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Biomedical subjects

G Nelson

Publications and source records attributed to G Nelson.

At least 19 recordsLinked to original sources
PubMed1992

Vaccines against coxiellosis and Q fever. Development of a chloroform:methanol residue subunit of phase I Coxiella burnetti for the immunization of animals.

We have demonstrated the safety, immunogenicity, and efficacy of the WC and CMR vaccines in guinea pigs. Vaccination of guinea pigs with either WC or CMR protects animals against challenge with virulent C. burnetii. A total of 2 micrograms of either WC or CMR vaccine was a significant priming dose. A total of 20 micrograms gave complete protection against lethal challenge. Detection of antibodies to phase II cells by microaglutination, after vaccination with either WC or CMR and before lethal challenge, correlated with the ability of guinea pigs to mount a protective immune response. The PD50 values for WC and CMR vaccines, administered as a single dose, were 0.3 and 1.4 micrograms per animal, respectively. In contrast, the PD50 values for the WC and CMR vaccines, administered as two doses, were 0.83 and 0.72 micrograms per animal, respectively. Although the PD50 values for the two vaccines are similar, the CMR vaccine is preferred over the WC vaccine because it induces significantly fewer adverse reactions, and repeat injections can be given. Unvaccinated guinea pigs do not clear infectious microorganisms after challenge infection. Vaccination before challenge infection reduces the infectious load of C. burnetti in the blood and in various organs of the animals. When vaccinated animals were challenge infected and treated with rifampicin, the microorganisms were not eliminated from various organs. However, the combination of vaccination, challenge, and rifampicin treatment is effective in reducing the number of infectious microorganisms in some of these sites. We have demonstrated the safety and immunogenicity of the CMR vaccine in sheep and goats. Animals that were seropositive for one or more antigens developed significant levels of antibodies to alternate antigens, but no adverse reactions were observed at the site of s.c. injection of the CMR vaccine. This demonstrates that seropositive animals can be successfully immunized with this vaccine. These results also indicate that a long-term vaccination program using the CMR vaccine has the potential for producing animals with significant antibody titers to C. burnetii and perhaps lifelong immunity. The goal of a Q fever vaccination program is to produce immunized animals that are able to clear completely the infectious microorganisms. The appropriate vaccination schedule to render adult animals and their offspring "Q fever-free" should now be thoroughly investigated.

Animals↗
PubMed1992

Social network transactions of psychiatric patients.

In this research we examine self-reported social network transactions of former psychiatric inpatients residing in different types of housing in the community. Unlike earlier research, we found considerable reciprocity in network transactions with family and friends. Only professionals provided more support than they received from patients. Providing emotional support to others was positively correlated with positive affect, community integration, and mastery. Respondents reported more supportive than unsupportive transactions with network members and more supportive transactions with friends than with family or professionals. Finally, residents of supportive apartments and group homes provided and received support more frequently than residents of board-and-care homes. We discuss the results in terms of their implications for policy and future research.

Adaptation, Psychological↗
PubMed1992

Thrombolysis and coronary occlusion: effects upon the non-infarct zone.

Regional wall motion was examined by angiography after 3 weeks in 154 patients taking part in the Thrombolysis in Coronary Occlusion (TICO) Trial. Coronary patency rate was greater after administration of recombinant tissue plasminogen activator, (rt-PA 62/77pts 81%) than after a placebo (P 49/77pts 64% P = 0.02), particularly for the left anterior descending artery compared with the right coronary artery (LAD 27/28 96% vs RCA 28/40 70% P = 0.006). Left ventricular ejection fraction (LVEF) was preserved after rt-PA (rt-PA 59 +/- 14% vs P 53 +/- 15% P = 0.01), predominantly because of more effective non-infarct zone contraction (rt-PA 0.52 +/- 1.16 SD/cord vs P 1.01 +/- 1.07 SD/cord P = 0.008). Infarct zone scores differed little (rt-PA 2.88 +/- 0.95 SD/cord vs P 3.16 +/- 1.11 SD/cord P = 0.09). Left ventricular ejection fraction and non-infarct zone function were best preserved after rt-PA compared with the placebo, particularly in patients with single vessel disease and in patients in whom the infarct-related artery was the left anterior descending vessel.

Adult↗
PubMed1991

Cancer control and the older person. Prevention and detection in older persons.

