Prediction underlying comprehension of human motion: an analysis of Deaf signer and non-signer EEG in response to visual stimuli

Introduction

Sensory inference and top-down predictive processing, reflected in human neural activity, play a critical role in higher-order cognitive processes, such as language comprehension. However, the neurobiological bases of predictive processing in higher-order cognitive processes are not well-understood.

Methods

This study used electroencephalography (EEG) to track participants' cortical dynamics in response to Austrian Sign Language and reversed sign language videos, measuring neural coherence to optical flow in the visual signal. We then used machine learning to assess entropy-based relevance of specific frequencies and regions of interest to brain state classification accuracy.

Results

EEG features highly relevant for classification were distributed across language processing-related regions in Deaf signers (frontal cortex and left hemisphere), while in non-signers such features were concentrated in visual and spatial processing regions.

Discussion

The results highlight functional significance of predictive processing time windows for sign language comprehension and biological motion processing, and the role of long-term experience (learning) in minimizing prediction error.

Low-Frequency Entrainment to Visual Motion Underlies Sign Language Comprehension

When people listen to speech, neural activity tracks the entropy fluctuation in the acoustic envelope of the signal. This signal-based entrainment has been shown to be the basis of speech parsing and comprehension. In this electroencephalography (EEG) study, we compute sign language users’ cortical tracking of changes in visual dynamics of the communicative signal in the time-direct videos of sign language, and their time-reversed counterparts, and assess the relative contribution of response frequencies between.2 and 12.4 Hz to comprehension using a machine learning approach to brain state classification. Lower frequencies of EEG response (.2–4 Hz) yield 100% classification accuracy, while information about cortical tracking of the visual envelope in higher frequencies is less informative. This suggests that signers rely on lower visual frequency data, such as envelope of visual signal, for sign language comprehension. In the context of real-time language processing, given the speed of comprehension responses, this suggests that fluent signers employ a predictive processing heuristic based on sign language knowledge.

Age of sign language acquisition has lifelong effect on syntactic preferences in sign language users

Acquisition of natural language has been shown to fundamentally impact both one's ability to use the first language, and the ability to learn subsequent languages later in life. Sign languages offer a unique perspective on this issue, because Deaf signers receive access to signed input at varying ages. The majority acquires sign language in (early) childhood, but some learn sign language later - a situation that is drastically different from that of spoken language acquisition. To investigate the effect of age of sign language acquisition and its potential interplay with age in signers, we examined grammatical acceptability ratings and reaction time measures in a group of Deaf signers (age range: 28-58 years) with early (0-3 years) or later (4-7 years) acquisition of sign language in childhood. Behavioral responses to grammatical word order variations (subject-object-verb vs. object-subject-verb) were examined in sentences that included: 1) simple sentences, 2) topicalized sentences, and 3) sentences involving manual classifier constructions, uniquely characteristic of sign languages. Overall, older participants responded more slowly. Age of acquisition had subtle effects on acceptability ratings, whereby the direction of the effect depended on the specific linguistic structure.

Classification of visual comprehension based on EEG data using sparse optimal scoring

OBJECTIVE

Understanding and differentiating brain states is an important task in the field of cognitive neuroscience with applications in health diagnostics (such as detecting neurotypical development vs. Autism Spectrum or coma/vegetative state vs. locked-in state). Electroencephalography (EEG) analysis is a particularly useful tool for this task as EEG data can detect millisecond-level changes in brain activity across a range of frequencies in a non-invasive and relatively inexpensive fashion. The goal of this study is to apply machine learning methods to EEG data in order to classify visual language comprehension across multiple participants.

APPROACH

26-channel EEG was recorded for 24 Deaf participants while they watched videos of sign language sentences played in time-direct and time-reverse formats to simulate interpretable vs. uninterpretable sign language, respectively. Sparse Optimal Scoring (SOS) was applied to EEG data in order to classify which type of video a participant was watching, time-direct or time-reversed. The use of SOS also served to reduce the dimensionality of the features to improve model interpretability.

MAIN RESULTS

The analysis of frequency-domain EEG data resulted in an average out-of-sample classification accuracy of 98.89%, which was far superior to the time-domain analysis. This high classification accuracy suggests this model can accurately identify common neural responses to visual linguistic stimuli.

SIGNIFICANCE

The significance of this work is in determining necessary and sufficient neural features for classifying the high-level neural process of visual language comprehension across multiple participants.

Psycholinguistic mechanisms of classifier processing in sign language

Nonsigners viewing sign language are sometimes able to guess the meaning of signs by relying on the overt connection between form and meaning, or iconicity (cf. Ortega, Özyürek, & Peeters, 2020; Strickland et al., 2015). One word class in sign languages that appears to be highly iconic is classifiers: verb-like signs that can refer to location change or handling. Classifier use and meaning are governed by linguistic rules, yet in comparison with lexical verb signs, classifiers are highly variable in their morpho-phonology (variety of potential handshapes and motion direction within the sign). These open-class linguistic items in sign languages prompt a question about the mechanisms of their processing: Are they part of a gestural-semiotic system (processed like the gestures of nonsigners), or are they processed as linguistic verbs? To examine the psychological mechanisms of classifier comprehension, we recorded the electroencephalogram (EEG) activity of signers who watched videos of signed sentences with classifiers. We manipulated the sentence word order of the stimuli (subject-object-verb [SOV] vs. object-subject-verb [OSV]), contrasting the two conditions, which, according to different processing hypotheses, should incur increased processing costs for OSV orders. As previously reported for lexical signs, we observed an N400 effect for OSV compared with SOV, reflecting increased cognitive load for linguistic processing. These findings support the hypothesis that classifiers are a linguistic part of speech in sign language, extending the current understanding of processing mechanisms at the interface of linguistic form and meaning. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Psychosis in German prisoners: Comparison of the clinical appearance of psychotic disorder of an imprisoned population with a not detained community group

Surveys confirm risk factors for the incarceration of patients with psychosis including homelessness and comorbidity. There is also agreement that severe psychosis can lead to violence. Data describing prisoners with psychosis in Germany are scarce. We aimed to compare patients with psychosis in a prison hospital and patients with psychosis in a community hospital. Demographic data were collected, as well as comorbidity in the form of substance dependence and a psychiatric assessment using the German version of the 18-item Brief Psychiatric Rating Scale (BPRS) and the Positive and Negative Syndrome Scale (PANSS). In the prison hospital group more patients were homeless (17 versus 2%) and non-German (36 versus 4%). There were also more patients with substance dependence or abuse in the prison hospital group. The total scores of BPRS and PANSS were lower in the prison hospital group (BPRS, 43.8 versus 51.2; PANSS, 71.5 versus 83.7). We assume that social disintegration for mentally disturbed offenders prior to incarceration hindered effective treatment. To avoid further social disintegration and possible further deterioration of mental health status of released offenders, which may lead to reoffending after imprisonment, discharge management after release from prison should be improved.

Applicability of two violence risk assessment tools in a psychiatric prison hospital population

The risk of violent behavior is known to be higher for patients who suffer from a severe mental disorder. However, specific prediction tools for clinical work in prison psychiatry are lacking. In this single-center study, two violence risk assessment tools (Forensic Psychiatry and Violence Tool, "FoVOx," and Mental Illness and Violence Tool, "OxMIV") were applied to a prison hospital population with a primary psychotic or bipolar disorder and subsequently compared. The required information on all items of both tools was obtained retrospectively for a total of 339 patients by evaluation of available patient files. We obtained the median and inter-quartile range for both FoVOx and OxMIV, and their rank correlation coefficient along with 95% confidence intervals (CIs)-for the full cohort, as well as for cohort subgroups. The two risk assessment tools were strongly positively correlated (Spearman correlation = 0.83; 95% CI = 0.80-0.86). Such a high correlation was independent of nationality, country of origin, type of detention, schizophrenia-spectrum disorder, previous violent crime and alcohol use disorder, where correlations were above 0.8. A lower correlation was seen with patients who were 30 years old or more, married, with affective disorder and with self-harm behavior, and also in patients without aggressive behavior and without drug use disorder. Both risk assessment tools are applicable as an adjunct to clinical decision making in prison psychiatry.

