273 research outputs found
The identity of Rana margaritifera Laurenti, 1768 (Anura, Bufonidae)
Rana margaritifera was described by Laurenti in 1768 and currently is associated to the genus Rhinella, under the combination Rhinella margaritifera. Currently, the R. margaritifera species group consists of 16 recognized species. Furthermore, many additional species have been suggested to exist in this group which highlights the ambiguity surrounding the identity of Rhinella margaritifera and impend further description of the species in this group. After an exhaustive bibliographic review, we concluded that the recent designation of a lectotype for R. margaritifera is invalid according with Art. 73, ICZN, 1999. Herein, we designate and provide the description of a neotype for Rana margaritifera Laurenti, 1768.Fil: Lavilla, Esteban Orlando. Fundación Miguel Lillo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán; ArgentinaFil: Caramaschi, Ulisses. Universidade Federal do Rio de Janeiro; BrasilFil: Langone, Jose A.. Museo Nacional de Historia Natural. Departamento de Herpetología; UruguayFil: Pombal, Jose P.. Universidade Federal do Rio de Janeiro; BrasilFil: de Sá, Rafael O.. University of Richmond. Department of Biology; Estados Unido
Polarized X-ray-emission Studies of Methyl Chloride and the Chlorofluoromethanes
A new technique sensitive to molecular orientation and geometry, and based on measuring the polarization of x-ray emission, has been applied to the Cl-containing molecules methyl chloride (CH3Cl) and the chlorofluoromethanes (CF3Cl, CF2Cl2, and CFCl3) in the gas phase. Upon selective excitation using monochromatic synchrotron radiation in the Cl K-edge (Cl 1s) near-threshold region, polarization-selective x-ray emission studies reveal highly polarized molecular valence x-ray fluorescence for all four molecules. The degree and the orientation of the polarized emission are observed to be sensitive to the incident excitation energy near the Cl Kedge. In some cases, the polarization direction for x-ray emission reverses for small changes in incident excitation energy (a few eV). It is shown that the polarized x-ray emission technique can be used to infer, directly from experiment, symmetries of occupied and unoccupied valence molecular orbitals, an- isotropies in absorption and emission, and orientational and geometrical information. It is suggested that the x-ray polarized-fluorescence phenomenon, reported here for simple molecules, can be used as a new approach to study more complicated systems in a variety of environments
The Identity of \u3cem\u3eRana margaritifera\u3c/em\u3e Laurenti, 1768 (Anura, Bufonidae)
Rana margaritifera was described by Laurenti in 1768 and currently is associated to the genus Rhinella, under the combination Rhinella margaritifera. Currently, the R. margaritifera species group consists of 16 recognized species. Further-more, many additional species have been suggested to exist in this group which highlights the ambiguity surrounding the identity of Rhinella margaritifera and impend further description of the species in this group. After an exhaustive bibliographic review, we concluded that the recent designation of a lectotype for R. margaritifera is invalid according with Art. 73, ICZN, 1999. Herein, we designate and provide the description of a neotype for Rana margaritifera Laurenti, 1768
Molecular-orbital Studies Via Satellite-free X-ray Fluorescence: Cl-K Absorption and K–Valence-level Emission Spectra of Chlorofluoromethanes
X-ray absorption and emission measurements in the vicinity of the chlorine K edge of the three chlorofluoromethanes have been made using monochromatic synchrotron radiation as the source of excitation. By selectively tuning the incident radiation to just above the Cl 1s single-electron ionization threshold for each molecule, less complex x-ray-emission spectra are obtained. This reduction in complexity is attributed to the elimination of multielectron transitions in the Cl K shell, which commonly produce satellite features in x-ray emission. The resulting satellite-free x-ray-emission spectra exhibit peaks due only to electrons in valence molecular orbitals filling a single Cl 1s vacancy. These simplified emission spectra and the associated x-ray absorption spectra are modeled using straightforward procedures and compared with semiempirical ground-state molecular-orbital calculations. Good agreement is observed between the present experimental and theoretical results for valence-orbital energies and those obtained from ultraviolet photoemission, and between relative radiative yields determined both experimentally and theoretically in this work
