Ultrasound-guided percutaneous cryoneurolysis for management of acute sternal fracture pain.

Background: Establishing adequate analgesia for rib and sternal fractures remains a challenge due to the prolonged nature of the associated pain. Historically, cryoneurolysis has demonstrated beneficial in treating chronic pain, and the recent development of hand-held devices has allowed its functionality to expand into the management of acute pain. Case: We present a polytrauma patient with sternal and multiple rib fractures that underwent ultrasound-guided intercostal cryoneurolysis at bedside, resulting in significant analgesia lasting several weeks and improving mobilization. This is the first report of the utilization of cryoneurolysis to treat acute sternal fracture pain. Conclusion: The most common sternal fracture pattern is transverse which only requires treatment of four intercostal nerves, making cryoneurolysis feasible in trauma centers. This portable, minimally invasive, and low risk technique has the added benefits of reducing opioid requirements, decreasing length of hospital stay, and improving mobility in polytrauma patients.

Opinions on rehabilitation care of young adults with transversal upper limb reduction deficiency in their transition to adulthood.

PURPOSE: Young adults with transversal upper limb reduction deficiency experience limitations regarding education, employment and obtaining a driver's license. Contribution of rehabilitation care within these domains has been reported to be inadequate. This study evaluates the needs and suggestions of participants in rehabilitation care. METHODS: Two online focus groups with young adults and parents met during 4 consecutive days. Health care professionals joined a face-to-face focus group. Data analysis was based on framework analysis. RESULTS: The rehabilitation team was mainly consulted for problems with residual limb or for prostheses. Young adults and their parents were mostly unaware of resources regarding education, job selection or obtaining a driver's license. Professionals stated that these subjects were addressed during periodic appointments. Young adults didn't always attend these appointments due to limited perceived benefit. To improve rehabilitation care, participants suggested methods for providing relevant information, facilitating peer contact and offering dedicated training programs to practice work-related tasks, prepare for job interviews or enhance self-confidence. CONCLUSION: Periodic appointments do not fulfil needs of young adults with transversal upper limb reduction deficiency. To improve care, rehabilitation teams should offer age-relevant information, share peer stories, and create dedicated training programs.

Estimation of left ventricular pressure with the pump as "sensor" in patients with a continuous flow LVAD.

INTRODUCTION: In long-term ventricular support of patients with LVADs, left ventricular pressure (p(lv)) is relevant for indicating the unloading level of the heart. Monitoring of p(lv) over time might give more insight into the increase or decrease in native ventricular function. In this study, we aim to assess dynamic p(lv) noninvasively, using the LVAD as a pressure sensor. METHODS: Pressure head (dp(lvad)) was estimated from pump flow with a dynamic pump model (1). Estimated dp(lvad) and measured aortic pressure were used to calculate left ventricular pressure. Moreover, parameters dp/dtmax and mean, minimum, and maximum p(lv) were derived.The method was validated with a porcine ex vivo beating heart model by measurements conducted in 4 hearts supported with a Micromed DeBakey VAD and 3 hearts with a Heartmate II VAD. During each measurement, aortic and left ventricular pressure, pump flow, and pressure head were recorded for 30 s with a sampling frequency of 1 kHz. RESULTS: The estimation of left ventricular pressure appeared to be accurate for both pumps. The parameters mean and minimum pressure were estimated with high accuracy. The degree of accuracy of the estimated p(lv) was proportional to the degree of accuracy of the dynamic pump model. CONCLUSIONS: We proved that the LVAD model described in this paper can be used as a pressure indicator to determine LV pressure at any time based on noninvasive measurements of pump flow, aortic pressure, and the properties of the outlet graft.

Maternally-derived zinc transporters ZIP6 and ZIP10 drive the mammalian oocyte-to-egg transition.

