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Objective: To explore the basic characteristics of conventional echocardiography of apical hypertrophic cardiomyopathy (ApHCM) patients complicating with left ventricular apical aneurysm (LVAA). Methods: This is a retrospective study. Patients who underwent echocardiography and cardiac magnetic resonance (CMR) and were diagnosed with ApHCM complicated with LVAA by CMR at Fuwai Hospital, Chinese Academy of Medical Sciences from August 2012 to July 2017 were enrolled. According to whether LVAA was detected by echocardiography, the enrolled patients were divided into two groups: LVAA detected by echocardiography group and LVAA not detected by echocardiography group. Clinical data of the two groups were compared to analyze the causes of missed diagnosis by echocardiography. Results: A total of 21 patients were included, of whom 67.0% (14/21) were males, aged (56.1±16.5) years. Patients with chest discomfort accounted for 81.0% (17/21), palpitation 38.1% (8/21), syncope 14.3% (3/21). ECG showed that 21 (100%) patients had ST-T changes and 18 (85.7%) had deep T-wave invertion. Echocardiography revealed ApHCM in 17 cases (81.0%) and LVAA in 7 cases (33.3%). The mean left ventricular apical aneurysm diameter was 33.0 (18.0, 37.0) mm, and left ventricular ejection fraction was (66.5±6.6) %, and left ventricular apex thickness was (21.0±6.3) mm. Left ventricular outflow tract obstruction was presented in 4 cases and middle left ventricular obstruction in 10 cases. The mean left ventricular apical aneurysm diameter of LVAA detected by echocardiography was greater than that of LVAA not detected by echocardiography (25.0 (18.0, 28.0) mm vs. 16.0 (12.3, 21.0) mm, P=0.006). Conclusions: Conventional echocardiography examination has certain limitations in the diagnosis of ApHCM. Smaller LVAA complicated with ApHCM is likely to be unrecognized by echocardiography. Clinicians should improve their understanding of this disease.
Assuntos
Miocardiopatia Hipertrófica Apical , Cardiomiopatia Hipertrófica , Aneurisma Cardíaco , Masculino , Humanos , Feminino , Estudos Retrospectivos , Volume Sistólico , Cardiomiopatia Hipertrófica/complicações , Cardiomiopatia Hipertrófica/diagnóstico por imagem , Função Ventricular Esquerda , Ecocardiografia , Aneurisma Cardíaco/complicações , Aneurisma Cardíaco/diagnóstico por imagemRESUMO
The incidence of obesity in the population is gradually increasing. Obesity can cause a variety of complications in the digestive system such as gastroesophageal reflux disease, and impacts the integrity of the esophageal mucosal barrier and esophageal motility. However, not many studies have focused on the effect of varying degrees of obesity on the esophagus. A total of 611 participants were included in this study. We divided them into three groups according to their body mass index (BMI): the normal weight group, the overweight group, and the obesity group. We performed a retrospective comparison between groups based on indicators from high resolution esophageal manometry (HREM) and 24-hour pH impedance monitoring, and did a correlation analysis on multiple indicators such as esophageal mucosal barrier, esophageal motility, and acid reflux. The mean nocturnal baseline impedance (MNBI) in the overweight and obesity groups was lower than that in the normal group. The MNBI of the subjects in Z5-Z6 channels in the overweight group was significantly lower than that in the normal group. With respect to Z3-Z6 channels, MNBI values in the obesity group were significantly lower than those in the normal group. 'The acid exposure time (AET), the DeMeester scores (DMS) and 24-hour total reflux episodes was significantly higher in the obesity group than those in the normal and overweight groups. The upper esophageal sphincter (UES) residual pressure, and intrabolus pressure (IBP) in the overweight and obesity groups were significantly higher than those in the normal group. In addition, lower esophageal sphincter (LES) resting pressure, and esophagogastric junction contractile integral (EGJ-CI) in the obesity group were significantly higher than those in the normal group. We found that increase in body weight affected the integrity of esophageal mucosa, and different degrees of increase associated with different degrees and different aspects of changes in esophageal motility.
