Hydration-dependent dynamics of human telomeric oligonucleotides in the picosecond timescale: a neutron scattering study.

The dynamics of the human oligonucleotide AG3(T2AG3)3 has been investigated by incoherent neutron scattering in the sub-nanosecond timescale. A hydration-dependent dynamical activation of thermal fluctuations in weakly hydrated samples was found, similar to that of protein powders. The amplitudes of such thermal fluctuations were evaluated in two different exchanged wave-vector ranges, so as to single out the different contributions from intra- and inter-nucleotide dynamics. The activation energy was calculated from the temperature-dependent characteristic times of the corresponding dynamical processes. The trends of both amplitudes and activation energies support a picture where oligonucleotides possess a larger conformational flexibility than long DNA sequences. This additional flexibility, which likely results from a significant relative chain-end contribution to the average chain dynamics, could be related to the strong structural polymorphism of the investigated oligonucleotides.

Fraud-proof methylcellulose-based fish freshness indicator: Reversibility in halochromic sensing of basic volatiles is tailored by ionic strength.

Food from animal sources (e.g., fish) represents the food group most likely to disseminate diseases to humans. To prevent food contamination and foodborne illnesses, intelligent packaging has been developed to monitor fish freshness by real-time tracking their physicochemical attributes and informing consumers about their conservation state. In this context, we investigated the influence of ionic strength (IS) provided by CaCl2 on the chromatic response of anthocyanin açai extracts incorporated into methylcellulose (MC) within hydrocolloid-based colorimetric sensors for monitoring the freshness of Lambari fish. The color sensitivity of the sensors was modulated by IS in the presence of NH3 volatile and/or TVB-N. Increasing IS led to a plasticizing effect in the MC matrix, which influenced the chromatic properties of anthocyanin in the presence of NH3 and/or TVB-N. The perception of distinct colors by untrained eyes improved from 10 min with the control sensor to 2.5 min for sensors with IS >50 mM. Adjusting the IS to 500 mM with LiCl, CaCl2, or MgCl2 resulted in gray-green, blue, or moss-green colors, respectively, diverging from the control sensor's color (pink and gray) after 10 min of ammonia exposure, confirming salt-induced copigmentation. Color irreversibility in the sensors was achieved when the IS exceeded 250 mM. Through principal component analysis, we statistically validate the efficacy of the sensor in assessing the freshness of Lambari fish. The sensor maintained its color-change capability even after 60 d of storage and was able to classify Lambari fish freshness according to Brazilian and European standards. This study elucidates the interrelation between the structures and properties of natural compounds such as MC, anthocyanin, and CaCl2, providing a method to control the chromatic properties of sensors intended to monitor food quality, safety, and shelf-life.

AZOOR with unilateral disc edema: An atypical case report.

Acute zonal occult outer retinopathy (AZOOR) diagnosis is challenging and frequently delayed. Atypical findings were described, nevertheless optic disc edema has not been consistently reported. In this study we pretend to describe a challenging diagnosis of AZOOR. In our case, a 19-year-old female presented painless vision loss in her right eye for 2 weeks. Fundus examination revealed optic disc hyperaemic edema and the visual field (VF) an enlarged blind spot. Non-infectious optic neuritis was assumed and intravenous corticotherapy administered. Four months later, VA had improved, but a VF defect persisted. Funduscopic examination showed mild peripapillary atrophy and autofluorescence zonal hyperautofluorescence around optic disc. Optical coherence tomography demonstrated diffuse loss of outer retinal layers and electroretinogram weakened signal at the corresponding region. In conclusion, unilateral optic disc edema, generally not associated with AZOOR typical presentation, hamper an early diagnosis and expresses this case relevance.

Sweet neutron crystallography.

Extremely sweet proteins isolated from tropical fruit extracts are promising healthy alternatives to sugar and synthetic sweeteners. Sweetness and taste in general are, however, still poorly understood. The engineering of stable sweet proteins with tailored properties is made difficult by the lack of supporting high-resolution structural data. Experimental information on charge distribution, protonation states and solvent structure are vital for an understanding of the mechanism through which sweet proteins interact with taste receptors. Neutron studies of the crystal structures of sweet proteins allow a detailed study of these biophysical properties, as illustrated by a neutron study on the native protein thaumatin in which deuterium labelling was used to improve data quality.

Insights into the antiviral activity of phospholipases A2 (PLA2s) from snake venoms.

