Changes in midbrain pain receptor expression, gait and behavioral sensitivity in a rat model of radiculopathy.

Intervertebral disc herniation may contribute to inflammatory processes that associate with radicular pain and motor deficits. Molecular changes at the affected dorsal root ganglion (DRG), spinal cord, and even midbrain, have been documented in rat models of radiculopathy or nerve injury. The objective of this study was to evaluate gait and the expression of key pain receptors in the midbrain in a rodent model of radiculopathy. Radiculopathy was induced by harvesting tail nucleus pulposus (NP) and placing upon the right L5 DRG in rats (NP-treated, n=12). Tail NP was discarded in sham-operated animals (n=12). Mechanical allodynia, weight-bearing, and gait were evaluated in all animals over time. At 1 and 4 weeks after surgery, astrocyte and microglial activation was tested in DRG sections. Midbrain sections were similarly evaluated for immunoreactivity to serotonin (5HT(2B)), mu-opioid (µ-OR), and metabotropic glutamate (mGluR4 and 5) receptor antibodies. NP-treated animals placed less weight on the affected limb 1 week after surgery and experienced mechanical hypersensitivity over the duration of the study. Astroctye activation was observed at DRGs only at 4 weeks after surgery. Findings for pain receptors in the midbrain of NP-treated rats included an increased expression of 5HT(2B) at 1, but not 4 weeks; increased expression of µ-OR and mGluR5 at 1 and 4 weeks (periaqueductal gray region only); and no changes in expression of mGluR4 at any point in this study. These observations provide support for the hypothesis that the midbrain responds to DRG injury with a transient change in receptors regulating pain responses.

Increasing arousal enhances inhibitory control in calm but not excitable dogs

© 2015, Springer-Verlag Berlin Heidelberg.The emotional-reactivity hypothesis proposes that problem-solving abilities can be constrained by temperament, within and across species. One way to test this hypothesis is with the predictions of the Yerkes–Dodson law. The law posits that arousal level, a component of temperament, affects problem solving in an inverted U-shaped relationship: Optimal performance is reached at intermediate levels of arousal and impeded by high and low levels. Thus, a powerful test of the emotional-reactivity hypothesis is to compare cognitive performance in dog populations that have been bred and trained based in part on their arousal levels. We therefore compared a group of pet dogs to a group of assistance dogs bred and trained for low arousal (N = 106) on a task of inhibitory control involving a detour response. Consistent with the Yerkes–Dodson law, assistance dogs, which began the test with lower levels of baseline arousal, showed improvements when arousal was artificially increased. In contrast, pet dogs, which began the test with higher levels of baseline arousal, were negatively affected when their arousal was increased. Furthermore, the dogs’ baseline levels of arousal, as measured in their rate of tail wagging, differed by population in the expected directions. Low-arousal assistance dogs showed the most inhibition in a detour task when humans eagerly encouraged them, while more highly aroused pet dogs performed worst on the same task with strong encouragement. Our findings support the hypothesis that selection on temperament can have important implications for cognitive performance.

A whole-cell and single-channel study of the voltage-dependent outward potassium current in avian hepatocytes.

Voltage-dependent membrane currents were studied in dissociated hepatocytes from chick, using the patch-clamp technique. All cells had voltage-dependent outward K+ currents; in 10% of the cells, a fast, transient, tetrodotoxin-sensitive Na+ current was identified. None of the cells had voltage-dependent inward Ca2+ currents. The K+ current activated at a membrane potential of about -10 mV, had a sigmoidal time course, and did not inactivate in 500 ms. The maximum outward conductance was 6.6 +/- 2.4 nS in 18 cells. The reversal potential, estimated from tail current measurements, shifted by 50 mV per 10-fold increase in the external K+ concentration. The current traces were fitted by n2 kinetics with voltage-dependent time constants. Omitting Ca2+ from the external bath or buffering the internal Ca2+ with EGTA did not alter the outward current, which shows that Ca2+-activated K+ currents were not present. 1-5 mM 4-aminopyridine, 0.5-2 mM BaCl2, and 0.1-1 mM CdCl2 reversibly inhibited the current. The block caused by Ba was voltage dependent. Single-channel currents were recorded in cell-attached and outside-out patches. The mean unitary conductance was 7 pS, and the channels displayed bursting kinetics. Thus, avian hepatocytes have a single type of K+ channel belonging to the delayed rectifier class of K+ channels.

