Activating plant immunity: the hidden dance of intracellular Ca2+ stores

Calcium ion (Ca2+) serves as a versatile and conserved second messenger in orchestrating immune responses. In plants, plasma membrane-localized Ca2+-permeable channels can be activated to induce Ca2+ influx from extracellular space to cytosol upon pathogen infection. Notably, different immune elicitors can induce dynamic Ca2+ signatures in the cytosol. During pattern-triggered immunity, there is a rapid and transient increase in cytosolic Ca2+, whereas in effector-triggered immunity, the elevation of cytosolic Ca2+ is strong and sustained. Numerous Ca2+ sensors are localized in the cytosol or different intracellular organelles, which are responsible for detecting and converting Ca2+ signals. In fact, Ca2+ signaling coordinated by cytosol and subcellular compartments plays a crucial role in activating plant immune responses. However, the complete Ca2+ signaling network in plant cells is still largely ambiguous. This review offers a comprehensive insight into the collaborative role of intracellular Ca2+ stores in shaping the Ca2+ signaling network during plant immunity, and several intriguing questions for future research are highlighted.

[Acidophil stem cell pituitary neuroendocrine tumors/adenoma: a clinicopathological analysis of five cases]

Objective: To investigate the clinicopathological characteristics of acidophil stem cell pituitary neuroendocrine tumors (PitNET)/adenoma. Methods: Five cases of acidophil stem cell PitNET/adenoma were diagnosed between May 2022 and July 2023 at the Second Hospital of Hebei Medical University, Shijiazhuang, China. The clinicopathological features of the tumor were analyzed by using histology, immunohistochemistry, and electron microscopy. The relevant literature was reviewed. Results: There were 1 male and 4 females, aged from 23 to 69 years. Patient 3 was 55 years old at the time of diagnosis and first surgery, and relapsed 5 years later. The patients' median age was 32 years. Patients 1 and 5 showed elevated blood prolactin, with various degrees of hormonal symptoms except Patient 3, who showed only tumor compression symptoms. Imaging studies showed that all cases involved the sellar floor. The tumors of Patients 1, 2 and 5 were closely related to the cavernous sinus segment of the internal carotid artery. The tumors exhibited a diffuse growth pattern with chromophobic to slightly acidophilic cytoplasm. A few of tumor cells showed chromophobic cytoplasm. The nucleoli were conspicuous. Intranuclear inclusion bodies and variably-sized clear vacuoles were observed occasionally. Under electron microscope, marked mitochondrial abnormalities were observed, including increased mitochondria number, expanded hypertrophy, and absence of mitochondrial ridge fracture. Some mitochondrial matrices were dense, while some were vacuolated. Conclusions: Acidophil stem cell PitNET/adenoma is a rare type of pituitary adenomas/PitNETs. It often has a more clinically aggressive manner with immature cells, diffuse expression of PIT1, prolactin, and varying degrees of growth hormone expression. Because of the obvious diversity of their clinical hormone status and hormone immune expression, the diagnosis of this type tumor is still a challenge.

Elevated carbon dioxide concentrations increase the risk of Cd exposure in rice

Since the Industrial Revolution, crops have been exposed to various changes in the environment, including elevated atmospheric carbon dioxide (CO2) concentration and cadmium (Cd) pollution in soil. However, information about how combined changes affect crop is limited. Here, we have investigated the changes of japonica and indica rice subspecies seedlings under elevated CO2 level (1200 ppm) and Cd exposure (5 μM Cd) conditions compared with ambient CO2 level (400 ppm) and without Cd exposure in CO2 growth chambers with hydroponic experiment. The results showed that elevated CO2 levels significantly promoted seedling growth and rescued the growth inhibition under Cd stress. However, the elevated CO2 levels led to a significant increase in the shoot Cd accumulation of the two rice subspecies. Especially, the increase of shoot Cd accumulation in indica rice was more than 50% compared with control. Further investigation revealed that the decreases in the photosynthetic pigments and photosynthetic rates caused by Cd were attenuated by the elevated CO2 levels. In addition, elevated CO2 levels increased the non-enzymatic antioxidants and significantly enhanced the ascorbate peroxidase (APX) and glutathione reductase (GR) activities, alleviating the lipid peroxidation and reactive oxygen species (ROS) accumulation induced by Cd. Overall, the research revealed how rice responded to the elevated CO2 levels and Cd exposure, which can help modify agricultural practices to ensure food security and food safety in a future high-CO2 world.

Genetically Engineered Mouse Models of CIC-DUX4 Sarcoma Reveal an Unexpected Sensitivity to Histone Deacetylase (HDAC) Inhibition

PURPOSE/OBJECTIVE(S)

Undifferentiated small round cell sarcomas constitute a highly aggressive subtype of soft tissue sarcoma that affects adolescents and young adults. Frequently, these cancers are caused by a gene fusion between the DNA binding domain of capicua (CIC), a canonical tumor suppressor that normally acts as a transcriptional repressor, with the transcriptional activation domain of double homeobox 4 (DUX4). Given the rare nature of CIC-DUX4 sarcoma (CDS), obtaining patient tissues to study the mechanisms of disease is very challenging. Moreover, conducting clinical trials to identify radiosensitizers or other novel treatments is not possible underscoring the need for a primary animal model. Here, we report the development and characterization of the first genetically engineered mouse model of CDS and the use of this model to investigate novel therapies.

MATERIALS/METHODS

Using Cre-loxP technology, three genetically engineered mouse models of CDS were developed. The resulting tumors were characterized by hematoxylin and eosin (H&E) staining, immunohistochemistry (IHC), and RNA-sequencing. Cell lines from multiple primary and metastatic tumors were derived and used for Chromatin Immunoprecipitation (ChiP) sequencing, Rapid Immunoprecipitation mass spectrometry of Endogenous proteins (RIME), and targeted drug screening.

RESULTS

In all three models, spontaneous (Cre-independent) recombination occurred in chimeric animals resulting in the formation of soft tissue tumors, widespread metastasis to the lungs, liver, and brain, and 100% lethality within 4-8 weeks of life. The tumors histologically resembled human CDS and stained positive for an HA (hemagglutinin) epitope tag confirming transgene expression. Of 108 chimeric pups (generation 0, G0), only one male bred before succumbing to metastatic disease. G2 progeny now exhibit resistance to spontaneous recombination and tumor development enabling reliable propagation of one of the models for experimentation. Using tumor derived cell lines for integrative analyses of multi-omics datasets, we find evidence for a model where CIC-DUX4 functions as a neomorphic and oncogenic transcriptional activator, which cooperates with ETS family transcription factors to drive the CDS transcriptional program. Lastly, small molecule epigenetic drug screens in mouse and human CDS cell lines point to an unexpected sensitivity to HDAC inhibitors, which we hypothesize may be attributable to ETS factor hyperactivity.

