Evaluation of new alternative methods for the identification of estrogenic, androgenic and steroidogenic effects: a comparative in vitro/in silico study.

A suite of in vitro assays and in silico models were evaluated to identify which best detected the endocrine-disrupting (ED) potential of 10 test chemicals according to their estrogenic, androgenic and steroidogenic (EAS) potential compared to the outcomes from ToxCast. In vitro methods included receptor-binding, CALUX transactivation, H295R steroidogenesis, aromatase activity inhibition and the Yeast oestrogen (YES) and Yeast androgen screen (YAS) assays. The impact of metabolism was also evaluated. The YES/YAS assays exhibited a high sensitivity for ER effects and, despite some challenges in predicting AR effects, is a good initial screening assay. Results from receptor-binding and CALUX assays generally correlated and were in accordance with classifications based on ToxCast assays. ER agonism and AR antagonism of benzyl butyl phthalate were abolished when CALUX assays included liver S9. In silico final calls were mostly in agreement with the in vitro assays, and predicted ER and AR effects well. The efficiency of the in silico models (reflecting applicability domains or inconclusive results) was 43-100%. The percentage of correct calls for ER (50-100%), AR (57-100%) and aromatase (33-100%) effects when compared to the final ToxCast call covered a wide range from highly reliable to less reliable models. In conclusion, Danish (Q)SAR, Opera, ADMET Lab LBD and ProToxII models demonstrated the best overall performance for ER and AR effects. These can be combined with the YES/YAS assays in an initial screen of chemicals in the early tiers of an NGRA to inform on the MoA and the design of mechanistic in vitro assays used later in the assessment. Inhibition of aromatase was best predicted by the Vega, AdmetLab and ProToxII models. Other mechanisms and exposure should be considered when making a conclusion with respect to ED effects.

Left hemisphere EEG coherence in infancy predicts infant declarative pointing and preschool epistemic language.

Pointing plays a central role in preverbal communication. While imperative pointing aims at influencing another person's behavior, declarative gestures serve to convey epistemic information and to share interest in an object. Further, the latter are hypothesized to be a precursor ability of epistemic language. So far, little is known about their underlying brain maturation processes. Therefore, the present study investigated the relation between brain maturation processes and the production of imperative and declarative motives as well as epistemic language in N = 32 infants. EEG coherence scores were measured at 14 months, imperative and declarative point production at 15 months and epistemic language at 48 months. Results of correlational analyses suggest distinct behavioral and neural patterns for imperative and declarative pointing, with declarative pointing being associated with the maturation of the left hemisphere. Further, EEG coherence measures of the left hemisphere at 14 months and declarative pointing at 15 months are related to individual differences in epistemic language skills at 48 months, independently of child IQ. In regression analyses, coherence measures of the left hemisphere prove to be the most important predictor of epistemic language skills. Thus, neural processes of the left hemisphere seem particularly relevant to social communication.

Elevated microRNA-181c and microRNA-30d levels in the enlarged amygdala of the valproic acid rat model of autism.

Autism spectrum disorders are severe neurodevelopmental disorders, marked by impairments in reciprocal social interaction, delays in early language and communication, and the presence of restrictive, repetitive and stereotyped behaviors. Accumulating evidence suggests that dysfunction of the amygdala may be partially responsible for the impairment of social behavior that is a hallmark feature of ASD. Our studies suggest that a valproic acid (VPA) rat model of ASD exhibits an enlargement of the amygdala as compared to controls rats, similar to that observed in adolescent ASD individuals. Since recent research suggests that altered neuronal development and morphology, as seen in ASD, may result from a common post-transcriptional process that is under tight regulation by microRNAs (miRs), we examined genome-wide transcriptomics expression in the amygdala of rats prenatally exposed to VPA, and detected elevated miR-181c and miR-30d expression levels as well as dysregulated expression of their cognate mRNA targets encoding proteins involved in neuronal system development. Furthermore, selective suppression of miR-181c function attenuates neurite outgrowth and branching, and results in reduced synaptic density in primary amygdalar neurons in vitro. Collectively, these results implicate the small non-coding miR-181c in neuronal morphology, and provide a framework of understanding how dysregulation of a neurodevelopmentally relevant miR in the amygdala may contribute to the pathophysiology of ASD.

