Usefulness of serum lipase for early diagnosis of post-endoscopic retrograde cholangiopancreatography pancreatitis

BACKGROUND Post-endoscopic retrograde cholangiopancreatography(ERCP)pancreatitis(PEP)is new onset acute pancreatitis after ERCP.This complication is sometimes fatal.As such,PEP should be diagnosed early so that therapeutic interventions can be carried out.Serum lipase(s-Lip)is useful for diagnosing acute pancreatitis.However,its usefulness for diagnosing PEP has not been sufficiently investigated.AIM This study aimed to retrospectively examine the usefulness of s-Lip for the early diagnosis of PEP.METHODS We retrospectively examined 4192 patients who underwent ERCP at our two hospitals over the last 5 years.The primary outcomes were a comparison of the areas under the receiver operating characteristic(ROC)curves(AUCs)of s-Lip and serum amylase(s-Amy),s-Lip and s-Amy cutoff values based on the presence or absence of PEP in the early stage after ERCP via ROC curves,and the diagnostic properties[sensitivities,specificities,positive predictive values(PPV),and negative predictive value(NPV)]of these cutoff values for PEP diagnosis.RESULTS Based on the eligibility and exclusion criteria,804 cases were registered.Over the entire course,PEP occurred in 78 patients(9.7%).It occurred in the early stage after ERCP in 40 patients(51.3%)and in the late stage after ERCP in 38 patients(48.7%).The AUCs were 0.908 for s-Lip[95%confidence interval(CI):0.880-0.940,P<0.001]and 0.880 for s-Amy(95%CI:0.846-0.915,P<0.001),indicating both are useful for early diagnosis.By comparing the AUCs,s-Lip was found to be significantly more useful for the early diagnosis of PEP than s-Amy(P=0.023).The optimal cutoff values calculated from the ROC curves were 342 U/L for s-Lip(sensitivity,0.859;specificity,0.867;PPV,0.405;NPV,0.981)and 171 U/L for s-Amy(sensitivity,0.859;specificity,0.763;PPV,0.277;NPV,0.979).CONCLUSION S-Lip was significantly more useful for the early diagnosis of PEP.Measuring s-Lip after ERCP could help diagnose PEP earlier;hence,therapeutic interventions can be provided earlier.

Ocean Mixing with Lead-Dependent Subgrid Scale Brine Rejection Parameterization in a Climate Model

Sea ice thickness is highly spatially variable and can cause uneven ocean heat and salt flux on subgrid scales in climate models.Previous studies have demonstrated improvements in ocean mixing simulation using parameterization schemes that distribute brine rejection directly in the upper ocean mixed layer.In this study,idealized ocean model experiments were conducted to examine modeled ocean mixing errors as a function of the lead fraction in a climate model grid.When the lead is resolved by the grid,the added salt at the sea surface will sink to the base of the mixed layer and then spread horizontally.When averaged at a climate-model grid size,this vertical distribution of added salt is lead-fraction dependent.When the lead is unresolved,the model errors were systematic leading to greater surface salinity and deeper mixed-layer depth(MLD).An empirical function was developed to revise the added-salt-related parameter n from being fixed to lead-fraction dependent.Application of this new scheme in a climate model showed significant improvement in modeled wintertime salinity and MLD as compared to series of CTD data sets in 1997/1998 and 2006/2007.The results showed the most evident improvement in modeled MLD in the Arctic Basin,similar to that using a fixed n=5,as recommended by the previous Arctic regional model study,in which the parameter n obtained is close to 5 due to the small lead fraction in the Arctic Basin in winter.

Sensitivity study of subgrid scale ocean mixing under sea ice using a two-column ocean grid in climate model CESM

Brine drainage from sea ice formation plays a critical role in ocean mixing and seasonal variations of halocline in polar oceans. The horizontal scale of brine drainage and its induced convection is much smaller than a climate model grid and a model tends to produce false ocean mixing when brine drainage is averaged over a grid cell. A two-column ocean grid （TCOG） scheme was implemented in the Community Earth System Model （CESM） using coupled sea ice-ocean model setting to explicitly solve the different vertical mixing in the two sub- columns of one model grid with and without brine rejection. The fraction of grid with brine rejection was tested to be equal to the lead fraction or a small constant number in a series of sensitivity model runs forced by the same atmospheric data from 1978 to 2009. The model results were compared to observations from 29 ice tethered profilers （ITP） in the Arctic Ocean Basin from 2004 to 2009. Compared with the control run using a regular ocean grid, the TCOG simulations showed consistent reduction of model errors in salinity and mixed layer depth （MLD）. The model using a small constant fraction grid for brine rejection was found to produce the best model comparison with observations, indicating that the horizontal scale of the brine drainage is very small compared to the sea ice cover and even smaller than the lead fraction. Comparable to models using brine rejection parameterization schemes, TCOG achieved more improvements in salinity but similar in MLD.