CD20-negative relapse after (131)I-anti-CD20 therapy.
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Aged↗
Biomedical subjects
T O'Brien
Publications and source records attributed to T O'Brien.
The Internet and an orthopaedic discussion group.
Since its inception, the Internet has created many new opportunities for the dissemination of knowledge. We have developed an Internet-based orthopaedic discussion group. There are 93 members from Ireland and elsewhere in the world. Precautions are taken to ensure the confidentiality of all cases submitted to the group. All patient identifiers are removed from images, radiographs and reports before submission. In the first 18 months more than 100 cases were discussed by the group. The use of an Internet-based discussion group in orthopaedics has expanded the educational and communication opportunities for the Irish orthopaedic profession both nationally and internationally.
Education, Medical, Continuing↗
Clomiphene-induced severe hypertriglyceridemia and pancreatitis.
Clomiphene has been available for clinical use since 1960 and has been successfully used to aid fertility in women with certain anovulatory disorders. It is a synthetic estrogen analog, of the triphenylethylene derivative group, and its biochemical structure is similar to that of tamoxifen. Estrogen and tamoxifen lower total and low-density lipoprotein cholesterol and increase triglyceride and high-density lipoprotein cholesterol levels. In patients with baseline hypertriglyceridemia, these agents can induce severe hypertriglyceridemia and pancreatitis. The actions of clomiphene on lipid metabolism have not been studied, and to our knowledge, no cases of severe hypertriglyceridemia related to the use of clomiphene have been described. We report the case of a woman who developed 2 episodes of clomiphene-induced hypertriglyceridemia and pancreatitis while receiving this drug for treatment of infertility. Given the striking structural similarity between clomiphene and tamoxifen, it is likely that clomiphene is capable of inducing severe hypertriglyceridemia in patients with certain underlying lipid disorders by a mechanism similar to that of tamoxifen.
Adult↗
Urinary vascular endothelial growth factor and its correlation with bladder cancer recurrence rates.
PURPOSE: Vascular endothelial growth factor (VEGF) is a principal growth factor mediating tumor angiogenesis. The high expression of VEGF within bladder tumors is associated with a poor prognosis. We quantified urinary VEGF and determined its potential as a prognostic marker in bladder cancer. MATERIALS AND METHODS: VEGF was measured by enzyme-linked immunosorbent assay in the urine of 261 patients, including 153 undergoing cystoscopic surveillance for bladder cancer and 108 with another advanced malignancy or a benign urological condition. The source of urinary VEGF was studied through its quantification in bladder tumors and normal bladders. RESULTS: Urinary VEGF was higher in patients undergoing cystoscopic surveillance for bladder cancer than in those with an advanced nonbladder malignancy (p <0.0001) or a benign urological condition (p = 0.004). The highest levels were noted in patients with bladder cancer compared to those with clear cystoscopy (p <0.0001). In 26 cases the correlation between VEGF protein levels in bladder cancer and urine (r = 0.67, p = 0.003) suggested that the tumor is a source of urinary VEGF. Increased VEGF protein in normal urothelium in 22 patients with bladder cancer compared to that in 7 cadaveric organ donors (p = 0.002) indicates that urinary VEGF may also be derived from nonmalignant urothelium. In 61 cases we established a correlation between urinary VEGF and stage T1 or less superficial bladder tumor recurrence rates (r = 0.45, p <0.0001). CONCLUSIONS: Our study demonstrates that VEGF is high in the urine of patients with bladder cancer and it correlates with tumor recurrence rates. VEGF is implicated in the pathogenesis of bladder cancer recurrence. Its quantification may provide a valuable noninvasive marker for the early detection of bladder tumor recurrence as well as a therapy target.
Adult↗
An orthopaedic discussion group, linking and teaching the orthopaedic community.
Since its inception, the Internet has created many new opportunities for the dissemination of knowledge between individuals. One of the areas most affected by these changes has been healthcare, both in terms of service provision and in the arena of medical education. Other healthcare professionals have described the educational resources available on the Net but few have illustrated the advantages of educational and conversant interaction between members of a surgical speciality or the maturing process that takes place within that group. We describe how the initiation and continued development of an Internet-based discussion group has benefited the orthopaedic profession in Ireland. We identify problems detected to date and possible difficulties in the future of the discussion group.
