Purpose: The cause of choledochal (cystic or fusiform) malformation is not known.A favoured hypothesis suggests that abnormal reflux of activated pancreatic secretions via a common pancreatobiliary channelmay initiate...Purpose: The cause of choledochal (cystic or fusiform) malformation is not known.A favoured hypothesis suggests that abnormal reflux of activated pancreatic secretions via a common pancreatobiliary channelmay initiate mucosal injury and mural weakness leading to bile duct dilatation, at normal intraduct pressures.However, bile duct pressures in both normal or disease states are not known in such children.Methods: Intraoperative choledochal pressure (CP) measurements were made before any other manipulation.Bile was cultured and its amylase content measured.Biochemical liver function (bilirubin, aspartate aminotransferase, γ-glutamyl transpeptidase, and alkaline phosphatase)was measured.Datawere quoted as median (interquartile range).Statistical tests were parametric, where appropriate, and P =.05 was regarded as significant.Results: Twenty-five children (age 2.5 [1.25-5.91] years) with choledochal (cystic [n = 13] and fusiform [n = 12]) malformation coming to surgery were studied.Median CP was 13 (8.5-17)-mm Hg.Median bile amylase was 6722 (241-18,000) IU/L.Choledochal pressure inversely correlated with bile amylase (r = -0.60, P =.001), serum aspartate aminotransferase (r = 0.46, P =.01), and log γ-glutamyl transpeptidase (r = 0.4, P =.04) but not with bilirubin (P =.11), alkaline phosphatase (P =.20), or age (P =.11).No difference in CP, bile amylase, or liver biochemistry could be identified between the 2 biliary phenotypes.All bile cultures were sterile.Conclusions: Increased CP is inversely related to the level of bile amylase (and hence degree of the functional common channel).This suggests that obstructive stenosis at the level of the pancreato-biliary junction (but not the ampulla) may be a causal factor in a proportion of choledochal malformations.展开更多
Based on the data from the Medium-Energy Proton and Electron Detector （MEPED） onboard NOAA-17, 141 anomalies of a Chinese Sun-Synchronous satellite （SSO-X） that occurred between 02/01/2010 and 09/31/2012 were stud...Based on the data from the Medium-Energy Proton and Electron Detector （MEPED） onboard NOAA-17, 141 anomalies of a Chinese Sun-Synchronous satellite （SSO-X） that occurred between 02/01/2010 and 09/31/2012 were studied statistically. About 26 out of the 52 anomalies that occurred outside the South Atlantic Anomaly （SAA） were accompanied by energetic electron storms. Superposed Epoch Analysis （SEA） was used to analyze the properties of the anomalies and the dynamics of the space environments during these 26 events. Then, a Monte Carlo method was utilized to simulate the electron deposition and the interactions of the injected electrons with an aluminum shield and polyethylene dielectric. The average, median, and 75tb percentile values of the maximum electric field strength inside the dielectric were calculated. The results showed the tbl- lowing. （1） SSO-X anomalies are more likely to occur within the SAA, as 89 out of 141 anomalies （63%） occurred there. （2） Twenty-six of the anomalies that occurred outside the SAA during energetic electron storms were located near the outer boundaries of the outer radiation belts, and these were more frequent in the Southern Hemisphere than in the Northern Hemi- sphere. （3） Electron flux enhancements occurred around the failure time at all energy levels but were more profound in the lower energy channels. The maximum fluxes of electrons 〉30 keV, 〉100 keV, and 〉300 keV were 106, 3.5x10s, and 1.2×10^6 cm 2 s^-1 · sr ^-1, respectively. （4） The average, median, and 75th percentile values of the maximum electric field strengths inside the dielectric for the aforementioned 26 events remained in the range from 106 to 107 V/m for long time periods, which sug- gests that the ＇potential hazards＇ of internal discharges cause SSO-X anomalies. The above results can provide useful infor- mation for the design and protection of sun-synchronous spacecraft.展开更多
文摘Purpose: The cause of choledochal (cystic or fusiform) malformation is not known.A favoured hypothesis suggests that abnormal reflux of activated pancreatic secretions via a common pancreatobiliary channelmay initiate mucosal injury and mural weakness leading to bile duct dilatation, at normal intraduct pressures.However, bile duct pressures in both normal or disease states are not known in such children.Methods: Intraoperative choledochal pressure (CP) measurements were made before any other manipulation.Bile was cultured and its amylase content measured.Biochemical liver function (bilirubin, aspartate aminotransferase, γ-glutamyl transpeptidase, and alkaline phosphatase)was measured.Datawere quoted as median (interquartile range).Statistical tests were parametric, where appropriate, and P =.05 was regarded as significant.Results: Twenty-five children (age 2.5 [1.25-5.91] years) with choledochal (cystic [n = 13] and fusiform [n = 12]) malformation coming to surgery were studied.Median CP was 13 (8.5-17)-mm Hg.Median bile amylase was 6722 (241-18,000) IU/L.Choledochal pressure inversely correlated with bile amylase (r = -0.60, P =.001), serum aspartate aminotransferase (r = 0.46, P =.01), and log γ-glutamyl transpeptidase (r = 0.4, P =.04) but not with bilirubin (P =.11), alkaline phosphatase (P =.20), or age (P =.11).No difference in CP, bile amylase, or liver biochemistry could be identified between the 2 biliary phenotypes.All bile cultures were sterile.Conclusions: Increased CP is inversely related to the level of bile amylase (and hence degree of the functional common channel).This suggests that obstructive stenosis at the level of the pancreato-biliary junction (but not the ampulla) may be a causal factor in a proportion of choledochal malformations.
基金supported by the National Natural Science Foundation of China(Grant No.41421003)the Major Project of Chinese National Programs for Fundamental Research and Development(Grant No.2012CB825603)
文摘Based on the data from the Medium-Energy Proton and Electron Detector （MEPED） onboard NOAA-17, 141 anomalies of a Chinese Sun-Synchronous satellite （SSO-X） that occurred between 02/01/2010 and 09/31/2012 were studied statistically. About 26 out of the 52 anomalies that occurred outside the South Atlantic Anomaly （SAA） were accompanied by energetic electron storms. Superposed Epoch Analysis （SEA） was used to analyze the properties of the anomalies and the dynamics of the space environments during these 26 events. Then, a Monte Carlo method was utilized to simulate the electron deposition and the interactions of the injected electrons with an aluminum shield and polyethylene dielectric. The average, median, and 75tb percentile values of the maximum electric field strength inside the dielectric were calculated. The results showed the tbl- lowing. （1） SSO-X anomalies are more likely to occur within the SAA, as 89 out of 141 anomalies （63%） occurred there. （2） Twenty-six of the anomalies that occurred outside the SAA during energetic electron storms were located near the outer boundaries of the outer radiation belts, and these were more frequent in the Southern Hemisphere than in the Northern Hemi- sphere. （3） Electron flux enhancements occurred around the failure time at all energy levels but were more profound in the lower energy channels. The maximum fluxes of electrons 〉30 keV, 〉100 keV, and 〉300 keV were 106, 3.5x10s, and 1.2×10^6 cm 2 s^-1 · sr ^-1, respectively. （4） The average, median, and 75th percentile values of the maximum electric field strengths inside the dielectric for the aforementioned 26 events remained in the range from 106 to 107 V/m for long time periods, which sug- gests that the ＇potential hazards＇ of internal discharges cause SSO-X anomalies. The above results can provide useful infor- mation for the design and protection of sun-synchronous spacecraft.