Assuntos
Refluxo Gastroesofágico , Sobrepeso , Humanos , Estudos Retrospectivos , Refluxo Gastroesofágico/diagnóstico , Obesidade/diagnóstico , Obesidade/complicaçõesRESUMO
The majority of high-grade serous ovarian cancers (HGSCs) are deficient in homologous recombination (HR) DNA repair, most commonly due to mutations or hypermethylation of the BRCA1/2 genes. We aimed to discover how BRCA1/2 mutations shape the cellular phenotypes and spatial interactions of the tumor microenvironment. Using a highly multiplex immunofluorescence and image analysis we generate spatial proteomic data for 21 markers in 124,623 single cells from 112 tumor cores originating from 31 tumors with BRCA1/2 mutation (BRCA1/2mut), and from 13 tumors without alterations in HR genes. We identify a phenotypically distinct tumor microenvironment in the BRCA1/2mut tumors with evidence of increased immunosurveillance. Importantly, we report a prognostic role of a proliferative tumor-cell subpopulation, which associates with enhanced spatial tumor-immune interactions by CD8+ and CD4 + T-cells in the BRCA1/2mut tumors. The single-cell spatial landscapes indicate distinct patterns of spatial immunosurveillance with the potential to improve immunotherapeutic strategies and patient stratification in HGSC.
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Proteína BRCA1/metabolismo , Proteína BRCA2/metabolismo , Carcinoma Epitelial do Ovário/imunologia , Cistadenocarcinoma Seroso/imunologia , Neoplasias Ovarianas/imunologia , Microambiente Tumoral/imunologia , Proteína BRCA1/genética , Proteína BRCA2/genética , Linfócitos T CD4-Positivos , Linfócitos T CD8-Positivos , Carcinoma Epitelial do Ovário/genética , Cistadenocarcinoma Seroso/genética , Feminino , Genes BRCA1 , Genes BRCA2 , Genótipo , Recombinação Homóloga , Humanos , Mutação , Neoplasias Ovarianas/genética , Prognóstico , ProteômicaRESUMO
To analyze the clinical data of a case of acute emamectin·chlorfenapyr poisoning in Guangzhou 12th People's Hospital in 2019. The patient developed high fever and night sweats, and gradually became unconscious. The patient died after 5 days of treatment. The toxicity and mortality of emamectin·chlorfenapyr were high. For acute poisoning patients, in addition to conventional symptomatic treatment, early blood purification treatment should be actively carried out.
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Dissacarídeos/intoxicação , Inseticidas/intoxicação , Ivermectina/análogos & derivados , Intoxicação/diagnóstico , Piretrinas/intoxicação , Humanos , Ivermectina/intoxicaçãoRESUMO
Objective: To explore the progress of small shadow and the change of lung function in pneumoconiosis with positive autoantibody, so as to provide basis for clinical treatment of pneumoconiosis. Methods: A total of 756 patients were admitted to the pneumoconiosis department of the Guangzhou Occupational Disease Prevention Hospital from January 1, 2013 to June 1, 2019. The patients with combined infection were excluded. According to whether the autoantibody was positive, they were divided into positive group and negative group, 25 cases in each group. Follow-up observation of X-ray chest radiographs, chest CT, forced expiratory volume in one second (FEV(1)) and forced expired flow at 50% of FVC (MEF(50)) of pneumoconiosis patients for 5 years, to analyze the influence of positive autoantibody on the morphology of X-ray chest film, the pneumoconiosis promotion in 5 years and lung function. Results: There were 22 males and 3 females in the autoantibody positive group, aged 53.14±10.51 years. In the autoantibody negative group, there were 23 males and 2 females, aged 53.88±8.10 years. During the 5-year observation period, there was no significant difference of small shadow shape, pneumoconiosis stage, and the pneumoconiosis promotion in 5 years between the autoantibody positive group and the autoantibody negative group (P>0.05). However, the increment of small shadow area in the autoantibody positive group was higher than that in the autoantibody negative group (P<0.05). FEV(1) and MEF(50) of the autoantibody positive group were significantly lower than those of the autoantibody negative group in the fourth and third years, respectively (P<0.05). Positive autoantibody was negatively correlated with FEV(1) and MEF(50) (P<0.05). Conclusion: The positive autoantibody can't promote the progress of X-ray, but show more small shadows on chest CT; the positive autoantibody may aggravate the decline of lung function.
