bluuebunny/crossref_metadata_2025 huggingface dataset:
Decreased renal sympathetic activity in response to cardiac unloading with nitroglycerin in patients with heart failure*
Authors: Petersson Magnus , Friberg Peter , Lambert Gavin , Rundqvist Bengt
Published: April 2005

Aims:

To examine changes in renal sympathetic outflow in response to cardiac unloading with nitroglycerin (GTN) in patients with chronic heart failure (CHF) and healthy subjects (HS).

Methods and Results:

Renal (RNAsp) and total body (TBNAsp) noradrenaline (NA) spillover were measured with radiotracer methods in 16 patients with CHF (50±3 years, LVEF 20±1%) and nine HS (57±2 years) during right heart and renal vein catheterisation. Low dose GTN decreased mean pulmonary artery pressure (PAm: CHF −7±2 mm Hg, HS −4±1 mm Hg, p<0.05 vs. baseline) but not mean arterial pressure (MAP: CHF −2±1 mm Hg, HS −2±1 mm Hg) and did not affect RNAsp in any of the study groups. High dose GTN lowered MAP (CHF −12±1 mm Hg, HS −12±2 mm Hg, p<0.05 vs. baseline) and PAm (CHF −13±2 mm Hg, HS −5±1 mm Hg, p<0.05 vs. baseline) and was accompanied by a significant reduction in RNAsp only in CHF (1.3±0.1 nmol/min baseline to 0.9±0.2 nmol/min, p<0.05), whereas RNAsp in HS remained unchanged.

Conclusions

In spite of a reduction in both arterial pressure and cardiac filling pressures, renal sympathetic activity decreased in CHF and did not increase in HS. These findings suggest that the altered loading conditions resulting from high‐dose GTN infusion have renal sympathoinhibitory effects.
Multi‐site‐frequency electromechanocardiography for the prediction of ejection fraction and stroke volume in heart failure
Authors: Skrabal Falko , Mayer Harald , Hopfgartner Elke , Gratze Gerfried , Haitchi Gerhard , Holler Albert
Published: April 2005

Background:

Methods for stroke volume (SV) and ejection fraction (EF) measurements require the presence of qualified physicians and are not suited for continuous monitoring.

Aim:

To develop an automated non‐invasive method for the measurement and continuous monitoring of SV and EF.

Methods:

We have designed a method for the measurement of EF and SV using multiple‐site‐impedance (z0) measurements, applying multiple frequencies of 5, 40 and 200 kHz whereby various segments of the human body, including volume changes within these segments, could be defined electrically. The obtained variables were used to train neuronal nets and related by multiple regression analyses to cardiac output (CO) as measured by a partial rebreathing Fick method (COr‐fick) or EF as measured by echocardiography (EFecho), respectively. A total of 129 subjects (48 with normal heart function and 81 with CHF, NYHA I–IV) were investigated.

Results:

The multiply derived values of z0 and of change of impedance (dz/dt) were shown, by multiple regression analysis, to be significantly related to COr‐fick and to EFecho, (total r=0.77, n=35, p<0.001, and r=0.81, n=47, p<0.001, respectively.). By training a neuronal net with the electrical data of 67 (out of 94) subjects, EFecho could be predicted in the remaining 27 subjects which were unknown to the neuronal net with a combined r=0.71 (p<0.001,n=27). In contrast, conventional impedance cardiography (ICG) was unable to predict either COr‐fick or EFecho.

Conclusion:

The new method, which we call multi‐site‐frequency electromechanocardiography (msf‐ELMC) appears promising for the automated electrical measurement of the mechanical heart action in patients with normal and reduced cardiac function.
Inflammation and perturbation of the l‐carnitine system in heart failure
Authors: Vescovo Giorgio , Ravara Barbara , Gobbo Valerio , Libera Luciano Dalla
Published: April 2005

Background:

Heart failure (HF) is accompanied by elevated levels of pro‐inflammatory cytokines. Skeletal muscle myopathy with atrophy of fibres, decreased oxidative metabolism and preferential synthesis of fast myosin heavy chains (MHCs) occurs, which contributes to the worsening of symptoms. l‐Carnitine has been shown to be protective against the apoptosis‐induced atrophy of fibres and fast MHCs shift.

Aims:

To investigate the interrelationship between TNFα and sphingosine (SPH), which induce muscle wastage, and plasma levels of l‐carnitine.

Methods:

We studied 18 heart failure patients and correlated NYHA class and ventricular function with the plasma concentration of these molecules.

Results:

TNFα and SPH levels were raised and correlated with the severity of HF. l‐Carnitine levels were increased in HF patients, but decreased according to the severity of cardiac decompensation.

Conclusions:

The increased levels of l‐carnitine are likely due to release from the damaged muscle, reduced urinary excretion, decreased dietary intake and liver synthesis (malnutrition). It is possible that the cytokine‐induced muscle wastage is not counterbalanced by the beneficial metabolic effects of l‐carnitine, the metabolism of which is profoundly perturbed in CHF. l‐Carnitine supplementation may produce positive effects on the skeletal muscle, as has been shown in animal models of HF.
Incidence of normal values of natriuretic peptides in patients with chronic heart failure and impact on survival: A direct comparison of N‐terminal atrial natriuretic peptide, N‐terminal brain natriuretic peptide and brain natriuretic peptide
Authors: Hülsmann Martin , Berger Rudolf , Mörtl Deddo , Gore Odette , Meyer Brigitte , Pacher Richard
Published: April 2005

Aims

N‐ANP, N‐BNP and BNP are proven to be excellent markers for diagnosis and the prediction of outcome in heart failure patients. Published studies on this subject differ in respect of their design and are therefore difficult to compare. The EuroHeart Failure Survey was undertaken to evaluate the drug prescription rate; the cohort of this survey best reflects clinical practice. The purpose of the present study was to compare the three hormones in clinical practice for the purpose of diagnosis and the prediction of outcome. Attention was focused on patients with normal values and the implications of these on survival.

