Objective To observe the effect of canagliflozin combined with enalapril on diabetic nephropathy(DN).Methods DN patients were randomly divided into control group and treatment group.All patients in 2 groups received basic treatment of recombinant human insulin injection,and the control group was orally administered enalapril tablet 10 mg(qd).The treatment group was given orally canagliflozin tablet 100 mg(qd)on the basis of the control group.Both groups were treated for 8 weeks.Renal function,blood glucose index,serum vascular endothelial growth factor(VEGF),transforming growth factor-β(TGF-β),homocysteine(HCY)levels,clinical efficacy and incidence of adverse drug reactions were compared between 2 groups.Results There were 71 cases were included in the control group and 73 cases in the treatment group.After treatment,β2 microglobulin(β2-MG)in treatment group and control group were(0.21±0.03)and(0.28±0.04)mg·L-1;blood urea nitrogen(BUN)were(4.23±0.42)and(5.58±0.65)mmol·L-1;serum creatinine(SCr)were(89.32±8.29)and(101.25±10.18)pmol·L-1;24 h microalbumin(mAlb)were(49.38±5.06)and(58.21±6.43)mg;glycosylated hemoglobin(HbA1c)were(6.10±0.11)％and(6.45±0.16)％;2 h postprandial blood glucose levels were(6.05±0.78)and(7.68±1.82)mmol·L-1;fasting blood glucose(FBG)were(5.02±0.32)and(5.67±0.65)mmol·L-1;VEGF levels were(350.18±20.04)and(389.04±24.16)pg·mL-1;TGF-β were(148.32±16.57)and(168.24±20.02)pg·mL-1;HCY were(13.12±2.38)and(19.35±3.21)pmol·L-1,the differences were statistically significant(all P＜0.05).After treatment,the total effective rate of treatment group and control group were 83.56％(61 cases/73 cases)and 67.61％(48 cases/71 cases),the difference was statistically significant(P＜0.05).The total incidence of adverse drug reactions in treatment group and control group were 6.85％and 4.23％,with no significant difference(P＞0.05).Conclusion Canagliflozin combined with enalapril is effective in the treatment of diabetic nephropathy,which can improve renal function,regulate blood glucose metabolism,and down-regulate serum VEGF,TGF-β and HCY levels,and is safe and reliable.

AIM To rapidly screen xanthine oxidase(XOD)inhibitors from Smilax glabra Roxb.by enzyme-immobilized magnetic microspheres and LC-MS/MS,and to confirm the anti-uric acid constituents from S.glabra Roxb.METHODS The immobilized xanthine oxidase was prepared by covalent coupling with carboxyl magnetic beads as a carrier.The xanthine oxidase inhibitors in S.glabra were screened by the specific adsorption of immobilized enzyme.LC-MS/MS and standard substances were used for analysis and comparison,and the inhibitory activity and inhibition type of the screened and identified components were investigated.RESULTS The successful synthesis of immobilized xanthine oxidase was characterized by scanning electron microscopy and infrared spectroscopy.The enzyme loading was 70.50 μg/mg and the relative activity was 79.44%.Thirteen active compounds were screened from the extract of S.glabra,and eleven compounds were identified.The enzyme activity test showed that the inhibitory activites of engeletin and isoengeletin were the strongest,which was close to the positive control allopurinol.The IC50 value and inhibition type were 32.25 μg/mL,mixed inhibition,35.12 μg/mL,competitive inhibition.CONCLUSION The method is simple,rapid,accurate and suitable for directly screened active ingredients which can inhibit XOD from complex extract of traditional Chinese medicines.

The blood-brain barrier limits the brain delivery of most drugs and affects the treatment of central nervous system disorders. The transnasal drug delivery allows the drug to bypass the blood-brain barrier and reach the brain directly through pathways such as the olfactory and trigeminal nerves, thus improving the therapeutic efficacy of the drug while reducing drug degradation and avoiding hepatic first pass effect. With the rise of nanotechnology, the combination of nanoformulations with transnasal routes of administration is expected to achieve better brain targeting and treatment of brain diseases. On the basis of summarizing the characteristics of the various nose-to-brain pathways, this review summarizes the researches on novel transnasal nanopreparations such as exosomes and liquid crystals in recent years as well as new strategies to improve the efficiency of brain entry including focused ultrasound-mediated techniques. We also review the recent studies on transnasal brain entry nanopreparations in the treatment of various brain disorders and current research dilemmas, looking forward to the prospect of their future clinical applications.

