Cervical length for prediction of preterm birth in women with multiple prior induced abortions

OBJECTIVE

To determine whether transvaginal sonographic cervical length predicts preterm birth in women with multiple prior induced abortions.

METHODS

This was a retrospective cohort study using the Thomas Jefferson University Prematurity Database. Patients with a singleton pregnancy and a history of more than one induced abortion were identified. Exclusion criteria were cerclage and indicated preterm birth. Subjects were followed with transvaginal ultrasound measurement of the cervix between 14 and 24 weeks' gestation and grouped into those with and those without a short cervix; a cervical length of < 25 mm was considered short. The primary outcome was spontaneous preterm birth at < 35 weeks.

RESULTS

Fifteen of the 65 (23%) women with more than one induced abortion included in the study had a short cervix. The demographics and risk factors were similar between those with and those without a short cervix. The overall incidence of preterm birth was 21.5% (14/65); in women with a short cervix the incidence was 47% (7/15) and in women without a short cervix it was 14% (7/50). The sensitivity, specificity and positive and negative predictive values of a short cervix in the prediction of preterm birth were 50%, 84%, 47% and 86%, respectively. The relative risk of a short cervix for spontaneous preterm birth was 3.3 (95% CI, 1.4-7.4).

CONCLUSION

A cervical length of < 25 mm on transvaginal ultrasound is predictive of preterm birth in women with more than one prior induced abortion. Women with multiple prior induced abortions and a short cervix have a 3.3-fold greater chance of spontaneous preterm birth compared with those with a cervical length of > or = 25mm.

The degradation of the herbicide bromoxynil and its impact on bacterial diversity in a top soil

AIMS

To study how repeated applications of an herbicide bromoxynil to a soil, mimicking the regime used in the field, affected the degradation of the compound and whether such affects were reflected by changes in the indigenous bacterial community present.

METHODS AND RESULTS

Bromoxynil degradation was monitored in soil microcosms using HPLC. Its impact on the bacterial community was determined using denaturing gradient gel electrophoresis (DGGE) and quantitative PCR of five bacterial taxa (Pseudomonads, Actinobacteria, alpha-Proteobacteria, Acidobacteria and nitrifying bacteria). Three applications of 10 mg kg(-1) of bromoxynil at 28-day intervals resulted in rapid degradation, the time for removal of 50% of the compound decreasing from 6.4 days on the first application to 4.9 days by the third. Bacterial population profiles showed significant similarity throughout the experiment. With the addition of 50 mg kg(-1) bromoxynil to soil, the degradation was preceded by a lag phase and the time for 50% of the compound to be degraded increased from 7 days to 28 days by the third application. The bacterial population showed significant differences 7 days after the final application of bromoxynil that correlated with an inhibition of degradation during the same period.

CONCLUSIONS

These analyses highlighted that the addition of bromoxynil gave rise to significant shifts in the community diversity and its structure as measured by four abundant taxa, when compared with the control microcosm. These changes persisted even after bromoxynil had been degraded.

SIGNIFICANCE AND IMPACT OF THE STUDY

Here we show that bromoxynil can exert an inhibitory effect on the bacterial population that results in decreased rates of degradation and increased persistence of the compound. In addition, we demonstrate that molecular approaches can identify statistically significant changes in microbial communities that occur in conjunction with changes in the rate of degradation of the compound in the soil.

The application of the herbicide bromoxynil to a model soil-derived bacterial community: impact on degradation and community structure

AIMS

Bromoxynil degradation by soil micro-organisms has been shown to be co-oxidative in character. In this study, we investigate both the impact of the application of increasing bromoxynil concentrations on soil-derived bacterial communities and how these changes are reflected in the degradation of the compound. Our aim was to test the hypothesis that the addition of bromoxynil to a soil-derived bacterial community, and the availability of a readily utilizable carbon source would have an impact on bromoxynil degradation, and that would be reflected in the bacteria present in the soil community.

METHODS AND RESULTS

Degradation of bromoxynil was observed in soil-derived communities containing 15 mg l(-1), but not 50 mg l(-1) of the compound, unless glucose was added. This suggests that the addition of carbon stimulates co-oxidative bromoxynil degradation by the members of the bacterial community. Measurable changes in the bacterial community indicated that the addition of bromoxynil led to deterministic selection on the bacterial population, i.e. the communities observed arise through the selection of specific micro-organisms that are best adapted to the conditions in the soil. The addition of bromoxynil was also shown to have a negative impact on the presence of alpha and gamma-proteobacteria in the soil community.

CONCLUSION

Bromoxynil degradation is significantly inhibited in bacterial soil communities in the absence of readily accessible carbon. The application of bromoxynil appears to exert deterministic selection on the bacterial community.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study highlights the effects of increasing bromoxynil concentrations on a model bacterial population derived from soil. Soil communities show qualitative and quantitative differences to bromoxynil application depending on the availability of organic carbon. These findings might have implications for the persistence of bromoxynil in agricultural soils.

