In vitro and in vivo K channel-opening effects of Ki3315, a metabolite of the novel vasodilator KRN2391

The vasodilating potencies and mechanism of action of KRN2391 [N-cyano-N'-(2-nitroxyethyl)-3-pyridinecarboximidamide monomethanesulfonate] and its metabolite Ki3315 [N-cyano-N'-(2-hydroxyethyl)-3-pyridinecarboximidamide] were investigated in rat isolated aortae and in pithed rats. In experiments using rat isolated aortae, Ki3315 (10(-5)-3 x 10(-4) M) and KRN2391 (10(-8)-10(-4) M) produced concentration-dependent relaxations. However, the vasodilating potency of Ki3315 was about 1000-fold lower than that of KRN2391. The relaxant effect of KRN2391 was antagonized by both methylene blue and glibenclamide, whereas that of Ki3315 was only antagonized by glibenclamide. In experiments using pithed rats, cumulative administration of Ki3315 (0.3-30 mg/kg, i.v.) and KRN2391 (3-300 micrograms/kg, i.v.) produced a dose-dependent decrease of diastolic blood pressure. The vasodepressor effect of Ki3315 was weaker than that of KRN2391. In rats given glibenclamide (20 mg/kg, i.v.), the vasodepressor curves for Ki3315 and KRN2391 were shifted to the right. The ED50mmHg values increased about 5-fold for KRN2391 and 8.2-fold for Ki3315 in glibenclamide-treated rats. These results suggest that Ki3315 and KRN2391 show vasorelaxant effects in vitro and in vivo, but in this respect Ki3315 is weaker than KRN2391. These effects of Ki3315 are predominantly due to a K channel-opening action, while those of KRN2391 involve a nitrate action in addition to a K channel-opening action.

Mechanism of action of KRN2391 in canine coronary vascular bed

The present studies were performed to clarify the mechanism of action of KRN2391 in various sizes of canine coronary artery. We used the responses of isolated large and small coronary arteries and the changes in coronary blood flow (CBF) as indicators reflecting the responses of conductive arteries and resistive arterioles, respectively. In isolated small coronary artery, the effect of KRN2391 (10(-8)-10(-5) M) was antagonized by either methylene blue or glibenclamide. In isolated large coronary artery, the vasorelaxant effect of KRN2391 (10(-8)-10(-5) M) and nicorandil (10(-7)-10(-4) M) were antagonized by methylene blue (10(-5) M) but not by glibenclamide (10(-6) M). The relaxant effect of cromakalim was antagonized by glibenclamide but not by methylene blue in isolated large coronary artery. Intracoronary arterial injection of KRN2391, nicorandil or cromakalim produced an increase in CBF dose-dependently. Glibenclamide (5 mg/kg, i.v.) attenuated the increase in CBF caused by KRN2391, nicorandil and cromakalim. ED20, the dose that produced an increase in CBF by 20 ml/min, increased about 5-fold for KRN2391 and nicorandil and about 12-fold for cromakalim after administration of glibenclamide. These results suggest that the mechanism of action of KRN2391 and nicorandil depends on the segment of coronary arteries; i.e., they show a nitrate action alone in large coronary artery, and a K-channel opening action in addition to a nitrate action as the size of the coronary artery decreases.

Pharmacological analysis of the vasodepressor effect of KRN2391 in pithed rats

1. The antagonism by glibenclamide of the vasodepressor effects of KRN2391, cromakalim and nitroglycerin was compared in pithed rats with blood pressure supported by an infusion of phenylephrine. 2. Cumulative administration of KRN2391 (3-300 micrograms/kg, i.v.), cromakalim (3-300 micrograms/kg, i.v.) and nitroglycerin (1-300 micrograms/kg, i.v.) produced dose-dependent decreases in diastolic blood pressure. 3. In rats given glibenclamide (20 mg/kg, i.v.) the dose-vasodepressor curves for KRN2391 and cromakalim were shifted to the right. However, glibenclamide had no effect on the vasodepressor effect of nitroglycerin. 4. The ED50mmHg values increased about 5.9 fold for KRN2391 and 9.5 fold for cromakalim in glibenclamide-treated rats. 5. These results suggest that the vasodepressor effect of KRN2391 is due to both glibenclamide-sensitive and insensitive mechanisms. This glibenclamide-insensitive effect of KRN2391 is thought to reflect its nitrate action.

