Can Erectile Dysfunction Severity Predict Major Adverse Cardiovascular Events in Men Undergoing Dialysis? A Prospective Cohort Study

PURPOSE

To evaluate the impact of severe erectile dysfunction (ED) on future major adverse cardiovascular events (MACE) in men on dialysis.

MATERIALS AND METHODS

This prospective cohort study included 71 men on dialysis. ED was assessed using the Sexual Health Inventory for Men (SHIM). Men were divided into the mild/moderate ED (SHIM score ≥8) and severe ED (SHIM score ≤7) groups. The primary endpoint was MACE-free survival. MACE was a composite of myocardial infarction, cardiovascular death, and stroke. The secondary endpoints were cardiac event-free survival and overall survival (OS). Moreover, the predictive abilities of severe ED for 5-year MACE, 5-year cardiac events, and 5-year overall mortality were evaluated.

RESULTS

The median age and follow-up period of the included men were 64 years and 58 months, respectively. The median SHIM score was 4.0; all had a degree of ED, and 64.7% had severe ED. In the background-adjusted multivariable analyses, severe ED was not significantly associated with shorter MACE-free survival (hazard ratio [HR], 1.890; 95% confidence interval [CI], 0.533-6.706; p=0.324), cardiac event-free survival (HR, 2.081; 95% CI, 0.687-6.304; p=0.195), and OS (HR, 0.817; 95% CI, 0.358-1.863; p=0.630). Severe ED did not significantly improve the predictive abilities for 5-year MACE, 5-year cardiac events, and 5-year overall mortality (p=0.110, p=0.101, and p=0.740, respectively).

CONCLUSIONS

ED severity was not associated with shorter MACE-free survival, cardiac event-free survival, or OS, and ED severity could not improve the predictive abilities for these outcomes in men undergoing dialysis.

Association between Aortic Calcification Burden and the Severity of Erectile Dysfunction in Men Undergoing Dialysis: A Cross-Sectional Study

PURPOSE

Accelerated atherosclerosis is a major complication in patients with end-stage renal disease and it plays an important role in the pathogenesis of erectile dysfunction (ED). However, the association between aortic calcification burden and the severity of ED remains unclear. The aim of the present study was to investigate this association in men undergoing dialysis.

MATERIALS AND METHODS

This cross-sectional study included 71 men undergoing peritoneal dialysis and/or hemodialysis between July 2016 and May 2018 at Mutsu General Hospital. ED was assessed with the Sexual Health Inventory for Men (SHIM). Patients were divided into the mild/moderate (SHIM score ≥8) and severe ED groups (SHIM score ≤7). Aortic calcification index (ACI) was examined as a clinical indicator of abdominal aortic calcification. Multivariable logistic regression analysis was performed to identify the significant factors associated with severe ED.

RESULTS

The median age of the study participants was 64 years; all had ED, with 64.8% having severe ED. In the multivariable analyses, a slight association was observed between ankle-brachial index and severe ED (odds ratio [OR], 0.058; p=0.072), whereas ACI was significantly associated with severe ED (OR, 1.022; p=0.022).

CONCLUSIONS

Aortic calcification burden was independently associated with severe ED.

Combination of Muscle Quantity and Quality Is Useful to Assess the Necessity of Surveillance after a 5-Year Cancer-Free Period in Patients Who Undergo Radical Cystectomy: A Multi-Institutional Retrospective Study

BACKGROUND

Although continuous surveillance after a 5-year cancer-free period in patients with bladder cancer (BC) who undergo radical cystectomy (RC) is recommended, optimal candidates for continuous surveillance remain unclear. Sarcopenia is associated with unfavorable prognosis in various malignancies. We aimed to investigate the impact of low muscle quantity and quality (defined as severe sarcopenia) on prognosis after a 5-year cancer-free period in patients who underwent RC.

METHODS

We conducted a multi-institutional retrospective study assessing 166 patients who underwent RC and had five years or more of follow-up periods after a 5-year cancer-free period. Muscle quantity and quality were evaluated using the psoas muscle index (PMI) and intramuscular adipose tissue content (IMAC) using computed tomography images five years after RC. Patients with lower PMI and higher IMAC values than the cut-off values were diagnosed with severe sarcopenia. Univariable analyses were performed to assess the impact of severe sarcopenia on recurrence, adjusting for the competing risk of death using the Fine-Gray competing risk regression model. Moreover, the impact of severe sarcopenia on non-cancer-specific survival was evaluated using univariable and multivariable analyses.

RESULTS

The median age and follow-up period after the 5-year cancer-free period were 73 years and 94 months, respectively. Of 166 patients, 32 were diagnosed with severe sarcopenia. The 10-year RFS rate was 94.4%. In the Fine-Gray competing risk regression model, severe sarcopenia did not show a significant higher probability of recurrence, with an adjusted subdistribution hazard ratio of 0.525 (p = 0.540), whereas severe sarcopenia was significantly associated with non-cancer-specific survival (hazard ratio 1.909, p = 0.047). These results indicate that patients with severe sarcopenia might not need continuous surveillance after a 5-year cancer-free period, considering the high non-cancer-specific mortality.

Impact of neoadjuvant chemotherapy–induced acute kidney injury on oncological outcomes in patients who underwent radical cystectomy: A multicenter retrospective study

573

Background: Neoadjuvant chemotherapy (NAC)-induced acute kidney injury (AKI) is a frequent complication in patients with muscle-invasive bladder cancer (MIBC). Although previous studies have reported that AKI during cancer treatment was associated with poor oncological outcomes in several cancers, the impact of NAC-induced AKI on oncological outcomes in patients with MIBC remains unclear. Methods: This retrospective study included 398 patients who received 2-4 cycles of NAC followed by radical cystectomy (RC). AKI was defined according to the KDIGO criteria. Patients were divided into two groups: patients who developed AKI during NAC (AKI group) and patients who did not (non-AKI group). Multivariable Cox-proportional hazards regression analyses were performed to evaluate the impact of NAC-induced AKI on recurrence-free survival (RFS), cancer-specific survival (CSS), and overall survival (OS). Results: The median age and follow-up period were 69 years and 62 months, respectively. Of the 398 patients, 66 (17%) developed AKI during NAC. The rates of <ypT2 and downstage in the AKI group were significantly lower than those in the non-AKI group (38% vs. 53%, P = 0.023; 53% vs. 69%, P = 0.013; respectively). After adjustment for age, performance status, cisplatin-based regimen, tumor grade, pathological T stage, pathological lymph-node involvement, and positive surgical margin, AKI was associated with shorter RFS (hazard ratio [HR] 1.619, P = 0.043), CSS (HR 1.727, P = 0.049), and OS (HR 1.848, P = 0.008). Conclusions: NAC-induced AKI was associated with reduced effects of NAC and poor oncological outcomes in patients who underwent RC.

