Predictive factors of recurrent atrial tachyarrhythmia after multiple procedures of radiofrequency catheter ablation for paroxysmal atrial fibrillation: Kansai Plus Atrial Fibrillation Registry (KPAF)

Background

The predictors of arrhythmia recurrence after radiofrequency catheter ablation (RFCA) for paroxysmal atrial fibrillation (PAF) have not yet been fully evaluated.

Purpose

The aim of this study was to develop and validate a risk scoring system to predict the incidence of recurrence of atrial tachyarrhythmia after the final RFCA for PAF.

Methods

The study population consisted of 3223 consecutive patients undergoing first-time RFCA for PAF from November 2011 to March 2014 in 26 cardiovascular centers in Japan who were enrolled in the Kansai Plus Atrial Fibrillation (KPAF) registry. We developed a scoring system in a derivation cohort with 2149 patients and assessed its reproducibility in a validation cohort with 1074 patients. The primary endpoint was recurrent atrial tachyarrhythmia lasting for ≥30 seconds after 91 days post the final ablation.

Results

During a median follow-up period of 3.1 years, 404 (18.8%) patients of the derivation cohort had AF recurrence after the final RFCA. The baseline patient characteristics of the derivation cohort were as follows: mean age 64.7 years, male 1480 (68.9%), mean body mass index (BMI) 23.6 kg/m2, hypertension 1122 (52.2%), prior heart failure 182 (8.5%), diabetes mellitus 203 (9.5%), prior stroke and/or transient ischemic attack 21 (1.0%), prior vascular disease 209 (9.7%), prior valvular disease 105 (4.9%), median CHADS2 score 1.1, median CHA2DS2-VASc score 2.1, mean number of ineffective antiarrhythmic drugs (AAD) 0.80, median duration of history of AF episodes 2.1 years, mean left atrial diameter (LAD) 38.2 mm, mean left ventricular ejection fraction (LVEF) 65.3%, and mean eGFR 68.7 mL/min/1.73m2. There was no significant difference in the baseline characteristics between derivation and validation cohorts. The results of the multivariate logistic regression models identified 5 independent variables of recurrent atrial tachyarrhythmia after the final RFCA: female (odds ratio (OR) = 1.45, p=0.0017), BMI <25 kg/m2 (OR=1.40, p=0.0081), duration of AF history 3 years≤ (OR=1.39, p<0.0034), chronic kidney disease (CKD) (OR=2.1, p=0.005, for stage 2/3CKD, OR=2.6, p=0.018 for stage 4/5 CKD), and LVEF (OR=2.1, p=0.039 for LVEF <50%, OR=1.5, p=0.022 for LVEF 50–60%). The predictive score for each factor was 3 points for CKD stage 4/5, 2 for CKD stage2/3 and LVEF <50%, and 1for the others (11 points in total). The arrhythmia-free rates after the final RCFA in the derivation cohort according to the score were as follows: 0–2 points = 91.7%, 3–4 = 80.7%, 5< = 72.6%, respectively. The similar results were reproduced in the validation cohort (Figure 1).

Conclusion

Our newly developed scoring system, composed of female, BMI, AF duration, CKD, and LVEF, could reproducibly predict arrhythmia recurrence after the final RFCA for PAF.

Funding Acknowledgement

Type of funding source: None

Sex differences in the predictors of recurrent atrial fibrillation after catheter ablation: insights from the Kansai Plus Atrial Fibrillation (KPAF) registry

Background

The impact of sex differences on the clinical outcomes of radiofrequency catheter ablation (RFCA) of atrial fibrillation (AF) is controversial. We previously reported that females experienced more frequent AF recurrences than males after the index and last RFCA procedures.

Purpose

To identify the risk factors associated with recurrent AF in females and males after RFCA of AF.

Methods

We conducted a large-scale, prospective, multicenter, observational study (Kansai Plus Atrial Fibrillation Registry). We enrolled 5010 consecutive patients who underwent an initial RFCA of AF at 26 centers (64±10 years; 1369 [27.3%] females; non-paroxysmal AF, 35.7%). The median follow-up duration was 2.9 years.

Results

The incidence of AF recurrences after a single procedure was 43.3% in females and 39.0% in males. After a multivariate adjustment at baseline, the significant predictors of AF recurrence in females after the index RFCA were non-paroxysmal AF (hazard ration [HR],1.59; 95% confidence interval [CI],1.31–1.93, p<0.0001), a history of AF ≥2 years (HR,1.47; 95% CI,1.24–1.74, p<0.0001), coronary artery disease (HR,1.43; 95% CI,1.03–1.98, p=0.0035), and an estimated glomerular filtration rate (eGFR)<60 mL/min/1.73m2 (HR,1.46; 95% CI,1.10–1.95, p=0.0086). On the other hand, significant predictors of AF recurrence in males after the index RFCA were non-paroxysmal AF (HR,1.54; 95% CI,1.37–1.73, p<0.0001), a history of AF ≥2 years (HR,1.40; 95% CI,1.26–1.56, p<0.0001), the number of antiarrhythmic drugs (HR,1.06; 95% CI,1.003–1.13, p=0.040), a left atrial diameter≥40mm (HR,1.13; 95% CI,1.007–1.27, p=0.038), and dilated cardiomyopathy (HR,1.55; 95% CI,1.07–2.26, p=0.021), however, an eGFR<60 mL/min/1.73m2 was not associated with AF recurrence in males (HR, 1.00; 95% CI, 0.88–1.13, p=0.97).

