Individual and combined impacts of carbon dioxide enrichment, heatwaves, flow velocity variability, and fine sediment deposition on stream invertebrate communities.

Climate change and land-use change are widely altering freshwater ecosystem functioning and there is an urgent need to understand how these broad stressor categories may interact in future. While much research has focused on mean temperature increases, climate change also involves increasing variability of both water temperature and flow regimes and increasing concentrations of atmospheric CO2, all with potential to alter stream invertebrate communities. Deposited fine sediment is a pervasive land-use stressor with widespread impacts on stream invertebrates. Sedimentation may be managed at the catchment scale; thus, uncovering interactions with these three key climate stressors may assist mitigation of future threats. This is the first experiment to investigate the individual and combined effects of enriched CO2, heatwaves, flow velocity variability, and fine sediment on realistic stream invertebrate communities. Using 128 mesocosms simulating small stony-bottomed streams in a 7-week experiment, we manipulated dissolved CO2 (ambient; enriched), fine sediment (no sediment; 300 g dry sediment), temperature (ambient; two 7-day heatwaves), and flow velocity (constant; variable). All treatments changed community composition. CO2 enrichment reduced abundances of Orthocladiinae and Chironominae and increased Copepoda abundance. Variable flow velocity had only positive effects on invertebrate abundances (7 of 13 common taxa and total abundance), in contrast to previous experiments showing negative impacts of reduced velocity. CO2 was implicated in most stressor interactions found, with CO2 × sediment interactions being most common. Communities forming under enriched CO2 conditions in sediment-impacted mesocosms had ~20% fewer total invertebrates than those with either treatment alone. Copepoda abundances doubled in CO2-enriched mesocosms without sediment, whereas no CO2 effect occurred in mesocosms with sediment. Our findings provide new insights into potential future impacts of climate change and land use in running freshwaters, in particular highlighting the potential for elevated CO2 to interact with fine sediment deposition in unpredictable ways.

Habitat influences skeletal morphology and density in the snailfishes (family Liparidae).

We tested the hypothesis that deep-sea fishes have poorly mineralized bone relative to shallower-dwelling species using data from a single family that spans a large depth range. The family Liparidae (snailfishes, Cottiformes) has representatives across the entire habitable depth range for bony fishes (0 m-> 8000 m), making them an ideal model for studying depth-related trends in a confined phylogeny. We used micro-computed tomography (micro-CT) scanning to test three aspects of skeletal reduction in snailfishes (50 species) across a full range of habitat depths: 1) reduction of structural dimensions, 2) loss of skeletal elements, and 3) reduction in bone density. Using depth data from the literature, we found that with increasing depth, the length of the dentary, neurocranium, and suborbital bones decreases. The ventral suction disk decreases width with increasing maximum habitat depth and is lost entirely in some deeper-living taxa, though not all. Although visual declines in bone density in deeper-living taxa were evident across full skeletons, individual densities of the lower jaw, vertebra, suction disk, hypural plate, and otoliths did not significantly decline with any depth metric. However, pelagic and polar taxa tended to show lower density bones compared to other species in the family. We propose that skeletal reductions allow snailfishes to maintain neutral buoyancy at great depths in the water column, while supporting efficient feeding and locomotion strategies. These findings suggest that changes in skeletal structure are non-linear and are driven not only by hydrostatic pressure, but by other environmental factors and by evolutionary ancestry, calling the existing paradigm into question.

Accuracy of WatchPAT for the Diagnosis of Obstructive Sleep Apnea in Patients with Chronic Obstructive Pulmonary Disease.