Association of oxidative stress with erectile dysfunction in community-dwelling men and men on dialysis

OBJECTIVES

To investigate the association between oxidative stress and erectile dysfunction (ED) in community-dwelling men and men on dialysis.

METHODS

This cross-sectional study included 398 community-dwelling men and 42 men on dialysis. Oxidative stress was assessed using 8-hydroxy-2'-deoxyguanosine (8-OHdG). Univariable and multivariable logistic regression analyses were performed to evaluate the association between oxidative stress and ED.

RESULTS

Spearman's rank correlation test showed no significant correlation between urine 8-OHdG levels and the 5-Item International Index of Erectile Function scores in community-dwelling men (ρ = -0.005, p = 0.917) and between plasma 8-OHdG levels and the Sexual Health Inventory for Men scores in men on dialysis (ρ = 0.166, p = 0.295). In community-dwelling men, univariable and multivariable analyses revealed that urine 8-OHdG level was not significantly associated with ED (odds ratio [OR]: 1.005, 95% confidence interval [CI]: 0.884-1.144, p = 0.934; OR: 0.930, 95% CI: 0.798-1.084, p = 0.353; respectively). In men on dialysis, univariable analyses revealed that plasma 8-OHdG level was not significantly associated with severe ED (OR: 0.967, 95% CI: 0.876-1.066, p = 0.498).

CONCLUSIONS

Oxidative stress was not significantly associated with ED prevalence and severity in community-dwelling men and men on dialysis.

Associations of impaired grip strength and gait function with the severity of erectile dysfunction in men undergoing dialysis: a cross-sectional study

OBJECTIVE

To investigate the associations of impaired muscle strength and gait function with the severity of erectile dysfunction (ED) in men undergoing dialysis.

METHODS

This cross-sectional study included 63 men undergoing dialysis. ED was assessed with the Sexual Health Inventory for Men (SHIM). Patients were divided into the mild/moderate (SHIM score ≥8) and severe ED groups (SHIM score ≤7). Correlations between variables were analyzed using Spearman's rank correlation coefficient. Multivariable logistic regression analyses were performed to evaluate the impact of impaired grip strength and gait function on the severity of ED.

RESULTS

The median age of the study participants was 62 years; all had ED, with 67% having severe ED. Spearman's rank correlation test demonstrated significant negative and positive correlations between gait function and SHIM score (ρ = -0.257, p = 0.042) and between grip strength and SHIM score (ρ = 0.305, p = 0.015), respectively. In the multivariable analyses, impaired grip strength was significantly associated with severe ED (odds ratio [OR]: 4.965, p = 0.017), whereas gait function was not (OR: 3.147, p = 0.064).

CONCLUSION

Impaired muscle strength was significantly associated with severe ED, whereas impaired gait function had a marginal effect on this erectile condition.

Relationships of low-grade systemic inflammation and nutritional status with erectile dysfunction severity in men on dialysis

BACKGROUND

Low-grade systemic inflammation and malnutrition are frequently observed in patients on dialysis and contribute to the development of endothelial dysfunction, however, the role of these conditions in erectile dysfunction (ED) severity remains to be elucidated.

OBJECTIVES

To investigate the relationships of low-grade systemic inflammation and nutritional status with ED severity in men on dialysis.

MATERIALS AND METHODS

The present study included 71 men on dialysis. The Sexual Health Inventory for Men (SHIM) was used to assess ED. Men were classified as the mild/moderate (SHIM score ≥ 8) and severe ED (SHIM score ≤ 7) groups. C-reactive protein/albumin ratio (CAR) and Geriatric Nutritional Risk Index (GNRI) were used to evaluate low-grade systemic inflammation and nutritional status, respectively. We performed multivariate analysis to assess the relationships of CAR and GNRI with severe ED.

RESULTS

The median age of the included men was 64 years old. All men had any degree of ED with 65% having severe ED. In the univariate analyses, a significant association was observed between elevated CAR (≥ 0.09) and severe ED (odds ratio [OR]: 4.038, P = 0.025), whereas no significant association was observed between lower GNRI (< 92) and severe ED (OR: 2.357, P = 0.109). In the multivariate analysis, an association between elevated CAR and severe ED was still significant (OR: 5.985, P = 0.010).

DISCUSSION AND CONCLUSION

Low-grade systemic inflammation was significantly associated with ED severity, whereas lower GNRI was not. These results may be helpful for further research to identify the optimal treatment for men suffering from severe ED. This article is protected by copyright. All rights reserved.

Single immediate instillation of chemotherapy is associated with decreased recurrence and progression in patients with high-risk non-muscle-invasive bladder cancer who receive adjuvant induction bacillus Calmette-Guérin therapy

OBJECTIVES

To investigate whether a single intravesical instillation of chemotherapy is associated with improved oncological outcomes in patients with high-risk non-muscle-invasive bladder cancer who receive adjuvant induction bacillus Calmette-Guérin therapy.

METHODS

This multi-institutional retrospective study included 205 patients with high-risk non-muscle-invasive bladder cancer who received adjuvant induction bacillus Calmette-Guérin therapy. Patients were divided into two groups: those who received the combined therapy of a single instillation of chemotherapy plus subsequent adjuvant induction bacillus Calmette-Guérin therapy (combined therapy group), and those who received adjuvant induction bacillus Calmette-Guérin therapy alone (bacillus Calmette-Guérin monotherapy group). Multivariable analyses using the inverse probability of treatment weighting method and Fine-Gray competing risk regression models were performed to evaluate the impact of a single instillation of chemotherapy on intravesical recurrence-free survival and muscle-invasive bladder cancer-free survival.

RESULTS

Among the 205 patients, 130 (63%) and 75 (37%) were classified as the combined therapy and bacillus Calmette-Guérin monotherapy groups, respectively. Multivariable analyses using the inverse probability of treatment weighting method showed that a single instillation of chemotherapy was significantly associated with longer intravesical recurrence-free survival (hazard ratio 0.279; P < 0.001) and muscle-invasive bladder cancer-free survival (hazard ratio 0.078; P < 0.001). Fine-Gray competing risk regression model revealed that a single instillation of chemotherapy was associated with a significantly lower probability of intravesical recurrence and muscle-invasive bladder cancer progression, with an adjusted subdistribution hazard ratio of 0.477 (P = 0.008) and 0.261 (P = 0.043), respectively.

CONCLUSION

A single intravesical instillation of chemotherapy may be a potential treatment option in patients with high-risk non-muscle-invasive bladder cancer who receive adjuvant induction bacillus Calmette-Guérin therapy.

