P1357 Left atrial function decreases with age in patients with repaired tetralogy of Fallot decrease

BACKGROUND

Left ventricular function has been shown to be an important prognostic indicator in patients with repaired tetralogy of Fallot (rTOF) and tends to decrease with age. In recent years, left atrial (LA) function was reported to be a useful prognostic indicator more than or equal to left ventricular function in acquired heart diseases. However, atrial function in rTOF has not yet been sufficiently examined.

PURPOSE

The aim of this study was to investigate the relationship between LA dysfunction and age in rTOF using strain analysis.

METHODS

In order to assess the relationship between LA function and age, we recruited 59 patients with rTOF ranging in age from 5-40 years. We stratified the patients into 3 groups (T1: 5-10 years, T2: 11-20 years, T3: 21-40 years) and divided 54 controls of similar age into 3 corresponding groups (N1, N2, and N3). Two-dimensional speckle tracking images (2D-STI) obtained from four- and two-chamber views were used to assess LA functions by measuring reservoir, conduit, and pump strain. Additionally, we measured the strain rate (SR) in the systole, early diastole, and late diastole.

RESULTS

LA reservoir strain (37.4 ± 2.2% vs. 47.9 ± 1.7%, P= 0.004), LA pump strain (8.3 ± 1.4% vs. 14.1 ± 2.7%, p <.001), atrial systolic LA-SR (1.5 ± 0.4% vs. 2.4 ± 0.6%, p <.001), and systolic LA-SR (1.5 ± 0.3% vs. 2.1 ± 0.4%, p = 0.003) were significantly decreased in T3 compared with N3. Although only LA conduit strain decreased with aging (r = -0.3204, p = 0011) in controls, all of the LA reservoir (r = -0.325, p = 0.020), conduit (r = -0.314, p = 0.025), and pump strain (r = -0.481, p < 0.001) in rTOF decreased with aging.

Early diastole SR was significantly decreased in the T1 and T3 groups compared with the N1 and N3 groups (T1 vs N1, 3.00 ± 0.63% vs. 4.03 ± 0.0.80%, p <.0.001, T3 vs N3, 2.31 ± 0.57% vs.3.31 ± 0.47%, p < 0.001). Both systolic SR and late diastole SR decreased in T3 group compared with the N3 (1.54 ± 0.32% vs. 2.08 ± 0.42%, p = 0.003, 1.42 ± 0.32% vs.2.42 ± 0.61%, p < 0.001), respectively. Although only early diastole SR decreased with aging (r = -0.415, p < 0.001) in controls, all of the systole (r = -0.287, p = 0.041), early diastole (r = -0.337, p = 0.019), and late diastole SR (r = -0.407, p = 0.003) in rTOF decreased with aging.

CONCLUSIONS

In rTOF, most of the LA functions assessed by strain analysis decreased compared to normal controls in over 20 years old age. Furthermore, all measured functions decreased with age in rTOF while only two parameters decreased with age in normal controls. These results suggest that LA function may be an important indicator in long-term rTOF follow-up. These are new insights into LA function in patients with rTOF.

P1358 New insights into cardiac dysfunction assessed by left atrial function in patients with type 1 diabetes mellitus

BACKGROUND

There have been many reports of heart failure due to diabetic cardiomyopathy and decreased left ventricular (LV) function with increasing age in patients with type 1 diabetes mellitus (T1DM). Recently, although left atrial (LA) function has been occasionally reported to be a more useful prognostic indicator than LV function in acquired heart diseases, LA function in patients with T1DM has not yet been studied.

PURPOSE

To investigate LA dysfunction in patients with T1DM.

METHODS

Fifty patients with T1DM were recruited (age, 5–41 years). We excluded patients who had a history of heart disease, hypertension, and those taking cardioprotective agents. The patients and 50 age-matched controls were classified into 3 age groups (D1, C1, 5–14 years; D2, C2, 15–29 years; D3, C3, 30–41 years). The LA phasic function serving as the reservoir, conduit, and pump strains; the LA strain rate (SR) in the systole, early diastole, and late diastole; and the LV global longitudinal strain (LV-LS) as determined via 2-dimensional speckle tracking imaging were measured from the apical four- and two-chamber views. We also calculated the LA stiffness index as the ratio of E/e’ to the LA reservoir strain.

RESULTS

There was no significant difference in left ventricular ejection fraction in each age group. The LA reservoir strains in D2 and D3 were significantly lower than those in C2 (40.8 ± 5.7% vs. 47.2 ± 5.5%, p = 0.005) and C3 (39.2 ± 5.5% vs. 47.3 ± 5.7%, p = 0.004), respectively. The LA conduit strain in D2 was significantly lower than that in C2 (28.9 ± 5.8% vs. 35.0 ± 5.0%, p = 0.006). The LA pump strain and the three phases of LA SR were not significantly different among the age groups. The LA stiffness index in D3 increased significantly compared to that in N3 (0.18 ± 0.05 vs. 0.13 ± 0.01, p <0.001). The LV-LS in D2 and D3 was significantly lower than that in C2 (-15.7 ± 1.7% vs. -18.7 ± 2.1%, p <0.001) and C3 (-15.3 ± 1.8% vs. -19.3 ± 2.0%, p <0.001), respectively. The LA reservoir strain significantly correlated with LV-LS (r = -0.468, p < 0.001). Both the LA reservoir strain and LV-LS in patients with T1DM decreased significantly (p = 0.028, p < 0.042, respectively) and correlated with increasing age (r = -0.323, r = 0.286, respectively). The LV stiffness index did not correlate with age or LV-LS.

CONCLUSIONS

The LA reservoir strain might be as useful as LV-LS as an early marker of cardiac dysfunction in patients with T1DM. The correlation coefficient between the LA reservoir strain and LV-LS was not strong. Therefore, although LV-LS might affect the LA reservoir strain, it might represent other aspects of cardiac dysfunction. The increase of LA stiffness might represent the changes in LA wall properties and could be another useful indicator of cardiac dysfunction during long-term follow-ups, which is independent of LV-LS. Overall, these findings provide new insights into cardiac dysfunction in patients with T1DM.

