RESUMO
Bevacizumab has been reported to increase blood pressure. However, the factors, including patient characteristics and laboratory data contributing to this side effect remain unclear. Therefore, we investigated the relationships between increased blood pressure and bevacizumab administration, patient characteristics, and laboratory data. Between April 2007 and January 2018, factor analysis was retrospectively conducted by monitoring increases in blood pressure, the status of bevacizumab administration, patient characteristics, and laboratory data before the first administration in Japanese patients with colorectal cancer who satisfied the criteria for this study. Sixty-seven patients were included, 34 of whom (50.7%) had an increase in blood pressure after bevacizumab administration. On univariate analysis, liver metastasis, antihypertensive drug use, systolic blood pressure at rest before the first bevacizumab administration, body mass index, creatinine, and blood platelet count were significantly different between the two groups. Multivariate analysis was conducted using increased blood pressure as an objective variable and the factors extracted by the univariate analysis as explanatory variables. The results suggested that liver metastasis, antihypertensive drugs, systolic blood pressure at rest before the first bevacizumab administration, and creatinine were associated with the increase in blood pressure. Furthermore, a log-rank test performed based on Kaplan-Meier curves demonstrated that liver metastasis in patients not taking antihypertensive drugs and antihypertensive drug use in patients without liver metastasis were significantly associated with increased blood pressure. Additionally, liver metastasis in patients with antihypertensive drug use was significantly associated with increased blood pressure. Our findings suggest that liver metastasis and antihypertensive drug use, which was previously reported, are risk factors for increased blood pressure.
Assuntos
Antineoplásicos Imunológicos/administração & dosagem , Bevacizumab/administração & dosagem , Pressão Sanguínea/efeitos dos fármacos , Neoplasias Colorretais/tratamento farmacológico , Idoso , Anti-Hipertensivos/uso terapêutico , Antineoplásicos Imunológicos/efeitos adversos , Povo Asiático , Bevacizumab/efeitos adversos , Pressão Sanguínea/fisiologia , Análise Fatorial , Feminino , Humanos , Hipertensão/epidemiologia , Hipertensão/etiologia , Estimativa de Kaplan-Meier , Neoplasias Hepáticas/secundário , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Estudos Retrospectivos , Fatores de RiscoAssuntos
Densidade Óssea/efeitos dos fármacos , Glucocorticoides/uso terapêutico , Síndrome Nefrótica/metabolismo , Adolescente , Adulto , Criança , Pré-Escolar , Progressão da Doença , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Síndrome Nefrótica/tratamento farmacológico , RecidivaRESUMO
AIM: There are conflicting data regarding the clinical benefit of the effect of HMG-CoA reductase inhibitors (statins) in osteoporosis. We have reported that fluvastatin (a statin) is effective in improving proteinuria and renal function in childhood IgA nephropathy with mild histological findings and moderate proteinuria. The aim of the present study was to clarify the effect of fluvastatin on the bone mineral density, bone metabolic markers, proteinuria, and renal function of children with minimal change glomerulonephritis with some focal mesangial cell proliferation whose glomeruli did not stain positive for IgA and on moderate proteinuria. PATIENTS AND METHODS: We conducted a prospective controlled study of 36 children who had recently been diagnosed with normocholesterolemic minimal change glomerulonephritis with some focal mesangial cell proliferation and moderate proteinuria, and in whom strenuous exercise was restricted. The 36 patients were randomly assigned to receive 20 mg of fluvastatin (group 1) or 5 mg/kg of dipyridamole (group 2) for two years. RESULTS: By the end of the trial, there was no difference in BMD between the groups, and there were no changes in the four bone metabolic parameters. However, the urinary protein, hematuria and BUN levels had significantly decreased in group 1 compared to baseline, and the serum total protein and albumin levels and creatinine clearance had significantly increased in group 1 compared to baseline and group 2. CONCLUSIONS: The results of this study suggest that fluvastatin therapy has an antiproteinuric effect and improves renal function in moderately proteinuric patients with mild histological glomerulonephritis, but does not increase BMD.