Urethral stricture is characterized by the chronic formation of fibrous tissue, leading to the narrowing of the urethral lumen. Despite the availability of various endoscopic treatments, the recurrence of urethral strictures remains a common challenge. Postsurgery pharmacotherapy targeting tissue fibrosis is a promising option for reducing recurrence rates. Although drugs cannot replace surgery, they can be used as adjuvant therapies to improve outcomes. In this regard, many drugs have been proposed based on the mechanisms underlying the pathophysiology of urethral stricture. Ongoing studies have obtained substantial progress in treating urethral strictures, highlighting the potential for improved drug effectiveness through appropriate clinical delivery methods. Therefore, this review summarizes the latest researches on the mechanisms related to the pathophysiology of urethral stricture and the drugs to provide a theoretical basis and new insights for the effective use and future advancements in drug therapy for urethral stricture.

Objectives: To analyze the long-term survival of patients with localized renal cell carcinoma after partical nephrectomy. Methods: The clinicopathological records and survival follow-up data of 2 046 patients with localized renal cell carcinoma, who were treated with partial nephrectomy from August 2001 to February 2021 in the Department of Urology, Sun Yat-sen University Cancer Center, were retrospectively analyzed. There were 1 402 males and 644 females, aged (M(IQR)) 51 (19) years (range: 6 to 86 years). The primary end point of this study was cancer-specific survival. Survival curves were estimated using the Kaplan-Meier method, and the difference test was performed by Log-rank test. Univariate and multivariate Cox analysis were fitted to determine factors associated with cancer-specific survival. Results: The follow-up time was 49.2 (48.0) months (range: 1 to 229 months), with 1 974 patients surviving and 72 dying. The median cancer-specific survival time has not yet been reached. The 5- and 10-year cancer specific survival rates were 97.0% and 91.2%, respectively. The 10-year cancer-specific survival rates for stage pT1a (n=1 447), pT1b (n=523) and pT2 (n=58) were 95.3%, 81.8%, and 81.7%, respectively. The 10-year cancer-specific survival rates of patients with nuclear grade 1 (n=226), 2 (n=1 244) and 3 to 4 (n=278) were 96.6%, 89.4%, and 85.5%, respectively. There were no significant differences in 5-year cancer-specific survival rates among patients underwent open, laparoscopic, or robotic surgery (96.7% vs. 97.1% vs. 97.5%, P=0.600). Multivariate analysis showed that age≥50 years (HR=3.93, 95%CI: 1.82 to 8.47, P<0.01), T stage (T1b vs. T1a: HR=3.31, 95%CI: 1.83 to 5.99, P<0.01; T2+T3 vs. T1a: HR=2.88, 95%CI: 1.00 to 8.28, P=0.049) and nuclear grade (G3 to 4 vs. G1: HR=2.81, 95%CI: 1.01 to 7.82, P=0.048) were independent prognostic factors of localized renal cell carcinoma after partial nephrectomy. Conclusions: The long-term cancer-specific survival rates of patients with localized renal cancer after partial nephrectomy are satisfactory. The type of operation (open, laparoscopic, or robotic) has no significant effect on survival. However, patients with older age, higher nuclear grade, and higher T stage have a lower cancer-specific survival rate. Grasping surgical indications, attaching importance to preoperative evaluation, perioperative management, and postoperative follow-up, could benefit achieving satisfactory long-term survival.

