Micelle-based fluorogenic sensing of trypsin: a sensitive method in pancreatic disease diagnosis.

Protamine-mediated micellar aggregates, featuring an AIE-based fluorescent sensor, facilitate efficient detection of trypsin activity. This method enables the detection of trypsin at exceptionally low concentrations (0.01-0.1 µg mL-1) in urine, demonstrating its potential for early clinical diagnosis of trypsin-related pancreatic diseases.

Impact of renal dysfunction on the diagnosis of acute pancreatitis using urinary trypsinogen-2: A retrospective study.

AIM: Early diagnosis of acute pancreatitis is crucial, and urinary trypsinogen has been recently reported as a useful biomarker for diagnosing acute pancreatitis. We aimed to evaluate the impact of renal dysfunction on the diagnostic performance of urinary trypsinogen-2 for acute pancreatitis. METHODS: We conducted a retrospective study using the clinical data of patients who visited the Department of Emergency and Critical Care at the University of Tokyo Hospital between 1 October, 2021, and 30 June, 2022. Patients with available data on qualitative urinary trypsinogen-2 levels were identified. We compared the urinary trypsinogen-2 levels among patients who were clinically diagnosed with acute pancreatitis. We further stratified the patients according to renal function parameters, such as serum creatinine level, blood urea nitrogen level, and estimated glomerular filtration rate, and evaluated the performance of urinary trypsinogen-2 as a biomarker for acute pancreatitis. RESULTS: Within 9 months, 35 patients were identified. Of them, 22 patients showed positive results and 13 showed negative results on the urinary trypsinogen-2 test. The sensitivity, specificity, positive predictive value, and negative predictive value were 0.80, 0.40, 0.18, and 0.92, respectively. Based on the blood urea nitrogen level and estimated glomerular filtration rate, the prevalence of false-positive results was significantly higher in patients with reduced renal function than in those with normal renal function. CONCLUSION: In patients with reduced renal function, the urinary trypsinogen-2 qualitative test results might be interpreted with caution when used for diagnosing acute pancreatitis.

A Paper-Based Near-Infrared Optical Biosensor for Quantitative Detection of Protease Activity Using Peptide-Encapsulated SWCNTs.

A protease is an enzyme that catalyzes proteolysis of proteins into smaller polypeptides or single amino acids. As crucial elements in many biological processes, proteases have been shown to be informative biomarkers for several pathological conditions in humans, animals, and plants. Therefore, fast, reliable, and cost-effective protease biosensors suitable for point-of-care (POC) sensing may aid in diagnostics, treatment, and drug discovery for various diseases. This work presents an affordable and simple paper-based dipstick biosensor that utilizes peptide-encapsulated single-wall carbon nanotubes (SWCNTs) for protease detection. Upon enzymatic digestion of the peptide, a significant drop in the photoluminescence (PL) of the SWCNTs was detected. As the emitted PL is in the near-infrared region, the developed biosensor has a good signal to noise ratio in biological fluids. One of the diseases associated with abnormal protease activity is pancreatitis. In acute pancreatitis, trypsin concentration could reach up to 84 µg/mL in the urine. For proof of concept, we demonstrate the feasibility of the proposed biosensor for the detection of the abnormal levels of trypsin activity in urine samples.

Urinary trypsinogen-2 level and local complications of acute pancreatitis.

BACKGROUND AND AIM: Local complications of acute pancreatitis (AP) carry risks of morbidity/mortality. This study aimed to assess whether urinary trypsinogen-2 levels and Bedside Index for Severity in Acute Pancreatitis (BISAP) score on admission predicted subsequent local complications. METHODS: One hundred and forty-four consecutive patients with AP were prospectively followed till 6 months after discharge. Urinary trypsinogen-2 levels were measured within 24 h of admission. Local complications (acute peripancreatic fluid collection, acute necrotic collection, pseudocyst, and walled-off necrosis) were diagnosed by abdominal computed tomography. Cut-off for trypsinogen-2 level was assessed using receiver operating characteristic curve, and predictors of local complications were analyzed by logistic regression. RESULTS: Thirty-seven (25.7%) patients developed local complications. Urinary trypsinogen-2 levels were significantly higher in patients with local complications compared with those without local complications (median [interquartile range], 3210 [620-9764.4] µg/L vs 627.3 [72.3-5895] µg/L, P = 0.006). Urinary trypsinogen-2 significantly outperformed BISAP score in predicting local complications (area under the receiver operating characteristic curve 0.65 [95% CI: 0.55-0.75] vs 0.48 [95% CI: 0.38-0.58], P = 0.005). At the optimal cut-off of 500 µg/L, the sensitivity, specificity, positive predictive value, and negative predictive value of trypsinogen-2 level were 78.4%, 45.8%, 33.3%, and 86.0%, respectively. Urinary trypsinogen-2 level > 500 µg/L was an independent predictor of local complications (adjusted odds ratio, 3.72; 95% CI: 1.42-9.76; P = 0.007). By contrast, BISAP score ≥ 3 and pleural effusion predicted organ failure but not local complications. CONCLUSION: In a prospective cohort, urinary trypsinogen-2 level > 500 µg/L independently predicted local complications of AP.

