Biomedical subjects

Q Shen

Publications and source records attributed to Q Shen.

At least 91 records · Page 5Linked to original sources

PubMed1998

Induction of transforming growth factor beta 1 by insulin-like growth factor-1 in dermal fibroblasts.

Transforming growth factor beta1 (TGF-beta1) belongs to a family of multifunctional modulatory proteins involved in cell growth, differentiation, development, and wound healing. Although the biological activities of TGF-beta1 have been extensively studied, its regulation remains obscure. Here we report the effects of insulin-like growth factor-1 (IGF-1) on the expression of TGF-beta1 by dermal fibroblasts and suggest a possible mechanism. An enzyme-linked immunosorbent assay (ELISA) specific for TGF-beta revealed a greater than twofold increase (12.3 +/- 1.6 vs. 4.8 +/- 0.8 pg/10(4) cells, n = 7, P < 0.05) in the protein in conditioned medium obtained from IGF-1-treated cells compared to that from untreated controls. Similar results were obtained by the mink lung epithelial cell growth inhibition assay. The results of Northern analysis revealed a dose-dependent increase in TGF-beta1 mRNA in response to IGF-1 treatment. Using the optimum concentration of IGF-1 (100 ng/ml), a greater than twofold increase (25.43 +/- 5.7 vs. 12.13 +/- 4.5, P < 0.05) in TGF-beta1 mRNA was observed. This effect persisted for at least 48 h after IGF-1 was removed from the culture medium. Nuclear run-on assay showed that this stimulation was due, at least in part, to an increase in the rate of transcription of the TGF-beta1 gene. Treatment of human dermal fibroblasts with IGF-1 caused a substantial increase in c-fos and c-jun mRNA expression within 30 and 60 min, respectively. In contrast to c-jun mRNA which was constitutively expressed by dermal fibroblasts, the expression of c-fos mRNA was transient and only detectable between 15 and 60 min. Greater than 58% of the increase in TGF-beta1 caused by IGF-1 could be blocked by the addition of anti-TGF-beta1 neutralizing antibody to the culture medium, suggesting that autoinduction of TGF-beta1 may be involved. An increase in IGF-1-induced TGF-beta1 should be important in many different physiological processes such as cellular proliferation, differentiation, and wound healing. These findings also suggest that induction of TGF-beta1 mRNA and protein by IGF-1 may be a mechanism by which this cytokine is regulated in physiological and/or pathological conditions.

Animals↗

PubMed1998

Genetically modified dermal keratinocytes express high levels of transforming growth factor-beta1.

In an attempt to genetically modify cultured keratinocytes with transforming growth factor-beta1 (TGF-beta1), which has been proven to be one of the most important cytokines involved in wound healing, two constructs were made. One, designated pG3Z:K14-TGF-beta1, is a plasmid in which the expression of TGF-beta1 is driven by the keratin 14 promoter. The other, designated pLin-TGF-beta1, is a retroviral vector in which the retroviral 5' long-terminal repeat promoter drives expression. In both constructs, the deletion of a small fragment of the noncoding region of the TGF-beta1 gene was made to differentiate the transcript from that for endogenously expressed TGF-beta1. Different types of cells were transfected with the pG3Z:K14-TGF-beta1 construct using the calcium phosphate method. The pLin-TGF-beta1 construct was propagated in a retroviral packaging cell line and conditioned medium that contained high titers of the virus was used to transduce keratinocytes or other types of cells grown in standard culture. Northern analysis, used to evaluate the expression of TGF-beta1 mRNA in the pG3Z:K14-TGF-beta1 transfected keratinocyte C1-177 cell line, showed a smaller TGF-beta1 transcript compared with that endogenously expressed by dermal fibroblasts. The level of TGF-beta1 protein evaluated by enzyme-linked immunosorbent assay was significantly higher in medium conditioned by either the K14-TGF-beta1 transfected or the pLin-TGF-beta1 transduced keratinocytes, compared with that obtained from control cells; however, the level of TGF-beta1 protein was unchanged in cultures of pG3Z:K14-TGF-beta1 transfected nonkeratinocyte cells such as fetal and adult fibroblasts. Using the mink lung epithelial cell growth inhibition assay, we found an increase in TGF-beta1 activity in conditioned medium from the pG3Z:K14-TGF-beta1 transfected cells. To evaluate possible paracrine effects of the keratinocyte derived TGF-beta1, a coculture system was established with pLin-TGF-beta1 transduced keratinocytes grown in the upper chamber and dermal fibroblasts in the lower chamber. The results showed that TGF-beta1 released from keratinocytes diffused to the lower chamber where it stimulated collagen production by dermal fibroblasts. In summary, we demonstrate here that primary cultured keratinocytes can be genetically modified to express high levels of TGF-beta1 and suggest that this offers a potential approach for the therapy of dermal lesions such as nonhealing wounds.