Age of acquisition effects differ across linguistic domains in sign language: EEG evidence

One of the key questions in the study of human language acquisition is the extent to which the development of neural processing networks for different components of language are modulated by exposure to linguistic stimuli. Sign languages offer a unique perspective on this issue, because prelingually Deaf children who receive access to complex linguistic input later in life provide a window into brain maturation in the absence of language, and subsequent neuroplasticity of neurolinguistic networks during late language learning. While the duration of sensitive periods of acquisition of linguistic subsystems (sound, vocabulary, and syntactic structure) is well established on the basis of L2 acquisition in spoken language, for sign languages, the relative timelines for development of neural processing networks for linguistic sub-domains are unknown. We examined neural responses of a group of Deaf signers who received access to signed input at varying ages to three linguistic phenomena at the levels of classifier signs, syntactic structure, and information structure. The amplitude of the N400 response to the marked word order condition negatively correlated with the age of acquisition for syntax and information structure, indicating increased cognitive load in these conditions. Additionally, the combination of behavioral and neural data suggested that late learners preferentially relied on classifiers over word order for meaning extraction. This suggests that late acquisition of sign language significantly increases cognitive load during analysis of syntax and information structure, but not word-level meaning.

Prevalence of Opioid Dependence and Opioid Agonist Treatment in the Berlin Custodial Setting: A Cross-Sectional Study

BACKGROUND

Among people living in detention, substance use is highly prevalent, including opioid dependence. Opioid agonist treatment (OAT) has been established as an evidence-based, first-line treatment for opioid dependence. Despite high prevalence of opioid dependence, conclusive data regarding its prevalence and the OAT practice in German prisons is scarce; rather, the existing data widely diverges concerning the rates of people in detention receiving OAT.

MATERIALS AND METHODS

We conducted a cross-sectional survey of all detention facilities in Berlin. On the date of data collection, a full census of the routine records was completed based on the medical documentation system. For each opioid dependent individual, we extracted sociodemographic data (i.e., age, sex, and non-/German nationality, whether people experienced language-related communication barriers), information about OAT, comorbidities (HIV, hepatitis C, schizophrenia), and the detention center, as well as the anticipated imprisonment duration and sentence type. The data was first analyzed descriptively and secondly in an evaluative-analytical manner by analyzing factors that influence the access to OAT of people living in detention.

RESULTS

Among the 4,038 people in detention in the Berlin custodial setting under investigation, we identified a 16% prevalence of opioid dependence. Of the opioid-dependent individuals, 42% received OAT; 31% were treated with methadone, 55% were treated with levomethadone, and 14% were treated with buprenorphine. Access to OAT seemed mainly dependent upon initial receipt of OAT at the time of imprisonment, detention duration, the prisons in which individuals were detained, German nationality, and sex. The overall prevalence of HIV was 4-8%, hepatitis C was 31-42%, and schizophrenia was 5%.

CONCLUSIONS

The prevalence of opioid dependence and access to OAT remains a major health issue in the custodial setting. OAT implementation must be especially intensified among male, non-German, opioid-dependent individuals with a short detention period. Treatment itself must be diversified regarding the substances used for OAT, and institutional treatment differences suggest the need for a consistent treatment approach and the standardized implementation of treatment guidelines within local prison's standard operating procedures. Testing for infectious diseases should be intensified among opioid-dependent people living in detention to address scarcely known infection statuses and high infection rates.

The Impact of Transitional Movements and Non-Manual Markings on the Disambiguation of Locally Ambiguous Argument Structures in Austrian Sign Language (ÖGS)

Previous studies of Austrian Sign Language (ÖGS) word-order variations have demonstrated the human processing system's tendency to interpret a sentence-initial (case-) ambiguous argument as the subject of the clause ("subject preference"). The electroencephalogram study motivating the current report revealed earlier reanalysis effects for object-subject compared to subject-object sentences, in particular, before the start of the movement of the agreement marking sign. The effects were bound to time points prior to when both arguments were referenced in space and/or the transitional hand movement prior to producing the disambiguating sign. Due to the temporal proximity of these time points, it was not clear which visual cues led to disambiguation; that is, whether non-manual markings (body/shoulder/head shift towards the subject position) or the transitional hand movement resolved ambiguity. The present gating study further supports that disambiguation in ÖGS is triggered by cues occurring before the movement of the disambiguating sign. Further, the present study also confirms the presence of the subject preference in ÖGS, showing again that signers and speakers draw on similar strategies during language processing independent of language modality. Although the ultimate role of the visual cues leading to disambiguation (i.e., non-manual markings and transitional movements) requires further investigation, the present study shows that they contribute crucial information about argument structure during online processing. This finding provides strong support for granting these cues some degree of linguistic status (at least in ÖGS).

Global distribution of earthworm diversity

Soil organisms, including earthworms, are a key component of terrestrial ecosystems. However, little is known about their diversity, their distribution, and the threats affecting them. We compiled a global dataset of sampled earthworm communities from 6928 sites in 57 countries as a basis for predicting patterns in earthworm diversity, abundance, and biomass. We found that local species richness and abundance typically peaked at higher latitudes, displaying patterns opposite to those observed in aboveground organisms. However, high species dissimilarity across tropical locations may cause diversity across the entirety of the tropics to be higher than elsewhere. Climate variables were found to be more important in shaping earthworm communities than soil properties or habitat cover. These findings suggest that climate change may have serious implications for earthworm communities and for the functions they provide.

High-Definition Zoom Mode, a High-Resolution X-Ray Microscope for Neurointerventional Treatment Procedures: A Blinded-Rater Clinical-Utility Study

BACKGROUND AND PURPOSE

Quality of visualization of treatment devices during critical stages of endovascular interventions, can directly impact their safety and efficacy. Our aim was to compare the visualization of neurointerventional procedures and treatment devices using a 194-μm pixel flat panel detector mode and a 76-μm pixel complementary metal oxide semiconductor detector mode (high definition) of a new-generation x-ray detector system using a blinded-rater study.

MATERIALS AND METHODS

Deployment of flow-diversion devices for the treatment of internal carotid artery aneurysms was performed under flat panel detector and high-definition-mode image guidance in a neurointerventional phantom simulating patient cranium and tissue attenuation, embedded with 3D-printed intracranial vascular models, each with an aneurysm in the ICA segment. Image-sequence pairs of device deployments for each detector mode, under similar exposure and FOV conditions, were evaluated by 2 blinded experienced neurointerventionalists who independently selected their preferred image on the basis of visualization of anatomic features, image noise, and treatment device. They rated their selection as either similar, better, much better, or substantially better than the other choice. Inter- and intrarater agreement was calculated and categorized as poor, moderate, and good.

RESULTS

Both raters demonstrating good inter- and intrarater agreement selected high-definition-mode images with a frequency of at least 95% each and, on average, rated the high-definition images as much better than flat panel detector images with a frequency of 73% from a total of 60 image pairs.

