNQ1. Since its allele frequency was ∼1% among control individuals, KCNE1-D85N may be a clinically important genetic variant.

Background In the LQT2 form of long QT syndrome (LQTS), mutation sites are reported to correlate with clinical phenotypes in Caucasians, but the relationship in Asian patients remains unknown. The present study was designed to determine whether the location of KCNH2 mutations would influence the arrhythmic risk in LQT2 patients. Methods and Results In 118 genetically-confirmed LQT2 patients (69 families, 62 KCNH2 mutations), the ECG parameters, Schwartz scores, and the incidence of cardiac events, defined as syncope, aborted cardiac arrest, and sudden cardiac death, were evaluated. To examine the effect of mutation sites, the participants were divided accordingly: pore (n=56) and non-pore (n=62) groups. The corrected QTend interval was significantly greater in the pore than in the non-pore group (QTc; 522±63 ms vs 490±49 ms, p=0.002). In this study, the clinical course of each of the probands did not differ according to the mutation sites, whereas non-probands carrying the pore site mutation experienced their first cardiac events at significantly younger age than those with the non-pore site mutation (log-rank, p=0.0005). Conclusions In a Japanese LQT2 cohort, family members with the pore site mutation were at higher arrhythmic risk than those with the non-pore site mutation. (Circ J 2008; 72: 694 - 699)

OBJECTIVES We aimed to examine whether triggers for cardiac events are different depending on the age in genotyped and symptomatic long QT syndrome (LQTS) patients. BACKGROUND Patients with LQTS become symptomatic in adolescence, but some at age ≥20 y/o. It remains unknown whether clinical features of these symptomatic LQTS patients differ depending on the onset of age. METHODS Study cohort consisted of consecutive 108 symptomatic LQTS patients (34 males and 74 females from 88 families) who were identified to carry the following genotypes; LQT1 (n = 48), LQT2 (n = 52), LQT3 (n = 8). They were divided into 2 groups according to the age of their first onset of symptoms (low age adrenergically-mediated factors; exercise, emotional stress, loud noise and arousal, vagally-mediated factors; rest/sleep, and secondary factors; drugs, hypokalemia, and bradycardia. RESULTS Percentage of patients with family history was significantly higher in the low age group (68% vs. 39%; p = 0.005), and prevalence of females and probands were significantly higher in the high age group (60% vs. 88%; p = 0.004, 75% vs. 97%; p = 0.006, respectively). There were no significant differences in both QTc intervals (523 ± 7 ms vs. 505 ± 10; p = 0.15) and Schwartz scores (6.3 ± 0.2 vs. 5.6 ± 0.3; p = 0.06) between the 2 groups. In the low age group, 76% of the cardiac events were initiated by adrenergically-mediated factors, and 20% were vagally mediated, but none was triggered by secondary factors. In contrast, in the high age group, 48% of the cardiac events were triggered by secondary factors, 12% adrenergically-mediated, and 18% vagally-mediated factors. The prevalence of secondary factors were as follows; 0/75 [0%] in low age vs. 16/33 [48%] in high age; p < 0.001. About the subdivision of secondary triggers on the genotype, hypokalemia was only observed in LQT1, drugs mainly in LQT2, and bradycardia only in LQT2. CONCLUSION Arrhythmic triggers in LQTS differ depending on the age of the patients, stressing the importance of age-related therapy for genotyped LQTS patients.

