Evaluating consumptive and nonconsumptive predator effects on prey density using field time-series data.

Determining the degree to which predation affects prey abundance in natural communities constitutes a key goal of ecological research. Predators can affect prey through both consumptive effects (CEs) and nonconsumptive effects (NCEs), although the contributions of each mechanism to the density of prey populations remain largely hypothetical in most systems. Common statistical methods applied to time-series data cannot elucidate the mechanisms responsible for hypothesized predator effects on prey density (e.g., differentiate CEs from NCEs), nor can they provide parameters for predictive models. State-space models (SSMs) applied to time-series data offer a way to meet these goals. Here, we employ SSMs to assess effects of an invasive predatory zooplankter, Bythotrephes longimanus, on an important prey species, Daphnia mendotae, in Lake Michigan. We fit mechanistic models in an SSM framework to seasonal time series (1994-2012) using a recently developed, maximum-likelihood-based optimization method, iterated filtering, which can overcome challenges in ecological data (e.g., nonlinearities, measurement error, and irregular sampling intervals). Our results indicate that B. longimanus strongly influences D. mendotae dynamics, with mean annual peak densities of B. longimanus observed in Lake Michigan estimated to cause a 61% reduction in D. mendotae population growth rate and a 59% reduction in peak biomass density. Further, the observed B. longimanus effect is most consistent with an NCE via reduced birth rates. The SSM approach also provided estimates for key biological parameters (e.g., demographic rates) and the contribution of dynamic stochasticity and measurement error. Our study therefore provides evidence derived directly from survey data that the invasive zooplankter B. longimanus is affecting zooplankton demographics and offer parameter estimates needed to inform predictive models that explore the effect of B. longimanus under different scenarios, such as climate change.

Real-time inverse kinematics for the upper limb: a model-based algorithm using segment orientations.

BACKGROUND: Model based analysis of human upper limb movements has key importance in understanding the motor control processes of our nervous system. Various simulation software packages have been developed over the years to perform model based analysis. These packages provide computationally intensive-and therefore off-line-solutions to calculate the anatomical joint angles from motion captured raw measurement data (also referred as inverse kinematics). In addition, recent developments in inertial motion sensing technology show that it may replace large, immobile and expensive optical systems with small, mobile and cheaper solutions in cases when a laboratory-free measurement setup is needed. The objective of the presented work is to extend the workflow of measurement and analysis of human arm movements with an algorithm that allows accurate and real-time estimation of anatomical joint angles for a widely used OpenSim upper limb kinematic model when inertial sensors are used for movement recording. METHODS: The internal structure of the selected upper limb model is analyzed and used as the underlying platform for the development of the proposed algorithm. Based on this structure, a prototype marker set is constructed that facilitates the reconstruction of model-based joint angles using orientation data directly available from inertial measurement systems. The mathematical formulation of the reconstruction algorithm is presented along with the validation of the algorithm on various platforms, including embedded environments. RESULTS: Execution performance tables of the proposed algorithm show significant improvement on all tested platforms. Compared to OpenSim's Inverse Kinematics tool 50-15,000x speedup is achieved while maintaining numerical accuracy. CONCLUSIONS: The proposed algorithm is capable of real-time reconstruction of standardized anatomical joint angles even in embedded environments, establishing a new way for complex applications to take advantage of accurate and fast model-based inverse kinematics calculations.

Surgical ventricular reconstruction and subendocardial resection for the treatment of refractory ventricular tachycardia.

We describe a case of 64-year-old female patient with ventricular tachycardia intractable to medical treatment and acute heart failure following myocardial infarction. Emergency surgical ventricular reconstruction and subendocardial resection was undertaken. We discuss the option of surgical intervention in this difficult and unusual clinical scenario.

Motor synergies during manual tracking differ between familiar and unfamiliar trajectories.

Synergistic control of the effector space allows high precision in task-relevant degrees of freedom, while noise is limited to task-irrelevant degrees of freedom. The present study investigates whether this typical structure of the variance-covariance matrix of the joint angles during manual tracking differs between familiar and unfamiliar trajectories. Subjects tracked a target moving in 2D on a graphics tablet with a hand-held pen, while their arm movements were not restricted. Subjects familiarized themselves with one target trajectory during an initial training block with 40 periodic trials. In the following test block, this familiar trajectory and several unfamiliar trajectories were presented in a mixed-block design to study prediction effects at the level of endpoint and joint trajectories. The differences in the synergistic control of arm movements were analyzed using the "uncontrolled manifold method." The results showed smaller variances and weaker motor synergies during tracking of familiar trajectories than during tracking of unfamiliar trajectories. The decrease in the synergy index was due to a stronger decrease in the variance irrelevant than of the variance relevant for pen position. In the context of motor control theory, these results suggest that tracking movements on familiar and unfamiliar target trajectories do not only differ in the available knowledge about target location but also apply different strategies to control the effector space.

