186,179 research outputs found
Postoperative cognitive dysfunction after liver transplantation
No full textObjective
Postoperative cognitive dysfunction (POCD) in liver transplant (LT) recipients is defined as a “more than expected” postoperative deterioration in cognitive domains, including short-term and long-term memory, mood, consciousness and circadian rhythm. It is diagnosed, after exclusion of other neurological complications, by using specific neuropsychological tests that need preoperative baseline. The aim of this systematic review was to assess the prevalence of POCD after LT and to analyze patients’ symptoms, type and timing of assessment used.
Methods
PubMed, MEDLINE and The Cochrane Li-brary were searched up from January 1986 to August 2014. Study eligibility criteria are as follows: prospective and retrospective studies on human adult subjects describing prevalence of POCD and/or its sequelae after LT episodes were included.
Results
Eighteen studies were identified. The timing of testing for POCD may vary between different studies and within the single study, ranging from 0.5 to 32weeks. POCD occurs in up to 50% of LT recipient.
Conclusion
Future studies should be focused on detecting preoperative and intraoperative factors associated to POCD in order to carry out appropriate strategies aimed at reducing this disabling health condition. Relationship between POCD and long-term outcome needs to be investigated
Usefulness of post-reperfusion lactate clearance for predicting early graft recovery in liver transplant patients: a single centre study
No full textBACKGROUND:
The role of post-reperfusion lactate clearance in assessing graft function has not yet been investigated. The aim of this study was to examine whether lactate clearance, assessed in the post-reperfusion phase, can predict poor graft function in liver transplant patients.
METHODS:
Seventy patients undergoing liver transplantation (LT) were enrolled. Standardised anaesthesia and intraoperative monitoring were applied. The lactate level measured immediately after venous reperfusion and 6 hours later were used to calculate lactate clearance by the following formula: [(reperfusion lactate - 6h post-reperfusion lactate)/reperfusion lactate] ×100. Student's t-test was performed to evaluate differences in lactate clearance between patients with good and poor graft function. Logistic regression was used to assess predictors of poor graft function.
RESULTS:
Post-reperfusion lactate clearance was lower in patients with poor graft function compared to those with good graft function (p=0.0007). Logistic regression showed that post-reperfusion lactate clearance may represent an early predictor of poor graft function (area under receiver operating characteristic curve = 0.83). A lactate clearance cut-off of 59.7% was found (90% sensitivity, 38.3% specificity).
CONCLUSIONS:
Post-reperfusion lactate clearance may be useful for the early identification of poor graft function after LT. In patients with lactate clearance <59.7%, it could be useful to search for the underlying cause of poor graft function
Photochemical Bromination of 2,5-Dimethylbenzoic Acid as Key Step of an Improved Alkyne-Functionalized Blue Box Synthesis**
No full textCyclobis(paraquat-p-phenylene), also known as "blue box", is a highly electron-deficient macrocycle, widely used as a molecular receptor for small electron-rich molecules. Inserting a reactive functional group onto the molecular structure of this cyclophane is paramount for its inclusion into complex architectures. To this aim, including an alkyne moiety would be ideal, because it can participate in click reactions. However, the synthesis of such alkyne-functionalized cyclophane suffers from several drawbacks: the use of toxic and expensive CCl4, the need for high-pressure reactors, and overall low yield. We have revised the existing synthesis of this cyclophane derivative bearing an alkyne moiety, to overcome all these limitations. In particular, photochemical radical bromination is adopted to obtain a sensitive intermediate. We demonstrated that the synthesized host molecule can be functionalized via click reactions and take part in radical-radical interactions. Our work makes a key functionalized paraquat macrocycle more accessible, facilitating the development of novel redox-responsive systems
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Prediction of poor graft function by means of gastric tonometry in patients undergoing liver transplantation
No full textINTRODUCTION. Splanchnic hypoperfusion appears to play a key role in the failure of functional recovery of the graft after orthotopic liver transplantation (LT). The aim of this study was to determine if alterations of tonometric parameters, which are related to splanchnic perfusion, could predict poor graft function in patients undergoing LT.
MATERIALS AND METHODS:
After Ethics Committee approval, 68 patients undergoing LT were enrolled. In all the patients, regional-arterial CO2 gradient (Pr-aCO2) was recorded; in addition, the difference between Pr-aCO2 recorded at anhepatic phase (T1) and at the end of surgery (T2) (T2- T1 = ΔPr-aCO2) was calculated. Poor graft function was determined on the basis of Toronto's classification 72 hours after LT. Student t-test and logistic regression analysis were used for statistical purpose. Results. ΔPr-aCO2 was significantly greater in patients with poor graft function (3.5 ± 13.2) compared to patients with good graft function (-5.8 ± 12.3) (p = 0.014). The logistic regression analysis showed that the ΔPr-aCO2 was able to predict the onset of poor graft function (p = 0.037). A value of ΔPr-aCO2 ≥ -4 was associated with poor graft function with a sensibility of 93.3% and a specificity of 42.3%. CONCLUSION. Our study suggests that the change of Pr-aCO2 may be a valuable index of graft dysfunction. Gastric tonometry might give early prognostic information on the graft outcome, and it may aid clinicians in planning a more strict follow-up and proper interventions in order to improve graft survival
Low values of left ventricular ejection time in the post-anhepatic phase may be associated with occurrence of primary graft dysfunction after orthotopic liver transplantation: results of a single-centre case-control study
No full textAbstract. – BACKGROUND: Previous investi- gations on risk factors for orthotopic liver trans- plantation (OLT) surgery have not analyzed he- modynamic aberrations in great detail. Moreover, the usefulness of esophageal Doppler monitor- ing has not been extensively studied in this clini- cal setting. The aim of this study was to evaluate if the occurrence of primary graft dysfunction (PGD) may be anticipated by hemodynamic in- dexes measured by esophageal Doppler (ED) monitoring system as well as by pulmonary artery catheter (PAC) in patients undergoing OLT.
MATERIALS AND METHODS: 38 OLT recipi- ents were studied. Patients with acute liver fail- ure or having non treated esophageal varices and those transplanted with marginal donors were excluded from the study. The haemodynam- ic data – measured by ED monitoring system (HemosonicTM 100, Arrow, OK, USA) and PAC – collected at the following 3 time points were considered for statistical analysis: 30 minutes after the induction of anesthesia but before skin incision, T0; 20 minutes after liver dissection, T1; at the beginning of biliary reconstruction, T2. On the basis of early outcome (72 hours after OLT), patients were distinguished into two groups: those with PGD (grade III-IV of Toronto classifi- cation) and those without PGD (grade I-II).
RESULTS: LVETc (left ventricular ejection time) values, registered at the beginning of biliary re- construction (T2), were lower in patients with PGD compared to those without PGD (p < 0.000), while there were no differences in hemodynamic para- meters derived from PAC between the two groups.
CONCLUSIONS: Since LVETc is related to pre- load, the results of this study would suggest that normovolemia could be the end point of a fluid replacement strategy in OLT setting
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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