Usefulness of urinary trypsinogen-2 and trypsinogen activation peptide in acute pancreatitis: A multicenter study in Japan.

BACKGROUND: Rapid urinary trypsinogen-2 dipstick test and levels of urinary trypsinogen-2 and trypsinogen activation peptide (TAP) concentration have been reported as prognostic markers for the diagnosis of acute pancreatitis. AIM: To reconfirm the validity of all these markers in the diagnosis of acute pancreatitis by undertaking a multi-center study in Japan. METHODS: Patients with acute abdominal pain were recruited from 17 medical institutions in Japan from April 2009 to December 2012. Urinary and serum samples were collected twice, at enrollment and on the following day for measuring target markers. The diagnosis and severity assessment of acute pancreatitis were assessed based on prognostic factors and computed tomography (CT) Grade of the Japanese Ministry of Health, Labour, and Welfare criteria. RESULTS: A total of 94 patients were enrolled during the study period. The trypsinogen-2 dipstick test was positive in 57 of 78 patients with acute pancreatitis (sensitivity, 73.1%) and in 6 of 16 patients with abdominal pain but without any evidence of acute pancreatitis (specificity, 62.5%). The area under the curve (AUC) score of urinary trypsinogen-2 according to prognostic factors was 0.704, which was highest in all parameter. The AUC scores of urinary trypsinogen-2 and TAP according to CT Grade were 0.701 and 0.692, respectively, which shows higher than other pancreatic enzymes. The levels of urinary trypsinogen-2 and TAP were significantly higher in patients with extended extra-pancreatic inflammation as evaluated by CT Grade. CONCLUSION: We reconfirmed urinary trypsinogen-2 dipstick test is useful as a marker for the diagnosis of acute pancreatitis. Urinary trypsinogen-2 and TAP may be considered as useful markers to determine extra-pancreatic inflammation in acute pancreatitis.

A fluorometric sensing method for sensitive detection of trypsin and its inhibitor based on gold nanoclusters and gold nanoparticles.

In this work, a facile, label-free, and sensitive fluorometric strategy for detection of trypsin and its inhibitor was established on the basis of the fluorescence resonance energy transfer (FRET) between mercaptoundecanoic acid functionalized gold nanoclusters (AuNCs) and gold nanoparticles (AuNPs) via protamine as a bridge. Protamine can trigger the aggregation of AuNPs and link AuNCs with aggregated AuNPs through electrostatic interaction. Compared with monodisperse AuNPs, the UV-vis absorption band of aggregated AuNPs overlapped considerably with the emission spectrum of AuNCs. Thus, the fluorescence of AuNCs was obviously quenched by the aggregated AuNPs through FRET. In the presence of trypsin, protamine was hydrolyzed into small fragments, leading to the deaggregation of AuNPs and breaking of the short distance between AuNPs and AuNCs, so the FRET process was inhibited, and the fluorescence of AuNCs was recovered. The increase in the fluorescence intensity of AuNCs was directly related to the amount of trypsin. Hence trypsin can be determined on the basis of the variation of fluorescence intensity, with a linear range of 5-5000 ng mL-1 and a detection limit of 1.9 ng mL-1. In addition, this system was used for the detection of trypsin inhibitor by application of the inhibitor isolated from soybean as a model. The sensing method was applied for trypsin detection in human urine and commercial multienzyme tablet samples with satisfactory results. Graphical abstract ᅟ.

