Toxicity of lead, cadmium and mercury on embryogenesis, survival, growth and metamorphosis of Meretrix meretrix larvae

In order to assess the toxicity of heavy metals on the early development of Meretrix meretrix, the effects of mercury (Hg), cadmium (Cd) and lead (Pb) on embryogenesis, survival, growth and metamorphosis of larvae were investigated. The EC50 for embryogenesis was 5.4 mu g l(-1) for Hg, 1014 mu g l(-1) for Cd and 297 mu g l(-1) for Pb, respectively. The 96 h LC50 for D-shaped larvae was 14.0 mu g l(-1) for Hg, 68 mu g l(-1) for Cd and 353 mu g l(-1) for Pb, respectively. Growth was significantly retarded at 18.5 mu g l(-1) (0.1 mu M) for Hg, 104 mu g l(-1) (1 mu M) for Cd and 197 mu g l(-1) (1 mu M) for Pb, respectively. The EC50 for metamorphosis, similar to 48 h LC50, was higher than 96 h LC50. Our results indicate that the early development of M. meretrix is highly sensitive to heavy metals and can be used as a test organism for ecotoxicology bioassays in temperate and subtropical regions.

Application of rotifer Brachionus plicatilis in detecting the toxicity of harmful algae

The toxicity of seven major HAB (harmful algal bloom) species/strains, Prorocentrum donghaiense, Phaeocystis globosa, Prorocentrum micans, Alexandrium tamarense (AT-6, non-PSP producer), Alexandrium lusitanicum, Alexandrum tamarense (ATHK) and Heterosigma akashiwo were studied against rotifer Brachionus plicatilis under laboratory conditions. The results show that P. donghaiense, P. globosa, P. micans, A. tamarense (AT-6), or A. lusitanicum could maintain the individual survival and reproduction, as well as the population increase of the rotifer, but the individual reproduction would decrease when exposed to these five algae at higher densities for nine days; H. akashiwo could decrease the individual survival and reproduction, as well as population increase of the rotifer, which is similar to that of the starvation group, indicating that starvation might be its one lethal factor except for the algal toxins; A. tamarense (ATHK) has strong lethal effect on the rotifer with 48h LC50 at 800 cells/mL. The experiment on ingestion ability indicated by gut pigment change shows that P. donghaiense, P. globosa, P. micans, A. tamarense (AT-6) and A. lusitanicum can be taken by the rotifers as food, but A. tamarense (ATHK) or H. akashiwo can be ingested by the rotifers. The results indicate that all the indexes of individual survival and reproduction, population increase, gut pigment change of the rotifers are good and convenient to be used to reflect the toxicities of HAB species. Therefore, rotifer is suggested as one of the toxicity testing organisms in detecting the toxicity of harmful algae.

Immune condition of Chlamys farreri in response to acute temperature challenge

The effects of acute temperature challenge on some immune parameters of haemocyte in Zhikong scallop, Chlamys farreri, recognised as a temperature sensitive bivalve species, were evaluated over a short period of time. Scallops were suddenly transferred from 17 degrees C to 11 degrees C, 23 degrees C and 28 degrees C for a period of 72 h. Total haemocyte count (THC), percentage of phagocytic haemocytes, reactive oxygen species (ROS) production, acid phosphatase (ACP) and superoxide dismutase (SOD) activities (in both haemocyte lysate and cell-free haemolymph) were chosen as biomarkers of temperature stress. Results demonstrated that the percentage of phagocytic haemocytes and ACP activity in cell-free haemolymph of scallops challenged at 28 degrees C for 72 h significantly decreased. By contrast, reactive oxygen species production by haemocytes increased when compared to the initial values. It is concluded that haemocyte activities of C. farreri appear to be compromised when scallops were transferred from 17 degrees C to 28 degrees C. Meanwhile, no obvious negative effect of acute temperature stress was detected on haemocyte activities of C. farreri challenged at 11 degrees C, which highlighted the high tolerance of scallops to acute decrease of seawater temperatures. (C) 2007 Elsevier B.V. All rights reserved.

