The embryonic Octamer factor 3/4 displays distinct DNA binding specificity from those of other Octamer factors

The Oct-3/4 is a transcriptional factor expressed rather specifically in inner cell mass and embryonic ectoderm during early embryogenesis in mammals. During the course of characterizing the regulatory element of embryonic transcriptional coactivator UTF1 which is one of the downstream genes of Oct-3/4, we have found that Oct-3/4, but not other Octamer factors, shows unique DNA binding specificity, being able to bind to variant Octamer sequence (5'-ACTAGCAT-3') present in UTF1 regulatory element. Here, we have determined the DNA binding property of Oct-3/4 in a systematic manner using all possible one point mutants of Octamer sequence as well as completely random sequences. These analyses led to the identification of nine distinct nucleotide sequences including the one (5'-ACTAGCAT-3') present in UTF1 regulatory element which serves rather as specific binding site for the Oct-3/4. Moreover, we show that, at least, one of the newly identified sequences, 5'-ATCAGCAT-3', exhibits a transcriptional stimulating activity equivalent to that of the variant Octamer sequence present in the UTF1 regulatory region in embryonic stem cells in a pluripotent-state specific manner.

[Surgical management of acute type A aortic dissection with a complaint of disturbance of consciousness; report of a case]

A 50-year-old female was admitted to our hospital with a chief complaint of disturbance of consciousness (DOC). Left-sided hemiparalysis was noted on examination and cerebral infarction was diagnosed with total occlusion of the right common carotid artery revealed by cerebral angiography. Pharmacological thrombolysis (urokinase 720,000 U) was performed. Dissection of the right common carotid artery was noted after successful thrombolytic therapy. Enhanced chest computed tomography (CT) showed the acute type A aortic dissection involving the cerebral artery. Ascending aortic replacement was performed 4 days after the thrombolytic therapy to avoid brain edema and hemorrhagic infarction during cardiopulmonary bypass. The postoperative course was uneventful. In the case of acute type A aortic dissection with DOC, proper indication and optimal timing of the operation may help to improve patient survival.

Identification of Sox-2 regulatory region which is under the control of Oct-3/4-Sox-2 complex

Sox-2 is a transcriptional cofactor expressed in embryonic stem (ES) cells as well as in neuronal cells. It has been demonstrated that Sox-2 plays an important role in supporting gene expression in ES cells, especially by forming a complex with embryonic Octamer factor, Oct-3/4. Here, we have analyzed the regulatory regions of the Sox-2 gene and identified two enhancers which stimulate transcription in ES cells as well as in embryonal carcinoma cells. These regulatory regions, which we termed Sox regulatory regions (SRR) 1 and 2, exert their function specifically when cells are in an undifferentiated state. Interestingly, like the regulatory elements of FGF-4 and UTF1 genes, combinatorial action of Octamer and Sox-2 binding sites support the SRR2 activity. However, biochemical analyses reveal that, due to the unique sequence and/or its organization, the SRR2 bears distinct characteristics from those of FGF-4 and UTF1 regulatory elements. That is, unlike the FGF-4 gene enhancer, the SRR2 precludes the binding of the Oct-1-Sox-2 complex. The difference between the SRR2 and UTF1 regulatory element is in the ability of SRR2 to recruit the Oct-6-Sox-2 complex as well as the Oct-3/4-Sox-2 complex. Co-transfection analyses confirm that both complexes are able to stimulate transcription through the SRR2 element.

The right retroperitoneal approach on abdominal aortic aneurysm with an isolated left-sided inferior vena cava. Report of a case

We report herein the case of a 78-year-old man found to have abdominal aortic aneurysm (AAA) with an isolated left-sided inferior vena cava (IVC). The patient was admitted to our hospital to undergo surgery for the AAA. The computed tomography revealed the sacular aneurysm of the infrarenal abdominal aorta (60 x 40 mm) and right common iliac aneurysm (30 x 30 mm). At the same time the left sided IVC was found by the CT. This IVC (13 mm wide) ascended 76 mm, dorsally to the ureter, the left side of the AAA from the right common iliac artery to the left renal artery. We performed aneurysmectomy and 20 mm knitted Dacron bifurcating graft replacement by the right retroperitoneal approach without manipulating the left-sided IVC. The procedure was completed without incident and the patient has continued to do well.

