Acute Mountain Sickness Symptom Severity at the South Pole: The Influence of Self-Selected Prophylaxis with Acetazolamide

INTRODUCTION

Acetazolamide, a carbonic anhydrase inhibitor, remains the only FDA approved pharmaceutical prophylaxis for acute mountain sickness (AMS) though its effectiveness after rapid transport in real world conditions is less clear.

METHODS

Over 2 years, 248 healthy adults traveled by airplane from sea level (SL) to the South Pole (ALT, ~3200m) and 226 participants provided Lake Louise Symptom Scores (LLSS) on a daily basis for 1 week; vital signs, blood samples, and urine samples were collected at SL and at ALT. Acetazolamide was available to any participant desiring prophylaxis. Comparisons were made between the acetazolamide with AMS (ACZ/AMS) (n = 42), acetazolamide without AMS (ACZ/No AMS)(n = 49), no acetazolamide with AMS (No ACZ/AMS) (n = 56), and the no acetazolamide without AMS (No ACZ/No AMS) (n = 79) groups. Statistical analysis included Chi-squared and one-way ANOVA with Bonferroni post-hoc tests. Significance was p≤0.05.

RESULTS

No significant differences were found for between-group characteristics or incidence of AMS between ACZ and No ACZ groups. ACZ/AMS reported greater LLSS, BMI, and red cell distribution width. ACZ/No AMS had the highest oxygen saturation (O2Sat) at ALT. No significant differences were found in serum electrolyte concentrations or PFT results.

DISCUSSION

Acetazolamide during rapid ascent provided no apparent protection from AMS based on LLSS. However, it is unclear if this lack of effect was directly associated with the drug or if perhaps there was some selection bias with individuals taking ACZ more likely to have symptoms or if there may have been more of perceptual phenomenon related to a constellation of side effects.

Stress granules and RNA processing bodies are novel autoantibody targets in systemic sclerosis

BACKGROUND

Autoantibody profiles represent important patient stratification markers in systemic sclerosis (SSc). Here, we performed serum-immunoprecipitations with patient antibodies followed by mass spectrometry (LC-MS/MS) to obtain an unbiased view of all possible autoantibody targets and their associated molecular complexes recognized by SSc.

METHODS

HeLa whole cell lysates were immunoprecipitated (IP) using sera of patients with SSc clinically positive for autoantibodies against RNA polymerase III (RNAP3), topoisomerase 1 (TOP1), and centromere proteins (CENP). IP eluates were then analyzed by LC-MS/MS to identify novel proteins and complexes targeted in SSc. Target proteins were examined using a functional interaction network to identify major macromolecular complexes, with direct targets validated by IP-Western blots and immunofluorescence.

RESULTS

A wide range of peptides were detected across patients in each clinical autoantibody group. Each group contained peptides representing a broad spectrum of proteins in large macromolecular complexes, with significant overlap between groups. Network analyses revealed significant enrichment for proteins in RNA processing bodies (PB) and cytosolic stress granules (SG) across all SSc subtypes, which were confirmed by both Western blot and immunofluorescence.

CONCLUSIONS

While strong reactivity was observed against major SSc autoantigens, such as RNAP3 and TOP1, there was overlap between groups with widespread reactivity seen against multiple proteins. Identification of PB and SG as major targets of the humoral immune response represents a novel SSc autoantigen and suggests a model in which a combination of chronic and acute cellular stresses result in aberrant cell death, leading to autoantibody generation directed against macromolecular nucleic acid-protein complexes.

Sleep disordered breathing and acute mountain sickness in workers rapidly transported to the South Pole (2835 m)

BACKGROUND

Sleep disordered breathing may be a risk factor for high altitude illness. Past Antarctic sleep studies suggest that rapid transport from sea level (SL) to the Amundsen Scott South Pole Station (SP, 2835 m) increases risk of Acute Mountain Sickness (AMS). We analyzed sleep studies in 38 healthy polar workers to explore the association between sleep disordered breathing and AMS after rapid transport to the South Pole.

METHODS

Subjects completed a baseline questionnaire, performed basic physiology tests, and were evaluated for AMS and medication use using an extended Lake Louise Questionnaire (LLQ) during their first week at the South Pole. Participants were included in this study if they took no medications and underwent polysomnography on their first nights at Sea Level and the South Pole using the Vivometrics LifeShirt(®). Within group changes were assessed with Wilcoxon signed rank tests and between group differences were assessed with Kruskal-Wallis rank sum tests.

