RESUMO
BACKGROUND: Median overall survival (OS) for women with high-grade serous ovarian cancer (HGSOC) is â¼4 years, yet survival varies widely between patients. There are no well-established, gene expression signatures associated with prognosis. The aim of this study was to develop a robust prognostic signature for OS in patients with HGSOC. PATIENTS AND METHODS: Expression of 513 genes, selected from a meta-analysis of 1455 tumours and other candidates, was measured using NanoString technology from formalin-fixed paraffin-embedded tumour tissue collected from 3769 women with HGSOC from multiple studies. Elastic net regularization for survival analysis was applied to develop a prognostic model for 5-year OS, trained on 2702 tumours from 15 studies and evaluated on an independent set of 1067 tumours from six studies. RESULTS: Expression levels of 276 genes were associated with OS (false discovery rate < 0.05) in covariate-adjusted single-gene analyses. The top five genes were TAP1, ZFHX4, CXCL9, FBN1 and PTGER3 (P < 0.001). The best performing prognostic signature included 101 genes enriched in pathways with treatment implications. Each gain of one standard deviation in the gene expression score conferred a greater than twofold increase in risk of death [hazard ratio (HR) 2.35, 95% confidence interval (CI) 2.02-2.71; P < 0.001]. Median survival [HR (95% CI)] by gene expression score quintile was 9.5 (8.3 to -), 5.4 (4.6-7.0), 3.8 (3.3-4.6), 3.2 (2.9-3.7) and 2.3 (2.1-2.6) years. CONCLUSION: The OTTA-SPOT (Ovarian Tumor Tissue Analysis consortium - Stratified Prognosis of Ovarian Tumours) gene expression signature may improve risk stratification in clinical trials by identifying patients who are least likely to achieve 5-year survival. The identified novel genes associated with the outcome may also yield opportunities for the development of targeted therapeutic approaches.
Assuntos
Cistadenocarcinoma Seroso , Neoplasias Ovarianas , Cistadenocarcinoma Seroso/genética , Feminino , Humanos , Neoplasias Ovarianas/genética , Prognóstico , Modelos de Riscos Proporcionais , Análise de Sobrevida , TranscriptomaRESUMO
Promising composite coatings based on hematite (α-Fe2O3) mesocrystals of size 110 nm and chitosan (CHT) molecules for different biotechnological applications have been successfully obtained by electrophoretic deposition (EPD). Homogeneous and reproducible coatings have been obtained by studying and controlling the chemical interactions between both phases (α-Fe2O3 and CHT). A voltage of 25 V and a deposition time of 5 min were chosen as best deposition conditions, which resulted in highly homogeneous coatings with well-distributed α-Fe2O3 particles. According to TGA measurements, the content of α-Fe2O3 and chitosan in the final composite coating were found to be 74 and 26 wt%, respectively. The presence of both phases in the composite coating was determined by XRD analysis and the coatings microstructure was observed by SEM.
Assuntos
Quitosana/química , Materiais Revestidos Biocompatíveis/química , Compostos Férricos/química , Nanocompostos/química , EletroforeseRESUMO
Two organic/inorganic composite coatings based on alginate, as organic matrix, and zinc oxide nanoparticles (n-ZnO) with and without bioactive glass (BG), as inorganic components, intended for biomedical applications, were developed by electrophoretic deposition (EPD). Different n-ZnO (1-10 g/L) and BG (1-1.5 g/L) contents were studied for a fixed alginate concentration (2 g/L). The presence of n-ZnO was confirmed to impart antibacterial properties to the coatings against gram-negative bacteria Escherichia coli, while the BG induced the formation of hydroxyapatite on coating surfaces thereby imparting bioactivity, making the coating suitable for bone replacement applications. Coating composition was analyzed by thermogravimetric analysis (TG), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDS) analyses. Scanning electron microscopy (SEM) was employed to study both the surface and the cross section morphology of the coatings. Polarization curves of the coated substrates made in cell culture media at 37 °C confirmed the corrosion protection function of the novel organic/inorganic composite coatings.
