Onyx®, A New Tool for Intraoperative Localization of Liver Lesions.

BACKGROUND: Precise preoperative localization of liver tumors facilitates successful surgical procedures, Intraoperative ultrasonography is a sensitive imaging modality. However, the presence of small non-palpable isoechoic intraparenchymal lesions may be challenging intraoperatively. METHODOLOGY AND MATERIAL DESCRIPTION: Onyx® is a non-adhesive liquid agent comprised of ethylene-vinyl alcohol usually used dissolved in dimethyl-sulfoxide and suspended micronized tantalum powder to provide contrast for visualization under fluoroscopy and ultrasonography and a macroscopic black shape. This embolization material has been increasingly used for the embolization of intracranial arteriovenous malformations. We present the novel application of Onyx® on liver surgery. CURRENT STATUS: We present the case of a female, 55 years-old, whose medical history revealed an elective sigmoidectomy (pT3N1a). After 17 months of follow up, by PET-CT scan, the patient was diagnosed of a small intraparenchymal hypo-attenuated 13 mm tumor located at segment V consistent with metachronous colorectal liver metastasis. Open metastasectomy was performed, ultrasonography-guided Onyx® infusion was delivered the day after, intraoperative ultrasonography showed a palpable hyperechoic material with a posterior acoustic shadowing artifact around the lesion. Onyx® is a promising new tool, without any previous application on liver surgery, feasible with advantages in small not palpable intraparenchymal liver lesions.

Searching for Heavy Dark Matter near the Planck Mass with XENON1T.

Multiple viable theoretical models predict heavy dark matter particles with a mass close to the Planck mass, a range relatively unexplored by current experimental measurements. We use 219.4 days of data collected with the XENON1T experiment to conduct a blind search for signals from multiply interacting massive particles (MIMPs). Their unique track signature allows a targeted analysis with only 0.05 expected background events from muons. Following unblinding, we observe no signal candidate events. This Letter places strong constraints on spin-independent interactions of dark matter particles with a mass between 1×10^{12} and 2×10^{17} GeV/c^{2}. In addition, we present the first exclusion limits on spin-dependent MIMP-neutron and MIMP-proton cross sections for dark matter particles with masses close to the Planck scale.

First Dark Matter Search with Nuclear Recoils from the XENONnT Experiment.

We report on the first search for nuclear recoils from dark matter in the form of weakly interacting massive particles (WIMPs) with the XENONnT experiment, which is based on a two-phase time projection chamber with a sensitive liquid xenon mass of 5.9 ton. During the (1.09±0.03) ton yr exposure used for this search, the intrinsic ^{85}Kr and ^{222}Rn concentrations in the liquid target are reduced to unprecedentedly low levels, giving an electronic recoil background rate of (15.8±1.3) events/ton yr keV in the region of interest. A blind analysis of nuclear recoil events with energies between 3.3 and 60.5 keV finds no significant excess. This leads to a minimum upper limit on the spin-independent WIMP-nucleon cross section of 2.58×10^{-47} cm^{2} for a WIMP mass of 28 GeV/c^{2} at 90% confidence level. Limits for spin-dependent interactions are also provided. Both the limit and the sensitivity for the full range of WIMP masses analyzed here improve on previous results obtained with the XENON1T experiment for the same exposure.

Search for New Physics in Electronic Recoil Data from XENONnT.

We report on a blinded analysis of low-energy electronic recoil data from the first science run of the XENONnT dark matter experiment. Novel subsystems and the increased 5.9 ton liquid xenon target reduced the background in the (1, 30) keV search region to (15.8±1.3) events/(ton×year×keV), the lowest ever achieved in a dark matter detector and ∼5 times lower than in XENON1T. With an exposure of 1.16 ton-years, we observe no excess above background and set stringent new limits on solar axions, an enhanced neutrino magnetic moment, and bosonic dark matter.

Pneumococcal serotypes in children, clinical presentation and antimicrobial susceptibility in the PCV13 era.

