bluuebunny/crossref_metadata_2025 huggingface dataset:
Association between childhood atopic dermatitis, malnutrition, and low bone mineral density: A US population‐based study
Authors: Silverberg Jonathan I.
Published: December 2014

Background

Children with atopic dermatitis (AD) have multiple risk factors for low bone mineral density (BMD).

Methods

We analyzed data from 3049 children and adolescents aged 8–19 yrs from the 2005–2006 National Health and Nutrition Examination Survey, including a cross‐sectional questionnaire, dual energy X‐ray absorptiometry, and blood samples.

Results

In multivariate models that controlled for age, sex, race/ethnicity, level of education and household income, body mass index (BMI), and smoking in the household, AD was associated with lower BMD z‐score for the total femur (survey linear regression; adjusted β [95% CI]: −0.42 [0.68, −0.16]), including trochanter (−0.29 [−0.54, −0.05]) and femoral neck (−0.29 [−0.53, −0.05]) and total lumbar spine (−0.31 [−0.52, −0.11]). Children with AD had higher median levels of serum IgE (110.0 vs. 53.0 kU/l), peripheral lymphocyte (2.9 vs. 2.5 × 103 cells/μl), and eosinophil counts (0.3 vs. 0.2 × 103 cells/μl) (Mann–Whitney U‐test, p ≤ 0.003 for all), but not CRP levels (0.03 vs. 0.04 mg/dl) and higher odds of 25‐OH vitamin D deficiency (survey logistic regression; odds ratio [OR] [95% CI]: 4.81 [1.21, 20.81]), low calcium (2.56 [1.24, 5.28]), low alkaline phosphatase (2.56 [1.20, 5.44]), and higher tertiles of LDH (tertile 2: 6.36 [1.75, 23.18]; tertile‐3: 4.57 [1.32, 15.85]), but not parathyroid hormone (PTH) or albumin. Finally, children with AD had higher rates of low BMD, that is, BMD z‐score <−2, of the femur (23.4% vs. 18.4%) and spine (35.3% vs. 24.5%). In multivariate logistic regression models of low BMD of femur and/or spine using stepwise selection of the 30 sociodemographic and clinical factors, laboratory values, and medications used, AD remained a significant covariate (1.33 [1.32–1.34]). The covariates with the largest effects on low BMD were low PTH and albumin, higher basophil count, Hispanic ethnicity, and BMI <5th percentile. Among children with AD, 56.2% of those with Hispanic origin, 52.8% with BMI <5th percentile, 75.0% with low albumin, and 54.0% with low PTH had low BMD.

Conclusions

Children with AD have lower BMD, particularly those with malnutrition and Hispanic ethnicity.
Factors associated with asthma control in children: findings from a national Web‐based survey
Authors: Sasaki Mari , Yoshida Koichi , Adachi Yuichi , Furukawa Mayumi , Itazawa Toshiko , Odajima Hiroshi , Saito Hirohisa , Akasawa Akira
Published: December 2014

Background

Although achieving and maintaining control of asthma is considered to be the goal of asthma treatment, determinants of asthma control are not fully understood. Our aim was to assess factors associated with asthma control among paediatric patients in the general population.

Methods

In June 2012, a Web‐based survey was conducted to identify Japanese children aged 6 to 11 yr who currently have asthma and evaluate control of their disease using the Childhood Asthma Control Test (C‐ACT). Associations were evaluated among uncontrolled asthma (C‐ACT score <20) between environmental factors, demographics and comorbid allergic diseases.

Results

Among the 3066 children with current asthma, 447 (14.6%) had uncontrolled asthma. Multivariable analysis identified factors such as low birthweight (adjusted OR 1.65, 95% CI 1.25–2.18), obesity (adjusted OR 1.44, 95% CI 1.05–1.99) and pet ownership before birth (adjusted OR 1.68, 95% CI 1.24–2.29) to be associated with uncontrolled disease. Comorbid allergic diseases, especially rhinitis were a significant risk of uncontrolled asthma (adjusted OR for severe rhinitis: 3.88, 95% CI 2.50–6.00). The severity of rhinitis symptoms was inversely correlated with the C‐ACT score (p < 0.001).

Conclusions

A population‐based Web survey showed an association between several factors and the control of paediatric asthma. The assessment of these factors may help identify the children at risk with uncontrolled asthma.
Exercise‐induced bronchospasm diagnosis in children. Utility of combined lung function tests
Authors: Sánchez‐García Silvia , Rodríguez del Río Pablo , Escudero Carmelo , García‐Fernández Cristina , Ibáñez Maria Dolores
Published: December 2014

Background

The diagnosis of exercise‐induced asthma or bronchospasm (EIB) is a complex dare in daily clinical practice. The consensus is that if bronchial hyper‐responsiveness (BHR) is demonstrated in a patient with symptoms consistent with EIB, then that patient can be diagnosed with exercise‐induced bronchospasm. The aim of this study was to determine which BHR test is the most efficient to diagnose EIB.

Methods

Children under 16, without previous asthma diagnosis, or with stable asthma, complaining of asthma‐like symptoms triggered by exercise were included. Bronchodilator, methacholine, mannitol, and exercise tests were performed on all patients, following established protocols. The performance of single and combined tests was determined.

Results

Of 46 patients (median age: 12 yr, ranged 8–16 y.o.) were recruited, 30 (70%) previously diagnosed of asthma. BHR was detected in 93.47% of the children. The exercise challenge test detected BHR in 11 of 46 (23.90%) patients, bronchodilator test in 10 of 46 (21.70%), mannitol in 36 of 45 (80%) and methacholine in 41 of 45 (91.11%). The total number of patients with BHR was detected using a combination of the methacholine and mannitol tests. A combination of the methacholine test performed first, followed by the mannitol test, was able to diagnose BHR in 100% of children with lower number of tests (n = 45) than if the order was reversed (n = 50).

