The repeatability of cognitive performance: a meta-analysis.

Behavioural and cognitive processes play important roles in mediating an individual's interactions with its environment. Yet, while there is a vast literature on repeatable individual differences in behaviour, relatively little is known about the repeatability of cognitive performance. To further our understanding of the evolution of cognition, we gathered 44 studies on individual performance of 25 species across six animal classes and used meta-analysis to assess whether cognitive performance is repeatable. We compared repeatability (R) in performance (1) on the same task presented at different times (temporal repeatability), and (2) on different tasks that measured the same putative cognitive ability (contextual repeatability). We also addressed whether R estimates were influenced by seven extrinsic factors (moderators): type of cognitive performance measurement, type of cognitive task, delay between tests, origin of the subjects, experimental context, taxonomic class and publication status. We found support for both temporal and contextual repeatability of cognitive performance, with mean R estimates ranging between 0.15 and 0.28. Repeatability estimates were mostly influenced by the type of cognitive performance measures and publication status. Our findings highlight the widespread occurrence of consistent inter-individual variation in cognition across a range of taxa which, like behaviour, may be associated with fitness outcomes.This article is part of the theme issue 'Causes and consequences of individual differences in cognitive abilities'.

Cognition in the field: comparison of reversal learning performance in captive and wild passerines.

Animal cognitive abilities have traditionally been studied in the lab, but studying cognition in nature could provide several benefits including reduced stress and reduced impact on life-history traits. However, it is not yet clear to what extent cognitive abilities can be properly measured in the wild. Here we present the first comparison of the cognitive performance of individuals from the same population, assessed using an identical test, but in contrasting contexts: in the wild vs. in controlled captive conditions. We show that free-ranging great tits (Parus major) perform similarly to deprived, captive birds in a successive spatial reversal-learning task using automated operant devices. In both captive and natural conditions, more than half of birds that contacted the device were able to perform at least one spatial reversal. Moreover, both captive and wild birds showed an improvement of performance over successive reversals, with very similar learning curves observed in both contexts for each reversal. Our results suggest that it is possible to study cognitive abilities of wild animals directly in their natural environment in much the same way that we study captive animals. Such methods open numerous possibilities to study and understand the evolution and ecology of cognition in natural populations.

Stable producer-scrounger dynamics in wild birds: sociability and learning speed covary with scrounging behaviour.

There has been extensive game-theoretic modelling of conditions leading to equilibria of producer-scrounger dichotomies in groups. However there is a surprising paucity of experimental evidence in wild populations. Here, we examine producer-scrounger games in five subpopulations of birds feeding at a socially learnt foraging task. Over four weeks, a bimodal distribution of producers and scroungers emerged in all areas, with pronounced and consistent individual tactic specialization persisting over 3 years. Tactics were unrelated to exploratory personality, but correlated with latency to contact and learn the foraging task, with the late arrivers and slower learners more likely to adopt the scrounging role. Additionally, the social environment was also important: at the broad scale, larger subpopulations with a higher social density contained proportionally more scroungers, while within subpopulations scroungers tended to be central in the social network and be observed in larger foraging flocks. This study thus provides a rare example of a stable, dimorphic distribution of producer-scrounger tactics in a wild population. It further gives support across multiple scales for a major prediction of social foraging theory; that the frequency of scroungers increases with group size.

Immunosuppression Strategies in the Treatment of Hepatocellular Carcinoma in Virgen de las Nieves University Hospital.

BACKGROUND: We describe an observational, retrospective study that included patients who underwent a liver transplantation (LT) for hepatocellular carcinoma (HCC) in our center between 2004 and 2012. METHODS: Clinical variables were recorded for donors and recipients as diagnosis and treatment, immunosuppressive therapy, toxicity, graft dysfunction, recurrence, and exitus. Fifty-eight patients were analyzed. The mean age was 57 ± 8 years. The viral etiology of HCC was 50% (n = 29), alcoholic 26% (n = 15), and others, 24% (n = 14). Regarding initial immunosuppressive strategy (IS), 51 patients (87.9%) were treated with standard regimen with corticosteroids (CS) and tacrolimus (TA), compared with 7 patients with impaired renal function (12.1%) who underwent a delayed therapy with calcineurin inhibitors (CNI) + mycophenolate mophetil (MMF) + CS. Concomitant use of anti-CD25 monoclonal antibodies was less than 10%. Regarding maintenance, 43 patients (74.1%) were treated with MMF + CNI versus 15 treated only with TA (25.9%). RESULTS: Recurrence of HCC was approximately 12%: 7 patients (2 hepatic only, 5 also extra-hepatic). Exitus was established in 19 patients (32.75%); only 3 patients (5.17%) were attributable to HCC. Bivariate studies were conducted according to the initial IS (standard regimen versus delayed therapy) and maintenance therapy (MMF + TA versus TA alone), with no differences in any of them in recurrence, treatment toxicity, graft rejection, and dysfunction. CONCLUSIONS: In our experience with the IS, we found no differences in the development of recurrent disease, treatment toxicity, development of graft dysfunction, or rejection. We believe that individualized immunosuppressive therapy in these patients is safe and effective.