The aim was to analyse invasive pneumococcal disease (IPD) serotypes in children aged ⩽17 years according to clinical presentation and antimicrobial susceptibility. We conducted a prospective study (January 2012-June 2016). IPD cases were diagnosed by culture and/or real-time polymerase chain reaction (PCR). Demographic, microbiological and clinical data were analysed. Associations were assessed using the odds ratio (OR) and 95% confidence intervals (CI). Of the 253 cases, 34.4% were aged <2 years, 38.7% 2-4 years and 26.9% 5-17 years. Over 64% were 13-valent pneumococcal conjugate vaccine (PCV13) serotypes. 48% of the cases were diagnosed only by real-time PCR. Serotypes 3 and 1 were associated with complicated pneumonia (P < 0.05) and non-PCV13 serotypes with meningitis (OR 7.32, 95% CI 2.33-22.99) and occult bacteraemia (OR 3.6, 95% CI 1.56-8.76). Serotype 19A was more frequent in children aged <2 years and serotypes 3 and 1 in children aged 2-4 years and 5-17 years, respectively. 36.1% of cases were not susceptible to penicillin and 16.4% were also non-susceptible to cefotaxime. Serotypes 14, 24F and 23B were associated with non-susceptibility to penicillin (P < 0.05) and serotypes 11, 14 and 19A to cefotaxime (P < 0.05). Serotype 19A showed resistance to penicillin (P = 0.002). In conclusion, PCV13 serotypes were most frequent in children aged ⩽17 years, mainly serotypes 3, 1 and 19A. Non-PCV13 serotypes were associated with meningitis and occult bacteraemia and PCV13 serotypes with pneumonia. Non-susceptibility to antibiotics of non-PCV13 serotypes should be monitored.

Diffuse double-layer structure in mixed electrolytes considering ions as dielectric spheres.

The structure of the diffuse part of the electric double layer at solid-electrolyte solution interfaces is examined using a theoretical model that takes into account the finite ion size by modeling the solution as a suspension of polarizable insulating spheres in water. This formalism is applied to mixed electrolyte solutions using the "Boublik-Mansoori-Carnahan-Starling-Leland" (BMCSL) theory for the steric interactions among ions. It is shown that the ionic size differences have a strong bearing on the diffuse part of the electric double-layer structure of these systems. Moreover, for strong potential values, the different size-related effects become important even for binary electrolyte solutions due to the presence of H+ and OH- ions that are substantially smaller than hydrated ions originated from salt dissociation. The obtained results display some of the qualitative features observed in experiments on aqueous systems that are generally interpreted in terms of totally different mechanisms.

UV-B radiation reduces in vitro germination of Metarhizium anisopliae s.l. but does not affect virulence in fungus-treated Aedes aegypti adults and development on dead mosquitoes.

AIMS: Control of diurnal Aedes aegypti with mycoinsecticides should consider the exposure of fungus-treated adults to sunlight, and especially to UV-B radiation that might affect activity of conidia applied on the mosquito's surface. METHODS AND RESULTS: Germination of Metarhizium anisopliae s.l. IP 46 conidia on SDAY medium was not affected at the lowest level of radiation with UV-B, 0·69 kJ m-2 , but was retarded and reduced at higher 2·075 and 4·15 kJ m-2 , and completely inhibited at ≥8·3 kJ m-2 . In contrast, germination of conidia applied onto fibreglass nettings and exposed from 0 to 16·6 kJ m-2 did not differ significantly among levels of irradiance exposure and the controls. There was also no significant impact of UV-B up to 16·6 kJ m-2 on the adulticidal activity of IP 46 and on the subsequent conidiogenesis on cadavers. The Quaite-weighted UV-B irradiance in the laboratory (1152 mW m-2 ) was higher than the natural sunlight irradiance observed in the city of Goiânia in Central Brazil on midday (706 mW m-2 in August to 911 mW m-2 in October 2015). CONCLUSIONS: UV-B does not impair the activity of IP 46 conidia applied previously to radiation on A. aegypti adults. SIGNIFICANCE AND IMPACT OF THE STUDY: Findings contribute to a better understanding of the effectiveness of M. anisopliae against day-active A. aegypti and its potential for biological mosquito control.

New insights into the infection of the American cockroach Periplaneta americana nymphs with Metarhizium anisopliae s.l. (Ascomycota: Hypocreales).