CONCLUSION

Genetically engineered mouse models of CIC-DUX4 sarcoma form tumors that recapitulate the human disease. Using mouse tumors and tumor-derived cell lines, we identify a mechanistic role and potential therapeutic vulnerability that converges on the ETS family transcription factors.

Sulfur reduces the root-to-shoot translocation of arsenic and cadmium by regulating their vacuolar sequestration in wheat (Triticum aestivum L.)

Accumulation of arsenic (As) and cadmium (Cd) in wheat grain is a serious threat to human health. Sulfur (S) can simultaneously decrease wheat grain As and Cd concentrations by decreasing their translocation in wheat; however, the mechanisms are unclear. We conducted hydroponic experiments to explore the mechanisms by which S modulates As and Cd translocation and their toxicity in wheat. Wheat seedlings were grown in deficient sulfate (2.5 µM) or sufficient sulfate (1.0 mM) nutrient solutions for 6 days and then exposed to zero (control), low As+Cd (1 µM As plus 0.5 µM Cd), or high As+Cd (50 µM As plus 30 µM Cd) for another 6 days. Compared with the control, plant growth was not affected by low As+Cd, but was significantly inhibited by high As+Cd. In the low As+Cd treatment, S supply had no significant effect on plant growth or root-to-shoot As and Cd translocation. In the high As+Cd treatment, sufficient S supply significantly alleviated As and Cd toxicity and their translocation by increasing phytochelatin (PC) synthesis and the subsequent vacuolar sequestration of As and Cd in roots, compared with deficient S supply. The use of _L-buthionine sulfoximine (a specific inhibitor of γ-glutamylcysteine synthetase) confirmed that the alleviation of As and Cd translocation and toxicity in wheat by S is mediated by increased PC production. Also, TaHMA3 gene expression in wheat root was not affected by the As+Cd and S treatments, but the expression of TaABCC1 was upregulated by the high As+Cd treatment and further increased by sufficient S supply and high As+Cd treatment. These results indicate that S-induced As and Cd subcellular changes affect As and Cd translocation mainly by regulating thiol metabolism and ABCC1 expression in wheat under As and Cd stress.

Long term application of plant growth-promoting bacterium improved grain weight and reduced arsenic accumulation in rice grain: A comparison of 10 bacteria

Rice (Oryza sativa L.) is one of the main food crops, it plays an important role in the human diet. Arsenic (As) contamination in paddy soil inhibits rice growth and reduces rice yield seriously. In addition, As accumulated in rice grains was harmful to human health through the food chain. Using the exogenous method to alleviate As stress and reduce As accumulation in rice grain is one of the potential ways to achieve food safety in polluted farmland. In the present study, 10 bacteria was applied to evaluate the effects of plant growth-promoting bacteria (PGPBs) on rice growth and As accumulation in rice grain. The results showed higher levels of As inhibited PGPB growth, the most tolerant and sensitive bacteria were Bj05 and Ls09, with the growth reduction of 16.9% and 96.7% under 50 mM As, respectively. Most of 10 PGPBs enhanced rice growth and improved rice grain weight under As exposure, among them, Ts06 showed the most effective one. Six of 10 PGPBs reduced rice grain As levels significantly, the highest reduction of grain As was observed in Ts06 inoculated rice, with grain As deceasing to 46.3% of the control. Bj05 was the only one which caused the increase in grain As of Yangdao 6. The Pearson correlation analysis showed grain As concentration negatively correlated with leave As concentration, while did not correlated with total As accumulated in shoot, and soil available As and P. The present results indicated that some PGPBs inhibited As translocation from leave to grain, thus reduced As accumulation in rice grain. Ts06 was suggested to be a candidate as microbial amendments for As-contaminated paddy fields.

Transcript expression profiling of fibromelanosis-related genes in black-bone chickens

1. The aim of the present study was to identify differentially expressed genes (DEGs) and metabolic pathways involved in this phenotype. Fibromelanosis is the most striking feature of black-bone chickens, such as the Silkie and Dongxiang indigenous breeds. Due to the accumulation of eumelanin in connective tissues, fibromelanosis manifests as black colouration of the skin, muscles, gut, and periosteum. Studies on fibromelanosis can provide useful information pertaining to human diseases and offer commercial value to the poultry industry. However, the genetic basis of fibromelanosis remains unclear.2. Digital gene expression analysis was performed on black and white skin samples collected from the HW1 black-bone chicken line to detect differences in genome-wide expression patterns. A total of >30 billion bp were sequenced, and 2,707,926,466 bp and 2,948,782,964 bp of clean data obtained for creation of libraries for black and white skin, respectively. In total, 252 DEGs from 15,508 mapped genes were identified with 83 up-regulated in white skin and 169 up-regulated in black skin.3. Gene ontology analysis highlighted that genes from the extracellular region and associated components were abundant among the DEGs. Pathway analysis revealed that many DEGs were linked to amino acid metabolism and the immune system. qRT-PCR validation using 14 genes showed good conformity with the sequence analysis of fibromelanosis-related genes.4. The results showed that L-dopachrometautomerase precursor (DCT), tyrosine aminotransferase (TAT), 4-hydroxyphenylpyruvate dioxygenase (HPD) from the tyrosine metabolism pathway, coagulation factor II (F2), fibrinogen beta chain (FGB), plasminogen (PLG) and complement component 7 (C7) from the complement and coagulation cascades were important genes in the fibromelanosis process in black-bone chickens. These candidate genes require further correlation analysis and functional verification.

Identification of a plant endophytic growth-promoting bacteria capable of inhibiting cadmium uptake in rice

AIMS

The study aims to identify a novel plant growth-promoting bacteria (PGPB), which contributes to promoting growth and reducing cadmium (Cd) concentration in rice under Cd-contaminated conditions.