Rapid cellular zinc influx regulates early mammalian development during the oocyte-to-egg transition through modulation of the meiotic cell cycle. Despite the physiological necessity of this zinc influx, the molecular mechanisms that govern such accumulation are unknown. Here we show that the fully grown mammalian oocyte does not employ a transcriptionally based mechanism of zinc regulation involving metal response element-binding transcription factor-1 (MTF-1), as demonstrated by a lack of MTF-1 responsiveness to environmental zinc manipulation. Instead, the mammalian oocyte controls zinc uptake through two maternally derived and cortically distributed zinc transporters, ZIP6 and ZIP10. Targeted disruption of these transporters using several approaches during meiotic maturation perturbs the intracellular zinc quota and results in a cell cycle arrest at a telophase I-like state. This arrest phenocopies established models of zinc insufficiency during the oocyte-to-egg transition, indicating the essential function of these maternally expressed transporters. Labile zinc localizes to punctate cytoplasmic structures in the human oocyte, and ZIP6 and ZIP10 are enriched in the cortex. Altogether, we demonstrate a mechanism of metal regulation required for female gamete development that may be evolutionarily conserved.

Pump flow estimation from pressure head and power uptake for the HeartAssist5, HeartMate II, and HeartWare VADs.

The use of long-term mechanical circulatory support (MCS) for heart failure by means of implanted continuous-flow left ventricular assist devices (cf-LVADs) will increase, either to enable recovery or to provide a destination therapy. The effectiveness and user-friendliness of MCS will depend on the development of near-physiologic control strategies for which accurate estimation of pump flow is essential. To provide means for the assessment of pump flow, this study presents pump models, estimating pump flow (Q(lvad)) from pump speed (n) and pressure difference across the LVAD (Δp(lvad)) or power uptake (P). The models are evaluated for the axial-flow LVADs HeartAssist5 (HA5) and HeartMate II (HMII), and for a centrifugal pump, the HeartWare (HW). For all three pumps, models estimating Q(lvad) from Δp(lvad) only is capable of describing pump behavior under static conditions. For the axial pumps, flow estimation from power uptake alone was not accurate. When assuming an increase in pump flow with increasing power uptake, low pump flows are overestimated in these pumps. Only for the HW, pump flow increased linearly with power uptake, resulting in a power-based pump model that estimates static pump flow accurately. The addition of pressure head measurements improved accuracy in the axial cf-LVAD estimation models.

Imaging and elemental mapping of biological specimens with a dual-EDS dedicated scanning transmission electron microscope.

A dedicated analytical scanning transmission electron microscope (STEM) with dual energy dispersive spectroscopy (EDS) detectors has been designed for complementary high performance imaging as well as high sensitivity elemental analysis and mapping of biological structures. The performance of this new design, based on a Hitachi HD-2300A model, was evaluated using a variety of biological specimens. With three imaging detectors, both the surface and internal structure of cells can be examined simultaneously. The whole-cell elemental mapping, especially of heavier metal species that have low cross-section for electron energy loss spectroscopy (EELS), can be faithfully obtained. Optimization of STEM imaging conditions is applied to thick sections as well as thin sections of biological cells under low-dose conditions at room and cryogenic temperatures. Such multimodal capabilities applied to soft/biological structures usher a new era for analytical studies in biological systems.

Retinoic acid induces blood-brain barrier development.

The blood-brain barrier (BBB) is crucial in the maintenance of a controlled environment within the brain to safeguard optimal neuronal function. The endothelial cells (ECs) of the BBB possess specific properties that restrict the entry of cells and metabolites into the CNS. The specialized BBB endothelial phenotype is induced during neurovascular development by surrounding cells of the CNS. However, the molecular differentiation of the BBB endothelium remains poorly understood. Retinoic acid (RA) plays a crucial role in the brain during embryogenesis. Because radial glial cells supply the brain with RA during the developmental cascade and associate closely with the developing vasculature, we hypothesize that RA is important for the induction of BBB properties in brain ECs. Analysis of human postmortem fetal brain tissue shows that the enzyme mainly responsible for RA synthesis, retinaldehyde dehydrogenase, is expressed by radial glial cells. In addition, the most important receptor for RA-driven signaling in the CNS, RA-receptor ß (RARß), is markedly expressed by the developing brain vasculature. Our findings have been further corroborated by in vitro experiments showing RA- and RARß-dependent induction of different aspects of the brain EC barrier. Finally, pharmacologic inhibition of RAR activation during the differentiation of the murine BBB resulted in the leakage of a fluorescent tracer as well as serum proteins into the developing brain and reduced the expression levels of important BBB determinants. Together, our results point to an important role for RA in the induction of the BBB during human and mouse development.

