Altered GABA and somatostatin modulation of proprioceptive feedback after spinal cord injury in lamprey

While various changes occur after spinal cord lesions, their influence on functional recovery is generally unclear. We have shown changes in proprioceptor and locomotor network properties below lesion sites in the lamprey spinal cord. The proprioceptive system offers a particularly tractable model for analyzing these changes. Here, we have sought evidence for changes in neuromodulatory effects below lesion sites by comparing the effects of gamma-aminobutyric acid (GABA) and somatostatin, both of which are located around the edge cells, on proprioceptive responses in lesioned and unlesioned spinal cords. Exogenously applied GABA significantly reduced or abolished bending-evoked responses in unlesioned animals. In lesioned animals bending-evoked responses were stronger and certain of the effects of exogenously applied GABA were reduced. However, blocking endogenous GABA with bicuculline significantly potentiated responses in lesioned but not unlesioned animals. This suggested that the potentiated responses in lesioned animals were nevertheless associated with stronger tonic GABAergic inhibition. There were significant differences in these effects when lesioned animals were separated on the basis of their degree of recovery: notably, bicuculline only potentiated responses in animals that recovered good locomotor function, suggesting a need for raised endogenous GABA levels. Somatostatin alone did not affect edge cell responses in lesioned or unlesioned animals, but in lesioned animals it reduced and thus further weakened the inhibitory effects of GABA. There are thus multiple changes in sensory modulation in the lesioned spinal cord, and differences in these effects may influence the degree of recovery.

Profiling of sputum inflammatory mediators in asthma and chronic obstructive pulmonary disease

Background

Asthma and chronic obstructive pulmonary disease (COPD) display features of overlap in airway physiology and airway inflammation. Whether inflammatory phenotypes in airway disease describe similar mediator expression is unknown.

Objectives

To explore the relationship of airway inflammation and cytokine and chemokine expression in asthma and COPD.

Methods

Subjects with asthma and COPD (n = 54 and n = 49) were studied. Clinical characteristics and sputum were collected at entry into the study. A 2-step sputum processing method was performed for supernatant and cytospin preparation. Meso Scale Discovery and Luminex platforms were used to measure cytokines, chemokines and matrix metalloproteinase levels.

Results

Analytes sensitive to dithiothreitol (DTT) that had increased recovery in the 2-step sputum process were IL-1β, 4, 5, 10, 13, IFN-γ, TNFRI, GM-CSF, CCL2, 3, 4, 5, 13 and 17. There was a differential expression in IL-8, TNFRI and TNFRII between asthma and COPD [mean fold difference (95% CI): IL-8, 2.6 (1.3–5.4), p = 0.01; TNFRI, 2.1 (1.3–5.4), p = 0.03; TNFRII, 2.6 (1.2–5.6), p = 0.02]. In neutrophilic and eosinophilic airway inflammation, TNFα, TNFRI, TNFRII, IL-6, IL-8 and IL-5 could differentiate between these phenotypes. However, these phenotypes were unrelated to the diagnosis of asthma or COPD.

Conclusion

Recovery of sputum mediators sensitive to DTT can be improved using the described sputum processing technique. Within airway inflammatory sub-phenotypes there is a differential pattern of mediator expression that is independent of disease. Whether these inflammatory phenotypes in asthma and COPD confer distinct pathogeneses, therapeutic responses and clinical phenotypes needs to be further evaluated.

High-resolution diffusion-weighted imaging of neck lymph nodes using 2D-single-shot interleaved multiple inner volume imaging diffusion-weighted echo-planar imaging at 3T

BACKGROUND AND PURPOSE

2D-ss-IMIV-DWEPI is an ss-DWEPI with greatly reduced geometric distortion. The purposes of this paper are to 1) evaluate of the utility of 2D-ss-IMIV-DWEPI for high-resolution neck LN imaging; 2) determine whether 2D-ss-IMIV-DWEPI can depict normal LN hilum; and 3) evaluate whether the inclusion of LN hilum within ROIs affects the measured LN ADC.