RESULTS

Overall, 21/38 subjects met criteria for AMS at some time on or prior to the third morning at the South Pole. Subjective poor sleep quality was reported by both AMS (65%) and no AMS (41%) groups. The Apnea Hypopnea Index (AHI) increased significantly in both the AMS and no AMS groups, but the difference in the increase between the two groups was not statistically significant. Increased AHI was not associated with increased AMS symptoms. Previous altitude illness (p=0.06) and residence at low altitudes (p = 0.02) were risk factors for AMS.

CONCLUSION

AMS was not significantly associated with sleep architecture changes or increased AHI. However, AHI sharply increased at South Pole (19/38 participants) primarily due to central apneas. Those developing AMS were more likely to have experienced previous problems at altitude and reported living at lowland altitudes within the 3 months prior to rapid transport to the South Pole than those without AMS.

Effect of exercise on anthropometric measures and serum lipids in older individuals: a systematic review and meta-analysis

OBJECTIVES

Overweight and obesity are increasing in individuals over age 60 years. This systematic review quantifies the effect of exercise on body mass index (BMI), waist circumference (WC) and lipids in overweight and obese individuals over the age of 60 years.

SETTINGS

Nine randomised controlled trials conducted in Brazil, Great Britain, Iceland, Japan and the USA compared aerobic and/or resistance exercise with a control group.

PARTICIPANTS

Final analysis reviewed 1166 participants over the age of 60 years for 3-9 months.

PRIMARY OUTCOME MEASURES

This study reviewed the effects of exercise on BMI, WC and low-density lipoprotein (LDL).

RESULTS

Exercise produced a significant reduction in BMI (-1.01 kg/m(2), 95% CI -2.00 to -0.01) and WC (-3.09 cm, 95% CI -4.14 to -2.04) but not LDL cholesterol (-0.31 mg/dL, 95% CI -0.81 to 0.19). Analyses revealed substantial heterogeneity likely due to the type and intensity of exercise. Data on adverse effects were minimal. The overall level of evidence is moderate due to imprecision and heterogeneity.

CONCLUSIONS

Exercise in overweight and obese older individuals improves anthropometric measures such as BMI and WC. The effect of exercise on serum lipids is unclear.

Extremely preterm birth and adolescent mental health in a geographical cohort born in the 1990s

BACKGROUND

Preterm birth confers risk for poor outcome, including mental health problems. Survival of extremely preterm (EP; <28 weeks' gestation) or extremely low birthweight (ELBW; <1000 g) infants increased in the 1990s but psychiatric outcomes in older adolescents born preterm since 1990 are not well documented. This study aimed to characterize mental health and personality traits in a prospective geographical cohort of adolescents born EP/ELBW in Victoria, Australia in 1991 and 1992.

METHOD

At age 18 years, 215 EP/ELBW and 157 normal birthweight (>2499 g) control adolescents completed the Structured Clinical Interview for DSM-IV Disorders, Axis 1 Non-Patient version (SCID-I/NP), the Children's Interview for Psychiatric Syndromes (ChIPS) attention deficit hyperactivity disorder (ADHD) module, and questionnaires assessing recent depression and anxiety symptoms and personality traits.

RESULTS

ADHD prevalence was significantly elevated in EP/ELBW adolescents compared with controls [15% v. 7%; odds ratio (OR) 2.67, 95% confidence interval (CI) 1.08-6.58]. Aside from ADHD, however, EP/ELBW and control adolescents reported very similar outcomes, with other lifetime diagnoses identified in 23% of EP/ELBW and 21% of controls. These were predominantly mood and anxiety disorders (21% EP/ELBW, 20% controls). The groups did not differ in recent depression or anxiety symptoms assessed using questionnaires, and personality traits were also similar.

CONCLUSIONS

ADHD was more prevalent in EP/ELBW adolescents than controls, which is consistent with some, but not all, reports on preterm survivors born before the 1990s, and younger preterm children born in the 1990s. The high rates of anxiety and mood disorders were similar in both groups, and comparable with population-based estimates.