Viruses are associated with several human diseases that infect a large number of individuals, hence directly affecting global health and economy. Owing to the lack of efficient vaccines, antiviral therapy and emerging resistance strains, many viruses are considered as a potential threat to public health. Therefore, researches have been developed to identify new drug candidates for future treatments. Among them, antiviral research based on natural molecules is a promising approach. Phospholipases A2 (PLA2s) isolated from snake venom have shown significant antiviral activity against some viruses such as Dengue virus, Human Immunodeficiency virus, Hepatitis C virus and Yellow fever virus, and have emerged as an attractive alternative strategy for the development of novel antiviral therapy. Thus, this review provides an overview of remarkable findings involving PLA2s from snake venom that possess antiviral activity, and discusses the mechanisms of action mediated by PLA2s against different stages of virus replication cycle. Additionally, molecular docking simulations were performed by interacting between phospholipids from Dengue virus envelope and PLA2s from Bothrops asper snake venom. Studies on snake venom PLA2s highlight the potential use of these proteins for the development of broad-spectrum antiviral drugs.

New sources and instrumentation for neutrons in biology.

Neutron radiation offers significant advantages for the study of biological molecular structure and dynamics. A broad and significant effort towards instrumental and methodological development to facilitate biology experiments at neutron sources worldwide is reviewed.

A novel semi-robotized device for high-precision 18F-FDG-guided breast cancer biopsy.

PURPOSE: To assess the 3D geometric sampling accuracy of a new PET-guided system for breast cancer biopsy (BCB) from areas within the tumour with high 18F-FDG uptake. MATERIALS AND METHODS: In the context of the European Union project MammoCare, a prototype semi-robotic stereotactic prototype BCB-device was incorporated into a dedicated high resolution PET-detector for breast imaging. The system consists of 2 stacked rings, each containing 12 plane detectors, forming a dodecagon with a 186mm aperture for 3D reconstruction (1mm3 voxel). A vacuum-assisted biopsy needle attached to a robot-controlled arm was used. To test the accuracy of needle placement, the needle tip was labelled with 18F-FDG and positioned at 78 target coordinates distributed over a 35mm×24mm×28mm volume within the PET-detector field-of-view. At each position images were acquired from which the needle positioning accuracy was calculated. Additionally, phantom-based biopsy proofs, as well as MammoCare images of 5 breast cancer patients, were evaluated for the 3D automated locating of 18F-FDG uptake areas within the tumour. RESULTS: Needle positioning tests revealed an average accuracy of 0.5mm (range 0-1mm), 0.6mm (range 0-2mm), and 0.4mm (range 0-2mm) for the x/y/z-axes, respectively. Furthermore, the MammoCare system was able to visualize and locate small (<10mm) regions with high 18F-FDG uptake within the tumour suitable for PET-guided biopsy after being located by the 3D automated application. CONCLUSIONS: Accuracy testing demonstrated high-precision of this semi-automatic 3D PET-guided system for breast cancer core needle biopsy. Its clinical feasibility evaluation in breast cancer patients scheduled for neo-adjuvant chemotherapy will follow.

PET/CT with 18F-FDG predicts short-term outcome in stage II/III breast cancer patients upstaged to N2/3 nodal disease.

INTRODUCTION: 18F-FDG PET/CT has high positive predictive value for the detection of avid lymph node metastases in breast cancer patients. We analysed the effect of upstaging lymph nodes by PET/CT on short-term outcome in stage II/III breast cancer patients. PATIENTS AND METHODS: A total of 278 stage II/III primary breast cancer patients (mean age 48.9 years, range 19-75 years) were re-staged with 18F-FDG PET/CT before start of pre-operative systemic treatment (PST). Patients were divided in three groups based on risk for local recurrence: a low - (T2N0), intermediate - (T0-2N1 and T3N0) and a high-risk group (T0-3N2-3, T3N1 and T4). Within these groups we looked at local recurrence-free survival (LRFS), recurrence-free survival (RFS) and overall survival (OS) within the first 3 years of follow-up. RESULTS: With a median follow-up (FU) of 50 months the RFS, LRFS and OS were 87%, 88% and 92% respectively for the whole group. PET/CT upstaged 43 patients from the low- and intermediate risk group to the high-risk group, based on detection of ≥4 avid axillary nodes or occult N2/3-disease. Patients upstaged with PET/CT had more events for all three analyses compared to the original risk groups, which resulted in a significantly worse RFS (69.8%; p = 0.03) a nearly significantly worse LRFS (p = 0.052) and no effect in OS (p = 0.433). DISCUSSION: Additional PET/CT staging allows breast cancer patients to be treated according to the true stage, still stage II/III breast cancer patients upstaged to N2/3 by PET/CT have worse short-term outcome, despite adjustment of treatment, than patients staged high-risk with conventional imaging.

Substrate specificity and subsite mobility in T. aurantiacus xylanase 10A.