BH(4) administration results in the reduction of blood phenylalanine level in patients with tetrahydrobiopterin (BH(4))-responsive phenylalanine hydroxylase (PAH) deficiency. The mechanism underlying BH(4) response remains unknown. Here, we studied the effects of BH(4) and phenylalanine on in vivo PAH activity of normal controls using the phenylalanine breath test (PBT) by converting l-[1-(13)C] phenylalanine to (13)CO(2). Phenylalanine oxidation rates were expressed as Delta(13)C ((13)CO(2)/(12+13)CO(2), per thousand) and cumulative recovery rates over 120min (CRR(120), %; total amount of (13)CO(2)/the administered dose of (13)C-phenylalanine). Under physiological conditions of blood phenylalanine, BH(4) administration reduced the Delta(13)C peak from 40.8 per thousand to 21.6 per thousand and CRR(120) from 16.9% to 10.2%. Under high blood phenylalanine conditions, administration of BH(4) increased the Delta(13)C peak from 30.7 per thousand to 46.0 per thousand, while the CRR(120) was similar between phenylalanine (19.9%) and phenylalanine+BH(4) (21.1%) groups. Corrected Delta(13)C and CRR(120) were calculated against serum phenylalanine levels to remove the effects of phenylalanine loading. After BH(4) administration, the corrected Delta(13)C peak increased from 82.7 per thousand to 112.6 per thousand, while the corrected CRR(120) was similar (47.6% and 45.6%). These results indicate that phenylalanine worked as a regulator of in vivo PAH by serving as both a substrate and an activator for the enzyme. Excessive dosages of BH(4) inhibited PAH under normal phenylalanine conditions and activated PAH under conditions of high phenylalanine. The regulation system is therefore designed to maintain phenylalanine levels in the human body. Appropriate BH(4) supplementation must be reviewed in patients with BH(4)-responsive PAH deficiency.

This study compared the effects of amlodipine and valsartan on the sympathetic nervous system, the renin-angiotensin-aldosterone system, and brain natriuretic peptide, which are considered important parameters of the long-term prognosis. Seventy-three elderly patients, who had received antihypertensive treatment for more than 6 months with amlodipine, participated in this study. They were randomized to the V group (n = 36) and switched to valsartan from amlodipine, or to the A group (n = 37), which continued treatment with amlodipine. The dose of valsartan was set as that which controlled the blood pressure to the same extent as before switching. Blood samples were measured before and after 6 months of therapy. Data were analyzed by two-way analysis of variance with the Newman-Keuls test. In the V group, norepinephrine (from 597.0 +/- 52.9 to 475 +/- 43.8 pg/ml, p < 0.05) and aldosterone (from 74.5 +/- 7.0 to 53.9 +/- 5.3 pg/ml, p < 0.001) were decreased significantly after 6 months, although norepinephrine and aldosterone levels were unchanged in the A group. However, brain natriuretic peptide did not show a difference between the two groups. These findings suggested that valsartan is probably superior to amlodipine with respect to less activation of the sympathetic nervous system and preventing upregulation of the renin-angiotensin-aldosterone system.

The formation equilibria and thermodynamic properties of the alkaline-earth metal (M = Mg2+, Ca2+, Sr2+ or Ba2+) complexes of nitrilotris(methylenephosphonic acid)(H6ntmp) and ethylenediamine-tetrakis(methylenephosphonic acid)(H8edtmp) have been studied by means of potentiometry, NMR spectroscopy and calorimetry at 25.0 °C and at an ionic strength of 0.1 mol dm–3(KNO3). The complex formation constants and the protonation constants of the complexes were determined from the potentiometric titration data. Thermodynamic parameters of the protonation of the ligand, and the formation and protonation of the metal complexes of ntmp and edtmp were evaluated from the calorimetric titration data. The first protonation on the nitrogen atom of ntmp is significantly exothermic and it is followed by the endothermic protonation on the phosphonate O–. The protonations of edtmp are exothermic up to the third step. The formation of magnesium complexes of ntmp and edmp is endothermic and entropy driven, whereas that of the complexes of Ca2+, Sr2+ and Ba2+ is weakly exothermic. This behaviour is analogous to that of aminopolycarboxylate complexes. The results of calorimetric measurements of ntmp complexes support the structure of protonated alkaline-earth metal–ntmp complexes predicted from the stability and NMR data, i.e. the first protonation of the metal complexes occurs on the nitrogen atom of the ligand, rupturing the M–N bond. The thermodynamic behaviour of the edtmp complexes is considerably complicated. In the analysis of the pH dependence of the 31P NMR signals, the chemical shift of each species of ligand and its metal complexes was evaluated by using the formation constants obtained by potentiometry. The change in the chemical shift of the complexes upon protonation supports the structures of the alkaline-earth metal complexes predicted from the thermodynamic parameters.

Benzyl alcoholysis and hydrolysis of tetrakis-N-(benzyloxycarbonyl)fortimicin B and further transformation of the solvolysis products are described. Several derivatives of 6-epi-purpurosamine B and fortamine potentially useful for the synthesis of fortimicin analogs are presented.