Ultrasensitive detection of trypsin activity and inhibitor screening based on the electron transfer between phosphorescence copper nanocluster and cytochrome c.

Trypsin, as one of important proteases, is specific for catalyzing the hydrolysis of peptide and ester bonds containing lysine and arginine residues at the C-terminus. The level of trypsin in biological fluids can serve as a reliable and specific diagnostic biomarker for pancreatic function and its pathological changes. Herein, we demonstrate the application of phosphorescent Cu NCs for trypsin detection for the first time depending on the electron transfer between Cu NCs and cyt c. Cyt c and Cu NCs were selected as the quencher and the fluorophore, respectively. Cu NCs could bind to the positively charged cyt c through electrostatic and hydrophobic interactions, and the phosphorescence of Cu NCs was efficiently quenched by the metal-containing heme of cyt c. In the presence of trypsin, cyt c was digested, thus phosphorescence of Cu NCs remained. Therefore, a new and continuous phosphorescence assay for the detection of trypsin activity and its inhibitor screening was established. The plot of relative fluorescence versus trypsin concentration obtains a good linear detection range from 0 to 20 ng/mL (R2 = 0.9657), and a detection limit of 2 ng/mL, which is much lower than 20 ng/mL of the sensor in buffer solution because of urine amplifying the phosphorescence signal of Cu NCs based on the FRET strategy. This assay still has been successfully applied to trypsin inhibitor screening, demonstrating its potential application in drug discovery.

Simple and label-free liquid crystal-based sensor for detecting trypsin coupled to the interaction between cationic surfactant and BSA.

Trypsin plays a central role in catalyzing the hydrolysis of peptide bonds, so a technique with simple operation is needed to monitor the activity of trypsin. Here a simple and label-free senor based on liquid crystals (LCs) was developed by employing bovine serum albumin (BSA) as the enzyme substrate and dodecyl trimethyl ammonium bromide (DTAB) as the controller for the alignment of LC. It was found that DTAB could form a self-assembled monolayer at the aqueous/LC interface to produce the dark optical images of LCs. And the addition of BSA could disturb the monolayer, so that the optical signal of LCs turned bright from dark. But the hydrolysis of BSA by trypsin resulted in the dark appearance. The sensing platform allows detection as low as 1 U/mL under the polarized light microscope based on at least three measurements. Moreover, this method was successfully applied in the detection of trypsin in human urines, suggesting its potential applications in clinic diagnosis.

Acinar cell density at the pancreatic resection margin is associated with post-pancreatectomy pancreatitis and the development of postoperative pancreatic fistula.

BACKGROUND: There has been recent evidence supporting post-pancreatectomy pancreatitis as a factor in the development of postoperative pancreatic fistula (POPF). The aims of this study were to evaluate: (i) the correlation of the acinar cell density at the pancreatic resection margin with the intra-operative amylase concentration (IOAC) of peri-pancreatic fluid, postoperative pancreatitis, and POPF; and (ii) the association between postoperative pancreatitis on the first postoperative day and POPF. METHODS: Consecutive patients who underwent pancreatic resection between June 2016 and July 2017 were included for analysis. Fluid for IOAC was collected, and amylase concentration was determined in drain fluid on postoperative days 1, 3, and 5. Serum amylase and lipase and urinary trypsinogen-2 concentrations were determined on the first postoperative day. Histology slides of the pancreatic resection margin were scored for acinar cell density. RESULTS: Sixty-one patients were included in the analysis. Acinar cell density significantly correlated with IOAC (r = 0.566, p < 0.001), and was significantly associated with postoperative pancreatitis (p < 0.001), and POPF (p = 0.003). Postoperative pancreatitis was significantly associated with the development of POPF (OR 17.81, 95%CI 2.17-145.9, p = 0.001). DISCUSSION: The development of POPF may involve a complex interaction between acinar cell density, immediate leakage of pancreatic fluid, and postoperative pancreatitis.

A novel magnetic/photoluminescence bifunctional nanohybrid for the determination of trypsin.

