RESUMO
BACKGROUND: The addition of carbogen and nicotinamide (CON) to radiotherapy (RT) improves overall survival in invasive bladder cancer. We explored whether expression of the hypoxia marker hypoxia-inducible factor-1α (HIF-1α) alone or in combination with other markers predicted benefit from CON. METHODS: A retrospective study was carried out using material from patients with high-grade invasive bladder carcinoma enrolled in the BCON phase III trial of RT alone or with CON (RT+CON). HIF-1α expression was studied in 137 tumours using tissue microarrays and immunohistochemistry. Data were available from other studies for carbonic anhydrase IX and glucose transporter 1 protein and gene expression and tumour necrosis. RESULTS: Patients with high HIF-1α expression had improved 5-year local relapse-free survival with RT+CON (47%) compared with RT alone (21%; hazard ratio (HR) 0.48, 95% CI 0.26-0.8, P=0.02), no benefit was seen with low HIF-1α expression (HR 0.81, 95% CI 0.43-1.50, P=0.5). Combinations of markers including necrosis also predicted benefit but did not improve on prediction using necrosis alone. CONCLUSIONS: HIF-1α may be used to predict benefit from CON in patients with bladder cancer but does not improve on use of necrosis.
Assuntos
Biomarcadores Tumorais/metabolismo , Carcinoma de Células de Transição/metabolismo , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Neoplasias da Bexiga Urinária/metabolismo , Idoso , Carcinoma de Células de Transição/mortalidade , Carcinoma de Células de Transição/terapia , Hipóxia Celular , Quimiorradioterapia , Intervalo Livre de Doença , Feminino , Humanos , Estimativa de Kaplan-Meier , Masculino , Invasividade Neoplásica , Modelos de Riscos Proporcionais , Estudos Retrospectivos , Resultado do Tratamento , Neoplasias da Bexiga Urinária/mortalidade , Neoplasias da Bexiga Urinária/terapiaRESUMO
Epithelial to mesenchymal transition (EMT) promotes tumor progression and invasion. As no study has focused on gastroesophageal junction (GEJ) tumors, the expression of three EMT-related proteins (S100A4, vimentin, and Snail1) was investigated with the aim of assessing their pathologic and prognostic significance. Resection specimens were obtained from 104 patients who underwent surgery for GEJ adenocarcinoma, without preoperative chemotherapy. Three tissue cores were obtained from each of the tumor body (TB), luminal surface (LS), and invasive edge (IE) to produce tissue microarrays, and immunohistochemical staining was performed. The microarrays were scored independently by two observers. The demographic and histopathologic details of the patients were collected. Overall positive expression was observed in 88 (S100A4, 85%), 16 (vimentin, 14%), and 92 (Snail1, 89%) tumors. Staining for S100 A4 was positive in 79 (76%) of TB, 69 (66%) of IE, and 69 (66%) of LS specimens. Staining for vimentin was positive in 7 (6%) of TB, 11 (11%) of IE, and 5 (5%) of LS specimens. Staining for Snail1 was positive in 83 (80%) of TB, 51 (49%) of IE, and 78 (75%) of LS specimens. Positive staining of TB for S100A4 (P = 0.04) and Snail1 at IE (P = 0.01) was associated with involvement of circumferential resection margins. Positive staining for S100A4 in the TB (P = 0.02) and LS (P = 0.01) was associated with poor 5-year overall survival. Vimentin had no statistically significant relationships with pathologic factors or outcome. The acquisition of mesenchymal protein S100A4 is associated with a poor prognosis in patients with GEJ tumors who undergo potentially curative surgery, and LS samples can be used to obtain prognostic information. Increased EMT-related protein expression (S100A4, Snail1) is associated with the involvement of circumferential resection margin.