Education, Medical, Graduate↗
New approaches to prevention and treatment of radial artery graft vasospasm.
BACKGROUND: There has been renewed interest in radial artery (RA) conduits for coronary artery bypass because of the relative resistance of arterial grafts to atherosclerosis compared with autogenous vein grafts. Although improved drug therapy for arterial spasm is now available, vasospasm still occurs in at least 5% to 10% of RA grafts. We systematically evaluated the effectiveness of calcium channel blockers and organic nitrates for inhibition or reversal of RA contraction in vitro. Additionally, we investigated the efficacy of novel gene therapy with endothelial nitric oxide synthase (eNOS) to inhibit RA contractions. METHODS AND RESULTS: Segments of RA from 28 patients undergoing coronary artery bypass grafting were mounted in organ chambers. In control experiments, KCl (5 to 50 mmol/L) produced dose-dependent increases in tension (maximum tension, 14.3 +/- 3.0 g, n = 7). Addition of diltiazem or verapamil had no significant effect on KCl contraction (128 +/- 36% and 88 +/- 24% control, respectively); however, nifedipine markedly inhibited KCl contraction (27 +/- 4% control, P = 0.005). Norepinephrine (NE, 10(-9) to 10(-4) M) produced dose-dependent increases in tension (maximum tension, 15.7 +/- 2.7 g in control rings, n = 8). Diltiazem and verapamil pretreatment had no significant effect on NE contraction (103 +/- 14% and 90 +/- 14% control, respectively); nifedipine significantly inhibited NE contraction (70 +/- 11% control, P = 0.02). Isosorbide dinitrate and nitroglycerin markedly inhibited KCl contractions (47 +/- 9% and 30 +/- 8% of controls, n = 6) and NE contractions (42 +/- 10% and 31 +/- 9% of controls, n = 6). Nifedipine, isosorbide, and nitroglycerin were further evaluated for the ability to reverse an established contraction (KCl 40 mmol/L); nitroglycerin was most effective in reversing RA contraction. In separate experiments, RA underwent adenoviral-mediated gene transfer with vehicle, Escherichia coli beta-galactosidase, or eNOS (eNOS, 10(10) PFU/mL x 1 hour). Transgene expression was confirmed by beta-galactosidase activity and eNOS immunohistochemistry after 40 hours of ex vivo incubation. Immunohistochemistry demonstrated recombinant NOS in adenovirus encoding bovine eNOS (Ad.CMVeNOS) RA only. Ad.CMVeNOS arteries contracted only 46.6 +/- 13.7% of controls to KCl (n = 5) and 48.2 +/- 11.4% of controls to prostaglandin F2 alpha a (10(-9) to 10(-6) M, n = 5). CONCLUSIONS: Diltiazem, which is used empirically to prevent RA vasospasm, had little effect on human RA contractions (receptor-independent and receptor-dependent). Organic nitrates inhibited and reversed RA contractions. Adenoviral transfer of NOS suggests that future clinical application of gene therapy may play an important role in prevention of RA vasospasm.
Adenoviridae↗
Comparison of three methods for the isolation of mycobacteria from bovine tissue lesions.
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Animals↗
Direct and indirect estimates of HIV-1 incidence in a high-prevalence population.
While the worldwide AIDS epidemic continues to expand, directly measured incidence data are difficult to obtain. Methods to reliably estimate human immunodeficiency virus type 1 (HIV-1) incidence from more easily available data are particularly relevant in those parts of the world where prevalence is rising in heterosexually exposed populations. The authors set out to estimate HIV-1 incidence in a population of heterosexual sexually transmitted disease clinic attendees in Trinidad who had a known high prevalence of HIV-1 subtype B. Over the period 1987-1995, HIV-1 incidence estimates from serial cross-sectional studies of HIV-1 prevalence, passive follow-up of clinic recidivists, modeling of early markers of HIV-1 infection (p24 antigen screening), and a cohort study of seronegative genital ulcer disease cases were compared. Measuring incidence density in the genital ulcer disease cases directly gave the highest estimate, 6.9% per annum. Screening for the detection of early HIV-1 markers yielded an incidence of 5.0% per annum, while estimating incidence from serial cross-sectional prevalence data and clinic recidivists gave estimates of 3.5% and 4.5% per annum, respectively. These results were found to be internally consistent. Indirect estimates of incidence based on prevalence data can give accurate surrogates of true incidence. Within limitations, even crude measures of incidence are robust enough for health planning and evaluation purposes. For planning vaccine efficacy trials, consistent conservative estimates may be used to evaluate populations before targeting them for cohort studies.