AIM: To investigate the protective effect of Modified Taohong Siwu Decoction(MTSD)on hypoxia injury to retinal Müller cells rMC-1.METHODS: Retinal Müller cells rMC-1 were interfered with the MTSD drug-containing serum under hypoxia condition, and were randomly divided into control group(21%O2), hypoxia model group(1%O2), MTSD drug-containing serum low-dose(1%O2+5% medicated serum), medium-dose(1%O2+10% medicated serum)and high-dose(1%O2+15%medicated serum)groups. Cell viability was detected by CCK-8 method, and secretion of vascular endothelial growth factor(VEGF)and pigment epithelium derived factor(PEDF)was detected by ELISA. The protein expressions of p-STAT3, STAT3 and hypoxia-inducible factor-1α(HIF-1α)were detected by Western blot, and the gene expressions of VEGF, PEDF, STAT3 and HIF-1α were detected by real-time polymerase chain reaction(PCR).RESULTS: The viability of rMC-1 cells was significantly inhibited when cultured at 1%O2 for 48h compared with that of control group(P<0.05), while it was improved in both low and medium dose of MTSD groups(P<0.05). The viability of rMC-1 cells in high dose group was not improved in hypoxia condition(P>0.05). The low and medium doses of MTSD could reduce the protein expressions of VEGF in supernatant of rMC-1 cells under hypoxia condition(P<0.05), while the protein expressions of PEDF could not be increased(P>0.05). The above two dose groups down-regulated the protein levels of both p-STAT3 and HIF-1α(P<0.05), and the inhibition effect of low dose group was better than that of medium dose group(P<0.05). The medium dose of MTSD could up-regulate STAT3 protein level after hypoxia culture in rMC-1 cells(P<0.05). The low and medium doses of MTSD significantly down-regulated VEGF gene level(P<0.05)and up-regulated PEDF gene level after hypoxia culture in rMC-1 cells(P<0.05), and the function in the low dose group was superior to that in the medium dose group(P<0.05). The low dose of MTSD could down-regulate STAT3 and HIF-1α gene levels after hypoxia culture in rMC-1 cells(P<0.05).CONCLUSION: Probably by inhibiting the STAT3/HIF-1α pathway, the drug-containing serum of MDST down-regulated the expression of VEGF protein and gene in hypoxia-induced retinal Müller cells, rMC-1, up-regulated the gene expression of PEDF, and alleviated the hypoxia injury to the cells.

Objective: To establish a nomogram prognostic model for predicting the 5-, 10-, and 15-year overall survival (OS) of non-metastatic renal cell carcinoma patients managed with radical nephrectomy (RN), compare the modelled results with the results of pure pathologic staging, the Karakiewicz nomogram and the Mayo Clinic Stage, Size, Grade, and Necrosis (SSIGN) score commonly used in foreign countries, and stratify the patients into different prognostic risk subgroups. Methods: A total of 1 246 non-metastatic renal cell carcinoma patients managed with RN in Sun Yat-sen University Cancer Center (SYSUCC) from 1999 to 2020 were retrospectively analyzed. Multivariate Cox regression analysis was used to screen the variables that influence the prognosis for nomogram establishment, and the bootstrap random sampling was used for internal validation. The time-receiver operating characteristic curve (ROC), the calibration curve and the clinical decision curve analysis (DCA) were applied to evaluate the nomogram. The prediction efficacy of the nomogram and that of the pure pathologic staging, the Karakiewicz nomogram and the SSIGN score was compared through the area under the curve (AUC). Finally, patients were stratified into different risk subgroups according to our nomogram scores. Results: A total of 1 246 patients managed with RN were enrolled in this study. Multivariate Cox regression analysis showed that age, smoking history, pathological nuclear grade, sarcomatoid differentiation, tumor necrosis and pathological T and N stages were independent prognostic factors for RN patients (all P<0.05). A nomogram model named SYSUCC based on these factors was built to predict the 5-, 10-, and 15-year survival rate of the participating patients. In the bootstrap random sampling with 1 000 iterations, all these factors occurred for more than 800 times as independent predictors. The Harrell's concordance index (C-index) of SYSUCC was higher compared with pure pathological staging [0.770 (95% CI: 0.716-0.823) vs 0.674 (95% CI: 0.621-0.728)]. The calibration curve showed that the survival rate as predicted by the SYSUCC model simulated the actual rate, while the clinical DCA showed that the SYSUCC nomogram has a benefit in certain probability ranges. In the ROC analysis that included 857 patients with detailed pathological nuclear stages, the nomogram had a larger AUC (5-/10-year AUC: 0.823/0.804) and better discriminating ability than pure pathological staging (5-/10-year AUC: 0.701/0.658), Karakiewicz nomogram (5-/10-year AUC: 0.772/0.734) and SSIGN score (5-/10-year AUC: 0.792/0.750) in predicting the 5-/10-year OS of RN patients (all P<0.05). In addition, the AUC of the SYSUCC nomogram for predicting the 15-year OS (0.820) was larger than that of the SSIGN score (0.709), and there was no statistical difference (P<0.05) between the SYSUCC nomogram, pure pathological staging (0.773) and the Karakiewicz nomogram (0.826). The calibration curve was close to the standard curve, which indicated that the model has good predictive performance. Finally, patients