RESUMO
PURPOSE: To evaluate the diagnostic performance of multi-modality functional imaging in differentiating malignant and benign thyroid 18F-fluorodeoxyglucose (18F-FDG) incidentaloma. METHODS: This study included 87 patients with thyroid 18F-FDG incidentalomas detected by 18F-FDG- positron emission tomography/computed tomography (18F-FDG-PET/CT) and diagnosed at surgery or biopsy, who received 18F-FDG-PET/CT, diffusion-weighted MR imaging (DWI) and ultrasound elastography (USE). The metabolic tumor volume (MTV), total lesion glycolysis (TLG), apparent diffusion coefficient (ADC) values and ultrasound elasticity scores of thyroid 18F-FDG incidentalomas were measured and compared in benign and malignant thyroid incidentalomas. The differences of malignant and benign thyroid incidentalomas were tested by χ2 test, Fisher's exact test, t test, or Mann-Whitney U test. The diagnostic performance was evaluated and optimal cut-off values were determined in distinguishing malignant from benign thyroid incidentalomas by receiver operating characteristic curve analysis. RESULTS: MTV, TLG and USE scores of malignant thyroid incidentalomas were significantly higher than benign; but ADC value was significantly lower. We defined the functional imaging parameters TLG < 2.48, ADC > 1.80 × 10-3mm2/s, and USE score of 1 as markers of benign thyroid incidentalomas and each scored -1 point; TLG ≥ 2.48, ADC ≤ 1.80 × 10-3mm2/s, and USE score of 4 as markers of malignancy and each scored 1 point. Combined multi-functional imaging parameters achieved the highest performance (84.6% sensitivity and 97.1% specificity) for distinguish malignant from benign thyroid incidentaloma with AUC 0.957 (95% CI 0.917, 0.997). CONCLUSIONS: Functional imaging might help to distinguishing malignant from benign thyroid 18F-FDG incidentalomas, and combined multi-functional imaging parameters could improve it.
Assuntos
Fluordesoxiglucose F18 , Achados Incidentais , Imagem Multimodal/métodos , Compostos Radiofarmacêuticos , Neoplasias da Glândula Tireoide/diagnóstico por imagem , Diagnóstico Diferencial , Imagem de Difusão por Ressonância Magnética , Técnicas de Imagem por Elasticidade , Glicólise , Humanos , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Estudos Retrospectivos , Sensibilidade e Especificidade , Estatísticas não Paramétricas , Neoplasias da Glândula Tireoide/metabolismo , Carga TumoralRESUMO
This study investigated the efficacy and feasibility of inducing the differentiation of bone marrow-derived mesenchymal stem cells (BMSCs) into hepatocyte-like cells in vitro using Sprague Dawley rats, as a model of hepatocyte generation for cell transplantation. BMSCs were isolated and grown using the adherent method and exposed to 5 or 10% liver tissue homogenate, before being collected for analysis after 0, 7, 14, and 21 days. Immunofluorescence and western blotting were employed to detect the liver-specific markers a-fetoprotein (AFP) and albumin (ALB). Supernatant urea content was also measured to verify that differentiation had been induced. After 7 days in the presence of 10% liver tissue homogenate, BMSCs demonstrated hepatocyte-like morphological characteristics, and with prolonged culture time, liver-specific markers were gradually produced at levels indicating cell maturation. AFP expression peaked at 14 days then began to decrease, while both urea and ALB levels increased with induction time. Overall, marker expression in the 5% homogenate group was less than or equal to the 10% group at each time point. Thus, in a rat model, liver tissue homogenate obtained from partial hepatectomy can induce the differentiation of BMSCs into hepatocyte-like cells. This method is simple, feasible, and has remarkable real-world application potential.