Methods and results

Of 341 patients recruited in the Austrian centers of the survey, blood samples for the determination of N‐ANP, N‐BNP and BNP were taken from 112 patients. Mortality within the observation period was defined as the endpoint. Normal levels of the hormones were found in 5% of cases for N‐ANP, 25% for N‐BNP and 30% for BNP. The mortality of patients with normal values was low (0%, 3% and 6%, respectively) and occurred late (after more than 23 months). Above‐median levels of all three hormones resulted in a comparable mortality (51% survival for N‐ANP, 50% for BNP and 49% for N‐BNP).

Conclusions

In a clinical setting, the risk stratification for outcome is similar for N‐ANP, N‐BNP and BNP. More importantly, all hormones are reliable parameters to diagnose CHF using normal values as a cut‐point. However, N‐ANP appears to be more sensitve than BNP or N‐BNP.
Temperament and character in primary insomnia
Authors: de Saint Hilaire Zara , Straub Judith , Pelissolo Antoine
Published: April 2005

Recent studies by Cloninger suggest that the temperament dimension of harm avoidance might be related to serotonergic activity. Since serotonergic mechanisms equally play a major role in sleep regulation, we decided to use Cloninger’s psychobiological model of temperament and character to assess whether there is a link between psychophysiologic insomnia and specific personality traits. Chronic insomnia is a common complaint in modern society, and it is still controversial whether insomniacs share specific personality traits. Thirty-two chronic insomniacs (<50 years) were studied. They underwent polysomnography for two consecutive nights and filled out the 226-item self-questionnaire of Temperament and Character Inventory as well as the Hospital Anxiety and Depression scale. (1) Harm avoidance for all subscores was significantly higher in insomniac patients when compared with controls; (2) self-directedness scores were lower in insomniacs; (3) sleep latency was positively correlated to harm avoidance; (4) HA1 (anticipatory worry) was negatively correlated to REM latency. Temperament and Character Inventory is a useful tool in the investigation of chronic insomnia. Serotonergic mechanisms might explain the high incidence of harm avoidance as personality trait in psychophysiologic insomniac patients. Further studies are needed to see whether harm avoidance could be a psychological vulnerability marker for primary insomnia and be used as predictor of SSRI treatment responders.
A hyaluronan synthase suppressor, 4‐methylumbelliferone, inhibits liver metastasis of melanoma cells
Authors: Yoshihara Shuichi , Kon Atsushi , Kudo Daisuke , Nakazawa Hideaki , Kakizaki Ikuko , Sasaki Mutsuo , Endo Masahiko , Takagaki Keiichi
Published: April 2005

4‐Methylumbelliferone (MU) inhibits the cell surface hyaluronan (HA) formation, and that such inhibition results in suppression of adhesion and locomotion of cultured melanoma cells. Here, we examine the effect of MU on melanoma cell metastasis in vivo. MU‐treated melanoma cells showed both decreased cell surface HA formation and suppression of liver metastasis after injection into the mice. Oral administration of MU to mice decreased tissue HA content. These HA knock‐down mice displayed suppressed liver metastasis. Thus, both cell surface HA of melanoma cells and recipient liver HA can promote liver metastasis, indicating that MU has potential as an anti‐metastatic agent.
The nucleocapsid protein of SARS coronavirus has a high binding affinity to the human cellular heterogeneous nuclear ribonucleoprotein A1
Authors: Luo Haibin , Chen Qing , Chen Jing , Chen Kaixian , Shen Xu , Jiang Hualiang
Published: April 2005

The nucleocapsid (N) protein of SARS coronavirus (SARS_CoV) is a major structural component of virions, which appears to be a multifunctional protein involved in viral RNA replication and translation. Heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1) is related to the pre‐mRNA splicing in the nucleus and translation regulation in the cytoplasm. In this report, based on the relevant biophysical and biochemical assays, the nucleocapsid protein of SARS_CoV (SARS_N) was discovered to exhibit high binding affinity to human hnRNP A1. GST pull‐down results clearly demonstrated that SARS_N protein could directly and specifically bind to human hnRNP A1 in vitro. Yeast two‐hybrid assays further indicated in vivo that such binding relates to the fragment (aa 161–210) of SARS_N and the Gly‐rich domain (aa 203–320) of hnRNP A1. Moreover, kinetic analyses by surface plasmon resonance (SPR) technology revealed that SARS_N protein has a specific binding affinity against human hnRNP A1 with K
D at 0.35 ± 0.02 μM (k
on
= 5.83 ± 0.42 × 103
M−1
s−1 and k
off
= 2.06 ± 0.12 × 10−3
s−1). It is suggested that both SARS_N and hnRNP A1 proteins are possibly within the SARS_CoV replication/transcription complex and SARS_N/human hnRNP A1 interaction might function in the regulation of SARS_CoV RNA synthesis. In addition, the determined results showed that SARS_N protein has only one binding domain for interacting with human hnRNP A1, which is different from the mouse hepatitis virus (MHV) binding case where the nucleocapsid protein of MHV (MHV_N) was found to have two binding domains involved in the MHV_N/hnRNP A1 interaction, thereby suggesting that SARS_N protein might carry out a different binding mode to bind to human hnRNP A1 for its further function performance in comparison with MHV_N.
HDM2 negatively affects the Chk2‐mediated phosphorylation of p53
Authors: Bjørling-Poulsen Marina , Meek David , Issinger Olaf-Georg
Published: April 2005

