bluuebunny/crossref_metadata_2025 huggingface dataset:
Behavior of the Electrocardiographic T Peak to End Interval in Childhood
Authors: Benatar Abraham , Carbonez Karlien
Published: January 2010

Background: The T‐wave peak to T‐wave end (TpTe) interval reflects spatial and transmural dispersion in repolarization and serves as an arrhythmogenic index. Normal TpTe interval data in children are lacking. We evaluated the effects of age, gender, heart rate, leads (II and V5) on TpTe and T‐wave voltage.

Methods: Four hundred healthy children (age 4 days to 16.7 years) were enrolled. From a resting 12‐lead digital ECG, TpTe, RR, QT, JT intervals, and T amplitude were measured (leads II and V5). Bazett and Fridericia formulas were applied to TpTe for heart rate correction and TpTe/QT and TpTe/JT were calculated. Descriptive and analytical statistics were applied, significance level set at P ≤ 0.05.

Results: TpTe in leads II and V5 correlate well. Contrary to adults, no gender differences in TpTe were observed in childhood. TpTe lengthens with increasing age, and is inversely related to heart rate. TpTe 98th percentile is 85 msec in first 5 years, increasing to 92 msec in adolescence. TpTe Fridericia is a good correction formula in childhood; TpTe Bazett overcorrects in the younger age. TpTe/QT and TpTe/JT are longer in younger subjects due to greater QT shortening than the TpTe interval at higher heart rates.

Conclusions: In children, TpTe in lead II and V5 correlate well. The TpTe interval lengthens with advancing age as heart rate diminishes. TpTe Fridericia is a good correction formula in children. Younger subjects have higher TpTe/QT and TpTe/JT indices compared to older children. T‐wave voltage increases with age, tallest in the 5–10‐year‐age group particularly in V5.

Ann Noninvasive Electrocardiol 2010;15(1):11–16
Abnormal P‐Wave Morphology Is a Predictor of Atrial Fibrillation Development and Cardiac Death in MADIT II Patients
Authors: Holmqvist Fredrik , Platonov Pyotr G. , McNitt Scott , Polonsky Slava , Carlson Jonas , Zareba Wojciech , Moss Arthur J. ,   for the MADIT II Investigators
Published: January 2010

Background: Several ECG‐based approaches have been shown to add value when risk‐stratifying patients with congestive heart failure, but little attention has been paid to the prognostic value of abnormal atrial depolarization in this context. The aim of this study was to noninvasively analyze the atrial depolarization phase to identify markers associated with increased risk of mortality, deterioration of heart failure, and development of atrial fibrillation (AF) in a high‐risk population with advanced congestive heart failure and a history of acute myocardial infarction.

Methods: Patients included in the Multicenter Automatic Defibrillator Implantation Trial II (MADIT II) with sinus rhythm at baseline were studied (n = 802). Unfiltered and band‐pass filtered signal‐averaged P waves were analyzed to determine orthogonal P‐wave morphology (prespecified types 1, 2, and 3/atypical), P‐wave duration, and RMS20. The association between P‐wave parameters and data on the clinical course and cardiac events during a mean follow‐up of 20 months was analyzed.

Results: P‐wave duration was 139 ± 23 ms and the RMS20 was 1.9 ± 1.1 μV. None of these parameters was significantly associated with poor cardiac outcome or AF development. After adjustment for clinical covariates, abnormal P‐wave morphology was found to be independently predictive of nonsudden cardiac death (HR 2.66; 95% CI 1.41–5.04, P = 0.0027) and AF development (HR 1.75; 95% CI 1.10–2.79, P = 0.019).

Conclusion: Abnormalities in P‐wave morphology recorded from orthogonal leads in surface ECG are independently predictive of increased risk of nonsudden cardiac death and AF development in MADIT II patients.

Ann Noninvasive Electrocardiol 2010;15(1):63–72
Differences in twitch potentiation between voluntary and stimulated quadriceps contractions of equal intensity
Authors: Jubeau M. , Gondin J. , Martin A. , Van Hoecke J. , Maffiuletti N. A.
Published: January 2010

This study compared the extent of twitch and M‐wave potentiation (POT) between voluntary and stimulated quadriceps contractions performed at the same intensity. Sixteen healthy men completed 10‐s isometric knee extensions at 40% of the maximal voluntary contraction torque under electrical stimulation and voluntary conditions. Single stimuli were delivered to the femoral nerve to evoke twitches before (PRE) and from 3 to 600 s after the end of each conditioning contraction. Changes in twitch contractile properties and M‐wave characteristics were compared between the conditions. The extent of twitch peak torque POT was smaller for the stimulated (122±20% of PRE) than for the voluntary condition (133±20% of PRE). The magnitude of POT for the maximal rate of twitch torque development was also smaller for the stimulated trial. Rectus femoris M‐wave amplitude was potentiated by the voluntary but not by the stimulated contraction. It was concluded that stimulated contractions resulted in smaller twitch and M‐wave POT than voluntary contractions, despite equivalent torque output and duration. The spatially and temporally fixed recruitment of motor units with electrical stimulation and therefore the lower number of activated motor units compared with voluntary actions of equal intensity could explain the present findings.
Morphological changes in hind limb muscles elicited by adjuvant‐induced arthritis of the rat knee
Authors: Ozawa J. , Kurose T. , Kawamata S. , Yamaoka K.
Published: January 2010