METHODS AND RESULTS

Nine bacterial strains were isolated from plants grown in Cd-contaminated soil. These bacteria were tolerant to 1000 μmol/L CdCl₂ , capable of producing indole-3-acetic acid, fixing nitrogen and solubilizing phosphate. The result of hydroponic experiment showed that under the control and Cd stress conditions, the dry weight of the Tm02-inoculated rice seedlings increased significantly. Furthermore, under Cd stress, the concentration of Cd in the shoot of the Tm02-inoculated seedlings decreased significantly, while there was no significant difference in Cd concentration between treatment with other eight strains and noninoculated seedlings. The same results were observed in the pot experiment as well, where there was a significantly reduced Cd concentration in rice grains of the Tm02-inoculated rice plants. Tm02 was classified as Pantoea agglomerans through 16S rDNA sequencing.

CONCLUSIONS

A novel PGPB strain Tm02 was identified and confirmed that it has the function of promoting rice growth and reducing Cd concentration in rice grain under Cd-contaminated conditions. This strain has the potential to improve rice yield in Cd-contaminated paddy fields.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study provides a new example of using PGPB to improve the tolerance of rice to Cd pollution.

Promotion of growth and phytoextraction of cadmium and lead in Solanum nigrum L. mediated by plant-growth-promoting rhizobacteria

Plant growth-promoting rhizobacteria (PGPR) are a specific category of microbes that improve plant growth and promote greater tolerance to metal stress through their interactions with plant roots. We evaluated the effects of phytoremediation combining the cadmium accumulator Solanum nigrum L. and two Cd- and Pb-resistant bacteria isolates. To understand the interaction between PGPR and their host plant, we conducted greenhouse experiments with inoculation treatments at Nanjing Agricultural University (Jiangsu Province, China), in June 2018. Two Cd- and Pb-resistant PGPR with various growth-promoting properties were isolated from heavy metal-contaminated soil. 16S rRNA analyses indicated that the two isolates were Bacillus genus, and they were named QX8 and QX13. Pot experiments demonstrated that inoculation may improve the rhizosphere soil environment and promote absorption of Fe and P by plants. Inoculation with QX8 and QX13 also enhanced the dry weight of shoots (1.36- and 1.7-fold, respectively) and roots (1.42- and 1.96-fold) of plants growing in Cd- and Pb-contaminated soil, and significantly increased total Cd (1.28-1.81 fold) and Pb (1.08-1.55 fold) content in aerial organs, compared to non-inoculated controls. We also detected increases of 23% and 22% in the acid phosphatase activity of rhizosphere soils inoculated with QX8 and QX13, respectively. However, we did not detect significant differences between inoculated and non-inoculated treatments in Cd and Pb concentrations in plants and available Cd and Pb content in rhizosphere soils. We demonstrated that PGPR-assisted phytoremediation is a promising technique for remediating heavy metal-contaminated soils, with the potential to enhance phytoremediation efficiency and improve soil quality.

Ectopic expression of wheat aquaglyceroporin TaNIP2;1 alters arsenic accumulation and tolerance in Arabidopsis thaliana

Arsenic (As) is one of the most toxic contaminants to food crops, and as such, decreasing crops uptake and accumulation of As cannot be overemphasized. Here, we characterized a functional wheat NIP2;1 homolog of the As transporter, TaNIP2;1. TaNIP2;1 expression was suppressed by arsenite (As(III)) in wheat. Ectopic expression of TaNIP2;1 in the Δfps1 yeast mutant enhanced yeast sensitivity towards As(III). Conversely, the elevated expression of TaNIP2;1 in Δacr3 mutants decreased yeast sensitivity to arsenate (As(V)), demonstrating that TaNIP2;1 showed both influx and efflux transport activities for As(III) in yeasts. This is further supported by increased As concentration in the yeast cells that overproduce TaNIP2;1 in Δfps1, while As concentration decreased in Δacr3. Furthermore, ectopic expression of TaNIP2;1 in Arabidopsis confirmed that TaNIP2;1 can transport As into plants, as supported by increased sensitivity to and uptake of As(III). No change in plant sensitivity was found to Cu(II), Cd(II), Zn(II) or Ni(II), indicating that transport activity of TaNIP2;1 is specific for As(III). Taken together, our data show that TaNIP2;1 may be involved in As(III) transportation in plants. This finding reveals a functional gene that can be manipulated to reduce As content in wheat.

Sulfate application decreases translocation of arsenic and cadmium within wheat (Triticum aestivum L.) plant

Arsenic (As) and cadmium (Cd) typically exhibit divergent fates in soil, which complicates efforts to decrease As and Cd accumulation in the edible parts of crops. Here, we performed pot experiments to examine the effect of sulfate application on As and Cd accumulation in the grain of wheat grown in contaminated soil. Compared to the control (no sodium sulfate addition), application of 120 mg kg^-1 sodium sulfate decreased the rhizosphere soil pH from 7.27 to 7.10 and increased the soil extractable Cd concentration; however, it did not significantly influence the soil extractable As concentration. However, sodium sulfate addition decreased As and Cd concentrations in wheat grain, in association with decreased As and Cd translocation from root and straw to grain, rather than from soil to root. Furthermore, sodium sulfate addition significantly decreased membrane lipid peroxidation and enhanced photosynthesis, while increasing the uptake of nitrogen, phosphorus, and sulfur. These effects increased the growth and grain weight of plants grown in As and Cd co-contaminated soil. Our findings provide insight into the mechanisms by which sulfate modulates As and Cd uptake and translocation in wheat; moreover, our findings will enable formulation of strategies to decrease As and Cd concentrations in the grain of wheat grown in As and Cd co-contaminated soil.

Full-Length Transcriptome Assembly of Italian Ryegrass Root Integrated with RNA-Seq to Identify Genes in Response to Plant Cadmium Stress

Cadmium (Cd) is a toxic heavy metal element. It is relatively easily absorbed by plants and enters the food chain, resulting in human exposure to Cd. Italian ryegrass (Lolium multiflorum Lam.), an important forage cultivated widely in temperate regions worldwide, has the potential to be used in phytoremediation. However, genes regulating Cd translocation and accumulation in this species are not fully understood. Here, we optimized PacBio ISO-seq and integrated it with RNA-seq to construct a de novo full-length transcriptomic database for an un-sequenced autotetraploid species. With the database, we identified 2367 differentially expressed genes (DEGs) and profiled the molecular regulatory pathways of Italian ryegrass with Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis in response to Cd stress. Overexpression of a DEG LmAUX1 in Arabidopsis thaliana significantly enhanced plant Cd concentration. We also unveiled the complexity of alternative splicing (AS) with a genome-free strategy. We reconstructed full-length UniTransModels using the reference transcriptome, and 29.76% of full-length models had more than one isoform. Taken together, the results enhanced our understanding of the genetic diversity and complexity of Italian ryegrass under Cd stress and provided valuable genetic resources for its gene identification and molecular breeding.

