Conductivity/microstructure study of a pyrochlore-type ordered phase in the compound Zr0.75Ce0.08Nd0.17O1.92

The compound Zr0.75Ce0.08Nd0.17O1.92 was investigated as part of a much larger electrical conductivity/microstructure study of the systems ZrO2-CeO2-M2O3 (where M=Nd, Sm, ..., Yb) [Solid State Ionics (2002)]. Electrical conductivity measurements performed in air at 800 degreesC showed significant conductivity degradation over a period of 200 h. Investigation of the annealed and as-fired specimens by ATEM revealed the presence of an emerging, ordered pyrochlore-type phase within the Zr0.75Ce0.08Nd0.17O1.92 defect-fluorite solid solution at much lower dopant levels than observed previously for zirconia binary systems. (C) 2002 Elsevier Science B.V. All rights reserved.

Leaf area development of ABA-deficient and wild-type peas at two levels of nitrogen supply

The ABA-deficient wilty pea (Pisum sativum L.) and its wild-type (WT) were grown at two levels of nitrogen supply (0.5 and 5.0 mM) for 5-6 weeks from sowing, to determine whether leaf ABA status altered the leaf growth response to N deprivation. Plants were grown at high relative humidity to prevent wilting of the wilty peas. Irrespective of N supply, expanding wilty leaflets had ca 50% less ABA than WT leaflets but similar ethylene evolution rates. Fully expanded wilty leaflets had lower relative water contents (RWC) and were 10-60% smaller in area (according to the node of measurement) than WT leaflets. However, there were no genotypic differences in plant relative leaf expansion rate (RLER). Growth of both genotypes at 0.5 mM N increased the RWC of fully expanded leaflets, but did not alter ethylene evolution or ABA concentration of expanding leaflets. Plants grown at 0.5 mM N showed a 20-30% reduction in RLER, which was similar in magnitude in both wilty and WT peas. Thus, leaf ABA status did not alter the leaf growth response to N deprivation.

Caveolin interacts with the angiotensin II type 1 receptor during exocytic transport but not at the plasma membrane

The mechanisms involved in angiotensin II type 1 receptor (AT(1)-R) trafficking and membrane localization are largely unknown. In this study, we examined the role of caveolin in these processes. Electron microscopy of plasma membrane sheets shows that the AT(1)-R is not concentrated in caveolae but is clustered in cholesterol-independent microdomains; upon activation, it partially redistributes to lipid rafts. Despite the lack of AT(1)-R in caveolae, AT(1)-R. caveolin complexes are readily detectable in cells co-expressing both proteins. This interaction requires an intact caveolin scaffolding domain because mutant caveolins that lack a functional caveolin scaffolding domain do not interact with AT(1)-R. Expression of an N-terminally truncated caveolin-3, CavDGV, that localizes to lipid bodies, or a point mutant, Cav3-P104L, that accumulates in the Golgi mislocalizes AT(1)-R to lipid bodies and Golgi, respectively. Mislocalization results in aberrant maturation and surface expression of AT(1)-R, effects that are not reversed by supplementing cells with cholesterol. Similarly mutation of aromatic residues in the caveolin-binding site abrogates AT(1)-R cell surface expression. In cells lacking caveolin-1 or caveolin-3, AT(1)-R does not traffic to the cell surface unless caveolin is ectopically expressed. This observation is recapitulated in caveolin-1 null mice that have a 55% reduction in renal AT(1)-R levels compared with controls. Taken together our results indicate that a direct interaction with caveolin is required to traffic the AT(1)-R through the exocytic pathway, but this does not result in AT(1)-R sequestration in caveolae. Caveolin therefore acts as a molecular chaperone rather than a plasma membrane scaffold for AT(1)-R.

Skolem-type difference sets for cycle systems

Cyclic m-cycle systems of order v are constructed for all m greater than or equal to 3, and all v = 1(mod 2m). This result has been settled previously by several authors. In this paper, we provide a different solution, as a consequence of a more general result, which handles all cases using similar methods and which also allows us to prove necessary and sufficient conditions for the existence of a cyclic m-cycle system of K-v - F for all m greater than or equal to 3, and all v = 2(mod 2m).

