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Biomedical subjects

P Anderson

Publications and source records attributed to P Anderson.

At least 73 records · Page 4Linked to original sources
PubMed2001

Managing workplace stress in a dynamic environment.

Workplace stress can be either positive or negative. While positive stress is desirable for a variety of reasons, negative stress is not. In fact, the latter can result in dysfunctional consequences for health care organizations due to altered behavior such as increased absenteeism, changes in work habits, and job burnout. Management can intervene to reverse the effects of negative stress. Some actions include proper job design, ongoing communication with employees, team building, and use of a group coordinator.

Humans↗
PubMed2001

A positive look at progressive discipline.

Health care organizations must employ individuals whose performance meets job standards in order to be successful in today's dynamic health care environment. Use of an effective progressive discipline program is one technique to accomplish this objective. This article explores reasons for using progressive discipline, explanations for why supervisors avoid taking disciplinary action, benefits of progressive discipline, the four stages of a progressive discipline procedure, and exceptions to applying progressive discipline.

Administrative Personnel↗
PubMed2001

Intranasal immunization with killed unencapsulated whole cells prevents colonization and invasive disease by capsulated pneumococci.

A whole-cell killed unencapsulated pneumococcal vaccine given by the intranasal route with cholera toxin as an adjuvant was tested in two animal models. This vaccination was highly effective in preventing nasopharyngeal colonization with an encapsulated serotype 6B strain in mice and also conferred protection against illness and death in rats inoculated intrathoracically with a highly encapsulated serotype 3 strain. When the serotype 3 challenge strain was incubated in the sera of immunized rats, it was no longer virulent in an infant-rat sepsis model, indicating that the intranasal immunization elicited protective systemic antibodies. These studies suggest that killed whole-cell unencapsulated pneumococci given intranasally with an adjuvant may provide multitypic protection against capsulated pneumococci.

Adjuvants, Immunologic↗
PubMed2001

Development of executive functions through late childhood and adolescence in an Australian sample.

Although there have been significant theoretical advances in the field of child neuropsychology, developmental features of adolescence have received less attention. Progress in clinical practice is restricted due to a lack of well-standardized, developmentally appropriate assessment techniques. This article addresses these issues in relation to executive skills. These abilities are targeted for 2 reasons: first, because they are often considered to be mature during late childhood and adolescence, despite limited investigation in this age range; and second, because of their central importance to efficient day-to-day functioning. Using a normative sample of 138 children, aged 11.0 to 17.11 years, this article plots the development of executive skills through late childhood and early adolescence and interprets progress in these skills with reference to current neurological and cognitive theory.

Adolescent↗
PubMed2001

Latino AIDS immigrants in the Western Gulf states: a different population and the need for innovative prevention strategies.

Immigrant HIV infected Latinos, and those at highest risk for infection, demonstrate strikingly different patterns of risk behaviors and origins. This complicates the already complex acculturation process impacting their lives. By weaving together immigration and AIDS epidemiological patterns, the impact of tightening immigration policy, and masked sexual behaviors, the authors express concern for a lack of communication with, and lack of health care access for, Latinos in the Western Gulf Coast. To combat this deficit, health care and social workers need to be aware of different social, cultural, and behavioral contexts in Latino populations. Policy makers should support efforts to provide health care workers with skills through appropriate language and cultural sensitivity workshops. HIV prevention strategies specific to Latinos are also discussed.

Acculturation↗
PubMed2001

Enhanced survival of porcine neural xenografts in mice lacking CD1d1, but no effect of NK1.1 depletion.

Transplantation of embryonic porcine neurons may restore neurological function in patients with Parkinson's disease, if immunological rejection could be prevented. This study was performed to investigate the role of natural killer cells (NK cells) and NK1.1+ T cells (NK T cells) in the rejection of neural xenografts. A cell suspension was prepared from the ventral mesencephalon of 26-27-day-old pig embryos, and 2 microl was implanted in the right striata of mutant CD1d1 null (CD1.1-/-) mice, NK1.1-depleted mice, and controls. The CD1.1-/- mice are deficient in NK T cells and the antigen-presenting molecule CD1d1. Graft survival and host responses were determined immunohistochemically using markers for dopamine neurons, CD4-, CD8- cells, microglia, and macrophages. At 2 weeks, the grafts were significantly larger in CD1.1-/- mice, 0.09 +/- 0.02 microl (mean +/- SEM), compared with controls, 0.05 +/- 0.01 microl. There was no significant difference between NK1.1-depleted mice, 0.02 +/- 0.01 microl, and controls. At 5 weeks, two grafts were still present in the CD1-/- mice, whereas only scars remained in the controls and in the NK1.1-depleted mice. Immune reactions were strong at 2 weeks and less pronounced at 5 weeks in all groups. Microglial activation was lower in NK-depleted mice than in the controls at 2 weeks. In contrast to organ xenografting, NK1.1+ cells do not seem to be important mediators of the rejection of discordant cellular neural xenografts. However, our results suggest that the antigen-presenting molecule CD1d1 may be involved in the rejection process.