Assuntos
Diferenciação Celular , Hepatócitos/citologia , Fígado/metabolismo , Células-Tronco Mesenquimais/citologia , Albuminas/genética , Albuminas/metabolismo , Animais , Células Cultivadas , Proteínas Fetais/genética , Proteínas Fetais/metabolismo , Hepatócitos/metabolismo , Fígado/química , Masculino , Células-Tronco Mesenquimais/metabolismo , Ratos , Ratos Sprague-Dawley , Frações Subcelulares/química , Frações Subcelulares/metabolismoRESUMO
The liver is the human body largest digestive and metabolic organ, and a very important immune organ. This paper discusses the location and morphology of hepatic sinusoidal endothelial cells, dendritic cells, hepatic stellate cells, and Kupffer cells in the liver and their role in regulating immune functions. Therefore, here we provide a preliminary understanding of the immune regulatory function of liver cells, and information on the occurrence and treatment of liver diseases.
Assuntos
Células Dendríticas/imunologia , Células Endoteliais/imunologia , Células Estreladas do Fígado/imunologia , Células de Kupffer/imunologia , Fígado/imunologia , Animais , Humanos , Fígado/irrigação sanguínea , Fígado/citologiaRESUMO
Many studies have shown that microRNA (miR)-133 functions as a tumor suppressor in a variety of metastatic cancers, including breast cancer, gastric cancer, and liver fibrosis. However, the influence of miR-133 on pituitary tumor malignancy has not yet been reported. The purpose of this study was to explore the role of miR-133 in pituitary tumor cell migration and invasive ability and the molecular mechanisms involved. Our findings suggest that in pituitary adenoma cell lines, through direct targeting and negative control of forkhead box C1 (FOXC1), miR-133 can inhibit pituitary adenoma cell migration and invasion. In addition, epithelial-to-mesenchymal transition can be induced by miR-133. Additionally, a negative correlation was found between FOXC1 and miR-133 expression when comparing their expression levels between cancerous tissue and adjacent normal tissue. This suggests that miR-133 can inhibit cell migration and invasion by directly targeting FOXC1, implying that miR-133 could be a potential therapeutic target for treatment of invasive pituitary adenoma.
Assuntos
Fatores de Transcrição Forkhead/metabolismo , MicroRNAs/fisiologia , Neoplasias Hipofisárias/genética , Neoplasias Hipofisárias/metabolismo , Linhagem Celular Tumoral , Movimento Celular/genética , Movimento Celular/fisiologia , Fatores de Transcrição Forkhead/genética , Regulação Neoplásica da Expressão Gênica , Humanos , MicroRNAs/genética , Reação em Cadeia da Polimerase em Tempo RealRESUMO
Accumulating evidence has suggested that high salt and potassium might be associated with vascular function. The aim of this study was to investigate the effect of salt intake and potassium supplementation on brachial-ankle pulse wave velocity (PWV) in Chinese subjects. Forty-nine subjects (28-65 years of age) were selected from a rural community of northern China. All subjects were sequentially maintained on a low-salt diet for 7 days (3.0 g/day NaCl), a high-salt diet for an additional 7 days (18.0 g/day NaCl), and a high-salt diet with potassium supplementation for a final 7 days (18.0 g/day NaCl+4.5 g/day KCl). Brachial-ankle PWV was measured at baseline and on the last day of each intervention. Blood pressure levels were significantly increased from the low-salt to high-salt diet, and decreased from the high-salt diet to high-salt plus potassium supplementation. Baseline brachial-ankle PWV in salt-sensitive subjects was significantly higher than in salt-resistant subjects. There was no significant change in brachial-ankle PWV among the 3 intervention periods in salt-sensitive, salt-resistant, or total subjects. No significant correlations were found between brachial-ankle PWV and 24-h sodium and potassium excretions. Our study indicates that dietary salt intake and potassium supplementation, at least in the short term, had no significant effect on brachial-ankle PWV in Chinese subjects.
