L-ascorbic acid metabolism in an ascorbate-rich kiwifruit (Actinidia. Eriantha Benth.) cv. 'White' during postharvest.

Kiwifruit (Actinidia eriantha Benth.) 'White', a novel cultivar with higher L-ascorbic acid (AsA) level, is registered in China. Changes in AsA, related metabolites, enzymatic activity, and gene expression associated with AsA biosynthesis and recycling process were investigated in this paper. The results indicated that AsA biosynthesis through L-galactose pathway supplemented by D-galacturonic acid pathway and AsA recycling collectively contributed to accumulating and remaining higher AsA level in kiwifruit cv. 'White' during postharvest. Moreover, L-galactose dehydrogenase (GalDH) activity and relative expressions of the genes encoding GDP-D-mannose pyrophosphorylase (GMP), L-galactose-1-P phosphatase (GPP), GDP-L-galactose phosphorylase (GGP), GalDH and D-galacturonate reductase (GalUR) were important for regulation of AsA biosynthesis, and the activity and expression of dehydroascorbate reductase (DHAR) were primarily responsible for regulation of AsA recycling in kiwifruit 'White' during postharvest.

Role of tRNA selenocysteine 1 associated protein 1 in the proliferation and apoptosis of cardiomyocyte­like H9c2 cells.

Transfer RNA selenocysteine 1 associated protein 1 (Trnau1ap) serves an essential role in the synthesis of selenoproteins, which have critical functions in numerous biological processes. Selenium deficiency results in a variety of diseases, including cardiac disease. However, the mechanisms underlying myocardial injury induced by selenium deficiency remain unclear. The present study examined the effects of Trnau1ap under­ and overexpression in cardiomyocyte­like H9c2 cells, by transfection with small interfering RNA and an overexpression plasmid, respectively. Expression levels of glutathione peroxidase, thioredoxin reductase and selenoprotein K were decreased in Trnau1ap­underexpressing cells, and increased in Trnau1ap­overexpressing cells. Using MTT, proliferating cell nuclear antigen, annexin V and caspase­3 activity assays, it was demonstrated that reducing Trnau1ap expression levels inhibited the proliferation of H9c2 cells and induced apoptosis. Conversely, increasing Trnau1ap expression levels promoted cell growth. Western blot analysis revealed that the phosphoinositide 3­kinase/protein kinase B signaling pathway was activated in Trnau1ap­underexpressing cells. Furthermore, the apoptotic pathway was activated in these cells, evidenced by relatively greater expression levels of B­cell lymphoma (Bcl­2)­associated X protein and reduced expression levels of Bcl­2. Taken together, these findings suggest that Trnau1ap serves a key role in the proliferation and apoptosis of H9c2 cells. The present study provides insight into the underlying mechanisms of myocardial injury induced by selenium deficiency.

Decoding brain responses to pixelized images in the primary visual cortex: implications for visual cortical prostheses.

Visual cortical prostheses have the potential to restore partial vision. Still limited by the low-resolution visual percepts provided by visual cortical prostheses, implant wearers can currently only "see" pixelized images, and how to obtain the specific brain responses to different pixelized images in the primary visual cortex (the implant area) is still unknown. We conducted a functional magnetic resonance imaging experiment on normal human participants to investigate the brain activation patterns in response to 18 different pixelized images. There were 100 voxels in the brain activation pattern that were selected from the primary visual cortex, and voxel size was 4 mm × 4 mm × 4 mm. Multi-voxel pattern analysis was used to test if these 18 different brain activation patterns were specific. We chose a Linear Support Vector Machine (LSVM) as the classifier in this study. The results showed that the classification accuracies of different brain activation patterns were significantly above chance level, which suggests that the classifier can successfully distinguish the brain activation patterns. Our results suggest that the specific brain activation patterns to different pixelized images can be obtained in the primary visual cortex using a 4 mm × 4 mm × 4 mm voxel size and a 100-voxel pattern.

Deformable image registration for temporal subtraction of chest radiographs.

