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BACKGROUND/AIMS: The rejuvenation properties of nanofat grafting have been described in recent years. However, it is not clear whether the clinical efficacy of the procedure is attributable to stem cells or linked to other components of adipose tissue. In this study we isolated nanofat-derived stem cells (NFSCs) to observe their biological characteristics and evaluate the efficacy of precise intradermal injection of nanofat combined with platelet-rich fibrin (PRF) in patients undergoing facial rejuvenation treatment. METHODS: Third-passage NFSCs were isolated and cultured using a mechanical emulsification method and their surface CD markers were analyzed by flow cytometry. The adipogenic and osteogenic nature and chondrogenic differentiation capacity of NFSCs were determined using Oil Red O staining, alizarin red staining, and Alcian blue staining, respectively. Paracrine function of NFSCs was evaluated by enzyme-linked immunosorbent assay (ELISA) at 1, 3, 7, 14, and 28 days after establishing the culture. Then, the effects of PRF on NFSC proliferation were assessed in vitro. Finally, we compared the outcome in 103 patients with facial skin aging who underwent both nanofat and intradermal PRF injection (treatment group) and 128 patients who underwent hyaluronic acid (HA) injection treatment (control group). Outcomes in the two groups were compared by assessing pictures taken at the same angle before and after treatment, postoperative recovery, incidence of local absorption and cysts, and skin quality before treatment, and at 1, 12, 24 months after treatment using the VISIA Skin Image Analyzer and a SOFT5.5 skin test instrument. RESULTS: NFSCs expressed CD29, CD44, CD49d, CD73, CD90, and CD105, but did not express CD34, CD45, and CD106. NFSCs also differentiated into adipocytes, osteoblasts, and chondrocytes under appropriate induction conditions. NFSCs released large amounts of growth factors such as VEGF, bFGF, EGF, and others, and growth factor levels increased in a time-dependent manner. At the same time, PRF enhanced proliferation of NFSCs in vitro in a dose-dependent manner, and the growth curves under different concentrations of PRF all showed plateaus 6d after seeding. Facial skin texture was improved to a greater extent after combined injection of nanofat and PRF than after control injection of HA. The nanofat-PRF group had a higher satisfaction rate. Neither treatment caused any complications such as infection, anaphylaxis, or paresthesia during long-term follow-up. CONCLUSION: NFSCs demonstrate excellent multipotential differentiation and paracrine function, and PRF promotes proliferation of NFSCs during the early stage after seeding. Both nanofat-PRF and HA injection improve facial skin status without serious complications, but the former was associated with greater patient satisfaction, implying that nanofat-PRF injection is a safe, highly effective, and long-lasting method for skin rejuvenation.
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Tecido Adiposo/citologia , Fibrina Rica em Plaquetas/metabolismo , Rejuvenescimento , Envelhecimento da Pele , Fenômenos Fisiológicos da Pele , Células Estromais/citologia , Células Estromais/transplante , Adulto , Proliferação de Células , Células Cultivadas , Face , Feminino , Humanos , Injeções Intradérmicas , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Masculino , Pessoa de Meia-Idade , Células Estromais/metabolismo , Adulto JovemRESUMO
Acute pancreatitis (AP) is one of the most common acute abdominal conditions, and its incidence has been increasing for years. Approximately 15-20% of patients develop severe AP (SAP), which is complicated by critical inflammatory injury and intestinal dysfunction. AP-associated inflammation can lead to the gut barrier and function damage, causing dysbacteriosis and facilitating intestinal microbiota migration. Pancreatic exocrine deficiency and decreased levels of antimicrobial peptides in AP can also lead to abnormal growth of intestinal bacteria. Meanwhile, intestinal microbiota migration influences the pancreatic microenvironment and affects the severity of AP, which, in turn, exacerbates the systemic inflammatory response. Thus, the interaction between the gut microbiota (GM) and the inflammatory response may be a key pathogenic feature of SAP. Treating either of these factors or breaking their interaction may offer some benefits for SAP treatment. In this review, we discuss the mechanisms of interaction of the GM and inflammation in AP and factors that can deteriorate or even cure both, including some traditional Chinese medicine treatments, to provide new methods for studying AP pathogenesis and developing therapies.