Conclusions

Methacholine and mannitol tests detect BHR in most children with suspected EIB. Bronchodilator and exercise tests show a low positivity rate. A combination of the methacholine test, followed by the mannitol test, gives the highest return to identify BHR in children for the diagnosis of EIB.
Recurrent Pustular Eruption Masquerading as Pustular Psoriasis in Netherton Syndrome
Authors: Mendiratta Vibhu , Yadav Pravesh , Chander Ram , Aggarwal Shilpi
Published: December 2014

We report a unique presentation of Netherton syndrome with recurrent pustular eruptions leading to an erroneous diagnosis of infantile pustular psoriasis. Light microscopy of eyebrow hair showed trichorrhexis invaginata, consistent with Netherton syndrome.
Risk of respiratory syncytial virus infection in infants with congenital cystic lung disease
Authors: Hama Ikuko , Takahashi Shigehiro , Nakamura Tomoo , Ito Yushi , Kawasaki Kazuteru , Sago Haruhiko
Published: December 2014

Background

Congenital cystic lung disease (CCLD), which includes congenital cystic adenomatoid malformation, bronchopulmonary sequestration, and congenital lobar emphysema, has been reported to increase the risk of recurrent respiratory infection. In particular, respiratory syncytial virus (RSV) causes severe lower respiratory tract disease in high‐risk infants. The objective of this study was to investigate the risk of severe RSV infection in infants with CCLD.

Methods

Infants antenatally diagnosed as having CCLD and admitted to a neonatal intensive care unit at the National Center for Child Health and Development in Tokyo between September 2002 and October 2011 were included in this study. We investigated retrospectively whether the infants were hospitalized with RSV infection by 24 months of age using their medical records.

Results

Forty‐eight infants were antenatally diagnosed as having CCLD. Of the 48 infants, four (8.3%) were hospitalized with RSV infection by 24 months of age.

Conclusions

Infants with CCLD have increased risk of severe RSV infection.
Acoustic improvements after surgical correction in congenital heart disease
Authors: Joo Chan Uhng , Choi Yoon Mi , Kim Sun Jun
Published: December 2014

Background

Hoarse or asthenic voice is frequently associated with various pediatric cardiac disorders. The aim of this study was to investigate the changes in voice physiology after surgical correction in patients with congenital heart diseases.

Methods

We performed voice analysis using induced crying of 40 infants with congenital heart disease (CHD) such as ventricular septal defect (VSD), patent ductus arteriosus (PDA), and atrial septal defect (ASD; 31 girls, 24 boys; mean age, 11 ± 8.9 months). Cries were serially recorded immediately prior to operation, then 1 week, and 1 month after surgical correction, respectively. Acoustic parameters, fundamental frequency (F0), duration of cry, noise to harmonic ratio (NHR), jitter, and shimmer, were extracted using Multi‐Dimensional Voice Program™ (MDVP) a computerized speech analysis system. Cries were compared with 30 normal healthy infants of corresponding age.

Results

Among the 25 infants with VSD, cry duration, jitter, and shimmer improved after the operation (P < 0.05). F0 and NHR, however, were not significantly different. F0 in patients with PDA improved, but was not statistically significant. The duration of cry, jitter, shimmer, and NHR improved in the PDA group (P < 0.05). The jitter and shimmer parameters improved significantly (P < 0.05), but F0, cry duration, and NHR in patients with ASD did not show any significant changes.

Conclusions

Deviated voice patterns in pediatric patients with CHD can normalize after surgical correction. In addition, non‐invasive analysis such as MDVP can be used to identify vocal paralysis, even in the early postoperative period.
Serum ischemia‐modified albumin and oxidized LDL in cord blood and serum of neonates born to pre‐eclamptic mothers
Authors: Mehmetoglu Idris , Kurban Sevil , Toker Aysun , Annagür Ali , Altunhan Hüseyin , Erbay Ekrem , Örs Rahmi
Published: December 2014

Background

We investigated oxidized low‐density lipoprotein (OxLDL) and ischemia‐modified albumin (IMA) in cord blood and neonatal blood of 7‐day‐old neonates born to pre‐eclamptic and normotensive healthy mothers.

Methods

The study was performed on 30 neonates born to pre‐eclamptic and 20 neonates born to normotensive mothers. IMA and OxLDL were determined on spectrophotometry and ELISA, respectively.

Results

IMA in cord blood was higher in the pre‐eclamptic group as compared with the normotensive group, but the difference between the groups was not significant. IMA in neonate venous blood was significantly higher in the pre‐eclamptic group than in the normotensive group (P < 0.001). OxLDL in both cord blood and in neonate venous blood was significantly higher in the pre‐eclamptic group compared with the normotensive group (P < 0.001). IMA and OxLDL were significantly decreased after delivery in both groups.

