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1.
Chinese Journal of Dermatology ; (12): 710-714, 2017.
Article in Chinese | WPRIM | ID: wpr-660530

ABSTRACT

Objective To investigate the photoregulation of transient receptor potential ankyrin 1 (TRPA1) in HaCaT cells,and to explore its mechanisms.Methods Cultured HaCaT cells were divided into 225-mJ/cm2 UVA radiation groups and 25-mJ/cm2 UVB radiation groups.HaCaT cells in the UVA radiation groups were further classified into 6 groups:blank control group 1 receiving no treatment,retinal group 1 treated with 12 μmol/L retinal alone,UVA group treated with 225 mJ/cm2 UVA radiation alone,retinal + UVA group (UVA-TRPA1 control group),retinal + UVA + 500 μmol/L cinnamaldehyde group (UVA-TRPA1 agonist group) and retinal + UVA + 1 mmol/L camphor group (UVA-TRPA1 antagonist group).Additionally,HaCaT cells in the UVB radiation groups were also further classified into 6 groups:blank control group 2 receiving no treatment,retinal group 2 treated with 12 μmol/L retinal alone,UVB group treated with 25-mJ/cm2 UVB radiation,retinal + UVB group (UVB-TRPA1 control group),retinal + UVB + 500 μmol/L cinnamaldehyde group (UVB-TRPA1 agonist group) and retinal + UVB + 1 mmol/L camphor group (UVB-TRPA1 antagonist group).Real-time fluorescence-based quantitative PCR (qPCR) and Western blot analysis were performed to determine the mRNA and protein expression of TRPA 1 respectively.Flow cytometry was conducted to investigate changes of calcium influx in HaCaT cells in the above groups.Results qPCR and Western blot analysis showed that TRPA1 mRNA and protein were expressed in HaCaT cells.The fluorescence intensity of calcium influx significantly differed among the blank control group 1,retinal group 1,UVA group and retinal + UVA group (155.06 ± 7.62,148.37 ± 18.77,166.92 ± 3.71 and 331.333 ± 40.563;F =44.509,P < 0.01),as well as among the blank control group 2,retinal group 2,UVB group and retinal + UVB group (150.20 ± 1.73,171.66 ± 56.23,147.56 ± 6.60 and 250.44 ± 9.13;F =85.261,P < 0.01).Additionally,retinal + UVA/UVB groups showed significantly higher fluorescence intensity of calcium influx compared with the blank control groups (q =18.442,6.052,P < 0.01).The TRPA1 agonist cinnamaldehyde and its antagonist camphor could regulate the UVA-and UVB-induced calcium influx (P < 0.001).Compared with the blank control group 1 and 2 respectively,the fluorescence intensity of retinal-dependent calcium influx was significantly higher in the UVA/UVB-TRPA1 agonist group (q =14.934,32.770,P < 0.001),and significantly lower in the UVA/UVB-TRPA1 antagonist group (q =7.986,14.596,P < 0.001).Conclusion TRPA1 is expressed in HaCaT cells,and UVA or UVB can regulate the calcium influx in HaCaT cells by adjusting the activity of TRPA 1.

