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Biomedical subjects

G Nelson

Publications and source records attributed to G Nelson.

At least 55 records · Page 3Linked to original sources

Factors associated with intention to undergo annual prostate cancer screening among African American men in Philadelphia.

BACKGROUND: This study assesses whether African American men in Philadelphia are receptive to annual prostate cancer screening. Factors associated with intention to undergo prostate cancer screening are also identified. METHODS: The authors randomly selected 218 African American men from the patient population of a large primary care practice in Philadelphia. The men were 40 to 70 years of age and were available for a telephone survey. Responses to survey items defined by the Preventive Health Model were collected from 154 respondents (71%). Univariate and multivariate analyses of screening intention were performed using survey data on sociodemographic background and medical history; knowledge, attitudes, and beliefs about prostate cancer and screening; social support and influence; and, intention to undergo a screening examination. RESULTS: Overall, 69% of subjects reported that they intended to have annual prostate cancer screening. Logistic regression analyses showed that subject belief in screening efficacy (P=0.0002) were positively and significantly associated with intention to screen. CONCLUSIONS: Findings reported here show that African American men in an urban primary care practice setting are receptive to annual prostate cancer screening and that psychologic and social influence factors are associated with screening intention. The data highlight the need for health care professionals to provide education and advice regarding prostate cancer care to men in this population.

Adult↗

Social networks, social support, personal empowerment, and the adaptation of psychiatric consumers/survivors: path analytic models.

In this paper, we examine the relationships between social network characteristics, personal empowerment, social support, and adaptation of psychiatric consumer/survivors. Using path model analyses, we found that: (1) personal empowerment had statistically significant direct effects on positive affect, meaningful activity, and negative affect; (2) positive social support mediated the relationship between the proportion of women in consumer/survivors' networks and positive affect and meaningful activity; and (3) negative social interaction mediated the relationship between consumer/survivors' gender and negative affect. The results point out the importance of gender effects in social support processes, the differential association between type of social interaction (positive vs negative) and adaptation indices (positive vs negative), and the importance of personal empowerment for consumer/survivors' adaptation. We discuss the findings in terms of their implications for further research and community-based housing programmes for psychiatric consumer/survivors.

Adaptation, Psychological↗

Benzo[b]fluoranthene: tumorigenicity in strain A/J mouse lungs, DNA adducts and mutations in the Ki-ras oncogene.

The polycyclic aromatic hydrocarbon benzo[b]fluoranthene (B[b]F) is a pervasive constituent of environmental combustion products. We sought to examine the lung tumorigenic activity of B[b]F in strain A/J mice, to study the relationship between formation and decay of B[b]F-DNA adducts and to examine mutations in the Ki-ras proto-oncogene in DNA from B[b]F-induced tumors. Mice were given i.p. injections of 0, 10, 50, 100 or 200 mg/kg body wt and lung adenomas were scored after 8 months. B[b]F induced significant numbers of mouse lung adenomas in a dose-related fashion, with the highest dose (200 mg/kg) yielding 6.95 adenomas/ mouse, with 100% of the mice exhibiting an adenoma. In mice given tricaprylin, the vehicle control, there were 0.60 adenomas/mouse, with 55% of the mice exhibiting an adenoma. Based on dose, B[b]F was less active than benzo[a]pyrene. DNA adducts were analyzed qualitatively and quantitatively by 32P-post-labeling in lungs of strain A/J mice 1, 3, 5, 7, 14 and 21 days after i.p. injection. Maximal levels of adduction occurred 5 days after treatment with the 200 mg/kg dose group, producing 1230 amol B[b]F-DNA adducts/microgram DNA. The major B[b]F-DNA adduct was identified by co-chromatography as trans-9, 10-dihydroxy-anti-11, 12-epoxy-5-hydroxy-9, 10, 11, 12-tetra-hydro-B[b]F-deoxyguanosine. Approximately 86% of the tumors had a mutation in codon 12 of the Ki-ras oncogene, as determined by direct DNA sequencing of PCR-amplified exon 1 and single-stranded conformation polymorphism analysis. Analysis of the Ki-ras mutation spectrum in 25 of 29 B[b]F-induced tumors revealed the predominant mutation to be a G-->T transversion in the first or second base of codon 12, congruous with the DNA adduct data. Our data are consistent with previous reports in mouse skin implicating a phenolic diol epoxide as the proximate carcinogenic form of B[b]F that binds to guanine.