Conclusion

The Kansai Plus Atrial Fibrillation Registry revealed a distinct sex difference in terms of the predictors of recurrent AF after RFCA. Non-Paroxysmal AF and a long history of AF were common risk factors both in females and males. However, renal dysfunction was a significant predictor of AF recurrence in females, while it was not a risk of recurrence in males.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): Research Institute for Production Development in Kyoto, Japan.

P5652Catheter ablation outcome and heart failure hospitalization in atrial fibrillation patients with preserved left ventricular ejection fraction: insights from the Kansai plus atrial fibrillation (KPAF)

Background

Heart failure (HF) is the leading cause of death in patients with atrial fibrillation (AF), and AF is an independent prognostic factor in HF patients with preserved left ventricular ejection fraction (LVEF). Radiofrequency catheter ablation (RFCA) for AF is effective to maintain sinus rhythm.

Purpose

We sought to clarify incidence of HF hospitalization and whether AF ablation outcome influenced incidence of HF hospitalization after the procedures in patients with preserved LVEF.

Methods

We conducted a large-scale, prospective, multicenter, observational study. A total of 4522 consecutive patients with normal LVEF (>/- 50%) who underwent an initial RFCA for AF in 26 centers were enrolled (average age, 64±10 years; non-paroxysmal AF, 33.7%). The median follow-up duration was 2.9 years.

Results

The 3-year cumulative incidence of AF recurrence after a single procedure was 40.3%. Hospitalization for HF was observed in 60 patients (1.3%) and was significantly higher in patients with AF recurrence than those without it (2.63% vs 0.44%, log-rank p<0.001). After adjustment by age ≥65 years, estimated glomerular filtration rate ≤60ml/min, history of HF, and female, all of which were statistically associated with a risk of HF hospitalization, AF recurrence after the index RFCA was an independent predictor of HF hospitalization (hazard ratio; 4.75, 95% confidence interval; 2.59–9.42, p<0.001).

Conclusions

Recurrence after RFCA for AF was a significant risk of HF hospitalization among AF patients with preserved LVEF.

Acknowledgement/Funding

This study was supported by the Research Institute for Production Development in Kyoto, Japan.

P1029Catheter ablation outcome and heart failure hospitalization in atrial fibrillation patients: insights from the Kansai plus atrial fibrillation (KPAF) registry

Background

Heart failure (HF) is the leading cause of death in patients with atrial fibrillation (AF). Radiofrequency catheter ablation (RFCA) for AF is effective to maintain sinus rhythm.

Purpose

We sought to clarify whether AF ablation outcome influenced incidence of HF hospitalization after the procedures.

Methods

We conducted a large-scale, prospective, multicenter, observational study. A total of 5010 consecutive patients who underwent an initial RFCA for AF in 26 centers were enrolled (average age, 64±10 years; non-paroxysmal AF, 35.6%). The median follow-up duration was 2.9 years.

Results

The 3-year cumulative incidence of AF recurrence after a single procedure was 40.2%. The 3-year incidence of hospitalization for HF was observed in 92 patients (1.8%) and was significantly higher in patients with AF recurrence than those without it (3.3% vs 0.84%, log-rank p<0.001). After adjustment by advanced age,(≥65 years), reduced left ventricular ejection fraction (≤50%), low estimated glomerular filtration rate (≤60ml/min), and history of HF, all of which were statistically associated with a risk of HF hospitalization (p<0.1, respectively), AF recurrence after the index RFCA was an independent predictor of HF hospitalization (hazard ratio [HR]; 3.17, 95% confidence interval [CI]; 2.06–5.04, p<0.001).Even after multiple procedures (1425 re-ablation sessions in 1274 patients [25.4%]), AF recurrence after the last procedure was an independent predictor of HF hospitalization (HR; 2.83, 95% CI; 1.89–4.24, p<0.001).

Conclusions

Among AF patients receiving RFCA, those with AF recurrence were at greater risk of heart failure hospitalization than were patients without AF recurrence. These differences should be noted when treating AF patients in actual clinical practice.

Acknowledgement/Funding

This study was supported by the Research Institute for Production Development in Kyoto, Japan.

P5650Improvement in ejection fraction predicts heart failure after catheter ablation for atrial fibrillation in patients with left ventricular systolic dysfunction: from the KPAF registry

Introduction

The presence of atrial fibrillation (AF) in patients with reduced left ventricular ejection fraction (LVEF) is associated with increased risks of mortality and hospitalization for heart failure (HF). Although prior studies reported that catheter ablation (CA) for AF in low LVEF patients reduced risks of all-cause mortality and HF hospitalization, the predictors of worsening HF after ablation has not been adequately evaluated.

Purpose

The purpose of this study was to investigate the impact of improvement in LVEF after AF ablation on the incidence of subsequent HF hospitalization in patients with low LVEF.