P1745Clinical characteristics and long-term outcome in patients with helicopter-transported acute coronary syndrome after primary percutaneous coronary intervention

Background

Reducing delay to percutaneous coronary intervention improves functional outcome and reduces long-term mortality. Transportation by helicopter is often quicker than ground transport and thus may improve overall prognosis through reduced ischemic injury and infarction size. Our hospital is located on the medically-depopulated peninsula surrounded by mountain. The journey from the southern tip of the peninsula to the critical care medical center of our hospital take 1.5 hour by a ground ambulance but only 15 minutes by helicopter.

We compared the clinical characteristics and long-term mortality between air and ground transport of ACS patients for primary PCI.

Methods

We conducted an observational cohort study evaluating 2324 patients (mean age 68.5±12.0, male 75.2%) with ACS underwent primary PCI between April 2004 and December 2017 at our hospital.

We divided into three groups according to transportation system type (air, ground, walk-in).

The primary outcome was defined as all-cause death during the long-term follow-up.

Results

Among the entire cohort, 577 patients (24.8%) were transported by air. 1326 (57.1%) patients by ambulance, 421 (18.1%) patients by walk. Baseline characteristics were comparable, but patients by air had a higher prevalence of ST-elevation myocardial infarction.

The rate of long-term mortality was comparable during the median follow up of 6 years (air, 21.1% vs. ground, 21.4% vs. walk-in, 21.1%, respectively, log-rank p=0.72). Multivariate Cox regression analysis showed no significant association between air transportation and long-term mortality (Adjusted HR [vs ground] 1.05, 95% CI 0.60–1.78, p=0.85 and [vs walk-in] 0.94, 95% CI 0.62–1.43, respectively, p=0.77).

Kaplan-Meier curve

Conclusions

The rate of long-term mortality in patients with ACS transported by air was comparable with those transported by ground.

p62/Sqstm1 promotes malignancy of HCV-positive hepatocellular carcinoma through Nrf2-dependent metabolic reprogramming

p62/Sqstm1 is a multifunctional protein involved in cell survival, growth and death, that is degraded by autophagy. Amplification of the p62/Sqstm1 gene, and aberrant accumulation and phosphorylation of p62/Sqstm1, have been implicated in tumour development. Herein, we reveal the molecular mechanism of p62/Sqstm1-dependent malignant progression, and suggest that molecular targeting of p62/Sqstm1 represents a potential chemotherapeutic approach against hepatocellular carcinoma (HCC). Phosphorylation of p62/Sqstm1 at Ser349 directs glucose to the glucuronate pathway, and glutamine towards glutathione synthesis through activation of the transcription factor Nrf2. These changes provide HCC cells with tolerance to anti-cancer drugs and proliferation potency. Phosphorylated p62/Sqstm1 accumulates in tumour regions positive for hepatitis C virus (HCV). An inhibitor of phosphorylated p62-dependent Nrf2 activation suppresses the proliferation and anticancer agent tolerance of HCC. Our data indicate that this Nrf2 inhibitor could be used to make cancer cells less resistant to anticancer drugs, especially in HCV-positive HCC patients.

HERP, a new primary target of Notch regulated by ligand binding

Notch signaling dictates cell fate and critically influences cell proliferation, differentiation, and apoptosis in metazoans. Ligand binding initiates the signal through regulated intramembrane proteolysis of a transmembrane Notch receptor which releases the signal-transducing Notch intracellular domain (NICD). The HES/E(spl) gene family is a primary target of Notch and thus far the only known Notch effector. A newly isolated HERP family, a HES-related basic helix-loop-helix protein family, has been proposed as a potential target of Notch, based on its induction following NICD overexpression. However, NICD is physiologically maintained at an extremely low level that typically escapes detection, and therefore, nonregulated overexpression of NICD-as in transient transfection-has the potential of generating cellular responses of little physiological relevance. Indeed, a constitutively active NICD indiscriminately up-regulates expression of both HERP1 and HERP2 mRNAs. However, physiological Notch stimulation through ligand binding results in the selective induction of HERP2 but not HERP1 mRNA and causes only marginal up-regulation of HES1 mRNA. Importantly, HERP2 is an immediate target gene of Notch signaling since HERP2 mRNA expression is induced even in the absence of de novo protein synthesis. HERP2 mRNA induction is accompanied by specific expression of HERP2 protein in the nucleus. Furthermore, using RBP-Jk-deficient cells, we show that an RBP-Jk protein, a transcription factor that directly activates HES/E(spl) transcription, also is essential for HERP2 mRNA expression and that expression of exogenous RBP-Jk is sufficient to rescue HERP2 mRNA expression. These data establish that HERP2 is a novel primary target gene of Notch that, together with HES, may effect diverse biological activities of Notch.

HERP, a novel heterodimer partner of HES/E(spl) in Notch signaling

HERP1 and -2 are members of a new basic helix-loop-helix (bHLH) protein family closely related to HES/E(spl), the only previously known Notch effector. Like that of HES, HERP mRNA expression is directly up-regulated by Notch ligand binding without de novo protein synthesis. HES and HERP are individually expressed in certain cells, but they are also coexpressed within single cells after Notch stimulation. Here, we show that HERP has intrinsic transcriptional repression activity. Transcriptional repression by HES/E(spl) entails the recruitment of the corepressor TLE/Groucho via a conserved WRPW motif, whereas unexpectedly the corresponding-but modified-tetrapeptide motif in HERP confers marginal repression. Rather, HERP uses its bHLH domain to recruit the mSin3 complex containing histone deacetylase HDAC1 and an additional corepressor, N-CoR, to mediate repression. HES and HERP homodimers bind similar DNA sequences, but with distinct sequence preferences, and they repress transcription from specific DNA binding sites. Importantly, HES and HERP associate with each other in solution and form a stable HES-HERP heterodimer upon DNA binding. HES-HERP heterodimers have both a greater DNA binding activity and a stronger repression activity than do the respective homodimers. Thus, Notch signaling relies on cooperation between HES and HERP, two transcriptional repressors with distinctive repression mechanisms which, either as homo- or as heterodimers, regulate target gene expression.