Development and evaluation of age-appropriate film-coated tablets of levamisole for paediatric use (2 - 18 years).

OBJECTIVES: To develop an oral solid dosage form of levamisole suitable for the paediatric population in terms of dose accuracy, palatability, stability and ease of administration. METHODS: Small undividable tablets (Ø5 - 8 mm) in four different strengths were manufactured to allow for flexible and accurate dosing. In vitro dissolution testing was used to determine drug release in different media. The bitter taste of levamisole was masked using a film-coat and assessed in healthy volunteers. Suitability and acceptability of the tablets were evaluated in 100 patients with nephrotic syndrome aged 2 - 18 years participating in a double blind, placebo-controlled, randomised trial. RESULTS: All tablet strengths showed good taste-masking characteristics and similar, pH independent, dissolution profiles. Successful taste masking was achieved without affecting the dissolution rate. In a total of 100 paediatric patients, more than 20,000 levamisole tablets were swallowed without any difficulties, choking or aspiration. CONCLUSION: The formulated tablets were found to be suitable for children aged 2 - 18 years and to provide good dose accuracy.

Brain endothelial barrier passage by monocytes is controlled by the endothelin system.

Homeostasis of the brain is dependent on the blood-brain barrier (BBB). This barrier tightly regulates the exchange of essential nutrients and limits the free flow of immune cells into the CNS. Perturbations of BBB function and the loss of its immune quiescence are hallmarks of a variety of brain diseases, including multiple sclerosis (MS), vascular dementia, and stroke. In particular, diapedesis of monocytes and subsequent trafficking of monocyte-derived macrophages into the brain are key mediators of demyelination and axonal damage in MS. Endothelin-1 (ET-1) is considered as a potent pro-inflammatory peptide and has been implicated in the development of cardiovascular diseases. Here, we studied the role of different components of the endothelin system, i.e., ET-1, its type B receptor (ET(B)) and endothelin-converting enzyme-1 (ECE-1) in monocyte diapedesis of a human brain endothelial cell barrier. Our pharmacological inhibitory and specific gene knockdown studies point to a regulatory function of these proteins in transendothelial passage of monocytes. Results from this study suggest that the endothelin system is a putative target within the brain for anti-inflammatory treatment in neurological diseases.

Object level HSI-LIDAR data fusion for automated detection of difficult targets.

Data fusion from disparate sensors significantly improves automated man-made target detection performance compared to that of just an individual sensor. In particular, it can solve hyperspectral imagery (HSI) detection problems pertaining to low-radiance man-made objects and objects in shadows. We present an algorithm that fuses HSI and LIDAR data for automated detection of man-made objects. LIDAR is used to define a set of potential targets based on physical dimensions, and HSI is then used to discriminate between man-made and natural objects. The discrimination technique is a novel HSI detection concept that uses an HSI detection score localization metric capable of distinguishing between wide-area score distributions inherent to natural objects and highly localized score distributions indicative of man-made targets. A typical man-made localization score was found to be around 0.5 compared to natural background typical localization scores being less than 0.1.

Alterations of A549 lung cell gene expression in response to biochemical toxins.

