ABSTRACT
BACKGROUND: Microscopically positive margins to lymph node metastases (R1LNM) are associated with poorer oncological outcomes in patients with Stage 3 colon cancer. These poorer outcomes were seen despite a greater proportion of these patients receiving adjuvant chemotherapy when compared to those with microscopically negative (R0) margins. We sought to determine if differences in the type or duration of adjuvant chemotherapy could account for the differences in outcomes seen between patients with R0 and R1LNM margins. METHODS: A multicentre retrospective study including patients undergoing surgery for Stage 3 colon cancer between 2016-2019 at specialist centres. Patients were stratified according to margins status (R0 vs R1LNM). Type/duration of chemotherapy and oncological outcomes were compared between groups. RESULTS: 718 patients were included, of whom 100 had R1LNM margins (13.1%). Patients with R1LNM margins had significantly poorer 3-year distant metastases-free (R0 78.2% (95% CI 74.5-81.3) versus R1LNM 58.8% (95% CI 47.2-68.6), p < 0.001) and disease specific survival (R0 88.3% (95% CI 85.2-90.9) versus R1LNM 78.5% (95% CI 68.0-85.8), p < 0.001) when compared to those with R0 margins. No differences were noted in the proportion of patients who completed long-course chemotherapy or were treated with oxaliplatin-based combinations between the R1LNM and R0 groups. Differences in outcomes between R0 and R1LNM groups persisted even when only those patients who completed long-course chemotherapy were compared. DISCUSSION: Differences in adjuvant chemotherapy do not appear to account for the poorer oncological outcomes seen in patients with R1LNM margins after surgery for Stage 3 colon cancer. This suggests that adjuvant chemotherapy may be less effective in this patient group. Further studies to elucidate a potential biological basis for this difference are warranted.
Subject(s)
Colonic Neoplasms , Humans , Retrospective Studies , Colonic Neoplasms/drug therapy , Colonic Neoplasms/surgery , Colonic Neoplasms/pathology , Chemotherapy, Adjuvant , Oxaliplatin/therapeutic useABSTRACT
Mechanisms regulating the transition of mammary epithelial cells (MECs) to mammary stem cells (MaSCs) and to tumor-initiating cells (TICs) have not been entirely elucidated. The p53 family member, p63, is critical for mammary gland development and contains transactivation domain isoforms, which have tumor-suppressive activities, and the ΔN isoforms, which act as oncogenes. In the clinic, p63 is often used as a diagnostic marker, and further analysis of the function of TAp63 in the mammary gland is critical for improved diagnosis and patient care. Loss of TAp63 in mice leads to the formation of aggressive metastatic mammary adenocarcinoma at 9-16 months of age. Here we show that TAp63 is crucial for the transition of mammary cancer cells to TICs. When TAp63 is lost, MECs express embryonic and MaSC signatures and activate the Hippo pathway. These data indicate a crucial role for TAp63 in mammary TICs and provide a mechanism for its role as a tumor- and metastasis-suppressor in breast cancer.
Subject(s)
Breast Neoplasms/pathology , Carcinogenesis , Phosphoproteins/metabolism , Protein Serine-Threonine Kinases/metabolism , Signal Transduction , Trans-Activators/metabolism , AMP-Activated Protein Kinases , Animals , Breast Neoplasms/genetics , Breast Neoplasms/metabolism , Cell Count , Cell Line, Tumor , Cell Polarity , Cell Transformation, Neoplastic , Epithelial-Mesenchymal Transition , Female , Gene Knockdown Techniques , Hippo Signaling Pathway , Humans , Hyperplasia , Mammary Glands, Animal/pathology , Mammary Glands, Animal/physiopathology , Mice , Neoplastic Stem Cells/pathology , Phosphoproteins/deficiency , Phosphoproteins/genetics , Protein Serine-Threonine Kinases/genetics , Regeneration , Trans-Activators/deficiency , Trans-Activators/genetics , Transcription, GeneticABSTRACT
Reactivation of hepatitis B virus (hbv) is a reported complication for patients undergoing chemotherapy, particularly immunochemotherapy with anti-CD20 agents such as rituximab. However, as the use of molecularly targeted agents increases, the risk of viral reactivation is less clearly defined. Here, we present the case of a 62-year-old woman with newly diagnosed EGFR mutation-positive metastatic non-small-cell lung cancer (nsclc). Per interview, our patient had a remote history of hbv infection. She was started on erlotinib and developed profound diarrhea leading to renal failure that required hospital admission and temporary discontinuation of erlotinib. At 8 days after erlotinib cessation, she had a marked spike in her liver function tests, with viral serologies that were consistent with hbv reactivation. Although erlotinib and other tyrosine kinase inhibitors (tkis) are not classically associated with hbv reactivation, hbv reactivation can occur even in the setting of tki withdrawal. Before tki initiation, careful patient screening in those at risk for hbv should be performed to attenuate preventable hepatotoxicity and to differentiate between other causes of hepatotoxicity (for example, drug-induced toxicity).
