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1.
Clin Oncol (R Coll Radiol) ; 35(10): 652-664, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37541936

RESUMO

Surgical resection, stereotactic body radiotherapy (SBRT) and radiofrequency ablation (RFA) have seldom been compared for small hepatocellular carcinoma (HCC). We explored the treatment outcomes of SBRT for small HCC by conducting a network meta-analysis (NMA). We compared the efficacy and safety of surgical resection, RFA and SBRT for liver-confined small HCC (three or fewer lesions with a diameter ≤5 cm). The study endpoint included the odds ratios of the 1-, 3- and 5-year progression/recurrence/disease-free survival (disease progression-free survival; DPFS) and overall survival rates, as well as severe complications. Forty-five studies included 21 468 patients. In the NMA with comparable data, SBRT had comparable 1-, 3- and 5-year DPFS but significantly worse pooled long-term overall survival (3- and 5-year overall survival) than surgical resection (odds ratio 1.39, 95% confidential interval 1.3-1.89; odds ratio 1.33, 95% confidence interval 1.06-1.69, respectively). SBRT was associated with significantly better pooled 1-year DPFS compared with RFA (odds ratio 0.39, 95% confidence interval 0.15-0.97), with the remaining outcomes being comparable. SBRT had significantly less incidence of severe complications compared with surgical resection (odds ratio 0.62, 95% confidence interval 0.42-0.88) and RFA (odds ratio 0.2, 95% confidence interval 0.03-0.94). In conclusion, for small HCCs (≤5 cm) with one to three nodules, SBRT may be favourable to reduce the risks of severe complications. In terms of DPFS, SBRT may be recommended as an alternative first-line therapy for RFA and surgical resection. The results regarding overall survival should be interpreted with caution, considering the potentially uneliminated bias. There is a clear need for well-designed randomised trials to conclusively identify real differences in efficacy between these treatments, especially SBRT and surgical resection.


Assuntos
Carcinoma Hepatocelular , Ablação por Cateter , Neoplasias Hepáticas , Radiocirurgia , Humanos , Carcinoma Hepatocelular/radioterapia , Carcinoma Hepatocelular/cirurgia , Carcinoma Hepatocelular/patologia , Neoplasias Hepáticas/radioterapia , Neoplasias Hepáticas/cirurgia , Neoplasias Hepáticas/patologia , Radiocirurgia/métodos , Metanálise em Rede , Ablação por Cateter/métodos , Resultado do Tratamento
2.
J Clin Invest ; 70(6): 1334-9, 1982 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-7174798

RESUMO

We have analyzed cultured skin fibroblasts derived from patients with argininosuccinate synthetase deficiency for alterations in gene structure, mRNA content, and protein structure. Genomic DNA was digested with the endonucleases EcoRI or HindIII, and the fragments were analyzed by Southern blotting and hybridization with a cDNA probe for argininosuccinate synthetase. The blot pattern is complex because there are at least 10 copies of argininosuccinate synthetase-like genes scattered over multiple human chromosomes. All nine patients studied showed patterns of DNA fragments that were indistinguishable from the normal control cell lines, and despite the possibility that the complexity could mask some changes, major deletions of the active gene(s) were not present. Blot hybridization of RNA indicated the presence of hybridizable mRNA of approximately normal size in seven of seven individuals examined with a suggestion of some heterogeneity. Analysis of enzyme antigen by protein transfer from NaDodSO4 containing polyacrylamide gels revealed considerable heterogeneity. This analysis revealed no cross-reacting material (CRM) in nine cell lines, CRM of normal molecular weight in one cell line, and CRM of reduced molecular weight in one cell line. These findings suggest that the genes for argininosuccinate synthetase in most citrullinemia patients are transcribed and produce stable mRNA. These mRNA either are not translated, or the translation product (enzyme) is rapidly degraded or is immunologically nonreactive. Defective gene expression in this disorder appears to involve abnormal mRNA, which may be altered by point mutations, frame shift mutations, deletions, insertions or particularly by abnormal RNA processing.