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Purpose: Papillary thyroid cancer (PTC) has grown rapidly in prevalence over the past few decades, and central neck lymph node metastasis (CNLNM) is associated with poor prognoses. However, whether to carry out preventive central neck lymph node dissection (CNLND) is still controversial. We aimed to construct a prediction model of CNLNM to facilitate making clinical surgical regimens. Methods: A total of 691 patients with PTC between November 2018 and December 2021 were included in our study. Univariate and multivariate analyses were performed on basic information and clinicopathological characteristics, as well as ultrasound characteristics (American College of Radiology (ACR) scores). The prediction model was constructed and performed using a nomogram, and then discriminability, calibrations, and clinical applicability were evaluated. Results: Five variables, namely, male, age >55 years, clinical lymph node positivity, tumor size ≥1 cm, and ACR scores ≥6, were independent predictors of CNLNM in the multivariate analysis, which were eventually included to construct a nomogram model. The area under the curve (AUC) of the model was 0.717, demonstrating great discriminability. A calibration curve was developed to validate the calibration of the present model by bootstrap resampling, which indicated that the predicted and actual values were in good agreement and had no differentiation from the ideal model. The decision curve analysis (DCA) indicated that the prediction model has good clinical applicability. Conclusions: Our non-invasive prediction model combines ACR scores with clinicopathological features presented through nomogram and has shown good performance and application prospects for the prediction of CNLNM in PTCs.
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Nomogramas , Neoplasias da Glândula Tireoide , Humanos , Masculino , Pessoa de Meia-Idade , Câncer Papilífero da Tireoide/diagnóstico por imagem , Câncer Papilífero da Tireoide/cirurgia , Metástase Linfática , Linfonodos/diagnóstico por imagem , Linfonodos/cirurgia , Neoplasias da Glândula Tireoide/diagnóstico por imagem , Neoplasias da Glândula Tireoide/cirurgiaRESUMO
Severe burns are acute wounds caused by local heat exposure, resulting in life-threatening systemic effects and poor survival. However, the specific molecular mechanisms remain unclear. First, we downloaded gene expression data related to severe burns from the GEO database (GSE19743, GSE37069, and GSE77791). Then, a gene expression analysis was performed to identify differentially expressed genes (DEGs) and construct protein-protein interaction (PPI) network. The molecular mechanism was identified by enrichment analysis and Gene Set Enrichment Analysis. In addition, STEM software was used to screen for genes persistently expressed during response to severe burns, and receiver operating characteristic (ROC) curve was used to identify key DEGs. A total of 2631 upregulated and 3451 downregulated DEGs were identified. PPI network analysis clustered these DEGs into 13 modules. Importantly, module genes mostly related with immune responses and metabolism. In addition, we identified genes persistently altered during the response to severe burns corresponding to survival and death status. Among the genes with high area under the ROC curve in the PPI network gene, CCL5 and LCK were identified as key DEGs, which may affect the prognosis of burn patients. Gene set variation analysis showed that the immune response was inhibited and several types of immune cells were decreased, while the metabolic response was enhanced. The results showed that persistent gene expression changes occur in response to severe burns, which may underlie chronic alterations in physiological pathways. Identifying the key altered genes may reveal potential therapeutic targets for mitigating the effects of severe burns.
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Queimaduras , Bases de Dados de Ácidos Nucleicos , Perfilação da Expressão Gênica , Redes Reguladoras de Genes/imunologia , Mapas de Interação de Proteínas/imunologia , Transcriptoma/imunologia , Queimaduras/genética , Queimaduras/imunologia , Queimaduras/patologia , Biologia Computacional , Humanos , Índices de Gravidade do TraumaRESUMO
[This corrects the article DOI: 10.1155/2021/8836243.].
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In this research and development project, we used the general microprocessor as a core to constitute the animal cardiac pacemaker in vitro. Control of the pacemaker's settings was carried out by transmitting parameters through a serial communication interface. Finally, our pacemaker reaches a satisfying test result in activating the cardiac outer membrane of the rabbits. Full digital pacemaker has high precision, good stability, and has an intuitive way to set parameters. Owing to its smaller size, lower cost, and easier mass production, the digital pacemaker is a good candidate to replace costly medical pacemakers for activating the animal's heart.