2.
Chinese Journal of Dermatology ; (12): 710-714, 2017.
Article in Chinese | WPRIM | ID: wpr-657949

ABSTRACT

Objective To investigate the photoregulation of transient receptor potential ankyrin 1 (TRPA1) in HaCaT cells,and to explore its mechanisms.Methods Cultured HaCaT cells were divided into 225-mJ/cm2 UVA radiation groups and 25-mJ/cm2 UVB radiation groups.HaCaT cells in the UVA radiation groups were further classified into 6 groups:blank control group 1 receiving no treatment,retinal group 1 treated with 12 μmol/L retinal alone,UVA group treated with 225 mJ/cm2 UVA radiation alone,retinal + UVA group (UVA-TRPA1 control group),retinal + UVA + 500 μmol/L cinnamaldehyde group (UVA-TRPA1 agonist group) and retinal + UVA + 1 mmol/L camphor group (UVA-TRPA1 antagonist group).Additionally,HaCaT cells in the UVB radiation groups were also further classified into 6 groups:blank control group 2 receiving no treatment,retinal group 2 treated with 12 μmol/L retinal alone,UVB group treated with 25-mJ/cm2 UVB radiation,retinal + UVB group (UVB-TRPA1 control group),retinal + UVB + 500 μmol/L cinnamaldehyde group (UVB-TRPA1 agonist group) and retinal + UVB + 1 mmol/L camphor group (UVB-TRPA1 antagonist group).Real-time fluorescence-based quantitative PCR (qPCR) and Western blot analysis were performed to determine the mRNA and protein expression of TRPA 1 respectively.Flow cytometry was conducted to investigate changes of calcium influx in HaCaT cells in the above groups.Results qPCR and Western blot analysis showed that TRPA1 mRNA and protein were expressed in HaCaT cells.The fluorescence intensity of calcium influx significantly differed among the blank control group 1,retinal group 1,UVA group and retinal + UVA group (155.06 ± 7.62,148.37 ± 18.77,166.92 ± 3.71 and 331.333 ± 40.563;F =44.509,P < 0.01),as well as among the blank control group 2,retinal group 2,UVB group and retinal + UVB group (150.20 ± 1.73,171.66 ± 56.23,147.56 ± 6.60 and 250.44 ± 9.13;F =85.261,P < 0.01).Additionally,retinal + UVA/UVB groups showed significantly higher fluorescence intensity of calcium influx compared with the blank control groups (q =18.442,6.052,P < 0.01).The TRPA1 agonist cinnamaldehyde and its antagonist camphor could regulate the UVA-and UVB-induced calcium influx (P < 0.001).Compared with the blank control group 1 and 2 respectively,the fluorescence intensity of retinal-dependent calcium influx was significantly higher in the UVA/UVB-TRPA1 agonist group (q =14.934,32.770,P < 0.001),and significantly lower in the UVA/UVB-TRPA1 antagonist group (q =7.986,14.596,P < 0.001).Conclusion TRPA1 is expressed in HaCaT cells,and UVA or UVB can regulate the calcium influx in HaCaT cells by adjusting the activity of TRPA 1.

3.
Chinese Journal of Comparative Medicine ; (6): 67-70, 2015.
Article in Chinese | WPRIM | ID: wpr-463178

ABSTRACT

Objective To assess the health status of rodent laboratory animals by pathological diagnosis, our lab has being take apart in investigating the quality of laboratory animals in Beijing area for years and offer some advices for standardized breeding to ensure accurate results of scientific research.This paper focuses on the analysis of laboratory rodent samples that collected in October 2014.Methods We collected the heart, liver, spleen, lung, kidney, large intestine and small intestine, and put these organs into 10%Calcium formaldehyde solution for fixation, and then prepared into two different sections for optical microscopy observation including all paraffin specimens stained with H&E and the frozen sections stained with Oil Red-O and PAS.Results The vast majority of laboratory rodents were up to standard, but there still a problem in individual units.The main problem is liver and lung disease.The rate of Hepatocyte swellingis 6%(mouse), 2.5% (rat), 8.2% (guinea pig), moreover part of them were lipidosis, according to Oil Red-O stain.the mainly problem of lung is congestion ,edema and Interstitial pneumonia ,the detectable rate of pulmonarydiseases is 15.5%(guinea pig).Conclusions The vast majority of laboratory rodents were pathologically diagnosed as healthy animals.The liver disease may be caused by improper feeding.And disease of lung may led by haze, unqualified bedding and low temperature.

