Magnetic Characterization by Scanning Microscopy of Functionalized Iron Oxide Nanoparticles.

This study aimed to systematically understand the magnetic properties of magnetite (Fe3O4) nanoparticles functionalized with different Pluronic F-127 surfactant concentrations (Fe3O4@Pluronic F-127) obtained by using an improved magnetic characterization method based on three-dimensional magnetic maps generated by scanning magnetic microscopy. Additionally, these Fe3O4 and Fe3O4@Pluronic F-127 nanoparticles, as promising systems for biomedical applications, were prepared by a wet chemical reaction. The magnetization curve was obtained through these three-dimensional maps, confirming that both Fe3O4 and Fe3O4@Pluronic F-127 nanoparticles have a superparamagnetic behavior. The as-prepared samples, stored at approximately 20 °C, showed no change in the magnetization curve even months after their generation, resulting in no nanoparticles free from oxidation, as Raman measurements have confirmed. Furthermore, by applying this magnetic technique, it was possible to estimate that the nanoparticles' magnetic core diameter was about 5 nm. Our results were confirmed by comparison with other techniques, namely as transmission electron microscopy imaging and diffraction together with Raman spectroscopy. Finally, these results, in addition to validating scanning magnetic microscopy, also highlight its potential for a detailed magnetic characterization of nanoparticles.

A Case Report of Peripheral Nerve Stimulation for Acute Neuropathic Pain in Guillain-Barre Syndrome.

Guillain-Barre syndrome (GBS) is a peripheral demyelinating neuromuscular disorder occasionally associated with pharmacologically refractory neuropathic pain. We present a case of acute neuropathic pain in a 22-year-old man with GBS managed with percutaneous peripheral nerve stimulation (PNS). Following implantation of leads in the bilateral sciatic, femoral, and brachial plexus nerve distribution, the patient experienced significant pain reduction in both the upper and lower extremities. Analgesic and anxiolytic medications were reduced by 33% on the first day and by 78% on day 21. PNS is a minimally invasive, nonpharmacologic modality for treating acute neuropathic pain in GBS patients.

Use of artificial intelligence as an innovative donor-recipient matching model for liver transplantation: results from a multicenter Spanish study.

BACKGROUND & AIMS: There is an increasing discrepancy between the number of potential liver graft recipients and the number of organs available. Organ allocation should follow the concept of benefit of survival, avoiding human-innate subjectivity. The aim of this study is to use artificial-neural-networks (ANNs) for donor-recipient (D-R) matching in liver transplantation (LT) and to compare its accuracy with validated scores (MELD, D-MELD, DRI, P-SOFT, SOFT, and BAR) of graft survival. METHODS: 64 donor and recipient variables from a set of 1003 LTs from a multicenter study including 11 Spanish centres were included. For each D-R pair, common statistics (simple and multiple regression models) and ANN formulae for two non-complementary probability-models of 3-month graft-survival and -loss were calculated: a positive-survival (NN-CCR) and a negative-loss (NN-MS) model. The NN models were obtained by using the Neural Net Evolutionary Programming (NNEP) algorithm. Additionally, receiver-operating-curves (ROC) were performed to validate ANNs against other scores. RESULTS: Optimal results for NN-CCR and NN-MS models were obtained, with the best performance in predicting the probability of graft-survival (90.79%) and -loss (71.42%) for each D-R pair, significantly improving results from multiple regressions. ROC curves for 3-months graft-survival and -loss predictions were significantly more accurate for ANN than for other scores in both NN-CCR (AUROC-ANN=0.80 vs. -MELD=0.50; -D-MELD=0.54; -P-SOFT=0.54; -SOFT=0.55; -BAR=0.67 and -DRI=0.42) and NN-MS (AUROC-ANN=0.82 vs. -MELD=0.41; -D-MELD=0.47; -P-SOFT=0.43; -SOFT=0.57, -BAR=0.61 and -DRI=0.48). CONCLUSIONS: ANNs may be considered a powerful decision-making technology for this dataset, optimizing the principles of justice, efficiency and equity. This may be a useful tool for predicting the 3-month outcome and a potential research area for future D-R matching models.

Inclusion body myositis: diagnosis, pathogenesis, and treatment options.