New stable isotope method to measure protein digestibility and response to pancreatic enzyme intake in cystic fibrosis

BACKGROUND & AIMS

Adequate protein intake and digestion are necessary to prevent muscle wasting in cystic fibrosis (CF). Accurate and easy-to-use methodology to quantify protein maldigestion is lacking in CF.

OBJECTIVE

To measure protein digestibility and the response to pancreatic enzyme intake in CF by using a new stable isotope methodology.

DESIGN

In 19 CF and 8 healthy subjects, protein digestibility was quantified during continuous (sip) feeding for 6 h by adding (15)N-labeled spirulina protein and L-[ring-(2)H5]phenylalanine (PHE) to the nutrition and measuring plasma ratio [(15)N]PHE to [(2)H5]PHE. Pancreatic enzymes were ingested after 2 h in CF and the response in protein digestibility was assessed. To exclude difference in mucosal function, postabsorptive whole-body citrulline (CIT) production rate was measured by L-[5-(13)C-5,5-(2)H2]-CIT pulse and blood samples were taken to analyze tracer-tracee ratios.

RESULTS

Protein digestibility was severely reduced in the CF group (47% of healthy subjects; P < 0.001). Intake of pancreatic enzymes induced a slow increase in protein digestibility in CF until 90% of values obtained by healthy subjects. Maximal digestibility was reached at 100 min and maintained for 80 min. Stratification into CF children (n = 10) and adults showed comparable values for protein digestibility and similar kinetic responses to pancreatic enzyme intake. Whole-body citrulline production was elevated in CF indicating preserved mucosal function.

CONCLUSION

Protein digestibility is severely compromised in patients with CF as measured by this novel and easy-to-use stable isotope approach. Pancreatic enzymes are able to normalize protein digestibility in CF, albeit with a severe delay. Registration ClinicalTrials.gov = NCT01494909.

Genotype and clinical care correlations in craniosynostosis: findings from a cohort of 630 Australian and New Zealand patients

Craniosynostosis is one of the most common craniofacial disorders encountered in clinical genetics practice, with an overall incidence of 1 in 2,500. Between 30% and 70% of syndromic craniosynostoses are caused by mutations in hotspots in the fibroblast growth factor receptor (FGFR) genes or in the TWIST1 gene with the difference in detection rates likely to be related to different study populations within craniofacial centers. Here we present results from molecular testing of an Australia and New Zealand cohort of 630 individuals with a diagnosis of craniosynostosis. Data were obtained by Sanger sequencing of FGFR1, FGFR2, and FGFR3 hotspot exons and the TWIST1 gene, as well as copy number detection of TWIST1. Of the 630 probands, there were 231 who had one of 80 distinct mutations (36%). Among the 80 mutations, 17 novel sequence variants were detected in three of the four genes screened. In addition to the proband cohort there were 96 individuals who underwent predictive or prenatal testing as part of family studies. Dysmorphic features consistent with the known FGFR1-3/TWIST1-associated syndromes were predictive for mutation detection. We also show a statistically significant association between splice site mutations in FGFR2 and a clinical diagnosis of Pfeiffer syndrome, more severe clinical phenotypes associated with FGFR2 exon 10 versus exon 8 mutations, and more frequent surgical procedures in the presence of a pathogenic mutation. Targeting gene hot spot areas for mutation analysis is a useful strategy to maximize the success of molecular diagnosis for individuals with craniosynostosis.

The State of Alaska's early experience with institutionalization of health impact assessment

BACKGROUND

Many nations routinely include health impact assessments (HIA) in public policy decisions. Institutionalization of HIA formally integrates health considerations into a governmental decision-making process. We describe an example of institutionalization in the United States through Alaska's early experience with institutionalization of HIA.

LITERATURE REVIEW

HIA arose from a series of health conferences in the 1970s that affirmed the importance of "health for all." A number of key milestones eventually defined HIA as a unique field of impact assessment. There are several approaches to institutionalization, and one common approach in the United States is through the National Environmental Policy Act (NEPA). NEPA formed the basis for the earliest HIAs in Alaska.

PROGRAM DESCRIPTION

Early HIAs in Alaska led to conferences, working groups, a state guidance document and the institutionalization of a HIA program within the Department of Health and Social Services in 2010. A medical epidemiologist staffs the program, which utilizes contractors to meet rising demand for HIA. The HIA program has sustainable funding from the state budget and from the state's natural resource permitting process. The HIA document is the main deliverable, but the program performs other tasks, including fieldwork and technical reviews. The HIA program works closely with a host of collaborative partners.

