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Biomedical subjects

G Nelson

Publications and source records attributed to G Nelson.

At least 37 records · Page 2Linked to original sources
PubMed1999

FIGO stage IIIC endometrial carcinoma with metastases confined to pelvic lymph nodes: analysis of treatment outcomes, prognostic variables, and failure patterns following adjuvant radiation therapy.

OBJECTIVES: This study was undertaken to evaluate the prognostic significance of isolated positive pelvic lymph nodes on survival and to analyze other prognostic variables, overall survival, and failure patterns in surgically staged endometrial carcinoma patients with positive pelvic lymph nodes and negative para-aortic lymph nodes following radiation therapy (RT). METHODS: Between January 1, 1987, and December 31, 1997, 782 women underwent primary treatment for uterine cancer at Indiana University Medical Center. Through a review of the medical records, we identified 58 patients with pathologic stage IIIA, 27 patients with pathologic stage IIIB, and 77 patients with pathologic stage IIIC endometrial carcinoma. Patients with pathologically positive or unsampled para-aortic lymph nodes and patients who received preoperative radiation therapy were excluded, leaving a study group of 17 patients with nodal metastases confined to pelvic lymph nodes. Thirteen patients received adjuvant pelvic RT using AP-PA or four-field technique. A median dose of 5040 cGy was delivered. Four patients received whole abdominal irradiation (WAI) delivering a median dose of 3000 cGy. Two patients received vaginal cuff boosts of 1000 and 3560 cGy to 0.5 cm from the vaginal surface mucosa via Cs-137 brachytherapy. Two patients also received adjuvant chemotherapy (cis-platinum and doxorubicin) and/or hormonal therapy (megestrol acetate). Disease-free and overall survivals were estimated using the Kaplan-Meier method of statistical analysis and prognostic variables were analyzed using the log-rank test. RESULTS: With a median follow-up of 51 months the actuarial 5-year disease-free survival was 81% and the actuarial 2-year and 5-year overall survival rates were 81 and 72%, respectively. Univariate analysis revealed that positive peritoneal cytology in conjunction with positive pelvic lymph nodes imparts a greater risk of recurrence and decreased overall survival. There were no pelvic and/or upper abdominal failures, but there were recurrences in the para-aortic lymph nodes (two patients) and distantly (two patients). CONCLUSION: Surgery followed by postoperative pelvic RT is a viable treatment option for pathologically staged stage IIIC endometrial carcinoma with disease confined to the pelvic lymph nodes. Failures in the para-aortic region suggest a possible role for extended-field RT. Patients with positive peritoneal cytology in conjunction with nodal metastasis fared poorly with pelvic RT. Studies evaluating the efficacy of WAI are ongoing. Finally, substages within FIGO stage IIIC are recommended in an effort to better understand and define treatment strategies which might be appropriate for these patients.

Actuarial Analysis↗
PubMed1999

Radiation safety system of the B-Factory at the Stanford Linear Accelerator Center.

The radiation safety system of the B-Factory accelerator facility at the Stanford Linear Accelerator Center is described. The radiation safety system, which is designed to protect people from prompt radiation exposure due to beam operation, consists of the access control system and the radiation containment system. The access control system prevents people from being exposed to the very high radiation levels inside a beamline shielding enclosure. The access control system consists of barriers, a standard entry module at every entrance, and beam stoppers. The radiation containment system prevents people from being exposed to the radiation outside a shielding enclosure due to either normal or abnormal operation. The radiation containment system consists of power limiting devices, shielding, dump and collimator, and an active radiation monitoring system. The inter-related elements for the access control system and radiation containment system, as well as the associated interlock network, are described. The policies and practices used in establishing the radiation safety system are also compared with the regulatory requirements.

California↗
PubMed1999

Intra-arterial Cereport (RMP-7) and carboplatin: a dose escalation study for recurrent malignant gliomas.