Influence of PGPB Inoculation on HSP70 and HMA3 Gene Expression in Switchgrass under Cadmium Stress

This study aimed to evaluate the gene expression of HSP70 and HMA3 in the switchgrass inoculated with plant-growth-promoting-bacteria (PGPB) under cadmium (Cd) stress and to observe the benefit of PGPB in plant growth and development. Plants were grown in hydroponic culture and treated with PGPB inoculants: Pseudomonas grimontii, Pantoea vagans, Pseudomonas veronii, and Pseudomonas fluorescens with the strains Bc09, So23, E02, and Oj24, respectively. The experimental results revealed that HSP70 and HMA3 genes expressed highly in the PGPB-inoculated plants under Cd stress. In addition, the expression of HSP70 and HMA3 genes was considerably higher in the first two days after successive four-day exposure of Cd in plants compared to the last two days of exposure. Increased biomass and indole-3-acetic-acid production with reduced Cd accumulation were observed in the PGPB-inoculated plants under Cd stress compared to the Cd-control plants. These PGPB, with their beneficial mechanisms, protect plants by modifying the gene expression profile that arises during Cd-toxic conditions and increased the healthy biomass of switchgrass. This demonstrates there is a correlation among the growth parameters under Cd stress. The PGPB in this study may help to intensify agriculture by triggering mechanisms to encourage plant growth and development under heavy metal stress.

Low arsenate influx rate and high phosphorus concentration in wheat (Triticum aestivum L.): A mechanism for arsenate tolerance in wheat plants

Two wheat (Triticum aestivum L.) cultivars differing in arsenic (As)-tolerance were used to investigate the effects of phosphorus (P) concentration and nutrient solution pH on As(V) toxicity and As(V) uptake kinetics, and to illustrate the mechanism of As(V) tolerance in wheat seedlings. Low pH and low phosphate concentration enhanced wheat uptake of As, resulting in high As toxicity. The As(V)-tolerant cultivar MM45 exhibited higher relative root elongation than non-tolerant cultivar HM29 in all treatments, except that no genotypic difference was recorded for the solution P at 100 μmol L^-1 or greater. Wheat seedling As(V) tolerance was positively correlated with P concentration in roots and shoots. In short-term (30 min) As(V)-uptake kinetics experiments, the maximum influx rate (V_max) of As(V) increased with decreasing solution pH (from 7.0 to 6.0). Compared with HM29, although MM45 had lower V_max, its Michaelis-Menten constant (K_m) did not exceed that of HM29 in all treatments. The V_max values of both cultivars were not significantly affected by phosphate treatments, except for HM29 which had significantly higher V_max value in the presence of phosphate at pH 7.0. The K_m values of the two cultivars increased by 9- to 20-fold when phosphate was present as opposed to absent from the uptake solution. This study showed that the V_max values are mainly increased by high pH and As(V) uptake K_m is mainly increased by phosphate presence. Decreased As(V) influx rates during early stages and increased P concentration in plant tissues are associated with increased As tolerance in wheat seedlings.

Transcriptome analysis of Cd-treated switchgrass root revealed novel transcripts and the importance of HSF/HSP network in switchgrass Cd tolerance

Transcriptome analysis of Cd-treated switchgrass roots not only revealed novel switchgrass transcripts and gene structures but also highlighted the indispensable role of HSF/HSP network in switchgrass Cd tolerance. Switchgrass (Panicum virgatum L.), a C4 perennial tall grass, can be used for revegetation of Cd-contaminated soil. In the present study, a comparative transcriptome analysis of Cd-treated switchgrass roots was conducted. The result revealed a total of 462 novel transcripts and refined gene structures of 2337 transcripts. KEGG pathway and Gene Ontology analyses of the differentially expressed genes (DEGs) suggested that activation of redox homeostasis and oxidation-related metabolic processes were the primary response to Cd stress in switchgrass roots. In particular, 21 out of 23 differentially expressed shock transcription factor genes (HSFs), and 22 out of 23 differentially expressed heat shock protein genes (HSPs) had increased expression levels after Cd treatment. Furthermore, over-expressing one HSP-encoding gene in Arabidopsis significantly improved plant Cd tolerance. The result highlighted the activation of the redox homeostasis and the involvement of the HSF/HSP network in re-establishing normal protein conformation and thus cellular homeostasis in switchgrass upon Cd stress. These DEGs, especially those of the HSF/HSP network, could be used as candidate genes for further functional studies toward improved plant Cd tolerance in switchgrass and related species.

[Effect of intratympanic injection of budesonide for otitis media with effusion in adolescents and adults]

Objective:To assess the longitudinal curative effect and improvement of subjective symptoms by using intratympanic injection of budesonide (BUD) for OME patients over 12 years old and adults.Method:One hundred and eighty patients who were diagnosed as OME were recruited. A single-blind, randomized, parallel-control prospective study was performed. Dexamethasone (DEX) and sodium chloride (NS) were served as controls. The patients were randomly assigned into three groups, which respectively received intratympanic injection of BUD (0.5 mg/ml), DEX (5 mg/ml) or 0.9% NS solution (1 ml) once a week. Survival analysis was applied to compare the longitudinal curative effect among the three groups. Meanwhile, seven main subjective symptoms were scored by 10-point visual scale (VAS) and physician's evaluations were preformed during treatment and follow-up.Result:After adjustement for course of disease, volume and characters of effusion, the relative risk (RR) of BUD was 0.131 (95%CI: 0.053-0.354) when compared with NS. Survival curve showed, in BUD group, about 96.6%(57/59) of patients maintained effectiveness more than 3 months, 83.1%(49/59) were more than 1 year, and 81.4%(48/59) of the patients could sustain longer than 3 years. In DEX group, 73.2%(41/56) of patients showed effectiveness more than 3 months, 46.4%(26/56) were more than 1 year, and 42.9%(24/56) of the patients could sustain longer than 3 years. While in NS group, 50.8%(33/65) of the patients showed effectiveness more than 3 months, 26.2% (17/65) were more than 1 year, and 20.0%(13/65) of the patients could sustain longer than 3 years. Survival curve demonstrated that the rank of longitudinal therapeutic efficacy was BUD, DEX and NS (P< 0.05). Both BUD and DEX showed improvements in subjective symptoms and quality of life (except for mental stress) compared with NS (P< 0.05). In the aspect of improving the symptom of stuffy ear, BUD showed advantage over both DEX and NS. During and after treatment, no serious complications or sequelae were observed.Conclusion:Intratympanic injection with BUD for OME patients showed advantages in improving long-term therapeutic efficacy, it was a safe as well as effective intervention for children over age of 12 and adults suffering from OME.