Blotting, Western↗
Adipocyte macrophage colony-stimulating factor is a mediator of adipose tissue growth.
Adipose tissue growth results from de novo adipocyte recruitment (hyperplasia) and increased size of preexisting adipocytes. Adipocyte hyperplasia accounts for the severalfold increase in adipose tissue mass that occurs throughout life, yet the mechanism of adipocyte hyperplasia is unknown. We studied the potential of macrophage colony-stimulating factor (MCSF) to mediate adipocyte hyperplasia because of the profound effects MCSF exerts on pluripotent cell recruitment and differentiation in other tissues. We found that MCSF mRNA and protein were expressed by human adipocytes and that adipocyte MCSF expression was upregulated in rapidly growing adipose tissue that encircled acutely inflamed bowel and in adipose tissue from humans gaining weight (4-7 kg) with overfeeding. Localized overexpression of adipocyte MCSF was then induced in rabbit subcutaneous adipose tissue in vivo using adenoviral-mediated gene transfer. Successful overexpression of MCSF was associated with 16-fold increases in adipose tissue growth compared with a control adenovirus expressing beta-galactosidase. This occurred in the absence of increased cell size and in the presence of increased nuclear staining for MIB-1, a marker of proliferation. We conclude that MCSF participates in adipocyte hyperplasia and the physiological regulation of adipose tissue growth.
Adenoviridae↗
Direct cloning of DNA that interacts in vivo with a specific protein: application to RNA polymerase II and sites of pausing in Drosophila.
A new method is described for cloning DNA sequences occupied by a specific protein on chromatin in vivo . The approach uses UV cross-linking to couple proteins covalently to DNA and the resulting complexes are then purified under stringent conditions. Particular adducts are immunoprocipitated with antibody to the protein of interest. The resulting DNA (iDNA) is amplified by PCR, cloned and characterized. The model system used was RNA polymerase II (Pol II), whose density on particular DNAs under various conditions is well documented. Pol II can exist in several states on DNA. While Pol II can simply be bound to DNA, the bulk of DNA-associated Pol II is transcriptionally engaged in either the transcribing or paused states. Paused Pol IIs that have previously been characterized are found at promoters and have the distinctive property that their transcription in isolated nuclei is stimulated by sarkosyl or high salt. Here we isolate and sequence DNAs that cross-link to Pol II molecules. We identify by nuclear run-on assays those DNAs that have Pol II engaged in transcription. Twenty one percent of the iDNA clones that have detectable transcriptionally engaged Pol II appear to be paused, in that they display sarkosyl-stimulated trancription in a nuclear run-on transcription assay. At least some of these map to the 5'-ends of genes. These results suggest that transcriptional pausing of Pol II is a general phenomenon in vivo.
Animals↗
ABC of palliative care. Non-malignant conditions.
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Deglutition Disorders↗
Systematic evaluation of distribution of transgene expression after adenovirus-mediated gene transfer to the transplanted heart.
In the transplantation setting, the study and potential treatment of acute and chronic rejection by means of gene therapy will require widespread transgene expression in the donor organ. The distribution of transgene expression after adenovirus-mediated gene transfer via the coronary vasculature in a model of abdominal heterotopic heart transplantation in syngeneic rats (n = 6) was evaluated at 1 week. Reporter gene expression was evenly distributed in the base, the midventricle, and the apex of the transplanted hearts. This study demonstrates that intracoronary administration of the adenoviral vector to the donor heart results in widespread transgene expression.
Adenoviridae↗
Transbronchial gene transfer of endothelial nitric oxide synthase to transplanted lungs.
