An Ultrahigh Resolution SPECT System for I-125 Mouse Brain Imaging Studies

This paper presents some initial experimental results obtained with a dual-head prototype single photon emission microscope system (SPEM) that is dedicated to mouse brain studies using I-125 labeled radiotracers. In particular, this system will be used for in vivo tacking of radiolabeled T cells in mouse brain. This system is based on the use of the intensified electron multiplying charge-coupled device (I-EMCCD) camera that offers the combination of an excellent intrinsic spatial resolution, a good signal-to-noise ratio, a large active area and a reasonable detection efficiency over an energy range between 27-140keV. In this study, the dual-head SPEM system was evaluated using both resolution phantoms and a mouse with locally injected T cells labelled with I-125. It was demonstrated that for a relatively concentrated source object, the current dual-head SPEM system is capable of visualizing the tiny amount of radioactivity (~12 nCi) carried by a very small number (<1000) of T cells. The current SPEM system design allows four or six camera heads to be installed in a stationary system configuration that offers a doubled or tripled sensitivity at a spatial resolution similar to that obtained with the dualhead system. This development would provide a powerful tool for in vivo and non-invasive tracking of radiolabeled T cells in mouse brain and potentially for other rodent brain imaging studies.

Microglial activation and brain injury after intracerebral hemorrhage

Microglial activation and thrombin formation contribute to brain injury after intracerebral hemorrhage (ICH). Tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 beta (IL-1beta) are 2 major proinflammatory cytokines. In this study, we investigated whether thrombin stimulates TNF-alpha and IL-1beta secretion in vitro, and whether microglial inhibition reduces ICH-induced brain injury in vivo. There were 2 parts to this study. In the first part, cultured rat microglial cells were treated with vehicle, thrombin (5 and 10U/mL), or thrombin plus tuftsin (0.05 microg/mL), an inhibitor of microglia activation. Levels of TNF-alpha and IL-1beta in culture medium were measured by ELISA at 4, 8, and 24 h after thrombin treatment. In the second part of the study, rats received an intracerebral infusion of 100 microL autologous whole blood with or without 25 microg of tuftsin 1-3 fragment. Rats were killed at day 1 or day 3 for immunohistochemistry and brain water content measurement. We found that thrombin receptors were expressed in cultured microglia cells, and TNF-alpha and IL-1beta levels in the culture medium were increased after thrombin treatment. Tuftsin reduced thrombin-induced upregulation of TNF-alpha and IL-1beta. In vivo, microglia were activated after ICH, and intracerebral injection of tuftsin reduced brain edema in the ipsilateral basal ganglia (81.1 +/- 0.7% vs. 82.7 +/- 1.3% in vehicle-treated group; p < 0.05) after ICH. These results suggest a critical role of microglia activation in ICH-related brain injury.

Use of surrogate modelling for multiobjective optimisation of urban wastewater systems

Simulation models are now available to represent the sewer network, wastewater treatment plant and receiving water as an integrated system. These models can be combined with optimisation methods to improve overall system performance through optimal control. Evolutionary algorithms (EAs) have been proven to be a powerful method in developing optimal control strategies; however, the intensive computational requirement of these methods imposes a limit on their application. This paper explores the potential of surrogate modelling in multiobjective optimisation of urban wastewater systems with a limited number of model simulations. A surrogate based method, ParEGO, is combined with an integrated urban wastewater model to solve real time control problems. This method is compared with the popular NSGA II, by using performance indicators: the hypervolume indicator, additive binary epsilon-indicator and attainment surface. Comparative results show that ParEGO is an efficient and effective method in deriving optimal control strategies for multiple objective control problems with a small number of simulations. It is suggested that ParEGO can greatly improve computational efficiency in the multiobjective optimisation process, particularly for complex urban wastewater systems.