Same or different? ERP correlates of pretense and false belief reasoning in children.

Pretend play, emerging at about 18 months, and explicit false belief (FB) understanding, arising around 4 years, constitute two pivotal milestones in the development of a Theory of Mind since both involve the ability to separate real from non-real content. The developmental lag has evoked vivid discussion with respect to whether or not pretense (PT) involves a metarepresentational understanding similar to FB. However, in children PT and FB have not yet been contrasted on a neural level to reveal whether they are subserved by the same neurocognitive mechanism. Therefore, the present event-related potential (ERP) study compared PT to a FB and to a non-mental control condition in 6- to 8-year-old children. Results revealed distinct ERP components for PT and FB. PT elicited a parietal P2, which was assumed to reflect the detection of incongruence, and a negative frontal slow wave (290-600 ms), which was associated with the identification of the intention underlying the pretend behavior. In contrast, FB evoked the characteristic positive fronto-central late slow wave (290-920 ms) that is supposed to indicate metarepresentation. Further, the broad distribution of the anterior slow-wave patterns associated with PT and FB reasoning was assumed to reflect the ongoing structural development and neural specialization of the respective areas, indicating the developmental progress in conceptualizing the mental domain. Given the differences in latency, polarity, and topography, PT and FB seem to rely on distinct neural substrates in children. The early negative frontal slow wave indicates that for PT reasoning children may use simple mentalizing processes such as intention processing, whereas the late positive slow-wave shows that for FB children may engage in metarepresentational processing. Therefore, the present findings seem to substantiate theoretical accounts postulating simple mentalistic reasoning for PT in children.

Impedance spectroscopy on ceramic materials at high temperatures, considering stray fields and electromagnetic noise.

Impedance spectroscopy of many ceramics is a challenge due to their high electrical resistance. Small disturbances can significantly alter the measuring results. In the present paper, it is shown how impedance measurements can be performed in an electromagnetically noisy ac furnace, using consequent Faraday shielding of the sample and the electrical connections. As example, the conductivity data of alumina was measured between room temperature and 1000 °C and compared to literature data. In addition, a correction method for the calculation of permittivity was developed to consider the stray fields in the sample-electrode setup. The distribution of the electrical field was simulated by finite element (FE) methods for different sample geometries and electrode arrangements. The deviations from the behavior of an ideal plate capacitor follow a linear trend and are in the order of 5% to 20% for an experimentally reasonable range of sample thicknesses. To check the theoretical results experimentally, alumina samples of varying thickness were measured. The customary calculation of permittivity leads to a clear trend with sample thickness, whereas the correction from the FE-simulation produces almost constant values of the relative permittivity.

[Structure of amyloid fibrils]. / Struktur von Amyloidfibrillen.

Amyloid fibrils are structurally defined as fibrillar polypeptide aggregates with a characteristic cross-beta structure. Such fibrils can be formed by certain polypeptide sequences in the human body and by numerous polypeptide sequences in vitro. All amyloid fibrils possess a structural spine that is formed by a cross-beta structure. This structure is stabilized by hydrogen bonds between the polypeptide backbone. In recent years, various biophysical techniques, such as X-ray crystallography, solid state nuclear magnetic resonance spectroscopy and electron cryo-microscopy have provided insights into the structural organization of amyloid fibrils. This review presents an overview of important results obtained with these methods.

[Negative-pressure pulmonary edema (NPPE)]. / Das pulmonale Negativdrucködem.

