Sensing Levofloxacin with an RNA Aptamer as a Bioreceptor

To combat the growing threat of antibiotic resistance, environmental testing for antibiotic contamination is gaining an increasing role. This study aims to develop an easy-to-use assay for the detection of the fluoroquinolone antibiotic levofloxacin. Levofloxacin is used in human and veterinary medicine and has been detected in wastewater and river water. An RNA aptamer against levofloxacin was selected using RNA Capture-SELEX. The 73 nt long aptamer folds into three stems with a central three-way junction. It binds levofloxacin with a Kd of 6 µM and discriminates the closely related compound ciprofloxacin. Furthermore, the selection process was analyzed using a next-generation sequencing approach to better understand the sequence evolution throughout the selection. The aptamer was used as a bioreceptor for the development of a lateral flow assay. The biosensor exploited the innate characteristic of RNA Capture-SELEX to select aptamers that displace a complementary DNA oligonucleotide upon ligand binding. The lateral flow assay achieved a limit of visual detection of 100 µM. While the sensitivity of this assay constrains its immediate use in environmental testing, the present study can serve as a template for the selection of RNA aptamer-based biosensors.

Visual attentional guidance during smooth pursuit eye movements: Distractor interference is independent of distractor-target similarity

In the current study, we used abrupt-onset distractors similar and dissimilar in luminance to the target of a smooth pursuit eye-movement to test if abrupt-onset distractors capture attention in a top-down or bottom-up fashion while the eyes track a moving object. Abrupt onset distractors were presented at different positions relative to the current position of a pursuit target during the closed-loop phase of smooth pursuit. Across experiments, we varied the duration of the distractors, their motion direction, and task-relevance. We found that abrupt-onset distractors decreased the gain of horizontally directed smooth-pursuit eye-movements. This effect, however, was independent of the similarity in luminance between distractor and target. In addition, distracting effects on horizontal gain were the same, regardless of the exact duration and position of the distractors, suggesting that capture was relatively unspecific and short-lived (Experiments 1 and 2). This was different with distractors moving in a vertical direction, perpendicular to the horizontally moving target. In line with past findings, these distractors caused suppression of vertical gain (Experiment 3). Finally, making distractors task-relevant by asking observers to report distractor positions increased the pursuit gain effect of the distractors. This effect was also independent of target-distractor similarity (Experiment 4). In conclusion, the results suggest that a strong location signal exerted by the pursuit targets led to very brief and largely location-unspecific interference through the abrupt onsets and that this interference was bottom-up, implying that the control of smooth pursuit was independent of other target features besides its motion signal.

Development of a novel tobramycin dependent riboswitch

We herein report the selection and characterization of a new riboswitch dependent on the aminoglycoside tobramycin. Its dynamic range rivals even the tetracycline dependent riboswitch to be the current best performing, synthetic riboswitch that controls translation initiation. The riboswitch was selected with RNA Capture-SELEX, a method that not only selects for binding but also for structural changes in aptamers on binding. This study demonstrates how this method can fundamentally reduce the labour required for the de novo identification of synthetic riboswitches. The initially selected riboswitch candidate harbours two distinct tobramycin binding sites with KDs of 1.1 nM and 2.4 μM, respectively, and can distinguish between tobramycin and the closely related compounds kanamycin A and B. Using detailed genetic and biochemical analyses and 1H NMR spectroscopy, the proposed secondary structure of the riboswitch was verified and the tobramycin binding sites were characterized. The two binding sites were found to be essentially non-overlapping, allowing for a separate investigation of their contribution to the activity of the riboswitch. We thereby found that only the high-affinity binding site was responsible for regulatory activity, which allowed us to engineer a riboswitch from only this site with a minimal sequence size of 33 nt and outstanding performance.