Methods

The Kansai Plus Atrial Fibrillation (KPAF) Registry is a multicenter registry enrolling 5,013 consecutive patients undergoing first-time ablation for AF. The current study population consisted of 1,031 patients with reduced LVEF of <60%. We divided the study population into 3 groups according to LVEF at follow-up; 678 patients (65.8%) with improved LVEF (≥5 U change in LVEF), 288 patients (27.9%) with unchanged LVEF (−5 U ≤ change in LVEF <5 U) and 65 patients (6.3%) with worsened LVEF (<−5 U change in LVEF).

Results

During the median follow-up of 1067 [879–1226] days, patients improved LVEF had lower rate of HF hospitalization, compared with those with unchanged and worsened LVEF (2.1%, 8.0%, and 21.5%, respectively, P<0.0001). Recurrent atrial tachyarrhythmias were documented in 43.5%, 47.2% and 67.7%, respectively (P=0.0008).

Figure 1

Conclusion

Among patients with reduced LVEF undergoing AF ablation, patients with subsequently improved LVEF in association with maintained sinus rhythm had markedly lower risk of HF hospitalization during follow-up as compared with those with unchanged or worsened LVEF.

Botanical origin and chemical constituents of commercial Saposhnikoviae radix and its related crude drugs available in Shaanxi and the surrounding regions

Saposhnikoviae radix (SR) is described in the Japanese Pharmacopoeia as a crude drug derived from the root of Saposhnikovia divaricata Schischkin (Umbelliferae). According to Flora of China, the root of Peucedanum ledebourielloides K. F. Fu is used as a regional substitute for SR. Therefore, we surveyed the botanical origin of the drug used in China, especially Shaanxi and the surrounding regions, through nucleotide sequence analysis of the internal transcribed spacer region of rDNA. As a result, several samples from Shaanxi () and Shanxi () provinces were identified as Peucedanum ledebourielloides. To prevent this substitute from being distributed as genuine SR, we developed a thin-layer chromatography analysis condition to enable a specific compound of this species to be easily detected. The specific compound was identified as xanthalin, based on 1D- and 2D-NMR and high-resolution mass spectrometry data. The established TLC conditions were as follows-extraction solvent, n-hexane; applied volume, 5 µL; chromatographic support, silica gel; developing solvent, n-hexane:ethyl acetate:acetic acid (20:10:1); developing length, 7 cm; detection, UV (365 nm); R _f value, 0.4 (blue fluorescence; xanthalin).

Species identification of licorice using nrDNA and cpDNA genetic markers

For the accurate identification of medicinal licorice species, nucleotide sequences of four types of DNA regions were researched for 205 specimens, including three species used as licorice: Glycyrrhiza uralensis, Glycyrrhiza glabra, and Glycyrrhiza inflata. The four DNA regions were the internal transcribed spacer (ITS) on nuclear ribosomal DNA, the rbcL gene, the matK gene, and the trnH-psbA intergenic region on chloroplast DNA (cpDNA). Ten genotypes were consequently recognized as combinations of the sequence data obtained from the four DNA regions. Species-specific genotypes were defined from the frequency of the appearance of species in each genotype and from the phylogenetic relationships of the 10 genotypes. This revealed the possibility of identifying licorice species based on the 10 genotypes. Next, comparison of species identifications by each DNA region suggested that efficient identification of licorice species is possible using the genetic information obtained from the ITS and trnH-psbA intergenic region. Additionally, concerning the phylogenetic relationships of the Glycyrrhiza species used as licorice, it is suggested from the genetic information of the four types of DNA regions that G. glabra is more closely related to G. inflata than to G. uralensis. In the G. uralensis examined, four genotypes were recognized as intra specific variations. The appearance frequency of each genotype in G. uralensis differed according to the area in China. G. uralensis may have expanded its distribution areas from western to eastern China because many licorices with the phylogenetic ancestral genotype were observed in western areas, while many with the derivative genotype were observed in eastern areas.

Reticulate evolution and phylogeography in Asarum sect. Asiasarum (Aristolochiaceae) documented in internal transcribed spacer sequences (ITS) of nuclear ribosomal DNA

Phylogenetic analyses were performed for the taxonomically complicated group, Asarum sect. Asiasarum, using internal transcribed spacers (ITS) of nuclear ribosomal DNA. Direct sequences for 99 samples of a total of 14 taxa and geographic races and cloning analyses for 32 of these samples provided new insights that extensive reticulate evolution has occurred in this group. Eight taxa had slight or no polymorphism of the ITS sequences. On the other hand, the other five taxa had polymorphic ITS sequences composed of two ribotypes that were completely the same or almost the same as the sequences recognized in the taxa with only slight or no polymorphism, and were probably of diploid hybrid origin and to have retained their parental ribotypes. In terms of biogeographic implications, at least four interactions including migration, hybridization, and introgression, were presumed between the Japanese Archipelago and the continents, two times via a southern route, from the Korean Peninsula, and two times via a northern route, from Sakhalin or directly from the Eurasian continent.

