Cine magnetic resonance imaging provides novel predictors of early continence recovery after radical prostatectomy: Assessment of the dynamics of pelvic floor muscles.

AIMS: Postprostatectomy incontinence is a major complication of prostatectomy. Although pelvic floor muscle training can successfully treat postprostatectomy incontinence, evidence for how muscle movement affects continence recovery is lacking. We evaluated dynamic factors of prostatectomy patients using cine magnetic resonance imaging to identify risk factors for postprostatectomy incontinence and reveal the contribution of pelvic floor muscles to continence recovery. METHODS: A total of 128 prostate cancer patients who underwent robot-assisted laparoscopic surgery were enrolled. Cine magnetic resonance imaging was performed preoperatively and 6 months after surgery. Continence was defined as pad-free or use of safety pads. We defined the bladder neck elevation distance during pelvic floor muscle training as the bladder elevation distance. Patients with continence recovery within 1 month comprised the continence group (n = 48); other patients comprised the incontinence group (n = 80). RESULTS: The preoperative bladder elevation distance was significantly longer in the continence group than in the incontinence group (10.4 vs. 8.2 mm; p < .001). The postoperative bladder elevation distance of the continence group tended to be longer (9.9 vs. 8.9 mm; p = .057). Multivariate analysis showed that the preoperative bladder elevation distance significantly contributed to continence recovery (p = .016). Patients with a longer preoperative bladder elevation distance (>8.5 mm) experienced continence recovery significantly faster than patients with a shorter distance (<8.5mm) (p = .038). CONCLUSIONS: Bladder elevation distance, a novel dynamic parameter, was strongly associated with early continence recovery. Cine magnetic resonance imaging can assess a patient's risk of postprostatectomy incontinence and guide pelvic floor muscle training.

[EVALUATING THE RELATIONSHIP BETWEEN LOWER URINARY TRACT SYMPTOMS AND ENDOTHELIAL FUNCTION USING FLOW-MEDIATED DILATION, AND THE EFFECTS OF TADALAFIL].

(Objective) Recently, lower urinary tract symptoms (LUTS) were reported to be associated with endothelial dysfunction. Endothelial function is non-invasively measured by flow-mediated dilation (FMD). As tadalafil has the potential to improve atherosclerosis, we evaluated the relationship between LUTS and endothelial function using FMD, and the effects of tadalafil. (Patients and methods) We conducted FMD examinations for a total of 122 males, and analyzed its association with IPSS, OABSS, and cardiovascular risks. Furthermore, 21 BPH patients received 5 mg of tadalafil per day for one year. We defined the Low FMD group as FMD < 3.9% and the Control group as other values, and compared the effects of tadalafil between groups. (Results) In the 122 male patients, FMD was negatively correlated with nocturia and OABSS. Patients with hypertension or coronary artery disease had a lower FMD than those without.In the tadalafil administration study, the Low FMD group achieved greater improvement of IPSS, OABSS and FMD than the Control group. (Conclusion) FMD examination revealed that endothelial dysfunction is closely associated with LUTS in males, and that tadalafil is effective for patients with endothelial dysfunction.

[THE 10-YEAR OUTCOMES OF PVP (PHOTOSELECTIVE VAPORIZATION OF THE PROSTATE) FOR TREATING BPH (BENIGN PROSTATIC HYPERPLASIA)].

(Purpose) Photoselective vaporization of the prostate (PVP) was introduced in Japan about 10 years ago, and there has been few studies regarding long-term outcomes so far. Herein we report our 10-year follow up result of PVP. (Patients and methods) From January 2006 to June 2006, 31 patients with benign prostatic hyperplasia (BPH) underwent PVP and 20 patients were evaluable in 10 years after PVP. Patients were evaluated preoperatively, at 6 months and at 10 years after surgery by International Prostate Symptom Score (IPSS) and Quality of life score (QOL score). The surgery used 80 watt potassium-titanyl-phosphate laser that was an old model. (Results) The mean IPSS preoperatively, at 6 months and at 10 years was 21.1, 5.5 and 9.4, respectively. The mean QOL score preoperatively, at 6 months and at 10 years was 5.3, 2.2 and 2.5, respectively. Both IPSS and QOL score were significantly improved at 6 months and at 10 years compared with preoperatively. However, among 20 patients re-operation for residual adenoma was required in 4 patients (20%) during the follow-up period. (Conclusion) PVP is an effective method for BPH treatment, allowing sustained long-term improvement of the voiding function.