Inclusion body myositis (IBM) is the most common acquired myopathy in people older than 50 years. IBM typically presents with distal upper extremity weakness accompanied by proximal lower extremity muscle weakness. Associated clinical findings include asymmetric weakness, foot drop, and dysphagia. The pathogenesis of IBM is not clear. In this article the authors briefly discuss postulated pathogenic mechanisms. Although no proven pharmacotherapy exists, some promising candidates are discussed.

BNP as marker of heart dysfunction in patients with liver cirrhosis.

BACKGROUNDS: Patients with liver cirrhosis suffer various degrees of cardiac dysfunction which may be crucial in determining the outcome of surgery. The aim of this study was to determine the role of natriuretic peptides on the assessment of cardiac dysfunction in patients with liver cirrhosis. METHODS: Prospective longitudinal study of 30 patients with hepatic cirrhosis. Severity of disease was assessed according to the Child-Turcotte-Pugh and Model for End Stage Liver Disease (MELD) scores. Cardiac function was assessed using endocrine markers [atrial natriuretic peptide-brain natriuretic peptide (BNP)] and isotopic ventriculography at baseline and after stimulation with dobutamine. RESULTS: The ejection fraction was higher in patients with Child A+B and MELD less than 18 than in patients with advanced liver disease. A significant correlation between BNP plasma levels and MELD values was observed. Dobutamine induced a marked improvement in myocardial performance associated to a decrease in BNP levels. Multivariate analysis showed that BNP has prognostic value as a marker of cardiac ejection fraction. Patients whose baseline BNP concentrations were more than 70 pg/ml had an ejection fraction of around 45%. CONCLUSION: This study has shown that increased baseline BNP concentrations may be regarded together with high Child and MELD scores, as the critical cardiac dysfunction threshold in cirrhotic patients.

Model for end-stage liver disease score-based allocation of donors for liver transplantation: a spanish multicenter experience.

BACKGROUND: Prioritizing the liver transplant waiting list (WL) is subject to great variability. We present the experience of four transplant centers in Andalusia (Southern Spain) with a new consensus model of WL management based on the Model for End-Stage Liver Disease (MELD) score. METHODS: The initial criteria for local prioritizing were: a) cirrhosis with MELD score > or =24, and b) all hepatocellular carcinoma (HCC) admitted to the WL. Fourteen months later new criteria were established: a) cirrhosis with MELD score > or =18, and b) uninodular HCC between 3-5 cm or multinodular HCC (2-3 nodules <3 cm). Access to regional priority was scheduled after three months for patients with cirrhosis or six months for patients with HCC. We analyzed the WL mortality rate, posttransplant survival rate, and overall survival rate over three 14-month periods: A (before implementation of priority criteria), B (initial criteria), and C (current criteria). RESULTS: Priority was given to 36% of recipients in period B and 47% in period C. The WL mortality rate (including removals from WL) was 12.9%, 12.9%, and 10.7% in periods A, B, and C, respectively. One-year graft survival was 79.7%, 72.6%, and 81.2% in the same periods. The overall one-year survival rate for new cases on the WL was 74.9% in period A, 68.6% in period B, and 82.2% in period C. CONCLUSIONS: The allocation system and WL management with the current criteria resulted in lower waiting list mortality without reducing posttransplant survival, leading to better survival for all patients listed.

Assignment of steatotic livers by the Mayo model for end-stage liver disease.

Prognosis after liver transplantation depends on a combination of recipient and donor variables. The purpose of this study is to define an allocation system of steatotic donor livers relative to recipient model for end-stage liver disease (MELD) score. We reviewed 500 consecutive OLT, computing the MELD score for each recipient. Fatty infiltration in grafts was categorized in no steatosis, 10-30%, 30-60% and > or = 60% steatosis. MELD score did not affect preservation injury and graft dysfunction, which were increased with fat content. Recipient and graft survivals lowered when increasing MELD score. Outcome in low-risk recipients (MELD < or = 9) was not altered with steatosis, except those with > or = 60%. Survival functions in moderate-risk recipients (MELD 10-19) were moderately affected with 10-30% steatosis and severely with those with >30. Exactly 30-60% steatotic grafts work poorly in high-risk recipients (MELD > or = 20), and very poorly with > or = 60% steatosis. Prognosis of candidates is optimally influenced when divergence of recipient-donor risks is presented.

Effect of internal biliary drainage on plasma levels of endotoxin, cytokines, and C-reactive protein in patients with obstructive jaundice.