AIMS: To study the marked resistance of Periplaneta americana to entomopathogenic Metarhizium anisopliae. METHODS AND RESULTS: The low susceptibility of 4th instar nymphs applied topically with conidia seemed to be related to an active removal of conidia by the cockroach and to a disabled or retarded germination and subsequent development of conidia on the cuticle (up to 80% germination in the next 7 days after application). Inhibitions or delays of germination were related to the composition of the epicuticular fatty acids (30·1% w/w oleic, 28·3% w/w linoleic, 24·5% w/w palmitic and 11·7% w/w stearic acid) reported here. Propagules invading the nymphs through the cuticle took at least 3 days to reach the haemocoel, and no propagules were found after day 8 post-treatment. Strain IP 46 infected >50% of nymphs treated with doses ≥2 × 104  hyphal bodies (HB) nymph-1 and reduced the survival of nymphs ≤50%. Most nymphs (>70%) survived after injection of 6 × 103 and 2 × 103  HB nymph-1 . CONCLUSIONS: Findings emphasize a distinct resistance of nymphs of the American cockroach to infections by M. anisopliae. SIGNIFICANCE AND IMPACT OF THE STUDY: Our findings provide support for the development of biological control of this synanthropic cockroach pest.

Bacteremia in previously healthy children in emergency departments: clinical and microbiological characteristics and outcome.

A blood culture (BC) is frequently requested in both patients with a suspected occult bacteremia/invasive infection as well as those with certain focal infections. Few data are available on the characteristics of patients in whom a bacteremia is identified in the Pediatric Emergency Department (PED). A prospective multicenter registry was established by the Spanish Pediatric Emergency Society. Epidemiological data, complementary test results, clinical management, and final outcome were recorded. Data from the first three years of the registry were analyzed. A true bacterial pathogen grew in 932 of 65,169 BCs collected [1.43 %; 95 % confidence interval (CI) 1.34-1.51 %], with 711 of them collected in patients without previously known bacteremia risk factors. Among them, 335 (47.1 %) were younger than 1 year old and 467 (65.7 %) had a normal Pediatric Assessment Triangle (PAT) on admission. Overall, the most frequently isolated bacterial species was Streptococcus pneumoniae (27.3 %; 47.6 % among patients with an altered PAT). The main pathogens were Escherichia coli (40.3 %) and S. agalactiae (35.7 %) among patients younger than 3 months, S. pneumoniae among patients 3-60 months old (40.0 %), and S. aureus (31.9 %) among patients over 60 months of age. Neisseria meningitidis was the leading cause of sepsis in patients older than 3 months. Eight patients died; none of them had a pneumococcal bacteremia and all had abnormal PAT findings on admission. S. pneumoniae is the main cause of bacteremia in patients without bacteremia risk factors who attended Spanish PEDs. Age and general appearance influence the frequency of each bacterial species. General appearance also influences the associated mortality.

Estimation of the invasive disease potential of Streptococcus pneumoniae in children by the use of direct capsular typing in clinical specimens.

Traditionally, invasiveness indexes have been based on culture methods. We aimed to establish a new classification of the invasive disease potential of pneumococcal serotypes causing invasive pediatric disease in the era of conjugate vaccines in Catalonia, Spain, by adding capsular typing of Streptococcus pneumoniae in direct sample. Two samples of children attended at the University Hospital Sant Joan de Déu (Barcelona, Spain) between 2007 and 2011 were compared: a first sample of 358 children with invasive pneumococcal disease and a second sample of 402 pneumococcal nasopharyngeal carriers selected from 714 healthy children admitted for minor surgical procedures. The most common invasive serotypes were 1 (20.1 %, n = 72), 19A (13.9 %, n = 50), 3 (12.3 %, n = 44), and 7FA (7.5 %, n = 27), whereas the most common serotypes in carriage were 19A (8.7 %, n = 38), 10FC33C (7.8 %, n = 34), 6C (6.9 %, n = 30), and 19FBC (5.5 %, n = 24). We detected a rate of cocolonization of 26.4 % (n = 89) among the 336 samples serotyped in the carriers population. Serotypes 1, 3, and 7FA were significantly associated with high invasiveness. Serotypes 6C, 10FC33C, 23A, 35B, 19FBC, 21, 11AD, 15BC, 23B, 34, and 6A were significantly associated with low invasiveness. Our results proved that the use of molecular techniques in direct sample for both the detection and the capsular identification of Streptococcus pneumoniae is very useful to obtain a more accurate calculation of the invasiveness of the different pneumococcal serotypes.

An exploratory study of the effect of regular aquatic exercise on the function of neutrophils from women with fibromyalgia: role of IL-8 and noradrenaline.