Identification of medicinal Atractylodes based on ITS sequences of nrDNA

Dried rhizomes of five species of Atractylodes (A. japonica, A. macrocephala, A. lancea, A. chinensis, and A. koreana), Compositae, have been used as crude drugs mainly for the treatment of stomach disorders and for their diuretic properties in Chinese and Japanese traditional medicines. The identification of the botanical origins of these crude drugs is generally difficult from their morphological and chemical features only. In this study, for identification with more reliable, nuclear ribosomal DNA (nrDNA), internal transcribed spacer (ITS) regions of five species of medicinal Atractylodes were sequenced. As a result, specific ITS genotypes were recognized by each species. The four species (A. japonica, A. macrocephala, A. lancea, and A. chinensis) prescribed in Chinese and Japanese Pharmacopoeias as botanical origins of crude Atractylodes drugs could be distinguished by their ITS sequences because they had difference genotypes on the ITS sequences. However, the genotype of A. koreana was the same as that of A. chinensis. Additionally, hybrids between A. lancea and A. chinensis were also recognized as nucleotide additives on their ITS sequences. In this study, several morphological characteristics were researched by their genotype, too. As this result, the hybrids recognized from the genetic analysis had intermediate morphological characteristics between A. lancea and A. chinensis. It was also recognized that A. lancea and A. chinensis except for their hybrids were significant differences. It is therefore suggested that ITS sequences of nrDNA would be useful for the identification of the crude drugs derived from Atractylodes species and their interspecific hybridizations.

Use of nonionic surfactants for effective supply of phosphatidic acid in serum-free culture of Chinese hamster ovary cells

We have previously shown [Sakai et al., J. Biosci. Bioeng., 88, 306-309 (1999)] that exogenously supplied phosphatidic acid (PA) and lysophosphatidic acid (LPA) promoted the growth of Chinese hamster ovary (CHO) cells in serum-free culture. However, the direct addition of high concentrations of these phospholipids alone to the culture medium resulted in the formation of precipitates. We therefore examined the use of two nonionic surfactants, Tween 80 and Pluronic F-68, as a means of supplying PA more effectively to CHO cells in a serum-free culture. A clear dispersion of PA from egg yolk lecithin that could be successfully sterile-filtered was obtained by using Tween 80 or Pluronic F-68. When PA prepared with either of the surfactants was added to serum-free media, precipitation was noticeably reduced. Furthermore, the growth-promoting activity of PA was considerably enhanced by the presence of the surfactants. Since Tween 80 and Pluronic F-68 themselves possessed no growth-stimulating property, it was suggested that the enhanced growth-promoting activity results from the improved availability of PA to the cells. The use of Tween 80 with PA analogues having saturated acyl chains also accelerated cell growth, whereas these PAs showed little growth-promoting activity, due to their poor water-solubility, when added alone.

Production of recombinant protein by baculovirus-infected insect cells in immobilized culture using porous biomass support particles

Immobilization of insect cells using porous biomass support particles (BSPs) and production of a recombinant protein by the immobilized cells after infection with a baculovirus were investigated in a shake-flask culture. Sf9 cells were passively immobilized in reticulated polyvinyl formal (PVF) resin BSPs (2 x 2 x 2 mm cubes) with matrices of 60 mum mean pore diameter in situ in shake-flasks. The cell density in the BSPs was over 5 x 10(7) cells/cm3-BSP in cultures with regular replacement of the culture medium, as estimated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. After infection with a recombinant baculovirus carrying the beta-galactosidase gene, immobilized cells within the BSPs showed a high specific productivity, comparable to the maximum productivity in shake-flask cultures of non-immobilized cells, as long as nutrients in the medium were not depleted. Even when immobilized cells at a high density of 5 x 10(7) cells/cm3-BSP were infected with the baculovirus, efficient beta-galactosidase production with a high specific productivity was possible by replacing the medium at appropriate intervals to avoid nutrient depletion.

Effects of phospholipids on growth of Chinese hamster ovary cells in serum-free media

The effects of phosphatidic acid (PA) and lysophosphatidic acid (LPA) dispersed in serum-free media on the growth of Chinese hamster ovary (CHO) cells were investigated. After cells were incubated in serum-free media supplemented with PA or LPA for 3 d, the cellular growth was evaluated by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. Supplementing PA from egg yolk lecithin to basal synthetic media such as alpha-MEM (minimum essential medium, alpha modification) markedly promoted the growth of CHO cells. PA from egg yolk lecithin also enhanced the cell growth in a serum-free medium containing insulin and transferring. When PA analogues with different acyl chains of C14-18 were compared, PA with unsaturated acyl chains, dioleoyl-PA (C18: 1), was most effective for stimulating the growth of CHO cells. Similar results were obtained when LPA was examined. These results suggest that PA and LPA, especially those with unsaturated acyl chains, are promising growth-promoting supplements for use as constituents in a low-protein serum-free medium.