[Effect of actarit combination therapy in patients with active rheumatoid arthritis resistant to gold agents]

We investigated the utility of combination therapy of actarit with gold agents in patients with active rheumatoid arthritis resistant to gold agents even after the administration of gold agents for longer than 24 weeks in principle. 1. In the final global improvement rate by the combination therapy of actarit with gold agents, the ratio of "improved" and/or better was 30.8% (12/39). 2. The clinical evaluation items which showed significant improvement were grip strength, ESR, number of painful joints, number of swollen joints, active joint count, duration of morning stiffness and Lansbury's activity index. 3. ADRs were observed in 6 patients per 75 patients (8.0%), but there was no serious ADR.

Humoral factor(s) produced by pressure overload enhance cardiac hypertrophy and natriuretic peptide expression

Chronic pressure overload is known to increase cardiac mass and expression levels of both atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) mRNAs. Although mechanical stretching of cardiac myocytes could cause these changes, humoral factor(s) secondary to pressure overload may also be involved. To dissociate humoral effects from the effects of mechanical loading on cardiac hypertrophic responses, we examined expression of ANP and BNP at both mRNA and protein levels and proportions of myosin isoforms in transplanted cervical hearts that were mechanically unloaded under conditions with or without hypertension by aortic coarctation. Seven days after transplantation, cardiac atrophy that usually occurs in transplanted hearts without hypertension by coarctation was prevented in the transplanted hearts with hypertension by coarctation. The levels of expression of ANP and BNP mRNAs were increased in the transplanted hearts with relative to those without hypertension by coarctation. The plasma level of angiotensin II was higher in rats with than without hypertension by coarctation. Plasma endothelin-1 levels were not significantly different between the two groups. In addition, levels of expression of ANP and BNP mRNAs were increased in the transplanted hearts without hypertension relative to those in the in situ hearts. The proportion of the V3 myosin isoform was also increased in the transplanted hearts without hypertension relative to the in situ hearts. These results indicate that humoral factor(s) secondary to the pressure overload produced by aortic coarctation enhanced the cardiac hypertrophic response and elevated the levels of mRNAs encoding these embryonic markers. Moreover, our findings regarding ANP and BNP expression in the transplanted hearts provide additional evidence that the fetal genes are reexpressed during the process of cardiac atrophy as well as in cardiac hypertrophy.

Increased friction of animal joints by experimental degeneration and recovery by addition of hyaluronic acid

OBJECTIVE: To investigate the lubricating ability in osteoarthritic (OA) stifle joints. DESIGN: An experimental study in rabbit stifles in vitro. BACKGROUND: The lubricating ability in OA joints, and the effects of the application of hyaluronic acid (HA), a drug for OA, to the osteoarthritic joints have not yet been reported. METHODS: The friction in OA stifles induced by two different methods, the intra-articular injection of papain, and transection of the anterior cruciate ligament (ACL) was measured using a robotic arm under force control. RESULTS: The frictional coefficient in the papain-injected model, that caused slight degeneration in the articular cartilage, was 1.3 to 1.8 times as large as that in the contralateral uninjected stifles. The elevated values decreased significantly by addition of HA to the articular surface (P < 0.05). In another group (n = 4), the frictional coefficient in the stifle at 9 months after ACL transection that caused severe degeneration in the articular cartilage was 1.6 to 7.8 times as large as that in the contralateral unoperated stifle. The addition of HA decreased the elevated values in three of the four ACL-transected joints. CONCLUSION: Friction was higher in the OA joints than in the healthy joints. The addition of HA was effective in the early stage of OA represented by papain injected case, while its effect seems not to be evident for advanced OA produced ACL transection which accompanies macroscopic shape changes. RELEVANCE: The present findings are relevant to the current research investigating the case of human osteoarthritis. We measured the frictional coefficients of experimentally degenerated rabbit stifles. The frictional coefficients can be used as an index of joint degeneration. We also assessed the recovery of the lubricating ability by addition of hyaluronic acid, a drug used for human osteoarthritis.

Endothelin-1 and its binding sites are upregulated in pressure overload cardiac hypertrophy

The purpose of this study was to determine whether endothelin and endothelin receptors play an important role in the development of cardiac hypertrophy due to pressure overload in vivo. Cardiac hypertrophy was produced by placing a constricting clip around the suprarenal abdominal aorta of rats. Hemodynamic parameters and plasma and ventricular concentrations of endothelin-1 (ET-1) were measured in control unoperated rats, and 30 min, 2 and 6 h, and 1 and 8 days after operation in pressure overload rats and sham-operated rats. The density and dissociation constant of ET-1 binding sites were also measured in control rats and 1 and 8 days after pressure overload and sham operation. Additionally, in situ mRNA hybridization for preproendothelin-1 (preproET-1) mRNA was performed to determine which cells were responsible for increased ET-1 levels. Ventricular ET-1 levels increased markedly on day 8 of pressure overload, whereas plasma ET-1 levels increased transiently only 30 min after operation, quickly returning to control level. In addition, ventricular ET-1 levels on day 8 showed a significant positive correlation with the degree of cardiac hypertrophy. In situ mRNA hybridization revealed that cardiac myocytes expressed preproET-1 mRNA in hypertrophied hearts in vivo. In accord with the elevation of ventricular ET-1 levels, the density of ET-1 binding sites was increased significantly, without affecting their binding affinity, on day 8 of pressure overload. These data are compatible with the hypothesis that increases in locally produced ET-1 and the density of ET-1 binding sites have an important relationship with the development of cardiac hypertrophy in vivo.(ABSTRACT TRUNCATED AT 250 WORDS)

[Renal function after TKR in patients with rheumatoid arthritis who have chronic renal insufficiency]

Twenty three patients with RA who have chronic renal insufficiency were post operatively studied for changes in the renal function with TKR (total knee replacement). We evaluated the renal function by BUN, Creatine, PSP and Creatine clearance. The renal function has not grown worse in all cases. TKR is a safe operation for renal function with careful technique and management.