Assuntos
Argininossuccinato Sintase/deficiência , Ligases/deficiência , Argininossuccinato Sintase/genética , Argininossuccinato Sintase/metabolismo , Células Cultivadas , Citrulina/metabolismo , DNA/genética , Fibroblastos/enzimologia , Heterozigoto , Humanos , Mutação , Polimorfismo Genético , RNA Mensageiro/genética
3.
J Clin Invest ; 83(2): 421-9, 1989 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-2536398

RESUMO

Previous reports indicate that human hepatocytes do not express class I and class II MHC antigens. Our analyses on 10 human hepatocellular carcinoma (HCC) cell lines by immunofluorescence tests and RIA, demonstrate that all the human HCC cell lines tested express class I MHC antigens and among them, three poorly differentiated human HCC cell lines also express class II MHC antigens. Results of immunoprecipitation and/or Western blotting experiments indicate similarity in the chemical nature of both the class I and class II MHC antigens expressed by the human HCC cell lines and by a human B lymphoblastoid cell line Raji. Furthermore, a new variant form of class I antigen was detected in some of these HCC cell lines. Immunohistochemical studies of HCC tissues using the peroxidase-antiperoxidase staining method indicated that class I and class II antigens were detectable in 7 out of 11 and 3 out of 11 HCC tissues from patients, respectively. The availability of MHC class I antigen-positive cultured HCC cell lines, including the poorly differentiated lines that also express MHC class II antigen, has provided us with interesting models to study the relationship between expression of MHC antigen and transformation and differentiation of human hepatocytes. These studies will also allow us some insight into the role of MHC class I and class II antigen in the immunosensitivity and immunogenicity of HCC cells to the host-immune response.


Assuntos
Carcinoma Hepatocelular/metabolismo , Antígenos de Histocompatibilidade Classe II/biossíntese , Antígenos de Histocompatibilidade Classe I/biossíntese , Neoplasias Hepáticas/metabolismo , Western Blotting , Linhagem Celular , Eletroforese em Gel de Poliacrilamida , Imunofluorescência , Humanos , Radioimunoensaio , Tunicamicina/farmacologia
4.
J Clin Invest ; 79(1): 175-8, 1987 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-2878937

RESUMO

The effects of somatostatin (SRIF), insulin, and triiodothyronine (T3) on the growth of human hepatoma cells were investigated on the well-differentiated human hepatoma cell line Hep3B. Results showed that both insulin and T3 can stimulate cell growth of serum starved Hep3B cells at physiological concentrations. SRIF alone showed little growth-promoting activity. When added concurrently with insulin, however, SRIF suppressed the insulin-induced cell proliferation in a dose-dependent manner. On the other hand, SRIF had no inhibitory effect on T3-induced cell proliferation. SRIF is labile in the medium, with a half-life of about 2 h during culture incubation. SRIF did not disturb the insulin binding to its surface receptors nor inhibit the insulin-dependent receptor kinase activity of Hep3B cells in vitro. These results suggest that postreceptor regulation may be involved. The selective suppression by SRIF of insulin-induced cell growth provides an unique approach to the study of insulin actions on proliferation of human hepatoma cells.


Assuntos
Divisão Celular/efeitos dos fármacos , Insulina/farmacologia , Fígado/citologia , Somatostatina/farmacologia , Carcinoma Hepatocelular/patologia , Linhagem Celular , Relação Dose-Resposta a Droga , Humanos , Insulina/metabolismo , Antagonistas da Insulina , Neoplasias Hepáticas , Fosforilação , Receptor de Insulina/metabolismo , Fatores de Tempo , Tri-Iodotironina/farmacologia
5.
Cancer Res ; 49(7): 1773-7, 1989 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-2466561

RESUMO

Using complementary DNAs of human insulin-like growth factors as probes, expressions of the insulin-like growth factors I and II mRNA were examined in seven human hepatoma tissues and their adjacent nontumorous livers. The level of insulin-like growth factor I mRNA in hepatoma was lower than that in the nontumorous liver control. This phenomenon was probably caused by the low expression of human growth hormone receptor in hepatoma tissues. The levels of insulin-like growth factor II mRNA vary among hepatomas. Some show elevated expression; some have diminished expression compared to their nontumorous liver counterparts. In four of the seven hepatomas, expression of fetal forms of insulin-like growth factor II transcripts was observed and may represent dedifferentiation of insulin-like growth factor II expression during hepatocarcinogenesis.