Optimal production of recombinant protein by the baculovirus-insect cell system in shake-flask culture with medium replacement

Sf9 insect cells infected with a recombinant baculovirus expressing beta-galactosidase and suspended in fresh medium (TNM-FH supplemented with 10% fetal bovine serum) at the time of infection were cultured in shake flasks at various combinations of initial cell density and multiplicity of infection (MOI). The effects of cell density and MOI on beta-galactosidase production were quantitatively analyzed by plotting the beta-galactosidase yield against the time integral of the viable cell density from the time of infection to the time when the beta-galactosidase production reached a plateau. The beta-galactosidase yield had a maximum value at a viable cell density time integral of approximately 8 x 10(6) cells.d/cm3 for each MOI used in a range from 0.01 to 10 plaque-forming units per cell (pfu/cell). Since glucose and fructose were exhausted when the culture reached 8 x 10(6) cells.d/cm3, it was concluded that protein production in a high-cell-density culture was limited by nutrient depletion in the culture medium, and hence the nutritional capacity of the medium was able to be determined as the viable cell density time integral at which the maximum product yield was attained. In cultures infected at a low MOI (< or =1 pfu/cell), the specific productivity, and thereby the yield, of beta-galactosidase declined with decreasing MOI due to the reduction in the proportion of initially infected cells. These results indicate that production of a recombinant protein in a culture with medium replacement at the time of infection can be optimized if the cells are infected at a high MOI (> or = 1 pfu/cell) and at a cell density such that the viable cell density time integral reaches the nutritional capacity just as the protein production is completed.

Preimplantation B-type natriuretic peptide concentration is an independent predictor of future appropriate implantable defibrillator therapies

OBJECTIVE

To assess prospectively whether preimplantation B-type natriuretic peptide (BNP) and C reactive protein (CRP) concentrations predict future appropriate therapies from an implantable cardioverter-defibrillator (ICD).

DESIGN AND SETTING

Prospective cohort study conducted in a tertiary cardiac care centre.

METHODS

345 consecutive patients undergoing first time ICD implantation were prospectively studied. Serum BNP and CRP concentrations were obtained the day before ICD implantation. Patients were followed up with device interrogation to assess for appropriate shocks or antitachycardia pacing. Inappropriate therapies were excluded. Mean (SD) follow up was 13 (5) months.

RESULTS

Patients had ischaemic (71%), primary dilated (17%), and valvar or other cardiomyopathies (12%). About half (52%) had ICDs implanted for primary prevention. Sixty three (18%) received appropriate ICD therapies. Serum creatinine, beta blocker, statin, and angiotensin converting enzyme inhibitor usage did not differ between therapy and no therapy groups. By univariate comparison, ejection fraction (p = 0.048), not taking amiodarone (p = 0.033), and BNP concentration (p = 0.0003) were risk factors for ICD therapy. However, by Cox regression multivariate analysis, only BNP above the 50th centile was a significant predictor (hazard ratio 2.19, 95% confidence interval 1.07 to 4.71, p = 0.040). Median BNP was 573 ng/l versus 243 ng/l in therapy and no therapy patients, respectively (p = 0.0003). More patients with BNP above the 50th centile (27% v 10%, p = 0.006) received ICD therapies.

CONCLUSIONS

A single preimplantation BNP concentration determination is independently predictive of ICD therapies in patients with cardiomyopathies undergoing first time ICD implantation. CRP was not independently predictive of ICD therapies when compared with BNP.

Prediction of acute left main coronary artery obstruction by 12-lead electrocardiography. ST segment elevation in lead aVR with less ST segment elevation in lead V(1)

OBJECTIVES

We sought to determine the electrocardiographic (ECG) features associated with acute left main coronary artery (LMCA) obstruction.

BACKGROUND

Prediction of LMCA obstruction is important with regard to selecting the appropriate treatment strategy, because acute LMCA obstruction usually causes severe hemodynamic deterioration, resulting in a less favorable prognosis.

METHODS

We studied the admission 12-lead ECGs in 16 consecutive patients with acute LMCA obstruction (LMCA group), 46 patients with acute left anterior descending coronary artery (LAD) obstruction (LAD group) and 24 patients with acute right coronary artery (RCA) obstruction (RCA group).

RESULTS

Lead aVR ST segment elevation (>0.05 mV) occurred with a significantly higher incidence in the LMCA group (88% [14/16]) than in the LAD (43% [20/46]) or RCA (8% [2/24]) groups. Lead aVR ST segment elevation was significantly higher in the LMCA group (0.16 +/- 0.13 mV) than in the LAD group (0.04 +/- 0.10 mV). Lead V(1) ST segment elevation was lower in the LMCA group (0.00 +/- 0.21 mV) than in the LAD group (0.14 +/- 0.11 mV). The finding of lead aVR ST segment elevation greater than or equal to lead V(1) ST segment elevation distinguished the LMCA group from the LAD group, with 81% sensitivity, 80% specificity and 81% accuracy. A ST segment shift in lead aVR and the inferior leads distinguished the LMCA group from the RCA group. In acute LMCA obstruction, death occurred more frequently in patients with higher ST segment elevation in lead aVR than in those with less severe elevation.

CONCLUSIONS

Lead aVR ST segment elevation with less ST segment elevation in lead V(1) is an important predictor of acute LMCA obstruction. In acute LMCA obstruction, lead aVR ST segment elevation also contributes to predicting a patient's clinical outcome.

