Experimental traumatic brain injury (TBI) studies report the neuroprotective effects of female sex steroids on multiple mechanisms of injury, with the clinical assumption that women have hormonally ...mediated neuroprotection because of the endogenous presence of these hormones. Other literature indicates that testosterone may exacerbate injury. Further, stress hormone abnormalities that accompany critical illness may both amplify or blunt sex steroid levels. To better understand the role of sex steroid exposure in mediating TBI, we 1) characterized temporal profiles of serum gonadal and stress hormones in a population with severe TBI during the acute phases of their injury; and 2) used a biological systems approach to evaluate these hormones as biomarkers predicting global outcome. The study population was 117 adults (28 women; 89 men) with severe TBI. Serum samples (n=536) were collected for 7 days post-TBI for cortisol, progesterone, testosterone, estradiol, luteinizing hormone (LH), and follicle-stimulating hormone (FSH). Hormone data were linked with clinical data, including acute care mortality and Glasgow Outcome Scale (GOS) scores at 6 months. Hormone levels after TBI were compared to those in healthy controls (n=14). Group based trajectory analysis (TRAJ) was used to develop temporal hormone profiles that delineate distinct subpopulations in the cohort. Structural equations models were used to determine inter-relationships between hormones and outcomes within a multivariate model. Compared to controls, acute serum hormone levels were significantly altered after severe TBI. Changes in the post-TBI adrenal response and peripheral aromatization influenced hormone TRAJ profiles and contributed to the abnormalities, including increased estradiol in men and increased testosterone in women. In addition to older age and greater injury severity, increased estradiol and testosterone levels over time were associated with increased mortality and worse global outcome for both men and women. These findings represent a paradigm shift when thinking about the role of sex steroids in neuroprotection clinically after TBI.
We have compared 2433 nights of Rayleigh lidar temperatures measured at
L'Observatoire de Haute Provence (OHP) with co-located temperature
measurements from the Microwave Limb Sounder (MLS) and the ...Sounding of the
Atmosphere by Broadband Emission Radiometry instrument (SABER). The
comparisons were conducted using data from January 2002 to March 2018 in the
geographic region around the observatory (43.93∘ N,
5.71∘ E). We have found systematic differences between the
temperatures measured from the ground-based lidar and those measured from the
satellites, which suggest non-linear distortions in the satellite altitude
retrievals. We see a winter stratopause cold bias in the satellite
measurements with respect to the lidar (−6 K for SABER and −17 K
for MLS), a summer mesospheric warm bias (6 K near 60 km), and a
vertically structured bias for MLS (−4 to 4 K). We have corrected the
stratopause height of the satellite measurements using the lidar temperatures
and have seen an improvement in the comparison. The winter relative cold bias
between the lidar and SABER has been reduced to 1 K in both the stratosphere
and mesosphere and the summer mesospheric warm bias is reduced to 2 K.
Stratopause altitude corrections have reduced the relative cold bias between
the lidar and MLS by 4 K in the early autumn and late spring but were
unable to address the apparent vertical oscillations in the MLS temperature
profiles.
The objective of this paper and its companion (Wing et al., 2018) is to show
that ground-based lidar temperatures are a stable, accurate, and precise
data set for use in validating satellite ...temperatures at high vertical
resolution. Long-term lidar observations of the middle atmosphere have been
conducted at the Observatoire de Haute-Provence (OHP), located in southern
France (43.93∘ N, 5.71∘ E), since 1978. Making use of
20 years of high-quality co-located lidar measurements, we have shown that
lidar temperatures calculated using the Rayleigh technique at 532 nm are
statistically identical to lidar temperatures calculated from the
non-absorbing 355 nm channel of a differential absorption lidar (DIAL)
system. This result is of interest to members of the Network for the
Detection of Atmospheric Composition Change (NDACC) ozone lidar community
seeking to produce validated temperature products. Additionally, we have
addressed previously published concerns of lidar–satellite relative warm bias
in comparisons of upper-mesospheric and lower-thermospheric (UMLT)
temperature profiles. We detail a data treatment algorithm which minimizes
known errors due to data selection procedures, a priori choices, and
initialization parameters inherent in the lidar retrieval. Our algorithm
results in a median cooling of the lidar-calculated absolute temperature
profile by 20 K at 90 km altitude with respect to the standard OHP
NDACC lidar temperature algorithm. The confidence engendered by the long-term
cross-validation of two independent lidars and the improved lidar temperature
data set is exploited in Wing et al. (2018) for use in multi-year satellite
validations.
