Identification of human LDHC4 as a potential target for anticancer drug discovery

One of the distinct hallmarks of cancer cells is aerobic glycolysis (Warburg effect). Lactate dehydrogenase A (LDHA) is thought to play a key role in aerobic glycolysis and has been extensively studied, while lactate dehydrogenase C (LDHC), an isoform of LDHA, has received much less attention. Here we showed that human LDHC was significantly expressed in lung cancer tissues, overexpression of Ldhc in mice could promote tumor growth, and knock-down of LDHC could inhibit the proliferation of lung cancer A549 cells. We solved the first crystal structure of human LDHC4 and found that the active-site loop of LDHC4 adopted a distinct conformation compared to LDHA4 and lactate dehydrogenase B4 (LDHB4). Moreover, we found that (ethylamino) (oxo)acetic acid shows about 10 times selective inhibition against LDHC4 over LDHA4 and LDHB4. Our studies suggest that LDHC4 is a potential target for anticancer drug discovery and (ethylamino) (oxo)acetic acid provides a good start to develop lead compounds for selective drugs targeting LDHC4.

Feasibility study of electronic nose for rapid screening of bacterial infection types in rat wounds / 中华创伤杂志

Objective:To detect the common pathogenic bacteria in rat wounds using electronic nose so as to explore the feasibility of electronic nose for rapid screening of pathogenic bacteria in clinic.Methods:The wound was cutted from the left and right side of the psoas muscle of 45 SD rats. The type of standard bacterial fluids applied to the wound was divided into Staphylococcus aureus group, Escherichia coli group, Pseudomonas aeruginosa group, Acinetobacter baumannii group and Klebsiella pneumoniae group according to the random number table, with 9 mice per group. Three days later, the wound pus was sent to culture. Five standard bacterial fluids were detected by electronic nose, and the overall recognition rate and individual recognition rate of standard bacterial fluids were calculated by neural network (BP). The wound pus in each group was detected by electronic nose to visually compare the overlap degree of the radar map of the wound pus with the standard bacterial fluid characteristic radar map. The detection rate of wound pus in each group by electronic nose was compared. The wound pus in each group was submitted for examination, and the clinical detection rate of wound pus in each group was compared. The consistency was compared between electronic nose test and clinical test.Results:The overall BP identification rate of five standard bacteria liquid was 93.2%. The BP single identification rate of the Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae reached over 99.0%, and was more than 88.0% for Pseudomonas aeruginosa and Acinetobacter baumannii. The radar pattern of wound pus was highly overlapped with the characteristics of radar pattern of standard bacterial fluid. The detection rate of wound pus by electronic nose was the highest (100.0%) in Pseudomonas aeruginosa group and Escherichia coli group, followed by 88.9% in Klebsiella pneumoniae group and 72.2% in Pseudomonas aeruginosa group and Acinetobacter baumannii group. Using electronic nose, the detection rate in Pseudomonas aeruginosa group and Acinetobacter baumannii group was significantly different from that in Staphylococcus aureus group and Escherichia coli group ( P<0.05). The clinical detection rate of wound pus was 100.0% in Staphylococcus aureus group, Escherichia coli group and Klebsiella pneumoniae group, 94.4% in Pseudomonas aeruginosa group and 66.7% in Acinetobacter baumannii group. The clinical detection rate in Acinetobacter baumannii group differed significantly compared to that in Staphylococcus aureus group, Escherichia coli group and Klebsiella pneumoniae group ( P<0.05), while there was no significant difference between Acinetobacter baumannii group and Pseudomonas aeruginosa group ( P>0.05). Comparison of detection rate of wound pus between electronic nose and clinic examination showed a Kappa coefficient of 0.475. Conclusions:The animal wound pus detected by electronic nose can obtain a feature map with high repeatability compared to the standard bacterial fluid. The electronic nose detection has a medium degree of consistency with clinical detection, providing an experimental basis for the feasibility of using electronic nose to rapidly screen types of pathogenic bacteria.