The impact of acrylonitrile and bioaugmentation on the biodegradation activity and bacterial community structure of a topsoil

The analysis of the bacterial community within the soil using DGGE showed acrylonitrile (ACN) could lead to the selection of significantly similar communities. Moreover, Rhodococcus sp. AJ270 was successfully established in the soil community. High GC G+-bacteria also responded positively to ACN addition. Bioaugmentation or carbon addition had no impact on the rate or degree of ACN degradation. ACN could be readily degraded by the soil bacteria, however, the community structure was significantly affected by its addition as well as by the addition of carbon or Rhodococcus sp. AJ270. The bioaugmentation of the soil with this strain was successful, in that the organism became established within the community. ACN addition to a soil produces statistically significant changes in the bacterial community.

The Impact of Bioaugmentation on Metal Cyanide Degradation and Soil Bacteria Community Structure

Metal cyanides are significant contaminants of many soils found at the site of former industrial activity. In this study we isolated bacteria capable of degrading ferric ferrocyanide and K2Ni(CN)4. One of these bacteria a Rhodococcus spp. was subsequently used to bioaugment a minimal medium broth, spiked with K2Ni(CN)4, containing 1 g of either an uncontaminated topsoil or a former coke works site soil. Degradation of the K2Ni(CN)4 was observed in both soils, however, bioaugmentation did not significantly impact the rate or degree of K2Ni(CN)4 removal. Statistical analysis of denaturing gradient gel electrophoresis profiles showed that the topsoil bacterial community had a higher biodiversity, and its structure was not significantly affected by either K2Ni(CN)4 or bioaugmentation. In contrast, profiles from the coke works site indicated significant changes in the bacterial community in response to these additions. Moreover, in both soils although bioaugmentation did not affect rates of biodegradation the Rhodococcus spp. did become established in the communities in broths containing both top and coke works soil. We conclude that bacterial communities from contaminated soils with low biodiversity are much more readily perturbed through interventions such as contamination events or bioaugmentation treatments and discuss the implications of these findings for bioremediation studies.

Pneumococcal vaccination during pregnancy for preventing infant infection

BACKGROUND

Each year at least one million children worldwide die of pneumococcal infections. The development of bacterial resistance to antimicrobials adds to the difficulty of treatment of diseases and emphasizes the need for a preventive approach. Newborn vaccination schedules could substantially reduce the impact of pneumococcal disease in immunized children, but does not have an effect on the morbidity and mortality of infants less than three months of age. Pneumococcal vaccination during pregnancy may be a way of preventing pneumococcal disease during the first months of life before the pneumococcal vaccine administered to the infant starts to produce protection.

OBJECTIVES

To assess the effect of pneumococcal vaccination during pregnancy for preventing infant infection.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group Trials Register (June 2004), CENTRAL (The Cochrane Library, Issue 2, 2004), MEDLINE (January 1966 to June 2004), EMBASE (January 1985 to June 2004), and reference lists of articles.

SELECTION CRITERIA

Randomized controlled trials in pregnant women comparing pneumococcal vaccine with placebo or doing nothing or with another vaccine to prevent infant infections.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed methodological quality and extracted data using a data collection form. Study authors were contacted for additional information.

MAIN RESULTS

Three trials (280 participants) were included. There was no evidence that pneumococcal vaccination during pregnancy reduces the risk of neonatal infection (one trial, 149 pregnancies, relative risk (RR) 0.51; 95% confidence interval (CI) 0.18 to 1.41). Although the data suggest an effect in reducing pneumococcal colonisation in infants by 16 months of age (one trial, 56 pregnancies, RR 0.33; 95% CI 0.11 to 0.98), there was no evidence of this effect in infants at two months of age (RR 0.28; 95% CI 0.02 to 5.11) or by seven months of age (RR 0.32; 95% CI 0.08 to 1.29).

AUTHORS' CONCLUSIONS

There is insufficient evidence to support whether pneumococcal vaccination during pregnancy could reduce infant infections.