Purification and identification of the essential ionizable groups of honeybee, Apis mellifera L., trehalase

Trehalase (EC 3.2.1.28) of the bound type was purified as an electrophoretically homogeneous protein from adult honeybees by fractionation with ammonium sulfate, hydrophobic chromatography, and DEAE-Sepharose CL-6B, CM-Sepharose CL-6B, butyl-Toyopearl 650M, and p-aminophenyl beta-glucoside Sepharose 4B column chromatographies. The enzyme preparation was confirmed to be a monomeric protein containing 3.1% carbohydrate. The molecular weight was estimated to be approximately 69,000, and the optimum pH was 6.7. The Michaelis constant (Km) was 0.66 mM, and the molecular activity (k0) was 86.2 s(-1). The enzyme was an "inverting" type which produced beta-glucose from alpha, alpha-trehalose. Dependence of the V and Km values on pH gave values for the ionization constants, pKe1 and pKe2, of essential ionizable groups 1 and 2 of the free enzyme of 5.3 and 8.5, respectively. When the dielectric constant of the reaction mixture was decreased, pKe1, and pKe2 were shifted to higher values of + 0.2 and + 0.5 pH unit, respectively. The ionization heat (deltaH) of ionizable group 1 was estimated to be + 1.8 kcal/mol, and the deltaH value of group 2 was + 1.5 kcal/mol. These findings strongly support the notion that the essential ionizable groups of honeybee trehalase are two kinds of carboxyl groups, one being a dissociated type (-COO(-), ionizable group 1) and the other a protonated type (-COOH, ionizable group 2), although the pKe2 value is high.

Effects of CYP3A4 inhibition by diltiazem on pharmacokinetics and dynamics of diazepam in relation to CYP2C19 genotype status

Diazepam is metabolized by CYP2C19 and CYP3A4 in the liver. CYP2C19 shows genetic polymorphism associated with the poor metabolizer (PM) and extensive metabolizer (EM) phenotypes. The aim of this study was to assess the effect of diltiazem, a CYP3A4 inhibitor, on pharmacokinetics and dynamics of diazepam in relation to CYP2C19 genotype status. Thirteen healthy volunteers (eight EMs and five PMs) were given placebo or diltiazem (200 mg) orally for 3 days before and for 7 days after the oral 2-mg dose of diazepam in a double-blind, randomized, crossover manner. The pharmacokinetics and pharmacodynamics of diazepam were assessed with and without diltiazem. Plasma concentrations and area under the plasma concentration-time curves (AUCs) of diazepam and N-desmethyldiazepam were significantly greater in the PM compared with the EM group during the placebo phase. Diltiazem significantly increased AUC and prolonged elimination t(1/2) of diazepam in both the PM and EM groups. These pharmacokinetic changes, however, caused no significant difference in the pharmacodynamics between the two trial phases. Diltiazem affects the pharmacokinetics of diazepam in the PM and EM groups of CYP2C19. Inhibition of CYP3A4 by a concomitant substrate drug like diltiazem may cause a pharmacokinetic interaction with diazepam irrespective of CYP2C19 genotype status, but whether this interaction would reflect a pharmacodynamic change of diazepam remains unconfirmed by our study.

Significance of chymase-dependent angiotensin II-forming pathway in the development of vascular proliferation

BACKGROUND

Vascular tissues of humans and dogs contain chymase as an angiotensin II-forming enzyme. In this study, we investigated whether chymase-dependent angiotensin II formation plays a crucial role in the development of vascular proliferation in dog grafted veins.