Characteristics of changes in muscle quality and strength in patients with type 2 diabetes mellitus / 中华老年医学杂志

Objective:To investigate the characteristics of changes in muscle quality and strength in middle-aged and elderly patients with type 2 diabetes mellitus(T2DM).Methods:A total of 670 patients(320 males and 350 females)aged 50 years and over from the endocrinology departments of 9 hospitals in Beijing were recruited as the type 2 diabetes mellitus group(T2DM group)by using systematic random sampling, and 214(54 males and 75 females)age-matched Beijing Hospital retirees without T2DM were randomly enrolled as the control group.Body composition was measured by using bioimpedance analysis.Low muscle mass was defined as appendicular skeletal muscle mass index(ASMI)below 7.18 kg/m 2 in men and 5.73 kg/m 2 in women.Low muscle strength was defined as grip strength below 29.5 kg in men and 21.2 kg in women.Sarcopenia was defined by the presence of low muscle mass with low grip strength.Muscle quality was calculated by grip strength divided by muscle mass of the dominant upper limb, and muscle strength per mass unit was compared.Multivariate Logistic regression was used for correlation analysis. Results:The fasting blood glucose(FPG)level, the waist to hip ratio, the percentages of smokers and drinkers, and the proportions of subjects with concurrent hypertension and coronary heart disease were higher in the T2DM group than in the control group( P<0.05 or 0.01). Compared with the control group, grip strength and muscle quality decreased significantly in male T2DM patients( t=4.408 and 3.972, P<0.01). In male participants, BMI( t=-5.567, 95% CI: -0.375~-0.179, P<0.01)and glycated hemoglobin(HbA1c)( t=-2.322, 95% CI: -0.420~-0.035, P<0.05)were negatively correlated with muscle quality, while old age( OR=1.062, 95% CI: 1.023~1.103, P<0.01; OR=1.074, 95% CI: 1.027~1.122, P<0.01)and increased HbA1c level( OR=1.062, 95% CI: 1.023~1.103, P<0.01; OR=1.074, 95% CI: 1.027~1.122, P<0.01)were risk factors for low muscle strength and sarcopenia. Conclusions:Compared with non-diabetes patients, muscle quality and strength decrease significantly in middle-aged and elderly male T2DM patients.Besides aging, increased levels of HbA1c and BMI are risk factors for low muscle quality and strength.

Analysis of dietary and metabolic characteristics in elderly sarcopenia patients with diabetes mellitus / 中华老年医学杂志

Objective To investigate the metabolic characteristics,body composition and dietary intake in elderly sarcopenia patients with type 2 diabetes(T2DM).Methods A total of 652 T2DM patients(327 males and 325 females)aged over 60 years were selected from endocrinology department of nine different hospitals in Beijing.Body composition was measured by bioimpedance analysis,and the appendicular skeletal mass index(ASMI)was calculated.Sarcopenia was defined as body height-adjusted skeletal muscle mass (ASMI)below the lower quintile of the young reference group.The diagnostic cutoff points for sarcopenia were 7.18 kg/m2 for men and 5.73 kg/m2 for women.All patients were divided into the sarcopenia group versus the control group(below vs.not below 7.18 kg/m2 for men and 5.73 kg/m2 for women).The anthropometric parameters,body composition,biochemical laboratory results and dietary intake were compared between the two groups.The blood glucose target levels were less than 7 mmol/L of fasting plasma glucose(FPG)or less than 7％ of haemoglobin A1c(HbA1c).The obesity ratio was calculated according to body fat percentage more than 25％ in men and more than 30％ in women as obesity.Results There were 116 (17.8％)patients in the sarcopenia group (men/women,82/34),and 536 (82.2 ％) patients in the control group (men/women,245/291).Age was higher in the sarcopenia group than in the control group(t =4.385,P =0.000),and body mass index and waist hip ratio(WHR)were lower in the sarcopenia group than in the control group(t =11.724 and 4.173,P=0.000 and 0.000).FPG[(7.5±2.4) mmol/L vs.(8.5±2.5)mmol/L,t =-3.450,P=0.001]and HbA1c[(7.0±1.6) ％ vs.(8.2± 1.7) ％,t =-5.745,P =0.000] were higher in male sarcopenia group than in male control group.The control rate of FPG (127.0％ or 51.8％ vs.27.0％ or 32.9％,x2=8.817,P=0.003)and HbA1c(131.0％ or 53.5％ vs.23.0％ or 28.0％,x2 =15.934,P=0.000)were lower in the sarcopenia group than in the control group.The red blood cell counts,hemoglobin and serum albumin levels,estimated glomerular filtr ationrate(eGFR)were lower in male sarcopenia group than in the male control group(P＜0.05).eGFR was lower in female sarcopenia group than in female control group(t =4.090,P =0.000).Both in men and women,ASMI,grip power,fatless circumference on upper arm,bone mineral content and basal metabolic rate were lower in the sarcopenia group than in the control group(P＜0.05).The total daily intake of energy,carbohydrate,protein and fat were lower in male sarcopenia group than in male control group(P＜ 0.05).Conclusions Compared with the control group,sarcopenia patients are older with worse glycemic control and lower levels of BMI,WHR,renal function,muscle mass and muscle strength.Sarcopenia patients are more prone to osteoporosis.Furthermore,they have poorer nutritional status with an imbalance of dietary intake.Appropriate increase of protein especially high quality protein intake should be recommended to sarcopenia patients with T2DM.