OBJECTIVE: Animal and human studies have shown increased delivery of radiolabeled compounds across the blood-brain-tumor barrier using intra-arterial (IA) Cereport (RMP-7; Alkermes Inc., Cambridge, MA) with a radiolabeled tracer. This present study assesses the safety, tolerance, and preliminary efficacy of the IA administration of carboplatin with Cereport. METHODS: An open-label dose escalation study of IA Cereport (10-300 ng/kg) with 100 mg of IA carboplatin was conducted in 11 patients with recurrent malignant gliomas and 1 patient treated adjuvantly after radiation therapy. Tumor size and laboratory and clinical statuses were assessed. RESULTS: Adverse events were mainly neurological in nature and corresponded to the anatomic location of the tumor. Karnofsky performance scale scores did not decline, overall, for those patients who had tumor response. Tumor shrinkage was observed in three of six evaluable patients who received a dose of 300 ng/kg with durable responses of 60, 64, and 106+ weeks. CONCLUSION: Previous studies have demonstrated increased permeability in human gliomas using IA Cereport. This study demonstrates durable imaging responses using 100 mg of IA carboplatin in combination with Cereport. The drug combination in this patient population seems to be safe and acceptable, providing a novel means of antitumor dose intensification.

Adult↗
PubMed1999

From housing to homes: a review of the literature on housing approaches for psychiatric consumer/survivors.

In this paper, we review the literature on housing for psychiatric consumer/survivors since the publication of the Nelson and Smith Fowler (1987) review more than a decade ago. First, we review research and propose a definition to contrast key features of three approaches to housing: (a) custodial, (b) supportive, and (c) supported. Second, we examine studies of the relationships between the characteristics of housing and adaptational outcomes for residents (e.g., personal empowerment). Third, we review studies which have examined out-comes for residents for these three different housing approaches. We conclude by critically reflecting on the values and research of the different approaches to housing, to make recommendations for future policy and planning, practice, and research.

Custodial Care↗
PubMed1999

Organizational change towards the empowerment-community integration paradigm in community mental health.

As a part of a larger study of change towards the values of an empowerment-community integration paradigm in community mental health, we examined changes in 3 mental health organizations in 1 community. Using qualitative methods, we focused on: (a) change pathways, (b) organizational change outcomes, and (c) the factors which helped and hindered change outcomes. We found evidence of a paradigm shift in the values and related practices within the organizations. Our results and themes are discussed and aimed at understanding and integrating knowledge about organizational change and the empowerment-community integration paradigm in community mental health.

Community Mental Health Services↗
PubMed1999

A quantitative comparison of dibenzo[a,l]pyrene-DNA adduct formation by recombinant human cytochrome P450 microsomes.

Dibenzo[a,l]pyrene (DB[a,l]P), an extremely potent environmental carcinogen, is metabolically activated in mammalian cells and microsomes through the fjord-region dihydrodiol, trans-DB[a,l]P-11, 12-diol, to syn- and anti-DB[a,l]P-11,12-diol-13,14-epoxides (syn- and anti-DB[a,l]PDEs). The role of seven individual recombinant human cytochrome P450s (1A1, 1A2, 1B1, 2B6, 2C9, 2E1, and 3A4) in the metabolic activation of DB[a,l]P and formation of DNA adducts was examined by using (32)P postlabeling, thin-layer chromatography, and high-pressure liquid chromatography. We found that, in the presence of epoxide hydrolase, only P450 1A1 and P450 1B1 catalyzed the formation of DB[a,l]PDE-DNA adducts and several unidentified polar adducts. Human P450 1A1 catalyzed the formation of DB[a, l]PDE-DNA adducts and unidentified polar adducts at rates threefold and 17-fold greater than did human P450 1B1 (256 fmol/h/nmol P450 versus 90 fmol/h/nmol P450 and 132 fmol/h/nmol P450 versus 8 fmol/h/nmol P450, respectively). P450 1A1 DNA adducts were derived from both anti- and syn-DB[a,l]PDE at rates of 73 fmol/h/nmol P450 and 51 fmol/h/nmol P450, respectively. P450 1B1 produced adducts derived from anti-DB[a,l]PDE at a rate of 82 fmol/h/nmol, whereas only a small number of adducts were derived from syn-DB[a,l]PDE (0.4 fmol/h/nmol). These results demonstrated the potential of human P450 1A1 and P450 1B1 to contribute to the metabolic activation and carcinogenicity of DB[a,l]P and provided additional evidence that human P450 1A1 and 1B1 differ in their stereospecific activation of DB[a,l]P. Mol. Carcinog. 26:74-82, 1999. Published 1999 Wiley-Liss, Inc.