Effects of acute temperature or salinity stress on the immune response in sea cucumber, Apostichopus japonicus

Invertebrates are increasingly raised in mariculture, where it is important to monitor immune function and to minimize stresses that could suppress immunity. The activities of phagocytosis, superoxide dismutase (SOD), catalase (CAT), myeloperoxiclase (MPO), and lysozyme (LSZ) were measured to evaluate the immune capacities of the sea cucumber, Apostichopus japonicus, to acute temperature changes (from 12 degrees C to 0 degrees C, 8 degrees C, 16 degrees C, 24 degrees C, and 32 degrees C for 72 h) and salinity changes (from 30 parts per thousand to 20 parts per thousand, 25 parts per thousand, and 35 parts per thousand for 72 h) in the laboratory. Phagocytosis was significantly affected by temperature increases in 3 h, and by salinity (25 parts per thousand and 35 parts per thousand) changes in 1 h. SOD activities decreased significantly in 0.5 h to 6 h samples at 24 degrees C. At 32 degrees C, SOD activities decreased significantly in 0.5 h and 1 h exposures, and obviously increased for 12 h exposure. CAT activities decreased significantly at 24 degrees C for 0.5 h exposure, and increased significantly at 32 degrees C in 3 h to 12 h exposures. Activities of MPO increased significantly at 0 degrees C in 0.5 h to 6 In exposures and at 8 degrees C for 1 h. By contrast, activities of MPO decreased significantly in 24 degrees C and 32 degrees C treatments. In elevated-temperature treatments, activities of LSZ increased significantly except at 32 degrees C for 6 h to 12 h exposures. SOD activity was significantly affected by salinity change. CAT activity decreased significantly after only 1 h exposure to salinity of 20 parts per thousand.. Activities of MPO and LSZ showed that A. japonicus tolerates limited salinity stress. High-temperature stress had a much greater effect on the immune capacities of A. japonicus than did low-temperature and salinity stresses. Crown Copyright (C) 2008 Published by Elsevier Inc. All rights reserved.

The effect of acute salinity change on white spot syndrome (WSS) outbreaks in Fenneropenaeus chinensis

In order to observe the effect of salinity on disease resistance and white spot syndrome virus (WSSV) proliferation in Fenneropenaeus chinensis, shrimps with latent WSSV were subjected to two acute salinity changes from the original salinity of 22 ppt to 18 and 14 ppt in an hour, respectively. The total haemocyte count (THC) of the challenged group showed no evident change under salinity adjustments, but the phenoloxidase (PO) index declined significantly (P<0.05) corresponding to continuing acute salinity changes from the 24th to the 72nd hour. According to the WSSV load detected by quantitative real-time PCR method, it was found that WSSV carried by the challenged group and control group were significantly different (P<0.05); acute salinity change from 22 to 14 ppt led to the WSSV carried in the challenged group being significantly higher (P<0.05) than that of those surviving in 22 ppt, but salinity change from 22 to 18 ppt had no such effect. At the end of the 72-h experiment, the challenged group subjected to salinity change from 22 to 14 ppt had nearly 3 times the WSSV load as the control group with no salinity change. Therefore, salinity changes over a particular range could result in a decrease of immunocompetence and obvious WSSV proliferation in the shrimps, leading to white spot syndrome developing from a latent infection to an acute outbreak. (C) 2005 Elsevier B.V All rights reserved.

