What measure of temperature is the best predictor of mortality?

Hot and cold temperatures significantly increase mortality rates around the world, but which measure of temperature is the best predictor of mortality is not known. We used mortality data from 107 US cities for the years 1987-2000 and examined the association between temperature and mortality using Poisson regression and modelled a non-linear temperature effect and a non-linear lag structure. We examined mean, minimum and maximum temperature with and without humidity, and apparent temperature and the Humidex. The best measure was defined as that with the minimum cross-validated residual. We found large differences in the best temperature measure between age groups, seasons and cities, and there was no one temperature measure that was superior to the others. The strong correlation between different measures of temperature means that, on average, they have the same predictive ability. The best temperature measure for new studies can be chosen based on practical concerns, such as choosing the measure with the least amount of missing data.

Noise and signal properties in PSF-based fully 3D PET image reconstruction: an experimental evaluation

The addition of accurate system modeling in PET image reconstruction results in images with distinct noise texture and characteristics. In particular, the incorporation of point spread functions (PSF) into the system model has been shown to visually reduce image noise, but the noise properties have not been thoroughly studied. This work offers a systematic evaluation of noise and signal properties in different combinations of reconstruction methods and parameters. We evaluate two fully 3D PET reconstruction algorithms: (1) OSEM with exact scanner line of response modeled (OSEM+LOR), (2) OSEM with line of response and a measured point spread function incorporated (OSEM+LOR+PSF), in combination with the effects of four post-reconstruction filtering parameters and 1-10 iterations, representing a range of clinically acceptable settings. We used a modified NEMA image quality (IQ) phantom, which was filled with 68Ge and consisted of six hot spheres of different sizes with a target/background ratio of 4:1. The phantom was scanned 50 times in 3D mode on a clinical system to provide independent noise realizations. Data were reconstructed with OSEM+LOR and OSEM+LOR+PSF using different reconstruction parameters, and our implementations of the algorithms match the vendor's product algorithms. With access to multiple realizations, background noise characteristics were quantified with four metrics. Image roughness and the standard deviation image measured the pixel-to-pixel variation; background variability and ensemble noise quantified the region-to-region variation. Image roughness is the image noise perceived when viewing an individual image. At matched iterations, the addition of PSF leads to images with less noise defined as image roughness (reduced by 35% for unfiltered data) and as the standard deviation image, while it has no effect on background variability or ensemble noise. In terms of signal to noise performance, PSF-based reconstruction has a 7% improvement in contrast recovery at matched ensemble noise levels and 20% improvement of quantitation SNR in unfiltered data. In addition, the relations between different metrics are studied. A linear correlation is observed between background variability and ensemble noise for all different combinations of reconstruction methods and parameters, suggesting that background variability is a reasonable surrogate for ensemble noise when multiple realizations of scans are not available.

Difference in mosquito species (Diptera: Culicidae) and the transmission of Ross River virus between coastline and inland areas in Brisbane, Australia

This study examined the distribution of major mosquito species and their roles in the transmission of Ross River virus (RRV) infection for coastline and inland areas in Brisbane, Australia (27 degrees 28' S, 153 degrees 2' E). We obtained data on the monthly counts of RRV cases in Brisbane between November 1998 and December 2001 by statistical local areas from the Queensland Department of Health and the monthly mosquito abundance from the Brisbane City Council. Correlation analysis was used to assess the pairwise relationships between mosquito density and the incidence of RRV disease. This study showed that the mosquito abundance of Aedes vigilax (Skuse), Culex annulirostris (Skuse), and Aedes vittiger (Skuse) were significantly associated with the monthly incidence of RRV in the coastline area, whereas Aedes vigilax, Culex annulirostris, and Aedes notoscriptus (Skuse) were significantly associated with the monthly incidence of RRV in the inland area. The results of the classification and regression tree (CART) analysis show that both occurrence and incidence of RRV were influenced by interactions between species in both coastal and inland regions. We found that there was an 89% chance for an occurrence of RRV if the abundance of Ae. vigilax was between 64 and 90 in the coastline region. There was an 80% chance for an occurrence of RRV if the density of Cx. annulirostris was between 53 and 74 in the inland area. The results of this study may have applications as a decision support tool in planning disease control of RRV and other mosquito-borne diseases.

