Toward the framework and implementation for clearance of materials from regulated facilities

The disposition of solid materials from nuclear facilities has been a subject of public debate for several decades. The primary concern has been the potential health effects resulting from exposure to residual radioactive materials to be released for unrestricted use. These debates have intensified in the last decade as many regulated facilities are seeking viable management decisions on the disposition of the large amounts of materials potentially containing very low levels of residual radioactivity. Such facilities include the nuclear weapons complex sites managed by the U.S. Department of Energy, commercial power plants licensed by the U.S. Nuclear Regulatory Commission (NRC), and other materials licensees regulated by the NRC or the Agreement States. Other facilities that generate radioactive material containing naturally occurring radioactive materials (NORM) or technologically enhanced NORM (TENORM) are also seeking to dispose of similar materials that may be radioactively contaminated. In contrast to the facilities operated by the DOE and the nuclear power plants licensed by the U.S. Nuclear Regulatory Commission, NORM and TENORM facilities are regulated by the individual states. Current federal laws and regulations do not specify criteria for releasing these materials that may contain residual radioactivity of either man-made or natural origin from regulatory controls. In fact, the current regulatory scheme offers no explicit provision to permit materials being released as "non-radioactive," including those that are essentially free of contamination. The only method used to date with limited success has been case-by-case evaluation and approval. In addition, there is a poorly defined and inconsistent regulatory framework for regulating NORM and TENORM. Some years ago, the International Atomic Energy Agency introduced the concept of clearance, that is, controlling releases of any such materials within the regulatory domain. This paper aims to clarify clearance as an important disposition option for solid materials, establish the framework and basis of release, and discuss resolutions regarding the implementation of such a disposition option.

Effect of the rhg1 Gene on Population Development of Heterodera glycines

The effect of the rhg1 gene on equilibrium population densities (E) and reproduction factors (Rf) of Heterodera glycines was studied by comparing the nematode population development on two near-isogenic soybean lines (NIL), differing at the rhg1 locus. The NIL were inoculated with a series of initial egg densities (Pi) in the greenhouse. The relationships between final population densities (Pf = females per plant or eggs per plant) or Rf (final egg density/Pi) on both NIL and Pi were adequately described by quadratic models. The rhg1 gene suppressed Pf and Rf at all Pi of a population of H. glycines race 3 (HG Type 0-); E and maximum Rf were higher on the NIL-S line than on the NIL-R line. After two generations of culture of the race 3 population on the NIL-R line, the population selected by the rhg1 gene (R-eggs) had higher Pf and Rf on the NIL-R line than the population cultured on the NIL-S line (S-eggs) at all Pi. Both R-eggs and S-eggs produced similar egg numbers on the NIL-S line, which was higher than the egg number of either population on the NIL-R line at all Pi. The ratio of E in female numbers on the NIL-R line to E on the NIL-S line increased from 29% for the original race 3 population (S-eggs) to 46% for the rhg1-selected population (R-eggs). Regardless of different egg sources, a trend of increase in the number of eggs per female with the rise of Pi was observed on the NIL-S line. In contrast, female fecundity of both populations declined with the increase of Pi on the NIL-R line. At most inoculum densities, the highest number of eggs per female was observed on the NIL-S line inoculated with the R-eggs, whereas the lowest number of eggs per female was detected on the NIL-R line inoculated with the S-eggs. This study demonstrated that the E and maximum Rf determined by the quadratic models are useful measurements of plant resistance to nematodes.

Activation of RNA polymerase I transcription by hepatitis C virus core protein

The hepatitis C virus (HCV) core protein has been implicated in the transregulation of various RNA polymerase (Pol) II dependent genes as well as in the control of cellular growth and proliferation. In this study, we show that the core protein, whether individually expressed or produced as part of the HCV viral polyprotein, is the only viral product that has the potential to activate RNA Pol I transcription. Deletion analysis demonstrated that the fragment containing the N-terminal 1-156 residues, but not the 1-122 residues, of HCV core protein confers the same level of transactivation activity as the full-length protein. Moreover, the integrity of the Ser(116) and Arg(117) residues of HCV core protein was found to be critical for its transregulatory functions. We used DNA affinity chromatography to analyze the human ribosomal RNA promoter associated transcription machinery, and the results indicated that recruitment of the upstream binding factor and RNA Pol I to the ribosomal RNA promoter is enhanced in the presence of HCV core protein. Additionally, the HCV core protein mediated activation of ribosomal RNA transcription is accompanied by the hyperphosphorylation of upstream binding factor on serine residues, but not on threonine residues. Moreover, HCV core protein is present within the RNA Pol I multiprotein complex, indicating its direct involvement in facilitating the formation of a functional transcription complex. Protein-protein interaction studies further indicated that HCV core protein can associate with the selectivity factor (SL1) via direct contact with a specific component, TATA-binding protein (TBP). Additionally, the HCV core protein in cooperation with TBP is able to activate RNA Pol II and Pol III mediated transcription, in addition to RNA Pol I transcription. Thus, the results of this study suggest that HCV has evolved a mechanism to deregulate all three nuclear transcription systems, partly through targeting of the common transcription factor, TBP. Notably, the ability of the HCV core protein to upregulate RNA Pol I and Pol III transcription supports its active role in promoting cell growth, proliferation, and the progression of liver carcinogenesis during HCV infection.

The Cytological Mechanism of Low Fertility in the Naked Seed Rice

The low fertility of naked seed rice (NSR) was investigated by the following observations: somatic chromosome constitute, behavior of pollen mother cells (PMCs), the germination of mature pollen grains, the development of male and female gametes and the structure of the anther opening. The results indicated that somatic chromosomal number was 2n = 24, behavior of PMCs were normal and most of pollen grains could regularly develop further to mature male gametophytes in NSR. And dehiscence chamber and thickened endothecium cell (TEC) in numerous anthers of the NSR were developed abnormally after dicaryotic phase, result in few anthers complete opening and most partly opening or failure to opening, therefore much fewer of pollen grains attach on the stigma as compared with normal variety. Furthermore most of embryo sacs possessed abnormal structure and were sterile. All of above illustrated that the failure of the anther opening and the abortion of female gametophyte were main factors controlling the low seed-setting rate of the NSR.

Modulation of p53 transcription regulatory activity and post-translational modification by hepatitis C virus core protein

Oncogenic virus proteins often target to tumor suppressor p53 during virus life cycle. In the case of hepatitis C virus (HCV) core protein, it has been shown to affect p53-dependent transcription. Here, we further characterized the in vitro and in vivo interactions between HCV core protein and p53 and showed that these two proteins colocalized in subnuclear granular structures and the perinuclear area. By use of a reporter assay, we observed that while low level of HCV core protein enhanced the transactivational activity of p53, high level of HCV core protein inhibited this activity. In both cases, however, HCV core protein increased the p53 DNA-binding affinity in gel retardation analyses, likely due to the hyperacetylation of p53 Lys(373) and Lys(382) residues. Additionally, HCV core protein, depending on its expression level, had differential effects on the Ser(15) phosphorylation of p53. Moreover, HCV core protein could rescue p53-mediated suppressive effects on both RNA polymerase I and III transcriptions. Collectively, our results indicate that HCV core protein targets to p53 pathway via at least three means: physical interaction, modulation of p53 gene regulatory activity and post-translational modification. This feature of HCV core protein, may potentially contribute to the HCV-associated pathogenesis.

