bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular targets of elevated [CO2] in leaves and stems of Populus deltoides: implications for future tree growth and carbon sequestration
Authors: Druart Nathalie , Rodríguez-Buey Marisa , Barron-Gafford Greg , Sjödin Andreas , Bhalerao Rishikesh , Hurry Vaughan
Published: February 2006

We report the first comprehensive analysis of the effects of elevated [CO2] on gene expression in source leaf and stem sink tissues in woody plants. We have taken advantage of coppiced Populus deltoides (Bartr.) stands grown for 3 years under three different and constant elevated [CO2] in the agriforest mesocosms of Biosphere 2. Leaf area per tree was doubled by elevated [CO2] but although growth at 800 v. 400 µmol mol–1 CO2 resulted in a significant increase in stem biomass, growth was not stimulated at 1200 µmol mol–1 CO2. Growth under elevated [CO2] also resulted in significant increases in stem wood density. Analysis of expression data for the 13 490 clones present on POP1 microarrays revealed 95 and 277 [CO2]-responsive clones in leaves and stems respectively, with the response being stronger at 1200 µmol mol–1. When these [CO2]-responsive genes were assigned to functional categories, metabolism-related genes were the most responsive to elevated [CO2]. However within this category, expression of genes relating to bioenergetic processes was unchanged in leaves whereas the expression of genes for storage proteins and of those involved in control of wall expansion was enhanced. In contrast to leaves, the genes up-regulated in stems under elevated [CO2] were primarily enzymes responsible for lignin formation and polymerisation or ethylene response factors, also known to induce lignin biosynthesis. Concomitant with this enhancement of lignin biosynthesis in stems, there was a pronounced repression of genes related to cell wall formation and cell growth. These changes in gene expression have clear consequences for long-term carbon sequestration, reducing the carbon-fertilisation effect, and the potential for increased lignification may negatively impact on future wood quality for timber and paper production.
Over-expression of the rice OsAMT1-1 gene increases ammonium uptake and content, but impairs growth and development of plants under high ammonium nutrition
Authors: Hoque Mohammad S. , Masle Josette , Udvardi Michael K. , Ryan Peter R. , Upadhyaya Narayana M.
Published: February 2006

A transgenic approach was undertaken to investigate the role of a rice ammonium transporter (OsAMT1-1) in ammonium uptake and consequent ammonium assimilation under different nitrogen regimes. Transgenic lines overexpressing OsAMT1-1 were produced by Agrobacterium-mediated transformation of two rice cultivars, Taipei 309 and Jarrah, with an OsAMT1-1 cDNA gene construct driven by the maize ubiquitin promoter. Transcript levels of OsAMT1-1 in both Taipei 309 and Jarrah transgenic lines correlated positively with transgene copy number. Shoot and root biomass of some transgenic lines decreased during seedling and early vegetative stage compared to the wild type, especially when grown under high (2 mm) ammonium nutrition. Transgenic plants, particularly those of cv. Jarrah recovered in the mid-vegetative stage under high ammonium nutrition. Roots of the transgenic plants showed increased ammonium uptake and ammonium content. We conclude that the decreased biomass of the transgenic lines at early stages of growth might be caused by the accumulation of ammonium in the roots owing to the inability of ammonium assimilation to match the greater ammonium uptake.
A second member of the Nicotiana glauca lipid transfer protein gene family, NgLTP2, encodes a divergent and differentially expressed protein
Authors: Cameron Kimberly D. , Moskal William A. , Smart Lawrence B.
Published: February 2006

Multiple, highly similar members of the lipid transfer protein (LTP) family have been identified in Nicotiana glauca L. Here we describe four new members of the NgLTP gene family and further characterise one member. Three genes were isolated from a guard cell cDNA library and one (NgLTP2) was isolated from a genomic library. These four NgLTPs, as well as one described previously, NgLTP1, share >83% amino acid similarity, but the deduced protein sequence of NgLTP2 lacks the last five residues compared with other LTPs. Since the DNA sequences of the five genes are nearly identical, techniques based on nucleic acid hybridisation or PCR amplification were not sufficient to resolve the expression of the individual genes with confidence. Therefore, we characterised the expression pattern of NgLTP2, the only NgLTP gene that was not found in the guard cell cDNA library, using an NgLTP2 promoter–GUS reporter assay. GUS activity driven by the NgLTP2 promoter was assayed in three species of transgenic plants as an indicator of the endogenous pattern of expression of this gene. GUS was strongly induced upon wounding, whereas NgLTP1 was induced by drought stress. Sequence analysis of the NgLTP2 promoter revealed cis-acting motifs associated with induction by wounding. Differential expression of the NgLTP gene family, revealed by the different expression patterns of NgLTP1 and NgLTP2, is further evidence that these genes have multiple functions in N. glauca.
Agrobacterium-mediated transformation of dormant lateral buds in poplar trees reveals developmental patterns in secondary stem tissues
Authors: Spokevicius Antanas V. , Van Beveren Kim S. , Bossinger Gerd
Published: February 2006

In an attempt to devise a method for the rapid creation of somatic transgenic wood sectors of sufficient size that would allow us to detect and analyse altered wood characteristics within them, we have explored the manual wounding and subsequent infection with Agrobacterium of dormant lateral buds in poplar. Following treatment and transformation with a 35S–GUS construct, frequent stable transformation was found in the form of distinct and specific GUS staining patterns in the outer cortex, cambial region (including primary and secondary xylem and phloem) and pith. Sector frequency and size were consistent with anatomical features of dormant lateral buds at the time of manual wounding and Agrobacterium-infection. The suitability of somatic sector analysis for functional genomic studies as well as for studies investigating pattern formation and the developmental fate of various cell-types within poplar stems is discussed.
Cell wall disassembly in ripening fruit
Authors: Brummell David A.
Published: February 2006