By GST pull downs and co‐immunoprecipitation analyses we found that recombinant Chk2 and HDM2 can form stable complexes in vitro. Chk2/HDM2 complexes were also detected in transfected Cos‐1 cells over‐expressing both proteins. Furthermore, we show that HDM2, as would be expected, severely affects the Chk2‐catalyzed phosphorylation of p53. HDM2 itself is only slightly phosphorylated by Chk2. However, whereas HDM2 inhibits the Chk2‐catalyzed p53 phosphorylation, HDM2 phosphorylation by Chk2 doubles in the presence of p53. The significance of the HDM2 phosphorylation is unknown, but it is possible that it might influence the stability of the HDM2/p53 complex.
Scallop DMT functions as a Ca2+ transporter
Authors: Toyohara Haruhiko , Yamamoto Sayuri , Hosoi Masatomi , Takagi Masaya , Hayashi Isao , Nakao Kenji , Kaneko Shuji
Published: April 2005

We identified a DMT (divalent metal transporter) homologous protein that functions as a Ca2+ transporter. Scallop DMT cDNA encodes a 539‐amino‐acid protein with 12 putative membrane‐spanning domains and has a consensus transport motif in the fourth extracellular loop. Since its mRNA is significantly expressed in the gill and intestine, it is assumed that scallop DMT transports Ca2+ from seawater by the gill and from food by the intestine. Scallop DMT lacks the iron‐responsive element commonly found in iron‐regulatory proteins, suggesting that it is free of the post‐transcriptional regulation from intracellular Fe2+ concentration. Scallop DMT distinctly functions as a Ca2+ transporter unlike other DMTs, however, it also transports Fe2+ and Cd2+ similar to them.
Quantitative aspects of endocytic activity in lipid‐mediated transfections
Authors: Prasad Tekkatte Krishnamurthy , Rangaraj Nandini , Rao Nalam Madhusudhana
Published: April 2005

Variation in transfection efficiency observed in different cell‐types is poorly understood. To investigate the influence of endocytic activity on lipid‐mediated transfections, we have monitored both the processes in 12 different cell‐types. The endocytic activity shows a strong positive correlation (P
< 0.01), with transfection efficiency. Treatment with wortmannin resulted in cell‐type‐dependent inhibition of transfection. Studies on M‐phase cells by confocal microscopy show that compared to interphase cells, uptake of cationic liposomes was substantially reduced. In addition, transfection efficiency of cells in mitotic phase was inhibited by >70% compared to controls. Our study based on several cell‐types demonstrates for the first time that quantitative aspects of endocytosis have decisive influence on the overall process of lipid‐mediated transgene expression.
Functionality of nitrated acetylcholine receptor: The two‐step formation of nitrotyrosines reveals their differential role in effectors binding
Authors: Négrerie Michel , Martin Jean-Louis , Nghiêm Hoàng-Oanh
Published: April 2005

The presence of nitrotyrosines is associated with several neurodegenerative pathologies. We evaluated the functionality of the nicotinic acetylcholine receptor possessing nitrotyrosines. The spectrum of the nitrated receptor displays an absorption band characteristic of ortho‐nitrophenol. The presence of carbamylcholine in the agonist site prevented the effect of nitration by tetranitromethane in some conditions. The nitration occurred with two discrete steps and pointed out the differential involvement of tyrosines in the binding of acetylcholine and neurotoxin. We concluded that at least two residues involved in agonist binding can be nitrated, which bring similar contributions to the binding energy of the neurotransmitter.
Evidence of differential pH regulation of the Arabidopsis vacuolar Ca2+/H+ antiporters CAX1 and CAX2
Authors: Pittman Jon K. , Shigaki Toshiro , Hirschi Kendal D.
Published: April 2005

The Arabidopsis Ca2+/H+ antiporters cation exchanger (CAX) 1 and 2 utilise an electrochemical gradient to transport Ca2+ into the vacuole to help mediate Ca2+ homeostasis. Previous whole plant studies indicate that activity of Ca2+/H+ antiporters is regulated by pH. However, the pH regulation of individual Ca2+/H+ antiporters has not been examined. To determine whether CAX1 and CAX2 activity is affected by pH, Ca2+/H+ antiport activity was measured in vacuolar membrane vesicles isolated from yeast heterologously expressing either transporter. Ca2+ transport by CAX1 and CAX2 was regulated by cytosolic pH and each transporter had a distinct cytosolic pH profile. Screening of CAX1/CAX2 chimeras identified an amino acid domain within CAX2 that altered the pH‐dependent Ca2+ transport profile so that it was almost identical to the pH profile of CAX1. Results from mutagenesis of a specific His residue within this domain suggests a role for this residue in pH regulation.
Catalytic properties of glutathione‐binding residues in a τ class glutathione transferase (PtGSTU1) from Pinus tabulaeformis
Authors: Zeng Qing-Yin , Wang Xiao-Ru
Published: April 2005

