91 research outputs found
Impacts and environmental risks of oil spills on marine invertebrates, algae and seagrass: a global review from an Australian perspective
Marine invertebrates and macrophytes are sensitive to the toxic effects of oil. Depending on the intensity, duration and circumstances of the exposure, they can suffer high levels of initial mortality together with prolonged sublethal effects that can act at individual, population and community levels. Under some circumstances, recovery from these impacts can take years to decades. However, effects are variable because some taxa are less sensitive than others, and many factors can mitigate the degree of exposure, meaning that impacts are moderate in many cases, and recovery occurs within a few years. Exposure is affected by a myriad of factors including: Type and amount of oil, extent of weathering, persistence of exposure, application of dispersants or other clean-up measures, habitat type, temperature and depth, species present and their stage of development or maturity, and processes of recolonisation, particularly recruitment. Almost every oil spill is unique in terms of its impact because of differing levels of exposure and the type of habitats, communities and species assemblages in the receiving environment. Between 1970 and February 2017, there were 51 significant oil spills in Australia. Five occurred offshore with negligible likely or expected impacts. Of the others, only 24 of the spills were studied in detail, while 19 had only cursory or no assessment despite the potential for oil spills to impact the marine environment. The majority were limited to temperate waters, although 10 of the 14 spills since 2000 were in tropical coastal or offshore areas, seven were in north Queensland in areas close to the Great Barrier Reef. All four spills that have occurred from offshore petroleum industry infrastructure have occurred since 2009. In Australia, as elsewhere, a prespill need exists to assess the risk of a spill, establish environmental baselines, determine the likely exposure of the receiving environment, and test the toxicity of the oil against key animal and plant species in the area of potential impact. Subsequent to any spill, the baseline provides a reference for targeted impact monitoring
Validation of U.S. mortality prediction models for hospitalised heart failure in the United Kingdom and Japan
Aims Prognostic models for hospitalized heart failure (HHF) were developed predominantly for patients of European origin in the United States of America; it is unclear whether they perform similarly in other health care systems or for different ethnicities. We sought to validate published prediction models for HHF in the United Kingdom (UK) and Japan. Methods and results Patients in the UK (nā=894) and Japan (nā=3158) were prospectively enrolled and were similar in terms of sex (ā¼60% men) and median age (ā¼77āyears). Models predicted that British patients would have a higher mortality than Japanese, which was indeed true both for ināhospital (4.8% vs. 2.5%) and 180āday (20.7% vs. 9.5%) mortality. The model cāstatistics for the published/derivation (range 0.70ā0.76) and Japanese (range 0.75ā0.77) cohorts were similar and higher than for the UK (0.62ā0.75) but models consistently overestimated mortality in Japan. For ināhospital mortality, the OPTIMIZEāHF model performed best, providing similar discrimination in published/derivation, UK and Japanese cohorts [cāindices: 0.75 (0.74ā0.77); 0.75 (0.68ā0.81); and 0.77 (0.70ā0.83), respectively], and least overestimated mortality in Japan. For 180āday mortality, the cāstatistics for the ASCENDāHF model were similar in published/derivation (0.70) and UK [0.69 (0.64ā0.74)] cohorts but higher in Japan [0.75 (0.71ā0.79)]; calibration was good in the UK but again overestimated mortality in Japan. Conclusion Calibration of published prediction models appears moderately accurate and unbiased when applied to British patients but consistently overestimates mortality in Japan. Identifying the reason why patients in Japan have a better than predicted prognosis is of great interest
Metabolic Profiling of an Echinostoma caproni Infection in the Mouse for Biomarker Discovery
Consumption of raw fish and other freshwater products can lead to unpleasant worm infections. Indeed, such worm infections are of growing public health and veterinary concern, but they are often neglected, partially explained by the difficulty of accurate diagnosis. In the present study we infected 12 mice with an intestinal worm (i.e., Echinostoma caproni) and collected blood, stool, and urine samples 7 times between 1 and 33 days after the infection. At the same time points, blood, stool, and urine were also sampled from 12 uninfected mice. These biofluid samples were examined with a spectrometer and data were analyzed with a multivariate approach. We observed important differences between the infected and the uninfected control animals. For example, we found an increased level of branched chain amino acids in the stool of infected mice and subsequent depletion in blood plasma. Additionally, we observed changes related to a disturbed intestinal bacterial composition, particularly in urine and stool. The combination of results from the three types of biofluids gave the most comprehensive characterization of an E.Ā caproni infection in the mouse. Urine would be the biofluid of choice for diagnosis of an infection because the ease of sample collection and the high number and extent of changed metabolites
Cost effectiveness of epidural steroid injections to manage chronic lower back pain
Background
The efficacy of epidural steroid injections in the management of chronic low back pain is disputed, yet the technique remains popular amongst physicians and patients alike. This study assesses the cost effectiveness of injections administered in a routine outpatient setting in England.