Cells, Cultured↗

PubMed1998

IFN-alpha2b suppresses the fibrogenic effects of insulin-like growth factor-1 in dermal fibroblasts.

The interferon (IFN) proteins, including IFN-alpha2b have been used as antifibrogenic factors to modulate the expression of extracellular matrix (ECM) proteins associated with fibroproliferative disorders in skin. This study was conducted to determine if IFN-alpha2b can counteract the fibrogenic effects of insulin-like growth factor-1 (IGF-1), which is present in large quantity in fibrotic dermis. Human dermal fibroblasts were established in culture and treated with either vehicle (control), 2000 U/ml IFN-alpha2b alone, 100 ng/ml IGF-1 alone, or both IFN-alpha2b and IGF-1. The results showed that treatment with IFN-alpha2b inhibited the proliferation of dermal fibroblasts, reduced the steady-state levels of type I procollagen mRNA in the cells, and reduced the production of collagen as measured by hydroxyproline in conditioned medium. However, this treatment also increased levels of collagenase mRNA in the cells and collagenase activity in the medium. Cells treated with IGF-1 showed increased proliferation and collagen production and decreased collagenase. Cells treated with both IFN-alpha2b and IGF-1 exhibited a 44% reduction in hydroxyproline production (p < 0.05) and a 363% increase in collagenase activity over cells treated with IGF-1 alone (p < 0.01). These results indicate that when IGF-1 and IFN-alpha2b are used individually, they function as fibrogenic and antifibrogenic factors for dermal fibroblasts, respectively, and that fibrogenic effects of IGF-1 on cell proliferation, collagen, and collagenase expression can be counteracted by IFN-alpha2b. These findings support the potential use of IFN-alpha2b as a therapeutic agent for treatment of fibroproliferative disorders, such as postburn hypertrophic scarring.

Cell Division↗

PubMed1998

Dehydration-stress-regulated transgene expression in stably transformed rice plants

To confer abscisic acid (ABA) and/or stress-inducible gene expression, an ABA-response complex (ABRC1) from the barley (Hordeum vulgare L.) HVA22 gene was fused to four different lengths of the 5' region from the rice (Oryza sativa L.) Act1 gene. Transient assay of beta-glucuronidase (GUS) activity in barley aleurone cells shows that, coupled with ABRC1, the shortest minimal promoter (Act1-100P) gives both the greatest induction and the highest level of absolute activity following ABA treatment. Two plasmids with one or four copies of ABRC1 combined with the same Act1-100P and HVA22(I) of barley HVA22 were constructed and used for stable expression of uidA in transgenic rice plants. Three Southern blot-positive lines with the correct hybridization pattern for each construct were obtained. Northern analysis indicated that uidA expression is induced by ABA, water-deficit, and NaCl treatments. GUS activity assays in the transgenic plants confirmed that the induction of GUS activity varies from 3- to 8-fold with different treatments or in different rice tissues, and that transgenic rice plants harboring four copies of ABRC1 show 50% to 200% higher absolute GUS activity both before and after treatments than those with one copy of ABRC1.

Journal Article↗

PubMed1998

A preliminary study of the mental health of young migrant workers in Shenzhen.

The aim of this study is to examine the mental health status of young migrant workers in Shenzhen. Using the Symptoms Check List-90 (SCL-90), Eysenck Personality Questionnaire, Social Support Scale and Mental Health Questionnaire for Laborers, 371 migrant workers who came from inland areas of China and 100 local workers were investigated. The SCL-90 profile of migrant workers was also compared to the SCL-90 norms provided by general people in China. The SCL-90 results showed that the total scores, the average scores of the positive symptoms, the three factor scores of obsessionality, interpersonal sensitivity and phobia in migrant workers were significantly higher than those in the local workers. According to the multivariate analysis, the amount of contribution to mental health, in descending order, was neuroticism, psychological pressure, income, home sickness, marital or love problems, extroversion and introversion, living conditions and social status. The mental health status of young migrant workers in Shenzhen was poorer than that of their local counterparts, as well as people in China on the SCL-90. It is recommended that mental health workers should help migrant workers adjust to the new urban environment by providing psychological counseling and other relevant treatment facilities.