Do aeration conditions affect arsenic and phosphate accumulation and phosphate transporter expression in rice (Oryza sativa L.)?

Widespread contamination of rice with arsenic (As) has revealed a major exposure pathway to humans. The present study aimed to investigate the effects of oxygen in the rhizosphere on phosphate (P) transporter (for arsenate transportation) expressions, on As and P accumulation and As speciation in four rice genotypes. Oxygenation marginally increased root and shoot length. Total As concentrations in rice roots were dramatically reduced following aeration compared to stagnant treatments (p < 0.001). Aeration treatments significantly increased arsenate while reducing arsenite concentrations in roots (p < 0.001). Root arsenite concentrations were 1.5-2.5 times greater in stagnant than in aeration treatments. Total P concentrations in rice roots were dramatically increased following aeration compared to stagnant treatments. The relative abundance of phosphate transporter (inorganic phosphate transporter and phosphate/H⁺ symporter family protein) expressions showed downregulation in aeration treatments, particularly for SY-9586, XWX-17, and XWX-12 in inorganic phosphate transporter expressions and XWX-17 in phosphate/H⁺ symporter family protein expression (p < 0.05). The relative abundance of phosphate carrier protein expressions were relatively higher than the other phosphate transporters, showing upregulation in aeration treatments.

Comparative study of Cd uptake and tolerance of two Italian ryegrass (Lolium multiflorum) cultivars

Cadmium (Cd) is one of the most toxic heavy metals and is difficult to be removed from contaminated soil and water. Italian ryegrass (Lolium multiflorum), as an energy crop, exhibits a valuable potential to develop Cd polluted sites due to its use as a biofuel rather than as food and forage. Previously, via a screening for Cd-tolerant ryegrass, the two most extreme cultivars (IdyII and Harukaze) with high and low Cd tolerance during seed germination, respectively, were selected. However, the underlying mechanism for Cd tolerance was not well investigated. In this study, we comparatively investigated the growth, physiological responses, and Cd uptake and translocation of IdyII and Harukaze when the seedlings were exposed to a Cd (0–100 μM) solution for 12 days. As expected, excess Cd inhibited seedling growth and was accompanied by an accumulation of malondialdehyde (MDA) and reduced photosynthetic pigments in both cultivars. The effects of Cd on the uptake and translocation of other nutrient elements (Zn, Fe, Mn and Mg) were dependent on Cd concentrations, cultivars, plant tissues and elements. Compared with Harukaze, IdyII exhibited better performance with less MDA and higher pigment content. Furthermore, IdyII was less efficient in Cd uptake and translocation compared to Harukaze, which might be explained by the higher non-protein thiols content in its roots. Taken together, our data indicate that IdyII is more tolerant than Harukaze, which partially resulted from the differences in Cd uptake and translocation.

Exogenous GR24 Alleviates Cadmium Toxicity by Reducing Cadmium Uptake in Switchgrass (Panicum virgatum) Seedlings

Strigolactones (SLs) are classified into plant hormones, playing a key role as a mediator of plant growth in response to several abiotic stresses, including drought and salinity. However, the role of SLs in cadmium (Cd)-induced stress to plants is still unknown. The physiological responses of switchgrass (Panicum virgatum) stressed in 10 μmol L⁻¹ Cd to exogenous synthetic SLs analog, GR24 were studied in hydroponics. The Cd stress significantly caused the adverse effects on plant growth and root morphology, inhibited photosynthesis, but boosted lipid peroxidation of Switchgrass seedlings. After treatment of 1 μmol L⁻¹ GR24, the above adverse effects caused by Cd stress were significantly alleviated, mainly reflects in improvement of shoot biomass, relative water content, root development, chlorophyll contents, activities of typical antioxidant enzymes, nutrient uptake. The reason for exogenous GR24 alleviating cadmium toxicity might be owing to that exogenous GR24 promoted the content of endogenous SLs, increased some essential element Fe (iron), Zn (zinc), Mn (manganese) and Cu (copper) uptake and reduced cadmium uptake, accumulation and partition in shoot of switchgrass seedlings.

[Modified radical mastoidectomy on"drum sinus" type chronic suppurative otitis media:our experience]

Objective:To our experience of modified radical mastoidectomy on "drum sinus" type chronic suppurative otitis media.Method:We measured the size of tympanic sinus,the extent of meningeal plate lowering and the extent of sigmoid ante-displacement in 54 patients of chronic suppurative otitis media,and determined the criterion of "drum sinus".The patients who comply with the criterion received modified radical mastoidectomy and tympanoplasty via epitympanum approach.The patients were followed up for at least 3 months,The time of dry ear,growth of repaired tympanic membrane,and any complications such as dizziness,facial paralysis,cerebrospinal fluid leakage were recorded.Result:Twenty-nine out of the 54 CSOM patients complied with the criterion of drum sinus.Two cases were lost to follow-up.Therefore,27 cases were included in the study.Three months after the operation,the rate of dry ear was 81.5% Tympanic membrane was successfully repaired in 77.8% of the patients.Three cases had dizziness after operation.No facial paralysis or cerebrospinal fluid leakage was observed.Conclusion:For"drum sinus" type chronic suppurative otitis media,the modified radical mastoidectomy and tympanoplasty via epitympanum approach can be taken.

