bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of Technetium‐99m Sestamibi Imaging on the Emergency Department Management and Costs in the Evaluation of Low‐risk Chest Pain
Authors: Kosnik Joseph W. , Zalenski Robert J. , Grzybowski Mary , Huang Raywin , Sweeny Padraic J. , Welch Robert D.
Published: January 2008

Abstract. Objectives: To assess the impact of rest sestamibi scanning on emergency physicians' (EPs') diagnostic certainty and decision making (as assessed by the hypothetical disposition of patients) for 69 consenting stable patients with suspected acute cardiac ischemia and nondiagnostic electrocardiograms. The resultant impact on costs was examined as a secondary outcome. Methods: Patients with suspected acute cardiac ischemia were injected with 25 mCi of sestamibi within two hours of active pain in one of three emergency department study sites. The probability of acute myocardial infarction (AMI) and unstable angina (UA), and hypothetical disposition decisions were recorded immediately before and after physicians were notified of scan results. Changes in disposition were classified as optimal or suboptimal. For the cost determinations, a cost‐based decision support program was used. Results: For the subgroup found to be free of acute cardiac events (ACEs) (n= 62), the EPs' post‐sestamibi scan probabilities for AMI decreased by 11% and UA by 18% (p < 0.001 for both conditions). In seven patients with ACEs, the post‐scan probabilities of AMI and UA increased, but neither was statistically significant. Scan results led to hypothetical disposition changes in 29 patients (42%), of which 27 (93%) were optimal (nine patients were reassigned to a lower level of care, two to a higher level, and 16 additional patients to “discharge‐home” status). The strategy of scanning all patients who were low to moderate risk for acute cardiac ischemia would result in an increase of direct costs of care of $222 per patient evaluated, due to added cost of sestamibi scanning. Conclusions: Sestamibi scanning results appropriately affected the EPs' estimates of the probability of AMI and UA and improved disposition decisions. Scanning all low‐risk patients would likely be associated with increased costs at this medical center.
Emergency Department Right Upper Quadrant Ultrasound Is Associated with a Reduced Time to Diagnosis and Treatment of Ruptured Ectopic Pregnancies
Authors: Rodgerson Jeff D. , Heegaard William G. , Plummer Dave , Hicks Jason , Clinton Joseph , Sterner Steven
Published: January 2008

Abstract. Objective: To determine whether the time to diagnosis and treatment of patients with ruptured ectopic pregnancy is significantly less for patients who had emergency department (ED) right upper quadrant (RUQ) ultrasound (US) compared with those who had US in the radiology department. Methods: The authors conducted a retrospective review of eligible patients presenting to an urban ED between January 1990 and December 1998. Patients were included in the study if they were seen in the ED, had a discharge diagnosis of ruptured ectopic pregnancy, were brought immediately to the operating room after a definitive diagnosis of ectopic pregnancy rupture was made, and had more than 400 mL of intraperitoneal blood found at the time of surgery. The ED, hospital, radiology, and operative records were reviewed to determine presenting vital signs, intraperitoneal blood loss, time to diagnosis, time to treatment, and type of US performed. Results: There were 37 patients enrolled; 16 received ED RUQ US (group I) and 21 had a formal US in radiology (group II). The ages, pulses, systolic blood pressures, and volumes of hemoperitoneum were similar between the two groups. The average time to diagnosis from ED arrival was 58 minutes for group I (SD = 57; 95% CI = 28 to 87) and 197 minutes for group II (SD = 82; 95% CI = 162 to 232) (p ≤ 0.0001). The average time to operative treatment was 111 minutes (group I) (SD = 86; 95% CI = 69 to 153) and 322 minutes (group II) (SD = 107; 95% CI = 270 to 364) (p ≤ 0.0001), respectively. Conclusions: Patients with ruptured ectopic pregnancy, who were selected to have RUQ US performed in the ED by emergency physicians, had an average decrease in time to diagnosis of two and a quarter hours, and an average decrease in time to treatment of three and a half hours, compared with those having a formal pelvic US in the radiology department. Further prospective investigation is needed to determine whether ED RUQ US can safely expedite care of patients with suspected ectopic pregnancy.
Sonographic Features of Small‐bowel Intussusception in Pediatric Patients
Authors: Tiao Mao‐Meng , Wan Yung‐Liang , Ng Shu‐Hang , Ko Sheung‐Fat , Lee Tze‐Yu , Chen Min‐Chi , Shieh Chie‐Song , Chuang Jiin‐Huar
Published: January 2008

Abstract. Objective: Small‐bowel intussusception (SBI) for pediatric patients is unusual and difficult to diagnose preoperatively. This study sought to determine the sonographic findings of pediatric SBI. Methods: The sonographic features and surgical findings of 13 pediatric patients (7 boys, 6 girls; age range 4 months‐15 years; average age 4 years and 2 months) with SBI encountered in the authors' hospital over a 12‐year period were retrospectively reviewed. Results: Most of the patients presented with nonspecific symptoms, including vomiting, abdominal pain, and/or irritable crying. Sonographic screening in the emergency department revealed a doughnut or crescent‐in‐doughnut sign, or a multiple‐concentric‐rings sign for 11 of the 13 patients, and the lesions appeared short. Eight lesions were found in the paraumbilical or left abdominal regions. Sonographic measurement of the size of the lesions from these 11 patients ranged from 2 cm to 3.7 cm (average 2.77 cm). Subsequent barium enemas were performed for these 11 patients, none of which revealed colon lesions. Surgery revealed ileoileal intussusceptions for eight cases, jejunoileal for three, and jejunojejunal for the remaining two. Bowel ischemia or necrosis and pathologic lead points were demonstrated for seven and six patients, respectively, although none were recognized preoperatively. Conclusions: Small‐bowel intussusception is often over‐looked due to nonspecific clinical presentations. Sonographic demonstration of a 2‐3‐cm sized, short, doughnut‐like lesion, especially in the left abdomen or paraumbilical regions, should lead to strong suspicion of SBI.
Evaluating Paramedic Comfort with Field Pronouncement: Development and Validation of an Outcome Measure
Authors: Morrison Laurie J. , Cheung Matthew C. , Redelmeier Donald A.
Published: January 2008