We investigated qualitative and quantitative changes in rat hind limb muscles caused by complete Freund's adjuvant (CFA)‐induced knee joint pain. One week after CFA injection, muscle atrophy was induced only on the CFA‐injected side. Wet weight of the rectus femoris (RF) and soleus (SOL) muscles were significantly decreased by 20% and 19%, respectively. The reduction in cross‐sectional areas by CFA was similar for fast and slow muscle fibers in the RF (10% vs 15%, respectively) and SOL muscles (16% vs 16%, respectively). At the light microscopic level, pathological changes were not found in the RF muscles on both sides, although the infiltration of mononuclear cells and muscle regeneration were found in the SOL muscles on CFA‐injected and contralateral control sides. On the other hand, electron microscopy revealed degenerative changes in the RF and SOL muscles on the CFA‐injected side. Interestingly, sarcomere hypercontraction, indicating overexercise, was observed to a limited extent in the SOL muscles on the control side. In conclusions, knee joint pain can trigger the rapid development of muscle atrophy with degenerative changes not only in thigh but also calf muscles. This indicates that early interventions to inhibit joint pain or inflammation may prevent muscle atrophy.
Exercise capacity in Dutch children: new reference values for the Bruce treadmill protocol
Authors: Van Der Cammen‐van Zijp M. H. M. , Van Den Berg‐Emons R. J. G. , Willemsen S. P. , Stam H. J. , Tibboel D. , IJsselstijn H.
Published: January 2010

The Bruce treadmill protocol is suitable for children 4 years of age and older. Dutch reference values were established in 1987. We considered that children's exercise capacity has deteriorated due to changes in physical activity patterns and eating habits. We determined new reference values and evaluated determinants of exercise capacity. Healthy Dutch children (n=267) aged 6–13 years participated in this cross‐sectional observational study. The maximal endurance time on the treadmill was the criterion of exercise capacity. Furthermore, we obtained data on anthropometry, smoking habits, socioeconomic status, ethnicity, sports participation, and school transport habits. The maximal endurance time for children aged up till 10 was lower (up to 1.6 and 1.4 min in girls and boys, respectively) than previously published. Body mass index was negatively, and intense sports participation was positively associated with endurance time (β=−0.412 and 0.789, respectively; P<0.001). In conclusion, exercise capacity seems to have deteriorated in Dutch children aged up till 10 years whereas the values from the older children are remarkably similar to those from the previous study.
Do PPARGC1A and PPARα polymorphisms influence sprint or endurance phenotypes?
Authors: Eynon N. , Meckel Y. , Sagiv M. , Yamin C. , Amir R. , Sagiv M. , Goldhammer E. , Duarte J. A. , Oliveira J.
Published: January 2010

Functional Gly482Ser (rs8192678) and G/C (rs4253778) polymorphisms in the Peroxisome proliferator‐activated receptor γ coactivator1 (PPARGC1A) and Peroxisome proliferator‐activated receptor α (PPARα) genes, respectively, have been associated with mRNA and protein activity. The aim of this study was to determine their frequency distribution among 155 Israeli athletes (endurance athletes and sprinters) and 240 healthy controls. Results showed that there was a significant difference in PPARGC1A Ser482Gly polymorphism genotype frequencies between endurance athletes and sprinters (P=0.005) as well as between endurance athletes and controls (P=0.0003). However, the sprinters' genotype and allele frequencies were similar to that of the control group. A significantly lower proportion of PPARGC1A Ser482 allele (0.25) was noted for the endurance athletes compared with controls (0.43, P=0.0001). Endurance athletes showed a trend of a higher yet a not significant proportion of the PPARα GG genotype compared with sprinters (P=0.051). As we compared between the subgroups of top‐level endurance athletes and top‐level sprinters, as well as between those of top‐level and national‐level endurance athletes, we reached more prominent results. In conclusion, our data indicate that a lower frequency of the Ser482 allele and possibly a higher frequency of the GG genotype are associated with increased endurance performance ability.
Facts, noise and wishful thinking: muscle protein turnover in aging and human disuse atrophy
Authors: Rennie M. J. , Selby A. , Atherton P. , Smith K. , Kumar V. , Glover E. L. , Philips S. M.
Published: January 2010

Surprisingly little is known about the mechanisms of muscle atrophy with aging and disuse in human beings, in contrast to rodents, from which much has been extrapolated to explain the human condition. However, this extrapolation is likely unwarranted because the time course, extent of wasting, muscle fiber involvement and alterations of muscle protein turnover are all quite different in rodent and human muscle. Furthermore, there is little evidence that static indices of protein turnover represent dynamic changes and may be misleading. With disuse there are reductions in the rate of muscle protein synthesis (MPS) large enough to explain the atrophic loss of muscle protein without a concomitant increase in proteolysis. In aging, there is no evidence that there are marked alterations in basal muscle protein turnover in healthy individuals but instead the ability to maintain muscle after feeding is compromised. This anabolic resistance is evident with physical inactivity, which exacerbates the inability to maintain muscle mass with aging. The main conclusion of this review is that in uncomplicated, non‐inflammatory disuse atrophy, the facilitative change causing loss of muscle mass is a depression of MPS, exacerbated by anabolic resistance during feeding, with possible adaptive depressions, rather than increases, of muscle proteolysis.
First year growth among very low birth weight infants
Authors: Westerberg Ane C. , Henriksen Christine , Ellingvåg Asta , Veierød Marit B. , Júlíusson Pétur B. , Nakstad Britt , Aurvåg Anne K. , Rønnestad Arild , Grønn Morten , Iversen Per O. , Drevon Christian A.
Published: January 2010

Aim:  The aim of this study was to describe first‐year growth among very low birth weight infants and the effect of growth restriction at hospital discharge on first year growth.

Method:  Anthropometric measures and background information for 118 very low birth weight infants were collected from medical records. Z‐scores were calculated based on recent Norwegian growth references.