Sufficient Volume Ablation with Photoselective Vaporization of the Prostate Delivers 5-Year Durability and Improves Symptom Relief for Larger Prostates.

OBJECTIVES: To assess the long-term durability of photoselective vaporization of the prostate (PVP) for symptomatic benign prostatic enlargement (BPE) or benign prostatic obstruction (BPO) and treatment efficacy for large BPE. METHODS: Four hundred fifty-seven patients with symptomatic BPE underwent PVP between January 2006 and April 2009. Efficacy was evaluated with the International Prostate Symptoms Score (IPSS), Quality of Life (QOL) score, urinary peak flow (Qmax), postvoid residual volume (PVR), and prostate volume. Parameters were checked preoperatively, and at 1, 3, and 5 years postoperatively. One hundred fifty-three patients completed 5-year follow-up. To assess treatment effects, patients were divided into two groups according to the preoperative prostate volume: group A (<60 mL, n=104) and group B (>60 mL, n=49). RESULTS: Mean IPSS, QOL score, Qmax, and PVR improved significantly and were maintained for 5 years with no significant differences; at year 1, prostate volume had decreased significantly from 54.0 mL to 30.6 mL (43% of volume ablation) and remained at that level until year 5. Investigations according to prostate size demonstrate that IPSS and QOL scores in group B remained at significantly lower levels, and Qmax in group B improved more than in group A. 1.1% of patients needed transurethral resection of the prostate due to BPO recurrence. CONCLUSIONS: PVP is effective and provides durable results for 5 years, with sustained symptom relief and improved urinary flow rate, as well as a 43% volume reduction of prostate volume. Our data indicate PVP is more efficacious for larger prostates under sufficient volume ablation.

[MODIFICATIONS FOR CONTROLLING THE DORSAL VEIN COMPLEX IN ROBOTIC-ASSISTED LAPAROSCOPIC RADICAL PROSTATECTOMY].

OBJECTIVE: To investigate a superior method for controlling the dorsal vein complex (DVC) in robotic-assisted laparoscopic radical prostatectomy at Nagakubo hospital. PATIENTS AND METHODS: DVC control was altered from suture ligation followed by DVC division (SL group, n = 115) to preceding division followed by suture (PD group, n = 62). Surgical margin status and functional outcomes were investigated. RESULTS: No notable surgical complications were found in the PD group. Operation time and estimated blood loss were significantly less in the PD group; however, changes to serum hemoglobin before and after surgery showed no significant difference. The rates of positive surgical margin were 26.1% and 11.3% in the SL and PD groups, respectively (p = 0.021). Apical margin positivity was 9.6% and 3.2% in the SL and PD groups, respectively (p = 0.12). Urinary continence outcomes of within one pad/day and pad free in the SL and PD groups until 6 mo after surgery were 93.6% and 89.1% (P = 0.21), and 67.3% and 67.5% (p = 0.96), respectively. Erection recovery within 6 mo was 43.6% and 41.7% in the SL and PD groups (p = 0.91). CONCLUSION: Preceding division followed by suture method decreased apical margin positivity and provided superior cancer control in comparison with suture ligation followed by DVC division, although, it was probably influenced by the learning curve. Functional outcomes were not significantly different with either method.

Safety and efficacy of teneligliptin: a novel DPP-4 inhibitor for hemodialysis patients with type 2 diabetes.

PURPOSE: Teneligliptin is a novel DPP-4 inhibitor in development for treating type 2 diabetes mellitus that does not require dose adjustment for diabetic patients with end-stage renal disease; however, it had not been known whether or not teneligliptin is safe or potent in dialysis patients. We conducted a prospective study to assess the utility of teneligliptin for diabetic patients undergoing hemodialysis. METHODS: Blood glucose, glycated albumin, and HbA1c were measured every 4 weeks, at 4, 12, 20, and 28 weeks, and every 8 weeks, respectively, for patients treated with teneligliptin (n = 14; 7 patients newly started and 7 that switched from other medications) and patients of a control group who continued ongoing antidiabetic therapy (n = 29). RESULTS: Blood glucose level showed a 36.7 mg/dl decrease from 4 weeks in the teneligliptin group (p < 0.05). The differences in glycated albumin (at 28 w) and HbA1c (at 24 w) between the teneligliptin group and the control group were -3.1 % (p < 0.05) and -0.57 % (p = 0.057), respectively. These parameters also decreased in patients who switched from voglibose 0.2 mg t.i.d. or vildagliptin 50 mg qd after teneligliptin administration. No case with hypoglycemia was identified. One patient had the dose of a laxative administered for constipation increased; however, no patient ceased teneligliptin due to side effects. CONCLUSION: Teneligliptin 20 mg is well tolerated, safe, and significantly improves glycemic control in diabetic patients with end-stage renal disease. Teneligliptin 20 mg once daily was considered to be more potent than voglibose 0.2 mg t.i.d. or vildagliptin 50 mg qd.