Assuntos
Pulmão , Pneumoconiose/imunologia , Adulto , Feminino , Seguimentos , Volume Expiratório Forçado , Humanos , Masculino , Pessoa de Meia-Idade , Testes de Função RespiratóriaRESUMO
Objective: To analyze the influencing factors of acute kidney injury (AKI) in patients after cardiac surgery using levosimendan or dobutamine, and explore the effect of positive inotropic drugs on AKI. Methods: The clinical data of 417 patients undergoing cardiac surgery from January to June 2018 in Beijing Anzhen Hospital and treated with levosimendan or dobutamine during perioperative period were retrospectively reviewed and collected. Patients were divided into AKI group and non-AKI group according to whether AKI occurred. Univariate logistic regression analysis was used to analyze the factors related to the occurrence of AKI. The statistically significant factors (P<0.05) were further included in the multivariate logistic regression analysis. Results: Totally, 417 patients were enrolled in the study, with a mean age of (58.2±10.4) years old and a male rate of 65.0% (n=271), and the AKI incidence rate was 25.2% (105/417). Univariate logistic regression analysis showed that male, chronic kidney disease, high serum creatinine level in preoperative period, aortic obstruction time ≥ 120 minutes and extracorporeal circulation time ≥ 120 minutes were risk factors for AKI (all P<0.05). Vasodilator and levosimendan treatment during perioperative period were protective factors (P<0.05). Multivariate logistic regression analysis showed that chronic kidney disease (OR=17.291, 95%CI: 4.335-68.960, P<0.001) and high serum creatinine level (OR=1.097, 95%CI: 1.074-1.121, P<0.001) in preoperative period were independent risk factors for AKI. Perioperative application of levosimendan (OR=0.533, 95%CI: 0.288-0.984, P=0.044) was an independent protective factor. Conclusions: Risk factors for AKI after cardiac surgery include chronic kidney disease and high serum creatinine level in preoperative period. The use of levosimendan during preoperative period has the potential effect to protect against AKI.
Assuntos
Injúria Renal Aguda , Procedimentos Cirúrgicos Cardíacos , Idoso , Feminino , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias , Período Pós-Operatório , Estudos Retrospectivos , Fatores de RiscoRESUMO
BACKGROUND: Acute stroke is the third leading cause of death in Taiwan. Although statin therapy is widely recommended for stroke prevention, little is known about the epidemiology of statin therapy after acute ischemic stroke (AIS) in Taiwan. To investigate the effects of statin therapy on recurrent stroke, intracranial hemorrhage (ICH), coronary artery disease (CAD), cost of hospitalization and mortality, we conducted a nationwide population-based epidemiologic study. METHODS: Cases of AIS were identified from the annual hospitalization discharge diagnoses of the National Health Insurance Research Database with the corresponding International Classification of Diseases, ninth revision codes from January 2001 to December 2010. We divided the AIS patients into three groups: non-statin, pre-stroke statin and post-stroke statin. RESULTS: A total of 422 671 patients with AIS (including 365 419 cases in the non-statin group, 22 716 cases in the pre-stroke statin group and 34 536 cases in the post-stroke statin group) were identified. When compared to the non-statin group, both statin groups had a lower recurrent stroke risk [pre-stroke statin: odds ratio (OR) = 0.84; 95% confidence interval (CI) = 0.82-0.87; P < 0.0001; post-stroke statin: OR = 0.89; 95% CI = 0.86-0.91; P < 0.0001], lower ICH risk (pre-statin: OR = 0.75; 95% CI = 0.69-0.82; P < 0.0001; post-stroke statin: OR = 0.75; 95% CI = 0.71-0.81; P < 0.0001), and a lower mortality rate (pre-stroke statin: OR = 0.56; 95% CI = 0.53-0.59; P < 0.0001; post-stroke statin: OR = 0.51; 95% CI = 0.48-0.53; P < 0.0001). In terms of CAD, only the post-statin group had a lower risk (OR = 0.81; 95% CI = 0.79-0.84; P < 0.0001) than the non-statin group. The post-statin group had the lowest 1-year medical costs after index discharge among the three groups. CONCLUSIONS: Statin therapy reduced the risks of recurrent stroke, CAD, ICH and the first year mortality in patients after AIS. Treatment with statin therapy after AIS is a cost-effective strategy in Taiwan.