Older persons are appropriate targets for a range of prevention and early detection interventions, however, greater emphasis should be given to structuring the delivery of prevention and detection services to the special needs of this population. This may require research and program development to reach older persons in the most effective and cost-effective manner. The American Cancer Society and other program efforts must accommodate the heterogeneity and special needs of segments of the older population. Racial and cultural minorities, impoverished persons, the cognitively impaired, and the physically impaired are four groups requiring special attention. Early detection guidelines specific to older persons should be developed.

Aged↗
PubMed1991

Morphological transformation and DNA adduct formation by benz[j]aceanthrylene and its metabolites in C3H10T1/2CL8 cells: evidence for both cyclopenta-ring and bay-region metabolic activation pathways.

Benz[j]aceanthrylene (B[j]A), a cyclopenta-fused polycyclic aromatic hydrocarbon related to 3-methylcholanthrene, has been studied to identify the major routes of metabolic activation in transformable C3H10T1/2CL8 (C3H10T1/2) mouse embryo fibroblasts in culture. Previous studies have reported that the major (55% of total) B[j]A metabolite formed by C3H10T1/2 cells was (+/-)-trans-9,10-dihydro-9,10-dihydroxy-B[j]A (B[j]A-9,10-diol), the dihydrodiol in the bay-region ring, with moderate amounts (14% of total) of (+/-)-trans-1,2-dihydro-1,2-dihydroxy-B[j]A (B[j]A-1,2-diol), the cyclopenta-ring dihydrodiol. The morphological transforming activities of three potential intermediates formed by metabolism of B[j]A by C3H10T1/2 cells, (+/-)-anti-trans-9,10-dihydro-9,10-dihydroxy-B[j]A-7,8-oxide (B[j]A-diol-epoxide), B[j]A-9,10-oxide, and B[j]A-1,2-oxide as well as the two B[j]A-dihydrodiols were examined. B[j]A, B[j]A-diol-epoxide, B[j]A-1,2-oxide, and B[j]A-9,10-diol were found to have moderate to strong activities with B[j]A-diol-epoxide the most active compared to B[j]A, while B[j]A-1,2-diol was inactive. B[j]A-9,10-oxide was found to be a weak transforming agent. At 0.5 microgram/ml, the following percentage of dishes with type II or III foci were observed: B[j]A, 59%; B[j]A-diol-epoxide, 75%; B[j]A-1,2-oxide, 25%; and B[j]A-9,10-diol, 17%. DNA adducts of B[j]A, B[j]A-9,10-diol, B[j]A-diol-epoxide, B[j]A-9,10-oxide, and B[j]A-1,2-oxide in C3H10T1/2 cells were isolated, separated, identified, and quantitated using the 32P-postlabeling method. B[j]A forms two major groups of adducts: one group of adducts is the result of the interaction of B[j]A-1,2-oxide with 2'-deoxyguanosine and 2'-deoxyadenosine; the second group of adducts is a result of the interaction of B[j]A-diol-epoxide with 2'-deoxyguanosine and 2'-deoxyadenosine. Qualitative and quantitative analysis of the postlabeling data suggests that B[j]A is metabolically activated by two distinct routes, the bay-region diol-epoxide route and the cyclopenta-ring oxide route, the former being the most significant.

Animals↗
PubMed1991

DNA adducts in rat lung, liver and peripheral blood lymphocytes produced by i.p. administration of benzo[a]pyrene metabolites and derivatives.

DNA adducts produced in vivo in rat lung, liver and peripheral blood lymphocytes following the i.p. administration of several synthetic benzo[a]pyrene (B[a]P) metabolites and ring-substituted derivatives have been analyzed by the nuclease P1 version of the 32P-postlabeling assay. These include 1-, 2-, 3-, 4-, 5-, 6-, 7-, 8-, 9-, 10-, 11- and 12-hydroxy-B[a]P, (+/-)-B[a]P-trans-4,5-dihydrodiol, (+/-)-B[a]P-trans-7,8-dihydrodiol, (+/-)-B[a]P-trans-9,10-dihydrodiol and B[a]P-7,8-dione. Among the monohydroxy derivatives, only 2-, 9- and 12-hydroxy-B[a]P produced detectable adducts. The only disubstituted derivative studied that produced adducts was the trans-7,8-dihydrodiol. The resulting DNA adducts were compared to those produced in each tissue by administration of B[a]P. 9-Hydroxy-B[a]P and B[a]P-trans-7,8-dihydrodiol each lead to the formation of major B[a]P adducts seen in lung and liver respectively. None of the adducts derived from either 2-hydroxy-B[a]P or 12-hydroxy-B[a]P were observed following administration of B[a]P alone.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗
PubMed1991

Conservative treatment of Grade III acromioclavicular dislocations.