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Eletrocardiografia/métodos , Desenho de Equipamento , Marca-Passo Artificial/veterinária , Processamento de Sinais Assistido por Computador , Animais , Masculino , Microcomputadores , Coelhos , PesquisaRESUMO
Severe acute pancreatitis (SAP) is a critical abdominal disease associated with high death rates. A systemic inflammatory response promotes disease progression, resulting in multiple organ dysfunction. The functions of neutrophils in the pathology of SAP have been presumed traditionally to be activation of chemokine and cytokine cascades accompanying the inflammatory process. Recently, since their discovery, a new type of antimicrobial mechanism, neutrophil extracellular traps (NETs), and their role in SAP, has attracted widespread attention from the scientific community. Significantly different from phagocytosis and degranulation, NETs kill extracellular microorganisms by releasing DNA fibers decorated with granular proteins. In addition to their strong antimicrobial functions, NETs participate in the pathophysiological process of many noninfectious diseases. In SAP, NETs injure normal tissues under inflammatory stress, which is associated with the activation of inflammatory cells, to cause an inflammatory cascade, and SAP products also trigger NET formation. Thus, due to the interaction between NET generation and SAP, a treatment targeting NETs might become a key point in SAP therapy. In this review, we summarize the mechanism of NETs in protecting the host from pathogen invasion, the stimulus that triggers NET formation, organ injury associated with SAP involving NETs, methods to interrupt the harmful effects of NETs, and different therapeutic strategies to preserve the organ function of patients with SAP by targeting NETs.
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OBJECTIVE: To explored the effect of stromal cell-derived factor 1α (SDF-1α) on promoting the migration ability of rat adipose derived stem cells (rADSCs) by constructed the rADSCs overexpression SDF-1α via adenovirus transfection. METHODS: rADSCs were isolated from adipose tissue of 6-week-old SPF Sprague Dawley rats. Morphological observation, multi-directional differentiations (osteogenic, adipogenic, and chondrogenic inductions), and flow cytometry identification were performed. Transwell cell migration experiment was used to observe and screen the optimal concentration of exogenous SDF-1α to optimize the migration ability of rADSCs; the optimal multiplicity of infection (MOI) of rADSCs was screened by observing the cell status and fluorescence expression after transfection. Then the third generation of rADSCs were divided into 4 groups: group A was pure rADSCs; group B was rADSCs co-cultured with SDF-1α at the best concentration; group C was rADSCs infected with recombinant adenovirus-mediated green fluorescent protein (Adv-GFP) with the best MOI; group D was rADSCs infected with Adv-GFP-SDF-1α overexpression adenovirus with the best MOI. Cell counting kit 8 (CCK-8) and Transwell cell migration experiment were preformed to detect and compare the effect of exogenous SDF-1α and SDF-1α overexpression on the proliferation and migration ability of rADSCs. RESULTS: The cell morphology, multi-directional differentiations, and flow cytometry identification showed that the cultured cells were rADSCs. After screening, the optimal stimulating concentration of exogenous SDF-1α was 12.5 nmol/L; the optimal MOI of Adv-GFP adenovirus was 200; the optimal MOI of Adv-GFP-SDF-1α overexpression adenovirus was 400. CCK-8 method and Transwell cell migration experiment showed that compared with groups A and C, groups B and D could significantly improve the proliferation and migration of rADSCs ( P<0.05); the effect of group D on enhancing the migration of rADSCs was weaker than that of group B, but the effect of promoting the proliferation of rADSCs was stronger than that of group D ( P<0.05). CONCLUSION: SDF-1α overexpression modification on rADSCs can significantly promote the proliferation and migration ability, which may be a potential method to optimize the application of ADSCs in tissue regeneration and wound repair.