Vasorelaxant action of Ki1769, a new pyridinecarboximidamide, in isolated porcine coronary artery

The characteristics of KRN2391 (N-cyano-N'-(2-nitroxyethyl)-3-pyridinecarboximidamide monomethansulfonate) and its phenethyl and 2-hydroxyethyl derivatives (Ki1769 and Ki3315) were studied in isolated porcine coronary arteries. KRN2391, Ki1769 and Ki3315 produced concentration-dependent relaxation of coronary arteries contracted by 25 mM KCl and the order of relaxant potency was KRN2391 > Ki1769 > Ki3315. At the maximum effect, KRN2391 produced nearly complete relaxation but Ki1769 produced about 66% relaxation. The maximum effect of Ki3315 could not be obtained because of its solubility. The relaxation induced by KRN2391 was antagonized by glibenclamide and methylene blue but relaxations caused by Ki1769 and Ki3315 were antagonized by glibenclamide alone. The antagonistic effect of glibenclamide on Ki1769- and Ki3315-induced relaxations was more potent than that on KRN2391-induced relaxation. KRN2391 induced relaxation of coronary arteries contracted by 40 mM KCl in a concentration-dependent manner but the effect of KRN2391 was smaller against 40 mM KCl-induced contractions than against 25 mM KCl-induced contractions. Ki1769 had almost no effect on coronary arteries contracted by 40 mM KCl. These results suggest that pyridinecarboximidamide derivatives which do not possess a nitroxyl group have vasodilating ability based on a K+ channel opening action.

Hypouricemic effect of the novel xanthine oxidase inhibitor, TEI-6720, in rodents

We investigated the xanthine oxidase/xanthine dehydrogenase inhibitory activity and hypouricemic effect of a newly synthesized xanthine oxidase/xanthine dehydrogenase inhibitor, TEI-6720, 2-(3-cyano-4-isobutoxyphenyl)-4-methyl-5-thiazole-carboxylic acid, and compared its effects with those of allopurinol in rodents. TEI-6720 was found to inhibit bovine milk xanthine oxidase, and mouse liver and rat liver xanthine oxidase/xanthine dehydrogenase with IC50 values of 1.4, 1.8 and 2.2 nM, respectively. On bovine milk xanthine oxidase, TEI-6720 exhibited mixed-type inhibition and the Ki value was 0.7 nM. TEI-6720 displayed prolonged urate-lowering activity in normal mice and rats. We evaluated the hypouricemic effect of TEI-6720 on hyperuricemia induced by the uricase inhibitor, potassium oxonate (250 mg/kg s.c., 1 h before the test drugs), and measured the total molarity of both serum allantoin and urate in rats. Oral TEI-6720 and allopurinol had a hypouricemic effect 2 h after their administration to oxonate-pretreated rats with ED50 values of 1.5 and 5.0 mg/kg, respectively. Both compounds also reduced the combined molarity of uric acid and allantoin in rats. The ED50 values of TEI-6720 and allopurinol were 2.1 and 6.9 mg/kg p.o., respectively. These results suggest that TEI-6720 may be useful for the treatment of hyperuricemia.

Effect of KRN2391, a novel vasodilator, on various experimental anginal models in rats

The antianginal effect of KRN2391, N-cyano-N'-(2-nitroxyethyl)-3-pyridinecarboximidamide monomethanesulfonate, on various anginal models in rats was compared with those of nifedipine and nicorandil. Angina pectoris was induced by methacholine or isoproterenol, and the change in the ST-segments in the electrocardiogram (ECG) was used as the parameter to indicate angina pectoris. The intracoronary administration of methacholine (3 micrograms) produced an elevation in the ST-segment of the ECG. This ST-elevation was inhibited by the intravenous administration of KRN2391 (30 and 100 micrograms/kg), nifedipine (100 and 300 micrograms/kg) and nicorandil (1000 and 3000 micrograms/kg). The administration of isoproterenol (10 micrograms/kg/min, i.v.) produced a depression of the ST-segment of the ECG. The intravenous administration of KRN2391 (100 micrograms/kg), nifedipine (100 micrograms/kg) and nicorandil (3000 micrograms/kg) inhibited the ECG changes induced by isoproterenol. These results suggest that KRN2391 exerts a potent protective effect on angina pectoris models compared with nifedipine and nicorandil. KRN2391 appears to be useful as an antianginal drug.

