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Biomedical subjects

A O'Neill

Publications and source records attributed to A O'Neill.

At least 19 recordsLinked to original sources
PubMed2004

Hypoxia inhibits human bladder smooth muscle cell proliferation: a potential mechanism of bladder dysfunction.

AIMS: Recent animal studies have suggested that bladder outflow obstruction causes bladder wall hypoxia during both the filling and the voiding phases of the micturition cycle. We have previously demonstrated that mechanical deformation of human detrusor leads to smooth muscle (SM) cell hypertrophy and hyperplasia, which may then contribute to hypoxia in the dysfunctional bladder. We hypothesise that the detrusor's response to a hypoxic environment contributes to bladder dysfunction. The aim of this study was to evaluate the effect of hypoxia on detrusor cell survival and growth. METHODS: Normal human detrusor muscle was obtained at radical cystectomy and primary cultures were established. Cells were then cultured in the presence of 1% oxygen in a hypoxic chamber for different times. Apoptosis was assessed by propidium iodide DNA staining and flow cytometry. Proliferation was assessed by radiolabelled thymidine incorporation. Cell supernatants were retained for growth factor estimation by enzyme linked immuno-sorbent assay (ELISA), and total cell and nuclear extracts were isolated for Western blotting. RESULTS: SM cells responded to the presence of hypoxia through significant upregulation of survival factors hypoxia inducible factor (HIF 1alpha) and vascular endothelial growth factor (VEGF) in a time-dependent manner. Hypoxia did not induce cell death, but significantly reduced the rate of proliferation over time, associated with an increase in the cell cycle inhibitor p27kip1. CONCLUSIONS: In an in vitro human detrusor cell culture model, cells demonstrate a resistance to hypoxia-induced apoptosis but proliferation is inhibited. We suggest that the anti-proliferative effects of hypoxia may limit the ability of detrusor cells to respond to, and compensate for, alterations in their environment contributing to bladder dysfunction.

Apoptosis↗
PubMed2004

Multicenter linkage study of schizophrenia loci on chromosome 22q.

The hypothesis of the existence of one or more schizophrenia susceptibility loci on chromosome 22q is supported by reports of genetic linkage and association, meta-analyses of linkage, and the observation of elevated risk for psychosis in people with velocardiofacial syndrome, caused by 22q11 microdeletions. We tested this hypothesis by evaluating 10 microsatellite markers spanning 22q in a multicenter sample of 779 pedigrees. We also incorporated age at onset and sex into the analysis as covariates. No significant evidence for linkage to schizophrenia or for linkage associated with earlier age at onset, gender, or heterogeneity across sites was observed. We interpret these findings to mean that the population-wide effects of putative 22q schizophrenia susceptibility loci are too weak to detect with linkage analysis even in large samples.

Chromosome Mapping↗
PubMed2004

Gene profiling of in vitro and in vivo models of delayed neutrophil apoptosis: a common pathway?

Mechanisms responsible for the termination of an inflammatory response include the activation of a genetic programme of cellular suicide termed apoptosis, which leads to the elimination of the cellular effectors of acute inflammation, particularly the neutrophil. However, delays in this response result in the persistence of inflammation and the development of inflammatory disorders. Understanding the mechanism that inhibits the process of cell death may be helpful in the treatment of inflammatory disorders. Inflammatory cytokines have been shown to inhibit apoptosis through stabilization of the mitochondria and inhibition of the caspase cascade. To date, how these processes are inhibited remains the central question. We hypothesize that the decision for the delay in neutrophil apoptosis is made through signals delivered on the cell surface, which activate combinations of specific genes that inhibit the cell death pathway. Gene chip microarray experiments were performed in in vivo and in vitro models of delayed neutrophil apoptosis. Analysis has yielded changes in a large number of genes involved in inflammation, metabolism, signalling, mitochondrial function and apoptosis. A number of genes have been identified as suitable targets responsible for the regulation of neutrophil apoptosis and their expression was confirmed by real-time PCR and explored at the level of the protein. Their functional role in the apoptotic response is now being determined. One significant finding is that the gene patterns of delay in vitro and in vivo appear to be different, indicating the possibility for different pathways regulating the delay in neutrophil apoptosis.

