Biomedical subjects

M Okamoto

Publications and source records attributed to M Okamoto.

At least 271 records · Page 15Linked to original sources

PubMed1999

Conservative therapy for stage T1b, grade 3 transitional cell carcinoma of the bladder.

OBJECTIVES: To retrospectively evaluate the usefulness of transurethral resection of bladder tumor (TURBT) and intravesical instillation for pT1bG3 transitional cell carcinoma of the urinary bladder. METHODS: Between May 1984 and May 1997, 45 patients with pT1bG3 transitional cell carcinoma of the urinary bladder underwent TURBT and intravesical instillation with bacillus Calmette-Guerin (BCG) or other anticancer agents. Random biopsy was carried out in 37 patients. The recurrence-free survival rate was determined by tumor size, number of tumors, lymphovascular invasion, and drugs used for intravesical instillation. The median follow-up period was 63 months (range 4 to 145) after the initial TURBT. RESULTS: Of 37 patients who underwent random biopsy, concomitant carcinoma in situ was detected in 18 patients (48.6%). The incidence of concomitant CIS was significantly higher in patients with multiple tumors (P = 0.029). Vesical recurrence was noted in 16 patients (35.6%). The overall 1-, 3-, and 5-year recurrence-free survival rates were 88.5%, 66.7%, and 66.7%, respectively. Progression (muscular invasion) occurred in only 2 patients (4.4%). Total cystectomy was performed in 4 patients, including the 2 patients with progressive disease, and 2 patients with recurrent CIS that resisted BCG therapy. None of the patients died of bladder cancer. CONCLUSIONS: Our results suggest that aggressive attempts at initial or subsequent TURBT combined with BCG therapy achieved good control of pT1bG3 transitional cell carcinoma of the urinary bladder.

Adult↗

PubMed1999

Acridone derivatives are selective inhibitors of HIV-1 replication in chronically infected cells.

In our extensive screening of anti-HIV-1 agents in chronically infected cell lines, we have found acridone derivatives to be selective inhibitors of HIV-1 replication. Among the acridone derivatives, 1-hydroxy-10-methyl-9,10-dihydroacrid-9-one (RD6-5071) suppressed tumor necrosis factor (TNF)-alpha-induced HIV-1 expression in the latently infected cell line OM-10.1, U1, and ACH-2. Its 50% effective concentration for HIV-1 p24 antigen production was 2.0 microg/ml in OM-10.1 cells, while its 50% cytotoxic concentration was 18 microg/ml. The compound also inhibited phorbol 12-myristate 13-acetate (PMA)-induced HIV-1 expression in these cell lines. Furthermore, RD6-5071 was inhibitory to HIV-1 replication in acutely infected U937 and peripheral blood mononuclear cells. The compound was found to suppress TNF-alpha-induced HIV-1 long terminal repeat-driven gene expression. An inhibition assay for protein kinase C (PKC) revealed that RD6-5071 could reduce the enzyme activity. Furthermore, the compound was a moderate inhibitor of PMA-induced nuclear factor kappaB (NF-kappaB) activation, as determined by a gel mobility shift analysis. These results suggest that the acridone derivatives suppress HIV-1 replication at the transcriptional level primarily through a mechanism of PKC inhibition.

Acridines↗

PubMed1999

Enhancement of sensitization to nicotine-induced ambulatory stimulation by psychological stress in rats.

1. The authors investigated the influence of psychological stress (PSY-stress) on sensitization to nicotine (0.5 mg/kg, s.c.)-induced ambulatory stimulation. 2. Rats were exposed to the emotional responses of animals which received foot-shock (FS), which they, themselves, did not receive. Ten daily exposures to PSY-stress for 20 min enhanced sensitization to the nicotine-induced ambulatory stimulation compared to that in non-stress rats. 3. However, the increased serum corticosterone levels following nicotine (0.5 mg/kg, s.c.) administered 24 hr after the tenth injection of nicotine in the behavioral study was almost the same in the rats exposed to PSY-stress as compared to non-stress rats. 4. These results suggest that PSY-stress may promote sensitization to nicotine-induced ambulatory stimulation and that the combined effect of PSY-stress and nicotine would facilitate the development of sensitization to nicotine.

Animals↗

PubMed1999

Nrk: a murine X-linked NIK (Nck-interacting kinase)-related kinase gene expressed in skeletal muscle.