Conclusions

Significantly increased cord blood OxLDL and significantly increased OxLDL and IMA 7 days after birth in neonates born to pre‐eclamptic mothers might be an indicator of increased oxidative stress in pre‐eclampsia.
Expression of Matrix Metalloproteinases (MMP‐2, MMP‐9) and their Inhibitors (TIMP‐1, TIMP‐2) in Canine Testis, Epididymis and Semen
Authors: Warinrak C , Wu J‐T , Hsu W‐L , Liao J‐W , Chang S‐C , Cheng F‐P
Published: December 2014

Contents

This study aims to investigate the role of matrix metalloproteinases (MMPs) in determining semen quality and to evaluate the expression and cellular localization of MMP‐2, MMP‐9, tissue inhibitor of metalloproteinase‐1 (TIMP‐1) and TIMP‐2 in the testes, epididymis and ejaculated spermatozoa. Gelatinase activities between normal (n = 21) and abnormal (n = 25) semen samples showed a significant, sixfold increase in proMMP‐2 and MMP‐2 activity in high than low sperm concentration samples (p < 0.001). ProMMP‐9 and MMP‐9 levels were significantly elevated in samples with low sperm counts compared to those with high sperm density (p < 0.001). High levels of proMMP‐2 and MMP‐2 were associated with high sperm motility (≥70%, p < 0.001). Sperm‐rich fraction showed significantly (eight‐fold) higher proMMP‐9 enzymatic activity compared with prostatic fraction. The mRNA expressions of MMP‐2, MMP‐9, TIMP‐1 and TIMP‐2 were confirmed in testicular and epididymal tissues. Immunohistochemical staining illustrated the MMP‐2‐specific strong immunoreactivity in the head of mature spermatids during spermatogenesis, whereas MMP‐9, TIMP‐1 and TIMP‐2 were absent in these cells. Matrix metalloproteinase‐9 immunoreactivity was observed in the spermatocyte and round spermatid, whereas TIMP‐1 was only exhibited in the residual bodies. Immunolabeling of epididymal and ejaculated sperm demonstrated MMP‐2 localization along acrosomal region of sperm, while MMP‐9, TIMP‐1 and TIMP‐2 localization was merely limited to the flagella. In conclusion, spermatozoa initially acquire MMP‐2 during their formation at testicular level, and the presence of this protein persists through the epididymal transit and up to ejaculate. The enzymatic activity of MMP‐2 and MMP‐9 may serve as an alternative biomarker in determining semen quality.
Identifying and Referring Youths at Risk for Suicide Following Participation in School‐Based Gatekeeper Training
Authors: Susanne Condron Donna , Garraza Lucas Godoy , Walrath Christine M. , McKeon Richard , Goldston David B. , Heilbron Nicole S.
Published: December 2014

Gatekeeper training is a core strategy of the Garrett Lee Smith Memorial Suicide Prevention Act of 2004. Using data gathered from school‐based gatekeeper trainings implemented by GLS grantees, this analysis examines training and gatekeeper factors associated with (1) identification and referral patterns and (2) services at‐risk youths receive. Time spent interacting with youths was positively correlated with the number of gatekeeper identifications and knowledge about service receipt. Gatekeepers who participated in longer trainings identified proportionately more at‐risk youths than participants in shorter trainings. Most gatekeeper trainees referred the identified youths to services regardless of training type.
Psychosocial–Environmental Risk Factors for Suicide Attempts in Adolescents with Suicidal Ideation: Findings from a Sample of 73,238 Adolescents
Authors: Kim Sun Mi , Baek Ji Hyun , Han Doug Hyun , Lee Young Sik , Yurgelun‐Todd Deborah A.
Published: December 2014

We determined risk factors that discriminate between suicide attempt (SA) adolescents and suicidal ideation only (SI only) adolescents using data from the 2010 Korea Youth Risk Behavior Web‐based Survey (12–19 years; N = 73,238). In males, heavy alcohol use, drug use, and high perceived sadness/hopelessness showed significant effects on the presence of SA versus the presence of SI only. In females, along with these variables, low academic achievement, poor perceived health status, high perceived stress, and unhealthy coping strategy were also significantly related to the presence of SA versus SI only. Therefore, clinical interventions targeting adolescents' psychological distress are warranted to prevent suicide.
Suicidal Behavior in Relatives or Associates Moderates the Strength of Common Risk Factors for Suicide
Authors: Tong Yongsheng , Phillips Michael R. , Duberstein Paul , Zhan Weihai
Published: December 2014

The prevalence and odds ratios of different suicide risk factors were compared in three pairs of decedents: 80 suicides and 25 injury decedents with blood relatives with suicidal behavior history (biologically exposed); 259 suicides and 126 injury decedents with unrelated acquaintances with suicidal behavior history (socially exposed); and 471 suicides and 523 injury decedents with neither relatives nor acquaintances with suicidal behavior history (unexposed). Negative life events and high psychological stress were more common in socially exposed suicides than in other suicides. The adjusted odds ratios of most established suicide risk factors were higher in unexposed decedents than in biologically or socially exposed decedents, suggesting that the predictive value of established risk factors wanes in individuals who have been exposed to suicidal behavior in family or friends.
A steep ramp test is valid for estimating maximal power and oxygen uptake during a standard ramp test in type 2 diabetes
Authors: Rozenberg R. , Bussmann J. B. J. , Lesaffre E. , Stam H. J. , Praet S. F. E.
Published: December 2014

A short maximal steep ramp test (SRT, 25 W/10 s) has been proposed to guide exercise interventions in type 2 diabetes, but requires validation. This study aims to (a) determine the relationship between Wmax and reached during SRT and the standard ramp test (RT); (b) obtain test‐retest reliability; and (c) document electrocardiogram (ECG) abnormalities during SRT. Type 2 diabetes patients (35 men, 26 women) performed a cycle ergometer‐based RT (women 1.2; men 1.8 W/6 s) and SRT on separate days. A random subgroup (n = 42) repeated the SRT. ECG, heart rate, and were monitored. Wmax during RT: 193 ± 63 (men) and 106 ± 33 W (women). Wmax during SRT: 193 ± 63 (men) and 188 ± 55 W (women). The relationship between RT and SRT was described by men RT (mL/min) = 152 + 7.67 × Wmax SRT1 (r: 0.859); women RT (mL/min) = 603 + 4.75 × Wmax SRT1 (r: 0.771); intraclass correlation coefficients between first (SRT1) and second SRT Wmax (SRT2) were men 0.951 [95% confidence interval (CI) 0.899–0.977] and women 0.908 (95% CI 0.727–0.971). No adverse events were noted during any of the exercise tests. This validation study indicates that the SRT is a low‐risk, accurate, and reliable test to estimate maximal aerobic capacity during the RT to design exercise interventions in type 2 diabetes patients.
The determinants of thermal comfort in cool water
Authors: Guéritée J. , House J. R. , Redortier B. , Tipton M. J.
Published: December 2014