Assuntos
Densidade Óssea/efeitos dos fármacos , Ácidos Graxos Monoinsaturados/farmacologia , Inibidores de Hidroximetilglutaril-CoA Redutases/farmacologia , Indóis/farmacologia , Nefrite/metabolismo , Nefrose Lipoide/metabolismo , Fosfatase Ácida/sangue , Fosfatase Ácida/efeitos dos fármacos , Adolescente , Adulto , Fosfatase Alcalina/sangue , Fosfatase Alcalina/efeitos dos fármacos , Aminoácidos/efeitos dos fármacos , Aminoácidos/urina , Criança , Ácidos Graxos Monoinsaturados/uso terapêutico , Feminino , Fluvastatina , Humanos , Inibidores de Hidroximetilglutaril-CoA Redutases/uso terapêutico , Indóis/uso terapêutico , Isoenzimas/sangue , Isoenzimas/efeitos dos fármacos , Masculino , Nefrite/complicações , Nefrite/tratamento farmacológico , Nefrose Lipoide/complicações , Nefrose Lipoide/tratamento farmacológico , Osteocalcina/sangue , Osteocalcina/efeitos dos fármacos , Estudos Prospectivos , Fosfatase Ácida Resistente a TartaratoRESUMO
AIM: In recent reports, some kinds of HMG-CoA reductase inhibitors were able to decrease proteinuria and to improve renal function. Here we aimed to clarify the effect of fluvastatin (an HMG-CoA reductase inhibitor) on proteinuria and renal function in children with mild IgA nephropathy. PATIENTS AND METHODS: We conducted a prospective controlled study of 30 children who had been recently diagnosed with normocholesterolemic IgA nephropathy following the detection of a minor lesion or of focal mesangial proliferation and moderate proteinuria. The 30 patients were randomly assigned to receive both of 20 mg of fluvastatin and 5 mg/kg of dipyridamole (group 1), or 5 mg/kg of dipyridamole only (group 2) for 1 year. RESULTS: By the end of the trial, urinary protein, hematuria, BUN and serum creatinine levels had significantly decreased in the patients of group 1 as compared to baseline. Serum total cholesterol, triglyceride and LDL cholesterol levels had significantly decreased, while serum total protein and albumin, and creatinine clearance had significantly increased in group 1 as compared to baseline and group 2. The urinary protein level had significantly decreased in the group 2 patients as compared to baseline, but only slightly. CONCLUSIONS: The results of this study suggest that fluvastatin and dipyridamole treatment yields an antiproteinuric effect and leads to the amelioration of renal function in moderately proteinuric patients with mild histological IgA nephropathy.
Assuntos
Dipiridamol/administração & dosagem , Ácidos Graxos Monoinsaturados/administração & dosagem , Glomerulonefrite por IGA/tratamento farmacológico , Inibidores de Hidroximetilglutaril-CoA Redutases/administração & dosagem , Indóis/administração & dosagem , Proteinúria/tratamento farmacológico , Vasodilatadores/administração & dosagem , Adolescente , Criança , Quimioterapia Combinada , Feminino , Fluvastatina , Glomerulonefrite por IGA/complicações , Glomerulonefrite por IGA/patologia , Humanos , Rim/efeitos dos fármacos , Rim/patologia , Rim/fisiopatologia , Masculino , Estudos Prospectivos , Proteinúria/etiologia , Proteinúria/patologiaRESUMO
To clarify the longitudinal metabolic process of bone growth in children, we observed the relationship between the level of serum osteocalcin (OC), a marker of bone metabolism, and growth velocity in 10 prepubertal patients with congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency and 9 prepubertal patients with nonendocrine short stature (NESS), but no major hormonal abnormalities influencing bone metabolism. Observations were made every 6 months over a 7-year period. In patients with CAH who exhibited a wide variation in growth velocity during the course of the investigation, the levels of OC fluctuated over a wide range, suggesting metabolically variable bone growth. In contrast, in patients with NESS who exhibited a relatively stable growth velocity, the OC level remained within a narrow range, suggesting metabolically stable bone growth. The meaning of such divergent metabolic processes of bone growth observed in CAH and NESS and its relationship to actual bone structure or bone intensity should be further investigated.