The Impact of Autocapture Function on the Service life of Cardiac Pacemaker / 昆明医科大学学报

Objective This study aimed to estimate the impact of the threshold of Autocapture algorithm on the pacemaker's service life.Methods Seventy-four patients implanted with VVI pacemaker were retrospectively evaluated.Among them,48 were implanted with pacemaker of autocapture function.Diagnostic data were retrieved from device memory.Pacemaker's service life was estimated according to the working flow and voltage.Results (1) The average working voltage of the control group and the observation group was (2.8 ± 0.4) V and (1.1 ± 0.4)V respectively.The difference was statistically significant;(2) The battery life in the observation group was (12.59 ± 0.55) a,significantly longer than that in the control group (6.74 ± 1.12) a,with an 86.8％ increase of the device's estimated service life (P＜0.05).Conclusion The Autocapture function results in a significant service life of cardiac pacemaker and represents valuable clinical technology.

Development of Terahertz Imaging Technology in the Assessment of Burn Injuries / 生物医学工程学杂志

Terahertz waves have unique properties and advantages, which makes it gain increasing attention and applications in the biomedical field. Burns is a common clinical trauma. Since the water-sensitive and non-destructive characteristics of terahertz, terahertz imaging techniques can be used to detect burns. So far, terahertz imaging technology in the assessment of burn injuries has been developed from ex vivo to in vivo, and high-resolution images can be obtained through the gauzes and plasters. In this paper, we mainly introduces the application of terahertz imaging technology and development in the assessment of burn injuries.

Comparative analysis of two different single orifice laparoscopic surgeries for patent processus vaginalis / 中国综合临床

Objective To investigate the clinical efficacy of two different single orifice laparoscopic surgeries for patent processus vaginalis in children. Methods From August 2013 to June 2015,there were 84 children with patent processus vaginalis in the First Affiliated Hospital of Guangxi University of Science and Technolgy. They were divided into two groups ( A and B ) randomly according to different laparoscopic surgeries. Group A:used ordinary micro?laparoscope, single orifice, and double channel. Group B:used Li Xun nephroscope,single orifice,single channel. Both two groups′ the high ligation of the sheath was performed with the aid of the auxiliary forceps in the mirror under surveillance. The mean unilateral operation time, mean postoperative hospitalization duration,complications and recurrences of two groups were compared. Results All children underwent successful laparoscopic surgery,without transfering to open surgery,and unilateral operation time was (12. 53±3. 22) min for group A,(10. 16±2. 79) min for group B,the difference was significant(P=0. 037). The mean postoperative hospitalization duration was (2. 29±0. 57) d in group A,(2. 25±0. 55) d in group B, the difference was not significant ( P= 0. 671 ) . There was no complication and recurrence in two groups. Conclusion laparoscopic percutaneous extraperitoneal closure use Li Xun nephroscope,single orifice, single channel for children is safe and effective,and it is more convenient and less invasive than the conventional micro?laparoscope.