PURPOSE: Temporal subtraction images constructed from image registration can facilitate the visualization of pathologic changes. In this study, we propose a deformable image registration (DIR) framework for creating temporal subtraction images of chest radiographs. METHODS: We developed a DIR methodology using two different image similarity metrics, varying flow (VF) and compressible flow (CF). The proposed registration method consists of block matching, filtering, and interpolation. Specifically, corresponding point pairs between reference and target images are initially determined by minimizing a nonlinear least squares formulation using grid-searching optimization. A two-step filtering process, including least median of squares filtering and backward matching filtering, is then applied to the estimated point matches in order to remove erroneous matches. Finally, moving least squares is used to generate a full displacement field from the filtered point pairs. RESULTS: We applied the proposed DIR method to 10 pairs of clinical chest radiographs and compared it with the demons and B-spline algorithms using the five-point rating score method. The average quality scores were 2.7 and 3 for the demons and B-spline methods, but 3.5 and 4.1 for the VF and CF methods. In addition, subtraction images improved the visual perception of abnormalities in the lungs by using the proposed method. CONCLUSION: The VF and CF models achieved a higher accuracy than the demons and the B-spline methods. Furthermore, the proposed methodology demonstrated the ability to create clinically acceptable temporal subtraction chest radiographs that enhance interval changes and can be used to detect abnormalities such as non-small cell lung cancer.

Effectiveness of YouTube as a Source of Medical Information on Heart Transplantation.

BACKGROUND: In this digital era, there is a growing tendency to use the popular Internet site YouTube as a new electronic-learning (e-learning) means for continuing medical education. Heart transplantation (HTx) remains the most viable option for patients with end-stage heart failure or severe coronary artery disease. There are plenty of freely accessible YouTube videos providing medical information about HTx. OBJECTIVE: The aim of the present study is to determine the effectiveness of YouTube as an e-learning source on HTx. METHODS: In order to carry out this study, YouTube was searched for videos uploaded containing surgical-related information using the four keywords: (1) "heart transplantation", (2) "cardiac transplantation", (3) "heart transplantation operation", and (4) "cardiac transplantation operation". Only videos in English (with comments or subtitles in English language) were included. Two experienced cardiac surgeons watched each video (N=1800) and classified them as useful, misleading, or recipients videos based on the HTx-relevant information. The kappa statistic was used to measure interobserver variability. Data was analyzed according to six types of YouTube characteristics including "total viewership", "duration", "source", "days since upload", "scores" given by the viewers, and specialized information contents of the videos. RESULTS: A total of 342/1800 (19.00%) videos had relevant information about HTx. Of these 342 videos, 215 (62.8%) videos had useful information about specialized knowledge, 7/342 (2.0%) were found to be misleading, and 120/342 (35.1%) only concerned recipients' individual issues. Useful videos had 56.09% of total viewership share (2,175,845/3,878,890), whereas misleading had 35.47% (1,375,673/3,878,890). Independent user channel videos accounted for a smaller proportion (19% in total numbers) but might have a wider impact on Web viewers, with the highest mean views/day (mean 39, SD 107) among four kinds of channels to distribute HTx-related information. CONCLUSIONS: YouTube videos on HTx benefit medical professionals by providing a substantial amount of information. However, it is a time-consuming course to find high-quality videos. More authoritative videos by trusted sources should be posted for dissemination of reliable information. With an improvement of ranking system and content providers in future, YouTube, as a freely accessible outlet, will help to meet the huge informational needs of medical staffs and promote medical education on HTx.

Modeling lung deformation: a combined deformable image registration method with spatially varying Young's modulus estimates.

PURPOSE: Respiratory motion introduces uncertainties in tumor location and lung deformation, which often results in difficulties calculating dose distributions in thoracic radiation therapy. Deformable image registration (DIR) has ability to describe respiratory-induced lung deformation, with which the radiotherapy techniques can deliver high dose to tumors while reducing radiation in surrounding normal tissue. The authors' goal is to propose a DIR method to overcome two main challenges of the previous biomechanical model for lung deformation, i.e., the requirement of precise boundary conditions and the lack of elasticity distribution. METHODS: As opposed to typical methods in biomechanical modeling, the authors' method assumes that lung tissue is inhomogeneous. The authors thus propose a DIR method combining a varying intensity flow (VF) block-matching algorithm with the finite element method (FEM) for lung deformation from end-expiratory phase to end-inspiratory phase. Specifically, the lung deformation is formulated as a stress-strain problem, for which the boundary conditions are obtained from the VF block-matching algorithm and the element specific Young's modulus distribution is estimated by solving an optimization problem with a quasi-Newton method. The authors measure the spatial accuracy of their nonuniform model as well as a standard uniform model by applying both methods to four-dimensional computed tomography images of six patients. The spatial errors produced by the registrations are computed using large numbers (>1000) of expert-determined landmark point pairs. RESULTS: In right-left, anterior-posterior, and superior-inferior directions, the mean errors (standard deviation) produced by the standard uniform FEM model are 1.42(1.42), 1.06(1.05), and 1.98(2.10) mm whereas the authors' proposed nonuniform model reduces these errors to 0.59(0.61), 0.52(0.51), and 0.78(0.89) mm. The overall 3D mean errors are 3.05(2.36) and 1.30(0.97) mm for the uniform and nonuniform models, respectively. CONCLUSIONS: The results indicate that the proposed nonuniform model can simulate patient-specific and position-specific lung deformation via spatially varying Young's modulus estimates, which improves registration accuracy compared to the uniform model and is therefore a more suitable description of lung deformation.