Effect of type of grain and oil supplement on the performance, blood lipoproteins, egg cholesterol and fatty ccids of laying hens

The effects of type of grain (wheat vs. sorghum) and oil supplement/kg diet [0, 20g olive oil (OL), 20g safflower oil (SO), 10 g OL plus 10 g SO (OLSO)], over a 12-week period on the performance, plasma and lipoproteins lipids [cholesterol (C), triglycerides (TG), phospholipid (P)], and yolk C and fatty acids concentrations of laying hens were studied. Hens fed on the sorghum diet had significantly (P

Polymerase chain reaction tests for the identification of Ross River, Kunjin and Murray Valley encephalitis virus infections in horses

Objective To develop and validate specific, sensitive and rapid diagnostic tests using RT-PCR for the detection of Ross River virus (RRV), Kunjin virus (KV) and Murray Valley encephalitis virus (MVEV) infections in horses. Methods Primer sets based on nucleotide sequence encoding the envelope glycoprotein E2 of RRV and on the nonstructural protein 5 (NS5) of KV and MVEV were designed and used in single round PCRs to test for the respective viruses in infected cell cultures and, in the case of RRV, in samples of horse blood and synovial fluid. Results The primer pairs designed for each of the three viruses amplified a product of expected size from prototype viruses that were grown in cell culture. The identity of each of the products was confirmed by nucleotide sequencing indicating that in the context used the RT-PCRs were specific. RRV was detected in serums from 8 horses for which there were clinical signs consistent with RRV infection such that an acute-phase serum sample was taken and submitted for RRV serology testing. The RRV RT-PCR was analytically sensitive in that it was estimated to detect as little as 50 TCID50 of RRV per mL of serum and was specific in that the primer pairs did not amplify other products from the 8 serum samples. The RRV primers also detected virus in three independent mosquito pools known to contain RRV by virus isolation in cell culture. Samples from horses suspected to be infected with KV and MVEV were not available. Conclusion Despite much anecdotal and serological evidence for infection of horses with RRV actual infection and associated clinical disease are infrequently confirmed. The availability of a specific and analytically sensitive RT-PCR for the detection of RRV provides additional opportunities to confirm the presence of this virus in clinical samples. The RTPCR primers for the diagnosis of KV and MVEV infections were shown to be specific for cell culture grown viruses but the further validation of these tests requires the availability of appropriate clinical samples from infected horses.

Purification and characterisation of functional early pregnancy factor expressed in Sf9 insect cells and in Escherichia coli

Early pregnancy factor (EPF) is a secreted protein with growth regulatory and immunomodulatory properties. It is an extracellular form of the mitochondrial matrix protein chaperonin 10 (Cpn10), a molecular chaperone. An understanding of the mechanism of action of EPF and an exploration of therapeutic potential has been limited by availability of purified material. The present study was undertaken to develop a simple high-yielding procedure for preparation of material for structure/function studies, which could be scaled up for therapeutic application. Human EPF was expressed in Sf9 insect cells by baculovirus infection and in Escherichia coli using a heat inducible vector. A modified molecule with an additional N-terminal alanine was also expressed in E coli. The soluble protein was purified from cell lysates via anion exchange (negative-binding mode), cation exchange, and hydrophobic interaction chromatography, yielding similar to42 and 36 mg EPF from 300 ml bacterial and I L Sf9 cultures, respectively. The preparations were highly purified ( greater than or equal to99% purity on SDS-PAGE for the bacterial products and greater than or equal to97% for that of insect cells) and had the expected mass and heptameric structure under native conditions, as determined by mass spectrometry and gel permeation chromatography, respectively. All recombinant preparations exhibited activity in the EPF bioassay, the rosette inhibition test, with similar potency both to each other and to the native molecule. In two in vivo assays of immuno suppressive activity, the delayed-type hypersensitivity reaction and experimental autoimmune encephalomyelitis, the insect cell and modified bacterial products, both with N-terminal additions (acetylation or amino acid), exhibited similar levels of suppressive activity, but the bacterial product with no N-terminal modification had no effect in either assay. Studies by others have shown that N-terminal addition is not necessary for Cpn10 activity. By defining techniques for facile production of molecules with and without immunosuppressive properties, the present studies make it possible to explore mechanisms underlying the distinction between EPF and Cpn10 activity. (C) 2003 Elsevier Inc. All rights reserved.