Water‐based activities may result in the loss of thermal comfort (TC). We hypothesized that in cooling water, the hands and feet would be responsible. Supine immersions were conducted in up to five clothing conditions (exposing various regions), as well as investigations to determine if a “reference” skin temperature (Tsk) distribution in thermoneutral air would help interpret our findings. After 10 min in 34.5 °C water, the temperature was decreased to 19.5 °C over 20 min; eight resting or exercising volunteers reported when they no longer felt comfortable and which region was responsible. TC, rectal temperature, and Tsk were measured. Rather than the extremities, the lower back and chest caused the loss of overall TC. At this point, mean (SD) chest Tsk was 3.3 (1.7) °C lower than the reference temperature (P = 0.005), and 3.8 (1.5) °C lower for the back (P = 0.002). Finger Tsk was 3.1 (2.7) °C higher than the reference temperature (P = 0.037). In cool and cooling water, hands and feet, already adapted to colder air temperatures, will not cause discomfort. Contrarily, more discomfort may arise from the chest and lower back, as these regions cool by more than normal. Thus, Tsk distribution in thermoneutral air may help understand variations in TC responses across the body.
Muscle enzyme and fiber type‐specific sarcomere protein increases in serum after inertial concentric‐eccentric exercise
Authors: Carmona G. , Guerrero M. , Cussó R. , Padullés J.M. , Moras G. , Lloret M. , Bedini J.L. , Cadefau J.A.
Published: December 2014

Muscle damage induced by inertial exercise performed on a flywheel device was assessed through the serum evolution of muscle enzymes, interleukin 6, and fiber type‐specific sarcomere proteins such as fast myosin (FM) and slow myosin (SM). We hypothesized that a model of muscle damage could be constructed by measuring the evolution of serum concentration of muscle proteins following inertial exercise, according to their molecular weight and the fiber compartment in which they are located. Moreover, by measuring FM and SM, the type of fibers that are affected could be assessed. Serum profiles were registered before and 24, 48, and 144 h after exercise in 10 healthy and recreationally active young men. Creatine kinase (CK) and CK‐myocardial band isoenzyme increased in serum early (24 h) and returned to baseline values after 48 h. FM increased in serum late (48 h) and remained elevated 144 h post‐exercise. The increase in serum muscle enzymes suggests increased membrane permeability of both fast and slow fibers, and the increase in FM reveals sarcomere disruption as well as increased membrane permeability of fast fibers. Consequently, FM could be adopted as a fiber type‐specific biomarker of muscle damage.
The Effects of Integrated Science, Technology, and Engineering Education on Elementary Students' Knowledge and Identity Development
Authors: Yoon So Yoon , Dyehouse Melissa , Lucietto Anne M. , Diefes‐Dux Heidi A. , Capobianco Brenda M.
Published: December 2014

This study examines the effects of integrated science, technology, and engineering (STE) education on second‐, third‐, and fourth‐grade students' STE content knowledge and aspirations concerning engineering after validation of the measures. During the 2009–2010 school year, 59 elementary school teachers, who attended a week‐long engineering teacher professional development (TPD) program, implemented STE integrated lessons in schools in a large, south‐central U.S. school district. At the beginning and end of the school year, the Student Knowledge Tests (SKTs) and the Engineering Identity Development Scale (EIDS) were administered to 831 students either in classrooms with the STE integrated lessons (treatment) or without (control). Item and confirmatory factor analyses provided sufficient reliability and validity evidence of the SKTs. Significant differences between treatment and control groups for all three grades on the post‐SKTs indicate the impact of STE integration on students' content knowledge. The EIDS showed no significant group differences on the academic subscale, while the engineering career subscale showed that treatment group students scored significantly higher than control group students in all three grades. Those significant changes in the treatment group in knowledge and aspirations are strong evidence for the potential impact of STE integration.
Applying NAEP to Improve Mathematics Content and Methods Courses for Preservice Elementary and Middle School Teachers
Authors: Goodson‐Espy Tracy , Cifarelli Victor V. , Pugalee David , Lynch‐Davis Kathleen , Morge Shelby , Salinas Tracie
Published: December 2014

This study explored how mathematics content and methods courses for preservice elementary and middle school teachers could be improved through the integration of a set of instructional materials based on the National Assessment of Educational Progress (NAEP). A set of eight instructional modules was developed and tested. The study involved 7 university instructors and 542 preservice teachers (PSTs) from three different universities. A quasi‐experimental nonequivalent groups design was used for this study in which the following data sources were collected and analyzed. Three versions of a Learning Mathematics for Teaching test were given to assess PSTs‘ mathematical content knowledge for teaching: (a) Elementary Number Concepts and Operations—Content Knowledge; (b) Elementary Geometry—Content Knowledge; and (c) Middle School Number Concepts and Operations—Content Knowledge. In addition, the Mathematics Teacher Efficacy Beliefs Instrument was given to assess PSTs’ teacher efficacy beliefs. Test results were analyzed using paired samples t‐tests. Findings suggest that use of instructional materials, based on NAEP, with PSTs results in increases in their mathematical content knowledge for teaching and in their teaching efficacy beliefs.
Vibration Suppression of Subharmonic Resonance Response Using a Nonlinear Vibration Absorber
Authors: EL-Sayed A. T. , Bauomy H. S.
Published: December 2014

