Effect of focal low-frequency stimulation on amygdala-kindled afterdischarge thresholds and seizure profiles in fast- and slow-kindling rat strains

Purpose: To determine whether low-frequency, 1-Hz sine-wave stimulation (LFS) applied to a fully kindled amygdala focus would show antiepileptic properties in rats that were either naturally seizure prone (Fast) or seizure resistant (Slow). Methods: Normal twisted and/or "spanning" bipolar electrode configurations were implanted in the amygdalae of adult male Fast and Slow rats. In experiment one, rats were kindled daily to stage-5 levels through one electrode type until stable afterdischarge thresholds (ADTs) were obtained. Next, LFS was applied through the kindled electrode, and ADTs were redetermined 1 min later, and daily for a week, without reapplying the LFS. In experiment two, a single, normal bipolar kindling electrode was implanted in the amygdala and centered between two poles of a spanning electrode. After stable kindled ADTs were obtained, LFS was applied to the amygdala "area" through the spanning electrode. ADTs were redetermined at the kindled electrode as earlier. Results: LFS through the kindling electrode had no effect on ADTs 1 min later, but the ADTs increased dramatically 24 h later and then slowly returned to baseline over days. In experiment two, LFS applied through the nonkindled spanning electrode also showed a small but significant threshold elevation at the interposing kindled electrode. Importantly, no obvious neuropathology was associated with these LFS treatments. Conclusions: LFS applied directly to the kindled network has significant threshold-elevating properties that are less evident when applied to the "general area"; here LFS must be delivered through a larger surface area and/or at higher intensity.     

The value of hyoscine butylbromide in pelvic MRI

AIM: To evaluate the effect of hyoscine butylbromide (HBB) on image quality and lesion and organ visualization in pelvic magnetic resonance imaging (MRI) MATERIALS AND METHODS: A prospective, ethically approved study was undertaken of 47 patients attending for pelvic MRI at a cancer centre. T2-weighted transverse and sagittal sequences were performed before and after intravenous injection of 20 mg HBB. Three radiologists independently scored anonymized image series for overall image quality, visualization of pelvic lesions and visualization of individual pelvic organs. Statistical analysis was performed to assess improvements in radiologists' scores post-HBB administration. Radiologists also assessed pre-HBB administration T1-weighted images for degree of bowel peristalsis to determine whether this could predict improvement in post-HBB T2-weighted image scores. Side effects of HBB were recorded using a patient questionnaire. RESULTS: Radiologists' scores for image quality and lesion visualization were significantly higher on the post-HBB administration T2-weighted series (p<0.0005). Scores for the visualization of the bladder, rectum, pelvic bowel, prostate, and seminal vesicles (all p<0.0005), cervix (p=0.019) and vagina (p=0.0001) were also significantly higher post-HBB administration. Scores for the degree of peristalsis on T1-weighted images were not related to improvement in image quality or lesion visualization on T2-weighted images post-HBB administration. Side effects of HBB were mild and self-limiting. CONCLUSION: Intravenous HBB administration improves image quality and lesion visualization in oncological pelvic MRI and is recommended for routine use.     

Determinants of protection among HIV‐exposed seronegative persons: an overview

Both clinical experience and a growing medical literature indicate that some persons who have been exposed to human immunodeficiency virus (HIV) infection remain uninfected. Although in some instances this may represent good fortune, cohorts of uninfected persons have been reported who are considered at high risk for infection. In these cohorts a variety of characteristics have been proposed as mediating protection, but to date only the 32–base pair deletion in the chemokine (C‐C motif) receptor 5 gene, which results in complete failure of cell surface expression of this coreceptor, has been associated with high‐level protection from HIV infection. With this in mind, there are probably many other factors that may individually or in combination provide some level of protection from acquisition of HIV infection. Because some of these factors are probably incompletely protective or inconsistently active, identifying them with confidence will be difficult. Nonetheless, clarifying the determinants of protection against HIV infection is a high priority that will require careful selection of high‐risk uninfected cohorts, who should undergo targeted studies of plausible mediators and broad screening for unexpected determinants of protection.     

The effects of normal aging on sleep spindle and K-complex production.

OBJECTIVES: Despite a relatively large body of literature describing the characteristics of sleep spindles and K-complexes in young adults, relatively little research has been conducted in older individuals. The general consensus from the few studies that have addressed this issue is that there is a progressive decrease in the number of spindles and K-complexes with age, although there is large intra-individual variation. Whether or not these changes are an inevitable consequence of the aging process can be addressed by studying healthy older adults who provide an example of the effects of age independently from those of disease.METHODS: Fourteen young adults (mean age=21.4+/-2.5 years) and 20 older adults (mean age=75.5+/-6.3 years) participated in the study. All subjects were neurologically and medically healthy and were not taking any medications with a known effect on the central nervous system or sleep. For each subject, a number of characteristics were determined including the number, density (SS/min), amplitude and frequency of all spindles as well as the number and density of K-complexes (KC/min).RESULTS: Spindle number, density and duration as well as K-complex number and density were all significantly lower in the elderly compared to the young adults. The EEG frequency within the spindles was significantly higher in the elderly, although the absolute difference was less than 0.5 Hz. Multiple regression analysis indicated that spindle duration and K-complex density were able to predict over 90% of the variance in age.CONCLUSIONS: The age-related decrease in sleep spindle and K-complex density is consistent with previous reports and may be interpreted as an age-related alteration of thalamocortical regulatory mechanisms.     

Nurse-led dexmedetomidine sedation for magnetic resonance imaging in children: a 6-year quality improvement project

We aimed to safely introduce dexmedetomidine into a nurse-led sedation service for magnetic resonance imaging in children. Secondary aims were to increase the number of children eligible for sedation and to increase the actual number of children having sedation performed by our nurse sedation team. We analysed 1768 consecutive intravenous and 219 intranasal dexmedetomidine sedation episodes in infants, children and adolescents having magnetic resonance imaging scans between March 2016 and March 2022. The overall sedation success rate was 98.4%, with a 98.9% success rate for intravenous dexmedetomidine and a 95.0% success rate for intranasal dexmedetomidine. The incidence of scan interruption during intravenous and intranasal dexmedetomidine sedation was 8.8% and 21.9%, respectively. We conclude that paediatric sedation with dexmedetomidine for magnetic resonance scanning is safe and successful.     

Beyond the Page: A Process Review of Using Ethnodrama to Disseminate Research Findings

Public health researchers are charged with communicating study findings to appropriate audiences. Dissemination activities typically target the academic research community. However, as participatory research grows, researchers are increasingly exploring innovative dissemination techniques to reach broader audiences, particularly research participants and their communities. One technique is ethnodrama/ethnotheatre, a written or live performance based on study findings. Though used effectively in social change programs, dramas are seldom used to distribute research findings exclusively. Therefore, little information is available about planning and implementing an ethnodrama for this purpose. We present a case study describing the process of planning and implementing an ethnodrama in the context of the Durham Focus Group Study, which explored men’s health-seeking behaviors and experiences with health and healthcare services in Durham, North Carolina. Here, we highlight lessons learned throughout the production of the ethnodrama, and how we addressed challenges associated with transforming research data into educational entertainment. Additionally, we provide discussion of audience feedback, which indicated that our ethnodrama evoked an urgency to change health behaviors among lay persons (67%) and delivery of health services among those identifying as providers (84%), pointing to the success of the performance in both entertaining and educating the audience.