Glutathione transferases (GSTs) play important roles in stress tolerance and detoxification in plants. However, there is extremely little information on the molecular characteristics of GSTs in gymnosperms. In a previous study, we cloned a τ class GST (PtGSTU1) from a gymnosperm (Pinus tabulaeformis) for the first time. Based on the N‐terminal amino acid sequence identity to the available crystal structures of plant τ GSTs, Ser13, Lys40, Ile54, Glu66 and Ser67 of PtGSTU1 were proposed as glutathione‐binding (G‐site) residues. The importance of Ser13 as a G‐site residue was investigated previously. The functions of Lys40, Ile54, Glu66 and Ser67 of PtGSTU1 are examined in this study through site‐directed mutagenesis. Enzyme assays and thermal stability measurements on the purified recombinant PtGSTU1 showed that substitution at each of these sites significantly affects the enzyme's substrate specificity and affinity for GSH, and these residues are essential for maintaining the stability of PtGSTU1. The results of protein expression and refolding analyses suggest that Ile54 is involved in the protein folding process. The findings demonstrate that the aforementioned residues are critical components of active sites that contribute to the enzyme's catalytic activity and structural stability.
Interactions of the cytotoxic RNase A dimers with the cytosolic ribonuclease inhibitor
Authors: Naddeo Mariarosaria , Vitagliano Luigi , Russo Aniello , Gotte Giovanni , D‧Alessio Giuseppe , Sorrentino Salvatore
Published: April 2005

Ribonuclease A (RNase A) dimers have been recently found to be endowed with some of the special, i.e., non‐catalytic biological activities of RNases, such as antitumor and aspermatogenic activities. These activities have been so far attributed to RNases which can escape the neutralizing action of the cytosolic RNase inhibitor (cRI). However, when the interactions of the two cytotoxic RNase A dimers with cRI were investigated in a quantitative fashion and at the molecular level, the dimers were found to bind cRI with high affinity and to form tight complexes.
Transfer RNA recognition by class I lysyl‐tRNA synthetase from the Lyme disease pathogen Borrelia burgdorferi
Authors: Ambrogelly Alexandre , Frugier Magali , Ibba Michael , Söll Dieter , Giegé Richard
Published: April 2005

Borrelia burgdorferi and other spirochetes contain a class I lysyl‐tRNA synthetase (LysRS), in contrast to most eubacteria that have a canonical class II LysRS. We analyzed tRNALys recognition by B. burgdorferi LysRS, using two complementary approaches. First, the nucleotides of B. burgdorferi tRNALys in contact with B. burgdorferi LysRS were determined by enzymatic footprinting experiments. Second, the kinetic parameters for a series of variants of the B. burgdorferi tRNALys were then determined during aminoacylation by B. burgdorferi LysRS. The identity elements were found to be mostly located in the anticodon and in the acceptor stem. Transplantation of the identified identity elements into the Escherichia coli tRNAAsp scaffold endowed lysylation activity on the resulting chimera, indicating that a functional B. burgdorferi lysine tRNA identity set had been determined.
READING AND (RE)WRITING CLASS: ELIZABETH GASKELL'SWIVES AND DAUGHTERS
Authors: Boiko Karen
Published: April 2005

His anatomy was philosophic, or transcendent, becausetranscendingthe vision of the eye, it had the vision of the mind, seeing what the eye alone could never see.

—G. H. Lewes, “Life and Doctrine of Geoffroy St. Hilaire”

Scientific material does not have clear boundaries once it enters literature.

—Dame Gillian Beer,Open Fields
Recent ice loss from the Fleming and other glaciers, Wordie Bay, West Antarctic Peninsula
Authors: Rignot E. , Casassa G. , Gogineni S. , Kanagaratnam P. , Krabill W. , Pritchard H. , Rivera A. , Thomas R. , Turner J. , Vaughan D.
Published: April 2005

Satellite radar interferometry data from 1995 to 2004, and airborne ice thickness data from 2002, reveal that the glaciers flowing into former Wordie Ice Shelf, West Antarctic Peninsula, discharge 6.8 ± 0.3 km3/yr of ice, which is 84 ± 30 percent larger than a snow accumulation of 3.7 ± 0.8 km3/yr over a 6,300 km2 drainage basin. Airborne and ICESat laser altimetry elevation data reveal glacier thinning at rates up to 2 m/yr. Fifty km from its ice front, Fleming Glacier flows 50 percent faster than it did in 1974 prior to the main collapse of Wordie Ice Shelf. We conclude that the glaciers accelerated following ice shelf removal, and have been thinning and losing mass to the ocean over the last decade. This and other observations suggest that the mass loss from the northern part of the Peninsula is not negligible at present.
Details of stratification in a sloping bottom boundary layer of Great Meteor Seamount
Authors: van Haren Hans
Published: April 2005

Detailed temperature and current observations show rapid variations in vertical overturning and stratification above Great Meteor Seamount. Classically, steady downwelling interior flow generates a large homogeneous turbulent bottom boundary layer (bbl) and upwelling interior flow generates a small bbl above a sloping bottom. In contrast, the present observations show the dominance of bores and waves in bbl variations above a slope that is non‐critical for internal tidal waves. During the upslope tidal phase a small bbl is preceded by a breaking bore extending up to 50 m. The bore shows many small stratified layers. These small layers organize in two large, strongly stratified layers, one at <10 m, the other at ∼40 m. During the downslope phase only the lower remains. Above it a thick ∼homogeneous layer is observed, which however does not reach the bottom and thus cannot qualify as a bbl having no influence on sediment resuspension.
A simple method to improve ensemble‐based ozone forecasts
Authors: Pagowski M. , Grell G. A. , McKeen S. A. , Dévényi D. , Wilczak J. M. , Bouchet V. , Gong W. , McHenry J. , Peckham S. , McQueen J. , Moffet R. , Tang Y.
Published: April 2005