In this work, we have designed a novel kind of nanohybrid with magnetic and photoluminescence (PL) property for trypsin detection. The modified magnetic Fe3O4 nanoparticles (MNPs) with polydopamine (PDA) and human serum albumin (HSA) were prepared through a one step self-polymerization under mild condition. The polydopamine (PDA) coating on MNPs can improve the biocompatibility of the MNP-PDA-HAS composite due to its hydrophilicity and multifunctional groups. When MNP-PDA-HSA composite was added into the Anti-HSA modified CdTe QDs (anti-HSA-QDs), HSA on the MNP-PDA-HSA composite was captured by the site of anti-HSA-QDs to form MNP-PDA-HSA/anti-HSA-QDs nanohybrid. Therefore, the photoluminescence of QDs can be quenched by Fe3O4 nanoparticles due to the electron transfer. In the presence of trypsin, the protein (anti-HSA) was digested by trypsin and QDs was separated from the nanohybrid surface. As a result, the photoluminescence intensity of QDs was recovered. The magnetic/luminescent bifunctional nanohybrid displayed excellent analytical performance for the detection of trypsin in the range of 0.5-30µg/mL with a low detection limit of 0.25µg/mL.

A selective and sensitive fluorescent probe for the determination of HSA and trypsin.

A simple fluorescent probe HBI-GR based on the combination of the fluorophore (p-HBI) in green fluorescent protein (GFP) and Guanine riboside (GR) for HSA was successfully synthesized. HBI-GR showed an obvious fluorescence enhancement toward HSA without interference from other proteins, amino acids, anions and commonly existing metal ions. HBI-GR exhibited high sensitivity towards HSA with a good linear relationship between the fluorescence intensity of HBI-GR and HSA concentration from 0 to 0.06mgmL-1. The limit of detection, based on a signal-to-noise ratio of 3, was 15.09ngmL-1, which was much lower than that of most other reported probes. HBI-GR was almost non-fluorescent because of the bond twisting in the exited state of chromophore HBI. After binding to the hydrophobic pocket of HSA, it showed an obvious fluorescence enhancement due to the rigidifying of the flexible chromophore HBI by the hydrophobic environment. The resulting HBI-GR/HSA system also showed a satisfactory sensing ability toward trypsin through decreased fluorescence intensity with the detection limit of 0.0282ngmL-1. The fluorescence decreasing process was occurred as the lysine and arginine amino acids residues of HSA were cleaved by trypsin, which led to further exposure of HBI-GR to the PBS buffer phase and a concomitant decrease of the HBI-GR fluorescence intensity. Moreover, the probe HBI-GR was successfully used to detect HSA in healthy human urine and human blood serum samples. The practical application of the HBI-GR/HSA system for trypsin detection in healthy human urine also achieved satisfactory result.

Serum amylase and lipase and urinary trypsinogen and amylase for diagnosis of acute pancreatitis.