Assuntos
Alginatos/química , Antibacterianos/química , Materiais Revestidos Biocompatíveis/química , Vidro/química , Óxido de Zinco/química , Antibacterianos/farmacologia , Corrosão , Durapatita/química , Eletroforese/métodos , Escherichia coli/efeitos dos fármacos , Ácido Glucurônico/química , Ácidos Hexurônicos/química , Microscopia Eletrônica de Varredura/métodos , Nanopartículas/química , Espectrometria por Raios X/métodos , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Difração de Raios X/métodosRESUMO
The pathologic and immunohistochemical features of familial epithelial ovarian cancers are not well understood. We have carried out a comprehensive immunohistochemical study of familial ovarian carcinomas from women with and without BRCA1 or BRCA2 mutations, in order to identify specific and/or common features among these different familial case groups (BRCA1, BRCA2 and non-BRCA1/2) and to identify markers of diagnostic value that might help to select more specific treatments. 73 familial primary ovarian carcinomas were analyzed for the expression of 40 antibodies involved in different genetic pathways using a tissue microarray. Serous carcinomas comprised the majority of all three familial case groups. On the other hand, BRCA1 and BRCA2 carcinomas have similar histopathologic features; i.e. they are often high-grade and are usually diagnosed at a more advanced FIGO stage than non-BRCA1/2 carcinomas. In our series, BRCA1 carcinomas had better clinical evolution and they also more frequently over-expressed PR and P53 than BRCA2 and non-BRCA1/2 carcinomas. Unsupervised cluster analysis and survival analysis identified ERCC1 as a potential marker of better clinical outcome for hereditary epithelial ovarian cancer.
Assuntos
Neoplasias Epiteliais e Glandulares/genética , Neoplasias Epiteliais e Glandulares/metabolismo , Neoplasias Epiteliais e Glandulares/patologia , Neoplasias Ovarianas/genética , Neoplasias Ovarianas/metabolismo , Neoplasias Ovarianas/patologia , Carcinoma Epitelial do Ovário , Feminino , Genes BRCA1 , Genes BRCA2 , Humanos , Imuno-Histoquímica , Pessoa de Meia-Idade , Gradação de Tumores , Estadiamento de Neoplasias , Fenótipo , Análise Serial de TecidosRESUMO
Modern electrochemical devices require the morphological control of the active material. In this paper the synthesis of nickel hydroxide, as common active compound of such devices, is presented. The influence of ultrasound in the synthesis of nickel hydroxide from aqueous ammonia complexes is studied showing that ultrasound allows the fabrication of flower-like particles with sizes ranging in between 0.7 and 1.0µm in contrast with the 6-8µm particles obtained in the absence of ultrasound. The influence of gas flow, temperature of the process and surfactants in the ultrasonically prepared powders is discussed in term of shape, size and agglomeration of the particles. Adjusting the experimental condition, spherical or platelet-like particles are obtained with sizes ranging from 1.3µm to 200nm.
RESUMO
BACKGROUND AND OBJECTIVE: Tuberculosis is an infectious disease currently having great importance in the daily clinical practice in Spain. Some cases of active tuberculosis are not identified until after the patient had died and an autopsy has been performed. This study has analyzed the clinical and pathological characteristics of patients diagnosed with active tuberculosis in the autopsy. MATERIAL AND METHOD: We reviewed all the autopsies performed in the University Hospital 12 de Octubre of Madrid between 1974 and 2002. The autopsy reports and clinical records were examined in those cases in which active tuberculosis was found. RESULTS: We found 92 cases of active tuberculosis, 57% corresponding to men. Mean age of this group was 64 years. A total of 20% of the patients died within 48 hours after admission. Predisposing factors were identified in 90% of the cases. Dyspnea (24% of cases) and wasting syndrome (23%) were the main symptoms that motivated patients to request medical attention. Up to 30% of cases had normal chest X-ray. Tuberculosis was suspected in only 46% of patients before death. Principal cause of death was tuberculosis in 61% of patients, 52% of patients had pulmonary tuberculosis, 28% suffered from miliary tuberculosis and 20% from extra-pulmonary tuberculosis. The lungs were the most frequently affected organ. Epithelioid granulomas were found in all patients. CONCLUSIONS: Tuberculosis is an uncommon finding in the autopsy as the cause of death. The presence of unspecific symptomatology, insufficient cost-effectiveness of the diagnostic tests and precocious death, are identified as the most frequent causes of undiagnosed tuberculosis.