Characteristics of α2,3-sialyl N-glycosylated PSA as a biomarker for clinically significant prostate cancer in men with elevated PSA level

BACKGROUND

The presence of glycosylated isoforms of prostate-specific antigen (PSA) in prostate cancer (PC) cells is a potential marker of their aggressiveness. We characterized the origin of α2,3-sialylated prostate-specific antigen (S23PSA) by tissue-based sialylation-related gene expression and studied the performance of S23PSA density (S23PSAD) alone and in combination with multiparametric magnetic resonance imaging (MRI) for the detection of clinically significant prostate cancer in men with elevated PSA.

METHODS

Tissue-based quantification of S23PSA and sialyltransferase and sialidase gene expression was evaluated in 71 radical prostatectomy specimens. The diagnostic performance of S23PSAD was studied in 1099 men retrospectively enrolled in a multicenter systematic biopsy (SBx) cohort. We correlated the S23PSAD with Prostate Imaging Reporting and Data System (PI-RADS) scores in 98 men prospectively enrolled in a single-center MRI-targeted biopsy (MRI-TBx) cohort. The primary outcome was the PC-diagnostic performance of the S23PSAD, the secondary outcome was the avoidable biopsy rate of S23PSAD combined with DRE and total PSA (tPSA), and with or without PI-RADS.

RESULTS

S23PSA was significantly higher in Gleason pattern 4 and 5 compared with benign prostate tissue. In the retrospective cohort, the performance of S23PSAD for detecting PC was superior to tPSA or PSA density (PSAD) (AUC: 0.7758 vs. 0.6360 and 0.7509, respectively). In the prospective cohort, S23PSAD was superior to tPSA, PSAD, and PI-RADS (AUC: 0.7725 vs. 0.5901, 0.7439 and 0.7305, respectively), and S23PSAD + PI-RADS + DRE + tPSA was superior to DRE + tPSA+PI-RADS with avoidance rate of MRI-TBx (13% vs. 1%) at 30% risk threshold.

CONCLUSIONS

The diagnostic performance of S23PSAD was superior to conventional strategies but comparable to mpMRI.

Relationship of frailty with treatment modality selection in patients with muscle-invasive bladder cancer (FRART-BC study)

Background

We aimed to investigate the association of frailty with treatment selection in patients with muscle-invasive bladder cancer (MIBC) as frailty is one of the key factors for modality selection.

Methods

We retrospectively evaluated frailty in 169 patients with MIBC from January 2014 to September 2020 using the Fried phenotype, modified frailty index, and frailty discriminant score. The primary purpose was comparing the frailty between the patients who underwent radical cystectomy (RC) with those who had trimodal therapy (TMT) for bladder preservation. Secondary purposes were comparing the frailty between the groups and the effect of TMT on overall survival adjusting the frailty by multivariate Cox proportional hazards analysis using inverse probability of treatment weighting (IPTW)-adjusted model.

Results

Of 169 patients, 96 and 73 were classified into the RC and the TMT groups, respectively. The median age of the TMT group was significantly higher than that of the RC group (80 vs. 69 years). Frailty levels and prevalence in the Fried phenotype, modified frailty index, and frailty discriminant score were significantly higher in the TMT group than those in the RC group. Logistic regression analysis showed that frailty was significantly associated with the TMT selection. Overall survival was significantly shorter in the TMT group by the IPTW-adjusted Cox regression analysis (hazard ratio 2.48, P=0.043).

Conclusions

Frailty was significantly different between the RC and TMT in patients with MIBC and might be one of the key factors for treatment selection.

Association between the baseline frailty and quality of life in patients with prostate cancer (FRAQ-PC study)

BACKGROUND

The association between baseline frailty and health-related quality of life (HRQOL) in patients with prostate cancer (PC) remains unknown.

METHODS

We retrospectively evaluated the association of pretreatment frailty with HRQOL in 409 patients with PC from February 2017 to April 2020. Frailty and HRQOL were evaluated using the geriatric 8 (G8) screening tool and QLQ-C30 questionnaire, respectively. The primary objective was comparison of G8 and QOL scores between the localized diseases (M0 group) and metastatic castration-sensitive PC (mCSPC group). Secondary objectives were to study the association of G8 and QOL scores in each group and effect of frailty (G8 ≤ 14) on worse QOL.

RESULTS

The median age of patients was 70 years. There were 369 (surgery: 196, radiotherapy: 156, androgen deprivation therapy alone: 17) patients in the M0 and 40 patients in the mCSPC groups. There was a significant difference between the M0 and mCSPC groups in the G8 score (14.5 vs. 12.5), functioning QOL (94 vs. 87), global QOL (75 vs. 58), and 100-symptom QOL (94 vs. 85) scores. G8 scores were significantly associated with functioning, global, and 100-symptom QOL scores in both M0 and mCSPC groups. The multivariable logistic regression analyses showed that frailty (G8 ≤ 14) was significantly associated with worse global QOL, functioning QOL, and 100-symptom QOL scores.

CONCLUSION

The baseline frailty and HRQOL were significantly different between the localized and metastatic disease. The baseline frailty was significantly associated with worse HRQOL in patients with PC.

Impact of symptomatic recurrence on oncological outcomes in patients with primary high-risk non-muscle-invasive bladder cancer

OBJECTIVES

To evaluate the impact of symptomatic recurrence on oncological outcomes in patients with primary high-risk non-muscle invasive bladder cancer (NMIBC) who underwent transurethral resection of bladder tumor (TURBT).

MATERIALS AND METHODS

We retrospectively evaluated 428 patients with primary high-risk NMIBC who underwent TURBT from November 1993 to April 2019. Of the 428 patients, 140 had experienced recurrence at any site and were divided into 2 groups: patients who had experienced recurrence detected by the surveillance (asymptomatic group) and patients who had experienced recurrence detected by a symptom-driven investigation (symptomatic group). Background-adjusted multivariable analyses with the inverse probability of treatment weighting method were performed to evaluate the impact of symptomatic recurrence on cancer-specific survival and overall survival after first recurrence in patients who had experienced recurrence. Moreover, multivariable analysis was performed to identify predictive factors of symptomatic recurrence in the entire cohort.

RESULTS

Median age and follow-up periods were 72 (interquartile range [IQR] 64-79) years and 55 (IQR 29-96) months, respectively. Of the 140 patients who experienced recurrence, 106 (76%) were diagnosed by the surveillance (asymptomatic group) and 34 (24%) were diagnosed by a symptom-driven investigation (symptomatic group). In the background-adjusted multivariable analyses with the inverse probability of treatment weighting model, symptomatic recurrence was significantly associated with shorter cancer-specific survival along with shorter overall survival after first recurrence. In the multivariable analysis, only tumor grade was selected as a significant predictive factor of symptomatic recurrence after TURBT.

