A galactose-specific sugar: phosphotransferase permease is prevalent in the non-core genome of Streptococcus mutans

Three genes predicted to encode the A, B and C domains of a sugar : phosphotransferase system (PTS) permease specific for galactose\(EII(Gal) ) were identified in the genomes of 35 of 57 recently sequenced isolates of Streptococcus mutans, the primary etiological agent of human dental caries. Mutants defective in the EII(Gal) complex were constructed in six of the isolates and showed markedly reduced growth rates on galactose-based medium relative to the parental strains. An EII(Gal) -deficient strain constructed using the invasive serotype f strain OMZ175 (OMZ/IIGal) expressed significantly lower PTS activity when galactose was present as the substrate. Galactose was shown to be an effective inducer of catabolite repression in OMZ175, but not in the EII(Gal) -deficient strain. In a mixed-species competition assay with galactose as the sole carbohydrate source, OMZ/IIGal was less effective than the parental strain at competing with the oral commensal bacterium Streptococcus gordonii, which has a high-affinity galactose transporter. Hence, a significant proportion of S. mutans strains encode a galactose PTS permease that could enhance the ability of these isolates to compete more effectively with commensal streptococci for galactose in salivary constituents and the diet.

Observation of a critical gradient threshold for electron temperature fluctuations in the DIII-D Tokamak

A critical gradient threshold has been observed for the first time in a systematic, controlled experiment for a locally measured turbulent quantity in the core of a confined high-temperature plasma. In an experiment in the DIII-D tokamak where L(T(e))(-1) = |∇T(e)|/T(e) and toroidal rotation were varied, long wavelength (k(θ)ρ(s) ≲ 0.4) electron temperature fluctuations exhibit a threshold in L(T(e))(-1): below, they change little; above, they steadily increase. The increase in δT(e)/T(e) is concurrent with increased electron heat flux and transport stiffness. Observations were insensitive to rotation. Accumulated evidence strongly enforces the identification of the experimentally observed threshold with ∇T(e)-driven trapped electron mode turbulence.

The added challenges of bone metastases treatment in elderly patients

Most cancers occur in those older than the age of 65 years. As the population of the world ages and life expectancies continue to increase, it is important to address treatment challenges for elderly patients. This narrative review details the challenges of palliative radiotherapy treatment for elderly patients with bone metastases. We begin with the definition of elderly and its appropriateness, outlining recent demographic data of patients with cancer. The current status of elderly participation in clinical trials is discussed by reviewing the recent literature and clinical trial data. Factors affecting enrolment of the elderly are assessed, with a focus on palliative radiotherapy trials, and what we can do to improve accrual in this data-driven setting. At present, there is a lack of level 1 evidence that evaluates the optimal treatment for elderly patients with bone metastases. Therefore, a review of safety and efficacy is given based on previously published reports. Palliative radiotherapy for elderly patients is a worthwhile treatment and should be recommended regardless of age, as supported by available evidence. Patient, family and physician concerns about physical burden may be reduced as single treatments (that often can be done in a single visit) are as beneficial as multiple treatments for painful bone metastases. In elderly patients, radiotherapy may even be the best treatment for these cases as opioid-related adverse events are amplified in this group and often dosages are more difficult to titrate. Clinicians should continue to encourage the enrolment of elderly patients on to clinical trials as these data form the basis of optimal treatment guidelines. Radiation oncologists are encouraged to reduce the physical burden for elderly patients by offering single treatments where appropriate and completing consultation, treatment simulation and treatment in a single clinical visit.