Animals↗
PubMed1998

The relationship between housing characteristics, emotional well-being and the personal empowerment of psychiatric consumer/survivors.

In this research, we examine the relationships between the housing characteristics and dimensions of community adaptation for 107 psychiatric consumer/survivors. Hypotheses about which housing characteristics best predict which dimensions of adaptation were made based on previous research and theory. Using a longitudinal research design, we found, after controlling for demographic variables and prior adaptation, that the number of living companions, housing concerns, and having a private room all significantly predicted different dimensions of community adaptation. The findings partially support our theoretical expectations and illuminate the relationship between physical, social and organizational aspects of community-based housing and the adaptation of psychiatric consumer/survivors. We discuss the implications of the results for policy and practice in providing housing for this population.

Activities of Daily Living↗
PubMed1998

"Nothing about me, without me": participatory action research with self-help/mutual aid organizations for psychiatric consumer/survivors.

Participatory action research with self-help/mutual aid organizations for psychiatric consumer/survivors is reviewed. We begin by tracing the origins of and defining both participatory action research and self-help/mutual aid. In so doing, the degree of correspondence between the assumptions/values of participatory action research and those of self-help/mutual aid for psychiatric consumer/survivors is examined. We argue that participatory action research and self-help/mutual aid share four values in common: (a) empowerment, (b) supportive relationships, (c) social change, and (d) learning as an ongoing process. Next, selected examples of participatory action research with psychiatric consumer/survivor-controlled self-help/mutual aid organizations which illustrate these shared values are provided. We conclude with recommendations of how the key values can be promoted in both the methodological and substantive aspects of future participatory action research with self-help/mutual aid organizations for psychiatric consumer/survivors.

Humans↗
PubMed1998

Presentation, management and follow-up of Schilder's disease.

Schilder's diffuse myelinoclastic sclerosis is a rare demyelinating disease which often mimics intracranial neoplasm or abscess. We have treated 3 patients with this disorder in the past 5 years and followed their postoperative course. Certain distinct features of this disease will allow neurosurgeons to preoperatively entertain this diagnosis. We discuss postoperative treatment and propose a new hypothesis regarding the variable prognoses of this disorder. Schilder's disease constitutes an important diagnosis for any neurosurgeon to be aware of (especially those treating the pediatric age group) which has not received adequate coverage in the neurosurgical literature.

Adolescent↗
PubMed1998

Diurnal intraocular pressure curves in healthy rhesus macaques (Macaca mulatta) and rhesus macaques with normotensive and hypertensive primary open-angle glaucoma.