Objectives: Interventions designed to improve cardiac resuscitation and the quality of field pronouncement need to consider outcomes on paramedic providers. The authors developed and evaluated the reliability and validity of a survey instrument measuring paramedic comfort with field pronouncement. Methods: A mail survey of 120 paramedics (EMT‐Ps) was performed using the Modified Dillman survey methodology. Questions were sorted for analysis into subgroups assessing psychological comfort and technical skills. Sixty‐five respondents were retested within two weeks. Results: The overall response rate was 96% (115). Respondents had an average age of 36 years (SD ± 5), with 5.2 years (SD ± 3.8) of out‐of‐hospital experience as an EMT‐P, and were involved in a median of ten field pronouncements annually (range = 2–60). The face and content validity of the survey instrument was consistent with a content matrix derived by a focus group. The Cronbach's alpha for the survey instrument was 0.91. The retest response rate was 76% (46). The test–retest reliability coefficient was 0.84. Conclusions: This survey is a valid and reliable instrument for measuring the paramedic psychological comfort with field pronouncement. The high response rate and intrareliability support its generalizability. This outcome measure may be helpful in evaluating the psychological impact of changes to emergency medical services (EMS) policy with respect to termination of resuscitation promoted by the National Association of EMS Physicians.
Bispectral Electroencephalographic Analysis of Patients Undergoing Procedural Sedation in the Emergency Department
Authors: Miner James R. , Biros Michelle H. , Heegaard William , Plummer David
Published: January 2008

Objective: To determine whether there is a correlation between the level of sedation achieved during procedural sedation (PS) in the emergency department as determined by bispectral electroencephalographic (EEG) analysis (BIS) and the rate of respiratory depression (RD), the patient's perception of pain, recall of the procedure, and satisfaction. Methods: This was a prospective observational study conducted in an urban county hospital of adult patients undergoing PS using propofol, methohexital, etomidate, and the combination of fentanyl and midazolam. Consenting patients were monitored by vital signs, pulse oximetry, nasal‐sample end‐tidal carbon dioxide (ETCO2), and BIS monitors during PS. Respiratory depression (RD) was defined as an oxygen saturation <90%, a change from baseline ETCO2 of >10 mm Hg, or an absent ETCO2 waveform at any time during the procedure. After the procedure, patients were asked to complete three 100‐mm visual analog scales (VASs) concerning their perception of pain, recall of the procedure, and satisfaction with the procedure. Patients were divided into four groups based on the lowest BIS score recorded during the procedure, group 1, >85; group 2, 70–85; group 3, 60–69; group 4, <60. Rates of RD and VAS outcomes were compared between groups using chi‐square statistics. Results: One hundred eight patients were enrolled in the study. No serious adverse events were noted. RD was seen in three of 14 (21.4%) of the patients in group 1, seven of 34 (20.6%) in group 2, 16 of 26 (61.5%) in group 3, and 18 of 34 (52.9%) in group 4. The rate of RD in patients in group 2 was not significantly different from that in group 1 (p = 0.46). The rate of RD in group 2 was significantly lower than that in groups 3 (p = 0.0003) and 4 (p = 0.006). For the VAS data, when group 1 was compared with the combined groups 2, 3, and 4, it had significantly higher rates of pain (p = 0.003) and recall (p = 0.001), and a dissatisfaction rate (p = 0.085) that approached significance. When groups 2, 3, and 4 were compared with chi‐square test, there was not a significant difference in pain (p = 0.151), recall (p = 0.27), or satisfaction (p = 0.25). Conclusions: Patients with a lowest recorded BIS score between 70 and 85 had the same VAS outcomes as more deeply sedated patients and the same rate of RD as less deeply sedated patients. This range of scores represented the optimally sedated patients in this study.
Emergency Medicine Animal Research: Does Use of Randomization and Blinding Affect the Results?
Authors: Bebarta Vik , Luyten Dylan , Heard Kennon
Published: January 2008

Objectives: It has been shown that human clinical trials that lack randomization (RND) or blinding (BLD) often overestimate the magnitude of treatment effects. However, no studies have evaluated the effect of RND and BLD on animal research. The authors' objectives were to determine the proportion of animal studies presented at a national academic emergency medicine meeting that utilize randomization, blinding, or both; and to determine whether failure to employ these techniques changes the likelihood of observing a difference between treatment groups. Methods: Two trained researchers reviewed abstracts presented at the 1997–2001 Society for Academic Emergency Medicine (SAEM) annual meetings using a standard data collection sheet. Studies that used an animal or cell line, compared two or more study groups, and measured an effect caused by the intervention or drugs were included. Studies were classified as randomized (RND+) if any part of the experiment involved random assignment of subjects to treatment groups, blinded (BLD+) if any assessment of the outcome was made by an investigator blinded to treatment group, and outcome‐positive (Outcome+) if any difference between the study groups met the author's definition of significant. Following the initial review, differences in classification were resolved by consensus. The association between outcome and study methodology (RND, BLD or both) was measured using odds ratios (ORs) with 95% confidence intervals (95% CIs). Results: A total of 2,592 studies were published as abstracts. Three hundred eighty‐nine were animal studies, and 290 of these studies had two or more study groups. RND− and BLD− studies were more likely to be Outcome+ than RND+ or BLD+ studies (OR = 3.4; 95% CI = 1.7 to 6.9 and OR = 3.2; 95% CI = 1.3 to 7.7, respectively). When studies that used both RND and BND were compared with studies that used neither, the OR for a positive study was 5.2 (95% CI = 2.0 to 13.5). Conclusions: These results suggest that animal studies that do not utilize RND and BLD are more likely to report a difference between study groups than studies that employ these methods.
Efficacy of an Educational Web Site for Educating Physicians about Bioterrorism
Authors: Chung Sarita , Mandl Kenneth D. , Shannon Michael , Fleisher Gary R.
Published: January 2008

