Does a too risk-averse approach to the implementation of new radiotherapy technologies delay their clinical use?

Radiotherapy is a generally safe treatment modality in practice; nevertheless, recent well-reported accidents also confirm its potential risks. However, this may obstruct or delay the introduction of new technologies and treatment strategies/techniques into clinical practice. Risks must be addressed and judged in a realistic context: risks must be assessed realistically. Introducing new technology may introduce new possibilities of errors. However, delaying the introduction of such new technology therefore means that patients are denied the potentially better treatment opportunities. Despite the difficulty in quantitatively assessing the risks on both sides of the possible choice of actions, including the "lost opportunity", the best estimates should be included in the overall risk-benefit and cost-benefit analysis. Radiotherapy requires a sufficiently high level of support for the safety, precision and accuracy required: radiotherapy development and implementation is exciting. However, it has been anxious with a constant awareness of the consequences of mistakes or misunderstandings. Recent history can be used to show that for introduction of advanced radiotherapy, the risk-averse medical physicist can act as an electrical fuse in a complex circuit. The lack of sufficient medical physics resource or expertise can short out this fuse and leave systems unsafe. Future technological developments will continue to present further safety and risk challenges. The important evolution of radiotherapy brings different management opinions and strategies. Advanced radiotherapy technologies can and should be safely implemented in as timely a manner as possible for the patient groups where clinical benefit is indicated.

In situ nanomechanical characterization of the early stages of swelling and degradation of a biodegradable polymer

The interactions of a biodegradable scaffold with cells or living tissues depend on the time-evolution of the nanoscale properties of the scaffold. We present an in situ quantitative study on the early-stage swelling and degradation of poly(lactic-co-glycolic acid) (PLGA). A novel metrology scheme based on force microscopy measurements of the patterns of PLGA nanostructures is developed to characterize the evolution of topography, volume and nanomechanical properties. The volume and nanoscale roughness show an oscillating behaviour during the first eight days of immersion; at a later stage, we observe a continuous decrease of the volume. The effective Young's modulus exhibits a monotonic decrease from an initial value of about 2.4 GPa down to 9 MPa at day 14. The oscillating behaviour of the volume before the onset of full degradation is explained by a coupled diffusion-swelling mechanism. The appearance of a second maximum in the volume evolution results from the competition between swelling and degradation.

Chemical composition and fermentation characteristics of sugar cane silage enriched with detoxified castor bean meal

This experiment was designed to evaluate the effects of the inclusion of detoxified castor bean meal (CM) content on the chemical-bromatological composition, as well as the fermentation characteristics and dry matter losses of sugarcane silage. The treatments consisted of four levels (0, 7, 14 and 21% natural matter) of addition of castor bean meal. The design was completely randomized, with five replicates. The material was ensiled in PVC silos of 50-cm in height and 10-cm in diameter, which were opened after 60 days. The density of fodder maintained in the silos was equal to 750kg of natural matter/m3. In order to quantify the gas and effluent losses, the silos were weighed at the beginning and at the end of the experiment. The addition of castor bean meal has increased the levels of DM and crude protein and reduced the levels of neutral detergent fiber, N-NH3, ethanol, and gas and effluent losses from silages, but did not affect pH values. During ensiling, alcoholic fermentation was controlled with the inclusion of the additive.

Low frequency ultrasound assisted sequential and co-precipitation syntheses of nanoporous RE (Gd and Sm) doped cerium oxide

Cerium oxide (CeO₂), Ce_0.9Gd_0.1O_1.95 and Ce_0.9Sm_0.1O_1.95 nanostructures were synthesized using 42 kHz ultrasound assisted sequential and co-precipitation techniques.

High-frequency stimulation of the hippocampus blocks fear learning sensitization and return of extinguished fear

Patients with post-traumatic stress disorder (PTSD) present hippocampal (HPC) dysfunction, which may facilitate fear-related phenomena such as fear learning sensitization (i.e. potentiation of fear acquisition by initial fear conditioning (FC1)) and fear return (i.e. reactivation of extinguished fear). Fear return is sensitive to HPC high-frequency stimulation (HFS) in rats. The goal of the present study was to examine whether fear learning sensitization is also sensitive to HPC HFS in rats. We found in control conditions that, after FC1 (with 15 shock administrations) and extinction, conditioning in a different context with one shock administration was potentiated (proactive effect) and associated with fear return in the initial context (retroactive effect). Both phenomena were prevented by HPC HFS applied before the second conditioning. We also found that the effect of HPC HFS on fear learning sensitization required initial extinction. These findings suggest a pivotal role of the HPC in preventing proactive and retroactive effects of successive fear conditionings. These data also support the concept that HPC deactivation may be involved in fear learning sensitization and fear return in PTSD patients.

Diets based on sugar cane treated with calcium oxide for lambs

This experiment was conducted to evaluate the intake, nutrient apparent digestibility and the effect of total collection days (two and four days) on apparent digestibility estimates for lambs fed diets containing sugar cane treated with calcium oxide (CaO). Eight Santa Inês castrated male lambs with a 16.6±1.8 kg body weight were used. The lambs were distributed in two 4×4 Latin squares, with four experimental periods of 14 d each. The animals were kept in 1.2 m² individual pens, and the intake and digestibility evaluations were performed during the last four days of each period. The diets were formulated to be isonitrogenous, containing 14% crude protein (CP), and presenting 70% sugar cane treated with 0, 0.75, 1.5 or 2.25% of CaO (as-fed basis), corrected with 1% urea, and 30% concentrate. The sugar cane with added CaO was chopped, treated, and offered to the animals after 24 h of storage. The sugar cane with CaO increased the DM, OM, CP, NDF, NDFap, TC, NFCap and TDN intake (kg/d), when compared to natural sugar cane, and produced the same intake expressed as a percentage of body weight (% BW). The NFCap digestibility of the CaO-treated sugar cane was inferior to the NFCap digestibility in natural sugar cane. There was a linear increase in the DM intake with the CaO-added sugar cane, but the DM and NDF digestibility and the TDN content decreased linearly. The chemical treatment of sugar cane with CaO increases the intake but does not improve the nutrient digestibility. Two days of total fecal collection were found to be sufficient to estimate the total apparent digestibility in lambs.

Prognostic usefulness of derived T2-weighted fetal magnetic resonance imaging measurements in congenital diaphragmatic hernia

OBJECTIVE

To determine the usefulness of various parameters based on T2-weighted fetal magnetic resonance (MR) imaging measurements of the uninvolved lung for the neonatal prognosis of congenital diaphragmatic hernia (CDH).

MATERIAL AND METHODS

We used ultrasonography and MR imaging to study 28 fetuses with CDH. We retrospectively analyzed a) on fetal ultrasonography, the observed-to-expected lung to head ratio (O/E LHR) and the position of the liver, and b) on fetal MR imaging, the lung-liver signal ratio (LLSR) and the lungcerebrospinal fluid ratio (L/CSF SR). To determine the prognostic value of these parameters, we compared them with the following postnatal parameters: survival, pulmonary hypertension, need for oxygen supplementation, and need for extracorporeal membrane oxygenation.

RESULTS

We found significant differences between O/E LHR and the need for postnatal extracorporeal membrane oxygenation (P=.033) and postnatal survival (P=.01). We also found significant differences in LLSR between fetuses that survived more than 45 days and those that died within 45 days (1.91 vs. 2.56; P=.039).

CONCLUSIONS

In fetuses with CDH, the LLSR correlates with postnatal survival and can potentially be used as a prognostic parameter in CDH.