Tao Song

Bioartificial liver system based on choanoid fluidized bed bioreactor improve the survival time of fulminant hepatic failure pigs

Bioartificial liver (BAL) support system has been proposed as potential treatment method for end‐stage liver diseases. We described an improved BAL system based on a choanoid fluidized bed bioreactor containing alginate–chitosan encapsulated primary porcine hepatocytes. The feasibility, safety, and efficiency of this device were estimated using an allogeneic fulminant hepatic failure (FHF) model. FHF was induced with intravenous administration of D‐galactosamine. Thirty FHF pigs were divided into three groups: (1) an FHF group which was only given intensive care; (2) a sham BAL group which was treated with the BAL system with empty encapsulation, and (3) a BAL group which was treated with the BAL system containing encapsulated freshly isolated primary porcine hepatocytes. The survival times and biochemical parameters of these animals were measured, and properties of the encapsulations and hepatocytes before and after perfusion were also evaluated. Compared to the two control groups, the BAL‐treated group had prolonged the survival time and decreased the blood lactate levels, blood glucose, and amino acids remained stable. No obvious ruptured beads or statistical decline in viability or function of encapsulated hepatocytes were observed. This new fluidized bed BAL system is safe and efficient. It may represent a feasible alternative in the treatment of liver failure. Biotechnol. Bioeng. 2011;108:2229–2236.

Construction of modular novel bioartificial liver support system

A modular novel bioartificial liver support system was designed and constructed in order to simplify tedious operation of artificial liver treatment and to improve the applicability in the system. The design ideas, structure composition, system function, and etc, were described in detail. In this system, the variety of the therapy modes could be conveniently connected by the interface of modular structure. Industrial control computer was used as the main control platform, and physical of control parameters such as pressure, pump speed, dissolved oxygen, temperature, and etc, were transmitted into computer, then according to the instruction, process of the treatment was accomplished by the executing units implemented by main control system. Touch screen of human-computer interface was adopted, which made the system better operational and more comfortable. The system has passed the spot function test, and all indexes can meet requirements for the clinical treatment requested. It has the character such as modular design, systematic distribution, building-block structure, and etc, which supports a great novel operation platform for artificial therapy.

Combination of applied electric field and polyethylene glycol effectively enhance functional recovery in acute spinal cord injury of rats

Applied electric field stimulation (EFS) can reduce extracellular Ca2+ influx and consequently enhance functional recovery after spinal cord injury (SCI). However, the influx of Ca2+ continued through disrupted membranes when EFS completed. As polyethylene glycol (PEG) can reseal the damaged membranes, we proposed a hypothesis that combination therapy of EFS and PEG may effectively prevent Ca2+ influx and further promote functional recovery in rats subjected to SCI. Rats were randomly divided into three groups: saline group, treated with saline only; control group, treated with EFS and saline; and experimental group, treated with EFS and PEG. The effects of EFS combined with PEG were assessed by means of injury potential and Basso, Beattie, and Bresnahan (BBB) scores. Data showed that the injury potential at the moment of EFS termination in experimental group was significantly smaller compared with that in control group, but higher than that in saline group. Moreover, the BBB scores in experimental group were significantly higher than those in other groups. These findings suggest that combination therapy of EFS and PEG could further enhance functional recovery in acute SCI of rats.

Injury potentials of spinal cord in ex vivo compression injury model.

The effect of applied electric field on neuroprotection and axonal regeneration has been studied in previous studies of acute spinal cord injury (SCI). However, due to the complexity of the microenvironment of the lesion site, the underlying mechanism of applied electric field is not yet fully understood. Thus, the injury potential, a significant index of the microenvironment change, was investigated in ex vivo spinal cords compression injury. Spinal cords isolated from rat were cultured in a double sucrose gap recording chamber. Both compound action potential (CAP) and injury potential were measured. Compression induced the decreasement of compound action potential, but the amplitude of CAP increased gradually after decompression. Compression also lead to the appearance of injury potential, represented by the voltage difference between the gap potential before and after compression, and the injury potential decreased with time logarithmicly after decompression. Intracellular Na(+) and Ca(2+) concentrations were measured and results showed that after injury these ions flowed into intracellular space. Therefore, the current approach can provide a basis for investigating the formation mechanism of the injury potential and help understand the pathophysiology of the SCI.The effect of applied electric field on neuroprotection and axonal regeneration has been studied in previous studies of acute spinal cord injury (SCI). However, due to the complexity of the microenvironment of the lesion site, the underlying mechanism of applied electric field is not yet fully understood. Thus, the injury potential, a significant index of the microenvironment change, was investigated in ex vivo spinal cords compression injury. Spinal cords isolated from rat were cultured in a double sucrose gap recording chamber. Both compound action potential (CAP) and injury potential were measured. Compression induced the decreasement of compound action potential, but the amplitude of CAP increased gradually after decompression. Compression also lead to the appearance of injury potential, represented by the voltage difference between the gap potential before and after compression, and the injury potential decreased with time logarithmicly after decompression. Intracellular Na+ and Ca2+ concentrations were measured and results showed that after injury these ions flowed into intracellular space. Therefore, the current approach can provide a basis for investigating the formation mechanism of the injury potential and help understand the pathophysiology of the SCI.