Fruit softening during ripening involves a coordinated series of modifications to the polysaccharide components of the primary cell wall and middle lamella, resulting in a weakening of the structure. Degradation of polysaccharides and alterations in the bonding between polymers cause an increase in cell separation and a softening and swelling of the wall, which, combined with alterations in turgor, bring about fruit softening and textural changes. A wide range in the extent of cell wall pectic modifications has been observed between species, whereas the depolymerisation of xyloglucan is relatively limited and more consistent. The earliest events to be initiated are usually a loss of pectic galactan side chains and the depolymerisation of matrix glycans, which may begin before ripening, followed by a loss of pectic arabinan side chains and pectin solubilisation. The depolymerisation of pectins may begin during early to mid-ripening, but is usually most pronounced late in ripening. However, some of these events may be absent or occur at very low levels in some species. Cell wall swelling may be related to a loosening of the xyloglucan–cellulose network and to pectin solubilisation, and these processes combined with the loss of pectic side chains increase wall porosity. An increase in wall porosity later in ripening may allow increased access of degradative enzymes to their substrates.
Drusen complement components C3a and C5a promote choroidal neovascularization
Authors: Nozaki Miho , Raisler Brian J. , Sakurai Eiji , Sarma J. Vidya , Barnum Scott R. , Lambris John D. , Chen Yali , Zhang Kang , Ambati Balamurali K. , Baffi Judit Z. , Ambati Jayakrishna
Published: February 2006

Age-related macular degeneration (AMD) is the leading cause of irreversible blindness in industrialized nations, affecting 30–50 million people worldwide. The earliest clinical hallmark of AMD is the presence of drusen, extracellular deposits that accumulate beneath the retinal pigmented epithelium. Although drusen nearly always precede and increase the risk of choroidal neovascularization (CNV), the late vision-threatening stage of AMD, it is unknown whether drusen contribute to the development of CNV. Both in patients with AMD and in a recently described mouse model of AMD, early subretinal pigmented epithelium deposition of complement components C3 and C5 occurs, suggesting a contributing role for these inflammatory proteins in the development of AMD. Here we provide evidence that bioactive fragments of these complement components (C3a and C5a) are present in drusen of patients with AMD, and that C3a and C5a induce VEGF expressionin vitroandin vivo. Further, we demonstrate that C3a and C5a are generated early in the course of laser-induced CNV, an accelerated model of neovascular AMD driven by VEGF and recruitment of leukocytes into the choroid. We also show that genetic ablation of receptors for C3a or C5a reduces VEGF expression, leukocyte recruitment, and CNV formation after laser injury, and that antibody-mediated neutralization of C3a or C5a or pharmacological blockade of their receptors also reduces CNV. Collectively, these findings establish a mechanistic basis for the clinical observation that drusen predispose to CNV, revealing a role for immunological phenomena in angiogenesis and providing therapeutic targets for AMD.
Cohn’s
Crenothrix
is a filamentous methane oxidizer with an unusual methane monooxygenase
Authors: Stoecker Kilian , Bendinger Bernd , Schöning Björn , Nielsen Per H. , Nielsen Jeppe L. , Baranyi Christian , Toenshoff Elena R. , Daims Holger , Wagner Michael
Published: February 2006

135 years ago Ferdinand Cohn, the founder of bacteriology, microscopically observed a conspicuous filamentous bacterium with a complex life cycle and described it as
Crenothrix polyspora
. This uncultured bacterium is infamous for mass developments in drinking water systems, but its phylogeny and physiology remained unknown. We show that
C. polyspora
is a gammaproteobacterium closely related to methanotrophs and capable of oxidizing methane. We discovered that
C. polyspora
encodes a phylogenetically very unusual particulate methane monooxygenase whose expression is strongly increased in the presence of methane. Our findings demonstrate a previously unrecognized complexity of the evolutionary history and cell biology of methane-oxidizing bacteria.
Arsenic detoxification and evolution of trimethylarsine gas by a microbial arsenite
S
-adenosylmethionine methyltransferase
Authors: Qin Jie , Rosen Barry P. , Zhang Yang , Wang Gejiao , Franke Sylvia , Rensing Christopher
Published: February 2006

In this article, a mechanism of arsenite [As(III)]resistance through methylation and subsequent volatization is described. Heterologous expression of
arsM
from
Rhodopseudomonas palustris
was shown to confer As(III) resistance to an arsenic-sensitive strain of
Escherichia coli
. ArsM catalyzes the formation of a number of methylated intermediates from As(III), with trimethylarsine as the end product. The net result is loss of arsenic, from both the medium and the cells. Because ArsM homologues are widespread in nature, this microbial-mediated transformation is proposed to have an important impact on the global arsenic cycle.
RETRACTED: Crystal structure of human apolipoprotein A-I: Insights into its protective effect against cardiovascular diseases
Authors: Ajees A. Abdul , Anantharamaiah G. M. , Mishra Vinod K. , Hussain M. Mahmood , Murthy H. M. Krishna
Published: February 2006