Automatic Sensor Placement for Model-Based Robot Vision

This paper presents a method for automatic sensor placement for model-based robot vision. In such a vision system, the sensor often needs to be moved from one pose to another around the object to observe all features of interest. This allows multiple three-dimensional (3-D) images to be taken from different vantage viewpoints. The task involves determination of the optimal sensor placements and a shortest path through these viewpoints. During the sensor planning, object features are resampled as individual points attached with surface normals. The optimal sensor placement graph is achieved by a genetic algorithm in which a min-max criterion is used for the evaluation. A shortest path is determined by Christofides algorithm. A Viewpoint Planner is developed to generate the sensor placement plan. It includes many functions, such as 3-D animation of the object geometry, sensor specification, initialization of the viewpoint number and their distribution, viewpoint evolution, shortest path computation, scene simulation of a specific viewpoint, parameter amendment. Experiments are also carried out on a real robot vision system to demonstrate the effectiveness of the proposed method.

Dynamic three-dimensional reconstruction and modeling of cardiovascular anatomy in children with congenital heart disease using biplane angiography

Modeling and simulation of cardiovascular biomechanics and fluid dynamics from patient-specific data is a continuing topic of research investigation. Several methodologies utilizing CT, MRI and ultrasound to re-create the three-dimensional anatomy of the cardiovascular system have been examined. Adaptation of these models to pediatric applications has not been studied as extensively. There is significant need for such techniques in pediatric congenital heart disease since local anatomy may exhibit highly unusual geometry, and three-dimensional information would be of significant use for surgical and interventional planning, biomechanical and fluid dynamic simulation, and patient counseling. We report here on the adaptation and application of a three-dimensional reconstruction technique that utilizes bi-plane angiographic images as the base data sets. The method has been validated in a variety of adult imaging situations including coronary artery imaging and intervention. The method uses a skeletonization approach whereby local centerline, diameter, branching and tortuosity of the vasculature are obtained to create the three-dimensional model. Ten patients with a variety of etiology were imaged and 3D reconstructions were obtained. Excellent images were obtained of complex anatomy including the highly branched pulmonary vasculature and Fontan surgical connections. The data were then translated into solid and surface models to facilitate viewing, export into computational fluid dynamic grids, and into files suitable for stereo lithography fabrication (STL). This method appears promising for the dynamic study of complex cardiovascular anatomy found in congenital heart disease. Optimization of the method to facilitate on-line reconstruction and simulation are currently ongoing.

Inhibition of the proliferation of smooth muscle cells from human coronary bypass vessels by vasonatrin peptide

Abnormal proliferation of vascular smooth muscle cells (VSMCs) is known to be a key event in the development of atherosclerosis and restenosis. The present study examined the effect of a novel synthetic natriuretic peptide, vasonatrin peptide (VNP), on norepinephrine (NE)-induced proliferation of VSMCs from coronary bypass vessels. Human VSMCs were isolated from an internal mammary artery (IMA) and saphenous vein (SV) by explant culture and stimulated with NE. MTT assay and [3H] thymidine-incorporation were undertaken to analyze cell proliferation and radioimmunoassay was used to determine the level of intracellular cyclic 3',5'-guanosine monophosphate (cyclic GMP). NE (10(-8) - 10(-7) mol/l) had a mitogenic effect in human VSMCs from both SV and IMA. However, NE-stimulated proliferation of VSMCs from SV was greater than that from IMA. Furthermore, low concentration of NE (10(-10) mol/l) promoted cell growth in SV-derived cells but not in IMA-derived cells. VNP (10(-8) - 10(-6) mol/l) reduced NE-induced cell proliferation and increased intracellular cyclic GMP, which were abrogated by HS-142-1. In addition, the growth inhibition of VNP was mimicked by 8-bromo-cGMP. These results indicate that VNP has a significant inhibitory effect on NE-stimulated proliferation of human VSMCs from both IMA and SV, which is mediated by guanylate cyclase-linked receptors by increasing cyclic GMP.

Inhibition of the proliferation of smooth muscle cells from human coronary bypass vessels by vasonatrin peptide

Abnormal proliferation of vascular smooth muscle cells (VSMCs) is known to be a key event in the development of atherosclerosis and restenosis. The present study examined the effect of a novel synthetic natriuretic peptide, vasonatrin peptide (VNP), on norepinephrine (NE)-induced proliferation of VSMCs from coronary bypass vessels. Human VSMCs were isolated from an internal mammary artery (IMA) and saphenous vein (SV) by explant culture and stimulated with NE. MTT assay and [3H] thymidine-incorporation were undertaken to analyze cell proliferation and radioimmunoassay was used to determine the level of intracellular cyclic 3’,5’-guanosine monophosphate (cyclic GMP). NE (10-8 - 10-7 mol/l) had a mitogenic effect in human VSMCs from both SV and IMA. However, NE-stimulated proliferation of VSMCs from SV was greater than that from IMA. Furthermore, low concentration of NE (10-10 mol/l) promoted cell growth in SV-derived cells but not in IMA-derived cells. VNP (10-8 - 10-6 mol/l) reduced NE-induced cell proliferation and increased intracellular cyclic GMP, which were abrogated by HS-142-1. In addition, the growth inhibition of VNP was mimicked by 8-bromo-cGMP. These results indicate that VNP has a significant inhibitory effect on NE-stimulated proliferation of human VSMCs from both IMA and SV, which is mediated by guanylate cyclase-linked receptors by increasing cyclic GMP.

Fungal Parasitism of Heterodera glycines Eggs as Influenced by Egg Age and Pre-colonization of Cysts by Other Fungi

The objective of this study was to determine the effect of egg age and pre-colonization of cysts by a saprophytic or parasitic fungus on parasitism of Heterodera glycines eggs by other parasitic fungi. In agar and in soil tests, fungi generally parasitized more eggs in early developmental stages than eggs containing a juvenile. The effect of pre-colonization of cysts by a fungus on parasitism of eggs by other fungi depended on the fungi involved. In most cases, pre-colonization of cysts by an unidentified, saprophytic fungal isolate (A-1-24) did not affect parasitism of eggs in the cysts subsequently treated with other fungi. However, pre-colonization of cysts by A-1-24 reduced fungal parasitism of eggs in cysts subsequently treated with Cylindrocarpon destructans isolate 3. In agar tests, pre-colonization of cysts by Chaetomium cochliodes, a saprophytic or weakly parasitic fungus, reduced parasitism of eggs in cysts subsequently treated with Verticillium chlamydosporium Florida isolate, Fusarium oxysporum, Fusarium solani, ARF18, and another sterile fungus. However, in soil tests, pre-colonization of cysts by C. cochliodes had no effect on parasitism of eggs by subsequent fungal parasites. In another test, parasitism of eggs by V. chlamydosporium in cysts was not affected by pre-colonizing fungi C. destructans, F. oxysporum, and F. solani but was reduced by Mortierella sp., Pyrenochaeta terrestris, and C. cochliodes. Parasitism of eggs in cysts by ARF18 was reduced by pre-colonizing fungi C. destructans, F. oxysporum, F. solani, P. terrestris, and C. cochliodes but not Mortierella sp.

Secondary sulphonylurea failure: what pathogenesis is responsible?