Assuntos
Carcinoma Hepatocelular/metabolismo , Fator de Crescimento Insulin-Like II/genética , Fator de Crescimento Insulin-Like I/genética , Neoplasias Hepáticas/metabolismo , Somatomedinas/genética , Transcrição Gênica , Humanos , RNA Mensageiro/análise , Receptores da Somatotropina/genética , alfa-Fetoproteínas/genética
6.
Exp Hematol ; 24(3): 437-44, 1996 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-8599973

RESUMO

A panel of two poorly differentiated (HA22T/VGH and SK-Hep-1) and six well-differentiated (HuH-6-cl 5, HuH-7, PLC/PRF/5, Hep G2, Hep 3B, and Tong) human hepatocellular carcinoma (HCC) cell lines were studied for the production of colony-stimulating factors (CSFs) using the granulocyte and macrophage colony formation (CFU-GM) assay, immunocytochemical staining, and Northern blotting. Medium conditioned by untreated HA22T/VGH cells contained a high level of CSFs that could stimulate the in vitro colony formation of human myeloid progenitor cells. The HA22T/VGH cell-derived CSF had an apparent molecular weight of 23 kD. Its activity could be effectively neutralized by antiserum against granulocyte-macrophage CSF (GM-CSF) but not by antibodies to other hematopoietic growth factors, including G-CSF, M-CSF, interleukin-3 (IL-3), and IL-6. Correspondingly, immunocytochemical studies using monoclonal anti-GM-CSF showed a strong positive reaction in the cytoplasm of the HA22T/VGH cells. Northern blot analysis revealed that untreated HA22T/VGH cells expressed a considerable amount of GM-CSF mRNA, confirming that GM-CSF production was constitutive. At optimal concentrations, lipopolysaccharide (LPS), IL-1beta, interferon-gamma (IFN-gamma), and tumor-promoting phorbol diester (TPA) could all stimulate HA22T/VGH cells to secrete GM-CSF. In addition to HA22T/VGH, SK-Hep-1 cells could also produce GM-CSF, although less effectively, whereas all the well-differentiated HCC cell lines tested were negative for CSF production. Morphologic, cytochemical, and immunocytochemical examinations demonstrated that both poorly differentiated CSF-producing HCC cell lines (HA22T/VGH and SK-Hep-1) were macrophage-like in morphology, possessed nonspecific esterase (NSE) activity, and expressed CD14, CD68, and HLA-DR on their surface, while all the well-differentiated HCC cell lines were epithelioid and lacked myeloid differentiation antigens. These results suggest that monocytoid features and CSF production may be differentiation markers of hepatocytes at the immature stages, amd that the HA22T/VGH and SK-Hep-1 cell lines may be valuable tools for the study of hepatic function and differentiation.


Assuntos
Carcinoma Hepatocelular/metabolismo , Diferenciação Celular , Fatores Estimuladores de Colônias/biossíntese , Neoplasias Hepáticas/metabolismo , Fígado/citologia , Northern Blotting , Carcinoma Hepatocelular/patologia , Ensaio de Unidades Formadoras de Colônias , Meios de Cultivo Condicionados , Imunofluorescência , Fator Estimulador de Colônias de Granulócitos e Macrófagos/biossíntese , Fator Estimulador de Colônias de Granulócitos e Macrófagos/genética , Granulócitos/citologia , Histocitoquímica , Humanos , Fígado/metabolismo , Neoplasias Hepáticas/patologia , Macrófagos/citologia , RNA Mensageiro/biossíntese , Células Tumorais Cultivadas
7.
Eur J Hum Genet ; 9(9): 685-9, 2001 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11571557

RESUMO

Citrullinaemia is an inborn error of metabolism resulting from a deficiency of argininosuccinate synthetase. Previous studies of RNA of argininosuccinate synthetase of citrullinaemia patients using S1 nuclease analysis have identified a class of so-called RNA-negative alleles in which no stable mRNA can be detected. To investigate the nature of mutation responsible for such a phenotype, a compound heterozygous citrullinaemia carrying an RNA-negative allele and an allele with a 3' splice site mutation in intron 6 (IVS6-2A>G) was analysed. Using sequences of a DNA polymorphism and the IVS6-2A>G mutation as markers, approximately equal amounts of pre-mRNAs from allelic genes were detected suggesting that RNA-negative phenotype could not be the result of defect in transcription initiation. A C-to-T transition converting the CGA arginine codon at residue 279 to a TGA termination codon (R279X) was identified by cDNA sequencing. No accumulation of partially spliced pre-mRNAs containing introns immediately upstream and downstream of the nonsense mutation was observed. In addition, no mRNA species of abnormal size was detected when cDNA from the RNA-negative allele was analysed. Hence, there is no indication of nonsense-associated altered splicing (NAS). The most likely event responsible for the RNA-negative phenotype appears to be nonsense-mediated mRNA decay (NMD).