4.
Chinese Journal of Dermatology ; (12): 382-386, 2015.
Article in Chinese | WPRIM | ID: wpr-468759

ABSTRACT

Objective To explore molecular mechanisms underlying the in vitro counteracting effect of curcumin on malignant melanoma.Methods Cultured A375 and C8161 human melanoma cells were cultivated in vitro,and randomly divided into several test groups and a control group to be treated with different concentrations of curcumin and dimethyl sulfoxide respectively for different durations.Then,methyl thiazolyl tetrazolium (MTT) assay,Transwell assay,flow cytometry and Western blot were performed to evaluate the effect of curcumin on the proliferation,invasion and cell cycle of,as well as expressions of AKT/mTOR signaling pathway-related proteins in A375 and C8161 cells respectively.Statistical analysis was carried out by using t test.Results MTT assay showed that the treatment with curcumin of 5-35 mg/L for 24-96 hours significantly inhibited the proliferation of both A375 and C8161 cells compared with that with dimethyl sulfoxide (all P < 0.001),and the inhibitory effect was in a dose-dependent manner within the range of 5-15 mg/L for A375 cells and within the range of 5-10 mg/L for C8161 cells,and in a time-dependent manner from 0 to 48 hours for both cells.After treatment for 24 hours,the 50% inhibitory concentration (IC50) of curcumin against A375 cells and C 8161 cells was 10 mg/L and 5 mg/L respectively.Transwell assay demonstrated that the invasion of A375 and C8161 cells was significantly suppressed by 72-hour treatment with curcumin at 10 mg/L and 5 mg/L respectively (both P < 0.001).Flow cytometry showed that the cell cycle of A375 and C8161 cells was arrested at G2/M phase after 24-hour treatment with curcumin at 10 mg/L and 5 mg/L respectively,with significant differences in the proportion of A375 cells and C8161 cells in G2/M phase between the test group and control group (A375 cells:35.00% ± 3.54% vs.120.80% ± 7.46%,P< 0.001;C8161 cells:19.33% ± 4.04% vs.85.00% ± 9.53%,P < 0.001).Western blot revealed that the expressions of AKT/mTOR signaling pathway-related proteins were decreased in A375 and C8161 cells after 24-hour treatment with 10 mg/L and 5 mg/L curcumin respectively.Conclusion Curcumin can inhibit the proliferation and invasion of A375 and C8161 cells,likely by blocking cell cycle and inhibiting activation of the AKT/mTOR signaling pathway.

5.
Chinese Journal of Dermatology ; (12): 248-251, 2015.
Article in Chinese | WPRIM | ID: wpr-468688

ABSTRACT

Morphea complicated by Hashimoto's thyroiditis is reported in two sisters.Case 1:a 64-year-old female presented with skin rashes on the anterior neck,trunk and bilateral anterior shins for 5 years,itching skin rashes on the perineum for 4 years,and Hashimoto's thyroiditis for 9 years.Physical examination revealed grade 1 enlargement of firm thyroid gland without exophthalmos or pretibial myxedema.Dermatological examination showed pink patches on the neck and breast,sclerosis and atrophy of skin over the back,porcelain-white patches on the perineum.Histopathological findings suggested the diagnosis of morphea on the breast and lichen sclerosus et atrophicus on the perineum.Case 2:a 55-year-old female,who was the younger sister of case 1,suffered from gradual sclerosis and atrophy of skin in the left inframammary region and abdominal region for 4 years,as well as Hashimoto's thyroiditis for 3 years.Similarly,physical examination revealed grade 1 enlargement of firm thyroid gland without exophthalmos or pretibial myxedema.Hypopigmentation,sclerosis and atrophy of skin were observed in the left inframammary region,abdominal region and central back region.Histopathological examination suggested a diagnosis of morphea.According to the clinical and histopathological manifestations,periodic acid-Schiff staining and thyroid gland function test results,the 2 cases were both diagnosed as morphea complicated by Hashimoto's thyroiditis.

6.
Chinese Journal of Comparative Medicine ; (6): 24-26, 2014.
Article in Chinese | WPRIM | ID: wpr-457453

ABSTRACT

Objective Mongolian gerbil can make themself urine concentration for saving water and adapt to the harsh desert environment, due to their very unique moisture control system in the body.Methods Mongolian gerbil is resistant to drought on account of their special kidney. Histology of the kidney, ureter and bladder in Meriones Unguiculataus were observed by light microscopy using HE staining.Results The results showed that compared with rats and mice, the Mongolian gerbils have more developed distal tubules, and well developed inner renal medulla.Conclusions We hope that the findings of this study enrich our understanding of the histology of urinary system in Mongolian gerbils and provide support for the laboratory animalization of this animal.

