| 61. |
- Mattsson, Karin, et al.
(författare)
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Translocation of 40 nm diameter nanowires through the intestinal epithelium of Daphnia magna
- 2016
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Ingår i: Nanotoxicology. - : Informa UK Limited. - 1743-5390 .- 1743-5404. ; 10:8, s. 1160-1167
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Tidskriftsartikel (refereegranskat)abstract
- Nanowires (NWs) have unique electrical and optical properties of value for many applications including lighting, sensing, and energy harnessing. Consumer products containing NWs increase the risk of NWs being released in the environment, especially into aquatic ecosystems through sewage systems. Daphnia magna is a common, cosmopolitan freshwater organism sensitive to toxicity tests and represents a likely entry point for nanoparticles into food webs of aquatic ecosystems. Here we have evaluated the effect of NW diameter on the gut penetrance of NWs in Daphnia magna. The animals were exposed to NWs of two diameters (40 and 80 nm) and similar length (3.6 and 3.8 μm, respectively) suspended in water. In order to locate the NWs in Daphnia, the NWs were designed to comprise one inherently fluorescent segment of gallium indium phosphide (GaInP) flanked by a gallium phosphide (GaP) segment. Daphnia mortality was assessed directly after 24 h of exposure and 7 days after exposure. Translocation of NWs across the intestinal epithelium was investigated using confocal fluorescence microscopy directly after 24 h of exposure and was observed in 89% of Daphnia exposed to 40 nm NWs and in 11% of Daphnia exposed to 80 nm NWs. A high degree of fragmentation was observed for NWs of both diameters after ingestion by the Daphnia, although 40 nm NWs were fragmented to a greater extent, which could possibly facilitate translocation across the intestinal epithelium. Our results show that the feeding behavior of animals may enhance the ability of NWs to penetrate biological barriers and that penetrance is governed by the NW diameter.
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| 62. |
- McKibbin, Sarah R., et al.
(författare)
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Operando Surface Characterization of InP Nanowire p-n Junctions
- 2020
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Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 20:2, s. 887-895
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Tidskriftsartikel (refereegranskat)abstract
- We present an in-depth analysis of the surface band alignment and local potential distribution of InP nanowires containing a p-n junction using scanning probe and photoelectron microscopy techniques. The depletion region is localized to a 15 nm thin surface region by scanning tunneling spectroscopy and an electronic shift of up to 0.5 eV between the n- A nd p-doped nanowire segments was observed and confirmed by Kelvin probe force microscopy. Scanning photoelectron microscopy then allowed us to measure the intrinsic chemical shift of the In 3d, In 4d, and P 2p core level spectra along the nanowire and the effect of operating the nanowire diode in forward and reverse bias on these shifts. Thanks to the high-resolution techniques utilized, we observe fluctuations in the potential and chemical energy of the surface along the nanowire in great detail, exposing the sensitive nature of nanodevices to small scale structural variations.
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| 63. |
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| 64. |
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| 65. |
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| 66. |
- Muller, Christophe A., et al.
(författare)
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Corticosteroid-binding globulin: A possible early predictor of infection in acute necrotizing pancreatitis
- 2007
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Ingår i: Scandinavian Journal of Gastroenterology. - : Informa UK Limited. - 1502-7708 .- 0036-5521. ; 42:11, s. 1354-1361
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Tidskriftsartikel (refereegranskat)abstract
- Objective. Infected pancreatic necrosis is the main cause of death in patients with acute pancreatitis, and therefore its early prediction is of utmost importance. Endogenous cortisol metabolism plays a basic role both in the course of acute pancreatitis and in the process of infection. The purpose of this study was to analyze corticosteroid-binding globulin (CBG), total cortisol, calculated free cortisol and adrenocorticotropic hormone as potential early predictors in order to differentiate between infected pancreatic necrosis and sterile pancreatic necrosis in patients with acute pancreatitis. Material and methods. Serum levels of CBG, total cortisol, calculated free cortisol, and plasma levels of adrenocorticotropic hormone were determined in 109 consecutive patients with acute pancreatitis. C-reactive protein was measured as the control parameter. Thirty-five patients developed necrotizing pancreatitis and 10 developed infection of the necrosis. Blood was monitored for 6 days after the onset of pain; 30 healthy individuals served as controls. Results. Of all parameters only CBG showed a significant difference ( p = 0.0318) in its peak levels measured in the first 48 h in patients with sterile (26.5 mu g/ml, range 21.3-34.7) and infected (16.0 mu g/ml, range 15.2-25.0) necrosis at a cut-off level of 16.8 mu g/ml. That difference was further preserved for the first 6 days after onset of pain. Conclusions. In our group of patients, a decreased CBG level below 16.8 g/ml within the initial 48 h of acute pancreatitis was an early predictor of later infected pancreatic necrosis, with a positive predictive value of 100% and a negative predictive value of 87.5%.