Investigation of the Intrinsic Spatial Resolution of an Intensified EMCCD Scintillation Camera

In this paper, we present an experimental and Monte Carlo investigation of the intrinsic spatial resolution that can be achieved with the intensified electron-multiplying charge-coupled device (I-EMCCD) gamma camera [1]-[4]. This detector has a very low readout noise, an ultra-high spatial resolution and a large active area of ~ 80 mm diameter, which is well-suited for small animal imaging applications. The intrinsic detector resolutions achieved with different scintillators and under different experimental conditions were compared. In this study, the simple centroiding method was compared with two model-fitting approaches for finding the locations of gamma ray interactions. The results from Monte Carlo simulation have demonstrated that with an appropriate detector configuration, it is possible to achieve an intrinsic resolution of ~ 30 µm FWHM for detecting 27-35 keV gamma rays. The I-EMCCD scintillation camera offers a promising candidate for future ultra-high resolution SPECT imaging applications.

Expression of tPA, LH receptor and inhibin alpha, beta(A) subunits during follicular atresia in rats

By using DNA 3'-end labeling, immunocytochemistry and mRNA in situ hybridization detection techniques, the expression of inhibin subunits and LH receptor in the granulosa cells and tissue-type plasminogen activator (tPA) in the oocytes has been studied in relation to follicular development and atresia. The results demonstrated that: (i) tPA activity in the oocytes of normal developing follicles is undetectable, and increases significantly in the follicle undergoing atresia; (ii) the production of inhibin subunits in granulosa cells is negatively correlated with the expression of oocyte tPA activity, indicating that they may be an important regulator of oocyte tPA production and follicular development; (iii) in atretic follicles, granulosa cells do not express LH receptor and inhibin subunits. It is therefore suggested that tPA may play a role in oocyte self-destruction and clearance in some of atretic follicles, and inhibin of granulosa-origin might be an inhibitory factor for the translation of tPA in the oocyte.

Application of radiation hybrid in gene mapping

Radiation hybrid (RH) mapping technique was exploited to determine chromosome locations of 26 human novel full length cDNAs recently cloned. All these cDNA clones were isolated from human cord blood CD (+) (34) cells and may be related to regulation of hematopoiesis. 23 genes were successfully mapped to chromosomal positions, while RH analyses were not possible in the remaining 3 cases. RH technique is indeed a powerful tool for mapping novel cDNA sequences due to its rapidity, precision, convenience and reproducibility.

Overlapping BXSB congenic intervals, in combination with microarray gene expression, reveal novel lupus candidate genes

The BXSB mouse strain is an important model of glomerulonephritis observed in systemic lupus erythematosus (SLE). Linkage studies have successfully identified disease-susceptibility intervals; however, extracting the identity of the susceptibility gene(s) in such regions is the crucial next step. Congenic mouse strains present a defined genetic resource that is highly amenable to microarray analysis. We have performed microarray analysis using a series of chromosome 1 BXSB congenic mice with partially overlapping disease-susceptibility intervals. Simultaneous comparison of the four congenic lines allowed the identification of expression differences associated with both the initiation and progression of disease. Thus, we have identified a number of novel SLE disease gene candidates and have confirmed the identity of Ifi202 as a disease candidate in the BXSB strain. Sequencing of the promoter regions of Gas5 has revealed polymorphisms in the BXSB strain, which may account for the differential expression profile. Furthermore, the combination of the microarray results with the different phenotypes of these mice has allowed the identification of a number of expression differences that do not necessarily map to the congenic interval, but may be implicated in disease pathways.

DNA sequence and comparative analysis of chimpanzee chromosome 22

Human-chimpanzee comparative genome research is essential for narrowing down genetic changes involved in the acquisition of unique human features, such as highly developed cognitive functions, bipedalism or the use of complex language. Here, we report the high-quality DNA sequence of 33.3 megabases of chimpanzee chromosome 22. By comparing the whole sequence with the human counterpart, chromosome 21, we found that 1.44% of the chromosome consists of single-base substitutions in addition to nearly 68,000 insertions or deletions. These differences are sufficient to generate changes in most of the proteins. Indeed, 83% of the 231 coding sequences, including functionally important genes, show differences at the amino acid sequence level. Furthermore, we demonstrate different expansion of particular subfamilies of retrotransposons between the lineages, suggesting different impacts of retrotranspositions on human and chimpanzee evolution. The genomic changes after speciation and their biological consequences seem more complex than originally hypothesized.