Transesophageal echocardiography for detection of mitral regurgitation due to papillary muscle rupture or dysfunction associated with acute myocardial infarction: a report of five cases

Severe mitral regurgitation was associated with cardiogenic shock in five (0.8%) of 623 patients with acute myocardial infarction who were urgently admitted to the authors' hospitals between 1994 and 1996. The infarct was located in the inferior wall in four patients and in the inferoposterior wall in one patient. Severe mitral valve regurgitation occurred concurrently with cardiogenic shock between one and six days after the onset of myocardial infarction. A mitral regurgitant murmur was not audible in four of five patients. Similarly, mitral regurgitant Doppler signals were not detected in four patients by transthoracic echocardiographic examination, while transesophageal echocardiographic examination detected mitral regurgitant signals clearly in all patients. Thus, when cardiogenic shock is unexpectedly associated with inferior or inferoposterior wall acute myocardial infarction, severe mitral regurgitation should be suspected, even when a mitral regurgitant murmur is not audible. Furthermore, mitral regurgitant flow signals may not always be detected by transthoracic echocardiography. Thus, examination for mitral regurgitation by transesophageal echocardiography should be considered.

Increased urinary excretion of macrophage-colony-stimulating factor (M-CSF) in patients with IgA nephropathy: tonsil stimulation enhances urinary M-CSF excretion

Upper respiratory tract infection including chronic tonsillitis is considered to be involved in the onset and/or the progression of IgA nephropathy. It is well known that deterioration of urinary findings occurs after episodes of upper respiratory tract infection in patients with IgA nephropathy. We previously showed that the expression of macrophage-colony-stimulating factor (M-CSF) is increased in the glomeruli of patients with IgA nephropathy and correlated with glomerular mesangial proliferation, suggesting that M-CSF plays an important role in the progression of IgA nephropathy. In the present study, we measured the serum and urinary concentrations of M-CSF in patients with IgA nephropathy associated with chronic tonsillitis. Furthermore, we evaluated the effects of the local provocation test of tonsils (mechanical tonsil stimulation) on the serum and urinary concentrations of M-CSF in the following three groups: (1) IgA nephropathy with severe mesangial proliferation, (2) IgA nephropathy with mild mesangial proliferation, and (3) patients with chronic tonsillitis without renal disease. The serum and urinary levels of M-CSF in the groups with severe and mild IgA nephropathy were significantly higher than those in the chronic tonsillitis group. The urinary M-CSF level but not the serum M-CSF level was positively correlated with the degrees of mesangial proliferation and glomerular M-CSF expression in the renal biopsy specimens. The urinary M-CSF concentration was significantly increased after tonsillitis stimulation in both mild and severe IgA nephropathy groups. Enhanced urinary excretion of M-CSF prolonged for 7 days after tonsil stimulation in the severe IgA nephropathy group; in contrast, the urinay M-CSF level was increased for only 2 days after tonsil stimulation in the mild IgA nephropathy group. The urinary M-CSF level was not changed in the chronic tonsillitis group after tonsil stimulation. The serum concentrations of M-CSF were not changed after tonsil stimulation in these three groups. Our present results suggest that tonsil stimulation contributes to the progression of IgA nephropathy via enhancement of glomerular production of M-CSF. The urinary excretion of M-CSF may be a useful predictor to evaluate the relevance of chronic tonsillitis to the disease and the indication of tonsillectomy in patients with IgA nephropathy.

[Detection of early hilar lung cancers with fluorescence bronchoscopy]

The development of fluorescence bronchoscopy has made it possible to diagnose locally superficial hilar lung cancers such as carcinoma in situ, and in some cases atypical squamous metaplasia thought to be precancerous lesions. The selection of a treatment modality can be difficult for early hilar lung cancers due to problems associated with multiple lung carcinomas and the large number of heavy smokers afflicted. Many patients also have decreased pulmonary function. If carcinoma in situ and microinvasive carcinomas can be detected early, it may be possible to treat them radically with a less invasive method than surgery, such as endoscopic laser therapy. Centrally arising squamous cell carcinoma of the tracheobronchial tree, especially in heavy smokers, is thought to develop in multiple stages from squamous metaplasia, to atypical squamous metaplasia, followed by carcinoma in situ, and finally invasive cancer. However, it is hoped that preventive medicine for lung cancer will be established whereby patients with localized atypical squamous metaplasia detected by fluorescence bronchoscopy can be carefully monitored and motivated to stop smoking, and also administered chemopreventive agents.

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.

Pharmacokinetic interactions between HIV-protease inhibitors in rats

The interactions of four HIV-protease inhibitors, ritonavir (RIT), saquinavir (SAQ), indinavir (IND) and nelfinavir (NEL), were examined by in vitro metabolic studies using rat liver microsomal fractions. The substrate concentrations employed were 0.75 approximately 12 microM, and the inhibitor concentrations were 2.5 approximately 60 microM. The metabolic clearance rates of SAQ, NEL and IND as determined by V(max)/K(m) were 170.9+/-10.9, 126.0+/-4.4 and 73.0+/-2.0 microL/min/mg protein, respectively. RIT was a potent inhibitor of the other three protease inhibitors, and the inhibition constants (K(i)) were 1.64 microM for SAQ, 0.95 microM for IND and 1. 01 microM for NEL. NEL was the second strongest inhibitor with a K(i) for NEL inhibition of IND metabolism of 2.14 microM. IND was the third strongest inhibitor with K(i)s of 2.76 microM for inhibition of NEL and 3.55 microM for inhibition of SAQ. As SAQ has the highest metabolic clearance rate, the K(i) for the SAQ inhibition of IND metabolism was high, 9.50 microM. Based on these in vitro results, drug interactions between NEL and IND or RIT were studied after oral administration to rats where the dose of each drug was 20 mg/kg. The C(max) and AUC of NEL were increased 3.6- and 8.5-fold by the co-administration with RIT. However, in contrast to co-administration of NEL and RIT, the effect of IND on the pharmacokinetics of NEL was negligible and the t(1/2) of NEL was not significantly increased by IND. Therefore, the combination of NEL and IND is recommended as a combination therapy for AIDS patients.