METHODS AND RESULTS

The right external jugular vein of dogs was grafted to the ipsilateral carotid artery. As a control group, the right external jugular veins in dogs that had not received grafts were used. In the chymase inhibitor-treated group, the vein was infiltrated with 10 micromol/L Suc-Val-Pro-Phe(P)(OPh)(2) and was grafted to the carotid artery. In the placebo-treated group, ACE activity in the grafted veins was significantly lower than that in the control veins up to 7 days after the operation, whereas chymase activity was increased significantly. After 7 days, the mRNA levels of collagen I, collagen III, and fibronectin, all of which are induced by an increase of angiotensin II action, were significantly increased in the grafted veins, and the intima-media ratio of the grafted veins was also increased. In the chymase inhibitor-treated group, the chymase activity in the grafted veins 7 days after the operation was suppressed to 12.1%. The elevated mRNA levels of fibronectin, collagen I, and collagen III in the grafted veins were significantly suppressed by treatment with the chymase inhibitor, and the intima-media ratio was also decreased significantly.

CONCLUSIONS

We demonstrate for the first time that chymase-dependent angiotensin II formation plays an important role in the development of vascular proliferation in the grafted veins.

Oral administration of a specific chymase inhibitor, NK3201, inhibits vascular proliferation in grafted vein

Chymase may play an important role in vascular proliferation, as shown by in-vitro experiments, but the role of chymase in vivo has been unclear. In this study, we investigated the effect of a novel chymase inhibitor, NK3201, on this proliferation in dog grafted veins. NK3201 inhibited human and dog chymases, but not rabbit ACE. NK3201 suppressed the Ang I-induced vascular contraction in isolated dog arteries in the presence of an ACE inhibitor, and the IC50 value of chymostatin and NK3201 in dog artery was 320 nM. In dog, the concentration of NK3201 in blood was about 10 microM at 24 h after oral administration of the drug (5 mg/kg). In the group treated with NK3201, each dog was administered orally 5 mg/kg per day from 5 days before to the day before the removal of the grafted veins. Each dog underwent right common carotid artery bypass grafting with the ipsilaterial external jugular vein. By 28 days after grafting, a significant vascular proliferation was observed in the grafted veins and the chymase activity was also increased significantly. Treatment with chymase inhibitor significantly suppressed the proliferation of the grafted veins and the increased chymase activity. In this study, we demonstrate for the first time that oral administration of a specific chymase inhibitor, NK3201, appears useful for preventing vascular proliferation.

Structural analyses of the UTF1 gene encoding a transcriptional coactivator expressed in pluripotent embryonic stem cells

The UTF1 is a transcriptional coactivator expressed mainly in pluripotent embryonic stem cells. Here, we have isolated a genomic DNA fragment carrying the UTF1 gene and found that the gene contains two exons interrupted by a short intron. The gene possesses four GC boxes, but no TATA box in the 5'-flanking region. This is reminiscent of a housekeeping gene type promoter and the functional relevance of these motifs is confirmed by the transient transfection analyses. As to the gene product, our analyses have led to the identification of two different species. One of them corresponds to the full-length protein, while the other is produced by utilizing the second methionine codon for the translation initiation. The oligo-capping analyses reveal multiple transcription start sites. Interestingly, some of them are localized downstream of the first methionine codon, indicating that such transcripts produce a protein starting from the second methionine codon. Chromosomal mapping analyses locate the gene at 7F5, the syntenic region of the human chromosome (10q26) where the human UTF1 gene is located.

Purification and substrate specificity of honeybee, Apis mellifera L., alpha-glucosidase III