Apoptosis↗
PubMed2002

Survival of patients with newly diagnosed glioblastoma multiforme treated with RSR13 and radiotherapy: results of a phase II new approaches to brain tumor therapy CNS consortium safety and efficacy study.

PURPOSE: The objectives of this phase II study were to determine survival, safety, pharmacokinetics (PK), and pharmacodynamics (PD) of 2,4-[[(3,5-dimethylanilino)carbonyl]methyl]phenoxy]-2-methylpropionic acid (RSR13, efaproxiral) 100 mg/kg per day administered with standard cranial radiotherapy (RT) for the treatment of glioblastoma multiforme (GBM). RSR13, a synthetic allosteric modifier of hemoglobin, is a radiation-enhancing agent that noncovalently binds to hemoglobin, reduces oxygen-binding affinity, and increases oxygen unloading to hypoxic tissue. PATIENTS AND METHODS: Fifty patients with newly diagnosed GBM (Karnofsky performance status >or= 60) were enrolled onto this multicenter phase II study. Patients received daily RSR13 100 mg/kg intravenously infused for 30 minutes immediately before cranial RT (60 Gy in 30 fractions). Supplemental oxygen was given during RSR13 infusion and continued until after the RT treatment was completed. RT was given within 30 minutes of the end of RSR13 infusion. PK and PD determinations were performed. RESULTS: The median survival for the RSR13-treated patients was 12.3 months with 1-year and 18-month survival rates of 54% and 24%, respectively. Twenty-four percent of patients had greater than grade 2 toxicity, which was generally transient and self-limited. A significant PD effect on hemoglobin-oxygen binding affinity was demonstrated for most patients. CONCLUSION: RSR13 (100 mg/kg) administered immediately before cranial RT is well tolerated and is pharmacodynamically active. Median survival in excess of 1 year is favorable.

Adult↗
PubMed2002

HPA axis response to a psychological stressor in generalised social phobia.

Social phobia may be associated with a dysfunction of the hypothalamic-pituitary-adrenal (HPA) axis. In this study we determined HPA axis responsivity to a psychological stressor in patients with social phobia and compared them to healthy controls. Fifteen patients with DSM IV social phobia with a mean score of 77.7 on the Liebowitz Social Anxiety Scale and 15 age and sex matched controls underwent the stressor consisting of mental arithmetic and a short term memory test performed in front of an audience. Plasma levels of cortisol and corticotropin were measured at various intervals throughout the test. Although baseline measures of cortisol did not differ between patients (319.8+/-34.6 nmol/l) and controls (279.5+/-42.7 nmol/l)(t=0.7, df=28, P<0.5) nor did baseline corticotropin values (8.6+/-2.1 pg/ml vs 13.7+/-2.0 pg/ml respectively) (t=-1.8, df=28, P<0.08) this stressor resulted in a significantly greater delta max cortisol response (the difference between baseline values and the maximum increase during the stressor) in patients (167.1+/-23.7 nmol/l) than in controls (106.7+/-16 nmol/l) (t=2.1, df=28, P<0.04). There was no significant difference in delta max corticotropin between groups (patients 8.8+/-2.1 pg/ml vs controls 9.1+/-1.9 pg/ml) (t=-0.08, df=28, P<0.9). This preliminary study indicates that patients with social phobia appear to have a hyper-responsive adrenocortical response to psychological stress.

Adrenal Glands↗
PubMed2002

Retroviral transduction of human peripheral blood lymphocytes with Bcl-X(L) promotes in vitro lymphocyte survival in pro-apoptotic conditions.

The prolonged in vivo survival of genetically modified effector cells is crucial to the success of any (gene-modified) adoptive cellular immunotherapy approach. In cancer clinical trials to date, however, the detection of surviving circulating gene-modified T cells has required highly sensitive techniques. In vitro studies of T cell co-stimulation have shown that up-regulation of the anti-apoptosis gene Bcl-X(L) by ligation of CD28 promotes T cell survival, but not proliferation. Here we have investigated the ability to modulate resistance to apoptosis and improve cell survival by transducing human peripheral blood lymphocytes using a retroviral vector that expresses Bcl-X(L). We show that Jurkat cells transduced with Bcl-X(L) retrovirus were partially resistant to Fas (CD95) antibody-induced apoptosis. Subsequent in vitro assays with transduced primary human lymphocytes demonstrates that over-expression of Bcl-X(L) promotes the survival of lymphocytes cultured in the absence of interleukin-2. Activation-induced apoptosis with anti-CD3(epsilon) antibody, OKT3 is also modulated. Furthermore, Bcl-X(L) over-expression in human lymphocytes delays the onset of apoptosis induced by long-term co-culture with tumour cell lines. Despite this improved in vitro survival, in a preliminary experiment to assess safety, no signs of malignancy or autoimmunity were observed in NOD/SCID mice injected with Bcl-X(L) transduced lymphocytes. These results indicate that expression of Bcl-X(L) in lymphocyte therapy either alone or in conjunction with an additional therapeutic gene could enhance persistence of cells in vivo thereby potentially improving the clinical outcome of adoptive cellular therapy.