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Isquemia Encefálica/tratamento farmacológico , Inibidores de Hidroximetilglutaril-CoA Redutases/uso terapêutico , Acidente Vascular Cerebral/tratamento farmacológico , Idoso , Doença da Artéria Coronariana/epidemiologia , Doença da Artéria Coronariana/etiologia , Bases de Dados Factuais , Estudos Epidemiológicos , Feminino , Humanos , Inibidores de Hidroximetilglutaril-CoA Redutases/efeitos adversos , Hemorragias Intracranianas/induzido quimicamente , Hemorragias Intracranianas/epidemiologia , Masculino , Pessoa de Meia-Idade , Alta do Paciente/estatística & dados numéricos , Recidiva , Fatores de Risco , Acidente Vascular Cerebral/mortalidade , Acidente Vascular Cerebral/prevenção & controle , Taiwan/epidemiologia , Fatores de Tempo , Resultado do TratamentoRESUMO
Systemic lupus erythematosus (SLE) is an autoimmune connective tissue disease that affects multiple organs and diminishes a patients' quality of life. It has been suggested that interleukin 19 (IL-19) is engaged in intercellular signal transduction, which is related to the immune response and the local inflammatory reaction. Single nucleotide polymorphisms (SNPs) have been used to explore the genetic basis underlying the pathogenesis of SLE. In this study, we investigated the potential correlation between the functional IL19 SNP rs2243188 and SLE. The frequency of allele C in rs2243188 was lower in the SLE population, particularly when the dominant inheritance model was applied. There was also a significant difference in the allele C frequency between the lupus nephritis (LN) and non-LN groups in both the dominant and recessive inheritance models. In addition, we identified significant differences in the serum IL-19 levels between the different classes of SLE. Although this study is still at the preliminary stage, the correlations between the IL19 SNP and SLE, and between the IL-19 levels and the different subclasses of SLE provide a reference for further exploration.
Assuntos
Interleucinas/genética , Nefrite Lúpica/genética , Polimorfismo de Nucleotídeo Único , Adolescente , Adulto , Estudos de Casos e Controles , Feminino , Frequência do Gene , Humanos , Interleucinas/sangue , Nefrite Lúpica/sangue , Masculino , Pessoa de Meia-IdadeRESUMO
In this study, the effect of host density, host, and parasitoid ages in choice and no-choice tests on the parasitism performance of Tetrastichus brontispae Ferriere, one of the major parasitoid of Brontispa longissima (Gestro), was investigated in the laboratory. The results revealed that an increased host density resulted in no increased parasitism of B. longissima by T. brontispae; the optimal host density was three host pupae per parasitoid when considering the costs for mass rearing. Moreover, parasitoid age was quite crucial for effective parasitism and affected the emergence rate. Although 2-h to 4-day-old parasitoids successfully parasitized the host pupae, younger parasitoids (within 2-day-old) presented higher parasitism capacity than older parasitoids. More importantly, both choice and no-choice tests confirmed that all host stages tested from 2-h to 4-day-old were suitable for T. brontispae parasitization, although 2-h to 2-day-old hosts were preferred. We also demonstrated that sex ratio, emergence rate, and egg to adult developmental time were not influenced by host density, parasitoid, and host age in both choice and no-choice tests. Our data will allow for more accurate prediction and interpretation on the parasitization by T. brontispae, supporting mass-production initiatives and mass release in programs of B. longissima.
Assuntos
Besouros/parasitologia , Himenópteros/patogenicidade , Animais , Interações Hospedeiro-Parasita , Pupa , VespasRESUMO
BACKGROUND: Tuberous sclerosis complex (TSC) is caused by mutations in TSC1 and TSC2, leading to mammalian target of rapamycin hyperactivation. Patients with TSC develop hamartomas in brain, lungs, liver and skin. Two epidemiological studies, performed in Minnesota, U.S.A., have estimated the incidence of TSC to be 0·28-0·56 per 100 000 person-years (PY), based on < 12 patients. Furthermore, whether common comorbidities are associated with this rare disease is not known. OBJECTIVES: To estimate the incidence of TSC and investigate the associations of TSC with other comorbidities, including diabetes, peptic ulcers, stroke and myocardial infarction. METHODS: We estimated the incidence and prevalence of TSC and its comorbidities from 1997 to 2010, based on the Catastrophic Illness Certificate disease database and a beneficiary cohort of 1 million people. RESULTS: The incidence of TSC in Taiwan is 0·153 per 100 000 PY. The number of patients identified with TSC in Taiwan doubled from 206 in 2006 to 471 in 2010. In 2010, the prevalence of TSC in Taiwan was estimated to be 1·58 in 100 000. We confirmed that female patients with TSC are more likely to develop renal tumours than male patients. Surprisingly, patients with TSC have a significantly decreased risk of developing peptic ulcers compared with controls. CONCLUSIONS: This is the first large-scale and longitudinal incidence study of TSC. This study provides compelling evidence that TSC mutations in humans are associated with a decreased risk of peptic ulcers.