7.
Chinese Journal of Dermatology ; (12): 871-876, 2013.
Article in Chinese | WPRIM | ID: wpr-439601

ABSTRACT

Objective To investigate the regulatory effect of glutamate signaling pathway on filopodia formation in epidermal cells and on melanosome transfer.Methods Epidermal melanocytes and keratinocytes were isolated from human foreskin and subjected to subculture.After two to three passages of subculture,the melanocytes and keratinocytes were cultured alone or in combination with or without the presence of MK801 (an antagonist of N-methyl-D-aspartic acid (NMDA) receptor) of 100 μmol/L,or NMDA (the activator of NMDA receptor) of 100 μmol/L,for 24 hours.The melanocytes irradiated with UVB at 311 nm served as the control.Scanning electron microscopy was used to observe the appearance of filopodia and dendrites of melanocytes and keratinocytes.Melanosome transfer was visualized under confocal laser scanning microscopy after double immunofluorescent staining.Results Although no obvious changes were observed in the number of dendrites in monocultured melanocytes after treatment with MK801 or NMDA for 24 hours,dendrites became thinner at the terminus and longer with a decrease in the number and length of filopodia after MK801 treatment,but thicker and shorter with an increase in the number and length of filopodia after NMDA treatment compared with untreated monocultured melanocytes.In the coculture system,filopodia were observed between the untreated melanocytes and keratinocytes,and the number of filopodia in melanocytes was larger in the side adjacent to keratinocytes than in the opposite side.Compared with the untreated coculture system,the number of both filopodia connecting melanocytes and keratinocytes and filopodia extending from melanocytes to keratinocytes decreased in the coculture system after treatment with MK801 of 100 μmol/L,but increased after treatment with NMDA of 100 μmol/L,for 24 hours.Melanosomes were found in keratinocytes cocultured with melanocytes without treatment,which were decreased in number after 24-hour treatment with MK801 of 100 μmol/L,but increased in number and even present in keratinocytes nonadiacent to melanocytes after 24-hour treatment with NMDA of 100 μmol/L.Conclusion Glutamate signaling pathway may modulate the transfer of melanosomes from melanocytes to keratinocytes via modulating the appearance of melanocyte dendrites and formation of filopodia.

8.
Chinese Journal of Dermatology ; (12): 616-619, 2012.
Article in Chinese | WPRIM | ID: wpr-424087

ABSTRACT

Objective To investigate the roles of glutamate signaling pathway in the activation of human peripheral blood lymphocytes(PBLs) and pathogenesis of vitiligo.Methods Peripheral blood lymphocytes (PBLs) isolated from 5 patients with generalized vitiligo and 5 healthy controls were cultured in vitro.Flow cytometry was performed to quantify the expression of CD25 and interferon-γ on PBLs derived from healthy controls and treated with MK801 (a non-competitive antagonist of N-methyl-D-aspartic acid receptor,NMDAR) at 100 μmol/L or phosphate buffered saline (PBS) for 48 hours,as well as the level of reactive oxygen species (ROS) in the controlderived PBLs treated with MK801 at 100 μmol/L,NMDA (an agonist of N-methyl-D-aspartic acid receptor) at 0.5 mmol/L or PBS for 48 hours.The protein and mRNA expressions of NMDAR1 and NMDAR2A were measured by flow cytometry and real-time PCR,respectively,in PBLs from the healthy controls and vitiligo patients.Immunohistochemistry was used to observe the expressions of NMDAR1 and NMDAR2A in tissue specimens from depigmented and postinflammatory hyperpigmentation lesions of the patients with vitiligo and from normal skin of the healthy controls.Results Compared with the PBS-treated PBLs from the healthy controls,the MK801-treated PBLs showed a downregulated expression of CD25 (7.28% ± 0.18% vs.16.02% ± 0.42%,P < 0.01),but an upregulated proportion of CD25+IFN-γ+ lymphocytes (1.79% ± 0.09% vs.0.78% ± 0.06%,P < 0.01),and the NMDA-treated PBLs displayed a higher ROS level (101.1 ± 3.50 vs.69.80 ± 2.08,P< 0.01 ).The protein expression of NMDAR1 in PBLs was significantly higher in vitiligo patients than in the healthy controls (3.85 ± 2.17 vs.0.97 ±0.55,P < 0.05).Conclusion Glutamate signaling pathway may be involved in the immunopathogenesis of vitiligo via affecting the secretion of interferon-γ by,and ROS level in,activated lymphocytes.