Health risks associated with the inhalation of potentially toxic materials have been a topic of great public concern. In vitro cellular analyses can provide mechanistic information on the molecular-level responses of lung-derived cell lines to a variety of these hazards. This understanding may be used to develop methods to reduce the damage from such toxins or to detect early stages of their effects. Here we describe an evaluation of the alterations in gene expression of an immortalized lung cell line (A549, human type II epithelia) to a variety of inhalation health hazards including etoposide, gliotoxin, streptolysin O, methyl methansesulfonate (MMS), and Triton X-100. The A549 cells display a dose-response relationship to each toxin with initial responses including alterations in metabolic activity, increases in membrane permeability, and initiation of response genes. In general, membrane-damaging agents (streptolysin O and Triton X-100) induce production of new ion channel proteins, structural proteins, and metabolic enzymes. Gliotoxin impacted the metabolic machinery, but also altered ion channels. Etoposide and MMS caused alterations in the cell cycle, induced DNA repair enzymes, and initiated apoptotic pathways, but MMS also induced immune response cascades. The mechanism of cell response to each toxin is supported by physiological analyses that indicated a fairly slow initiation of cell response to all compounds tested, except for Triton, which caused rapid decline in cell function due to solubilization of the cell membrane. However, Triton does induce production of a number of cell membrane-associated proteins and so its effects at low concentrations are likely translated throughout the cell. Together these results indicate a broader array of cellular responses to each of the test toxins than have previously been reported.

Ultrafast laser-induced phase transitions in amorphous GeSb films.

Time-resolved measurements of the spectral dielectric function reveal new information about ultrafast phase transitions induced by femtosecond laser pulses in Sb-rich amorphous GeSb films. The excitation generates a nonthermal phase within 200 fs. The dielectric function of this phase differs from that of the crystalline phase, contrary to previous suggestions of a disorder-to-order transition. The observed dielectric function is close to that of the liquid phase, indicating an ultrafast transition from the amorphous phase to a different disordered state.

Inverted double-gap isolation chamber for high-resolution calcium fluorimetry in skeletal muscle fibers.

Here we describe an improved inverted double-grease-gap isolation chamber that allows the formation of grease seals of high mechanical stability and high electrical resistance. We also provide a detailed description of the procedure used to mount the muscle fibers onto the apparatus. The new chamber permits the electrophysiological study of muscle fibers using an inverted microscope and high-resolution objectives, thus complying with the requirements of modern fluorescence confocal detection methods. The simplicity and reliability of the mounting procedure make this chamber preferable over other gap isolation chambers currently used for simultaneous electrophysiological and optical studies of calcium release. Experimental results obtained from amphibian muscle fibers are presented to illustrate the performance of the chamber when using global fluorescence detection, confocal spot detection, and laser confocal scanning imaging.

Supercharging accelerates T-tubule membrane potential changes in voltage clamped frog skeletal muscle fibers.

In voltage-clamp studies of single frog skeletal muscle fibers stained with the potentiometric indicator 1-(3-sulfonatopropyl)-4-[beta[2-(di-n-octylamino)-6-naphthyl] vinyl]pyridinium betaine (di-8 ANEPPS), fluorescence transients were recorded in response to both supercharging and step command pulses. Several illumination paradigms were utilized to study global and localized regions of the transverse tubule system (T-system). The rising phases of transients obtained from global illumination regions showed distinct accelerations when supercharging pulses were applied (95% of steady-state fluorescence achieved in 1.5 ms with supercharging pulses versus 14.6 ms with step pulses). When local transients were recorded at the edge of the muscle fiber, their kinetics resembled those of the applied waveform, but a similar relationship was not observed in transients from regions near the edge chosen to minimize the surface membrane contribution. We developed a model of the T-system capable of simulating membrane potential changes as a function of time and distance along the T-system cable and the associated fluorescence changes in regions corresponding to the experimental illumination strategies. A critical parameter was the access resistance term, for which values of 110-150 Omega.cm2 were adequate to fit the data. The results suggest that the primary mechanism through which supercharging pulses boost the kinetics of T-system voltage changes most likely involves their compensating the voltage attenuation across the access resistance at the mouth of the T-tubule.