5-Methyl-3,3-bis-(4-methyl-piperazin-1-yl)-1-[2-(4-methyl-piperazin-1-yl)eth-yl]indolin-2-one.

In the title compound, C(26)H(43)N(7)O, each piperazine ring adopts a chair conformation. Two 1-methyl-piperazine rings bond to one Csp(3) of the pyrrole ring via the piperazine N atoms, while the third one links to the N atom of the indolin-2-one unit through a flexible ethyl group with an almost syn conformation. In the crystal, mol-ecules are connected through methyl-ene-carbonyl C-H⋯O inter-actions into an infinite chain along the c axis. The almost parallel arrays are stacked, forming a three-dimensional framework.

A high-throughput dielectrophoresis-based cell electrofusion microfluidic device.

A high-throughput cell electrofusion microfluidic chip has been designed, fabricated on a silicon-on-insulator wafer and tested for in vitro cell fusion under a low applied voltage. The developed chip consists of six individual straight microchannels with a 40-µm thickness conductive highly doped Si layer as the microchannel wall. In each microchannel, there are 75 pairs of counter protruding microelectrodes, between which the cell electrofusion is performed. The entire highly doped Si layer is covered by a 2-µm thickness aluminum film to maintain a consistent electric field between different protruding microelectrode pairs. A 150-nm thickness SiO2 film is subsequently deposited on the top face of each protruding microelectrode for better biocompatibility. Owing to the short distance between two counter protruding microelectrodes, a high electric field can be generated for cell electrofusion with a low voltage imposed across the electrodes. Both mammalian cells and plant protoplasts were used to test the cell electrofusion. About 42-68% cells were aligned to form cell-cell pairs by the dielectrophoretic force. After cell alignment, cell pairs were fused to form hybrid cells under the control of cell electroporation and electrofusion signals. The averaged fusion efficiency in the paired cells is above 40% (the highest was about 60%), which is much higher than the traditional polyethylene glycol method (<5%) and traditional electrofusion methods (∼12%). An individual cell electrofusion process could be completed within 10 min, indicating a capability of high throughput.

An intelligent electronic capsule system for automated detection of gastrointestinal bleeding.

In clinical practice, examination of the hemorrhagic spot (HS) remains difficult. In this paper, we describe a remote controlled capsule (RCC) micro-system with an automated, color-based sensor to identify and localize the HS of the gastrointestinal (GI) tract. In vitro testing of the detecting sensor demonstrated that it was capable of discriminating mimetic intestinal fluid (MIF) with and without the hemoglobin (Hb) when the concentration of Hb in MIF was above 0.05 g/ml. Therefore, this RCC system is able to detect the relatively accurate location of the HS in the GI tract.

Pharmacokinetics of aminophylline delivered to the small intestine and colon using remote controlled capsules.