Animals↗

Radiation protection systems for the final focus test beam at SLAC.

The Final Focus Test Beam (FFTB) is a new beam line at the Stanford Linear Accelerator Center designed to test new beam optics concepts, hardware, and techniques necessary to achieve and measure the small spot sizes required for future generations of high-energy e+e- linear colliders. The FFTB takes a 47 GeVc-1, 1 kW electron beam at the end of the Stanford Linear Accelerator Center linear accelerator and transports it to the FFTB beam dump. A radiation protection system was designed and installed for the FFTB with the primary goal that the integrated dose equivalent outside the shielding resulting from beam loss would not exceed 10 mSv y-1. This system is comprised of shielding, a beam containment system and a personnel protection system. This paper presents various aspects of radiation safety at Stanford Linear Accelerator Center that were considered in the design of the FFTB radiation protection system. Beam tests were conducted in which the performance of various beam containment devices and the shielding effectiveness were evaluated. Preliminary results from these tests are presented.

California↗

Localized or systemic in vivo heat inactivation of human immunodeficiency virus (HIV): a mathematical analysis.

Temperatures > or = 42 degrees C, maintained for > or = 25 min, inactivate approximately 25% of human immunodeficiency virus (HIV). HIV-infected T cells are more sensitive to heat than healthy lymphocytes, and susceptibility increases when the cells are presensitized by exposure to tumor necrosis factor. Thus, induction of a whole-body hyperthermia or hyperthermia specifically limited to tissues having a high viral load is a potential antiviral therapy for acquired immunodeficiency syndrome (AIDS). Accordingly, we incorporated therapeutic hyperthermia into an existing mathematical model that evaluates the interaction between HIV and CD4+ T cells. Given the assumptions and limitations of this model, the results indicate that a daily therapy lowering the population of actively infected cells by 40% or infectious virus by 40% would effectively reverse the depletion of T cells. In contrast, a daily decline of 20% of either actively infected cells or infectious virus would have a marginal effect. However, daily reduction by 20% of both actively infected cells and infectious virus could restore T-cell numbers, assuming that permanent damage had not been inflicted on the thymus. Since daily treatments would probably be excessively stressful, whole-body hyperthermia seems unlikely to be clinically useful. In contrast, heating directed specifically to areas of viral concentration may be effective and have a suitable risk/benefit ratio.

CD4 Lymphocyte Count↗

A multivariate analysis of mental hospital recidivism.

This study identifies health problems, instrumental activities of daily living, employment status, and number of previous admissions as significant factors of recidivism to a mental health residential facility. The study, conducted over a 5-year period, includes measures on 32 predictor variables collected either on admission, on discharge, or 12-15 months following discharge or on readmission. The study's results are interpreted in light of current changes in the mental health service delivery system including the interactive role of physical and mental illnesses, expanding access to community-based generic services, focusing on functional skills and their development or remediation, and the changing criteria for measuring mental health effectiveness.

Catchment Area, Health↗

The total costs of illness: a metric for health care reform.

Systems thinking is a fundamental element of quality management and should be a fundamental element of health care reform. An implication of systems thinking is that one aim of health care should be to minimize the total costs of illness, not simply the direct medical expenditures. If we are to continue to improve health care over time, we should measure its impact on the total costs of illness to the patient, family, employer, and society. Thus a system of measurement is needed that quantifies total costs of illness and also suggests how these constituencies can collaborate to improve processes and reduce total costs. This article introduces the total costs of illness concept, contrasts it with societal costs of illness, describes a measurement system we developed to quantify it, and describes a case study examining the total costs of back injury illness to employers. We found that medical expenditures accounted for less than half of the total costs of illness, the average total costs of illness varied by over 350 percent among employers, and a simple metric (days off work) explained 62.5 percent of the variance in total costs of illness.

Accidents, Occupational↗

The development of a mental health coalition: a case study.

Described the development of a local-level mental health coalition to advocate for housing and community support programs for psychiatric consumer/survivors. Resource mobilization theory was used as a framework from which to view and understand the origins, goals, tactics, and outcomes of the coalition. Data were presented indicating that the coalition played a role in obtaining increased funding for housing and community support programs. Also, there was an emphasis on consumer/survivor and family participation in the change process. Benefits and limitations of the coalition after 6 years of operation were reviewed and compared with other advocacy coalitions in mental health.