Objectives: To determine whether a Web‐based educational intervention improves emergency physicians' knowledge about bioterrorism and to survey physicians' knowledge and sources of information on bioterrorism. Methods: Prospective randomized controlled trial using pre‐ and postintervention testing in hospitals. Participants were general and pediatric emergency medicine attending physicians, fellows, and fourth‐year emergency medicine residents. All participants completed a pretest and attended a lecture on bioterrorism. Participants were then randomized to the Web intervention group that received continuous access to a bioterrorism educational Web site with weekly exposure to case scenarios of diseases due to biological agents, or the control group. Participants were retested after one and six months and surveyed to identify their sources of information and assess their knowledge. Results: Sixty‐three physicians completed the pretest. There was no difference in mean ± standard deviation (SD) pretest scores between Web intervention (45%± 10%) and control (44%± 10%) groups (mean difference: 1.9%; 95% confidence interval [CI] =−6.7% to 2.9%). There was no significant difference between pre‐ and posttest scores among groups at one month (Web intervention 48%± 10% vs. control 45%± 10%; mean difference: 3.3%; 95% CI =−8.5% to 2.0%) and six months (Web intervention 51%± 8% vs. control 47%± 9%; mean difference: 3.8%; 95% CI =−8.8% to 1.2%). More than 60% of physicians cited media reports as their primary source of information on bioterrorism and believed that their knowledge of bioterrorism was limited after one month. Conclusions: Providing physicians information on bioterrorism through simulated cases and continuous access to an educational Web site does not increase knowledge of bioterrorism. Physicians are more likely to use media reports for their primary source of information.
TRISS: Does It Get Better than This?
Authors: Gabbe Belinda J. , Cameron Peter A. , Wolfe Rory
Published: January 2008

The Trauma and Injury Severity Scoring (TRISS) system was developed in the 1980s to improve the prediction of patient outcomes following trauma through the use of physiological and anatomical criteria. The TRISS is used for a number of purposes, including quantifying the severity of injury of a patient population, calculating the probability of survival of patients for identification of cases for peer review, and comparing the death or survival rates of different populations/hospitals. Despite the advancements in trauma care, improved statistical techniques, and the identification of numerous limitations of TRISS, it continues to be the most commonly used tool for judging hospital performance and monitoring trauma death rates. This article critically evaluates the development, structure, and practical use of TRISS to determine its value in the current trauma environment. Limitations of TRISS are discussed and suggestions are made for the future development of trauma prediction tools.
Proxy Identification: A Time‐dependent Analysis
Authors: Wright David W. , Lancaster Robert Todd , Ratcliff Jonathan J. , Lowery Douglas W. , Wald Marlena M.
Published: January 2008

Objectives: To describe the availability of next‐of‐kin (NOK) for proxy consent over the 24‐hour time period following presentation of major trauma patients to a Level I trauma center. Methods: The study was conducted by using a prospective, observational study design. Consecutive patients meeting predefined major trauma criteria during a three‐month study period were enrolled and followed until NOK were contacted, or up to 24 hours. Survival analysis was used to determine the probability of NOK contact during the 24‐hour follow‐up period. Results: Three hundred fifty (92%) of 382 subjects had NOK contacted during the follow‐up period. The probabilities (95% confidence intervals [CIs]) of NOK contact at the time of arrival (t= 0) and 2, 4, 6, and 24 hours postpresentation were 0.25 (95% CI = 0.21 to 0.30), 0.68 (95% CI = 0.63 to 0.72), 0.77 (95% CI = 0.73 to 0.82), 0.80 (95% CI = 0.76 to 0.84), and 0.87 (95% CI = 0.84 to 0.90), respectively. The median time to contact was 40 minutes (95% CI = 27 to 54 min). Conclusions: One third of the trauma patients in this study did not have NOK available two hours following arrival in the emergency department. For time‐critical research protocols, the time to NOK contact can significantly impact the ability to ensure prompt enrollment and treatment in clinical trials. Further studies are needed to assess the generalizability and consistency of these data.
Feedback
Authors: Richardson Barbara K.
Published: January 2008

The emergency department provides a rich environment for diverse patient encounters, rapid clinical decision making, and opportunities to hone procedural skills. Well‐prepared faculty can utilize this environment to teach residents and medical students and gain institutional recognition for their incomparable role and teamwork. Giving effective feedback is an essential skill for all teaching faculty. Feedback is ongoing appraisal of performance based on direct observation aimed at changing or sustaining a behavior. Tips from the literature and the author's experience are reviewed to provide formats for feedback, review of objectives, and elements of professionalism and how to deal with poorly performing students. Although the following examples pertain to medical student education, these techniques are applicable to the education of all adult learners, including residents and colleagues. Specific examples of redirection and reflection are offered, and pitfalls are reviewed. Suggestions for streamlining verbal and written feedback and obtaining feedback from others in a fast‐paced environment are given. Ideas for further individual and group faculty development are presented.
Faculty Development
Authors: McLaughlin Steven A.
Published: January 2008