Metastasis-associated lung adenocarcinoma transcript 1 modulates oral squamous cell carcinoma invasion in vitro and in vivo / 中国肿瘤临床

Objective:To investigate the effect of metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) in modulat-ing the effects of oral squamous cell carcinoma (OSCC) invasion. Methods:Real-time polymerase chain reaction was employed to de-tect the expression of MALAT1 in samples of OSCC post-radical resection, normal oral mucosa samples, and oral squamous cell lines. MALAT1-siRNA was transfected into TSCCa human tongue squamous cell carcinoma cell lines. Cell proliferation was determined by methyl-thiazolyl-tetrazolium reduction assay. Cell migration and invasive ability were evaluated by scratch test and transwell assay. The expression of proteins that regulated invasion and apoptosis were examined using Western blot assay. Immunofluorescence assay was used to detect changes in epithelial-mesenchymal transition (EMT)-associated proteins in the cells. Tumor-bearing nude mouse models were established by subcutaneous implantation of TSCCa cells. Immunohistochemistry was used to detect up-regulation of proliferating cell nuclear antigen (PCNA) and matrix metalloproteinase-2/9 (MMP-2/9). Results:MALAT1 expression was significantly higher in OSCC than in normal tissues (P<0.05). MALAT1 expression was inhibited by transfecting MALAT1-siRNA. After MALAT1 expres-sion was down-regulated in TSCCa cells, proliferation was inhibited and invasion was attenuated, showing significant differences com-pared with the cells transfected with scrambled siRNA and control cells (P<0.05). Expression of N-cadherin and MMP-2/9 were down-regulated in the cells after MALAT1 was knocked down. Tumor growth was significantly slower in the MALAT1-siRNA group than in the control groups. IHC indicated that PCNA and MMP-2/9 expression of tumor tissues were significantly inhibited in MALAT1-siR-NA group. Conclusion:MALAT1 is over-expressed in human OSCC. MALAT1 reduction can inhibit the proliferation and invasion of OSCC cells. Furthermore, MALAT1 may promote OSCC invasion and metastasis by modulating EMT.

Effect of monoamine oxidase inhibitor on the differentiation of malignant glioma cell / 生物医学工程学杂志

To investigate the effect of monoamine oxidase inhibitor tranylcypromine (TCP) on the differentiation of human U251 glioma cells, we treated U251 cells with TCP and/or 100 nmol/L histone deacetylase inhibitor trychostatin A (TSA). The differentiation of U251 cells was observed with inverted microscopy. The cell proliferation and cell cycle distribution were determined by MTT assay and flow cytometry, respectively. Apoptosis was observed by Hoechst 33258 staining. The levels of differentiation-related genes were assessed by real-time PCR and Western blotting. TCP-induced differentiation was characterized by typical morphological changes, inhibition of cellular proliferation, accumulation of cells in the G1 phase of the cell cycle, decreased expression of the pluripotency transcription factors Oct4 and Sox2, and increased expression of glial fibrillary acid protein (GFAP). The combination of TCP and TSA treatment also triggered an over-expression of GFAP. These findings suggest that TCP may induce differentiation of U251 glioma cells, and the differentiation process may be promoted by histone deacetylase inhibitor TSA.

Determination of Sulfadiazine Residues in Pork by Molecular Imprinted Column Coupling with High Performance Liquid Chromatography / 分析化学

A method for the quantitative monitoring of sulfadiazine (SD) residues in pork was established by molecular imprinted column coupling with high performance liquid chromatography (HPLC).The molecular imprinted column was selected as an extraction device.To obtain the optimum extraction efficiency,several parameters related to the molecular imprinted column,including column solvent,flow-rate,eluent of the sample matrix and eluent volume,were investigated.The sample solution was directly injected into the device for the extraction after simple extraction.Under the optimum conditions,the relative standard deviations (RSD) was ≤6.1％ and the recoveries for SD were higher than 75.6％.In comparison with the AL-SPE column,the MIP-SPE column had good reusability and extraction efficiency.This method was successfully applied to the determination snlfadiazine residues in pork.

Culture and induced multilineage differentiation of mesenchymal stem cells derived from human nasal mucosa / 临床耳鼻咽喉头颈外科杂志