Animals↗
PubMed2001

Antimicrobial properties and mode of action of the pyrrothine holomycin.

Holomycin, a member of the pyrrothine class of antibiotics, displayed broad-spectrum antibacterial activity, inhibiting a variety of gram-positive and gram-negative bacteria, with the exception of Enterobacter cloacae, Morganella morganii, and Pseudomonas aeruginosa. The antibiotic lacked activity against the eukaryotic microorganisms Saccharomyces cerevisiae and Candida kefyr. Holomycin exhibited a bacteriostatic response against Escherichia coli that was associated with rapid inhibition of RNA synthesis in whole cells. Inhibition of RNA synthesis could have been a secondary consequence of inhibiting tRNA aminoacylation, thereby inducing the stringent response. However, the levels of inhibition of RNA synthesis by holomycin were similar in a stringent and relaxed pair of E. coli strains that were isogenic except for the deletion of the relA gene. This suggests that inhibition of RNA synthesis by holomycin could reflect direct inhibition of DNA-dependent RNA polymerase. Examination of the effects of holomycin on the kinetics of the appearance of beta-galactosidase in induced E. coli cells was also consistent with inhibition of RNA polymerase at the level of RNA chain elongation. However, holomycin only weakly inhibited E. coli RNA polymerase in assays using synthetic poly(dA-dT) and plasmid templates. Furthermore, inhibition of RNA polymerase was observed only at holomycin concentrations in excess of those required to inhibit the growth of E. coli. It is possible that holomycin is a prodrug, requiring conversion in the cell to an active species that inhibits RNA polymerase.

Anti-Bacterial Agents↗
PubMed2000

Identifying breast cancer patients at high risk for bone metastases.

PURPOSE: To identify patient populations at high risk for bone metastases at any time after diagnosis of operable breast cancer, because these patients are potential beneficiaries of treatment with bisphosphonates. PATIENTS AND METHODS: We evaluated data from 6,792 patients who were randomized in International Breast Cancer Study Group clinical trials between 1978 and 1993. Median follow-up was 10. 7 years. A total of 1,275 patients (18.7%) presented with node-negative disease, whereas 3,354 patients (49.4%) had one to three and 2,163 patients (31.9%) had four or more involved axillary lymph nodes. We also assessed the incidence of subsequent bone metastases in the cohort of 1,220 patients who had a first event in local or regional sites or soft tissue alone. Median follow-up for this cohort was 7.7 years from first recurrence. RESULTS: For the entire population with operable disease, the cumulative incidence of bone metastases at any time was 8.2% at 2 years from randomization and 27.3% at 10 years. The highest cumulative incidences of bone metastases at any time were among patients who had four or more involved axillary nodes at the time of diagnosis (14.9% at 2 years and 40.8% at 10 years) and among patients who had as their first event a local or regional recurrence or a recurrence in soft tissue, without any other overt metastases (21.1% at 2 years from first recurrence and 36.7% at 10 years). CONCLUSION: Treatments to prevent bone metastases may have a major impact on the course of breast cancer and may be most efficiently studied in populations with several involved axillary nodes at the time of presentation and in populations with local or regional recurrence or recurrence in soft tissue.

Aged↗
PubMed2000

The relationship between lymphatic vessell invasion, tumor size, and pathologic nodal status: can we predict who can avoid a third field in the absence of axillary dissection?