As emergency medicine faculty, we are called upon to be skilled in a great number of different areas. Residency training prepares us to be knowledgeable clinicians, skillful at procedures, good communicators, and effective at multitasking. Rarely, however, does it prepare us as educators or in the nuances of career advancement in an academic environment. Faculty development is a term used to describe both our growth as clinician–educators and navigation of the tenure and promotion process. An important role of medical student educators is to assist in preparing themselves and the faculty to be good teachers. In addition, we all hope to have successful careers as clinician–educators. The goal of this report is 2‐fold: to provide a guide for faculty to advance their skills as educators and to help teaching faculty to advance their academic career. The first section of this report presents an approach to becoming a skilled educator, and the second section focuses on career development as an educator in an academic setting.
Failed Validation of the Argall Weight Formula for Estimating Children's Weight in an Australian Emergency Department
Authors: Nguyen Kevin , Krieser David , Kerr Debra , Jolley Damien , Clooney Megan , Kelly Anne‐Maree
Published: January 2008

BackgroundAn estimate of a child's weight is required for critical interventions, particularly pharmacotherapy. Weight measurement is not always practical, so weight estimation methods are used. Recently, a new weight estimation formula was suggested. The Argall formula estimates weight in kilograms as follows: (age in years + 2) × 3.

ObjectivesTo validate the Argall weight formula.

MethodsThis was a prospective, observational, cohort study conducted in the pediatric emergency department (ED) of Sunshine Hospital. Children aged up to 11 years who presented to the ED during August 18, 2005, to February 25, 2006, were included. Actual weight, height, age, and ethnicity were obtained. Data were analyzed by descriptive statistics (proportion, mean, median, and SD). Agreement between estimated weight using the Argall formula and measured weight is reported by using mean bias, SD, and root mean square error (RMSE) analysis.

ResultsFour hundred ten cases were included, 46% were female, and the median age was 4 years. The Argall formula had a mean bias of −1.66 kg and RMSE of 5.65. Only 37% of Argall estimates were within 10% of the child's actual weight. The formula performed less well in children weighing more than 35 kg but performed better in Asian children than white children.

ConclusionsThe Argall weight estimation formula has poor accuracy for weight estimation in Australian children, in particular those weighing more than 35 kg.
Lethal Mutagenesis of Picornaviruses with N-6-Modified Purine Nucleoside Analogues
Authors: Graci Jason D. , Too Kathleen , Smidansky Eric D. , Edathil Jocelyn P. , Barr Eric W. , Harki Daniel A. , Galarraga Jessica E. , Bollinger J. Martin , Peterson Blake R. , Loakes David , Brown Daniel M. , Cameron Craig E.
Published: January 2008

RNA viruses exhibit extraordinarily high mutation rates during genome replication. Nonnatural ribonucleosides that can increase the mutation rate of RNA viruses by acting as ambiguous substrates during replication have been explored as antiviral agents acting through lethal mutagenesis. We have synthesized novel N-6-substituted purine analogues with ambiguous incorporation characteristics due to tautomerization of the nucleobase. The most potent of these analogues reduced the titer of poliovirus (PV) and coxsackievirus (CVB3) over 1,000-fold during a single passage in HeLa cell culture, with an increase in transition mutation frequency up to 65-fold. Kinetic analysis of incorporation by the PV polymerase indicated that these analogues were templated ambiguously with increased efficiency compared to the known mutagenic nucleoside ribavirin. Notably, these nucleosides were not efficient substrates for cellular ribonucleotide reductase in vitro, suggesting that conversion to the deoxyriboucleoside may be hindered, potentially limiting genetic damage to the host cell. Furthermore, a high-fidelity PV variant (G64S) displayed resistance to the antiviral effect and mutagenic potential of these analogues. These purine nucleoside analogues represent promising lead compounds in the development of clinically useful antiviral therapies based on the strategy of lethal mutagenesis.
Reduced Susceptibility of
Proteus mirabilis
to Triclosan
Authors: Stickler David J. , Jones Gwennan L.
Published: January 2008

Clinical isolates of
Proteus mirabilis
causing catheter encrustation and blockage are susceptible to the biocide triclosan (MICs of 0.2 mg/liter). Studies with laboratory models of the bladder have demonstrated that the inflation of catheter retention balloons with triclosan solutions rather than water results in the diffusion of triclosan from the balloons into the surrounding urine and the inhibition of catheter encrustation by
P. mirabilis
. The aim of this study was to test whether the exposure of
P. mirabilis
to triclosan under laboratory conditions resulted in the selection of strains with reduced susceptibilities to this biocide. Exposure to triclosan in agar was shown to select mutants with MICs elevated from 0.2 mg/liter up to 80 mg/liter. In a selection of 14 of these strains, the decreased susceptibility was found to be stable and not associated with increased resistance to antibiotics. Experiments with the laboratory models demonstrated that inflation of the catheter balloons with triclosan (10 mg/ml) prevented encrustation and blockage by the parent strain
P. mirabilis
B2 (MIC, 0.2 mg/liter) and the mutant strain M48 (MIC, 2.0 mg/liter) but had no effect on crystalline biofilm formation by strain M55 (MIC, 40 mg/liter). These results suggest that, in any clinical trial or subsequent clinical use of the strategy, it will be important to monitor the urinary flora of the catheterized patients for
P. mirabilis
strains with reduced susceptibility to triclosan. The emergence of these strains could undermine the ability of the triclosan strategy to control catheter encrustation.
Determinants of In Vitro Drug Susceptibility Testing of
Plasmodium vivax
Authors: Russell B. , Chalfein F. , Prasetyorini B. , Kenangalem E. , Piera K. , Suwanarusk R. , Brockman A. , Prayoga P. , Sugiarto P. , Cheng Q. , Tjitra E. , Anstey N. M. , Price R. N.
Published: January 2008