RNA Capture-SELEX on Streptavidin Magnetic Beads

SELEX has enabled the selection of aptamers, nucleic acids that can bind a defined ligand, in some cases with exceptionally high affinity and specificity. The SELEX protocol has been adapted many times to fit a variety of needs. This protocol describes such an adaptation, namely, RNA-Capture SELEX that we have used to successfully develop small molecule-binding RNA aptamers. Our proposed method specifically selects not only for excellent binding but also for conformational switching. In consequence, we found this SELEX method to be particularly suitable for identifying aptamers for further application in synthetic riboswitch engineering.

Substance use disorder and the baby boomers: Does German outpatient addiction care face a change?

Background

The aging of baby boomers is expected to confront addiction care with new challenges. This study aims to investigate if German addiction care is confronted with a sustained change in its clientele that was initiated by the baby boomers.

Methods

Using data from Berlin outpatient addiction care facilities, we contrasted type of primary substance use disorder and number of comorbid substance use disorders in baby boomers with an older (n = 6524) as well as a younger cohort (n = 15677). To isolate cohort effects, two-level random-intercept regression models were applied in the overlapping age groups of the baby boomer cohort with each other cohort.

Results

Compared to the older cohort, alcohol use disorder lost importance while illicit substances use disorder gained importance in the baby boomers. Baby boomers presented a higher number of comorbid substance use disorders than the older cohort. Comparing baby boomers with the younger cohort, these relationships pointed in the opposite direction.

Conclusions

Outpatient addiction care faces a sustained change to more illicit and comorbid substance use disorders. The addiction care system ought to adapt its services to address the changing needs of its clientele.

Key messages

Baby boomers differed in comparison to the older cohort regarding type of substance use disorder and comorbid substance use disorders. The changes set off by the baby boomers continued in the younger cohort.

Reduction of medium consumption in perfusion mammalian cell cultures using a perfusion rate equivalent concentrated nutrient feed

Media preparation for perfusion cell culture processes contributes significantly to operational costs and the footprint of continuous operations for therapeutic protein manufacturing. In this study, definitions are given for the use of a perfusion equivalent nutrient feed stream which, when used in combination with basal perfusion medium, supplements the culture with targeted compounds and increases the medium depth. Definitions to compare medium and feed depth are given in this article. Using a concentrated nutrient feed, a 1.8-fold medium consumption (MC) decrease and a 1.67-fold increase in volumetric productivity (PR) were achieved compared to the initial condition. Later, this strategy was used to push cell densities above 100 × 10⁶ cells/ml while using a perfusion rate below 2 RV/day. In this example, MC was also decreased 1.8-fold compared to the initial condition, but due to the higher cell density, PR was increased 3.1-fold and to an average PR value of 1.36 g L^-1  day^-1 during a short stable phase, and versus 0.46 g L^-1  day^-1 in the initial condition. Overall, the performance improvements were aligned with the given definitions. This multiple feeding strategy can be applied to gain some flexibility during process development and also in a manufacturing set-up to enable better control on nutrient addition.

A light-responsive RNA aptamer for an azobenzene derivative

Regulation of complex biological networks has proven to be a key bottleneck in synthetic biology. Interactions between the structurally flexible RNA and various other molecules in the form of riboswitches have shown a high-regulation specificity and efficiency and synthetic riboswitches have filled the toolbox of devices in many synthetic biology applications. Here we report the development of a novel, small molecule binding RNA aptamer, whose binding is dependent on light-induced change of conformation of its small molecule ligand. As ligand we chose an azobenzene because of its reliable photoswitchability and modified it with chloramphenicol for a better interaction with RNA. The synthesis of the ligand 'azoCm' was followed by extensive biophysical analysis regarding its stability and photoswitchability. RNA aptamers were identified after several cycles of in vitro selection and then studied regarding their binding specificity and affinity toward the ligand. We show the successful development of an RNA aptamer that selectively binds to only the trans photoisomer of azoCm with a KD of 545 nM. As the aptamer cannot bind to the irradiated ligand (λ = 365 nm), a light-selective RNA binding system is provided. Further studies may now result in the engineering of a reliable, light-responsible riboswitch.