Assuntos
Neoplasias Esofágicas/metabolismo , Junção Esofagogástrica/patologia , Proteínas S100/metabolismo , Fatores de Transcrição/metabolismo , Vimentina/metabolismo , Adenocarcinoma/metabolismo , Adenocarcinoma/mortalidade , Adenocarcinoma/patologia , Idoso , Biomarcadores Tumorais/metabolismo , Transição Epitelial-Mesenquimal , Neoplasias Esofágicas/mortalidade , Neoplasias Esofágicas/patologia , Feminino , Humanos , Masculino , Prognóstico , Proteína A4 de Ligação a Cálcio da Família S100 , Fatores de Transcrição da Família Snail , Coloração e RotulagemRESUMO
BACKGROUND: Tissue factor (TF), which has a role in normal tissue haemostasis, was reported to be aberrantly expressed, associated with higher microvascular density and a poor prognosis in intestinal-type gastric adenocarcinoma in the Japanese population. This is the first study to look at the relationship of TF and the metaplasia-adenoma-carcinoma sequence (MACS) of gastric cancer in a European population. METHODS: The expression of TF was examined immunohistochemically in 191 gastric tissue samples: (13: normal; 18: intestinal metaplasia; 160: gastric adenocarcinoma) from the European population. RESULTS: TF was not expressed in normal gastric mucosal cells. A strong intensity of staining was found in intestinal metaplasia cells but in 2 of 18 samples. TF expression increased with advancing stage of gastric cancer (P<0.0001, Jonckheere's test for ordered medians). Stage 3-4 gastric cancers preferentially expressed TF (34%, P=0.04). In comparison with the Japanese study, TF was not expressed at a higher level in intestinal vs diffuse-type gastric cancers and expression had 'no prognostic' significance. CONCLUSION: TF may be involved in tumour progression along the MACS of gastric cancer in the European population and is shown to start in precancerous lesions. However, clinical features may differ due to differences in biological features in the two populations, as reflected by differences in TF expression profile.
Assuntos
Adenoma/metabolismo , Carcinoma/metabolismo , Neoplasias Gástricas/metabolismo , Estômago/patologia , Tromboplastina/biossíntese , Adenocarcinoma/genética , Adenocarcinoma/metabolismo , Adenocarcinoma/patologia , Adenoma/genética , Adenoma/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma/genética , Carcinoma/patologia , Progressão da Doença , Feminino , Mucosa Gástrica/metabolismo , Humanos , Imuno-Histoquímica , Masculino , Metaplasia/genética , Metaplasia/metabolismo , Pessoa de Meia-Idade , Prognóstico , Neoplasias Gástricas/genética , Neoplasias Gástricas/patologia , Tromboplastina/genética , Tromboplastina/metabolismo , População BrancaRESUMO
BACKGROUND: The transcription factor FOXM1 is an important regulator of the cell cycle through controlling periodic gene expression during the G2 and M phases. One key target for FOXM1 is the gene encoding the protein kinase PLK1 and PLK1 itself acts in a positive feedback loop to phosphorylate and activate FOXM1. Both FOXM1 and PLK1 have been shown to be overexpressed in a variety of different tumour types. METHODS: We have used a combination of RT-PCR, western blotting, tissue microarrays and metadata analysis of microarray data to study whether the FOXM1-PLK1 regulatory axis is upregulated and operational in oesophageal adenocarcinoma. RESULTS: FOXM1 and PLK1 are expressed in oesophageal adenocarcinoma-derived cell lines and demonstrate cross-regulatory interactions. Importantly, we also demonstrate the concomitant overexpression of FOXM1 and PLK1 in a large proportion of oesophageal adenocarcinoma samples. This co-association was extended to the additional FOXM1 target genes CCNB1, AURKB and CKS1. In a cohort of patients who subsequently underwent surgery, the expression of several FOXM1 target genes was prognostic for overall survival. CONCLUSIONS: FOXM1 and its target gene PLK1 are commonly overexpressed in oesophageal adenocarcinomas and this association can be extended to other FOXM1 target genes, providing potentially important biomarkers for predicting post-surgery disease survival.
Assuntos
Adenocarcinoma/genética , Proteínas de Ciclo Celular/genética , Neoplasias Esofágicas/genética , Fatores de Transcrição Forkhead/genética , Proteínas Serina-Treonina Quinases/genética , Proteínas Proto-Oncogênicas/genética , Adenocarcinoma/metabolismo , Proteínas de Ciclo Celular/biossíntese , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular Tumoral , Estudos de Coortes , Neoplasias Esofágicas/metabolismo , Proteína Forkhead Box M1 , Fatores de Transcrição Forkhead/biossíntese , Fatores de Transcrição Forkhead/metabolismo , Regulação Neoplásica da Expressão Gênica , Humanos , Prognóstico , Proteínas Serina-Treonina Quinases/biossíntese , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Proto-Oncogênicas/biossíntese , Proteínas Proto-Oncogênicas/metabolismo , Regulação para Cima , Quinase 1 Polo-LikeRESUMO
BACKGROUND: As degradation of formalin-fixed paraffin-embedded (FFPE) samples limits the ability to profile mRNA expression, we explored factors predicting the success of mRNA expression profiling of FFPE material and investigated an approach to overcome the limitation. METHODS: Bladder (n=140, stored 3-8 years) and cervix (n=160, stored 8-23 years) carcinoma FFPE samples were hybridised to Affymetrix Exon 1.0ST arrays. Percentage detection above background (%DABG) measured technical success. Biological signal was assessed by distinguishing cervix squamous cell carcinoma (SCC) and adenocarcinoma (AC) using a gene signature. As miR-205 had been identified as a marker of SCC, precursor mir-205 was measured by Exon array and mature miR-205 by qRT-PCR. Genome-wide microRNA (miRNA) expression (Affymetrix miRNA v2.0 arrays) was compared in eight newer FFPE samples with biological signal and eight older samples without. RESULTS: RNA quality controls (QCs) (e.g., RNA integrity (RIN) number) failed to predict profiling success, but sample age correlated with %DABG in bladder (R=-0.30, P<0.01) and cervix (R=-0.69, P<0.01). Biological signal was lost in older samples and neither a signature nor precursor mir-205 separated samples by histology. miR-205 qRT-PCR discriminated SCC from AC, validated by miRNA profiling (26-fold higher in SCC; P=1.10 × 10(-5)). Genome-wide miRNA (R=0.95) and small nucleolar RNA (R=0.97) expression correlated well in the eight newer vs older FFPE samples and better than mRNA expression (R=0.72). CONCLUSION: Sample age is the best predictor of successful mRNA profiling of FFPE material, and miRNA profiling overcomes the limitation of age and copes well with older samples.