CONCLUSIONS

Symptomatic recurrence was significantly associated with poor oncological outcomes in patients with primary high-risk NMIBC. Patients with grade 3 tumors may require more intensive surveillance after TURBT.

The effect of frailty on the quality of life and lower urinary symptoms following robot-assisted radical prostatectomy: A longitudinal analysis (FRARP-QL Study)

OBJECTIVES

We aimed to evaluate the effect of frailty on health-related quality-of-life (HRQOL) and lower urinary symptoms (LUTS) following robot-assisted radical prostatectomy (RARP) in patients with prostate cancer (CaP).

MATERIALS AND METHODS

We longitudinally evaluated geriatric 8 (G8), HRQOL, and LUTS for 12 months in 118 patients with RARP from January 2017 to April 2020. Patients were divided into frail (G8 ≤14) and nonfrail (G8 >14) groups. We compared the effect of frailty on HRQOL and LUTS between the frail and nonfrail groups before and 12 months after RARP.

RESULTS

The median age of patients was 68 years. The number of patients in the frail and nonfrail groups were 41 and 77, respectively. No significant difference in patients' background was observed between the groups, except for the presence of cardiovascular disease (22% vs. 7.8%, P = 0.041). There was no significant difference in HRQOLs and LUTS between the groups at baseline. Similarly, HRQOLs, LUTS, and pad-free continence rates were not significantly different between the groups at 12 months after RARP. In the nonfrail group, LUTS at 12 months following RARP significantly improved compared to those at the baseline, but it did not significantly improve in the frail group. Multivariable logistic regression analysis demonstrated that frailty was not significantly associated with LUTS worsening.

CONCLUSIONS

Frailty was not significantly associated with the worsening of HRQOL, LUTS, and pad-free continence rates in patients treated with RARP.

Impact of chronic kidney disease on oncological outcomes in patients with high-risk non-muscle-invasive bladder cancer who underwent adjuvant bacillus Calmette-Guérin therapy

OBJECTIVES

To investigate the impact of chronic kidney disease (CKD) on oncological outcomes in patients with high-risk non-muscle invasive bladder cancer (NMIBC) who underwent adjuvant induction bacillus Calmette-Guérin (BCG) therapy after transurethral resection of bladder tumor (TURBT).

MATERIALS AND METHODS

We conducted a multi-institutional retrospective study assessing 209 patients with high-risk NMIBC who underwent TURBT and subsequent adjuvant induction BCG therapy from December 1998 to April 2019. Patients were divided into 2 groups: those with preoperative estimated glomerular filtration rate (eGFR) ≥ 60 ml/min/1.73 m² (non-CKD group), and those with eGFR < 60 ml/min/1.73 m² (CKD group). Primary endpoints were intravesical recurrence-free survival (RFS) and muscle-invasive bladder cancer (MIBC)-free survival. Background-adjusted multivariate analyses with the inverse probability of treatment weighting (IPTW) method using the propensity score were performed to evaluate the impact of CKD on intravesical RFS, MIBC-free survival, metastasis-free survival, cancer-specific survival, and overall survival. Moreover, multivariable analyses were performed to assess the impact of CKD on intravesical recurrence and MIBC progression, adjusting for the competing risk of death using the Fine-Gray competing risk regression model.

RESULTS

Median age and follow-up period after TURBT were 72 years and 45 months, respectively. Of 209 patients, 71 (34%) were diagnosed with CKD before TURBT. Background-adjusted multivariate analyses with the IPTW method indicated that CKD was significantly associated with shorter intravesical RFS, MIBC-free survival, metastasis-free survival, cancer-specific survival, and overall survival. In the Fine-Gray competing risk regression model, CKD showed significantly higher probabilities of intravesical recurrence and MIBC progression, with an adjusted subdistribution hazard ratio of 1.886 (95% confidence interval 1.069-3.330, P = 0.028) and 3.740 (95% confidence interval 1.060-13.20, P = 0.040), respectively.

CONCLUSIONS

CKD presents a risk factor of poor oncological outcomes in patients with high-risk NMIBC who underwent adjuvant induction BCG therapy after TURBT.

Effect of frailty and comorbidity on surgical contraindication in patients with localized prostate cancer (FRART-PC Study)

OBJECTIVES

To determine how frailty and comorbidities affect surgical contraindication in patients with localized prostate cancer (CaP).

MATERIALS AND METHODS

We evaluated the effects of frailty in 479 patients with localized CaP who were treated with robot-assisted radical prostatectomy (RARP), or radiotherapy (RT) eligible for surgery (RT-nonfrail), or those with RT ineligible for surgery due to frailty or comorbidity (RT-frail) from February 2017 to April 2020. We retrospectively compared the geriatric 8 screening (G8) scores between patients with surgical indications (RARP and RT-nonfrail groups) and those with surgical contraindications (RT-frail group). The effect of G8 score in the RT-frail groups was investigated using multivariate logistic regression analysis. We developed and validated a nomogram for surgical contraindication in patients with localized CaP.

RESULTS

The median age of patients was 70 years. There were 256, 60, and 163 patients in the RARP, RT-nonfrail, and RT-frail, respectively. The G8 score in the RARP and RT-nonfrail groups was significantly higher than in the RT-frail group (15 vs. 14, respectively, P < 0.001). Age, comorbidities (cerebrocardiovascular disease or chronic respiratory disease), and G8 score were significantly associated with the RT-frail group. The nomogram showed that the area under the curve was 0.872 and 0.923 in the training and validation sets, respectively. The cutoff for surgical contraindication was >39.5%.

CONCLUSIONS

The G8 score and comorbidities have a significant effect on surgical contraindication in patients with localized CaP.

Intraoperative upper urinary tract cytology examination is a risk factor of upper urinary tract recurrence in patients with non-muscle-invasive bladder cancer

OBJECTIVES

To evaluate the impact of intraoperative upper urinary tract (UUT) cytology examination in patients with non-muscle-invasive bladder cancer (NMIBC) who had undergone transurethral resection of bladder tumor (TURBT).

MATERIALS AND METHODS

We retrospectively evaluated 414 patients with NMIBC who had undergone transurethral resection of bladder tumor between November 1993 and April 2019. Patients with simultaneous UUT urothelial carcinoma (UC) detected via computed tomography were excluded. Patients were divided into 2 groups: those who had undergone intraoperative bilateral UUT cytology examination via retrograde catheterization (study group) and those who had not (control group). We evaluated the utility of intraoperative UUT cytology examination, comparing surgical outcomes and perioperative complications between the 2 groups. In addition, we evaluated the impact of UUT cytology examination on UUT recurrence using background-adjusted multivariate analysis.