The co-existence of chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA), termed the overlap syndrome (OVS), is associated with adverse outcomes that may be reversed with treatment. However, diagnosis is limited by the apparent need for in-laboratory polysomnography (PSG). WatchPAT is a portable diagnostic device that is validated for the diagnosis of OSA that might represent an attractive tool for the diagnosis of OVS.Subjects with established COPD were recruited from a general population. Subjects underwent PSG and simultaneous recording with WatchPAT. Pulmonary function testing and questionnaires were also performed.A total of 36 subjects were recruited and valid data was obtained on 33 (age 63 ± 7, BMI 28 ± 7, 61% male, FEV1 56 ± 20% predicted). There was no significant difference in the apnea-hypopnea index (AHI) between PSG and WatchPAT (19 ± 20 versus 20 ± 15 events/h; mean difference 2(-2, 5) events/h; p = 0.381). The AHI was not significantly different in rapid eye movement (REM) and non-rapid eye movement (NREM) determined by PSG versus REM and NREM determined by WatchPAT. WatchPAT slightly overestimated total and REM sleep time, and sleep efficiency. The sensitivity of WatchPAT at an AHI cut-off of ≥5, ≥15, and ≥30 events/h for corresponding PSG AHI cut-offs was 95.8, 92.3, and 88.9, respectively; specificity was 55, 65.0, and 95.8, respectively.WatchPAT is able to determine OSA reliably in patients with COPD. The availability of this additional diagnostic modality may lead to improved detection of OVS, which may in turn lead to improved outcomes for a group of COPD patients at high risk of poor outcomes.

The Organization of Right Prefrontal Networks Reveals Common Mechanisms of Inhibitory Regulation Across Cognitive, Emotional, and Motor Processes.

Inhibitory control/regulation is critical to adapt behavior in accordance with changing environmental circumstances. Dysfunctional inhibitory regulation is ubiquitous in neurological and psychiatric populations. These populations exhibit dysfunction across psychological domains, including memory/thought, emotion/affect, and motor response. Although investigation examining inhibitory regulation within a single domain has begun outlining the basic neural mechanisms supporting regulation, it is unknown how the neural mechanisms of these domains interact. To investigate the organization of inhibitory neural networks within and across domains, we used neuroimaging to outline the functional and anatomical pathways that comprise inhibitory neural networks regulating cognitive, emotional, and motor processes. Networks were defined at the group level using an array of analyses to indicate their intrinsic pathway structure, which was subsequently assessed to determine how the pathways explained individual differences in behavior. Results reveal how neural networks underlying inhibitory regulation are organized both within and across domains, and indicate overlapping/common neural elements.

Successful long-term outcome of liver transplantation in late-onset lysosomal acid lipase deficiency.

Late-onset LAL deficiency, previously referred to as cholesteryl ester storage disorder, is a rare lysosomal storage disorder characterized by accumulation of cholesteryl esters. It has a heterogeneous clinical phenotype including abdominal pain, poor growth, hyperlipidemia with vascular complications and hepatosplenomegaly. End-stage liver disease may occur, but there are few reports of successful LT. There are also concerns that systemic manifestations of the disease might persist post-LT. We report a case with excellent outcome eight yr following LT. The subject was noted to have asymptomatic hepatosplenomegaly during an intercurrent illness, and LAL deficiency was confirmed with compound heterozygosity in the LIPA. Despite dietary fat restriction, he developed signs of progressive liver disease and subsequently developed hepatopulmonary syndrome. He underwent cadaveric LT at the age of nine and a half yr and recovered with prompt resolution of hepatopulmonary syndrome. Eight yr post-transplant he has normal growth, normal lipid profile, and liver and renal function tests. Liver histology showed no evidence of disease recurrence at this stage. LT in this subject resulted in an excellent functional correction of late-onset LAL deficiency.

Orbitofrontal cortex volume and brain reward response in obesity.

BACKGROUND/OBJECTIVES: What drives overconsumption of food is poorly understood. Alterations in brain structure and function could contribute to increased food seeking. Recently, brain orbitofrontal cortex (OFC) volume has been implicated in dysregulated eating but little is known how brain structure relates to function. SUBJECTS/METHODS: We examined obese (n=18, age=28.7±8.3 years) and healthy control women (n=24, age=27.4±6.3 years) using a multimodal brain imaging approach. We applied magnetic resonance and diffusion tensor imaging to study brain gray and white matter volume as well as white matter (WM) integrity, and tested whether orbitofrontal cortex volume predicts brain reward circuitry activation in a taste reinforcement-learning paradigm that has been associated with dopamine function. RESULTS: Obese individuals displayed lower gray and associated white matter volumes (P<0.05 family-wise error (FWE)- small volume corrected) compared with controls in the orbitofrontal cortex, striatum and insula. White matter integrity was reduced in obese individuals in fiber tracts including the external capsule, corona radiata, sagittal stratum, and the uncinate, inferior fronto-occipital, and inferior longitudinal fasciculi. Gray matter volume of the gyrus rectus at the medial edge of the orbitofrontal cortex predicted functional taste reward-learning response in frontal cortex, insula, basal ganglia, amygdala, hypothalamus and anterior cingulate cortex in control but not obese individuals. CONCLUSIONS: This study indicates a strong association between medial orbitofrontal cortex volume and taste reinforcement-learning activation in the brain in control but not in obese women. Lower brain volumes in the orbitofrontal cortex and other brain regions associated with taste reward function as well as lower integrity of connecting pathways in obesity (OB) may support a more widespread disruption of reward pathways. The medial orbitofrontal cortex is an important structure in the termination of food intake and disturbances in this and related structures could contribute to overconsumption of food in obesity.