Negative-pressure pulmonary edema (NPPE) is a clinical entity of anaesthesiologic relevance, perioperatively caused by obstruction of the conductive airways (upper airway obstruction, UAO) due to laryngospasm in approx. 50% of the cases, its early recognition and treatment by the anaesthesist is mandatory. NPPE, also addressed as post-obstructive pulmonary edema (POPE) presents in most cases as a complex of symptoms with rapid onset, consisting of acute respiratory failure with dyspnea, tachypnea, and strained respiratory efforts. Additional signs are paradoxe ventilation, pink frothy sputum, stridor, and severe agitation. UAO produce extreme reduction of intrathoracic pressure during spontaneous ventilation, consecutively causing increase in venous return to the right ventricle and in intrathoracic blood volume, resulting in elevated hydrostatic pressures and interstitial transudation of fluids. Partially due to largely differing criteria used for diagnosis, opinions about incidence and prevalence of NPPE are unhomogenous in medical literature. It has been shown that generation of NPPE is not only limited to patients being intubated and ventilated, but occurs also in patients requiring higher fractions of oxygen.

The dependency of expiratory airway collapse on pump system and flow rate in liquid ventilated rabbits.

PURPOSE: To evaluate the influence of pump system and flow pattern on expiratory airway collapse (EAC) in total perfluorocarbon ventilation. - METHODS: Prospective, controlled, randomized animal trial for determination of (1) post-mortem changes by repeated expiration procedures (EP) with a constant flow piston pump (PP) before and after sacrifice (n = 8 rabbits), (2) differences between pump systems by subjecting animals to both PP and roller pump (RP) circuits for expiration (n = 16 rabbits). EP were performed using a servo-controlled shut-off at airway pressures < 25 cm H subset 2O randomly with either pump at different flows. - RESULTS: Expired volumes before and after sacrifice were not significantly different. PP and RP revealed identical mean flows, while significantly more liquid was drained using PP (p<0.05). Increasing differences towards higher flow rates indicated profound flow pulsatility in RP. - CONCLUSIONS: (1) post-mortem changes in expired volumes are not significant, (2) EAC is related to flow rate and pump system; (3) relationship between expiratory flow rate and drainable liquid volume is linear inverse; (4) PP provides higher drainage than RP. - SUMMARY STATEMENT: Expiratory airway collapse is related to flow rate and pump system, post mortem changes in expirable volumes are not significant. Relationship between expiratory flow rate and drainable liquid volume is linear inverse, piston pump expiration provides higher drainage volumes than roller pump expiration.

[Extracorporeal membrane oxygenation (ECMO) in adults]. / Extrakorporale Membranoxygenierung (ECMO) im Erwachsenenalter.

Despite ongoing discussions, ECMO (extracorporeal membrane oxygenation) has become an important part of treatment options in acute lung injury and ARDS (acute respiratory distress syndrome) even in adults. On the other hand, none of the two RCT (randomized controlled trial) studies resulted in reduced letality of the artificial lung therapy when compared to convention treatment. Both authors concluded, that ECMO is not recommended in ARDS. Meanwhile experience with ECMO in adults is extensive in various institutions worldwide, exceeding 1000 patients by the end of 2001. Growing experience and improved technical equipment reduce the rate of technical complications substantially. However, for different reasons ECMO incidence in adults is progressively decreasing in recent years. Inclusion and exclusion criteria vary among different ECMO centers. Potential reversibility of lung injury and persisting life-threatening gas exchange disorder under maximal conventional therapy are commonly seen as requirements for ECMO therapy. ECMO criteria are Murray lung injury score >3.5 (chest x-ray, PaO2/FiO2-index, static compliance Cstat, PEEP), Morel-classification >3 (chest x-ray, AaDO2/FiO2-index, Cstat, PEEP), AaDO2 >600mmHg, intrapulmonal shunt QS/QT >30%, and increase in extravascular lung water >15 ml/kg bodyweight. Commonly accepted absolute contraindications are (1) severely consuming disorders with poor prognosis, (2) CNS damage with poor prognosis, (3) advanced chronic lung disorders, and (4) progressive multiple organ failure. Relative contraindications are immunosuppresion, active bleeding, age over 60 years, and days on mechanical ventilation. In our experience, early contact to an ECMO reference center can optimise early identification of patients which benefit from ECMO, as well as treatment and transportation modalities, and improves outcome. Due to high technical and personal requirements and decreasing incidence in the adult sector, ECMO should be limited to a small number of reference centers with substantial experience in extracorporeal circulation.

The specificity of infant emotional expression for emotion perception.