Methods
Patients attending the Nottingham University Hospitalsā Pain Clinic received two injections of methylprednisolone plus levobupivacaine at different dosages, separated by at least 12āweeks. Prior to each injection, and every week thereafter for 12āweeks, participants completed the EQ-5D health-related quality of life instrument. For each patient for each injection, total health state utility gain relative to baseline was calculated. The cost of the procedure was modelled from observed clinical practice. Cost effectiveness was calculated as procedure cost relative to utility gain.
Results
39 patients provided records. Over a 13-week period commencing with injection, mean quality adjusted life year (QALY) gains per patient for the two dosages were 0.028 (SD 0.063) and 0.021 (SD 0.057). The difference in QALYs gained by dosage was insignificant (paired t-test, CIs -0.019 ā 0.033). Based on modelled resource use and data from other studies, the mean cost of an injection was estimated at Ā£219 (SD 83). The cost utility ratio of the two injections amounted to Ā£8,975 per QALY gained (CIs 5,480 ā 22,915). However, at costs equivalent to the tariff price typically paid to providers by health care purchasers, the ratio increased to Ā£27,459 (CIs 16,779 ā 70,091).
Conclusions
When provided in an outpatient setting, epidural steroid injections are a short term, but nevertheless cost effective, means of managing chronic low back pain. However, designation of the procedure as a day case requires the National Health Service to reimburse providers at a price which pushes the procedure to the margin of cost effectiveness
Studying nanotoxic effects of CdTe quantum dots in Trypanosoma cruzi
Semiconductor nanoparticles, such as quantum dots (QDs), were used to carry out experiments in vivo and ex vivo with Trypanosoma cruzi. However, questions have been raised regarding the nanotoxicity of QDs in living cells, microorganisms, tissues and whole animals. The objective of this paper was to conduct a QD nanotoxicity study on living T. cruzi protozoa using analytical methods. This was accomplished using in vitro experiments to test the interference of the QDs on parasite development, morphology and viability. Our results show that after 72 h, a 200 Ī¼M cadmium telluride (CdTe) QD solution induced important morphological alterations in T. cruzi, such as DNA damage, plasma membrane blebbing and mitochondrial swelling. Flow cytometry assays showed no damage to the plasma membrane when incubated with 200 Ī¼M CdTe QDs for up to 72 h (propidium iodide cells), giving no evidence of classical necrosis. Parasites incubated with 2 Ī¼M CdTe QDs still proliferated after seven days. In summary, a low concentration of CdTe QDs (2 Ī¼M) is optimal for bioimaging, whereas a high concentration (200 Ī¼M CdTe) could be toxic to cells. Taken together, our data indicate that 2 Ī¼M QD can be used for the successful long-term study of the parasite-vector interaction in real time
Immunomodulatory role of Keratin 76 in oral and gastric cancer
Keratin 76 (Krt76) is an epithelial differentiation marker that is downregulated in oral squamous cell carcinomas, correlating with poor prognosis. Here the authors show that genetic ablation of Krt76 in a mouse model results in increased susceptibility to carcinogenesis via enhanced accumulation of Tregs
Selective targeting of microglia by quantum dots
<p>Abstract</p> <p>Background</p> <p>Microglia, the resident immune cells of the brain, have been implicated in brain injury and various neurological disorders. However, their precise roles in different pathophysiological situations remain enigmatic and may range from detrimental to protective. Targeting the delivery of biologically active compounds to microglia could help elucidate these roles and facilitate the therapeutic modulation of microglial functions in neurological diseases.</p> <p>Methods</p> <p>Here we employ primary cell cultures and stereotaxic injections into mouse brain to investigate the cell type specific localization of semiconductor quantum dots (QDs) in vitro and in vivo. Two potential receptors for QDs are identified using pharmacological inhibitors and neutralizing antibodies.</p> <p>Results</p> <p>In mixed primary cortical cultures, QDs were selectively taken up by microglia; this uptake was decreased by inhibitors of clathrin-dependent endocytosis, implicating the endosomal pathway as the major route of entry for QDs into microglia. Furthermore, inhibiting mannose receptors and macrophage scavenger receptors blocked the uptake of QDs by microglia, indicating that QD uptake occurs through microglia-specific receptor endocytosis. When injected into the brain, QDs were taken up primarily by microglia and with high efficiency. In primary cortical cultures, QDs conjugated to the toxin saporin depleted microglia in mixed primary cortical cultures, protecting neurons in these cultures against amyloid beta-induced neurotoxicity.</p> <p>Conclusions</p> <p>These findings demonstrate that QDs can be used to specifically label and modulate microglia in primary cortical cultures and in brain and may allow for the selective delivery of therapeutic agents to these cells.</p
A meta-analysis of the relationship between brain dopamine receptors and obesity: a matter of changes in behavior rather than food addiction?