Fibromyalgia (FM) syndrome is associated with elevated systemic inflammatory and stress biomarkers, and an elevated innate cellular response mediated by monocytes and neutrophils. Exercise is accepted as a good non-pharmacological therapy for FM. We have previously found that regular aquatic exercise decreases the release of inflammatory cytokines by monocytes from FM patients. However, its effects on the functional capacity of neutrophils have not been studied. The aim of the present exploratory study was to evaluate, in 10 women diagnosed with FM, the effect of an aquatic exercise program (8months, 2sessions/week, 60min/session) on their neutrophils' function (phagocytic process), and on IL-8 and NA as potential inflammatory and stress mediators, respectively. A control group of 10 inactive FM patients was included in the study. After 4months of the exercise program, no significant changes were observed in neutrophil function (chemotaxis, phagocytosis, or fungicidal capacity) or in IL-8 and NA. However, at the end of the exercise program (8months), a neuro-immuno-endocrine adaptation was observed, manifested by a significant decrease to values below those in the basal state in neutrophil chemotaxis, IL-8, and NA. No significant seasonal changes in these parameters were observed during the same period in the group of non-exercised FM patients. After the 8months of the exercise program, the FM patients had lower concentrations of IL-8 and NA together with reduced chemotaxis of neutrophils compared with the values determined in the same month in the control group of non-exercised FM women. These results suggest that "anti-inflammatory" and "anti-stress" adaptations may be contributing to the symptomatic benefits that have been attributed to regular aquatic exercise in FM syndrome, as was corroborated in the present study by the scores on the Fibromyalgia Impact Questionnaire.

Evaluation of Water Sanitation Health Education Programme: Working with the Knowledge of the Basic Sanitation Services in a Developing Community in Rural Haiti after the 2010 Earthquake.

OBJECTIVE: The aim of this study is to measure the knowledge regarding the new sanitation water system being implemented in Dessources, a rural community in the municipality of Croix-des-Bouquets in Haiti after a two-year intervention programme. DESIGN AND METHODS: A cross-sectional epidemiologic design was used to measure the knowledge of the people in the community using a semi-structured questionnaire. Data collection followed a face-to-face interview process in all houses of the community. The instrument content validity was performed by a panel of experts followed by Cronbach's alpha test to establish the reliability of knowledge scale. In addition, association measures were done using Stata 11.0 statistical package. RESULTS: Content validity test were performed with minimum changes and an alpha of 0.74 was obtained for the scale. Response rate was 65.57% (41/60 houses); non-participants were only those who did not meet the inclusion criteria. Most of the participants (77.5%) were 21-49 years old and 85% had been living in the community for more than 20 years. Bivariate analysis showed that the people of Dessources had adequate knowledge. Significant differences, however, were found among the zones that are not in use of the new sanitary systems and among families with more than seven members per house. CONCLUSIONS: Differences found can be explained based on the Rogers theoretical diffusion of innovation model. The evaluation shows that people of Dessources in Haiti have a high knowledge regarding the new water sanitation system and provided evidence of an adequate health education programme intervention.

[General adverse reactions to contrast agents. Classification and general concepts]. / Reacciones adversas generales a los contrastes. Clasificación y conceptos generales.

General adverse reactions to intravenous contrast agents are uncommon, although relevant due to the growing number of radiologic tests that use iodinated or gadolinium-based contrast agents. Although most of these reactions are mild, some patients can experience significant reactions that radiologists should know how to prevent and treat.

A novel study, textbook outcome in adrenalectomy: retrospective observational study in an endocrine surgical unit.

Textbook outcome is a multidimensional quality management tool that uses a set of traditional surgical measures to reflect an "ideal" surgical result for a particular pathology. Retrospective study of all patients undergoing scheduled for adrenal tumors surgery at an endocrine surgery unit from January 2010-December 2022. The definition of Textbook Outcome were: R0 resection, no Clavien-Dindo ≥ IIIa complications, no prolonged stay (< P75), no readmissions, and no mortality in the first 30 days. The main objective was to analyze the rate of Textbook Outcome obtained. One hundred and five patients were included in the study. Textbook Outcome was achieved in 71.4%. Surgical approach (p < 0.001), Charlson scale (p = 0.031), American Society of Anesthesiologists Classification (p = 0.047) and surgical time (p < 0.001) were all significantly associated with the achievement of Textbook Outcome. The laparoscopic approach was associated as an independent factor with obtaining Textbook Outcome (OR:5.394; p = 0.016), as was surgical time (OR:0.986; p = 0.004). Textbook Outcome is a novel, useful, easy-to-interpret tool for measuring results in adrenal surgery. The laparoscopic approach is associated with a higher rate of "ideal" surgical results. The study was registered in the public accessible database clinicaltrials.gov with the ClinicalTrials.gov ID: NCT05888753.