9.
Chinese Journal of Dermatology ; (12): 700-703, 2012.
Article in Chinese | WPRIM | ID: wpr-420896

ABSTRACT

Objective To investigate the roles of glutamate signaling pathway in melanin transfer.MethodsEpidermal melanocytes and keratinocytes were isolated from human foreskin tissue followed by purification and primary culture.Immunofluorescence microscopy was conducted to observe the intracellular distribution of N-methy-D-aspartate receptor 1 (NMDAR1) and NMDAR2A in melanocytes.Some melanocytes were classified into 4 groups to be pretreated with MK801 (the NMDAR antagonist dizocilpine maleate) at 100μmol/L for 5 minutes followed by treatment with NMDA(an NMDAR agonist) at 100 μmol/L (MK801-pretreated group 1),pretreated with MK801 at 100 μmol/L for 1 hour followed by treatment with NMDA at 100μmol/L (MK801-pretreated group 2),treated with MK801 at 100 μmol/L for 5 minutes (MK801 group),treated with NMDA at 100 μmol/L for 5 minutes (NMDA group),respectively,then,confocal microscopy was performed to measure the intracellular calcium (Ca2+) concentration of the melanocytes.The distribution of β-tubulin was visualized by confocal microscopy in melanocytes treated with MK801 at 100 μmol/L for 24 hours.Some melanocytes and keratinocytes were cocultured with or without MK801 at 100 μmol/L for 24 or 48 hours,then,scaning microscopy was carried out to observe the junction structure between melanocytes and keratinocytes,and alkali method coupled with spectrophotometric analysis to determine melanin content in keratinocytes.Results The intracellular calcium concentration of melanocytes was decreased by MK-801,but increased by NMDA at 100 μmol/L,and the increase was blocked by the pretreatment with MK-801 for 5 minutes or 1 hour.After incubation with MK-801 at 100 μmol/L for 24 hours,a more intense staining for β-tubulin was observed around the nuclei of melanocytes.There was a significant reduction in the number of filopodia on the surface of and between melanocytes and keratinocytes after treatment with MK-801 at 100 μmol/L for 48 hours.Also,the content of melanin(represented as the absorbance value at 375 nm) transferred from melanocytes into keratinocytes was statistically reduced in coculture system treated with MK-801 at 100 μmol/L compared with that without treatment (0.158 ± 0.003 vs.2.203 ± 0.006,t =6.323,P < 0.01 ).Conclusions The glutamate signaling pathway exerts a regulatory effect on intracellular calcium concentration of distribution of β-tubulin in,filopodia formation of melanocytes and melanin transfer between melanocytes and keratinocytes.

10.
Chinese Journal of Dermatology ; (12): 186-190, 2011.
Article in Chinese | WPRIM | ID: wpr-413663

ABSTRACT

Objective To investigate the action mechanism of glutamate-mediated signaling pathway in malignant melanoma. Methods WM451LU melanoma cells in log phase were classified into 6 groups, negative control group treated with PBS (100 μl), MK801 group treated with the non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist MK-801 (100 μmol/L), CPCCOEt group treated with non-competitive metabotropic glutamate receptor 1 (mGluR1) antagonist CPCCOEt, MAP2 group transfected with adenovirus vector containing microtubule associated protein 2a (Ad-MAP2a), MK801 + MAP2 group treated with MK801 of 100 μmol/L and transfected with Ad-MAP2a, CPCCOEt + MAP2 group treated with CPCCOEt of 10 μmol/L and transfected with Ad-MAP2a. Western blot was performed to detect the expression of an ionotropic glutamate receptor, i.e., N-methyl-D-aspartate receptor type 2A (NMDAR2A) in WM451LU cells transfected with Ad-MAP2a. Scratch motility assay and cell invasion assay were conducted in vitro to detect the changes in migration and invasion ability of WM451LU cells after treated with Ad-MAP2a, MK-801, CPCCOEt alone or in combination. In vivo study was carried out to compare the inhibitory effect of the above treatments on melanoma. Results Western blot revealed a decrease in the expression of NMDAR2A in WM451LU cells after transfected with Ad-MAP2a. The scratch motility assay showed that the number of migrating cells per high power field was 117.04 ± 2.76 in MAP2 group,107.64 ± 6.50 in MK801 group,97.36 ± 4.79 in CPCCOEt group, 43.28 ± 3.02 in MK801 + MAP2 group,30.76 ± 3.97 in CPCCOEt + MAP2 group,significantly different from that in the negative control group (152.3 ± 5.75,all P < 0.01 ). Cell invasion assay demonstrated that the average number of invading cells per high power field in the negative control was significantly higher than that in MAP2 group, MK801 group, CPCCOEt group, MK801+MAP2 group and CPCCOEt + MAP2 group (170.43 ±8.72 vs. 98.26 ± 3.84, 97.22 ± 5.54, 112.23 ± 7.21, 42.89 ± 5.06, 58.25 ± 6.68, P < 0.05, 0.05, 0.05, 0.01and 0.01, respectively).A significant decrease was observed in the average volume of experimental melanoma in mice of MAP2 group, MK801 group, MK801 + MAP2 group, CPCCOEt group and CPCCOEt + MAP2 group compared with the negative control group (224.02 ± 46.19 mm3, 160.33 ± 33.91 mm3, 91.49 ± 21.48 mm3,202.30 ± 52.37 mm3, 111.13 ± 69.81 mm3 vs. 342.70 ± 60.92 mm3, all P < 0.01 ). Conclusions To block the glutamate signaling pathway in vitro can inhibit the invasion and migration of melanoma cells, and to block the pathway in vivo can inhibit the growth of malignant melanoma and alter the morphology of melanoma cells.

