Nicotine has a Direct Effect on Brainstem Startle-Mediating Neurons

Individuals with schizophrenia have impairments in prepulse inhibition of startle (PPI) which correlates with cognitive deficits. Nicotine improves the performance of patients and healthy individuals with PPI deficits on PPI tests. We hypothesized that nicotine directly affect startle-mediating neurons of the caudal pontine recticular nucleus (PnC) of the brainstem using electrophysiological recordings. The data revealed that nicotine (10 pM) increases leak current amplitude, reduces membrane resistance, and depolarizes the resting membrane potential. Nicotine had no significant effect on the EPSC amplitude for neither the trigeminal nor auditory stimulations. All effects were reversed only by a high dose (10 pM) of the a-j nAChR antagonist MLA and a low dose of TMPH (lOOnM; antagonizes all but the a7 nAChR). The effect of nicotine persisted in the presence of cadmium (100 pM), which blocks synaptic transmission. These results confirm the functional expression of nAChRs in the PnC and suggest a role of nAChRs in modulating startle responses directly in the brainstem

On determining the noon polar cap boundary from SuperDARN HF radar backscatter characteristics

International audiencePrevious work has shown that ionospheric HF radar backscatter in the noon sector can be used to locate the footprint of the magnetospheric cusp particle precipitation. This has enabled the radar data to be used as a proxy for the location of the polar cap boundary, and hence measure the flow of plasma across it to derive the reconnection electric field in the ionosphere. This work used only single radar data sets with a field of view limited to ~2 h of local time. In this case study using four of the SuperDARN radars, we examine the boundary determined over 6 h of magnetic local time around the noon sector and its relationship to the convection pattern. The variation with longitude of the latitude of the radar scatter with cusp characteristics shows a bay-like feature. It is shown that this feature is shaped by the variation with longitude of the poleward flow component of the ionospheric plasma and may be understood in terms of cusp ion time-of-flight effects. Using this interpretation, we derive the time-of-flight of the cusp ions and find that it is consistent with approximately 1 keV ions injected from a subsolar reconnection site. A method for deriving a more accurate estimate of the location of the open-closed field line boundary from HF radar data is described.Key words: Ionosphere (ionosphere?magnetosphere interactions; plasma convection) · Magnetospheric physics (magnetopause · cusp · and boundary layers

Generational perspective on asthma self-management in the Bangladeshi and Pakistani community in the United Kingdom: A qualitative study

BACKGROUND: Self‐management strategies improve asthma outcomes, although interventions for South Asian populations have been less effective than in White populations. Both self‐management and culture are dynamic, and factors such as acculturation and generation have not always been adequately reflected in existing cultural interventions. We aimed to explore the perspectives of Bangladeshi and Pakistani people in the United Kingdom, across multiple generations (first, second and third/fourth), on how they self‐manage their asthma, with a view to suggesting recommendations for cultural interventions. METHODS: We purposively recruited Bangladeshi and Pakistani participants, with an active diagnosis of asthma from healthcare settings. Semi‐structured interviews in the participants' choice of language (English, Sylheti, Standard Bengali or Urdu) were conducted, and data were analysed thematically. RESULTS: Twenty‐seven participants (13 Bangladeshi and 14 Pakistani) were interviewed. There were generational differences in self‐management, influenced by complex cultural processes experienced by South Asians as part of being an ethnic minority group. Individuals from the first generation used self‐management strategies congruent to traditional beliefs such as ‘sweating’ and often chose to travel to South Asian countries. Generations born and raised in the United Kingdom learnt and experimented with self‐management based on their fused identities and modified their approach depending on whether they were in familial or peer settings. Acculturative stress, which was typically higher in first generations who had migration‐related stressors, influenced the priority given to asthma self‐management throughout generations. The amount and type of available asthma information as well as social discussions within the community and with healthcare professionals also shaped asthma self‐management. CONCLUSIONS: Recognizing cultural diversity and its influence of asthma self‐management can help develop effective interventions tailored to the lives of South Asian people. PATIENT OR PUBLIC CONTRIBUTION: Patient and Public Involvement colleagues were consulted throughout to ensure that the study and its materials were fit for purpose

PACE and EISCAT radar observations of short-lived flow bursts on the nightside

Concurrent observations from two widely spaced radar experiments of quasi periodic flow bursts in the nightside are presented. The flow bursts closely resemble single radar observations reported by Williams et al. By using the Polar Anglo-American Conjugate Experiment (PACE) HF radar array at Halley Bay in conjunction with the EISCAT Common Program (CP) 2-D experiment, the flow bursts are shown to be a global phenomenon and important information as to their development and propagation can be determined

Ex vivo rabbit and human corneas as models for bacterial and fungal keratitis.

PURPOSE: In the study of microbial keratitis, in vivo animal models often require a large number of animals, and in vitro monolayer cell culture does not maintain the three-dimensional structure of the tissues or cell-to-cell communication of in vivo models. Here, we propose reproducible ex vivo models of single- and dual-infection keratitis as an alternative to in vivo and in vitro models. METHODS: Excised rabbit and human corneoscleral rims maintained in organ culture were infected using 10(8) cells of Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans or Fusarium solani. The infection was introduced by wounding with a scalpel and exposing corneas to the microbial suspension or by intrastromal injection. Post-inoculation, corneas were maintained for 24 and 48 h at 37 °C. After incubation, corneas were either homogenised to determine colony-forming units (CFU)/cornea or processed for histological examination using routine staining methods. Single- and mixed-species infections were compared. RESULTS: We observed a significant increase in CFU after 48 h compared to 24 h with S. aureus and P. aeruginosa. However, no such increase was observed in corneas infected with C. albicans or F. solani. The injection method yielded an approximately two- to 100-fold increase (p < 0.05) in the majority of organisms from infected corneas. Histology of the scalpel-wounded and injection models indicated extensive infiltration of P. aeruginosa throughout the entire cornea, with less infiltration observed for S. aureus, C. albicans and F. solani. The models also supported dual infections. CONCLUSIONS: Both scalpel wounding and injection methods are suitable for inducing infection of ex vivo rabbit and human cornea models. These simple and reproducible models will be useful as an alternative to in vitro and in vivo models for investigating the detection and treatment of microbial keratitis, particularly when this might be due to two infective organisms