Thrcc new trapdoor one-way functions are proposed that are based on elliptic curves over thc ring 2, . The first class of functions is a naive construction, d i i c h can be used only in a digital signature scheme, and not in a public-key cryptosystem. The second, preferred class of function, does not suffer from this problem and can be used for the samc applications as the RSA trapdoor one-way function, including zero-knowledge identification protocols. The third class of functions has similar properties to the Rabin trapdoor one-way functions. Although the security of these proposed schemes is Imsetl on the difficulty of factoring n, like the RSA and Rabin schemes, these schemes seem to be more secure than those schemes from the viewpoint of attacks without factoring such as low multiplier attacks. The new schemes are somewhat less efficient than the RSA atid Rabin schemes. ' N T T Laboratories

Early postoperative evaluation was prospectively performed in 35 gastric cancer patients after pylorus-preserving gastrectomy (PPG) between 1989 and 1991, comparing the results with those of 29 patients who underwent conventional distal gastrectomy (CDG). Surgical stress, including the duration of operation (149.0 +/- 4.3 minutes) and the total volume of bleeding at operation (97.0 +/- 11.2 g), was significantly less in the PPG patients. Early postoperative complications were seen in 31% after PPG and in 35% after CDG. The most frequent complication in PPG patients was remnant gastric stasis (23%). Endoscopy showed redness or erosion (or both) of the gastric remnant in 17% after PPG and in 81% after CDG. Bile regurgitation was demonstrated in 11% after PPG and in 62% after CDG. In PPG patients, the pyloric ring opened and closed during the examination. Gastric pH was 4.2 +/- 0.4 in PPG patients but was significantly lower in CDG patients. The resting gallbladder area, examined by ultrasonography, demonstrated no changes after PPG but was significantly enlarged after CDG (from 11.3 +/- 1.2 cm2 to 15.8 +/- 1.5 cm2 at 2 weeks). The percentage of the original resting gallbladder area at 20 minutes after injection of cerulein increased slightly in PPG patients but recovered thereafter, whereas in CDG patients it increased significantly (from 39.4 +/- 8.3% to 66.7 +/- 9.1% at 2 weeks). No gallstone formation was detected throughout the observation period after PPG, whereas after CDG it was detected in two patients at 1 year.(ABSTRACT TRUNCATED AT 250 WORDS)

Wilson disease is a genetic disorder of copper metabolism characterized by the toxic accumulation of copper in the liver. The ATP7B gene, which encodes a copper transporting P-type ATPase, is defective in patients with Wilson disease. To investigate the function of ATP7B, wild type or mutated ATP7B cDNA was introduced into a yeast strain lacking the CCC2 gene (v vccc2), the yeast homologue of ATP7B. Wild type and the H1069Q mutant could rescue v vccc2, however, the N1270S mutant could not, reflecting phenotypic variability of Wilson disease. In addition, the mutant containing only the sixth copper binding domain could rescue v vccc2, indicating its functional importance.z 1998 Federation of European Biochemical Societies.

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Abstract. The basic operation in elliptic crypt.osystaems is t,he computation of a multiple rl.P of a point P on the elliptic curve modulo n . We propose a fast and systematic method of reducing t.he number of operations over elliptic curves. T h e proposed method is based on pre-computation to generate an adequate a.cldition-subtraction chain for multiplier the d .