Forecasts from seven air quality models and ozone data collected over the eastern USA and southern Canada during July and August 2004 are used in creating a simple method to improve ensemble‐based forecasts of maximum daily 1‐hr and 8‐hr averaged ozone concentrations. The method minimizes least‐square error of ensemble forecasts by assigning weights for its members. The real‐time ozone (O3) forecasts from this ensemble of models are statistically evaluated against the ozone observations collected for the AIRNow database comprising more than 350 stations. Application of this method is shown to significantly improve overall statistics (e.g., bias, root mean square error, and index of agreement) of the weighted ensemble compared to the averaged ensemble or any individual ensemble member. If a sufficient number of observations is available, we recommend that weights be calculated daily; if not, a longer training phase will still provide a positive benefit.
Planar double layers in magnetized plasmas: Fine structures and their consequences
Authors: Singh Nagendra , Khazanov Igor
Published: April 2005

Using two‐dimensional electrostatic particle‐in‐cell code, we study the dynamical behavior of planar double layers (DLs) in magnetized plasmas nonuniformly distributed along an ambient magnetic field Bo. The plasma is driven by a magnetic field‐aligned (parallel) potential drop with a polarity appropriate for the return current auroral plasma; the low‐density hot plasma at the top of the simulation plane is positive with respect to the high‐density cold plasma at the bottom. In response to the applied potential drop, a planar double layer rapidly forms at the evolving interface between the cold and hot plasmas. The ions accelerated downward by the DL into the cold plasma generate low‐frequency electrostatic ion cyclotron (EIC) fluctuations; their nonlinear evolution fragments the DL horizontally into filamentary DLs having U‐ and V‐shaped equipotentials like in diverging electrostatic shocks (D‐shocks). The filamentary potential structures have density depletions bounded by high‐density plasma columns. The cold electrons accelerated by the parallel fields inside the DL substructures (DLSS) generate electron holes, which become the dominant feature of the plasma above the regions of the parallel fields. The initial filaments have the size of hot ion Larmor radius, but at latter times the transverse size of the filaments increases as they dynamically evolve both in shape and size with the transverse ion heating. During the process of fragmentation of the initial DL the cold ions undergo considerable transverse acceleration by the perpendicular electric fields in the developing substructures. Those initially cold ions which manage to get above the time‐dependent DLSSs and even the hot ions traversing the region above them are seen to undergo significant heating in both parallel and perpendicular directions by the sustained interactions with the upward moving large‐amplitude electron holes. Relevance of our findings to the physics of the auroral return current plasma is discussed.
Spatial localization of moment deficits in southern California
Authors: Meade Brendan J. , Hager Bradford H.
Published: April 2005

The balance between interseismic elastic strain accumulation and coseismic release defines the extent to which a fault system exhibits a surplus or deficit of large earthquakes. We calculate the regional moment accumulation rate in southern California based on a fault slip rate catalog estimated from a block model of interseismic deformation constrained by GPS measurements. The scalar moment accumulation rate, 17.8 ± 1.1 × 1018N m/yr, is approximately 50% larger than the average moment release rate over the last 200 years. Differences between the accumulated and released elastic displacement fields are consistent with moment deficits that are localized in three regions: the southern San Andreas and San Jacinto faults, offshore faults and the Los Angeles and Ventura basins, and the Eastern California Shear Zone. The moment budget could be balanced by coseismic events with a composite magnitude ofMw≈ 8.
Statistical Prediction of Tissue Fate in Acute Ischemic Brain Injury
Authors: Shen Qiang , Ren Hongxia , Fisher Marc , Duong Timothy Q
Published: April 2005

An algorithm was developed to statistically predict ischemic tissue fate on a pixel-by-pixel basis. Quantitative high-resolution (200 × 200μm) cerebral blood flow (CBF) and apparent diffusion coefficient (ADC) were measured on acute stroke rats subjected to permanent middle cerebral artery occlusion and an automated clustering (ISODATA) technique was used to classify ischemic tissue types. Probability and probability density profiles were derived from a training data set ( n = 6) and probability maps of risk of subsequent infarction were computed in another group of animals ( n = 6) as ischemia progressed. Predictions were applied to overall tissue fate. Performance measures (sensitivity, specificity, and receiver operating characteristic) showed that prediction made based on combined ADC + CBF data outperformed those based on ADC or CBF data alone. At the optimal operating points, combined ADC + CBF predicted tissue infarction with 86%±4% sensitivity and 89%±6% specificity. More importantly, probability of infarct ( PI) for different ISODATA-derived ischemic tissue types were also computed: (1) For the ‘normal’ cluster in the ischemic right hemisphere, PI based on combined ADC + CBF data ( PI[ADC + CBF]) accurately reflected tissue fate, whereas PI[ADC] and PI[CBF] overestimated infarct probability. (2) For the ‘perfusion—diffusion mismatch’ cluster, PI[AdC + CBF] accurately predicted tissue fate, whereas PI[ADC] underestimated and PI[CBF] overestimated infarct probability. (3) For the core cluster, PI[ADC + CBF], PI[ADC], and PI[CBF] prediction were high and similar (~90%). This study shows an algorithm to statistically predict overall, normal, ischemic core, and ‘penumbral’ tissue fate using early quantitative perfusion and diffusion information. It is suggested that this approach can be applied to stroke patients in a computationally inexpensive manner.
Poiseuille flow to measure the viscosity of particle model fluids
Authors: Backer J. A. , Lowe C. P. , Hoefsloot H. C. J. , Iedema P. D.
Published: April 2005

