bluuebunny/crossref_metadata_2025 huggingface dataset:
Functional Mapping of an Oligomeric Autotransporter Adhesin of
Aggregatibacter actinomycetemcomitans
Authors: Yu Chunxiao , Ruiz Teresa , Lenox Christopher , Mintz Keith P.
Published: March 2008

Extracellular matrix protein adhesin A (EmaA) is a 202-kDa nonfimbrial adhesin, which mediates the adhesion of the oral pathogen
Aggregatibacter actinomycetemcomitans
to collagen. EmaA oligomers form surface antenna-like protrusions consisting of a long helical rod with an ellipsoidal ending. The functional analysis of in-frame
emaA
deletion mutants has located the collagen binding activity to the amino terminus of the protein corresponding to amino acids 70 to 386. The level of collagen binding of this deletion mutant was comparable to the
emaA
mutant strain. Transmission electron microscopy studies indicate that the first 330 amino acids of the mature protein form the ellipsoidal ending of the EmaA protrusions, where the activity resides. Amino acid substitution analysis within this sequence has identified a critical amino acid, which is essential for the formation of the ellipsoidal ending and for collagen binding activity.
Characterization and Evolution of Cell Division and Cell Wall Synthesis Genes in the Bacterial Phyla
Verrucomicrobia
,
Lentisphaerae
,
Chlamydiae
, and
Planctomycetes
and Phylogenetic Comparison with rRNA Genes
Authors: Pilhofer Martin , Rappl Kristina , Eckl Christina , Bauer Andreas Peter , Ludwig Wolfgang , Schleifer Karl-Heinz , Petroni Giulio
Published: March 2008

In the past, studies on the relationships of the bacterial phyla
Planctomycetes
,
Chlamydiae
,
Lentisphaerae
, and
Verrucomicrobia
using different phylogenetic markers have been controversial. Investigations based on 16S rRNA sequence analyses suggested a relationship of the four phyla, showing the branching order
Planctomycetes
,
Chlamydiae
,
Verrucomicrobia
/
Lentisphaerae
. Phylogenetic analyses of 23S rRNA genes in this study also support a monophyletic grouping and their branching order—this grouping is significant for understanding cell division, since the major bacterial cell division protein FtsZ is absent from members of two of the phyla
Chlamydiae
and
Planctomycetes
. In
Verrucomicrobia
, knowledge about cell division is mainly restricted to the recent report of
ftsZ
in the closely related genera
Prosthecobacter
and
Verrucomicrobium
. In this study, genes of the conserved division and cell wall (
dcw
) cluster (
ddl
,
ftsQ
,
ftsA
, and
ftsZ
) were characterized in all verrucomicrobial subdivisions (1 to 4) with cultivable representatives (1 to 4). Sequence analyses and transcriptional analyses in
Verrucomicrobia
and genome data analyses in
Lentisphaerae
suggested that cell division is based on FtsZ in all verrucomicrobial subdivisions and possibly also in the sister phylum
Lentisphaerae
. Comprehensive sequence analyses of available genome data for representatives of
Verrucomicrobia
,
Lentisphaerae
,
Chlamydiae
, and
Planctomycetes
strongly indicate that their last common ancestor possessed a conserved, ancestral type of
dcw
gene cluster and an FtsZ-based cell division mechanism. This implies that
Planctomycetes
and
Chlamydiae
may have shifted independently to a non-FtsZ-based cell division mechanism after their separate branchings from their last common ancestor with
Verrucomicrobia
.
Protein Folding by Domain V of
Escherichia coli
23S rRNA: Specificity of RNA-Protein Interactions
Authors: Samanta Dibyendu , Mukhopadhyay Debashis , Chowdhury Saheli , Ghosh Jaydip , Pal Saumen , Basu Arunima , Bhattacharya Arpita , Das Anindita , Das Debasis , DasGupta Chanchal
Published: March 2008

The peptidyl transferase center, present in domain V of 23S rRNA of eubacteria and large rRNA of plants and animals, can act as a general protein folding modulator. Here we show that a few specific nucleotides in
Escherichia coli
domain V RNA bind to unfolded proteins and, as shown previously, bring the trapped proteins to a folding-competent state before releasing them. These nucleotides are the same for the proteins studied so far: bovine carbonic anhydrase, lactate dehydrogenase, malate dehydrogenase, and chicken egg white lysozyme. The amino acids that interact with these nucleotides are also found to be specific in the two cases tested: bovine carbonic anhydrase and lysozyme. They are either neutral or positively charged and are present in random coils on the surface of the crystal structure of both the proteins. In fact, two of these amino acid-nucleotide pairs are identical in the two cases. How these features might help the process of protein folding is discussed.
Biogenesis of the Fraction 1 Capsule and Analysis of the Ultrastructure of
Yersinia pestis
Authors: Runco Lisa M. , Myrczek Selina , Bliska James B. , Thanassi David G.
Published: March 2008

Analysis of a
Yersinia pestis
Δ
caf1A
mutant demonstrated that the Caf1A usher is required for the assembly and secretion of the fraction 1 capsule. The capsule assembled into thin fibrils and denser aggregates on the bacterial surface. Pilus-like fibers were also detected on the surface of
Y. pestis
. The capsule occasionally coated these fibers, suggesting how the capsule may cloak surface features to prevent host recognition.
Molecular Analysis of Three
Aeromonas hydrophila
AH-3 (Serotype O34) Lipopolysaccharide Core Biosynthesis Gene Clusters
Authors: Jimenez Natalia , Canals Rocío , Lacasta Anna , Kondakova Anna N. , Lindner Buko , Knirel Yuriy A. , Merino Susana , Regué Miguel , Tomás Juan M.
Published: March 2008