Alpha-glucosidase III, which was different in substrate specificity from honeybee alpha-glucosidases I and II, was purified as an electrophoretically homogeneous protein from honeybees, by salting-out chromatography, DEAE-cellulose, DEAE-Sepharose CL-6B, Bio-Gel P-150, and CM-Toyopearl 650M column chromatographies. The enzyme preparation was confirmed to be a monomeric protein and a glycoprotein containing about 7.4% of carbohydrate. The molecular weight was estimated to approximately 68,000, and the optimum pH was 5.5. The substrate specificity of alpha-glucosidase III was kinetically investigated. The enzyme did not show unusual kinetics, such as the allosteric behaviors observed in alpha-glucosidases I and II, which are monomeric proteins. The enzyme was characterized by the ability to rapidly hydrolyze sucrose, phenyl alpha-glucoside, maltose, and maltotriose, and by extremely high Km for substrates, compared with those of alpha-glucosidases I and II. Especially, maltotriose was hydrolyzed over 3 times as rapidly as maltose. However, maltooligosaccharides of four or more in the degree of polymerization were slowly degraded. The relative rates of the k0 values for maltose, sucrose, p-nitrophenyl alpha-glucoside and maltotriose were estimated to be 100, 527, 281 and 364, and the Km values for these substrates, 11, 30, 13, and 10 mM, respectively. The subsite affinities (Ai's) in the active site were tentatively evaluated from the rate parameters for maltooligosaccharides. In this enzyme, it was peculiar that the Ai value at subsite 3 was larger than that of subsite 1.

Chymase-dependent angiotensin II formation in the saphenous vein versus the internal thoracic artery

OBJECTIVES

The great saphenous vein graft is known to be less patent than the internal thoracic artery graft. Recently, we reported that chymase-dependent angiotensin II formation plays an important role in the development of intimal hyperplasia in dog grafted veins. In this study we investigated the levels of angiotensin II-forming enzymes, angiotensin-converting enzyme, and chymase in human saphenous veins and internal thoracic arteries.

METHODS

The saphenous vein and internal thoracic artery specimens were obtained from coronary artery bypass grafts of patients during surgical procedures (saphenous vein, n = 16; internal thoracic artery, n = 16). Activities of angiotensin-converting enzyme and chymase were determined by using the extract from the saphenous vein or internal thoracic artery. Sections of the saphenous vein or internal thoracic artery were stained with van Gieson's elastin stain and were immunostained with anti-human chymase antibody.

RESULTS

The activities of angiotensin-converting enzyme in the saphenous vein and internal thoracic artery were 0.34 +/- 0.12 and 0.32 +/- 0.17 mU/mg protein, respectively, and the difference was not significant. The chymase activity in the saphenous vein was significantly higher than that in the internal thoracic artery (saphenous vein, 10.1 +/- 0.81 mU/mg protein; internal thoracic artery, 6.21 +/- 1.86 mU/mg protein). Chymase-positive cells in the saphenous vein were located in both the media and adventitia, and those in the internal thoracic artery were located only in the adventitia. The number of chymase-positive cells in the saphenous vein was about 2.6 times that in the internal thoracic artery.

CONCLUSION

The chymase activity, but not the angiotensin-converting enzyme activity, was significantly higher in the saphenous vein, suggesting that the high levels of chymase activity may be related to the poorer performance of the saphenous vein for use as a bypass conduit.

Cilostazol suppresses intimal formation in dog grafted veins with reduction of angiotensin II-forming enzymes

Cilostazol prevents neointimal formation, but its mechanism has remained unclear. We investigated whether intimal formation in dog grafted veins is suppressed by cilostazol, and studied the effect of cilostazol on angiotensin II-forming enzymes. The external jugular vein was grafted to the carotid artery, and cilostazol (60 mg/kg/day) was administered orally. By 28 days after the surgery, the intimal cross-sectional area of the grafted vein was reduced to 16.7% by treatment of cilostazol, and the activities of angiotensin II-forming enzymes were suppressed significantly. The inhibitory effect of cilostazol in intimal formation may be dependent on inhibition of angiotensin II-forming enzymes.

Carbon-source-dependent transcriptional control involved in the initiation of cellular differentiation in Streptomyces griseus

Carbon source is one of the environmental factors that affects cellular differentiation of Streptomyces. We have identified the craA gene as a putative negative regulator involved in the carbon-source-dependent initiation of cellular differentiation in Streptomyces griseus. Carbon-source-dependent transcriptional repression of craA, which is caused by binding of a putative repressor protein to its promoter region, is proposed to result in the initiation of aerial mycelium formation. The presence of a craA homologue in the chromosome of Streptomyces coelicolor A3(2) implicates the existence of a similar regulatory mechanism in this organism. The repression of craA-promoter activity in glucose media could be alleviated not only by replacing glucose with maltose but also by supplying copper, which suggests that the stimulatory effect of copper on cellular differentiation in Streptomyces is excerted via abolishment of glucose-repression of craA.

