67 research outputs found

    Current role of surgery in small cell lung carcinoma

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    Small cell lung carcinoma represents 15–20% of lung cancer. Is is characterized by rapid growth and early disseminated disease with poor outcome. For many years surgery was considered a contraindication in Small Cell Lung Cancer (SCLC) since radiotherapy and chemoradiotherapy were found to be more efficient in the management of these patients. Never the less some surgeons continue to be in favor of surgery as part of a combined modality treatment in patients with SCLC. The revaluation of the role of surgery in this group of patients is based on clinical data indicating a much better prognosis in selected patients with limited disease (T1-2, N0, M0), the high rate of local recurrence after chemoradiotherapy with surgery considered eventually more efficient in the local control of the disease and the fact that surgery is the most accurate tool to access the response to chemotherapy, identify carcinoids misdiagnosed as SCLC and treat the Non Small Cell Lung Cancer component of mixed tumors. Performing surgery for local disease SCLC requires a complete preoperative assessment to exclude the presence of nodal involvement. In stage I surgery must always be followed by adjuvant chemotherapy, while in stage II and III surgery must be planned only in the context of clinical trials and after a pathologic response to induction chemoradiotherapy has been confirmed. Prophylactic cranial irradiation should be used to reduce the incidence of brain metastasi

    Synthetic Biology of Proteins: Tuning GFPs Folding and Stability with Fluoroproline

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    Proline residues affect protein folding and stability via cis/trans isomerization of peptide bonds and by the C(gamma)-exo or -endo puckering of their pyrrolidine rings. Peptide bond conformation as well as puckering propensity can be manipulated by proper choice of ring substituents, e.g. C(gamma)-fluorination. Synthetic chemistry has routinely exploited ring-substituted proline analogs in order to change, modulate or control folding and stability of peptides.In order to transmit this synthetic strategy to complex proteins, the ten proline residues of enhanced green fluorescent protein (EGFP) were globally replaced by (4R)- and (4S)-fluoroprolines (FPro). By this approach, we expected to affect the cis/trans peptidyl-proline bond isomerization and pyrrolidine ring puckering, which are responsible for the slow folding of this protein. Expression of both protein variants occurred at levels comparable to the parent protein, but the (4R)-FPro-EGFP resulted in irreversibly unfolded inclusion bodies, whereas the (4S)-FPro-EGFP led to a soluble fluorescent protein. Upon thermal denaturation, refolding of this variant occurs at significantly higher rates than the parent EGFP. Comparative inspection of the X-ray structures of EGFP and (4S)-FPro-EGFP allowed to correlate the significantly improved refolding with the C(gamma)-endo puckering of the pyrrolidine rings, which is favored by 4S-fluorination, and to lesser extents with the cis/trans isomerization of the prolines.We discovered that the folding rates and stability of GFP are affected to a lesser extent by cis/trans isomerization of the proline bonds than by the puckering of pyrrolidine rings. In the C(gamma)-endo conformation the fluorine atoms are positioned in the structural context of the GFP such that a network of favorable local interactions is established. From these results the combined use of synthetic amino acids along with detailed structural knowledge and existing protein engineering methods can be envisioned as a promising strategy for the design of complex tailor-made proteins and even cellular structures of superior properties compared to the native forms

    Seasonal differences of corticosterone metabolite concentrations and parasite burden in northern bald ibis (Geronticus eremita): The role of affiliative interactions

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    The reproductive season is energetically costly as revealed by elevated glucocorticoid concentrations, constrained immune functions and an increased risk of infections. Social allies and affiliative interactions may buffer physiological stress responses and thereby alleviate associated effects. In the present study, we investigated the seasonal differences of immune reactive corticosterone metabolite concentrations, endoparasite burden (nematode eggs and coccidian oocysts) and affiliative interactions in northern bald ibis (Geronticus eremita), a critically endangered bird. In total, 43 individually marked focal animals from a freeranging colony were investigated. The analyses included a description of initiated and received affiliative interactions, pair bond status as well as seasonal patterns of hormone and endoparasite levels. During the reproductive season, droppings contained parasite eggs more often and corticosterone metabolite levels were higher as compared to the period after reproduction. The excretion rate of endoparasite products was lower in paired individuals than in unpaired ones, but paired animals exhibited higher corticosterone metabolite concentrations than unpaired individuals. Furthermore, paired individuals initiated affiliative behaviour more frequently than unpaired ones. This suggests that the reproductive season influences the excretion patterns of endoparasite products and corticosterone metabolites and that affiliative interactions between pair partners may positively affect endoparasite burden during periods of elevated glucocorticoid levels. Being embedded in a pair bond may have a positive impact on individual immune system and parasite resistance

    Multi-messenger observations of a binary neutron star merger

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    On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

    First report of Amblyomma dubitatum (Acari: Ixodidae) parasitizing the crab-eating raccoon, Procyon cancrivorus (Carnivora: Procyonidae)

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    In October 2015, a tick nymph was collected from a male Procyon cancrivorus found dead at the roadside of the National Road 119 near Mercedes city, Corrientes province, Argentina. The nymph collected was morphologically and molecularly identified as Amblyomma dubitatum and it was found infected with the alpha-proteobacterium Rickettsia bellii. To the best of our knowledge, this report constitutes the first record of the A. dubitatum - P. cancrivorus association. RESUMEN. Primer reporte de Amblyomma dubitatum (Acari: Ixodidae) parasitando al aguará popé, Procyon cancrivorus (Carnivora: Procyonidae). En octubre de 2015, una ninfa de garrapata fue colectada sobre un ejemplar macho de Procyon cancrivorus hallado muerto a la vera de la Ruta Nacional 119 en las cercanías de la ciudad de Mercedes, provincia de Corrientes, Argentina. La ninfa colectada fue identificada morfológica y molecularmente como Amblyomma dubitatum, y la misma se encontró infectada con la alfa-proteobacteria Rickettsia bellii. Este reporte constituye el primer registro de la asociación A. dubitatum P. cancrivorus
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