The Adrenocortical Response to Synthetic ACTH Following a Trek to High Altitude

Gradual ascent to high altitude is typically associated with reduced resting aldosterone and unchanged cortisol, features that may facilitate acclimatization but are poorly understood. The aim of the study was to investigate the cortisol and aldosterone response to adrenocorticotrophic hormone at altitude. Eleven subjects underwent a 250 μg short synacthen test at sea-level and again after trekking to 3 600 m in Nepal. Cortisol and aldosterone were measured by conventional assay from blood samples taken immediately prior to the administration of synacthen (T0) and then 30 (T30) and 60 (T60) min later. At 3 600 m resting basal cortisol and aldosterone levels were both significantly lower than they were at sea-level (p=0.004, p=0.003, respectively). Cortisol values at T30 and T60 were not different between sea-level and 3 600 m but the increment after synacthen was significantly greater (p=0.041) at 3 600 m due to a lower basal value. Aldosterone at T30 and T60 was significantly lower (p=0.003 for both) at 3 600 m than at sea-level and the increment following synacthen was also significantly less (p=0.003) at 3 600 m. At 3 600 m there appears to be a divergent adrenal response to synthetic adrenocorticotrophic hormone with an intact cortisol response but a reduced aldosterone response, relative to sea-level. This may reflect a specific effect of hypoxia on aldosterone synthesis and may be beneficial to acclimatization.

Assay for Ubiquitin Ligase Activity: High-Throughput Screen for Inhibitors of HDM2

An assay for the autoubiquitination activity of the E3 ligaseHDM2 (Mdm2) was developed and adapted to a high-throughput format to identify inhibitors of this activity. The assay can also be used tomeasure the activity of other E3s andmay be useful in finding both inhibitors and activators of a wide range of different ubiquitin ligases.

Missing voices: Profile and extent of acquired communication disorders in Aboriginal and non-Aboriginal adult stroke survivors in Western Australia using linked administrative records

Background

Limited data exist on the extent of specific functional sequelae, including acquired communication disorder, among Aboriginal stroke survivors, making planning of multidisciplinary services difficult.

Aims

To obtain estimates of the extent and profile of acquired communication disorder in Aboriginal and non-Aboriginal adult stroke survivors in Western Australia and investigate potential disparities in receiving in-hospital speech pathology services among survivors with acquired communication disorder.

Methods

Stroke cases surviving their first stroke episode during 2002–2011 were identified using Western Australia-wide person-based linked hospital and mortality data, and their five-year comorbidity profiles determined. The mid-year prevalence of stroke cases with acquired communication disorder was estimated for 2011. Regression methods were used to investigate determinants of receiving speech pathology services among acquired communication disorder cases.

Results

Of 14,757 stroke survivors aged 15–79 years admitted in 2002–2011, 33% had acquired communication disorder (22% aphasia/dysphasia) and 777 (5.3%) were Aboriginal. Aboriginal patients were more likely to be younger, live remotely, and have comorbidities. A diagnosis of aphasia was more common in Aboriginal than non-Aboriginal patients 15–44 years (p = 0.003). A minimum of 107 Aboriginal and 2324 non-Aboriginal stroke patients with acquired communication disorder lived in Western Australia in 2011. Aboriginal status was not associated with receiving in-hospital speech services among acquired communication disorder patients in unadjusted or adjusted models.

Conclusions

The relative youth, geographical distribution, high comorbidity prevalence, and cultural needs of Aboriginal stroke patients with acquired communication disorder should inform appropriate service design for speech pathology and rehabilitation. Innovative models are required to address workforce issues, given low patient volumes.

Case ascertainment of heat illness in the British Army: evidence of under-reporting from analysis of Medical and Command notifications, 2009-2013

Background

Heat illness in the Armed Forces is considered preventable. The UK military relies upon dual Command and Medical reporting for case ascertainment, investigation of serious incidents and improvement of preventive practices and policy. This process could be vulnerable to under-reporting.

Objectives

To establish whether heat illness in the British Army has been under-reported, by reviewing concordance of reporting to the Army Incident Notification Cell (AINC) and the Army Health Unit (AHU) and to characterise the burden of heat illness reported by these means.

Methods

Analysis of anonymised reporting databases held by the AHU and AINC, for the period 2009–2013.