Attachment theory emphasizes the role of negative emotional expression in infancy for establishing proximity to and care of the caregiver. According to Lang's biphasic model of emotions protective reflexes (e.g. startle response) are primed if a defensive motivational set is activated. The aim of the study was to examine whether the perception of an infant emotional expression can prime such defensive behavior. The sample consisted of 48 university students. Startle reflex, corrugator and zygomatic EMG activity and subjective ratings of valence and arousal were assessed as a response to presentation of pictures of different emotional valence. Affective startle modulation was obtained when probes were presented during pictures of the International Affective Pictures System replicating previous findings. By contrast, negative infant emotion pictures did not prompt an augmentation of the startle response, although both the subjective ratings and the mimic EMG activity indicated a clear differentiation between negative and positive infant pictures. This pattern of findings was found only in a between-subject design, but not when the two picture sets were presented in the same session, indicating an interference of contrasting content of pictures.

Motor response detection using fiber optics during functional magnetic resonance imaging.

Data acquisition during functional magnetic resonance imaging and magnetoencephalography studies is easily disturbed by metallic and magnetic devices. Nevertheless, recording motor responses during many neuropsychological studies is essential. In this paper, we describe the design and construction of a nonmetallic, nonmagnetic motor response recording device that uses fiber optics to obtain interference-free data.

Development and application of a double-piston configured, total-liquid ventilatory support device.

OBJECTIVE: Perfluorocarbon liquid ventilation has been shown to enhance pulmonary mechanics and gas exchange in the setting of respiratory failure. To optimize the total liquid ventilation process, we developed a volume-limited, time-cycled liquid ventilatory support, consisting of an electrically actuated, microprocessor-controlled, double-cylinder, piston pump with two separate limbs for active inspiration and expiration. DESIGN: Prospective, controlled, animal laboratory study, involving sequential application of conventional gas ventilation, partial ventilation (PLV), and total liquid ventilation (TLV). SETTING: Research facility at a university medical center. SUBJECTS: A total of 12 normal adult New Zealand rabbits weighing 3.25+/-0.1 kg. INTERVENTIONS: Anesthestized rabbits were supported with gas ventilation for 30 mins (respiratory rate, 20 cycles/min; peak inspiratory pressure, 15 cm H2O; end-expiratory pressure, 5 cm H2O), then PLV was established with perflubron (12 mL/kg). After 15 mins, TLV was instituted (tidal volume, 18 mL/kg; respiratory rate, 7 cycles/min; inspiratory/expiratory ratio, 1:2 cycles/min). After 4 hrs of TLV, PLV was re-established. MEASUREMENTS AND MAIN RESULTS: Of 12 animals, nine survived the 4-hr TLV period. During TLV, mean values +/- SEM were as follows: PaO2, 363+/-30 torr; PaCO2, 39+/-1.5 torr; pH, 7.39+/-0.01; static peak inspiratory pressure, 13.2+/-0.2 cm H2O; static endexpiratory pressure, 5.5+/-0.1 cm H2O. No significant changes were observed. When compared with gas ventilation and PLV, significant increases occurred in mean arterial pressure (62.4+/-3.5 torr vs. 74.0+/-1.2 torr) and central venous pressure (5.6+/-0.7 cm H2O vs. 7.8+/-0.2 cm H2O) (p < .05). CONCLUSIONS: Total liquid ventilation can be performed successfully utilizing piston pumps with active expiration. Considering the enhanced flow profiles, this device configuration provides advantages over others.

Reduced platelet activation and thrombosis in extracorporeal circuits coated with nitric oxide release polymers.