Design of a millimeter-wave polarimeter for NSTX-Upgrade and initial test on DIII-D

Polarimetry is a powerful diagnostic technique to probe plasma equilibria and magnetic fluctuations in fusion plasmas. In a high beta plasma such as the National Spherical Torus eXperiment (NSTX), these measurements are important to understand plasma stability and anomalous transport. A 288 GHz polarimeter operating along a major radial chord in retroreflection geometry has been developed and is being tested on the DIII-D tokamak to prepare for future implementation on NSTX-Upgrade. The system launches a rotating linearly polarized beam and detects the phase shift directly related to the polarization change caused by the plasma. To accomplish this, a pair of orthogonal linearly polarized beams with a stable difference frequency is generated using a single sideband modulation technique, then combined and transformed to be counter-rotating circularly polarized. To improve phase resolution, quasi-optical isolation, using Faraday rotators and polarizers, is utilized to eliminate a multi-path feedback effect, which is found to be the primary source of phase error. The bench tests in the laboratory and DIII-D power supply test discharges indicate ≤1° phase resolution.

Inter-rater reliability between musculoskeletal radiologists and orthopedic surgeons on computed tomography imaging features of spinal metastases

INTRODUCTION

The primary objective of this pilot study was to examine the inter-rater reliability in scoring the computed tomography (ct) imaging features of spinal metastases in patients referred for radiotherapy (rt) for bone pain.

METHODS

In a retrospective review, 3 musculoskeletal radiologists and 2 orthopedic spinal surgeons independently evaluated ct imaging features for 41 patients with spinal metastases treated with rt in an outpatient radiation clinic from January 2007 to October 2008. The evaluation used spinal assessment criteria that had been developed in-house, with reference to osseous and soft tissue tumour extent,presence of a pathologic fracture,severity of vertebral height loss, andpresence of kyphosis.The Cohen kappa coefficient between the two specialties was calculated.

RESULTS

Mean patient age was 69.2 years (30 men, 11 women). The mean total daily oral morphine equivalent was 73.4 mg. Treatment dose-fractionation schedules included 8 Gy/1 (n = 28), 20 Gy/5 (n = 12), and 20 Gy/8 (n = 1). Areas of moderate agreement in identifying the ct imaging appearance of spinal metastasis included extent of vertebral body involvement (κ = 0.48) and soft-tissue component (κ = 0.59). Areas of fair agreement included extent of pedicle involvement (κ = 0.28), extent of lamina involvement (κ = 0.35), and presence of pathologic fracture (κ = 0.20). Areas of poor agreement included nerve-root compression (κ = 0.14) and vertebral body height loss (κ = 0.19).

CONCLUSIONS

The range of agreement between musculoskeletal radiologists and orthopedic surgeons for most spinal assessment criteria is moderate to poor. A consensus for managing challenging vertebral injuries secondary to spinal metastases needs to be established so as to best triage patients to the most appropriate therapeutic modality.

Involvement of decreased hypoxia-inducible factor 1 activity and resultant G1-S cell cycle transition in radioresistance of perinecrotic tumor cells

Cancer patients often suffer from local tumor recurrence after radiation therapy. Some intracellular and extracellular factors, such as activity of hypoxia-inducible factor 1 (HIF-1), cell cycle status and oxygen availability, have been suggested to affect DNA damage responses and eventual radioresistant characteristics of cancer cells. But when, where, and how these factors affect one another and induce cellular radioresistance is largely unknown. Here, we analyzed mechanistic and spatio-temporal relationships among them in highly heterogeneous tumor microenvironments. Experiments in vitro demonstrated that a decrease in the glucose concentration reduced the transcriptional activity of HIF-1 and expression of a downstream gene for the cell cycle regulator p27^Kip1 even under hypoxic conditions. Then, the proportion of cells in the radioresistant S phase increased, whereas that in the radiosensitive G₁ phase decreased, significantly. Immunohistochemical analyses showed that cancer cells in perinecrotic hypoxic regions, which should be under low-glucose conditions, expressed little HIF-1α, and therefore, were mainly in S phase and less damaged by radiation treatment. Continuous administration of glucagon, which increases the blood glucose concentration and so improves glucose availability in perinecrotic hypoxic regions, induced HIF-1α expression and increased radiation-induced DNA damage. Taken all together, these results indicate that cancer cells in perinecrotic regions, which would be under low-glucose and hypoxic conditions, obtain radioresistance by decreasing the level of both HIF-1 activity and p27^Kip1 expression, and adjusting their cell cycle to the radioresistant S phase.