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Adipócitos , Quimiocina CXCL12 , Animais , Ratos , Ratos Sprague-Dawley , Células-Tronco , Células EstromaisRESUMO
BACKGROUND: The complications acute lung injury and acute kidney injury caused by severe inflammation are the main reasons of high mortality of severe acute pancreatitis (SAP). These two complications can both lead to water metabolism and acid-base balance disorders, which could act as additional critical factors affecting the disease trend. Aquaporins (AQPs), which can regulate the transmembrane water transport, have been proved to participate in the pathophysiological process of SAP and the associated complications, such as acute lung injury and acute kidney injury. Thus, exploring herbs that can effectively regulate the expression of AQP in SAP could benefit the prognosis of this disease. AIM: To determine whether Yue-Bi-Tang (YBT) can regulate the water metabolism in rats with severe acute pancreatitis via regulating the expression of aquaporins. METHODS: Sprague-Dawley rats were randomly divided into three groups, sham operation group (SOG), model group (MG), and treatment group (TG). SAP was induced with 3.5% sodium taurocholate in the MG and TG. Rats in the TG were administered with YBT while SOG and MG rats were given the same volume of saline. Blood and tissue samples were harvested to detect serum inflammatory cytokines, histopathological changes, malondialdehyde and superoxide dismutase in the lung, and protein and mRNA expression of kidney injury molecule-1, α-smooth muscle actin, and vimentin in the kidney, and AQP1 and 4 in the lung, pancreas, and kidney. RESULTS: The serum interleukin-10, tumor necrosis factor α, and creatinine levels were higher in the MG than in the SOG. Tumor necrosis factor α level in the TG was lower than that in the MG. Malondialdehyde level in lung tissues was higher than in the SOG. The pathological scores and edema scores of the pancreas, lung, and kidney tissues in the MG were all higher than those in the SOG and TG. The protein expression of AQP4 in lung tissues and AQP1 in kidney tissues in the MG were higher than those in the SOG and TG. The expression of vimentin was significantly higher in the MG than in the SOG. The expression of AQP1 mRNA in the lung and kidney, and AQP4 mRNA in the kidney was up-regulated in the MG compared to the SOG. CONCLUSION: YBT might regulate water metabolism to reduce lung and kidney edema of SAP rats via decreasing AQP expression, and alleviate the tissue inflammatory injury.
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Injúria Renal Aguda , Lesão Pulmonar Aguda , Medicamentos de Ervas Chinesas/uso terapêutico , Pancreatite , Doença Aguda , Injúria Renal Aguda/tratamento farmacológico , Lesão Pulmonar Aguda/tratamento farmacológico , Lesão Pulmonar Aguda/etiologia , Animais , Rim , Pulmão , Pancreatite/induzido quimicamente , Pancreatite/tratamento farmacológico , Ratos , Ratos Sprague-Dawley , Fator de Necrose Tumoral alfa , ÁguaRESUMO
BACKGROUND: Acute pancreatitis (AP) is a pancreatic inflammatory disorder that is commonly complicated by extrapancreatic organ dysfunction. Dachengqi decoction (DCQD) has a potential role in protecting the extrapancreatic organs, but the optimal oral administration time remains unclear. AIM: To screen the appropriate oral administration time of DCQD for the protection of extrapancreatic organs based on the pharmacokinetics and pharmacodynamics of AP rats. METHODS: This study consisted of two parts. In the first part, 24 rats were divided into a sham-operated group and three model groups. The four groups were intragastrically administered with DCQD (10 g/kg) at 4 h, 4 h, 12 h, and 24 h postoperatively, respectively. Tail vein blood was taken at nine time points after administration, and then the rats were euthanized and the extrapancreatic organ tissues were immediately collected. Finally, the concentrations of the major DCQD components in all samples were detected. In the second part, 84 rats were divided into a sham-operated group, as well as 4 h, 12 h, and 24 h treatment groups and corresponding control groups (4 h, 12 h, and 24 h control groups). Rats in the treatment groups were intragastrically administered with DCQD (10 g/kg) at 4 h, 12 h, and 24 h postoperatively, respectively, and rats in the control groups were administered with normal saline at the same time points. Then, six rats from each group were euthanized at 4 h and 24 h after administration. Serum amylase and inflammatory mediators, and pathological scores of extrapancreatic organ tissues were evaluated. RESULTS: For part one, the pharmacokinetic parameters (C max, T max, T 1/2, and AUC 0 â t) of the major DCQD components and the tissue distribution of most DCQD components were better when administering DCQD at the later (12 h and 24 h) time points. For part two, delayed administration of DCQD resulted in lower IL-6 and amylase levels and relatively higher IL-10 levels, and pathological injury of extrapancreatic organ tissues was slightly less at 4 h after administration, while the results were similar between the treatment and corresponding control groups at 24 h after administration. CONCLUSION: Delayed administration of DCQD might reduce pancreatic exocrine secretions and ameliorate pathological injury in the extrapancreatic organs of AP rats, demonstrating that the late time is the optimal dosing time.