The microfilament cytoskeleton plays a vital role in salt and osmotic stress tolerance in Arabidopsis

Although recent studies have suggested that the microfilament (MF) cytoskeleton of plant cells participates in the response to salt stress, it remains unclear as to whether the MF cytoskeleton actually plays an active role in a plant's ability to withstand salt stress. In the present study, we report for the first time the role of MFs in salt tolerance of Arabidopsis thaliana. Our experiments revealed that Arabidopsis seedlings treated with 150 mm NaCl maintained MF assembly and bundle formation, whereas treatment with 250 mm NaCl initially induced MF assembly but subsequently caused MF disassembly. A corresponding change in the fluorescence intensity of MFs was also observed; that is, a sustained rise in fluorescence intensity in seedlings exposed to 150 mm NaCl and an initial rise and subsequent fall in seedlings exposed to 250 mm NaCl. These results suggest that MF assembly and bundles are induced early after salt stress treatment, while MF polymerization disappears after high salt stress. Facilitation of MF assembly with phalloidin rescued wild-type seedlings from death, whereas blocking MFs assembly with latrunculin A and cytochalasin D resulted in few survivors under salt stress. Pre-treatment of seedlings with phalloidin also clearly increased plant ability to withstand salt stress. MF assembly increased survival of Arabidopsis salt-sensitive sos2 mutants under salt stress and rescued defective sos2 mutants. Polymerization of MFs and its role in promoting survival was also found in plants exposed to osmotic stress. These findings suggest that the MF cytoskeleton participates and plays a vital role in responses to salt and osmotic stress in Arabidopsis.

153. COMBINATION METHOTREXATE AND EPIDERMAL GROWTH FACTOR RECEPTOR INHIBITION AS A NOVEL MEDICATION-BASED CURE OF ECTOPIC PREGNANCIES

Ectopic pregnancies are serious gynaecological emergencies that can cause fatal haemorrhage. Most are treated surgically. Given the placenta is heavily reliant on Epidermal Growth Factor Receptor (EGFR) signaling, we set out to develop a medication-based treatment of ectopics using combination gefitinib (EGFR inhibitor) and methotrexate (folate antagonist). Both drugs are well tolerated and available in tablet form. We used in vitro and in vivo approaches to test the ability of gefitinib and methotrexate to regress placental tissue, and to explore molecular mechanisms. In vitro assays included immunohistochemistry (EGFR staining) western blot (EGFR phosphorylation), cell viability assays (Cell-Titre Blue, LDH cytotoxicity assay, xCELLigence system), apoptosis assays (PCR, FACS of M30 antibody) and The Bioplex Platform (phosphorylation of the EGFR pathway). JEG-3 xenografts were used to assess regression of placental tissue in vivo, where serum hCG was also measured (ELISA). EGFR was highly expressed in placentae from ectopic pregnancies. Combination treatment was supra-additive in inducing cell death of placental tissue in vitro, with >70% cell death by 48 hours (Syncytialised BeWos, JEG-3 and 1st trimester trophoblast). This supra-additive effect was demonstrated in both end point assays (cell viability) and regular monitoring using The xCELLigence system. Gefitinib potently blocks EGFR phosphorylation in placental tissues in vitro (Western blot). Both drugs may be converging to inhibit Akt phosphorylation (Bioplex analysis). Combination treatment increases apoptosis (FACS of M30 antibody). In vivo, Gefitinib or MTX as single agents induced significant decrease in xenograft tumour volume in a dose dependent manner (n ≤ 5 mice per treatment). However, combining these drugs was supra-additive in decreasing xenograph tumour volume and weight. Serum hCG in mice was lowest with combination treatment. Combination gefitinib and methotrexate potently regresses placental tissue. It may be a novel therapeutic approach to cure ectopic pregnancies, potentially replacing surgery with tablets.