Subject(s)
Antineoplastic Agents/therapeutic use , Histone Deacetylase Inhibitors/therapeutic use , Hydroxamic Acids/therapeutic use , Indoles/therapeutic use , Ovarian Neoplasms/drug therapy , Sex Cord-Gonadal Stromal Tumors/drug therapy , Adult , Aged , Antineoplastic Agents/pharmacology , Clinical Trials, Phase II as Topic , Female , Histone Deacetylase Inhibitors/pharmacology , Humans , Hydroxamic Acids/pharmacology , Indoles/pharmacology , Middle Aged , Panobinostat , Treatment OutcomeABSTRACT
In Vietnam, serological post H5N1 vaccination surveillance using the HI test is applied to assess the efficiency of the vaccination in addition to virological monitoring. In this paper we report on the evaluations of the performances of the haemagglutination inhibition (HI) test and of a H5-ELISA, using chicken and duck field samples. The evaluations were conducted by comparison with a pseudotyped-based virus neutralization test (H5pp VNT) performed in a reference laboratory and considered as a "gold standard" and also by using methods developed for imperfect reference test. Their global accuracy and best cut-offs were also estimated. Results from the HI test for several haemagglutinin subtypes and from a commercial type A influenza competition ELISA were also compared. The results showed that performance of the HI test was very good in comparison with the H5pp VNT. Data also clearly supported the cut-off of ≥ 4 log(2) used for the HI test for chickens but, a 3 log(2) positivity cut-off would be more appropriate for ducks. When compared with the VNT, the H5-ELISA showed poor specificity when using the positivity cut-off specified by the manufacturer but could be used as a screening test if confirmed by the HI test or the H5ppVNT which presents some interests for large scale testing (no need for biosafety level 3 conditions and high performance). A general and highly sensitive pre-screening can also be achieved using the detection of NP-specific antibodies with a competition ELISA. This appears of little interest in a context of high subtypes diversity where only a subtype is targeted for surveillance and control.
Subject(s)
Chickens/virology , Ducks/virology , Enzyme-Linked Immunosorbent Assay/veterinary , Hemagglutination Inhibition Tests/veterinary , Influenza A Virus, H5N1 Subtype/isolation & purification , Influenza in Birds/diagnosis , Animals , Antibodies, Viral/blood , Bayes Theorem , Influenza A Virus, H5N1 Subtype/immunology , Influenza in Birds/epidemiology , Influenza in Birds/virology , Neutralization Tests/veterinary , Poultry/virology , Prevalence , ROC Curve , Sensitivity and Specificity , Vietnam/epidemiologyABSTRACT
Bacterial cell morphogenesis requires coordination among multiple cellular systems, including the bacterial cytoskeleton and the cell wall. In the vibrioid bacterium Caulobacter crescentus, the intermediate filament-like protein crescentin forms a cell envelope-associated cytoskeletal structure that controls cell wall growth to generate cell curvature. We undertook a genetic screen to find other cellular components important for cell curvature. Here we report that deletion of a gene (wbqL) involved in the lipopolysaccharide (LPS) biosynthesis pathway abolishes cell curvature. Loss of WbqL function leads to the accumulation of an aberrant O-polysaccharide species and to the release of the S layer in the culture medium. Epistasis and microscopy experiments show that neither S-layer nor O-polysaccharide production is required for curved cell morphology per se but that production of the altered O-polysaccharide species abolishes cell curvature by apparently interfering with the ability of the crescentin structure to associate with the cell envelope. Our data suggest that perturbations in a cellular pathway that is itself fully dispensable for cell curvature can cause a disruption of cell morphogenesis, highlighting the delicate harmony among unrelated cellular systems. Using the wbqL mutant, we also show that the normal assembly and growth properties of the crescentin structure are independent of its association with the cell envelope. However, this envelope association is important for facilitating the local disruption of the stable crescentin structure at the division site during cytokinesis.
