Objective To find out more extrema simultaneously including global optimum and multiple local optima existed in multi-modal functions. Methods Germinal center is the generator and selector of high-affinity B cells, a multicellular group's artificial immune algorithm was proposed based on the germinal center reaction mechanism of natural immune systems. Main steps of the algorithm were given, including hyper-mutation, selection, memory, similarity suppression and recruitment of B cells and the convergence of it was proved. Results The algorithm has been tested to optimize various multi-modal functions, and the simulation results show that the artificial immune algorithm proposed here can find multiple extremum of these functions with lower computational cost. Conclusion The algorithm is valid and can converge on the satisfactory solution set D with probability 1 and approach to global solution and many local optimal solutions existed.

【Objective】 To explore the clinical features, treatment and prognosis of paraganglioma of the urinary bladder (PUB). 【Methods】 The clinical data of 41 PUB patients treated at our hospital during Sep.2012 and Sep.2022 were collected. The clinical features, surgical records, pathological reports and follow-up records were retrospectively analyzed. Patients’ survival was estimated with Kaplan-Meier estimator. The differences among groups were compared with Log-rank test. 【Results】 Among the 41 patients, 20 were male and 21 were female, with a median age of 52 years. All patients were treated with surgery, including transurethral resection of bladder tumor (TURBT) in 16 cases, partial cystectomy (PC) in 23 cases, and radical cystectomy (RC) in 2 cases. All patients were followed up for 4.0 to 125.0 months, with a median of 59.0 months. Local recurrence occurred in 5 patients, and distant metastasis occurred in 5 patients. Survival analysis showed that the 5-year overall survival (OS) rate and 5-year relapse-free survival (RFS) rate were 95.7% and 84.8%, respectively. Further analysis showed statistically significant differences in OS and RFS among groups with different maximum tumor diameters, growth patterns, and Ki-67 expressions (P<0.05). For patients with a maximum tumor diameter ≤2.8 cm, there was no significant difference in OS and RFS among different surgical groups. 【Conclusion】 PUB is rare, and a definitive diagnosis is based on pathology. In addition, the main treatment is surgery and the prognosis is good.