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Pancreatite , Doença Aguda , Animais , Pancreatite/tratamento farmacológico , Extratos Vegetais , Ratos , Ratos Sprague-DawleyRESUMO
OBJECTIVE: To explore the effect of different-volume fluid resuscitation (FR) on organ functions in severe acute pancreatitis (SAP) and to elucidate the therapeutic effect and mechanism of Poria cocos on organ injuries caused by high-volume FR. METHODS: 1. Clinical study: retrospective analysis of thirty-one patients about the effect of titrated fluid resuscitation protocol (TFR) on the occurrence of acute kidney injury (AKI) secondary to SAP. 2. Experimental study: rats (N = 30) were randomly divided into five groups: sham, model, low-volume FR (1.5 ml/kg/h), high-volume FR (10 ml/kg/h), and Poria cocos combined with high-volume FR (10 ml/kg/h + intraintestinal administration Poria cocos 5 g/kg); serum or plasma indicators and histopathologic scores were compared to explore the effect and mechanism of different fluid volumes and Poria cocos on organ function in SAP. RESULTS: The occurrence of AKI, fluid volume, and fluid velocity in TFR group was lower than that in the control group. Logistic regression analysis showed that increased Marshall scores and fluid velocity were risk factors for predicting occurrence of AKI in SAP. Low-volume FR decreased the levels of blood urea nitrogen (BUN), serum creatinine (Cr), matrix metalloproteinase (MMP), and pathologic scores of the pancreas and kidney. High-volume FR increased ascites, MMPs, and kidney pathologic scores. Poria cocos decreased the levels of BUN, Cr, MMPs, and pathologic scores of the pancreas and kidney and increased the arterial oxygen saturation. CONCLUSION: TFR-associated lower fluid volume and velocity reduced the occurrence of AKI secondary to SAP. High volume might aggravate AKI via increased MMP release leading to endothelial glycocalyx damage and vascular endothelial dysfunction. Poria cocos reduced MMP release, relieved glycocalyx damage, and alleviated the pancreas and kidney injury aggravated by high fluid volume in SAP. Therefore, endothelial glycocalyx protection might be a new strategy in the treatment of SAP.
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Augmenting the biological function of adipose-derived stromal cells (ASCs) is a promising approach to promoting tissue remodeling in regenerative medicine. Here, we examined the effect of ginsenoside Rg1 on the paracrine activity and adipogenic differentiation capacity of human breast ASCs (hbASCs) in vitro. hbASCs were isolated and characterized in terms of stromal cell surface markers and multipotency. Third-passage hbASCs were cultured in basic media only or basic media containing different concentrations of G-Rg1 (0.1-100 µM). Cell proliferation was assessed by CCK-8 assay. Paracrine activity was assessed using ELISA. Gene expression was measured by qRT-PCR. Adipogenic differentiation capacity was evaluated by Oil red O staining. We found that hbASCs differentiated into adipocytes, osteoblasts, and chondrocytes in appropriate induction culture medium. hbASCs showed expression of CD29, CD44, CD49d, CD73, CD90, CD105, and CD133 but not CD31 and CD45 surface markers. G-Rg1 increased hbASC proliferation and adipogenic differentiation capacity at lower concentrations (0.1-1 µM) and had the opposite effects at higher concentrations (10-100 µM), while enhanced paracrine activity was observed in all experimental groups compared with control group, and the activation effect of lower concentration G-Rg1 was greater than at higher concentration. These results indicate that G-Rg1 can enhance the proliferation, paracrine activity, and adipogenic differentiation capacity of hbASCs within a certain concentration range. Therefore, the use of G-Rg1 may be beneficial to ASC-assisted fat graft regeneration and soft tissue engineering.