Assuntos
Hiperplasia Suprarrenal Congênita/fisiopatologia , Desenvolvimento Ósseo , Transtornos do Crescimento/fisiopatologia , Adolescente , Hiperplasia Suprarrenal Congênita/sangue , Hiperplasia Suprarrenal Congênita/enzimologia , Criança , Pré-Escolar , Feminino , Transtornos do Crescimento/sangue , Transtornos do Crescimento/etiologia , Humanos , Masculino , Osteocalcina/sangue , Estudos Prospectivos , Esteroide 21-Hidroxilase/metabolismoRESUMO
One of the many intriguing features of gene silencing by RNA interference is the apparent catalytic nature of the phenomenon. New biochemical and genetic evidence now shows that an RNA-directed RNA polymerase chain reaction, primed by siRNA, amplifies the interference caused by a small amount of "trigger" dsRNA.
Assuntos
Inativação Gênica/fisiologia , RNA Mensageiro/antagonistas & inibidores , RNA não Traduzido/fisiologia , RNA Polimerase Dependente de RNA/fisiologia , Animais , Sistema Livre de Células , Drosophila melanogaster/embriologia , Drosophila melanogaster/genética , Endorribonucleases/fisiologia , Marcação de Genes , Proteínas de Insetos/fisiologia , Modelos Genéticos , Proteínas de Plantas/fisiologia , Reação em Cadeia da Polimerase/métodos , Processamento Pós-Transcricional do RNA , RNA de Cadeia Dupla/farmacologia , RNA de Cadeia Dupla/fisiologia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA Interferente Pequeno , RNA não Traduzido/genética , Ribonuclease III , Homologia de Sequência do Ácido NucleicoRESUMO
BACKGROUND: The superficial spreading type of gastric carcinoma may originate from either a single cellular clone or from several different clones; this issue remains controversial. Indeed, the p53 gene has been shown to play an important role in gastric carcinogenesis, but there have been only a few reports on the heterogeneity of gastric carcinoma with respect to the p53 gene. METHODS: We analyzed seven cases of the superficial spreading type of gastric submucosal carcinomas (80 lesions; 10 to 17 per case) which showed different histological types and/or different p53 protein staining patterns. Direct sequences of polymerase chain reaction products were used for the analysis. RESULTS: p53 Gene heterogeneity in mucosal carcinoma lesions was detected in three cases. However, in all of the cases, the p53 mutational pattern was identical to that found in the submucosal carcinoma lesions. In the heterogeneous cases, the mutation in the submucosal carcinoma was one of the mutation patterns found among the mucosal carcinoma lesions. More precisely, the mutational pattern of both submucosal carcinoma lesions and the mucosal lesions located just above them, was identical. CONCLUSION: These data suggest that, with regard to the p53 gene, in some superficial spreading types of gastric carcinomas, there are various subclones in the mucosal carcinoma; one of these subclones becomes predominant through clonal selection, and, thus, invades the submucosa.
Assuntos
Genes p53 , Mutação/genética , Neoplasias Gástricas/genética , Idoso , Idoso de 80 Anos ou mais , Feminino , Heterogeneidade Genética , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias Gástricas/patologiaRESUMO
Multiple members of the ADAR (adenosine deaminases acting on RNA) gene family are involved in A-to-I RNA editing. It has been speculated that they may form a large multicomponent protein complex. Possible candidates for such complexes are large nuclear ribonucleoprotein (lnRNP) particles. The lnRNP particles consist mainly of four spliceosomal subunits that assemble together with the pre-mRNA to form a large particle and thus are viewed as the naturally assembled pre-mRNA processing machinery. Here we investigated the presence of ADARs in lnRNP particles by Western blot analysis using anti-ADAR antibodies and by indirect immunoprecipitation. Both ADAR1 and ADAR2 were found associated with the spliceosomal components Sm and SR proteins within the lnRNP particles. The two ADARs, associated with lnRNP particles, were enzymatically active in site-selective A-to-I RNA editing. We demonstrate the association of ADAR RNA editing enzymes with physiological supramolecular complexes, the lnRNP particles.