Assuntos
Argininossuccinato Sintase/genética , Citrulinemia/genética , RNA/genética , Alelos , Processamento Alternativo/genética , Citrulinemia/enzimologia , Códon sem Sentido , Análise Mutacional de DNA , DNA Complementar/química , DNA Complementar/genética , Humanos , Íntrons/genética , Mutação , Fenótipo , Polimorfismo Conformacional de Fita Simples , RNA/metabolismo , Precursores de RNA/genética , Precursores de RNA/metabolismo
8.
Am J Med Genet ; 38(4): 593-600, 1991 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-1676564

RESUMO

In our investigation of Duchenne muscular dystrophy (DMD)-Becker muscular dystrophy (BMD) gene in the Chinese, the analysis of relevant restriction fragment length polymorphisms (RFLPs) was first made in 30 normal female volunteers to determine their allele and genotype frequencies, and then in 29 DMD-BMD families for informativeness of different combinations of RFLPs in making carrier detection and prenatal diagnosis. We further screened the mutant gene, first with four 5' end intronic, genomic probes (pERT87-1, pERT87-8, pERT87-15, and XJ1.1) which did not show any deletions, and then with all dystrophin cDNA probes which disclosed 13 partial gene deletions out of 29 patients studied (45%). The deletions were nonrandomly distributed, clustering primarily near the central region of the gene. Fifty percent of the deletions involved single exon-containing HindIII restriction fragments, and again most were located near the center of the gene, emphasizing the importance of this area. Some exceptions were found against the previous suggestion that intactness of translational open reading frame resulted in a BMD phenotype. Neither the location of the breakpoints nor the length of the deletions was useful in predicting a certain phenotype. One of our patients had an intriguing pattern of partial gene deletion that lost part of the gene at the 3' end. Carrier determination was attempted by use of dosage analyses or identification of junction fragments which greatly improved accuracy and reliability.


Assuntos
Deleção Cromossômica , DNA/química , Distrofina/genética , Distrofias Musculares/genética , Alelos , Povo Asiático/genética , Consanguinidade , Sondas de DNA , Éxons , Feminino , Frequência do Gene , Triagem de Portadores Genéticos , Marcadores Genéticos , Humanos , Íntrons , Masculino , Distrofias Musculares/diagnóstico , Linhagem , Polimorfismo de Fragmento de Restrição , Diagnóstico Pré-Natal
9.
DNA Cell Biol ; 17(5): 415-25, 1998 May.
Artigo em Inglês | MEDLINE | ID: mdl-9628585

RESUMO

A hepatitis B virus (HBV) integrant was cloned from the genomic DNA library of human hepatocellular carcinoma cell line, Hep3B. Sequence analysis of the restriction fragment bearing the virus-host junction revealed that its integration pattern was the common type, with the right junction located at the cohesive region. The open reading frame of the major viral surface antigen was intact with rearranged preS1 and core sequences. The X protein, although truncated, maintained the trans-activating activity to simian virus 40 enhancer/promoter. S1 nuclease mapping showed that 4.0-, 2.9-, and 2.2-kb HBV RNAs detected in Hep3B cells were transcribed from this integrant using preS2/S promoter. By somatic-cell hybrid mapping, the left and right cellular flanking sequences were assigned to chromosomes 13 and 4, respectively. The results of this study support the notion that integrated hepatitis B virus, resulting in chromosomal rearrangement as well as the production of the carboxy-terminal truncated X protein with trans-activating activity, is important for viral hepatocarcinogenesis.


Assuntos
Cromossomos Humanos Par 13/genética , Vírus da Hepatite B/genética , Translocação Genética , Integração Viral/genética , Clonagem Molecular , DNA Viral/análise , Humanos , Regiões Promotoras Genéticas/genética , RNA Viral/metabolismo , Transcrição Gênica , Ativação Transcricional , Células Tumorais Cultivadas
10.
DNA Cell Biol ; 17(8): 717-25, 1998 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-9726254