This paper is concerned with the vibration of a two degree-of-freedom (2DOF) nonlinear system subjected to multiparametric excitation forces. The vibrating motion of the system is described by the coupled differential equations having both quadratic and cubic terms. The aim of this work is to use a nonlinear absorber to control the vibration of the nonlinear system near the simultaneous subharmonic and internal resonances, where the vibrations are severe. Multiple scale perturbation technique (MSPT) is applied to obtain the averaged equations up to the second-order approximation. The steady-state response and their stability are studied numerically for the nonlinear system at the simultaneous subharmonic and internal resonances. Some recommendations regarding to the different system parameters are given following studying the effects of various parameters. Comparison with the available published work is made.
Thermosolutocapillary Convection in an Open Rectangular Cavity With Dynamic Free Surface
Authors: Zhou Xiaoming , Huai Xiulan
Published: December 2014

Thermosolutocapillary convection within a rectangular cavity with dynamic free surface is numerically investigated in the absence of gravitational effects. Both the temperature and solute concentration gradients are applied horizontally. The free surface deformation is captured by the level set method. Two cases of the ratio of thermal to solutal Marangoni number Rσ < −1 and Rσ = −1 are considered. For Rσ < −1, the free surface bulges out near the left wall and bulges in near the right wall; with the increase of Marangoni number, the free surface deformation decreases and with the increase of capillary number and aspect ratio, it increases. For Rσ = −1, the free surface bulges out near the left and right walls and bulges in at the central zone; with the increase of Marangoni number, the free surface deformation mode is changed and with the increase of capillary number and aspect ratio, the free surface deformation increases.
Older Adult Hill Transition Strategies are Determined by Task Demands and Cautious Gait Patterns
Authors: Sheehan Riley C. , Gottschall Jinger S.
Published: December 2014

Falls are the leading cause of injury for all age groups. However, adults over 65 are at a higher risk, with one-third falling each year. Transitioning between level and hill surfaces poses a greater fall risk than walking on either surface alone. Previous studies found that young adults adopted a cautious gait pattern to mitigate this risk. As older adults typically employ a cautious pattern during level walking, we investigated how they modify their gait pattern to safely transition between surfaces. Twenty adults over the age of 65 transitioned onto and off of a 15° ramp while we recorded kinematics and muscle activity. During the level-to-downhill and uphill-to-level transitions, participants took slower, shorter steps indicative of an exaggerated cautious gait pattern. The older adults also exhibited greater muscle activity during the transitions, which may be due to muscle weakness requiring compensatory strategies to meet the greater demands of the task. However, the slower, shorter steps when transitioning from uphill to level suggest that these compensations may not always be adequate. Thus, it is important to consider the relationship between physical abilities and task demands in evaluating walking terrains that may be excessively difficult or dangerous for older adults.
Deciphering Information Flow in T Cells
Authors: Ray L. Bryan
Published: December 2014

A computational method quantifies information flow in T cells.
In Vitro
Resistance Studies with Bacteria That Exhibit Low Mutation Frequencies: Prediction of “Antimutant” Linezolid Concentrations Using a Mixed Inoculum Containing both Susceptible and Resistant Staphylococcus aureus
Authors: Firsov Alexander A. , Golikova Maria V. , Strukova Elena N. , Portnoy Yury A. , Romanov Andrey V. , Edelstein Mikhail V. , Zinner Stephen H.
Published: December 2014

Bacterial resistance studies using
in vitro
dynamic models are highly dependent on the starting inoculum that might or might not contain spontaneously resistant mutants (RMs). To delineate concentration-resistance relationships with linezolid-exposed
Staphylococcus aureus
, a mixed inoculum containing both susceptible cells and RMs was used. An RM selected after the 9th passage of the parent strain (MIC, 2 μg/ml) on antibiotic-containing media (RM9; MIC, 8 μg/ml) was chosen for the pharmacodynamic studies, because the mutant prevention concentration (MPC) of linezolid against the parent strain in the presence of RM9 at 10
2
(but not at 10
4
) CFU/ml did not differ from the MPC value determined in the absence of the RMs. Five-day treatments with twice-daily linezolid doses were simulated at concentrations either between the MIC and MPC or above the MPC.
S. aureus
RMs (resistant to 2× and 4× MIC but not 8× and 16× MIC) were enriched at ratios of the 24-h area under the concentration-time curve (AUC
24
) to the MIC that provide linezolid concentrations between the MIC and MPC for 100% (AUC
24
/MIC, 60 h) and 86% (AUC
24
/MIC, 120 h) of the dosing interval. No such enrichment occurred when linezolid concentrations were above the MIC and below the MPC for a shorter time (37% of the dosing interval; AUC
24
/MIC, 240 h) or when concentrations were consistently above the MPC (AUC
24
/MIC, 480 h). These findings obtained using linezolid-susceptible staphylococci supplemented with RMs support the mutant selection window hypothesis. This method provides an option to delineate antibiotic concentration-resistance relationships with bacteria that exhibit low mutation frequencies.
Evolution of Staphylococcus aureus under Vancomycin Selective Pressure: the Role of the Small-Colony Variant Phenotype
Authors: Lenhard Justin R. , von Eiff Christof , Hong Irene S. , Holden Patricia N. , Bear Michael D. , Suen Amy , Bulman Zackery P. , Tsuji Brian T.
Published: December 2014