Effects of silicon (Si) on arsenic (As) accumulation and speciation in rice (Oryza sativa L.) genotypes with different radial oxygen loss (ROL)

Arsenic (As) contamination of paddy soils has adversely affected the health of millions of people those consuming rice for staple food. The present study was aimed at investigating the effects of silicon (Si) fertilization on As uptake, speciation in rice plants with different radial oxygen loss (ROL). Six genotypes were planted in pot soils under greenhouse conditions until late tillering state. The results showed that the rates of ROL were higher in hybrid rice genotypes varying from 19.76 to 27 μmol O2 g(-1) root dry weight h(-1) than that in conventional indica rice genotypes varying from 9.55 to 15.41 μmol O2 g(-1) root dry weight h(-1). Si addition significantly increased straw biomass (p<0.005), but with no significant effects on root biomass. Si fertilization significantly reduced shoot and root total As concentrations (p<0.001) in six genotypes grown in 40 mg As/kg soil. Si addition decreased the inorganic As in shoots of 'Xiangfengyou-9' with lower ROL and 'Xiangwanxian-12' with higher ROL by 31% and 25% respectively and had the tendency to increase DMA concentrations. It is potential to reduce As contamination of rice efficiently by combining Si fertilization and selecting genotypes with high radial oxygen loss.

The correlation between MR diffusion-weighted imaging and pathological grades on glioma

OBJECTIVE

This work intends to quantitatively analyze on pathological grade of glioma using Magnetic Resonance (MR) diffusion weighted imaging (DWI) and exploring the relativity of pathological grade and Apparent Diffusion Coefficient (ADC) value of MR diffusion weighted imaging.

PATIENTS AND METHODS

40 patients with glioma accepted the MR diffusion weighted imaging to measure the ADC value of tumor with 3.0T MR machine before the surgery. Tumor samples were sent for pathologic diagnosis and tumor cell density measurement after the operation. The acquired data were analyzed statistically.

RESULTS

The ADC values of low-grade (WHO I-II) glioma were higher than that of high-grade (WHO III-IV), but the cell density of low-grade glioma was apparently lower than that of high-grade glioma. The ADC values and density of tumor cells were negatively correlated with WHO malignant grades, while the density of cells of glioma was positively correlated with WHO malignant grades.

CONCLUSIONS

MR diffusion weighted imaging is an objective and effective examination method.

Processing of facial expressions of emotions in healthy volunteers: an exploration with event-related potentials and personality traits

AIMS OF THE STUDY

Previous studies have shown that event-related potentials (ERPs) are modulated by anxiety or psychopathic personality traits. Therefore, we hypothesized that the automatic processing of facial expressions of emotions (FEE) is also correlated with related disordered personality traits.

METHODS

Thirty-seven healthy volunteers underwent both an "oddball" ERP recording to facial expressions of Anger, Happiness, Sadness, and Neutral, and a test of the Dimensional Assessment of Personality Pathology (DAPP).

RESULTS

Mean reaction time was longer in response to anger than to other facial expressions. Facial expressions of Anger, Happiness and Sadness did not affect N1 (N170). By contrast, Happiness elicited a delayed P2, Anger elicited both a smaller N2 and a delayed P3b, and both Happiness and Anger elicited a P3b of higher amplitude. In addition, P3a latencies to Happiness were negatively correlated with DAPP Identity problems, and P3b latencies to Happiness were negatively correlated with DAPP Stimulus seeking, Callousness, Passive aggressivity, and Narcissism.

CONCLUSION

Our study demonstrates that Anger implicitly captures attentional resources, and Happiness triggers more facilitated processing in individuals with dissocial traits.

A selective cytopheretic inhibitory device for use during cardiopulmonary bypass surgery

BACKGROUND

Systemic inflammatory response syndrome (SIRS) can occur in association with cardiopulmonary bypass (CPB) surgery, resulting in multiple organ dysfunction (MOD). Activated neutrophils have been implicated as major inciting factors in this process. Neutrophil-depleting filters incorporated within the extracorporeal blood circuit during CPB have been developed and evaluated, with inconsistent clinical results.

METHODS

A novel, biomimetic, selective cytopheretic device (SCD) was tested in vitro within a blood circuit to assess safety and interactions with blood components and further evaluated ex vivo in a bovine model of CPB surgery during ventricular assist device implantation.

RESULTS

In vitro blood circuit studies demonstrated that the SCD reduces circulating neutrophils while maintaining low rates of hemolysis compared to current leukocyte-reduction filters. In the bovine CPB model, animals without SCD treatment (No SCD) demonstrated an increase in circulating white blood cell (WBC) and neutrophil counts, steadily increasing throughout CPB. SCD with only systemic heparin anticoagulation (SCD-H) acutely reduced neutrophils for the first 2 hrs of CPB, but followed with a greater than 6-fold increase in neutrophil counts. SCD treatment with regional citrate anticoagulation along the SCD circuit (SCD-C) reduced systemic neutrophil counts throughout 4 hrs of CPB despite lower amounts of eluted cells from the SCD. When analyzed for immature neutrophils, the control and SCD-H showed increasing counts at later time-points, not seen in the SCD-C group, suggesting a more complex mechanism of action than simple leukoreduction.

CONCLUSIONS

These results suggest that SCD-C therapy may disrupt the systemic leukocyte response during CPB, leading to improved outcomes for CPB-mediated MOD.

Functional recovery after transplantation of neural stem cells modified by brain-derived neurotrophic factor in rats with cerebral ischaemia

Functional recovery after transplantation of brain-derived neurotrophic factor (BDNF)-modified neural stem cells (NSCs) was evaluated in a rat model of cerebral ischaemia damage induced by temporary middle cerebral artery occlusion (tMCAO). Western blotting and enzyme-linked immunosorbent assay demonstrated upregulated BDNF protein expression by rat embryonic NSCs transfected with the human BDNF gene (BDNF-NSCs). BDNF-NSCs stimulated neurite outgrowth in cocultured dorsal root ganglion neurons, suggesting that BDNF increased neurogenesis in vitro. In vivo, BDNF promoted recovery of tMCAO. Phosphate-buffered saline, untransformed NSCs or BDNF-NSCs were introduced into the penumbra zone of the right striatum of tMCAO rats and neurological function deficit was assessed for up to 12 weeks using the neurological severity score (NSS). The NSS was significantly lower in the BDNF-NSC transfected transplant group than in all the other groups from week 10. BDNF-NSCs recovered 1 week after transplantation expressed BDNF protein. Transplanted NSCs had differentiated into mature neurons 12 weeks after transplantation. Transgenic NSCs have potential as a therapeutic agent for brain ischaemia.