RESULTS

We obtained 292 UUT urine samples from 146 patients with a median age of 72 years. Of 292 UUT urine samples, 11 (3.7%) were positive and 3 were finally diagnosed as UUT UC. Positive predictive value and false positive rate were 18% and 3.1%, respectively. Operative time for the study group was significantly longer than for the control group. Rate of perioperative complications were not significantly different between the 2 groups. However, in background-adjusted multivariate analysis, intraoperative UUT cytology examination was associated with significantly shorter UUT recurrence-free survival.

CONCLUSION

Intraoperative UUT cytology examination may not be recommended as a result of low positive predictive value due to contamination and UUT recurrence risk in patients with NMIBC.

Geriatric 8 screening of frailty in patients with prostate cancer

OBJECTIVES

To evaluate the association between the score of the Geriatric 8 screening tool and treatment by disease stages in patients with prostate cancer.

METHODS

Between January 2017 and June 2019, we prospectively evaluated the Geriatric 8 in 540 prostate cancer patients who were treated with robot-assisted radical prostatectomy, radiotherapy, androgen deprivation therapy alone and standard of care for metastatic hormone-naïve prostate cancer or castration-resistant prostate cancer. The primary purpose was the association between frailty (Geriatric 8 ≤14) and robot-assisted radical prostatectomy, radiotherapy, androgen deprivation therapy alone, and metastatic diseases. Secondary purposes included a comparison of the Geriatric 8 scores among the disease status and the influence of Geriatric 8 score on overall survival.

RESULTS

The median age was 75 years. Geriatric 8 scores ≤14 were seen in 36% of robot-assisted radical prostatectomy (n = 78/214), 57% of radiotherapy (n = 119/209), 91% of androgen deprivation therapy alone (n = 19/21) and 70% of metastatic diseases (n = 67/96). The median Geriatric 8 score in patients treated with robot-assisted radical prostatectomy, radiotherapy, androgen deprivation therapy alone and metastatic diseases was 15.0, 14.0, 12.0 and 12.8, respectively. The median Geriatric 8 score was significantly higher in the metastatic disease than that in localized disease (14.5 vs 12.8, respectively). Robot-assisted radical prostatectomy patients had a significantly higher Geriatric 8 score than radiotherapy patients, with the cut-off value of <14.5. The overall survival was significantly different between Geriatric 8 scores ≤13 and >13 in metastatic hormone-naïve prostate cancer patients, and between Geriatric 8 scores ≤12 and >12 in castration-resistant prostate cancer patients.

CONCLUSION

The Geriatric 8 score is significantly associated with treatment by disease stages in patients with prostate cancer.

Frailty is significantly associated with the type of urinary diversion in patients with muscle-invasive bladder cancer

OBJECTIVES

To investigate the effect of frailty on the type of urinary diversion after radical cystectomy in patients with muscle-invasive bladder cancer.

METHODS

Between January 2014 and January 2020, we prospectively evaluated frailty in 88 patients with localized muscle-invasive bladder cancer, who had received radical cystectomy and urinary diversion. The selection of the type of urinary diversion was determined by the operating surgeon based on performance status, comorbidities, tumor status and the patient's preference. The frailty evaluation included the Fried phenotype criteria, the modified frailty index and the frailty discriminant score. We investigated the association between frailty and type of urinary diversion, the effect of frailty on postoperative complications and the effect of frailty on overall survival.

RESULTS

The median age of the selected participants was 68 years. The number of patients with an orthotopic neobladder and any postoperative complications was 54 (61%) and 46 (52%), respectively. Of the frailty assessment tools that were used, Fried phenotype criteria and frailty discriminant score were significantly associated with the selection of non-orthotopic neobladder urinary diversion. Occurrences of postoperative complications in participants were significantly associated with modified frailty index, but not with Fried phenotype criteria and frailty discriminant score. Multivariate Cox regression analysis showed that a higher frailty discriminant score was significantly associated with poor overall survival, whereas higher Fried phenotype criteria and modified frailty index were not.

CONCLUSION

Frailty is significantly associated with the type of urinary diversion, and it should be considered for the selection of urinary diversion in muscle-invasive bladder cancer patients undergoing radical cystectomy.

Frailty is a predictor of moderate to severe pain after robot‐assisted laparoscopic prostatectomy: A case‐control study (FRAP study)

Objective

To investigate the association of pain with frailty in patients with localized prostate cancer (PC) who underwent robot‐assisted laparoscopic radical prostatectomy (RARP).

Materials and Methods

Between January 2017 and June 2019, we prospectively evaluated the geriatric 8 (G8) score, simplified frailty index (sFI), and numerical rating scale (NRS) of 154 patients with localized PC who underwent RARP at our institution. NRS was measured on preoperative day 0, postoperative days 1, 2, 3, and at discharge. Moderate to severe pain was defined as NRS ≥ 5, whereas frailty was defined as G8 ≤ 14. The primary objectives of this study were to investigate the effects of moderate to severe pain (NRS ≥ 5) on frailty, postoperative complications, and the use of analgesics after RARP. Our secondary objectives were the effect of frailty on postoperative complications and the use of analgesics.

Results

The median age of participants was 69 years. Of 154 patients, 37 (24%) and 61 (40%) were classified to have NRS ≥ 5 and G8 ≤ 14, respectively. Patients with NRS > 5 presented significantly association with G8 < 14, whereas they did not show the association with sFI, complication, or analgesics. Multivariate logistic regression analysis showed that G8 ≤ 14 was significantly associated with NRS ≥ 5. Frailty was not significantly associated with postoperative complications and analgesics.

Conclusions

Frailty was significantly associated with moderate to severe pain after RARP, and might be a potential predictor of postoperative pain. Frail patients require individual care to avoid painful experiences.

Impact of substratification on predicting oncological outcomes in patients with primary high-risk non-muscle-invasive bladder cancer who underwent transurethral resection of bladder tumor

OBJECTIVES

To validate the substratification of high-risk in the European Association of Urology (EAU) guidelines and to develop the simplified substratification to improve usefulness and predictive accuracy on oncological outcomes in patients with primary high-risk nonmuscle-invasive bladder cancer (NMIBC) who underwent transurethral resection of bladder tumor (TURBT).

MATERIALS AND METHODS

We retrospectively evaluated 428 patients with primary high-risk NMIBC who underwent TURBT from November 1993 to April 2019. First, the efficacy of the EAU highest-risk on intravesical recurrence-free survival (RFS) and muscle-invasive bladder cancer (MIBC)-free survival was evaluated with univariate analyses. Second, we developed our simplified substratification based on multivariate analysis for intravesical RFS (lower- and higher-risk). We compared predictive accuracy on oncological outcomes using the receiver operating characteristic curve between the EAU and the simplified substratifications.