Twenty-two patients with Grade III acromioclavicular (AC) joint dislocations were treated nonoperatively and evaluated by questionnaire, physical exam, and isokinetic strength and endurance testing. The mean follow-up time was 2.6 years (range, six months to 7.7 years). Patients returned to work an average of 2.1 weeks after injury. All of the patients were right-handed; 14 injured their dominant right AC joint whereas eight injured their nondominant left side. Isokinetic muscle testing was used to evaluate the strength and endurance of both shoulders in all 22 patients. Strength was measured as peak torque for shoulder flexion, extension, internal and external rotation, abduction, and adduction at 400 degrees per second. Internal and external rotation testing was also evaluated at 60 degrees per second. Endurance was measured at 400 degrees per second for flexion, extension, and internal and external rotation. The strength and endurance levels of the injured shoulders were comparable to the noninjured side. Although discomfort levels were low, long range follow-up reports reveal discomfort appearing with increased intensity of activity.

Acromioclavicular Joint↗
PubMed1990

Formation and persistence of novel benzo(a)pyrene adducts in rat lung, liver, and peripheral blood lymphocyte DNA.

Male CD rats were injected with single i.p. doses of benzo(a)pyrene (B(a)P), and peripheral blood lymphocytes (PBLs), livers, and lungs were removed at various times after administration. DNA adducts were analyzed in each tissue by 32P postlabeling with nuclease P1 enhancement. Sister chromatid exchange frequencies were concomitantly measured in cultured whole blood. B(a)P-DNA adducts were observed in all three tissues from animals sacrificed between 1 and 56 days after injection. Maximal adduction levels occurred at about 4 days after administration, followed by a gradual loss of adducts over the period examined. The apparent half-lives of total DNA adducts were 15 days in liver, 17 days in PBLs, and 22 days in lung. Induced sister chromatid exchanges were linearly related to the amount of DNA adducts remaining in the PBLs at the time of harvest up to 56 days and were significantly elevated above concurrent controls up to 14 days. One of the major adducts found in each tissue was N2-(10 beta-[7 beta,8 alpha,9 alpha-trihydroxy-7,8,9,10-tetrahydrobenzo(a) pyrene]yl)deoxyguanosine. An additional novel major adduct was found in the liver DNA and is derived from the further metabolism of B(a)P-trans-7,8-dihydrodiol. A second major novel B(a)P adduct was found in the DNA of lung tissues and accounts for about 40% of the total adducts present. Experimental evidence suggests that this adduct is derived from a metabolic pathway that includes the formation of 9-hydroxy-B(a)P.

Adenosine Triphosphate↗
PubMed1990

Health and medicine in Nicaragua.

A mass of statistics indicates that the health of the nation as a whole has benefited under the Sandinistas' unified health system. Nevertheless, many physicians and the principal coalition of opposition parties that will oppose the Ortega regime in this month's election advocate replacing it with a three-tiered system aimed at different segments of the population.

Attitude of Health Personnel↗
PubMed1989

Life strains, coping, and emotional well-being: a longitudinal study of recently separated and married women.

The stress and coping paradigm was used as the framework for a longitudinal study of recently separated and married women. Data were gathered at three different interviews over a period of 18 months. Comparing the two groups of women, it was found that life strains in the areas of financial concerns and spouse relations were related to both income level and marital status, with low-income and separated women experiencing the highest levels of these strains. Also, the separated women used coping strategies emphasizing personal change and reported more positive changes related to their family, work, and material conditions. Regression analyses on the entire sample showed that life strains were inversely related to emotional well-being and that coping served a stress-buffering function. It was concluded that the emotional well-being of separated and married women must be considered in the context of stress, coping, and change processes.

Adaptation, Psychological↗
PubMed1989

Organic and inorganic lead inhibit neurite growth in vertebrate and invertebrate neurons in culture.

Neurons from brains of chick embryos and pond snails (Lymnaea stagnalis) were cultured for 3 to 4 d in the presence of no toxins, inorganic lead (PbCl2), or organic lead (triethyl lead chloride). In chick neurons, inorganic lead reduced the percentage of cells that grew neurites (IC50 = 270 microM total lead, approximately 70 nM free Pb2+) but did not reduce the number of neurites per cell or the mean neurite length. Triethyl lead reduced the percentage of cells that grew neurites (IC50 = 0.24 microM) and the mean neurite length (extrapolated IC50 = 3.6 microM) but did not reduce the number of neurites per cell. In Lymnaea neurons, inorganic lead reduced the percentage of cells that grew neurites (IC50 = 13 microM total lead; approximately 10 nM free Pb2+). Triethyl lead reduced the percentage of cells that grew neurites (IC50 = 0.4 microM) and exerted significant toxicity at 0.2 microM. The two forms of lead affected neurite growth in qualitatively different ways, which suggests that their mechanisms of action are different.