CONCLUSIONS

Due to their higher resolution, high-definition-mode images are sharper and visually preferred compared with the flat panel detector images. The improved imaging provided by the high-definition mode can potentially provide an advantage during neurointerventional procedures.

A Type 1 Diabetes Genetic Risk Score Predicts Progression of Islet Autoimmunity and Development of Type 1 Diabetes in Individuals at Risk

OBJECTIVE

We tested the ability of a type 1 diabetes (T1D) genetic risk score (GRS) to predict progression of islet autoimmunity and T1D in at-risk individuals.

RESEARCH DESIGN AND METHODS

We studied the 1,244 TrialNet Pathway to Prevention study participants (T1D patients' relatives without diabetes and with one or more positive autoantibodies) who were genotyped with Illumina ImmunoChip (median [range] age at initial autoantibody determination 11.1 years [1.2-51.8], 48% male, 80.5% non-Hispanic white, median follow-up 5.4 years). Of 291 participants with a single positive autoantibody at screening, 157 converted to multiple autoantibody positivity and 55 developed diabetes. Of 953 participants with multiple positive autoantibodies at screening, 419 developed diabetes. We calculated the T1D GRS from 30 T1D-associated single nucleotide polymorphisms. We used multivariable Cox regression models, time-dependent receiver operating characteristic curves, and area under the curve (AUC) measures to evaluate prognostic utility of T1D GRS, age, sex, Diabetes Prevention Trial-Type 1 (DPT-1) Risk Score, positive autoantibody number or type, HLA DR3/DR4-DQ8 status, and race/ethnicity. We used recursive partitioning analyses to identify cut points in continuous variables.

RESULTS

Higher T1D GRS significantly increased the rate of progression to T1D adjusting for DPT-1 Risk Score, age, number of positive autoantibodies, sex, and ethnicity (hazard ratio [HR] 1.29 for a 0.05 increase, 95% CI 1.06-1.6; P = 0.011). Progression to T1D was best predicted by a combined model with GRS, number of positive autoantibodies, DPT-1 Risk Score, and age (7-year time-integrated AUC = 0.79, 5-year AUC = 0.73). Higher GRS was significantly associated with increased progression rate from single to multiple positive autoantibodies after adjusting for age, autoantibody type, ethnicity, and sex (HR 2.27 for GRS >0.295, 95% CI 1.47-3.51; P = 0.0002).

CONCLUSIONS

The T1D GRS independently predicts progression to T1D and improves prediction along T1D stages in autoantibody-positive relatives.

Initial investigations of a special high-definition (Hi-Def) zoom capability in a new detector system for neuro-interventional procedures

Real-time visualization of fine details ranging to 100 um or less in neuro-vascular imaging guided interventions is important. A separate high-resolution detector mounted on a standard flat panel detector (FPD) was previously reported. This device had to be rotated mechanically into position over the FPD for high resolution imaging. Now, the new detector reported here has a high definition (Hi-Def) zoom capability along with the FPD built into one unified housing. The new detector enables rapid switching, by the operator between Hi-Def and FPD modes. Standard physical metrics comparing the new Hi-Def modes with those of the FPD are reported, demonstrating improved imaging resolution and noise capability at patient doses similar to those used for the FPD. Semi-quantitative subjective studies involving qualitative clinician feedback on images of interventional devices such as a Pipeline Embolization Device (PED) acquired in both Hi-Def and FPD modes are presented. The PED is deployed in a patient specific 3D printed neuro-vascular phantom embedded inside realistic bone and with tissue attenuating material. Field-of-view (FOV), exposure and magnification were kept constant for FPD and Hi-Def modes. Static image comparisons of the same view of the PED within the phantom were rated by expert interventionalists who chose from the following ratings: Similar, Better, or Superior. Generally, the Hi-Def zoomed images were much preferred over the FPD, indicating the potential to improve endovascular procedures and hence outcomes using such a Hi-Def feature.

Spectroscopy with a CdTe-based photon-counting imaging detector (PCD) having charge sharing correction capability

The spectroscopic capabilities of a newly upgraded version of a prototype imaging photon counting detector (PCD) was investigated. The XCounter Actaeon has four acquisition modes in which signal processing is varied including one mode having a charge sharing correction so that neighboring pixels that share a detected event will not be erroneously counted twice, hence it is designated the Anti-Coincidence Circuit On or ACC On mode. Since this CdTe-based direct conversion PCD has 100 μm pixels, such charge sharing may frequently occur for typical medical x-ray energies. Each pixel of this PCD has two scalers and two energy discriminators that enable counting without instrumentation noise of events above each threshold level; hence, a spectrum can be obtained by sequentially moving the thresholds of both discriminators. It became evident from the spectra for the various acquisition modes that only those obtained with the charge sharing correction enabled, compared favorably with theoretically predicted spectra. After verifying the energy calibration using the mono-energetic emissions from an Am-241 source, spectra at various kVps from a standard medical x-ray generator were obtained. The spectra generated by ACC On mode for 70 kVp and 110 kVp were the closest match to the theoretical spectra generated by SpekCal. For dual energy applications, ACC On mode with charge sharing correction circuitry would be the best choice among various acquisition modes. Also investigated was the dual energy imaging capability of the Actaeon PCD with ACC On mode to separate Aluminum and Iodine while imaging an artery stenosis phantom.

Gantry rotational motion-induced blur in cone-beam computed tomography

As neuro-endovascular image-guided interventions (EIGIs) make use of higher resolution detectors, gantry rotational motion-induced blur becomes more noticeable in acquired projections as well as reconstructed images by reducing the visibility of vascular and device features whose visualization could be critical in the treatment of vascular pathology. Motion-induced blur in projections views is a function of an object's position in the field-of-view (FOV), gantry rotational speed, and frame capture or exposure time. In this work different frame rates were used to investigate the effects of blurring from individual projections on the reconstructed image. To test the effects of these parameters on reconstructed images, a regular pattern phantom of small objects was simulated and projection views were generated at various different frame rates for a given simulated rotational velocity. The reconstruction was made using a linear interpolation of filtered backprojections. Images reconstructed from lower frame rates showed significant blurring in the azimuthal direction, increasingly worse towards the periphery of the image. However, those reconstructed from higher frame rates showed significantly less blur throughout the entire FOV. While lower frame rates could be used with slower gantry speeds this would increase the risk of voluntary or involuntary patient motion contributing to blur over the entire FOV. A high frame rate used with high gantry speeds could reliable provide images without gantry-motion blur while reducing the risk of patient-motion blur. Frame rates exceeding 2000 fps available with photon counting detectors such as the X-counter Actaeon¹ are available.

Evaluation of a new photon-counting imaging detector (PCD) with various acquisition modes

The prospect of improved low noise, high speed, and dual-energy imaging that may be associated with the use of photon-counting imaging detectors (PCD) has motivated this evaluation of a newly upgraded version of a prototype PCD. The XCounter Actaeon was evaluated in its four acquisition modes each based upon varying signal processing firmware including a mode with charge sharing correction that enables neighboring pixels that share the energy from one incident x-ray photon detection to be counted only once at the proper summed energy in the pixel with the largest charge deposition. Since this PCD is a CdTe-based direct detector with 100 μm pixels, such charge sharing for typical medical x-ray energy photons may occur frequently and must be corrected to achieve more accurate counts. This charge sharing correction is achieved with an Anti-Coincidence Circuit (ACC) which prevents double pixel counting from one event as well as prevents counting from either event if they are below a preset threshold. Various physical parameters of the PCD were evaluated including linearity, sensitivity, pulse pile-up effects, dark noise, spatial resolution, noise power spectrum, and detective quantum efficiency.