BACKGROUND: The treatment of people with acute abdominal pain differs if they have acute pancreatitis. It is important to know the diagnostic accuracy of serum amylase, serum lipase, urinary trypsinogen-2, and urinary amylase for the diagnosis of acute pancreatitis, so that an informed decision can be made as to whether the person with abdominal pain has acute pancreatitis. There is currently no Cochrane review of the diagnostic test accuracy of serum amylase, serum lipase, urinary trypsinogen-2, and urinary amylase for the diagnosis of acute pancreatitis. OBJECTIVES: To compare the diagnostic accuracy of serum amylase, serum lipase, urinary trypsinogen-2, and urinary amylase, either alone or in combination, in the diagnosis of acute pancreatitis in people with acute onset of a persistent, severe epigastric pain or diffuse abdominal pain. SEARCH METHODS: We searched MEDLINE, Embase, Science Citation Index Expanded, National Institute for Health Research (NIHR HTA and DARE), and other databases until March 2017. We searched the references of the included studies to identify additional studies. We did not restrict studies based on language or publication status, or whether data were collected prospectively or retrospectively. We also performed a 'related search' and 'citing reference' search in MEDLINE and Embase. SELECTION CRITERIA: We included all studies that evaluated the diagnostic test accuracy of serum amylase, serum lipase, urinary trypsinogen-2, and urinary amylase for the diagnosis of acute pancreatitis. We excluded case-control studies because these studies are prone to bias. We accepted any of the following reference standards: biopsy, consensus conference definition, radiological features of acute pancreatitis, diagnosis of acute pancreatitis during laparotomy or autopsy, and organ failure. At least two review authors independently searched and screened the references located by the search to identify relevant studies. DATA COLLECTION AND ANALYSIS: Two review authors independently extracted data from the included studies. The thresholds used for the diagnosis of acute pancreatitis varied in the trials, resulting in sparse data for each index test. Because of sparse data, we used -2 log likelihood values to determine which model to use for meta-analysis. We calculated and reported the sensitivity, specificity, post-test probability of a positive and negative index test along with 95% confidence interval (CI) for each cutoff, but have reported only the results of the recommended cutoff of three times normal for serum amylase and serum lipase, and the manufacturer-recommended cutoff of 50 mg/mL for urinary trypsinogen-2 in the abstract. MAIN RESULTS: Ten studies including 5056 participants met the inclusion criteria for this review and assessed the diagnostic accuracy of the index tests in people presenting to the emergency department with acute abdominal pain. The risk of bias was unclear or high for all of the included studies. The study that contributed approximately two-thirds of the participants included in this review was excluded from the results of the analysis presented below due to major concerns about the participants included in the study. We have presented only the results where at least two studies were included in the analysis.Serum amylase, serum lipase, and urinary trypsinogen-2 at the standard threshold levels of more than three times normal for serum amylase and serum lipase, and a threshold of 50 ng/mL for urinary trypsinogen-2 appear to have similar sensitivities (0.72 (95% CI 0.59 to 0.82); 0.79 (95% CI 0.54 to 0.92); and 0.72 (95% CI 0.56 to 0.84), respectively) and specificities (0.93 (95% CI 0.66 to 0.99); 0.89 (95% CI 0.46 to 0.99); and 0.90 (95% CI 0.85 to 0.93), respectively). At the median prevalence of 22.6% of acute pancreatitis in the studies, out of 100 people with positive test, serum amylase (more than three times normal), serum lipase (more than three times normal), and urinary trypsinogen (more than 50 ng/mL), 74 (95% CI 33 to 94); 68 (95% CI 21 to 94); and 67 (95% CI 57 to 76) people have acute pancreatitis, respectively; out of 100 people with negative test, serum amylase (more than three times normal), serum lipase (more than three times normal), and urinary trypsinogen (more than 50 ng/mL), 8 (95% CI 5 to 12); 7 (95% CI 3 to 15); and 8 (95% CI 5 to 13) people have acute pancreatitis, respectively. We were not able to compare these tests formally because of sparse data. AUTHORS' CONCLUSIONS: As about a quarter of people with acute pancreatitis fail to be diagnosed as having acute pancreatitis with the evaluated tests, one should have a low threshold to admit the patient and treat them for acute pancreatitis if the symptoms are suggestive of acute pancreatitis, even if these tests are normal. About 1 in 10 patients without acute pancreatitis may be wrongly diagnosed as having acute pancreatitis with these tests, therefore it is important to consider other conditions that require urgent surgical intervention, such as perforated viscus, even if these tests are abnormal.The diagnostic performance of these tests decreases even further with the progression of time, and one should have an even lower threshold to perform additional investigations if the symptoms are suggestive of acute pancreatitis.

FRET-based modified graphene quantum dots for direct trypsin quantification in urine.

A versatile nanoprobe was developed for trypsin quantification with fluorescence resonance energy transfer (FRET). Here, fluorescence graphene quantum dot is utilized as a donor while a well-designed coumarin derivative, CMR2, as an acceptor. Moreover, bovine serum albumin (BSA), as a protein model, is not only served as a linker for the FRET pair, but also a fluorescence enhancer of the quantum dots and CMR2. In the presence of trypsin, the FRET system would be destroyed when the BSA is digested by trypsin. Thus, the emission peak of the donor is regenerated and the ratio of emission peak of donor/emission peak of acceptor increased. By the ratiometric measurement of these two emission peaks, trypsin content could be determined. The detection limit of trypsin was found to be 0.7 µg/mL, which is 0.008-fold of the average trypsin level in acute pancreatitis patient's urine suggesting a high potential for fast and low cost clinical screening.

Gold nanoclusters-based chemiluminescence resonance energy transfer method for sensitive and label-free detection of trypsin.