Subject(s)
Bacterial Proteins/metabolism , Caulobacter crescentus/cytology , Caulobacter crescentus/metabolism , Lipopolysaccharides/biosynthesis , Bacterial Proteins/genetics , Blotting, Western , Caulobacter crescentus/genetics , Lipopolysaccharides/genetics , Microscopy , Signal Transduction/genetics , Signal Transduction/physiologyABSTRACT
The detection of an antibody against nucleoprotein (NP) of the avian influenza virus (AIV) was attempted by an electrochemical immunoassay by combining a secondary antibody-alkaline phosphatase conjugate and 4-aminophenylphosphate. Released 4-aminophenol was quantitated electrochemically, and the current derived from oxidation of the hydrolysis product increased linearly over a wide primary antibody concentration range (10 - 1000 ng/ml). The detection limit of this electrochemical immunoassay for the antibody against the NP of AIV was found to be 10 ng/ml.
Subject(s)
Antibodies, Viral/analysis , Antibodies, Viral/immunology , Enzyme-Linked Immunosorbent Assay/methods , Influenza A Virus, H5N1 Subtype/immunology , Alkaline Phosphatase/metabolism , Aniline Compounds/metabolism , Animals , Antibodies, Viral/metabolism , Disposable Equipment , Electrochemistry , Electrodes , Feasibility Studies , Influenza A Virus, H5N1 Subtype/isolation & purification , Organophosphorus Compounds/metabolismABSTRACT
Using a multi-tiered, case-control association design, scanning 25 215 gene-centric SNPs, we previously identified two psoriasis susceptibility genes: IL12B and IL23R. These results have recently been confirmed. To better characterize the IL23R psoriasis-association, we used a fine mapping strategy to identify 59 additional IL23R-linked SNPs, which were genotyped in our three independent, white North American sample sets (>2800 individuals in toto). A sliding window of haplotype association demonstrates colocalization of psoriasis susceptibility effects within the boundaries of IL23R across all sample sets, thereby decreasing the likelihood that neighboring genes, particularly IL12RB2, are driving the association at this region. Additional haplotype work identified two 5-SNP haplotypes with strong protective effects, consistent across our three sample sets (OR(common)=0.67; P(comb)=4.32E-07). Importantly, heterogeneity of effect was extremely low between sample sets for these haplotypes (P(Het)=0.961). Together, these protective haplotypes attain a frequency of 16% in controls, declining to 11% in cases. The characterization of association patterns within IL23R to specific predisposing/protective variants will play an important role in the elucidation of psoriasis etiology and other related phenotypes. Further, this work is essential to lay the foundation for the role of IL23R genetics in response to pharmaceutical therapy and dosage.
Subject(s)
Genetic Predisposition to Disease , Psoriasis/genetics , Receptors, Interleukin/genetics , Case-Control Studies , Haplotypes , Humans , Idaho , Polymorphism, Single Nucleotide , UtahABSTRACT
A multitiered genetic association study of 25 215 single-nucleotide polymorphisms (SNPs) in three case-control sample sets (1446 patients and 1432 controls) identified three IL13-linked SNPs (rs1800925, rs20541 and rs848) associated with psoriasis. Although the susceptibility effects at these SNPs were modest (joint allelic odds ratios (ORs): 0.76 to 0.78; P(comb): 1.3E-03 to 2.50E-04), the association patterns were consistent across the sample sets, with the minor alleles being protective. Haplotype analyses identified one common, susceptible haplotype CCG (joint allelic OR=1.27; P(comb)=1.88E-04) and a less common, protective haplotype TTT (joint allelic OR=0.74; P(comb)=7.05E-04). In combination with the other known genetic risk factors, HLA-C, IL12B and IL23R, the variants reported here generate an 11-fold psoriasis-risk differential. Residing in the 5q31 cytokine gene cluster, IL13 encodes an important T-cell-derived cytokine that regulates cell-mediated immunity. These results provide the foundation for additional studies required to fully dissect the associations within this cytokine-rich genomic region, as polymorphisms in closely linked candidate genes, such as IRF1, IL5 or IL4, may be driving these results through linkage disequilibrium.