The most important property of a fluid is its viscosity, it determines the flow properties. If one simulates a fluid using a particle model, calculating the viscosity accurately is difficult because it is a collective property. In this article we describe a new method that has a better signal to noise ratio than existing methods. It is based on using periodic boundary conditions to simulate counter-flowing Poiseuille flows without the use of explicit boundaries. The viscosity is then related to the mean flow velocity of the two flows. We apply the method to two quite different systems. First, a simple generic fluid model, dissipative particle dynamics, for which accurate values of the viscosity are needed to characterize the model fluid. Second, the more realistic Lennard-Jones fluid. In both cases the values we calculated are consistent with previous work but, for a given simulation time, they are more accurate than those obtained with other methods.
Nanoimprinted strain-controlled elastomeric gratings for optical wavelength tuning
Authors: Tung Yi-Chung , Kurabayashi Katsuo
Published: April 2005

We demonstrate strain-controlled gratings made of an organic elastomer, polydimethylsiloxane (PDMS), which can achieve optical wavelength tuning by varying their spatial periods. The whole device structure presented in this work incorporates a nanoimprinted PDMS grating integrated with electrostatic microelectromechanical systems actuators on a silicon chip. The fabrication of the device combines polymer soft lithography, nanoimprint lithography, and silicon micromachining across multiscale dimensions ranging from a few hundred nanometers to a few millimeters. The fine tuning capability with fast dynamic response of our PDMS/silicon hybrid optical grating device makes it attractive for use in various micro-optical instruments.
A second generation of annual pasture legumes and their potential for inclusion in Mediterranean-type farming systems
Authors: Loi A. , Howieson J. G. , Nutt B. J. , Carr S. J.
Published: April 2005

A second generation of annual pasture legumes and their root-nodule bacteria has been released to agriculture in Mediterranean-type environments. These new species emanate from selection activity focussed upon ‘alternative legumes’. In 1992, in response to changing constraints upon production, a program was initiated which sought species with different ideotypic traits to the traditional annual medics and clovers used in agriculture in southern Australia. Traits sought in the new species were deeper root systems, improved persistence from higher hardseed levels, acid tolerant symbioses, tolerance to pests and diseases and ease of harvesting with conventional cereal harvesters. Several cultivars of species new to Australian agriculture such as biserrula (Biserrula pelecinus), French serradella (Ornithopus sativus), gland clover (Trifolium glanduliferum) and improved varieties of arrowleaf clover (Trifolium vesiculosum) and yellow serradella (Ornithopus compressus) were developed and have had rapid adoption and impact in southern Australian ley- and phase-farming systems. This paper reviews the importance of ley farming for Australian agriculture, the shortcomings of the traditional medics and clovers and the imperatives for a second generation of annual pasture legume species to be developed. In addition to enhancing ley farming, the commercial availability of a second generation of annual pasture legume species has provided a much needed impetus for the development of more flexible and sustainable farming systems.
Root and root hair mechanisms that confer symbiotic competence for nodulation in acidic soils within Medicago species: a holistic model
Authors: Cheng Y. , Waktin E. L. J. , Howieson J. G. , O'Hara G. W.
Published: April 2005

Three experiments were undertaken to investigate the mechanisms used by the annual medic species, Medicago murex (Murex medic) to achieve nodulation more rapidly in acidic soils than the perennial species Medicago sativa (lucerne). In experiment 1, numbers and locations of root hairs on the primary roots of medic and lucerne were determined from plants grown in soil of pH 4.3 and 7.0. Experiment 2 enumerated the numbers of Sinorhizobium medicae (rhizobia) associated with the roots of medic and lucerne when grown in an acidic soil. Experiment 3 used a GFP-marked strain of rhizobia to determine the localised distribution of rhizobia along various zones of the primary roots of medic and lucerne in soil of pH 4.3 and 7.0. When grown in an acidic soil, medic produced 60% more root hairs/mm root along the primary root axis compared with lucerne, from 7 days after sowing. In soil of low pH, medic also had higher numbers of rhizobia associated with its entire root system than lucerne, with about 103 cfu/cm root throughout the 24-day period of the experiment, compared with lucerne for which rhizobial numbers decreased from 102 to 11 cfu/cm root over the same time period. When the intensity of fluorescence emitted by a GFP-marked transconjugant of rhizobia was measured at localised zones along the primary root of medic and lucerne grown in the acidic soil, it was 1.8-fold higher from the roots of medic than lucerne at 7 days after sowing, indicating higher numbers of rhizobia along medic roots. Hence, the numbers of rhizobia associated with the entire root system, and those colonised on localised zones of the primary root of medic were both higher than that of lucerne. These fundamental differences between the 2 species, combined with the earlier finding that lucerne tends to acidify its rhizosphere more than medic, allowed us to construct conceptual models that attempt to explain the increased symbiotic competency of medic compared with lucerne, and the different nodulation responses between medic and lucerne at low pH.
Dynamics of extracellular enzymatic activities in a shallow Mediterranean ecosystem (Tindari ponds, Sicily)
Authors: Caruso G. , Monticelli L. , Azzaro F. , Azzaro M. , Decembrini F. , La Ferla R. , Leonardi M. , Zaccone R.
Published: April 2005