Variation of bulk properties of anaerobic granules with wastewater type

Development of a granular sludge with high strength, high biological activity and a narrow settling distribution is necessary for optimal operation of high-rate upflow anaerobic treatment systems. Several studies have compared granules produced from different wastewaters but these have largely been from laboratory-fed reactors or compared granules from full-scale reactors fed similar wastewater types. Though two authors have commented on the inferiority of granules produced by a protein-based feed, the properties of these granules have not been characterised. In this paper, granules from full-scale reactors treating fruit and vegetable cannery effluent, two brewery effluents and a pig abattoir (slaughterhouse) were compared in terms of basic composition, size distribution, density, settling velocity, shear strength, and EPS content. The results supported previous qualitative observations by other researchers that indicate granule properties depend more on wastewater type rather than reactor design or operating conditions such as pre-acidification level. The cannery-fed granules bad excellent shear strength, settling distribution and density. Granules from the two brewery-fed reactors had statistically the same bulk properties, which were still acceptable for upflow applications. The protein-grown granule had poor strength and settling velocity. (C) 2001 Elsevier Science Ltd. All rights reserved.

Invertebrate D2 type dopamine receptor exhibits age-based plasticity of expression in the mushroom bodies of the honeybee brain

We have isolated a cDNA clone from the honeybee brain encoding a dopamine receptor, AmDop2, which is positively coupled to adenylyl cyclase. The transmembrane domains of this receptor are 88% identical to the orthologous Drosophila D2 dopamine receptor, DmDop2, though phylogenetic analysis and sequence homology both indicate that invertebrate and vertebrate D2 receptors are quite distinct. In situ hybridization to mRNA in whole-mount preparations of honeybee brains reveals gene expression in the mushroom bodies, a primary site of associative learning. Furthermore, two anatomically distinct cell types in the mushroom bodies exhibit differential regulation of AmDop2 expression. In all nonreproductive females (worker caste) and reproductive males (drones) the receptor gene is strongly and constitutively expressed in all mushroom body interneurons with small cell bodies. In contrast, the large cell-bodied interneurons exhibit dramatic plasticity of AmDop2 gene expression. In newly emerged worker bees (cell-cleaning specialists) and newly emerged drones, no AmDop2 transcript is observed in the large interneurons whereas this transcript is abundant in these cells in the oldest worker bees (resource foragers) and older drones. Differentiation of the mushroom body interneurons into two distinct classes (i.e., plastic or nonplastic with respect to AmDop2 gene expression) indicates that this receptor contributes to the differential regulation of distinct neural circuits. Moreover, the plasticity of expression observed in the large cells implicates this receptor in the behavioral maturation of the bee.

Usefulness of B-type natriuretic peptide in hypertensive patients with exertional dyspnea and normal left ventricular ejection fraction and correlation with new echocardiographic indexes of systolic and diastolic function

B-type natriuretic peptide (BNP) levels increase in systolic heart failure (HF). However, the value of BNP in hypertensive patients with suspected diastolic HF (symptoms suggestive of HF but normal ejection fraction) and its relation to myocardial function in these patients is unclear. We prospectively studied 72 ambulatory hypertensive subjects (40 women, mean age 58 +/- 8 years) with exertional dyspnea and ejection fraction greater than or equal to50%. Diastolic function was evaluated with transmitral and pulmonary venous Doppler, mitral annular velocities (pulsed-wave tissue Doppler), and flow propagation velocity (color M-mode). Systolic function was assessed with strain and strain rate derived from color tissue Doppler imaging. BNP was related to myocardial function and the presence or absence of global diastolic dysfunction. By conventional Doppler criteria, 34 patients had normal left ventricular diastolic function and 38 had isolated diastolic dysfunction. BNP values were higher in patients with diastolic dysfunction (46 +/- 48 vs 20 +/- 20 pg/ml, p = 0.004) and were related independently to blood pressure, systolic strain rate, left atrial function (p < 0.01 for all), and age (p = 0.015). Patients with diastolic dysfunction and pseudonormal filling had higher BNP levels compared with impaired relaxation (89 +/- 47 vs 35 +/- 42 pg/ml, p = 0.001). However, 79% of patients with diastolic dysfunction had BNP levels within the normal range. We conclude that in ambulatory hypertensive patients with symptoms suggestive of mild HF and normal ejection fraction, BNP is related to atrial and ventricular systolic parameters, blood pressure, and age. Although elevated in the presence of diastolic dysfunction, the BNP level mostly is in the normal range and, therefore, has limited diagnostic value in stable patients with suspected diastolic HF. (C) 2003 by Excerpta Medica, Inc.