Assuntos
Autopsia , Tuberculose/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Espanha , Tuberculose/epidemiologiaRESUMO
Ubiquitination is a post-translational modification in which a small conserved peptide, ubiquitin, is appended to target proteins in the cell, through a series of complex enzymatic reactions. Recently, a particular form of ubiquitination, monoubiquitination, has emerged as a nonproteolytic reversible modification that controls protein function. In this review, we highlight recent findings on monoubiquitination as a signaling-induced modification, controlled, among others, by pathways originating from active receptor tyrosine kinases. Furthermore, we review the major cellular processes controlled by ubiquitin modification, including membrane trafficking, histone function, transcription regulation, DNA repair, and DNA replication.
Assuntos
Membrana Celular/metabolismo , Transdução de Sinais , Ubiquitina/metabolismo , Animais , Reparo do DNA , Replicação do DNA , Endocitose , Anemia de Fanconi/metabolismo , Humanos , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas c-cbl , Receptores Proteína Tirosina Quinases/metabolismo , Saccharomyces cerevisiae , Ubiquitina-Proteína Ligases/metabolismoRESUMO
To determine whether Gilbert's syndrome increases the risk of gallstone formation in children with chronic hemolytic disease, we studied 44 children with this diagnosis. Gallstones were detected by abdominal ultrasonography. This took place annually in scheduled examinations or in the context of acute abdominal pain. In all patients, the mean values of hemoglobin, reticulocyte and serum bilirubin in the chronic phase were recorded. In addition, TA insertion in the A(TA)nTATAA motif within the promoter region of the enzyme uridine-diphosphate-glucuronyl transferase (UGT1A1) was screened, since this is typically associated with GS.We found 10 (22.7 %) homozygotes for the mutated allele TA*7/TA*7, 12 (27.3 %) TA*6/TA*6 heterozygotes and 22 (50 %) homozygotes for the wild-type allele TA*6/TA*6. No statistically significant differences were found in the values of hemoglobin (Kruskal-Wallis test 2.496; p > 0.05) or in reticulocyte count (Kruskal-Wallis test 1.696; p > 0,05) between the three groups of patients, suggesting a similar degree of hemolysis. Patients with the UGT1A1 TA*7/TA*7 genotype showed higher mean serum bilirubin levels than did patients who were homozygous for the wild-type allele (Mann-Whitney test 35.5; p < 0.05). None of the patients with the TA*6/TA*6 genotype developed gallstones, whereas this complication was found in 2 of 12 (16.6 %) heterozygotes and 6 of 10 (60 %) homozygotes for the allele with TA insertion. In this latter group, 4 patients presented acute pancreatitis as a consequence of gallstone formation.The association between increased bilirubin load due to chronic hemolytic disease and diminished hepatic conjugation leads to raised serum bilirubin levels and consequently to an increased risk of gallstone formation. Therefore, we recommend screening for Gilbert's syndrome in children in the initial phases of chronic hemolytic diseases.
Assuntos
Cálculos Biliares , Doença de Gilbert , Bilirrubina/sangue , Criança , Cálculos Biliares/genética , Genótipo , Doença de Gilbert/diagnóstico , Glucuronosiltransferase/genética , Humanos , Regiões Promotoras GenéticasRESUMO
Many cellular processes rely on the ordered assembly of macromolecular structures. Here, we uncover an unexpected link between two such processes, endocytosis and transcription. Many endocytic proteins, including eps15, epsin1, the clathrin assembly lymphoid myeloid leukemia (CALM), and alpha-adaptin, accumulate in the nucleus when nuclear export is inhibited. Endocytosis and nucleocytoplasmic shuttling of endocytic proteins are apparently independent processes, since inhibition of endocytosis did not appreciably alter nuclear translocation of endocytic proteins, and blockade of nuclear export did not change the initial rate of endocytosis. In the nucleus, eps15 and CALM acted as positive modulators of transcription in a GAL4-based transactivation assay, thus raising the intriguing possibility that some endocytic proteins play a direct or indirect role in transcriptional regulation.
