673 research outputs found
Successful Treatment of Postoperative External Biliary Fistula by Selective Nasobiliary Drainage
A 25-year old man presented with a high output external biliary fistula after an operation for a giant
hydatid cyst of the liver. Endoscopic sphincterotomy was inadequate to close the fistula. A nasobiliary
tube was selectively inserted into the leaking hepatic duct and bile was continuously aspirated. The
fistula and the residual cavity healed completely. Details of the patients' management using this
alternative technique, are discussed
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Effect of Training Load on Post-Exercise Cardiac Biomarkers in Healthy Children and Adolescents: A Systematic Review of the Existing Literature.
BACKGROUND: Postexercise release of cardiac biomarkers (cardiac troponins, cTn, and N-terminal pro b-type natriuretic peptide, NT-proBNP) is a well-known phenomenon in adults, although it remains unclear how it manifests in children. The aim of this review is to compare the pre-exercise with the post-exercise measurement of serum cardiac biomarkers, as well as to analyze their post-exercise release based on age, sex, and exercise intensity and duration. METHODS: The terms troponin, football, swimmers, marathon, run, and exercise were used in a literature search at National Library of Medicine. The search was further refined by adding the keywords athletes, children, adolescents, and sport. RESULTS: Fifteen pediatric studies and four studies with a mixed population of adults and children totaled 19 studies for the final analysis. In addition to them, some adult studies have been included for comparison. The kinetics of the cTn and NT-proBNP response after exercise have been the subject of our interest. While the impact of sport type, age, and sex has not yet been fully characterized, the existing data points to considerable impacts of sport intensity and duration on post-exercise biomarkers elevation. Most of the findings came from endurance sports, but the evidence is sparse. Furthermore, there is only limited data on women and less on young adults, African Caribbeans, and professional athletes. CONCLUSIONS: Both amateur and competitive athletes can exhibit post-exercise release of both cTn and NT-proBNP. This is transient and lacks pathological significance, in contrast with adult population, in which exercise-induced increases in in these biomarker levels may not always be benign. While NT-proBNP release is still primarily driven by activity duration, cTnT release is additionally affected by exercise intensity. To define individual ranges of normality for postexercise cTn and NT-proBNP elevation, the role of several confounders (age, sex, sport type/intensity etc.) remains to be further elucidated
Thermoelectric enhancement in PbTe with K, Na co-doping from tuning the interaction of the light and heavy hole valence bands
The effect of K and K-Na substitution for Pb atoms in the rock salt lattice
of PbTe was investigated to test a hypothesis for development of resonant
states in the valence band that may enhance the thermoelectric power. We
combined high temperature Hall-effect, electrical conductivity and thermal
conductivity measurements to show that K-Na co-doping do not form resonance
states but2 can control the energy difference of the maxima of the two primary
valence sub-bands in PbTe. This leads to an enhanced interband interaction with
rising temperature and a significant rise in the thermoelectric figure of merit
of p-type PbTe. The experimental data can be explained by a combination of a
single and two-band model for the valence band of PbTe depending on hole
density that varies in the range of 1-15 x 10^19 cm^-3.Comment: 8 figure
Circadian signatures in rat liver: from gene expression to pathways
<p>Abstract</p> <p>Background</p> <p>Circadian rhythms are 24 hour oscillations in many behavioural, physiological, cellular and molecular processes that are controlled by an endogenous clock which is entrained to environmental factors including light, food and stress. Transcriptional analyses of circadian patterns demonstrate that genes showing circadian rhythms are part of a wide variety of biological pathways.</p> <p>Pathway activity method can identify the significant pattern of the gene expression levels within a pathway. In this method, the overall gene expression levels are translated to a reduced form, pathway activity levels, via singular value decomposition (SVD). A given pathway represented by pathway activity levels can then be as analyzed using the same approaches used for analyzing gene expression levels. We propose to use pathway activity method across time to identify underlying circadian pattern of pathways.</p> <p>Results</p> <p>We used synthetic data to demonstrate that pathway activity analysis can evaluate the underlying circadian pattern within a pathway even when circadian patterns cannot be captured by the individual gene expression levels. In addition, we illustrated that pathway activity formulation should be coupled with a significance analysis to distinguish biologically significant information from random deviations. Next, we performed pathway activity level analysis on a rich time series of transcriptional profiling in rat liver. The over-represented five specific patterns of pathway activity levels, which cannot be explained by random event, exhibited circadian rhythms. The identification of the circadian signatures at the pathway level identified 78 pathways related to energy metabolism, amino acid metabolism, lipid metabolism and DNA replication and protein synthesis, which are biologically relevant in rat liver. Further, we observed tight coordination between cholesterol biosynthesis and bile acid biosynthesis as well as between folate biosynthesis, one carbon pool by folate and purine-pyrimidine metabolism. These coupled pathways are parts of a sequential reaction series where the product of one pathway is the substrate of another pathway.</p> <p>Conclusions</p> <p>Rather than assessing the importance of a single gene beforehand and map these genes onto pathways, we instead examined the orchestrated change within a pathway. Pathway activity level analysis could reveal the underlying circadian dynamics in the microarray data with an unsupervised approach and biologically relevant results were obtained.</p
Unconventional magnetism in all-carbon nanofoam
We report production of nanostructured carbon foam by a high-repetition-rate,
high-power laser ablation of glassy carbon in Ar atmosphere. A combination of
characterization techniques revealed that the system contains both sp2 and sp3
bonded carbon atoms. The material is a novel form of carbon in which
graphite-like sheets fill space at very low density due to strong hyperbolic
curvature, as proposed for ?schwarzite?. The foam exhibits ferromagnetic-like
behaviour up to 90 K, with a narrow hysteresis curve and a high saturation
magnetization. Such magnetic properties are very unusual for a carbon
allotrope. Detailed analysis excludes impurities as the origin of the magnetic
signal. We postulate that localized unpaired spins occur because of topological
and bonding defects associated with the sheet curvature, and that these spins
are stabilized due to the steric protection offered by the convoluted sheets.Comment: 14 pages, including 2 tables and 7 figs. Submitted to Phys Rev B 10
September 200
Can dysglycemia in OGTT be predicted by baseline parameters in patients with PCOS?