Acculturation↗

PubMed1998

Comparison of schizophrenic patients' families and normal families in China, using Chinese versions of FACES-II and the Family Environment Scales.

The lack of measures that systematically evaluate the characteristics and functioning of Chinese families is hindering the development of appropriate family interventions for schizophrenia in China. We assessed the reliability and validity of revised and adapted Chinese versions (CV) of the Family Adaptability and Cohesion Evaluation Scales (FACES-II-CV) and the Family Environment Scales (FES-CV) and administered these instruments to 120 respondents from families with a schizophrenic member and 126 respondents from control families. The psychometric properties of the FACES-II-CV and of the FES-CV Cohesion, Conflict, Intellectual-Cultural Orientation, and Active-Recreational Orientation scales are satisfactory, so they are appropriate for use in China; the remaining six FES-CV scales require further culturally appropriate revision. Compared to control families, families with schizophrenic patients in China have higher conflict, lower cohesion, poor adaptability, and are less likely to be involved in intellectual and recreational activities. These differences remained significant after adjusting for family and respondent characteristics.

Adaptation, Psychological↗

PubMed1998

Intrinsic programs of patterned cell lineages in isolated vertebrate CNS ventricular zone cells.

Using long-term, time-lapse video-microscopy, we investigated how single progenitor cells isolated from the early embryonic cerebral cortex produce neurons and glia over time. Clones of 10 cells or less were produced by short symmetric or asymmetric division patterns, commonly terminating in a 'pair progenitor' for two morphologically identical neurons. Larger trees were composites of these short sub-lineages: more prolific neuroblasts underwent repeated asymmetric divisions, each producing a minor neuroblast that typically made (3/4)10 progeny, and a sister cell capable of generating more progeny. Particular division patterns were seen repeatedly. In contrast, glioblasts underwent a prolonged series of symmetric divisions. These patterned lineage trees were generated from isolated cells growing on plastic, suggesting they are largely intrinsically programmed. Our data demonstrate for the first time that CNS progenitor cells have stereotyped division patterns, and suggest that as in invertebrates, these may play a role in neural development.

Animals↗

PubMed1998

Solitary bone cyst in the odontoid process and body of the axis. A case report and review of literature.

A four-year-old boy presented with a solitary bone cyst in the odontoid process and body of the axis. Plain radiographs showed a radiolucent lesion with extreme thinning of the cortex and MRI demonstrated a high signal intensity in the interlesional matrix. The cystic component extended into the body of the axis through a defect in the epiphyseal plate. At operation, the cavity of the cyst was found to contain serosanguineous fluid, and histological examination showed that it was lined by a thin layer of connective tissue. The cyst may have originated from a defect in the epiphyseal plate.

Bone Cysts↗

PubMed1998

Cloning of 1-aminocyclopropane-1-carboxylate (ACC) synthetase cDNA and the inhibition of fruit ripening by its antisense RNA in transgenic tomato plants.

A 1.7 kb fragment of ACC synthetase cDNA, one member of the ACC synthetase multigene family, was amplified from total tomato cDNA through a polymerase chain reaction (PCR) and cloned in E. coli. Restriction mapping and sequencing analysis confirmed its fidelity and correctness. The cloned ACC synthetase gene was then inserted into a binary vector pBin437, in an inverted orientation between the CaMV 35S promoter with duplicated enhancers and the Nos 3' transcriptional termination sequence, to construct an expression vector pBACC. Transgenic tomato plants were obtained by A. tumefaciens-mediated transformation of cotyledons. PCR detection and Southern blot analysis confirmed the integration of the antisense ACC synthetase gene in the transformed tomato genome. The results from RT-PCR of RNAs isolated from transgenic tomato leaves confirmed that antisense ACC synthetase RNA was synthesized in these transgenic plants. The amount of ethylene released from transgenic tomato fruits was reduced significantly to about 30% of that released by non-transformed controls. The inhibition effect of antisense RNA on fruit ripening was observed in transgenic plants and their progeny (T1). The shelf life of transgenic tomato fruits was at least 60 days at room temperature without significant change in hardness and color. After 15-20 days of treatment of the transgenic fruits with ethylene, most of them reached the ripe stage. The antisense ACC synthetase gene was inherited as a single gene in the progenies of transgenic tomatoes determined by T1 progeny analysis, consistent with the results of Southern blot analysis. Transgenic homozygotes expressing antisense ACC synthetase RNA showed prolonged shelf life in the T2 progeny.