Analysis of the evolution of granular stress-strain and voidage states based on DEM simulations

We review and discuss the results of our granular-dynamics simulations of the time evolution of the microstructure of compact granular beds as found in pouring, in hopper filling and discharge, and in a shear cell. These systems are mainly quasi-static. However, it is also common to encounter localized 'shear zones' with significant velocity/voidage fluctuations and high bulk-strain gradients. These narrow-banded zones are separated from near-static regions by sharp, discontinuous changes of bulk stress and voidage. Within these bands the granular assembly undergoes a transition from the quasi-static to the inertial state, where enduring particle contacts are increasingly replaced by collisional ones. We focus on the discrete particle origins of this inhomogeneous yield/flow behaviour. We show the usefulness of analysing the local evolution in terms of relative rotation of the grains which is observed to cause rapid local bulk dilation responsible for setting off avalanches near free-surface boundaries and protracted bulk-failure planes in confined static assemblies. We also present some evidence to suggest that allowing for effective continuous particle-particle interactions could approximate observed effects attributable to particle shape and surface roughness. Wavelet analyses have been applied successfully to generate the variations in periodicity and the relative sequence of evolution of the stress, strain-rate and voidage states in avalanching granular heaps and in the wall region of axially symmetric hopper flows.

Discrete-element method simulations: from micro to macro scales

Many liquid systems encountered in environmental science are often complex mixtures of many components which place severe demands on traditional computational modelling techniques. A meso scale description is required to account adequately for their flow behaviour on the meso and macro scales. Traditional techniques of computational fluid dynamics and molecular simulation are not well suited to tackling these systems, and researchers are increasingly turning to a range of relatively new computational techniques that offer the prospect of addressing the factors relevant to multicomponent multiphase liquids on length- and time-scales between the molecular level and the macro scale. In this category, we discuss the off-lattice techniques of 'smooth particle hydrodynamics' (SPH) and 'dissipative particle dynamics' (DPD), and the grid-based techniques of 'lattice gas' and 'lattice Boltzmann' (LB). We highlight the main conceptual and technical features underpinning these methods, their strengths and weaknesses, and provide a few examples of the applications of these techniques that illustrate their utility.

Competition for attachment of aquaculture candidate probiotic and pathogenic bacteria on fish intestinal mucus

Probiotics for aquaculture are generally only selected by their ability to produce antimicrobial metabolites; however, attachment to intestinal mucus is important in order to remain within the gut of its host. Five candidate probiotics (AP1-AP5), isolated from the clownfish, Amphiprion percula (Lacepéde), were examined for their ability to attach to fish intestinal mucus and compete with two pathogens, Aeromonas hydrophila and Vibrio alginolyticus. Two different radioactive isotopes were used to quantify competition between pathogens and probionts. Attachment of the pathogens was enhanced by the presence of the candidate probiotics. However, the addition of the candidate probiotics after the pathogens resulted in reduced pathogen attachment. Only AP5 caused lower attachment success of V. alginolyticus when added before the pathogen. When AP5 was added first, the average attachment change was 41% compared with 72% when added after V. alginolyticus, suggesting that the probiotic is displaced but that enhanced attachment of the pathogen does not occur. Conversely, when V. alginolyticus was added first, followed by AP5, attachment change was 37% while AP5 had 92% attachment change when added second. This implies that the pathogen was displaced by the candidate probiotic and therefore it appeared that, based on the ability of probiont AP5 to attach to mucus, the growth of the pathogen in the digestive tract might be suppressed by the candidate probiont's presence.

Insulin resistance as a modifier of the relationship between dietary fat intake and weight gain

OBJECTIVE

To investigate whether insulin resistance modifies the rate of weight gain associated with a high percent of energy intake from dietary fat.

DESIGN

Longitudinal, observational population study.

SUBJECTS

A total of 782 nondiabetic Hispanic and non-Hispanic white free-living adult residents of the San Luis Valley in Colorado.

MEASUREMENTS

Subjects were seen up to three times over a 14-y period. Weight, height, fasting insulin and glucose, diet by 24 h recall, and self-reported physical activity were collected at each visit.

RESULTS

Percentage of energy intake from dietary fat was positively associated with weight gain over time (P=0.0103). High intake of dietary fat was more strongly related to weight gain in women than in men, and in those with lower total energy intake levels. The relationship between weight change and relative macronutrient intake also varied by baseline insulin sensitivity (P=0.0025). Weight gain over time in individuals with relative insulin resistance at baseline, as measured by QUICKI, was the greatest among those who consumed a higher percent of energy from fat.

CONCLUSION

Percentage of total intake from dietary fat predicts weight change independent of total energy intake. Nondiabetic, insulin-resistant individuals are particularly susceptible to the weight gain associated with high levels of dietary fat intake. Further investigation into the relationship between insulin resistance, diet, and weight gain is warranted.

Trusting technology: women aged 40-49 years participating in screening for breast cancer--an exploratory study

OBJECTIVE

This paper reports key findings from an exploratory study of factors associated with women's decision to participate in mass mammography screening in Tasmania. In particular, we explored factors that contribute to the choice to participate in screening by women who are outside the primary target group, and for whom the evidence of benefit remains contentious.

METHODS

Semi-structured interviews were conducted with a small sample of women aged between 40 and 49 years in rural Tasmania who had participated in mammography screening.