Role of zonal flow predator-prey oscillations in triggering the transition to H-mode confinement

Direct evidence of zonal flow (ZF) predator-prey oscillations and the synergistic roles of ZF- and equilibrium E×B flow shear in triggering the low- to high-confinement (L- to H-mode) transition in the DIII-D tokamak is presented. Periodic turbulence suppression is first observed in a narrow layer at and just inside the separatrix when the shearing rate transiently exceeds the turbulence decorrelation rate. The final transition to H mode with sustained turbulence and transport reduction is controlled by equilibrium E×B shear due to the increasing ion pressure gradient.

[Isolation and identification of Citrobacter freundii from diseased giant salamander, Andrias davidianus]

OBJECTIVE

To determine the pathogenic bacterium infecting giant salamander (Andrias davidianus).

METHODS

Bacterium was isolated from the liver of diseased Chinese giant salamander and identified by the Biolog Microbial Identification System and molecular biology method. Healthy Chinese giant salamander and crucian carp were used for experimental infection with bacterial suspension.

RESULTS

A bacterial strain JZ01 was isolated and identified from diseased giant salamander. Infection with the bacterial suspension to healthy giant salamander could reproduce the diseased symptoms as occurred naturally and the same bacterium could be recovered from these infected giant salamanders. The isolated bacterium also has certain pathogenicity to crucian carp. Identification by the Biolog Microbial Identification System, and further 16S rDNA sequence and phylogenetic analysis demonstrated that the bacterium isolated from diseased giant salamander was Citrobacter freundii. The susceptibility test to antibiotics demonstrated that the bacterial strain JZ01 was susceptible to aztreonam, cefepime and cefotamine.

CONCLUSION

Citrobacter freundii is a pathogen for cultured Chinese giant salamander.

Association of β-cell function and insulin sensitivity with fasting and 2-h plasma glucose in a large Chinese population

AIM

Our aim was to provide a quantitative analysis of the changes in the principal determinants of insulin sensitivity and secretion in relation to fasting plasma glucose (FPG) or 2-h plasma glucose (2h PG) in a Chinese population with a wide range of glucose tolerance.

METHODS

A total of 5728 adults spanning the entire range of glucose tolerance were included. Insulin sensitivity was measured by Matsuda insulin sensitivity index (ISI(M)) and homeostasis model assessment of 1/homeostasis model assessment of insulin resistance (HOMA-IR). β-Cell function adjusted by insulin sensitivity was assessed from disposition index (DI) at early-phase DI(30) and total DI(120). The exponential curve was established as the best fit for the relationship between insulin sensitivity or β-cell function and FPG or 2h PG.

RESULTS

Relative to the trend classified as increasing 2h PG, hepatic insulin sensitivity and insulin secretion showed a decreasing trend to a substantial degree as FPG increased. A 1 mmol/l increase in FPG and 2h PG concentration was associated with a -22 and -21% decline in ISI(M), -16 and -4% in 1/HOMA-IR, -38 and -35% in DI(30) and -36 and -26% in DI(120). The decay constant of ISI(M) and DI(30) in IFG or ISI(M), 1/HOMA-IR, DI(30) and DI(120) in IGT was lower than that in normal glucose tolerance. Significant interactions between sex and glucose levels determining DI were found.

CONCLUSIONS

We conclude that impairment of insulin sensitivity and insulin secretion contributes to both FPG or 2h PG hyperglycaemia in a Chinese population, but that the decline in insulin secretion is more pronounced with increasing fasting than 2h PG.