Bioaccumulation of heavy metals by the aquatic plants Potamogeton pectinatus L. and Potamogeton malaianus Miq. and their potential use for contamination indicators and in wastewater treatment

The concentrations of heavy metals in the leaves of two aquatic plants Potamogeton pectinatus L. and Potamogeton malaianus Miq., and the corresponding water and sediment samples from the Donghe River in Jishou City of Hunan Province, China were studied to investigate metal contamination from the intensive industrial activities in the surrounding area. Results showed that the concentrations of heavy metals in the sediments, especially Cd, Mn and Pb, were much higher than the eco-toxic threshold values developed by the U. S. Environmental Protection Agency. Between the two plant species, P. pectinatus showed the higher capacity in metal accumulation. The highest concentrations of Cd, Pb, Cu, Zn and Mn were found in the leaves of P. pectinatus, reaching 596, 318, 62.4, 6590 and 16,000 mg kg(-1) (DW), respectively. Significantly positive relationships were observed among the concentrations of Zn, Cu and Mn in the leaves of both aquatic plants and those in water, indicating the potential use of the two plants for pollution monitoring of these metals. In addition, a laboratory experiment was conducted to investigate the ability of P. pectinatus and P. malaianus to remove heavy metals from contaminated river water. The average removal efficiencies by P. pectinatus and P. malaianus for Cd, Pb, Mn, Zn and Cu from the spiked Donghe River water were 92%, 79%, 86%, 67% and 70%, respectively. The results indicated that P. pectinatus and P. malaianus had high capabilities to remove heavy metals directly from the contaminated water. The potential use of these plants in wastewater treatment is worth further exploration.

Biosynthesis of sphinganine-analog mycotoxins

Sphinganine-analog mycotoxins (SAMT) are polyketide-derived natural products produced by a number of plant pathogenic fungi and are among the most economically important mycotoxins. The toxins are structurally similar to sphinganine, a key intermediate in the biosynthesis of ceramides and sphingolipids, and competitive inhibitors for ceramide synthase. The inhibition of ceramide and sphingolipid biosynthesis is associated with several fatal diseases in domestic animals and esophageal cancer and neural tube defects in humans. SAMT contains a highly reduced, acyclic polyketide carbon backbone, which is assembled by a single module polyketide synthase. The biosynthesis of SAMT involves a unique polyketide chain-releasing mechanism, in which a pyridoxal 5'-phosphate-dependent enzyme catalyzes the termination, offloading and elongation of the polyketide chain. This leads to the introduction of a new carbon-carbon bond and an amino group to the polyketide chain. The mechanism is fundamentally different from the thioesterase/cyclase-catalyzed polyketide chain releasing found in bacterial and other fungal polyketide biosynthesis. Genetic data suggest that the ketosynthase domain of the polyketide synthase and the chain-releasing enzyme are important for controlling the final product structure. In addition, several post-polyketide modifications have to take place before SAMT become mature toxins.

ZD6474 reverses multidrug resistance by directly inhibiting the function of P-glycoprotein

P-glycoprotein (P-gp) pumps multiple types of drugs out of the cell, using energy generated from ATP, and confers multidrug resistance (MDR) on cancer cells. ZD6474 is an orally active, selective inhibitor of the vascular endothelial growth factor receptor, epidermal growth factor receptor, and rearranged during transfection tyrosine kinases. This study was designed to examine whether ZD6474 reverses P-gp-mediated MDR in cancer cells. Here, we show that clinically achievable levels of ZD6474 reverse P-gp-mediated MDR of the P-gp-overexpressing cell lines derived from breast cancer, MCF-7/adriamycin (ADR), and human oral epidermoid carcinoma, KBV200 to ADR, docetaxel, and vinorelbine. This ability to reverse the P-gp-mediated resistance is comparable to that of another frequently used reversal agent known as verapamil. ZD6474 itself moderately inhibits the proliferation of both MCF-7 and MCF-7/ADR cells with almost equal activity, but its inhibitory effect is not altered by co-incubation with verapamil, suggesting that ZD6474 may not be a substrate of P-gp. In addition, ZD6474 increases the intracellular accumulation of the P-gp substrate, rhodamine-123, and ADR, by enhancing the uptake and/or decreasing the efflux of these compounds in resistant cells. Further studies show that ZD6474 stimulates ATPase activity in a dose-dependent manner, which is required for the proper function of P-gp. In contrast, ZD6474 does not inhibit the expression level of P-gp. Our results suggest that ZD6474 is capable of reversing MDR in cancer cells by directly inhibiting the function of P-gp, a finding that may have clinical implications for ZD6474.

EDDS and EDTA-enhanced phytoextraction of metals from artificially contaminated soil and residual effects of chelant compounds

The potential of 18 different plants to be used in the chemically enhanced phytoextraction of Cu, Pb, Zn and Cd was assessed using pot experiments. Chrysanthemum coronarium L. was the species most sensitive to the application of EDTA, and had the highest enhancement of Cu and Pb concentrations in its shoots. Compared with EDTA, EDDS was more effective in enhancing the concentration of Cu in the shoots of Chrysanthemum coronarium L. and Zea mays L. grown on multi-metal contaminated soils. The EDTA-treated soil still had a significant ability to enhance the concentrations of Cu and Pb in the shoots of Zea mays L. six months after the chelant treatment. However, the EDDS-treated soil did not have any effect in enhancing the concentrations of metals in the shoots of Zea mays L. in the second crop test. The results may indicate that EDDS biodegrades more rapidly than EDTA in soil and is better in limiting potential metal leaching.

Transhemispheric functional reorganization of the motor cortex induced by the peripheral contralateral nerve transfer to the injured arm

Peripheral nerve injury in a limb usually causes functional reorganization of the contralateral motor cortex. However, a dynamic process of the novel transhemispheric functional reorganization in the motor cortex was found in adult rats after transferring the seventh cervical nerve root from the contralateral healthy side to the injured limb. Initially the ipsilateral motor cortex activated the injured forepaw for 5 months after the operation. Then, both hemispheres of the cortex activated the injured forepaw, and finally the contralateral cortex exclusively controlled the injured forepaw. It is concluded an extensive functional shift occurred between two hemispheres based on neural plasticity in the CNS. The experimental results of the later lesions of the ipsilateral cortex suggest that maintaining transhemispheric functional reorganization does not depend on the corpus callosum, but depends on mechanisms involving central axonal sprouting. Possible mechanisms underlying the alternative changes in cortical functions were discussed in rats and in patients having similar operations.