Animals↗
PubMed2001

Microtomographic analysis of subsurface enamel and dentine following Er:YAG laser and acid etching.

The Er:YAG laser, with or without phosphoric acid, is used to promote enamel surface changes to increase restorative material retention. However, such irradiation might induce subsurface enamel damage. In the present study, X-ray microtomography was used to compare the subsurface enamel beneath laser and acid conditioned; laser-only etched and acid-only etched surfaces. Laser and acid conditioning increased the etching depth, but did not induce significant damage in the enamel subsurface. Analysis of the laser-only etched enamel subsurface revealed a small reduction in mineral concentration suggesting an increase in porosity, allowing greater penetration of acid and resulting in an increased acid-etch depth.

Acid Etching, Dental↗
PubMed2000

Dynamic shuttling of TIA-1 accompanies the recruitment of mRNA to mammalian stress granules.

Mammalian stress granules (SGs) harbor untranslated mRNAs that accumulate in cells exposed to environmental stress. Drugs that stabilize polysomes (emetine) inhibit the assembly of SGs, whereas drugs that destabilize polysomes (puromycin) promote the assembly of SGs. Moreover, emetine dissolves preformed SGs as it promotes the assembly of polysomes, suggesting that these mRNP species (i.e., SGs and polysomes) exist in equilibrium. We used green flourescent protein-tagged SG-associated RNA-binding proteins (specifically, TIA-1 and poly[A] binding protein [PABP-I]) to monitor SG assembly, disassembly, and turnover in live cells. Fluorescence recovery after photobleaching shows that both TIA-1 and PABP-I rapidly and continuously shuttle in and out of SGs, indicating that the assembly of SGs is a highly dynamic process. This unexpected result leads us to propose that mammalian SGs are sites at which untranslated mRNAs are sorted and processed for either reinitiation, degradation, or packaging into stable nonpolysomal mRNP complexes. A truncation mutant of TIA-1 (TIA-1DeltaRRM), which acts as a transdominant inhibitor of SG assembly, promotes the expression of cotransfected reporter genes in COS transfectants, suggesting that this process of mRNA triage might, directly or indirectly, influence protein expression.

Animals↗
PubMed2000

Unproductively spliced ribosomal protein mRNAs are natural targets of mRNA surveillance in C. elegans.

Messenger RNA surveillance, the selective and rapid degradation of mRNAs containing premature stop codons, occurs in all eukaryotes tested. The biological role of this decay pathway, however, is not well understood. To identify natural substrates of mRNA surveillance, we used a cDNA-based representational difference analysis to identify mRNAs whose abundance increases in Caenorhabditis elegans smg(-) mutants, which are deficient for mRNA surveillance. Alternatively spliced mRNAs of genes encoding ribosomal proteins L3, L7a, L10a, and L12 are abundant natural targets of mRNA surveillance. Each of these genes expresses two distinct mRNAs. A productively spliced mRNA, whose abundance does not change in smg(-) mutants, encodes a normal, full-length, ribosomal protein. An unproductively spliced mRNA, whose abundance increases dramatically in smg(-) mutants, contains premature stop codons because of incomplete removal of an alternatively spliced intron. In transgenic animals expressing elevated quantities of RPL-12, a greater proportion of endogenous rpl-12 transcript is spliced unproductively. Thus, RPL-12 appears to autoregulate its own splicing, with unproductively spliced mRNAs being degraded by mRNA surveillance. We demonstrate further that alternative splicing of rpl introns is conserved among widely diverged nematodes. Our results suggest that one important role of mRNA surveillance is to eliminate unproductive by-products of gene regulation.

Alternative Splicing↗
PubMed2000

TIA-1 is a translational silencer that selectively regulates the expression of TNF-alpha.