In Papua, Indonesia, the antimalarial susceptibility of
Plasmodium vivax
(
n
= 216) and
P. falciparum
(
n
= 277) was assessed using a modified schizont maturation assay for chloroquine, amodiaquine, artesunate, lumefantrine, mefloquine, and piperaquine. The most effective antimalarial against
P. vivax
and
P. falciparum
was artesunate, with geometric mean 50% inhibitory concentrations (IC
50
s) (95% confidence intervals [CI]) of 1.31 nM (1.07 to 1.59) and 0.64 nM (0.53 to 0.79), respectively. In contrast, the geometric mean chloroquine IC
50
for
P. vivax
was 295 nM (227 to 384) compared to only 47.4 nM (42.2 to 53.3) for
P. falciparum
. Two factors were found to significantly influence the in vitro drug response of
P. vivax
: the initial stage of the parasite and the duration of the assay. Isolates of
P. vivax
initially at the trophozoite stage had significantly higher chloroquine IC
50
s (478 nM [95% CI, 316 to 722]) than those initially at the ring stage (84.7 nM [95% CI, 45.7 to 157];
P
< 0.001). Synchronous isolates of
P. vivax
and
P. falciparum
which reached the target of 40% schizonts in the control wells within 30 h had significantly higher geometric mean chloroquine IC
50
s (435 nM [95% CI, 169 to 1,118] and 55.9 nM [95% CI, 48 to 64.9], respectively) than isolates that took more than 30 h (39.9 nM [14.6 to 110.4] and 36.9 nM [31.2 to 43.7];
P
< 0.005). The results demonstrate the marked stage-specific activity of chloroquine with
P. vivax
and suggest that susceptibility to chloroquine may be associated with variable growth rates. These findings have important implications for the phenotypic and downstream genetic characterization of
P. vivax
.
A Class II Histone Deacetylase Acts on Newly Synthesized Histones in
Tetrahymena
Authors: Smith Joshua J. , Torigoe Sharon E. , Maxson Julia , Fish Lisa C. , Wiley Emily A.
Published: January 2008

Newly synthesized histones are acetylated prior to their deposition into nucleosomes. Following nucleosome formation and positioning, they are rapidly deacetylated, an event that coincides with further maturation of the chromatin fiber. The histone deacetylases (HDACs) used for histone deposition and de novo chromatin formation are poorly understood. In the ciliate
Tetrahymena thermophila
, transcription-related deacetylation in the macronucleus is physically separated from deposition-related deacetylation in the micronucleus. This feature was utilized to identify an HDAC named Thd2, a class II HDAC that acts on newly synthesized histones to remove deposition-related acetyl moieties. The
THD2
transcript is alternatively spliced, and the major form contains a putative inositol polyphosphate kinase (IPK) domain similar to Ipk2, an enzyme that promotes chromatin remodeling by SWI/SNF remodeling complexes. Cells lacking Thd2, which retain deposition-related acetyl moieties on new histones, exhibit chromatin and cytological phenotypes indicative of a role for Thd2 in chromatin maturation, including the proteolytic processing of histone H3.
Peroxisome Proliferator-Activated Receptors Mediate Host Cell Proinflammatory Responses toPseudomonas aeruginosaAutoinducer
Authors: Jahoor Aruna , Patel Rashila , Bryan Amanda , Do Catherine , Krier Jay , Watters Chase , Wahli Walter , Li Guigen , Williams Simon C. , Rumbaugh Kendra P.
Published: January 2008

The pathogenic bacteriumPseudomonas aeruginosautilizes the 3-oxododecanoyl homoserine lactone (3OC12-HSL) autoinducer as a signaling molecule to coordinate the expression of virulence genes through quorum sensing. 3OC12-HSL also affects responses in host cells, including the upregulation of genes encoding inflammatory cytokines. This proinflammatory response may exacerbate underlying disease duringP. aeruginosainfections. The specific mechanism(s) through which 3OC12-HSL influences host responses is unclear, and no mammalian receptors for 3OC12-HSL have been identified to date. Here, we report that 3OC12-HSL increases mRNA levels for a common panel of proinflammatory genes in murine fibroblasts and human lung epithelial cells. To identify putative 3OC12-HSL receptors, we examined the expression patterns of a panel of nuclear hormone receptors in these two cell lines and determined that both peroxisome proliferator-activated receptor beta/delta (PPARβ/δ) and PPARγ were expressed. 3OC12-HSL functioned as an agonist of PPARβ/δ transcriptional activity and an antagonist of PPARγ transcriptional activity and inhibited the DNA binding ability of PPARγ. The proinflammatory effect of 3OC12-HSL in lung epithelial cells was blocked by the PPARγ agonist rosiglitazone, suggesting that 3OC12-HSL and rosiglitazone are mutually antagonistic negative and positive regulators of PPARγ activity, respectively. These data identify PPARβ/δ and PPARγ as putative mammalian 3OC12-HSL receptors and suggest that PPARγ agonists may be employed as anti-inflammatory therapeutics forP. aeruginosainfections.
DNA Microarray Analysis of Central Carbohydrate Metabolism: Glycolytic/Gluconeogenic Carbon Switch in the Hyperthermophilic Crenarchaeum
Thermoproteus tenax
Authors: Zaparty Melanie , Zaigler Alexander , Stamme Claudia , Soppa Jörg , Hensel Reinhard , Siebers Bettina
Published: January 2008