OBJECTIVE: To determine whether the use of nitric oxide (NO)-releasing polymers coated onto the inner surface of extracorporeal circuits can reduce platelet consumption and activation in the absence of systemic heparinization using a rabbit model of venovenous extracorporeal circulation. DESIGN: Prospective, controlled trial. SETTING: Research laboratory at an academic medical institution. SUBJECTS: New Zealand White Rabbits. INTERVENTIONS: Anesthetized, tracheotomized, and ventilated New Zealand White rabbits were injected with freshly prepared, 111In(oxine)3 labeled single donor platelets through the external jugular vein. After baseline measurements, these animals were placed on venovenous extracorporeal circulation through a 1-m control circuit or NO test circuit for 4 hrs at a blood flow rate of 109-118 mL/min via roller pump. Four groups were studied: systemically heparinized control circuits, systemically heparinized NO test circuits, nonheparinized control circuits, and nonheparinized NO test circuits. Platelet counts, fibrinogen levels, and plasma free indium levels were measured hourly. Circuits were rinsed and retained for gamma counting after the 4-hr run or when the circuit clotted. Four animals, one from each group, did not receive radiolabeled platelets so that the circuits could be preserved for scanning electron microscopic examination after the 4-hr study. MEASUREMENTS AND MAIN RESULTS: Platelet consumption was significantly reduced in both the heparinized and nonheparinized NO test groups when compared with the controls (p < .0001 and p < .0004, respectively). Platelet adhesion to the extracorporeal circuits was significantly reduced in the nonheparinized test circuits when compared with the controls (p < .05). Scanning electron microscopic examination of the circuits revealed that in the absence of heparin and in the presence of a NO-releasing surface, platelets retained their spherical nonactivated shape. CONCLUSIONS: The incorporation of NO into the surface of extracorporeal circuits reduces platelet consumption and eliminates the need for systemic heparinization in a rabbit model of extracorporeal circulation.

Recombinant Kunitz protease inhibitory domain of the amyloid beta-protein precursor as an anticoagulant in venovenous extracorporeal circulation in rabbits.

Investigations were performed to characterize a recombinant Kunitz protease inhibitory domain of the amyloid beta-protein precursor (rKPI) as anticoagulants. After a single intravenous infusion of wild type rKPI into dogs, its elimination fit a two compartment model with a t1/2alpha and t1/2beta of 5 and 77 min, respectively. Further investigations determined if a variant form of rKPI with 178-fold more potent anti-factor Xa activity (rKPI-DD135, Ki = 0.9 nM) could serve as an anticoagulant in a rabbit model of extracorporeal circulation using a venovenous shunt. A prospective investigation was initiated to compare standard heparin (n = 8) at 400 U/kg with different infusion concentrations of rKPI-DD135. After a single intravenous infusion of 1.89 mg/kg of rKPI-DD135 followed by a constant infusion at 0.003 (n = 3), 0.03 (n = 7), or 0.3 (n = 5) mg/kg/min, the anti-factor Xa activity of the animals' plasma rapidly reaches a steady state for the two lower infusion concentrations of the agent. All infusions of rKPI-DD135 prolong the activated clotting time with less variation than that seen with heparin administration. rKPI-DD135 anticoagulation does not prevent a drop in the platelet counts. Fibrinogen levels decrease only slightly when the circuit is anticoagulated with rKPI-DD135. rKPI-DD135 markedly prolongs the APTT, has little effect on the PT, and reduces plasma prekallikrein and plasminogen activation. The 0.3 mg/kg/min infusion concentration of rKPI-DD135 results in reduced deposition of 111Indium-labeled platelets on the circuit when compared to heparin. Last, after a steady state level is achieved, 60% of the plasma anti-factor Xa activity of rKPI-DD135 is eliminated within 60 min after stopping the infusion. These data show the rKPI-DD135 can provide single agent anticoagulation in a rabbit extracorporeal circuit. Development of short acting factor Xa inhibitors may be useful anticoagulants for cardiopulmonary bypass.

Effect of blood flow rate on thrombogenesis in a rabbit extracorporeal circulation model.

Blood flow is believed to affect the thrombogenicity of extracorporeal circulation (ECC). The purpose of this study was to look at the relationship between blood flow and thrombogenicity in a rabbit model of ECC. Rabbits were anesthetized and systematically heparinized. Bilateral jugular cannulation was performed, and the animals were placed on venovenous ECC. The circuits were composed of 1 m of 1/4 inch size surgical grade polyvinylchloride (PVC) tubing. ECC was maintained for 4 hours. Three experimental groups were studied: a high flow group (n=7; flow rate: 30 ml/min/Kg), low flow group (n=7; flow rate: 10 ml/mg/Kg), and no ECC group (n=7). Platelet count, fibrinogen concentration, PaO2/FiO2, and postmortem findings were evaluated. Platelet consumption was higher with high flow, and fibrinogen consumption was higher with low flow.