Three microbial extracellular enzymes, leucine aminopeptidase (LAP), β-glucosidase (β-glu) and alkaline phosphatase (AP), were studied in six small Mediterranean littoral ponds, to evaluate the diversity of microbial activities relative to prevailing environmental conditions. The marked diversification of the trophic states, ranging from oligotrophy to eutrophy, in the ponds was reflected in a range of enzyme patterns at different spatial and temporal scales. There were higher levels and greater variability of microbial activity in the oldest and most ‘confined’ ponds (ranges: 0.55–4360.00 nm h−1, 0.15–76.44 nm h−1, 1.29–1600.00 nm h−1 for LAP, β-glu and AP respectively) compared with the youngest and most seaward ponds (ranges: 22.64–612.0 nm h−1, 0.06–48.89 nm h−1, 0.32–744.0 nm h−1 for LAP, β-glu and AP respectively). The close relationship of the degradative potential with chlorophyll-a and particulate organic carbon could be a consequence of the stimulating effect of phytoplankton-released polymeric compounds (organic matter) and/or a response of the microbial community to warm temperatures, which were recorded from July to September. Within an area less than 1 km2, different aquatic ecosystems coexist and maintain their distinctive properties in terms of microbial biogeochemical processes.
Composition and abundance of copepods and ichthyoplankton in Taiwan Strait (western North Pacific) are influenced by seasonal monsoons
Authors: Hsieh Chih-hao , Chen Chih-Shin , Chiu Tai-Sheng
Published: April 2005

Seasonal variation in hydrographic conditions in Taiwan Strait is strongly influenced by the monsoonal system. During northern winter, the China Coastal Current, pushed by the north-east (NE) monsoon, moves southwards into Taiwan Strait and during northern summer, the South China Sea Surface Current, driven by the south-west (SW) monsoon, invades the strait until the NE monsoon again prevails. As the SW monsoon wanes (in northern autumn), the Kuroshio Branch Current enters from the southern part of the strait, but stagnates in the middle because of interference by the China Coastal Current. As the NW monsoon wanes (in northern spring), the stagnation ceases and the SW monsoon begins. We characterised zooplankton (including copepods and ichthyoplankton) communities during a period when the SW monsoon was prevalent (in August), at the onset of the NE monsoon (in November) and as the NE monsoon waned (in March). Multivariate analyses of zooplankton composition and species abundances demonstrated that the structures of communities are closely related to oceanic variables (such as temperature, salinity and upwelling), which, in turn, are heavily influenced by the monsoons. The zooplankton faunas in Taiwan Strait are a mixture of local species and intruding species, the latter introduced from along the China coast during northern winter and from the South China Sea during northern summer. Our findings are fundamental to practical ecosystem management and an effective long-term monitoring programme.
Fertility aspects in yearling beef bulls grazing endophyte-infected tall fescue pastures
Authors: Schuenemann G. M. , Edwards J. L. , Hopkins F. M. , Rohrbach N. R. , Adair H. S. , Scenna F. N. , Waller J. C. , Oliver J. W. , Saxton A. M. , Schrick F. N.
Published: April 2005

During a 2-year study, yearling beef bulls were used to determine the effects of grazing on endophyte-infected tall fescue on endocrine profiles, semen quality and fertilisation potential. Bulls were allotted to graze tall fescue pastures infected with Neotyphodium coenophialum (E+; n = 20 per year) or Jesup/MaxQTM (Pennington Seed, Atlanta, GA, USA; NTE; n = 10 per year). Bulls were grouped by scrotal circumference (SC), bodyweight (BW), breed composites and age to graze tall fescue pastures from mid-November until the end of June (within each year). Blood samples, BW, SC and rectal temperatures (RT) were collected every 14 days. Semen was collected from bulls every 60 days by electroejaculation and evaluated for motility and morphology. The developmental competence of oocytes fertilised in vitro with semen from respective treatments was determined. Bulls grazing E+ pastures had decreased BW gain (P < 0.01), increased overall RT (P < 0.01) and decreased prolactin (P < 0.01) compared with animals grazing NTE pastures. Neither percentage of normal sperm morphology nor motility differed between bulls grazed on the two pasture types. Semen from E+ bulls demonstrated decreased cleavage rates (P = 0.02) compared with semen from NTE bulls. However, development of cleaved embryos to the eight-cell and blastocyst stages did not differ between the two groups. In conclusion, semen from bulls grazing E+ tall fescue resulted in decreased cleavage rates in vitro, which may lower reproductive performance owing to reduced fertilisation ability.
Contributions to a revision of Melaleuca (Myrtaceae): 4–6
Authors: Barlow BA , Cowley KJ
Published: April 2005

4. The Melaleuca cuticularis species group is revised and found to comprise 13 species, of which M. bromelioides, M. haplantha, M. sciotostyla, M. subalaris, M, teuthidoides and M. torquata are described as new. A new species, M. lecanantha, is described to accommodate that known by the illegitimate name M. conferta Bentham. Subspecies recognised include M. halmaturorum subsp. cymbifolia, based on M. cymbifolia Benth., and M. pauperifora subspp. fastigiata and mutica and M. calycina subsp. dempta which are described as new. 5. The M. lanceolata species group is revised and found to comprise five species, of which M. strobophylla and M. xerophila are described as new. Four subspecies are recognised in M. lanceolata Otto, including subspp. occidentalis, planifolia and thaeroides, all described as new. 6. The occurrence of M. quadrifaria F.Muell. in South Australia is confirmed from recent collections.
Some dematiaceous hyphomycetes from branches and phyllodes on Acacia in Australia
Authors: Sutton BC , Pascoe IG
Published: April 2005