An amino-terminal fibronectin fragment stimulates the differentiation of ST-13 preadipocytes

Differentiation of ST-13 preadipocytes into adipocytes was inhibited almost completely by addition of rat plasma fibronectin (FN) (approximately 100 micrograms/mL), but was reversed by GRGDSP cell recognition peptide (1.5 mM) and anti-alpha 5 beta 1. On the contrary, the thermolysin digest of FN stimulated adipocyte differentiation in a dose-dependent manner, in which remarkable increases in the values of the differentiation indexes, the number of adipocytes (8-fold above the control), glycerophosphate dehydrogenase (GPD) activity (12-fold), and triacylglycerol content (5-fold), were observed by inclusion of the thermolysin digest (100 micrograms/mL). The increase in GPD activity by the thermolysin digest was inhibited remarkably (about 70% inhibition) by an antibody directed to the amino-terminal fibrin-binding (Fib 1) domain of FN and slightly (about 15%) by an antibody directed to the central cell-binding (Cell) domain, but not by anti-gelatin-binding domain and anti-carboxy-terminal fibrin-binding domain. Treatment of ST-13 cells by a purified 24K fragment (100 micrograms/mL) derived from the Fib 1 domain caused an over 20-fold augmentation of the GPD activity, accounting for a major part of the differentiation stimulatory activity of the thermolysin digest. The differentiation stimulatory effect of the 24K Fib 1 fragment was not affected by either GRGDSP peptide or anti-alpha 5 beta 1. Thus, FN can regulate adipose development of ST-13 cells by its two antipodal, inhibitory and stimulatory, activities, the latter of which is expressed only upon fragmentation. Proteolytic cleavage of FN may play an important role in controlling the action of FN on adipocyte differentiation.

Stimulation of the protein synthesis by fibronectin is specific for untransformed fibroblastic cells

In the preceding paper, we showed that fibronectin (FN) in solution has the ability to stimulate protein synthesis in NIH-L1 fibroblastic cells. We show here that FN stimulated protein synthesis also in other normal fibroblast cell lines, WI-38 and BALB/3T3, but did so only slightly in their transformed cell lines, L1-4NQOH10, WI-38 VA-13 and KN(7)8; and in rat hepatocytes in primary culture and rat liver epidermoid cells (GR-1) it hardly affected the synthesis. Augmentation of the protein synthesis rate was not attributable to stimulation of collagen synthesis. This stimulatory activity of FN was enhanced remarkably by proteolytic digestion of FN with trypsin.

Antihypertensive effect of a novel calcium antagonist, SD-3211, in experimental hypertensive rats

The antihypertensive effect of SD-3211, a structurally novel type of nondihydropyridine calcium antagonist, was assessed using several types of experimental hypertensive rats. Oral administration of SD-3211 (10, 20, and 30 mg/kg) to conscious spontaneously hypertensive rats (SHR), deoxycorticosterone acetate-salt hypertensive rats (DHR) and 2-kidney, 1-clip renal hypertensive rats (RHR) resulted in a dose-dependent decrease in systolic blood pressure (SBP). The hypotensive effect of SD-3211 in these hypertensive rats was more pronounced than in normotensive rats (NR). The potencies of SD-3211 for the hypotensive effect in the hypertensive rats and NR were 5-7 times greater than that of diltiazem but 2-3 times less than that of nicardipine. Furthermore, SD-3211 showed longer-lasting hypotensive action than diltiazem and nicardipine, at the respective equihypotensive dose. During the course of hypotension, SD-3211 did not exert any influence on heart rate (HR) in any type of hypertensive rats or NR, in contrast to the appearance of tachycardia with nicardipine in SHR, DHR, and NR and of bradycardia with diltiazem in DHR. At doses of 10 and 30 mg/kg, the hypotensive doses, SD-3211 elicited a dose-dependent natriuresis but no kaliuresis in SHR. In the chronic study using SHR, SD-3211 at 10 mg/kg/day showed an antihypertensive effect during an administration period of 12 consecutive weeks. These results allow us to conclude that SD-3211 has a potent and long-lasting hypotensive action with little cardiac effect.

Cardiovascular characterization of SD-3211, a novel benzothiazine calcium channel blocker, in isolated rabbit hearts

The cardiovascular effects of SD-3211, a novel benzothiazine Ca++ channel blocker, were compared with those of diltiazem and nicardipine in Langendorff-perfused rabbit hearts. SD-3211 was more potent in increasing coronary artery flow than in depressing cardiac function (i.e., contractile force, heart rate and conduction time). The relative specificity of SD-3211 for coronary vasodilation to cardiodepression was clearly greater than that of diltiazem, but less than that of nicardipine. Thus, the present study demonstrates that SD-3211, despite a non-dihydropyridine type of Ca++ channel blocker, can be characterized as a potent coronary vasodilator with a little effect on cardiac function.

Cardiohemodynamic effect of a novel calcium antagonist, SD-3211, in the dog

The cardiohemodynamic effects of SD-3211, a calcium antagonist possessing a unique structure, were studied in anesthetized open-chest dogs and in conscious dogs. SD-3211 (10-300 micrograms/kg, i.v.) increased coronary and vertebral artery blood flow dose-dependently while lowering blood pressure, indicating a vasodilatation of these arteries. SD-3211 caused a significant increase in heart rate at 10-100 micrograms/kg, but a significant decrease at 300 micrograms/kg. Left ventricular dp dtmax was dose-dependently decreased at the dose range examined, and the change was significant at 300 micrograms/kg. When compared with the cardiohemodynamic effects of diltiazem (10 300 micrograms/kg, i.v.) and nicardipine (1-30 micrograms/kg, i.v.), the selectivity of SD-3211 with regard to vasodilatation as compared to cardiac depression, manifested by a reduction in heart rate and myocardial contractility, was greater than that of diltiazem, but less than that of nicardipine. Furthermore, a comparative study of the effects of orally administered SD-3211 and diltiazem on blood pressure and atrioventricular conduction in conscious, normotensive dogs, demonstrated that SD-3211 had a more potent and long-lasting hypotensive effect, but a much weaker effect on atrioventricular conduction prolongation than diltiazem. Thus, these in vivo cardiohemodynamic studies show that SD-3211 possesses a tissue-selectivity for vasculature, respectively cardiac tissues, which is intermediate between diltiazem and nicardipine.