Effects of KRN2391, nicorandil and diltiazem on the changes in the electrocardiogram caused by endothelin-1 in anaesthetized rats

1. The effect of KRN2391, a novel vasodilator, on the changes of electrocardiogram caused by endothelin-1 (ET-1) was studied in anaesthetized rats and compared with the effects of nicorandil and diltiazem. In addition, the effect of KRN2391 on the action potential of guinea-pig papillary muscle was studied. 2. The intracoronary administration (i.c.) of ET-1 (5 micrograms) induced not only ST segment elevation of the electrocardiogram due to contraction of the coronary artery, but also arrhythmias involving atrioventricular block (A-V block), ventricular premature contraction (VPC) and ventricular fibrillation (VF), and resulted in death in most animals. However, the administration of methacholine (3 micrograms, i.c.) produced ST segment elevation alone without developing arrhythmias. 3. Pretreatment with intravenous administration of KRN2391 (30 micrograms kg-1) inhibited the ST segment elevation and the development of arrhythmias induced by ET-1, and decreased the incidence of death. 4. Nicorandil (1000 micrograms kg-1) prevented the ST segment elevation without suppression of the occurrence of VF. Diltiazem (100 micrograms kg-1) suppressed both the ST segment elevation and the occurrence of VF but not other arrhythmias. Nicorandil at 3000 micrograms kg-1 and diltiazem at 300 micrograms kg-1 produced not only a suppression of ST segment elevation and VF incidence but also a decrease in the occurrence of arrhythmias. These doses of nicorandil and diltiazem produced a decrease in death in a dose-dependent manner. 5. KRN2391 (10 and 30 micrograms kg-1), nicorandil (1000 and 3000 micrograms kg-1) and diltiazem (100 and 300 micrograms kg-1) significantly decreased mean blood pressure in a dose-dependent manner. Heart rate was decreased by nicorandil (3000 microg kg-1) and diltiazem (100 and 300 microg kg-1) but was not affected byKRN2391 (10 and 30 microg kg-1).6. KRN2391 (30 microM) significantly shortened the action potential duration of guinea-pig ventricle at 50% and 90% repolarization (APD50 and APD90). The effect of KRN2391 was inhibited by a K+channel blocker, glibenclamide (30 microM).7. These results suggest that the occurrence of ST segment elevation and arrhythmias induced by ET-1 are due to a dual direct action on both coronary vascular smooth muscle and myocardium. Therefore,the protective effects of KRN2391, nicorandil and diltiazem on ET-l-induced heart disorders appear to be due to their direct actions on coronary vascular smooth muscle and the myocardium.

Effect of KRN2391 on venous return: comparison with other vasodilators

We compared the cardiohemodynamic effects of KRN2391, a novel coronary vasodilator, with those of nicorandil, nifedipine, cromakalim, and nitroglycerin (NTG) administered intravenously (i.v.) to anesthetized open-chest dogs. KRN2391 (10 and 30 micrograms/kg) decreased mean blood pressure (MBP) and superior vena cava flow (SVCF), and increased inferior vena cava flow (IVCF), total venous return (TVR), pulmonary artery blood flow (PAF), and right atrial pressure (RAP). Administration of KRN2391 (30 micrograms/kg) decreased heart rate (HR). Nicorandil (100 and 300 micrograms/kg) decreased MBP and SVCF, and produced transient increases followed by decreases in IVCF, TVR, PAF, and RAP. HR was decreased by administration of nicorandil (300 micrograms/kg). Nifedipine (1 and 3 micrograms/kg) decreased MBP and increased SVCF, IVCF, TVR, PAF, and RAP. HR was not affected by either dose of nifedipine. Cromakalim (10 micrograms/kg) decreased MBP, SVCF, and increased HR, IVCF, TVR, PAF and RAP. Nitroglycerin (3 micrograms/kg) decreased MBP, SVCF, IVCF, TVR, PAF, and RAP. In dogs that received glibenclamide (5 mg/kg, i.v.), the changes in MBP, SVCF, IVCF, TVR, PAF, and RAP caused by KRN2391 were reduced in comparison with those in dogs that received vehicle for glibenclamide. The decreases in IVCF, TVR, and PAF induced by nicorandil were not affected by glibenclamide, but the decrease in MBP was diminished and the decrease in RAP was augmented. The hemodynamic changes caused by cromakalim were almost inhibited by glibenclamide, whereas those caused by NTG were not affected.(ABSTRACT TRUNCATED AT 250 WORDS)