Assuntos
Núcleo Celular/metabolismo , Citoplasma/metabolismo , Endocitose/fisiologia , Proteínas Monoméricas de Montagem de Clatrina , Proteínas de Saccharomyces cerevisiae , Proteínas de Transporte Vesicular , Transporte Ativo do Núcleo Celular/fisiologia , Subunidades alfa do Complexo de Proteínas Adaptadoras , Proteínas Adaptadoras de Transdução de Sinal , Proteínas Adaptadoras de Transporte Vesicular , Animais , Proteínas de Ligação ao Cálcio/metabolismo , Proteínas de Transporte/metabolismo , Linhagem Celular , Chlorocebus aethiops , Proteínas de Ligação a DNA , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Células HeLa , Humanos , Peptídeos e Proteínas de Sinalização Intracelular , Proteínas de Membrana/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Neuropeptídeos/metabolismo , Fosfoproteínas/metabolismo , Transporte Proteico/fisiologia , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Transdução de Sinais/fisiologia , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Transcrição Gênica/fisiologia , Ativação Transcricional/fisiologiaRESUMO
Certain chemokines act as natural antagonists of human immunodeficiency virus (HIV) by blocking key viral coreceptors, such as CCR5 and CXCR4, on the surface of susceptible cells. Elucidating the structural determinants of the receptor-binding and HIV-inhibitory functions of these chemokines is essential for the rational design of derivative molecules of therapeutic value. Here, we identify the structural determinants of CCR5 recognition and antiviral activity of the CC chemokine RANTES, showing that critical residues form a solvent-exposed hydrophobic patch on the surface of the molecule. Moreover, we demonstrate that the biological function is critically dependent on dimerization, resulting in the exposure of a large ( approximately 180 A2), continuous hydrophobic surface. Relevant to the development of novel therapeutic approaches, we designed a retroinverted RANTES peptide mimetic that maintained both HIV- and chemotaxis-antagonistic functions.
Assuntos
Fármacos Anti-HIV/química , Fármacos Anti-HIV/metabolismo , Quimiocina CCL5/química , Quimiocina CCL5/metabolismo , HIV-1/metabolismo , Receptores CCR5/metabolismo , Alanina/genética , Alanina/metabolismo , Sequência de Aminoácidos , Fármacos Anti-HIV/farmacologia , Antagonistas dos Receptores CCR5 , Linhagem Celular , Quimiocina CCL5/análogos & derivados , Quimiocina CCL5/farmacologia , Quimiotaxia de Leucócito/efeitos dos fármacos , Técnicas de Cocultura , Dimerização , Desenho de Fármacos , Células Gigantes/efeitos dos fármacos , Células Gigantes/virologia , HIV-1/efeitos dos fármacos , Humanos , Linfócitos/efeitos dos fármacos , Linfócitos/imunologia , Modelos Moleculares , Mimetismo Molecular , Mutagênese/genética , Peptídeos/síntese química , Peptídeos/química , Peptídeos/metabolismo , Peptídeos/farmacologia , Ligação Proteica , Conformação Proteica , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/farmacologia , Reprodutibilidade dos Testes , Relação Estrutura-AtividadeRESUMO
We have studied the photosensitizing effects of zinc(II)-phthalocyanine (ZnPc) on the cytoskeleton of HeLa cells using sublethal (10(-7) M, followed by 1 or 3 min of red light to induce 20%, LD20, or 60%, LD60, cell death, respectively) or lethal (5 x 10(-6) M and 15 min of irradiation, LD100) experimental conditions. The immunofluorescent analysis of the cytoskeleton showed a variable photodamage to microtubules (MT), actin microfilaments (AF) and intermediate filaments of keratin (KF), as well as on alpha-actinin, which was dependent on treatment conditions. Both sublethal treatments induced deep alterations on interphase and mitotic MT. The mitotic index increased with time with the maximum at 18 h (12%) or 24 h (14%) after LD20 or LD60, respectively. The alterations on AF and alpha-actinin were much more severe than those observed on KF at any evaluated time. With the exception of the KF, which remained partially organized, the MT and AF network was severely damaged by the lethal treatment. Western blot analysis for alpha-tubulin, G-actin and alpha-actinin from soluble and insoluble fractions confirmed the results observed by immunofluorescence, thus indicating that these cytoskeletal components are involved in cell damage and death by ZnPc photosensitization.