Mechanisms of Mineral Scale Inhibition

Summary

An extensive study of adsorption and desorption isotherms of four phosphonates on barite or calcite are tested for a wide range of solution conditions (0 to 1 M NaCl, 0 to 0.1 M Ca, 0 to 0.33 M sulfate, and 4.6 to 6.4 pH). From these adsorption/desorption observations, it is proposed that the primary driving force for adsorption is related to simple hydrophobic repulsion from solution of a macroneutral molecule and not, as is generally presumed, some specific inhibitor-surface interaction. From the nucleation study, it is observed that the inhibitor needed to completely inhibit barite formation is approximately equal to 16% surface coverage. An equation to predict minimum inhibitor need is proposed based on this model and is compared with field observations. The range of predicted inhibitor concentrations is quite similar to what is observed in the field as a minimum effective dose even though it was derived by a completely independent calculation method.

Introduction

Scale formation in gas and oil wells is a common and persistent problem during production, treatment, transportation, and disposal of coproduced salt water; inhibition of this scale formation is a priority. The most common mineral scale materials and the focus of this research are calcite (CaCO3), barite (BaSO4), gypsum and related calcium sulfates (CaSO4 × xH2O, x=2, 1/2, 0), celestite (SrSO4), siderite (FeCO3), halite (NaCl), and zinc and iron sulfides (Zn/FeS). In addition, related hydrocarbon-based deposits include gas hydrates, waxes, alphaltenes, naphthenates, and sulfur. The primary focus of this research report is the formation and control of the sparingly soluble mineral scales. Most research on scale formation has focused on measuring and predicting the rate and amount of scale formation under different conditions of T, p, and brine composition. The Rice U. Brine Chemistry Consortium has spent several years examining nucleation and precipitation rates and continues to do so, but the focus of this research has been on the mechanism(s) of mineral scale inhibition. In fact, scale formation and inhibition are intimately related to each other (e.g., a rule of thumb is that scale inhibitors are typically insoluble salts of one of the mineral lattice ions).

Rates of nucleation and crystal growth in the absence of specific inhibitors are normally related to the mineral saturation ratio [e.g., SR(calcite)={Ca2+}{CO32–}/Kcalcitesp] or the logarithm of the saturation ratio, called the saturation index (SI). Thermodynamics provides several very specific guidelines, or suggestive equations, for nucleation and crystal growth, and these equations have been known for more than a century. There is no equivalent set of fundamental principles that can be used to predict scale inhibition. There are some more-or-less intuitive notions that inhibitors must interact with the forming nuclei or the growing crystal in some manner.1–3 The nature, amount, or type of these inhibitor interactions with the crystal/nucleus surface can not now be predicted from any set of fundamental principles of thermodynamics or kinetics. It is often reported that a specific inhibitor is better for calcite than barite and vice versa; clearly, there will be empirical differences, as reported by the present authors and many others. Yet under identical solution conditions and a corresponding driving force, it is normally reported that an inhibitor of one will inhibit the other mineral scale as long as there is sufficient divalent metal ions present for complexation. The focus of this paper is the common mechanistic origins of inhibition of both calcite and barite, but the differences, although often only at the percentage levels, need to be better understood. Consequently, there is little agreement on how to model inhibition at the molecular or process level. This dearth of guiding theoretical laws is common to all forms of scale formation, not just in oilfield-produced fluids.