Vasorelaxant mechanism of KRN2391 and nicorandil in porcine coronary arteries of different sizes

1. The relaxant mechanisms of action of KRN2391, a novel vasodilator, and nicorandil on epimyocardial coronary artery (2.5- 3.0 mm outer diameter) and mid-myocardial coronary artery (0.8-1.0 mm outer diameter) were investigated in porcine isolated coronary arteries. In addition, the vasorelaxant responses of KRN2391 and nicorandil were compared with those of nitroglycerin and cromakalim, a K+ channel opener, in epi- and mid-myocardial coronary arteries. 2. Nitroglycerin showed a more potent relaxant effect on epi-myocardial coronary arteries than on mid-myocardial coronary arteries, whereas cromakalim produced greater relaxation responses in mid-myocardial coronary arteries. There was no difference between epi- and mid-myocardial coronary arteries in terms of the relaxant effect of KRN2391 and nicorandil. 3. Relaxation induced by KRN2391 in epi- and mid-myocardial coronary arteries was inhibited by oxyhaemoglobin, a pharmacological antagonist of nitrovasodilators, and glibenclamide, a pharmacological antagonist of K+ channel opening drugs. However, the inhibitory effect of glibenclamide on KRN2391-induced relaxation was greater in mid-myocardial coronary artery than in epi-myocardial coronary artery. 4. Relaxation induced by nicorandil was inhibited by oxyhaemoglobin alone in epi-myocardial coronary arteries and by both oxyhaemoglobin and glibenclamide in mid-myocardial coronary arteries. 5. In epi- and mid-myocardial coronary arteries, relaxation induced by cromakalim was inhibited by glibenclamide but not by oxyhaemoglobin, whereas relaxation induced by nitroglycerin was inhibited by oxyhaemoglobin but not by glibenclamide. 6. These results suggest that KRN2391 and nicorandil exhibit a dual mechanism of action acting partly as a nitrate and partly as a K+ channel opener. The mechanism of action of these drugs depend on the segment of coronary artery studied. Furthermore, the dual mechanism of action of KRN2391 and nicorandil seems to contribute to the equipotent relaxant effect between epi- and mid-myocardial coronary arteries.

Characterization of Yersinia pseudotuberculosis serogroups O9, O10 and O11; subdivision of O1 serogroup into O1a, O1b, and O1c subgroups

In this study, three new antigens (O9, O10 and O11) of Yersinia pseudotuberculosis are described. The O1 antigen is further subdivided into O1a, O1b and O1c. The methods used to prepare specific antisera for O-antigen identification are also described. Furthermore, the H antigens of these new serogroups are determined and their biochemical characteristics analysed. The antigenic formulae of the known serogroups within the basic antigenic scheme introduced by the authors' laboratories are presented.

Hemodynamic profile of KRN2391, a novel vasodilator, in anesthetized dogs

In the present study, we compared the effects of KRN2391 (N-cyano-N'-(2-nitroxyethyl)-3-pyridinecarboximidamide monomethanesulfonate), a novel vasodilator, with those of nicorandil and nifedipine on hemodynamic profiles. KRN2391 (1-30 micrograms), nicorandil (10-300 micrograms), and nifedipine (0.1-3 micrograms) increased coronary, mesenteric, renal and femoral blood flows in a dose-dependent manner when intraarterially administered. KRN2391 was approximately 18 times more potent than nicorandil and about five times less potent than nifedipine in increasing coronary blood flow. Intravenous (i.v.) administration of KRN2391, nicorandil, and nifedipine produced increases in coronary and mesenteric blood flows and decreases in these vascular resistances. Although nicorandil i.v. had no significant effect on renal blood flow (RBF), nifedipine i.v. decreased RBF whereas KRN2391 i.v. increased it. Femoral BF (FBF) decreased only at the highest i.v. dose of KRN2391 and decreased after an initial increase with nicorandil. Nifedipine i.v. had no significant effect on FBF. The effects of these three agents in increasing BF and in decreasing vascular resistance were most prominent in coronary vasculature. The duration of the effect of KRN2391 in increasing coronary BF (CBF) was longer than that of nicorandil but was similar to that of nifedipine. The hypotensive effect of KRN2391 was also weaker than its effect in increasing CBF in comparison with nicorandil and nifedipine. Thus, KRN2391 was demonstrated to possess a preferential activity on coronary vasculature.