Behavioral responses of tilapia (Oreochromis niloticus) to acute fluctuations in dissolved oxygen levels as monitored by computer vision

Behavioral and ventilatory parameters have the possibility of predicting the stress state of fish in vivo and in situ. This paper presents a new image-processing algorithm for quantifying the average swimming speed of a fish school in an aquarium. This method is based on the alteration in projected area caused by the movement of individual fish during frame sequences captured at given time intervals. The image enhancement method increases the contrast between fish and background, and is thus suitable for use in turbid aquaculture water. Behavioral parameters (swimming activity and distribution parameters) and changes in ventilation frequency (VF) of tilapia (Oreochromis niloticus) responded to acute fluctuations in dissolved oxygen (DO) which were monitored continuously in the course of normoxia, falling DO level, maintenance of hypoxia (three levels of 1.5, 0.8 and 0.3 mg l(-1)) and subsequent recovery to normoxia. These parameters responded sensitively to acute variations in DO level; they displayed significant changes (P < 0.05) during severe hypoxia (0.8 and 0.3 mg l(-1) level) compared with normoxic condition, but there was no significant difference under conditions of mild hypoxia (1.5 mg l(-1) level). There was no significant difference in VF between two levels of severe hypoxia 0.8 and 0.3 mg l(-1) level during the low DO condition. The activity and distribution parameters displayed distinguishable differences between the 0.8 and 0.3 mg l(-1) levels. The behavioral parameters are thus capable of distinguishing between different degrees of severe hypoxia, though there were relatively large fluctuations. (c) 2006 Elsevier B.V. All rights reserved.

Toxicological evaluation of fucoidan extracted from Laminaria japonica in Wistar rats

Fucoidans, the sulfated polysacchrides extracted from brown algae, have been extensively studied for their diverse biological activities. However, there is no detailed report investigating the toxicity of fucoidan. In this study, the acute and subchronic (6 months) toxicity of varying levels of fucoidan extracted from Laminaria japonica was investigated in Wistar rats after oral administration. The results showed that no significant toxicological changes were observed when 300 mg/kg body weight per day fucoidan was administered to rats. But when the dose was increased to 900 and 2500 mg/kg body weight per day, the clotting time was significantly prolonged. Besides this, no other signs of toxicity were observed. Based on these results, it can be concluded that the no adverse effect level of fucoidan from L. japonica is 300 mg/kg body weight per day. (C) 2004 Elsevier Ltd. All rights reserved.

Acute peristome edema disease in juvenile and adult sea cucumbers Apostichopus japonicus (Selenka) reared in North China

Acute peristome edema disease (APED) is a new disease that broke out in cultured sea cucumber along the Shangdong and Liaoning province coasts in China, PR, and has caused a great deal of death in Apostichopus japonicus (Selenka) since 2004. Here we report virus-like particles found in intestine epithelium of sea cucumbers reared in North China. It is the first time that sea cucumbers are reported to be infected by virus. Histological examinations showed that the viral inclusion bodies existed in intestine epithelium cells. Electron microscopic examinations show that the virions were spherical, 80-100 nm in diameter, and composed of a helical nucleocapsid within an envelope with surface projections. Detailed studies on the morphogenesis of these viruses found many characteristics previously described for coronaviruses. Virus particles always congregated, and formed a virus vesicle with an encircling membrane. The most obvious cellular pathologic feature is large granular areas of cytoplasm, relatively devoid of organelles. Tubular structures within virus-containing vesicles, nucleocapsid inclusions, and double-membrane vesicles are also found in the cytopathic cells. No rickettsia, chlamydia, bacteria, or other parasitic organisms were found. (c) 2007 Elsevier Inc. All rights reserved.

Copper complexation by fulvic acid affects copper toxicity to the larvae of the polychaete Hydroides elegans

Copper toxicity is influenced by a variety of environmental factors including dissolved organic matter (DOM). We examined the complexation of copper by fulvic acid (FA), one of the major components of DOM, by measuring the decline in labile copper by anodic stripping voltammetrically (ASV). The data were described using a one-site ligand binding model, with a ligand concentration of 0.19 mu mol site mg(-1) C, and a logK' of 6.2. The model was used to predict labile copper concentration in a bioassay designed to quantify the extent to which Cu-FA complexation affected copper toxicity to the larvae of marine polychaete Hydroides elegans. The toxicity data, when expressed as labile copper concentration causing abnormal development, were independent of FA concentration and could be modeled as a logistic function, with a 48-h EC50 of 58.9 mu g 1(-1). However, when the data were expressed as a function of total copper concentration, the toxicity was dependent on FA concentration, with a 48-h EC50 ranging from 55.6 mu g 1(-1) in the no-FA control to 137.4 mu g 1(-1) in the 20 mg 1(-1) FA treatment. Thus, FA was protective against copper toxicity to the larvae, and such an effect was caused by the reduction in labile copper due to Cu-FA complexation. Our results demonstrate the potential of ASV as a useful tool for predicting metal toxicity to the larvae in coastal environment where DOM plays an important role in complexing metal ions. (c) 2007 Elsevier Ltd. All rights reserved.

