With the advance of drug development and research techniques, the drug metabolic processes and mechanism can be more deeply achieved. As the drug metabolism and pharmacokinetics process are mediated by drug metabolizing enzymes and transporters, study of drug metabolizing enzymes and transporters has become an important part for drug development. The traditional immunoassays with low sensitivity and poor specificity can not reflect the accurate expression level of drug metabolizing enzymes and transporters. We now give a brief review on the quantitative study of drug metabolizing enzymes and transporters by mass spectrometry-based proteomic approach.
Enzymes ; chemistry ; Humans ; Inactivation, Metabolic ; Mass Spectrometry ; Membrane Transport Proteins ; chemistry ; Pharmacokinetics ; Proteomics

The fragmentation pathways of five estrogens (estradiol, estrone, equilin sulfate, 17 a-dihydroequilin sulfate and equilenin sulfate) have been studied with high resolution and high mass accuracy using electrospray ionization quadrupole time-of-flight mass spectrometry (ESI-Q-TOF/MS) in the negative ion mode. Molecular weights were obtained from [M-H](-) ions in the product ion spectra. The results indicate that the five structurally similar estrogens have similar fragmentation pathways. Using their stable isotope forms as internal reference compounds, the accurate mass and composition of the fragment ions were determined. During collision-induced dissociation (CID), cleavage is initiated by loss of oxygen atoms from carbon-17, after which D and C rings cleave sequentially and rearrange to finally form stable conjugate structures with highly abundant characteristic fragment ions at m/z 183 (accompanied by m/z 181), m/z 169 and m/z 145 (accompanied by m/z 143). Understanding these characteristic fragmentation pathways of estrogens will be helpful in identifying the structures of steroid hormones in general.
Chemical Fractionation ; methods ; Equilenin ; chemistry ; Equilin ; analogs & derivatives ; chemistry ; Estradiol ; chemistry ; Estrogens ; chemistry ; Estrone ; chemistry ; Ions ; Spectrometry, Mass, Electrospray Ionization

The fragmentation pathways of two taxanes drugs have been studied in positive ion mode by Q-TOF with the advantages of high mass accuracy and high resolution analysis. The [M+H] + ions were observed by ESI-MS, from which the molecular weights were obtained. Using the protonated pseudo-molecular ions [M+H]+ as internal reference compounds, the accurate mass and element composition of the fragment ions were determined. The collision induced dissociation (CID) data of the [M+H] ions provided fragmentation pathways of related compounds. Results showed that the major cleavage pathways of paclitaxel and docetaxel were the same that the cleavage of C-O bond between the side chain and taxol skeleton easily occurred, then stripping of the functional groups on the parent ring. Some common fragments were formed, such as m/z 105.033 7, 291.137 3, 309.148 5, 327.159 7, 387.181 2 and 509.217 4, which would provide a basis for future qualitative and quantitative analysis of taxanes in vitro and in vivo.
Paclitaxel ; chemistry ; Peptide Fragments ; chemistry ; Spectrometry, Mass, Electrospray Ionization ; methods ; Taxoids ; chemistry

AIMTo isolate and identify a glucuronide metabolite of SFZ-47 [3H-1,2-dihydro-2-(4-methyl-phenylamino)methyl-1-pyrrolizinone], which is difficult to synthesize because it undergoes hydrolysis and intramolecular acyl migration at physiological pH, in rabbit urine.

METHODSTwo rabbits were ig 200 mg doses of SFZ-47. Urine was collected for 24 h, adjusted to pH 4.0 with acetic acid and lyophilized. The residues were reconstituted in 25 mL methanol and centrifuged at 5,000 r.min-1 for 10 min. The supernatant was filtered (0.45 micron) and then isolated with semi-preparative reversed phase HPLC. The eluent collected from individual peaks was evaporated by rotary evaporation and freeze-drying. Compounds were then identified with electrospray ion trap mass spectrometry and 1HNMR spectroscopy.

RESULTSThe 1HNMR and ESI-MSn results indicate that the metabolite is the 1-O-acyl beta-D-glucuronide conjugate of 4-(3H-1,2-dihydro-1-pyrrolizinone-2-methylamino) benzoic acid.

CONCLUSIONThis method was shown to be rapid and simple and gave excellent resolution from endogenous constituents in urine, and it is suitable for preparation of the glucuronide metabolites of SFZ-47 and its analogues.

Animals ; Anti-Inflammatory Agents, Non-Steroidal ; metabolism ; urine ; Chromatography, High Pressure Liquid ; Male ; Molecular Structure ; Pyrroles ; chemistry ; metabolism ; urine ; Rabbits ; Spectrometry, Mass, Electrospray Ionization

AIMTo investigate the fragmentation behavior of triazolobenzodiazepines and to develop a specific, sensitive and rapid LC/MSn assay for simultaneous determination of estazolam, alprazolam and triazolam in human urine.