Electrophysiological properties of SD-3211, a novel putative Ca2+ antagonist, in isolated guinea pig and rabbit hearts

The cardiac effects of SD-3211, a novel non-dihydropyridine type of Ca2+ antagonist, were examined in isolated guinea pig and rabbit hearts using an electrophysiological technique. SD-3211 (10(-6)-10(-5) M) shortened the action potential duration of guinea pig papillary muscles in a concentration-dependent manner without affecting the resting potential or the maximum upstroke velocity (Vmax). The Vmax of slow responses induced by high extracellular K+ and isoproterenol was inhibited by SD-3211 at concentrations of greater than 10(-6) M. Elevation of extracellular Ca2+ by 2 mM reversed this inhibited response. The inhibitory effect of SD-3211 on the slow response was enhanced as the stimulation frequency was increased. In Langendorff-perfused rabbit hearts electrically driven at 2.0 Hz, SD-3211 (10(-8)-10(-6) M) produced a concentration-dependent prolongation of the atrium-His bundle conduction time (A-H interval) as well as a reduction in the developed tension of ventricular muscle, whereas SD-3211 did not affect the His bundle-ventricular conduction time (H-V interval) significantly. The potency of SD-3211 in A-H prolongation was greater than those of diltiazem and bepridil, but weaker than those of nicardipine, nifedipine, and verapamil. The effect of SD-3211 on the A-H interval was more pronounced at higher stimulation frequencies. SD-3211 was intermediate between nicardipine and verapamil in its intensity of frequency-dependent effects on the A-H interval. These results suggest that SD-3211 has a preferential and frequency-dependent inhibitory action on cardiac slow Ca2+ channels.

Synthesis and calcium antagonistic activity of (+)-(R)- and (-)-(S)-3-acetyl-2-[5-methoxy-2-[4-[N-methyl-N-(3,4,5- trimethoxyphenethyl)amino]butoxy]phenyl]benzothiazoline hydrochloride

SA2572 ((+)-1), 3-acetyl-2-[5-methoxy-2-[4-[N-methyl-N-(3,4,5-trimethoxyphenethyl) amino] butoxy]phenyl]-benzothiazoline hydrochloride is a newly synthesized Ca2+ antagonist having a inhibitory effect on the fast Na+ inward channel. In order to clarify the absolute configurations and the pharmacological properties of both enantiomers, compounds ((+)-1 and (-)-1) were synthesized. The configurations of these compounds were assigned on the basis of an X-ray crystallographic analysis of synthetic precursor (5). The in vitro Ca2+ channel blocking activities of (+)-1 and (-)-1 were evaluated in terms of the inhibitory activities on depolarization-induced contraction of guinea pig taenia cecum and rabbit aorta. The in vivo efficacy of the enantiomers was evaluated with their hypotensive effects in spontaneously hypertensive rats. Compound (-)-1 showed more potent Ca2+ antagonistic activities on guinea pig taenia cecum and rabbit aorta and the hypotensive effect than those activities of (+)-1. In the electrophysiological study of Langendorff perfused rabbit hearts, compound (+)-1 showed more potent inhibitory effect on the fast Na+ inward channel than that of compound (-)-1, and an approximately equal potent inhibitory effect on the slow Ca2+ inward channel as compared with compound (-)-1. Stereoselectivity of the pharmacological activity was found.

Effect of tiopronin on prostaglandin synthesis in rabbit kidney medulla slices

The effect of 2-mercaptopropionylglycine (tiopronin), which is widely used for the treatment of various hepatic disorders, on the generation of medullary prostaglandins (PG) E2 and F2 alpha has been examined. Tiopronin had a potent inhibitory effect on PG E2 formation. Simultaneously, PG F2 alpha production was increased. In the presence of tiopronin the net increased amount of PG F2 alpha was much smaller than the net decreased amount of PG E2 (6-20%). These results suggest that tiopronin has the potential to modulate PG E2 and F2 alpha synthesis by affecting endoperoxide E2 isomerase or endoperoxide reductase and that this effect may represent some pharmacological action of the drug.

Novel calcium antagonists. Synthesis and structure-activity relationship studies of benzothiazoline derivatives

A series of novel compounds having a benzothiazoline skeleton was studied for their structure-activity relationship (SAR) with respect to Ca2+ antagonistic activity. As test compounds, analogues of 3-acyl-2-arylbenzothiazolines (3) were synthesized. Benzothiazoline derivatives (3) exerted higher Ca2+ antagonistic activity than the corresponding thiazolidine derivatives (2). Effects of substituents R1-R4, the substitution position of the aminoalkoxy group and R2, and the length of the methylene chain on biological activities were examined. Compound 4 [3-acetyl-2-[5-methoxy-2-[4-[N-methyl-N-(3,4,5-trimethoxyphenethyl ) amino]butoxy]phenyl]benzothiazoline hydrochloride] showed a potent Ca2+ antagonistic activity in vitro and dual inhibition on the fast Na+ inward channel and the slow Ca2+ inward channel in Langendorff perfused rabbit hearts. Compound 4 also showed a long-acting hypotensive effect in spontaneously hypertensive rats and prevented acute pulmonary thrombotic death in mice.