Staphylococcus aureus
small-colony variants (SCVs) often persist despite antibiotic therapy. Against a 10
8
-CFU/ml methicillin-resistant
S. aureus
(MRSA) (strain COL) population of which 0%, 1%, 10%, 50%, or 100% was an isogenic
hemB
knockout (Ia48) subpopulation displaying the SCV phenotype, vancomycin achieved maximal reductions of 4.99, 5.39, 4.50, 3.28, and 1.66 log
10
CFU/ml over 48 h. Vancomycin at ≥16 mg/liter shifted a population from 50% SCV cells at 0 h to 100% SCV cells at 48 h, which was well characterized by a Hill-type model (
R
2
> 0.90).
Discovery of Two Novel Viruses Expands the Diversity of Single-Stranded DNA and Single-Stranded RNA Viruses Infecting a Cosmopolitan Marine Diatom
Authors: Kimura Kei , Tomaru Yuji
Published: December 2014

Recent studies have suggested that diatom viruses are an important factor affecting diatom population dynamics, which in turn are important in considering marine primary productivity. The marine planktonic diatom
Chaetoceros tenuissimus
Meunier is a cosmopolitan species and often causes blooms off the western coast of Japan. To date, two viruses,
C. tenuissimus
DNA virus (CtenDNAV) type I and CtenRNAV type I, have been identified that potentially affect
C. tenuissimus
population dynamics in the natural environment. In this study, we successfully isolated and characterized two additional novel viruses (CtenDNAV type II and CtenRNAV type II). This paper reports the basic characteristics of these new viruses isolated from surface water or sediment from the Hiroshima Bay, Japan. The physiological and morphological characteristics of the two new viruses were similar to those of the previously isolated viruses. However, the amino acid sequences of the structural proteins of CtenDNAV type II and CtenRNAV type II were clearly distinct from those of both type I viruses, with identity scores of 38.3% and 27.6%, respectively. Our results suggest that at least four genetically distinct viruses sharing the same diatom host are present in western Japan and affect the population dynamics of
C. tenuissimus
. Moreover, the result that CtenRNAV type II lysed multiple diatom species indicates that RNA viruses may affect various diatom populations in the natural environment.
The Zeamine Antibiotics Affect the Integrity of Bacterial Membranes
Authors: Masschelein Joleen , Clauwers Charlien , Stalmans Karen , Nuyts Koen , De Borggraeve Wim , Briers Yves , Aertsen Abram , Michiels Chris W. , Lavigne Rob
Published: December 2014

The zeamines (zeamine, zeamine I, and zeamine II) constitute an unusual class of cationic polyamine-polyketide-nonribosomal peptide antibiotics produced by
Serratia plymuthica
RVH1. They exhibit potent bactericidal activity, killing a broad range of Gram-negative and Gram-positive bacteria, including multidrug-resistant pathogens. Examination of their specific mode of action and molecular target revealed that the zeamines affect the integrity of cell membranes. The zeamines provoke rapid release of carboxyfluorescein from unilamellar vesicles with different phospholipid compositions, demonstrating that they can interact directly with the lipid bilayer in the absence of a specific target. DNA, RNA, fatty acid, and protein biosynthetic processes ceased simultaneously at subinhibitory levels of the antibiotics, presumably as a direct consequence of membrane disruption. The zeamine antibiotics also facilitated the uptake of small molecules, such as 1-N-phenylnaphtylamine, indicating their ability to permeabilize the Gram-negative outer membrane (OM). The valine-linked polyketide moiety present in zeamine and zeamine I was found to increase the efficiency of this process. In contrast, translocation of the large hydrophilic fluorescent peptidoglycan binding protein PBD
KZ
-GFP was not facilitated, suggesting that the zeamines cause subtle perturbation of the OM rather than drastic alterations or defined pore formation. At zeamine concentrations above those required for growth inhibition, membrane lysis occurred as indicated by time-lapse microscopy. Together, these findings show that the bactericidal activity of the zeamines derives from generalized membrane permeabilization, which likely is initiated by electrostatic interactions with negatively charged membrane components.
Identification of a Wide Range of Motifs Inhibitory to Shiga Toxin by Affinity-Driven Screening of Customized Divalent Peptides Synthesized on a Membrane
Authors: Kato Mihoko , Watanabe-Takahashi Miho , Shimizu Eiko , Nishikawa Kiyotaka
Published: December 2014

Shiga toxin (Stx), a major virulence factor of enterohemorrhagic
Escherichia coli
, binds to target cells through a multivalent interaction between its B-subunit pentamer and the cell surface receptor globotriaosylceramide, resulting in a remarkable increase in its binding affinity. This phenomenon is referred to as the “clustering effect.” Previously, we developed a multivalent peptide library that can exert the clustering effect and identified Stx neutralizers with tetravalent peptides by screening this library for high-affinity binding to the specific receptor-binding site of the B subunit. However, this technique yielded only a limited number of binding motifs, with some redundancy in amino acid selectivity. In this study, we established a novel technique to synthesize up to 384 divalent peptides whose structures were customized to exert the clustering effect on the B subunit on a single cellulose membrane. By targeting Stx1a, a major Stx subtype, the customized divalent peptides were screened to identify high-affinity binding motifs. The sequences of the peptides were designed based on information obtained from the multivalent peptide library technique. A total of 64 candidate motifs were successfully identified, and 11 of these were selected to synthesize tetravalent forms of the peptides. All of the synthesized tetravalent peptides bound to the B subunit with high affinities and effectively inhibited the cytotoxicity of Stx1a in Vero cells. Thus, the combination of the two techniques results in greatly improved efficiency in identifying biologically active neutralizers of Stx.
High-Resolution Taxonomic Profiling of the Subgingival Microbiome for Biomarker Discovery and Periodontitis Diagnosis
Authors: Szafranski Szymon P. , Wos-Oxley Melissa L. , Vilchez-Vargas Ramiro , Jáuregui Ruy , Plumeier Iris , Klawonn Frank , Tomasch Jürgen , Meisinger Christa , Kühnisch Jan , Sztajer Helena , Pieper Dietmar H. , Wagner-Döbler Irene
Published: December 2014