11.
Chinese Journal of Dermatology ; (12): 575-578, 2009.
Article in Chinese | WPRIM | ID: wpr-391343

ABSTRACT

Objective To investigate the effects of glutamate receptor signaling on melanoma cell dendrite morphology and cytoskeleton protein. Methods A metastatic human malignant melanoma cell line WM451LU was cultured and transfected by recombinant adenovirus vector carrying a cDNA encoding microtubule-associated protein 2a (MAP2a). MK-801, an antagonist of N-methyl-D-aspartate receptor (NMDAR), and CPCCOEt, an antagonist of metabotropie glutamate receptor 1 (mGluR1), were used to treat transfected or untrausfeeted WM451LU cells. Confocal microscopy and three dimensional atomic force microscopy were used to assess subcellular location of NMDAR2A, mGluR1 and MAP2a as well as the dis-tribution of α-tubulin in and dendrite morphology of WM451LU cells. The proliferation of WM451LU cells was estimated by cell survival growth curve. Results Confocal laser microscopy revealed that NMDAR2A, mGluRl and MAP2a were mainly co-localized in melanoma cell dendrites. Both MK-801 and CPCCOEt increased the density of microtubules in cell dendrites and dendritic branching of WM451LU cells, and both effects of MK-801 and CPCCOEt were enhanced by the expression of MAP2a. Furthermore, the proliferation of WM451LU cells was significantly inhibited by MK-801 of 100 μmol/L and CPCCOEt of 10 μmol/L. Conclusions In melanoma cells, glutamate receptors may participate in the development of dendrites, and anta- gonists of glutamate receptors could inhibit the proliferation of melanoma cells.

12.
Chinese Journal of Dermatology ; (12)1994.
Article in Chinese | WPRIM | ID: wpr-517615

ABSTRACT

Objective T o observe the therapeutic effect of Radix Astragali Injectio on psoriasis and it s possible pharmaceutical mechanism. Methods Two groups of patients with psoriasis vulgaris were treated with either comprehensive regi men or comprehensive regimen plus Radix Astragali Injectio. The clinical respons es in both groups were compared. Meanwhile, the effects of Radix Astragali Decoc tion and Injectio on proliferation of vaginal epithelium, PCNA expression, diffe rentiation of tail scale epidermis and plasma ET-1 were assessed in mouse mode l. Results It was shown that psoriatic lesions began to fade significantly earli er in Radix Astragali group than in routine comprehensive treatment group. The c linical cure rate was significantly higher in Radix Astragali group also. Animal experiment indicated that Radix Astragali Injectio had effects on all 4 indices mentioned above and the effects of the Injectio was stronger than that of the D ecoction. Conclusions Radix Astragali Injectio is effective for psoriasis vulgar is. Its therapeutic effects may be explained by blocking multiple pathogenetic l inkage.

13.
Chinese Medical Equipment Journal ; (6)1989.
Article in Chinese | WPRIM | ID: wpr-583665

ABSTRACT

In order to check out the cortical EEG signals of conscious and/or anesthetized rats, a 16-channel analog signals preprocessor is developed. This preprocessor can amplify and filter the primal EEG signals to transform them into ones with proper altitudes and high SNRs, and then they will be sent to the A.D converter. Some measures are taken in view of the signals' low frequencies, low SNRs and background with strong interference. When high gain made, such performances of the circuit are emphasized as low noise, low offset voltage, low gain error and heightened CMRR.

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