RESUMO

Citrullinemia is a human genetic disease caused by a deficient argininosuccinate synthetase. In fibroblasts established from a citrullinemia patient with a mutation at the 3' splice site of the terminal intron of the gene, three cryptic 3' splice sites; i.e., SA1275, SA1636, and SA1663, residing on the terminal exon were activated. The usage of the cryptic sites showed a gradient, with the most downstream site having the highest usage; i.e., SA1663 > SA1636 > SA1275. However, when these cryptic sites were relocated to the internal exon, SA1636 was used the most. The splice-site strength of SA1636 was at least 10-fold higher than that of SA1663 in this situation. The results suggest that the preferential usage of SA1663 residing on the terminal exon may depend on its proximity to the poly(A) signal rather than on the strength of the splice site. Furthermore, when the strength of the downstream-most splice site increased, almost all the RNAs spliced to this site. However, in the presence of the wild-type splice site, all the RNAs were processed to the authentic site. Apparently, the selection of splice site can be revealed only when the sites being selected do not differ too much in their strength. By using a naturally occurring human mutant gene as a model, this study reveals that polyadenylation may play an important role in the selection of splice site during terminal exon definition.


Assuntos
Erros Inatos do Metabolismo dos Aminoácidos/genética , Argininossuccinato Sintase/genética , Citrulina/sangue , Splicing de RNA , Células Cultivadas , Fibroblastos/citologia , Humanos , Precursores de RNA/metabolismo , RNA Mensageiro/metabolismo
11.
J Virol Methods ; 51(1): 61-73, 1995 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-7730438

RESUMO

Molecular genetic studies have revealed that the human hepatitis B viral (HBV) Pol protein, a polypeptide of about 94 kDa, contains four domains. These are the 5'-terminal protein, spacer, RNA reverse transcriptase/DNA polymerase, and RNase H, respectively, from the amino (N) to carboxy (C) terminus. No evidence indicates as yet the involvement of a specific protease in cleaving the Pol protein or the presence of protease-cutting sites in the Pol protein. An in vitro-translated Pol protein was shown to be cleaved by purified thrombin but not in the presence of its inhibitor, hirudin. Two thrombin-cutting sites, spanning 194 amino acids, were then deduced by thrombin digestion of Pol protein with various lengths of C-terminal deletion. These two putative cutting sites, one located in the spacer region and the other in the beginning of the polymerase region, were found to be conserved at similar positions in the Pol protein of all hepadnaviruses. By using a novel method called the LacZ localization assay (LLA), it was demonstrated that a tripartite fusion protein containing the nucleus localization sequence (NLS) of SV40 large T Ag, the putative thrombin cutting sequence (Ile-Arg-Ile-Pro-Arg320-Thr) of HBV Pol protein and the full length beta-galactosidase of E. coli, exhibited a lower percentage (approximately 53%) of targeting into the nucleus of transfected hepatoma cells when compared with a similar tripartite protein containing a single mutation (Arg320 residue into Trp320) of HBV Pol protein (approximately 78%) or with a bipartite protein of SV40 NLS-beta-galactosidase (approximately 90%). These results indicate that the putative thrombin-cutting site in the spacer region of HBV Pol protein could be cleaved by a cellular protease resulting in the separation of NLS sequence from the beta-galactosidase and rendering a lower frequency of X-gal staining in the nucleus.


Assuntos
Produtos do Gene pol/genética , Vírus da Hepatite B/genética , Sequência de Aminoácidos , Antígenos Virais de Tumores/genética , Sequência de Bases , Sítios de Ligação , Mapeamento Cromossômico , DNA Viral/genética , Endopeptidases , Escherichia coli/genética , Genes Virais , Humanos , Óperon Lac , Dados de Sequência Molecular , Plasmídeos/genética , Proteínas Recombinantes de Fusão/genética , Trombina , Transfecção , Células Tumorais Cultivadas , Virologia/métodos
12.
Chin Med J (Engl) ; 104(12): 971-4, 1991 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-1782815

RESUMO

Recently, we surveyed thyroid function and TSH concentration of villagers in an endemic goiter area where iodized salt had been supplied for 25 years; it was found that the serum FT3 and TSH levels determined with immunoradiometric analysis (IRMA) were higher and the FT4 level was lower than that of the controls. It was shown that the inhabitants of the endemic goiter area had subclinical hypothyroidism based on the "ultrasensitive" method for TSH assay. We suggest that the best biochemical techniques for monitoring the iodized salt prophylaxis program and the physiological response of the villagers to iodine should be the periodical measurement of serum TSH level using ultrasensitive assay and determination of FT4 level.


