Thermal tolerance does not explain the altitudinal segregation of lowland and alpine aquatic insects.

Elevation gradients provide powerful study systems for examining the influence of environmental filters in shaping species assemblages. High-mountain habitats host specific high-elevation assemblages, often comprising specialist species adapted to endure pronounced abiotic stress, while such harsh conditions prevent lowland species from colonizing or establishing. While thermal tolerance may drive the altitudinal segregation of ectotherms, its role in structuring aquatic insect communities remains poorly explored. This study investigates the role of thermal physiology in shaping the current distribution of high-mountain diving beetles from the Sierra Nevada Iberian mountain range and closely related lowland species. Cold tolerance of five species from each altitudinal zone was measured estimating the supercooling point (SCP), lower lethal temperature (LLT) and tolerance to ice enclosure, while heat tolerance was assessed from the heat coma temperature (HCT). Alpine species exhibited wider fundamental thermal niches than lowland species, likely associated with the broader range of climatic conditions in high-mountain areas. Cold tolerance did not seem to prevent lowland species from colonizing higher elevations, as most studied species were moderately freeze-tolerant. Therefore, fundamental thermal niches seem not to fully explain species segregation along elevation gradients, suggesting that other thermal tolerance traits, environmental factors, and biotic interactions may also play important roles.

The hip fracture surgery in elderly patients (HIPELD) study to evaluate xenon anaesthesia for the prevention of postoperative delirium: a multicentre, randomized clinical trial.

BACKGROUND: Postoperative delirium occurs frequently in elderly hip fracture surgery patients and is associated with poorer overall outcomes. Because xenon anaesthesia has neuroprotective properties, we evaluated its effect on the incidence of delirium and other outcomes after hip fracture surgery. METHODS: This was a phase II, multicentre, randomized, double-blind, parallel-group, controlled clinical trial conducted in hospitals in six European countries (September 2010 to October 2014). Elderly (≥75yr-old) and mentally functional hip fracture patients were randomly assigned 1:1 to receive either xenon- or sevoflurane-based general anaesthesia during surgery. The primary outcome was postoperative delirium diagnosed through postoperative day 4. Secondary outcomes were delirium diagnosed anytime after surgery, postoperative sequential organ failure assessment (SOFA) scores, and adverse events (AEs). RESULTS: Of 256 enrolled patients, 124 were treated with xenon and 132 with sevoflurane. The incidence of delirium with xenon (9.7% [95% CI: 4.5 -14.9]) or with sevoflurane (13.6% [95% CI: 7.8 -19.5]) were not significantly different (P=0.33). Overall SOFA scores were significantly lower with xenon (least-squares mean difference: -0.33 [95% CI: -0.60 to -0.06]; P=0.017). For xenon and sevoflurane, the incidence of serious AEs and fatal AEs was 8.0% vs 15.9% (P=0.05) and 0% vs 3.8% (P=0.06), respectively. CONCLUSIONS: Xenon anaesthesia did not significantly reduce the incidence of postoperative delirium after hip fracture surgery. Nevertheless, exploratory observations concerning postoperative SOFA-scores, serious AEs, and deaths warrant further study of the potential benefits of xenon anaesthesia in elderly hip fracture surgery patients. CLINICAL TRIAL REGISTRATION: EudraCT 2009-017153-35; ClinicalTrials.gov NCT01199276.

Metabolic and reproductive plasticity of core and marginal populations of the eurythermic saline water bug Sigara selecta (Hemiptera: Corixidae) in a climate change context.

Ongoing climate change is driving dramatic range shifts in diverse taxa worldwide, and species responses to global change are likely to be determined largely by population responses at geographical range margins. Here we investigate the metabolic and reproductive plasticity in response to water temperature and salinity variation of two populations of the eurythermic saline water bug Sigara selecta: one population located close to the northern edge of its distribution, in a relatively cold, thermally stable region (SE England - 'marginal'), and one close to the range centre, in a warmer and more thermally variable Mediterranean climate (SE Spain - 'core'). We compared metabolic and oviposition rates and egg size, following exposure to one of four different combinations of temperature (15 and 25°C) and salinity (10 and 35gL-1). Oviposition rate was significantly higher in the marginal population, although eggs laid were smaller overall. No significant differences in oxygen consumption rates were found between core and marginal populations, although the marginal population showed higher levels of plasticity in both metabolic and reproductive traits. Our results suggest that population-specific responses to environmental change are complex and may be mediated by differences in phenotypic plasticity. In S. selecta, the higher plasticity of the marginal population may facilitate both its persistence in current habitats and northward expansion with future climatic warming. The less plastic core population may be able to buffer current environmental variability with minor changes in metabolism and fecundity, but could be prone to extinction if temperature and salinity changes exceed physiological tolerance limits in the future.

