Primary needle-knife fistulotomy for preventing post-endoscopic retrograde cholangiopancreatography pancreatitis: Importance of the endoscopist's expertise level.

BACKGROUND: Needle-knife fistulotomy (NKF) is used as a rescue technique for difficult cannulation. However, the data are limited regarding the use of NKF for primary biliary cannulation, especially when performed by beginners. AIM: To assess the effectiveness and safety of primary NKF for biliary cannulation, and the role of the endoscopist's expertise level (beginner vs expert). METHODS: We retrospectively evaluated the records of 542 patients with naïve prominent bulging papilla and no history of pancreatitis, who underwent bile duct cannulation at a tertiary referral center. The patients were categorized according to the endoscopist's expertise level and the technique used for bile duct cannulation. We assessed the rates of successful cannulation and adverse events. RESULTS: The baseline characteristics did not differ between the experienced and less-experienced endoscopists. The incidence rate of post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis (PEP) was significantly affected by the endoscopist's expertise level in patients who received conventional cannulation with sphincterotomy (8.9% vs 3.4% for beginner vs expert, P = 0.039), but not in those who received NKF. In the multivariable analysis, a lower expertise level of the biliary endoscopist (P = 0.037) and longer total procedure time (P = 0.026) were significant risk factor of PEP in patients who received conventional cannulation with sphincterotomy but only total procedure time (P = 0.004) was significant risk factor of PEP in those who received NKF. CONCLUSION: Primary NKF was effective and safe in patients with prominent and bulging ampulla, even when performed by less-experienced endoscopist. We need to confirm which level of endoscopist's experience is needed for primary NKF through prospective randomized study.

Case of Bleeding Ileal Varices after a Colectomy Diagnosed by Capsule Endoscopy.

We report a case of bleeding ileal varices associated with intra-abdominal adhesions after colectomy which was successfully diagnosed using capsule endoscopy. A 77-year-old woman visited the emergency department for several episodes of melena. She had a medical history of neoadjuvant chemo-radiation therapy and subsequent surgery for rectal cancer 6 years previously. Conventional diagnostic examinations including upper endoscopy, colonoscopy, and abdominal computed tomography could not detect any bleeding focus, however, following capsule endoscopy revealed venous dilatations with some fresh blood in the distal ileum, indicating bleeding ileal varices. The patient underwent exploratory laparotomy and the affected ileum was successfully resected. No further gastrointestinal bleeding occurred during the 6 months follow-up. Small intestinal varices are important differential for obscure gastrointestinal bleeding especially in patients with a history of abdominal surgery in the absence of liver cirrhosis, and capsule endoscopy can be a good option for diagnosing small intestinal varices.

Measurement of progesterone in human serum by isotope dilution liquid chromatography-tandem mass spectrometry and comparison with the commercial chemiluminescence immunoassay.

Progesterone is one of the steroid hormones. The hormone is especially important in preparing the uterus for the implantation of the blastocyst and in maintaining pregnancy. Its concentration in serum is measured to determine ovarian function and to predict early pregnancy. The progesterone concentration is also important for in-vitro fertilization and embryo-transfer outcomes. We have established isotope dilution liquid chromatography-tandem mass spectrometry as a primary method for the measurement of progesterone in human serum. Progesterone and its isotopic analogue, progesterone-(13)C(2), in serum were monitored at mass transitions of m/z 315.2/109.2 and 317.2/111.2 respectively in multiple-reaction monitoring (MRM) mode with electrospray positive ionization. For validation of the method, progesterone in a National Institute of Standards and Technology standard reference material (NIST SRM) was measured, and the measured results were in good agreement with the reference values within the uncertainty. On the basis of the established method, progesterone certified reference material (CRM) was developed in this work. The certified value was (1.41 ± 0.036) µg kg(-1). The repeatability of 1.1% and reproducibility of 0.14% showed that ID LC-MS-MS is a reliable and reproducible method. The expanded uncertainty for the measurement of progesterone in the CRM was approximately 2.6% within 95% confidence limits. The detection limit of progesterone was approximately 0.6 µg kg(-1). The progesterone CRMs were distributed to representative clinical laboratories in the Republic of Korea for comparison with the chemiluminescence immunoassay (CLIA), which is the most sensitive immunoassay method. The results from the comparison showed quite a large bias among the participating laboratories. This implies that the CRM is a very important material for establishment of traceability to its practical use.

Theoretical calculations for mass resolution of a quadrupole ion trap reflectron time-of-flight mass spectrometer.

We have developed a theoretical method of predicting the mass resolution for a quadrupole ion trap reflectron time-of-flight (QIT-reTOF) mass spectrometer as a function of the spatial and velocity distributions of ions, voltages applied to the electrodes, and dimensions of the instrument. The flight times of ions were calculated using theoretical equations derived with an assumption of uniform electric fields inside the QIT and with the analytical description of the potential including the monopole, dipole, and quadrupole components. The mass resolution was then estimated from the flight-time spread of the ions with finite spatial and velocity distributions inside the QIT. The feasibility of the theoretical method was confirmed by the reasonable agreement of the theoretical resolution with the experimental one measured by varying the extraction voltage of the QIT or the deceleration voltage of the reflectron. We found that the theoretical resolution estimated with the assumption of the uniform electric fields inside the QIT reproduced the experimental one better than that with the analytical description of the potential. The possible applications of this theoretical method include the optimization of the experimental parameters of a given QIT-reTOF mass spectrometer and the design of new instruments with higher mass resolution.