Effects of an angiotensin-converting enzyme (ACE) inhibitor, SA446, on tissue ACE activity in normotensive, spontaneously hypertensive, and renal hypertensive rats

Effects of an angiotensin-converting enzyme (ACE) inhibitor, SA446, on the renin-angiotensin system, particularly on tissue ACE activity, were studied in Wistar-Kyoto normotensive rats (WKY), spontaneously hypertensive rats (SHR), and two-kidney, one-clip renal hypertensive rats (RHR) by repeated oral administration for 7 days. SA446 (45 mg/kg/day p.o.) inhibited ACE activity in the lung, brain, kidney, heart, and whole blood throughout the administration period in WKY, but showed a slight hypotensive action and no inhibition of aorta ACE activity. On the other hand, SA446 had an apparent hypotensive action at the same dose in SHR and inhibited ACE activity significantly in the aorta as well as the kidney and whole blood during the administration period. Furthermore, enzyme activity in the aorta, kidney, heart, and whole blood was also inhibited at a hypotensive dose of SA446 (10 mg/kg/day p.o.) in RHR. The inhibition in whole blood and kidney was almost complete, and the inhibition in the aorta was greater on day 7 than on day 1. The maximum decrease of blood pressure was correlated with the maximum inhibition in aorta ACE activity, but not in brain, lung, or heart ACE activity. In addition, a good positive correlation was observed between the basal blood pressure and the basal aorta ACE activity in WKY, SHR, and RHR, although there was no correlation in the brain, lung, kidney, heart, or whole blood. These results suggest that the antihypertensive action of SA446 by repeated administration may be due to inhibition of arterial ACE activity in addition to inhibition of plasma and kidney ACE activity.(ABSTRACT TRUNCATED AT 250 WORDS)

General pharmacological properties of the potent angiotensin converting enzyme inhibitor rentiapril

Pharmacological properties of (2R,4R)-2-(o-hydroxyphenyl)-3-(3-mercaptopropionyl)-4- thiazolidinecarboxylic acid (rentiapril, SA 446), a potent inhibitor of angiotensin converting enzyme, were examined. SA 446 given intravenously lowered blood pressure in anesthetized rats and rabbits dose-dependently, while it had no remarkable effect in conscious rats even at a dose of 100 mg/kg orally or intravenously. SA 446 had no effect on heart rate in anesthetized rabbits up to 100 mg/kg i.v. In anesthetized dogs, SA 446 at a dose of 1 mg/kg i.v. produced decrease in blood pressure accompanied with coronary and vertebral arterial vasodilations, but gave no change in heart rate. SA 446 had no influence on respiration of anesthetized rabbits at doses up to 100 mg/kg i.v. The drug showed no effect on contractile force or beating rate of isolated guinea pig atria at concentrations up to 10(-4) mol/l, but caused vasoconstriction of isolated rabbit ear vessels at a 0.1 ml dose of 3 X 10(-2) mol/l solution or more and relaxation of isolated rat thoracic aortas at concentrations over 3 X 10(-4) mol/l. SA 446 had no influence on beta 1- or beta 2-adrenoceptors of isolated guinea pig atria and tracheas, respectively. Neither was a calcium antagonistic action observed. SA 446 did not influence the central nervous system, neuromuscular transmission, spontaneous movement or contractile response to several agonists of isolated smooth muscles, secretion of digestive glands, blood coagulation, hemolysis or blood glucose level, and it showed no muscle relaxant, antispasmodic or local anesthetic effect.(ABSTRACT TRUNCATED AT 250 WORDS)

Species difference of (2R,4R)-2-(o-hydroxyphenyl)-3-(3-mercaptopropionyl)-4-thiazolidinec arb oxylic acid (SA446) in inhibition of angiotensin converting enzyme

A marked species difference was observed both in vitro and in vivo in the activity of SA446, an orally active inhibitor of angiotensin converting enzyme (ACE), as compared with that of captopril in five different animal species. The activity of SA446 in vitro in inhibiting plasma ACE correlated with the activity in vivo as determined by inhibition of the pressor response to angiotensin I (AI). SA446 was more potent as an inhibitor of AI response in dogs, cats and rabbits than in guinea pigs and rats. Furthermore, ACE activity in whole blood in vivo was inhibited by SA446, and the activity of SA446 was also more potent in dogs than in rats. The concentration of SA446 in the ultrafiltrate of blood (free form) was significantly higher in dogs than in rats, while no difference was observed in level of SA446 in the whole blood (free and protein-bound form) between these two species after intravenous injection. The binding rate of SA446 to plasma protein of rats in vitro was more than twice as high as that of dogs. These results suggest that the difference in the protein binding rate of SA446 is reflected in ultrafiltrate level and is one of the important components in defining the species difference in SA446 action.

[Combined effect of (2R, 4R)-2-(o-hydroxyphenyl)-3-(3-mercaptopropionyl)-4-thiazolidinecarbo xyl ic acid (SA446) with hydrochlorothiazide or propranolol on development of hypertension in spontaneously hypertensive rats (SHR) by long-term administration]

Effect of long-term oral administration of the converting enzyme inhibitor (2R, 4R)-2-(o-hydroxyphenyl)-3-(mercaptopropionyl)-4-thiazolidinecarboxylic acid (SA446) in combination with hydrochlorothiazide or propranolol on the development of hypertension was examined in spontaneously hypertensive rats (SHR). The development of hypertension in SHR was markedly suppressed by the treatment with SA446 (45 mg/kg, p.o.) for 17 weeks from 8 weeks of age, the pre-stage of hypertension. Long-term administration of hydrochlorothiazide (20 mg/kg, p.o.) also showed an obvious antihypertensive effect, but the effect was less potent than that of SA446. On the other hand, propranolol (20 mg/kg, p.o.) showed a slight or little antihypertensive effect. The combined administration of hydrochlorothiazide and SA446 produced a more potent antihypertensive effect than the administration of SA446 alone. On the other hand, the combined use of propranolol had no influence on the antihypertensive effect of SA446 by long-term administration in SHR. Plasma renin activities measured after 17 weeks treatment of the drugs indicated that the renin-angiotensin system was activated by hydrochlorothiazide. These results suggest that the antihypertensive effect of long-term administration of SA446 in SHR is enhanced by the combined administration of diuretics such as hydrochlorothiazide, which activates the renin-angiotensin system.