BACKGROUND: A patented remote controlled capsule (RCC) has recently been developed to provide noninvasive drug delivery to selected sites in the human gut that allows assessment of regional gastrointestinal (GI) drug absorption under a normal physiological environment. The objective of this study was to investigate the rate and extent of aminophylline absorption after site-specific delivery of the drug in the GI tract using RCC and a magnetic marker monitoring (MMM) technique. METHODS: This study was conducted in twelve healthy male subjects, in a three-treatment, randomized, crossover manner with a 7-day washout. Eligible subjects received a 150 mg aminophylline dose through an oral administration, or via a remote controlled capsule, delivered to the small bowel or ascending colon. MMM was employed to monitor the GI transit of the RCC, and the radio-frequency signal was used to activate capsules at target sites. Blood samples were obtained at regular intervals until 24 hours post dose/activation. Plasma theophylline concentrations were measured by a TDx System Analyzer. A comparison of the PK profile with the oral dosing route of aminophylline was performed after delivery to the small bowel and colon. RESULTS: The RCC was well tolerated in volunteers. The mean capsule activation time for the small bowel and ascending colon was 2.07 hours and 6.08 hours post dose. Aminophylline had similar absorption profiles from the small bowel compared with the stomach, with an area under the curve (AUC(t)) ratio of 92% vs. the stomach, but a lower absorption profile from the ascending colon, with an AUC(t) ratio of 47.2% vs. the stomach. CONCLUSIONS: The proprietary of the RCC and MMM technique offer the opportunity to obtain data on the intestinal absorption of a drug in humans under noninvasive conditions. Aminophylline is rapidly and efficiently absorbed from the small bowel. While colonic absorption was limited by the poor water condition although effective absorption was observed from the ascending colon. This provides an opportunity for rational development of modified-release formulations as well as alternative dosage forms.

[Value of three-dimensional contrast-enhanced magnetic resonance angiography in the diagnosis of mesenteric arteriosclerosis].

OBJECTIVE: To assess the clinical value of three-dimensional contrast-enhanced magnetic resonance angiography (3D-CE-MRA) in the diagnosis of mesenteric arteriosclerosis. METHODS: 3D-CE-MRA of the mesenteric arteries was performed in 21 patients with 23 healthy subjects as the control. After 3D image reconstruction and maxi intense projection, and the abnormalities of the mesenteric arteries were observed and analyzed. The diameter and number of the arterial branches were compared between the patients and the control subjects. RESULTS: All the 21 patients suffered arteriosclerosis in the arteries other than the mesenteric arteries. On 3D-CE-MRA, mesenteric arteriosclerosis was characterized by thinning of the arterial trunk, luminal stenosis, irregular arterial margins and homo- or heterogeneous thickening of vascular walls. Multiple filling defects were found in the mesenteric artery lumens with reduced second order branches, which showed rigid lining with dashed line appearance or disappeared in some cases. The inferior mesenteric arteries were seen in only 2 patients. The diameters of superior and inferior mesenteric arteries were 3.8-/+0.32 mm and 1.20-/+0.12 mm in the patients, significantly smaller than those of in the control subjects (6.51-/+1.01 mm and 2.90-/+0.90 mm, respectively, P<0.01). The number of the mesenteric artery branch of the patients was also significantly reduced as compared with that in the control subjects (P<0.05). In som cases, the intestinal enhancement was attenuated with the intestinal contraction, dilatation and lowering of the intestinal tension. CONCLUSION: 3D-CE-MRA can clearly display mesenteric arteriosclerosis and secondary intestinal changes, and provides a useful means for the diagnosis and assisting the therapy of mesenteric arteriosclerosis.

Study of the inhibitory effect of fatty acids on the interaction between DNA and polymerase beta.

The binding of human DNA polymerase beta (pol beta) to DNA template-primer duplex and single-stranded DNA in the absence or presence of pol beta inhibitors has been studied using a surface plasmon resonance biosensor. Two fatty acids, linoleic acid and nervonic acid, were used as potent pol beta inhibitors. In the interaction between pol beta and DNA, pol beta could bind to ssDNA in a single binding mode, but bound to DNA template-primer duplexes in a parallel mode. Both pol beta inhibitors prevented the binding of pol beta to the single strand overhang and changed the binding from parallel to single mode. The affinities of pol beta to the template-primer duplex region in the presence of nervonic acid or linoleic acid were decreased by 20 and 5 times, respectively. The significant inhibitory effect of nervonic acid on the pol beta-duplex interaction was due to both a 2-fold decrease in the association rate and a 9-fold increase in the dissociation rate. In the presence of linoleic acid, no significant change of association rate was observed, and the decrease in binding affinity of pol beta to DNA was mainly due to 7-fold increase in the dissociation rate.

[Folate receptor-mediated antitumor drugs].

