Automated precolumn derivatization system for analyzing physiological amino acids by liquid chromatography/mass spectrometry

An automated method for high-throughput amino acid analysis, using precolumn derivatization high-performance liquid chromatography/electrospray mass spectrometry (HPLC/ESI-MS), was developed and evaluated. The precolumn derivatization step was performed in the reaction port of a home-built auto-sampler system. Amino acids were derivatized with 3-aminopyridyl-N-hydroxysuccinimidyl carbamate, and a 3 microm Wakosil-II 3C8-100HG column (100 x 2.1 mm i.d.) was used for separation. To achieve a 13 min cycle for each sample, the derivatization and separation steps were performed in parallel. The results of the method evaluation, including the linearity, and the intra- and inter-precision, were sufficient to measure physiological amino acids in human plasma samples. The relative standard deviations of typical amino acids in actual human plasma samples were below 10%.

Precolumn derivatization reagents for high-speed analysis of amines and amino acids in biological fluid using liquid chromatography/electrospray ionization tandem mass spectrometry

A rapid analytical method for amines and amino acids was developed, involving derivatization with the novel reagent 3-aminopyridyl-N-hydroxysuccinimidyl carbamate (APDS), followed by reversed-phase high-performance liquid chromatography and electrospray ionization tandem mass spectrometry (HPLC/ESI-MS/MS). More than 100 different analytes with amino groups, including amino acids in biological fluids such as mammalian plasma, could be measured within 10 min. The analytes were easily derivatized with APDS under the mild conditions. Selective reaction monitoring of ESI-MS/MS in positive mode was carried out to include the transitions of all of the protonated molecular ions of analytes derivatized with APDS to the common fragment at m/z 121, which was derived from the amino pyridyl moiety of the reagent. We evaluated the retention time precision, the quantification limits, the linearity, the intra- and inter-day precisions and the accuracy of 22 typical amino acids found in biological fluids, by analyzing a standard amino acid mixture and rat plasma. The intra-day relative standard deviations (RSDs) of the retention times of the 22 amino acids and their internal standards were within 0.9% and the inter-day RSDs were less than 1.1%, except for asparagines, with an RSD of 1.9%. The intra-day and inter-day RSDs of amino acid analyses in rat plasma were within 8.0% and 4.5%, respectively. The method, which facilitates the amino acid analysis of more than 100 samples in a day, represents an alternative to traditional amino acid analysis techniques, such as chromatography using postcolumn derivatization by ninhydrin.

[Extremely elderly patient in whom the pacing lead was implanted via the femoral vein]

We report on an extremely elderly patient in whom we were unable to insert a pacing lead via the subclavian or internal jugular vein because of a superior vena cava obstruction; we instead inserted the pacing lead via the femoral vein. The patient was a 98-year-old male. Thirty-nine years previously, pacemaker implantation was performed for complete atrioventricular block. Afterwards, pacemaker replacement and reimplantation had been performed a total of 15 times. The patient was recently admitted because of pacing failure. Pacemaker replacement was performed, but pacing was not possible because of disconnection of the pacing lead. Insertion of a new pacing lead was attempted via both subclavian veins and the right jugular vein but failed; this approach was abandoned and temporary pacing was done. Superior vena cava obstruction was noted on chest computed tomography (CT), and pacing lead insertion through the superior vena cava was deemed unfeasible. Myocardial electrode implantation was also considered, but general anesthesia was deemed problematic because of the patient's extreme age. A pacing lead was inserted via the right femoral vein, and the generator was implanted in the right lower abdomen. Postoperative pacing was satisfactory.

[Mediastinal and hilar lymph node of cancer unknown origin: 3 case reports]

We encountered three rare cases of cancer of unknown origin affecting the mediastinal and hilar lymph nodes. Patient 1 was a 63 year-old man. Chest X-ray and CT films revealed an enlarged right hilar lymph node. A right mediastinal and hilar lymphadenectomy was performed. The histological diagnosis was metastatic squamous cell carcinoma (SCC). SCC of the right upper lobe appeared 34 months after the operation, requiring a right pneumonectomy. Patient 1 was alive 43 months after his first operation. Patient 2 was a 73 year-old man in whom left mediastinal and hilar lymph node swelling had been detected. A mediastinoscopy and lymph node biopsy were performed. The histological findings resulted in a diagnosis of metastatic small cell carcinoma. Chemotherapy was initiated, and the patient was alive 5 months after the biopsy procedure, Patient 3 was a 57 year-old man in whom right mediastinal and hilar lymph node swelling had been disclosed by chest CT scans. We performed a medianosternotomy and mediastinal and right hilar lymphadenectomy. Histologically, the diagnosis was metastatic adenocarcinoma. After the operation, radiation therapy was performed on the patient's mediastinum. Patient 3 was alive 5 months after the initial operation. The patients were given diagnoses of T0N1 or T0N2 lung cancer.

[Peri- and postoperative courses in patients undergoing concomitant cardiac and pulmonary operations]

We studied peri- and postoperative courses in patients undergoing concomitant cardiac and pulmonary operations (CCPO), which included pulmonary resection and coronary artery bypass grafting (CABG). Of eight patients who had lung cancer and ischemic heart disease (IHD), six underwent CCPO and two patients first had percutaneous transluminal coronary angioplasty (PTCA) followed by lung surgery at an interval after the first procedure. Twelve patients with lung cancer who underwent only pulmonary surgery and 13 patients with IHD who were treated with CABG were studied as controls. We compared peri- and postoperative characteristics among these groups of patient. Operating time, bleeding volume during surgery, amount of drainage discharge within 24 hours after the operation, and ICU days were significantly increased in the CCPO group in comparison with the two control groups. In the CCPO group, mechanical ventilatory support time and administration days after the operation were significantly increased in comparison with the lung operation group, but not in comparison with CABG group. The two patients who sequentially underwent PTCA and lung surgery had postoperative courses similar to the CCPO patients. All CCPO patients were ambulatory upon discharge. None of the CCPO patients died from postoperative complications involving the respiratory tract or the circulatory system. Our data suggest that CCPO is available for patients with both heart and lung diseases when complications can be avoided by appropriate management, although these procedures are extremely invasive. We believe that CCPO should be attempted in patients with definite indications for such a procedure.