Assuntos
Adenosina Desaminase/fisiologia , Núcleo Celular/metabolismo , Edição de RNA , Precursores de RNA/metabolismo , Ribonucleoproteínas/análise , Adenosina Desaminase/análise , Humanos , Splicing de RNA , Proteínas de Ligação a RNARESUMO
To clarify the independent physiological roles of adrenal androgen and estrogen on bone growth, we compared the lumbar spine bone mineral density (BMD) in prepubertal girls with virilizing congenital adrenal hyperplasia (CAH) (n = 17) and girls with central precocious puberty (CPP) (n = 18). When BMD was analyzed according to chronologic age, no significant differences were found between CPP and CAH patients. However, when adjusted to bone age, BMD was statistically higher in CAH than in CPP subjects. This finding suggests that adrenal androgen, as well as estrogen, plays an important role in increasing BMD. Adrenal androgen may act on bone not only as androgen, but as estrogen after having been metabolized into an aromatized bone-active compound in peripheral tissues, such as bone and fat. Therefore, adrenal androgen may have a more important role in increasing BMD than previously realized.
Assuntos
Glândulas Suprarrenais/fisiologia , Androgênios/fisiologia , Densidade Óssea/fisiologia , Desenvolvimento Ósseo/fisiologia , Estrogênios/fisiologia , Absorciometria de Fóton , Hiperplasia Suprarrenal Congênita/metabolismo , Hiperplasia Suprarrenal Congênita/fisiopatologia , Determinação da Idade pelo Esqueleto , Criança , Feminino , Humanos , Puberdade Precoce/metabolismo , Puberdade Precoce/fisiopatologiaRESUMO
OBJECTIVES: To elucidate the metabolic effects of topical testosterone for the treatment of microphallus in children. METHODS: We administered 5% testosterone ointment to 50 prepubertal boys for the treatment of microphallus, allowing us to observe its metabolic effect on plasma concentrations of testosterone as a marker of transdermally absorbed testosterone, insulin-like growth factor (IGF)-I as a marker of growth hormone secretion status, and osteocalcin as a marker of bone metabolic turnover. RESULTS: Transdermal application of testosterone for 30 days at a dose that affects penile growth increased mean (+/-SD) plasma testosterone concentrations from 7.5+/-5.1 to 31.0+/-8.2 ng/dL (pre- vs. post-treatment, respectively; P<0.01). This was associated with a slight but statistically significant elevation of IGF-I concentrations (117.2+/-76.9 vs. 154.4+/-81.5 ng/mL; P<0.05). No significant change in osteocalcin levels was found. CONCLUSIONS: When using testosterone ointment as a treatment for microphallus, it should be borne in mind that this application has systemic effects.
Assuntos
Osso e Ossos/metabolismo , Hipogonadismo/tratamento farmacológico , Fator de Crescimento Insulin-Like I/metabolismo , Testosterona/farmacologia , Testosterona/uso terapêutico , Administração Cutânea , Biomarcadores/sangue , Criança , Pré-Escolar , Humanos , Hipogonadismo/metabolismo , Lactente , Masculino , Osteocalcina/sangue , Testosterona/administração & dosagemAssuntos
Estatura/efeitos dos fármacos , Ciclosporina/administração & dosagem , Síndrome Nefrótica/tratamento farmacológico , Estatura/fisiologia , Criança , Transtornos do Crescimento/induzido quimicamente , Transtornos do Crescimento/prevenção & controle , Humanos , Masculino , Síndrome Nefrótica/induzido quimicamente , Prednisolona , Esteroides/efeitos adversosRESUMO
The aim of this study was to elucidate whether or not p53 genetic heterogeneity would occur while colorectal carcinoma was limited to the mucosa. Eight cases of endoscopically resected colorectal intramucosal carcinomas were analyzed to determine the p53 gene sequence (exons 5 to 8). Six out of 8 cases showed p53 gene mutations, and in all of them, the mutational status was heterogeneous. In 4 cases, mutated codons were heterogeneous as well. These data indicate that p53 gene alterations in colorectal carcinomas occur and diverge at the stage of intramucosal carcinoma, supporting our previously proposed hypothesis that colorectal carcinomas can be composed of various subclones as regards p53 gene mutation, while the carcinoma is limited to the mucosa, and one of these subclones commences invasion to the submucosa after clonal selection, thus generating a monoclonal invasive carcinoma.