The effects of antimuscarinic treatment on the cognition of spinal cord injured individuals with neurogenic lower urinary tract dysfunction: a prospective controlled before-and-after study

STUDY DESIGN

Prospective controlled before-and-after study.

OBJECTIVES

To investigate the effects of antimuscarinic treatment of neurogenic lower urinary tract dysfunction on the cognition of individuals with spinal cord injury (SCI) during the early post-acute phase.

SETTING

Single SCI rehabilitation center.

METHODS

Patients with acute traumatic SCI admitted for primary rehabilitation from 2011 to 2015 were screened for study enrollment. Study participants underwent baseline neuropsychological assessments prior to their first urodynamic evaluation (6-8 weeks after SCI). Individuals suffering from neurogenic detrusor overactivity received antimuscarinic treatment, and those not requiring antimuscarinic treatment constituted the control group. The neuropsychological follow-up assessment was carried out 3 months after the baseline assessment. The effects of group and time on the neuropsychological parameters were investigated.

RESULTS

The data of 29 individuals were evaluated (control group 19, antimuscarinic group 10). The group had a significant (P≤0.033) effect on immediate recall, attention ability and perseveration. In the control group, individuals performed significantly (P≤0.05) better in immediate recall both at baseline (percentile rank 40, 95% CI 21-86 versus 17, 95% CI 4-74) and follow-up (percentile rank 40, 95% CI 27-74 versus 16, 95% CI 2-74). The time had a significant (P≤0.04) effect on attention ability, processing speed, word fluency and visuospatial performance. The individuals in both groups performed better at the follow-up compared to the baseline assessment.

CONCLUSION

Even though, we did not observe cognitive deterioration in the investigated, cognitively intact SCI individuals during the first 3 treatment months, the concerns regarding deleterious effects of antimuscarinics on cognition remain.

Cast aluminium single crystals cross the threshold from bulk to size-dependent stochastic plasticity

Metals are known to exhibit mechanical behaviour at the nanoscale different to bulk samples. This transition typically initiates at the micrometre scale, yet existing techniques to produce micrometre-sized samples often introduce artefacts that can influence deformation mechanisms. Here, we demonstrate the casting of micrometre-scale aluminium single-crystal wires by infiltration of a salt mould. Samples have millimetre lengths, smooth surfaces, a range of crystallographic orientations, and a diameter D as small as 6 μm. The wires deform in bursts, at a stress that increases with decreasing D. Bursts greater than 200 nm account for roughly 50% of wire deformation and have exponentially distributed intensities. Dislocation dynamics simulations show that single-arm sources that produce large displacement bursts halted by stochastic cross-slip and lock formation explain microcast wire behaviour. This microcasting technique may be extended to several other metals or alloys and offers the possibility of exploring mechanical behaviour spanning the micrometre scale.

Tetrahydroanthraquinone Derivative (±)-4-Deoxyaustrocortilutein Induces Cell Cycle Arrest and Apoptosis in Melanoma Cells via Upregulation of p21 and p53 and Downregulation of NF-kappaB

BACKGROUND

Malignant melanoma is an aggressive type of skin cancer with high risk for metastasis and chemoresistance. Disruption of tightly regulated processes such as cell cycle, cell adhesion, cell differentiation and cell death are predominant in melanoma development. So far, conventional treatment options have been insufficient to treat metastatic melanoma and survival rates are poor. Anthraquinone compounds have been reported to have anti-tumorigenic potential by DNA-interaction, promotion of apoptosis and suppression of proliferation in various cancer cells.

METHODS

In the current study, the racemic tetrahydroanthraquinone derivative (±)-4-deoxyaustrocortilutein (4-DACL) was synthesized and the cytotoxic activity against melanoma cells and melanoma spheroids determined by CellTiter-Blue viability Assay and phase contrast microscopy. Generation of reactive oxygen species (ROS) was determined with CellROX Green and Deep Red Reagent kit and microplate-based fluorometry. Luciferase reporter gene assays for nuclear factor kappa B (NF-κB) and p53 activities and western blotting analysis were carried out to detect the expression of anti-proliferative or pro-apoptotic (p53, p21, p27, MDM2, and GADD45M) and anti-apoptotic (p65, IκB-α, IKK) proteins. Cell cycle distribution and apoptosis rate were detected by flow cytometry, the morphological changes visualized by fluorescence microscopy and the activation of different caspase cascades distinguished by Caspase Glo 3/7, 8 and 9 Assays.

RESULTS

We demonstrated that 4-DACL displayed high activity against different malignant melanoma cells and melanoma spheroids and only low toxicity to melanocytes and other primary cells. In particular, 4-DACL treatment induced mitochondrial ROS, reduced NF-κB signaling activity and increased up-regulation of the cell cycle inhibitors cyclin-dependent kinase inhibitor p21 (p21(WAF1/Cip1)) and the tumor suppressor protein p53 in a dose-dependent manner, which was accompanied by decreased cell proliferation and apoptosis via the intrinsic pathway.

CONCLUSION

According to these results, we suggest that 4-DACL may be a promising therapeutic agent for the treatment of malignant melanoma.

Risk factors for symptomatic urinary tract infections in individuals with chronic neurogenic lower urinary tract dysfunction

STUDY DESIGN

Retrospective investigation.

OBJECTIVES

To investigate the association of patient and injury characteristics, as well as bladder management, with the occurrence of patient-reported, symptomatic urinary tract infection(s) UTI(s) in patients with chronic neurogenic lower urinary tract dysfunction (NLUTD).

SETTING

Tertiary urologic referral center.

METHODS

The patient database was screened for patients with chronic (>12 months) NLUTD who had presented between 2008 and 2012. Patient characteristics, bladder evacuation management, the annual number of patient-reported, symptomatic UTIs and the type of prophylactic treatment to prevent UTIs were collected. Binary logistic regression analysis was used to investigate the effects of the investigated risk factors on the occurrence of symptomatic UTI(s) and recurrent symptomatic UTIs (⩾3 annual UTIs).

RESULTS

The data of 1104 patients with a mean NLTUD duration of 20.3±11.6 years were investigated. The evacuation method was a significant (P⩽0.004) predictor for the occurrence of symptomatic UTI and recurrent symptomatic UTIs. The greatest annual number of symptomatic UTIs was observed in patients using transurethral indwelling catheters, and the odds of experiencing a UTI and recurrent UTIs were increased more than 10- and 4-fold, respectively. The odds of a UTI or recurrent UTIs were also increased significantly (P⩽0.014) in patients using intermittent catheterization (IC). Botulinum toxin injections into the detrusor increased the odds of a UTI ~10-fold (P=0.03).

CONCLUSIONS

The bladder evacuation method is the main predictor for symptomatic UTIs in individuals with NLUTD. Transurethral catheters showed the highest odds of symptomatic UTI and should be avoided whenever possible.

Fighting Sleep at Night: Brain Correlates and Vulnerability to Sleep Loss

OBJECTIVE

Even though wakefulness at night leads to profound performance deterioration and is regularly experienced by shift workers, its cerebral correlates remain virtually unexplored.

METHODS

We assessed brain activity in young healthy adults during a vigilant attention task under high and low sleep pressure during night-time, coinciding with strongest circadian sleep drive. We examined sleep-loss-related attentional vulnerability by considering a PERIOD3 polymorphism presumably impacting on sleep homeostasis.

RESULTS

Our results link higher sleep-loss-related attentional vulnerability to cortical and subcortical deactivation patterns during slow reaction times (i.e., suboptimal vigilant attention). Concomitantly, thalamic regions were progressively less recruited with time-on-task and functionally less connected to task-related and arousal-promoting brain regions in those volunteers showing higher attentional instability in their behavior. The data further suggest that the latter is linked to shifts into a task-inactive default-mode network in between task-relevant stimulus occurrence.