Effects of sodium loading on antihypertensive responses to an angiotensin-converting enzyme inhibitor in spontaneously hypertensive and renal hypertensive rats

Sodium loading significantly attenuated the antihypertensive potency of an angiotensin-converting enzyme inhibitor, SA446, in 2-kidney, 1-clip renal hypertensive rats, but the potency of SA446 remained unchanged in spontaneously hypertensive rats. Basal levels of plasma renin activity of both types of hypertensive rats were suppressed by sodium loading. From these results, it appeared that a different mechanism was involved in the maintenance of hypertension in 2-kidney, 1-clip renal hypertensive rats and in spontaneously hypertensive rats. It also appeared that the mechanism of the antihypertensive action of angiotensin-converting enzyme inhibitors was not explainable only by the suppression of the plasma renin-angiotensin system.

[Antihypertensive effects of SA446, hydralazine and the combination on renal hypertensive rats and spontaneously hypertensive rats by long-term treatment]

SA446 [(2R, 4R)-2-(o-hydroxyphenyl)-3-(3-mercaptopropionyl)-4- thiazolidinecarboxylic acid] (30 mg/kg/day), an orally active angiotensin-converting enzyme inhibitor, lowered significantly indirect systolic blood pressure (SBP) of 2-kidney, 1-clip renal hypertensive rats (RHR) by consecutive oral administration over a 14 week period. Daily oral dosing of hydralazine (2 mg/kg/day) for 14 weeks had little or no effect on SBP, but potentiated the antihypertensive effect of SA446. One to two weeks after discontinuation of the drugs, SBP in SA446 and the combination groups returned to the control level. Survival rates were 64%, 30% in the control and hydralazine group, respectively, but no death was observed in the SA446 group and the combination group throughout the administration period. Twenty-four hour urine volume and water intake tended to increase in the hydralazine group through the administration period, but increased apparently in the SA446 group and the combination group after discontinuation of the drugs. Daily oral dosing of SA446 (45 mg/kg/day) for over 16 weeks completely prevented the development of hypertension in spontaneously hypertensive rats (SHR). Daily oral dosing of hydralazine (2 mg/kg/day) similarly prevented the development. The combined effect with SA446 and hydralazine on the development was also observed. SBP in the SA446 group and the combination group increased gradually after discontinuation of the drugs, but were maintained at a low level as compared with the control group 3 weeks after discontinuation, while hydralazine gave a rapid return. No influences were observed in 24 hr-urine volume and water intake during and after the administration period in SHR.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of immunomodulators on candidacidal activity of normal peritoneal cells in BALB/c mice

Macrophages which play an important role in host resistance against infections are considered to be a target for various immunomodulators. In order to examine the effects of selected immunomodulators on macrophage function, the effects of N-(2-mercapto-2-methylpropanoyl)-L-cysteine (SA96), levamisole (LMS) and D-penicillamine (D-Pc) on the candidacidal activity of the normal peritoneal cells (PC) were investigated. In the in vitro studies, SA96 increased the candidacidal activity of PC 4-fold, while D-Pc and LMS treatments did not increase this activity. In the ex vivo studies, PC obtained from the mice pre-treated with SA96, D-Pc and LMS showed a high candidacidal activity. Elevated candidacidal activity was not due to changes of cell types of PC populations. These results suggest that D-Pc and LMS activate the function of macrophage in vivo and SA96 activates the function both in vitro and in vivo.

[Pharmacological studies of N-(2-mercapto-2-methylpropionyl)-L-cysteine (SA 96). VI. Effects on vitamin B6, metals and skin collagen in rats]

N-(2-Mercapto-2-methylpropionyl)-L-cysteine (SA 96), an antirheumatic agent, and the main metabolite of SA 96, N-[2-methyl-2-(methylthio)propionyl]-L-cysteine (SA 679), were investigated for the effects on vitamin B6 (VB6), metals and skin collagen in rats in comparison with D-penicillamine (D-Pc). SA 96 had no effect on VB6 amount in serum and liver at doses of 30 mg/kg and 150 mg/kg, p.o., for 28 days, but SA 96 as well as SA 679 lowered the level in the liver slightly at a dose of 600 mg/kg. On the other hand, D-Pc lowered the VB6 level markedly both in serum and liver at doses of 150 mg/kg and 600 mg/kg, p.o., for 28 days. SA 96, SA 679 or D-Pc had no effect on urinary VB6 excretion. The degree of complexing of SA 96 as well as SA 679 with pyridoxal-5-phosphate in vitro was very slight as compared with D-Pc. SA 96 and D-Pc increased Cu and Zn excretion in urine, decreased Cu level both in serum and liver, and increased Zn level in serum. However, the degree of these effects of SA 96 on the metals was very slight as compared with D-Pc. SA 96 or SA 679 had no effect on skin collagen, neither soluble nor insoluble collagen, but D-Pc increased soluble collagen markedly. In addition, at a dose of 600 mg/kg, D-Pc decreased insoluble collagen.(ABSTRACT TRUNCATED AT 250 WORDS)

[Pharmacological studies of N-(2-mercapto-2-methylpropanoyl)-L-cysteine (SA96). V. Effects of SA96 in combination with indomethacin or prednisolone on adjuvant arthritis in rats]

SA96 in combination with indomethacin or prednisolone was investigated for their effects on the adjuvant arthritis in Lewis rats. SA96 given orally at a dose of 10 mg/kg inhibited the inflammation of adjuvant treated foot and untreated foot and the increase of serum Cu concentration which followed the development of adjuvant arthritis, but 2 mg/kg had no effect. Indomethacin given orally at a dose of 0.1 mg/kg or prednisolone given orally at a dose of 0.4 mg/kg also inhibited the adjuvant arthritis. Prednisolone suppressed the decrease of A/G ratio. Indomethacin and prednisolone, however, had no effects on the increase of serum Cu concentration. SA96 at a dose of 10 mg/kg in combination with indomethacin was more effective than the treatment of each drug alone on inflammation of adjuvant treated and untreated foot, serum Cu concentration, erythrocyte sedimentation rate and A/G ratio. The combination of SA96 at a dose of 2 mg/kg or 10 mg/kg with prednisolone had similar synergistic effects towards the adjuvant arthritis in rats.