By the isolation of three different
Aeromonas hydrophila
strain AH-3 (serotype O34) mutants with an altered lipopolysaccharide (LPS) migration in gels, three genomic regions encompassing LPS core biosynthesis genes were identified and characterized. When possible, mutants were constructed using each gene from the three regions, containing seven, four, and two genes (regions 1 to 3, respectively). The mutant LPS core structures were elucidated by using mass spectrometry, methylation analysis, and comparison with the full core structure of an O-antigen-lacking AH-3 mutant previously established by us. Combining the gene sequence and complementation test data with the structural data and phenotypic characterization of the mutant LPSs enabled a presumptive assignment of all LPS core biosynthesis gene functions in
A. hydrophila
AH-3. The three regions and the genes contained are in complete agreement with the recently sequenced genome of
A. hydrophila
ATCC 7966. The functions of the
A. hydrophila
genes
waaC
in region 3 and
waaF
in region 2 were completely established, allowing the genome annotations of the two heptosyl transferase products not previously assigned. Having the functions of all genes involved with the LPS core biosynthesis and most corresponding single-gene mutants now allows experimental work on the role of the LPS core in the virulence of
A. hydrophila
.
La répartition et l'habitat du Tomenthypnum falcifolium au Québec–Labrador
Authors: Gauthier Robert
Published: February 2008

The discovery of Tomenthypnum falcifolium (Ren. ex Nich.) Tuom. in Canada is rather recent. For a long time, it was considered as a variety of Tomenthypnum nitens. Some characters allowing the distinction of the two species are discussed and illustrated. Distribution maps of both species in the Québec–Labrador Peninsula are presented. Habitat conditions of Tomenthypnum falcifolium in the Laurentides Park are derived from a study of peatland vegetation. It grows mainly in extremely poor fens, the dominant peatland type of this region. It is a hummock-preferring species and never forms extensive colonies. Its ecological amplitude is then rather different from that of Tomenthypnum nitens which is more commonly found in rich fens.
Formation and germination of Entomophaga maimaiga azygospores
Authors: Hajek Ann E. , Humber Richard A.
Published: February 2008

Azygospores (resting spores) of the gypsy moth fungal pathogen Entomophaga maimaiga are produced in abundance during late spring and early summer in late-instar gypsy moth larvae (Lymantria dispar). Azygospores subsequently form, each from an individual hyphal body. Development of azygospores occurs asynchronously over several days; by 5 days after host death, greater than 60% of fungal cells had matured from hyphal bodies to the final double-walled resting state. Azygospores undergo constitutive dormancy and, under field conditions, will not germinate for approximately 9 months after production. Azygospores do not require nutrients to germinate. Germination of field-collected resting spores under laboratory conditions began more than 2 days after transfer from the field to the laboratory. Higher levels of germination occurred with a 14 h L: 10 h D cycle compared with 13 h L: 11 h D or 12 h L: 12 h D. Azygospores germinate relatively slowly and germination rates were greatest between 4 and 8 days, with a total of 71.8 or 72.5% germination by 16 days at 14 h L: 10 h D and 15 or 20 °C, respectively. During 1994 and 1995, resting spores began causing infections in experimental larvae in early May, about 1 – 2 weeks prior to gypsy moth egg hatch, and ceased causing infections in mid to late June, when late instars were present. This latter timing is a correction of previously reported information. Bioassays investigating resting spore activity determined that during 1994, once resting spores began germinating in the field, levels of infection were positively associated with soil moisture. Key words: azygospores, resting spores, entomopathogenic fungi, Entomophaga maimaiga, Lymantria dispar, biological control.
Aspects of seasonal energy expenditure in the beaver (Castor canadensis Kuhl) at the northern limit of its distribution
Authors: Aleksiuk Michael , Cowan Ian McTaggart
Published: February 2008

The beaver (Castor canadensis Kuhl) is subjected to a seasonally fluctuating energy regime in the northern portion of its distribution. During the summer the animal has free access to an abundant food supply in the form of growing plant material, while the winter food supply is limited to a store of cached saplings. The summer and winter periods are 4 and 8 months long respectively.In the Mackenzie Delta. Northwest Territories, growth was found to be rapid in the summer and absent in the winter, A winter weight loss characterized immature animals. Fat was deposited in the autumn, maintained during the winter, and mobilized in the spring. Animals were lean during the summer. Thyroid gland weights were high in the summer and low in the winter. It was concluded from these data that metabolic energy expenditure is high during the summer and low during the winter. This annual pattern is an inherent property of northern beavers. The adaptive significance of the pattern. is believed to be that energy expenditure is attuned to environmental energy availability.
Cycles vitaux de quelques Plécoptères des Laurentides (insectes)
Authors: Harper Peter , Magnin Etienne
Published: February 2008

Twenty-four species of stoneflies (Plecoptera) were collected in the streams of the Station de Biologie de l'Université de Montréal, at Saint-Hippolyte in Terrebonne county (46°00′ N, 74°00′ W). Sampling of larvae and adults at regular intervals showed the distribution of the species in the stream and the seasonal succession of the adults. The Capniidae and the Taeniopterygidae appear in early spring; the remaining species emerge in May and June. The emergence of a single species Leuctra tenuis extends into July and August. No true autumnal species was found. Larval growth of the more common species is described; these are Taeniopteryx burksi, Paracapnia opis, Isoperla frisoni, Isoperla lata, Hastaperla brevis, and Paragnetina media. Biological notes concerning the other species are included.
Unusual aspects of anuran sexual behavior as seen in the red-legged frog, Rana aurora aurora
Authors: Licht Lawrence E.
Published: February 2008