Expression profiling of rectal tumors defines response to neoadjuvant treatment related genes.

To date, no effective method exists that predicts the response to preoperative chemoradiation (CRT) in locally advanced rectal cancer (LARC). Nevertheless, identification of patients who have a higher likelihood of responding to preoperative CRT could be crucial in decreasing treatment morbidity and avoiding expensive and time-consuming treatments. The aim of this study was to identify signatures or molecular markers related to response to pre-operative CRT in LARC. We analyzed the gene expression profiles of 26 pre-treatment biopsies of LARC (10 responders and 16 non-responders) without metastasis using Human WG CodeLink microarray platform. Two hundred and fifty seven genes were differentially over-expressed in the responder patient subgroup. Ingenuity Pathway Analysis revealed a significant ratio of differentially expressed genes related to cancer, cellular growth and proliferation pathways, and c-Myc network. We demonstrated that high Gng4, c-Myc, Pola1, and Rrm1 mRNA expression levels was a significant prognostic factor for response to treatment in LARC patients (p<0.05). Using this gene set, we were able to establish a new model for predicting the response to CRT in rectal cancer with a sensitivity of 60% and 100% specificity. Our results reflect the value of gene expression profiling to gain insight about the molecular pathways involved in the response to treatment of LARC patients. These findings could be clinically relevant and support the use of mRNA levels when aiming to identify patients who respond to CRT therapy.

Ileal carcinoid tumor within Crohn’s disease / Tumor carcinoide ileal en la enfermedad de Crohn

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"Very early" intrahepatic cholangiocarcinoma in cirrhotic patients: should liver transplantation be reconsidered in these patients?

A retrospective cohort multicenter study was conducted to analyze the risk factors for tumor recurrence after liver transplantation (LT) in cirrhotic patients found to have an intrahepatic cholangiocarcinoma (iCCA) on pathology examination. We also aimed to ascertain whether there existed a subgroup of patients with single tumors ≤2 cm ("very early") in which results after LT can be acceptable. Twenty-nine patients comprised the study group, eight of whom had a "very early" iCCA (four of them incidentals). The risk of tumor recurrence was significantly associated with larger tumor size as well as larger tumor volume, microscopic vascular invasion and poor degree of differentiation. None of the patients in the "very early" iCCA subgroup presented tumor recurrence compared to 36.4% of those with single tumors >2 cm or multinodular tumors, p = 0.02. The 1-, 3- and 5-year actuarial survival of those in the "very early" iCCA subgroup was 100%, 73% and 73%, respectively. The present is the first multicenter attempt to ascertain the risk factors for tumor recurrence in cirrhotic patients found to have an iCCA on pathology examination. Cirrhotic patients with iCCA ≤2 cm achieved excellent 5-year survival, and validation of these findings by other groups may change the current exclusion of such patients from transplant programs.

Intrahepatic cholangiocarcinoma or mixed hepatocellular-cholangiocarcinoma in patients undergoing liver transplantation: a Spanish matched cohort multicenter study.