RESUMO
Accumulating evidence has suggested that high salt and potassium might be associated with vascular function. The aim of this study was to investigate the effect of salt intake and potassium supplementation on brachial-ankle pulse wave velocity (PWV) in Chinese subjects. Forty-nine subjects (28-65 years of age) were selected from a rural community of northern China. All subjects were sequentially maintained on a low-salt diet for 7 days (3.0 g/day NaCl), a high-salt diet for an additional 7 days (18.0 g/day NaCl), and a high-salt diet with potassium supplementation for a final 7 days (18.0 g/day NaCl+4.5 g/day KCl). Brachial-ankle PWV was measured at baseline and on the last day of each intervention. Blood pressure levels were significantly increased from the low-salt to high-salt diet, and decreased from the high-salt diet to high-salt plus potassium supplementation. Baseline brachial-ankle PWV in salt-sensitive subjects was significantly higher than in salt-resistant subjects. There was no significant change in brachial-ankle PWV among the 3 intervention periods in salt-sensitive, salt-resistant, or total subjects. No significant correlations were found between brachial-ankle PWV and 24-h sodium and potassium excretions. Our study indicates that dietary salt intake and potassium supplementation, at least in the short term, had no significant effect on brachial-ankle PWV in Chinese subjects.
RESUMO
We used a simple and efficient method to construct the bicistronic eukaryotic expression vector pIRES2-NGF-VEGF165. The nerve growth factor (NGF) gene was obtained from the genomic DNA of human peripheral blood mononuclear cells by polymerase chain reaction. The NGF cDNA fragment was inserted into the multiple cloning sites of the pIRES2-EGFP vector to generate the bicistronic eukaryotic expression plasmid pIRES2-NGF-EGFP. The vascular endothelial growth factor 165 (VEGF165) gene was obtained from the pIRES2-VEGF165-EGFP plasmid by polymerase chain reaction. Next, the VEGF165 cDNA fragment was cloned into pIRES2-NGF-EGFP in place of enhanced green fluorescent protein creating the plasmid pIRES2-NGF-VEGF165. pIRES2-NGF-VEGF165 was transfected into HEK293 cells and reverse transcription-polymerase chain reaction and Western blot analysis were used to test the co-expression of double genes. The NGF and VEGF165 genes were cloned and the DNA was sequenced, which revealed that NGF and VEGF165 were consistent with the sequence recorded in GenBank. Restriction analysis showed that the NGF and VEGF165 genes were inserted into the expression vector pIRES2-EGFP. Transfection of pIRES2-NGF-VEGF165 into HEK293 cells resulted in expression of the double gene at the mRNA and protein levels. The NGF and VEGF165 coexpression plasmid provides a novel expression system, enabling further study of the functions of the NGF and VEGF165 genes.
Assuntos
Expressão Gênica , Vetores Genéticos/genética , Fator de Crescimento Neural/genética , Fator A de Crescimento do Endotélio Vascular/genética , Clonagem Molecular , Células HEK293 , Humanos , Fator de Crescimento Neural/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismoRESUMO
We used a simple and efficient method to construct a bicistronic eukaryotic expression vector pIRES2-LIF-NT-3. The leukemia inhibitory factor (LIF) and neurotrophin-3 (NT-3) genes were obtained from the genomic DNA of human peripheral blood mononuclear cells by polymerase chain reaction. The LIF cDNA fragment was inserted into the multiple cloning sites of a vector containing internal ribosome entry site and enhanced green fluorescent protein (EGFP) (pIRES2-EGFP) to generate the bicistronic eukaryotic expression plasmid pIRES2-LIF-EGFP. Next, the NT-3 cDNA fragment was cloned into pIRES2-LIF-EGFP in place of EGFP to create the plasmid pIRES2-LIF-NT-3. pIRES2-LIF-NT-3 was transfected into HEK293 cells and reverse transcription-polymerase chain reaction and Western blotting were used to test the co-expression of double genes. LIF and NT-3 genes were cloned and the DNA was sequenced. Sequencing analysis revealed that LIF and NT-3 were consistent with the sequence recorded in GenBank. Restriction analysis indicated that the LIF and NT-3 genes were inserted correctly into the expression vector pIRES2-EGFP. Following transfection of pIRES2-LIF-NT-3 into HEK293 cells, the double gene was expressed at the mRNA and protein levels. The LIF and NT-3 coexpression plasmid is a novel expression system that will enable further study of the functions of the LIF and NT-3 genes.