were stratified into low-, intermediate-, and high-risk subgroups (738, 379 and 129, respectively) according to the SYSUCC nomogram scores, among whom patients in intermediate- and high-risk subgroups had a worse OS than patients in the low-risk subgroup (intermediate-risk group vs. low-risk group: HR=4.33, 95% CI: 3.22-5.81, P<0.001; high-risk group vs low-risk group: HR=11.95, 95% CI: 8.29-17.24, P<0.001), and the high-risk subgroup had a worse OS than the intermediate-risk group (HR=2.63, 95% CI: 1.88-3.68, P<0.001). Conclusions: Age, smoking history, pathological nuclear grade, sarcomatoid differentiation, tumor necrosis and pathological stage were independent prognostic factors for non-metastasis renal cell carcinoma patients after RN. The SYSUCC nomogram based on these independent prognostic factors can better predict the 5-, 10-, and 15-year OS than pure pathological staging, the Karakiewicz nomogram and the SSIGN score of patients after RN. In addition, the SYSUCC nomogram has good discrimination, agreement, risk stratification and clinical application potential.
Humans ; Nomograms ; Retrospective Studies ; Carcinoma, Renal Cell/pathology* ; Prognosis ; Risk Factors ; Nephrectomy ; Kidney Neoplasms/pathology* ; Necrosis

Objective: To establish a nomogram prognostic model for predicting the 5-, 10-, and 15-year overall survival (OS) of non-metastatic renal cell carcinoma patients managed with radical nephrectomy (RN), compare the modelled results with the results of pure pathologic staging, the Karakiewicz nomogram and the Mayo Clinic Stage, Size, Grade, and Necrosis (SSIGN) score commonly used in foreign countries, and stratify the patients into different prognostic risk subgroups. Methods: A total of 1 246 non-metastatic renal cell carcinoma patients managed with RN in Sun Yat-sen University Cancer Center (SYSUCC) from 1999 to 2020 were retrospectively analyzed. Multivariate Cox regression analysis was used to screen the variables that influence the prognosis for nomogram establishment, and the bootstrap random sampling was used for internal validation. The time-receiver operating characteristic curve (ROC), the calibration curve and the clinical decision curve analysis (DCA) were applied to evaluate the nomogram. The prediction efficacy of the nomogram and that of the pure pathologic staging, the Karakiewicz nomogram and the SSIGN score was compared through the area under the curve (AUC). Finally, patients were stratified into different risk subgroups according to our nomogram scores. Results: A total of 1 246 patients managed with RN were enrolled in this study. Multivariate Cox regression analysis showed that age, smoking history, pathological nuclear grade, sarcomatoid differentiation, tumor necrosis and pathological T and N stages were independent prognostic factors for RN patients (all P<0.05). A nomogram model named SYSUCC based on these factors was built to predict the 5-, 10-, and 15-year survival rate of the participating patients. In the bootstrap random sampling with 1 000 iterations, all these factors occurred for more than 800 times as independent predictors. The Harrell's concordance index (C-index) of SYSUCC was higher compared with pure pathological staging [0.770 (95% CI: 0.716-0.823) vs 0.674 (95% CI: 0.621-0.728)]. The calibration curve showed that the survival rate as predicted by the SYSUCC model simulated the actual rate, while the clinical DCA showed that the SYSUCC nomogram has a benefit in certain probability ranges. In the ROC analysis that included 857 patients with detailed pathological nuclear stages, the nomogram had a larger AUC (5-/10-year AUC: 0.823/0.804) and better discriminating ability than pure pathological staging (5-/10-year AUC: 0.701/0.658), Karakiewicz nomogram (5-/10-year AUC: 0.772/0.734) and SSIGN score (5-/10-year AUC: 0.792/0.750) in predicting the 5-/10-year OS of RN patients (all P<0.05). In addition, the AUC of the SYSUCC nomogram for predicting the 15-year OS (0.820) was larger than that of the SSIGN score (0.709), and there was no statistical difference (P<0.05) between the SYSUCC nomogram, pure pathological staging (0.773) and the Karakiewicz nomogram (0.826). The calibration curve was close to the standard curve, which indicated that the model has good predictive performance. Finally, patients were stratified into low-, intermediate-, and high-risk subgroups (738, 379 and 129, respectively) according to the SYSUCC nomogram scores, among whom patients in intermediate- and high-risk subgroups had a worse OS than patients in the low-risk subgroup (intermediate-risk group vs. low-risk group: HR=4.33, 95% CI: 3.22-5.81, P<0.001; high-risk group vs low-risk group: HR=11.95, 95% CI: 8.29-17.24, P<0.001), and the high-risk subgroup had a worse OS than the intermediate-risk group (HR=2.63, 95% CI: 1.88-3.68, P<0.001). Conclusions: Age, smoking history, pathological nuclear grade, sarcomatoid differentiation, tumor necrosis and pathological stage were independent prognostic factors for non-metastasis renal cell carcinoma patients after RN. The SYSUCC nomogram based on these independent prognostic factors can better predict the 5-, 10-, and 15-year OS than pure pathological staging, the Karakiewicz nomogram and the SSIGN score of patients after RN. In addition, the SYSUCC nomogram has good discrimination, agreement, risk stratification and clinical application potential.