Hipertensión endocraneal asociada a la sedación con sevoflurano mediante el dispositivo AnaConDa ®en un paciente con traumatismo craneoencefálico severo / Intracranial hypertension related to sedation with sevoflurane using the AnaConDa ® device in a patient with severe traumatic brain injury

La sedación en los pacientes neurocríticos es difícil, debido a que ningún fármaco cumple todos los requisitos. Desde la aparición del dispositivo AnaConDa® y según las últimas recomendaciones, el sevoflurano se ha convertido en una alternativa para el paciente neurocrítico. Una de las consecuencias de la utilización del dispositivo es el aumento del espacio muerto anatómico instrumental que produce una disminución de la ventilación alveolar. Si la disminución de la ventilación alveolar no se compensa con un aumento del volumen minuto se producirá un aumento de la PaCO2. Presentamos el caso de un paciente con traumatismo craneoencefálico severo en el que se produjo un aumento de la presión endocraneal como consecuencia del aumento de la PaCO2 tras colocar el dispositivo AnaConDa® para sedación (AU)

[Intracranial hypertension related to sedation with sevoflurane using the AnaConDa(®) device in a patient with severe traumatic brain injury]. / Hipertensión endocraneal asociada a la sedación con sevoflurano mediante el dispositivo AnaConDa(®)en un paciente con traumatismo craneoencefálico severo.

Sedation in neurocritical patients remains a challenge as there is no drug that meets all the requirements. Since the appearance of the AnaConDa(®) device, and according to the latest recommendations, sevoflurane has become an alternative for patients with brain injury. The use of AnaConDa(®) produces an increase in the anatomical dead space that leads to a decrease in alveolar ventilation. If the decrease in the alveolar ventilation is not offset by an increase in minute volume, there will be an increase in PaCO2. We report the case of a patient with severe traumatic brain injury who suffered an increase in intracranial pressure as a result of increased PaCO2 after starting sedation with the AnaConDa(®) device.

Hyaline cartilage surface study with an environmental scanning electron microscope. An experimental study.

To obtain images of the articular surface of fresh osteochondral grafts using an environmental scanning electron microscope (ESEM). To evaluate and compare the main morphological aspects of the chondral surface of the fresh grafts. To develop a validated classification system on the basis of the images obtained via the ESEM. The study was based on osteochondral fragments from the internal condyle of the knee joint of New Zealand rabbits, corresponding to fresh chondral surface. One hundred images were obtained via the ESEM and these were classified by two observers according to a category system. The Kappa index and the corresponding confidence interval (CI) were calculated. Of the samples analysed, 62-72% had an even surface. Among the samples with an uneven surface 17-22% had a hillocky appearance and 12-16% a knobbly appearance. As regards splits, these were not observed in 92-95% of the surfaces; 4-7% showed superficial splits and only 1% deep splits. In 78-82% of cases no lacunae in the surface were observed, while 17-20% showed filled lacunae and only 1-2% presented empty lacunae. The study demonstrates that the ESEM is useful for obtaining and classifying images of osteochondral grafts.

Knee osteoarthritis: interpretation variability of radiological signs.

The aim of this study was (1) to determine the variability in detecting radiological signs of knee osteoarthritis (OA) between an orthopaedics specialist, a fourth-year resident in the speciality and a recently qualified doctor and (2) to determine which of the existing criteria show the greatest variability when used by the three participants to detect the degree of evolution of the pathology. This observational study included radiographs of 95 patients with knee pain. Osteophytes, narrowing of joint space (excluding inter-osteophyte bridges) subchondral sclerosis, subchondral cysts, collapse of the central joint cortical bone and lateral deformity, according to the criteria of Kellgren and Lawrence, modified by Kallman et al. were evaluated. Anteroposterior radiographs were used. Knees that had undergone previous surgery were excluded. Cohen's kappa index was used to calculate the degree of agreement between observers. The concordance analysis showed a low level of agreement among the three observers of the radiological variables with a maximum of 50% in some parameters. The authors discuss the possible causes of this low level of agreement. The low degree of agreement of 50% among the three observers is in line with previous reports and suggests that better training of observers is necessary and that the use of any classification is problematic.

Angioleiomyoma of the lower extremity.

Angioleiomyomas are benign soft tissue lesions that should be included in the differential diagnosis of any pedal soft tissue mass. There should be an increased index of suspicion for angioleiomyoma, especially when a freely movable subcutaneous mass is encountered in a middle-aged female patient. Treatment of such masses should involve surgical excision to relieve the symptomatology and to obtain tissue for a definitive histologic analysis. If the mass recurs, then the possibility of leiomyosarcoma should be explored.

Arthroscopic stabilization of the ankle.

Arthroscopic lateral ankle stabilization is a method for repair of the anterior talofibular ligament which involves decreased morbidity and minimal soft tissue disruption while restoring function and stability to the joint. This technique utilizes soft tissue anchoring systems that reinforce or repair the anterior talofibular ligament. Several techniques are described for the various types of ligamentous injuries. These methods are compared and contrasted with standard open reconstructive and reparative techniques. Advantages of the newer anchoring systems are discussed.