Several questions need to be answered for oilfield scale control specifically. First is, simply, why do inhibitors prevent nucleation and crystal growth, especially at such low concentrations as 1 mg/L and lower? A reliable molecular correlation to account for variations in needed inhibitor concentration with T, p, and brine composition would be of great value but does not presently exist. Second, why do inhibitor squeezes, as typically performed in the industry, work so well? The fundamental problem is that the mechanism(s) responsible for inhibitor chemical retention in the formation and subsequent slow release is not, according to any present theory, connected to the inhibition of nucleation and scale formation in the flowing brine. For example, why is the precipitation/ adsorption of some calcium phosphonate (Ca-Phn) in the reservoir mechanistically related to the inhibition of CaCO3 or BaSO4? In some ways, this is an extension of the first question of why or how inhibitors work. If it were known how and why squeezes work, it might be understood why they often fail, even though as much as one-third of the Ca-Phn remains in the reservoir. Any added understanding of the mechanism of inhibitor/ squeeze action would be useable to guide future inhibitor selection, synthesis, and testing. Finally, molecular understanding of scale inhibition should lead to the prediction of theoretical inhibitor- performance limits as guidelines against which to measure field performance.

Models of nucleation kinetics are generally based around the classical theory of nucleation and are characterized by the logarithm of the induction time being proportional to the nuclei surface tension divided by the SI squared to various exponents. For example, we have found that the measured induction time for barite, in the absence of inhibitor (t0ind) and more than approximately 5 orders of magnitude, can be described by the following function.

Gene expression in CD34(+) cells from normal bone marrow and leukemic origins

INTRODUCTION

To address the molecular regulation of hematopoiesis and the complex mechanism in leukemogenesis, we established the first catalogs of genes expressed in normal bone marrow and leukemia CD34(+) cells.

MATERIALS AND METHODS

CD34(+) cell cDNA libraries were constructed using mRNA from adult bone marrow and from a case of acute myeloid leukemia-M5 transformed from myelodysplastic syndrome (MDS-AML). Expressed sequence tags (ESTs) and full-length cDNAs were generated by sequencing and were annotated using bioinformatic tools.

RESULTS

From a total of 4142 ESTs obtained from normal bone marrow, 3424 meaningful tags were integrated into 1630 clusters, representing 622 known genes, 522 dbEST entries and 486 novel sequences. Out of 5382 ESTs from MDS-AML, 1985 clusters were produced based on the analysis of 4321 useful ESTs, including 711 known genes, 657 known ESTs and 617 novel sequences. Among 251 transcripts found in both bone marrow and MDS-AML EST datasets and those present in only one dataset, 58 showed statistically significant differences in EST copy numbers between the two tissues (P<0.05). Twenty putative full-length cDNAs for novel genes were also cloned from the MDS-AML library.

CONCLUSION

The distinct gene expression patterns in MDS-AML-CD34(+) cells as compared to normal control cells may contribute to the development and/or maintenance of the malignant phenotypes of leukemia cells.

Insight into hepatocellular carcinogenesis at transcriptome level by comparing gene expression profiles of hepatocellular carcinoma with those of corresponding noncancerous liver

Human hepatocellular carcinoma (HCC) is one of the most common cancers worldwide. In this work, we report on a comprehensive characterization of gene expression profiles of hepatitis B virus-positive HCC through the generation of a large set of 5'-read expressed sequence tag (EST) clusters (11,065 in total) from HCC and noncancerous liver samples, which then were applied to a cDNA microarray system containing 12,393 genes/ESTs and to comparison with a public database. The commercial cDNA microarray, which contains 1,176 known genes related to oncogenesis, was used also for profiling gene expression. Integrated data from the above approaches identified 2,253 genes/ESTs as candidates with differential expression. A number of genes related to oncogenesis and hepatic function/differentiation were selected for further semiquantitative reverse transcriptase-PCR analysis in 29 paired HCC/noncancerous liver samples. Many genes involved in cell cycle regulation such as cyclins, cyclin-dependent kinases, and cell cycle negative regulators were deregulated in most patients with HCC. Aberrant expression of the Wnt-beta-catenin pathway and enzymes for DNA replication also could contribute to the pathogenesis of HCC. The alteration of transcription levels was noted in a large number of genes implicated in metabolism, whereas a profile change of others might represent a status of dedifferentiation of the malignant hepatocytes, both considered as potential markers of diagnostic value. Notably, the altered transcriptome profiles in HCC could be correlated to a number of chromosome regions with amplification or loss of heterozygosity, providing one of the underlying causes of the transcription anomaly of HCC.