A Bayesian approach to risk-adjusted outcome monitoring in healthcare

Clinical outcomes are commonly monitored in healthcare practices to detect changes in care providers' performance. One key challenge in outcome monitoring is the need of adjustment for patient base-line risks. Various control charting methods have been developed to conduct risk-adjusted outcome monitoring, but they all rely on the availability of a large number of historical data. We propose a Bayesian approach to this type of monitoring for cases where historical data are not available. In our approach, detection of change is formulated as a model-selection problem and solved using a popular Bayesian tool for variable selection, the Bayes factor. Issues in decision-making about whether there is a change point in the observed patient outcomes are addressed, including specification of priors and computation of Bayes factors. This approach is applied to a real data set on cardiac surgeries, and its performance under different parameter scenarios is studied through simulations.

Update on the systematic review of palliative radiotherapy trials for bone metastases

AIMS

To update previous meta-analyses of randomised palliative radiotherapy trials comparing single fractions versus multiple fractions.

MATERIALS AND METHODS

All published randomised controlled trials comparing single fraction versus multiple fraction schedules for the palliation of uncomplicated bone metastases were included in this analysis. Odds ratios and 95% confidence intervals were calculated for each trial. Forest plots were created using a random effects model and the Mantel-Haenszel statistic.

RESULTS

In total, 25 randomised controlled trials were identified. For intention-to-treat patients, the overall response rate was similar in patients receiving single fractions (1696 of 2818; 60%) and multiple fractions (1711 of 2799; 61%). Complete response rates were 620 of 2641 (23%) in the single fraction arm and 634 of 2622 (24%) in the multiple fraction arm. No significant difference was seen in overall or complete response rates. Pathological fracture did not favour either arm, but spinal cord compression trended towards favouring multiple fractions; however, neither was statistically significant (P = 0.72 and P = 0.13, respectively). Retreatment rates favoured patients in the multiple fraction arm, where the likelihood of requiring re-irradiation was 2.6-fold greater in the single fraction arm (95% confidence interval: 1.92-3.47; P < 0.00001). Repeated analyses excluding drop-out patients did not alter these findings. In general, no significant differences in acute toxicities were seen.

CONCLUSION

Overall and complete response rates were similar in both intention-to-treat and assessable patients. Single and multiple fraction regimens provided equal pain relief; however, significantly higher retreatment rates occurred in those receiving single fractions.

Assessment of health-related quality of life with the European Organization for Research and Treatment of Cancer QLQ-C15-PAL after palliative radiotherapy of bone metastases

AIMS

To assess health-related quality of life (HRQOL) after palliative radiotherapy for painful bone metastases using a palliative questionnaire (European Organization for Research and Treatment of Cancer QLQ-C15-PAL).

MATERIALS AND METHODS

Patients scheduled to receive palliative radiotherapy for painful bone metastases (n=178) completed the QLQ-C15-PAL questionnaire before treatment and at week 1, week 2, month 1 and month 2 after the first day of radiotherapy. A partial response (PR) or a complete response (CR) to radiotherapy was defined according to the International Consensus criteria. General linear regression was used to analyse changes in QOL in the entire cohort and within responders and non-responders to radiotherapy at all follow-up periods.

RESULTS

The overall radiotherapy response was 45% at week 1 (n=21) (41% PR, 4% CR), 62% at week 2 (n=28) (58% PR, 4% CR), 62% at month 1 (n=58) (60% PR, 2% CR) and 65% at month 2 (n=38) (60% PR, 5% CR). In general, a significant decrease in pain (P<0.0001), insomnia (P<0.0001) and constipation (P=0.004) was seen by month 1 after radiotherapy. In patients who responded to radiotherapy, overall QOL significantly improved by month 2 after radiotherapy (P=0.002). Radiotherapy responders also reported an improvement in emotional functioning together with a decrease in symptoms such as insomnia and constipation at month 1. No improvements were seen in any of the QLQ-C15-PAL scores for patients whose pain did not respond to radiotherapy.

CONCLUSION

Radiotherapy responders showed not only an improvement in pain, but also in HRQOL as assessed by QLQ-C15-PAL. As early as 1 week after radiotherapy for bone metastases, a pain relief response was reported by patients.