Sulphonylurea (SU) stimulates insulin secretion by pancreatic beta-cells and is generally used as a first-line treatment for type 2 diabetes. However, after long-term SU treatment (six months or over), some patients begin to show an increase in blood glucose once again (secondary SU failure). Two theories have been put forward to explain this failure--dysfunction of the proinsulin conversion machinery or insulin resistance. However, the primary pathogenesis behind secondary SU failure still needs to be investigated. Using a reliable technique that specifically identifies intact proinsulin (IPI), total proinsulin (TPI) and specific insulin (SI), this study aims to discover if a defect in the proinsulin converting mechanism plays a role in SU failure. Three groups were recruited for this study: healthy controls (n=8), SU responders (n=38) and secondary SU failures (n= 46). Serum concentrations of insulin-related molecules released in response to a standard glucose challenge test were compared between the groups. It was found that total SI was lower in the patient groups (P<0.05 compared to the control group), while TPI and IPI showed no distinct difference between the three groups (P>0.05). TPI:SI ratio and IPI:SI ratio showed marked increases in the patient groups (P<0.05 compared to control group), with no obvious quantitative difference between SU responders and secondary SU failures (P>0.05). Similar results for the Homa Insulin Resistant Index were found between the two patient groups. Interestingly, blood glucose at 180 mins after glucose challenge was significantly higher in the secondary SU failure group (P<0.05), with no correlation to SI, while the SU responder group showed good correlation between the parameters (P<0.05). We conclude that type 2 diabetes is associated with obvious dysfunction in the proinsulin-converting process and shows severe SI deficiency in responding to glucose challenge. Dysfunction of the proinsulin conversion mechanism was not an extra cause responsible for SU failure.

Energy and enstrophy transfer in decaying two-dimensional turbulence

We present experimental data on the direct enstrophy cascade in decaying two-dimensional turbulence. Velocity and vorticity fields are obtained using particle tracking velocimetry. From those fields we directly compute the enstrophy and energy flux by using a filtering technique inspired by large-eddy simulations. This allows considerable insight into the physical processes of turbulence when compared with structure-function or spectral analysis. The direct cascade of enstrophy is weakly forward, with almost as much backscatter as down-scale enstrophy transfer, whereas the inverse energy cascade is strongly upscale with a modest amount of backscatter.

Case report: diabetic mastopathy

Diabetic mastopathy is a source of confusion with breast carcinoma. The association between mastopathy and Type I diabetes of long duration has been reported, but this clinical condition is poorly recognized since breast examination is not routinely performed in young diabetic patients. Radiologists' awareness of the constellation of findings in diabetic mastopathy may spare patients from undergoing unwarranted surgical biopsies.

Mechanisms for inhibition of hepatitis B virus gene expression and replication by hepatitis C virus core protein

We have demonstrated previously that the core protein of hepatitis C virus (HCV) exhibits suppression activity on gene expression and replication of hepatitis B virus (HBV). Here we further elucidated the suppression mechanism of HCV core protein. We demonstrated that HCV core protein retained the inhibitory effect on HBV gene expression and replication when expressed as part of the full length of HCV polyprotein. Based on the substitution mutational analysis, our results suggested that mutation introduced into the bipartite nuclear localization signal of the HCV core protein resulted in the cytoplasmic localization of core protein but did not affect its suppression ability on HBV gene expression. Mutational studies also indicated that almost all dibasic residue mutations within the N-terminal 101-amino acid segment of the HCV core protein (except Arg(39)-Arg(40)) impaired the suppression activity on HBV replication but not HBV gene expression. The integrity of Arg residues at positions 101, 113, 114, and 115 was found to be essential for both suppressive effects, whereas the Arg residue at position 104 was important only in the suppression of HBV gene expression. Moreover, our results indicated that the suppression on HBV gene expression was mediated through the direct interaction of HCV core protein with the trans-activator HBx protein, whereas the suppression of HBV replication involved the complex formation between HBV polymerase (pol) and the HCV core protein, resulting in the structural incompetence for the HBV pol to bind the package signal and consequently abolished the formation of the HBV virion. Altogether, this study suggests that these two suppression effects on HBV elicited by the HCV core protein likely depend on different structural context but not on nuclear localization of the core protein, and the two effects can be decoupled as revealed by its differential targets (HBx or HBV pol) on these two processes of the HBV life cycle.

Assessment of sediment toxicity by metal speciation in different particle-size fractions of river sediment

Mobility and toxicity of metals associated with sediments are generally affected by metal speciation and granular compositions. Due to the various speciation patterns of heavy metals in sediments, it is not reliable to assess the potential toxicity of heavy metals on the aquatic environment with the total concentrations of heavy metals in sediments. The purposes of this study were to investigate the distribution of metal speciation in different particle-size fractions of sediments collected from two rivers (the Ke-Ya River and Ell-Ren River) in Taiwan, and to assess their potential toxicity to the aquatic ecosystem. Metals in the exchangeable, carbonate-bound and Fe/Mn oxide-bound forms obtained by sequential extraction were considered to be mobile and related with anthropogenic pollution. The degree of metal pollution and potential toxicity of sediments were higher in the lower reaches of both rivers. The metal speciation in sediments had a bimodal distribution over particle-size fractions. Heavy metals were subject to accumulation in the silt/clay fraction (< 25 microm) and coarse sand (420-2,000 microm). By normalizing the sum of the exchangeable, carbonate-bound, and Fe/Mn oxide-bound metals, it suggested that the potential toxicity to the aquatic ecosystem was caused by the fine sediments as well as coarse sediments.

Effects of ferric ion on bioleaching of heavy metals from contaminated sediment

Bioleaching is one of the promising procedures for removal of heavy metals from contaminated sediments. The advantages of this biotechnology are that it is easy, efficient, less costly and friendly to the environment. However, the principal disadvantage of this process is its slow kinetics in metal solubilization, which may limit practical application of the bioleaching process. In order to enhance the rate and efficiency of metal solubilization, the ferric ion was used as a catalytic agent in the bioleaching process. It was found that the sediment pH apparently decreased in the bioleaching after addition of ferric ion. The metal solubilization increased quickly after the addition of ferric ion. The rate of metal solubilization was enhanced by the addition of ferric ion, especially for Cr and Pb. An increase in the amount of ferric ion added increased the final efficiency of metal solubilization. The highest final efficiency of metal solubilization was obtained in the bioleaching with 1 g/L of ferric ion. Besides, the growth of sulfur-oxidizing bacteria was not affected by addition of ferric ion in the bioleaching. It was concluded that the kinetics of metal solubilization were enhanced by addition of ferric ion in the bioleaching process.

Heart rate responses and oxygen consumption during Tai Chi Chuan practice

Tai Chi Chuan (TCC) is a popular Chinese conditioning exercise, however, its exercise intensity remains controversial. The objective of this study was to determine the exercise intensity of Yang TCC by measuring heart rate (HR) responses and oxygen consumption (VO2) during practice. Fifteen men aged 39.9 +/- 9.5 yrs (range 26-56 yrs) participated in this study. Subjects had practiced classical Yang TCC for 5.8 +/- 2.4 years. HR responses and VO2 were measured during practice of TCC by using a K4 telemetry system. Blood lactate was measured before and immediately after TCC practice. Additionally, breath-by-breath measurement of cardiorespiratory function and sequential determination of blood lactate were performed during the incremental exercise of leg cycling. Measurements obtained during the TCC practice and exercise testing were compared to determine the exercise intensity of TCC. While performing TCC, the mean HR of subjects was 140 +/- 10 bpm, and the mean VO2 was 21.4 +/- 1.5 mL x kg(-1) min(-1). Compared with the data of the exercise test, the HR during practice was 58% of the heart rate range. Meanwhile, the VO2 during TCC practice was 55% of the VO2peak. Additionally, the level of blood lactate immediately after TCC practice was 3.8 mM, which reflected the level of lactate during TCC, approximated the onset of blood lactate accumulation (OBLA). The results demonstrate that TCC is an exercise with moderate intensity, and is aerobic in nature.