Effects of habitual exercise on the eHsp72-induced release of inflammatory cytokines by macrophages from obese Zucker rats.

Regular exercise is a good non-pharmacological treatment of metabolic syndrome in that it improves obesity, diabetes, and inflammation. The 72 kDa extracellular heat shock protein (eHsp72) is released during exercise, thus stimulating the inflammatory responses. The aim of the present work was to evaluate the effect of regular exercise on the eHsp72-induced release of IL-1ß, IL-6, and TNFα by macrophages from genetically obese Zucker rats (fa/fa) (ObZ), using lean Zucker (LZ) rats (Fa/fa) to provide reference values. ObZ presented a higher plasma concentration of eHsp72 than LZ, and exercise increased that concentration. In response to eHsp72, the macrophages from ObZ released less IL-1ß and TNFα, but more IL-6, than macrophages from LZ. While eHsp72 stimulated the release of IL-1ß, TNFα, and IL-6 in the macrophages from healthy LZ (with respect to the constitutive release), it inhibited the release of IL-1ß and IL-6 in macrophages from ObZ. The habitual exercise improved the release of inflammatory cytokines by macrophages from ObZ in response to eHsp72 (it increased IL-1ß and TNFα, and decreased IL-6), tending to values closer to those determined in healthy LZ. A deregulated macrophage inflammatory and stress response induced by eHsp72 underlies MS, and this is improved by habitual exercise.

Impact of percutaneous cholecystostomy in the management of acute cholecystitis: a retrospective cohort study at a tertiary center.

Laparoscopic cholecystectomy is the gold standard for the treatment of acute cholecystitis (AC). Percutaneous cholecystostomy (PC) for management of AC is increasing; safe and less invasive than laparoscopic cholecystectomy and is very useful in selected patients with severe comorbidities, not suitable for surgery/general anesthesia. We conducted a retrospective observational study between 2016 and 2021 of patients treated with PC for AC, based on the application of the Tokyo guidelines 13/18. The aim was to analyse the clinical results and management of PC in patients undergoing elective or emergency cholecystectomy. Subsequently, a retrospective analytical study was designed to compare various cohorts: elective or emergency surgery and management with PC alone; patients with/without a high surgical risk; and elective vs emergency surgery. Hundred and ninety five patients with AC were treated with PC. Mean age was 74 years, 59.5% were ASA class III/IV, and the mean Charlson comorbidity index was 5.5. Adherence to Tokyo guidelines regarding indication of PC was 50.8%. The rate of complications associated to PC was 12.3% and the 90-day mortality rate was 14.4%. Mean length of time using PC was 10.7 days. Emergency surgery was performed in 4.6%. The overall success rate using PC was 66.7%, and the 1-year readmission rate due to biliary complications after PC was 28.2%. The rate of scheduled cholecystectomy after PC was 22.6%. Conversion to laparotomy and open approach was more frequent in patients who underwent emergency surgery (p = 0.009). No differences were found in 90-day mortality or in the complication rate. PC achieves improvements in the inflammation and infection associated with AC. In our series, it proved to be an effective and safe treatment during the acute episode of AC. Mortality in patients treated with PC is high due to their older age, greater morbidity, and higher Charlson comorbidity index scores. After PC, emergency surgery is uncommon but readmission due to biliary events is high. Cholecystectomy after PC is the definitive treatment and the laparoscopic approach is feasible. Clinical trial registery: The study was registered in the public accessible database clinicaltrials.gov with the ClinicalTrials.gov ID: NCT05153031. Public release date: 12/09/2021.

Patients with COPD hospitalized due to COVID-19 in Spain: a comparison between the first and second wave.

OBJECTIVE: This work aimed to compare the characteristics, progress, and prognosis of patients with COPD hospitalized due to COVID-19 in Spain in the first wave with those of the second wave. MATERIAL AND METHODS: This is an observational study of patients hospitalized in Spain with a diagnosis of COPD included in the SEMI-COVID-19 registry. The medical history, symptoms, analytical and radiological results, treatment, and progress of patients with COPD hospitalized in the first wave (from March to June 2020) versus those hospitalized in the second wave (from July to December 2020) were compared. Factors associated with poor prognosis, defined as all-cause mortality and a composite endpoint that included mortality, high-flow oxygen therapy, mechanical ventilation, and ICU admission, were analyzed. RESULTS: Of the 21,642 patients in the SEMI-COVID-19 Registry, 6.9% were diagnosed with COPD: 1128 (6.8%) in WAVE1 and 374 (7.7%) in WAVE2 (p = 0.04). WAVE2 patients presented less dry cough, fever and dyspnea, hypoxemia (43% vs 36%, p < 0.05), and radiological condensation (46% vs 31%, p < 0.05) than WAVE1 patients. Mortality was lower in WAVE2 (35% vs 28.6%, p = 0.01). In the total sample, mortality and the composite outcome of poor prognosis were lower among patients who received inhalation therapy. CONCLUSIONS: Patients with COPD admitted to the hospital due to COVID-19 in the second wave had less respiratory failure and less radiological involvement as well as a better prognosis. These patients should receive bronchodilator treatment if there is no contraindication for it.