[Comparison of initial results with robotic-assisted laparoscopic radical prostatectomy and open retropubic radical prostatectomy].

OBJECTIVE: To investigate the superiority in 2 radical prostatectomies, we compared the initial results of robotic-assisted radical prostatectomy (RARP) to those of retropubic radical prostatectomy (RRP) performed during the same period at Nagakubo hospital. PATIENTS AND METHODS: The study was conducted on a total of 160 patients having undergone radical prostatectomy from April 2009 to March 2012 (92 patients with RARP and 68 with RRP). We investigated surgical stress, cancer control, functional outcomes and complications in both groups. RESULTS: Surgical stress; operation time was significantly shorter with RRP; however, blood loss and serum total protein loss were significantly less with RARP. White blood cell count at 2 days after surgery was significantly less with RARP. The rates of analgesic use and SIRS were similar. Although the date on which taking solid meals resumed did not differ, the duration of indwelling urethral catheter and admission period were significantly shorter with RARP. Cancer control; the rates of positive surgical margin were 27.2% and 19.1% with RARP and RRP, respectively (p = 0.24), and biochemical recurrence was seen in 12.0% and 19.1% with RARP and RRP, respectively (p = 0.73), which were not significantly different. Continence; urinary continence outcomes with RARP and RRP were 17% and 4% for urinary continence at discharge (p = 0.01), 1.8 and 3.3 months for no more than one pad per day (p < 0.01), and 4.3 and 6.2 months for pad free (p = 0.03), respectively. Sexual function; erection recovery within 6 mo was only observed with RARP; however, overall recovery rate of erection was 65% and 75% with RARP and RRP, respectively (p = 0.69). COMPLICATIONS: 1 case with a rectal injury was seen in both groups, but complication rates were 8.7% and 16.2% with RARP and RRP, respectively (p = 0.22). CONCLUSION: In spite of our initial experience of RARP, surgical stress and complications with RARP were considered to be superior to that with RRP. Cancer control and sexual function showed no significant difference between RARP and RRP, however, urinary continence outcome is significantly superior with RARP. Our data suggest that treatment outcome after initial experience with RARP is not inferior to that with RRP, and better results are expected by improving surgical techniques.

ß3-Adrenoceptor agonist mirabegron is effective for overactive bladder that is unresponsive to antimuscarinic treatment or is related to benign prostatic hyperplasia in men.

PURPOSE: To investigate the safety and efficacy of mirabegron for patients with overactive bladder (OAB) that is unresponsive to antimuscarinic agents or is related to benign prostatic hyperplasia (BPH). METHODS: Fifty-two newly diagnosed OAB patients (M group) and 45 patients with OAB that was unresponsive to antimuscarinics (S group) received mirabegron 50 mg once daily and were evaluated by OAB symptom score (OABSS), IPSS-QOL index, and IPSS at the time of baseline, 4 and 8 weeks. Newly diagnosed OAB patients treated with antimuscarinic agents were compared as controls. RESULTS: Mirabegron was effective for 85.2 % in M group. Significant improvements were seen in each domain of OABSS, and there was no significant difference with antimuscarinic therapy. Mirabegron was efficacious for 61.6 % of S group, and significant decreases of OABSS and IPSS-QOL index were observed. Significant improvements were also seen in voiding symptoms in men. Post-void residual urine volumes before and after treatment were 32.1 and 34.8 ml, and 26.2 and 31.3 ml in M and S group, respectively, and there was no significant difference. The incidence of adverse events was 8.4 %, although none were serious, and the patients recovered spontaneously after mirabegron was discontinued. CONCLUSION: The present study suggests mirabegron is as effective as antimuscarinics for OAB. It improves OAB symptoms in patients with OAB for which antimuscarinic agents are insufficient. This study revealed that mirabegron improves not only OAB symptoms related to BPH, but also voiding symptoms in men. Low and mild incidences of side effects support the safe utility of mirabegron.