Folate receptor (FR) is over-expressed in a variety of human cancers and it is seldom expressed or found in normal tissues. Therefore, folate receptor-mediated antitumor drugs can be targeted specially to the FR-positive tumor cells. This strategy improves the selectivity of drugs which may destroy the normal tissues in traditional chemotherapeutics. This review provides the delivery mechanism of FR-mediated antitumor drugs and highlights the novel folate-drug conjugates and their activities.

Microfluidic pool structure for cell docking and rapid mixing.

A microfluidic pool structure for cell docking and rapid mixing is described. The pool structure is defined as a microchamber on one structural layer of a bilayer chip and connects with two or more individual microchannels on the other structural layer. In contrast to the turbulent flow in a macroscale pool, laminar streams enter and exit this microfluidic pool structure with definite and controllable direction that may be influenced by the location and geometry of the pool. A simple microfluidic model was used to validate this hypothesis. In this model, a microscale pool structure was made on the lower layer of a chip and connected with three parallel microchannels in the upper layer. Simulation and experimental results indicated that the flow profile within the pool structure was determined by its geometry and location. This could be used as a flow control method and it was simpler than designs based on microvalve, hydraulic pressure, or electrokinetic force, and has some important applications. For example, controllable streams within this structure were used to immobilize biological cells along the microchannel walls. When different solution streams flowed through the pool, rapid diffusion of analytes occurred for short diffusion distance between vertical flow laminas. Furthermore, desired dilution (mixing) ratio could be obtained by controlling the geometry of the microfluidic pool.

[Expression of vascular endothelial growth factor C in pancreatic cancer and its effect upon lymph node metastasis].

OBJECTIVE: To investigate the expression of vascular endothelial growth factor C (VEGF-C) and the effect of antisense oligonucleotide (ASODN) upon lymph node metastasis of pancreatic cancer cell. METHODS: We selected 15 cases of human pancreatic cancer and detected the expression of VEGF-C in primary tumor and lymph node metastasis tissues with immunohistochemistry. Meanwhile, the spontaneous lymphatic metastasis model in nude mice was established with orthotopic implantation for the human pancreatic cancer cell line PANC-1, isolation and culture of primary tumor and spontaneous lymphatic metastasis. The effect of VEGF-C special ASODN upon the apoptosis of pancreatic cancer cell derived from primary tumor and spontaneous lymphatic metastasis were detected by reverse transcription polymerase chain reaction (RT-PCR), enzyme linked immunosorbent assay (ELISA), flow cytometer and terminal deoxynucleotidyl transferase mediated-dUTP nick end labeling (TUNEL). RESULTS: In tissues of human pancreatic cancer, the values of VEGF-C on lymph nodes metastasis were more higher than primary tumor (P < 0.05). About the expression of VEGF-C on pancreatic cancer cell derived from spontaneous lymphatic metastasis and primary tumor in nude mice model, the mRNA levels of VEGF-C were 0.87 +/- 0.11 and 0.61 +/- 0.15 respectively, the VEGF-C levels in culture supernatants were (1682 +/- 157) pg/ml and (1404 +/- 128) pg/ml. The expression of VEGF-C on pancreatic cancer cells derived from lymphatic metastasis were also more higher than primary tumor (P < 0.05). In vitro and vivo, transfection of VEGF-C ASODN decreased the expression of VEGF-C in pancreatic cancer cell. In control group, scramble-sense oligonucleotide (SODN) group and ASODN group, the apoptosis rates of pancreatic cancer cells derived from lymph node metastasis were (2.8 +/- 1.0)%, (5.0 +/- 2.1)%, (13.2 +/- 2.2)% respectively in vitro, and were (1.8 +/- 0.5)%, (2.0 +/- 0.7)%, (4.4 +/- 1.0)% respectively in vivo, the apoptosis was increased significantly after transfection of VEGF-C ASODN (all P < 0.01). But pancreatic cancer cells derived from primary tumor were not effected (all P > 0.05). CONCLUSION: In human pancreatic cancer and nude mice model, the expression of VEGF-C on lymphatic metastasis was higher than primary tumor. The apoptosis of pancreatic cancer cells derived from spontaneous lymphatic metastasis were promoted by transfection of VEGF-C ASODN specially.

Rapid analysis of alpha-fetoprotein by chemiluminescence microfluidic immunoassay system based on super-paramagnetic microbeads.