In order to unravel the role of regulation on transcript level in central carbohydrate metabolism (CCM) of
Thermoproteus tenax
, a focused DNA microarray was constructed by using 85 open reading frames involved in CCM. A transcriptional analysis comparing heterotrophic growth on glucose versus autotrophic growth on CO
2
-H
2
was performed.
Pseudomonas aeruginosa
AlgR Regulates Type IV Pilus Biosynthesis by Activating Transcription of the
fimU-pilVWXY1Y2E
Operon
Authors: Belete Belen , Lu Haiping , Wozniak Daniel J.
Published: January 2008

The response regulator AlgR is required for
Pseudomonas aeruginosa
type IV pilus-dependent twitching motility, a flagellum-independent mode of solid surface translocation. Prior work showed that AlgR is phosphorylated at aspartate 54, and cells expressing an AlgR variant that cannot undergo phosphorylation (AlgRD54N) lack twitching motility. However, the mechanism by which AlgR controls twitching motility is not completely understood. We hypothesized that AlgR functioned by activating genes within the prepilin
fimU-pilVWXY1Y2E
cluster that are necessary for type IV pilin biogenesis. Reverse transcriptase PCR analysis showed that the
fimU-pilVWXY1Y2E
genes are cotranscribed in an operon, which is under the control of AlgR. This supports prior transcriptional profiling studies of wild-type strains and
algR
mutants. Moreover, expression of the
fimU-pilVWXY1Y2
E operon was reduced in strains expressing AlgRD54N. DNase footprinting and electrophoretic mobility shift assays demonstrate that AlgR but not AlgRD54N bound with high affinity to two sites upstream of the
fimU-pilVWXY1Y2E
operon. Altogether, our findings indicate that AlgR is essential for proper pilin localization and that phosphorylation of AlgR results in direct activation of the
fimU-pilVWXY1Y2E
operon, which is required for the assembly and export of a functional type IV pilus.
Functional Differences between Heme Permeases:
Serratia marcescens
HemTUV Permease Exhibits a Narrower Substrate Specificity (Restricted to Heme) Than the
Escherichia coli
DppABCDF Peptide-Heme Permease
Authors: Létoffé Sylvie , Delepelaire Philippe , Wandersman Cécile
Published: January 2008

Serratia marcescens hemTUV
genes encoding a potential heme permease were cloned in
Escherichia coli
recombinant mutant FB827
dppF
::Km(pAM 238-hasR). This strain, which expresses HasR, a foreign heme outer membrane receptor, is potentially capable of using heme as an iron source. However, this process is invalidated due to a
dppF
::Km mutation which inactivates the Dpp heme/peptide permease responsible for heme, dipeptide, and δ-aminolevulinic (ALA) transport through the
E. coli
inner membrane. We show here that
hemTUV
genes complement the Dpp permease for heme utilization as an iron source and thus are functional in
E. coli
. However,
hemTUV
genes do not complement the Dpp permease for ALA uptake, indicating that the HemTUV permease does not transport ALA. Peptides do not inhibit heme uptake in vivo, indicating that, unlike Dpp permease, HemTUV permease does not transport peptides. HemT, the periplasmic binding protein, binds heme. Heme binding is saturable and not inhibited by peptides that inhibit heme uptake by the Dpp system. Thus, the
S. marcescens
HemTUV permease and, most likely, HemTUV orthologs present in many gram-negative pathogens form a class of heme-specific permeases different from the Dpp peptide/heme permease characterized in
E. coli
.
Genomic Characterization of Mycobacteriophage Giles: Evidence for Phage Acquisition of Host DNA by Illegitimate Recombination
Authors: Morris Peter , Marinelli Laura J. , Jacobs-Sera Deborah , Hendrix Roger W. , Hatfull Graham F.
Published: January 2008

A characteristic feature of bacteriophage genomes is that they are architecturally mosaic, with each individual genome representing a unique assemblage of individual exchangeable modules. Plausible mechanisms for generating mosaicism include homologous recombination at shared boundary sequences of module junctions, illegitimate recombination in a non-sequence-directed process, and site-specific recombination. Analysis of the novel mycobacteriophage Giles genome not only extends our current perspective on bacteriophage genetic diversity, with more than 60% of the genes unrelated to other mycobacteriophages, but offers novel insights into how mosaic genomes are created. In one example, the integration/excision cassette is atypically situated within the structural gene operon and could have moved there either by illegitimate recombination or more plausibly via integrase-mediated site-specific recombination. In a second example, a DNA segment has been recently acquired from the host bacterial chromosome by illegitimate recombination, providing further evidence that phage genomic mosaicism is generated by nontargeted recombination processes.
Identification of Amino Acid Residues within the N-Terminal Domain of EspA That Play a Role in EspA Filament Biogenesis and Function
Authors: Singh Mona P. , Shaw Robert K. , Knutton Stuart , Pallen Mark J. , Crepin Valerie F. , Frankel Gad
Published: January 2008