Violence Exposure and Welfare over Time: Evidence from the Burundi Civil War

We investigate the relationship between exposure to conflict and poverty dynamics over time, using original three-waves panel data for Burundi which tracked individuals and reported local-level violence exposure from 1998 to 2012. Firstly, the data reveal that headcount poverty has not changed since 1998 while we observe multiple transitions into and out of poverty. Moreover, households exposed to the war exhibit a lower level of welfare than non-exposed households, with the difference between the two groups predicted to remain significant at least until 2017, i.e. twelve years after the conflict termination. The correlation between violence exposure and deprivation over time is confirmed in a household-level panel setting. Secondly, our empirical investigation shows how violence exposure over different time spans interacts with households' subsequent welfare. Our analysis of the determinants of households' likelihood to switch poverty status (i.e. to fall into poverty or escape poverty) combined with quantile regressions suggest that, (i) exposure during the first phase of the conflict has affected the entire distribution, and (ii) exposure during the second phase of the conflict has mostly affected the upper tail of the distribution: initially non-poor households have a higher propensity to fall into poverty while initially poor households see their propensity to pull through only slightly decrease with recent exposure to violence. Although not directly testable with the data at hand, these results are consistent with the changing nature of violence in the course of the Burundi civil war, from relatively more labour-destructive to relatively more capital-destructive.

Analysis of species hyper-diversity in the tropical rain forests of Indonesia: the problem of non-observance

The main interest in the assessment of forest species diversity for conservation purposes is in the rare species. The main problem in the tropical rain forests is that most of the species are rare. Assessment of species diversity in the tropical rain forests is therefore often concerned with estimating that which is not observed in recorded samples. Statistical methodology is therefore required to try to estimate the truncated tail of the species frequency distribution, or to estimate the asymptote of species/diversity-area curves. A Horvitz-Thompson estimator of the number of unobserved (“virtual”) species in each species intensity class is proposed. The approach allows a definition of an extended definition of diversity, ( or generalised Renyi entropy). The paper presents a case study from data collected in Jambi, Sumatra, and the “extended diversity measure” is used on the species data.

HAMSTER OVIDUCTIN ENHANCES TYROSINE PHOSPHORYLATION OF SPERM PROTEINS DURING CAPACITATION

Capacitation is essential for fertilization of ovulated oocytes. Capacitation is correlated with activation of a signal transduction pathway leading to protein tyrosine phosphorylation, an essential prerequisite for fertilization. Oviductin has been shown to bind to the acrosomal cap and the equatorial segment region of the sperm head. In light of findings reported in previous studies, we hypothesized that estrus stage-specific oviductin (EOV) enhances tyrosine phosphorylation. Immunofluorescent detection by light and confocal microscopy and immunogold labeling by electron microscopy and surface replica techniques were used to localize tyrosine phosphorylated proteins to the equatorial segment region and midpiece after incubation in medium in the presence or absence of EOV. In the presence of EOV, an increase in tyrosine phosphorylation in the equatorial segment region was observed as early as 5 minutes after incubation. On prolonging incubation in medium containing EOV immunostaining further increased, indicative of increased levels of tyrosine phosphorylation of sperm proteins as capacitation proceeds. Regardless of the presence or absence of EOV, phosphotyrosine expression was observed along the tail, specifically at the midpiece. However, this reactivity was enhanced in the presence of EOV. Western blot analysis of NP-40 extractable and non-extractable sperm proteins confirmed these observations. NP-40 extractable sperm proteins (25, 37, 44kDa) and non-extractable sperm proteins (70, 83, 90kDa) showed increased intensity when sperm were capacitated in the presence of EOV after 5-, 60-, 120- and 180-minutes of capacitation. Mass spectrophotometric analysis identified enolase, ATP-specific succinyl CoA, succinate CoA ligase, zona pellucida binding protein, heat shock protein 90, aconitase and hexokinase as proteins that undergo enhancement in tyrosine phosphorylation in the presence of EOV. The proteins identified are known to be involved in specific functions including cellular metabolism, molecular chaperoning and normal sperm development. In summary, the present investigation has provided new evidence showing that sperm capacitated in vitro in the presence of EOV display an enhanced expression of tyrosine phosphorylation compared to sperm incubated in capacitating medium alone. These results indicate that inclusion of oviductin in media used for in vitro fertilization (IVF) may improve success rates of IVF by enhancing the signaling pathways involved in sperm capacitation.