RESULTS

Median age and median follow-up periods were 72 years and 51 months, respectively. The EAU highest-risk was not associated with shorter intravesical RFS and MIBC-free survival (P = 0.054 and P = 0.350, respectively). In multivariate analysis, tumor size, grade 3, and chronic kidney disease were significantly associated with shorter intravesical RFS, and we developed the simplified substratification including those 3 factors. Of 428 patients, 89 (21%) were substratified into the simplified higher-risk. The predictive accuracy of the simplified substratification on intravesical recurrence, MIBC and metastasis progression, and cancer-specific mortality was significantly superior to the EAU substratification.

CONCLUSION

Our simplified substratification might contribute to improving predictive accuracy on intravesical recurrence, MIBC and metastasis progression, and cancer-specific mortality in patients with primary high-risk NMIBC who underwent TURBT.

Safety and efficacy of intensive instillation of low-dose pirarubicin vs. bacillus Calmette-Guérin in patients with high-risk non-muscle-invasive bladder cancer

OBJECTIVES

To evaluate the safety and efficacy of intensive intravesical instillation of low-dose pirarubicin (THP) for 6 times vs. bacillus Calmette-Guérin (BCG) without maintenance therapy after transurethral resection of bladder tumor (TURBT) in patients with primary high-risk non-muscle-invasive bladder cancer (NMIBC).

MATERIALS AND METHODS

We retrospectively evaluated 370 patients with primary high-risk NMIBC who underwent TURBT from November 1993 to April 2019. The patients were divided into 2 groups: patients treated with intravesical instillation of BCG without maintenance therapy (BCG group) and intensive intravesical instillation of low-dose (20 mg) THP for 6 times within 10 days after TURBT (THP group). Safety was assessed using the Common Terminology Criteria for Adverse Events version 5.0. Background-adjusted multivariate analyses were performed to evaluate the effect of intensive intravesical instillation of low-dose THP on oncological outcomes, including intravesical recurrence-free survival (RFS), upper urinary tract RFS, muscle-invasive bladder cancer-free survival, metastasis-free survival, cancer-specific survival, and overall survival.

RESULTS

Of the 370 patients with primary high-risk NMIBC, 180 (49%) and 190 (51%) were stratified into the BCG and THP groups, respectively. The incidence rate of adverse events of any grade in the BCG group was significantly higher than that in the THP group (P < 0.001). In the background-adjusted multivariate analyses, no significant differences were observed in oncological outcomes between the BCG and THP groups.

CONCLUSIONS

Intensive intravesical instillation of low-dose THP for 6 times may be one of the treatment options in view of safety and efficacy after TURBT in patients with primary high-risk NMIBC.

Preoperative chronic kidney disease predicts poor prognosis in patients with primary non-muscle-invasive bladder cancer who underwent transurethral resection of bladder tumor

OBJECTIVES

To evaluate the impact of preoperative chronic kidney disease (CKD) on the prognosis of patients with primary non-muscle-invasive bladder cancer (NMIBC) who underwent transurethral resection of bladder tumor (TURBT).

MATERIALS AND METHODS

We retrospectively evaluated 434 patients with primary NMIBC who underwent TURBT from November 1993 to April 2019. The patients were divided into 2 groups: patients with preoperative estimated glomerular filtration rate ≥60 ml/min/1.73 m² (non-CKD group) and <60 ml/min/1.73 m² (CKD group). Background-adjusted multivariate analyses were performed to evaluate the effect of preoperative CKD on oncological outcomes, including intravesical recurrence-free survival, muscle-invasive bladder cancer-free survival, upper urinary tract (UUT) recurrence-free survival, metastasis-free survival, cancer-specific survival, and overall survival. We evaluated predictive accuracy of CKD on prognosis using the receiver operating characteristic curve and compared between risk factors in the European Organization for Research and Treatment of Cancer scoring system and CKD plus those risk factors.

RESULTS

The median age and median follow-up period were 72 years and 51 months, respectively. Of 434 patients, 141 (32%) were diagnosed with CKD before TURBT. In background-adjusted multivariate analyses, CKD was an independent risk factor for those oncological outcomes, except for UUT recurrence. The predictive accuracy of CKD plus risk factors in the European Organization for Research and Treatment of Cancer scoring system on oncological outcomes was significantly improved compared with those risk factors alone, except for UUT recurrence.

CONCLUSION

Preoperative CKD was a risk factor and might improve predictive accuracy on poor prognosis in patients with primary NMIBC who underwent TURBT.

Safety and Feasibility of Radiation Therapy to the Primary Tumor in Patients With Metastatic Castration-resistant Prostate Cancer

INTRODUCTION

The objective of this study was to evaluate the safety and feasibility of radiation therapy (RT) to the primary tumor in patients with metastatic castration-resistant prostate cancer (mCRPC).

PATIENTS AND METHODS

This retrospective study included 105 patients with mCRPC who were treated between April 2004 and May 2019. We divided the patients into 2 groups: patients treated with RT to the primary tumor after they developed CRPC (RT group) and without (non-RT group). The primary purpose was safety assessed using the Common Terminology Criteria for Adverse Events. The secondary purpose included prostate-specific antigen (PSA) response, cancer-specific survival (CSS), and overall survival (OS). Background-adjusted multivariate analyses, with the inverse probability of treatment weighting (IPTW) method, were performed to evaluate impact of RT on CSS and OS.

RESULTS

The median age at CRPC diagnosis was 75 years, and the median follow-up period after CRPC diagnosis was 21 months. The adverse events rates related to RT in any grade and grade ≥ 3 were 55% and 23%, respectively. Nine (29%) patients achieved ≥ 30% PSA decline with RT. In multivariate analyses with the IPTW method, the CSS and OS in the RT group were significantly longer than those in the non-RT group. In subgroup analyses with the IPTW method, RT was significantly associated with improved OS in patients aged ≥ 75 years and patients with initial PSA ≥ 500 ng/mL, cT4, Gleason score ≥ 8, and high-volume metastatic burden.

CONCLUSIONS

RT to the primary tumor is safe and feasible, and it has potential benefits on oncologic outcomes in patients with mCRPC.