When clasped by a male frog, the release behavior of an unreceptive female Rana aurora is more extensive and elaborate than that described for other anuran species. A female R. aurora cannot gain her release from a persistent male by uttering a release call which is accompanied by abdominal vibrations, the behavior effectively used by unreceptive females of other species of Rana. Instead, she extends her back legs and rolls to one side, finally remaining on her side with body and limbs stiff and outstretched.A male Rana aurora vocalizes while in amplexus with the female, and increases the speed, intensity, and repetition rate of his calls whenever the female attempts to displace him. This call by amplectic males is distinct from the normal male mating call.The advantage of an elaborate female release behavior in Rana aurora, and possible functions for the calls given by amplectic males, are discussed.
Sites of presumed neurosecretory activity in Daphnia magna Straus
Authors: Halcrow Kevin
Published: February 2008

Several regions of the nervous system of D. magna are found to contain granules stained by paraldehyde–fuchsin; these are the optic ganglion, anterior and ventral surfaces of the brain, two regions in the circumenteric connectives, and one cell at each of the junctions of the ventral nerve cords with the second ventral commissure. In the last site, variations in activity are detected.
A comparison of reproduction in two chipmunk species (Eutamias)
Authors: Sheppard David H.
Published: February 2008

Eutamias amoenus and E. minimus are potential competitors in western Alberta. The former species has larger litters and reproduces at an earlier age, on an average, than the latter. Other aspects of reproduction (breeding season, prenatal mortality) do not appear to differ greatly, though supporting data are somewhat inadequate. The higher reproductive potential should confer an advantage on amoenus in competition with minimus. The observed difference in litter size of these two congeners seems to be best explained by a difference in available food in the two habitats. This hypothesis should be tested by a comparative study of the energetics of the two species populations.
Thersitina gasterostei (Pagenstecher, 1861) (Copepoda:Ergasilidae) from Gasterosteus wheatlandi Putnam, 1867
Authors: Hanek George , Threlfall William
Published: February 2008

Thersitina gasterostei (Pagenstecher, 1861) is recorded, and figured for the first time from Gasterosteus wheatlandi Putnam, 1867. Specimens of T. gasterostei were also recovered from Gasterosteus aculeatus Linnaeus, 1758. All the fish examined were caught in Newfoundland.
Feeding processes of members of the genus Macoma (Mollusca:Bivalvia)
Authors: Reid Robert G. B. , Reid Alison
Published: February 2008

The eight species of Macoma examined fall into three feeding categories: two are deposit feeders, five are suspension feeders, and one feeds on the surface films of bacteria on sand grains. The type of particle which is found in the stomach depends on the behavior of the siphons, the quality or quantity of mucus secreted by the gills and labial palps, and, to some extent, on the sorting function of the labial palps. The labial palps act as supplementary filtering mechanisms. The stomach of M. secta, which ingests sand grains, is adapted to this diet by the enlargement of the gastric shield, but in the other species there is no obvious relationship between diet and stomach morphology.
Occurrence of Eimeria tamiasciuri in Ontario red squirrels (Tamiasciurus hudsonicus)
Authors: Soon Bee-Ling , Dorney R. S.
Published: February 2008

E. tamiasciuri is reported for the first time from Ontario (92.3% of 13 red squirrels). It resembles closely in size oocysts described from Wisconsin but is considerably smaller than those from Arizona. This extends the range of this parasite into central Canada.
Piggyback riding by pandalid shrimp larvae on hydromedusae
Authors: Marliave Jeffrey B. , Mills Claudia E.
Published: February 2008

Pandalid shrimp larvae in protected Northeast Pacific marine waters are opportunistic hitchhikers, riding piggyback on jellyfish having a bell diameter similar to the leg span of the shrimp. Ridden medusae pulsed faster and for longer periods than unridden ones. Ridden medusae rested or fed only one-third as long as they swam, whereas the resting and feeding bouts of unridden medusae normally lasted twice as long as swimming bouts. The shrimp neither damage the jellyfish nor take food from them, but many of the ridden jellyfish apparently die, perhaps because of increased energetic load.
Evidence for impaired skeletal muscle contraction-induced rapid vasodilation in aging humans
Authors: Carlson Rick E. , Kirby Brett S. , Voyles Wyatt F. , Dinenno Frank A.
Published: March 2008