Results

565 unique cases of heat illness were identified. Annual concordance of reporting ranged from 9.6% to 16.5%. The overall rate was 13.3%. July was the month with the greatest number of heat illness reports (24.4% of total reporting) and the highest concordance rate (30%). Reports of heat illness from the UK (n=343) exceeded overseas notifications (n=221) and showed better concordance (17.1% vs 12.8%). The annual rate of reported heat illness varied widely, being greater in full-time than reservist personnel (87 vs 23 per100 000) and highest in full-time untrained personnel (223 per100 000).

Conclusions

The risk of heat illness was global, year-round and showed dynamic local variation. Failure to dual-report casualties impaired case ascertainment of heat illness across Command and Medical chains. Current preventive guidance, as applied in training and on operations, should be critically evaluated to ensure that risk of heat illness is reduced as low as possible. Clear procedures for casualty notification and surveillance are required in support of this and should incorporate communication within and between the two reporting chains.

Physiology studies at high altitude; why and how

The military has always had an important role in high altitude research. This is due to the fact that mountainous regions often span borders and provide a safe haven to enemies. Deploying troops rapidly into high altitude environments presents major problems in terms of the development of high altitude illness. This paper examines the rationale for carrying out research at high altitude and the opportunities within the UK Defence Medical Services for carrying out this research.

Where do pulse oximeter probes break?

Pulse oximetry, a non-invasive method for accurate assessment of blood oxygen saturation (SPO2), is an important monitoring tool in health care facilities. However, it is often not available in many low-resource settings, due to expense, overly sophisticated design, a lack of organised procurement systems and inadequate medical device management and maintenance structures. Furthermore medical devices are often fragile and not designed to withstand the conditions of low-resource settings. In order to design a probe, better suited to the needs of health care facilities in low-resource settings this study aimed to document the site and nature of pulse oximeter probe breakages in a range of different probe designs in a low to middle income country. A retrospective review of job cards relating to the assessment and repair of damaged or faulty pulse oximeter probes was conducted at a medical device repair company based in Cape Town, South Africa, specializing in pulse oximeter probe repairs. 1,840 job cards relating to the assessment and repair of pulse oximeter probes were reviewed. 60.2 % of probes sent for assessment were finger-clip probes. For all probes, excluding the neonatal wrap probes, the most common point of failure was the probe wiring (>50 %). The neonatal wrap most commonly failed at the strap (51.5 %). The total cost for quoting on the broken pulse oximeter probes and for the subsequent repair of devices, excluding replacement components, amounted to an estimated ZAR 738,810 (USD $98,508). Improving the probe wiring would increase the life span of pulse oximeter probes. Increasing the life span of probes will make pulse oximetry more affordable and accessible. This is of high priority in low-resource settings where frequent repair or replacement of probes is unaffordable or impossible.

Heat illness in military populations: asking the right questions for research

Reports of death and injury in military populations due to exertional heat illness (EHI) and its most severe form, exertional heat stroke, date from antiquity. Yet, understanding of why one soldier may succumb to EHI, while those around him do not, is incomplete. This paper sets out research questions in support of the health of military populations who may experience exertional heat stress. The mechanisms by which excess body heat arises and is dissipated are outlined and the significance of core temperature measurement during exercise is discussed. Known risk factors for EHI are highlighted and new approaches for identifying individual vulnerability to EHI are introduced. A better understanding of the underlying pathophysiology may allow the effective use of biomarkers in future risk stratification and identification of EHI, allied to emerging genetic technologies. The thermal burden associated with states of dress and personal protection of Service personnel in their worldwide duties should be a focus of research as new equipment is introduced. At all times, the discerning use of existing guidance by Commanders on the ground will remain a mainstay of preventing EHI.

Technique for high axial shielding factor performance of large-scale, thin, open-ended, cylindrical Metglas magnetic shields

Metglas 2705M is a low-cost commercially available, high-permeability cobalt-based magnetic alloy, provided as a 5.08-cm wide and 20.3-μm thick ribbon foil. We present an optimized construction technique for single-shell, large-scale (human-size), thin, open-ended cylindrical Metglas magnetic shields. The measured dc axial and transverse magnetic shielding factors of our 0.61-m diameter and 1.83-m long shields in the Earth's magnetic field were 267 and 1500, for material thicknesses of only 122 μm (i.e., 6 foil layers). The axial shielding performance of our single-shell Metglas magnetic shields, obtained without the use of magnetic shaking techniques, is comparable to the performance of significantly thicker, multiple-shell, open-ended Metglas magnetic shields in comparable-magnitude, low-frequency applied external fields reported previously in the literature.