Differentiation of Yersinia enterocolitica serotype O:5,27 strains by phenotypic and molecular techniques

Restriction endonuclease analyses of virulence plasmid DNA (REAP) and chromosomal DNA and other phenotypic characteristics were used to study the differentiation of Yersinia enterocolitica serotype O:5,27 strains. There was a close correlation between REAP patterns and the geographical distribution of serotype O:5,27. Human isolates produced only one REAP pattern, which was also found with isolates from pigs and dogs.

Comparison of the effects of KRN2391 and other coronary dilators on porcine isolated coronary arteries of different sizes

The present study was performed to determine whether KRN2391 (N-cyano-N'-(2-nitroxyethyl)-3-pyridinecarboximidamide monomethanesulphonate), a novel vasodilator, shows different effects on porcine isolated coronary arteries of different sizes. The vasodilating effects of KRN2391 on porcine large (2.5-3.0 mm outer diam.) and small (0.8-1.0 mm) coronary arteries were also compared with those of cromakalim, nicorandil, nifedipine, nitroglycerin and adenosine. The relaxant effects of these drugs were examined in coronary arteries contracted by 25 mM KCl. Nitroglycerin caused greater relaxation in large vessels than in small vessels. In contrast, adenosine, nifedipine and cromakalim caused greater relaxation in small vessels. However, there was no difference between large and small vessels in the relaxing effects of KRN2391 and nicorandil. These unique features of KRN2391 and nicorandil appear to be beneficial in ischaemic heart disease.

Allele frequency distribution of the D1S80 (pMCT118) locus polymorphism in the Japanese population by the polymerase chain reaction

Population studies among Japanese were carried out at the D1S80 locus by the polymerase chain reaction and subsequent analysis in agarose gel electrophoresis. A total of 58 genotypes and 25 alleles ranging from 16 to 45 repeat units were observed in a population group of 121 unrelated individuals. The alleles with 18, 24 and 30 repeat units were found to be most common. Some large alleles with more than 42 repeat units were first observed in this study. Statistical tests for Hardy-Weinberg equilibrium showed that no significant deviations could be found in this Japanese population sample. The values of the mean exclusion chance and the discriminating power (DP) were calculated to be 0.76 and 0.91, respectively. The observed heterozygosity was 0.91.

No development of tolerance to the hypotensive effect of KRN2391, a novel vasodilator containing a nitrate moiety

The present studies were performed to examine whether tolerance develops to the hypotensive effects of KRN2391, N-cyano-N'-(2-nitroxyethyl)-3-pyridinecarboximidamide monomethanesulfonate. Rats were administered KRN2391 (0.3 or 1 mg/kg, s.c.) or nitroglycerin (10 mg/kg, s.c.) three times a day for 1 to 8 days and blood pressure was then measured under anesthesia. Chronic pretreatment with nitroglycerin attenuated the decrease in blood pressure induced by i.v. nitroglycerin but not that by i.v. KRN2391. Chronic pretreatment with KRN2391 (0.3 or 1 mg/kg, s.c.) had no effect on the decreases in blood pressure induced by i.v. nitroglycerin or i.v. KRN2391. It can be concluded that, in this rat model, no tolerance develops to the hypotensive effects of KRN2391.