[Plasma Lp (a) levels and correlation of Lp (a) with fibrinolysis activation in chronic renal failure]

Plasma Lp (a) concentration and activation of tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor-1(PAI-1) were determined in 50 patients with chronic renal failure (CRF) and in 50 healthy subjects. The results demonstrated that plasma concentration of Lp(a) was significantly higher and plasma t-PA activation was significantly lower in CRF patients than in healthy subjects. With multivariate analyses, plasma Lp(a) concentration was positively correlated with the total amount of 24 h uric protein, plasma BUN and uric protein concentration. Moreover, a negative significant correlation between plasma Lp(a) levels and t-PA activation was observed. Plasma Lp(a) levels did not show a correlation to PAI-1 activation. It is indicated that renal function may contribute to moderate plasma Lp(a) concentration and elevated Lp(a) levels may be related with fibrinolytic impairment.

Effects of voluntary attention on structured afterimages

The effect of voluntary attention on afterimage fragmentation was explored in two experiments. The afterimage, in the form of a 30 degrees-tilted star of David, was generated after prolonged steady fixation in the first experiment, and with a brief and intense flash in the second experiment. Subjects were instructed to select various target shapes in the afterimage for attention and, at the same time, observe what was visible or invisible. Verbal reports and manual responses to afterimage changes were analyzed. Attended shapes were found to disappear from awareness Faster than unattended ones (experiment 1), and complementary shapes were found to predominate visual awareness when one of the pair was selected for attention (experiment 2). Voluntary attention was also found to affect closure (filling-in of enclosed regions) and smoothing of line figures in afterimages.

Subdural Blood Patch for the Treatment of Persistent CSF Leak After Permanent Intrathecal Catheter Implantation: A Report of Two Cases

A CSF leak that persists despite conservative therapy may significantly increase the morbidity associated with implantable intrathecal drug delivery systems. This report presents 2 cases where the application of a subdural blood patch led to the satisfactory resolution of a persistent CSF leak after previous epidural blood patches had failed.

[Luminescence dependence upon concentration and temperature in YPO4:Pr3+]

Under selective excitation 3P0 state of Pr3+ ion in YPO4, the emission spectra and fluorescence decay curves are measured at different concentrations and temperatures. The origin of the spectral line located at 613.2 nm has been discussed and assigned to be the 1D2 (gamma 3)-->3H4 (gamma 5) transition. The different concentration dependence of emission intensities of levels 3P0 and 1D2 has been studied. Using static model, the fluorescence decay curve of 1D2 level is fitted, and the result shows that the cross-relaxation caused by the interaction of dipole-quadrupole between adjacent Pr3+ ions results in the concentration quenching.

Uncommon areas of electrical stimulation for pain relief

Uncommon stimulation refers to the use of peripheral nerve and spinal cord stimulation for nontraditional applications. There has been much interest recently with subcutaneous suboccipital stimulation for occipital neuralgia, sacral stimulation for pelvic pain, trigeminal stimulation for trigeminal neuralgia, and spinal cord stimulation for angina and peripheral ischemia. The indications and techniques used for accomplishing each method are discussed.

Evidence-based review of the literature on intrathecal delivery of pain medication

Evidence-based medicine depends on the existence of controlled clinical trials that establish the safety and efficacy of specific therapeutic techniques. Many interventions in clinical practice have achieved widespread acceptance despite little evidence to support them in the scientific literature; the critical appraisal of these interventions based on accumulating experience is a goal of medicine. To clarify the current state of knowledge concerning the use of various drugs for intraspinal infusion in pain management, an expert panel conducted a thorough review of the published literature. The exhaustive review included 5 different groups of compounds, with morphine and bupivacaine yielding the most citations in the literature. The need for additional large published controlled studies was highlighted by this review, especially for promising agents that have been shown to be safe and efficacious in recent clinical studies.

Clinical guidelines for intraspinal infusion: report of an expert panel. PolyAnalgesic Consensus Conference 2000

Consensus guidelines developed by an expert panel are helpful to clinicians when there is variation in practice and lack of a firm evidence base for an intervention, such as intraspinal therapy for pain. An internet-based survey of practitioners revealed remarkable variation in practice patterns surrounding intraspinal therapy. This prompted an interdisciplinary panel with extensive clinical experience in intraspinal infusion therapy to evaluate the results of the survey, the systematic reviews of the literature pertaining to this approach, and their own clinical experience with long-term spinal infusions. The panel proposed a scheme for the selection of drugs and doses for intraspinal therapy, and suggested guidelines for administration that would increase the likelihood of a successful outcome. These expert panel guidelines were designed to provide an initial structure for clinical decision making that is based on the best available evidence and the perspectives of experienced clinicians.

Selective peripheral fading: evidence for inhibitory sensory effect of attention

A circular array of six discs, three green and three orange in alternate positions, was presented against a uniform grey background. Sixteen observers maintained steady fixation at the centre of the array, and were instructed to direct their attention to three discs of one colour and to ignore the three discs of the other colour. In about 10 s (mean = 11.35 s), some discs started to fade away from awareness. Of those starting to fade, most (mean = 81.3%) were those selected for attention. The faded discs remained out of awareness for up to a few seconds (mean = 1.55 s) during which other discs were clearly visible. The fading increased with eccentricity, a defining characteristic of Troxler fading. However, the selectivity of the fading strongly suggests that voluntary attention can have an inhibitory effect on early sensory processing. Were the fading entirely due to local sensory adaptation, the unattended stimuli would have to be equally adapted and yet somehow remain visible for seconds, which is not plausible.

Mechanisms of speed-accuracy tradeoff: evidence from covert motor processes

Speed-accuracy tradeoff (SAT) refers to the inverse relation between speed and accuracy found in many tasks. The present study employed reaction times (RTs) and movement-related brain potentials arising during the RT interval (lateralized readiness potentials; LRPs) to examine the mechanisms by which people control their position along an SAT continuum. Many models of SAT postulate that changes in position across conditions (macro-tradeoffs) and trial-by-trial variations within conditions (micro-tradeoffs) are mediated, at least in part, by the same mechanisms. These include: (1) all models that postulate mixtures of guesses and accurate responses and (2) some models postulating decision criterions applied to accumulating evidence or response tendencies. Such models would seem to be rejected for conditions under which macro- and micro-tradeoffs can be shown to involve no stages of RT in common. Under the present conditions, the two types of SAT produced additive effects on RT, with the macro-tradeoff involving only that portion of the RT interval occurring after LRP onset and the micro-tradeoff involving only that portion before LRP onset. These findings imply that the two types of SAT arose during different serial stages of RT and that the macro-tradeoff involved only stages occurring after differential preparation of the two hands had begun.