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Adipogenia/efeitos dos fármacos , Tecido Adiposo , Mama , Diferenciação Celular/efeitos dos fármacos , Ginsenosídeos/farmacologia , Comunicação Parácrina/efeitos dos fármacos , Células-Tronco , Tecido Adiposo/citologia , Tecido Adiposo/metabolismo , Adulto , Mama/citologia , Mama/metabolismo , Células Cultivadas , Relação Dose-Resposta a Droga , Feminino , Humanos , Células-Tronco/citologia , Células-Tronco/metabolismoRESUMO
AIM: To investigate the mechanisms by which Sheng-jiang powder (SJP) ameliorates obesity-induced pancreatic inflammatory injury. METHODS: Sprague-Dawley rats were randomized into three groups: normal group (NG), obese group (HLG), or SJP treatment group (HSG). Obesity was induced by feeding a high-fat diet in the HLG and HSG, while the NG received standard chow. Rats were euthanized after 12 wk, and blood and pancreatic tissues were collected for histopathological analyses. Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and transforming growth factor beta (TGF-ß) expression, serum triglyceride and adiponectin levels, and apoptosis in pancreatic acinar cells were assessed. A high-fat AR42J acinar cell injury model was established using very low-density lipoprotein (VLDL). AR42J acinar cell culture supernatant, treated with different interventions, was applied to seven groups of pancreatic stellate cells (PSCs). The proliferation of PSCs and the expression of fibronectin and type I collagenase were assessed. RESULTS: Compared with the NG, we found higher pathological scores for pancreatic tissues, lower serum adiponectin levels, higher expression levels of NF-κB in pancreatic tissues and TGF-ß in pancreatic inflammatory cells, and increased apoptosis among pancreatic acinar cells for the HLG (P < 0.05). Compared with the HLG, we found reduced body weight, Lee's index scores, serum triglyceride levels, and pathological scores for pancreatic tissues; higher serum adiponectin levels; and lower expression levels of NF-κB, in pancreatic tissue and TGF-ß in pancreatic inflammatory cells for the HSG (P < 0.05). The in vitro studies showed enhanced PSC activation and increased expression levels of fibronectin and type I collagenase after SJP treatment. An adenosine 5'-monophosphate-activated protein kinase (AMPK) inhibitor inhibited PSC activation. CONCLUSION: SJP may ameliorate obesity-induced pancreatic inflammatory injury in rats by regulating key molecules of the adiponectin-AMPK signalling pathway.
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Proteínas Quinases Ativadas por AMP/metabolismo , Medicamentos de Ervas Chinesas/farmacologia , Obesidade/complicações , Pancreatite/tratamento farmacológico , Transdução de Sinais/efeitos dos fármacos , Proteínas Quinases Ativadas por AMP/antagonistas & inibidores , Células Acinares , Adiponectina/metabolismo , Animais , Linhagem Celular , Dieta Hiperlipídica/efeitos adversos , Modelos Animais de Doenças , Medicamentos de Ervas Chinesas/uso terapêutico , Fibrose , Humanos , Masculino , Obesidade/etiologia , Pâncreas/efeitos dos fármacos , Pâncreas/patologia , Pancreatite/etiologia , Pancreatite/patologia , Distribuição Aleatória , Ratos , Ratos Sprague-DawleyRESUMO
A new instrument, furnished with hydrogen clearance technique for measuring local blood-flow, was designed by use of new electronic components and a microcontroller. The corresponding program was developed. The curve of hydrogen clearance was sampled automatically by microcomputer, fitted into an exponential function by least square method, and then the local blood-flow was calculated. The cerebral blood-flow in the rat's striatum had been measured using the system. The fitted curve corresponds with the curve of hydrogen clearance and the obtained parameter was correct. The design of the instrument was reasonable. It can work reliably and stably. The calculated results are more accurate and they can be acquired more quickly, because the curve of hydrogen clearance is automatically sampled and analyzed by the microcomputer.
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Circulação Cerebrovascular/fisiologia , Hidrogênio/análise , Monitorização Fisiológica/instrumentação , Fluxo Sanguíneo Regional/fisiologia , Processamento de Sinais Assistido por Computador , Animais , Desenho de Equipamento , Hidrogênio/farmacocinética , Masculino , Microcomputadores , Ratos , Ratos Wistar , Reologia/instrumentaçãoRESUMO
AIM: To study the effects of the 50 Hz-filter circuit in a microelectrode amplifier on cardiac action potential waveform and parameters. METHODS: Cardiac action potential signals were fed into a microcomputer through a glass microelectrode, a microelectrode amplifier, a differentiator and A/D converter. The cardiac action potential signals were recorded and analyzed with 50 Hz-filter circuit and without it, and the frequency spectrum in the signals was analyzed with the fast Fourier transformation. RESULTS: When the 50 Hz-filter circuit was used, the phase 0 of the potential waveform was seriously distorted and prolonged. The maximal rate of depolarization at the phase 0 was cut down, while the other parameters were not effected. CONCLUSION: There has already been much 50 Hz element in the action potential waveform. During amplifying the cardiac action potential signal, the 50 Hz-filter circuit should not be turned on. Otherwise, the experiment results will be effected.