419. Rational design of bifunctional siRNAs that silence genes and recruit the innate immune system to treat ectopic pregnancies

RNA interference (RNAi) is a new therapeutic approach, silencing genes to disrupt diseases. However, short interfering siRNAs (molecule used in RNAi) can have off-target effects, activating the immune system through RNA sensing toll-like receptors (TLR) 3, 7 and 8. We have previously proposed that in some diseases (cancers, ectopic pregnancies) it may be useful to enhance the immune response. A novel class of immunostimulatory siRNAs could be developed, silencing genes important to disease and recruiting the immune system to further aid disease clearance. We set out to develop a rational design strategy that enhances immunostimulatory properties to any siRNA sequence but maintains effective gene silencing. We screened a set of siRNAs targeting lamin. All were of the same sequence, except for different immunostimulatory motifs on the 3′ end of the sense strand. We also investigated a different design where we added a small micro-RNA like poly-uridine bulge (potentially immunostimulatory) on the sense strand. We used human peripheral blood mononuclear cells (PBMCs) to test for immunostimulation, and HEK 293-T-cells to test for lamin gene knockdown.Of all strategies tested, the poly-uridine bulge was best. It silenced the lamin gene as effectively as control, but caused a 2–3 fold increase of IFN-α and TNF-α. We verified this approach by adding the poly-uridine bulge onto an siRNA of low immunostimulatory potential targeting GFP. The bulge markedly enhanced immunostimulation in a dose response manner, and did not compromise gene knockdown. The addition of a poly-uridine bulge to siRNAs can increase immunostimulation without affecting gene silencing efficacy. Immunostimulatory siRNAs might be particularly efficacious to treat ectopic pregnancies where there are abundant immune cells, and functional TLR 7/8 in the trophoblast (unpublished observations). We now plan to test this immunostimulatory siRNA approach in an in vivo ectopic pregnancy model using JEG-3 cells xenographted in NOD-SCID mice.

Application of particle swarm system as a novel parameter optimization technique on spatiotemporal retina model

Center-surround spatiotemporal (ST) filter is a powerful tool to simulate the spatial and temporal properties of retina ganglion cells and encode visual information with electric spikes. This paper introduces the application of particle swarm optimization (PSO) algorithm to tune the parameters in the retina model consisting of a ST filter module and a back-propagation (BP) neural network module. Images are converted into electric spikes by the ST filters whose outputs are then fed into the BP neural network to reconstruct the output images. The parameters of the ST filters determine the electric spike sequences as well as the output image from the BP network. In order to get the expected output images, we employ PSO to iteratively tune the parameters. Euclidean distance between output and input image is used as scalar criteria to optimize the ST filter. The tuning process stops until the similarity between output and input images no longer improves. The results show that 62.3% of the images trained by PSO have better output image quality and less iteration time compared with those trained by the current evolution strategy (ES).

Ozone modifies associations between temperature and cardiovascular mortality: analysis of the NMMAPS data

OBJECTIVES

Both ambient ozone and temperature are associated with human health. However, few data are available on whether ozone modifies temperature effects. This study aims to explore whether ozone modified associations between maximum temperature and cardiovascular mortality in the USA.

METHODS

The authors obtained data from the US National Morbidity, Mortality, and Air Pollution Study (NMMAPS) website. They used two time-series Poisson regression models (a response surface model and a stratification model) to examine whether ozone modified associations between maximum temperature and cardiovascular mortality (CVM) in 95 large US communities during 1987-2000 in summer (June to September). Bayesian meta-analysis was used to pool estimates in each community.

RESULTS

The response surface model was used to examine the joint effects of temperature and ozone on CVM in summer. Results indicate that ozone positively modified the temperature-CVM associations across the different regions. The stratification model quantified the temperature-CVM associations across different levels of ozone. Results show that in general the higher the ozone concentration, the stronger the temperature-CVM associations across the communities. A 10 degrees C increase in temperature on the same day was associated with an increase in CVM by 1.17% and 8.31% for the lowest and highest level of ozone concentrations in all communities, respectively.

CONCLUSION

Ozone modified temperature effects in different regions in the USA. It is important to evaluate the modifying role of ozone when estimating temperature-related health impacts and to further investigate the reasons behind the regional variability and mechanism for the interaction between temperature and ozone.