Abstract
Omicron has become the dominant SARS-CoV-2 variant globally since December 2021, with distinct waves being associated with separate Omicron sublineages. Rapid detection of BA.1, BA.2, BA.4, ...and BA.5 was accomplished in the province of Alberta, Canada, through the design and implementation of real-time reverse transcriptase PCR assays targeting S:N501Y, S:ins214EPE, S:H69/V70, ORF7b:L11F, and M:D3N. Using the combination of results for each of these markers, samples could be designated as belonging to sublineages within BA.1, BA.2, BA.4, or BA.5. The analytical sensitivity of these markers ranged from 132 to 2229 copies/mL and in-laboratory accuracy was 98.9–100%. A 97.3% agreement using 12,592 specimens was demonstrated for the assays compared to genome sequencing. The use of these assays, combined with genome sequencing, facilitated the surveillance of SARS-CoV-2 lineages throughout a BA.5-dominated period.
Primary objectives: To describe hormone profiles for pre-/post-menopausal women, to monitor time to resumption of menstruation among pre-menopausal women and to describe cortisol associated LH ...suppression and phasic variation in other sex hormones over timeMethods and procedures: This study determined amenorrhea duration and characterized acute (days 0-7) and chronic (months 1-6) gonadotropins luteinizing hormone and follicle stimulating hormone (LH, FSH), sex hormones (progesterone, estradiol) and stress hormone (cortisol) profiles. Women were pre-menopausal (n = 3) or post-menopausal (n = 3). Among pre-menopausal women, menstrual cycle resolution and phase association (luteal/follicular) was monitored using self-report monthly reproductive history questionnaires. This study compared post-TBI hormone profiles, stratified by menopausal status, to hormone levels from seven controls and described 6- and 12-month outcomes for these women.Main outcomes and results: Consistent with functional hypothalamic amenorrhea (FHA), menstruation resumption among pre-menopausal women occurred when serum cortisol normalized to luteal phase control levels. For post-menopausal women, serum cortisol reductions corresponded with resolution of suppressed LH levels.Conclusions: The stress of TBI results in anovulation and central hypothalamic-pituitary-ovarian (HPG) axis suppression. Future work will examine acute/chronic consequences of post-TBI hypercortisolemia and associated HPG suppression, the temporal association of HPG suppression with other neuroendocrine adaptations and how HPG suppression impacts multidimensional recovery for women with TBI.
Previous studies have identified finely laminated, or layered, features within Arctic clouds. This study focuses on quasi-horizontal layers that are 7.5 to 30 m thick, within clouds from 0 to 5 km ...altitude. No pre-selection for any particular cloud types was made prior to the identification of laminations. We capitalize on the 4-year measurement record available from Eureka, Nunavut (79.6∘ N, 85.6∘ W), using the Canadian Network for the Detection of Atmospheric Composition Change (CANDAC) Rayleigh–Mie–Raman Lidar (CRL; 1 min, 7.5 m resolution). Laminated features are identified on 18% of all days, from 2016–2019. Their presence is conclusively excluded on 12% of days. March, April, and May have a higher measurement cadence and show laminations on 41% of days. Individual months show laminations on up to 50% of days. Our results suggest that laminations are not rare phenomena at Eureka. To determine laminations’ likely contribution to Arctic weather and climate, local weather reports were obtained from the nearby Environment and Climate Change Canada (ECCC) weather station. Days with laminated clouds are strongly correlated with precipitating snow (r = 0.63), while days with non-laminated clouds (r = −0.40) and clear sky days (r = −0.43) are moderately anti-correlated with snow precipitation.
Despite significant advances in the management of head trauma, there remains a lack of pharmacological treatment options for traumatic brain injury (TBI). While progesterone clinical trials have ...shown promise, corticosteroid trials have failed. The purpose of this study was to (1) characterize endogenous cerebrospinal fluid (CSF) progesterone and cortisol levels after TBI, (2) determine relationships between CSF and serum profiles, and (3) assess the utility of these hormones as predictors of long-term outcomes. We evaluated 130 adults with severe TBI. Serum samples (n=538) and CSF samples (n=746) were collected for 6 days post-injury, analyzed for cortisol and progesterone, and compared with healthy controls (n=13). Hormone data were linked with clinical data, including Glasgow Outcome Scale (GOS) scores at 6 and 12 months. Group based trajectory (TRAJ) analysis was used to develop temporal hormone profiles delineating distinct subpopulations. Compared with controls, CSF cortisol levels were significantly and persistently elevated during the first week after TBI, and high CSF cortisol levels were associated with poor outcome. As a precursor to cortisol, progesterone mediated these effects. Serum and CSF levels for both cortisol and progesterone were strongly correlated after TBI relative to controls, possibly because of blood-brain barrier disruption. Also, differentially impaired hormone transport and metabolism mechanisms after TBI, potential de novo synthesis of steroids within the brain, and the complex interplay of cortisol and pro-inflammatory cytokines may explain these acute hormone profiles and, when taken together, may help shed light on why corticosteroid trials have previously failed and why progesterone treatment after TBI may be beneficial.
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