Surgical strategies for treatment of malignant pancreatic tumors: extended, standard or local surgery?

Tumor related pancreatic surgery has progressed significantly during recent years. Pancreatoduodenectomy (PD) with lymphadenectomy, including vascular resection, still presents the optimal surgical procedure for carcinomas in the head of pancreas. For patients with small or low-grade malignant neoplasms, as well as small pancreatic metastases located in the mid-portion of pancreas, central pancreatectomy (CP) is emerging as a safe and effective option with a low risk of developing de-novo exocrine and/or endocrine insufficiency. Total pancreatectomy (TP) is not as risky as it was years ago and can nowadays safely be performed, but its indication is limited to locally extended tumors that cannot be removed by PD or distal pancreatectomy (DP) with tumor free surgical margins. Consequently, TP has not been adopted as a routine procedure by most surgeons. On the other hand, an aggressive attitude is required in case of advanced distal pancreatic tumors, provided that safe and experienced surgery is available. Due to the development of modern instruments, laparoscopic operations became more and more successful, even in malignant pancreatic diseases. This review summarizes the recent literature on the abovementioned topics

On the Minimum Number of Multiplications Necessary for Universal Hash Functions

Abstract. Let d ≥ 1 be an integer and R1 be a finite ring whose el-ements are called block. A d-block universal hash over R1 is a vector of d multivariate polynomials in message and key block such that the maximum differential probability of the hash function is “low”. Two such single block hashes are pseudo dot-product (PDP) hash and Bernstein-Rabin-Winograd (BRW) hash which require n 2 multiplications for n mes-sage blocks. The Toeplitz construction and d independent invocations of PDP are d-block hash outputs which require d × n 2 multiplications. How-ever, here we show that at least (d − 1) + n 2 multiplications are necessary to compute a universal hash over n message blocks. We construct a d-block universal hash, called EHC, which requires the matching (d−1)+ n 2 multiplications for d ≤ 4. Hence it is optimum and our lower bound is tight when d ≤ 4. It has similar parllelizibility, key size like Toeplitz and so it can be used as a light-weight universal hash