Subject(s)
Chromosomes, Human, Pair 5/immunology , Cytokines/genetics , Genetic Variation/immunology , Multigene Family/genetics , Psoriasis/genetics , Case-Control Studies , Haplotypes/immunology , Humans , Psoriasis/epidemiology , Psoriasis/immunologyABSTRACT
BACKGROUND: High cure rates are expected in good-risk metastatic nonseminomatous germ-cell tumor (NSGCT) patients with bleomycin, etoposide and cisplatin. PATIENTS AND METHODS: Patients received either three cycles of BE500P or four cycles of E500P every 3 weeks. Disease was defined according to the Institut Gustave Roussy prognostic model. Patients were retrospectively assigned into the International Germ Cell Cancer Collaborative Group (IGCCCG) classification. A sample size of 250 patients was necessary for an expected favorable response rate (primary end point) of 90% and not more than a 10% difference between the two arms. RESULTS: Among 257 assessable patients, 124 and 122 patients achieved a favorable response in the 3BE500P and 4E500P arms, respectively (P = 0.34). Median follow-up was 53 months. The 4-year event-free survival rates were 91% and 86%, respectively (P = 0.135). The 4-year overall survival rates were not significantly different [five deaths versus 12 deaths, respectively (P = 0.096)]. Similar nonsignificant trends were observed in good IGCCCG prognosis patients. CONCLUSIONS: Both regimens produced similar results in terms of favorable response rates. As the trial was underpowered for survival analyses, conclusive data would require a larger randomized trial. Unless such a study is done, 3BE500P is the treatment of choice for metastatic NSGCT patients.
Subject(s)
Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Bleomycin/therapeutic use , Cisplatin/therapeutic use , Etoposide/therapeutic use , Neoplasms, Germ Cell and Embryonal/drug therapy , Testicular Neoplasms/drug therapy , Adolescent , Adult , Antineoplastic Combined Chemotherapy Protocols/adverse effects , Bleomycin/adverse effects , Cisplatin/adverse effects , Etoposide/adverse effects , Follow-Up Studies , Humans , Male , Middle Aged , Neoplasm Metastasis/drug therapy , Neoplasm Metastasis/pathology , Neoplasms, Germ Cell and Embryonal/pathology , Risk Factors , Survival Analysis , Testicular Neoplasms/pathology , Time Factors , Treatment OutcomeABSTRACT
Highly pathogenic avian influenza virus H5N1 is endemic in poultry in East and Southeast Asia with disease outbreaks recently spreading to parts of central Asia, Europe and Africa. Continued interspecies transmission to humans has been reported in Vietnam, Thailand, Cambodia, Indonesia and China, causing pandemic concern. Here, we genetically characterize 82 H5N1 viruses isolated from poultry throughout Indonesia and Vietnam and 11 human isolates from southern Vietnam together with sequence data available in public databases to address questions relevant to virus introduction, endemicity and evolution. Phylogenetic analysis shows that all viruses from Indonesia form a distinct sublineage of H5N1 genotype Z viruses suggesting this outbreak likely originated from a single introduction that spread throughout the country during the past two years. Continued virus activities in Indonesia were attributed to transmission via poultry movement within the country rather than through repeated introductions by bird migration. Within Indonesia and Vietnam, H5N1 viruses have evolved over time into geographically distinct groups within each country. Molecular analysis of the H5N1 genotype Z genome shows that only the M2 and PB1-F2 genes were under positive selection, suggesting that these genes might be involved in adaptation of this virus to new hosts following interspecies transmission. At the amino acid level 12 residues were under positive selection in those genotype Z viruses, in the HA and PB1-F2 proteins. Some of these residues were more frequently observed in human isolates than in avian isolates and are related to viral antigenicity and receptor binding. Our study provides insight into the ongoing evolution of H5N1 influenza viruses that are transmitting in diverse avian species and at the interface between avian and human hosts.