Assuntos
Bócio Endêmico/prevenção & controle , Iodo/administração & dosagem , Sódio na Dieta/administração & dosagem , Tireotropina/sangue , Anticorpos Monoclonais/imunologia , Bócio Endêmico/sangue , Humanos , Hipotireoidismo/sangue , Ensaio Imunorradiométrico , Tireotropina/imunologia , Tiroxina/sangue , Tri-Iodotironina/sangue
13.
Zhonghua Nei Ke Za Zhi ; 30(11): 703-5, 731, 1991 Nov.
Artigo em Zh | MEDLINE | ID: mdl-1815875

RESUMO

Recently we surveyed the thyroid function and TSH concentration of villagers in an endemic goiter area where iodized salt had been supplied for 25 years. We found that the serum FT3 and TSH (IRMA) level of villagers were higher and the FT4 level was lower than those of the controls, comparing with the RIA, which suggested that the inhabitants of the endemic goiter area had subclinical hypothyroidism based on the IRMA method for TSH assay. Therefore, we suggest that the best biochemical technique for monitoring the iodized salt prophylaxis program and the physiological response of villagers to iodine is measurement of serum TSH level with the ultrasensitive assay and FT4 level periodically.


Assuntos
Bócio Endêmico/sangue , Iodo/administração & dosagem , Tireotropina/sangue , Adolescente , Adulto , Idoso , Criança , Bócio Endêmico/prevenção & controle , Humanos , Hipotireoidismo/prevenção & controle , Ensaio Imunorradiométrico , Pessoa de Meia-Idade , Tiroxina/sangue , Tri-Iodotironina/sangue
14.
Asia Pac J Public Health ; 3(4): 301-5, 1989.
Artigo em Inglês | MEDLINE | ID: mdl-2638910

RESUMO

The thyroid function and TSH concentration of villagers in an endemic goiter area in China where iodized salt had been supplied for twenty-five years were surveyed. We found that the serum FT3 and TSH (IRMA) levels of villagers were higher and the FT4 levels was lower than those of the controls, which suggested that the inhabitants of the endemic goiter area had subclinical hypothyroidism based on the ultrasensitive method for TSH assay. Therefore, we suggest that the best biochemical techniques for monitoring the iodized salt prophylaxis program and the physiological response of villagers to iodine are measurements of serum TSH level and FT4 level periodically.


Assuntos
Bócio Endêmico/sangue , Sódio na Dieta/administração & dosagem , Tireotropina/sangue , Tiroxina/sangue , Tri-Iodotironina/sangue , Adolescente , Adulto , Idoso , Criança , China , Humanos , Pessoa de Meia-Idade , Radioimunoensaio , Análise de Regressão , Fatores de Tempo
15.
Kidney Int ; 69(1): 165-72, 2006 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16374439

RESUMO

Heme oxygenase-1 (HO-1) is a rate-limiting enzyme in heme degradation, producing carbon monoxide (CO), which carries potent antiproliferative and anti-inflammatory effects in the vascular walls. Transcription of the HO-1 gene is regulated by the length polymorphism of dinucleotide guanosine thymine repeat (GT)(n) in the promoter region, which was measured in this study to determine its association with arteriovenous fistula (AVF) failure in Chinese hemodialysis (HD) patients in Taiwan. L allele means (GT)(n)>or=30 and S allele means (GT)n<30. Therefore, there are two L alleles for L/L genotype, one L and one S allele for L/S genotype, and two S alleles for S/S genotype. Among the 603 HD patients who were enrolled in this study, 178 patients had history of AVF failure, while 425 patients did not. Significant associations were found between AVF failure and the following factors (hazard ratio): longer HD duration (1.004 month), lower pump flow (0.993 ml/min), higher dynamic venous pressure (1.010 mmHg), location of AVF on the right side (1.587 vs left side) and upper arm (2.242 vs forearm), and L/L and L/S genotypes of HO-1 (2.040 vs S/S genotype). The proportion of AVF failure increased from 20.3% in S/S genotype and 31.0% in L/S genotype to 35.4% in L/L genotype (P=0.011). Relative incidences were 1/87.6 (1 episode per 87.6 patient-months), 1/129, and 1/224.9 for HD patients with L/L, L/S, and S/S genotypes, respectively (P<0.002). The unassisted patency of AVF at 5 years decreased significantly from 83.8% (124/148) to 75.1% (223/297) and 69% (109/158) in S/S, L/S, and L/L genotypes, respectively (P<0.0001). In comparison with HD patients with S/S genotype, those with L/L genotype had a higher prevalence of coronary artery disease (29.1 vs 14.2%; P=0.005). A longer length polymorphism with (GT)(n) >or=30 in the HO-1 gene was associated with a higher frequency of access failure and a poorer patency of AVF in HD patients. The longer GT repeat in the HO-1 promoter might inhibit gene transcription, and consequently offset the CO-mediated protective effect against vascular injury.