Transurethral resection in saline vaporization: evaluation of clinical efficacy and prostate volume.

OBJECTIVE: To assess the efficacy and safety of transurethral resection in saline vaporization for symptomatic bladder outlet obstruction and the change in prostate volume. METHODS: A total of 106 patients with symptomatic bladder outlet obstruction underwent transurethral resection in saline vaporization. The effectiveness of the treatment was evaluated using the International Prostate Symptom Score (IPSS), quality of life score, urinary peak flow, and prostate volume preoperatively and at 1, 3, 6, and 12 months postoperatively. To assess the treatment effect, the patients were divided into 3 groups according to the preoperative prostate volume: group 1 (<45 cm(3), n = 40), group 2 (≥ 45 but <65 cm(3), n = 34), and group 3 (≥ 65 cm(3), n = 32). RESULTS: The mean perioperative hemoglobin loss was 1.2 g/dL. The mean IPSS, quality of life score, and prostate volume decreased significantly from 24.3, 5.2, and 52.8 cm(3) to 11.1, 2.7, and 29.9 cm(3), respectively (P < .01) and the mean urinary peak flow had increased significantly from 7.3 to 15.1 (P < .01) at 1 month. Moreover, the IPSS, quality of life score, and prostate volume had significantly decreased to 8.8, 2.3, and 26.1 cm(3) at 3 months (P < .05). The investigation of groups classified by prostate size demonstrated that the IPSS in group 3 continued at a significantly lower level than that in groups 1 and 2. The prostate volume decreased gradually and resulted in 52.8% volume reduction for ≤ 12 months. No significant complications were seen; however, irritative symptoms occurred frequently (11.3%). CONCLUSION: Transurethral resection in saline vaporization was a safe and effective treatment option and was more efficacious for patients with a larger prostate. The bother scores and prostate volume gradually decreased for ≤ 12 months.

Photoselective vaporization of the prostate: pursuing good indications based on the results of 400 Japanese patients.

OBJECTIVE: To investigate good indications of photoselective vaporization of the prostate (PVP) by retrospective evaluation of its efficacy in relation to prostate volume. PATIENTS AND METHODS: A cohort of 400 patients had International Prostate Symptoms Score (IPSS), Quality of Life (QoL) score, urinary peak flow (Q(max) ), and prostate volume (P(vol) ), assessed before and after surgery. Changes of outcome variables were compared among four groups classified according to preoperative prostate volume: <30 mL (group A), ≥30 and <50 mL (group B), ≥50 and <70 mL (group C), and >70 mL (group D). RESULTS: Operating times and amounts of energy applied were 44.2 min and 159 kJ, 67.7 min and 268 kJ, 111 min and 409 kJ, and 171 min and 604 kJ in groups A, B, C, and D, respectively. All variables improved significantly and immediately, and remained for more than 12 months. Investigation of groups classified by prostate size demonstrated that IPSS and QoL score decreased and improvement rate of Q(max) rose as prostate volume increased. Changes of P(vol) were from 24.5 mL to 13.2 mL (-46.1%), from 39.8 mL to 22.9 mL (-42.4%), from 58.4 mL to 32.8 mL (-43.8%), and from 92.1 mL to 53.8 mL (-41.5%) in groups A, B, C, and D, respectively. Overall the P(vol) reduction rate was 43.2%, and no significant differences were observed in reduction ratios among the groups. Complications were minimal, but bladder neck contracture arose in 16 cases with a smaller prostate. CONCLUSION: Whilst the percentage reduction in volume was similar across the groups, the larger absolute volume reduction in patients with larger prostates was associated with greater improvement in objective urinary function variables, and with symptom score reduction.

[Clinical importance of guideline for decontamination of endoscopes in urological field: verification of 3 processes].

UNLABELLED: Clinical guideline for decontamination of endoscopes in urological field has not been provided, although endoscopic examination should be done in aseptic circumstance. MATERIAL AND METHOD: From decontamination processes, following 3 points were selected for verification: 1) Volume of residual water in flexible scope after rinsing, estimated by weight change. 2) Concentration of eluted disinfectant from flexible scope after standard rinsing procedure for gastrointestinal endoscope. 3) Observation of possible damage of telescope, caused by repeat autoclaving. RESULTS: Wet condition of flexible scope could be suspected in 60 hours in room temperature. Eluted disinfectants were detected, but in harmless level. Repeated autoclaving merely caused minor damage, which does not interfere clinical use. CONCLUSION: We obtained a couple of evidences with cautions in decontamination processes for endoscopes. Urgent requirement of standardization in this field should be discussed widely.