PURPOSE: The authors identify any diurnal intraocular pressure (IOP) variation in healthy Cayo Santiago macaques, as well as Cayo Santiago macaques with normotensive and hypertensive primary open-angle glaucoma (POAG), to further evaluate their potential value as a model for human POAG. METHODS: Twenty-four monkeys (eight animals each of the healthy control, normotensive glaucoma, and hypertensive glaucoma groups) were sedated with ketamine hydrochloride and the IOP measured hourly from 8:00 AM until 3:00 PM with a Tonopen XL applanation tonometer (Mentor, Norwell, MA, U.S.A.). Mean IOP time profiles, mean IOPs at each observation time, and linear trends in mean IOP over time were compared among groups. Intraocular pressure rate-of-change over time and residual variation about the regression line for each individual eye were analyzed. Cup/disc ratio (C/D) was compared with baseline IOP, IOP profile mean and slope, and IOP residual variation. RESULTS: A significant group and time effect on mean IOP (p = 0.0001 and 0.011, respectively), with highest values at 2:00 PM or 3:00 PM, and a significant increasing linear trend in mean IOP over time in the hypertensive group were observed (p = 0.012). Intermediate readings between control and hypertensive mean IOPs were identified for the normotensive glaucoma group. The biggest range of IOP variation was found in the hypertensive glaucoma monkeys. Higher variations in IOP did not lead to an increase in C/D. CONCLUSIONS: This study provides evidence that the Cayo Santiago macaques are a valuable model for human normotensive and hypertensive POAG.

Animals↗
PubMed1998

Respiratory health and immunological profile of poultry workers.

OBJECTIVES: To examine work-related respiratory symptoms in poultry workers, and to test for immunologically mediated responses to poultry-related agents. DESIGN: A cross-sectional survey of differentially exposed poultry workers and unexposed blue-collar workers. SETTING: Three poultry farms and a poultry plant in Gauteng (exposed workers) and a municipal workers' clinic in Johannesburg (controls). PARTICIPANTS: 134 poultry workers (85.4% of all eligible workers) and 122 controls (> 95% response rate). OUTCOME MEASURES: Respiratory symptoms plus allergy and hypersensitivity to poultry agents identified by skin-prick tests, and by the presence of specific IgE and IgG enzyme-linked immunoflow assay and nonspecific (radial immunodiffusion) antibodies. RESULTS: Smoking habits and atopic status were similar in the poultry workers and the controls. Symptoms were very common in poultry workers, for example work-related cough in 32% and work-related wheeze in 23% of highly exposed workers. Significantly more poultry workers than controls complained of chest symptoms (increasing with increasing exposure), and of eye, skin and nose irritation at work. More poultry workers than controls had symptoms consistent with asthma (e.g. 3%, 4%, 13% and 11% in controls and subjects with low, medium and high exposure, respectively), and symptom complexes associated with organic dust exposure. Five poultry workers had positive skin-prick test reactions to poultry-specific antigens, but none of the unexposed controls reacted. More poultry workers than controls had positive immunodiffusion test reactions to chicken feed, feathers and serum, and IgE to chicken faeces. There was no association between immunological status and respiratory symptoms. CONCLUSION: We found a very high prevalence of exposure-related symptoms in poultry workers; improved hazard control is strongly indicated. Tests of allergy and hypersensitivity were associated with exposure, but not with disease. The possibility of useful tests of sensitisation has not been excluded; a prospective study design is likely to be more rewarding than cross-sectional approaches such as in this study.

Air Pollutants, Occupational↗
PubMed1997

Flow-injection detector incorporating a screen-printed disposable amperometric biosensor for monitoring organophosphate pesticides.

The construction of a wall-jet flow cell, which houses a screen-printed amperometric pesticide biosensor, together with a complete flow-injection system, is described. This system was initially employed in studies to stabilise the enzyme acetylcholinesterase (AChE), which was immobilised on a cobalt phthalocyanine screen-printed carbon electrode to form a biosensor. A combination of dextran sulfate and lactitol, and carbodiimide for enzyme immobilisation, resulted in biosensor lifetimes of at least 76 d (at 37 degrees C). Flow-injection and biosensor conditions were optimised, then the system was evaluated by monitoring the model organophosphate pesticides (OP) dichlorvos and paraoxon. The detection limits were 7 x 10(-11) mol dm-3 (for 1 U of AChE) and 4 x 10(-11) mol dm-3 (for 0.05 U of AChE), respectively, which are better than for other electrochemical methods. Initial evaluations on two river water samples have been carried out to test the validity of the system for OP determination in field samples.