Angiotensin II receptor antagonist, L-158,809, prevents intimal hyperplasia in dog grafted veins

We investigated the levels of the angiotensin II-forming enzymes, chymase and angiotensin converting enzyme (ACE), in dog grafted veins, and studied the effect of an angiotensin II type 1 receptor antagonist, L-158,809, on vascular proliferation in the grafted veins. The right external jugular vein was grafted to the ipsilaterial carotid artery. In the group treated with L-158,809, the drug (10 mg/kg per day, p.o.) were administered orally from 7 days before the operation to 28 days after it, while the others were administrated placebo. In the placebo-treated group, the chymase activity in the grafted veins was increased about 10-fold and the ACE activity was doubled. The areas of intima and media were significantly increased in the grafted veins in the placebo-treated group. L-158,809 significantly reduced the intimal area of the grafted veins. An angiotensin II receptor antagonist, L-158,809, prevented the vascular proliferation in the grafted veins, and the development of the proliferation may depend on activation of local angiotensin II formation.

Endomyocardial biopsy findings in patients with atrioventricular block in the absence of apparent heart disease

The purpose of this study was to examine the histopathological findings of right ventricular endomyocardial biopsies from ten patients less than 60 years of age (47 +/- 9.8 (mean +/- SD) years) with documented atrioventricular block but without apparent heart disease. They underwent electrophysiological testing, echocardiography, coronary angiography, and right ventricular endomyocardial biopsy. Biopsy specimens were assessed for morphologic changes in myocyte diameter, fibrosis, disarray, and degeneration. Electrophysiological testing demonstrated atrioventricular nodal block in 2, intra-His bundle block in 2, and infra-His bundle block in 6 patients. Histology revealed evidence of myocardial fibrosis with either myocyte hypertrophy or disarray in 7 of the 10 patients. The results of electrophysiological testing did not correlate with the histopathological findings or severity. In one patient, heart failure appeared during the follow-up period. We conclude that patients with atrioventricular block of unknown etiology have histological abnormalities of the ventricular endomyocardium in addition to the conduction system disturbances. We consider such cases as constituting one of the disease groups of cardiomyopathy, and suggest that it is necessary to follow up the clinical course in these patients.

Inhibition of chymase reduces vascular proliferation in dog grafted veins

We investigated the effect of a chymase inhibitor Suc-Val-Pro-Phe(P)(OPh)(2) on the proliferation of the grafted vein in dog. By 28 days after the operation, the mean intimal area of the grafted vein in the placebo group was 3.24+/-0.32 mm(2). The intimal area of the grafted vein in the chymase inhibitor-treated group was reduced to 63.9%. In the placebo group, the activities of chymase and angiotensin-converting enzyme in grafted vein were significantly increased 15- and 2-fold, respectively. In the chymase inhibitor-treated group, chymase activity in the grafted veins was decreased significantly. These findings suggest that inhibition of chymase appears useful for preventing vascular proliferation.

[Surgical treatment of septicemia after pacemaker implantation: a case report of removal of infected lead under median sternotomy]

A 73-year-old woman was admitted to our hospital because of septicemia associated with infection of an old retained pacemaker lead and a reimplanted pacemaker system. After general condition was recovered, the pacemaker system was removed and then the retained pacemaker lead was removed through median sternotomy. Then a new pacemaker system was implanted using myocardial leads. The postoperative course was uneventful.