We tested the hypothesis that aging is associated with an impaired contraction-induced rapid vasodilation in healthy adults. We reasoned that employing single contractions of a small muscle mass would allow us to isolate the local rapid vasodilatory responses independent of systemic hemodynamic and sympathetic neural influences on forearm hemodynamics. We measured forearm blood flow (Doppler ultrasound) and arterial blood pressure (Finapres) on a beat-by-beat basis and calculated the changes in forearm vascular conductance (ΔFVC) in response to forearm contractions in 18 young (24 ± 1 yr) and 13 older (62 ± 2 yr) healthy subjects. Single, 1-s dynamic forearm contractions were performed with the experimental arm slightly above heart level at 5, 10, 20, and 40% of the subjects' maximal voluntary contraction (MVC) in random order. In general, muscle contractions evoked a rapid increase in FVC that reached a peak within approximately four to five cardiac cycles postcontraction in both age groups. At 5% MVC, there were no significant age-related differences in contraction-induced forearm vasodilation. However, the peak vasodilatory responses were impaired ∼40–45% in older adults at 10, 20, and 40% MVC, as were the total vasodilatory responses (area under curve ∼40–50%; all P < 0.05). Additionally, the immediate vasodilation (first cardiac cycle postcontraction) for the 20% and 40% MVC trials was also impaired ∼50% with age ( P < 0.05). There were no significant age-group differences in MVC or forearm fat-free mass, and these variables were not correlated with local vasodilation within a given exercise intensity. Under the experimental conditions employed, the blunted responses with age reflect impaired local contraction-induced rapid vasodilation.
Estrogen potentiates constrictor prostanoid function in female rat aorta by upregulation of cyclooxygenase-2 and thromboxane pathway expression
Authors: Li Min , Kuo Lih , Stallone John N.
Published: March 2008

Estrogen potentiates vascular reactivity to vasopressin (VP) by enhancing constrictor prostanoid function. To determine the cellular and molecular mechanisms, the effects of estrogen on arachidonic acid metabolism and on the expression of constrictor prostanoid pathway enzymes and endoperoxide/thromboxane receptor (TP) were determined in the female rat aorta. The release of thromboxane A2(TxA2) and prostacyclin (PGI2) was measured in male (M), intact-female (Int-F), ovariectomized-female (OvX-F), and OvX + 17β-estradiol-replaced female (OvX + ER-F) rats. The expression of mRNA for cyclooxygenase (COX)-1, COX-2, thromboxane synthase (TxS), and TP by aortic endothelium (Endo) and vascular smooth muscle (VSM) of these four experimental groups was measured by RT-PCR. The expression of COX-1, COX-2, and TxS proteins by Endo and VSM was also estimated by immunohistochemistry (IHC). Basal release of TxA2and PGI2was similar in M (18.8 ± 1.9 and 1,723 ± 153 pg/mg ring wt/45 min, respectively) and Int-F (20.2 ± 4.2 and 1,488 ± 123 pg, respectively) rat aortas. VP stimulated the dose-dependent release of TxA2and PGI2from both male and female rat aorta. OvX markedly attenuated and ER therapy restored VP-stimulated release of TxA2and PGI2in female rats. No differences in COX-1 mRNA levels were detected in either Endo or VSM of the four experimental groups ( P > 0.1). The expression of both COX-2 and TxS mRNA were significantly higher ( P < 0.05) in both Endo and VSM of Int-F and OvX + ER-F, compared with M or OvX-F. Expression of TP mRNA was significantly higher in VSM of Int-F and OvX + ER-F compared with M or OvX-F. IHC revealed the uniform staining of COX-1 in VSM of the four experimental groups, whereas staining of COX-2 and TxS was greater in Endo and VSM of Int-F and OvX + ER-F than in OvX-F or M rats. These data reveal that estrogen enhances constrictor prostanoid function in female rat aorta by upregulating the expression of COX-2 and TxS in both Endo and VSM and by upregulating the expression of TP in VSM.
Integrative control of coronary resistance vessel tone by endothelin and angiotensin II is altered in swine with a recent myocardial infarction
Authors: de Beer Vincent J. , Sorop Oana , Pijnappels Daniël A. , Dekkers Dick H. , Boomsma Frans , Lamers Jos M. J. , Duncker Dirk J. , Merkus Daphne
Published: March 2008

Several studies have indicated an interaction between the renin-angiotensin (ANG II) system and endothelin (ET) in the regulation of vascular tone. Previously, we have shown that both ET and ANG II exert a vasoconstrictor influence on the coronary resistance vessels of awake normal swine. Here, we investigated whether the interaction between ANG II and ET exists in the control of coronary resistance vessel tone at rest and during exercise using single and combined blockade of angiotensin type 1 (AT1) and ETA/ETB receptors. Since both circulating ANG II and ET levels are increased after myocardial infarction (MI), we investigated if the interaction between these systems is altered after MI. In awake healthy swine, coronary vasodilation in response to ETA/ETB receptor blockade in the presence of AT1 blockade was similar to vasodilation produced by ETA/ETB blockade under control conditions. In awake swine with a 2- to 3-wk-old MI, coronary vasodilator responses to individual AT1 and ETA/ETB receptor blockade were virtually abolished, despite similar coronary arteriolar AT1 and ETA receptor expression compared with normal swine. Unexpectedly, in the presence of AT1 blockade (which had no effect on circulating ET levels), ETA/ETB receptor blockade elicited a coronary vasodilator response. These findings suggest that in normal healthy swine the two vasoconstrictor systems contribute to coronary resistance vessel control in a linear additive manner, i.e., with negligible cross-talk. In contrast, in the remodeled myocardium, cross-talk between ANG II and ET emerges, resulting in nonlinear redundant control of coronary resistance vessel tone.
Hsc70 regulates cell surface ASIC2 expression and vascular smooth muscle cell migration
Authors: Grifoni Samira C. , McKey Susan E. , Drummond Heather A.
Published: March 2008