MATERIALS AND METHODS

HR-DWI was acquired with 1-mm² in-plane resolution and 2-mm section thickness by using 2D-ss-IMIV-DWEPI. In total, 58 LNs from 18 subjects were evaluated. The ADC map was calculated by using DWI with b = 10 and 300 s/mm². In those LNs where the LN hilum could be recognized, the LN ADC was measured with and without inclusion of the hilum, and the mean difference of the resulting ADC values was determined.

RESULTS

The hilar structure was identified by DWI in 15 LNs. The ADC of the hilum was 1.981 ± 0.331 × 10⁻³ mm²/s. In these 15 LNs, the ADC value excluding hilar structure was significantly lower than the ADC value including hilar structure (0.983 ± 0.169 versus 1.206 ± 0.244 × 10⁻³ mm²/s; P < .0001). The mean ADC in a total of 58 LNs excluding the hilar structure was significantly lower than the value obtained including the hilar structure (1.034 ± 0.183 versus 1.095 ± 0.213 × 10⁻³ mm²/s; P = .0002).

CONCLUSIONS

HR-DWI of neck LNs obtained by using 2D-ss-IMIV-DWEPI could identify the hilar structure. The ADC of normal neck LNs seemed significantly different when the hilum was included. The results suggest that HR-DWI may be helpful to aid selection of proper ROIs within LNs for accurate and reliable ADC measurements.

Determination of gap symmetry from angle-dependent H(c2) measurements on CeCu₂Si₂

The tetragonal heavy-fermion compound CeCu₂Si₂ exhibits a superconducting ground state (S type, T(c) = 0.67 K) close to a magnetic instability. Here, we present angle-resolved resistivity measurements of the upper critical field H(c2). In-plane rotation of S-type CeCu₂Si₂ single crystals reveals a fourfold oscillation of H(c2). An extended weak-coupling BCS model for a d-wave symmetry including strong Pauli-limiting effects confirms the aforementioned angular dependence and points towards d(xy) symmetry of the order parameter.

On-line monitoring of nitrogenase activity in cyanobacteria by sensitive laser photoacoustic detection of ethylene

A new and extremely sensitive method for measuring nitrogenase activity through acetylene reduction is presented. Ethylene produced by nitrogenase-mediated reduction of acetylene is detected by using laser photoacoustics (LPA). This method possesses a detection limit making it 3 orders of magnitude more sensitive than traditional gas chromatographic analysis. Photoacoustic detection is based on the strong and unique absorption pattern of ethylene in the CO(inf2) laser wavelength region (9 to 11 (mu)m). The high sensitivity allowed on-line monitoring of nitrogenase activity in a culture of the heterocystous cyanobacterium Nodularia spumigena, which was isolated from a water bloom in the Baltic Sea. This setup makes it unnecessary to take subsamples from the culture and avoids long incubations in sealed vials. The fast response of the LPA technique allows measurement of real-time dynamic changes of nitrogenase activity. The method was used to analyze in vivo saturation of nitrogenase by acetylene in N. spumigena. It is demonstrated that 20% acetylene does not saturate nitrogenase and that the degree of saturation depends on light intensity. With concentrations of acetylene as low as 2.5% it is possible to assess the degree of saturation and to extrapolate to total nitrogenase activity. In N. spumigena nitrogenase activity becomes independent of light intensity above 20 to 80 (mu)mol of photons m(sup-2) s(sup-1) at 20% O(inf2).

Lesioning alters functional properties in isolated spinal cord hemisegmental networks

Hemisegmental networks produced by longitudinal lesions of the spinal cord midline are able to generate rhythmic bursting activity. This has led to the suggestion that hemisegmental networks can independently burst in the intact spinal cord. Previous analyses in the lamprey spinal cord failed to show hemisegmental bursting in NMDA. This was subsequently attributed to the failure to wait sufficient time for NMDA-evoked hemisegmental activity to recover after being abolished by the lesion, which can take tens of minutes to hours. The reason for this delay in the onset of NMDA-evoked activity was not previously addressed. We have investigated it here by examining two hypotheses: that hemisegmental networks intrinsically burst under normal conditions but that NMDA-evoked bursting was temporarily silenced by lesion-induced transmitter release; or that lesioning altered functional properties in the hemisegment that subsequently led to the development of bursting. We found no evidence to support transmitter-induced silencing of ongoing NMDA-evoked hemisegmental activity, but did find evidence for significant changes in the cellular and synaptic properties of motor neurons and premotor excitatory interneurons in lesioned hemisegmental networks. These results thus suggest that there are lesion-induced changes in functional properties in hemisegmental networks. As the interpretation of lesion studies rests on the assumption that the functional properties of hemisegmental components are not altered, further work is needed before conclusions can be made about the function of the intact system.