Cardiopulmonary exercise testing: arm crank vs cycle ergometry.

This pilot study compared oxygen consumption during arm crank and cycle ergometer tests in 15 women. The mean (SD) peak oxygen consumption was less with arm cranking (25 (5) ml.kg(-1) .min(-1)) than with cycling (40 (7) ml.kg(-1) .min(-1)), p < 0.0001. The mean (SD) anaerobic threshold was less with arm cranking (13 (2) ml.kg(-1) .min(-1)) than with cycling (20 (4) ml.kg(-1) .min(-1)), p < 0.0001. There was moderate correlation, r(2) = 0.60, between the anaerobic thresholds determined by arm and leg exercise, p = 0.0007. This study suggests that arm crank cardiopulmonary exercise testing could be used for pre-operative assessment in those unable to cycle.

Measurement of functional residual capacity by modified multiple breath nitrogen washout for spontaneously breathing and mechanically ventilated patients.

BACKGROUND: There is a need for a bedside functional residual capacity (FRC) measurement method that performs well in intensive care patients during many modes of ventilation including controlled, assisted, spontaneous, and mixed. We developed a modified multiple breath nitrogen washout method for FRC measurement that relies on end-tidal gas fractions and alveolar tidal volume measurements as inputs but does not require the traditional measurements of volume of nitrogen or oxygen. Using end-tidal measurements, not volume, reduces errors from signal synchronization. This study was designed to assess the accuracy, precision, and repeatability of the proposed FRC system in subjects with variable ventilation patterns including some spontaneous effort. METHODS: The accuracy and precision of measurements were assessed by comparing the novel N2 washout FRC values to the gold standard, body plethysmography, in 20 spontaneously breathing volunteers. Repeatability was assessed by comparing subsequent measurements in 20 intensive care patients whose lungs were under controlled and assisted mechanical ventilation. RESULTS: Compared with body plethysmography, the accuracy (mean bias) of the novel method was -0.004 litre and precision [1 standard deviation (sd)] was 0.209 litre [mean (sd)] [-0.1 (5.9)% of body plethysmography]. The difference between repeated measurements was 0.009 (0.15) litre [mean (sd)] [0.4 (6.4)%]. The coefficient of repeatability was 0.31 litre (12.7%). CONCLUSIONS: The modified multiple breath nitrogen washout method for FRC measurement provides improved precision and equivalent accuracy and repeatability compared with existing methods during ventilation with variable ventilation patterns. Further study of the novel N2 washout method is needed.

The evolutionary origins of Syngnathidae: pipefishes and seahorses.

Despite their importance as evolutionary and ecological model systems, the phylogenetic relationships among gasterosteiforms remain poorly understood, complicating efforts to understand the evolutionary origins of the exceptional morphological and behavioural diversity of this group. The present review summarizes current knowledge on the origin and evolution of syngnathids, a gasterosteiform family with a highly developed form of male parental care, combining inferences based on morphological and molecular data with paleontological evidence documenting the evolutionary history of the group. Molecular methods have provided new tools for the study of syngnathid relationships and have played an important role in recent conservation efforts. Despite recent insights into syngnathid evolution, however, a survey of the literature reveals a strong taxonomic bias towards studies on the species-rich genera Hippocampus and Syngnathus, with a lack of data for many morphologically unique members of the family. The study of the evolutionary pressures responsible for generating the high diversity of syngnathids would benefit from a wider perspective, providing a comparative framework in which to investigate the evolution of the genetic, morphological and behavioural traits of the group as a whole.

Optimisation of the mechanical and handling properties of an injectable calcium phosphate cement.

