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Kyoko Soejima

Publications and source records attributed to Kyoko Soejima.

29 records · Page 2Linked to original sources
PubMed2003

Nonionic contrast media are less nephrotoxic than ionic contrast media to rat renal cortical slices.

BACKGROUND: Nephrotoxicity induced by contrast media (CM) is well recognized. Nonionic CM with lower osmolality than that of conventional ionic CM have been developed in an effort to reduce toxicity. However, the nephrotoxic effects of nonionic CM have not been well evaluated. Although our previous experiments using rat renal cortical slices indicated that the direct cellular toxicity of nonionic CM is less than that of ionic CM, it was suggested that the less toxic effects of nonionic CM on the metabolic function of renal epithelial cells were in part attributable to the lower osmolality of nonionic CM. In the present experiment, the direct toxicity of nonionic CM on renal epithelial cells was compared with that of ionic CM under equiosmolar conditions, where the effects of osmotic pressure were excluded. METHODS: Rat renal cortical slices were incubated with several kinds of CM at 37 degrees C for 120 min. Diatrizoate and iothalamate were employed as ionic CM. Iopamidol and iohexol were employed as nonionic CM. The activities of N-acetyl-beta-D-glucosaminidase (NAG), gamma-glutamyltransferase (GGTP), and lactate dehydrogenase (LDH) released from the renal slices into the incubation buffer were determined in order to evaluate renal epithelial damage caused by CM. Gluconeogenesis, p-aminohippuric (PAH) acid accumulation and ATP content in rat renal slices were determined with a view to examine the inhibitory effects of CM on the metabolic function of renal epithelial cells. The toxic effects of nonionic CM were compared with those of ionic CM under equiosmolar conditions, where mannitol was added to the experimental groups containing nonionic CM in order to exclude the effects of osmotic pressure. RESULTS: A significant difference was generally not found with regard to enzyme release between ionic CM and nonionic CM plus mannitol. The inhibition of gluconeogenesis and PAH accumulation in rat renal slices by nonionic CM with mannitol was less than that by ionic CM. Although the ATP content was reduced by both ionic CM and nonionic CM plus mannitol, there was no significant difference between these two groups. CONCLUSIONS: The present experiments demonstrated that nonionic CM were less nephrotoxic than ionic CM with regard to the function of renal epithelial cells, including gluconeogenesis and PAH accumulation, under equiosmolar conditions. These differences in nephrotoxicity between ionic and nonionic CM cannot be fully attributable to differences in osmotic pressure.

Acetylglucosamine↗
PubMed2003

Relationship of slow conduction detected by pace-mapping to ventricular tachycardia re-entry circuit sites after infarction.

OBJECTIVES: This study sought to characterize the relationship of conduction delays detected by pace-mapping, evident as a stimulus to QRS interval (S-QRS) delay >or=40 ms, to ventricular tachycardia (VT) re-entry circuit isthmuses defined by entrainment and ablation. BACKGROUND: Areas of slow conduction and block in old infarcts cause re-entrant VT. METHODS: In 12 patients with VT after infarction, pace-mapping was performed at 890 sites. Stimulus to QRS intervals were measured and plotted in three-dimensional reconstructions of the left ventricle. Conduction delay was defined as >or=40 ms and marked delay as >80 ms. The locations of conduction delays were compared to the locations of 14 target areas, defined as the region within a radius of 2 cm of a re-entry circuit isthmus. RESULTS: Pacing captured at 829 sites; 465 (56%) had no S-QRS delay, 364 (44%) had a delay >or=40 ms, and 127 (15%) had a delay >80 ms. Sites with delays were clustered in 14 discrete regions, 13 of which overlapped target regions. Only 1 of the 14 target regions was not related to an area of S-QRS delay. Sites with marked delays >80 ms were more often in the target (52%) than sites with delays 40 to 80 ms (29%) (p < 0.0001). CONCLUSIONS: Identification of abnormal conduction during pace-mapping can be used to focus mapping during induced VT to a discrete region of the infarct. Further study is warranted to determine if targeting regions of conduction delay may allow ablation of VT during stable sinus rhythm without mapping during VT.

Age Factors↗
PubMed2003

Inhibition of gluconeogenesis and p-aminohipuric acid accumulation in rat renal cortical slices by ionic and nonionic contrast media.