Ketamine-induced catalepsy during adult sedation in the Emergency Department.

BACKGROUND: Ketamine continues to rise in popularity for procedural sedation in the Emergency Department (ED) for both adult and pediatric patients. The medication has a good safety profile and is well tolerated in the majority of patients. However, the Emergency Physician should be aware of the full range of side-effects that may be encountered, so as to best anticipate and prepare for potential complications. OBJECTIVES: We describe two cases of catalepsy (muscle hypertonia with dissociation) in patients undergoing sedation with ketamine. CASE REPORT: In the first case, a patient presented to the ED after a prehospital awake nasal intubation for an exacerbation of chronic obstructive pulmonary disease. After sedation with ketamine, he was extubated and transitioned to bi-level positive pressure ventilation. Shortly after receiving ketamine, he exhibited severe muscular hypertonia of the upper extremities with facial grimacing. A second patient underwent ketamine sedation for reduction of a shoulder dislocation. After medication administration, he exhibited full body muscular hypertonicity, interfering briefly with the procedure. In both patients, catalepsy resolved spontaneously. CONCLUSIONS: Ketamine-induced catalepsy is a self-limited side-effect that has the potential to interfere with procedures performed under sedation.

Medicinal chemistry of 5-HT5A receptor ligands: a receptor subtype with unique therapeutical potential.

Although the 5-HT(5) receptor subfamily was discovered more than 15 years ago, it is unambiguously the least known 5-HT receptor subtype. The G(i)/G(0)-mediated signal transduction and its intensive presence in raphe and other brainstem and pons nuclei suggest mechanisms similar to those of 5-HT(1) receptors, the ligands of which are already applied in the treatment of e.g. anxiety and migraine. In addition, a unique coupling and inhibition of adenosine diphosphate-ribosyl cyclase have also been described. High concentrations of 5-HT(5) receptor in other key regions including, e.g. locus coeruleus, nucleus of the solitary tract, arcuate and suprachiasmatic nuclei of the hypothalamus indicate a wide range of physiological effects, thus its ligands are potential drug candidates in various areas, e.g. anxiety, sleep, incontinence, food intake, learning and memory, pain or chemoreception pathways. These findings have motivated several institutes and pharmaceutical companies to participate in the research of this field. Despite extensive research, no selective agonist and only two selective antagonists have been identified until now. Beyond these compounds, the present review provides a complete overview on all other published 5-HT(5A) receptor ligands as well as on the structure, function, distribution, genetics and possible therapeutic applications of this receptor.

Orientational ordering and low-temperature libration in the rotor-stator cocrystals of fullerenes and cubane.

Cocrystals of cubane and fullerenes, C60-cubane and C70-cubane, show distinct rotational ordering transitions. We studied the corresponding structural changes with temperature-dependent X-ray diffraction and the thermodynamics of the phase transitions with adiabatic microcalorimetry and differential scanning calorimetry. C60-cubane has one phase transition around 130 K from a high-temperature fcc phase with freely rotating C60 to a low-temperature orthorombic phase in which the fullerene rotation is frozen. The corresponding enthalpy change is approximately 1170 J/mol, and the entropy change is 9.6 J/(mol K). C70-cubane has two phase transitions. Around 380 K, the high-temperature fcc phase with freely rotating C70 transforms into a bct phase in which the C70 rotates uniaxially around an axis that precesses around the c direction with a full opening angle of 40 degree. Around 170 K, the uniaxial rotation also freezes out, with an accompanying structural transition to monoclinic and enthalpy and entropy changes of 620 J/mol and 8.7 J/(mol K), respectively. The low-temperature specific heat was analyzed in terms of the Debye-Einstein model to estimate the librational energies of the fullerenes and Debye temperatures. We found very similar values for the two cocrystals, approximately Elib = 2.2 meV and TDebye = 23 K. For reference, we also measured the specific heats of pure C60 and C70 and found Elib = 2.96 meV and TDebye = 32 K for C60 and Elib = 1.9 meV and TDebye = 20 K for C70.