Relevance of combinatorial profiles of intermediate filaments and transcription factors for glioma histogenesis

In order to define specific markers for histogenesis of three well-characterized subgroups of human gliomas (pilocytic astrocytomas, glioblastoma multiforme and oligodendrogliomas), we studied the expression of relevant markers that characterize gliomagenesis, by immunohistochemistry and in situ hybridization. They include the intermediate filament proteins glial fibrillary acidic protein (GFAP), vimentin and nestin, the transcription factors Olig2, Nkx2.2 and Sox10, and the proteolipid protein transcripts plp/dm20. We show that the three major categories of human gliomas express a combinatorial profile of markers that gives new insights to their histogenesis and may help diagnosis. Pilocytic astrocytomas strongly express GFAP, vimentin, Olig2, Nkx2.2 and Sox10 but not nestin. In contrast, glioblastomas strongly express GFAP, vimentin and nestin but these tumours are heterogeneous regarding the expression of the transcription factors studied. Finally, in oligodendrogliomas, intermediate filament proteins are generally not observed whereas Olig2 was found in almost all tumour cells nuclei while only a subpopulation of tumour cells expressed Nkx2.2 and Sox10.

Highly specific and sensitive rise in Days 14–17 pro-αC inhibin with clinical pregnancy after frozen embryo transfer with ovulatory cycles

BACKGROUND

Pro-alphaC inhibins are luteal derived analytes peaking in the maternal serum as early as Day 16 after conception. We set out to verify a previous post hoc analysis which suggested that pro-alphaC levels measured this early are extremely sensitive in predicting clinical pregnancy success after unstimulated IVF with ovulatory cycles.

METHODS

Prospective observational study of 246 women undergoing frozen embryo transfer with ovulatory cycles. Serum pro-alphaC and beta-HCG levels at 14-17 days after conception were measured by enzyme-linked immunosorbent assay and grouped according to whether a clinical pregnancy occurred (demonstrable cardiac activity at > or =6 weeks' gestation).

RESULTS

Of 34 (13.8%) women who achieved a clinical pregnancy, median (25th-75th centile) Days 14-17 pro-alphaC levels were 995 pg/ml (758-1463), 6- to 7-fold higher than levels observed in the remainder who did not fall pregnant (112.8 pg/ml (104-121); P < 0.0001). At a fixed 95% specificity, pro-alphaC was 100% sensitive in predicting clinical pregnancy. The best specificities achieved at 100% sensitivity were; 94.8% for pro-alphaC, 96.7% for beta-HCG and 98.1% when both analytes were combined.

CONCLUSIONS

Clinical pregnancy is always associated with a release of luteal derived pro-alphaC 14-17 days after conception. Pro-alphaC may play a possible biological role and be a useful clinical biomarker of luteal health.

The activation of TC10, a Rho small GTPase, contributes to v-Rel-mediated transformation

v-Rel is the oncogenic member of the Rel/NF-kappaB family of transcription factors and transforms hematopoietic cells and fibroblasts. Differential display was employed to identify target genes that exhibit altered expression in v-Rel transformed cells. One of the cDNAs identified encodes the chicken ortholog of TC10, a member of the Rho small GTPase family. The expression of TC10 was increased in v-Rel-transformed chicken embryonic fibroblasts (CEFs) 3 to 6-fold relative to control cells at both the RNA and protein levels. An elevated level of active, GTP-bound TC10 was also detected in v-Rel-transformed cells relative to control cells. Expression of a dominant-negative TC10 mutant (TC10T32N) decreased the colony formation potential of v-Rel-transformed cells. Furthermore, overexpression of wild-type TC10 or a gain-of-function mutant (TC10Q76L) greatly enhanced the ability of v-Rel transformed CEFs to form colonies in soft agar. In addition to enhance the transformation potential of v-Rel, the overexpression of wild-type TC10 or the gain-of-function mutant alone enhanced the saturation density of CEFs and was sufficient for their anchorage-independent growth in vitro. These results indicate that elevated TC10 activity contributes to v-Rel-mediated transformation of CEFs and demonstrate for the first time that a Rho factor alone is capable of inducing the in vitro transformation of primary cells.