Cloning, Molecular↗

PubMed1998

Expression of human interleukin 12 (hIL-12) in insect cells.

Human interleukin-12(hIL-12) is a herterodimer cytokine, which consists of two disulfide-linked subunits, p40 and p35. This paper reports the expression of hIL-12 using the Baculovirus Expression System in insect cells. First, we constructed two expression vectors pVL1392-hp40 and pVL1393-hp35, and then they were used to co-transfect the insect cells (Sf9) separately with linearized polyhedrosis virus genomic DNA. Two kinds of recombinant viruses AcNPV-hp40 and AcNPV-hp35 were visually screened out. Biological activity of the recombinant hIL-12 (rhIL-12) was detected in the conditioned medium using proliferation assay of PHA-activated human lymphocytes and the expression level was about 1.5 approximately 2 microg/10(6) cells. The results of real-time Biomolecular Interaction Analysis (BIA) and Northern blot demonstrated that the subunits of rhIL-12, hp35, and hp40 were expressed successfully in the insect cells. The apparent molecular weights of rhIL-12 and hp40 homodimer were 76 kDa and 92 kDa under non-reducing conditions of Western blot, respectively. The recombinant hp40 can significantly inhibit the biological activity of hIL-12.

Animals↗

PubMed1998

The purification and identification of heme oxygenase isoforms from spleen tissue of rat and the expression of heme oxygenase-1 cDNA in COS-1 cells.

OBJECTIVE: To demonstrate that heme oxygenase (HO) isoforms exist in rat spleen treated with hematin and phenylhydrazine and to confirm that the isolated cDNA actually encodes HO-1 by expressing cDNA in monkey kidney cells (COS-1 cells) in order to prepare HO-1 mutant for inhibiting the natural enzyme. METHODS: The rat spleen microsomal fractions were first purified by diethylaminoethyl (DEAE)-Sephacel and hydroxylapatite. The activity of two isoforms (HO-1 and HO-2) of enzyme and their apparent molecular weight on sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (SDS-PAGE) were measured. Secondly, using the isolated HO-1 cDNA clone, the expression plasmid pcDNA3HO1 was constructed and transfected into cultured COS-1 cells. The transfected cells were collected and disrupted by sonication, and the microsomes were prepared by ultracentrifugation. The activity of HO-1 was measured. RESULTS: Two isoforms were purified and identified in treated rat spleen and HO-1 was the predominant form. The ratio of HO-1 to HO-2 was 3.2:1. The apparent molecular weights of HO-1 and HO-2 were about 30 kD and 36 kD under reducing conditions, respectively. The HO-1 was highly expressed in endoplasmic reticulum of transfected cells. The specific band was located in molecular weight of 30 kD. The specific activity was five times higher than that of the control. CONCLUSION: The activity of expressed HO-1 in COS-1 cells is higher than that of purified enzyme from rat spleen tissue. It is suggested that this clone having an insert of 1030 base-pairs encodes HO-1 and that we can prepare HO-1 mutant by site-directed mutagenesis of HO-1 cDNA to prevent and treat hyperbilirubinemia.

Animals↗

PubMed1998

[Simulation study of selectively stimulating nerve fibers using biphasic pulses].

Biphasic selective stimulation is an effective electrical stimulation mode for preventing nerve fibers against electrochemical damage, for muscle to contract smoothly, and decreasing muscle's fatigue. By use of computer simulation, this paper presents three biphasic stimulation modes respectively using monopolr, bipolar and tripolar electrodes, which can effectively stimulate nerve fibers in a selective way. The results are helpful to the clinical application of neuroelectrical stimulation.

Computer Simulation↗

PubMed1998

Stem cells in the embryonic cerebral cortex: their role in histogenesis and patterning.