The gene for the embryonic stem cell coactivator UTF1 carries a regulatory element which selectively interacts with a complex composed of Oct-3/4 and Sox-2

UTF1 is a transcriptional coactivator which has recently been isolated and found to be expressed mainly in pluripotent embryonic stem (ES) cells (A. Okuda, A. Fukushima, M. Nishimoto, et al., EMBO J. 17:2019-2032, 1998). To gain insight into the regulatory network of gene expression in ES cells, we have characterized the regulatory elements governing UTF1 gene expression. The results indicate that the UTF1 gene is one of the target genes of an embryonic octamer binding transcription factor, Oct-3/4. UTF1 expression is, like the FGF-4 gene, regulated by the synergistic action of Oct-3/4 and another embryonic factor, Sox-2, implying that the requirement for Sox-2 by Oct-3/4 is not limited to the FGF-4 enhancer but is rather a general mechanism of activation for Oct-3/4. Our biochemical analyses, however, also reveal one distinct difference between these two regulatory elements: unlike the FGF-4 enhancer, the UTF1 regulatory element can, by its one-base difference from the canonical octamer-binding sequence, selectively recruit the complex comprising Oct-3/4 and Sox-2 and preclude the binding of the transcriptionally inactive complex containing Oct-1 or Oct-6. Furthermore, our analyses reveal that these properties are dictated by the unique ability of the Oct-3/4 POU-homeodomain that recognizes a variant of the Octamer motif in the UTF1 regulatory element.

Carboxy-terminally truncated form of a coactivator UTF1 stimulates transcription from a variety of gene promoters through the TATA Box

We have recently isolated a novel transcriptional coactivator, UTF1, which is expressed mainly in pluripotent embryonic stem cells (Okuda, A., Fukushima, A., Nishimoto, M., Orimo, A., Yamagishi, T., Nabeshima, Y., Kuro-o, M., Nabeshima, Y., Boon, K., Keaveney, M., Stunnenberg, H. G., and Muramatsu, M. EMBO J. 17, 2019-2032, 1998). The UTF1 does not activate transcription nonspecifically, but boosts the level of transcription strictly in a specific upstream factor, ATF-2, dependent manner in mammalian cells. However, when expressed in yeast cells, the UTF1 displays a distinct activity, being able to augment the activity of minimal promoter bearing only the TATA element. Thus, these results indicate that certain domains of UTF1 render the factor inactive in terms of stimulating transcription through the basal transcription machinery in the absence of promoter-bound ATF-2 in mammalian cells. Here we report that the region bearing the leucine zipper motif is responsible for such biochemical properties of the UTF1. Indeed, UTF1 lacking functional leucine zipper is able to rather promiscuously stimulate transcription from a number of basal gene promoters such as those of hsp70 and E1B genes in mammalian cells. We have also shown that this activation is executed through TATA box by the experiments using a TBP allele with an altered TATA-binding specificity. Moreover, we have found that Dr1-mediated repression of transcription can be overcome by expression of this mutant UTF1, indicating that the observed stimulation of transcription is at least in part due to its action as an anti-repressor.

Pharmacokinetics and safety of Z-321, a novel specific orally active prolyl endopeptidase inhibitor, in healthy male volunteers

This study investigates the pharmacokinetics and safety profile of Z-321, (4R)-3-(indan-2-ylacetyl)-4-(1-pyrrolidinyl-carbonyl)-1,3-thiazoli dine, a novel specific orally active prolyl endopeptidase (PEP) inhibitor. Following a preliminary safety evaluation wherein 2 subjects received 3.75 and 15 mg doses and 2 other subjects received 7.5 and 30 mg doses, 16 subjects were assigned to two groups of 8 subjects each. In each group, 6 subjects were to receive active treatment, and 1 or 2 subjects were to receive placebo treatment. One group received 60 mg under fasted and fed conditions. A separate group of 8 subjects received 60 mg of Z-321 or a placebo in a bid regimen for 6 days and the morning dose on day 7. The concentrations of Z-321 and its main metabolites--R- and S-sulfoxide; RR-, SS-, and RS-indanol; and indanolsulfoxides in plasma and urine--were determined by the HPLC method. In the multiple-dose study, the cholinesterase activity was gradually increased and reached above the normal range on day 8 in 3 of 6 subjects given Z-321 and gradually returned to the normal range after completion of dosing. The elevation of plasma cholinesterase activity was considered to be an action of Z-321, but this remains to be verified. In a single-dose study at a dose of 30 mg, headache and vomiting were observed in 1 of 6 subjects. In the multiple-dose study, slight skin itching and eczema in 3 and 2 of 6 subjects, respectively, and headache in 2 of 6 subjects were observed, but all symptoms were not severe. There were no other abnormal findings in objective signs and laboratory findings, including blood pressure, heart rate, electrocardiogram, body temperature, hematology, blood chemistry, and urinalysis. The Cmax of Z-321 at 30, 60, and 120 mg in the fasting state were 63.7 +/- 23.9, 102.0 +/- 43.1, and 543.3 +/- 437.0 ng/ml (mean +/- SD), respectively, at 0.9 hours after administration, and the t1/2 was about 1.8 hours. There were no dramatic changes in the pharmacokinetics of Z-321 in the presence of food. In the multiple-dose study, there was no drug accumulation trend in plasma. These results indicate that Z-321 has acceptable pharmacodynamic and pharmacokinetics profiles for clinical use without any serious adverse events, as verified in healthy young male volunteers.