BACKGROUND: Experiments were designed to study the efficiency, distribution, and toxicity of transbronchial adenoviral-mediated transfer of endothelial constitutive nitric oxide synthase (ecNOS) gene to transplanted lungs. METHODS: Syngeneic orthotopic single-lung transplantation in the rat was performed after airway administration (300 microL, 1 x 10(9) pfu/mL) of either the ecNOS gene or the marker gene beta-Gal (control group) to donor lungs (n=4 each). After 4 days, transgene expression, inflammation, and the presence of apoptosis in the transplanted lungs were assessed by molecular, immunohistochemical, and histologic techniques. RESULTS: Gene transfer was confirmed by a positive polymerase chain reaction signal for the recombinant ecNOS gene, and recombinant messenger RNA by reverse transcription polymerase chain reaction. Positive immunohistochemical staining for ecNOS was present in more than 75% of pneumocytes only in ecNOS transduced lungs. Calcium-dependent nitric oxide synthase activity was increased in ecNOS- compared with betaGal-transduced lungs (2,139+/-756 versus 47+/-28 pmol x mg protein(-1) x h(-1); p < 0.05). Minimal to mild inflammation was observed in all transplanted lungs; fewer than 0.5% of cells in both groups were apoptotic. CONCLUSIONS: Transbronchial transfer of ecNOS gene to the transplanted lung results in transduction of pneumocytes with expression of a functionally active transgene product.
Adenoviridae↗
Ex vivo gene transfer of endothelial nitric oxide synthase to atherosclerotic rabbit aortic rings improves relaxations to acetylcholine.
Cholesterol feeding results in impaired endothelium dependent vasorelaxation. The role of nitric oxide in this process is unclear. The aim of this study was to evaluate the role of nitric oxide in cholesterol-induced vasomotor dysfunction by examining the effect of overexpression of eNOS in the hypercholesterolemic rabbit aorta on vascular reactivity. Vascular rings from the thoracic aorta of hypercholesterolemic rabbits were exposed ex vivo either to an adenoviral vector encoding endothelial nitric oxide synthase (AdeNOS) or Escherichia coli beta Galactosidase (AdbetaGal). Transgene expression was examined by histochemistry for beta galactosidase, immunohistochemistry for eNOS and cyclic GMP measurements and vasomotor studies were performed. Transgene expression was found to localize to the endothelium and adventitia. cGMP levels were significantly greater in AdeNOS compared to AdbetaGal transduced rings. Acetylcholine mediated relaxation was significantly impaired in cholesterol fed rabbits and was markedly improved by overexpression of eNOS. These results suggest that reduced NO bioavailability observed in cholesterol-induced vascular dysfunction can be partially overcome by eNOS gene transfer.
Acetylcholine↗
Gene therapy in lung transplantation: effective gene transfer via the airways.
OBJECTIVES: Gene therapy may provide a means of modifying factors that contribute to the development of pathologic processes in transplanted lungs. Experiments were designed to study the feasibility of adenovirus-mediated gene transfer by way of the airways to the transplanted lung. METHODS: Orthotopic left lung transplantation (Lewis to Lewis rats) was performed on four groups of animals. 300 microl of adenovirus solution encoding for beta-galactosidase was infused into the left bronchus of donor rats at viral concentrations of 10(8) pfu/ml (n = 5), 10(9) pfu/ml (n = 6), and 10(10) pfu/ml (n = 6), and the lung was ventilated for 5 minutes. Controls (n = 6) received medium only. Seven days after transplantation, native and transduced, transplanted lungs were harvested. Sections of lung were fixed and stained with a solution of X-Gal (5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside) and staining was evaluated for distribution by cell type and intensity. RESULTS: Beta-galactosidase expression was absent in the control group and in the native lungs. Two of five lungs in the 10(8) group expressed beta-galactosidase, but in a limited distribution and intensity. All six lungs in the 10(9) group and five of six lungs in the 10(10) group expressed beta-galactosidase. The distribution and intensity of beta-galactosidase expression ranged from only a few cells staining per slide to up to 75%. Pneumocytes were the most frequently stained cell type followed by alveolar macrophages. CONCLUSIONS: Gene transfer to the transplanted lung via the bronchial route is feasible and offers a novel technique to modify pathologic processes in the transplanted lung.