Results:  Significant catch‐up growth for weight and length was observed during the first year with mean z‐score change (SD) of 0.40 (1.05) and 1.01 (1.25) respectively. However, the very low birth weight infants remained lighter and shorter than full‐term peers until 12 months corrected age with mean z‐score of −0.93 (1.09) and −0.48 (1.06) respectively. Head circumference followed a normal growth pattern after 2 months. Infants discharged from hospital as growth restricted had increased catch‐up in weight and length, but remained smaller than infants not subjected to early growth restriction and full‐term peers. Multiple regression showed that weight below the 10th percentile at discharge is important for weight and length during the first year of life.

Conclusion:  Very low birth weight infants showed catch‐up growth during the first year, but their weight and length remained less than full‐term peers. Growth deficiencies were more pronounced among infants subjected to early growth restriction, despite increased catch‐up growth.
Sensitivity of Solute Advective Travel Time to Porosities of Hydrogeologic Units
Authors: Zhu Jianting , Pohlmann Karl F. , Chapman Jenny B. , Russell Charles E. , Carroll Rosemary W. H. , Shafer David S.
Published: January 2010

An integral approach is proposed to quantify uncertainty and sensitivity of advective travel time to the effective porosities of hydrogeologic units (HGUs) along groundwater flow paths. The approach is applicable in situations where a groundwater flow model exists, but a full solute transport model is not available. The approach can be used to: (1) determine HGUs whose porosities are influential to the solute advective travel time; and (2) apportion uncertainties of solute advective travel times to the uncertainty contributions from individual HGU porosities. A simple one‐dimensional steady‐state flow example is used to illustrate the approach. Advective travel times of solutes are obtained based on the one‐dimensional steady‐state flow results in conjunction with the HGU porosities. The approach can be easily applicable to more complex multi‐dimensional cases where advective solute travel time can be calculated based on simulated flow results from groundwater flow models. This approach is particularly valuable for optimizing limited resources when designing field characterization programs for uncertainty reduction by identifying HGUs that contribute most to the estimation uncertainty of advective travel times of solutes.
Tumour necrosis factor‐like weak inducer of apoptosis (TWEAK) and its receptor Fn14 during cardiac remodelling in rats
Authors: Mustonen E. , Säkkinen H. , Tokola H. , Isopoussu E. , Aro J. , Leskinen H. , Ruskoaho H. , Rysä J.
Published: January 2010

Aim:  Accumulating evidence supports the concept that proinflammatory cytokines play an essential role in the failing heart. We examined the concomitant tumour necrosis factor‐like weak inducer of apoptosis (TWEAK)/Fn14 expression in myocytes in vitro as well as in vivo in cardiac remodelling.

Methods:  We assessed TWEAK and its receptor Fn14 expression in response to angiotensin (Ang) II, myocardial infarction (MI) as well as to local adenovirus‐mediated p38 gene transfer in vivo. The effect of various hypertrophic factors and mechanical stretch was studied in neonatal rat ventricular myocyte cell culture.

Results:  Ang II increased Fn14 levels from 6 h to 2 weeks, the greatest increase in mRNA levels being observed at 6 h (6.3‐fold, P < 0.001) and protein levels at 12 h (4.9‐fold, P < 0.01). TWEAK mRNA and protein levels remained almost unchanged during Ang II infusion. Likewise, a rapid and sustained elevation of Fn14 mRNA and protein levels in the left ventricle was observed after experimental MI. Moreover, local p38 gene transfer increased Fn14 mRNA and protein but not TWEAK levels. Fn14 immunoreactive cells were mainly proliferating non‐myocytes in the inflammation area while TWEAK immunoreactivity localized to cardiomyocytes and endothelial cells of the coronary arteries. Hypertrophic agonists and lipopolysaccharide increased Fn14 but not TWEAK gene expression in neonatal rat myocytes, while mechanical stretch upregulated Fn14 and downregulated TWEAK gene expression.

Conclusions:  In conclusion, the cardiac TWEAK/Fn14 pathway is modified in response to myocardial injury, inflammation and pressure overload. Furthermore, our findings underscore the importance of Fn14 as a mediator of TWEAK/Fn14 signalling in the heart and a potential target for therapeutic interventions.
Effect of reduced total blood volume on left ventricular volumes and kinetics in type 2 diabetes
Authors: Lalande S. , Hofman P. L. , Baldi J. C.
Published: January 2010

Aim:  Although impaired left ventricular (LV) diastolic function is commonly observed in patients with type 2 diabetes, it remains unclear whether the impairment is caused by altered LV relaxation or changes in LV preload. The purpose of this study was to examine the influence of LV function and LV loading conditions on stroke volume in men with type 2 diabetes.

Methods:  Cardiac magnetic resonance imaging scans were performed in eight men with type 2 diabetes and 11 non‐diabetic men matched for age, weight and physical activity level. Total blood volume was determined with the Evans blue dye dilution technique.

Results:  End‐diastolic volume (EDV), the ratio of peak early to late mitral inflow velocity (E/A) and stroke volume were lower in men with type 2 diabetes than in non‐diabetic individuals. Peak filling rate and peak ejection rate were not different between diabetic and non‐diabetic individuals; however, men with type 2 diabetes had proportionally longer systolic duration than non‐diabetic individuals. Heart rate was higher and total blood volume was lower in men with type 2 diabetes. The lower total blood volume was correlated with a lower EDV in men with type 2 diabetes.

