University of Zurich

About: University of Zurich is a education organization based out in Zurich, Switzerland. It is known for research contribution in the topics: Population & Transplantation. The organization has 50842 authors who have published 124042 publications receiving 5304521 citations. The organization is also known as: UZH & Uni Zurich.

Declining Amphibian Populations: The Problem of Separating Human Impacts from Natural Fluctuations

Abstract: Reports of declining amphibian populations in many parts of the world are numerous, but supporting long-term census data are generally unavailable. Census data from 1979 to 1990 for three salamander species and one frog species at a breeding pond in South Carolina showed fluctuations of substantial magnitude in both the size of breeding populations and in recruitment of juveniles. Breeding population sizes exhibited no overall trend in three species and increased in the fourth. Recent droughts account satisfactorily for an increase in recruitment failures. These data illustrate that to distinguish between natural population fluctuations and declines with anthropogenic causes may require long-term studies.

Microbial status of apical root canal system of human mandibular first molars with primary apical periodontitis after “one-visit” endodontic treatment

Abstract: Objective To assess the in vivo intracanal microbial status of apical root canal system of mesial roots of human mandibular first molars with primary apical periodontitis immediately after one-visit endodontic treatment. The residual intracanal infection was confirmed by correlative light and transmission electron microscopy. Study design Sixteen diseased mesial roots of mandibular first molars were treated endodontically, each in one visit. Mesio-buccal canals were instrumented using stainless steel hand files and mesio-lingual canals with a nickel-titanium rotary system. The canals were irrigated with 5.25% sodium hypochlorite (NaOCl) during the instrumentation procedures, rinsed with 10 mL of 17% ethylenediamine tetraacetic acid (EDTA), and obturated with gutta-percha and zinc oxide eugenol cement. Thereafter, the apical portion of the root of each tooth was removed by flap-surgery. The specimens were fixed, decalcified, subdivided in horizontal plane, embedded in plastic, processed, and evaluated by correlative light and transmission electron microscopy. Results Fourteen of the 16 endodontically treated teeth revealed residual intracanal infection after instrumentation, antimicrobial irrigation, and obturation. The microbes were located in inaccessible recesses and diverticula of instrumented main canals, the intercanal isthmus, and accessory canals, mostly as biofilms. Conclusions The results show (1) the anatomical complexity of the root canal system of mandibular first molar roots and (2) the organization of the flora as biofilms in inaccessible areas of the canal system that cannot be removed by contemporary instruments and irrigation alone in one-visit treatment. These findings demonstrate the importance of stringent application of all nonantibiotic chemo-mechanical measures to treat teeth with infected and necrotic root canals so as to disrupt the biofilms and reduce the intraradicular microbial load to the lowest possible level so as to expect a highly favorable long-term prognosis of the root canal treatment.

Assessment of complications after pancreatic surgery: A novel grading system applied to 633 patients undergoing pancreaticoduodenectomy.

Abstract: Mortality associated with pancreaticoduodenectomy (PD) has decreased dramatically to less than 5% over the past 2 decades in high-volume centers,1–6 but persistent high morbidity rates have remained an important concern for patients, healthcare providers, and payers. While mortality is an objective and easily quantifiable outcome parameter, morbidity is only poorly defined, and this shortcoming has severely hampered conclusive comparisons among centers and within the same institution over time.7–9 Similarly, the identification of risk factors related to specific complications has been difficult. Recognizing this deficiency, there has been several recent attempts to define specific complications related to PD such as pancreatic fistula, either by individual groups10–14 or through consensus statements from a few experts.15 Although important, these definitions have focused only on one specific complication (pancreatic fistula), and typically lack a severity grading system. For example, when a pancreatic fistula is defined as the persistent drainage of amylase-rich fluid during the postoperative course or as radiologic evidence of pancreatic anastomotic disruption, no distinction is made between the minimal criteria and more severe manifestation leading to reoperation or even death. An attempt was recently made by a group of experts in pancreas surgery to grade pancreatic fistula by severity,15 but the grading system is complex, includes multiple subjective criteria, and is not applicable to other types of complications. Therefore, there is persistent need for the availability of a reproducible, simple, and widely acceptable system to grade all complications following PD. A previously reported grading system7–9 was recently revisited and validated in a large cohort of patients undergoing general surgery. An international survey confirmed the simplicity and reproducibility of the new grading system.16 This classification was recently adopted by the International Transplantation Society17 to prospectively monitor the outcome of living liver donors. A key feature facilitating the use of the grading system is that it mostly relies on the therapies used to correct negative events. This is crucial to minimize down grading of complications as even nursing notes can be used to secure appropriate grading in retrospective analyses. Another attractive aspect of the new classification is that it considers the patient perspective through a strong emphasis on long lasting disability. Such a grading system can be adapted to any complication as long as the minimal criteria to define each specific complication are well described and widely accepted. We adapted this novel classification of complications by severity16 to a large cohort of patients, who underwent a PD at Johns Hopkins Hospital, a high-volume center with the availability of a comprehensive database. We used the well-established Johns Hopkins definitions for pancreatic fistula and delayed gastric emptying (DGE),18,19 and stratified them according to severity criteria. Of importance, the John Hopkins definition of pancreatic fistula is consistent with a recent consensus statements.15 The primary aims of the study were to evaluate the feasibility of grading each recorded complication in the database according to the novel classification system, to present specific complications by severity, and to identify risk factors. A secondary aim was to test the novel classification system in comparing the incidence and severity of one type of complication, pancreatic fistula, with a previous series of patients in the same institution. Finally, an attempt was made to evaluate the impact of complications on long-term survival.

The gastroenteropancreatic neuroendocrine cell system and its tumors: the WHO classification.

Abstract: Although well established in medical terminology, the term carcinoid is no longer adequate to cover the entire morphological and biological spectrum of neoplasms of the disseminated neuroendocrine cell system. Therefore, instead of carcinoid, the WHO classification published in 2000 uses the general terms neuroendocrine tumor and neuroendocrine carcinoma. In this review a classification of gastroenteropancreatic neuroendocrine tumors based on the WHO criteria is described. We also classify and comment on the most important tumor entities. On the basis of localization and of various morphological and biological criteria, we distinguish between benign neuroendocrine tumors, tumors with uncertain malignant potential, and tumors showing low-grade and high-grade malignancy.

Determination of jet energy calibration and transverse momentum resolution in CMS

Abstract: Measurements of the jet energy calibration and transverse momentum resolution in CMS are presented, performed with a data sample collected in proton-proton collisions at a centre-of-mass energy of 7TeV, corresponding to an integrated luminosity of 36pb−1. The transverse momentum balance in dijet and γ/Z+jets events is used to measure the jet energy response in the CMS detector, as well as the transverse momentum resolution. The results are presented for three different methods to reconstruct jets: a calorimeter-based approach, the ``Jet-Plus-Track'' approach, which improves the measurement of calorimeter jets by exploiting the associated tracks, and the ``Particle Flow'' approach, which attempts to reconstruct individually each particle in the event, prior to the jet clustering, based on information from all relevant subdetectors