Pacific Northwest National Laboratory has recently opened a shallow underground laboratory intended for measurement of low-concentration levels of radioactive isotopes in samples collected from the ...environment. The development of a low-background liquid scintillation counter is currently underway to further augment the measurement capabilities within this underground laboratory. Liquid scintillation counting is especially useful for measuring charged particle (e.g., β and α) emitting isotopes with no (or very weak) gamma-ray yields. The combination of high-efficiency detection of charged particle emission in a liquid scintillation cocktail coupled with the low-background environment of an appropriately designed shield located in a clean underground laboratory provides the opportunity for increased-sensitivity measurements of a range of isotopes. To take advantage of the 35m-water-equivalent overburden of the underground laboratory, a series of simulations have evaluated the scintillation counter's shield design requirements to assess the possible background rate achievable. This report presents the design and background evaluation for a shallow underground, low background liquid scintillation counter design for sample measurements.
•Graded-shielding can produce an ultra-low-background liquid scintillation counter.•Location in a shallow underground cleanroom further enhances background reduction.•A novel light collection design and selected low background materials are utilized.•The background is predicted to be 10–100 times below typical commercial systems.•Simulations tentatively predict a background rate of order 10 counts per day.
The Ultra-Low Background Liquid Scintillation Counter developed by Pacific Northwest National Laboratory will expand the application of liquid scintillation counting by enabling lower detection ...limits and smaller sample volumes. By reducing the overall count rate of the background environment approximately 2 orders of magnitude below that of commercially available systems, backgrounds on the order of tens of counts per day over an energy range of ~3–3600keV can be realized. Initial test results of the ULB LSC show promising results for ultra-low background detection with liquid scintillation counting.
•Observed background is within a factor of 2 of the predictions from simulation.•Background achieved is 2 orders of magnitude below commercially available systems.•Backgrounds are in tens of counts per day over an energy range of ~3– 3600keV.•Initial results show promise for ultra-low background detection with the ULB LSC.
Chronic pancreatitis (CP) is characterized by several disease-related complications and multiple etiological risk factors. Past studies of associations between complications and risk factors have ...mostly been limited to single complications or highly focused on single etiologies. Using an objective data-driven approach (cluster analysis), we characterized complication clusters and their associations with etiological risk factors in a large cohort of patients with CP.
This was a multicenter, cross-sectional study including 1,071 patients with CP from the Scandinavian and Baltic countries. Complications to CP were classified according to the M-ANNHEIM system, and treelet transform was used to derive complication clusters. Cluster complication frequencies were analyzed for their association with main etiological risk factors (smoking and alcohol).
The mean age of participants was 57 years and 66% were men. Alcohol (55%) and smoking (53%) were the most common etiological risk factors and seen in combination in 36% of patients. Cluster analysis identified 3 distinct complication clusters characterized by inflammation, fibrosis, and pancreatic insufficiencies. An independent association between inflammatory complications and alcoholic etiology was seen (odds ratio OR 2.00 95% CI confidence interval, 1.38-2.90, P < 0.001), whereas smoking was associated with fibrosis-related complications (OR 2.23 95% CI, 1.56-2.3.20, P < 0.001) and pancreatic insufficiencies (OR 1.42 95% CI, 1.00-2.01, P = 0.046).
Three distinctive clusters of complications to CP were identified. Their differing associations with alcoholic and smoking etiology indicate distinct underlying disease mechanisms.
Objectives: Chronic pancreatitis (CP) is a multifaceted disease associated with several risk factors and a complex clinical presentation. We established the Scandinavian Baltic Pancreatic Club (SBPC) ...Database to characterise and study the natural history of CP in a Northern European cohort. Here, we describe the design of the database and characteristics of the study cohort.
Methods: Nine centres from six different countries in the Scandinavian-Baltic region joined the database. Patients with definitive or probable CP (M-ANNHEIM diagnostic criteria) were included. Standardised case report forms were used to collect several assessment variables including disease aetiology, duration of CP, preceding acute pancreatitis, as well as symptoms, complications, and treatments. The clinical stage of CP was characterised according to M-ANNNHEIM. Yearly follow-up is planned for all patients.