The oral microbiome plays a key role for caries, periodontitis, and systemic diseases. A method for rapid, high-resolution, robust taxonomic profiling of subgingival bacterial communities for early detection of periodontitis biomarkers would therefore be a useful tool for individualized medicine. Here, we used Illumina sequencing of the V1-V2 and V5-V6 hypervariable regions of the 16S rRNA gene. A sample stratification pipeline was developed in a pilot study of 19 individuals, 9 of whom had been diagnosed with chronic periodontitis. Five hundred twenty-three operational taxonomic units (OTUs) were obtained from the V1-V2 region and 432 from the V5-V6 region. Key periodontal pathogens like
Porphyromonas gingivalis
,
Treponema denticola
, and
Tannerella forsythia
could be identified at the species level with both primer sets. Principal coordinate analysis identified two outliers that were consistently independent of the hypervariable region and method of DNA extraction used. The linear discriminant analysis (LDA) effect size algorithm (LEfSe) identified 80 OTU-level biomarkers of periodontitis and 17 of health. Health- and periodontitis-related clusters of OTUs were identified using a connectivity analysis, and the results confirmed previous studies with several thousands of samples. A machine learning algorithm was developed which was trained on all but one sample and then predicted the diagnosis of the left-out sample (jackknife method). Using a combination of the 10 best biomarkers, 15 of 17 samples were correctly diagnosed. Training the algorithm on time-resolved community profiles might provide a highly sensitive tool to detect the onset of periodontitis.
Immunization with the Entamoeba histolytica Surface Metalloprotease EhMSP-1 Protects Hamsters from Amebic Liver Abscess
Authors: Roncolato Eduardo C. , Teixeira José E. , Barbosa José E. , Zambelli Ramalho Leandra N. , Huston Christopher D.
Published: December 2014

Diarrhea and amebic liver abscesses due to invasiveEntamoeba histolyticainfections are an important cause of morbidity and mortality in the developing world.Entamoeba histolyticaadherence and cell migration, two phenotypes linked to virulence, are both aberrant in trophozoites deficient in the metallosurface protease EhMSP-1, which is a homologue of theLeishmaniavaccine candidate leishmanolysin (GP63). We examined the potential of EhMSP-1 for use as a vaccine antigen to protect against amebic liver abscesses. First, existing serum samples from South Africans naturally infected withE. histolyticawere examined by enzyme-linked immunosorbent assay (ELISA) for the presence of EhMSP-1-specific IgG. Nine of 12 (75%) people with anti-E. histolyticaIgG also had EhMSP-1-specific IgG antibodies. We next used a hamster model of amebic liver abscess to determine the effect of immunization with a mixture of four recombinant EhMSP-1 protein fragments. EhMSP-1 immunization stimulated a robust IgG antibody response. Furthermore, EhMSP-1 immunization of hamsters reduced development of severe amebic liver abscesses following intrahepatic injection ofE. histolyticaby a combined rate of 68% in two independent animal experiments. Purified IgG from immunized compared to control animals bound to the surface ofE. histolyticatrophozoites and accelerated amebic lysis via activation of the classical complement cascade. We concluded that EhMSP-1 is a promising antigen that warrants further study to determine its full potential as a target for therapy and/or prevention of invasive amebiasis.
THEMIS Is Required for Pathogenesis of Cerebral Malaria and Protection against Pulmonary Tuberculosis
Authors: Torre Sabrina , Faucher Sebastien P. , Fodil Nassima , Bongfen Silayuv E. , Berghout Joanne , Schwartzentruber Jeremy A. , Majewski Jacek , Lathrop Mark , Cooper Andrea M. , Vidal Silvia M. , Gros Philippe
Published: December 2014

We identify anN-ethyl-N-nitrosourea (ENU)-induced I23N mutation in the THEMIS protein that causes protection against experimental cerebral malaria (ECM) caused by infection withPlasmodium bergheiANKA.ThemisI23Nhomozygous mice show reduced CD4+and CD8+T lymphocyte numbers. ECM resistance inP. bergheiANKA-infectedThemisI23Nmice is associated with decreased cerebral cellular infiltration, retention of blood-brain barrier integrity, and reduced proinflammatory cytokine production. THEMISI23Nprotein expression is absent from mutant mice, concurrent with the decreased THEMISI23Nstability observedin vitro. Biochemical studiesin vitroand functional complementationin vivoinThemisI23N/+:Lck−/+doubly heterozygous mice demonstrate that functional coupling of THEMIS to LCK tyrosine kinase is required for ECM pathogenesis. Damping of proinflammatory responses inThemisI23Nmice causes susceptibility to pulmonary tuberculosis. Thus, THEMIS is required for the development and ultimately the function of proinflammatory T cells.ThemisI23Nmice can be used to study the newly discovered association ofTHEMIS(6p22.33) with inflammatory bowel disease and multiple sclerosis.
Characterization and Localization of the Campylobacter jejuni Transformation System Proteins CtsE, CtsP, and CtsX
Authors: Beauchamp Jessica M. , Erfurt Rebecca S. , DiRita Victor J.
Published: December 2014