INTERPRETATION

We provide a multifaceted view on cerebral correlates of sleep loss at night and propose that genetic predisposition entails differential cerebral coping mechanisms, potentially compromising adequate performance during night work.

Testicular resistive index determined by Doppler ultrasonography in men with spinal cord injury - a case series

In this case series, the testicular resistive index was determined in men with spinal cord injury. In ten men participating in our fertility programme, the peak systolic and end-diastolic velocity of centripetal testicular arteries was measured in triplicates by Doppler ultrasonography to calculate the testicular resistive index. Furthermore, the right and left testicular volume was determined by ultrasonography, blood samples were obtained for hormonal evaluation, and sperm analysis was performed according to the WHO guidelines. The median testicular resistive index measured 0.69 and was significantly (P < 0.001) greater than the reported cut-off value of 0.6. The spermiograms were characterised by normal sperm count but decreased sperm motility and plasma membrane integrity. The median right and left testicular volume was significantly (P < 0.01) smaller compared to the volumes measured in able-bodied adult males without scrotal pathology and measured 8.4 ml and 7.2 ml respectively. There was a significant (P = 0.005) correlation (rs  = 0.81) between testicular resistive index and sperm concentration. However, no correlations were observed between testicular resistive index and other variables. The testicular resistive index in men with spinal cord injury was significantly greater than 0.6. Measuring the testicular resistive index may represent a useful additional parameter in the assessment of infertility in spinal cord-injured men.

Time-on-task decrement in vigilance is modulated by inter-individual vulnerability to homeostatic sleep pressure manipulation

Under sleep loss, vigilance is reduced and attentional failures emerge progressively. It becomes difficult to maintain stable performance over time, leading to growing performance variability (i.e., state instability) in an individual and among subjects. Task duration plays a major role in the maintenance of stable vigilance levels, such that the longer the task, the more likely state instability will be observed. Vulnerability to sleep-loss-dependent performance decrements is highly individual and is also modulated by a polymorphism in the human clock gene PERIOD3 (PER3). By combining two different protocols, we manipulated sleep-wake history by once extending wakefulness for 40 h (high sleep pressure condition) and once by imposing a short sleep-wake cycle by alternating 160 min of wakefulness and 80 min naps (low sleep pressure condition) in a within-subject design. We observed that homozygous carriers of the long repeat allele of PER3 (PER3 (5/5) ) experienced a greater time-on-task dependent performance decrement (i.e., a steeper increase in the number of lapses) in the Psychomotor Vigilance Task compared to the carriers of the short repeat allele (PER3 (4/4) ). These genotype-dependent effects disappeared under low sleep pressure conditions, and neither motivation, nor perceived effort accounted for these differences. Our data thus suggest that greater sleep-loss related attentional vulnerability based on the PER3 polymorphism is mirrored by a greater state instability under extended wakefulness in the short compared to the long allele carriers. Our results undermine the importance of time-on-task related aspects when investigating inter-individual differences in sleep loss-induced behavioral vulnerability.

Acute exposure to evening blue-enriched light impacts on human sleep

Light in the short wavelength range (blue light: 446-483 nm) elicits direct effects on human melatonin secretion, alertness and cognitive performance via non-image-forming photoreceptors. However, the impact of blue-enriched polychromatic light on human sleep architecture and sleep electroencephalographic activity remains fairly unknown. In this study we investigated sleep structure and sleep electroencephalographic characteristics of 30 healthy young participants (16 men, 14 women; age range 20-31 years) following 2 h of evening light exposure to polychromatic light at 6500 K, 2500 K and 3000 K. Sleep structure across the first three non-rapid eye movement non-rapid eye movement - rapid eye movement sleep cycles did not differ significantly with respect to the light conditions. All-night non-rapid eye movement sleep electroencephalographic power density indicated that exposure to light at 6500 K resulted in a tendency for less frontal non-rapid eye movement electroencephalographic power density, compared to light at 2500 K and 3000 K. The dynamics of non-rapid eye movement electroencephalographic slow wave activity (2.0-4.0 Hz), a functional index of homeostatic sleep pressure, were such that slow wave activity was reduced significantly during the first sleep cycle after light at 6500 K compared to light at 2500 K and 3000 K, particularly in the frontal derivation. Our data suggest that exposure to blue-enriched polychromatic light at relatively low room light levels impacts upon homeostatic sleep regulation, as indexed by reduction in frontal slow wave activity during the first non-rapid eye movement episode.

Release of ANP and fat oxidation in overweight persons during aerobic exercise in water

Exercise in water compared to land-based exercise (LE) results in a higher release of natriuretic peptides, which are involved in the regulation of exercise-induced adipose tissue lipolysis. The present study was performed to compare the release of atrial natriuretic peptide (ANP) and free fatty acids (FFA) during prolonged aerobic water-based exercise (WE) with the release after an identical LE. 14 untrained overweight subjects performed 2 steady state workload tests on the same ergometer in water and on land. Before and after exercise, venous blood samples were collected for measuring ANP, FFA, epinephrine, norepinephrine, insulin and glucose. The respiratory exchange ratio (RER) was determined for fat oxidation.The exercises resulted in a significant increase in ANP in LE (61%) and in WE (177%), and FFA increased about 3-fold in LE and WE with no significant difference between the groups. Epinephrine increased, while insulin decreased similarly in both groups. The RER values decreased during the exercises, but there was no significant difference between LE and WE. In conclusion, the higher ANP concentrations in WE had no additional effect on lipid mobilization, FFA release and fat oxidation. Moderate-intensity exercises in water offer no benefit regarding adipose tissue lipolysis in comparison to LE.

Effects of solifenacin in patients with neurogenic detrusor overactivity as a result of spinal cord lesion

STUDY DESIGN

Retrospective analysis.

OBJECTIVES

To investigate the urodynamic effects of solifenacin treatment for neurogenic detrusor overactivity (NDO) in patients with spinal cord injury (SCI).

SETTING

Paraplegic center in Switzerland.

METHODS

Retrospective analysis of case histories and urodynamic data of 35 SCI patients receiving solifenacin for treatment of NDO between 2008 and 2012. Patients were categorized as being at risk of renal damage when maximum detrusor pressure was >40 cm H2O or detrusor compliance was <20 ml cm(-1) H2O.

RESULTS

Solifenacin treatment was initiated 7.3 years after SCI. Most patients (63%) had already been taking other antimuscarinic drugs. After 13.1 months (median, interquartile range 6.1-19.5 months), solifenacin treatment had resulted in significant (P<0.03) improvements in bladder capacity (median +30.0 ml), maximum detrusor pressure (median -7.0 cm H2O), reflex volume (median +62.5 ml) and detrusor compliance (median +25.0 ml cm(-1) H2O). Furthermore, fewer patients presented with a risk of renal damage. However, this difference was not significant (P>0.1). The number of patients suffering from incontinence had not changed significantly. Eight and two patients discontinued solifenacin treatment as a result of insufficient efficacy and intolerable adverse events, respectively. One patient had discontinued solifenacin treatment without further explanation.

CONCLUSION

Solifenacin treatment significantly improved bladder capacity, detrusor compliance, reflex volume and maximum detrusor pressure. Solifenacin treatment seems to be an effective oral treatment of NDO after SCI.