Assuntos
Esclerose Tuberosa/epidemiologia , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Demência/epidemiologia , Métodos Epidemiológicos , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Neoplasias/epidemiologia , Úlcera Péptica/epidemiologia , Estudos Retrospectivos , Convulsões/epidemiologia , Taiwan/epidemiologia , Esclerose Tuberosa/complicações , Adulto JovemRESUMO
BACKGROUND AND PURPOSE: Our aim was to investigate the influence of admission dehydration on the discharge outcome in acute ischaemic and hemorrhagic stroke. METHODS: Between January 2009 and December 2011, 4311 ischaemic and 1371 hemorrhagic stroke patients from the stroke registry of Chang Gung healthcare system were analyzed. The eligible patients were identified according to inclusion/exclusion criteria. In total, 2570 acute ischaemic and 573 acute hemorrhagic stroke patients were finally recruited. According to the blood urea nitrogen (BUN) to creatinine (Cr) ratio (BUN/Cr), these patients were divided into dehydrated (BUN/Cr ≥ 15) and non-dehydrated (BUN/Cr < 15) groups. Demographics, admission costs and discharge outcomes including modified Rankin scale (mRS) and Barthel index (BI) were examined. Data were analyzed using multivariate analysis of two-stage least squares including logistic and linear regression. RESULTS: Acute ischaemic stroke with admission dehydration had higher infection rates (P = 0.006), worse discharge BI (62.8 ± 37.4 vs. 73.4 ± 32.4, P < 0.001, adjusted P < 0.001), worse mRS (2.7 ± 1.6 vs. 2.3 ± 1.5, P < 0.001, adjusted P = 0.009) and higher admission costs (2470.8 ± 3160.8 vs. 1901.2 ± 2046.8 US dollars, P < 0.001, adjusted P = 0.013) than those without dehydration. However, acute hemorrhagic stroke with or without admission dehydration showd no difference in admission costs (P = 0.618) and discharge outcomes (BI, P = 0.058; mRS, P = 0.058). CONCLUSION: Admission dehydration is associated with worse discharge outcomes and higher admission costs in acute ischaemic stroke but not in hemorrhagic stroke.
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Isquemia Encefálica/complicações , Desidratação , Hospitalização/economia , Admissão do Paciente/economia , Acidente Vascular Cerebral/etiologia , Idoso , Idoso de 80 Anos ou mais , Custos e Análise de Custo , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Alta do Paciente , Valor Preditivo dos Testes , Sistema de Registros , Estudos Retrospectivos , Índice de Gravidade de Doença , Estatísticas não Paramétricas , Resultado do TratamentoRESUMO
Our previous study has shown that aging and hypertension may alter apparent diffusion coefficient (ADC) and cerebral blood flow (CBF) and increase ischemic susceptibility in the non-ischemic rat brain. The present study wishes to further investigate whether aging and hypertension may influence cerebral diffusion/perfusion and increase ischemic susceptibility in the ischemic brain. Brain magnetic resonance (MR) imaging was examined 1day before and 1 and 7days after bilateral common carotid artery occlusion. Young and middle-aged normotensive Wistar-Kyoto rats and young and middle-aged spontaneously hypertensive rats (SHRs) were studied. Infarction occurred mainly in the parietal cortex and was larger in middle-aged SHRs than the other three groups (P<0.05). In pre-operation, ADC was higher and CBF was lower in middle-aged/hypertensive rats than young/normotensive rats (P<0.05). The ADC was higher in the parietal cortex of the rats with infarction at 7days when compared to the rats without infarction [receiver operating characteristic curve (ROC), P=0.001; binary logistic regression (BLR), P=0.006]. However, there was no difference in the hippocampus and thalamus. At day 1 post-operation, CBF reduced and ADC/CBF ratio elevated significantly in the parietal cortex of the rats with infarction when compared to the rats without infarction (CBF: ROC, P=0.002; BLR, P=0.017. ADC/CBF ratio: ROC, P=0.001; BLR, P=0.018). Our results demonstrated that pre-operation ADC and post-operation CBF and ADC/CBF ratio can be used as good MR markers in the prediction of ischemic susceptibility after cerebral hypoperfusion.