Conclusions:  Men with type 2 diabetes have an altered cardiac cycle and lower end‐diastolic and stroke volume. A lower total blood volume and higher heart rate in men with type 2 diabetes suggest that changes in LV preload, independent of changes in LV relaxation or contractility, influence LV diastolic filling and stroke volume in this population.
Serological prevalence study of exposure of cats and dogs in Launceston, Tasmania, Australia to spotted fever group rickettsiae
Authors: Izzard L , Cox E , Stenos J , Waterston M , Fenwick S , Graves S
Published: January 2010

A sero‐epidemiological study of cats and dogs in the Launceston area of Tasmania, Australia was undertaken to determine the prevalence of antibodies to spotted fever group (SFG) rickettsiae. Results showed that 59% of cats and 57% of dogs were positive for antibodies, but there was no correlation between the animal's health and seropositivity at the time of testing, suggesting that rickettsial exposure is unrelated to ill‐health in these two species of domestic animals.
Haemolytic anaemia in cattle in NSW associated with Theileria infections
Authors: Izzo MM , Poe I , Horadagoda N , De Vos AJ , House JK
Published: January 2010

Several outbreaks of anaemia, jaundice, abortion and mortality in cattle in New South Wales were attributed to the intracellular parasite, Theileria buffeli. Disease occurred predominantly in periparturient animals that had been moved from inland to coastal areas. Diagnosis was made via exclusion of other causes of haemolytic anaemia and observation of the parasite in blood smears. Treatments included both registered and non‐registered products. There is a possibility of a new strain of Theileria sp. in Australia and the possible vectors encountered in NSW are discussed.
Best foot forward or best for last in a sequential auction?
Authors: Chakraborty Archishman , Gupta Nandini , Harbaugh Rick
Published: January 2010

Should a seller with private information sell the best or worst goods first? Considering the sequential auction of two stochastically equivalent goods, we find that the seller has an incentive to impress buyers by selling the better good first because the seller's sequencing strategy endogenously generates correlation in the values of the goods across periods. When this impression effect is strong enough, selling the better good first is the unique pure‐strategy equilibrium. By credibly revealing to all buyers the seller's ranking of the goods, an equilibrium strategy of sequencing the goods reduces buyer information rents and increases expected revenues in accordance with the linkage principle.
National versus international mergers in unionized oligopoly
Authors: Lommerud Kjell Erik , Straume Odd Rune , Sørgard Lars
Published: January 2010

We analyze how the presence of trade unions affects the pattern of mergers in an international oligopoly and the welfare implications thereof. We find that wages for the merger participants are always lower when they merge internationally, rather than nationally. Using a model of endogenous merger formation, we find that the firms will merge internationally in equilibrium. There are more international mergers than socially preferred, unless products are close substitutes. A “national champion” policy of promoting domestic mergers rather than international ones is nevertheless never optimal.
Coordinating on lower prices: pharmaceutical pricing under political pressure
Authors: Ellison Sara Fisher , Wolfram Catherine
Published: January 2010

We investigate the effects of political activity on pharmaceutical prices, focusing on the health care reform period in the early 1990s. We characterize firms based on their vulnerability to future price regulation and find that the more vulnerable firms were more likely to take various actions to forestall regulation, most notably coordinating on a specific percentage price increase during 1993. Since moderating price increases could have averted regulation, the coordination appears to be the industry's response to a collective action problem.
Current insights in polymyositis and dermatomyositis
Authors: Kohsaka Hitoshi
Published: January 2010

Polymyositis (PM) and dermatomyositis (DM) are characterized by immune‐mediated muscle damage. Early immunohistochemical studies of PM and DM muscle biopsy samples suggested that PM is mediated by cytotoxic CD8 T lymphocytes, whereas DM is a vasculopathy mediated by antibodies and complement deposition to the intramuscular microvessels. This classic view is now challenged by recent advances in immunology and molecular biology, as well as by clinical observation of the two diseases. Clonal expansion of cytotoxic CD8 T cells was found in the affected muscles and in peripheral blood from PM and DM patients. Autoantigens recognized by these clones are yet to be identified. Patient sera contain various autoantibodies. Although they are not directed to endothelial antigens, detection of specific antibodies helps when classifying the patients. Infiltrating cells, as well as muscle cells, produce cytokines and chemokines that could potentiate inflammation. Myofibers overexpress major histocompatibility complex class I and class II molecules that render themselves vulnerable to immune attacks while they also express molecules that protect themselves from apoptotic cell death. Corticosteroid administration is still a gold standard for PM/DM treatment. A major life‐threatening complication is an interstitial lung disease, the acute form of which should not be treated with corticosteroids alone. Future studies should be carried out to further elucidate their ethiopathology and to develop more effective and specific treatment. (Clin. Exp. Neuroimmunol. doi: 10.1111/j.1759‐1961.2009.00002.x, January 2010)
Quantification of myoglobin deoxygenation and intracellular partial pressure of O2 during muscle contraction during haemoglobin‐free medium perfusion
Authors: Takakura Hisashi , Masuda Kazumi , Hashimoto Takeshi , Iwase Satoshi , Jue Thomas
Published: January 2010

Although the O2 gradient regulates O2 flux from the capillary into the myocyte to meet the energy demands of contracting muscle, intracellular O2 dynamics during muscle contraction remain unclear. Our hindlimb perfusion model allows the determination of intracellular myoglobin (Mb) saturation (

) and intracellular oxygen tension of myoglobin (

) in contracting muscle using near infrared spectroscopy (NIRS). The hindlimb of male Wistar rats was perfused from the abdominal aorta with a well‐oxygenated haemoglobin‐free Krebs–Henseleit buffer. The deoxygenated Mb (Δ[deoxy‐Mb]) signal was monitored by NIRS. Based on the value of Δ[deoxy‐Mb], 
 and 
 were calculated, and the time course was evaluated by an exponential function model. Both 
 and 
 started to decrease immediately after the onset of contraction. The steady‐state values of 
 and 
 progressively decreased with relative work intensity or muscle oxygen consumption. At the maximal twitch rate, 
 and 
 were 49% and 2.4 mmHg, respectively. Moreover, the rate of release of O2 from Mb at the onset of contraction increased with muscle oxygen consumption. These results suggest that at the onset of muscle contraction, Mb supplies O2 during the steep decline in 
, which expands the O2 gradient to increase the O2 flux to meet the increased energy demands.
Interdependence of optimum exposure dose regimes and the kinetics of resist dissolution for electron beam nanolithography of polymethylmethacrylate
Authors: Mohammad M. A. , Fito T. , Chen J. , Aktary M. , Stepanova M. , Dew S. K.
Published: January 2010