A randomised controlled trial to compare postoperative pain in children undergoing tonsillectomy using cold steel dissection with bipolar haemostasis versus coblation technique

OBJECTIVE

To measure postoperative pain levels in children undergoing tonsillectomy, by two different techniques, cold steel dissection and coblator dissection. The hypothesis - that coblator dissection may be associated with less postoperative pain.

DESIGN

Prospective, randomised, double blind trial.

SETTING

Single centre, secondary care Children's Hospital.

PARTICIPANTS

Children aged between 4 and 16 years, undergoing tonsillectomy, or adeno-tonsillectomy.

EXCLUSION CRITERIA

children already taking regular analgesia and those who experienced postoperative bleeding. Seventy-nine children were recruited, nine were excluded.

MAIN OUTCOME MEASURES

We compared analgesia requirements during the first 10 days, and also the return to normal eating and drinking. These were assessed, using a validated pain scale. All analgesic administration in hospital and at home was compared. The return to normal eating & drinking patterns, was also compared.

RESULTS

Whilst in the 24 h postoperatively there was no significant difference in the pain scores between the two groups, the coblator group required less potent analgesia. No statistical difference was identified between the two groups following discharge, except on the sixth postoperative day, when the coblator group had lower pain scores. This may represent chance, rather than a clear difference.

CONCLUSION

The findings do not confirm the hypothesis that tonsillectomy undertaken in children, with the coblator device, is associated with lower levels of postoperative pain, but do indicate that less analgesia is required by the coblator patients in the first 12 h postoperatively.

Possible phase-sensitive tests of pairing symmetry in pnictide superconductors

The discovery of the new class of pnictide superconductors has engendered a controversy about their pairing symmetry, with proposals ranging from an extended s wave or "s_{+/-}" symmetry to nodal or nodeless d-wave symmetry to still more exotic order parameters such as p wave. In this Letter, building on the earlier, similar work performed for the cuprates, we propose several phase-sensitive Josephson interferometry experiments, each of which may allow resolution of the issue.

Granulocyte-macrophage colony-stimulating factor expression in induced sputum and bronchial mucosa in asthma and COPD

Background:

Granulocyte–macrophage colony-stimulating factor (GM-CSF) has been implicated as an important mediator in the pathogenesis of asthma and chronic obstructive pulmonary disease (COPD). However, the expression of GM-CSF and its receptor in airway samples in asthma and COPD across disease severity needs to be further defined.

Methods:

Sputum GM-CSF was measured in 18 control subjects, 45 subjects with asthma and 47 subjects with COPD. Enumeration of GM-CSF+ cells in the bronchial submucosa and airway smooth muscle bundle was performed in 29 control subjects, 36 subjects with asthma and 10 subjects with COPD.

Results:

The proportion of subjects with measurable GM-CSF in the sputum was raised in those with moderate (7/14) and severe (11/18) asthma, and in those with COPD GOLD (Global Initiative for Chronic Obstructive Lung Disease) stage II (7/16), III (8/17) and IV (7/14) compared with controls (1/18) and those with mild asthma (0/13); p = 0.001. The sputum GM-CSF concentration was correlated with the sputum eosinophilia in subjects with moderate to severe asthma (r_s = 0.41; p = 0.018). The median (interquartile range) GM-CSF+ and GM-CSFR+ cells/mm² of submucosa was increased in severe asthma (1.4 (3.0) and 2.1 (8.4)) compared with those with mild to moderate asthma (0 (2.5) and 1.1 (5)) and healthy controls (0 (0.5) and 0 (1.6)), (p = 0.004 and p = 0.02, respectively).

Conclusions:

The findings support a potential role for GM-CSF in asthma and COPD and suggest that overexpression of GM-CSF in sputum and the bronchial mucosa is a particular feature of severe asthma.