120 THE DEVELOPMENTAL COMPETENCE OF TADPOLES PRODUCED IN VITRO FROM THE ENDANGERED DUSKY GOPHER FROG (RANA SEVOSA) USING EXOGENOUS HORMONE TREATMENT

Dusky gopher frogs once existed throughout the states of Mississippi, Alabama and Louisiana. Presently, the USA Fish and Wildlife Service estimates that there are less than 100 frogs left in the wild, with almost all of these residing in a single pond in Mississippi, making the dusky gopher frog America's most endangered frog species. Their habitat has been threatened by residential and forestry development, as well as from fire suppression and the decline of gopher tortoises, whose burrows the frogs use for shelter. The USA Fish and Wildlife Service brought the first dusky gopher frogs into captivity in 2001 and they have been kept at the Memphis Zoo since 2003 and at Omaha's Henry Doorly Zoo since 2004. Natural breeding attempts in captivity have been unsuccessful despite efforts to artificially mimic what is known to be the appropriate seasonal environmental (e.g. light, humidity, temperature) and social cues (e.g. calls from wild frogs during the breeding season) that stimulate reproduction in situ. Also, there was a concern about the incidences of abnormalities (e.g. spindly legs) from inadequate husbandry conditions (e.g. nutritional deficiencies) or diseases in tadpoles and froglets produced ex situ (e.g. dermomycoides). The objectives of this study were (1) to examine the developmental competence of tadpoles produced by exogenous hormone treatment for IVF to complete normal metamorphosis into viable froglets ex situ and (2) to determine the incidence of developmental abnormalities or dermomycoides in the froglets produced ex situ. Males and females were first separated by the identification of black male nuptial pads used during amplexus. Males and females were stimulated to spermiate and ovulate, respectively, using a variation of a standard amphibian hormonal stimulation protocol (Kouba et al. 2012 Reprod. Fertil. Dev. 24). As a result, more than 1460 viable tadpoles (61% of fertilized eggs) were produced from 18 segregated genetic pairings. To date, 602 (41%) of the tadpoles have completed normal metamorphosis into viable froglets (over 6 times the known existing population in situ), 51% were either culled to examine for dermomycoides or died for a variety of known (accidental) and unknown reasons (abnormal appendage development accounting for less than 7%) and 8% have yet to metamorphose after 9 months. The incidence of dermomycoides in the culled individuals was 100%; however, a study being conducted concurrently in their native habitat has confirmed that the organism does exist in situ with the dusky gopher frogs, which act as natural carriers. Efforts are currently in place to establish reintroduction programs for the dusky gopher froglets produced ex situ to increase the dwindling wild population now that tadpoles produced by IVF have been shown to be developmentally competent. In conclusion, IVF can be used to produce tadpoles of the dusky gopher frog with a low incidence of abnormalities, but the tadpoles were found to be carriers of the organism dermomycoides similar to their counterparts in the wild.

116 DEVELOPMENT OF ASSISTED REPRODUCTION TECHNOLOGIES FOR THE ENDANGERED MISSISSIPPI GOPHER FROG (RANA SEVOSA) AND SPERM TRANSFER FOR IN VITRO FERTILIZATION

Species-specific differences in breeding strategies and physiology have limited the application of assisted reproductive technologies (ART) for critically endangered amphibians in captive assurance colonies. In 2006, the Memphis Zoo (MZ) initiated a program to develop ART for the critically endangered Mississippi gopher frog after natural breeding failed. Standard gamete collection and IVF developed by MZ for reproducing endangered toads such as the Wyoming or boreal toad were applied to the gopher frog with little success, especially hormonal therapy for sperm production. Using the leopard frog as a model species for Ranids, we tested the time and dose dependence of a luteinizing hormone releasing hormone analogue (LHRHa) and hCG on sperm quantity and quality. Initial findings from the leopard frog study were critical in designing the study on gopher frogs. Our objectives were to (1) compare 2 different hormones administered intraperitoneal (500 IU hCG vs 15 μg LHRHa) or their combination on spermiation in gopher frogs; (2) develop in vivo oocyte maturation and ovulation protocols using LHRHa (15 μg) and hCG (500 IU); and (3) transfer this technology to another institution as proof of principle. In gopher frogs, 100 and 83% of the males produced sperm in response to the LHRHa and the combination treatment, respectively, whereas only 16% responded to hCG alone. Sperm concentration peaked at 1 h post-administration for all treatments, with the LHRH/hCG cocktail treatment producing the highest concentration of sperm (mean = 4.6 × 106 ± 1.2 × 106 sperm mL–1, n = 6). No differences in motility were observed between treatments (P > 0.05). For females, a series of priming hormones of hCG and LHRHa were given several months before an ovulatory hormone regimen resulting in ovulation by 100% of the females (n = 6), whereas animals not primed failed to ovulate (n = 4). These 3 separate priming and IVF trials conducted between 2008 and 2010 resulted in each female laying ∼2000 eggs, with an average fertilization rate of 76% for inseminated eggs and hundreds of tadpoles produced. These IVF tadpoles represent the first captive reproduction of gopher frogs and highlight how ART can be applied to conservation and genetic management of threatened species. Subsequently, we tested our IVF protocols on gopher frogs at Omaha's Henry Doorly Zoo using fresh (collected on site) and chilled, shipped sperm from MZ. We collected 6169 eggs from 9 hormone-primed females with all animals ovulating. A portion of the total eggs ovulated were inseminated, resulting in 2401 fertilized eggs (38.9% of total eggs collected) across 18 different male–female pairings leading to viable tadpoles. In addition, sperm transferred overnight from the MZ produced 202/441 fertilized eggs (46%). The transfer of this technology and production of endangered amphibians using chilled, shipped sperm from live animals is a conservation milestone that can be applied to other captive breeding programs.

Aerosolized semifluorinated alkanes as excipients are suitable for inhalative drug delivery--a pilot study

Semifluorinated alkanes (SFAs) have been described as potential excipients for pulmonary drug delivery, but proof of their efficacy is still lacking. We tested whether SFA formulations with the test drug ibuprofen can be nebulised and evaluated their pharmacokinetics. Physico-chemical properties of five different ibuprofen formulations were evaluated: an aqueous solution (H2O), two different SFAs (perfluorohexyloctane (F6H8), perfluorobutylpentane (F4H5)) with and without ethanol (SFA/EtOH). Nebulisation was performed with a jet catheter system. Inhalative characteristics were evaluated by laser diffraction. A confirmative animal study with an inhalative single-dose (6 mg/kg) of ibuprofen with each formulation was performed in anaesthetised healthy rabbits. Plasma samples at defined time points and lung tissue harvested after the 6-h study period were analyzed by HPLC-MS/MS. Pharmacokinetics were calculated using a non-compartment model. All formulations were nebulisable. No differences in aerodynamic diameters (MMAD) were detected between SFA and SFA/EtOH. The ibuprofen plasma concentration-time curve (AUC) was highest with F4H5/EtOH. In contrast, F6H8/EtOH had the highest deposition of ibuprofen into lung tissue but the lowest AUC. All tested SFA and SFA/EtOH formulations are suitable for inhalation. F4H5/EtOH formulations might be used for rapid systemic availability of drugs. F6H8/EtOH showed intrapulmonary deposition of the test drug.