Calcium phosphate cements have the potential to be successful in minimally invasive surgical techniques, like that of vertebroplasty, due to their ability to be injected into a specific bone cavity. These bone cements set to produce a material similar to that of the natural mineral component in bone. Due to the ceramic nature of these materials they are highly brittle and it has been found that they are difficult to inject. This study was carried out to determine the factors that have the greatest effect on the mechanical and handling properties of an apatitic calcium phosphate cement with the use of a Design of Experiments (DoE) approach. The properties of the cement were predominantly influenced by the liquid:powder ratio and weight percent of di-sodium hydrogen phosphate within the liquid phase. An optimum cement composition was hypothesised and tested. The mechanical properties of the optimised cement were within the clinical range for vertebroplasty, however, the handling properties still require improvement.

Evaluation of Data-Based Estimates of Anthropogenic Carbon in the Arctic Ocean.

The Arctic Ocean is particularly vulnerable to ocean acidification, a process that is mainly driven by the uptake of anthropogenic carbon (Cant) from the atmosphere. Although Cant concentrations cannot be measured directly in the ocean, they have been estimated using data-based methods such as the transient time distribution (TTD) approach, which characterizes the ventilation of water masses with inert transient tracers, such as CFC-12. Here, we evaluate the TTD approach in the Arctic Ocean using an eddying ocean model as a test bed. When the TTD approach is applied to simulated CFC-12 in that model, it underestimates the same model's directly simulated Cant concentrations by up to 12%, a bias that stems from its idealized assumption of gas equilibrium between atmosphere and surface water, both for CFC-12 and anthropogenic CO2. Unlike the idealized assumption, the simulated partial pressure of CFC-12 (pCFC-12) in Arctic surface waters is undersaturated relative to that in the atmosphere in regions and times of deep-water formation, while the simulated equivalent for Cant is supersaturated. After accounting for the TTD approach's negative bias, the total amount of Cant in the Arctic Ocean in 2005 increases by 8% to 3.3 ± 0.3 Pg C. By combining the adjusted TTD approach with scenarios of future atmospheric CO2, it is estimated that all Arctic waters, from surface to depth, would become corrosive to aragonite by the middle of the next century even if atmospheric CO2 could be stabilized at 540 ppm.

Inhibition of thromboxane A2-induced arrhythmias and intracellular calcium changes in cardiac myocytes by blockade of the inositol trisphosphate pathway.

We have recently reported that left atrial injections of the thromboxane A(2) (TXA(2)) mimetic, (5Z)-7-[(1R,4S,5S,6R)-6-[(1E,3S)-3-hydroxy-1-octenyl]-2 -oxabicyclo[2.2.1]hept-5-yl]-5-heptenoic acid (U46619), induced ventricular arrhythmias in the anesthetized rabbit. Data from this study led us to hypothesize that TXA(2) may be inducing direct actions on the myocardium to induce these arrhythmias. The aim of this study was to further elucidate the mechanism responsible for these arrhythmias. We report that TXA(2)R is expressed at both the gene and protein levels in atrial and ventricular samples of adult rabbits. In addition, TXA(2)R mRNA was identified in single, isolated ventricular cardiac myocytes. Furthermore, treatment of isolated cardiac myocytes with U46619 increased intracellular calcium in a dose-dependent manner and these increases were blocked by the specific TXA(2)R antagonist, 7-(3-((2-((phenylamino)carbonyl)hydrazino)methyl)-7-oxabicyclo(2.2.1)hept-2-yl)-5-heptenoic acid (SQ29548). Pretreatment of myocytes with an inhibitor of inositol trisphosphate (IP(3)) formation, gentamicin, or with an inhibitor of IP(3) receptors, 2-aminoethoxydiphenylborate (2-APB), blocked the increase in intracellular calcium. In vivo pretreatment of anesthetized rabbits with either gentamicin or 2-APB subsequently inhibited the formation of ventricular arrhythmias elicited by U46619. These data support the hypothesis that TXA(2) can induce arrhythmias via a direct action on cardiac myocytes. Furthermore, these arrhythmogenic actions were blocked by inhibitors of the IP(3) pathway. In summary, this study provides novel evidence for direct TXA(2)-induced cardiac arrhythmias and provides a rationale for IP(3) as a potential target for the treatment of TXA(2)-mediated arrhythmias.

Occupancy principle for radioactive tracers in steady-state biological systems.