HCV NS5A interacts with p53 and inhibits p53-mediated apoptosis

Hepatitis C virus (HCV) causes a persistent infection, chronic hepatitis and hepatocellular carcinoma. HCV NS5A, one of non-structural proteins of HCV, was suggested to play a role in oncogenic transformation. Since the tumor suppressor p53 is important for preventing neoplastic transformation, we investigated the functional effects of HCV NS5A on p53. In vitro and in vivo coimmunoprecipitation and confocal microscopy were used to determine the interaction of NS5A and p53. HCV NS5A binds directly to p53 and colocalizes p53 in the perinuclear region. NS5A inhibits transcriptional transactivation by p53 in a dose-dependent manner by use of a reporter assay. Down regulation of endogenous p21/waf1 expression, which is activated by p53 in Hep3B cells, by NS5A was demonstrated by using FLAG- and FLAG-NS5A Hep3B stable cell lines. The effect of NS5A on p53-mediated apoptosis was determined by flow cytometry in both NS5A permanently and transiently transfected Hep3B cells with exogenous p53. The p53-induced apoptosis was abrogated by NS5A and the inhibition effect correlates well with the binding ability of NS5A to p53. In addition, HCV NS5A protein interacts with and colocalizes hTAF(II)32, a component of TFIID and an essential coactivator of p53, in vivo. These results suggest that HCV NS5A interacts with and partially sequestrates p53 and hTAF(II)32 in the cytoplasm and suppresses p53-mediated transcriptional transactivation and apoptosis during HCV infection, which may contribute to the hepatocarcinogenesis of HCV infection.

Rates and characteristics of lower limb amputations in Taiwan, 1997

This study aims to describe the national incidence rate and characteristics of lower limb amputations (LLA) in 1997 from an island-wide database of the national health insurance programme in Taiwan. Some 117,647 discharge records from a sampled database (1 in 20) of the National Health Insurance Research Database were analysed. This study included records (n=171) containing LLA procedures. The LLA procedure rates were obtained by multiplying the number of identified procedures by 20 as the numerator and mid-year total population of Taiwan in 1997 as the denominator. Each procedure was further analysed according to the demographic characteristics of the patients, cause and level of amputation. Summarised gender ratios of LLA procedure rates were obtained by Poisson regression analysis. The crude LLA procedure rate was 18.1 per 100,000 population per year and the crude major LLA procedure rate was 8.8 per 100,000 population per year in Taiwan in 1997. The major cause of LLA procedures was peripheral vascular disease (72%), and the toe was most frequently amputated (48%). The LLA procedure rates, which increased logarithmically with age of patients, were significantly higher in men with a summarised male to female rate ratio of 1.65. The age-standardised LLA procedure rate in Taiwan was lower than that reported in the United States, Finland, the Netherlands, the United Kingdom (Leeds, Middlesborough, and Newcastle), but higher than Spain, Italy, and Japan. The trend of an increasing proportion of PVD-related LLA procedures will prompt the health professionals to develop strategies for LLA prevention.

Associations of plasma aflatoxin B1-albumin adduct level with plasma selenium level and genetic polymorphisms of glutathione S-transferase M1 and T1

Mortality from hepatocellular carcinoma (HCC) is extraordinarily high in Matzu, an island off the coast of Southeastern China. To investigate factors associated with plasma aflatoxin B1 (AFB1)-albumin adduct level, we studied 304 healthy adult residents from Matzu. AFB1-albumin adducts were determined by competitive enzyme-linked immunosorbent assay, hepatitis B surface antigen status by enzyme immunoassay, genotypes of glutathione S-transferase (GST) M1 and T1 by polymerase chain reaction, plasma selenium by atomic absorption spectrometry, and plasma retinol, alpha-tocopherol, alpha-carotene, and beta-carotene levels by high-performance liquid chromatography. Men had higher AFB1-albumin adduct levels than women. GSTM1-nonnull and GSTT1-null genotypes and low plasma selenium level were significantly associated with an increased level of AFB1-albumin adducts among men, whereas age was significantly correlated with adduct level among women. High intake of fermented beans was associated with an increased adduct level among men and women. The inverse associations between plasma selenium level and AFB1-albumin adducts were statistically significant among those with null genotypes of GSTM1 and GSTT1, but not among the nonnull genotypes. This study provides insight into the dietary and genetic factors influencing AFB1-albumin adduct formation in an isolated population with high liver cancer mortality.

Evaluation of Pea and Soybean as Trap Crops for Managing Heterodera glycines

Trap crops that stimulate nematode egg hatching but not reproduction have been reported as an effective means for managing certain nematodes. Studies were carried out at two field sites each year in 1998 and 1999 to evaluate the potential of trapping the soybean cyst nematode (Heterodera glycines) with soybean and pea in the corn year to manage the nematode in Minnesota. The trap crops were planted on the same day as corn at each site and later killed with the herbicide glyphosate. Nematode egg densities were determined at planting, 1 and 2 months after planting, and at harvest. Treatments included four seeding rates (0, 124,000, 247,000, and 494,000 seeds/ha) of resistant soybean as a trap crop and four kill dates (3, 4, 5, and 6 weeks after planting). No effects of the trap-crop and kill-date treatments on H. glycines population density, corn yield, and the followingyear soybean yield were observed at the two locations. In a second study, the experiment included four trap-crop comparisons (resistant soybean at 494,000 seeds/ha, susceptible soybean at 494,000 seeds/ha, pea at 1,482,000 seeds/ha, and no trap crop) and five kill dates (3, 4, 5, 6 weeks after planting, and no-kill). At the Waseca site, egg density at harvest was lower where resistant soybean was grown for 6 weeks and where pea was grown for 5 and 6 weeks compared with where no trap crop was grown. Maintaining pea plants for more than 5 weeks, however, reduced corn yield by 20% at the Waseca site. At the Lamberton site, egg density at harvest was lower where the susceptible soybean was grown for 5 weeks compared with where no trap crop was grown. Even with significant reduction of eggs in some treatments, use of soybean and pea as trap crops in the corn year was not an effective means for managing H. glycines.

c-Jun potentiates the functional interaction between the amino and carboxyl termini of the androgen receptor

The transactivation functions of the human androgen receptor (hAR) are regulated by several accessory factors that can be either positive or negative. One factor that has been previously shown to mediate hAR transactivation is the proto-oncoprotein c-Jun. The positive effect is a primary one, can be exerted by both endogenous and exogenous c-Jun, and requires multiple regions of c-Jun. However, the exact mechanism by which c-Jun exerts its enhancing function is unknown. In this study, we have used a mammalian two-hybrid system to ask if c-Jun influences the ligand-dependent amino- to carboxyl-terminal (N-to-C) interaction of hAR, which is thought to be responsible for the homodimerization of this receptor. Our results show that c-Jun enhances both hAR N-to-C terminal interaction and DNA binding in vitro. We have also tested a panel of c-Jun and c-Fos mutants for their activities on the N-to-C interaction, and the data demonstrate that the activities of these mutants parallel their activities on hAR transactivation. A mutation in the hAR activation function-2 (AF-2) abrogates N-to-C interaction, DNA binding, and transactivation, and these activities are not rescued by exogenous c-Jun. Interestingly, the p160 coactivator TIF2 can stimulate hAR N-to-C interaction, a finding consistent with the effect on hAR transactivation. These data strongly suggest that the hAR N-to-C interaction is the target of c-Jun action, and this activity requires a functional receptor AF-2.

[Construction and analysis of a genetic linkage map of soybean]

A high-density genetic map was constructed with a RILs population (NJRIKY) from a cross of two cultivated soybean Kefeng 1 and Nannong 1138-2, using RFLP, SSR, RAPD and AFLP markers. The map consists of 24 linkage groups, which include 792 genetic markers, and covers 2,320.7 cM with an average genetic distance of 2.9 cM. The higher polymorphsims between two parents were identified with SSR markers. Due to its simplicity and stability, they could be used as anchored marker to integrate different maps constructed with different genetic markers. AFLP marker system is efficient for map construction while it easily form clusters to cause big gaps in the map. A total of 21.7% of markers was found with distorted segregation in the RILs population. The high-density molecular linkage map is fundamental for gene localization, comparative genomics, and QTL mapping of important agronomic traits.