Relationship between Geriatric 8 screening score and treatment selection in patients with prostate cancer

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Background: This study aimed to evaluate the geriatric 8 (G8) screening tool for detecting frailty in patients with prostate cancer. Methods: Between January 2017 and June 2019, we prospectively evaluated the G8 in 540 prostate cancer patients, 444 with localized stage M0 and 96 with metastatic stage M1 disease. The primary endpoint was the comparison of G8 scores in patients treated with robot-assisted radical prostatectomy (RARP), radiotherapy, androgen deprivation therapy alone (ADT-alone) for localized disease, and standard care for the M1 disease. Secondary endpoint included the cutoff estimation of G8 score and the influence of G8 on prognosis. Results: The median age was 75 years. G8 scores ≤14 indicating frailty were seen in 36% of RARP (n = 214), 57% of RT (n = 209), 91% of ADT-alone (n = 21), and 70% of M1 disease (n=96). The median G8 score in M0 patients was significantly higher than that in M1 patients (14.5 vs 12.8, respectively). The median G8 score in patients treated with RARP, RT and ADT-alone was 15, 14, and 12, respectively. The patients with RARP had significantly higher G8 score than that of RT or ADT-alone. The optimal G8 cutoff score for patients with M0 and M1 disease was 13.0 (AUC: 0.681). The overall survival was significantly shorter in patients with G8 <13 than that of ≥13. Conclusions: The G8 score of patients with localized and metastatic PC was significantly different. Frailty was significantly associated with treatment selection and prognosis in patients with PC.

Risk-stratified surveillance protocol improves cost-effectiveness after radical nephroureterectomy in patients with upper tract urothelial carcinoma

Objectives

To develop a surveillance protocol with improved cost-effectiveness after radical nephroureterectomy (RNU), as the cost-effectiveness of oncological surveillance after RNU remains unclear.

Results

Of 426 patients, 109 (26%) and 113 (27%) experienced visceral and intravesical recurrences, respectively. The pathology-based protocol found significant differences in recurrence-free survival in the visceral recurrence but not in the intravesical recurrence. The medical costs per visceral recurrence detected were high, especially in normal-risk (≤ pT2N0, LVI-, SM-) patients. We developed a risk score associated with visceral recurrence using Cox regression analysis. The risk score-based protocol was significantly more cost-effective than the pathology-based protocol. Estimated cost differences reached $747,929 per recurrence detected, a suggested 55% reduction.

Materials and Methods

We retrospectively evaluated 426 patients with RNU for upper tract urothelial carcinoma (UTUC) without distant metastasis at 4 hospitals. Patients with routine oncological follow-up were stratified into normal-, high- and very high-risk groups according to a pathology-based protocol utilizing pathological stage, lymphovascular invasion (LVI) and surgical margin (SM). Cost-effectiveness of the pathology-based protocol was evaluated, and a risk score-based protocol was developed to optimize cost-effectiveness. Risk scores were calculated by summing up risk factors independently associated with recurrence-free survival. Patients were stratified by low-, intermediate- and high-risk score. Estimated cost per recurrence detected by pathology-based and risk score-based protocols was compared.

Conclusions

A risk score-stratified surveillance protocol has the potential to reduce over investigation during follow-up, making surveillance more cost-effective.

The relationship between poor nutritional status and progression of aortic calcification in patients on maintenance hemodialysis

Background

Although aortic calcification has a significant negative impact on prognosis in patients on hemodialysis (HD), risk factors for aortic calcification progression remain unclear. The aim of this study was to investigate the relationship between malnutrition and aortic calcification progression in patients on HD.

Methods

Between April 2015 and October 2016, we treated 232 patients on HD. Of those, we retrospectively evaluated data from 184 patients who had had regular blood tests and computed tomography (CT) scans. The abdominal aortic calcification index (ACI) was quantitatively measured by abdominal CT. Nutritional status was evaluated using the Geriatric Nutritional Risk Index (GNRI). A normalized treatment ratio of functional urea clearance was evaluated by Kt/V. The difference in ACI values between 2015 and 2016 was evaluated as a ΔACI, and patients were stratified into two groups according to ΔACI value: high (≥75th percentile, ΔACI-high group) and low (<75th percentile, ΔACI-low group). Variables such as age, sex, comorbidities, dialysis vintage, serum data, and GNRI were compared between ΔACI-high and ΔACI-low patients. Factors independently associated with a higher ΔACI progression (ΔACI ≥75th percentile) were determined using multivariate logistic analysis.

Results

Median values of ACIs in 2015 and 2016 were 40.8 and 44.6%, respectively. Of 184 patients, 125 (68%) patients experienced ACI progression for 1 year. The median ΔACI and 75th percentile of ΔACI were 2.5% and 5.8%, respectively. The number of patients in the ΔACI-low and ΔACI-high groups were 128 (70%) and 56 (30%), respectively. There were significant differences in sex, presence of diabetic nephropathy, HD vintage, serum albumin, serum phosphate, C-reactive protein, intact parathyroid hormone, Kt/V, and GNRI. Multivariate logistic regression analysis revealed that independent factors associated with a higher ΔACI progression were male sex, serum phosphate levels, HD vintage, and GNRI of < 90.

Conclusions

Our results suggest that poor nutritional status is an independent risk factor for the progression of aortic calcification. Nutrition management may have the potential to improve progression of aortic calcification in patients on HD.

Trial registration

UMIN Clinical Trials Registry UMIN000028050.

Detecting asymptomatic recurrence after radical nephroureterectomy contributes to better prognosis in patients with upper urinary tract urothelial carcinoma

Background

The prognostic benefit of regular follow-up to detect asymptomatic recurrence after radical nephroureterectomy (RNU) remains unclear. We aimed to assess whether regular follow-up to detect asymptomatic recurrence after RNU improves patient survival.

Materials and Methods

We retrospectively analysed 415 patients who underwent RNU for upper tract urothelial carcinoma at four hospitals between January 1995 and February 2017. All patients had regular follow-up examinations after RNU including urine cytology, blood biochemical tests, and computed tomography. We investigated the first site and date of tumor recurrence. Overall survivals of patients who developed recurrence, stratified by mode of recurrence (asymptomatic vs. symptomatic group), were estimated using the Kaplan-Meier method with the log-rank test. Cox proportional hazards regression analysis was performed using inverse probability of treatment weighting (IPTW) to evaluate the impact of the mode of recurrence on survival.

Results

Of the 415 patients, 108 (26%) experienced disease recurrences after RNU. Of these, 62 (57%) were asymptomatic and 46 (43%) were symptomatic at the time of diagnosis. The most common recurrence site and symptom were lymph nodes and pain, respectively. Overall survival after RNU and time from recurrence to death in the asymptomatic group were significantly longer than that in the symptomatic group. Multivariate Cox regression analysis showed that symptomatic recurrence was an independent risk factor for overall survival after RNU and survival from recurrence to death.

Conclusions

Routine oncological follow-up for detection of asymptomatic recurrence contributes to a better prognosis after RNU.