A chemiluminescence resonance energy transfer (CRET) platform was developed for sensitive and label-free detection of protease by using trypsin as a model analyte. In this CRET platform, bis(2,4,6-trichlorophenyl)oxalate-hydrogen peroxide chemiluminescence (CL) reaction was utilized as an energy donor and bovine serum albumin (BSA)-stabilized gold nanoclusters (Au NCs) as an energy acceptor. The BSA-stabilized Au NCs triggered the CRET phenomenon by accepting the energy from TCPO-H2O2 CL reaction, thus producing intense CL. In the presence of trypsin, the protein template of BSA-stabilized Au NCs was digested, which frustrated the energy transfer efficiency between the CL donor and the BSA-stabilized Au NCs, leading to a significant decrease in the CL signal. The decreased CL signal was proportional to the logarithm of trypsin concentration in the range of 0.01-50.0µg mL(-1). The detection limit for trypsin was 9ng mL(-)(1) and the relative standard deviations were lesser than 3% (n=11). This Au NCs-based CRET platform was successfully applied to the determination of trypsin in human urine samples, demonstrating its potential application in clinical diagnosis.

[Clinical and laboratory diagnosis of an acute biliary pancreatitis].

In 126 patients, suffering an acute biliary pancreatitis (ABP), clinical examination was conducted. In 65 patients (1-st group) the isolated cholecystolithiasis was noted; in 35 (2-nd group)--cholelithiasis, which did not cause obturation of common biliary duct; in 26 (3-rd group)--cholelithiasis, which caused the biliary ways obturation (including calculi, which were incorporated into the duodenal papilla magna ostium). Clinical course of an ABP have differed depending on localization of calculi of extrahepatic biliary ducts. In patients, suffering ABP, a biochemical signs of hepatocytes functional disorders were observed, impacting the need for hepatoprotector preparations inclusion into complex of perioperative conservative therapy. Determination of activity of pancreatic α-amylase in the blood serum and conduction of the ACTIM Pancreatitis test con- stitute the most sensitive and specific methods of the ABP biochemical diagnosis.

Urinary trypsinogen-2 for diagnosing acute pancreatitis: a meta-analysis.

BACKGROUND: Currently, serum amylase and lipase are the most popular laboratory markers for early diagnosis of acute pancreatitis with reasonable sensitivity and specificity. Urinary trypsinogen-2 (UT-2) has been increasingly used but its clinical value for the diagnosis of acute pancreatitis and post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis has not yet been systematically assessed. DATA SOURCES: A comprehensive search was carried out using PubMed (MEDLINE), Embase, and Web of Science for clinical trials, which studied the usefulness of UT-2 as a diagnostic marker for acute pancreatitis. Sensitivity, specificity and the diagnostic odds ratios (DORs) with 95% confidence interval (CI) were calculated for each study and were compared with serum amylase and lipase. Summary receiver-operating curves were conducted and the area under the curve (AUC) was evaluated. RESULTS: A total of 18 studies were included. The pooled sensitivity and specificity of UT-2 for the diagnosis of acute pancreatitis were 80% and 92%, respectively (AUC=0.96, DOR=65.63, 95% CI: 31.65-139.09). The diagnostic value of UT-2 was comparable to serum amylase but was weaker than serum lipase. The pooled sensitivity and specificity for the diagnosis of post-ERCP pancreatitis were 86% and 94%, respectively (AUC=0.92, DOR=77.68, 95% CI: 24.99-241.48). CONCLUSIONS: UT-2 as a rapid test could be potentially used for the diagnosis of post-ERCP pancreatitis and to an extent, acute pancreatitis. Further studies are warranted to confirm these results.

Highly sensitive, label-free colorimetric assay of trypsin using silver nanoparticles.

Herein, we report a simple, sensitive label-free colorimetric assay of trypsin based on silver nanoparticles (AgNPs) aggregation. Generally, a specially designed short peptide chain acts as both the stabilizer of AgNPs and the substrate of trypsin. In the presence of trypsin, the negatively charged part of peptides will be hydrolyzed, leaving the positively charged dipeptide capped on the surface of AgNPs. The electrostatic property alteration then leads to the AgNPs' aggregation in certain salt condition. The solution color may change correspondingly due to the localized surface plasmon resonance, which can be monitored by naked eye and UV-vis spectrophotometry. This novel AgNPs-based colorimetric method for quantitative determination of trypsin has a linear detection range from 2.5 to 200 ng mL(-1) and a rather low detection limit down to 2 ng mL(-1). The determination of trypsin can also be realized in complex biological fluids by the proposed method, demonstrating its great potential utility in the clinical applications in the future.