Physiologically based pharmacokinetics of KNI-272, a tripeptide HIV-1 protease inhibitor

The effects of dose on the pharmacokinetic characteristics of KNI-272 were evaluated in rats after intravenous (iv) administration. The plasma kinetics of KNI-272 were dose-independent within a dose range of 1.0 to 10.0 mg/kg. However, when the dose was increased to 50.0 mg/kg, the area under the plasma concentration-time curve (AUC)/dose significantly increased and the total plasma clearance (Cl(tot)) significantly decreased, possibly due to saturation of hepatic metabolism. On the other hand, the terminal elimination half-life (t(1/2,lambda(z))) was independent of dose. Using biochemical and physiological parameters obtained from in vitro and in vivo studies, we developed a physiologically based pharmacokinetic (PBPK) model for KNI-272 in rats in which concentration-dependent nonlinear hepatic metabolism (Michaelis-Menten type metabolism) was considered. Using this PBPK model, plasma KNI-272 concentration-time profiles were simulated. From these profiles it was demonstrated that the terminal elimination phase was proportional to the dose at lower doses. However, as the dose increased to 50.0 mg/kg, the simulated plasma concentrations at the terminal elimination phase increased more than the increase of dose in the same way as the observed data. Accordingly, the dose-dependent plasma kinetics observed after a 50.0 mg/kg dose was considered to be attributable in part to concentration-dependent hepatic metabolism in rats.

Metabolic characterization of a tripeptide human immunodeficiency virus type 1 protease inhibitor, KNI-272, in rat liver microsomes

KNI-272 is a tripeptide protease inhibitor for treating human immunodeficiency virus type 1 (HIV-1). In in vitro stability studies using rat tissue homogenates, KNI-272 concentrations in the liver, kidney, and brain decreased significantly with time. Moreover, in tissue distribution studies, KNI-272 distributed highly to the liver, kidney, and small intestine in vivo. From these results and reported physiological parameters such as the tissue volume and tissue blood flow rate, we considered the liver to be the main organ which takes part in the metabolic elimination of KNI-272. Then the hepatic metabolism of KNI-272 was more thoroughly investigated by using rat liver microsomes. KNI-272 was metabolized in the rat liver microsomes, and five metabolites were found. The initial metabolic rate constant (kmetabolism) tended to decrease when the KNI-272 concentration in microsomal suspensions increased. The calculated Michaelis-Menten constant (K(m)) and the maximum velocity of KNI-272 metabolism (Vmax), after correction for the unbound drug concentration, were 1.12 +/- 0.09 micrograms/ml (1.68 +/- 0.13 microM) and 0.372 +/- 0.008 microgram/mg of protein/min (0.558 +/- 0.012 nmol/mg of protein per min), respectively. The metabolic clearance (CLint,metabo), calculated as Vmax/K(m), was 0.332 ml/mg of protein per min. Moreover, by using selective cytochrome P-450 inhibitors and recombinant human CYP3A4 fractions, KNI-272 was determined to be metabolized mainly by the CYP3A isoform. In addition, ketoconazole, a representative CYP3A inhibitor, inhibited KNI-272 metabolism competitively, and the inhibition constant (Ki) was 4.32 microM.

Recovery of iodine-123 metaiodobenzylguanidine uptake associated with left ventricular functional recovery in a patient with dilated cardiomyopathy. Endomyocardial histological findings before and after the improvement of uptake

A 58-year-old man with idiopathic dilated cardiomyopathy was treated with incremental administration of a beta-blocker (metoprolol) and an angiotensin converting enzyme inhibitor (enarapril). The left ventricular end-diastolic dimension and ejection fraction improved in 8 months from 83.3 mm and 17.3% to 46 mm and 69%, respectively. The washout ratio and heart-to-mediastinum ratio depicted on the delayed image for iodine-123 metaiodobenzylguanidine 123I-MIBG) uptake improved from 61.7% and 1.34 to 23.1% and 1.85, respectively, in association with improvement of left ventricular indices. Successive endomyocardial biopsy specimens disclosed reduction of the degrees of vacuolation, staining irregularity, and deformity of myocyte cytoplasm and nucleus compared to the findings before therapy. In this patient with dilated cardiomyopathy 123I-MIBG scintigraphy was useful for the evaluation of the effects of therapy. We conclude that it may be informative in the estimation of the histopathological abnormalities of the myocardium.