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| 67. |
- Muller, C. A., et al.
(författare)
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Dexamethasone affects inflammation but not trypsinogen activation in experimental acute pancreatitis
- 2008
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Ingår i: European Surgical Research. - : S. Karger AG. - 0014-312X .- 1421-9921. ; 40:4, s. 317-324
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Tidskriftsartikel (refereegranskat)abstract
- Background/Aims: Trypsinogen activation and inflammation are early events in acute pancreatitis. This experimental study aimed to show the effects of dexamethasone on them. Methods: Cerulein and taurocholate pancreatitis were induced in 2 groups of 12 Wistar rats each. Six animals per group were injected with dexamethasone 1 h prior to the induction of acute pancreatitis. Amylase, phospholipase A2, TNF-alpha, IL-6, IL-10, alpha 2-antiplasmin in plasma and trypsinogen activation peptide (TAP) in urine were measured in healthy rats, then 0.5 and 6 h after pancreatitis induction. A severity score based on edema, necrosis and ascites was calculated at 6 h. TNF-alpha, IL-6 and IL-10 were measured 0.5 h after laparotomy in a control sham-operated group of 6 rats. Results: Inflammatory markers increased early in the course of both mild and severe acute pancreatitis and were significantly lowered by dexamethasone. The severity score was higher in taurocholate than in cerulein pancreatitis. It was significantly decreased by dexamethasone only in rats with mild pancreatitis. TAP remained unchanged in mild pancreatitis compared to healthy animals but increased late in the course of taurocholate pancreatitis. Trypsinogen activation was not affected by dexamethasone at all. Conclusion: Inflammation occurred earlier than the increase in urinary TAP in severe pancreatitis in rats. Dexamethasone inhibited inflammation but had no influence on TAP levels in experimental mild and severe acute pancreatitis. Copyright (C) 2008 S. Karger AG, Basel.
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| 68. |
- Müller, C A, et al.
(författare)
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Serum levels of procarboxypeptidase B and its activation peptide in patients with acute pancreatitis and non-pancreatic diseases
- 2002
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Ingår i: Gut. - : BMJ. - 1468-3288 .- 0017-5749. ; 51:2, s. 229-235
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Tidskriftsartikel (refereegranskat)abstract
- Background: Carboxypeptidase B from the pancreatic gland may exist in three different molecular and immunoreactive forms: the proenzyme, the active enzyme, and the activation peptide. Aims: To investigate levels of procarboxypeptidase B (proCAPB) and its activation peptide in serum in acute pancreatitis to test the accuracy of these two variables as markers for the diagnosis of acute pancreatitis and for prediction of pancreatic necrosis. To elucidate whether leakage of proenzymes and activation of proenzymes reflect two different pathophysiological events in acute pancreatitis. Methods: Sera from patients with acute pancreatitis (n=85) and acute abdominal pain of non-pancreatic origin (n=53) were analysed for proCAPB and its activation peptide. Patients with pancreatitis were divided into necrotising (n=33) and oedematous attacks (n=52) using contrast enhanced computed tomography. Accuracy was determined using receiver operating characteristic curve analysis. Results: Immunoreactive carboxypeptidase B activation peptide (ir-CAPAP) concentration in serum on admission was 0.7 nmol/l (0-18.1) in patients with oedematous pancreatitis compared with 5.8 nmol/l (1.9-34) in patients with later development of pancreatic necrosis. Elevated levels of the activation peptide on admission correlated with an accuracy of 92% to later development of pancreatic necrosis. Ir-proCAPB concentration in serum on admission was 16.0 nmol/l (1.4-50.5) in all patients with acute pancreatitis versus 0.3 nmol/l (0-3.6) in patients with non-pancreatic acute abdominal disorders. Cases with oedematous pancreatitis had ir-proCAPB levels of 15.4 nmol/l (1.4-50.5) versus 19.1 nmol/l (2.7-36.1) in cases with later development of pancreatic necrosis. Measurement of the proenzyme can thus be useful for the diagnosis of acute pancreatitis (accuracy 99%) but levels did not correlate with later development of pancreatic necrosis (accuracy 56%). Conclusion: Leakage of proenzymes occurs in acute pancreatitis, irrespective of severity, while development of pancreatic necrosis occurs only when there is activation of the proenzymes.