PURPOSE: Tangential (2-field) radiation therapy to the breast and lower axilla is typically used in our institution for treating patients with early-stage breast cancer who have 0-3 positive axillary nodes, as determined by axillary dissection, whereas a third supraclavicular/axillary field is added for patients with 4 or more positive nodes. However, dissection may result in complications and added expense. We, therefore, assessed whether clinical or pathologic factors of the primary tumor could reliably predict, in the absence of an axillary dissection, which patients with clinically negative axillary nodes have such limited pathologic nodal involvement that they might be effectively treated with only tangential fields. This would eliminate both the complications of axillary dissection and the added complexity and potential morbidity of a supraclavicular/axillary field. METHODS AND MATERIALS: In this study, 722 women with clinical Stage I or II unilateral invasive breast cancer of infiltrating ductal histology, with clinically negative axillary nodes, at least 6 lymph nodes recovered on axillary dissection, and central pathology review were treated with breast-conserving therapy from 1968 to 1987. Pathologic nodal status was assessed in relation to clinical T stage, the presence of lymphatic vessel invasion (LVI), age, histologic grade, and the location of the primary tumor. RESULTS: LVI, T stage, and tumor location were each significantly correlated with nodal status on univariate analysis. Ninety-seven percent of LVI-negative patients had 0-3 positive axillary nodes compared to 87% of LVI-positive patients. There was no association between T stage and extent of axillary involvement within LVI-negative and LVI-positive subgroups. In a logistic regression model, only LVI remained a significant predictor of having 4 or more positive nodes, although tumor size was of borderline significance. The odds ratio for LVI (positive vs. negative) as a predictor of having 4 or more positive nodes was 3.9 (95% CI, 2.0-7.6). CONCLUSION: For patients with clinical T1-2, N0, infiltrating ductal carcinomas, the presence of LVI is predictive of having 4 or more positive axillary nodes. Only 3% of patients with clinical T1-2, N0, LVI-negative breast cancers had 4 or more positive nodes on axillary dissection. Such patients may be reasonable candidates for treatment with tangential radiation fields in the absence of axillary dissection.

Analysis of Variance↗
PubMed2000

Thiol-mediated apoptosis in prostate carcinoma cells.

BACKGROUND: Glutathione (GSH) maintains an optimum cellular redox potential. Chemical depletion, physical efflux from the cell, or intracellular redistribution of this thiol antioxidant is associated with the onset of apoptosis. The aim of this study was to determine the effects of a thiol-depleting agent, diethylmaleate (DEM), on androgen sensitive and insensitive prostate carcinoma cells. METHODS: LNCaP and PC-3 cell lines were induced to undergo apoptosis by DEM and diamide. Apoptosis was quantified by annexin V binding and propidium iodide incorporation using flow cytometry and was confirmed by DNA gel electrophoresis. Intracellular GSH was quantified using a thiol quantitation kit and the generation of reactive oxygen intermediates was measured using dihydrorhodamine 123. Western blot assessed caspase-3, caspase-8, Bcl-2, and Bcl-XL protein expression. Mitochondrial permeability was measured using DiOC6 and stabilized using bongkrekic acid. RESULTS: DEM and diamide induced apoptosis in both androgen sensitive and insensitive cells. Apoptosis was also induced in an LNCaP transfectant cell line overexpressing Bcl-2. Apoptosis was caspase-3 dependent and caspase-8 independent. Bongkrekic acid partially prevented the effects of DEM on mitochondrial permeability but was unable to prevent the induction of apoptosis. Decreased Bcl-2 and Bci-XL protein expression was observed at the time of initial caspase-3 activation. CONCLUSIONS: This study demonstrates that thiol depletion can be used as an effective means of activating caspase-3 in both androgen sensitive and insensitive prostate carcinoma cells. Direct activation of this effector caspase may serve as a useful strategy for inducing apoptosis in prostate carcinoma cells.

Annexin A5↗
PubMed2000

Conventional-dose chemotherapy compared with high-dose chemotherapy plus autologous hematopoietic stem-cell transplantation for metastatic breast cancer. Philadelphia Bone Marrow Transplant Group.