We report the cloning and expression pattern of a novel Ste20-type kinase gene, NIK-related kinase (Nrk), located on the mouse X chromosome. The full-length Nrk cDNA encodes a 1455-amino-acid polypeptide characterized by a N-terminal Ste20-type catalytic domain and a C-terminal regulatory domain characteristic of the group I GCK subfamily. The overall structure of the NRK protein is closely related to that of Nck-interacting kinase (Nik). In situ hybridization revealed that Nrk was predominantly expressed in skeletal muscle during mouse embryogenesis. Nrk gene expression was detected in the myotome at 10.5 dpc and, thereafter, was observed in developing skeletal musculature from 11.5 to 13.5 dpc. However, expression in skeletal muscle was not observed in adults.

Amino Acid Sequence↗

PubMed1999

Does mutation of transforming growth factor-beta type II receptor gene play an important role in colorectal polyps?

Mutations in the transforming growth factor-beta type II receptor (RII) gene that remain uncorrected due to mutation and inactivation of mismatch repair genes play an important role in hereditary nonpolyposis colorectal cancer (HNPCC) and in a subset of sporadic colorectal cancers. Some colorectal cancers develop from colorectal polyps. To elucidate the role of the RII gene in the generation of colorectal polyps, we analyzed 137 colorectal polyps from 100 patients for RII mutations and microsatellite instability (MSI). MSI was detected in three of 36 polyps from 25 patients. For one of these three polyps, the mobilities of the PCR products between polyp and nonpolyp tissues was different for only one microsatellite marker, and for the other two polyps the mobilities were different for more than two markers. These two polyps were obtained from one patient with ascending colon carcinoma and suspected HNPCC based on his clinical profile and family history. An RII mutation was detected in only one of these two polyps. RII may play a minor role in sporadic colorectal polyps. RII gene analysis in colorectal polyps may be a useful screening measure for potential HNPCC patients.

Adult↗

PubMed1999

Bone mineral density in steroid-dependent asthma assessed by peripheral quantitative computed tomography.

Chronic use of systemic glucocorticoids results in progressive bone loss and pathologic fractures. This study identified the predictive variables for bone loss and used peripheral quantitative computed tomography (pQCT) to measure changes in cortical and trabecular bone in patients receiving systemic glucocorticoid therapy of prednisone 15.4 g. Eighty-four asthmatic patients were included in the study. Vertebral fractures were diagnosed via plain spinal radiograms. pQCT was used to measure cortical and trabecular bone mineral density. Multiple regression analysis identified variables with predictive value. The cumulative dose of glucocorticoid correlated with the bone mineral density (p<0.05) and the trabecular bone density (p<0.01). Among patients > or = 65 yrs of age, the cumulative dose of glucocorticoid correlated with the occurrence of vertebral fractures (p<0.05), total bone mineral density (p<0.01) and cortical bone mineral density (p<0.01). Bone mineral density in the distal radius measured by pQCT and the vertebral bodies by axis QCT were correlated, regardless of whether systemic glucocorticoids were administered. Glucocorticoid administration not only decreases trabecular but also cortical bone mineral density. Since cortical bone provides strength and stiffness, it appears that the loss of cortical bone is responsible for the increased incidence of fracture seen in patients receiving systemic glucocorticoid therapy.

Aged↗

PubMed1999

Regulation of a putative high-affinity nitrate transporter (Nrt2;1At) in roots of Arabidopsis thaliana.

Putative high-affinity nitrate (NO3-) transporter genes, designated Nrt2;1At and Nrt2;2At, were isolated from Arabidopsis thaliana by RT-PCR using degenerate primers. The genes shared 86% and 89% identity at the amino acid and nucleotide levels, respectively, while their proteins shared 30-73% identities with other eukaryotic high-affinity NO3- transporters. Both genes were induced by NO3-, but Nrt2;1At gene expression was not apparent in 2- and 5-day-old plants. By 10 days, and thereafter, Nrt2;1At gene expression in roots was substantially higher than for the Nrt2;2At gene. Root Nrt2;1At expression levels were strongly correlated with inducible high-affinity 13NO3- influx into intact roots under several treatment conditions. The use of inhibitors of N assimilation indicated that downregulation of Nrt2;1At expression was mediated by NH4+, gln and other amino acids.

Anion Transport Proteins↗

PubMed1999

Lens formation by pigmented epithelial cell reaggregate from dorsal iris implanted into limb blastema in the adult newt.