OBJECTIVE@#To establish an in vitro method to culture mesenchymal stem cells(MSCs) derived from human nasal mucosa, and explore their stemness and differentiation potential.@*METHOD@#Based on the observation of distribution of MSCs in human nasal mucosa, we cultured and proliferated MSCs in vitro and identified the expression of stem cell markers on them including Nestin, CD133, Vimentin and Sa114 with immunofluorescence. The MSCs were induced to differentiate to osteoblasts with medium containing dexamethasone, ascorbic acid and beta sodium glycerophosphate, and to neurons with Neurobasal medium containing B27, ATRA and TSA. Histochemistry and immunofluorescence were applied to evaluate the differentiation.@*RESULT@#The nestin and vimentin immunofluorescence-positive MSCs existed extensively in human nasal mucosa. While the MSCs were cultured in the osteogenic-inducing medium, activities of alkaline phosphatase were increased significantly, and bone nodules were found on the surface of the osteoblasts by alizarin red staining. After the induction by neural-inducing medium, the MSCs adopted neuron like appearance with many slim protrusions interconnected as a network. The induced cells expressed neural markers NF-200 and BM88 strongly.@*CONCLUSION@#The MSCs derived from human nasal mucosa are multipotent stem cells and can be utilized as seed cells to repair bone or neural injury.

Study on clinico-histopathological changes of non-alcoholic fatty liver disease in elderly male patients with type 2 diabetes mellitus / 中华老年医学杂志

Objective To observe the incidence rate of non-alcoholic fatty liver disease (NAFLD) in elderly male patients with type 2 diabetes mellitus (T2DM) and the features of pathological changes of liver. Methods The 89 cases with T2DM (T2DM group) and contemporary non-diabetic cases (control group, n=48) from 858 autopsy samples matched for gender and age were selected in the study. The histopathological changes of liver were observed by microscopy,histochemistry and immunohistochemistry. Results The incidence rates of NAFLD and nonalcoholic steatohepatitis(NASH) were 49.4% (44/89) and 14.6% (13/89) in T2DM group, 22.9 %(11/48) and 4.2% (2/48) in control group, respectively. The incidence rates of NAFLD and NASH were significantly higher in T2DM group than in control group(P＜0.01, P＜0.05). All of the NASH patients from T2DM group and one patient from control group were complicated with different stages of liver fibrosis. One patient from T2DM group was diagnosed as cirrhosis, no cirrhosis patient was found in control group. Conclusions Compared with control group, the incidence rate of NAFLD is higher and the damage of liver is more severe in T2DM group. The ratio of the progress from NAFLD to liver cirrhosis is low.

Development of practicality of EEG-based brain-computer interface / 生物医学工程学杂志

Brain-computer interface (BCI) is a system that can create direct connection between brain activity and external devices. In the past 20 years, important' achievements of research on BCI have been made. Now there are lots of research methods based on electroencephalic signals, and researchers are trying to make the BCI system possess the characteristics of real-time and become more natural and practical. This paper presents an overview of real-time and stimulating way to EEG-based BCI research. Through the discussions on the applications of DSP in BCI system, in signal preprocessing and in algorithm optimization, the high lights in real-time research are pointed out. In the discussions about the way to produce EEG signals in BCI, the researchers suggested that the imaging movement be the most ideal way in that it will reduce the discomfort in stimulation by application of the virtual reality technology in BCI system, thus it will be conducive to improvement in the performance of BCI system.

Design of a Brain-computer Interface System Based on Labview and VC / 中国医学物理学杂志

Objective:Labview and VC were used to design software based on the Active One biopotential measurement system to realize the visual evoked potential based brain-computer interface.Methods:The data acquisition software was designed by Labview,the human-interface,real time signal processing and dynamic link library software were designed by VC.Data transmission between Labview and VC was realized through the dynamic link library using shared memory technology.The multimedia timer,DirectDraw technology and parallel port data output were used to design the visual stimulation interface.The 5 points averaging filter combining with averaging method were used to detect the visual evoked potential and the correlation coefficient was computed for signal recognization.Results:The experiments showed that the visual stimulator can produce effective visual stimulation.The data transmission method using the dynamic link library can satisfy the requirement of the system.Conclusions:The real-time signal processing method can improve signal-noise ratio and realize detection and recognization of visual evoked potential.The system can determine which module the subject was fixating and the result was feedback to the subject in real time.