Adult hippocampal neurogenesis and plasticity in the infrapyramidal bundle of the mossy fiber projection: I. Co-regulation by activity

Besides the massive plasticity at the level of synapses, we find in the hippocampus of adult mice and rats two systems with very strong macroscopic structural plasticity: adult neurogenesis, that is the lifelong generation of new granule cells, and dynamic changes in the mossy fibers linking the dentate gyrus to area CA3. In particular the anatomy of the infrapyramidal mossy fiber tract (IMF) changes in response to a variety of extrinsic and intrinsic stimuli. Because mossy fibers are the axons of granule cells, the question arises whether these two types of plasticity are linked. Using immunohistochemistry for markers associated with axonal growth and pro-opiomelanocortin (POMC)–GFP mice to visualize the post-mitotic maturation phase of adult hippocampal neurogenesis, we found that newly generated mossy fibers preferentially but not exclusively contribute to the IMF. The neurogenic stimulus of an enriched environment increased the volume of the IMF. In addition, the IMF grew with a time course consistent with axonal outgrowth from the newborn neurons after the induction of neurogenic seizures using kainate. These results indicate that two aspects of plasticity in the adult hippocampus, mossy fiber size and neurogenesis, are related and may share underlying mechanisms. In a second part of this study, published separately (Krebs et al., 2011) we have addressed the question of whether there is a shared genetics underlying both traits.

Adult Hippocampal Neurogenesis and Plasticity in the Infrapyramidal Bundle of the Mossy Fiber Projection: II. Genetic Covariation and Identification of Nos1 as Linking Candidate Gene

The hippocampus of adult rodents harbors two systems exhibiting structural plasticity beyond the level of synapses and dendrites. First, the persistent generation of granule cells (adult neurogenesis); second, dynamic changes in the mossy fibers (MF), in particular in the infrapyramidal mossy fiber (IMF) tract. Because MFs are the axons of granule cells, the question arises whether these two types of plasticity are linked. In the first part of this study (Römer et al., 2011) we have asked how both traits are regulated in relation to each other. In the present part, we asked whether, besides activity-dependent co-regulation, there would also be signs of genetic co-regulation and co-variance. For this purpose we used the BXD panel of recombinant inbred strains of mice, a unique genetic reference population that allows genetic association studies. In 31 BXD strains we did not find correlations between the traits describing the volume of the MF subfields and measures of adult neurogenesis. When we carried out quantitative trait locus mapping for these traits, we found that the map for IMF volume showed little overlap with the maps for the other parts of the projection or for adult neurogenesis, suggesting that to a large degree the IMF is regulated independently. The highest overlapping peak in the genome-wide association maps for IMF volume and the number of new neurons was on distal chromosome 5 (118.3-199.2 Mb) with an LRS score of 5.5 for IMF and 6.0 for new neurons. Within this interval we identified Nos1 (neuronal nitric oxide synthase) as a cis-acting (i.e., presumably autoregulatory) candidate gene. The expression of Nos1 is has been previously linked with both IMF and adult neurogenesis, supporting our findings. Despite explaining on its own very little of the variance in the highly multigenic traits studied, our results suggest Nos1 may play a part in the complex genetic control of adult neurogenesis and IMF morphology.

Semifluorinated alkanes--a new class of excipients suitable for pulmonary drug delivery

INTRODUCTION

Semifluorinated alkanes (SFAs) are considered as diblock molecules with fluorocarbon and hydrocarbon segments. Unlike Perfluorocarbons (PFCs), SFAs have the potential to dissolve several lipophilic or water-insoluble substances. This makes them possibly suitable as new excipients for inhalative liquid drug carrier systems.

PURPOSE

The aim of the study was to compare physico-chemical properties of different SFAs and then to test their respective effects in healthy rabbit lungs after nebulisation.

METHODS

Physico-chemical properties of four different SFAs, i.e. Perfluorobutylpentane (F4H5), Perfluorohexylhexane (F6H6), Perfluorohexyloctane (F6H8) and Perfluorohexyldodecane (F6H12) were measured. Based on these results, aerosol characteristics of two potential candidates suitable as excipients for pulmonary drug delivery, i.e. F6H8 and F4H5, were determined by laser light diffraction. Tracheotomised and ventilated New Zealand White rabbits were nebulised with either a high- or a low dose of SFAs (F6H8(low/high) and F4H5(low/high)) or saline (NaCl). Ventilated healthy animals served as controls (Sham). Arterial blood gases, lung mechanics, heart rate and blood pressure were recorded prior to nebulisation and in 30 min intervals during the 6-h study period.

RESULTS

Out of the four SFAs studied initially, no satisfactory behaviour as a solvent has to be expected because of low lipophilicity for F6H6. Output rate during aerosolisation was very low for F6H12. F6H8 and F4H5 presented comparable aerosolisation characteristics and lipophilicity and were therefore tested in the in vivo model. Aerosol therapy, either SFAs or saline, impaired paO2/FiO2 ratio, dynamic lung compliance and respiratory mechanics in all groups, except for F4H5(low) group which behaved like the control group (Sham). F4H5(low) had no adverse effects on gas exchange or pulmonary mechanics.

CONCLUSIONS

Perfluorobutylpentane (F4H5) in a low-dose application may be suitable as a new inhalable excipient in SFA-based pulmonary drug delivery systems for lipophilic or water-insoluble substances.

The bioclimatic envelope of the wolverine (Gulo gulo): do climatic constraints limit its geographic distribution?

We propose a fundamental geographic distribution for the wolverine ( Gulo gulo (L., 1758)) based on the hypothesis that the occurrence of wolverines is constrained by their obligate association with persistent spring snow cover for successful reproductive denning and by an upper limit of thermoneutrality. To investigate this hypothesis, we developed a composite of MODIS classified satellite images representing persistent snow cover from 24 April to 15 May, which encompasses the end of the wolverine’s reproductive denning period. To investigate the wolverine’s spatial relationship with average maximum August temperatures, we used interpolated temperature maps. We then compared and correlated these climatic factors with spatially referenced data on wolverine den sites and telemetry locations from North America and Fennoscandia, and our contemporary understanding of the wolverine’s circumboreal range. All 562 reproductive dens from Fennoscandia and North America occurred at sites with persistent spring snow cover. Ninety-five percent of summer and 86% of winter telemetry locations were concordant with spring snow coverage. Average maximum August temperature was a less effective predictor of wolverine presence, although wolverines preferred summer temperatures lower than those available. Reductions in spring snow cover associated with climatic warming will likely reduce the extent of wolverine habitat, with an associated loss of connectivity.

Tis21 expression marks not only populations of neurogenic precursor cells but also new postmitotic neurons in adult hippocampal neurogenesis

During embryonic cortical development, expression of Tis21 is associated with cell cycle lengthening and neurogenic divisions of progenitor cells. We here investigated if the expression pattern of Tis21 also correlates with the generation of new neurons in the adult hippocampus. We used Tis21 knock-in mice expressing green fluorescent protein (GFP) and studied Tis21-GFP expression together with markers of adult hippocampal neurogenesis in newly generated cells. We found that Tis21-GFP 1) was absent from the radial glia–like putative stem cells (type-1 cells), 2) first appeared in transient amplifying progenitor cells (type-2 and 3 cells), 3) did not colocalize with markers of early postmitotic maturation stage, 4) was expressed again in maturing neurons, and 5) finally decreased in mature granule cells. Our data show that, in the course of adult neurogenesis, Tis21 is expressed in a phase additional to the one of the embryonic neurogenesis. This additional phase of expression might be associated with a new and different function of Tis21 than during embryonic brain development, where no Tis21 is expressed in mature neurons. We hypothesize that this function is related to the final functional integration of the newborn neurons. Tis21 can thus serve as new marker for key stages of adult neurogenesis.