A rapid and sensitive chemiluminescence microfluidic immunoassay system based on super-paramagnetic microbeads for determination of alpha-fetoprotein (AFP) is described. In this system we use CO(2) laser to fabricate microfluidic chip, and use super-paramagnetic microbeads as solid carrier of antibody, chemiluminescence as detection signal. With this system we can perform AFP analysis within 20 min, and the linear range of AFP concentration is 1 approximately 800 ng/mL, the detection limit is 0.23 ng/mL. By this method no separation or preconcentration steps are needed. Most of all, the chip can be reused.

Non-thermal ablation of rabbit liver VX2 tumor by pulsed high intensity focused ultrasound with ultrasound contrast agent: Pathological characteristics.

AIM: To investigate the pathological characteristics of non-thermal damage induced by pulsed high intensity focused ultrasound (PHIFU) combined with ultrasound contrast agent (UCA), SonoVue (Bracco SpA, Milan, Italy) in rabbit liver VX2 tumor. METHODS: Liver VX2 tumor models were established in 20 rabbits, which were divided randomly into PHIFU combined with ultrasound contrast agent group (PHIFU + UCA group) and sham group. In the PHIFU + UCA group, 0.2 mL of SonoVue was injected intravenously into the tumor, followed by ultrasound exposure of I(SP) 5900 W/cm(2). The rabbits were sacrificed one day after ultrasound exposure. Specimens of the exposed tumor tissues were obtained and observed pathologically under light microscope and transmission electron microscope. The remaining tumor tissues were sent for 2,3,5-Triphenyltetrazolium chloride (TTC) staining. RESULTS: Before TTC staining, tumor tissues in both the sham and the PHIFU + UCA groups resembled gray fish meat. After TTC staining, the tumor tissues were uniformly stained red, with a clear boundary between tumor tissue and normal tissue. Histological examination showed signs of tumor cell injury in PHIFU + UCA group, with cytoplasmic vacuoles of various sizes, chromatin margination and karyopyknosis. Electron microscopic examination revealed tumor cell volume reduction, karyopyknosis, chromatin margination, intercellular space widening, the presence of high electron-density apoptotic bodies and vacuoles in cytoplasm. CONCLUSION: The non-thermal effects of PHIFU combined with UCA can be used to ablate rabbit liver VX2 tumors.

Iron contributes to the formation of catechol isoquinolines and oxidative toxicity induced by overdose dopamine in dopaminergic SH-SY5Y cells.

OBJECTIVE: The selective loss of dopaminergic neurons in Parkinson's disease is suspected to correlate with the increase of cellular iron, which may be involved in the pathogenesis of PD by promotion of oxidative stress. This research investigated dopamine-induced oxidative stress toxicity contributed by iron and the production of dopamine-derived neurotoxins in dopaminergic SH-SY5Y cells. METHODS: After the SH-SY5Y cells were pre-incubated with dopamine and Fe2+ for 24 h, the cell viability, hydroxyl radical, melondialdehyde, cell apoptosis, and catechol isoquinolines were measured by lactate dehydrogenase assay, salicylic acid trapping method, thiobarbuteric acid assay, Hoechst 33258 staining and HPLC-electrochemical detection (HPLC-ECD), respectively. RESULTS: (1) Optimal dopamine (150 micromol/L) and Fe2+ (40 or 80 micromol/L) significantly increased the concentrations of hydroxy radicals and melondialdehyde in SH-SY5Y cells. (2) Induction with dopamine alone or dopamine and Fe2+ (dopamine/Fe2+) caused cell apoptosis. (3) Compared with untreated cells, the catechol isoquinolines, salsolinol and N-methyl-salsolinol in dopamine/Fe2+-induced cells were detected in increasing amounts. CONCLUSION: Due to dopamine/Fe2+-induced oxidative stress similar to the state in the parkinsonian substantia nigra neurons, dopamine and Fe2+ impaired SH-SY5Y cells could be used as the cell oxidative stress model of Parkinson's disease. The catechol isoquinolines detected in cells may be involved in the pathogenesis of Parkinson's disease as potential neurotoxins.

[Design of a microfluidic immunoassay system based on superparamagnetic microbeads].

We use direct-write laser micromachining technology to fabricate the microfluidic chip, and to establish a microfluidic chemiluminescence immunoassay system based on superparamagnetic microbeads, for detecting alpha- fetoprotein (AFP). The AFP analysis can be completed in 20 minutes with 5 microl sample and 5 microl reagent, and there is a good linear correlation in the range of 1-800 ng/ml.