Subject(s)
Influenza A Virus, H5N1 Subtype/physiology , Influenza A Virus, H5N1 Subtype/pathogenicity , Influenza in Birds/epidemiology , Influenza, Human/epidemiology , Animals , Asia, Southeastern , Birds , Disease Outbreaks , Humans , Indonesia , Influenza A Virus, H5N1 Subtype/classification , Influenza A Virus, H5N1 Subtype/genetics , Molecular Sequence Data , Phylogeny , Vietnam/epidemiology , ZoonosesABSTRACT
Increased serum levels of S100B are positively correlated with multiple forms of CNS damage, such as stroke, CNS trauma and neurodegenerative diseases, but also in psychiatric disorders. However, it is currently not known whether increased serum levels of S100B reflect a neuroregenerative or neurodegenerative response. Since glutamate receptor overactivation (excitotoxicity) may contribute to neuronal pathology in psychiatric disorders, we investigated the effect of S100B on N-methyl-d-aspartate (NMDA)-induced neuronal cell death. Here we demonstrate that very low concentrations of S100B significantly protect primary rat hippocampal neurons against NMDA toxicity by activation of transcription factors of the Rel/nuclear factor kappaB (NF-kappaB) family. Further experiments suggest that i) S100B activated expression of the receptor of advanced glycation products (RAGE) gene in neurons and ii) S100B induced a unique composition of the active NF-kappaB complex consisting of the p65 and c-Rel subunits suggesting a novel mechanism for NF-kappaB activation involved in S100B-mediated neuroprotection. Our data suggest that S100B secreted during the glial response to brain injury potently activates p65/c-Rel in a RAGE-dependent manner and may exert neuroprotective and neuroregenerative effects in psychiatric disorders.
Subject(s)
Carrier Proteins/biosynthesis , Excitatory Amino Acid Agonists/toxicity , Hippocampus/drug effects , Neoplasm Proteins/biosynthesis , Nucleocytoplasmic Transport Proteins , Proto-Oncogene Proteins c-rel/biosynthesis , S100 Proteins/pharmacology , Animals , Animals, Newborn , Brain Injuries/genetics , Brain Injuries/metabolism , Carrier Proteins/genetics , Cell Death/drug effects , Cell Death/physiology , Cells, Cultured , Hippocampus/metabolism , Neoplasm Proteins/genetics , Nerve Growth Factors , Neurons/drug effects , Neurons/metabolism , Proto-Oncogene Proteins c-rel/genetics , Rats , Rats, Wistar , S100 Calcium Binding Protein beta Subunit , Transcription, Genetic/physiologyABSTRACT
NGF has been shown to support neuron survival by activating the transcription factor nuclear factor-kappaB (NFkappaB). We investigated the effect of NGF on the expression of Bcl-xL, an anti-apoptotic Bcl-2 family protein. Treatment of rat pheochromocytoma PC12 cells, human neuroblastoma SH-SY5Y cells, or primary rat hippocampal neurons with NGF (0.1-10 ng/ml) increased the expression of bcl-xL mRNA and protein. Reporter gene analysis revealed a significant increase in NFkappaB activity after treatment with NGF that was associated with increased nuclear translocation of the active NFkappaB p65 subunit. NGF-induced NFkappaB activity and Bcl-xL expression were inhibited in cells overexpressing the NFkappaB inhibitor, IkappaBalpha. Unlike tumor necrosis factor-alpha (TNF-alpha), however, NGF-induced NFkappaB activation occurred without significant degradation of IkappaBs determined by Western blot analysis and time-lapse imaging of neurons expressing green fluorescent protein-tagged IkappaBalpha. Moreover, in contrast to TNF-alpha, NGF failed to phosphorylate IkappaBalpha at serine residue 32, but instead caused significant tyrosine phosphorylation. Overexpression of a Y42F mutant of IkappaBalpha potently suppressed NFG-, but not TNF-alpha-induced NFkappaB activation. Conversely, overexpression of a dominant negative mutant of TNF receptor-associated factor-6 blocked TNF-alpha-, but not NGF-induced NFkappaB activation. We conclude that NGF and TNF-alpha induce different signaling pathways in neurons to activate NFkappaB and bcl-x gene expression.