Association of aflatoxin B(1)-albumin adduct levels with hepatitis B surface antigen status among adolescents in Taiwan

Chronic hepatitis B virus (HBV) infection and aflatoxin B(1) (AFB(1)) exposure interact synergetically to induce hepatocellular carcinoma. One suggested mechanism for this interaction is the enhanced activation of AFB(1) in chronically HBV-infected individuals. Whereas no associations between chronic HBV infection and AFB(1)-albumin adducts were observed in several studies in adults, hepatitis B surface antigen (HbsAg)-positive children were found to have elevated adducts in Gambia. To assess the association between chronic HBV infection and AFB(1)-albumin adduct level in Taiwan, 200 junior high school adolescents from 20 townships were assayed for HBsAg and AFB(1)-albumin adducts. The mean AFB(1)-albumin adduct level was higher in HBsAg-positive compared with HBsAg-negative subjects. The association between HBsAg status and AFB(1)-albumin adducts remained after multivariate adjustment. This finding additionally supports the synergetic interaction between HBV and AFB(1), but the mechanism remains to be elucidated.

MILDOS uranium milling dose assessment code update

The MILDOS-AREA code was developed to estimate radiological doses and risks from uranium milling activities. The code has been used for demonstrating radiological compliance regarding the U.S. Nuclear Regulatory Commission's licensing requirements for uranium milling activities. The code was recently updated with an enhanced software package to address the following four areas: regulatory changes, in-situ leaching extraction technologies, software user interfaces, and software distribution technologies via the internet. Users can now specify in-situ leaching processes through a Windows object-based Geographic information System interface with incorporated updated regulation methodologies. The code and documentation are freely distributed through the Internet.

p53 represses androgen-induced transactivation of prostate-specific antigen by disrupting hAR amino- to carboxyl-terminal interaction

Prostate-specific antigen (PSA) is highly overexpressed in prostate cancer. One important regulator of PSA expression is the androgen receptor (AR), the nuclear receptor that mediates the biological actions of androgens. AR is able to up-regulate PSA expression by directly binding and activating the promoter of this gene. We provide evidence here that that this AR activity is repressed by the tumor suppressor protein p53. p53 appears to exert its inhibition of human AR (hAR) by disrupting its amino- to carboxyl-terminal (N-to-C) interaction, which is thought to be responsible for the homodimerization of this receptor. Consistent with this, p53 is also able to block hAR DNA binding in vitro. Our previous data have shown that c-Jun can mediate hAR transactivation, and this appears to result from a positive effect on hAR N-to-C interaction and DNA binding. Interestingly, c-Jun is able to relieve the negative effects of p53 on hAR transactivation, N-to-C interaction, and DNA binding, demonstrating antagonistic activities of these two proteins. Importantly, a p53 mutation found in metastatic prostate cancer severely disrupts the p53 negative activity on hAR, suggesting that the inability of p53 mutants to down-regulate hAR is, in part, responsible for the metastatic phenotype.

Formation of unusual glutamate conjugates of 1-[3-(aminomethyl)phenyl]-N-[3-fluoro-2'-(methylsulfonyl)-[1,1'-biphenyl]-4-yl]-3-(trifluoromethyl)-1H-pyrazole-5-carboxamide (DPC 423) and its analogs: the role of gamma-glutamyltranspeptidase in the biotransformation of benzylamines

The role of gamma-glutamyltranspeptidase (GGT) in transferring glutamate from endogenous glutathione (GSH) to the benzylamine moiety of a compound, such as 1-[3-(aminomethyl)phenyl]-N-[3-fluoro-2'-(methylsulfonyl)-[1,1'-biphenyl]-4-yl]-3-(trifluoromethyl)-1H-pyrazole-5-carboxamide (DPC 423), is described. Studies were performed with structurally related analogs of DPC 423 to demonstrate that this type of reaction was common to compounds possessing a benzylamine group. Synthesizing appropriate standards and confirming by liquid chromatography (LC)/mass spectroscopy and LC/NMR made unambiguous assignments of the structures of glutamate conjugates of DPC 423. The use of stable isotope-labeled GSH for metabolism studies has not been described before. In the present study, we report the novel use of deuterated GSH in conjunction with mass spectral analysis to demonstrate the glutamate transfer to the benzylamines in the presence of GGT. To further demonstrate that the alpha protons on the benzylamines and glutamate (as part of glutathione) were unaffected during the transpeptidation, these protons were replaced with deuterium. Acivicin (AT-125), a potent and selective inhibitor of GGT, was used to abolish the formation of the glutamate conjugates of DPC 423 in vitro and in vivo. This provided further evidence of the role of GGT in forming the glutamate conjugates of benzylamines. This study demonstrated conclusively that GGT was responsible for mediating the transfer of glutamic acid from GSH to the benzylamine moiety of a series of structurally related compounds.

Clinical features of familial gout and effects of probable genetic association between gout and its related disorders

We examined whether the age at onset, gender, arthritic manifestations, and tophus formation in familial gout are different from those in nonfamilial gout, and we also examined the contributory effect of genetic association to the concurrence of hypertriglyceridemia, hypercholesterolemia, type 2 diabetes mellitus (DM), hypertension, obesity, and renal insufficiency with gout in Taiwan. A total of 21,373 gout patients' data from Ho-Ping Gout database were analyzed in this study retrospectively. The clinical and laboratory data were compared between familial and nonfamilial gout. Mean age at onset of gout in familial subjects was significantly 7.5 years lower than that of nonfamilial subjects (40.9 +/- 13.4 v 48.4 +/- 14.2 years, P =.0001), while gender, arthritic severity, and tophus formation were not significantly different between these 2 groups. Familial gout had lower serum triglyceride (TG), total cholesterol (TC), and percentage of hypertension than nonfamilial gout (182.4 +/- 125.3 v 195.9 +/- 135.8 mg/dL, P =.0001; 207.5 +/- 42.5 v 210.4 +/- 48.8 mg/dL, P =.0003; and 19.57% v 22.56%, P <.0001, respectively). Their serum creatinine, body mass index (BMI), and percentage of type 2 DM were not significantly different. Our results demonstrate that familial gout is associated with precocious onset. Furthermore, the contributory effect of genetic association to the concurrence of hyperlipidemia and hypertension with gout is less than that of environmental factors, while the effect of genetic association to the concurrence of obesity, type 2 DM, and renal insufficiency with gout is equivalent to that of environmental factors.

