TOWARDS A MATHEMATICAL THEORY OF ANALOGY

This paper presents a mathematical theory of analogy, which should be a basis in developing analogical reasoning by a computer. The analogy is a partial identity between two sets of facts. In order to compare several analogies, we introduce an ordering of analogies, and we define two types of optimal analogies, maximal analogies and greatest ones. We show a condition under which the greatest analogy exists, and also present a top-down procedure to find the maximal analogies

Relative value of pressures and volumes in assessing fluid responsiveness after valvular and coronary artery surgery

10% per step. Results: Global ejection fraction was tower and PAOP was higher after VS than CAS. In responding steps after VS (n = 9-14) PACP and volumes increased, white CVP and volumes increased in responding steps (n = 12-19) after CAS. Baseline PAOP was tower in responding steps after VS only. Hence, baseline PACP as well as changes in PACP and volumes were of predictive value after VS and changes in CVP and volumes after CAS, in receiver operating characteristic curves. After VS, PAOP and volume changes equally correlated to Cl changes. After CAS, only changes in CVP and volumes correlated to those in Cl. Conclusions: While volumes are equally useful in monitoring fluid responsiveness, the predictive and monitoring value of PAOP is greater after VS than after CAS. In contrast, the CVP is of similar value as volume measurements in monitoring fluid responsiveness after CAS. The different value of pressures rather than of volumes between surgery types is likely caused by systolic left ventricular dysfunction in VS. The study suggests an effect of systolic cardiac function on optimal parameters of fluid responsiveness and superiority of the pulmonary artery catheter over transpulmonary dilution, for haemodynamic monitoring of VS patients. (C) 2008 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserve

An international multicentre evaluation of treatment strategies for combined hepatocellular-cholangiocarcinoma✰

Background & Aims: Management of combined hepatocellular-cholangiocarcinoma (cHCC-CCA) is not well-defined. Therefore, we evaluated the management of cHCC-CCA using an online hospital-wide multicentre survey sent to expert centres. Methods: A survey was sent to members of the European Network for the Study of Cholangiocarcinoma (ENS-CCA) and the International Cholangiocarcinoma Research Network (ICRN), in July 2021. To capture the respondents’ contemporary decision-making process, a hypothetical case study with different tumour size and number combinations was embedded. Results: Of 155 surveys obtained, 87 (56%) were completed in full and included for analysis. Respondents represented Europe (68%), North America (20%), Asia (11%), and South America (1%) and included surgeons (46%), oncologists (29%), and hepatologists/gastroenterologists (25%). Two-thirds of the respondents included at least one new patient with cHCC-CCA per year. Liver resection was reported as the most likely treatment for a single cHCC-CCA lesion of 2.0–6.0 cm (range: 73–93%) and for two lesions, one up to 6 cm and a second well-defined lesion of 2.0 cm (range: 60–66%). Nonetheless, marked interdisciplinary differences were noted. Surgeons mainly adhered to resection if technically feasible, whereas up to half of the hepatologists/gastroenterologists and oncologists switched to alternative treatment options with increasing tumour burden. Fifty-one (59%) clinicians considered liver transplantation as an option for patients with cHCC-CCA, with the Milan criteria defining the upper limit of inclusion. Overall, well-defined cHCC-CCA treatment policies were lacking and management was most often dependent on local expertise. Conclusions: Liver resection is considered the first-line treatment of cHCC-CCA, with many clinicians supporting liver transplantation within limits. Marked interdisciplinary differences were reported, depending on local expertise. These findings stress the need for a well-defined multicentre prospective trial comparing treatments, including liver transplantation, to optimise the therapeutic management of cHCC-CCA. Impact and implications: Because the treatment of combined hepatocellular-cholangiocarcinoma (cHCC-CCA), a rare form of liver cancer, is currently not well-defined, we evaluated the contemporary treatment of this rare tumour type through an online survey sent to expert centres around the world. Based on the responses from 87 clinicians (46% surgeons, 29% oncologists, 25% hepatologists/gastroenterologists), representing four continents and 25 different countries, we found that liver resection is considered the first-line treatment of cHCC-CCA, with many clinicians supporting liver transplantation within limits. Nonetheless, marked differences in treatment decisions were reported among the different specialties (surgeon vs. oncologist vs. hepatologist/gastroenterologist), highlighting the urgent need for a standardisation of therapeutic strategies for patients with cHCC-CCA