Subject(s)
DNA-Binding Proteins/metabolism , I-kappa B Proteins , NF-kappa B/metabolism , Nerve Growth Factor/pharmacology , Proto-Oncogene Proteins c-bcl-2/biosynthesis , Animals , Animals, Newborn , Cell Survival , Cysteine Endopeptidases , Gene Expression Regulation , Hippocampus/cytology , Multienzyme Complexes/antagonists & inhibitors , NF-KappaB Inhibitor alpha , Neurons/drug effects , PC12 Cells , Phosphorylation , Proteasome Endopeptidase Complex , RNA, Messenger , Rats , Rats, Inbred F344 , Serine , Tumor Necrosis Factor-alpha/pharmacology , Tyrosine , bcl-X ProteinABSTRACT
PURPOSE: To identify most significant and therapeutically relevant prognostic factors in adults with localized primary synovial sarcomas (SS) and to confirm the usefulness of the French Federation of Cancer Centers (FNCLCC) grading system, the prognostic impact of which has been already proven in soft tissue sarcomas. PATIENTS AND METHODS: Data on 128 patients with nonmetastatic SS collected from a cooperative database by the FNCLCC Sarcoma Group between 1980 and 1994 were studied retrospectively. Immunohistochemistry was performed at diagnosis in 77 cases (61%). The tumors were classified as biphasic (n = 45), monophasic fibrous (n = 72), and poorly differentiated (n = 10) subtypes. Histologic grade was determined according to the FNCLCC method, and vascular invasion was assessed in every case. RESULTS: The 5-year disease-specific survival (DSS) rate for this series of patients with localized SS was 62.9% (+/- 9.6% [SD]) with a median follow-up time of 37 months (range, 8 to 141 months). In multivariate analysis, the adverse risk factors associated with decreased DSS were International Union Against Cancer/American Joint Committee on Cancer stage III/IVA disease, male sex, and truncal tumor locations. For metastasis-free survival (MFS), disease stage III/IVA, tumor necrosis, and monophasic subtypes were the major factors associated with a less favorable prognosis. Separately, when not using disease stage, tumor necrosis, and mitotic activity, histologic grade became the most significant prognostic factor for both DSS and MFS. In addition, larger tumors and older patients become associated with a significantly worse prognosis. Independent adverse risk factors for local recurrence-free survival included histologic grade 3 and truncal tumor location. CONCLUSION: These data confirm that not all SS present the same severe outcome. High-risk patients identified on the basis of these parameters may qualify for an aggressive treatment approach.
Subject(s)
Sarcoma, Synovial , Adult , Female , Humans , Immunohistochemistry , Male , Multivariate Analysis , Neoplasm Staging , Prognosis , Proportional Hazards Models , Retrospective Studies , Sarcoma, Synovial/mortality , Sarcoma, Synovial/pathology , Sarcoma, Synovial/therapy , Survival AnalysisABSTRACT
Neuron death in Alzheimer's disease is believed to be triggered by an increased production of amyloidogenic beta-amyloid peptides, involving both increased oxidative stress and activation of a conserved death program. Bcl-xL, an anti-apoptotic protein of the Bcl-2 family, is expressed at high levels in the adult nervous system. Exposure of neuronal cultures to subtoxic concentrations of beta-amyloid peptide 1-40 (1-10microM) or the fragment 25-35 (1-10microM) up-regulated both bcl-xL mRNA and Bcl-xL protein levels, determined by reverse transcriptase-polymerase chain reaction and western blot analysis. Bcl-xL protein was also up-regulated during oxidative stress induced by exposure to hydrogen peroxide (3-100microM) or ferric ions (1-10microM). In contrast, apoptotic stimuli (exposure to staurosporine or serum withdrawal) actually decreased neuronal Bcl-xL expression. To investigate the role of Bcl-xL in cell death relevant to Alzheimer's disease, we stably overexpressed Bcl-xL in human SH-SY5Y neuroblastoma cells. Cells overexpressing Bcl-xL were significantly protected from beta-amyloid neurotoxicity and staurosporine-induced apoptosis compared to vector-transfected controls. In contrast, Bcl-xL overexpression only conferred a mild protection against oxidative injury induced by hydrogen peroxide. We conclude that up-regulation of Bcl-xL expression in response to subtoxic concentrations of beta-amyloid is a stress response that increases the resistance of neurons to beta-amyloid neurotoxicity primarily by inhibiting apoptotic processes.