Preoperative biliary drainage may improve the cytokine and acute-phase response derangements observed in patients with obstructive jaundice. We conducted a prospective longitudinal, before-after trial in our 600-bed teaching hospital. Twenty-four patients with obstructive jaundice were investigated, 11 with benign obstruction and 13 with malignant disease. Endoscopic internal biliary drainage was performed in all patients (7 by papillotomy and 17 by endoprostheses). Endotoxin, tumor necrosis factor alpha (TNF-a), interleukin-6 (IL-6), nitric oxide production, and C-reactive protein (CRP) were determined at admission and on days 2 and 7 after internal biliary drainage was accomplished. Bile cultures were obtained before and at the time of drainage. Endotoxin, IL-6, TNF-a, and CRP were significantly higher in patients with cancer. After internal drainage, endotoxin (11.4 vs. 2 EU/L; p <0.05), TNF-a (87.5 vs. 48 pg/ml; p = 0.03), and IL-6 (324 vs. 232 pg/ml; p <0.05) plasma levels decreased significantly in the early postdrainage period in patients with cancer. Endotoxin, cytokines, as well as the CRP plasma values, however, increased again on day 7 after drainage. This trend was less marked in patients with benign obstruction. Patients with positive bile cultures after drainage displayed higher levels of CRP (115 vs. 62 mg/L; p = 0.03), IL-6 (598 vs. 330 pg/ml; p = 0.04), and endotoxin (10.6 vs. 4.8 EU/L; p = 0.02) than those with negative bile cultures. Biliary tract obstruction is associated with an increase in endotoxin levels, a positive acute-phase response, and plasma cytokine elevation. After biliary drainage a transitory improvement of these alterations was observed, although values remained high 1 week postdrainage. These findings were associated with positive bile cultures.

Influence of marginal donors on liver preservation injury.

PURPOSE: The purpose of this study was to assess the accumulated effects of marginal donor quality factors on liver preservation injury (LPI). METHODS: The most recent 400 consecutive liver transplantations at our institution were reviewed. Marginal liver donor criteria included the following: older than 60 years, an intensive care unit stay under ventilatory support for more than 4 days, a cold ischemia time more than 14 hr, high inotropic drug use, prolonged hypotensive episodes for more than 1 hr and less than 60 mm Hg, a peak serum sodium more than 155 mEq/L, and high levels of bilirubin, alanine transferase, or amino transferase. The type of steatosis (macrovesicular or microvesicular) was quantified in four categories: no steatosis, mild (<30%), moderate (30-60%), and severe (> 60%). LPI was stratified histologically in four levels: no damage, mild, moderate, and severe injury. These variables were included in a logistic regression analysis for prediction of the probability of the appearance of LPI. RESULTS: Five variables showed an independent influence on LPI: high inotropic drug use (odds ratio [OR]=1.56), donor age (OR=1.017 per year), moderate to severe macrovesicular steatosis (OR=3.63), cold ischemia time (OR=1,109 per hour), and prolonged stay in an intensive care unit (OR=1.79). Severe LPI was present in 32.7% of the grafts from donors without any factor of the model; in 46.8% from donors with one factor (P =0.09); in 66.2% from donors with two factors (P =0.006); and in 78.3% from donors with at last three factors (P =0.002) (global P=0.0001; chi2 =21.8). CONCLUSIONS: LPI can be potentially predicted based on donor and graft conditions. Accumulation of factors is correlated with an increased effect on LPI.

Precipitate crystal structure determination in melt spun Mg-1.5wt%Ca-6wt%Zn alloy.

A melt-spun Mg-1.5%wtCa-6wt%Zn alloy was analyzed by means of transmission electron microscopy, energy dispersive X-ray spectroscopy, and scanning transmission electron microscopy. The as-solidified alloy exhibited both spherical matrix precipitates and elongated precipitates at the grain boundaries (grain-boundary films). After heat treatment, the alloy showed faceted precipitates (cuboidal shape), mostly on dislocations. It was found that the observed precipitates are the same compound, Ca2Mg6Zn3. As there was no crystallographic data for this compound in the literature, its crystal structure was investigated by comparison of experimental and simulated selected-area electron-diffraction patterns and high-resolution electron microscopy images. This study indicated that Ca2Mg6Zn3 is a trigonal compound with space group P 3 1c and lattice parameters a = 0.97 nm, c = 1.0 nm.