Recent studies suggest members of the degenerin (DEG)/epithelial Na+channel (ENaC)/acid-sensing ion channel (ASIC) protein family play an important role in vascular smooth muscle cell (VSMC) migration. In a previous investigation, we found suppression of a certain DEG/ENaC/ASIC member, ASIC2, increased VSMC chemotactic migration, raising the possibility that ASIC2 may play an inhibitory role. Because ASIC2 protein was retained in the cytoplasm, we reasoned increasing surface expression of ASIC2 might unmask the inhibitory role of ASIC2 in VSMC migration so we could test the hypothesis that ASIC2 inhibits VSMC migration. Therefore, we used the chemical chaperone glycerol to enhance ASIC2 expression. Glycerol 1) increased cytoplasm ASIC2 expression, 2) permitted detection of ASIC2 at the cell surface, and 3) inhibited platelet-derived growth factor (PDGF)-bb mediated VSMC migration. Furthermore, ASIC2 silencing completely abolished the inhibitory effect of glycerol on migration, suggesting upregulation of ASIC2 is responsible for glycerol-induced inhibition of VSMC migration. Because other investigators have shown that glycerol regulates ENaC/ASIC via interactions with a certain heat shock protein, heat shock protein 70 (Hsc70), we wanted to determine the importance of Hsc70 on ASIC2 expression in VSMCs. We found that Hsc70 silencing increases ASIC2 cell surface expression and inhibits VSMC migration, which is abolished by cosilencing ASIC2. These data demonstrate that Hsc70 inhibits ASIC2 expression, and, when the inhibitory effect of Hsc70 is removed, ASIC2 expression increases, resulting in reduced VSMC migration. Because VSMC migration contributes to vasculogenesis and remodeling following vascular injury, our findings raise the possibility that ASIC2-Hsc70 interactions may play a role in these processes.
Improved ECG detection of presence and severity of right ventricular pressure load validated with cardiac magnetic resonance imaging
Authors: Henkens Ivo R. , Mouchaers Koen T. B. , Vonk-Noordegraaf Anton , Boonstra Anco , Swenne Cees A. , Maan Arie C. , Man Sum-Che , Twisk Jos W. R. , van der Wall Ernst E. , Schalij Martin J. , Vliegen Hubert W.
Published: March 2008

The study aimed to assess whether the 12-lead ECG-derived ventricular gradient, a vectorial representation of ventricular action potential duration heterogeneity directed toward the area of shortest action potential duration, can improve ECG diagnosis of chronic right ventricular (RV) pressure load. ECGs from 72 pulmonary arterial hypertension patients recorded <30 days before onset of therapy were compared with ECGs from matched healthy control subjects ( n = 144). Conventional ECG criteria for increased RV pressure load were compared with the ventricular gradient. In 38 patients a cardiac magnetic resonance (CMR) study had been performed within 24 h of the ECG. By multivariable analysis, combined use of conventional ECG parameters (rsr′ or rsR′ in V1, R/S > 1 with R > 0.5 mV in V1, and QRS axis >90°) had a sensitivity of 89% and a specificity of 93% for presence of chronic RV pressure load. However, the ventricular gradient not only had a higher diagnostic accuracy for chronic RV pressure load by receiver operating characteristic analysis [areas under the curve (AUC) = 0.993, SE 0.004 vs. AUC = 0.945, SE 0.021, P < 0.05], but also discriminated between mild-to-moderate and severe RV pressure load. CMR identified an inverse relation between the ventricular gradient and RV mass, and a trend toward a similar relation with RV volume. In conclusion, chronically increased RV pressure load is electrocardiographically reflected by an altered ventricular gradient associated with RV remodeling-related changes in ventricular action potential duration heterogeneity. The use of the ventricular gradient allows ECG detection of even mildly increased RV pressure load.
Sympathy for the devil: the role of thromboxane in the regulation of vascular tone and blood pressure
Authors: Sellers Minga M. , Stallone John N.
Published: March 2008

Historically, the vasodilatory prostanoids, especially prostacyclin and prostaglandin E2, are believed to contribute significantly to the regulation of normal vascular tone and blood pressure (BP), primarily by counteracting the prevailing effects of the systemic vasoconstrictor systems, including angiotensin II, the catecholamines, and vasopressin. In contrast, the primary vasoconstrictor prostanoid thromboxane A2(TxA2) is produced in far smaller quantities in the normal state. While TxA2is believed to play a significant role in a variety of cardiovascular diseases, such as myocardial infarction, cerebral vasospasm, hypertension, preeclampsia, and various thrombotic disorders, its role in the regulation of vascular tone and BP in the normal physiological state is, at best, uncertain. Numerous studies have firmly established the dogma that TxA2, while important in pathophysiological states in males, plays little or no role in the regulation of vascular tone or BP in females, except in the pulmonary vasculature. However, this concept is largely based on the predominant and preferential use of males in animal and human studies. Recent studies from our laboratory and others challenge this dogma and reveal that the TxA2pathway in the systemic vascular wall is an estrogen-dependent mechanism that appears to play an important role in the regulation of vascular tone and BP in females, in both normal and pathophysiological states. It is proposed that the potent vasoconstrictor action of TxA2is beneficial in the female in the normal state by acting as a local counterregulatory mechanism to increase vascular tone and BP and defend against hypotension that could result from the multiple estrogen-sensitive local vasodilator mechanisms present in the female vascular wall. Validation of this proposal must await further studies at the systemic, tissue, and molecular levels.
Intra-alveolar tissue factor pathway inhibitor is not sufficient to block tissue factor procoagulant activity
Authors: Bastarache Julie A. , Wang Ling , Wang Zhengming , Albertine Kurt H. , Matthay Michael A. , Ware Lorraine B.
Published: March 2008