Electron transport measurements in liquid xenon with Xenoscope, a large-scale DARWIN demonstrator.

The DARWIN observatory is a proposed next-generation experiment with 40 tonnes of liquid xenon as an active target in a time projection chamber. To study challenges related to the construction and operation of a multi-tonne scale detector, we have designed and constructed a vertical, full-scale demonstrator for the DARWIN experiment at the University of Zurich. Here, we present the first results from a several-months run with 343kg of xenon and electron drift lifetime and transport measurements with a 53cm tall purity monitor immersed in the cryogenic liquid. After 88days of continuous purification, the electron lifetime reached a value of (664±23)µs. We measured the drift velocity of electrons for electric fields in the range (25-75) V/cm, and found values consistent with previous measurements. We also calculated the longitudinal diffusion constant of the electron cloud in the same field range, and compared with previous data, as well as with predictions from an empirical model.

30-day morbidity and mortality after transoral robotic surgery for human papillomavirus (HPV) associated oropharyngeal squamous cell carcinoma: A retrospective analysis of two prospective adjuvant de-escalation trials (MC1273 & MC1675).

OBJECTIVE: Dose de-escalation of adjuvant therapy (DART) in patients with HPV(+)OPSCC was investigated in two prospective Phase II and III clinical trials (MC1273 and MC1675). We report the 30-day morbidity and mortality associated with primary TORS resection in patients enrolled in these trials. MATERIALS AND METHODS: Patients with HPV(+)OPSCC, who underwent TORS resection between 2013 and 2020 were considered in this analysis. The severity of postoperative transoral bleeding was graded using both the Hinni Grade (HG) transoral surgery bleeding scale and the Common Terminology for Adverse Events (CTCAE) v5.0. Post-surgical complications within 30 days of surgery, as well as rates of tracheostomy, PEG and nasogastric tube placement. RESULTS: 219 patients were included. A total of 7 (3.2 %) patients had a tracheostomy placed at the time of surgery, and all were decannulated within 26 days (median: 5, range: 2-26). There were 33 (15.1 %) returns to the emergency department (ED) with 10 (4.6 %) patients requiring readmission. Using the HG scale, 10 (4.6 %) patients experienced ≥ Grade 3 bleeding with no Grade 5 or 6 bleeds. In contrast, using the CTCAE scale, 15 patients (6.8 %) experienced ≥ Grade 3 bleeding with no Grade 5 bleeds. There was one post-operative death in a patient withdrawn from the trial, and no deaths related to hemorrhage. CONCLUSION AND RELEVANCE: TORS for HPV(+)OPSCC in carefully selected patients at a high volume center was associated with low morbidity and mortality.

Altered cellular membrane fluidity levels and lipid peroxidation during experimental pancreas transplantation.

Although the pathogenesis of ischemia reperfusion (IR) injury is based on complex mechanisms, free radicals play a central role. We evaluated membrane fluidity and lipid peroxidation during pancreas transplantation (PT) performed in 12 pigs (six donors and six recipients). Fluidity was measured by fluorescence spectroscopy, and malondialdehyde (MDA) and 4-hydroxyalkenals (4-HDA) concentrations were used as an index of lipid oxidation. Pancreatic tissues were collected as follows: (A) donor, immediately before vascular clamping; (B) graft, following perfusion lavage with University of Wisconsin preservation fluid; (C) graft, after 16 h of cold ischemia; and (D) recipient, 30 min vascular postreperfusion. Fluidity and MDA and 4-HDA concentrations were similar in cases A, B, and C. However, there was significant membrane rigidity and increased lipid peroxidation after reperfusion (D). These findings suggest that reperfusion exaggerates oxidative damage and may account for the rigidity in the membranes of allografts during PT.