Assuntos
Derivação Arteriovenosa Cirúrgica/efeitos adversos , Repetições de Dinucleotídeos , Heme Oxigenase-1/genética , Polimorfismo Genético , Adulto , Idoso , Monóxido de Carbono/metabolismo , Feminino , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade , Regiões Promotoras Genéticas , Análise de Regressão
16.
Conf Proc IEEE Eng Med Biol Soc ; 2005: 6104-7, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-17281656

RESUMO

In this study, an oncology treatment planning system was developed by integrating the techniques of computer graphics, virtual reality (VR) and three dimensional (3D) image reconstruction. The virtual treatment room was constructed according to the real space, and the 3D data of patient's body was reconstructed from computer tomography (CT) slices in order to provide the 3D clinical information to compare with the therapy in real world. In addition, the virtual multi-leaf collimator (MLC) was constructed to simulate and visualize both the radiation and irradiation fields. All objects in the system had been scaled down according to the true size. The system can be expected to save the preparation time and can be used for teaching and training prior to a real therapy.

17.
Eur J Biochem ; 229(1): 233-8, 1995 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-7538074

RESUMO

The Canr1 cell line, a canavanine-resistant variant of the cultured human epithelial cell line, RPMI 2650, overproduces argininosuccinate synthetase more than 200-fold. Run-on transcription assays showed no significant difference in transcription initiation of the argininosuccinate synthetase gene between Canr1 and RPMI 2650 cells. Furthermore, no difference in the relative transcription rate was seen along this 63-kb gene, suggesting that neither transcription initiation nor elongation is responsible for differential expression of argininosuccinate synthetase in these two cell lines. However, when isolated nuclei were labeled for a longer period of time in the transcription assay, precursor RNA of argininosuccinate synthetase in RPMI 2650 cells was found to be very labile. Apparently, a nuclear event affecting precursor RNA stability is responsible for the dramatic difference in argininosuccinate synthetase levels in these two cell lines. Using a microsatellite polymorphic marker, it was demonstrated that argininosuccinate synthetase from both alleles of the gene in Canr1 cells was overexpressed. This suggests that a trans-acting mechanism may be responsible for regulation of overproduction in this cell line. Furthermore, when protein synthesis was blocked by cycloheximide, less precursor RNA was observed in Canr1 cells. These data suggest that a labile protein factor(s) participates in the regulation.


Assuntos
Argininossuccinato Sintase/biossíntese , Canavanina/farmacologia , Processamento Pós-Transcricional do RNA , Sequência de Bases , Linhagem Celular , Núcleo Celular/metabolismo , DNA Complementar , Resistência a Medicamentos , Epitélio/enzimologia , Humanos , Dados de Sequência Molecular , RNA/análise
18.
J Gen Virol ; 80 ( Pt 7): 1769-1776, 1999 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10423146

RESUMO

Hepatitis B virus (HBV) DNA polymerase (P) is translated from a bicistronic pregenomic RNA via a ribosomal leaky scanning mechanism. Another viral transcript, the preC RNA, differs from pregenomic RNA by the presence of some 30 nt at the 5' end that encompass the preC initiation codon. This RNA is used exclusively for expression of the precore protein which is a precursor of secreted HBeAg. Factors leading to inefficient translation of the P and C proteins from the preC RNA were explored using a genetic approach in transient transfection assays. Our data indicate that when translating the precore protein, the elongation arrest that occurs during targeting of nascent polypeptide chains to the endoplasmic reticulum interferes with the scanning of the 40S ribosomal subunits. Such interference seems to hinder initiation of the ribosomes at the downstream genes. Furthermore, the presence of the preC initiator codon in the preC mRNA has resulted in a reduction in the number of scanning ribosomes reaching the C and P initiator codons compared with the case of pregenomic RNA. Finally, although the preC initiator codon is in a suboptimal context for translation initiation, an RNA secondary structure, the encapsidation signal, located downstream to the initiator codon is shown to enhance codon recognition, resulting in a depletion of the number of 40S ribosomal subunits available for scanning of the downstream AUG codons. This study demonstrates that the HBV encapsidation signal plays an additional role in facilitating recognition of the preC initiator codon.