[Pharmacological studies on N-(2-mercapto-2-methylpropanoyl)-L-cysteine(SA96). IV. Effects of SA96 and its main metabolite, SA679, on denaturation of human gamma-globulin and adjuvant arthritis in rats]

SA96 and its main metabolite, SA679, were investigated for their effects on denaturation of human gamma-globulin and bovine serum albumin (BSA) and on adjuvant arthritis in Lewis rats. The heat denaturation of human gamma-globulin and BSA enhanced by Cu2+ was inhibited by SA96, SA679 and D-penicillamine, and the inhibitory effect of SA96 was the most potent. In adjuvant arthritis rats, SA96 given orally at a dose of 10 mg/kg from the same day as the adjuvant injection inhibited significantly the swelling of adjuvant treated foot and untreated foot, increase of the relative organ weights of the adrenals, liver and kidney, and increase of serum Cu concentration; but at a dose of 100 mg/kg, it did not show any effects on these parameters. On the other hand, SA96 given from three days before the adjuvant injection showed the inhibitory effects at a dose of 100 mg/kg as well as 10 mg/kg. These results suggest that the effect of SA96 on adjuvant arthritis in rats depends on its administration schedule. SA679 also inhibited the adjuvant arthritis at a dose of 100 mg/kg, but its effect was less potent than that of SA96.

Pharmacological studies of N-(2-mercapto-2-methylpropanoyl)-L-cysteine (SA96) (3). Effects of SA96 on experimental allergic reactions

The effects of an antirheumatic agent, N-(2-mercapto-2-methylpropanoyl)-L-cysteine (SA96), were investigated on allergic reactions in rats and guinea pigs. The effects of SA96 were compared with those of D-penicillamine (D-Pc). SA96 given twice orally at the doses of 10 to 50 mg/kg significantly caused inhibitions of 28%, 29% and 44% against passive cutaneous anaphylaxis (PCA), reversed cutaneous anaphylaxis (RCA) and reversed passive Arthus (RPA) reactions, which are classified as Type I, Type II and Type III allergic reactions, respectively. D-Pc also showed inhibitions of 30%, 23% and 18% on Type I, Type II and Type III reactions, respectively, and inhibitions on Type II and Type III reactions were not significant. On the other hand, SA96 (10 to 50 mg/kg twice) had no influence on the Type IV allergic reaction, delayed hypersensitivity, while D-Pc (20 mg/kg twice) showed an enhancement of 27% on the Type IV reaction. In the in vitro study, SA96 inhibited the hemolytic complement activity at 10(-4) to 10(-2) M and the macrophage migration at 1 X 10(-4) to 5 X 10(-3) M in a dose-dependent manner. These in vitro activities of SA96 were more potent than those of D-Pc. These results showed that SA96 had some different immunopharmacological properties on experimental allergic reactions as compared with those of D-Pc.

Potentiative effect of angiotensin converting enzyme inhibitor on carrageenan edema in rats and the role of tissue kininogen

Roles of kininogens in the development of potentiation of carrageenan edema in rats by angiotensin converting enzyme (ACE, = kininase II) inhibitor were studied. Carrageenan-induced edema was potentiated by oral administration of YS980, an ACE inhibitor, at a dose of 1 mg/kg 0.5 h before carrageenan injection. Intravenous injection of bromelain, a kininogen (KGN) depletor, at 3 mg/kg produced reduction of plasma KGN (total and high molecular weight KGN), which resulted in suppression of carrageenan edema and suppression of edema potentiation induced by YS980. Even after the plasma KGN level and inflammatory response to carrageenan returned to normal 24 h after the administration of bromelain, the potentiative effect of YS980 on the carrageenan edema remained suppressed. Thus, some factor other than plasma KGN is thought to be involved in the potentiation mechanisms on the carrageenan edema by YS980. Partially purified KGN from rat plasma (0.1 mg/site: liberated 4.4 X 10(-8) g bradykinin eq by trypsin digestion) completely restored the suppressed potentiation to normal by local preinjection to the inflamed site. In addition, such restoration was not observed in the animal in which plasma KGN was reduced 3 h after administration of bromelain. These results suggest that KGN, not only in plasma but also in tissue, play an active role in the development of potentiation of carrageenan edema by ACE inhibitor.

Renal excretion of an angiotensin I converting enzyme inhibitor (SA-446) in dogs

The renal excretory mechanism of an orally active inhibitor of angiotensin converting enzyme (SA-446) was examined in anesthetized dogs. Parenteral administration of this compound resulted in production of constant levels of about 2 mg/l in the plasma (PSA) and the urine concentration was 726 +/- 200 mg/l, a level significantly higher than that in the plasma. Renal clearance of SA-446 (CSA) was 2.24 +/- 0.34 ml/g X min and was significantly higher than GFR. The clearance ratio (CSA/GFR) of over 1.0 was indicative of a net tubular secretion. Administration of probenecid resulted in a significant rise in PSA and in a significant decrease in urinary excretion but with no change in the plasma protein binding ratio. CSA decreased significantly from 2.24 +/- 0.34 to 0.71 +/- 0.14 ml/g X min. The inhibitory action of SA-446 (0.02 mg/kg, i.v.) on the pressor response to angiotensin I disappeared at about 50 min, this action being maintained for about 2 h in the probenecid pretreated dog. Since probenecid is a competitive inhibitor of organic anion secretory transport, our results show the net tubular secretion of SA-446, via organic anion transport systems. Prolongation of the action of SA-446, as induced by probenecid may be due to the increase of plasma concentration, by the inhibition of tubular secretion.