The cytoarchitectural simplicity of the cerebral cortex makes it an attractive system to study central nervous system (CNS) histogenesis--the process whereby diverse cells are generated in the right numbers at the appropriate place and time. Recently, multipotent stem cells have been implicated in this process, as progenitor cells for diverse types of cortical neurons and glia. Continuous analysis of stem cell clone development reveals stereotyped division patterns within their lineage trees, highly reminiscent of neural lineage trees in arthropods and Caenorhabditis elegans. Given that these division patterns play a critical part in generating diverse neural types in invertebrates, we speculate that they play a similar role in the cortex. Because stereotyped lineage trees can be observed from cells growing at clonal density, cell-intrinsic factors are likely to have a key role in stem cell behavior. Cortical stem cells also respond to environmental signals to alter the types of cells they generate, providing the means for feedback regulation on the germinal zone. Evidence is accumulating that cortical stem cells, influenced by intrinsic programs and environmental signals, actually change with development-for example, by reducing the number and types of neurons they produce. Age-related changes in the stem cell population may have a critical role in orchestrating development; whether these cells truly self-renew is a point of discussion. In summary, we propose that cortical stem cells are the focus of regulatory mechanisms central to the development of the cortical cytoarchitecture.

Animals↗

PubMed1997

Molecular cloning of a cDNA encoding the neuropeptides APGWamide and cerebral peptide 1: localization of APGWamide-like immunoreactivity in the central nervous system and male reproductive organs of Aplysia.

While much is known about the neural and endocrine mechanisms that control egg laying in the gastropod mollusk Aplysia, relatively little is known about the regulation of male reproductive activity in this simultaneous hermaphrodite. In the present study, we have cloned and sequenced a cDNA that encodes a precursor protein, the predicted posttranslational processing of which presumably generates nine copies of the neuropeptide Ala-Pro-Gly-Trp-NH2 (APGWamide), five connecting peptide sequences, and a C-terminal peptide. The sequence of one connecting peptide is identical to the previously characterized cerebral peptide 1. Northern blot analysis identified two major APGWamide mRNA transcripts (approximately 1.3 kb, approximately 2.4 kb), which were present in central nervous system ganglia, but were most abundant in the right cerebral and right pedal ganglia. Immunohistochemical studies using sexually mature Aplysia demonstrated that the vast majority of APGWamide-like immunoreactivity was localized in 30-40 neurons along the anterior and medial margins of the right cerebral ganglion and in a cluster of 15-20 neurons in the right pedal ganglion. A total of only about ten immunoreactive neurons were located in other ganglia. Immunohistochemistry also demonstrated that APGWamide was present in the reproductive organs that participate in the storage or transport of sperm, including the small hermaphroditic duct (site of sperm storage before mating), the white hemiduct (also known as the copulatory duct), and penial complex. As a group, these data suggest that APGWamide may play a role in regulating male reproductive function in Aplysia, as it does in other gastropods.

Amino Acid Sequence↗

PubMed1997

Expression of high-mobility group-1 mRNA in human gastrointestinal adenocarcinoma and corresponding non-cancerous mucosa.

An 1194-nucleotide complementary DNA clone, FM1, encoding a human high-mobility group-1 protein (HMG-1) was isolated from a well-differentiated human gastric-carcinoma cell line complementary DNA library by a differential screening method. FM1 is similar to the published human HMG-1 in mature protein, with only 3 different codons at positions 11, 149, and 190. We analyzed 33 gastric and colorectal adenocarcinomas for expression of the FM1 gene. Northern-blot analysis revealed that all of the cancers expressed FM1 at a higher level than in corresponding non-cancerous mucosa, with 2 transcripts of approximately 1.4 and 2.4 kilobases. The FM1 expression level in the non-cancerous tissues increased with the depth of accompanying cancer invasion. Only 18.2% of well-differentiated cancers showed a higher expression level in corresponding non-cancerous tissues, whereas the expression in corresponding non-cancerous tissues was significantly higher in moderately (60%) and poorly differentiated (83.3%) cancers. In situ hybridization demonstrated the location of FM1 mRNA in well- and poorly differentiated gastric-cancer cells as well as in non-cancerous tissue adjacent to poorly differentiated gastric cancer, but no hybridization was detected in normal epithelial cells adjacent to well-differentiated gastric cancer. These findings may provide new information on HMG-1 mRNA expression in human gastrointestinal cancer and suggest a correlation between FM1 mRNA expression to the differentiation and the stage of human gastrointestinal adenocarcinomas.