CONCLUSION

Alaska's institutionalized HIA program benefits from sustainable funding that promotes continuous quality improvement and involves the program in the entire life cycle of a development project. The program structure adapts well to variations in workflow and supports a host of quality control activities. Currently, the program focuses on HIAs for natural resource development projects.

A long-term evaluation of 150 costochondral nasal grafts

INTRODUCTION

This paper reviewed the outcome of cantilevered costochondral grafts used for dorsal nasal augmentation in the management of patients treated at the Australian Craniofacial Unit (ACFU), Adelaide over a 29-year period.

MATERIALS AND METHODS

All patients undergoing dorsal nasal augmentation with costochondral grafts as part of their craniofacial management between 1981 and 2009 were identified using the ACFU database, and their medical notes were reviewed.

RESULTS

107 patients (50 M, 57 F), with a mean age of 12.3 years (range: 2-62 years) and requiring a total of 150 costochondral grafts, were identified from the departmental database. Mean follow-up after nasal augmentation was 5.6 years (1 month-31.5 years). 46% of the patients were diagnosed with Binder syndrome/Chondrodysplasia punctata; other diagnoses included Tessier midline clefts, cleft lip and palate and frontonasal dysplasia. A dorsal midline incision (49%) was the commonest method of access, with 84% of patients having mini-screw fixation for graft stabilisation. Complications included screw palpability, infection, skin necrosis and graft fracture. The commonest reasons for a replacement graft were graft atrophy and fracture, infection and persistent deformity.

CONCLUSION

Cantilevered nasal costochondral grafting is an excellent technique for improving nasal contour and function in a wide variety of clinical situations.

Physiological variables associated with the development of acute mountain sickness at the South Pole

Exposure to altitudes >2500 m can result in acute mountain sickness (AMS), a mild and usually self-limiting condition. Research has attempted to identify factors associated with developing AMS without controlling important factors related to the ascent or collecting a comprehensive set of variables.

OBJECTIVES

The Antarctic Study of Altitude Physiology (ASAP) investigated variables associated with the development of AMS in adults experiencing rapid passive transport to altitude by airplane.

DESIGN

Our prospective observational trial collected data, including personal history, anthropometrics, vital signs, blood samples and pulmonary function, at sea level and at altitude. Statistical analysis utilised independent sample t tests to investigate between-group differences (p<0.05) and a forward, step-wise binary logisitic regression analysis was performed.

PARTICIPANTS

Of 248 eligible ASAP participants, those who did not use acetazolamide (N=98) were included in the present analysis.

PRIMARY OUTCOME MEASURES

The diagnosis of AMS using the Lake Louise Symptom Score.

RESULTS

Analysis of participants not using acetazolamide (n=90) found 30 participants developed AMS and 60 participants did not. Estimated plasma volume decreased significantly at altitude (p=0.025) in the AMS group as compared with the No AMS group while body weight did not change (p=0.125). Serum sodium (p=0.045) and low-density lipoprotein (LDL) (p=0.049) levels were higher in the No AMS group. A logistic regression analysis emphasised the contributions of LDL and eosinophil levels in the development of AMS.

CONCLUSIONS

These results suggest that the body water regulation and inflammation are key factors in AMS development when all other factors such as the level of physical exertion during ascent, the rate and magnitude of ascent and the use of acetazolamide are controlled.

The translational repressor T-cell intracellular antigen-1 (TIA-1) is a key modulator of Th2 and Th17 responses driving pulmonary inflammation induced by exposure to house dust mite

T-cell intracellular antigen-1 (TIA-1) is a translational repressor that dampens the production of proinflammatory cytokines and enzymes. In this study we investigated the role of TIA-1 in a mouse model of pulmonary inflammation induced by exposure to the allergenic extract (Df) of the house dust mite Dermatophagoides farinae. When intranasally challenged with a low dose of Df, mice lacking TIA-1 protein (Tia-1(-/-)) showed more severe airway and tissue eosinophilia, infiltration of lung bronchovascular bundles, and goblet cell metaplasia than wild-type littermates. Tia-1(-/-) mice also had higher levels of Df-specific IgE and IgG(1) in serum and ex vivo restimulated Tia-1(-/-) lymph node cells and splenocytes transcribed and released more Th2/Th17 cytokines. To evaluate the site of action of TIA-1, we studied the response to Df in bone marrow chimeras. These experiments revealed that TIA-1 acts on both hematopoietic and non-hematopoietic cells to dampen pulmonary inflammation. Our results identify TIA-1 as a negative regulator of allergen-mediated pulmonary inflammation in vivo. Thus, TIA-1 might be an important player in the pathogenesis of bronchial asthma.