OBJECTIVE: To evaluate the outcome of patients with hepatocellular-cholangiocarcinoma (HCC-CC) or intrahepatic cholangiocarcinoma (I-CC) on pathological examination after liver transplantation for HCC. BACKGROUND: Information on the outcome of cirrhotic patients undergoing a transplant for HCC and with a diagnosis of HCC-CC or I-CC by pathological study is limited. METHODS: Multicenter, retrospective, matched cohort 1:2 study. STUDY GROUP: 42 patients undergoing a transplant for HCC and with a diagnosis of HCC-CC or I-CC by pathological study; and control group: 84 patients with a diagnosis of HCC. I-CC subgroup: 27 patients compared with 54 controls; HCC-CC subgroup: 15 patients compared with 30 controls. Patients were also divided according to the preoperative tumor size and number: uninodular tumors 2 cm or smaller and multinodular or uninodular tumors 2 cm or larger. Median follow-up: 51 (range, 3-142) months. RESULTS: The 1-, 3-, and 5-year actuarial survival rate differed between the study and control groups (83%, 70%, and 60% vs 99%, 94%, and 89%, respectively; P < 0.001). Differences were found in 1-, 3-, and 5-year actuarial survival rates between the I-CC subgroup and their controls (78%, 66%, and 51% vs 100%, 98%, and 93%; P < 0.001), but no differences were observed between the HCC-CC subgroup and their controls (93%, 78%, and 78% vs 97%, 86%, and 86%; P = 0.9). Patients with uninodular tumors 2 cm or smaller in the study and control groups had similar 1-, 3-, and 5-year survival rate (92%, 83%, 62% vs 100%, 80%, 80%; P = 0.4). In contrast, patients in the study group with multinodular or uninodular tumors larger than 2 cm had worse 1-, 3-, and 5-year survival rates than their controls (80%, 66%, and 61% vs 99%, 96%, and 90%; P < 0.001). CONCLUSIONS: Patients with HCC-CC have similar survival to patients undergoing a transplant for HCC. Preoperative diagnosis of HCC-CC should not prompt the exclusion of these patients from transplant option.

Experience of the transplant unit from Virgen de las Nieves Hospital in using liver grafts from asystolic donors.

Given the shortage of donors, it has become increasingly necessary to use alternative sources to meet the growing demand for organs, and evolution in the use of asystolic donors is proving to be an important resource in helping to meet those needs. The goal of this study is to describe the initial results of our experience with Type II asystolic donation. An observational retrospective study was conducted to analyze the variables of four cases in this type of donation. After the analysis we conclude that, despite the limited number of cases in our series, the results are compatible with larger series and permit us to continue to value this method as a resource for broadening the donor pool.

Liver transplantation using low-weight recipients from a graft split program.

We present our experience with a split liver (SL) program shared with the children's liver transplantation (LT) program from 2 different hospitals in the use of partial grafts from cadaver donors in brain death. We describe an observational, retrospective study, which included patients who underwent a SL transplantation in our center between January 2006 and December 2012. Clinical variables were recorded of both donors and recipients and their data were analyzed using SPSS 19.0 software. Of a total of 204 LT, 4 (2%) patients were treated with a SL. The causes of LT were alcoholic cirrhosis in 2 cases, cryptogenic cirrhosis, and primary biliary cirrhosis (PBC). In all cases there was a temporary portocaval shunt. The confluence of the hepatic veins of the recipient was anastomosed to the donor vena cava and arterial anastomosis was performed. The reconstruction was hepato-choledochal in all cases. There were no cases of postreperfusion syndrome or vascular thrombosis and no retransplantation was necessary. Currently, 3 of the 4 cases are still alive. Death in the other patient was due to mesenteric ischemia. Our center has participated in the development of a protocol that considers the indication of this technique provided expert groups are involved in its development, regardless of hospital level. This will expand the pool of donors and partially solve the current problems with available grafting.

Microarray profiling of mononuclear peripheral blood cells identifies novel candidate genes related to chemoradiation response in rectal cancer.

Preoperative chemoradiation significantly improves oncological outcome in locally advanced rectal cancer. However there is no effective method of predicting tumor response to chemoradiation in these patients. Peripheral blood mononuclear cells have emerged recently as pathology markers of cancer and other diseases, making possible their use as therapy predictors. Furthermore, the importance of the immune response in radiosensivity of solid organs led us to hypothesized that microarray gene expression profiling of peripheral blood mononuclear cells could identify patients with response to chemoradiation in rectal cancer. Thirty five 35 patients with locally advanced rectal cancer were recruited initially to perform the study. Peripheral blood samples were obtained before neaodjuvant treatment. RNA was extracted and purified to obtain cDNA and cRNA for hybridization of microarrays included in Human WG CodeLink bioarrays. Quantitative real time PCR was used to validate microarray experiment data. Results were correlated with pathological response, according to Mandard´s criteria and final UICC Stage (patients with tumor regression grade 1-2 and downstaging being defined as responders and patients with grade 3-5 and no downstaging as non-responders). Twenty seven out of 35 patients were finally included in the study. We performed a multiple t-test using Significance Analysis of Microarrays, to find those genes differing significantly in expression, between responders (n = 11) and non-responders (n = 16) to CRT. The differently expressed genes were: BC 035656.1, CIR, PRDM2, CAPG, FALZ, HLA-DPB2, NUPL2, and ZFP36. The measurement of FALZ (p = 0.029) gene expression level determined by qRT-PCR, showed statistically significant differences between the two groups. Gene expression profiling reveals novel genes in peripheral blood samples of mononuclear cells that could predict responders and non-responders to chemoradiation in patients with locally advanced rectal cancer. Moreover, our investigation added further evidence to the importance of mononuclear cells' mediated response in the neoadjuvant treatment of rectal cancer.