In newt lens regeneration, the dorsal iris has lens forming ability and the ventral iris has no such capability, whereas there is no difference in the morphological criteria. To investigate the real aspects of this characteristic lens regeneration in the newt at the cellular level, a useful model system was constructed by transplanting the dorsal and ventral reaggregate derived from singly dissociated pigmented epithelial cells of the iris into the blastema of the forelimb in the newt. The lens was formed from the dorsal reaggregate with high efficiency, but not from the ventral one. No lens formation was observed in the implantation of the reaggregate into the tissue of the intact limbs. In detailed examination of the process of lens formation from the reaggregate, it was shown that tubular formation was the first step in the rearrangement of cells within the reaggregate. This was followed by depigmentation, vesicle formation with active cell growth, and the final step was lens fiber formation by transdifferentiation of epithelial cells composing the lens vesicle. The process was almost the same as in situ lens regeneration except the reconstitution of the two-layered epithelial structure was embodied as flattened tubular formation in the first step. The present study made it possible for the first time to examine lens forming ability in the reaggregate mixed with dorsal and ventral cells, because the formation of a reaggregate was started from singly dissociated cells of the dorsal and ventral cells of the iris. Mixed reaggregate experiments indicated that the existence of the dorsal cells in a cluster within the reaggregate is important in lens formation, and ventral cells showed an inhibitory effect on the formation. The present study demonstrated that the limb system thus constructed was effective for the analysis of lens formation at the cellular level and made it possible to examine the role of dorsal and ventral cells in lens regeneration.

Animals↗

PubMed1999

Endoscopic variceal ligation is a sufficient procedure for the treatment of oesophageal varices in patients with hepatitis C liver cirrhosis: comparison with injection sclerotherapy.

AIMS: Endoscopic variceal ligation (EVL) is a recently developed alternative to endoscopic injection sclerotherapy (EIS) for the treatment of oesophageal varices. Endoscopic variceal ligation and EIS were compared in an attempt to clarify the efficacy and safety of EVL for patients with cirrhosis due to hepatitis C. METHODS: Endoscopic variceal ligation was performed in 60 patients and EIS in 30. Varices were eradicated in all patients by EVL and 87% (26 out of 30) by EIS. RESULTS: There was no significant difference between EVL and EIS in relation to the incidence of bleeding and the 5 year survival rate after treatment. There were no severe complications except mild substernal pain after EVL, while pulmonary embolism occurred in one patient receiving EIS. CONCLUSIONS: Endoscopic variceal ligation is a safe and effective technique for eradicating oesophageal varices in patients with hepatitis C cirrhosis.

Esophageal and Gastric Varices↗

PubMed1999

Shift in the buoyant density of hepatitis C virus particles in infants infected by mother-to-infant transmission.

BACKGROUND: Hepatitis C virus (HCV) particles in sera can be divided into two classes: low-density free particles and high-density immune complex particles. Previous studies have revealed that the clinical progression of HCV infection is closely associated with the occurrence of the former class, rather than the latter, in an experimental chimpanzee model and in HCV-infected adult cases. METHODS: To verify this concept in infantile cases, we prospectively analysed HCV particle populations, fractionated according to buoyant density, in serum samples from five infants infected by mother-to-infant transmission. RESULTS: In all five cases, HCV particles were predominantly high density at the age of one month. In four of five cases, low-density HCV particles became predominant in association with a decrease in maternally transmitted antibody levels. In one case, in which high serum levels of alanine aminotransferase persisted, low-density particles were predominant between the ages of 3 and 9 months, in three consecutive samples. In other cases, in which infants were asymptomatic or had transient hepatitis, low-density HCV particles were predominant at only one sampling point or not at all throughout the follow-up period. CONCLUSIONS: Maternal antibody transmitted via the placenta reacts with the HCV particles in infants infected through vertical transmission. A decrease in maternal antibody levels results in an increase in low-density free virions. It is suggested that low-density particles play an important role in liver inflammation.

Centrifugation, Density Gradient↗

PubMed1999

Predicting the extent of prostate cancer using the combination of systematic biopsy and serum prostate-specific antigen in Japanese men.