BACKGROUND: Renal dysfunction is a well-recognized complication induced by contrast media (CM). Nonionic CM have been introduced into clinical use to replace conventional ionic CM in an effort to reduce toxicity. However, the nephrotoxic effects of nonionic CM have not been fully evaluated. We previously determined the activities of N-acetyl-beta- d-glucosaminidase and gamma-glutamyltransferase released from rat and human renal slices incubated with contrast media. Dose-dependent enzyme release from renal slices was observed, but there was no statistical difference in the increase of enzyme activities between ionic and nonionic CM. The present experiment was conducted to compare the effects of ionic and nonionic CM on the metabolic function of rat renal slices. METHODS: Rat renal cortical slices were incubated with ionic CM (diatrizoate, iothalamate) and nonionic CM (iopamidol, iohexol) at 37 degrees C for 90 min. To examine the dose-response effects of CM on gluconeogenesis and p-aminohipuric acid (PAH) accumulation in the rat renal slices, slices were incubated with 30, 60, and 90 mg I/ml of CM. The inhibitory effects of nonionic CM on gluconeogenesis and PAH accumulation were compared with those of ionic CM in an independent experiment, in which slices were incubated with CM at a concentration of 60 mg I/ml. In addition, rat renal slices were incubated with mannitol instead of CM to investigate the effects of osmotic pressure on gluconeogenesis and PAH accumulation. RESULTS: A dose-dependent reduction of gluconeogenesis in rat renal slices was demonstrated by both ionic CM and nonionic CM. The inhibition of PAH accumulation was dose-dependent with nonionic CM, but not with ionic CM. Gluconeogenesis and PAH accumulation within the renal slices were both inhibited according to the increase in osmotic pressure produced by mannitol. The reduction in gluconeogenesis and PAH accumulation within the rat renal slices incubated with 60 mg I/ml of nonionic CM were significantly less than those resulting from the same concentration of ionic CM. CONCLUSIONS: Nonionic CM is less nephrotoxic than ionic CM with regard to gluconeogenesis and PAH accumulation in rat renal slices. These differences in nephrotoxic effect between ionic and nonionic CM may in part be attributable to differences in osmotic pressure.

Animals↗
PubMed2003

Catheter ablation of ventricular tachycardia in patients with ischemic heart disease.

Radiofrequency ablation is a valuable adjunctive therapy to implantable defibrillators in patients with recurrent monomorphic ventricular tachycardia (VT) after myocardial infarction. Episodes of VT are markedly reduced in most patients, and the major complications are less than 5%. Newer approaches allow successful ablation even when VT is unstable, and when multiple VTs are present. Epicardial mapping and ablation are needed in some patients. Continued advances in technology can be expected to further improve results.

Catheter Ablation↗
PubMed2003

Device to promote pelvic floor muscle training for stress incontinence.

AIM: Many patients with stress urinary incontinence do not have enough motivation to continue pelvic floor muscle training (PFMT) by themselves. Therefore, a device was created to support PFMT, and its effect was examined. METHODS: Forty-six women with stress urinary incontinence were assigned to a control group or a device group in order of presentation. A pamphlet on PFMT was given to control patients, while the same pamphlet plus the device and instructions on its use were given to patients in the device group. The device had a chime that was set to sound three times a day when exercise sessions were scheduled. PFMT consisted of fast and slow pelvic floor muscle contraction exercises that were performed for 2 min and followed a rhythm set by the device. RESULTS: After 8 weeks, 20 patients from the control group and 21 patients from the device group could be evaluated. In the control group, only the quality of life (QOL) index improved significantly. In the device group, however, the daily number of incontinence episodes, the number of pads used daily, the QOL index, and the pad weight in the pad test improved significantly. Patients in the device group said that they felt obligated to perform PFMT when the chime sounded. Forty-eight percent of patients from the device group were satisfied with the outcome of PFMT, while only 15% were satisfied in the control group. CONCLUSION: This device may be useful to support the management of stress urinary incontinence.

Adult↗
PubMed2003

Assessment of radiofrequency ablation effect from unipolar pacing threshold.

Methods for determining if an ablation lesion has been created by RF current application are limited, but needed. This study sought to determine if a change in pacing threshold at the ablation site might be used to assess creation of an ablation lesion. Peak-to-peak amplitude of the bipolar electrogram (EGM) and the unipolar pacing threshold were determined before and after creation of RF lesions using irrigated tip (63 lesions in 11 patients) or conventional ablation catheters (33 lesions in 9 patients) in infarct scars for ablation of ventricular tachycardia. The threshold was measured during continuous pacing at a cycle length of 600 ms by a decrementing output current at a pulse width of 2 ms. The unipolar pacing threshold increased by 254 +/- 248% (from 5.7 +/- 3.5 to 15.1 +/- 6.7 mA, P<0.001) after irrigated tip ablation and by 155 +/- 144% (from 5.9 +/- 3.4 to 12.3 +/- 5.7 mA, P<0.001) after conventional ablation (P<0.05 for irrigated tip vs conventional). EGM amplitude decreased by 17 +/- 27% (from 0.39 +/- 0.32 to 0.30 +/- 0.21 mV) after irrigated tip ablation and by 16 +/- 24%(from 0.48 +/- 0.27 to 0.41 +/- 0.20 mV) after conventional ablation (irrigated tip vs conventional, P=NS). There was no correlation between the change in bipolar EGM amplitude and the pacing threshold. An increase in unipolar pacing threshold is a marker of lesion creation. In regions of infarction, the relative change in threshold produced by ablation is substantially larger than the change in bipolar electrogram amplitude. The greater increase in pacing threshold after irrigated tip ablation compared to conventional ablation suggests that the magnitude of change reflects lesion size.

Aged↗
PubMed2002

Electrically unexcitable scar mapping based on pacing threshold for identification of the reentry circuit isthmus: feasibility for guiding ventricular tachycardia ablation.