[The influence of hydraulic characteristics on wastewater purifying efficiency in vertical flow constructed wetlands]

The hydraulic characteristics of vertical flow constructed wetlands was investigated, and the influence of these characteristics on wastewater purifying efficiency was studied as an emphasis. The results of the experiments in small scale plots and medium scale plots showed the plant roots, with the physical and biological effects, play a significant role in hydraulics and the wastewater purifying efficiency. The other characteristics such as retention time, effluent velocity and influent load also directly affect the wastewater purifying efficiency of constructed wetland. To get a better understanding of the hydraulics will be crucial to the improvement of purifying efficiency and facilitate the practical use of constructed wetland.

[Experimental study on effect of zenggu-I, -II, -III on osteoblast in vitro]

OBJECTIVE

To investigate the effect of Zenggu (ZG)-I, -II and -III on osteoblast (OB) cultured in vitro.

METHODS

OB was isolated from calvaria of 22-day-old fetal SD rats by means of modified sequential collagenase digestion and incubated in RM1640 medium and the cell morphology was observed by alkaline phosphatase (ALP) staining. Different concentrations of ZG-I, -II and -III were added to the OB and incubated. The effect of ZG on the proliferation and osteogenesis of OB was monitored by MTT analysis, BGP content radioimmunoassay, ALP activity and calcium contents determination.

RESULTS

The BGP, ALP, and calcium contents of the cultured OB cells as well as the cell proliferation were higher in ZG-III group than those in the other groups (P < 0.05) in a dose-dependent manner. It suggested that ZG-III could promote the proliferation and osteogenesis of OB, but ZG-I and ZG-II had insignificant influence on OB cultured in vitro.

CONCLUSION

ZG-III could promote the OB proliferation and bone formation, ZG-I, -II, -III sequential therapy could effectively prevent and treat osteoporosis and promote the bone formation.

Characterization of the genomic structure and tissue-specific promoter of the human nuclear receptor NR5A2 (hB1F) gene

The human homologue of the Drosophila melanogaster orphan nuclear receptor fushi tarazu factor 1 (Ftz-F1), NR5A2 (hB1F), was initially identified as a regulatory factor that binds and activates enhancer II of hepatitis B virus. NR5A2 (hB1F) is expressed specifically in pancreas and liver, playing important roles in the regulation of several liver-specific genes. A detailed analysis on the genomic structure and promoter activity will greatly promote future studies on the function of the NR5A2 (hB1F) gene. In this report, a bacterial artificial chromosome clone and several phage clones covering the NR5A2 (hB1F) gene were isolated and the complete genomic sequence was obtained. Alignment of different cDNAs of the NR5A2 (hB1F) gene with the genomic sequence facilitated the delineation of its structural organization, which spans over 150 kb and consists of eight exons interrupted by seven introns. RT-PCR and 3'-RACE revealed that utilization of two polyadenylation signals results in the 3.8 and 5.2 kb transcripts that were observed previously. The transcription start site of the NR5A2 (hB1F) gene was mapped downstream of a canonical TATA box. An upstream fragment containing binding sites for several liver-specific and ubiquitous transcription factors exhibits hepatocyte-specific promoter activity. Transient transfections indicated that hepatocyte nuclear factors HNF1 and HNF3beta could activate NR5A2 (hB1F) promoter.