Animals↗
PubMed1989

Development of a 12 element annular array transducer for realtime ultrasound imaging.

While the recent proliferation of ultrasound scanners based on annular array transducers has attracted widespread attention, very little published information is available on the physics, design criteria, and signal processing aspects of these instruments. In this paper, the first of a two part report, we describe the development and characterization of an annular array transducer for realtime medical imaging. Theoretical modeling of the pulsed fields of annular arrays is used to study and optimize array parameters. The factors which affect resolution and contrast in imaging--beam width, sidelobe levels, number of annuli, depth of field, and delay quantization--are discussed. A 12 element, 4.5 MHz, 30 mm design is adopted. Theoretical predictions showed excellent agreement with device measurements over a range of f-numbers (local/length/diameter) from f/1 to f/6.7 (30 to 200 mm range). Focusing to f/1 is an important advance in the state-of-the-art. A two transmit zone, dynamic receive configuration of array operation to exploit the f/1 focusing ability is proposed for realtime imaging.

Equipment Design↗
PubMed1989

Bronchoalveolar lavage plasmacytosis in a patient with a plasma cell dyscrasia.

A patient with serum monoclonal gammopathy, Bence-Jones proteinuria, and bone marrow plasmacytosis underwent fiberoptic bronchoscopic study for evaluation of interstitial lung disease. Bronchoalveolar lavage fluid contained 47 percent plasma cells, which were monoclonal by immunoperoxidase staining. This is the first time BAL plasmacytosis has been demonstrated in a patient with a plasma cell dyscrasia.

Aged↗
PubMed1988

Evaluation of a social problem-solving skills program for third- and fourth-grade students.

The effects of a social problem-solving (SPS) training program for entire classrooms of third- and fourth-grade children were examined in two studies. In the first study, experimental children showed significantly greater improvement in knowledge and performance of SPS skills than control children. However, both positive and negative effects of the intervention (varying by classroom) were found on measures of behavioral adjustment, self-efficacy, and peer acceptance at a 6-month follow-up. The second study compared two different intervention strategies: (a) SPS training with teacher-student dialoguing, peer pairing, and self-monitoring, and (b) SPS training with dialoguing only. It was found that children in both the experimental and control groups improved significantly in performance of SPS skills but no differences between the groups were found for changes in behavioral adjustment, self-efficacy, and peer acceptance. The limitations of cognitively mediated interventions for young children were discussed.

Affect↗
PubMed1988

The relationship between long-term psychiatric clients' psychological well-being and their perceptions of housing and social support.

This research tested hypotheses derived from motivation-hygiene theory that housing and social support would be differentially related to long-term psychiatric clients' Positive Affect and Negative Affect. The participants were 89 people between the ages of 18 and 65, who had been hospitalized for psychiatric problems at least twice and who had been diagnosed as schizophrenic, chronic depressive, or manic-depressive. Results indicated that the number of Housing Concerns was positively correlated with Negative Affect but not Positive Affect. Support Satisfaction was negatively correlated with Negative Affect, and Frequency of Support was positively correlated with Positive Affect. Interactions between the housing variable and Network Size were found for both Positive Affect and Negative Affect, thus supporting the stress-buffering hypothesis. The findings provided mixed support for motivation-hygiene theory.

Adult↗
PubMed1988

Influence of mastectomy technique on sex steroid receptor analysis.

Accurate analysis of hormone receptors in breast carcinoma is critical from prognostic and therapeutic standpoints. Controversy exists over whether there is receptor decay when specimens are obtained upon completion of, rather than prior to, mastectomy. In addition, the effect of mastectomy technique on receptor concentration has not been addressed. Twenty patients with breast carcinoma had biopsy specimens taken prior to and upon completion of modified radical mastectomy. Ten had axillary dissection followed by mastectomy (Group A). The others had mobilization of the breast before axillary dissection (Group B). The estrogen receptor concentration was higher in 14 of 20 premastectomy specimens. All 10 patients in Group B had positive receptors before mastectomy; 5 were negative after mastectomy. All seven patients in Group A with positive premastectomy receptors remained so postmastectomy. We concluded that if a tumor specimen for receptor analysis is not obtained prior to modified radical mastectomy, axillary dissection should precede breast mobilization.

Axilla↗