Exploring socio-economic inequalities in the use of medicines: is the relation mediated by health status?

OBJECTIVES

This study evaluated mediating effects of the health status on the association between socio-economic status (SES) and medicine use. It was hypothesized that more privileged people show a reduced use of medicines, as compared with the underprivileged, because of their superior health status. It was further hypothesized that people may apply medication based on their type of health complaint (ill physical versus mental status).

STUDY DESIGN

Data were taken from the 2012 German Epidemiological Survey of Substance Abuse, a nationally representative cross-sectional study of n = 9084 individuals of the German general population aged 18-64 years.

METHODS

Direct and indirect effects of SES on weekly use of analgesics and sedatives/hypnotics were examined by applying generalized structural equation modeling. Self-rated physical and mental health statuses were considered as potential mediators. SES was measured by using educational level as a proxy. All analyses were gender-stratified.

RESULTS

Among men, both physical and mental health mediated the path from SES to the use of analgesics and sedatives/hypnotics, respectively, with a stronger effect of physical health on analgesic use and mental health on sedative/hypnotic use. These effects were only partially found among women.

CONCLUSIONS

Social inequalities in health seem to have substantial impact on the prevalence of medicine use. Identification and elimination of the reasons for poor health among people of low SES may, therefore, not only help to reduce health inequalities directly. A decline in the use of medicines would also result in less side-effects and a reduced number of people with medicine-related misuse and addiction.

Early predictive biomarkers for postpartum depression point to a role for estrogen receptor signaling

BACKGROUND

Postpartum depression (PPD) affects approximately 13% of women and has a negative impact on mother and infant, hence reliable biological tests for early detection of PPD are essential. We aimed to identify robust predictive biomarkers for PPD using peripheral blood gene expression profiles in a hypothesis-free genome-wide study in a high-risk, longitudinal cohort.

METHOD

We performed a genome-wide association study in a longitudinal discovery cohort comprising 62 women with psychopathology. Gene expression and hormones were measured in the first and third pregnancy trimesters and early postpartum (201 samples). The replication cohort comprised 24 women with third pregnancy trimester gene expression measures. Gene expression was measured on Illumina-Human HT12 v4 microarrays. Plasma estradiol and estriol were measured. Statistical analysis was performed in R.

RESULTS

We identified 116 transcripts differentially expressed between the PPD and euthymic women during the third trimester that allowed prediction of PPD with an accuracy of 88% in both discovery and replication cohorts. Within these transcripts, significant enrichment of transcripts implicated that estrogen signaling was observed and such enrichment was also evident when analysing published gene expression data predicting PPD from a non-risk cohort. While plasma estrogen levels were not different across groups, women with PPD displayed an increased sensitivity to estrogen signaling, confirming the previously proposed hypothesis of increased sex-steroid sensitivity as a susceptibility factor for PPD.

CONCLUSIONS

These results suggest that PPD can be robustly predicted in currently euthymic women as early as the third trimester and these findings have implications for predictive testing of high-risk women and prevention and treatment for PPD.

Forward scatter target strength extraction in a marine environment (L)

A 48 m rail with a moving receiver was used to measure forward scattering from a spherical shell lying on the bottom in the Gulf of Mexico. The target was mid-way between the source and rail, on a line from the source bisecting the rail. The major obstacle to the measurement of forward scattering is the much stronger source signal which overlaps the scattered signal in space and time. Here, forward scattered target strength is obtained by processing the received signals using a wavenumber filter to remove the incident wave. The result compares favorably to that obtained from numerical predictions.