Ectopic thyroid in an adrenal mass: a case report.

BACKGROUND: It is difficult to explain ectopic thyroid beneath the diaphragm because during the development the thyroid descends from the tongue to the anterior of the trachea. A few cases of ectopic lesions have been reported in the literature for abdominal organs including the adrenal glands, but the mechanism by which the thyroid components migrate into the abdomen has been poorly understood. CASE PRESENTATION: A 54-year-old woman was diagnosed as having an adrenal mass. Laparoscopic adrenalectomy was carried out. Microscopically, the mass was composed of normal adrenal and ectopic thyroid tissues. CONCLUSION: We herein describe the fourth case reported of ectopic thyroid in the adrenal gland.

A simple organic reaction mediates the crystallization of the inorganic nanocluster [Ga13(mu3-OH)6(mu2-OH)18(H2O)24](NO3)15.

We report the single-crystal structure of an inorganic gallium cluster [Ga13(mu3-OH)6(mu2-OH)18(H2O)24](NO3)15.6H2O prepared using a simple organic reaction to drive the formation of the crystalline inorganic cluster.

Testicular seminoma after the complete remission of extragonadal yolk sac tumor : a case report.

BACKGROUND: Between 2% and 5% of malignant germ-cell tumors in men arise at extragonadal sites. Of extragonadal germ cell tumors, testicular carcinoma in situ (CIS) are present in 31-42% of cases, and CIS are reported to have low sensitivity to chemotherapy in spite of the various morphology and to have a high likelihood of developing into testicular tumors. A testicular biopsy may thus be highly advisable when evaluating an extragonadal germ cell tumor. CASE PRESENTATION: A 36-year-old man was diagnosed as having an extragonadal non-seminomatous germ cell tumor, that was treated by cisplatin-based chemotherapy, leading to a complete remission. In the meantime, testicular tumors were not detected by means of ultrasonography. About 4 years later, a right testicular tumor was found, and orchiectomy was carried out. Microscopically, the tumor was composed of seminoma. CONCLUSIONS: We herein report a case of metachronous occurrence of an extragonadal and gonadal germ cell tumor. In the evaluation of an extragonadal germ cell tumor, a histological examination should be included since ultrasonography is not sufficient to detect CIS or minute lesions of the testis.

Nephrotic syndrome as a result of membranous nephropathy caused by renal cell carcinoma.

A 77-year-old woman was admitted for a renal biopsy to evaluate a case of nephrotic syndrome. In the course of the examination, a right renal tumor was incidentally found. We performed a right radical nephrectomy in advance of the renal biopsy. Histologically, the tumor was diagnosed as a renal cell carcinoma (clear cell carcinoma) and the non-neoplastic renal cell tissue showed membranous nephropathy (MN). After surgery, the nephrotic syndrome remitted without any further medical treatment and the MN was considered to be a malignancy associated syndrome. There have been few case reports in the literature regarding this association and we wish to describe another case.

Hypercalcemia upon recurrence of renal cell carcinoma producing parathyroid hormone-related protein.

We established a new renal carcinoma cell line that produces parathyroid hormone-related protein (PTHrP) and interleukin-6 in culture. The cellular production of PTHrP was confirmed by Northern blot analysis and immunofluorescence examination. Bone and lung metastases occurred simultaneously 3.5 years after surgery. The patient did not show hypercalcemia at this time, despite the presence of multiple osteolytic metastases. About 7 months after bone metastasis was first shown, serum PTHrP was detected by means of an immunoradiometric assay and the calcium level was found to be elevated to 3.29 mmol/l. The hypercalcemia was successfully controlled by i.v. administration of bisphosphonates.

[Ureteral stricture after ESWL for ureteral calculi].