Particle Image Velocimetry Investigation of a finite amplitude pressure wave

Particle image velocimetry is used to study the motion of gas within a duct subject to the passage of a finite amplitude pressure wave. The wave is representative of the pressure waves found in the exhaust systems of internal combustion engines. Gas particles are accelerated from stationary to 150 m/s and then back to stationary in 8 ms. It is demonstrated that gas particles at the head of the wave travel at the same velocity across the duct cross section at a given point in time. Towards the tail of the wave viscous effects are plainly evident causing the flow profile to tend towards parabolic. However, the instantaneous mean particle velocity across the section is shown to match well with the velocity calculated from a corresponding measured pressure history using 1D gas dynamic theory. The measured pressure history at a point in the duct was acquired using a high speed pressure transducer of the type typically used for engine research in intake and exhaust systems. It is demonstrated that these are unable to follow the rapid changes in pressure accurately and that they are prone to resonate under certain circumstances.

Passive Control of Plume Interference on Slender Axisymmetric Bodies

The physics of the plume-induced shock and separation, particularly at high plume to exit pressure ratios with and without shock-turbulent boundary-layer control methods, were studied using computational techniques. Mass-averaged Navier-Stokes equations with a two-equation turbulence model were solved by using a fully implicit finite volume scheme and time.marching algorithm. The control methodologies for shock interactions included a porous tail and a porous extension attached at the nozzle exit or trailing edge. The porous tail produced a weaker shock and fixed the shock position on the control surface. The effect of the porous extension on shock interactions was mainly to restrain the plume from strongly underexpanding during a change in flight conditions. These techniques could give an additional dimension to the design and control of supersonic missiles.

A FUNCTIONAL, COMPARATIVE AND CLINICAL ANALYSIS OF SPERM-BORNE OOCYTE ACTIVATING FACTOR, PAWP

Successful fertilization depends upon the activation of metaphase II arrested oocytes by sperm-borne oocyte activating factor (SOAF). Failure of oocyte activation is considered as the cause of treatment failure in a proportion of infertile couples. SOAF induces the release of intracellular calcium in oocyte which leads to meiotic resumption and pronuclear formation. Calcium release is either in the form of single calcium transient in echinoderm and amphibian oocytes or several calcium oscillations in ascidian and mammalian oocytes. Although the SOAF attributes are established, it is not clear which sperm protein(s) play such role. Sperm postacrosomal WW binding protein (PAWP) satisfies a developmental criteria set for a candidate SOAF. This study shows that recombinant human PAWP protein or its transcript acts upstream of calcium release and fully activates the amphibian and mammalian oocytes. Interference trials provided evidence for the first time that PAWP mediates sperm-induced intracellular calcium release through a PPXY/WWI domain module in Xenopus, mouse and human oocytes. Clinical applications of PAWP were further investigated by prospective study on the sperm samples from patients undergoing intracytoplasmic sperm injection (ICSI). PAWP expression level, analyzed by flow cytometry, was correlated to ICSI success rate and embryonic development. This study also explored the developmental expression of the other SOAF candidate, PLCζ in male reproductive system and its function during fertilization. Our findings showed for the first time that PLCζ most likely binds to the sperm head surface during epididymal passage and is expressed in epididymis. We demonstrated that PLCζ is also compartmentalized early in spermiogenesis and thus could play an important role during spermiogenesis. Detailed analysis of in vitro fertilization revealed that PLCζ disappears from sperm head during acrosome reaction and is not detectable during sperm incorporation into the oocyte cytoplasm. In conclusion, this dissertation provides evidence for the essential non-redundant role of sperm PAWP in amphibian and mammalian fertilization; recommends PAWP as a biomarker for prediction of ICSI outcomes in infertile couples; and proposes that sperm PLCζ may have functions other than inducing oocyte activation during fertilization.