Reactive oxygen species mediate cyclic strain-induced endothelin-1 gene expression via Ras/Raf/extracellular signal-regulated kinase pathway in endothelial cells

Endothelin-1 (Et-1) is a peptide synthesized by endothelial cells (ECs) both in culture and in vivo. Cyclic strain induces gene expression of Et-1, however, the molecular mechanisms remain unclear. Since cyclic strain induces a sustained increase in intracellular reactive oxygen species (ROS), we hypothesized that the ROS could be a modulator in strain-induced Et-1 gene expression. Human umbilical vein ECs (HUVECs) subjected to cyclic strain had increased Et-1 secretion. Pretreatment of HUVECs with antioxidants, catalase (300 U/ml) or 1,3-dimethyl-2-thiourea (DMTU, 0.1 mm), abolished the strain-induced Et-1 release. ECs strained for 6 h had elevated Et-1 mRNA levels. In contrast, ECs treated with catalase or DMTU did not have increase Et-1 mRNA levels stimulated by cyclic strain. Bovine aortic ECs (BAECs) transfected with fusion plasmid containing Et-1 5'-flanking sequence (4.4 kb) and chloramphenicol acetyltransferase reporter gene produced a maximal Et-1 promoter activity after undergoing strain for 6 h, whereas pretreatment with catalase decreased this activity. BAECs cotransfected with a dominant negative mutant of Ras (RasN17), Raf-1 (Raf301), or catalytically inactive mutant of extracellular signal-regulated kinase (mERK2) had inhibited strain-induced Et-1 promoter activity, indicating the Ras/Raf/ERK pathway was involved; moreover, ERK phosphorylation was induced in ECs which were strained. This strain-activated ERK phosphorylation was attenuated in the presence of catalase. Functional analysis of the Et-1 promoter with site-directed mutagenesis indicates that the activator protein-1 (AP-1) binding site had to be within 143 base-pairs upstream of transcription initiation site for strain-induced promoter activity. Pretreatment of ECs with catalase also decreased the strain-induced promoter activity in the minimal construct (-143 bp). Our data demonstrate that strain-induced Et-1 gene expression is modulated by ROS via Ras/Raf/ERK signaling pathway, and indicate the responsiveness of the AP-1 binding site for strain-induced Et-1 expression.

Selective vulnerability of embryonic cell populations to ethanol-induced apoptosis: implications for alcohol-related birth defects and neurodevelopmental disorder

BACKGROUND

Ethanol-induced cell death has been characterized in very few stages of embryogenesis. This investigation comprehensively maps patterns of both programmed and ethanol-induced cell death in the central nervous system and craniofacial region at 0.5-day intervals from gestational day (GD) 6.5 to 11 in mice.

METHODS

A teratogenic dosage of ethanol (2.9 g/kg) or vehicle was administered via two intraperitoneal injections to pregnant C57BL/6J mice at various stages of gestation. Cell death patterns were characterized using Nile blue sulfate vital staining and histological analysis of plastic sections. Confocal laser scanning microscopy of LysoTracker Red-stained specimens allowed for three-dimensional visualization of areas of apoptosis and precise sectional imaging of mouse embryos. Apoptosis was also documented using a TUNEL technique on histological sections.

RESULTS

Normal programmed cell death in control embryos was noted in the prechordal plate region at GD 8, the neuroepithelium of the fourth ventricle and anterior neuropore at GD 9, and within the ganglia of cranial nerves V, VII-VIII, IX, and X at GD 10. Acute maternal ethanol administration 12 hr before examination resulted in a dramatic increase in apoptosis within sites of programmed cell death in the embryo. Moreover, ethanol-exposed specimens exhibited stage-dependent excessive cell death in other distinct cell populations, particularly within the developing central nervous system. Ethanol-induced apoptosis was notable as follows: GD 7.5-neuroectoderm; GD 8-neural plate and primitive streak; GD 9-alar plate and presumptive neural crest of the rostral hindbrain, especially at the mesencephalon/rhombencephalon junction; GD 9.5-10-branchial arches and rhombomeres; and GD 11-diencephalon, basal ganglia, pons, and developing cerebellum.

CONCLUSIONS

The results of this study revealed developmental stage-specific cell populations of the developing brain and craniofacial region that are vulnerable to ethanol-induced apoptosis and provide new insight relative to the genesis of alcohol-related birth defects.

[Influences of melatonin on the growth of HELA cells]

AIM

To investigate the influence of melatonin (MT) on growth of HeLa cells in vitro.

METHODS

The antiproliferation activities of MT were evaluated on HeLa cells by means of trypan blue dye exclusion and MTT vital staining. The morphological changes of MT on HeLa cells were observed under transmission electron microscope. Cell division cycle influenced by MT was assessed by a flow cytometer.

RESULTS

MT produced a certain inhibition on HeLa cells at the concentration of 2 mmol.L-1 and prolonged the time of double amount (TD). The fraction of cells inhibited was 61.0%. The IC50 of HeLa cells exposed to MT for 96 h was 2.039 mmol.L-1. The flow cytometric analyses showed that exposure to MT for 72 h reduced the number of HeLa cells in phase S. Under electronic microscope, the HeLa cells exposed to MT for 72 h displayed morphological changes of necrosis, apoptosis, more heterochromosome and less somatic chromosome.

CONCLUSION

MT showed certain influence on HeLa cells. Its mechanism may probably be attributable to reduction of the number of cells in phase S.

Bone morphogenetic protein-6 reduces ischemia-induced brain damage in rats

BACKGROUND AND PURPOSE

Bone morphogenetic protein-6 (BMP6) and its receptors are expressed in adult and fetal brain. Receptors for BMP6 are upregulated in adult brain after injury, leading to the suggestion that BMP6 is involved in the physiological response to neuronal injury. The purpose of this study was to determine whether there was a neuroprotective effect of BMP6 in vivo and in vitro.

METHODS

Lactate dehydrogenase and microtubule-associated protein-2 (MAP-2) activities were used to determine the protective effect of BMP6 against H(2)O(2) in primary cortical cultures. The neuroprotective effects of BMP6 were also studied in chloral hydrate-anesthetized rats. BMP6 or vehicle was injected into right cerebral cortex before transient right middle cerebral artery (MCA) ligation. Animals were killed for triphenyl-tetrazolium chloride staining, caspase-3 immunoreactivity and enzymatic assays, and TUNEL assay. A subgroup of animals were used for locomotor behavioral assays.

RESULTS

Application of H(2)O(2) increased lactate dehydrogenase activity and decreased the density of MAP-2(+) neurons in culture. Both responses were attenuated by BMP6 pretreatment. Complementary in vivo studies showed that pretreatment with BMP6 increased motor performance and generated less cerebral infarction induced by MCA ligation/reperfusion in rats. Pretreatment with BMP6 did not alter cerebral blood flow or physiological parameters. There was decreased ischemia-induced caspase-3 immunoreactivity, caspase-3 enzymatic activity, and density of TUNEL-positive cells in ischemic cortex in BMP6-treated animals.

CONCLUSIONS

BMP6 reduces ischemia/reperfusion injury, perhaps by attenuating molecular events underlying apoptosis.

Programmed cell death in extraocular muscle tendon/sclera precursors

PURPOSE

This study was designed to examine the occurrence of natural cell death in the periocular mesenchyme of mouse embryos.

METHODS

Vital staining with LysoTracker Red and Nile blue sulfate as well as terminal nick end labeling (TUNEL) were utilized to identify apoptotic cell death in whole and histologicaly sectioned gestational day 10.5 to 14 mouse embryos. Laser scanning confocal microscopy was used to provide a three dimensional representation of the cell death pattern. Immunohistochemical staining for neural crest and myoblast populations was utilized to indicate the cell population undergoing apoptosis.

RESULTS

Programmed cell death was evident in the developing rectus muscle tendons/sclera on gestational days 11 through 12.5 (corresponding to the weeks 5-6 of human development). Although each of these peripheral periocular condensations has readily apparent amounts of apoptosis, the pattern of cell death varied among them. Cell death was most apparent in the superior rectus tendon primordium, while that for the lateral rectus had the least evidence of apoptosis.

CONCLUSIONS

Although apoptosis was readily evident in the periocular mesenchyme in distinct regions located medial and distal to the developing rectus muscles, programmed cell death in these sites has not previously been reported. New imaging techniques coupled with stains that evidence apoptotic cell death have made it possible to define this tissue as a prominent region of programmed cell death. Although neuronal tissues, including particular regions of the developing eye, are well recognized as sites of programmed cell death, description of this phenomenon in the extraocular tendon/sclera precursors is novel.