Assuntos
Clonagem Molecular/métodos , Fator Inibidor de Leucemia/genética , Fator Inibidor de Leucemia/metabolismo , Fatores de Crescimento Neural/genética , Fatores de Crescimento Neural/metabolismo , Vetores Genéticos , Proteínas de Fluorescência Verde/metabolismo , Células HEK293 , Humanos , Leucócitos Mononucleares/metabolismo , Neurotrofina 3 , Proteínas Recombinantes de Fusão/metabolismo , TransfecçãoRESUMO
We used a simple and efficient method to construct the bicistronic eukaryotic expression vector pIRES2-VEGF165-NT-3. The neurotrophin-3 (NT-3) gene was obtained from the genomic DNA of human peripheral blood mononuclear cells by polymerase chain reaction. The NT-3 cDNA fragment was cloned into the pIRES2-VEGF165-EGFP vector in place of enhanced green fluorescent protein (EGFP) to create the plasmid pIRES2-VEGF165-NT-3. Next, pIRES2-VEGF165-NT-3 was transfected into HEK293 cells, and reverse transcription-polymerase chain reaction and Western blotting were used to test co-expression of the double genes. The vascular endothelial growth factor 165 (VEGF165) and NT-3 genes were cloned; DNA sequencing analysis demonstrated that the VEGF165 and NT-3 sequences were the same as those recorded in GenBank. Restriction analysis indicated that the VEGF165 and NT-3 genes were correctly inserted into the expression vector pIRES2-EGFP. The double gene was expressed at both the mRNA and protein levels. The VEGF165 and NT-3 co-expression plasmid was successfully constructed, providing a novel expression system for further study of the functions of the VEGF165 and NT-3 genes.
Assuntos
Clonagem Molecular/métodos , Fatores de Crescimento Neural/genética , Fatores de Crescimento Neural/metabolismo , Fator A de Crescimento do Endotélio Vascular/genética , Fator A de Crescimento do Endotélio Vascular/metabolismo , Vetores Genéticos , Proteínas de Fluorescência Verde/metabolismo , Células HEK293 , Humanos , Leucócitos Mononucleares/metabolismo , Proteínas Recombinantes de Fusão/metabolismo , TransfecçãoRESUMO
Dietary salt intake has been linked to hypertension and cardiovascular disease. Accumulating evidence has indicated that salt-sensitive individuals on high salt intake are more likely to develop renal fibrosis. Epithelial-to-mesenchymal transition (EMT) participates in the development and progression of renal fibrosis in humans and animals. The objective of this study was to investigate the impact of a high-salt diet on EMT in Dahl salt-sensitive (SS) rats. Twenty-four male SS and consomic SS-13(BN) rats were randomized to a normal diet or a high-salt diet. After 4 weeks, systolic blood pressure (SBP) and albuminuria were analyzed, and renal fibrosis was histopathologically evaluated. Tubular EMT was evaluated using immunohistochemistry and real-time PCR with E-cadherin and alpha smooth muscle actin (α-SMA). After 4 weeks, SBP and albuminuria were significantly increased in the SS high-salt group compared with the normal diet group. Dietary salt intake induced renal fibrosis and tubular EMT as identified by reduced expression of E-cadherin and enhanced expression of α-SMA in SS rats. Both blood pressure and renal interstitial fibrosis were negatively correlated with E-cadherin but positively correlated with α-SMA. Salt intake induced tubular EMT and renal injury in SS rats, and this relationship might depend on the increase in blood pressure.