Identification of novel plant cysteine oxidase inhibitors from a yeast chemical genetic screen
Hypoxic responses in plants involve Plant Cysteine Oxidases (PCOs). They catalyze the N-terminal cysteine oxidation of Ethylene Response Factors VII (ERF-VII) in an oxygen-dependent manner, leading to their degradation via the cysteine N-degron pathway (Cys-NDP) in normoxia. In hypoxia, PCO activity drops, leading to the stabilization of ERF-VIIs and subsequent hypoxic gene upregulation. Thus far, no chemicals have been described to specifically inhibit PCO enzymes. In this work, we devised an in vivo pipeline to discover Cys-NDP effector molecules. Budding yeast expressing AtPCO4 and plant-based ERF-VII reporters was deployed to screen a library of natural-like chemical scaffolds and was further combined with an Arabidopsis Cys-NDP reporter line. This strategy allowed us to identify three PCO inhibitors, two of which were shown to affect PCO activity in vitro. Application of these molecules to Arabidopsis seedlings led to an increase in ERF-VII stability, induction of anaerobic gene expression, and improvement of tolerance to anoxia. By combining a high-throughput heterologous platform and the plant model Arabidopsis, our synthetic pipeline provides a versatile system to study how the Cys-NDP is modulated. Its first application here led to the discovery of at least two hypoxia-mimicking molecules with the potential to impact plant tolerance to low oxygen stress
Karnofsky performance score in acute renal failure as a predictor of short-term survival
Karnofsky Performance Scale Index (KPS) is a measure of functional
status that allows patients to be classified according to their functional
impairment. We aim to assess if the prior KPS may predict the risk of death among
patients with acute renal failure (ARF). METHODS: A cohort of 668 consecutive
patients who had been admitted in an university-affiliated hospital between June
2000 and June 2006, and had been diagnosed with ARF, were studied. Three hundred
and eighty-six patients with ARF who matched at least one of the RIFLE (Risk,
Injury, Failure, Loss and End stage) criteria on increased serum creatinine were
included for subsequent analysis. The group was divided into four categories,
according to different Karnofsky scores measured by a nephrologist (>or=80, 70,
60 and <or=50). We used an adjusted logistic regression model to assess the
relationship between the Karnofky score and mortality. RESULTS: A significant
risk of in-hospital mortality within 90 days was observed when the other groups
were compared with the >or=80 Karnofsky group. Adjusted odds ratios were 8.87
(95% confidence interval (CI) 3.03-25.99), 6.78 (95% CI 2.61-17.58) and 2.83 (95%
CI 1.04-7.68), for Karnofsky groups of <or=50, 60 and 70, respectively. An
adjusted odds ratio of 1.75 (95% CI 1.37-2.23) was observed for every 10 point
decrease in KPS score. CONCLUSION: Functional status as indicated by the KPS is
an independent predictor of death in this cohort of patients with ARF. Patients
who presented lower scores had increased mortality rate
Evaluation of the prognostic value of the risk, injury, failure, loss and end-stage renal failure (RIFLE) criteria for acute kidney injury
AIM: The experts have argued about the use of the risk, injury, failure, loss and end-stage renal failure (RIFLE) criteria as a prognosis scoring system. We examined the association between in-hospital mortality and the RIFLE criteria, and discussed its accuracy as a prognosis factor.
METHODS: In this prospective study, we analysed the data gathered from a cohort of 956 patients admitted in a Spanish tertiary hospital between January 1998 and April 2006. Hazard ratios for mortality, and survival curves within 60 days were calculated. Discrimination and calibration of the model were also assessed.
RESULTS: Excluding 53 patients, 903 patients were finally analysed. We classified them into groups according to the maximum RIFLE class reached during their admission. The RIFLE class was assessed by the glomerular filtration rate criterion. We found an increase in the in-hospital mortality risk. Cox proportional hazard models showed that RIFLE classes risk, injury, and failure were significant predictive factors (hazard ratios were 2.77, 3.23 and 3.52, respectively; P for trend was 0.005). The multivariate analyses from the cross-classification of the participants according to Liano score values (severity of illness) and RIFLE classes showed additive effects of the exposures on in-hospital mortality.