Community Mental Health Services↗

Emotional well-being of separated and married women: long-term follow-up study.

Separated and married women were studied longitudinally. Recently separated women reported more growth-oriented coping and positive life changes than did married women, but no significant differences were evident six years later. Life strains at early time intervals predicted emotional well-being at the last time interval, and coping served a stress-buffering function over time.

Adaptation, Psychological↗

Morphological transformation and DNA adduct formation by dibenz[a,h]anthracene and its metabolites in C3H10T1/2CL8 cells.

The major routes of metabolic activation of dibenz[a,h]-anthracene (DBA) have been studied in transformable C3H10T1/2CL8 (C3H10T1/2) mouse embryo fibroblasts in culture. The morphological transforming activities of three potential intermediates formed by metabolism of DBA by C3H10T1/2 cells, trans-3,4-dihydroxy-3,4-dihydro-DBA-(DBA-3,4-diol), trans-dihydroxy-3,4-dihydro-DBA-anti-1,2-oxide (DBA-3,4-diol-1,2-oxide) and DBA-5,6-oxide were determined. DBA-3,4-diol-1,2-oxide was a strong morphological transforming agent giving a mean of 73% dishes with Type II or III foci and 1.63 Type II and III foci per dish at 0.5 microgram/ml. DBA-3,4-diol produced a mean of 42% dishes with Type II or III foci and 0.81 Type II and III foci per dish at 2.5 micrograms/ml. DBA gave a mean of 24% dishes with Type II or III foci and 0.29 Type II and III foci per dish at 2.5 micrograms/ml. DBA-5,6-oxide was found to be inactive. DNA adducts of DBA, DBA-3,4-diol, DBA-3,4-diol-1,2-oxide, DBA-1,4/2,3-tetrol and DBA-5,6-oxide in C3H10T1/2 cells were analyzed by 32P-postlabeling method. DBA gave 11 adducts, nine of which were observed in the DNA of cells treated with DBA-3,4-diol and seven from cells treated with DBA-3,4-diol-1,2-oxide. Two of these adducts that appear in each of the treatment groups have been identified as the product of the interaction of DBA-3,4-diol-1,2-oxide with 2'-deoxyguanosine. Furthermore, there is evidence for DBA-DNA adducts in cells treated with DBA, DBA-3,4-diol and DBA-3,4-diol-1,2-oxide arising from metabolism to (+,-)-trans,trans-3,4,10,11-tetrahydroxy-3,4,10,11-tetrahydro-DBA (DBA-3,4,10,11-bis-diol). These results are based on co-migration of C3H10T1/2 DNA adducts with skin DNA adducts formed after topical treatment of mice with DBA-3,4,10,11-bis-diol. In C3H10T1/2 cells, DBA is metabolically activated through DBA-3,4-diol, which is further activated via the DBA-3,4-diol-1,2-oxide and DBA-3,4,10,11-bis-diol pathways. No evidence is provided for the metabolism of DBA by the K-region pathway.

Animals↗

Cyclopenta[cd]pyrene-induced tumorigenicity, Ki-ras codon 12 mutations and DNA adducts in strain A/J mouse lung.