The authors report a systematic experimental study of dense nanostructures in polymethylmethacrylate (PMMA) created by low-energy electron beam lithography (EBL) with varying duration and temperature of the resist dissolution. They observe that decreasing the development temperature not only yields the widest favorable exposure dose regimes but also requires highest exposure doses to fabricate dense nanopatterns. They interpret the observed interdependence of the exposure doses and the development temperatures in terms of a simple kinetic model describing the diffusion mobility of fragments in exposed PMMA during dissolution and discuss the corresponding molecular mechanisms that determine the resolution and sensitivity of EBL nanofabrication.
Supersweet: This Is Your Taste Buds on Dope
Authors: Buettner Christoph
Published: January 2010

Endocannabinoid signaling within taste buds enhances sweet-taste perception.
Staphylococcal Cassette Chromosome
mec
-Like Element in
Macrococcus caseolyticus
Authors: Tsubakishita Sae , Kuwahara-Arai Kyoko , Baba Tadashi , Hiramatsu Keiichi
Published: January 2010

Macrococcus
is a bacterial genus that is closely related to
Staphylococcus
, which typically is isolated from animal skin and products. The genome analysis of multidrug-resistant
Macrococcus caseolyticus
strain JCSC5402, isolated from chicken, previously led to the identification of plasmid pMCCL2, which carries a transposon containing an unusual form of the
Macrococcus mec
gene complex (

mecA
m

-

mecR1
m

-

mecI
m

-

blaZ
m

). In
M. caseolyticus
strain JCSC7096, this
mec
transposon containing the
mec
gene complex (designated Tn
6045
in this study) was found integrated downstream of
orfX
on the chromosome. Tn
6045
of JCSC7096 was bracketed by the direct repeat sequences (DR) specifically recognized by cassette chromosome recombinase (CCR). A non-
mecA
-containing staphylococcal cassette chromosome (SCC) element, designated SCC
7096
, was integrated next to the
mec
transposon and separated from the latter by a DR. Nested PCR experiments showed that the
mec
transposon not only was excised singly but also coexcised with SCC
7096
from the chromosome at the DRs. The coexcised elements formed the extrachromosomal closed circular DNA of the SCC
mec
-like element. SCC
mec
is known to be the mobile element conveying methicillin (meticillin) resistance in staphylococci. However, its origin has been unknown. Our observation revealed a potential mechanism of the generation of a new SCC
mec
-like element in
M. caseolyticus
, a commensal bacterium of food animals.
Epidemiology of Invasive Meningococcal Disease with Decreased Susceptibility to Penicillin in Ontario, Canada, 2000 to 2006
Authors: Brown Elizabeth M. , Fisman David N. , Drews Steven J. , Dolman Sharon , Rawte Prasad , Brown Shirley , Jamieson Frances
Published: January 2010

Neisseria meningitidis
has been relatively slow to acquire resistance to penicillin. We previously reported an increase in the incidence of invasive meningococcal disease (IMD) strains with decreased susceptibility to penicillin (DSP) in Ontario. Our objectives were to evaluate trends in IMD with DSP, to identify case-level predictors of IMD with DSP, and to evaluate the relationship among DSP, bacterial phenotype, and the likelihood of a fatal outcome. All IMD isolates received in Ontario between 2000 and 2006 were submitted to the Public Health Laboratories, Toronto, for confirmation of the species, serogroup determination, and susceptibility testing. Isolates were considered to be IMD strains with DSP if the penicillin MIC was ≥0.125 μg/ml. Temporal trends were evaluated using multivariable Poisson regression models. Correlates of diminished susceptibility and fatal outcome were evaluated with multivariable logistic regression models. The overall rate of IMD caused by strains with DSP in Ontario was approximately 1.20 cases per million population annually (95% confidence interval [95% CI], 0.99 to 1.46). Seventy-nine strains (21.7%) were IMD strains with DSP. There was no year-to-year trend in the incidence of IMD with DSP. IMD with DSP was strongly associated with strains of serogroups Y (odds ratio [OR], 6.3; 95% CI, 3.6 to 11.1) and W-135 (OR, 8.2; 95% CI, 4.0 to 16.7). Infection with serogroup B or C strains was associated with a marked increase in the risk of mortality (OR, 3.07; 95% CI, 1.39 to 6.75); however, no association between IMD with DSP and mortality was observed. In contrast to trends of the 1990s, the incidence of IMD with DSP was stable in Ontario between 2000 and 2006. In Ontario, the serogroup rather than the penicillin MIC is the microbiological parameter most predictive of mortality.
Spread of OXA-48-Encoding Plasmid in Turkey and Beyond
Authors: Carrër Amélie , Poirel Laurent , Yilmaz Mesut , Akan Özay Arikan , Feriha Cilli , Cuzon Gaëlle , Matar Ghassan , Honderlick Patrick , Nordmann Patrice
Published: January 2010