Automated Extraction of Plant Viral RNA Using the Nucleic Acid Instrument Based on Magnetic Nanobeads

In this paper, an automated nucleic acid extraction instrument based on magnetic nanobeads is described. Also, a prototype is designed and constructed. Some plant viral RNA extraction experiments were done using the platform. And the experimental results demonstrated that the instrument could be successfully used for extraction of plant viral RNA，and the extracted RNA was successfully used in an automated PCR assay for the detection of plant virus. The Ct values of CGMMV RNA, LSV RNA and ArMV RNA at the initial concentration were 12.51, 17.81 and 23.48.

Design of Automatic Nucleic Acid Extraction Instrument Based on Magnetic Nanobeads

In this paper, an automatic nucleic acid extraction instrument is described. It consists of mechanical components, motor controlling module, temperature controlling module and computer. Also, a prototype has been designed and constructed. The maximum sample throughput of this prototype is 96, the sample volume is 300-1000ul, the maximum sample handling time is about 60min, the sample temperature controlling range is from room temperature to 95oC, and the accuracy of temperature controlling achieved is about ± 2oC.

Development of a novel artificial liver support system

Background/introduction: Artificial liver support treatment is a promising alternative to liver transplantation. An ideal artificial liver support system (ALSS) should be a combination of a nonbiological liver (NBL) device and a bioreactor based bioartificial liver (BAL). Material and methods: A novel ALSS which can not only fulfill toxin-removal functions of NBL but also provide biotransformation and synthetic functions of BAL is constructed. The unique dual-chamber reservoir can improve the efficiency of material exchange. The funnel-shaped fluidized bed bioreactor can provide an ideal physiological environment for hepatocytes. Quick bubble handling function improves the security during treatment. The software design provides error correction function. Our control center is an industrial personal computer and most components are integrated via the RS485 buses. The whole control system consists of three parts: a pump drive module, a sensor network and a human-machine communication interface. To verify our design, we test the system on miniature pigs. Results: The system runs normally in all treatment modes and meets the clinical requirements. Functions of all components are verified. Conclusions: The system provides a reliable research platform for artificial liver support treatment.

Voltage between Electrodes as a Key Parameter in Oscillating Field Stimulation of Spinal Cord in Rat

The regeneration of injured spinal cord in applied weak DC electrical field has been demonstrated for years. However, the most suitable stimulating intensity has not been confirmed because the mechanism of axonal regeneration in applied DC electrical field is absent. This paper used finite element method to analyze the distribution of electrical field before and after injury and the uniformity of electrical field induced by different number of stimulating electrodes. Moreover, we improved the implantable oscillating field stimulator (OFS) to make it more reliable, effective and steady. In animal experiment, voltages between stimulating electrodes have been successfully recorded in different conditions such as intact, injured, exposing spinal column and suturing skin. Simulation results showed that the uniformity of electrical field of three pairs of electrodes is better than that of one pair. Experimental results indicated that a stimulating current of 10µA could generate an approximate 500µV/mm electrical field on the exposed spinal cord of rat, but a lower electrical field after suturing. In addition, voltages between stimulating electrodes would increase in deed because of transection of spinal cord.

A method of nerve electrical stimulation by magnetic induction

The implantable electrical stimulator is usually not suitable for long term use because of its large size and short battery life, besides the magnetic stimulation can not provide deep nerve stimulation. Therefore, this paper developed a method of the electrical stimulation by using the magnetic induction. We implanted a small inductive coil which was connected with nerve electrodes. When the stimulation was applied, a coaxial coil containing a pulsed current was placed outside. So the electrical field evoking the nerve was formed because of the generation of inductive electromotive force in the inductive coil. Finite element analysis was used to analyze the electric field in the nerve and fiber model was used to predict the generation of action potential. This innovative method was applied on the sciatic nerves of rats. EMG was successfully recorded after the electrical stimulation by the magnetic induction. The results demonstrated that this new method was effective to stimulate the deep nerve.