OBJECTIVE: To determine the utility of systematic biopsy alone or combined with an assay of serum prostate-specific antigen (PSA) level to predict the extent of prostate cancer in Japanese men. PATIENTS AND METHODS: Thirty-two patients who were diagnosed as having clinically organ-confined prostate cancer and who underwent prostatectomy were evaluated retrospectively for the results of systematic biopsy (percentage of positive biopsy cores and cancer location), serum PSA and the pathological stage of whole-mount sections of the prostatectomy specimens. RESULTS: The incidence of extraprostatic disease (pT3N0M0 or N+) in patients with >/= 8 ng/mL of serum PSA and cancer in bilateral lobes was significantly higher than in those with <8 ng/mL PSA and cancer in one lobe (83% vs 30%, P=0.020). In those with more than half the biopsy cores positive, extraprostatic disease was significantly more common than in those with less than half positive (93% vs 44%, P=0.0075); moreover, in patients with more than half the cores positive and >/= 8 ng/mL serum PSA, it was significantly more common than in those with less than half positive and <8 ng/mL of serum PSA (93% vs 27%, P=0.0021). However, the incidence of extraprostatic disease predicted by three variables (cancer location, percentage positive biopsy cores and serum PSA) was not significantly better than that predicted by two variables (percentage positive cores and serum PSA). CONCLUSIONS: The combination of systematic biopsy and serum PSA may be useful in predicting extraprostatic cancer. Patients with >/= 8 ng/mL serum PSA and more than half the biopsy cores positive could avoid a prostatectomy because there is a high probability that they have extraprostatic disease.

Adenocarcinoma↗

PubMed1999

A case of factor VIII inhibitor-positive acquired hemophilia treated by plasmapheresis.

We report on a case of factor VIII inhibitor-positive acquired hemophilia in which combined therapy of plasma exchange (PE) and steroids was effective. The patient, a 68-year-old man, had undergone hemodialysis since April 1998, due to chronic renal failure caused by diabetic nephropathy. The hemostasis of blood access sites gradually became difficult after the initiation of dialysis and the prolongation of activated partial thromboplastin time (APTT) (74.5 s), and a decrease in factor VIII (0.02%) and an abnormally high concentration of factor VIII inhibitor (111 U/ml) were found. Under the diagnosis of factor VIII inhibitor-positive acquired hemophilia, 3 consecutive PE were performed, followed by a large dose administration of gamma globulin. However, the effect of this therapy disappeared within 20 days. Then the PE therapy was performed again accompanied by pulse methylprednisolone therapy. After that, factor VIII inhibitor was suppressed and the patient's hemostatic defect continued to improve even after the reduction of the steroid dose. These results suggest that PE is very effective in treating factor VIII inhibitor-positive acquired hemophilia.

Aged↗

PubMed1999

Long-term follow-up results of a Pilot Phase II study of multidrug chemotherapy (MVP-CAB) in patients with advanced urothelial cancer.

BACKGROUND: To determine the long-term effects and toxicity of multidrug chemotherapy for advanced urothelial cancer. METHODS: Forty patients with metastatic urothelial cancer were treated with a new combination chemotherapy, MVP-CAB (methotrexate, doxorubicin, vincristine, cyclophosphamide, bleomycin and cisplatin every 28 days). Of the 40 patients, 26 had not undergone prior chemotherapy or radiotherapy; the remaining 14 patients had undergone prior cisplatin-based chemotherapy. RESULTS: The clinical response rate to MVP-CAB therapy for all 40 patients was 63% [complete response (CR), six patients; partial response (PR), 19 patients]. The median duration of the effects was 22 and 13 months in the patients with CR and PR, respectively. The clinical response rate for the 26 patients without prior chemotherapy was 77% (CR, four patients; PR, 16 patients). The rate for the 14 patients with prior chemotherapy was 36% (CR, two patients; PR, three patients). The response rate according to metastatic site was highest for the liver (80%), followed by the lymph nodes (74%) and lungs (67%). The effect on bone metastasis was poor (22%). There was good compliance with the MVP-CAB chemotherapy regimen and toxicity was tolerable. The 1-, 3- and 5-year overall survival rates were 42.5, 10 and 5%, respectively. CONCLUSIONS: MVP-CAB combination chemotherapy was found to be effective for the treatment of advanced urothelial cancer, especially for liver metastasis.

Adult↗

PubMed1999

Enhanced resistance to bacterial diseases of transgenic tobacco plants overexpressing sarcotoxin IA, a bactericidal peptide of insect.

Sarcotoxin IA is a bactericidal peptide of 39 amino acids found in the common flesh fly, Sarcophaga peregrina. Many agronomically important bacteria in Japan are killed by this peptide at sub-micro molar levels, and the growth of tobacco and rice suspension cultured cells is not inhibited with less than 25 microM. Transgenic tobacco plants which overexpress the peptide, i.e. over 250 pmol per gram of fresh leaf, under the control of a high expression constitutive promoter showed enhanced resistance to the pathogens for wild fire disease (Pseudomonas syringae pv. tabaci) and bacterial soft rot disease (Erwinia carotovora subsp. carotovora).