BACKGROUND: There are many reports on the effects of ESWL, but few reports on the complications, especially remaining ureteral stricture after this treatment. Therefore we have retrospectively reviewed our cases to define the predisposing factors of this complication. METHODS: Since 1991 we have treated urolithiasis with ESWL using a Siemens Lithostar for the first therapy. We had 16 cases of ureteral stricture after this treatment. Ureteral stricture is the most common complication after ESWL treatment. To define the risk factor of the stricture we have compared 549 cases that were successfully treated between 1994 and 1996 without this complication. In these two groups we examined ages, sexes, chief complaints, size, position and components of the calculi, the degree of hydronephrosis, the frequency of ESWL, the presence of urinary tract infection, the duration of stone impaction and the after endourological treatment using multiple logistic regression analysis. RESULTS: Patients with the stone incidentally found and those with the UTI seemed to be more frequently associated with ureteral stricture, however there was not a significant difference. The hydronephrosis more than grade 3 (p = 0.025), the frequency of ESWL (p = 0.0325) and the after endourological treatment, especially TUL (p = 0.0184) were statistically significant among the other factors. The stricture occurred in 5 out of 29 patients with the hydronephrosis of grade 4 and 5 between 1994 and 1996. CONCLUSION: We should carefully treat patients with grade 3 or more hydronephrosis with ESWL. We should not repeatedly treat the patients with ESWL. We should take care of TUL treatment after ESWL.

Diversity of inhibitory responses to beta2-stimulants shown by term-pregnant human myometria in vitro is partly due to differences in receptor density.

OBJECTIVE: The aims of this study were (1) to evaluate the usefulness of the new beta2-adrenergic stimulant KUR-1246 as a tocolytic agent and (2) to clarify the mechanisms that underlie the diverse inhibitory effects of beta2-stimulants that are seen in human myometria in vitro. STUDY DESIGN: The displacement of tritiated ([3H]) (-)CGP 12177 (0.4 nmol/L) by KUR-1246 and other beta2-stimulants was examined with human beta(1)- and beta2-receptors present on membrane fractions. The inhibitory effects of these beta2-stimulants on the term-pregnant human myometrium were compared with the use of isometric tension recording and microelectrode methods. Finally, the relationship between [3H]dihydroaloprenolol binding and the magnitude of the tocolytic effect of isoproterenol was examined. RESULTS: KUR-1246 was approximately 80 times and 7 times more selective for beta2-receptors than isoproterenol and ritodrine, respectively. The inhibitory effect of KUR-1246 was as strong as the inhibitory effect of the conventional beta2-adrenergic stimulants. A wide range of inhibitory effects was observed, even when high concentrations of isoproterenol or KUR-1246 were applied. There was a correlation between the degree to which isoproterenol suppressed contractions and the number of [3H]dihydroaloprenolol binding sites on the membrane in each muscle strip. CONCLUSION: KUR-1246 should be a very useful beta2-adrenergic stimulant for use as a tocolytic agent because of its high selectivity for the beta2-receptor and its potent inhibitory effect. The diversity of the inhibitory effects that are induced by beta2-stimulants is at least partly due to differences in beta2-receptor density among term-pregnant human myometria.

Real-time kinetic analyses of the interaction of ricin toxin A-chain with ribosomes prove a conformational change involved in complex formation.

Ricin toxin A-chain (RTA), a ribosome-inactivating protein from seeds of the castor bean plant (Ricinus communis), inactivates eukaryotic ribosomes by hydrolyzing the N-glycosidic bond of a single adenosine residue in a highly conserved loop of 28S rRNA, but does not act on prokaryotic ribosomes. We investigated the interaction of rat liver 80S ribosomes with RTA using an optical biosensor based on surface plasmon resonance (BIAcore instrument), which allows real-time recording of the interaction. RTA was coupled to the dextran gel matrix on the sensor chip surface through a single thiol group that is not involved in the enzymatic action. The interaction of rat ribosomes with RTA, which was greatly affected by the Mg(2+) concentration and ionic strength, was usually measured at 5 mM Mg(2+), 50 mM KCl, and pH 7.5. The modes of interaction of intact and RTA-depurinated rat liver ribosomes with the immobilized RTA were virtually the same, while no considerable interaction was observed for Escherichia coli ribosomes. The interaction was not influenced by the presence of 5 mM adenine, which is higher than the reported dissociation constant (1 mM) for the adenine-RTA complex. These results demonstrate that binding of the target adenine with the active site of RTA does not contribute much to the total interaction of ribosomes and RTA. Global analyses of association and dissociation data with several binding models, taking account of mass transport, allowed us to conclude that the data were unable to fit a simple 1:1 binding model, but were best described by a model including a conformational change involved in high affinity complex formation.