Humans ; Nomograms ; Retrospective Studies ; Carcinoma, Renal Cell/pathology* ; Prognosis ; Risk Factors ; Nephrectomy ; Kidney Neoplasms/pathology* ; Necrosis

Objective: To report the long-term survival of renal cell carcinoma (RCC) patients treated with radical nephrectomy in Sun Yat-sen University Cancer Center. Methods: We retrospectively analyzed the clinical, pathological and follow-up records of 1 367 non-metastatic RCC patients treated with radical nephrectomy from 1999 to 2020 in this center. The primary endpoint of this study was overall survival rate. Survival curves were estimated using the Kaplan-Meier method, and group differences were compared through Log-rank test. Univariate and multivariate Cox analysis were fit to determine the clinical and pathological features associated with overall survival rate. Results: A total of 1 367 patients treated with radical nephrectomy with complete follow-up data were included in the study. The median follow-up time was 52.6 months, and 1 100 patients survived and 267 died, with the median time to overall survival not yet reached. The 5-year and 10-year overall survival rates were 82.8% and 74.9%, respectively. The 5-year and 10-year overall survival rates of Leibovich low-risk patients were 93.3% and 88.2%, respectively; of Leibovich intermediate-risk patients were 82.2% and 72.3%, respectively; and of Leibovich high-risk patients were 50.5% and 30.2%, respectively. There were significant differences in the long-term survival among the three groups (P<0.001). The 10-year overall survival rates for patients with pT1, pT2, pT3 and pT4 RCC were 83.2%, 73.6%, 55.0% and 31.4%, respectively. There were significant differences among pT1, pT2, pT3 and pT4 patients(P<0.001). The 5-year and 10-year overall survival rates of patients with lymph node metastasis were 48.5% and 35.6%, respectively, and those of patients without lymph node metastasis were 85.1% and 77.5%, respectively. There was significant difference in the long-term survival between patients with lymph node metastasis and without lymph node metastasis. The 10-year overall survival rate was 96.2% for nuclear Grade 1, 81.6% for nuclear Grade 2, 60.5% for nuclear Grade 3, and 43.4% for nuclear Grade 4 patients. The difference was statistically significant. There was no significant difference in the long-term survival between patients with localized renal cancer (pT1-2N0M0) who underwent open surgery and minimally invasive surgery (10-year overall survival rate 80.5% vs 85.6%, P=0.160). Multivariate Cox analysis showed that age≥55 years (HR=2.11, 95% CI: 1.50-2.96, P<0.001), T stage(T3+ T4 vs T1a: HR=2.37, 95% CI: 1.26-4.46, P=0.008), local lymph node metastasis (HR=3.04, 95%CI: 1.81-5.09, P<0.001), nuclear grade (G3-G4 vs G1: HR=4.21, 95%CI: 1.51-11.75, P=0.006), tumor necrosis (HR=1.66, 95% CI: 1.17-2.37, P=0.005), sarcomatoid differentiation (HR=2.39, 95% CI: 1.31-4.35, P=0.005) and BMI≥24kg/m(2) (HR=0.56, 95%CI: 0.39-0.80, P=0.001) were independent factors affecting long-term survival after radical nephrectomy. Conclusions: The long-term survival of radical nephrectomy in patients with renal cell carcinoma is satisfactory. Advanced age, higher pathological stage and grade, tumor necrosis and sarcomatoid differentiation were the main adverse factors affecting the prognosis of patients. Higher body mass index was a protective factor for the prognosis of patients.