The human pathogenCampylobacter jejuniis naturally competent for transformation with its own DNA. Genes required for efficient transformation inC. jejuniinclude those similar to components of type II secretion systems found in many Gram-negative bacteria (R. S. Wiesner, D. R. Hendrixson, and V. J. DiRita, J Bacteriol 185:5408–5418, 2003,http://dx.doi.org/10.1128/JB.185.18.5408-5418.2003). Two of these,ctsEandctsP, encode proteins annotated as putative nucleotide binding nucleoside triphosphatases (NTPases) or nucleoside triphosphate (NTP) binding proteins. Here we demonstrate that the nucleotide binding motifs of both proteins are essential for their function in transformation ofC. jejuni. Localization experiments demonstrated that CtsE is a soluble protein while CtsP is membrane associated inC. jejuni. A bacterial two-hybrid screen identified an interaction between CtsP and CtsX, an integral membrane protein also required for transformation. Topological analysis of CtsX by the use of LacZ and PhoA fusions demonstrated it to be a bitopic, integral membrane protein with a cytoplasmic amino terminus and a periplasmic carboxyl terminus. Notwithstanding its interaction with membrane-localized CtsX, CtsP inherently associates with the membrane, requiring neither CtsX nor several other Cts proteins for this association.
Recombinant Reporter Assay Using Transcriptional Machinery of Mycobacterium tuberculosis
Authors: Banerjee Rajdeep , Rudra Paulami , Saha Abinit , Mukhopadhyay Jayanta
Published: December 2014

Development of anin vivogene reporter assay to assess interactions among the components of the transcription machinery inMycobacterium tuberculosisremains a challenge to scientists due to the tediousness of generation of mutant strains of the extremely slow-growing bacterium. We have developed a recombinant mCherry reporter assay that enables us to monitor the interactions ofMycobacterium tuberculosistranscriptional regulators with its promotersin vivoinEscherichia coli. The assay involves a three-plasmid expression system inE. coliwherein two plasmids are responsible forM. tuberculosisRNA polymerase (RNAP) production and the third plasmid harbors the mCherry reporter gene expression cassette under the control of either a σ factor or a transcriptional regulator-dependent promoter. We observed that the endogenousE. coliRNAP and σ factor do not interfere with the assay. By using the reporter assay, we found that the functional interaction ofM. tuberculosiscyclic AMP receptor protein (CRP) occurs with its own RNA polymerase, not with theE. colipolymerase. Performing the recombinant reporter assay inE. coliis much faster than if performed inM. tuberculosisand avoids the hazard of handling the pathogenic bacterium. The approach could be expanded to develop reporter assays for other pathogenic and slow-growing bacterial systems.
Ethylmalonyl Coenzyme A Mutase Operates as a Metabolic Control Point in Methylobacterium extorquens AM1
Authors: Good Nathan M. , Martinez-Gomez N. Cecilia , Beck David A. C. , Lidstrom Mary E.
Published: December 2014

The metabolism of one- and two-carbon compounds by the methylotrophic bacterium
Methylobacterium extorquens
AM1 involves high carbon flux through the ethylmalonyl coenzyme A (ethylmalonyl-CoA) pathway (EMC pathway). During growth on ethylamine, the EMC pathway operates as a linear pathway carrying the full assimilatory flux to produce glyoxylate, malate, and succinate. Assimilatory carbon enters the ethylmalonyl-CoA pathway directly as acetyl-CoA, bypassing pathways for formaldehyde oxidation/assimilation and the regulatory mechanisms controlling them, making ethylamine growth a useful condition to study the regulation of the EMC pathway. Wild-type
M. extorquens
cells were grown at steady state on a limiting concentration of succinate, and the growth substrate was then switched to ethylamine, a condition where the cell must make a sudden switch from utilizing the tricarboxylic acid (TCA) cycle to using the ethylmalonyl-CoA pathway for assimilation, which has been an effective strategy for identifying metabolic control points. A 9-h lag in growth was observed, during which butyryl-CoA, a degradation product of ethylmalonyl-CoA, accumulated, suggesting a metabolic imbalance. Ethylmalonyl-CoA mutase activity increased to a level sufficient for the observed growth rate at 9 h, which correlated with an upregulation of RNA transcripts for
ecm
and a decrease in the levels of ethylmalonyl-CoA. When the wild-type strain overexpressing
ecm
was tested with the same substrate switchover experiment, ethylmalonyl-CoA did not accumulate, growth resumed earlier, and, after a transient period of slow growth, the culture grew at a higher rate than that of the control. These findings demonstrate that ethylmalonyl-CoA mutase is a metabolic control point in the EMC pathway, expanding our understanding of its regulation.
New Tools for Comparing Microscopy Images: Quantitative Analysis of Cell Types in Bacillus subtilis
Authors: van Gestel Jordi , Vlamakis Hera , Kolter Roberto
Published: December 2014

Fluorescence microscopy is a method commonly used to examine individual differences between bacterial cells, yet many studies still lack a quantitative analysis of fluorescence microscopy data. Here we introduce some simple tools that microbiologists can use to analyze and compare their microscopy images. We show how image data can be converted to distribution data. These data can be subjected to a cluster analysis that makes it possible to objectively compare microscopy images. The distribution data can further be analyzed using distribution fitting. We illustrate our methods by scrutinizing two independently acquired data sets, each containing microscopy images of a doubly labeled
Bacillus subtilis
strain. For the first data set, we examined the expression of
srfA
and
tapA
, two genes which are expressed in surfactin-producing and matrix-producing cells, respectively. For the second data set, we examined the expression of
eps
and
tapA
; these genes are expressed in matrix-producing cells. We show that
srfA
is expressed by all cells in the population, a finding which contrasts with a previously reported bimodal distribution of
srfA
expression. In addition, we show that
eps
and
tapA
do not always have the same expression profiles, despite being expressed in the same cell type: both operons are expressed in cell chains, while single cells mainly express
eps
. These findings exemplify that the quantification and comparison of microscopy data can yield insights that otherwise would go unnoticed.