Structural-acoustic modeling for three-dimensional freefield and littoral environments with verification and validation

This paper describes a high-order, finite-element-based, three-dimensional time-harmonic model for large-scale exterior structural-acoustics problems. It is applicable to both freefield and littoral environments. For the freefield case, the infinite exterior is treated as a homogeneous linear acoustic medium. For littoral applications, the water or air and the sediment domains are each treated as linear homogeneous, semi-infinite half-spaces with piecewise-constant properties. Both domains admit complex-valued wave speeds to enable the inclusion of damping. The finite element formulation uses a variational statement which naturally incorporates the transmission-condition at the water or air-sediment interface. The truncation of the infinite exterior is realized using an infinite-element for the freefield case, and the perfectly-matched-layer approximation for littoral applications. Computation of the farfield quantities is done based on an integral representation which, for the littoral cases, uses efficient approximations for the appropriate Green's function. Numerical computations are presented for a series of progressively more complex problems, and are used to verify the model against analytic and other numerical solutions and validate it based on the experimental data for scattering from elastic scatterers as measured in freefield and sediment pool laboratory facilities.

Role of immunofluorescence microscopy in dermatology

This paper gives a survey about most of the dermatological and infectious cutaneous diseases in which immunofluorescence (IF) microscopy is an important, often decisive tool to reach diagnosis. In tabular form, bullous autoimmune disorders such as pemphigus and pemphigoid diseases, connective tissue diseases, vasculitides, mechanobullous disorders and cutaneous infectious agents and the respective IF findings are listed. Different IF methods and especially important aspects such as taking a biopsy at the right spot or how to send samples are described. Clinical pictures of a broad spectrum of cutaneous diseases are set in combination with the IF microscopic results and the value of special but still routine investigations such as the salt split skin test (SSST) or the antigen mapping (AM) method is demonstrated especially in a set of identical or atypical clinical pictures. Immunofluorescence microscopy has not lost it´s value and should be performed in each dermatological centre in the sense of "Do not miss a diagnosis by not performing IF!"

Exploiting forward scattering for detecting submerged proud/half-buried unexploded ordnance

Laboratory underwater bistatic scattering measurements are reported for free, proud, and half-buried unexploded ordnances for 0 degrees and 90 degrees source angles. Forward echoes are larger than backscattered returns, and half burial significantly decreases the latter but not the former. Results agree with analytic predictions borrowed from radar. The forward echo and source signal are separated by measurements made with and without the target, a method not possible in a target search. For this, a method is described that uses knowledge of the source location and the hyperbolic character in time-cross range of the signals received at points along a line.

Bistatic scattering from submerged unexploded ordnance lying on a sediment

The broadband bistatic target strengths (TSs) of two submerged unexploded ordnance (UXO) targets have been measured in the NRL sediment pool facility. The targets-a 5 in. rocket and a 155 mm projectile-were among the targets whose monostatic TSs were measured and reported previously by the authors. Bistatic TS measurements were made for 0 degrees (target front) and 90 degrees (target side) incident source directions, and include both backscattered and forward scattered echo angles over a complete 360 degrees with the targets placed proud of the sediment surface. For the two source angles used, each target exhibits two strong highlights: a backscattered specular-like echo and a forward scattered response. The TS levels of the former are shown to agree reasonably well with predictions, based on scattering from rigid disks and cylinders, while the levels of the latter with predictions from radar cross section models, based on simple geometric optics appropriately modified. The bistatic TS levels observed for the proud case provide comparable or higher levels of broadband TS relative to free-field monostatic measurements. It is concluded that access to bistatic echo information in operations aimed at detecting submerged UXO targets could provide an important capability.

[Acute alcohol intoxication in adolescents: preliminary results of a pilot project in Munich]

OBJECTIVE

To present preliminary results of a pilot project on the prevention of alcohol-associated problems in adolescents with acute alcohol intoxication.

METHOD

Questionnaires were filled in by 110 of 128 adolescents (85.9% response rate) who had been admitted to a hospital in Munich, Germany, between December 2007 and July 2008, because of alcohol intoxication. Data were obtained on sociodemographic characteristics, alcohol intoxication and drinking patterns, and were analysed using descriptive methods.

