Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

The Role of Neurogranin in Synaptic Dysfunction after Experimental Traumatic Brain Injury

Traumatic brain injury (TBI) is known to cause short- and long-term synaptic changes in the brain, possibly underlying downstream cognitive impairments. Neurogranin (Ng) is a calcium-sensitive calmodulin (CaM)-binding protein essential for Ca2+/CaM-dependent kinase II (CaMKII) autophosphorylation (P-CaMKII) which modulates synaptic plasticity and is crucial to normal cognitive function. The overall hypothesis is that decreased Ng expression contributes to dysfunctional synaptic plasticity and associated anatomical and behavioral metrics after TBI. Therefore, increasing Ng expression after TBI will improve post-synaptic signaling and functional outcomes. We found that controlled cortical impact (CCI) lowers Ng expression with temporal and regional specificity and this occurs independently of post-synaptic loss. There were significant injury and sex-dependent alterations in the hippocampal synaptic expression of Ng and associated synaptic proteins such as phosphorylated Ng, CaMKII, P-CaMKII, and CaM up to 4 weeks post-CCI, demonstrating TBI alters hippocampal post-synaptic signaling. To investigate Ng’s role in the observed synaptic pathology, an adeno-associated viral vector (AAV) was developed to selectively increase hippocampal Ng expression by the 4-week time-point after CCI. We demonstrated that although there are limited effects of increasing Ng expression on downstream signaling protein expression, distinct, TBI-dependent effects on synaptic plasticity proteins were observed. Assessment of spatial learning and memory, as well as CA1 dendritic spine density and morphology, 4 weeks-post-injury also revealed a TBI-dependent effect of increased Ng. Although increasing Ng expression had limited effects on motor and cognitive behaviors, increased Ng demonstrated a TBI-dependent effect on the density of distinct hippocampal CA1 dendritic spine morphological sub-types. Finally, all-trans Retinoic Acid (ATRA) has been identified as a potential pharmacotherapeutic for increasing expression of synaptic plasticity proteins, such as Ng, and improving hippocampal learning and memory. ATRA treatment significantly recovered Ng synaptic protein expression 2 weeks after CCI. There was a limited therapeutic effect of daily ATRA treatment on motor and learning and memory outcomes. This study was also examined the effect of experimental TBI on RA signaling proteins, of which expression was unchanged 2 weeks after CCI. Altogether, this study was the first to investigate the role of Ng in hippocampal synaptic deficits in an experimental TBI model and furthered the field’s understanding of molecular mechanisms of cognitive dysfunction

Presenilin 1 increases association with synaptotagmin 1 during normal aging

Presenilin 1 (PS1), the catalytic component of gamma secretase, associates with synaptotagmin 1 (Syt-1). This interaction is decreased in the brains of patients with sporadic Alzheimer's disease. However, it remains unclear how this interaction changes during normal aging. Because aging is a risk factor for Alzheimer's disease, we sought to identify changes in PS1 and Syt-1 association during aging in primary neurons in vitro and mouse brain sections ex vivo. We also tested the effect of aging on the calcium dependence of the interaction by treating neurons aged in vitro with KCl. We found that PS1 and Syt-1 increase their association with age, an effect that is more robust in neuronal processes than cell bodies. Treatment with KCl triggered the interaction in both young and old neurons. Baseline calcium levels and calcium influx in response to KCl treatment were significantly higher in older neurons, which can partially explain the increase in PS1/Syt-1 binding with age. These results suggest a compensatory mechanism during normal aging to offset detrimental age-associated effects.status: publishe

Pubertal shifts in adrenal responsiveness to stress and adrenocorticotropic hormone in male rats

Studies have indicated significant pubertal-related differences in hormonal stress reactivity. We report here that prepubertal (30 days) male rats display a more protracted stress-induced corticosterone response than adults (70 days), despite showing relatively similar levels of adrenocorticotropic hormone (ACTH). Additionally, we show that adrenal expression of the ACTH receptor, melanocortin 2 receptor (Mc2r), is higher in prepubertal compared to adult animals, and that expression of melanocortin receptor accessory protein (Mrap), a molecule that chaperones MC2R to the cell surface, is greater in prepubertal males following stress. Given that these data suggest a pubertal shift in adrenal sensitivity to ACTH, we directly tested this possibility by injecting prepubertal and adult males with 6.25 or 9.375μg/kg of exogenous rat ACTH and measured their hormone levels 30 and 60min post-injection. As these doses resulted in different circulating levels of ACTH at these two ages, we performed regression analyses to assess the relationship between circulating ACTH and corticosterone concentrations. We found no difference between the ages in the correlation between ACTH and corticosterone levels at the 30min time point. However, 60min following the ACTH injection, we found prepubertal rats had significantly higher corticosterone concentrations at lower levels of ACTH compared to adults. These data suggest that prolonged exposure to ACTH leads to greater corticosterone responsiveness prior to puberty, and indicate that changes in adrenal sensitivity to ACTH may, in part, contribute to the protracted hormonal stress response in prepubertal rats