The alveolar compartment in acute lung injury contains high levels of tissue factor (TF) procoagulant activity favoring fibrin deposition. We previously reported that the alveolar epithelium can release TF procoagulant activity in response to a proinflammatory stimulus. To test the hypothesis that the alveolar epithelium further modulates intra-alveolar fibrin deposition through secretion of an endogenous inhibitor to TF, tissue factor pathway inhibitor (TFPI), we measured TFPI levels in edema fluid (EF) from patients with acute respiratory distress syndrome. To determine whether the alveolar epithelium can release TFPI, both full-length TFPI and truncated TFPI were measured (ELISA) in pulmonary edema fluid from patients with acute respiratory distress syndrome (ARDS) and a control group of patients with hydrostatic pulmonary edema (HYDRO). TFPI protein was also measured in conditioned media (CM) and cell lysates (CL) from human alveolar epithelial cells (A549) after exposure to cytomix (TNF-α, IL-1β, IFN-γ). TFPI protein levels were higher in pulmonary edema fluid from patients with ARDS vs. HYDRO. TFPI protein was increased in CM and did not change in CL after cytomix treatment; TFPI mRNA levels (RT-PCR) did not change. Despite the high levels of TFPI, both the EF and CM retained significant TF procoagulant activity as measured by plasma recalcification time. The majority of intra-alveolar TFPI was in a truncated, inactive form, whereas the majority of TFPI released from cells was full length, suggesting different mechanisms of inactivation. In summary, the alveolar epithelium releases TFPI in response to an inflammatory stimulus but does not increase TFPI gene transcription or protein production. Levels of intra-alveolar TFPI in ARDS are not sufficient to block intra-alveolar TF procoagulant activity due to truncation and inactivation of intra-alveolar TFPI.
Prostasin expression is regulated by airway surface liquid volume and is increased in cystic fibrosis
Authors: Myerburg Mike M. , McKenna Erin E. , Luke Cliff J. , Frizzell Raymond A. , Kleyman Thomas R. , Pilewski Joseph M.
Published: March 2008

Airway surface liquid (ASL) absorption is initiated by Na+entry via epithelial Na+channels (ENaC), which establishes an osmotic gradient that drives fluid from the luminal to serosal airway surface. We and others have recently reported that a protease/anti-protease balance regulates ENaC in human airway epithelial cells (HAEC) and provides a mechanism for autoregulation of ASL volume. In cystic fibrosis (CF), this balance is disturbed, leading to constitutive proteolytic activation of ENaC and the pathological Na+hyperabsorption characteristic of this airway disease. Prostasin is a glycosylphosphatidylinositol-anchored serine protease that activates ENaC and is expressed on the surface epithelium lining the airway. In this report we present evidence that prostasin expression is regulated by the ASL volume, allowing for increased proteolytic activation of ENaC when the ASL volume is high. Prostasin activity is further regulated by the cognate serpin protease nexin-1 (PN-1), which is expressed in HAEC and inhibits Na+absorption by forming an inactive complex with prostasin and preventing the proteolytic processing of prostasin. Whereas these mechanisms regulate prostasin expression in response to ASL volume in non-CF epithelia, HAEC cultured from CF patients express >50% more prostasin on the epithelial surface. These findings suggest that a proteolytic cascade involving prostasin, an upstream prostasin-activating protease, and PN-1 regulate Na+absorption in the airway and that abnormal prostasin expression contributes to excessive proteolytic activation of ENaC in CF patients.
Three Stories from the Trenches: The Theatre of the Oppressed in the Midst of War
Authors: Paterson Doug
Published: February 2008

From Israel, Liberia, and Iraq, where conflict and war are the rule, come stories about performances and workshops in the tradition of Augusto Boal's Theatre of the Oppressed. The author found both strengths and limitations in Forum Theatre.
Telling and Showing: Witnesses Represent Sierra Leone's War Atrocities in Court and Onstage
Authors: Stepakoff Shanee
Published: February 2008

After a brutal civil war in Sierra Leone, a young prosecution witness in a war crimes tribunal in Freetown created, directed, and performed a drama that graphically portrays the trauma she and her fellow survivors experienced during the war. Stepakoff was the psychologist for the Special Court for Sierra Leone—working with victims of severe human rights violations—and an invited guest at the young woman's performance.
Border Hysteria and the War against Difference
Authors: Gómez-Peña Guillermo
Published: February 2008

This issue's Critical Acts focuses on “war and other bad shit” in terms of censorship, immigration, and art as a form of political protest and recovery. In “Habeas Corpus,” Ann Pellegrini uses Sally Field's censored Emmy-acceptance speech to exemplify the Bush administration's privatization of mourning as a means “to bind us to acts of fatal violence against an objectified and dehumanized ‘enemy.’” In her account of Luigi Nono's The Forest Is Young and Full of Life, Judy Lochhead examines the possibility of music as activism, noting how history is recycled from the Vietnam War to today. William Bowling and Rachel Carrico describe how art heals in Lakeviews, part of a post-Katrina project. Guillermo Gómez-Peña rages against “border hysteria,” when the “War on Terror” becomes a “war on difference.”
Atlantic Dominance of the Meridional Overturning Circulation
Authors: de Boer A. M. , Toggweiler J. R. , Sigman D. M.
Published: February 2008