Bioleaching of heavy metals from sediment: significance of pH

Bioleaching process, which causes acidification and solubilization of heavy metals, is one of the promising methods for removing heavy metals from contaminated sediments. The solubilization of heavy metals from contaminated sediments is governed by the sediment pH. In the present study, the significance of pH in bioleaching of heavy metals from contaminated sediment was evaluated at different solid contents of sediments in a bench-scale reactor. Results showed that a temporal change of pH in the bioleaching process was effected by the buffering capacity of the sediment particulates. The variations of pH in this bioleaching process were calculated by a modified logistic model. It was observed that solubilization of heavy metals from sediments is highly pH-dependent. In addition, a non-linear equation for metal solubilization relating pH value in the bioleaching process was established. This allows an easier and faster estimate of metal solubilization by measuring pH in the bioleaching process.

Soybean Cyst Nematode Population Development and Associated Soybean Yields of Resistant and Susceptible Cultivars in Minnesota

The soybean cyst nematode (SCN), Heterodera glycines, is a major soybean yield-limiting factor, and the use of resistant cultivars is one of the most effective means to manage the nematode. During the past decade, a number of resistant cultivars in maturity groups I and II have been developed and made available to growers. A total of 47 resistant cultivars and nine susceptible cultivars were evaluated at 15 SCN-infested field sites and two noninfested sites during 1996 to 1998 in Minnesota. As expected, more nematodes developed on susceptible cultivars than on resistant cultivars. Egg density on susceptible cultivars increased by 1.9- to 10.6-fold during the growing season at 12 sites and did not change at the other three sites. Average egg density decreased over time for resistant cultivars at all sites, except where the initial egg density was low (≤455 eggs per 100 cm³ soil). Nematode reproduction factors (Rf = egg density at harvest/egg density at planting) for individual resistant and susceptible cultivars were highly consistent across the eight sites where initial SCN density was more than 1,000 eggs per 100 cm³ soil. Resistance, however, varied among the cultivars, with the average Rf of individual resistant cultivars across the sites ranging from 0.3 to 1.7. Resistant cultivars produced an average yield of 3,082 kg/ha compared with 2,497 kg/ha by susceptible cultivars at eight of 10 sites where egg density at planting was greater than 700 eggs per 100 cm³ soil. In contrast, no difference in yield was observed between resistant and susceptible cultivars at sites where egg density at planting was lower than 500 eggs per 100 cm³ soil. Yield differences between resistant and susceptible cultivars increased with increasing initial SCN egg density. In six fields infested with initial densities of more than 5,000 eggs per 100 cm³ soil, resistant cultivars produced 28.4% (676 kg/ha) more yield on average than susceptible cultivars. Soybean yield increased when cultivars with increasing resistance to the SCN (lower Rf or females formed on roots) were grown in fields infested with SCN. Average relative yield (yield of a cultivar/average yield of all resistant cultivars at a site) of individual resistant cultivars across all SCN-infested sites ranged from 0.76 to 1.10. Yield consistency of soybean cultivars was low among the different sites, indicating that many other factors affected yield. Our results suggest growing resistant cultivars is an effective method to manage SCN in Minnesota while minimizing yield loss due to SCN.

Retroesophageal aortic arch: diagnostic and therapeutic implications of a rare vascular ring

Retroesophageal aortic arch (REAA) can be further divided to right or left retroesophageal aortic arch. The right REAA has right ascending and left descending aorta with retroesophageal segment, whereas the left REAA has left ascending and right descending aorta. The REAA with retroesophageal segment may cause tracheoesophageal compression by the formation of a vascular ring. A total of eight patients were identified from the database from 1996 to 1999. Among them, five were right REAA and three were left REAA. The age at diagnosis varied from 4 days to 16 years (median 8 years). The clinical findings and initial diagnostic investigations, including the chest X-ray, echocardiography and esophagogram, suspected the presence of this anomaly. The diagnosis can be confirmed by ultrafast computed tomography with or without three-dimensional reconstruction. Half of the total patients, two of right and two of left REAA were symptomatic and needed operation. The symptoms related to the retroesophageal aortic arch appeared during infancy and early childhood (six cases), and only rarely in late childhood and adults (two cases). Half of the patients were associated with congenital heart disease, but no specific patterns of congenital heart disease were identified. The sensitivity of the early diagnosis of REAA by chest roentgenogram, echocardiography, esophagogram and angiography was 37% (3/8), 0% (0/7), 100% (1/1) and 60% (3/5), respectively. The sensitivity of ultrafast CT was 100% (8) in delineating both retroesophageal segment and complete vascular ring. Operation to relieve the vascular compression was performed in two cases with right REAA and two with left REAA. Only one died after the operation, due to pulmonary arterial sling and tracheal stenosis. The surviving patients had been asymptomatic during follow up. In conclusion, REAA can be best diagnosed by ultrafast computed tomography with or without three-dimensional reconstruction. If symptomatic, surgery to relieve the compression is effective and safe.

Activation of noradrenergic mechanism attenuates glutamate-induced vasopressor responses in the pons and medulla of cats in vivo

1. Using anesthetized cats, the authors examined the noradrenergic modulation of the glutamate induced pressor and depressor responses in various brainstem areas, including pontine gigantocellular tegmental field (FTG), dorsomedial medulla (DM), rostral ventrolateral medulla (RVLM), and caudal ventrolateral medulla (CVLM). 2. Unilateral microinjection of L-glutamate (Glu, 3 nmol in 30 nL saline) into FTG, DM and RVLM produced an increase in systemic arterial pressure (SAP) and a decrease in heart rate (HR), while into CVLM produced decreases of SAP and HR. 3. Application of norepinephrine (NE) into the pressor areas (0.05 to 5 nmol) did not alter the resting SAP and HR, but significantly attenuated the Glu-induced pressor response with an order of potency: FTG > DM > RVLM. In the depressor CVLM, NE alone produced a dose-dependent decrease of resting SAP and HR, but did not affect the Glu-induced depressor responses. 4. The involvement of different adrenoceptor subtypes was further investigated by application of selective adrenoceptor agonists including phenylephrine (alpha1), clonidine (alpha2), and isoproterenol (beta). Responses to these agonists are similar to those elicited by NE, except that only alpha-adrenoceptor agonists could antagonize the Glu-induced pressor responses of the RVLM. 5. Our observations indicate that NE not only inhibits the pressor mechanisms in various brainstem areas but also elicits a direct depressor response in CVLM. These findings also suggest that NE acts more likely a neurotransmitter, rather than a modulator, in the CVLM.

Reinforcement of acrylic denture base resin by incorporation of various fibers

This study was designed to evaluate improvements in the mechanical properties of acrylic resin following reinforcement with three types of fiber. Polyester fiber (PE), Kevlar fiber (KF), and glass fiber (GF) were cut into 2, 4, and 6 mm lengths and incorporated at concentrations of 1, 2, and 3% (w/w). The mixtures of resin and fiber were cured at 70 degrees C in a water bath for 13 h, then at 90 degrees C for 1 h, in 70 x 25 x 15 mm stone molds, which were enclosed by dental flasks. The cured resin blocks were cut to an appropriate size and tested for impact strength and bending strength following the methods of ASTM Specification No. 256 and ISO Specification No. 1567, respectively. Specimens used in the impact strength test were reused for the Knoop hardness test. The results showed that the impact strength tended to be enhanced with fiber length and concentration, particularly PE at 3% and 6 mm length, which was significantly stronger than other formulations. Bending strength did not change significantly with the various formulations when compared to a control without fiber. The assessment of Knoop hardness revealed a complex pattern for the various formulations. The Knoop hardness of 3%, 6 mm PE-reinforced resin was comparable to that of the other formulations except for the control without fiber, but for clinical usage this did not adversely affect the merit of acrylic denture base resin. It is concluded that, for improved strength the optimum formulation to reinforce acrylic resin is by incorporation of 3%, 6 mm length PE fibers.