Four dematiaceous hyphomycetes associated with grey colonies on stems and branches and 1 species associated with necrotic phyllode lesions of Acacia spp. are described and illustrated. Corynespora alternarioides on stems of A. mitchellii differs from previously described species in having muriform obpyriform conidia and non-proliferating conidiogenous cells. Corynespora queenslandica is associated with distinct lesions on phyllodes of A. leiocalyx, A. concurrens and A. aulacocarpa and again has non-proliferating conidiogenous cells but long filiform conidia. Sporidesmium corrugatescens on stems of A. dealbata combines micronematous conidiophores and distoseptate verrucose conidia. Janetia refugia on stems of A. elata has finely verruculose distoseptate conidia, the basal cell of which is darker and protuberant, and short conidiogenous cells which are more deeply pigmented towards the apices, while J. canescens on stems of A. fimbriata and A. linifolia has polyblastic conidiogenous cells and pyriform to cylindrical conidia in which the base is more darkly pigmented and the walls are distinctly invaginated at the distosepta.
A new spore cyst fungus from New Zealand
Authors: Pinnock DE , Coles RB , Donova n
Published: April 2005

Asosphaera scaccaria sp.nov. is described. The mature ascospores of A. scaccaria in spore balls as perpendicularly arranged bundles of eight, giving the mature spore ball a unique appearance. A. scaccaria is associated with the larvae and prepupae of the sand-nesting, colletid bees, Leioproctus boltoni (Cockerell), L. metallicus (Smith) and two new as yet undescribed species of Leioproctus.
Urena (Malvaveae) in Australia
Authors: Fryxell PA , Craven LA
Published: April 2005

A new Australian species of Urena, U. australiensis Fryx. & Craven, is described and illustrated. Three varieties are recognised in U. armitiana F. Muell.: var. armitiana; var. stenophylla Domain; var. spenceri (Ewart) Fryx. & Craven, stat. et comb. nov. A key to the Australian representatives of the genus is provided.
The utility of isozymes in the systematics of some Australian tree groups
Authors: Moran GF , Bell JC , Prober S
Published: April 2005

The utility of isozyme analysis in elucidating the relationship between Australian tree taxa is reviewed. Although little exploited to date, isozyme analysis is shown to be a rapid and relatively powerful method of examining relationships, if used at an appropriate taxonomic level. For Eucalyptus and Acacia, isozymes appear to be the most informative at the lower taxonomic levels. In Eucalyptus delegatensis and Casuarina cunninghamiana, isozyme data strongly support subspecies erected on the basis of morphological characteristics. In Acacia holoserocea, isozyme data predicted the existence of two subspecies, which prediction as later supported by morphological characters. An isozyme study of the phylogenetic relationships within the 'green ash' group of eucalypts yielded a phylogenetic hypothesi comparable to one derived from morphological characters, but also highlighted areas of discrepancy requiring further research. At the generic level, isozyme data for the Australian species of Litsea and Neolitsea successfully separated the two genera and allowed phylogenetic relationships within genera to be hypothesised. For the larger tree genera such as the Eucalyptus and Acacia, however, the utility of isozymes at the higher taxonomic levels is likely to be low, because of the difficulty in establishing homologies between taxa, or insufficient phylogenetic information when taxa being compared have few alleles in common.
Ribosomal RNA nucleotide sequence: a comparison of newer methods used for its determination, and its use in phylogenetic analysis
Authors: Baverstock PR , Johnson AM
Published: April 2005

Phylogenetic analysis has changed dramatically over the last few years as a result of the introduction of new molecular biological techniques. One of these, ribosomal RNA sequencing, is being used to infer higher-order relationships by laboratories around the world. In this paper we describe and then compare three methods that can be used to give at least partial sequences of ribosomal RNA, and describe how they can be used to provide data for phylogenetic analysis of taxa at different taxonomic levels.
Yulebacaulis normanii gen. et sp. nov., a new fossil tree fern from south-eastern Queensland, Australia
Authors: Tidwell WD , Rozefelds AC
Published: April 2005

Although possibly reworked, a silicified specimen consisting of outer cortex, petioles, aphlebiae and roots was collected from the Lower Cretaceous Mooga Sandstone or Tertiary sediments which lie topographically above the site near Yuleba, Queensland, and represents the new genus and species Yulebacaulis normanii. The petioles in this specimen lack stipular wings and epidermal trichomes or scales. Its clepsydroid-shaped petiolar vascular strands are oblong, straight and elongated tangential to the missing stele. Clusters of parenchyma cells at the ends of the strands form 'peripheral loops' and, at higher levels of the petioles, the 'loops' open, freeing C-shaped aphlebiae traces. Non-filiforrn aphlebiae produced by the petioles are numerous. Yulebacaulis normanii is anatomically similar to Asterochlaenopsis kirgisica (Stenzel) Sahni from the Permian of western Siberia. They differ by the peripheral loops in Y. normanii remaining open after the C-shaped traces depart, rather than staying closed as in A. kirgisica. The trace also begins as a loop in A. kirgisica and not in Y. normanii. Aphlebiae fork repeatedly in the former species and only twice in the latter. Faecal pellets produced by some small animals are present between the petioles, in the aphlebiae, and in borings in the inner and outer cortices of some petioles of Y. normanii. Based upon the size ranges of the faecal pellets, three different animals may have been involved. The pellets are loosely packed, almost filling the galleries, and appear to have been deposited by the animals as they fed upon the cortical cells. The anatomical features of Yulebacaulis are very close to some members of the Zygopteridales. If it is Early Cretaceous in age, then by assigning this genus to this group the age of this order would be extended from Upper Palaeozoic into the mid-Mesozoic.