Enteropathogenic
Escherichia coli
employs a filamentous type III secretion system, made by homopolymerization of the translocator protein EspA. In this study, we have shown that the N-terminal region of EspA has a role in EspA's protein stability, interaction with the CesAB chaperone, and filament biogenesis and function.
CmeR Functions as a Pleiotropic Regulator and Is Required for Optimal Colonization of
Campylobacter jejuni
In Vivo
Authors: Guo Baoqing , Wang Ying , Shi Feng , Barton Yi-Wen , Plummer Paul , Reynolds Donald L. , Nettleton Dan , Grinnage-Pulley Tara , Lin Jun , Zhang Qijing
Published: January 2008

CmeR functions as a transcriptional repressor modulating the expression of the multidrug efflux pump CmeABC in
Campylobacter jejuni
. To determine if CmeR also regulates other genes in
C. jejuni
, we compared the transcriptome of the
cmeR
mutant with that of the wild-type strain using a DNA microarray. This comparison identified 28 genes that showed a ≥2-fold change in expression in the
cmeR
mutant. Independent real-time quantitative reverse transcription-PCR experiments confirmed 27 of the 28 differentially expressed genes. The CmeR-regulated genes encode membrane transporters, proteins involved in C
4
-dicarboxylate transport and utilization, enzymes for biosynthesis of capsular polysaccharide, and hypothetical proteins with unknown functions. Among the genes whose expression was upregulated in the
cmeR
mutant, Cj0561c (encoding a putative periplasmic protein) showed the greatest increase in expression. Subsequent experiments demonstrated that this gene is strongly repressed by CmeR. The presence of the known CmeR-binding site, an inverted repeat of TGTAAT, in the promoter region of Cj0561c suggests that CmeR directly inhibits the transcription of Cj0561c. Similar to expression of
cmeABC
, transcription of Cj0561c is strongly induced by bile compounds, which are normally present in the intestinal tracts of animals. Inactivation of Cj0561c did not affect the susceptibility of
C. jejuni
to antimicrobial compounds in vitro but reduced the fitness of
C. jejuni
in chickens. Loss-of-function mutation of
cmeR
severely reduced the ability of
C. jejuni
to colonize chickens. Together, these findings indicate that CmeR governs the expression of multiple genes with diverse functions and is required for
Campylobacter
adaptation in the chicken host.
SarA ofStaphylococcus aureusBinds to thesarAPromoter To Regulate Gene Expression
Authors: Cheung Ambrose L. , Nishina Koren , Manna Adhar C.
Published: January 2008

The 375-bpsarAopen reading frame is driven by three promoters, P1, P3, and P2. Using gel shift and DNase I footprinting assays, we found that SarA binds to two 26-bp sequences and one 31-bp sequence within the P1 and P3 promoters, respectively. Together with the results of transcription analyses, our data indicate that SarA binds to its own promoter to down-regulatesarAexpression.
C-reactive protein in schoolchildren and its relation to adiposity, physical activity, aerobic fitness and habitual diet
Authors: Thomas N-E , Baker J S , Graham M R , Cooper S-M , Davies B
Published: January 2008

Objective:

To investigate the relation between C-reactive protein (CRP), adiposity, physical activity, aerobic fitness and habitual diet in a cohort of schoolchildren.

Methods:

A cross-sectional study of 164 schoolchildren aged 12–13 years was conducted in two schools. Adiposity was estimated using body mass index and waist circumference. Blood samples were taken after an overnight fast and measured for CRP. Aerobic fitness and habitual physical activity were assessed using the 20 metres multistage fitness test, and a seven-day recall, respectively. A seven-day food diary provided measures of dietary intake.

Results:

To improve the distribution of this variable, CRP levels were logarithmically transformed in all analyses. There was no significant difference in mean CRP concentration between boys (1.07 (1.33) mg/l) and girls (1.24 (1.87) mg/l) (p⩾0.05). Compared to girls, boys reported significantly higher (i) aerobic fitness 59.2 (20.3) shuttles vs 42.9 (15.3) shuttles, (ii) vigorous activity levels per week 92 (123) minutes vs 11.2 (34.6) minutes and (iii) waist circumference 69.8 (1.1) cm vs 65.2 (0.9) cm (p⩽0.05). Among boys and girls, adiposity was significantly associated with log transformed CRP (p⩽0.05). CRP was not significantly related to any other variable.

Conclusion:

Elevated CRP was evident in this cohort; however, whether high CRP levels during childhood and adolescence leads to an increased risk of CVD in later life has not been determined. Adiposity was related to CRP concentration, suggesting that reducing adiposity may be effective in lowering CRP and preventing future cardiovascular events.
Use of DNA hybridization values to construct three-dimensional models of fluorescent pseudomonad relationships
Authors: Hildebrand D. C. , Huisman O. C. , Schroth M. N.
Published: January 2008

Three-dimensional models of the relationships among fluorescent pseudomonads were prepared from appropriately transformed percent DNA homology values. The transformation selected was f(x) = ((1 – HOM/HOM)200, where HOM = fractional DNA homology and 200 is a scaling factor. Model accuracy was quite good as a plot of transformed DNA homology values versus model distances was essentially linear for homology values greater than 30%. The model suggested that bacterial strains within the fluorescent pseudomonads appear to be related in a three-dimensional continuum with no clear and easy "natural" demarcation into groups (i.e., species).
Involvement of outer membrane proteins in freeze–thaw resistance of Escherichia coli
Authors: Calcott Peter H. , Calcott Katherine N.
Published: January 2008