TIA-1 and TIAR are related proteins that bind to an AU-rich element (ARE) in the 3' untranslated region of tumor necrosis factor alpha (TNF-alpha) transcripts. To determine the functional significance of this interaction, we used homologous recombination to produce mutant mice lacking TIA-1. Although lipopolysaccharide (LPS)-stimulated macrophages derived from wild-type and TIA-1(-/-) mice express similar amounts of TNF-alpha transcripts, macrophages lacking TIA-1 produce significantly more TNF-alpha protein than wild-type controls. The half-life of TNF-alpha transcripts is similar in wild-type and TIA-1(-/-) macrophages, indicating that TIA-1 does not regulate transcript stability. Rather, the absence of TIA-1 significantly increases the proportion of TNF-alpha transcripts that associate with polysomes, suggesting that TIA-1 normally functions as a translational silencer. TIA-1 does not appear to regulate the production of interleukin 1 beta, granulocyte-macrophage colony-stimulating factor or interferon gamma, indicating that its effects are, at least partially, transcript specific. Mice lacking TIA-1 are hypersensitive to the toxic effects of LPS, indicating that this translational control pathway may regulate the organismal response to microbial stress.

3' Untranslated Regions↗
PubMed2000

Pulmonary mononuclear cell responses to antigens of Mycobacterium tuberculosis in healthy household contacts of patients with active tuberculosis and healthy controls from the community.

Protective immunity against Mycobacterium tuberculosis requires CD4+ lymphocyte-mediated immune responses and IFN-gamma activity. As the primary portal of entry of M. tuberculosis is the lung, pulmonary immune responses against multiple M. tuberculosis Ags were compared between both M. tuberculosis-exposed tuberculin skin test-positive healthy household contacts (HHC) of patients with active sputum smear and culture-positive tuberculosis and tuberculin skin test-positive healthy control individuals from the community (CC). Frequencies of M. tuberculosis Ag-specific IFN-gamma-producing cells, IFN-gamma concentrations in culture supernatants, and DNA synthesis in bronchoalveolar cells (BAC) and PBMC were studied in HHC (n = 10) and CC (n = 15). Using enzyme-linked immunospot assay we found higher frequencies of IFN-gamma-producing cells with specificity to M. tuberculosis-secreted Ag 85 (Ag 85) in BAC from HHC than in BAC from CC (p < 0.022) and relative to autologous PBMC, indicating compartmentalization of Ag 85-specific cells to the lungs. Further, IFN-gamma-producing cells with specificity to components A and B of Ag 85 were specifically compartmentalized to the lungs in HHC (p < 0. 05). IFN-gamma concentrations in culture supernatants of BAC and Ag-specific DNA synthesis were low and comparable in the two subject groups. Increased immune responses to Ag 85 at the site of repeated exposure to M. tuberculosis (the lung) may represent an important component of protective immunity against M. tuberculosis. Correlates of protective immunity against M. tuberculosis are required for assessment of the efficiency of anti-tuberculous vaccines.

Acyltransferases↗
PubMed2000

Accuracy of the extent of axillary nodal positivity related to primary tumor size, number of involved nodes, and number of nodes examined.

PURPOSE: While a number of studies have evaluated the minimum number of axillary nodes that need to be examined to accurately determine nodal positivity or negativity, there is little information on the number of nodes which must be examined to determine the extent of nodal positivity. This study attempts to determine for patients with 1-3 positive nodes the probability that the number of positive nodes reported is the true number of positive nodes as well as the probability that 4 or more nodes could be positive based on primary tumor size and number of nodes examined. MATERIALS AND METHODS: From 1979 to 1998, 1652 women with Stages I-II invasive breast cancer underwent an axillary dissection as part of their breast conservation therapy and had more than 10 lymph nodes examined. The mean and median number of nodes identified in the dissection was 19 and 17 (range, 11-75). The median age was 55 years. A total of 1155 women had T1 tumors and 497 had T2 tumors. Of the 459 node-positive women, 72% had 1-3 positive nodes, 18% had 4-9 positive nodes, and 10% had 10 or more positive nodes. A mathematical model based on tumor size and number of nodes examined was created using the hypergeometric distribution and Bayes Theorem. The resulting model was used to estimate the accuracy of the reported number of positive nodes and the probability of 4 or more positive nodes based on various observed sampling combinations. RESULTS: For patients with T1 tumors and 1, 2, or 3 positive nodes, the minimum number of nodes examined needed for a 90% probability of accuracy is 19, 20, and 20. For T2 tumors and 1, 2, or 3 positive nodes, a minimum of 20 nodes is required. The probability of 4 or more positive nodes increases as tumor size and the number of reported positive nodes increase and as the number of examined nodes decreases. For a 10% or less probability of 4 or more positive nodes, a patient with a T1 tumor and 1, 2, or 3 observed positive nodes would require a minimum of 8, 15, and 20 nodes removed. For a T2 tumor and 1, 2, or 3 observed positive nodes, the corresponding numbers are 10, 16, and 20. CONCLUSION: The accuracy of the extent of axillary nodal positivity is influenced by the number of observed positive nodes, tumor size, and the number of nodes examined. Underestimation of the number of positive nodes will result in errors in the assessment of an individual's risk for locoregional recurrence, distant disease, and breast cancer death and will adversely impact on treatment recommendations. This model provides the clinician with a means for assessing the accuracy of the number of positive nodes reported in patients with 1-3 positive nodes.