Assuntos
Perfilação da Expressão Gênica/métodos , MicroRNAs/metabolismo , Inclusão em Parafina/métodos , Estabilidade de RNA , RNA Mensageiro/metabolismo , Neoplasias da Bexiga Urinária/genética , Neoplasias do Colo do Útero/genética , Adenocarcinoma/genética , Carcinoma de Células Escamosas/genética , Feminino , Fixadores/farmacologia , Formaldeído/farmacologia , Regulação Neoplásica da Expressão Gênica , Humanos , Masculino , Fatores de Tempo , Preservação de TecidoRESUMO
BACKGROUND: Degradation and chemical modification of RNA in formalin-fixed paraffin-embedded (FFPE) samples hamper their use in expression profiling studies. This study aimed to show that useful information can be obtained by Exon-array profiling archival FFPE tumour samples. METHODS: Nineteen cervical squamous cell carcinoma (SCC) and 9 adenocarcinoma (AC) FFPE samples (10-16-year-old) were profiled using Affymetrix Exon arrays. The gene signature derived was tested on a fresh-frozen non-small cell lung cancer (NSCLC) series. Exploration of biological networks involved gene set enrichment analysis (GSEA). Differential gene expression was confirmed using Quantigene, a multiplex bead-based alternative to qRT-PCR. RESULTS: In all, 1062 genes were higher in SCC vs AC, and 155 genes higher in AC. The 1217-gene signature correctly separated 58 NSCLC into SCC and AC. A gene network centered on hepatic nuclear factor and GATA6 was identified in AC, suggesting a role in glandular cell differentiation of the cervix. Quantigene analysis of the top 26 differentially expressed genes correctly partitioned cervix samples as SCC or AC. CONCLUSION: FFPE samples can be profiled using Exon arrays to derive gene expression signatures that are sufficiently robust to be applied to independent data sets, identify novel biology and design assays for independent platform validation.
Assuntos
Éxons , Perfilação da Expressão Gênica , Análise em Microsséries/métodos , Neoplasias/genética , Neoplasias/patologia , Preservação de Tecido/métodos , Adenocarcinoma/genética , Adenocarcinoma/patologia , Biópsia , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/patologia , Carcinoma de Células Escamosas/classificação , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/patologia , Feminino , Fixadores/farmacologia , Formaldeído/farmacologia , Humanos , Inclusão em Parafina/métodos , Fatores de Tempo , Fixação de Tecidos/métodos , Neoplasias do Colo do Útero/classificação , Neoplasias do Colo do Útero/genética , Neoplasias do Colo do Útero/patologiaRESUMO
We show that the nonimmunosuppressive analogues of the immunosuppressive drugs FK506, rapamycin and cyclosporin A promote neurite outgrowth both in PC12 cells and sensory neuronal cultures of dorsal root ganglia with potencies resembling their immunosuppressive homologues. Neurotrophic potencies of the immunophilin ligands resemble their potencies in binding to and inhibiting the rotamase activity of FKBP-12 of cyclophilin. Since nonimmunosuppressive immunophilin ligands, which are devoid of calcineurin inhibitory activity, are equally neurotrophic, inhibition of calcineurin activity is not the mediator of the neurotrophic effects. The immunophilin ligands are neurotrophic in intact animals. FK506 and L-685,818 (the C18-hydroxy, C21-ethyl derivative of FK506) treatment of rats with crushed sciatic nerves enhances both functional and morphologic recovery. The striking potency of these agents, their bioavailability and the dissociation of neurotrophic from immunosuppressant actions argue for their therapeutic relevance in the treatment of neurodegenerative diseases.