BACKGROUND: We conducted a randomized trial in which we compared high-dose chemotherapy plus hematopoietic stem-cell rescue with a prolonged course of monthly conventional-dose chemotherapy in women with metastatic breast cancer. METHODS: Women 18 to 60 years of age who had metastatic breast cancer received four to six cycles of standard combination chemotherapy. Patients who had a complete or partial response to induction chemotherapy were then randomly assigned to receive either a single course of high doses of carboplatin, thiotepa, and cyclophosphamide plus transplantation of autologous hematopoietic stem cells or up to 24 cycles of cyclophosphamide, methotrexate, and fluorouracil in conventional doses. The primary end point was survival. RESULTS: The median follow-up was 37 months. Of 553 patients who enrolled in the study, 58 had a complete response to induction chemotherapy and 252 had a partial response. Of these, 110 patients were assigned to receive high-dose chemotherapy plus hematopoietic stem cells and 89 were assigned to receive conventional-dose chemotherapy. In an intention-to-treat analysis, we found no significant difference in survival overall at three years between the two treatment groups (32 percent in the transplantation group and 38 percent in the conventional-chemotherapy group). There was no significant difference between the two treatments in the median time to progression of the disease (9.6 months for high-dose chemotherapy plus hematopoietic stem cells and 9.0 months for conventional-dose chemotherapy). CONCLUSIONS: As compared with maintenance chemotherapy in conventional doses, high-dose chemotherapy plus autologous stem-cell transplantation soon after the induction of a complete or partial remission with conventional-dose chemotherapy does not improve survival in women with metastatic breast cancer.

Adolescent↗
PubMed2000

A phase II study of preradiation chemotherapy followed by external beam radiotherapy for the treatment of patients with newly diagnosed glioblastoma multiforme: an Eastern Cooperative Oncology Group study (E2393).

Recent publications support the use of preradiation chemotherapy in the treatment of selected primary brain tumors. In the pediatric population, this treatment strategy often delays radiotherapy and may improve the outcome in patients. This manuscript describes the use of a preradiation chemotherapy approach for adult patients with newly diagnosed glioblastoma multiforme. The main objective of this trial was to determine the feasibility of delivering up to 3 monthly cycles of a 72 h continuous simultaneous intravenous infusion of BCNU (40 mg/m2/day) and cisplatin (40 mg/m2/day). Patients were evaluated for tumor response or progression after each cycle. Following the completion of the chemotherapy treatments or evidence of tumor progression, patients underwent external beam radiotherapy. A dose of 45 Gy was delivered to the pretreatment tumor volume plus surrounding edema and a margin of 3.0 cm. An additional 14.4 Gy was delivered to the preoperative volume plus a 2 cm margin. Fifty patients were enrolled, 47 were eligible and analyzable. Overall, 79% of patients were able to complete at least 2 cycles of treatment, exceeding the predefined measure of feasibility. One patient achieved a complete response, 10 patients a partial response and 18 patients had stable disease at completion of the chemotherapy treatments. Twenty-four patients experienced grade 4 toxicity, mostly hematologic. All patients were able to undergo radiotherapy following chemotherapy. These results indicate that a preradiation strategy is feasible. Although responses to the chemotherapy were seen, a phase III trial is needed to determine whether this approach provides an advantage over standard treatment; such a phase III trial has been undertaken by ECOG.

Adult↗
PubMed2000

Neutrophil apoptosis is delayed in patients with inflammatory bowel disease.

Delayed neutrophil apoptosis is a feature of persistent acute inflammation. Neutrophil-mediated damage has been shown to be associated with the development of inflammatory bowel disease (IBD). Persistence of these cells both at the colonic site and circulation may further contribute to IBD. The aims of this study were to determine whether neutrophils isolated from IBD patients delay apoptosis and to investigate possible mechanisms involved in this delay. We studied 20 patients with IBD, 13 with Crohn's disease, and 7 with ulcerative colitis, all of whom were undergoing intestinal resection for symptomatic disease. Seventeen patients undergoing elective resection of colon cancer acted as operative controls. Systemic, mesenteric arterial, and mesenteric venous blood was harvested. Neutrophils isolated from patients with IBD showed decreased spontaneous apoptosis compared to cancer patients. Mesenteric venous serum of IBD patients contributed to this delay, which contained higher concentrations of interleukin-8 (IL-8). Pro-caspase 3 expression was also reduced in IBD neutrophils, which may contribute to decreased spontaneous and Fas antibody-induced apoptosis. Neutrophil apoptosis may be altered in Crohn's disease and ulcerative colitis through release of anti-apoptotic cytokines and altered caspase expression. The alterations in cell death mechanisms may lead to persistence of the inflammatory response associated with IBD.