Adult↗
PubMed2000

Anti-stress effects of dehydroepiandrosterone: protection of rats against repeated immobilization stress-induced weight loss, glucocorticoid receptor production, and lipid peroxidation.

In the present study, we have (i) examined the biological effects of repeated immobilization stress, and (ii) tested the hypothesis that the adrenal steroid hormone dehydroepiandrosterone (DHEA) is an anti-stress hormone, using male Sprague-Dawley rats. Rats (N = 6) were divided into the following four groups: (i) control, (ii) repeated immobilization stress (2 hr daily, for 60 days), (iii) repeated immobilization stress (2 hr daily, for 60 days) plus daily i.p. administration of 5 mg DHEA/0.1 mL DMSO, and (i.v.) daily i.p. administration of 5 mg DHEA/0.1 mL DMSO alone. Results obtained showed that repeated immobilization stress resulted in a significant (25%) inhibition in body weight gain, a significant increase in adrenal weight, an increase in glucocorticoid receptor (GR) in the liver, thymus, and spleen, decreased plasma triglyceride levels, and increased lipid peroxidation in the liver and heart as compared with control unstressed animals. Interestingly, DHEA administration resulted in a significant reversal in stress-induced inhibition in body weight gain, adrenal weight, GR levels in liver, thymus, and spleen, and lipid peroxidation levels in the liver and heart. In addition, animals treated with DHEA alone without stress showed a significant (15%) inhibition in body weight gain and an almost 60% decrease in plasma triglyceride levels as compared with control unstressed animals. It is concluded that DHEA acts as an anti-stress hormone in rats, as shown in its antagonizing the effects of repeated immobilization stress on total body weight, adrenal weight, GR levels, and free radical generation.

Animals↗
PubMed2000

Cytokine-induced Src homology 2 protein (CIS) promotes T cell receptor-mediated proliferation and prolongs survival of activated T cells.

Members of the suppressor of cytokine signaling (SOCS) family were discovered as negative regulators of cytokine signaling by inhibition of the Janus kinase-signal transducer and activator of transcription (Jak-STAT) pathway. Among them, cytokine-induced Src homology 2 (SH2) protein (CIS) was found to inhibit the interleukin 3- and erythropietin-mediated STAT5 signaling pathway. However, involvement of SOCS proteins in other signaling pathways is still unknown. This study shows that the expression of CIS is selectively induced in T cells after T cell receptor (TCR) stimulation. In transgenic mice, with selective expression of CIS in CD4 T cells, elevated CIS strongly promotes TCR-mediated proliferation and cytokine production in vitro, and superantigen-induced T cell activation in vivo. Forced expression of CIS also prolongs survival of CD4 T cells after TCR activation. Molecular events immediately downstream from the TCR are not changed in CIS-expressing CD4 T cells, but activation of mitogen-activated protein (MAP) kinase pathways by TCR stimulation is significantly enhanced. Together with the increased MAP kinase activation, a direct interaction of CIS and protein kinase Ctheta was also demonstrated. These results suggest that CIS is one of the important regulators of TCR-mediated T cell activation. The functions of CIS, enhancing TCR signaling and inhibiting cytokine signaling, may be important in the regulation of immune response and homeostasis.

Animals↗
PubMed2000

Death, autoantigen modifications, and tolerance.

Autoantibodies present in the serum of patients with a variety of inflammatory diseases have proven useful as diagnostic markers and as probes with which to elucidate biochemical and signaling pathways. The mechanisms governing the generation of autoantibodies remain elusive, constituting a critical missing link in our understanding of rheumatologic illnesses. Several lines of experimentation in recent years have strongly implicated events surrounding cell death in this process. This review will address the potential role played by death-specific modifications of autoantigens in bypassing tolerance to highly conserved autoantigens, including nucleic acids, lipids, and proteins.

Animals↗