Biosensing Techniques↗
PubMed1997

Comparison of the morphological transforming activities of dibenzo[a,l]pyrene and benzo[a]pyrene in C3H10T1/2CL8 cells and characterization of the dibenzo[a,l]pyrene-DNA adducts.

C3H10T1/2CL8 (C3H10T1/2) mouse embryo fibroblasts were used to study the in vitro carcinogenic activities of dibenzo[a,l]pyrene (DB[a,l]P) and benzo[a]pyrene (B[a]P). The morphological transforming activities of these rodent carcinogens were compared using replicate concentration-response studies. In concentration ranges where both polycyclic aromatic hydrocarbons (PAHs) were active, DB[a,l]P proved to be four to 12 times as potent as B[a]P based on concentration. At lower concentrations DB[a,l]P was active at 0.10 and 0.20 microM, concentrations where B[a]P was inactive. This makes DB[a,l]P the most potent non-methylated PAH evaluated to date in C3H10T1/2 cells. DNA adducts of DB[a,l]P in C3H10T1/2 cells were analyzed by both TLC and TLC/HPLC 32P-postlabeling methods using mononucleotide 3'-phosphate adduct standards derived from the reactions of anti-DB[a,l]P-11,12-diol-13,14-epoxide (anti-DB[a,l]PDE) and syn-DB[a,l]P-11,12-diol-13,14-epoxide (syn-DB[a,l]PDE) with deoxyadenosine 3'-monophosphate and deoxyguanosine 3'-monophosphate. All of the DNA adducts observed in C3H10T1/2 cells treated with DB[a,l]P were identified as being derived from the metabolism of DB[a,l]P to its fjord region diol epoxides through DB[a,l]P-11,12-diol. The predominant adduct was identified as an anti-DB[a,l]PDE-deoxyadenosine adduct. Other major adducts were anti-DB[a,l]PDE-deoxyguanosine and syn-DB[a,l]PDE-deoxyadenosine adducts with minor amounts of syn-DB[a,l]PDE-deoxyguanosine adducts. These DNA adduct data are consistent with similar findings of DB[a,l]PDE-deoxyadenosine adducts in mouse skin studies and human mammary cells in culture.

Animals↗
PubMed1997

Intracarotid infusion of RMP-7, a bradykinin analog, and transport of gallium-68 ethylenediamine tetraacetic acid into human gliomas.

The bradykinin analog, RMP-7, was investigated for its ability to increase selectively the transport of 68Ga ethylenediamine tetraacetic acid (EDTA) into recurrent malignant gliomas in nine patients. For each patient, two position emission tomography (PET) studies (one with and one without RMP-7) were performed. For studies with RMP-7, 10 to 300 ng/kg of the compound was infused into the supraophthalmic carotid artery over 15 minutes. In each PET study, a sequence of PET scans was initiated simultaneously with an intravenous bolus of 68Ga EDTA (5-10 mCi). Arterial samples were taken to provide the input function. All PET scans were coregistered to the magnetic resonance (MR) images of the patient. Regions of interest were defined for tumor and normal tissue regions on MR images and were copied to the coregistered PET dynamic images to provide brain tissue-time activity curves. The constant (Ki) for the transport of gallium-68 from plasma to brain tissue was determined using a simple compartmental model. Intracarotid infusion of RMP-7 significantly increased transport into tumor regions with an average increase of 46 +/- 42% (mean +/- standard deviation, p < 0.05). Permeability in normal tissue regions was not significantly increased. Tumors in three of six patients treated with 300 ng/kg RMP-7 and carboplatin had at least a 50% reduction in tumor volume as measured by MR imaging. Intracarotid infusion of RMP-7 is a novel technique for selective delivery of antitumor compounds into brain tumors.

Adult↗