Preoperative chronic kidney disease predicts poor oncological outcomes after radical nephroureterectomy in patients with upper urinary tract urothelial carcinoma

Objective

To evaluate the impact of preoperative chronic kidney disease (CKD) on oncological outcomes in patients with upper tract urothelial carcinoma who underwent radical nephroureterectomy.

Methods

A total of 426 patients who underwent radical nephroureterectomy at five medical centers between February 1995 and February 2017 were retrospectively examined. Oncological outcomes, including intravesical recurrence-free, visceral recurrence-free, cancer-specific, and overall survival rates (intravesical RFS, visceral RFS, CSS, and OS, respectively) stratified by preoperative CKD status (CKD vs. non-CKD) were investigated. Cox proportional hazards regression analysis was performed using inverse probability of treatment weighting (IPTW) to evaluate the impact of preoperative CKD on prognosis and a prognostic factor-based risk stratification nomogram was developed.

Results

Of the 426 patients, 250 (59%) were diagnosed with CKD before radical nephroureterectomy. Before the background adjustment, intravesical RFS, visceral RFS, CSS, and OS after radical nephroureterectomy were significantly shorter in the CKD group than in the non-CKD group. Background-adjusted IPTW analysis demonstrated that preoperative CKD was significantly associated with poor visceral RFS, CSS, and OS after radical nephroureterectomy. Intravesical RFS was not significantly associated with preoperative CKD. The nomogram for predicting 5-year visceral RFS and CSS probability demonstrated a significant correlation with actual visceral RFS and CSS (c-index = 0.85 and 0.83, respectively).

Conclusions

Upper tract urothelial carcinoma patients with preoperative CKD had a significantly lower survival probability than those without CKD.

Further studies on physicochemical properties of mitochondrial membranes during the formation process of megamitochondria in the rat liver by hydrazine

Physicochemical properties of lipids extracted from hepatic mitochondria of rats fed with 1% hydrazine diet for 3 days (3H-mitochondria) and 7 days (7H-mitochondria) were studied using differential scanning calorimetry and the fluorescence polarization measurements. Results obtained from lipids extracted from 3H-mitochondria were as follows: (1) Thermotropic phase transition temperatures (Tm) were elevated with a distinct increase in transition enthalpy (delta H) compared to those of the control due to increases in relative amounts of phosphatidylethanolamine (PE) and phosphatidylserine (PS) in phospholipid species. (2) Tm in lipids and phospholipids extracted from 3H-mitochondria was elevated with decreases in delta H after the addition of Ca2+, whereas delta H of the control was increased after the addition of Ca2+. (3) Phosphatidylcholine (PC) liposomes containing PE or PS at concentrations corresponding to PE/PC or PS/PC ratio in 3H-mitochondria showed elevations of transition temperatures with decreases in delta H values after the addition of Ca2+, whereas those containing PE or PS ratio at concentrations corresponding to PE/PC or PS/PC in the control mitochondria showed increases in delta H values after the addition of Ca2+. (4) There were essentially no changes in membrane fluidity between lipids extracted from 3H-mitochondria and those extracted from the control mitochondria. Addition of Ca2+ to lipids extracted from 3H-mitochondria, however, caused elevation of membrane fluidity while those extracted from the control mitochondria showed no changes in membrane fluidity after the addition of Ca2+. (5) Increases in the ratio of unsaturated fatty acids to saturated fatty acids (U/S ratio) in phospholipids extracted from 3H-mitochondria were found to be mainly due to those in PS. These data may suggest that hydrazine modifies the membrane of mitochondria favorable for the membrane fusion via enhanced acidic phospholipid-Ca2+ interactions.

Effects of alkyl alcohols and related chemicals on rat liver structure and function. III. Physiochemical properties of ethanol-, propanol- and butanol- treated rat liver mitochondrial membranes

The physicochemical properties of mitochondria in liver tissue obtained from rats given 32% ethanol, 32% propanol or 6.9% butanol in drinking water for up to 3 months were investigated using differential scanning calorimetry and fluorescence polarization measurements. The results obtained were as follows: 1) Phospholipids extracted from mitochondria showed increases in the relative amounts of phosphatidylcholine, phosphatidylinositol and phosphatidylserine, and a decrease in the relative amount of phosphatidylethanolamine. An increase in the unsaturated/saturated fatty acid ratio of phospholipids was also observed. 2) Elevation of the thermotropic lipid phase transition temperature with a decrease in the enthalpy value (delta H) was revealed by differential scanning calorimetry. 3) The elevation of the lipid phase transition temperature was detected also by fluorescence polarization measurements using 1,6-diphenyl-1,3,5-hexatriene (DPH) as a probe. Elevation of mitochondrial membrane fluidity was found in some of the experimental animals, but most showed no changes in comparison with the control. A possible role of membrane fusion in the mechanism of formation of ethanol-, propanol- and butanol-induced hepatic megamitochondria is discussed on the basis of these results.

Changes in physicochemical properties of mitochondrial membranes during the formation process of megamitochondria induced by hydrazine

Changes in some biochemical and physico-chemical properties of rat liver mitochondrial membranes during the formation process of megamitochondria induced by hydrazine were analyzed. Hepatic mitochondria obtained from rats placed on a 1% hydrazine diet for 3 days became slightly enlarged and sometimes elongated, while they became gigantic after 7 days of hydrazine intoxication. Changes were observed in mitochondria from rats treated with hydrazine for 3 days. Total amounts of phospholipids extracted from mitochondria and submitochondrial fractions were increased. Among phospholipid species, relative amounts of acidic phospholipids were increased. Contents of Ca2+ in mitochondria were increased. Differential scanning calorimetric analysis of mitochondria, especially that of the outer membrane fraction, showed that the thermotropic lipid phase transition temperatures were elevated accompanying the broadening of thermograms and the increase in transition enthalpy. Contents of water in mitochondria were increased significantly with the ratio of freezable water to unfreezable water unchanged. Among the changes observed was that the total amount of phospholipids (except for that of the outer membrane fraction) and the contents of water and Ca2+ nearly returned to normal in megamitochondria after 7 days of hydrazine intoxication. Relative amounts of phospholipids and thermotropic lipid phase transition temperatures of megamitochondria did not return to normal levels and yet changes were smaller than those obtained from 3 days of hydrazine intoxication. The fluidity of mitochondrial membranes was not affected by hydrazine treatment. These data would suggest that hydrazine-induced megamitochondrial formation is not due simply to the swelling of mitochondria, but might be due to the fusion of adjacent mitochondria by Ca2+-acidic phospholipid interactions, and once megamitochondria are formed the mitochondrial membranes are stabilized.