A novel optical nanoprobe for trypsin detection and inhibitor screening based on Mn-doped ZnSe quantum dots.

In this paper, a novel optical nanoprobe (Mn:ZnSe d-dots-Arg(6)) for trypsin detection and its inhibitor screening has been constructed successfully based on the fluorescence quenching and recovery of Mn:ZnSe d-dots. Mn:ZnSe d-dots would aggregate in the presence of positively charged Arg(6) (six arginine residues) due to electrostatic interactions that result in the fluorescence quenching. Arg(6) can be hydrolyzed into small fragments in the presence of trypsin, and accordingly, the aggregation of Mn:ZnSe d-dots can be prohibited, which lead to the fluorescence recovery. Experimental results show that the recovery in fluorescence intensity is linearly proportional to the concentration of trypsin within the range of 0.1-12.0 µg mL(-1) with a detection limit of 40 ng mL(-1) under the optimized experimental conditions. We also prove the feasibility of fluorescence recovery of Mn:ZnSe d-dots for trypsin detection through the resonance light scattering (RLS) technique. Additionally, the optical nanoprobe can be employed for screening the inhibitors of trypsin. The optical nanoprobe was successfully applied for the determination of trypsin in human serum and urine samples with good accuracy and satisfactory recovery.

The risk for immediate postoperative complications after pancreaticoduodenectomy is increased by high frequency of acinar cells and decreased by prevalent fibrosis of the cut edge of pancreas.

OBJECTIVES: Soft pancreas is considered as a factor for pancreatitis after pancreaticoduodenectomy, which in turn constitutes a high risk for local complications. The aim was to analyze the proportion of different cell types in the cut edge of pancreas (CEP) in relation to postoperative pancreatitis and other complications after pancreaticoduodenectomy. METHODS: Data from postoperative follow-up was collected on 40 patients who had undergone pancreaticoduodenectomy. Positive urine trypsinogen-2, an early detector of pancreatitis, was checked on days 1 to 6 after operation. Drain amylase was measured on postoperative day 3. Anastomotic leakages, delayed gastric emptying, and other complications were registered. The areas of different cell types were calculated from the entire hematoxylin-eosin-stained section of CEP. RESULTS: High frequency of acinar cells in the CEP significantly increased positive urine trypsinogen-2 days, drain amylase values, and delayed gastric emptying. In a subgroup of patients with more than 40% acini in the CEP, there were significantly more postoperative complications. Increased fibrosis correlated with a small number of positive urine trypsinogen-2 days and postoperative complications. CONCLUSIONS: A large number of acinar cells in the CEP increases, whereas extensive fibrosis in the CEP decreases, the risk for postoperative complications after pancreaticoduodenectomy. These results emphasize the importance of acini in the development of postoperative complications.

Rapid urinary trypsinogen-2 test in the early diagnosis of acute pancreatitis: a meta-analysis.

OBJECTIVES: Urinary trypsinogen-2 has been implicated as a promising biomarker for the early diagnosis of acute pancreatitis (AP). The meta-analysis was used to establish the overall accuracy of urinary trypsinogen-2 test for diagnosing AP. METHODS: Based on comprehensive searches of the PubMed and Embase databases, we identified and abstracted outcome data from all articles evaluating the diagnostic value of urinary trypsinogen-2. A summary estimate for sensitivity, specificity, 95% confidence region and 95% prediction region was calculated using the bivariate random-effects approach. RESULTS: The meta-analysis included 13 studies (2342 patients, the proportion of severe AP from 13.21% to 30.00%). Overall, the pooled sensitivity was 82.3% (95%CI 79.3%-85.1%) and specificity was 93.5% (95%CI 92.2%-94.6%). The diagnostic odds ratios (DOR) was 85.23 (95%CI 40.14-180.99). The area under the summary ROC curve (AUC) was 0.9673. CONCLUSION: The urinary trypsinogen-2 test is a reliable and rapid method for the early diagnosis of AP.