Assuntos
Envelhecimento , Isquemia Encefálica/diagnóstico , Circulação Cerebrovascular/fisiologia , Suscetibilidade a Doenças , Hipertensão/fisiopatologia , Animais , Pressão Sanguínea/fisiologia , Peso Corporal/fisiologia , Infarto Encefálico/etiologia , Circulação Cerebrovascular/genética , Modelos Animais de Doenças , Frequência Cardíaca/fisiologia , Estudos Longitudinais , Imageamento por Ressonância Magnética , Masculino , Ratos , Ratos Endogâmicos SHR , Ratos Endogâmicos WKYRESUMO
A novel monolithic mechanical bender has been designed and fabricated to meet the requirements of an active polynomial grating in a new soft X-ray scattering and emission beamline at the National Synchrotron Radiation Research Center, Taiwan. This compact bender achieves nearly fixed center point under different bending conditions. Moreover, the compact bender can be bent to a desirable third-order polynomial surface profile to cancel the defocus and coma aberrations using two PZT actuators. Theoretical analysis reveals that the grating has unprecedented spectral resolving power. A detailed mechanical analysis has been conducted and a prototype bender was fabricated and tested. The results indicate that the performance of the bender is excellent and is therefore suitable to be used in the active grating.
Assuntos
Análise de Falha de Equipamento , Óptica e Fotônica/instrumentação , Espalhamento de Radiação , Síncrotrons/instrumentação , Difração de Raios X/instrumentação , Difração de Raios X/métodos , Desenho Assistido por Computador , Elasticidade , Desenho de Equipamento , Retroalimentação , Movimento (Física) , Estimulação Física/instrumentação , Estresse Mecânico , TransdutoresRESUMO
AIM: To study the gating kinetics of voltage-dependent K+ channels i n clonal pheochromocytoma (PC12) cells and the effect of nerve growth factor (NGF) on it. METHODS: Outward currents of K+ channel were recorded in PC12 cells cultured with or without NGF using cell-attached patch-clamp technique. The kinetic features of K+ channel and the effect of NGF on them were analyzed based on t he fractal model. RESULTS: The fractal dimension D for the closed durations of K+ channel in PC12 cells cultured without NGF was proportional to the absolute value of the pipette potential (Vp). Whereas the fractal dimension D' was inversely proportional to it. Under pipette potentials of 0, -30, -50, and -70 mV, the values of D were 1.75, 1.88, 1.95, and 2; and of D' were 1.51, 1.40, 1.34, and 1.23. After the addition of NGF the changes in the fractal dimensions became more complex. At the same pipette potential, fractal dimensions for K+ channel in PC12 cells cultured with NGF for both the open and closed durations were not greater than those in PC12 cells cultured without NGF. The kinetic setpoints for both the close and open durations did not vary with the pipette potential with values as follows: A (without NGF) = 0.29 +\ -0.05, A(with NGF) = 0.71 +\- 0.06, A' without NGF) = 0.110 +\- 0.020, and A' (with NGF) = 0.38 +\- 0.08. CONCLUSION: The voltage dependence of D (without NGF) increases the probability of the channel for remaining closed for long durations as the patch is depolarized, and that of D' (without NGF) decreases the probability of the channel for remaining open for long durations as the patch is depolarized. The addition of NG F in the PC12 cell culture accelerates the dynamic process of the K+ channel occurring over long time scales.
Assuntos
Fator de Crescimento Neural/farmacologia , Canais de Potássio de Abertura Dependente da Tensão da Membrana/efeitos dos fármacos , Animais , Fractais , Células PC12 , Técnicas de Patch-Clamp , RatosRESUMO
The single ion channel signal is stochastic ionic current on the order of 1 pA recorded by patch clamp. Because the weakness of the signal, the background noise always dominates in the recordings, the threshold detector traditionally used in patch clamp to denoise and restore the channel signal can't work satisfactorily. This problem was analyzed mathematically, and a signal restoring and parameters estimating scheme called HMM algorithm was studied. The algorithm has been validated by simulation and the results suggest it performs effectively in the situation of low signal to noise ratio where the threshold detector fails completely.