Humans ; Middle Aged ; Carcinoma, Renal Cell/secondary* ; Lymphatic Metastasis ; Retrospective Studies ; Neoplasm Staging ; Kidney Neoplasms/pathology* ; Prognosis ; Nephrectomy ; Survival Analysis ; Necrosis/surgery* ; Survival Rate

Objective: To report the long-term survival of renal cell carcinoma (RCC) patients treated with radical nephrectomy in Sun Yat-sen University Cancer Center. Methods: We retrospectively analyzed the clinical, pathological and follow-up records of 1 367 non-metastatic RCC patients treated with radical nephrectomy from 1999 to 2020 in this center. The primary endpoint of this study was overall survival rate. Survival curves were estimated using the Kaplan-Meier method, and group differences were compared through Log-rank test. Univariate and multivariate Cox analysis were fit to determine the clinical and pathological features associated with overall survival rate. Results: A total of 1 367 patients treated with radical nephrectomy with complete follow-up data were included in the study. The median follow-up time was 52.6 months, and 1 100 patients survived and 267 died, with the median time to overall survival not yet reached. The 5-year and 10-year overall survival rates were 82.8% and 74.9%, respectively. The 5-year and 10-year overall survival rates of Leibovich low-risk patients were 93.3% and 88.2%, respectively; of Leibovich intermediate-risk patients were 82.2% and 72.3%, respectively; and of Leibovich high-risk patients were 50.5% and 30.2%, respectively. There were significant differences in the long-term survival among the three groups (P<0.001). The 10-year overall survival rates for patients with pT1, pT2, pT3 and pT4 RCC were 83.2%, 73.6%, 55.0% and 31.4%, respectively. There were significant differences among pT1, pT2, pT3 and pT4 patients(P<0.001). The 5-year and 10-year overall survival rates of patients with lymph node metastasis were 48.5% and 35.6%, respectively, and those of patients without lymph node metastasis were 85.1% and 77.5%, respectively. There was significant difference in the long-term survival between patients with lymph node metastasis and without lymph node metastasis. The 10-year overall survival rate was 96.2% for nuclear Grade 1, 81.6% for nuclear Grade 2, 60.5% for nuclear Grade 3, and 43.4% for nuclear Grade 4 patients. The difference was statistically significant. There was no significant difference in the long-term survival between patients with localized renal cancer (pT1-2N0M0) who underwent open surgery and minimally invasive surgery (10-year overall survival rate 80.5% vs 85.6%, P=0.160). Multivariate Cox analysis showed that age≥55 years (HR=2.11, 95% CI: 1.50-2.96, P<0.001), T stage(T3+ T4 vs T1a: HR=2.37, 95% CI: 1.26-4.46, P=0.008), local lymph node metastasis (HR=3.04, 95%CI: 1.81-5.09, P<0.001), nuclear grade (G3-G4 vs G1: HR=4.21, 95%CI: 1.51-11.75, P=0.006), tumor necrosis (HR=1.66, 95% CI: 1.17-2.37, P=0.005), sarcomatoid differentiation (HR=2.39, 95% CI: 1.31-4.35, P=0.005) and BMI≥24kg/m(2) (HR=0.56, 95%CI: 0.39-0.80, P=0.001) were independent factors affecting long-term survival after radical nephrectomy. Conclusions: The long-term survival of radical nephrectomy in patients with renal cell carcinoma is satisfactory. Advanced age, higher pathological stage and grade, tumor necrosis and sarcomatoid differentiation were the main adverse factors affecting the prognosis of patients. Higher body mass index was a protective factor for the prognosis of patients.
Humans ; Middle Aged ; Carcinoma, Renal Cell/secondary* ; Lymphatic Metastasis ; Retrospective Studies ; Neoplasm Staging ; Kidney Neoplasms/pathology* ; Prognosis ; Nephrectomy ; Survival Analysis ; Necrosis/surgery* ; Survival Rate