Despite three decades of extensive studies on human apolipoprotein A-I (apoA-I), the major protein component in high-density lipoproteins, the molecular basis for its antiatherogenic function is elusive, in part because of lack of a structure of the full-length protein. We describe here the crystal structure of lipid-free apoA-I at 2.4 Å. The structure shows that apoA-I is comprised of an N-terminal four-helix bundle and two C-terminal helices. The N-terminal domain plays a prominent role in maintaining its lipid-free conformation, indicating that mutants with truncations in this region form inadequate models for explaining functional properties of apoA-I. A model for transformation of the lipid-free conformation to the high-density lipoprotein-bound form follows from an analysis of solvent-accessible hydrophobic patches on the surface of the structure and their proximity to the hydrophobic core of the four-helix bundle. The crystal structure of human apoA-I displays a hitherto-unobserved array of positively and negatively charged areas on the surface. Positioning of the charged surface patches relative to hydrophobic regions near the C terminus of the protein offers insights into its interaction with cell-surface components of the reverse cholesterol transport pathway and antiatherogenic properties of this protein. This structure provides a much-needed structural template for exploration of molecular mechanisms by which human apoA-I ameliorates atherosclerosis and inflammatory diseases.
Roles of static and dynamic domains in stability and catalysis of adenylate kinase
Authors: Bae Euiyoung , Phillips George N.
Published: February 2006

Protein dynamics, including conformational switching, are recognized to be crucial for the function of many systems. These motions are more challenging to study than simple static structures. Here, we present evidence suggesting that in the enzyme adenylate kinase large “hinge bending” motions closely related to catalysis are regulated by intrinsic properties of the moving domains and not by their hinges, by anchoring domains, or by remote allosteric-like regions. From a pair of highly homologous mesophilic and thermophilic adenylate kinases, we generated a series of chimeric enzymes using a previously undescribed method with synthetic genes. Subsequent analysis of the chimeras has revealed unexpected spatial separation of stability and activity control. Our results highlight specific contributions of dynamics to catalysis in adenylate kinase. Furthermore, the overall strategy and the specific mutagenesis method used in this study can be generally applied.
Nonsynchronous recovery of community characteristics in island spiders after a catastrophic hurricane
Authors: Schoener Thomas W. , Spiller David A.
Published: February 2006

We monitored spiders on 41 Bahamian islands for 4 years before and then 4 years after the catastrophic Hurricane Floyd passed directly over the site, inundating the study islands with its storm surge. The respective recoveries of major community properties after this annihilation were far from synchronous. Before the hurricane, the species-area relation was generally strong and the slope showed no temporal trend. After the hurricane, the slope increased from near zero (7 months later) to a value about equal to its prehurricane state. The lizard effect (difference in spider abundance or species richness between islands with and without the lizard
Anolis sagrei
) was generally strong before the hurricane; 7 months after, the lizard effect on abundance was weak and the effect on richness had vanished. In subsequent years, the lizard effect on abundance became strong again, but the effect on species richness remained weak. The strength of the lizard effect on both abundance and richness over the 8 years was strongly positively related to the density of lizards measured on a subset of the study islands. Twelve months after the hurricane, species richness averaged over all islands rebounded to the last prehurricane value, but abundance attained only about half that value; this finding was remarkably similar to results found in an earlier study of spiders impacted by Hurricane Lili (1996) in a different Bahamian region. Nonetheless, in the next 3 years, species richness failed to increase further, part of its long-term decline at the study site.
Monitoring bacterial chemotaxis by using bioluminescence resonance energy transfer: Absence of feedback from the flagellar motors
Authors: Shimizu Thomas S. , Delalez Nicolas , Pichler Klemens , Berg Howard C.
Published: February 2006

We looked for a feedback system in
Escherichia coli
that might sense the rotational bias of flagellar motors and regulate the activity of the chemotaxis receptor kinase. Our search was based on the assumption that any machinery that senses rotational bias will be perturbed if flagellar rotation stops. We monitored the activity of the kinase in swimming cells by bioluminescence resonance energy transfer (BRET) between
Renilla
luciferase fused to the phosphatase, CheZ, and yellow fluorescent protein fused to the response regulator, CheY. Then we jammed the flagellar motors by adding an antifilament antibody that crosslinks adjacent filaments in flagellar bundles. At steady state, the rate of phosphorylation of CheY is equal to the rate of dephosphorylation of CheY-P, which is proportional to the degree of association between CheZ and CheY-P, the quantity sensed by BRET. No changes were observed, even upon addition of an amount of antibody that stopped the swimming of >95% of cells within a few seconds. So, the kinase does not appear to be sensitive to motor output. The BRET technique is complementary to one based on FRET, described previously. Its reliability was confirmed by measurements of the response of cells to the addition of attractants.
Paracrine signaling through the epithelial estrogen receptor α is required for proliferation and morphogenesis in the mammary gland
Authors: Mallepell Sonia , Krust Andrée , Chambon Pierre , Brisken Cathrin
Published: February 2006

Estradiol is a major regulator of postnatal mammary gland development and thought to exert its effects through estrogen receptor α (ERα) expressed in the mammary gland stroma and epithelium. Previous studies, however, were confounded by the use of an ERα mutant strain that retains some of the protein with transactivation activity. Here, we use an ERα
−/−
mouse strain in which no ERα transcript can be detected to analyze mammary gland development in the complete absence of ERα signaling. The ERα
−/−
females show no development beyond a rudimentary ductal system. By grafting ERα
−/−
epithelium or stroma in combination with ERα WT stroma or epithelium, we show that the primary target for estradiol is the mammary epithelium, whereas a direct response of the mammary stroma is not required for mammary gland development to proceed normally. Mammary glands reconstituted with ERα
−/−
mammary epithelium exposed to pregnancy hormones show increased transcription of milk protein genes, indicating that ERα signaling is not an absolute requirement for a transcriptional response to pregnancy hormones. When ERα
−/−
mammary epithelial cells are in close vicinity to ERα WT cells, they proliferate and contribute to all aspects of mammary gland development, indicating that estradiol, like progesterone, orchestrates proliferation and morphogenesis by a paracrine mechanism, affecting nearby cells in the mammary epithelium.
The effects of fish oil supplementation on rumen metabolism and the biohydrogenation of unsaturated fatty acids in beef steers given diets containing sunflower oil
Authors: Lee M. R. F. , Tweed J. K. S. , Moloney A. P. , Scollan N. D.
Published: February 2006