Fast voltage gating of Ca2+ release in frog skeletal muscle revealed by supercharging pulses.

1. In single frog skeletal muscle fibres, we utilized supercharging voltage clamp command pulses to boost the rate of depolarization in the transverse tubular system (T-system) such that 95 % of steady-state potential is achieved in < 2 ms (as indicated by fluorescent potentiometric dye signals detected from a global illumination region). Signals detected near the edge of muscle fibres indicate that peripheral regions of the T-system are not significantly overcompensated under these conditions. 2. We explored the impact of accelerating T-system depolarization on voltage-dependent events of excitation-contraction (E-C) coupling by measuring charge movement currents (CMCs) and Ca2+ fluorescence transients in response to both supercharging and conventional step pulses. 3. When compared with CMCs elicited by step pulses, supercharging CMCs are larger, and their kinetics more closely resemble those of gating current records reported for ionic channels. Furthermore, they decay bi-exponentially (tau fast range, 1.3-1.8 ms; tau slow range, 7.3-11.9 ms), whereas step CMCs fall with a single exponential time course (tau range, 12.5-26.7 ms). 4. Similarly, supercharging produces a distinct acceleration in Ca2+ release transients, which show little evidence of the voltage-dependent onset latencies previously encountered using step pulses. 5. The use of this novel methodology in skeletal muscle unveils a previously undetected component of charge movement, the rapid, voltage-dependent recruitment of which may provide the basis for understanding the fast gating of physiological E-C coupling.

Kinetic properties of DM-nitrophen and calcium indicators: rapid transient response to flash photolysis.

We describe a high temporal resolution confocal spot microfluorimetry setup which makes possible the detection of fluorescence transients elicited by Ca2+ indicators in response to large (50-200 microM), short duration (< 100 ns), free [Ca2+] transients generated by laser flash photolysis of DM-nitrophen (DM-n; caged Ca2+). The equilibrium and kinetic properties of the commercially available indicators Fluo-3, Rhod-2, CalciumOrange-5N (COr-5N) and CalciumGreen-2 (CGr-2) were determined experimentally. The data reveal that COr-5N displays simple, fast response kinetics while, in contrast, Fluo-3, Rhod-2 and CGr-2 are characterized by significantly slower kinetic properties. These latter indicators may be unsuitable for tracking Ca2+ signaling events lasting only a few milliseconds. A model which accurately predicts the time course of fluorescence transients in response to rapid free [Ca2+] changes was developed. Experimental data and model predictions concur only when the association rate constant of DM-n is approximately 20 times faster than previously reported. This work establishes a quantitative theoretical framework for the study of fast Ca2+ signaling events and the use of flash photolysis in cells and model systems.

A gap isolation method to investigate electrical and mechanical properties of fully contracting skeletal muscle fibers.

We describe here a single-gap isolation method that allows the simultaneous measurement of electrical activity and tension output from fully contracting segments of frog skeletal muscle fibers. By using single pulses and pulse trains of varying frequency (5-100 Hz), records obtained for both electrical and mechanical fiber response demonstrate that the physiological properties of the fiber segments have been preserved. Action potentials could be recorded free of movement artifacts, even while segments were in fused tetani and developing maximum tensions of more than 600 kN/m2. Single current pulses evoked action potentials that averaged 144 +/- 16 mV (mean +/- SD, n = 8) in amplitude and twitches that averaged 285 +/- 66 kN/m2 and 55 +/- 5 ms (mean +/- SD, n = 20) in magnitude and time to peak, respectively. Trains of action potentials elicited patterns of tension development that exhibited summation, unfused tetani, and fused tetani in a frequency-dependent manner. The AC and DC electrical properties of the single grease gap were modeled with a simple Thévenin equivalent circuit, which satisfactorily predicted the experimental results. Our methodology is easily implemented and potentially applicable to any muscle preparation in which fiber segments with an intact end attached to a piece of tendon can be dissected.