Coaggregation of Prevotella intermedia with oral Actinomyces species

Five strains of Prevotella intermedia were examined for their ability to coaggregate with various gram-positive and gram-negative species of oral bacteria. Two of the P. intermedia strains coaggregated with selected Actinomyces species, P. intermedia 27 with Actinomyces viscosus T14V and Actinomyces naeslundii ATCC 12104, PK606, PK984, and PK947, and P. intermedia 113 with Actinomyces odontolyticus WVU 1546 and Actinomyces israelii WVU 838. Exposure of both Prevotella strains but not the Actinomyces strains to heat, trypsin, or proteinase K abolished most coaggregations. All pairs were disaggregated by the addition of sodium dodecyl sulfate, but only those coaggregations involving P. intermedia 113 were reversed by the addition of 2.0 M urea. P. intermedia 27 was sensitive to periodate oxidation, whereas the partner strains were stable to this treatment. Most coaggregations occurred in the presence of saliva; however, reactions involving P. intermedia 27 were not as strong as those of buffer-suspended cells. Treatment of both P. intermedia 113 coaggregations pairs with proteinase K and the results obtained from suspensions of these pairs in saliva suggest that different surface molecules of this P. intermedia strain may mediate each of these coaggregations. These data suggest that all of these coaggregations involve either a protein or glycoprotein on the Prevotella strain, which may interact with carbohydrates or carbohydrate-containing molecules on the surface of the Actinomyces strain.

Mechanism of action of KRN2391, a novel vasodilator, in canine mesenteric artery

The present study was performed to clarify the mechanism of vasodilation of KRN2391 in canine mesenteric artery compared with those of nicorandil and cromakalim. We used the responses of isolated cranial mesenteric artery in vitro and changes in mesenteric blood flow in vivo as indicators reflecting the responses of a conductive artery and resistive arterioles, respectively. In isolated cranial mesenteric artery, KRN2391 (10(-8)-10(-5) M), nicorandil (10(-7)-10(-4) M) and cromakalim (10(-7)-10(-5) M) relaxed contractions caused by 25 mM KCl in a concentration-dependent manner. The concentration-relaxation curve for KRN2391 was shifted to the right by either methylene blue (10(-5) M) or glibenclamide (10(-6) M), but the inhibitory effect of methylene blue was more potent than that of glibenclamide. The concentration-relaxation curve for nicorandil was shifted to the right by methylene blue, but not by glibenclamide. In addition, the curve for cromakalim was shifted to the right by glibenclamide, but not by methylene blue. In in vivo experiments, the injections of KRN2391 (0.3-3 micrograms/kg), nicorandil (10-100 micrograms/kg) or cromakalim (1-10 micrograms/kg) into the mesenteric artery increased mesenteric blood flow in a dose-dependent manner. Glibenclamide (5 mg/kg, i.v.) attenuated the increase in mesenteric blood flow caused by KRN2391, nicorandil and cromakalim, but had no effect on that caused by nifedipine (1 microgram/kg). The ED20 value increased about 4.7-fold for KRN2391, 3.7-fold for nicorandil and 11.5-fold for cromakalim after administration of glibenclamide, as estimated from the % change to the absolute increase in mesenteric blood flow induced by nifedipine (1 microgram/kg).(ABSTRACT TRUNCATED AT 250 WORDS)

Dissimilarity in the mechanisms of action of KRN2391, nicorandil and cromakalim in canine renal artery

In the present study, we examined the mode of action of KRN2391 (N-cyano-N'-(2-nitroxyethyl)-3-pyridinecarboximidamide monomethanesulphonate) in isolated canine renal artery compared with those of nicorandil and cromakalim. KRN2391 (10(-8)-3 x 10(-5) M), nicorandil (10(-7)-3 x 10(-4) M) and cromakalim (10(-8)-3 x 10(-5) M) relaxed renal arteries contracted by 25 mM KCl in a concentration-dependent manner. KRN2391-induced relaxation was inhibited by methylene blue (10(-5) M) and glibenclamide (10(-6) M). Nicorandil-induced relaxation was inhibited by methylene blue, but not by glibenclamide. The concentration-relaxation curve for cromakalim displayed a rightward parallel shift in the presence of glibenclamide. In the control observation, KRN2391 and nicorandil also produced full relaxation, but cromakalim did not. The present results suggest that KRN2391 acts as both a nitrate and a potassium channel opener, and nicorandil acts only as a nitrate and only in canine renal artery.