Duodenally and ruminally fistulated steers were offered grass silage and one of three concentrates at a ratio of 60: 40 (forage: concentrate on a dry-matter basis) : F0, F1 or F4 at 14 g/kg live weight. The concentrates were designed to be iso-lipid and to provide the same amount of sunflower oil but increasing amounts of fish oil : 0, 1 and 4 g per 100 g, respectively. Ruminal characteristics were measured along with fatty acid intakes and duodenal flows to determine the effect of fish oil on : ruminal pH, ammonia-N concentration, volatile fatty acid (VFA) concentration and polyunsaturated fatty acid (PUFA) metabolism. Fish oil had no significant effect on ruminal pH, ammonia-N concentration or the molar proportions of the major VFA, although total VFA concentration was significantly reduced at the highest level of fish oil inclusion. Fish oil significantly increased the flow of long chain PUFA, total conjugated linoleic acid and vaccenic acid to the duodenum and decreased the flow of stearic acid. Biohydrogenation, as determined by the net loss of fatty acid between the mouth and duodenum, of oleic and linolenic acid was not affected by fish oil inclusion and averaged 0·64 and 0·92, respectively. There was a small increase in the biohydrogenation of linoleic acid with increasing fish oil from 0·89 to 0·92 (P< 0·01) on F0 and F4, respectively. Biohydrogenation of the long chain PUFA C20 : 5(n-3) and C22 : 6(n-3) increased from 0·49 and 0·74 to 0·79 and 0·86 (P< 0·01), respectively when fish oil in the concentrate increased from 1 to 4 g per 100 g. The net effect of fish oil on lipid metabolism appears to inhibit the transition of vaccenic acid to stearic acid in the rumen resulting in a build up of this intermediate in the biohydrogenation pathway of C18 PUFA.
Tissue expression of uncoupling proteins in piglets given a low protein diet: a rôle for UCP2 and UCP3 in diet-induced thermogenesis
Authors: Jia J. , Jois M. , McDowell G. H.
Published: February 2006

The purpose of the study was to investigate the rôle of novel mitochondrial uncoupling proteins UCP2 and UCP3 in the poor efficiency of energy utilization observed in piglets offered a low protein diet. Eight male piglets (Landrace × Large White) from different litters were allocated randomly to one of two groups; a high protein group (HP) was given restricted amounts of a diet containing 270 g/kg of crude protein whereas the low protein group (LP) was offered ad libitum a diet containing 27 g/kg of crude protein. The experimental period extended over 4 weeks, including an initial period of 1 week for adaptation. Live weights were recorded weekly and food residues were weighed daily. During the 2nd and 3rd weeks, faeces were collected for measurement of digestible energy intake. Over the last 2 weeks whole body oxygen consumption was measured by indirect calorimetry before, 1·5 h after and 3·5 h after the start of feeding. The piglets were killed at the end of week 4 and tissue expressions of UCP2 and UCP3 were measured by Northern blot analyses using a partial length pig UCP2 probe that had high homology to both UCP2 and UCP3. The HP group maintained their live weight during the experimental period whereas the live weight of the LP group increased significantly (P < 0·01) but only slightly despite a digestible energy intake that was more than twice that of the HP group (P < 0·01). Whole body oxygen consumption of the LP piglets was about three times that of the HP piglets (P < 0·05), with similar increases 1·5 h after feeding (P < 0·05) in both groups indicating increased thermogenesis. A marked increase in the expression of UCP2 and UCP3 was observed in the skeletal muscle, adipose tissue and spleen of the LP piglets. The results are consistent with a rôle for UCP2 and UCP3 in diet-induced thermogenesis in piglets and specifically in the regulation of efficiency of energy utilization in pigs.
A new model for low‐dose food challenge in children with allergy to milk or egg
Authors: Devenney Irene , Norrman Gunilla , Oldaeus Göran , Strömberg Leif , Fälth‐Magnusson Karin
Published: February 2006

Background: Atopic eczema and food allergy are common in early childhood. Children seem to gradually develop tolerance to milk and egg, and it is a relief for families when their child can tolerate small amounts of these basic foods, even if larger doses may still cause symptoms. Aim: To develop a model for low‐dose oral food challenge, facilitating re‐/introduction of milk or egg. Methods: In 39 children sensitized to milk and/or egg, we performed 52 challenges using a new standardized model for low‐dose oral food challenge. The recipes were validated for blinding with sensorial tests. Results: Four children challenged to milk had a positive challenge outcome. There were no significant differences with respect to family history, associated atopic manifestations, nutritional supply, eczema severity, or skin‐prick test compared with the non‐reacting children, but total and specific IgE values were significantly higher. All but two of the non‐reacting children were able to introduce milk and egg into their diet without problems.