Results: The study cohort comprised of 910 patients (608 men: 302 women; median age 58 (IQR: 48-67) years with definite 848 (93%) or probable CP 62 (7%). Nicotine (70%) and alcohol (59%) were the most frequent aetiologies and seen in combination in 44% of patients. A history of recurrent acute pancreatitis was seen in 49% prior to the development of CP. Pain (69%) and exocrine pancreatic insufficiency (68%) were the most common complications followed by diabetes (43%). Most patients (30%) were classified as clinical stage II (symptomatic CP with exocrine or endocrine insufficiency). Less than 10% of the patients had undergone pancreatic surgery.
Conclusion: The SBPC database provides a mean for future prospective, observational studies of CP in the Northern European continent.
Hippocampal enlargements are commonly reported after electroconvulsive therapy (ECT). To clarify mechanisms, we examined if ECT-induced hippocampal volume change relates to dose (number of ECT ...sessions and electrode placement) and acts as a biomarker of clinical outcome.
Longitudinal neuroimaging and clinical data from 10 independent sites participating in the Global ECT-Magnetic Resonance Imaging Research Collaboration (GEMRIC) were obtained for mega-analysis. Hippocampal volumes were extracted from structural magnetic resonance images, acquired before and after patients (n = 281) experiencing a major depressive episode completed an ECT treatment series using right unilateral and bilateral stimulation. Untreated nondepressed control subjects (n = 95) were scanned twice.
The linear component of hippocampal volume change was 0.28% (SE 0.08) per ECT session (p < .001). Volume change varied by electrode placement in the left hippocampus (bilateral, 3.3 ± 2.2%, d = 1.5; right unilateral, 1.6 ± 2.1%, d = 0.8; p < .0001) but not the right hippocampus (bilateral, 3.0 ± 1.7%, d = 1.8; right unilateral, 2.7 ± 2.0%, d = 1.4; p = .36). Volume change for electrode placement per ECT session varied similarly by hemisphere. Individuals with greater treatment-related volume increases had poorer outcomes (Montgomery–Åsberg Depression Rating Scale change –1.0 SE 0.35, per 1% volume increase, p = .005), although the effects were not significant after controlling for ECT number (slope –0.69 SE 0.38, p = .069).
The number of ECT sessions and electrode placement impacts the extent and laterality of hippocampal enlargement, but volume change is not positively associated with clinical outcome. The results suggest that the high efficacy of ECT is not explained by hippocampal enlargement, which alone might not serve as a viable biomarker for treatment outcome.
There is scarce information about risk factors for exocrine pancreas insufficiency (EPI) in chronic pancreatitis (CP), and how it associates with other complications. The aim of the present study was ...to examine risk factors for EPI and associations to procedures and other CP related complications in a large, Northern European cohort.
We retrieved cross-sectional data on demographics, status on EPI, aetiological risk factors for CP, CP related complications as well as surgical and endoscopic treatment from the Scandinavian Baltic Pancreatic Club Database. Associations were assessed by univariate and multivariate logistic regression analyses. Results are presented as odds ratios (OR) with 95% confidence intervals.
We included 1869 patients with probable or definitive CP in the study. Exocrine pancreas insufficiency was present in 849 (45.4%) of patients. In multivariate analyses, EPI associated with smoking aetiology (OR 1.47 (1.20–1.79), p < 0.001), and nutritional/metabolic aetiology (OR 0.52 (0.31–0.87), p = 0.01) to CP. Pancreatic or common bile duct stenting procedure and pancreatic resection were both associated with EPI (ORs 1.44 (1.15–1.80), p = 0.002 and 1.54 (1.02–2.33), p = 0.04, respectively). The presence of diabetes mellitus (OR 2.45 (1.92–3.15), p < 0.001), bile duct stenosis (OR 1.48 (1.09–2.00), p = 0.02) and underweight (2.05 (OR 1.40–3.02), p < 0.001) were all associated with presence of EPI.
Smoking, bile duct stenosis, previous stenting and resection procedures are all associated with EPI in patients with CP. Presence of EPI were also associated with malnutrition and diabetes mellitus. Hence, intensive nutritional surveillance is needed in these patients.