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| 69. |
- Muller, CA, et al.
(författare)
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A study on the activation peptide released from procarboxypeptidase B (CAPAP) and anionic trypsinogen in patients with acute abdominal disorders of non-pancreatic origin
- 2003
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Ingår i: Pancreatology. - : Elsevier BV. - 1424-3903. ; 3:2, s. 149-155
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Tidskriftsartikel (refereegranskat)abstract
- Background: The activation peptide released from procarboxypeptidase B, CAPAP, is a marker of the activation of pancreatic enzymes in acute pancreatitis while anionic trypsinogen (AT) levels in urine relate to leakage of unactivated proenzymes. Data on these markers in patients suffering from severe acute abdominal disorders of nonpancreatic origin are lacking. Purpose: To examine levels of CAPAP and AT in serum and urine from patients with severe acute abdominal disorders of non-pancreatic origin in order to better define the diagnostic specificity of these two markers in severe acute pancreatitis in relation to other acute intra-abdominal disorders. Subjects and Methods: The study included 54 patients with severe acute abdominal disorders of non-pancreatic origin with an APACHE II score >3. Immunoreactive CAPAP (irCAPAP) and immunoreactive AT (irAT) were measured in serum and urine using specific immunoassays. Results: In urine, irCAPAP levels were mildly increased (>2 nmol/l) in 13% of the patients with severe acute abdominal diseases of non-pancreatic origin, but on no occasion did the increase approach the cutoff levels described for severe acute pancreatitis (>100 nmol/l). However, irAT levels in serum and urine were increased (>50 mug/l) in 54% of the cases. Conclusion: Contrary to what is found for irAT, patients with acute abdominal pain of non-pancreatic origin rarely have markedly increased levels of irCAPAP in serum and urine. Copyright (C) 2003 S. Karger AG, Basel and IAP.
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| 70. |
- Muller, Christophe, et al.
(författare)
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Role of endogenous glucocorticoid metabolism in human acute pancreatitis*
- 2006
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Ingår i: Critical Care Medicine. - 1530-0293. ; 34:4, s. 1060-1066
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Tidskriftsartikel (refereegranskat)abstract
- Objective: This study aimed to observe how levels of total cortisol, calculated free cortisol, corticosteroid-binding globulin, and adrenocorticotropic hormone change during the early course of human acute pancreatitis and to describe how these changes affect the development of pancreatic necrosis. Design and Patients: In a total of 109 consecutive patients with acute pancreatitis (74 with edematous pancreatitis, 35 with necrotizing pancreatitis), serial daily blood monitoring of total and free cortisol, adrenocorticotropic hormone, and corticosteroid-binding globulin was done after hospital admission, up to day 6 after the onset of pain; 30 healthy individuals served as controls. Measurements. Corticosteroid-binding globulin and total cortisol were measured by immunoassays, and free cortisol was calculated according to Coolens et al. The adrenocorticotropic hormone was measured with an enzyme-linked immunoassay. Results, Initially, highly elevated levels of calculated free cortisol (median, 86.2 ng/mL; quartile ranges, 50.6-106.7 ng/mL) and total cortisol (41.2 mu g/dL, 30.4-51.1 mu g/dL) and depressed levels of adrenocarticotropic hormone (0.2 pg/mL, 0.1-2.0 pg/mL) and corticosteroid-binding globulin (30.6 mu g/mL, 24.1-35.5 mu g/mL) were observed. Further, daily measurements revealed increasing adrenocorticotropic hormone levels, whereas cortisol levels decreased. Conclusions: Although an increase in adrenocorticotropic hormone levels is suggested to increase corresponding cortisol levels, cortisol levels decreased during the development of necrotizing acute pancreatitis. This phenomenon, along with the continuously decreasing corticosteroid-binding globulin levels, brings up the hypothesis of a relative adrenal insufficiency, which favors acinar cell apoptosis and hence may trigger the development of necrosis in the initial vulnerable phase of acute pancreatitis.
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