Fas and DNA double stranded breaks in human ejaculated sperm

Objective: to determine the incidence of Fas positivity and DNA double stranded breaks (DSB) as indicators of early and late stage apoptosis in ejaculated sperm. Design: Fas positivity was assessed by flow cytometry and DSB by neutral Comet assay Setting: Andrology Laboratory, Royal Maternity Hospita, Belfast Northern Ireland, UK. Patients: 45 infertile men undergoing infertility investigations and 10 fertile men undergoing vasectomies Main Outcome measures: Perecentage Fas positive cells, percentage DNA fragmentation, olive tail moments Results: The apoptotic marker Fas was detected in ejaculated sperm, with a higher incidence of Fas positivity in teratozoospermic and asthenozoospermic than in normozoospermic semen. No Fas positivity was observed in fertile mens’ sperm. DSB were greater in infertile than in fertile mens’ sperm and also greater in sperm in semen than in sperm prepared for assisted conception. There was an inverse relationship between DSB and both sperm concentration and motility. There was no relationship between Fas positivity and DNA damage. Conclusion: Fas was expressed in sperm of infertile men. In contrast, DNA fragmentation was observed in all sperm of fertile and infertile men and correlated with inadequate concentration and motility, which suggests that sperm DSB are ubiquitous and are not solely associated with apoptosis.

Ca(2+)-activated Cl(-) current in sheep lymphatic smooth muscle.

Freshly dispersed sheep mesenteric lymphatic smooth muscle cells were studied at 37 degrees C using the perforated patch-clamp technique with Cs(+)- and K(+)-filled pipettes. Depolarizing steps evoked currents that consisted of L-type Ca(2+) [I(Ca(L))] current and a slowly developing current. The slow current reversed at 1 +/- 1.5 mV with symmetrical Cl(-) concentrations compared with 23.2 +/- 1.2 mV (n = 5) and -34.3 +/- 3.5 mV (n = 4) when external Cl(-) was substituted with either glutamate (86 mM) or I(-) (125 mM). Nifedipine (1 microM) blocked and BAY K 8644 enhanced I(Ca(L)), the slow-developing sustained current, and the tail current. The Cl(-) channel blocker anthracene-9-carboxylic acid (9-AC) reduced only the slowly developing inward and tail currents. Application of caffeine (10 mM) to voltage-clamped cells evoked currents that reversed close to the Cl(-) equilibrium potential and were sensitive to 9-AC. Small spontaneous transient depolarizations and larger action potentials were observed in current clamp, and these were blocked by 9-AC. Evoked action potentials were triphasic and had a prominent plateau phase that was selectively blocked by 9-AC. Similarly, fluid output was reduced by 9-AC in doubly cannulated segments of spontaneously pumping sheep lymphatics, suggesting that the Ca(2+)-activated Cl(-) current plays an important role in the electrical activity underlying spontaneous activity in this tissue. PMID: 11029279 [PubMed - indexed for MEDLINE]

Ca2+ current and Ca(2+)-activated chloride current in isolated smooth muscle cells of the sheep urethra.