Assuntos
Actinina/efeitos dos fármacos , Actinas/efeitos dos fármacos , Indóis/farmacologia , Queratinas/efeitos dos fármacos , Microtúbulos/efeitos dos fármacos , Compostos Organometálicos/farmacologia , Fármacos Fotossensibilizantes/farmacologia , Células HeLa , Humanos , Isoindóis , Fotoquimioterapia , Compostos de ZincoRESUMO
Although selected chemokines act as natural inhibitors of human immunodeficiency virus (HIV) infection, their inherent proinflammatory activity may limit a therapeutic use. To elucidate whether the antiviral and signaling functions of RANTES can be dissociated, several recombinant analogues mutated at the N terminus were generated and functionally compared with the wild-type (WT) molecule, as well as with three previously described mutants. Substitution of selected residues within the N-terminal region caused a marked loss of antiviral potency. By contrast, two unique analogues (C1.C5-RANTES and L-RANTES) exhibited an increased antiviral activity against different CXCR4-negative HIV-1 isolates grown in primary mononuclear cells or in macrophages. This enhanced HIV-blocking activity was associated with an increased binding affinity for CCR5. Both C1.C5-RANTES and L-RANTES showed a dramatically reduced ability to trigger intracellular calcium mobilization via CCR3 or CCR5, while potently antagonizing the action of the WT chemokine. By contrast, two previously described analogues (RANTES(3-68) and AOP-RANTES) maintained a WT ability to trigger CCR5-mediated signaling, while a third one (RANTES(9-68)) showed a dramatic loss of antiviral activity. These data demonstrate that the antiviral and signaling functions of RANTES can be uncoupled, opening new perspectives for the development of chemokine-based therapeutic approaches for HIV infection.
Assuntos
Fármacos Anti-HIV/química , Quimiocina CCL5/química , HIV-1/efeitos dos fármacos , Fármacos Anti-HIV/imunologia , Fármacos Anti-HIV/farmacologia , Quimiocina CCL5/imunologia , Quimiocina CCL5/farmacologia , Humanos , Receptores CCR5/imunologia , Relação Estrutura-AtividadeRESUMO
The flavivirus dengue 1 Western Pacific,74 (DEN1 WP) virus has a positive-stranded RNA genome of 10,735 nucleotides. DEN1 WP genomic RNA was amplified into three overlapping fragments by RT-PCR. These fragments were assembled into a full-length cDNA clone in the yeast-E. coli shuttle vector pRS424, using homologous recombination in yeast. RNA produced by in vitro transcription of this clone was infectious upon electroporation into LLCMK2 cells, as shown by cytopathic effects and detection of viral antigens by indirect immunofluorescence, and by propagation of the virus released into the culture media. Biological properties of the transcript-derived virus, such as the pattern of dengue-specific protein synthesis and growth rate in LLCMK2 or C6/36 cells, resembled those of the parent DEN1 WP virus.
Assuntos
Vírus da Dengue/genética , Genoma Viral , Animais , Linhagem Celular , Clonagem Molecular , Efeito Citopatogênico Viral , Vírus da Dengue/patogenicidade , Escherichia coli/genética , Vetores Genéticos , Humanos , RNA Viral/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transcrição Gênica , Proteínas Virais/análise , Leveduras/genéticaRESUMO
RANTES (regulated on activation, normal T cell expressed and secreted), a C-C chemokine, is one of the major HIV-suppressive factors produced by CD8+ T cells. Wild-type RANTES and genetically modified analogues were expressed in a baculovirus system and purified from cell culture supernatants employing a multi-step strategy based on affinity and RP-HPLC. Quantification and purity control of the final proteins were carried out by capillary electrophoresis using the synthetic or the recombinant wild-type RANTES as a reference. The procedure here reported requires only three days to obtain 0.016-0.270 mg of the pure and characterised proteins, starting from 370-900 ml of culture media, and is suitable for the analysis of a large number of RANTES analogues.