Bergner's theoretical analysis of tracer dynamics has important ap plications in biology, not only for the measurement of exchangeable mass (as he demonstrated) but also for elicitation of otherwise inaccessible information on total masses of particular elements in body organs or systems-as well as in Chemical engineering and geophysics.

Temporospatial parameters of hip replacement patients ten years post-operatively.

While short-term outcome studies of patients following total hip arthroplasty (THA) have shown compromised walking ability, it is often assumed that temporospatial parameters will return to normal levels at long-term follow-up, especially for younger patients. Temporospatial parameters were determined for 149 THA patients selected arbitrarily from routine ten-year post-operative review clinics. Patients were divided into five age groups: 54-64, 65-69, 70-74, 75-79 and over 80 years. The parameters of speed, step length, stride length and cadence were measured. All age groups displayed significantly reduced velocity, step length and stride length compared to an age-matched normal group. There was no difference in most of the temporospatial parameters between the age groups. This study shows that even younger THA patients at long-term follow-up do not regain normal age-matched walking characteristics.

Statins in the spectrum of neurologic disease.

Overwhelming evidence now shows that 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (ie, statins) are safe and effective in primary and secondary prevention of cardiovascular disease. Atherosclerosis, the primary cause of heart disease, is directly and independently related to hypercholesterolemia and inflammation, and statins have multiple and independent effects on these conditions. New evidence for the use of statins in neurologic disease is mounting, and the range of therapeutic applications is formidable. Statins are beginning to show benefits in a wide range of neurologic conditions, from common ischemic stroke to rare congenital neurometabolic storage diseases, from acute brain injury to chronic central nervous system inflammation, and from prevention of neurodegenerative disease to acute neuroprotection. A diverse therapeutic spectrum is explained by shared pathogenetic mechanisms of neurologic disease and the manifold pharmacodynamic effects of statins.

Wear paths produced by individual hip-replacement patients--a large-scale, long-term follow-up study.

Wear particle accumulation is one of the main contributors to osteolysis and implant failure in hip replacements. Altered kinematics produce significant differences in wear rates of hip replacements in simulator studies due to varying degrees of multidirectional motion. Gait analysis data from 153 hip-replacement patients 10-years post-operation were used to model two- and three-dimensional wear paths for each patient. Wear paths were quantified in two dimensions using aspect ratios and in three dimensions using the surface areas of the wear paths, with wear-path surface area correlating poorly with aspect ratio. The average aspect ratio of the patients wear paths was 3.97 (standard deviation=1.38), ranging from 2.13 to 10.86. Sixty percent of patients displayed aspect ratios between 2.50 and 3.99. However, 13% of patients displayed wear paths with aspect ratios >5.5, which indicates reduced multidirectional motion. The majority of total hip replacement (THR) patients display gait kinematics which produce multidirectional wear paths, but a significant minority display more linear paths.

Ureteroarterial fistulas after radical pelvic surgery: pathogenesis, diagnosis, and therapeutic modalities.

Ureteroarterial fistulas (UAF) are a rare but potentially life-threatening complication of intra-abdominal malignancy, typically occurring after vascular or pelvic surgery. Patients with a history of radical pelvic surgery, chronic indwelling ureteral stents, and prior pelvic radiation appear to be at increased risk. The predisposing risk factors suggest that gynecological oncologists are the likely specialty to face this problem and should be familiar with the clinical presentation and etiology of UAF. We present two such cases to illustrate these salient points of clinical diagnosis and management.

Gait kinematics of age-stratified hip replacement patients--a large scale, long-term follow-up study.

Three-dimensional gait analysis data from 134 patients attending routine 10-year post-operative review clinics is presented. Patients were divided into five age groups-54-64 years, 65-69 years, 70-74 years, 75-79 years and over 80 years. A group of 10 normal elderly subjects was also tested. All age groups displayed reduced range of hip flexion/extension, range of knee flexion extension, maximum hip extension and range of hip abduction/adduction and reduced velocity and step length compared to the normal elderly group. However, there was no difference in gait kinematics between the age groups. Patients over 80 years of age displayed significantly reduced range of sagittal plane ankle motion, but this is unlikely to be secondary to hip joint restriction and more likely due to reduced walking speed associated with very elderly subjects. This study reveals that even the youngest hip replacement patients do not attain normal gait kinematics 10-year post-operatively and that muscle atrophy and residual stiffness may influence patient kinematics many years post-operation.