Individual personalities predict social behaviour in wild networks of great tits (Parus major).

Social environments have an important effect on a range of ecological processes, and form a crucial component of selection. However, little is known of the link between personality, social behaviour and population structure. We combine a well-understood personality trait with large-scale social networks in wild songbirds, and show that personality underpins multiple aspects of social organisation. First, we demonstrate a relationship between network centrality and personality with 'proactive' (fast-exploring) individuals associating weakly with greater numbers of conspecifics and moving between flocks. Second, temporal stability of associations relates to personality: 'reactive' (slow-exploring) birds form synergistically stable relationships. Finally, we show that personality influences social structure, with males non-randomly distributed across groups. These results provide strong evidence that songbirds follow alternative social strategies related to personality. This has implications not only for the causes of social network structure but also for the strength and direction of selection on personality in natural populations.

Perioperative values of glutathione peroxidase activity and malondialdehyde levels in enolic cirrhotic recipients of a liver transplant.

Reactive oxygen species play a central role in ischemia-reperfusion injury after organ transplantation. They are degraded by endogenous radical scavengers such as antioxidant enzymes. The purpose of this study was to evaluate the temporal variation in glutathione peroxidase (GPX) activity and malondialdehyde (MDA) levels among alcoholic cirrhotic recipients of liver transplantations. The study included 30 recipients: 26 males and 4 females in the provided blood samples before and after transplantation. The results showed significant enhancement of MDA levels at 1 and 6 hours after transplantation: 4.458 ± 2.273 µmol/L and 4.4628 ± 2.405 µmol/L respectively (P < .001). In contrast, GPX activity showed a maximum at 3 days there after 3.541 ± 2,315 nmol/mg protein. In conclusion, although MDA levels show an enormous increase at 1 hour after transplantation suggesting lipid peroxidation, they were compensated by GPX activity thereafter, indicating control of the oxidative stress generated by liver transplantation.

Echocardiographic study in cirrhotic patient candidates for liver transplantation.

We studied 81 cirrhotic patients who were candidates for liver transplantation to evaluate frequently detected cardiac alterations by echocardiographic study. Patients were distributed into three groups: group 1 comprised alcoholic cirrhotic patients (n = 40); group 2, viral cirrhotic patients (hepatitis C or B virus) (n = 35); and group 3, patients with primary biliary cirrhosis (n = 6). Cardiac chambers and diastolic functions were estimated by two-dimensional transthoracic echocardiography in M mode and Doppler. The most frequently detected cardiac structural alterations were left atrial diameter enlargement in 100% of the women and 40% of the men in group 1; 87.5% of the women and 15.4% of the men in group 2; and 33.3% of the women in group 3. Interventricular wall thickness enlargement in 50% of the women and 27.8% of the men in group 1, 25% of the women and 30.8% of the men in group 2, and 16.4% of the women in group 3. The prevalence of diastolic dysfunction was 45% in group 1, 32.3% in group 2, and 16.4% in group 3 (P > .05). There were no significant differences between the groups in cardiac chamber dimensions, left ventricular wall thickness, or prevalence of diastolic dysfunction.

Social networks predict patch discovery in a wild population of songbirds.

Animals use social information in a wide variety of contexts. Its extensive use by individuals to locate food patches has been documented in a number of species, and various mechanisms of discovery have been identified. However, less is known about whether individuals differ in their access to, and use of, social information to find food. We measured the social network of a wild population of three sympatric tit species (family Paridae) and then recorded individual discovery of novel food patches. By using recently developed methods for network-based diffusion analysis, we show that order of arrival at new food patches was predicted by social associations. Models based only on group searching did not explain this relationship. Furthermore, network position was correlated with likelihood of patch discovery, with central individuals more likely to locate and use novel foraging patches than those with limited social connections. These results demonstrate the utility of social network analysis as a method to investigate social information use, and suggest that the greater probability of receiving social information about new foraging patches confers a benefit on more socially connected individuals.