161 CRYOPRESERVATION OF CORN SNAKE, ELAPHE GUTATTA, SEMEN

The purpose of this investigation was to develop a protocol for cryopreserving snake semen using the corn snake, Elaphe gutatta, as the model species. This experiment is part of a five year investigation where the influences of diluents, cryoprotectants, cooling and thawing rates on sperm survival were studied. This report presents one protocol found to be effective for cryopreserving corn snake semen as determined by post-thaw motility parameters in vitro. Semen was collected by applying pressure to the lower abdomen and continuing distally towards the cloaca to remove any feces or urates. The cloaca was washed using PBS, then a more local pressure was applied to each side of the vent to cause the hemipenes to evert and subsequently ejaculate. The semen (approximately 5 μL) was then collected using a sterile transfer pipette, placed in 120 μL Biladyl A containing 20% egg yolk (Minitube, 13502/0501), and analyzed for motility, rate of forward progression (RFP; 0–5), and concentration. The semen was further diluted at room temperature at 1:1 v/v with Biladyl A containing 20% egg yolk and 34% Glycerol (Sigma, G2025), yielding a final concentration of 17% Glycerol. The diluted semen was then loaded into 250-μL straws and slowly cooled for 1 hour. The straws were then placed 1 inch above a liquid nitrogen bath for ten minutes and finally plunged into the nitrogen where it remained frozen. The cryopreserved semen was thawed by placing the straws into a 50°C water bath for 8 s, then emptied into microcentrifuge tubes and the sperm were evaluated for motility and RFP. The mean motility of the fresh samples was 72.5% (66.4–77.7%). The mean post-thaw motility of sperm over six trials was 27.1% (17.8–50.2%). The mean RFP was 0.75 (0.5–1.0). The differences between fresh and post-thawed mean motilities were shown to be significant using a chi-square analysis (P < 0.0001). Density gradient centrifugation (DGC) was applied in one trial where the semen had an initial post-thaw motility of 50.2% with an RFP of 0.5. After the centrifugation treatment, the motility increased to 64.8% with an RFP of 3. The DGC media was composed of 400 μL 45% Percoll (Sigma, P4937) layered over 400 μL 90% Percoll. The density gradients were centrifuged at 700g for 30 min after which time the pellets were washed in 500 μL pre-warmed TL Hepes Solution (Lonza, 04-616F) and centrifuged at 300g for 10 min to remove the Percoll. The resulting sperm pellets were then resuspended in a small volume of the pre-warmed Hepes. Thus far, the protocol using 17% Glycerol in Biladyl A with 20% egg yolk has proven to be the most successful for cryopreserving corn snake semen. The use of DGC enhanced the number of usable sperm leaving sperm of higher motility and RFP possibly due to the absence of seminal plasma or cryoprotective agents that may detrimentally affect sperm quality. There are no known reports of the use of DCG with snake semen. Further studies are underway to improve these results and successfully use cryopreserved snake semen for artificial insemination and cryobanking for the long-term genetic management of endangered snake species.

Initial treatment with fixed-dose combination rosiglitazone/glimepiride in patients with previously untreated type 2 diabetes

AIM

This study assessed the efficacy and safety of two different dosing regimens of fixed-dose combination (FDC) rosiglitazone (RSG) plus glimepiride (GLIM) compared with RSG or GLIM monotherapy in drug-naive subjects with type 2 diabetes mellitus (T2DM).

METHODS

Drug-naive subjects (n = 901) were enrolled into this 28-week, double-blind, parallel-group study if their glycosylated haemoglobin A(1c) (HbA(1c)) was >7.5% but <or=12%. Subjects were randomized to receive either GLIM [4 mg once daily (OD) maximal], RSG (8 mg OD maximal) or RSG/GLIM FDC regimen A (4 mg/4 mg OD maximal) or RSG/GLIM FDC regimen B (8 mg/4 mg OD maximal). Patients were assessed for efficacy and safety every 4 weeks for the first 12 weeks of the study, and at weeks 20 and 28. The primary efficacy endpoint was change in HbA(1c) from baseline. Key secondary endpoints included the proportion of patients achieving recommended HbA(1c) and fasting plasma glucose (FPG) targets; change from baseline in FPG, insulin, C-reactive protein (CRP), adiponectin, free fatty acids and lipids; and percentage change in homeostasis model assessment-estimated insulin sensitivity and beta-cell function. Safety evaluations included adverse-event (AE) monitoring and clinical laboratory evaluations.

RESULTS

At week 28, both RSG/GLIM FDC regimens significantly reduced HbA(1c) (mean +/- s.d.: -2.4 +/- 1.4% FDC regimen A; -2.5 +/- 1.4% FDC regimen B) to a greater extent than RSG (-1.8 +/- 1.5%) or GLIM (-1.7 +/- 1.4%) monotherapy (model-adjusted mean treatment difference, p < 0.0001 vs. both RSG and GLIM). Significantly more subjects achieved HbA(1c) target levels of <or=6.5 and <7% with either RSG/GLIM FDC regimen compared with RSG or GLIM alone (model-adjusted odds ratio, p < 0.0001 for both comparisons). Similarly, a significantly greater reduction in FPG levels was observed in subjects treated with the RSG/GLIM FDC [mean +/- s.d. (mg/dl): -69.5 +/- 57.5 FDC regimen A; -79.9 +/- 56.8 FDC regimen B) compared with RSG (-56.6 +/- 58.1) or GLIM (-42.2 +/- 66.1) monotherapy (model-adjusted mean treatment difference, p < 0.0001 for both comparisons). Improvement in CRP was also observed in subjects who were treated with a RSG/GLIM FDC or RSG monotherapy compared with GLIM monotherapy. RSG/GLIM FDC was generally well tolerated, with no new safety or tolerability issues identified from its monotherapy components, and a similar AE profile was observed across FDC regimens. The most commonly reported AE was hypoglycaemia, and the incidence of confirmed symptomatic hypoglycaemia (3.6-5.5%) was comparable among subjects treated with an RSG/GLIM FDC and GLIM monotherapy.

CONCLUSIONS

Compared with RSG or GLIM monotherapy, the RSG/GLIM FDC improved glycaemic control with no significant increased risk of hypoglycaemia. RSG/GLIM FDC provides an effective and well-tolerated treatment option for drug-naive individuals with T2DM.

Plasma levels of endothelin-1 after a pulmonary embolism of bone marrow fat

BACKGROUND

During orthopedic surgery, embolization of bone marrow fat can lead to potentially fatal, intra-operative cardiovascular deterioration. Vasoactive mediators may also be released from the bone marrow and contribute to these changes. Increased plasma levels of endothelin-1 (ET-1) have been observed after pulmonary air and thrombo-embolism. The role of ET-1 in the development of acute cardiovascular deterioration as a result of bone marrow fat embolization during vertebroplasty was therefore investigated.

METHODS

Bone cement was injected into three lumbar vertebrae of six sheep in order to force bone marrow fat into the circulation. Invasive blood pressures and heart rate were recorded continuously until 60 min after the last injection. Cardiac output, arterial and mixed venous blood gas parameters and plasma ET-1 concentrations were measured at selected time points. Post-mortem, lung biopsies were taken for analysis of intravascular fat.

RESULTS

Cement injections resulted in a sudden (within 1 min) and severe increase in pulmonary arterial pressure (>100%). Plasma concentrations of ET-1 started to increase after the second injection, but no significant changes were observed. Intravascular fat and bone marrow cells were present in all lung lobes.

CONCLUSION

Cement injections into vertebral bodies elicited fat embolism resulting in subsequent cardiovascular changes that were characterized by an increase in pulmonary arterial pressure. Cardiovascular complications as a result of bone marrow fat embolism should thus be considered in patients undergoing vertebroplasty. No significant changes in ET-1 plasma values were observed. Thus, ET-1 did not contribute to the acute cardiovascular changes after fat embolism.