Isotope-dilution LC-MS/MS analysis of the elastin crosslinkers desmosine and isodesmosine in acute cerebral stroke patients.

Utilizing chemically synthesized an isotopically labeled internal standard, isodesmosine-13C3,15N1, an isotope-dilution LC-MS/MS method was established. Concentrations of desmosine and isodesmosine in plasma of acute cerebral stroke patients and healthy controls were determined. The concentration of desmosines was markedly higher in plasma from acute stroke patients compared with healthy controls. Desmosines are thus novel biomarkers for evaluating the extent of vascular injury after acute cerebral stroke.

[Efficacy of Combined Therapy(Drainage of the Bile Duct, High-Dose Hepatic Artery Infusion, and Radiation)for Hilar Cholangiocellularcarcinoma with Complete Portal Vein Obstruction].

We reported a case of hilar cholangiocellularcarcinoma with complete obstruction of the portal vein. The patient, who was a 65-year-old woman, suffered from fever and general fatigue as a result of acute cholangitis after insertion of a tube stent into the right bile duct. The main tumor was present on the right side of S1 and spread to both sides of the bile duct. S1 lobe was swollen and diffuse intrahepatic invasion was noted in the right lobe and S1. The portal vein was completely obstructed at the porta hepatis with a coronary vein-left renal vein shunt. We immediately administered a high-dose hepatic arterialinfusion( 5-FU 1 g×3 days: one day off 1 g×3 days)(HDHAI)to the right hepatic artery using a transient catheter insertion method. After 2 courses of HDHAI, the intrahepatic invasion decreased. However, after 4 courses of HDHAI(2 on the right side and 2 on the left side), the invasion on the left side of the IVC had increased. We then chose radiation therapy. Subsequently, transient cystic changes were observed; however, 4 months after radiation, the invasion on the left side of the IVC had regrown into the cardia. The patient suffered from vomiting as a result of the narrowing of the esophagus. We chose HDHAI and dilation of the esophagus using a balloon. Finally, the invasion on the left side of the IVC and S1 swelling decreased, and she could eat again. Thirteen months later, she remains an outpatient. We recommend HDHAI and radiation therapy to hilar cholangiocellularcarcinoma even if the portal vein is completely obstructed.

[(13)C3,(15)N1]-labeled isodesmosine: A potential internal standard for LC-MS/MS analysis of desmosines in elastin degradation.

Isodesmosine and desmosine are crosslinking amino acids that are present only in elastin. They are useful biomarkers for the degradation of elastin, which occurs during the progression of chronic obstructive pulmonary disease (COPD) and related diseases. This Letter describes the synthesis of [(13)C3,(15)N1]-labeled isodesmosine, using Chichibabin pyridine synthesis as a key reaction. The labeled isodesmosine is a potential internal standard for the quantitative LC-MS/MS analysis of desmosines in elastin degradation.

Development and performance evaluation of a positive reference material for hemolysis testing.

This study deals with the development and performance evaluation of a positive reference material for hemolysis testing, which is used for evaluating the biological safety of medical devices. Genapol X-080, a nonionic detergent, was selected as a candidate hemolytic substance in a survey of 23 chemical compounds; it showed significant hemolytic activity against rabbit defibrinated blood at concentrations more than 20 µg/mL. A polyvinyl chloride (PVC) sheet spiked with 0.6% (w/w) of the compound exhibited weak hemolytic activity in direct contact and/or extract-based assays after 4 h incubation at 37°C. A PVC sheet containing 5.8% (w/w) Genapol X-080 induced complete hemolysis in both assays. The amount of Genapol X-080 eluted from each PVC sheet during hemolysis testing using the direct contact method increased time-dependently and reached 25.6 (former sheet) or 1154 (later sheet) µg/mL after 4 h incubation, which was similar to or much higher than the critical micelle concentration, respectively. Similar elution behavior was observed using the extract-based method, and the Genapol X-080 content in test solutions prepared by autoclave extraction of both sheets was 22.5 and 358 µg/mL, respectively, indicating a clear relationship between the degree of hemolytic activity and the eluted amount of Genapol X-080. Thus, a PVC sheet spiked with a compound exhibiting different hemolytic activity depending on its concentration may be useful as a positive reference material to validate the hemolysis tests.

Comparative inhibition of tetrameric carbonyl reductase activity in pig heart cytosol by alkyl 4-pyridyl ketones.

CONTEXT AND OBJECTIVE: The present study is to elucidate the comparative inhibition of tetrameric carbonyl reductase (TCBR) activity by alkyl 4-pyridyl ketones, and to characterize its substrate-binding domain. MATERIALS AND METHODS: The inhibitory effects of alkyl 4-pyridyl ketones on the stereoselective reduction of 4-benzoylpyridine (4-BP) catalyzed by TCBR were examined in the cytosolic fraction of pig heart. RESULTS: Of alkyl 4-pyridyl ketones, 4-hexanoylpyridine, which has a straight-chain alkyl group of five carbon atoms, inhibited most potently TCBR activity and was a competitive inhibitor. Furthermore, cyclohexyl pentyl ketone, which is substituted by cyclohexyl group instead of phenyl group of hexanophenone, had much lower ability to be reduced than hexanophenone. DISCUSSION AND CONCLUSION: These results suggest that in addition to a hydrophobic cleft corresponding to a straight-chain alkyl group of five carbon atoms, a hydrophobic pocket with affinity for an aromatic group is located in the substrate-binding domain of TCBR.