Conclusion: We report recipes and a protocol to be used for standardized open and double‐blind placebo‐controlled low‐dose food challenge in young children, enabling the introduction of small amounts of egg and milk into the diet during tolerance development.
Is paediatric assessment of motor development of very preterm and low‐birthweight children appropriate?
Authors: DE Kleine Martin J. K. , Van Der Sanden Maria W. G. Nijhuis , Den Ouden A. Lya
Published: February 2006

Aim: To determine whether paediatricians that examine, in regular clinical practice, very preterm and very‐low‐birthweight children at 5 y of age detect neurological impairments and functional motor problems in these children. Methods: We compared a paediatric judgement, a standardized neurological examination (Touwen examination) and a screening of motor development (Denver Developmental Screening Test; DDST) with the Movement ABC in 396 5‐y‐old very preterm and low‐birthweight children. Results: The Movement ABC detected clinically important motor disorders in 20.5% and borderline disturbances in 22.5% of the children. Compared to the Movement ABC, the sensitivity of the paediatric judgement was 0.19, Touwen examination 0.62 and DDST 0.52; the negative predictive values were 0.61, 0.74 and 0.69, respectively.

Conclusion: Paediatric assessment of motor development in 5‐y‐old very preterm and low‐birthweight children generally is not sensitive enough to detect functional motor problems. The Movement ABC should be added to the assessment of the motor development of very preterm and low‐birthweight children at 5 y of age.
End‐tidal carbon monoxide measurements in infant respiratory distress syndrome
Authors: Krediet Tannette G. , Cirkel Geert A. , Vreman Hendrik J. , Wong Ronald J. , Stevenson David K. , Groenendaal Floris , Egberts Johannes , Van Bel Frank
Published: February 2006

Background: RDS involving inflammatory and oxidative processes may lead to increased production of carbon monoxide (CO). Aim: The relationship between end‐tidal CO, corrected for inhaled CO (ETCOc), and RDS severity was investigated in preterm infants as well as the value of early ETCOc measurements to predict chronic lung disease. Methods: 78 infants (30 no RDS, 32 moderate RDS, 16 severe RDS) were included. ETCOc was measured using the CO‐Stat™ End Tidal Breath Analyzer. Results: ETCOc was significantly higher in RDS compared to no RDS during the first week (p<0.05). Severity of RDS was the most significant independent variable in a stepwise regression model related to ETCOc (F‐test: 18.17). Negative predictive value of early (within first 12 h of life) ETCOc measurement (<2.5 ppm) for development of chronic lung disease was excellent (100%).

Conclusion: During severe RDS, inflammation may contribute to increased lipid peroxidation leading to increased local CO production in the lung, indicated by increased ETCOc. Early ETCOc determinations may be helpful to exclude occurrence of chronic lung disease.
Role of Heme Oxygenase in the Protection Afforded Skeletal Muscle During Ischemic Tolerance
Authors: DUNGEY ALISON A. , BADHWAR AMIT , BIHARI AURELIA , KVIETYS PETER R. , HARRIS KENNETH A. , FORBES THOMAS L. , POTTER RICHARD F.
Published: February 2006

Objective:Ischemic tolerance (IT) is known to improve resistance to ischemia/reperfusion (I/R)‐induced injury; however, the mechanisms remain unknown. The authors hypothesized that induction of heme oxygenase (HO), a heat shock protein, would provide anti‐inflammatory benefits during IT, thereby preventing leukocyte‐derived I/R injury.

Methods:Male Wistar rats were randomly assigned to sham (n= 4), I/R (n= 9), preconditioning (PC)+I/R (n= 7), chromium mesoporphyrrin, to inhibit HO (CrMP;n= 4), or PC+I/R+CrMP (n= 6) groups. PC consisted of 5 cycles of I/R, each lasting 10 min, induced by tightening a tourniquet placed above the greater trochantor of the hindlimb. Twenty‐four hours later, the hindlimb underwent 2 h of no‐flow ischemia followed by intravital microscopy during 90 min reperfusion to assess capillary perfusion (#/mm), tissue injury (ratio of ethidium bromide to bisbenzimide labeled cells/100 μ m2), leukocyte rolling (Lr, #/1000 μ m2), and adhesion (La, #/1000 μ m2) in postcapillary venules of the extensor digitorum longus (EDL) muscle.Results:In the I/R group, Lr was significantly increased (7.1 ± 0.4) compared to sham (3.1 ± 0.4). PC+I/R increased Lr (10.8 ± 0.72), which was further exacerbated by the removal of HO (14.2 ± 1.3). La (7.8 ± 2.0) was significantly increased compared to sham (2.4 ± 0.9), while PC returned La back to sham levels (1.9 ± 0.7). Removal of HO activity, via CrMP, had no significant effect on La (3.9 ± 0.7). However, CrMP removed the protection to microvascular perfusion (I/R = 9.4 ± 1.1, PC = 16.6 ± 1.8, sham = 20.5 ± 2.8, PC+CrMP+I/R = 12.3 ± 2.3) and prevented protection from ischemia‐induced tissue injury.

Conclusion:The data suggest that HO is an important protective mechanism during IT in skeletal muscle, but such protection was by mechanisms other than altered leukocyte–endothelial cell interaction.
Role of Vascular Heme Oxygenase in Reduced Myogenic Reactivity Following Chronic Hypoxia
Authors: NAIK JAY S. , WALKER BENJIMEN R.
Published: February 2006

Objective:Exposure to chronic hypoxia (CH) results in a persistent endothelium‐dependent vascular smooth muscle hyperpolarization that diminishes vasoconstrictor reactivity. Experiments were performed to test the hypothesis that products of both cytochrome P450 epoxygenase (CYP) and heme oxygenase (HO) are required for the persistent diminished myogenic reactivity following CH.

Methods:The authors examined myogenic responses of mesenteric arteries isolated from control and CH (48 h; PB= 380 mmHg) rats in the presence of a HO inhibitor (zinc protoporphyrin IX; ZnPPIX) or combined HO and CYP epoxygenase inhibition (sulfaphenazole). Arteries were isolated and cannulated and the vascular smooth muscle was loaded with the Ca2 +indicator Fura‐2.