Assuntos
Carcinoma/genética , Neoplasias Colorretais/genética , Genes p53 , Mutação , Carcinoma/metabolismo , Neoplasias Colorretais/metabolismo , Análise Mutacional de DNA , DNA de Neoplasias/análise , Variação Genética , Humanos , Mucosa Intestinal , Proteína Supressora de Tumor p53/metabolismoRESUMO
The members of the ADAR (adenosine deaminase acting on RNA) gene family are involved in site-selective RNA editing that changes adenosine residues of target substrate RNAs to inosine. Analysis of staged chimeric mouse embryos with a high contribution from embryonic stem cells with a functional null allele for ADAR1 revealed a heterozygous embryonic-lethal phenotype. Most ADAR1+/- chimeric embryos died before embryonic day 14 with defects in the hematopoietic system. Our results suggest the importance of regulated levels of ADAR1 expression, which is critical for embryonic erythropoiesis in the liver.
Assuntos
Adenosina Desaminase/genética , Eritropoese , Células-Tronco Hematopoéticas/citologia , Fígado/embriologia , Edição de RNA , Adenosina Desaminase/metabolismo , Alelos , Animais , Quimera , Desenvolvimento Embrionário e Fetal , Eritroblastos/citologia , Feminino , Células-Tronco Hematopoéticas/enzimologia , Hepatócitos/citologia , Técnicas Imunoenzimáticas , Fígado/citologia , Fígado/enzimologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos SCID , Fenótipo , Proteínas de Ligação a RNA , Células-Tronco/citologia , Células-Tronco/enzimologia , Teratoma/genética , Teratoma/patologiaRESUMO
The incidence and histopathologic characteristics of nonpolypoid (superficial type) early colorectal carcinomas were studied and compared with those of the polypoid type. The superficial type was subclassified as elevated (type IIa), type IIa with central depression (type IIa + IIc), plain (type IIb), depressed (type IIc), and IIc with marginal elevation (type IIc + IIa). The superficial type comprised 22% and 27% of intramucosal and submucosal carcinomas, respectively. Pure type IIb was not found, and there were only three pure type IIc lesions. Type IIa + IIc and IIc + IIa (and IIc) showed a significantly higher rate of submucosal invasion among the small tumors (59% and 71% less than 20 mm, respectively) compared to the polypoid type; type IIa showed no significant difference. The incidence of lymph node metastasis among submucosal carcinomas showed no significant difference between the superficial type and the polypoid type. About 64% and 52% of type IIa and IIa + IIc tumors accompanied residual adenoma, suggesting that they originated from small, flat adenomas through the adenoma-carcinoma sequence, whereas type IIc + IIa (and IIc) did not have an adenomatous component, implying that they arose de novo or originated through an adenoma-carcinoma sequence at a smaller size than the type IIa and IIa + IIc lesions. Superficial-type early colorectal carcinomas are not rare, and they are not uniform in nature. Rapid growth and invasion to the submucosa is characteristic of superficial-type lesions with a central depression, and only superficial depressed (type IIc + IIa, IIc) lesions can arise de novo. Although they grow rapidly to invade the submucosa, it cannot be said that they show more aggressive behavior than the polypoid type.
Assuntos
Adenocarcinoma/patologia , Pólipos do Colo/patologia , Neoplasias Colorretais/patologia , Humanos , Metástase Linfática , Invasividade NeoplásicaRESUMO
AIMS: Recent studies suggest that primary low-grade gastric lymphomas of mucosa-associated lymphoid tissue (MALT) are cured in many cases between 1 and 18 months after H. pylori eradication. The aim of this study is to elucidate when complete regression (CR) of MALT lymphoma can be histologically predicted after H. pylori eradication. METHODS AND RESULTS: Twenty-one patients with low-grade gastric MALT lymphoma were treated with triple therapy (amoxicillin, clarythromycin and proton pump inhibitor) for 14 days. Subsequently, they were followed up by sequential endoscopy and biopsy (number of biopsy specimens for each endoscopy is 3-8, with an average of 4) from 91 to 657 days (average: 309 +/- 165 days). Eradication of H. pylori infection was achieved in all patients. Nine patients were free of lymphoma at 1 to 2 months after eradication and remained in CR at 163-657 days. Twelve patients showed residual lymphoma at 1 to 2 months after eradication. Five out of 12 patients revealed only one or two small foci of lymphoma-cell aggregation and showed a high incidence (80%) of CR at the latest biopsy (135-434 days, average 276 +/- 115 days after eradication), while seven patients showed diffuse remains of lymphoma cells and indicated CR in only one case (14%) at 362 days, partial regression in five cases at 130-431 days (average 227 +/- 114 days), and no change in one case at 91 days after eradication. CONCLUSIONS: : These results suggest that CR of low-grade MALT lymphoma can be predicted at 1 to 2 months after eradication therapy by checking histological changes of MALT lymphoma cells.