Gene network profiling before and after transplantation in alcoholic cirrhosis liver transplant recipients.

The main objective of this study was to define a gene network profile network in liver transplant recipients with alcoholic cirrhosis before and after liver transplantation. Genes were selected from data obtained in a previous study of liver transplant recipients with alcoholic cirrhosis. Selected up-regulated genes were further validated by quantitative real-time polymerase chain reaction in different groups of liver transplant recipients with alcoholic cirrhosis (n=5). Selected genes up-regulated before transplantation were: TNFRSF9 (tumor necrosis factor [TNF] receptor superfamily, member 9); IL2RB (interleukin-2 receptor beta); BCL2L2 (BCL2-like 2); NOX5 (NADPH) oxidase, EF-hand calcium binding domain 5); PEX5 (peroxisomal biogenesis factor 5); PPARG (peroxisome proliferator-activated receptor gamma); NIBP (IKK2 binding protein); NKIRAS2 (NFKappaBeta inhibitor interacting Ras-like 2); IL4 (interleukin-4); IL-4R (interleukin 4 receptor); ADH1A (alcohol dehydrogenase 1A, class 1); ALDH1L1 (aldehyde dehydrogenase 1 family, member L1); MPO (myeloperoxidase); NPPA (natriuretic peptide precursor A); BCL2A1 (BCL2-related protein A1); GADD45A (growth arrest and DNA-damage-inducible alpha); TEGT (Bax inhibitor 1); PIK3CA (phosphoinositide-3-kinase, catalytic, alpha polypeptide); IFNGR2 (interferon gamma receptor 2); JAK2 (Janus Kinase 2); FAS (Fas, TNF receptor superfamily, member 6); TANK (TRAF family member-associated NFKB activator); TTRAP (TRAF and TNF receptor-associated protein); and ANXA5 (annexin A5).

Hepatopulmonary syndrome among cirrhotic candidates for liver transplantation.

This study assess of hepatopulmonary syndrome (HPS) prevalence and the influence of etiology among cirrhotic patients due to an alcoholic or viral etiology. We examined the records of patients were distributed as Group 1, alcoholic (n = 40) and Group 2, hepatic cirrhosis of viral etiology (n = 35). Hepatic cirrhosis status was estimated by CHILD and MELD scores. Presence of clinical ascites spell out was noted as well as size and diastolic functions of the cardiac chambers using two-dimensional transthoracic echocardiography in M mode and by Doppler. HPS was studied with agitated saline serum and intravenous contrast administration. HPS was considered to be present when serum or contrast passed to the left chamber before the 5th cardiac cycle. There was no significant differences among related to sex, age, cirrhosis status or ascites. HPS frequency was 35% in Group 1 versus 64.7% among Group 2-Patients (P = .01). Taking into account the results, we concluded that HPS frequency was related to cirrhotic etiology. Upon multivariate analysis a patients with cirrhosis from viral etiology showed significantly increased HPS frequency compared with those displaying cirrhosis of an alcoholic etiology.

Perioperative levels of glutathione reductase in liver transplant recipients with hepatitis C virus cirrhosis.

Surgical intervention causes oxidative stress leading to an adaptive responses by the body. To evaluate changes in the defense capacity of antioxidant enzymes, we determined the activity of glutathione reductase (GR) levels among liver transplant recipients with due to hepatitis C virus cirrhosis. The study was performed in 22 patients (16 males and 6 females) of average ages 52.63 ± 5.49 years for males and 59.67 ± 5.65 years for females. Blood samples for glutathione reductase activity were drawn on admission before as well as at 1, 6, and 12 h and 1, 2, 3, 5 and 7 days after the liver transplantation. Perioperative glutathione reductase levels were significant (P = .014) over the period using Bonferroni tests. GR activity reached a maximum (15.6112 ± 6.56035 nmol/mg protein) at 3 days after liver transplantation (T3d) (P = .001). The increased GR activity values detected perioperatively indicated scavenging of reactive oxygen species generated after liver transplantation of hepatitis C virus cirrhosis patients.