Cyclopenta[cd]pyrene (CPP) is a ubiquitous cyclopenta-fused polycyclic aromatic hydrocarbon. CPP is highly genotoxic in bacterial and mammalian systems inducing gene mutations, sister chromatid exchanges and morphological transformation. CPP is a mouse skin carcinogen, a mouse skin tumor initiator and induces pulmonary tumors in newborn mice. We have examined the tumorigenic activity of CPP in strain A/J mice, have determined the formation and persistence of CPP-induced DNA adducts in lung tissue, and analyzed the mutational spectrum in the Ki-ras oncogene from CPP-induced tumors. CPP dissolved in tricaprylin was administered by i.p. injection to male A/J mice (20 mice/dose) at 0, 10, 50, 100 and 200 mg/kg. Animals were killed 8 months later and the lungs removed, fixed, and surface adenomas enumerated. CPP proved to be highly tumorigenic in A/J mice in terms of inducing lung adenomas. The observed tumor multiplicities (lung adenomas/mouse) were: 97.7 +/- 28.7 at 200 mg/kg, 32.8 +/- 15.4 at 100 mg/kg, 4.63 +/- 2.11 at 50 mg/kg and 0.58 +/- 0.82 at 10 mg/kg. Tricaprylin-treated controls produced 0.60 +/- 0.58 lung adenomas/mouse. Groups of mice treated under the same dosing conditions as those in the tumor studies were killed 1, 3, 7, 14 and 21 days after treatment. The lungs were removed, and the DNA was subjected to DNA adduct analysis by the 32P-postlabeling method. Total CPP-DNA adducts in mouse lung peaked at day 3 with 5870 amol CPP adducts/micrograms DNA after a single dose of 200 mg/kg. DNA adduct levels decreased to 1800 amol CPP adducts/micrograms DNA at day 21. Qualitative DNA adduct analysis revealed four major adducts and one minor adduct. Co-chromatography of the lung DNA from CPP-treated mice with calf thymus DNA treated with CPP-3,4-oxide indicated that all DNA adducts were oxide derived and comparison with CPP-3,4-oxide-treated polydeoxyguanylic acid suggests that almost all of these adducts are CPP-3,4-oxide-2'-deoxyguanosine adducts. Ki-ras codon 12 mutation analysis of the DNA from tumors taken from the 100 and 200 mg/kg CPP dose groups demonstrated the following patterns: GGT-->CGT (50%); GGT-->GTT (15%); GGT-->TGT (25%); GGT-->GAT (10%). We conclude that CPP is highly tumorigenic in the A/J mouse lung adenoma model, being five times more active than benzo[a]pyrene. This is unlike the result of CPP as a mouse skin tumorigen or tumor initiator in which CPP is considerably less potent than benzo[a]pyrene.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenoma↗

Life event stress and myocardial reinfarction: a prospective study.

Earlier studies of life event stress in coronary heart disease (CHD) have been flawed by cross-sectional design and inadequate methods for assessing life-event stress. This 3-year prospective study of acute myocardial infarct (AMI) patients reveals significant independent associations between acute and chronic stressors at first admission, and risk of recurrent AMI and death, occurring in the 3 years of follow-up. Relative risks of reinfarction (or death from reinfarction) in the entire sample, for acute events and chronic difficulties were, 2.5 and 2.3 respectively and were statistically significant. When subjects admitted with first AMI were considered alone, relative risks were 3.1 and 4.1 respectively. The clinical significance of these findings is discussed.

Adult↗

Modulation of cellular macromolecular synthesis by coronavirus: implication for pathogenesis.

Infection with the murine coronavirus strain JHM decreases cell surface expression of major histocompatibility complex class I antigens. Northern blots showed that JHM virus infection rapidly reduced the level of actin mRNA, whereas the levels of major histocompatibility complex class I and tubulin mRNAs were reduced only slightly. By contrast, the mRNA levels of interleukin 1 beta, colony-stimulating factor 1 receptor, and tumor necrosis factor alpha increased following infection.

Actins↗

Fatty acid profiles of major food sources of howler monkeys (Alouatta palliata) in the neotropics.

Wild howler monkeys (Alouatta palliata) get most of their calories from carbohydrates (65%) and fats (18%) of native tropical plants, but little is known about their intake of individual fatty acids. The fatty acid composition of several natural food sources of howler monkeys collected in Panama was determined by gas-liquid chromatography. The predominant fatty acids were palmitic (30%), linoleic (23%), alpha-linolenic (16%) and oleic (15%). Fatty acids with less than 16, and more than 18, carbon chains were uncommon (0-7%). Although total saturated fatty acids were high in some specific food sources (22-54% of total fatty acids and 8 energy %), most of the calories from fat in the animals' diets are derived from mono- and polyunsaturated fatty acids (9.75 energy %). All food sources had significant amounts of the omega-3 fatty acid, alpha-linolenic acid (2.9 energy %). In terms of human diets, the howler monkey's fat consumption would not be considered atherogenic. Unless these animals show a particular adverse susceptibility to dietary fat, it is unlikely that their fat intake is the primary cause of the low, but significant, incidence of atherosclerosis that develops in these animals in the wild state.

Alouatta↗