RESULTS

Half of these adolescents mainly suffered from moderate to severe degrees of alcohol intoxication. Drinking patterns leading to alcohol intoxication were characterized by relatively low drinking frequency interspersed by episodes of excessive alcohol intake (binge drinking). Thirteen (14.8%) of the adolescents reported previous hospital admissions for alcohol intoxication, nine (17.3%) did not know about the life-threatening danger of alcohol intoxication and twelve (22.2%) reported taking illegal drugs within the last 12 months.

CONCLUSION

Adolescents who had been admitted to hospital because of alcohol intoxication had a drinking pattern which put them at a higher risk for alcohol intoxication and acute alcohol-related problems than adolescents in the general population. Re-admission to hospital within 12 months because of alcohol intoxication, revealing a lack of knowledge about the life-threatening danger of alcohol intoxications and of consuming illegal drugs, may indicate an increased risk for alcohol-related problems. This points to the need for preventive action in adolescents showing these indicators, a need that was met within this pilot project by brief intervention.

Broadband acoustic scattering measurements of underwater unexploded ordnance (UXO)

In order to evaluate the potential for detection and identification of underwater unexploded ordnance (UXO) by exploiting their structural acoustic response, we carried out broadband monostatic scattering measurements over a full 360 degrees on UXO's (two mortar rounds, an artillery shell, and a rocket warhead) and false targets (a cinder block and a large rock). The measurement band, 1-140 kHz, includes a low frequency structural acoustics region in which the wavelengths are comparable to or larger than the target characteristic dimensions. In general, there are aspects that provide relatively high target strength levels ( approximately -10 to -15 dB), and from our experience the targets should be detectable in this structural acoustics band in most acoustic environments. The rigid body scattering was also calculated for one UXO in order to highlight the measured scattering features involving elastic responses. The broadband scattering data should be able to support feature-based separation of UXO versus false targets and identification of various classes of UXO as well.

Cesium uptake from aqueous solutions by bentonite: a comparison of multicomponent sorption with ion-exchange models

The removal of cesium from concentrated aqueous solutions into Ca/Mg-bentonite for a wide range of bentonite-to-water (m/V) ratios was studied experimentally and theoretically. Using the batch technique, the equilibrium of Cs uptake was measured. The nonlinear character of cesium sorption substantially influenced by the m/V ratio was observed. The experimental data were evaluated using the multicomponent Langmuir isotherm and an ion-exchange model based on the ion-exchange reaction between Cs+ and M2+ (Ca2+/Mg2+) initially sorbed on bentonite. Constants k1,Cs = 0.521 mmol.g-1, k2,Cs = 968 L.mol-1, and k2,M = 592 L.mol-1 were obtained for Cs uptake described by multicomponent Langmuir isotherm. For the ion-exchange model, the thermodynamic equilibrium constant K = 75.5 mL.g-1 with a standard deviation of sK = 17.4 mL.g-1 was determined. Using the t test, the calculated data of multicomponent Langmuir and ion-exchange isotherms were fit to experimental data, and the best agreement was obtained for the ion-exchange model. The results show that Cs uptake by bentonite could be substantially decreased in systems with a high bentonite-to-water (m/V) ratio as a consequence of the presence of desorbed divalent cations in the liquid phase.

[Psychosocial stress preceding drug-related deaths]

This article analyses drug-related deaths in the German Federal States of Bavaria (Munich, Nuremberg and Augsburg counties) during 1999 and Baden-Wurttemberg (Stuttgart and Mannheim counties) during 1999 and in the first half of 2000. The persons who had been in contact with drug care services were studied for psychosocial stress preceding drug-related deaths. Epidemiological data from different sources (police, relatives, counselling centres, detoxification clinics, therapy and substitution treatment) were collated to estimate factors of psychosocial stress preceding drug deaths. The results in both Laender indicate high prevalence rates of a history of at least one non-fatal overdose (approx. 50%) or a suicide attempt (approx. 35%). More than 40% of the deceased had been suffering from at least one additional mental disorder, in most cases from depression. At least one critical life event (in most cases, a relapse) or a period of abstinence (i.e., due to imprisonment, therapy or detoxification) during the past three months before death was reported for more than half of the addicts. The results were discussed in the light of data on opiate users and the general population. Improved specialist training of therapeutic and medical workers as well as of any other co-operating professionals is considered a necessary prerequisite for an early detection of risk factors.