Addiction to a wide range of substances of abuse has been suggested to reflect a āReward Deficiency Syndrome'. That is, drugs are said to stimulate the reward mechanisms so intensely that, to compensate, the population of dopamine D(2) receptors (DD2R) declines. The result is that an increased intake is necessary to experience the same degree of reward. Without an additional intake, cravings and withdrawal symptoms result. A suggestion is that food addiction, in a similar manner to drugs of abuse, decrease DD2R. The role of DD2R in obesity was therefore examined by examining the association between body mass index (BMI) and the Taq1A polymorphism, as the A1 allele is associated with a 30ā40% lower number of DD2R, and is a risk factor for drug addiction. If a lower density of DD2R is indicative of physical addiction, it was argued that if food addiction occurs, those with the A1 allele should have a higher BMI. A systematic review found 33 studies that compared the BMI of those who did and did not have the A1 allele. A meta-analysis of the studies compared those with (A1/A1 and A1/A2) or without (A2/A2) the A1 allele; no difference in BMI was found (standardized mean difference 0.004 (s.e. 0.021), variance 0.000, Z=0.196, P<0.845). It was concluded that there was no support for a reward deficiency theory of food addiction. In contrast, there are several reports that those with the A1 allele are less able to benefit from an intervention that aimed to reduce weight, possibly a reflection of increased impulsivity
Tetradecylthioacetic Acid Increases Hepatic Mitochondrial Ī²-Oxidation and Alters Fatty Acid Composition in a Mouse Model of Chronic Inflammation
The administration of tetradecylthioacetic acid (TTA), a hypolipidemic and anti-inflammatory modified bioactive fatty acid, has in several experiments based on high fat diets been shown to improve lipid transport and utilization. It was suggested that increased mitochondrial and peroxisomal fatty acid oxidation in the liver of Wistar rats results in reduced plasma triacylglycerol (TAG) levels. Here we assessed the potential of TTA to prevent tumor necrosis factor (TNF) Ī±-induced lipid modifications in human TNFĪ± (hTNFĪ±) transgenic mice. These mice are characterized by reduced Ī²-oxidation and changed fatty acid composition in the liver. The effect of dietary treatment with TTA on persistent, low-grade hTNFĪ± overexpression in mice showed a beneficial effect through decreasing TAG plasma concentrations and positively affecting saturated and monounsaturated fatty acid proportions in the liver, leading to an increased anti-inflammatory fatty acid index in this group. We also observed an increase of mitochondrial Ī²-oxidation in the livers of TTA treated mice. Concomitantly, there were enhanced plasma levels of carnitine, acetyl carnitine, propionyl carnitine, and octanoyl carnitine, no changed levels in trimethyllysine and palmitoyl carnitine, and a decreased level of the precursor for carnitine, called Ī³-butyrobetaine. Nevertheless, TTA administration led to increased hepatic TAG levels that warrant further investigations to ascertain that TTA may be a promising candidate for use in the amelioration of inflammatory disorders characterized by changed lipid metabolism due to raised TNFĪ± levels
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