Electroconvulsive therapy (ECT) is associated with volumetric enlargements of corticolimbic brain regions. However, the pattern of whole-brain structural alterations following ECT remains unresolved. ...Here, we examined the longitudinal effects of ECT on global and local variations in gray matter, white matter, and ventricle volumes in patients with major depressive disorder as well as predictors of ECT-related clinical response.
Longitudinal magnetic resonance imaging and clinical data from the Global ECT-MRI Research Collaboration (GEMRIC) were used to investigate changes in white matter, gray matter, and ventricle volumes before and after ECT in 328 patients experiencing a major depressive episode. In addition, 95 nondepressed control subjects were scanned twice. We performed a mega-analysis of single subject data from 14 independent GEMRIC sites.
Volumetric increases occurred in 79 of 84 gray matter regions of interest. In total, the cortical volume increased by mean ± SD of 1.04 ± 1.03% (Cohen’s d = 1.01, p < .001) and the subcortical gray matter volume increased by 1.47 ± 1.05% (d = 1.40, p < .001) in patients. The subcortical gray matter increase was negatively associated with total ventricle volume (Spearman’s rank correlation ρ = −.44, p < .001), while total white matter volume remained unchanged (d = −0.05, p = .41). The changes were modulated by number of ECTs and mode of electrode placements. However, the gray matter volumetric enlargements were not associated with clinical outcome.
The findings suggest that ECT induces gray matter volumetric increases that are broadly distributed. However, gross volumetric increases of specific anatomically defined regions may not serve as feasible biomarkers of clinical response.
Pancreatic calcifications is a common finding in patients with chronic pancreatitis (CP), but the underlying pathophysiology is incompletely understood. Past studies for risk factors of ...calcifications have generally been focused on single parameters or limited by small sample sizes. The aim of this study was to explore several patient and disease characteristics and their associations with pancreatic calcifications in a large cohort of CP patients with diverse aetiological risk factors.
This was a multicentre, cross-sectional study including 1509 patients with CP. Patient and disease characteristics were compared for patients with calcifications (n = 912) vs. without calcifications (n = 597). Multivariable logistic regression was performed to assess the parameters independently associated with calcifications.
The mean age of patients was 53.9 ± 14.5 years and 1006 (67%) were men. The prevalence of calcifications was 60.4% in the overall patient cohort, but highly variable between patients with different aetiological risk factors (range: 2–69%). On multivariate analysis, alcoholic aetiology (OR 1.76 95% CI, 1.39–2.24; p < 0.001) and smoking aetiology (OR 1.77 95% CI, 1.39–2.26, p < 0.001) were positively associated with the presence of calcifications, while an autoimmune aetiology was negatively associated with calcifications (OR 0.15 95% CI, 0.08–0.27, p < 0.001). Patients with pancreatic calcifications were more likely to have undergone pancreatic duct stenting (OR 1.59 95%CI, 1.16–2.19, p = 0.004).
The presence of pancreatic calcifications is associated with diverse aetiological risk factors in patients with CP. This observation attest to the understanding of CP as a complex disease and may have implications for disease classification.
Pacific Northwest National Laboratory has recently opened a shallow underground laboratory intended for measurement of low-concentration levels of radioactive isotopes in samples collected from the ...environment. The development of a low-background liquid scintillation counter is currently underway to further augment the measurement capabilities within this underground laboratory. Liquid scintillation counting is especially useful for measuring charged particle (e.g., \(\beta\), \(\alpha\)) emitting isotopes with no (or very weak) gamma-ray yields. The combination of high-efficiency detection of charged particle emission in a liquid scintillation cocktail coupled with the low-background environment of an appropriately-designed shield located in a clean underground laboratory provides the opportunity for increased-sensitivity measurements of a range of isotopes. To take advantage of the 35 meters-water-equivalent overburden of the underground laboratory, a series of simulations have evaluated the scintillation counter's shield design requirements to assess the possible background rate achievable. This report presents the design and background evaluation for a shallow underground, low background liquid scintillation counter design for sample measurements.
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