BackgroundPolycystic ovary syndrome (PCOS) is considered a risk factor for the development of type 2 diabetes mellitus (T2DM). However, which is the most appropriate way to evaluate dysglycemia in women with PCOS and who are at increased risk are as yet unclear. Aim of the studyTo determine the prevalence of T2DM, impaired glucose tolerance (IGT), and impaired fasting glucose (IFG) in PCOS women and potential factors to identify those at risk. Subjects and methodsThe oral glucose tolerance test (OGTT), biochemical/hormonal profile, and ovarian ultrasound data from 1614 Caucasian women with PCOS and 362 controls were analyzed in this cross-sectional multicenter study. The data were categorized according to age and BMI. ResultsDysglycemia (T2DM, IGT, and IFG according to World Health Organization criteria) was more frequent in the PCOS group compared to controls: 2.2% vs 0.8%, P = 0.04; 9.5% vs 7.4%, P = 0.038; 14.2% vs 9.1%, P = 0.002, respectively. OGTT was essential for T2DM diagnosis, since in 88% of them basal glucose values were inconclusive for diagnosis. The presence of either T2DM or IFG was irrespective of age (P = 0.54) and BMI (P = 0.32), although the latter was associated with IGT (P = 0.021). There was no impact of age and BMI status on the prevalence of T2DM or IFG. Regression analysis revealed a role for age, BMI, fat deposition, androgens, and insulin resistance for dysglycemia. However, none of the factors prevailed as a useful marker employed in clinical practice. ConclusionsOne-third of our cohort of PCOS women with either T2DM or IGT displayed normal fasting glucose values but without confirming any specific predictor for dysglycemic condition. Hence, the evaluation of glycemic status using OGTT in all women with PCOS is strongly supported
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Pacemaker Implantation following Heart Transplantation: Analysis of a Nation-Wide Database.
BACKGROUND: The 2018 United-Network-for-Organ-Sharing (UNOS) allocation-system changes resulted in greater recognition of mechanical circulatory support (MCS), leading to more heart transplantations (HTx) in patients with MCS. We aimed to investigate the effect of the new UNOS allocation system on the need for a permanent pacemaker and associated complications following HTx. METHODS: The UNOS Registry was questioned, to identify patients that received HTx in the US between 2000 and 2021. The primary objectives were to identify risk factors for the need for a pacemaker implantation following HTx. RESULTS: 49,529 HTx patients were identified, 1421 (2.9%) requiring a pacemaker post-HTx. Patients who required a pacemaker were older (53.9 ± 11.5 vs. 52.6 ± 12.8 years, p < 0.001), more frequently white (73% vs. 67%; p < 0.001) and less frequently black (18% vs. 20%; p < 0.001). In the pacemaker group, UNOS status 1A (46% vs. 41%; p < 0.001) and 1B (31% vs. 27%; p < 0.001) were more prevalent, and donor age was higher (34.4 ± 12.4 vs. 31.8 ± 11.5 years; p < 0.001). One-year survival was no different between the groups (HR: 1.08; 95% CI: 0.85, 1.37; p = 0.515). An era effect was observed (per year: OR: 0.97; 95% CI: 0.96, 0.98; p = 0.003), while ECMO pre-transplant was associated with lower risk of a pacemaker (OR: 0.41; 95% CI: 0.19, 0.86; p < 0.001). CONCLUSIONS: While associated with various patient and transplant characteristics, pacemaker implantation does not seem to impact one-year survival after HTx. The need for pacemaker implantation was lower in the more recent era and in patients who required ECMO pre-transplant, a finding explained by recent advances in perioperative care
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Cardiac Imaging and Management of Cardiac Disease in Asymptomatic Renal Transplant Candidates: A Current Update.
Given the high cardiovascular risk accompanying end-stage kidney disease, it would be of paramount importance for the clinical nephrologist to know which screening method(s) identify high-risk patients and whether screening asymptomatic transplant candidates effectively reduces cardiovascular risk in the perioperative setting as well as in the longer term. Within this review, key studies concerning the above questions are reported and critically analyzed. The lack of unified screening criteria and of a prognostically sufficient screening cardiovascular effect for renal transplant candidates sets the foundation for a personalized patient approach in the near future and highlights the need for well-designed studies to produce robust evidence which will address the above questions
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