Assuntos
Pressão Sanguínea/fisiologia , Transição Epitelial-Mesenquimal/fisiologia , Rim/patologia , Ratos Endogâmicos Dahl , Cloreto de Sódio na Dieta/efeitos adversos , Actinas/genética , Albuminúria , Animais , Caderinas/genética , Fibrose , Expressão Gênica , Hipertensão/fisiopatologia , Imuno-Histoquímica , Masculino , Distribuição Aleatória , Reação em Cadeia da Polimerase em Tempo Real , Nitrato de PrataRESUMO
Dietary salt intake has been linked to hypertension and cardiovascular disease. Accumulating evidence has indicated that salt-sensitive individuals on high salt intake are more likely to develop renal fibrosis. Epithelial-to-mesenchymal transition (EMT) participates in the development and progression of renal fibrosis in humans and animals. The objective of this study was to investigate the impact of a high-salt diet on EMT in Dahl salt-sensitive (SS) rats. Twenty-four male SS and consomic SS-13BN rats were randomized to a normal diet or a high-salt diet. After 4 weeks, systolic blood pressure (SBP) and albuminuria were analyzed, and renal fibrosis was histopathologically evaluated. Tubular EMT was evaluated using immunohistochemistry and real-time PCR with E-cadherin and alpha smooth muscle actin (α-SMA). After 4 weeks, SBP and albuminuria were significantly increased in the SS high-salt group compared with the normal diet group. Dietary salt intake induced renal fibrosis and tubular EMT as identified by reduced expression of E-cadherin and enhanced expression of α-SMA in SS rats. Both blood pressure and renal interstitial fibrosis were negatively correlated with E-cadherin but positively correlated with α-SMA. Salt intake induced tubular EMT and renal injury in SS rats, and this relationship might depend on the increase in blood pressure.
Assuntos
Animais , Masculino , Pressão Sanguínea/fisiologia , Transição Epitelial-Mesenquimal/fisiologia , Rim/patologia , Ratos Endogâmicos Dahl , Cloreto de Sódio na Dieta/efeitos adversos , Albuminúria , Actinas/genética , Caderinas/genética , Fibrose , Expressão Gênica , Hipertensão/fisiopatologia , Imuno-Histoquímica , Distribuição Aleatória , Reação em Cadeia da Polimerase em Tempo Real , Nitrato de PrataRESUMO
We examined STAG-related gene (DjStag) expression in the planarian Dugesia japonica. This species is common in Far Eastern countries. The DjStag cDNA includes 1362 bp and contains a 489-bp open reading frame corresponding to a deduced protein of 162 amino acids, with a 170-bp 5'-UTR and a 703-bp 3'-UTR. Phylogenetic analysis showed that DjStag is an STAG/STAG-like member. We examined the expression pattern of DjStag in this planarian during embryonic development by whole-mount in situ hybridization. DjStag was detected in embryonic cells in the germ band at early embryo stages. The number of DjStag-positive embryonic cells increased in stage 5. Later, it was mainly expressed in lateral region parenchyma. In juveniles, extensive expression of DjStag was observed not only in the head and tail regions, but also in the parenchyma between the epidermis and the gastrodermis. We conclude that DjStag is expressed in the cellular subset that will become the neoblast cells of the adult flatworm. DjStag may play an essential role in spatial and temporal regulation during planarian embryonic development.
Assuntos
Proteínas de Helminto/genética , Proteínas Nucleares/genética , Planárias/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Clonagem Molecular , Regulação da Expressão Gênica no Desenvolvimento , Proteínas de Helminto/química , Proteínas de Helminto/metabolismo , Dados de Sequência Molecular , Proteínas Nucleares/química , Proteínas Nucleares/metabolismo , Especificidade de Órgãos , Planárias/embriologia , RNA Mensageiro/genética , RNA Mensageiro/metabolismoRESUMO
The established and adapted image biomarkers based on size for tumor burden measurement continue to be applied to hepatocellular carcinoma (HCC) as size measurement can easily be used in clinical practice. However, in the setting of novel targeted therapies and liver directed treatments, simple tumor anatomical changes can be less informative and usually appear later than biological changes. Functional magnetic resonance imaging (MRI) has a potential to be a promising technique for assessment of HCC response to therapy. In this review, we discuss various functional MRI biomarkers that play an increasingly important role in evaluation of HCC response after treatment.