Non-invasive measurement of peripheral venous oxygen saturation using a new venous oximetry method: evaluation during bypass in heart surgery.

Monitoring of mixed venous oxygen saturation (SvO(2)) is currently performed using invasive fibre-optic catheters. This procedure is not without risk as complications may arise from catheterization. This paper describes an alternative, non-invasive method of monitoring peripheral venous oxygen saturation (SxvO(2)) which, although it cannot replace pulmonary artery catheters, can serve as an adjunct/early warning indicator of when there is an imbalance in oxygen supply and demand. The technique requires the generation of an artificial venous pulse at the finger, thereby causing modulation of the venous blood volume within the digit. The blood volume changes are monitored using an optical sensor. Just as pulse oximetry utilizes the natural arterial pulse to perform a spectrophotometric analysis of the peripheral blood in order to estimate the arterial blood oxygen saturation, the proposed venous oximetry technique uses the artificially generated venous pulse to estimate SxvO(2). A prototype device was tested in a pilot study with patients undergoing heart surgery. Data from this study support the notion that the method is capable of tracking haemodynamic changes and suggests the technique is worthy of further development and evaluation.

Experimental studies on the antitussive properties of the new xanthine derivative 1H-purine-2,6-dione, 3,7-dihydro-3-methyl-7[(5-methyl-1,2,4-oxadiazol-3-yl) methyl]. 3rd communication: examinations on opioid mechanisms and physical drug dependence.

CH-13584 (formerly: KHL-8425, 1H-purine-2,6-dione, 3,7-dihydro-3-methyl-7[(5-methyl-1,2,4-oxadiazol-3-yl)methyl], CAS 115779-20-9) showed antitussive effect on the citric acid spray-induced cough model. The antitussive effect of p.o. CH-13584 was antagonised by i.m. or intracerebroventricular (i.c.v.) naloxone, i.m. nor-binaltorphimine or s.c. beta-funaltrexamine. Intracerebroventricular administration of CH-13584 induced long-lasting antitussive effect which was antagonised by coadministration of i.c.v. naloxone. CH-13584 did not bind to opioid mu, delta, kappa receptor in vitro or inhibit the [3H]diprenorphine binding in vivo. Two-week treatment with CH-13584 up to the dose of 100 mg/kg p.o. did not produce autonomic and behavioural signs of withdrawal induced either by drug withdrawal or by naloxone injection, while morphine and codeine induced characteristic opioid-type physical dependence in rats.

Vincamine and vincanol are potent blockers of voltage-gated Na+ channels.

The effects of three vinca derivatives on [3H]batrachotoxin binding in rat cortical synaptosomes, on the inhibition of whole-cell Na+ currents evoked in voltage-clamped cortical neurones of the rat, on the protection against veratridine-induced cell death in cortical cultures and on the maximal electroshock-induced seizures in mice were compared. Vinpocetine, vincamine and vincanol reduced [3H]batrachotoxin binding with IC50 values of 0.34, 1.9 and 10.7 microM, blocked Na+ currents with IC50 values of 44.72 and 40 microM, and protected cortical against veratridine-induced cell death with IC50 values of 0.49, 26 and 33 microM, respectively. Upon i.p. administration, vinpocetine, vincamine and vincanol attenuated maximal electric shock-induced convulsions in a dose-dependent manner with ED50 values of 27, 15.4 and 14.6 mg/kg, respectively. The present findings indicate that the three vinca derivatives are potent blockers of voltage-gated Na+ channels, a mechanism that may contribute at least in part to the pharmacological/therapeutic benefit of these drugs.

Neonatal treatment with phenobarbital, zixoryn and chloramphenicol lack of imprinting effect of zixoryn on microsomal enzyme activities.

Two potent microsomal enzyme inducing agents, phenobarbital and flumecinol (Zixoryn) as well as the microsomal enzyme inhibitor chloramphenicol (Chlorocid) were given subcutaneously to newborn rats in the first 5 days of their life. Microsomal cytochrome P-450 and b5 content and various cytochrome P-450 and P-448 dependent enzyme activities were measured at the age of 20 weeks. Phenobarbital had positive imprint effect on aminopyrine N-demethylase activity in female and on aniline hydroxylase activity in male rats. Flumecinol had no imprint effect. Chloramphenicol had a positive imprint on aniline hydroxylase activity in male rats. Sex differences in microsomal enzyme activities were not affected by the xenobiotics used.