North Atlantic (NA) deep-water formation and the resulting Atlantic meridional overturning cell is generally regarded as the primary feature of the global overturning circulation and is believed to be a result of the geometry of the continents. Here, instead, the overturning is viewed as a global energy–driven system and the robustness of NA dominance is investigated within this framework. Using an idealized geometry ocean general circulation model coupled to an energy moisture balance model, various climatic forcings are tested for their effect on the strength and structure of the overturning circulation. Without winds or a high vertical diffusivity, the ocean does not support deep convection. A supply of mechanical energy through winds or mixing (purposefully included or due to numerical diffusion) starts the deep-water formation. Once deep convection and overturning set in, the distribution of convection centers is determined by the relative strength of the thermal and haline buoyancy forcing. In the most thermally dominant state (i.e., negligible salinity gradients), strong convection is shared among the NA, North Pacific (NP), and Southern Ocean (SO), while near the haline limit, convection is restricted to the NA. The effect of a more vigorous hydrological cycle is to produce stronger salinity gradients, favoring the haline state of NA dominance. In contrast, a higher mean ocean temperature will increase the importance of temperature gradients because the thermal expansion coefficient is higher in a warm ocean, leading to the thermally dominated state. An increase in SO winds or global winds tends to weaken the salinity gradients, also pushing the ocean to the thermal state. Paleoobservations of more distributed sinking in warmer climates in the past suggest that mean ocean temperature and winds play a more important role than the hydrological cycle in the overturning circulation over long time scales.
Appropriate Antibiotic Use for Acute Otitis Media: What Consumers Find Using Web Searches
Authors: Holland Margaret L. , Fagnano Maria
Published: March 2008

The use of the Internet for health information is growing, but there is little control over the timeliness of updates or the accuracy of the information. Recent changes in recommendations for the treatment of acute otitis media were made in an effort to decrease the unnecessary use of antibiotics. We conducted a systematic review of Web sites to determine if consumers are likely to find appropriate information. Only 31% of relevant Web sites found explain the new “watch and wait” recommendation, and 41% include a recommendation to finish the full course of prescribed antibiotics. Web sites that include an update date, are reviewed by a physician, provide references, and have a nonprofit-type domain are more likely to contain updated information. Physicians should be aware that their patients might visit the office with expectations based on outdated information found on the Web. Organizations making recommendations should consider how to disseminate new information through the Web.
Social and Subcultural Capital Among Teenagers in Northern Ireland
Authors: Leonard Madeleine
Published: March 2008

This article makes a case for the inclusion of subcultural capital as an indictor of social capital networks in the lives of teenagers. It does so by critiquing approaches that assume that adult measures of social capital can be nonproblematically extended to account for stocks of social capital held by younger generations. To illustrate the fallacy of this approach, this article draws on data from the 2003 Northern Ireland Young Life and Times Survey (NIYLTS) and the indicators used to explore the relevance of social capital in the lives of teenagers. By ignoring concepts such as subcultural capital, surveys such as the NILYTS provide partial frameworks for understanding the complexities of young people's links to social capital networks and their inclusive and exclusive effects.
Biased Information Search in Homogeneous Groups: Confidence as a Moderator for the Effect of Anticipated Task Requirements
Authors: Kerschreiter Rudolf , Schulz-Hardt Stefan , Mojzisch Andreas , Frey Dieter
Published: March 2008

When searching for information, groups that are homogeneous regarding their members' prediscussion decision preferences show a strong bias for information that supports rather than conflicts with the prevailing opinion (confirmation bias). The present research examined whether homogeneous groups blindly search for information confirming their beliefs irrespective of the anticipated task or whether they are sensitive to the usefulness of new information for this forthcoming task. Results of three experiments show that task sensitivity depends on the groups' confidence in the correctness of their decision: Moderately confident groups displayed a strong confirmation bias when they anticipated having to give reasons for their decision but showed a balanced information search or even a dis confirmation bias (i.e., predominately seeking conflicting information) when they anticipated having to refute counterarguments. In contrast, highly confident groups demonstrated a strong confirmation bias independent of the anticipated task requirements.
Response of Knee Ligaments to Prolotherapy in a Rat Injury Model
Authors: Jensen Kristina T. , Rabago David P. , Best Thomas M. , Patterson Jeffrey J. , Vanderby Ray
Published: March 2008

Background

Prolotherapy is an alternative therapy for chronic musculoskeletal injury including joint laxity. The commonly used injectant, D-glucose (dextrose), is hypothesized to improve ligament mechanics and decrease pain through an inflammatory mechanism. No study has investigated the mechanical effects of prolotherapy on stretch-injured ligaments.

Hypotheses

Dextrose injections will enlarge cross-sectional area, decrease laxity, strengthen, and stiffen stretch-injured medial collateral ligaments (MCLs) compared with controls. Dextrose prolotherapy will increase collagen fibril diameter and density of stretch-injured MCLs.

Study Design

Controlled laboratory study.

Methods

Twenty-four rats were bilaterally MCL stretch-injured, and the induced laxity was measured. After 2 weeks, 32 MCLs Were injected twice, 1 week apart, with either dextrose or saline control; 16 MCLs received no injection. Seven uninjured rats (14 MCLs) were additional controls. Two weeks after the second injection, ligament laxity, mechanical properties (n = 8), and collagen fibril diameter and density (n = 3) were assessed.

Results

The injury model created consistent ligament laxity ( P < .05) that was not altered by dextrose injections. Cross-sectional area of dextrose-injected MCLs was increased 30% and 90% compared with saline and uninjured controls, respectively ( P < .05). Collagen fibril diameter and density were decreased in injured ligaments compared with uninjured controls ( P < .05), but collagen fibril characteristics were not different between injured groups.