Assuntos
Ciclosporinas/farmacologia , Imunossupressores/farmacologia , Neurônios/efeitos dos fármacos , Piperidinas/farmacologia , Piridazinas/farmacologia , Tacrolimo/análogos & derivados , Animais , Células Cultivadas , Embrião de Galinha , Ciclosporina/farmacologia , Gânglios Espinais/citologia , Regeneração Nervosa/efeitos dos fármacos , Neuritos/efeitos dos fármacos , Neurônios Aferentes/citologia , Células PC12 , Polienos/farmacologia , Ratos , Nervo Isquiático/efeitos dos fármacos , Sirolimo , Tacrolimo/farmacologiaRESUMO
BACKGROUND: Members of the HMGN protein family modulate chromatin structure and influence epigenetic modifications. HMGN1 and HMGN2 are highly expressed during early development and in the neural stem/progenitor cells of the developing and adult brain. Here, we investigate whether HMGN proteins contribute to the chromatin plasticity and epigenetic regulation that is essential for maintaining pluripotency in stem cells. RESULTS: We show that loss of Hmgn1 or Hmgn2 in pluripotent embryonal carcinoma cells leads to increased levels of spontaneous neuronal differentiation. This is accompanied by the loss of pluripotency markers Nanog and Ssea1, and increased expression of the pro-neural transcription factors Neurog1 and Ascl1. Neural stem cells derived from these Hmgn-knockout lines also show increased spontaneous neuronal differentiation and Neurog1 expression. The loss of HMGN2 leads to a global reduction in H3K9 acetylation, and disrupts the profile of H3K4me3, H3K9ac, H3K27ac and H3K122ac at the Nanog and Oct4 loci. At endodermal/mesodermal genes, Hmgn2-knockout cells show a switch from a bivalent to a repressive chromatin configuration. However, at neuronal lineage genes whose expression is increased, no epigenetic changes are observed and their bivalent states are retained following the loss of HMGN2. CONCLUSIONS: We conclude that HMGN1 and HMGN2 maintain the identity of pluripotent embryonal carcinoma cells by optimising the pluripotency transcription factor network and protecting the cells from precocious differentiation. Our evidence suggests that HMGN2 regulates active and bivalent genes by promoting an epigenetic landscape of active histone modifications at promoters and enhancers.
Assuntos
Cromatina/metabolismo , Proteína HMGN2/metabolismo , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/química , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Diferenciação Celular , Linhagem Celular Tumoral , Autorrenovação Celular , Proteína HMGN1/genética , Proteína HMGN1/metabolismo , Proteína HMGN2/genética , Histonas/metabolismo , Camundongos , Proteína Homeobox Nanog/genética , Proteína Homeobox Nanog/metabolismo , Proteínas do Tecido Nervoso/química , Proteínas do Tecido Nervoso/metabolismo , Células-Tronco Neurais/citologia , Células-Tronco Neurais/metabolismo , Neurônios/citologia , Neurônios/metabolismo , Fator 3 de Transcrição de Octâmero/metabolismo , Células-Tronco Pluripotentes/citologia , Células-Tronco Pluripotentes/metabolismo , Processamento de Proteína Pós-TraducionalRESUMO
BACKGROUND: Gastric cancers present late in life with advanced disease and carry a poor prognosis. Polo-like Kinase 1 (PLK1) is a mitotic kinase with regulatory functions during G2/M and mitosis in the cell cycle. In mammalian cells, there is an intricate co-regulatory relationship between PLK1 and the forkhead transcription factor FOXM1. It has been demonstrated that individually either PLK1 or FOXM1 expression predicts poorer survival. However, the co-expression of both of these markers in gastric adenocarcinomas has not been reported previously. METHODS: We aimed to assess the expression of PLK1 and FOXM1 in Gastric adenocarcinomas in a Western Population, to examine whether there is a relationship of PLK1 to FOXM1 in cancer samples. We assess both the protein and mRNA expression in this patient population by Tissue Microarray immunohistochemistry and RT-PCR. RESULTS: Immunohistochemistry was performed on biopsy samples from 79 patients with gastric cancer. Paired normal controls were available in 47 patients. FOXM1 expression was significantly associated with gastric adenocarcinoma (p = 0.001). PLK1 and FOXM1 co-expression was demonstrated in 6/8 (75 %) tumours when analysed by RT-PCR. FOXM1 is overexpressed in a large proportion of gastric carcinomas at the protein level and FOXM1 and PLK1 are concomitantly overexpressed at the mRNA level in this cancer type. CONCLUSIONS: This study has demonstrated that FOXM1 and its target gene PLK1 are coordinately overexpressed in a proportion of gastric adenocarcinomas. This suggests that chemotherapeutic treatments that target this pathway may be of clinical utility.