CONCLUSION: In this population, the risk of in-hospital mortality during the acute kidney injury (AKI) episode was positively associated with RIFLE classes. We showed that the RIFLE classification system had discriminative power in predicting hospital mortality within 60 days in AKI patients, but not better than a specific AKI predictive model. However, a combined use of both may give a more robust prognosis system
Serum C-reactive protein on the prognosis of oncology patients with acute renal failure: an observational cohort study
We undertook this study to evaluate the significance of the C-reactive protein level (CRP) as a prognostic factor in oncology patients with acute renal failure (ARF) during nephrology consultation. METHODS: The study was
comprised of a cohort of 375 consecutive oncology patients who had been admitted
to a university-affiliated hospital between March 1998 and April 2006 and had
been diagnosed with ARF. One hundred and fifty nine patients with ARF who matched
at least one of the RIFLE criteria on increased serum creatinine were included
for subsequent analysis. We used a Cox proportional hazard model. RESULTS:
Clinical pathological variables were compared among patients with serum CRP
levels > or =8 mg/dL (exposed group; cut-off point: median) and patients with
serum CRP level <8 mg/dL (control group). In-hospital mortality rates associated
with CRP levels were 53.8% for > or =8 mg/dL and 21.5% for <8 mg/dL (p <0.001).
After adjusted analysis, the presence of a CRP level > or =8 mg/dL was
significantly associated with an increased in-hospital mortality (HR 2.10; 95%
CI: 1.17-3.78) than in those patients with similar Liano scoring, the same RIFLE
classes, and the same treatment for ARF. In addition, each increment of 1 mg/dL
of serum CRP was associated with an adjusted 4% increment of in-hospital
mortality (HR 1.04, 95% CI: 1.01-1.06). CONCLUSIONS: CRP levels at nephrology
consultation were an independent predictor of death in this cohort of oncology
patients with ARF. Patients with levels > or =8 mg/dL may be considered at higher
risk of death
Mercury Levels in Locally Manufactured Mexican Skin-Lightening Creams
Mercury is considered one of the most toxic elements for plants and animals. Nevertheless, in the Middle East, Asia and Latin America, whitening creams containing mercury are being manufactured and purchased, despite their obvious health risks. Due to the mass distribution of these products, this can be considered a global public health issue. In Mexico, these products are widely available in pharmacies, beauty aid and health stores. They are used for their skin lightening effects. The aim of this work was to analyze the mercury content in some cosmetic whitening creams using the cold vapor technique coupled with atomic absorption spectrometry (CV-AAS). A total of 16 skin-lightening creams from the local market were investigated. No warning information was noted on the packaging. In 10 of the samples, no mercury was detected. The mercury content in six of the samples varied between 878 and 36,000 ppm, despite the fact that the U.S. Food and Drug Administration (FDA) has determined that the limit for mercury in creams should be less than 1 ppm. Skin creams containing mercury are still available and commonly used in Mexico and many developing countries, and their contents are poorly controlled
Ejercicio físico e insuficiencia renal crónica
Los pacientes con insuficiencia renal crónica tienen una menor capacidad física y un conjunto de alteraciones metabólicas, cardiovasculares y psicológicas. Los programas de ejercicio físico, no sólo, han demostrado ser efectivos en mejorar la capacidad física de los pacientes en hemodiálisis sino que permiten un mejor control de la hipertensión, metabolismo lipídico y glucídico, de la anemia y la depresión.
Queda todavía por ser determinado si los programas de ejercicio pueden, en última instancia, reducir la morbilidad, prolongar la supervivencia y mejorar la calidad de vida de estos pacientes. De todas maneras, el ejercicio físico debe ser considerado como un importante aspecto en la rehabilitación de estos pacientes
- …