RESULTS

Key ideas that appeared to shape participation included the fear of breast cancer, trust in technology, and taking responsibility for health. Information provision is also an important factor in shaping participation patterns.

CONCLUSIONS AND IMPLICATIONS

In order to facilitate informed consent, information provision in this area should take account of the dominant ideas that shape the decision to participate in breast cancer screening.

Eight years' experience of gastrostomy tube management

BACKGROUND AND STUDY AIMS

Increasingly, patients fed by gastrostomy tube are surviving the lifespan of the device. Data are scarce concerning the factors affecting the longevity and failure of gastrostomy tubes or the criteria for selection of replacement devices which leads to cost-effective patient management. The aims of the study were: to set criteria for selection of replacement gastrostomy tubes; to determine the causes of gastrostomy tube failure, and the factors affecting device longevity; and to examine the effect of initiating an educational programme for caregivers on resource utilization in long-term enteral nutrition patients.

MATERIALS AND METHODS

We analyzed the clinical gastrostomy tube database compiled prospectively over 8 years by the nutrition team at Ninewells Hospital, Dundee.

RESULTS

For 363 gastrostomy tubes inserted in 304 patients (160 women; median age 71), the median duration of gastrostomy tube use was 138 days. The total follow-up was 294 patient-years. Death occurred before the first gastrostomy tube replacement in 48 % of patients, but 20 % resumed oral nutrition. Tube failure mechanisms were: dislodgment, 28 %; perishing of tube material, 25 %; tube-related Candida albicans infection, 16 %; leakage, 7 %; and unspecified, 7 %. Of the balloon tubes and gastrostomy buttons, 8 % needed early replacement due to dislodgment and/or leakage. The cost per day for replacement percutaneous endoscopic gastrostomy (PEG) was Euro 2.12, for balloon tubes it was Euro 0.62, and for gastrostomy buttons Euro 1.80. Despite an increasing PEG insertion rate throughout the study period, yearly referrals for PEG-related problems dropped by 30 % between 1997 to 1999, coinciding with the initiation of an educational programme for caregivers.

CONCLUSION

Tube longevity is mainly limited by the patient's diagnosis and prognosis. The choice of replacement device should be based on clinical factors. The use of more durable materials in the manufacture of gastrostomy tubes may prolong tube life and reduce cost. Education of patients and caregivers by a multidisciplinary nutrition support team promotes independence and limits demand on the service.

Are Maori under-served for cardiac interventions?

AIMS

To examine hospitalisation rates for selected heart-disease-related diagnoses by age, gender, ethnicity and deprivation.

METHODS

Four years' data on publicly-funded hospital discharges for: (i) heart failure and (ii) cardiac interventions were cross-classified by age group, gender, ethnicity (Maori/non-Maori) and deprivation (NZDep96). Population hospitalisation rates were calculated and displayed in multi-dimensional trellis graphs.

RESULTS

The graphs show patterns of hospitalisation for chosen variables simultaneously. The expected increase in heart failure with age is found, as is an increase for the cardiac group up to ages 65-74 years. Clear gender differences were found. A further increase of heart failure with higher deprivation is evident throughout. For cardiac interventions, the relationship with deprivation is complex. Differences by ethnicity are disturbing. Hospitalisation rates for heart failure for Maori are typically more than double the non-Maori rates. In contrast, for the cardiac group Maori intervention rates are much lower.

CONCLUSIONS

Graphical analysis that displays age, gender, ethnicity and deprivation simultaneously provides great insight into hospitalisation rates. Ethnic differences are particularly concerning and raise important questions about how well Maori needs are being met and how equitable is access to cardiac interventions for Maori.

Infinite-Horizon Policy-Gradient Estimation

Gradient-based approaches to direct policy search in reinforcement learning have received much recent attention as a means to solve problems of partial observability and to avoid some of the problems associated with policy degradation in value-function methods. In this paper we introduce GPOMDP, a simulation-based algorithm for generating a biased estimate of the gradient of the average reward in Partially Observable Markov Decision Processes POMDPs controlled by parameterized stochastic policies. A similar algorithm was proposed by (Kimura et al. 1995). The algorithm's chief advantages are that it requires storage of only twice the number of policy parameters, uses one free beta (which has a natural interpretation in terms of bias-variance trade-off), and requires no knowledge of the underlying state. We prove convergence of GPOMDP, and show how the correct choice of the parameter beta is related to the mixing time of the controlled POMDP. We briefly describe extensions of GPOMDP to controlled Markov chains, continuous state, observation and control spaces, multiple-agents, higher-order derivatives, and a version for training stochastic policies with internal states. In a companion paper (Baxter et al., this volume) we show how the gradient estimates generated by GPOMDP can be used in both a traditional stochastic gradient algorithm and a conjugate-gradient procedure to find local optima of the average reward.