METHODSAfter oral administration of a single 4 mg dose of the drugs to each of three healthy volunteers, urine samples were purified by solid-phase extraction, and then injected into an ODS column (150 mm x 4.6 mm) with a mobile phase of methanol-water (8:2) for LC/MSn analysis. The structures of estazolam, alprazolam and triazolam in human urine were identified by direct comparison of the observed mass spectra and the chromatographic retention time with those of the reference substance. The mass spectrometer (Finnigan LCQ) was operated in positive mode and in two scan modes including SIM and full scan MS/MS mode. The obtained mass spectra was analyzed assisted with the software Mass Frontier 1.0 for their fragmentation pathways.

RESULTSThe full scan MS/MS spectra of each compound gave characteristic fragment ions of [M + H - N2]+ and [M + H - Cl]+. The detection limit was below 0.5 ng.mL-1 for estazolam, alprazolam and triazolam in human urine.

CONCLUSIONThe method is useful in forensic and clinical toxicology in which unequivocal identification of eatazolam, alprazolam and triazolam is desired.

Alprazolam ; urine ; Anti-Anxiety Agents ; urine ; Chromatography, Liquid ; Estazolam ; urine ; Humans ; Male ; Spectrometry, Mass, Electrospray Ionization ; Triazolam ; urine

The paper is aimed to provide a novel index, named as multidimensional spatial triangular area, for the evaluation of the release-absorption correlation of multiple component traditional Chinese medicines (TCMs). The applicability of the method was demonstrated by the example data. The method and standard practice for evaluation of the release-absorption correlation for western medicines with single compound could not be applied to TCMs with multiple components. The release percentage or absorption percentage of the multiple components for TCMs at the sampling time was a point in the multidimensional space. The area of the triangle formed byt the sequential three points represented the changing characteristics of the components' release and absorption kinetics. The side lengths of the triangle could be calculated from the spatial distances between each two of the sequential three points. Then the triangle area could be obtained by the side lengths. The in vitro release-in vivo absorption correlation of the multiple components could be represented by the correlation between the integrating values of the release triangle areas and that of the absorption triangle areas. The results of the examples indicated that the multidimensional spatial triangular area method could treat the multiple components in a holistic way, in line with the holism the hi he TCMs. Therefore, the multidimensional spatial triangular area method provided new methodology for the release-absorption correlation of the TCMs with multiple components.
Algorithms ; Chemistry Techniques, Analytical ; Drug Combinations ; Drugs, Chinese Herbal ; analysis ; isolation & purification ; pharmacokinetics ; Medicine, Chinese Traditional ; Plants, Medicinal ; chemistry

Objective To explore the value of dual-phase contrast-enhancement multislice computed tomography (MSCT) in the assessment of acute myocardial infarction volume and perfusion in porcine models. Methods The distal left anterior descending coronary arteries of 5 pigs were balloon-occluded for 90 min and followed by reperfusion. MSCT was performed 1 min (early phase) and 5 min (delayed phase) after administration bolus of 100 mL of iodinated contrast material 30 min after reperfusion. On the same day, hearts were excised, sectioned in 8 mm short-axis slices, and stained with TTC. Infarction volume was defined as the sum of the hyper-enhanced area and surrounding hypo-enhanced area in all slices on delay enhanced phase of MSCT and the TTC-negative area on TTC staining slices. Infarction volume was expressed as percentage of total slice volume. Results Acute infarction detected by MSCT was characterized by early myocardial perfasion defects in the early phase of the contrast bolus (early defects) with surrounding residual defects and late enhancement observed in the late phase. Mean CT attenuation value of early defects was significantly different from CT attenuation value of remote myocardium [(213±55)HU vs (304±30)HU](P < 0.05), CT attenuation values of residual defects and late enhancement were also significantly different from those of remote myocardium [(360±75) HU vs (90±37) HU and (152±23) HU vs (190±37) HU, repectively](P < 0.01, P < 0.05). The mean infarction volume was (8.9± 1.0)% on MSCT and (9.2±1.4)% on TTC pathology images. The infarction volume assessed by MSCT compared well with TTC staining slices. Conclusion Acute reperfused myocardial infarction zone has specific enhancement pattens different to remote normal zone on dual phase MDCT, which is in good agreement with in vivo Trc pathology in the assessment of acute reperfused myocardial infarction shortly offer reperfusion.

BACKGROUNDThe urokinase plasminogen activator system is believed to play an important role in degradation of the extracellular matrix associated with cartilage and bone destruction; however its precise roles in temporomandibular disorders have not yet been clarified. The aims of this study were to investigate the gene expression of fibrinolytic factors urokinase plasminogen activator (uPA) and plasminogen activator inhibitor-1 (PAI-1) in the articular cartilage of rabbit temporomandibular joint (TMJ) with disc displacement (DD) and to probe the relationship between fibrinolytic activity and cartilage remodeling.

METHODSDisc displacement of right joints was performed in 36 of 78 rabbits under investigation. The animals were sacrificed at 4 days and 1, 2, 4, 8 and 12 weeks after surgery, respectively. The right joints of these animals were harvested and processed for the examination of mRNA expression of uPA and PAI-1 in articular cartilage using in situ hybridization techniques.