Longitudinal predictors of psychiatric disorders in very low birth weight adults

The purpose of this study was to determine risk and protective factors for adult psychiatric disorders in very low birth weight (VLBW, birth weight <1,501 g) survivors. 79 of 154 (51%) VLBW subjects recruited at birth were assessed in early adulthood (24-27 years). Participants were screened for a psychiatric disorder; those elevated were invited to attend a structured clinical interview to determine a clinical diagnosis. Longitudinal variables measured from birth and at ages 2, 5, 14 and 18 years were included in analyses. Perinatal, developmental and social environmental risk factors failed to predict psychiatric disorder in adulthood in this cohort of VLBW survivors. Instead, low self-esteem at age 18 (odds ratio [OR] = 1.05, 95% confidence interval [CI] = 1, 1.11, p = 0.05) and the adult social environment (high rates of negative life event stress at the time of assessment: OR = 1.39, CI = 1.10, 1.76, p = 0.02), contributed significantly to adult psychiatric outcomes.

Prevalence of psychiatric diagnoses in preterm and full-term children, adolescents and young adults: a meta-analysis

BACKGROUND

Preterm (PT) birth and low birth weight (LBW) are high-prevalence events that are associated with adverse outcomes in the longer term, with vulnerability increasing as maturity at birth decreases. Psychiatric symptomatology appears heightened in PT/LBW survivors, though there are some discordant findings from studies using questionnaire measures, particularly with respect to anxiety and depressive symptoms.

METHOD

This article synthesises findings from research using clinical psychiatric diagnostic criteria in PT/LBW individuals aged 10-25 years compared with term-born peers. Key outcomes of interest were the rates of individuals receiving any psychiatric diagnosis and the number of diagnoses of anxiety or depressive disorders.

RESULTS

A literature search for studies reporting prevalence of 'any diagnosis' yielded five studies that met inclusion criteria, with a total of 565 PT/LBW and 533 control individuals. Also, five studies were found that reported rates of anxiety/depression (692 PT/LBW and 605 control individuals). The risk of these outcomes was increased for PT/LBW individuals compared with controls [any diagnosis: odds ratio (OR) 3.66, 95% confidence interval (CI) 2.57-5.21; anxiety or depressive disorder: OR 2.86, 95% CI 1.73-4.73].

CONCLUSIONS

The studies reviewed here indicate that, in addition to monitoring and management of medical and cognitive sequelae, the psychological well-being of PT/LBW individuals should be a key part of ongoing care.

Changing long-term outcomes for infants 500-999 g birth weight in Victoria, 1979-2005

OBJECTIVE

To determine the survival and neurological outcome at 2 years of age of extremely low birthweight (ELBW, birth weight 500-999 g) infants born in the state of Victoria compared with term controls, and contrasted with ELBW cohorts from previous eras.

DESIGN AND SETTING

A population-based cohort study of consecutive ELBW infants born during 2005 in the state of Victoria, and also in 1979-1980, 1985-1987, 1991-1992 and 1997.

PARTICIPANTS

All 257 live births free of lethal malformations weighing 500-999 g in 2005, 220 randomly selected term, normal birthweight (birth weight >2499 g) controls, and equivalent cohorts born in earlier eras.

MAIN OUTCOME MEASURES

Survival rates and quality-adjusted survival rates at 2 years of age, contrasted between cohorts.