[The influence of regional differences in drinking style on hazardous use, excessive drinking, abuse and dependence]

INTRODUCTION

Previous research in Germany identified a "north-south" gradient in the hazardous use of alcoholic drinks, but this had methodological limitations. The present study estimates the hazardous use of alcohol more reliably. In addition, regional differences in drinking style and their relation to indicators of problematic alcohol use are examined.

METHODS

Data are from 1995 and 1997 representative samples of the non-institutionalised German general population aged 18 to 59 years. Based on 15,017 complete observations prevalence rates for abstinence, hazardous consumption (>30 g ethanol per day for men; >20 g ethanol per day for women), two or more CAGE-symptoms, and heavy episodic drinking (5+ drinks consumed in a day) were calculated and a cluster analysis was performed with regard to the 16 German federal states.

RESULTS

Regional differences exist in the prevalence of abstinence and hazardous drinking, but a "north-south" gradient was not evident. However, cluster analysis results suggest a "north-south" difference in drinking style, i.e. the quantity-frequency pattern of beer, wine, and spirits consumption. Compared with the northern German federal states, those in the south experienced more beer and less wine and spirits consumption in combination with a lower frequency of drinking beer and spirits. No cluster difference was found for hazardous drinking, lifetime prevalence of 2+ CAGE items or consumption of 5+ drinks in a day. Yet, mean consumption of ethanol was significantly higher in the north.

CONCLUSIONS

Research suggesting more hazardous consumption in southern Germany must be tempered by these findings that found no 'north-south' gradient in several different indicators of problematic alcohol use. Different drinking styles in northern and southern states do not result in differences concerning prevalence of binge drinking nor alcohol-related problems. Drinking style only made a difference in the mean consumption of ethanol. Methodological differences between the reported studies are discussed.

A comparison of different methods for estimating the prevalence of problematic drug misuse in Great Britain

AIMS

The European Monitoring Centre for Drugs and Drug Addiction (EMCDDA) has produced methodological guidelines for national drug prevalence estimation. This paper pilots the methods to estimate prevalence for Great Britain and provides a commentary on the methods and resulting estimates.

DESIGN

Three types of methodology were used to estimate prevalence: (a) the multiple indicator (MI) method, (b) multipliers applied to (i) drug-treatment records (ii) HIV estimates and (iii) mortality statistics and (c) the British/Scottish Crime Surveys.

SETTING

England, Scotland and Wales.

PARTICIPANTS

Aggregated data on people recorded on databases and respondents in household surveys.

MEASUREMENTS

Prevalence estimates of different forms of problematic drug use.

FINDINGS

The estimates are 161,133 (range: 120,850-241,700) for people at risk of mortality due to drug overdose; 161,000-169,000 for people who have ever injected drugs; 202,000 (range: 162,000-244,000) problem opiate users and 268,000 problem drug users (all types).

CONCLUSIONS

The multiple indicator method offers a comprehensive approach to estimating the prevalence of problematic drug use in the United Kingdom. Simple multiplier methods and household surveys also provide a range of estimates corresponding to different types of drug use in the United Kingdom. The current study suggests that previous national estimates of 100,000-200,000 were conservative. The new estimate of 161,000-266,000 should enable a more focused response. For further development of this method, reliable and timely estimates of anchor points are required for specific geographical areas such as cities or Drug Action Teams (DAT), as well as routine aggregation of drug indicators for these areas.