Assuntos
Infecções por Helicobacter/microbiologia , Helicobacter pylori , Linfoma de Zona Marginal Tipo Células B/patologia , Neoplasias Gástricas/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Amoxicilina/uso terapêutico , Biópsia , Claritromicina/uso terapêutico , Feminino , Seguimentos , Gastroscopia , Infecções por Helicobacter/tratamento farmacológico , Infecções por Helicobacter/patologia , Helicobacter pylori/efeitos dos fármacos , Humanos , Linfoma de Zona Marginal Tipo Células B/tratamento farmacológico , Linfoma não Hodgkin/tratamento farmacológico , Linfoma não Hodgkin/patologia , Masculino , Pessoa de Meia-Idade , Inibidores da Bomba de Prótons , Indução de Remissão , Estômago/efeitos dos fármacos , Estômago/microbiologia , Estômago/patologia , Neoplasias Gástricas/tratamento farmacológico , Neoplasias Gástricas/microbiologia , Fatores de TempoRESUMO
Clinically, differential diagnosis of pancreatic carcinoma (PC) and so-called "mass-forming pancreatitis (MFP)" is difficult. We analyzed the amount, ductal level, and K-ras mutation of ductal hyperplasia and intraductal carcinoma in surgically resected cases of MFP (n = 18) and PC (n = 16). DNAs extracted from microdissected epithelial foci were analyzed for K-ras codon 12 mutation by nested polymerase chain reaction and restriction fragment length polymorphism. The histology of MFP showed severe destruction of exocrine tissue and pancreatic stones and/or protein plugs (72%, 13 of 18 cases) in mostly peripheral ducts. The average basal membrane lengths of nonpapillary and papillary hyperplasia in cases of carcinoma were about 4 and 15 times more than those of MFP, respectively. The frequency of K-ras mutation in hyperplastic foci increased from nonpapillary [six (27%) of 22] to papillary foci [16 (64%) of 25] in K-ras mutant PCs, but there was no difference between nonpapillary [one (6%) of 18] and papillary foci (none of 19) in K-ras wild-type PCs, and also between nonpapillary (none of 24) and papillary foci [one (7%) of 14] in MFPs.
Assuntos
Adenocarcinoma/genética , Carcinoma Ductal Pancreático/genética , Genes ras , Mutação , Neoplasias Pancreáticas/genética , Pancreatite/genética , Adenocarcinoma/patologia , Adenocarcinoma/cirurgia , Adulto , Idoso , Carcinoma Ductal Pancreático/patologia , Carcinoma Ductal Pancreático/cirurgia , Membrana Celular/patologia , Doença Crônica , Códon , Células Epiteliais/metabolismo , Células Epiteliais/patologia , Feminino , Humanos , Hiperplasia , Masculino , Pessoa de Meia-Idade , Ductos Pancreáticos/metabolismo , Ductos Pancreáticos/patologia , Neoplasias Pancreáticas/patologia , Neoplasias Pancreáticas/cirurgia , Pancreatite/patologia , Pancreatite/cirurgia , Estudos RetrospectivosRESUMO
Members of the double-stranded RNA- (dsRNA) specific adenosine deaminase gene family convert adenosine residues into inosines in dsRNA and are involved in A-to-I RNA editing of transcripts of glutamate receptor (GluR) subunits and serotonin receptor subtype 2C (5-HT(2C)R). We have isolated hADAR3, the third member of this class of human enzyme and investigated its editing site selectivity using in vitro RNA editing assay systems. As originally reported for rat ADAR3 or RED2, purified ADAR3 proteins could not edit GluR-B RNA at the "Q/R" site, the "R/G" site, and the intronic "hot spot" site. In addition, ADAR3 did not edit any of five sites discovered recently within the intracellular loop II region of 5-HT(2C)R RNAs, confirming its total lack of editing activity for currently known substrate RNAs. Filter-binding analyses revealed that ADAR3 is capable of binding not only to dsRNA but also to single-stranded RNA (ssRNA). Deletion mutagenesis identified a region rich in arginine residues located in the N-terminus that is responsible for binding of ADAR3 to ssRNA. The presence of this ssRNA-binding domain as well as its expression in restricted brain regions and postmitotic neurons make ADAR3 distinct from the other two ADAR gene family members, editing competent ADAR1 and ADAR2. ADAR3 inhibited in vitro the activities of RNA editing enzymes of the ADAR gene family, raising the possibility of a regulatory role in RNA editing.