Subject(s)
Amyloid beta-Peptides/pharmacology , Apoptosis/physiology , Cell Survival/physiology , Neurons/metabolism , Oxidative Stress/physiology , Proto-Oncogene Proteins c-bcl-2/metabolism , Up-Regulation/physiology , Alzheimer Disease/metabolism , Alzheimer Disease/physiopathology , Amyloid beta-Peptides/metabolism , Animals , Apoptosis/drug effects , Brain/drug effects , Brain/metabolism , Brain/physiopathology , Caspases/drug effects , Caspases/metabolism , Cell Survival/drug effects , Humans , Hydrogen Peroxide/pharmacology , Nerve Degeneration/chemically induced , Nerve Degeneration/metabolism , Nerve Degeneration/prevention & control , Neurons/drug effects , Neurotoxins/pharmacology , Oxidants/pharmacology , Oxidative Stress/drug effects , Proto-Oncogene Proteins c-bcl-2/genetics , RNA, Messenger/metabolism , Rats , Tumor Cells, Cultured , Up-Regulation/drug effects , bcl-X ProteinABSTRACT
An increased production of superoxide has been shown to mediate glutamate-induced neuron death. We monitored intracellular superoxide production of hippocampal neurons during and after exposure to the glutamate receptor agonist NMDA (300 microm). During a 30 min NMDA exposure, intracellular superoxide production increased significantly and remained elevated for several hours after wash-out of NMDA. After a 5 min exposure, superoxide production remained elevated for 10 min, but then rapidly returned to baseline. Mitochondrial membrane potential also recovered after wash-out of NMDA. However, recovery of mitochondria was transient and followed by delayed mitochondrial depolarization, loss of cytochrome c, and a secondary rise in superoxide production 4-8 hr after NMDA exposure. Treatment with a superoxide dismutase mimetic before the secondary rise conferred the same protection against cell death as a treatment before the first. The secondary rise could be inhibited by the complex I inhibitor rotenone (in combination with oligomycin) and mimicked by the complex III inhibitor antimycin A. To investigate the relationship between cytochrome c release and superoxide production, human D283 medulloblastoma cells deficient in mitochondrial respiration (rho(-) cells) were exposed to the apoptosis-inducing agent staurosporine. Treatment with staurosporine induced mitochondrial release of cytochrome c, caspase activation, and cell death in control and rho(-) cells. However, a delayed increase in superoxide production was only observed in control cells. Our data suggest that the delayed superoxide production in excitotoxicity and apoptosis occurs secondary to a defect in mitochondrial electron transport and that mitochondrial cytochrome c release occurs upstream of this defect.