The substrate specificity of Thermoascus aurantiacus xylanase 10A (TAX) has been investigated both biochemically and structurally. High resolution crystallographic analyses at 291 K and 100 K of TAX complexes with xylobiose show that the ligand is in its alpha anomeric conformation and provide a rationale for specificity on p-nitrophenyl glycosides at the -1 and -2 subsites. Trp 275, which is disordered in uncomplexed structures, is stabilised by its interaction with xylobiose. Two structural subsets in family 10 are identified, which differ by the presence or absence of a short helical stretch in the eighth betaalpha-loop of the TIM barrel, the loop bearing Trp 275. This structural difference is discussed in the context of Trp 275 mobility and xylanase function.

[Botulinum toxin the treatment of spasmodic torticollis: a meta-analysis]. / Toxina botulínica no tratamento do torcicolo espasmódico: uma meta-análise.

The authors made a meta-analysis of the results of botulinum toxin injection for the treatment of spasmodic torticollis. They concluded that botulinum toxin is effective for the treatment of cervical dystonia.

AZOOR con edema discal unilateral: informe de un caso atípico / AZOOR with unilateral disc edema: An atypical case report

El diagnóstico de retinopatía aguda zonal oculta externa (AZOOR) se presenta como un desafío en la práctica del oftalmólogo. En esta enfermedad fueron descritos varios hallazgos atípicos, pero el edema del disco óptico es raro. Pretendemos describir un diagnóstico desafiador de AZOOR. Presentamos el caso de una mujer de 19 años con pérdida de visión del ojo derecho, sin dolor, con 2 semanas de evolución. El fondo de ojo presentaba edema con hiperemia del disco óptico y la campimetría demostraba una mancha ciega aumentada. Se ha considerado como diagnóstico neuritis óptica, sin causa infecciosa, por lo que ha realizado tratamiento con corticoide. Después de 4 meses, la agudeza visual había mejorado, pero persistían las alteraciones en la campimetría con hiperautofluorescencia alrededor del disco óptico. La tomografía óptica de coherencia demostró pérdida generalizada de las capas externas de la retina y disminución de la reflectancia de la región correspondiente. Se concluye que el edema de la papila no es un hallazgo frecuente de AZOOR, por lo que representa una enfermedad de difícil diagnóstico (AU)

Acute zonal occult outer retinopathy (AZOOR) diagnosis is challenging and frequently delayed. Atypical findings were described, nevertheless optic disc edema has not been consistently reported. In this study we pretend to describe a challenging diagnosis of AZOOR. In our case, a 19-year-old female presented painless vision loss in her right eye for 2 weeks. Fundus examination revealed optic disc hyperaemic edema and the visual field (VF) an enlarged blind spot. Non-infectious optic neuritis was assumed and intravenous corticotherapy administered. Four months later, VA had improved, but a VF defect persisted. Funduscopic examination showed mild peripapillary atrophy and autofluorescence zonal hyperautofluorescence around optic disc. Optical coherence tomography demonstrated diffuse loss of outer retinal layers and electroretinogram weakened signal at the corresponding region. In conclusion, unilateral optic disc edema, generally not associated with AZOOR typical presentation, hamper an early diagnosis and expresses this case relevance (AU)

Urological leaks after pelvic exenterations comparing formation of colonic and ileal conduits.

BACKGROUND: The aim of this study was to assess possible risk factors for urinary leakage of a newly formed urinary conduit after a partial or total pelvic exenteration. METHODS: An analysis was conducted from prospectively collected data of patients who underwent a pelvic exenteration with conduit formation for advanced and recurrent pelvic cancer. RESULTS: Of 232 patients undergoing a pelvic exenteration, 74 (32%) had a conduit formed. Of these, 47 (64%) had an ileal conduit compared with 27 (36%) a colonic conduit. Twelve (16%) patients developed a leak, of which nine occurred within the first month. Factors associated with a conduit leak included involvement of R2 surgical margins (43%), the magnitude of the exenteration and a current cardiovascular medical history (27%). Leaks were not found to be associated with either radiotherapy or chemotherapy. The 30-day leak rate for ileal conduits was 17% (8/47) and 4% (1/27) for colonic conduits with enterocutaneous fistula only occurring in the ileal conduit group (2/47). Fistula, drained collections and sepsis occurred in 40% of ileal and 19% of colonic conduits (p < 0.01). Patients with a conduit leak had a longer length of stay (59 versus 23 days, p < 0.001). CONCLUSIONS: Urine leaks after conduit formation in association with exenterations are relatively common with a prolonged length of hospital stay. Positive surgical margins and exenterations involving all four quadrants of the pelvis were associated with higher leak rates. There was no evidence of a difference between ileal and colonic conduits and number of leaks. However colonic conduits had less total complications including sepsis, leak and pelvic collections with comparatively no complications of a small bowel fistula.