Eighteen carbapenem-resistant, OXA-48-positive enterobacterial isolates recovered from Turkey, Lebanon, Egypt, France, and Belgium were analyzed. In most isolates, similar 70-kb plasmids carrying the carbapenemase gene
bla
OXA-48
were identified. That gene was located within either transposon Tn
1999
or transposon Tn
1999.2
, which was always inserted within the same gene. This work highlights the current plasmid-mediated dissemination of the OXA-48 carbapenemase worldwide.
New Susceptibility Breakpoints for First-Line Antituberculosis Drugs Based on Antimicrobial Pharmacokinetic/Pharmacodynamic Science and Population Pharmacokinetic Variability
Authors: Gumbo Tawanda
Published: January 2010

Arguably, one of the most common and consequential laboratory tests performed in the world is
Mycobacterium tuberculosis
susceptibility testing.
M. tuberculosis
resistance is defined by growth of ≥1% of a bacillary inoculum on the critical concentration of an antibiotic. The critical concentration was chosen based on inhibition of ≥95% of wild-type isolates. The critical concentration of isoniazid is either 0.2 or 1.0 mg/liter, that of rifampin is 1.0 mg/liter, that of pyrazinamide is 100 mg/liter, that of ethambutol is 5.0 mg/liter, and that of fluoroquinolones is 1.0 mg/liter. However, the relevance of these concentrations to microbiologic and clinical outcomes is unclear. Critical concentrations were identified using the ability to achieve the antibiotic area under the concentration-time curve/MIC ratio associated with ≥90% of maximal kill (EC
90
) of
M. tuberculosis
in ≥90% of patients. Population pharmacokinetic parameters and their variability encountered in tuberculosis patients were utilized in Monte Carlo simulations to determine the probability that particular daily doses of the drugs would achieve or exceed the EC
90
in the epithelial lining fluid of 10,000 tuberculosis patients. Failure to achieve EC
90
in ≥90% of patients at a particular MIC was defined as drug resistance. The critical concentrations of moxifloxacin and ethambutol remained unchanged, but a critical concentration of 50 mg/liter was identified for pyrazinamide, 0.0312 mg/liter and 0.125 mg/liter were defined for low- and high-level isoniazid resistance, respectively, and 0.0625 mg/liter was defined for rifampin. Thus, current critical concentrations of first-line antituberculosis drugs are overoptimistic and should be set lower. With the proposed breakpoints, the rates of multidrug-resistant tuberculosis could become 4-fold higher than currently assumed.
Genetic Dissection of Azole Resistance Mechanisms in
Candida albicans
and Their Validation in a Mouse Model of Disseminated Infection
Authors: MacCallum Donna M. , Coste Alix , Ischer Françoise , Jacobsen Mette D. , Odds Frank C. , Sanglard Dominique
Published: January 2010

Principal mechanisms of resistance to azole antifungals include the upregulation of multidrug transporters and the modification of the target enzyme, a cytochrome P450 (Erg11) involved in the 14α-demethylation of ergosterol. These mechanisms are often combined in azole-resistant
Candida albicans
isolates recovered from patients. However, the precise contributions of individual mechanisms to
C. albicans
resistance to specific azoles have been difficult to establish because of the technical difficulties in the genetic manipulation of this diploid species. Recent advances have made genetic manipulations easier, and we therefore undertook the genetic dissection of resistance mechanisms in an azole-resistant clinical isolate. This isolate (DSY296) upregulates the multidrug transporter genes
CDR1
and
CDR2
and has acquired a G464S substitution in both
ERG11
alleles. In DSY296, inactivation of
TAC1
, a transcription factor containing a gain-of-function mutation, followed by sequential replacement of
ERG11
mutant alleles with wild-type alleles, restored azole susceptibility to the levels measured for a parent azole-susceptible isolate (DSY294). These sequential genetic manipulations not only demonstrated that these two resistance mechanisms were those responsible for the development of resistance in DSY296 but also indicated that the quantitative level of resistance as measured
in vitro
by MIC determinations was a function of the number of genetic resistance mechanisms operating in any strain. The engineered strains were also tested for their responses to fluconazole treatment in a novel 3-day model of invasive
C. albicans
infection of mice. Fifty percent effective doses (ED
50
s) of fluconazole were highest for DSY296 and decreased proportionally with the sequential removal of each resistance mechanism. However, while the fold differences in ED
50
were proportional to the fold differences in MICs, their magnitude was lower than that measured
in vitro
and depended on the specific resistance mechanism operating.
Revisiting with a Relative-Density Calibration Approach the Determination of Growth Rates of Microorganisms by Use of Optical Density Data from Liquid Cultures
Authors: Lin Hsiu-Li , Lin Chien-Chung , Lin Yi-Jen , Lin Hsiu-Chen , Shih Chwen-Ming , Chen Chi-Rong , Huang Rong-Nan , Kuo Tai-Chih
Published: January 2010

To solve the problems of measuring the growth rates of microorganisms from optical density (OD)-growth time plots, we used relative-density (RD) plots. The relationship of OD and RD was built from the diluted grown cultures. This method was satisfactorily applied to study the growth of
Escherichia coli
and the cyanobacterium
Anabaena spiroides
.
Biofilm Formation by and Multicellular Behavior of
Escherichia coli
O55:H7, an Atypical Enteropathogenic Strain
Authors: Weiss-Muszkat Michal , Shakh Dana , Zhou Yizhou , Pinto Riky , Belausov Eddy , Chapman Matthew R. , Sela Shlomo
Published: January 2010