Assuntos
Quimiocina CCL5/isolamento & purificação , Mutação , Baculoviridae/genética , Linhagem Celular , Quimiocina CCL5/genética , Quimiocina CCL5/farmacologia , Cromatografia de Afinidade/métodos , Cromatografia Líquida de Alta Pressão/métodos , Eletroforese Capilar , Ensaio de Imunoadsorção Enzimática , Humanos , Espectrometria de Massas , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/farmacologiaRESUMO
Human immunodeficiency virus type 1 (HIV-1) infection of the brain is associated with neurological manifestations both in adults and in children. The primary target for HIV-1 infection in the brain is the microglia, but astrocytes can also be infected. We tested 26 primary HIV-1 isolates for their capacity to infect human fetal astrocytes in culture. Eight of these isolates, independent of their biological phenotype and chemokine receptor usage, were able to infect astrocytes. Although no sustained viral replication could be demonstrated, the virus was recovered by coculture with receptive cells such as macrophages or on stimulation with interleukin-1beta. To gain knowledge into the molecular events that regulate attachment and penetration of HIV-1 in astrocytes, we investigated the expression of several chemokine receptors. Fluorocytometry and calcium-mobilization assay did not provide evidence of expression of any of the major HIV-1 coreceptors, including CXCR4, CCR5, CCR3, and CCR2b, as well as the CD4 molecule on the cell surface of human fetal astrocytes. However, mRNA transcripts for CXCR4, CCR5, Bonzo/STRL33/TYMSTR, and APJ were detected by RT-PCR. Furthermore, infection of astrocytes by HIV-1 isolates with different chemokine receptor usage was not inhibited by the chemokines SDF-1beta, RANTES, MIP-1beta, or MCP-1 or by antibodies directed against the third variable region or the CD4 binding site of gp120. These data show that astrocytes can be infected by primary HIV-1 isolates via a mechanism independent of CD4 or major chemokine receptors. Furthermore, astrocytes are potential carriers of latent HIV-1 and on activation may be implicated in spreading the infection to other neighbouring cells, such as microglia or macrophages.
Assuntos
Astrócitos/virologia , Antígenos CD4/metabolismo , Infecções por HIV/virologia , HIV-1/fisiologia , Receptores de Quimiocinas/metabolismo , Receptores de HIV/metabolismo , Adulto , Sequência de Aminoácidos , Anticorpos Monoclonais/metabolismo , Astrócitos/citologia , Astrócitos/metabolismo , Sítios de Ligação , Encéfalo/citologia , Encéfalo/embriologia , Células Cultivadas , Quimiocina CCL2/metabolismo , Quimiocina CCL4 , Quimiocina CCL5/metabolismo , Quimiocina CXCL12 , Quimiocinas CXC/metabolismo , Criança , Expressão Gênica , Proteína gp120 do Envelope de HIV/genética , Proteína gp120 do Envelope de HIV/imunologia , HIV-1/crescimento & desenvolvimento , HIV-1/isolamento & purificação , HIV-1/metabolismo , Humanos , Lactente , Proteínas Inflamatórias de Macrófagos/metabolismo , Dados de Sequência Molecular , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/imunologia , Receptores CCR1 , Receptores CCR2 , Receptores CCR3 , Receptores CCR5/genética , Receptores CCR5/metabolismo , Receptores CXCR4/genética , Receptores CXCR4/metabolismo , Receptores de Quimiocinas/genética , Receptores de Citocinas/genética , Receptores de Citocinas/metabolismo , Receptores de HIV/genética , Ativação ViralRESUMO
In phage P4, transcription of the left operon may occur from both the constitutive PLE promoter and the regulated PLL promoter, about 400 nucleotides upstream of PLE. A strong Rho-dependent termination site, timm, is located downstream of both promoters. When P4 immunity is expressed, transcription starting at PLE is efficiently terminated at timm, whereas transcription from PLL is immunity insensitive and reads through timm. We report the identification of two nested genes, kil and eta, located in the P4 left operon. The P4 kil gene, which encodes a 65-amino-acid polypeptide, is the first translated gene downstream of the PLE promoter, and its expression is controlled by P4 immunity. Overexpression of kil causes cell killing. This gene is the terminal part of a longer open reading frame, eta, which begins upstream of PLE. The eta gene is expressed when transcription starts from the PLL promoter. Three likely start codons predict a size between 197 and 199 amino acids for the Eta gene product. Both kil and eta overlap the timm site. By cloning kil upstream of a tRNA reporter gene, we demonstrated that translation of the kil region prevents premature transcription termination at timm. This suggests that P4 immunity might negatively control kil translation, thus enabling transcription termination at timm. Transcription starting from PL proceeds through timm. Mutations that create nonsense codons in eta caused premature termination of transcription starting from PLL. Suppression of the nonsense mutation restored transcription readthrough at timm. Thus, termination of transcription from PLL is prevented by translation of eta.