CYP2C19 genotype status and effect of omeprazole on intragastric pH in humans

OBJECTIVE

Omeprazole is metabolized by genetically determined S-mephenytoin 4'-hydroxylase (CYP2C19) in the liver. This study aimed to determine whether the effect of omeprazole on intragastric pH depends on CYP2C19 genotype status.

METHODS

CYP2C19 genotype status for 2 mutations associated with the poor metabolizer phenotype was determined by a polymerase chain reaction-restriction fragment length polymorphism method in 16 healthy volunteers. Helicobacterpylori status was determined by serology and the [13C]urea breath test. After a single oral administration of 20 mg omeprazole or a placebo, intragastric pH values were recorded for 24 hours. Plasma levels of omeprazole and its 2 metabolites and gastrin were measured before and 1, 2, 3, 5, 7, 10, and 24 hours after administration.

RESULTS

Fifteen of the 16 subjects were H pylori negative. Five of the 15 subjects were homozygous extensive metabolizers, 4 were heterozygous extensive metabolizers, and 6 were poor metabolizers. After omeprazole administration, significant differences in mean intragastric pH values and plasma levels of gastrin, omeprazole and its metabolites were observed among the 3 groups, whereas no significant differences in these parameters were observed with the placebo administration.

CONCLUSIONS

The effect of omeprazole on intragastric pH significantly depends on CYP2C19 genotype status. The genotyping test of CYP2C19 may be useful for an optimal prescription of omeprazole.

Effects of dothiepin on delayed conduction produced by ventricular arrhythmia in the canine heart after myocardial infarction

1. In order to clarify the arrhythmogenic effects of antidepressants, the authors examined the effects of dothiepin and amitriptyline on the ventricular activation time (VAT), effective refractory periods(ERP) and incidence of arrhythmias induced by programmed electrical stimulation(PES) in the dog heart in situ after myocardial infarction. 2. Myocardial infarction was produced by two-stage ligation of the left anterior descending coronary artery. Seven days after ligation, bipolar electrodes were sutured on the ventricular surface of the infarcted and normal zones to apply an electrical stimulation or record ventricular activation. An electrical stimulation with coupling interval 250 or 180 ms was applied on the ventricular surface, and AT was measured. 3. Dothiepin at doses of 1-3 mg/kg increased the heart rate. The VAT of coupling interval 180 ms in the infarcted zone was increased by the administration of 3 mg/kg dosulepin. Dothiepin at 3 mg/kg increased the incidence of ventricular arrhythmias induced by PES. 4. Amitriptyline, at doses of 1-3 mg/kg, significantly increased the heart rate. Amitriptyline increased the VAT dose- and frequency-dependently(2,3 mg/kg zone), and prolonged the ERP and QT c interval. Amitriptyline at doses of 1-3 mg/kg increased the incidence of ventricular arrhythmias by PES. 5. These results indicate that dothiepin, 1-3 mg/kg, has lesser effects on cardiac delayed conduction produced by ventricular arrhythmia than amitriptyline.