Conclusion

Dextrose injections increased the cross-sectional area of MCLs compared with saline-injected and uninjured controls. Dextrose injections did not alter other measured properties in this model.

Clinical Relevance

Our results suggest that clinical improvement from prolotherapy may not result from direct effects on ligament biomechanics.
Optimization of Graft Fixation at the Time of Anterior Cruciate Ligament Reconstruction
Authors: Mae Tatsuo , Shino Konsei , Nakata Ken , Toritsuka Yukiyoshi , Otsubo Hidenori , Fujie Hiromichi
Published: March 2008

Background

Although anterior cruciate ligament (ACL) reconstructions are frequently performed, little is known about the effect of initial tension on an ACL graft at the time of its fixation.

Purpose

The objective of this study was to evaluate the effects of initial tension on the relative position and the load between femur and tibia during passive motion.

Study Design

Controlled laboratory study.

Methods

Seven cadaveric knees underwent a passive flexion-extension movement from 0° to 90° with a robotic system developed in the authors’ laboratory under 6 degrees of freedom, while their 3-dimensional paths were recorded. A single-socket ACL reconstruction was performed with an autogenous quadrupled hamstring tendon graft, while the knees underwent the same movement as before with the initial graft tension of 22 N (group A), 44 N (group B), or 88 N (group C) at 20°. The relative position between the femur and the tibia was recorded, and the load in the femorotibial joint was calculated using the principle of superposition.

Results

The tibia in group C was most posteriorly positioned among the 3 groups (an average posterior translation of 0.6, 1.3, and 2.6 mm in groups A, B, and C, respectively). The tibia also moved proximally and laterally with external and valgus rotation with an increase in initial tension, and consequently the load in the femorotibial joint increased at ail flexion angles.

Conclusion

With an increase in initial tension, the tibia moved posterolaterally with external and valgus rotation, and consequently the contact force in the femorotibial joint increased.

Clinical Relevance

Excessive initial tension at the time of ACL reconstruction may potentially bring deleterious effects to the articular surface, leading to cartilage degeneration.
Will the Boomers Volunteer During Retirement? Comparing the Baby Boom, Silent, and Long Civic Cohorts
Authors: Einolf Christopher J.
Published: March 2008

Data from the 1995 and 2005 waves of the Midlife in the United States panel study were used to compare rates of volunteering among the baby boomers with earlier cohorts and to predict boomers' future volunteering. When age was kept constant through the use of panel data, the first baby boom cohort (born 1946 to 1955) did more volunteering than did the “silent” cohort (born 1936 to 1945), and the silents volunteered more than did the “long civic” cohort (born 1926 to 1935). The author generated regression equations that used nine 1995 variables to predict 2005 volunteering and used the boomers' 2005 values on these variables to predict their 2015 volunteering. These equations slightly predict higher volunteering among the boomers in 2015 than the silents did in 2005. This result, combined with the large size of the boomer cohort, indicates that the total number of elderly volunteers will probably increase in the next decade.
Allocating Lobbying Resources between Collective and Private Rents
Authors: Godwin R. Kenneth , Lopez Edward J. , Seldon Barry J.
Published: March 2008

How do firms allocate their lobbying resources among their political goals? The authors approach this question using a game-theoretic model that integrates three concepts from the lobbying literature: the distinction between private and collective rents, the competition for a rent, and the impacts of political institutions. The model indicates how competition and political institutions affect lobbying expenditures and expected net returns for private and collective lobbying. The outcomes predicted differ with those of past formal models and produce the counterintuitive expectation that competition typically reduces expenditures. The authors test the model's predictions by examining the lobbying decisions of sixty-two firms.
Strong Civil Society as a Double-Edged Sword
Authors: Aldrich Daniel P. , Crook Kevin
Published: March 2008

To meet the dire need for housing following Hurricane Katrina, New Orleans and Federal Emergency Management Agency officials created lists of potential sites for trailer parks. We analyze approved sites to track which factors were linked with larger (or smaller) numbers of trailers and trailer sites per zip code block. Areas which displayed greater levels of social capital, as evidenced by voluntaristic activities such as voting, were slated for fewer trailers, controlling for race, income, education, flood damage, and other relevant factors. Civil society worked simultaneously to bring citizens together while mobilizing them against the threat of trailer parks in their backyards.
The “Other” Gender?
Authors: Falen Douglas J.
Published: March 2008

While there are undoubtedly real barriers to men doing research on women, these barriers loom larger than they are. Despite the deconstruction of essentialized gender categories, the anthropology of gender and women continue to be the domain of women. This reflexive account of anthropological fieldwork among women in Benin documents the mistakes and successes the author has experienced, while arguing that the challenges exist not only in the field setting, but in the Academy and in the ethnographer's mind. The essay concludes with a plea to reinvigorate the anthropology of gender by attending to the possibilities for men to understand women's lives both through interaction with men as well as with women.
The Things We Carry
Authors: Brandes Stanley
Published: March 2008

This article takes as its starting point Tim O'Brien's famous essay, “The Things They Carried,” a fictional evocation of tangible and intangible items that Vietnam War soldiers hauled around with them in the field. “The Things We Carry,” by contrast, analyzes the theoretical ideas and various components of social identity that anthropologists bring with them to the communities in which they carry out research. This article focuses especially on the author's status as a young married male conducting fieldwork in the part of southern Spain known as Andalusia. Access to field data did not depend in this case solely on the social structure and prevalent ideology of the community itself. Rather, the social and intellectual attributes of the author—that which he carried with him—proved crucial in guiding the research outcome.