1. Isolated sheep urethral cells were studied using the perforated patch clamp technique (T = 37 degrees C). Depolarizing steps ranging from -40 to -10 mV evoked an inward current that peaked within 10 ms and a slower inward current. Stepping back to the holding potential of -80 mV evoked large inward tail currents. All three currents were abolished by nifedipine (1 microM). Substitution of external Ca2+ with Ba2+ resulted in potentiation of the fast inward current and blockade of the slow current and tails. 2. Changing the chloride equilibrium potential (ECl) from 0 to +27 mV shifted the reversal potential of the tail currents from 1 +/- 1 to 27 +/- 1 mV (number of cells, n = 5). Chloride channel blockers, niflumic acid (10 microM) and anthracene-9-carboxylic acid (9AC, 1 mM), reduced the slow current and tails suggesting that these were Ca(2+)-activated Cl- currents, ICl(Ca). 4. Caffeine (10 mM) induced currents that reversed at ECl and were blocked by niflumic acid (10 microM). 5. In current clamp mode, some cells developed spontaneous transient depolarizations (STDs) and action potentials. Short exposure to nifedipine blocked the action potentials and unmasked STDs. In contrast, 9AC and niflumic acid reduced the amplitude of the STDs and blocked the action potentials. 6. In conclusion, these cells have both L-type ICa and ICl(Ca). The former appears to be responsible for the upstroke of the action potential, while the latter may act as a pacemaker current.

A study of the Type II-P supernova 2003gd in M74

We present photometric and spectroscopic data of the Type II-P supernova (SN II-P) 2003gd, which was discovered in M74 close to the end of its plateau phase. SN 2003gd is the first Type II supernova ( SN) to have a directly confirmed red supergiant ( RSG) progenitor. We compare SN 2003gd to SN 1999 em, a similar SN II-P, and estimate an explosion date of 2003 March 18. We determine a reddening towards the SN of E(B-V) = 0.14 +/- 0.06, using three different methods. We also calculate three new distances to M74 of 9.6 +/- 2.8, 7.7 +/- 1.7 and 9.6 +/- 2.2 Mpc. The former was estimated using the standard candle method (SCM), for Type II supernovae (SNe II), and the latter two using the brightest supergiants method (BSM). When combined with existing kinematic and BSM distance estimates, we derive a mean value of 9.3 +/- 1.8 Mpc. SN 2003gd was found to have a lower tail luminosity compared with other normal Type II-P supernovae ( SNe II-P) bringing into question the nature of this SN. We present a discussion concluding that this is a normal SN II-P, which is consistent with the observed progenitor mass of 8(-2)(+4) M-circle dot.

Time signatures of impulsively generated coronal fast wave trains

Impulsively generated short-period fast magneto-acoustic wave trains, guided by solar and stellar coronal loops, are numerically modelled. In the developed stage of the evolution, the wave trains have a characteristic quasi-periodic signature. The quasi-periodicity results from the geometrical dispersion of the guided fast modes, determined by the transverse profile of the loop. A typical feature of the signature is a tadpole wavelet Spectrum: a narrow-spectrum tail precedes a broad-band head. The instantaneous period of the oscillations in the wave train decreases gradually with time. The period and the spectral amplitude evolution are shown to be determined by the steepness of the transverse density profile and the density contrast ratio in the loop. The propagating wave trains recently discovered with the Solar Eclipse Coronal Imaging System (SECIS) instrument are noted to have similar wavelet spectral features, which strengthens the interpretation of SECIS results as guided fast wave trains.

Surface plasmon polariton propagation length: A direct comparison using photon scanning tunneling microscopy and attenuated total reflection

The propagation of surface plasmon polaritons (SPP's) is studied using a photon scanning tunneling microscope (PSTM) and conventional attenuated total reflection (ATR). The PSTM experiment uses localized (focused beam) launching or SPP's at a wavelength of 632.8 nm. Propagation of the SPP is observed as an exponentially decaying tail beyond the launch site acid the 1/e propagation length is measured directly for a series of Ag films of different thicknesses. The ATR measurements are used to characterize the thin film optical and thickness parameters, revealing, notably, the presence of a contaminating adlayer of Ag2S of typical dielectric function, 8.7 + i2.7, and thickness 1-2 nm. Values of the SPP propagation length, based on the ATR- derived film parameters used in the four-media implicit SPP dispersion relation, show very good agreement with those based on the PSTM images for the case of undercoupled or optimally coupled SPP modes. The observed propagation lengths are quantitatively analyzed taking explicit account of additional intrinsic damping due to the growth of the Ag2S layer and of reradiation of the SPP back into the prism outside the launch site. Finally, the PSTM images show excellent SPP beam confinement in the original propagation direction.