[Partial liquid ventilation]. / Partielle Flüssigkeitsventilation (partial liquid ventilation).

Partial liquid ventilation (PLV) is a relatively new therapeutic approach to acute lung injury (ALI) and the acute respiratory distress syndrome (ARDS). The idea of combining the intrapulmonary application of an oxygen-carrying substance and positive pressure ventilation was introduced by Fuhrman in 1991 and originally called perfluorocarbon-associated gas exchange (PAGE). Nowadays, the technique is mostly known as partial liquid ventilation (PLV). The efficacy of PVL treatment has been demonstrated in numerous animal studies in different models of lung injury. The results of those studies led to multicenter phase I-II studies in patients of all age groups in the United States and Canada. Recently, the first randomized, controlled study in 90 adult patients suffering from ALI and ARDS was completed and first results have been published. Comparison of overall mortality and number of ventilator-free days (VFD's) in a 28-day period showed no differences between PLV and conventionally treated patients. A post-hoc stratification by age (< 55 years) demonstrated a tendency to lower mortality (PLV 25.6%; CMV 36.8%) and a significant increase of VFD (PLV 8.95 days; CMV 4.11 days; p = 0.03) in PLV when compared to conventionally treated patients. Perfluorocarbons (PFCs) are chemically stable and inert. They are mostly eliminated via exhalation (> 99%). The unique physicochemical properties of PFCs permit access to atelectatic, non-ventilated lung areas, enhance gas exchange and decrease inflammation. The dense PFCs prevent the endexpiratory collapse of alveoli and reestablish functional residual capacity (FRC). Comparable to positive endexpiratory pressure (PEEP), these effects have been described as "liquid or fluid PEEP". These properties offer a new approach to the underlying pathophysiology of ALI and ARDS. In addition, the combination with other therapeutic approaches to ALI and ARDS like high-frequency oscillations (HFO), inhaled nitric oxide (NO) therapy, and surfactant replacement can be considered and is already the subject of recent publications. However, combination therapy is still experimental and further investigation is necessary to evaluate efficacy and potential risks. Many questions still exist which need to be answered by experimental as well as human pilot studies. Based on these studies, the results of ongoing human trials can be assessed properly and new multicenter trials can be planned effectively.

[Liquid ventilation with perfluorocarbons]. / Flüssigkeitsventilation mit Perfluorcarbonen.

Clark and Gollan demonstrated impressively in 1966 the ability of perfluorchemicals (PFCs) to transport oxygen and to provide gas exchange across the alveolar capillary membrane. PFCs are used for two major medical indications: as artificial blood substitutes and as a medium for liquid ventilation. The PFC perflubron is additionally used as a contrast medium for diagnostic radiologic procedures. For the intravenous application perfluorocarbons have to be emulgated in phospholipids for the intrapulmonary application the sterile pure solution is used. Liquid ventilation can either be performed by a method known as total liquid ventilation (TLV), in which a device is utilised to ventilate with perfluorocarbon the previously perfluorocarbon-filled lung, or as partial liquid ventilation (PLV) in which a conventional mechanical gas ventilator is used to gas ventilate the partially perfluorocarbon-filled lung. A number of studies have demonstrated the efficacy of perfluorocarbon liquid ventilation in improving gas exchange and pulmonary function in a number of animal species in the setting of acute respiratory failure. In 1989 Greenspan reported on the first human liquid ventilation experience in a neonate. More recently human experiences for neonatal, paediatric and adult patients with acute lung injury have been reported. Since 1995 an FDA-approved study to examine the efficacy of PLV in severe respiratory failure in patients of all ages has been undertaken in the United States. The number of PLV-treated patients is still small; if PLV demonstrates its efficacy even in the ongoing human studies, it might be a very effective additional tool for treating severe acute lung injury.