Pathogenic PS1 phosphorylation at Ser367

The high levels of serine (S) and threonine (T) residues within the Presenilin 1 (PS1) N-terminus and in the large hydrophilic loop region suggest that the enzymatic function of PS1/γ-secretase can be modulated by its ‘phosphorylated’ and ‘dephosphorylated’ states. However, the functional outcome of PS1 phosphorylation and its significance for Alzheimer’s disease (AD) pathogenesis is poorly understood. Here, comprehensive analysis using FRET-based imaging reveals that activity-driven and Protein Kinase A-mediated PS1 phosphorylation at three domains (domain 1: T74, domain 2: S310 and S313, domain 3: S365, S366, and S367), with S367 being critical, is responsible for the PS1 pathogenic ‘closed’ conformation, and resulting increase in the Aβ42/40 ratio. Moreover, we have established novel imaging assays for monitoring PS1 conformation in vivo, and report that PS1 phosphorylation induces the pathogenic conformational shift in the living mouse brain. These phosphorylation sites represent potential new targets for AD treatment. DOI: http://dx.doi.org/10.7554/eLife.19720.00

Exploring delay-based tcp congestion control

The thesis begins with a short review of TCP and new congestion control schemes in Chapter 2. Following this, chapter 3 explores the question of whether correlation between congestion and the delay signal of each flow on a link is really necessary for delay-based congestion control to function. It also explores the behaviour of the delay-based AIMD (DB-AIMD) algorithm in various network environments. Chapter 4 presents an experimental study into the effectiveness of a particular delay-based methodology for emptying network queues where congestion is detected. Finally, chapter 5 discussed some practical issues involved in how one measures RTT in practice for the purposes of congestion control

Additional file 1: of Identification of the novel activity-driven interaction between synaptotagmin 1 and presenilin 1 links calcium, synapse, and amyloid beta

Spectral FRET analysis of the GFP and RFP intensities. Primary neurons were transfected with GFP-PS1 (negative FRET control, n = 12 cells), RFP-GFP fusion (R-G, positive FRET control, n = 24) or GFP-PS1-RFP (PS1 conformation FRET probe, n = 10). The GFP was excited by argon laser at 488 nm wavelength, and the emission intensities of GFP and RFP within the 513 ± 10.57 nm and 598 ± 10.57 nm spectral bandwidth of the Metadector, respectively, were collected every 3 minutes for the duration of 33 minutes (middle and bottom graphs, respectively). The arrow indicates the time point of 50 mM KCl stimulation. No significant change in the GFP or RFP fluorescence emission intensity (no photobleaching), or the R/G ratio was observed in the G-PS1 and R-G transfected cells. The change in the R/G ratio after KCl stimulation was detected only in G-PS1-R transfected cells due to increased FRET efficiency/change in PS1 conformation. The black line shows mean ± SEM values. (TIF 1663 kb

Putative dendritic correlates of chronic traumatic encephalopathy: A preliminary quantitative Golgi exploration

Chronic traumatic encephalopathy (CTE) is a neurodegenerative disorder that is associated with repetitive head impacts. Neuropathologically, it is defined by the presence of perivascular hyperphosphorylated tau aggregates in cortical tissue (McKee et al., 2016, Acta Neuropathologica, 131, 75-86). Although many pathological and assumed clinical correlates of CTE have been well characterized, its effects on cortical dendritic arbors are still unknown. Here, we quantified dendrites and dendritic spines of supragranular pyramidal neurons in tissue from human frontal and occipital lobes, in 11 cases with (Mage = 79 ± 7 years) and 5 cases without (Mage = 76 ± 11 years) CTE. Tissue was stained with a modified rapid Golgi technique. Dendritic systems of 20 neurons per region in each brain (N = 640 neurons) were quantified using computer-assisted morphometry. One key finding was that CTE neurons exhibited increased variability and distributional changes across six of the eight dendritic system measures, presumably due to ongoing degeneration and compensatory reorganization of dendritic systems. However, despite heightened variation among CTE neurons, CTE cases exhibited lower mean values than Control cases in seven of the eight dendritic system measures. These dendritic alterations may represent a new pathological marker of CTE, and further examination of dendritic changes could contribute to both mechanistic and functional understandings of the disease

Pubertal shifts in adrenal responsiveness to stress and adrenocorticotropic hormone in male rats

Studies have indicated significant pubertal-related differences in hormonal stress reactivity. We report here that prepubertal (30d) male rats display a more protracted stress-induced corticosterone response than adults (70d), despite showing relatively similar levels of adrenocorticotropic hormone (ACTH). Additionally, we show that adrenal expression of the ACTH receptor, melanocortin 2 receptor (Mc2r), is higher in prepubertal compared to adult animals, and that expression of melanocortin receptor accessory protein (Mrap), a molecule that chaperones MC2R to the cell surface, is greater in prepubertal males following stress. Given that these data suggest a pubertal shift in adrenal sensitivity to ACTH, we directly tested this possibility by injecting prepubertal and adult males with 6.25 or 9.375 μg/kg of exogenous rat ACTH and measured their hormone levels 30 and 60 min post-injection. As these doses resulted in different circulating levels of ACTH at these two ages, we performed regression analyses to assess the relationship between circulating ACTH and corticosterone concentrations. We found no difference between the ages in the correlation between ACTH and corticosterone levels at the 30 min time point. However, 60 min following the ACTH injection, we found prepubertal rats had significantly higher corticosterone concentrations at lower levels of ACTH compared to adults. These data suggest that prolonged exposure to ACTH leads to greater corticosterone responsiveness prior to puberty, and indicate that changes in adrenal sensitivity to ACTH may, in part, contribute to the protracted hormonal stress response in prepubertal rats