Adolescent↗
PubMed2000

RNA polymerase inhibitors with activity against rifampin-resistant mutants of Staphylococcus aureus.

A collection of rifampin-resistant mutants of Staphylococcus aureus with characterized RNA polymerase beta-subunit (rpoB) gene mutations was cross-screened against a number of other RNA polymerase inhibitors to correlate susceptibility with specific rpoB genotypes. The rpoB mutants were cross-resistant to streptolydigin and sorangicin A. In contrast, thiolutin, holomycin, corallopyronin A, and ripostatin A retained activity against the rpoB mutants. The second group of inhibitors may be of interest as drug development candidates.

Anti-Bacterial Agents↗
PubMed2000

Monocarboxylic acid transporters, MCT1 and MCT2, in cortical astrocytes in vitro and in vivo.

We used sequence-specific antibodies to characterize two monocarboxylic acid transporters, MCT1 and MCT2, in astrocytes. Both proteins are expressed in primary cultures of cortical astrocytes, as indicated by immunoblotting and immunofluorescence. Both MCT1 and MCT2 are present in small, punctate structures in the cytoplasm and at the cell membrane. Cells showing very low levels of labeling for glial fibrillary acidic protein (GFAP) also label more dimly for MCT2, but not for MCT1. In vivo, double-label immunofluorescence studies coupled with confocal microscopy indicate that MCT1 and MCT2 are rare in astrocytes in the cortex. However, they are specifically labeled in astrocytes of the glial limiting membrane and in white matter tracts. Both transporters are also present in the microvasculature. Comparison of labeling for MCT1 and MCT2 with markers of the blood-brain barrier shows that the transporters are not always limited to the astrocytic endfeet in vivo. Our results suggest that the level of expression of monocarboxylic acid transporters MCT1 and MCT2 by cortical astrocytes in vivo is significantly lower than in vitro but that astrocytes in some other regions of the brain can express one or both proteins in significant amounts.

Animals↗
PubMed2000

Phase II trial of doxorubicin and docetaxel plus granulocyte colony-stimulating factor in metastatic breast cancer: Eastern Cooperative Oncology Group Study E1196.

PURPOSE: The purpose of this multi-institutional phase II trial was to evaluate the efficacy and toxicity of doxorubicin and docetaxel plus granulocyte colony-stimulating factor (G-CSF) in patients with metastatic breast cancer. The primary objective was to determine whether the combination produced a response rate of at least 50%. PATIENTS AND METHODS: Fifty-four patients with metastatic breast cancer received doxorubicin (60 mg/m(2) by intravenous [IV] injection) followed 1 hour later by docetaxel (60 mg/m(2) by IV infusion over 1 hour) every 3 weeks for up to eight cycles. All patients also received G-CSF. RESULTS: Objective response occurred in 29 (57%) of 51 eligible patients (95% confidence interval [CI], 42% to 70%), including three patients who had a complete response (6%; 95% CI, 1% to 16%). The median response duration was 7 months (95% CI, 6.0 to 15.0 months), median time to treatment failure was 7. 6 months (95% CI, 6.2 to 9.9 months), and the median survival was 27. 5 months (95% CI, 21.5 months to upper limit not reached). The median cumulative doxorubicin dose was 395 mg/m(2) (range, 60 to 480 mg/m(2)). Fifteen patients (28%) were documented to have a decrease in the left ventricular ejection fraction below normal, and three patients (6%; 95% CI, 1% to 15%) developed congestive heart failure. CONCLUSION: Using criteria that we had defined a priori, the doxorubicin-docetaxel regimen as used in this study was sufficiently active and tolerable to justify a phase III comparison with doxorubicin-cyclophosphamide in early-stage breast cancer.

Adult↗
PubMed2000

NCCN Practice Guidelines for Cancer Pain.

The overall approach to pain management encompassed in these guidelines is comprehensive. It is based on objective pain assessments, utilizes both pharmacologic and nonpharmacologic interventions, and requires continual reevaluation of the patient. The NCCN Cancer Pain Practice Guidelines Panel believes that cancer pain can be well controlled in the vast majority of patients if the algorithms presented are systematically applied, carefully monitored, and tailored to the needs of the individual patient.

Acetaminophen↗