Results:Control vessels maintained their internal diameter in response to step increases in intraluminal pressure, whereas arteries from CH animals passively distended. ZnPPIX augmented myogenic reactivity and [Ca2 +] in arteries from CH animals. Combined administration of sulfaphenazole and ZnPPIX did not have an additional effect compared to ZnPPIX alone. Myogenic reactivity in control vessels was not altered by ZnPPIX or ZnPPIX + sulfaphenazole.

Conclusions:HO appears to play a role in regulating myogenic reactivity following CH. Furthermore, these data suggest that products of HO and CYP are both required for the observed attenuation in vasoreactivity following CH.
Platelet Recruitment in the Murine Hepatic Microvasculature During Experimental Sepsis: Role of Neutrophils
Authors: SINGER GEORG , URAKAMI HIDEJIRO , SPECIAN ROBERT D. , STOKES KAREN Y. , GRANGER D. NEIL
Published: February 2006

Objectives: Sepsis is a major clinical problem that often results in the dysfunction or failure of multiple organs, including the liver. While inflammatory cell activation has been implicated as an early critical event in sepsis‐induced liver dysfunction, there is growing evidence for the involvement of activated platelets in this pathologic process.

Methods: Intravital microscopy was used in this study to assess the magnitude and time course of platelet adhesion in the liver microcirculation during experimental sepsis and to determine whether the platelet accumulation is linked to leukocyte infiltration. The adhesion of platelets and leukocytes in terminal hepatic venules (THV) and sinusoids was quantified at 2, 4, and 6 h after abdominal sepsis induced by cecal ligation and puncture (CLP).

Results: While the rolling and firm adhesion of platelets and leukocytes in THV were not altered in the first 2 h after CLP, platelet recruitment was observed at 4 h and further elevated at 6 h after CLP. Leukocyte adhesion in THV exhibited a similar time course. A similar accumulation of blood cells in sinusoids was noted after CLP. This was accompanied by an increased number of nonperfused sinusoids. CLP‐induced leukocyte and platelet recruitment in THV and sinusoids was attenuated in mice rendered neutropenic with anti‐neutrophil serum.

Conclusion: These findings indicate that sepsis is associated with a neutrophil‐dependent recruitment of platelets in the liver microcirculation that impairs sinusoidal perfusion and may contribute to the liver dysfunction associated with sepsis.
Induction of LFA‐1‐Dependent Neutrophil Rolling on ICAM‐1 by Engagement of E‐Selectin
Authors: CHESNUTT BETSY C. , SMITH DAVID F. , RAFFLER NIKOLAI A. , SMITH MICHAEL L. , WHITE E. J. , LEY KLAUS
Published: February 2006

Objective: To study rolling of mouse neutrophils on E‐selectin and ICAM‐1 in an ex vivo flow chamber system.

Methods: The authors developed a small autoperfused flow chamber (20 × 200‐μ m cross section) that allows direct visualization of cells with and without fluorescent labeling and does not require recirculation of blood.

Results: Neutrophils rolled on E‐selectin alone, but were unable to interact with immobilized ICAM‐1. When ICAM‐1 was co‐immobilized with E‐selectin, the number of cells that rolled was doubled, but no significant firm adhesion was observed. This phenomenon was specific for E‐selectin, and no enhancement of rolling was observed when P‐selectin was immobilized with ICAM‐1. The increased neutrophil rolling seen on E‐selectin and ICAM‐1 substrates required β2 integrins. Treating mice with antibodies to the β2 integrins LFA‐1 and Mac‐1 showed that LFA‐1 was primarily responsible for mediating rolling on ICAM‐1 in this model. Increased rolling on E‐selectin and ICAM‐1 was significantly reduced following administration of a specific p38 mitogen‐activated protein kinase (MAPK) inhibitor.

Conclusion: The data show that neutrophil rolling on E‐selectin leads to partial activation of LFA‐1, enabling LFA‐1‐dependent rolling on ICAM‐1. This mechanism is likely to amplify and accelerate neutrophil recruitment in inflammation.
A Practical Extension of Hydrodynamic Theory of Porous Transport for Hydrophilic Solutes
Authors: BASSINGTHWAIGHTE JAMES B.
Published: February 2006

Objective: The equations for transport of hydrophilic solutes through aqueous pores provide a fundamental basis for examining capillary–tissue exchange and water and solute flux through transmembrane channels, but the theory remains incomplete for ratios, α, of sphere diameters to pore diameters greater than 0.4. Values for permeabilities, P, and reflection coefficients, σ, from Lewellen [18], working with Lightfoot et al. [19], at α = 0.5 and 0.95, were combined with earlier values for α < 0.4, and the physically required values at α = 1.0, to provide accurate expressions over the whole range of 0 < α < 1.

Methods: The “data” were the long‐accepted theory for α < 0.2 and the computational results from Lewellen and Lightfoot et al. on hard spheres (of 5 different α's) moving by convection and diffusion through a tight cylindrical pore, accounting for molecular exclusion, viscous forces, pressure drop, torque and rotation of spheres off the center line (averaging across all accessible radial positions), and the asymptotic values at α = 1.0. Coefficients for frictional hindrance to diffusion, F(α), and drag, G(α), and functions for σ (α) and P(α), were represented by power law functions and the parameters optimized to give best fits to the combined “data.”