Aged↗

PubMed1997

The BCL-6 proto-oncogene controls germinal-centre formation and Th2-type inflammation.

Structural alterations of the promoter region of the BCL-6 proto-oncogene represent the most frequent genetic alteration associated with non-Hodgkin lymphoma, a malignancy often deriving from germinal-centre B cells. The BCL-6 gene encodes a zinc-finger transcriptional repressor normally expressed in both B cells and CD4+ T cells within germinal centres, but its precise function is unknown. We show that mice deficient in BCL-6 displayed normal B-cell, T-cell and lymphoid-organ development but have a selective defect in T-cell-dependent antibody responses. This defect included a complete lack of affinity maturation and was due to the inability of follicular B cells to proliferate and form germinal centres. In addition, BCL-6-deficient mice developed an inflammatory response in multiple organs characterized by infiltrations of eosinophils and IgE-bearing B lymphocytes typical of a Th2-mediated hyperimmune response. Thus, BCL-6 functions as a transcriptional switch that controls germinal centre formation and may also modulate specific T-cell-mediated responses. Altered expression of BCL-6 in lymphoma represents a deregulation of the pathway normally leading to B cell proliferation and germinal centre formation.

Animals↗

PubMed1997

Liposome-associated interferon-alpha-2b functions as an anti-fibrogenic factor for human dermal fibroblasts.

This study was conducted to determine whether interferon-alpha-2b (IFN-alpha-2b) can be encapsulated in liposomes without compromising its anti-fibrogenic effects on human dermal fibroblasts. The rationale for this approach is that systemic administration of IFN-alpha-2b by injection for treatment of dermal fibrosis is uncomfortable, requires a large quantity of the cytokine, and cannot be easily used in children. Liposomes are potentially useful as vehicles for the topical delivery of drugs if they can be encapsulated without loss of biologic activity. Empty sonicated vesicles composed of dioleoyl-phosphatidylcholine:dioleoyl-phosphatidylglycerol at a molar ratio of 7:3 were mixed with various concentrations of IFN-alpha-2b and then dried and rehydrated. An enzyme-linked immunosorbent assay (ELISA) was used to determine the efficiency of encapsulation and the stability of the preparation under experimental conditions. Greater than 80% of added IFN-alpha-2b became associated with the liposomes and remained encapsulated for up to 5 d at 4 degrees C. The rate of release increased markedly at 37 degrees C. Liposome-encapsulated IFN-alpha-2b (2000 units per ml) significantly reduced the proliferation of dermal fibroblasts (60 +/- 8.8 vs. 100 +/- 8, mean +/- SEM, p < 0.05, n = 8) and the levels of mRNA for type I (41.5 +/- 8.7% vs 100 +/- 18, p < 0.05, n = 4) and type III (68 +/- 8.4% vs 100 +/- 4.9%, p < 0.05, n = 3) procollagen, as analyzed on northern blots. This was consistent with the reduction found in collagen in conditioned medium from treated fibroblasts. In contrast, treatment increased levels of mRNA for collagenase (241 +/- 42% vs 100 +/- 3.4, p < 0.05, n = 3) and collagenase activity (289 +/- 5.8% vs 100 +/- 10.9%, p < 0.05, n = 9) in conditioned medium. This last effect was probably not due to a reduction in TIMP-1 (tissue inhibitor of metalloproteinase-1) because levels of mRNA for this inhibitor were not lower in treated cells. The efficacy of liposome-associated IFN-alpha-2b in vitro supports the concept of the topical use of this anti-fibrogenic agent for treatment of fibroproliferative disorders.

Cell Division↗

PubMed1997

[The development of a special instrument for measuring propagation velocity distribution of compound active potential using collision method].

This paper introduced a special instrument for measuring the propagation velocity distribution of compound active potential using collision method. In briefly, the principle of collision method is introduced. The structure and operation principle of the neuroelectrical amplifier, A/D converter and computer interface circuit are emphatically discussed. The instrument has the advantage of usable and low costing. It has considerable application value in clinical pathological diagnosis and research experiments of nervous system.

Action Potentials↗