Animals↗

PubMed1999

Hodgkin's disease expressing follicular dendritic cell marker CD21 without any other B-cell marker: a clinicopathologic study of nine cases.

Reed-Sternberg (RS) and Hodgkin's (H) cells are considered to be the neoplastic cells in Hodgkin's disease (HD). Although most data suggest their lymphoid origin, the nature of these cells still remains a subject of controversy. Recently, a number of RS cells have been found to express an antigen that is also present on follicular dendritic cells (FDCs), asserting FDCs as the possible progenitor cells of H-RS cells. This prompted us to investigate whether these CD21-positive cases had distinct clinicopathologic characteristics. In a series of 94 examined cases of HD, we identified 9 CD21-positive ones (4 of 37 cases of nodular sclerosis, 1 of 41 mixed cellularity, and 4 of 12 lymphocyte depletion HD) without any other B-cell marker on paraffin sections. The patients varied in age from 16 to 82 years (median, 50 years) and included six men and three women. They had superficial or mesenteric lymphadenopathy without hepatosplenomegaly. Peripheral blood leukocytosis was seen in three patients. The clinical course was indolent, and all patients but one achieved an initial complete response with HD-based treatment regimens, although three of them relapsed. Morphologically, two subgroups could be delineated. Six of the cases were characterized, besides by the classic RS cells, by a varying number of the cells with the distinctive walnutlike or cerebrumlike nuclei and cytologically with cytoplasmic processes. Their fine structural examination also revealed villous processes, but no desmosomes. The other three cases had multinucleated RS cells often with triangular nuclei, but not cytoplasmic processes. The percentage of CD21-positive tumor cells ranged from less than 10% to 60% among the H-RS cells. These RS cells were positive for CD30 (9 of 9), CD15 (7 of 9), CD68 (1 of 8), fascin (8 of 8), S-100 protein (1 of 7), and epithelial membrane antigen (2 of 8) on paraffin sections. Notably, of eight cases examined on frozen sections, two showed immunostaining for DRC1, CD35, R4/23, and Ki-M4p. Only CD35 was also detected in the other two cases. Genotypic investigation showed germline configuration of the T-cell receptor beta and gamma chain genes and the immunoglobulin heavy chain gene in all eight cases examined. In situ hybridization showed Epstein-Barr virus sequences in four cases, three of which were examined by the terminal region analysis and showed the Epstein-Barr virus to be monoclonal. We concluded that in a small proportion (9.6%) of HD, H-RS cells might be derived from FDCs and that they appear to represent a distinct pathologic variant based on morphologic and phenotypic traits within the framework of HD.

Adolescent↗

PubMed1999

Nodal cytotoxic lymphoma spectrum: a clinicopathologic study of 66 patients.

The expression of cytotoxic granule-associated proteins has been reported in some T-cell or natural killer (NK)-cell lymphomas of mostly extranodal origin, but rarely of nodal origin except for anaplastic large cell lymphoma (ALCL) and Hodgkin's disease (HD). This study analyzed 66 nodal lymphomas expressing T-cell intracellular antigen-1 (TIA-1) and/or granzyme B to characterize the clinicopathologic spectrum of these neoplasms. Four main groups could be delineated. The first group consisted of p80/anaplastic lymphoma kinase (ALK)-positive ALCL (n = 35). The patients were 2 to 62 years of age (median age, 16 years), and the lymphomas pursued a relatively indolent clinical course. The tumors were phenotypically of either T- or null-cell type with constant expression of CD30, epithelial membrane antigen (EMA), and p80/ALK, but not CD15 or BCL2. None harbored Epstein-Barr virus (EBV). The second group consisted of peripheral T/NK-cell lymphoma, the nodal high-grade cytotoxic type (n = 13). The patients were 29 to 72 years in age (median age, 55 years), and the tumors pursued an aggressive clinical course. The tumors often showed pleomorphic, anaplastic, or centroblastoid morphology, and were featured by either EBV association or CD56 expression. The third group consisted of peripheral T-cell lymphoma, of the nodal low-grade cytotoxic type (n = 8). The patients, three men and five women, were 31 to 75 years old (median age, 61 years). Notably, six of them exhibited lymphoepithelioid (Lennert's) lymphoma. The fourth group consisted of cytotoxic Hodgkin's-like ALCL/HD (n = 10), included seven cases of Hodgkin's-like ALCL and three cases of HD, and was characterized by the presence of Reed-Sternberg cells and often the CD15+ phenotype. The patients were all men except for one woman, and they ranged in age from 24 to 84 years (median age, 62 years). The link among these four groups was reinforced by the presence of a highly characteristic large cell with horseshoelike or reniform nuclei-the frequent expression of CD30 and EMA-and the often lack of T-cell receptor-alphabeta. In this series, the expression of p80/ALK and CD56 was also associated with favorable and poor prognoses respectively (p<0.001, log-rank test).