The lack of associations between alleles at the hypoxia-Inducible factor 1A C1772T loci and responses to acute hypoxia.

Objective The aim of this study was to investigate the associations between alleles of the hypoxia-inducible factor 1A (HIF1A) C1772T polymorphism and several physiological responses to hypoxia, including the hypoxic ventilatory response (HVR), and serum erythropoietin (EPO), arterial oxygen saturation (Sao2), and acute mountain sickness (AMS) responses during 8 hours of exposure to normobaric hypoxia. Methods A total of 76 males participated in the study; 52 participants completed an 8-hour exposure to 12.7% oxygen, during which time Sao2, EPO concentrations, and AMS scores were measured, while 62 individuals took part in an HVR trial (in total 38 individuals completed both protocols). DNA was obtained from leukocytes, and a 346-bp fragment of the HIF1A gene containing the C1772T polymorphism was amplified using polymerase chain reaction. Fragments were sequenced to reveal individual genotypes, and the associations between HIF1A genotype and EPO, Sao2, AMS responses to hypoxia and HVR were examined. Results The magnitude of the hypoxic responses was highly variable between individuals. The increase in participants' EPO responses ranged from 89% to 388% of baseline values following hypoxia, while Sao2 values during the exposure ranged from 71% to 89%. The HVR ranged from −0.04 to +2.18 L · min−1 · Sao2%−1 among participants. No significant differences in EPO, Sao2, AMS, or HVR results were observed between the HIF1A CC genotype and the combined CT/TT genotype group. Conclusion In this study, the HIF1A C1772T polymorphism does not appear to influence EPO, Sao2, or AMS responses during acute hypoxic exposure, or the magnitude of the HVR.

Activity in Geriatric acute CARe (AGECAR): Rationale, design and methods

The Activity in GEriatric acute CARe (AGECAR) is a randomised control trial to assess the effectiveness of an intrahospital strength and walk program during short hospital stays for improving functional capacity of patients aged 75 years or older. Patien

Genetic predisposition to acute respiratory distress syndrome in patients with severe sepsis

The objective of this study was to analyze the association between candidate gene polymorphisms and susceptibility to acute respiratory distress syndrome (ARDS) in patients with severe sepsis. Patients older than 18 years admitted to the intensive care un

Prediction of 30-day mortality in older patients with a first acute myocardial infarction

This study sought predictors of mortality in patients aged >or=75 years with a first ST-segment elevation myocardial infarction (STEMI) and evaluated the validity of the GUSTO-I and TIMI risk models. Clinical variables, treatment and mortality data from 433 consecutive patients were collected. Univariable and multivariable logistic regression analyses were applied to identify baseline factors associated with 30-day mortality. Subsequently a model predicting 30-day mortality was created and compared with the performance of the GUSTO-I and TIMI models. After adjustment, a higher Killip class was the most important predictor (OR 16.1; 95% CI 5.7-45.6). Elevated heart rate, longer time delay to admission, hyperglycemia and older age were also associated with increased risk. Patients with hypercholesterolemia had a significantly lower risk (OR 0.46; 95% CI 0.24-0.86). Discrimination (c-statistic 0.79, 95% CI 0.75-0.84) and calibration (Hosmer-Lemeshow 6, p = 0.5) of our model were good. The GUSTO-I and TIMI risk scores produced adequate discrimination within our dataset (c-statistic 0.76, 95% CI 0.71-0.81, and c-statistic 0.77, 95% CI 0.72-0.82, respectively), but calibration was not satisfactory (HL 21.8, p = 0.005 for GUSTO-I, and HL 20.6, p = 0.008 for TIMI). In conclusion, short-term mortality in elderly patients with a first STEMI depends most importantly on initial clinical and hemodynamic status. The GUSTO-I and TIMI models are insufficiently adequate for providing an exact estimate of 30-day mortality risk.