Results: The reflection coefficients = {1 − [1 − (1 − φ)2]G′(α)} + 2α2fF′(α), and the relative permeability P/Pmax = φF ′(α)[1 + 9α5.5 · (1.0−α5)0.02], where φ is the partition coefficient or volume fraction of the pore available to solute. The new expression for the diffusive hindrance is F′(α) = (1−α2)3/2φ/[1+0.2 · α[p2·(1 − α2)16], and for the drag factor is G′(α) = (1−2α2/3−0.20217α5)/(1 − 0.75851α5) − 0.0431[1 − (1 − α10)]. All of these converge monotonically to the correct limits at α = 1.

Conclusions: These are the first expressions providing hydrodynamically based estimates of σ (α) and P(α) over 0 < α < 1 They should be accurate to within 1–2%.
A Role for Heterocellular Coupling and EETs in Dilation of Rat Cremaster Arteries
Authors: MCSHERRY IAIN N. , SANDOW SHAUN L. , CAMPBELL WILLIAM B. , FALCK JOHN R. , HILL MICHAEL A. , DORA KIM A.
Published: February 2006

Objective: The authors probed endothelium‐dependent dilation and endothelial cell Ca2 + handling in myogenically active resistance arteries.

Methods: First‐order arteries were removed from rat cremaster muscles, cannulated, and pressurized (75 mmHg). Vessel diameter and endothelial cell Ca2 + were monitored using confocal microscopy, and arterial ultrastructure was determined using electron microscopy.

Results: Acetylcholine (ACh) stimulated elevations and oscillations in endothelial cell Ca2 +, and concentration‐dependently dilated arteries with myogenic tone. NO‐independent dilation was blocked by 35 mM K+. Combined IKCa (1 μ M TRAM‐34) and SKCa (100 nM apamin) blockade partially inhibited NO‐independent relaxations, with residual relaxations sensitive to BKCa or cytochrome P‐450 inhibition (100 nM iberiotoxin, and 20 μ M 17‐ODYA or 10 μ M MS‐PPOH). 11,12‐EET stimulated iberiotoxin‐sensitive dilation, but did not affect endothelial cell Ca2 +. 15 mM K+ evoked dilation sensitive to inhibition of KIR (30 μ M Ba2 +) and Na+/K+‐ATPase (10 μ M ouabain), whereas these blockers did not affect ACh‐mediated dilations. Homo‐ and heterocellular gap junctions were identified in radial sections through arteries.

Conclusion:These data suggest that rises in endothelial cell Ca2 + stimulate SKCa and IKCa channels, leading to hyperpolarization and dilation, likely due to electrical coupling. In addition, a component was unmasked following SKCa and IKCa blockade, attributable to activation of BKCa channels by cytochrome P‐450 metabolites.
Disinfection of Endoscopes: Review of New Chemical Sterilants Used for High-Level Disinfection
Authors: Rutala William A. , Weber David J.
Published: February 2006

Chemical sterilants are used to high-level disinfect heat-sensitive semicritical items such as endoscopes. Most endoscopes have been reprocessed between each patient use with glutaraldehyde (>2%) or the Steris System 1. Several new chemical sterilants have been developed recently, including 7.5% hydrogen peroxide, 0.08% peracetic acid plus 1.0% hydrogen peroxide, and 0.55% orthophthalaldehyde. In order to aid the infection control professional in choosing the appropriate disinfection methodology, this article reviews the characteristics, advantages, and disadvantages of high-level disinfectants intended for reprocessing endoscopes.
Isolation of Ureaplasma urealyticum and Mycoplasma hominis From Public Toilet Bowls
Authors: Potasman Israel , Oren Amnon , Srugo Isaac
Published: February 2006

The presence ofUreaplasma urealyticum, Mycoplasma hominis, andChlamydia trachomatiswas explored in 50 public restroom toilet bowls. We used culture, antigen detection, polymerase chain reaction, and survival assay. Five bowls (10%) were contaminated with at least one organism.U urealyticumwas found in four bowls,M hominisin three, andC trachomatisin one.U urealyticumsurvived on the toilet rim for up to 2 hours.
Risk of Transmission and Features of Hepatitis C After Needlestick Injuries
Authors: Hamid Saeed S. , Farooqui Badar , Rizvi Qudsia , Sultana Tarranum , Siddiqui Anwar A.
Published: February 2006

The rate of transmission and management of needlestick injuries from hepatitis C virus (HCV) patients to healthcare workers is still a matter of debate. We used a stringent protocol using monthly transaminase levels and polymerase chain reaction for HCV RNA to monitor 53 healthcare workers prospectively for up to 6 months following needle injuries from HCV-positive patients. Evidence of transmission of HCV was found in only 2 workers (4%) with mild asymptomatic infection, one of which resolved spontaneously. Based on our experience, we now use a less-intensive follow-up protocol. Further investigation is required to determine the most cost-effective method to monitor individuals who suffer a needlestick injury from an HCV-positive patient.
Vancomycin Use in a Hospital With Vancomycin Restriction
Authors: Roghmann Mary-Claire , Perdue Beulah E. , Polish Louis
Published: February 2006

We evaluated vancomycin use in a hospital with endemic vancomycin-resistant enterococci and a vancomycin restriction program. Only 68% of vancomycin was prescribed appropriately. Inappropriate use was due primarily to empirical therapy. In the patients with a microbiological diagnosis following empirical therapy, 83% (25/30) had infections due to bacteria sensitive to an appropriate antibiotic other than vancomycin. However, only 60% (15/25) of these patients had their vancomycin orders changed.
Bacterial Filters in Anesthesia: Results of 9 Years of Surveillance
Authors: Hassel Stijn van , Laveaux Margot , Leenders Marianne , Kaan Jan A. , Mintjes Joke
Published: February 2006