Assuntos
Colífagos/genética , Regulação Viral da Expressão Gênica , Biossíntese de Proteínas , Transcrição Gênica , Proteínas Virais/biossíntese , Sequência de Aminoácidos , Sequência de Bases , DNA Viral , Escherichia coli/virologia , Genes Virais , Dados de Sequência Molecular , Mutagênese , Fases de Leitura Aberta , Homologia de Sequência de Aminoácidos , Proteínas Virais/genéticaRESUMO
In this study, the spectroscopic features and microscopical applications of the fluorescent daunomycin-Al3+ complex have been analyzed. In the presence of Al3+, the absorption spectrum of daunomycin showed a deep bathochromic shift and new peaks at 529 and 566 nm, whereas the fluorescence emission was considerably modified. The emission of daunomycin alone (peak at 560 nm under optimal excitation at 470 nm) decreased continuously from 0.5 to 24h after addition of Al3+ ions, and a new emission peak appeared at 580 nm (optimal excitation at 530 nm). Under the fluorescence microscope using green exciting light, nuclei from chicken blood smears and paraffin sections of rat embryos stained with daunomycin showed a weak emission, which greatly increased after treatment with Al3+ ions. The bright and stable fluorescence of chromatin DNA induced by daunomycin-Al3+ could be a valuable labelling method in fluorescence microscopy and DNA cytochemistry.
Assuntos
Compostos de Alumínio/química , Daunorrubicina/química , Microscopia de Fluorescência/métodos , Espectrometria de Fluorescência/métodos , Animais , Núcleo Celular/metabolismo , Núcleo Celular/ultraestrutura , Galinhas , Embrião de Mamíferos/química , Embrião não Mamífero , Feminino , Corantes Fluorescentes/química , Histocitoquímica , Masculino , Gravidez , Ratos , Ratos WistarRESUMO
OBJECTIVES: To investigate the correlation between the serum levels of the CC-chemokines RANTES, macrophage inflammatory protein (MIP)-1alpha and MIP-1beta, and the progression of HIV-1 disease. DESIGN: Retrospective analysis of serial serum samples from HIV-1 seroconverters selected according to clinical outcome. METHODS: Twenty-one patients, derived from a cohort recruited between 1985 and 1996 for a prospective study of the natural history of HIV infection, were analysed. All patients had at least one HIV-1-seronegative sample within 1 year prior to the first seropositive test and were followed longitudinally throughout the course of HIV-1 infection (mean follow-up, 73.5 months). Nine were rapid progressors (RP; patients who developed AIDS within 60 months of antibody seroconversion), seven were slow progressors (SP; patients who developed AIDS after 60 months), and five were long-term asymptomatic (LTA; patients with circulating CD4+ cells higher than 400 x 10(6)/l, no signs of HIV disease, no antiretroviral therapy for more than 96 months). A total of 339 serum samples was studied (mean, 16.1 per patient). The levels of RANTES, MIP-1alpha and MIP-1beta were measured by enzyme-linked immunosorbent assay and correlated with different immunological and clinical parameters. RESULTS: Over the entire follow-up period, the geometric mean of serum RANTES was significantly higher in RP [68.6 ng/ml; 95% confidence interval (CI), 56.9-82.7] than in SP (23.7 ng/ml; 95% CI, 20.0-28.2; P < 0.001) and LTA (19.5 ng/ml; 95% CI, 15.5-24.5; P < 0.001). This difference was already significant during the early clinical stages, when patients had peripheral blood CD4+ cell counts still greater than 400 x 10(6)/l (P < 0.001). By contrast, the mean serum levels of MIP-1alpha and MIP-1beta did not differ significantly between the three study groups. Multivariate analysis using the Cox proportional hazard model demonstrated that the mean serum concentration of RANTES before the development of AIDS was independently associated with the time to AIDS (relative risk, 4.5; 95% CI, 1.1-18.2; P = 0.035). In patients with low versus high mean serum RANTES before the fall of CD4+ cells below 400 x 10(6)/l, the median AIDS-free time was 117.5 and 42.7 months, respectively (P = 0.037). CONCLUSION: These data suggest that an elevation of serum RANTES predicts a rapid progression of the disease since the early stages of HIV-1 infection.