Assuntos
Adenosina Desaminase/genética , Adenosina Desaminase/metabolismo , Família Multigênica , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Adenosina Desaminase/química , Sequência de Aminoácidos , Animais , Sequência de Bases , Sítios de Ligação/genética , Encéfalo/metabolismo , Primers do DNA/genética , DNA Complementar/genética , DNA Complementar/isolamento & purificação , Expressão Gênica , Humanos , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Estrutura Terciária de Proteína , Edição de RNA , RNA de Cadeia Dupla/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteínas de Ligação a RNA/química , Ratos , Homologia de Sequência de Aminoácidos , Distribuição TecidualRESUMO
Different isoforms of serotonin subtype 2C receptor (5-HT(2C)R) with altered G protein-coupling efficacy are generated by RNA editing, which converts genomically encoded adenosine residues into inosines. In combination, editing of five sites all located within the second intracellular loop region of 5-HT(2C)R mRNA changes the gene-encoded Ile, Asn, and Ile at positions 156, 158, and 160, respectively. We analyzed the G protein-coupling functions of previously unreported editing isoform receptors. An approximately 13-fold reduction in the agonist potency for G protein-coupling stimulation as well as a significantly reduced basal level activity was observed with the thalamus-specific isoform carrying Ile156, Gly158, and Val160 (5-HT(2C)R-IGV). In contrast, the agonist was four- to five-fold less potent with 5-HT(2C)R-MSV and -IDV, detected in the amygdala and choroid plexus, respectively, indicating a dominant role for the amino acid residue at position 158 in receptor functions. We also identified a splicing variant receptor with a truncated C terminus that displayed no ligand binding capacity or G protein-coupling activity. Examination of the alternatively spliced RNA encoding this truncated receptor suggests that editing of this variant RNA occurs after completion of splicing, resulting in complete editing at all five sites.
Assuntos
Proteínas de Ligação ao GTP/metabolismo , Edição de RNA , Receptores de Serotonina/genética , Receptores de Serotonina/metabolismo , Células 3T3 , Processamento Alternativo , Sequência de Aminoácidos/genética , Animais , Sequência de Bases/genética , Encéfalo/metabolismo , Humanos , Camundongos , Dados de Sequência Molecular , Fragmentos de Peptídeos/genética , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , RNA/metabolismo , Splicing de RNA , Receptor 5-HT2C de Serotonina , Distribuição TecidualRESUMO
Mucous cell hyperplasia (MCH) has been considered an important precursor of pancreatic ductal carcinoma based on histological and molecular research, although various K-ras mutations rates are seen among cases with pancreatic carcinoma, chronic pancreatitis and normal pancreas, with a wide range of histological characters. To investigate the premalignant potential of MCH and the multicentricity of pancreatic carcinoma, we analyzed K-ras mutation at codon 12 in carcinoma foci of 82 cases of surgically-resected pancreatic carcinoma [67 solid-type carcinomas (SCs) and 15 ductectatic-type carcinomas (DCs)], as well as in both MCH and carcinoma foci in 42 cases (30 SCs and 12 DCs), using an enriched polymerase chain reaction (PCR)-enzyme linked mini-sequence assay (ELMA). K-ras mutation was recognized in 85% (57/67) of SCs and 73% (11/15) of DCs, and multiple K-ras mutations in 12% (8/67) of SCs and in 20% (3/15) of DCs. Multiple K-ras mutations were also recognized in MCHs in 47% (14/30) of SCs and in 42% (5/12) of DCs. Moreover, the same sequence at K-ras codon 12 in MCH and carcinoma was identified in 76% (32/42) of carcinoma cases and it was more frequently recognized in hyperplasias with histological atypia (51%, 37 of 72 foci) than those without atypia (24%, 16 of 68 foci) (P<0.0007). These results further support the idea of multicentric carcinogenesis and premalignant potential of atypical hyperplasia in the human pancreas, although about half of the hyperplasias around carcinomas were not thought to be direct precursors.