Subject(s)
Cytochrome c Group/metabolism , Mitochondria/enzymology , Neurons/cytology , Neurotoxins/metabolism , Superoxides/metabolism , Animals , Apoptosis/drug effects , Apoptosis/physiology , Electron Transport/physiology , Electron Transport Complex III/metabolism , Electrons , Excitatory Amino Acid Agonists/pharmacology , Free Radical Scavengers/pharmacology , Glutamic Acid/metabolism , Hippocampus/cytology , Humans , Medulloblastoma , Membrane Potentials/drug effects , Membrane Potentials/physiology , Metalloporphyrins/pharmacology , Mitochondria/drug effects , N-Methylaspartate/pharmacology , Neurons/enzymology , Rats , Rats, Inbred F344 , Reactive Oxygen Species/metabolism , Superoxide Dismutase/metabolism , Tumor Cells, CulturedABSTRACT
Xanthene dyes, i.e., phloxine B and uranine or phloxine B alone, are phototoxic to tephritid fruit flies infesting guava fruits. An analytical method was developed for determination of residues of these dyes used in bait solutions for suppression of the tephritid fruit fly population in guava fruits. The procedure involved solvent extraction, anion-exchange cleanup, and determination by liquid chromatography or capillary zone electrophoresis. The dyes were extracted from 50 g guava fruit at 45 degrees degrees with 400 mL methanol-acetonitrile (1 + 1) and 5 g magnesium oxide added as an alkaline and clarifying agent. The guava extract was adjusted to pH 8.5 and subjected to an amino column cleanup. Average recoveries of xanthene dyes added to guava purees ranged from 77 to 99% for phloxine B and from 79 to 102% for uranine at spiking levels of 0.05-1.00 microg/g. The method was applied to the determination of phloxine B residues in guava fruits collected from a dye-sprayed orchard. After phloxine B was applied at a rate of 62.5 g/ha for 14 weekly sprayings, it was found on guava fruits at an average concentration of 111 +/- 18 ng/g 4 h after the llth spraying. The concentration of phloxine B was 426 +/- 94 ng/g in selected fruits with high deposits of the dye 4 h after spraying. Average concentrations of phloxine B 5 days after the 7th and 14th sprayings were 29 +/- 7 and 19 +/- 8 ng/g, respectively.
Subject(s)
Coloring Agents/analysis , Fruit/chemistry , Xanthenes/analysis , Electrophoresis, Capillary/methods , Eosine I Bluish/analysis , SolventsABSTRACT
Glutamate receptor overactivation contributes to neuron death after stroke, trauma, and epileptic seizures. Exposure of cultured rat hippocampal neurons to the selective glutamate receptor agonist N-methyl-d-aspartate (300 microm, 5 min) or to the apoptosis-inducing protein kinase inhibitor staurosporine (300 nm) induced a delayed neuron death. In both cases, neuron death was preceded by the mitochondrial release of the pro-apoptotic factor cytochrome c. Unlike staurosporine, the N-methyl-d-aspartate-induced release of cytochrome c did not lead to significant activation of caspase-3, the main caspase involved in the execution of neuronal apoptosis. In contrast, activation of the Ca(2+)-activated neutral protease calpain I was readily detectable after the exposure to N-methyl-d-aspartate. In a neuronal cell-free apoptosis system, calpain I prevented the ability of cytochrome c to activate the caspase cascade by inhibiting the processing of procaspase-3 and -9 into their active subunits. In the hippocampal neuron cultures, the inhibition of calpain activity restored caspase-3-like protease activity after an exposure to N-methyl-d-aspartate. Our data demonstrate the existence of signal transduction pathways that prevent the entry of cells into a caspase-dependent cell death program after the mitochondrial release of cytochrome c.
Subject(s)
Apoptosis/drug effects , Calpain/metabolism , N-Methylaspartate/pharmacology , Neurons/drug effects , Animals , Caspases/metabolism , Cells, Cultured , Cytochrome c Group/metabolism , Enzyme Activation , Hippocampus/drug effects , Hippocampus/enzymology , Microscopy, Fluorescence , Mitochondria/drug effects , Mitochondria/enzymology , Neurons/cytology , Neurons/enzymology , RatsABSTRACT
INTRODUCTION: The Schnitzler's syndrome first described in 1972, associates urticaria, bone pain, and monoclonal IgM gammapathy. EXEGESIS: A 50-year-old man presented symptoms of urticaria restricted to the trunk and lower members, with episodes of fever accompanied by inflammatory pain in the knees and legs. Slight deterioration of his general condition was also observed. Biological findings showed the existence of an inflammatory syndrome. Electrophoresis and immunoelectrophoresis provided evidence for the existence of underlying IgM gammapathy. Bone X-ray demonstrated the presence of tibial and peroneal metaphysis thickening, with hyperfixation on bone scintigraphy. The patient's condition improved after cortisone and colchicine treatment, allowing decrease in coricosteroid doses. Two years later, except for urticaria, clinical features have disappeared and no hematological disorder has been observed.