RESULTS

Of 257 ELBW live births in 2005, 66.9% survived to 2 years of age, significantly lower than the survival rate of 75.2% for 1997 (odds ratio (OR) 0.67, 95% CI 0.45 to 0.99, p=0.046), but not after adjustment for confounders of birth weight, gestational age and gender (adjusted OR 0.73, 95% CI 0.46 to 1.16, p=0.18). This was a reversal of the steady increase in survival rates up to 1997. Rates of blindness, severe developmental delay and severe disability were significantly lower in 2005 than in ELBW survivors from previous eras. Consequently the difference in the quality-adjusted survival rates between 2005 and 1997 was only -3.8% (95% CI -11.4% to 3.7%, p=0.32).

CONCLUSIONS

Regional survival rates for ELBW infants have plateaued since the late 1990s, but the neurosensory outcome in survivors has improved in 2005.

High signal intensity on T2-weighted MR imaging at term-equivalent age in preterm infants does not predict 2-year neurodevelopmental outcomes

BACKGROUND AND PURPOSE

DEHSI on T2-weighted MR imaging in preterm infants at term-equivalent age has been regarded as an unfavorable marker for neurodevelopmental outcome. The aim of this study was to examine the relationship between the presence and extent of DEHSI and neurodevelopmental outcomes.

MATERIALS AND METHODS

We evaluated the MR images of 160 preterm infants at term-equivalent age. The presence of DEHSI was evaluated in separate regions and classified into 5 grades based on the extent of DEHSI. We also examined within those infants with DEHSI, whether typical signal-intensity characteristics of the posterior periventricular crossroads region were visible. Finally, ADC and FA values within the white matter were analyzed. Neurodevelopmental outcomes were assessed at 2-year corrected age with a standardized neurologic examination and the BSID-II.

RESULTS

The grade of DEHSI had significant linear trends with increasing ADC and a trend toward lower FA values. However, there was no relationship between the degree of DEHSI and 2-year neurodevelopmental outcomes. In contrast, 13 infants with DEHSI who did not have visible posterior crossroads had poorer neurodevelopmental outcomes compared with infants with visible posterior crossroads.

CONCLUSIONS

Although DEHSI may represent disturbances in white matter structure, as illustrated by its relationship to altered ADC and FA values, there is no relationship to short-term neurodevelopment outcome unless there are invisible posterior crossroads, representing a severe form of global high T2 signal intensity.

Incidence and Symptoms of High Altitude Illness in South Pole Workers: Antarctic Study of Altitude Physiology (ASAP)

Introduction:

Each year, the US Antarctic Program rapidly transports scientists and support personnel from sea level (SL) to the South Pole (SP, 2835 m) providing a unique natural laboratory to quantify the incidence of acute mountain sickness (AMS), patterns of altitude related symptoms and the field effectiveness of acetazolamide in a highly controlled setting. We hypothesized that the combination of rapid ascent (3 hr), accentuated hypobarism (relative to altitude), cold, and immediate exertion would increase altitude illness risk.

Methods:

Medically screened adults (N = 246, age = 37 ± 11 yr, 30% female, BMI = 26 ± 4 kg/m²) were recruited. All underwent SL and SP physiological evaluation, completed Lake Louise symptom questionnaires (LLSQ, to define AMS), and answered additional symptom related questions (eg, exertional dyspnea, mental status, cough, edema and general health), during the 1st week at altitude. Acetazolamide, while not mandatory, was used by 40% of participants.

Results:

At SP, the barometric pressure resulted in physiological altitudes that approached 3400 m, while T °C averaged −42, humidity 0.03%. Arterial oxygen saturation averaged 89% ± 3%. Overall, 52% developed LLSQ defined AMS. The most common symptoms reported were exertional dyspnea-(87%), sleeping difficulty-(74%), headache-(66%), fatigue-(65%), and dizziness/lightheadedness-(46%). Symptom severity peaked on days 1–2, yet in >20% exertional dyspnea, fatigue and sleep problems persisted through day 7. AMS incidence was similar between those using acetazolamide and those abstaining (51 vs. 52%, P = 0.87). Those who used acetazolamide tended to be older, have less altitude experience, worse symptoms on previous exposures, and less SP experience.

Conclusion:

The incidence of AMS at SP tended to be higher than previously reports in other geographic locations at similar altitudes. Thus, the SP constitutes a more intense altitude exposure than might be expected considering physical altitude alone. Many symptoms persist, possibly due to extremely cold, arid conditions and the benefits of acetazolamide appeared negligible, though it may have prevented more severe symptoms in higher risk subjects.