Structure of the HERG K+ channel S5P extracellular linker - Role of an amphipathic alpha-helix in C-type inactivation

The HERG K+ channel has very unusual kinetic behavior that includes slow activation but rapid inactivation. These features are critical for normal cardiac repolarization as well as in preventing lethal ventricular arrhythmias. Mutagenesis studies have shown that the extracellular peptide linker joining the fifth transmembrane domain to the pore helix is critical for rapid inactivation of the HERG K+ channel. This peptide linker is also considerably longer in HERG K+ channels, 40 amino acids, than in most other voltage-gated K+ channels. In this study we show that a synthetic 42-residue peptide corresponding to this linker region of the HERG K+ channel does not have defined structural elements in aqueous solution; however, it displays two well defined helical regions when in the presence of SDS micelles. The helices correspond to Trp(585)-Ile(593) and Gly(604)-Tyr(611) of the channel. The Trp(585)-Ile(593) helix has distinct hydrophilic and hydrophobic surfaces. The Gly(604)-Tyr(611) helix corresponds to an N-terminal extension of the pore helix. Electrophysiological studies of HERG currents following application of exogenous S5P peptides show that the amphipathic helix in the S5P linker interacts with the pore region of the channel in a voltage-dependent manner.

Effect of central venous catheter type on infections: a prospective clinical trial

This study reports on a block clinical trial of two types of central venous catheters (CVCs): antiseptic-impregnated catheters (AIC) and non-impregnated catheters (non-AIC), on catheter tip colonization and bacteraemia. In total, 500 catheters were inserted in 390 patients over the 18 month study period, 260 (52.0%) AIC and 240 (48.0%) non-AIC. Of these, 460 (92.0%) tips (237 AIC and 223 non-AIC) were collected. While significantly fewer AIC, 14 (5.9%), than non-AIC, 30 (13.5%), catheters were colonized (P < 0.01), there was no difference in the rates of bacteraemias in the two groups (0.8% vs. 2.7%, respectively, P = 0.16). There were 6.87 (95% CI 3.38-14.26) and 16.92 (95% CI 10.61-27.12) colonized AIC and non-AIC catheters, respectively, per 1000 catheter days, a difference that was significant (P < 0.01). However, no difference emerged between bacteraemias in AIC and non-AIC catheters per 1000 catheter days measured at 0.98 (95% CI 0.24-5.54) and 3.38 (95% CI 1.29-9.34), respectively (P = 0.10). Of the 444 CVCs that were sited in the subclavian or jugular veins and had tips collected, significantly more catheters were colonized in the jugular group, 19 (20%), compared with the subclavian group, 24 (6.9%; P less than or equal to 0.01). Overall, the low rates of colonization and bacteraemia may be explained by the population studied, the policies used and the employment of a clinical nurse dedicated to CVC management. (C) 2003 The Hospital Infection Society. Published by Elsevier Science Ltd. All rights reserved.

Decreased coumarin 7-hydroxylase activities and CYP2A6 expression levels in humans caused by genetic polymorphism in CYP2A6 promoter region (CYP2A6*9)

One of seven poor metabolizers of coumarin found in Thai subjects was previously genotyped as heterozygote for the CYP2A6*4 (whole deletion) and CYP2A6*9. Thus, we aimed to investigate the relationship between the genetic polymorphism in the TATA box of the CYP2A6 gene (CYP2A6*9), expression levels of CYP2A6 mRNA and coumarin 7-hydroxylase activities in human livers. Levels of CYP2A6 mRNA were quantified by real-time quantitative reverse transcriptase-polymerase chain reaction. The mean expression levels of CYP2A6 mRNA in individuals with CYP2A6*1/*4, CYP2A6*1/*9 and CYP2A6*4/*9 were 58%, 71% and 21% of the individuals genotyped as CYP2A6*1/*1, respectively. The mean in-vitro coumarin 7-hydroxylase activities in subjects carrying CYP2A6*1/*4, CYP2A6*1/*9 and CYP2A6*4/*9 were 41%, 71% and 12%, respectively, compared to those of the subjects judged as wild-type. Vmax values for coumarin 7-hydroxylation in the liver microsomes from human subjects with genotypes of CYP2A6*1/*1, CYP2A6*1/*4, CYP2A6*1/*9 and CYP2A6*4/*9 were 0.58, 0.26, 0.44 and 0.13 nmol/min/nmol total P450, respectively. CYP2A6 protein levels in human liver microsomes with the CYP2A6*4 and the CYP2A6*9 alleles were markedly decreased. These results suggest that the genetic polymorphism in the promoter region of the CYP2A6 gene (CYP2A6*9) reduced the expression levels of CYP2A6 mRNA and protein in human livers, resulting in the decrease of coumarin 7-hydroxylase activities. Individuals judged as CYP2A6*4/*9 were expected to be poor metabolizers, having extremely low activity of CYP2A6.