BACKGROUND: We hypothesized that delineating electrically unexcitable scar (EUS) within low-voltage infarct regions will locate reentry circuit isthmuses by defining their borders. The pacing threshold and electrogram amplitude that best determines EUS is unknown. METHODS AND RESULTS: The change in dimension of the virtual electrode was estimated in 11 patients and observed to increase by 4.4+/-2.5 mm as stimulus strength increases from threshold (2.9+/-1.8 mA) to 10 mA. EUS was defined as a threshold >10 mA. In 14 consecutive patients, mapping and ablation of ventricular tachycardia (VT) were performed using an electroanatomic mapping system. During sinus rhythm, unipolar pacing was performed at sites with bipolar electrogram amplitude <1.5 mV. EUS regions were marked on the maps. Reentry circuit isthmuses were identified by entrainment mapping or pace mapping, and ablation was performed. EUS was identified in the infarct in all 14 patients (11.8+/-13.9 cm2). All 20 VT circuit isthmuses identified were adjacent to EUS. Although electrogram amplitude correlated with pacing threshold (r=0.64, P<0.0001), many isthmuses had very low-amplitude electrograms, and EUS could not be identified from electrogram amplitude alone. RF ablation lines connecting selected EUS regions abolished all inducible VTs in 10 patients (71%); spontaneous VT was markedly reduced during follow-up (from 142+/-360 to 0.9+/-2.0 episodes per month, P=0.002). CONCLUSIONS: This new method of identifying EUS provides complimentary information to the electrogram amplitude in delineating potential reentry circuit paths, potentially facilitating ablation during sinus rhythm.

Aged↗
PubMed2002

Effect of radiofrequency catheter ablation of ventricular tachycardia on left ventricular function in patients with prior myocardial infarction.

INTRODUCTION: Successful RF ablation of VT late after MI can involve multiple applications and long lines of RF lesions. The impact on left ventricular function is potentially important, but not well defined. Quantitative echocardiography was used to determine the effect of radiofrequency (RF) ablation on left ventricular function in patients with ventricular tachycardia (VT) after myocardial infarction (MI). METHODS AND RESULTS: In 62 patients (55 men; age 67 +/- 1.1 yr.) who underwent RF ablation for VT late after MI, left ventricular ejection fraction (LVEF) was quantified from digitized echocardiograms performed </=1 week before and <72 hours after ablation. Patients received a mean of 25.6 +/- 2.2 (range of 3-98) RF lesions. The LVEF pre- and post-ablation did not differ for the group (pre-LVEF 29.8 +/- 11.9% vs. post-LVEF 29.5 +/- 11.2%, p = 0.626), or for the 30 patients who received >25 RF lesions (Pre-LVEF 28.5 +/- 11.1% vs. Post-LVEF 28.1 +/- 10.8%, p = 0.74) or for the 7 patients who received >40 RF lesions (Pre-LVEF 29.9 +/- 12.7% vs. Post-LVEF 29.2 +/- 6.2%, p = 0.84). Although LVEF did not change for the group, LVEF increased >5% in 12/62 (19.4%) pts and decreased >/=5% in 14/62 (22.5%) pts. Patients with a decrease in EF did not differ from the remaining patients with respect to age, gender, number of RF lesions, or use of a cooled RF catheter, but did have a better initial EF (38.8 +/- 12.2% versus 27.2 +/- 10.6%, p = 0.001). CONCLUSION: Multiple RF ablation lesions confined to infarct regions do not measurably affect LV function, but a cautious approach, confining ablation lesions to areas of scar, as was attempted in this study, seems prudent.

Aged↗
PubMed2002

Hand-assisted retroperitoneoscopic nephroureterectomy for upper urinary-tract urothelial tumors.

PURPOSE: We report our experience with hand-assisted retroperitoneoscopic nephroureterectomy for upper urinary-tract urothelial cancer. PATIENTS AND METHODS: Our initial 10 cases of clinical stage T(1)N(0)M(0) renal pelvic and ureteral tumors treated with hand-assisted retroperitoneoscopic nephroureterectomy are included in the present report. Nephrectomy was conducted retroperitoneoscopically with hand assistance via a lower-abdominal midline incision. Resection of the lower ureter together with the bladder cuff was performed as open surgery and the specimen was removed en bloc via the same incision. RESULTS: Hand-assisted retroperitoneoscopic nephroureterectomy was completed successfully in all 10 cases. The mean operating time was 456 +/- 90 minutes, and the mean estimated blood loss was 462 +/- 364 mL. The times to oral intake and walking were 1.5 +/- 0.5 days and 2.3 +/- 0.7 days, respectively. One case of renal vein injury, one case of pulmonary embolism, and three cases of wound infection were the complications. CONCLUSION: This is the first report of hand-assisted endoscopic nephroureterectomy using the retroperitoneal approach. The surgical technique seems quite reasonable because the lower-abdominal incision can be utilized, not only as a route for hand assistance, but also as a window for open surgery when resecting the distal ureter as well as for extracting the surgical specimen.

Aged↗