Assuntos
Carcinoma Hepatocelular/patologia , Neoplasias Hepáticas/patologia , Imageamento por Ressonância Magnética/métodos , Carcinoma Hepatocelular/terapia , Humanos , Interpretação de Imagem Assistida por Computador , Neoplasias Hepáticas/terapia , Espectroscopia de Ressonância Magnética , Resultado do TratamentoRESUMO
BACKGROUND: To prospectively assess the role of the dynamic contrast-enhanced CT enhancement characteristics in distinguishing malignant form of benign solitary pulmonary nodules. METHODS: The study included 87 patients (59 men, 28 women; median age, 59 years) with 87 solitary pulmonary nodules. In all cases, dynamic CT images were obtained before and 20, 30, 45, 60, 75, 90, 120 s, 3, 5, 9, 12, 15 and 20 min after injection of contrast medium. Peak enhancement attenuation value, net enhancement attenuation value, the slope of enhancement, enhancement ratio, outflow of contrast medium (washout), washout ratio and the slope of washout ratio were assessed. Statistical analyses were performed with the Mann-Whitney test, χ(2) test, and receiver-operating characteristic curves. RESULTS: There were 52 malignant and 35 benign nodules. There were no significant differences in net enhancement value, enhancement ratio and the slope of enhancement ratio between malignant and benign nodules (P > 0.05). Malignant nodules showed smaller outflow of contrast medium than did benign nodules. With 12.4HU or lower washout as a cutoff value, the sensitivity and specificity for malignancy were 52.5 and 65.0 %, respectively. With 18.9 % or lower washout ratio as a cutoff value, sensitivity and specificity for malignancy were 60.0 and 75.0 %, respectively. With 0.0180 %/s or lower slope of washout ratio as a cutoff value, sensitivity and specificity for malignancy were 60.0 and 80.0 %, respectively. CONCLUSIONS: Dynamic contrast-enhanced CT is helpful in differentiating malignant from benign solitary pulmonary nodules. Smaller washout of contrast enhancement is a predictor that a lesion is malignant.
Assuntos
Meios de Contraste , Neoplasias Pulmonares/diagnóstico por imagem , Intensificação de Imagem Radiográfica/métodos , Nódulo Pulmonar Solitário/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Área Sob a Curva , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Curva ROC , Sensibilidade e Especificidade , Adulto JovemRESUMO
The sterol regulatory element binding factor 1 gene (SREBP1) plays an important role in the biosynthesis of fatty acids and cholesterol, and in lipid metabolism. The objective of this study was to investigate the effect of genetic polymorphisms of SREBP1 on the fatty acid composition of muscle and carcass traits in Simmental bulls and Snow Dragon black cattle. The 84-bp insertion/deletion (indel) in intron 5 of the bovine SREBP1 gene was genotyped by polymerase chain reaction to investigate its associations with traits. The results showed that the 84-bp indel in intron 5 was significantly associated with palmitoleic acid (C16:1), stearic acid (C18:0), saturated fatty acids (SFA), triglycerides (TAG), and the C16 index in Simmental bulls (P < 0.05). Cattle with the LL genotype had higher palmitic acid (C16:1), triglycerides, and C16 index but lower stearic acid (C18:0) and SFA compared to those with the LS genotype (P < 0.05). In conclusion, the 84-bp indel of SREBP1 could be used as a genetic marker for selecting Simmental breeding stock for healthier fatty acid composition.