Influence of acute vitamin C and/or carbohydrate ingestion on hormonal, cytokine, and immune responses to prolonged exercise

Davison, G. and Gleeson, M. (2005). Influence of Acute Vitamin C and/or Carbohydrate Ingestion on Hormonal, Cytokine, and Immune Responses to Prolonged Exercise. International Journal of Sport Nutrition and Exercise Metabolism. 15(5), pp.465-479 RAE2008

FLT3-driven redox signalling in acute myeloid leukaemia

Acute myeloid leukaemia refers to cancer of the blood and bone marrow characterised by the rapid expansion of immature blasts of the myeloid lineage. The aberrant proliferation of these blasts interferes with normal haematopoiesis, resulting in symptoms such as anaemia, poor coagulation and infections. The molecular mechanisms underpinning acute myeloid leukaemia are multi-faceted and complex, with a range of diverse genetic and cytogenetic abnormalities giving rise to the acute myeloid leukaemia phenotype. Amongst the most common causative factors are mutations of the FLT3 gene, which codes for a growth factor receptor tyrosine kinase required by developing haematopoietic cells. Disruptions to this gene can result in constitutively active FLT3, driving the de-regulated proliferation of undifferentiated precursor blasts. FLT3-targeted drugs provide the opportunity to inhibit this oncogenic receptor, but over time can give rise to resistance within the blast population. The identification of targetable components of the FLT3 signalling pathway may allow for combination therapies to be used to impede the emergence of resistance. However, the intracellular signal transduction pathway of FLT3 is relatively obscure. The objective of this study is to further elucidate this pathway, with particular focus on the redox signalling element which is thought to be involved. Signalling via reactive oxygen species is becoming increasingly recognised as a crucial aspect of physiological and pathological processes within the cell. The first part of this study examined the effects of NADPH oxidase-derived reactive oxygen species on the tyrosine phosphorylation levels of acute myeloid leukaemia cell lines. Using two-dimensional phosphotyrosine immunoblotting, a range of proteins were identified as undergoing tyrosine phosphorylation in response to NADPH oxidase activity. Ezrin, a cytoskeletal regulatory protein and substrate of Src kinase, was selected for further study. The next part of this study established that NADPH oxidase is subject to regulation by FLT3. Both wild type and oncogenic FLT3 signalling were shown to affect the expression of a key NADPH oxidase subunit, p22phox, and FLT3 was also demonstrated to drive intracellular reactive oxygen species production. The NADPH oxidase target protein, Ezrin, undergoes phosphorylation on two tyrosine residues downstream of FLT3 signalling, an effect which was shown to be p22phox-dependent and which was attributed to the redox regulation of Src. The cytoskeletal associations of Ezrin and its established role in metastasis prompted the investigation of the effects of FLT3 and NADPH oxidase activity on the migration of acute myeloid leukaemia cell lines. It was found that inhibition of either FLT3 or NADPH oxidase negatively impacted on the motility of acute myeloid leukaemia cells. The final part of this study focused on the relationship between FLT3 signalling and phosphatase activity. It was determined, using phosphatase expression profiling and real-time PCR, that several phosphatases are subject to regulation at the levels of transcription and post-translational modification downstream of oncogenic FLT3 activity. In summary, this study demonstrates that FLT3 signal transduction utilises a NADPH oxidase-dependent redox element, which affects Src kinase, and modulates leukaemic cell migration through Ezrin. Furthermore, the expression and activity of several phosphatases is tightly linked to FLT3 signalling. This work reveals novel components of the FLT3 signalling cascade and indicates a range of potential therapeutic targets.