Which differences do elderly patients present in single-stage treatment for cholecysto-choledocholithiasis?

Patients with symptomatic gallstones present common bile duct stones in approximately 10% of cases. It is possible to resolve both gallbladder and bile duct stones with a single procedure. The aim of this study is to determine the effectiveness of a single stage procedure for gallbladder and bile duct stones in the elderly patients and to expose the differences between the various techniques. From January 2008 to December 2013, we treated 1540 patients with gallbladder stones. In 152 cases, we also found bile duct stones. 150 of these were treated in a single stage procedure. We divided our patients into 2 groups: Group A was younger than 65 (104 patients); Group B was 65 or older (46 patients). We retrospectively compared sex, ASA score, conversion rate, success rate, post-operative complications, hospital stay, and treatment method. We had no intra-operative mortality. 1 patient in Group B, heart condition (ASA 4), died with multiple organ failure (MOF) 10 days after his operation. ASA score: 3.5 ± 0.5 in A vs 2 ± 0.9 in B (P 0.001), post-operative complications 6% in A vs 18.1% in B (P 0.0325) and hospital stay 4.1 ± 2.3 in A vs 9.5 ± 5.5 in B (P 0.0001) were significantly higher in Group B. No differences were found in term of success rate: 94% in A vs 90% in B (P 0.4944). The procedure used to obtain the clearance of the bile duct showed a different success rate across the two groups: for the patients under 65 years old, trans-cystic clearance (TC-CBDE) was successful in 90% of cases, and only 51% for those older than 65, where we had to recall 49% for laparo-endoscopic rendez-vous (RV-IOERC) (P 0.0014). In conclusion, single stage treatment is safe and effective also to elderly patients. The methods used in patients being younger than 65 years old is what appeared to be significantly different.

Absorbent Markov chains as a model for the study of the evolution of proteins.

The formalism of absorbent Markov chains, previously developed by Kemeny & Snell (1960) is used as a model for the study of the evolution of proteins. Within the limits of statistical analysis used, the amino acid substitution frequencies of McLachlan (1972) are explained by the numerical values derived from the model used. In addition, the amino acid composition of proteins is partially explained and the relative mutability of amino acids receives a new interpretation in the light of the above mentioned stochastic model. The results show that some basic aspect of protein evolution can be predicted by a stochastic model and therefore a significant component of protein evolution is driven by a random element.