Adenoviridae↗
Transfer and expression of recombinant nitric oxide synthase genes in the cardiovascular system.
Gene therapy involves the transfer of a functional gene into host cells to correct the malfunction of a specific gene or to alleviate the symptoms of a disease. For gene transfer to the cardiovascular system, adenoviral vectors are the most efficient means of transfer. Recently, transfer and functional expression of recombinant nitrio oxide synthase (NOS) genes to cerebral and cardiovascular beds have been demonstrated both ex vivo and in vivo. Here, Alex Chen and colleagues review current progress in the field of vascular NOS gene transfer and the potential use of NOS gene therapy for a number of cardiovascular diseases. Although the feasibility of the NOS gene transfer approach has been demonstrated in animal models, currently available vectors have a number of technical and safety limitations that have to be solved before human NOS gene therapy for cardiovascular disease can be attempted.
Animals↗
Influence of temperature on adenovirus-mediated gene transfer.
OBJECTIVE: The transfer of recombinant genes to donor organs may allow for novel therapeutic approaches to the challenges of acute and chronic rejection. Adenoviral vectors are capable of efficient gene transfer, but use of these vectors during donor organ preservation may be less efficient due to the low temperature. This study was designed to examine the effect of temperature on the efficiency of adenovirus-mediated gene transfer. METHODS: Gene transfer to human endothelial cells, porcine vascular smooth muscle cells and cultured rat thoracic aortas was examined. Incubation with an adenoviral vector encoding for E. coli beta-galactosidase was performed for 1 h at three different temperatures: 4 degrees C, 10 degrees C and 37 degrees C. Transgene expression was assessed by histochemical staining for beta-galactosidase in transduced cells and by evaluation of beta-galactosidase activity in organ cultures. RESULTS: Both in human endothelial cells and vascular smooth muscle cells the percentage of positively staining cells following transduction at 37 degrees C was significantly greater than at 4 degrees C and at 10 degrees C (30.55 +/- 7.26% vs. 14.29 +/- 3.79% and 12.43 +/- 2.47%, respectively for endothelial cells, P < 0.01 vs. 4 degrees C and 10 degrees C; and 28.25 +/- 4.52% vs. 17.91 +/- 3.76% and 16.63 +/- 3.92%, respectively for smooth muscle cells, P < 0.05 vs. 4 degrees C, P < 0.01 vs. 10 degrees C). Beta-galactosidase activity was significantly greater in aortas transduced at 37 degrees C than in vessels transduced at 4 degrees C and 10 degrees C (289,700 +/- 113,300 vs. 149,600 +/- 54,390 and 108,800 +/- 23,140 relative chemiluminesce units/mg of total protein, respectively; P < 0.05 vs. 4 degrees C, P < 0.001 vs. 10 degrees C). CONCLUSIONS: The present study demonstrates that the efficiency of adenovirus-mediated gene transfer is significantly reduced at lower temperatures. The need for cold preservation of donor organs may render efficient adenovirus-mediated gene transfer more difficult in the transplantation setting.
Adenoviridae↗
Functional analysis of the human TAFII250 N-terminal kinase domain.
The largest subunit of the human transcription factor TFIID, TAFII250, was previously reported to contain serine/threonine kinase domains that can autophosphorylate and transphosphorylate the large subunit of the basal factor TFIIF. Here, we identify the regions of the N-terminal kinase domain (amino acids 1-414) necessary for kinase activity and examine its function in vivo. Point mutations within two patches of amino acids in the kinase domain decrease both autophosphorylation and transphosphorylation activities. Importantly, we find that TAFII250-bearing mutations within the N-terminal kinase domain exhibit a significantly reduced ability to rescue ts13 cells that express a temperature-sensitive TAFII250. Moreover, transcription from the cyclin A and cdc2 promoters becomes impaired when cotransfected with hTAFII250 containing inactive forms of the N-terminal kinase domain. Our results suggest that the TAFII250 kinase activity is required to direct transcription of at least some genes in vivo.
Cell Line↗