Assuntos
Regulação Viral da Expressão Gênica , Vírus da Hepatite B/fisiologia , RNA Mensageiro/genética , RNA Viral/genética , Replicação Viral/genética , Sequência de Aminoácidos , Sequência de Bases , DNA Polimerase Dirigida por DNA/genética , Humanos , Dados de Sequência Molecular , Biossíntese de Proteínas
19.
J Gen Virol ; 79 ( Pt 9): 2181-9, 1998 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-9747727

RESUMO

Hepatitis B virus (HBV) polymerase (P) gene is translated from the bicistronic pregenomic RNA with the core (C) gene in the first cistron. The P ORF is preceded by the C AUG and three AUG codons within the C region, where a minicistron of 7 amino acids can potentially be translated. Our results indicate that the efficiency of the P gene translation initiation was about 10% of that of the C gene when both genes were fused in-frame to a lacZ reporter in an mRNA similar in structure to the pregenomic RNA. By mutational analysis, about 74% of the translation initiation of HBV P gene was shown to be by ribosomes that reinitiated after terminating translation of this minicistron, while the rest was by two mechanisms: one by ribosomes leaky scanning through every upstream AUG and the other by ribosomal backwards scanning to the P AUG after finishing the translation of the C gene. The efficiency of termination-reinitiation depended on the size of the minicistron, i.e. the reinitiation efficiency decreased about 50% when the size increased from 24 nt to 57 nt. When a 44 nt HBV sequence comprising the minicistron was inserted at the 5' untranslated region of the cat gene, CAT expression was regulated in a similar way to that of the HBV P gene. Moreover, when transfection occurred with an HBV expression plasmid containing an inactivated minicistron, production of virus-like particles dropped to about one-third of the wild-type level, suggesting that the termination-reinitiation mechanism is indeed important for HBV P gene expression.


Assuntos
Produtos do Gene pol/genética , Genes Virais , Vírus da Hepatite B/enzimologia , Vírus da Hepatite B/genética , DNA Polimerase Dirigida por RNA/genética , Sequência de Aminoácidos , Fusão Gênica Artificial , Sequência de Bases , Linhagem Celular , Regulação Viral da Expressão Gênica , Genes , Genes Reporter , Vírus da Hepatite B/fisiologia , Humanos , Óperon Lac , Mutação , Terminação Traducional da Cadeia Peptídica , Plasmídeos/genética , Biossíntese de Proteínas , Ribossomos/metabolismo , Replicação Viral/genética
20.
J Biol Chem ; 265(32): 19716-20, 1990 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-2246255

RESUMO

The cloned argininosuccinate synthetase gene from a citrullinemia patient's fibroblast cell line revealed a single base substitution (G to C) within the splice acceptor site of the last intron. The mutation abolished normal RNA splicing, and, by cDNA analysis, three abnormal splicing pathways were demonstrated. The major pathway involved the activation of a cryptic acceptor site in the last exon that resulted in a deletion of seven nucleotides in the mature RNA. Another pathway involved a downstream cryptic acceptor site, that is 388 nucleotides downstream from the first cryptic site. Northern blot analysis showed that this second cryptic site is present on the minor 2.7-kilobase mRNA, but not on the major species of argininosuccinate synthetase mRNA, which is 1.7-kilobases in length. Using this aberrant cDNA as a probe, the cDNA of the 2.7-kilobase mRNA was isolated and studied. Sequence analysis suggests that this species of RNA is the one that bypasses the polyadenylation signal employed by the 1.7-kilobase RNA. Since both transcripts encounter the same translation termination codon, both RNAs should encode identical protein. Furthermore, a tract of 22 repeats of d(CA).(GT) is found at the 3' end of the gene and this repeat sequence is present on the 2.7-kilobase RNA. The third pathway of the abnormal splicing revealed a rare class of transcript that has the last intron retained in the mature RNA. This study shows that in human the intron inclusion can occur through a naturally occurring point mutation. All these abnormally spliced RNAs resulted in a protein reading frame shift.


Assuntos
Erros Inatos do Metabolismo dos Aminoácidos/genética , Argininossuccinato Sintase/genética , Citrulina/sangue , Mutação , Splicing de RNA/genética , Erros Inatos do Metabolismo dos Aminoácidos/enzimologia , Sequência de Bases , Linhagem Celular , DNA/genética , Éxons , Fibroblastos/enzimologia , Humanos , Íntrons , Dados de Sequência Molecular , Hibridização de Ácido Nucleico , RNA Mensageiro/genética , Sequências Repetitivas de Ácido Nucleico , Mapeamento por Restrição
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