Assuntos
Algoritmos , Canais Iônicos/fisiologia , Cadeias de Markov , Técnicas de Patch-Clamp/métodos , Teorema de Bayes , Funções VerossimilhançaRESUMO
In federal courts, the admissibility of scientific expert testimony in the last century has been governed by three major standards. The first of these standards, the "general acceptance" test, arose from the 1923 Frye v. United States (Frye) and required that any technique or method introduced in court be generally accepted by the relevant community of scientists. The more liberal "relevancy" standard of the Federal Rules of Evidence was enacted in 1975, and required the expert witness to be qualified by knowledge, skill, experience, training, or education. Finally, the "reliability" standard stated in the Daubert v. Merrell Dow Pharmaceuticals, Inc. (Daubert) opinion was handed down by the U.S. Supreme Court in 1993, supplanting the Frye general acceptance test as the sole determining factor in considering the admissibility of scientific expert testimony, and suggesting falsifiability, peer review and publication, and error rate as additional factors useful in evaluating a scientific technique. Changing views on expert testimony have also resulted in published criticisms of several forensic fields, especially those with subjective components. The first such field to be questioned, which also has been the subject of great debate, is expert handwriting identification. Challenges leveled against handwriting identification began with a law review article published in 1989 (and two subsequent articles); other challenges have been based on the requirements outlined in the Federal Rules of Evidence and Daubert. These challenges resulted in several court opinions with disparate views of handwriting identification, though testimony by an expert in the field was not rejected. In U.S. v. Starzecpyzel, handwriting evidence was admitted as nonscientific expert testimony under the Federal Rules of Evidence after failing a review under the factors outlined in Daubert. In U.S. v. Velasquez (Velasquez), the testimony of a document examiner was accepted, while the testimony of an expert critic of handwriting identification was rejected by the district court; however, on appeal, the Third Circuit held that both witnesses met the requirements of the Federal Rules of Evidence, and thus both testimonies were admissible. U.S. v. Jones (Jones) demonstrated yet another situation, where handwriting identification was challenged under Daubert. There the court found that because handwriting identification was never viewed as scientific evidence under Frye, it should not therefore be reviewed under Daubert. The Jones court admitted handwriting identification as nonscientific evidence, but stated that admissibility of nonscientific evidence should be governed by the facts of future cases. After some time and many other opinions on the admissibility of expert testimony under Daubert, several federal circuits permitted review of nonscientific expert testimony under the factors outlined in Daubert, while other federal circuits restricted such reviews only to purportedly scientific testimonies. In the latter arenas, determining whether handwriting identification was a scientific field or not had bearing on how it was reviewed for admissibility, if it was reviewed at all. This situation ended in March 1999 with the U.S. Supreme Court opinion of Kumho Tire Co., Ltd. v. Carmichael (Kumho), which held that the Daubert factors may be used for review of all expert testimony as the courts see fit, regardless of whether the field is considered scientific. In the wake of Kumho, two other cases challenged handwriting identification: U.S. v. Paul (Paul) and U.S. v. Hines (Hines). The Paul case, like Velasquez, dealt with exclusion of an expert critic of handwriting identification, and also like Velasquez, the court appeared to rely on the Federal Rules of Evidence rather than the factors outlined in Daubert to form its judgment. Hines, however, represented a significant departure from earlier cases, as handwriting identification was partially excluded in that the document examiner was permitted to testify to similarities and differences but was not allowed to opine as to the authorship. In sum, the federal courts are currently evaluating the admissibility of handwriting identification in a variety of ways. Though handwriting identification continues to be widely admitted as a form of expert testimony, the recent changes in admissibility requirements and challenges from the legal community have generated a climate where admissibility should no longer to be taken for granted. Because Kumho is a relatively recent case, its long-term effects on the admissibility of many fields of forensic science, including handwriting identification, are yet unknown.
RESUMO
This paper introduces a data acquisition circuit that is able to acquire ventricular late potentials and standard 12-lead electrocardiogram signals. This circuit adopts time interruption acquisition, it has the characteristics of programmed gain, isolated ground, low-noise, high-CMRR, collecting data for a long time.
Assuntos
Eletrocardiografia/instrumentação , Eletrônica , Processamento de Sinais Assistido por Computador/instrumentação , Função Ventricular , Desenho de Equipamento , Humanos , Design de SoftwareRESUMO
A system for acquisiting event-related-potential signalsis presented, making use of random-sequences visial symbols. ATMEL AT89C51 controls Max 186 serial conversion and interface Max202 to serially send data to host computer for poct processing.