Map position and expression of the genes in the 38 region of Drosophila

With the completion of the Drosophila genome sequence, an important next step is to extract its biological information by systematic functional analysis of genes. We have produced a high-resolution genetic map of cytological region 38 of Drosophila using 41 deficiency stocks that provide a total of 54 breakpoints within the region. Of a total of 45 independent P-element lines that mapped by in situ hybridization to the region, 14 targeted 7 complementation groups within the 38 region. Additional EMS, X-ray, and spontaneous mutations define a total of 17 complementation groups. Because these two pools partially overlap, the completed analysis revealed 21 distinct complementation groups defined by point mutations. Seven additional functions were defined by trans-heterozygous combinations of deficiencies, resulting in a total of 28 distinct functions. We further produced a developmental expression profile for the 760 kb from 38B to 38E. Of 135 transcription units predicted by GENSCAN, 22 have at least partial homology to mobile genetic elements such as transposons and retroviruses and 17 correspond to previously characterized genes. We analyzed the developmental expression pattern of the remaining genes using poly(A)(+) RNA from ovaries, early and late embryos, larvae, males, and females. We discuss the correlation between GENSCAN predictions and experimentally confirmed transcription units, the high number of male-specific transcripts, and the alignment of the genetic and physical maps in cytological region 38.

[Total water pollution load determining on Tianxi catchment area in Shenyang city]

This paper analysed and determined the total water pollution load of Tianxi catchment area in Shenyang city systematically; by giving the reliability measurement to the total pollution load, put forward the suggestions to improve the system information reliability. It was found that to strengthen monitoring and investigation for the pumping station is of great advantage to control the pollutants of heavy metals, moreover, by adding monitoring to the Huanglatuozi section of Xi river, not only can the pollution load be identified clearly but also organic pollutants can be controlled more accurately and timely.

Genomic sequence and expression analyses of human chromatin assembly factor 1 p150 gene

Chromatin assembly factor-1 (CAF-1) plays essential roles in eukaryotic chromatin assembly during DNA replication (Smith and Stillman, 1989. Cell 58, 15-25), (Krude, 1999. Eur. J. Biochem. 263, 1-5). Its p150 subunit, involved in interaction with histone H3 and H4, is critical to the CAF-1 nucleosome assembly activity. In this study, we sequenced a 96-kb genomic DNA region that includes a 42.8-kb CAF-1 p150 subunit gene (CHAF1A), and a 41.1-kb EEN gene. A scripted bioinformatics analysis pipeline (research agent) has been set up to annotate the BAC sequence with a set of integrated algorithms. The CAF-1 p150 subunit gene contains 15 exons and 14 introns. The promoter region is characterized by deletional analyses, revealing a potential repressor. Tissue-correlated alternative splicing forms of the transcript was initially identified by EST clustering analysis, then confirmed by RT-PCR which resulted more splicing forms than computational prediction.

Dentinogenesis imperfecta 1 with or without progressive hearing loss is associated with distinct mutations in DSPP

Dentinogenesis imperfecta 1 (DGI1, MIM 125490) is an autosomal dominant dental disease characterized by abnormal dentin production and mineralization. The DGI1 locus was recently refined to a 2-Mb interval on 4q21 (ref. 1). Here we study three Chinese families carrying DGI1. We find that the affected individuals of two families also presented with progressive sensorineural high-frequency hearing loss (gene DFNA39). We identified three disease-specific mutations within the dentin sialophosphoprotein gene (DSPP) in these three families. We detected a G-->A transition at the donor-splicing site of intron 3 in one family without DFNA39, a mutation predicted to result in the skipping of exon 3. In two other families affected with both DGI1 and DFNA39, however, we identified two independent nucleotide transversions in exons 2 and 3 of DSPP, respectively, that cause missense mutations of two adjacent amino-acid residues in the predicted transmembrane region of the protein. Moreover, transcripts of DSPP previously reported to be expressed specifically in teeth are also detected in the inner ear of mice. We have thus demonstrated for the first time that distinct mutations in DSPP are responsible for the clinical manifestations of DGI1 with or without DFNA39.