1,849 research outputs found
Resection of sentinel lymph nodes by an extraperitoneal minilaparoscopic approach using indocyanine green for uterine malignancies: a preclinical comparative study
Background. The sentinel lymph node (SLN) concept might minimize surgical aggressiveness in cervical and endometrial malignancies. The aim of the study was to test the feasibility and reliability of minilaparoscopic extraperitoneal SLN excision after indocyanine green (ICG) cervical injection using a high-definition near infrared (NIR) imaging system in an in vivo porcine model. The same procedure was performed using conventional laparoscopic instruments and both outcomes were compared. Methods. Twenty-four animals were equally and randomly divided into a minilaparoscopic group (group A) and a 5-mm conventional laparoscopic group (group B). A high-definition NIR imaging system and a 30 degrees ICG endoscope were used. First, ICG (0.5 mL) was injected in the paracervical region. The SLN coloring time was recorded. An extraperitoneal approach to the SLN was executed with the same CO2 retropneumoperitoneum pressures (10 mm Hg). In both groups, the times for SLN localization and excision, as well as complications, were registered. Finally, a laparotomy was then done to evaluate whether any stained SLN still remained. The same surgical team performed all experiments. Results. SLNs were identified and extraperitoneally excised in all animals without major complications. The SLN localization varied between animals from external iliac to preaortic regions. The surgical times were shorter with minilaparoscopy (39.3 +/- 13 minutes) than with conventional 5-mm instruments (51.3 +/- 14.17 minutes; P = .042). In group B, one stained SLN remained and was only detected by laparotomy. Conclusions. We confirmed the feasibility and reliability of extraperitoneal minilaparoscopic approach for identification, dissection, and excision of SLN using an NIR imaging system and ICG.The author(s) disclosed receipt of the following financial support
for the research, authorship, and/or publication of this article:
This study was supported by the Science & Technology
Foundation (FCT), Portugal—PTDC/SAU-OSM/105578/2008.info:eu-repo/semantics/publishedVersio
Temporal dynamics of spectral reflectance and vegetation indices during canola crop cycle in southern Brazil
The objective of this study was to characterize the variability of spectral reflectance and temporal profiles of vegetation indices
associated with nitrogen fertilization, crop cycle periods, and weather conditions of the growing season in canola canopies in southern Brazil. An
experiment was carried out during the 2013 and 2014 canola growing seasons at EMBRAPA Trigo, Passo Fundo, state of Rio Grande do Sul, Brazil.
The experiment was conducted in a randomized block design with four replications. Five doses of nitrogen top dressing were used as treatments:
10, 20, 40, 80, and 160kg ha-1. Measurements were obtained with the spectroradiometer positioned above the canopy, to construct spectral
reflectance curves for canola and establish temporal profiles for several vegetation indices (SR, NDVI, EVI, SAVI, and GNDVI). In addition, data
on shoot dry matter were obtained and phenological stages were determined. The spectral reflectance curves of canola were reported to change
with canopy growth and development. Temporal profiles of vegetation indices showed two maximum peaks, one before flowering and other after
flowering. The indices SR, NDVI, EVI, SAVI, and GNDVI were able to characterize changes in the canola canopy over time, as a function of
phenological phases, weather conditions, and nitrogen fertilization, throughout the development cycle. Plant growth and development, variations
in crop management, and environmental conditions affect the spectral response of canol
The Role of a Medical Intermediate Care Unit in the Management of Budd-Chiari Syndrome: Case Series
Budd-Chiari syndrome (BCS) has a wide spectrum of presentations, from an asymptomatic status to acute liver failure (ALF). The therapeutic approach depends on disease severity and related etiology with patients with severe forms of presentation classically managed in intensive care units (ICUs). Here, we report a series of five BCS patients managed in a medical intermediate care unit (IntCU), with three of them presenting with acute liver injury. Progression to ALF was seen in three patients, two of whom died, with one being successfully submitted to liver transplantation. IntCUs allow a 24-h patient surveillance and a prompt management of BCS, with less economic impact when compared to ICUs. Mortality was related to the presence of associated comorbidities that limited therapeutic approach.This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors
THERMODYNAMIC SIMULATION OF BIOMASS GAS STEAM REFORMING FOR A SOLID OXIDE FUEL CELL (SOFC) SYSTEM
This paper presents a methodology to simulate a small-scale fuel cell system for power generation using biomass gas as fuel. The methodology encompasses the thermodynamic and electrochemical aspects of a solid oxide fuel cell (SOFC), as well as solves the problem of chemical equilibrium in complex systems. In this case the complex system is the internal reforming of biomass gas to produce hydrogen. The fuel cell input variables are: operational voltage, cell power output, composition of the biomass gas reforming, thermodynamic efficiency, electrochemical efficiency, practical efficiency, the First and Second law efficiencies for the whole system. The chemical compositions, molar flows and temperatures are presented to each point of the system as well as the exergetic efficiency. For a molar water/carbon ratio of 2, the thermodynamic simulation of the biomass gas reforming indicates the maximum hydrogen production at a temperature of 1070 K, which can vary as a function of the biomass gas composition. The comparison with the efficiency of simple gas turbine cycle and regenerative gas turbine cycle shows the superiority of SOFC for the considered electrical power range.26474575
Antibody reactivity against potato apyrase, a protein that shares epitopes with Schistosoma mansoni ATP diphosphohydrolase isoforms, in acute and chronically infected mice, after chemotherapy and reinfection
Schistosoma mansoni ATP diphosphohydrolase isoforms and potato apyrase share conserved epitopes. By enzyme-linked immunosorbent assays, elevated levels of IgM, IgG2a and IgG1 antibody reactivity against potato apyrase were observed in S. mansoni-infected BALB/c mice during the acute phase of infection, while only IgM and IgG1 antibody reactivity levels maintained elevated during the chronic phase of infection. Antibody reactivity against potato apyrase was monitored over an 11-month period in chronically-infected mice treated with oxamniquine. Eleven months later, the level of seropositive IgM decreased significantly (~30%) compared to the level found in untreated, infected mice. The level of seropositive IgG1 decreased significantly four months after treatment (MAT) (61%) and remained at this level even after 11 months. The IgG2a reactivity against potato apyrase, although unchanged during chronic phase to 11 MAT, appeared elevated again in re-infected mice suggesting a response similar to that found during the acute phase. BALB/c mouse polyclonal anti-potato apyrase IgG reacted with soluble egg antigens probably due to the recognition of parasite ATP diphosphohydrolase. This study, for the first time, showed that the IgG2a antibody from S. mansoni-infected BALB mice cross-reacts with potato apyrase and the level of IgG2a in infected mice differentiates disease phases. The results also suggest that different conserved-epitopes contribute to the immune response in schistosomiasis
β-amyloid wall deposit of temporal artery in subjects with spontaneous intracerebral haemorrhage.
Background:
Cerebral Amyloid Angiopathy has been indicated as an important cause of spontaneous non-hypertensive intracerebral haemorrhage (ICH).
Aims:
to analyze the presence of β-amyloid deposit in the temporal artery of consecutive patients with ICH in comparison to control subjects and its relation to APO-E haplotype frequency.
Methods:
We enrolled consecutive patients admitted to Neurosurgery Ward of University Hospital "P. Giaccone" of Palermo with a diagnosis of spontaneous non hypertensive ICH and as control 12 subjects without brain haemorrhage. Biopsy of superficial temporal artery has been performed and β-amyloid deposit was quantified.
Results:
Among 25 subjects with ICH, 10 (40%) had APOE epsilon 2 allele and among these subjects 7 (70%) showed amyloid accumulation on temporal artery specimens, 8 (32%) subjects had APOE epsilon 3 allele and among these subjects only 2 (25%) showed amyloid accumulation on temporal artery specimens, whereas 7 (28%) had APOE epsilon 4 allele and of these, 7 (100%) showed amyloid accumulation on temporal artery specimens. At multivariable logistic regression analysis for the presence of amyloid, predictive factors for the presence of amyloid in temporal artery biopsies were: age, hypertension, intralobar site of haemorrhage, APOE epsilon 2 and APOE epsilon 4 alleles.