Study on histopathological changes of hepatic portal area in elderly men with type 2 diabetes mellitus / 中华老年医学杂志

Objective To study the histopathological features of hepatic portal area in autopsy specimens of elderly men with type 2 diabetes mellitus (T2DM).Methods One hundred and three autopsy cases with T2DM (diabetic group) and contemporary 48 non-diabetic cases matched by gender and age (control group) were selected in the study.The histopathological changes of hepatic portal area were observed by histochemical and immunohistochemical methods.Results (1) In diabetic group, endothelial denudation, eosinophilie deposits, eccentric intimal thickening and luminal stenosis were found in hepatic interlobular artery (arteriole, the lumen diameter < 100 μm).The medial smooth muscle cells proliferated and migrated into intima, and fibroplasia occurred in adventitia.62.1% (64/103) of the patients with T2DM had microangiopathy and there was statistically significant difference between the two groups (χ2= 27.14, P< 0.01 ).(2) Hyaline collagen fiber tissues deposited around interlobular artery, interlobular vein and interlobular bile ducts, resulting in enlargement of the portal area and the secondary atrophy and disappearance of portal triad.65.0% (67/103) of the patients with T2DM had this pathological changes in the portal area and there was statistically significant difference between the two groups(χ2= 23.27,P<0.01).(3) Terminal portal area was notable.Conclusions Mieroangiopathy can be observed in the hepatic portal areas of elderly men with T2DM, which may induce the fibrotic tissue hyperplasia, the atrophy of the portal triad and the sclerosing portal area.

Analysis and research of brain-computer interface experiments for imaging left-right hands movement / 生物医学工程学杂志

This is a research carried out to explore a pragmatic way of BCI based imaging movement, i. e. to extract the feature of EEG for reflecting different thinking by searching suitable methods of signal extraction and recognition algorithm processing, to boost the recognition rate of communication for BCI system, and finally to establish a substantial theory and experimental support for BCI application. In this paper, different mental tasks for imaging left-right hands movement from 6 subjects were studied in three different time sections (hint keying at 2s, 1s and 0s after appearance of arrow). Then we used wavelet analysis and Feed-forward Back-propagation Neural Network (BP-NN) method for processing and analyzing the experimental data of off-line. Delay time delta t2, delta t1 and delta t0 for all subjects in the three different time sections were analyzed. There was significant difference between delta to and delta t2 or delta t1 (P<0.05), but no significant difference was noted between delta t2 and delta t1 (P>0.05). The average results of recognition rate were 65%, 86.67% and 72%, respectively. There were obviously different features for imaging left-right hands movement about 0.5-1s before actual movement; these features displayed significant difference. We got higher recognition rate of communication under the hint keying at about 1s after the appearance of arrow. These showed the feasibility of using the feature signals extracted from the project as the external control signals for BCI system, and demon strated that the project provided new ideas and methods for feature extraction and classification of mental tasks for BCI.

Progress in the research of neural interface technology / 生物医学工程学杂志

Neural interface technology researches, which constitute the intercross science relating to neurophysiology, computational science, microelectronic technology and so on, are of important value in rehabilitation engineering. In this paper, the concept and significance of neural interface were introduced. The applications and methods of different kinds of neural interface system were expounded. Related animal experiments were citated. The recent studies and trends in neural interface technology were also discussed.

Vascularization of methl-methacrylate modified polymerized 2-hydroxyethyl methacryate hydrogel orbital implant / 中国组织工程研究