Assuntos
Bovinos/genética , Ácidos Graxos/genética , Carne , Proteína de Ligação a Elemento Regulador de Esterol 1/genética , Animais , Ácidos Graxos/metabolismo , Mutação INDEL , Íntrons , Masculino , Músculo Esquelético/metabolismo , Característica Quantitativa HerdávelRESUMO
Myogenic determination factor 1 (MyoD1) and myogenic factor 6 (Myf6) genes belong to the myogenic differentiation (MyoD) gene family, which play key roles in growth and muscle development. The study aimed to investigate the effects of variants in cattle MyoD1 and Myf6 on carcass and meat traits. We screened single nucleotide polymorphisms (SNPs) of both genes in 8 cattle populations, including Simmental, Angus, Hereford, Charolais, Limousin, Qinchuan, Luxi, and Jinnan by sequencing. The G782A locus was identified in exon 1 of MyoD1 (MyoD1-BglI) as well as the T186C locus in exon 1 of Myf6 (Myf6-ApaLI). For the two SNPs, the A allele was significantly more frequent than the B allele in the populations tested. The χ(2) test showed that the MyoD1-BglI locus conformed to Hardy-Weinberg equilibrium in the 8 populations, as did the Myf6-ApaLI locus, with the exception of the Simmental population (P > 0.05). Association analysis revealed that the MyoD1-BglI locus was significantly associated with loin muscle area (LMA) (P < 0.05), and the Myf6-ApaLI locus was significantly associated with carcass length (CL) (P < 0.05). Animals with BB and AB genotypes for the MyoD1-BglI locus had larger LMAs compared to animals with AA genotype. Individuals with BB genotype had longer CLs compared to those with AA and AB genotypes. We conclude that the two SNPs might provide useful genetic markers, opening up new possibilities for cattle breeding and improvements in gene-assisted selection.
Assuntos
Composição Corporal/genética , Bovinos/genética , Proteína MyoD/genética , Fatores de Regulação Miogênica/genética , Técnicas de Amplificação de Ácido Nucleico/veterinária , Animais , Sequência de Bases , Cruzamento , Bovinos/classificação , Frequência do Gene , Marcadores Genéticos , Carne , Reação em Cadeia da Polimerase/veterinária , Polimorfismo de Fragmento de Restrição , Polimorfismo de Nucleotídeo Único , Locos de Características Quantitativas/genética , Característica Quantitativa Herdável , Seleção Genética , Análise de Sequência de DNA/veterináriaRESUMO
Identification of splice sites plays a key role in the annotation of genes. Consequently, improvement of computational prediction of splice sites would be very useful. We examined the effect of the window size and the number and position of the consensus bases with a chi-square test, and then extracted the sequence multi-scale component features and the position and adjacent position relationship features of consensus sites. Then, we constructed a novel classification model using a support vector machine with the previously selected features and applied it to the Homo sapiens splice site dataset. This method greatly improved cross-validation accuracies for training sets with true and spurious splice sites of both equal and different proportions. This method was also applied to the NN269 dataset for further evaluation and independent testing. The results were superior to those obtained with previous methods, and demonstrate the stability and superiority of this method for prediction of splice sites.
Assuntos
Biologia Computacional/métodos , Sítios de Splice de RNA/genética , Sequência de Bases , Distribuição de Qui-Quadrado , Bases de Dados de Ácidos Nucleicos , Humanos , Curva ROC , Máquina de Vetores de SuporteRESUMO
We examined the spatial and temporal expression of the planarian Dugesia japonica STAG-related gene (DjStag), in both intact and regenerating planarians, by whole-mount in situ hybridization and relative quantitative real-time PCR. The first localized transcripts of DjStag were detected in the blastemas three days after amputation, in all regenerates including those from head, tail and trunk pieces. The maximum level of expression of DjStag transcripts occurred at five days after cutting. After regeneration for seven days, DjStag was weakly expressed. A similar decrease occurs regardless of the orientation of the cut. The expression pattern did not differ significantly in the different types of regeneration. Relative quantitative real-time PCR analysis of DjStag mRNA indicated that the expression of DjStag mRNA was increased after amputation compared to that in normal intact planarians, and the maximum level of expression of DjStag transcripts occurred at five days after amputation. All results suggest that DjStag, implicated in planarian regeneration, plays a role in maintaining the ability of pluripotent stem cells to regenerate lost tissue in planarians.