Assuntos
Adenocarcinoma/metabolismo , Proteínas de Ciclo Celular/metabolismo , Fatores de Transcrição Forkhead/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Neoplasias Gástricas/metabolismo , Adenocarcinoma/enzimologia , Adenocarcinoma/patologia , Idoso , Proteínas de Ciclo Celular/genética , Feminino , Proteína Forkhead Box M1 , Fatores de Transcrição Forkhead/genética , Humanos , Masculino , Pessoa de Meia-Idade , Proteínas Serina-Treonina Quinases/genética , Proteínas Proto-Oncogênicas/genética , RNA Mensageiro/genética , Neoplasias Gástricas/enzimologia , Neoplasias Gástricas/patologia , Quinase 1 Polo-LikeRESUMO
PURPOSE: To study the relationship between pretreatment peripheral blood lymphocyte radiosensitivity and morbidity following radiation therapy. METHODS AND MATERIALS: A prospective study was carried out in which patients with carcinoma of the cervix underwent radiation therapy. Intrinsic radiosensitivity was measured on pretreatment peripheral blood lymphocytes, using a limiting dilution clonogenic assay. Late morbidity was assessed using the Franco-Italian glossary. Results were correlated in an actuarial analysis. RESULTS: There were no correlations between the measured lymphocyte radiosensitivity (SF2) and colony-forming efficiency, patient age, tumor grade, or disease stage. For 83 patients, lymphocyte SF2 was a significant prognostic factor for the probability of developing both any (p = 0.002) and Grade 3 (p = 0.026) morbidity. In 174 patients, stage showed borderline significance as a prognostic factor for morbidity (p = 0.056). However, the type of treatment (intracavitary alone, intracavitary plus parametrial irradiation, single insertion plus whole-pelvis irradiation) was significantly associated with the probability of developing late complications (p = 0.013). There was a weak significant inverse correlation between lymphocyte SF2 and grade of morbidity (r = -0.34, p = 0.002). CONCLUSION: These data highlight the importance of normal cell radiosensitivity as a factor determining radiation therapy response. They also show that peripheral blood lymphocyte SF2 is a highly significant prognostic factor for the probability of developing late radiation morbidity, and that carcinoma of the cervix is a good model for testing radiobiologic principles in the clinic.
Assuntos
Carcinoma/radioterapia , Linfócitos/efeitos da radiação , Lesões por Radiação/etiologia , Tolerância a Radiação , Neoplasias do Colo do Útero/radioterapia , Fatores Etários , Braquiterapia/efeitos adversos , Carcinoma/sangue , Carcinoma/patologia , Sobrevivência Celular/efeitos da radiação , Ensaio de Unidades Formadoras de Colônias , Feminino , Humanos , Linfócitos/fisiologia , Estadiamento de Neoplasias , Probabilidade , Prognóstico , Estudos Prospectivos , Neoplasias do Colo do Útero/sangue , Neoplasias do Colo do Útero/patologiaRESUMO
A series of pseudopeptides containing alkyl-, cycloalkyl-, aryl-, and aralkyl-substituted 1,3,8-triazaspiro[4.5]decan-4-one-3-acetic acids as amino acid surrogates to replace the Pro2-Pro3-Gly4-Phe5 section of the peptide bradykinin B2 receptor antagonist [Pro3, Phe5]HOE 140 (D-Arg0-Arg1-Pro2-Pro3-Gly4-Phe5-Ser6-D-Tic7+ ++-Oic8-Arg9) were prepared. These psuedopeptides were examined in vitro for their B2 receptor affinities as well as for their ability to block bradykinin mediated actions in vivo. Two compounds in particular, NPC 18521 (I) and NPC 18688 (V) were quite potent in these latter assays, indicating that a significant portion of this prototypical second generation decapeptide antagonist can be replaced with a more compact nonpeptide molecule.
