615 research outputs found

    Plateau insulator transition in graphene

    Full text link
    The quantum Hall effect in a single-layer graphene sample is studied in strong magnetic fields up to 28 T. Our measurements reveal the existence of a metal- insulator transition from filling factor ν=2\nu=-2 to ν=0\nu=0. The value of the universal scaling exponent is found to be κ=0.57\kappa=0.57 in graphene and therefore in a truly two-dimensional system. This value of κ\kappa is in agreement with the accepted universal value for the plateau-insulator transitions in standard quasi two-dimensional electron and hole gases.Comment: 10 pages, 5 figure

    Total orthotopic small bowel transplantation in swine under FK 506

    Get PDF
    Previous experimental studies in rodents and in dogs have established the efficacy of FK 506 in controlling the immunologic events following small bowel or multivisceral transplantation.1–5 To complete the assessment of FK 506 in experimental small bowel transplantation, we present here our experience with the frequently used swine model

    Cohexisting Medullary and Papillary Thyroid Cancer

    Get PDF
    Purpose: Papillary thyroid carcinomas (PTCs) and medullary thyroid carcinomas (MTCs) have always been considered different in terms of their incidence rates, cell origins, and histopathological features. Simultaneous occurrence of both disease entities is very rare. Methods: We describe a series of cases with simultaneous MTC and PTC occurrences in the thyroid gland. Results: From 2,897 patients (mean age, 49.2±12.5; 81% women) who underwent thyroidectomy for cancer between 2000 and 2015, we reviewed 11 cases of simultaneous occurrence of MTCs and PTCs. Multifocal PTC with simultaneous MTC was detected in 5 of the 11 cases (45%). Of these PTC patients, 2 had 2 foci, 2 had 3 foci, and 1 had 4 foci. There was 1 case of multifocal MTC with solitary PTC. One patient presented with “composite thyroid carcinoma” with mixed features of MTCs and PTCs. Eight patients (72%) presented an association with diffuse lymphocytic thyroiditis. The sizes of the tumors were 1.95±0.23 cm vs. 1.20±0.20 cm for PTCs and MTCs, respectively (P=0.531). The prevalence of extrathyroidal extension was 33.1% vs. 30.2% for PTCs and MTCs, respectively (P=0.282). All patients underwent total thyroidectomy and central neck node dissection. Radio iodine was delivered to 44% of patients. Follow-up review revealed 9 disease-free patients and 1 with local neck recurrence, while 1 patient died due to non-thyroid reasons. Conclusion: There are only 30 reports describing a total of 50 cases in the English literature regarding concurrent PTC and MTC in the same gland. This study represents one of the largest case series. Whether the incidence of another cancer in these patients is coincidental, or due to the possible activation of a common tumorigenic pathway for both follicular and parafollicular thyroid cells, remains to be elucidated

    Bacterial Infections Change Natural History of Cirrhosis Irrespective of Liver Disease Severity

    Get PDF
    OBJECTIVES: We assessed the prognostic significance of infections in relation to current prognostic scores and explored if infection could be considered per se a distinct clinical stage in the natural history of cirrhosis. METHODS: We included consecutive patients with cirrhosis admitted to a tertiary referral liver unit for at least 48 h over a 2-year period. Diagnosis of infection was based on positive cultures or strict established criteria. We used competing risk analysis and propensity score matching for data analysis. RESULTS: 501 patients (63% male, 48% alcoholic liver disease, median Model of End-stage Liver Disease (MELD)=17) underwent 781 admissions over the study period. Portal hypertensive bleeding and complicated ascites were the commonest reasons of admission. The incidence of proven bacterial infection was 25.6% (60% community acquired and 40% nosocomial). Survival rates at 3, 6, 12, and 30 months were 83%, 77%, 71%, and 62% in patients without diagnosis of infection, vs. 50%, 46%, 41%, and 34% in patients with diagnosis of infection. Overall survival was independently associated with MELD score (hazards ratio (HR) 1.099), intensive care (ITU) stay (HR 1.967) and bacterial infection (HR 2.226). Bacterial infection was an independent predictor of survival even when patients who died within the first 30 days were excluded from the analysis in Cox regression (HR 2.013) and competing risk Cox models in all patients (HR 1.46) and propensity risk score-matched infected and non-infected patients (HR 1.67). CONCLUSIONS: Infection most likely represents a distinct prognostic stage of cirrhosis, which affects survival irrespective of disease severity, even after recovery from the infective episode