Enteropathogenic
Escherichia coli
(EPEC) is an important causal agent of diarrheal illness throughout the world. Nevertheless, researchers have only recently begun to explore its capacity to form biofilms. Strain O55:H7 (DMS9) is a clinical isolate belonging to the atypical EPEC (aEPEC) group, which displays a high degree of genetic relatedness to enterohemorrhagic
E. coli
. Strain DMS9 formed a robust biofilm on an abiotic surface at 26°C, but not at 37°C. It also formed a dense pellicle at the air-liquid interface and developed a red, rough, and dry (RDAR) morphotype on Congo red agar. Unlike a previously described
E. coli
O157:H7 strain, the aEPEC strain seems to express cellulose. Transposon mutagenesis was used to identify biofilm-deficient mutants. One of the mutants was inactivated in the
csgFG
genes, required for assembly and secretion of curli fimbriae, while a second mutant had a mutation in
crl
, a thermosensitive global regulator that modulates σ
S
activity and downstream expression of curli and cellulose. The two mutants were deficient in their biofilm formation capabilities and did not form a pellicle at the air-liquid interface. Unlike in
Salmonella
, the
csgFG
mutant in aEPEC completely lost the RDAR phenotype, while the
crl
mutant displayed a unique RDAR “pizza”-like morphotype. Genetic complementation of the two mutants resulted in restoration of the wild-type phenotype. This report is the first to describe and analyze a multicellular behavior in aEPEC and support a major role for curli and the
crl
regulator in biofilm development at low temperatures corresponding to the nonmammalian host environment.
Detection of Infectious Adenoviruses in Environmental Waters by Fluorescence-Activated Cell Sorting Assay
Authors: Li Dan , He Miao , Jiang Sunny C.
Published: January 2010

Methods for rapid detection and quantification of infectious viruses in the environment are urgently needed for public health protection. A fluorescence-activated cell-sorting (FACS) assay was developed to detect infectious adenoviruses (Ads) based on the expression of viral protein during replication in cells. The assay was first developed using recombinant Ad serotype 5 (rAd5) with the E1A gene replaced by a green fluorescent protein (GFP) gene. Cells infected with rAd5 express GFP, which is captured and quantified by FACS. The results showed that rAd5 can be detected at concentrations of 1 to 10
4
PFU per assay within 3 days, demonstrating a linear correlation between the viral concentration and the number of GFP-positive cells with an
r
2
value of >0.9. Following the same concept, FACS assays using fluorescently labeled antibodies specific to the E1A and hexon proteins, respectively, were developed. Assays targeting hexon showed greater sensitivity than assays targeting E1A. The results demonstrated that as little as 1 PFU Ads was detected by FACS within 3 days based on hexon protein, with an
r
2
value greater than 0.9 over a 4-log concentration range. Application of this method to environmental samples indicated positive detection of infectious Ads in 50% of primary sewage samples and 33% of secondary treated sewage samples, but none were found in 12 seawater samples. The infectious Ads ranged in quantity between 10 and 165 PFU/100 ml of sewage samples. The results indicate that the FACS assay is a rapid quantification tool for detecting infectious Ads in environmental samples and also represents a considerable advancement for rapid environmental monitoring of infectious viruses.
Presence and Characterization of Shiga Toxin-Producing
Escherichia coli
and Other Potentially Diarrheagenic
E. coli
Strains in Retail Meats
Authors: Xia Xiaodong , Meng Jianghong , McDermott Patrick F. , Ayers Sherry , Blickenstaff Karen , Tran Thu-Thuy , Abbott Jason , Zheng Jie , Zhao Shaohua
Published: January 2010

To determine the presence of Shiga toxin-producing
Escherichia coli
(STEC) and other potentially diarrheagenic
E. coli
strains in retail meats, 7,258
E. coli
isolates collected by the U.S. National Antimicrobial Resistance Monitoring System (NARMS) retail meat program from 2002 to 2007 were screened for Shiga toxin genes. In addition, 1,275 of the
E. coli
isolates recovered in 2006 were examined for virulence genes specific for other diarrheagenic
E. coli
strains. Seventeen isolates (16 from ground beef and 1 from a pork chop) were positive for
stx
genes, including 5 positive for both
stx
1
and
stx
2
, 2 positive for
stx
1
, and 10 positive for
stx
2
. The 17 STEC strains belonged to 10 serotypes: O83:H8, O8:H16, O15:H16, O15:H17, O88:H38, ONT:H51, ONT:H2, ONT:H10, ONT:H7, and ONT:H46. None of the STEC isolates contained
eae
, whereas seven carried enterohemorrhagic
E. coli
(EHEC)
hlyA
. All except one STEC isolate exhibited toxic effects on Vero cells. DNA sequence analysis showed that the
stx
2
genes from five STEC isolates encoded mucus-activatable Stx2d. Subtyping of the 17 STEC isolates by pulsed-field gel electrophoresis (PFGE) yielded 14 distinct restriction patterns. Among the 1,275 isolates from 2006, 11 atypical enteropathogenic
E. coli
(EPEC) isolates were identified in addition to 3 STEC isolates. This study demonstrated that retail meats, mainly ground beef, were contaminated with diverse STEC strains. The presence of atypical EPEC strains in retail meat is also of concern due to their potential to cause human infections.
Preparation of Genomic DNA from a Single Species of Uncultured Magnetotactic Bacterium by Multiple-Displacement Amplification
Authors: Arakaki Atsushi , Shibusawa Mie , Hosokawa Masahito , Matsunaga Tadashi
Published: January 2010