Assuntos
Antagonistas dos Receptores da Bradicinina , Imidazóis/síntese química , Compostos de Espiro/síntese química , Sequência de Aminoácidos , Animais , Ligação Competitiva , Pressão Sanguínea/efeitos dos fármacos , Bradicinina/antagonistas & inibidores , Células CHO , Membrana Celular/efeitos dos fármacos , Cricetinae , Imidazóis/química , Imidazóis/metabolismo , Imidazóis/farmacologia , Dados de Sequência Molecular , Estrutura Molecular , Oligopeptídeos/metabolismo , Coelhos , Ratos , Ratos Sprague-Dawley , Receptor B2 da Bradicinina , Compostos de Espiro/química , Compostos de Espiro/metabolismo , Compostos de Espiro/farmacologia , Relação Estrutura-AtividadeRESUMO
BACKGROUND AND PURPOSE: RH1 is a new bioreductive agent that was developed as a cytotoxic agent with selectivity for tumour cells expressing high levels of the enzyme DT-diaphorase (DTD). The aim of the present study was to investigate the cytotoxicity of RH1 in relation to cellular levels of reducing enzymes and any interaction of RH1 with ionizing radiation under oxic and hypoxic conditions. PATIENTS AND METHODS: The MB-MDA231 human breast cancer cell line (WT) and WT cells transfected with the NQO1 gene encoding DTD (the D7 cell line) were used to examine the dependency of RH1's cytotoxicity on cellular DTD activity. The role of the 1-electron reducing enzyme P450 reductase was also studied using a P450 reductase-transfected isogenic cell line (R4). A clonogenic assay was used to investigate the cytotoxicity of RH1 with and without irradiation in air and in nitrogen. In all cases drug exposure was for 3 h. RESULTS: DTD levels were around 300-fold higher in D7 compared to WT and R4 cells. RH1 was cytotoxic at nanomolar concentrations to all the cell lines, and was 2-3 times more toxic in the D7 cells with high DTD than in the other two cell lines. Doses of RH1 was around 2-fold more effective in hypoxic than in oxic WT cells, but not by as much in D7 cells. RH1 did not radiosensitise the cells but showed an additive effect when combined with irradiation under oxic and hypoxic conditions. CONCLUSIONS: RH1 shows high clonogenic cytotoxicity to MDA231 cells with high DTD activity but its selectivity based on the presence of DTD is much less than as shown in previous reports. RH1 showed an additive cell killing effect when combined with irradiation under both oxic and hypoxic conditions.
Assuntos
Antineoplásicos/farmacologia , Aziridinas/farmacologia , Benzoquinonas/farmacologia , Neoplasias Mamárias Experimentais/patologia , Neoplasias Mamárias Experimentais/radioterapia , Radiossensibilizantes/farmacologia , Linhagem Celular Tumoral/efeitos dos fármacos , Linhagem Celular Tumoral/efeitos da radiação , Avaliação Pré-Clínica de Medicamentos , Humanos , Neoplasias Mamárias Experimentais/enzimologia , NAD(P)H Desidrogenase (Quinona)/metabolismo , NADPH-Ferri-Hemoproteína Redutase/metabolismo , Transfecção , Ensaio Tumoral de Célula-TroncoRESUMO
The effects of incremental dose infusions of nitroglycerin, 10-160 micrograms/min, on pulmonary capillary wedge pressure and other haemodynamic variables have been studied in patients with left ventricular failure. Intravenous (IV) nitroglycerin caused a dose-related improvement in myocardial performance, with significant reductions in the raised pulmonary capillary wedge pressure and systemic vascular resistance. At the lowest dose of infusion only the venodilator action of nitroglycerin was apparent. From 40-160 micrograms/min the associated arteriolar dilatation was associated with a consistent improvement in myocardial performance.
Assuntos
Insuficiência Cardíaca/fisiopatologia , Hemodinâmica/efeitos dos fármacos , Nitroglicerina/administração & dosagem , Idoso , Feminino , Insuficiência Cardíaca/tratamento farmacológico , Ventrículos do Coração/fisiopatologia , Humanos , Infusões Parenterais , Masculino , Pessoa de Meia-IdadeRESUMO
Carbon disulfide is a neurotoxic compound used in the production of viscose rayon, and is a major decomposition product of dithiocarbamates used in industry, agriculture, and medicine. Methods used currently for assessing exposure to CS2 are limited in their ability to evaluate cumulative exposures and provide useful information for relatively short periods of time after exposure has ended. The present investigation evaluates a method for monitoring CS2 exposure that consists of cleaving the thiocarbonyl function of free CS2 or certain CS2-generated modifications on proteins using toluene-3,4-dithiol. The resulting toluene trithiocarbonate product is then quantified using reverse-phase high-performance liquid chromatography. The sensitivity, dose response, kinetics and specificity of this biomarker in blood were examined in rats administered CS2 by inhalation, intraperitoneal injection, or gavage for acute through subchronic periods. Dithiol reactive functions in plasma and hemolysate demonstrated a linear dose response over a wide range of exposure levels, were dependent upon the duration of exposure, and appeared to have an appropriate sensitivity for evaluating occupational levels of exposure. Elimination rates of dithiol reactive functions may also be dependent upon exposure duration and exhibit different kinetics for plasma and hemolysate suggesting that elimination rates may be useful for estimating cumulative exposure and intervals between exposure and sample procurement. Dithiol analysis, used in conjunction with previously established erythrocyte protein cross-linking biomarkers, may provide a means to characterize the internal dose of CS2 resulting from acute through chronic periods, and may provide insight into the level of CS2-mediated covalent protein modifications occurring within the nervous system.