Discussion:
Our findings of a higher frequency of amyloid deposition in temporal artery specimens in subjects with spontaneous intracerebral haemorrhage indicate a possible role of temporal artery as a possible diagnostic site of biopsy in subjects at high risk to develop intracranial haemorrhage related to Cerebral Amyloid Angiopath
Human physiologically based pharmacokinetic model for ACE inhibitors: ramipril and ramiprilat
BACKGROUND: The angiotensin-converting enzyme (ACE) inhibitors have complicated and poorly characterized pharmacokinetics. There are two binding sites per ACE (high affinity "C", lower affinity "N") that have sub-nanomolar affinities and dissociation rates of hours. Most inhibitors are given orally in a prodrug form that is systemically converted to the active form. This paper describes the first human physiologically based pharmacokinetic (PBPK) model of this drug class. METHODS: The model was applied to the experimental data of van Griensven et. al for the pharmacokinetics of ramiprilat and its prodrug ramipril. It describes the time course of the inhibition of the N and C ACE sites in plasma and the different tissues. The model includes: 1) two independent ACE binding sites; 2) non-equilibrium time dependent binding; 3) liver and kidney ramipril intracellular uptake, conversion to ramiprilat and extrusion from the cell; 4) intestinal ramipril absorption. The experimental in vitro ramiprilat/ACE binding kinetics at 4°C and 300 mM NaCl were assumed for most of the PBPK calculations. The model was incorporated into the freely distributed PBPK program PKQuest. RESULTS: The PBPK model provides an accurate description of the individual variation of the plasma ramipril and ramiprilat and the ramiprilat renal clearance following IV ramiprilat and IV and oral ramipril. Summary of model features: Less than 2% of total body ACE is in plasma; 35% of the oral dose is absorbed; 75% of the ramipril metabolism is hepatic and 25% of this is converted to systemic ramiprilat; 100% of renal ramipril metabolism is converted to systemic ramiprilat. The inhibition was long lasting, with 80% of the C site and 33% of the N site inhibited 24 hours following a 2.5 mg oral ramipril dose. The plasma ACE inhibition determined by the standard assay is significantly less than the true in vivo inhibition because of assay dilution. CONCLUSION: If the in vitro plasma binding kinetics of the ACE inhibitor for the two binding sites are known, a unique PBPK model description of the Griensven et. al. experimental data can be obtained
Analysis of symmetries in models of multi-strain infections
In mathematical studies of the dynamics of multi-strain diseases caused by antigenically diverse pathogens, there is a substantial interest in analytical insights. Using the example of a generic model of multi-strain diseases with cross-immunity between strains, we show that a significant understanding of the stability of steady states and possible dynamical behaviours can be achieved when the symmetry of interactions between strains is taken into account. Techniques of equivariant bifurcation theory allow one to identify the type of possible symmetry-breaking Hopf bifurcation, as well as to classify different periodic solutions in terms of their spatial and temporal symmetries. The approach is also illustrated on other models of multi-strain diseases, where the same methodology provides a systematic understanding of bifurcation scenarios and periodic behaviours. The results of the analysis are quite generic, and have wider implications for understanding the dynamics of a large class of models of multi-strain diseases
The effects of symmetry on the dynamics of antigenic variation
In the studies of dynamics of pathogens and their interactions with a host
immune system, an important role is played by the structure of antigenic
variants associated with a pathogen. Using the example of a model of antigenic
variation in malaria, we show how many of the observed dynamical regimes can be
explained in terms of the symmetry of interactions between different antigenic
variants. The results of this analysis are quite generic, and have wider
implications for understanding the dynamics of immune escape of other
parasites, as well as for the dynamics of multi-strain diseases.Comment: 21 pages, 4 figures; J. Math. Biol. (2012), Online Firs
Quantum Correlations in NMR systems
In conventional NMR experiments, the Zeeman energy gaps of the nuclear spin
ensembles are much lower than their thermal energies, and accordingly exhibit
tiny polarizations. Generally such low-purity quantum states are devoid of
quantum entanglement. However, there exist certain nonclassical correlations
which can be observed even in such systems. In this chapter, we discuss three
such quantum correlations, namely, quantum contextuality, Leggett-Garg temporal
correlations, and quantum discord. In each case, we provide a brief theoretical
background and then describe some results from NMR experiments.Comment: 21 pages, 7 figure
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