Magnetotactic bacteria comprise a phylogenetically diverse group that is capable of synthesizing intracellular magnetic particles. Although various morphotypes of magnetotactic bacteria have been observed in the environment, bacterial strains available in pure culture are currently limited to a few genera due to difficulties in their enrichment and cultivation. In order to obtain genetic information from uncultured magnetotactic bacteria, a genome preparation method that involves magnetic separation of cells, flow cytometry, and multiple displacement amplification (MDA) using φ29 polymerase was used in this study. The conditions for the MDA reaction using samples containing 1 to 100 cells were evaluated using a pure-culture magnetotactic bacterium, “
Magnetospirillum magneticum
AMB-1,” whose complete genome sequence is available. Uniform gene amplification was confirmed by quantitative PCR (Q-PCR) when 100 cells were used as a template. This method was then applied for genome preparation of uncultured magnetotactic bacteria from complex bacterial communities in an aquatic environment. A sample containing 100 cells of the uncultured magnetotactic coccus was prepared by magnetic cell separation and flow cytometry and used as an MDA template. 16S rRNA sequence analysis of the MDA product from these 100 cells revealed that the amplified genomic DNA was from a single species of magnetotactic bacterium that was phylogenetically affiliated with magnetotactic cocci in the
Alphaproteobacteria
. The combined use of magnetic separation, flow cytometry, and MDA provides a new strategy to access individual genetic information from magnetotactic bacteria in environmental samples.
Efficacy of Copper-Silver Ionization in Controlling Biofilm- and Plankton-Associated Waterborne Pathogens
Authors: Shih Hsiu-Yun , Lin Yusen E.
Published: January 2010

The study was to determine the efficacy of copper-silver ionization against the formation of
Pseudomonas aeruginosa
,
Stenotrophomonas maltophilia
, and
Acinetobacter baumannii
in biofilms and planktonic phases. At concentrations below the EPA limits, ionization has potential to control the three waterborne pathogens, in addition to
Legionella
, in hospital water systems for nosocomial infection control.
Detection of 2,4,6-Trinitrotoluene-Utilizing Anaerobic Bacteria by
15
N and
13
C Incorporation
Authors: Gallagher Erin M. , Young Lily Y. , McGuinness Lora M. , Kerkhof Lee J.
Published: January 2010

2,4,6-Trinitrotoluene (
15
N or
13
C labeled) was added to Norfolk Harbor sediments to test whether anaerobic bacteria use TNT for growth. Stable-isotope probing (SIP)-terminal restriction fragment length polymorphism (TRFLP) detected peaks in the [
15
N]TNT cultures (60, 163, and 168 bp). The 60-bp peak was also present in the [
13
C]TNT cultures and was related to
Lysobacter taiwanensis
.
Rapid and Specific Method for Evaluating
Streptomyces
Competitive Dynamics in Complex Soil Communities
Authors: Schlatter Daniel C. , Samac Deborah A. , Tesfaye Mesfin , Kinkel Linda L.
Published: January 2010

Quantifying target microbial populations in complex communities remains a barrier to studying species interactions in soil environments. Quantitative PCR (qPCR) assays were developed for quantifying pathogenic
Streptomyces scabiei
and antibiotic-producing
Streptomyces lavendulae
strains in complex soil communities. This assay will be useful for evaluating the competitive dynamics of streptomycetes in soil.
Mannheimia succiniciproducens
Phosphotransferase System for Sucrose Utilization
Authors: Lee Jeong Wook , Choi Sol , Kim Ji Mahn , Lee Sang Yup
Published: January 2010

The succinic acid producer
Mannheimia succiniciproducens
can efficiently utilize sucrose as a carbon source, but its metabolism has not been understood. This study revealed that
M. succiniciproducens
uses a sucrose phosphotransferase system (PTS), sucrose 6-phosphate hydrolase, and a fructose PTS for the transport and utilization of sucrose.
Efficient Production of 2-Oxobutyrate from 2-Hydroxybutyrate by Using Whole Cells of
Pseudomonas stutzeri
Strain SDM
Authors: Gao Chao , Zhang Wen , Lv Chuanjuan , Li Lixiang , Ma Cuiqing , Hu Chunhui , Xu Ping
Published: January 2010

2-Oxobutyrate is an important intermediate in the chemical, drug, and food industries. Whole cells of
Pseudomonas stutzeri
SDM, containing NAD-independent lactate dehydrogenases, effectively converted 2-hydroxybutyrate into 2-oxobutyrate. Under optimal conditions, the biocatalytic process produced 2-oxobutyrate at a high concentration (44.4 g liter
−1
) and a high yield (91.5%).
Exploiting the Role of TolC in Pathogenicity: Identification of a Bacteriophage for Eradication of
Salmonella
Serovars from Poultry
Authors: Ricci Vito , Piddock Laura J. V.
Published: January 2010

Using a screening procedure, three bacteriophages, ST27, ST29, and ST35, were identified with selective activity for
Salmonella enterica
serovar Typhimurium (SL1344) but not SL1344
tolC
::
aph
. Overproduction of TolC led to a lower efficiency of plating (EOP), further suggesting that TolC was the target receptor. Activity against other serovars of
Salmonella
was observed but not against other species of
Enterobacteriaceae
. This study provides proof of principle that bacteriophages can be active against the outer membrane protein of tripartite resistance-nodulation-division (RND) efflux pumps and so could be used to reduce the numbers of
Salmonella
cells in animals reared for food production.
Effects of Aeration on the Synthesis of Poly(3-Hydroxybutyrate) from Glycerol and Glucose in Recombinant
Escherichia coli
Authors: de Almeida Alejandra , Giordano Andrea M. , Nikel Pablo I. , Pettinari M. Julia
Published: January 2010

Bioreactor cultures of
Escherichia coli
recombinants carrying
phaBAC
and
phaP
of
Azotobacter
sp. FA8 grown on glycerol under low-agitation conditions accumulated more poly(3-hydroxybutyrate) (PHB) and ethanol than at high agitation, while in glucose cultures, low agitation led to a decrease in PHB formation. Cells produced smaller amounts of acids from glycerol than from glucose. Glycerol batch cultures stirred at 125 rpm accumulated, in 24 h, 30.1% (wt/wt) PHB with a relative molecular mass of 1.9 MDa, close to that of PHB obtained using glucose.