Two families of Escherichia coli mutants with altered outer membrane protein components were examined for sensitivity to freezing and thawing and other stresses. A mutant unable to make the lipoprotein (lpo) was extremely sensitive to freezing and thawing in water or saline and to challenge with detergent, while the mutant unable to make the porin proteins (ompB) was more resistant than the isogenic wild type; strains unable to make the tsx and ompA proteins were slightly more sensitive to the stresses. Similarly, the lpo deficient strain exhibited more and the ompB less wall and membrane damage than the wild-type strains. Little difference in the extent of wall damage, but more membrane damage, was seen for the two tsx and the ompA strains when compared with the wild-type strain. The roles of the specific proteins in determining sensitivity to freeze–thaw are discussed.
Glutamine synthetase from Mycobacterium avium
Authors: Alvarez Maria E. , McCarthy C. M.
Published: January 2008

Mycobacterium avium was previously shown to be dependent upon ammonia or glutamine as a nitrogen source. In an effort to assess the physiology of ammonia assimilation by M. avium, a characterization of its glutamine synthetase was performed. The enzyme from M. avium was purified by streptomycin sulfate treatment, ammonium sulfate precipitation, and affinity chromatography. The enzyme was unusual in that it had a pH optimum of 6.4 and maximum enzyme activity was obtained between 50 and 60 °C as shown by the transferase assay. The glutamine synthetase activity from batch-cultured cells decreased with increasing concentration of ammonium chloride in the range of 0.25–5 μ mol/mL of medium, which demonstrated a response to environmental supply of a nitrogen source. The mycobacterial enzyme was similar to the other bacterial glutamine synthetases in terms of molecular weight and sedimentation coefficient which were 600 000 and 19.5 S, respectively, and enzyme activity was lost by treatment with a glutamate analog, methionine sulfoximine. The isoelectric point was, however, pH 4.5. Treatment of the enzyme with snake venom phosphodiesterase resulted in an increase in specific activity. AMP was released by the phosphodiesterase treatment, thus demonstrating that M. avium glutamine synthetase was regulated by adenylylation modification.
Phenotypic traits of fluorescent pseudomonads causing bacterial blotch of Agaricus bisporus mushrooms and other mushroom-derived fluorescent pseudomonads
Authors: Zarkower P. A. , Wuest P. J. , Royse D. J. , Myers B.
Published: January 2008

Fluorescent pseudomonads isolated from diseased Agaricus bisporus mushrooms (bacterial blotch), internal mushroom stipe tissue, and reference cultures were subjected to an array of determinative tests including a recently described white-line reaction. All isolates recovered from fresh, healthy mushroom tissue proved to be in the range of Pseudomonas putida or P. fluorescens types, producing oxidase and arginine dehydrolase with growth at 4 °C, while failing to cause soft rot of potato tissue or to blotch mushroom tissue, produce pigment on King's medium A, or to grow at 41 °C. Significantly, 68 cultures identified as P. fluorescens belonged to biotype G, 35 having a similar nutritional profile, which suggests a unique identity. Six of eight P. tolaasii reference cultures were pathogens but their placement into a defined biotype is speculative. Dissociative tendencies were commonplace with all isolates. The white-line test was employed with P. tolaasii reference cultures. Those which caused blotch had an R reaction, white-line test. Of 90 isolates from diseased tissue, 76 were indicators (I) and 14 nonreactors (NR). The white-line reaction occurred in King's medium B as described and on three additional substrates. Hundreds of isolates responded as expected with either an I or an R reaction even though stored for up to 2 years. Reliable assessment of P. tolaasii pathogenicity using excised pileus tissue required three replicates read following 24 h incubation.
Effects of pretreatments with sulfhydryls and alkylating agents on spheroplast formation from Schwanniomyces species
Authors: Dowhanick T. M. , Panchal C. J. , Stewart G. G.
Published: January 2008

Pretreatment of cells with β-mercaptoethanol, dithiothreitol, or cysteine increased the rate of spheroplast formation at all stages of growth in Schwanniomyces castellii and S. occidentalis, but had little effect on final yields of spheroplasts when compared with controls. Pretreatment with iodoacetate and cystine resulted in decreased rates of formation and lower yields of spheroplasts at all stages of growth for both species. The enhanced rates of spheroplast formation in the presence of the sulfhydryl compounds were more pronounced when the experimental cells were derived from early or late stationary phase cultures, whereas the inhibitory effects of cystine and iodoacetate were not associated with the growth phase. In agreement with extant data on other yeast genera, sulfhydryl compounds increased the susceptibility of the yeast cell wall to degradative enzymes, whilst alkylating agents decreased susceptibility of cell walls to these enzymes.
Interlayer grafting of glycidol (2,3-epoxy-1-propanol) on kaolinite
Authors: Letaief S , Detellier C
Published: January 2008

An organic–inorganic nanohybrid material was prepared by grafting glycidol (2,3-epoxy-1-propanol) on the interlayer aluminol groups of kaolinite (K) using DMSO–K precursor as a starting material. The results of the physicochemical characterization of the synthesized materials (XRD, FTIR, DTA–TG, 13C and 29Si CP/MAS NMR) confirm that the grafting reaction of glycidol involved the opening of the oxirane ring. The resulting nanohybrid material is similar to the one obtained by the interlayer grafting of glycerol (M. Janek, K. Emmerich, S. Heissler, and R. Nüesch. Chem. Mater. 19, 684, (2007)). Approximately, one glycidol moiety is grafted on each structural unit of kaolinite to afford a material with the chemical composition Al2Si2O5(OH)4[C3H6O2]0.9.Key words: clays, clay minerals, kaolinite, intercalation, grafting, nanohybrid materials, DMSO, glycidol, glycerol, oxirane.