Dominance of resistance to the alkylating agent 1,2:5,6-dianhydrogalactitol in P388 mouse lymphoma hybrid cells.

Cultured P388/S mouse lymphoma cells resistant to 5-bromodeoxyuridine (BUdR) and deficient in thymidine kinase (TK-) were fused with P388/DAG cells resistant to 1,2:5,6-dianhydrogalactitol (DAG), an anticancer alkylating agent, and to 6-thioguanine (6-TG) and deficient in hypoxanthine phosphoribosyl-transferase (HPRT-). Sensitivity to DAG in the hybrid line was very close to that in the P388/DAG line, which means that resistance to DAG was inherited in a quasi-dominant manner. Hybrid cells showed cross-resistance, similar to that of the DAG-resistant line, to two other hexitols, dibromodulcitol (DBD) and disuccinyldianhydrogalactitol (DisuDAG).

Development and some characteristics of a P388 leukemia strain resistant to 1, 2:5, 6-dianhydrogalactitol.

Repeated intraperitoneal treatment of standard P388 mouse leukemia with dianhydrogalactitol (DAG) resulted in the development of a P388/DAG experimental mouse tumor which was resistant to the drug. Resistance was stable without DAG treatment throughout 80 passages. P388/DAG shows cross-resistance to alkylating agents such as nitrogen-mustard, cyclophosphamide and diacetyl-DAG but not to selected antimetabolites and tubulin binders and exhibits reduced sensitivity to nitrosoureas. Resistance to DAG could not be overcome by the administration of maximally tolerated dose of DAG to tumor bearing mice. The resistant tumor is one chromosome short and shows a 13-fold increase of cells possessing a submetacentric marker chromosome.

Research related to the herbicide buvinol, especially for possible carcinogenicity.

The Budapest Chemical Works (Hungary) has conducted a study on a new herbicide called 'Buvinol', containing 2,4,5-trichlorophenoxyethanol (TCPE). In long-term carcinogenicity testing, the oral administration of the maximum tolerated dose of TCPE (70 mg/kg), containing 0.1 ppm 2,3,7,8-tetrachlorodibenzo-para-dioxin, increased the incidence of liver tumours in male mice, while smaller doses (1/10 and 1/100) did not. Dioxin in the dose range used (0.1--10 ppm) did not influence tumour frequency. Exposure of workers to TCPE during its production or use should be controlled and reduced.

Carcinogenic bioassay of the herbicide, 2,4,5-trichlorophenoxyethanol (TCPE) with different 2,3,7,8-tetrachlorodibenzo-p-dioxin (dioxin) content in Swiss mice.

The carcinogenic effect of a herbicide trichlorophenoxyethanol (TCPE) was investigated. The substance always contains 2,3,7,8-tetrachlorodibenzo-p-dioxin (dioxin) as a trace contaminant. Outbred Swiss-H/Riop mice were treated for 1 year with different doses of the various admixtures of the two compounds and those of dioxin alone to determine whether their carcinogenic effects are dose-dependent. Observation time after TCPE treatment was 1 and 2 years. The maximum tolerable dose of TCPE (70 mg/kg) with a dioxin concentration of 7.10(-6) mg/kg doubled the number of liver tumours as compared to the controls. The occurrence of liver tumours decreased at the administration of lower doses of the two compounds. No change in tumour frequency could be detected when the level of dioxin as a trace contaminant was raised, either (10 ppm). According to our preliminary results, dioxin has a more toxic than carcinogenic effect. The use of TCPE as a herbicide in accordance with the proper factory regulations and the consumption of products treated with it does not seem to bear a carcinogenic risk for the consumer.

Study of globular bodies found in hepatomas of Swiss mice.

In spontaneous hepatomas of Swiss mice a great number of eosinophilic globular bodies was observed without cirrhosis. Electron microscopy revealed their protein nature and origin from the rough endoplasmic reticulum cisternae.

[Globular corpuscles in hepatomas of Swiss mice]. / Swiss-egerek hepatomáiban talált globuláris testek vizsgálata

In hapatomas formed spontaneously without cirrhosis at Swiss mice numerous globular corpuscules of eosinophil character were found. These corpuscules as revealed by electron microscopy are formed in cyternas of the rough surfaced endoplasmatic reticulum and are of the nature of protein.