Adolescent↗

PubMed1999

Pharmacodynamics and the plasma concentration of mivacurium during spontaneous recovery and neostigmine-facilitated recovery.

BACKGROUND: The authors examined the plasma concentrations of the isomers of mivacurium and its pharmacodynamics during spontaeous and neostigmine-facilitated recovery after a mivacurium infusion. METHODS: Sixteen patients receiving nitrous oxide-opioid anesthesia received 0.25 mg/kg mivacurium. Patient response to neuromuscular stimulation was determined using a mechanomyograph Once T1 had recovered to 25% of its baseline height, a mivacurium infusion was begun and adjusted to maintain 95-99% neuromuscular block. The infusion was discontinued after 90 min and muscle strength allowed to recover either spontaneously or after neostigmine/glycopyrrolate (0.05/0.01 mg/kg). Plasma concentrations of the isomers of mivacurium after discontinuation of the infusion were determined using an HPLC assay. Differences between the groups were determined using a one-way analysis of variance with a Bonferroni-corrected t test or Student t test as appropriate. P < or = 0.05 was considered significant. RESULTS: Differences in the times for recovery to a train-of-four ratio of 70% did not achieve statistical significance (mean+/-SD, 13.3+/-6.0 vs. 16.3+/-2.5 min for the neostigmine and spontaneous groups, respectively). Plasma cholinesterase activity decreased significantly from baseline values after administration of neostigmine (5.88+/-0.21 vs. 0.43+/-0.04 U/ml plasma). Plasma concentrations of the trans-trans isomer were significantly greater in the neostigmine group than in the spontaneous recovery group 5, 6, 8, and 10 min after discontinuation of the infusion. Differences in the plasma concentration of the cis-trans isomer did not achieve statistical significance. CONCLUSIONS: Although administration of neostigmine decreased plasma cholinesterase activity and caused the trans-trans isomer to remain in the plasma at higher concentration, it did not delay recovery from mivacurium-induced block.

Adult↗

PubMed1999

Localization of precise origin of idiopathic ventricular tachycardia from the right ventricular outflow tract by a 12-lead ECG: a study of pace mapping using a multielectrode "basket" catheter.

Radiofrequency catheter ablation guided by pace-mapping techniques has proven effective in eliminating idiopathic ventricular tachycardia (VT) originating from the right ventricular outflow tract (RVOT). A method for rapidly identifying the origin of VT from 12-lead electrocardiogram (ECG) findings would be helpful for the catheter ablation procedure. The purpose of this study is to precisely localize the origin of idiopathic VT from the RVOT by a 12-lead ECG from a study of multipoint pace mapping. In one patient with premature ventricular complex (PVC) and 3 with VT, a "basket" catheter was deployed in the RVOT for bipolar pacing from 56 sites in the endocardium of RVOT. Under fluoroscopy the pacing sites were classified into the septum and free wall. We investigated the QRS morphology in leads, I, II, and III; the depth of the QS wave in leads aVR and aVL; and the height of the initial r wave in leads V1 and V2. Pacing was captured in 30-47 of 56 sites (54%-84%). As the pacing sites changed from the anterior to posterior of the septum, the QS notch (-) type in lead I shifted through rs to R, while a shift from R type to rR' or Rr' was noted in leads II and III. As the pacing sites changed from the anterior to posterior of the free wall, lead I showed a shift from the QS notch (+) type to R, while a shift from rR' to Rr' (or rR' unchanged) was found in leads II and III. The depth of the QS wave in leads aVR and aVL showed a tendency for aVR to be deeper than aVL toward the posterolateral attachment of both the septum and free wall, whereas aVL tended to be deeper than aVR toward the anterior attachment. The initial r waves in V1 and V2 became greater as the pacing site was positioned at a higher or more posterior location. These findings may provide more precise and clinically useful diagnostic information on the site of the origin of idiopathic VT originating from the RVOT by a 12-lead ECG.

Adult↗