Assuntos
Quimiocina CCL5/sangue , Infecções por HIV/sangue , HIV-1 , Proteínas Inflamatórias de Macrófagos/sangue , Adulto , Quimiocina CCL3 , Quimiocina CCL4 , Feminino , Humanos , Estudos Longitudinais , Masculino , Estudos RetrospectivosRESUMO
The photosensitizing effects of liposomal zinc(II)-phthalocyanine (ZnPc) on HeLa cells, with emphasis on morphological changes and mechanisms for cell death, have been studied. No dark toxicity for ZnPc alone was found. Incubation for 1 h with ZnPc followed by red light irradiation induced a variable decrease in the surviving of cells, which was related to both drug concentration and irradiation time. A lethal photodynamic effect (100% of the cells are killed: LD100) was induced by 5 x 10-6 M ZnPc and 5-min irradiation, whereas a sublethal effect (60% of the cells are killed: LD60) was detected with 10 7 M ZnPc and 3 min of red light. Toluidine blue and Hoechst 33258 staining showed characteristic alterations of cell morphology. Numerous bubbles on the plasma membrane were found immediately after an LD100 treatment, and a necrotic morphology appeared 24 h later. On the contrary, severe cell shrinkage with nuclear fragmentation. characteristic of apoptosis. was observed 8 and 24 h after LD60 treatments. In this case, propidium iodide-acridine orange labeling and the TUNEL assay confirmed the occurrence of apoptosis. The highest amount of apoptotic cells appeared 24 h after LD60 treatments, particularly in detached cells, as revealed by cell counting and DNA electrophoresis. Both apoptotic and necrotic mechanisms for cell death occur in HeLa cells in dependence on the experimental protocol of ZnPc photodynamic treatments.
Assuntos
Indóis/farmacologia , Compostos Organometálicos/farmacologia , Fotoquimioterapia/métodos , Fármacos Fotossensibilizantes/farmacologia , Apoptose , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos da radiação , Relação Dose-Resposta a Droga , Eletroforese em Gel de Ágar , Células HeLa , Humanos , Isoindóis , Cinética , Luz , Lipossomos , Microscopia de Fluorescência , Necrose , Fatores de Tempo , Células Tumorais Cultivadas , Compostos de ZincoRESUMO
The identification of HIV-1 coreceptors has provided a molecular basis for the tropism of different HIV-1 strains. CXC chemokine receptor-4 (CXCR4) mediates the entry of both primary and T cell line-adapted (TCLA) syncytia-inducing strains. Although macrophages (M phi) express CXCR4, this coreceptor is assumed to be nonfunctional for HIV-1 infection. We addressed this apparent paradox by infecting human monocyte-derived M phi with primary and TCLA isolates that were rigorously characterized for coreceptor usage and by adding the natural CXCR4 ligand, stem cell differentiation factor-1, to specifically block CXCR4-mediated entry. Our results show that primary HIV-1 isolates that selectively use CXCR4 productively infected both normal and C-C chemokine receptor-5-null M phi. By contrast, M phi supported the entry of CXCR4-dependent TCLA strains with variable efficiency but were not productively infected. Thus, the tropism of HIV isolates results from complex virus/host cell interactions both at the entry and postentry levels.