Comparison of the anti-vasoconstrictor effects of a novel vasodilator KRN2391, nicorandil and nifedipine on isolated porcine large coronary artery

The anti-vasoconstrictor profile of KRN2391, a novel vasodilator, was compared with that of nicorandil and nifedipine in isolated porcine large coronary arteries contracted by KCl, noradrenaline, serotonin, acetylcholine, endothelin-1 and U46619, a thromboxane A2 analogue. KRN2391 (10(-8) - 3 x 10(-5) M), nicorandil (10(-7) - 3 x 10(-4) M) and nifedipine (10(-10) - 10(-5) M) inhibited these contractile responses in a concentration-dependent manner. KRN2391 and nicorandil completely abolished these contractile responses at their maximum effects. However, nifedipine caused less inhibition than KRN2391 and nicorandil and did not completely abolish the contractile responses. The relaxant activity of KRN2391 was more potent than that of nicorandil. This study shows that the anti-vasoconstrictor profiles of KRN2391, nicorandil and nifedipine involve different relaxant mechanisms.

Extensive arterial calcification of unknown etiology in a 29-year-old male

A 29-year-old male with generalized arterial calcification is presented. The roentgenogram showed extensive calcification bilaterally in the facial, brachial, renal, external iliac, femoral, and popliteal arteries. There was also calcification around the joints of the fingers, toes, elbows, and shoulders. The uniformity of arterial calcification in the radiograph differentiated this lesion from Mönckeberg's arteriosclerosis. The serum concentration levels of calcium, phosphorus, alkaline phosphatase, and calcium regulatory hormones were normal. The patient did not have diabetes mellitus, renal disease, or connective tissue disease, thus the etiology of the calcification was not identified. However, a bone scintigram showed that the uptake of 99 mTc-methylene diphosphate was significantly increased in the calcified arteries. Therefore, increased metabolic activity was associated with the derangement leading to arterial calcification.

[Cardiac performance in total anomalous pulmonary venous connection]

Cardiac performance in 54 patients with total anomalous pulmonary venous connection was investigated by cardiac catheterization before and after surgery. 51 patients underwent intracardiac repair, and 17 of them died during or immediately after operation. According to the preoperative study, the left ventricular ejection fraction (LVEF) of surviving patients was significantly higher than that of patients who died, and the pulmonary arterial mean pressure of surviving patients was significantly lower than that of patients who died. However, there was no significant difference between the left ventricular end-diastolic volume (LVEDV), right ventricular ejection fraction (RVEF), and right ventricular end-diastolic volume (RVEDV) in surviving patients and those who died. Post-operative catheterization studies showed significant increases of LVEF and LVEDV compared to pre-operative figures. RVEF and RVEDV and pulmonary arterial mean pressure decreased significantly after surgery. It was concluded that preoperative cardiac performance of surviving patients was better than that of those who died, and post-operative cardiac performance of surviving patients was basically normal.

[A surgical repair of complete endocardial cushion defect associated with single atrium, persistent left superior vena cava draining into the left atrium, hemiazygos connection and double orifice mitral valve]

Successful surgical repair of a 1-year-old girl of complete endocardial cushion defect associated with single atrium, persistent left superior vena cava draining into the left atrium, hemiazygos connection and double orifice mitral valve was reported. We repaired the endocardial cushion defect by using an endocardial cushion prosthesis and a new atrial septum was created to allow the left superior vena cava draining into the right atrium. We made no treatment for the accessory mitral valve orifice because of no regurgitation.

HLA class II molecules and autoimmune hepatitis susceptibility in Japanese patients

To investigate the association between autoimmune hepatitis and HLA alleles in Japanese patients, serological typing and class II genotyping were performed using the polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLP) method. Serological typing showed that HLA-B54, -DR4, -DR53, and -DQ4 were significantly more frequent in patients with autoimmune hepatitis than in controls. HLA-DR4 was most frequently associated with autoimmune hepatitis (88.7%). In PCR-RFLP typing, the frequency of DRB1*0405 was significantly higher in autoimmune hepatitis than in controls. However, there was no significant difference in the frequency of Dw between the patients and the controls who were DR4-positive. The significant increase observed in DQA1*0301 and DQB1*0401 was explained by a linkage disequilibrium with DR4. Six DR4-negative patients had DR2, but there was no significant difference in the frequency of the DR2-associated Dw-alleles compared with the DR2-positive controls. No DPB1 allele was significantly associated with autoimmune hepatitis. These findings suggest that the basic amino acid at position 13, which is present only on the DR2 and DR4 B1 molecules (Arg on DR2 and His on DR4), contributes to the susceptibility to autoimmune hepatitis among the Japanese.