RESULTSThe expression of uPA and PAI-1 was co-expressed weakly in the chondrocytes from transitive zone to hypertrophic zone and mineralized zone, while no hybridizing signals were shown in proliferative zone and superficial zone in control rabbits. The most striking was the up-regulation of uPA and PAI-1 mRNA in 4-day rabbits postoperatively at the onset of cartilage degeneration. The strongest hybridizing signals for uPA and PAI-1 were seen in 2-week rabbits postoperatively. After 2 weeks, the expression of uPA and PAI-1 began to decrease and reached nearly normal level at 12 weeks.

CONCLUSIONSThe expression of the uPA/PAI-1 system coincides with the pathological changes in condylar cartilage after DD. The uPA/PAI-1 system may be one of the essential mediators in articular cartilage remodeling.

Animals ; Cartilage, Articular ; metabolism ; Female ; Joint Dislocations ; metabolism ; pathology ; Male ; Mandibular Condyle ; metabolism ; pathology ; Plasminogen Activator Inhibitor 1 ; genetics ; RNA, Messenger ; analysis ; Rabbits ; Temporomandibular Joint ; metabolism ; Temporomandibular Joint Disc ; Urokinase-Type Plasminogen Activator ; genetics

OBJECTIVETo investigate the effect of anterior disc displacement on the expression of urokinase plasminogen activator and its inhibitor-1 (uPA/PAI-1) in synovial tissues.

METHODSForty Japanese white rabbits were used in this study. The animals were killed at 4 days, 1, 2, 4, 8 and 12 weeks postoperatively, respectively. In situ hybridization technology was applied to detect the expression of uPA/PAI-1 mRNA in synovial membrane.

RESULTSIn normal synovial tissues, synovial lining cells and a few fibrosblasts with mild positive staining were occasionally seen. More synovial lining cells and fibrosblasts with moderate postive signals were found 1 week after operation. Since then, the degree of staining for uPA/PAI-1 increased gradually. By the end of 12 weeks postoperatively, strong signals of uPA/PAI-1 mRNA were detected.

CONCLUSIONThere is a harmonized uPA/PAI-1 system existing in synovial tissues. The high expression of uPA and PAI-1 mRNA in synovial tissues indicates that the uPA/PAI-1 system may play an important role in the process of synovitis resulted from anterior disc displacement.

Animals ; In Situ Hybridization ; Plasminogen ; Plasminogen Activator Inhibitor 1 ; RNA, Messenger ; Rabbits ; Synovial Membrane ; Urokinase-Type Plasminogen Activator

OBJECTIVETo compare the differences in intrapulmonary shunt (Qs/Qt) and arterial oxygenation between selective left lower lobar blockade by Coopdech endobronchial blocker tubes (BB) and one lung ventilation (OLV) by left-sided double-lumen endobronchial tubes (DLT) in patients with normal pulmonary function.

METHODSThirty-six patients (aged 32-64 years) scheduled for lower esophageal surgery were allocated randomly into BB and DLT groups (n=18). Anesthesia was induced and maintained with Propofol by target controlled infusion with intravenous administration of sufentanil and cisatracurium if needed. A 35 to 39 French tube was placed in the DLT group, and an 8.0-mm (internal diameter) single-lumen endotracheal tube was used in the BB group where a 9 French Coopdech BB was advanced into the left lower lobar bronchus guided by a fiberoptic bronchoscope. The variables recorded were blood gas analysis data from the venous and arterial blood samples at 20 min after two-lung ventilation in supine position (T(1)), 20 min after initiation of one-lung ventilation or selective left lower lobar blockade by inflating BB balloons in the right lateral decubitus position (T(2)), total collapse of the left lung or the left lower lobe after the pleura was opened (T(3)), and before tracheal extubation (T(4)). Qs/Qt was calculated using a standard formula based on the three-compartment model. Upon pleura opening, the effectiveness of lung collapse was evaluated by the surgeon who performed the surgery. Chest radiograph and arterial blood gas analyses were performed the day after the operation.

RESULTSBoth of the groups were similar with regard to rank of the surgical exposure, pH, PaCO(2), hemoglobin from T(1) to T(4), Qs/Qt, PaO(2), PO(2), and oxygenation index at T1. In BB group, a significant reduction of Qs/Qt and greater improvements in PaO(2), PO(2), oxygenation index at T(2), T(3) and T(4) were observed in comparison with those in DLT group (P<0.05 or <0.01). No lobe collapse was observed postoperatively in BB group, but 2 patients in DLT group showed left lower lobe atelectasis. The patients in BB group showed better postoperative arterial oxygenation and shorter postoperative hospital stay (P<0.01).

CONCLUSIONSelective left lower lobar blockade by Coopdech endobronchial blocker tube during lower esophageal surgery provides a lower intraoperative intrapulmonary shunt and a better intra- and postoperative arterial oxygenation..

Adult ; Blood Gas Analysis ; Bronchoscopes ; Continuous Positive Airway Pressure ; instrumentation ; methods ; Esophageal Neoplasms ; surgery ; Female ; Fiber Optic Technology ; Humans ; Intubation, Intratracheal ; methods ; Lung ; physiology ; Male ; Middle Aged ; Oxygen ; administration & dosage ; blood ; pharmacology ; Pulmonary Ventilation ; Thoracic Surgical Procedures ; methods