    Intraductal papillary mucinous tumor of bile ducts radiologic and pathologic features: a case report

    Get PDF
    We report a case of a 67-year-old Caucasian man with right upper quadrant abdominal pain. He underwent radiologic investigations that revealed a solid, focal mass, at the V hepatic segment. Because a definitive diagnosis, based on imaging appearance of the lesion, was impossible in our case, we performed a hystopathological investigation but the biopsies were inconclusive. So, the definitive diagnosis of intraductal papillary mucinous tumor of bile ducts was made on surgical resected material.Intraductal papillary neoplasm of the liver (IPNL) is a recently recognized entity which closely resembles an intraductal papillary mucinous tumor (IPMT) of the pancreas

    Safety of neural monitoring in thyroid surgery

    Get PDF
    During thyroid surgery, the functional integrity of the recurrent laryngeal nerve (RLN) is not only threatened by direct nerve injury resulting from accidental transection, clipping or ligation. In fact, indirect trauma, e.g. traction and compression occurring repeatedly throughout gland dissection, contribute to long-term nerve impairment. In order to avoid RLN lesions and preserve nerve function the surgeon must adhere to and comply with a strict standardized intraoperative neuromonitoring (IONM) technique to preserve results, quality and safety.IONM should be a team work between the surgeon and the anesthesiologist

    "Vascular lock" causing splenic perfusion defects during irrevesible electroportation if a locally advanced pancreatic tumor

    Get PDF
    Context. There is little reported experience of irreversible electroporation (IRE) of locally advanced pancreatic tumors (LAP). In literature, few data reported complications. In particular vascular vasoconstriction miming splenic infarcts in humans has never been found. Case report. This report describes the onset of asymptomatic multiple little splenic perfusion defects after the treatment of a LAP localized in the boby tail portion of the pancreas with the application of five percutaneous probes for IRE, in a 79 year-old man. Splenic artery was regularly patent but entirely trapped in the tumor. Conclusion. To the best of our knowledge, until now, no experience concerning percutaneous IRE of pancreatic cancer described that phenomenon. The cause could not be established with certainty and “vascular lock" may be a valid hypothesis. Additional studies are necessary to evaluate its frequency and its exact pathophysiological cause in humans.Context There is little reported experience of irreversible electroporation (IRE) of locally advanced pancreatic tumors (LAP). In literature, few data reported complications. In particular vascular vasoconstriction miming splenic infarcts in humans has never been found. Case report This report describes the onset of asymptomatic multiple little splenic perfusion defects after the treatment of a LAP localized in the body-tail portion of the pancreas with the application of five percutaneous probes for IRE, in a 79-year-old man. Splenic artery was regularly patent but entirely trapped in the tumor. Conclusion To the best of our knowledge, until now, no experience concerning percutaneous IRE of pancreatic cancer described that phenomenon. The cause could not be established with certainty and “vascular lock" may be a valid hypothesis. Additional studies are necessary to evaluate its frequency and its exact pathophysiological cause in humans

    An Easy and Efficient Method for Native and Immunoreactive Echinococcus granulosus Antigen 5 Enrichment from Hydatid Cyst Fluid

    Get PDF
    Background: Currently, the serodiagnosis of cystic echinococcosis relies mostly on crude Echinococcus granulosus hydatid cyst fluid as the antigen. Consequently, available immunodiagnostic tests lack standardization of the target antigen and, in turn, this is reflected on poor sensitivity and specificity of the serological diagnosis. Methodology/Principal Findings: Here, a chromatographic method enabling the generation of highly enriched Antigen 5 (Ag5) is described. The procedure is very easy, efficient and reproducible, since different hydatid cyst fluid (HCF) sources produced very similar chromatograms, notwithstanding the clearly evident and extreme heterogeneity of the starting material. In addition, the performance of the antigen preparation in immunological assays was preliminarily assessed by western immunoblotting and ELISA on a limited panel of cystic echinococcosis patients and healthy controls. Following western immunoblotting and ELISA experiments, a high reactivity of patient sera was seen, with unambiguous and highly specific results. Conclusions/Significance: The methods and results reported open interesting perspectives for the development of sensitive diagnostic tools to enable the timely and unambiguous detection of cystic echinococcosis antibodies in patient sera.This work was supported by Regione Autonoma della Sardegna (http://www.regione.sardegna.it/)Pubblicat
    corecore