Assuntos
Dissulfeto de Carbono/metabolismo , Tionas/sangue , Tolueno/análogos & derivados , Animais , Biomarcadores , Cromatografia Líquida de Alta Pressão , Relação Dose-Resposta a Droga , Feminino , Masculino , Ratos , Ratos Endogâmicos F344 , Ratos Sprague-Dawley , Sensibilidade e Especificidade , Fatores de Tempo , Tolueno/sangueRESUMO
Differences in the toxicities observed for dithiocarbamates have been proposed to result from the influence of nitrogen substitution, oxidation state, and route of exposure. To better characterize the fate of dithiocarbmates in vivoas a function of structure and route of exposure, rats were administered equimolar doses of carbon disulfide (CS2), N-methyldithiocarbamate, pyrrolidine dithiocarbamate, N,N-diethyldithiocarbamate, or disulfiram daily for five days, either po or ip, and sequential blood samples obtained. Protein dithiocarbamates formed by the in vivo release of CS2, parent dithiocarbamate, and protein-bound mixed disulfides were assessed in plasma and hemolysate by measuring toluene trithiocarbonate generated upon treatment with toluene-3, 4-dithiol (TdT). To aid in determining the bioavailability of CS2 from the administered dithiocarbamates, the urinary CS2 metabolites, 2-thiothiazolidine-4-carboxylic acid (TTCA) and 2-thiothiazolidin-4-ylcarbonylglycine (TTCG), were also determined. The levels of TdT-reactive moieties detected depended upon both the compound administered and the route of exposure. Parent dithiocarbamates, with the exception of disulfiram, were eliminated from blood within 24 h; but protein associated TdT-reactive moieties persisted and accumulated with repeated exposure, regardless of the route of exposure. N-Methyldithiocarbamate demonstrated the greatest potential to produce intracellular globin modifications, presumably through its unique ability to generate a methylisothiocyanate metabolite. Urinary excretion of TTCA and TTCG was more sensitive than TdT analysis for detecting dithiocarbamate exposure, but TdT analysis appeared to be a better indicator of in vivo release of CS2 by dithiocarbamates than were urinary CS2 metabolites. These data suggest that CS2 is a more important metabolite, following oral exposure, than are other routes of exposure, e.g., inhalation or dermal. In addition, data also suggest that acid stability, nitrogen substitution, and route of exposure are important factors governing the toxicity observed for a particular dithiocarbamate.
Assuntos
Dissulfeto de Carbono/metabolismo , Tiocarbamatos/química , Tolueno , Tolueno/análogos & derivados , Administração Oral , Animais , Cromatografia Líquida de Alta Pressão , Injeções Intraperitoneais , Masculino , Proteínas/metabolismo , Ratos , Ratos Sprague-Dawley , Relação Estrutura-Atividade , Tiocarbamatos/sangue , Tiocarbamatos/urina , Distribuição Tecidual , Tolueno/sangue , Tolueno/metabolismo , Tolueno/urinaRESUMO
The technical aspects of orthotopic cardiac transplantation for univentricular heart in a 22-year-old man are discussed. Abnormal pulmonary artery anatomy resulted in right ventricular failure, which was successfully treated.
Assuntos
Ventrículos do Coração/transplante , Adulto , Anastomose Cirúrgica/métodos , Átrios do Coração/cirurgia , Ventrículos do Coração/anormalidades , Humanos , Masculino , PrognósticoRESUMO
The stable adenosine agonist [3H]cyclohexyladenosine binds to membranes prepared from guinea pig myenteric plexus with high affinity (Kd = 1.8 nM) in a saturable, reversible manner. Binding pharmacology was consistent with the labelling of an A1 type adenosine receptor with the R-isomer of N6-phenylisopropyladenosine (PIA) being 11 times more potent than the S-diastereomer. Binding was similar to that observed in brain tissue being displaced by a number of xanthine adenosine antagonists. In terms of density of binding sites, however, there were approximately 9 times fewer higher affinity binding sites in ileal membranes than in the central nervous system.