In 9 years of surveillance of postoperative lower respiratory infections, the infection rate in patients following regional anesthesia was 0.2% and 0.1% in patients following general anesthesia. No bacterial filters in the breathing circuit were used. Infected patients had risk factors such as type of surgery, American Society of Anesthesiologists class ≥2, old age, chronic obstructive pulmonary disease, or smoking habits. Infections were not clustered. This suggests that, in our setting, patient factors are most important in the development of postoperative lower respiratory infections and that the role of bacterial filters as a preventive measure is negligible.
Inactivation of Respiratory Syncytial Virus by Generic Hand Dishwashing Detergents and Antibacterial Hand Soaps
Authors: Contreras Patricia A. , Sami Iman R. , Darnell Miriam E. R. , Ottolini Martin G. , Prince Gregory A.
Published: February 2006

In an in-vitro test, generic liquid hand dishwashing detergents were as much as 100-fold more effective than proprietary antibacterial soaps in inactivating respiratory syncytial virus (RSV). The use of such detergents for hand washing during annual RSV epidemics, or the incorporation of their antiviral components into antibacterial soaps might be considered to limit nosocomial spread (Infect Control Hosp Epidemiol1999;20:57-58).
An Outbreak of Salmonella typhimurium at a Teaching Hospital
Authors: McCall Bradley , McCormack Joseph G. , Stafford Russell , Towner Christopher
Published: February 2006

An outbreak of Salmonella typhimurium infection in December 1996 affected 52 patients, relatives, and staff of a large teaching hospital in southeast Queensland. Assorted sandwiches were identified as the vehicle of transmission. This article describes the outbreak investigation and demonstrates the importance of food hygiene and timely public health interventions.
Recurrent Clostridium Difficile Disease: Epidemiology and Clinical Characteristics
Authors: McFarland Lynne V. , Surawicz Christina M. , Rubin Moshe , Fekety Robert , Elmer Gary W. , Greenberg Richard N.
Published: February 2006

Objective:

To describe the epidemiology, diagnosis, risk factors, patient impact, and treatment strategies for recurrentClostridium difficile-associated disease (CDAD).

Design:

Data were collected as part of a blinded, placebo-controlled clinical trial testing a new combination treatment for recurrent CDAD. Retrospective data regarding prior CDAD episodes were collected from interviews and medical-chart review. Prospective data on the current CDAD episode, risk factors, and recurrence rates were collected during a 2-month follow-up.

Settings:

National referral study.

Participants:

Patients with recurrent CDAD.

Interventions:

Treatment with a 10-day course of low-dose (500 mg/d) or high-dose (2 g/d) vancomycin or metronidazole (1 g/d).

Results:

Recurrent CDAD was found to have a lengthy course involving multiple episodes of diarrhea, abdominal cramping, nausea, and fever. CDAD may recur over several years despite frequent treatment with antibiotics. Recurrence rates were similar regardless of the choice or dose of antibiotic. Recurrent CDAD is not a trivial disease: patients may have multiple episodes (as many as 14), may require hospitalization, and the mean lifetime cost of direct medical care was $10,970 per patient. Fortunately, the disease does not become progressively more severe as the number of episodes increase. Two risk factors predictive for recurrent CDAD were found: increasing age and a decreased quality-of-life score at enrollment.

Conclusions:

Recurrent CDAD is a persistent disease that may result in prolonged hospital stays, additional medical costs, and rare serious complications.
Prevalence and Risk Factors for Nosocomial Infections in Four University Hospitals in Switzerland
Authors: Pittet Didier , Harbarth Stephan , Ruef Christian , Francioli Patrick , Sudre Philippe , Pétignat Christiane , Trampuz Andrej , Widmer Andreas
Published: February 2006

Objective:

To determine the prevalence and risk factors for nosocomial infections (NIs) in four Swiss university hospitals.

Design and Setting:

A 1-week period-prevalence survey conducted in May 1996 in medical, surgical, and intensive-care wards of four Swiss university hospitals (900-1,500 beds). Centers for Disease Control and Prevention definitions were used, except that asymptomatic bacteriuria was not categorized as NI. Study variables included patient demographics, primary diagnosis, comorbidities, exposure to medical and surgical risk factors, and use of antimicrobials. Risk factors for NIs were determined using logistic regression with adjustment for length of hospital stay, study center, device use, and patients' comorbidities.

Results:

176 NI were recorded in 156 of 1,349 screened patients (11.6%; interhospital range, 9.8%-13.5%). The most frequent NI was surgical-site infection (53; 30%), followed by urinary tract infection (39; 22%), lower respiratory tract infection (27; 15%), and bloodstream infection (23; 13%). Prevalence of NI was higher in critical-care units (25%) than in medical (9%) and surgical wards (12%). Overall, 65% of NIs were culture-proven; the leading pathogens wereEnterobacteriaceae(44; 28%),Staphylococcus aureus(20; 13%),Pseudomonas aeruginosa(17; 11%), andCandidaspecies (16; 10%). Independent risk factors for NI were central venous catheter (CVC) use (odds ratio [OR], 3.35; 95% confidence interval [CI95], 2.91-3.80), admission to intensive care (OR, 1.75; CI95, 1.30-2.21), emergency admission (OR, 1.57; CI95, 1.15-2.00), impaired functional status (Karnofsky index 1-4: OR, 2.56; CI95, 1.95-3.17), and McCabe classification of ultimately fatal (OR, 2.50; CI95, 2.04-2.96) or rapidly fatal (OR 2.25; CI95,1.52-2.98) underlying condition.

Conclusions:

According to the results of this survey, NIs are frequent in Swiss university hospitals. This investigation confirms the importance of CVCs as a major risk factor for NI. Patient comorbidities must be taken into account to adjust for case mix in any study comparing interhospital or intrahospital infection rates.