BACKGROUND: The application of polymerized 2-hydroxyethyl methacryate (PHEMA) in many organs of living body shows good biocompatibility.OBJECTIVE: To observe the biocompatibility and fibrovascular condition of methl-methacrylate (MMA) modified PHEMA hydrogel orbital implant.DESIGN: Single sample observation.SETTING: Department of Ophthalmology, the General Hospital of Chinese PLA; Institute of Polymer Science,Department of Chemical Engineering, Tinghua university.MATERIALS: Twenty-five New Zealand rabbits of either gender and clean grade, weighing 2.0 to 2.5 kg, were provided by the Animal Experimental Center, General Hospital of Chinese PLA. The animals were observed at postoperative 2, 4,8, 12 and 24 weeks, 5 at each time point. The experiment was permitted by ethics committee. MMA modified PHEMA hydrogel orbital implant was provided by Institute of Polymer Research, Department of Chemical Engineering, Tinghua University. The experiment was permitted by ethics committee.METHODS: This experiment was carried out in the laboratory of Department of Ophthalmology, the General Hospital of Chinese PLA from March to October 2003. The right eye served as operation eye. When the rabbits were anesthetized,their eyelids were open with eyelid retractor. Bulbar conjunctiva was open along the edge of limbus of cornea for isolating fascia. Oculorotatory muscle was isolated and pre-set suture line was made, then muscle was cut off. When optical nerve was cut off, eyeball was completely excised. A MMA modified PHEMA hydrogel orbital implant with the diameter of 14 mm was implanted into the fossa orbitalis of rabbits. Single photon emission computed tomography (SPECT) was performed at postoperative 2, 4, 8, 12 and 24 weeks. The hydrogel orbital implant was taken out at postoperative 2, 4, 8,12 and 24 weeks for light microscope, immunohistochemical and electron microscope examinations.MAIN OUTCOME MEASURES: Vascularization of hydrogel orbital implant was observed in vivo by isotope tracing observation at different time points. Vascularization of hydrogel orbital implant was observed ex vivo by light microscope,immunohistochemical and electron microscope observations.RESULTS: All 25 New Zealand rabbits were involved in the final analysis. ①SPECT examination showed that isotope increased around the implants at week 2, and extended gradually at weeks 4 and 8. The radiotracer accumulated evenly in the implants from surrounding to the center at week 12. ②Light microscopic examination of the prostheses revealed fiber vessels grew from the surrounding to the center. At week 2,fibrovascular tissue grew in the hole of implant. Long or round cells with deeply dyed nucleuses were found in the hole, being fibroblasts. The vascular structure in the hole of the implant was clear, and vascular wall and blood cells were found. The inflammatory cells were mainly neutrophils and lymphocytes, and occasionally large macrophages. ③Scanning electron microscope showed that fibrovascular tissue grew in the hole of the implant, and was dense and intercrossed at week 12. ④ Conjunctiva split appeared postoperatively in 1 of 25 cases, and healed well after two times of operation. Conjunctival congestion lessened and conjunctiva healed within postoperative 7 days in the remaining 24 animals.CONCLUSION: MMA modified PHEMA hydrogel orbital implant has good histocompatibility and fast vascularization process, and is easy to be operated with fewer complications. So, it is a safe and practicable new type orbital implant.

Application of active electrode in the surface electromyogram detection / 中国组织工程研究

AIM: To detect surface electromyogram (EMG) signal accurately.METHODS: How to reduce noise in the detection of surface EMG signal was discussed. It has been explored to design an electrode unit by using methods of differential amplification, active electrode, filter and so on , andto investigate the electrode shape and the right placing method.RESULTS: The instrumentation amplifier AD620 was adopted to design a bipolar active electrode, which has been successfully used in the surface EMG detection.CONCLUSION: Experiments show that using active electrode can improve ratio of signal and noise, reduce noise and detect surface EMG signal effectively.

Rule of neuron development in transplanted retina and the significance of its regeneration and plasticity / 中国组织工程研究

BACKGROUND: As indicated by transplantation experiments in recent years, correlative neural active substances could be synthesized in the transplanted retina(TP); however, the growth and development situation of neural active substance positive neurons in TP is unclear.OBJECTIVE: To observe the differentiation and development of the neuron,and the biosynthesis of neural active substance in TP and its relationship with environment and visual center to explore the rule of development of nerve tissue and its regeneration and plasticity.DESIGN: An observatory comparative study based on animals.SETTING: Department of histology and embryology of two universities.MATERIALS: The study was conducted in the Experimental Animal Center of Guangzhou Medical College between August 2002 and March 2003. Totally 96 healthy SD rats in either gender were selected.INTERVENTIONS: Embryonal 14-day SD retina was transplantedin-between the epithalamus and hypothalamus of the midbrain in P1 rat and the right eye of the P1 rat was removed simultaneously. The development time of TP on the 9th day after operation was corresponding to the normal retina on the 1st day after born, which was then recorded as TP1, and so on. The development and differentiation was shown by histochemical method.MAIN OUTCOME MEASURES: Development and morphological observation of TP and neurons in TP.RESULTS: TP had the same structure of each layer as normal retina and its similar growth and development rule, which also could synthesize relative neural active substance. Nitricoxide synthase(NOS) -positive neuron in TP started at TP4 and reached its peak at TP12, but the number of positive neurons was kept on a relative low level after TP22.CONCLUSION: Embryonal retina could survive and remain its original growth and development rule after intracerebral transplantation, which has same structural characters as normal retina.