Assuntos
Adenosina/análogos & derivados , Córtex Cerebral/metabolismo , Plexo Mientérico/metabolismo , Receptores de Superfície Celular/metabolismo , Adenosina/metabolismo , Animais , Ligação Competitiva , Cobaias , Técnicas In Vitro , Membranas/metabolismo , Fenilisopropiladenosina/metabolismo , Ensaio Radioligante , Receptores de Superfície Celular/análise , Receptores Purinérgicos , Especificidade da Espécie , Xantinas/metabolismoRESUMO
Toxins from the venom of the African green mamba, Dendroaspis angusticeps, fulfill a major need for selective ligands for some of the five genetically defined subtypes of muscarinic acetylcholine receptors (m1-m5). Two toxins have been found that are highly selective antagonists for m1 and m4 receptors (m1-toxin and m4-toxin, respectively). Two other toxins (MT1 and MT2) bind with high affinity to both m1 and m4 receptors, and are agonists. Components of the venom also modify the binding of radiolabeled antagonists to m2 receptors, but an m2-selective toxin has not yet been isolated, m1-Toxin can bind to m1 receptors at the same time as typical competitive antagonists, suggesting that this toxin binds to the N-terminal and outer loops of m1 receptor molecules, rather than within the receptor pocket where typical agonists and antagonists bind. The binding of toxins to the outer parts of receptor molecules probably accounts for their much higher specificity for individual receptor subtypes than is seen with smaller ligands. Toxins are useful for identifying, counting, localizing, activating and blocking m1 and m4 receptors with high specificity.
Assuntos
Venenos Elapídicos/farmacologia , Antagonistas Muscarínicos/farmacologia , Neurotoxinas/farmacologia , Regulação Alostérica , Sequência de Aminoácidos , Animais , Células CHO , Cromatografia em Gel , Cromatografia por Troca Iônica , Cricetinae , Venenos Elapídicos/isolamento & purificação , Venenos Elapídicos/metabolismo , Elapidae , Dados de Sequência Molecular , Antagonistas Muscarínicos/isolamento & purificação , Antagonistas Muscarínicos/metabolismo , Neurotoxinas/isolamento & purificação , Neurotoxinas/metabolismo , Estrutura Secundária de Proteína , Receptor Muscarínico M1 , Receptores Muscarínicos/efeitos dos fármacos , Receptores Muscarínicos/metabolismoRESUMO
The venom of the Eastern green mamba from Africa, Dendroaspis angusticeps, contains a number of toxins which block the binding of 3H-antagonists to genetically-defined m1 and m4 muscarinic acetylcholine receptors. Most of the anti-muscarinic activity of the venom is due to the presence of a newly-isolated toxin, "m1-toxin", which has 64 amino acids and a molecular mass of 7361 Daltons. At present m1-toxin is the only ligand which is known to be capable of fully blocking m1 receptors without affecting m2-m5 receptors. It binds very rapidly, specifically and pseudoirreversibly to the extracellular face of m1 receptors on cells, in membranes or in solution, whether or not the primary receptor site is occupied by an antagonist. Bound toxin can either prevent the binding and action of agonists or antagonists, or prevent the dissociation of antagonists. The toxin is useful for identifying m1 receptors during anatomical and functional studies, for recognizing and stabilizing receptor complexes, and for occluding m1 receptors so that other receptors are more readily studied.
Assuntos
Venenos Elapídicos/química , Venenos Elapídicos/farmacologia , Antagonistas Muscarínicos , Neurotoxinas/química , Neurotoxinas/farmacologia , Acetilcolina , Animais , Células CHO , Cricetinae , Venenos Elapídicos/isolamento & purificação , Ligantes , Neurotoxinas/isolamento & purificaçãoRESUMO
PURPOSE: To examine whether in vitro measurements of normal and tumour cell radiosensitivity can be used as prognostic factors in clinical oncology. MATERIALS AND METHODS: Stage I-III cervix carcinoma patients were treated with radical radiotherapy with a minimum of 3 years' follow-up. Lymphocyte and tumour radiosensitivities were assayed using, respectively, a limiting dilution and soft agar clonogenic assay to obtain surviving fraction at 2 Gy (SF2). The results were related, in an actuarial analysis, to late morbidity assessed using the Franco Italian glossary. RESULTS: Patients with radiosensitive lymphocytes had a significantly increased risk of developing late complications (n = 93, p = 0.002). Increasing tumour radiosensitivity was associated with an increased risk of morbidity (n= 113, p=0.032). A significant correlation was found between fibroblast and tumour cell radiosensitivity (r=0.57, p=0.03), but a weak inverse association was found between lymphocyte and tumour cell radiosensitivity (r= -0.32, p=0.03). Patients with radiosensitive lymphocytes and tumour cells had higher levels of late complications than those whose cells were radioresistant. CONCLUSION: The work described highlights the importance of cellular radiosensitivity as a parameter determining the clinical response to radiotherapy.