Honokiol and magnolol increased hippocampal acetylcholine release in freely-moving rats

Honokiol and magnolol, phenolic compounds isolated from the stem bark of Magnolia officinalis, have been demonstrated to increase choline acetyltransferase activity, inhibit acetylcholinesterase, promote potassium-induced acetylcholine release and exhibit neurotrophic function in in vitro studies. The objective of the present study was to determine the effect of these compounds on hippocampal acetylcholine release in conscious, freely-moving rats. 10(-4) M-10(-6) M of honokiol or magnolol was perfused into rat hippocampus via a dialysis probe. The results showed that at 10(-4) M concentration, honokiol and magnolol markedly increased extracellular acetylcholine release to 165.5+/-5.78% and 237.83+/-9.47% of the basal level, respectively. However, lower concentrations of either compounds failed to elicit significant acetylcholine release. This result suggests that a high dose of honokiol or magnolol may enhance in vivo hippocampal acetylcholine release.

Targeting dendritic cells to enhance DNA vaccine potency

DNA vaccination that can induce both cellular and humoral immune responses has become an attractive immunization strategy against cancer and infection. Dendritic cells (DCs) play a critical role in the induction of immune responses by DNA vaccination. However, a major problem of DNA vaccination is its limited potency, because only a very limited fraction of injected DNA molecules are taken up by DCS: In this study, we describe a novel DNA vaccination strategy to enhance uptake and presentation of antigens by DCS: Specifically, we developed a DNA vaccine based upon expression of a model hepatitis B virus (HBV) e antigen fused to an IgG Fc fragment. After vaccination, the DNA are taken up by cells that produce and secrete the antigen-Fc fusion proteins. The secreted fusion proteins, in addition to inducing B cells, are efficiently captured and processed by DCs via receptor-mediated endocytosis and then presented to the MHC class II and as -I (cross-priming). The results of this study demonstrate that broad enhancement of antigen-specific CD4+ helper, CD8+ cytotoxic T-cell, and B-cell responses can be achieved by this DNA vaccination strategy. Thus, the strategy capable of inducing all arms of the adaptive immunity may provide a novel, generic design for the development of therapeutic and preventive DNA vaccines.

Anterior pituitary failure (panhypopituitarism) with balanced chromosome translocation 46,XY,t(11;22)(q24;q13)

Hypopituitarism is the clinical syndrome that results from failure of the anterior pituitary gland to produce its hormones. Hypopituitarism can result from: (1) intrinsic or primary pituitary disease; (2) intrinsic hypothalamic or secondary pituitary disease; or (3) extrinsic extrasellar or parasellar disease. The etiologies of primary hypopituitarism are miscellaneous. The dominant clinical picture of hypopituitarism in the adult is that of hypogonadism. Reports have associated hypopituitarism with anti-pituitary-antibodies, hereditary syndrome and chromosome defects, but hypopituitarism has rarely been associated with balanced chromosome translocation (11;22)(q24;q13). Here, we describe a case of anterior pituitary failure with balanced chromosome translocation. A 19-year-old Chinese teenager presented with failure of pubertal development and sexual infantilism. On examination, the patient had the classic appearance of hypogonadism. Endocrine studies and three combined pituitary function tests revealed panhypopituitarism. A chromosomal study revealed 46,XY,t(11;22)(q24;q13), a balanced translocation between 11q24 and 22q13. Chest films showed delayed fusion of bilateral humeral head epiphyses and bilateral acromions. Scrotal sonography revealed testes were small bilaterally. Magnetic resonance imaging (MRI) of the sella revealed pituitary dwarfism. The patient received 19 months replacement therapy, including steroids (prednisolone 5 mg each day), L-thyroxine (Eltroxin 100 ug each day), and testosterone enanthate 250 mg every two weeks. His height increased 4 cm with secondary sexual characteristics developed, and muscle power increased.

The relationship between exercise performance and peripheral circulation in patients with peripheral arterial occlusive disease

The exercise performance of patients with peripheral arterial occlusive disease was often impaired. The relationship of exercise performance, daily physical activity, and peripheral circulation was studied. Twenty-five patients with peripheral arterial occlusive disease were recruited; their exercise performance was evaluated with a maximal graded exercise test. A habitual physical activity questionnaire was used to quantify the physical activity level. Measurement of peripheral circulation included the assessment of macrocirculation (ankle-brachial pressure index, calf blood flow by impedance plethysmograph) and microcirculation (cutaneous blood flow, cutaneous temperature, transcutaneous oxygen tension, and cutaneous blood flow responses to iontophoresis). Pearson's product correlation coefficient and multiple linear regression were used in data analysis. Results showed that age, sports index in habitual physical activity questionnaire, and ankle-brachial pressure index were significantly correlated with maximal walking time. Age and sports index were the two major determinants for their exercise performance and accounted for a 61.5% variability.

[Differential accumulation of the new high-affinity phosphate transporter candidated gene fragment in rice roots in response to phosphorus deficiency stress]

Phosphate is a major constraint to crop production, and phosphate uptake in plant is mainly by high-affinity phosphate transporter under phosphate deficiency condition. Using RT-PCR, a 1,178 bp phosphate transporter gene fragment OjPT1 was cloned from roots of Jingxi17 (Oryza sativa L. ssp. japanica) supplied with no phosphate. The comparison of this sequence with ones in GenBank indicated that it shared about 70% similarity at amino acid level with other phosphate transporters in higher plants, such as Arabidopsis thaliana, potate, tamato, Medicago truncatula and Catharanthus roseus, and high similarity with phosphate transporters in Saccharomyces cerevisiae and Neurospora crassa. RT-PCR assay showed that the OjPT1 transcripts were induced under phosphate deficiency condition. This gene fragment OjPT1 has been deposited in GenBank (accession No. AF249619).

Effect of substrate concentration on bioleaching of metal-contaminated sediment

The remediation of metal-contaminated sediment was studied using the bioleaching process with a mixed culture of sulfur-oxidizing bacteria. The effects of substrate concentration (elemental sulfur) on sediment acidification, sulfur oxidation and metal solubilization from contaminated sediment during the bioleaching process were investigated with free-cell suspensions. Sulfur concentration greater than 0.5% (w/v) was found to be inhibitory to bacterial activity and metal solubilization from sediment. The sulfate production was well described by a substrate inhibition expression and Haldane's equation. In addition, an empirical equation related to sulfur concentration was also used to describe the metal solubilization in the bioleaching process.

[Construction of linkage map and mapping resistance gene of Scterotinia scterotiorum in Brassica napus]

Scterotinia scterotiorum (Lib.) de by is a world-wide disease, which seriously decreases the yield and the quality of oil of rapeseed. Mapping resistance genes of S. scterotiorum is of vital effect to breed new elite cultivars resisting the disease. In this paper, we reported that a RAPD linkage map was constructed, including 193 RAPD markers, 19 linkage groups and covering 1,324 cM, by using Mapmaker 3.0. On the basis of map, and resistance genes, Sc1, Sc2 and Sc3, were located in 4th, 8th and 18th linkage groups. Among three QTLs, Sc2 has the characteristics of major gene with explained 29%. The three QTLs together explained about 56% of phenotypic variation.