Growth kinetics of animal cells immobilized within porous support particles in a perfusion culture

The growth kinetics of anchorage-independent animal cells [mouse myeloma MPC-11 (ATCC CCL 167)] immobilized within porous polyvinyl formal resin biomass support particles (BSPs; 3 x 3 x 3 mm cubes; mean pore diameter, 60 microns) was analyzed by measuring intracellular and extracellular lactate dehydrogenase (LDH) activities in a perfusion culture. First, the intracellular LDH content of cells immobilized within the BSPs was assayed in a shake-flask culture and found to remain almost comparable to that of non-immobilized cells in the exponential growth phase under static culture. Then, cells inoculated in the BSPs were grown in a continuous stirred-tank bioreactor. Using the LDH content of non-immobilized cells, the density of immobilized cells and the numbers of leaked and dead cells were evaluated, respectively, by the intracellular LDH activity of immobilized and leaked cells and the LDH activity in cell-free culture supernatant. In the initial period, immobilized cells exhibited exponential growth at a constant apparent specific growth rate; however, the actual specific growth rate, which takes into consideration cell death and cell leakage, decreased significantly. In the stationary phase, the actual specific growth rate maintained a constant but markedly lower value than during exponential growth.

High spatial resolution CT with a synchrotron radiation system

OBJECTIVE

We describe a monochromatic X-ray CT system using synchrotron radiation, which has been constructed employing a vertical wiggler beam line at the National Laboratory for High-Energy Physics in Tsukuba, Japan. This CT system was produced to facilitate examination of the microstructures of material and biological specimens.

MATERIALS AND METHODS

The system provides excellent contrast and has a spatial resolution capacity ranging from 2 to 100 mm. In this preliminary experiment, the images of the rat were obtained at 36-mm slice thickness and 33.2-keV X-ray energy.

RESULTS

The nasal cartilage, skull, and teeth of a live rat were clearly demonstrated with 36-mm spatial resolution.

CONCLUSION

Using a monochromatic X-ray CT system with synchrotron radiation, detailed structures of rat skull were imaged clearly.

Growth and death behaviour of anchorage-independent animal cells immobilized within porous support matrices

Growth and death of anchorage-independent animal cells entrapped within porous biomass support particles (BSPs) in static or shake-flask cultures were evaluated by comparison of enzyme activity with non-immobilized cells grown under static culture using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay and release of lactate dehydrogenase into the culture medium. Mouse myeloma MPC-11 (ATCC CCL 167) cells inoculated within porous polyvinyl formal resin BSPs (3 x 3 x 3 or 2 x 2 x 2 mm; mean pore diameter, 60 microns) grew exponentially at a specific growth rate comparable to that of non-immobilized cells in the initial period of incubation. Entrapped cells then reached the stationary phase with a cell density over 10(7) cells/cm3 BSP. The death rate of entrapped cells increased in response to the rise in viable cell density in the BSPs. Observation of viable cell distribution within the BSPs using MTT staining indicated that the cells concentrated within a thin outer shell of the BSPs with time. After the immobilized cells reached the stationary phase, penetration of cells into the outer shell ceased and heterogeneous distribution of cell density occurred in the viable cell layer in the shake-flask culture.

Nondwarf rice seedling bioassay for gibberellins

The use of nondwarf rice (Oryza sativa L.) cultivars treated with uniconazole as test plants for gibberellin (GA) bioassay instead of Tan-ginbozu dwarf rice variant was investigated. The sensitivity of six nondwarf rice cultivars to GAs was increased substantially by treatment of the seeds with uniconazole. The minimum detectable dose of a GA in the nondwarf cultivars treated with uniconazole was 1- to 1/10-fold of that in the nontreated Tanginbozu and 3- to 10-fold of that in uniconazole-treated Tanginbozu. The relative activity of several GAs on treated nondwarf rice cultivars was not largely different from that to Tan-ginbozu. Considering that seeds of nondwarf rice are available commercially, the nondwarf rice seedling assay would be useful as a simple assay for systematic analysis of GAs, and also as a routine teaching tool in high schools and universities.

Long-term cultivation of anchorage-independent animal cells immobilized within reticulated biomass support particles in a circulating bed fermentor

Long-term cultivation of anchorage-independent animal cells immobilized within porous biomass support particles (BSPs) using a gas-stirred circulating bed fermentor (CBF) was investigated. Inoculation of mouse myeloma MPC-11 (ATCC CCL 167) cells into reticulated polyvinyl formal resin BSPs (3 x 3 x 3 mm; mean pore diameter, 60 microns; porosity, 0.88) and the repeated batch culture of inoculated cells were performed under gentle circulation of BSPs, induced by sparging air from the base of the fermentor. The glucose uptake rate of cells decreased in the initial period just after the start of circulation, since a relatively large number of cells leaked from the BSPs. After that period, the uptake rate gradually increased and the leakage of cells diminished. In the meantime, when inoculated cells were incubated statically by introducing air into days before circulating the BSPs, glucose consumption became very rapid and cell density in the BSPs reached at least 10(7) cells/cm3 BSP. Thus, a long-term cultivation without significant leakage of cells and with high cell density in BSPs was successfully achieved in the CBF-BSP system.